Investigation of niobium surface roughness and hydrogen content with different polishing conditions for performance recovery of superconducting QWRs in JAEA Tokai-Tandem Accelerator

Kamiya, Junichiro; Nii, Keisuke*; Kabumoto, Hiroshi; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; Matsuda, Makoto; Moriya, Katsuhiro; Ida, Yoshiaki*; et al.

e-Journal of Surface Science and Nanotechnology (Internet), 21(4), p.344 - 349, 2023/05

https://doi.org/10.1380/ejssnt.2023-046

no abstracts in English

Reports of electropolishing implementation for quarter-wave resonators

Nii, Keisuke*; Ida, Yoshiaki*; Ueda, Hideki*; Yamaguchi, Takanori*; Kabumoto, Hiroshi; Kamiya, Junichiro; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; et al.

Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.334 - 337, 2021/10

no abstracts in English

Conduction-band electronic states of YbInCu studied by photoemission and soft X-ray absorption spectroscopies

Utsumi, Yuki*; Sato, Hitoshi*; Kurihara, Hidenao*; Maso, Hiroyuki*; Hiraoka, Koichi*; Kojima, Kenichi*; Tobimatsu, Komei*; Okochi, Takuo*; Fujimori, Shinichi; Takeda, Yukiharu; et al.

Physical Review B, 84(11), p.115143_1 - 115143_7, 2011/09

https://doi.org/10.1103/PhysRevB.84.115143

We have studied conduction-band (CB) electronic states of a typical valence-transition compound YbInCu by means of temperature-dependent hard X-ray photoemission spectroscopy (HX-PES), soft X-ray absorption spectroscopy (XAS), and soft X-ray photoemission spectroscopy (SX-PES) of the valence band. We have described the valence transition in YbInCu in terms of the charge transfer from the CB to Yb 4 states.

Selective vibrational excitation in the resonant Auger decay following core-to- transitions in NO

Travnikova, O.*; Colin, D.*; Bao, Z.*; Brve, K. J.*; Tanaka, Takahiro*; Hoshino, Masamitsu*; Kato, Hideki*; Tanaka, Hiroshi*; Harries, J.; Tamenori, Yusuke*; et al.

Journal of Electron Spectroscopy and Related Phenomena, 181(2-3), p.129 - 134, 2010/08

https://doi.org/10.1016/j.elspec.2010.05.006

In NO a detailed study of the vibrational distribution of the state reached after decay of core-to- excitation of N terminal, N central and O 1s core levels is reported. We observe a change in the relative intensity of bending versus stretching modes while scanning the photon energy across all three resonances. While this effect is known to be due to the Renner-Teller splitting in the core-excited states, we could derive that the antisymmetric stretching is excited mainly in the decay of the N terminal 1s-to- excitation. An explanation for such selectivity is provided in terms of interplay of vibrational structure on potential energy surfaces of different electronic states involved in the process.

Studies on grouting performance in Mizunami Underground Research Laboratory (Contract research)

Kawamura, Hideki*; Ando, Kenichi*; Noda, Masaru*; Tanaka, Tatsuya*; Matsuda, Takeshi*; Fujii, Haruhiko*; Hashimoto, Shuji*; Ueda, Tadashi*; Matsui, Hiroya; Takeuchi, Shinji; et al.

JAEA-Technology 2009-081, 182 Pages, 2010/03

JAEA-Technology-2009-081.pdf:28.89MB

Grouting has practical importance for the reduction of groundwater inflow into excavations during construction of underground facilities. Considering the performance assessment of a radioactive waste repository, the performance of the engineered barrier system could be adversely affected by a high pH plume generated from grout. Therefore, a quantitative estimation of the effectiveness of grouting and grout material is essential. This study has been performed in the Mizunami URL being excavated in crystalline rock as a part of the Project for Grouting Technology Development for the Radioactive Waste Repository funded by METI, Japan. The aims were to evaluate the applicability of existing grouting technology and to develop methodology to determine the distribution of grout and change in hydraulic properties of the grouted rock volume. The target rock is the volume of rock around a planned refuge niche where the pre-excavation grouting was performed at 200-m depth from ground surface. After excavation of the refuge niche, ten boreholes were drilled and different kinds of investigations were carried out during and after drilling. The results were integrated and groundwater flow analysis of pre and post excavation grouting conditions were carried out to estimate quantitatively the effect of pre-excavation grouting. The results suggest that current pre-excavation grouting technology is effective for reduction of groundwater inflow into excavations and that hydraulic conductivity of the surrounding rock can be reduced by more than one order of magnitude.

Photoabsorption spectra of CFI and thermally dissociated CFI near the C 1s, I 3d and F 1s ionisation thresholds

Tanaka, Takahiro*; Hoshino, Masamitsu*; Kato, Hideki*; Harries, J.; Tamenori, Yusuke*; Ueda, Kiyoshi*; Tanaka, Hiroshi*

Journal of Electron Spectroscopy and Related Phenomena, 164(1-3), p.24 - 27, 2008/07

https://doi.org/10.1016/j.elspec.2008.04.004

We report soft X-ray total ion yield and angular-resolved ion yield spectra of CFI in the C 1s, I 3d and F 1s ionisation regions, and tentatively assign the observed electronic states. Anisotropy in ion yield is observed only for the C 1s transition, indicating that the dipole moment for this transition is parallel to the C. The effusive source of CFI is heated to 800 K to produce a mixture of CF and I, and the resulting spectra are compared to those recorded at room temperature to reveal the first information on the inner-shell excitation of CF.

Research and development of nuclear fusion

Ushigusa, Kenkichi; Seki, Masahiro; Ninomiya, Hiromasa; Norimatsu, Takayoshi*; Kamada, Yutaka; Mori, Masahiro; Okuno, Kiyoshi; Shibanuma, Kiyoshi; Inoue, Takashi; Sakamoto, Keishi; et al.

Genshiryoku Handobukku, p.906 - 1029, 2007/11

no abstracts in English

Coupled electron and atomic kinetics through the solution of the Boltzmann equation for generating time-dependent X-ray spectra

Sherrill, M. E.*; Abdallah, J. Jr.*; Csanak, G.*; Kilcrease, D. P.*; Dodd, E. S.*; Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; et al.

Journal of Quantitative Spectroscopy & Radiative Transfer, 99(1-3), p.584 - 594, 2006/05

https://doi.org/10.1016/j.jqsrt.2005.05.047

In this work, we present a model that solves self-consistently the electron and atomic kinetics to characterize highly non-equilibrium plasmas, in particular for those systems where both the electron distribution function is far from Maxwellian and the evolution of the ion level populations are dominated by time dependent atomic kinetics. In this model, level populations are obtained from a detailed collisional-radiative model where collision rates are computed from a time varying electron distribution function obtained from the solution of the zero-dimensional Boltzmann equation. The Boltzmann collision term includes the effects of electron-electron collisions, electron collisional ionization, excitation and de-excitation. An application for He spectra from a short pulse laser irradiated argon cluster target will be shown to illustrate the results of our model.

Measurement of ' X-ray transitions from 1 m Kr clusters irradiated by high-intensity femtosecond laser pulses

Hansen, S. B.*; Fournier, K. B.*; Faenov, A. Y.*; Magunov, A. I.*; Pikuz, T. A.*; Skobelev, I. Y.*; Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; et al.

Physical Review E, 71(1), p.016408_1 - 016408_9, 2005/01

https://doi.org/10.1103/PhysRevE.71.016408

X-ray line emission from ' transitions in Ne-like Kr and nearby ions has been observed from 1 m Kr clusters irradiated by fs-scale laser pulses at the JAERI facility in Kyoto, Japan. The dependence of X-ray spectral features and intensity on the incident laser intensity is rather weak, indicating that the 1-2 ps cluster lifetimes limit the number of ions beyond Ne-like Kr that can be produced by collisional ionization. A collisional-radiative model based on the relativistic multiconfigured FAC code has been constructed and used to determine that the cluster plasma has electron densities near 10 cm, temperature of a few hundred eV and hot electron fraction of a few percent.

Relativistic laser plasma from micron-sized argon clusters as a debris-free X-ray source for pulse X-ray diffraction

Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; Nakai, Yoshiki*; Tsuji, Koichi*; Yamakawa, Koichi; Hironaka, Yoichiro*; Kishimura, Hiroaki*; et al.

Applied Physics Letters, 85(21), p.5099 - 5101, 2004/11

https://doi.org/10.1063/1.1823589

We have demonstrated diffraction from Si(111) crystal using X-rays from highly ionized Ar ions produced by laser irradiation with an intensity of 610 W/cm and a pulse duration of 30 fs acting upon micron-sized Ar clusters. The measured total photon flux and line width in the He line (3.14 keV) were 410 photons/shot/4sr and 3.7 eV (FWHM), respectively, which is sufficient to utilize as a debris-free light source for time-resolved X-ray diffraction studies.