用于X射线成像的非晶硒合金膜的制备和性能测试

Preparation and Properties of Amorphous Selenium Alloy Film for X-Ray Imaging

在X射线诊断成像方面 ,非晶硒 (a Se)是最有前途的探测材料之一。通过实验研究了a Se合金膜的制备方法 ,用飞行时间方法测量了载流子的漂移迁移率和寿命 ,讨论了对a Se合金膜性能有重要影响的因素。通过对40 0 μm厚a Se合金膜X射线光电流的测量 ,确定了a Se合金膜对X射线的光电响应特性。实验表明 ,a Se合金膜具有线性的光电转换特性 ;灵敏度与场强有关。在 10V μm场强下 ,对于医疗诊断常用的轫致辐射X射线谱 ,用X射线在a Se合金膜中产生一电子 -空穴对约需 45eV的能量。

Amorphous selenium alloy (a-Se alloy) is currently of great interest as X-ray imaging receptor due to its high resolution. The a-Se alloy films are deposited by vacuum evaporation, the transport properties of hole and electron are measured by time of flight technique. Some factors, which affect the properties of a-Se alloy film, are discussed. X-ray photocurrent is measured by using 400 μm thick film. The results show that linear photoelectric conversion existed in a-Se alloy film, and its sensitivity to X-ray irradiation depends on electric field. The calculation indicates that about 45 eV is needed for X-ray to release an electric-hole pair in a-Se alloy film at 10 V/μm electric field.