Integrated EPR NMR with frequency agile gyrotron

Patent metadata

Field	Value
Publication number	US-10113984-B2
Application number	US-201515310509-A
Country	US
Kind code	B2
Filing date	May 12, 2015
Priority date	May 15, 2014
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

A frequency agile gyrotron for use in combination with an NMR system is disclosed. The frequency agile gyrotron combined with EPR-NMR magic angle spinning resonators and cryogenic sample cooling may increase the sensitivity of solid state NMR with DNP.

First claim

What is claimed is:

1. A frequency agile gyrotron system for DNP (dynamic nuclear polarization) NMR (nuclear magnetic resonance) comprising:
an NMR spectrometer;
a signal processor operatively connected to the NMR spectrometer, wherein the signal processor receives one or more voltages from the NMR spectrometer and produces a control signal; and
a frequency agile gyrotron operatively coupled to the NMR spectrometer and to the signal processor, the frequency agile gyrotron configured to emit a broad-banded microwave output comprising a gyrotron bandwidth;
wherein:
the NMR spectrometer controls a frequency of the broad-banded microwave output via the control signal,
the frequency agile gyrotron responds to the control signal on a timescale of microseconds, and
the gyrotron bandwidth is wider than an EPR (polarization of electron spins) linewidth and a NMR frequency.

2. The system of claim 1 , wherein the gyrotron bandwidth of the frequency agile gyrotron is between 10 MHz and 1000 MHz.

3. The system of claim 1 , wherein:
the NMR spectrometer further comprises a magnetron injection gun comprising a cathode and an anode; and
the one or more voltages from the NMR spectrometer are chosen from at least one of: a cathode voltage, an anode voltage, and an acceleration voltage comprising a voltage difference between the cathode voltage and the anode voltage.

4. The system of claim 1 , wherein the frequency agile gyrotron is operated as a backward wave oscillator.

5. The system of claim 1 , wherein the frequency agile gyrotron produces the broad-banded microwave output at a phase and frequency stable condition.

6. The system of claim 5 , wherein the broad-banded microwave output is sliced or gated to provide at least one of: a wide instantaneous bandwidth comprising short pulses on a nanosecond scale and an adjustable power transmission length for phase control.

7. The system of claim 1 , wherein the NMR spectrometer further comprises a combined EPR-NMR magic angle spinning resonator.

8. The system of claim 1 , further comprising a helium cooling system for cooling a sample to below 5 to about 60 Kelvin with helium using a spinning MAS (magic angle spinning) rotor as a centrifugal gas compressor.

9. A method of DNP (dynamic nuclear polarization) NMR (nuclear magnetic resonance) using a frequency agile gyrotron system comprising a NMR spectrometer operatively coupled to a frequency agile gyrotron, the method comprising controlling an output frequency of a broad-banded microwave output produced by the frequency agile gyrotron by changing an operational voltage of the frequency agile gyrotron in response to a control signal corresponding to at least one voltage received from a magnetron injection gun of the NMR spectrometer, the at least one voltage chosen from: a cathode voltage, an anode voltage, and an acceleration voltage comprising a voltage difference between the cathode voltage and the anode voltage.

10. The method of claim 9 , wherein controlling the output frequency of the broad-banded microwave output produced by the frequency agile gyrotron comprises at least one of:
sweeping the output frequency on a timescale ranging from nanoseconds to microseconds;
producing the broad-banded microwave output in short pulses; and
producing the broad-banded microwave output in a phase and frequency stable form and gating the broad-banded microwave output with at least one nanosecond scale switches.

11. The method of claim 9 , further comprising at least one of:
performing at least one time-domain DNP transfer;
transferring polarization from electrons to a nucleus using hyperfine couplings of greater than 10 KHz;
decoupling an electron spin from a nuclear spin; and
manipulating EPR (polarization of electron spins) spins during magic angle spinning NMR and EPR experiments to measure EPR to NMR distances and orientations.

12. The method of claim 11 , wherein the operational voltage of the frequency agile gyrotron is changed on a timescale ranging from nanoseconds to microseconds to perform the at least one time-domain DNP transfer.

13. The method of claim 12 , wherein the at least one time-domain DNP transfer is accomplished using at least one transfer mechanism chosen from: integrated solid effect, a nuclear orientation via electron spin locking, and an electron nuclear cross polarization.

14. The method of claim 9 , further comprising cooling a sample to below 5 to 60 Kelvin with helium using a spinning MAS (magic angle spinning) rotor as a centrifugal gas compressor.

Assignees

• Univ Washington

Inventors

• Barnes Alexander B

Classifications

• G01R33/62

  using double resonance (G01R33/24 takes precedence) · CPC title

• G01R33/307

  specially adapted for moving the sample relative to the MR system, e.g. spinning mechanisms, flow cells or means for positioning the sample inside a spectrometer · CPC title

• G01R33/282

  Means specially adapted for hyperpolarisation or for hyperpolarised contrast agents, e.g. for the generation of hyperpolarised gases using optical pumping cells, for storing hyperpolarised contrast agents or for the determination of the polarisation of a hyperpolarised contrast agent · CPC title

• G01R33/31

  Temperature control thereof · CPC title

• G01R33/345

  of waveguide type (G01R33/343 takes precedence) · CPC title