Miyajima Satoshi
Graduate School of Medicine, Course of Health Sciences, Osaka University, 1-7 Yamadaoka, Suita, Osaka, Japan, 565-0871.
Med Phys. 2003 May;30(5):771-7. doi: 10.1118/1.1566388.
A CdTe Schottky diode detector of 1 mm thickness was employed in diagnostic x-ray spectroscopy. The detector response to monoenergetic photons was investigated with gamma rays from the calibration sources (241Am and 133Ba). As spectral distortion due to carrier trapping, known as tailing, was small in gamma-ray spectra, the effects of carrier trapping were not taken into account in the calculation of response functions. The distortion due to the transmission of primary x rays and the escape of secondary x rays (K-fluorescent x rays and Compton-scattered x rays) from the crystal was included in the calculated response functions. X-ray spectra corrected using the response functions were in good agreement with the reference spectra obtained with a high-purity germanium detector. The results indicated that correction for the distortion due to carrier trapping is not necessary when using a thin CdTe detector in diagnostic x-ray spectroscopy.
在诊断X射线光谱学中使用了厚度为1毫米的碲化镉肖特基二极管探测器。利用校准源（241Am和133Ba）发出的伽马射线研究了探测器对单能光子的响应。由于载流子俘获导致的光谱畸变，即拖尾现象，在伽马射线光谱中较小，因此在响应函数的计算中未考虑载流子俘获的影响。在计算得到的响应函数中包括了由于初级X射线的透射以及二次X射线（K荧光X射线和康普顿散射X射线）从晶体中逸出所导致的畸变。使用响应函数校正后的X射线光谱与用高纯锗探测器获得的参考光谱吻合良好。结果表明，在诊断X射线光谱学中使用薄碲化镉探测器时，无需对载流子俘获导致的畸变进行校正。
