Thermalization Solutions
In cryogenics, thermalization is a system-level design challenge rather than a matter of using standard components. RF/microwave signals (e.g., coaxial cables or waveguides) carry heat into cryogenic environments. If the outer conductor of a coaxial cable is not well-thermalized at each temperature stage, it becomes a thermal shortcut, conducting heat to the coldest parts of the system, thus degrading performance and increasing the cryogenic load. The design goal of thermal anchoring is to ensure that the outer conductors of cables in cryogenic systemsโespecially within dilution refrigeratorsโcan be effectively cooled (anchored) to the temperature of each stage. Achieving efficient thermalization typically requires a combination of specially designed cryo-compatible cables, connectors, thermal links/straps, and possibly heat sinks.
Thermalization components can be categorized as:
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External type: Thermal straps are clamped onto the cables from the outside. These straps are essential for conducting heat from components (such as RF cable outer conductors and connectors) to the cold plate inside the cryostat. One end of the strap connects to the cold stage of the refrigerator, while the other clamps onto the cable.
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Integrated type: The cable or connector itself has built-in thermal anchoring. A growing trend among specialized suppliers is to directly integrate thermal management features into cryogenic cable and connector systems. This simplifies assembly and ensures effective thermal anchoring. As the number of qubits and experimental complexity increase, more RF lines are required, making efficient thermal anchoring ever more critical for managing the heat load of dilution refrigerators.
Example Vendors
Most of the cable connector vendors introduced in earlier sections (Link) have already begun offering cables with integrated thermalization (thermalized connectors).
| Company (Click for link) |
Country/Region | Component Focus | Key Technologies/Innovations | Remarks |
|---|---|---|---|---|
| Technology Applications, Inc. | USA | Thermal Straps | CuTSยฎ copper straps, graphite straps | Renowned global supplier of cryogenic thermal straps |
| Startup Companies & Products | Product Images (Images from official sites) |
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Technology Applications, Inc.
Thermal Straps |
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Quantum Microwave Thermalized Connector Array |
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โฒ Technology Applications, Inc. offers thermal straps in different materials.
Because 1100 aluminum has roughly one third the density of copper and half the thermal conductivity, there is intrinsically a mass benefit of up to one third less for aluminum compared to copper straps.
This allows for a trade-off between thermal anchoring performance and total mass.
Ref: Technology Applications, Inc.
Originally written in Chinese by the author, these articles are translated into English to invite cross-language resonance.
Peir-Ru Wang