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Nishiuchi, Mamiko; Sakaki, Hironao
Isotope News, (739), p.15 - 20, 2015/11
We introduce the multi-charged heavy-ion acceleration mechanisms and the recent results obtained at the KPSI JAEA. We also propose the novel application of the laser-driven multi-charged heavy ion beam.
Nishiuchi, Mamiko; Sakaki, Hironao
Nihon Genshiryoku Gakkai-Shi ATOMO
, 57(10), p.677 - 681, 2015/10
Light, such as, High intensity short pulse laser interacting with the thin-foil target, accelerates the almost fully stripped Iron ions towards the energy of 0.9 GeV. It is quite difficult for the conventional ion sources to make the highly charged heavy ions within few tens of femtoseconds and at the same time accelerates them towards higher energies. The achievement explained here is one new step towards the novel type compact ion sources.
Abe, Hiroshi; Shimomura, Takuya; Tokuhira, Shinnosuke*; Shimada, Yukihiro*; Takenaka, Yusuke*; Furuyama, Yuta*; Nishimura, Akihiko; Uchida, Hirohisa*; Daido, Hiroyuki; Oshima, Takeshi
Proceedings of 7th International Congress on Laser Advanced Materials Processing (LAMP 2015) (Internet), 4 Pages, 2015/08
A short pulse laser (the nanosecond and femtosecond) was applied to hydrogen absorbing alloys surface layer, and a surface modification experiment was put into effective to aim at improvement of hydrogen adsorption functionally. It was investigated about correlation between an initial hydrogen absorption reaction rate of hydrogen alloys and a laser irradiation in this research. The laser irradiation condition was done with pulse width 100 fsec and energy 0.2 - 3.4 mJ/pulse. It blazed down on hydrogen absorbing alloys (LaNi
Al
) and changed local order in the surface. As a result, the initial hydrogen absorption reaction rate was 1.5 - 3.0 times as fast as a irradiated sample, and the result and laser irradiated sample found out that a hydrogen absorption function improves. A laser irradiation can conclude to be effective in surface modification of the hydrogen storage materials.
Nishiuchi, Mamiko; Choi, I. W.*; Daido, Hiroyuki; Nakamura, Tatsufumi*; Pirozhkov, A. S.; Yogo, Akifumi*; Ogura, Koichi; Sagisaka, Akito; Orimo, Satoshi; Daito, Izuru*; et al.
Plasma Physics and Controlled Fusion, 57(2), p.025001_1 - 025001_9, 2015/02
Times Cited Count：3 Percentile：13.67(Physics, Fluids & Plasmas)Projection images of a metal mesh produced by directional MeV electron beam together with directional proton beam, emitted simultaneously from a thin foil target irradiated by an ultrashort intense laser. The mesh patterns are projected to each detector by the electron beam and the proton beam originated from tiny virtual sources of 
20 micron meter and 10 micron meter diameters, respectively. Based on the observed quality and magnification of the projection images, we estimate sizes and locations of the virtual sources for both beams and characterize their directionalities. To carry out physical interpretation of the directional electron beam qualitatively, we perform 2D particle-in-cell simulation which reproduces a directional escaping electron component, together with a non-directional dragged-back electron component, the latter mainly contributes to building a sheath electric field for proton acceleration.
Nishimura, Akihiko; Takenaka, Yusuke*; Furuyama, Takehiro*; Shimomura, Takuya; Terada, Takaya; Daido, Hiroyuki
Journal of Laser Micro/Nanoengineering, 9(3), p.221 - 224, 2014/11
Times Cited Count：0 Percentile：0(Nanoscience & Nanotechnology)Heat resistant FBG sensors were developed by femtosecond laser processing to apply them to high temperature operated piping system of nuclear power plants. The FBG sensor was installed on the surface of a steel blade and a vibration test was conducted to detect the resonant vibration frequency of the vibrating blade. The FBG sensor had the heatproof performance at 600
C. A frequency stabilized sensing system using a tunable laser was tested for structural health monitoring in daily operation of nuclear power plants. The FBG sensor was installed on the surface of a steel blade for vibration induced strain measurements. Welding, brazing, soldering and noble metal powder adhesive were discussed for molding the FBG sensors.
Nishimura, Akihiko; Terada, Takaya; Takenaka, Yusuke*; Furuyama, Takehiro*; Shimomura, Takuya
Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 6 Pages, 2014/07
Since 2007, JAEA has been developing laser based technologies of structural health monitoring. The FBG sensor made by femtosecond laser processing will be the best candidate. To make the best use of the heat resistant characteristic, the FBG sensor was embedded in metal mold by laser cladding. A groove was processed to the surface of a SUS metal plate. We used a QCW laser to weld a filler wire on the plate. A series of weld beads perfectly formed a sealing clad on the groove. Though the FBG sensor was buried tightly, no degradation on the reflection spectrum was detected after the processing. The FBG sensor could detect the vibration of the plate caused by impact shocks and audio vibration. The reflection peak of the FBG sensor under laser cladding condition was shifted to be 6 nm. We demonstrated that the corresponded temperature derive from the reflection peak shift reached 600 degrees in heat shock experiments. The installation procedure of a FBG sensor using a portable laser cladding machine was described.
Sherrill, M. E.*; Abdallah, J. Jr.*; Csanak, G.*; Dodd, E. S.*; Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki*; Yamakawa, Koichi; et al.
Physical Review E, 73(6), p.066404_1 - 066404_6, 2006/06
Times Cited Count：29 Percentile：75.57(Physics, Fluids & Plasmas)A model that solves simultaneously both the electron and atomic kinetics was used to generate synthetic He
X-ray spectra to characterize a high intensity ultrashort laser driven Ar cluster target experiment. In particular, level populations were obtained from a detailed collisional-radiative model where collisional rates were computed from a time varying electron distribution function obtained from the solution of the zero dimensional Boltzmann equation. In addition, aparticle-in-cell simulation was used to model the laser interaction with the cluster target and provided the initial electron energy distribution function (EEDF) for the Boltzmann solver. This study suggests that the high density plasma contribution to the time-integrated He spectrum was in a highly non-equilibrium state in both the EEDF and the ion level populations and provides a prediction of 5.7 ps for the average cluster integrity time for this high density state.
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
Times Cited Count：3 Percentile：18.36(Optics)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.
Moribayashi, Kengo; Lee, K.*; Kagawa, Takashi*; Kim, D. E.*
Laser Physics, 16(2), p.322 - 324, 2006/02
Times Cited Count：1 Percentile：7.24(Optics)no abstracts in English
Moribayashi, Kengo; Kagawa, Takashi*; Kim, D. E.*
Journal of Physics B; Atomic, Molecular and Optical Physics, 38(13), p.2187 - 2194, 2005/07
Times Cited Count：6 Percentile：31.16(Optics)no abstracts in English
Kumada, Takayuki; Karavitis, M.*; Goldschleger, I. U.*; Apkarian, V. A.*
Hoshasen Kagaku, (79), p.30 - 35, 2005/03
We should know how the high energy deposited by irradiation dissipates in materials in order to understand radiation chemical processes. In this study, we carried out TR-CARS (Time-Resolved Coherent Anti-Stokes Raman Scattering) study of molecular iodine in solid krypton to understand the mechanism of vibrational relaxation in solid phase. Decoherence of the vibrational state is due to energy dissipation below 10 K whereas pure dephasing plays an important role above. We also found that the dephasing is due to the scattering with local phonon mode with the energy of 40 K.
(v = 1-19) in solid KrKaravitis, M.*; Kumada, Takayuki; Goldschleger, I. U.*; Apkarian, V. A.*
Physical Chemistry Chemical Physics, 7(5), p.791 - 796, 2005/02
Times Cited Count：30 Percentile：69.33(Chemistry, Physical)Energy dissipation and phase relaxation of the vibrational quantum states of iodine molecules in solid krypton have been studied in the temperature range between 7 and 45 K using a technique of time-resolved coherent anti-stokes Raman scattering (CARS) spectroscopy by a femto-second laser. The rate of energy dissipation was independent of tempeature, but proportional to the vibrational quantum number v. The pure dephasing rate exponentially increased with an increase in temperature and was proportional to v
. The energy relaxation was found to take place by transfering the vibrational energy of iodine to four phonons in the krypton solid. The pure dephasing was induced by elastic scattering with phonon. It was suggested by a computer simulation that the phonon which induced the pure dephasing accompanied libration mode of iodine molecules.
Moribayashi, Kengo; Kagawa, Takashi*; Kim, D. E.*
Journal of Physics B; Atomic, Molecular and Optical Physics, 37(20), p.4119 - 4126, 2004/10
Times Cited Count：12 Percentile：49.7(Optics)no abstracts in English
) and CaCO crystalsDeki, Kyoichi*; Matsuoka, Fumiaki*; Tei, Kazuyoku*; Arisawa, Takashi
Reza Kenkyu, 31(12), p.854 - 859, 2003/12
no abstracts in English
Daido, Hiroyuki
Reza Kenkyu, 31(11), p.696 - 697, 2003/11
no abstracts in English
Daido, Hiroyuki
Reza Kenkyu, 31(11), p.698 - 706, 2003/11
no abstracts in English
Yamakawa, Koichi; Aoyama, Makoto; Akahane, Yutaka; Ma, J.; Inoue, Norihiro*; Ueda, Hideki; Kiriyama, Hiromitsu
Reza Kenkyu, 30(12), p.747 - 748, 2002/12
no abstracts in English
Nagai, Ryoji; Hajima, Ryoichi; Sawamura, Masaru; Nishimori, Nobuyuki; Kikuzawa, Nobuhiro; Minehara, Eisuke
Proceedings of 27th Linear Accelerator Meeting in Japan, p.264 - 266, 2002/08
no abstracts in English
Nagai, Ryoji; Hajima, Ryoichi; Nishimori, Nobuyuki; Kikuzawa, Nobuhiro; Sawamura, Masaru; Minehara, Eisuke
Nuclear Instruments and Methods in Physics Research A, 483(1-2), p.129 - 133, 2002/05
Times Cited Count：7 Percentile：44.29(Instruments & Instrumentation)An intense ultrashort pulse is generated at the perfect synchronism of optical-resonator length in the JAERI far-infrared free-electron laser. At wavelength of 22.5 
m, second-order optical autocorrelation measurements show that the FEL pulse duration is 250 fs and less than four optical cycles which is consistent with numerical calculation result. The pulse energy ranges up to 100 J. The second-hermonic generation in a 2 mm thickness Te crystal is used to provide the nonlinear autocorrelation signal. In the various desynchronism of optical-resonator length, the way of appearing of the sub-pulse corresponded to the calculation result well, too.
Hajima, Ryoichi; Nishimori, Nobuyuki; Nagai, Ryoji; Minehara, Eisuke
Nuclear Instruments and Methods in Physics Research A, 483(1-2), p.113 - 118, 2002/05
Times Cited Count：8 Percentile：47.85(Instruments & Instrumentation)It has been verified experimentally in JAERI-FEL that a high-gain FEL oscillator has the maximum extraction efficiency at the perfect synchronism of optical-cavity length. The simultaneous measurement of FEL efficiency and absolute cavity length for various gain and loss parameters has clearly shown that the steep peak of detuning curve at the perfect synchronism appears only in high-gain and small-loss regime and the FEL extraction efficiency exceeds the scaling law of short-bunch FEL oscillators. A numerical analysis indicates that the lasing at the perfect synchronism is quasi-stationary superradiance with random fluctuation. It is also found that shot-noise in the electron bunch is inevitable to simulate the lasing at the perfect synchronism. Second-order autocorrelation measurements show that FEL pulses shorter than four optical cycles are successively generated for a number of round trips at the perfect synchronism, which is consistent with numerical results.
