JOPSS - Search Results

Journal Articles

First nuclear transmutation of $^{237}$ Np and $^{241}$ Am by accelerator-driven system at Kyoto University Critical Assembly

Pyeon, C. H.*; Yamanaka, Masao*; Oizumi, Akito; Fukushima, Masahiro; Chiba, Go*; Watanabe, Kenichi*; Endo, Tomohiro*; Van Rooijen, W. G.*; Hashimoto, Kengo*; Sakon, Atsushi*; et al.

Journal of Nuclear Science and Technology, 56(8), p.684 - 689, 2019/08

https://doi.org/10.1080/00223131.2019.1618406

Times Cited Count：12 Percentile：69.28(Nuclear Science & Technology)

This study demonstrates, for the first time, the principle of nuclear transmutation of minor actinide (MA) by the accelerator-driven system (ADS) through the injection of high-energy neutrons into the subcritical core at the Kyoto University Critical Assembly. The main objective of the experiments is to confirm fission reactions of neptunium-237 ( $^{237}$ Np) and americium-241 ( $^{241}$ Am), and capture reactions of $^{237}$ Np. Subcritical irradiation of $^{237}$ Np and $^{241}$ Am foils is conducted in a hard spectrum core with the use of the back-to-back fission chamber that obtains simultaneously two signals from specially installed test ( $^{237}$ Np or $^{241}$ Am) and reference (uranium-235) foils. The first nuclear transmutation of $^{237}$ Np and $^{241}$ Am by ADS soundly implemented by combining the subcritical core and the 100 MeV proton accelerator, and the use of a lead-bismuth target, is conclusively demonstrated through the experimental results of fission and capture reaction events.

Journal Articles

On-line diffusion tracing in Li ionic conductors by the short-lived radioactive beam of $^{8}$ Li

Jeong, S.-C.*; Katayama, Ichiro*; Kawakami, Hirokane*; Watanabe, Yutaka*; Ishiyama, Hironobu*; Imai, Nobuaki*; Hirayama, Yoshikazu*; Miyatake, Hiroari; Sataka, Masao; Sugai, Hiroyuki; et al.

Japanese Journal of Applied Physics, 47(8), p.6413 - 6415, 2008/08

https://doi.org/10.1143/JJAP.47.6413

Times Cited Count：5 Percentile：21.82(Physics, Applied)

A non-destructive and on-line diffusion tracing in Li ionic conductors has been demonstrated. As a tracer, pulsed beam of $^{8}$ Li was implanted into LiGa. By analyzing the time dependent yield of the -particles decaying from $^{8}$ Li, diffusion coefficients were extracted with a high accuracy. The ordering of Li vacancies in the Li-deficient phase of LiGa was observed for the first time in terms of the Li diffusion.

Journal Articles

New insight into hierarchical structures of carbon black dispersed in polymer matrices; A Combined small-angle scattering study

Koga, Tadanori*; Hashimoto, Takeji; Takenaka, Mikihito*; Aizawa, Kazuya; Amino, Naoya*; Nakamura, Masao*; Yamaguchi, Daisuke; Koizumi, Satoshi

Macromolecules, 41(2), p.453 - 464, 2008/01

https://doi.org/10.1021/ma071867l

Times Cited Count：136 Percentile：96.03(Polymer Science)

Using a combined ultra-small-angle and small-angle scattering method of neutrons and X-rays, we investigated hierarchical structures of carbon black (CB) highly loaded in polyisoprene (PI) and poly-(styrene-random-butadiene) copolymer (SBR) under mechanical field (defined respectively as CB/PI and CB/SBR) as well as in toluene under a sonic field (defined as CB/toluene). Comparison of the scattering profiles from CB/PI and CB/SBR with CB/toluene clarified that (1) the smallest structure elements of CB in PI and SBR were composed of the several unbreakable units bounded together by polymer chains (defined as "dispersible units") and (2) sizes and shapes of the dispersible units depended on the polymer matrix. (3) Moreover, the enlarged size of the dispersible unit in PI was found to enlarge the upper cutoff length of the mass-fractal structure in PI, while the mass-fractal dimensions themselves remained unchanged between PI and SBR.

Journal Articles

Diffusion of $^{8}$ Li short-lived radiotracer in Li ionic conductors of NaTl-type intermetallic compounds

Sugai, Hiroyuki; Sataka, Masao; Okayasu, Satoru; Ichikawa, Shinichi; Nishio, Katsuhisa; Mitsuoka, Shinichi; Nakanoya, Takamitsu; Osa, Akihiko; Sato, Tetsuya; Hashimoto, Takashi; et al.

Defect and Diffusion Forum, 273-276, p.667 - 672, 2008/00

Journal Articles

Measurement of self-diffusion coefficients in Li ionic conductors by using the short-lived radiotracer of Li

Jeong, S.-C.*; Katayama, Ichiro*; Kawakami, Hirokane*; Watanabe, Yutaka*; Ishiyama, Hironobu*; Imai, Nobuaki*; Hirayama, Yoshikazu*; Miyatake, Hiroari; Sataka, Masao; Okayasu, Satoru; et al.

Journal of Phase Equilibria and Diffusion, 26(5), p.472 - 476, 2005/09

https://doi.org/10.1007/s11669-005-0037-0

Authors developed a radiotracer method for diffusion studies in solids. The experimental test was performed by the measurement of the diffusion coefficients of Li in a sample of the compound LiAl using an -emitting radiotracer of Li(T $_{1/2}$ = 0.84 s). It was found that the time-dependent yields of the alpha particles from the diffusing 8Li that was initially implanted in the sample could be used as a measure of the diffusivity of the tracer in a nondestructive way. The method was applied to measure the self-diffusion coefficients of Li in LiGa, and for investigating how the Li diffusion in the Li ionic conductors is affected by the concentration of atomic defects.

Journal Articles

Measurement of diffusion coefficients in solids by the short-lived radioactive beam of $^{8}$ Li

Jeong, S.-C.*; Katayama, Ichiro*; Kawakami, Hirokane*; Watanabe, Yutaka*; Ishiyama, Hironobu*; Miyatake, Hiroari*; Sataka, Masao; Okayasu, Satoru; Sugai, Hiroyuki; Ichikawa, Shinichi; et al.

Nuclear Instruments and Methods in Physics Research B, 230(1-4), p.596 - 600, 2005/04

https://doi.org/10.1016/j.nimb.2004.12.107

Times Cited Count：6 Percentile：44.45(Instruments & Instrumentation)

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