Time of flight measurements with the PH32 chip

Abstract

The front-end readout chip PH32, that is suitable for the measurement of {X-rays}, beta radiation and ions, is primarily dedicated to the dose rate measurement and basic spectroscopy. This article is focused on the Time-of-Flight (ToF) functionality used in particle tracking or ion mass spectroscopy. The PH32 chip was manufactured using a commercial 180 nm CMOS process and contains various possibilities for ToF measurements including Time-of-Arrival (ToA) counter in each individual measurement channel, a global ToA counter controlled by internal trigger logic and a trigger output with a proprietary differential signaling driver. Along with the energy measurement using the Time-over-Threshold (ToT) method, the time-walk effect of ToF may be corrected. The chip is optimized for the strip sensor capacitance of 8 pF with AC coupling and the electronic noise is established at 1100 e−. The measurements presented in this paper are focused on channel response to an injected charge including a measurement of the channel dispersion and the time-walk effect caused by the varying of the injected charge together with the results provided by the global ToA counter and the trigger output. A discussion of the ToF measurements made using a laser light source is presented for the individual channel counter and the global ToA counter including the time-walk effect correction.