A simple method for rise-time discrimination of slow pulses from charge-sensitive preamplifiers

Performance of a simple method of particle identification via pulse rise-time discrimination is demonstrated for slow pulses from charge-sensitive preamplifiers with rise times ranging from 10 to 500 ns. The method is based on a comparison of the amplitudes of two pulses, derived from each raw preamplifier pulse with two amplifiers with largely differing shaping times, using a fast peak-sensing ADC. For the injected charges corresponding to energy deposits in silicon detectors of a few tens of MeV, a rise-time resolution of the order of 1 ns can be achieved. The identification method is applicable in particle experiments involving large-area silicon detectors, but is easily adaptable to other detectors with a response corresponding to significantly different pulse rise times for different particle species.