Timing System for Ge(Li)-Detectors

A timing system for coincidence and nuclear lifetime measurements with Ge(Li)-detectors is described. The timing discriminator, based on the ARC-principle, is designed using integrated circuits. Uncompensated pulses from low energy events near the threshold of the timing discriminator are eliminated by a special internal coincidence circuit. Output pulses caused by noise, are excluded by duration discrimination. The detector signals are amplified by a preamplifier and a fast amplifier with 2.5 and 3.5 nsec risetimes,respectively. The time resolution has been obtained 15.6 , 2.7 and 1.1 nsec FWHM for energies 50, 511 and 1330 keV, respectively, by using of a planar detector (1.9 cm3) with a charge collection time of 40 nsec. The differential peak shift in a range from 10 to 1330 keV was 1.2 nsec.