The fourth-generation synchrotron light sources aim to achieve ultralow emittances and have very small dynamic aperture, which are expected to adopt on-axis injection schemes. Lower frequency rf systems are required for a large separation between RF buckets due to the limitations of kicker. We designed a 166.6 MHz normal conducting cavity with HOM damped used for the main cavity of storage...
This paper presents the design concept of the dipole magnet with 50 mm aperture, 20 T nominal field and 13% margin based on a six-layer cos-theta (CT) hybrid coil design. Due to the high stresses and strains in the coil at high field, Stress Management (SM) elements are implemented in the CT coil geometry. The results of magnet magnetic analysis are presented and discussed. The key parameters...
Seen in the light of finding ways to reduce the CO2 footprint in the Big Science world and at the same time make big saving in operating cost due to 90% lower LHe consumption I will in the presentation share the following insights:
1) initial idea and economic business case for 10-20 kA current leads
2) the 13 kA Hybrid Current Lead design by using LN2
3) the application in a test...
The control of beam emittance growth in high-current Radio Frequency Quadrupole (RFQ) accelerator is fairly challenging because of the strong space charge effect. The transverse beam emittance growth in the RFQ is well controlled in many international high power accelerator projects, while the longitudinal beam emittance growth is really significant which affects the beam transmission in the...
Additive manufacturing is a promising approach to reduce production costs for high-frequency cavities while increasing design freedom. This potential will be evaluated through studies on several cavity prototypes and their performance. Especially for the evaluation of the field distribution in cm-sized S-band cavities and thus the shunt impedance, the development of a measurement setup for...
An important problem in present accelerators is the determination of the electromagnetic (EM) wakefields and their effect in the machine performance. These wakefields are generated inside the accelerator vacuum chamber due to the interaction of the particle beam with the surrounding structure. Among the properties that characterize their impact on the machine are the beam coupling Impedance in...
Due to a recent interest in scanning thinner containers such as cars or aviation unit load devices (ULDs), lower energy linac solutions are required in order to obtain sufficient image contrast. In this work, we present the complete design of a C-band, bi-periodic, 2 MeV electron linac to fulfil this need. Multi-objective optimisation techniques are employed to optimise the RF cavities for...
Fringe fields at the entrance and exit of multipole magnets can adversely affect the dynamics of particles in the beam, but there is also the possibility that fringe fields of the right form could be used to enhance the accelerator performance. Accelerator design work could benefit from efficient and realistic models of multipole fringe fields at an early stage in the design process. We...
Thanks to recent evolutions of electromagnetic computer-aided engineering tools, nowadays the simulation of complex particle accelerator components is feasible by commercial software packages. A practical limitation of these tools is strictly related to the solver ability to discretize real devices’ material and geometry into a numerical model, which, in some particular situations, could lead...
Due to the beam in the storage ring has a very low vertical emittance. The angular dispersion induced microbunching (ADM) scheme is used to generate high brightness coherent synchrotron radiation. To apply a similar scheme in a linear accelerator, it is necessary to reduce the vertical emittance of the beam in the linear accelerator. Generally, angular-momentum-dominated round beams can be...
Grid-controlled electron gun usually uses specially designed power supplies to supply power, the performance of the power supplies can directly affect the beam performance of the accelerator. In this paper, a nanosecond power supply for a grid-controlled electron gun is designed. It uses avalanche transistors and superimposes Marx generators to improve the power. Finally, its rise edge is less...
For the Elettra 2.0 upgrade project, a new class of DC power converters have been internally designed and eventually installed in a number of around 1000 pieces to power multipole and corrector magnets in the synchrotron storage ring. In order to fulfill evolving scenarios over the expected lifecycle of the accelerator, the power converters will be supervised by one of the most advanced...
Organic and inorganic Optical Fibers (OFs) are increasingly utilized in space and medical applications, including accelerator and reactor environments to monitor beam currents and shapes, doses, temperatures, and pressures [1-5]. OFs are ideal as they can be radiation hard, small in size, independent from electro-magnetic environments, and linear over a large measurement range. Here we present...
The tracking code PLACET is widely used in the linear collider community to simulate the beam dynamics. It is a powerful tool for analyzing the static and dynamic imperfections in the lattice and has many built-in correction techniques. The original PLACET code was written in C with a TCL interface. Detailed data analysis including plotting is often performed with other programming languages,...
Space charge forces represent main induced effects in an RF-injector that degrade the beam quality. In this scenario the laser distribution sent on the photocathode acquires an
important role in the emittance compensation process, as the slice analysis shows. A novel model of space charge forces is proposed for bunch with arbitrary charge distribution to derive expressions of self-induced...
Acceleration for a muon collider will have to be extremely fast to ensure efficient transmission of the decaying beams, with acceleration times of the order of 1ms. One of the proposals for such a machine is centered around a rapid cycling synchrotron (RCS), a hybrid lattice of cells with alternating superconducting and resistive dipole magnets. Resistive magnets will swing from negative to...
The Dynamic Aperture (DA) is an important concept for the study of non-linear beam dynamics in a circular accelerator. The DA is defined as the extent of the phase-space region in which the particle's motion remains bounded over a finite number of turns. Such a region is shaped by the imperfections in the magnetic fields, beam-beam effects, electron lens, electron clouds, and other nonlinear...
Klystrons and IOTs are widely used in accelerators as high-power RF sources. Development and optimization of klystron and IOT designs is aided by the use of different simulation tools, including highly efficient large-signal codes. We present an overview of the advances in the code development and modeling using Naval Research Laboratory (NRL) set of TESLA-family of large-signal codes,...
Vertical Fixed-Field Alternating Gradient (vFFA) accelerators exhibit particle orbits which move vertically during acceleration. This recently rediscovered circular accelerator type has several advantages over conventional ring accelerators, such as zero momentum compaction factor. At the same time, inherently non-planar orbits and a unique transverse coupling make controlling the beam...
Thus ends 63 years without a theory of longitudinal capture able to predict the final beam distribution and optimize the voltage law. We show the relationship between average values of the initial and final Hamiltonian is a universal function independent of voltage law, provided the adiabaticity parameter is small. The deviations from average are also given. This means the bunch profile and...
Design of circular lattices involves optimizing figures of merit (FoMs) characterizing the beam properties subject to the constraint that the beam distribution function be approximately periodic in trips around the lattice. We have developed an algorithm that accomplishes this with minimal computational effort. The algorithm takes advantage of recent developments in adjoint techniques * that...
It is often required to estimate the effect of small perturbations of design parameters on various performance metrics of RF sources as a part of optimization and sensitivity analysis. The direct approach, assuming an accurate simulation code is available, is to change slightly the value of an input variable of interest; a simple example is a calculation of how a small change in klystron...
High brightness electron beams enable a wide spectrum of applications ranging from short wavelength radiation sources to high gradient wakefield acceleration. The rich dynamics that are intrinsic in charged particles accelerated in complex systems require a careful description in the analysis and design of a given machine, particularly regarding its stability. Numerous computer codes are in...
The microbunching instability is one of the most significant effects,
which can lead to a severe degradation of the beam quality in the linac
section of free-electron lasers.
Direct analytical treatment of the microbunching instability is however
challenging.
In particular when multiple bunch compression stages are considered,
an exact closed-form expression for the charge density of...
The cost of a klystron for the SNS is estimated to be in the $200K range. A magnetron with the same power level is about one-fourth the cost. With ancillary equip-ment to functionally duplicate the performance of the klystron and allowing for the reduced lifetime of the magnetron compared to the klystron, about half the cost. Additional operational cost savings are related to the 805 MHz...
The ALBA synchotron operates in a Touschek dominated lifetime regime, which depends mainly on the momentum acceptance and the transverse beam size along the machine. Although in the current ALBA machine the RF dominates the momentum acceptance, this will not be the case for the foreseen upgrade of the machine ALBA-II. For this reason, we have developed an algorithm to optimize the beam...
While the design of the ALBA-II is in progress, it is required to assess the consequences of realistic imperfections such as alignment tolerances and magnetic errors. Compensation of insertion device induced optics variation has been studied, as well as the small impact on the emittance due the introduction of 3 T superbends. We demonstrate that non-linear optics is rather robust in the...
Hefei Advanced Light Facility (HALF), a planned key mega-science facility approved by the Chinese government in 14th five-year plan, will be constructed in Hefei, China, and National Synchrotron Radiation Laboratory (NSRL) is responsible for the construction. HALF is a 4th generation diffraction limited synchrotron radiation light source which includes a 240 m injector, a 180 m transport line,...
KIT operates the storage ring KARA (Karlsruhe Research Accelerator) as an accelerator test facility, which serves as a testbed for different electron beam-based experiments. Thus, it motivates to study the beam conditions extensively.
To extend the existing characterisation of non-linear parameters, the amplitude dependent tune shift (ADTS) was measured. ADTS is typically controlled by...
Many high intensity proton or ion accelerators employ sources with solenoidal magnetic fields that produce beams carrying a large amount of angular momentum. To simulate such beams, one has to generate a 4D transverse phase space distribution with the right amount of angular momentum as initial conditions. In this paper, we first show that such distributions can be obtained through different...
A new method is introduced to process the closed orbit modulation by two corrector magnets modulated with sinusoidal waveforms. The new method can extract linear optics information from tens of thousands of orbits and represent such information with only a few parameters per beam position monitor. The concise form makes it easy to fit for linear lattice errors. The method has been demonstrated...
Beam splitting can be performed by adiabatic crossing of a given one-dimensional non-linear resonance. This process is routinely used at the CERN PS to deliver the proton beam to the SPS fixed-target physics. To improve the efficiency of the intensity sharing between the various beamlets, a dipole kicker can be used to excite the beam during the resonance crossing process. This entails a...
We explore the physics of high-current electron beam propagation through the accelerating cells of linear induction accelerators (LIAs), using a field-adapted coordinate transformation that extends the usual rotating Larmor frame analysis to account for simultaneous acceleration. This is useful for LIAs, since the focusing solenoids must be integrated into the accelerating cells to transport...
Single-bunch instabilities are among the major effects limiting beam intensity in synchrotrons. In the case of a light source with ultra-low emittances, this might be a critical issue causing poor performance of the synchrotron. This study elaborates on the case of the Diamond-II storage ring showing the results of particle simulations for different configurations of the updated lattice and...
This study primarily discusses a unique topology for constructing a double full bridge circuit. The study establishes a push-pull inverter model and analyzes the balance circuit in its architecture. This allows the power supply to initiate the balance circuit and ensures the TPS booster magnet power supply operates smoothly in a safe and balanced voltage region when magnet energy is...
As part of the Diamond-II upgrade project, the booster synchrotron is due to be replaced with a low-emittance solution that enables efficient injection into the Diamond-II storage ring. The new booster lattice uses cells of combined-function gradient bends that integrate dipole, quadrupole and sextupole components into single magnets, alternating between focussing and defocussing bends....
For an integral part of electron-ion collider (EIC) de-sign, the crab crossing scheme provides a head-on collision for beams with a nonzero crossing angle. Recently we provided a framework for accurate numerical simulations of beam-beam effects with crabbing crossing dynamics. The framework was implemented in a simulation code package named “CASA BeamBeam”. We offer com-prehensive formulas for...
Formulae to compute the footprint (amplitude-dependent detunings) and Resonance driving terms RDT, generated by long-range beam-beam collisions and wire correctors have been implemented in a Python code. The paper briefly outlines the method and code and provides several examples of its usage. The maximum extent of the footprint (in geometric sense) can be efficiently computed.
We adopt the standard field matching technique to solve the general electromagnetic problem consisting of two parallel layers with arbitrary complex relative permittivity and permeability. Analytical formulae for the longitudinal impedance are discussed in the general case, and in the specific case of a two-layer system consisting of a metal-coated ceramic chamber. The solution of the...
The potential in the Radio Frequency Quadrupole (RFQ) can be expressed as a sum of a transverse multipolar expansion: $\sum_{m=1}^\infty{A_{0m}}\left(\frac{r}{r_0}\right)^{2m}\cos(2m\theta)$, and a longitudinal term expressed as sum of Bessel functions: $\sum_{m=0}^\infty\sum_{n=1}^\infty A_{nm}I_{2m}(nkr)\cos(2m\theta)\cos(nkz)$. Since the paper of Kapchinskii and Teplyakov...
Minimizing resonance driving terms (RDTs) is a traditional approach to enlarge the dynamic aperture (DA) of a storage ring. However, small RDTs can not guarantee a large DA. In this paper, the fluctuation of RDTs along the ring is taken into consideration. A large number of nonlinear lattice solutions based on one double-bend achromat lattice are analyzed. The results show that minimizing the...
The CERN Linear Electron Accelerator for Research (CLEAR) has been operating since 2017 as a user facility providing beams for a large variety of experiments. Its RF photocathode-based linear accelerator can accelerate electrons up to 220 MeV with a bunch charge of 0.1-1.5nC with single or up to 150 bunches per train. The flexibility of providing various beam parameters following user demands...
Transverse wigglers and wakefield structures are promising candidates for imparting arbitrary correlation on transverse and longitudinal phase spaces respectively. They provide sinusoidal electromagnetic fields that become building blocks for Fourier synthesis. We present the progress of arbitrary correlation generation using transverse wiggler and wakefield structures.
The CERN’s Electrical Power Converters group is responsible for around 4000 power converters controlled, monitored, and diagnosed using Function Generator/Controller (FGC) devices. These devices run either on in-house designed embedded hardware (FGC2, FGC3) or in Front-End Computers. The latter flavour of devices is encoded in the FGCDv1 framework, which also implements the logic interfacing...
CERN's North Area comprises several target and experimental systems and is a zone of interest for future development. Provision of beam to this area relies upon several beam-intercepting devices located in various branched transfer lines from the Super Proton Synchrotron. In several lines, these include a primary production target system of beryllium plates followed by a combined collimation,...
In ultralow-emittance synchrotron light sources, harmonic RF cavities are very useful to lengthen the beam bunches by which the adverse effects due to intrabeam scattering can be mitigated. We are developing a 1.5-GHz TM020-type normal-conducting harmonic cavity which is to be used for the KEK future light source project. The harmonic cavity using the TM020 resonant mode has distinct...
Beam Delivery Simulation (BDSIM) is a program based on Geant4 that creates 3D radiation transport models of accelerators from a simple optical description in a vastly reduced time with great flexibility. It also uses ROOT and CLHEP to create a single simulation model that can accurately track all particles species in an accelerator to predict and understand beam losses, secondary radiation,...
High luminosity electron-positron linear colliders constitute a fundamental instrument in the field of elementary particle physics. The ``Cool copper collider", or C3, is a proposal for a 250 COM GeV Higgs factory, with possible extension to the TeV-scale, and it represents a promising candidate for the near future high energy physics. The C3 infrastructure is conceived as a modular facility...
The accurate analysis of any possible source of beam instability is mandatory for the design of a new particle accelerator, especially for high current and ultra low emittance synchrotrons. In the specific case of instabilities driven by the coupling between the charged particle beam and the electromagnetic field excited by the beam itself, the corresponding effect is estimated through the...
The NEWGAIN (NEW GAnil INjector) project aims at supplying higher mass-to-charge ratio ions (from A/Q=3 to 7) with an energy of 590 keV/A to the present SC-Linac of SPIRAL2. It comprises a new SC source, a dogleg LEBT, an 88 MHz RFQ, and a MEBT, optimized for a current of up to 350 uA of uranium. Additionally, an extension of the present LEBT is considered to merge into the new one. This paper...
At EuPRAXIA@SPARC_LAB an X-ray FEL user facility is driven by a plasma accelerator in the particle-driven configuration where an ultra-relativistic beam, the driver, through a plasma generates a wake of charge density useful for accelerate a witness beam. The electron bunches are generated through the so-called comb technique in an RF injector that consist of a 1.6 cell S-band gun followed by...
The upgrade of the European XFEL to support a future high duty cycle (HDC) operation mode requires new design concepts for the photoinjector. In particular, the electron gun is crucial for achieving high quality beams at high peak currents. Among other variants, a 1.6-cell TESLA-type RF-gun is the preferable solution for the HDC EuXFEL. The SRF gun design, however, requires the application of...
At KEK a design of the compact 10 MeV, 50 mA accelerator for irradiation purpose was proposed. Current design includes a 100 kV thermionic DC electron gun with an RF grid, 1-cell normal-conducting buncher cavity, and Nb3Sn superconducting cavities to accelerate the beam to the final energy of 10 MeV. The goal of the present beam dynamics study is the beam loss suppression (to the ppm level),...
Accelerating technology is evolving towards compactness and high intensity. In such a scenario, beam loading effects result in significant energy losses for long trains of bunches. To address these effects, we generalised the Beam Loading module of the tracking code RF-Track to allow the study of beam loading independently of the particle type and velocity or the accelerating cavity design....
The Extremely Brilliant Source (EBS) at the European Synchrotron Radiation Facility (ESRF) is a 4th generation light source operating with a horizontal emittance of 135 pm. This low horizontal emittance reduces the lifetime in filling modes with high current per bunch. This will be alleviated in the future with an active 4th harmonic cavity. In order to simulate the effect of the 4th harmonic...
The Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab employs recirculating linac SRF technology to generate a high polarization 12 GeV electron beam
for nuclear physics users. New opportunities to study multipass energy recovery have also emerged with the proposal of a 5-pass energy recovery demonstration, ER@CEBAF. New beam optics with minimized beta functions have been...
Beam-beam effects are known to undermine the performance of the LHC during proton-proton collisions. In order to enhance the luminosity production and increase the tolerance of the working point of the machine after the High Luminosity upgrade of the LHC, it is relevant to study the possibility of using current-carrying wires to compensate long-range beam-beam effects. Following proof of...
In 2017, a proton-impact test HL-LHC collimator materials was carried out in the HiRadMat facility at CERN. The experiment, called “MultiMat”, enabled the testing of bulk and coated materials developed at CERN for different beam collimation functionalities. Manufacturing of these materials was then passed to the industry, leading to a series production for use in the collimators installed in...
Beam-induced heating of equipment can have several undesirable effects, including rendering the equipment temporarily inoperative, equipment degradation and/or damage. Hence, to avoid these problems, it can be necessary to limit beam intensity. Beam-coupling impedance mitigation of existing devices and/or design optimization of new accelerator elements are essentials to overcome these...
Beam-ion instabilities belong to a broader class of two-beam instabilities caused by the interaction of a primary beam (electron or hadron bunches) with a secondary beam (ion or electron cloud). The transverse oscillations of these beams can couple with each other. Their amplitude will grow, leading to beam losses. These instabilities can limit the operation of fourth-generation light sources...
Laser-plasma electron beams are known for their large divergence and energy spread while having ultra-short bunches, which differentiate them from standard RF accelerated beams.
To study the laser-plasma beam dynamics and to design a transport line, simulations with CODAL [1], a code developed by SOLEIL in collaboration with IJCLab, have been used. CODAL is a 6D 'kick' tracking code based...
The Upgrade from the third to the fourth-generation light source of the SOLEIL synchrotron requires significant work on the reorganization of the equipment in the storage ring. Higher performance such as low emittance, small transverse size and high brightness are expected but requires redesigning the lattice. New constraints appear, requiring innovative designs of insertion device (ID) in...
The advanced storage ring light source needs to realize ultra-low emissivity beam operation, and improving the Touschek lifetime puts forward higher requirements for the performance of RF cavity. In this paper, a novel bimodal normal conducting RF cavity is proposed. In one cavity, two power sources will be connected at the same time to realize the simultaneous operation of the two...
Linear coupling in storage rings mixes horizontal and vertical beam motion. This is similar to the mixing of states in an atomic two-level system by a resonant laser interaction or the mixing of the two states of any spin-½ particle in static and dynamic external magnetic fields like, for example, in nuclear magnetic resonance, NMR, measurements. These coupled two-level systems are usually...
The Rapid Cycling Synchrotron is the key part of the China Spallation Neutron Source with the repetion rate of 25Hz. The lattice of the RCS is based on triplet cells with the superperiod of four. Due to ultilizing the trim quadrupoles in June 2021, the BPM OffSets were carefully measured, and the beam operation is more steady. In this paper, we will review the preparation of BPM OffSets...
A common feature in the design of low-emittance lattices is the small momentum compaction, which implies a short nominal equilibrium bunch length. A short bunch length can lead to beam-induced heating of the storage ring vacuum components, and, combined with the small transverse emittances, can degrade the beam quality and pose severe limitations on the beam lifetime. To mitigate the...
The description of coupling phenomena in electron storage rings is extended beyond the very common formula based on the coupled Hamiltonian [1] into the region where the small coupling is in competition with damping and diffusion from synchrotron radiation. In the derivation, the moment mapping approach is used in combination with the simplified simulation of radiation effects introduced by...
The upcoming Jefferson Lab K-Long experiment at Hall D will require unique beam conditions with a much lower bunch repetition rate and atypically high bunch charge. To optimize the Continuous Electron Beam Accelerator Facility (CEBAF) injector for this experiment, we performed Multi-Objective Genetic Optimization (MGO) using General Particle Tracer (GPT) to determine the magnetic elements and...
CERN-MEDICIS is an isotope mass separation facility for biomedical R&D located in a class A laboratory, receiving up to 50% of the 1.4GeV PSB protons. It was commissioned with radioactive ion beams in 2017. MEDICIS has operated for the past 5 years in batch mode, with targets irradiated in a dedicated beam dump station at HRS, and with external sources provided by cyclotrons and nuclear...
The Future Circular Collider (FCC) study is developing designs for a new research infrastructure to host the next generation of higher performance particle colliders to extend the research currently being conducted at the Large Hadron Collider (LHC) once the High-Luminosity phase (HL-LHC) reaches its conclusion around 2040. CERN’s Integration Office aims to fulfil the requirements of different...
Over recent years four dedicated facilities have been built at Daresbury Laboratory by a team working on thin film SRF cavities. Firstly, a conventional DC resistance facility allows measurements of critical temperature and residual resistance ratio. In addition, three other facilities were designed in house to address superconducting thin film (STF) characterisation specific to cavities. In a...
Measurement of hadron beam emittances with very high dynamic range, one part-per-million and above, become available recently. This level of dynamic range is required for studying the origin and evolution of the halo in high intensity hadron linacs. There are no established or commonly known metrics to describe such distributions. Using data from the emittance measurements of 2.5Mev H- beam at...
The insertion device for FAXTOR, the new hard XR tomography beamline at ALBA, is a 54mm-period in-vacuum wiggler. The device is of hybrid PM-type, consists of 11 poles for a total magnetic length of 362mm, and it will operate at a minimum mechanical gap of 5mm. The device has been manufactured by AVS Company. During the manufacturing process, the field quality of each individual magnetic...
In this paper, the dynamic response measurement of fast corrector at the High Energy Photon Source (HEPS) is reported. The measurement system for the fast corrector of the HEPS is based on a flat coil with high cut-off frequency. Both amplitude-frequency response and step response are measured. The measurement results indicate that the open-loop bandwidth of the fast corrector is higher than 5 kHz.
In the framework of the High Luminosity Upgrade of the LHC (HL-LHC) the beam intensity from the injectors must be doubled while keeping longitudinal beam parameters unchanged. As such, high-quality beams with high intensities are required also from the Proton Synchrotron (PS). The beam coupling impedance plays a crucial role and mitigation measures must be taken to remain within a stringent...
Following the successful implementation of the LHC Injectors Upgrade (LIU) project, the CERN injectors were re-commissioned in 2021 and have been delivering beam to the LHC since 2022. The operationally delivered beam is well within the specifications regarding its brightness. However, heavy population of non-Gaussian tails of the transverse beam profiles were observed.
These tails lead to...
Neural network (NN) has been tentatively combined into multi-objective genetic algorithms (MOGAs) to solve the optimization problems in physics. However, the computationally complex physical evaluations and limited computing resources always cause the unsatisfied size of training set, which further result in the combined algorithms handling strict constraints ineffectively. Here, the...
A 1.2-m-long superconducting wiggler with the peak field of 4.3 T and period length of 70 mm has been recently installed for the High energy Engineering X-ray (HEX) Diffraction beamline at Cell 27 of NSLS-II Storage Ring. The commissioning result for the orbit feedforward system will be presented, including the uncorrectable dispersive pattern in horizontal orbit and non-negligible hysteresis...
HZB has completed the commissioning of SupraLab, a complete cavity processing and testing facility. It has been used to recover several superconducting cavities for different accelerators. This article describes all the tested and validated steps from cavity processing to cold rf test and module assembly. They include approved filed-emission free cleanroom work, on-site chemical processing,...
The RF Accelerator Research Division at SLAC is developing fully integrated linear accelerator systems for low energy applications, with a smaller footprint and higher efficiency than facility-scale accelerators. These systems are packaged as single units that include the high voltage power supply, RF sources, controls, and the linac structure itself. A considerable part of the effort is in...
The Iranian Light Source Facility (ILSF) is in the detailed design phase. It will operate at 3 GeV and 400 mA with an ultra-low horizontal emittance of 0.27 nm. rad. The main storage ring combined dipole magnet has a 0.56 T magnetic field and a -7 T/m gradient. It can serve as a soft X-ray source, and there are several ways to achieve hard X-rays; one is to use a high-field dipole. It is...
The standard injection scheme of ILSF is composed of 2 septum and 4 kicker magnets installed in a 7-meter-long straight section. Further tuning of the 4 kicker devices to reduce perturbations has proven to be almost impossible since it requires having 4 identical magnets, electronics, and Ti-coated ceramic chambers. Different from pulsed dipole kicker magnets used in a conventional local-bump...
The Spallation Neutron Source (SNS) Radiofrequency (RF) Systems have operated at over 98.5 percent availability for the last several operational periods. The implementation of a more stringent goal for the SNS RF – to exceed 99 percent availability – coupled with the more general desire to increase reliability for accelerator-driven systems has required a more subtle approach to reducing...
It took a decade to develop the 500-MHz module for the Solid State Power Amplifier (SSPA) in NSRRC. Performance of a single module was gradually improved to reach a steady output power of 960W by using the RF chip IC-BLF578XR. Heat dissipation unit and high-efficiency power supply are key issues in improving integral performance (49.5% RF power) of the single module. A 110-module SSPA tower...
The PETRA IV upgrade project is aiming at building a 6 GeV diffraction-limited light source. The storage ring’s off-axis accumulation injection scheme will allow generating a wide range of filling patterns for the needs of photon science users. To preserve high beam quality and low transverse emittances it is imperative to ensure beam stability against collective effects. In this paper we...
We present a theory of coupled-bunch longitudinal instabilities for storage rings that employ a harmonic cavity to lengthen the bunch. We find growth rates associated with the m=0 and m=1 modes for both "optimally" and "overstretched" bunches; the former is a Robinson-like instability, while the latter corresponds to the "periodic transient beam loading" effect described in Ref *. By...
A promising approach for compact linear accelerators in the THz frequency range is based on dielectric-loaded waveguides (DLWs). Higher breakdown fields expected at THz frequencies should enable higher acceleration gradients. However, the accelerating mode of a cylindrical DLW (TM01) is not the fundamental and only mode inside the waveguide at operating frequency. Therefore, a...
For the upgrade of the 6 GeV synchrotron light source PETRA III into a diffraction-limited storage ring PETRA IV it is planned to replace the 23 m long double-bend achromats by hybrid six-bend achromats (H6BA). The high packing density of elements in the H6BA cells requires that the distance between magnets are small with only a few centimeters between the yokes for some of the magnets....
NHa and IBA are collaborating to develop a new cyclotron dedicated to hadron therapy.
This cyclotron is based on two symmetric NbTi superconducting coils, cooled at 4,3 K in helium bath. The cold mass is 15 tons, the diameter of the cryostat is about 5 meters. 470 liters of liquid helium are cooled by cryocoolers, and the coils are maintained at superconducting temperature by using a...
Significant developments in the future of linear accelerators including the operation of high gradient cavities, novel cathodes, and improved magnet designed are enabled by cryogenic operation of various subsystems and components. In order to address the growing needs of traditional infrastructure operating in a new low temperature regime, we have commissioning infrastructure for the testing...
Minimizing projected emittance of high brightness electron beam is important for efficient overlap between electron beam and radiation pulse in an FEL facility. Coherent synchrotron radiation (CSR) emission in a single bending section in the beam transport system usually introduces different slice energy modulation hence different slice transverse kicks in the designed dispersion-free lattice,...
As various experimental reactors in Europe are already
or will be decommissioned over the next years, new neutron
sources will be necessary to meet the demand for neutrons
in research and development. The High Brilliance Neutron
Source is an accelerator driven neutron source planned at the
Forschungszentrum Jülich. The accelerator will accelerate
a proton beam up to an end energy of 70...
Korea-4GSR is a greenfield electron storage ring with circumference of 800 m and natural emittance of 60 pm. Preliminary conceptual lattice design of Korea-4GSR is fully periodic 28-cell H7BA. By keeping the conceptual design as much as possible, we have been exploring modification on the design for higher brightness and better nonlinear properties such as dynamic aperture and Touschek...
The damage mechanisms and limits of superconducting accelerator magnets caused by the impact of high-intensity particle beams have been the subject of extensive studies at CERN in the recent years. Recently, an experiment with dedicated racetrack coils made of Nb-Ti and Nb3Sn strands was performed in CERN’s HiRadMat facility. In this paper, the design and construction of the sample coils as...
Particle accelerators and light sources are some of the largest, most data intensive, and most complex scientific systems. The connections and relations between machine subsystems are complicated and often nonlinear with system dynamics involving large parameter spaces that evolve over multiple relevant time scales and accelerator systems.
Data Intensive Science offers exciting prospects...
We have designed and fabricated a new DC septum magnet for modern accelerators. Septum magnets feature a dipole magnetic field deflecting designated beams at one side of the septum while providing no deflecting field on the other side. Conventional direct-drive type DC septa is embedded with coils inside the magnet gap, which usually results in rather high current density in the thinner septum...
Recently, a double-double bend achromat (DDBA) lattice is designed for Hefei Light Source (HLS), a second-generation synchrotron radiation light source, which reduced the natural emittance a lot. In this paper, to further reduce the emittance and improve the brightness, a DDBA-hybrid 6BA lattice is proposed and applied to the design for the potential HLS upgrade. With more bending magnets, the...
In Particle accelerators, commissioning of a complex beam line requires extensive use of computer models. When the as-built beam line cannot be exactly modeled by the simulation (due for example to mechanical errors or to the extensive usage of the non-linear focusing forces), the solution found in the simulations needs to be adjusted. Thus, it is often required to modify the settings by...
We describe an experiment to demonstrate Derbenev’s flat-to-round (FTR) and round-to-flat (RTF) optical transformations*, designed to match electron beams from a high-energy storage ring into and out of a solenoidal cooling channel. We are using a linear transport system with a design optimized by a computationally-efficient adjoint moment equation technique developed by our group for general...
Expressions to quantify betatron mismatch and chromatic effects are frequently used in accelerator physics, but their derivations are not given in standard text books, making their interpretation difficult. First parameters describing betatron mismatch are introduced using normalization with respect to reference Twiss parameters describing a lattice. In a second step, the derivatives of these...
Synchrotron light sources of the 4th generation typically use varying radius dipoles (also called longitudinal gradient bends). The longitudinal variation of these magnets needs to be properly modeled as the preconditions of the common local 2D approximation are only fulfilled at certain places.
We describe our concept of modelling such magnets using basis functions (approximately)...
Cornell is designing a standalone superconducting radio-frequency (SRF) accelerating cryomodule which utilizes a conduction cooling scheme in place of liquid helium. A key component of this system is a new single-cell 1.3 GHz Nb$_3$Sn-coated SRF cavity. This cavity was designed based on Cornell’s ERL injector cavities in order to replicate their RF properties, such as being able to operate at...
In 2018, an Advanced Electron Test Facility, named Dalian Advanced Light Source (Pre-research) was proposed and approved, which consists of an electron source, two cryomodules based on superconducting technology, a Transverse Deflecting Structure (TDS) system, and beam dumps. As an eminently practical instrument, TDSs are used for longitudinal and transverse phase-space analysis in Free...
Multi-objective evolutionary algorithms (MOEAs) are usually used to optimize two or three objectives in the accelerator field and perform well. However, the optimization objectives are often equal to or greater than four for an accelerator, which causes severe deterioration of the performance of these algorithms. Recently, many-objective evolutionary algorithms (MaOEAs) that can solve the...
In this paper we present the design and validation of a compact LEBT for the LINAC 7 project. Specifically, the LINAC 7 project focuses on building a new generation, low-energy, low-current compact accelerator. The core idea is to achieve an energy of 7 MeV in less than 12 m while maintaining enough current to generate isotopes for medical uses.
Through this work we explain the procedure we...
Transverse deflecting cavity (TDC) providing time-dependent kick with fixed polarization is an important tool for beam diagnostics and manipulation. Recently, several types of novel TDC with variable polarization have been developed to fulfill the requirements of multi-dimensional phase space measurement of high-quality electron beam as well as fast scanning in proton therapy. Based on the...
The Hefei Advanced Light Facility (HALF) is a future soft X-ray diffraction-limited storage ring at National Synchrotron Radiation Laboratory (NSRL), which aims to decrease the horizontal emittance to improve the brilliance and coherence of the soft X-ray beams. The lattice of the ring depends on the use of many short and high field multipole magnets, dipole-quadrupole magnets with high...
The PETRA IV storage ring is a project planned to upgrade the synchrotron light source PETRA III at DESY. The main aim is to decrease the horizontal emittance as low as 20 pmrad. This nominal emittance will be achieved by a hybrid six bend achromat lattice (H6BA) and a series of damping wigglers. The magnets used in this lattice will be a combination of resistive quadrupole and higher...
The Lanzhou Light Ion Cancer Therapy Facility (LLICTF) is a compact medical accelerator currently under construction. It is designed to treat cancer using a 230MeV, 30mA H+ beam and a 85MeV/u, 1mA 3He2+ beam. The facility comprises two ion sources, a low-energy beam-transport (LEBT), a Radio Frequency Quadrupole (RFQ), a medium-energy beam-transport (MEBT), and the main ring accelerating...
This paper describes the design progress of the electron gun, and solenoid of 50 MW class klystron at C-band frequency (5720 MHz) for CEPC LINAC. The beam optics is designed in DGUN code for a space charge beam current of 318 A at an acceleration potential of 350 kV with average cathode loading of less than 6.0 A/cm^2. The maximum surface electric field at the beam optics and high voltage...
For an experimental setup at the laser plasma accelerator (LPA) at the JETi Laser at Jena, Germany, an energy upgrade of a linear beam transport line has been studied. The transport line, originally designed to match the LPA beam to a transverse gradient undulator (TGU) at 120 MeV and successfully experimentally tested in 2014, will be upgraded to up to 300 MeV by employing stronger focusing...
The investigation of the processes, materials, technology and welding procedures used to manufacture accelerating components for maximum accelerating gradient (>100 MV/m) and minimum RF breakdown probability has led us to the proposal of hard-copper structures in Ka-Band made of multiple parts.
In this paper, we illustrate the TIG welding tests, including visual inspection and temperature...
In order to provide hard X-rays with a 1.5 GeV electron ring, a new superbend-magnet will be used in the middle of each standard cell at Wuhan Advanced Light Source (WALS). The design, assembly, and detailed magnetic measurement of the superbend-magnet prototype has been finished. It is a three-stage combined magnet, with a high-field permanent magnet in the middle and two low-field...
We image the five-dimensional phase space distribution of a hadron beam in unprecedented detail. The resolution and dynamic range of the measurement are sufficient to resolve sharp, high-dimensional features in low-density regions of phase space. We develop several visualization techniques, including non-planar slicing, to facilitate the identification and analysis of such features. We use...
The Future Circular Collider (FCC) study develops the technologies for next generation high performance particle colliders and accelerating structures. It places high requirements on the performance of Superconducting Radio Frequency (SRF) cavities used to accelerate the particle beam. While niobium-coated copper cavities are being considered for FCC-ee, alternative superconducting materials...
The radio frequency system of High Energy Photon Source adopts a double-frequency design with a main frequency of 166.6 MHz and a third harmonic frequency of 499.8 MHz. There are six normal-conducting cavities on the booster, and each cavity will be driven by a 500-MHz 100-kW solid-state amplifier (SSA) with high modularity, high efficiency and sufficient redundancy. Five 166.6-MHz and two...
Since its operation in 2013, Taiwan Photon Source (TPS) has been constantly maintaining and developing new technologies to improve its power electronics systems. The availability of GaN FETs power devices with integrated drivers and protection functions has allowed designers to achieve new levels of power density and efficiency in these systems. This paper explains how to use GaN FETs for...
The extraction system of the superconducting AGOR cyclotron consists of an electrostatic deflector and three electromagnetic channels. As the electrostatic deflector has only a moderate field strength (<100 kV/cm), the first electromagnetic channel has to generate a rather strong dipole component resulting in current densities up to 169 A/mm^2 in water-cooled copper coils.
In the original...
The invention relates to a special power supply for injection of a compact electronic storage ring and an injection method, belonging to the technical field of special power supply for particle accelerators. The power supply includes a DC power module, a switching power module, a high-frequency resonant capacitor and a control circuit. The invention adopts the series resonance scheme, drives...
Lens based proton radiography is a powerful diagnostics technique capable of resolving ultra-fast processes on the ns-scale in dense matter with unprecedented micrometer spatial resolution. This unique performance is currently realized by the use of a chromatic imaging system consisting of four quadrupole magnets that are configured to suppress the most significant 2nd order position dependent...
An air-core pulsed magnet named Ceramics chamber with integrated Pulsed Magnet (CCiPM) was developed as a fast dipole kicker at first. A prototype of a dipole CCiPM was designed and tested successfully at KEK Photon Factory (KEK-PF). Because of the feature of an air-core magnet, a CCiPM can also generate an octupole magnetic field for pulsed multipole magnet injection. Compared with the pulsed...
The injector of Hefei Advanced Light source Facility (HALF) will choose the full energy injection method with beam energy up to 2.2 GeV by a LINAC, which will contain 40 S-band normal conducting traveling wave tubes. Quasi-symmetric single-feed racetrack couplers were used in design of TW tube utilized for reduction the field asymmetry inside the coupler cavity. The design and test result of...
After 20 years of use, the Hall-probe system at the Na-tional Synchrotron Radiation Research Center (NSRRC) has poor measurement reproducibility. The granite bench is 6m long and is robust but the Hall-probe stage with air bearings has deteriorated. To create a reasonable operat-ing space for field correction for an insertion device (ID), the distance between the ID and the measurement system...
SLAC has been developing the parallel finite element electromagnetics simulation suite ACE3P (Advanced Computational Electromagnetics 3D Parallel) for accelerator modeling using high performance computing (HPC) platforms. ACE3P employs the parallel high-order finite-element method with conformal (tetrahedral) mesh for high-fidelity representation of geometry, and further accuracy can be...
An RF Fundamental Power Coupler(FPC) designed to operate under 7 kW CW for 325 MHz superconducting(SC) single spoke resonator(SSR) in the high energy SC Linac of the RAON. A prototype FPC has a coaxial shape with an impedance of 98 ohm and an outer radius of 36 mm. It is checked that the MP exists within the SSR operating range. Reduction or elimination of the MP is estimated applying DC...
Permanent Magnet (PM) based bending magnets are state-of-the-art concepts to gain stable beam operation and to reduce the power consumption of the magnetic system in an accelerator. This is even more true in injector and beam transport beamlines with fixed beam parameters and low repetition rates. An example is the B2PT magnet in the BESSYII transfer beamline between booster and storage ring....
The Advanced Light Source Upgrade (ALS-U) project at Lawrence Berkeley National Laboratory (LBNL) is major upgrade of the ALS that involves the design and installation of a new Accumulator Ring and an upgraded Storage Ring. The RF High Power Amplifier (HPA) with 60 kW CW output power at 500 MHz is a complex and very costly piece of equipment that will provide high power RF to the accelerating...
Coherent Synchrotron Radiation (CSR) is regarded as one of the most important reasons that limits beam brightness in modern accelerators. Current numerical packages containing CSR wake fields generally use 1D models, which can become invalid in extreme compression regime. On the other hand, the existing 2D or 3D codes are often slow. Here we report a novel particle tracking codes --- DFCSR ---...
Dielectric Assist Accelerating (DAA) structures based on ultralow-loss ceramic are being studied as an alternative to conventional disk-loaded copper cavities. This accelerating structure consists of dielectric disks with irises arranged periodically in metallic structures working under the TM02-π mode.
Here, the numerical design of an S-band DAA structure for low beta particles, such as...
Particle accelerators require extensive optics measurement and correction. Due to the complexity of analytic treatments, numerical optimizations are often employed. A disadvantage of this approach is the lack of gradients, limiting optimization methods to derivative-free ones such as simplex or genetic algorithms. We explore a reformulation of beam optics that preserves gradient information by...
As multipurpose synchrotron radiation facilities, the Korea-4GSR is being promoted in Korea from July 2021 to the end of 2027. The construction project includes linac, 4 GeV booster, and storage ring. The circumference of the storage ring is about 800 meters, the beam emittance is 58 pm.rad, and there are more than 40 beamlines with 28 superperiods. A large number of electromagnets are used in...
An algorithm for determining the eigenvalues of the eigenfunctions of a
multilayer cylindrical waveguide is constructed. A relationship is found
between dispersion relations and impedances. A method for determining
the resonant frequencies of the wake field in the linear and helical
motion of a particle is described. The damping coefficients of
eigenmodes at resonant frequencies are determined.
The calculation of the volume of the phase-space stability region of hadron storage rings is currently performed through computer simulations of particles tracking in 6D coordinates, which are resource -and time- intensive processes. We have investigated in a previous paper the ability of an ensemble reservoir computing approach based on Echo State Networks to predict the long-term evolution...
Dynamic Aperture (DA) studies based on single-particle tracking simulations have proven to be a powerful tool for optimizing the performance of the Large Hadron Collider (LHC), as well as its future High-Luminosity upgrade (HL-LHC). The present paper presents the studies performed for the first year of HL-LHC operation at the beginning of the fourth operational run of the LHC. The main focus...
The design and tuning of accelerators are both complicated processes involving many physical effects. Of these, the modeling of coherent synchrotron radiation has long been one of the most complicated and time consuming. This is especially true when modeling two and three-dimensional CSR, which is often neglected in state-of-the-art accelerator modeling due to its time consuming nature. We...
Solid-state RF amplifiers (SSAs) are being developed to compose SIRIUS storage ring’s RF plant for operation with superconducting cavities. Each amplifier must deliver up to 65 kW of RF power at 500 MHz and a high AC-to-RF efficiency is desired to minimize operation costs. To this end, amplifier modules able to deliver 900 W with approximately 70 % DC-to-RF efficiency were designed. To combine...
The EIC Crab Cavity Low-Level Radio Frequency system will have to regulate the crabbing and uncrabbing voltages, while also keeping their sum close to zero. The system will have to reduce the crab cavity impedance to prevent transverse instabilities. It will also have to maintain extremely low RF noise levels injected to the beam. This work presents an estimate of the required performance for...
The electrodeposition of copper onto niobium using commercial acidic and alkaline electrolytes was tested. The continuous dense polycrystalline copper films were successfully obtained in aqueous alkaline-type bath containing copper sulphate, sodium hydroxide and sodium gluconate. The effect of benzotriazole and sodi-um lauryl sulphate additives on the morphology and crystal structure of the...
X-ray flash radiography is a powerful diagnostic used worldwide for investigating the structural response of matter under impulsive loading during hydrodynamic experiments. These experiments require a specific X-Ray source generated by a Linear Induction Accelerator (LIA). LIAs produce an intense electron pulsed beam, with a high-energy and providing a high dose at 1 m. Therefore,...
The Future Circular Collider (FCC) study is developing designs for a new research infrastructure to host the next generation of higher performance particle colliders to extend the research currently being conducted at CERN. In particular, FCC-ee is an electron-positron collider, which is the first stage towards a 100 TeV proton-proton collider FCC-hh.
FCC-ee may be affected by electron cloud...
Fermilab Booster synchrotron requires an intensity upgrade from 4.5×1012 to 6.5×1012 protons per pulse as a part of Fermilab’s Proton Improvement Plan-II (PIP-II). One of the factors which may limit the high-intensity performance is the fast transverse instabilities caused by electron cloud effects. According to the experience in the Recycler, the electron cloud gradually builds up over...
When operated with the nominal bunch spacing of 25 ns, the Large Hadron Collider (LHC) suffers from significant electron cloud effects. During the second operational run (Run 2) of the LHC, beam-induced conditioning allowed a satisfactory exploitation of 25 ns beams for luminosity production but could not fully suppress electron cloud formation. It has since been understood that this...
Optical Stochastic Cooling (OSC) is a feedback beam cooling technique that uses radiation produced by a beam to correct particles' own momentum deviation. This system is made up of two undulator magnets, the pickup and kicker, separated by a bypass chicane that introduces a momentum-dependent path length. The beam produces radiation in the pickup and arrives in the kicker with a delay...
Elettra 2.0 is the Project finalized to upgrade the Storage Ring (SR) and part of the beamlines (BLs) of Elettra. The machine optics requires a significant number of magnets and additional coils to energize individually. More than 1200 DC power converters (PCs) are foreseen. A synergic design of the magnets and the associated PCs led to a great standardization: four current ranges (300 A, 100...
A simple acceleration of a high charge, needle-shaped electron bunch from a cathode is affected by strong correlated emittance growth due to current-dependent transverse space-charge forces. It was shown that such emittance growth could be reversed by focusing the bunch soon after it emerges from the cathode, and that one can expect to retrieve the emittance the beam was born with – the...
The exchange of transverse and longitudinal emittances is a unique feature of emittance exchange (EEX) beamline, but it is also a limitation of it at the same time. Most of the modern high-brightness injectors provide much smaller emittance in the transverse plane than the longitudinal plane. Thus, a beam passing through a single EEX beamline ends up with a large transverse emittance, which...
A crucial common parameter for the new 4th generation machines is the reduced dynamic aperture at injection point.
Will be presented the analyzed strategies and what have already been done in order to reduce the emittance of the injected beam and garantee a good injection efficiency.
Limited dynamic aperture which is in the consequence of strong nonlinearities in a low emittance storage ring, is a challenging issue from beam dynamics point of view. In the present study, we have applied three families of focusing and defocusing octupoles to the storage ring lattice with the aim of increasing dynamic aperture and beam lifetime . We have discussed different methods to...
An experiment to study damage caused by the impact of 440 GeV/c protons on sample superconducting racetrack coils made from NbTi and Nb3Sn strands was recently carried out at CERN's HiRadMat facility. This paper reports on the detailed Monte Carlo simulations performed with FLUKA and Geant4 to evaluate the energy deposition of the 440 GeV/c proton beam on the sample coils positioned in the...
Hefei Advanced Light Facility (HALF) is a fourth-generation storage ring with an emittance lower than 100 pm∙rad. To assess the real performance, in this paper, static error effects are studied and corrected for HALF. Simulation corrections of closed orbit, linear optics and transverse coupling are presented and the results show that the HALF lattice has reasonable robustness. The emittance...
We describe here field emission measurements set-up, diagnostics tools used, analysis and results developed for ESS medium and high beta cryomodules tests . For high gradient, in particular, field emission can be the mechanism which limits cavities performances. A particualar focus will be given to analysis tools developed to tack potential materials activation, due to high energy photons...
The European Spallation Source (ESS) will accelerate a beam of protons with a beam pulse width 2.86ms long and pulse repetition frequency 14Hz. The acceleration will be provided by 155 cavities, out of which 97% of the cavities are superconducting.
The first section of the ESS superconducting linac is the Spoke linac. The spoke linac increases the beam energy from 90MeV to 216MeV using the...
A source for polarized positron beams at the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab is being designed. The Polarized Electrons for Polarized Positrons (PEPPo) concept is used to produce polarized e$^+$e$^-$-pairs from the bremsstrahlung radiation of a longitudinally polarized electron beam interacting within a high-Z conversion target. The scheme under...
The beam screen for the Future Circular hadron-hadron Collider (FCC-hh) has a baseline design based on a copper (Cu) coating. Calculations have indicated that the resistive wall impedance will be the major contributor to the beam impedance for the FCC-hh at both injection and collision and that Cu might be on the limit to ensure beam stability. To increase the safety margin, it is desirable to...
We present the results of the first experiments on 4-dimensional phase-space tracking of a single electron in a storage ring, using a linear multi-anode photomultiplier tube for simultaneously measuring transverse coordinates and arrival times of synchrotron-radiation pulses. During the next few months, full 6D tracking will be implemented. This technology makes it possible to characterize the...
Merging beams from multiple beamlines is critical to energy-recovering linear accelerators and beam-driven wakefield accelerators. Recently, a "straight-merger" beam line was proposed as a compact beamline to merge beams. The concept is based on a deflecting cavity with a superimposed dipole field. It provides a large deflecting kick at the injection phase where the RF and magnetic kicks add...
Experimental beamlines often are regularly reconfigured to meet changing requirements of the experiments and to minimize beam losses. The configuration is usually done with the help of beam optics tools like MADX. These tools offer matching capabilities which allow to find solutions in terms of quadrupole strengths. However, such solutions are found by satisfying the given constraints only and...
The beam dynamics of a bunch both longitudinally and transversely play a major role in the design process of an RF cavity, from the feasibility of cavity lengths, to the focusing schemes required to maximise capture. Often, computer simulations track particles using computationally intensive numerical techniques, which can be extremely time-consuming to run. In this paper, we present a...
Many accelerators employ axisymmetric structures, such as RF cavities, induction cells, and solenoids, to accelerate and transport charged particle beams. To analyze the motion of the beam in solenoids, it is common to make a transformation to the rotating Larmor frame. In the presence of an electric field, this transformation can be modified to obtain further simplifications in the equation...
The new fourth-generation synchrotron radiation source PETRA IV at DESY (Hamburg) will use a fast orbit feedback system to meet stringent orbit stability requirements. To this end, hundreds of fast orbit corrector magnets will be installed to minimize orbit distortions from external sources. These magnets are operated at high frequencies, creating strong eddy currents that result in Joule...
Upcoming projects requiring ~650 MHz medium-to-high-beta elliptical cavities such as Michigan State University’s Facility for Rare Isotope Beams’ energy upgrade and Fermilab’s Proton Improvement Project-II drive a need to understand magnetic RF loss mechanisms in greater detail. It remains to be seen whether flux trapping mitigation techniques used in 1.3 GHz cavities are as effective at ~650...
A higher-order-mode-damped 166.6 MHz beta=1 quarter-wave superconducting cavity is being developed for the High Energy Photon Source. The frequency variation of the cavity in all the processes comprising of manufacturing, post-processing and cooldown to 4.2 K, should be strictly controlled due to the relatively small coarse tuning range. The step-by-step evolution of the cavity frequency was...
In the lattice design of the BESSY II successor, the diffraction-limited, Multi-Bend-Achromat (MBA) storage ring BESSY III, HZB follows the approach of deterministic lattice design. MBA lattices are composed of rather simple sub-structures: the repetitive unit cell, two dispersion suppression cells at the end of the achromatic section, and the focusing doublet or triplet with the straight...
This paper is the follow-up of a previous one where we reported symmetry breaking as the main factor that establishes transverse resonance island buckets (TRIBs) close to a third-order random resonance in one of BESSY III design lattices by using a single knob. Here we present a more complete picture of the analytical framework and we show that there are two types of resonances close to which...
Field emission (FE) is one of the main reasons for the degradation of superconducting cavity quality factor. Its presence can limit the ultimate performances of superconducting RF (SRF) cavities and hence the cryomodule in which they are assembled.
For these reasons, it is essential to better understand how this phenomenon is generated and evolves from the SRF cavity preparation, in the...
Corrugated structures have been used widely in X-ray free-electron laser facilities for chirp control, fresh-slice applications, and diagnostics. In this paper, we present a general method for calculating the short-bunch wakefield of corrugated structures with arbitrary shapes. At zeroth order, we give analytical solutions via the method of conformal mapping. At first order, we give...
The Generalized Gradient (GG) formalism of Venturini and Dragt for describing static magnetic or electric fields has been implemented in the Bmad toolkit for accelerator simulations. In conjunction with this, a new method for calculating GG derivatives from a field table has been developed which avoids some of the problems of the Venturini and Dragt method. Generalized gradients are also...
Accurate and efficient particle tracking through Siberian Snakes is crucial to building comprehensive accelerator simulation model. At the Alternating Gradient Synchrotron (AGS) and Relativistic Heavy Ion Collider (RHIC), Siberian Snakes are traditionally modeled in MAD-X by Taylor map matrices generated at specific current and energy configurations. This method falls short during ramping due...
In the radio-frequency system of synchrotron light sources, it is necessary to lengthen the bunches by creating harmonic cavities to improve the beam lifetime. In this paper, we propose three harmonic cavity designs: TM010 mode cavity, TM020 mode cavity, and dual mode cavity, with the Wuhan Advanced Light Source (WALS) as the background. By comparing the beam quality, beam lifetime, and...
The growth rate of the Head-Tail mode 0 instability is related to the real part of the transverse beam coupling impedance. The SPS transverse impedance model, which includes the major impedance contributions in the machine, can be benchmarked through measurements of growth rates as a function of chromaticity. This paper summarizes the methodology established to explore a wider range of...
A solution is presented for the radiation field of a particle moving along
a helical trajectory in a cylindrical waveguide with multilayer walls. The
number of layers and their filling is arbitrary. The solution was obtained
by the partial domain method and is a generalization of the solution for a
resistive waveguide obtained earlier.
The industrial, medical and homeland security markets for low-to-moderate energy electron linacs are growing rapidly, often requiring beam currents that strongly load the accelerating fields. The two-beam accelerator (TBA) is one concept for the structure wakefield acceleration approach to an electron-positron collider. Transient beam loading effects are a significant challenge for the drive...
J-PARC MR is a high intensity synchrotron that accelerates protons from 3 GeV to 30 GeV. In MR, beam study for 1.3 MW upgrade plan is now in progress. The upgrade is done by shortening the repetition period and increasing the number of protons, and it is crucial to understand their effects on beam motion. Especially, the betatron function is one of the most important parameters that determines...
Pulsed electron beams probe the dynamics of matter out of equilibrium with high spatial and temporal resolution. Ultrafast electron diffraction in particular is sensitive to sub-angstrom, sub-picosecond scale atomic motion. To collect all the structural information available in an electron diffraction pattern, the experimentalist must control the angular magnification onto the detector plane....
This paper presents the magnetic design, mechanical design and assembly tooling design for four 500T/m Hybrid Halbach Quadrupoles with an aperture radius of 4mm. The quadrupoles will be used for capture of a 1-5 GeV electron beam produced in a plasma acceleration stage at the Extreme Photonics Application Centre which is currently under construction at Rutherford Appleton Laboratory in the...
We developed high-precision digital control magnet power supplies (MPSs) aiming at next-generation light sources such as SPring-8-II. The system consists of a high-precision ADC circuit and an FPGA that processes a proportional-integral control and pulse-width-modulation. Using the system, the current ripple and long-term stability (8 hours) of the MPS are controlled within 20 ppm. The MPS can...
A new 1.3 GHz solid-state high-power RF amplifier (SSA) has been built for the Lighthouse project in close cooperation between Cryoelectra and RI Research Instruments. The amplifier was developed by Cryoelectra as a scalable compact system with an RF-power density of 40 kW/m². Its industrial design is very reliable and easy to maintain. The SSA delivers a continuous RF output power of more...
MedAustron is a synchrotron-based ion therapy center in Wiener Neustadt, Austria, constantly working towards the performance improvement of cancer treatment. A major improvement opportunity comes from the scanning magnets system – a crucial element of dose delivery system at MedAustron - that is influenced by the bandwidth and power density of the magnet power supplies. Therefore, a novel...
A superconducting (SC) 1.5 GHz (3rd harmonic) cavity is being developed for lengthening bunch and improving beam lifetime in the Hefei Advanced Light Facility (HALF) storage ring.This SC cavity is excited by an electron beam with 350 mA current, 1 nC charge, and ~6.7 ps length and requires strong damping of higher-order-modes (HOMs) in order to meet beam instability requirements. Two fluted...
Current and historic tracking studies of the RHIC accelerator lattice find difficulty in explaining the transmission efficiency of spin polarization from the AGS extraction to
RHIC storage energies. In this paper, we discuss mechanisms that result in resonant depolarizing behavior, beyond the usual intrinsic and imperfection resonance structures. In particular, the focus of this paper will be...
Cryoelectra’s 3rd generation of solid-state RF amplifiers (SSA) for synchrotron applications is presented in the frame of a poster. The SSA delivers up to 160 kW cw RF output power at 500 MHz. The amplifier is of industrial design regarding space and maintenance requirements. Together with its redundant architecture this allows for a 24/7 operation over several months without any need of...
The MAX IV 100 MHz RF cavities are the main contributors for the 3 GeV storage ring longitudinal coupled bunch instabilities. With the knowledge of strong higher order modes (HOMs) since the design stage of the cavities, extra ports are present for the future HOM dampers. This contribution presents the electromagnetic and mechanical designs and the thermal simulation for the HOM damper...
Two types of crab cavities, one at 197 MHz and the other at 394 MHz, are designed to compensate the loss of luminosity due to a 25 mrad crossing angle at the interaction point (IR) in the Electron Ion Collider (EIC). The Higher Order Mode (HOM) damper designs of the EIC differs from the LHC designs since in the EIC the impedance budget is tighter, especially longitudinally, and in the EIC the...
The heavy-ion accelerator of the Rare Isotope Science Project (RISP) in Korea has been developed. There are three types of SRF cavity, which are 81.25MHz quarter-wave resonator (QWR), 162.5MHz half-wave resonator (HWR), 325MHz single-spoke resonator (SSR). There are 22 QWRs and 102 HWRs in the superconducting linac#3 (SCL3), and 69 SSR1s and 144 SSR2s in the superconducting linac#2 (SCL2). The...
The modeling of current and next-generation particle accelerators is a complex endeavour, ranging from the simulation-guided exploration of advanced lattice elements, over design, to commissioning and operations.
This paper explores hybrid beamline modeling, towards coupling s-based particle-in-cell beam dynamics with machine-learning (ML) surrogate models.
As a first example, we train a...
Crab Cavities (CCs) are a key component for the HL-LHC luminosity upgrade. To significantly reduce the Long-Range Beam-Beam (LRBB) effects a large crossing angle scheme is needed . The installation of 4 CCs per beam in each of the two main interaction points aims to restore the luminosity loss caused by the crossing angle. Noise injected through the Low-Level RF (LLRF) system in these cavities...
The LHC particle-physics program requires that the delivered luminosity be measured to an absolute accuracy in the 1% range. To this effect, the absolute luminosity scale at each interaction point (IP) is calibrated by scanning the beams across each other according to the van der Meer method. During such scans, the orbit and the shape of the colliding bunches are significantly distorted by...
Solid-state power amplifier systems as RF sources for particle accelerator are paving their way into industrial products due to several advantages compared with established tube technology. Within this change a demand for optimized performance as trade off from power gain and efficiency rises to reach the high-power levels and for ensuring an electrical efficient operation. When combining...
This proceeding addresses the effect of the neutral molecules trapped by the beam. It is in particular discussed the effect of a non-uniform neutral molecule distribution on the beam profile and the resulting beam lifetime. According to the trapping temperature it is discussed in a general framework how the beam profile is modified. and the consequent beam loss.
In the presence of a tune spread induced by chromaticity or amplitude detuning, decoherence will lead to the damping of the beam centroid motion after a single transverse excitation. This in turn has implications for the analysis of turn-by-turn based optics measurements, as it affects the precision of the spectral analysis. In the past, it has been shown how the effect of decoherence on...
In order to maintain the continuity of the vacuum system wall and comply with beam stability limits, radio frequency contact bridges are utilised as transitional elements in beam vacuum line interconnections. These radio frequency contact bridges must absorb and correct longitudinal, angular, and transverse misalignments brought on by mechanical motions during assembly, alignment, operating...
Sirius is a 4th generation synchrotron light source at the Brazilian Center for Research in Energy and Materials in Campinas, Brazil. The storage ring is currently operating with a normal conducting seven-cell cavity and an upgrade of the whole RF plant is foreseen to take place in the beginning of 2024. Two CESR-B superconducting cavities will be installed in the storage ring and comb-type...
Impedance modeling is an important subject in diffraction limited storage rings based light sources, due to the adopted small beam pipe as well as the tight requirements from beam collective effects. Therefore, a batch of impedance bench measurements are performed or planned for the dominant impedance contributors in HEPS, including resistive wall impedance of the NEG coated vacuum chambers,...
Recently, the Korean government decided to construct a fourth-generation storage ring (4GSR). Compared to a third-generation storage ring (3GSR), emittance is significantly smaller so that we can achieve higher photon beam brightness. This small emittance enables because of a multi-bend achromat (MBA) which necessitates high magnetic field gradients. Accordingly, the vacuum chamber aperture is...
Impedance-induced tune shifts and instability growth rates in the CERN Proton Synchrotron are studied thanks to the recently updated impedance model of the machine. Calculation of these beam observables are obtained using both Vlasov solvers and macroparticle tracking simulations, and are compared with those observed during dedicated measurement campaigns. Thanks to improvements in the...
Nonlinear integrable optics (NIO) are a promising novel approach at improving the stability of high intensity beams. Implementations of NIO based on specialized magnetic elements are being tested at the Integrable Optics Test Accelerator (IOTA) at Fermilab. One method of verifying proper implementation of these solutions is by measuring the analytic invariants predicted by theory. The initial...
Barrier-Bucket (BB) systems provide a method to apply a short gap to a coasting beam. This is utilized for different applications, like ion cleaning, or to compensate the medium energy loss caused by internal experiments. BB-cavities are broadband cavities, and the applied signal is commonly a short sine burst, followed by a flat section at zero voltage. Since the transfer function of the...
The commissioning of the APS Upgrade storage ring will need to be completed fast in order to minimize the dark time for APS users. To help speed up commissioning, lattice commissioning simulations were developed that allow to test commissioning algorithms and automate the entire process. In this paper, we describe recent improvements and additions to the commissioning simulations. We cover...
RF pulse compressors are used for higher acceleration gradient in the KEK electron positron injector linac. S-band spherical-cavity type pulse compressors (SCPC) with a high quality factor Q of 100,000 have been newly developed, and one of them was installed in the linac. The performance of the compressor is characterized by its cavity parameters such as resonant frequency and Q-value....
As the series production of PIP-II 650 MHz low beta cavities approaches, INFN-LASA R&D activities on cavity prototypes are ongoing. Different surface treatments have been exploited in a joint effort between INFN and FNAL, to establish the series cavity recipe. Meanwhile, the vertical test facility has been upgraded for the test of high-Q cavities, by increasing its capability to reduce the...
It is crucial to have a particle beam with high intensity and small emittance in a timely manner. The main challenges restraining the availability of the beam to the user and limiting the beam intensity in storage rings are a lengthy optimization process, and the injection losses. The setup of the Injection Beam Line (IBL) depends on a large number of configurations in a complex, non-linear,...
Passive superconducting harmonic cavities may cause two types of instabilities when operated in bunch lengthening mode. One is the mode-zero Robinson instability and the other is the periodic transient beam loading instability. In this paper, these two instabilities will be briefly introduced using the parameters of the Hefei Advanced Light Facility storage ring.
Octupole magnets are a central mitigation method against the transverse collective instabilities expected for the high-intensity operation of the SIS18 and SIS100 synchrotrons in the FAIR project. For these beam parameters, the self-field space-charge effect dominates the betatron footprint, and strongly modifies the instability drive and the Landau damping properties. The space-charge tune...
The European Spallation Source (ESS) linear accelerator is designed to accelerate a 62.5 mA, 2.86 ms, 14 Hz proton beam up to 2 GeV for delivery to a rotating tungsten (W) target. The beam transfer sections between linac cryomodules and approaching the target contain over 200 quadrupole, dipole and corrector magnets for beam envelope and trajectory control. In addition, a raster magnet system...
The Radia code is used widely to model magnets for various particle accelerator applications, especially for insertion devices at synchrotron radiation sources. Although Radia provides many useful capabilities, including generally nonlinear relationships between applied fields and material magnetization, it previously lacked a full description of the hysteresis dynamics present in...
The 3rd harmonic cavity is a key component for the 4th generation storage ring. A bunch lengthening by the harmonic cavity increases the Touschek lifetime, which can reduce the emittance in the storage ring. The resonant frequency is selected as 1500 MHz due to the resonant frequency of the main RF cavities being 500 MHz. The prototype cavity is an elliptical double-cell geometry to reduce...
One of the key issues in the technology of superconductors is the protection against quenches. When designing a superconductor as a magnet, a coil or even current leads, the design should be made such that the superconductor withstands all operational conditions as fast discharges, pulsed loads or even rapid transient background fields.
Computational modeling of pulsed-current...
Residual gas atoms, ionized by the electron beam, may create two effects in an electron accelerator. One is the trapping of ions in the beam channel by the Coulomb forces of the beam and the other is the fast beam ion instability, a dynamic mutual transverse oscillation between ions and electrons.
While the strongly reduced beam emittance of the accelerator upgrade SLS 2.0 is helpful in...
Magnetic alloy cavities have been used in many accelerators. We have irradiated small magnetic alloy rings in J-PARC to evaluate radiation effects on magnetic properties. Complex permeabilities and hysteresis curves were measured before and after the irradiation. No significant variation was observed by the total ionization dose of 18 kGy and neutron flux of 2.3$\times10^{14}$ n/cm$^2$. The...
An Injector upgrade at Jefferson Lab presented new requirements for the Wien filter magnets power supplies. In addition to raising the output amperage requirements from 10Amps to 20Amps, the new power supplies are required to drive loads with very low inductance, capacitive effects and stringent ripple limitations. Existing power supply solutions required loads with a minimum of 25mH to...
Korea fourth generation storage ring (Korea-4GSR) is the low emittance storage with an emittance of 61 pm and a circumference of 800 m. The design has been updated to add an injection straight section, where the beta function intentionally made to have high value to relieve the requirement of the off-axis injection. With the injection straight section, the improvement of the injection...
A pulsed electron lens produces a betatron tune shift
along a hadron bunch as a function of the longitudinal coordinates, which is a longitudinal detuning. An example of transverse detuning is the tune shifts due to octupole magnets. This paper considers a pulsed electron lens as a measure to mitigate the head-tail instabilities. A detailed analytical description within a Vlasov formalism...
The design concept of the Electron Ion Collider (EIC), which is under construction at BNL, considers adding a 2nd Interaction Region (IR) and detector to the machine after completion of the present EIC project. Recent progress with development and fabrication of large-aperture high-field magnets based on the Nb3Sn technology for the HL-LHC makes it interesting for using this technology in the...
The synchrotron of XiPAF (Xi'an 200MeV proton application Facility) is a compact proton synchrotron, which can accumulate and accelerate 1e11 particles for 3-order resonance slow extraction, with H^- stripping injection and phase space painting scheme. Now XiPAF is under the challenge of more particle species for single event effect study, like He+, C4+ and so on. This paper report the lattice...
The LHC low-beta quadrupole magnets, also known as “Inner Triplets”, are the final focusing magnets located on each side of the LHC interaction points. The design of the currently operated LHC Inner Triplets is based on NbTi superconducting technology. The magnets are operated in superfluid helium and use a longitudinal heat exchanger to extract the power deposited by the secondary particles...
Proposals to measure a possible Electric Dipole Moment (EDM) of protons in an electro-static machine are studied by a world-wide community. The machine is operated at the so-called magic energy to satisfy the "frozen spin" condition such that, without imperfections and the well-known magnetic moment of the particle, the spin is always oriented parallel or antiparallel to the direction of...
A new accelerator simulation code named Advanced Virtual Accelerator Software (AVAS) was developed by the Institute of Modern Physics, Chinese Academy of Science. Although the code is proposed to simulate the particle transport in the linac of the China Initiative Accelerator Driven System (CiADS), it can be also used for common linacs. The code is based on particle-in-cell (PIC) algorithm and...
At the NSLS-II ring, a 1.2 m long superconducting wig- gler with the maximum 4.34T magnetic field has been in- stalled at a low-β straight section (cell 27) to drive the high energy engineering X-ray scattering (HEX) beamline. To mitigate the potential performance degradation due to the linear optics distortion, a local compensation scheme was adopted and confirmed with the online beam...
Logistics is not "rocket science" nevertheless a poor coordination and planning of procurement, transportation, and storage can cause congestion in the supply and movimentation of components and systems, increasing the risk of delays, damages and - worst of all - injuries to the personnel.
Upgrading an existing machine doubles the difficulties, handling the old parts and the new ones, almost...
The compact STorage ring for Accelerator Research and Technology (cSTART) project aims to store electron bunches of LPA-like beams in a very large momentum acceptance storage ring. The project will be realized at the Karlsruhe Institute of Technology (KIT, Germany). Initially, the Ferninfrarot Linac- Und Test-Experiment (FLUTE), a source of ultra-short bunches, will serve as an injector for...
The proposed upgrade of ALBA to a 4th generation light source, ALBA-II, will involve several changes in the beam dynamics. The most significant change in the longitudinal plane is the addition of a harmonic RF system, which is expected increase the bunch length by at least a factor of three and raise the Touschek lifetime by a similar amount. However, RF systems with harmonic cavities can be...
The Hefei Advanced Light Facility (HALF) is a vacuum ultraviolet (VUV) and X-ray diffraction-limited storage ring light source. It has a relatively large dynamic aperture, and an injection scheme with a nonlinear kicker (NLK) was considered for the HALF. This kind of magnet was designed with a small gap shield in the central area to gain a flat magnetic field. A complete prototype has also...
Landau damping plays a crucial role in preserving single-bunch stability. In view of delivering the beam to the High-luminosity LHC (HL-LHC), the Super Proton Synchrotron (SPS) must double the intensity per bunch. In this intensity range, the loss of Landau damping (LLD) in the longitudinal plane can pose an important performance limitation. Observation of the beam response to a rigid-bunch...
Longitudinal microwave instabilities are driven by beam coupling impedance sources which have a very short wavelength compared to the bunch length. These instabilities can be a significant limitation to performance on an accelerator. In the CERN Proton Synchrotron (PS), microwave instability is mostly observed at transition crossing for ion and proton beams, when bunches are shortest. Vacuum...
The worldwide first in-vacuum elliptical undulator, IVUE32, is being
developed at Helmholtz-Zentrum Berlin. The 2.5 m long device with a
period length of 3.2 cm and a minimum gap of about 7 mm is to be
installed in the BESSY II storage ring. The device follows the Apple-II
design and features four magnet rows. Both the two bottom and two top
rows can be shifted longitudinally. This...
In the next-generation light sources, the bunch lengthening using the combination of the fundamental and harmonic cavities is a key technology to generate ultra-low emittance beam. Since the performance of the above bunch lengthening is limited by the transient beam loading (TBL) effect on the cavities, we proposed a TBL compensation technique using a wide-band longitudinal kicker cavity [1]....
The electron injection chain of the DELTA accelerator facility starts with a 90 keV electron gun, followed by a linear accelerator (70 MeV), a first transfer line (T1) between linac and booster, a booster synchrotron (70 MeV to 1.5 GeV) and a second the transfer line (T2) connecting the booster and the storage ring (1.5 GeV). Since DELTA does not use a fast topping-up injection mode, each...
Traditionally PIC solver compute electric field created by the beam as a mean field. The effect of particle collisions is normally neglected by the algorithm. In this proceeding we address how to include the collisions between the macro particles, and discuss the computational challenges and strategies to include the collisionallity in PIC solvers as particle-particle interaction. We present...
An injection-locked amplitude modulated magnetron is being developed as a reliable, effi-cient RF source that could replace klystrons used in particle accelerators that have superconducting cavities. This paper will describe the magnet system which is designed to provide a reasonably uniform field over the magnetron interaction region (IR). Most of the field in the IR is provided by a large...
In this report, we present our recent progress in the de-sign and high-power testing of the 2nd harmonic cavity for the China Spallation Neutron Source upgrade project. To achieve optimal performance, high-performance mag-netic alloy (MA) cores with dimensions of Ф850mm × Ф316mm × 25mm were meticulously developed and fabricated to serve as the load material for the radio-frequency (RF) cavity....
The transverse gradient undulator (TGU) concept is a way to enable short-gain length free electron lasers with laser-plasma accelerated electron bunches, although their energy spread is typically in the percent range. In this contribution, we report on the magnetic field measurements on a 40-period superconducting TGU designed, manufactured and commissioned at the Karlsruhe Institute of...
Magnetic Field Tools is an open source library being developed by the Insertion Devices and Magnets group at the ESRF. It is dedicated to the analysis of static magnetic field values obtained from simulations and measurements. Magnetic field models such as 2D and 3D multipoles in various geometries, as well as boundary element models, can be built from sets of field samples. The library was...
The Elettra 2.0 project involves the installation of more than 600 new magnets for the upgrade of the existing light source. All the magnets will be measured in house in a new magnetic measurement laboratory to be built and equipped by 2024. The measurements will be carried out over a period of two years and will consists of acceptance tests, magnetic characterization and, to meet the...
he Advanced Light Source (ALS) at the Lawrence Berkeley National Laboratory (LBL) is going through an upgrade (ALS-U) where the ALS triple-bend achromat will be replaced by a nine-bend achromat storage ring (SR) with an on-axis injection using beam swapping from a triple-bend achromat accumulator ring (AR). About 700 magnets will be used for the ALS-U accelerator systems. The paper gives an...
High-order corrector magnets will be required for the magnetic system of the HL-LHC inner triplets. These magnets are based on a superferric design thus the saturation of the iron poles affects the field generated in the aperture, i.e., the magnetic transfer function shows a nonlinearity. One of the challenges for the operations of these magnets is to find a suitable fit of the magnetic...
The new interest for a muon collider has motivated a renewed and thorough analysis of the accelerator technology required for this collider option at the energy frontier. Magnets, both normal- and super-conducting, are among the crucial technologies throughout the accelerator complex, from production, through acceleration and collision. In this paper we initiate a catalog of magnet...
The APS Upgrade storage ring will keep the same rf system that is currently used at APS. This rf system has amplitude and phase noise dominated by the lines at 60, 180, and 360 Hz. APS presently operates with a synchrotron frequency close to 2 kHz, which is far away from the rf noise frequencies, but APS-U will operate with a bunch-lengthening cavity, which could lower the synchrotron...
Work at the SNS beam test facility has focused on high dimensional and high dynamic range measurements of the medium energy (2.5 Mev) beam distribution. This is motivated by the need to understand and predict beam losses down to one-part-per-million. The initial demonstration of full-and-direct 6D phase space measurement was done at a current of 40 mA transported through the RFQ. Since that...
Landau damping represents the most efficient stabilization mechanism in hadron synchrotron accelerators to mitigate coherent beam instabilities. Recent studies allowed expanding the novel analytical criteria of loss of Landau damping (LLD) to the double harmonic RF system case above transition energy, providing an analytical estimate of the longitudinal stability. The threshold has a strong...
Nb3Sn superconducting radiofrequency (SRF) cavities have been an ongoing research topic for many years motivated by the potential for higher accelerating gradients and quality factors compared to niobium SRF cavities. The highest performing Nb3Sn cavities are manufactured using tin vapor-diffusion coating, which creates a Nb3Sn film with a surface roughness of around 100-200 nm. This is...
The planned Electron Ion Collider (EIC) has an Energy Recovery Linac (ERL) which provides Strong Hadron Cooling (SHC) in order to control the beam quality of the hadrons. This requires that the electron beam delivered to the cooling section be minimally perturbed by the preceding bunch stretcher necessary in the 100 GeV configuration. This paper evaluates different stretcher designs for the...
A system is being developed for the maintenance of a space-charge neutralising plasma from the residual gas within the LEBT of the Front End Test Stand (FETS) at UKRI-STFC Rutherford Appleton Laboratory. Space-charge neutralisation will occur when an ion beam is allowed to collide with and ionise a background gas with pressure greater than 10-4 Torr in the presence of a solenoid fringe field,...
The ESRF presently operates with the HMBA lattice that features beta-functions of 6.9 m and 2.7 m in the horizontal and vertical planes at the center of the the straight sections. These are not optimal for a length of in-vacuum undulator of approximately 2 m that is used at ESRF. New optics with reduced beta functions at the center of the straight section were designed to better match the...
In CLS, Deep Learning was applied to make a dynamic model for the Orbit Correction System (OCS). The OCS consists of 48 sets of BPMs BERGOZ (96 data sheets with 900 Hz recording) that measure the beam position and use the SVD matrix to calculate the strength of the orbit correctors (48 sets of Orbit Correctors 'OC'). The Neural Network was built, trained, and tested using 96 BPM signals. Five...
Sealab (SRF Electron Accelerator LABoratory) is composed of an SRF photo gun and an SRF booster, followed by a diagnostic line and a recirculation path for ERL applications. It is the follow-up project of bERLinPro, which ran from 2010-2020 at HZB. In an SRF injector, a single solenoid is sufficient to optimally focus the beam for small emittance. The alignment of the solenoid is crucial, as...
As a follow on to the 12 GeV upgrade to the Continuous Electron Beam Accelerator Facility, the front end of the DC photo-gun-based injector has gone through a phased upgrade. The first phase focused on the beamline between the gun and the RF chopper system, and the second phase addresses the beamline after the RF chopper system including replacing the capture section and quarter cryomodule...
Optical Stochastic Cooling (OSC), a beam cooling technique based on Stochastic Cooling, is in the early stages of experimental development. It uses radiation produced by the beam in an undulator magnet (the pickup) to correct the momentum deviation of particles downstream in another undulator (the kicker). The OSC mechanism was recently demonstrated at Fermilab’s IOTA ring using a passive...
Current-carrying wires have long been proposed as measures to mitigate beam-beam effects. Dedicated hardware has been installed at CERN Large Hadron Collider (LHC) and experimental sessions have been organised to study the beam dynamics in the presence of the wire compensators. In this paper, a diffusive model is presented to model the collected experimental data and its performance is...
Exploring the fundamental properties of materials, including niobium or Nb3Sn, in high-precision surface resistance measurements is relevant to superconducting radio-frequency (RF) technology. For the precise determination of the RF properties of such materials, the calorimetric measurement is carried out with a quadrupole resonator (QPR). Mathematically, a QPR model is governed by a set of...
An ongoing study at the Spallation Neutron Source (SNS) seeks to better understand and address potential multipacting issues associated with the Drift Tube Linac (DTL) RF vacuum windows. An analysis of several failed operational windows showed indications of excessive RF heating on the TiN-coated alumina ceramics. Coupled with vacuum bursts and arcing during conditioning and/or operational...
The Future Circular Collider (FCC) is a project of high performance particle collider. Several accelerating cavity technologies may equip it and are currently under study. One of them is the Slotted Waveguide ELLiptical (SWELL) superconducting (SC) cavity. It is a good candidate for nearly all the range of electron-positron interaction energies. It is made up of four independent quadrants...
SRF photoguns become a promising candidate to produce highly stable electrons for UEM/UED applications because of the ultrahigh shot-to-shot stability compared to room temperature RF photoguns. SRF technology was prohibitively expensive for industrial use until two recent advancements: Nb3Sn and conduction cooling. SRF gun can provide a CW operation capability while consuming only 2W of RF...
Nb3Sn on Nb thin films cavities by Tin Vapor Diffusion already show performance at 4.2 K comparable to Nb bulk cavities at 2 K, but a real breakthrough would be the use of copper (instead of Nb) as substrate, to enhance the thermal conductivity, opening up the possibility to cool down the cavity using cryocoolers instead of the more expensive helium bath.
Magnetron sputtering is the most...
In recent years, the use of machine learning methods has proved to be capable of considerably speeding up both fundamental and applied research. Accelerator physics applications have also profited from the power of these tools. This includes a wide spectrum of applications from beam measurements to machine performance optimisation.
PETRA III is one of the world's brightest...
Electromagnetic processes of charged particles interaction with oriented crystals provide a wide variety of innovative applications such as beam steering, crystal-based extraction/collimation of leptons and hadrons in an accelerator, a fixed-target experiment on magnetic and electric dipole moment measurement, a positron source for lepton and muon colliders, X-ray and gamma radiation source...
A new kicker power supply using SiC-MOSFETs is under development at J-PARC. SiC-MOSFETs enables the fabrication of compact high-speed pulse power supplies to replace thyratrons switch power supply. The base circuit uses an induction voltage superposition circuit of the LTD method, and the semiconductor module circuit consists of a radial symmetry type that achieves low noise. The three main...
Fixed Field Alternating Gradient Accelerators (FFAs) that follow the conventional scaling law have – by definition – high order multipole components in their magnetic fields. It is the presence of these nonlinearities that in many cases determines several important properties of the machine, including amplitude-dependent tune shift and dynamic aperture. Consequently, understanding of the...
We expanded the capability of the nonlinear optics from off-energy closed orbits technique proposed by Olsson et al. to include harmonic sextupole correction in storage rings. The existing technique was successfully used to correct the errors of chromatic sextupoles on the MAX-IV machine. However, it was not applicable to harmonic sextupoles, which are widely used in $3^{rd}$-generation light...
Crab cavities are fundamental components of the LHC upgrade in the framework of the HL-LHC project. These Radio Frequency cavities, operated at the appropriate frequency, ‘tilt’ the proton bunches to increase the luminosity at the collision points IP1 (ATLAS) and IP5 (CMS). During operation, the walls of the cavities are deformed due to the loading conditions. This deformation changes the...
In recent years the generation of high power millimeter wave and Terahertz radiation has progressed substantially, enabling electron beam manipulation and acceleration in structures with a footprint of several centimeters. However, in many experiments the external driving pulse is coupled collinearly into the waveguide structure which increases the coupling footprint relative to the wavelength...
An accelerating charged particle emits electromagnetic radiation. The motion of the particle is further damped via self-interaction with its own radiation. For relativistic particles, the subsequent motion is described via a correction to the Lorentz force, known as the Lorentz-Abraham-Dirac force.
The aim of this research is to use the Lorentz-Abraham-Dirac force to computationally...
A new set of nonlinear beam manipulations have been recently proposed, with the goal of extending the transverse beam splitting that is routinely used at the CERN PS to deliver beam to the SPS for fixed-target physics. Using a simple Hamiltonian model, it has been shown how the transverse emittances can be shared by crossing a two-dimensional nonlinear resonance. Moreover, it has been shown...
SIRIUS is the 4th generation storage ring-based synchrotron light source built and operated by the Brazilian Synchrotron Light Laboratory (LNLS). Beam accumulation at SIRIUS storage ring occurs in an off-axis scheme, using a nonlinear kicker (NLK), for which the efficiency depends on a sufficiently large dynamic aperture (DA). This work reports on the application of online optimization using...
OPAL (Object Oriented Parallel Accelerator Library) is a C++ based massively parallel open-source program for tracking charged particles
in large scale accelerator structures and beam lines, including 3D space charge, collisions, particle-matter-gas interaction, and 3D undulator radiation.
The meticulous parallel architecture allows large and difficult problems, including one-to-one...
The CEBAF energy upgrade will require magnets with high fields to bend electron beams of up to 22GeV in the 80.6m radius tunnel. A peak field in excess of 1.5T, together with a large gradient of 40T/m or more, are used in its fixed-field arc lattice to bend multiple recirculation energies in a single pipe. Additionally, the magnet must have an open midplane to allow synchrotron radiation to...
Cryogenic permanent-magnet undulators (CPMUs) have emerged as a focal point in the development of short-period undulators. At the Taiwan Photon Source (TPS), two 2-meter CPMUs have been developed using different magnet materials and cooling techniques. Spe-cifically, a PrFeB-based CPMU, equipped with cryocooler cooling, and a NdFeB-based CPMU, utilizing liquid nitrogen (LN2) tank cooling, have...
The energy of a collider is proportional to the field of the dipoles and to the length of the arcs available to dipoles. A way to increase energy without increasing the field or making a longer tunnel is to have a larger filling factor (fraction of the arcs covered by dipoles), ie to reduce the space dedicated to quadrupoles, correctors, interconnections ... In this paper we discuss three...
The new generation of storage rings aims to push the limits of the luminosity and the size of the electrons beam that can be achieved. One of such planned machines is the e+/e- Future Circular Collider (FCC-ee) with 100km circumference. The FCC-ee lattice components can be subject to random misalignments and field errors. These errors can adversely affect the beam's closed orbit and beam...
In shanghai, a hard X-ray free electron laser facility named SHINE is under construction which is composed of three undulator lines. As part of the facility, it is preferable to incorporate a beam distribution system just before the undulators to provide suitably tailored beams for diverse experiments. In order to drive a FEL, a good overlap between the electron beam...
Electropolishing (EP) and buffered chemical polishing (BCP) are conventional surface preparation techniques for superconducting radiofrequency (SRF) cavities that remove damaged material from the cavity surface. One main issue with EP and BCP treated SRF cavities is high field Q-slope (HFQS), a drop in quality factor at high gradients that limits quench field. High gradient performance in EP...
In view of the High-Luminosity (HL-LHC) upgrade of the LHC collimation system, different materials were investigated to determine how the jaws of the new collimators could be manufactured to meet the demanding requirements of HL-LHC, such as thermomechanical robustness and stability, RF impedance, UHV, etc. During the Long-Shutdown 2 (LS2), five primary and 10 secondary low-impedance...
During Long Shutdown 2 (2019-20), the injector chain of the Large Hadron Collider (LHC) has been upgraded to reach the High Luminosity LHC goals in terms of beam intensity and brightness. In the CERN Proton Synchrotron (PS), this upgrade consisted in hardware modifications to double the intensity at extraction, while preserving the transverse emittance available from the CERN PS Booster. The...
At TTX, we try to use machine learning to give the virtual detection of the beam spot. The prediction of beam spot is difficult when the dimension becomes larger. We try to use PCA to make it smaller and use Neural networks to predict it. However, the weight of different dimension varies widely. We predict them parallel and get good results with easy neural networks.
Permanent Magnets (PM) and Electro Magnets (EM) with conventional resistive conductors are widely used in particle accelerator. The different applications include all types of multipoles, bending magnets, chicanes, kicker and undulators.
Both types of Magnets have specific advantages and disadvantages, state of the art PM comprise expensive raw materials like Nd, Dy, Tb and Co and reach only...
Transverse resonance island buckets (TRIBs) have been successfully observed at the Cornell Electron Storage Ring (CESR) after optimizing the distribution of seventy-six sextupoles to achieve the desired amplitude-dependent tune shift and the resonant driving term near a third-order resonant line (3vx=2). A novel knob is created to adjust the resonant driving term h22000 while minimizing the...
We present a physics-constrained neural network (PCNN) approach to calculating the electromagnetic fields of intense relativistic charged particle beams via 3D convolutional neural networks. Unlike the popular physics-informed neural networks (PINNs) approach, in which soft physics constraints are added as part of the network training cost function, our PCNNs respect hard physics constraints,...
We present the latest updates to the PLACET3 tracking package which focus on the impact of both transverse and longitudinal wakefields on a beam travelling through accelerating and decelerating structures. The main focus of this update was the first implementation of 6D tracking through Power Extraction and Transfer Structures (PETS) for the Compact Linear Collider (CLIC) which is described...
Plasma processing can be used to mitigate hydrocarbon-related field emission in SRF cavities in situ in cryomodules. At Fermilab we developed plasma cleaning for LCLS-II 1.3GHz N-doped cavities and we successfully applied to the LCLS-II High Energy verification cryomodule (vCM). This test demonstrated that plasma processing can be a valuable tool to mitigate both field emission and...
As a part of the effort to expand the capabilities of CE-BAF 12 GeV (Continuous Electron Beam Accelerator Facility) at Jefferson Lab, the addition of a polarized positron source is considered. This capability would provide acceleration of high duty-cycle polarized posi-trons, with spin >60% polarization, through the same main CEBAF accelerator machine with appropriate mag-net field reversals...
A beam collimation in the distribution system is designed to protect the undulator and beam pipe in the SHINE FEL.A tracking with a big initial distribution provide a result of the collimation efficiency. Detailed simulation studies about the evaluation of the available collimation design limits for the acceptance of the undulator is described.
The compensation of the long-range beam-beam interactions by DC wires is currently being investigated as an option for enhancing machine performance in the framework of the High-Luminosity LHC Project. In this paper, we report and comment on the potential of wire compensation during the first HL-LHC run. The results are based on numerical simulations and optimisations of the machine dynamic...
A permanent dipole magnet assembled by Sm2Co17 was fabricated and measured at NSRRC. The main magnets were consisted of several small magnet blocks. A simple coil was wound to measure the total flux of permanent magnet. The flux coil was compared and calibrated by the Helmholtz coil using small magnet block. A flux sorting process was implement to obtain more homogeneity magnetic field. A NiFe...
Superconducting magnet technology is one of the foundations of large particle accelerator facilities. A challenge with operating these systems is the possibility for the magnets to quench. The ability to predict quenches and take precautionary action in advance would reduce the likelihood of a catastrophic failure and increase the lifetime operability of particle accelerators. We are...
Research Instruments (RI) and Thales have been producing the first two prototype 1.5 GHz fundamental power couplers for the VSR (Variable pulse length Storage Ring) DEMO since early 2021 and delivered these prototypes in late March 2023. These couplers are designed to provide up to 16 kW power to two 1.5 GHz superconducting cavities of the VSR DEMO module and provide variable coupling with a...
In order to ensure strict phase synchronization between power supplies, CSNSRCS resonant power supply receives 25Hz and 100KHz timing signals provided by the timing system. The 25Hz rising edge is used as the trigger signal of RCS cycle, and the 100KHz signal is the AD sampling clock of the power digital controller. These two signals are distributed by the timing system according to the clock...
The Insertion device development and measurement laboratory of Devi Ahilya University, Indore, India has ongoing activities on undulator design, development and measurements. A new type of undulator known as Asymmetric magnet pole with upper and lower structure having different period lengths will be designed and fabricated. Asymmetric magnet pole undulator has a special demanding field...
The EIC to be built at BNL is a unique high-energy, high-luminosity, polarized electron-proton/ion collider. The EIC accelerator complex consists about 10 new RF and SRF systems operating with frequencies spanning 24 MHz to 1,773 MHz, requiring at least 60 new high power fundamental power couplers (FPCs). These couplers will operate in either pulsed mode or CW modes with peak traveling wave...
Recent efforts at SLAC aim at developing high-power accelerators powered by compact, high-efficiency rf sources such as klystrons and Inductive output tubes (IOT). In particular, a high-efficiency IOT is an electron-beam-driven RF source employed in the UHF band that offers high efficiency at variable output power levels. Due to the improved linearity, high efficiency, and reduced size, it is...
FCC-ee is a proposed lepton collider with a circumference close to 100 km to produce an unprecedented amount of luminosity. The FCC-ee optics tuning working group is addressing one of the most critical aspects of the FCC-ee, that is the recovery of the optics design performance in presence of realistic imperfections.
Various teams from laboratories all around the world have got together to...
The ALBA-II upgrade lattice to a diffraction limited soft X-rays storage ring calls for an emittance smaller than 200 pm*rad in a 269 m circumference at an energy of 3 GeV. In this paper we report on progress of the 6BA lattice with distributed chromatic correction. This lattice relies on transverse gradient dipoles and reverse bends to suppress the emittance. Several modifications to the...
The SOLEIL II storage ring project will require an injected beam with small transverse and longitudinal sizes. To meet this requirement, a new multi-bend 14BA Higher-Order Achromat lattice has been de-signed to reduce the booster emittance from the pre-sent 140 nm.rad to 5 nm.rad @ 2.75 GeV. In this paper we report the progress in the booster beam dynamics studies, considering the linac energy...
Tracy, the code base used for designing synchrotron light sources with predictable performance, has been significantly refactored. Furthermore it now uses mad-ng gtpsa library.
We describe the achieved progress, discuss its python interface. We show how to use it for achieving a robust design for a modern synchrhotron light source.
The CERN ISOLDE facility is currently equipped with two uncooled iron blocks acting as beam dumps. In order to guarantee the reliability and safety of the installation for the years to come, a study has been launched to evaluate the possibility to exchange the ISOLDE beam dumps during LS3. The consolidation would also allow compatibility with the 2 GeV and intensity upgrade being discussed....
PyTao is a Python interface to the Bmad based Tao program for accelerator design and simulation. This enables advanced design and optimization beyond the normal capabilities of Tao as well as simplifying the use of Tao as an online model for an operating accelerator. Here we will describe this interface and some of its applications, including online models for the the LCLS and LCLS-II at SLAC...
Vacuum chambers of flat aspect ratio are source of a quadrupolar component of long-range resistive wall wake fields whose amplitude only depends on the trailing test particle.
In multi-bunch filling this leads to an accumulation of the long-range quadrupolar resistive wall wake field which expresses in multi-bunch tune shifts on both planes. The tune shifts were measured at the ALBA storage...
ER@CEBAF is an effort to demonstrate multi-GeV multi-pass energy recovery with a low beam current in CEBAF. The race-track-shaped CEBAF geometry allows its linacs to accommodate multiple energy beams simultaneously. However, five energy recovery passes complicate the beamline optics design process. Individual recirculating arcs each transport one beam energy, and are shared between...
This report discusses the design of a current feedback component for a TPS correction magnet power supply. The component utilizes a low-cost and small-sized TI INA253 resistor combined with a temperature compensation control circuit to improve the output current thermal equilibrium time. With these measures, the system achieves thermal equilibrium quickly, resulting in improved performance....
Superconducting materials such as niobium have been extremely useful for rf accelerator technology but require low temperatures for operation ~2-4 K. The development of high temperature superconductors (HTS) is promising due to their transition temperature in excess of 80 K. In this work we are exploring the high-power RF performance of such materials at X-band (11.424 GHz). We are testing two...
Controlling beam losses is of paramount importance in superconducting particle accelerators, mainly for ensuring optimal machine performance and an efficient operation. Models based on global diffusion processes, in which the form of the diffusion coefficient is the stability-time estimate of the Nekhoroshev theorem, have been studied and proposed to investigate the beam-halo dynamics. Recent...
As a scientific system with many subsystems, particle accelerator system is getting more complex， due to rising demands on accelerator performance. Meanwhile, it is increasingly difficult to study such complex systems using traditional research methods based on physical models. At present, machine learning (ML) is mature enough to be applied in accelerator science such as beam diagnostics and...
A algorithm is demonstrated which performs first-principles tracking of relativsitic charged-particles for determining the power they deposit into their surroundings (in particular, blackbody cavities and pillbox accelerating cavities). A computationally costly, but highly accurate covariant approach is used, which employs retarded vector potentials for trajectory integration instead of...
In CSNS, there are more than 350 devices in the accelerator power supply system, which respectively provide precise excitation current for the magnet load. Therefore, the stable operation of the power supply is an important prerequisite to ensure the beam quality, and also one of the necessary conditions for the normal operation of the CSNS.
In accelerator power system, digital controller is...
The compact 166 MHz HOM-damped quarter-wave superconducting cavities for HEPS have complex geometries, resulting in streak defects on the inner surface of the cavity after BCP etching. Surface areas with low flow velocity from fluid dynamics simulations coincide with defects observed on the cavity inner surface. Based on the 166 MHz cavity structure, an improved BCP setup with holes and discs...
As the precise sensor system for monitoring the rela-tive altitude changes among multiple points, the capacity hydrostatic leveling system (HLS) is widely used in particle accelerators. To expand its application in provid-ing the elevation constraint for the control network ad-justment, the research on the issue of the HLS for alti-tude difference measurement between multiple points is carried...
One of the interesting topics among accelerator physicists in the last decades has been the resistive wall impedance of vacuum chambers with general cross sections. The resistive wall impedance of a round pipe was calculated more than half a century ago, followed by parallel plates, rectangular pipes, and, in more recent years, oval shapes. Analytical solutions usually require some...
The ultra-low emittance specification of the SOLEIL II storage ring requires a challenging lattice design of the booster that will inject the beam into it. The dimension of the vacuum chamber in the new booster must be reduced compared to that in the present machine. The resistive-wall (RW) instability is then expected to become more important than in the current booster. However, the...
The cryomodule qualification test stand (TS2) at Lund has been commissioned fully in 2021 and is delivering the components for the installation in the linac, which started in Q1 2023 after the end of the cryogenic distribution system commissioning.
All the available medium beta cryomodules have been tested and the facility is now delivering the high beta cryomodules for the full scope of the...
The accelerators constituting the LHC injectors chain have been gradually built and commissioned since the CERN foundation in the fifties. The operation of the Proton Synchrotron, the Proton Synchrotron Booster and the Super Proton Synchrotron started in 1959, 1972 and 1976 respectively. During the Long Shutdown 2 (LS2) of the CERN accelerator complex in 2019 and 2020, a large upgrade of these...
Recent efforts have shown that the SRF technology developed for accelerators can be successfully applied to new applications, including quantum computing, dark matter searches and beyond the standard model physics. The ultra-high quality factor of SRF cavities can allow to achieve unprecedented sensitivity in fields outside of the usual accelerator applications, for examples in dark photon and...
Future high duty cycle (HDC) operating modes are under development for the
European XFEL. A L-band superconducting RF (SRF) gun is foreseen as the
injector operating continuous wave (CW). To preserve the small beam
emittance distracting effects like RF kicks from the power coupler,
trapped higher order modes (HOMs) in the cavity end group and RF field
asymmetries need to be considered and...
We present here the RF test program of the ESS TS2. Several tools have been prepared at TS2 for the later stages of the technical commissioning in the linac. Automated tools for tuning the cavities to resonance using spectral analysis or cavity gradient calibration have been deployed and tested to assist the later stages of facility commissioning.
In this paper, the design of a compact C-band SLED RF Pulse Compressor for a Very High Electron Energy (VHEE) FLASH machine is presented. A spherical cavity RF pulse compressor - selected because of its compactness and relative ease of fabrication - is adopted to compress the 50 MW 3 µs RF pulse, down to 1 µs obtaining a peak power gain greater than 3. The main parameters – operating resonant...
A pulse compression system based on double-height waveguides was designed for the Klystron-based CLIC main linac. The optimized power gain of the system is 3.81 with the particular pulse shape required for the CLIC-K accelerating structure. This pulse compression system consists of a main Barrel Open Cavity (BOC)-type pulse compressor and 4 novel correction cavities. The BOC pulse compressor...
A new RF Module was designed for the Klystron-based CLIC main linac. The new module deploys two X-band klystrons to feed eight CLIC-K accelerating structures giving a beam energy increase of 156 MeV. This module will use a double-height waveguide distribution network which can reduce the RF power loss in the network by about 37%. All the RF components were redesigned to match the double-height...
The brightness can be increased by minimizing the emittance in the light source, but the reduced emittance also increases the number of collisions of electrons in the beam bunch. Therefore, the bunch lengthening by using the 3rd harmonic cavity reduces the collisions of electrons and increases the Touschek lifetime. Since the resonant frequency of the main RF cavity is 500 MHz, the resonant...
QWR cavities are prepared for beam commissioning. RF conditioning is performed for each QWR cavity. The total heat load including static and dynamic heat loads are measured for each cavity. The helium pressure fluctuation is reduced by changing the flow rate, supply pressure, return pressure, liquid helium level in reservoir, cryogenic valve control, etc. The cavity pressure is monitored...
What happens when the temperature reaches absolute zero? Physical phenomena at the zero-temperature limit are studied in accelerator physics. The background temperature of the universe goes down as long as expansion goes on. The BCS resistance of a superconducting cavity is shown as a function of temperature at different frequencies. The surface resistance of the Nb superconducting cavity is...
Tuning becomes essential at the end of manufacturing an RFQ to acquire the operating frequency and achieve the required RF field profile along the length of the structure. During commissioning, unexpected detuning events may also necessitate tuning to obtain the original design field profile. Proper separation of quadrupole and dipole modes is needed to maintain the desired field distribution...
Abstract
A geometric control theory method is outlined & pre- sented to improve the on & off-momentum dynamic aper- ture for synchrotrons. And applied to the two lattice op- tions/solutions for BESSY III. A guideline is also provided for how to estimate the resulting performance for the “real lattice. The so-called tune confinement approach [32].
In this paper, we present a study of the transformation of a magnetized electron beam from round to flat and back to round using a skew quadrupole triplet. Electron cooling of hadron beams requires a magnetized electron beam, which can be generated from an RF photoinjector. However, such a beam is coupled in four-dimensional phase space, making it difficult to transport through beamlines. To...
RUEDI, the Relativistic Ultrafast Electron Diffraction and Imaging facility for the UK, is a planned facility that will deliver single-shot, time resolved, MeV electrons for imaging and ultrafast (~10 fs) diffraction. The facility naturally separates into two lines, both fed by the same RF gun. The first line is for microscopy and imaging whereas the second is dedicated to diffraction....
With the development of Mega-electron-Volt ultrafast electron diffraction technology, electron microscopy based on photocathode radio-frequency (RF) electron guns has become a promising tool for high spatiotemporal resolution and shows obvious advantages of suppressing the space charge effect. An ultrafast electron microscopy is being developed at HUST. Russian quadruplet (RQ) based electron...
A beam transport section using the scaling fixed-field alternating gradient-type (FFAG) magnets is designed to transport laser plasma accelerator (LPA) electron beams to a specific application. This beam transport section has a large momentum acceptance, which is able to collect and transport the LPA beams with a momentum acceptance of up to 10%. Also, using the periodical FFAG magnet cells,...
In the injector section of electron linacs, both internal space charge forces and wakefield effects influence the beam dynamics. To account for both effects, full electromagnetic PIC simulations are usually required. Unfortunately, PIC solvers require large computational resources. On the other hand, particle-tracking codes in the bunch reference frame describe the beam dynamics under...
This work investigates the behavior of a free-electron laser (FEL) system composed of a slowly modulated wiggler field, constant laser field amplitude, and self-consistent fields due to the charged particles. The dynamics of each particle of the beam is studied through a Hamiltonian formalism, from which a ponderomotive approach represents its mean motion. The purpose of the present analysis...
The electron ion collider, the next generation nuclear physics collider is being actively studied. In order to achieve the designed luminosity 10^34/cm^2/s with a reasonable lifetime, an efficient coherent electron cooling scheme was proposed to reduce the hadron beam emittance and counter intrabeam scattering. Such a cooling scheme requires a good electron beam quality with a small energy...
Modern SRF applications require precise control of a wide range of material properties, from microscopic material parameters to macroscopic surface structures. Historically, Nb has been the primary superconducting material in SRF cavities. The past decade has seen increasing amounts of research into the development of cavities using next generation materials, such as Nb3Sn. These materials...
The Figure-8 storage ring (F8SR) concept for fusion reaction research in context of astrophysics is under development at Frankfurt University. In contrast to traditional storage rings, a guiding longitudinal magnetic field is used for confinement of very low energy charged particle beams continuously with high transverse momentum acceptance. Due to the strong magnetic field level (B=6 T), low...
In the KIT storage ring KARA (Karlsruhe Research Accelerator), two parallel plates with periodic rectangular corrugations are planned to be installed. These plates will be used for impedance manipulation to study and eventually control the electron beam dynamics and the emitted coherent synchrotron radiation (CSR). In this contribution, we present simulation results showing the influence of...
The effect of radiation reaction is often negligible in inverse Compton scattering. However, in the nonlinear Compton regime, at high laser fields and high electron beam energies where electron recoil must be properly accounted for, there is experimental data which demonstrates the onset of radiation reaction * . We model the radiation reaction as a series of emissions from individual...
Third-order resonance lines will have a detrimental effect on the high-intensity operation of the Recycler Ring (RR), under the current Proton Improvement Plan (PIP-II) for the Fermilab Accelerator Complex. Increasing intensity will increase space charge effects, leading to the excitation of normal and skew sextupole lines. Dedicated normal and skew sextupoles have been installed in order to...
The Function Generator/Controller is CERN’s flagship controls platform for electrical power converters. Despite a proven track record, the current generation (FGC3) begins to show its age through performance limitations and component obsolescence. The requirements for its successor are ambitious: 100 kHz regulation rate (a 10-fold increase); reuse of a CERN-developed hardware platform...
The half-integer resonance is considered to be one of the strongest effects limiting the intensity of the FAIR SIS100 heavy-ion synchrotron which is currently under construction at GSI. Results of simulations under realistic synchrotron-operation conditions show that for bunched beams, a relatively small gradient error can result in a large half-integer stop-band width significantly reducing...
Many current accelerators use cavities that are manufactured as two half cells that are electron beam welded together, across the peak surface current of the cavity. This weld can limit the performance of Thin Film (TF) coated cavities by causing an increase in the surface resistance. Many problems with the coating process for TF Superconducting Radio Frequency (SRF) cavities are also due to...
Bunch lengthening with a double radio-frequency (rf) system combining fundamental and harmonic cavities (HCs) is essential in achieving extremely low emittance along with suitable lifetime as required for ring-based fourth-generation synchrotron light sources in the low-to-medium energy range.
Recent studies have pointed out that, in many cases, an unstable beam motion, as so-called...
The question we try to answer in this paper is: what is the standard error of using particle tracking result to represent the real beam parameters? Or how much confidence do we have when we say that the tracking gives the correct theoretical prediction? Particle tracking or numerical simulation in general is used by accelerator physicists every day and we believe this question needs a definite answer.
This report presents new investigations on beam dynamics for the separation beamline which allows to transport and compress electron bunches from the second electron source MIST to the first acceleration section of MESA. Several beamline configurations are compared concerning the capability for transport of elevated bunch charges.
The Accelerator Toolbox (AT) is a multipurpose tracking and lattice design code relying on a C tracking engine. Its MATLAB interface is widely used in the light source community for beam dynamics simulation and can be integrated in control systems through the MATLAB Middle Layer. In recent years major effort was made to develop a python interface to AT: pyAT. In this framework, several...
The RF system for storage ring in TPS is adopted two sets of 500 MHz KEKB-type SRF modules, with total operating voltage of 3.2 MV. Its power is provided by two sets of klystron-type transmitters with an output power of up to 300 kW, and the RF feedback loop is controlled by analog LLRF system. Since the RF system started to operate, it has been continuously improved and introduced new...
MAD-X is a popular beam optics code used to design, model and operate a large number of synchrotons and linacs. In this paper, we present the features added in the most recent versions and improvements we intend to make in future releases. Physics models have been added and improved to support the needs of the Future Circular Collider (FCC) and the Electron Ion Collider (EIC), regarding...
A 4th generation storage ring based light source is being developed in Korea since 2021. It features < 100 pm rad emittance, about 800 m circumference, 4 GeV e-beam energy, full energy booster injection, and more than 40 beamlines which includes more than 24 insertion device (ID) beamlines. This machine requires about ~1300 magnets including dipole, longitudinal gradient dipole, transverse...
Wuhan Advanced Light Source (WALS) is a proposed 4th generation light source, which accelerators include a 1.5 GeV Linac, 1.5 GeV storage ring and one beam transport line. The ring lattice consists of 8 identical units of 7BA. In each unit, there are 7 longitudinal gradient dipoles with transversal gradients, 10 quadrupoles, 6 sextupoles, 4 anti-bending gradient dipoles. Moreover, a combined...
The MQXFB magnets are superconducting quadrupoles with nominal peak field on the conductor of 11.3 T. With their magnetic length of 7.2 m, they stand as the longest Nb3Sn accelerator magnets designed and manufactured up to now. Together with the companion MQXFA 4.2 m long units, built by the US Accelerator Research Program, they are at the heart of HL-LHC, as they shall replace the inner...
Super Fragment Separator (Super-FRS) is the highest priority accelerator facility in construction of the FAIR at GSI, Darmstadt Germany. Super-FRS will provide desired exotic isotope beams to various experiment sites for fundamental researches. The high energy branch of Super-FRS will be the earliest to be built and will enable to execute the first experiment of FAIR.
Key elements of the...
The proposed PETRA IV electron storage ring, that will replace DESY’s flagship synchrotron light source PETRA III, will feature a horizontal emittance as low as 20 pm∙rad. It is based on a hybrid six-bend achromat lattice. In addition to the storage ring PETRA IV, DESY IV booster synchrotron and the corresponding transfer lines will be renewed. About 4000 magnets will be manufac-tured. Some of...
SOLEIL, the French third-generation synchrotron radiation facility, is in the TDR phase of its upgrade to a new fourth-generation synchrotron light source, called SOLEIL II. Its storage ring lattice design has evolved over the last year to better adjust its parameters taking into account the results of the mechanical integration, more realistic magnet design~[1], and the geometrical...
Superconducting dipoles with a strong curvature (radius smaller than 2 meters, for an aperture of about 100 mm and a length of 1-3 meters) are required for applications where compactness is key, such as the synchrotron and gantry for Carbon-ion therapy developed within the European program HITRIplus.
Such magnets challenge several assumptions in the field description and put to the test the...
The High Energy Photon Source (HEPS), which is a 6 GeV diffraction-limited storage ring (DLSR)-based synchrotron light source, is under construction in Beijing, China. HEPS consists of a Linac, a booster synchrotron, and a storage ring. The HEPS booster is proposed to operate in multi-bunch mode. And the 5-cell PETRA-type cavity, which is rich in high-order modes (HOMs), is chosen to be used...
The ongoing FCC-ee collider design aims at optimizing beam parameters and developing the different accelerators systems. For this reason, the coupling impedance modeling is in evolution following the design of the collider vacuum chamber and hardware components. Respectively, studies of collective effects and instabilities are continuously updated and refined. In this paper we describe the...
Beam-beam interaction in FCC-ee can be seriously affected by the vacuum chamber coupling impedance resulting in a safe tune areas reduction, tune shifts and spread, bunch length and energy spread variation. The interplay of the two effects have a drastic impact on the stability of colliding bunches and respectively on the achievable luminosity. In this paper beam-beam collisions in FCC-ee with...
Longitudinal beam manipulation have been widely employed for various scientific and industrial applications in many hadron (heavy ion or proton) synchrotrons. One of the most important manipulations is the longitudinal bunch merging based on the dual rf system. For high-intensity hadron beams, longitudinal space-charge matching and cavity beam loading matching and compensation are of practical...
Modelling electron cloud driven instabilities using a Vlasov approach enables studying the beam stability on time scales not accessible to conventional Particle In Cell simulation methods. A linear description of electron cloud forces, including the betatron tune modulation along the bunch, is used in the Vlasov approach. This method is benchmarked against macroparticle simulations based on...
Intra-beam scattering (IBS) is one of the prominent effects for low-emittance rings resulting in a significant growth of the emittance, energy spread, and bunch length. This effect is partially mitigated by the bunch lengthening caused by the longitudinal impedance. However, a significant bunch lengthening provided by higher-harmonic cavities is needed to keep the emittance low enough for...
We present a study of the systematic uncertainties in beam size determination using sextupole strength variations. Variations in strength of a sextupole magnet in a storage ring result in changes to the closed orbit, phase functions and tunes which depend on the position of the beam relative to the center of the sextupole and on the beam size. We take advantage of the beam-based measurements...
Xi'an 200MeV proton application Facility, as known as XiPAF, is upgraded to a heavy ion synchrotron, which replace H^- stripping injection with multiturn injection scheme. New synchrotron circumference is much bigger than original one for injection equipment installation space, which means that this heavy-ion lattice is much different from original proton lattice. Simulation is performed with...
Al2O3 is one of the potential insulator materials in the superconductor-insulator-superconductor (SIS) multilayer coatings of superconducting radio-frequency (SRF) cavities for pushing their performance limits.
We report on the successful coating of two 1.3 GHz Tesla- shaped SRF cavities with 18 nm and 36 nm layers of Al2O3 deposited by thermal atomic layer deposition (ALD). The coating...
The Elettra 2.0 upgrade project is a new storage ring that will replace the existing Elettra. Among the project's flagships are those of three beamlines with a photon flux generated by dedicated bending magnets of up to 10^13 ph/ses at 50 keV. Since a magnetic field of around 6 tesla is needed to do this, the magnet designed for those beam lines will employ superconducting technologies, for...
At the Facility for Antiproton and Ion Research in Darmstadt, Germany, fast-cycled superferric magnets will be utilised for ion optics in the main accelerator SIS100. After an intense testing campaign, the full series of dipole magnets has been equipped with cryogenic beam vacuum chambers and is ready for tunnel installation. Currently ongoing is the procurement of the quadrupole and...
The microbunching instability (MBI) driven by beam collective effects can cause significant electron beam quality degradation in advanced x-ray free electron lasers. Typically, multiple stage magnetic bunch compressors used to generate high peak current electron beam will dramatically amplify the microbunching instability. In this paper, by redesigning the solenoid elaborately and adopting a...
Annealing of niobium (Nb) cavities in UHV is crucial for the performance in the later cryogenic tests and operation. Recently, a so-called “mid-T bake” treatment has exhibited very high-quality factors for Nb cavities. In this way, the first set of mid-T treated samples were produced with cavities at Zanon Research & Innovation Srl. The cavity performances have been improved with lower BCS and...
The performance of superconducting cavities depends extremely on the material and surface properties. In the last decades processes have been developed for the successful series production of accelerating cavities needed for large scale facilities like the European XFEL. A main feature of these cavities are relatively large beam ports on both sides which can be used for the surface treatment...
The self-consistent nonlinear dynamics of a relativistic charged particle beam interacting with its complete self-fields is a fundamental problem underpinning many of the accelerator design issues in high brightness beam applications, as well as the development of advanced accelerators. A novel self-consistent code is developed based on a Lagrangian method for the calculation of the particles’...
Elliptically polarized undulator (EPU) plays an essential role in providing circularly polarized light from the third generation to upcoming synchrotron light sources. To meet the demand of energy tuning, the operation is also discussed to change from the adjusted gap method to the adjusted phase method in many of the designs. However, the adjusted phase operation causes a transverse field...
Radio-frequency (RF) modulations can influence the microbunching instability dynamics and serve to eventually control them with reinforcement learning (RL) methods. Implementing such a feedback system at the Karlsruhe Research Accelerator (KARA) will require that the action decided by the RL agent, in this case an RF modulation, is applied effectively to the electron beam. Such a modulation...
A new high intensity fixed target facility could be accommodated at CERN by fully exploiting the Super Proton Synchrotron. Multiple physics experiment proposals such as BDF/SHiP, NA62-BD, HIKE and SHADOWS are being considered. Amongst the different possibilities to locate such experiments and their respective target complex at CERN, the ECN3 hall in the North Area has been selected for further...
A major part of the 520 MeV Cyclotron's RF system is the high-power RF amplifier. The amplifier is based on eight 4CW250,000B tetrodes. A new high-power tetrode or a high-power tetrode that underwent refurbishing could trip the RF system through inner sparks. The likelihood of those sparks should be reduced prior to applying nominal power to the new and refurbished tetrodes. This could be...
Electromagnets have traditionally been used in accelerators due to their wide range of tuneability with high accuracy, but are a major factor in power consumption due to resistive losses in the coils and inefficiencies in power and cooling systems. Use of permanent magnets can greatly reduce power consumption, but it has proved difficult to produce the same range of tuning with comparable...
In this paper, the nonlinear coupling resonance $2 Q_x -2 Q_y = 0$ is studied by means of a Hamiltonian model. The detailed analysis of its phase-space topology unveils the possible phenomena that can occur when crossing adiabatically such a resonance. These considerations are probed by means of numerical simulations carried out using a symplectic map and the results are presented and...
Classical canonical Lagrange for the electromagnetic potentials has been formulated for beam-wave interaction enclosed by periodic structure or slow wave structure (SWS). The analysis procedure is based on expanding the potentials in the Lagrange of the given SWS in terms of the solenoidal and irrotational eigenmodes of a canonical cavity with cross-section enclosing that of the original...
In preparation for the High Luminosity phase of the LHC at CERN, to start in 2029, a refurbishment of the electronics of the CMS electromagnetic calorimeter (ECAL) is planned. The ECAL barrel section is organized in 36 elements called Supermodules (SMs), 18 in each side. All SMs, weighing about 3 tons each, must be ex-tracted, upgraded and inserted again during the Long Shutdown 3 (LS3) using...
The superconducting radio-frequency (SRF) community has shown that introducing certain impurities into high-purity niobium can improve quality factors and accelerating gradients. We question why some impurities improve RF performance while others hinder it. The purpose of this study is to characterize the impurity profile of niobium with a low residual resistance ratio (RRR) and correlate...
The National Synchrotron Radiation Research Cen-ter (NSRRC) has developed a 320 kW solid-state am-plifier based on an 80 kW solid-state amplifier. In the design of the 80 kW amplifier, the DC power supply and solid-state amplifier racks were separated, with the DC power supply providing power to the solid-state amplifier power terminals through cables. This separa-tion allows the DC power...
The effect of both existing and the planned insertion devices on linear optics, dynamic and momentum aperture was modeled using the kick map approach. Cross check for some IDs have been done with different tracking codes. Mitigation strategy for avoiding the crossing of a 4th order resonance line, excited by some of the IDs, is proposed.
The High Luminosity Large Hadron Collider (HL-LHC) project is an upgrade of the LHC aiming to increase by a factor 10 the harvested integrated luminosity foreseen early 40s. During Long Shutdown 3, scheduled to begin at the end of 2025, nearly 1.2 km of accelerator components, including a range of services spread across surface and underground facilities, will be replaced with new equipment...
The Rapid Cycling Synchrotron (RCS) of the Electron Ion Collider (EIC) is the injector of the Electron Storage Ring (ESR). The dynamic range of the RCS is from 0.4 GeV to 18 GeV. The RCS will use normal conducting dipoles, quadrupoles, and sextupoles. With errors to the main dipole field and misalignment to the elements included in the model, an orbit correction scheme has been developed....
The resistive contribution of the vacuum chamber is a significant part of the impedance budget. Due to the NEG-coated re-designed ILSF vacuum chamber, the resistive-wall effects must be carefully studied. The resistive impedance of the insertion devices and general cross-section of the storage ring was calculated by CST and WI2D code. In addition, the fast-correctors containing a resistive...
Recent studies have shown that accelerating $+19^{\circ}$ off-crest in all RF cavities in the MAX-IV linac reduces voltage-induced timing jitter from the klystrons. The current bunch compressors in the linac have fixed first-order longitudinal dispersion, and the RF phase is varied to control the amount of compression. Variable bunch compressor designs have been considered at MAX-IV in recent...
A uniform distribution of nucleation tin sites is essential to the growth of high quality Nb3Sn thin film by vapor diffusion method. The less-nuclear zones were commonly observed in previous nucleation experiments. However, a fully understanding of the occurrence of less-nuclear zones has not yet been achieved. Here, the adsorption energy of nuclear agent SnCl2 on different crystal planes of...
Optical Stochastic Cooling (OSC) was recently demonstrated at Fermilab’s Integrable Optics Test Accelerator (IOTA) storage ring. This demonstration marked the first realization of the stochastic cooling (SC) principle in the optical regime and achieved a system bandwidth of approximately 20 THz, more than three orders of magnitude greater than state-of-the-art SC systems. The initial...
Nb3Sn thin films are mainly used on superconducting radio frequency (SRF) cavities, single-photon detectors and RF logic circuits. Copper-based Nb3Sn thin-film SRF (TFSRF) cavities are promising for particle accelerators because they may combine the advantages of high thermal conductivity and high gradient. In this paper, a bronze method, including multi-layer deposition and heat treatment,...
The RAON accelerator facility which is under construction in South Korea consists of many subsystems. These subsystems have many control devices such as Programmable Logic Controller, Power Supply, Motor, and FPGA. In order to integrate these devices into the main control system, the RAON integrated control system consists of three parts which are the main control room, server & storage...
The RF group constructed a second radio frequency (RF) system for the Taiwan Photon Source (TPS) RF system. This RF system employs a high-power RF transmitter to deliver RF energy to the cavity. The RF transmitter is composed of multiple power supply modules (PSMs) that are installed in series. PSMs are critical and fragile components of the RF transmitter.
This article presents the...
The Hefei Advanced Light Facility (HALF) storage ring will be an ultralow emittance storage ring with 2.2 GeV beam energy, less than 100 pm·rad emittance, 480 m circumference and 350 mA nominal current, which is designed with 20-long and 20-middle straights, so more insertion devices can be installed for users. To facilitate its high performance, the beam-coupling impedance effect must be...
Superconducting (SC) undulators composed of high-temperature superconducting (HTS) tapes, which can be applied to compact light sources such as a table-top free-electron laser, are a part of research and development projects at Karlsruhe Institute of Technology (KIT). In order to minimize the beam heat loads in a cryostat including the compact SC planar undulator, a vacuum chamber (liner)...
The Mainz Energy-Recovering Superconducting Accelerator (MESA), an energy-recovering (ER) LINAC, is currently under construction at the Institute for Nuclear physics at the Johannes Gutenberg-Universität Mainz, Germany. In the ER mode continues wave (CW) beam is accelerated from 5 MeV up to 105 MeV. The energy gain of the beam is provided through 2 enhanced ELBE-type cryomodules containing two...
The study and understanding of collective effects plays a vital role for fourth-generation light sources. These effects mostly need to be mitigated and controlled to achieve the design operational parameters. However, they can also be utilized to gain insights into the properties of the machine.
While the 3 GeV storage ring at the MAX IV light source is running in multi-bunch mode during user...
The existing code for particle scattering and tracking in collimation systems integrated in SixTrack, called K2, was migrated from the current software in FORTRAN, to a new Python/C interface integrated in the Xsuite tracking code that is being developed at CERN. This is an essential step towards a full integration of collimation studies using Xtrack, and will allow profiting from GPU...
Optimization and design of particle accelerators is challenging due to the large number of free parameters and the corresponding lack of gradient information available to the optimizer. Thus, full optimization of large beamlines becomes infeasible due to the exponential growth of free parameter space the optimization algorithm must navigate. Providing exact or approximate gradient information...
The transfer line that carries the electron beam from the plasma to the undulators is certainly a critical line in EuPRAXIA@SPARC_LAB as in all plasma driven Free Electron Lasers.
This machine section must serve multiple purposes: capturing the highly divergent bunches at the plasma exit, separating the driver bunch from the witness and finally matching the witness to the FEL undulators....
An upgrade project is ongoing at Elettra Sincrotrone Trieste for a 4th-generation storage ring light source called Elettra 2.0. The new machine poses new challenges in terms of performance of the accelerator and sub-systems. One concern, currently under investigation, is about the effects of the passive superconducting third harmonic cavity on the stored beam due to the presence of a dark gap...
The quest of laser plasma accelerators is of great interest for various applications such as light sources or high energy physics colliders. This research has led to numerous performance improvements, particularly in terms of beam energy versus compactness [1] and ultra-short bunch length [2]. However, these performances are often reached without the achievement of sufficient beam quality,...
After the LHC Injectors Upgrade (LIU) project, the CERN Proton Synchrotron Booster (PSB) operates with a new injection kinetic energy of 160 MeV and an extraction energy of 2 GeV. In light of this, several measurements have been performed to characterize the behaviour of the accelerator in terms of beam stability and beam coupling impedance in the new energy range. In particular, the...
The growth time of transverse coupled-bunch instability (TCBI) in the vertical direction was
measured at SuperKEKB rings. Resistive wall (RW) impedance is the primary source of driving
TCBI. As a collider, special vacuum chambers are remarkable sources of RW impedance in
addition to RW impedance from regular chambers. Such chambers include collimators where the
chamber gap is very small...
The International Muon Collider Collaboration is currently investigating the possibility to build a muon collider with a center of mass energy of 3 TeV in a first phase, with an option to build a 10 TeV collider in a second phase. The muon beam decay is the global challenge of such a collider and fast acceleration is required to reach high luminosities. A series of three or four Rapid Cycling...
In the framework of the International Muon Collider Collaboration, a 10 TeV muon collider ring is being studied, with the option of an intermediate 3 TeV collider stage. The decay of high-energy muons represents a great challenge in terms of heat load management and radiation shielding for the superconducting magnets of the collider ring. Materials such as tungsten are being considered to...
Several studies have been performed in the 2021 and 2022 runs to build a better understanding of the behaviour of the accelerator with high intensity beams. Transverse beam instabilities at injection energy are known from previous measurements and simulations to be a potential limitation to reach the LHC Injectors Upgrade (LIU) target beam intensity. This paper summarizes the limitations...
The Karlsruhe Research Accelerator (KARA), the storage ring at KIT, allows short electron bunch operation with positive as well as negative momentum compaction factor. For both cases, the beam dynamics are studied. Using a line array camera KALYPSO (KArlsruhe Linear arraY detector for MHz rePetition rate SpectrOscopy), based on TI-LGAD, the horizontal intensity distribution of the emitted...
Coherent Synchrotron Radiation (CSR) occurs when electron beams traverse a curved trajectory. In novel accelerators, CSR poses a potential limit for electron beams to reach high brightness. While the longitudinal CSR wake has been well studied in one-dimensional theory and implemented in several simulation codes, transverse wakefields have received less attention. Following the recently...
The tracking code RF-Track has been updated to include a large set of single-particle and collective effects: beam loading in standing and travelling wave structures, coherent and incoherent synchrotron radiation, intra-beam scattering, multiple Coulomb scattering in materials, and particle lifetime. This new set of effects was focused on the simulation of high-intensity machines such as...
The lattice design process for BESSY III is based on a systematic & deterministic approach where sub-structures of the MBA lattice are analyzed and optimized before the lattice is composed. During this process, 5 standardized Higher-Order-Multi-Bend-Achromat (HO-6MBA) lattices were developed utilizing different combinations of homogeneous and gradient bends in the unit and the dispersion...
A high-density temperature and X-ray mapping system has been developed.
The X-ray mapping system, which uses strips with 32 channels of X-ray sensors, is now ready for use. The current sensor chip was selected about 10 years ago for Nb cavities operating at 2K, but recent advances in SRF cavities have required detection at higher temperatures, such as 20K for Nb3Sn materials. The current...
The Rapid Cycling Synchrotron (RCS) in China Spallation Neutron Source (CSNS) is a high intensity proton accelerator, the impedance can drive collective instabilities and limit the machine performance. Due to new component installation, the impedance model should be updated. A thorough estimation of the coupling impedance is presented and the impedance model in the RCS is obtained.
New S-band disk-loaded TM01-2pi/3-travelling-wave structures and pulse compressors have been developed for upgrades of the injector linac for SuperKEKB and Photon-factory storage rings in KEK. The structures 2-m long have ingenious disk irises with oval fillets reducing discharge in high-power operation and modulations in radius suppressing beam break-up instabilities arising from HEM11...
The main ring (MR) of the Japan proton accelerator research complex (J-PARC) delivers the high-intensity proton beams to the T2K long-baseline neutrino experiment. To observe charge-conjugation and parity-transformation violation in the lepton sector with high accuracy, the upgrade of the MR toward the beam power of 1.3 MW is mandatory. One promising method for increasing the beam power is to...
Volume and precision are tightly related to magnetic components that are typically necessary in a power converter for filtering (inductor) or voltage adaptation (transformer) purposes.
This paper presents a methodology for creating an efficient design tool for magnetic components to be used in power electronics applications. Specifically, an air cored inductor is taken as an example. The...
The relatively high transition temperature of A15 superconducting materials makes them a potential alternative to Nb for radio-frequency applications. We present PVD deposition of one A15 material, V$_3$Si, on Cu and sapphire substrates. The surface structure and composition of the films were characterised via SEM and EDX. The superconducting properties were investigated using a field...
The storage ring of the High Energy Photon Source will be driven by five higher-order-mode-damped 166.6 MHz beta=1 quarter-wave superconducting cavities operating at 4 K. Three prototype cavities were manufactured in Beijing and the surface preparations were conducted in Ningxia and Beijing. The cavities were subsequently vertical tested at PAPS in Huairou (Beijing). The cavity Q0...
Developing HTS dipole inserts producing fields larger than 5 T within 15 T Nb3Sn outserts is necessary to generate 20 T or higher fields for future high energy colliders. Dipole inserts based on the cos-theta coil geometry with various stress management concepts and Bi2212 super-conducting strand and cable are being developed at Fermilab both within and beyond the U.S. national effort. On...
Superconducting radio-frequency cavities made out of niobium form the fundamental block of modern particle accelerators. A model proposed by Gurevich [1] suggests the use of a superconductor-insulator-superconductor (SIS) structure to achieve higher accelerating fields and a reduced surface resistance beyond the thermodynamic limits of Nb. As a first step to pursue this approach, a single-cell...
