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nuclear420
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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?
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.
Reactor neutrons are particles that are produced in nuclear reactors through the process of nuclear fission. They are electrically neutral and have a mass similar to that of protons and electrons.
Reactor neutrons can be used to measure surface area by measuring the number of neutrons that are scattered or reflected off the surface of a material. This measurement can then be used to calculate the surface area of the material.
Surface area refers to the total area of the surface of an object, while projected cross section is the area that is projected when an object is viewed from a certain angle. In the context of reactor neutrons, surface area takes into account the scattering of neutrons in all directions, while projected cross section only considers those scattered in a specific direction.
Using reactor neutrons to measure surface area is important because it provides a more accurate and precise measurement compared to other methods. It also allows for non-destructive testing, which is crucial in industries such as nuclear power and materials science.
While reactor neutrons are a powerful tool for surface area measurements, there are some limitations. These include the availability and access to nuclear reactors, as well as the cost and expertise required to use them. Additionally, samples may need to be specially prepared for neutron scattering measurements, which can be time-consuming and may alter the surface properties of the material.