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Accession Number DE2012-1045804
Title Design for a Longitudinal Density Monitor for the LHC.
Publication Date 2012
Media Count 3p
Personal Author A. Boccardi A. Jeff A. Rabiller A. S. Fisher C. P. Welsch E. Bravin F. Roncarolo S. B. Pedersen T. Lefevre
Abstract Synchrotron radiation is currently used on the LHC for beam imaging and for monitoring the proton population in the 3 microsecond abort gap. In addition to these existing detectors, a study has been initiated to provide longitudinal density profiles of the LHC beams with a high dynamic range and a 50ps time resolution. This would allow for the precise measurement both of the bunch shape and the number of particles in the bunch tail or drifting into ghost bunches. A solution is proposed based on counting synchrotron light photons with two fast avalanche photo-diodes (APD) operated in Geiger mode. One is free-running but heavily attenuated and can be used to measure the core of the bunch. The other is much more sensitive, for measurement of the bunch tails, but must be gated off during the passage of the bunch to prevent the detector from being swamped. An algorithm is then applied to combine the two measurements and correct for the detector dead-time, afterpulsing and pile-up effects. Initial results from laboratory testing of this system are described here.
Keywords Accelerators
Dead time
Large hadron collider
Synchrotron radiation
Time resolution

Source Agency Technical Information Center Oak Ridge Tennessee
NTIS Subject Category 46 - Physics
Corporate Author European Organization for Nuclear Research, Geneva (Switzerland).
Document Type Technical report
Title Note N/A
NTIS Issue Number 1226
Contract Number DE-AC02-76SF00515

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