Patents by Inventor Takayuki Ohmura

Takayuki Ohmura 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).

  • Publication number: 20090224666
    Abstract: The present invention relates to a photomultiplier having a fine structure capable of realizing high multiplication efficiency. The photomultiplier comprises a housing whose inside is maintained vacuum, and, on a device mounting surface which is a part of an inner wall surface defining an internal space of the housing, a photocathode serving as a reflection type photocathode, an electron-multiplier section, an anode, and a voltage distributing section are disposed integrally. In particular, the electron-multiplier section is constituted by dynodes at multiple stages cascade-multiplying photoelectrons from the photocathode, and the voltage distributing section, which applies corresponding voltages to the dynodes at the respective stages respectively, is on the same surface together with the electron-multiplier section.
    Type: Application
    Filed: June 1, 2006
    Publication date: September 10, 2009
    Inventors: Hiroyuki Kyushima, Hideki Shimoi, Hiroyuki Sugiyama, Hitoshi Kishita, Suenori Kimura, Yuji Masuda, Takayuki Ohmura
  • Publication number: 20090218944
    Abstract: The present invention relates to a photomultiplier having a fine configuration capable of realizing stable detection accuracy. The photomultiplier has a housing whose inside is maintained vacuum, and a photocathode, an electron-multiplier section, and an anode are disposed in the housing. In particular, one or more control electrodes disposed in an internal space of the housing which surrounds the electron-multiplier section and the anode are electrically connected via one or more connection parts extending from an electron emission terminal of the electron-multiplier section.
    Type: Application
    Filed: June 1, 2006
    Publication date: September 3, 2009
    Inventors: Hiroyuki Kyushima, Hideki Shimoi, Hiroyuki Sugiyama, Hitosha Kishita, Suenori Kimura, Yuji Masuda, Takayuki Ohmura
  • Publication number: 20090212699
    Abstract: The present invention relates to a photomultiplier that realizes a significant improvement of response time characteristics by a structure enabling mass production. The photomultiplier comprises a sealed container, and, in the sealed container, a photocathode, an electron multiplier section, and an anode are respectively disposed. The electron multiplier section includes multiple stages of dynode units, and each of the multiple stages of dynode units is fixed with one end of the associated dynode pin while being electrically connected thereto. In particular, the dynode pin, whose one ends are fixed to the multiple stages of dynode units, are held within an effective region of the electron multiplier section contributing to secondary electron multiplication, when the electron multiplier section is viewed from the photocathode side.
    Type: Application
    Filed: February 19, 2009
    Publication date: August 27, 2009
    Applicant: HAMAMATSU PHOTONICS K.K.
    Inventors: Takayuki Ohmura, Hiroyuki Kyushima, Hideki Shimoi, Tsuyoshi Kodama
  • Publication number: 20090045741
    Abstract: The present invention relates to a photomultiplier having a fine structure capable of realizing high detection accuracy by effectively suppressing cross talk among electron-multiplier channels. The photomultiplier comprises a housing whose inside is maintained vacuum, and, in the housing, a photocathode, an electron-multiplier section, and anodes are disposed. The electron-multiplier section has groove portions for cascade-multiplying photoelectrons as electron-multiplier channels, and the anodes are constituted by channel electrodes corresponding to the groove portions respectively defined by wall parts. In particular, at least parts of the respective channel electrodes are located in spaces sandwiched between pairs of wall parts defining the corresponding groove portions.
    Type: Application
    Filed: June 1, 2006
    Publication date: February 19, 2009
    Inventors: Hiroyuki Kyushima, Hideki Shimoi, Hiroyuki Sugiyama, Hitoshi Kishita, Suenori Kimura, Yuji Masuda, Takayuki Ohmura
  • Patent number: 7489077
    Abstract: A glass container has a faceplate, a side tube, and a bottom. A photocathode is formed on the inner side of the faceplate. The glass container includes a partitioning wall, a shield electrode, a first dynode, a second dynode, a dynode array, and an anode. The partitioning wall has a cross shape to divide an electron focusing space into four space segments. The shield electrode is provided to shield the second dynode from the photocathode. A Venetian blind type of dynodes is provided as the dynode array. The first dynode, the second dynode, the dynode array, and the anode are maintained at the potential which is higher than that of the photocathode. Electrons emitted from the photocathode in response to incident light thereon efficiently impinge on the dynodes regardless of where the electrons are emitted. The electrons are multiplied and then detected by the anode.
    Type: Grant
    Filed: March 24, 2004
    Date of Patent: February 10, 2009
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Suenori Kimura, Takayuki Ohmura, Teruhiko Yamaguchi, Masuo Ito
  • Patent number: 7449834
    Abstract: The present invention relates to a photomultiplier that realizes significant improvement of response time properties with a structure enabling mass production. The photomultiplier comprises an electron multiplier section for cascade-multiplying photoelectrons emitted from said photocathode. The electron multiplier has a structure holding at least two dynode sets while sandwiching the tube axis of a sealed container in this the electron multiplier is housed. In particular, the first dynodes respectively belonging to the two dynode sets are arranged such that their back surfaces opposing respective secondary electron emitting surfaces face each other while sandwiching the tube axis. In this arrangement, because each first dynode itself is positioned near the tube axis, the efficiency of collection of photoelectrons arriving at the periphery of the first dynode is improved significantly.
    Type: Grant
    Filed: November 8, 2006
    Date of Patent: November 11, 2008
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Takayuki Ohmura, Suenori Kimura
  • Patent number: 7427835
    Abstract: The present invention relates to a photomultiplier having a structure that enables to perform high gain and satisfy higher required characteristics. In the photomultiplier, an electron-multiplying unit accommodated in a sealed container comprises a focusing electrode, an accelerating electrode, a dynode unit, and an anode. Particularly, at least the accelerating electrode and dynode unit are held unitedly in a state that at least a first-stage dynode and a second-stage included in the dynode unit are opposite directly to the accelerating electrode not through a conductive material. A conventional metal disk for supporting directly dynodes which are set to the same potential as that of the first-stage dynode is not placed between the accelerating electrode and dynode unit; thus, variations of the transit time of electrons may be drastically reduced while the electrons reach from the cathode to the second-stage dynode via the first-stage dynode.
    Type: Grant
    Filed: December 6, 2005
    Date of Patent: September 23, 2008
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Takayuki Ohmura, Suenori Kimura, Masuo Ito
  • Publication number: 20080211403
    Abstract: The present invention relates to a photomultiplier having a structure that enables to perform high gain and satisfy higher required characteristics. In the photomultiplier, an electron-multiplying unit accommodated in a sealed container comprises a focusing electrode, an accelerating electrode, a dynode unit, and an anode. Particularly, at least the accelerating electrode and dynode unit are held unitedly in a state that at least a first-stage dynode and a second-stage included in the dynode unit are opposite directly to the accelerating electrode not through a conductive material. A conventional metal disk for supporting directly dynodes which are set to the same potential as that of the first-stage dynode is not placed between the accelerating electrode and dynode unit; thus, variations of the transit time of electrons may be drastically reduced while the electrons reach from the cathode to the second-stage dynode via the first-stage dynode.
    Type: Application
    Filed: May 7, 2008
    Publication date: September 4, 2008
    Inventors: Takayuki Ohmura, Suenori Kimura, Masuo Ito
  • Publication number: 20080088232
    Abstract: The present invention relates to a photomultiplier that realizes significant improvement of response time properties with a structure enabling mass production. In the sealed container, a photocathode, a dynode unit including at least one dynode set, and preferably dynode sets of two series, a focusing electrode unit arranged between the photocathode and the dynode unit are housed. The focusing electrode unit is set to the same potential as the second dynode arranged at a position where secondary electrons from said first dynode, which emits secondary electrons in response to incidence of photoelectrons, arrive, and is provided with partitioning plates partitioning the second dynode into two in a longitudinal direction of the second dynode.
    Type: Application
    Filed: November 8, 2006
    Publication date: April 17, 2008
    Inventors: Takayuki Ohmura, Teruhiko Yamaguchi
  • Publication number: 20080088234
    Abstract: The present invention relates to a photomultiplier that realizes significant improvement of response time properties with a structure enabling mass production. The photomultiplier comprises a sealed container, and, in the sealed container, a photocathode, at least one dynode set, a dynode unit including a part of insulating supporting members holding the one dynode unit, and a gain control unit are housed. The gain control unit has an insulating base plate, and the insulating base plate is integrally fixed with a control dynode and a final stage dynode that belong to each dynode set together with an anode. By the insulating base plate thus being clamped by the pair of insulating supporting members, the anode, the control dynode, and the final stage dynode constitute a part of an electron multiplier section.
    Type: Application
    Filed: November 8, 2006
    Publication date: April 17, 2008
    Inventors: Takayuki Ohmura, Teruhiko Yamaguchi
  • Publication number: 20080088233
    Abstract: The present invention relates to a photomultiplier that realizes significant improvement of response time properties with a structure enabling mass production. The photomultiplier comprises an electron multiplier section for cascade-multiplying photoelectrons emitted from said photocathode. The electron multiplier has a structure holding at least two dynode sets while sandwiching the tube axis of a sealed container in this the electron multiplier is housed. In particular, the first dynodes respectively belonging to the two dynode sets are arranged such that their back surfaces opposing respective secondary electron emitting surfaces face each other while sandwiching the tube axis. In this arrangement, because each first dynode itself is positioned near the tube axis, the efficiency of collection of photoelectrons arriving at the periphery of the first dynode is improved significantly.
    Type: Application
    Filed: November 8, 2006
    Publication date: April 17, 2008
    Inventors: Takayuki Ohmura, Suenori Kimura
  • Publication number: 20080087831
    Abstract: The present invention relates to a photomultiplier that realizes significant improvement of response time properties with a structure enabling mass production. The photomultiplier comprises a sealed container, and the sealed container includes a hollow body section, extending along a tube axis, and a faceplate. The faceplate has a light incidence surface and a light emission surface on which a photocathode is formed. In particular, the light emission surface is constituted by a flat region, and a curved-surface processed region that is positioned at a periphery of the flat region and that includes edges of the light emission surface. A surface shape of the peripheral region of the light emission surface of the faceplate is thus intentionally changed in order to adjust the angles of emission of photoelectrons from the photocathode positioned at the peripheral region.
    Type: Application
    Filed: November 8, 2006
    Publication date: April 17, 2008
    Inventors: Takayuki Ohmura, Suenori Kimura, Masuo Ito, Teruhiko Yamaguchi
  • Publication number: 20080061690
    Abstract: Therefore, use of the electron lens forming electrodes 115 and 117 flattens the potential distribution in the longitudinal direction of the first dynode 107a in front of the first dynode 107a, that is, between the dynodes 107a and 107b. As a result, both photoelectrons emitted from the peripheral edge of the cathode 3 and photoelectrons emitted from the center region of the cathode 3 travel substantially in a straight line from the first dynode 107a after being multiplied thereby to impinge on the second dynode 107b. Since this structure reduces deviation in the transit distance of photoelectrons based on the irradiated position of light on the cathode 3, the structure also reduces the cathode transit time difference (CTTD) according to the irradiated position of light and a transit time spread (TTS) when light is irradiated on the entire surface.
    Type: Application
    Filed: December 24, 2004
    Publication date: March 13, 2008
    Applicant: Hamamatsu Photonics K.K.
    Inventors: Takayuki Ohmura, Suenori Kimura, Masuo Ito
  • Publication number: 20070241677
    Abstract: The present invention relates to a photomultiplier having a configuration for improving response time characteristics. The photomultiplier comprises at least a sealed container, a photocathode, and an electron multiplier section. The electron multiplier section has an upper unit and a lower unit. The upper unit includes a focusing electrode, a mesh electrode, and a first dynode. The lower unit includes the subsequent dynodes excluding the first dynode and a pair of insulating supporting members. The length in the longitudinal direction of the first dynode is made greater than the interval between the pair of insulating supporting members. By this configuration, the sizes of the effective regions of the assigned electron multiplier channels can be set arbitrarily without being restricted by the pair of insulating supporting members.
    Type: Application
    Filed: April 13, 2007
    Publication date: October 18, 2007
    Inventors: Takayuki Ohmura, Teruhiko Yamaguchi
  • Publication number: 20070241679
    Abstract: The present invention relates to a photomultiplier having a configuration for improving response time characteristics. The photomultiplier comprises a sealed container, a photocathode, and an electron multiplier section. The electron multiplier section has an upper unit and a lower unit. The upper unit includes a focusing electrode, a mesh electrode, and a first dynode. The lower unit includes the subsequent dynodes excluding the first dynode and a pair of insulating supporting members. The second dynode, belonging to the subsequent dynodes, is provided with a notch for partitioning effective regions for two adjacent electron multiplier channels. By this configuration, a sufficient discharge withstand voltage can be secured without having to modify electron trajectories.
    Type: Application
    Filed: April 13, 2007
    Publication date: October 18, 2007
    Inventors: Takayuki Ohmura, Suenori Kimura
  • Publication number: 20070241680
    Abstract: The present invention relates to a photomultiplier having a configuration for improving response time characteristics. The photomultiplier comprises at least a sealed container, a photocathode, and an electron multiplier section. The electron multiplier section has an upper unit and a lower unit. The upper unit includes a focusing electrode, a mesh electrode, and a first dynode, among a multiple stages of dynodes, being a dynode at which the photoelectrons from the photocathode arrive. The lower unit includes the subsequent dynodes while excluding the first dynode from the multiple stages of dynodes, and a pair of insulating supporting members that clampingly hold the subsequent dynodes. The mesh electrode is positioned in an inclined state with respect to a tube axis.
    Type: Application
    Filed: April 13, 2007
    Publication date: October 18, 2007
    Inventors: Takayuki Ohmura, Suenori Kimura
  • Publication number: 20070241678
    Abstract: The present invention relates to a photomultiplier having a configuration for improving response time characteristics. The photomultiplier comprises at least a sealed container, a photocathode, and an electron multiplier section. The electron multiplier section has an upper unit and a lower unit. The upper unit includes a focusing electrode, a mesh electrode, and a first dynode. The lower unit includes the subsequent dynodes excluding the first dynode and a pair of insulating supporting members. The upper unit further includes partitioning plates for partitioning effective regions for plural electron multiplier channels that are assigned along the longitudinal direction of said first dynode in order to prevent crosstalk among the adjacent electron multiplier channels.
    Type: Application
    Filed: April 13, 2007
    Publication date: October 18, 2007
    Inventors: Takayuki Ohmura, Teruhiko Yamaguchi
  • Publication number: 20070182325
    Abstract: A glass container has a faceplate, a side tube, and a bottom. A photocathode is formed on the inner side of the faceplate. The glass container includes a partitioning wall, a shield electrode, a first dynode, a second dynode, a dynode array, and an anode. The partitioning wall has a cross shape to divide an electron focusing space into four space segments. The shield electrode is provided to shield the second dynode from the photocathode. A Venetian blind type of dynodes is provided as the dynode array. The first dynode, the second dynode, the dynode array, and the anode are maintained at the potential which is higher than that of the photocathode. Electrons emitted from the photocathode in response to incident light thereon efficiently impinge on the dynodes regardless of where the electrons are emitted. The electrons are multiplied and then detected by the anode.
    Type: Application
    Filed: March 24, 2004
    Publication date: August 9, 2007
    Applicant: HAMAMATSU PHOTONICS K.K.
    Inventors: Suenori Kimura, Takayuki Ohmura, Teruhiko Yamaguchi, Masuo Ito
  • Publication number: 20060220554
    Abstract: The present invention relates to a photomultiplier having a structure that enables to perform high gain and satisfy higher required characteristics. In the photomultiplier, an electron-multiplying unit accommodated in a sealed container comprises a focusing electrode, an accelerating electrode, a dynode unit, and an anode. Particularly, at least the accelerating electrode and dynode unit are held unitedly in a state that at least a first-stage dynode and a second-stage included in the dynode unit are opposite directly to the accelerating electrode not through a conductive material. A conventional metal disk for supporting directly dynodes which are set to the same potential as that of the first-stage dynode is not placed between the accelerating electrode and dynode unit; thus, variations of the transit time of electrons may be drastically reduced while the electrons reach from the cathode to the second-stage dynode via the first-stage dynode.
    Type: Application
    Filed: December 6, 2005
    Publication date: October 5, 2006
    Inventors: Takayuki Ohmura, Suenori Kimura, Masuo Ito
  • Patent number: 7064485
    Abstract: A glass container has a faceplate, a side tube, and a bottom. A photocathode is formed on the inner side of the faceplate. The glass container includes a first dynode, a second dynode, a screen focusing electrode, a dynode array, and an anode. The screen focusing electrode consists of a first screen, a second screen, a flat plate, and an aperture. The first screen is provided on the first dynode side of the aperture and extends across the lower end of the first dynode towards the photocathode. The second screen is provided on the second dynode side of the aperture and extends across the lower end of the second dynode towards the photocathode. A Venetian blind type is provided as the dynode array. The first dynode, the second dynode, the dynode array, and the anode are maintained at the potential which is higher than that of the photocathode. Electrons emitted from the photocathode in response to incident light thereon efficiently impinge on the dynodes regardless of where the electrons are emitted.
    Type: Grant
    Filed: March 24, 2004
    Date of Patent: June 20, 2006
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Suenori Kimura, Takayuki Ohmura, Teruhiko Yamaguchi, Masuo Ito