Characterization of GEM Digital Hadron Calorimeter with 13bit KPiX Readout System Using Particle Beams

The High Energy Physics Group at the University of Texas at Arlington has been developing a digital hadron calorimeter (DHCAL) for future linear colliders using double-layer Gas Electron Multiplier (GEM) detector in the sensitive gap. The group has built prototype double GEM detectors in several sizes and have exposed four 30cm x 30cm prototype GEM detectors to particle beams at Fermi National Accelerator Laboratory. One of these detectors utilized a 13bit KPiX chip and its accompanying read out system developed at the Stanford Linear Accelerator Center. This talk will present the results of the beam test data analysis to understand the characteristics and performance of the prototype detectors. More specifically, it will present the measured gain, response, and efficiency of the detectors as well as the dependence of these quantities on the ambient pressure, position at which the particle passes through the detector and the applied high voltage.