Use of the Peak-Detector mode for gain calibration of SiPM sensors with ASIC CITIROC read-out

Abstract

A: The Cherenkov Imaging Telescope Integrated Read Out Chip (CITIROC) is a 32-channel fully analogue front-end ASIC dedicated to the read-out of silicon photo-multiplier (SiPM) sensors that can be used in a variety of experiments with different applications: nuclear physics, medical imaging, astrophysics, etc. It has been adopted as front-end for the focal plane detectors of the ASTRI-Horn Cherenkov telescope [1, 2] and, in this context, it was modified implementing the peak detector reading mode to satisfy the instrument requirements.For each channel, two parallel AC coupled voltage preamplifiers, one for the high gain and one for the low gain, ensure the read-out of the charge from 160 fC to 320 pC (i.e. from 1 to 2000 photo-electrons with SiPM gain = 10 6 , with a photo-electron to noise ratio of 10). The signal in each of the two preamplifier chains is shaped and the maximum value is captured by activating the peak detector for an adjustable time interval.In this work, we illustrate the peak detector operation mode and, in particular, how this can be used to calibrate the SiPM gain without the need of external light sources. To demonstrate the validity of the method, we also present and discuss some laboratory measurements. K: Front-end electronics for detector read-out, Photon detectors for UV-visible and IR photons (solid-state)-Solid state detectors 1Corresponding author. 2Corresponding author. 3Corresponding author.

A Comprehensive Survey of Readout Strategies for SiPMs Used in Nuclear Imaging Systems

“…Figure 12a shows the use of a discriminator (comparator) to determine if an event occurred [161,162]. Delay units to enable proper comparison of the time stamps [163,164], time to amplitude converters (TAC) [165], and multi-channel analyzers [166,167] are required to accurately report the timing. Figure 12b filters the events within some range before the discriminator and improves the signal to noise [168].…”