A new method for evaluating uranium and thorium contents in different natural material samples by calculating the CR-39 and LR-115 type II SSNTD detection efficiencies for the emitted α-particles

Determination of Food Crops Contamination in Osun State, Nigeria Due to Radium-226, Thorium-232 and Potassium-40 Concentrations in the Environment

“…However, the values of annual intake of 232 Th in yam and maize were twice the reference of 1.5 Bq/kg in the diets (UNSCEAR, 2000). The consumption of these food crops can lead to enhanced dietary intakes of thorium series radionuclide (Okoji, et al, 2012) The committed effective dose to members of the public due to 238 U( 226 Ra) and 232 Th radionuclides from the consumption of food crops by members of the communities in Osun State is given by E u = I u x e(g) u (Misdaq et al, 2000) E Th = I Th x e(g) Th (Rzama, et al, 1994) Where I u (Bq) and I Th (Bq) are the annual intake of 238 U and 232 Th radionuclides respectively, e(g) u and e(g) Th are the ICRP ingestion dose coefficients for 238 U and 232 Th radionuclides respectively. (ICRP,1996).…”

Study of pollution in the El Jadida-Safi Atlantic coastal zone (Morocco) by using PIXE and SSNTD methods

“…For our experimental etching conditions, the residual thickness of the LR-115 type II detectors measured by means of a mechanical comparator is 5 mm. This thickness defines the lower (E min ¼ 1.6 MeV) and upper (E max ¼ 4.7 MeV) energy limits for registration of tracks of a-particles in LR-115 type II films (Misdaq et al, 2000). All a-particles emitted by the uranium and thorium series that reach the LR-115 detector at an angle lower than its critical angle of etching q 0 c with a residual energy between 1.6 MeV and 4.7 MeV are registered as bright track-holes.…”

“…By calculating first the detection efficiencies of the CR-39 (3 CR j and 3 0CR j ) and LR-115 type II (3 LR j and 3 0LR j ) SSNTDs for a-particles emitted by the thorium-232 and uranium-238 series inside a soil/water residue sample (Misdaq et al, 2000), and secondly by measuring track density rates (tracks cm À2 s À1 ) registered on the CR-39 ðr CR G Þ and LR-115 type II ðr LR G Þ films one can evaluate the 238 U and 232 Th contents inside the considered material sample.…”

238U and232Th concentrations in various foodstuffs in Morocco and resulting radiation doses to the members of the public

“…During the exposure period, α-particles emitted by the 238 U and 232 Th series bombarded the SSNTD films. After the exposure of one month, the films were etched in two NaOH solutions at optimal conditions of etching, ensuring good sensitivities of the SSNTD and a good reproducibility of the registered track density rates: the first solution of 2.5 mol l -1 normality at 60 °C for 120 minutes for LR-115 type II films and the second solution of 6.25 mol l -1 normality at 70 °C for 7 hours for the CR-39 detectors (Misdaq et al, 2000). After this chemical treatment, the track densities registered on the CR-39 and LR-115 type II detectors were measured by using an optical microscope.…”

“…By calculating the detection efficiencies of the CR-39 ( and ) and LR-115 II ( and ) SSNTDs for α-particles emitted by the uranium and thorium series inside a food material sample by using the "SSNTDDEαM" FORTRAN program (Misdaq et al, 2000), and then by measuring track density rates (tracks cm -2 s -1 ) registered on the CR-39 ( ) and LR-115 type II ( ), the 238 U C(U) and 232 Th C(Th) contents inside the considered material sample were determined by the relation (Misdaq et al, 2000): (1) and (2) where: S d and are the surface areas of the CR-39 and LR-115 type II films, respectively. R j and are the ranges in sample materials, of α-particles with an initial energy E j emitted by the nuclei of the uranium and thorium series, respectively.…”