Mass and Spectroscopic Measurements in the Completed Mass-21 and -37 Isospin Quartets

Low-lying $T=\frac{3}{2}$ levels of the mass-21 isospin quartet (${}_{}{}^{21}{}_{}{}^{}\mathrm{F}$, ${}_{}{}^{21}{}_{}{}^{}\mathrm{Ne}$, ${}_{}{}^{21}{}_{}{}^{}\mathrm{Na}$, and ${}_{}{}^{21}{}_{}{}^{}\mathrm{Mg}$) and of three members of the mass-37 quartet (${}_{}{}^{37}{}_{}{}^{}\mathrm{Ar}$, ${}_{}{}^{37}{}_{}{}^{}\mathrm{K}$, and ${}_{}{}^{37}{}_{}{}^{}\mathrm{Ca}$) have been investigated. An improved particle-identification system which employs two transmission ($\Delta E$) detectors and one stopping ($E$) detector and which permits the measurement of low-yield nuclear reactions was used to determine the masses of the $T_z=-\frac{3}{2}$ nuclei ${}_{}{}^{21}{}_{}{}^{}\mathrm{Mg}$ and ${}_{}{}^{37}{}_{}{}^{}\mathrm{Ca}$ via the (${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^6{}_{}{}^{}\mathrm{He}$) reaction on ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ at $E_{{}_{}{}^4{}_{}{}^{}\mathrm{He}}=56\mathrm{}$ MeV. The complete experimental procedures followed in these three-neutron transfer investigations are discussed. The first three $T=\frac{3}{2}$ levels in ${}_{}{}^{21}{}_{}{}^{}\mathrm{Ne}$ were established by a simultaneous study of the ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}(d, t){}_{}{}^{21}{}_{}{}^{}\mathrm{Ne}$ and ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}(d, {}_{}{}^3{}_{}{}^{}\mathrm{He}){}_{}{}^{21}{}_{}{}^{}\mathrm{F}$ reactions at 39.6 MeV, while the ${}_{}{}^{22}{}_{}{}^{}\mathrm{Na}(d, t){}_{}{}^{21}{}_{}{}^{}\mathrm{Na}$ reaction at 42 MeV was utilized to observe the lowest $T=\frac{3}{2}$ level in ${}_{}{}^{21}{}_{}{}^{}\mathrm{Na}$. Excitation energies of the lowest $T=\frac{3}{2}$ levels in ${}_{}{}^{37}{}_{}{}^{}\mathrm{K}$ and ${}_{}{}^{37}{}_{}{}^{}\mathrm{Ar}$ were determined via the ${}_{}{}^{39}{}_{}{}^{}\mathrm{K}(p, t){}_{}{}^{37}{}_{}{}^{}\mathrm{K}$ and ${}_{}{}^{39}{}_{}{}^{}\mathrm{K}(p, {}_{}{}^3{}_{}{}^{}\mathrm{He}){}_{}{}^{37}{}_{}{}^{}\mathrm{Ar}$ reactions induced by 45-MeV protons. Data from the complete quartets were used to test the isobaric-multiplet mass equation and the various predictions of the masses of neutron-deficient nuclei.