The subject disclosure relates to cryogenic environments, and more specifically, to techniques of facilitating low thermal conductivity support systems within cryogenic environments.
A cryostat can maintain samples or devices positioned on a sample mounting surface located within the cryostat at temperatures approaching absolute zero to facilitate evaluating such samples or devices under cryogenic conditions. Cryostats generally provide such low temperatures utilizing five thermal stages that are mechanically coupled to a room temperature plate of an outer vacuum chamber that encloses the five thermal stages. The five thermal stages of a cryostat comprise a thermal profile in which each subsequent thermal stage has a progressively lower temperature than exists at a preceding thermal stage.
Cryostats generally implement support systems that utilize support rods to mechanically couple the thermal stages to the room temperature plate of the outer vacuum chamber and to maintain spatial isolation between adjacent thermal stages. Such support rods can provide a thermal conductivity path that facilitates the propagation of heat from higher temperature thermal stages to lower temperature thermal stages. Various techniques exist break that thermal conductivity path to mitigate the propagation of heat from higher temperature thermal stages to lower temperature thermal stages. For example, some techniques involve introducing holes into a support rod to break a thermal conductivity path provided by the support rod. While such techniques can facilitate mitigating the propagation of heat from higher temperature thermal stages to lower temperature thermal stages, introducing holes into a support rod can reduce a load bearing capacity of the support rod. Accordingly, such techniques may restrict scalability of cryostats.
The following presents a summary to provide a basic understanding of one or more embodiments of the invention. This summary is not intended to identify key or critical elements, or delineate any scope of the particular embodiments or any scope of the claims. Its sole purpose is to present concepts in a simplified form as a prelude to the more detailed description that is presented later. In one or more embodiments described herein, systems, devices, and/or methods that facilitate low thermal conductivity support systems within cryogenic environments are described.
According to an embodiment, a cryostat can comprise a cryostat can comprise a support rod and a washer. The support rod can couple first and second thermal stages of the cryostat. The washer can intervene between the support rod and the first thermal stage. The washer can thermally isolate the support rod and the first thermal stage. One aspect of such a cryostat is that the cryostat can facilitate low thermal conductivity support systems within cryogenic environments.
In an embodiment, a threaded internal wall of the support rod can receive a threaded shaft of an attachment mechanism via the second thermal stage to couple the support rod to the second thermal stage. In an embodiment, a polyimide sleeve can intervene between the threaded shaft of the attachment mechanism and the threaded internal wall of the support rod. One aspect of such a cryostat is that the cryostat can facilitate maintaining an integrity of a coupling between the support rod and the second thermal stage by ensuring the attachment mechanism remains centered within the threaded internal wall of the support rod.
According to another embodiment, a cryostat support system can comprise a tension support rod and a washer. The tension support rod can couple first and second thermal stages of a cryostat. The first and second thermal stages can be coupled to a top plate of an outer vacuum chamber. The washer can intervene between the tension support rod and the second thermal stage. The washer can thermally isolate the tension support rod and the second thermal stage. One aspect of such a cryostat support system is that the system can facilitate low thermal conductivity support systems within cryogenic environments.
In an embodiment, the washer can comprise a first footprint and can be received in a recess formed in the second thermal stage that reduces a thickness of the second thermal stage within a second footprint of the recess that is larger than the first footprint. One aspect of such a cryostat support system is that the system can facilitate preserving a structural integrity of the tension support rod as the geometries of second thermal stage vary due to thermal expansion/contraction.
According to another embodiment, a cryostat support system can comprise a compression support rod and a washer. The compression support rod can couple first and second thermal stages of a cryostat. The first and second thermal stages can be coupled to a bottom plate of an outer vacuum chamber. The washer can intervene between the compression support rod and the first thermal stage. The washer can thermally isolate the compression support rod and the first thermal stage. One aspect of such a cryostat support system is that the system can facilitate low thermal conductivity support systems within cryogenic environments.
In an embodiment, the compression support rod transfers at least a subset of a mechanical load incident on the second thermal stage to the bottom plate. One aspect of such a cryostat support system is that the system can facilitate managing weight/load distribution within a cryostat.
The following detailed description is merely illustrative and is not intended to limit embodiments and/or application or uses of embodiments. Furthermore, there is no intention to be bound by any expressed or implied information presented in the preceding Background or Summary sections, or in the Detailed Description section.
One or more embodiments are now described with reference to the drawings, wherein like referenced numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a more thorough understanding of the one or more embodiments. It is evident, however, in various cases, that the one or more embodiments can be practiced without these specific details.
Each stage among the plurality of stages 140 can be associated with a different temperature. For example, stage 141 can be a 50-kelvin (50-K) stage that is associated with a temperature of 50 kelvin (K), stage 143 can be a 4-kelvin (4-K) stage that is associated with a temperature of 4 K, stage 145 can be associated with a temperature of 700 millikelvin (mK), stage 147 can be associated with a temperature of 100 mK, and stage 149 can be associated with a temperature of 10 mK. In an embodiment, stage 145 can be a Still stage, stage 147 can be a Cold Plate stage, and stage 149 can be a Mixing Chamber stage.
One or more support rods (e.g., support rod 142) can couple the plurality of stages 140 to top plate 114 of outer vacuum chamber 110. Moreover, each stage among the plurality of stages 140 can be spatially isolated from other stages of the plurality of stages 140 by a plurality of support rods (e.g., support rod 144). Some support rods can include multiple sections. For example, support rod 150 includes sections 152, 154, 156, and 158. Section 152 of support rod 150 couples stage 141 to top plate 114 of outer vacuum chamber 110, section 154 couples stage 141 to stage 143, section 156 couples stage 143 to stage 145, and section 158 couples stage 145 to stage 147. In an embodiment, support rods 142, 144, and/or 150 can comprise stainless steel. In an embodiment, support rod 150 can transfer, at least, a subset of mechanical load incident on stages 141, 143, 145, and/or 147 to top plate 114 of outer vacuum chamber 110. For example, section 158 can transfer, at least, a subset of mechanical load incident on stage 147 to top plate 114 via sections 156, 154, and 152. By transferring, at least, a subset of mechanical load incident on stages 141, 143, 145, and/or 147 to top plate 114 of outer vacuum chamber 110, support rod 150 can facilitate managing weight/load distribution within cryostat 100. Gravity acting upon a mass of the plurality of stages 140 can induce a tension force on support rods (e.g., support rod 142) coupling the plurality of stages 140 to top plate 114 or support rods (e.g., support rods 144 and/or 150) spatially isolating those stages 140. Such support rods can be referred to as tension support rods.
As shown by
As discussed above, some support rods can include multiple sections. For example, support rod 180 includes sections 182 and 184. Section 182 of support rod 180 couples plate 160 to bottom plate 116 of outer vacuum chamber 110 and section 184 couples plate 160 to plate 170. In an embodiment, support rods 162, 164, and/or 180 can comprise stainless steel. In an embodiment, support rod 180 can transfer, at least, a subset of mechanical load incident on plates 160 and/or 170 to bottom plate 116 of outer vacuum chamber 110. For example, section 182 can transfer, at least, a subset of mechanical load incident on plate 170 to bottom plate 116 via section 184. By transferring, at least, a subset of mechanical load incident on plates 160 and/or 170 to bottom plate 116 of outer vacuum chamber 110, support rod 180 can facilitate managing weight/load distribution within cryostat 100.
Gravity acting upon a mass of plates 160 and/or 170 can induce a compression force on support rods (e.g., support rod 162) coupling plates 160 and/or 170 to bottom plate 116 or support rods (e.g., support rods 164 and/or 180) spatially isolating those plates. Such support rods can be referred to as compression support rods.
As discussed in greater detail below, a thermal conductivity path between stages of cryostat 100 can be broken using washers comprising material having low thermal conductivity (e.g., a material having a thermal conductivity of less than 1 watt per meter-kelvin (W/mK)). In particular, a washer comprising a low thermal conductivity material (e.g., a polyimide, such as KAPTON or VESPEL that are each available from DuPont de Nemours, Inc., of Wilmington, Delaware) can intervene between a support rod and a stage to break a thermal conductivity path between stages of cryostat 100. In an embodiment, a thermal gradient along a support rod coupling three or more stages can be minimized by thermally coupling the support rod to, at least, one intervening stage within the three or more stages. For example, support rod 150 couples stages 141, 143, 145, and 147 to top plate 114 of outer vacuum chamber 110. In this example, sections 154 and/or 156 of support rod 150 can be thermally coupled to stages 143 and/or 145.
As best seen in
An internal threaded wall (e.g., internal threaded wall 740 of
A threaded internal wall (e.g., threaded internal wall 1012 of
With reference to
One skilled in the art will recognize that geometries of stage 141 can vary as a temperature of stage 141 changes due to thermal expansion/contraction. Receiving each shank washer 330 within a recess of stage 141 having a larger footprint than that shank washer 330 can facilitate preserving a structural integrity of support rod 142 as the geometries of stage 141 vary due to thermal expansion/contraction. For example, the larger footprint of recess 610 can facilitate movement of support rod 142 within recess 610 responsive to such variations in geometry of stage 141 to mitigate structural failure of support rod 142. As another example, the larger footprint of recess 373 can also facilitate movement of support rod 142 within recess 610 responsive to such variations in geometry of stage 141 to mitigate structural failure of support rod 142.
A comparison between shank sections 240 and 1405 illustrates that a number of variations can be made to a shank section to accommodate different cryostat configurations (e.g., spacing between adjacent stages). For example, shank section 240 comprises a length (defined by a length 1014 of body 1010 and a length 1024 of threaded shaft 242) that is less than a length (defined by a length 1414 of body 1410 and a length 1424 of threaded shaft 1420) of shank section 1405. In this example, shank section 240 can facilitate coupling adjacent stages and/or plates of a cryostat that are relatively closely spaced whereas shank section 1405 can facilitate coupling adjacent stages and/or plates of the cryostat that are relatively distantly spaced. As another example, shank section 1405 comprises a ratio between the length 1414 of body 1410 and the length 1424 of threaded shaft 1420 that is larger than a comparable ratio of shank section 240. This distinction illustrates that a ratio between a length of a body and a length of a threaded shaft can be varied for a shank section to accommodate different load bearing requirements.
As another example, channel 1040 extends within the body 1010 of shank section 240 by a length 1120 that positions channel 1040 within tool interface 1030. In contrast, channel 1440 extends within the body 1410 of shank section 1405 by a length 1520 that positions channel 1440 external to tool interface 1430. A comparison between
Embodiments of the present invention may be a system, a method, and/or an apparatus at any possible technical detail level of integration. What has been described above includes mere examples of systems, methods, and apparatus. It is, of course, not possible to describe every conceivable combination of components or computer-implemented methods for purposes of describing this disclosure, but one of ordinary skill in the art can recognize that many further combinations and permutations of this disclosure are possible. Furthermore, to the extent that the terms “includes,” “has,” “possesses,” and the like are used in the detailed description, claims, appendices and drawings such terms are intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.
In addition, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. Moreover, articles “a” and “an” as used in the subject specification and annexed drawings should generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form. As used herein, the terms “example” and/or “exemplary” are utilized to mean serving as an example, instance, or illustration. For the avoidance of doubt, the subject matter disclosed herein is not limited by such examples. In addition, any aspect or design described herein as an “example” and/or “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it meant to preclude equivalent exemplary structures and techniques known to those of ordinary skill in the art.
The descriptions of the various embodiments have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
While certain example embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope the disclosures herein. Thus, nothing in the foregoing description is intended to imply that any particular feature, characteristic, step, module, or block is necessary or indispensable. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the disclosures herein. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of certain of the disclosures herein.
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