T. Nakamura
A5009524616- Nuclear Physics and Applications
- Nuclear physics research studies
- Nuclear reactor physics and engineering
- Radiation Therapy and Dosimetry
- Radiation Detection and Scintillator Technologies
- Atomic and Molecular Physics
- Astronomical and nuclear sciences
- Quantum Chromodynamics and Particle Interactions
- Graphite, nuclear technology, radiation studies
- Atomic and Subatomic Physics Research
- Particle accelerators and beam dynamics
- Advanced NMR Techniques and Applications
- Quantum, superfluid, helium dynamics
- Astro and Planetary Science
- Fusion materials and technologies
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Chemical Physics Studies
- Particle physics theoretical and experimental studies
- Boron Compounds in Chemistry
- Nuclear Materials and Properties
- Nuclear and radioactivity studies
- Superconducting Materials and Applications
- Recycling and Waste Management Techniques
- Radiation Effects in Electronics
- Neutrino Physics Research
Tohoku University
2015-2025
Fuji Electric (Japan)
2014-2025
Tokyo Institute of Technology
2015-2024
GSI Helmholtz Centre for Heavy Ion Research
2020-2024
Kōchi University
2018-2024
Institute of Science Tokyo
2024
RIKEN Nishina Center
2009-2023
Université Paris-Saclay
2019-2023
Institut de Recherche sur les Lois Fondamentales de l'Univers
2019-2023
CEA Paris-Saclay
2019-2023
The high-energy particle transport code NMTC/JAM, which has been developed at JAERI, was improved for the heavy ion calculation by incorporating JQMD code, SPAR and Shen formula. new NMTC/JAM named PHITS (Particle Heavy-Ion Transport System) is first general-purpose Monte Carlo over incident energies from several MeV/nucleon to GeV/nucleon.
Many neutron star properties, such as the proton fraction, reflect symmetry energy contributions to equation of state that dominate when and densities differ strongly. To constrain these at suprasaturation densities, we measure spectra charged pions produced by colliding rare isotope tin (Sn) beams with isotopically enriched Sn targets. Using ratios pion measured high transverse momenta, deduce slope be $42<L<117\text{ }\text{ }\mathrm{MeV}$. This value is slightly lower but consistent $L$...
A long-standing question in nuclear physics is whether chargeless systems can exist. To our knowledge, only neutron stars represent near-pure systems, where neutrons are squeezed together by the gravitational force to very high densities. The experimental search for isolated multi-neutron has been an ongoing quest several decades1, with a particular focus on four-neutron system called tetraneutron, resulting few indications of its existence so far2-4, leaving tetraneutron elusive six...
Increases in the low attenuation areas (LAA) of chest x-ray computed tomography images patients with chronic obstructive pulmonary disease (COPD) have been reported to reflect development pathological emphysema. We examined statistical properties LAA clusters COPD and healthy subjects. In patients, percentage lung field occupied by LAAs (LAA%) ranged from 2.6 67.6. contrast, LAA% was always <30% The cumulative size distribution followed a power law characterized an exponent D . show that...
Partial cross sections and corresponding momentum distributions have been studied in the one-neutron knockout reaction ( ${}^{12}\mathrm{Be}{,}^{11}\mathrm{Be}+\ensuremath{\gamma}$) on a ${}^{9}\mathrm{Be}$ target at 78 MeV/nucleon. The resulting spectroscopic factors for only two bound states of ${}^{11}\mathrm{Be}$ are $0.42\ifmmode\pm\else\textpm\fi{}0.06$ $1/{2}^{+}$) $0.37\ifmmode\pm\else\textpm\fi{}0.06$ $1/{2}^{\ensuremath{-}}$), where errors experimental only. This result shows that...
An exclusive measurement has been made of the Coulomb dissociation two-neutron halo nucleus 11Li at 70 MeV/nucleon RIKEN. Strong low-energy (soft) E1 excitation is observed, peaked about Ex = 0.6 MeV with B(E1) 1.42(18) e2fm2 for Erel < or 3 MeV, which was largely missed in previous measurements. This represents strongest transition ever observed such low energies. The spectrum reproduced well by a three-body model strong correlation, further supported non-energy-weighted cluster sum rule.
The extremely neutron-rich nucleus ${}^{19}\mathrm{C}$ has been studied by Coulomb dissociation into ${}^{18}\mathrm{C}+n$ at $67A\mathrm{MeV}$. A large $E1$ strength of $0.71\ifmmode\pm\else\textpm\fi{}0.07{e}^{2}\mathrm{fm}{}^{2}$ observed low excitation energies. An analysis the angular distribution center mass led to a determination neutron separation energy be $530\ifmmode\pm\else\textpm\fi{}130\mathrm{keV}$. can well reproduced for ground state structure with dominant $s$-wave valence...
A search for new isotopes using in-flight fission of a 345 MeV/nucleon 238 U beam has been carried out at the RI Beam Factory RIKEN Nishina Center. Fission fragments were analyzed and identified by superconducting separator BigRIPS. We observed 45 neutron-rich isotopes: 71 Mn, 73,74 Fe, 76 Co, 79 Ni, 81,82 Cu, 84,85 Zn, 87 Ga, 90 Ge, 95 Se, 98 Br, 101 Kr, 103 Rb, 106,107 Sr, 108,109 Y, 111,112 Zr, 114,115 Nb, 115,116,117 Mo, 119,120 Tc, 121,122,123,124 Ru, 123,124,125,126 Rh, 127,128 Pd, 133...
The cross section for Coulomb dissociation of $^{8}\mathrm{B}$---the $^{208}\mathrm{Pb}(^{8}\mathrm{B}^{7}\mathrm{Be}p)^{208}\mathrm{Pb}$ reaction---was measured using a $^{8}\mathrm{B}$ radioactive beam 46.5 MeV/nucleon energy, and the $^{7}\mathrm{Be}(p,\ensuremath{\gamma})^{8}\mathrm{B}$ capture reaction was deduced at low energies; ${E}_{\mathrm{c}.\mathrm{m}.}=0.6\ensuremath{-}1.7$ MeV. extracted astrophysical ${S}_{17}$ factors were found to be consistent with values by Vaughn et al....
Reaction cross sections (sigma(R)) for 19C, 20C and the drip-line nucleus 22C on a liquid hydrogen target have been measured at around 40A MeV by transmission method. A large enhancement of sigma(R) compared to those neighboring C isotopes was observed. Using finite-range Glauber calculation under an optical-limit approximation rms matter radius deduced be 5.4+/-0.9 fm. It does not follow systematic behavior radii in carbon with N < or = 14, suggesting neutron halo. found analysis based...
Breakup reactions of the one-neutron halo nucleus 11Be on Pb and C targets at about 70 MeV/u have been investigated by measuring momentum vectors incident 11Be, outgoing 10Be, neutron in coincidence. The relative energy spectra as well angular distributions 10Be+n center mass extracted for both targets. For breakup target, selection forward scattering angles is found to be effective extract almost purely first-order E1 Coulomb component, exclude nuclear contribution higher-order components....
The cross sections for single-neutron removal from the very neutron-rich nucleus $^{31}\mathrm{Ne}$ on Pb and C targets have been measured at $230\text{ }\text{ }\mathrm{MeV}/\mathrm{\text{nucleon}}$ using RIBF facility RIKEN. deduced large Coulomb breakup section of 540(70) mb is indicative a soft $E1$ excitation. Comparison with direct-breakup model calculations suggests that valence neutron occupies low-$\ensuremath{\ell}$ orbital (most probably $2{p}_{3/2}$) small separation energy...
A search for isomeric \ensuremath{\gamma} decays among fission fragments from 345 MeV/nucleon ${}^{238}$U has been performed at the RIKEN Nishina Center RI Beam Factory. Fission were selected and identified using superconducting in-flight separator BigRIPS implanted in an aluminum stopper. Delayed rays detected three clover-type high-purity germanium detectors located focal plane within a time window of 20 \ensuremath{\mu}s following implantation. We total 54 microsecond isomers with...
The Telescope Array observatory utilizes fluorescence detectors and surface to observe air showers produced by ultra high energy cosmic rays in the Earth's atmosphere. Cosmic ray events observed this way are termed hybrid data. depth of shower maximum is related mass primary particle that generates shower. This paper reports on maxima data collected over 8.5 years using Black Rock Mesa Long Ridge conjunction with array detectors. We compare means standard deviations $X_{\mathrm{max}}$...
Cross sections of 1n-removal reactions from the neutron-rich nucleus Mg37 on C and Pb targets parallel momentum distributions residues target have been measured at 240 MeV/nucleon. A combined analysis these distinct nuclear- Coulomb-dominated reaction data shows that ground state has a small 1n separation energy 0.22−0.09+0.12 MeV an appreciable p-wave neutron single-particle strength. These results confirm lies near edge "island inversion" sizable halo component, heaviest such system...
A search for the heaviest isotopes of fluorine, neon, and sodium was conducted by fragmentation an intense Ca48 beam at 345 MeV/nucleon with a 20-mm-thick beryllium target identification in large-acceptance separator BigRIPS RIKEN Radioactive Isotope Beam Factory. No events were observed F32,33, Ne35,36, Na38 only one event Na39 after extensive running. Comparison predicted yields excludes existence bound states these unobserved high confidence levels. The present work indicates that F31...
The unbound nucleus O26 has been investigated using invariant-mass spectroscopy following one-proton removal reaction from a F27 beam at 201 MeV/nucleon. decay products, O24 and two neutrons, were detected in coincidence the newly commissioned SAMURAI spectrometer RIKEN Radioactive Isotope Beam Factory. ground-state resonance was found to lie only 18±3(stat)±4(syst) keV above threshold. In addition, higher lying level, which is most likely first 2+ state, observed for time 1.28−0.08+0.11 MeV...
The interaction cross sections (σI) of the very neutron-rich carbon isotopes 19C, 20C and 22C have been measured on a target at 307, 280, 235 MeV/nucleon, respectively. A σI 1.280±0.023 b was obtained for 22C, significantly larger than 19,20C, supporting halo character 22C. root-mean-squared matter radius 3.44±0.08 fm deduced using four-body Glauber reaction model. This value is smaller an earlier estimate (of 5.4±0.9 fm) derived from measurement hydrogen 40 MeV/nucleon. These new,...