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Journal Articles

Laser ablation absorption spectroscopy for isotopic analysis of plutonium; Spectroscopic properties and analytical performance

Miyabe, Masabumi; Oba, Masaki; Jung, K.; Iimura, Hideki; Akaoka, Katsuaki; Kato, Masaaki; Otobe, Haruyoshi; Khumaeni, A.*; Wakaida, Ikuo

Spectrochimica Acta, Part B, 134, p.42 - 51, 2017/08

 Times Cited Count:13 Percentile:13.95(Spectroscopy)

Spectroscopic properties of atomic species of plutonium were investigated by combining laser ablation and resonance absorption techniques for the analysis of a plutonium oxide sample. For 17 transitions of Pu atoms and ions, the absorbance, isotope shift, and hyperfine splitting were determined via Voigt profile fitting of the recorded absorption spectra. Three transitions were selected as candidates for analytical use. Using these transitions, we investigated the analytical performance that was attainable and determined a correlation coefficient R2 between the absorbance and plutonium concentration of 0.9999, a limit of detection of 30-130 ppm, and a relative standard deviation of approximately 6% for an abundance of $$^{240}$$Pu of 2.4%. These results demonstrate that laser ablation absorption spectroscopy is applicable to the remote isotopic analysis of highly radioactive nuclear fuels and waste materials containing multiple actinide elements.

Journal Articles

Dynamics of spallation during femtosecond laser ablation studied by time-resolved reflectivity with double pump pulses

Kumada, Takayuki; Otobe, Tomohito; Nishikino, Masaharu; Hasegawa, Noboru; Hayashi, Terutake*

Applied Physics Letters, 108(1), p.011102_1 - 011102_4, 2016/01


 Times Cited Count:8 Percentile:47.49(Physics, Applied)

The dynamics of photomechanical spallation during femtosecond laser ablation of fused silica was studied by time-resolved reflectivity with double pump pulses. Oscillation of reflectivity was caused by interference between the probe pulses reflected at the sample surface and the spallation layer, and was enhanced when the surface is irradiated with the second pump pulse within a time interval of several picoseconds after the first pump pulse. However, as the time-interval was increased, the oscillation amplitude decreased with an exponential decay time of 10 ps. The oscillation disappeared when the interval exceeded 20 ps. This result suggests that the formation time of the spallation layer is approximately 10 ps.

Journal Articles

The Observation of a transient surface morphology in the femtosecond laser ablation process by using the soft X-ray laser probe

Hasegawa, Noboru; Nishikino, Masaharu; Tomita, Takuro*; Onishi, Naofumi*; Ito, Atsushi*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Izutsu, Rui*; Minami, Yasuo*; Baba, Motoyoshi*; et al.

X-Ray Lasers and Coherent X-Ray Sources; Development and Applications XI (Proceedings of SPIE, Vol.9589), p.95890A_1 - 95890A_8, 2015/09

 Times Cited Count:1 Percentile:36.32

We have improved a soft X-ray laser (SXRL) interferometer synchronized with a Ti:Sapphire laser pulse to observe the single-shot imaging of the nano-scaled structure dynamics of the laser induced materials. By the precise imaging optics and double time fiducial system having been installed, the lateral resolution on the sample surface and the precision of the temporal synchronization between the SXRL and Ti:Sapphire laser pulses were improved to be 700 nm and 2 ps, respectively. By using this system, the initial stage (before 200 ps) of the ablation process of the Pt surface pumped by 80 fs Ti:Sapphire laser pulse was observed by the comparison between the soft X-ray reflective image and interferogram. We have succeeded in the direct observation of the unique ablation process around the ablation threshold such as the rapid increase of the surface roughness and surface vibration.

Journal Articles

Ablation plume structure and dynamics in ambient gas observed by laser-induced fluorescence imaging spectroscopy

Miyabe, Masabumi; Oba, Masaki; Iimura, Hideki; Akaoka, Katsuaki; Khumaeni, A.*; Kato, Masaaki; Wakaida, Ikuo

Spectrochimica Acta, Part B, 110, p.101 - 117, 2015/08


 Times Cited Count:16 Percentile:18.59(Spectroscopy)

The dynamic behavior of an ablation plume in ambient gas has been investigated by laser-induced fluorescence imaging spectroscopy. The second harmonic beam from an Nd:YAG laser (0.5-6J/cm$$^{2}$$) was focused on a sintered oxide pellet or a metal chip of gadolinium. The produced plume was subsequently intersected with a sheet-shaped UV beam from a dye laser so that time-resolved fluorescence images were acquired with an intensified CCD camera at various delay times. The obtained cross-sectional images of the plume indicate that the ablated ground state atoms and ions of gadolinium accumulate in a hemispherical contact layer between the plume and the ambient gas, and a cavity containing a smaller density of ablated species is formed near the center of the plume. At earlier expansion stage, another luminous component also expands in the cavity so that it coalesces into the hemispherical layer. The splitting and coalescence for atomic plume occur later than those for ionic plume. Furthermore, the hemispherical layer of neutral atoms appears later than that of ions; however, the locations of the layers are nearly identical. This coincidence of the appearance locations of the layers strongly suggests that the neutral atoms in the hemispherical layer are produced as a consequence of three-body recombination of ions through collisions with gas atoms. The obtained knowledge regarding plume expansion dynamics and detailed plume structure is useful for optimizing the experimental conditions for ablation-based spectroscopic analysis.

Journal Articles

Soft X-ray laser observation of femtosecond-laser-driven ablation of tungsten

Nishikino, Masaharu; Hasegawa, Noboru; Ishino, Masahiko; Ochi, Yoshihiro; Kawachi, Tetsuya; Yamagiwa, Mitsuru; Kato, Yoshiaki*

Chinese Optics Letters, 13(7), p.070002_1 - 070002_3, 2015/07

 Times Cited Count:1 Percentile:90.58(Optics)

Journal Articles

Observation of the dependence on the fluence and materials in femto-second laser ablation process by using the soft X-ray laser probe

Hasegawa, Noboru; Tomita, Takuro*; Nishikino, Masaharu; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Minami, Yasuo*; Baba, Motoyoshi*; Onishi, Naofumi*; Ito, Atsushi*; Kawachi, Tetsuya; et al.

JAEA-Conf 2015-001, p.17 - 20, 2015/07

We have succeeded in simultaneous observation of the ablation front and the expansion front with thin filmy structure in the femto-second laser ablation process of a gold target by using the 13.9 nm soft X-ray probe (incident angle to the sample $$sim$$ 70 deg) with soft X-ray interferometer. The dependence on the laser local fluence and materials was obtained by the comparison between gold and tungsten.

Journal Articles

Non-thermal effects on femtosecond laser ablation of polymers extracted from the oscillation of time-resolved reflectivity

Kumada, Takayuki; Akagi, Hiroshi; Itakura, Ryuji; Otobe, Tomohito; Nishikino, Masaharu; Yokoyama, Atsushi

Applied Physics Letters, 106(22), p.221605_1 - 221605_5, 2015/06

 Times Cited Count:3 Percentile:80.43(Physics, Applied)

The dynamics of femtosecond laser ablation of transparent polymers were examined using time-resolved reflectivity. When these polymers were irradiated by a pump pulse with fluence above the ablation threshold of 0.8-2.0 J/cm$$^{2}$$, we observed the oscillation of the reflectivity caused by the interference between the reflected probe pulses from the sample surface and the thin layer due to the non-thermal photomechanical effects of spallation. As the fluence of the pump pulse increased, the separation velocity of the thin layer increased from 6 km/s to an asymptotic value of 11 km/s. It is suggested that the velocities are determined by shock-wave velocities of the photo-excited layer.

Journal Articles

Observation of femtosecond laser ablation on Tungsten by using soft X-ray reflection and interference imaging

Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Onishi, Naofumi*; Ito, Atsushi*; Baba, Motoyoshi*; Minami, Yasuo*; Kawachi, Tetsuya; et al.

Reza Gakkai Dai-471-Kai Kenkyukai Hokoku; Tanhacho Ryoshi Bimu Hassei To Sono Oyo, p.9 - 12, 2014/12

no abstracts in English

Journal Articles

Surface nano-structuring produced by spallation of metal irradiated by an ultrashort laser pulse

Inogamov, N. A.*; Zhakhovsky, V. V.*; Ashitkov, S. I.*; Emirov, Y. N.*; Faenov, A. Y.*; Pikuz, T. A.*; Ishino, Masahiko; Kando, Masaki; Hasegawa, Noboru; Nishikino, Masaharu; et al.

Journal of Physics; Conference Series, 500(11), p.112070_1 - 112070_6, 2014/05

 Times Cited Count:18 Percentile:0.88

The mechanism of formation and geometry of surface structures are discussed for the case of single pulse acting on a well-polished metal surface. We demonstrate that the complex surface nano-structures are formed after laser irradiation due to the thermomechanical spallation of ultrathin surface layer of melt. Spallation is accompanied by a strong foaming of melt followed by breaking of the foam. After several nanoseconds the foam remnants freeze up with formation of complex nano-structures on a target surface.

Journal Articles

Spectroscopic study of reaction mechanism of laser-ablated silicon ions and neutrals with benzene molecules

Saeki, Morihisa; Oba, Hironori; Yokoyama, Atsushi

Journal of Physics; Conference Series, 59, p.732 - 735, 2007/00

 Times Cited Count:0 Percentile:100

We have performed laser ablation of silicon in neon gas and benzene vapor. The reaction mechanism of the ablated silicon atoms with the neon atoms and benzene molecules were investigated by space- and time-resolved emission spectroscopy. The ablation in the neon gas suggested that (1) the neutral neon atoms are excited to 2pn states lying in 18-19 eV and (2) the neutral neon atoms are excited by electronic-to-electronic and translational-to-electronic energy transfer from the silicon ions. In the ablation in the benzene vapor, we found that the benzene molecules are decomposed into C2 and CH radicals by the collision with the silicon atoms.

Journal Articles

Laser ablation of silicon in neon gas; Study of excitation mechanism of neon neutrals by ablated silicon ions

Saeki, Morihisa; Hirata, Koichi*; Sakka, Tetsuo*; Oba, Hironori; Yokoyama, Atsushi

Journal of Applied Physics, 98(4), p.044912_1 - 044912_6, 2005/08

 Times Cited Count:3 Percentile:85.27(Physics, Applied)

no abstracts in English

JAEA Reports

Basic study on ultra high sensitive neutron dosimetry technique based on resonant laser ablation, JAERI's nuclear research promotion program, H12-035 (Contract Research)

Iguchi, Tetsuo*; Watanabe, Kenichi*; Kawarabayashi, Jun*; Uritani, Akira*; Enokida, Yoichi*; Watanabe, Kazuo

JAERI-Tech 2004-010, 62 Pages, 2004/03


no abstracts in English

Journal Articles

Optical spectroscopy of plasma plume induced by pulsed laser deposition of TiO$$_{2}$$ thin films

Kitazawa, Shinichi; Yamamoto, Shunya

Transactions of the Materials Research Society of Japan, 28(4), p.1133 - 1136, 2003/12

The epitaxial growth of high quality TiO$$_{2}$$ films has attracted much interest from the viewpoints of basic science and applications. In the synthesis process of TiO$$_{2}$$ films, the pulsed laser deposition (PLD) method is widely employed because of its advantage for materials with high melting point. The laser irradiation generates plasmas from Ti bulk targets, and the evaporated Ti particles have interactions with buffer dioxide gas before/after the epitaxial growth. We observed the optical emission spectra from the plumes generated by laser ablation in order to improve on the epitaxial growth under proper conditions. The spectra show dependences of energy densities and wavelengths of the laser. The spectra are investigated for relevancies to the quality of films and crystallographic relationships that were assessed by x-ray diffraction, x-ray pole figures and Rutherford backscattering spectroscopy.

Journal Articles

Nanoparticle formation by pulsed laser ablation of TiO$$_{2}$$

Yamaki, Tetsuya; Ito, Hisayoshi; Matsubara, Masakazu*; Abe, Hiroaki*; Asai, Keisuke*

Transactions of the Materials Research Society of Japan, 28(3), p.879 - 882, 2003/10

Titanium oxide nanoparticles were formed by pulsed laser ablation of a TiO$$_{2}$$ rutile pellet with a KrF excimer laser ($$lambda$$ = 248 nm). The ablation was performed in atmospheres of Ar and O$$_{2}$$ at total pressures ranging from 0.2 and 10 Torr. At a higher pressure than 1 Torr, Ti in the nanoparticles had an oxidation state of 4+ to form TiO$$_{2}$$. According to the X-ray diffraction analyses, the nanopartiles were found to contain both the anatase and rutile phases, which crystallized through extremely energetic, non-equilibrium reactions in an ablation plume. In contrast, at pressures of 0.2 and 0.5 Torr, the nanoparticles were composed of dominant TiO$$_{2}$$ with a small amount of a less oxidized phase such as Ti$$_{2}$$O$$_{3}$$. The important result is that the XRD patterns of the samples prepared at 1 and 5 Torr showed the different anatase-to-rutile ratio of the peak intensities. This indicates that the weight fraction of the rutile/anatase crystalline phases can be controlled by the ambient gas pressure.

Journal Articles

Emission spectrum of the C$$_{2}$$ radical embedded in superfluid helium around 1.5 K

Wada, Akira; Aratono, Yasuyuki

Chemistry Letters, 32(2), p.200 - 201, 2003/02

 Times Cited Count:6 Percentile:68.49(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Time resolved measurement of laser-ablated particles by LAPXAS

Miyashita, Atsumi; Yoda, Osamu; *

Hyomen Kagaku, 20(3), p.180 - 185, 1999/00

no abstracts in English

Journal Articles

Forward-transfer laser implantation of pyrene molecules in a solid polymer

D.M.Karnakis*; Goto, Masahiro*; Ichinose, Yuji; Kawanishi, Shunichi; Fukumura, H.*

Applied Physics Letters, 73(10), p.1439 - 1441, 1998/09

 Times Cited Count:7 Percentile:62.45(Physics, Applied)

no abstracts in English

Journal Articles

Surface modification of polymer induced by laser

Suzuki, Nobutake; Kawanishi, Shunichi

Hoshasen Kagaku, 39(9), p.337 - 343, 1996/00

no abstracts in English

Journal Articles

Excimer laser irradiation effects on fluoropolymer and aromatic polymer

Kawanishi, Shunichi; Sugimoto, Shunichi; Shimizu, Yuichi; Suzuki, Nobutake

J. Photopolym. Sci. Technol., 5(2), p.271 - 278, 1992/00

no abstracts in English

Oral presentation

Photomechanical effects on femtosecond-laser ablation of fused silica studied using time-resolved reflectivity

Kumada, Takayuki; Akagi, Hiroshi; Itakura, Ryuji; Otobe, Tomohito; Yokoyama, Atsushi

no journal, , 

We observed oscillation of time-resolved reflectivity of femtosecond-laser-ablated fused silica. We ascribe the oscillation to the interference between probe pulses reflected from a sample surface and a thin layer produced by the photomechanical effect.

50 (Records 1-20 displayed on this page)