Deceleration of neutrons to ultracold

Hello, dear experts! Please, can I suggest, is it correct to use NeutronHPphysics to model the process of neutron slowing down to 10^(-7) eV? I have considered the UCN example, but there we are talking about ultracold neutrons and their reflection. My question is more about the process of neutron energy loss and correct consideration of all physical processes.
In addition, there is a question about helium for neutron deceleration. In simulations for neutron deceleration, how is it correct to define superfluid helium? Is it the same as specifying ordinary helium at cryogenic temperature?

This is the first time I am asking a question on the forum,
I would be very grateful for your advice!


hello ,

in the recent public version of Geant4 11.3beta the option HPT is provided, which support very low-energy transport. The accuracy of results depend on inclusion/not inclusion of thermal data in the distribution. If special thermal data per material is not available, then element data are used. In the last case, the state of a material is not considered.

Sampling of energy loss is determined by accuracy of elastic data. There is also neutron capture process, for limited number of targets inelastic is non-zero at low energy, also fission may be non-zero.

VI