CALIBRATION METHOD AND ABSOLUTE MEASUREMENTS OF AIR KERMA OF DIAGNOSTIC X-RAY REFERENCE QUALITIES USING A FREE-AIR IONISATION CHAMBER
Author:
Zhao Rui1ORCID,
Wu Jinjie1,
Wen Yuqin1,
Lv Yazhu1,
Guo Bin1,
Liao Zhenyu1
Affiliation:
1. Division of Ionizing Radiation Metrology, National Institute of Metrology, No. 18, Bei San Huan Dong Lu, Chaoyang Dist., Beijing 100029, China
Abstract
Abstract
Accurate dose measurement is very important for diagnosing X-ray equipment. These equipment should be traced directly or indirectly to primary standard with as little uncertainty as possible. A parallel-plate free-air chamber was designed to measure air kerma of diagnostic X-ray absolutely. Different thickness of aluminium filters were used to obtain different radiation qualities according with IEC 61267. Correction factors were obtained by experiments and simulation, especially the air attenuation factor measured with vacuum method. The relative standard uncertainty of air kerma rate measurement was 0.46% and calibration factor was 0.53%. A transfer ionisation chamber was calibrated with Radiation Qualities in Radiation beams (RQR) qualities in National Research Council of Canada and National Institute of Metrology (NIM), the differences of calibration factors are less than 0.68%.
Funder
Capacity Improvement Project of State Administration for Market Regulation
Publisher
Oxford University Press (OUP)
Subject
Public Health, Environmental and Occupational Health,Radiology Nuclear Medicine and imaging,General Medicine,Radiation,Radiological and Ultrasound Technology