IPAC'25 - the 16th International Particle Accelerator Conferece

Novel statistical measurement of longitudinal beam halo in the Fermilab Recycler using a μTCA FPGA system

THPM091

5 Jun 2025, 15:30

2h

Exhibiton Hall A _Magpie (TWTC)

Poster Presentation MC6.T03 Beam Diagnostics and Instrumentation Thursday Poster Session

Speaker

Ryan Hensley (University of California, Davis)

Description

The formation of non-Gaussian halo in both the transverse and longitudinal dimensions of beam bunches has been notoriously difficult to model and measure. We present a novel technique to measure the longitudinal halo of 2.5 MHz bunches (400 ns) in the Fermilab Recycler. Out-of-time beam is a critical issue for Mu2e, as it can introduce unwanted backgrounds that compromise the experiment’s precision.
Our measurement utilizes a new μTCA-based FPGA system for data acquisition and signal processing, enabling precise, high-speed measurements of scattered beam particles. A small fraction of the beam is scattered from an ion chamber in the M3 transfer beamline between the Recycler Ring and the Delivery Ring, which is detected by a charge telescope composed of quartz Cherenkov radiators and photomultiplier tubes. By integrating data over many revolutions, the time profile of the longitudinal halo (out-of-time beam) can be resolved to fractional levels below ${10}^{-5}$ relative to the in-time beam. These results are compared with simulations to validate models of halo formation and beam dynamics, providing critical input for optimizing beam delivery to Mu2e.

Funding Agency

Department of Energy grant DE-SC0009999