Nuclear Energy Levels of F19, F21, Ne22, and Ne24

Abstract

A 16-in. radius, 180° double-focusing magnetic spectrometer was used to investigate the nuclear energy levels of ${\mathrm{F}}^{19}$, ${\mathrm{F}}^{21}$, ${\mathrm{Ne}}^{22}$, and ${\mathrm{Ne}}^{24}$ by analysis of protons and alpha particles produced by ($t, p$) and ($t, \alpha$) reactions with natural neon and with ${\mathrm{Ne}}^{22}$ gas targets. Between excitation energies of 2.8 and 6.5 Mev, new levels in ${\mathrm{F}}^{19}$ were found at 5.102, 5.539, 5.628, 5.937, and 6.169 Mev. Previously reported levels at 3.29, 4.48, and 4.95 Mev were not observed. Up to an excitation energy of 4.3 Mev in ${\mathrm{F}}^{21}$, new levels were seen at 3.451, 3.509, 3.635, 3.977, 4.056, and 4.158 Mev, while the four previously known lower states at 0.285, 1.104, 1.743, and 2.047 Mev were confirmed. The mass of ${\mathrm{F}}^{21}$ was determined to be 21.006624±0.000011 amu (${\mathrm{O}}^{16}$ standard); $\mathrm{}(M-A)=6.168\mathrm{}\pm 0.010$ Mev. In ${\mathrm{Ne}}^{22}$ 38 excited states were observed up to an excitation of 9.4 Mev. Levels at 1.277, 3.343, and 4.473 Mev were confirmed, while a previously reported level at 4.9 Mev was not observed. Energy levels in ${\mathrm{Ne}}^{24}$, up to an excitation energy of 6.4 Mev, were found at 1.986, 3.873, 3.962, 4.764, 4.886, 5.576, (5.641), and 6.030 Mev. The mass of ${\mathrm{Ne}}^{24}$ was determined to be 24.001238±0.000011 amu (${\mathrm{O}}^{16}$ standard); $\mathrm{}(M-A)=1.153\mathrm{}\pm 0.010$ Mev. Standard deviations in the values for the excitation energies vary from 0.015 to 0.025 Mev. Some representative cross sections are reported.