中文摘要：

谱仪的探测效率表征了探测器接收和记录信息的能力.为了更精确的测量α放射性核素的活度,定准α能谱仪的探测效率是非常必要的.本文利用查圆面源对窗的几何因子表和基于蒙特卡罗思想的MatLab模拟这两种方法对α谱仪探测效率进行了理论计算,并用Matlab软件对这两者所得的数据进行了比较分析,结果表明在5.5%的相对误差范围内两者可以近似相等.通过241Am标准面源与氡子体标准源对α谱仪的探测效率进行了测量,发现用241Am标准面源测得的探测效率与理论计算的探测效率相差很大,用氡子体标准源测得的探测效率与理论值符合的很好.研究表明241Am标准面源的活度的均匀性与准确性以及尺寸定位的准确性是造成241Am标准面源探测效率实验值与理论计算值差异的主要原因.

英文摘要：

A detector＇s capability of receiving and recording intormatlon is cnaractenzea oy a spectrometer＇s detection efficiency. It＇s very necessary to calibrate an alpha spectrometer＇ s detection efficiency for more accurate measurement of activity of alpha radionuclides. This paper theoretically calculates the alpha spetrometer＇s detection efficiency by two methods, looking up the table of geometrical factor of round non-point source to window and Madab simulation based on Monte Carlo idea. Then, a comparative analysis of data between the two methods is made by Matlab software. Both methods are approximately equal in the al- lowed error range with 5.5 %. The detection efficiency of alpha spectrometer is measuredby an ~1 Am standard source and radon progeny standard source. Theory detection efficien- cy is in accord with the experimental results used the radon progeny standard source and is different from the experimental results used the 241 Am standard source. The results show that uniformity and accuracy of radioactivity for 241 Am standard surface source and the ac- curacy of location dimensions cause detection efficiency errors between the experimental results and theoretical value