360 research outputs found
In-beam spectroscopic studies of S nucleus
The structure of the S nucleus has been studied at GANIL through the
one proton knock-out reaction from a Cl secondary beam at 42
AMeV. The rays following the de-excitation of S were
detected in flight using the 70 BaF detectors of the Ch\^{a}teau de
Cristal array. An exhaustive -coincidence analysis allowed an
unambiguous construction of the level scheme up to an excitation energy of 3301
keV. The existence of the spherical 2 state is confirmed and three new
-ray transitions connecting the prolate deformed 2 level were
observed. Comparison of the experimental results to shell model calculations
further supports a prolate and spherical shape coexistence with a large mixing
of states built on the ground state band in S.Comment: 6 pages, 5 figures, accepted for publication in Physical Review
Isomers in Pd128 and Pd126: Evidence for a Robust Shell Closure at the Neutron Magic Number 82 in Exotic Palladium Isotopes
The level structures of the very neutron-rich nuclei Pd128 and Pd126 have been investigated for the first time. In the r-process waiting-point nucleus Pd128, a new isomer with a half-life of 5.8(8) μs is proposed to have a spin and parity of 8+ and is a
First application of mass measurement with the Rare-RI Ring reveals the solar r-process abundance trend at A=122 and A=123
The Rare-RI Ring (R3) is a recently commissioned cyclotron-like storage ring
mass spectrometer dedicated to mass measurements of exotic nuclei far from
stability at Radioactive Isotope Beam Factory (RIBF) in RIKEN. The first
application of mass measurement using the R3 mass spectrometer at RIBF is
reported. Rare isotopes produced at RIBF, Sn, In, Cd,
Ag, Pd, were injected in R3. Masses of In, Cd,
and Pd were measured whereby the mass uncertainty of Pd was
improved. This is the first reported measurement with a new storage ring mass
spectrometery technique realized at a heavy-ion cyclotron and employing
individual injection of the pre-identified rare nuclei. The latter is essential
for the future mass measurements of the rarest isotopes produced at RIBF. The
impact of the new Pd result on the solar -process abundances in a
neutron star merger event is investigated by performing reaction network
calculations of 20 trajectories with varying electron fraction . It is
found that the neutron capture cross section on Pd increases by a
factor of 2.2 and -delayed neutron emission probability,
, of Rh increases by 14\%. The neutron capture cross
section on Pd decreases by a factor of 2.6 leading to pileup of
material at , thus reproducing the trend of the solar -process
abundances. The trend of the two-neutron separation energies (S)
was investigated for the Pd isotopic chain. The new mass measurement with
improved uncertainty excludes large changes of the S value at
. Such large increase of the S values before was
proposed as an alternative to the quenching of the shell gap to
reproduce -process abundances in the mass region of
Spectroscopic factor and proton formation probability for the d3/2 proton emitter 151mLu
The quenching of the experimental spectroscopic factor for proton emission from the short-lived d3/2 isomeric state in 151mLu was a long-standing problem. In the present work, proton emission from this isomer has been reinvestigated in an experiment at the Accelerator Laboratory of the University of Jyväskylä. The proton-decay energy and half-life of this isomer were measured to be 1295(5) keV and 15.4(8) μs, respectively, in agreement with another recent study. These new experimental data can resolve the discrepancy in the spectroscopic factor calculated using the spherical WKB approximation. Using the R-matrix approach it is found that the proton formation probability indicates no significant hindrance for the proton decay of 151mLu
Multiple β− decaying states in 194 Re: Shape evolution in neutron-rich osmium isotopes
β decays from heavy, neutron-rich nuclei with A∼190 have been investigated following their production via the relativistic projectile fragmentation of an E/A=1 GeV 208Pb primary beam on a ∼2.5 g/cm2 9Be target. The reaction products were separated a
Commissioning of the BRIKEN beta-delayed neutron detector for the study of exotic neutron-rich nuclei
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