Identification of Gamma Spectrum Decayed by 238Pu as a Low Energy Photon Source

Abstract

The gamma spectrum of 238Pu low energy photon source which was used for X-ray fluorescence analysis was analyzed by using P-type coaxial HPGe detector. There were characteristic rays of 233Pa, 224Ra, 212Pb, 212Bi and 208Tl in the spectrum except the characteristic gamma rays of 238Pu.233Pa was the decay product of 237Np, which was the raw material used to produce 238Pu. 224Ra, 212Pb, 212Bi and 208Tl were the daughter nuclei of 236Pu, which was by product in the process of 238Pu’s production. Gamma rays of 350, 440, 844, 1014, 1130, 1266, 1368, 1454 keV were caused by coulomb excitation that alpha particles bombarded encapsulation materials of the source, or nuclear excitation that gamma rays irradiated surroundings. After the basis of efficiency calibration, the radioactive activity of each radioactive nuclide was calculated by gamma ray spectrometry. The quality of each radioactive nuclide was calculated derived from the principle of radioactive equilibrium. Through the analysis of 238Pu’s gamma ray spectrum, the method to calculate the radioisotope activity and the purity of radioactive sources was offered.

Keywords

• 238pu low energy photon source characteristic ray gamma ray spectrometry efficiency calibration