First tests of a reconfigurable depleted MAPS sensor for digital electromagnetic calorimetry

Abstract

Digital Electromagnetic CALorimetry relies on a highly granular detector where the cell size is sufficiently small so that only a single particle in a shower enters each cell within a single readout cycle. The DECAL sensor, a depleted monolithic active pixel sensor (DMAPS), has been proposed as a possible technology for future digital calorimeters. A DECAL sensor prototype has been designed and fabricated in the TowerJazz 180 nm CMOS imaging process, using a high resistivity 18 μm epitaxial Si layer. The prototype has a pixel matrix of 64 × 64 pixels with a pitch of 55 × 55 μm, and is read out using fast logic at 40 MHz. It can be configured to function as either a strip sensor, for particle tracking, or a pad sensor, counting the number of pixels above threshold for digital calorimetry. Preliminary results of chip characterisation, including digital summing logic, analogue pixel performance and threshold scans under laser illumination are presented.