It seems something is wrong with the source.f?

i wrote a user source “source.f” to sample primary particle, i means the neutron energy is 9.441e-13 GeV, but the results show the energy of neutron is 1 GeV, why?
here is the input file:
ThermalCrossSection.inp (1.6 KB)

here is the source.f file:
source.f (9.4 KB)
the key code is:
PBEAM= SQRT (9.441d-13*9.441d-13+ TWOTWO * AM (IONID) )

here is the neutron current result cross a surface:

why the neutron energy is not the one i specialized?

sorry, the code shauld be:
PBEAM= SQRT (9.441d-13*(9.441d-13+ TWOTWO * AM (IONID)) )

but the results of producing rate of Gold 198 are different from the results of Mcnp6,
the producing rate of Gold 198 of Mcnp6 is 7.83079E-04, but the results from Fluka is
6.1280E-04, what is the reason probaly?