Determination of uranium concentrations and ²³⁴U/²³⁸U activity ratio in some granitic rock samples by alpha spectrometry: application of a radiochemical procedure

The present study is an application of a radiochemical procedure using alpha spectrometry technique for determination of uranium isotopes ²³⁸U, ²³⁴U and ²³⁵U on 13 granitic samples. These samples were collected from Gabal Gattar area, Northeastern Desert, Egypt. The collected samples were digested using microwave technique with aqua regia and spiked with ²³²U for chemical yield and activity calculation. Separation of uranium isotopes from the samples was done by Dowex 1 x 4 (50-100 mesh) resin followed by source preparation using microprecipitation technique. The concentrations of ²³⁸U were ranged between 28.9±0.9 and 134.8±1.8 Bq/g, and the ²³⁴U concentrations were between 24±0.6 and 147.7±2.2 Bq/g. For the ²³⁵U, the activity concentrations were between 1.3±0.2 and 6.7±1.2 Bq/g. The activity ratio of ²³⁴U/²³⁸U was calculated and varied from 0.80 to 1.30. (author)