The Thick-COBRA: a New Gaseous Electron Multiplier for Radiation Detectors

TL;DR

The paper introduces the Thick-COBRA, a novel gaseous electron multiplier with a patterned hole structure derived from existing designs, achieving high gains and good energy resolution for radiation detection.

Contribution

It presents the design, operation principle, and preliminary results of the Thick-COBRA, a new micro-hole electron multiplier with enhanced performance capabilities.

Findings

Achieved gains over 5×10^4 with X-ray sources.

Demonstrated 12.2% FWHM energy resolution in Ar-10%CH4.

Operated effectively with single photoelectrons.

Abstract

The operation principle and preliminary results of a novel gas-avalanche patterned hole electron multiplier, the Thick-COBRA (THCOBRA), are presented. This micro-hole structure is derived from the THGEM and MHSP. Sub-millimeter diameter holes are mechanically drilled in a thin G10 plate, Cu-clad on both faces; on one of the faces the Cu is etched to produce additional anode strips winding between circular cathode strips. Primary avalanches occurring within the holes are followed by additional ones at the anode-strips vicinity. Gains in excess of 5*104 were reached with 22.1 x-rays in Ar, Ne and Ar-10%CH4, with 12.2 % FWHM energy resolution in Ar-10%CH4. Higher gains were measured with single photoelectrons. This robust multiplier may have numerous potential applications.