Low energy neutrons at very low temperature

Dear Fluka experts
I would like to calculate the activation of some metallic components
(mostly iron and copper), kept at the temperature of liquid helium
(about 2 K), after the irradiation due to a proton beam.
I see in the manual that I can select, for the low energy
neutron cross sections of my interest, only the temperatures of
 293 or 87 Kelvin.
According to your experience, what are the possible biases if I select the
87 K case?
Are these low energy neutron cross sections relevant for the
activation calculation?

Kind regards
         Arturo Busetti
Received on Wed Apr 16 15:03:25 2008