Device for inserting a sample-carrier rotor into an nmr probe

Abstract

The invention relates to a device for inserting a sample (E) into a sealed enclosure (1), the device comprising: - a sample carrier (10) for holding the sample; - an insertion rod (7) comprising an elongate portion (8) suitable for bearing the sample carrier (10); - a transfer airlock (14) comprising: - an outer door (20) intended to close in a watertight manner and to open onto an environment (M) outside the sealed enclosure; - an inner door (21) intended to close in a watertight manner and to open onto the inside of the sealed enclosure; - a sealed chamber (19) defined between the outer door and the inner door when they are in the sealed configuration, the sealed chamber being configured to accommodate the sample carrier inserted by the insertion rod; - a system for purifying the contained fluid medium, the sample carrier and the sample which are accommodated in the sealed chamber.

Description

[0001] Description

[0002] Title: Device for inserting a sample rotor into an NMR probe

[0003] Technical field

[0004] The present invention relates to devices for transferring an object from one fluidic medium to another, the two media having different fluids and / or temperatures and / or pressures.

[0005] Although described for a nuclear magnetic resonance (NMR) spectroscopy application, the present invention can be implemented in any application requiring the sealed transfer of an object from one fluid medium to another fluid medium, more particularly in an environment controlled in terms of pressure and / or humidity and / or particulate pollution and / or radiological level.

[0006] Prior art

[0007] Nuclear magnetic resonance (NMR) spectroscopy is a non-destructive analytical method that uses the phenomenon of nuclear magnetic resonance (NMR), particularly to resolve molecular structures. NMR occurs when unaffected spin atomic nuclei 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.

[0008] In solid NMR spectroscopy, it is usual to place the sample to be analyzed in a rotor in order to rotate it around an axis inclined at 54°44', called the magic angle, relative to the static magnetic field.

[0009] It is also known that increasing the magnetic field strength, increasing the rotor rotation frequency, and / or using the dynamic nuclear polarization (DNP) phenomenon can improve the sensitivity and resolution of NMR spectroscopy.

[0010] It has been proven that, in NMR analysis, the lower the temperature, the higher the signal-to-noise ratio and the higher the gain due to the DNP phenomenon. Thus, high-resolution NMR spectrometers generally operate at low temperatures, especially around 100 K. The article by Yoh Matsuki and Toshimichi Fujiwara, “Cryogenic Platforms and Optimized DNP sensitivity”, eMagRes, 2018, Vol 7: 9-24, describes an NMR spectrometer using the DNP phenomenon and operating at temperatures below 100 K.

[0011] To achieve low temperatures, for example around or below 100 K, it is preferable for the NMR spectrometer to operate autonomously and in a closed loop. A device operating autonomously is one that does not require a cryogenic fluid supply. A closed loop device is one in which a working fluid circulates without exposure to the external environment and without transfer of fluid out of the loop.

[0012] In such autonomous and closed-loop devices, it is important to maintain a high purity of the working fluid, i.e. that it is free as much as possible from impurities whatever their nature (gaseous, solid in the form of particles, from hydrocarbons, etc.).

[0013] For NMR spectrometers, pollution of the working fluid may be due to the placement of the sample to be analyzed in the NMR probe.

[0014] Figures 1A to 1E illustrate the different steps of placing a sample in a probe 1 of an NMR spectrometer according to the prior art.

[0015] The probe 1 comprises a bottom wall 2, a cover 3 and a stator 4.

[0016] To be able to open the probe 1, it is first necessary to heat the internal medium 5 delimited by the bottom wall 2 and the cover 3 assembled together in a sealed manner (figure 1A).

[0017] Probe 1 is then opened manually by lifting the waterproof cover 3 (figure 1B).

[0018] Then, a rotor 6 in which a sample to be analyzed is housed, is manually placed in the stator 4 (figure IC).

[0019] The cover 3 is then replaced in order to close the probe 1 tightly (figure 1D).

[0020] The internal medium 5 is then cooled, and then a set of working fluid purification cycles are applied, in order to remove the impurities brought in during the opening of the probe 1 and the insertion of the rotor 6 into the stator 4 (figure 1E). The total duration of the steps described, relating to the placement of a sample in the probe

[0021] It takes about eight hours, which is particularly time-consuming. Furthermore, the purification cycles are complex to implement.

[0022] There is therefore a need for a solution to reduce the time taken to place a sample to be analyzed in an NMR probe and to simplify the implementation of the existing process.

[0023] More generally, there is a need for a solution that allows a sample to be transferred simply and quickly from an external environment to a controlled environment while limiting the input of impurities into the latter.

[0024] The aim of the invention is to respond, at least in part, to this(these) need(s).

[0025] Statement of the invention

[0026] To do this, the invention relates to a device for inserting a sample into a hermetic enclosure, the device comprising:

[0027] - a sample holder to carry the sample;

[0028] - an insertion rod comprising an elongated portion one end of which is adapted to carry the sample holder;

[0029] - a transfer airlock comprising:

[0030] • an exterior door, designed to close tightly and to open onto an environment outside the hermetic enclosure,

[0031] • an interior door, intended to close tightly and to open onto the interior of the hermetic enclosure directly or indirectly via at least one sealed conduit,

[0032] • a sealed chamber delimited between the outer door and the inner door when they are in a sealed closed configuration, the sealed chamber being configured to house the sample holder, inserted by the insertion rod;

[0033] - a system for purifying the fluid medium contained and the sample holder and sample housed in the sealed chamber.

[0034] The purification system according to the invention has the function of reducing the level of impurities and / or the level of radioactivity of the fluid medium contained in the sealed chamber, and therefore of the sample holder and the sample to be analyzed that it carries. By "level of impurities of a fluid medium", is meant here and in the context of the present invention, the ratio, generally expressed in ppm (part / million), of the mass fraction of the impurities contained in the fluid medium to the total mass of said fluid medium.

[0035] Radioactive elements and / or impurities are any gaseous, liquid, or solid elements in particulate form that are not desired in the target fluid medium, i.e., that do not correspond to the level of purity and / or the level of radioactivity of the fluid that is desired to fill a sealed enclosure. For example, the level of impurities may be less than or equal to 100 ppm.

[0036] Preferably, the outer door includes a gland configured to be tightly compressed by the elongated portion of the insertion rod while leaving it translationally movable.

[0037] Preferably, the purification system comprises:

[0038] - a discharge valve, configured to discharge the fluid contained in the chamber up to a nominal pressure, called low pressure,

[0039] - a filling valve, configured to fill the chamber with a predetermined fluid, intended to fill the sealed enclosure, up to another nominal pressure, called high pressure.

[0040] Preferably, the low pressure is less than or equal to 10 mbar and / or the high pressure is greater than or equal to 1 bar, or even 1.1 bar, preferably between 1 and 3 bar.

[0041] Preferably, the fill valve is configured to passively close when the chamber pressure reaches the high pressure.

[0042] Preferably, the predetermined fluid is a pure gas, preferably at least 99.999% pure helium.

[0043] Preferably, the elongated portion extends over a length of between 15 cm and 30 cm.

[0044] Preferably, the elongated portion is cylindrical in shape, preferably with a diameter of between 0.3 cm and 1.0 cm.

[0045] Preferably, the end of the elongated portion, opposite that carrying the sample holder, comprises a gripping handle. Preferably, the gripping handle has a diameter greater than the opening diameter of the outer door, for example greater than or equal to 10 mm. Preferably, the sample holder comprises a cavity into which the sample is intended to be inserted. Preferably, the cavity is cylindrical in shape, preferably with a diameter of between 0.8 mm and 3.3 mm and / or a height of between 12 mm and 20 mm, for example 18 mm.

[0046] Preferably, the sample holder comprises a lumen opening into the cavity and configured to allow the injection of a fluid into the cavity so as to propel the sample out of the cavity.

[0047] Preferably, the inner door is a slide valve configured to slide between a closed position, in which the inner door is sealed, and an open position, in which the inner door is open to allow passage of the sample holder and the elongated portion of the insertion rod.

[0048] Preferably, the interior door is configured so as to maintain its seal for a pressure less than or equal to 1.10' 5 mbar.

[0049] Preferably, the stuffing box comprises at least one, preferably at least two, sealing gasket(s), clamping rings and a screw, the clamping rings being configured to crush the sealing gasket(s), when the screw is screwed in, so that the sealing gasket(s) compress the elongated portion which ensures the sealing of the closure of the exterior door.

[0050] Preferably, the screw is hollow and has an inner diameter greater than the diameter of the sample holder and the elongated portion.

[0051] Preferably, the stuffing box comprises an annular chamber in which the sealing gasket(s) is / are partly housed, the annular chamber being at a pressure less than or equal to 1.10' 3 mbar.

[0052] Preferably, the chamber has a volume of between 3000 mm 3 and 7000 mm 3 .

[0053] Preferably the chamber is tubular in shape with the inner door at one end of the tube and the outer door at the other end of the tube.

[0054] Preferably, the distance between the outer door and the inner door is between 0 and 20 cm. The invention also relates to a system comprising a hermetic enclosure and a device according to the invention, the outer door of the transfer airlock being intended to open onto the environment outside the hermetic enclosure and the inner door of the transfer airlock being intended to open directly or indirectly via a sealed conduit onto the interior of the hermetic enclosure.

[0055] Preferably, the system is a nuclear magnetic resonance (NMR) spectrometer and the sealed enclosure is a probe configured to excite atomic nuclei of a sample. Preferably, the probe is configured to implement the phenomenon of dynamic nuclear polarization.

[0056] Preferably, the internal medium of the probe is composed of a fluid in which the sample is intended to bathe, the probe being configured to maintain said fluid at a temperature below 100 K, preferably said fluid being at least 99.999% pure helium.

[0057] Preferably, the system comprises a rotor on which the sample is intended to be mounted and configured to be carried by the sample holder, the probe comprising a stator configured to rotate the rotor.

[0058] Preferably, the probe comprises a pneumatic tube connecting the transfer airlock to the stator and being configured to move by propulsion the rotor of the sample holder, when inserted into the probe, into the stator and vice versa.

[0059] The invention also relates to a method of operating a system according to the invention, comprising the following successive steps: a) placing a sample on the sample holder of the insertion rod, b) inserting the sample holder and the sample into the chamber of the transfer airlock through the outer door, the inner door being tightly closed, c) tightening the stuffing box to compress the elongated portion so as to tightly close the outer door, d) purifying, by the purification system, the fluid contained in the chamber, e) opening the inner door and inserting the sample holder and the sample into the hermetic enclosure through the inner door, the stuffing box being kept tight to be compressed around the elongated portion so as to keep the outer door tightly closed.For the purposes of the present invention, the term “purifying” a fluid means reducing its level of impurities.

[0060] Preferably, the purification system of the device comprises:

[0061] - a discharge valve, configured to discharge the fluid contained in the chamber up to a nominal pressure, called low pressure,

[0062] - a filling valve, configured to fill the chamber with a predetermined fluid, intended to fill the hermetic enclosure, up to another nominal pressure, called high pressure, and, step d) comprises at least one iteration of the following sub-steps: di) opening the discharge valve so as to discharge the fluid contained in the chamber, for example gas, up to a nominal pressure, called low pressure, the filling valve being closed; d2) closing the discharge valve; ds) opening the filling valve so as to fill the chamber with the fluid constituting the internal medium of the hermetic enclosure, for example helium that is at least 99.999% pure, up to another nominal pressure, called high pressure; cU) closing the filling valve.

[0063] Preferably, the low pressure is less than or equal to 10 mbar and / or the high pressure is between 1 and 3 bar.

[0064] Preferably, step d) comprises at least three iterations of substeps di) to cU).

[0065] Preferably, the system is a nuclear magnetic resonance (NMR) spectrometer and the sealed enclosure is a probe configured to excite the atomic nuclei of a sample, and, the method comprises, subsequently to step e), a step g) of nuclear magnetic resonance spectrometry of the sample.

[0066] Preferably, the probe of the system comprises a pneumatic tube connecting the transfer airlock to the stator and being configured so as to move by propulsion the rotor of the sample holder, when inserted into the probe, into the stator and vice versa, and, step g) being preceded by a step f) of placing the rotor, on which the sample is mounted, in the stator by propulsion of said rotor in the pneumatic tube.

[0067] Preferably, the method comprises a subsequent step h) during which the sample is extracted from the sealed enclosure, said step h) comprising the following successive sub-steps: hi) pulled from the insertion rod so as to place the sample holder and the sample in the chamber of the transfer airlock, the sample being supported by the sample holder, the stuffing box being kept tight to compress the elongated portion so as to keep the outer door tightly closed,

[0068] I12) watertight closure of the inner door, ha) optionally, opening of the filling valve,

[0069] I14) loosening the stuffing box so as to open the outer door sufficiently to allow the sample holder and the sample to pass through, hs) extracting the sample holder and the sample from the transfer airlock through the outer door, hô) optionally, replacing the sample holder in the chamber of the transfer airlock, the sample being removed from the sample holder, then tightening the stuffing box to compress the elongated portion so as to seal the outer door, if necessary closing the filling valve.

[0070] The present invention therefore essentially consists of a device comprising a transfer airlock and a sample holder insertion rod for easily inserting a biological sample or a sample of material to be analyzed into a hermetic enclosure, such as an NMR probe.

[0071] When the sample holder carrying the sample is housed in the transfer airlock chamber delimited by two tightly closed doors, the purification system can purify the impurities brought into the chamber by the sample holder inserted therein.

[0072] Once the impurity level and / or radioactivity level of the fluid medium contained in the chamber has reached a level low enough for the airtight enclosure, the inner door of the airlock can be opened and the sample holder with the sample can be inserted by the rod into the airtight enclosure without polluting it.

[0073] The handling for inserting the sample into the hermetic enclosure is easy: only a translation of the insertion rod is sufficient. According to an advantageous embodiment, the elongated portion of the rod is compressed by a stuffing box while leaving it movable in translation, which ensures the tight closure of the external door throughout the translational stroke of the insertion rod.

[0074] The present invention advantageously allows the transfer of a sample from an external fluid medium to a fluid medium contained in a hermetic enclosure, the transfer being simple and rapid to implement while limiting the contribution of impurities into the fluid medium of the hermetic enclosure. In particular, the transfer of the sample can be done in a few minutes. For example, for an NMR spectrometer, the installation of a rotor, in which a sample is mounted, in a stator of the probe of the NMR spectrometer can be done in five minutes thanks to the present invention, compared to eight hours for an NMR spectrometer according to the prior art.

[0075] In addition, the purification system can also be configured to put the fluid medium contained in the sealed chamber at a given pressure. This advantageously ensures that the insertion of the sample into the sealed enclosure has little or no impact on the pressure of the fluid medium in the sealed enclosure.

[0076] Brief description of the drawings

[0077] Other advantages and characteristics will become more apparent upon reading the detailed description, given for illustrative and non-limiting purposes, with reference to the following figures:

[0078] [Fig IA] Figure IA is a schematic view of a probe according to the prior art, the cover of the probe being closed;

[0079] [Fig IB] Figure IB is a schematic view of the probe according to Figure 1A, with the probe cover open;

[0080] [Fig IC] Figure IC is a schematic view of the probe according to Figure 1A, with the probe cover open and a rotor, on which a sample is mounted, installed in the probe stator;

[0081] [Fig ID] [Fig 1E] Figures 1D and 1E are schematic views of the probe according to Figure 1A, with the probe cover closed and a rotor, on which a sample is mounted, installed in the probe stator;

[0082] [Fig 2A] Figure 2A is a side view of an insertion rod of a device according to the invention and a rotor on which a sample is mounted, the rotor not being inserted into the insertion rod. [Fig 2B] Figure 2B is a side view of an insertion rod of a device according to the invention and a rotor on which a sample is mounted, the rotor being inserted into the insertion rod.

[0083] [Fig 3] Figure 3 is a schematic longitudinal sectional view of a part of an NMR spectrometer comprising a transfer airlock of a device according to the invention connected with a probe for NMR spectrometry.

[0084] [Fig 4] Figure 4 is a schematic longitudinal sectional view of part of an NMR spectrometer comprising a device according to the invention, the transfer airlock of the device being connected with a probe for NMR spectrometry and the insertion rod of the device being partly inserted into the transfer airlock with the sample holder housed in the chamber of said airlock.

[0085] [Fig 5] Figure 5 is a schematic longitudinal sectional view of a part of an NMR spectrometer comprising a device according to the invention, the transfer airlock of the device being connected with a probe for NMR spectrometry and the sample holder of the insertion rod of the device being inserted into the probe.

[0086] [Fig 6] Figure 6 is a schematic longitudinal sectional view of part of an NMR spectrometer comprising a device according to the invention, the transfer airlock of the device being connected with a probe for NMR spectrometry, the sample holder of the insertion rod of the device being inserted into the probe and a rotor being propelled out of the sample holder.

[0087] [Fig 7A] Figure 7A is a schematic view of a probe of an NMR spectrometer connected with a transfer airlock of a device according to the invention, the probe comprising a pneumatic tube in which a rotor is propelled towards the stator of the probe.

[0088] [Fig 7B] Figure 7B is a schematic view of the probe and transfer airlock according to Figure 7A, with the rotor inserted into the stator of the probe.

[0089] Detailed description

[0090] For reasons of clarity, the various elements of the figures are represented in free scale, the actual dimensions of the different parts not necessarily being respected.

[0091] Figures 1A to 1E have already been commented on in the preamble and will not be further commented on below. Figure 2A illustrates the insertion rod part 7 of a device according to the invention, one end of which carries a rotor 6 intended to house a sample E to be analyzed.

[0092] The insertion rod 7 comprises an elongated portion 8, extending along a longitudinal axis X, one of the longitudinal ends of which is shaped into a gripping handle 9 and the other of the longitudinal ends of which can carry a sample holder 10. The elongated portion 8 may be a cylinder with a length equal to 180 mm with a diameter equal to 6 mm. The handle 9 may be cylindrical, for example with a length equal to 20 mm, and have ridges to facilitate gripping of the insertion rod 7.

[0093] The sample holder 10 comprises a cavity 11 for housing and supporting the rotor 6, and a lumen 12 opening into the cavity 11 between the longitudinal end of the elongated portion 8 and the cavity 11. The cavity 11 is of cylindrical shape with a diameter of between 0.8 and 3.3 mm, for example equal to 3.3 mm, and / or a height of between 12 and 20 mm, for example equal to 18 mm. These dimensions are suitable for low-temperature NMR spectroscopy. The cavity 11 can thus be of complementary shape with the rotor 6, which is for example a cylinder with a diameter of between 0.7 and 3.2 mm, for example equal to 3.2 mm, and / or a height of between 12 and 20 mm, for example equal to 17 mm.

[0094] The end of the elongated portion 8 and / or the sample holder 10 may support an O-ring 13 at its periphery.

[0095] In Figure 2B, the rotor 6 is housed in the cavity 11.

[0096] Figure 3 illustrates an NMR spectrometer comprising a transfer airlock 14 of a device according to the invention assembled with a probe 1 for NMR spectrometry via a sealed conduit 15.

[0097] The probe 1 is a hermetic enclosure comprising a sealed wall 2 and whose internal medium 5 is composed of helium that is at least 99.999% pure.

[0098] The probe 1 differs from that of the prior art illustrated in Figures 1 to 1D, in particular in that it comprises a pneumatic tube 16 arranged in the hermetic enclosure and a connector

[0099] 17 opening inside the pneumatic tube 16 so as to be able to inject gas, preferably helium pure at least 99.999%, into the pneumatic tube 16. A crossing

[0100] 18 sealingly connects the sealed conduit 15 with the pneumatic tube 16. The transfer airlock 14 comprises a chamber 19 delimited by an outer door 20 and an inner door 21 when they are in their sealed closed configuration. The outer door 20 can open onto an external medium M to the sealed enclosure, and the inner door 21 can open onto the sealed conduit 15. The distance between the outer door 20 and the inner door 21 is less than the length of the elongated portion 8.

[0101] In the illustrated example, the chamber 19 is of hollow cylindrical shape, preferably with a diameter less than or equal to 45 mm.

[0102] The inner door 21 is a slide valve which can be closed tightly and which can be opened sufficiently to allow the passage of the sample holder 10 and the elongated portion 8.

[0103] The outer door 20 comprises a stuffing box 25 configured to compress the elongated portion 8 in a sealed manner, while leaving the insertion rod 7 movable in translation to be inserted into the transfer airlock 14.

[0104] The stuffing box 25 comprises two clamping rings 26, two seals 27 and a hollow screw 28. The internal diameter of the hollow screw 28, smaller than the diameter of the handle 9, is sufficient to allow the passage of the sample holder 10 with the sample E and the elongated portion 8. When the hollow screw 28 is screwed, it compresses the clamping rings 26 against the seals 27 which are then crushed. The crushing of the seals 27 reduces their internal diameter which can thus be smaller than the external diameter of the elongated portion 8. Thus, the seals 27 which surround the elongated portion 8 while being crushed, come to be compressed around the elongated portion 8, which achieves the watertight closure of the external door 20.

[0105] The stuffing box 25 also includes an annular chamber 29 around the clamping rings 26 and the sealing gaskets 27. The annular chamber 29 is pumped under vacuum to a pressure, typically less than or equal to 1.10' 3 mbar. Thus, the volume between the clamping rings 26 and the sealing gaskets 27 and the volume between the two sealing gaskets 27 is at a pressure less than or equal to 1.10“ 3 mbar which ensures better crushing of the seals 27 and better sealing of the closure of the outer door. The outer door 20 also includes a clamping collar 30 compressing a seal 31 to ensure sealing between the stuffing box 25 and the interior of the chamber 19.

[0106] The chamber 19 is configured to accommodate the sample holder 10 with the elongated portion 8 compressed by the gland 25, the chamber 19 then being sealed. The chamber 19 is also configured to be traversed by the sample holder 10 through the outer door 20 and the inner door 21.

[0107] The transfer airlock 14 also comprises a discharge valve 23, configured to discharge the fluid contained in the chamber 19, and a filling valve 24, configured to fill the chamber 19 with helium that is at least 99.999% pure. Thus, the purification fluid can be the same fluid as that of the internal medium 5.

[0108] The method of inserting a sample E into the probe 1 with the device according to the invention will now be described.

[0109] First, the method comprises a step a) of placing the sample E on the insertion rod 7. During this step a), the sample E is mounted in the rotor 6, then the rotor 6 is inserted into the cavity 11 of the sample holder 10, as illustrated in FIG. 2B.

[0110] The method then comprises a step b) of inserting the rotor 6 and the sample holder 10 into the chamber 19. During this step b), the inner door 21 is sealed closed, the valves 23 and 24 are also sealed closed. The insertion is carried out by translation of the insertion rod 7 through the outer door 20, the stuffing box 25 not being tightened. After insertion, the stuffing box 25 is arranged without compression around the elongated portion 8 and the rotor 6 and the sample holder 10 are entirely housed in the chamber 19 (figure 4).

[0111] Step b) is followed by a step c) during which the stuffing box 25 is tightened so as to be compressed around the elongated portion 8 and thus tightly close the outer door 20. The chamber 19 is then hermetically closed with the rotor 6 and the sample holder 10 housed inside.

[0112] A step d) of purifying the fluid contained in the chamber 19 is then carried out. This step d) comprises at least one iteration of the following sub-steps: di) opening the discharge valve 23 so as to discharge the fluid contained in the chamber 19, for example gas, up to a nominal pressure, called low pressure, the filling valve 24 being closed; d2) closing the discharge valve 23; ds) opening the filling valve 24 so as to fill the chamber 19 with the fluid making up the internal medium 5 of the probe 1, up to another nominal pressure, called high pressure; cU) closing the filling valve 24, the closing can be done passively when the pressure inside the chamber 19 reaches the high pressure.

[0113] This purification step d) makes it possible to purify the impurities imported during the insertion of the rotor 6 and the sample holder 10 into the chamber 19 by dilution. In particular, during step b), the chamber 19 is filled with the atmosphere of the external environment M. Step d) then makes it possible to dilute the polluting gases with fluid composing the internal environment 5 sufficiently so that the level of impurities contained in the chamber 19 after purification is less than or equal to 0.00001% corresponding to 100 ppm.

[0114] Step d) may comprise at least three iterations of sub-steps di) to cU). The ratio between the volume of the chamber 19 and the volume of the sealed enclosure 1 may be less than or equal to 1 / 100000. This advantageously makes it possible to increase the dilution of the pollutants at each iteration of sub-steps di) to cU) and, consequently, to increase the speed at which the level of impurities in the fluid medium of the chamber 19 decreases. The dilution rate of the impurities at each iteration of sub-steps di) to cU), i.e. the ratio between the level of impurities after an iteration and the level of impurities before said iteration, may in particular be less than or equal to 1%, or even 0.9%.

[0115] Step d) is followed by a step e) during which the inner door 21 opens and the insertion rod 7 slides along its elongated portion 8 until the rotor 6 and the sample holder 10 are inserted into the pneumatic tube 16. The stuffing box 25 is kept tight throughout step e) so as to keep the outer door 20 tightly closed. The tightening during step e) may be less than during step d) so as to facilitate the translational movement of the insertion rod 7. In particular, during step d) the tightening of the stuffing box 25 may be such that it blocks any translation of the insertion rod 7 and thus maintains the rotor 6 and the sample holder 10 in a fixed position in the chamber 19. During step e) the stuffing box 25 may be slightly loosened so as to keep the outer door 20 closed in a sealed manner and to allow the translation of the insertion rod 7 along the longitudinal axis X.

[0116] Figure 5 illustrates the NMR spectrometer with the rotor 6 and the sample holder 10 inserted into the pneumatic tube 16 of the probe 1, by means of the rod of the device according to the invention. In this configuration, the handle 9 is in abutment against the outer door 20. The O-ring 13 is housed in the bushing 18 so as to guarantee the seal between the sealed conduit 15 and the pneumatic tube 16. The light 12 is aligned with the connector 17.

[0117] Step e) is followed by a step f) of placing the rotor 6, on which the sample E is mounted, in the stator 4 of the probe 1. Step f) is carried out in particular by propelling the rotor 6 into the pneumatic tube 16. As illustrated in FIG. 6, a fluid F, preferably 99.999% pure helium, circulates in the connector 17 into the cavity 11 via the port 12. Under the thrust of the fluid F, the rotor 6 is propelled out of the cavity 11 and guided along the pneumatic tube 16.

[0118] During guidance in the pneumatic tube 16 and in the NMR probe, the insertion rod 7 is kept inserted in the transfer airlock 14 with the outer door 20 tightly closed.

[0119] Figure 7 A illustrates the guidance, along the pneumatic tube 16, of the rotor 6 propelled by the fluid F to the stator 4 of the probe 1.

[0120] Figure 7B illustrates the rotor 6 introduced into the stator 4 of the probe 1. The sample E will then, during a step g), be observed by NMR spectrometry. During step g), the rotor 6 rotates the sample E in the stator 4 around an axis inclined at 54° relative to the magnetic field for the NMR spectrometry. The rotation speed of the sample E may be greater than one or more million revolutions per minute. The stator 4 may comprise an aerostatic bearing supplied with at least 99.999% pure helium to guide the rotor 6 in rotation. The rotation of the sample E may be carried out by a flow of at least 99.999% pure helium.

[0121] Preferably, during step g), the internal medium 5 of the probe 1 is at a pressure of between 1 and 3 bar and / or at a temperature of less than or equal to 100 K. The probe 1 may in particular work autonomously and in a closed loop, for example it may comprise heat exchangers and at least one cold source, for example cryocoolers. The internal medium 5 being composed of helium that is at least 99.999% pure, the control of the internal medium 5 at the aforementioned pressure and temperature is facilitated. The stator 4 may be supplied with helium that is at least 99.999% pure and at a temperature of less than 100 K, the flow of this cold helium makes it possible to maintain the sample E at a temperature of less than 100 K.

[0122] After the NMR spectrometry, the rotor 6 and the sample E can be extracted from the probe 1 during a step h). For this, step h) comprises a sub-step hi) during which the rotor 6, on which the sample E is mounted, will be propelled out of the stator 4 and guided along the pneumatic tube 16 until it is inserted into the cavity 11 of the sample holder 10. Then, the insertion rod 7 is pulled so as to place the sample holder 10 and the sample E in the chamber 19 of the transfer airlock 14, the outer door 20 being kept tightly closed by the elongated portion 8 and the stuffing box 25.

[0123] The sub-step hi) is followed by a sub-step I12) during which the inner door 21 is closed in a sealed manner. This is followed by a sub-step ha) of opening the filling valve 24, at least 99.999% pure helium then filling the chamber 19.

[0124] Then, the stuffing box 25 is loosened during a sub-step I14) so ​​that the outer door 20 allows the passage of the sample holder 10 and the sample E. Then, the insertion rod 7 is pulled outwards, during a sub-step hs), in order to extract the sample holder 10 and the sample E from the transfer airlock 14 through the outer door 20.

[0125] Step h) comprises a subsequent sub-step h) during which the sample E is extracted from the cavity 11 of the sample holder 10, then the sample holder 10 is replaced in the chamber 19, without the sample E. The stuffing box 25 is then tightened so as to compress the elongated portion 8 and seal the outer door 20. Then, the filling valve 24 is sealed.

[0126] Other variations and improvements may be envisaged without departing from the scope of the invention as defined by the claims below.

[0127] In particular, although described in application for NMR spectroscopy, the present invention is applicable to any system requiring the transfer of an object from one fluid medium to another fluid medium, in particular in a controlled environment.

Claims

Claims 1. Device for inserting a sample (E) into a sealed enclosure (1), the device comprising: - a sample holder (10) for carrying the sample; - an insertion rod (7) comprising an elongated portion (8) one end of which is adapted to carry the sample holder (10); - a transfer airlock (14) comprising: • an external door (20), intended to close tightly and to open onto an environment (M) outside the hermetic enclosure, • an interior door (21), intended to close in a sealed manner and to open onto the interior of the sealed enclosure directly or indirectly via at least one sealed conduit (15), • a sealed chamber (19) delimited between the outer door and the inner door when they are in a sealed closed configuration, the sealed chamber being configured to house the sample holder, inserted by the insertion rod; - a system for purifying the fluid medium contained and the sample holder and sample housed in the sealed chamber.

2. Device according to claim 1, the outer door comprising a stuffing box (25) configured to be compressed in a sealed manner by the elongated portion of the insertion rod while leaving it movable in translation.

3. Device according to claim 1 or 2, the purification system comprising: - an evacuation valve (23), configured to evacuate the fluid contained in the chamber up to a nominal pressure, called low pressure, - a filling valve (24), configured to fill the chamber with a predetermined fluid, intended to fill the sealed enclosure, up to another nominal pressure, called high pressure.

4. Device according to one of the preceding claims, the sample holder comprising a cavity (11) into which the sample is intended to be inserted.

5. Device according to claim 4, the sample holder comprising a lumen (12) opening into the cavity and configured to allow the injection of a fluid into the cavity so as to propel the sample out of the cavity.

6. Device according to one of the preceding claims, the inner door being a slide valve configured to slide between a closed position, in which the inner door is sealed, and an open position, in which the inner door is open to allow the passage of the sample holder and the elongated portion of the insertion rod.

7. Device according to one of the preceding claims, the interior door being configured so as to maintain its closure in a sealed state for a pressure less than or equal to 1.10' 5 mbar.

8. Device according to one of the preceding claims, the stuffing box comprising at least one, preferably at least two, sealing gasket(s) (27), clamping rings (26) and a screw (28), the clamping rings being configured to crush the sealing gasket(s), when the screw is screwed in, so that the sealing gasket(s) compress the elongated portion which ensures the sealing of the closure of the external door.

9. System comprising a hermetic enclosure (1) and a device according to one of the preceding claims, the outer door (20) of the transfer airlock (14) being intended to open onto the environment (M) outside the hermetic enclosure and the inner door (21) of the transfer airlock being intended to open directly or indirectly via a sealed conduit (15) onto the interior of the hermetic enclosure.

10. System according to claim 9, the system being a nuclear magnetic resonance (NMR) spectrometer and the hermetic enclosure being a probe configured to excite the atomic nuclei of a sample (E), the probe preferably being configured so as to implement the phenomenon of dynamic nuclear polarization.

11. System according to claim 10, comprising a rotor (6) on which the sample (E) is intended to be mounted and configured to be carried by the sample holder, the probe comprising a stator configured to rotate the rotor.

12. System according to claim 11, the probe comprising a pneumatic tube (16) connecting the transfer airlock to the stator and being configured so as to move by propulsion the rotor of the sample holder, when inserted into the probe, into the stator and vice versa.

13. A method of operating a system according to one of claims 9 to 12, comprising the following successive steps: a) placing a sample (E) on the sample holder (10) of the insertion rod (7), b) inserting the sample holder and the sample into the chamber (19) of the transfer airlock (14) through the outer door (20), the inner door (21) being tightly closed, c) tightening the stuffing box (25) to compress the elongated portion (8) so as to tightly close the outer door, d) purifying, by the purification system, the fluid contained in the chamber, e) opening the inner door and inserting the sample holder and the sample into the hermetic enclosure through the inner door, the stuffing box being kept tight to be compressed around the elongated portion so as to keep the outer door tightly closed.

14. Method according to claim 13, the device for inserting the sample (E) being according to claim 3 or according to one of claims 4 to 10 taken in dependence with claim 3, step d) comprising at least one iteration of the following sub-steps: di) opening the evacuation valve (23) so as to evacuate the fluid contained in the chamber (19), for example gas, up to a nominal pressure, called low pressure, the filling valve (24) being closed; d2) closing the evacuation valve (23); ds) opening the filling valve (24) so ​​as to fill the chamber with the fluid constituting the internal medium (5) of the hermetic enclosure, for example helium pure at least 99.999%, up to another nominal pressure, called high pressure; cU) closing the filling valve (24).

15. Method according to one of claims 13 and 14, the system being according to one of claims 10 to 12 and the method comprising, subsequently to step e), a step g) of nuclear magnetic resonance spectrometry of the sample (E).

16. Method according to one of claims 13 to 15, comprising a subsequent step h) during which the sample (E) is extracted from the hermetic enclosure, said step h) comprising the following successive sub-steps: hi) pulled from the insertion rod so as to place the sample holder and the sample in the chamber of the transfer airlock, the sample being supported by the sample holder, the stuffing box being kept tight to compress the elongated portion so as to keep the outer door tightly closed, I12) sealing the inner door, ha) optionally, opening the filling valve, I14) loosening the stuffing box so as to open the outer door sufficiently to allow the sample holder and the sample to pass through, hs) extracting the sample holder and the sample from the transfer airlock through the outer door, hô) optionally, replacing the sample holder in the chamber of the transfer airlock, the sample being removed from the sample holder, then tightening the stuffing box to compress the elongated portion so as to seal the outer door, if necessary closing the filling valve.

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