A zero cross trigger with rise time correction for timing of Ge(Li)-detector pulses

Abstract

A method is proposed by which the timing signal from a Ge(Li)-detector may be improved by a factor of 8 compared with leading edge triggering. The detector pulse in the timing channel is limited and double delay-line clipped, so that the charge of the pulse between start and zero cross depends only on the slope of the pulse. This charge is integrated on a capacitor. At zero cross time, a constant current discharge of the capacitor is started, and a time correction is thus added to the zero cross signal, depending on the charge of the first part of the pulse corresponding to a rise time correction. The method is exact for pulses with linear slope and the maximal error is estimated for real Ge(Li) pulse form.