Results from the measurement of GEM-based detector parameters performed with X-rays

The gas electron multiplier (GEM) based detectors have been widely developed in past years and have been proposed for many different applications. In this paper we report on the measurement of the currents induced on all the electrodes of a single-GEM detector when it is illuminated with a high intensity flux of low energy (5.9 keV) photons, using different configurations of electric fields and GEM voltages. From the analysis of these measurements we developed a phenomenological and analytical model able to describe the currents induced on the electrodes as a function of electric fields and GEM voltages when the detector is exposed to a continuous ionizing radiation. This model is also able to provide information on the characteristic parameters of the detector.