Summing coincidence in rare event gamma-ray measurements under an ultra-low background environment

Full-energy peak (FEP) efficiencies of a HPGe detector equipped with an ultra-low background shield system are calibrated with the Monte Carlo method and further examined using summing peaks in a numerical way. Radionuclides $^{241}$Am, $^{137}$Cs, $^{60}$Co, $^{133}$Ba and $^{152}$Eu are used to construct the simulation model with the toolkit GEANT4. True summing \mbox{coincidence} factors (TSCFs) of $^{60}$Co, $^{133}$Ba and $^{152}$Eu are calculated and result in an improvement up to about 20\% in the FEP efficiency curve. Counts of summing coincidence $\gamma$ peaks in the spectra of $^{60}$Co and $^{152}$Eu can be well reproduced using the corrected efficiency curve within an accuracy of 3\%.


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2017May
Affiliations: 1Tsinghua University, china, 2Tsinghua University, china, 3Chinese Academy of Sciences, China, 4Chinese Academy of Sciences, China, 5Tsinghua University, china, 6Tsinghua University, china, 7Chinese Academy of Sciences, China, 8Tsinghua University, china, 9Chinese Academy of Sciences, China, 10Tsinghua University, china, 11Tsinghua University, china, 12Tsinghua University, china, 13Tsinghua University, china, 14Chinese Academy of Sciences, China, 15Chinese Academy of Sciences, China, 16Tsinghua University, china, 17Chinese Academy of Sciences, China, 18Chinese Academy of Sciences, China, 19Chinese Academy of Sciences, China, 20Chinese Academy of Sciences, China, 21Tsinghua University, china

Using a high energy electron beam for the imaging of high density matter with both high spatial-temporal and areal density resolution under extreme states of temperature and pressure is one of the critical challenges in high energy density physics . When a charged particle beam passes through an opaque target, the beam will be scattered with a distribution that depends on the thickness of the material. By collecting the scattered beam either near or off axis, so-called bright field or dark field images can be obtained. Read More


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