DocumentCode :
469642
Title :
Very high radiation detector for the LHC BLM system based on secondary electron emission
Author :
Kramer, Daniel ; Dehning, Bernd ; Holzer, Eva Barbara ; Ferioli, Gianfranco
Author_Institution :
CERN, Geneva
Volume :
3
fYear :
2007
fDate :
Oct. 26 2007-Nov. 3 2007
Firstpage :
2327
Lastpage :
2330
Abstract :
Beam loss monitoring (BLM) system plays a vital role in the active protection of the LHC accelerators elements. It should provide the number of particles lost from the primary hadron beam by measuring the radiation field induced by their interaction with matter surrounding the beam pipe. The LHC BLM system will use ionization chambers as standard detectors but in the areas where very high dose rates are expected, the secondary emission monitor (SEM) chambers will be employed because of their high linearity, low sensitivity and fast response. The SEM needs a high vacuum for proper operation and has to be functional for up to 20 years, therefore all the components were designed according to the UHV requirements and a getter pump was included. The SEM electrodes are made of Ti because of its secondary emission yield (SEY) stability. The sensitivity of the SEM was modeled in Geant4 via the Photo-Absorption Ionization module together with custom parameterization of the very low energy secondary electron production. The prototypes were calibrated by proton beams in CERN PS Booster dump line, SPS transfer line and in PSI Optis line. The results were compared to the simulations.
Keywords :
beam handling equipment; calibration; energy loss of particles; ionisation chambers; secondary electron emission; BLM system; CERN PS booster dump line; Geant4 simulation; LHC BLM system; LHC accelerators; PSI Optis line; SEM chambers; SEM electrodes; SPS transfer line; beam loss monitoring system; beam pipe; calibration; ionization chambers; photoabsorption ionization module; primary hadron beam; proton beams; secondary electron emission; secondary emission monitor chambers; secondary emission yield stability; very high radiation detector; very low energy secondary electron production; Electron emission; Ion accelerators; Large Hadron Collider; Loss measurement; Monitoring; Particle accelerators; Particle beam measurements; Particle beams; Protection; Radiation detectors; LHC; beam instrumentation; beam loss monitor; secondary emission;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Nuclear Science Symposium Conference Record, 2007. NSS '07. IEEE
Conference_Location :
Honolulu, HI
ISSN :
1095-7863
Print_ISBN :
978-1-4244-0922-8
Electronic_ISBN :
1095-7863
Type :
conf
DOI :
10.1109/NSSMIC.2007.4436611
Filename :
4436611
Link To Document :
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