Nuclear Data Sheets for A=24

Abstract

Evaluated spectroscopic data and level schemes from radioactive decay and nuclear reaction studies are presented for 24N, 24O, 24F, 24Ne, 24Na, 24Mg, 24Al, and 24Si. This evaluation for A=24 supersedes the earlier one by R. B. Firestone (2007Fi14).Highlights of this evaluation are the following:In 24O, the 7.4- and 7.65-MeV groups reported in 1H(24O,p′) (2012Ts03) and 9Be(26F,nX) (2011Ho05), respectively, are considered as separate states in this evaluation, since the former one was observed to decay by only one neutron emission to 23O, while the latter one by two sequential neutrons to 22O. Based on assigned configurations, the 7.4- and 7.6-MeV groups are tentatively assigned negative and positive parities, respectively. Additional study would be useful to determine if these states are same or different.In 24Na, 2014Fi01 (n,γ) proposed Jπ=(0,1,2)− for 4048.8 keV level based on weaker population from the capture state (Jπ=1+,2+) and mentioned to reexamine the Jπ=0+ assignment, suggested in earlier evaluations (1990En08, 2007Fi02).This evaluation includes the first observation of E0 transition, strength ρ2(E0)=0.380 70, for the 6432 keV transition from 0+ state at 6432 to 0+ g.s. in 24Mg reported in 2020Do10. Authors proposed the first-excited 0+ state of 24Mg to be superdeformed.In 24Al, the excited level energies deduced from (3He,t) measurements reported by different research groups vary significantly and it was not clear if some of those levels were same or different. Additional measurements are needed.