The WELL detector

Abstract

We introduce the WELL detector, a new type of position-sensitive gas proportional counter produced using advanced Printed Circuit Board (PCB) technology. The WELL is based on a thin kapton foil, copper-clad on both sides. Charge amplifying micro-wells are etched into the first metal and kapton layers. These end on a micro-strip pattern which is defined on the second metal plane. The array of micro-strips is used for read-out to obtain 1-D positional information. First results from our systematic assessment of this device are reported. (C) 1999 Elsevier Science B.V. All rights reserved

High rate behavior and discharge limits in micro-pattern detectors

“…The expression provides the effective, or usable gain, contributing to the signal detection; in GEM structures, the real gain can be larger by an amount that depends on the applied fields, but does not exceed about 20% in normal operating conditions [37,38]. b) Full volume X-ray irradiation.…”

“…Recently introduced, the Micro-CAT [8], micro-groove [9] and WELL [10] detectors are in fact variants of the original CAT device [4], realized with the more sophisticated etching technologies developed for GEM. We have manufactured a WELL device replacing the open holes o n the back side of a standard GEM with collecting strips constituting anodes for the multiplying structure.…”

“…A nonexhaustive list of such innovative devices includes the micro-gap [2], micro-dot [3], "compteur à trous" (CAT) [4], small gap [5], micromegas [6], gas electron multiplier (GEM) [7], micro-CAT [8], micro-groove and WELL detectors [9,10]. For a recent review see for example [11,12].…”

Gas detectors: achievements and trends

“…Exploiting the kapton-etching technology developed for making GEM electrodes, other promising multiplying structures have been recently developed: the micro-groove [32], the WELL [33], the micro-wire detector [34]. All devices permit to reach gains above 10 4 .…”

Radiation imaging detectors made by wafer post-processing of CMOS chips

“…These devices show an excellent performance, but to ensure the success of a detector, a key issue is the possibility to mass produce the detectors in a semi-industrial process. Among other factors, GEM and Micromegas have outperformed many other promising Micro Patterned Gaseous Detectors like micro-gap [65], micro-dot [66], CAT [67], small gap [68], micro-CAT [69], micro-groove [70] and WELL [71], because their feasibility to be produced in enough quantities to supply the demand of several institutes and companies. A collaboration effort is currently ongoing between MESA+ University of Twente, Nikhef, SMC (Scottish Microelectronics Center, Edinburgh) and IZM Fraunhofer Institute in Berlin to post-process full size 200 mm Timepix wafers.…”