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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：12 Percentile：84.32(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.
Miyajima, Yusuke*; Saito, Ayaka*; Kagi, Hiroyuki*; Yokoyama, Tatsunori; Takahashi, Yoshio*; Hirata, Takafumi*
Geostandards and Geoanalytical Research, 45(1), p.189 - 205, 2021/03
Times Cited Count：5 Percentile：21.77(Geochemistry & Geophysics)Uncertainty for elemental and isotopic analyses of calcite by LA-ICP-MS is largely controlled by the homogeneity of the reference materials (RMs) used for normalization and validation. In order to produce calcite RMs with homogeneous elemental and isotopic compositions, we incorporated elements including U, Pb, and rare earth elements into calcite through heat- and pressure-induced crystallization from amorphous calcium carbonate that was precipitated from element-doped reagent solution. X-ray absorption spectra showed that U was present as U(VI) in the synthesized calcite, probably with a different local structure from that of aqueous uranyl ions. The uptake rate of U by our calcite was higher in comparison to synthetic calcite of previous studies. Variations of element mass fractions in the calcite were better than 12% 2RSD, mostly within 7%. The 
Pb/
Pb ratio in the calcite showed 
1% variations, while the 
U/Pb ratio showed 3-24% variations depending on element mass fractions. Using the synthetic calcite as primary RMs, we could date a natural calcite RM, WC-1, with analytical uncertainty as low as 3%. The method presented can be useful to produce calcite with controlled and homogeneous element mass fractions, and is a promising alternative to natural calcite RMs for U-Pb geochronology.
Nakanishi, Ryuzo; Oba, Hironori; Saeki, Morihisa; Wakaida, Ikuo; Tanabe, Rie*; Ito, Yoshiro*
Optics Express (Internet), 29(4), p.5205 - 5212, 2021/02
Times Cited Count：13 Percentile：83.13(Optics)Laser-induced breakdown spectroscopy (LIBS) combined with liquid jets was applied to the detection of trace sodium (Na) in aqueous solutions. The sensitivities of two types of liquid jets were compared: a liquid cylindrical jet with a diameter of 500 
m and a liquid sheet jet with a thickness of 20 m. Compared with the cylindrical jet, the liquid sheet jet effectively reduced the splash from the laser-irradiated surface and produced long-lived luminous plasma. The limit of detection (LOD) of Na was determined to be 0.57 g/L for the sheet jet and 10.5 g/L for the cylindrical jet. The LOD obtained for the sheet jet was comparable to those obtained for commercially available inductively coupled plasma emission spectrometers.
Matsumoto, Ayumu
Reza Kako Gakkai-Shi, 23(3), p.222 - 231, 2016/10
no abstracts in English
Lezhnin, K.*; Kamenets, F. F.*; Beskin, V.*; Kando, Masaki; Esirkepov, T. Z.; Bulanov, S. V.
Physics of Plasmas, 22(3), p.033112_1 - 033112_9, 2015/03
Times Cited Count：6 Percentile：28.43(Physics, Fluids & Plasmas)Fukuda, Yuji; Yamakawa, Koichi
Progress in Ultrafast Intense Laser Science II, p.231 - 251, 2007/00
To better understand a fundamental aspect of the laser cluster interaction, we have carried out systematic investigations of X-ray radiation properties of high-density and high-temperature cluster plasma, created by the action of superintense laser irradiation. The interrelationship between the X-ray radiation properties and ion kinetic energies has been for the first time examined by the simultaneous measurements of X-ray radiation spectra and ion energy spectra. Time scale and mechanism of X-ray emission process have been discussed based on a time-dependent plasma kinetics model. Moreover, in order to demonstrate the practical capability of X-rays thus produced, the pulse X-ray diffraction has been examined from Si crystal with this source.
Kawano, Yasunori; Nakano, Tomohide; Asakura, Nobuyuki; Tamai, Hiroshi; Isayama, Akihiko; Kondoh, Takashi; Hatae, Takaki; Takenaga, Hidenobu; Ide, Shunsuke
Purazuma, Kaku Yugo Gakkai-Shi, 81(10), p.743 - 744, 2005/10
Electron density of post-disruption runaway plasmas in JT-60U has been measured by the tangential CO
laser interferometer. Increases in electron density after the first drop of runaway plasma current have been observed during a fast termination phase of the runaway plasma. At the second current drop, an increase in electron density with multiple spikes or oscillation with the period of 1 ms has been found. It is suggested that the increased electron density seems to take part in the shorter current decay time after the second current drop.
Eidmann, K.*; Kawachi, Tetsuya; Marcinkevicius, A.*; Bartlome, R.*; Tsakiris, G.*; Witte, K.*; Teubner, U.*
Physical Review E, 72(3), p.036413_1 - 036413_9, 2005/09
Times Cited Count：33 Percentile：77.37(Physics, Fluids & Plasmas)In order to clarify the mechanism of high-order harmonics generation from solid target, we investigated the emission from rear side of the foil target irradiated by an intense Ti:S laser pulse, duration of 150 fs. The comparison of the exprimental result with our Particle-in-Cell simulation implies that rear side emission is caused by energetic electron bunches which is generated at the front side by resonance absorption.
Kawachi, Tetsuya; Nagashima, Keisuke; Kishimoto, Maki; Hasegawa, Noboru; Tanaka, Momoko; Ochi, Yoshihiro; Nishikino, Masaharu; Kawazome, Hayato; Tai, R.; Namikawa, Kazumichi*; et al.
Proceedings of SPIE's International Symposium on Optics and Photonics 2005, Vol.5919, p.59190L_1 - 59190L_11, 2005/09
Recent results of the X-ray laser research in Advanced Photon Research (APR) Center in JAERI are reported. In the application of the nickel-like silver laser at a wavelength of 13.9 nm, we report the observation of the microscopic polarization clusters in ferroelectrics material such as BaTi03 by use of the X-ray speckle technique, and other experiments such as photo-ionization of inner-shell electrons are intoroduced. In the development of high quality X-ray laser beam, recently we demonstrated temporally coherent X-ray beam at 23.6 nm, in which the high-order harmonics light was injected into the Ne-like Mn X-ray amplifier. We also mention about the development of new X-ray laser driver laser, which is based on 2 beams of zig-zag slab Nd:glass lasers with 0.1 Hz repetition-rate, and each beam line can provide 10 J output energy, and 1 ps duration.
Kando, Masaki; Masuda, Shinichi; Zhidkov, A.*; Yamazaki, Atsushi; Kotaki, Hideyuki; Kondo, Shuji; Homma, Takayuki*; Kanazawa, Shuhei; Nakajima, Kazuhisa; Hayashi, Yukio; et al.
Physical Review E, 71(1), p.015403_1 - 015403_4, 2005/01
Times Cited Count：33 Percentile：77.37(Physics, Fluids & Plasmas)no abstracts in English
Oba, Hironori; Saeki, Morihisa; Yokoyama, Atsushi
Proceedings of Plasma Science Symposium 2005/22nd Symposium on Plasma Processing (PSS-2005/SPP-22), p.331 - 332, 2005/01
A plasma produced by a XeCl laser ablation of boron compound was investigated using ion probes and a quadrupole mass spectrometer. Although the ablated neutral boron atoms had a natural abundance ratio, the isotope ratio of singly ionized boron atoms having a greatly different from the natural abundance ratio was observed. The observed isotope ratio of boron ions was different from the natural abundance.
Kondoh, Takashi; Costley, A. E.*; Sugie, Tatsuo; Kawano, Yasunori; Malaquias, A.*; Walker, C. I.*
Review of Scientific Instruments, 75(10), p.3420 - 3422, 2004/10
Times Cited Count：23 Percentile：72.22(Instruments & Instrumentation)In order to measure the line average electron density on ITER, a CO laser interferometer/polarimeter system is being developed. The design of the interferometer/polarimeter is improved from the previous design, which uses CO and CO laser, on the basis of experience gained with a dual CO system on JT-60U in which good reliability was confirmed for both interferometry and polarimetry operation. The performance of the dual CO laser meets requirements for ITER (accuracy; 1%, time resolution; 1 ms).
Utsumi, Takayuki*; Matsukado, Koji*; Daido, Hiroyuki; Esirkepov, T. Z.; Bulanov, S. V.*
Applied Physics A, 79(4-6), p.1185 - 1187, 2004/09
Times Cited Count：10 Percentile：40.13(Materials Science, Multidisciplinary)no abstracts in English
Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; Kishimoto, Yasuaki; Yamakawa, Koichi; Faenov, A. Y.*; Magunov, A. I.*; Pikuz, T. A.*; et al.
Laser and Particle Beams, 22(3), p.215 - 220, 2004/07
Times Cited Count：41 Percentile：78.95(Physics, Applied)High resolution K-shell spectra of a plasma created by superintense laser irradiation of micron-sized Ar clusters have been measured with an intensity above 10
W/cm
and a pulse duration of 30 fs. The total photon flux of 2
10
photons/pulse was achieved for He
resonant line of Ar (
=3.9491 AA , 3.14 keV). In parallel with X-ray measurements, energy distributions of emitted ions have been measured. The multiply-charged ions with kinetic energies up to 800 keV were observed. It is found that hot electrons produced by high contrast laser pulses allow the isochoric heating of clusters and shift the ion balance towards the higher charge states, which enhances both the X-ray line yield of the He-like argon ion and the ion kinetic energy.
Kawano, Yasunori; Chiba, Shinichi; Inoue, Akira*
Review of Scientific Instruments, 75(1), p.279 - 280, 2004/01
Times Cited Count：12 Percentile：53.69(Instruments & Instrumentation)It has been successful to apply CVD diamond plate as the vacuum window for infrared CO laser interferometry and polarimetry for electron density measurement in the JT-60U tokamak. In comparison with to use the conventional zinc-selenide windows, the Faraday rotation component at diamond windows was small as negligible. This resulted in the improvement of the Faraday rotation measurement for a tokamak plasma by polarimetry.
Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; Kishimoto, Yasuaki; Yamakawa, Koichi; Faenov, A. Y.*; Magunov, A. I.*; Pikuz, T. A.*; et al.
Laser-Generated & Other Lab. X-Ray & EUV Sources (Proceedings of SPIE Vol.5196), p.234 - 243, 2004/00
High resolution X-ray emission spectra of plasma created by laser irradiation of rare-gas (Ar, Kr, Xe) clusters have been measured at laser intensities over 10 W/cm and 30-fs pulse duration. To make these measurements possible, in addition to the effort to decrease a prepulse intensity using Pockels cell switches, micron-size clusters were produced using a specially designed conical nozzle. The Boltzmann equation and a detailed collisional radiative model are solved simultaneously as a function of time to model the time integrated X-ray spectra of the transient plasma. The results are quantitatively in good agreement with the experimentally observed X-ray emission spectra of Ar clusters.
Abdallah, J. Jr.*; Csanak, G.*; Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; Yamakawa, Koichi; Faenov, A. Y.*; Magunov, A. I.*; et al.
Physical Review A, 68(6), p.063201_1 - 063201_8, 2003/12
Times Cited Count：53 Percentile：87.19(Optics)The Boltzmann Equation and a detailed collisional radiative model are solved simultaneously as a function of time to model the time integrated X-ray spectra of the transient plasma produced by a high intensity ultrafast laser source. The results are in agreement with highly resolved F-like to He-like K-shell emission spectra recorded recently during ultrashort laser experiments with argon cluster targets in Japan.
Fukuda, Yuji; Yamakawa, Koichi; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; Abdallah, J. Jr.*; Csanak, G.*; Faenov, A. Y.*; Magunov, A. I.*; et al.
JETP Letters, 78(3), p.115 - 118, 2003/08
Times Cited Count：30 Percentile：77.51(Physics, Multidisciplinary)We have measured the X-ray emission spectra of a plasma generated by laser radiation with an intensity above 10 W/cm and a pulse duration of 30 fs acting uon an argon jet target with a large aboundance of micron-sized clusters. The time variation of the X-ray yeild from various multiplicities, calculated within the framework of a nonstationary kinetic model, shows a good qualitative agreement with the experimental time-integrated spectrum.
Kishimoto, Yasuaki
Purazuma, Kaku Yugo Gakkai-Shi, 79(5), p.460 - 463, 2003/05
This is a collection of review article related to the "Multiple Time and Spatial Scale Plasma Simulation" of various fields including fundamental research area of self-organization, magnetic and laser fusion field, space and astrophysics field where a plasma plays an essential roles.
laser for ion energy spectrum measurements in JT-60UKondoh, Takashi; Miura, Yukitoshi; Lee, S.*; Richards, R. K.*; Hutchinson, D. P.*; Bennett, C. A.*
Review of Scientific Instruments, 74(3), p.1642 - 1645, 2003/03
Times Cited Count：20 Percentile：68.22(Instruments & Instrumentation)Measurements of energy spectrum and density profile of confined alpha-particles are required for ITER. Several methods have been proposed, however, a measurement technique hasn't been established yet. A collective Thomson scattering (CTS) system based on a pulsed CO laser is being developed to demonstrate feasibility of alpha-particle diagnostics for ITER. The pulse laser (15J, 1m, 0.6 m) and a wide band (~ 8GHz) heterodyne receiver with a quantum-well infrared photodetector (QWIP) have been developed and installed in the JT-60U tokamak. Stray light is reduced by a notch filter with hot CO gas. Heterodyne receiver is absolutely calibrated using large area blackbody radiation source. Scattered signal from JT-60U plasma has not detected because of electrical noise originated from discharge of the pulsed laser and stray signal caused by impurity of the spectrum of the pulsed laser.
