EURICA is a project at RIKEN Nishina Center aimed at studying a wide range of exotic nuclei through β-decay measurements and high-resolution γ-ray spectroscopy. The setup is located behind the ...BigRIPS fragment separator and the ZeroDegree spectrometer at the RIBF. EURICA consists of the HPGe cluster detectors from the previous Euroball and RISING projects, together with double-sided silicon-strip detectors for β-decay counting and lifetime measurements. In total, this setup provides us with the possibility to study several aspects of the exotic nuclei produced at the RIBF.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM
Abstract At the FAIR facility, currently under construction at GSI (Darmstadt), a 1.5 AGeV uranium beam with intensities up to 2.5 × 10 11 238 U/spill will impinge on a graphite target at the ...entrance of the Super-FRS for the production of a wide range of rare isotopes by projectile fission and fragmentation. The next generation in-flight magnetic separator Super-FRS, operated up to a magnetic rigidity of 20 Tm with a large angular acceptance (Δ θ = ± 40 mrad, Δ ϕ = ± 20 mrad) and momentum acceptance (Δ p/p = ± 2.5%), requires a new generation of tracking detectors with a position resolution of 0.2 mm ( σ x ) over large detector areas reaching up to 570 cm 2 . Besides gas detectors, planar detectors made of scintillating fibers are an option worth investigating not only because of the comparable material budget but especially for the fast response and high-rate capability. A one-dimensional prototype consisting of 128 fibers with active area of 25.6 × 100 mm 2 coupled to Multi-Pixel-Photon Counters (MPPCs) and readout by FPGA TDC is described together with some recent 197 Au beam test results.
The inverse kinematics technique, applied to radioactive beams and combined to the Coulomb excitation method, is a powerful tool to study low-energy fission. A novel experimental setup was developed ...within the R3B/SOFIA (Reactions with Relativistic Radioactive Beams/Studies On FIssion with Aladin) collaboration to identify in mass and atomic numbers both fission fragments in coincidence. These new data provide elemental, isobaric, and isotonic yields for the fission along the thorium isotopic chain. Results are also compared to previous measurements using either the same reaction mechanism or thermal-neutron induced fission. This latter comparison permits to probe the influence of the excitation energy in the fission process.
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Taking benefit of the R3B/SOFIA setup to measure the mass and the nuclear charge of both fission fragments in coincidence with the total prompt-neutron multiplicity, the scission configurations are ...inferred along the thorium chain, from the asymmetric fission in the heavier isotopes to the symmetric fission in the neutron-deficient thorium. Against all expectations, the symmetric scission in the light thorium isotopes shows a compact configuration, which is in total contrast to what is known in the fission of the heavier thorium isotopes and heavier actinides. This new main symmetric scission mode is characterized by a significant drop in deformation energy of the fission fragments of about 19 MeV, compared to the well-known symmetric scission in the uranium-plutonium region.
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Isomeric states were observed in nuclei produced in an experiment at the RIKEN Nishina Center Radioactive Isotope Beam Factory following the in-flight fission of a 345 MeV/nucleon
238
U beam. Isomers ...reported in nuclei spanning a predicted prolate-oblate shape change boundary,
111
Zr (
E
=
283.1
keV;
τ
=
0.326
(
63
)
μ
s),
112
Nb (
E
=
44.2
keV;
τ
=
0.094
(
26
)
μ
s),
113
Nb (
E
=
135.4
keV;
τ
=
0.846
(
80
)
μ
s), and
115
Mo (
E
=
198.6
keV;
τ
=
63
(
4
)
μ
s), are compared to potential-energy surface calculations which gave a selection of low-lying configurations for each nucleus. Tentative assignments of ground and excited states were made based on energy similarities to the calculations, reduced transition probabilities of the decays, and constraints of transition multipolarities from
γ
-ray coincidence measurements. These assignments are suggestive of significant deformation being persistent for
N
>
70
in this region. In addition, isomers in
108
Nb,
109
Nb,
113
Tc,
117
Ru,
119
Ru,
120
Rh, and
122
Rh, not spanning the prolate-oblate transition discussed, are presented.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Experimental investigations of transactinoide elements provide benchmark results for chemical theory and probe the predictive power of trends in the periodic table. So far, in gas-phase chemical ...reactions, simple inorganic compounds with the transactinoide in its highest oxidation state have been synthesized. Single-atom production rates, short half-lives, and harsh experimental conditions limited the number of experimentally accessible compounds. We applied a gas-phase carbonylation technique previously tested on short-lived molybdenum (Mo) and tungsten (W) isotopes to the preparation of a carbonyl complex of seaborgium, the 106th element. The volatile seaborgium complex showed the same volatility and reactivity with a silicon dioxide surface as those of the hexacarbonyl complexes of the lighter homologs Mo and W. Comparison of the product’s adsorption enthalpy with theoretical predictions and data for the lighter congeners supported a Sg(CO)₆ formulation.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Synopsis We report on performing high resolution recoil ion momentum spectroscopy in a reaction microscope (ReMi) on a target of dipole-force trapped cold 6Li atoms in a non-interacting |1〉-|2〉 spin ...mixture and coincident detection of recoil ions and photoelectrons. Photo-ionization occurs from the electronic ground state of the 6Li atoms and IR photons significantly contribute to the ion yield via 3-photon resonances. High resolution time-of-flight spectra are obtained by modulating the trap depth synced with the arrival of the fs laser pulses.
Synopsis In order to study ultracold gases by photoionization within a Reaction Microscope (ReMi), we investigate a new magneto-optical trap (MOT) configuration for cooling and trapping the atoms. ...Here we present the simulation results. In comparison with the conventional MOT, the new MOT has four laser beam axes. Two radial laser beam axes along x and y directions and two laser beam axes inclined ± 450 to the MOT/Feshbach coil axis (z axis).
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