The microstrip vertex detector for the E687 experiment at Tevatron

A vertex detector has been realized to reconstruct with high efficiency the decay vertices of heavy flavours in the E687 photoproduction experiment at the FNAL Tevatron. The vertex detector consists of 12 microstrip planes with a strip-by-strip readout. The readout electronics consists of a low noise preamplifier, an amplifier and a fast integrating ADC. All these units were developed by the INFN Milano and taylored to the actual vertex detector in order to fully exploit its intrinsic capabilities. A test of a part of the microvertex detector has been carried out in the real experimental conditions at Fermilab during summer 1985. Detection efficiency, charge collection and charge sharing between adjacent strips, signal to noise ratio, spurious hits, cross-talk and correlations have been extensively investigated. A simulation program, which makes use of a purposely developed pattern recognition and of the measured performances of the microvertex, gives for the experiment a total sensitivity of ∝ 600 events/nb for beauty and ∝ 2x106 for charm in ∝ 2000 hours of data taking. (orig.)