Thermal scattering correction for low neutron energies

Physics, Transport and Magnetic Fields
1

Dear Fluka experts,

I would like to know if by default, FLUKA activates the thermal scattering correction for H bounded in water in low energy neutron simulations for a medium containing H. I have tried to perform doses simulations with and without the LOW-MAT card with H bounded in water at 296K and it seems the results are the same.
In the .out file, I found these lines for the two simulations and I do not know if it means the thermal scattering correction is not activated or if it s more related with point-wise/multigroup treatment of thermal scattering:

  **** No bound pointwise H cross sections below  3.059E-09 GeV ****


 *** Pointwise cross sections activated for Xsec mat. #    1 HYDROGEN   ***
 *** from  3.05902E-09 GeV to  2.00000E-02 GeV ***

Thank you in advance,
Best,
Thomas

4

Hello,
Would it be possible please to address this question regarding the default physics when the LOW-MAT card is not set? Is thermal scattering correction of H in water still activated by default?

Many thanks,
Nabil

5

Dear @thomas.f

if no LOW-MAT card is specified, FLUKA is searching the materials based on the name in the order as they appear in the 10.4.1.2} List of materials for which cross sections are available in the | FLUKA. So for HYDROGEN it will select the H bounded on H2O (the first entry).

If the point wise treatment of H is activated, as it documented in the manual LOW-NEUT card Note 5, the point wise treatment is stopped above the thermal groups and then the group wise treatment is used with the S(a,b).