Development and test of a next-generation positron detector

This report is focused on the development and test of a TDC (time to digital converter) and amplifier circuit for a state-of-the-art positron detector with position sensitivity. A newly developed one chip amplifier-shaper-discriminator (ASD) circuit with 16 channels input and a high-resolution TDC with a timing resolution on the order of picoseconds were tested. Silicon photomultipliers (SiPMs) were employed to give electric pulses for the optical input coming from a pulsed laser. We have successfully controlled the threshold level of the ASD circuit and measured the time structure of the SiPMs, as well as their multiple photon response from the pulse height histogram and the time over the threshold (TOT) histogram measured by the sub-nano second TDC. This is a technical basis for the next generation detector system with the positron tracking capability.