Development of a technique for the calibration of HPGe detector to estimate radionuclides present in steel samples

摘要

The quantitative assay of radionuclides present in steel samples is required for the environmental safety as well as in the process control and quality control of the finished products. The standard sources should also be prepared in the required size and shape as that of the sample, for the efficiency calibration of the HPGe detector system. A method was developed and tested to use 152Eu point source for the determination of efficiency of an extended steel disk source using HPGe detector system. Standard point sources of 152Eu were prepared by transferring known amount of 152Eu activity by weight. Standard steel disk sources of required dimensions were also prepared by distributing uniformly the standard activity of 152Eu on both sides of the inactive steel disk. The extrapolated efficiency of the steel disk sample was determined using the efficiency of the 152Eu point source and it was compared with the efficiency determined using the standard sources of 152Eu prepared on the steel disks. The two efficiency calibration curves matched very well within the experimental limits. Using this efficiency calibration, a few steel samples were analyzed for the radionuclides present in them. The detections limits for most of the nuclides were much less than the specified limits. The method can further be extended for other types of geometries with suitable modifications for the changes in thickness and attenuation corrections.