LIST OF FIGURES
FiMr page
1-1 Comparison between thicknesses required to attenuate different percentages of
primary photons and Rcs range for maximum energy secondary electrons
produced by the same beam ................. ...............33.____.....
1-2 Comparison between thicknesses required to attenuate different percentage of
primary photons and average range for maximum energy secondary electrons
produced by the same beam ................. ...............33.____.....
2-1 60C0 unit (left: Mesh distribution generated by PENTRAN package; Right: MCNP5
Cell/Surface schematic input) ................ ...............38........... ....
2-2 60C0 y-rays 3-D Groups 1,2 3 and 4 scalar flux computed by PENTRAN with the
CEPXS gamma cross section library ................. ......... ...............40.....
2-3 S12 (Level Symmetric) and S42 (Legendre-Chebychev) quadrature first octants (with
21 and 231 directions/ octant respectively) .............. ...............41....
2-4 60Co y-ray 3-D Group 1 scalar flux distribution for x-level depths at 0 cm, 5 cm, 10
cm and 15 cm, computed by PENTRAN with the CEPXS gamma cross section
library ................. ...............42.................
2-5 60Co y-ray 3-D Group 1 scalar flux distribution for x-level depths at 0 cm, 5 cm, 10
cm and 15 cm, computed by PENTRAN with the CEPXS gamma cross section
library; an S42 angular quadrature (1848 directions) with P3 Scattering anisotropy ..........43
2-6 Scalar flux distributions using S12, S22, S32, and S42 with P3 Scattering anisotropy in
PENTRAN using the BUGLE-96 gamma library .............. ...............44....
2-7 60C0 model spatial meshing, axial level............... ...............47.
2-8 Scalar flux comparison of variation in the interval of 3-D mesh cells containing air;
fine meshes of 1 cm size (along each axis) in air proved to be best in providing high
detail flux distribution............... ..............4
2-9 Scalar flux distributions generated by PENTRAN for a single energy group of each
library using the MCNP5 solution as the reference case. ................. .................5
2-10 Relative deviation of energy group 1 discrete ordinates results with Monte Carlo
results ............... ...............52........_ ......
2-11 Absorbed dose rate comparison between SN method using kerma approximation and
MC techniques using F6 tally, MC statistical uncertainty were less than 3% on
average ................. ...............53........ ......