- Detector of internally-reflected Cherenkov light
The Detector of Internally Reflected Čerenkov light (DIRC) was first proposed by
Blair Ratcliff as a tool for particle ID at aB-Factory . As a particle traveling close to the speed of light passes through thequartz it emitsČerenkov radiation , provided that (where "n" is the index of refraction in the quartz and is proportional to the particle's velocity). This radiation is transmitted through internal reflections to a stand-off box which contains photomultipliers. Knowledge of the angle at which the radiation was produced, combined with the track angle and the particle's momentum (measured in adrift chamber ) may be used to calculate the particle's mass.The DIRC differs from earlier
RICH andCRID Cherenkov light detectors in that the quartz bars used as radiators also transmit the light. The design was first used by theBaBar Collaboration atSLAC .References
* [http://www.slac.stanford.edu/BFROOT/www/Detector/DIRC/PID.html BaBar DIRC homepage]
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