“…The GP fitting formula is known to be accurate within the estimated uncertainty (< 5%), and Harima carried out an extensive historical review and reported the current gamma photon build-up factors and applications (Harima, 1993). Various researchers have investigated gamma-ray build-up factors in different materials fly-ash, concretes (Brar et al, 1994;Singh et al, 2010;Badiger, 2012a, 2012b), solvents (Parjit et al, 2008), polymers (Tejbir et al, 2010;, human tissues , soils & ceramic (Sandeep and Gurdeep, 2012;Jasbir et al, 2012;Tejbir et al, 2013), and fly ash (Sukhpal et al, 2010), which showed that GP fitting is a very useful method for estimation of exposure and energy absorption build-up factors.…”