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For the sake of determination of some physical factors for gibbsite – bearing marl, at the area under consideration, a cylindrical tube of length 60 cm and diameter 6 cm was used. This tube contains ten CR-39 detectors of area 1 cm*1 cm fixed on the inner side of the tube in mutual positions of fixed interval distance 5 cm for each. The measured radon gas concentrations ranged from 1027.87 ± 93.32 Bq/m3 to 1712.39 ± 126.19 Bq/m3, the exhalation rate ranged from 3.39E-5±3.08E-6 to 4.66E-5±3.00E-6 mBq/m2s−1. By using the measured value of porosity which is (49.19%), the measured diffusion coefficient was calculated, it ranged from 3.26 E-3 (m2 s−1) to 5.77E-8 (m2s−1) and the diffusion length ranged from 3.63 m to 56.19 m, these values were used to determine the depth of the top of radioactive layer, the obtained results was found to be 1.683 m.

Using solid state nuclear track detectors and employing CR-39 cylindrical technique, the depth of the subsurface uranium deposits were determined. This techniques depends mainly on the nuclear track detector situated in zigzag form inside a polyethylene cylinder of 65 cm length and 7 cm diameter. This technique was applied on a borehole in a granite mass Abu Rushied area, southeast area desert. The obtained results revealed that, the depth of U -ore deposited reached about 89 m with thickness nearly 24 m. The obtained data for radon concentrations were also used for the determination of the exhalation rates, the measured values for exhalation rate (mBqm−2h−1) varies between 6.14E-03 at h = 50 cm and 4.53E-02 at h = 10 cm, The obtained values are comparable with that recorded for the granite type of rock.