Electronic Tube Or Microwave Magnetometers Patents (Class 324/250)
  • Patent number: 11756762
    Abstract: A sample holder retains a sample and can continuously rotate the sample in a single direction while the sample is exposed to a charged particle beam (CPB) or other radiation source. Typically, the CPB is strobed to produce a series of CPB images at random or arbitrary angles of rotation. The sample holder can rotate more than one complete revolution of the sample. The CPB images are used in tomographic reconstruction, and in some cases, relative rotation angles are used in the reconstruction, without input of an absolute rotation angle.
    Type: Grant
    Filed: February 3, 2022
    Date of Patent: September 12, 2023
    Assignee: FEI Company
    Inventors: Bart Jozef Janssen, Edwin Verschueren, Erik Franken
  • Patent number: 11257656
    Abstract: A sample holder retains a sample and can continuously rotate the sample in a single direction while the sample is exposed to a charged particle beam (CPB) or other radiation source. Typically, the CPB is strobed to produce a series of CPB images at random or arbitrary angles of rotation. The sample holder can rotate more than one complete revolution of the sample. The CPB images are used in tomographic reconstruction, and in some cases, relative rotation angles are used in the reconstruction, without input of an absolute rotation angle.
    Type: Grant
    Filed: April 8, 2020
    Date of Patent: February 22, 2022
    Assignee: FEI Company
    Inventors: Bart Jozef Janssen, Edwin Verschueren, Erik Franken
  • Patent number: 9702695
    Abstract: An object of the present invention is to provide an image processing apparatus that quickly and precisely measures or evaluates a distortion in a field of view and a charged particle beam apparatus. To attain the object, an image processing apparatus or the like is proposed which acquires a first image of a first area of an imaging target and a second image of a second area that is located at a different position than the first area and partially overlaps with the first area and determines the distance between a measurement point in the second image and a second part of the second image that corresponds to a particular area for a plurality of sites in the overlapping area of the first image and the second image.
    Type: Grant
    Filed: May 25, 2011
    Date of Patent: July 11, 2017
    Assignee: Hitachi High-Technologies Corporation
    Inventors: Hiroki Kawada, Osamu Inoue, Miyako Matsui, Takahiro Kawasaki, Naoshi Itabashi, Takashi Takahama, Katsumi Setoguchi, Osamu Komuro
  • Patent number: 9335345
    Abstract: A “theta” angle adjustment method for waveguide probes uses an adjustable solid parallelepiped that allows the wafer probes to be fastened to the auxiliary equipment under correcting “theta” angles and a flange holding and securing bracket that allows one waveguide section to rotate against the other. The alignment procedure requires one of both flanges to have its aligning pin holes and fastening screw threads replaced by circular (oval) holes, allowing the waveguide sections to rotate axially against each-other. The Theta angle is adjusted by repeated trial and error fastening and unfastening the securing bracket under firm pressure of the probe body against the solid support parallelepiped.
    Type: Grant
    Filed: March 18, 2013
    Date of Patent: May 10, 2016
    Inventor: Christos Tsironis
  • Patent number: 8884607
    Abstract: The present invention discloses a current measuring apparatus and associated networking apparatus, the current measuring apparatus comprising: a consumer unit comprising at least one interrupting device operative to interrupt a mains electricity supply when an excess current flows, such as a fuse box, a mains current circuit in the mains electricity supply path; and a measurement circuit that is operative to measure a voltage drop across the mains current circuit.
    Type: Grant
    Filed: December 1, 2010
    Date of Patent: November 11, 2014
    Assignee: Broadcom Corporation
    Inventors: Jonathan Ephraim David Hurwitz, Dale Stubbs
  • Patent number: 8717015
    Abstract: A magnetic field measuring system is disclosed. The magnetic field measuring system includes a substrate, a conductive well formed in the substrate, the well having a first side with a first length, a first contact electrically coupled to the conductive well at a first location of the first side, a second contact electrically coupled to the conductive well at a second location of the first side, wherein the distance between the first location and the second location is less than the first length, a stimulus circuit coupled to the first contact and the second contact, and a sensor for identifying a property indicative of the length of a current path from the first location to the second location through the conductive well.
    Type: Grant
    Filed: February 12, 2010
    Date of Patent: May 6, 2014
    Assignee: Robert Bosch GmbH
    Inventors: Chinwuba Ezekwe, Thomas Rocznik, Christoph Lang, Sam Kavusi, Martin Kramer
  • Patent number: 8680855
    Abstract: A measuring circuit system in a magnetic field measuring apparatus of the invention has an amplifier and a band-pass filter connected in sequence on an output terminal side of the TMR element, the band-pass filter is a narrow-range band-pass filter such that a peak pass frequency of the filter that is a center is a basic frequency selected from a range of 10 to 40 GHz and a band width centered around the basic frequency is a narrow range of ±0.5 to ±4 GHz; and with the measuring circuit system, an S/N ratio (SNR) of 3 dB or greater is obtained, the SNR being defined by a ratio of an amplitude S of a high-frequency generated signal induced by the TMR element to a total noise N that is a sum of a head noise generated by the TMR element and a circuit noise generated by the amplifier. With such a configuration, an in-plane high-frequency magnetic field generated by a microwave-assisted magnetic head is reliably and precisely measured.
    Type: Grant
    Filed: December 26, 2012
    Date of Patent: March 25, 2014
    Assignee: TDK Corporation
    Inventors: Isamu Sato, Hiroshi Ikeda, Mikio Matsuzaki, Tetsuya Roppongi, Noboru Yamanaka, Tsutomu Aoyama
  • Patent number: 8493057
    Abstract: A detector detects an electromagnetic wave having a frequency of 0.01 THz?f?100 THz and transmitted through a device under test (DUT). A changer changes a relative position of an intersection of an optical path of the electromagnetic wave and the DUT, with respect to the DUT. A deriver derives a characteristic value of the electromagnetic wave based on a detection result of the detector, while the characteristic value is associated with an assumed relative position, which is the relative position if the electromagnetic wave is not refracted by the DUT. A corrector changes the assumed relative position to an actual relative position, which is the relative position if the refraction of the electromagnetic wave by the DUT is considered. A corrected deriver derives the characteristic value associated with a predetermined relative position based on an output from the corrector.
    Type: Grant
    Filed: March 25, 2010
    Date of Patent: July 23, 2013
    Assignee: Advantest Corporation
    Inventors: Shigeki Nishina, Motoki Imamura, Akiyoshi Irisawa, Tomoyu Yamashita, Eiji Kato, Kodo Kawase
  • Patent number: 8461834
    Abstract: A magneto-impedance sensor element is formed in a planar type structure in which an amorphous wire is incorporated in a substrate. The magneto-impedance sensor element includes a nonmagnetic substrate, an amorphous wire arranged in an aligning direction of a planar pattern that forms a detecting coil, a spiral detecting coil formed of a planar pattern and a cubic pattern on an outer periphery of the amorphous wire, a planar insulating portion that insulates the planar pattern from the amorphous wire, a wire fixing portion to fix the amorphous wire on an upper surface of the planar insulating portion, and a cubic insulating portion that insulates the cubic pattern from the amorphous wire.
    Type: Grant
    Filed: February 27, 2009
    Date of Patent: June 11, 2013
    Assignee: Aichi Steel Corporation
    Inventors: Yoshinobu Honkura, Michiharu Yamamoto, Katsuhiko Nishihata
  • Patent number: 8446156
    Abstract: The invention provides a method and apparatus for the analysis of rocks and rock fragments. A method for the analysis of a rock fragment including: feeding the rock fragment to a microwave irradiation zone of microwave energy generated by a microwave source; gauging energy absorbed by the rock fragment; and correlating rate of change of the gauged energy absorbed by the rock fragment with compositional characteristics of the rock fragment.
    Type: Grant
    Filed: August 10, 2007
    Date of Patent: May 21, 2013
    Assignee: The University of Queensland
    Inventor: Robert D. Morrison
  • Patent number: 8358127
    Abstract: A measuring circuit system in a magnetic field measuring apparatus of the invention has an amplifier and a band-pass filter connected in sequence on an output terminal side of the TMR element, the band-pass filter is a narrow-range band-pass filter such that a peak pass frequency of the filter that is a center is a basic frequency selected from a range of 10 to 40 GHz and a band width centered around the basic frequency is a narrow range of ±0.5 to ±4 GHz; and with the measuring circuit system, an SIN ratio (SNR) of 3 dB or greater is obtained, the SNR being defined by a ratio of an amplitude S of a high-frequency generated signal induced by the TMR element to a total noise N that is a sum of a head noise generated by the TMR element and a circuit noise generated by the amplifier. With such a configuration, an in-plane high-frequency magnetic field generated by a microwave-assisted magnetic head is reliably and precisely measured.
    Type: Grant
    Filed: April 7, 2010
    Date of Patent: January 22, 2013
    Assignee: TDK Corporation
    Inventors: Isamu Sato, Hiroshi Ikeda, Mikio Matsuzaki, Tetsuya Roppongi, Noboru Yamanaka, Tsutomu Aoyama
  • Publication number: 20110248710
    Abstract: A measuring circuit system in a magnetic field measuring apparatus of the invention has an amplifier and a band-pass filter connected in sequence on an output terminal side of the TMR element, the band-pass filter is a narrow-range band-pass filter such that a peak pass frequency of the filter that is a center is a basic frequency selected from a range of 10 to 40 GHz and a band width centered around the basic frequency is a narrow range of ±0.5 to ±4 GHz; and with the measuring circuit system, an SIN ratio (SNR) of 3 dB or greater is obtained, the SNR being defined by a ratio of an amplitude S of a high-frequency generated signal induced by the TMR element to a total noise N that is a sum of a head noise generated by the TMR element and a circuit noise generated by the amplifier. With such a configuration, an in-plane high-frequency magnetic field generated by a microwave-assisted magnetic head is reliably and precisely measured.
    Type: Application
    Filed: April 7, 2010
    Publication date: October 13, 2011
    Applicant: TDK CORPORATION
    Inventors: Isamu SATO, Hiroshi Ikeda, Mikio Matsuzaki, Tetsuya Roppongi, Noboru Yamanaka, Tsutomu Aoyama
  • Patent number: 6927572
    Abstract: A method for compensation of dynamic error signals of a chopped Hall sensor that comprises at least one Hall sensor element comprising a plurality of terminal pairs for impressing an excitation current through the Hall sensor element and for taking a Hall voltage. The terminal pairs for impressing the excitation current and for taking the Hall voltage are switched in a first and/or second rotational sense. In order to compensate dynamic error signals caused by the switching, the Hall voltages taken at the terminal pairs when switching in the first rotational sense are supplied to a summation and/or averaging analysis unit together with the Hall voltages taken at the terminal pairs when switching in the second rotational sense.
    Type: Grant
    Filed: February 4, 2003
    Date of Patent: August 9, 2005
    Assignee: Infineon Technologies, AG
    Inventor: Mario Motz
  • Patent number: 6853186
    Abstract: A magnetic field sensor relies on variations in permeability of magnetic material to detect an external field. An exemplary magnetic field sensor includes a magnetic material and two or more conductors, at least one of which is connected to an electrical energy source. Current flowing through at least one of the conductors establishes a magnetic field in die magnetic material at a magnitude at which there is a generally linear relationship between the magnetic field and the permeability of the material. An external field to be sensed influences the permeability of the material. Sensing variations in the permeability of the magnetic material allows the external magnetic field to be sensed.
    Type: Grant
    Filed: January 15, 2003
    Date of Patent: February 8, 2005
    Assignee: National University of Singapore
    Inventor: Xiaoping Li
  • Patent number: 6801136
    Abstract: A method for reducing noise in borehole electromagnetic telemetry systems in which a signal receiver is positioned at a distance from a drill site borehole at which the signal receiver couples strongly to a signal from a signal transmitter disposed in the borehole and weakly to drill site noise emanating from the drill borehole, a noise receiver is positioned at a distance from the drill site borehole at which the noise receiver couples substantially only to magnetotelluric and/or drill site noise, the contributions of the magnetotelluric noise and drill site noise are determined, and subtracted from the signal received by the signal receiver, resulting in a reduced noise signal.
    Type: Grant
    Filed: October 2, 2000
    Date of Patent: October 5, 2004
    Assignee: Gas Research Institute
    Inventors: William L. Goodman, Mark Sweeny
  • Patent number: 6744249
    Abstract: A method and instrument for measuring, with a high spatial resolution, a magnetic or electric field that varies repeatedly at high speed. An electron beam is deflected by passage through a magnetic or electric field to be measured and is allowed to pass through a deflection electrode to thereby be deflected in a direction perpendicular to the magnetic or electric field to be measured. A track of the deflected electron beam is detected by a two-dimensional sensor, and a waveform or pattern is displayed wherein a time base and an axis of the magnetic field to be measured are orthogonal to each other.
    Type: Grant
    Filed: May 14, 2002
    Date of Patent: June 1, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Hiroshi Suzuki, Tomokazu Shimakura, Kimio Nakamura
  • Publication number: 20030042899
    Abstract: A method and instrument for measuring, with a high spatial resolution, a magnetic or electric field that varies repeatedly at high speed. An electron beam is deflected by passage through a magnetic or electric field to be measured and is allowed to pass through a deflection electrode to thereby be deflected in a direction perpendicular to the magnetic or electric field to be measured. A track of the deflected electron beam is detected by a two-dimensional sensor, and a waveform or pattern is displayed wherein a time base and an axis of the magnetic field to be measured are orthogonal to each other.
    Type: Application
    Filed: May 14, 2002
    Publication date: March 6, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Hiroshi Suzuki, Tomokazu Shimakura, Kimio Nakamura
  • Patent number: 6516281
    Abstract: A system, method, and computer program product are provided for scanning objects such as computer chips. A near-field scanning Single Electron Transistor (SET) is used to detect features of the object. In particular, the SET detects variations in an electric field surrounding or emanating from the object. The variation in the field may be associated with an irregularity in the object, such as an open in the circuitry of a chip. In the case of a chip or a multi-chip module, a voltage is applied to the line containing the suspected open. If an actual open is present, the open will be manifested in an irregularity in the electric field associated with the line. The SET detects the irregularity in the field. For the SET to operate, a sufficiently cold operating temperature is maintained for the SET. A very low (cryogenic) temperature allows the use of a larger, more sensitive SET. Scanning SETs are known in the literature, but in such systems the object to be scanned must also be at cryogenic temperatures.
    Type: Grant
    Filed: December 10, 1999
    Date of Patent: February 4, 2003
    Assignee: University of Maryland
    Inventors: Frederick C. Wellstood, Matthew Edward Kenyon, Christopher J. Lobb
  • Patent number: 6344743
    Abstract: The invention uniquely avails of Fourier analytical principles for determining the distribution of a magnetic field in a one-dimensional (linear), two-dimensional (planar) or three-dimensional (spatial) region of interest. According to many embodiments, integrating sensor apparatus having an associated length is inventively implemented so as to measure the magnetic field amplitude value for each of two or more different points. Alternating current is applied at at least one high frequency whereby, for each such frequency, the associated wavelength corresponds to some multiple of the sensor's length. Coiled around the sensor is/are one or more solenoids which is/are configured so as to establish a standing wave along the sensor's length. Inventive adaptation of the sensor's integrating function basically entails regarding a Fourier-type harmonic bias function as being consequential of the standing wave.
    Type: Grant
    Filed: March 5, 1999
    Date of Patent: February 5, 2002
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: John J. Holmes, John F. Scarzello
  • Patent number: 5811971
    Abstract: In a magnetic field sensing method in accordance with the invention of the present application, a magnetic sensor comprising a conductor and at least one magnetic material provided on any of the surfaces of this conductor, is employed. This magnetic sensor is disposed in the vicinity of an external magnetic field which is to be sensed, and by means of supplying a high frequency current to this conductor, the impedance of the conductor changes in accordance with the external magnetic field, and based on this, the external magnetic field is sensed.
    Type: Grant
    Filed: January 29, 1996
    Date of Patent: September 22, 1998
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Masakatsu Senda, Osamu Ishii, Yasuhiro Koshimoto, Tomoyuki Toshima
  • Patent number: 5734267
    Abstract: In a magnetic field sensing method in accordance with the invention of the present application, a magnetic sensor comprising a conductor and at least one magnetic material provided on any of the surfaces of this conductor, is employed. This magnetic sensor is disposed in the vicinity of an external magnetic field which is to be sensed, and by means of supplying a high frequency current to this conductor, the impedance of the conductor changes in accordance with the external magnetic field, and based on this, the external magnetic field is sensed.
    Type: Grant
    Filed: January 29, 1996
    Date of Patent: March 31, 1998
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Masakatsu Senda, Osamu Ishii, Yasuhiro Koshimoto, Tomoyuki Toshima
  • Patent number: 5705926
    Abstract: In a magnetic field sensing method in accordance with the invention of the present application, a magnetic sensor comprising a conductor and at least one magnetic material provided on any of the surfaces of this conductor, is employed. This magnetic sensor is disposed in the vicinity of an external magnetic field which is to be sensed, and by means of supplying a high frequency current to this conductor, the impedance of the conductor changes in accordance with the external magnetic field, and based on this, the external magnetic field is sensed.
    Type: Grant
    Filed: April 12, 1996
    Date of Patent: January 6, 1998
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Masakatsu Senda, Osamu Ishii, Yasuhiro Koshimoto, Tomoyuki Toshima
  • Patent number: 5691645
    Abstract: A process for determining the intrinsic magnetic permeability of elongated ferromagnetic elements and the electromagnetic properties of composites using such elements are disclosed. According to the process, an annular core or torus is produced, which torus is wound with ferromagnetic elements. The core is placed in a coaxial line, the properties of the torus are measured, and permeability of the elements and the properties of an equivalent composite for a given polarization are deduced from such measurement. Particular utility is found in the area of study of composite charges for use at microwave frequencies.
    Type: Grant
    Filed: July 31, 1995
    Date of Patent: November 25, 1997
    Assignee: Commissariat a L'Energie Atomique
    Inventors: Olivier Acher, Pierre Marie Jacquart, Alfred Schaal
  • Patent number: 5666053
    Abstract: A charged particle beam is transmitted through a specimen for producing an irregular pattern as a first image. Further, a magnetic field to be measured is arranged in space where a charged particle beam is passed between the specimen and an image plane thereby to produce a second image having an irregular pattern as in the foregoing case. The first image and the second image are processed to produce the deflection angle of the charged particle beam due to the magnetic field. This deflection angle is extracted from the entire positions of a cross section of the space where measurement is desired, thereby constructing projection data of a magnetic field by a charged particle beam. Furthermore, the magnetic field to be measured is rotated and the above-mentioned processing is performed from each direction to construct projection data. The projection data thus obtained and the computer tomography technique are used to determine a magnetic field at each point in space.
    Type: Grant
    Filed: February 21, 1995
    Date of Patent: September 9, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Hiroshi Suzuki, Hiroyuki Shinada, Katsuhiro Kuroda, Yusuke Yajima, Yoshio Takahashi, Hideo Saito, Masato Nakajima
  • Patent number: 5572122
    Abstract: An apparatus for measuring an electromagnetic field distribution using a focused electron beam can measure the electromagnetic field distribution in a specimen with high resolution and high reliability. A focused electron beam radiation system irradiates a specimen with a focused electron beam. A specimen tilt mechanism tilts a specimen by 180.degree. about a tilt axis that is perpendicular to the optical axis of the focused electron beam. An electron beam position detector measures the direction and quantity of the deflection given to the focused electron beam when it is transmitted through the specimen.
    Type: Grant
    Filed: October 26, 1993
    Date of Patent: November 5, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Yusuke Yajima, Yoshio Takahashi, Masakazu Ichikawa, Shigeyuki Hosoki
  • Patent number: 5420100
    Abstract: A planar SQUID magnetometer for detection and measurement of an applied magnetic flux is disclosed wherein a planar microwave-resonant element overlaps a Josephson device incorporated in a high-T.sub.c superconducting, thin-film SQUID device, thereby providing inductive coupling between the planar microwave-resonant element and the SQUID device. When the microwave-resonant element is excited by incident high-frequency microwave radiation, the intensity of reflected microwave radiation varies in response to a magnetic flux applied to the SQUID device in accordance with non-linear oscillatory behavior of the microwave-resonant element due to inductive loading by the SQUID device. The microwave-resonant element and the SQUID device are preferably fabricated photolithographically on a single substrate.
    Type: Grant
    Filed: April 5, 1991
    Date of Patent: May 30, 1995
    Assignee: Northeastern University
    Inventors: Carmine Vittoria, Allan Widom, Yizhou Huang, Hoton How
  • Patent number: 5365391
    Abstract: A distributed-constant circuit type magnetic field detector which includes a magnetic member whose permeability varies with changes in a magnetic field applied thereto disposed at a point where a magnetic field is produced in a distributed-constant circuit excited with an electromagnetic wave and a detector for detecting a change in electromagnetic field distribution in the distributed-constant circuit produced by a variation in permeability of the magnetic member upon application thereto of a magnetic field to be detected.
    Type: Grant
    Filed: February 27, 1992
    Date of Patent: November 15, 1994
    Assignee: Sony Corporation
    Inventors: Yasunari Sugiyama, Kiyoshi Kagawa, Masatoshi Hayakawa, Hiroyuki Ohmori
  • Patent number: 5315233
    Abstract: In order to take into account the effect of load resistance applied to an electromagnetic field in analyzing an electromagnetic wave oscillator, the present invention arranges a resistance equivalent to the load resistance in the analytical region, and converts a voltage applied to the load and the current flowing therein into an electric field component and a magnetic field component to analyze the electromagnetic field distribution of the entire analytical region. The motion of an electrical charge is thus analyzed taking into account a force applied to the electric charge by the electromagnetic field distribution. This compound analysis of both the electric charge motion and the electromagnetic field is alternately and repeatedly performed.
    Type: Grant
    Filed: May 14, 1991
    Date of Patent: May 24, 1994
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kazuyuki Sakiyama, Akira Ahagon, Hidetoshi Kotera, Hiromi Kita
  • Patent number: 5111141
    Abstract: A magnetic field measuring apparatus measures the magnetic field intensity of a magnetic field created by a sample magnetic head by passing a finely focussed charged particle beam through the magnetic field and by measuring the deflection of the charged particle beam caused by the deflecting action of the magnetic field on the charged particle beam. The path of the charged particle beam (the sample magnetic head) is shifted stepwise toward the sample magnetic head (the path of the charged particle beam) until the charged particle impinges on the surface of the sample magnetic head. Upon the detection of the impingement of the charged particle beam on the surface of the sample magnetic head, the path of the charged particle beam (the sample magnetic head) is put one step back so that the path of the charged particle beam extends as close as possible to the surface of the sample magnetic head for accurate magnetic field intensity measurements.
    Type: Grant
    Filed: October 31, 1990
    Date of Patent: May 5, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Satoru Fukuhara, Hiroyuki Shinada, Shigemitsu Seitoh
  • Patent number: 5075623
    Abstract: The present invention relates to a method for measuring three-dimensional spatial magnetic field distributions used particularly in measuring the magnetic field distribution in a small spatial region such as a leakage magnetic field of a magnetic head and the object thereof is a measuring method capable of measuring a high frequency magnetic field in the small spatial region with a high precision.
    Type: Grant
    Filed: April 12, 1990
    Date of Patent: December 24, 1991
    Assignee: Alps Electric Co., Ltd.
    Inventors: Jinichi Matsuda, Yasuyuki Kondoh, Koichi Mukasa, Akihiro Inada, Masahiro Iizuka, Kinya Aoyagi
  • Patent number: 4906607
    Abstract: A sensor and method for indicating the presence of a low magnetic field using high critical temperature superconductor ceramic material is comprised of a sensing element consisting essentially of the high critical temperature superconductor ceramic material without the need for further processing. The sensing element is cooled to a temperature below the critical temperature of the superconductor material, whereby the sensing element becomes superconducting. Electromagnetic energy is applied to the sensing element, a first portion of the energy being absorbed by the sensing element. The amount of the energy absorbed by the sensing element is detected. The sensing element is modulated to provide a reference signal and is biased to a predetermined absorption reference value, whereby a magnetic field of about 10.sup.
    Type: Grant
    Filed: April 6, 1988
    Date of Patent: March 6, 1990
    Assignee: Drexel University
    Inventor: Som Dev Tyagi
  • Patent number: 4803430
    Abstract: A magnetic/electric field measuring device is disclosed, which is provided with an electron beam generator for generating an electron beam finely focused; a sample table, on which a sample is placed; electron beam deflectors for sweeping the electron beam two-dimensionally along an end surface of the sample; two-dimensional semiconductor position detection element using a photodiode for detecting the incident position of the electron beam, which has passed along the end surface of the sample; and a display section for displaying the position signal coming from said two-dimensional semiconductor position detection element in synchronism with a scan signal for the electron beam.
    Type: Grant
    Filed: February 8, 1988
    Date of Patent: February 7, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Hiroyuki Shinada, Hideo Todokoro, Satoru Fukuhara
  • Patent number: 4465974
    Abstract: Bodies of a ferrimagnetic material are disposed within small cavities provided in a magnetometer. The magnetometer is initially calibrated utilizing an electromagnet to produce an applied magnetic field of either known field strength, H.sub.DC, or known field distribution. Radio frequency energy is fed equally to each cavity and each material and results in resonance frequency output signals which may be coupled to a visual display. When the calibrating magnetic field is of known uniform strength, H.sub.DC, the orientation of the bodies is changed until each of the resonance signals have a frequency substantially given by f.sub.c =.gamma.H.sub.DC where .gamma.=2.8 MHz/oersted. When the calibrating magnetic field has a known field distribution the orientation of bodies is changed until such resonance signals have frequencies related to one another in accordance with the relative magnetic field strengths passing through the cavities.
    Type: Grant
    Filed: May 7, 1982
    Date of Patent: August 14, 1984
    Assignee: Raytheon Company
    Inventor: Richard A. Sparks
  • Patent number: 4414509
    Abstract: A low energy electron beam magnetometer that utilizes near-monoenergetic electrons thereby reducing errors due to electron energy spread and electron nonuniform angular distribution. In a first embodiment of the invention (FIGS. 3 and 4) atoms in an atomic beam 30 of an inert gas are excited to a Rydberg state (lasers 32, 33 and 34) and then electrons of near zero energy are detached from the Rydberg atoms (gas chamber 35 ). The near zero energy electrons are then accelerated by an electric field V.sub.acc to form the electron beam 21. In a second embodiment of the invention (FIG. 5) a filament 42 emits electrons into an electrostatic analyzer 40 which selects electrons at a predetermined energy level within a very narrow range. These selected electrons make up the electron beam that is subjected to the magnetic field being measured.
    Type: Grant
    Filed: November 26, 1980
    Date of Patent: November 8, 1983
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Jag J. Singh, George M. Wood, Jr., Grayson H. Rayborn, Frederick A. White
  • Patent number: 4341998
    Abstract: A unidirectional magnetometer comprising at least two magnetostatic wave oscillators with resonators or delay lines, made in two portions in a magnetic material layer respectively subject to the field to be measured and to given magnetic fields of the same direction, but of opposite sense and adjacent intensities.
    Type: Grant
    Filed: February 25, 1980
    Date of Patent: July 27, 1982
    Assignee: Thomson-CSF
    Inventors: Jean P. Castera, Pierre Hartemann
  • Patent number: 4340861
    Abstract: Bodies of a ferrimagnetic material are disposed within small cavities provided in a magnetometer. The magnetometer is initially calibrated utilizing an electromagnet to produce an applied magnetic field of either known field strength, H.sub.DC, or known field distribution. Radio frequency energy is fed equally to each cavity and each material and results in resonance frequency output signals which may be coupled to a visual display. When the calibrating magnetic field is of known uniform strength, H.sub.DC, the orientation of the bodies is changed until each of the resonance signals have a frequency substantially given by f.sub.c =.gamma.H.sub.DC where .gamma.=2.8 MHz/oersted. When the calibrating magnetic field has a known field distribution the orientation of bodies is changed until such resonance signals have frequencies related to one another in accordance with the relative magnetic field strengths passing through the cavities.
    Type: Grant
    Filed: March 3, 1980
    Date of Patent: July 20, 1982
    Assignee: Raytheon Company
    Inventor: Richard A. Sparks