Beam Loss Monitors and Machine Protection
Paper Title Page
TUAO02 Diagnostics for Collimator Irradiation Studies in the Advanced Photon Source Storage Ring 26
 
  • J.C. Dooling, W. Berg, M. Borland, J.R. Calvey, G. Decker, L. Emery, K.C. Harkay, R.R. Lindberg, A.H. Lumpkin, G. Navrotski, V. Sajaev, J.B. Stevens, Y.P. Sun, K.P. Wootton, A. Xiao
    ANL, Lemont, Illinois, USA
 
  Funding: Work supported by the U.S. D.O.E.,Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02- 06CH11357
The Advanced Photon Source (APS) is building a fourth-generation storage ring (4GSR), replacing the present double-bend achromat lattice with a multibend achromat system thereby allowing the production of ultra-bright x-ray beams. The new lattice enables a two-order-of-magnitude reduction in horizontal beam emittance and a factor of two increase in beam current. The result is an electron beam of very high energy- and power-densities. Initial predictions suggest virtually any material struck by the undiluted electron beam will be damaged. Two experimental beam abort studies have been conducted on collimator test pieces in the present APS SR to inform the design of a fully-functional machine protection system for APS 4GSR operations at 200 mA. A comprehensive suite of diagnostics were employed during the studies The diagnostics used in these experiments are not new, but employed in different ways to obtain unique data sets. With these data sets now in hand, we are developing new numerical tools to guide collimator design.
 
video icon
        Right click on video for
Picture-in-Picture mode
or Full screen display.

At start the sound is muted!
 
slides icon Slides TUAO02 [26.053 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2020-TUAO02  
About • paper received ※ 03 September 2020       paper accepted ※ 15 September 2020       issue date ※ 30 October 2020  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUAO03
Ionization Chamber for Electron Beam Monitoring at Ultra High Dose Rate  
 
  • C. Lahaye, S. Salvador
    CNRS/IN2P3/LPC CAEN, Caen, France
  • J.-M. Fontbonne, J. Thariat
    LPC, Caen, France
 
  Ultra high dose rate (FLASH) electron beam therapy consists in treating tumors by delivering a dose above 1 Gy in pulse of 1 µs. Despite ionization chambers are reference detectors in dose monitoring, no real-time beam monitor based on ionization chambers exists for such ultra high dose rates. In this study, we present the response of an ionization chamber to ultra high dose rates. Simulations were performed to compute the current measured by a chamber using a 1D transport model. The transport equations included recombination*, electron capture [**,***] and electric field change due to space charge****. Simulations were compared to measurements performed using a 800 µm gap, 1 cm2 active surface ionization chamber irradiated by 5 MeV electron pulses up to 4 Gy/µs, and varying high voltage from 400 V/mm up to 1200 V/mm. Despite high recombination rates, the signal produced by the electrons moving in the chamber was proportional to the dose rate up to ~100 ns. Preliminary results suggest that a real-time dose measurement can be done by considering only the signal induced by the electrons. This opens the development for a real-time dose rate monitor based on ionization chambers.
*J. W. Boag et al 1996 Phys. Med. Biol. 41 885
**F. Di Martino et al 2005 Med. Phys. Vol.32, No 7
***K. Petersson et al 2017 Med. Phys. Vol.44, No 3
****M. Gotz et al 2017 Phys. Med. Biol. 62 8634
 
video icon
        Right click on video for
Picture-in-Picture mode
or Full screen display.

At start the sound is muted!
 
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPP04
Simulated Beam Loss Events in the FRIB Linac  
 
  • R. Shane, S. Cogan, S.M. Lidia
    FRIB, East Lansing, Michigan, USA
 
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
Beam loss is an ever-present issue in accelerators and can lead to degraded beam quality, activation, and machine damage. It is crucial to be able to pinpoint the source of beam loss so that the cause can be addressed. Towards this end, beam loss studies were performed at the Facility for Rare Isotope Beams (FRIB) in which beam spills were simulated at various locations within the accelerator. Beam spills were achieved by adjusting the magnetic fields or turning off selected RF cavities. This defocused or moved the beam such that particles impacted the walls, apertures, and other surfaces in the beam transport volume, creating measurable radiation. Losses were monitored on a suite of detectors including neutron detectors, pressurized ion chambers, and halo monitor rings. These data were used in conjunction with calculated beam profiles and statistical analyses in order to correlate loss detection patterns with beam spill location.
 
poster icon Poster TUPP04 [0.718 MB]  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPP05 X-Ray Beam Size Monitor Enclosure for the Advanced Photon Source Upgrade 34
 
  • K.P. Wootton, W.X. Cheng, G. Decker, S.H. Lee, B.X. Yang
    ANL, Lemont, Illinois, USA
 
  Funding: This research used resources of the Advanced Photon Source, operated for the U.S. Department of Energy Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.
Confirmation of pm rad scale emittances from the Advanced Photon Source Upgrade electron storage ring necessitates direct measurement of the electron beam size. In the present work, we motivate design choices for the X-ray beam size monitor shielding enclosure for the Advanced Photon Source Upgrade. Particular emphasis is given to outlining design choices from the perspectives of safety, overall project construction schedule and eventual beamline operations.
 
poster icon Poster TUPP05 [0.609 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2020-TUPP05  
About • paper received ※ 02 September 2020       paper accepted ※ 14 September 2020       issue date ※ 30 October 2020  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPP06 Investigation of an Optical-Fiber Based Beam Loss Monitor at the J-PARC Extraction Neutrino Beamline 110
 
  • S.V. Cao, M.L. Friend
    KEK, Tsukuba, Japan
 
  Optical fibers, which at once generate and guide Cherenkov light when charged particles pass through them, are widely used to monitor the beam loss at accelerator facilities. In this report, we investigate this application at the J-PARC extraction neutrino beamline, where a 30GeV proton beam with eight bunches of ~20ns (1σ) bunch width and 581ns bucket length, is extracted from the Main Ring, guided, and hit onto a graphite target to produce a highly intense beam of neutrinos. Three 30m-length 200um-core-diameter optical fibers, which are arranged flexibly to form 60m or 90m length fibers, were installed in the beamline. The beam loss signal was observed with the Muti-Pixel Photon Counters. We will discuss the result and prospects of using optical fibers for monitoring and locating the beam loss source.  
poster icon Poster WEPP06 [9.014 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2020-WEPP06  
About • paper received ※ 02 September 2020       paper accepted ※ 15 September 2020       issue date ※ 30 October 2020  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPP07 The Insertable Beam Stop in the ESS SPK Section 114
 
  • E.M. Donegani, T.J. Grandsaert, T.J. Shea, C.A. Thomas
    ESS, Lund, Sweden
 
  This paper deals with the Insertable Beam Stop (IBS) to be installed at the transition between the normal conducting and superconducting sections of the ESS linac. The IBS will be used to avoid beam losses in the cryogenic cavities during tuning and commissioning of the ESS linac. The IBS will stop protons in the energy range from 73 MeV to 92 MeV. The proton beam has a current up to 62.5 mA, and 50·10-6 or 5E-6s long pulses at a rate of 1 or 14 Hz, respectively. Firstly, the IBS was designed in MCNPX/ANSYS to withstand thermal and structural stresses, while minimizing neutron production and limiting the deposited power in the cryogenic cavities below 0.2 W/m. Secondly, the prompt background and residual dose in the vicinity of the IBS were computed, as well as the activation of the IBS components themselves. Finally, a feasibility study was performed to determine if the IBS can be profitably used as a beam-profile monitoring device. The results will serve as input for calculations of the expected signal in beam loss monitors. Moreover, they will enable the design of the nearby shielding limiting the activation of surrounding structures and allowing maintenance works.  
poster icon Poster WEPP07 [0.772 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2020-WEPP07  
About • paper received ※ 01 September 2020       paper accepted ※ 14 September 2020       issue date ※ 30 October 2020  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPP09
New Beam Loss Monitor System at SOLEIL  
 
  • N. Hubert, A. Bence, M. El Ajjouri, D. Pédeau
    SOLEIL, Gif-sur-Yvette, France
 
  SOLEIL has recently upgraded its Beam Loss Monitor (BLM) system from pin-diode detectors to plastic scintillators associated with photosensor modules. This new kind of monitor, associated to its dedicated electronics, is able to measure slow or fast losses. Monitors have been carefully calibrated with a Cesium source, and installed at systematic locations on the storage ring to provide reliable loss amplitude comparison between them. SOLEIL storage ring is now equipped with 80 BLMs. Installation setup, calibration procedure and resulting measurements will be presented.  
poster icon Poster WEPP09 [2.181 MB]  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPP10 Proton-Induced SEY From Beam Interceptive Devices in the ESS Linac 117
 
  • E.M. Donegani
    ESS, Lund, Sweden
 
  During the ESS linac commissioning, a wealth of beam-interceptive devices will be exposed to protons with nominal and non-nominal energies spanning from 75 keV to 2 GeV. Therefore, a database of proton-induced Secondary Emission Yield (SEY) values was prepared for the structural materials of insertable devices into the ESS linac. The database relies on calculations of stopping powers in MCNPX and the Sternglass theory applied to protons in the [1 keV, 2 GeV] energy range. Results are reported for 16 relevant materials to wire scanners, bunch shape monitors and target imaging systems, including: TZM, Ni, SiC and graphite of various densities. In the future, the results can be used also for determining the impact of secondaries on emittance or beam-current measurements with Emittance Monitor Units or Faraday cups of the ESS linac, respectively. Moreover, the database can be extended to critical structural materials of the ESS linac itself, in order to estimate the impact of secondary electrons on the overall beam quality.  
poster icon Poster WEPP10 [0.528 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2020-WEPP10  
About • paper received ※ 31 August 2020       paper accepted ※ 15 September 2020       issue date ※ 30 October 2020  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPP02
RMS-R3 - Radiation Hard System for Beam, Background and Luminosity Monitoring at the Upgraded LHCb Experiment  
 
  • V. Dobishuk, S. Chernyshenko, O. Okhrimenko, V.M. Pugatch
    NASU/INR, Kiev, Ukraine
  • F. Alessio
    CERN, Meyrin, Switzerland
 
  Funding: National Academy of Sciences of Ukraine
The results of a performance study of the upgraded Radiation Monitoring System (RMS-R3) for the LHCb experiment are presented. The RMS-R3 is built out of the eight Metal-Foil Detectors (MFD) placed at 2 m from IP-8 around the beam pipe in a backward hemisphere. The system is designed for monitoring beams interaction rate (relative luminosity) and background at the LHCb nominal instantaneous luminosity of p-p collisions 5 times increased in RUN3. The feasibility of monitoring of relative contribution from the beams luminous region (IP-8) and collimators is illustrated by the data accumulated with a similar RMS during RUN1 and RUN2 campaigns. An advantageous feature of the MFD, its high radiation tolerance of a GGy level, originates from the principle of its operation due to secondary electron emission from a surface of a metal sensor resulting in a positive charge in it which is readout by charge integrator. Simple structure of the detector modules, low operating voltage (about 20 volts), commercially available DAQ boards further improve their figure of merit. The RMS-R3 perfect linear response in a dynamical range of 1:100000 is demonstrated in tests with r/a source and X-rays.
 
poster icon Poster THPP02 [1.952 MB]  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPP04 Testbed Development for the Characterisation of an ASIC for Beam Loss Measurement Systems 215
 
  • F. Martina, L. Giangrande, J. Kaplon, P.V. Leitao, C. Zamantzas
    CERN, Geneva, Switzerland
  • F. Martina
    The University of Liverpool, Liverpool, United Kingdom
 
  A high-performance, radiation-hardened, application-specific integrated circuit (ASIC) is under development at CERN for digitising signals from beam losses monitoring systems in harsh radiation environments. To fully characterise and validate both the analogue and digital parts of these ASICs, an automated testbed has been developed. Here we report on the components used to build this setup, its capabilities as well as the methodology of the data analysis. Focus is given to the data collection, the automation and the efficient computation methods developed to extract the merit factors of two different ASIC designs from prototype manufacturing runs.  
poster icon Poster THPP04 [4.534 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2020-THPP04  
About • paper received ※ 11 September 2020       paper accepted ※ 17 September 2020       issue date ※ 30 October 2020  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)