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

Low-lying T=3/2 levels of the mass-21 isospin quartet (²¹F, ²¹Ne, ²¹Na, and ²¹Mg) and of three members of the mass-37 quartet (³⁷Ar, ³⁷K, and ³⁷Ca) have been investigated. An improved particle-identification system which employs two transmission (ΔE) detectors and one stopping (E) detector and which permits the measurement of low-yield nuclear reactions was used to determine the masses of the Tz=-3/2 nuclei ²¹Mg and ³⁷Ca via the (³He, ⁶He) reaction on ²⁴Mg and ⁴⁰Ca at E_⁴He=56 MeV. The complete experimental procedures followed in these three-neutron transfer investigations are discussed. The first three T=3/2 levels in ²¹Ne were established by a simultaneous study of the ²²Ne(d, t)²¹Ne and ²²Ne(d, ³He)²¹F reactions at 39.6 MeV, while the ²²Na(d, t)²¹Na reaction at 42 MeV was utilized to observe the lowest T=3/2 level in ²¹Na. Excitation energies of the lowest T=3/2 levels in ³⁷K and ³⁷Ar were determined via the ³⁹K(p, t)³⁷K and ³⁹K(p, ³He)³⁷Ar 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.