it appears impossible to calculate backward detector response in openMC, while MCNP achieves this feat through the utilization of multigroup and adjoint capabilities.
It would be a welcomed addition if developers could consider incorporating this feature into openMC.
Hi @basit and welcome to the community. Can you let me know which card(s) in MCNP would be used to achieve this capability you are referring to?
We can use the MGOPT card to achieve multigroup calculations in MCNP. This card is specifically designed for multigroup calculations and can also be used as follows:
MGOPT a 30
In this context, “a” stands for adjoint calculation, and 30 represents the number of energy groups in the multigroup library. Another card is CUT:n to define upper energy limit for backward transport process.
For further details, you can refer to this helpful link: MCNP: Multigroup/adjoint capabilities (Technical Report) | OSTI.GOV and the MCNP manual (MGOPT MULTIGROUP ADJOINT TRANSPORT OPTION).