IPAC2011 - List of Authors (Roderick, C.)

Paper

Title

Page

Handling of BLM Abort Thresholds in the LHC

2382

E. Nebot Del Busto, B. Dehning, E.B. Holzer, S. Jackson, G. Kruk, M. Nemcic, A. Nordt, A. Orecka, C. Roderick, M. Sapinski, A. Skaugen, C. Zamantzas
CERN, Geneva, Switzerland

The Beam Loss Monitoring system (BLM) for the LHC consists of about 3600 Ionization Chambers located around the ring. Its main purpose is to request a beam abort when the measured losses exceed a certain threshold. The BLM detectors integrate the measured signals in 12 different time intervals (running from 40 us to 83.8 s) enabling for a different set of abort thresholds depending on the duration of the beam loss. Furthermore, 32 energy levels running from 0 to 7 TeV account for the fact that the energy density of a particle shower increases with the energy of the primary particle, i.e. the beam energy. Thus, about 1.3·10⁶ thresholds must be handled and send to the appropriate processing modules for the system to function. These thresholds are highly critical for the safety of the machine and depend to a large part on human judgment, which cannot be replaced by automatic test procedures. The BLM team has defined well established procedures to compute, set and check new BLM thresholds, in order to avoid and/or find non-conformities due to manipulation. These procedures, as well as the tools developed to automate this process are described in detail in this document.

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
WEPC170	Handling of BLM Abort Thresholds in the LHC	2382
	E. Nebot Del Busto, B. Dehning, E.B. Holzer, S. Jackson, G. Kruk, M. Nemcic, A. Nordt, A. Orecka, C. Roderick, M. Sapinski, A. Skaugen, C. Zamantzas CERN, Geneva, Switzerland
	The Beam Loss Monitoring system (BLM) for the LHC consists of about 3600 Ionization Chambers located around the ring. Its main purpose is to request a beam abort when the measured losses exceed a certain threshold. The BLM detectors integrate the measured signals in 12 different time intervals (running from 40 us to 83.8 s) enabling for a different set of abort thresholds depending on the duration of the beam loss. Furthermore, 32 energy levels running from 0 to 7 TeV account for the fact that the energy density of a particle shower increases with the energy of the primary particle, i.e. the beam energy. Thus, about 1.3·10⁶ thresholds must be handled and send to the appropriate processing modules for the system to function. These thresholds are highly critical for the safety of the machine and depend to a large part on human judgment, which cannot be replaced by automatic test procedures. The BLM team has defined well established procedures to compute, set and check new BLM thresholds, in order to avoid and/or find non-conformities due to manipulation. These procedures, as well as the tools developed to automate this process are described in detail in this document.

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]