Calculation of NaI(Tl) detector efficiency using ²²⁶Ra, ²³²Th, and ⁴⁰K radioisotopes: Three-phase Monte Carlo simulation study

Abstract Thallium-activated sodium iodide (NaI(Tl)) detectors can be used in gamma cameras, environmental radiation assessments, including emission levels from nuclear reactors, and analysis equipment. This three-phase investigation aimed to model a standard NaI(Tl) detector using the Monte Carlo N-Particle eXtended (MCNPX) general-purpose simulation techniques. Accordingly, was designed along with required properties. Next validation study of modelled has been performed based on experimental results for absolute efficiency values obtained 226 Ra, 232 Th, 40 K radioisotopes. Our findings indicate that are quite close values. Finally, we determination mass attenuation coefficients Ordinary concrete, Lead, Hematite-serpentine Steel-scrap concrete at 186.1, 295.22, 351.93, 609.31, 1120.29, 1764.49, 238.63, 911.2, 2614, 1460.83 keV gamma-ray energies. Additionally, according our findings, newly compatible NIST (XCOM) data. To conclude, continuous optimisation procedures strongly suggested sophisticated simulations order maintain high degree reliability. As result, it concluded is necessary measured also validated models effective instruments obtaining basic shielding parameters such as coefficients.