Patents by Inventor Akira Yoshikawa

Akira Yoshikawa 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).

  • Patent number: 8809797
    Abstract: 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: Grant
    Filed: December 15, 2011
    Date of Patent: August 19, 2014
    Assignees: Tokuyama Corporation, Tohoku University
    Inventors: Hisanori Yamane, Tetsuya Kawano, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto, Kentaro Fukuda, Noriaki Kawaguchi
  • Patent number: 8795822
    Abstract: [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: Grant
    Filed: November 1, 2011
    Date of Patent: August 5, 2014
    Assignees: Tokuyama Corporation, Tohoku University
    Inventors: Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
  • Publication number: 20140203211
    Abstract: An afterglow property of cesium iodide: thallium (CsI:Tl), in which CsI is a host material and doped with thallium, is improved. It is possible to improve the afterglow property of a scintillator by doping a crystal material including CsI (cesium iodide), as a host material, and thallium (Tl), as a luminescent center, with bismuth (Bi).
    Type: Application
    Filed: August 17, 2012
    Publication date: July 24, 2014
    Applicants: NIHON KESSHO KOGAKU CO., LTD., TOHOKU UNIVERSITY
    Inventors: Daisuke Totsuka, Susumu Matsumoto, Akira Yoshikawa, Takayuki Yanagida
  • Patent number: 8729482
    Abstract: Provided is a radiation detector with improved n/? discrimination and usable even under high counting rate conditions with a reduced load on a signal-processing system. The detector capable of distinguishing neutron and gamma-ray events includes: a scintillator; an optical filter; a first photodetector to which a first part of light emitted from the scintillator is introduced via the optical filter; and a second photodetector to which a second part of light emitted from the scintillator is introduced not via the optical filter, wherein, for a set of two wavelengths A and (A+B) nm, the scintillator emits at least a light of A nm and a light of (A+B) nm when irradiated by gamma-ray, and emits a light of A nm and does not emit a light of (A+B) nm when irradiated by neutrons; and the optical filter blocks the light of A nm and transmits the light of (A+B) nm.
    Type: Grant
    Filed: February 6, 2013
    Date of Patent: May 20, 2014
    Assignees: Tokuyama Corporation, National University Corporation Nagoya University
    Inventors: Kenichi Watanabe, Yoshihiko Takahashi, Atsushi Yamazaki, Akira Uritani, Tetsuo Iguchi, Kentaro Fukuda, Noriaki Kawaguchi, Sumito Ishizu, Akira Yoshikawa, Takayuki Yanagida
  • Patent number: 8642972
    Abstract: [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: Grant
    Filed: April 26, 2011
    Date of Patent: February 4, 2014
    Assignees: Tokuyama Corporation, Tohoku University
    Inventors: Kentaro Fukuda, Sumito Ishizu, Noriaki Kawaguchi, Toshihisa Suyama, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota
  • Publication number: 20140021355
    Abstract: 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: Application
    Filed: April 2, 2012
    Publication date: January 23, 2014
    Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATION
    Inventors: Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota
  • Publication number: 20130327946
    Abstract: 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: Application
    Filed: February 24, 2012
    Publication date: December 12, 2013
    Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATION
    Inventors: Noriaki Kawaguchi, Kentaro Fukuda, Toshihisa Suyama, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
  • Publication number: 20130320217
    Abstract: 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: Application
    Filed: March 8, 2012
    Publication date: December 5, 2013
    Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATION
    Inventors: Noriaki Kawaguchi, Kentaro Fukuda, Toshihisa Suyama, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
  • Publication number: 20130306874
    Abstract: The garnet-type crystal for a scintillator of the present invention is represented by General Formula (1), (2), or (3), Gd3-x-yCexREyAl5-zGazO12??(1) wherein in Formula (1), 0.0001?x?0.15, 0?y?0.1, 2<z?4.5, and RE represents at least one selected from Y, Yb, and Lu; Gd3-a-bCeaLubAl5-cGacO12??(2) wherein in Formula (2), 0.0001?a?0.15, 0.1<b?3, and 2<c?4.5; Gd3-p-qCerRE?qAl5-rGarO12??(3) wherein in Formula (3), 0.0001?p?0.15, 0.1<q?3, 1<r?4.5, and RE? represents Y or Yb.
    Type: Application
    Filed: January 27, 2012
    Publication date: November 21, 2013
    Applicants: TOHOKU TECHNO ARCH CO., LTD., FURUKAWA CO., LTD.
    Inventors: Akira Yoshikawa, Takayuki Yanagida, Kei Kamada, Hiroki Sato, Kosuke Tsutsumi, Takanori Endo, Shigeki Ito
  • Publication number: 20130264482
    Abstract: 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: Application
    Filed: December 15, 2011
    Publication date: October 10, 2013
    Inventors: Hisanori Yamane, Tetsuya Kawano, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto, Kentaro Fukuda, Noriaki Kawaguchi
  • Publication number: 20130240776
    Abstract: An oxide material having a langasite-type structure having a desired surface condition and a desired outer shape is obtained stably. By adding at least one selected from the group consisting of Ir, Pt, Au, and Rh to a raw material which is a composition used for producing a desired oxide material as an additive element, it is possible to control the wettability between a die portion at a bottom end of a crucible and a melt of the raw material, thereby implementing stable production of the oxide material while controlling the wetting and spread of the melt of the raw material leaked out through a hole of the crucible.
    Type: Application
    Filed: October 12, 2011
    Publication date: September 19, 2013
    Applicant: TDK CORPORATION
    Inventors: Ko Onodera, Kazushige Tohta, Masato Sato, Akira Yoshikawa, Yuui Yokota
  • Publication number: 20130214203
    Abstract: [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: Application
    Filed: November 1, 2011
    Publication date: August 22, 2013
    Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATION
    Inventors: Sumito Ishizu, Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
  • Publication number: 20130183509
    Abstract: [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: Application
    Filed: November 1, 2011
    Publication date: July 18, 2013
    Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATION
    Inventors: Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
  • Publication number: 20130181137
    Abstract: 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: Application
    Filed: May 18, 2011
    Publication date: July 18, 2013
    Inventors: Kenichi Watanabe, Atsushi Yamazaki, Akira Uritani, Yoshiyuki Kondo, Tetsuo Iguchi, Noriaki Kawaguchi, Kentaro Fukuda, Toshihisa Suyama, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota
  • Publication number: 20130168561
    Abstract: [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: Application
    Filed: November 1, 2011
    Publication date: July 4, 2013
    Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATION
    Inventors: Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
  • Publication number: 20130161519
    Abstract: [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: Application
    Filed: November 1, 2011
    Publication date: June 27, 2013
    Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATION
    Inventors: Sumito Ishizu, Kentaro Fukuda, Noriaki Kawaguchi, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
  • Publication number: 20130112885
    Abstract: [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: Application
    Filed: July 20, 2011
    Publication date: May 9, 2013
    Applicants: HIROSHIMA UNIVERSITY, TOHOKU UNIVERSITY, TOKUYAMA CORPORATION
    Inventors: Hiromitsu Takahashi, Mitsuo Yonetani, Masayuki Matsuoka, Yasushi Fukazawa, Noriaki Kawaguchi, Kentaro Fukuda, Toshihisa Suyama, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
  • Publication number: 20130105707
    Abstract: [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: Application
    Filed: July 20, 2011
    Publication date: May 2, 2013
    Applicants: HIROSHIMA UNIVERSITY, TOHOKU UNIVERSITY, TOKUYAMA CORPORATION
    Inventors: Hiromitsu Takahashi, Mitsuo Yonetani, Masayuki Matsuoka, Yasushi Fukazawa, Noriaki Kawaguchi, Kentaro Fukuda, Toshihisa Suyama, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota, Yutaka Fujimoto
  • Patent number: 8405034
    Abstract: A neutron measurement apparatus 1A includes a neutron detection unit 10, a photodetection unit 20 that detects scintillation light emitted from the neutron detection unit 10, a light guide optical system 15 that guides the scintillation light from the neutron detection unit 10 to the photodetection unit 20, and a shielding member 30 which is located between the neutron detection unit 10 and the photodetection unit 20 for shielding radiation passing in a direction toward the photodetection unit 20. Further, a scintillator formed of a lithium glass material in which PrF3 is doped to a glass material 20Al(PO3)3-80LiF is used as a neutron detection scintillator composing the neutron detection unit 10. Thereby, the neutron detection scintillator and the neutron measurement apparatus which are capable of suitably performing neutron measurement such as measurement of scattered neutrons from an implosion plasma can be realized.
    Type: Grant
    Filed: April 27, 2010
    Date of Patent: March 26, 2013
    Assignees: Osaka University, TOKAI UNIVERSITY Educational System
    Inventors: Hiroshi Azechi, Nobuhiko Sarukura, Yasunobu Arikawa, Mitsuo Nakai, Hirofumi Kan, Takahiro Murata, Toshihisa Suyama, Shigeru Fujino, Yoshiyuki Usuki, Hideki Yoshida, Akira Yoshikawa
  • Publication number: 20130043402
    Abstract: [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: Application
    Filed: April 26, 2011
    Publication date: February 21, 2013
    Applicants: TOHOKU UNIVERSITY, TOKUYAMA CORPORATION
    Inventors: Kentaro Fukuda, Sumito Ishizu, Noriaki Kawaguchi, Toshihisa Suyama, Akira Yoshikawa, Takayuki Yanagida, Yui Yokota