Nuclear Energy Levels of N17, O18, and O20

Abstract

The reactions ${\mathrm{O}}^{18}(t, \alpha ){\mathrm{N}}^{17}$, ${\mathrm{O}}^{16}(t, p){\mathrm{O}}^{18}$, and ${\mathrm{O}}^{18}(t, p){\mathrm{O}}^{20}$ have been studied with a 180°, double-focussing magnetic spectrometer. The measured energy levels of ${\mathrm{N}}^{17}$ up to 4.3 Mev are at 1.374, 1.851, 1.906, 2.536, 3.132, 3.212, 3.652, and 4.010 Mev. The measured energy levels of ${\mathrm{O}}^{18}$ up to 5.2 Mev are at 3.560, 3.639, 3.925, 4.457, and 5.084 Mev. The measured energy levels of ${\mathrm{O}}^{20}$ up to 4.6 Mev are at 1.682, 4.091, and 4.449 Mev. Standard deviations of 15 to 25 kev have been assigned to these excitation energies. The $Q$ value for ${\mathrm{O}}^{18}(t, \alpha ){\mathrm{N}}^{17}$ was determined to be 3.872±0.015 Mev, which leads to a mass for ${\mathrm{N}}^{17}$ of 17.013 856±0.000 017 amu. The $Q$ value for ${\mathrm{O}}^{18}(t, p){\mathrm{O}}^{20}$ was determined to be 3.086±0.015 Mev, which leads to a mass for ${\mathrm{O}}^{20}$ of 20.010 430±0.000 017 amu. Reaction cross sections at 30° lab angle and 2.6-Mev triton energy are presented for each level.