Cryogenically cooled vacuum chamber radiation shields for ultra-low temperature experiments and extreme high vacuum (XHV) conditions
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Solution Overview
Problem
Current ultra-high and extreme-high vacuum systems face challenges in maintaining low temperatures and achieving true XHV pressures due to residual gas particles and thermal radiation, which limits the longevity and effectiveness of experiments.
Innovation Solution
The implementation of a cryogenically cooled vacuum chamber with multiple overlapping radiation shields, thermally isolated from the cooling elements, to reduce thermal radiation and enhance pumping speed by increasing the effective surface area for gas removal, using closed-cycle refrigerators to cool the shields to sub-4K temperatures and sorbent materials to minimize gas saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If radiation shields are cooled to reduce thermal radiation, then thermal radiation load is reduced, but the complexity of the cooling system increases
Solution Approach 1:
The radiation shielding system is divided into multiple discrete shields (first radiation shield, second radiation shield, third radiation shield) that can be independently cooled by separate cooling elements. This segmentation allows each shield to be optimized independently and reduces the complexity of cooling the entire system as a single unit.
Solution Approach 2:
The radiation shields are arranged in a nested configuration where the first radiation shield surrounds the second radiation shield, which in turn surrounds the third radiation shield. This nested arrangement maximizes the shielding effectiveness while minimizing the overall volume and complexity of the cooling system required.
2Object-affected harmful factors
If multiple overlapping radiation shields are added to reduce thermal radiation, then thermal radiation protection is improved, but the device complexity increases
Solution Approach 1:
Each radiation shield is positioned at specific locations within the vacuum chamber to provide targeted thermal radiation protection. The shields are strategically placed to block radiation paths from warm chamber walls to the cryogenic experiment region, providing local quality enhancement where it is most needed.
Solution Approach 2:
The radiation shields extend in multiple dimensions within the vacuum chamber, with each shield having specific longitudinal and radial extents. This multi-dimensional arrangement creates overlapping shielding zones that provide comprehensive thermal radiation protection while allowing for optimized positioning and reduced overall complexity.
3Quantity of substance
If cryopanels are used to remove residual gas, then vacuum pressure is reduced, but gas saturation occurs limiting operational time
Solution Approach 1:
Instead of relying solely on cryopanels that become saturated, the system uses multiple overlapping radiation shields that continuously pump residual gas through cryogenic surfaces. This creates redundant gas removal pathways that extend operational time before regeneration is needed.
Solution Approach 2:
The vacuum system employs a composite approach combining radiation shielding materials with cryogenic cooling capabilities. The radiation shields serve dual functions: blocking thermal radiation and providing continuous gas pumping surfaces, thereby extending operational duration without frequent regeneration.
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 configuration achieves significantly reduced thermal radiation loads, allows for true XHV conditions, and extends the operational time of vacuum systems by minimizing gas saturation and the need for frequent regeneration of cryopanels, thereby improving the longevity and efficiency of experiments.
Implementation Method 1
two or more overlapping radiation shields arranged within an inner vacuum space of a vacuum chamber... configured to block a majority of blackbody radiation from reaching the target
Implementation Method 2
sorbent materials to minimize gas saturation
Data Source
AI summary
Methods, systems, and devices for ultra or extreme-high vacuum are described. Such systems may comprise a vacuum chamber, a target within the vacuum chamber, two or more overlapping radiation shields arranged within an inner vacuum space of a vacuum chamber, and surrounding at least a portion of the target, a first and a second cooling element unit thermally coupled to a first and second radiation shield of the two or more overlapping radiation shields, wherein the first unit is configured to reduce the first radiation shield's temperature to at least <100K, and the second unit is configured to reduce the second radiation shield's temperature to at least <25K, and a third cooling element unit coupled to the target and isolated from the first and second radiation shield, wherein the third cooling element unit is configured to reduce the target's temperature to at least <4K.