MAS-NMR rotor system with improved space utilization

Patent metadata

Field	Value
Publication number	US-10830845-B2
Application number	US-201816194907-A
Country	US
Kind code	B2
Filing date	Nov 19, 2018
Priority date	Nov 20, 2017
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

A first radial bearing includes nozzles in the stator at a radius r 1 and a bearing surface on a circular section of the rotor at a radius R 1 . A second radial bearing includes nozzles in the stator at a radius r 2 and a bearing surface on the rotor at a radius R 2 . An axial bearing includes a nozzle in the stator and a bearing surface on an axial end of the rotor, which runs orthogonally to the rotation axis and has an outer radius R 3 . The second radial bearing is formed on an end section of the rotor, which has a smaller radius than or a radius that decreases away from the circular section, so that R 2 <R 1 and r 2 <r 1 . The third bearing surface is formed on an end of the end section facing away from the circular section, so that R 3 ≤R 2.

First claim

What is claimed is:

1. A magic angle spinning (MAS) nuclear magnetic resonance (NMR) rotor system, comprising:
a rotor configured to accommodate a measurement substance,
a stator configured to mount the rotor rotatably about a rotation axis,
a first pneumatic radial bearing, comprising first nozzle outlet openings in the stator at a radius r 1 and a first bearing surface on a circular cylindrically-shaped section of the rotor at a radius R 1 ,
a second pneumatic radial bearing, comprising second nozzle outlet openings in the stator at a radius r 2 and a second bearing surface on the rotor at a radius R 2 , and
a pneumatic axial bearing, comprising at least one nozzle outlet opening in the stator and a third bearing surface on an axial end of the rotor,
wherein the third bearing surface runs orthogonally to the rotation axis and has an outer radius R 3 ,
wherein the second pneumatic radial bearing is formed on an end section of the rotor which, as compared to the circular cylindrically-shaped section, has a smaller radius or a radius that decreases away from the circular cylindrically-shaped section, such that: R 2 <R 1 and r 2 <r 1 , and
wherein the third bearing surface is formed on an end of the end section that faces away from the circular cylindrically-shaped section, such that: R 3 ≤R 2 .

2. The rotor system according to claim 1 , wherein the end section is at least partially circularly cylindrical in shape.

3. The rotor system according to claim 1 , wherein the end section is at least partially truncated conical in shape.

4. The rotor system according to claim 3 , wherein the end section runs at least partially at an angle α relative to the rotation axis, where 15°≤α≤45°.

5. The rotor system according to claim 1 , wherein the stator encompasses the third bearing surface and at least an adjoining portion of the end section in a cup-shaped manner, and wherein air outlet openings are provided in the stator in an area of the third bearing surface and/or of the end section.

6. The rotor system according to claim 5 , wherein the stator encompasses an entirety of the end section.

7. The rotor system according to claim 1 , wherein the end section extends over no more than ¼ of the length of the rotor and/or extends at least over 1/20 of the length of the rotor.

8. The rotor system according to claim 1 , wherein the rotor) includes an opening at an end that faces away from the third bearing surface and is configured for filling the rotor with the measurement substance, and wherein the rotor includes a cap, which seals the opening of the rotor.

9. The rotor system according to claim 8 , wherein counter structures are formed on the cap as a pneumatic drive for the rotor.

10. The rotor system according to claim 9 , wherein the pneumatic drive comprises at least one of: impact surfaces, wing surfaces or spiral grooves.

11. The rotor system according to claim 8 , wherein an outer radius R 4 of the cap corresponds at least substantially to the radius R 1 .

12. The rotor system according to claim 8 , wherein the circular cylindrically-shaped section extends from the end section to the opening.

13. The rotor system according to claim 1 , wherein the rotor is closed in an area of the third bearing surface.

14. The rotor system according to claim 1 , further comprising a counter bearing,
which lies opposite the axial bearing.

15. A probe head assembly, comprising:
a rotor system according to claim 1 ,
a RF coil arrangement configured to irradiate RF pulses into the measurement substance in the rotor and/or to receive RF signals from the measurement substance in the rotor,

wherein the stator includes a first bearing base, comprising a portion of the first radial bearing on the stator, a sheath element and a second bearing base, comprising a portion of the second radial bearing on the stator,
wherein the sheath element connects the first bearing base and the second bearing base to one another,
wherein the sheath element includes a front section, which connects to the second bearing base and has a maximum outer diameter ADV,
wherein the second bearing base has a maximum outer diameter AD 2 ,
wherein the stator has a maximum outer diameter AD 1 in an area of the first radial bearing, and
wherein the RF coil arrangement has a minimum diameter IDS,
such that: AD 1 >IDS
ADV<IDS and
AD 2 <IDS.

16. The probe head assembly according to claim 15 , wherein the sheath element is gas-tight.

17. The probe head assembly according to claim 16 ,
wherein the RF coil arrangement is situated in an evacuated space, which is delimited by the sheath element, and/or
wherein the RF coil arrangement is cooled to a cryogenic temperature T≤100 K.

18. A method for measuring a measurement substance, comprising:
providing a probe head assembly according to claim 15 ,
arranging the rotor in the stator, and
rotating the rotor about the rotation axis at a frequency of at least 1 kHz.

19. The method according to claim 18 , further comprising:
selecting a gas flow on the first radial bearing and a gas flow on the second radial bearing such that an at least approximately equal bearing stiffness is achieved for the first radial bearing and the second radial bearing.

Assignees

• Bruker Biospin Ag
• Bruker Switzerland Ag

Inventors

• Guidoulianov Jevgeni
• Freytag Nicolas

Classifications

• G01R33/307 Primary

  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

• G01R33/46

  NMR spectroscopy · CPC title