IPAC2015 - List of Authors (Dehning, B.)

Paper	Title	Page
MOPTY055	Beam Loss Monitoring for Run 2 of the LHC	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	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	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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TUAC1	Beam Instrumentation and Diagnostics for High Luminosity LHC	1349
	O.R. Jones, E. Bravin, B. Dehning, T. Lefèvre, H. Schmickler CERN, Geneva, Switzerland
	The extensive array of beam instrumentation with which the LHC is equipped, has played a major role in its commissioning, rapid intensity ramp-up and safe and reliable operation. High Luminosity LHC (HL-LHC) brings with it a number of new challenges in terms of instrumentation that will be discussed in this contribution. The beam loss system will need significant upgrades in order to be able to cope with the demands of HL-LHC, with cryogenic beam loss monitors under investigation for deployment in the new inner triplet magnets to distinguish between primary beam losses and collision debris. Radiation tolerant integrated circuits are also being developed to allow the front-end electronics to sit much closer to the detector. Upgrades to other existing systems are also envisaged; including the beam position measurement system in the interaction regions and the addition of a halo measurement capability to synchrotron light diagnostics. Additionally, several new diagnostic systems are under investigation, such as very high bandwidth pick-ups and a streak camera installation, both able to perform intra-bunch measurements of transverse position on a turn by turn basis.
	Slides TUAC1 [4.490 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUAC1
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Paper

Title

Page

Beam Loss Monitoring for Run 2 of the LHC

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPTY057

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

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPTY058

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

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUAC1

Beam Instrumentation and Diagnostics for High Luminosity LHC

1349

O.R. Jones, E. Bravin, B. Dehning, T. Lefèvre, H. Schmickler
CERN, Geneva, Switzerland

The extensive array of beam instrumentation with which the LHC is equipped, has played a major role in its commissioning, rapid intensity ramp-up and safe and reliable operation. High Luminosity LHC (HL-LHC) brings with it a number of new challenges in terms of instrumentation that will be discussed in this contribution. The beam loss system will need significant upgrades in order to be able to cope with the demands of HL-LHC, with cryogenic beam loss monitors under investigation for deployment in the new inner triplet magnets to distinguish between primary beam losses and collision debris. Radiation tolerant integrated circuits are also being developed to allow the front-end electronics to sit much closer to the detector. Upgrades to other existing systems are also envisaged; including the beam position measurement system in the interaction regions and the addition of a halo measurement capability to synchrotron light diagnostics. Additionally, several new diagnostic systems are under investigation, such as very high bandwidth pick-ups and a streak camera installation, both able to perform intra-bunch measurements of transverse position on a turn by turn basis.

Slides TUAC1 [4.490 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUAC1

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)