JP5916580B2 - Adsorption characteristic measuring device - Google Patents

Description

  The present invention relates to an adsorption characteristic measuring apparatus, and more particularly to an adsorption characteristic measuring apparatus provided with a cooling means for cooling a sample.

  Since the amount of adsorption generally increases at low temperatures, the sample is brought to a low temperature state when measuring adsorption characteristics. For example, Patent Document 1 describes that a sample tube is immersed in liquid nitrogen filled in a Dewar bottle as an adsorption amount measuring device in order to measure the adsorption amount.

JP-A-5-87727

  When measuring the adsorption characteristics, the adsorption temperature is set near the vaporization temperature of the adsorbate. For this reason, for example, 77K (-196 ° C) liquid nitrogen is used when nitrogen is adsorbed, and 87K (-189 ° C) liquid argon is used when argon is adsorbed. Thus, conventionally, it has been necessary to prepare low-temperature refrigerants having different vaporization temperatures for each adsorbate. Also, since the vaporization temperatures of the available low-temperature refrigerants are unique vaporization temperatures, it was difficult to measure the adsorption characteristics at any temperature or to evaluate the adsorption characteristics by continuously changing the measurement temperature. .

  An object of the present invention is to provide an adsorption characteristic measuring apparatus capable of arbitrarily setting the measurement temperature of the adsorption characteristic. Another object is to provide an adsorption characteristic measuring apparatus capable of continuously changing the measurement temperature of the adsorption characteristic. Still another object is to provide an adsorption characteristic measuring apparatus that enables measurement of heat of adsorption. The following means contribute to at least one of these purposes.

  An adsorption characteristic measuring apparatus according to the present invention is connected to at least an adsorbate supply unit, accommodates a sample, has a predetermined high heat transfer property, a regenerative cooling means having a cooling stage for cooling the sample, and A heat transfer buffer provided between the sample chamber and the cooling stage and having a predetermined heat capacity and a predetermined high heat transfer property; and a heat input section provided between the heat transfer buffer and the sample chamber for heat input to the sample chamber; Temperature adjustment means for controlling the amount of heat input so that the deviation between the set target adsorption measurement temperature and the sample chamber temperature is zero, and measurement means for measuring the adsorption characteristics of the sample under the target adsorption measurement temperature And.

  In the adsorption characteristic measuring apparatus according to the present invention, it is preferable to include a vacuum heat insulation chamber that accommodates the sample chamber, the heat input section, the heat transfer buffer, and the cooling stage.

  In the adsorption characteristic measuring apparatus according to the present invention, it is preferable that the temperature adjusting means sets the target adsorption measurement temperature in units of (1/1000) K.

  Moreover, in the adsorption | suction characteristic measuring apparatus which concerns on this invention, it is preferable that a cool storage type cooling means is a Stirling refrigerator or a GM refrigerator.

  In addition, the adsorption characteristic measuring apparatus according to the present invention preferably includes an adsorption heat calculation unit that obtains the heat of adsorption when the adsorbate is adsorbed to the sample based on the heat input amount of the heat input part during the adsorption characteristic measurement.

  According to the adsorption characteristic measuring apparatus having the above configuration, the temperature of the sample chamber can be adjusted by the amount of heat sucked by the regenerative cooling means and the amount of heat supplied by the heat input section. Therefore, the measurement temperature of the adsorption characteristic can be arbitrarily set within a certain range determined by the cooling capacity of the regenerative cooling means, and the measurement temperature of the adsorption characteristic can be continuously changed.

  The adsorption characteristic measurement device vacuums the elements related to heat input / output and heat transfer, such as the cooling stage that sucks the heat of the sample chamber to cool the sample, the heat input part that applies heat to the sample chamber, the sample chamber, and the heat transfer buffer. Since it is housed inside the heat insulation chamber, it is possible to block heat dissipation to the outside, heat transfer from the outside, and heat transfer from the inside. Thereby, thermal noise can be reduced and the measurement temperature of adsorption | suction characteristics can be adjusted.

  The adsorption characteristic measuring apparatus can adjust the temperature in units of (1/1000) K. In conventional liquid refrigerants such as liquid nitrogen, fluctuations of 0.2K may be observed due to changes in atmospheric pressure during measurement, oxygen penetration in the air, etc., but the adsorption characteristic measuring device measures the adsorption characteristic measurement temperature. Can be managed more than conventional liquid refrigerants such as liquid nitrogen.

  In the adsorption characteristic measuring apparatus, a Stirling refrigerator or a GM refrigerator is used as the electric cooling means. The Stirling refrigerator is small, and the cooling temperature can be set in the range of 50K to room temperature. The GM refrigerator is larger than the Stirling refrigerator and can cool to about 4.2K. By using these, it is possible to provide a compact adsorption characteristic measuring apparatus that can vary the measurement temperature of the adsorption characteristic.

  In the adsorption characteristic measuring apparatus, if heat is generated during the measurement of the adsorption characteristic, the heat input amount of the heat input part is lowered so as to keep the target temperature constant. From the change in the amount of heat input, the heat of adsorption when the adsorbate is adsorbed to the sample can be obtained. Thereby, the heat of adsorption can be measured in real time without using a special heat measuring device.

It is a block diagram of the adsorption | suction characteristic measuring apparatus in embodiment which concerns on this invention. In embodiment which concerns on this invention, it is a figure which shows the time change of the temperature of each element, and calorie | heat amount.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In the following, a Stirling refrigerator is described as the regenerative cooling means. However, any cryogenic refrigerator capable of electrical control may be used. For example, a GM refrigerator, a pulse tube refrigerator, or the like may be used.

  In addition, the dimensions, object shapes, and the like described below are illustrative examples, and specific shapes, numerical values, and the like can be changed as appropriate according to the application, purpose, and specifications of the adsorption characteristic measurement device. . Below, the same code | symbol is attached | subjected to the same element in all the drawings, and the overlapping description is abbreviate | omitted. In the description in the text, the symbols described before are used as necessary.

  FIG. 1 is a configuration diagram of the adsorption characteristic measuring apparatus 10. FIG. 1 shows a sample 8 that is not a constituent element of the adsorption characteristic measuring device 10 but whose adsorption characteristic is measured.

  The adsorption characteristic measuring apparatus 10 includes a Stirling refrigerator 20 that is a regenerative cooling means, a main body 30, a pipe 80, and a controller 100 that controls these operations.

  The Stirling refrigerator 20 is a kind of a cryogenic refrigerator using refrigerant gas, and in particular, a kind of a cryogenic refrigerator using helium as a refrigerant. In the Stirling refrigerator 20, a compressor and an expander are arranged via a regenerator, the compression piston and the expansion piston are driven while maintaining a phase of 90 degrees, and the cooled refrigerant located between the compression piston and the expansion piston. Is a regenerative cryogenic refrigerator that cools the regenerator by passing through the regenerator.

  The Stirling refrigerator 20 includes an external compressor 22, an external expander 24, a cylinder part 26, and a cooling stage 28. The external compressor 22 corresponds to a compressor constituting a cryogenic refrigerator, and the external expander 24, the cylinder unit 26, and the cooling stage 28 are integrated with an expander and a regenerator constituting the cryogenic refrigerator. Thus, the cylinder part 26 has an expansion space that cools by inflating helium gas and a regenerator. The external expander 24 includes a part of the cylinder part 26 and holds it. The cooling stage 28 is a tip portion that is cooled to an extremely low temperature by the expansion space, and a cooling target is attached to the cooling stage 28. Here, it has a function of cooling the sample 8 via a heat transfer buffer 60 described later.

  The cooling stage 28 is a part of the constituent elements of the Stirling refrigerator 20 and serves as an interface between the Stirling refrigerator 20 and the object to be cooled. The temperature of the cooling stage 28 is substantially the same as the set temperature of the Stirling refrigerator 20. The size of the cooling stage 28 can be 3 cm in outer diameter and 0.3 cm in height.

  The cylinder part 26 and the cooling stage 28 are accommodated in a vacuum heat insulation chamber 32 constituting the main body part 30 because it is desired to suppress the exchange of heat with the surroundings as much as possible. Since the external compressor 22 and the external expander 24 need to dissipate heat, they are disposed outside the vacuum heat insulation chamber 32.

  The Stirling refrigerator 20 can set a target temperature in a temperature range from 50K to room temperature, but a temperature fluctuation of about ± 1K occurs with respect to the set temperature. In the case of the GM refrigerator, the target temperature cannot be set, and the low temperature at which the piston reaches by the one-stage type or the two-stage type is about 20K and 4.2K, respectively. For this reason, for temperature control, sapphire is used for the heat transfer buffer to deteriorate the thermal conductivity near room temperature, or a large heat input part is installed to control near room temperature.

  The main body 30 includes a vacuum heat insulation chamber 32, a vacuum pump 40, a sample chamber 42, a heat transfer buffer 60, and a heat input unit 64.

  The vacuum heat insulation chamber 32 reflects the heat flow from the outside to the inside by the outer peripheral surface, reflects the heat flow from the inside to the outside by the inner wall surface, and accommodates the housing space surrounded by the inner wall surface by making a vacuum. It is a hermetically sealed vacuum heat insulating container that suppresses heat exchange between elements disposed in the space. The vacuum insulation chamber 32 is a combination of two bodies, a lower container 36 and an upper container 34. The lower container 36 and the upper container 34 are fixed by a clamp 38 after the combined surfaces are aligned. The accommodation space becomes a sealed space. The vacuum pump 40 is an exhaust device that holds the inside of the vacuum heat insulation chamber 32 in a vacuum.

  In the accommodation space of the vacuum heat insulation chamber 32, there are a cylinder part 26, a cooling stage 28, a heat transfer buffer 60, a heat input part 64, a sample chamber 42, and a connecting part for thermally connecting them. Be contained. As connecting parts, a cylindrical part 62 that connects the cooling stage 28 and the heat transfer buffer 60, a cap part 66 that connects the heat transfer buffer 60 and the heat input part 64, and a heat transfer member that connects the heat input part 64 and the sample chamber 42. 68 mag. The vacuum pump 40 is an exhaust device that holds the inside of the vacuum heat insulation chamber 32 in a vacuum.

The heat transfer buffer 60 is a cylindrical member that is disposed on the cooling stage 28 and has a predetermined heat capacity. The cooling stage 28 undergoes temperature fluctuation during the operation of the Stirling refrigerator 20. For example, if the set temperature of the Stirling refrigerator 20 and theta _20, by the reciprocating motion or the like of the cylinder portion 26 of the Stirling cooler 20, is a value temperature fluctuates ± 1K around a theta ₂₀ of the cooling stage 28 as it is. The heat transfer buffer 60 absorbs the temperature fluctuation and stabilizes the temperature of the heat transfer member 68 to about ± 2 mK by combining the control of heat input.

  The material of the heat transfer buffer 60 is made of sapphire. Any material other than sapphire may be used as long as it has a high thermal conductivity. For example, copper or a copper alloy can be used. An example of the dimensions of the heat transfer buffer 60 is an outer diameter of 1.5 cm and a height of 5 cm. The shape of the heat transfer buffer 60 may be other than a cylindrical shape.

  The cylindrical portion 62 is a cylindrical member having an inner diameter that is substantially the same as the outer diameter of the heat transfer buffer 60. The cylindrical portion 62 is a member for placing the heat transfer buffer 60 on the cooling stage 28 and thermally connecting it. The cylindrical portion 62 is fixed to the cooling stage 28, and the heat transfer buffer 60 is inserted into the inner diameter portion thereof so that the upper surface of the cooling stage 28 and the bottom surface of the heat transfer buffer 60 are in contact with each other. The cooling stage 28 and the heat transfer buffer 60 are thermally connected. If necessary, the cylindrical portion 62 and the heat transfer buffer 60 and the space between the heat transfer buffer 60 and the cooling stage 28 may be fixed with an appropriate fixing member. The dimension of the cylinder part 62 is set so that the upper surface of the heat transfer buffer 60 protrudes from the cylinder part 62 in a state where the heat transfer buffer 60 is inserted into the inner diameter part of the cylinder part 62. The material of the cylindrical part 62 can be copper or a copper alloy. It is also effective to make the surface a mirror surface by Ni plating or the like and reflect the radiant heat.

  The cap portion 66 is a cap-shaped member that is placed on the upper surface of the heat transfer buffer 60, and a heater that is the heat input portion 64 is wound around the cap portion 66. The material of the cap part 66 can be copper or a copper alloy. It is also effective to make the surface a mirror surface by Ni plating or the like and reflect the radiant heat.

  The heat input part 64 is a resistance wire heater that is wound around a cap part 66 and covered with a heat transfer member 68 with a thin wire having an outer diameter of 1 mm covered with stainless steel as an example. The heat input section 64 has a function of adjusting the temperature of the sample chamber 42 by supplying heat to the sample chamber 42 via the heat transfer member 68, thereby adjusting the amount of heat drawn from the sample chamber 42 by the cooling stage 28. Have. Both terminals of the heater are connected to a heating power source whose operation is controlled by the control unit 100.

  As the resistance wire heater of the heat input section 64, a film heater of about 20 W can be used. A heater other than the film heater may be used. For example, a sheathed heater or a nichrome wire wound around the cap portion 66, or an insertion hole may be provided in the cap portion 66 to insert a cartridge type heater.

  The heat transfer member 68 is a member that is provided between the heat input portion 64 and the pedestal portion 44 and covers and holds the outside of the resistance wire heater wound around the cap portion 66. Although the heat transfer member 68 has a role of holding the resistance wire heater, the amount of heat sucked into the cooling stage 28 via the heat transfer buffer 60 and the heat input unit 64 are supplied from the heat flow to the sample chamber 42. It is a member that mixes the amount of heat.

  The material of the heat transfer member 68 can be copper or a copper alloy. Further, other materials may be used as long as the materials have high heat conductivity. An example of the dimensions of the heat transfer member 68 is an outer diameter of 5 cm and a height of 3 cm. Of the height of 3 cm, the height portion covering the outer periphery of the heat input section 64 is 2 cm. In addition, the shape of the heat transfer member 68 can have a suitable shape according to a measurement.

  The sample chamber 42 includes a pedestal portion 44, a lid portion 46, an accommodation space 48 formed by the pedestal portion 44 and the lid portion 46, and a sample stage 50 disposed in the accommodation space 48. The pedestal 44 and the lid 46 have a sealing mechanism and bolts for exchanging the sample and holding the vacuum.

  The pedestal portion 44 is a disk-shaped member attached to the upper surface of the heat transfer member 68 and forms an accommodation space 48 in cooperation with the lid portion 46 provided on the upper surface side thereof. In FIG. 1, the upper surface of the pedestal portion 44 is a flat surface, and a lid portion 46 with a flange and having a recess is used. On the contrary, a cylindrical protrusion may be provided on the pedestal portion 44, the cylindrical upper opening may be covered with a flat lid portion, and the cylindrical inner diameter portion may be used as the accommodation space 48. Although the number of accommodation spaces is one in FIG. 1, other accommodation spaces may be used. For example, two storage spaces may be provided, or three or more storage spaces may be provided. The material of the pedestal 44 and the lid 46 can be copper or a copper alloy. It is also effective to make the surface a mirror surface by Ni plating or the like and reflect the radiant heat.

  The sample stage 50 is a dish having an indentation for accommodating the sample 8 at the top. The sample stage 50 is disposed inside a storage space 48 that is a sealed space, and is detachable from the pedestal portion 44. Thereby, if the cover part 46 is removed, each sample stand 50 can be taken out, and cleaning etc. can be performed easily. Instead of this, the sample stage 50 may be integrated with the pedestal 44. An example of the size of the sample stage 50 is an outer diameter of 2.5 cm and a height of 0.8 cm.

The temperature detection unit 52 provided on the upper surface side of the pedestal unit 44 is a thermometer that measures the sample temperature θ _S that is the temperature of the sample table 50. The sample temperature θ _S is transmitted to the control unit 100 for calculation of adsorption characteristics. A platinum temperature detector can be used as the temperature detector 52.

The temperature detector 54 provided on the lower surface side of the pedestal 44 is a temperature for detecting the actual temperature θ _A when the temperature control of the sample chamber 42 is performed. The temperature control of the sample chamber 42 is performed based on the set temperature θ ₂₀ of the Stirling refrigerator ₂₀ and the heat input amount Q ₆₄ supplied by the heat input unit 64. The heat amount sucked from the sample chamber 42 by the Stirling refrigerator 20 and the heat input amount Q ₆₄ supplied by the heat input section 64 are combined at the heat transfer member 68 and transferred to the bottom surface side of the sample chamber 42. Therefore, the temperature on the bottom side of the sample chamber 42 is set as the actual temperature θ _{A in the} control, and the temperature detection unit 54 detects the actual temperature θ _A and transmits it to the control unit 100 through an appropriate signal line. A platinum temperature detector can be used as the temperature detector 54.

  It should be noted that there are many members such as the heat transfer buffer 60, the cylinder portion 62, the cap portion 66, the heat input portion 64, and the heat transfer member 68 between the cooling stage 28 and the sample chamber 42. Since these conduct heat by solid heat conduction, several contact surfaces are generated. Since this contact surface causes heat resistance, it is preferable to reduce the influence. In order to reduce the influence, the surface roughness of the contact surface is smoothed, a solid material having a high thermal conductivity is used, and the pressing force of the contact surface is increased. For example, in order to increase the pressing force, it is preferable to increase the fixing force between the elements or to apply grease that maintains high thermal conductivity even at extremely low temperatures. Further, in order to reduce the number of elements that conduct heat, the heat transfer member 68 and the sample chamber 42 may be integrated, or the cylinder portion 62, the cap portion 66, and the heat transfer member 68 may be integrated.

  The adsorbate supply unit 74 is a gas source that supplies adsorbate for measuring the adsorption characteristics of the sample 8. For example, when the adsorbate is nitrogen gas, the adsorbate supply unit 74 is a nitrogen gas cylinder. When there are a plurality of adsorbate types, a plurality of adsorbate supply units 74 are provided.

  The discharge unit 76 is an exhaust device for depressurizing the accommodation space 48 of the sample chamber 42 via the piping unit 80. The operation of the discharge unit 76 is performed under the control of the control unit 100. A rotary pump can be used as the discharge unit 76. Depending on the purpose of the adsorption characteristic measurement, a turbo molecular pump may be used and a rotary pump may be used as an auxiliary pump.

  The piping unit 80 includes a storage space 48 of the sample chamber 42 disposed inside the vacuum heat insulation chamber 32, an adsorbate supply unit 74 and a discharge unit 76 disposed outside the vacuum heat insulation chamber 32 via the manifold 82. These are a plurality of pipes provided to connect and connect to each other. The piping unit 80 is provided with a plurality of on-off valves 88, 92, and 94 that operate under the control unit 100.

  Of the piping unit 80, the piping between the adsorbate supply unit 74 and the manifold 82 is provided with an on / off valve 92 for adsorbate that operates under the control of the control unit 100. When there are a plurality of adsorbate supply units 74, an adsorbate opening / closing valve 92 is provided corresponding to each adsorbate supply unit 74. Similarly, a pipe between the discharge unit 76 and the manifold 82 is provided with a discharge unit on-off valve 94 that operates under the control of the control unit 100.

The manifold 82 is a bent pipe line in which one ends of the on-off valves 88, 92, 94 are connected to each other. The manifold 82 has an end on the side of the on-off valve 92 for the adsorbate and the on-off valve 94 for the discharge portion arranged outside the vacuum heat insulation chamber 32 and extends from there to enter the internal space of the vacuum heat insulation chamber 32 to provide a sample chamber. 42 side. A pressure gauge 86 connected to the manifold 82 detects the internal pressure P _M of the manifold 82. The pressure gauge 90 connected to the manifold 82 is a sample chamber pressure detecting means for detecting the internal pressure P _S of the accommodation space 48. The detected internal pressure P _M of the manifold 82 and the internal pressure P _S of the accommodation space 48 are transmitted to the control unit 100 through appropriate signal lines. It is preferable that the piping part 80 including the manifold 82 is accommodated in a temperature-adjusted tank and maintained at a predetermined temperature.

  The on-off valve 88 and the sample chamber 42 are connected by piping. This pipe preferably has a pipe inner diameter that can evacuate the sample, and a pipe having a thin outer diameter that can minimize heat inflow from the outside. In order to minimize the inflow of heat from the outside, it is preferable to have a mechanism for setting the temperature to be approximately the same as that of the sample chamber by a thermal anchor connecting the connection pipe and the cooling stage 28. The connecting part may be the cylinder part 26 or the cylinder part 62 which is a low temperature part.

  The control unit 100 is a device that controls the operations of these elements in an integrated manner. In particular, the operation of the heat input section 64 in the main body section 30, the Stirling refrigerator 20, the opening / closing valve 88 for the sample chamber in the piping section 80, the opening / closing valve 92 for the adsorbate, and the opening / closing valve 94 for the discharge section are controlled and absorbed. Executes control for performing characteristic measurement processing. The control unit 100 can be configured with a computer.

  The control unit 100 has a function of controlling the operation of each element of the adsorption characteristic measuring apparatus 10 as a whole, but here, in particular, by controlling the operation of the Stirling refrigerator 20 and the operation of the heat input unit 64, the adsorption unit It has a function of controlling the characteristic measurement temperature to a desired arbitrary temperature. Such a control unit can be configured by a computer.

Controller 100 calculates the target temperature setting procedure 102 for setting the target temperature theta _T, a temperature adjustment processing procedure 104 that performs temperature adjustment by controlling the operation of the Stirling refrigerator 20 and the heat input section 64, the adsorption properties Then, an adsorption characteristic calculation processing procedure 106 that is transmitted to the output unit 110 and an adsorption heat calculation processing procedure 108 that calculates the adsorption heat that is the amount of heat generated at the time of adsorption and transmits it to the output unit 110 are provided. Such a function can be realized by software, specifically, by executing a measurement processing program.

Adsorption characteristic calculation processing procedure of the control unit 100, the change in the internal pressure P _M of the manifold 82 to a pressure gauge 86 for the manifold is detected, change in the internal pressure P _S of the housing space 48 detected by the pressure gauge 90 for sample chamber Based on the above, the amount of adsorption of the sample 8 accommodated in the accommodation space 48 of the sample chamber 42 is calculated. The calculated adsorption characteristics include the amount of adsorption of the sample 8, the specific surface area, the pore distribution, and the like. The calculation of the adsorption characteristics, the program for calculating the amount of adsorption or the like based on the change and the internal pressure P _S of the housing space 48 of the internal pressure P _M changes the sample chamber 42 of the manifold 82 is used. The calculated adsorption characteristic is displayed on the output unit 110 which is an output terminal. The function of the output unit 110 may be part of the function of the control unit 100.

  The heat absorption calculation processing procedure of the control unit 100 uses the fact that the heat input of the heat input unit 64 decreases so as to keep the target temperature constant if heat is generated during the measurement of the adsorption characteristics. Calculation of the heat of adsorption when the adsorbate is adsorbed on the sample 8 from the change in the amount of heat is executed in real time as the adsorption proceeds. The calculated adsorption characteristic is displayed on the output unit 110 which is an output terminal. The adsorption heat measurement can be applied to the case where there is one sample chamber 42.

The operation of this configuration will be described with reference to FIG. FIG. 2 is a diagram showing changes over time, with time on the horizontal axis and the temperature and heat quantity of each element of the adsorption characteristic measuring apparatus 10 on the vertical axis. The time on the horizontal axis is a temperature control period during which adsorption is not yet started from time t ₀ to time t ₁ , and time t ₁ is an adsorption start time under temperature control.

FIG. 2A is a diagram showing the change over time of the calorific value Q ₈ of the sample 8 accommodated in the accommodation space 48. From time t ₀ to time t ₁ , no adsorbate is supplied to the accommodation space 48, and therefore the calorific value Q ₈ of the sample 8 is zero. At time t ₁ , the adsorbate is supplied, and heat is generated as the adsorbate is adsorbed on the sample 8. The calorific value Q _{8 at} this time is a value reflecting the heat of adsorption.

FIG. 2B is a diagram showing the target temperature θ _T as the measurement temperature of the adsorption characteristics, the set temperature θ ₂₀ of the Stirling refrigerator _20, and the temperature θ ₂₈ of the cooling stage 28. The target temperature θ _T is a target temperature given to the actual temperature θ _A detected by the temperature detector 54 on the lower surface side of the pedestal 44 in the sample chamber 42. Heat is sucked from the pedestal portion 44 of the sample chamber 42 by the Stirling refrigerator 20, while heat is supplied from the heat input portion 64. When the supply of heat from the heat input section 64 is zero, the pedestal section 44 of the sample chamber 42 has the lowest temperature, and the temperature at that time is the set temperature θ ₂₀ of the Stirling refrigerator 20.

In other words, the target temperature θ _T for the lower surface side of the pedestal portion 44 is higher than the set temperature θ ₂₀ of the Stirling refrigerator 20. As an example, it has a temperature difference of 2 to 7K.

Hereinafter, a case where the target temperature θ _T is lowered from the upper limit to 77.35K and the set temperature θ ₂₀ of the Stirling refrigerator 20 is set to 75K will be described. The setting of the target temperature θ _T and the set temperature θ ₂₀ of the Stirling refrigerator 20 is executed by the target temperature setting process procedure of the control unit 100.

As described above, when the Stirling refrigerator 20 is operated at the set temperature θ ₂₀ of 75K, the temperature θ ₂₈ of the cooling stage 28 fluctuates somewhat due to the intermittent operation of the cylinder portion 26 or the like. For example, it varies ± 1K. In FIG. 2B, the target temperature θ _T = 77.35K, the set temperature θ ₂₀ = 75K of the Stirling refrigerator 20 and the temperature θ 28 of the cooling stage ₂₈ = (75K ± 1K) are shown.

FIG. 2C is a diagram illustrating a temporal change in the heat input amount Q ₆₄ of the heat input unit 64 when the temperature adjustment is executed according to the temperature adjustment processing procedure of the control unit 100. Since adsorption is not performed from time t ₀ to time t _1, control is performed so that the actual temperature θ _A detected by the temperature detection unit 54 on the lower surface side of the pedestal 44 in the sample chamber 42 is the target temperature θ _T. The Here, since the temperature θ ₂₈ of the cooling stage 28 fluctuates by (75K ± 1K), heat is input from the heat input section 64 in this state, and the actual temperature θ _{A is changed} to θ _T = 77.35K ± 0K. And Therefore, the heat input amount Q ₆₄ is a heat amount for raising the temperature from 75K to 77.35K. In FIG. 2C, the state is shown by using the temperature θ ₆₄ corresponding to Q ₆₄ .

After time t ₁ , there is heat generation due to adsorption, so the heat input amount Q ₆₄ from the heat input section 64 is decreased accordingly. Thereby, the increase in the heat of adsorption can be filled with the decrease in the heat input Q ₆₄ . In FIG. 2C, the amount of decrease in the heat input Q ₆₄ that covers the increase in the heat of adsorption is indicated by ΔQ. The variation (± 1K) of the cooling stage 28 is relaxed by the heat transfer buffer 60. The calculation of the adsorption heat is performed by executing the adsorption heat calculation processing procedure of the control unit 100.

FIG. 2D is a diagram showing a variation in the actual temperature θ _A detected by the temperature detection unit 54 on the lower surface side of the pedestal 44 of the sample chamber 42 after the temperature adjustment is performed. The actual temperature θ _A varies before and after the target temperature θ _T , and the amount of variation can be defined by the feedback gain of the temperature adjustment processing procedure of the control unit 100. As an example, it is considered possible to control the temperature fluctuation of the Stirling refrigerator 20 to about (1/1000). In that case, the target temperature θ _T is set in (1/1000) K units. Can also follow.

In the above, since the performs adsorption heat calculation, the settable range of the target temperature theta _T is narrowed than the settable range of the set temperature theta ₂₀ of the Stirling refrigerating machine 20. When not performing the adsorption heat calculation is settable range of the target temperature theta _T is at the set temperature theta ₂₀ range from the setting range and the same 50K of room temperature of the Stirling refrigerating machine 20 can be set arbitrarily. In addition, the target temperature θ _T can be continuously changed over time within the range.

  DESCRIPTION OF SYMBOLS 10 Adsorption characteristic measuring apparatus, 20 Stirling refrigerator, 22 External compressor, 24 External expander, 26 Cylinder part, 28 Cooling stage, 30 Main body part, 32 Vacuum heat insulation chamber, 34 Upper container, 36 Lower container, 38 Clamp , 40 Vacuum pump, 42 Sample chamber, 44 pedestal part, 46 Lid part, 48 Storage space, 50 Sample stage, 52, 54 Temperature detection part, 60 Heat transfer buffer, 62 Tube part, 64 Heat input part, 66 Cap part, 68 Heat transfer member, 70 Thermal anchor, 74 Adsorbate supply unit, 76 Discharge unit, 80 Piping unit, 82 Manifold, 86, 90, Pressure gauge, 88, 92, 94 On-off valve, 100 Control unit, 102 Target temperature setting process Procedure, 104 Temperature adjustment processing procedure, 106 Adsorption characteristic calculation processing procedure, 108 Adsorption heat calculation processing procedure, 110 Output unit.

Claims (4)

A sample chamber connected to at least the adsorbate supply unit, containing a sample, and having a predetermined high heat conductivity;
A regenerative cooling means having a cooling stage for cooling the sample and capable of electrical control;
A heat transfer buffer provided between the sample chamber and the cooling stage, having a predetermined heat capacity and a predetermined high heat transfer property;
A heat input section that is provided between the heat transfer buffer and the sample chamber and receives heat into the sample chamber;
A temperature adjusting means for controlling the amount of heat input so that the deviation between the set target adsorption measurement temperature and the temperature of the sample chamber becomes zero; and
A measuring means for measuring the adsorption characteristics of the sample under the target adsorption measuring temperature;
Based on the heat input amount of the heat input part during the adsorption characteristic measurement, an adsorption heat calculation part for obtaining heat of adsorption when the adsorbate is adsorbed to the sample
An adsorption characteristic measuring device comprising: In the adsorption characteristic measuring device according to claim 1,
An adsorption characteristic measuring apparatus comprising a vacuum heat insulation chamber that houses a sample chamber, a heat input section, a heat transfer buffer, and a cooling stage. In the adsorption characteristic measuring device according to claim 2,
The temperature adjustment means sets the target adsorption measurement temperature in units of (1/1000) K. In the adsorption | suction characteristic measuring apparatus of any one of Claim 1 to 3,
Regenerative cooling means
An adsorption characteristic measuring apparatus, which is a Stirling refrigerator or a GM refrigerator.

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