Optical Readout Studies of the Thick-COBRA Gaseous Detector

TL;DR

This study investigates the optical readout of a Thick-COBRA gaseous detector, demonstrating its spatial resolution, gain characteristics, and potential for identifying structural issues through scintillation light analysis.

Contribution

It introduces an optical readout method for Thick-COBRA detectors and analyzes their gain, spatial resolution, and stability, advancing detector development.

Findings

Spatial localization better than hole pitch

Gain contributions from holes and anode strips visualized

Identified weak points and sources of instability

Abstract

The performance of a Thick-COBRA (THCOBRA) gaseous detector is studied using an optical readout technique. The operation principle of this device is described, highlighting its operation in a gas mixture of Ar/CF4 (80/20%) for visible scintillation light emission. The contributions to the total gain from the holes and the anode strips as a function of the applied bias voltage were visualized. The preservation of spatial information from the initial ionizations was demonstrated by analyzing the light emission from 5.9keV X-rays of an 55Fe source. The observed non-uniformity of the scintillation light from the holes supports the claim of a space localization accuracy better than the pitch of the holes. The acquired images were used to identify weak points and sources of instabilities in view of the development of new optimized structures.