SYSTEM AND METHOD FOR ELECTRON SPIN RESONANCE

• US 20130093424A1
• Filed: 10/18/2011
• Published: 04/18/2013
• Est. Priority Date: 10/18/2011
• Status: Active Grant

• Current Assignee: TECHNION RESEARCH AND DEVELOPMENT FOUNDATION, LTD. (Technion-Israel Institute Of Technology)
• Original Assignee: Aharon Blank, Ygal Twig
• Inventors: BLANK, Aharon, TWIG, Ygal
• Granted Patent: US 9,194,922 B2
• Time in Patent Office: Days
• US Class Current: 324/316
• CPC Class Codes: G01R 33/34007 Manufacture of RF coils, e.g. using printed circuit board technology; additional hardware for providing mechanical support to the RF coil assembly or to part thereof, e.g. a support for moving the coil assembly relative to the remainder of the MR system
• CPC Class Codes: G01R 33/341 comprising surface coils
• CPC Class Codes: G01R 33/60 using electron paramagnetic resonance G01R33/24, G01R33/62 take precedence

Abstract

A resonator system for electron spin resonance (ESR) is disclosed. The resonator system comprises: a generally planar resonator layer defining an open-loop gapped by a non-conductive gap in the layer, and a microwave feed, positioned configured for transmitting microwave to the resonator layer such as to concentrate, with a quality factor of at least 100, a magnetic field within an effective volume of less than 1 nL above the layer.

Claims

1. A resonator system for electron spin resonance (ESR), comprising:

a generally planar resonator layer having a thickness of less than 1 micron deposited on a dielectric substrate, said resonator layer defining an open-loop gapped by a non-conductive gap in said layer; and

a microwave feed, positioned opposite to said resonator layer relative to said substrate and configured for transmitting microwave to said resonator layer to concentrate a microwave magnetic field within an effective volume above said layer.

2. The system of claim 1, wherein said effective volume is less than 1 mL and the system is characterized by a quality factor of at least 10.

3. The system of claim 1, further comprising a distance adjusting unit configured for adjusting a distance between said microwave feed and said resonator layer.

4. The system of claim 1, wherein said gap has an elongated shape defining a longitudinal axis generally parallel to said layer.

5. The system of claim 4, wherein said substrate has an anisotropic crystal structure and wherein a c-axis of said crystal structure is generally parallel to said layer and generally perpendicular to said longitudinal axis.

6. The system of claim 4, wherein said substrate has an anisotropic crystal structure and wherein a c-axis of said crystal structure is generally parallel to said layer and generally parallel to said longitudinal axis.

7. The system of claim 1, wherein said resonator layer has a shape of a disc and wherein said gap is extending along a radial direction of said disc.

8. The system of claim 7, wherein said gap comprises a generally round portion at a center of said disc.

9. The system of claim 1, wherein said resonator layer has an elongated shape defining a longitudinal axis and wherein said gap is extending along said longitudinal axis.

10. The system of claim 9, wherein said elongated shape and said gap generally define a U shape.

11. The system of claim 1, wherein said gap widens towards a periphery of said resonator layer.

12. The system of claim 4, wherein said gap has a generally fixed width along said longitudinal axis.

13. The system of claim 1, wherein said gap comprises a fixed width part and a widening part.

14. The system of claim 13, wherein said widening part is an extension of said fixed width.

15. The system of claim 4, wherein said microwave feed comprises an elongated antenna generally parallel to said longitudinal axis.

16. The system of claim 15, wherein said antenna is generally planar.

17. The system of claim 16, wherein said antenna has at least one gap near an end of said antenna and generally perpendicular to said longitudinal axis.

18. The system of claim 17, wherein said at least one gap of said antenna forms an interdigitated pattern.

19. The system of claim 1, being characterized by spin sensitivity of less than 2×

10⁷ spins/√

Hz in a LiPc sample for 1 second of acquisition at a frequency of about 15 GHz and room temperature.

20. The system of claim 1, being characterized by spin sensitivity of less than 2×

10⁸ spins/√

Hz in a SiO₂ sample for 1 second of acquisition at a frequency of about 15 GHz and room temperature.

21. The system of claim 1, being characterized by spin sensitivity of less than 2×

10⁶ spins/√

Hz in a sample of phosphorus doped ²⁸Si for 1 second of acquisition at a frequency of about 14 GHz and temperature about 10K.

22. An ESR system, comprising;

a resonator system according to claim 1;

a controller for activating said resonator system to induce ESR signals within a sample and to receive said signal; and

a data processor configured for receiving from said controller an input indicative of said ESR signals, and providing ESR analysis responsively to said signals.

23. The system of claim 22, further comprising at least one gradient coil configured for spatially encoding said ESR signals from the sample.

24. The system of claim 23, wherein said data processor is configured for generating an image of said sample based on said ESR signals.

25. A method of inducing an electron spin resonance (ESR) signal, comprising:

using a microwave feed for transmitting microwave to a generally planar resonator layer having a thickness of less than 1 micron and defining an open-loop gapped by a non-conductive gap in said layer, such as to concentrate, with a quality factor of at least 100, a magnetic field within an effective volume of less than 1 mL in a sample above said layer.

26. The method of claim 25, further comprising receiving said signal using said resonator layer, and performing ESR analysis responsively to said signal.

27. The method of claim 26, wherein said ESR analysis comprises imaging.

28. The method of claim 26, wherein said sample is selected from the group consisting of a surface or sub-surface of a semiconductor structure, a paramagnetic monolayer, a biological sample, and a spin-limited sample.

29. The method of claim 26, further comprising varying a distance between said microwave feed and said resonator layer.

30. A resonator system for electron spin resonance (ESR), comprising a generally planar resonator layer and a microwave feed configured for transmitting microwave to said resonator layer, such as to concentrate, with a quality factor of at least 10, a magnetic field within an effective volume of less than 1 mL above said layer.