ABSTRACT
@#<b>Objective</b> To compare the precision and efficiency of computing the specific absorbed fraction (SAF) of a reference human with two grid methods in MCNP6.0. <b>Methods</b> Based on the adult female reference voxel phantom provided by the International Commission on Radiological Protection, assuming the liver as the source organ emitting single-energy photons (0.5 MeV), the SAF of each target organ/tissue was calculated by using the mesh method and repeated structure lattice method with the F4, F6, and *F8 tally cards in MCNP6.0. We compared the methods by assessing the relative deviation of SAF and computing time for 27 organs/tissues. <b>Results</b> Compared with reported data, the absolute values of relative deviations of SAF values for all the organs/tissues were less than 5%, except for the eye lens and skin. By using the repeated structure lattice-based *F8 tally, the relative deviations of SAF values of the organs/tissues were all smallest, but with the longest computing time. The computing time of the mesh-based F4 tally was slightly longer than that of the repeated structure lattice-based F6 tally, which was shortest. <b>Conclusion</b> The *F8 tally simultaneously simulating primary and secondary particle transport showed the highest precision. The mesh tally requireda longer computing time than the lattice tally when using the same tally card.