The calibration of -ray spectrometer was performed by means of a set of certified standard point sources of energies that
cover the energy range of interest. The value of the absolute full energy peak efficiency "ab “ could be found by measuring
“CR" experimentally and the use of the known value of “ A “. Also, it is possible to calculate “ab" for a certain source to
detector distances (D) by using Monte Carlo [MC] simulation method.
The obtained results indicated that the fitting is identical to the experimental curve and MCNP calculations, that is both
these two methods (experimental and MCNP) can be used to extend the curve to cover the high energy range. It is possible to
drop any line energy inside the used energy range to estimate the absolute full energy peak efficiency, (for example, the energies
185.7, 1001 and 1275 keV corresponding to the sources 235U, 238U and 22Na). However, it can be estimated by using
any method from the previous methods (experimental or MCNP in addition to the fitting equation).