THGEM: A fast growing MPGD technology

Abstract

— Thick-GEMs (THGEMs) are simple and robust gaseous multipliers, derived from the GEM design and proposed for large-scale applications. Classical THGEMs consist of Printed Circuit Boards (PCBs) with a regular pattern of holes obtained by drilling; they are manufactured by industry in large series and large size; their response for different geometrical parameters and operational conditions has been extensively studied. Different substrates (ceramic, glass, PTFE, etc.) and various production procedures have also been investigated with promising results. Different design options, like highly segmented electrodes, and different architectures, in particular those based on the Thick-WELL design are being actively studied. THGEMs are used as gaseous multipliers and as reflective photocathodes for VUV photons when coated with a CsI layer. THGEM-based Photon Detectors have been successfully implemented in 2016 on COMPASS RICH-1 for a total active area of 1.4 m. Applications of THGEM (also called LEM) technology in the field of cryogenic detectors, in particular for double-phase large volume Ar ones are proposed. The recently discovered phenomenon of bubble assisted electro-luminescence in liquid Xe opens the way to local dual phase cryogenic detector configurations when using THGEMs. The detection of X-rays and neutrons using THGEM-based devices is a very active field. Promising results have been obtained using THGEMs for imaging applications.