IPAC2011 - List of Authors (Effinger, E.)

Paper

Title

Page

Beam Loss Monitors Comparison at the CERN Proton Synchrotron

1341

S.S. Gilardoni, S. Aumon, E. Effinger, J. Gil Flores
CERN, Geneva, Switzerland
U. Wienands
SLAC, Menlo Park, California, USA

CERN is planning the renovation and upgrade of the beam loss detection system for the Proton Synchrotron (PS). Improved performance in speed–to be able to monitor beam loss on a bunch-by-bunch basis–and in long-term stability–to reduce or avoid the need for periodic calibration–are aimed for. To select the most suitable technology, different detectors were benchmarked in the machine with respect to the same beam loss. The characteristics of the different detectors, the results of the measurement campaign and their suitability as future monitors for the PS are presented.

TUPC136

Analysis of Fast Losses in the LHC with the BLM System

1344

E. Nebot Del Busto, T. Baer, B. Dehning, E. Effinger, J. Emery, E.B. Holzer, A. Marsili, A. Nordt, M. Sapinski, R. Schmidt, B. Velghe, J. Wenninger, C. Zamantzas, F. Zimmermann
CERN, Geneva, Switzerland
N. Fuster
Valencia University, Atomic Molecular and Nuclear Physics Department, Valencia, Spain
Z. Yang
EPFL, Lausanne, Switzerland

About 3600 Ionization Chambers are located around the LHC ring to detect beam losses that could damage the equipment or quench superconducting magnets. The BLMs integrate the losses in 12 different time intervals (from 40 us to 83.8 s) allowing for different abort thresholds depending on the duration of the loss and the beam energy. The signals are also recorded in a database at 1 Hz for offline analysis. During the 2010 run, a limiting factor in the machine availability were sudden losses appearing around the ring on the ms time scale and detected exclusively by the BLM system. It is believed that such losses originate from dust particles falling into the beam, or being attracted by its strong electromagnetic field. This document describes some of the properties of these "Unidentified Falling Objects" (UFOs) putting special emphasis on their dependence on beam parameters (energy, intensity, etc). The subsequent modification of the BLM beam abort thresholds for the 2011 run that were made to avoid unnecessary beam dumps caused by these UFO losses are also discussed.

WEPC172

Beam-induced Quench Test of a LHC Main Quadrupole

2388

A. Priebe, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, E.B. Holzer, C. Kurfuerst, E. Nebot Del Busto, A. Nordt, M. Sapinski, J. Steckert, A.P. Verweij, C. Zamantzas
CERN, Geneva, Switzerland
A. Priebe
EPFL, Lausanne, Switzerland

Unexpected beam loss might lead to transition of a superconducting accelerator magnet to a normal conducting state. The LHC beam loss monitoring (BLM) system is designed to abort the beam before the energy deposited in the magnet coils reaches a quench-provoking level. In order to verify the threshold settings generated by simulation, a series of beam-induced quench tests at various beam energies have been performed. The beam losses are generated by means of an orbit bump peaked in one of the main quadrupole magnets. The analysis not only includes BLM data but also data from the electrical quench protection and cryogenic systems. The measurements are compared to Geant4 simulations of energy deposition inside the coils and corresponding BLM signal outside the cryostat. The results are also extrapolated to higher beam energies.

THOAA03

Overview of LHC Beam Loss Measurements

2854

B. Dehning, A.E. Dabrowski, M. Dabrowski, E. Effinger, J. Emery, E. Fadakis, V. Grishin, E.B. Holzer, S. Jackson, G. Kruk, C. Kurfuerst, A. Marsili, M. Misiowiec, E. Nebot Del Busto, A. Nordt, A. Priebe, C. Roderick, M. Sapinski, C. Zamantzas
CERN, Geneva, Switzerland
E. Griesmayer
CIVIDEC Instrumentation, Wien, Austria

The LHC beam loss monitoring system based on ionization chambers is used for machine protection, quench prevention and accelerator optimization. After one full year of operation it can be stated that its main functionality, that of the protection of equipment, has proven to be very robust with no issues observed for hundreds of critical beam loss events and the number of false beam aborts well below expectation. In addition the injection, dump and collimation system make regular use of the published loss measurements for system analysis and optimisation, such as the determination of collimation efficiency in order to identify possible intensity limitations as early as possible. Intentional magnet quenches have been performed to verify both the calibration accuracy of the system and the accuracy of the loss pattern predictions from simulations. Tests have also been performed with fast loss detectors based on single- and polycrystalline CVD diamond, which are capable of providing nanosecond resolution time loss structure. This presentation will cover all of these aspects and give an outlook on future performance.

Slides THOAA03 [1.972 MB]

Paper	Title	Page
TUPC135	Beam Loss Monitors Comparison at the CERN Proton Synchrotron	1341
	S.S. Gilardoni, S. Aumon, E. Effinger, J. Gil Flores CERN, Geneva, Switzerland U. Wienands SLAC, Menlo Park, California, USA
	CERN is planning the renovation and upgrade of the beam loss detection system for the Proton Synchrotron (PS). Improved performance in speed–to be able to monitor beam loss on a bunch-by-bunch basis–and in long-term stability–to reduce or avoid the need for periodic calibration–are aimed for. To select the most suitable technology, different detectors were benchmarked in the machine with respect to the same beam loss. The characteristics of the different detectors, the results of the measurement campaign and their suitability as future monitors for the PS are presented.

TUPC136	Analysis of Fast Losses in the LHC with the BLM System	1344
	E. Nebot Del Busto, T. Baer, B. Dehning, E. Effinger, J. Emery, E.B. Holzer, A. Marsili, A. Nordt, M. Sapinski, R. Schmidt, B. Velghe, J. Wenninger, C. Zamantzas, F. Zimmermann CERN, Geneva, Switzerland N. Fuster Valencia University, Atomic Molecular and Nuclear Physics Department, Valencia, Spain Z. Yang EPFL, Lausanne, Switzerland
	About 3600 Ionization Chambers are located around the LHC ring to detect beam losses that could damage the equipment or quench superconducting magnets. The BLMs integrate the losses in 12 different time intervals (from 40 us to 83.8 s) allowing for different abort thresholds depending on the duration of the loss and the beam energy. The signals are also recorded in a database at 1 Hz for offline analysis. During the 2010 run, a limiting factor in the machine availability were sudden losses appearing around the ring on the ms time scale and detected exclusively by the BLM system. It is believed that such losses originate from dust particles falling into the beam, or being attracted by its strong electromagnetic field. This document describes some of the properties of these "Unidentified Falling Objects" (UFOs) putting special emphasis on their dependence on beam parameters (energy, intensity, etc). The subsequent modification of the BLM beam abort thresholds for the 2011 run that were made to avoid unnecessary beam dumps caused by these UFO losses are also discussed.

WEPC172	Beam-induced Quench Test of a LHC Main Quadrupole	2388
	A. Priebe, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, E.B. Holzer, C. Kurfuerst, E. Nebot Del Busto, A. Nordt, M. Sapinski, J. Steckert, A.P. Verweij, C. Zamantzas CERN, Geneva, Switzerland A. Priebe EPFL, Lausanne, Switzerland
	Unexpected beam loss might lead to transition of a superconducting accelerator magnet to a normal conducting state. The LHC beam loss monitoring (BLM) system is designed to abort the beam before the energy deposited in the magnet coils reaches a quench-provoking level. In order to verify the threshold settings generated by simulation, a series of beam-induced quench tests at various beam energies have been performed. The beam losses are generated by means of an orbit bump peaked in one of the main quadrupole magnets. The analysis not only includes BLM data but also data from the electrical quench protection and cryogenic systems. The measurements are compared to Geant4 simulations of energy deposition inside the coils and corresponding BLM signal outside the cryostat. The results are also extrapolated to higher beam energies.

THOAA03	Overview of LHC Beam Loss Measurements	2854
	B. Dehning, A.E. Dabrowski, M. Dabrowski, E. Effinger, J. Emery, E. Fadakis, V. Grishin, E.B. Holzer, S. Jackson, G. Kruk, C. Kurfuerst, A. Marsili, M. Misiowiec, E. Nebot Del Busto, A. Nordt, A. Priebe, C. Roderick, M. Sapinski, C. Zamantzas CERN, Geneva, Switzerland E. Griesmayer CIVIDEC Instrumentation, Wien, Austria
	The LHC beam loss monitoring system based on ionization chambers is used for machine protection, quench prevention and accelerator optimization. After one full year of operation it can be stated that its main functionality, that of the protection of equipment, has proven to be very robust with no issues observed for hundreds of critical beam loss events and the number of false beam aborts well below expectation. In addition the injection, dump and collimation system make regular use of the published loss measurements for system analysis and optimisation, such as the determination of collimation efficiency in order to identify possible intensity limitations as early as possible. Intentional magnet quenches have been performed to verify both the calibration accuracy of the system and the accuracy of the loss pattern predictions from simulations. Tests have also been performed with fast loss detectors based on single- and polycrystalline CVD diamond, which are capable of providing nanosecond resolution time loss structure. This presentation will cover all of these aspects and give an outlook on future performance.
	Slides THOAA03 [1.972 MB]