H_P(10)次级标准电离室几个重要性能测量及模拟计算

Measurement and simulation calculation for several important performances of H_P(10) secondary standard ionization chamber

介绍了T34035型H_p(10)次级标准电离室的结构和技术特性,实验测量了H_p(10)次级标准电离室的校准系数N_H和修正因子k(R,α),并评定给出校准系数N_H的相对扩展不确定度为4.6%(k=2),修正因子k(R,α)的相对扩展不确定度为6.0%(k=2)。在辐射质入射角≤75°时,12～1 250 keV范围内能量响应好于±20%;个人剂量当量率非线性在100μSv/h～3 Sv/h范围内好于±3%。采用MCNP5模拟计算了该电离室对部分窄谱N系列和低空气比释动能L系列的k(R,α)值,结果表明计算值与实验测量值之间的相对误差在±6%范围内。说明该电离室性能满足次级标准电离室要求,可以直接用于H_p(10)量值的传递。

The structure and technical characteristics of T34035 Hp ( 10) secondary standard ionization chamber are introduced. The calibration coefficient NH and correction factor k( R,α) of Hp ( 10) secondary standard ionization chamber are measured. The uncertainty of the calibration coefficient NH is 4. 6% ( k = 2) ,and the uncertainty of the correction factor k( R,α) is 6% ( k = 2) . When the radiation incident angle is less than 75 degrees,the energy response is better than ± 20% in the range of 12 keV - 1 250 keV,and the non-linearity of personal dose equivalent rate is better than ± 3% in the range of 100 μSv /h - 3 Sv /h. The k( R,α) values of some narrow spectrum N series and low air specific kinetic energy L series are simulated by MCNP5. The results show that the error between the calculated value and the measured value is within the range of ± 6%. The ionization chamber meets the requirements of the secondary standard ionization chamber and can be used directly for the transmission of Hp ( 10) value.