We report on the properties of thick GEM-like (THGEM) electron multipliers made of 0.4 mm thick double-sided Cu-clad G-10 plates, perforated with a dense hexagonal array of 0.3 mm diameter drilled holes. Photon detectors comprising THGEMs coupled to semi-transparent CsI photocathodes or reflective ones deposited on the THGEM surface were studied with Ar/CO2 (70:30), Ar/CH4 (95:5), CH4 and CF4. Gains of ~100000 or exceeding 1000000 were reached with single- or double-THGEM, respectively; the signals have 5-10 ns rise times. The electric field configurations at the THGEM electrodes result in an efficient extraction of photoelectrons and their focusing into the holes; this occurs already at rather low gains, below 100. These detectors, with single-photon sensitivity and with expected sub-millimeter localization, can operate at MHz/mm2 rates. We discuss their prospects for large-area UV-photon imaging for RICH.
@article{arxiv.physics/0502131,
title = {Thick GEM-like multipliers - a simple solution for large area UV-RICH detectors},
author = {R. Chechik and A. Breskin and C. Shalem},
journal= {arXiv preprint arXiv:physics/0502131},
year = {2011}
}