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Method of and apparatus for measuring properties of an object with acoustically induced electromagnetic waves

Foreign code F150008499
File No. B15-03EP2
Posted date Nov 5, 2015
Country EPO
Application number 13164257
Gazette No. 2668899
Gazette No. 2668899
Date of filing Aug 14, 2006
Gazette Date Dec 4, 2013
Gazette Date Jul 29, 2015
Priority data
  • P2005-325064 (Nov 9, 2005) JP
  • 06796418 (Aug 14, 2006) EP
Title Method of and apparatus for measuring properties of an object with acoustically induced electromagnetic waves
Abstract A measuring method and apparatus in which a measurable object (23) is irradiated with acoustically induced electromagnetic waves to measure a magnetic property from one or more characteristics selected from the group which consists of intensity, phase, and frequency characteristics of said electromagnetic waves.
The magnetic property of said measurable object (23) includes a property value for magnetization due to nuclear spin in said measurable object (23) or for acousto-magnetic resonance attributable to electron spin or nuclear spin in said measurable object (23).
Scope of claims [claim1]
1. An apparatus for measuring a property of an object (23) with acoustically induced electromagnetic waves, comprising: an anechoic chamber (22); a retainer table (24) for holding said measurable object (23) disposed in said anechoic chamber (22); an acoustic generator (25) for emitting an acoustic wave (26) towards said measurable object (23); an antenna or coil (28) for receiving electromagnetic waves generated from a part (23a) of said measurable object (23) which is irradiated with said acoustic wave (26) emitted by said acoustic generator (25); and a control, measure, and process unit (29, 30, 50, 52,60, 65, 75, 76) for driving and controlling said acoustic generator (25) and for measuring and processing said electromagnetic waves received by said antenna or coil (28), wherein the control, measure and process unit is configured to: measure a magnetic property from one or more characteristics selected from the group which consists of intensity, phase, and frequency characteristics of said electromagnetic waves, characterized in that it is further configured to determine information on nuclear or electron spin in the object (23) by determining a resonance frequency at which the strength or phase of electromagnetic waves largely varies and by scanning frequencies of sound waves to obtain a spectrum, and scan the focusing position of acoustic waves over a two-dimensional surface or three-dimensional volume of said measurable object (23) or mechanically scan said acoustic generator (25) around said measurable object (23) to scan the focusing position of acoustic waves over a two-dimensional surface or three-dimensional volume of said measurable object (23).
[claim2]
2. An apparatus according to claim 1, wherein
said acoustic generator (25) comprises a plurality of acoustic generators or a plurality of acoustic generators fixed on a concaved surface whose normal is focused on a point, whereby acoustic wave pulses generated from said acoustic generators are controlled of their mutual phase by said control, measure, and process unit so as to be focused on a desired position of said measurable object (23), and
the focusing position of acoustic waves is scanned over a two-dimensional surface or three-dimensional volume of said measurable object (23) or said acoustic generators are scanned mechanically around said measurable object (23) to scan the focusing position of acoustic waves over a two-dimensional surface or three-dimensional volume of said measurable object (23).
[claim3]
3. An apparatus according to claim 1, wherein
acoustic waves (26) with which said measurable object is irradiated are in the form of acoustic wave pulses, and
said control, measure, and process unit includes means by which electromagnetic waves received by said antenna or coil (28) are heterodyne- or phase-detected with a frequency of said acoustic waves, and means by which an electromagnetic wave signal so detected is locked in with a pulse period frequency of said acoustic wave pulses and thereby detected.
[claim4]
4. An apparatus according to claim 1, wherein
said control, measure, and process unit comprises means for causing broadband ultrashort pulses to be generated from said acoustic generator (25), and means for measuring a frequency of electromagnetic waves received by said antenna or coil (28).
[claim5]
5. An apparatus according to claim 4, wherein
said means for measuring a frequency of said electromagnetic waves comprises one or more means selected from the group which consists of a bandpass filter, a lock-in amplifier, and a spectrum analyzer.
[claim6]
6. An apparatus according to any one of claims 1 to 5, wherein
said control, measure, and process unit includes a SQUID for detecting a magnetic field.
[claim7]
7. A method of measuring a property of an object (23) with acoustically induced electromagnetic waves, comprising the steps of: irradiating a measurable object (23) with acoustic waves (26); receiving electromagnetic waves (27) generated from said measurable object (23); measuring a magnetic property from one or more characteristics selected from the group which consists of intensity, phase, and frequency characteristics of said electromagnetic waves, and characterized in that the method comprises: determining information on nuclear or electron spin in the object (23) by determining a resonance frequency at which the strength or phase of electromagnetic waves largely varies and by scanning frequencies of sound waves to obtain a spectrum, wherein a focusing position of said acoustic waves (26) is scanned over a two-dimensional surface or three-dimensional volume of said measurable object (23) or a source of emission (25) of said acoustic waves (26) is scanned mechanically around said measurable object (23) to scan the focusing position of the acoustic waves (26) over a two-dimensional surface or three-dimensional volume of said measurable object (23).
[claim8]
8. A method according to claim 7, wherein
said electromagnetic waves are measured by heterodyne or phase detection of the electromagnetic waves radiated from said measurable object (23) with a frequency of said acoustic waves as a reference signal.
[claim9]
9. A method according to claim 7, wherein
the acoustic waves (26) with which said measurable object is irradiated are in the form of acoustic wave pulses, and
said electromagnetic waves are measured by heterodyne or phase detection of electromagnetic waves radiated from said measurable object with a frequency of said pulses as a reference signal and heterodyne or phase detection of a signal resulting from said detection with a pulse frequency of said acoustic wave pulses.
[claim10]
10. A method according to any one of claims 7 to 9, wherein
the acoustic waves with which said measurable object is irradiated are in the form of acoustic wave pulses,
said measurable object is irradiated with said acoustic wave pulses so that a time period for said acoustic wave pulses to propagate over a distance between an emission source of said acoustic wave pulses and said measurable object is longer than a pulse duration of said acoustic wave pulses, and
said electromagnetic waves generated from said measurable object are received by separating in time signals of said electromagnetic waves generated from said measurable obj ect from electromagnetic noises generated by the emission source of said acoustic wave pulses.
[claim11]
11. A method according to any one of claims 7 to 10, wherein
said measurable object (23) is irradiated with acoustic waves by focusing acoustic waves from a plurality of sources of the acoustic waves on a desired small part of the object (23), and
electromagnetic waves induced at said small part are measured with an antenna or coil (28) disposed to surround said object (23) whereby acoustic waves are focused on a desired part and on the desired part from a desired direction and electromagnetic waves radiated from a desired position and from the desired positions towards a desired direction is measured while their radiation bearing distribution is determined.
  • Applicant
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
  • Inventor
  • IKUSHIMA KENJI
  • KOMIYAMA SUSUMU
IPC(International Patent Classification)
Specified countries Contracting States: DE
Reference ( R and D project ) SORST Selected in Fiscal 2001
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