IBIC2019 - Classification: Beam loss monitors and machine protection

Paper	Title	Page
MOBO04	Characterization and First Beam Loss Detection with One ESS-nBLM System Detector	29
	L. Segui, H. Alves, S. Aune, J. Beltramelli, Q. Bertrand, M. Combet, M. Kebbiri, Ph. Legou, O. Maillard, A. Marcel, T. Papaevangelou CEA-IRFU, Gif-sur-Yvette, France A. Dano-Daguze, D. Desforge, F. Gougnaud, T.J. Joannem, C. Lahonde-Hamdoun, P. Le Bourlout, Y. Mariette, J. Marroncle, V. Nadot, G. Tsiledakis CEA-DRF-IRFU, France I. Dolenc Kittelmann, T.J. Shea ESS, Lund, Sweden
	The monitoring of losses is crucial in any accelerator. In the new high intensity hadron facilities even low energy beam can damage or activate the materials so the detection of small losses in this region is very important. A new type of neutron beam loss monitor has been developed specifically targeting this region, where only neutrons and photons can be produced and where typical BLM, based on charged particle detection, could not be appropriate because of the photon background due to the RF cavities. The BLM proposed is based on gaseous Micromegas detectors, designed to be sensitive to fast neutrons and with little sensitivity to photons. Development of the detectors presented here has been done to fulfil the requirements of ESS and they will be part of the ESS-BI systems. The detector has been presented in previous editions of the conference. Here we focus on the neutron/gamma rejection with the final FEE and in the first operation of one of the modules in a beam during the commissioning of LINAC4 (CERN) with the detection of provoked losses and their clear separation from RF gammas. The ESS-nBLM system is presented in this conference in a separate contribution.
	Slides MOBO04 [7.609 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOBO04
About •	paper received ※ 05 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019
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MOPP006	Commissioning of the Beam Loss Monitoring system for the HADES beam-line at GSI	74
	P. Boutachkov, S. Damjanovic, M. Sapinski, B. Walasek-Höhne GSI, Darmstadt, Germany
	The High Acceptance Di-Electron Spectrometer experiments at GSI (HADES) require high-intensity heavy ion beams. Monitoring and minimization of the beam losses are critical for the operation at the desired beam intensities. FAIR-type Beam Loss Monitor (BLM) system based on sixteen plastic scintillator detectors is installed along the beam line from the SIS-18 synchrotron to the experiment location. The detectors are used in counting mode, with maximum counting rate of order of 20 MHz. The system has been commissioned during the 2018 beam time. Details on the detector setup, its calibration procedure and how it can be used for quantitative beam loss determination are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP006
About •	paper received ※ 04 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019
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MOPP016	Particle interactions with diamond detectors	115
	C. Weiss, M. Cerv, E. Griesmayer, P. Kavrigin CIVIDEC Instrumentation, Wien, Austria
	Chemical vapor deposition (CVD) diamond as radiation detector material has a wide range of applications, in par- ticular for harsh radiation environments and at high tem- peratures. The sensitivity of diamond is exploited in meas- urements with charged particles, neutrons and photons. Diamond detectors are used as beam loss monitors in particle accelerators, for photon detection in Synchrotron Light Sources, for neutron diagnostics in thermal neutron fields and for Deuterium-Deuterium (D-D) fusion and Deuterium-Tritium (D-T) fusion plasma neutrons. In this paper we present the simulated and measured re- sponse functions of single-crystal (sCVD) diamond detec- tors to charged particles, heavy ions, thermal neutrons, fast neutrons, X-rays and gamma radiation. All measurements were performed with CIVIDEC diamond detectors and re- lated electronics [1] at various research facilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP016
About •	paper received ※ 09 September 2019 paper accepted ※ 10 September 2019 issue date ※ 10 November 2019
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MOPP017	New Beam Loss Monitor System at SOLEIL	118
	N. Hubert, M. El Ajjouri, D. Pédeau SOLEIL, Gif-sur-Yvette, France
	SOLEIL is currently upgrading 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, can be used to record slow or fast losses. Monitors have been calibrated with a diode and with a Cesium source. Both methods are compared. After preliminary tests, a first set of 20 new BLMs have been installed on 2 cells of the storage ring. Installation setup, calibration procedure and first measurements will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP017
About •	paper received ※ 04 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019
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MOPP019	Development and Evaluation of an Alternative Sensor Lifetime Enhancement Technique Used with the Online-Radiation-Monitoring System (DosiMon) at the European XFEL at DESY, Hamburg	122
	F. Schmidt-Föhre, S. Arab, D. Nölle, R. Susen DESY, Hamburg, Germany
	The European XFEL (E-XFEL), that started operation in September 2017 at the DESY/XFEL site in Hamburg/Germany uses a single-tunnel concept, forcing all frontend machine devices and electronics to be located inside the accelerator tunnel. Electro-magnetic showers, mainly produced by gun dark-current, RF cavity field-emission and beam-losses expose these devices to damaging irradiation. The new Online-Radiation-Monitoring-System (DosiMon) is mainly used for surveillance of radiation sensitive permanent magnet structures, diagnostic devices and rack-housed electronics. The integrated dose from Gamma- and optional future Neutron-radiation measurements can be monitored online by the DosiMon system. Safety limits ensure the correct function of monitored devices, provided by lifecycle estimations as measures for on time part exchange, to prevent significant radiation damage. A first expansion state currently enables more than 500 gamma measuring points. The development of a new sensor lifetime enhancement technique for the utilized RadFet sensors is presented together with corresponding evaluation measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP019
About •	paper received ※ 04 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019
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MOPP020	First Tests Using Sipm Based Beam Loss Monitors at the European XFEL	127
	T. Wamsat, P.A. Smirnov DESY, Hamburg, Germany
	The European XFEL MTCA based Beam Loss Monitor System (BLM) is composed of about 450 monitors using photomultiplier tubes (PMTs). BLMs installed in the SASE undulator intersections show high signals at electron energy higher 16 GeV or photon energy higher 14 keV due to background synchrotron radiation which directly affects the PMT. The amplitude of this signal can get that high that, also without using any scintillating material, the BLMs get blind for real losses. Also different lead arrangements did not shield the signal sufficiently. First tests show that a Silicon photomultiplier (SiPM) is not affected. Also there are several advantages to use SiPM, they are cheaper by factor of 40 and operating voltage is below 45V. First test will be presented and how it can get implemented in the existing BLMs and BLM system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP020
About •	paper received ※ 04 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019
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MOPP022	Neutron Sensitive Beam Loss Monitoring System for the ESS Linac	131
	I. Dolenc Kittelmann, F.S. Alves, E.C. Bergman, C.S. Derrez, V. Grishin, K.E. Rosengren, T.J. Shea ESS, Lund, Sweden Q. Bertrand, T.J. Joannem, Ph. Legou, Y. Mariette, V. Nadot, T. Papaevangelou, L. Segui CEA-IRFU, Gif-sur-Yvette, France W. Cichalewski, G.W. Jabłoński, W. Jałmużna, R. Kiełbik TUL-DMCS, Łódź, Poland
	The European Spallation Source, currently under construction in Lund, Sweden, will be a neutron source based on partly superconducting linac, accelerating protons to 2GeV with a peak current of 62.5mA, ultimately delivering a 5MW beam to a rotating tungsten target. For a successful tuning and operation of a linac, a Beam Loss Monitoring (BLM) system is required. The system is designed to protect the machine from beam-induced damage and unnecessary activation of the components. This contribution focuses on one of the BLM systems to be deployed at the ESS linac, namely the neutron sensitive BLM (nBLM). Recently, test of the nBLM data acquisition chain including the detector has been performed at LINAC4, at CERN. The test represents first evaluation of the system prototype in realistic environment. Results of the test will be presented together with an overview of the ESS nBLM system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP022
About •	paper received ※ 04 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019
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MOPP023	Ionisation Chamber Based Beam Loss Monitoring System for the ESS Linac	136
	I. Dolenc Kittelmann, F.S. Alves, E.C. Bergman, C.S. Derrez, T.J. Grandsaert, V. Grishin, T.J. Shea ESS, Lund, Sweden W. Cichalewski, G.W. Jabłoński, W. Jałmużna, R. Kiełbik TUL-DMCS, Łódź, Poland
	The European Spallation Source, currently under construction in Lund, Sweden, will be a neutron source based on partly superconducting linac, accelerating protons to 2GeV with a peak current of 62.5mA, ultimately delivering a 5MW beam to a rotating tungsten target. One of the most critical elements for the protection of an accelerator is its Beam Loss Monitoring (BLM) system. The system is designed to protect the machine from beam-induced damage and unnecessary activation of the components. This contribution focuses on one of the BLM systems to be deployed at the ESS linac, namely the Ionisation Chamber based BLM (ICBLM). Several test campaigns have been performed at various facilities. Results of these tests will be presented here together with an overview of the ESS ICBLM system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP023
About •	paper received ※ 04 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019
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MOPP024	Development of New Loss Monitor Electronics for the HIPA Facility	141
	R. Dölling, E. Johansen, W. Koprek, D. Llorente Sancho, M. Roggli PSI, Villigen PSI, Switzerland
	A replacement for the ageing electronics of loss monitors at HIPA is under development. We discuss requirements, concepts and first tests of a prototype.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP024
About •	paper received ※ 04 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019
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MOPP025	Enhancements to the SNS* Differential Current Monitor to Minimize Errant Beam	146
	W. Blokland ORNL, Oak Ridge, Tennessee, USA C.C. Peters, T.B. Southern ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The existing Differential Beam Current Monitor (DBCM) has been modified to not only compare beam current waveforms between upstream and downstream locations, but also to compare the previous beam current waveform with the incoming beam current waveform. When there is an unintended change in the beam current, the DBCM now aborts the beam to prevent beam loss on the next pulse. This addition has proved to be crucial to allow beam during specific front-end problems. All data is saved when an abort is issued for post-mortem analy-sis. This paper describes the additions to the implementa-tion, our operational experience, and future plans for the differential beam current monitor.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP025
About •	paper received ※ 04 September 2019 paper accepted ※ 10 September 2019 issue date ※ 10 November 2019
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TUAO01	Beam Diagnostics for Studying Beam Losses in the LHC	222
	B. Salvachua CERN, Meyrin, Switzerland
	The LHC is well covered in terms of beam loss instrumentation. Close to 4000 ionisation chambers are installed to measure global beam losses all around the LHC ring, and diamond detectors are placed at specific locations to measure bunch-by-bunch losses. Combining the information of these loss detectors with that from additional instrumentation, such as current transformers, allows for enhanced understanding and control of losses. This includes a fast and reliable beam lifetime calculation, the identification of the main origin of the loss (horizontal or vertical betatron motion or off-momentum), or a feedback to perform controlled off-momentum loss maps to validate the settings of the collimation system. This paper describes the diagnostic possibilities that open up when such measurements from several systems are combined. This is proposed as an Invited presentation from CERN Beam Instrumentation Group.
	Slides TUAO01 [9.161 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUAO01
About •	paper received ※ 04 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019
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TUAO02	Beam-Loss Detection for LCLS-II	229
	A.S. Fisher, C.I. Clarke, B.T. Jacobson, R.A. Kadyrov, E. Rodriguez, L. Sapozhnikov, J.J. Welch SLAC, Menlo Park, California, USA
	SLAC is now installing LCLS-II, a superconducting electron linac driven by continuous RF at 1.3 GHz. The 4-GeV, 120-kW beam has a maximum rate of nearly 1 MHz and can be switched pulse-by-pulse to either of two undulators, to generate hard and soft x rays. Two detector types measure beam losses. Point beam-loss monitors (PBLMs) set limits at critical loss points: septa, beam stoppers and dumps, halo collimators, protection collimators (which normally receive no loss), and zones with weak shielding. PBLMs are generally single-crystal diamond detectors, except at the gun, where a scintillator on a PMT is more sensitive to the low-energy (1 MeV) beam. Long beam-loss monitors (LBLMs) use 200-m lengths of radiation-hard optical fiber, each coupled to a PMT, to capture Cherenkov light from loss showers. LBLMs protect the entire 4-km path from gun to beam dump and locate loss points. In most regions two fibers provide redundancy and view the beam from different angles. Loss signals are integrated with a 500-ms time constant and compared to a threshold; if exceeded, the beam is stopped within 0.2 ms. We report on our extensive tests of the detectors and the front-end signal processing.
	Slides TUAO02 [4.268 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUAO02
About •	paper received ※ 03 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019
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TUAO03	Beam Loss Measurements Using the Cherenkov Effect in Optical Fiber for the BINP e⁻e⁺ Injection Complex	233
	Yu.I. Maltseva, A.R. Frolov, V.G. Prisekin BINP SB RAS, Novosibirsk, Russia
	Optical fiber based beam loss monitor (OFBLM) has been developed for the 500 MeV BINP Injection Complex (IC). Such monitor is useful for accelerator commissioning and beam alignment, and allows real-time monitoring of e⁻e⁺ beam loss position and intensity. Single optical fiber (OF) section can cover the entire accelerator instead of using a large number of local beam loss monitors. In this paper brief OFBLM selection in comparison with other distributed loss monitors was given. Methods to improve monitor spatial resolution are discussed. By selecting 45 m long silica fiber (with a large core of 550 um) and microchannel plate photomultiplier (MCP-PMT), less than 1 m spatial resolution can be achieved.
	Slides TUAO03 [3.053 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUAO03
About •	paper received ※ 05 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019
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TUAO04	Commissioning of the ARIEL E-LINAC Beam Loss Monitor System	238
	M. Alcorta, A.D. D’Angelo, D. Dale, H. Hui, B. Humphries, S.R. Koscielniak, K. Langton, A. Lennarz, R.B. Nussbaumer, T. Planche, M. Rowe, S.D. Rädel TRIUMF, Vancouver, Canada
	The commissioning of the Advanced Rare Isotope & Electron Linac (ARIEL) facility at TRIUMF is underway. The 30 MeV e-linac has successfully been commissioned to 100 W, and to further increase the power to 1 kW the beam loss monitor system (BLM) for fast Machine Protection must be fully operational. There are currently two types of BLMs employed in the e-linac; long-ionization chambers (LIC) and scintillators, consisting of a small BGO coupled to a PMT. A front-end beam loss monitor board was designed at TRIUMF to meet the strict requirements of the BLMs: a trip of the beam occurs on 100 nC in 100 ms of integrated beam loss, and the trip must occur in < 10 us. This contribution will report on the status of the 1 kW BLM system commissioning and will give an outlook as the power is increased to the full 300 kW.
	Slides TUAO04 [14.621 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUAO04
About •	paper received ※ 04 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019
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Paper

Title

Page

Characterization and First Beam Loss Detection with One ESS-nBLM System Detector

29

L. Segui, H. Alves, S. Aune, J. Beltramelli, Q. Bertrand, M. Combet, M. Kebbiri, Ph. Legou, O. Maillard, A. Marcel, T. Papaevangelou
CEA-IRFU, Gif-sur-Yvette, France
A. Dano-Daguze, D. Desforge, F. Gougnaud, T.J. Joannem, C. Lahonde-Hamdoun, P. Le Bourlout, Y. Mariette, J. Marroncle, V. Nadot, G. Tsiledakis
CEA-DRF-IRFU, France
I. Dolenc Kittelmann, T.J. Shea
ESS, Lund, Sweden

The monitoring of losses is crucial in any accelerator. In the new high intensity hadron facilities even low energy beam can damage or activate the materials so the detection of small losses in this region is very important. A new type of neutron beam loss monitor has been developed specifically targeting this region, where only neutrons and photons can be produced and where typical BLM, based on charged particle detection, could not be appropriate because of the photon background due to the RF cavities. The BLM proposed is based on gaseous Micromegas detectors, designed to be sensitive to fast neutrons and with little sensitivity to photons. Development of the detectors presented here has been done to fulfil the requirements of ESS and they will be part of the ESS-BI systems. The detector has been presented in previous editions of the conference. Here we focus on the neutron/gamma rejection with the final FEE and in the first operation of one of the modules in a beam during the commissioning of LINAC4 (CERN) with the detection of provoked losses and their clear separation from RF gammas. The ESS-nBLM system is presented in this conference in a separate contribution.

Slides MOBO04 [7.609 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOBO04

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paper received ※ 05 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019

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MOPP006

Commissioning of the Beam Loss Monitoring system for the HADES beam-line at GSI

74

P. Boutachkov, S. Damjanovic, M. Sapinski, B. Walasek-Höhne
GSI, Darmstadt, Germany

The High Acceptance Di-Electron Spectrometer experiments at GSI (HADES) require high-intensity heavy ion beams. Monitoring and minimization of the beam losses are critical for the operation at the desired beam intensities. FAIR-type Beam Loss Monitor (BLM) system based on sixteen plastic scintillator detectors is installed along the beam line from the SIS-18 synchrotron to the experiment location. The detectors are used in counting mode, with maximum counting rate of order of 20 MHz. The system has been commissioned during the 2018 beam time. Details on the detector setup, its calibration procedure and how it can be used for quantitative beam loss determination are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP006

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paper received ※ 04 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019

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MOPP016

Particle interactions with diamond detectors

115

C. Weiss, M. Cerv, E. Griesmayer, P. Kavrigin
CIVIDEC Instrumentation, Wien, Austria

Chemical vapor deposition (CVD) diamond as radiation detector material has a wide range of applications, in par- ticular for harsh radiation environments and at high tem- peratures. The sensitivity of diamond is exploited in meas- urements with charged particles, neutrons and photons. Diamond detectors are used as beam loss monitors in particle accelerators, for photon detection in Synchrotron Light Sources, for neutron diagnostics in thermal neutron fields and for Deuterium-Deuterium (D-D) fusion and Deuterium-Tritium (D-T) fusion plasma neutrons. In this paper we present the simulated and measured re- sponse functions of single-crystal (sCVD) diamond detec- tors to charged particles, heavy ions, thermal neutrons, fast neutrons, X-rays and gamma radiation. All measurements were performed with CIVIDEC diamond detectors and re- lated electronics [1] at various research facilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP016

About •

paper received ※ 09 September 2019 paper accepted ※ 10 September 2019 issue date ※ 10 November 2019

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MOPP017

New Beam Loss Monitor System at SOLEIL

118

N. Hubert, M. El Ajjouri, D. Pédeau
SOLEIL, Gif-sur-Yvette, France

SOLEIL is currently upgrading 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, can be used to record slow or fast losses. Monitors have been calibrated with a diode and with a Cesium source. Both methods are compared. After preliminary tests, a first set of 20 new BLMs have been installed on 2 cells of the storage ring. Installation setup, calibration procedure and first measurements will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP017

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paper received ※ 04 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019

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MOPP019

Development and Evaluation of an Alternative Sensor Lifetime Enhancement Technique Used with the Online-Radiation-Monitoring System (DosiMon) at the European XFEL at DESY, Hamburg

122

F. Schmidt-Föhre, S. Arab, D. Nölle, R. Susen
DESY, Hamburg, Germany

The European XFEL (E-XFEL), that started operation in September 2017 at the DESY/XFEL site in Hamburg/Germany uses a single-tunnel concept, forcing all frontend machine devices and electronics to be located inside the accelerator tunnel. Electro-magnetic showers, mainly produced by gun dark-current, RF cavity field-emission and beam-losses expose these devices to damaging irradiation. The new Online-Radiation-Monitoring-System (DosiMon) is mainly used for surveillance of radiation sensitive permanent magnet structures, diagnostic devices and rack-housed electronics. The integrated dose from Gamma- and optional future Neutron-radiation measurements can be monitored online by the DosiMon system. Safety limits ensure the correct function of monitored devices, provided by lifecycle estimations as measures for on time part exchange, to prevent significant radiation damage. A first expansion state currently enables more than 500 gamma measuring points. The development of a new sensor lifetime enhancement technique for the utilized RadFet sensors is presented together with corresponding evaluation measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP019

About •

paper received ※ 04 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019

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MOPP020

First Tests Using Sipm Based Beam Loss Monitors at the European XFEL

127

T. Wamsat, P.A. Smirnov
DESY, Hamburg, Germany

The European XFEL MTCA based Beam Loss Monitor System (BLM) is composed of about 450 monitors using photomultiplier tubes (PMTs). BLMs installed in the SASE undulator intersections show high signals at electron energy higher 16 GeV or photon energy higher 14 keV due to background synchrotron radiation which directly affects the PMT. The amplitude of this signal can get that high that, also without using any scintillating material, the BLMs get blind for real losses. Also different lead arrangements did not shield the signal sufficiently. First tests show that a Silicon photomultiplier (SiPM) is not affected. Also there are several advantages to use SiPM, they are cheaper by factor of 40 and operating voltage is below 45V. First test will be presented and how it can get implemented in the existing BLMs and BLM system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP020

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paper received ※ 04 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019

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MOPP022

Neutron Sensitive Beam Loss Monitoring System for the ESS Linac

131

I. Dolenc Kittelmann, F.S. Alves, E.C. Bergman, C.S. Derrez, V. Grishin, K.E. Rosengren, T.J. Shea
ESS, Lund, Sweden
Q. Bertrand, T.J. Joannem, Ph. Legou, Y. Mariette, V. Nadot, T. Papaevangelou, L. Segui
CEA-IRFU, Gif-sur-Yvette, France
W. Cichalewski, G.W. Jabłoński, W. Jałmużna, R. Kiełbik
TUL-DMCS, Łódź, Poland

The European Spallation Source, currently under construction in Lund, Sweden, will be a neutron source based on partly superconducting linac, accelerating protons to 2GeV with a peak current of 62.5mA, ultimately delivering a 5MW beam to a rotating tungsten target. For a successful tuning and operation of a linac, a Beam Loss Monitoring (BLM) system is required. The system is designed to protect the machine from beam-induced damage and unnecessary activation of the components. This contribution focuses on one of the BLM systems to be deployed at the ESS linac, namely the neutron sensitive BLM (nBLM). Recently, test of the nBLM data acquisition chain including the detector has been performed at LINAC4, at CERN. The test represents first evaluation of the system prototype in realistic environment. Results of the test will be presented together with an overview of the ESS nBLM system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP022

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paper received ※ 04 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019

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MOPP023

Ionisation Chamber Based Beam Loss Monitoring System for the ESS Linac

136

I. Dolenc Kittelmann, F.S. Alves, E.C. Bergman, C.S. Derrez, T.J. Grandsaert, V. Grishin, T.J. Shea
ESS, Lund, Sweden
W. Cichalewski, G.W. Jabłoński, W. Jałmużna, R. Kiełbik
TUL-DMCS, Łódź, Poland

The European Spallation Source, currently under construction in Lund, Sweden, will be a neutron source based on partly superconducting linac, accelerating protons to 2GeV with a peak current of 62.5mA, ultimately delivering a 5MW beam to a rotating tungsten target. One of the most critical elements for the protection of an accelerator is its Beam Loss Monitoring (BLM) system. The system is designed to protect the machine from beam-induced damage and unnecessary activation of the components. This contribution focuses on one of the BLM systems to be deployed at the ESS linac, namely the Ionisation Chamber based BLM (ICBLM). Several test campaigns have been performed at various facilities. Results of these tests will be presented here together with an overview of the ESS ICBLM system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP023

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paper received ※ 04 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019

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MOPP024

Development of New Loss Monitor Electronics for the HIPA Facility

141

R. Dölling, E. Johansen, W. Koprek, D. Llorente Sancho, M. Roggli
PSI, Villigen PSI, Switzerland

A replacement for the ageing electronics of loss monitors at HIPA is under development. We discuss requirements, concepts and first tests of a prototype.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP024

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paper received ※ 04 September 2019 paper accepted ※ 08 September 2019 issue date ※ 10 November 2019

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MOPP025

Enhancements to the SNS* Differential Current Monitor to Minimize Errant Beam

146

W. Blokland
ORNL, Oak Ridge, Tennessee, USA
C.C. Peters, T.B. Southern
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
The existing Differential Beam Current Monitor (DBCM) has been modified to not only compare beam current waveforms between upstream and downstream locations, but also to compare the previous beam current waveform with the incoming beam current waveform. When there is an unintended change in the beam current, the DBCM now aborts the beam to prevent beam loss on the next pulse. This addition has proved to be crucial to allow beam during specific front-end problems. All data is saved when an abort is issued for post-mortem analy-sis. This paper describes the additions to the implementa-tion, our operational experience, and future plans for the differential beam current monitor.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP025

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paper received ※ 04 September 2019 paper accepted ※ 10 September 2019 issue date ※ 10 November 2019

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TUAO01

Beam Diagnostics for Studying Beam Losses in the LHC

222

B. Salvachua
CERN, Meyrin, Switzerland

The LHC is well covered in terms of beam loss instrumentation. Close to 4000 ionisation chambers are installed to measure global beam losses all around the LHC ring, and diamond detectors are placed at specific locations to measure bunch-by-bunch losses. Combining the information of these loss detectors with that from additional instrumentation, such as current transformers, allows for enhanced understanding and control of losses. This includes a fast and reliable beam lifetime calculation, the identification of the main origin of the loss (horizontal or vertical betatron motion or off-momentum), or a feedback to perform controlled off-momentum loss maps to validate the settings of the collimation system. This paper describes the diagnostic possibilities that open up when such measurements from several systems are combined.
This is proposed as an Invited presentation from CERN Beam Instrumentation Group.

Slides TUAO01 [9.161 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUAO01

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paper received ※ 04 September 2019 paper accepted ※ 09 September 2019 issue date ※ 10 November 2019

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TUAO02

Beam-Loss Detection for LCLS-II

229

A.S. Fisher, C.I. Clarke, B.T. Jacobson, R.A. Kadyrov, E. Rodriguez, L. Sapozhnikov, J.J. Welch
SLAC, Menlo Park, California, USA

SLAC is now installing LCLS-II, a superconducting electron linac driven by continuous RF at 1.3 GHz. The 4-GeV, 120-kW beam has a maximum rate of nearly 1 MHz and can be switched pulse-by-pulse to either of two undulators, to generate hard and soft x rays. Two detector types measure beam losses. Point beam-loss monitors (PBLMs) set limits at critical loss points: septa, beam stoppers and dumps, halo collimators, protection collimators (which normally receive no loss), and zones with weak shielding. PBLMs are generally single-crystal diamond detectors, except at the gun, where a scintillator on a PMT is more sensitive to the low-energy (1 MeV) beam. Long beam-loss monitors (LBLMs) use 200-m lengths of radiation-hard optical fiber, each coupled to a PMT, to capture Cherenkov light from loss showers. LBLMs protect the entire 4-km path from gun to beam dump and locate loss points. In most regions two fibers provide redundancy and view the beam from different angles. Loss signals are integrated with a 500-ms time constant and compared to a threshold; if exceeded, the beam is stopped within 0.2 ms. We report on our extensive tests of the detectors and the front-end signal processing.

Slides TUAO02 [4.268 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUAO02

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paper received ※ 03 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019

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TUAO03

Beam Loss Measurements Using the Cherenkov Effect in Optical Fiber for the BINP e⁻e⁺ Injection Complex

233

Yu.I. Maltseva, A.R. Frolov, V.G. Prisekin
BINP SB RAS, Novosibirsk, Russia

Optical fiber based beam loss monitor (OFBLM) has been developed for the 500 MeV BINP Injection Complex (IC). Such monitor is useful for accelerator commissioning and beam alignment, and allows real-time monitoring of e⁻e⁺ beam loss position and intensity. Single optical fiber (OF) section can cover the entire accelerator instead of using a large number of local beam loss monitors. In this paper brief OFBLM selection in comparison with other distributed loss monitors was given. Methods to improve monitor spatial resolution are discussed. By selecting 45 m long silica fiber (with a large core of 550 um) and microchannel plate photomultiplier (MCP-PMT), less than 1 m spatial resolution can be achieved.

Slides TUAO03 [3.053 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUAO03

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paper received ※ 05 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019

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TUAO04

Commissioning of the ARIEL E-LINAC Beam Loss Monitor System

238

M. Alcorta, A.D. D’Angelo, D. Dale, H. Hui, B. Humphries, S.R. Koscielniak, K. Langton, A. Lennarz, R.B. Nussbaumer, T. Planche, M. Rowe, S.D. Rädel
TRIUMF, Vancouver, Canada

The commissioning of the Advanced Rare Isotope & Electron Linac (ARIEL) facility at TRIUMF is underway. The 30 MeV e-linac has successfully been commissioned to 100 W, and to further increase the power to 1 kW the beam loss monitor system (BLM) for fast Machine Protection must be fully operational. There are currently two types of BLMs employed in the e-linac; long-ionization chambers (LIC) and scintillators, consisting of a small BGO coupled to a PMT. A front-end beam loss monitor board was designed at TRIUMF to meet the strict requirements of the BLMs: a trip of the beam occurs on 100 nC in 100 ms of integrated beam loss, and the trip must occur in < 10 us. This contribution will report on the status of the 1 kW BLM system commissioning and will give an outlook as the power is increased to the full 300 kW.

Slides TUAO04 [14.621 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUAO04

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paper received ※ 04 September 2019 paper accepted ※ 07 September 2019 issue date ※ 10 November 2019

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