Dear FLUKA Experts,
I am trying to calculate microdosimetric distribution of 14 MeV neutron using DETECT card. I have used “Precision” default, “LOW-Neut”.
But the calculated distribution is different from the expected one.
This may be due to the reason that the produced heavy recoil are not transported explicitly.
How to overcome this problem. What PHYSICS setting I should use to get correct microdosimetric distribution for 14 MeV neutron.
As you are aware, no secondary charged particles are explicitly produced and transported following incident neutron reactions by neutrons below 20 MeV (“low-energy neutrons”). Furthermore, energy deposition is estimated via kerma factors and is entirely deposited at the point of the interaction (since no secondary particle is there to carry energy away). This is not a default setting that you can somehow change via the PHYSICS or any other card, but rather a structural feature of the code, which may make your study difficult. A few light nuclei are an exception to this, see Chapter 10 of the manual.
In addition to the above, if you are studying effects at the sub-micron scale, be aware that codes such as FLUKA and MCNP cannot reliably treat the transport of charged particles at this scale. You may instead opt to use Geant4 and the Geant4-DNA extension that is specially developed for nanoscale (biological) studies. For the particular case of neutrons, thin/low-density layers can pose additional challenges in FLUKA (see Section 10.1.1 of the manual)
I hope this somehow clarifies the situation for you and helps you to better plan your study.