Utilization of a thin columnar cesium iodide (CsI) layer in gas avalanche microdetector

A thin (200-300 mu m) layer of columnar cesium iodide (CsI) crystals has been coupled to a conventional microstrip gas chamber. This layer provides the dominant source of electron production by incident charged particles in gas avalanche microdetectors, and is expected to make a significant improvement in spatial and time resolution, and detection efficiency, with respect to particle's angle of incidence. The CsI layer also makes the chamber useful for X- or gamma-ray detection with good position accuracy. In this paper, measurements are presented of signal enhancement due to the columnar CsI layer, and the efficiency versus angle. (C) 1999 Elsevier Science B.V. All rights reserved.