Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Kiichiro Uchino Last modified date:2019.06.29

Professor / Electrical Engineering Sciences / Department of Advanced Energy Science and Engineering / Faculty of Engineering Sciences


Papers
1. H. Kajiyama, S. Kuboyama, A. Otomo, H. Uyama, T. Matsuura, S. Inoue, Y. Matsumura, K. Takata, K. Tomita, K. Uchino, VHF Plasma CVD Synthesis of Photochromic ZnO Nanoparticle, MRS advances, https://doi.org/10.1557/adv.2019.80, Volume 4, Issue 27 2019 , pp. 1573-1577, 2019.02.
2. K. Bajo, O. Fujioka, S. Itose, M. Ishihara, K. Uchino, H. Yurimoto, Electronic data acquisition and operational control system for time-of-flight sputtered neutral mass spectrometer, Surface and Interface Analysis, 10.1002/ sia.6541, 2018.09.
3. Li Wen Su, Weiting Chen, Kiichiro Uchino, Yoshinobu Kawai, Two dimensional simulations of triode VHF SiH4 plasma , Japanese Journal of Applied Physics, 10.7567/JJAP.57.06JG01, 57, 2018.06.
4. Li Wen Su, Weiting Chen, Kiichiro Uchino, Yoshinobu Kawai, Two-dimensional simulations of multi-hollow VHF SiH4/H2 plasma, AIP Advances, 10.1063/1.5003911, 8, 2, 2018.02, A triode multi-hollow VHF SiH4/H2 plasma (60 MHz) was examined at a pressure of 20 Pa by two-dimensional simulations using the fluid model. In this study, we considered the effect of the rate constant of reaction, SiH3 + SiH3→SiH2 + SiH4, on the plasma characteristics. A typical VHF plasma of a high-electron density with a low-electron temperature was obtained between two discharge electrodes. Spatial profiles of SiH3 +, SiH2 +, SiH3 - and SiH3 densities were similar to that of the electron density while the electron temperature had a maximum value near the two discharge electrodes. It was found that the SiH3 radical density did not decrease rapidly near the substrate and the electron temperature was lower than 1 eV, suggesting that the triode multi-hollow plasma source can provide high quality amorphous silicon with a high deposition rate..
5. Kentaro Tomita, Yuta Sato, Syouichi Tsukiyama, Toshiaki Eguchi, Kiichiro Uchino, Kouichiro Kouge, Hiroaki Tomuro, Tatsuya Yanagida, Yasunori Wada, Masahito Kunishima, Georg Soumagne, Takeshi Kodama, Hakaru Mizoguchi, Atsushi Sunahara, Katsunobu Nishihara, Time-resolved two-dimensional profiles of electron density and temperature of laser-produced tin plasmas for extreme-ultraviolet lithography light sources, Scientific Reports, 10.1038/s41598-017-11685-0, 7, 1, 2017.12, Time-resolved two-dimensional (2D) profiles of electron density (n e) and electron temperature (T e) of extreme ultraviolet (EUV) lithography light source plasmas were obtained from the ion components of collective Thomson scattering (CTS) spectra. The highest EUV conversion efficiency (CE) of 4% from double pulse lasers irradiating a Sn droplet was obtained by changing their delay time. The 2D-CTS results clarified that for the highest CE condition, a hollow-like density profile was formed, i.e., the high density region existed not on the central axis but in a part with a certain radius. The 2D profile of the in-band EUV emissivity (ηEUV) was theoretically calculated using the CTS results and atomic model (Hullac code), which reproduced a directly measured EUV image reasonably well. The CTS results strongly indicated the necessity of optimizing 2D plasma profiles to improve the CE in the future..
6. Y. Sakawa, T. Ide, Taichi Morita, Kentaro Tomita, Kiichiro Uchino, Y. Kuramitsu, N. Ohnishi, H. Takabe, Generation of counter-streaming plasmas for collisionless shock experiment, High Energy Density Physics, 10.1016/j.hedp.2017.04.007, 23, 207-211, 2017.06, The generation mechanism of counter-streaming plasmas, by irradiating an inner-surface of the 1st-plane of double-plane target, is investigated experimentally using optical imaging and collective Thomson scattering (CTS) ion-term measurement. The CTS measurement reveals that counter-streaming plasmas exist at the same time at the same position, which is the evidence for the collisionless interaction between the counter-streaming plasmas. The generation of the 2nd-plane plasma is in two steps: First, the 2nd-plane is ablated nearly at the laser timing by radiation from the 1st-plane plasma. Then ≃ 5−7ns later, when the plasma from the 1st-plane reaches the 2ns-plane, it induces higher-density plasma generation..
7. N. Khasanah, C. W. Peng, C. H. Chen, T. Y. Huang, N. Bolouki, T. Moritaka, Y. Hara, H. Shimogawara, T. Sano, Y. Sakawa, Y. Sato, Kentaro Tomita, Kiichiro Uchino, Shuichi Matsukiyo, Y. Shoji, S. Tomita, S. Tomiya, R. Yamazaki, M. Koenig, Y. Kuramitsu, Spatial and temporal plasma evolutions of magnetic reconnection in laser produced plasmas, High Energy Density Physics, 10.1016/j.hedp.2017.02.004, 23, 15-19, 2017.06, Magnetic reconnection is experimentally investigated in laser produced plasmas. By irradiating a solid target with a high-power laser beam, a magnetic bubble is generated due to the Biermann effect. When two laser beams with finite focal spot displacements are utilized, two magnetic bubbles are generated, and the magnetic reconnection can take place. We measure the spatial and temporal plasma evolutions with optical diagnostics using framing camera. We observed the plasma jets, which are considered to be reconnection out flows. Spatial and temporal scales of the plasma jets are much larger than those of laser. The magnetic reconnection time has been estimated from the expansion velocity, which is consistent with the Sweet-Parker model..
8. Yuta Sato, Kentaro Tomita, Syoichi Tsukiyama, Toshiaki Eguchi, Kiichiro Uchino, Kouichiro Kouge, Hiroaki Tomuro, Tatsuya Yanagida, Yasunori Wada, Masahito Kunishima, Takeshi Kodama, Hakaru Mizoguchi, Spatial profiles of electron density, electron temperature, average ionic charge, and EUV emission of laser-produced Sn plasmas for EUV lithography, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.7567/JJAP.56.036201, 56, 3, 2017.03, Spatial profiles of the electron density (ne), electron temperature (Te), and average ionic charge (Z) of laser-produced Sn plasmas for EUV lithography, whose conversion efficiency (CE) is sufficiently high for practical use, were measured using a collective Thomson scattering (TS) technique. For plasma production, Sn droplets of 26μm diameter were used as a fuel. First, a picosecond-pulsed laser was used to expand a Sn target. Next, a CO2 laser was used to generate plasmas. By changing the injection timing of the picosecond and CO2 lasers, three different types of plasmas were generated. The CEs of the three types of plasmas differed, and ranged from 2.8 to 4.0%. Regarding the different plasma conditions, the spatial profiles of ne, Te, and Z clearly differed. However, under all plasma conditions, intense EUV was only observed at a sufficiently high Te (> 25 eV) and in an adequate ne range [1024-(2 × 1025)m-3]. These plasma parameters lie in the efficient-EUV light source range, as predicted by simulations..
9. Masataka Iwamoto, Naoji Yamamoto, Taichi Morita, Hideki Nakashima, Kentaro Tomita, Kiichiro Uchino, Rayleigh scattering measurement of neutral atom number density downstream of a hall thruster under cold flow conditions, Transactions of the Japan Society for Aeronautical and Space Sciences, 10.2322/tjsass.60.327, 60, 5, 327-330, 2017.01, The approach presented in a study uses the laser Rayleigh scattering technique. This is a non-intrusive method, and it does not disturb the plasma and neutral flow. Number densities can be measured quantitatively by calibration using 104 Pa nitrogen, so a complicated collisional-radiative model is not required. The Rayleigh scattering spectrum reflects the velocity distribution of the atoms, so propellant xenon atoms can be distinguished from the ambient xenon atoms. In addition, even when both ions and electrons are present, the neutral number density can be estimated, since the scattering spectrum is a convolution of Rayleigh and Thomson spectra..
10. Kuan Chen Chen, Kuo Feng Chiu, Kohei Ogiwara, Li Wen Su, Kiichiro Uchino, Yoshinobu Kawai, Study of spatial profiles of capacitively coupled VHF H2 plasma by simulation, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.7567/JJAP.56.01AC05, 56, 1, 2017.01, The spatial profiles of a VHF H2 plasma (60MHz) for different discharge gap distances were examined at pressures of 66.7 and 133.3 Pa by twodimensional simulations using the plasma hybrid code. The electron density had a peak profile, and the maximum density depended on both the discharge gap distance and the pressure. A high-electron-density plasma with a low-electron temperature of approximately 1 eV was predicted by simulation at discharge gap distances of 15 and 20 mm. The plasma potential profile was composed of a plateau at the center and sharp slopes at the two sides. The axial profiles of the H+, H2+, and H3+ densities were calculated for the discharge gap distances of 10, 15, and 20 mm. It was found that the dominant ion species was H3+ except near the discharge electrode and the H2+ density near the discharge electrode was not negligible compared with the H3+ density at 66.7 Pa..
11. Azusa Tonotani, Ken ichi Bajo, Satoru Itose, Morio Ishihara, Kiichiro Uchino, Hisayoshi Yurimoto, Evaluation of multi-turn time-of-flight mass spectrum of laser ionization mass nanoscope, Surface and Interface Analysis, 10.1002/sia.6112, 48, 11, 1122-1126, 2016.11, We have evaluated the performance of a multi-turn time-of-flight mass spectrometer (MULTUM II) equipped with the ion injection optics of a laser ionization mass nanoscope (LIMAS). We surveyed the optimal parameters for the ion injection optics, which consist of ion extraction from a sample surface and ion introduction into MULTUM II. We developed mass calibration methods for correcting the modulation of load voltage for MULTUM II and injection timing for the ion injection optics. As a result, the mass-resolving power of LIMAS increased linearly with increasing the flight path length, and reached 6.2 × 105 (full width at half maximum) at 1000 multi-turn cycles of MULTUM II (flight path length: 1.3 km). The transmittance of LIMAS decreased to 60–70% after 20 multi-turn cycles of MULTUM II, compared with the linear mode transmittance. The transmittance per multi-turn cycle became constant (99.96%) after 20 multi-turn cycles. A useful yield of 3 × 10−3 for Si ions was obtained for LIMAS at 30 multi-turn cycles of MULTUM II..
12. Ken ichi Bajo, Satoru Itose, Miyuki Matsuya, Morio Ishihara, Kiichiro Uchino, Masato Kudo, Isao Sakaguchi, Hisayoshi Yurimoto, High spatial resolution imaging of helium isotope by TOF-SNMS, Surface and Interface Analysis, 10.1002/sia.6085, 48, 11, 1190-1193, 2016.11, Laser ionization mass nanoscope is a time-of-flight sputtered neutral mass spectrometer associated with laser post-ionization by tunneling effect. A spherical and chromatic aberration corrector is installed in the primary ion column. The lateral spatial resolving power of He imaging of solid surface has been evaluated by scanning image using a probe diameter of 90 nm from crater edge slope of a He ion-implanted Si substrate. Helium distribution from the scanning image is quantitatively equivalent with depth profiling analysis from surface of the same substrate, indicating that spatial resolving power of 20 nm for depth resolution has been achieved on the He scanning image through use of oblique incident effect of the primary beam..
13. Hisayoshi Yurimoto, Ken ichi Bajo, Isao Sakaguchi, Taku T. Suzuki, Amy J.G. Jurewicz, Satoru Itose, Kiichiro Uchino, Morio Ishihara, Quantitative analysis of helium by post-ionization method using femtosecond laser technique, Surface and Interface Analysis, 10.1002/sia.6119, 48, 11, 1181-1184, 2016.11, Helium has the largest ionization potential of all elements; thus, it is difficult to ionize for measurement by mass spectrometry. In order to analyze He, a tunnel-ionization time-of-flight sputtered neutral mass spectrometry system (called LIMAS) has recently been developed. LIMAS uses a femtosecond laser technique and can ionize He. We quantified the effectiveness of this method for He analysis from a 2.5 × 4 µm2 area of He-implanted silicon. The amount of He in an implant was quantified by measuring the ion current, giving a nominal implant fluence per unit area. Thus, the fraction of total He measured by LIMAS during depth profiling could be quantified by comparison with the He concentration of the reference implant. The He+ intensities normalized by host ions of Si linearly correlated with the known He concentrations with a reproducibility of 10% at concentrations less than 1021 cm−3. The detection limit was down to 1018 He cm−3 (20 ppm). For concentrations exceeding 1021 cm−3, the He intensities are smaller than those expected from the lower concentration range. This non-linearity may reflect the limit of retention of He in the Si lattice, because He is chemically inert..
14. Kentaro Tomita, Keiichiro Urabe, Naoki Shirai, Yuta Sato, Safwat Hassaballa, Nima Bolouki, Munehiro Yoneda, Takahiro Shimizu, Kiichiro Uchino, Electron density change of atmospheric-pressure plasmas in helium flow depending on the oxygen/nitrogen ratio of the surrounding atmosphere, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.7567/JJAP.55.066101, 55, 6, 2016.06, Laser Thomson scattering was applied to an atmospheric-pressure plasma produced in a helium (He) gas flow for measuring the spatial profiles of electron density (ne) and electron temperature (Te). Aside from the He core flow, the shielding gas flow of N2 or synthesized air (N2 : O2 = 4 : 1) surrounding the He flow was introduced to evaluate the effect of ambient gas components on the plasma parameters, eliminating the effect of ambient humidity. The ne at the discharge center was 2.7 ' 1021m%3 for plasma generated with N2/O2 shielding gas, 50% higher than that generated with N2 shielding..
15. Kuan Chen Chen, Kuo Feng Chiu, Chia Fu Chen, Cheng Yang Lien, Yu Jer Tsai, Ting Kuei Lien, Fumihiko Matsunaga, Masaaki Tanaka, Kohei Ogiwara, Kiichiro Uchino, Yoshinobu Kawai, Observation of Bi-Maxwellian Distributions in a H2 Plasma Produced by a Narrow Gap VHF Discharge, Plasma Processes and Polymers, 10.1002/ppap.201500183, 13, 6, 584-587, 2016.06, A capacitively coupled VHF H2 plasma (60 MHz) was produced by a narrow gap discharge at high pressures, and spatial distributions of the plasma parameters were examined with the Langmuir probe. A bi-Maxwellian electron distribution was observed near the discharge electrode while a Maxwellian one near the center of the inter-electrode gap. The simulation using the PIC code showed that electrons had the Druyvesteyn-like distribution near the discharge electrode..
16. Shuhei Inoue, Takahiro Kawamoto, Yukihiko Matsumura, Kentaro Tomita, Kiichiro Uchino, Keiji Takata, Hiroshi Kajiyama, Synthesis of photochromic nanoparticles and determination of the mechanism of photochromism, AIP Advances, 10.1063/1.4952424, 6, 5, 2016.05, Photochromic nanoparticles of zinc-silicon oxide were synthesized using plasma enhanced chemical vapor deposition. These particles turned black upon irradiating with ultraviolet light. We investigated this phenomenon using density functional theory calculations. Silicon inclusions create trap levels and oxygen defects that reduce the ionization potential of ZnO. This forms a quantum potential between ZnO and zinc-silicon oxide, and the excited electron is stable. Because oxygen defects also increase the bond overlap population between the zinc atoms in a ZnO crystal, they introduce further defects and help in the formation of quantum potentials. Growth of a perfect crystal of ZnO prevents the formation of oxygen defects, which is not desirable for photochromism..
17. T. Ishikawa, Y. Sakawa, Taichi Morita, Y. Yamaura, Y. Kuramitsu, T. Moritaka, T. Sano, R. Shimoda, Kentaro Tomita, Kiichiro Uchino, Shuichi Matsukiyo, A. Mizuta, N. Ohnishi, R. Crowston, N. Woolsey, H. Doyle, G. Gregori, M. Koenig, C. Michaut, A. Pelka, D. Yuan, Y. Li, K. Zhang, J. Zhong, F. Wang, H. Takabe, Thomson scattering measurement of a collimated plasma jet generated by a high-power laser system, Journal of Physics: Conference Series, 10.1088/1742-6596/688/1/012098, 688, 1, 2016.04, One of the important and interesting problems in astrophysics and plasma physics is collimation of plasma jets. The collimation mechanism, which causes a plasma flow to propagate a long distance, has not been understood in detail. We have been investigating a model experiment to simulate astrophysical plasma jets with an external magnetic field [Nishio et al., EPJ. Web of Conferences 59, 15005 (2013)]. The experiment was performed by using Gekko XII HIPER laser system at Institute of Laser Engineering, Osaka University. We shot CH plane targets (3 mm × 3 mm × 10 μm) and observed rear-side plasma flows. A collimated plasma flow or plasma jet was generated by separating focal spots of laser beams. In this report, we measured plasma jet structure without an external magnetic field with shadowgraphy, and simultaneously measured the local parameters of the plasma jet, i.e., electron density, electron and ion temperatures, charge state, and drift velocity, with collective Thomson scattering..
18. Y Kuramitsu, S. Matsukiyo, Youichi Sakawa, Taichi Morita, Y Yamaura, T Ishikawa, T Moritaka, T Sano, Kentaro Tomita, Ryo Shimoda, Yuta Sato, Kiichiro Uchino, Hideaki Takabe, Spherical shock in the presence of an external magnetic field, Journal of Physics: Conference Series, 10.1088/1742-6596/688/1/012056, 688, 012056, 2016.03.
19. T Ishikawa, Youichi Sakawa, Taichi Morita, Y Yamaura, T Moritaka, T Sano, Ryo Shimoda, Kentaro Tomita, Kiichiro Uchino, S. Matsukiyo, Hideaki Takabe, Thomson scattering measurement of a collimated plasma jet generated by a high-power laser system, Journal of Physics: Conference Series, 10.1088/1742-6596/688/1/012098, 688, 012056, 2016.03.
20. Kuan-Chen Chen, Chia-Fu Chen, Cheng-Yang Lien, Kuo-Feng Chiu, Kohei Ogiwara, Kiichiro Uchino, Yoshinobu Kawai, Axial distribution of a VHF H2 plasma produced by a narrow gap discharge, Japanese Journal of Applied Physics, 55, 1S, 01AH01, 2016.01.
21. Kuan-Chen Chen, Kuo-Feng Chiu, Chia-Fu Chen, Cheng-Yang Lien, Yu-Jer Tsai, Ting-Kuei Lien, Fumihiko Matsunaga, Masaaki Tanaka, Kohei Ogiwara, Kiichiro Uchino, Yoshinobu Kawai, Observation of Bi-Maxwellian Distributions in a H2 Plasma Produced by a Narrow Gap VHF Discharge, Plasma Processes and Polymers, 10.1002/ppap.201500183, 2015.12.
22. Kentaro Tomita, Yuta Sato, Kazutaka Nishikawa, Kiichiro Uchino, Tatsuya Yanagida, Hiroaki Tomuro, Yasunori Wada, Masahito Kunishima, Takeshi Kodama, Hakaru Mizoguchi, Atsushi Sunahara, Development of a collective Thomson scattering system for laser-produced tin plasmas for extreme-ultraviolet light sources, Applied Physics Express, 10.1002/ppap.201500183, 8, 12, 126101, 2015.11.
23. Ken-ichi Bajo, Chad T. Olimnger, Amy J. G. Jurewicz, Donald S. Burnett, Isao Sakaguchi, Taku Suzuki, Satoru Itose, Morio Ishihara, Kiichiro Uchino, Rainer Wieler, Hisayoshi Yurimoto, Depth profiling analysis of solar wind helium collected in diamond-like carbon film from Genesis, Geochemical Journal, 10.2343/geochemj.2.0385, 49, 5, 559-556, 2015.09.
24. KENTARO TOMITA, D. Gojima, K. Nagai, T. Shimizu, Kiichiro Uchino, T. Nakano, Y.Tanaka, K.Suzuki, T.Iijima, T.Uchii, T.Shinkai, Thomson scattering diagnostics of SF6 gas-blasted arcs confined by a nozzle under free-recovery conditions, Vol.48, 265201 (14 pages), 2015.07.
25. Nima Bolouki, S. Hassaballa, KENTARO TOMITA, Kiichiro Uchino, Development of Thomson Scattering Diagnostics for Cathode-Directed Streamer Discharges in Helium, Vol. 36 (2), pp. 1-5 (2015), 2015.02.
26. Nima Bolouki, KENTARO TOMITA, S. Hassaballa, Yukihiko Yamagata, Kiichiro Uchino, Temporal evolution of electron density and electron temperature profiles in a non-thermal atmospheric-pressure plasma measured by laser Thomson scattering, Vol. 54 (1), 016101 (4 pages), 2015.01.
27. Kohei Ogiwara, Weitin Chen, Kiichiro Uchino, Yoshinobu Kawai, Simulation of balanced power feeding plasma surrounded by a metal box, Vol. 54, No. 1S, 01AC04, 2015.01.
28. X. Wang, Atsushi Mase, M. Inutake, Y. Kogi, Kiichiro Uchino, Synthetic aperture radar using ultra-wideband microwave-modulated laser, J. Electromagnetic Waves and Applications, Vol. 28, Issue 11, pp. 1275-1281., 2014.11.
29. T. Yamane, S. Nakao, Y. Takeuchi, R. Ichiki, H. Muta, Kiichiro Uchino, Yoshinobu Kawai, Estimation of negative ions in VHF SiH4/H2 plasma, Vol. 53, No. 11, 116101, 2014.11.
30. KENTARO TOMITA, Y. Yoshitake, Kiichiro Uchino, D. Takenaga, H. Toda, H. Hikita, K. Suzuki, Measurements of Electron Density and Electron Temperature of Arc Discharge Plasmas Containing Metallic Vapors Using Laser Thomson Scattering, 188, 4, 1-8, 2014.09.
31. KENTARO TOMITA, D. Gojima, K. Nagai, T. Shimizu, Kiichiro Uchino, Y.Tanaka, K.Suzuki, T.Iijima, T.Uchii, T.Shinkai, Optical Diagnostics of Decay Processes of Ar/SF6 Gas Blast Arcs Confined by a Nozzle, Int. Conf. Gas Discharges and Their Appl. GD2014,, A36, pp.187-190, 2014.6, 2014.06.
32. Jing Ying Zhang, R. Ichiki, Kiichiro Uchino, Yoshinobu Kawai, Characteristics of Floating Potential in Negative Ion Plasma, Vol. 11, Issue 6, pp. 545–550, 2014.06.
33. KENTARO TOMITA, K. Nagai, T. Shimizu, Nima Bolouki, Yukihiko Yamagata, Kiichiro Uchino, T. Kaneko, Thomson scattering diagnostics of atmospheric plasmas in contact with ionic liquids, Vol. 7, No. 6, 066101 (4 pages), 2014.06.
34. M. Ikeda, Atsushi Mase, Kiichiro Uchino, Small Conductive Particle Detection with a Microwave Resonant Cavity, Electrical Engineering in Japan, Vol. 186, Issue 2,pp. 61–67, 2014.01.
35. KENTARO TOMITA, Daisuke Gojima, Kazuhiko Nagai, Kiichiro Uchino, Yasunori Tanaka, Katsumi Suzuki, Toshiyuki Uchii, Thomson scattering diagnostics of decay processes of Ar/SF6 gas-blast arcs confined by a nozzle, J. Phys. D: Appl. Phys., Vol. 46, 382001 (5 pages), 2013.09.
36. Taichi Morita, Yoichi Sakawa, KENTARO TOMITA, Kunio Tsubouchi, Kiichiro Uchino, Hideaki Takabe, Thomson scattering measurements of a shock in laser-produced counter-streaming plasmas, Phys. Plasmas, Vol. 20, 092115 (6 pages), 2013.09.
37. Weitin Chen, Kohei Ogiwara, Koichiro Koge, 富田 健太郎, 内野 喜一郎, 河合 良信, Investigation of VHF argon plasma at high pressure by balanced power feeding using laser Thomson scattering, Engineering Sciences Reports, Kyushu University, Vol. 35, No. 1, pp. 6-11, 2013.09.
38. T. Yamane, S. Nakao, Y. Takeuchi, H. Muta, R. Ichiki, Kiichiro Uchino, Yoshinobu Kawai, Measurements of SiH4/H2 VHF Plasma Parameters with Heated Langmuir Probe, Contrib. Plasma Phys., Vol. 53, No. 8, pp. 588-591, 2013.08.
39. Weitin Chen, Kohei Ogiwara, Koichiro Koge, KENTARO TOMITA, Kiichiro Uchino, Yoshinobu Kawai, Diagnostics of VHF argon plasmas by laser Thomson scattering, Plasma and Fusion Research, Vol. 8, 1306114 (4 pages), 2013.08.
40. T. Ishihara, T. Hori, K. Kakizaki, Kiichiro Uchino, ArF Excimer Laser Operated at 10 kHz for Small Electrode Separations, レーザー研究, Vol. 41, No. 7, pp. 517-521, 2013.07.
41. KENTARO TOMITA, Kazuki Nakayama, Kazuya Inoue, Atsushi Sunahara, Kiichiro Uchino, A collective laser Thomson scattering system for diagnostics of laser-produced plasmas for extreme ultraviolet light sources, Appl. Phys. Express, Vol. 6, 076101 (4 pages), 2013.06.
42. M. Ikeda, M. Ignatenko, Atsushi Mase, Kiichiro Uchino, Modeling and experimental detection of resonance frequency shift of a microwave cavity caused by a small conductive particle, J. Electromagnetic Waves and Applications, Vol. 27, pp. 1114-1126, 2013.05.
43. Shingo Ebata, Morio Ishihara, Kousuke Kumondai, Ryo Mibuka, Kiichiro Uchino, Hisayoshi Yurimoto, Development of an Ultra-High Performance Multi-Turn TOF-SIMS/SNMS System "MULTUM-SIMS/SNMS", Journal of the American Society for Mass Spectrometry, 24, 2, 222-229, 2013.02.
44. Yoshinobu Kawai, Kiichiro Uchino, Hiroshi Muta, Tobias Röwf, Development of a 915 MHz ECR plasma source, Vacuum, 87, 123-127, 2013.01.
45. Naoji Yamamoto, KENTARO TOMITA, Kensaku Sugita, Tomoaki Kurita, Hideki Nakashima, Kiichiro Uchino, Measurement of xenon plasma properties in an ion thruster using laser Thomson scattering technique, Review of Scientific Instruments, 83, 7, 073106, 2012.07.
46. Shingo Ebata, Morio Ishihara, Kiichiro Uchino, Satoru Itose, Miyuki Matsuya, Masato Kudo, Ken-ichi Bajo, Hisayoshi Yurimoto, Development of laser ionization mass nanoscope (LIMAS), Surface and Interface Analysis, DOI: 10.1002/sia.4857, 44, 6, 635-640, 2012.06.
47. Kentaro Tomita, Nima Bolouki, Hiroki Shirozono, Yukihiko Yamagata, Kiichiro Uchinoa, Koichi Takaki, Two-dimensional Thomson scattering diagnostics of pulsed discharges produced at atmospheric pressure, Journal of Instrumentation, Vol. 7, C02057(11pages), 2012.02.
48. Tatsuyuki Nishimiya, Tsukasa Yamane, Sachiko Nakao, Yoshiaki Takeuchi, Yasuhiro Yamauchi, Hiromu Takatsuka, Hiroshi Muta, Kiichiro Uchino, Yoshinobu Kawai , Characteristics of SiH4/H2 VHF plasma produced by short gap discharge
, Surface and Coatings Technology, Vol. 205, pp. S411-S414, 2011.06.
49. Tatsuyuki Nishimiya , Tsukasa Yamane , Yoshiaki Takeuchi , Yasuhiro Yamauchi, Hiromu Takatsuka ,Hiroshi Muta , Kiichiro Uchino , Yoshinobu Kawai, Control of large area VHF plasma produced at high pressure, Thin Solid Films, Vol. 519, pp. 6931-6934, 2011.06.
50. Hiroshi Muta, Satoshi Nishida, Shizuma Kuribayashi, Naoki Yoshikawa, Ryota Komatsu, Kiichiro Uchino, and Yoshinobu Kawai, Effect of Excitation Frequency on the Spatial Distributions of a Surface Wave Plasma, Japanese Journal of Applied Physics (PART 2), 50, 1, art. no. 01AB07, 2011.01.
51. Nima Bolouki, Kentaro Tomita, Yukihiko Yamagata, Kiichiro Uchino, Development of a Laser Thomson Scattering Diagnostics System for Dielectric Barrier Discharge Plasmas, Proceedings of the 63rd gaseous electronic conference and 7th international conference on reactive plasmas (Paris, France, 10/4-8, 2010), TF3-007, 2010.10.
52. Kentaro Tomita, Kota Ohara, Kazuki Nakayama, Kiichiro Uchino, Development of a Collective Thomson Scattering System for Diagnostics of Laser Produced EUV Plasmas, Proceedings of the 63rd gaseous electronic conference and 7th international conference on reactive plasmas (Paris, France, 10/4-8, 2010), DTP-167, 2010.10.
53. Y. Yamagata, M. Kai, S. Naito, K. Kamio, Y. Manabe, K. Uchino, Gas dependency of electrode temperature and emission of emitter material in a low-pressure fluorescent lamp, Proceedings of the 12th International Symposium on the Science and Technology of Light Sources (Eindhoven, the Netherlands, July 11-16, 2010), pp. 527-528, 2010.07.
54. N. Yamamoto, K. Tomita, N. Yamasaki, T. Tsuru, T. Ezaki, Y. Kotani, K. Uchino, H. Nakashima, Measurements of electron density and temperature in a miniature microwave discharge ion thruster using laser Thomson scattering technique
, Plasma Sources Science and Technology, 19, 45009, 2010.06.
55. Y. Kawai, K. Uchino, H. Muta, S. Kawai, T. Rowf, Development of large diameter ECR plasma source, Vacuum, 84, 13811384, 2010.06.
56. Yukihiko Yamagata, Makoto Kai, Sho Naito, Kentaro Tomita, Kiichiro Uchino, Yoshio Manabe, Relationship between Ba atom emission and electrode temperature in a low-pressure fluorescent lamp, THIN SOLID FILMS, Vol. 518, No. 13, Sp. Iss. SI, pp. 3449-3452, 2010.04.
57. Tomita Kentaro, Yamamoto Naoji, Yamasaki Naoto, Tsuru Teppei, Uchino Kiichiro, and Nakashima Hideki, Thomson-Scattering Diagnostics of Plasmas Produced in a Miniature Microwave Discharge Ion Engine, JOURNAL OF PROPULSION AND POWER, Vol. 26, No. 2, pp. 381-384, 2010.04.
58. Y. Yamauchi, T. Baba, T. Yamane, Y. Takeuchi, H. Takatsuka, H. Muta, K. Uchino, Y. Kawai, Dominant Ion Species in VHF SiH4/H2 Plasma, Physica Status Solidi C, 7, 3月4日, 549-552, 2010.04.
59. Kentaro Tomita, Yukihiko Yamagata, Kiichiro Uchino, Development of a Laser Thomson Scattering System for Pulsed Filament Discharges Produced in Near-Atmospheric Pressure, Proceedings of the 31st International Symposium on Dry Process (Busan, Korea, 9/24-25, 2009), pp.165-166, 2009.09.
60. Yukihiko Yamagata, Makoto Kai, Susumu Naito, Masaru Naka, Kentaro Tomita, Kiichiro Uchino, Yoshio Manabe, Ba atom emission and electrode temperature distribution in a low-pressure fluorescent lamp, Proceedings of the 19th International Symposium on Plasma Chemistry (Bochum, Germany, 7/26-31, 2009), P.2.2.28, pp.1-4 , 2009.07.
61. Kiichiro Uchino, Kentaro Tomita, Yukihiko Yamagata, Diagnostics of a pulsed filament discharge using laser Thomson scattering, Proceedings of the 19th International Symposium on Plasma Chemistry (Bochum, Germany, 7/26-31, 2009), P.2.2.26, pp.1-4, 2009.07.
62. Y. Sonoda, S. Nishimoto, K. Tomita, S. Hassaballa, Y. Yamagata, K. Uchino, Laser Thomson Scattering Diagnostics of Dielectric Barrier Discharge Plasmas, J. Plasma Fusion Res. Series, Vol. 8, pp. 696-699, 2009.06.
63. K. Tomita, T. Kagawa, K. Uchino, S. Katsuki, H. Akiyama, Collective Thomson Scattering Diagnostics of EUV Plasmas, J. Plasma Fusion Res. Series, Vol. 8, pp. 488-491, 2009.06.
64. Y. Yamauchi, T. Baba, Y. Takeuchi, H. Takatsuka, H. Muta, K. Uchino, Y. Kawai, Development of VHF Plasma Source with Short Discharge Gap for Solar Cells, Plasma Processes and Polymers, Vol. 6, pp. S273-S277, 2009.06.
65. Toru Ezaki, Kentaro Tomita, Yusuke Kotani, Naoji Yamamoto, Naoto Yamasaki, Teppei Tsuru, Kiichiro Uchino, Hideki Nakashima, Dependence of Electron Temperature and Number Density on Magnetic Field Strength in an Ion Thruster by Laser Thomson Scattering, Journal of Applied Plasma Science, 17, 1, 21-26, 2009.06.
66. Masaru Naka, Yuichi Egashira, Kentaro Tomita, Yukihiko Yamagata, Kiichiro Uchino, Y. Manabe, T. Ueda, MEASUREMENTS OF DISTRIBUTIONS OF Ba ATOM DENSITY AND ELECTRODE TEMPERATURE IN LOW-PRESSURE FLUORESCENT LAMP, Journal of Plasma and Fusion Research SERIES, 8, pp.1308-1312 , 2009.06.
67. Y. Yamagata, M. Naka, H. Shinozaki, K. Tomita, K. Uchino, M. Kai, Y. Manabe, Electrode temperature distribution and Ba atom emission in a low-pressure fluorescent lamp, Proceedings of Plasma Science Symposium 2009 and the 26th Plasma Processing Symposium (Nagoya, Japan, February 2-4, 2009), pp. 310-311, 2009.02.
68. Yukihiko Yamagata, Sho Naito, Makoto Kai, Kentaro Tomita, Kiichiro Uchino, Yoshio Manabe, Relationship between distribution of electrode temperature and emission characteristics of emitter material in low-pressure fluorescence lamp, Proceedings of Plasma Science Symposium 2009 and the 26th Plasma Processing Symposium (Nagoya, Japan, February 2-4, 2009), pp.73-74, 2009.02.
69. Y. Yamagata, S. Nishimoto, H. Ooga, S. Hassaballa, K. Tomita, K. Uchino, Measurements of electron temperature and density of pulse filament discharge using laser Thomson scattering technique, Proceedings of Plasma Science Symposium 2009 and the 26th Plasma Processing Symposium (Nagoya, Japan, February 2-4, 2009), pp. 278-279, 2009.02.
70. R. Mibuka, S. Hassaballa, K. Uchino, H. Yurimoto, R. Todokoro, K. Kumondai and M. Ishihara, Characteristics of post-ionization using a femto-second laser, Applied Surface Science, Vol. 255, Issue 4, pp. 1595-1598, 2008.12.
71. Kentaro Tomita, Taisuke Kagawa, Kiichiro Uchino,Sunao Katsuki, Hidenori Akiyama, Diagnostics of EUV Plasmas Using Collective Laser Thomson Scattering, Proceedings of The 3rd International School of Advanced Plasma Technology (Varenna, Italy, 7/28-31, 2008), pp.75-76, 2008.07.
72. Kiichiro Uchino,Shuhei Nishimoto, Akihiko Akune, Yasushi Sonoda, Kentaro Tomita, Safwat Hassaballa, Yukihiko Yamagata, Thomson Scattering Diagnostics of Dielectric-Barrier-Discharge Plasmas, Proceedings of The 3rd International School of Advanced Plasma Technology (Varenna, Italy, 7/28-31, 2008), pp.101-102, 2008.07.
73. T. Ueda, A. Samir, Y. Egashira, G. Yamashita, S. Shimada, Y. Yamagata, K. Uchino, Y. Manabe, Effect of Glow-to-Arc Transition on Loss Mechanism of Ba Atoms from Electrode of Fluorescent Lamp, Jpn. J. Appl. Phys., Vol. 46, No. 10A, pp. 6828-6830, 2007.10.
74. A. Samir, G. Yamashita, Y. Egashira, S. Shimada, Y. Yamagata, K. Uchino, T. Ueda, Y. Manabe, Loss of Ba Atom from the Electrode of Fluorescent Lamp Operating under AC and DC Discharges, 電気学会論文誌A, 第127巻, 第9号, pp. 543 548, 2007.09.
75. Akira Sumitani, Takanobu Ishihara, Teruaki Fukuoka, Kiichiro Uchino, Elucidation of Steplike Output Energy Decrease Observed in ArF Excimer Laser for Microlithography, Jpn. J. Appl. Phys., Vol. 46, No. 5A, pp. 2921-2925 , 2007.05.
76. A. S. AlyHendy, G. Yamashita, Y. Yamagata, K. Uchino, T. Ueda, Y. Manabe, Study on Temporal and Spatial Distributions of Ba Atoms in a Fluorescent Lamp Discharge Using Laser-Induced Florescence, Jpn. J. Appl. Phys., Vol. 45, No. 10B, pp.8109-8112 , 2006.10.
77. M. A. Mansour, Akinobu Nakamura, Y. Yamagata, K. Uchino, Measurements of Electron Energy Distribution Functions of Pulse-Modulated Argon and Argon-Oxygen Inductively Coupled Plasma Using Laser Thomson Scattering, Jpn. J. Appl. Phys., Vol. 45, No. 10B, pp.8118-8122 , 2006.10.
78. A. Sumitani, T. Ishihara, T. Fukuoka, K. Uchino, Investigation of a Step-Like Output Energy Decrease Observed in an ArF Excimer Laser for Microlithography, Jpn. J. Appl. Phys., Vol. 45, No. 38, pp. L1030- L1032, 2006.09.
79. K. Teii, Y. Kouzuma, K. Uchino , In vacuo substrate pretreatments for enhancing nanodiamond formation in electron cyclotron resonance plasma , Journal of Vacuum Science & Technology A, Vol. 24, No. 5 1802-1806 , 2006.09.
80. Noguchi M, Hirao T, Shindo M, Sakurauchi K, Yamagata Y, Uchino K, Kawai Y, Muraoka K, Comparative studies of the laser Thomson scattering and Langmuir probe methods for measurements of negative ion density in a glow discharge plasma, PLASMA SOURCES SCIENCE & TECHNOLOGY, 10.1088/0963-0252/12/3/314, 12, 3, 403-406, Vol. 12, No. 3, pp. 403-406, 2003.08.
81. Y. Kouzuma, K. Teii, K. Uchino, K. Muraoka, Diamond nucleation density as a function of ion-bombardment energy in electron cyclotron resonance plasma, PHYSICAL REVIEW B, 10.1103/PhysRevB.68.064104, 68, 6, Vol. 68, No. 6, art. no. 064104, 2003.08.
82. M. Noguchi, T. Hirao, K. Sakurauchi, Y. Yamagata, H. Naitou, M. Yagi, K. Uchino, K. Muraoka, One-Dimensional Simulation of Photo-Detached Electrons in Negative Ion Plasmas, プラズマ・核融合学会誌, Vol. 79, No. 3, pp. 274-281, 2003.03.
83. J. S. Gao, K. Umeda , K. Uchino , H. Nakashima , K. Muraoka, Plasma Breaking of Thin Films into Nano-Sized Catalysts for Carbon Nanotube Synthesis, Materials Science and Engineering A, 10.1016/S0921-5093(02)00912-7, 352, 1-2, 308-313, Vol. 352, No. 1-2, pp. 308-313, 2003.02.
84. S. Narishige, S. Kitamura, S. Sakemi, K. Tomita, K. Uchino, K. Muraoka, T. Sakoda, Thomson Scattering Diagnostics of Glow Discharge Plasmas Produced in Raman Active Gases, Jpn. J. Appl. Phys., 10.1143/JJAP.41.L1259, 41, 11A, L1259-L1262, Vol.41 Part2, No11A, pp. L1259-L1262, 2002.11.
85. K. Muraoka, K.Uchino, Y. Yamagata, Y. Noguchi, M. Mansour, P. Suanpoot, S. Narishige, M. Noguchi, Laser Thomson scattering studies of glow discharge plasmas, Plasma Sources Sci. Technol., 10.1088/0963-0252/11/3A/321, 11, 3A, A143-A149, Vol. 11, No. 3A, pp. A143-A149, 2002.09.
86. Y. Kouzuma, K.Teii, K. Uchino, K. Muraoka, Diamond Nucleation Enhancement on Si by Controlling Ion-Bombardment Energies in an Electron Cyclotron Resonance Plasma, Japanese Journal of Applied Physics, 10.1143/JJAP.41.5749, 41, 9, 5749-5750, Part1 Vol.41, Part1, No. 9, pp. 5749-5750, 2002.09.
87. M. Noguchi, K. Ariga, T. Hirao, P. Suanpoot, Y. Yamagata, K. Uchino, K. Muraoka, Laser Thomson Scattering Measurements of Negative Ion Density in a Glow Discharge Plasma, Plasma Sources Science and Technology, 10.1088/0963-0252/11/1/307, 11, 1, 57-59, Vol. 11, No. 1, pp. 57-59, 2002.03.
88. P. Suanpoot, S. Narishige, Y. Yamagata, K. Uchino, K. Muraoka, M. Noguchi, Applicabilities of Laser Thomson Scattering to Various Kinds of Discharge Plasmas, プラズマ・核融合学会誌, Vol. 78, No. 3, pp. 242-247, 2002.03.
89. Y. Noguchi, A. Matsuoka, K. Uchino, K. Muraoka, Direct Measurements of Electron Density and Temperature Distributions in a Micro-discharge Plasma for a Plasma Display Panel, Journal of Applied Physics, 10.1063/1.1419264, 91, 2, 613-616, Vol. 91, No. 2, pp. 613-616, 2002.02.
90. H. Tanaka, A. Takahashi, T. Okada, M. Maeda, K. Uchino, T. Nishisaka, A. Sumitani, H. Mizoguchi, Production of Laser-heated Plasma in High-pressure Ar Gas and Emission Characteristics of Vacuum Ultraviolet Radiation from Ar2 Excimers, Applied Physics B, 10.1007/s003400200807, 74, 4-5, 323-326, Vol. 74, pp. 323-326, 2002.01.
91. M. D. Bowden, R. Tabata, P. Suanpoot, K. Uchino, K. Muraoka, M. Noguchi, Measurements of the Electron Energy Distribution Function in an Ar/CF4 Inductively Coupled Plasma, Journal of Applied Physics, 10.1063/1.1398775, 90, 5, 2158-2161, Vol.90, No.5, pp.2158-2161, 2001.05.
92. M. A. M. ElSabbagh, M. D. Bowden, K. Uchino, K. Muraoka, Observations of Bi-Maxwellian and Single Maxwellian Electron Energy Distribution Functions in a Capacitively Coupled Radio-Frequency Plasmas by Laser Thomson Scattering, Applied Physics Letter, 78, 21, 3187-3189, Vol.78, No.21, pp.3187-3189, 2001.01.
93. Y. Noguchi, A. Matsuoka, M. D. Bowden, K. Uchino, K. Muraoka, Measurements of Electron Temperature and Density of a Micro-Discharge Plasma Using Laser Thomson Scattering, Japanese Journal of Applied Physics, 10.1143/JJAP.40.326, 40, 1, 326-329, Vol.40, No.1, pp.326-329, 2001.01.
94. S. Narishige, S. Suzuki, M. D. Bowden, K. Uchino, K. Muraoka, T. Sakoda, T., W. Z. Park, Thomson Scattering Measurement of Electron Density and Temperature of a Microwave Plasma Produced in a Hydrogen Gas at a Moderate Pressure, Japanese Journal of Applied Physics, 10.1143/JJAP.39.6732, 39, 12A, 6732-6736, Vol.39, No.12A, pp. 6732-6736, 2000.12.
95. Y. M. Sung, K. Uchino, K. Muraoka, T. Sakoda, Studies on the Optimum Condition for the Formation of a Neutral Loop Discharge Plasma, Journal of Vacuum Science & Technology A, 10.1116/1.1286391, 18, 5, 2149-2152, Vol.18, No.5, pp.2149-2152, 2000.05.
96. A. Takahashi, T. Okada, T. Hiyama, M. Maeda, K. Uchino, R. Nohdomi, H. Mizoguchi, Ar2 Excimer Emission from a Laser-heated Plasma in a High-pressure Argon Gas, Applied Physics Letter, Vol.77, No.25, pp.4115-4117, 2000.01.
97. N. Kataoka, M. Itagaki, K. Uchino, K. Muraoka, A. Takahashi, T. Okada, M. Maeda, Performance Improvement of a Discharge-Pumped ArF Excimer Laser by Xenon Gas Addition, Japanese Journal of Applied Physics, 10.1143/JJAP.38.6735, 38, 12A, 6735-6738, Vol.38, No.12A, pp. 6735-6738, 1999.12.
98. M.D. Bowden, H. Kudo, K. Uchino, K. Muraoka, M. Noguchi, A Thomson Scattering Measurement System Based on an Infrared Laser, Japanese Journal of Applied Physics, 10.1143/JJAP.38.4924, 38, 8, 4924-4925, Vol.38, No.8A, pp. 4924-4925, 1999.08.
99. M. D. Bowden, Y. Goto, H. Yanaga, P. J. A. Howarth, K. Uchino, K. Muraoka, A Thomson Scattering Diagnostic System for Measurement of Electron Properties of Processing Plasmas, Plasma Sources Science and Technology, 10.1088/0963-0252/8/2/002, 8, 2, 203-209, Vol. 8, pp. 203-209, 1999.08.
100. K. Miyazaki, T. Kajiwara, K. Uchino, K. Muraoka, T. Okada, M. Maeda, Atomic Hydrogen Temperature in Silane Plasmas Used for the Deposition of a-Si:H Films, Journal of Vacuum Science & Technology A, 10.1116/1.582042, 17, 6, 3197-3201, Vol.17, No.6, pp. 3197-3201, 1999.06.
101. M.D. Bowden, Y. Goto, T. Hori, K. Uchino, K. Muraoka, M. Noguchi, Detection Limit of Laser Thomson Scattering for Low Density Discharge Plasmas, Japanese Journal of Applied Physics, 10.1143/JJAP.38.3723, 38, 6A, 3723-3730, Vol.38, No.6A, pp. 3723-3730, 1999.06.
102. M. D. Bowden, M. Kogano, T. Hori, K. Uchino, K. Muraoka, Comparison of Electron Property Measurements in an Inductively Coupled Plasma Made by Langmuir Probe and Laser Thomson Scattering Techniques, Journal of Vacuum Science & Technology A, 10.1116/1.581610, 17, 2, 493-499, Vol. 17, No. 2, pp. 493-499
 , 1999.02.
103. K. Furukawa, Y. C. Liu, H. Nakashima, D. W. Gao, Y. Kashiwazaki, K. Uchino, K. Muraoka, Effects of Oxygen Content on Properties of Silicon Oxide Films Prepared at Room Temperature by Sputtering-type Electron Cyclotron Resonance Plasma, Journal of Applied Physics, 10.1063/1.368683, 84, 8, 4579-4584, Vol. 84, No. 8, pp. 4579-4584, 1998.08.
104. K. Muraoka, K. Uchino, M. D. Bowden, Diagnostics of Low-density Glow Discharge Plasma Using Thomson Scattering, Plasma Physics and Controlled Fusion, 10.1088/0741-3335/40/7/002, 40, 7, 1221-1239, Vol. 40, No. 7, pp. 1221-1239, 1998.07.
105. K. Furukawa, Y. C. Liu, H. Nakashima, D. W. Gao, K. Uchino, K. Muraoka, H. Tsuzuki, Observation of Si Cluster Formation in SiO2 Films through Annealing Process using X-ray Photoelectron Spectroscopy and Infrared Techniques, Applied Physics Letters, 10.1063/1.120865, 72, 6, 725-727, Vol. 72, No. 6, pp. 725-727, 1998.06.
106. T. Hori, M. Kogano, M. D. Bowden, K. Uchino, K. Muraoka, A Study of Electron Energy Distributions in an Inductively Coupled Plasma by Laser Thomson Scattering, Journal of Applied Physics, 10.1063/1.366915, 83, 4, 1909-1916, Vol. 83, No. 4, pp. 1909-1916, 1998.04.
107. Tatsuya Sakoda, Takayuki Miyao, Kiichiro Uchino, Katsunori Muraoka, Studies of a magnetic neutral loop discharge based on laser diagnostics of electron behavior and atomic processes, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 36, 11, 6981-6985, 1997.11, In order to understand plasma formation processes in a neutral loop discharge, measurements of population densities of excited levels of helium atoms were performed using laser induced fluorescence (LIF) spectroscopy. At the same time, profiles of electron density ne and electron temperature Te were measured using Thomson scattering. The results of these measurements were analyzed using a collisional-radiative model of helium atoms in the plasma. It was found that population densities of excited levels of the helium atoms were consistent with the values of ne and Te. This indicates that it is not necessary to consider an existence of a high energy electron component which may be supposed to theoretically exist in addition to the Maxwellian energy distribution function for the bulk of electrons at the measured temperature Te. Also, it was shown that the energy deposition to electrons in the vicinity of the neutral loop plays a essential role in the formation of the neutral loop discharge plasma..
108. W. Cronrath, N. Mayumi, M. D. Bowden, Kiichiro Uchino, K. Muraoka, M. Yoshida, A study of ion velocity distribution functions in processing plasmas produced by electron cyclotron resonance discharges, Journal of Applied Physics, 10.1063/1.365868, 82, 3, 1036-1041, 1997.08, Ion velocity distribution functions were measured using Doppler-shifted laser-induced fluorescence spectroscopy in an electron cyclotron resonance discharge in argon. The influence of the magnetic field configuration on the distributions was studied by making measurements with different magnetic field configurations. Results of a two-dimensional hybrid model of the discharge were used to help interpret the measured data. The results from the experiment and the simulation indicated that the magnetic field configuration had a strong influence on the ion velocity distribution functions. From the simulation it was concluded that the magnetic field configuration determined the axial distributions of plasma potential and electron density, and how these plasma parameters determined the ion velocity distribution function in the downstream region of the discharge..
109. W. Cronrath, M. D. Bowden, Kiichiro Uchino, K. Muraoka, H. Muta, M. Yoshida, Spatial distributions of electron temperature and density in electron cyclotron resonance discharges, Journal of Applied Physics, 10.1063/1.364262, 81, 5, 2105-2113, 1997.03, Spatial profiles of electron density and temperature of electron cyclotron resonance discharge plasmas have been successfully measured using laser Thomson scattering. The results, thus obtained, were valuable for quantitative comparison with results of a computer simulation. Measurements were performed for two cases with different locations of the electron cyclotron resonance zones. Simulation results obtained from a hybrid code, which treats ions and neutral particles as discrete particles and electrons as a fluid, were fitted to the experimental profiles of the electron density and temperature by adjusting the microwave power deposition profiles. From these comparisons and an analysis of other simulation data, it was found that the large difference of radial electron density profiles for two discharge conditions was caused by the difference of radial space-charge electric-field distributions. The radial electron temperature distribution determined the radial electric field that drove the ions radially and also resulted in a peaked electron density profile for one case and a more uniform profile for the other case. It is also shown that Coulomb collisions of electrons with ions as well as electron-neutral collisions are important for the analysis of electron behavior along the magnetic field lines..
110. Katsuhiko Furukawa, Yichun Liu, Dawei Gao, Hiroshi Nakashima, Kiichiro Uchino, Katsunori Muraoka, In situ FT-IR reflective absorption spectroscopy for characterization of SiO2 thin films deposited using sputtering-type electron cyclotron resonance microwave plasma, Applied Surface Science, 10.1016/S0169-4332(97)00294-8, 121-122, 228-232, 1997.01, Plasma conditions for depositing high quality SiO2 thin films using a sputtering-type ECR (electron cyclotron resonance) method have been investigated. Film properties have been studied as a function of an oxygen flow rate, FO2, in the range 2-8 sccm with a constant Ar flow rate of 16 sccm. Dielectric breakdown characteristics have been investigated by ramp I-V measurements, indicating that the film prepared with FO2 = 8 sccm to the thickness of 412 Å have a good dielectric breakdown field of 8-10 MV/cm. The deposited films were characterized in terms of refractive index and IR (infra-red) properties using FT-IRRAS (Fourier transform infrared reflective absorption spectroscopy) and ellipsometry. The refractive index of films deposited with more than FO2 = 3 sccm is close to 1.46 which indicates that the films prepared in this range are approximately stoichiometric. In addition, quantitative analysis of the dominant IR (infra-red) mode shows that the peak frequency and FWHM (full width at half-maximum) of a TO (transverse optical phonon) mode for films prepared with more than FO2 = 6 sccm are comparable with thermally grown SiO2, i.e. v = 1075 cm-1 and FWHM = 70 cm-1. These observations indicate the optimum operating condition of the sputtering-type ECR apparatus, at which it can produce high quality films for MOS (metal-oxide semiconductor) device manufacture without the need for substrate heating..
111. Y. C. Liu, Katsuhiko Furukawa, D. W. Gao, Hiroshi Nakashima, Kiichiro Uchino, K. Muraoka, In-situ infrared reflective absorption spectroscopy characterization of SiN films deposited using sputtering-type ECR microwave plasma, Applied Surface Science, 10.1016/S0169-4332(97)00295-X, 121-122, 233-236, 1997.01, High quality amorphous silicon nitride films have been deposited, without substrate heating, using a sputtering-type electron cyclotron resonance (ECR) microwave plasma. The compositional and structural characterizations have been made by means of a Fourier transform infrared (FT-IR) spectrometer and an ellipsometer. The correlation between the microstructure of a-SixNy films and nitrogen gas fraction relative to argon (N2/Ar) is discussed. In-situ Fourier transform infrared reflection absorption spectroscopy (ISFT-IRRAS) has been used to study the properties of a-SixNy/Si interface. The results from ISFT-IRRAS monitoring indicate that the broadening of a Si-N stretching vibration mode, induced by interface stress, decreases with increased film thickness..
112. M. Sato, S. Ishida, N. Isei, A. Isayama, H. Shirai, T. Oyevaar, M. Teranishi, N. Iwama, Kiichiro Uchino, Measurements and analysis of electron cyclotron emission in JT-60U, Fusion Engineering and Design, 10.1016/S0920-3796(96)00639-4, 34-35, 477-481, 1997.01, In order to obtain the time evolution of the electron temperature in JT-60U plasmas, an electron cyclotron emission measurement system with fast time (of the order of microseconds) and high spatial (of the order of centimetres) resolution has been developed. The operation and data acquisition of the system and preliminary data analysis are made automatically. For precise measurement of the electron temperature profile it is important to correct the shift due to relativistic down-shift frequency in present-day tokamak plasmas..
113. K. Miyazaki, T. Kajiwara, Kiichiro Uchino, K. Muraoka, T. Okada, M. Maeda, Detection of hydrogen atoms in silane plasmas using laser-induced fluorescence by Lyman-alpha two-photon and simultaneous Balmer-alpha excitations, Journal of Vacuum Science and Technology A, 10.1116/1.580457, 15, 1, 149-153, 1997.01, Measurements of atomic hydrogen densities in silane plasmas were accomplished using a two-photon excitation from the ground state (principal quantum number n=1) to the n=2 state at 243 nm, a simultaneous excitation from the n=2 state to the n=3 state at 656 nm, and an observation of fluorescence at 656 nm. First, the influence of the laser-induced dissociation of molecules and radicals in silane plasmas on measurements of hydrogen atoms during the application of this excitation scheme was investigated. Then, we determined the absolute density of hydrogen atoms to be (5±2) × 1017 m-3 in a silane plasma at a flow rate of 5 sccm, a pressure of 11 Pa and a rf power of 2 W..
114. Tatsuya Sakoda, Hironori Iwamiya, Kiichiro Uchino, Katsunori Muraoka, Masahiro Itoh, Taijiro Uchida, Electron temperature and density profiles in a neutral loop discharge plasma, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 36, 1 PART A/B, 1997.01, Thomson scattering measurements of electron temperature and density in a neutral loop discharge (NLD) plasma were performed in order to reveal electron behavior around the neutral loop. The method yielded unambiguous and reliable results, enabling quantitative analyses of particle balance to be made. The results showed that the electron temperature had a peak on the neutral loop and, in contrast, the electron density had a peak at a position radially inward from the neutral loop. We suggest that charged particles are produced by electron impact ionization of argon atoms on the neutral loop and then flow radially inward. The effect of the magnetic field strength on the NLD plasma formation is also discussed..
115. T. Hori, M. D. Bowden, Kiichiro Uchino, K. Muraoka, Measurement of non-Maxwellian electron energy distributions in an inductively coupled plasma, Applied Physics Letters, 10.1063/1.117188, 69, 24, 3683-3685, 1996.12, The electron energy distribution function (EEDF) in an argon planar inductively coupled plasma was measured by the method of laser Thomson scattering. In a low-pressure discharge, a clear departure from a Maxwellian distribution function was observed; an unambiguous measurement of a non-Maxwellian distribution in a low-density glow discharge. The non-Maxwellian EEDF became Maxwellian in a higher pressure discharge. These observations were attributed to the lack of randomizing collisions in the low-pressure discharge and the increase in the number of these collisions at higher pressure..
116. Yi Bing Song, Yuichiro Hirakawa, Kiichiro Uchino, Katsunori Muraoka, Tadanori Sakoda, Koji Yanagishita, Shizuo Nakamura, Measurements of molecular densities in low pressure discharge plasmas using laser Raman scattering, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 35, 10, 5509-5513, 1996.12, The possibility of using Raman scattering as a method of molecular density measurements in low pressure discharge plasmas has been investigated. Firstly, the detection limit of Raman signal was examined in low pressure air. It was shown that the Raman scattering from nitrogen molecules was detectable down to 0.06 Pa (particle density of 1.4 × 1019 m-3) when a photon counting detection system was used. The method was then applied to detect methane and its reaction products in an electron cyclotron resonance plasma operated at a pressure of 50 Pa. Densities of CH4, C2H2, C2H6 and H2 were absolutely determined using the calibrated data of the optical system. Also, it was clearly demonstrated that the gas composition in the discharge was dependent on gas flow rate. These experimental results showed the usefulness of the method for quantitative measurements of molecular densities in processing plasmas..
117. T. Hori, M. D. Bowden, Kiichiro Uchino, K. Muraoka, M. Maeda, Measurements of electron temperature, electron density, and neutral density in a radio-frequency inductively coupled plasma, Journal of Vacuum Science and Technology A, 10.1116/1.579911, 14, 1, 144-151, 1996.05, Electron temperature, electron density, and neutral atom density were measured in a radio-frequency (rf) inductively coupled plasma using Thomson and Rayleigh scattering of laser radiation. Measurements were made in an argon discharge for pressures from 1 to 20 mTorr and input rf powers from 100 to 500 W. Spatial distribution profiles were measured for discharges with different aspect ratios. Electron temperature was found to depend on pressure but only weakly on power. Electron density depended strongly on both pressure and power. The neutral density was found to be significantly depleted in the plasma center and this depletion was attributed to heating of the neutrals by charged particle collisions. These results were compared to a simple model of inductively coupled plasmas..
118. K. Miyazaki, T. Kajiwara, Kiichiro Uchino, K. Muraoka, T. Okada, M. Maeda, Laser-induced dissociation of molecules during measurements of hydrogen atoms in processing plasmas using two-photon laser-induced fluorescence, Journal of Vacuum Science and Technology A, 10.1116/1.579907, 14, 1, 125-131, 1996.01, During measurements of hydrogen atoms in discharge plasmas in silane and methane, using a two-photon excitation from the ground state to the n=3 states at 205 nm, the laser-induced dissociation of molecules was found to be the dominant process of hydrogen production, rather than that due to the discharge. Although the laser intensity was kept below the threshold of atomic hydrogen production from parent gases, some reaction products were at high density which were more easily dissociated by the laser irradiation. Quantitative discussions were made of the laser-induced dissociation, and the estimates of reaction product densities were thus made..
119. N. Isei, M. Sato, S. Ishida, Kiichiro Uchino, A. Nagashima, T. Matoba, T. Oyevaar, Development of 180 GHz heterodyne radiometer for electron cyclotron emission measurements in JT-60U, Review of Scientific Instruments, 10.1063/1.1146364, 66, 1, 413-415, 1995.12, A 12-channel heterodyne radiometer system has been developed to obtain electron temperature with high time and spatial resolution from the electron cyclotron emission (ECE) in JT-60U. Resolutions of a single-sideband-type receiver are (1) Δt∼1 μs and (2) Δf=0.5 GHz. The second harmonic extraordinary mode of ECE is utilized for this system and the frequency band is 176-188 GHz. The noise level of the system is determined by unavoidable photon fluctuations, and the signal-to-noise ratio was measured to be about 50 with a video bandwidth of 100 kHz for a signal temperature above ∼200 eV. Details of the design, the obtained performance, and typical measurements are described..
120. H. Takenaga, T. Nakao, Kiichiro Uchino, K. Muraoka, M. Maeda, H. Iguchi, K. Ida, I. Yamada, S. Okamura, H. Yamada, S. Morita, C. Takahashi, K. Matsuoka, Evaluation of radial particle flux profile based on atomic hydrogen density measurements using laser induced fluorescence and emission at Halpha, Nuclear Fusion, 10.1088/0029-5515/35/1/I09, 35, 1, 107-111, 1995.12, Local atomic hydrogen densities inside plasmas of the Compact Helical System (CHS) were measured using laser induced fluorescence tuned to H α, and the results were compared with those calculated using a neutral particle simulation code, in order to determine the penetration energy of hydrogen atoms from the chamber wall into the plasma. The results of these and supplementary measurements of Hα emission intensities using CCD cameras and photomultipliers at various toroidal positions yielded local atomic hydrogen density distributions throughout the whole plasma. The distribution of the particle source rate was evaluated from the atomic hydrogen distribution, and then the radial particle flux profile was obtained from a particle continuity equation. Estimated errors for the latter were ±30% at an absolute level and several per cent in the profile shape. The radial particle flux thus obtained is valuable for evaluations of particle diffusion coefficient and convection velocity..
121. H. Takenaga, K. Shimizu, N. Asakura, S. Tsuji-Iio, M. Shimada, M. Kikuchi, Kiichiro Uchino, K. Muraoka, Particle confinement study in hot ion H mode discharges of JT-60U, Nuclear Fusion, 10.1088/0029-5515/35/7/I08, 35, 7, 853-860, 1995.12, In order to understand the particle confinement properties of the hot ion H mode plasmas of JT-60U, the particle confinement time was estimated through analyses of the neutral particle behaviour based on measurements of the line emission intensity from the neutral particles combined with neutral particle transport simulations. The relationship between the properties of the particle confinement and the energy confinement was then examined. It was found that: (a) the particle confinement time depended strongly on the averaged electron density, (b) the ratio of the particle confinement time to the energy confinement time was in the range of 1-2 and (c) the particle confinement time was well correlated with the edge ion temperature. Furthermore, in order to clarify the roles of the particle confinement in the edge ion power balance, the charge exchange and convective losses were quantitatively evaluated using the distribution of the neutral particle density and the charged particle outflux, both of which were obtained through an analysis of the neutral particle behaviour. The conductive loss was estimated on the basis of the charge exchange and convective losses and the input power, and then the thermal diffusivity was estimated. From these estimates, it was found that the contributions of the charge exchange and convective losses in the edge power balance were small, and the increase of the edge ion temperature was caused by a decrease of the thermal diffusivity at the plasma edge..
122. Wolfgang Cronrath, Hiroyuki Tanaka, Mark D. Bowden, Kiichiro Uchino, Katsunori Muraoka, Measurement of the neutral particle density in an electron cyclotron resonance plasma by rayleigh scattering, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.34.L1402, 34, 10 B, L1402-L1404, 1995.10, The neutral atom density in an electron cyclotron resonance plasma has been directly measured for the first time using a combination of Rayleigh and Thomson scattering. The measurements were made in the source region of a 3 mTorr argon discharge, and indicated that the neutral atom density was at least 50% less than would be expected at a gas pressure of 3 mTorr. The decrease in the neutral atom density is attributed to the effect of ion-neutral charge exchange collisions in the plasma. The accuracy of the measurement was found to depend on the contribution of metastable atoms to the measured scattered signal..
123. Kiichiro Uchino, T. Kubo, H. Dozono, H. Yamakoshi, K. Muraoka, M. Maeda, Akihiko Takahashi, M. Kato, Thomson-scattering diagnostics of Kr/Ne and Kr/He plasmas using a picosecond laser, Applied Physics B: Lasers and Optics, 10.1007/BF01090938, 61, 2, 165-168, 1995.08, Thomson scattering from plasmas in high-pressure discharges for rare-gas-halide excimer-laser pumping was observed using a frequency-doubled 300 ps Nd: YAG laser. A temporal resolution of 1 ns was realized for the Thomson-scattering measurement, and detailed temporal changes of the electron density and temperature were measured in Kr/Ne and Kr/He plasmas. Calculations using a computer simulation showed good agreement with the experimental results, implying that the plasma dynamics is properly treated in the simulation..
124. H. Takenaga, N. Asakura, K. Shimizu, S. Tsuji, M. Shimada, M. Kikuchi, Kiichiro Uchino, K. Muraoka, Analyses of neutral particle penetration and particle confinement in JT-60U, Journal of Nuclear Materials, 10.1016/0022-3115(94)00643-1, 220-222, 429-432, 1995.01, In order to understand particle confinement properties, the particle balance in JT-60U has been quantitatively analyzed. The charged particle source due to the ionization of hydrogen atoms penetrating into the main plasma was estimated based on measurements of the emission intensity at the Balmer alpha line combined with a simulation using a Monte-Carlo neutral particle transport code. The analyses were performed systematically for the L- and H-mode plasmas of JT-60U, and a data of the global particle confinement time was obtained. It was found that (1) the dependence of the particle confinement time on the averaged electron density and (2) the correlation of the particle confinement time and energy confinement time were different for different operating conditions..
125. Yi Bing Song, Tsukasa Hori, Kiichiro Uchino, Katsunori Muraoka, Tadanori Sakoda, Koji Yanagishita, Sizuo Nakamura, Hiroyuki Yamakawa, Development of a barometer using rayleigh scattering in the medium vacuum region, Journal of the Vacuum Society of Japan, 10.3131/jvsj.38.11, 38, 1, 11-16, 1995.01, The feasibility of employing laser Rayleigh scattering as pressure sensor in the medium vacuum region (1-103 Pa) was investigated by performing two experiments. The first experiment was aimed at demonstrating that such a pressure sensor could be realized. For this purpose, a YLF laser was used. The results were i) the stray light level was reduced to 2.7 Pa, and ii) signal linearity was obtained for the pressure range between 2.7 Pa and 1.2 × 103 Pa with an error of less than 7%. The second experiment was performed to demonstrate that a compact pressure sensor could be fabricated. For this purpose, a laser diode was used, and signals were successfully detected down to 130 Pa with an error of less than 9%. This means that the sensor will be realized if the detection lower limit can be improved by a factor of one hundred..
126. L. Muraoka, K. Miyazaki, U. Czarnetzki, T. Kajiwara, Kiichiro Uchino, H. Takenaga, T. Okada, M. Maeda, T. Yamauchi, T. Shoji, Diagnostics for the spatial distribution of hydrogen atoms around the divertor region, Journal of Nuclear Materials, 10.1016/0022-3115(94)00540-0, 220-222, 563-566, 1995.01, For measurements of spatial distributions of hydrogen atoms around the divertor region, laser-induced fluorescence (LIF) based on various two-phonon excitation schemes from the ground level is discussed, and merits and demerits under different experimental conditions are compared. Excitation to the n=3 level using an ArF excimer laser (wavelength = 193 nm) and its Raman shifts in deuterium gas (205 and 219 nm) and observation at Balmer alpha transition (656 nm) was found to be the best for the above purpose. A design study of the fluorescence observation and estimation of expected signal to noise (SN) ratios were performed for measurements of atomic hydrogen densities on plasmas around the JFT-2M tokamak divertor, showing that such a measurement is possible..
127. H. Iguchi, K. Ida, H. Yamada, K. Itoh, Sanae Itoh, K. Matsuoka, S. Okamura, H. Sanuki, I. Yamada, H. Takenaga, Kiichiro Uchino, K. Muraoka, The effect of magnetic field configuration on particle pinch velocity in compact helical system (CHS), Plasma Physics and Controlled Fusion, 10.1088/0741-3335/36/7/001, 36, 7, 1091-1097, 1994.07, Radial particle transport has been experimentally studied in the low-aspect-ratio heliotron/torsatron device CHS. A non-diffusive outward particle flow (inverse pinch) is observed in the magnetic configuration with the magnetic axis shifted outward, while an inward pinch, like in tokamaks, is observed with the magnetic axis shifted inward. This change in the direction of anomalous particle flow is not due to the reversal of temperature gradient nor the radial electric field. The observation suggests that the particle pinch velocity is sensitive to the magnetic field structure..
128. M. D. Bowden, T. Okamoto, F. Kimura, H. Muta, Kiichiro Uchino, K. Muraoka, T. Sakoda, M. Maeda, Y. Manabe, M. Kitagawa, T. Kimura, Thomson scattering measurements of electron temperature and density in an electron cyclotron resonance plasma, Journal of Applied Physics, 10.1063/1.353046, 73, 6, 2732-2738, 1993.12, Electron temperature Te and density ne in the source region of an electron cyclotron resonance discharge have been measured by incoherent Thomson scattering of the beam from a 0.5 J yttrium aluminum garnet laser. This is the first experiment in which this technique, routinely used on fusion plasmas, has been applied to a processing plasma. Measurements were made in an argon discharge at pressures from 0.3 to 2 mTorr and microwave powers from 250 to 1000 W. Velocity distributions were measured both parallel and perpendicular to the magnetic field and a slight anisotropy of electron temperature was observed for low-pressure discharges. Temperatures in the range of 1-5 eV and densities in the range of 2-10×1017 m -3 were measured. Te and ne were found to strongly depend on pressure but only weakly on the input power and discharge magnetic field. No deviations from a Maxwellian velocity distribution were observed..
129. M. D. Bowden, F. Kimura, H. Muta, Kiichiro Uchino, K. Muraoka, Study of the effect of a probe on the plasma in the source region of an electron cyclotron resonance discharge, Journal of Vacuum Science and Technology A, 10.1116/1.578664, 11, 6, 2893-2896, 1993.01, Langmuir probes are commonly used to measure electron density and temperature in the low temperature and low density plasmas used in plasma processing, although the plasma conditions are sometimes not ideal for such measurements. We report measurements of the perturbing effect of such probes in the high magnetic field region of an electron cyclotron resonance discharge by making Thomson scattering measurements of electron temperature and density under normal operating conditions and also in the presence of a probe. The results revealed that the probe clearly qualitatively changed the plasma. An attempt to quantify this change appeared to indicate that the effect of the probe was to decrease the electron density and increase the electron temperature in the vicinity of the probe..
130. Katsunori Muraoka, Chikahisa Honda, Kiichiro Uchino, Toshinori Kajiwara, Keiji Matsuo, Mark Bowden, Won Zoo Park, Yasuyuki Hirakawa, Kenji Tanaka, Mitsuo Maeda, Tatsuo Okada, Laser diagnostics of edge plasmas and laser diagnostics of plasmas for industrial applications (invited), Review of Scientific Instruments, 10.1063/1.1143547, 63, 10, 4913-4919, 1992.12, In plasma physics, laser diagnostics were first developed to probe the core region of magnetically confined high-temperature plasmas, but the advent of various new lasers has turned out to be useful for edge plasma studies. The recent developments of various arc and glow discharges for industrial plasma applications have required measurement of the same quantities as in the edge plasma studies and expertise in the latter has been fully exploited for the former. The experience thus gained has then been used for the advantage in the studies of edge plasma behavior in high-temperature plasmas. The interplay of these two fields of plasma studies, where laser diagnostics of plasmas (which we call "laser-aided plasma diagnostics") is extensively used, is discussed..
131. Kiichiro Uchino, H. Takenaga, T. Kajiwara, T. Okada, K. Muraoka, M. Maeda, H. Iguchi, K. Ida, S. Okamura, H. Yamada, K. Matsuoka, Understanding atomic hydrogen behaviour in pumped divertor plasmas, Journal of Nuclear Materials, 10.1016/S0022-3115(06)80033-4, 196-198, C, 210-214, 1992.12, In order to set up a data base and diagnostic capability for understanding atomic hydrogen behaviour in pumped divertor plasmas, an experiment and a feasibility study using a novel laser-induced fluorescence (LIF) technique were performed. For the former, combined measurements of LIF tuned to Hα and emission intensities at Hα/Hβ were carried out on the compact helical system (CHS). The comparison of the measured data and a particle simulation code revealed atomic hydrogen behaviour quantitatively, providing a full estimate of toroidally and poloidally asymmetric distributions of hydrogen atoms. In order to supplement the data base around the pumped divertor region, the applicability of an LIF technique which uses two-photon excitation from the ground state was examined, based on the real optical constraints of the envisaged JET pumped divertor. It was concluded that it is feasible and the only remaining problem is not a serious one..
132. Toshinori Kajiwara, Tatsuya Shinkawa, Kiichiro Uchino, Mitsuharu Masuda, Katsunori Muraoka, Tatsuo Okada, Mitsuo Maeda, Sigeru Sudo, Tokuhiro Obiki, Application of two-photon-excited laser-induced fluorescence to atomic hydrogen measurements in the edge region of high-temperature plasmas, Review of Scientific Instruments, 10.1063/1.1142296, 62, 10, 2345-2349, 1991.12, A two-photon-excited laser-induced fluorescence (LIF) was applied to measurement of atomic hydrogen densities in the edge region of high-temperature plasmas of Heliotron E for the first time. In this application, fluorescence signals were observed coaxially to the laser beam. This was possible because, in two-photon-excitation LIF, the visible fluorescence is localized at the laser focus and stray light can be completely eliminated by optical spatial filters, allowing much easier optical access than in previous LIF experiments. The densities at the initiation of the discharge and at the quasisteady state of the discharge were determined to be 3 X 1016 and 1 X 1016 m-3, respectively within an error of a factor of 2. Optimization to maximize the signal-to-noise ratio of the observation and resulting detection limit were discussed and confirmed the above results..
133. Kiichiro Uchino, Y. Kubo, K. Muraoka, T. Sakoda, H. Yamakoshi, M. Kato, Akihiko Takahashi, M. Maeda, Investigation of electron density and velocity distribution in high-pressure discharges for excimer laser pumping using laser Thomson scattering, Journal of Applied Physics, 10.1063/1.350292, 70, 1, 41-45, 1991.12, Thomson scattering from plasmas in high-pressure discharges for rare-gas halide excimer laser pumping was observed using an yttrium-aluminum-garnet laser with a second harmonic generator, combined with a double-monochromator to reject large signal from Rayleigh scattering. The results showed the electron velocity distribution to be Maxwellian which was different from prediction of computer simulations, while variation of electron density and temperature with time and gas composition was consistent with results of computer simulations..
134. H. Yamakoshi, M. Kato, Y. Kubo, H. Enokizono, Kiichiro Uchino, K. Muraoka, Akihiko Takahashi, M. Maeda, Thomson scattering diagnostics of discharge plasmas in an excimer laser, Proceedings of SPIE - The International Society for Optical Engineering, 1397, pt 1, 119-122, 1991.01, The electron-velocity distribution function of the discharge plasma in a rare gas halide excimer laser was diagnosed by the Thomson scattering method. The measured electron-velocity distribution function shows that the predicted value by the calculation is accurate. Those results assure that the calculation method which is based on the kinetic calculation using the circuit equations, the Boltzmann equation and the rate equations is effective in the excimer laser simulation..
135. Tadanori Sakoda, Kiichiro Uchino, Shinji Momii, Katsunori Muraoka, Hiroyuki Yamakawa, Pressure Measurement at Medium Vacuum by Rayleigh Scattering of Laser Light, Journal of the Vacuum Society of Japan, 10.3131/jvsj.34.275, 34, 3, 275-278, 1991.
136. Tadanori Sakoda, Shinji Momii, Kiichiro Uchino, Katsunori Muraoka, Mark Bowden, Mitsuo Maeda, Yoshio Manabe, Masatoshi Kitagawa, Tadashi Kimura, Thomson scattering diagnostics of an ecr processing plasma, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.30.L1425, 30, 8, L1425-L1427, 1991, Information of electron behaviour in processing plasmas was obtained for the first time by the Thomson scattering measurements of electron cyclotron resonance (ECR) plasmas after overcoming various difficulties of the experiment. At relatively high microwave power of 500 W and high argon gas pressure of 2 mTorr, the measurements yielded electron temperature and density to be 9±3 eV and (9±2) x 1017 m-3, respectively. Ways of improving detection limit and/or accuracy are discussed..
137. K. Muraoka, Kiichiro Uchino, M. Maeda, T. Kajiwara, K. Matsuo, T. Okada, C. Honda, Y. Suehiro, N. Yano, K. Takeda, H. Hagiwara, M. Akazaki, S. Sudo, K. Kondo, H. Matsuura, T. Mizuuchi, F. Sano, M. Sato, H. Zushi, T. Obiki, Atomic hydrogen behaviour in Heliotron E, Journal of Nuclear Materials, 10.1016/0022-3115(90)90051-N, 176-177, C, 231-235, 1990.12, In order to understand atomic hydrogen behaviour and particle confinement properties in Heliotron E plasmas, techniques of laser induced fluorescence (LIF) have been extensively used, combined with measurements of absolute Balmer alpha emissions and density fluctuations. The results revealed that for an average electron density n ̄e > 1.5 × 1019 m-3, Hα fluorescence allowed the measurements of atomic hydrogen densities and yielded the recycled Franck-Condon neutrals (~ 3 eV) to penetrate into core plasmas, whereas for n ̄e < 1.0 × 1019 m-3, such measurements were perturbed by dissociative-excitation of H2 molecules into the n = 2 state. Also, the global confinement times showed a clear correlation with electron density fluctuations..
138. Hideo Yamakoshi, Mitsuo Kato, Kiichiro Uchino, Tsunehisa Iwata, Mitsuharu Masuda, Katsunori Muraoka, Mitsuo Maeda, Masanori Akazaki, Thomson scattering diagnostics of a discharge-pumped excimer laser, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.28.L1589, 28, 9 A, L1589-L1591, 1989.09, The electron velocity distribution function is the key parameter for understanding chemical kinetics in plasmas of discharge-pumped excimer lasers. Local and unambiguous determination of the parameter is presently only possible by the Thomson scattering, and this letter describes the first observation of the Thomson scattering signals from ruby laser light from an excimer laser. The results revealed otherwise inaccessible structure of the electron temperature, such as an increase of the temperature when the buffer gas was changed from helium to neon..
139. K. Muraoka, Kiichiro Uchino, T. Kajiwara, K. Matsuo, M. Maeda, M. Akazaki, S. Sudo, K. Kondo, O. Motojima, F. Sano, M. Sato, T. Mutoh, H. Zushi, Y. Takeiri, A. Iiyoshi, K. Uo, Neutral-particle behaviour and particle confinement studies in Heliotron E, Journal of Nuclear Materials, 10.1016/0022-3115(89)90321-8, 162-164, C, 514-519, 1989.04, Measurements of neutral-hydrogen density by laser fluorescence spectroscopy on Heliotron E revealed the anisotropy of its distribution in the poloidal cross section and the dependence of the anisotropy on the average electron density for the first time. This indicates the relative importance of the recycling of charged particles localized at divertor traces and that of charge-exchanged neutrals distributed over a surface. These results are used to calculate the global particle confinement time, which is to be correlated with the measurements of Hα emission intensity and the electron density fluctuations, the initial results of which are also shown..
140. Kiichiro Uchino, Katsunori Muraoka, Masanori Akazaki, Takeharu Koga, Mitsuo Maeda, Shigeru Sudo, Osamu Motojima, Fumimichi Sano, Motoyasu Sato, Takashi Mutoh, Hideki Zushi, Yasuhiko Takeiri, Atsuo Iiyoshi, Koji Uo, Studies of Particle Behaviour in Heliotron E by Means of Balmer-Alpha Laser Fluorescence Spectroscopy, Journal of the Physical Society of Japan, 10.1143/JPSJ.57.909, 57, 3, 909-917, 1988.01, Measurements of atomic hydrogen density profiles in Heliotron E plasmas were performed, where attention was focussed on the anisotropy of the profiles in the poloidal cross section. Obtained penetration profiles of atomic hydrogen agreed well with the Monte Carlo code calculations of the penetration of Franck-Condon neutrals when averaged electron densities are larger than 1019 m–3. For, however, experimental profiles decreased steeper than calculated ones. Degree of the anisotropy of the neutral profiles in the poloidal cross section was also found to change with the value of. Global particle confinement time τp was evaluated from the measured atomic hydrogen profile. The results showed that Tp is around 20 ms for B = 1.9 T. In case of NBI plasma, τp increases as increasing the magnetic field strength, while it decreases as increasing the absorbed power..
141. Chikahisa Honda, Mitsuo Maeda, Kiichiro Uchino, Katsunori Muraoka, Masanori Akazaki, Observation of balmer-alpha line profile of hydrogen atoms in plasmas by rapid-frequency-scan laser spectroscopy, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.27.635, 27, 4R, 635-641, 1988, The possibility of an instantaneous determination of the Balmer alpha (Hα) line profile of hydrogen atoms in large plasma devices by rapid-frequency-scan (RAFS) laser spectroscopy is discussed. A detailed analysis of the SN ratio shows that, although the SN ratio in Hαline profile measurements by RAFS is smaller than those in neutral hydrogen density measurements, a remarkable improvement can be obtained by the choice of the optimum saturation parameter and the long-pulse operation. Based on the experiment of the Hαprofile measurement in a hydrogen DC glow discharge plasma by RAFS, the profile distortion in saturated excitation is evaluated. The SN ratio in the profile measurement by RAFS for Heliotron E plasma is estimated from the data on the neutral density measurement..
142. D. Okano, Kiichiro Uchino, A. Shimizu, K. Muraoka, M. Maeda, M. Akazaki, S. Sudo, O. Motojima, A. Iiyoshi, K. Uo, Neutral hydrogen studies in Heliotron-E using Balmer alpha laser fluorescence spectroscopy, Journal of Nuclear Materials, 10.1016/0022-3115(87)90389-8, 145-147, C, 504-507, 1987.02, The technique of the Balmer alpha laser fluorescence spectroscopy was utilized to study the atomic hydrogen behaviour in plasmas in Heliotron-E. The results revealed that the hydrogen atoms in the plasmas were produced at the periphery of the plasma, penetrated as Franck-Condon neutrals and the plasma densities were supported by the ionization of these atoms..
143. Ryouta Hidaka, Tsutomu Ooki, Kouichi Takeda, Katsuyuki Kondo, Hiroshi Kanda, Kiichiro Uchino, Yoshinobu Matsuda, Masanori Akazaki, Ruby-laser scattering diagnostics of a supersonic plasma flow for low-pressure plasma spraying, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.26.L1724, 26, 10 A, L1724-L1726, 1987, Truly reliable measurements of electron temperature and density in a plasma flow for low-pressure plasma spraying (LPPS) were performed for the first time, using incoherent Thomson scattering of ruby-laser light. The results indicate the characteristic feature of a supersonic nozzle flow, namely, successive appearance of oblique shock-wave heating (-1 eV) and compression (4×1021 m−3), and subsequent cooling (-0.2 eV) and rarefaction (1×1021 m−3)..
144. Yoshinobu Matsuda, Yasutoshi Ueda, Kiichiro Uchino, Katsunori Muraoka, Masanori Akazaki, Yasunori Yamamura, Mitsuo Maeda, Energy dependence of angular distributions of sputtered particles by ion-beam bombardment at normal incidence, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.25.8, 25, 1, 8-11, 1986.01, The angular distributions of sputtered Fe-atoms were measured using the laser fluorescence technique during Ar-ion bombardment for energies of 0.6, 1, 2 and 3 keV at normal incidence. The measured cosine distribution at 0.6 keV progressively deviated to an over-cosine distribution at higher energies, and at 3 keV the angular distribution was an overcosine distribution of about 20%. The experimental results agree qualitatively with calculations by a recent computer simulation code, ACAT. The results are explained by the competition between surface scattering and the effects of primary knock-on atoms, which tend to make the angular distributions over-cosine and under-cosine, respectively..
145. Katsunori Muraoka, Kiichiro Uchino, Yoshio Itsumi, Makoto Hamamoto, Mitsuo Maeda, Masanori Akazaki, Toshikazu Kawamoto, Ryuhei Kumazawa, Shoichi Okamura, Keizō Adati, Takashi Aoki, Hideki Fujita, Kazutoshi Hattori, Shigeru Hidekuma, Yoshimi Okubo, Teruyuki Sato, Harold R. Garner, Dan R. Baker, Harry D. Price, Measurements of atomic hydrogen-density profiles in the rfc-xx-m machine using laser fluorescence spectroscopy at the hαtransition, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.24.L59, 24, 1, 59-61, 1985.01, To assist in the study of the power balance in a linear confinement machine, atomic hydrogen-density profiles in plasmas of the RFC-XX-M device were measured using laser fluorescence spectroscopy tuned to the Balmer alpha line. Measured profiles showed marked decreases of neutral densities in the centre of the plasma, which are explained by charge-exchange and electron ionization pumping by the plasma. It is important to note that the neutrals are well burned out in the central cell, N1/Ne≲ 0. 01. Further, charge-exchange losses are quantitatively evaluated and discussed from the neutral-density profiles and parameters of the plasma..
146. K. Muraoka, M. Maeda, T. Okada, C. Honda, M. Hamamoto, Kiichiro Uchino, T. Kajiwara, Y. Matsuda, Y. Itsumi, M. Akazaki, T. Kawamoto, R. Kumazawa, S. Okamura, H. R. Garner, Developments and applications of laser-fluorescence for studies of particle-behaviours in plasma-surface interactions, Journal of Nuclear Materials, 10.1016/0022-3115(84)90498-7, 128-129, C, 977-981, 1984.01, The paper is concerned with systematic developments of laser-fluorescence systems for studies of particle-behaviours in plasma-surf ace interactions, namely from (i) appropriate laser developments needed for the fluorescence studies, and (ii) benchmark experiments to check the plausibilities of the techniques, to (iii) applications in measurements on high-temperature plasmas..
147. Kiichiro Uchino, Yoshio Itsumi, Katsunori Muraoka, Masanori Akazaki, Ruby-Laser Scattering Diagnostics of DC-Arcs in Atmospheric Air, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.23.662, 23, 5R, 1984.01.
148. Kiichiro Uchino, Katsunori Muraoka, Masanori Akazaki, Studies of an Atmospheric Impulse Arc by Ruby-Laser Scattering, IEEJ Transactions on Fundamentals and Materials, 10.1541/ieejfms1972.103.609, 103, 11, 609-616, 1983.
149. Kiichiro Uchino, Kazuyuki Koga, Yoshito Sonoda, Katsunori Muraoka, Masanori Akazaki, Laser resonance scattering studies of the development of a potential step in a low-density dc discharge in hydrogen, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.21.906, 21, 6R, 906-911, 1982.01, The populations of hydrogen atoms in the excited states (In=2 and 3) across the potential step in a DC discharge at low pressure have been measured bylaser resonance scattering, with the laser tuned to the Balmer alpha transition (Hα, wavelength 656.3 nm). The results were used first to deduce the amplitude of the ion-acoustic turbulence, which was excited by the electron-ion streaming instability at the step. The amplitude was high enough to explain the anomalously high electrical resistivity there. Second, the results were used to discuss the cause of the luminosity jump, due to the behavior of electrons distributed in the potential of the ion-acoustic turbulence..
150. M. Maeda, K. Muraoka, M. Hamamoto, Kiichiro Uchino, M. Akazaki, Plasma-surface interaction studies using laser resonance scattering, Journal of Nuclear Materials, 10.1016/0022-3115(82)90190-8, 111-112, C, 95-101, 1982.01, Results of systematic plasma-surface interaction studies by laser resonance scattering are presented. Conventional laser sources have been used to obtain improvements in metallic atom detection of (i) absolute calibration of the optical system, (ii) velocity-distribution function measurements, and (iii) angular distribution measurement of sputtered atoms by ion-beam bombardment. In addition, wide-range (from vacuum UV to visible) tunable sources have been developed based on a high-power excimer laser. Single-shot velocity-distribution function measurements are also described using a fast-frequency scan dye laser..
151. Kiichiro Uchino, Katsunori Muraoka, Masanori Akazaki, Temperature measurement of an atmospheric impulse arc using ruby laser scattering, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.21.1388, 21, 9R, 1982.01.
152. Kiichiro Uchino, Tetsuhiro Muraoka, Katsunori Muraoka, Masanori Akazaki, Studies of an impulse breakdown process in an atmospheric air using ruby-laser scattering diagnostics, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.21.L696, 21, 11, L696-L698, 1982, Local measurements of impulse breakdown plasmas in an atmospheric air using ruby-laser scattering revealed that pressure as high as 12 atm (electron density蝱1.3ȕ1024m-3and temperature蝱3.4 eV) and an electric field of 2.8ȕ104V/m were reached in the arc channel just after the beginning of the discharge (t=0.4 Ɓsec), and that they rapidly approached respective values at DC discharge in the air. The pressure in the arc channel was found uniform across the channel radius each time, and the initial pressure in, and the expansion velocity of, the arc channel at t=0.4 Ɓsec, were enough to cause the resulting shock-wave expansion at later times..
153. Kiichiro Uchino, Katsunori Muraoka, Masanori Akazaki, Laser scattering diagnostics of an atmospheric impulse arc, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.20.1165, 20, 6, 1165-1166, 1981.01.