Measurements of the micro-spill structure of medical cyclotron and synchrotron beams and its impact on pulse pileup
Abstract
Detector characterization and instrumentation testing are often performed at cyclotron and synchrotron facilities, many of which were originally developed for medical applications in cancer therapy. For particle physics experiments requiring a single-particle resolution, pileup can significantly degrade data quality, making precise knowledge of the beam time structure essential for selecting appropriate readout parameters. However, such information is often unavailable from the facilities and challenging to determine experimentally. Here, we report measurements of the spill time structure at two medical accelerator facilities using a silicon carbide (SiC) particle sensor coupled to a high-frequency readout system. Owing to its high carrier saturation velocity and the tolerance to large bias voltages, SiC is well suited for fast readout and measurements requiring precise timing. Using a 6 GHz readout with custom SiC diodes, we characterize the micro-spill structure of both cyclotron and synchrotron beams on a sub-nanosecond timescale. The measured arrival-time distributions exhibit modulation with the accelerator RF frequencies, reflecting features of the extraction process. The resolved micro-spill structure enables quantitative estimation of pileup contributions and provides design constraints for future readout electronics. The presented results emphasize the importance of the characterization of the beam time-structure characterization for the development of precise readout systems.
Versions
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BibTeX
@misc{knopf2026measurements,
title = {{Measurements of the micro-spill structure of medical cyclotron and synchrotron beams and its impact on pulse pileup}},
author = {Matthias Knopf and Simon Waid and Stefan Gundacker and Sebastian Onder and Daniel Radmanovac and Philipp Gaggl and Giulio Bordieri and Francesco Cordoni and Marta Missiaggia and Enrico Verroi and Giulio Magrin and Thomas Bergauer and Albert Hirtl},
howpublished = {arXiv},
year = {2026},
month = jul,
doi = {10.48550/arxiv.2605.07508},
eprint = {2605.07508},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.07508},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Measurements of the micro-spill structure of medical cyclotron and synchrotron beams and its impact on pulse pileup
AU - Matthias Knopf
AU - Simon Waid
AU - Stefan Gundacker
AU - Sebastian Onder
AU - Daniel Radmanovac
AU - Philipp Gaggl
AU - Giulio Bordieri
AU - Francesco Cordoni
AU - Marta Missiaggia
AU - Enrico Verroi
AU - Giulio Magrin
AU - Thomas Bergauer
AU - Albert Hirtl
PY - 2026
DA - 2026/07/24
PB - arXiv
DO - 10.48550/arxiv.2605.07508
UR - https://arxiv.org/abs/2605.07508
AB - Detector characterization and instrumentation testing are often performed at cyclotron and synchrotron facilities, many of which were originally developed for medical applications in cancer therapy. For particle physics experiments requiring a single-particle resolution, pileup can significantly degrade data quality, making precise knowledge of the beam time structure essential for selecting appropriate readout parameters. However, such information is often unavailable from the facilities and challenging to determine experimentally. Here, we report measurements of the spill time structure at two medical accelerator facilities using a silicon carbide (SiC) particle sensor coupled to a high-frequency readout system. Owing to its high carrier saturation velocity and the tolerance to large bias voltages, SiC is well suited for fast readout and measurements requiring precise timing. Using a 6 GHz readout with custom SiC diodes, we characterize the micro-spill structure of both cyclotron and synchrotron beams on a sub-nanosecond timescale. The measured arrival-time distributions exhibit modulation with the accelerator RF frequencies, reflecting features of the extraction process. The resolved micro-spill structure enables quantitative estimation of pileup contributions and provides design constraints for future readout electronics. The presented results emphasize the importance of the characterization of the beam time-structure characterization for the development of precise readout systems.
ER -