Investigation of Copper-Less Gas Electron Multiplier Detectors Responses to Soft X-rays

Abstract

In this paper, we report on the systematic study of different variants of X-ray detectors based on Gas Electron Multiplier (GEM) technology using modified GEM foils with greatly reduced amount of copper. The main goal of this study was understanding the performance of such detectors applied in X-Ray Fluorescence (XRF) elemental analysis. Reduction of the amount of copper in the detector structure is crucial for suppression of XRF background from copper, but one has to ensure that key detector parameters are not affected by such modification. The tested detector variants include detectors with different types of copper-less GEM foils, which have been manufactured starting from standard copper-clad foils and removing partially the copper layer in additional post-processing steps. The results are analyzed and discussed with a particular focus on the energy resolution, uniformity of gas gain and energy resolution across the detector area, and on the long-term stability of the gas gain. Long-term stability tests performed for selected detectors do not indicate for any accelerated aging of the copper-less detectors compared to standard detectors using copper-clad GEM foils. The presented results lead us to conclude that the copper-less GEM detectors are promising devices to suppress the XRF background.

Application of Factorisation Methods to Analysis of Elemental Distribution Maps Acquired with a Full-Field XRF Imaging Spectrometer

“…Such a relatively simple modification results in a very significant reduction in the Cu fluorescence background, by a factor of 7 for the Ar/CO (70/30) gas mixture [ 31 ]. The results of detailed studies of such copperless detectors have been reported elsewhere [ 43 , 44 ].…”

The United States Department of Energy and National Institutes of Health Collaboration: Medical Care Advances via Discovery in Physical Sciences

“…Micropattern gas detectors (MPGDs) are charged particle-tracking detectors for particle physics research which provide ∼50 µm resolution while tolerating very intense beams such as in cancer therapy applications. 8 This technology is being explored for beam diagnostics as well as protoncomputed tomography. Finally, artificial intelligence (AI) techniques under exploration for particle physics detector design and optimization clearly can be leveraged for improving patient care via medical imaging and adaptive planning development.…”

“…Imaging approaches here target positron‐emitting radionuclides produced by hadron irradiation or using gamma cameras or Compton cameras designed to detect beam‐induced prompt gamma rays. Micropattern gas detectors (MPGDs) are charged particle‐tracking detectors for particle physics research which provide ∼50 μm resolution while tolerating very intense beams such as in cancer therapy applications 8 . This technology is being explored for beam diagnostics as well as proton‐computed tomography.…”

Energy sensitive and large area X-ray fluorescence imaging system based on GEM detectors

“…One of the approaches is to remove most of the copper conductive layer and to use only the chromium layer that is used to improve the adhesion between the kapton and the copper layer to bias the GEM foil [73]. Despite the clear contamination suppression reported [74], the process in which these GEM foils are produced is not clear and the chromium may also produce a contamination, with lower intensity, in the region of interest, at 5.41 keV [59].…”