Cryogenic cooling apparatus, and method for cryogenically cooling a sample
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Solution Overview
Problem
Dilution refrigerators face challenges in providing high cooling power at low temperatures due to the scarcity and high cost of helium-3, as their cooling power decreases significantly at lower temperatures, requiring large volumes and infrastructure, which is not economically viable for many applications like quantum computing.
Innovation Solution
Incorporating a solid-state microrefrigerator between the sample and the coldest part of the helium circulation system, with a heat receiving end towards the sample and a heat releasing end towards the operating fluid, to enhance cooling efficiency and reduce the need for extensive helium-3 usage by operating the dilution refrigerator at temperatures above absolute lowest achievable base temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a dilution refrigerator is used to cool samples to millikelvin temperatures, then the sample can be cooled to very low temperatures, but the cooling power becomes extremely limited and requires large volumes of expensive helium-3
Solution Approach 1:
The cooling system is divided into two independent stages: a dilution refrigerator for pre-cooling to millikelvin temperatures, and a solid-state microrefrigerator for final cooling to sub-millikelvin temperatures. This segmentation allows each stage to operate in its optimal temperature range, with the microrefrigerator providing high cooling power at the lowest temperatures without requiring additional helium-3.
Solution Approach 2:
The solid-state microrefrigerator acts as an intermediary cooling device between the dilution refrigerator's cold stage and the sample. It receives thermal energy from the sample and transfers it to the dilution refrigerator's cold fluid, enabling efficient heat transfer without direct contact with the helium-3 system.
2Loss of energy
If the dilution refrigerator is operated at the lowest achievable base temperature to maximize cooling efficiency, then cooling efficiency improves, but the cooling power decreases significantly
Solution Approach 1:
The dilution refrigerator operates continuously at its optimal base temperature, maintaining maximum cooling efficiency. The solid-state microrefrigerator operates continuously to provide the additional cooling power needed at lower temperatures, ensuring that the dilution refrigerator always operates at its most efficient point without interruption.
Solution Approach 2:
The solid-state microrefrigerator replicates the cooling function at lower temperatures where the dilution refrigerator's cooling power is insufficient. It effectively creates a copy of the cooling capability in a temperature range where solid-state devices outperform dilution refrigeration.
3Power
If large volumes of helium-3 are used to increase cooling power at low temperatures, then cooling power increases, but the cost and infrastructure requirements become prohibitively high
Solution Approach 1:
The solid-state microrefrigerator uses abundant, inexpensive solid-state materials instead of scarce helium-3. The device can be manufactured using standard solid-state fabrication techniques, making it a cost-effective alternative to expanding helium-3 inventory.
Solution Approach 2:
The invention changes the operating parameters from relying on large volumes of cryogenic fluid (helium-3) to using electrically-driven solid-state cooling. This parameter change from fluid-based to solid-state-based cooling fundamentally alters the resource requirements.
4Power
If a solid-state microrefrigerator is added between the sample and the dilution refrigerator, then cooling power at low temperatures increases, but the device complexity increases
Solution Approach 1:
The solid-state microrefrigerator is thermally integrated with the dilution refrigerator's cold stage, merging the two cooling systems into a unified cryogenic platform. The heat release end of the microrefrigerator transfers thermal energy directly to the cold fluid in the dilution refrigerator, creating a combined system that leverages the strengths of both technologies.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for high cooling power at low temperatures with reduced helium-3 consumption, achieving efficient heat transfer and scalability, thus addressing the cost and resource constraints of traditional dilution refrigeration methods.
Implementation Method 1
at least one solid-state microrefrigerator with a heat receiving end and a heat releasing end... located on a thermal conduction path between said sample attachment and operating fluid... with said heat receiving end towards said sample and said heat releasing end towards said operating fluid
Implementation Method 2
In cryogenic cooling technology, dilution refrigerators are typically used to cool samples to temperatures in the millikelvin range
Implementation Method 3
cooling of samples to temperatures in the millikelvin range
Data Source
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AI summary
A cryogenic cooling apparatus comprises a vessel (101) configured to hold operating fluid (102) during operation and at least one solid-state microrefrigerator (103) with a heat receiving end and a heat releasing end. The cryogenic cooling apparatus comprises a sample attachment (704) configured to receive a sample (104) into mechanical and thermal connection for cooling said sample during operation of the cryogenic cooling apparatus. Said at least one solid-state microrefrigerator (103) is located on a thermal conduction path between said sample attachment and operating fluid (102) held by said vessel (101), with said heat receiving end towards said sample (104) and said heat releasing end towards said operating fluid (102).