CLARO-CMOS, A very low power ASIC for fast photon counting with Pixellated Photodetectors

Abstract

The CLARO-CMOS is an application specific integrated circuit (ASIC) designed for fast photon counting with pixellated photodetectors such as multi-anode photomultiplier tubes (Ma- PMT), micro-channel plates (MCP), and silicon photomultipliers (SiPM). The first prototype has four channels, each with a charge sensitive amplifier with settable gain and a discriminator with settable threshold, providing fast hit information for each channel independently. The design was realized in a long-established, stable and inexpensive 0.35 mm CMOS technology, and provides outstanding performance in terms of speed and power dissipation. The prototype consumes less than 1mW per channel at low rate, and less than 2mW at an event rate of 10MHz per channel. The recovery time after each pulse is less than 25 ns for input signals within a factor of 10 above threshold. Input referred RMS noise is about 7.7 ke (1.2 fC) with an input capacitance of 3.3 pF. With this value of input capacitance a timing resolution down to 10 ps RMS was measured for pulser signals of a few million electrons, corresponding to the single photon response for these detectors. ©2012 IOP Publishing Ltd and Sissa Medialab srl.