The effect of direct x-ray on CMOS APS imager for industrial application

Abstract

In this paper, we presented the effect of direct Xray after scintillator on the CMOS APS imager using modulation transfer function (MTF), noise power spectrum (NFS), and detective quantum efficiency (DQE). 50 kVp of X-ray tube voltage at the SID of 300 mm were set with continuous mode micro-focus X-ray machine on the assumption for industrial application such as PCB inspection. Lanex screen coupled CMOS APS imager was irradiated for long-term. From the experimental results, MTF and also DQE were degraded exponentially because of reduction of dynamic range caused by dark current or dark signal increase. For a given scintillator and an exposure condition, the degradation of image performance can be expected in case that the CMOS APS be used as a basic sensor array.