학술논문
Spectroscopy along Flerovium Decay Chains: Discovery of Ds280 and an Excited State in Cn282
Document Type
article
Author
Såmark-Roth, A; Cox, DM; Rudolph, D; Sarmiento, LG; Carlsson, BG; Egido, JL; Golubev, P; Heery, J; Yakushev, A; Åberg, S; Albers, HM; Albertsson, M; Block, M; Brand, H; Calverley, T; Cantemir, R; Clark, RM; Düllmann, Ch E; Eberth, J; Fahlander, C; Forsberg, U; Gates, JM; Giacoppo, F; Götz, M; Götz, S; Herzberg, R-D; Hrabar, Y; Jäger, E; Judson, D; Khuyagbaatar, J; Kindler, B; Kojouharov, I; Kratz, JV; Krier, J; Kurz, N; Lens, L; Ljungberg, J; Lommel, B; Louko, J; Meyer, C-C; Mistry, A; Mokry, C; Papadakis, P; Parr, E; Pore, JL; Ragnarsson, I; Runke, J; Schädel, M; Schaffner, H; Schausten, B; Shaughnessy, DA; Thörle-Pospiech, P; Trautmann, N; Uusitalo, J
Source
Physical Review Letters. 126(3)
Subject
Language
Abstract
A nuclear spectroscopy experiment was conducted to study α-decay chains stemming from isotopes of flerovium (element Z=114). An upgraded TASISpec decay station was placed behind the gas-filled separator TASCA at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany. The fusion-evaporation reactions ^{48}Ca+^{242}Pu and ^{48}Ca+^{244}Pu provided a total of 32 flerovium-candidate decay chains, of which two and eleven were firmly assigned to ^{286}Fl and ^{288}Fl, respectively. A prompt coincidence between a 9.60(1)-MeV α particle event and a 0.36(1)-MeV conversion electron marked the first observation of an excited state in an even-even isotope of the heaviest man-made elements, namely ^{282}Cn. Spectroscopy of ^{288}Fl decay chains fixed Q_{α}=10.06(1) MeV. In one case, a Q_{α}=9.46(1)-MeV decay from ^{284}Cn into ^{280}Ds was observed, with ^{280}Ds fissioning after only 518 μs. The impact of these findings, aggregated with existing data on decay chains of ^{286,288}Fl, on the size of an anticipated shell gap at proton number Z=114 is discussed in light of predictions from two beyond-mean-field calculations, which take into account triaxial deformation.