Inverted core temperature control system for sorption analysis

Abstract

A sample vessel assembly for performing sorption analysis in a container provided with a cooling liquid. The sample vessel assembly includes a sample vessel configured to be suspended in the container. The sample vessel has a sample holding area at the sample end of the vessel to hold the sample to be analyzed. A core is arranged on the sample vessel and surrounds the sample holding area. When the sample vessel is arranged in an analysis position in the container, the core extends from the sample holding area to extend toward the bottom of the container and draws the cooling liquid above the sample holding area.

Description

Background of the Invention

[0001] Field of the Invention

[0002] Temperature control device for adsorption analyzer.

[0003] Description of Related Technology

[0004] Adsorption analysis is used to characterize the porosity and surface area of ​​solid materials. In a typical analysis, the solid to be analyzed is cooled to cryogenic temperatures.

[0005] The present invention relates to the field of pore size determination and specific surface determination by gas sorption method. In this method, the vessel containing the sample is immersed in a Dewar flask filled with a cooling liquid at low temperature, such as liquid nitrogen, to keep the temperature inside the sample vessel low and constant during the sorption process. Any temperature change will cause pressure changes, which will lead to errors in the determination of the amount of adsorbed gas.

[0006] Although different techniques can be used to control the sample temperature, the most common practice is to introduce the sample into a glass cell and immerse the portion of the cell holding the sample in a cryogenic liquid (e.g., liquid nitrogen or liquid argon) and connect the cell to a device that dispenses a known amount of gas into the cell and follows the system pressure.

[0007] Since the volume, temperature, and pressure in the system are known, the amount of gas interacting with the sample can be calculated by using the real gas law.

[0008] When the cell containing the sample is immersed in a cryogenic fluid, a portion of its volume is cooled to the analysis temperature (cold volume) while another portion of the cell is maintained at room temperature (warm volume).

[0009] In order to accurately calculate the amount of adsorption, these volumes need to be known. These volumes are usually calculated by using a non-adsorbing gas (usually helium), which is used to measure before the adsorption analysis begins or after the adsorption analysis ends.

[0010] However, these volumes need to be constant throughout the adsorption analysis (or their change during the adsorption analysis needs to be known) in order to accurately calculate adsorption. However, as the cryogenic fluid evaporates, the portion of the tank immersed in the cryogenic fluid will change over time, thereby changing the cold volume / warm volume fraction over time.

[0011] To overcome this challenge, different adsorption instrument manufacturers have developed and implemented different approaches.

[0012] A possibility of maintaining constant volume known in the art is to maintain the cryogenic fluid level relative to the sample tank constant by changing the position of the cryogenic liquid retainer. This arrangement uses a cryogenic liquid level probe and a motorized system, which moves the cryogenic liquid retainer (Dewar flask) upward at the same speed as the fluid evaporation. The benefit of this system is that the part of the sample tank immersed in the cryogenic fluid can be kept at a minimum, ensuring that the sample is at the cryogenic fluid temperature. The smaller the part of the sample tank volume at low temperatures, the better the accuracy of the adsorption measurement (see the calculation of the influence of cold volume on adsorption absorption accuracy below). The disadvantage of this system is that, due to the upward movement of the Dewar flask over time, the temperature gradient in the part of the sample tank that is not immersed in the cryogenic fluid changes over time, requiring additional correction.

[0013] Such a temperature control system is disclosed, for example, in US Pat. No. 6,387,704.

[0014] A second possibility known in the art for maintaining a constant volume immersed in a cryogenic liquid in a sample tank is to surround the portion of the sample tank extending above the liquid surface with a wick. This arrangement is disclosed in U.S. Pat. No. 4,693,124 to Killip et al. Using this configuration, even if the liquid level of the cryogenic fluid relative to the sample tank decreases due to evaporation, the portion of the sample tank volume that is cooled to the temperature of the cryogenic fluid is constant. This is because the wicking material locally raises the liquid level of the cryogenic fluid to the upper end of the wick and rises toward the upper end of the sample tank. The disadvantage of this system is that the portion of the sample tank volume that is maintained at a low temperature must be greater than the portion obtained by the previous arrangement.

[0015] In the third method known in the art, the liquid level of the cryogenic fluid is not controlled, but the change of cold volume / warm volume fraction is calculated continuously. For this reason, an empty slot grid similar to the slot for keeping the sample is added to the system. The empty slot is filled with non-condensable gas, and the pressure change caused by the evaporation of the cryogenic fluid is followed and used to correct the cold volume / warm volume fraction change in the sample slot. The benefit of this method is that there is no need to strictly control the cryogenic fluid level. The disadvantage is that it requires additional hardware (groove, pressure transducer, electronic equipment ...), making it a more expensive system, and in fact the cold volume obtained is very large, and the inventor finds that this is undesirable for accurate adsorption analysis. The above method is used for the commercialized instrument of Microtrac BEL Corp., a subsidiary of NIKKISO CO., LTD.8-2-52 Nanko-Higashi, Suminoe-ku, Osaka 559-0031, Japan.

[0016] There are other methods in the literature (see WO 2017109246, Ramos et al.) that keep the level of cryogenic liquid constant by using a pump installed in the Dewar flask to circulate the fluid to a higher level or other methods based on replenishing the cryogenic fluid at the same rate as evaporation. Summary of the invention

[0017] It is therefore an object of the present invention to provide a device for maintaining a constant temperature in a sample cell while keeping the portion of the sample cell volume at the temperature of the cryogenic liquid to a minimum. The device for maintaining a constant temperature in a sample cell overcomes the above-mentioned disadvantages of devices and methods of this general type known hitherto and improves the resolution of adsorption measurements.

[0018] The present invention proposes a device for maintaining a constant temperature in a vessel, wherein the vessel is isolated from a liquid directly immersed in a sub-ambient temperature. The device has an intermediate component made of a material having both wicking properties and insulating properties. An inverted core encapsulates the sample portion of a sample vessel (trough) and extends downward into a cooling liquid. The interior of the inverted core is porous and allows the cooling liquid to be transferred to the vessel and allows heat to be transferred from the vessel to the cooling liquid. The exterior of the inverted core is sealed, ideally sealed with a polymer film, which allows the inverted core to insulate the cooling liquid from an external thermal gradient present in a Dewar flask, because the cooling liquid level drops over time due to evaporation, and forces the evaporation of the cooling liquid to occur in the top surface of the core.

[0019] The advantage provided by this method over prior art techniques such as that found in U.S. Patent No. 4,693,124 is that it improves the accuracy of analysis performed using a scientific sorption analyzer by minimizing the volume of the vessel maintained at low temperature, wherein the gas pressure measured within the vessel is used to calculate the physical properties of the material by using gas laws (commonly expressed as PV=nRTZ).

[0020] Minimising the 'cold volume' used in such analyses means that any interaction between the analysis gas and the sample has a greater effect on the pressure in the vessel, so the sensitivity of the analyser is improved.

[0021] Adsorption analysis is performed by dispensing the adsorbed gas from the manifold into a previously emptied sample reservoir. The amount of adsorption can be calculated using the following formula:

[0022]

[0023] in,

[0024] The mole fraction adsorbed after distribution i from the manifold

[0025] In step i, the mole fraction of the sample from the manifold is

[0026] P i : The pressure in the sample tank after partitioning i

[0027] V cell : Sample tank volume

[0028] x: fraction of the sample tank at the analysis temperature

[0029] T A :Analysis temperature (K)

[0030] T R :Room temperature(K)

[0031] The adsorbate is at the analysis temperature and pressure P i The compression factor

[0032] The adsorbate at room temperature and pressure P i The compression factor

[0033] For simplicity, we can assume ideal behavior of the gas, so:

[0034]

[0035] To calculate the error associated with the accuracy of the pressure transducer in the tank, the partial derivative of the adsorbed absorption with respect to the measured pressure is performed:

[0036]

[0037] Assuming the instrument is in a 25°C room and the cooling liquid is liquid nitrogen at -196°C:

[0038] T A ≈77K, T R ≈298K→T R ≈3.87T A

[0039]

[0040] And simplify:

[0041]

[0042] It is not difficult to see from this formula that, for a fixed cell volume, the smaller the fraction of the sample cell that is at the analysis temperature (x), the smaller the error in the calculated adsorption absorption associated with the accuracy of the pressure transducer.

[0043] In view of the above and other purposes, a sample vessel assembly is provided to perform sorption analysis in a container provided with a cooling liquid. The sample vessel assembly includes a sample vessel configured to be suspended in the container. The sample vessel has a sample holding area at the sample end of the container to hold the sample to be analyzed. The core is arranged on the sample vessel and surrounds the sample holding area. When the sample vessel is arranged in the analysis position in the container, the core extends from the sample holding area to extend toward the bottom of the container and sucks the cooling liquid above the sample holding area.

[0044] According to another feature of the invention, the core comprises a core base and a core cover engaged with the core base. The core base and the core cover define a cavity therebetween. The cavity is sized to receive a sample holding area therein.

[0045] According to a further feature of the invention, the sample vessel has a stem for inserting the sample into the sample vessel, and the core cover has a hole formed therein to receive the stem and allow the cover to slide along the stem to the core base.

[0046] According to a further feature of the invention, the sample vessel has a stem with straight walls and the sample holding area has a bulbous portion defined by a diameter that expands relative to the stem.

[0047] According to an additional feature of the invention, the core base has a cavity formed therein. The height of the cavity is sized to receive the bulbous portion and the core cap therein.

[0048] According to an additional feature of the invention, the core cover has a cavity formed therein. The core base has an outer surface with a step, the step defining a shoulder. The core cover has an end that abuts the shoulder when the core cover is placed on the core base.

[0049] According to another mode of the invention, the sample vessel is a substantially straight-walled sample vessel and the core is a cylindrical core having a cavity for receiving the sample vessel.

[0050] According to a further mode of the invention, a stop is provided in order to establish the position of the end of the core at the upper limit of the sample holding area when the core is placed on the sample vessel.

[0051] According to an additional mode of the invention, the stop is defined by a marking provided on the sample vessel, which marking indicates the alignment position of the core.

[0052] According to yet another feature of the invention, the stop is a mechanical stop defined by a recess in the sample vessel and a pin in the core, the pin engaging the recess to set the core at the upper limit when the core is placed on the sample vessel.

[0053] According to yet another further feature of the invention, the stop comprises a protrusion on the sample vessel, and the top edge of the core engages the protrusion to set the core at the upper limit when the core is placed on the sample vessel.

[0054] According to yet another additional feature of the invention, the core has a blind hole with a depth, which defines a stop by engaging with the sample end when the core is placed on the sample vessel.

[0055] According to yet another additional feature of the invention, the core is arranged at a position on the sample vessel such that its end begins at the top of the sample holding area to define a cold volume, which substantially corresponds to the sample holding area.

[0056] According to yet another further feature of the invention, the core is covered by an insulating material.

[0057] In view of the objects of the present invention, there is also provided a wick assembly for a sample vessel including a sample holding area having a sample undergoing sorptive analysis.

[0058] The assembly includes a core base and a core cover engaging the core base. The core base and the core cover define a cavity therebetween. The cavity is sized to receive a sample holding area therein.

[0059] According to a further mode of the invention, the core cover has a hole formed therein to receive the stem of the sample vessel and allow the cover to slide along the stem to the core base.

[0060] According to yet another additional feature of the present invention, the core base has a cavity formed therein. The cavity has an inner diameter for receiving the outer diameter of the core cover.

[0061] In another feature of the invention, the core cover has a cavity formed therein. The core base has an outer surface with a step, the step defining a shoulder. The core cover has an end that abuts the shoulder when the core cover is placed on the core base.

[0062] In view of the purpose of the present invention, a method for performing sorption analysis is also provided. The method includes providing a sample vessel having a sample holding area at the end of the vessel. A core is provided on the sample vessel above the sample holding area. The core extends away from the vessel from the end of the vessel.

[0063] According to another mode of the invention, the method comprises providing a container with a cooling liquid filled to a level. A sample vessel having a core is placed in the container at a position in which the core is directed toward the bottom of the container so that the end of the core is below the level of the cooling liquid.

[0064] Other features which are considered as characteristic for the invention are set forth in the appended claims.

[0065] Although the present invention is illustrated and described herein by way of example as an apparatus for maintaining a constant temperature in a sample tank, it is not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope of the claims and equivalents.

[0066] The invention, however, both as to its construction and method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] FIG1 is a cross-sectional view of a prior art device having a core extending along a sample vessel above the liquid level in a Dewar flask;

[0068] Figure 2A and Figure 2B is a cross-sectional view of a prior art device, corresponding to which the liquid level in the Dewar flask is controlled to maintain a cold zone;

[0069] Figure 3 is a cross-sectional view of an embodiment according to the present invention having a substantially solid core;

[0070] Figure 4 is a cross-sectional view of an embodiment according to the present invention having a substantially tubular core; and

[0071] Figure 5 is a cross-sectional view of another embodiment according to the present invention having a substantially solid core;

[0072] Fig. 6A yes Figure 4 An enlarged portion of the embodiment of the stopper is shown;

[0073] Figure 6B yes Figure 4 An enlarged portion of the embodiment of the stopper is shown;

[0074] Figure 6C yes Figure 4 An enlarged portion of the embodiment of the stopper is shown;

[0075] Fig.6D yes Figure 4 An enlarged portion of FIG. 1 shows another embodiment of the stopper; and

[0076] Fig. 6E yes Figure 4 An enlarged portion of FIG. 1 shows another embodiment of the stop portion. DETAILED DESCRIPTION

[0077] FIG1 shows an apparatus 1 as disclosed by Killip et al. Here, a container is provided as a Dewar flask 2 and is filled to a liquid level U with an evaporating cooling liquid CL such as liquid nitrogen. As the time of the analysis passes, it can be seen that the liquid level of the cooling liquid CL drops to a lower liquid level L2. A sample vessel 3 is provided for holding a sample S therein at a sample holding zone SHR at the bottom of the sample vessel 3. The sample vessel 3 has a core 4 disposed on the sample vessel 3. As shown in FIG1 , the core 4 starts at a position above the sample holding zone SHR and extends upward therefrom to a height above the liquid level L1 of the cooling liquid CL. The sample holding zone SHR is disposed at the bottom of the bottle 2 and is directly exposed to the cooling liquid CL. When the cooling liquid CL evaporates, the core 4 draws the cooling liquid CL onto the core 4 and maintains a longer cold zone CZ over the length of the core 4 and over the portion of the sample vessel 3 extending from the core 4 and immersed in the cooling liquid CL. According to the configuration of Killip et al., as the level of the cooling liquid CL decreases over the length of the core, a longer cold zone CZ is allowed to be maintained. However, in the study of Killip et al., the sample holding region SHR of the sample vessel 3 was always immersed in the cooling liquid CL during sample analysis.

[0078] Figure 2A and Figure 2B An alternative arrangement 1 is shown for maintaining a shorter cold zone CZ (over the length of the sample holding zone) while accommodating evaporation of the cooling liquid CL.

[0079] In particular, Figure 2A The Dewar 2 is shown in a position at the beginning of the sample analysis. The device 1 includes a probe 7, which is in contact with the surface of the cooling liquid CL. The height position of the Dewar 2 is set by a displaceable lifter (not shown) on which the Dewar 2 is placed. The lifter is configured to be controlled by the reading of the probe 7 and the corresponding electronic circuit. In this regard, the lifter is raised to maintain the contact of the cooling liquid CL with the probe 7. This in turn provides an attempt to maintain the level of the cooling liquid CL at a constant position relative to the sample vessel 3, thereby maintaining the cold zone CZ at a constant temperature and a constant cold volume as much as possible. Figure 2B A point in time in the analysis is shown, namely after the level of the cooling liquid CL has dropped to a level L2 which is lower than the level L1. It can be seen here that the Dewar 2 is raised in height and that the sample vessel 3 is closer to the bottom of the Dewar 2. Figure 2A and Figure 2BThe device 1 is limited by the ability of the probe 7 and the lifter to react to a drop in the level of the cooling liquid CL. However, this creates a problem because a large part of the warm volume is inside the Dewar, which will cause a small change in the average temperature of the warm volume, thus requiring an additional correction. Therefore, an additional calculation correction is required to compensate for this change. Such a correction requires the expenditure of additional components.

[0080] In the present invention, the core 4 is disposed on the sample vessel and surrounds the sample holding area SHR, the core 4 extends from the sample holding area SHR to extend toward the bottom of the container 2, and draws the cooling liquid CL onto the sample holding area SHR when the sample vessel 3 is disposed in the analysis position in the container 2. The core 4 is provided with a cavity 4c for receiving the sample holding area SHR of the sample vessel 3.

[0081] The core 4 may be a plastic that performs well at low temperatures, such as ultra high molecular weight polyethylene with a porosity of 10 microns in average diameter, but other materials may be used. The important property is the porosity of the material, which is preferably between 1 and 50 microns in average diameter.

[0082] Figure 3 A first embodiment of the device 1 is shown, in which a substantially solid core base 4b is provided. The core 4 may be provided with an outer insulating layer 4i. Figure 3 As shown, the Dewar 2 is provided with a sample vessel 3 suspended therein. The sample vessel 3 has a straight-walled stem 3s which expands into a bulbous sample holding area SHR at the base of the sample vessel 3. The cooling liquid CL is shown to have a liquid level L1 at the start of the analysis and a liquid level L2 at a subsequent point in time in the analysis after a certain amount of the cooling liquid CL has evaporated. Due to the construction according to the invention, even the liquid level L1 at the start of the analysis may be lower than the sample vessel 3. Figure 3 In the embodiment of the present invention, the core base 4b is solid except for the cavity 4c, which accommodates the sample holding area SHR of the sample vessel 3. The cover or plug 4p is arranged on the rod 3s of the sample vessel 3 and plugs the cavity 4c by matching the inner diameter of the cavity 4c and encloses the sample holding area SHR from above. The plug 4p is provided with a hole 4pa for accommodating the rod 3s of the sample vessel 3. The height of the cavity 4c is sized to receive the bulbous sample holding area and the plug 4p therein. Therefore, the sample S contained in the sample holding area SHR is surrounded by the core 4 and the cold zone CZ corresponds to at least the sample holding area SHR.

[0083] Figure 5Different embodiments are shown, wherein the cavity 4c is disposed in a cover 4p, which is disposed on the rod 3s of the sample vessel 3. Here, the cover 4p has an ID that engages with the outer diameter of the core base 4b. The cover 4p has a shoulder that encloses the sample holding area from above and defines a hole 4pa for receiving the rod 3s. The outer surface of the core base 4b has a step that defines a shoulder, and when the core cover 4p is disposed on the core base 4b, the core cover 4p has an end adjacent to the shoulder. In two embodiments, the cover / plug 4p has a tight fit for engaging the core base 4b to allow the user to attach / remove by hand.

[0084] In contrast to the prior art, the core 4 of the present invention covers the sample holding area SHR and extends from the sample end 3e of the sample vessel and protrudes downward toward the bottom of the Dewar 2 (i.e., an inverted core). The bottom end of the core 4 is preferably spaced apart from the bottom surface of the Dewar 2. When the liquid level of the cooling liquid CL in the Dewar 2 decreases due to the evaporation of the cooling liquid CL, the core 4 draws up the cooling liquid CL by capillary action to overcome gravity. This allows the cooling liquid CL to be maintained around the sample vessel 3 over the length of the core 4 surrounding the sample vessel 3, and a constant temperature is obtained over the length of the sample vessel 3 surrounded by the core 4, even if the cooling liquid is at a level L2 far below the initial liquid level L1 of the cooling liquid CL. In other words, the present invention provides a constant and small cold volume for the sample holding area SHR. The construction based on the inverted core allows a constant temperature to be maintained in the sample holding area SHR of the sample vessel 3, even if the cooling liquid CL decreases due to evaporation. The temperature at the sample holding region SHR is kept constant without the need for additional probes and / or mechanisms / circuits to lift the Dewar 2 during evaporation of the cooling liquid CL while keeping the cold volume to a minimum. The configuration of the present invention also eliminates the need for additional probes and / or mechanisms / circuits to lift the Dewar 2 during evaporation of the cooling liquid CL while keeping the cold volume to a minimum. Figure 2A and Figure 2B The arrangement shown in FIG. 4 maintains a constant immersion level of the sample vessel 3 without the need for additional calculation corrections for changes.

[0085] Figure 4 An embodiment is shown in which the cavity 4c of the core 4 extends through the entire length of the core 4. Another difference of this embodiment is that the sample vessel 3 has straight side walls, while Figure 3 The sample vessel 3 in the embodiment has a bulbous sample holding area. Figure 4 In the case of a 3D printed circuit board, the core is tubular. Figure 4 In the embodiment, a stopper 13 may be provided for establishing the position of the end of the core 4 at the upper limit of the sample holding region SHR when the core 4 is placed on the sample vessel 3. Fig. 6A As shown, the stop 13 may be defined by a mark 13 provided on the sample vessel 3, the mark 13 indicating the alignment position of the core 4. Alternatively, as Figure 6BAs shown, the stop 13 may be defined by one or more protrusions 13 p on the sample vessel 3 , against which the end of the core 4 abuts to set the upper position of the core 4 .

[0086] like Figure 6C As shown, a pin 14p is provided in the core 4, which engages the sample vessel 3 for applying a frictional holding force against the sample vessel 3. In particular, the pin 14p is embedded in the core 4 so that the pin 14p presses the core 4 at its tangent point with the sample vessel 3, thereby fixing the core 4 to the sample vessel 3 more firmly. Fig.6D As shown, the stop 13 may include one or more recesses 13i on the sample vessel 3. Here, the pin 14p is arranged to engage the recess 13i to set the core 4 at the upper limit when it is placed on the sample vessel. Fig. 6E As shown, the core 4 can also have a cavity 4 c as a blind hole with a depth, so that when the core 4 is placed on the sample vessel 3 , the stop 13 is defined by engaging the sample end 3 e of the sample vessel 3 .

[0087] The present invention provides a method for performing sorption analysis. The method includes providing a sample vessel 3 having a sample holding area SHR at the end of the vessel. A core 4 is provided on the sample vessel 3 above the sample holding area SHR. The core 4 extends away from the vessel 3 from the end of the vessel 3. The method includes providing a container 2 having a cooling liquid CL filled to a liquid level, and placing the sample vessel 3 having the core 4 into a position in the container 2, in which the core 4 is directed toward the bottom of the container 2, wherein the end of the core 4 is below the liquid level of the cooling liquid CL.

Claims

1. A sample vessel assembly for performing sorption analysis in a container provided with a cooling liquid, wherein: The sample vessel assembly comprises: a sample vessel configured to be suspended within the container, the sample vessel having a sample holding area at a sample end of the sample vessel for holding a sample to be analyzed; A core is disposed on the sample vessel and surrounds the sample holding area, and when the sample vessel is disposed in an analysis position in the container, the core extends from the sample holding area to protrude toward the bottom of the container and draw the cooling liquid onto the sample holding area.

2. The sample vessel assembly of claim 1, wherein The core includes a core base and a core cover engaged with the core base, the core base and the core cover defining a cavity therebetween, the cavity being sized to receive the sample holding region therein.

3. The sample vessel assembly of claim 2, wherein The sample vessel has a stem for inserting a sample into the sample vessel, and the core cover has a hole formed in the core cover to receive the stem and allow the core cover to slide along the stem to the core base.

4. The sample vessel assembly of claim 2, wherein The sample vessel has a stem with straight walls, and the sample holding area has a bulbous portion defined by an expanded diameter relative to the stem.

5. The sample vessel assembly of claim 4, wherein The core base has the cavity formed therein, the cavity having a height sized to receive the bulbous portion and the core cap therein.

6. The sample vessel assembly of claim 4, wherein The core cover has the cavity formed therein, the core base has an outer surface with a step defining a shoulder, the core cover has an end abutting the shoulder when the core cover is disposed on the core base.

7. The sample vessel assembly according to any one of claims 1 to 6, wherein The sample vessel is a straight-walled sample vessel and the core is a cylindrical core having a cavity for receiving the sample vessel.

8. The sample vessel assembly of claim 7, further comprising A stop is provided for establishing the position of the end of the core at the upper limit of the sample holding area when the core is placed on the sample vessel.

9. The sample vessel assembly of claim 8, wherein The stop is defined by a marking provided on the sample vessel, the marking indicating an aligned position of the core.

10. The sample vessel assembly of claim 8, wherein The stop is a mechanical stop defined by a recess in the sample vessel and a pin in the core, the pin engaging the recess to set the core at an upper limit when the core is placed on the sample vessel.

11. The sample vessel assembly of claim 8, wherein The stop comprises a protrusion on the sample vessel, and a top edge of the core engages the protrusion when the core is placed on the sample vessel to set the core at an upper limit.

12. The sample vessel assembly of claim 8, wherein The core has a blind hole with a depth that defines the stop by engaging with the sample end when the core is placed on the sample vessel.

13. The sample vessel assembly according to any one of claims 1 to 6, wherein The core is disposed at a position on the sample vessel such that an end of the core begins at a top of the sample holding area to define a cold volume, the cold volume corresponding to the sample holding area.

14. The sample vessel assembly according to any one of claims 1 to 6, wherein The core is covered with an insulating material.

15. A wick assembly for a sample vessel comprising a sample holding area having a sample undergoing sorption analysis, wherein: The core component comprises: core base; a core cover engaged with the core base, the core base and the core cover defining a cavity therebetween; The cavity is sized to receive the sample holding area therein.

16. The core component according to claim 15, wherein The core cover has a hole formed therein to receive the stem of the sample vessel and allow the core cover to slide along the stem to the core base.

17. A core component according to claim 15 or 16, wherein The core base has the cavity formed therein having an inner diameter for receiving an outer diameter of the core cover.

18. A core component according to claim 15 or 16, wherein The core cover has the cavity formed therein, the core base has an outer surface with a step defining a shoulder, the core cover has an end abutting the shoulder when the core cover is disposed on the core base.

19. A method for performing sorption analysis, wherein: The method comprises: providing a sample vessel having a sample holding area at an end of the sample vessel; A core is disposed on the sample vessel above the sample holding area, the core extending from an end of the sample vessel away from the sample vessel.

20. The method according to claim 19, further comprising: providing a container having a cooling liquid filled to a level; The sample vessel with the core is placed into the container in a position in which the core is directed towards the bottom of the container so that the end of the core is below the level of the cooling liquid.

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