Spherical GEMs for parallax-free detectors

TL;DR

This paper introduces a novel method for creating spherical GEM detectors that eliminate parallax error, promising improved spatial resolution and rate capability for detecting x-rays, neutrons, or UV photons.

Contribution

It presents a new, cost-effective technique to produce spherical GEM foils and outlines plans for a fully spherical detector with superior performance.

Findings

Successful development of spherical GEM foils

Prototype plans for a spherical triple-GEM detector

Potential for improved resolution at wide angles

Abstract

We developed a method to make GEM foils with a spherical geometry. Tests of this procedure and with the resulting spherical \textsc{gem}s are presented. Together with a spherical drift electrode, a spherical conversion gap can be formed. This would eliminate the parallax error for detection of x-rays, neutrons or UV photons when a gaseous converter is used. This parallax error limits the spatial resolution at wide scattering angles. The method is inexpensive and flexible towards possible changes in the design. We show advanced plans to make a prototype of an entirely spherical triple-GEM detector, including a spherical readout structure. This detector will have a superior position resolution, also at wide angles, and a high rate capability. A completely spherical gaseous detector has never been made before.