Mass attenuation coefficients, water and tissue equivalence properties of some tissues by Geant4, XCOM and experimental data

The mass attenuation coefficients (μ/ρ) of some tissues such as muscle (ICRU-44), adipose (ICRP) and blood (Whole) and tissue equivalents such as soft tissue model (H63C6O28N) and water have been investigated using Geant4 simulation tool kit. Appreciable variations have been noted for μ/ρ values by changing the photon energy for the studied tissues. The simulated μ/ρ have been compared with experimental data available in the literature and theoretical XCOM results in the energy region 1 keV–100 GeV, and good agreement has been observed. Also, mass attenuation coefficients relative to water have been calculated in the entire energy region to evaluate the water equivalence of the studied tissues. It is shown that a maximum difference of 8.8 % between water and mentioned soft tissue is observed at 8 keV and soft tissue is found to be a good tissue equivalent for blood and muscle tissue

Study on gamma-ray buildup factors of bismuth borate glasses

Energy absorption buildup factor (EABF) and exposure buildup factor (EBF) of bismuth borate glass systems in structure (75-x)B2O3-xBi2O3-10Na2O-10CaO-5Al2O3 (0x25) have been investigated for photon energy region between 0.015 and 15 MeV and for penetration depths of 1-40 mfp. Five parameters (G-P) fitting method has been carried out for computations procedure. The calculated values of EABF and EBF have been observed to be dependent on photon energy, penetration depths and on the concentration of Bi2O3 mol% in the glass sample. It has been found that BOB25 glass offers better gamma-ray shielding than other samples. In addition, the values of EABF and EBF have been compared and significant differences up to 8% have been noted in intermediate energy region

Mass attenuation coefficients, effective atomic numbers and electron densities of some contrast agents for computed tomography

In the clinical computed tomography (CT) examinations, a photon is attenuated as it passes a patient by tissues and contrast agents (CAs). The CM can increase the visibility of internal structures or fluids within the patient. In this work, we have investigated the photon interaction parameters of some CT contrast agents such as iotrolan, iodixanol, iohexol, ioxilan, ioversol, and iomeprol. The mass attenuation coefficients (mu/rho) of these contrast agents have been determined using Geant4 code in the energy range from 1 keV to 1 MeV for total photon interaction. The validity of the Geant4 code was verified by comparing the simulation results with those calculated by the XCOM program. A very good agreement was observed between mu/rho values obtained by both Geant4 and XCOM codes. The mu/rho values were then used to estimate the effective atomic numbers (Z(eff)) and electron densities (N-eff) for the selected CT contrast agents. It was found that the values of mu/rho, Z(eff) and N-eff depend on the photon energy and increase with increasing iodine concentration in the composition of CAs. Also, the Z(eff) values were observed in the range of 6-50 and the N-eff values were observed in the range of 2 - 21 (10(23) electron/g). The present study would be helpful to develop new CT contrast agents to serve in vivo imaging applications

Mass attenuation coefficients, water and tissue equivalence properties of some tissues by Geant4, XCOM and experimental data

433-437The mass attenuation coefficients (μ/ρ) of some tissues such as muscle (ICRU-44), adipose (ICRP) and blood (Whole) and tissue equivalents such as soft tissue model (H63C6O28N) and water have been investigated using Geant4 simulation tool kit. Appreciable variations have been noted for μ/ρ values by changing the photon energy for the studied tissues. The simulated μ/ρ have been compared with experimental data available in the literature and theoretical XCOM results in the energy region 1 keV–100 GeV, and good agreement has been observed. Also, mass attenuation coefficients relative to water have been calculated in the entire energy region to evaluate the water equivalence of the studied tissues. It is shown that a maximum difference of 8.8 % between water and mentioned soft tissue is observed at 8 keV and soft tissue is found to be a good tissue equivalent for blood and muscle tissue

Nuclear Radiation Shielding Characteristics of Some Natural Rocks by Using EPICS2017 Library

Radiation leakage is a serious problem in various technological applications. In this paper, radiation shielding characteristics of some natural rocks are elucidated. Mass attenuation coefficients (µ/ρ) of these rocks are obtained at different photon energies with the help of the EPICS2017 library. The obtained µ/ρ values are confirmed via the theoretical XCOM program by determining the correlation factor and relative deviation between both of these methods. Then, effective atomic number (Zeff), absorption length (MFP), and half value layer (HVL) are evaluated by applying the µ/ρ values. The maximum μ/ρ values of the natural rocks were observed at 0.37 MeV. At this energy, the Zeff values of the natural rocks were 16.23, 16.97, 17.28, 10.43, and 16.65 for olivine basalt, jet black granite, limestone, sandstone, and dolerite, respectively. It is noted that the radiation shielding features of the selected natural rocks are higher than that of conventional concrete and comparable with those of commercial glasses. Therefore, the present rocks can be used in various radiation shielding applications, and they have many advantages for being clean and low-cost products. In addition, we found that the EPICS2017 library is useful in determining the radiation shielding parameters for the rocks and may be used for further calculations for other rocks and construction building materials

Electric Poling Effect on Piezocatalytic BaTiO3/Polymer Composites for Coatings

BaTiO3-polymer paint composites were fabricated to examine piezocatalysis activities. Dye degradation and antibacterial activities were recorded under ultrasonication. The effect of polarization was also examined for the catalysis process. There were significant enhancements in catalysis performance in the poled sample; 80–90% dye degradation was recorded (240 min) in poled samples of BaTiO3-polymer paint composites. The above observations indicate that these composites can be utilized as coatings for self-cleaning applications

Electric Poling Effect on Piezocatalytic BaTiO₃/Polymer Composites for Coatings

BaTiO3-polymer paint composites were fabricated to examine piezocatalysis activities. Dye degradation and antibacterial activities were recorded under ultrasonication. The effect of polarization was also examined for the catalysis process. There were significant enhancements in catalysis performance in the poled sample; 80–90% dye degradation was recorded (240 min) in poled samples of BaTiO3-polymer paint composites. The above observations indicate that these composites can be utilized as coatings for self-cleaning applications

Structural, Magnetic and Gas Sensing Activity of Pure and Cr Doped In2O3 Thin Films Grown by Pulsed Laser Deposition

Pure In2O3 and 6% Cr-doped In2O3 thin films were prepared on a silicon (Si) substrate by pulsed laser deposition technique. The obtained In2O3/In2O3:Cr thin films structural, morphological, optical, magnetic and gas sensing properties were briefly investigated. The X-ray diffraction results confirmed that the grown thin films are in single-phase cubic bixbyte structure with space group Ia-3. The SEM analysis showed the formation of agglomerated spherical shape morphology with the decreased average grain size for Cr doped In2O3 thin film compared to pure In2O3 film. It is observed that the Cr doped In2O3 thin film shows the lower band gap energy and that the corresponding transmittance is around 80%. The X-ray photoelectron spectroscopy measurements revealed that the presence of oxygen vacancy in the doped In2O3 film. These oxygen defects could play a significant role to enhance the sensing performance towards chemical species. In the magnetic hysteresis loop, it is clear that the prepared films confirm the ferromagnetic behaviour and the maximum saturation value of 39 emu/cc for Cr doped In2O3 film. NH3 gas sensing studies was also carried out at room temperature for both pure and Cr doped In2O3 films, and the obtained higher sensitivity is 182% for Cr doped In2O3, which is about nine times higher than for the pure In2O3 film due to the presence of defects on the doped film surface

Effect of Poling on Multicatalytic Performance of 0.5Ba(Zr_0.2Ti_0.8)O₃-0.5(Ba_0.7Sr_0.3)TiO₃ Ferroelectric Ceramic for Dye Degradation

Ferroelectric materials with a spontaneous polarization are proven to be potential multicatalysts in water remediation applications. The composition of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Sr0.3)TiO3 (BST-BZT) was examined for photocatalysis, piezocatalysis, and piezo-photocatalysis processes by degrading an azo dye named methylene blue (MB). Generally, dis-aligned dipoles restrict the catalytic activities due to which the BST-BZT powder sample was poled by the corona poling technique. Coupled piezocatalysis and photocatalysis process, i.e., the piezo-photocatalysis process has shown maximum dye degradation. There was a significant improvement in degradation efficiency by using a poled BST-BZT sample compared to the unpoled sample in all processes, thus the results suggest an extensive scope of poled ferroelectric ceramic powder in the catalysis field