Probe head for nuclear magnetic resonance measurements

• US 6,278,277 B1
• Filed: 07/19/1999
• Issued: 08/21/2001
• Est. Priority Date: 07/24/1998
• Status: Expired due to Term

• Current Assignee: Bruker Analytik GmbH
• Original Assignee: Bruker Analytik GmbH
• Inventors: Zeiger, Heinz
• Primary Examiner(s): Oda, Christine
• Assistant Examiner(s): Shrivastav, Brij B.
• Application Number:
  US09/357,524
• Time in Patent Office: 764 Days
• Field of Search: 324/322, 324/318, 324/300
• US Class Current: 324/322
• CPC Class Codes: G01R 33/34 Constructional details, e.g. resonators , specially adapted to MR
• CPC Class Codes: G01R 33/34053 Solenoid coils; Toroidal coils
• CPC Class Codes: G01R 33/34092 RF coils specially adapted for NMR spectrometers
• CPC Class Codes: G01R 33/3635 Multi-frequency operation

Abstract

A probe head is used for nuclear resonance measurements during which two different kinds of nuclei are excited by means of radio frequency irradiation in a constant magnetic field. The probe head is provided with a pick-up coil receiving a sample under investigation. The pick-up coil is connected to a first input for feeding a signal of higher frequency for exciting a first kind of nuclei and/or for receiving a resonance signal emitted by the first kind of nuclei. The pick-up coil, further, is connected to a second input for feeding a signal of a lower frequency for exciting a second kind of nuclei and/or for receiving a resonance signal emitted by the second kind of nuclei. The pick-up coil, moreover, is connected to a radio frequency line the electrical length of which corresponds to an integer multiple of a quarter of the wave length of the higher frequency. A series capacitor is interconnected between the radio frequency line and the pick-up coil.

Claims

1. A probe head for nuclear magnetic resonance measurements, wherein at least two different kinds of nuclei are excited by means of radio frequency irradiation within a constant magnetic field, the probe head comprising:

a pick-up coil cooperating with a sample,

said pick-up coil being connected to a first input for feeding a signal of a higher radio frequency to said pick-up coil for exciting a first kind of nuclei and/or for receiving from said pick-up coil a resonance signal emitted by said nuclei of said first kind of nuclei,

said coil being, further, connected to a second input for feeding a signal of a lower radio frequency to said pick-up coil for exciting a second kind of nuclei and/or for receiving from said pick-up coil a resonance signal emitted by said nuclei of said second kind of nuclei,

a radio frequency line being also connected to said pick-up coil, said radio frequency line having an electrical length corresponding to an integer multiple of a quarter wave length of said higher radio frequency; and

a series capacitor being interconnected between said radio frequency line and said pick-up coil.

2. The probe head of claim 1, wherein said radio frequency line is a λ

/4 line.

3. The probe head of claim 1, wherein said series capacitor is adapted to be bridged.

4. The probe head of claim 1, wherein said constant magnetic field has a field strength in excess of 9 Tesla.

5. The probe head of claim 1, wherein said constant magnetic field has a direction and said sample is rotated under an angle of 54°

44′

relative to said direction.

6. A probe head for nuclear magnetic resonance measurements, wherein at least two different kinds of nuclei are excited by means of radio frequency irradiation within a constant magnetic field, the probe head comprising;

a pick-up coil cooperating with a sample,

said pick-up coil being connected to a first input for receiving a signal of a first radio frequency and operative to excite a first kind of nuclei, and/or for receiving a resonance signal emitted by said nuclei of said first kind of nuclei,

said pick-up coil being further connected to a second input for receiving a signal of a second radio frequency lower than said first radio frequency and operative to excite a second kind of nuclei, and/or for receiving a resonance signal emitted by said nuclei of said second kind of nuclei,

a radio frequency line connected to said pick-up coil, said radio frequency line having an electrical length corresponding to an integer multiple of a quarter wave length of said first radio frequency; and

a series capacitor interconnected between said radio frequency line and said pick-up coil, said series capacitor being dimensioned such that a radio frequency voltage of said second radio frequency has opposite polarity at terminal ends of said pick-up coil.

7. The probe head of claim 6, wherein said radio frequency line is a λ

/4 line.

8. The probe head of claim 6, wherein said series capacitor is adapted to be bridged.

9. The probe head of claim 6, wherein said probe head and said sample are adapted to be positioned within a constant magnetic field having a field strength in excess of 9 Tesla.

10. The probe head of claim 6, wherein said probe head and said sample are adapted to be positioned within a constant magnetic field having a predetermined direction, and wherein said sample is rotated under an angle of 54°

44′

relative to said direction.

11. A probe head for nuclear magnetic resonance measurements, wherein at least two different kinds of nuclei are excited by means of radio frequency irradiation within a constant magnetic field, the probe head comprising:

a pick-up coil cooperating with a sample,

said pick-up coil being connected to a first input for receiving a signal of a first radio frequency and operative to excite a first kind of nuclei, and/or for receiving a resonance signal emitted by said nuclei of said first kind of nuclei, wherein said first kind of nuclei is protons (¹H), and having a first resonance frequency proportional to a predetermined magnetic field strength, wherein at a constant magnetic field of 13.8 Tesla field strength, said first resonance frequency is about 800 MHz,

said pick-up coil being further connected to a second input for receiving a signal of a second radio frequency lower than said first radio frequency and operative to excite a second kind of nuclei, and/or for receiving a resonance signal emitted by said nuclei of said second kind of nuclei, wherein said second kind of nuclei is phosphor (³¹P) and has a second resonance frequency proportional to said predetermined magnetic field strength, and wherein said second resonance frequency is about 324 MHz,

a radio frequency line connected to said pick-up coil, said radio frequency line having an electrical length corresponding to an integer multiple of a quarter wave length of said first radio frequency; and

a series capacitor interconnected between said radio frequency line and said pick-up coil.

12. The probe head of claim 11, wherein said series capacitor is dimensioned such that a radio frequency voltage of said second radio frequency has opposite polarity at terminal ends of said pick-up coil.

13. The probe head of claim 11 wherein said radio frequency line is a λ

/4 line.

14. The probe head of claim 11, wherein said series capacitor is adapted to be bridged.

15. The probe head of claim 11, wherein said probe head and said sample are adapted to be positional within a constant magnetic field having a predetermined direction, and wherein said sample is rotated under an angle of 54°

44′

relative to said direction.

16. A probe head for nuclear magnetic resonance measurements, wherein at least two different kinds of nuclei are excited by means of radio frequency irradiation within a constant magnetic field, the probe head comprising:

a pick-up coil cooperating with a sample,

a first input for feeding a signal of a first radio frequency to said pick-up coil for exciting a first kind of nuclei, and/or for receiving from said pick-up coil a resonance signal emitted by said nuclei of said first kind of nuclei, wherein said first kind of nuclei is phosphor (³¹P) and has a first resonance frequency proportional to a predetermined magnetic field strength, wherein at a constant magnetic field of 11.8 Tesla field strength, said first resonance frequency is about 202 MHz,

a second input for feeding a signal of a second radio frequency to said pick-up coil for exciting a second kind of nuclei, and/or for receiving from said pick-up coil a resonance signal emitted by said nuclei of said second kind of nuclei wherein said second kind of nuclei is silicon (²⁹Si) and has a second resonance frequency proportional to said predetermined magnetic field strength, and

wherein said second resonance frequency is about 99 MHz,

a radio frequency line also connected to said pick-up coil, said radio frequency line having an electrical length corresponding to an integer multiple of a quarter wave length of said first radio frequency; and

a series capacitor interconnected between said radio frequency line and said pick-up coil.

17. The probe head of claim 16, wherein said series capacitor is dimensioned such that a radio frequency voltage of said second radio frequency has opposite polarity at terminal ends of said pick-up coil.

18. The probe head of claim 16, wherein said radio frequency line is a λ

/4 line.

19. The probe head of claim 16, wherein said series capacitor is adapted to be bridged.

20. The probe head of claim 16, wherein said constant magnetic field has a predetermined direction and said sample is rotated within said field under an angle of 54°

44′

relative to said direction.

21. The probe head of claim 16, wherein said series capacitor is dimensioned such that a radio frequency voltage of said second radio frequency has opposite polarity at terminal ends of said pick-up coil.

22. A probe head for nuclear magnetic resonance measurements, wherein at least two different kinds of nuclei are excited by means of radio frequency irradiation within a constant magnetic field, the probe head comprising:

a pick-up coil cooperating with a sample,

said pick-up coil being connected to a first input used for feeding a signal of a first radio frequency to said pick-up coil for exciting a first kind of nuclei, and/or for receiving from said pick-up coil a resonance signal emitted by said nuclei of said first kind of nuclei, wherein said first kind of nuclei is phosphor (³¹P) and has a first resonance frequency proportional to a predetermined magnetic field strength, and wherein at a constant magnetic field of 11.8 Tesla field strength, said first resonance frequency is about 202 MHz,

said pick-up coil being further connected to a second input used for feeding a signal of a second radio frequency lower than said first radio frequency to said pick-up coil for exciting a second kind of nuclei, and/or for receiving from said pick-up coil a resonance signal emitted by said nuclei of said second kind of nuclei, wherein said second kind of nuclei is aluminum (²⁷Al) and has a second resonance frequency proportional to said predetermined magnetic field strength, and wherein said second resonance frequency is about 122 MHz,

a radio frequency line also connected to said pick-up coil, said radio frequency line having an electrical length corresponding to an integer multiple of a quarter wave length of said higher radio frequency; and

a series capacitor interconnected between said radio frequency line and said pick-up coil.

23. The probe head of claim 22, wherein said radio frequency line is a λ

/4 line.

24. The probe head of claim 22, wherein said series capacitor is adapted to be bridged.

25. The probe head of claim 22, wherein said constant magnetic field has a predetermined direction and said sample is rotated within said field under an angle of 54°

44′

relative to said direction.

26. A probe head for nuclear magnetic resonance measurements, wherein at least two different kinds of nuclei are excited by means of radio frequency irradiation within a constant magnetic field, the probe head comprising:

a pick-up coil cooperating with a sample, said constant magnetic field having a predetermined direction and said sample being rotated within said field under an angle of 54°

44′

relative to said direction,

said pick-up coil being connected to a first input used for feeding a signal of a first radio frequency to said pick-up coil for exciting a first kind of nuclei, and/or for receiving from said pick-up coil a resonance signal emitted by said nuclei of said first kind of nuclei,

said coil being further connected to a second input used for feeding a signal of a second radio frequency lower than said first radio frequency to said pick-up coil for exciting a second kind of nuclei, and/or for receiving from said pick-up coil a resonance signal emitted by said nuclei of said second kind of nuclei,

a radio frequency line connected to said pick-up coil, said radio frequency line having an electrical length corresponding to an integer multiple of a quarter wave length of said first radio frequency; and

a series capacitor interconnected between said radio frequency line and said pick-up coil.