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mctools / ncrystal

NCrystal : a library for thermal neutron transport in crystals and other materials
https://mctools.github.io/ncrystal/
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Add single crystal model cutoff #43

Open tkittel opened 3 years ago

tkittel commented 3 years ago

As pointed out during a seminar today, there is really no need to spend a huge amount of CPU time in single crystal models at very high neutron energies. We should consider a generic cutoff value (e.g. lambda<0.01Aa) beyond which scattering would either have 0 cross section, use a power cross section, or something else (i.e. scaling xs as lambda^2 and using isotropic scatterings?).

Perhaps the cutoff should be dynamic...? Or related to the values of dcutoff/sccutoff?

Perhaps 0.01Aa unless pushed further down by low dcutoff/sccutoff values? I.e. 0.01 but at most half of min(dcutoff/sccutoff)?

tkittel commented 5 months ago

We can perhaps simply have the cutoff at 0.1*sccutoff? It would be best of course, if we could push the missing parts into the PCBragg instance used for the sccutoff.