Lockable rotor for cryogenic NMR spectroscopy

Abstract

Lockable rotor for cryogenic NMR spectroscopy. The present invention relates to a rotor (1) for NMR spectroscopy, comprising a tubular body (2) having, at at least one of its longitudinal ends (4, 5), or the open end, a cavity (3) that is open to the outside for containing a sample and a locking relief (6, 14), a stopper (7, 15) configured to fit into one of the open ends of the tubular body to seal the tubular body, the stopper (7, 15) having a locking relief (11, 18) that engages with the relief of the body to lock the stopper in the body when the stopper is fitted into the body, and / or a lid (22, 27) configured to fit around one of the open ends of the tubular body to seal the tubular body, the lid (22, 27) having a thermal contraction coefficient that is equal to or greater than the thermal contraction coefficient of the tubular body.

Description

[Technical Field]

[0001] The present invention relates to the field of nuclear magnetic resonance (NMR) spectroscopy.

[0002] The present invention more particularly relates to a rotor that contains a sample to be analyzed by NMR. [Background technology]

[0003] Nuclear magnetic resonance (NMR) spectroscopy is a non-destructive analytical method that uses the phenomenon of nuclear magnetic resonance (NMR), particularly to elucidate molecular structure.

[0004] NMR occurs when atomic nuclei with non-zero spin are placed in a static magnetic field and excited by electromagnetic radiation. This method is particularly used in organic chemistry, inorganic chemistry, biology, and materials science.

[0005] In solid-state NMR spectroscopy, it is common to place the sample to be analyzed in a rotor for rotating the sample about an axis 44' tilted by 54°, referred to as the magic angle, relative to the static magnetic field.

[0006] The rotor, also called a sample holder, typically comprises a tubular body containing the conditioned sample in powder form and at least one bung for closing the tubular body. A carrier fluid levitates the rotor, which is disposed on a stator. The rotor is generally driven to rotate pneumatically. To ensure rotation, the rotor comprises blades at one of its longitudinal ends, forming a turbine that generally defines the circumference of the bung. A driving fluid propelled into the turbine thus rotates the rotor at frequencies ranging from a few kHz to tens of kHz.

[0007] To ensure physical integrity and pneumatic rotation over this speed range, the tubular body of the rotor is typically fabricated from a ceramic, for example an alloy containing zirconium and yttrium. The tubular body may also be made from sapphire. These materials have the advantage that their low magnetic susceptibility prevents NMR measurements from being affected by noise.

[0008] The material from which the turbine is made must withstand the mechanical stresses induced by the high rotational speeds. The material must also be sufficiently elastic so that the plug can be positioned in assembly with the tubular body while generating enough clamping force to ensure the plug is held in place. Clearly, any change in speed at these high rotational speeds creates a torque that tends to dislodge the plug from the tubular body. A commonly used material for the plug and turbine is Vespel®.

[0009] Furthermore, it is known that increasing the strength of the magnetic field, increasing the rotation speed of the rotor and / or using the phenomenon of dynamic nuclear polarization (DNP) makes it possible to improve the sensitivity and resolution of NMR spectroscopy.

[0010] It has been proven that lower temperatures during NMR analysis result in a higher signal-to-noise ratio and a higher gain due to the DNP phenomenon. Therefore, high-resolution NMR spectrometers generally operate at low temperatures, especially around 100 K. Reference [1] describes an NMR spectrometer that uses the DNP phenomenon and operates at temperatures below 100 K.

[0011] Previously, the materials that make up the tubular body and the stopper have different thermal contraction coefficients. This leads to a shrinkage difference between the tubular body and the stopper during a temperature drop, with the stopper shrinking more than the tubular body. This shrinkage difference reduces the clamping force of the stopper on the tubular body to practically zero for temperatures of approximately 100 K. As a result, at these temperatures, even a slight change in the rotor speed results in a torque that tends to disengage the stopper from the tubular body. Therefore, the turbine is no longer effective in rotating the entire rotor, and the stopper no longer closes the tubular body, potentially resulting in the loss of the sample.

[0012] To solve this problem, one could consider increasing the clamping force between the plug and the tubular body at ambient temperature, but this solution is not feasible because it would make it impossible to manually introduce the plug into the tubular body and would make it more complicated or even impossible to remove the plug without damaging the tubular body after the NMR measurement.

[0013] U.S. Patent No. 10,914,799 (B2) describes a rotor for NMR spectroscopy, which comprises a tubular body and a bung with a hub made of a material with a negative thermal contraction coefficient. The hub therefore expands as the temperature decreases, making it possible to maintain sufficient tightening torque to tighten the bung in the tubular body for performing low-temperature NMR spectroscopy. However, the manufacture of the bung in U.S. Patent No. 10,914,799 (B2) is particularly complex, particularly because the bung is of very small size, requiring extremely precise machining and preparation.

[0014] Therefore, there is a need for a rotor adapted for cryogenic NMR spectroscopy that overcomes the aforementioned drawbacks. In particular, there is a need for a rotor adapted for cryogenic NMR spectroscopy that is simple to manufacture and in which the stoppers do not become dislodged from the tubular body during rotation of the rotor at cryogenic temperatures. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] US Patent No. 10,914,799(B2) Summary of the Invention [Problem to be solved by the invention]

[0016] It is an object of the present invention to at least partially address this need. [Means for solving the problem]

[0017] To that end, the present invention provides a rotor for nuclear magnetic resonance (NMR) spectroscopy, extending along a longitudinal axis, comprising: a tubular body open towards the outside at least at one of its longitudinal ends, referred to as the open end, and provided with a cavity intended to contain a sample to be analyzed by NMR, and provided with at least one locking relief inside; - at least one plug configured to be at least partially fitted into one of the open ends of the tubular body to close the tubular body, the plug comprising locking reliefs complementary in shape to the reliefs of the tubular body so that when the plug is fitted into the body, the locking reliefs engage with each other to lock the plug in the body; and / or - at least one lid configured to be fitted at least partially around one of the open ends of the tubular body to close the tubular body, the lid having a thermal contraction coefficient that is equal to or greater than the thermal contraction coefficient of the tubular body to lock the lid on the body during operation of the rotor; The present invention relates to a rotor comprising:

[0018] The thermal contraction coefficient of a component corresponds to its ability to shrink during a drop in temperature: the higher the thermal contraction coefficient, the greater the shrinkage.

[0019] Preferably, the locking relief of the tubular body is a radial groove provided on the inside in the thickness of the tubular body, and the locking relief of the plug is a radial ridge on the outer periphery of the plug, arranged to clip into the groove when the plug is fitted to the body.

[0020] Alternatively, the locking relief of the plug may be a groove provided in the thickness at the radial periphery of the plug, and the locking relief of the tubular body may be a radially inner ridge arranged to clip into the groove when the plug is fitted to the body.

[0021] Preferably, the grooves and ridges each have an annular shape.

[0022] Preferably, the grooves have a depth that is greater than or equal to 0.1 mm and / or the ridges have a height that is greater than or equal to 0.1 mm.

[0023] Preferably, the plug comprises a cover and a sleeve configured to be fitted onto the tubular body with the cover protruding, preferably in abutment, at the open end of the tubular body, the sleeve comprising, on its outer periphery, a locking relief for the plug.

[0024] Preferably, the sleeve is segmented, preferably comprising at least two slots extending along the length of the sleeve.

[0025] Preferably, the sleeve has a length between 1.2 mm and 1.8 mm.

[0026] Preferably, the sleeve has an outer diameter greater than the opening diameter of the open end, for example, the outer diameter of the sleeve is between 2.4 mm and 2.7 mm.

[0027] Preferably, the difference between the outer diameter of the cover and the outer diameter of the body at its open end is 0.05 mm or less. Preferably, the outer diameter of the cover is substantially equal to the outer diameter of the body at its open end.

[0028] Preferably, the rotor comprises an insert configured to be received in the sleeve so as to press the sleeve against the wall of the cavity, thereby mechanically locking the bung that is engaged in the body.

[0029] Preferably, the cover comprises a threaded opening that opens into the sleeve, the insert being adapted to be threaded into said opening.

[0030] Preferably, the insert is made from a polymer, preferably polyetheretherketone.

[0031] Preferably, the closure comprises a cover and a hollow sleeve configured to fit around the open end of the tubular body with the cover protruding therefrom.

[0032] Preferably, the sleeve is configured to fit tightly around the tubular body.

[0033] Preferably, the difference between the outer diameter of the cover and the outer diameter of the sleeve is 0.05 mm or less. Preferably, the outer diameter of the cover is substantially equal to the outer diameter of the sleeve.

[0034] Preferably, the portion of the tubular body around which the lid is intended to fit, referred to as the fitting portion, has an outer diameter that is reduced relative to the outer diameter of the remainder of the tubular body.

[0035] Preferably, the difference between the outer diameter of the sleeve of the lid and the outer diameter of the tubular body beyond the fitting portion of the tubular body is 0.05 mm or less. Preferably, the outer diameter of the sleeve is substantially equal to the outer diameter of the tubular body beyond the fitting portion of the tubular body.

[0036] Preferably, the stoppers and / or caps are made from a plastic material, preferably a polyimide-based polymer such as Vespel®. Advantageously, stoppers and / or caps made from these materials have very low magnetic susceptibility, which limits noise during NMR spectroscopy. Furthermore, these materials are resistant to mechanical stress due to the high rotational speeds during NMR spectroscopy. These materials are also flexible, making it easy to fit the stoppers and / or caps.

[0037] Preferably, the rotor comprises blades forming a turbine.

[0038] According to a first embodiment, the cavity may be open only at a single end of the tubular body, called the open end, and the rotor comprises a plug or lid according to the above to close said open end.

[0039] The turbine may be enclosed by the plug or lid. Preferably, the vanes are formed in the plug cover or lid cover.

[0040] Alternatively, the rotor may comprise a cylindrical component on which the turbine blades are formed, the cylindrical component being configured to be secured, preferably by an interference fit, at the end of the tubular body opposite the open end. The cylindrical component may be made from plastic, preferably a polyimide-based plastic such as Vespel®.

[0041] According to a second embodiment, the cavity may be open at two ends of the tubular body, referred to as the open ends, and the rotor comprises two plugs according to the above for closing each of the open ends, with at least one of the plugs comprising a turbine. Preferably, the vanes are formed on the cover of the plug comprising the turbine. Preferably, the cover of the plug without the turbine is relatively smooth.

[0042] According to a third embodiment, the cavity may be open at two ends of the tubular body, referred to as the open ends, and the rotor comprises two lids according to the above for closing each of the open ends, with at least one of the lids comprising a turbine. Preferably, vanes are formed on the cover of the lid comprising the turbine. Preferably, the cover of the lid not comprising the turbine is relatively smooth.

[0043] According to a fourth embodiment, the cavity may be open at two ends of the tubular body, referred to as the open ends, and the rotor comprises a plug and lid as described above, a plug with a turbine, and / or a lid with a turbine, to close each of the open ends. Preferably, blades are formed on the cover of the plug with a turbine and / or the lid. Preferably, the cover of the plug or lid without the turbine is relatively smooth.

[0044] Preferably, the tubular body has a cylindrical shape with a length between 10 mm and 20 mm and / or an outer diameter between 0.7 mm and 4.0 mm.

[0045] Preferably, the open end has an opening diameter between 0.5 mm and 3.6 mm.

[0046] Preferably, the tubular body is made of a ceramic, preferably a zirconium-based ceramic, such as a mixture of zirconium and yttrium. Advantageously, bodies made of these materials have very low magnetic susceptibility, which limits noise during NMR spectroscopy. Furthermore, these materials are resistant to mechanical stress due to the high rotation speeds during NMR spectroscopy.

[0047] Preferably, the rotor weighs 1 g or less.

[0048] The invention also relates to a spectrometer for nuclear magnetic resonance (NMR) spectroscopy, comprising a rotor according to the invention.

[0049] Thus, the present invention essentially resides in a rotor for nuclear magnetic resonance spectroscopy, comprising stoppers and / or lids for closing the cavities of the tubular body. The stoppers and / or lids are adapted to remain fitted to or around the tubular body even in the event of a severe drop in temperature that causes differential shrinkage between the stoppers, the respective lids, and the tubular body. During NMR spectroscopy, the stoppers and / or lids remain fixed to the tubular body even in the event of changes in the rotor's rotation speed that result in potentially significant rotational torque between the stoppers, the respective lids, and the tubular body.

[0050] Furthermore, rotors according to the present invention are simple to manufacture and do not require precision machining, which can prove to be expensive.

[0051] Further advantages and features will become better apparent from the detailed description given by way of non-limiting example with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0052] [Figure 1] 1 is a schematic view in longitudinal section of a rotor for NMR spectroscopy according to the invention, in which the rotor comprises a bung and a tubular body with an opening at one end and a closed other end. [Figure 2] 1 is a schematic view in longitudinal section of a rotor for NMR spectroscopy according to the invention, in which the rotor comprises two bungs and a tubular body with an opening at each of its ends; FIG. [Figure 3] 1 is a schematic view in longitudinal section of a rotor for NMR spectroscopy according to the invention, in which the rotor comprises a lid and a tubular body with an opening at one end and a closed other end. [Figure 4] 1 is a schematic view in longitudinal section of a rotor for NMR spectroscopy according to the invention, in which the rotor comprises two lids and a tubular body with an opening at each of its ends; FIG. [Figure 5]1 is a schematic diagram in longitudinal section of a rotor for NMR spectroscopy according to the present invention, in which the rotor comprises a lid and a tubular body with an opening at one end and a closed end at the other, fixed to a cylindrical component forming a turbine. DETAILED DESCRIPTION OF THE INVENTION

[0053] For reasons of clarity, the various elements in the figures are shown to scale and the actual dimensions of the various parts are not necessarily respected.

[0054] 1 shows an embodiment of a rotor 1 of longitudinal axis X for NMR spectroscopy according to the invention. The rotor 1 comprises a hollow, tubular body 2 with a base and a cavity 3 extending over part of the length of the body 2. The base cavity 3 is open at a longitudinal end 4 of the body 2. The closed longitudinal end 5 of the body 2 may be flat-bottomed. The body 2 comprises, near the open end 4, a locking groove 6 provided on the inner periphery of the cavity 3 in the thickness of the body 2.

[0055] The rotor 1 also comprises a plug 7 comprising a cover 8 and a split sleeve 9 in the longitudinal continuation of the cover 8. The plug 7 is preferably one piece. The cover 8 has an outer diameter greater than the inner diameter of the body 2 which defines the cavity 3. The outer diameter of the cover 8 is significantly greater than the outer diameter of the split sleeve 9, thereby forming a shoulder. The cover 8 has blades 10 on its radial periphery, forming a turbine. The split sleeve 9 has a locking ridge 11 in the form of a ring on its radial periphery.

[0056] The split sleeve 9 is configured to fit into the cavity 3 of the body 2. The slots in the sleeve 9 make the sleeve 9 flexible and facilitate insertion of the sleeve 9 into the cavity 3.

[0057] During fitting, the locking ridges 11 clip into the locking grooves 6, thereby ensuring the mechanical locking of the plug 7 in the body 2.

[0058] When the sleeve 9 is inserted into the cavity 3 and locked, the cover 8 abuts against the body 2 .

[0059] The depth of the grooves 6 and the height of the ridges 11 are selected so that the ridges 11 remain clipped in the grooves 6 despite differential shrinkage between the plug 7 and the body 2 during a decrease in temperature, for example from a temperature of 293 K down to a temperature below 100 K, such as from a temperature between 10 K and 80 K.

[0060] Furthermore, the cover 8 is provided with a longitudinal through opening 13 which is threaded over at least part of the length of the cover 8 and over the length of the split sleeve 9 .

[0061] Once the split sleeve 9 is fitted onto the body 2 , the threaded insert 12 can be screwed into the threaded opening 13 until it is inserted into the split sleeve 9 .

[0062] The insert 12 screwed in this way ensures the mechanical locking of the split sleeve 9 locked in the cavity 3 .

[0063] In the embodiment shown in FIG. 1, the rotor 1 has a length equal to 17 mm, a diameter equal to 3.2 mm and a total mass equal to 0.1 g.

[0064] Figure 2 shows another embodiment of a rotor 1 for NMR spectroscopy according to the invention. The rotor 1 is similar to the one shown in Figure 1 except for the fact that the cavity 3 of the body 2 is a through cavity, so that the other end 5 of the body 2 is open. The body 2 comprises a second locking groove 14 provided in the thickness of the body 2 on the inner periphery of the cavity 3, near the other open end 5.

[0065] The rotor 1 also comprises a second plug 15 comprising a cover 16 and, at the longitudinal continuation of the cover 16, a split sleeve 17. The cover 16 has an outer diameter at the open end 5 that is larger than the opening diameter of the cavity 3. The outer diameter of the cover 16 is significantly larger than the outer diameter of the split sleeve 17, thereby forming a shoulder. The cover 16 has a relatively smooth outer surface. The split sleeve 17 comprises a locking ridge 18 in the form of a ring on its radial periphery.

[0066] Split sleeve 17 is configured to fit into cavity 3 of body 2. Slots in sleeve 17 make sleeve 17 flexible and facilitate insertion of sleeve 17 into cavity 3. During fitting, ridges 18 clip into second grooves 14, thereby ensuring mechanical locking of second plug 15 in body 2. When sleeve 17 is inserted into cavity 3, cover 16 abuts open end 5 of body 2.

[0067] The depth of the second groove 14 and the height of the ridge 18 are selected so that the ridge 18 remains clipped in the second groove 14 despite differential shrinkage between the second plug 15 and the body 2 during a decrease in temperature, for example from a temperature of 293 K down to a temperature of 100 K or less.

[0068] Additionally, the cover 16 is provided with a longitudinal through opening 20 that is threaded over at least a portion of the length of the cover 16 and the length of the split sleeve 17 .

[0069] Once the split sleeve 17 is fitted onto the body 2 , the threaded insert 19 can be screwed into the threaded opening 20 until it is inserted into the split sleeve 17 .

[0070] The insert 19 screwed in this way ensures the mechanical locking of the split sleeve 17 locked in the cavity 3 .

[0071] 3 shows another embodiment of a rotor 1 of longitudinal axis X for NMR spectroscopy according to the invention. The rotor 1 comprises a hollow, tubular body 2 with a base and a cavity 3 extending over part of the length of the body 2. The base cavity 3 is open at a longitudinal end 4 of the body 2. The closed longitudinal end 5 of the body 2 may be flat-bottomed. At its open longitudinal end 4, the body 2 also comprises a fitting portion 21 with an outer diameter that is reduced relative to the outer diameter of the remainder of the body 2, forming a shoulder.

[0072] The rotor 1 also comprises a lid 22 comprising a cover 23 and a sleeve 24 in the longitudinal continuation of the cover 23. The cover 23 has blades 25 on its radial periphery, forming a turbine.

[0073] The sleeve 24 has an opening 26 adapted to fit around the fitting portion 21 to close the cavity 3 to ensure retention of the sample contained in the body 2. Fitting is performed manually or automatically at a first temperature, for example ambient temperature.

[0074] The sleeve 24 is fabricated from a material having a thermal contraction coefficient greater than the thermal contraction coefficient of the material comprising the mating portion 21. Thus, during a temperature decrease, such as to a second temperature below 100 K, the differential contraction between the sleeve 24 and the mating portion 21 creates a locking force by clamping the lid 22 around the body 2. This clamping force ensures a mechanical hold between the lid 22 and the body 2 during cryogenic NMR spectroscopy.

[0075] Figure 4 shows another embodiment of a rotor 1 for NMR spectroscopy according to the invention. The rotor 1 is similar to the one shown in Figure 3, except for the fact that the cavity 3 of the body 2 is a through-hole and the rotor 1 is provided with a second lid 27. The end 5 is therefore open in this case. At this open end 5, the body 2 is provided with a second fitting portion 28 having an outer diameter that is reduced relative to the outer diameter of the remainder of the body 2, forming a shoulder.

[0076] The second lid 27 comprises a cover 29 and a sleeve 30 in the longitudinal continuation of the cover 29. The cover 29 has a relatively smooth outer surface. The sleeve 30 comprises an opening 31 adapted to fit around the fitting portion 28 to close the open end 5. Fitting can be performed manually or automatically at a first temperature, such as 293K.

[0077] The sleeve 30 is fabricated from a material having a thermal contraction coefficient greater than the thermal contraction coefficient of the material comprising the mating portion 28. Thus, during a temperature decrease, such as to a second temperature below 100 K, the differential contraction between the sleeve 30 and the mating portion 28 creates a locking force by clamping the second lid 27 around the body 2. This clamping force ensures retention of the second lid 27 with the body 2 during cryogenic NMR spectroscopy.

[0078] 5 shows another embodiment of a rotor 1 for NMR spectroscopy according to the invention. The rotor 1 comprises a hollow body 2 of tubular shape with a closed-end cavity 3. The body 2 comprises a fitting 28 at its open end 5. A plug 27 is provided to fit around said fitting 28 and thereby close the open end 5.

[0079] The body 2 has a protruding portion at its closed end 4 that forms a tenon 32. The rotor 1 also has a cylindrical element 33 with a mortise 34 and blades 35 on its outer radial surface that form a turbine. The mortise 34 can be fixed by an interference fit around the tenon 32, thereby locking the cylindrical element 33 in the body 2. The interference fit can be achieved at an ambient temperature of approximately 293 K. During a temperature decrease, such as to a temperature of 100 K or less, the tenon 32 remains locked in the mortise 34, ensuring the fixation of the cylindrical element 33 to the body 2.

[0080] 5, loading of the sample into cavity 3 is effected via open end 5. There is therefore a lid 27 which ensures that cavity 3 is closed during NMR spectroscopy. Advantageously, lid 27 has a cover 29 with a relatively smooth surface, which allows cover 29 to be exposed to a lesser extent to the driving fluid of the spectrometer and therefore more damped to changes in the rotational speed of rotor 1.

[0081] Other variations and improvements may be envisaged without departing from the scope of the invention.

[0082] (References) [1]: Yoh Matsuki and Toshimichi Fujiwara, "Cryogenic Platforms and Optimized DNP sensitivity", eMagRes, 2018, vol. 7: 9~24 [Explanation of symbols]

[0083] 1 rotor 2 Bottomed body 3 Bottomed cavity 4 Open longitudinal end, open end 5 Closed longitudinal end, other open end 6 Locking groove 7 Stopper 8 Cover 9 Split Sleeve 10 Feathers 11 Locking ridge 12 threaded inserts 13 Through opening, threaded opening 14 Second locking groove 15 Second Stopper 16 Cover 17 Split sleeve 18 Locking ridge 19 Threaded Insert 20 Through opening 21 Fitting part 22 Lid 23 Cover 24 sleeve 25 Feather 26 Aperture 27 Second lid, stopper 28 Second fitting part 29 Cover 30 sleeves 32 Tenon 33 Cylindrical Components 34 Mortise 35 Feather

Claims

1. A rotor (1) for nuclear magnetic resonance (NMR) spectroscopy extending along a longitudinal axis (X), a tubular body (2) open towards the outside at least at one of its longitudinal ends (4, 5), called the open end, and comprising a cavity (3) intended to contain a sample to be analyzed by NMR, and comprising at least one locking relief (6, 14) inside; at least one plug (7, 15) configured to be at least partially fitted into one of the open ends of the tubular body to close the tubular body, the plug comprising locking reliefs (11, 18) of a shape complementary to the reliefs of the tubular body so that when the plug is fitted into the body, the locking reliefs engage with each other to lock the plug in the body, the locking reliefs of the tubular body being radial grooves provided on the inside in the thickness of the tubular body, and the locking reliefs of the plug being radial ridges on the periphery of the plug arranged to clip into the grooves when the plug is fitted into the body, the depth of the grooves and the height of the ridges being selected such that the ridges remain clipped into the grooves despite differential shrinkage between the plug and the body during a temperature drop in the range from 293 K down to a maximum of 100 K; and / or at least one lid (22, 27) configured to be fitted at least partially around one of the open ends of the tubular body to close the tubular body, the lid having a thermal contraction coefficient equal to or greater than the thermal contraction coefficient of the tubular body so as to lock the lid around the tubular body during operation of the rotor, the lid comprising a cover (23, 29) and a hollow sleeve (24, 30) configured to be fitted around the open end of the tubular body with the cover protruding, the part of the tubular body around which the lid is intended to be fitted, referred to as the fitting portion (21, 28), having an outer diameter that is reduced relative to the outer diameter of the remainder of the tubular body, the difference between the outer diameter of the sleeve of the lid and the outer diameter of the tubular body beyond the fitting portion of the tubular body being 0.05 mm or less; A rotor (1) comprising:

2. A rotor (1) for nuclear magnetic resonance (NMR) spectroscopy extending along a longitudinal axis (X), a tubular body (2) open towards the outside at least at one of its longitudinal ends (4, 5), called the open end, and comprising a cavity (3) intended to contain a sample to be analyzed by NMR, and comprising at least one locking relief (6, 14) inside; at least one plug (7, 15) configured to be at least partially fitted into one of the open ends of the tubular body to close the tubular body, the plug comprising locking reliefs (11, 18) of a shape complementary to the reliefs of the tubular body so that when the plug is fitted into the body, the locking reliefs engage with each other to lock the plug in the body, the locking reliefs of the plug being grooves in the radially outer thickness of the plug and the locking reliefs of the tubular body being radially inner ridges arranged to clip into the grooves when the plug is fitted into the body, the depth of the grooves and the height of the ridges being selected such that the ridges remain clipped into the grooves despite differential shrinkage between the plug and the body during temperature drops in the range from 293 K down to a maximum of 100 K; and / or at least one lid (22, 27) configured to be fitted at least partially around one of the open ends of the tubular body to close the tubular body, the lid having a thermal contraction coefficient equal to or greater than the thermal contraction coefficient of the tubular body so as to lock the lid around the body during operation of the rotor, the lid comprising a cover (23, 29) and a hollow sleeve (24, 30) configured to be fitted around the open end of the tubular body with the cover protruding, the part of the tubular body around which the lid is intended to be fitted, referred to as the fitting portion (21, 28), having an outer diameter that is reduced relative to the outer diameter of the remainder of the tubular body, the difference between the outer diameter of the sleeve of the lid and the outer diameter of the tubular body beyond the fitting portion of the tubular body being 0.05 mm or less; A rotor (1) comprising:

3. 3. A rotor according to claim 1 or 2, wherein the plug comprises a cover (8, 16) and a sleeve (9, 17) adapted to be fitted onto the tubular body at the open end of the tubular body, preferably in abutment with the cover protruding, the sleeve comprising, on its outer periphery, the locking relief for the plug.

4. 4. The rotor according to claim 3, comprising an insert (12) configured to be received in the sleeve so as to press the sleeve against the wall of the cavity, thereby mechanically locking the plug that is engaged in the body.

5. A rotor according to any one of claims 1 to 4, wherein the plug and / or the lid are made from a plastic material, preferably a polyimide-based polymer such as Vespel®.

6. A rotor according to any one of claims 1 to 5, comprising blades (10, 25, 35) forming a turbine.

7. 7. A rotor according to any one of claims 1 to 6, wherein the tubular body has a cylindrical shape with a length between 10 mm and 20 mm and / or an outer diameter between 0.7 mm and 4.0 mm.

8. 8. A rotor according to any one of claims 1 to 7, wherein the open end has an opening diameter between 0.5 mm and 3.6 mm.

9. A rotor according to any one of the preceding claims, wherein the tubular body is made from a ceramic, preferably a zirconium-based ceramic, such as a mixture of zirconium and yttrium.

10. 10. A rotor according to any one of claims 1 to 9, wherein the rotor weighs 1 g or less.

11. A spectrometer for Nuclear Magnetic Resonance (NMR) spectroscopy, comprising a rotor (1) according to any one of claims 1 to 10.

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