MO3 — Monday Session 3 (12-Sep-22 16:30—18:00)
Chair: U. Iriso, ALBA-CELLS, Cerdanyola del Vallès, Spain
Paper
Title
Page
MO3I1
Review of BPM Drift Effects and Compensation Schemes
G. Rehm
HZB, Berlin, Germany
Apart from short term BPM resolution (repeatability), which aims at a few nm / sqrt(Hz) in modern systems, medium to long-term drift over durations of seconds to weeks (reproducibility) represents one of the challenges for BPM electronic developments. A number of approaches and compensation schemes have been developed and tested during the past years (e.g. cross-bar switching, pilot tone compensation, active temperature stabilization etc.) and experience has been gathered with environmental effects on electronics, cables and connectors. This talk will provide a review of drift effects and mitigation schemes for the next generation BPM systems.
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Diamond-II Electron Beam Position Monitor Development
168
L.T. Stant, M.G. Abbott, L. Bobb, G. Cook, L. Hudson, A.F.D. Morgan, E.P.J. Perez Juarez, A.J. Rose, A. Tipper
DLS, Oxfordshire, United Kingdom
The UK national synchrotron facility, Diamond Light Source, is preparing for a major upgrade to the accelerator complex. Improved beam stability requirements necessitate the fast orbit feedback system be driven from beam position monitors with lower noise and drift performance than the existing solution. Short-term beam motion must be less than 2 nm/sqrt(Hz) over a period of one second with a data rate of 100 kHz, and long-term peak-to-peak beam motion must be less than 1 µm. A new beam position monitor is under development which utilises the pilot-tone correction method to reduce front-end and cabling perturbations to the button signal; and a MicroTCA platform for digital signal processing to provide the required data streams. This paper discusses the challenges faced during the design of the new system and presents experimental results from testing on the existing machine.
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Pulse-by-Pulse Photon Beam Position Measurements at the SPring-8 Undulator Beamline
173
H. Aoyagi, T. Fujita, K. Kobayashi, H. Osawa, S. Takahashi
JASRI/SPring-8, Hyogo, Japan
Funding:This work is partly supported by Japan Society for the Promotion of Science through a Grant-in-Aid for Scientific Research (c), No.18K11943, 21K12530. This study analyzes a pulse-mode x-ray beam position monitor that enables pulse-by-pulse position measurement in a synchrotron radiation beamline of the synchrotron radiation facility, SPring-8. The monitor is equipped with blade-shaped detection elements utilizing diamond heatsinks to reduce stray capacitance and a microstripline transmission line to improve high-frequency characteristics. The detection elements operate as photocathodes and generate single unipolar pulses with a full width at half-maximum of less than 1 ns, allowing pulse-by-pulse measurement of the synchrotron radiation beam. We confirmed the basic operation of the monitor at the SPring-8 bending magnet beamline*. The detection element’s heat resistance consequently improved. An evaluation test was carried out at the SPring-8 undulator beamline with significantly high synchrotron radiation intensity. We aim to report the evaluation results of the sensitivity and resolution of the monitor measured by exciting a betatron oscillation in the horizontal/vertical direction using beam shakers of the SPring-8 storage ring and the observation results of the pulse-by-pulse photon beam dynamics induced by beam injection. * https://journals.aps.org/prab/pdf/10.1103/PhysRevAccelBeams.24.032803
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Beam Position Monitoring of Multi-bunch Electron Beams at the FLASH Free Electron Laser
177
N. Baboi, H.T. Duhme, B. Lorbeer
DESY, Hamburg, Germany
The superconducting FLASH user facility (Free electron LASer in Hamburg) accelerates 10 electron bunch trains per second, which are mostly used to produce high brilliance XUV and soft X-ray pulses. Each train usually contains up to 600 electron bunches with a typical charge between 100 pC and 1 nC and a minimum bunch spacing of 1 us. Various types of beam position monitors (BPM) are built in three electron beam lines, having a single bunch resolution of 2-100 um rms. This paper presents multi-bunch position measurements for various types of BPMs and built in at various locations. The dependency of the resolution on the beam offset is also shown.
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