两台451P型电离室剂量仪时间常数的比较研究  

Comparative study on time constants of two 451P ionization chamber dosimeters

作　　者：刘科[1] 胡涵[1] 侯占仙 龚红月 许寒[1] 周宇航[1] LIU Ke;HU Han;HOU Zhanxian;GONG Hongyue;XU Han;ZHOU Yuhang(Zigong Center far Disease Control and Prevention,Zigong 643000 China)

机构地区：[1]自贡市疾病预防控制中心

出　　处：《中国辐射卫生》2019年第5期543-546,共4页Chinese Journal of Radiological Health

摘　　要：目的比较2台451P型电离室剂量仪的时间常数,探讨时间响应修正公式的应用。方法 X射线机采用两个剂量率水平进行曝光,较高剂量率水平采用不同的测量模式进行测量,记录仪器测量的周围剂量当量率,根据RC电路的时间响应修正公式进行数据拟合,求出仪器的时间常数τ。结果 2台451P型电离室剂量仪0~5μSv/h量程时间常数τ值分别为(3 476.4±124.9)ms和(3 676.4±144.4)ms,0~50μSv/h自动转换量程τ值分别为(2 051.6±249.5)ms和(2 047.0±271.9)ms,0~50μSv/h固定量程时间常数τ值分别为(1 123.8±85.9)ms和(1 242.0±91.8)ms。结论 2台451P型电离室剂量仪的时间常数无统计学差异,但与操作手册的给定值有统计学差异,应合理选择曝光时间和测量模式进行防护检测,并使用已检定的时间常数进行响应时间修正。Objective To compare the time constants of two 451 P ionization chamber dosimeters, and to discuss the application of the time response modified formula. Methods In the condition of two exposure level of X-ray machines, and different measurement modes were used to measure and record the ambient dose equivalent rate for the higher dose ratelevels. The time constants(τ) of the instrument were conducted by fitting the data using the time response of having a capacitance C and a resistance R in series. Results The fitting time constants(τ) of two 451 P ionization chamber dosimeters were(3 476.4±124.9) ms,(3 676.4±144.4) ms for the range of 0 μSv/h to 5 μSv/h,(2 051.6±249.5) ms,(2 047.0±271.9) ms for the automatic range of 0 μSv/h to 50 μSv/h, and(1 123.8±85.9) ms,(1 242.0±91.8) ms for the fixed range of 0 μSv/h to 50 μSv/h, respectively. Conclusion No significant statistical difference was found in the time constants of two 451 P ionization chamber dosimeters, but all of the fitting time constants were statistically significant different to the parameters in the operators manual. So the exposure time and measurement mode should be appropriately chosen for protection detection, and the results should be corrected by the time response correction formula with the certificated time constant.

关 键 词：时间常数 电离室剂量仪 周围剂量当量率 修正公式 

分 类 号：TL81[核科学技术—核技术及应用]