Applications of amorphous silicon image sensors for x-ray image capture in NDT

摘要

Amorhous silicon image sensors, developed by dpiX, A Xerox Company, offer an improved methodof acquiring digital x-ray images. Amorphous silicon image sensor technology provides the opportunity to have large format size similar to x-ray film, high resolution, wide dynamic range and in a compact package for ease of use in NDT applications. This paper will present a description of an amorphous silicon imaging system that incorporates an image sensor with an 8x10 inch x-ray image acquisition area. The image sensor has 1536 x 1920 127 micron pixels. Each pixel ocnsists of a photodiode for creating a charge in proportion to incoming ligh and a TFT to readout the charge. A low noise charge amplifier is used to provide a signal to a 12 bit ADC for obtaining a wide signal-to-noise ratio image with better dynamic range than can be achieved with film. A Gd sub 2 O sub 2 S: Tb phosphor screen is used to convert penetrating radiation into fluorescent light for detection by the amorphous silicon image sensor. Examples of NDT applications are presented showing the performance advantages of amorphous silicon image sensors.