Odd-Even Dependence of Nuclear Level Density Parameters

Previously reported experimental ($n, p$) and ($n, \alpha$) cross-section data have been analyzed to determine nuclear level density parameters for the Fermi gas model which best fit the experimental data for target nuclei ranging in mass number from 9 to 64. Level density parameters for odd-odd and even-even nuclei are obtained in terms of those for the better-known odd-$A$ values. The results of this analysis are $\frac{1}{2}{C}_{\mathrm{o}\mathrm{d}\mathrm{d}-\mathrm{o}\mathrm{d}\mathrm{d}}=C_{\mathrm{odd}A}=5\mathrm{}{C}_{\mathrm{e}\mathrm{v}\mathrm{e}\mathrm{n}-\mathrm{e}\mathrm{v}\mathrm{e}\mathrm{n}}$. Brief mention is made of the direct-interaction contribution in ($n, p$) reactions. Experimental measurements which would be most beneficial for further theoretical analysis are suggested.