Fine structure in the α decay of202Rn

Abstract

The e decay of mass-separated 2~ is studied at the ISOLDE separator. Time sequential a-singles spectra together with e-X-t and e-e-t coincidence events are collected. Fine structure in the e decay is observed and feeding of a low-lying 02 state at 816 keV in 198po is evidenced. This 0 + state can be interpreted as the bandhead of an intruder-state based deformed band, coexisting with the spherical groundstate band. Mixing between normal and intruder states is discussed. A preliminary a-decay study of 2~176 did not yet reveal any fine structure.

Nuclear shape coexistence in Po isotopes: An interacting boson model study

“…This particular part of the mass region has also been analyzed using α-and β-decay studies of mass-separated Rn and At nuclei, resulting in information about excited 0 + states in the isotopes with A = 196-202 [92] and in energy spectra of the isotopes A = 200, 202 [93], as well as making use of α-decay studies from the Rn nuclei for A = 198 [94]. α-decay studies, moving from the Po nuclei into the Pb nuclei, have been a major fingerprint, in particular, in view of the shape coexisting structure in the daughter Pb nuclei.…”

Fine structure in the alpha decay of even-even nuclei as an experimental proof for the stability of theZ=82 magic shell at the very neutron-deficient side

“…We report in this Letter on an experimental study of the a decay to excited 0+ states in ' Po, 190,192, 194pb I [18], and ' ' Pt [19] and to the study of the a feeding towards the first excited 0+ and/or 2+ states in ' Po ' ' ' Pb, ' ' ' "Hg, Pt, and ' ' ' Qs More details on the experimental procedure can be found in Refs. [16][17][18][19]. Table I summarizes the experimental results.…”

“…Figure 1 gives an overview of the fine structure in the a decay of these nuclei, only the a decay to the first excited 0+ and 2+ states is given. [16][17][18][19]. The excited 0 states that have been identified by the a-decay study are given in italic characters.…”

“…Although these shell-model intruder states come down to low energies in the polonium, lead, and mercury isotopes (in ' ' ' 4Pb and ' Hg they even become the first excited state), their mixing with the normal states is limited. In ' Po, the first excited 0+ state is less than 6% mixed with the ground state configuration [16,20]. Using lifetime measurements of the EO transition to the ground state [17], the mixing in the lead nuclei of normal with intruder states is deduced to be 0.3% in Pb, 0.5% in Pb, and & 2% in Pb.…”

Systematics of the α decay to vibrational2+states

“…In the last decade, this new kind of α-decay spectroscopy was mainly used to investigate 0 + and 2 + excited states in the Pb region by the ISOLDE collaboration [14][15][16][17][18][19][20] and more recently by the Liverpool-Jyväskylä-Helsinki collaboration [21]. There is also an increasing interest in α-decay experiments searching for fine structure in the U region [22].…”