Beam Position Monitors (BPMs) are the most commonly used non-destructive diagnostics for almost all linear accelerators, cyclotrons, and synchrotrons. It is very important for BPM to provide accurate beam position for closed-orbit correction, and etc. Meanwhile, it is necessary to accurately offline calibrate the BPM position sensitivity and evaluate whether the result is correct or not. In...
A bead test was conducted to measure the shunt impedance (R/Q) of the cavity beam position monitor (BPM) for PAL-XFEL. R/Q is an important parameter of a cavity BPM because it relates to the signal strength, which determines the resolution of the beam position measurement. In the bead test, a dielectric and metal bead were used to assess the frequency change at various bead positions. The...
DALI is an envisioned suite of advanced accelerator-based THz sources that are continuously tunable over the frequency range from 0.1 THz to 30 THz. The THz sources will provide radiation with high pulse energy (up to 100 µJ – 1 mJ) at a high but flexible repetition rate up to 1 MHz. An MeV ultra-fast electron diffraction (UED) source will complement this facility.
The contribution will...
By directly sampling the BPM signals with a high sampling rate oscilloscope, the bunch-by-bunch position and phase were calculated. With the help of injection trigger signal, oscilloscope was utilized to capture the injection process. The energy mismatch of the injection transient process and the residual oscillation of the injection bunch were studied. The longitudinal tune and oscillation...
As part of the ongoing ALBA II upgrade, which aims to significantly enhance the performance of the ALBA Synchrotron Light Source, a new design for button Beam Position Monitors (BPMs) is under investigation. In this contribution, we present the results of a characterization study conducted on button prototypes supplied by two different manufacturers. Furthermore, we introduce the preliminary...
Laser-based electro-optic detection (EOD) has been a valuable tool to measure the longitudinal electron bunch shape with sub-ps resolution for almost a decade, but it has always been a tool for expert use. Recently, the server and the user interface has been updated allow automated laser locking, time calibration and measurements to prepare for general operator use at the EuXFEL. It is...
We present preliminary experimental results on the measurement of the current profile and longitudinal phase space (LPS) of an ultrarelativistic electron beam using a corrugated structure at the Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL). The electron bunch is streaked by the transverse wakefield induced by the corrugated plates, resulting in a correlation between the...
EuPRAXIA@SPARC_LAB is a FEL user-facility currently under construction at INFN-LNF in the framework of the EuPRAXIA collaboration. The electron beam will be accelerated to 1 GeV by an X-band RF linac followed by a plasma wakefield acceleration stage. This high-brightness linac requires diagnostic tools able to measure the beam parameters with high accuracy and resolution. To monitor the beam...
The AWAKE 150 MeV electron beamline at CERN is used to provide a witness bunch for plasma wakefield acceleration, with a bunch length shorter than the plasma wavelength to ensure efficient capture and acceleration. To accomplish this, a real-time, non-invasive bunch length monitor is essential. A monitor is being studied to calculate the RMS bunch length by measuring coherent Cherenkov...
We have developed a Stripline BPM readout device based on an AMD/Xilinx RFSoC chip which integrates multiple ADCs, DACs, a large scale FPGA, and an ARM processor in a single package. The developed device is intended for use at the beam transfer line connecting the KEK injector Linac to the SuperKEKB collider rings. SuperKEKB will operate at unprecedented luminosities requiring very high beam...
As part of the CSNS-II upgrade, an improved injection scheme will be implemented to mitigate the space charge effect. To precisely measure the transverse beam position during injection, painting, and storage in the Rapid Cycling Synchrotron (RCS), a large-aperture (260 mm × 180 mm) Beam Position Monitor (BPM) is essential. The rectangular cut-plane BPM was selected for its excellent linearity...
A new BPM processor is being developed to address the ageing of BPM signal processors and the new demand for synchronised data acquisition at the storage ring of Shanghai Synchrotron Radiation Facility (SSRF). The BPM processor consists primarily of a digital carrier board and an analog front-end (AFE) module. The AFE is responsible for the conditioning of the BPM output RF signal and for the...
PAL-XFEL plans to begin double-bunch operation in 2027, with two electron bunches separated by 25 ns. The existing beam position monitor (BPM) electronics were designed for single-bunch operation, so the two signals overlap and bias the position measurement. To support this mode without modifying the electronics, we developed an external radio-frequency (RF) switch-based bunch selector that...
SenSiC GmbH, a spin-off from the Swiss Light Source (SLS), has developed a new class of beamstopper sensors, termed Beamstopper Integrated Sensors (BIS)[1,2], based on Silicon Carbide (SiC) semiconductor technology. Using custom processing and assembly methods, BIS devices achieve ultra-compact footprints below 1 mm and are designed for both real-time intensity monitoring and four-quadrant...
We present an improved electro-optic sampling technique that extends the sensitivity and temporal resolution of beam diagnostics beyond conventional limits. Through precise calibration of the detection system, we reconstruct the spatio-temporal profile of the near-field generated by a relativistic electron beam in a ZnTe crystal. This allows for accurate retrieval of the beam’s peak current...
A test bench for commissioning the 324 MHz RF deflectors used in BSMs has been in use for the upgrade project CSNS-II linac. The pulsed 10keV electron beam produced by a Kimball focusable electron gun has been captured by a YAG:Ce screen and imaged by an industrial camera installed vertically right above the view port of the screen after passing through the body of the RF deflector...
In modern low-emittance electron storage rings, precise beam orbit control is crucial to ensure the beam passes through the magnetic center of each high-gradient multipole magnet, with an accuracy of 10 μm or even better. Accurate alignment of a BPM with the center of the neighboring magnet is imperative, a critical requirement for SPring-8-II. With a total of 340 BPMs, efficient beam...
Electro-optic (EO) diagnostics offer non-destructive methods to resolve the longitudinal charge profile of highly relativistic bunches without the need for complex calibrations or ambiguous phase recovery techniques. The most common technique, EO spectral decoding (EOSD), is favoured for its simplicity, reliability, and straightforward output interpretation, however its resolution is...
We present signal and thermal measurements from the first prototype of a stripline Beam Position Monitor (BPM) intended for the PETRA IV synchrotron ring [1]. The monitor was installed at the PETRA III testbed for evaluation and compared against CST Studio Suite [2] simulation results. Initial measurements revealed unexpected signal oscillations and significant heating (up to 135 °C), which...
In scanning transmission X-ray microscopy (STXM) beamlines, precise control of X-ray beam position and intensity (I₀) is crucial to minimize imaging artefacts and improve spectral quality. However, limited working distances in STXM setups restrict the integration of conventional diagnostics. To address this, we have developed a center-stop-based Silicon Carbide (SiC) device that integrates...
A Feschenko-style Bunch Shape Monitor (BSM) was used to measure the longitudinal profile of H- bunches at the Los Alamos Neutron Science Center (LANSCE) accelerator. The measurements were taken in the 201.25-MHz drift tube linac (DTL), where the design beam energy is 72.72 MeV. The results of the measurements are presented, and several unexpected features of the measurements are discussed.
At the heavy ion accelerator UNILAC at GSI Helmholtz Center for Heavy Ion Research in Darmstadt, measurements were carried out with a Fast Faraday Cup (FFC) in order to precisely measure the time structure of the particle beam. The FFC offers a highly accurate time-resolved recording of the charge distribution along the longitudinal beam profile. The data obtained in combination with a dipole...
The high-precision energy spectrometry system, as a key electron beam diagnostic, enables accurate measurement of beam energy distribution and supports injector performance optimization. Beam collimation prior to the system affects measurement accuracy. For electron injectors operating at a few MeV, a high-precision spectrometry system based on the magnetic deflection method is developed, and...
Solid State X-ray beam position monitors (XBPMs) are an established reality for in-line, real-time monitoring for X-ray beams. Commercial products are available in different materials, such as diamond (CIVIDEC, DECTRIS) and Silicon Carbide (SenSiC GmbH)*. One issue related to this class of devices is the presence of a separation cross in the center of the device, used to obtain four...
The Electron-Ion Collider is being constructed at the Brookhaven National Laboratory. The crab cavities will be utilized for the increase of the luminosity. While the initial set-up of crab cavities can be based on the orbit measurements during dedicated development time, we need to utilize a less invasive approach for monitoring the longitudinal beam tilt during operations. We propose to...
Modern BPM processors utilize digital processing of the beam induced signals. The information on the signal amplitudes is used for the delta over sum calculation of the beam position, while the readily available phase information is usually discarded. We have experimentally tested measurement of the individual positions of two beams propagating in the common beampipe utilizing both phase and...
Diamond-II is a major upgrade to the current synchrotron
facility, Diamond Light Source. The low emittance electron
beam requires more stable, low drift beam position mon-
itor electronics which are also essential for the Fast Orbit
Feedback system. This paper presents simulated results of
the analog frontend for the electron beam position monitors.
This work aims to deliver an analog...
In the framework of the recent FLASH2020+ upgrade program, the longitudinal electron beam diagnostics of the FLASH accelerator had been modernized and extended by additional devices, including an electro-optical bunch length detector (EOD[1]), as well as an additional bunch compression monitor (BCM [2]) and a bunch arrival-time monitor (BAM [3]) in the new direct seeding beamline FLASH1. ...
For the HESR diagonally cut BPMs were designed, with 64 manufactured and tested with a purpose-built BPM test-stand. This test-stand had to host BPMs of various lengths, the overall length of the complete vacuum system varies from 450 mm to 1585 mm. For all BPMs several properties, e.g. the geometric factors or the electrical center in relation to the geometric center, were measured utilizing...
The development of longitudinal diagnostics for short-pulse electron accelerators is challenging but necessary to provide high-brightness electron bunches. This is equally true in novel plasma accelerators and for free electron lasers. The gold standard for such measurements is the transverse deflecting cavity (TDC); however, these devices are typically invasive and costly to produce and...
SOLEIL II is the low emittance upgrade project for Synchrotron SOLEIL, targeting an emittance of ~80 pm.rad.
The new lattice includes 196 Beam Position Monitors (BPM) distributed in 3 different types depending on the vacuum chamber diameter.
To ensure consistent signal levels across varying pipe diameters, two button sizes were selected: 6 mm diameter for 16 mm beam pipes, and 7 mm diameter...
Our heavy ion beams are slow, short, and thick. For such beams, spiral beam position monitors(BPMs) are expected to provide good linearity and multiple information readouts despite their small size. At the RIKEN Nishina Center, various ion beams are accelerated using linacs and cyclotrons. However, the beams handled are slow enough compared to relativistic speeds, the bunch length is only...
PERLE is an Energy-Recovery Linac (ERL) to be constructed at IJCLab in Orsay. It will be the First multi-turn ERL with superconducting RF (SRF) with the ambition to reach 10MW beam operation (20mA beam current and 500MeV beam energy)
Diagnostics are a key element for PERLE operation and among diagnostics, the salient feature for Beam position monitors (BPMs) is the presence of multiple beams...
The XBPM installed in the TPS frontend determines the center position of the photon beam using four CVD diamond blades. The combination of XBPM and upstream/downstream EBPM readings of the insertion device enables verification of the photon beam’s alignment along the correct trajectory. Significant changes in the beam position or profile, as well as prolonged periods without recalibration, may...
This paper reports on the design and operational experience of an electro optical sampling (EOS) diagnostics based on the same femtosecond laser used for the seeding process of the FERMI FEL2. This design allows operating in parallel with the FEL2, minimizing time jitter with respect to the seed laser which is the main time marker of the FEL process by removing the time jitter contributions...
In this study we present an extensive theoretical investigation, and lateral resolution optimization, into the use of semiconductor-based sensors (semicon-sensors) for real-time monitoring of high-intensity synchrotron whitebeams. Leveraging internal photoemission, these sensors can give critical advantages over conventional metal-based blade monitors that rely on *surface...
We report progress on a THz streaking experiment at the UCLA Pegasus Laboratory enabling femtosecond-resolution electron bunch length measurements. Single-cycle, 50 µJ THz pulses centered at 0.6 THz are coupled into a metallic horn structure, enhancing field strengths to several hundred MV/m while simultaneously establishing boundary conditions for a strong streaking gradient. A...
The FELiChEM is a user facility dedicated for energy chemistry research, developed at University of Science and Technology of China in Hefei. The beam position diagnostics system at FELiChEM are upgraded recently. The facility operates with a special mode: macropulses at 1 Hz repetition rate with microsecond duration, each containing micropluses at 59.5 MHz repetition rate. The key advancement...
