Prof. Haruo Obara Profile

Prof. Haruo Obara

at Tohoku Univ

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Author

Publications (19)

Proceedings Article | 29 January 2007 Paper

X-ray spectra from weakly ionized linear molybdenum plasma

Haruo Obara, Eiichi Sato, Rudolf Germer, Etsuro Tanaka, Hidezo Mori, Toshiaki Kawai, Takashi Inoue, Akira Ogawa, Kazuyoshi Takayama

Proceedings Volume 6279, 627940 (2007) https://doi.org/10.1117/12.725347

KEYWORDS: X-rays, Plasma, Molybdenum, Electrodes, X-ray sources, Plasma generation, Medical research, Radiography, Power supplies, Chromium

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Proceedings Article | 11 January 2007 Paper

Novel monochromatic x-ray generators and their applications to high-speed radiography

Eiichi Sato, Rudolf Germer, Haruo Obara, Etsuro Tanaka, Hidezo Mori, Toshiaki Kawai, Takashi Inoue, Akira Ogawa, Mitsuru Izumisawa, Toshio Ichimaru, Kiyomi Takahashi, Shigehiro Sato, Kazuyoshi Takayama

Proceedings Volume 6279, 627906 (2007) https://doi.org/10.1117/12.725056

KEYWORDS: X-rays, Radiography, Plasma, Angiography, Iodine, Tungsten, Electrodes, Plasma generation, Cerium, Copper

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Proceedings Article | 11 January 2007 Paper

Enhanced k-edge angiography utilizing a super-fluorescent x-ray generator with a gadolinium-target tube

Eiichi Sato, Rudolf Germer, Haruo Obara, Etsuro Tanaka, Hidezo Mori, Toshiaki Kawai, Takashi Inoue, Akira Ogawa, Shigehiro Sato, Kazuyoshi Takayama

Proceedings Volume 6279, 627911 (2007) https://doi.org/10.1117/12.725174

KEYWORDS: X-rays, Angiography, Gadolinium, Iodine, X-ray sources, Plasma, X-ray imaging, Radiography, Medical research, Pulse generators

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Proceedings Article | 21 September 2005 Paper

Preliminary study for producing higher harmonic hard x-rays from weakly ionized copper plasma

Eiichi Sato, Yasuomi Hayasi, Rudolf Germer, Haruo Obara, Etsuro Tanaka, Hidezo Mori, Toshiaki Kawai, Takashi Inoue, Akira Ogawa, Shigehiro Sato, Kazuyoshi Takayama, Hideaki Ido

Proceedings Volume 5920, 59200U (2005) https://doi.org/10.1117/12.620216

KEYWORDS: X-rays, Plasma, Copper, Electrodes, Hard x-rays, X-ray sources, Plasma generation, Nickel, Medical research, Radiography

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Proceedings Article | 21 September 2005 Paper

Superposition of x-ray spectra using a brass-target plasma triode

Haruo Obara, Eiichi Sato, Yasuomi Hayasi, Etsuro Tanaka, Hidezo Mori, Toshiaki Kawai, Takashi Inoue, Akira Ogawa, Kazuyoshi Takayama, Hideaki Ido

Proceedings Volume 5920, 59200W (2005) https://doi.org/10.1117/12.620207

KEYWORDS: X-rays, Plasma, Copper, Zinc, Radiography, X-ray sources, Electrodes, Superposition, Metals, Medical research

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Proceedings Article | 17 March 2005 Paper

Demonstration of flash K-edge angiography utilizing gadolinium-based contrast medium

Eiichi Sato, Michiaki Sagae, Haruo Obara, Rudolf Germer, Etsuro Tanaka, Hidezo Mori, Toshiaki Kawai, Toshio Ichimaru, Shigehiro Sato, Hidenori Ojima, Kazuhiro Takayama, Hideaki Ido

Proceedings Volume 5580, (2005) https://doi.org/10.1117/12.581179

KEYWORDS: X-rays, Angiography, Tungsten, Photons, Gadolinium, Iodine, X-ray sources, Oxides, Medical research, Power supplies

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Proceedings Article | 17 March 2005 Paper

Superposition of x-ray spectra using double-target plasma triode

Haruo Obara, Eiichi Sato, Etsuro Tanaka, Hidezo Mori, Toshiaki Kawai, Shigehiro Sato, Hidenori Ojima, Kazuyoshi Takayama, Hideaki Ido

Proceedings Volume 5580, (2005) https://doi.org/10.1117/12.581235

KEYWORDS: X-rays, Plasma, Molybdenum, Copper, Radiography, X-ray sources, Electrodes, Superposition, Medical research, Angiography

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Proceedings Article | 17 March 2005 Paper

Intense quasi-monochromatic flash x-ray generator utilizing molybdenum-target diode

Michiaki Sagae, Eiichi Sato, Haruo Obara, Etsuro Tanaka, Hidezo Mori, Toshiaki Kawai, Shigehiro Sato, Hidenori Ojima, Kazuyoshi Takayama, Hideaki Ido

Proceedings Volume 5580, (2005) https://doi.org/10.1117/12.581246

KEYWORDS: X-rays, X-ray sources, Molybdenum, Radiography, Diodes, Angiography, Medical research, Plasma, Pulse generators, Power supplies

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Proceedings Article | 1 August 2003 Paper

Applications of stroboscopic x-ray generators to high-speed radiographies including biomedical applications

Haruo Obara, Masayuki Zuguchi, Eiichi Sato, Etsuro Tanaka, Hidezo Mori, Tatsumi Usuki, Koetsu Sato, Hidenori Ojima, Kazuyoshi Takayama

Proceedings Volume 4948, (2003) https://doi.org/10.1117/12.516875

KEYWORDS: X-rays, Radiography, X-ray imaging, Biomedical optics, X-ray sources, X-ray technology, Transformers, Polymethylmethacrylate, Chromium, Photomultipliers

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Proceedings Article | 1 August 2003 Paper

Quasimonochromatic parallel flash radiography achieved with a plane-focus x-ray tube

Eiichi Sato, Rudolf Germer, Yasuomi Hayasi, Etsuro Tanaka, Hidezo Mori, Toshiaki Kawai, Tatsumi Usuki, Koetsu Sato, Haruo Obara, Masayuki Zuguchi, Toshio Ichimaru, Hidenori Ojima, Kazuyoshi Takayama, Hideaki Ido

Proceedings Volume 4948, (2003) https://doi.org/10.1117/12.516927

KEYWORDS: X-rays, Radiography, Plasma, X-ray sources, Copper, Electrodes, Chromium, X-ray diffraction, Power supplies, Lead

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Proceedings Article | 1 August 2003 Paper

Plasma flash x-ray generator (PFXG-02)

Proceedings Volume 4948, (2003) https://doi.org/10.1117/12.516901

KEYWORDS: X-rays, Plasma, Plasma generation, Iron, Electrodes, Radiography, X-ray sources, X-ray diffraction, Power supplies, Lead

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Proceedings Article | 3 May 2002 Paper

Fundamental study on parallel-beam radiography using a polycapillary plate

Eiichi Sato, Hiroyuki Toriyabe, Yasuomi Hayasi, Etsuro Tanaka, Hidezo Mori, Toshiaki Kawai, Tatsumi Usuki, Koetsu Sato, Haruo Obara, Toshio Ichimaru, Kazuyoshi Takayama, Hideaki Ido, Yoshiharu Tamakawa

Proceedings Volume 4682, (2002) https://doi.org/10.1117/12.465571

KEYWORDS: X-rays, Radiography, Image resolution, Tungsten, X-ray imaging, Photonics, Physics, Medical research, X-ray technology, X-ray optics

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Proceedings Article | 3 May 2002 Paper

Quasi-monochromatic radiography using a high-intensity quasi-x-ray laser generator

Eiichi Sato, Yasuomi Hayasi, Etsuro Tanaka, Hidezo Mori, Toshiaki Kawai, Tatsumi Usuki, Koetsu Sato, Haruo Obara, Toshio Ichimaru, Kazuyoshi Takayama, Hideaki Ido, Yoshiharu Tamakawa

Proceedings Volume 4682, (2002) https://doi.org/10.1117/12.465598

KEYWORDS: X-rays, Plasma, Radiography, Molybdenum, X-ray sources, Electrodes, Plasma generation, Power supplies, Optical filters, Pulse generators

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Proceedings Article | 19 December 2001 Paper

Polycapillary radiography using a quasi-x-ray-laser generator

Eiichi Sato, Yasuomi Hayasi, Etsuro Tanaka, Hidezo Mori, Toshiaki Kawai, Haruo Obara, Toshio Ichimaru, Kazuyoshi Takayama, Hideaki Ido, Tatsumi Usuki, Koetsu Sato, Yoshiharu Tamakawa

Proceedings Volume 4508, (2001) https://doi.org/10.1117/12.450786

KEYWORDS: X-rays, Plasma, Radiography, Copper, X-ray sources, Electrodes, Image resolution, Power supplies, Optical filters, Pulse generators

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Proceedings Article | 17 April 2001 Paper

Observation of cavitation bubble cloud using a stroboscopic x-ray generator

Eiichi Sato, Hidenori Ojima, Kazuyoshi Takayama, Masatoshi Matsumasa, Haruo Obara, Masayuki Zuguchi, Tatsumi Usuki, Koetsu Sato, Kimio Sakamaki, Yoshiharu Tamakawa

Proceedings Volume 4183, (2001) https://doi.org/10.1117/12.424303

KEYWORDS: X-rays, Radiography, Clouds, Cavitation, Iron, Computing systems, X-ray sources, X-ray imaging, Electrodes, Photomultipliers

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The radiographic characteristics of the condenser-discharge stroboscopic x-ray generator and its application to high-speed radiography are described. This generator employs a condenser- discharge medical x-ray generator in conjunction with a new grid-control unit and consists of the following major components: a high-voltage control unit, a condenser unit having a Cockcroft circuit, a grid-control unit, a high- voltage grid-control unit, and a rotating-anode x-ray tube unit. The main condenser of about 500 nF in the unit is charged up to 120 kV by the circuit, and the electric charges in the condenser are discharged to the triode by the grid control unit in conjunction with a high-voltage grid-control unit. The high-voltage grid-control unit is employed in order to insulate the negative high-voltage grid and cathode electrodes from the high-speed grid control unit with almost the ground potential. In this generator the anode and cathode electrodes are applied to high-voltages with maximum values of +60 kV and -60 kV, respectively. Although the tube voltage decreased during the discharging for generating x- rays, the maximum value was equivalent to the initial charging voltage of the main condenser. The maximum values of the tube current and the repetition rate were about 0.5 A and 32 kHz, respectively. The pulse width of the x-rays ranged from 0.01 to 1.0 ms, and the maximum shot number had a value of 32. At a constant filament (cathode) temperature, the x-ray intensity increased according to increases in the charging voltage and to increases in the duration, and the maximum intensity with a duration of 1.0 ms and a charging voltage of 100 kV was 0.66 (mu) C/kg at 1.0 m from the x-ray source. The dimensions of the focal spot had values of about 1 X 1 mm, and both the inner and outer triggering for producing pulse x-rays can be employed. The high-speed radiography was primarily performed by the multiple-shot radiography using a new computed radiography (CR) system in conjunction with the computer- display system with an operation system of Windows NT Workstation 4.0.

Proceedings Article | 17 April 2001 Paper

Application of harder stroboscopic x-ray generator to high-speed radiography

Haruo Obara, Masayuki Zuguchi, Eiichi Sato, Tatsumi Usuki, Koetsu Sato, Hidenori Ojima, Kazuyoshi Takayama, Yoshiharu Tamakawa

Proceedings Volume 4183, (2001) https://doi.org/10.1117/12.424299

KEYWORDS: X-rays, Radiography, Transformers, X-ray technology, X-ray imaging, Aluminum, Pulse generators, X-ray sources, Chromium, Optical filters

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Proceedings Article | 17 April 2001 Paper

Condenser-discharge stroboscopic x-ray generator for medical radiography

Eiichi Sato, Toshio Ichimaru, Haruo Obara, Masayuki Zuguchi, Hidezo Mori, Etsuro Tanaka, Tatsumi Usuki, Koetsu Sato, Hidenori Ojima, Kazuyoshi Takayama, Kimio Sakamaki, Yoshiharu Tamakawa

Proceedings Volume 4183, (2001) https://doi.org/10.1117/12.424302

KEYWORDS: X-rays, Radiography, Electrodes, Chromium, Computing systems, Photomultipliers, Radiology, Control systems, X-ray sources, Windows NT

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The radiogprahic characteritics of the condenser-discahrge stroboscopic x-ray genrator and its application to high-speed radiogprahy are described.This gnerator employs a coneser- discharge medical x-ray gnerator in conjunctionwith a new grid-control unit and consists of the following major componets: a high -voltage control unit, a condenser unit having a Cockcroft circuit,a grid-control unit, a high- voltage grid-control unit,a nd a rotating-anode x-ray tube unit.The main condesner of about 500 nF in the unit is charged up to 120 kV by the circuit and the electric charges inthe condene are dischargd to the triode by the grid control unit i9n conjunction with a hgih-voltage grid-control unti The highv-otalgd grid-control unit is employed inorder to insulate the negative hgih-voltage grid and acathode electrods from th ehgihs-peed grid control unit with almost the ground potnetial. Inthis gnerator, th anode and cathode lectrodes ar applied tohigh-voltages with maximumvalues of +60 kV and -60 kV, respectively. Although the tube voltrage decased during the discharging for gnerating x-rays, the maximum vlaue was equivlaent to th eitnital charging vortlag eof th emiain condenser. Th3 amsximu values of the tub ecurrent and the repetiton rat3 awer about 0.5 A and 32 kHz, respectively. The pulse widthof the x-rays ranged from 0.01 to 1.0 ms, and the maximumshot number ahd a vlaue of 32. At a constant filament (cathode) tmerpature,the x-ray intensity incrased accordign to incrases in teh charging voltage and toincrases in the duration and the maximum intensity with a duration of 1.0 ms and a charging voltage of 100 kV awas 0.66 (mu) C/kf at 1.0 m from the -ray source.The dimensiosn sof the focal spot had values of about 1 X 1 mm, and both the inner and outer triggering for produicng pulse c-rays acan be employed. The hgih-speed radiogrpahy was primari9ly performed by temultpe- shot radiogprhay using a new computed radiogprhay (CR) system in conjuctiown tiht ehcomuter-dispaly sysem with an operationsyste of Windows NT Workstation 4.0.

Proceedings Article | 12 December 1997 Paper

Ignitron-driven soft flash x-ray generator

Michiaki Sagae, Eiichi Sato, Toshio Ichimaru, Haruo Obara, Kimio Sakamaki, Kazuyoshi Takayama, Yoshiharu Tamakawa

Proceedings Volume 3173, (1997) https://doi.org/10.1117/12.294510

KEYWORDS: X-rays, Electrodes, Power supplies, Diffusion, Molybdenum, Carbon, Switches

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Proceedings Article | 1 January 1993 Paper

Conventional metal plasma x-ray-flash techniques using vacuum discharges

Eiichi Sato, Michiaki Sagae, Shingo Kimura, Teiji Oizumi, Yasuomi Hayasi, Yoshiharu Tamakawa, Yutaka Ohta, Shogo Suzuki, Haruo Obara, Hiroshi Seino, Toru Yanagisawa

Proceedings Volume 1801, (1993) https://doi.org/10.1117/12.145732

KEYWORDS: X-rays, Plasma, Copper, Tungsten, Aluminum, High speed photography, Radiography, Photonics, Electrodes, Satellites

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Showing 5 of 19 publications

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