CERN Accelerating science

CMS Note
Report number CMS-CR-2012-239
Title The stability of vacuum phototriodes to varying light pulse loads and long term changes in response.
Author(s) Hobson, Peter (Brunel U.)
Collaboration for the CMS Collaboration
Imprint 20 Sep 2012. - 5 p.
In: PoS PhotoDet2012 (2012) pp.064
In: 3rd International Workshop on New Photon-detectors, LAL, Orsay, France, 13-15 Jun 2012, pp.064
Subject category Detectors and Experimental Techniques
Accelerator/Facility, Experiment CERN LHC ; CMS
Abstract Mesh anode Vacuum Phototriodes (VPTs) are radiation resistant, single gain-stage photomultipliers which are designed to operate in a strong quasi-axial magnetic field. These VPTs are used in the endcap electromagnetic calorimeter of the CMS experiment at the CERN LHC to detect scintillation light from lead tungstate crystals. Short term dynamic response changes occur because of pulse rate variations during normal LHC operation cycles. Over the longer term the effect of increasing integrated charge taken from the photocathode causes an overall degradation of response. We have investigated these effects over time periods exceeding two years of simulated operation and discuss the implications for the long term performance of the VPTs in CMS.
Copyright/License Publication: (License: CC-BY-NC-SA-3.0)

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 Record created 2012-10-15, last modified 2017-11-03


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