Development of a scintillating G-GEM detector for a 6-MeV X-band Linac for medical applications

We recently developed glass gas electron multipliers(G-GEMs) with an entirely new process using photo-etchable glass. The photo-etchable glass used for the substrate is called PEG3 ( HoyaCorporation). Taking advantage of low outgassingmaterial, we have envisioned a medical application of G-GEMs. A two-dimensional position-sensitive dosimetrysystem based on a scintillating gas detectoris being developed for real-time dose distribution monitoring in X-ray radiation therapy. The dosimetrysystem consists of a chamber filled with an Ar/CF4 scintillating gas mixture, inside of which G-GEM structures are mounted. Photons produced by the excited Ar/CF4 gas molecules during the gas multiplication in the GEM holes are detected by a mirror-lens-CCD-camera system. We found that the intensity distribution of the measured light spot is proportional to the 2D dose distribution. In this work, we report on the first results from a scintillating G-GEM detector for a position-sensitive X-ray beam dosimeter.