Spin-parity assignments to yrast states of 42K

Abstract

Abstract Low-lying states of 42 K have been investigated with the 26 Mg( 18 O, pnγ) 42 K reaction at beam energies of 25 and 34 MeV. The experiments consisted of γ-ray angular distribution, γ-γ angular correlation and linear polarization measurements. A high-resolution large-volume Ge(Li)NaI(Tl) Compton-suppression spectrometer, Ge(Li) detectors of about 25% efficiency and a three-crystal Ge(Li) Compton polarimeter were used. Unambiguous spin-parity assignments of J π =3 − , 4 − , 3 − , 5 − , 4 + , 6 + and 7 + for the 42 K levels at E x =106.78±0.02, 258.11±0.12, 638.4±0.2, 698.79±0.17, 1143.2±0.2, 1375.5±0.2 and 1947.2±0.3 keV, respectively, are obtained. Two levels at E x =1143 and 1538.3±0.4 keV, hitherto unobserved in γ-ray work, are established. Multipole mixing ratios and transition strengths for several transitions are reported.