Electrical analysis of a planar-type digital X-ray detector with inert gas

Large-area digital X-ray image detectors are currently being investigated for medical diagnostic and non-destructive tests. In this paper, a new planar-type detector for diagnostic X-ray (using an inert gas) imaging is proposed, and its electrical characteristics are presented. Almost gas detectors are designed in the shape of a chamber, so we made a planar-type panel sample based on a plasma display panel (PDP) technique. The transparent electrodes and dielectric layer were formed on the front glass. Additionally, the bottom electrodes and dielectric layer were formed on the rear glass. Then, we injected an inert gas (xenon and helium) with various component ratios into the sample using by gas-filling equipment. We measured the dark current density and the X-ray sensitivity as functions of the electric field to investigate the electrical properties. From the results, a stabilized dark current density and a significant X-ray sensitivity were obtained. Also, the signal linearity was calculated, and a good linearity as a function of exposure dose could be realized over a wide diagnostic energy range. All linearity coefficient γ values were higher than 0.9. These results mean that the passive matrix-addressed flat panel gas detector can be used as a digital x-ray detector.