Manufacturing of a 70 × 70 mm2 LTCC strip electrode readout for Gas Electron Multiplier detectors

Abstract

Introduced by Fabio Sauli in 1997, the Gas Electron Multiplier (GEM) technology is commonly used in many high energy physics experiments. It has proven unique value in many scientific domains and adaptability to new research tasks. Typically, the GEM detectors are made with polyimide films (GEM foils and readout plate), halogen-free FR4 epoxy resins (supporting and stretching structures), conductive copper layers, etc. Because of outgassing and ageing, those components release in time residues of dust, moisture, and vapors. The residues pollute the gas mixture and consequently degrade the detector's working parameters. To avoid such a problem, devices can be constantly flushed by pure gas from an external source. This solution is not optimal for autonomous space detectors because of volume and weight limitations. The paper describes the successive work to develop an autonomous GEM detector without a gas mixture circulation system. As a solution, the use of Low-Temperature Cofired Ceramics (LTCC) materials was proposed and validated. The dedicated LTCC readout plates were manufactured and tested, and results are presented.