The purpose of this study is to determine the activity concentration levels of radionuclides of²²⁶Ra,²³²Th,⁴⁰K, and¹³⁷Cs in soil and wheat grain samples. A total of 72 samples of soil and wheat grains were collected in the study area. Measurements were performed using a gamma-ray spectroscopic system based on high purity germanium detector. The average activity concentrations of²²⁶Ra,²³²Th, and⁴⁰K in soil samples were found to be 14.7 ± 0.2 Bq/kg, 19.9 ± 0.5 Bq/kg, and 329 ± 5.4 Bq/kg, respectively, and for the measured wheat grain samples their values were found to be 0.4 ± 0.09 Bq/kg for²²⁶Ra, 0.36 ± 0.1 Bq/kg for²²⁸Ra, and 109.2 ± 2.2 Bq/kg for⁴⁰K. The calculated mean values of radium equivalent activity Ra_eq, outdoor absorbed dose rate D_out, and outdoor annual effective dose rate of the soil samples were found to be 68.55 Bq/kg, 32.5 nGy/h, and 0.039 mSv/year, respectively. Moreover, the radionuclide transfer factor from soil-to-wheat grains of naturally occurring radionuclides were found in this order⁴⁰K > ²²⁶Ra > ²²⁸Ra.

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An attempt has been made to prepare the nonlead-based gamma shielding materials by adding different weight percentages (0%, 10%, 20%, and 40%) of bismuth in high-density polyethylene (HDPE) matrix. Gamma shielding parameters such as linear attenuation coefficient (μ), mass attenuation coefficient (μ_m), half-value layer, tenth value layer relaxation length (λ), and percentage attenuation were determined for all synthesized samples using 3“×3” NaI (Tl) detector for 59.54 keV energy. The results obtained from attenuation studies have shown that the shielding efficiency of synthesized HDPE+Bi composites increases with an increase in the weight percentage of bismuth. The experimentally obtained mass attenuation coefficient values are compared with Monte Carlo simulation using Monte Carlo N-particle code and XCOM code and are in good agreement with each other. The mechanical parameters such as tensile strength, tensile modulus, and elongation at the break were also determined for synthesized composites. Among the prepared composites, HDPE containing 40 wt% of bismuth (HDPE+40% Bi) has shown good radiation shielding property for 59.54 keV gamma rays along with good mechanical properties. Therefore, HDPE+40% Bi can be considered as a better lead-free shielding material for low-energy gamma rays.

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We have studied the X-ray and gamma radiation shielding parameters such as mass attenuation coefficient, linear attenuation coefficient, mean free path, half-value layer, tenth-value layer, effective atomic numbers, electron density, exposure buildup factors, specific gamma-ray constant, and mechanical properties in some coordination polymers such as lead monoclinic-(I), lead monoclinic-(II), lead tetragonal, azelato barium (II) polymer, 1-D coordination barium polymer (I), helical lead (II) coordination polymer, calcium bromide polymer (I), calcium bromide polymer (II), 1D-cadmium coordination polymer, and 2D-cadmium coordination polymer. We have also studied the neutron shielding properties in the same coordination polymers. From the detailed study, it is clear that helical lead (II) coordination polymer is a good absorber for X-ray and gamma radiation. The attenuation parameters for neutron are higher for 1D coordination barium polymer (I) compared to that of other studied polymers. This work is useful in the field of radiation shielding.

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The aim of this study was to validate Acuros XB (AXB) algorithm for photon dose calculation on an indigenously fabricated low-density heterogeneous phantom. Phantom was fabricated using poly (methyl methacrylate) (PMMA) and racemosa wood. The measured Hounsfield units, relative electron density, and mass density were 726.5, 0.273, and 0.212 g/cc and 201.8, 1.201, and 1.175 g/cc for racemosa and PMMA, respectively. AXB results were compared against anisotropic analytical algorithm (AAA) and ion chamber (IC) measured data for 3 cm × 3 cm and 10 cm × 10 cm field size of 6 megavolts beam. AXB results were in better agreement with IC measured data at all measuring points in comparison to AAA. The discrepancies between AXB and IC measured data were 1.3%–2.2% for 3 cm × 3 cm, −1.5%–−0.9% for 10 cm × 10 cm at low-density region, and −3.6%–−1.6% for 3 cm × 3 cm, and −1.4%–−0.8% for 10 cm × 10 cm at secondary buildup region, whereas discrepancies between AAA and measured data were 1.6%–3.6% for 3 cm × 3 cm, −4.6%–−3.4% for 10 cm × 10 cm at low-density region, and within −5.3%–−2.1% for 3 cm × 3 cm and −1.5%–1.0% for 10 cm × 10 cm at the secondary build-up region. Therefore, AXB is more appropriate in dealing with low-density heterogeneity in comparison to AAA.

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A survey was conducted on the technical parameters (exposure factor) used on some X-ray examinations (skull posteroanterior javascript:window.print();, skull anteroposterior [AP], skull lateral [LAT], chest posteroanterior javascript:window.print();, chest lateral [LAT], abdomen anteroposterior [AP], and pelvis anteroposterior [AP]) in six hospitals across the three senatorial zones (Owerri, Orlu, and Okigwe) in Imo State, Nigeria. A total of 100 patients were included in the survey. For each patient, the technical parameters (mAs and kVp) were recorded during the specific medical examination. Patients' information such as age, mass, and height was also taken. The results showed that the kVp mean values obtained were 80.00, 75.00, 75.00, 73.58, 83.36, and 75.08 for skull PA, skull LAT, chest PA, chest LAT, abdomen AP, and pelvis AP examination, respectively, and the mAs mean values obtained were 26.30, 30.00, 31.29, 32.76, 41.46, and 29.00 for skull PA, skull LAT, chest PA, chest LAT, abdomen AP, and pelvis AP examinations, respectively. These values are lower than international standards which imply that the personnel at the X-rays diagnostic center visited are doing fine.

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A first of its kind threshold activation proportional counter is developed using copper for the measurement of pulsed 14 MeV neutrons. The detector is of 26 mm outer diameter and 200 mm overall length. Tests at D-T facility showed that the detector is capable of measuring high-energy neutrons. The high-energy neutron sensitivity of the detector is estimated as 7.6 × 10⁻⁵ counts/neutrons cm^-2/s, and pulsed neutron sensitivity is estimated as 3.3 × 10⁷ neutrons pulse⁻¹ count⁻¹. The low-energy response of the detector can be discriminated by curve fitting method to the decay counts. An identical dimension silver-lined proportional counter with 0.5 counts/neutrons cm^-2/s thermal neutron sensitivity is developed for comparison with the copper detector. The silver activation detectors are conventionally used for neutron yield measurement of D-T-pulsed source. Experiments confirmed that compared to silver detector which is sensitive to low-energy neutrons, the copper detector is able to measure high-energy neutrons directly by threshold reaction.

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The diffusion of tritiated water (HTO) vapor from the spent fuel storage bay to the spent fuel storage building (SFSB) may lead to internal exposure to occupational workers. In order to reduce this internal exposure, air curtains are provided over the spent fuel storage bay to effectively remove HTO diffusing from spent fuel storage bay to SFSB. The radiation doses to the occupational workers are controlled well below the permissible level by monitoring the air concentration of HTO in the SFSB area. In the present study, it is brought out that few additional monitoring of air concentration of HTO above the spent fuel storage bay can give useful information about the effectiveness of air curtains in the removal of HTO and the estimation of environmental releases of HTO. A three-dimensional advection-diffusion-based model is developed to demonstrate the effectiveness of air curtains in the removal of HTO and for the estimation of environmental releases of HTO, utilizing these additional measurements. The study showed that air curtains are an effective mechanism to reduce the air concentration of HTO in SFSB and remove almost 50% of HTO activity using only around 24% of the ventilation air supplied to the SFSB. The environmental release rate of HTO estimated in this study was in good agreement with the measured release rate. The methodology developed here can also be utilized to carry out parametric studies to see the impact of changes in the parameters related with air curtains in the removal of HTO, thus for better designing of air curtains.

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Radon concentrations in different sources of water samples collected from five different regions of Egypt by alpha track dosimetry using LR-115 detectors were determined. The values of radon concentration in water samples did not exceed the maximum level of contamination of 11 BqL⁻¹ reported by the US Environmental Protection Agency and the recommended level of 10 BqL⁻¹ by UNSCEAR 2000. The calculated values of annual effective dose for adults, children, and infants from radon ingested are less than the reference level of 100 μSvy⁻¹ as recommended by the International Atomic Energy Agency, 2002 and WHO, 2009. From these results, it is concluded that there is no radiological risk related to radon ingested from the water samples analyzed in the study area of five different regions of Egypt.

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