A5088491496- Nuclear physics research studies
- Nuclear Physics and Applications
- Astronomical and nuclear sciences
- Nuclear reactor physics and engineering
- Atomic and Molecular Physics
- Quantum Chromodynamics and Particle Interactions
- Radioactive Decay and Measurement Techniques
- Radiopharmaceutical Chemistry and Applications
- Distributed and Parallel Computing Systems
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Laser-Plasma Interactions and Diagnostics
- Mass Spectrometry Techniques and Applications
- Laser-induced spectroscopy and plasma
- Particle accelerators and beam dynamics
- Scientific Research and Discoveries
- Radioactivity and Radon Measurements
- Neutrino Physics Research
- Radioactive contamination and transfer
- Gamma-ray bursts and supernovae
- Quantum, superfluid, helium dynamics
- Radiation Detection and Scintillator Technologies
- Laser-Matter Interactions and Applications
- Scientific Computing and Data Management
- Astro and Planetary Science
Japan Atomic Energy Agency
2015-2024
Advanced Science Research Center
2014-2024
Tohoku University
2019
Waseda University
1998-2014
Oak Ridge National Laboratory
2010
University of Tennessee at Knoxville
2010
Colorado College
2010
Argonne National Laboratory
2010
RIKEN Nishina Center
2010
Konan University
2007-2008
The convincing candidate event of the isotope 113th element, 278 113, and its daughter nuclei, 274 111 270 Mt, were observed, for first time, in 209 Bi + 70 Zn reaction at a beam energy 349.0 MeV with total dose 1.7 ×10 19 . Alpha decay energies times candidates, 111, (11.68 ±0.04 MeV, 0.344 ms), (11.15 ±0.07 9.26 (10.03 7.16 respectively. production cross section was deduced to be 55 +150 -45 fb (10 -39 cm 2 ).
A nuclidic mass formula composed of a gross term, an even-odd term and shell is presented as revised version the constructed by present authors published in 2000. The has almost same functional form previous formula, but parameter values it are somewhat different. treated more carefully, considerable improvement realized. exactly one; was obtained using spherical single-particle potentials treating deformed nucleus superposition nuclei. new applicable to nuclei with Z ≥ 2 N 2....
An isotope of the 113th element, i.e., 278 113, was produced in a nuclear reaction with 70 Zn beam on 209 Bi target. We observed six consecutive α-decays following implantation heavy particle nearly same position semiconductor detector under an extremely low background condition. The fifth and sixth decays are fully consistent sequential 262 Db 258 Lr both decay energies times. This indicates that present chain consisted 274 Rg ( Z =111), 270 Mt =109), 266 Bh =107), =105), =103) firm...
RIKEN (The Institute of Physical and Chemical Research), Wako, Saitama 351-0198 Department Physics, University, 338-8570 Center for Instrumental Analysis, Niigata 950-2181 Nuclear Study, University Tokyo, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 Chemistry, Tsukuba, 305-8571 Tohoku Sendai 980-8578 Yamagata 990-8560
The production and decay of 277 112 have been investigated using a gas-filled recoil ion separator in irradiations 208 Pb targets with 70 Zn beam at 349.5 MeV. We observed two α-decay chains that can be assigned to subsequent decays from produced the Pb( Zn,n) reaction. After emitting four consecutive α-particles, both terminate by spontaneous fission 261 Rf, energies times obtained present work agree well those reported group Gesellschaft für Schwerionenforschung (GSI), Germany. result...
Almost fully stripped Fe ions accelerated up to 0.9 GeV are demonstrated with a 200 TW femtosecond high-intensity laser irradiating micron-thick Al foil impurity on the surface. An energetic low-emittance high-density beam of heavy large charge-to-mass ratio can be obtained, which is useful for many applications, such as compact radio isotope source in combination conventional technology.
The masses of ^{246}Es, ^{251}Fm, and the transfermium nuclei ^{249-252}Md ^{254}No, produced by hot- cold-fusion reactions, in vicinity deformed N=152 neutron shell closure, have been directly measured using a multireflection time-of-flight mass spectrograph. ^{246}Es ^{249,250,252}Md were for first time. Using ^{249,250}Md as anchor points α decay chains, heavier nuclei, up to ^{261}Bh ^{266}Mt, determined. These new compared with theoretical global models demonstrated be good agreement...
Recent developments in precision mass spectrometry of radioactive isotopes (RI) and some selected related physics subjects are reviewed. In the last decades, besides conventional technologies RI beam experiments, short-lived nuclei has significantly boosted its performance terms sensitivity precision. Whereas single-path measurements still employed for studies most rarely produced nuclides, though at a moderate level, modern methods based on storage freshly exotic period time. One biggest...
Using a mulit-reflection time-of-flight mass spectrograph (MRTOF-MS) located after gas cell coupled with the gas-filled recoil ion separator GARIS-II, masses of several heavy nuclei have been directly and precisely measured. The were produced via fusion-evaporation reactions separated from projectile-like target-like particles using GARIS-II before being stopped in helium-filled cell. Time-of-flight spectra for three isobar chains, 205Fr-205Rn-205At-205Po, 206Fr-206Rn-206At...
The atomic masses of ^{55}Sc, ^{56,58}Ti, and ^{56-59}V have been determined using the high-precision multireflection time-of-flight technique. radioisotopes produced at RIKEN's Radioactive Isotope Beam Factory (RIBF) delivered to novel designed gas cell system, which has recently commissioned downstream ZeroDegree spectrometer following BigRIPS separator. For ^{56,58}Ti ^{56-59}V, mass uncertainties reduced down order 10 keV, shedding new light on N=34 shell effect in Ti V isotopes by first...
The production and decay of 272 111 has been investigated using a gas-filled recoil ion separator in irradiations 209 Bi targets with 64 Ni beam at 320, 323 326 MeV. We have observed 14 α-decay chains total, that can be assigned, on the basis their time correlations, to subsequent decays from produced Bi( Ni,1n) reaction. present result is first clear confirmation for discovery its products, 264 Bh 268 Mt, reported previously by GSI group. New information half-lives energies as well...
A new parametrization for the phenomenological nuclear level density taking account of shell and pairing energies recent mass formula Koura, Tachibana, Uno, Yamada (KTUY05) a is proposed. Such often required to calculate reaction cross sections nuclei off-stability, especially fission systems astrophysical applications. With Gilbert-Cameron with energy dependent parameter Ignatyuk, smooth dependence asymptotic a* on number obtained. At low energies, systematics constant temperature model are...
Decay properties of an isotope 266 Bh and its daughter nucleus 262 Db produced by the 248 Cm( 23 Na,5 n ) reaction were studied using a gas-filled recoil separator coupled with position-sensitive semiconductor detector. was clearly identified from correlation known nuclide, Db. The obtained decay are consistent those observed in 278 113 chain, which provided further confirmation discovery 113.
A phenomenological formula is presented for the partial half-life from Q value α decay. It constructed in a conventional way by considering penetrability of charged particle spherical Coulomb potential. Parameters are fixed because they determined physical constants except following three adjustable parameters: product collision frequency an and formation probability, N; distance between charge radius inner point barrier, r 0; odd-mass hindrance, h 0. The values obtained parameters...
We present the first direct measurement of atomic mass a superheavy nuclide. Atoms $^{257}$Db ($Z$=105) were produced online at RIKEN Nishina Center for Accelerator-Based Science using fusion-evaporation reaction $^{208}$Pb($^{51}$V, 2n)$^{257}$Db. The gas-filled recoil ion separator GARIS-II was used to suppress both unreacted primary beam and some transfer products, prior delivering energetic ions helium stopping cell wherein they thermalized. Thermalized $^{257}$Db$^{3+}$ then transferred...
The masses of the exotic isotopes $^{210\ensuremath{-}214}\mathrm{Ac}$ and $^{210\ensuremath{-}214}\mathrm{Ra}$ have been measured with a multireflection time-of-flight mass spectrograph. These were obtained in flight as fusion-evaporation products behind gas-filled recoil ion separator GARIS-II at RIKEN. new direct measurements serve an independent benchmark for existing $\ensuremath{\alpha}\text{\ensuremath{-}}\ensuremath{\gamma}$ spectroscopy data this region. Further, anchor points are...
The direct and semi-direct (DSD) components of the neutron capture cross sections are calculated for a series tin isotopes by employing single-particle potential (SPP) that gives good reproduction known energies (SPEs) over wide mass region. results compared with Hauser-Feshbach (HF) contribution in energy region astrophysical interest. result shows HF component drops off rapidly isotope $^{132}\mathrm{Sn}$ toward more neutron-rich ones, whereas DSD decreases only smoothly eventually becomes...
We investigate how the neutron drip line is related to density dependence of symmetry energy by using a macroscopic nuclear model that allows us calculate masses in way dependent on equation state asymmetric matter. The obtained from these shown appreciably shift neutron-rich side chart as derivative increases. Such clearly seen for light nuclei, feature coming mainly surface property nuclei.
An improvement to the single-particle structure is made gross theory, which a global $\ensuremath{\beta}$-decay model. The theory based on sum rule of intensity transition and strength function. This model provides reasonable results for rates delayed neutrons entire nuclear mass region. attempt improve $\ensuremath{\beta}$ decay by considering change in parity at level ground-state nuclei. In this treatment, matrix elements are suppressed when single neutron proton levels different allowed...