Efficiency calibration and measurement of self-absorption correction of environmental gamma spectroscopy of soils samples using Marinelli beaker

摘要: A nonlinear function in combination with the method of mixing activity calibrated is applied for fitting the experimental peak efficiency of HPGe spectrometers in 59-2614 keV energy range. The preparation of Marinelli beaker standards of mixed gamma and RG-set at secular equilibrium with its daughter radionuclides was studied. Standards were prepared by mixing of known amounts of {sup 13B}a, {sup 241}Am,{sup 152}Eu,{sup 207}Bi,{sup 24}Na, Al{sub 2}O{sub 3} powder and soil. The validity of these standards was checked by comparison with certified standard reference material RG-set and IAEA-Soil-6 Self-absorption was measured for the activity calculation of the gamma-ray lines about series of {sup 238}U daughter,{sup 232}Th series,{sup 137}Cs and {sup 40}K in soil samples. Self-absorption in the sample will depend on a number of factor including sample composition, density, sample size and gamma-ray energy. Seven Marinelli beaker standards were prepared in different degrees of compaction with bulk density ( {rho}) of 1.000 to 1.600 g cm{sup -3} . The detection efficiency versus density was obtained and the equation of self-absorption correction factors calculated for soil samples.