Double-confinement heated sample holder, method for analyzing a sample using said sample holder.

Abstract

A double-confinement heated sample holder and a method for analyzing a sample using said sample holder. The invention relates to a sample holder (1) for analysis by X-ray scattering and / or X-ray spectroscopy, comprising: - an internal cell (3) including a cavity, configured to hermetically contain a sample to be analyzed, and windows opposite each other on either side of the cavity, each window being closed by a pane of glass transparent at least to X-rays; - a housing including at least one compartment, referred to as the first compartment (7), configured to hermetically contain the internal cell, and windows opposite each other on either side of the first compartment, each window being closed by a sheet transparent at least to X-rays; - at least one heating element (5) inserted in the housing so as to heat the cavity of the internal cell. Figure for the abstract: Fig. 3

Description

Title of the invention: Double-confinement heated sample holder, method for analyzing a sample using said sample holder. technical field

[0001] The present invention relates to the field of sample holders for the study of samples, preferably radioactive, by X-ray scattering and / or by X-ray spectroscopy. In particular, the present invention aims to provide a sealed sample holder suitable for studying, by X-ray scattering and / or X-ray spectroscopy, the behavior of a solid or liquid sample during a temperature change and / or during a chemical reaction caused by a temperature change, the sample being able to be radioactive, toxic and / or sensitive to air and / or humidity. Prior art

[0002] X-ray scattering and X-ray spectroscopy are known analytical techniques for analyzing a sample.

[0003] X-ray scattering is based on the scattering of radiation in the X-ray range caused by the interaction of said radiation with the electrons of the atoms of the sample to be analyzed. Among the known methods of X-ray scattering, we can mention small-angle X-ray scattering, large-angle X-ray scattering, and X-ray reflectometry.

[0004] X-ray spectroscopy can be performed by X-ray absorption, by X-ray emission or by X-ray fluorescence. X-ray absorption spectroscopy includes methods such as X-ray Absorption Near Edge Structure (XANES) spectroscopy and X-ray absorption fine structure spectroscopy.

[0005] X-ray scattering and X-ray spectroscopy can be performed in a conventional laboratory or on a synchrotron beamline. For this to be done, it is essential that the sample to be analyzed does not contaminate the characterization benches of the laboratory or the synchrotron beamline, particularly when handling radioactive and / or toxic samples. Specifically, it is common practice to handle a radioactive sample by placing it in a sealed, double-confinement sample holder suitable for characterization, for example, by X-ray scattering and / or X-ray spectroscopy. Articles [1] and [2] describe such sample holders.

[0006] Because of this constraint of placing the radioactive sample in a sample holder, X-ray scattering and / or X-ray spectroscopy measurements are generally carried out at room temperature and with the sample chemically stabilized.

[0007] Indeed, there is no known sample holder suitable for carrying out these measurements with temperature rises.

[0008] Furthermore, the radioactive sample, for example plutonium, is inserted into the sample holder via a glove box or fume hood to prevent contamination of the work environment. However, the time required to transport the sample from the glove box or fume hood to the characterization bench is often longer than the duration of the chemical reaction to be studied. Consequently, the chemical reaction to be studied is already complete by the time the sample reaches the characterization bench. It is therefore not possible to analyze, by X-ray scattering and / or X-ray spectroscopy, in real time a chemical reaction undergone by a radioactive sample.

[0009] In particular, X-ray absorption spectroscopy and small-angle X-ray scattering measurements performed on a radioactive sample cannot generally be carried out with heating of the sample and / or a chemical reaction undergone by the sample. It is therefore not possible, for example, to monitor the hydrolysis kinetics of plutonium(IV) in real time by X-ray absorption spectroscopy and small-angle X-ray scattering.

[0010] There is therefore a need for a suitable sample holder to contain a radioactive sample during an analysis by X-ray scattering and / or by X-ray spectroscopy, during which the sample undergoes a change in temperature or a chemical reaction caused by a change in temperature.

[0011] More generally, there is therefore a need for a suitable sample holder to contain a radioactive, toxic and / or air and / or moisture-sensitive sample during an analysis by X-ray scattering and / or X-ray spectroscopy, during which the sample undergoes a temperature change or a chemical reaction caused by a temperature change.

[0012] The aim of the invention is to meet, at least in part, this need. Description of the invention

[0013] To this end, the invention relates to a sample holder for analysis by X-ray scattering and / or X-ray spectroscopy, comprising: - an internal cell comprising a cavity, configured to contain in a hermetically sealed manner a sample to be analyzed, and windows opposite each other on either side of the cavity, each porthole being closed by a pane of glass transparent at least to X-rays; - a housing comprising at least one compartment, called the first compartment, configured to house the internal cell in a sealed manner, and windows opposite each other on either side of the first compartment, each window being closed by a sheet transparent at least for X-rays; - at least one heating element inserted into the housing so as to heat the cavity of the internal cell.

[0014] By definition, X-rays are radiation consisting of photons emitted in an energy range between 100 eV and 100 keV, i.e. wavelengths less than 10 nm.

[0015] For the purposes of the present invention, "transparent to X-rays" means that the transmittance is greater than 95% for X-rays with energy greater than 8 keV.

[0016] Preferably, the sample holder comprises at least two heating elements extending on either side at least along the first compartment.

[0017] Preferably, each heating element is a heating cartridge.

[0018] Preferably, the internal cell comprises: - a central plate hollowed out to form the cavity, the central plate being arranged between the panes of glass closing the portholes, - sealing gaskets arranged on either side of the central plate, surrounding the cavity, - clamping plates sandwiching the glass panes by crushing the seals between the glass panes and the central plate, the portholes being formed in the clamping plates.

[0019] The material of the central plate of the internal cell can be chosen so as to withstand the heating temperatures envisaged for the analysis and so as to be chemically inert with respect to the sample studied. Preferably, the central plate of the internal cell is made of a fluoropolymer, in particular polytetrafluoroethylene.

[0020] Preferably, the housing includes: - a central block hollowed out to form at least the first compartment, the central block being arranged between the sheets closing the windows, - sealing gaskets arranged on either side of the central block, surrounding the first compartment, - clamping blocks sandwiching the sheets by crushing the sealing joints between the sheets and the central block, the windows being formed in the clamping blocks.

[0021] The respective materials of the internal cell windows and the housing windows can be chosen so as to be chemically inert with respect to the sample. Preferably, the internal cell glass and / or the case windows are made of polyimide.

[0022] Preferably, the sample holder comprises a control cell including a cavity, configured to contain a control sample in a sealed manner, and windows opposite each other on either side of the cavity, each window being closed by a transparent window at least for X-rays, the housing comprising a second compartment separate from the first compartment, configured to house the control cell in a sealed manner, and windows opposite each other on either side of the second compartment, each window being closed by a transparent sheet at least for X-rays, the heating element(s) being adapted to also heat the cavity of the control cell.

[0023] Preferably, the control cell comprises: - a central plate hollowed out to form the cavity, the central plate being arranged between the panes of glass closing the portholes, - sealing gaskets arranged on either side of the central plate, surrounding the cavity, - clamping plates sandwiching the glass panes by crushing the seals between the glass panes and the central plate, the portholes being formed in the clamping plates.

[0024] Preferably, the sample holder includes a thermal sensor inserted in the control cell so as to measure the temperature of the cavity of the control cell, preferably the thermal sensor being a thermocouple.

[0025] Preferably, the sample holder includes a thermal sensor integrated into the housing so as to measure the temperature of the first compartment, preferably said thermal sensor being a thermocouple.

[0026] Preferably, each heating element is coupled with a thermal sensor measuring the temperature of said heating element, preferably each thermal sensor being a thermocouple.

[0027] Preferably, the sample holder includes a control unit configured to control the heating elements according to the temperature measured by the thermal sensor(s).

[0028] According to another aspect of it, the present invention also relates to a method for analyzing a sample to be analyzed, which is radioactive, toxic and / or sensitive to air and / or humidity, the method comprising the following successive steps: a) providing a sample holder according to the present invention, the sample to be analyzed being contained in a sealed manner in the cavity of the internal cell housed in the first compartment of the casing, b) observation of the sample to be analyzed by X-ray scattering and / or by X-ray spectroscopy, preferably by small-angle X-ray scattering and / or by X-ray absorption spectroscopy.

[0029] Preferably, the sample to be analyzed is radioactive.

[0030] Preferably, during step b), the sample to be analyzed undergoes a temperature change induced by heating the heating element(s) and / or a chemical reaction triggered by heating the heating element(s).

[0031] The present invention essentially consists of a sample holder adapted to contain a solid or liquid sample in a double, airtight containment, the sample holder incorporating at least one heating element within it to heat the sample. The sample holder allows the undisturbed transmission and reception of X-rays to the sample contained within the double containment.

[0032] The sample holder according to the present invention thus allows the analysis, by X-ray scattering and / or X-ray spectroscopy, of a radioactive, toxic, and / or air- and / or humidity-sensitive sample. The sample can be heated during said analysis by the sample holder itself, which ensures faster and more homogeneous heating of the sample. Furthermore, since the heating is carried out directly within the sample holder, this facilitates its control and monitoring, particularly when the sample holder includes at least one thermal sensor integrated into the housing. In addition, the sample can undergo, during said analysis, a chemical reaction triggered by the heating of the sample holder; for example, the chemical reaction can be temperature-dependent and / or a heat-sensitive compound can be contained in the cavity of the internal cell and activated and / or degradable above a predetermined temperature.

[0033] Thus, the sample holder according to the present invention is suitable for studying the behavior of a solid or liquid sample during a temperature change. It is also suitable for studying exchange and / or reaction kinetics, particularly temperature-dependent kinetics, between the sample and another compound, particularly a liquid, during a chemical reaction, for example during the extraction of metals from a liquid phase to an organic phase or vice versa.

[0034] Advantageously, the sample holder allows these various in-situ studies to be carried out both in a conventional laboratory and on a synchrotron beamline. Indeed, the double containment of the radioactive, toxic, and / or air- and / or moisture-sensitive sample allows the sample holder containing said sample to be moved safely between a conventional laboratory and a synchrotron beamline for sample analysis on standard, uncontaminated characterization benches. The double containment of the sample ensures that the sample holder according to the present invention complies with the requirements of the ASN and nuclear safety authorities. Standardized regulations in Europe ensure the absence of contamination during the movement of the sample carrier containing the sample and during its positioning at the analysis site.

[0035] Furthermore, glass panes and windows can also be transparent to ultraviolet, visible and / or infrared radiation. Thus, the sample holder according to the present invention is also suitable for other analytical methods such as ultraviolet, visible and / or infrared absorption spectroscopy, Raman spectroscopy, or dynamic light scattering. Brief description of the drawings

[0036] Other advantages and features will become clearer upon reading the detailed description, given by way of illustration and not limitation, with reference to the following figures:

[0037] [Fig.1A], [Fig.1B] and [Fig.1C] Figures IA, IB and IC are respectively perspective, side and front views of a sample holder according to the present invention;

[0038] [Fig.2] [Fig.2] is an exploded perspective view showing the different elements of a sample holder according to the present invention;

[0039] [Fig. 3] [Fig. 3] is a front view of a sample holder according to the present invention, the sample holder housing being shown in transparency;

[0040] [Fig.4A], [Fig.4B], [Fig.4C] and [Fig.4D] Figures 4A, 4B, 4C and 4D are respectively perspective, front and rear views and top views of a central block of a sample holder according to the present invention;

[0041] [Fig.5A], [Fig.5B], [Fig.5C] and [Fig.5D] Figures 5A, 5B, 5C and 5D are respectively perspective, front, side and top views of a clamping block of a sample holder according to the present invention;

[0042] [Fig.ôA] and [Fig.ôB] Figures 6A and 6B are respectively front and side views of an internal cell of a sample holder according to the present invention;

[0043] [Fig.7] [Fig.7] is an exploded perspective view showing the different elements of an internal cell of a sample holder according to the present invention;

[0044] [Fig.8A] and [Fig.8B] Figures 8A and 8B are respectively perspective and front views of a central plate of an internal cell of a sample holder according to the present invention;

[0045] [Fig.9A] and [Fig.9B] Figures 9A and 9B are respectively perspective and front views of a front clamping plate of an internal cell of a sample holder according to the present invention;

[0046] [Fig.1OA] and [Fig.1OB] Figures 10A and 10B are respectively perspective and front views of a rear clamping plate of an internal cell of a sample holder according to the present invention;

[0047] [Fig. 11 A] and [Fig. 1 IB] Figures 11A and 1 IB are respectively front views and on the side of a control cell of a sample holder according to the present invention;

[0048] [Fig. 12] [Fig. 12] is an exploded perspective view showing the different elements of a control cell of a sample holder according to the present invention;

[0049] [Fig.13A] and [Fig.13B] Figures 13A and 13B are respectively perspective and front views of a central plate of a control cell of a sample holder according to the present invention;

[0050] [Fig. 14] [Fig. 14] is a graph representing the evolution of the temperature of a sample holder according to the present invention over time for different power levels of use of the heating elements;

[0051] [Fig. 15] [Fig. 15] is a graph representing the changes over time temperatures of the heating elements and of the cavity of the control cell of a sample holder according to the present invention, during controlled heating of the sample holder. Detailed description

[0052] Figures IA to 3 illustrate a sample holder 1 according to the present invention. The sample holder 1 comprises a housing 2, an internal cell 3, a control cell 4, and heating elements 5. The internal cell 3 and the control cell 4 are housed in a sealed manner within the housing 2. The heating elements 5 are inserted into the housing 2.

[0053] The internal cell 3 contains, in a sealed manner, a sample to be analyzed. The sample to be analyzed may be radioactive, toxic, and / or sensitive to air and / or moisture. Preferably, the sample to be analyzed is radioactive. The sample to be analyzed may be liquid or solid, for example, in the form of a powder or a pellet. Preferably, the sample to be analyzed is liquid.

[0054] The control cell 4 contains a control sample in a sealed manner. The control sample is made of a material similar to the sample to be analyzed, except that it is neither radioactive nor toxic. The control sample may be liquid or solid, for example in the form of a powder or a pellet. Preferably, the control sample is a liquid. The control sample may also be a gas such as air.

[0055] The housing 2 includes a central block 6 comprising a first compartment 7 in which the internal cell 3 is housed and a second compartment 8 in which the control cell 4 is housed.

[0056] Figures 4A to 4C illustrate a central block 6. The central block 6 is metallic, for example, brass, stainless steel, or copper. The central block 6 is rectangular in shape. The central block 6 may have a width between 5 and 10 cm, for example, 7.2 cm, and / or a height between 7 and 15 cm for example equals 9.9 cm, and / or a thickness between 1 and 3 cm for example equals 1.2 cm.

[0057] The first compartment 7 is hollowed out in one of the faces of the central block 6, called the insertion face 9, so that the internal cell 3 can be inserted into the first compartment 7 on the side of the insertion face 9. Preferably, the first compartment 7 has a shape complementary to the internal cell 3. The central block 6 includes a recess 10a hollowed out in the insertion face 9 surrounding the first compartment 7 and in which a sealing gasket 1la is housed.

[0058] The central block 6 also includes a first skylight 12 cut into the face of the central block 6 opposite the insertion face 9, the first window 12 communicating with the first compartment 7. A recess 10b is cut around the first skylight 12, a sealing gasket 1 lb being housed in said recess 10b.

[0059] The second compartment 8 is cut into the insertion face 9 so that the test cell 4 can be inserted into the second compartment 8 on the side of the insertion face 9. The central block 6 includes a recess 10c cut into the insertion face 9 surrounding the second compartment 8 and in which a sealing gasket 1lc is housed.

[0060] The central block 6 also includes a second skylight 13 cut into the face of the central block 6 opposite the insertion face 9, the second skylight 13 communicating with the second compartment 8. A recess 10d is cut around the second skylight 13, a sealing gasket 1d being housed in said recess 10d.

[0061] The sealing rings 1 la d housed in the recesses 10a d of the central block 6 are fluoroelastomer O-rings, preferably in copolymer of fluorovinilidene and exafluoropropylene, also known as Viton®.

[0062] The central block 6 includes a recess 14 formed in the thickness of the central block 6 opening into the second compartment 8. A thermal sensor 15, in particular a type T thermocouple, is inserted through the recess 14 in order to measure the temperature of the control sample contained in the control cell 4.

[0063] The second compartment 8 has a height greater than the height of the control cell 4. Thus, the second compartment 8 can also accommodate a flat sealing gasket 16 and a clamping blade 17. The control cell 4 is sandwiched between the flat sealing gasket 16 and the clamping blade 17, with the flat sealing gasket 16 positioned on the side of the recess 14. The flat sealing gasket 16 is made of a fluoroelastomer, preferably a copolymer of fluorovinilidene and exafluoropropylene, also known as Viton®. Preferably, the second compartment 8 has a width and depth that are complementary to the control cell 4.

[0064] The central block 6 includes openings 18 leading into the second compartment 8. The openings 18 are drilled into the thickness of the central block 6 on either side of the recess 14. Clamping screws 19 are inserted into the openings 18, pass through the flat sealing gasket 16 and the indicator cell 4, and are screwed into the clamping blade 17 in order to compress the flat sealing gasket 16 between the indicator cell 4 and the central block 6. Thus, the flat sealing gasket 16 ensures the sealing of the insertion of the thermal sensor 15 into the second compartment 8.

[0065] The housing 2 comprises two polymer sheets 21 sandwiching the central block 6, which houses the internal cell 3 and the control cell 4. The sheets 21 are X-ray transparent. Preferably, the sheets 21 are made of polyimide, in particular Kapton®. One of the sheets 21 hermetically seals the first 7 and second 8 compartments by covering the insertion face 9 and compressing the sealing gaskets 1la and 1lc arranged around the first 7 and second 8 compartments. The other sheet 21 hermetically seals the first 12 and second 13 windows by covering the face of the central block 6 opposite the insertion face 9 and compressing the sealing gaskets 1lb and 1ld arranged around the first 12 and second 13 windows.

[0066] The housing 2 also includes two clamping blocks 22 sandwiching the sheets 21 and the central block 6 housing the internal cell 3 and the control cell 4.

[0067] Figures 5A to 5D illustrate a clamping block 22. The clamping blocks 22 are metallic, for example, stainless steel. Each clamping block 22 has the shape of a rectangular parallelepiped. Each clamping block 22 may have a width between 5 and 10 cm, for example 7.2 cm, and / or a height between 7 and 15 cm, for example 9.45 cm, and / or a thickness between 0.3 and 1.0 cm, for example 0.5 cm.

[0068] Each clamping block 22 includes two windows 23. The windows 23 of one of the clamping blocks 22 are opposite the first 7 and second 8 compartments while the windows 23 of the other clamping blocks 22 are opposite the first 12 and second 13 skylights.

[0069] Each of the clamping blocks 22, the sheets 21, and the central block 6 has a plurality of clamping holes 24. The housing 2 includes clamping rods extending through the clamping holes 24 to bring the clamping blocks 22 closer together so that they compress the sheets 21 against the central block 6. Thus, the clamping blocks 22 and the clamping rods ensure the retention and sealing of the housing 2 by ensuring sufficient compression of the sealing gaskets 1 and 2 by the sheets 21. The clamping rods may be threaded, and the clamping holes 24 of the clamping blocks 22 can be tapped, the clamping of the clamping blocks 22 then being carried out by screwing the clamping rods into the clamping holes 24.

[0070] The central block 6 includes two blind holes 25 in which the heating elements 5 are housed. The blind holes 25 are drilled through the thickness of the central block 6 and extend along the first 7 and second 8 compartments. Thus, the heating elements 25 are brought as close as possible to the internal cell 3 and the control cell 4 without breaking the seal of the first 7 and second 8 compartments. Furthermore, the heating elements 25 extend on both sides of the first 7 and second 8 compartments, which ensures homogeneous heating of the internal cell 3 and the control cell 4.

[0071] Preferably, the heating elements 5 are heating cartridges, for example, heating cartridges of the brand "Application Chauffage Industrie". Preferably, the heating cartridges can operate at up to a power of 50 W with a voltage of 230 V.

[0072] Preferably, each heating element 5 includes an integrated thermal sensor, in particular a thermocouple, for measuring the temperature of said heating element 5.

[0073] Another thermal sensor, in particular a thermocouple, can also be integrated into the central block 6 between the first compartment 7 and the second compartment 8 in order to measure the temperature of the first compartment 7. For example, said thermal sensor can be screwed into one of the faces of the central block 6.

[0074] Figures 6A, 6B, and 7 illustrate an internal cell 3 of a sample holder 1 according to the present invention. The internal cell 3 comprises a central plate 26 made of a chemically inert material containing the sample to be analyzed. In particular, the central plate 26 is made of a fluoropolymer, notably polytetrafluoroethylene.

[0075] Figures 8A and 8B illustrate a central plate 26. The central plate 26 has the shape of a rectangular parallelepiped. The central plate 26 may have a width between 1 and 5 cm, for example equal to 3.15 cm, and / or a height between 1 and 5 cm, for example equal to 2.2 cm, and / or a thickness between 0.2 and 1 cm, for example equal to 0.5 cm.

[0076] The central plate 26 is hollowed out in its center, forming a through cavity 27 in which the sample to be analyzed is intended to be contained. Preferably, the cavity 27 has a volume between 100 and 250 pL, for example, 200 pL. The central plate 26 includes a groove 28 cut into each of its faces through which the cavity 27 passes, surrounding the cavity 27. A sealing gasket 29 is housed in each of the grooves 28 surrounding the cavity 27. The sealing gaskets 29 are O-rings made of fluoroelastomer, preferably a copolymer of fluorovinilidene and hexafluoropropylene, also known as Viton®.

[0077] The internal cell 3 comprises two polymer panes 30 sandwiching the central plate 26. The panes 30 are transparent to X-rays. Preferably, the panes 30 are made of polyimide, in particular Kapton®. Each pane 30 covers one face of the central plate 26 by compressing one of the sealing gaskets 29 so as to hermetically seal the opening of the cavity 27 leading to said face covered by said plate 30.

[0078] The internal cell 3 also includes two clamping plates 31a and 31b sandwiching the windows 30 and the central plate 26. The clamping plates 31a and 31b are made of stainless steel.

[0079] Figures 9A and 9B illustrate one of the clamping plates, referred to as the front clamping plate 31a. The front clamping plate 31a is rectangular in shape. Preferably, the width and height of the front clamping plate 31a are respectively equal to the width and height of the central plate 26. The front clamping plate 31a may have a thickness between 0.1 and 1 cm, for example, 0.3 cm.

[0080] Figures 10A and 10B illustrate the other clamping plate, referred to as the rear clamping plate 31b. The rear clamping plate 31b is rectangular in shape. Preferably, the width and height of the rear clamping plate 31b are equal to the width and height of the central plate 26. The rear clamping plate 31b may have a thickness between 0.1 and 1 cm, for example, 0.3 cm.

[0081] Each clamping plate 31a and 31b includes a viewing window 32 opposite the cavity 27 of the central plate 26. Thus, the cavity 27 can be viewed by X-ray through the windows 23 of the clamping blocks 22 and through the viewing windows 32 of the clamping plates 31a and 31b. Preferably, each viewing window 32 is flared outwards from the cavity 27.

[0082] Each of the central plate 26, the windows 30, and the clamping plates 31a and 31b has a plurality of clamping holes 33. The internal cell 3 includes clamping rods extending through the clamping holes 33 to bring the clamping plates 31a and 31b closer together so that they compress the windows 30 against the central plate 26. Thus, the clamping plates 31a and 31b and the clamping rods ensure that the elements of the internal cell 3 are held together and that the cavity 27 of the central plate 26 is sealed by ensuring sufficient compression of the sealing gaskets 29 by the windows 30. The clamping rods may be threaded, and the clamping holes 33 of the rear clamping plate 31b may be tapped, the clamping of the clamping plates 31a and 31b then being achieved by screwing in the rods. tightening in the clamping holes 33.

[0083] The central plate 26 includes a channel 34 drilled through the thickness of the central plate 26 and opening into the cavity 27. The channel 34 is adapted for filling the cavity 27 with the sample to be analyzed in liquid form. This filling can be carried out using a syringe and needle inserted into the channel 34, which then inject the sample to be analyzed into the cavity 27. Once the cavity 27 is filled with the sample to be analyzed, the channel 34 is hermetically sealed. In particular, the channel 34 can be tapped, and the sealing of the channel 34 includes screwing a screw coated with adhesive, for example, epoxy, into the channel 34.

[0084] Figures 11A, 11B, and 11B illustrate a test cell 4 of a sample holder 1 according to the present invention. The test cell 4 is similar to the internal cell 3. In particular, the test cell 4 comprises a central plate 35, two sealing gaskets 36, two windows 37, a front clamping plate 38a, and a rear clamping plate 38b.

[0085] The sealing gaskets 36, the windows 37, the front clamping plate 38a and the rear clamping plate 38b included by the witness cell 4 are identical, respectively, to the sealing gaskets 29, the windows 30, the front clamping plate 31a and the rear clamping plate 31b included by the internal cell 3.

[0086] Figures 13A and 13B illustrate a central plate 35 of the control cell 4. The central plate 35 of the control cell 4 is similar to the central plate 26 of the inner cell 3. In particular, the central plate 35 of the control cell 4 is made of a fluoropolymer, notably polytetrafluoroethylene, and has the same shape and dimensions as the central plate 26 of the inner cell 3. The central plate 35 of the control cell 4 is hollowed out in its center, forming a through cavity 39 in which the control sample is intended to be contained. Preferably, the cavity 39 has a volume between 100 and 250 pL. The central plate 35 includes a groove 40 cut into each of its faces through which the cavity 39 passes, surrounding the cavity 39. Each groove 40 houses one of the sealing gaskets 36.

[0087] The central plate 35 of the control cell 4 differs from the central plate 26 of the control cell 3 in that it does not include a channel like the channel 34 of the control cell 3, but a housing 4L. The housing 41 is hollowed out in the thickness of the central plate 35 and opens into the cavity 39. The housing 41 is adapted to accommodate the thermal sensor 15 inserted through the recess 14 of the central block 6 in order to measure the temperature of the control sample contained in the cavity 39.

[0088] The housing 41 is also adapted for filling the cavity 39 with the control sample in liquid form. This filling can be carried out using a syringe and needle which are inserted into the housing 41 and then inject the control sample into the cavity 39. Once the cavity 39 is filled with the sample As a witness, the housing 41 is sealed by inserting the thermal sensor 15 into the housing 41 and then compressing the flat sealing gasket 16 as explained previously. In particular, the central plate 35 also includes through holes 42 drilled through its thickness on either side of the housing 41 and the cavity 39. The clamping screws 19 pass through the witness cell 4 via the through holes 42 to screw into the clamping blade 17 in order to compress the flat sealing gasket 16 between the witness cell 4 and the central block 6.

[0089] Furthermore, the sample holder 1 according to the present invention may include a control unit configured to control the heating elements 5 according to the temperatures measured by the thermal sensors of the sample holder 1. For example, the control unit may be a nanodac™ recorder / regulator from the brand “Eurotherm ®”.

[0090] The control unit can be configured to cut off the power supply to the heating elements 5 when the temperature measured for the heating elements 5 exceeds a first predefined temperature, and / or, when the temperature measured for the first compartment 7 and / or the cavity 39 of the control cell 4 exceeds a second predefined temperature.

[0091] The control unit may include a PID controller, for Proportional Integral Derivative. Thus, the temperature control unit makes it possible to adjust the temperature of the sample holder 1, heated by the heating elements 5, as close as possible to the desired temperature.

[0092] The following table summarizes the thermal properties of the materials used by the sample holder 1:

[0093] [Tables 1] Material Minimum operating temperature (°C) Maximum operating temperature (°C) Coefficient of thermal expansion (K⁴) Viton® -20 200 2.3 x 10⁶ Kapton® -269 400 18 x 10⁶ Polytetrafluoroethylene -200 260 16 x 10⁶

[0094] As can be seen from the preceding table, the sample holder 1 according to the present invention is well suited for any temperature change within the range of 25 to 90 °C. In particular, this range is sufficiently far from the minimum and maximum operating temperatures of the materials used by the holder. sample 1. Furthermore, the thermal expansions of the materials used by the sample holder 1 are negligible over this temperature range.

[0095] The inventors performed numerical simulations modeling the heat transfer during heating of the sample holder 1 by the heating elements 5 included in its housing 2. These simulations showed good homogeneity in the heating of the sample holder 1 by its heating elements 5. In particular, the inventors calculated a maximum temperature difference of 3 °C between the cavity 27 of the internal cell 3 and the housing 2 during numerical simulations of heating the sample holder 1 at temperatures ranging from 25 to 90 °C. No overheating points that could cause degradation of any of the materials of the sample holder 1 were detected during numerical simulations of heating the sample holder 1 at temperatures ranging from 25 to 90 °C.

[0096] Figure 14 illustrates a graph showing the temperature evolution over time of the sample holder 1 obtained during various numerical simulations modeling heat transfer during heating of the sample holder 1 by the heating elements 5 included in its housing 2. Curve 43 shows the case where the heating elements 5 each operate with a power of 0.5 W. Curve 44 shows the case where the heating elements 5 each operate with a power of 1.0 W. Curve 45 shows the case where the heating elements 5 each operate with a power of 2.0 W. Curve 46 shows the case where the heating elements 5 each operate with a power of 3.0 W. Curve 47 shows the case where the heating elements 5 each operate with a power of 4.0 W. Curve 48 shows the case where the heating elements 5 each operate with a power of 5.0 W.Curve 49 is shown when all 5 heating elements are operating at 10 W each. Curve 50 is shown when all 5 heating elements are operating at 15 W each.

[0097] As can be seen from [Fig. 14], it is possible to reach a temperature of the sample holder 1 above 80 °C in less than 10 min by supplying each of the heating elements with a power of 15 W. It is also possible to maintain a stable temperature of the sample holder 1 over time.

[0098] The inventors also tested the sample holder 1 according to the present invention by heating it with its heating elements 5 to maintain it at a temperature of 80 °C for 2 hours. For this purpose, the sample holder 1 was kept at room temperature for 10 minutes and then heated for 10 minutes to reach 80 °C. The 80 °C plateau was maintained for 2 hours by the control of the heating elements 5 by the control unit of the sample holder 1. In particular, the control unit was configured to cut off the power supply to the heating elements 5 when the measured temperature of the heating elements 5 exceeds 100 °C, or, when the temperature measured for cavity 39 of the control cell 4 exceeds 90 °C. The heating elements 5 were also controlled by the PID controller. Figure 15 illustrates curve 51, representing the evolution of the temperature measured for cavity 39 of the control cell 4 during this heating process, and curve 52, representing the evolution of the temperature measured for the heating elements 5 during this heating process.

[0099] Furthermore, the inventors have succeeded in implementing the sample holder 1 according to the present invention on a synchrotron beamline for an analytical method, using small-angle X-ray scattering and X-ray absorption spectroscopy, in order to monitor the kinetics of plutonium(IV) hydrolysis in real time. To this end, the inventors placed a stabilized chemical precursor of plutonium as the sample to be analyzed in the cavity 27 of the internal cell 3 of the sample holder 1. Then, during the step of observing the sample to be analyzed by small-angle X-ray scattering and X-ray absorption spectroscopy, the heating elements 5 raised the temperature of the sample to be analyzed so as to trigger the plutonium(IV) hydrolysis reaction at the desired time. The inventors were thus able to follow in real time the different stages of the kinetics of plutonium(IV) hydrolysis, from beginning to end.

[0100] Other variants and improvements may be envisaged without departing from the scope of the invention as defined by the following claims. List of cited references

[0101] [1] RC Belin et al. : “New hermetic sample holder for radioactive mate riais fitting to Siemens D5000 and bruker D8 X-ray diffractometers: application to the Rietveld analysis of plutonium dioxide”, J. Appl. Cryst., 2004, 37, 1034-1037.

[0102] [2] I. Llorens et al. : “X-ray absorption spectroscopy investigations on radioactive matter using MARS beamline at SOLEIL synchrotron”, Radiochim. Acta, 2014, 102 (11), 957-972.

Claims

Demands

1. Sample holder (1) for analysis by X-ray scattering and / or X-ray spectroscopy, comprising: - an internal cell (3) including a cavity (27), configured to contain in a sealed manner a sample to be analyzed, and windows (32) opposite each other on either side of the cavity, each window being closed by a glass (30) transparent at least for X-rays; - a housing (2) including at least one compartment, referred to as the first compartment (7), configured to house in a sealed manner the internal cell, and windows (23) opposite each other on either side of the first compartment, each window being closed by a sheet (21) transparent at least for X-rays; - at least one heating element (5) inserted in the housing so as to heat the cavity of the internal cell.

2. Sample holder according to the preceding claim, comprising at least two heating elements extending on either side at least along the first compartment.

3. Sample holder according to any one of the preceding claims, each heating element being a heating cartridge.

4. Sample holder according to any one of the preceding claims, the internal cell comprising: - a central plate (26) hollowed out to form the cavity (27), the central plate being arranged between the panes (30) closing the portholes (32), - sealing gaskets (29) arranged on either side of the central plate surrounding the cavity, - clamping plates (31a, 3 lb) sandwiching the panes by crushing the sealing gaskets between the panes and the central plate, the portholes being formed in the clamping plates.

5. Sample holder according to the preceding claim, the central plate being made of a fluoropolymer, in particular polytetrafluoroethylene.

6. Sample holder according to any one of the preceding claims, the housing comprising: - a central block (6) hollowed out to form at least the first compartment, the central block being arranged between the sheets (21) closing the windows (23), - sealing gaskets (21) arranged on either side of the central block surrounding the first compartment, - clamping blocks (22) sandwiching the sheets by crushing the sealing gaskets between the sheets and the central block, the windows being formed in the clamping blocks.

7. Sample holder according to any one of the preceding claims, the glass of the internal cell and / or the windows of the housing being made of polyimide.

8. Sample holder according to any one of the preceding claims, comprising a control cell (4) including a cavity (39), configured to contain a control sample in a sealed manner, and windows opposite each other on either side of the cavity, each window being closed by a window (37) transparent at least for X-rays, the housing comprising a second compartment (8) separate from the first compartment, configured to house the control cell in a sealed manner, and windows (23) opposite each other on either side of the second compartment, each window being closed by a sheet (21) transparent at least for X-rays, the heating element(s) being adapted to also heat the cavity of the control cell.

9. Sample holder according to the preceding claim, the test cell comprising: - a central plate (35) hollowed out to form the cavity (39), the central plate being arranged between the panes (37) closing the portholes, - sealing gaskets (36) arranged on either side of the central plate surrounding the cavity, - clamping plates (38a, 38b) sandwiching the panes by crushing the sealing gaskets between the panes and the central plate, the portholes being formed in the clamping plates.

10. Sample holder according to claim 8 or 9, comprising a thermal sensor (15) inserted in the control cell so as to measure the temperature of the cavity of the control cell, preferably the thermal sensor being a thermocouple.

11. Sample holder according to any one of the preceding claims, comprising a thermal sensor integrated into the housing so as to measure the temperature of the first compartment, preferably said thermal sensor being a thermocouple.

12. Sample holder according to any one of the preceding claims, each heating element being coupled with a thermal sensor measuring the temperature of said heating element, preferably each thermal sensor being a thermocouple.

13. Sample holder according to any one of claims 10 to 12, comprising a control unit configured to control the heating elements as a function of the temperature measured by the thermal sensor(s).

14. Method for analyzing a sample to be analyzed, radioactive, toxic and / or sensitive to air and / or moisture, the method comprising the following successive steps: a) providing a sample holder (1) according to any one of the preceding claims, the sample to be analyzed being contained in a sealed manner in the cavity (27) of the internal cell (3) housed in the first compartment (7) of the casing (2), b) observation of the sample to be analyzed by X-ray scattering and / or by X-ray spectroscopy, preferably by small-angle X-ray scattering and / or by X-ray absorption spectroscopy.

15. Method according to the preceding claim, during step b), the sample to be analyzed undergoing a temperature change induced by heating of the heating element(s) (5) and / or a chemical reaction triggered by heating of the heating element(s) (5).

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