The discussion revolves around the nature of neutron interactions with atomic nuclei in a reactor context, specifically whether neutrons perceive the surface area of nuclei rather than the projected cross section. The conversation touches on theoretical aspects, quantum mechanics, and the implications of neutron energy levels.
Participants express differing views on the interpretation of neutron interactions, with no consensus reached on whether neutrons see surface area or projected cross section. The discussion remains unresolved regarding the implications of neutron energy on these interactions.
Participants reference specific neutron cross section data and suggest that the relationship between cross sections and nuclear surface area is complex and not fully understood. There are indications of unresolved mathematical or conceptual steps in the discussion.
That really depends on the energy of the neutron. For high energy (MeV range) neutrons, e.g., those emitted during fission, the one considers 'potential scattering'. At much lower (thermal) energies, < 1 eV, and particularly in the 0.025 eV range, then the cross-section is more or less determined by the nature of the particular nucleus encountered. That's were QM play becomes dominant. In between though (1 eV-10 keV range), QM is a factor in resonance scattering/absorption.nuclear420 said:My professor told me that the neutrons in a reactor see the surface area of nuclei, and not the the projected cross section. That really doesn't make intuitive sense. Is he right?
\nuclear420 said:My professor told me that the neutrons in a reactor see the surface area of nuclei, and not the the projected cross section. That really doesn't make intuitive sense. Is he right?
Clem-clem said:\
I don't think he was talking about the size of the cross section, which depends on details other than the effective area. Possibly what he meant was that the slow neutrons are in an L=0 (spherically symmetric) state with respect to the nucleus so they interact at the entire surface.