Solid-State 1024 Pixel Linear X-Ray Detector

An X-ray sensitive detector of 1024 pixels for non-destructive testing is described. The detection pitch is 0.45 mm and the total sensitive length is 460 mm. In standard operation, the detector is in the path of an X-ray beam collimated with a 0.45 mm slit. The detector delivers a digital video signal as an object is displaced at constant speed through the X-ray beam. The image is displayed on a TV monitor using a frame memory. Each line is read in 7.8 ms. A 1024 x 512 pixels image is read in 4.4 s. The detector is an assembly of 16 arrays of 64 silicon photodiodes. A scintillating screen converts the X-ray flux into visible photons to which the silicon photodiodes are sensitive. The photodiode arrays are multiplexed by silicon Charge Transfer Devices. The functions of the detector are as follows : multiplexing of the 1024 pixels signals, analog to digital conversion and level compensations. The correction levels are stored in a digital memory. The main characteristics of the detector are as follows - energy detection range : 10 keV - 250 keV - nominal X-ray energy : 60 keV - noise equivalent X-ray dose : 5 X photons at 60 keV on the detector - saturation level : 300 p,11. at 60 keV - dynamic range : > 4000. Some applications of these detectors are given.