Comparison on in situ and laboratory gamma-ray spectroscopy of terrestrial gamma radiation in Ibadan, Southwestern Nigeria

Abstract

In situ - ray spectroscopic method of measeruments, using the calibration factor by Zombori et al, and laboratory method for soil samples were carried out in Ibadan, SW Nigeria. The average specific activities of 40K, 238U and 232Th in the soil were 299.0 16.5 Bqkg-1, 40.0 5.8 Bqkg-1 and 95.0 7.8 Bqkg-1, respectively, by in situ measurements, while for the laboratory measurements, the specific activities were found to be 355.0 19.7 Bqkg-1 for 40K, 31.0 5.9 Bqkg-1 for 238U and 63.0 7.5 Bqkg-1 for 232Th. Statistical analysis using F- hypothesis test of microsoft excel 5.0 analysis toolpak gave F-values to be 0.32, 0.52 and 0.00, respectively, which indicated that the radionuclides were not site dependent. The comparison shows a correlation of 0.65, 0.59 and 0.63 respectively, for 40K, 238U and 232Th.

Key words : gamma - ray; calibration; soil; activity; radionuclide


(Global Journal of Pure and Applied Sciences: 2002 8(4): 507-512)