Evaluation of the DECAL Fully Depleted monolithic sensor for outer tracking and digital calorimetry

The DECAL sensor is a depleted monolithic active pixel sensor (DMAPS) being developed to explore technological solutions for digital electromagnetic calorimeters. For this application, the number of pixels above threshold is used to estimate the shower energy and therefore the pixel size is required to be sufficiently small to avoid hit saturation. The DECAL and DECAL Fully Depleted (FD) sensors have been designed and fabricated in the TowerJazz 180 nm CMOS standard and modified imaging processes, respectively. The latter uses modifications to the implant configuration that improve charge collection and radiation hardness, including to the levels required for barrel ECAL regions of FCC-hh (few 1015 neq/cm2). Both DECAL variants feature a matrix of 64 × 64 pixels with a pitch of 55μm, read out every 25 ns. For DECAL FD, the logic has been modified to extend the in-pixel comparator threshold trim range from five to six bits, with the sixth bit used to de-activate the comparator. Characterisation results for the DECAL FD, including the pixel equalisation matrix, threshold scans testing under monochromatic X-rays and 90Sr source, are presented.