Study on Automatic Measuring System of Dosimetric Parameters for Radiation Field

Abstract

X and γ ray reference radiation field is a necessary facility for the calibration of X and γ radiation dosimeter. The dosimetric parameters of radiation field directly affects the reliability of the transmission of numerical values. To measure the dosimetric parameters of the radiation field rapidly, a new automatic measuring system of dosimetric parameters for radiation field has been investigated, which enables remote control of the positioning of the manipulator and the measurement of the ionization chamber. It features preset measurement paths, automated measurements, readout and recording data, and the ability to derive measurement results. The dose-rate distribution, scattered radiation characteristics and uniformity of 137Cs γ-ray reference radiation field, 60Co γ-ray reference radiation field, low-energy, medium-energy and high-energy X-ray reference radiation field were measured by an automated measurement system. The results show that the air kerma rates at 1-6 m away from the 137Cs multi-source irradiation device and the 60Co single-source irradiation device are 0.67-25.61 mGy/h and 0.19-7.25 Gy/h, respectively. For the 137Cs multi-source irradiation device, the 60Co single-source irradiation device, the low energy X-ray machine and the medium and high energy X-ray machine, the scattered radiation are all less than 4%, and the radiation field diameter of radiation field at the distance of 1 m is 22 cm, 14 cm, 16 cm and 7 cm, respectively. The automated measurement system can achieve fast and accurate measurements of the radiation field, which can greatly reduce the workload of the operator and implement radiation protection optimization principles.

Keywords

• automatic measuring
• reference radiation field
• uniformity
• measurement efficiency
• accuracy