Study of exposure buildup factors with detailed physics for cobalt-60 gamma source in water, iron, and lead using the MCNPX codeMustafa Mohammad Rafiei and Hossein Tavakoli-AnbaranEur. Phys. J. Plus, 133 12 (2018) 548DOI: https://doi.org/10.1140/epjp/i2018-12355-8