Measurements of time resolution of the RD50-MPW2 DMAPS prototype using TCT and ⁹⁰Sr

Results in this paper present an in-depth study of time resolution for active pixels of the RD50-MPW2 prototype CMOS particle detector. Measurement techniques employed include Backside- and Edge-TCT configurations, in addition to electrons from a ⁹⁰Sr source. A sample irradiated to 5 · 10¹⁴ n_eq/cm² was used to study the effect of radiation damage. Timing performance was evaluated for the entire pixel matrix and with positional sensitivity within individual pixels as a function of the deposited charge. Time resolution obtained with TCT is seen to be uniform throughout the pixel's central region with approx. 220 ps at 12 ke^- of deposited charge, degrading at the edges and lower values of deposited charge. ⁹⁰Sr measurements show a slightly worse time resolution as a result of delayed events coming from the peripheral areas of the pixel.