Timing in thick silicon detectors—An update

Abstract

Thick silicon detectors are becoming widely used with reliable detectors available. They are often considered as a part of coincidence setup, where the timing resolution is of a crucial importance. Since over-biasing of thick detectors is sometimes unpractical, the timing resolution can be compromised in thick detectors. For this article the electric and Ramo fields in a 1.4 by 1.4 mm 2 pad size and 1 mm thick pad detector were calculated. GEANT4 was used to determine the tracks of the interaction electron produced in photon interactions, and the drift of ionized carriers in the detector was simulated. The signals were processed using a virtual preamplifier, a CR-RC shaper with a shaping time of 200 ns and a leading edge discriminator. The distributions of delay of the trigger after the event were compared to the measurements and a good agreement was found, allowing for additional noise in experimental setup. We proposed and evaluated an alternative readout strategy reading signals from nine nearest pads which greatly reduces the effects of inhomogeneous Ramo field on the timing resolution.