Fe-nanoparticle effect on polypropylene for effective radiation protection: Simulation and theoretical study

An evaluation of the gamma-neutron shielding capabilities of polymer nanocomposite materials based on polypropylene and iron nanoparticles is presented in this study. The chemical composition of the materials is (100-x) PP-Fex, (where x = 0.1, 0.3, 0.5, 1, 2 and 5 wt percent). For the proposed polymer samples with photon energies ranging from 30 to 2000 KeV, the mass attenuation coefficient (MAC), a crucial parameter for studying gamma-ray shielding capability, was calculated using the Geant4 Monte Carlo code. Results were compared with those predicted by EpiXS. The values of the Geant4 code and the EpiXS software were both found to be in excellent agreement. Using the mass attenuation coefficient values, we determined the linear attenuation coefficients, electron density, effective atomic number, and half value layer for all the samples. The shielding properties of the polymer samples were also evaluated by estimating both the fast neutron removal cross-section and the mean free path of the fast neutron at energies between 0.25 and 5.5 keV. The study's findings indicate a positive correlation between the Fe nanoparticle content and the gamma-ray shielding performance of PP-Fe polymer samples. Out of the several glasses that were evaluated, it was found that the PP-Fe5 polymer sample demonstrates the highest efficacy in terms of gamma-ray shielding. Moreover, the polymer sample PP-Fe5, which consists of 5 mol% of iron (Fe), exhibits the highest value of ∑R (1.10650 cm-1) and the lowest value of the mean free path for fast neutrons. This indicates that the PP-Fe5 possesses better gamma-neutron shielding efficiency.

Mechanic-elastic properties and radiation attenuation efficiency of TeO2/WO3/K2O composite glass systems for nuclear and medical application

WO3 effects on neutron and ionizing radiation defending factors of ternary tellurite-based glass blocks with molecular formula 80TeO2 -(20-x)WO3 - xK2O; x = 0-20 mol% (denoted as TKW-glass) has been reported via Phy-X theoretical calculations and Geant4 simulation code. Correlations between shielding factors and kinetics properties of the investigated glasses at different photon energy have been examined. The highest values of mass (MAC) attenuation coefficient were noted at 15 keV of the examined TKW-glass materials with the values of 38.408, 44.388, 49.855, 54.872, 59.492 cm2/g for TKW-0, TKW-5, TKW-10, TKW-15, and TKW-20, respectively. Generally, these values of the TKW-glasses obey the sequence: (TKW-0)MAC< (TKW-5)MAC < (TKW-10)MAC < (TKW-15)MAC < (TKW-20)MAC. The highest mean free path (MFP) values of TKW-glasses were registered at 15 MeV with the values of 6.101, 5.591, 5.097, 4.647, and 4.302 cm for TKW-0, TKW-5, TKW-10, TKW-15, and TKW-20, respectively. The two parameters half value layer (HVL) and MFP follow the pattern: (TKW-0)HVL, MFP > (TKW-5)HVL,MFP > (TKW-10)HVL,MFP > (TKW-15)HVL,MFP > (TKW-20)HVL,MFP. The maximum values of effective atomic number (EAN) took place at gamma energy of 15 keV corresponding to 44.35, 48.86, 52.63, 55.83, and 58.58 for TKW-0, TKW-5, TKW-10, TKW-15, and TKW-20, respectively. The trend of the buildup factors was similar for all of the glass specimens. The fast neutron removal cross-section (Σ R ) enhanced as WO3 content increased in the specimens. Thus, the peaked value of Σ R is 0.1059 cm-1 was noted in the TKW-20 sample. Mechanical properties, neutron and γ-rays protection parameters were observed to improve with enhanced WO3 mol% in the TKW-glasses. The current results bear their utilization for neutron and gamma protection purposes.

Calculation of extrapolation curves in the 4π(LS)β-γ coincidence technique with the Monte Carlo code Geant4

At LNE-LNHB, a liquid scintillation (LS) detection setup designed for Triple to Double Coincidence Ratio (TDCR) measurements is also used in the β-channel of a 4π(LS)β-γ coincidence system. This LS counter based on 3 photomultipliers was first modeled using the Monte Carlo code Geant4 to enable the simulation of optical photons produced by scintillation and Cerenkov effects. This stochastic modeling was especially designed for the calculation of double and triple coincidences between photomultipliers in TDCR measurements. In the present paper, this TDCR-Geant4 model is extended to 4π(LS)β-γ coincidence counting to enable the simulation of the efficiency-extrapolation technique by the addition of a γ-channel. This simulation tool aims at the prediction of systematic biases in activity determination due to eventual non-linearity of efficiency-extrapolation curves. First results are described in the case of the standardization (59)Fe. The variation of the γ-efficiency in the β-channel due to the Cerenkov emission is investigated in the case of the activity measurements of (54)Mn. The problem of the non-linearity between β-efficiencies is featured in the case of the efficiency tracing technique for the activity measurements of (14)C using (60)Co as a tracer.