Two-compartment detector for radon and thoron gases in El-Missikat and El-Erediya uranium exploratory tunnels, Central Eastern Desert, Egypt. - .

Two-compartment detector containing CR-39 SSNTD was employed to measure the concentrations of the two isotopes of radon gas; radon (222Rn) emanating from the 238U series and thoron (220Rn) which emanates from the 232Th series. This detector was tested inside the uranium exploratory tunnels at El Missikat and El Erediya, central eastern Desert, Egypt. Several detectors were distributed to cover the locations at different concentrations of 238U and 232Th in the granitic rocks and different conditions of ventilation in the two tunnels. The activity concentration of 238U inside El Missikat tunnel ranged between 305 and 684 (Bq/kg) with an average of 506.8±135.2 (Bq/kg) while it varied in El Erediya tunnel from 293 to 549 (Bq/kg) with an average of 374.6±79.44 (Bq/kg). In El Missikat tunnel 232Th obtained an activity concentration in the studied granites ranging between 206 and 366 (Bq/kg) with an average of 247±49.75 (Bq/kg) and in El Erediya tunnel it varied from 159 to 265 (Bq/kg) with an average of 193.5±34.06 (Bq/kg). In El Missikat tunnel, the average activity concentration of radon gas was 13.9±5.5 (kBq/m3) at the studied non-venilated locations and 1.69±1.07 (kBq/m3) at the ventilated locations while in El Erediya tunnel the average radon concentration was 5.77±2.59 (kBq/m3) at the non-ventilated area and 1.19±0.4 (kBq/m3) at the ventilated area. Thoron gas concentration got an average value of 3.83±2.3 (kBq/m3) at the non-ventilated locations inside El Missikat tunnel and 247±49.75 (kBq/m3) at the ventilated locations while in El Erediya tunnel this gas got an average concentration of 0.61±0.26 (kBq/m3) over the non-ventilated area and 0.3±0.2 (kBq/m3) over the ventilated area. Indeed, the concentrations of radon and thoron gases obtained by the two-compartment detector responded well to the concentrations of 238U and 232Th in the studied granitic rocks and they differentiated precisely between the ventilated and non-ventilated locations. On another hand, the detector showed linear response of accepted correlation between uranium and thorium concentrations and the effective doses due to the inhalation of radon and thoron gases and their decay products inside the studied tunnels. This, along with the easy use, light weight and small dimensions qualify the proposed detector as an individual monitor of radon and thoron gases for the workers in uranium mines. - See more at:.