非晶硒对X射线光电转换特性的研究

非晶硒X射线光电导具有很高的固有空间分辨率,有可能研制探测X射线成象的平板化数字器件,在探测X射线成象方面倍受注目.它对X射线的光电转换特性和灵敏度是重要的性能参数之一.我们制作了约400μm厚的非晶硒膜,在1～12.5V/μm场强范围,0.2～12mR/s照射率范围测量了X射线光电流值.实验结果显示,非晶硒具有线性的光电转换特性,其灵敏度随场强的增加而增加.计算表明,对于医疗诊断常用的轫致辐射X射线谱,用X射线在非晶硒中产生一电子-空穴对所需的能量W±约50eV(10V/μm场强)

PHOTOELECTRIDC CONVERSION PROPERTIES OF AMORPHOUS SELENIUM TO X-RAYS

Amorphous selenium (α-Se) is becoming most promising X-ray imaging receptor material due to its high inherent spatial resolution and the capable of solid state digital detector.The photoelectric conversion properties and sensitivity of α-Se to X-rays is important for such receptor.About 400μm α-Se layer has been deposited,with α-Se layer sandwiched between two electrodes,X-ray photocurrent is measured in exposure rate ranging from 0.2mR/s to 12mR/s,electric field (F) ranging from 1V/μm to 12.5V/μm.The results show that α-Se has linear photoelectric conversion properties,and its sensitivity depends on electric field (F).Our calculation indicates that W±,the energy needed to release an electron-hole pair,is about 50eV at 10V/μm electric field for X-ray commonly used in medical fluorscopy.