A fast low-noise line scan x-ray detector.
A fast, low-noise line scan detector (NIKOS) for digital radiography has been developed. It consists of an input x-ray phosphor screen that is coupled to a modified Reticon photodiode array by means of fiber optics with incorporated image intensifier. In its current version the detector can be operated with a maximum 500 Hz image acquisition rate for interlaced readout of two lines of 128 pixels each. Using a Gd2O2S:Tb x-ray input phosphor, an afterglow of 25% in the first subsequent readout was observed. We also conducted afterglow measurements on several other powder and single-crystal phosphors and the photodiode array. Using CdWO4, the afterglow of the detector is limited by the lag of the photodiode array of 4.5%. By modifying the readout electronics the noise of the photodiode array was reduced to below 1 Graylevel, corresponding to a signal-to-noise ratio of 5200. The detective quantum efficiency (DQE) of the detector ranged from 0.18 to 0.4 for typical signal levels. The sensitivity was 10% saturation per 1.9 mR entrance dose. The modular design of the NIKOS detector allows for individual selection of each component to optimize performance for a given application.
Glüer
C C
CC
II. Inst. f. Experimentalphysik, Universität Hamburg, West Germany.
Dix
W R
WR
Engelke
K
K
Graeff
W
W
Kupper
W
W
Stellmaschek
K H
KH
D004867:Equipment Design; D005336:Fiber Optic Technology; D008163:Luminescent Measurements; D055100:Optical Fibers; D011856:Radiographic Image Enhancement / Q000295:instrumentation*; D014963:X-Ray Intensifying Screens