Tunnel effect measuring systems and particle detectors

• US 5,265,470 A
• Filed: 04/15/1991
• Issued: 11/30/1993
• Est. Priority Date: 11/09/1987
• Status: Expired due to Term

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Kaiser, William J., Kenny, Thomas W., Waltman, Steven B.
• Primary Examiner(s): WOODIEL, DONALD
• Application Number:
  US07/685,553
• Time in Patent Office: 960 Days
• Field of Search: 73/178 R, 73/178 H, 73/178 T, 73/763, 73/862.621, 73/862.625, 73/862.636, 73/862.637, 73/862.639, 33/391, 33/398, 33/300, 357/26
• US Class Current: 73/178.00R
• CPC Class Codes: G01P 15/0894 by non-contact electron transfer, i.e. electron tunneling
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/131 with electrostatic counterbalancing means
• CPC Class Codes: G01P 15/132 with electromagnetic counterbalancing means
• CPC Class Codes: G01P 15/133 with piezoelectric counterbalancing means
• CPC Class Codes: G01P 2015/0828 the mass being of the paddle type being suspended at one of its longitudinal ends
• CPC Class Codes: Y10S 977/852 for detection of specific nanostructure sample or nanostructure-related property

Abstract

Methods and apparatus for measuring gravitational and inertial forces, magnetic fields, or wave or radiant energy acting on an object or fluid in space provide an electric tunneling current through a gap between an electrode and that object or fluid in space and vary that gap with any selected one of such forces, magnetic fields, or wave or radiant energy acting on that object or fluid. These methods and apparatus sense a corresponding variation in an electric property of that gap and determine the latter force, magnetic fields, or wave or radiant energy in response to that corresponding variation, and thereby sense or measure such parameters as acceleration, position, particle mass, velocity, magnetic field strength, presence or direction, or wave or radiant energy intensity, presence or direction.

Claims

1. A method of determining a position of an object in space, comprising in combination the steps of:

providing an electric tunneling current through a tunneling gap between an electrode and said object in space;

determining a position of said object in space when providing said electric tunneling current through a tunneling gap between an electrode and said object in space;

varying said gap with a force acting on said object by changing said object in position to induce a corresponding variation in an electrical property of said gap relating to said tunneling current; and

determining the direction of said force relative to said object from said corresponding variation in said electrical property and thereby the changed position of said object in space.

2. A method as in claim 1, including in combination the steps of:

providing a constant current source; and

deriving said electric tunneling current from said constant current source.

3. A method as claimed in claim 2, including the steps of:

determining said first position by observing a voltage provided by said source upon flow of current when said gap has a quiescent value;

deriving a determination of said changed position from a change in that voltage; and

restoring said gap to its quiescent value in response to that change in voltage.

4. A method as claimed in claim 2, including the steps of:

providing a servo loop responding to a change in voltage caused by current from said source in response to each variation of said gap;

restoring said gap with said servo loop in response to said change in voltage; and

providing a servo loop output signal indicative of changes in position varying said gap.

5. A method as claimed in claim 2, including the step of:

elastically suspending said object.

6. A method as claimed in claim 2, including the steps of:

elastically suspending said object; and

restoring said elastically suspended object in position in response to said variation in said electrical property.

7. A method as claimed in claim 2, wherein:

said object is integral with an elastic beam restorable in position by a feedback signal upon deflection of said elastic beam;

said elastic beam is deflected when changing said object in position to provide said variation in said electrical property;

a feedback signal is derived from said variation in said electrical property;

said deflected beam is restored in position with said derived feedback signal; and

an output signal indicative of said change of said object in position is provided.

8. A method as claimed in claim 2, including the steps of:

integrating said object with an elastic beam;

making said elastic beam deflectable by a feedback signal;

deflecting said elastic beam when changing said object in position to provide said variation in said electrical property;

providing a servo loop responding to a change in voltage caused by current from said source in response to the latter variation in said electrical property;

deriving said feedback signal with said servo loop from said change in voltage;

restoring said deflected beam in position with said derived feedback signal; and

providing a servo loop output signal indicative of said change in position.

9. A method as claimed in claim 2, wherein:

said force is a gravitational force.

10. A method as claimed in claim 2, wherein:

said force is an inertial force.

11. A method as claimed in claim 2, wherein:

said force is provided by impacting particles on said object.

12. A method as claimed in claim 2, wherein:

said force is provided by impacting wave energy on said object.

13. A method as claimed in claim 12, wherein:

said wave energy is radiant energy.

14. A method as claimed in claim 2, wherein:

said force is provided by impacting acoustic energy on said object.

15. A method as claimed in claim 2, wherein:

said force is a magnetic force.

16. A method as in claim 1, including in combination the steps of:

providing a constant voltage source; and

deriving said electric tunneling current from said constant voltage source.

17. A method as claimed in claim 16, including the steps of:

determining said first position by observing a voltage upon flow of current from said source when said gap has a quiescent value;

deriving a determination of said changed position from a change in that voltage; and

restoring said gap to its quiescent value in response to that change in voltage.

18. A method as claimed in claim 16, including the steps of:

providing a servo loop responding to a change in voltage caused by current from said source in response to each variation of said gap;

restoring said gap with said servo loop in response to said change in voltage; and

providing a servo loop output signal indicative of changes in position varying said gap.

19. A method as claimed in claim 16, including the step of:

elastically suspending said object.

20. A method as claimed in claim 16, including the steps of:

elastically suspending said object; and

restoring said elastically suspended object in position in response to said variation in said electrical property.

21. A method as claimed in claim 16, wherein:

said object is integral with an elastic beam restorable in position by a feedback signal upon deflection of said elastic beam;

said elastic beam is deflected when changing said object in position to provide said variation in said electrical property;

a feedback signal is derived from said variation in said electrical property;

said deflected beam is restored in position with said derived feedback signal; and

an output signal indicative of said change of said object in position is provided.

22. A method as claimed in claim 16, including the steps of:

integrating said object with an elastic beam;

making said elastic beam deflectable by a feedback signal;

deflecting said elastic beam when changing said object in position to provide said variation in said electrical property;

providing a servo loop responding to a change in voltage caused by current from said source in response to the latter variation in said electrical property;

deriving said feedback signal with said servo loop from said change in voltage;

restoring said deflected beam in position with said derived feedback signal; and

providing a servo loop output signal indicative of said change in position.

23. A method as claimed in claim 16, wherein:

said force is a gravitational force.

24. A method as claimed in claim 16, wherein:

said force is an inertial force.

25. A method as claimed in claim 16, wherein:

said force is provided by impacting particles on said object.

26. A method as claimed in claim 16, wherein:

said force is provided by impacting wave energy on said object.

27. A method as claimed in claim 26, wherein:

said wave energy is radiant energy.

28. A method as claimed in claim 16, wherein:

said force is provided by impacting acoustic energy on said object.

29. A method as claimed in claim 16, wherein:

said force is a magnetic force.

44. A method as claimed in claim 1, wherein:

said force is a gravitational force.

45. A method as claimed in claim 1, wherein:

said force is an inertial force.

46. A method as claimed in claim 1, wherein:

said force is provided by impacting particles on said object.

47. A method as claimed in claim 1, wherein:

said force is provided by impacting wave energy on said object.

48. A method as claimed in claim 47, wherein:

said wave energy is radiant energy.

49. A method as claimed in claim 1, wherein:

said force is provided by impacting acoustic energy on said object.

50. A method as claimed in claim 1, wherein:

said force is a magnetic force.

30. A method of determining a position of an object in space, comprising in combination the steps of:

providing an elastic beam for suspending said object;

making said elastic beam deflectable by an electrostatic feedback signal;

providing a tunneling gap between a tunneling tip and an electrode;

connecting one of said tunneling tip and said electrode to said elastic beam;

providing an electric tunneling current through said tunneling gap between said tunneling tip and said electrode;

determining a position of said object in space when providing said electric tunneling current;

deflecting said elastic beam with a force acting on said object by changing said object in position to provide a corresponding variation in an electrical property of said gap relating to said tunneling current;

providing a servo loop responding to said variation in said electrical property;

deriving said electrostatic feedback signal from the servo loop;

restoring said deflected beam in position with said derived electrostatic feedback signal;

providing a servo loop output signal indicative of said force; and

determining the direction of said force relative to said object from said corresponding variation in said electrical property and thereby the changed position of said object in space.

31. A method as in claim 30, wherein:

said tunneling tip is provided on a second elastic beam.

32. A method as in claim 30, wherein:

said elastic beam is composed of two elastic beam structures having said one of said tunneling tip and said electrode located therebetween.

33. A method as in claim 30, wherein:

said beam is structured as a folded beam.

34. A method as in claim 30, wherein:

said elastic beam is composed of a pair of folded beam structures having said one of said tunneling tip and said electrode located therebetween.

35. A method as claimed in claim 30, including the steps of:

providing a constant current source for said electric tunneling current;

responding with said servo loop to a change in voltage caused by current from said source in response to each variation of said gap; and

effecting restoration of the position of said beam in response to said change in voltage.

36. A method as claimed in claim 30, including the steps of:

providing a constant voltage source for said electric tunneling current;

responding with said servo loop to a change in voltage caused by current from said source in response to each variation of said gap; and

effecting restoration of the position of said beam in response to said change in voltage.

37. A method as claimed in claim 30, wherein:

said force is a gravitational force.

38. A method as claimed in claim 30, wherein:

said force is an inertial force.

39. A method as claimed in claim 30, wherein:

said force is provided by impacting particles on said object.

40. A method as claimed in claim 30, wherein:

said force is provided by impacting wave energy on said object.

41. A method as claimed in claim 40, wherein:

said wave energy is radiant energy.

42. A method as claimed in claim 30, wherein:

said force is provided by impacting acoustic energy on said object.

43. A method as claimed in claim 30, wherein:

said force is a magnetic force.

51. Apparatus for determining a position of an object in space, comprising in combination:

means for providing an electric tunneling current through a tunneling gap between an electrode and said object in space;

means for determining a position of said object in space when providing said electric tunneling current through a tunneling gap between an electrode and said object in space;

means for varying said gap with a force acting on said object by changing said object in position to induce a corresponding variation in an electrical property of said gap relating to said tunneling current; and

means for determining the direction of said force relative to said object from said corresponding variation in said electrical property and thereby the changed position of said object in space.

52. Apparatus as in claim 51, wherein:

said means for providing said electric tunneling current through said tunneling gap include a constant current source.

53. Apparatus as claimed in claim 52, wherein:

said means for determining said first position include means for sensing a voltage provided by said source upon flow of current when said gap has a quiescent value, means for deriving a determination of said changed position from a change in that voltage, and means for restoring said gap to its quiescent value in response to that change in voltage.

54. Apparatus as claimed in claim 52, including:

means including a servo loop responding to a change in voltage caused by current from said source in response to each variation of said gap;

means connected to said servo loop for restoring said gap with said servo loop in response to said change in voltage; and

means connected to said servo loop for providing a servo loop output signal indicative of changes in position varying said gap.

55. Apparatus as claimed in claim 52, wherein:

said object is elastically suspended; and

said apparatus includes means for restoring said elastically suspended object in position in response to said variation in said electrical property.

56. Apparatus as claimed in claim 52, wherein:

said force is a gravitational force.

57. Apparatus as claimed in claim 52, wherein:

said force is an inertial force.

58. Apparatus as claimed in claim 52, including:

means for providing said force by impacting particles on said object.

59. Apparatus as claimed in claim 52, including:

means for providing said force by impacting wave energy on said object.

60. Apparatus as claimed in claim 59, wherein:

said wave energy is radiant energy.

61. Apparatus as claimed in claim 52, including:

means for providing said force by impacting acoustic energy on said object.

62. Apparatus as claimed in claim 52, wherein:

said force is a magnetic force.

63. Apparatus as claimed in claim 51, wherein:

said force is a gravitational force.

64. Apparatus as claimed in claim 51, wherein:

said force is an inertial force.

65. Apparatus as claimed in claim 51, including:

means for providing said force by impacting particles on said object.

66. Apparatus as claimed in claim 51, including:

means for providing said force by impacting wave energy on said object.

67. Apparatus as claimed in claim 66, wherein:

said wave energy is radiant energy.

68. Apparatus as claimed in claim 51, including:

means for providing said force by impacting acoustic energy on said object.

69. Apparatus as claimed in claim 51, wherein:

said force is a magnetic force.

70. Apparatus as in claim 51, wherein:

said means for providing said electric tunneling current through said tunneling gap include a constant voltage source.

71. Apparatus as claimed in claim 70, wherein:

said means for determining said first position include means for sensing a voltage provided by said source upon flow of current when said gap has a quiescent value, means for deriving a determination of said changed position from a change in that voltage, and means for restoring said gap to its quiescent value in response to that change in voltage.

72. Apparatus as claimed in claim 70, including:

means including a servo loop responding to a change in voltage caused by current from said source in response to each variation of said gap;

means connected to said servo loop for restoring said gap with said servo loop in response to said change in voltage; and

means connected to said servo loop for providing a servo loop output signal indicative of changes in position varying said gap.

73. Apparatus as claimed in claim 70, wherein:

means including a servo loop responding to a change in voltage caused by current from said source in response to each variation of said gap;

means connected to said servo loop for restoring said gap with said servo loop in response to said change in voltage; and

means connected to said servo loop for providing a servo loop output signal indicative of changes in position varying said gap.

74. Apparatus as claimed in claim 70, wherein:

said force is a gravitational force.

75. Apparatus as claimed in claim 70, wherein:

said force is an inertial force.

76. Apparatus as claimed in claim 70, including:

means for providing said force by impacting particles on said object.

77. Apparatus as claimed in claim 70, including:

means for providing said force by impacting wave energy on said object.

78. Apparatus as claimed in claim 77, wherein:

said wave energy is radiant energy.

79. Apparatus as claimed in claim 70, including:

means for providing said force by impacting acoustic energy on said object.

80. Apparatus as claimed in claim 70, wherein:

said force is a magnetic force.

81. Apparatus for determining a position of an object in space, comprising in combination:

an elastic beam suspending said object;

means for deflecting said elastic beam with an electrostatic feedback signal;

a tunneling tip, an electrode, and a tunneling gap between said tunneling tip and said electrode, one of said tunneling tip and said electrode connected to said elastic beam;

means for providing an electric tunneling current through said tunneling gap between said tunneling tip and said electrode;

means for determining a position of said object in space when providing said electric tunneling current;

means for deflecting said elastic beam with a force acting on said object by changing said object in position to provide a corresponding variation in an electrical property of said gap relating to said tunneling current;

means including a servo loop responding to said variation in said electrical property;

means for deriving said electrostatic feedback signal from the servo loop;

means connected to said means for deriving said electrostatic feedback signal and to said means for deflecting said elastic beam, for restoring said deflected beam in position with said derived electrostatic feedback signal;

means connected to said servo loop for providing a servo loop output signal indicative of said force; and

means for determining the direction of said force relative to said object from said corresponding variation in said electrical property and thereby the changed position of said object in space.

82. Apparatus as in claim 81, including:

a second elastic beam, said tunneling tip located on said second elastic beam.

83. Apparatus as in claim 81, wherein:

said elastic beam includes two elastic beam structures having said one of said tunneling tip and said electrode located therebetween.

84. Apparatus as in claim 81, wherein:

said beam is a folded beam.

85. Apparatus as in claim 81, wherein:

said elastic beam includes a pair of folded beam structures having said one of said tunneling tip and said electrode located therebetween.

86. Apparatus as claimed in claim 81, including:

a constant current source for said electric tunneling current;

said means including a servo loop include means for responding to a change in voltage caused by current from said source in response to each variation of said gap; and

said means for restoring said deflected beam in position include means for effecting restoration of the position of said beam in response to said change in voltage.

87. Apparatus as claimed in claim 81, including:

a constant voltage source for said electric tunneling current;

a constant current source for said electric tunneling current;

said means including a servo loop include means for responding to a change in voltage caused by current from said source in response to each variation of said gap; and

said means for restoring said deflected beam in position include means for effecting restoration of the position of said beam in response to said change in voltage.

88. Apparatus as claimed in claim 81, wherein:

said force is a gravitational force.

89. Apparatus as claimed in claim 81, wherein:

said force is an inertial force.

90. Apparatus as claimed in claim 81, including:

means for providing said force by impacting particles on said object.

91. Apparatus as claimed in claim 81, including:

means for providing said force by impacting wave energy on said object.

92. Apparatus as claimed in claim 91, wherein:

said wave energy is radiant energy.

93. Apparatus as claimed in claim 81, including:

means for providing said force by impacting acoustic energy on said object.

94. Apparatus as claimed in claim 81, wherein:

said force is a magnetic force.