1. National Institute of Metrology, Beijing 100029,China
2. Xinjiang Uygur Autonomous Region Research Institute of Measurement and Testing, Urumqi, Xinjiang 830011, China
Abstract：In order to accurately evaluate the uncertainty of calibration factors of protective instruments for X-ray dose monitoring, according to the relevant technical specifications, the reference value of dose equivalent rate at the reference point is measured by standard ionization chamber, and the display value of the instrument to be calibrated is obtained by using the substitute method, so as to determine the relevant influencing factors of the calibration factor results, and evaluate the uncertainty of the influencing factors respectively.The relative expanded uncertainty of instrument calibration factor is 5.0% (k=2). The main sources of influence on the uncertainty of calibration factors include the uniformity of radiation field for calibration, calibration factors and energy response of the standard ionization chamber itself, dose equivalent conversion factor, statistical standard deviation of display value of instruments to be tested, etc. In the process of calibration, the uncertainty of calibration factor can be improved by increasing the uncertainty level of standard reference value.
［1］International Atomic Energy Agency. Calibration of Radiation Protection Monitoring Instruments: Safety Series No.16［S］.2000.
［2］ISO 4037-1:1996 X and gamma reference radiation for calibrating dosimeters and dose-rate meters and for determining their response as a function of photon energy-Part 1: Radiation characteristics production methods［S］.
［3］GB/T 12162.1—2000 用于校准剂量仪和剂量率仪及确定其能量响应的X和γ参考辐射［S］.
［4］JJG 393—2018 便携式 X、γ辐射周围剂量当量(率)仪和监测仪 ［S］.
［5］Joint Committee for Guides in Metrology (BIPM, IEC, IFCC, ISO,IUPAC, IUPAP AND OIML). JCGM 100 Evaluation of Measurement Data-Guide to the Expression of Uncertainty in Measurement［S］. 2008.
［6］International Atomic Energy Agency. Measurement Uncertainty: A Practical Guide for Secondary Standards Dosimetry Laboratories: IAEA-TECDOC-1585［S］. 2008.
［7］JJG2043—2010 (60~250)kV X射线空气比释动能计量器具［S］.
［8］JJG2095—2012 (10~60)kV X射线空气比释动能计量器具［S］.
［9］JJF1059.1—2012 测量不确定度评定与表示［S］.
［10］Bouillon M, Roberts P A. Measurement of air kerma and ambient dose equivalent in a 137Cs beam［R］. Report BIPM-96/7, 1996.
［11］李德红,成建波,王培玮,等.γ射线空气比释动能测量不确定度分析［J］.计量学报, 2016,37(4):444-447.
Li D H,Cheng J B,Wang P W,et al.Uncertainty Analysis for Determination of Air Kerma in γ-ray Beam［J］.Acta Metrologica Sinica,2016,37(4):444-447.
［12］孙圣涛,吴金杰,张德亮,等.10~70kV低空气比释动能率X射线参考辐射质的建立与能谱的模拟［J］.计量学报, 2018,39(6A): 153-157.
Sun S T, Wu J J, Zhang D L, et al. Establishment of 10~70kV X-ray Low Air Kerma Energy Reference Radiation and Energy Spectrum Simulation［J］.Acta Metrologica Sinica,2018, 39(6A): 153-157.
［13］赵瑞,吴金杰,樊松,等. 环境水平X射线辐射质的建立及监测仪表校准方法研究［J］. 计量学报, 2018, 39(6A): 131-135.
Zhao R, Wu J J, Fan S, et al. Establishment of Environmental Level X-ray Radiation Qualities and Research of the Calibration Methods of Monitoring Instruments［J］.Acta Metrologica Sinica, 2018, 39(6A): 131-135.
［14］杜海燕,李凡,吴金杰, 等. 同步辐射单能X射线空气质量衰减系数的测量［J］. 计量学报, 2019, 40(2): 333-336.
Du H Y, Li F, Wu J J, et al.The Measurement of Synchrotron Radiation Single-energy X-ray Mass-attenuation Coefficient of Air［J］.Acta Metrologica Sinica, 2019, 40(2): 333-336.
［15］王志鹏,邢书明,王坤, 等.高能X射线下水等效材料对水的等效性研究［J］. 计量学报, 2020, 41(2): 257-262.
Wang Z P, Xing S M, Wang K, et al.Study on the Equivalence of Water Equivalent Materials to Water under High-energy X-ray［J］.Acta Metrologica Sinica, 2020, 41(2): 257-262.
2020, Vol. 41 
