neutron(1) {
type=ENDF_ENERGY_DEPENDENT
reaction_resource="${DATA}/scale.rev00.xn28g19v8.0"
fp_yield_resource="${DATA}/origen_data/origen.rev05.yields.data"
spectrum {
type=MULTIGROUP
flux=[28R 1.0]
}
However, I cannot speak to whether it's what you're looking for in terms of physical accuracy because it does provide a warning while running. The spectrum input would need to be changed to whatever you'd want, but the number of groups needs to match the library you use in the reaction_resource input.