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| Uncertainty Evaluation of Calibration Factor for X-ray Dose Equivalent Instrument |
| LÜ Ya-zhu1,ZHAO Rui1,LI De-hong1,Shabiha·Tuerxun2,GUO Bin1 |
1. National Institute of Metrology, Beijing 100029,China
2. Xinjiang Uygur Autonomous Region Research Institute of Measurement and Testing, Urumqi, Xinjiang 830011, China |
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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.
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Received: 30 January 2020
Published: 28 August 2020
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2020, Vol. 41 
