IPAC2015 - List of Keywords (beam-losses)

Paper	Title	Other Keywords	Page
MOPJE032	A Steering Study for the ESS Normal Conducting Linac	DTL, linac, quadrupole, lattice	351
	R. Miyamoto ESS, Lund, Sweden
	Construction of the European Spallation Source is rapidly progressing in Lund, Sweden, and preparations for commissioning of its proton linac has been underway for some time now. Accurate adjustment of accelerator components to achieve ideal beam parameters is the key to maximizing performance and safe operation for any machine. This paper presents a study of beam steering for the normal conducting part of the proton linac of ESS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE032
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MOPMA014	Design of Superconducting CW linac for PIP-II	linac, cryomodule, optics, operation	565
	A. Saini, V.A. Lebedev, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Proton Improvement Plan (PIP) -II is a proposed roadmap to upgrade existing proton accelerator complex at Fermilab. It is primarily based on construction of superconducting (SC) linear accelerator (linac) that would be capable to operate in continuous wave (CW) mode. This paper will present reference design of SC linac and discuss motivations and requirements resulting in this layout and beam optics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA014
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MOPTY034	Distributed Beam Loss Monitor Based on the Cherenkov Effect in Optical Fiber	electron, radiation, positron, storage-ring	1004
	Yu. Maltseva, F.A. Emanov, A.V. Petrenko, V.G. Prisekin BINP SB RAS, Novosibirsk, Russia F.A. Emanov NSU, Novosibirsk, Russia A.V. Petrenko CERN, Geneva, Switzerland
	A distributed beam loss monitor based on the Cherenkov effect in optical fiber has been implemented for the VEPP5 electron and positron linacs and the 510 MeV damping ring at the Budker INP. The monitor operation is based on detection of the Cherenkov radiation generated in optical fiber by means of relativistic particles created in electromagnetic shower after highly relativistic beam particles (electrons or positrons) hit the vacuum pipe. The main advantage of the distributed monitor compared to local ones is that a long optical fiber section can be used instead of a large number of local beam loss monitors. In our experiments the Cherenkov light was detected by photomultiplier tube (PMT). Timing of PMT signal gives the location of the beam loss. In the experiment with 20 m long optical fiber we achieved 3 m spatial resolution. To improve spatial resolution optimization and selection process of optical fiber and PMT are needed and according to our theoretical estimations 0.5 m spatial resolution can be achieved. We also suggest similar techniques for detection of electron (or positron) losses due to Touschek effect in storage rings.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPTY034
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MOPTY055	Beam Loss Monitoring for Run 2 of the LHC	monitoring, injection, detector, database	1057
	M.K. Kalliokoski, B. Auchmann, B. Dehning, F.S. Domingues Sousa, E. Effinger, J. Emery, V. Grishin, E.B. Holzer, S. Jackson, B. Kolad, E. Nebot Del Busto, O. Picha, C. Roderick, M. Sapinski, M. Sobieszek, C. Zamantzas CERN, Geneva, Switzerland
	The Beam Loss Monitoring (BLM) system of the LHC consists of over 3600 ionization chambers. The main task of the system is to prevent the superconducting magnets from quenching and protect the machine components from damage, as a result of critical beam losses. The BLM system therefore requests a beam abort when the measured dose in the chambers exceeds a threshold value. During Long Shutdown 1 (LS1) a series of modifications were made to the system. Based on the experience from Run 1 and from improved simulation models, all the threshold settings were revised, and modified where required. This was done to improve the machine safety at 7 TeV, and to reduce beam abort requests when neither a magnet quench or damage to machine components is expected. In addition to the updates of the threshold values, about 800 monitors were relocated. This improves the response to unforeseen beam losses in the millisecond time scale due to micron size dust particles present in the vacuum chamber. This contribution will discuss all the changes made to the BLM system, with the reasoning behind them.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPTY055
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MOPTY057	Feasibility Study of Monitoring the Population of the CERN-LHC Abort Gap with Diamond Based Particle Detectors	detector, monitoring, kicker, simulation	1065
	O. Stein, F. Burkart, B. Dehning, R. Schmidt, C.B. Sørensen, D. Wollmann CERN, Geneva, Switzerland
	At the end of a physics fill and in case of a failure, the LHC beams must be extracted and transferred through a 750m long line to the beam dump block. During the rise of the extraction kickers to their full strength a particle-free abort gap, with a length of 3 us in the LHC filling pattern, is required to prevent beam losses that could lead to substantial quenching of magnets, with a risk of damage. Therefore the particle population in the abort gap, which is mainly due to un-bunched beam, is monitored. Above a certain threshold an active cleaning by excitation of betatron oscillations with the transverse feedback system is initiated. This paper describes a novel method of monitoring the abort gap population using diamond particle detectors for detecting the interactions of beam in the abort gap with neon gas, injected in the beam pipe. Two different layouts of the system and the expected interaction and detection rates are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPTY057
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MOPTY058	Response of Polycrystalline Diamond Particle Detectors Measured with a High Intensity Electron Beam	detector, electron, experiment, radiation	1069
	O. Stein, F. Burkart, B. Dehning, R. Schmidt, C.B. Sørensen, D. Wollmann CERN, Geneva, Switzerland E. Griesmayer CIVIDEC Instrumentation, Wien, Austria
	Comprehensive understanding of beam losses in the LHC is required to ensure full machine protection and efficient operation. The existing BLM system using ionization chambers is not adequate to resolve losses with a time resolution below some 10 us. Ionization chambers are also not adequate to measure very large transient losses, e.g. beam impacting on collimators. Diamond particle detectors with bunch-by-bunch resolution have therefore been used in LHC to measure fast particle losses with a time resolution down to a level of single bunches. Diamond detectors have also successfully been used for material damage studies in other facilities, e.g. HiRadMat at the CERN-SPS. To fully understand their potential, such detectors were characterized with an electron beam at the BTF in LNF INFN Italy, with bunch intensities from 10³ to 10⁹ electrons. The detector response and efficiency has been measured with a 50 Ω and a 1 Ω read-out system. This paper describes the experimental setup and the results of the experiment. In particular, the responses of three samples of 100 um single-crystalline diamond detectors and two samples of 500 um polycrystalline diamond detectors are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPTY058
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MOPWI033	Advantages to an Online Multi-particle Beam Dynamics Model for High-power Proton Linacs	linac, operation, emittance, proton	1234
	L. Rybarcyk, S.A. Baily, X. Pang LANL, Los Alamos, New Mexico, USA
	High-power proton linacs like the 800-MeV LANSCE accelerator typically use a physics-based approach and online single-particle and envelope beam dynamics models to establish nominal set points for operation. However, these models are not good enough to enable immediate transition to high-power operation. Instead, some amount of empirical adjustment is necessary to achieve stable, low beam-loss operation. At Los Alamos, we have been developing a new online model, which employs multiparticle beam dynamics, as a tool for providing more information and insight to the operations staff, especially during this transition to high-power operations. This presentation will discuss some of the advantages and benefits of using this type of tool in the tune-up and operation of a high-power proton linac.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI033
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TUBC1	Recent Progress and Operational Status of the Compact ERL at KEK	laser, operation, quadrupole, experiment	1359
	S. Sakanaka, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondou, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sasaki, K. Satoh, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida KEK, Ibaraki, Japan E. Cenni Sokendai, Ibaraki, Japan R. Hajima, S. Matsuba, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma JAEA, Ibaraki-ken, Japan J.G. Hwang KNU, Deagu, Republic of Korea M. Kuriki Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan Y. Seimiya HU/AdSM, Higashi-Hiroshima, Japan
	Funding: Work supported by the Photon and Quantum Basic Research Coordinated Development Program from the MEXT, and by the MEXT grant for promoting technology for nuclear security. The Compact Energy Recovery Linac (cERL) is a superconducting test accelerator aimed at establishing technologies for the ERL-based future light source. After its construction during 2009 to 2013, the first CW beams of 20 MeV were successfully transported through the recirculation loop in February 2014. Then, initial tuning of beams and evaluations of beam properties were carried out. From September to December in 2014, we are constructing a Laser Compton Scattering (LCS) source* which aims at demonstrating technology for the future high-flux quasi-monochromatic gamma-ray source. In the next run of the cERL, which begins at the end of January 2015, we plan such works as an increase in the beam current (from 10 uA to 100 uA), commissioning of the LCS source, and sustained tuning of beams for lower emittance. We will report up-to-date results of these developments. * N. Nakamura et al., IPAC2014, MOPRO110; S. Sakanaka et al., LINAC14, TUPOL01. ** R. Nagai et al., IPAC2014, WEPRO003.
	Slides TUBC1 [2.679 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUBC1
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TUPWA017	Collimation scheme for the ESRF Upgrade	lattice, radiation, collimation, shielding	1434
	R. Versteegen, P. Berkvens, N. Carmignani, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, S.M. White ESRF, Grenoble, France
	The ultra low emittance foreseen for the ESRF Upgrade will translate into a limited Touschek lifetime, increasing substantially the loss rate around the ring compared to the present machine. Consequently it becomes crucial to know the distribution of electron beam losses to optimize the radiation shielding and to protect the insertion devices from radiation damage. Such loss maps of the storage ring can be produced thanks to the simulation of the Touschek scattering process along the lattice. It is shown that about 80 % of the beam losses can be collimated in a few chosen locations only, keeping the resulting lifetime reduction smaller than 10 %.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA017
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TUPJE066	Development of an Abort Kicker at APS to Mitigate Beam Loss-induced Quenches of the Superconducting Undulator	kicker, injection, septum, simulation	1787
	K.C. Harkay, J.C. Dooling, Y. Ivanyushenkov, R. Laird, F. Lenkszus, C.C. Putnam, V. Sajaev, J. Wang ANL, Argonne, Ilinois, USA
	Funding: Work supported by U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. The first superconducting undulator (SCU0) at the Advanced Photon Source (APS) has been delivering 80-100 keV photons for user science since January 2013. SCU0 often quenches during beam dumps triggered by the machine protection system (MPS). SCU0 typically recovers quickly after a quench, but SCU1, a second, longer device to be installed in 2015, may take longer to recover. We tested using injection kickers as an abort system to dump the beam away from SCU0 and the planned location of SCU1. An alternate trigger was tested that fires the kickers with MPS. We demonstrated that controlling the beam dump location with kickers can significantly reduce the beam losses at SCU0, as measured by fiber optic (FO) beam loss monitors (BLMs), and can also prevent a quench. A dedicated abort kicker system has been developed based on elegant simulations. A spare injection kicker was modified to produce the required waveform. Injection kicker tests, simulations, and the abort kicker design are described. Demonstration of this strategy in APS has implications for the APS Upgrade, where more SCUs are planned.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE066
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TUPTY045	Interactions between Macroparticles and High-Energy Proton Beams	proton, electron, simulation, vacuum	2112
	S. Rowan, A. Apollonio, B. Auchmann, A. Lechner, O. Picha, W. Riegler, H. Schindler, R. Schmidt, F. Zimmermann CERN, Geneva, Switzerland
	A known threat to the availability of the LHC is the interaction of macroparticles (dust particles) with the LHC proton beam. At the foreseen beam energy of 6.5 TeV during Run 2, quench margins in the superconducting magnets will be 2-3 times lower, and beam losses due such interactions may result in magnet quenches. The study introduce an improved numerical model of such interactions, as well as Monte-Carlo simulations that give the probability that such events will result in a beam-dump during Run 2.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY045
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TUPTY053	Roadmap towards High Accelerator Availability for the CERN HL-LHC Era	luminosity, radiation, operation, target	2143
	A. Apollonio, M. Brugger, L. Rossi, R. Schmidt, B. Todd, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland
	High Luminosity-LHC is the future upgrade of the LHC that aims at delivering an integrated luminosity of 3000 fb-1 over about 10 years of operation, starting from 2025. Significant modifications [1] will be implemented to accelerator systems, including new superconducting magnets, crab cavities, superconducting links, new collimators and absorbers based on advanced materials and design and additional cryo-plants. Due to the limit imposed by the number of simultaneous events at the experiments (pile-up) on peak luminosity, the latter will be levelled to 5*1034 cm^-2s⁻¹. The target integrated luminosity can only be achieved with a significant increase of the total available time for beam collisions compared to the 2012 LHC run, despite a beam current that is planned to double the nominal 0.58 A. Therefore one of the key figures of merit to take into account for system upgrades and new designs is their impact on the accelerator availability. In this paper the main factors affecting LHC availability will be discussed and predictions on the impact of future system upgrades on integrated luminosity presented. Requirements in terms of the maximum allowed number of dumps for the main contributing systems to LHC unavailability will be derived.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY053
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THPF095	Limits on Failure Scenarios for Crab Cavities in the HL-LHC	simulation, luminosity, optics, collimation	3923
	A. Santamaría García, H. Burkhardt, A. Macpherson, K.N. Sjobak, D. Wollmann, B. Yee-Rendón CERN, Geneva, Switzerland K. Hernandez-Chahin DCI-UG, León, Mexico B. Yee-Rendón CINVESTAV, Mexico City, Mexico
	The High Luminosity (HL) LHC upgrade aims for a tenfold increase in integrated luminosity compared to the nominal LHC, and for operation at a levelled luminosity of 5 10³⁴ cm^-2.s^-1, which is five times higher than the nominal LHC peak luminosity. Crab Cavities (CCs) are planned to compensate the geometric luminosity loss created by the increased crossing angle by rotating the bunch, allowing quasi head-on collisions at the Interaction Points (IP). The CCs work by creating transverse kicks, and their failure may have short time constants comparable to the reaction time of the Machine Protection System (MPS), producing significant coherent betatron oscillations and fast emittance growth. Simulations of CC failure modes have been carried out with the tracking code SIXTRACK, using the newly added functionality called DYNK, which allows to dynamically change the attributes of the CCs. We describe these simulations and discuss early, preliminary results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF095
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THPF125	MARS Tracking Simulations for the Mu2e Slow Extracted Proton Beam	extraction, scattering, septum, simulation	4010
	V.P. Nagaslaev, I.L. Rakhno Fermilab, Batavia, Illinois, USA
	Particle tracking taking into account interactions with fields and materials is necessary for proper evaluation of the resonant extraction losses and geometry optimization for the extraction beam line. This paper describes the tracking simulations for the Mu2e Resonant Extraction and discusses the geometry choices made based on these simulations.
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THPF150	3D Electromagnetic and Beam Dynamics Modeling of the LANSCE Drift-Tube Linac	DTL, simulation, linac, rfq	4079
	S.S. Kurennoy, Y.K. Batygin LANL, Los Alamos, New Mexico, USA
	The LANSCE drift-tube linac (DTL) accelerates the proton or H⁻ beam to 100 MeV. It consists of four tanks containing tens of drift tubes and post-couplers; for example, tank 2 is almost 20 m long and has 66 cells. We have developed 3D models of full tanks [1] in the DTL with CST Studio to accurately calculate the tank modes, their sensitivity to post-coupler positions and tilts, tuner effects, and RF-coupler influence. Electromagnetic analysis of the DTL tank models is performed using MicroWave Studio (MWS). The full-tank analysis allows tuning the field profile of the operating mode and adjusting the frequencies of the neighboring modes within a realistic CST model. Beam dynamics is modeled with Particle Studio for bunch trains with realistic initial beam distributions using the MWS-calculated and tuned RF fields and quadrupole magnetic fields to determine the output beam parameters and locations of particle losses. * S.S. Kurennoy, LINAC14, Geneva, Switzerland, 2014, MOPP106.
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Paper

Title

Other Keywords

Page

MOPJE032

A Steering Study for the ESS Normal Conducting Linac

DTL, linac, quadrupole, lattice

351

R. Miyamoto
ESS, Lund, Sweden

Construction of the European Spallation Source is rapidly progressing in Lund, Sweden, and preparations for commissioning of its proton linac has been underway for some time now. Accurate adjustment of accelerator components to achieve ideal beam parameters is the key to maximizing performance and safe operation for any machine. This paper presents a study of beam steering for the normal conducting part of the proton linac of ESS.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE032

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MOPMA014

Design of Superconducting CW linac for PIP-II

linac, cryomodule, optics, operation

565

A. Saini, V.A. Lebedev, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Proton Improvement Plan (PIP) -II is a proposed roadmap to upgrade existing proton accelerator complex at Fermilab. It is primarily based on construction of superconducting (SC) linear accelerator (linac) that would be capable to operate in continuous wave (CW) mode. This paper will present reference design of SC linac and discuss motivations and requirements resulting in this layout and beam optics.

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MOPTY034

Distributed Beam Loss Monitor Based on the Cherenkov Effect in Optical Fiber

electron, radiation, positron, storage-ring

1004

Yu. Maltseva, F.A. Emanov, A.V. Petrenko, V.G. Prisekin
BINP SB RAS, Novosibirsk, Russia
F.A. Emanov
NSU, Novosibirsk, Russia
A.V. Petrenko
CERN, Geneva, Switzerland

A distributed beam loss monitor based on the Cherenkov effect in optical fiber has been implemented for the VEPP5 electron and positron linacs and the 510 MeV damping ring at the Budker INP. The monitor operation is based on detection of the Cherenkov radiation generated in optical fiber by means of relativistic particles created in electromagnetic shower after highly relativistic beam particles (electrons or positrons) hit the vacuum pipe. The main advantage of the distributed monitor compared to local ones is that a long optical fiber section can be used instead of a large number of local beam loss monitors. In our experiments the Cherenkov light was detected by photomultiplier tube (PMT). Timing of PMT signal gives the location of the beam loss. In the experiment with 20 m long optical fiber we achieved 3 m spatial resolution. To improve spatial resolution optimization and selection process of optical fiber and PMT are needed and according to our theoretical estimations 0.5 m spatial resolution can be achieved. We also suggest similar techniques for detection of electron (or positron) losses due to Touschek effect in storage rings.

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MOPTY055

Beam Loss Monitoring for Run 2 of the LHC

monitoring, injection, detector, database

1057

M.K. Kalliokoski, B. Auchmann, B. Dehning, F.S. Domingues Sousa, E. Effinger, J. Emery, V. Grishin, E.B. Holzer, S. Jackson, B. Kolad, E. Nebot Del Busto, O. Picha, C. Roderick, M. Sapinski, M. Sobieszek, C. Zamantzas
CERN, Geneva, Switzerland

The Beam Loss Monitoring (BLM) system of the LHC consists of over 3600 ionization chambers. The main task of the system is to prevent the superconducting magnets from quenching and protect the machine components from damage, as a result of critical beam losses. The BLM system therefore requests a beam abort when the measured dose in the chambers exceeds a threshold value. During Long Shutdown 1 (LS1) a series of modifications were made to the system. Based on the experience from Run 1 and from improved simulation models, all the threshold settings were revised, and modified where required. This was done to improve the machine safety at 7 TeV, and to reduce beam abort requests when neither a magnet quench or damage to machine components is expected. In addition to the updates of the threshold values, about 800 monitors were relocated. This improves the response to unforeseen beam losses in the millisecond time scale due to micron size dust particles present in the vacuum chamber. This contribution will discuss all the changes made to the BLM system, with the reasoning behind them.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPTY055

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MOPTY057

Feasibility Study of Monitoring the Population of the CERN-LHC Abort Gap with Diamond Based Particle Detectors

detector, monitoring, kicker, simulation

1065

O. Stein, F. Burkart, B. Dehning, R. Schmidt, C.B. Sørensen, D. Wollmann
CERN, Geneva, Switzerland

At the end of a physics fill and in case of a failure, the LHC beams must be extracted and transferred through a 750m long line to the beam dump block. During the rise of the extraction kickers to their full strength a particle-free abort gap, with a length of 3 us in the LHC filling pattern, is required to prevent beam losses that could lead to substantial quenching of magnets, with a risk of damage. Therefore the particle population in the abort gap, which is mainly due to un-bunched beam, is monitored. Above a certain threshold an active cleaning by excitation of betatron oscillations with the transverse feedback system is initiated. This paper describes a novel method of monitoring the abort gap population using diamond particle detectors for detecting the interactions of beam in the abort gap with neon gas, injected in the beam pipe. Two different layouts of the system and the expected interaction and detection rates are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPTY057

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MOPTY058

Response of Polycrystalline Diamond Particle Detectors Measured with a High Intensity Electron Beam

detector, electron, experiment, radiation

1069

O. Stein, F. Burkart, B. Dehning, R. Schmidt, C.B. Sørensen, D. Wollmann
CERN, Geneva, Switzerland
E. Griesmayer
CIVIDEC Instrumentation, Wien, Austria

Comprehensive understanding of beam losses in the LHC is required to ensure full machine protection and efficient operation. The existing BLM system using ionization chambers is not adequate to resolve losses with a time resolution below some 10 us. Ionization chambers are also not adequate to measure very large transient losses, e.g. beam impacting on collimators. Diamond particle detectors with bunch-by-bunch resolution have therefore been used in LHC to measure fast particle losses with a time resolution down to a level of single bunches. Diamond detectors have also successfully been used for material damage studies in other facilities, e.g. HiRadMat at the CERN-SPS. To fully understand their potential, such detectors were characterized with an electron beam at the BTF in LNF INFN Italy, with bunch intensities from 10³ to 10⁹ electrons. The detector response and efficiency has been measured with a 50 Ω and a 1 Ω read-out system. This paper describes the experimental setup and the results of the experiment. In particular, the responses of three samples of 100 um single-crystalline diamond detectors and two samples of 500 um polycrystalline diamond detectors are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPTY058

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MOPWI033

Advantages to an Online Multi-particle Beam Dynamics Model for High-power Proton Linacs

linac, operation, emittance, proton

1234

L. Rybarcyk, S.A. Baily, X. Pang
LANL, Los Alamos, New Mexico, USA

High-power proton linacs like the 800-MeV LANSCE accelerator typically use a physics-based approach and online single-particle and envelope beam dynamics models to establish nominal set points for operation. However, these models are not good enough to enable immediate transition to high-power operation. Instead, some amount of empirical adjustment is necessary to achieve stable, low beam-loss operation. At Los Alamos, we have been developing a new online model, which employs multiparticle beam dynamics, as a tool for providing more information and insight to the operations staff, especially during this transition to high-power operations. This presentation will discuss some of the advantages and benefits of using this type of tool in the tune-up and operation of a high-power proton linac.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI033

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TUBC1

Recent Progress and Operational Status of the Compact ERL at KEK

laser, operation, quadrupole, experiment

1359

S. Sakanaka, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondou, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sasaki, K. Satoh, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
KEK, Ibaraki, Japan
E. Cenni
Sokendai, Ibaraki, Japan
R. Hajima, S. Matsuba, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma
JAEA, Ibaraki-ken, Japan
J.G. Hwang
KNU, Deagu, Republic of Korea
M. Kuriki
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
Y. Seimiya
HU/AdSM, Higashi-Hiroshima, Japan

Funding: Work supported by the Photon and Quantum Basic Research Coordinated Development Program from the MEXT, and by the MEXT grant for promoting technology for nuclear security.
The Compact Energy Recovery Linac (cERL) is a superconducting test accelerator aimed at establishing technologies for the ERL-based future light source. After its construction during 2009 to 2013, the first CW beams of 20 MeV were successfully transported through the recirculation loop in February 2014*. Then, initial tuning of beams and evaluations of beam properties were carried out. From September to December in 2014, we are constructing a Laser Compton Scattering (LCS) source** which aims at demonstrating technology for the future high-flux quasi-monochromatic gamma-ray source. In the next run of the cERL, which begins at the end of January 2015, we plan such works as an increase in the beam current (from 10 uA to 100 uA), commissioning of the LCS source, and sustained tuning of beams for lower emittance. We will report up-to-date results of these developments.
* N. Nakamura et al., IPAC2014, MOPRO110; S. Sakanaka et al., LINAC14, TUPOL01.
** R. Nagai et al., IPAC2014, WEPRO003.

Slides TUBC1 [2.679 MB]

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TUPWA017

Collimation scheme for the ESRF Upgrade

lattice, radiation, collimation, shielding

1434

R. Versteegen, P. Berkvens, N. Carmignani, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, S.M. White
ESRF, Grenoble, France

The ultra low emittance foreseen for the ESRF Upgrade will translate into a limited Touschek lifetime, increasing substantially the loss rate around the ring compared to the present machine. Consequently it becomes crucial to know the distribution of electron beam losses to optimize the radiation shielding and to protect the insertion devices from radiation damage. Such loss maps of the storage ring can be produced thanks to the simulation of the Touschek scattering process along the lattice. It is shown that about 80 % of the beam losses can be collimated in a few chosen locations only, keeping the resulting lifetime reduction smaller than 10 %.

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TUPJE066

Development of an Abort Kicker at APS to Mitigate Beam Loss-induced Quenches of the Superconducting Undulator

kicker, injection, septum, simulation

1787

K.C. Harkay, J.C. Dooling, Y. Ivanyushenkov, R. Laird, F. Lenkszus, C.C. Putnam, V. Sajaev, J. Wang
ANL, Argonne, Ilinois, USA

Funding: Work supported by U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The first superconducting undulator (SCU0) at the Advanced Photon Source (APS) has been delivering 80-100 keV photons for user science since January 2013. SCU0 often quenches during beam dumps triggered by the machine protection system (MPS). SCU0 typically recovers quickly after a quench, but SCU1, a second, longer device to be installed in 2015, may take longer to recover. We tested using injection kickers as an abort system to dump the beam away from SCU0 and the planned location of SCU1. An alternate trigger was tested that fires the kickers with MPS. We demonstrated that controlling the beam dump location with kickers can significantly reduce the beam losses at SCU0, as measured by fiber optic (FO) beam loss monitors (BLMs), and can also prevent a quench. A dedicated abort kicker system has been developed based on elegant simulations. A spare injection kicker was modified to produce the required waveform. Injection kicker tests, simulations, and the abort kicker design are described. Demonstration of this strategy in APS has implications for the APS Upgrade, where more SCUs are planned.

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TUPTY045

Interactions between Macroparticles and High-Energy Proton Beams

proton, electron, simulation, vacuum

2112

S. Rowan, A. Apollonio, B. Auchmann, A. Lechner, O. Picha, W. Riegler, H. Schindler, R. Schmidt, F. Zimmermann
CERN, Geneva, Switzerland

A known threat to the availability of the LHC is the interaction of macroparticles (dust particles) with the LHC proton beam. At the foreseen beam energy of 6.5 TeV during Run 2, quench margins in the superconducting magnets will be 2-3 times lower, and beam losses due such interactions may result in magnet quenches. The study introduce an improved numerical model of such interactions, as well as Monte-Carlo simulations that give the probability that such events will result in a beam-dump during Run 2.

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TUPTY053

Roadmap towards High Accelerator Availability for the CERN HL-LHC Era

luminosity, radiation, operation, target

2143

A. Apollonio, M. Brugger, L. Rossi, R. Schmidt, B. Todd, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland

High Luminosity-LHC is the future upgrade of the LHC that aims at delivering an integrated luminosity of 3000 fb-1 over about 10 years of operation, starting from 2025. Significant modifications [1] will be implemented to accelerator systems, including new superconducting magnets, crab cavities, superconducting links, new collimators and absorbers based on advanced materials and design and additional cryo-plants. Due to the limit imposed by the number of simultaneous events at the experiments (pile-up) on peak luminosity, the latter will be levelled to 5*1034 cm^-2s⁻¹. The target integrated luminosity can only be achieved with a significant increase of the total available time for beam collisions compared to the 2012 LHC run, despite a beam current that is planned to double the nominal 0.58 A. Therefore one of the key figures of merit to take into account for system upgrades and new designs is their impact on the accelerator availability. In this paper the main factors affecting LHC availability will be discussed and predictions on the impact of future system upgrades on integrated luminosity presented. Requirements in terms of the maximum allowed number of dumps for the main contributing systems to LHC unavailability will be derived.

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THPF095

Limits on Failure Scenarios for Crab Cavities in the HL-LHC

simulation, luminosity, optics, collimation

3923

A. Santamaría García, H. Burkhardt, A. Macpherson, K.N. Sjobak, D. Wollmann, B. Yee-Rendón
CERN, Geneva, Switzerland
K. Hernandez-Chahin
DCI-UG, León, Mexico
B. Yee-Rendón
CINVESTAV, Mexico City, Mexico

The High Luminosity (HL) LHC upgrade aims for a tenfold increase in integrated luminosity compared to the nominal LHC, and for operation at a levelled luminosity of 5 10³⁴ cm^-2.s^-1, which is five times higher than the nominal LHC peak luminosity. Crab Cavities (CCs) are planned to compensate the geometric luminosity loss created by the increased crossing angle by rotating the bunch, allowing quasi head-on collisions at the Interaction Points (IP). The CCs work by creating transverse kicks, and their failure may have short time constants comparable to the reaction time of the Machine Protection System (MPS), producing significant coherent betatron oscillations and fast emittance growth. Simulations of CC failure modes have been carried out with the tracking code SIXTRACK, using the newly added functionality called DYNK, which allows to dynamically change the attributes of the CCs. We describe these simulations and discuss early, preliminary results.

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THPF125

MARS Tracking Simulations for the Mu2e Slow Extracted Proton Beam

extraction, scattering, septum, simulation

4010

V.P. Nagaslaev, I.L. Rakhno
Fermilab, Batavia, Illinois, USA

Particle tracking taking into account interactions with fields and materials is necessary for proper evaluation of the resonant extraction losses and geometry optimization for the extraction beam line. This paper describes the tracking simulations for the Mu2e Resonant Extraction and discusses the geometry choices made based on these simulations.

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THPF150

3D Electromagnetic and Beam Dynamics Modeling of the LANSCE Drift-Tube Linac

DTL, simulation, linac, rfq

4079

S.S. Kurennoy, Y.K. Batygin
LANL, Los Alamos, New Mexico, USA

The LANSCE drift-tube linac (DTL) accelerates the proton or H⁻ beam to 100 MeV. It consists of four tanks containing tens of drift tubes and post-couplers; for example, tank 2 is almost 20 m long and has 66 cells. We have developed 3D models of full tanks [1] in the DTL with CST Studio to accurately calculate the tank modes, their sensitivity to post-coupler positions and tilts, tuner effects, and RF-coupler influence. Electromagnetic analysis of the DTL tank models is performed using MicroWave Studio (MWS). The full-tank analysis allows tuning the field profile of the operating mode and adjusting the frequencies of the neighboring modes within a realistic CST model. Beam dynamics is modeled with Particle Studio for bunch trains with realistic initial beam distributions using the MWS-calculated and tuned RF fields and quadrupole magnetic fields to determine the output beam parameters and locations of particle losses.
* S.S. Kurennoy, LINAC14, Geneva, Switzerland, 2014, MOPP106.

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