The verify of the terrestrial measuring method of the cosmic ray response and calibration coefficient for the radiometer

Abstract

BackgroundMeasurement of radiation environment γ dose rate is greatly influenced by the high energy charged particles of cosmic rays which varies in different inspection sites. Different types of radiometers are affected differently due to the different cosmic ray response and calibration coefficient.PurposeThis study aims to verify the feasibility of the terrestrial measuring method for cosmic ray response and calibration coefficient of radiometer.MethodsFirst of all, calculation of cosmic ray response and calibration coefficient of radiometer by radiation test field measurement was proposed, then, two types of radiometer 6150AD and RSS-131 were employed to measure radiation field at two different γ dose rate levels. Repeat measurements were performed using the same radiometers at short intervals (4 days) to investigate the repeatability of measurement fitting results. Finally, four types of radiometer, i.e., RSS-131, 6150AD, BH3103 and RED-100, 14 sets in total γ radiometers, were used in both radiation inspection field and one test site of WanLv lake (in Guangdong province) for comparison and verification.ResultsMeasured results at radiation test field show that best cosmic ray response transfer effect is achievable between the same type of radiometers in the low dose rate with maximum dose rate less than 500 nGy·h-1. Experimental results of 11 radiometers of four types show that cosmic ray response values obtained by the calculation method determined by experiments, are basically consistent with the actual measured values of the same radiometer in Wanlv lake, and the relative deviation between the calibration coefficient determined by this method and the effective calibration coefficient of the radiometer is within 10%.ConclusionsThe terrestrial measurement method can replace the actual measurement to determine the cosmic ray response and calibration coefficient of the radiometer.

Keywords

• radiation inspection field
• radiation measuring instrument
• cosmic rays
• calibration coefficient