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It is essential to study shielding materials to protect astronauts from radiation during space missions. In the present work, a sandwich structure-shielding strategy has been used to decrease radiation exposure from the trapped radiation (low earth orbit), solar particle events (SPE), and galactic cosmic radiation (GCR). Several prominent-shielding materials such as Gadolinium (Gd), Titanium (Ti), Ferro Boron (BFe), Lithium Hydride (LiH), Lithium Borohydride (LiBH4), Lithium Aluminium Hydride (LiAlH4), Polyethylene (PE), Poly Methyl MethAcrylate (PMMA) and Polyacethylene are used for the analysis. The High Charge and Energy TRaNsport (HZETRN) code is used for the prediction of the shielding ability of these materials using the 2010 solar minimum GCR model. The dose equivalent (DE) and fluence analysis are calculated for the comparison. In the dose equivalent, analysis shows that the sandwich structure of LiBH4 + BFe + LiBH4 contributes a lower fraction of dose for neutrons and Polyacetylene + BFe + Polyacetylene shows decreased fraction of dose for protons. In addition, the sandwich structure of LiAlH4 + BFe + LiAlH4, LiBH4 + BFe + LiBH4, PMMA + BFe + PMMA, PE + BFe + Polyacetylene and PE + BFe + PMMA performs nearly the same results. It is observed that the sandwich structure using BFe alloy shows better shielding effectiveness than Gd and Ti. The fluence analysis shows that LiH + BFe + LiBH4 produces lower neutrons than other configurations. Incorporating hydrides and polymer materials into shielding systems may result in increased radiation protection against the GCR. [ABSTRACT FROM AUTHOR]

The cross-section of the 181Ta(n,2n)180Ta reaction has been measured with respect to the 197Au(n,2n)196Au monitor reaction at the incident neutron energy of 14.78± 0.20 MeV, using neutron activation analysis and off-line γ-ray spectrometric technique. The present measurement has been done at the energy where discrepant measured results are available in the EXFOR data library. The result has been compared with evaluated data libraries JEFF-3.3 and ENDF/BVII. 1. The present result has also been supported by theoretical predictions of nuclear model code TALYS1.8 and TALYS- 1.9. The uncertainty and the correlations among the measured cross-section has been studied using co-variance analysis. [ABSTRACT FROM AUTHOR]

The cross sections of the 186W(n,γ) 187W, 182W(n,p) 182Ta, 154Gd(n,2n) 153Gd, and 160Gd(n,2n) 159Gd reactions were measured at the neutron energies 5.08 ± 0.165, 8.96 ± 0.77, 12.47 ± 0.825, and 16.63 ± 0.95 MeV. Standard neutron activation analysis technique and off-line γ ray spectrometry were used for the measurement and analysis of the data. Measurements were done in the energy range where few or no measured data are available. The results from the present work are compared with the literature data based on the EX FOR compilation. The experimental results are supported by theoretical predictions using nuclear modular codes TALYS 1.8 and EMPIRE 3.2.2. The predictability of different one-dimensional models available in TALYS 1.8 and Levden models in EMPIRE 3.2.2 were tested. A detailed comparison of experimental results with theoretical model calculations is made. [ABSTRACT FROM AUTHOR]

The production cross sections for the medical isotope 99Mo were measured using the 100Mo(n,2n) reaction at average neutron energies of 10.95±0.45, 13.97±0.68, 16.99±0.53, and 20.00±0.58 MeV using offline γ-ray spectroscopy. The neutron beam was generated using the natLi(p,n) reaction at the 14UD BARC-TIFR Pelletron facility, Mumbai, India. The uncertainties in the measured data were calculated using covariance analysis. The experimental results were compared with the existing data libraries ENDF/B-VII.1, JENDL-4.0, JEFF-3.2, and CENDL-3.1. The present results were also reproduced and compared with the theoretical nuclear model codes talys-1.9 and alice-2017 using different input descriptions. A modified set of parameters were also used in talys-1.9 to fit the existing data more accurately. The present findings show a good agreement with the theoretical predictions and with the existing experimental results from the different data libraries. In addition to this, a comparative study have also been performed between the literature data of (n,p), (n,2n), and (n,a) reaction cross sections at 14.5 MeV using various systematic formulas. The outcomes of the present work are important for the advancement of medical accelerators, dosimetry, and fast reactor systems. [ABSTRACT FROM AUTHOR]

The cross sections for the 232Th(n,γ) reaction have been measured in the neutron energy range of 11-19 MeV by using activation and offline γ-ray spectrometric techniques. The neutrons of desired energy were obtained by the 7Li(p,n) reaction using a proton beam of 13-21 MeV from the 14UD BARC-TIFR Pelletron facility at Mumbai, India. The 232Th(n,γ) reaction cross sections were calculated using the computer code talys-1.8. The uncertainties in the measurement have been studied using covariance analysis of the experimental data. The results from the present work have been compared with the evaluated data of ENDF/B-VII.1 and JENDL-4.0 as well as the theoretically calculated values based on talys-1.8, and were found to be in good agreement. The outcome of the present work is important for the development of future fast reactors and accelerator driven subcritical systems (ADSs). [ABSTRACT FROM AUTHOR]