A robust large area x-ray imaging system based on 100 μ m thick Gas Electron Multiplier

Abstract

We have developed an imaging detector based on a non-standard GEM, made from a 100 μ m thick kapton foil (2-fold thicker than standard GEM's). The 100 micron thick GEM is produced using the same wet etching technique as the standard GEM and is less prone to the damage caused by discharges, creating a robust detector that can safely operate at high gain.In this work we present the results obtained with a cascaded gaseous electron multiplier composed by two 100 micron thick GEM and a 10× 10 cm2 bi-dimensional readout electrode with resistive charge division. We have recorded energy resolution of 21% and charge gains above 104 when the detector was irradiated with 5.9 keV X-rays emitted by a 55Fe radioactive source. We also present 10× 10 cm2 images acquired with the detector when irradiated with X-rays. The minimum position resolution recorded was 1.7 mm.