STAR Beam-Beam Counter (BBC) on East Magnet Poletip

The picture below shows the BBC scintillator annuli mounted on the east poletip of the STAR magnet for the FY2002 polarized proton run.  Twelve photomultiplier tubes (PMT) were enclosed in a light-tight box mounted to the 12 o'clock bracket used to attach the poletip to the STAR magnet.  PVC tubes, each containing twelve 0.9-mm diameter clear optical fibers, guide scintillation light from the tiles to the PMT's.


Last Update: 6 April 2002