Impact of WO3-Nanoparticles on Silicone Rubber for Radiation Protection Efficiency.

Silicone rubbers are a good choice for shielding materials because of having elastic and attenuating properties as well as cost-effectiveness. Thus, the aim of this study was to prepare ground-breaking silicone rubber samples by adding WO3-nanoparticles and testing the performance of their radiation shielding ability against Cs-137, Co-60, and Am-241 gamma energy. Increasing the concentration of WO3 nanoparticles in silicone rubber (SR) led to decreasing the half-value layer (HVL) and mean free path (MFP) values determined for the samples tested. Furthermore, the values of MFP and HVL upsurged according to the enhancement of the photon energy. It is noteworthy that the prepared silicone rubber (SR) systems with 50 and 60 wt% concentrations of WO3-nanoparticles displayed lower HVL than the Bi2O3-containing silicone rubber (SR) systems. In the same way, studied silicone rubber SR-W60 represented the lowest HVL comprising iron ore containing silicone rubber.

Determination of 238U and 40K Radionuclide Concentrations in Some Granite Rocks by Gamma Spectroscopy and Energy Dispersive X-ray Analysis.

Uranium-238 (238U) and potassium-40 (40K) are important naturally occurring radionuclides. Gamma spectroscopy is a direct, non-destructive method used to determine radionuclide concentrations, but it suffers from the interference of gamma lines. 40K gamma spectroscopy is affected by background interference, which leads to a reduction in the minimum detectable activity. The energy dispersive X-ray analytical technique is quick, with fewer interference problems or background effects. However, it is an indirect method for calculating and deducing the concentrations of isotopes. The aim of the present study was to compare and evaluate both techniques so that they can be utilized efficiently. The results of 238U and 40K were measured by well-calibrated gamma spectroscopy and energy dispersive X-ray techniques. the results indicated that Halayeb White granite is the most environmentally safe compared to the other two types because it contains a very low concentration of uranium 238 and potassium 40.

Novel 3-D printed radiation shielding materials embedded with bulk and nanoparticles of bismuth.

In the present study, a new type of radiation shielding material was developed by using a 3-D printing technique which enables to create a light radiation shielding materials of a great variety of shapes and dimensions. Micro and nano bismuth particles were incorporated as a filler between the inner layers of polylactic acid thermoplastic polymer (PLA Plastic) designed of the investigated 3-D printed prototypes to achieve the desired radiation attenuation. The effect of particle size on the attenuation parameters were studied over the energy range from 0.0595 to 1.41 MeV. The mass and thickness needed to reduce the intensity of the incoming radiation to half of its original value were determined experimentally for pure polymer (ABS Plastic), polymer with bulk Bi, and polymer with nano Bi. The results reveal that bismuth NPs with average particle size of about 17 ± 3 nm have a greater mass attenuation capability than normal bulk bismuth particles, meaning they are more efficient and a lighter shield can be produced. The enhanced shielding ability of nano bismuth particles was contributed to the excellent particle distribution, leading to an increase in the probability of photons interacting with the bismuth atoms. The bismuth NPs 3-D printed objects can be considered as a promising radiation shielding candidates and also could be utilized in manufacturing of radiation medical phantom.

Investigation of Photon Radiation Attenuation Capability of Different Clay Materials.

This work aims to experimentally report the radiation attenuation factors for four different clays (red, ball, kaolin and bentonite clays) at four selected energies (emitted from Am-241, Cs-137, and Co-60). The highest relative difference in the mass attenuation coefficient (MAC) is equal to -3.02%, but most of the other results are much smaller than this value, proving that the experimental and theoretical data greatly agree with each other. From the MAC results, the shielding abilities of the clay samples at 0.060 MeV follow the order of: bentonite > red > ball > kaolin. Thus, at low energies, the bentonite clay sample provides the most effective attenuation capability out of the tested clays. The half value layer (HVL) increases as energy increases, which suggests that, only a thin clay sample is needed to sufficiently absorb the radiation at low energies, while at higher energies a thicker sample is needed to shield the same amount of high energy radiated. Furthermore, bentonite clay has the lowest HVL, while the kaolin clay has the greatest HVL at all energies. The radiation protection efficiency (RPE) values at 0.060 MeV are equal to 97.982%, 97.137%, 94.242%, and 93.583% for bentonite clay, red clay, ball clay, and kaolin clay, respectively. This reveals that at this energy, the four clay samples can absorb almost all of the incoming photons, but the bentonite clay has the greatest attenuation capability at this energy, while kaolin clay has the lowest.

7Be in soil, deposited dust and atmospheric air and its using to infer soil erosion along Alexandria region, Egypt.

This study investigated the radioactivity behavior of 7Be in surface soil, airborne and deposited dust along Alexandria region in Egypt. The results obtained were used to predict scavenging processes of 7Be from surface soil to infer soil erosion and land vulnerable to accelerated sea-level rise. The areal activity concentrations of 7Be in surface soil were investigated in 30 undisturbed sites and 7Be inventories were determined via deposited dust in 10 locations. Results of the former were found to be ranged from 78 Bq/m2 to 104 Bq/m2. High levels were observed in western sites associated with high dust deposition rate. On the other hand, low levels were found in the eastern sites, those may be attributed to scavenging processes such as land erosion toward the direction to the sea. The effective removal rates of 7Be were calculated using the box-model, showing a broad special trend of inventories generally decreasing eastwards. The scavenging rates were ranged between 3.13 yr-1 in western sites to 5.34 yr-1 in eastern ones which denote that the east of the city suffers from rapid soil erosion. The airborne 7Be was monthly monitored along the period from October 2014 to September 2015 through one site located at the mid of the city. The results revealed lower values in winter and autumn than in summer and spring ranged between 6.2 mBq/m3 and 10.5 mBq/m3. These levels are comparable with that in other world regions and the seasonal variations are associated with the prevailing climatic conditions in Alexandria region.