Cold storage material, cold storage particle, cold storage unit, freezer, cryopump, superconducting magnet, nuclear magnetic resonance imaging apparatus, nuclear magnetic resonance apparatus, magnetic field application-type single crystal pulling-out apparatus, and helium recondensing apparatus

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] An embodiment of the present invention relates to a cold storage material, cold storage material particles, a cold storage unit, a refrigerator, a cryopump, a superconducting magnet, a nuclear magnetic resonance imaging apparatus, a nuclear magnetic resonance apparatus, a magnetic field application type single crystal pulling apparatus, and a helium recondensation apparatus. [Background technology]

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

[0003] The cryogenic refrigerator includes a regenerator filled with a plurality of regenerator materials. For example, heat is exchanged between the regenerator materials and helium gas passing through the regenerator to generate cold.

[0004] One example of the cold storage material is a magnetic cold storage material containing rare earth elements and metals. 2 In order to improve the performance of cryogenic refrigerators, it is hoped that a cold storage material with excellent specific heat properties will be developed. [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) Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a regenerator material having excellent specific heat characteristics. [Means for solving the problem]

[0008] The cold storage material of the embodiment is SmNiGe 3 It contains a crystalline phase of the type ZnO, and contains holmium (Ho), erbium (Er), nickel (Ni), silicon (Si) and / or germanium (Ge). [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic cross-sectional view of the cold storage material according to the first embodiment. [Diagram 2] FIG. 4 is a diagram showing an example of specific heat characteristics of a cold storage material according to the first embodiment. [Diagram 3] FIG. 11 is a schematic cross-sectional view showing a configuration of a main part of a refrigerator according to a fourth embodiment. [Figure 4] FIG. 11 is a cross-sectional view showing a schematic configuration of a cryopump according to a fifth embodiment. [Diagram 5] FIG. 13 is a perspective view showing a schematic configuration of a superconducting magnet according to a sixth embodiment. [Figure 6] FIG. 13 is a cross-sectional view showing a schematic configuration of a nuclear magnetic resonance imaging apparatus according to a seventh embodiment. [Figure 7] FIG. 13 is a cross-sectional view showing a schematic configuration of a nuclear magnetic resonance spectrometer according to an eighth embodiment. [Figure 8] FIG. 13 is a perspective view showing a schematic configuration of a magnetic field application type single crystal pulling apparatus according to a ninth embodiment. [Figure 9]FIG. 23 is a schematic diagram showing a schematic configuration of a helium recondensation device according to a tenth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same reference numerals will be used to designate the same or similar components, and the description of components that have already been described may be omitted as appropriate.

[0011] In this specification, the term "extremely low temperature" refers to a temperature range in which the superconducting phenomenon can be utilized industrially in a useful manner, for example, a temperature range of 20K or lower.

[0012] (First embodiment) The cold storage material of the first embodiment is SmNiGe 3 The regenerator material of the first embodiment includes a SmNiGe type crystal phase and contains holmium (Ho), erbium (Er), nickel (Ni), silicon (Si) and / or germanium (Ge). 3 The regenerator material according to the first embodiment includes a crystalline phase, at least one element selected from the group consisting of silicon (Si) and germanium (Ge), holmium (Ho), erbium (Er), and nickel (Ni). The regenerator material according to the first embodiment may include only one of silicon and germanium, or may include both of them.

[0013] 1 is a schematic cross-sectional view of a heat regenerator material according to the first embodiment. The heat regenerator material 100 according to the first embodiment is a magnetic heat regenerator material containing a rare earth element and a metal.

[0014] 1, the regenerator material 100 includes a plurality of crystal grains 10. The regenerator material 100 is polycrystalline.

[0015] The cold storage material 100 is SmNiGe 3 For example, the crystalline phase contained in the regenerator material 100 includes SmNiGe 3 The predominant crystal phase is SmNiGe. 3The type crystal phase is the main crystal phase in SmNiGe 3 This means that the proportion of the crystalline phase in the heat exchange material 100 is greater than the proportion of other crystalline phases. 3 It is a type crystalline phase.

[0016] The cooling material 100 is SmNiGe 3 Whether or not the regenerator material 100 contains a crystalline phase can be determined by powder X-ray diffraction (XRD). 3 Whether or not the type crystal phase is the main crystal phase can be determined, for example, by comparing the peak intensities of the crystal phases obtained by powder X-ray diffraction. In addition, the weight ratio of the crystal phase present in the sample can be analyzed by Rietveld analysis of the diffraction pattern obtained by the XRD method, and the obtained values ​​can be compared to determine whether the type crystal phase is the main crystal phase. 3 It is possible to determine whether the type crystal phase is the main crystal phase.

[0017] In addition, among the crystal phases contained in the regenerator material 100, SmNiGe 3 Whether or not the type crystal phase is the main crystal phase can be determined by observing a backscattered electron image of a cross section of the heat accumulating material 100 with a scanning electron microscope (SEM). 3 The area occupied by the crystal grains 10 identified as the SmNiGe type crystal phase can be determined by comparing the area occupied by the other crystal grains 10 using image processing software. 3 Whether or not the crystal phase is the above-mentioned type crystal phase can be determined by, for example, energy dispersive X-ray spectroscopy (EDX).

[0018] The heat storage material 100 includes holmium (Ho), erbium (Er), nickel (Ni), silicon (Si), and / or germanium (Ge). For example, the crystal grains 10 include holmium (Ho), erbium (Er), nickel (Ni), silicon (Si), and / or germanium (Ge).

[0019] SmNiGe contained in the cooling material 1003 The chemical composition of the type crystal phase 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 such. In the above composition formula, x is greater than 0 and less than 1 (0 < x < 1). Also, 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).

[0020] The cold storage material 100 includes, for example, a solid solution in which Ho or Er exists at the Sm atomic position of the SmNiGe 3 type crystal.

[0021] The sum of the atomic concentration of holmium (Ho) and the atomic concentration of 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 concentration of silicon (Si) and the atomic concentration of germanium (Ge) contained in the cold storage material 100 is, for example, 50 atomic % or more and 70 atomic % or less.

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

[0023] The sum of the atomic concentration of holmium (Ho) and the atomic concentration of 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 concentration of silicon (Si) and the atomic concentration of 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 grains 10 is preferably, for example, larger than the atomic concentration of erbium (Er) contained in the crystal grains 10.

[0025] Detection of the elements contained in the cold storage material 100 and measurement of the atomic concentration of the elements can be carried out, 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 the elements contained in the cold storage material 100 or the crystal grains 10 and measurement of the atomic concentration of the elements can be carried out, for example, by using energy - dispersive X - ray spectroscopy (EDX) or wavelength - dispersive X - ray analysis (WDX).

[0027] Let the peak temperature of the volumetric specific heat of HoNiSi 3 in the temperature range of 20K or lower be T1 (K), and the peak temperature of the volumetric specific heat of ErNiSi 3 be T2 (K). And 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, lower than T1-(T1 - T2)X.

[0028] Similarly, let the peak temperature of the volumetric specific heat of HoNiGe 3 in the temperature range of 20K or lower be T3 (K), and the peak temperature of the volumetric specific heat of ErNiGe 3 be T4 (K). And 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, lower 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 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), for example, in the (Ho, Er)NiSi 3 system, the following inequality holds. TX < -6.7X + 10.4

[0030] Similarly, in the (Ho, Er)NiGe 3 system, the following inequality holds. TX < -4.5X + 10.2

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

[0032] The manufacturing method of the magnetic cold storage 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 materials into a molten metal by a high-frequency melting method or the like and pouring it into a mold. Also, for example, it can be manufactured by mixing raw material powders to prepare a raw material mixture, shaping the obtained raw material mixture, and sintering it in a vacuum furnace. Also, it can be manufactured by melting the raw materials into a molten metal by an arc melting method and cooling it on a Cu hearth.

[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 contains a SmNiGe 3 type crystal phase and contains holmium (Ho), erbium (Er), nickel (Ni), silicon (Si) and / or germanium (Ge). The chemical composition of the SmNiGe 3 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±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).

[0035] The cold storage material 100 of the first embodiment is, for example, HoCu 2 Compared with [a certain material], a high volumetric specific heat can be achieved.

[0036] Also, the cold storage material 100 of the first embodiment is, for example, HoCu 2 Compared with [a certain material], the atomic ratio of the rare earth elements contained is small. 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 volumetric specific heat.

[0038] The peak temperature of the volumetric specific heat is the temperature at which the distribution of the volumetric specific heat of the cold storage material shows a peak. The peak temperature of the volumetric 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 volumetric specific heat to a desired value by changing the amount ratio of the contained holmium (Ho) and erbium (Er). Therefore, for example, by using the cold storage material 100, the degree of freedom in the design of the refrigerator can be improved.

[0040] FIG. 2 shows the case where the peak temperature T1 of the volumetric specific heat of HoNiSi 3 is 10.4 K and the peak temperature T2 of the volumetric specific heat of ErNiSi 3 is 3.7 K. The cold storage material 100 of the first embodiment can change the peak temperature of the volumetric specific heat to a desired value between 10.4 K and 3.7 K by changing the amount ratio of the contained holmium (Ho) and erbium (Er).

[0041] The peak temperature of the volumetric specific heat of HoNiSi in the temperature range below 20 K 3 is T1 (K), and let the peak temperature of the volumetric specific heat of ErNiSi 3 be T2 (K). Then, 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, lower than T1 - (T1 - T2)X.

[0042] As shown in FIG. 2, when the peak temperature of the volumetric specific heat of the cold storage material 100 in the temperature range below 20 K 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), the following inequality holds. TX < -6.7X + 10.4

[0043] Since the above inequality holds, by replacing a small amount of holmium (Ho) with erbium (Er), the peak temperature of the volumetric specific heat of the cold storage material 100 can be significantly reduced from the peak temperature of the volumetric specific heat of HoNiSi 3

[0044] When the chemical composition is ErNiSi 3 the volumetric specific heat decreases compared to the case when the chemical composition is HoNiSi 3 . The decrease in the volumetric specific heat is considered to be proportional to the substitution amount of erbium (Er).

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

[0046] ​In the range where the atomic concentration of holmium (Ho) is larger than that of erbium (Er), that is, when the atomic ratio X of erbium (Er) to the sum of the atomic ratios of holmium (Ho) and erbium (Er) is less than 0.5, the change in the peak temperature TX of the volumetric 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 volumetric specific heat of the cold storage material 100. It is also considered that the peak temperature of the volumetric specific heat can be lowered while further suppressing the decrease in the volumetric specific heat of the cold storage material 100.

[0047] The cold storage material 100 is polycrystalline, and hence has improved mechanical strength compared to, for example, a single crystal cold storage material.

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

[0049] Second Embodiment The cold storage material particles of the second embodiment are formed of the cold storage material 100 of the first embodiment. Hereinafter, some of the contents that overlap with the first embodiment may be omitted.

[0050] The cold 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 cold storage material particles is, for example, 1 or more and 5 or less. The aspect ratio of the cold storage material particles is the ratio of the major axis to the minor axis of the cold storage material particles. The shape of the cold storage material particles is, for example, spherical.

[0051] The manufacturing method of the magnetic regenerator particles of the second embodiment is not particularly limited, and various manufacturing methods can be applied. For example, a method can be applied in which a molten base alloy of a predetermined composition is rapidly solidified and granulated by centrifugal atomization, plasma rotating electrode method, gas atomization method, rotating electrode method, etc. The base alloy can be manufactured by the same method as the manufacturing method of the magnetic regenerator of the first embodiment.

[0052] As described above, according to the second embodiment, it is possible to provide cold storage material particles having excellent specific heat characteristics.

[0053] (Third embodiment) The cold storage device of the third embodiment is a cold storage device filled with a plurality of cold storage particles of the second embodiment. For example, when the peripheral length of the projected image of the plurality of cold storage particles of the second embodiment is L and the actual area of ​​the projected image is A, the cold storage device of the third embodiment has a ratio of 4πA / L 2 The ratio of the cold storage material particles having a circularity R of 0.5 or less is 5% or less.

[0054] The circularity R can be obtained by image processing of the shapes of a plurality of cold storage material particles in an image obtained using an optical microscope. Cold storage material particles having a circularity R of 0.5 or less have, for example, unevenness on the surface.

[0055] For example, if the cold storage unit is filled with more than 5% of cold storage particles having uneven surfaces, the porosity in the cold storage unit becomes uneven and the filling property becomes unstable. Therefore, for example, when the working medium flows in, the cold storage performance of the cold storage unit decreases.

[0056] In addition, for example, stress applied to the cold storage material particles when the cold storage material particles are filled or when the refrigerator is in operation may cause the cold storage material particles to move or break down, generating fine particles, which may cause the gaps in the cold storage unit to become clogged. The clogging of the gaps reduces the refrigeration performance and long-term reliability of the refrigerator.

[0057] Therefore, the amount of cold accumulator particles with a circularity R of 0.5 or less packed in the cold accumulator is preferably 2% or less, and more preferably 0%.

[0058] As described above, according to the third embodiment, a regenerator with excellent characteristics can be realized by using regenerator material particles with excellent characteristics.

[0059] (Fourth embodiment) The refrigerator of the fourth embodiment is a refrigerator including the cold storage unit of the third embodiment filled with a plurality of cold storage material particles of the second embodiment. Hereinafter, some of the contents overlapping with the second and third embodiments will be omitted.

[0060] Fig. 3 is a schematic cross-sectional view showing the configuration of the main parts of a refrigerator according to a fourth embodiment. Fig. 3 is a schematic cross-sectional view showing the configuration of the main parts of a GM refrigerator, which is an example of the refrigerator according to the fourth embodiment. The GM refrigerator, which is an example of the refrigerator according to the fourth embodiment, includes the cold storage unit according to the third embodiment filled with a plurality of cold storage 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, etc. The refrigerator may be, for example, a Stirling type refrigerator or a pulse tube type refrigerator.

[0062] The cold storage type cryogenic refrigerator 300 (refrigerator) includes a first cylinder 111, a second cylinder 112, a vacuum container 113, a first cold storage unit 114, a second cold storage unit 115 (cold storage units), a first seal ring 116, a second seal ring 117, a first cold storage material 118, a second cold storage material 119 (cold storage 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 cold storage type cryogenic refrigerator 300 includes a vacuum container 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 cold storage unit 114 is arranged in the first cylinder 111 so as to be capable of reciprocating. A second cold storage unit 115, which is an example of the cold storage unit of the fourth embodiment, is arranged in the second cylinder 112 so as to be capable of reciprocating.

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

[0065] The first regenerator 114 is filled with a first regenerator material 118 such as a Cu mesh. The second regenerator 115 is filled with a second regenerator material 119, which is a plurality of regenerator particles of the second embodiment.

[0066] The second regenerator 115 may be divided by a metal mesh material and have a plurality of regenerator packed layers. When the second regenerator 115 is divided into a plurality of packed layers, at least one packed layer is filled with a regenerator particle group consisting of a plurality of the regenerator particles of the second embodiment. Then, for example, the regenerator particle group is combined with at least one type of regenerator particle group selected from rare earth oxide regenerator particle group, rare earth oxysulfide regenerator particle group, lead regenerator particle group, bismuth regenerator particle group, tin regenerator particle group, holmium copper regenerator particle group, erbium nickel regenerator particle group, erbium cobalt regenerator particle group, and gadolinium aluminum oxide regenerator particle group.

[0067] The combination of the heat storage materials is such that the first heat storage material particle group has a higher peak specific heat temperature, and the second heat storage material particle group has a lower peak specific heat temperature, and the combinations are made so that the peak specific heat temperatures decrease sequentially.

[0068] The first regenerator 114 and the second regenerator 115 each have a passage for the working medium provided in the gap of the first regenerator material 118 and the second regenerator material 119. The working medium is helium gas.

[0069] A first expansion chamber 120 is provided between the first cold storage unit 114 and the second cold storage unit 115. A second expansion chamber 121 is provided between the second cold storage unit 115 and the end 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 has a lower temperature than the first cooling stage 122, is formed at the bottom of the second expansion chamber 121.

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

[0071] At this time, the working medium is cooled by supplying thermal energy to the first cold storage material 118 and the second cold storage material 119. The working medium passing between the first cold storage material 118 and the second cold storage material 119 expands in the first expansion chamber 120 and the second expansion chamber 121 to generate cold. Then, the first cooling stage 122 and the second cooling stage 123 are cooled.

[0072] The expanded working medium flows in the opposite direction between the first cold storage material 118 and the second cold storage material 119. The working medium is discharged after receiving thermal energy from the first cold storage material 118 and the second cold storage material 119. In this process, the heat recovery effect is improved, and the thermal efficiency of the working medium cycle is improved, so that the cold storage type cryogenic refrigerator 300 is configured to realize a lower temperature.

[0073] The cold storage unit included in the cold storage type cryogenic refrigerator 300 of the fourth embodiment fills the second cold storage unit 115 with a plurality of cold storage particles of the second embodiment as the second cold storage material 119. At least a part of the second cold storage material 119 is the cold storage particle of the second embodiment.

[0074] In the second embodiment, when the peripheral length of each projected image of the plurality of cold storage material particles is L and the actual area of ​​the projected image is A, the ratio of the peripheral length of the projected image to the actual area of ​​the plurality of cold storage material particles is 4πA / L 2 It is preferable that the circularity R of 0.5 or less is 5% or less.

[0075] In order to improve the refrigeration capacity of a refrigerator, it is desirable to improve the specific heat per unit volume of the regenerator material and to improve the thermal conductivity and heat transfer coefficient. The regenerator type cryogenic refrigerator 300 of the fourth embodiment is equipped with a regenerator material or regenerator material particles that maintain the volumetric specific heat and improve the thermal conductivity and heat transfer coefficient. The regenerator type cryogenic refrigerator 300 of the fourth embodiment is equipped with a regenerator material or regenerator material particles that can reduce manufacturing costs.

[0076] The regenerative cryogenic refrigerator 300 of the fourth embodiment includes the regenerator particles of the second embodiment that can change the peak temperature of the volumetric specific heat to a desired value, thereby improving the design freedom of the refrigerator.

[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 characteristics can be realized by using the cold storage material particles with excellent characteristics.

[0079] Fifth embodiment The cryopump of the fifth embodiment includes the refrigerator of the fourth embodiment. Hereinafter, some of the contents that overlap with the fourth embodiment will be omitted.

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

[0081] The cryopump 500 includes a cryopanel 501 that condenses or adsorbs gas molecules, a regenerative cryogenic refrigerator 300 that cools 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 that changes the pumping speed 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 includes the refrigerator of the fourth embodiment. Hereinafter, some of the contents that overlap with the fourth embodiment will be omitted.

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

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

[0086] According to the sixth embodiment, a refrigerator with excellent characteristics is used, thereby making it possible to realize a superconducting magnet with excellent characteristics.

[0087] Seventh embodiment The nuclear magnetic resonance imaging apparatus of the seventh embodiment includes the refrigerator of the fourth embodiment. Hereinafter, some of the contents that overlap with the fourth embodiment will be omitted.

[0088] 6 is a cross-sectional view showing a schematic configuration of a nuclear magnetic resonance imaging apparatus according to the seventh embodiment. The nuclear magnetic resonance imaging (MRI) apparatus according to the seventh embodiment is a nuclear magnetic resonance imaging apparatus 700 including the 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 non-uniformity of the generated magnetic field, a gradient magnetic field coil 702 that applies a magnetic field gradient to a measurement region, a radio frequency wave transmitting / receiving probe 703, a cryostat 705, and a radiation heat insulating shield 706. A regenerative type 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 includes the refrigerator of the fourth embodiment. Hereinafter, some of the contents that overlap with the fourth embodiment will be omitted.

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

[0093] The nuclear magnetic resonance apparatus 800 includes a superconducting static magnetic field coil 802 that applies a magnetic field to a sample such as an organic substance 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 an induced current generated in a coil (not shown) around the sample tube 801. The apparatus also includes a regenerative type cryogenic refrigerator 300 that cools 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 application type single crystal pulling apparatus of the ninth embodiment includes the refrigerator of the fourth embodiment. In the following, some of the contents that overlap with the fourth embodiment will be omitted.

[0096] 8 is a perspective view showing a schematic configuration of a magnetic field application type single crystal pulling apparatus of the ninth embodiment. The magnetic field application type single crystal pulling apparatus of the ninth embodiment is a magnetic field application type single crystal pulling apparatus 900 including the regenerative cryogenic refrigerator 300 of the fourth embodiment.

[0097] The magnetic field application type single crystal pulling apparatus 900 includes a single crystal pulling section 901 having a crucible for melting raw material, a heater, a single crystal pulling mechanism, etc., a superconducting coil 902 for applying a static magnetic field to the raw material melt, a lifting mechanism 903 for the single crystal pulling section 901, a current lead 905, a heat shield plate 906, and a helium container 907. A regenerative type cryogenic refrigerator 300 is used to cool the superconducting coil 902.

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

[0099] (Tenth embodiment) The helium recondensing device of the tenth embodiment includes the refrigerator of the fourth embodiment. Hereinafter, some of the contents that overlap with the fourth embodiment will be omitted.

[0100] 9 is a schematic diagram showing a schematic configuration of a helium recondensation apparatus according to the tenth embodiment. The helium recondensation apparatus according to the tenth embodiment is a helium recondensation apparatus 1000 including the regenerative cryogenic refrigerator 300 according to the fourth embodiment.

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

[0102] The helium recondensing device 1000 can recondense helium gas evaporated from a liquid helium device to form liquid helium. The liquid helium device can be, for example, a superconducting magnet, a nuclear magnetic resonance (NMR) device, a nuclear magnetic resonance imaging (MRI) device, a physical property measurement system (PPMS), or a magnetic property measurement system.

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

[0104] According to the tenth embodiment, a refrigerator with excellent characteristics is used, thereby making it possible to realize a helium recondensing device with excellent characteristics.

[0105] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various 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 changed with components of another embodiment. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims.

[0106] The technical solutions of the present invention are described below, and are included in the scope of the present invention.

[0107] (Technical proposal 1) SmNiGe 3 containing a type crystalline phase, A regenerator material including Holmium (Ho), Erbium (Er), Nickel (Ni), Silicon (Si) and / or Germanium (Ge).

[0108] (Technical proposal 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 heat storage material according to Technical Proposal 1, in which the sum of the atomic concentration of silicon (Si) and the atomic concentration of germanium (Ge) is 50 atomic % or more and 70 atomic % or less.

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

[0110] (Technical proposal 4) SmNiGe 3 A heat storage material according to any one of Technical Schemes 1 to 3, in which the proportion of the type crystal phase is greater than the proportions of other crystal phases.

[0111] (Technical proposal 5) HoNiSi 3The peak temperature of the volumetric specific heat is T1 (K), and for ErNiSi 3 The peak temperature of the volumetric specific heat is T2 (K). 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 lower than T1 - (T1 - T2)X. The cold storage material described in any one of Technical Solutions 1 to 4.

[0112] (Technical Solution 6) HoNiGe 3 The peak temperature of the volumetric specific heat is T1 (K), and for ErNiSi 3 The peak temperature of the volumetric specific heat is T2 (K). 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 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 atomic concentration of holmium (Ho) is higher than that of erbium (Er). The cold storage material described in any one of Technical Solutions 1 to 6.

[0114] (Technical Solution 8) Cold storage material particles formed from 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 proposal 13) A nuclear magnetic resonance imaging device equipped with a refrigerator described in Technical Proposal 10.

[0120] (Technical proposal 14) A nuclear magnetic resonance apparatus equipped with a refrigerator described in Technical Proposal 10.

[0121] (Technical proposal 15) A magnetic field application type single crystal pulling apparatus equipped with the refrigerator described in Technical Proposal 10.

[0122] (Technical proposal 16) A helium recondensing device equipped with a 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 Regenerative cryogenic refrigerator (refrigerator) 500 Cryopump 600 Superconducting Magnet 700 Nuclear Magnetic Resonance Imaging Device 800 Nuclear Magnetic Resonance Spectrometer 900 Magnetic Field Application Type Single Crystal Pulling Apparatus 1000 Helium Recondenser

Claims

1. SmNiGe ３ containing a type crystalline phase, A regenerator material including holmium (Ho), erbium (Er), nickel (Ni), silicon (Si) and / or germanium (Ge).

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, 2. The regenerator material according to claim 1, wherein the sum of the atomic concentration of silicon (Si) and the atomic concentration of germanium (Ge) is 50 atomic % or more and 70 atomic % or less.

3. 2. The regenerator material according to claim 1, which is polycrystalline.

4. SmNiGe ３ 2. The regenerator material according to claim 1, wherein the proportion of the type crystal phase is greater than the proportions of other crystal phases.

5. HoNiSi ３ The peak temperature of the volumetric specific heat is T1 (K), ErNiSi ３ The volumetric specific heat peak temperature is T2 (K), and when 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 volumetric specific heat peak temperature TX (K) is smaller than T1-(T1-T2)X.

6. The peak temperature of volumetric heat capacity of HoNiGe3 is T3 (K), the peak temperature of volumetric heat capacity of ErNiGe3 is T4 (K), and when the atomic ratio of erbium (Er) to the sum of atomic ratio of holmium (Ho) and atomic ratio of erbium (Er) is X (0<X<1), the peak temperature TX (K) of volumetric heat capacity is smaller than T3-(T3-T4)X.

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

8. 2. A cold storage material particle formed from the cold storage material according to claim 1, the particle size of which is 50 μm or more and 3 mm or less.

9. A regenerator filled with a plurality of the regenerator particles according to claim 8.

10. A refrigerator comprising the regenerator according to claim 9.

11. A cryopump comprising the refrigerator according to claim 10.

12. A superconducting magnet comprising the refrigerator according to claim 10.

13. A nuclear magnetic resonance imaging apparatus comprising the refrigerator according to claim 10.

14. A nuclear magnetic resonance apparatus comprising the refrigerator according to claim 10.

15. A magnetic field application type single crystal pulling apparatus comprising the refrigerator according to claim 10.

16. A helium recondensing device comprising the refrigerator according to claim 10.

Images