The C9 Cerenkov Detector for E852

E852 is following a program envisaged in the original proposal which has first taken data with final states involving mesons from the non-strange sector and will progress with identification of charged Kaons starting in the 1997 run.

This stage of the experiment required the addition of a segmented Cerenkov counter, C9, to the experiment. This detector is placed downstream of the exit region of the MPS (a magnetic spectrometer) and upstream of the LGD (Lead Glass Detector).

The detector was used previously in experiments BNL E766 (1983-1986), FNAL E690 (1989-1992), and BNL E910, and has been upgraded for the 1997 run of BNL E852. It is a highly segmented gas threshold Cerenkov counter designed to present a minimum amount of material to traversing particles. The Cerenkov gas has a low threshold momentum (about 2.5 GeV/c) for charged pions.

The above drawing shows a perspective view of the detector, as seen from the rear (looking upstream). Cerenkov light is reflected off toroidal mirrors, illustrated in blue, to a set of secondary mirrors (not shown), which are right angle cones that focus the Cerenkov light to Photomultiplier tubes. Each secondary mirror "looks at" a single primary mirror.

Further technical information on the detector is available.

Back to Experiment Setup page.