摘要
目的:PIN型硅光敏二极管探测器的结构特点,为我们利用其辐射输出特性来测量软X线提供了可能。本文的目的是,在已有的商用PIN型硅光敏二极管探测器中,研究选取一种适用于乳腺摄影自动曝光控制系统的探测器,并对其各种输出特性进行试验研究,从而可降低乳腺摄影自动曝光控制系统的生产成本。方法:首先,对7种不同类型的PIN型硅光敏二极管探测器进行编号,然后依次分别进行以下三方面的实验研究:输出线性,能量响应和数据稳定性;并进行相关统计学分析;然后,在这7种不同类型的PIN型硅光敏二极管探测器中,选取一种各种特性都相对理想的探测器,在FLATSE乳腺高频钼靶X光机上进行验证,并观察其是否满足乳腺摄影自动曝光控制系统的要求。结果:探测器输出对X射线强度(10mR～2R)完全线性(线性相关系数r>0.99);探测器输出对X射线能量响应变化小于±3%(光子能量40keV～150keV);探测器输出电流大于10-9A(40kV,50mA);在不同时间及湿度下所测得的各项数据均无统计学差异。结论:PIN硅光敏二极管探测器(沪5号)具有灵敏度高、探测效率高、能量分辨率好、可以在室温下使用,以及对湿度不敏感和体积小等优点,能满足乳腺摄影自动曝光控制系统的要求。所以,我们最后选择沪5号作为乳腺摄影自动曝光控制系统的探测器。
Objective： The structure features of the PIN photodiode provide us with a chance of measuring the soft X-ray according to its output characteristic. The purpose of this study is that we can study and choose the optimal detector for AEC in the commercial PIN photodiode detectors and make a research on its characteristic. Thus the cost price of AEC can be cut down. Method： Firstly, these 7 different kinds of PIN photodiode are labeled. Then we study the characteristic of 7 kinds of PIN photodiodes： the output linear, energy response and the constancy of detectors, and make data analysis and statistical processing. And then we need to choose tile optimal detector from these detectors. At last, we check whether it meets the requirements for the AEC in FLAT SE HIGH FREQUENCY MAMMOGRAPHIC UNIT. Result： The output is completely linear to X ray intensity （10mR-2R） （r〉0.99）. The output variation to X ray energy response is less than ±3%（photon energy 40 keV-150 keV）.The output current of the detector is more than 10^-9A（40 kV,50 mA）.There are no statistics differences between data measured in different times and humidity. Conclusion： PIN photodiode detectors （S5）have high sensitivity and detection efficiency, ideal energy resolution, be used in ordinary temperature, not sensitive to humidity, a small size and so on. The PIN photodiode detector S5 completely meets the above requirements and so it is used as the detector of AEC at last.
出处
《中国医学物理学杂志》
CSCD
2009年第1期975-977,1005,共4页
Chinese Journal of Medical Physics
