A simple software for swift computation of photon and charged particle interaction parameters: PAGEX

Fabrication of cadmium chloride PVA polymer composite for γ-ray shielding

Reducing the effect of exposure to radiation in places such as radiation labs, nuclear reactors, radiotherapy facilities, industries involving radiation, etc., is essential for the health of radiation workers. In such cases materials having flexibility added with high attenuation coefficient of radiation is required for manufacturing wearables. Even though materials such as lead compounds, building materials, etc., have high attenuation coefficient, they are toxic and rigid, making them unsuitable for this purpose. In this regard, blending compounds with polymers would lead to flexible materials with high shielding capability. In the present work, 25 wt% cadmium chloride in polyvinyl alcohol (PVA) polymer composite has been prepared using solution casting method. The obtained polymer composite is characterised by energy dispersive X-ray spectroscopy. The mass attenuation coefficients (μ/ρ) and half value layer (HVL) of gamma radiations were measured at various energies 511, 661, 1173 and 1332 keV using calibrated gamma ray spectrometer with NaI(Tl) detector and compared to WinXCom-calculated theoretical values. The measured μ/ρ and HVL are 0.089, 0.078, 0.064, 0.061 cm2/g and 0.685, 0.778, 0.985, 1.003 cm, respectively. It is found that the obtained experimental values are in good agreement with theoretical values within the experimental errors. Also, it is observed that the μ/ρ decreases and HVL increases with increase in energy. Even though PVA is not radiation resistant, when it is blended with 25 wt% cadmium chloride it shows good shielding property. Thus, the fabricated cadmium chloride-PVA polymer composite can be used for radiation shielding instead of toxic and expensive materials.

A Monte Carlo investigation of some important radiation parameters and tissue equivalency for photons below 1 keV in human tissues

The attenuation coefficients are important input values in estimating not only the dose and exposure in radiotherapy and medical imaging, but also in the proper design of photon shields. While studies are widely available above 1 keV, the attenuation coefficients of human tissues for photon energies less than 1 keV have not been studied yet. In this study, the attenuation coefficients of water and some human tissues were estimated for low energy photons using the MCNP6.1 code in the energy region 0.1 keV-1 keV. Mass attenuation coefficients were estimated at photon energies of 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950 and 1000 eV for water and ten human tissues (Soft, Breast, Lung, Bone, Brain, Eye lens, Ovary, Skin, Thyroid and Prostate). Results were compared with those available in literature and a fairly good agreement has been obtained. These data were then used to calculate the mean free path, half value layer, tenth value layer, effective atomic number and specific gamma-ray constant (useful for calculation of dose rate) as well. Moreover, for comparison the effective atomic number of the water has been obtained using the results of this work and using the data available in NIST database from 0.1 to 1 keV. In addition, the human tissues were compared with some tissue equivalent materials in terms of effective atomic number and specific gamma-ray constant to study the tissue equivalency from the results, the muscle-equivalent liquid with sucrose has been found to be the best tissue equivalent material for soft tissue, eye lens and brain with relative difference below 4.1%.