Device for parameterizing a probe having two sealed enclosures and its use in the field of low-temperature nuclear magnetic resonance (NMR) spectroscopy - Patent Application 20070122999

Abstract

The present invention relates to an apparatus (1) comprising a sealed housing (2) including a sheath (6) that opens to the outside (7) of the sealed housing, a cryogenic chamber (3) disposed in the sealed housing and including an opening (19) that opens into the sealed housing, an adjustment rod (25) translatably mounted within the cryogenic chamber for adjusting the position of an element contained in the cryogenic chamber, a transmission bar (10) sealingly passing through the sheath and translatably movable along the longitudinal axis of the sheath by an element outside the sheath, the transmission bar being connected to the adjustment rod for transmitting translation of the bar to the rod and vice versa, and a corrugated bellows (22) sealingly mounted to the transmission bar around the opening for sealing the cryogenic chamber.

Description

[Technical Field]

[0001] The present invention relates to a system having two enclosures, and in particular to a system comprising a low temperature chamber, known as a cryogenic chamber, contained in a sealed vacuum enclosure.

[0002] Although described for use in the field of nuclear magnetic resonance (NMR) spectroscopy, the invention can be implemented in any system having two sealed enclosures, i.e., one sealed enclosure placed inside another sealed enclosure. [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 analyze molecular structure. NMR occurs when atomic nuclei with non-zero spin are placed in a static magnetic field and excited by electromagnetic waves. This method is used, among other things, in organic chemistry, inorganic chemistry, biology, and materials science.

[0004] In solid state NMR spectroscopy, it is usual to place the sample to be analyzed on a rotor in order to rotate it about an axis tilted by 54° 44' relative to the static magnetic field, known as the magic angle.

[0005] It is also known that it is possible to improve the sensitivity and resolution of NMR spectroscopy by increasing the strength of the magnetic field, increasing the speed of the rotor, and / or using the phenomenon of dynamic nuclear polarization (DNP).

[0006] It has been proven that during NMR analysis, the lower the temperature, the greater the signal-to-noise ratio and the higher the gain due to the DNP phenomenon. High-resolution NMR spectrometers therefore generally operate at low temperatures, especially around 100 K. Reference [1] describes an NMR spectrometer operating at temperatures below 100 K using the DNP phenomenon.

[0007] To achieve low temperatures, for example around 100 K or less, it is preferable for the NMR spectrometer to operate autonomously in a closed loop. An autonomously operating device is one that does not require a cryogenic fluid supply. A closed loop operating device is one in which the working fluid circulates without exposure to the external environment and without fluid movement outside the loop.

[0008] In an autonomous closed-loop NMR spectrometer, it is important to maintain high purity of the working fluid, i.e., it must be as free as possible from all kinds of impurities (gaseous, particulate solid, hydrocarbon-based, etc.).

[0009] An NMR spectrometer operating autonomously in a closed loop typically has two sealed enclosures, i.e., e.g., 10 -5 The probe comprises a sealed vacuum enclosure at a pressure of less than or equal to 100 mbar and a sealed chamber disposed in the sealed enclosure, which is pressurized to, for example, 4 bar, at a cryogenic temperature, for example around or even below 100 K. This arrangement of the cryogenic chamber within the sealed vacuum enclosure ensures excellent thermal insulation and thus makes it possible to perform NMR spectroscopy measurements at low or very low temperatures.

[0010] In addition, the magnetic field of an NMR spectrometer can be slightly modified as a function of the nuclei of the material being analyzed. For this purpose, the probe contains several components known as tuning capacitors, which are housed in a cryogenic chamber. Each tuning capacitor contains a movable core, which allows the impedance of the probe's coil to be precisely adjusted as a function of the core's position in the coil.

[0011] The placement of the tuning capacitors within the cryogenic chamber of the probe makes them difficult to access and therefore complicates their tuning.

[0012] Similarly, in such NMR spectrometers, the stator that allows the sample mounted on a rotor tilted at the magic angle to be rotated is located in the sealed cryogenic chamber of the probe and is therefore difficult to access.

[0013] One possible method for adjusting the tilt angle of the tuning capacitor and / or stator is to disassemble and then reassemble the sealed enclosure and cryogenic chamber at ambient temperature. This method is laborious and time-consuming, and requires purging of the cryogenic chamber after reassembly in order for the NMR spectrometer to operate autonomously in closed loop mode. In addition, this method is complex to implement because it requires predicting the electronic and mechanical changes that occur in the tuning capacitor and / or stator upon lowering to extremely low temperatures.

[0014] Therefore, there is a need for an apparatus that allows for easy and rapid adjustment of the tuning capacitor and / or stator tilt angle of an NMR spectrometer that includes a probe having two sealed enclosures.

[0015] More generally, there is a need for an apparatus suitable for easily and quickly adjusting and moving elements housed in a cryogenically operating chamber, which itself is disposed in a sealed enclosure. Summary of the Invention [Problem to be solved by the invention]

[0016] It is an object of the present invention to at least partially meet this / these needs. [Means for solving the problem]

[0017] To this end, the present invention provides a sealed housing, the sealed housing including at least one sheath emerging from an exterior of the sealed housing; a cryogenic chamber disposed in the sealed enclosure and including at least one opening emerging within the sealed enclosure; at least one adjustment rod translatably mounted within the cryogenic chamber for adjusting the position of an element contained within the cryogenic chamber; at least one transmission bar sealingly passing through the sheath, the transmission bar being translatably movable along the longitudinal axis of the sheath by an element arranged outside the sheath and connected to the adjustment rod such that translation of the bar is transmitted to the rod and vice versa; at least one corrugated bellows sealingly secured to the transfer bar around the opening for sealing the cryogenic chamber; The present invention relates to an apparatus comprising:

[0018] Preferably, the sheath includes a gland configured to be sealingly compressed over the delivery bar while allowing the delivery bar to translate.

[0019] Preferably, the gland includes at least one, preferably at least two seals, and a clamping ring configured to compress the seals on the transfer bar.

[0020] Preferably, the gland includes an annular chamber in which the seal is partially housed, the annular chamber having a diameter of 1.10 mm. -3 The pressure is below mbar.

[0021] Preferably, the sheath includes a guide sleeve configured to guide translation of the transfer bar and at least one immobilization means for preventing rotation of the transfer bar.

[0022] Preferably, the device comprises a thumbwheel accessible from outside the sheath and a translation mechanism configured to translate rotation of the thumbwheel into translation of the transmission bar along the axis of the sheath. Preferably, the transmission bar includes a threaded portion and the translation mechanism includes a nut or gear to form, together with the threaded portion, a jackscrew or rack and pinion system, respectively.

[0023] Preferably, the device includes a ball bearing configured to facilitate rotation of the thumbwheel.

[0024] The thumbwheel can be rotated manually and / or by a motor. The conversion mechanism can include a reduction gear configured to transfer rotation of the thumbwheel to an output rotation, wherein a ratio between the output rotational speed and the rotational speed of the thumbwheel is less than 1:15, and the conversion mechanism is configured to convert the output rotation into a translation of the transmission bar.

[0025] Preferably, the corrugated bellows is made from metal.

[0026] Preferably, the corrugated bellows is hermetically welded to the transmission bar.

[0027] Preferably, the device comprises an annular seal sealing the fixation of the corrugated bellows around the periphery of the opening.

[0028] According to a first alternative, the device may comprise a transmission cable, one end of which is fixed to the transmission bar and the other end of which is fixed to the adjustment rod.

[0029] Preferably, the device comprises a guide tube configured to guide the sliding of the transmission cable. Preferably, the guide tube extends along a curve, preferably in the shape of an S.

[0030] Preferably, the apparatus includes a return spring mounted around and secured to the adjustment rod for translating the adjustment rod toward the inside of the cryogenic chamber when the cable is slackened by translation of the transmission bar toward the inside of the cryogenic chamber.

[0031] According to a second alternative, the adjusting rod can be fixed directly to the transmission bar.

[0032] Preferably, the apparatus comprises at least one tuning capacitor disposed in the cryogenic chamber, the tuning capacitor including a core that can be translatably moved to vary the tuning capacitor, and an end of the adjustment rod opposite the end connected to the transmission bar is connected to the core and is preferably fixed.

[0033] Preferably, the apparatus comprises a stator disposed in a cryogenic chamber and mounted for rotation about a horizontal axis, and an adjustment rod connected to the stator, preferably fixed, such that translation of the adjustment rod causes rotation of the stator about the horizontal axis.

[0034] Preferably, the sealed enclosure is -5 The pressure is less than mbar.

[0035] Preferably, the cryogenic chamber is at a pressure of 1000 to 4000 mbar and / or a temperature below 30K.

[0036] Preferably, the apparatus forms a probe for a nuclear magnetic resonance (NMR) spectrometer. Preferably, the probe includes a stator and at least one adjustment rod, the translation of which changes the tilt of the stator, and / or at least one adjustment rod, the translation of which changes a tuning capacitor of the probe.

[0037] The invention therefore essentially consists of a device comprising a sealed housing, a cryogenic chamber arranged in the sealed housing, and an adjustment rod for positioning an element contained in the cryogenic chamber, which is connected to a transmission bar accessible from the outside, so that translation of one causes translation of the other and vice versa, even without a rigid connection between them. The adjustment rod and the transmission bar are assembled by a sealing bellows fixed in particular to the transmission bar, keeping the cryogenic chamber and the sealed housing sealed. Adjusting the position of the element contained in the chamber makes it possible, for example, to select the impedance of a tuning capacitor contained in the cryogenic chamber.

[0038] These externally adjustable components are easy to implement and have a small footprint.

[0039] In particular, the bellows, preferably in the form of corrugated bellows, ensure the sealing of the cryochamber both at ambient temperature and at low temperatures, e.g., temperatures below 100 K. The corrugated bellows also ensure sealing in the face of potentially large pressure and temperature differences between the sealed enclosure and the cryochamber. Additionally, the use of bellows ensures good thermal insulation between the sealed enclosure and the cryochamber.

[0040] Further advantages and features will become more clearly apparent on reading the detailed description given by way of non-limiting example with reference to the following figures. [Brief explanation of the drawings]

[0041] [Figure 1] 1 is a schematic longitudinal cross-section of a device according to the invention, the guide tube of which is straight and the corrugated bellows of which are subjected to an internal pressure greater than the external pressure. [Figure 2] 1 is a schematic longitudinal cross-section of an apparatus according to the invention, which is a probe for NMR spectroscopy, in which translation of an adjustment rod adjusts the tuning capacitor of the probe. [Figure 3] 1 is a schematic longitudinal cross-section of an apparatus according to the invention, which is a probe for NMR spectroscopy, in which the tilt angle of a stator of the probe is adjusted by translation of an adjustment rod. [Figure 4] 1 is a schematic longitudinal cross-sectional view of a device according to the invention, the guide tube of which extends in an S-shape and the corrugated bellows of which operates at an internal pressure greater than the external pressure. [Figure 5] 1 is a schematic longitudinal cross-sectional view of a device according to the invention, the guide tube of which extends in an S-shape and the corrugated bellows of which operates at an internal pressure that is smaller than the external pressure. DETAILED DESCRIPTION OF THE INVENTION

[0042] 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.

[0043] FIG. 1 shows an apparatus 1 according to the invention, which comprises a sealed enclosure 2 and a cryogenic chamber 3 housed in the sealed enclosure 2 .

[0044] The internal environment 4 of the sealed enclosure 2 is 10 -5 The pressure is below mbar.

[0045] The cryogenic chamber 3 is sealed and pressurized, for example to 4 bar, and is at a cryogenic temperature, for example around or even below 100 K. This arrangement of the cryogenic chamber 3 within the sealed enclosure 2 ensures good thermal insulation.

[0046] A thermally insulating support 5 supports the cryochamber 3 while limiting heat transfer.

[0047] The sealed housing 2 includes a sheath 6 that emerges at one end to an environment 7 external to the sealed housing 2 and at the other end to an environment 4 internal to the sealed housing 2. The sheath 6 includes a gland 8 and a guide sleeve 9.

[0048] A transmission bar 10 is inserted into the sheath 6, and the gland 8 is compressed around the transmission bar 10 to seal the sheath 6. The transmission bar 10 is mounted translatably along the central axis of the sheath.

[0049] The gland 8 includes three clamping rings 11 and two seals 12 housed in a hollow cylindrical structure 13. The inner diameter of the hollow cylindrical structure 13 is sufficient to allow the transmission bar 10 to pass therethrough. The clamping rings 11 are tightened to compress the seals 12 around the transmission bar, thus closing the sheath 6. Compression of the seals 12 reduces their inner diameter, which can therefore be smaller than the outer diameter of the transmission bar 10. The compression of the seals 12 can be adjusted using a spring plunger.

[0050] The gland 8 also includes an annular chamber 14 around the clamping ring 11 and seal 12. The annular chamber 14 is typically 1.10 -3 The pressure is reduced to a pressure of 1.10 mbar or less. The volume between the clamping ring 11 and the seal 12 and the volume between the two seals 12 are therefore 1.10 -3 Such a pressure makes it possible to ensure a better compression of the seal 12 and thus a better sealing of the sheath 6 closure.

[0051] In addition, the transmission bar 10 is prevented from rotating within the guide sleeve 9. To this end, the transmission bar 10 may include a pin 15 arranged in a slot made in the guide sleeve 9.

[0052] The device 1 is located outside the sealed housing 2 and includes a thumbwheel 16 rigidly connected to a nut 17 onto which the transmission bar 10 is threaded, forming a screw and nut system. This system 10, 17 is similar to a jackscrew and allows the rotation of the thumbwheel 16 to be converted into the translation of the transmission bar 10 along the central axis of the sheath. The thumbwheel 16 can be rotated manually or by a motor. Ball bearings 18 are located on either side of the nut 17 to facilitate the rotation of the thumbwheel 16.

[0053] The screw and nut system 10, 17 allows for precise and easy translation of the transmission bar 10. In addition, such a system ensures that the bar 10 is held in place even without rotation of the thumbwheel 16.

[0054] The cryogenic chamber 3 comprises an opening 19 around which is fixed, preferably screwed, a particularly straight guide tube 20 which extends into the sealed housing 2 .

[0055] An annular seal 21 seals the fixing of the guide tube 20 around the opening 19. The annular seal 21 may be an elastic seal with a C-shaped cross section. Alternatively, the annular seal 21 may be made of a metal wire, for example indium, which is particularly suitable for cryogenic temperatures. The annular seal 21 may be compressed between the guide tube 20 and the wall of the cryogenic chamber 3 with a compressive stress of up to 50 N / mm.

[0056] The device 1 includes a corrugated bellows 22, one end of which is sealingly fixed to the guide tube 20. The other end of the corrugated bellows 22 is sealingly fixed around the transmission bar 10 so that translation of the transmission bar 10 causes the corrugated bellows 22 to contract in one direction and expand in the other direction. The corrugated bellows 22 can be hermetically welded to the transmission bar 10 and / or the guide tube 20. These welds advantageously improve the seal, ensuring good sealing even at low temperatures, e.g., below 100 K, and withstanding large pressures and temperature differences.

[0057] In the embodiment shown in FIG. 1, pushing the transmission bar 10 towards the opening 19 causes the corrugated bellows 22 to contract, and conversely, pulling the transmission bar 10 outward causes the corrugated bellows 22 to expand.

[0058] The corrugated bellows 22 seals the opening 19 and seals the cryogenic chamber 3. The pressure on the inside of the corrugated bellows 22 is equal to the pressure in the cryogenic chamber 3. The pressure on the outside of the corrugated bellows 22 is equal to the pressure of the internal environment 4 of the sealed enclosure 2.

[0059] The corrugated bellows 22 is configured to withstand the difference between the pressure on its inside and the pressure on its outside. In particular, the wall thickness of the corrugated bellows 22 can be greater than or equal to 0.1 mm, preferably between 0.05 and 0.012 mm. In addition, such a thickness limits heat loss by conduction.

[0060] By way of example, the corrugated bellows 22 has a length of 80 mm and a diameter of 16 mm in the extended state.

[0061] The device 1 also includes a duct 23 around the corrugated bellows 22 which is configured to guide the contraction or expansion of the corrugated bellows 22. The duct 23 thus prevents the corrugated bellows 22 from buckling.

[0062] The device 1 includes a cable 24 fixed at one end to the transmission bar 10 and at the other end to an adjustment rod 25 .

[0063] The cable 24 is disposed in the corrugated bellows 22 and the guide tube 20. The adjustment rod 25 is disposed in the cryogenic chamber 3 facing the opening 19. Thus, when the transmission bar 10 is pulled towards the outside of the sealed housing 2, the cable 24 applies tension to the adjustment rod 25.

[0064] The device 1 includes a return spring 26, one end of which is fixed to the cryogenic chamber 3 and the other end of which extends around and is fixed to the adjustment rod 25. The return spring 26 makes it possible to keep the cable 24 taut when the transmission bar 10 is pushed towards the cryogenic chamber 3. This pushing causes the cable 24 to slacken, and the force of the return spring 26 causes the cable 24 to become taut again, simultaneously pushing the adjustment rod 25.

[0065] The cable 24 and the return spring 26 therefore transfer any translation of the transmission bar 10 along the axis of the sheath to a translation of the adjustment rod 25. As will be seen below, the translation of the adjustment rod 25 within the cryochamber 3 allows the elements contained in the cryochamber 3 to be accurately positioned.

[0066] The cable 24 is preferably made of a metallic material. Preferably, the cable 24 is multi-stranded and therefore has great flexibility, which facilitates its movement within the corrugated bellows 22 and the guide tube 20.

[0067] To limit heat loss by conduction, the cable 24 may have a diameter of 1 mm or less, preferably between 0.8 and 1.2 mm.

[0068] To ensure sufficient thermal and electrical insulation, the adjustment rod 25 may be made from epoxy glass.

[0069] FIG. 2 shows a device 1 according to the invention, forming a probe for NMR spectroscopy.

[0070] 1, the probe 1 includes a tuning capacitor 27 disposed in the cryogenic chamber 3. The tuning capacitor 27 includes a core 28 translatably mounted within the housing for varying the impedance of the tuning capacitor 27.

[0071] The housing of the tuning capacitor 27 is cylindrical, 60 mm long and 12 mm in diameter.

[0072] At its end opposite cable 24, adjustment rod 25 is fixed to core 28. Translation of adjustment rod 25 accordingly translates core 28 within the housing of tuning capacitor 27, thus adjusting the impedance of tuning capacitor 27. In other words, with the described transmission mechanism, the impedance of tuning capacitor 27 can be changed simply by turning thumbscrew 16.

[0073] By way of example, adjustment rod 25 may translate 0.7 mm for each complete rotation of thumbscrew 16.

[0074] The probe 1 also includes a stator 29 on which a rotor 30 for NMR spectroscopy is disposed. The stator 29 includes a coil 31 connected by electrical leads 32 to a tuning capacitor 27. The coil 31 is configured to generate a static magnetic field for NMR spectroscopy. By varying the impedance of the tuning capacitor 27, the static magnetic field generated by the coil 31 can be altered. It is therefore possible to adjust the static magnetic field during NMR spectroscopy of a sample contained in the rotor 30 as a function of the atomic nuclei of the material to be analyzed.

[0075] Figure 3 also shows a probe 1 for NMR spectroscopy according to the present invention, which differs from the device 1 shown in Figure 1 in that it includes a stepped reduction gear 34 located between the thumbwheel 16 and the nut 17.

[0076] The reduction gear 34 transfers the rotation of the thumbwheel 16 to an output rotation at a reduction ratio of less than 1:15, for example 1:19.

[0077] Similar to a jackscrew, the nut 17 and transmission bar 10 convert the output rotation into a translation of the transmission bar 10 along the axis of the sheath.

[0078] The reduction gear 34 therefore makes it possible to precisely adjust the translation of the transmission bar 10 and consequently of the adjustment rod 25 .

[0079] As an example, with reduction gear 34, adjustment rod 25 can translate 0.037 mm for each complete rotation of thumbscrew 16.

[0080] The probe 1 also includes a stator 29 for receiving a rotor 30 for NMR spectroscopy. The stator 29 includes coils 31 configured to generate a static magnetic field for NMR spectroscopy.

[0081] Stator 29 is mounted rotatably about its transverse axis 33. Adjustment rod 25 is fixed at its end opposite cable 24 to stator 29, and translation of adjustment rod 25 causes stator 29 to rotate about its transverse axis 33. With the described transmission mechanism, the tilt angle θ of stator 29 can therefore be adjusted by turning thumbscrew 16. The tilt angle θ of stator 29 corresponds to the angle between the longitudinal axis along which stator 29 extends and the static magnetic field for NMR spectroscopy.

[0082] By way of example, one complete rotation of the thumbscrew 16 corresponds to a rotation of the tilt angle θ of the stator 29 of 00° 04' 42". The probe 1 is therefore suitable for precisely adjusting the tilt angle θ of the stator 29 to 54° 44'.

[0083] Figure 4 shows a device 1 according to the invention. It differs from the device shown in Figure 2 in that the guide tube 20 does not extend straight, but in an S-shape, which makes it possible to reduce its footprint. In addition, this offsets the translation of the transmission bar 10 and the adjustment rod 25, thereby reducing the space required for said translation.

[0084] Figure 5 shows an apparatus 1 according to the invention. It differs from the apparatus shown in Figure 4 in that it is not a guide tube 20 that is fixed around the opening 19, but rather a corrugated bellows 22, one end of which is fixed around the opening 19 and extends into the cryogenic chamber 3. A flange 28 arranged at the end of the corrugated bellows 22 presses against annular seal 21 to seal the fixation of the corrugated bellows 22 around the opening 19. The other end of the corrugated bellows 22 is fixed, preferably welded, to the transfer bar 10 and to the guide tube 20. The guide tube 20 extends in an S-shape in the cryogenic chamber 3.

[0085] The corrugated bellows 22 thus seals the opening 19 and seals the cryochamber 3. The pressure on the inside of the corrugated bellows 22 is equal to the pressure of the internal environment 4 of the sealed enclosure 2. The pressure on the outside of the corrugated bellows 22 is equal to the pressure in the cryochamber 3.

[0086] The embodiment in Fig. 5 is advantageous when the pressure of the internal environment 4 is less than the pressure in the cryogenic chamber 3. The corrugated bellows 22 is stronger and is subjected to less mechanical stress when the pressure on its outside is equal to or greater than the pressure on its inside. The walls of the corrugated bellows 22 are therefore thinner than in the embodiment in Figs. 1 and 2, and can be, for example, between 0.05 and 0.08 mm. The corrugated bellows 22 is therefore more flexible, which facilitates its expansion and contraction and, consequently, the translation of the transmission bar 10.

[0087] Other variations and modifications can be envisioned without departing from the scope of the invention.

[0088] In particular, the device 1 may include a plurality of sheaths 6, an equal number of openings 19, and, for each sheath 6 and opening 19, a transmission bar and an adjustment rod connected to each other for translating elements contained in the cryogenic chamber 3. For example, if the device 1 is a probe for NMR spectroscopy, the device 1 may include six adjustment rods each configured to adjust one of the tuning capacitors 27 of the probe, and a seventh adjustment rod configured to adjust the tilt angle θ of a stator 29 of the probe.

[0089] References 1 Yoh Matsuki and Toshimichi Fujiwara, "Cryogenic Platforms and Optimized DNP sensitivity", eMagRes, 2018, Vol 7: 9- 24. [Explanation of symbols]

[0090] 1 device 2. Sealed enclosure 3. Cryogenic chamber 4 Internal environment 5. Insulation support 6 Sheath 7 External environment 8 grand 9 Guide sleeve 10 Transmission Bar 11 Clamping ring 12 Seals 13 Hollow cylindrical structure 14 Annular Chamber 15-pin 16 thumbwheels, thumb screws 17 Nut 18 ball bearings 19 Aperture 20 Guide tube 21 Annular seal 22 Corrugated bellows 23 Duct 24 Cable 25 Adjustment rod 26 Return spring 27 Tuning capacitor 28 Core, flange 29 Stator 30 rotors 31 Coil 32 Electrical Lead 33 Horizontal axis 34 Reduction gear

Claims

1. a sealed housing (2) comprising at least one sheath (6) emerging on an exterior (7) of said sealed housing; a cryogenic chamber (3) disposed in the sealed enclosure and including at least one opening (19) emerging in the sealed enclosure; at least one adjustment rod (25) translatably mounted within the cryogenic chamber for adjusting the position of an element contained within the cryogenic chamber; at least one transmission bar (10) sealingly passing through the sheath, the transmission bar being translatably movable along the longitudinal axis of the sheath by an element arranged outside the sheath, the transmission bar being connected to the adjustment rod so that translation of the transmission bar is transmitted to the rod and vice versa; at least one corrugated bellows (22) sealingly secured to the transfer bar around the opening to seal the cryogenic chamber; An apparatus (1) comprising:

2. 2. The apparatus of claim 1, wherein the sheath includes a gland configured to allow the transfer bar to translate while being sealed and compressed over the transfer bar.

3. The gland comprises at least one, preferably at least two seals (12) and a clamping ring (11), the clamping ring is configured to compress the seal on the transfer bar; The gland preferably includes an annular chamber (14) in which the seal is at least partially housed, the annular chamber having a diameter of 1.10 mm. －３ 3. The apparatus of claim 2, wherein the pressure is less than or equal to 1000 psi.

4. 4. The device according to claim 1, wherein the sheath comprises a guide sleeve (9) configured to guide the translation of the transfer bar and at least one immobilization means for preventing rotation of the transfer bar.

5. a thumbwheel (16) accessible from outside the sheath and a translation mechanism configured to translate rotation of the thumbwheel into translation of the transmission bar along the axis of the sheath, the transmission bar preferably including a threaded portion, the translation mechanism including a nut (17) or a gear to form, together with the threaded portion, a jackscrew or a rack and pinion system, respectively; 5. The device of any one of claims 1 to 4, wherein the device preferably includes a ball bearing (18) configured to facilitate rotation of the thumbwheel.

6. 6. The device according to claim 1, wherein the corrugated bellows is made of metal.

7. 7. The device of claim 1, wherein the corrugated bellows is hermetically welded to the transmission bar.

8. 8. The device according to any one of claims 1 to 7, comprising an annular seal (21) sealing the fixation of the corrugated bellows around the opening.

9. a transmission cable (24) having one end fixed to the transmission bar and the other end fixed to the adjustment rod; 9. The device according to any one of claims 1 to 8, wherein the device preferably comprises a guide tube (20) configured to guide the sliding of the transmission cable, the guide tube preferably extending along a curve, preferably in the shape of an S.

10. 10. The apparatus of claim 9, further comprising a return spring (26) mounted around and secured to the adjustment rod for translating the adjustment rod toward the inside of the cryogenic chamber when the cable is slackened by translation of the transmission bar toward the inside of the cryogenic chamber.

11. 11. The apparatus according to claim 1, further comprising at least one tuning capacitor (27) arranged in the cryogenic chamber, the tuning capacitor including a core (28) that can be translated to vary the tuning capacitor, and an end of the adjusting rod opposite to the end connected to the transmission bar is connected to the core and is preferably fixed.

12. 12. The apparatus according to any one of claims 1 to 11, comprising a stator (29) arranged in the cryogenic chamber and mounted rotatably about a horizontal axis (33), the adjusting rod being connected to the stator, preferably fixed, such that translation of the adjusting rod causes rotation of the stator about the horizontal axis.

13. The sealed enclosure comprises: －５ 13. The apparatus according to claim 1, wherein the pressure is less than 1000 psi.

14. 14. Apparatus according to any one of claims 1 to 13, wherein the cryogenic chamber is at a pressure of 1000 mbar to 4000 mbar and / or a temperature below 30 K.

15. 15. Apparatus according to any one of claims 1 to 14, forming a probe for a nuclear magnetic resonance (NMR) spectrometer, said probe preferably comprising a stator and at least one adjusting rod, the translation of which changes the tilt of the stator, and / or at least one adjusting rod, the translation of which changes a tuning capacitor of the probe.

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