A Fast Summing Preamplifier for Time-of-Flight Chambers of the HARP Experiment (PS214, CERN)

A technique for developing a fast summing preamplifier for resistive plate counters of the HARP experiment (PS214, CERN) is presented. The classic analog adder has been redesigned to obtain a minimum intrinsic jitter of 26 ps. This jitter has been attained via a trade-off with a charge summation accuracy of ~5%. The summing preamplifier has eight inputs and is based on the principle of summing a 104 × 240-mm² readout area containing eight strips with dimensions of 104 × 29 mm². The preamplifier is located inside the chamber. Its conversion factor is 100 mV/pC at a charge collection time of approximately 1 ns. The spread of the systematic timing error at the inputs is less than 30 ps. The power consumption is 350 mW. There are 368 summing amplifiers in the time-of-flight system.