Vibrationally isolated cryogenic shield for local high-quality vacuum
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Solution Overview
Problem
Generating regions of extreme high vacuum (XHV) or near-XHV in quantum information processing systems that rely on trapped ion technology is challenging due to outgassing of chamber materials, which limits ion lifetimes and introduces vibrations from cryogenic operations.
Innovation Solution
A vibrationally isolated cryogenic cold finger with a high surface area cryogenic sorption material is used to cap a controlled volume, ensuring outgassing materials bounce off the sorption material before reaching the critical area, acting as a cryogenic pump and minimizing vibrations by loose mechanical connection and soft vacuum bellows isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cryogenic operations are used to reduce outgassing and achieve XHV, then vacuum quality is improved, but vibrations are introduced from piston motion and cryogen flow
Solution Approach 1:
The vacuum system is segmented into a cold region (containing the cold finger with sorption material) and a warm region (containing the ion trap). This segmentation allows the cold region to handle vacuum pumping while the warm region provides a stable, vibration-free environment for the ion trap, resolving the contradiction between achieving XHV through cryogenic operations and minimizing vibrations that harm ion confinement.
Solution Approach 2:
The harmful vibration-generating cryogenic operations (piston motion, cryogen flow) are extracted and isolated from the critical ion trap region. The cold finger is suspended and thermally isolated from the main chamber, so that vibrations from cryogenic operations are confined to the cold region and do not propagate to the warm ion trap region, allowing XHV to be achieved without transmitting harmful vibrations.
2Temperature
If the cold finger is rigidly connected to the chamber for stable cooling, then cooling efficiency is improved, but vibrations are transmitted to the critical volume
Solution Approach 1:
The cold finger employs different mechanical connection qualities at different locations: a rigid thermal connection to the cooling source for efficient heat transfer, and a flexible/suspended connection to the chamber for vibration isolation. This local differentiation of connection properties allows simultaneous achievement of effective cooling and vibration minimization.
Solution Approach 2:
A flexible mounting mechanism or suspension system acts as an intermediary between the cold finger and the vacuum chamber. This intermediary provides sufficient mechanical support and thermal conduction for cooling while filtering out and isolating vibrations from the critical volume, resolving the contradiction between stable cooling and vibration transmission.
3Reliability
If cryogenic cooling is applied to the entire chamber, then outgassing is reduced, but connectivity and power load capabilities are limited
Solution Approach 1:
Cryogenic cooling is applied locally only to the cold finger region rather than the entire chamber. The cold finger is cooled to cryogenic temperatures to provide high-capacity vacuum pumping and reduce outgassing in the critical volume, while the rest of the chamber remains at room temperature, maintaining full connectivity and power load capabilities for various devices and components.
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 provides a localized region of XHV or near-XHV over ion traps while maintaining room temperature ultra-high vacuum (UHV) in other areas, extending ion lifetimes and reducing vibrations, thus enhancing the performance of quantum information processing systems.
Implementation Method 1
Cooling chambers to cryogenic temperatures (e.g., 4K) may greatly reduce the outgassing pressures of the materials and may provide pumping of materials that freeze on the surfaces or are trapped by cryogenic sorption.
Implementation Method 2
Cooling chambers to cryogenic temperatures (e.g., 4K) may greatly reduce the outgassing pressures of the materials and may provide pumping of materials that freeze on the surfaces
Data Source
AI summary
The disclosure describes various aspects of a vibrationally isolated cryogenic shield for local high-quality vacuum. More specifically, the disclosure describes a cryogenic vacuum system replicated in a small volume in a mostly room temperature ultra-high vacuum (UHV) system by capping the volume with a suspended cryogenic cold finger coated with a high surface area sorption material to produce a localized extreme high vacuum (XHV) or near-XHV region. The system is designed to ensure that all paths from outgassing materials to the control volume, including multiple bounce paths off other warm surfaces, require at least one bounce off of the high surface area sorption material on the cold finger. The outgassing materials can therefore be pumped before reaching the control volume. To minimize vibrations, the cold finger is only loosely, mechanically connected to the rest of the chamber, and the isolated along with the cryogenic system via soft vacuum bellows.