NMR probe head with improved centering of the sample vial

Patent metadata

Field	Value
Publication number	US-9726735-B2
Application number	US-201414306320-A
Country	US
Kind code	B2
Filing date	Jun 17, 2014
Priority date	Jun 26, 2013
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

An NMR probe head ( 3 ) has a coil system ( 9 ) and a radial centering mechanism for a sample vial ( 4 ) having two centering devices spaced axially from each other to center the sample vial in the radial direction only. The first centering device ( 5 ) is disposed above the receiver coil system and at least one further centering device ( 6 ) is disposed axially above the coil system with an axial spacing (d) above the first centering device. The first and second centering devices restrict the radial scope for movement of the sample vial to such an extent that the sample vial cannot touch an endangered space ( 7 ) during the entire duration of transport of the sample vial to its measuring position, thereby precluding damage to the probe head components in the endangered space by the sample vial.

First claim

We claim:

1. An NMR probe head for analyzing a substance to be measured, the substance being disposed in a longitudinal sample vial closed at one end and filled with that substance, the probe head comprising:
an NMR coil system disposed around a vertical z axis, the NMR coil system being fixed radially, with respect to the z axis, relative to the NMR probe head;
a first centering device for radially centering the sample vial relative to the z axis, said first centering device having a first passage opening for the sample vial that centers the sample vial in a radial direction only, wherein, in a z direction, said first centering device is disposed above said NMR coil system and is radially fixed with respect to the z axis; and
at least one second centering device, said second centering device having a second passage opening for the sample vial that centers the sample vial in the radial direction only, said second centering device being disposed axially above the NMR coil system and spaced apart from said first centering device in an axial direction of the z axis by an axial spacing with respect to the z axis, said axial spacing being selected and sizes as well as geometric shapes of said first and said second passage openings being designed such that, during an entire duration of transport of the sample vial into a measuring position in the NMR probe head, said first centering device and said second centering device cooperate with the sample vial to restrict a radial scope for movement of the sample vial relative to the z axis to such an extent that the sample vial cannot touch a predefined hollow cylindrical space, which extends axially with respect to the z axis in a region of said NMR coil system, which extends above and/or below said NMR coil system and which at least partially extends radially within said NMR coil system, wherein said second centering device is mechanically connected to the NMR Probe head and a radially innermost NMR coil of said NMR coil system and/or a holder structure for said innermost NMR coil is/are disposed in said hollow cylindrical space, wherein said holder structure for said innermost NMR coil is disposed in said hollow cylindrical space, and at least part of said first centering device extends radially between said holder structure and the sample vial in a measuring position thereof.

2. The NMR probe head of claim 1 , wherein a cylindrical tube is disposed in said hollow cylindrical space and surrounds the sample vial in a measuring position thereof.

3. The NMR probe head of claim 1 , wherein a cross section of at least one of said first and said second centering devices is geometrically designed such that a temperature-control gas can flow between the sample vial in a measuring position thereof and said first and second centering devices, wherein a temperature-control gas flow through said first and said second centering devices is blocked by no more than 70% in total, as viewed in a cross-sectional plane perpendicular to the z axis.

4. The NMR probe head of claim 1 , wherein said first centering device comprises a radial inner guide, a cylindrical tube preferably acting as RF shielding and an upper end stop edge adapted to rest on an upper end face of a cylindrical coil glass.

5. The NMR probe head of claim 1 , wherein said first centering device comprises a radial inner guide having multiple radial cutouts extending along the z axis in the axial direction and/or has slots disposed along the z direction.

6. The NMR probe head of claim 5 , wherein cams, raised in the radial direction, are provided on bars between said slots, said cams being dimensioned in such a way that said first centering device is clamped in the radial direction when inserted into said holder structure for said radially innermost NMR coil of the NMR coil system.

7. The NMR probe head of claim 1 , further comprising a third centering device disposed with axial spacing In the z direction above said first centering device and below said second centering device.

8. The NMR probe head of claim 1 , further comprising a third centering device disposed axially below said NMR coil system.

9. The NMR probe head claim 1 , further comprising at least one positioning device for axially positioning the sample vial, which, in the measuring position, is disposed below or above said NMR coil system.

10. The NMR probe head of claim 9 , wherein said positioning device is disposed axially below said NMR coil system and comprises an end stop part on which the sample vial rests in an operating position thereof.

11. The NMR probe head of claim 1 , wherein said first and second centering devices and are mechanically rigidly connected to each other and/or to a holder structure for said NMR coil system.

12. The NMR probe head of claim 1 , wherein at least one of said first and second centering devices has a funnel-shaped passage opening to receive the sample vial.

13. The NMR probe head of claim 1 , wherein at least one of said first and second centering devices is designed in such a way that a region thereof that can touch the sample vial in the measuring position has an axial extent of 0.05 D to 0.6 D, wherein D Is a radial diameter of the sample vial.

14. The NMR probe head of claim 1 , wherein at least one of said first and second centering devices consists of a material, which has a hardness that is less than a hardness of materials from which the sample vial is manufactured, less than a hardness of borosilicate glass or less than a hardness of fused silica.

15. The NMR probe head of claim 1 , wherein at least one of said first and second centering devices consists of a material that has a conductivity of <10 −8 S/m.

16. The NMR probe head of claim 1 , wherein at least one of said first and second centering devices consists of a material that has a magnetic susceptibility of <1.0 ppm.

17. The NMR probe head of claim 1 , wherein a temperature-control gas flowing around the sample vial in at least one of said first and second centering devices does not flow between said respective first or second centering device and the sample vial, rather is guided through air outlet holes offset radially away from the z axis.

18. The NMR measurement configuration having the NMR probe head of claim 1 , with an NMR magnet system, a shimming system, a turbine, and a device for transporting the sample vial from outside the NMR magnet system into a measuring position of the sample vial in said NMR probe head.

19. An NMR probe head for analyzing a substance to be measured, the substance being disposed in a longitudinal sample vial closed at one end and filled with that substance, the probe head comprising:
an NMR coil system disposed around a vertical z axis, the NMR coil system being fixed radially, with respect to the z axis, relative to the NMR probe head;
a first centering device for radially centering the sample vial relative to the z axis, said first centering device having a first passage opening for the sample vial that centers the sample vial in a radial direction only, wherein, in a z direction, said first centering device is disposed above said NMR coil system and is radially fixed with respect to the z axis; and
at least one second centering device, said second centering device having a second passage opening for the sample vial that centers the sample vial in the radial direction only, said second centering device being disposed axially above the NMR coil system and spaced apart from said first centering device in an axial direction of the z axis by an axial spacing with respe

Assignees

• Bruker Biospin Ag

Inventors

• Schmidig Daniel
• Al Adwan Stojilkovic Danijela
• Wilhelm Dirk

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