A study of²²³Th levels populated by alpha -decay

Abstract

Low spin states of 22'Th have been populated via a-decay. The parent nucleus ("' U, l,n-1 min) was formed in the reaction zoaPb(22Ne, 3n)'"U. E, , , = 110 MeV. Out-of-beam measurements of a-y and e-e-coincidences were performed with the aid of a rotating target mechanism. These measurements have enabled a limited level scheme of the low-spin states in ' ' ?h to be constructed, along with tentative J' assignments and LI hindrance factors. The data are interpreted in terms of thc geometric model assuming a static octupole deformation and compared to that for the N = 133 isotone$ '"Ra and 'IYRn.

Levels inTh223populated byαdecay ofU227

“…In total, ∼50 000 evaporation residues of 227 U were implanted into the PSSD. The cross section for the production of 227 U at the beam energy of 104 MeV was evaluated to be 11 (2) μb.…”

“…Following the α-decay scheme of 227 U published previously [2], the 310-and 247-keV γ transitions populate directly the ground state of 223 Th. The sums of the Q α values of the α transitions populating the 310-and 247-keV levels and the energies of corresponding internal transitions are 7234(4) and 7234(3) keV, respectively.…”

“…While higher-energy levels can be well studied by in-beam methods, lower-energy ones can be well investigated by the α-decay spectroscopy. These different approaches resulted in different levels observed in 223 Th in previous studies [1,2]. In this work we present the results of the measurement aimed at the study of the α decay of 227 U and excited levels in its daughter nucleus 223 Th investigated by the α-γ decay spectroscopic methods.…”

“…Shortly after that experiment, an out-of-beam study of excited levels in 223 Th was performed at the cyclotron facility at Louvain-la-Neuve, Belgium [2]. In that study, the compound nucleus 230 U was synthesized in the reaction 22 Ne + 208 Pb, and 223 Th was produced by the α decay of 227 U (produced in the 3n evaporation channel of the considered reaction).…”

Backbending in the pear-shaped Th90223 nucleus: Evidence of a high-spin octupole to quadrupole shape transition in the actinides

“…We can also notice more recent measurements of low-spin states populated by α decay of 227 U [21,22]. Since the work presented in Ref.…”