The first test-beam results of MiniCACTUS-V2: an ASIC prototype with 60 ps time resolution and a fast recovery time

Abstract The MiniCACTUS_V1 (Cmos ACtive pixel Timing μ Sensor) is a Depleted Monolithic Active Pixel Sensor (DMAPS) prototype fabricated in LFoundry 150 nm CMOS technology that achieved a 65 ps time resolution and 60 ns recovery time with particle beams on a 0.5 mm × 1.0 mm pixel size. It aims at exploring the possibility of monolithic solution for timing in the ATLAS experiment. Encouraged by this promising result, a new prototype, MiniCACTUS_V2, was designed with two new pre-amplifiers (CSA2 and VPA) for a faster recovery time and a better time resolution. The pre-amplifier from MiniCACTUS_V1 (CSA) was also integrated and tested as a benchmark. In MiniCACTUS_V2, three different thickness (150 μ m, 175 μ m and 200 μ m) and three different pixel sizes (1.0 mm × 1.0 mm, 1.0 mm × 0.5 mm, 0.5 mm × 0.5 mm) are explored. This work presents the results from the first test beam of MiniCACTUS_V2, mainly on a 175 μ m thickness device. On the same pixel size and the same high voltage bias, the CSA2 achieved a similar time resolution (63 ps) compared with the CSA (60 ps) but a much faster recovery time (≤ 25 ns) without the optimization on the configurations. The total power consumption is 1.62 mW per channel with a 1.8 V power supply voltage in the analog front-end electronics for the new pre-amplifiers.