FW/CADIS-$Ω$: An angle-informed hybrid method for deep-penetration radiation transport
This work addresses the need for efficient variance reduction in deep-penetration radiation shielding problems with strong angular anisotropies, but it is an incremental improvement over existing methods.
The paper presents CADIS-Ω, a new method for generating variance reduction parameters in deep-penetration radiation transport that incorporates angular anisotropies. In a concrete labyrinth test problem, CADIS-Ω outperformed the standard CADIS method while maintaining accuracy.
A new method for generating variance reduction parameters for strongly anisotropic, deep-penetration radiation shielding studies is presented. This method generates an alternate form of the adjoint scalar flux quantity, $ϕ^{\dagger}_Ω$, which is used by both CADIS and FW-CADIS to generate variance reduction parameters for local and global response functions, respectively. The new method, called CADIS-$Ω$, was implemented in the Denovo/ADVANTG software suite, and results are presented for a concrete labyrinth test problem. Results indicate that the flux generated by CADIS-$Ω$ incorporates localized angular anisotropies in the flux effectively. CADIS-$Ω$ outperformed CADIS in the test problem while obtaining accurate results. This initial work indicates that CADIS-$Ω$ may be highly useful for shielding problems with strong angular anisotropies. A future test plan to fully characterize the new method is proposed, which should reveal more about the types of realistic problems for which the CADIS-$Ω$ will be suited.