Test of accuracy of ISOCS efficiency calibration without a radioactive source in situ measuring

It is verified that the accuracy of ISOCS efficiency calibration without a radioactive source in situ measuring by the experiment is adequate. For saturated body source model, the efficiency deviation between ISOCS calibration and actual measured at low, medium and high energy are respectively less than 7%, 5% and 3%. For unsaturated wall, the nuclide activity deviation between ISOCS efficiency calculation and laboratory sampling measurement in low, medium and high energy are respectively less than 13%, 3% and 2.2%. The results show that ISOCS efficiency calibration method without a radioactive source is acceptable within a certain range deviation. (authors)