Effects of High-energy Protons On the E771 Silicon Microstrip Detector

A silicon strip detector (SSD) system for use in very high rate experiments has been operated in Experiment E771 (Cox, 1989) at the Fermi National Accelerator laboratory. The detector electronics were designed (Swoboda, 1990; Bowden, 1990; Zimmerman, 1989; Christian, 1991) to meet the specific needs of Fermilab experiment E771 using ASIC chip sets where commercial circuits were not suitable. The electronics for the SSD were designed to operate at rates up to 60 Mhz and were operated at interaction rates up to 10(7) interaction/sec (beam rates of 2 x 10(8) proton/sec). In addition to being very fast, the detector for the 1991 run was very compact with 10000 channels of active detector in a volume of 5cm x 5cm x 10cm. An expansion of the system to 16000 channels is planned for the next Fermilab fixed target run. The strip pitch ranged from 25 mum in the center of the detector near the target to 100 mum pitch at the most downstream, outer edges of the detector. The readout is a latch design with pipelined readout and appears to have single strip efficiencies of approximately 75% even in the presence of a high radiation dose (approximately 10(14) protons/CM 2) and high leakage currents(approximately 1 nA/strip). The detector and associated amplifier electronics has presently been operated at 17-degrees-C and is designed to operate as low as 8-degrees-C.