Frequency detection system comprising circuitry for adjusting the resonance frequency of a high temperature superconductor self-resonant coil

• US 20060012371A1
• Filed: 11/22/2004
• Published: 01/19/2006
• Est. Priority Date: 11/24/2003
• Status: Active Grant

• Current Assignee: Penn State Research Foundation (Pennsylvania State University)
• Original Assignee: Penn State Research Foundation (Pennsylvania State University)
• Inventors: Wilker, Charles, Laubacher, Daniel B.
• Granted Patent: US 7,332,910 B2
• Time in Patent Office: Days
• US Class Current: 324/322
• CPC Class Codes: G01N 24/084 Detection of potentially hazardous samples, e.g. toxic samples, explosives, drugs, firearms, weapons
• CPC Class Codes: G01R 33/035 using superconductive devices
• CPC Class Codes: G01R 33/34023 Superconducting RF coils
• CPC Class Codes: G01R 33/3628 Tuning/matching of the transmit/receive coil
• CPC Class Codes: G01R 33/441 Nuclear Quadrupole Resonance [NQR] Spectroscopy and Imaging

Abstract

The use of a circuit to adjust the resonance frequency of a high temperature superconductor self-resonant transmit, receive, or transmit and receive coil results in improved performance. The circuit is useful in a frequency detection system, especially in a nuclear quadrupole resonance detection system.

Claims

1. A circuit to adjust the resonance frequency of a high temperature superconductor self-resonant coil, wherein the circuit is comprised of a single loop or coil to inductively couple the circuit to the high temperature superconductor self-resonant coil, a reactance in series with the single loop or coil, and means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil.

2. The circuit of claim 1 wherein the circuit is comprised of a single loop, and the high temperature superconductor self-resonant coil is a planar coil.

3. The circuit of claim 1 wherein the circuit is comprised of a single loop, and the high temperature superconductor self-resonant coil is comprised of two coupled high temperature superconductor planar coils.

4. The circuit of any of claims 1-3 wherein the reactance can be varied.

5. The circuit of claim 4 wherein the reactance is comprised of two or more capacitors in parallel, and the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil enables each of the capacitors to be individually connected to, and disconnected from, the single loop or coil.

6. The circuit of claim 5 wherein the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil comprises one mechanical or electrical switch for each of the capacitors.

7. The circuit of claim 4 wherein the reactance is comprised of two or more inductors in series, and the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil enables each of the inductors to be individually connected to, and disconnected from, the single loop or coil.

8. The circuit of claim 7 wherein the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil comprises one mechanical or electrical switch for each of the inductors.

9. A frequency detection system, comprising a high temperature superconductor self-resonant transmit and receive coil, and a circuit to adjust the resonance frequency of the high temperature superconductor self-resonant transmit and receive coil;

wherein the circuit is comprised of a single loop or coil to inductively couple the circuit to the high temperature superconductor self-resonant transmit and receive coil, a reactance in series with the single loop or coil, and means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil.

10. The frequency detection system of claim 9 wherein the circuit is comprised of a single loop, and the high temperature superconductor self-resonant transmit and receive coil is a planar coil.

11. The frequency detection system of claim 9 wherein the circuit is comprised of a single loop, and the high temperature superconductor self-resonant transmit and receive coil is comprised of two coupled high temperature superconductor planar coils.

12. The frequency detection system of claim 9 wherein the circuit adjusts the power dependent resonance frequency of the high temperature superconductor self-resonant transmit and receive coil.

13. The frequency detection system of any of claims 9-12 wherein the reactance can be varied.

14. The frequency detection system of claim 13 wherein the reactance is comprised of two or more capacitors in parallel, and the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil enables each of the capacitors to be individually connected to, and disconnected from, the single loop or coil.

15. The frequency detection system of claim 14 wherein the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil comprises one mechanical or electrical switch for each of the capacitors.

16. The frequency detection system of claim 13 wherein the reactance is comprised of two or more inductors in series, and the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil enables each of the inductors to be individually connected to, and disconnected from, the single loop or coil.

17. The frequency detection system of claim 16 wherein the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil comprises one mechanical or electrical switch for each of the inductors.

18. The frequency detection system of any of claims 9-12 which comprises a nuclear quadrupole resonance detection system.

19. The frequency detection system of claim 18 wherein the nuclear quadrupole resonance detection system detects explosives, drugs or other contraband.

20. A frequency detection system, comprising a high temperature superconductor self-resonant transmit coil, and a circuit to adjust the resonance frequency of the high temperature superconductor self-resonant transmit coil;

wherein the circuit is comprised of a single loop or coil to inductively couple the circuit to the high temperature superconductor self-resonant transmit coil, a reactance in series with the single loop or coil, and means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil.

21. The frequency detection system of claim 20 wherein the single loop or coil is a single loop, and the high temperature superconductor self-resonant transmit coil is a planar coil.

22. The frequency detection system of claim 20 wherein the single loop or coil is a single loop, and the high temperature superconductor self-resonant transmit coil is comprised of two coupled high temperature superconductor planar coils.

23. The frequency detection system of claim 20 wherein the circuit adjusts the power dependent resonance frequency of the high temperature superconductor self-resonant coil.

24. The frequency detection system of any of claims 20-23 wherein the reactance can be varied.

25. The frequency detection system of claim 24 wherein the reactance is comprised of two or more capacitors in parallel, and the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil enables each of the capacitors to be individually connected to, and disconnected from, the single loop or coil.

26. The frequency detection system of claim 25 wherein the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil comprises one mechanical or electrical switch for each of the capacitors.

27. The frequency detection system of claim 24 wherein the reactance is comprised of two or more inductors in series, and the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil enables each of the two or more inductors to be individually connected to, and disconnected from, the single loop or coil.

28. The frequency detection system of claim 27 wherein the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil comprises one mechanical or electrical switch for each of the inductors.

29. The frequency detection system of any of claims 20-23 which comprises a nuclear quadrupole resonance detection system.

30. The frequency detection system of claim 29 wherein the nuclear quadrupole resonance detection system detects explosives, drugs or other contraband.

31. A frequency detection system, comprising a high temperature superconductor self-resonant receive coil, and a circuit to adjust the resonance frequency of the high temperature superconductor self-resonant receive coil;

wherein the circuit is comprised of a single loop or coil to inductively couple the circuit to the high temperature superconductor self-resonant transmit and receive coil, a reactance in series with the single loop or coil, and means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil.

32. The frequency detection system of claim 31 wherein the single loop or coil is a single loop, and the high temperature superconductor self-resonant receive coil is a planar coil.

33. The frequency detection system of claim 31 wherein the single loop or coil is a single loop, and the high temperature superconductor self-resonant receive coil is comprised of two coupled high temperature superconductor planar coils.

34. The frequency detection system of any of claims 31-33 wherein the reactance can be varied.

35. The frequency detection system of claim 34 wherein the reactance is comprised of two or more capacitors in parallel, and the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil enables each of the capacitors to be individually connected to, and disconnected from, the single loop or coil.

36. The frequency detection system of claim 35 wherein the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil comprises one mechanical or electrical switch for each of the capacitor.

37. The frequency detection system of claim 34 wherein the reactance is comprised of two or more inductors in series, and the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil enables each of the inductors to be individually connected to, and disconnected from, the single loop or coil.

38. The frequency detection system of claim 37 wherein the means for connecting the reactance to, and disconnecting the reactance from, the single loop or coil comprises one mechanical or electrical switch for each of the inductors.

39. The frequency detection system of any of claims 31-33 which comprises a nuclear quadrupole resonance detection system.

40. The frequency detection system of claim 39 wherein the nuclear quadrupole resonance detection system detects explosives, drugs or other contraband.