Further studies on the gain properties of a Gas Electron Multiplier with a Micro-Induction Gap Amplifying Structure (GEM-MIGAS) aimed at low-energy X-ray detection

A Gas Electron Multiplier with Micro-Induction Gap Amplifying Structure (GEM-MIGAS) is formed when the induction gap of the GEM is set between 50 and 100 μm using kapton pillars spaced at regular intervals. This configuration combines the properties of a GEM and Micromegas, allowing operation in tandem to generate high charge gains. We measured the essential operational parameters of this system using argon–isobutane (IB) and helium–IB gas mixtures. The present short induction gap GEM was able to achieve effective gains exceeding 2×104 using argon–IB and 105 using helium–IB mixtures. In view of the high gains achieved, particularly when using helium-based gas mixtures, these studies confirmed the possibility of using the present system for high-performance sub-keV X-ray detection.