http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
윤승만,한종철,Okla Joe,고종수,김영수,김호경 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.3
The development of a pixel-structured scintillator has recently been exploited to confine optical transport onto a corresponding photodiode pixel. This conceptual design of scintillators may provide high detection efficiency while preserving high spatial resolution in digital X-ray imaging detector systems. The sedimentation approach is one method to fill gadolinium-oxysulfide phosphors into a pixel-structured micro-well array. To fully understand the X-ray imaging characteristics of a pixel-structured design with sedimented gadolinium-oxysulfide phosphors, the imaging performance of gadolinium-oxysulfide phosphor layers made by using sedimentation should be characterized in advance. We have fabricated gadolinium-oxysulfide phosphor screens by using a simple sedimentation method. In order to characterize the imaging performances of the developed phosphor screens, we overlaid them onto a photodiode array with a pixel pitch of 48 microns and thus completed indirect-conversion X-ray imaging detectors. The imaging performance of the detector was investigated in terms of the modulation-transfer function (MTF), the noise-power spectrum, and the detective quantum efficiency (DQE). The results were compared with those of detectors employing commercial phosphor screens. Although the developed screen was about 1.5 times thicker than the commercial one, the X-ray sensitivity was comparable to that of the commercial phosphor. The MTF performance was worse than that of the commercial screen, and that MTF performance also governed the DQE performance of the detector over the entire spatial-frequency band. If the sedimented phosphors are pixel-structured with micro-well arrays, however, the MTF performance can be defined by using only the pixel size. Therefore, a design to enhance the X-ray sensitivity for the sedimentation method should be considered.