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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 (a Se) is one of the most promising detection materials for X-ray diagnostic imaging. The preparation method of a-Se alloy films was studied experimentally. The drift mobility and lifetime of carriers were measured by time-of-flight method. Factors influencing the performance of a-Se alloy films were discussed. By measuring the X-ray photoelectrical current of 40 a μm thick a Se alloy film, the optoelectronic response of a Se alloy film to X-ray was determined. Experiments show that, a Se alloy film has a linear photoelectric conversion characteristics; sensitivity and field strength. At 10 V μm field intensity, a common electron-beam X-ray spectrum for medical diagnosis requires about 45 eV of energy for generating an electron-hole pair in a Se alloy film by X-ray.