Patents by Inventor Yui Yokota
Yui Yokota has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20210277504Abstract: A metal member according to this invention is composed of polycrystals of a metal made of ruthenium or an alloy containing ruthenium at a maximum ratio. The aspect ratio of a crystal grain of the polycrystalline metal member is 1.5 or more. A plurality of crystal grains forming the metal member are arranged with their major axes being pointed in the same direction, and the number of crystal grains in a section in the major axis direction of the crystal grains is 120 or less per 1 mm2.Type: ApplicationFiled: June 27, 2018Publication date: September 9, 2021Inventors: Akira YOSHIKAWA, Rikito MURAKAMI, Yui YOKOTA, Takayuki NIHEI, Kei KAMADA, Yasuhiro SHOJI, Shunsuke KUROSAWA, Akihiro YAMAJI, Yuji OHASHI
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Patent number: 9920243Abstract: The present invention aims at providing a scintillator for high temperature environments which has satisfactory light emission characteristics under high temperature environments; and a method for measuring radiation under high temperature environments. The scintillator for high temperature environments comprises a colquiriite-type crystal represented by the chemical formula LiM1M2X6 (where M1 is at least one alkaline earth metal element selected from Mg, Ca, Sr and Ba, M2 is at least one metal element selected from Al, Ga and Sc, and X is at least one halogen element selected from F, Cl, Br and I), for example, typified by LiCaAlF6, and the crystal optionally containing a lanthanoid element such as Ce or Eu. The method for measuring radiation under high temperature environments uses the scintillator.Type: GrantFiled: April 2, 2012Date of Patent: March 20, 2018Assignees: TOKUYAMA CORPORATION, TOHOKU UNIVERSITYInventors: Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota
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Patent number: 9388337Abstract: A light emitting element according to one embodiment of the present invention is configured of a metal fluoride crystal which is represented by chemical formula LiM1M2F6 (wherein Li includes 6Li; M1 represents at least one alkaline earth metal element selected from among Mg, Ca, Sr and Ba; and M2 represents at least one metal element selected from among Al, Ga and Sc), said metal fluoride crystal containing 0.02% by mole or more of Eu and having an Eu2+ concentration of less than 0.01% by mole.Type: GrantFiled: April 18, 2013Date of Patent: July 12, 2016Assignees: TOKUYAMA CORPORATION, TOHOKU UNIVERSITYInventors: Sumito Ishizu, Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
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Patent number: 9068114Abstract: [Problems to be Solved] A neutron scintillator excellent in detection efficiency for neutrons, an S/N ratio, and n/? discrimination ability, and a eutectic preferred for the neutron scintillator are provided. [Means to Solve the Problems] A metal fluoride eutectic, in which a lithium fluoride crystal phase and a crystal phase represented by the chemical formula Ca1-xSrxF2 (where x denotes a number greater than 0, but not larger than 1), such as SrF2 or Ca0.5Sr0.5F2, are present in a phase-separated state; a neutron scintillator comprising the eutectic; and a neutron imaging device comprising a combination of the neutron scintillator and a position-sensitive photomultiplier tube.Type: GrantFiled: November 1, 2011Date of Patent: June 30, 2015Assignees: TOKUYAMA CORPORATION, TOHOKU UNIVERSITYInventors: Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
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Publication number: 20150115168Abstract: A light emitting element according to one embodiment of the present invention is configured of a metal fluoride crystal which is represented by chemical formula LiM1M2F6 (wherein Li includes 6Li; M1 represents at least one alkaline earth metal element selected from among Mg, Ca, Sr and Ba; and M2 represents at least one metal element selected from among Al, Ga and Sc), said metal fluoride crystal containing 0.02% by mole or more of Eu and having an Eu2+ concentration of less than 0.01% by mole.Type: ApplicationFiled: April 18, 2013Publication date: April 30, 2015Inventors: Sumito Ishizu, Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
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Patent number: 8933408Abstract: [Problems to be Solved] A colquiriite-type crystal preferred for a scintillator for neutron detection, which has high sensitivity to neutron and which is reduced in background noise attributed to ? rays; a scintillator for neutron detection which comprises this crystal; and a neutron detector are provided. [Means to Solve the Problems] A colquiriite-type crystal represented by the chemical formula LiM1M2X6, such as LiCaAlF6, containing Na and Ce, for example, the colquiriite-type crystal containing at least one alkali metal element selected from the group consisting of Na, K, Rb and Cs, and a lanthanoid element selected from the group consisting of Ce, Pr and Nd, and having an isotopic ratio of 6Li of 20 mol % or more, preferably 50 mol % or more; a scintillator for neutron detection comprising the colquiriite-type crystal; and a neutron detector.Type: GrantFiled: November 1, 2011Date of Patent: January 13, 2015Assignees: Tokuyama Corporation, Tohoku UniversityInventors: Sumito Ishizu, Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
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Patent number: 8809797Abstract: Provided is a scintillator for neutrons that allows the detection of neutrons with superb sensitivity and that is little affected by background noise derived from ?-rays, and a neutron detector that uses the neutron scintillator. The scintillator for neutrons comprises borate that contains at least Mg and a divalent transition element.Type: GrantFiled: December 15, 2011Date of Patent: August 19, 2014Assignees: Tokuyama Corporation, Tohoku UniversityInventors: Hisanori Yamane, Tetsuya Kawano, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto, Kentaro Fukuda, Noriaki Kawaguchi
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Patent number: 8795822Abstract: [Problems to be Solved] A neutron scintillator excellent in neutron detection efficiency and n/? discrimination ability, and a metal fluoride eutectic preferred for the neutron scintillator are provided. [Means to Solve the Problems] A metal fluoride eutectic having a cerium-containing calcium fluoride crystal phase and a lithium fluoride crystal phase present in a phase-separated state, and a neutron scintillator comprising the metal fluoride eutectic.Type: GrantFiled: November 1, 2011Date of Patent: August 5, 2014Assignees: Tokuyama Corporation, Tohoku UniversityInventors: Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
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Patent number: 8642972Abstract: [Problems to be Solved] A neutron scintillator excellent in neutron detection efficiency and n/? discrimination ability, and a neutron detector using the neutron scintillator are provided. [Means to Solve the Problems] A neutron scintillator comprising a eutectic body composed of laminar lithium fluoride crystals and laminar calcium fluoride crystals alternately arranged in layers, the thickness of the lithium fluoride crystal layers in the eutectic body being 0.1 to 5 ?m; or a neutron scintillator comprising a eutectic body composed of laminar lithium fluoride crystals and laminar calcium fluoride crystals alternately arranged in layers, the calcium fluoride crystal layers in the eutectic body being linearly continuous in at least one direction; and a neutron detector basically constructed from any of the neutron scintillators and a photodetector.Type: GrantFiled: April 26, 2011Date of Patent: February 4, 2014Assignees: Tokuyama Corporation, Tohoku UniversityInventors: Kentaro Fukuda, Sumito Ishizu, Noriaki Kawaguchi, Toshihisa Suyama, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota
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Publication number: 20140021355Abstract: The present invention aims at providing a scintillator for high temperature environments which has satisfactory light emission characteristics under high temperature environments; and a method for measuring radiation under high temperature environments. The scintillator for high temperature environments comprises a colquiriite-type crystal represented by the chemical formula LiM1M2X6 (where M1 is at least one alkaline earth metal element selected from Mg, Ca, Sr and Ba, M2 is at least one metal element selected from Al, Ga and Sc, and X is at least one halogen element selected from F, Cl, Br and I), for example, typified by LiCaAlF6, and the crystal optionally containing a lanthanoid element such as Ce or Eu. The method for measuring radiation under high temperature environments uses the scintillator.Type: ApplicationFiled: April 2, 2012Publication date: January 23, 2014Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATIONInventors: Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota
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Publication number: 20130327946Abstract: A novel scintillator for neutron detection is capable of increasing the probability of inducing a nuclear reaction using epithermal neutrons having higher energy than thermal neutrons as a result of increasing thickness in the direction of incidence of neutron radiation. A scintillator for neutron detection includes a colquiriite-type fluoride single crystal containing europium, containing 0.0025 mol % or more and less than 0.05 mol % europium, containing 0.80 atom/nm3 or more 6Li, and being shaped such that the thickness in the thickest part exceeds 1 mm.Type: ApplicationFiled: February 24, 2012Publication date: December 12, 2013Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATIONInventors: Noriaki Kawaguchi, Kentaro Fukuda, Toshihisa Suyama, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
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Publication number: 20130320217Abstract: The present invention is a neutron detection device comprising a neutron detection scintillator composed of a colquiriite-type fluoride single crystal, and a silicon photodiode, characterized in that the single crystal contains only Eu as a lanthanoid and contains 0.80 atom/nm3 or more of 6Li, the content of Eu is 0.0025 to 0.05 mol %, and the thickness of the scintillator exceeds 1 mm. The present invention provides a neutron detection device which has a sufficiently high neutron detection efficiency, is equipped with a neutron detection unit minimally affected by gamma rays, and is compact as a whole and lightweight.Type: ApplicationFiled: March 8, 2012Publication date: December 5, 2013Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATIONInventors: Noriaki Kawaguchi, Kentaro Fukuda, Toshihisa Suyama, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
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Publication number: 20130264482Abstract: Provided is a scintillator for neutrons that allows the detection of neutrons with superb sensitivity and that is little affected by background noise derived from ?-rays, and a neutron detector that uses the neutron scintillator. The scintillator for neutrons comprises borate that contains at least Mg and a divalent transition element.Type: ApplicationFiled: December 15, 2011Publication date: October 10, 2013Inventors: Hisanori Yamane, Tetsuya Kawano, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto, Kentaro Fukuda, Noriaki Kawaguchi
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Publication number: 20130214203Abstract: [Problems to be Solved] To provide a neutron scintillator which shows a large amount of luminescence in response to neutrons and which is excellent in neutron detection efficiency and n/? discrimination ability; and a metal fluoride crystal suitable for the neutron scintillator. [Means to Solve the Problems] A metal fluoride crystal, as a parent crystal, represented by the chemical formula LiM1M2F6 (where M1 represents at least one alkaline earth metal element selected from the group consisting of Mg, Ca, Sr and Ba, and M2 represents at least one metal element selected from the group consisting of Al, Ga and Sc), such as lithium calcium aluminum fluoride, lithium strontium aluminum fluoride, or lithium magnesium aluminum fluoride, the metal fluoride crystal containing at least one alkali metal element selected from the group consisting of Na, K, Rb and Cs, and also containing Eu; and a light-emitting device comprising the crystal, such as a neutron scintillator.Type: ApplicationFiled: November 1, 2011Publication date: August 22, 2013Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATIONInventors: Sumito Ishizu, Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
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Publication number: 20130181137Abstract: A neutron radiation detector has a function that discriminates between neutron radiation and ? radiation based on a difference in pulse shape between photodetection signals from a neutron radiation detection scintillator, which includes a Ce-containing LiCaAlF6 single crystal.Type: ApplicationFiled: May 18, 2011Publication date: July 18, 2013Inventors: Kenichi Watanabe, Atsushi Yamazaki, Akira Uritani, Yoshiyuki Kondo, Tetsuo Iguchi, Noriaki Kawaguchi, Kentaro Fukuda, Toshihisa Suyama, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota
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Publication number: 20130183509Abstract: [Problems to be Solved] A neutron scintillator excellent in neutron detection efficiency and n/? discrimination ability, and a metal fluoride eutectic preferred for the neutron scintillator are provided. [Means to Solve the Problems] A metal fluoride eutectic having a cerium-containing calcium fluoride crystal phase and a lithium fluoride crystal phase present in a phase-separated state, and a neutron scintillator comprising the metal fluoride eutectic.Type: ApplicationFiled: November 1, 2011Publication date: July 18, 2013Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATIONInventors: Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
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Publication number: 20130168561Abstract: [Problems to be Solved] A neutron scintillator excellent in detection efficiency for neutrons, an S/N ratio, and n/? discrimination ability, and a eutectic preferred for the neutron scintillator are provided. [Means to Solve the Problems] A metal fluoride eutectic, in which a lithium fluoride crystal phase and a crystal phase represented by the chemical formula Ca1-xSrxF2 (where x denotes a number greater than 0, but not larger than 1), such as SrF2 or Ca0.5Sr0.5F2, are present in a phase-separated state; a neutron scintillator comprising the eutectic; and a neutron imaging device comprising a combination of the neutron scintillator and a position-sensitive photomultiplier tube.Type: ApplicationFiled: November 1, 2011Publication date: July 4, 2013Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATIONInventors: Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
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Publication number: 20130161519Abstract: [Problems to be Solved] A colquiriite-type crystal preferred for a scintillator for neutron detection, which has high sensitivity to neutron and which is reduced in background noise attributed to ? rays; a scintillator for neutron detection which comprises this crystal; and a neutron detector are provided. [Means to Solve the Problems] A colquiriite-type crystal represented by the chemical formula LiM1M2X6, such as LiCaAlF6, containing Na and Ce, for example, the colquiriite-type crystal containing at least one alkali metal element selected from the group consisting of Na, K, Rb and Cs, and a lanthanoid element selected from the group consisting of Ce, Pr and Nd, and having an isotopic ratio of 6Li of 20 mol % or more, preferably 50 mol % or more; a scintillator for neutron detection comprising the colquiriite-type crystal; and a neutron detector.Type: ApplicationFiled: November 1, 2011Publication date: June 27, 2013Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATIONInventors: Sumito Ishizu, Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
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Publication number: 20130112885Abstract: [Problems to be Solved] A phoswich radiation detector, which can easily discriminate between detection signals on gamma rays and thermal neutrons, and which can selectively acquire signals on thermal neutrons, is provided. [Means to Solve the Problems] In a phoswich radiation detector having two scintillators and discriminating between thermal neutrons and gamma rays, the detector comprises a scintillator for detecting thermal neutrons, such as LiCaAlF6:Eu, which has a light yield of more than 1500 photons/neutron, and a scintillator for detecting gamma rays, which has a permeable end on a shorter wavelength than the light emission wavelength of the thermal neutron scintillator.Type: ApplicationFiled: July 20, 2011Publication date: May 9, 2013Applicants: HIROSHIMA UNIVERSITY, TOHOKU UNIVERSITY, TOKUYAMA CORPORATIONInventors: Hiromitsu Takahashi, Mitsuo Yonetani, Masayuki Matsuoka, Yasushi Fukazawa, Noriaki Kawaguchi, Kentaro Fukuda, Toshihisa Suyama, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
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Publication number: 20130105707Abstract: [Problems to be Solved] A radiation detector, which is improved in the detection efficiency of a photodetector for light emitted by a scintillator, which has excellent long-term operational stability, and which is excellent in time resolution and count rate characteristics, is provided with the use of the scintillator with a short fluorescence lifetime. [Means to Solve the Problems] A radiation detector is constructed by installing an optical wavelength conversion layer, which is composed of, for example, an organic fluorescent substance using polyvinyltoluene as a base material, between a scintillator composed of a fluoride single crystal, such as a Ce-containing LiCaAlF6 crystal, and a photodetector having a light entrance window material composed of a transparent glass material such as borosilicate glass. In the radiation detector, the peak wavelength of light emitted by the scintillator is 360 nm or less, and the peak wavelength of light after conversion by the optical conversion layer is 400 nm or more.Type: ApplicationFiled: July 20, 2011Publication date: May 2, 2013Applicants: HIROSHIMA UNIVERSITY, TOHOKU UNIVERSITY, TOKUYAMA CORPORATIONInventors: Hiromitsu Takahashi, Mitsuo Yonetani, Masayuki Matsuoka, Yasushi Fukazawa, Noriaki Kawaguchi, Kentaro Fukuda, Toshihisa Suyama, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto