Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Park, P.*; Cho, W.*; Kim, C.*; An, Y.*; Kang, Y.-G.*; Avdeev, M.*; Sibille, R.*; Iida, Kazuki*; Kajimoto, Ryoichi; Lee, K. H.*; et al.
Nature Communications (Internet), 14, p.8346_1 - 8346_9, 2023/12
Times Cited Count:0 Percentile:0(Multidisciplinary Sciences)Chiu, I.-H. ; Terada, Kentaro*; Osawa, Takahito; Park, C.*; Takeshita, Soshi*; Miyake, Yasuhiro*; Ninomiya, Kazuhiko*
Meteoritics & Planetary Science, 58(9), p.1333 - 1344, 2023/09
Times Cited Count:0 Percentile:0.01(Geochemistry & Geophysics)Chen, S.*; Browne, F.*; Doornenbal, P.*; Lee, J.*; Obertelli, A.*; Tsunoda, Yusuke*; Otsuka, Takaharu*; Chazono, Yoshiki*; Hagen, G.*; Holt, J. D.*; et al.
Physics Letters B, 843, p.138025_1 - 138025_7, 2023/08
Times Cited Count:1 Percentile:0.02(Astronomy & Astrophysics)Gamma decays were observed in Ca and Ca following quasi-free one-proton knockout reactions from Sc. For Ca, a ray transition was measured to be 1456(12) keV, while for Ca an indication for a transition was observed at 1115(34) keV. Both transitions were tentatively assigned as the decays. A shell-model calculation in a wide model space with a marginally modified effective nucleon-nucleon interaction depicts excellent agreement with experiment for level energies, two-neutron separation energies, and reaction cross sections, corroborating the formation of a new nuclear shell above the N = 34 shell. Its constituents, the and orbitals, are almost degenerate. This degeneracy precludes the possibility for a doubly magic Ca and potentially drives the dripline of Ca isotopes to Ca or even beyond.
Pohl, T.*; Sun, Y. L.*; Obertelli, A.*; Lee, J.*; Gmez-Ramos, M.*; Ogata, Kazuyuki*; Yoshida, Kazuki; Cai, B. S.*; Yuan, C. X.*; Brown, B. A.*; et al.
Physical Review Letters, 130(17), p.172501_1 - 172501_8, 2023/04
Times Cited Count:5 Percentile:92.42(Physics, Multidisciplinary)We report on the first proton-induced single proton- and neutron-removal reactions from the neutron deficient O nucleus with large Fermi-surface asymmetry at 100 MeV/nucleon. Our results provide the first quantitative contributions of multiple reaction mechanisms including the quasifree knockout, inelastic scattering, and nucleon transfer processes. It is shown that the inelastic scattering and nucleon transfer, usually neglected at such energy regime, contribute about 50% and 30% to the loosely bound proton and deeply bound neutron removal, respectively.
Chiu, I.-H. ; Terada, Kentaro*; Osawa, Takahito; Park, C.*; Takeshita, Soshi*; Miyake, Yasuhiro*; Ninomiya, Kazuhiko*
Journal of Physics; Conference Series, 2462, p.012004_1 - 012004_6, 2023/03
Times Cited Count:0 Percentile:0.2(Physics, Applied)In the last decade, non-destructive elemental analysis using negative muon beams advanced significantly. This method can be used to determine the elemental composition of bulk materials without causing damage. In this study, we performed a negative muon irradiation experiment for a Northwest Africa 482 lunar meteorite (NWA482), which was installed in a stainless steel analysis chamber. The analysis chamber was filled with helium gas to suppress the background signals caused by air-scattering muons. The muonic X-rays from Al, Fe, Ca, Mg, Si, and O in the samples were detected using six high-purity germanium semiconductor detectors arranged around the analysis chamber. To correct the X-ray self-absorption effect of the samples, a Monte-Carlo simulation using Geant4 toolkit was used. Based on the quantitative analysis for muonic X-ray measurement with the correction application from the simulation, we successfully investigated the analytical sensitivity of each element in meteorites based on the NWA482 data.
Elekes, Z.*; Juhsz, M. M.*; Sohler, D.*; Sieja, K.*; Yoshida, Kazuki; Ogata, Kazuyuki*; Doornenbal, P.*; Obertelli, A.*; Achouri, N. L.*; Baba, Hidetada*; et al.
Physical Review C, 106(6), p.064321_1 - 064321_10, 2022/12
Times Cited Count:2 Percentile:0.02(Physics, Nuclear)The low-lying level structure of V and V was investigated for the first time. The neutron knockout reaction and inelastic proton scattering were applied for V while the neutron knock-out reaction provided the data for V. Four and five new transitions were determined for V and V, respectively. Based on the comparison to our shell-model calculations using the Lenzi-Nowacki-Poves-Sieja (LNPS) interaction, three of the observed rays for each isotope could be placed in the level scheme and assigned to the decay of the first 11/2 and 9/2 levels. The (,) excitation cross sections for V were analyzed by the coupled-channels formalism assuming quadrupole plus hexadecapole deformations. Due to the role of the hexadecapole deformation, V could not be unambiguously placed on the island of inversion.
Enciu, M.*; Liu, H. N.*; Obertelli, A.*; Doornenbal, P.*; Nowacki, F.*; Ogata, Kazuyuki*; Poves, A.*; Yoshida, Kazuki; Achouri, N. L.*; Baba, Hidetada*; et al.
Physical Review Letters, 129(26), p.262501_1 - 262501_7, 2022/12
Times Cited Count:4 Percentile:46.35(Physics, Multidisciplinary)The one-neutron knockout from Ca was performed at 230 MeV/nucleon combined with prompt spectroscopy. The momentum distributions corresponding to the removal of and neutrons were measured. The cross sections are consistent with a shell closure at the neutron number , found as strong as at and in Ca isotopes from the same observables. The analysis of the momentum distributions leads to a difference of the root-mean-square radii of the neutron and orbitals of 0.61(23) fm, in agreement with the modified-shell-model prediction of 0.7 fm suggesting that the large root-mean-square radius of the orbital in neutron-rich Ca isotopes is responsible for the unexpected linear increase of the charge radius with the neutron number.
Koiwai, Takuma*; Wimmer, K.*; Doornenbal, P.*; Obertelli, A.*; Barbieri, C.*; Duguet, T.*; Holt, J. D.*; Miyagi, Takayuki*; Navrtil, P.*; Ogata, Kazuyuki*; et al.
Physics Letters B, 827, p.136953_1 - 136953_7, 2022/04
Times Cited Count:4 Percentile:52.69(Astronomy & Astrophysics)no abstracts in English
Linh, B. D.*; Corsi, A.*; Gillibert, A.*; Obertelli, A.*; Doornenbal, P.*; Barbieri, C.*; Chen, S.*; Chung, L. X.*; Duguet, T.*; Gmez-Ramos, M.*; et al.
Physical Review C, 104(4), p.044331_1 - 044331_16, 2021/10
Times Cited Count:5 Percentile:46.8(Physics, Nuclear)no abstracts in English
Browne, F.*; Chen, S.*; Doornenbal, P.*; Obertelli, A.*; Ogata, Kazuyuki*; Utsuno, Yutaka; Yoshida, Kazuki; Achouri, N. L.*; Baba, Hidetada*; Calvet, D.*; et al.
Physical Review Letters, 126(25), p.252501_1 - 252501_7, 2021/06
Times Cited Count:10 Percentile:69.3(Physics, Multidisciplinary)Direct proton-knockout reactions of Sc were studied at the RIKEN Radioactive Isotope Beam Factory. Populated states of Ca were investigated through -ray and invariant-mass spectroscopy. Level energies were calculated from the nuclear shell model employing a phenomenological inter-nucleon interaction. Theoretical cross sections to states were calculated from distorted-wave impulse approximation estimates multiplied by the shell model spectroscopic factors. Despite the calculations showing a significant amplitude of excited neutron configurations in the ground-state of Sc, valence proton removals populated predominantly the ground-state of Ca. This counter-intuitive result is attributed to pairing effects leading to a dominance of the ground-state spectroscopic factor. Owing to the ubiquity of the pairing interaction, this argument should be generally applicable to direct knockout reactions from odd-even to even-even nuclei.
Juhsz, M. M.*; Elekes, Z.*; Sohler, D.*; Utsuno, Yutaka; Yoshida, Kazuki; Otsuka, Takaharu*; Ogata, Kazuyuki*; Doornenbal, P.*; Obertelli, A.*; Baba, Hidetada*; et al.
Physics Letters B, 814, p.136108_1 - 136108_8, 2021/03
Times Cited Count:5 Percentile:46.8(Astronomy & Astrophysics)The nuclear structure of Ar was studied by the (,2) reaction using -ray spectroscopy for the bound and unbound states. Comparing the results to our shell-model calculations, two bound and six unbound states were established. The low cross sections populating the two bound states of Ar could be interpreted as a clear signature for the presence of significant sub-shell closures at neutron numbers 32 and 34 in argon isotopes.
Corts, M. L.*; Rodriguez, W.*; Doornenbal, P.*; Obertelli, A.*; Holt, J. D.*; Menndez, J.*; Ogata, Kazuyuki*; Schwenk, A.*; Shimizu, Noritaka*; Simonis, J.*; et al.
Physical Review C, 102(6), p.064320_1 - 064320_9, 2020/12
Times Cited Count:11 Percentile:73.66(Physics, Nuclear)Low-lying excited states in the = 32 isotope Ar were investigated by in-beam -ray spectroscopy following proton- and neutron-knockout, multinucleon removal, and proton inelastic scattering at the RIKEN Radioactive Isotope Beam Factory. The energies of the two previously reported transitions have been confirmed, and five additional states are presented for the first time, including a candidate for a 3 state. The level scheme built using coincidences was compared to shell-model calculations in the model space and to predictions based on chiral two- and three-nucleon interactions. Theoretical proton- and neutron-knockout cross sections suggest that two of the new transitions correspond to 2 states, while the previously proposed 4 state could also correspond to a 2 state.
Corts, M. L.*; Rodriguez, W.*; Doornenbal, P.*; Obertelli, A.*; Holt, J. D.*; Lenzi, S. M.*; Menndez, J.*; Nowacki, F.*; Ogata, Kazuyuki*; Poves, A.*; et al.
Physics Letters B, 800, p.135071_1 - 135071_7, 2020/01
Times Cited Count:31 Percentile:96.23(Astronomy & Astrophysics)Excited states in the = 40 isotone Ti were populated via the V(,)Ti reaction at 200 MeV/nucleon at the Radioactive Isotope Beam Factory and studied using -ray spectroscopy. The energies of the and transitions, observed here for the first time, indicate a deformed Ti ground state. These energies are increased compared to the neighboring Cr and Fe isotones, suggesting a small decrease of quadrupole collectivity. The present measurement is well reproduced by large-scale shell-model calculations based on effective interactions, while ab initio and beyond mean-field calculations do not yet reproduce our findings.
Chen, S.*; Lee, J.*; Doornenbal, P.*; Obertelli, A.*; Barbieri, C.*; Chazono, Yoshiki*; Navrtil, P.*; Ogata, Kazuyuki*; Otsuka, Takaharu*; Raimondi, F.*; et al.
Physical Review Letters, 123(14), p.142501_1 - 142501_7, 2019/10
Times Cited Count:47 Percentile:92.65(Physics, Multidisciplinary)no abstracts in English
Kondo, Hiroo*; Kanemura, Takuji*; Park, C. H.*; Oyaizu, Makoto*; Hirakawa, Yasushi; Furukawa, Tomohiro
Fusion Engineering and Design, 146(Part A), p.285 - 288, 2019/09
Times Cited Count:1 Percentile:11.15(Nuclear Science & Technology)Herein, the wall shear stress in a double contraction nozzle has been evaluated experimentally to produce a liquid lithium (Li) target as a beam target for intense fusion neutron sources such as the International Fusion Materials Irradiation Facility (IFMIF), the Advanced Fusion Neutron Source (A-FNS), and the DEMO Oriented Neutron Source (DONES). The boundary layer thickness and wall shear stress are essential physical parameters to understand erosion-corrosion by the high-speed liquid Li flow in the nozzle, which is the key component in producing a stable Li target. Therefore, these parameters were experimentally evaluated using an acrylic mock-up of the target assembly. The velocity distribution in the nozzle was measured by a laser-doppler velocimeter and the momentum thickness along the nozzle wall was calculated using an empirical prediction method. The resulting momentum thickness was used to estimate the variation of the wall shear stress along the nozzle wall. Consequently, the wall shear stress was at the maximum in the second convergent section in front of the nozzle exit.
Ho, D. M. L.*; Nelwamondo, A. N.*; Okubo, Ayako; Ramebck, H.*; Song, K.*; Han, S.-H.*; Hancke, J. J.*; Holmgren, S.*; Jonsson, S.*; Kataoka, Osamu; et al.
Journal of Radioanalytical and Nuclear Chemistry, 315(2), p.353 - 363, 2018/02
Times Cited Count:2 Percentile:20.93(Chemistry, Analytical)The Fourth Collaborative Material Exercise (CMX-4) of the Nuclear Forensics International Technical Working Group (ITWG) registered the largest participation for this exercise in nuclear forensics, with seven of the 17 laboratories participating for the first time. In this paper, participants from five of the first-time laboratories shared their individual experience in this exercise, from preparation to analysis of samples. The exercise proved to be highly useful for testing procedures, repurposing established methods, exercising skills, and improving the understanding of nuclear forensic signatures and their interpretation trough the post-exercise review meeting.
Vostner, A.*; Pong, I.*; Bessette, D.*; Devred, A.*; Sgobba, S.*; Jung, A.*; Weiss, K.-P.*; Jewell, M. C.*; Liu, S.*; Yu, W.*; et al.
IEEE Transactions on Applied Superconductivity, 23(3), p.9500705_1 - 9500705_5, 2013/06
Times Cited Count:12 Percentile:53.02(Engineering, Electrical & Electronic)The ITER Cable-In-Conduit Conductor (CICC) used in the superconducting magnet system consists of a cable made of 300 to 1440 strands housed in a stainless steel tube (a.k.a. jacket or conduit). There are circular, square, as well as circle-in-square jackets, made of either a very low carbon AISI 316LN grade stainless steel or a high Mn austenitic stainless steel developed for ITER called JK2LB. Selected mechanical properties of the base material and weld joint were tested at room temperature and/or cryogenic temperatures ( 7 K). The Domestic Agencies (DAs) reference laboratories and the ITER-IO appointed reference laboratories, CERN and Karlsruhe Institute of Technology (KIT) performed mechanical tests. This paper will compare the test results (e.g. elongation to failure) from different laboratories.
Nakajima, Hideo; Hemmi, Tsutomu; Iguchi, Masahide; Nabara, Yoshihiro; Matsui, Kunihiro; Chida, Yutaka; Kajitani, Hideki; Takano, Katsutoshi; Isono, Takaaki; Koizumi, Norikiyo; et al.
Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 8 Pages, 2013/03
The ITER organization and 6 Domestic Agencies (DA) have been implementing the construction of ITER superconducting magnet systems. Four DAs have already started full scale construction of Toroidal Field (TF) coil conductors. The qualification of the radial plate manufacture has been completed, and JA and EU are ready for full scale construction. JA has qualified full manufacturing processes of the winding pack with a 1/3 prototype and made 2 full scale mock-ups of the basic segments of TF coil structure to optimize and industrialize the manufacturing process. Preparation and qualification of the full scale construction of the TF coil winding is underway by EU. Procurement of the manufacturing equipment is near completion and qualification of manufacturing processes has already started. The constructions of other components of the ITER magnet systems are also going well towards the main goal of the first plasma in 2020.
Yoon, S. W.*; Ahn, J.-W.*; Jeon, Y. M.*; Suzuki, Takahiro; Hahn, S. H.*; Ko, W. H.*; Lee, K. D.*; Chung, J. I.*; Nam, Y. U.*; Kim, J.*; et al.
Nuclear Fusion, 51(11), p.113009_1 - 113009_9, 2011/11
Times Cited Count:33 Percentile:79.01(Physics, Fluids & Plasmas)Typical ELMy H-mode discharges have been achieved on the KSTAR tokamak with the combined auxiliary heating of NBI and ECRH. The minimum external heating power required is about 1.1 MW at a line-averaged density higher than 1.410 m and a toroidal field of 2 T. There is a clear indication of the increase of the L-H threshold power at densities lower than . The initial analysis of energy confinement time () predicted that was higher than the prediction of multi-machine scaling laws by a factor 1.4-1.6. However, when the contribution of fast ion confinement to the total energy was taken into account, better agreed with the scaling results. A clear increase of electron and ion temperature in the pedestal was observed in the H-mode phase but the core ion temperature did not change significantly. On the other hand, the toroidal rotation also increased over all radii in the H-mode phase. The measured ELM frequency was from 30-50 Hz and the drop of total energy appeared to be less than 5%. Between large ELM spikes, small/grassy ELMs were also identified when mixed heating of NBI and ECRH was applied.
Schaffer, M. J.*; Snipes, J. A.*; Gohil, P.*; de Vries, P.*; Evans, T. E.*; Fenstermacher, M. E.*; Gao, X.*; Garofalo, A. M.*; Gates, D. A.*; Greenfield, C. M.*; et al.
Nuclear Fusion, 51(10), p.103028_1 - 103028_11, 2011/10
Times Cited Count:35 Percentile:80.59(Physics, Fluids & Plasmas)Experiments at DIII-D investigated the effects of ferromagnetic error fields similar to those expected from proposed ITER Test Blanket Modules (TBMs). Studied were effects on: plasma rotation and locking; confinement; L-H transition; edge localized mode (ELM) suppression by resonant magnetic perturbations; ELMs and the H-mode pedestal; energetic particle losses; and more. The experiments used a 3-coil mock-up of 2 magnetized ITER TBMs in one ITER equatorial port. The experiments did not reveal any effect likely to preclude ITER operations with a TBM-like error field. The largest effect was slowed plasma toroidal rotation v across the entire radial profile by as much as via non-resonant braking. Changes to global , and were 3 times smaller. These effects are stronger at higher and lower . Other effects were smaller.