CACTUS: A Depleted Monolithic Active Timing Sensor Using a CMOS Radiation Hard Technology

The planned luminosity increase at the Large Hadron Collider in the comingyears has triggered interest in the use of the particles' time of arrival asadditional information in specialized detectors to mitigate the impact ofpile-up. The required time resolution is of the order of tens of picoseconds,with a spatial granularity of the order of 1 mm. A time measurement at thisprecision level will also be of interest beyond the LHC and beyond high energyparticle physics. We present in this paper the first developments towards aradiation hard Depleted Monolithic Active Pixel Sensor (DMAPS), withhigh-resolution time measurement capability. The technology chosen is astandard high voltage CMOS process, in conjunction with a high resistivitydetector material, which has already proven to efficiently detect particles intracking applications after several hundred of Mrad of irradiation.