IPAC2019 - List of Authors (Schmidt, R.)

Paper	Title	Page
MOPTS094	Dust Analysis from LHC Vacuum System to Identify the Source of Macro-Particle-Beam-Interactions	1082
SUSPFO100	use link to see paper's listing under its alternate paper code
	L.K. Grob, A. Apollonio, C. Charvet, E. Garcia-Tabares Valdivieso, H. Kos, R. Schmidt CERN, Geneva, Switzerland C. Neves Hochschule Furtwangen, Furtwangen, Germany
	Since in 2010 the first sub-millisecond beam losses were observed at varying locations all along the LHC, it is well known that dust can interact with high-intensity proton beams and cause significant beam losses. Initially the sudden localized losses were enigmatic and coined the phrase ’unidentified falling objects’ (UFOs), which is still widely used. These very fast beam losses have resulted in hundreds of premature beam dumps and even magnet quenches since the start of LHC. So far, the only mitigation strategy involved an optimization of dump thresholds and the beneficial conditioning effect which leads to a reduction of the UFO rate over time. To understand the physics involved in these events and to allow an active diminution, it is essential to know the chemical composition and the size of the dust particulates interacting with the protons. The exchange of a dipole magnet offered the unique opportunity to collect dust samples from inside the LHC vacuum system. They were extracted from the various components and analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy to reveal size distribution and abundant elements. The results of this investigation will optimize the existing UFO models and the improved understanding of the phenomenon may help to prevent future performance limitations. This is also of relevance for future projects, in particular for the Future Circular Collider (FCC) under study.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS094
About •	paper received ※ 15 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019
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THPRB031	Operational Performance of the Machine Protection Systems of the Large Hadron Collider During Run 2 and Lessons Learnt for the LIU/HL-LHC Era	3875
	M. Zerlauth, A. Antoine, W. Bartmann, C. Bracco, E. Carlier, Z. Charifoulline, R. Denz, B. Goddard, A. Lechner, N. Magnin, C. Martin, R. Mompo, S. Redaelli, I. Romera, B. Salvachua, R. Schmidt, J.A. Uythoven, A.P. Verweij, J. Wenninger, C. Wiesner, D. Wollmann, C. Zamantzas CERN, Geneva, Switzerland
	The Large Hadron Collider (LHC) has successfully completed its second operational run of four years length in December 2018. Operation will be stopped during two years for maintenance and upgrades. To allow for the successful completion of the diverse physics program at 6.5 TeV, the LHC has been routinely operating with stored beam energies close to 300 MJ per beam during high intensity proton runs as well as being frequently reconfigured to allow for special physic runs and important machine developments. No significant damage has incurred to the protected accelerator equipment throughout the run thanks to the excellent performance of the various machine protection systems, however a number of important observations and new failure scenarios have been identified, which were studied experimentally as well as through detailed simulations. In this contribution, we provide an overview of the performance of the machine protection systems throughout Run 2 as well as the important lessons learnt that will impact consolidation actions and the upgrade of the machine protection systems for the LIU/HL-LHC era.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB031
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPRB113	Concept of Beam-Related Machine Protection for the Future Circular Collider	4085
	Y.C. Nie, R. Schmidt, J.A. Uythoven, C. Wiesner, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland
	In the Future Circular Collider (FCC) study, a proton-proton circular collider (FCC-hh) is considered with a stored beam energy 20 times higher than that of the LHC. Any uncontrolled release of such energy could potentially result in severe damage to the accelerator components. Machine protection of the FCC-hh is hence very important and challenging. With a machine-protection strategy similar to the LHC, FCC would require up to three turns to dump the beam synchronously after a failure detection. Due to several possible ultrafast failures, which could lead to significant beam losses in a few turns, it is important to further reduce the reaction time of the machine protection system (MPS) for the FCC. Reducing the detection time of a failure by using faster beam monitors, e.g. diamond detectors, can reduce the time between a beam loss and the beam dump request. Communication delay of the interlock system to the beam dumping system can be reduced by using a more direct signal path. More than one beam-free abort gap will shorten the time required for the synchronization between the abort gap and the extraction kicker. Different failure scenarios are classified according to the speed of the failure onset and the subsequent increase of induced beam losses. The critical failure modes, their potential mitigations and impacts on the design of the MPS are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB113
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPTS066	Beam Impact Experiment of 440GeV/p Protons on Superconducting Wires and Tapes in a Cryogenic Environment	4264
	A. Will, A. Bernhard, A.-S. Müller KIT, Karlsruhe, Germany Y. Bastian, B. Bordini, M. Favre, B. Lindstrom, M. Mentink, A. Monteuuis, A. Oslandsbotn, R. Schmidt, A.P. Siemko, K. Stachon, M.P. Vaananen, A.P. Verweij, A. Will, D. Wollmann CERN, Geneva, Switzerland M. Bonura, C. Senatore UNIGE, Geneva, Switzerland A. Usoskin BRUKER HTS GmbH, Alzenau, Germany
	The superconducting magnets used in high energy particle accelerators such as CERN’s LHC can be impacted by the circulating beam in case of specific failure cases. This leads to interaction of the beam particles with the magnet components, like the superconducting coils, directly or via secondary particle showers. The interaction leads to energy deposition in the timescale of microseconds and induces large thermal gradients within the superconductors in the order of 100 K/mm. To investigate the effect on the superconductors, an experiment at CERN’s HiRadMat facility was designed and executed, exposing short samples of Nb-Ti and Nb₃Sn strands as well as YBCO tape in a cryogenic environment to microsecond 440 GeV/p proton beams. The irradiated samples were extracted and are being analyzed for their superconducting properties, such as the critical transport current. This paper describes the experimental setup as well as the first results of the visual inspection of the samples.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS066
About •	paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

MOPTS094

Dust Analysis from LHC Vacuum System to Identify the Source of Macro-Particle-Beam-Interactions

1082

SUSPFO100

use link to see paper's listing under its alternate paper code

L.K. Grob, A. Apollonio, C. Charvet, E. Garcia-Tabares Valdivieso, H. Kos, R. Schmidt
CERN, Geneva, Switzerland
C. Neves
Hochschule Furtwangen, Furtwangen, Germany

Since in 2010 the first sub-millisecond beam losses were observed at varying locations all along the LHC, it is well known that dust can interact with high-intensity proton beams and cause significant beam losses. Initially the sudden localized losses were enigmatic and coined the phrase ’unidentified falling objects’ (UFOs), which is still widely used. These very fast beam losses have resulted in hundreds of premature beam dumps and even magnet quenches since the start of LHC. So far, the only mitigation strategy involved an optimization of dump thresholds and the beneficial conditioning effect which leads to a reduction of the UFO rate over time. To understand the physics involved in these events and to allow an active diminution, it is essential to know the chemical composition and the size of the dust particulates interacting with the protons. The exchange of a dipole magnet offered the unique opportunity to collect dust samples from inside the LHC vacuum system. They were extracted from the various components and analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy to reveal size distribution and abundant elements. The results of this investigation will optimize the existing UFO models and the improved understanding of the phenomenon may help to prevent future performance limitations. This is also of relevance for future projects, in particular for the Future Circular Collider (FCC) under study.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS094

About •

paper received ※ 15 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

Export •

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

THPRB031

Operational Performance of the Machine Protection Systems of the Large Hadron Collider During Run 2 and Lessons Learnt for the LIU/HL-LHC Era

3875

M. Zerlauth, A. Antoine, W. Bartmann, C. Bracco, E. Carlier, Z. Charifoulline, R. Denz, B. Goddard, A. Lechner, N. Magnin, C. Martin, R. Mompo, S. Redaelli, I. Romera, B. Salvachua, R. Schmidt, J.A. Uythoven, A.P. Verweij, J. Wenninger, C. Wiesner, D. Wollmann, C. Zamantzas
CERN, Geneva, Switzerland

The Large Hadron Collider (LHC) has successfully completed its second operational run of four years length in December 2018. Operation will be stopped during two years for maintenance and upgrades. To allow for the successful completion of the diverse physics program at 6.5 TeV, the LHC has been routinely operating with stored beam energies close to 300 MJ per beam during high intensity proton runs as well as being frequently reconfigured to allow for special physic runs and important machine developments. No significant damage has incurred to the protected accelerator equipment throughout the run thanks to the excellent performance of the various machine protection systems, however a number of important observations and new failure scenarios have been identified, which were studied experimentally as well as through detailed simulations. In this contribution, we provide an overview of the performance of the machine protection systems throughout Run 2 as well as the important lessons learnt that will impact consolidation actions and the upgrade of the machine protection systems for the LIU/HL-LHC era.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB031

About •

paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

Export •

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

THPRB113

Concept of Beam-Related Machine Protection for the Future Circular Collider

4085

Y.C. Nie, R. Schmidt, J.A. Uythoven, C. Wiesner, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland

In the Future Circular Collider (FCC) study, a proton-proton circular collider (FCC-hh) is considered with a stored beam energy 20 times higher than that of the LHC. Any uncontrolled release of such energy could potentially result in severe damage to the accelerator components. Machine protection of the FCC-hh is hence very important and challenging. With a machine-protection strategy similar to the LHC, FCC would require up to three turns to dump the beam synchronously after a failure detection. Due to several possible ultrafast failures, which could lead to significant beam losses in a few turns, it is important to further reduce the reaction time of the machine protection system (MPS) for the FCC. Reducing the detection time of a failure by using faster beam monitors, e.g. diamond detectors, can reduce the time between a beam loss and the beam dump request. Communication delay of the interlock system to the beam dumping system can be reduced by using a more direct signal path. More than one beam-free abort gap will shorten the time required for the synchronization between the abort gap and the extraction kicker. Different failure scenarios are classified according to the speed of the failure onset and the subsequent increase of induced beam losses. The critical failure modes, their potential mitigations and impacts on the design of the MPS are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB113

About •

paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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

THPTS066

Beam Impact Experiment of 440GeV/p Protons on Superconducting Wires and Tapes in a Cryogenic Environment

4264

A. Will, A. Bernhard, A.-S. Müller
KIT, Karlsruhe, Germany
Y. Bastian, B. Bordini, M. Favre, B. Lindstrom, M. Mentink, A. Monteuuis, A. Oslandsbotn, R. Schmidt, A.P. Siemko, K. Stachon, M.P. Vaananen, A.P. Verweij, A. Will, D. Wollmann
CERN, Geneva, Switzerland
M. Bonura, C. Senatore
UNIGE, Geneva, Switzerland
A. Usoskin
BRUKER HTS GmbH, Alzenau, Germany

The superconducting magnets used in high energy particle accelerators such as CERN’s LHC can be impacted by the circulating beam in case of specific failure cases. This leads to interaction of the beam particles with the magnet components, like the superconducting coils, directly or via secondary particle showers. The interaction leads to energy deposition in the timescale of microseconds and induces large thermal gradients within the superconductors in the order of 100 K/mm. To investigate the effect on the superconductors, an experiment at CERN’s HiRadMat facility was designed and executed, exposing short samples of Nb-Ti and Nb₃Sn strands as well as YBCO tape in a cryogenic environment to microsecond 440 GeV/p proton beams. The irradiated samples were extracted and are being analyzed for their superconducting properties, such as the critical transport current. This paper describes the experimental setup as well as the first results of the visual inspection of the samples.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS066

About •

paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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