How different is the core of F from O ?

Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri. A.*; Hwang, S. H.*; et al.

Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05

https://doi.org/10.1103/PhysRevLett.124.212502

The structure of a neutron-rich F nucleus is investigated by a quasifree () knockout reaction. The sum of spectroscopic factors of orbital is found to be 1.0 0.3. The result shows that the O core of F nucleus significantly differs from a free O nucleus, and the core consists of 35% O, and 65% excited O. The result shows that the O core of F nucleus significantly differs from a free O nucleus. The result may infer that the addition of the proton considerably changes the neutron structure in F from that in O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

Conceptual study on parasitic low-energy RI beam production with in-flight separator BigRIPS and the first stopping examination for high-energy RI beams in the parasitic gas cell

Sonoda, Tetsu*; Katayama, Ichiro*; Wada, Michiharu*; Iimura, Hideki; Sonnenschein, V.*; Iimura, Shun*; Takamine, Aiko*; Rosenbusch, M.*; Kojima, Takao*; Ahn, D. S.*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2019(11), p.113D02_1 - 113D02_12, 2019/11

https://doi.org/10.1093/ptep/ptz120

An in-flight separator, BigRIPS, at RIBF in RIKEN provides each experiment with specific nuclides separated from many nuclides produced by projectile fragmentation or in-flight fission. In this process, nuclides other than separated ones are discarded on the slits in BigRIPS, although they include many nuclides interested from the view point of nuclear structure. In order to extract these nuclides for parasitic experiments, we are developing a method using laser ion-source (PALIS). A test experiment with Se beam from RIBF has been performed by using a gas cell set in BigRIPS. Unstable nuclides around Se were stopped in the gas cell in accordance with a calculation using LISE code. The stopping efficiency has been estimated to be about 30%. As a next step, we will establish the technique for extracting reaction products from the gas cell.

Enhancement of element production by incomplete fusion reaction with weakly bound deuteron

Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.

Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07

https://doi.org/10.1038/s42005-019-0165-1

Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.

Evaluation of deformation and fracture behavior of reinforced concrete using neutron beam technique

Ueno, Kazuki*; Suzuki, Hiroshi; Koyama, Taku*; Nishio, Yuhei*; Kanematsu, Manabu*

Konkurito Kozobutsu No Hoshu, Hokyo, Appuguredo Rombun Hokokushu (CD-ROM), 18, p.647 - 650, 2018/10

no abstracts in English

Novel bond stress evaluation technique using neutron diffraction

Suzuki, Hiroshi; Kusunoki, Koichi*; Kanematsu, Manabu*; Mukai, Tomohisa*

Konkurito Kozobutsu No Hihakai Kensa Shimpojiumu Hobunshu, 6, p.343 - 348, 2018/08

no abstracts in English

Determination approach of dislocation density and crystallite size using a convolutional multiple whole profile software

Murasawa, Kodai*; Takamura, Masato*; Kumagai, Masayoshi*; Ikeda, Yoshimasa*; Suzuki, Hiroshi; Otake, Yoshie*; Hama, Takayuki*; Suzuki, Shinsuke*

Materials Transactions, 59(7), p.1135 - 1141, 2018/07

https://doi.org/10.2320/matertrans.M2017380

Deformation analysis of reinforced concrete using neutron imaging technique

Koyama, Taku*; Ueno, Kazuki*; Sekine, Mariko*; Matsumoto, Yoshihiro*; Kai, Tetsuya; Shinohara, Takenao; Iikura, Hiroshi; Suzuki, Hiroshi; Kanematsu, Manabu*

Materials Research Proceedings, Vol.4, p.155 - 160, 2018/05

https://doi.org/10.21741/9781945291678-24

Non-destructive bond stress evaluation of bending and shear deformed reinforced concrete structure using neutron diffraction

Suzuki, Hiroshi; Kusunoki, Koichi*; Satake, Kosuke*; Kanematsu, Manabu*; Koyama, Taku*; Niwa, Akinobu*; Kabayama, Kenji*; Mukai, Tomohisa*; Kawasaki, Takuro; Harjo, S.

Hihakai Kensa, 67(4), p.180 - 186, 2018/04

https://doi.org/10.11396/jjsndi.67.180

The bond behavior between rebar and concrete under bending moment was investigated by measuring the stress distribution in the two-dimensionally distributed rebars embedded in the reinforced concrete (RC) beam using neutron diffraction. The stress distributions in both of the main rebar and the transverse stirrups embedded in concrete were successfully measured at the fixed measurement configuration without any sample rotations, by suggesting a simple measurement technique on the premise that the transverse restriction from the surrounding concrete to the main rebar is negligible. The bending and shear fracture behavior of the RC beam specimen was predicted by comparing changes in the stress distribution in the rebars measured by neutron diffraction with respect to the applied stress, with the macroscopic deformation measured by strain gauges fixed on the concrete surface. In this study, it was found that the neutron diffraction technique can be a useful technique to evaluate not only the anchorage performance but also the bending behavior of the RC beam.

Development of on-site measurement technique of retained austenite volume fraction by compact neutron source RANS

Ikeda, Yoshimasa*; Takamura, Masato*; Hakoyama, Tomoyuki*; Otake, Yoshie*; Kumagai, Masayoshi*; Suzuki, Hiroshi

Tetsu To Hagane, 104(3), p.138 - 144, 2018/03

https://doi.org/10.2355/tetsutohagane.TETSU-2017-080

Neutron engineering diffraction is a powerful technique which provides the information of the micro structure of steels in bulk-average, while X-ray diffraction or Electron backscatter diffraction can provide information only from the surface layer. However, such measurement using neutron diffraction is typically performed in a large facility such as a reactor and a synchrotron, while a compact neutron source has never been used for this purpose. Authors have recently developed a neutron diffractometer installed in Riken Accelerator driven compact Neutron Source (RANS) and succeeded in the measurement of texture evolution of a steel sheet. In this study, we made an attempt to measure the volume fraction of retained austenite by RANS. Background noise was carefully eliminated in order to detect as many diffraction peaks as possible with low flux neutrons. The volume fraction was estimated by Rietveld analysis. The accuracy of the measurement result was discussed by comparing with those obtained by a large neutron facility (J-PARC TAKUMI). The volume fraction obtained by RANS with reasonable measurement time, i.e. 30 to 300 min, showed only 1 to 2 % discrepancies with those obtained in J-PARC. These comparisons suggest that neutron diffraction by RANS is capable of quantitative analysis of the volume fraction of crystal phases, showing the possibility of practical use of an in-house compact neutron source in the industry.

Pair distribution function analysis of nanostructural deformation of calcium silicate hydrate under compressive stress

Bae, S.*; Jee, H.*; Kanematsu, Manabu*; Shiro, Ayumi*; Machida, Akihiko*; Watanuki, Tetsu*; Shobu, Takahisa; Suzuki, Hiroshi

Journal of the American Ceramic Society, 101(1), p.408 - 418, 2018/01

https://doi.org/10.1111/jace.15185

Despite enormous interest in calcium silicate hydrate (C-S-H), its detailed atomic structure and intrinsic deformation under an external load are lacking. This study demonstrates the nanostructural deformation process of C-S-H in tricalcium silicate (CS) paste as a function of applied stress by interpreting atomic pair distribution function (PDF) based on in situ X-ray scattering. Three different strains in CS paste under compression were compared using a strain gauge and the real and reciprocal space PDFs. PDF refinement revealed that the C-S-H phase mostly contributed to PDF from 0 to 20 whereas crystalline phases dominated that beyond 20. The short-range atomic strains exhibited two regions for C-S-H: I) plastic deformation (0-10 MPa) and II) linear elastic deformation (10 MPa), whereas the long-range deformation beyond 20 was similar to that of Ca(OH). Below 10 MPa, the short-range strain was caused by the densification of C-S-H induced by the removal of interlayer or gel-pore water. The strain is likely to be recovered when the removed water returns to C-S-H.