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Journal Articles

Search for the 6$$alpha$$ condensed state in $$^{24}$$Mg using the $$^{12}$$C+$$^{12}$$C scattering

Fujikawa, Y.*; Kawabata, T.*; Adachi, S.*; Hirose, Kentaro; Makii, Hiroyuki; Nishio, Katsuhisa; Orlandi, R.; Suzaki, Fumi; 13 of others*

Physics Letters B, 848, p.138384_1 - 138384_6, 2024/01

 Times Cited Count:3 Percentile:88.26(Astronomy & Astrophysics)

Journal Articles

Measurement of double-differential neutron yields for iron, lead, and bismuth induced by 107-MeV protons for research and development of accelerator-driven systems

Iwamoto, Hiroki; Nakano, Keita; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Sugihara, Kenta*; Nishio, Katsuhisa; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; et al.

EPJ Web of Conferences, 284, p.01023_1 - 01023_4, 2023/05

 Times Cited Count:0 Percentile:0.21(Nuclear Science & Technology)

For accurate prediction of neutronic characteristics for accelerator-driven systems (ADS) and a source term of spallation neutrons for reactor physics experiments for the ADS at Kyoto University Critical Assembly (KUCA), we have launched an experimental program to measure nuclear data on ADS using the Fixed Field Alternating Gradient (FFAG) accelerator at Kyoto University. As part of this program, the proton-induced double-differential thick-target neutron-yields (TTNYs) and cross-sections (DDXs) for iron, lead, and bismuth have been measured with the time-of-flight (TOF) method. For each measurement, the target was installed in a vacuum chamber on the beamline and bombarded with 107-MeV proton beams accelerated from the FFAG accelerator. Neutrons produced from the targets were detected with stacked, small-sized neutron detectors for several angles from the incident beam direction. The TOF spectra were obtained from the detected signals and the FFAG kicker magnet's logic signals, where gamma-ray events were eliminated by pulse shape discrimination. Finally, the TTNYs and DDXs were obtained from the TOF spectra by relativistic kinematics. The measured TTNYs and DDXs were compared with calculations by the Monte Carlo transport code PHITS with its default physics model of INCL version 4.6 combined with GEM and those with the JENDL-4.0/HE nuclear data library.

Journal Articles

Measurement of 107-MeV proton-induced double-differential thick target neutron yields for Fe, Pb, and Bi using a fixed-field alternating gradient accelerator at Kyoto University

Iwamoto, Hiroki; Nakano, Keita; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Sugihara, Kenta; Nishio, Katsuhisa; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; et al.

Journal of Nuclear Science and Technology, 60(4), p.435 - 449, 2023/04

 Times Cited Count:3 Percentile:63.91(Nuclear Science & Technology)

Double-differential thick target neutron yields (TTNYs) for Fe, Pb, and Bi targets induced by 107-MeV protons were measured using the fixed-field alternating gradient accelerator at Kyoto University for research and development of accelerator-driven systems (ADSs) and fundamental ADS reactor physics research at the Kyoto University Critical Assembly (KUCA). Note that TTNYs were obtained with the time-of-flight method using a neutron detector system comprising eight neutron detectors; each detector has a small NE213 liquid organic scintillator and photomultiplier tube. The TTNYs obtained were compared with calculation results using Monte Carlo-based spallation models (i.e., INCL4.6/GEM, Bertini/GEM, JQMD/GEM, and JQMD/SMM/GEM) and the evaluated high-energy nuclear data library, i.e., JENDL-4.0/HE, implemented in the particle and heavy iontransport code system (PHITS). All models, including JENDL-4.0/HE, failed to predict high-energy peaks at a detector angle of 5$$^{circ}$$. Comparing the energy- and angle-integrated spallation neutron yields at energies of $$le$$20 MeV estimated using the measured TTNYs and the PHITS indicated that INCL4.6/GEM would be suitable for the Monte Carlo transport simulation of ADS reactor physics experiments at the KUCA.

Journal Articles

New $$K$$ isomers in $$^{248}$$Cf

Orlandi, R.; Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Ito, Yuta; Suzaki, Fumi; Nagame, Yuichiro*; et al.

Physical Review C, 106(6), p.064301_1 - 064301_11, 2022/12

 Times Cited Count:1 Percentile:28.09(Physics, Nuclear)

Journal Articles

Measurement of 107-MeV proton-induced double-differential neutron yields for iron for research and development of accelerator-driven systems

Iwamoto, Hiroki; Nakano, Keita; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; Yashima, Hiroshi*; Nishio, Katsuhisa; et al.

JAEA-Conf 2022-001, p.129 - 133, 2022/11

For accurate prediction of neutronic characteristics for accelerator-driven systems (ADS) and a source term of spallation neutrons for reactor physics experiments for the ADS at Kyoto University Critical Assembly (KUCA), we have launched an experimental program to measure nuclear data on ADS using the Fixed Field Alternating Gradient (FFAG) accelerator at Kyoto University. As part of this program, the proton-induced double-differential thick-target neutron-yields (TTNYs) and cross-sections (DDXs) for iron have been measured with the time-of-flight (TOF) method. For each measurement, the target was installed in a vacuum chamber on the beamline and bombarded with 107-MeV proton beams accelerated from the FFAG accelerator. Neutrons produced from the targets were detected with stacked, small-sized neutron detectors composed of the NE213 liquid organic scintillators and photomultiplier tubes, which were connected to a multi-channel digitizer mounted with a field-programmable gate array (FPGA), for several angles from the incident beam direction. The TOF spectra were obtained from the detected signals and the FFAG kicker magnet's logic signals, where gamma-ray events were eliminated by pulse shape discrimination applying the gate integration method to the FPGA. Finally, the TTNYs and DDXs were obtained from the TOF spectra by relativistic kinematics.

Journal Articles

Angular momentum transfer in multinucleon transfer channels of $$^{18}$$O + $$^{237}$$Np

Tanaka, Shoya*; Hirose, Kentaro; Nishio, Katsuhisa; Kean, K. R.*; Makii, Hiroyuki; Orlandi, R.; Tsukada, Kazuaki; Aritomo, Yoshihiro*

Physical Review C, 105(2), p.L021602_1 - L021602_5, 2022/02

 Times Cited Count:2 Percentile:47.44(Physics, Nuclear)

Journal Articles

The $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe cross section from the surrogate ratio method and its effect on the $$^{60}$$Fe nucleosynthesis

Yan, S. Q.*; Li, X. Y.*; Nishio, Katsuhisa; Lugaro, M.*; Li, Z. H.*; Makii, Hiroyuki; Pignatari, M.*; Wang, Y. B.*; Orlandi, R.; Hirose, Kentaro; et al.

Astrophysical Journal, 919(2), p.84_1 - 84_7, 2021/10

 Times Cited Count:1 Percentile:8.24(Astronomy & Astrophysics)

Journal Articles

Chemical characterization of a volatile dubnium compound, DbOCl$$_3$$

Chiera, N. M.*; Sato, Tetsuya; Eichler, R.*; Tomitsuka, Tomohiro; Asai, Masato; Adachi, Sadia*; Dressler, R.*; Hirose, Kentaro; Inoue, Hiroki*; Ito, Yuta; et al.

Angewandte Chemie; International Edition, 60(33), p.17871 - 17874, 2021/08

 Times Cited Count:3 Percentile:21.36(Chemistry, Multidisciplinary)

The formation and the chemical characterization of single atoms of dubnium (Db, element 105), in the form of its volatile oxychloride, was investigated using the on-line gas phase chromatography technique, in the temperature range 350 - 600 $$^circ$$C. Under the exact same chemical conditions, comparative studies with the lighter homologs of group-5 in the Periodic Table clearly indicate the volatility sequence being NbOCl$$_3 > $$ TaOCl$$_3 geq$$ DbOCl$$_3$$. From the obtained experimental results, thermochemical data for DbOCl$$_3$$ were derived. The present study delivers reliable experimental information for theoretical calculations on the chemical properties of transactinides.

Journal Articles

Experimental study of the $$Gamma_{p1}/Gamma_{p0}$$ ratios of resonance states in $$^{8}$$Be for deducing the $$^{7}$$Be($$n$$,$$p_{1}$$)$$^{7}$$Li$$^{*}$$ reaction rate relevant to the cosmological lithium problem

Iwasa, Naohito*; Ishikawa, Shunki*; Kubono, Shigeru*; Sakakibara, T.*; Kominato, Kazuya*; Nishio, Katsuhisa; Matsuda, Makoto; Hirose, Kentaro; Makii, Hiroyuki; Orlandi, R.; et al.

Physical Review C, 103(1), p.015801_1 - 015801_5, 2021/01

 Times Cited Count:1 Percentile:17.58(Physics, Nuclear)

Journal Articles

Measurement of fission-fragment mass distributions in the multinucleon transfer channels of the $$^{18}$$O+$$^{237}$$Np reaction

Vermeulen, M. J.; Nishio, Katsuhisa; Hirose, Kentaro; Kean, K. R.; Makii, Hiroyuki; Orlandi, R.; Tsukada, Kazuaki; Tsekhanovich, I.*; Andreyev, A. N.; Ishizaki, Shoma*; et al.

Physical Review C, 102(5), p.054610_1 - 054610_11, 2020/11

 Times Cited Count:5 Percentile:51.18(Physics, Nuclear)

Journal Articles

Nonresonant $$p$$-wave direct capture and interference effect observed in the $$^{16}$$O$$(n,gamma)^{17}$$O reaction

Nagai, Yasuki*; Kinoshita, Mitsutaka*; Igashira, Masayuki*; Nobuhara, Yuriko*; Makii, Hiroyuki; Mishima, Kenji*; Shima, Tatsushi*; Mengoni, A.*

Physical Review C, 102(4), p.044616_1 - 044616_8, 2020/10

 Times Cited Count:4 Percentile:43.57(Physics, Nuclear)

Journal Articles

New excited 2$$^+$$ and 3$$^-$$ two-proton states in $$_{84}^{210}$$Po$$_{126}$$ populated by two-proton transfer

Dupont, E.*; Astier, A.*; Petrache, C. M.*; Lv, B. F.*; Deloncle, I.*; Kiener, J.*; Orlandi, R.; Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; et al.

Physical Review C, 101(1), p.014309_1 - 014309_6, 2020/01

 Times Cited Count:2 Percentile:24.58(Physics, Nuclear)

Journal Articles

Effects of the nuclear structure of fission fragments on the high-energy prompt fission $$gamma$$-ray spectrum in $$^{235}$$U($$n_{rm th},f$$)

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; L$'e$guillon, R.; Ogawa, Tatsuhiko; Soldner, T.*; K$"o$ster, U.*; Pollitt, A.*; Hambsch, F.-J.*; et al.

Physical Review C, 100(4), p.044610_1 - 044610_7, 2019/10

 Times Cited Count:12 Percentile:76.08(Physics, Nuclear)

Journal Articles

Search for $$alpha$$ decay of $$^{104}$$Te with a novel recoil-decay scintillation detector

Xiao, Y.*; Go, S.*; Grzywacz, R.*; Orlandi, R.; Andreyev, A. N.; Asai, Masato; Bentley, M. A.*; de Angelis, G.*; Gross, C. J.*; Hausladen, P.*; et al.

Physical Review C, 100(3), p.034315_1 - 034315_8, 2019/09

 Times Cited Count:16 Percentile:83.79(Physics, Nuclear)

Journal Articles

Validation of the multinucleon transfer method for the determination of the fission barrier height

Kean, K. R.; Nishio, Katsuhisa; Hirose, Kentaro; Vermeulen, M. J.; Makii, Hiroyuki; Orlandi, R.; Tsukada, Kazuaki; Andreyev, A. N.; Tsekhanovich, I.*; Chiba, Satoshi*

Physical Review C, 100(1), p.014611_1 - 014611_6, 2019/07

 Times Cited Count:3 Percentile:31.66(Physics, Nuclear)

Journal Articles

Observation of the competing fission modes in $$^{178}$$Pt

Tsekhanovich, I.*; Andreyev, A. N.; Nishio, Katsuhisa; Denis-Petit, D.*; Hirose, Kentaro; Makii, Hiroyuki; Matheson, Z.*; Morimoto, Koji*; Morita, Kosuke*; Nazarewicz, W.*; et al.

Physics Letters B, 790, p.583 - 588, 2019/03

 Times Cited Count:33 Percentile:94.77(Astronomy & Astrophysics)

Journal Articles

First ionization potentials of Fm, Md, No, and Lr; Verification of filling-up of 5f electrons and confirmation of the actinide series

Sato, Tetsuya; Asai, Masato; Borschevsky, A.*; Beerwerth, R.*; Kaneya, Yusuke*; Makii, Hiroyuki; Mitsukai, Akina*; Nagame, Yuichiro; Osa, Akihiko; Toyoshima, Atsushi; et al.

Journal of the American Chemical Society, 140(44), p.14609 - 14613, 2018/11

 Times Cited Count:29 Percentile:70.83(Chemistry, Multidisciplinary)

The first ionization potential (IP$$_1$$) yields information on valence electronic structure of an atom. IP$$_1$$ values of heavy actinides beyond einsteinium (Es, Z = 99), however, have not been determined experimentally so far due to the difficulty in obtaining these elements on scales of more than one atom at a time. Recently, we successfully measured IP$$_1$$ of lawrencium (Lr, Z = 103) using a surface ionization method. The result suggests that Lr has a loosely-bound electron in the outermost orbital. In contrast to Lr, nobelium (No, Z = 102) is expected to have the highest IP$$_1$$ among the actinide elements owing to its full-filled 5f and the 7s orbitals. In the present study, we have successfully determined IP$$_1$$ values of No as well as fermium (Fm, Z = 100) and mendelevium (Md, Z = 101) using the surface ionization method. The obtained results indicate that the IP$$_1$$ value of heavy actinoids would increase monotonically with filling electrons up in the 5f orbital like heavy lanthanoids.

Journal Articles

A New detector system for the measurement of high-energy prompt $$gamma$$-rays for low-energy neutron induced fission

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; L$'e$guillon, R.*; Ogawa, Tatsuhiko; Soldner, T.*; Hambsch, F.-J.*; A$"i$che, M.*; Astier, A.*; et al.

Nuclear Instruments and Methods in Physics Research A, 906, p.88 - 96, 2018/10

 Times Cited Count:3 Percentile:29.51(Instruments & Instrumentation)

We have developed a new setup to measure prompt fission $$gamma$$-ray spectra in neutron induced fission up to energies sufficient to reveal the structure associated with giant dipole resonances of fission fragments. The setup consists of multi-wire proportional counters, to detect both fission fragments in coincidence, and two large volume (101.6 mm in diameter and 127.0 mm in length) LaBr$$_{3}$$(Ce) scintillators, to measure the $$gamma$$-rays. The setup was used to obtain the prompt fission $$gamma$$-ray spectrum for thermal neutron induced fission of $$^{235}$$U at the PF1B cold-neutron beam facility of the Institut Laue-Langevin, Grenoble, France. We have successfully measured the $$gamma$$-ray spectrum up to energies of about 20 MeV, what extends the currently known $$gamma$$-ray spectrum limit to higher energies by approximately a factor of two.

Journal Articles

Production of iodine radionuclides using $$^{7}$$Li ion beams

Nishinaka, Ichiro*; Yokoyama, Akihiko*; Washiyama, Koshin*; Makii, Hiroyuki; Hashimoto, Kazuyuki*

Journal of Radioanalytical and Nuclear Chemistry, 314(3), p.1947 - 1965, 2017/12

 Times Cited Count:2 Percentile:19.24(Chemistry, Analytical)

Production cross sections of iodine, tellurium and antimony radionuclides in the 24-59 MeV $$^{7}$$Li + $$^{nat}$$Sn reaction have been measured by the conventional stacked foil technique with $$gamma$$-ray spectrometry. Excitation functions of the production cross sections were compared with a statistical model calculation. The contributions of complete and incomplete fusion in the production of observed radionuclides are discussed from the view points of production routes in the nuclide chart and decays for iodine, tellurium and antimony nuclides. The integral yields of $$^{123,124,125,126}$$I were deduced from the calculated excitation functions in the $$^{7}$$Li induced reactions on Sn isotopes in view of the production of medically important $$^{123,124}$$I. The results are discussed by comparing with literature values in the other reactions.

Journal Articles

Role of multichance fission in the description of fission-fragment mass distributions at high energies

Hirose, Kentaro; Nishio, Katsuhisa; Tanaka, Shoya*; L$'e$guillon, R.*; Makii, Hiroyuki; Nishinaka, Ichiro*; Orlandi, R.; Tsukada, Kazuaki; Smallcombe, J.*; Vermeulen, M. J.; et al.

Physical Review Letters, 119(22), p.222501_1 - 222501_6, 2017/12

 Times Cited Count:50 Percentile:91.01(Physics, Multidisciplinary)

Fission-fragment mass distributions were measured for $$^{237-240}$$U, $$^{239-242}$$Np and $$^{241-244}$$Pu populated in the excitation-energy range from 10 to 60 MeV by multi-nucleon transfer channels in the reaction $$^{18}$$O + $$^{238}$$U at the JAEA tandem facility. Among them, the data for $$^{240}$$U and $$^{240,241,242}$$Np were observed for the first time. It was found that the mass distributions for all the studied nuclides maintain a double-humped shape up to the highest measured energy in contrast to expectations of predominantly symmetric fission due to the washing out of nuclear shell effects. From a comparison with the dynamical calculation based on the fluctuation-dissipation model, this behavior of the mass distributions was unambiguously attributed to the effect of multi-chance fission.

218 (Records 1-20 displayed on this page)