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

Mostajaboddavati, M.
Hassanzadeh, S.
Faghihian, H.
Abdi, M. R.
Kamali, M.

¹Department of Physics, University of Isfahan, Isfahan 81747-73441, Iran.
²Department of Chemistry, University of Isfahan, Isfahan 81747-73441, Iran. E-mail: [email protected]
³Central Laboratory, University of Isfahan, Isfahan 81747-73441, Iran

Journal of Radioanalytical & Nuclear Chemistry 268(3):p 539-544, June 2006.

A nonlinear function was applied in combination with the method of mixing activity calibration for fitting the experimental peak efficiency of HPGe spectrometers in the 50-2614 keV energy range. The preparation of Marinelli beaker standards of mixed gamma- and RG-Set at secular equilibrium with its daughter radionucliedes was studied. Self-absorption was measured for the activity calculation of the gamma-ray lines for daughters of ²³⁸U series, ²³²Th series, as well as ¹³⁷Cs and ⁴⁰K in soil samples. Self-absorption in the sample depends on a number of factors including sample composition, density, sample size and gamma-ray energy. Seven Marinelli beaker standards were prepared in different degrees of compaction with bulk density (ρ) of 1.000 to 1.600 g.cm⁻³. The detection efficiency versus density was obtained and the equation of selfabsorption correction factors was calculated for soil samples.