The time-projection ring imaging cherenkov (rich) counter - new experimental results

A TPC-type RICH-counter with a 200 × 200 mm 2 quartz window and a 1.27 mm wire pitch MWPC has been tested in a 10 GeV/c π - beam. The MWPC is equipped with optical screens (called "cloisons") between the anode wires, with the purpose of absorbing the secondary UV-photons emitted from the charge avalanches around the wires. The test results show that the cloisons effectively suppress the noise caused by the photon reemission, without affecting the detection efficiency for single photoelectrons in the MWPC.