Adjoint ITS calculations using the CEPXS electron-photon cross sections

Continuous-energy Monte Carlo Codes are not generally suited for adjoint coupled electron-photon transport. Line radiation (e.g., fluorescence) is especially difficult to implement in adjoint mode with continuous-energy codes. The only published work on adjoint electron Monte Carlo transport is Jordan. The adjoint capability of his NOVICE code is expedited by a multigroup approximation. More recently, a Boltzmann-Fokker-Planck (BFP) Monte Carlo technique has been developed for adjoint electron transport. As in NOVICE, particle transport with BFP Monte Carlo is neither entirely continuous energy nor entirely multigroup. The BFP method has been tested in the multigroup version of MCNP and is being integrated into the ITS code package. Multigroup data produced by the CEPXS cross-section-generating code is needed to operate the BFP codes in adjoint electron-photon mode. In this paper, we present adjoint electron-photon transport results obtained with a new version of CEPXS and a new multigroup version of ITS.