Cold storage materials, cold storage material particles, cold storage devices, refrigerators, cryopumps, superconducting magnets, nuclear magnetic resonance imaging devices, nuclear magnetic resonance devices, magnetic field applied single crystal pulling devices, and helium recondensation devices.

Abstract

To provide a cold storage material having excellent specific heat characteristics.SOLUTION: A cold storage material of an embodiment includes: a SmNiGe3-type crystal phase; and holmium (Ho), erbium (Er), nickel (Ni), and silicon (Si) and / or germanium (Ge).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Embodiments of the present invention relate to a thermal storage material, thermal storage material particles, a thermal storage device, a refrigerator, a cryopump, a superconducting magnet, a nuclear magnetic resonance imaging device, a nuclear magnetic resonance device, a magnetic field applied single crystal pulling device, and a helium recondensation device. [Background technology]

[0002] In recent years, superconductivity technology has advanced remarkably, and as its application fields expand, the development of small, high-performance cryogenic refrigerators has become essential. Cryogenic refrigerators are required to be lightweight, compact, and highly thermally efficient. Cryogenic refrigerators are being put into practical use in a variety of application fields.

[0003] A cryogenic refrigerator is equipped with a regenerator filled with multiple cold storage materials. For example, cold is generated by heat exchange between the cold storage materials and helium gas passing through the regenerator.

[0004] One example of a thermal storage material is a magnetic thermal storage material containing rare earth elements and metals. An example of a magnetic thermal storage material containing rare earth elements and metals is HoCu2. To improve the performance of cryogenic refrigerators, the realization of thermal storage materials with excellent specific heat properties is expected. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2022 / 224783 [Non-patent literature]

[0006] [Non-Patent Document 1] Fabiana R. Arantes et al., “Structure, magnetism, and transport of single-crystalline RNiSi3(R=Y,Gd-Tm,Lu)”, Physical Review Materials 2,044402(2018) [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The problem that this invention aims to solve is to provide a cold storage material with excellent specific heat properties. [Means for solving the problem]

[0008] The refrigerant material of the embodiment contains a SmNiGe3 type crystalline phase and includes holmium (Ho), erbium (Er), nickel (Ni), silicon (Si), and / or germanium (Ge). [Brief explanation of the drawing]

[0009] [Figure 1] A schematic cross-sectional view of the cold storage material according to the first embodiment. [Figure 2] A diagram showing an example of the specific heat characteristics of the thermal storage material of the first embodiment. [Figure 3] A schematic cross-sectional view showing the main components of the refrigerator according to the fourth embodiment. [Figure 4] A cross-sectional view showing the schematic configuration of the cryopump of the fifth embodiment. [Figure 5] A perspective view showing the schematic configuration of a superconducting magnet according to the sixth embodiment. [Figure 6] A cross-sectional view showing the schematic configuration of the nuclear magnetic resonance imaging apparatus according to the seventh embodiment. [Figure 7] A cross-sectional view showing the schematic configuration of a nuclear magnetic resonance apparatus according to the eighth embodiment. [Figure 8] A perspective view showing the schematic configuration of a magnetic field applied single crystal pulling apparatus according to the ninth embodiment. [Figure 9] A schematic diagram showing the general configuration of the helium recondenser according to the tenth embodiment.

Best Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same or similar members etc. are denoted by the same reference numerals, and the description of the members etc. that have been described once may be omitted as appropriate. <​​​​​​​​​​​​​​​​​​​​​

[0016] Whether or not the thermal storage material 100 contains a SmNiGe3-type crystalline phase can be determined by powder X-ray diffraction (XRD). Furthermore, whether or not the SmNiGe3-type crystalline phase is the dominant crystalline phase among the crystalline phases contained in the thermal storage material 100 can be determined, for example, by comparing the peak intensities of the crystalline phases obtained by powder X-ray diffraction. Additionally, by analyzing the weight ratio of the crystalline phases present in the sample by performing Rietveld analysis on the diffraction pattern obtained by the XRD method, and comparing the obtained values, it can be determined whether or not the SmNiGe3-type crystalline phase is the dominant crystalline phase.

[0017] Furthermore, whether or not the SmNiGe3 type crystal phase is the dominant crystal phase in the refrigerant material 100 can be determined, for example, by observing a backscattered electron image of a cross-section of the refrigerant material 100 using a scanning electron microscope (SEM). For example, this can be determined by comparing the occupied area of ​​crystal grains 10 identified as the SmNiGe3 type crystal phase in the backscattered electron image with the occupied area of ​​other crystal grains 10 using image processing software. Whether or not a crystal grain 10 is the SmNiGe3 type crystal phase can be determined, for example, by energy-dispersive X-ray spectroscopy (EDX).

[0018] The refrigerant material 100 contains holmium (Ho), erbium (Er), nickel (Ni), silicon (Si), and / or germanium (Ge). For example, the crystal grain 10 contains holmium (Ho), erbium (Er), nickel (Ni), silicon (Si), and / or germanium (Ge).

[0019] The chemical composition of the SmNiGe3-type crystalline phase contained in the thermal storage material 100 is, for example, (Ho 1-x W x ) 1±z Ni 1±z (Si y Ge 1-y ) 3±zIt can be expressed as follows. In the above compositional formula, x is greater than 0 and less than 1 (0 < X < 1). Also, in the above compositional formula, y is 0 or more and 1 or less (0 ≦ y ≦ 1). Further, in the above compositional formula, z is 0 or more and 0.1 or less (0 ≦ z ≦ 0.1).

[0020] The cold storage material 100 includes, for example, a solid solution in which Ho or Er is present at the Sm atomic position of the SmNiGe3-type crystal.

[0021] The sum of the atomic concentrations of holmium (Ho) and erbium (Er) contained in the cold storage material 100 is, for example, 15 atomic % or more and 25 atomic % or less. Also, the atomic concentration of nickel (Ni) contained in the cold storage material 100 is, for example, 15 atomic % or more and 25 atomic % or less. Further, the total of the atomic concentrations of silicon (Si) and germanium (Ge) contained in the cold storage material 100 is, for example, 50 atomic % or more and 70 atomic % or less.

[0022] The atomic concentration of holmium (Ho) contained in the cold storage material 100 is preferably, for example, greater than the atomic concentration of erbium (Er) contained in the cold storage material 100.

[0023] The sum of the atomic concentrations of holmium (Ho) and erbium (Er) contained in the crystal grain 10 is, for example, 15 atomic % or more and 25 atomic % or less. Also, the atomic concentration of nickel (Ni) contained in the crystal grain 10 is, for example, 15 atomic % or more and 25 atomic % or less. Further, the total of the atomic concentrations of silicon (Si) and germanium (Ge) contained in the crystal grain 10 is, for example, 50 atomic % or more and 70 atomic % or less.

[0024] The atomic concentration of holmium (Ho) contained in the crystal grain 10 is preferably, for example, greater than the atomic concentration of erbium (Er) contained in the crystal grain 10.

[0025] Detection of elements contained in the cold storage material 100 and measurement of the atomic concentration of the elements can be achieved, for example, by using inductively coupled plasma atomic emission spectroscopy (ICP - AES). For example, the cold storage material 100 is dissolved in a liquid, and the dissolved cold storage material 100 is measured by inductively coupled plasma atomic emission spectroscopy.

[0026] Detection of elements contained in the cold storage material 100 or the crystal grains 10 and measurement of the atomic concentration of the elements can be achieved, for example, by using energy - dispersive X - ray spectroscopy (EDX) or wavelength - dispersive X - ray analysis (WDX).

[0027] Assume that the peak temperature of the volumetric specific heat of HoNiSi3 in the temperature range below 20K is T1 (K), and the peak temperature of the volumetric specific heat of ErNiSi3 is T2 (K). Let the atomic ratio of erbium (Er) to the sum of the atomic ratios of holmium (Ho) and erbium (Er) in the cold storage material 100 be X (0 < X < 1). In this case, the peak temperature TX (K) of the volumetric specific heat of the cold storage material 100 is, for example, smaller than T1-(T1 - T2)X.

[0028] Similarly, assume that the peak temperature of the volumetric specific heat of HoNiGe3 in the temperature range below 20K is T3 (K), and the peak temperature of the volumetric specific heat of ErNiGe3 is T4 (K). Let the atomic ratio of erbium (Er) to the sum of the atomic ratios of holmium (Ho) and erbium (Er) in the cold storage material 100 be X (0 < X < 1). In this case, the peak temperature TX (K) of the volumetric specific heat of the cold storage material 100 is, for example, smaller than T3-(T3 - T4)X.

[0029] When the peak temperature of the volumetric specific heat of the cold storage material 100 in the temperature range below 20K is TX (K) and the atomic ratio of erbium (Er) to the sum of the atomic ratios of holmium (Ho) and erbium (Er) is X (0 < X < 1), for example, in the (Ho, Er)NiSi3 system, the following inequality holds. TX < - 6.7X + 10.4

[0030] Similarly, the following inequality holds in the (Ho, Er)NiGe3 system. TX < -4.5X + 10.2

[0031] Next, an example of the method for manufacturing the cold storage material of the first embodiment will be described.

[0032] The method for manufacturing the magnetic refrigeration material particles of the first embodiment is not particularly limited, and various manufacturing methods can be applied. For example, it can be manufactured by melting the raw material into a molten metal by a high-frequency melting method or the like and pouring it into a mold. Further, for example, a raw material mixture can be prepared by mixing raw material powders, and the obtained raw material mixture can be manufactured by molding and sintering in a vacuum furnace. Further, the raw material can be made into a molten metal by an arc melting method and cooled on a Cu hearth to manufacture it.

[0033] By the above manufacturing method, the cold storage material 100 of the first embodiment can be manufactured.

[0034] The cold storage material 100 of the first embodiment includes a SmNiGe3-type crystal phase and contains holmium (Ho), erbium (Er), nickel (Ni), silicon (Si) and / or germanium (Ge). The chemical composition of the SmNiGe3-type crystal phase contained in the cold storage material 100 is, for example, (Ho 1-x Er x ) 1±z Ni 1±z (Si y Ge 1-y ) 3±z and can be expressed as. In the above composition formula, x is greater than 0 and less than 1 (0 < X < 1). Further, in the above composition formula, y is 0 or more and 1 or less (0 ≦ y ≦ 1). Further, in the above composition formula, z is 0 or more and 0.1 or less (0 ≦ z ≦ 0.1).

[0035] The cold storage material 100 of the first embodiment can achieve a high volumetric specific heat, for example, as compared with HoCu2.

[0036] In addition, the cold storage material 100 of the first embodiment has a smaller atomic ratio of rare earth elements contained therein, for example, compared to HoCu2. Since the atomic ratio of the expensive rare earth elements is small, the manufacturing cost of the cold storage material 100 can be reduced.

[0037] FIG. 2 is a diagram showing an example of the specific heat characteristics of the cold storage material of the first embodiment. The horizontal axis in FIG. 2 is the amount ratio of holmium (Ho) and erbium (Er) contained in the cold storage material 100, and the vertical axis is the peak temperature of the volume specific heat.

[0038] The peak temperature of the volume specific heat is the temperature at which the distribution of the volume specific heat of the cold storage material shows a peak. The peak temperature of the volume specific heat corresponds to the magnetic transition temperature of the cold storage material.

[0039] As shown in FIG. 2, the cold storage material 100 of the first embodiment can change the peak temperature of the volume specific heat to a desired value by changing the amount ratio of holmium (Ho) and erbium (Er) contained therein. Therefore, for example, by using the cold storage material 100, the design freedom of the refrigerator can be improved.

[0040] FIG. 2 shows the case where the peak temperature T1 of the volume specific heat of HoNiSi3 is 10.4 K and the peak temperature T2 of the volume specific heat of ErNiSi3 is 3.7 K. The cold storage material 100 of the first embodiment can change the peak temperature of the volume specific heat to a desired value between 10.4 K and 3.7 K by changing the amount ratio of holmium (Ho) and erbium (Er) contained therein.

[0041] Assume that the peak temperature of the volume specific heat of HoNiSi3 in the temperature range of 20 K or lower is T1 (K) and the peak temperature of the volume specific heat of ErNiSi3 is T2 (K). And let the atomic ratio of erbium (Er) to the sum of the atomic ratio of holmium (Ho) and the atomic ratio of erbium (Er) in the cold storage material 100 be X (0 < X < 1). In this case, the peak temperature TX (K) of the volume specific heat of the cold storage material 100 is, for example, lower than T1 - (T1 - T2)X.

[0042] As shown in FIG. 2, when the peak temperature of the volume specific heat of the cold storage material 100 in the temperature range of 20 K or lower is TX (K), and the atomic ratio of erbium (Er) to the sum of the atomic ratio of holmium (Ho) and the atomic ratio of erbium (Er) is X (0 < X < 1), the following inequality holds. TX < -6.7X + 10.4

[0043] Since the above inequality holds, by substituting a small amount of erbium (Er) for holmium (Ho), the peak temperature of the volume specific heat of the cold storage material 100 can be significantly reduced from the peak temperature of the volume specific heat of HoNiSi3.

[0044] When the chemical composition is ErNiSi3, the volume specific heat decreases compared with the case where the chemical composition is HoNiSi3. The decrease in the volume specific heat is considered to be proportional to the substitution amount of erbium (Er).

[0045] In the cold storage material 100, by substituting a small amount of erbium (Er) for holmium (Ho), the peak temperature of the volume specific heat can be decreased. Therefore, according to the cold storage material 100, it is considered that the peak temperature of the volume specific heat can be lowered while suppressing the decrease in the volume specific heat.

[0046] In the range where the atomic concentration of holmium (Ho) is larger than the atomic concentration of erbium (Er), that is, when the atomic ratio X of erbium (Er) to the sum of the atomic ratio of holmium (Ho) and the atomic ratio of erbium (Er) is less than 0.5, the change amount of the peak temperature TX of the volume specific heat of the cold storage material 100 with respect to the change in the atomic ratio X is large. Therefore, it is easy to adjust the peak temperature of the volume specific heat of the cold storage material 100. Also, it is considered that the peak temperature of the volume specific heat can be lowered while further suppressing the decrease in the volume specific heat of the cold storage material 100.

[0047] The cold storage material 100 is polycrystalline, and for example, the mechanical strength is improved compared with the case of a single crystal.

[0048] As described above, according to the first embodiment, a cold storage material with excellent specific heat characteristics can be provided.

[0049] (Second embodiment) The thermal storage material particles of the second embodiment are formed from the thermal storage material 100 of the first embodiment. Hereafter, some descriptions that overlap with the first embodiment may be omitted.

[0050] The thermal storage material particles of the second embodiment have a particle size of, for example, 50 μm or more and 3 mm or less. The aspect ratio of the thermal storage material particles is, for example, 1 or more and 5 or less. The aspect ratio of the thermal storage material particles is the ratio of the major axis to the minor axis of the thermal storage material particles. The shape of the thermal storage material particles is, for example, spherical.

[0051] The method for producing magnetic thermal storage particles in the second embodiment is not particularly limited, and various production methods can be applied. For example, a method can be applied in which a molten base alloy of a predetermined composition is rapidly cooled and solidified into particles using a centrifugal spray method, a plasma rotating electrode method, a gas atomization method, a rotating electrode, etc. The base alloy can be produced by the same method as the magnetic thermal storage material production method in the first embodiment.

[0052] As described above, according to the second embodiment, it is possible to provide a cold storage material particle with excellent specific heat properties.

[0053] (Third embodiment) The third embodiment of the cooler is a cooler filled with multiple coolant particles of the second embodiment. For example, in the third embodiment of the cooler, when the perimeter of the projected image of the multiple coolant particles of the second embodiment that are filled is L and the actual area of ​​the projected image is A, the ratio is 4πA / L 2 The proportion of thermal storage material particles with a circularity R of 0.5 or less, as represented by [formula], is 5% or less.

[0054] The circularity R can be determined by image processing of the shapes of multiple refrigerant particles in an image obtained using an optical microscope. Refrigerant particles with a circularity R of 0.5 or less have, for example, surface irregularities.

[0055] For example, if multiple thermal storage material particles containing more than 5% of particles with uneven surfaces are filled into a regenerator, the void ratio inside the regenerator becomes uneven, or the packing becomes unstable. As a result, for example, when the working medium flows in, the thermal storage performance of the regenerator deteriorates.

[0056] Furthermore, for example, stress on the thermal storage material particles during filling or operation of the chiller can cause the particles to move or break down, generating fine particles, which can clog the voids inside the chiller. This clogging of the voids reduces the chilling performance and long-term reliability of the chiller.

[0057] Therefore, it is preferable that the amount of cold storage material particles with a circularity R of 0.5 or less that are filled into the cold storage container be 2% or less, and more preferably 0%.

[0058] As described above, according to the third embodiment, a cooler with excellent properties can be realized by using coolant particles with excellent properties.

[0059] (Fourth embodiment) The fourth embodiment of the refrigerator is a refrigerator equipped with a cooler according to the third embodiment, which is filled with a plurality of the coolant particles of the second embodiment. Hereafter, some descriptions that overlap with the second and third embodiments will be omitted.

[0060] Figure 3 is a schematic cross-sectional view showing the main components of a refrigerator according to the fourth embodiment. Figure 3 is a schematic cross-sectional view showing the main components of a GM refrigerator, which is an example of a refrigerator according to the fourth embodiment. The GM refrigerator, which is an example of a refrigerator according to the fourth embodiment, includes a regenerator according to the third embodiment, which is filled with a plurality of regenerative material particles according to the second embodiment.

[0061] The refrigerator of the fourth embodiment is a two-stage regenerative cryogenic refrigerator 300 used for cooling superconducting equipment and the like. The refrigerator may be, for example, a Stirling type refrigerator or a pulse tube type refrigerator.

[0062] The cryogenic refrigerator 300 (refrigeration unit) comprises a first cylinder 111, a second cylinder 112, a vacuum vessel 113, a first regenerator 114, a second regenerator 115 (regenerator), a first seal ring 116, a second seal ring 117, a first regenerator material 118, a second regenerator material 119 (regenerator material particles), a first expansion chamber 120, a second expansion chamber 121, a first cooling stage 122, a second cooling stage 123, and a compressor 124.

[0063] The cryogenic refrigerator 300 includes a vacuum vessel 113 in which a large-diameter first cylinder 111 and a small-diameter second cylinder 112 coaxially connected to the first cylinder 111 are installed. A first regenerator 114 is arranged in the first cylinder 111 so as to be able to reciprocate. A second regenerator 115, which is an example of a regenerator according to the fourth embodiment, is arranged in the second cylinder 112 so as to be able to reciprocate.

[0064] A first seal ring 116 is positioned between the first cylinder 111 and the first cooler 114. A second seal ring 117 is positioned between the second cylinder 112 and the second cooler 115.

[0065] The first coolant storage container 114 is filled with a first coolant storage material 118, such as a Cu mesh. The second coolant storage container 115 is filled with multiple coolant storage material particles of the second embodiment as a second coolant storage material 119.

[0066] The second cooler 115 may be divided by a metal mesh material and may have multiple packing layers of coolant. When the second cooler 115 is divided into multiple packing layers, at least one packing layer is filled with a group of coolant particles consisting of multiple coolant particles of the second embodiment. This group is then combined with at least one group of coolant particles selected from, for example, a group of rare earth oxide coolant particles, a group of rare earth acid sulfide coolant particles, a group of lead coolant particles, a group of bismuth coolant particles, a group of tin coolant particles, a group of holmium copper coolant particles, a group of erbium nickel coolant particles, a group of erbium cobalt coolant particles, and a group of gadolinium aluminum oxide coolant particles.

[0067] The combination of thermal storage materials shall be such that the group with the highest specific heat peak temperature is designated as the first group of thermal storage material particles, the group with the lowest specific heat peak temperature is designated as the second group of thermal storage material particles, and the combinations shall be made so that the peak specific heat temperatures progressively decrease.

[0068] The first cooler 114 and the second cooler 115 each have passages for a working medium provided in the gaps between the first coolant 118 and the second coolant 119, respectively. The working medium is helium gas.

[0069] A first expansion chamber 120 is provided between the first regenerator 114 and the second regenerator 115. A second expansion chamber 121 is provided between the second regenerator 115 and the tip wall of the second cylinder 112. A first cooling stage 122 is provided at the bottom of the first expansion chamber 120. A second cooling stage 123, which is colder than the first cooling stage 122, is formed at the bottom of the second expansion chamber 121.

[0070] The two-stage cryogenic refrigerator 300 described above is supplied with a high-pressure working medium from a compressor 124. The supplied working medium passes through the first cold storage material 118 filled in the first cold storage chamber 114 and reaches the first expansion chamber 120. Then it passes through the second cold storage material 119 filled in the second cold storage chamber 115 and reaches the second expansion chamber 121.

[0071] During this process, the working medium is cooled by supplying thermal energy to the first and second cold storage materials 118 and 119. The working medium that has passed between the first and second cold storage materials 118 and 119 expands in the first and second expansion chambers 120 and 121, generating cold. Then, the first cooling stage 122 and the second cooling stage 123 are cooled.

[0072] The expanded working medium flows in opposite directions between the first and second thermal storage materials 118 and 119. The working medium is discharged after receiving thermal energy from the first and second thermal storage materials 118 and 119. The regenerative cryogenic refrigerator 300 is configured such that as the regeneration effect improves during this process, the thermal efficiency of the working medium cycle improves, and even lower temperatures can be achieved.

[0073] The regenerator of the cryogenic refrigerator 300 of the fourth embodiment is a second regenerator 115, in which a plurality of the regenerator particles of the second embodiment are filled as the second regenerator material 119. At least a portion of the second regenerator material 119 is the regenerator particles of the second embodiment.

[0074] In the second embodiment, the multiple thermal storage material particles have a ratio of 4πA / L, where L is the perimeter of the projection image of each thermal storage material particle and A is the actual area of ​​the projection image. 2 Preferably, the percentage of materials with a circularity R of 0.5 or less is 5% or less.

[0075] To improve the cooling capacity of a refrigerator, it is desirable to improve the specific heat per unit volume of the thermal storage material, as well as its thermal conductivity and heat transfer coefficient. The thermal storage cryogenic refrigerator 300 of the fourth embodiment comprises a thermal storage material or thermal storage material particles that maintain the volumetric specific heat while improving thermal conductivity and heat transfer coefficient. The thermal storage cryogenic refrigerator 300 of the fourth embodiment comprises a thermal storage material or thermal storage material particles that can reduce manufacturing costs.

[0076] The cryogenic refrigerator 300 of the fourth embodiment includes the cryogenic material particles of the second embodiment, which can change the peak temperature of the volumetric specific heat to a desired value. Therefore, the design flexibility of the refrigerator is improved.

[0077] For example, by using the regenerative cryogenic refrigerator 300 of the fourth embodiment in a magnetic levitation train, the long-term reliability of the magnetic levitation train can be improved.

[0078] As described above, according to the fourth embodiment, a refrigerator with excellent properties can be realized by using thermal storage material particles with excellent properties.

[0079] (Fifth embodiment) The cryopump of the fifth embodiment is equipped with the refrigerator of the fourth embodiment. Some descriptions that overlap with the fourth embodiment will be omitted below.

[0080] Figure 4 is a cross-sectional view showing the schematic configuration of a cryopump according to the fifth embodiment. The cryopump according to the fifth embodiment is a cryopump 500 equipped with the regenerative cryogenic refrigerator 300 of the fourth embodiment.

[0081] The cryopump 500 includes a cryopanel 501 for condensing or adsorbing gas molecules, a regenerative cryogenic refrigerator 300 for cooling the cryopanel 501 to a predetermined cryogenic temperature, a shield 503 provided between the cryopanel 501 and the regenerative cryogenic refrigerator 300, a baffle 504 provided at the intake port, and a ring 505 for changing the exhaust velocity of argon, nitrogen, hydrogen, etc.

[0082] According to the fifth embodiment, a cryopump with excellent characteristics can be realized by using a refrigerator with excellent characteristics.

[0083] (Sixth embodiment) The superconducting magnet of the sixth embodiment is equipped with the refrigerator of the fourth embodiment. Hereafter, some descriptions that overlap with the fourth embodiment will be omitted.

[0084] Figure 5 is a perspective view showing the schematic configuration of the superconducting magnet of the sixth embodiment. The superconducting magnet of the sixth embodiment is a superconducting magnet 600 for a magnetic levitation train equipped with the regenerative cryogenic refrigerator 300 of the fourth embodiment.

[0085] The superconducting magnet 600 for magnetic levitation trains comprises a superconducting coil 601, a liquid helium tank 602 for cooling the superconducting coil 601, a liquid nitrogen tank 603 to prevent evaporation of liquid helium, laminated insulation material 605, power lead 606, a permanent current switch 607, and a regenerative cryogenic refrigerator 300.

[0086] According to the sixth embodiment, a superconducting magnet with excellent properties can be realized by using a refrigerator with excellent properties.

[0087] (Seventh Embodiment) The nuclear magnetic resonance imaging apparatus of the seventh embodiment is equipped with the refrigerator of the fourth embodiment. Hereafter, some descriptions that overlap with the fourth embodiment will be omitted.

[0088] Figure 6 is a cross-sectional view showing the schematic configuration of a nuclear magnetic resonance imaging apparatus according to the seventh embodiment. The nuclear magnetic resonance imaging (MRI) apparatus of the seventh embodiment is a nuclear magnetic resonance imaging apparatus 700 equipped with a regenerative cryogenic refrigerator 300 according to the fourth embodiment.

[0089] The nuclear magnetic resonance imaging apparatus 700 includes a superconducting static magnetic field coil 701 that applies a spatially uniform and temporally stable static magnetic field to the human body, a correction coil (not shown) that corrects for non-uniformity of the generated magnetic field, a gradient magnetic field coil 702 that provides a magnetic field gradient to the measurement area, a radio wave transmitting and receiving probe 703, a cryostat 705, and a radiative insulating shield 706. A regenerative cryogenic refrigerator 300 is used to cool the superconducting static magnetic field coil 701.

[0090] According to the seventh embodiment, a nuclear magnetic resonance imaging apparatus with excellent characteristics can be realized by using a refrigerator with excellent characteristics.

[0091] (Eighth embodiment) The nuclear magnetic resonance apparatus of the eighth embodiment is equipped with the refrigerator of the fourth embodiment. Hereafter, some descriptions that overlap with the fourth embodiment will be omitted.

[0092] Figure 7 is a cross-sectional view showing the schematic configuration of a nuclear magnetic resonance (NMR) apparatus according to the eighth embodiment. The nuclear magnetic resonance (NMR) apparatus of the eighth embodiment is a nuclear magnetic resonance apparatus 800 equipped with a regenerative cryogenic refrigerator 300 according to the fourth embodiment.

[0093] The nuclear magnetic resonance spectrometer 800 includes a superconducting static magnetic field coil 802 that applies a magnetic field to a sample such as organic matter placed in a sample tube 801, a high-frequency oscillator 803 that applies radio waves to the sample tube 801 in the magnetic field, and an amplifier 804 that amplifies the induced current generated in a coil (not shown) around the sample tube 801. It also includes a regenerative cryogenic refrigerator 300 for cooling the superconducting static magnetic field coil 802.

[0094] According to the eighth embodiment, a nuclear magnetic resonance apparatus with excellent characteristics can be realized by using a refrigerator with excellent characteristics.

[0095] (Ninth embodiment) The magnetic field applied single crystal pulling apparatus of the ninth embodiment is equipped with the refrigerator of the fourth embodiment. Hereafter, some descriptions that overlap with the fourth embodiment will be omitted.

[0096] Figure 8 is a perspective view showing the schematic configuration of a magnetic field applied single crystal pulling apparatus according to the ninth embodiment. The magnetic field applied single crystal pulling apparatus of the ninth embodiment is a magnetic field applied single crystal pulling apparatus 900 equipped with a regenerative cryogenic refrigerator 300 according to the fourth embodiment.

[0097] The magnetic field applied single crystal pulling apparatus 900 comprises a single crystal pulling section 901 having a crucible for melting raw materials, a heater, a single crystal pulling mechanism, etc., a superconducting coil 902 for applying a static magnetic field to the molten raw materials, a lifting mechanism 903 for the single crystal pulling section 901, current leads 905, a heat shield plate 906, and a helium container 907. A regenerative cryogenic refrigerator 300 is used for cooling the superconducting coil 902.

[0098] According to the ninth embodiment, a magnetic field applied single crystal pulling apparatus with excellent characteristics can be realized by using a refrigerator with excellent characteristics.

[0099] (Tenth embodiment) The helium recondenser of the tenth embodiment is equipped with the refrigerator of the fourth embodiment. Hereafter, some descriptions that overlap with the fourth embodiment will be omitted.

[0100] Figure 9 is a schematic diagram showing the general configuration of the helium recondenser according to the tenth embodiment. The helium recondenser according to the tenth embodiment is a helium recondenser 1000 equipped with the regenerative cryogenic refrigerator 300 of the fourth embodiment.

[0101] The helium recondenser 1000 comprises a regenerative cryogenic refrigerator 300, an evaporation pipe 1001, and a liquefaction pipe 1002.

[0102] The helium recondenser 1000 can recondense helium gas evaporating from a liquid helium apparatus to produce liquid helium. The liquid helium apparatus is, for example, a superconducting magnet, a nuclear magnetic resonance (NMR) apparatus, a nuclear magnetic resonance imaging (MRI) apparatus, a physical property measurement system (PPMS), or a magnetic property measurement system.

[0103] Helium gas is introduced from a liquid helium apparatus (not shown) through evaporation pipe 1001 to a helium recondenser 1000. The helium gas is cooled to 4K, below the liquefaction temperature of helium, by a regenerative cryogenic refrigerator 300. The condensed liquid helium returns to the liquid helium apparatus through liquefaction pipe 1002.

[0104] According to the tenth embodiment, a helium recondenser with excellent properties can be realized by using a refrigerator with excellent properties.

[0105] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. For example, components of one embodiment may be replaced or modified with components of another embodiment. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0106] The technical solutions of the present invention will be described below. The following technical solutions are included in the scope of the present invention.

[0107] (Technical Solution 1) Containing a SmNiGe3-type crystal phase, A cold storage material containing holmium (Ho), erbium (Er), nickel (Ni), and silicon (Si) and / or germanium (Ge).

[0108] (Technical Solution 2) The sum of the atomic concentration of holmium (Ho) and the atomic concentration of erbium (Er) is 15 atomic % or more and 25 atomic % or less, The atomic concentration of nickel (Ni) is 15 atomic % or more and 25 atomic % or less, The total of the atomic concentration of silicon (Si) and the atomic concentration of germanium (Ge) is 50 atomic % or more and 70 atomic % or less, the cold storage material according to Technical Solution 1.

[0109] (Technical Solution 3) The cold storage material according to Technical Solution 1 or Technical Solution 2, which is polycrystalline.

[0110] (Technical Solution 4) The cold storage material according to any one of Technical Solutions 1 to 3, wherein the proportion occupied by the SmNiGe3-type crystal phase is larger than the proportion occupied by other crystal phases.

[0111] (Technical Solution 5) The peak temperature of the volumetric specific heat of HoNiSi3 is T1 (K), the peak temperature of the volumetric specific heat of ErNiSi3 is T2 (K), and when the atomic ratio of erbium (Er) to the sum of the atomic ratios of holmium (Ho) and erbium (Er) is X (0 < X < 1), the peak temperature TX (K) of the volumetric specific heat is lower than T1 - (T1 - T2)X, the cold storage material according to any one of Technical Solutions 1 to 4.

[0112] (Technical Solution 6) The peak temperature of the volumetric specific heat of HoNiGe3 is T1 (K), the peak temperature of the volumetric specific heat of ErNiSi3 is T2 (K), and when the atomic ratio of erbium (Er) to the sum of the atomic ratios of holmium (Ho) and erbium (Er) is X (0 < X < 1), the peak temperature TX (K) of the volumetric specific heat is lower than T1 - (T1 - T2)X. The cold storage material described in any one of Technical Solutions 1 to 4.

[0113] (Technical Solution 7) The cold storage material described in any one of Technical Solutions 1 to 6, in which the atomic concentration of holmium (Ho) is greater than the atomic concentration of erbium (Er).

[0114] (Technical Solution 8) Cold storage material particles formed of the cold storage material described in any one of Technical Solutions 1 to 7, with a particle size of 50 μm or more and 3 mm or less.

[0115] (Technical Solution 9) A cold storage device filled with a plurality of the cold storage material particles described in Technical Solution 8.

[0116] (Technical Solution 10) A refrigerator equipped with the cold storage device described in Technical Solution 9.

[0117] (Technical Solution 11) A cryopump equipped with the refrigerator described in Technical Solution 10.

[0118] (Technical Solution 12) A superconducting magnet equipped with the refrigerator described in Technical Solution 10.

[0119] (Technical Solution 13) A nuclear magnetic resonance imaging device equipped with the refrigerator described in Technical Solution 10.

[0120] (Technical Solution 14) A nuclear magnetic resonance device equipped with the refrigerator described in Technical Solution 10.

[0121] (Technical Solution 15) A magnetic field applied single crystal pulling device equipped with the refrigerator described in Technical Solution 10.

[0122] (Technical proposal 16) A helium recondenser equipped with the refrigerator described in Technical Proposal 10. [Explanation of symbols]

[0123] 100 Cold storage material 115 Second regenerator (regenerator) 119 Second cold storage material (cold storage material particles) 200 Granulated particles for cold storage material particles 300 Type Cryogenic Refrigeration Unit (Refrigeration Unit) 500 Cryopump 600 Superconducting Magnets 700 Nuclear Magnetic Resonance Imaging System 800 Nuclear Magnetic Resonance Spectrometer 900 Magnetic field applied single crystal pulling apparatus 1000 Helium Recondenser

Claims

1. SmNiGe ３ It contains a type of crystalline phase, A refrigerant containing holmium (Ho), erbium (Er), nickel (Ni), and silicon (Si) and / or germanium (Ge).

2. The sum of the atomic concentrations of holmium (Ho) and erbium (Er) is between 15 atomic percent and 25 atomic percent. The atomic concentration of nickel (Ni) is between 15 atomic percent and 25 atomic percent. The thermal storage material according to claim 1, wherein the sum of the atomic concentrations of silicon (Si) and germanium (Ge) is 50 atomic percent or more and 70 atomic percent or less.

3. The refrigerant material according to claim 1, wherein it is polycrystalline.

4. SmNiGe ３ The thermal storage material according to claim 1, wherein the proportion of the type crystalline phase is greater than the proportion of other crystalline phases.

5. HoNiSi ３ The peak temperature of the volumetric specific heat is T1 (K), ErNiSi ３ The thermal storage material according to claim 1, wherein the peak temperature of the volumetric specific heat is T2 (K), and when the atomic ratio of erbium (Er) to the sum of the atomic ratios of holmium (Ho) and erbium (Er) is X (0 < X ​​< 1), the peak temperature of the volumetric specific heat TX (K) is less than T1 - (T1 - T2)X.

6. The cold storage material according to claim 1, wherein the peak temperature of the volumetric specific heat of HoNiGe3 is T3 (K), the peak temperature of the volumetric specific heat of ErNiGe3 is T4 (K), and when the atomic ratio of erbium (Er) to the sum of the atomic ratios of holmium (Ho) and erbium (Er) is X (0 < X ​​< 1), the peak temperature of the volumetric specific heat TX (K) is less than T3 - (T3 - T4)X.

7. The cold storage material according to claim 1, wherein the atomic concentration of holmium (Ho) is greater than the atomic concentration of erbium (Er).

8. A cold storage material particle formed from the cold storage material described in claim 1, having a particle size of 50 μm or more and 3 mm or less.

9. A cooler filled with a plurality of the coolant particles described in claim 8.

10. A refrigerator equipped with the coolant storage device described in claim 9.

11. A cryopump comprising the refrigerator described in claim 10.

12. A superconducting magnet equipped with the refrigerator described in claim 10.

13. A nuclear magnetic resonance imaging apparatus comprising the refrigerator described in claim 10.

14. A nuclear magnetic resonance apparatus comprising the refrigerator described in claim 10.

15. A magnetic field applied single crystal pulling apparatus equipped with the refrigerator described in claim 10.

16. A helium recondenser comprising the refrigerator described in claim 10.

Images