Evaluation of photon shielding properties for new refractory tantalum-rich sulfides Ta9(XS3)2 alloys: A study with the MCNP-5

Abstract

We use MCNP-5 code to simulate the mass attenuation coefficient, MAC, of a new series of refractory tantalum-rich sulfides Ta9(XS3)2, where (X ≡ Fe, Co, Ni) to be used in ionizing radiation attenuation applications. The samples were prepared earlier using the conventional solid-state reaction. The densities of the samples range from 10.32 to 10.52 g/cm3.The simulated results show a decent correlation with the XCOM data, with a relative difference of 0.00 % to 3.59 % in all samples, giving confidence in the accuracy of the current results. The Kolmogorov-Smirnov (K-S) test confirmed, statistically, that the simulated data matched the XCOM data very well, with the maximum vertical deviation (Dmax) ranging between 0.10 % and 0.14 % and p-value of 0.99 in all samples. The obtained MAC was used to derive different radiation parameters. The linear attenuation coefficient (LAC), half-value layer (HVL), mean free path (MFP), transmission factor (TF), and radiation protection efficiency (RPE) for all alloys examined. The results are then compared to the data published in the literature. For instance, the calculated HVL values of the investigated samples ranging 0.5196, 0.5116, and 0.5097 cm at 0.5 MeV, for X = Fe, Co, and Ni respectively, whereas Pb has a value of 0.3806 cm at the same energy. Besides, we deduced that Ta9(XS3)2 system have higher MFPs than Pb, indicating that Pb still has better radiation shielding properties. They are, however, much lower than the MFP for many published materials such as MgB2, FeAs, CrTe, and PbTe. Finally, the analysis also reveals that the RPE at 3 cm thickness is 98.17 %, 98.28 %, and 98.31 % for the X = Fe, Co, and Ni samples respectively. That means these samples can reduce about 98 % of the 0.5 MeV incident gamma beam if the sample thickness is only 3 cm. Our motivation, as with many other investigations into ionizing radiation shielding, is to find a material with the required properties, such as high density, chemical stability, good durability, low coast materials, and ease of synthesis. Our findings suggest that the Ta9(XS3)2 are promising alloys for use in ionizing radiation shielding applications.