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(25) Sodium is used as a coolant in certain types of nuclear reactors. 100% of all sodium is composed of Na-23. One sees the first resonance in Na-23 at a neutron energy of 2.85 kev. The peak of this resonance has a cross section of 400 b and it has a full width at half maximum of 0.411keV (that is, I = 0.411 kev). a) This resonance corresponds to an excited state in what nucleus? b) What is the energy level of this excited state? c) At what neutron energy (or energies) will this resonance cross section decrease to 200b? d) What are the absorption, scattering, and total microscopic cross sections for Na-23 for neutrons having energies of 400 eV? e) Estimate the microscopic scattering using the 4tR2 approximation