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Tamura, Koji; Oba, Hironori; Saeki, Morihisa; Taguchi, Tomitsugu*; Lim, H. H.*; Taira, Takunori*; Wakaida, Ikuo
Journal of Nuclear Science and Technology, 58(4), p.405 - 415, 2021/04
Times Cited Count：15 Percentile：82.17(Nuclear Science & Technology)Radiation dose rate effects on the properties of a compact fiber-optic laser-induced breakdown spectroscopy (LIBS) system with a monolithic Nd:YAG/Cr:YAG composite ceramics were investigated for remote analysis in hazardous environment. To investigate radiation effects on the LIBS signal, properties related to the Nd:YAG laser operation such as oscillation threshold, output energy, oscillation timing, temporal pulse shape, and beam profile were measured as a function of the radiation dose rate from 0 to 10 kGy/hr in view of their influences to the signal. LIBS spectra of zirconium metal were measured under irradiation. Although signal intensity decreased considerably by irradiation, informative spectra were well obtained even at the maximum radiation dose rate. From the comparison of the LIBS-related parameters among the laser properties, signal reduction was mainly ascribed to the pulse energy reduction. Scintillation emission spectra were also measured from the ceramics during the irradiation, where the signal intensity increased linearly with the dose rate. The results show that the developed system.
PdSi
Hirschberger, M.*; Nakajima, Taro*; Kriener, M.*; Kurumaji, Takashi*; Spitz, L.*; Gao, S.*; Kikkawa, Akiko*; Yamasaki, Yuichi*; Sagayama, Hajime*; Nakao, Hironori*; et al.
Physical Review B, 101(22), p.220401_1 - 220401_6, 2020/06
Times Cited Count：51 Percentile：90.84(Materials Science, Multidisciplinary)Saeki, Morihisa*; Matsumura, Daiju; Yomogida, Takumi; Taguchi, Tomitsugu*; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*
Journal of Physical Chemistry C, 123(1), p.817 - 824, 2019/01
Times Cited Count：17 Percentile：53.18(Chemistry, Physical)Reaction kinetics of laser-induced particle formation in an aqueous solution of PdCl
was investigated by transmission electron microscope (TEM) and dispersive X-ray absorption fine structure (DXAFS). The Pd particle was generated by irradiation of nanosecond pulsed 266-nm laser. The TEM observation showed dependence of the particle size on the laser fluence and promotion of the particle growth by irradiation of high-fluence laser. The DXAFS data give us the Pd
concentration. Temporal changes of the Pd concentration analyzed based on Finke-Watzky two step mechanism. The analysis elucidates that the laser photon contributes to the reduction of the PdCl ion by the one-photon process and to the autocatalytic growth of the Pd particles by the multi-photon process.
Saeki, Morihisa*; Taguchi, Tomitsugu*; Oba, Hironori*; Matsumura, Daiju; Tsuji, Takuya; Yomogida, Takumi
Denki Gakkai Kenkyukai Shiryo, Denshi Zairyo Kenkyukai (EFM-17-010
021), p.15 - 18, 2017/09
Irradiation of nanosecond pulsed UV laser into a solution of palladium ion leads to formation of palladium particles with sub-micron size particles by time-resolved X-ray absorption spectroscopy.
Saeki, Morihisa; Taguchi, Tomitsugu; Nakashima, Nobuaki*; Oba, Hironori
Journal of Photochemistry and Photobiology A; Chemistry, 299, p.189 - 193, 2015/02
Times Cited Count：18 Percentile：41.02(Chemistry, Physical)Saeki, Morihisa; Esaka, Fumitaka; Taguchi, Tomitsugu; Oba, Hironori
JAEA-Research 2012-030, 16 Pages, 2012/11
JAEA-Research-2012-030.pdf:2.76MB
We proposed separation technique of platinum-group metals (PGMs) from a solution of high-level radioactive waste by using laser-induced particle formation, and performed its proof-of-principle experiment. The simulated solution of high-level radioactive liquid wastes (HLLW) was prepared by dissolving palladium (Pd), rhodium (Rh), ruthenium (Ru) and neodymium (Nd) into distilled water. The Nd metal was added as representative of lanthanide and minor actinide. After 40-min irradiation of a mixture of the simulated solution of HLLW and ethanol (v/v = 1/1) with a UV laser (266 nm, 20 mJ), the Pd, Rh and Ru metals were separated from the Nd ion as particle with sub-micron size. The PGM particles were recovered by filtration and centrifugation. Analysis of ion concentration in the sample solution by ICP-AES suggested that the Pd, Rh and Ru metals were recovered with efficiency of 100%, 94-99%, 65-69%, while the Nd ion was completely kept in the sample solution.
Taguchi, Yasujiro*; Sakai, Hideaki*; Okuyama, Daisuke*; Ishiwata, Shintaro*; Fujioka, Jun*; Fukuda, Tatsuo; Hashizume, Daisuke*; Kagawa, Fumitaka*; Takahashi, Yoichiro*; Shimano, Ryo*; et al.
Physica B; Condensed Matter, 407(11), p.1685 - 1688, 2012/06
Times Cited Count：5 Percentile：22.64(Physics, Condensed Matter)Oba, Hironori; Suzuki, Hiroshi*; Esaka, Fumitaka; Taguchi, Tomitsugu; Yamada, Yoichi; Yamamoto, Hiroyuki; Sasase, Masato*; Yokoyama, Atsushi
Journal of the Vacuum Society of Japan, 52(6), p.292 - 295, 2009/07
no abstracts in English
Chandrasekaran, N.*; Soga, Tetsuo*; Inuzuka, Yosuke*; Taguchi, Hironori*; Imaizumi, Mitsuru*; Oshima, Takeshi; Jimbo, Takashi*
Japanese Journal of Applied Physics, 43(10A), p.L1302 - L1304, 2004/10
Times Cited Count：7 Percentile：30.68(Physics, Applied)no abstracts in English
Hiratsuka, Hiroshi*; Okamoto, Takahiro*; Kuroda, Satoshi*; Okutsu, Tetsuo*; Maeoka, Hironori*; Taguchi, Mitsumasa; Yoshinaga, Tetsutaro*
Research on Chemical Intermediates, 27(1-2), p.137 - 153, 2001/02
Times Cited Count：10 Percentile：19.24(Chemistry, Multidisciplinary)no abstracts in English
Saeki, Morihisa*; Matsumura, Daiju; Tsuji, Takuya; Yomogida, Takumi; Taguchi, Tomitsugu*; Oba, Hironori*
no journal, ,
Irradiation of a nanosecond pulsed UV laser into a solution of palladium ion leads to formation of palladium particles with submicron size (100-800 nm). We investigate formation mechanism of the submicron size particles by time-resolved X-ray absorption fine structure (XAFS) spectroscopy.
Saeki, Morihisa*; Asai, Shiho; Yomogida, Takumi; Hanzawa, Yukiko; Taguchi, Tomitsugu*; Horita, Takuma; Kitatsuji, Yoshihiro; Oba, Hironori*
no journal, ,
Platinum-group metals (PGMs), such as Pd, Ru, and Rh are generated by nuclear fission of U and can be found in spent nuclear fuel (SNF) and high-level radioactive waste (HLW). Separation techniques for PGMs from HLW have been investigated for the safety assessment of HLW and the reuse of PGMs as resources. Among such PGMs, only Pd has a long-lived radionuclide 
Pd. Accordingly, the precise measurement of the amount of Pd in HLW is essential for the long-term safety management of HLW. The determination of Pd requires a reliable separation technique that allows selective Pd recovery with high purity. We developed a new separation technique specialized for PGMs. The technique involves UV-laser irradiation that induces selective reduction of ions of PGMs. The reduced PGMs can be readily recovered as precipitates. At the conference, the separation performances of PGMs and some applications of our technique will be discussed.
Tamura, Koji; Nakanishi, Ryuzo; Oba, Hironori; Saeki, Morihisa; Taguchi, Tomitsugu*; Lim, H. H.*; Taira, Takunori*; Wakaida, Ikuo
no journal, ,
Saeki, Morihisa; Taguchi, Tomitsugu; Matsumura, Daiju; Nakashima, Nobuaki*; Oba, Hironori
no journal, ,
no abstracts in English
Saeki, Morihisa; Matsumura, Daiju; Yomogida, Takumi; Taguchi, Tomitsugu; Tsuji, Takuya; Kusano, Shogo*; Miyazaki, Tatsuya*; Takao, Koichiro*; Oba, Hironori; Nakashima, Nobuaki*
no journal, ,
Recently, we found that photo-induced particle formation of Pd was promoted by coexistence of molybdenum anion in aqueous solution. In this study, we performed in-situ time-resolved XAFS measurement in the photoreduction of Pd in presence of various concentration of molybdenum anion. The effect of molybdenum addition on photo-induced particle formation of Pd will be discussed based on the relationship between the photoreduction rate of Pd and the concentration of molybdenum anion.
Saeki, Morihisa; Matsumura, Daiju; Yomogida, Takumi; Taguchi, Tomitsugu; Tsuji, Takuya; Kusano, Shogo*; Miyazaki, Tatsuya*; Takao, Koichiro*; Oba, Hironori; Nakashima, Nobuaki*
no journal, ,
no abstracts in English
using ns pulsed UV laser; Dependence of chemical kinetics on laser pulse energySaeki, Morihisa*; Yomogida, Takumi; Matsumura, Daiju; Nakanishi, Ryuzo*; Taguchi, Tomitsugu*; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*
no journal, ,
In the absence of a photoactivator, the laser-induced particle formation in an H
O/ EtOH solution of PdCl was performed by three kinds of irradiation condition using fourth harmonics of the pulsed UV laser (266 nm). In the irradiation, pulsed laser energy was arranged to 5, 10 and 25 mJ, where average laser power is kept to 250 mW. The reaction kinetics of the laser-induced particle formation was observed using dispersive XAFS measurement. About half of Pd ions were reduced with 5 mJ pulsed laser irradiation. In contrast, all Pd ions were reduced with 25 mJ pulsed laser irradiation. The result elucidates that the laser photon contributes to the generation of Pd metals by the multi-photon process.
Saeki, Morihisa; Taguchi, Tomitsugu; Oba, Hironori
no journal, ,
In this work, we have developed a new separation and recovery technique by combining laser-induced particle formation and solvent extraction process.
nanoparticlesSaeki, Morihisa; Taguchi, Tomitsugu; Iwanade, Akio*; Oba, Hironori
no journal, ,
no abstracts in English
Saeki, Morihisa; Taguchi, Tomitsugu; Matsumura, Daiju; Nakashima, Nobuaki*; Oba, Hironori
no journal, ,
no abstracts in English
