Identification of antiprotons in space using a compact RICH counter

A compact RICH counter using a monocrystal of NaF as radiator has been developed and will be an important part of a balloon-borne spectrometer to measure the energy spectrum of antiprotons in cosmic rays. The RICH counter is capable of separating the rare antiprotons from a large background of negative pions and muons with good efficiency. The Cherenkov photons are detected in the photosensitive MWPC operating at atmospheric pressure and using pad readout. The signals are amplified and multiplexed by the VLSI chip AMPLEX to reduce the number of cables but still having low noise and fast readout. Experimental and simulation results are presented