Cosmic-ray interactions in charged-couple devices in the DMTPC 4-shooter detector

Abstract

The Dark Matter Time Projection Chamber (DMTPC) is a low pressure (CF 4) detector that measures the two-dimensional vector direction of nuclear recoils, and it aims to directly detect dark matter. This paper explores cosmic ray interactions with the four charge-coupled devices (CCDs) of the 4-shooter detector, the largest existing prototype detector in the DMTPC project, by looking at surface runs at MIT with detector voltages off. Through this, the depth of the depletion region of each CCD is found, which can be further used in understanding not only background rejection but also in understanding the relationship between measured CCD counts and energy deposited in the detector.