this work focused on the use of 16 energy groups for a flat weighted 8 MeV high energy source
term, the parallel EDK-SN computation could be parsed to a maximum of 16 parallel processors.
Near linear speedups were achieved.
The parallel code follows the following steps in executing the EDK-SN methodology for
total dose calculation:
Initiate the code on all processors for sets of energy groups, up to one group per
processor
Sort the locally parallel-allocated fine mesh distributions into a global monotone
increasing mesh distributions
Create Energy group dose matrix aliased to the location of the DDVs
Translate material tags into densities for later calculation
Project the Group-dependent EDK based on the group current vector and material at the
DDV
Scale group dose using group scalar flux, correcting for densities at material interfaces
Use MPI-REDUCE to sum all doses for the phase space across the parallel processing
grid
4.8 Discussion and Findings
We examined a new EDK-SN methodology of coupling pre-computed Monte Carlo based
electron absorbed dose kernels (EDKs) with the discrete ordinates (SN) solutions to achieve
accurate absorbed doses for megavolt energy photon scenarios, since charged particle
equilibrium fails and full photon-electron physics must be accounted for to fully attribute
absorbed dose. The EDK-SN methodology was compared with the Monte Carlo method and
shown to give results consistent within the statistical uncertainty of the absorbed dose computed
using Monte Carlo calculations.
By following the EDK-SN approach, the absorbed dose applied to tissue from any
incident external high energy photon beam (pencil, fan, areal, etc) can therefore be readily
determined based on a coupling of the deterministic SN photon transport solution from the
PENTRAN code using the EDK-SN methodology. As a result, this research renders the first