The beta decay of 18N and T = 2 states of mass 18
Abstract
The 18N(β -) 18O decay was observed via the 9Be( 18O, p2α) 18N reaction, utilizing helium-transport techniques and Ge(Li) spectroscopy. In addition to the previously reported β-decay to the 18O 4456 keV level ( Jπ = 1 -) branches were observed to levels at excitation energies (in keV) of 1982 ( Jπ = 2 +). 5530(2 -), 6198(1 -). 6350(2 - or 1 +), 6880(0 -), and 7771(2 -). The percentage β-branches, in order of increasing excitation energy, are 3.9 ± 1.5, 54.6 ± 1.0, 3.1 ± 0.4, 1.4 ± 0.2, 2.2 ± 0.3, 14.8 ± 0.8 and 5.0 ± 0.5. respectively, with 15 % assumed on the basis of calculations to proceed to non-γ-emitting states. These measurements allow definite assignments Jπ = 1 - for the 18N ground state and Jπ = 0 - for the 18O 6880 keV state. Additional measurements determine the 18N half-life to be T1 2 = 624 ± 12 ms. A shell-model calculation for mass 18 was carried out in a full 1ħω basis. The predictions for the T = 2 energy level spectrum and for 18N β-decay are discussed.
- Publication:
-
Nuclear Physics A
- Pub Date:
- January 1982
- DOI:
- 10.1016/0375-9474(82)90179-8
- Bibcode:
- 1982NuPhA.373...13O