CLARO: an ASIC for high rate single photon counting with multi-anode photomultipliers

• Published in: Journal of instrumentation 2017-08, Vol.12 (8), p.P08019-P08019
• Main Authors: Baszczyk, M., Carniti, P., Cassina, L., Ramusino, A. Cotta, Dorosz, P., Fiorini, M., Gotti, C., Kucewicz, W., Malaguti, R., Pessina, G.
• Format: Article
• Language: English
• Subjects: Anodes; Counting; Photomultiplier tubes; Photons; Power consumption; Redundancy; Soft errors; Transistors
• ISSN: 1748-0221; 1748-0221
• DOI: 10.1088/1748-0221/12/08/P08019

The CLARO is a radiation-hard 8-channel ASIC designed for single photon counting with multi-anode photomultiplier tubes. Each channel outputs a digital pulse when the input signal from the photomultiplier crosses a configurable threshold. The fast return to baseline, typically within 25 ns, and below 50 ns in all conditions, allows to count up to 107 hits/s on each channel, with a power consumption of about 1 mW per channel. The ASIC presented here is a much improved version of the first 4-channel prototype. The threshold can be precisely set in a wide range, between 30 ke− (5 fC) and 16 Me− (2.6 pC). The noise of the amplifier with a 10 pF input capacitance is 3.5 ke− (0.6 fC) RMS. All settings are stored in a 128-bit configuration and status register, protected against soft errors with triple modular redundancy. The paper describes the design of the ASIC at transistor-level, and demonstrates its performance on the test bench.