Neutron resonance spectroscopy: Magnesium

The total neutron cross sections vs energy to 500 keV, measured using high purity samples of nutural Mg, show four main strong levels plus a weak level at 498 keV. An $R$-matrix fit is mainly established by the four strong levels having ($E_0,A,l,J,{\Gamma }_n$) values (19.90, 25, 0, 2, 1.79 ± 0.18), (83.50, 24, 1, 3/2, 7.6 ± 0.5), (265.2, 24, 1, 1/2, 90 ± 5), and (426.3, 24, 1, 3/2, 23.2 ± 2.3), with $E_0$ and ${\Gamma }_n$ in keV. Using a channel radius of 5 fm, we obtain a $p$ strength function for ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$, $10{}_{}{}^4{}_{}{}^{}S_1^{}{}_{}{}^{}=\left({10.5}_{-4.9\mathrm{}}^{+11.8\mathrm{}}\right)$ to 500 keV.