0000000000124582
AUTHOR
Naohito Inabe
New neutron-deficient isotopes from $^{78}$Kr fragmentation
In an experiment with the BigRIPS separator at the RIKEN Nishina Center, the fragmentation of a $^{78}$Kr beam allowed the observation of new neutron-deficient isotopes at the proton drip-line. Clean identification spectra could be produced and $^{63}$Se, $^{67}$Kr, and $^{68}$Kr were identified for the first time. In addition, $^{59}$Ge was also observed. Three of these isotopes, $^{59}$Ge, $^{63}$Se, and $^{67}$Kr, are potential candidates for ground-state two-proton radioactivity. In addition, the isotopes $^{58}$Ge, $^{62}$Se, and $^{66}$Kr were also sought but without success. The present experiment also allowed the determination of production cross sections for some of the most exotic…
Studying the Exotic Decay $^{70}Kr$ $\rightarrow$ $^{70}Br$
Acta physica Polonica / B 51(3), 587 (2020). doi:10.5506/APhysPolB.51.587
Beta decay and isomer spectroscopy in the 132Sn region: New results from EURICA
A. Jungclaus et al.; XX International School on Nuclear Physics, Neutron Physics and Applications (Varna2013); Open Access. 4 pags.; 1 fig.
βdecay of semi-magicCd130: Revision and extension of the level scheme ofIn130
This work was supported by the Spanish Ministerio de Ciencia e Innovacion under contract FPA2011-29854-C04 and the Spanish Ministerio de Economia y Competitividad under Contract No. FPA2014-57196-C5- 4-P, the Generalitat Valenciana (Spain) under Grant No. PROMETEO/2010/101, the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (NRF-2014S1A2A2028636, 2016K1A3A7A09005579), the Priority Centers Research Program in Korea (2009-0093817), OTKA Contract No. K-100835, JSPS KAKENHI (Grant No. 25247045), the European Commission through the Marie Curie Actions call FP7-PEOPLE-2011-IEF under Contract No. 300096, the US Department of Energy, Office of Nuclear Physic…
Nuclear structure of Te isotopes beyond neutron magic number N=82
15 pags., 10 figs., 4 tabs.
Shape evolution in116,118Ru: Triaxiality and transition between the O(6) and U(5) dynamical symmetries
${}^{116}\mathrm{Ru}$ and ${}^{118}\mathrm{Ru}$ have been studied via $\ensuremath{\beta}$-delayed $\ensuremath{\gamma}$-ray spectroscopy of nuclei produced in fragmentation reactions at the Radioactive Ion-Beam Factory (RIBF) facility. Level schemes with positive-parity states up to spin $J=6$ have been constructed. The results have been discussed in terms of the interacting boson model, the algebraic collective model, and total Routhian surfaces. We conclude that the very neutron-rich nuclei still show many features associated with triaxial $\ensuremath{\gamma}$-soft nuclei, represented by the O(6) symmetry, but are approaching a spherical structure, the U(5) symmetry, with increasing neu…
Determination of beta-delayed neutron emission probability limits of rhodium isotopes by gamma-ray spectroscopy
9 pags., 5 figs., 5 tabs. -- 27th International Nuclear Physics Conference (INPC2019) 29 July - 2 August 2019, Glasgow, UK
Proton Shell Evolution below Sn132 : First Measurement of Low-Lying β -Emitting Isomers in Ag123,125
The β-delayed γ-ray spectroscopy of neutron-rich 123;125Ag isotopes is investigated at the Radioactive Isotope Beam Factory of RIKEN and the long-predicted 1/2¯ β-emitting isomers in 123;125Ag are identified for the first time. With the new experimental results, the systematic trend of energy spacing between the lowest 9/2+ and 1/2¯ levels is extended in Ag isotopes up to N = 78, providing a clear signal for the reduction of the Z = 40 subshell gap in Ag towards N = 82. Shellmodel calculations with the state-of-the-art VMU plus M3Y spin-orbit interaction give a satisfactory description of the low-lying states in 123;125Ag. The tensor force is found to play a crucial role in the evolution of…
Two-Proton Radioactivity ofKr67
In an experiment with the BigRIPS separator at the RIKEN Nishina Center, we observed two-proton (2p) emission from 67Kr. At the same time, no evidence for 2p emission of 59Ge and 63Se, two other potential candidates for this exotic radioactivity, could be observed. This observation is in line with Q value predictions which pointed to 67Kr as being the best new candidate among the three for two-proton radioactivity. 67Kr is only the fourth 2p ground-state emitter to be observed with a half-life of the order of a few milliseconds. The decay energy was determined to be 1690(17) keV, the 2p emission branching ratio is 37(14)%, and the half-life of 67Kr is 7.4(30) ms.
β decay of the very neutron-deficient Ge60 and Ge62 nuclei
We report here the results of a study of the $\beta$ decay of the proton-rich Ge isotopes, $^{60}$Ge and $^{62}$Ge, produced in an experiment at the RIKEN Nishina Center. We have improved our knowledge of the half-lives of $^{62}$Ge (73.5(1) ms), $^{60}$Ge (25.0(3) ms) and its daughter nucleus, $^{60}$Ga (69.4(2) ms). We measured individual $\beta$-delayed proton and $\gamma$ emissions and their related branching ratios. Decay schemes and absolute Fermi and Gamow-Teller transition strengths have been determined. The mass excesses of the nuclei under study have been deduced. A total $\beta$-delayed proton-emission branching ratio of 67(3)% has been obtained for $^{60}$Ge. New information has…
First observation ofγrays emitted from excited states south-east ofSn132: Theπg9/2−1⊗νf7/2multiplet ofIn83132
For the first time, the γ decay of excited states has been observed in a nucleus situated in the quadrant south-east of doubly magic Sn132, a region in which experimental information so far is limited to ground-state properties. Six γ rays with energies of 50, 86, 103, 227, 357, and 602 keV were observed following the β-delayed neutron emission from Cd85133, populated in the projectile fission of a U238 beam at the Radioactive Isotope Beam Factory at RIKEN within the EURICA project. The new experimental information is compared to the results of a modern realistic shell-model calculation, the first one in this region very far from stability, focusing in particular on the π0g9/2-1 - ν1f7/2 pa…
Observation of a $\gamma$-decaying millisecond isomeric state in $^{128}$Cd$_{80}$
A. Jungclaus et al. -- 6 pags., 5 figs., 2 tabs. -- Open Access funded by Creative Commons Atribution Licence 4.0
New isomers in $^{125}$Pd$_{79}$ and $^{127}$Pd$_{81}$: Competing proton and neutron excitations in neutron-rich palladium nuclides towards the $N = 82$ shell closure
The neutron-rich isotopes of palladium have attracted considerable interest in terms of the evolution of the N=82 neutron shell closure and its influence on the r-process nucleosynthesis. In this Letter, we present the first spectroscopic information on the excited states in Pd and Pd studied using the EURICA γ-ray spectrometer, following production via in-flight fission of a high-intensity U beam at the RIBF facility. New isomeric states with half-lives of 144(4) ns and 39(6) μs have been assigned spins and parities of (23/2 ) and (19/2 ) in Pd and Pd, respectively. The observed level properties are compared to a shell-model calculation, suggesting the competition between proton excitation…
Isomer and beta decay spectroscopy in the132Sn region with EURICA
A. Jungclaus et al.; 4 págs.; 1 fig.; Open Access funded by Creative Commons Atribution Licence 2.0
Evolution of proton single-particle states in neutron-rich Sb isotopes beyond N=82
11 pags., 8 figs., 2 tabs.
Impact of shell evolution on Gamow-Teller β decay from a high-spin long-lived isomer in 127Ag
6 pags., 4 figs., 2 tabs.