Cryogenic Sample Stage with Dual-Mode Cooling for Flexible Movement
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Solution Overview
Problem
Existing cooled moveable sample stages in scientific instruments face a design dilemma between achieving high heat transfer rates for rapid cooling and maintaining flexibility for movement, as a high heat transfer rate typically requires a stiff braid or foil.
Innovation Solution
Decoupling the initial cooling phase from maintaining the cooled temperature by using a cooling plate in contact with the sample stage in a parked position to achieve high heat transfer rates, and subsequently using a flexible heat transfer connection, such as a thin copper braid, to maintain the target temperature while allowing movement of the sample stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a thick and stiff braid or foil is used to provide high heat transfer rate, then cooling efficiency is improved, but flexibility and ease of movement deteriorate
Solution Approach 1:
The cooling system is segmented into two distinct components: a cooling plate for high-rate cooling and a flexible braid for maintenance cooling. This segmentation allows each component to be optimized for its specific function, resolving the contradiction between cooling efficiency and flexibility
Solution Approach 2:
The cooling plate performs preliminary action by rapidly cooling the sample stage to the target temperature before the sample stage moves to the imaging position. This preliminary high-rate cooling eliminates the need for a thick flexible braid during movement
2Productivity
If a thick braid or foil is used to achieve high heat transfer rate, then cooling performance is improved, but device complexity increases
Solution Approach 1:
The thermal connection is segmented into a rigid cooling plate for high heat transfer and a flexible braid for connectivity. This segmentation allows the high heat transfer function to be achieved without requiring the entire connection structure to be thick and complex
Solution Approach 2:
The cooling plate provides localized high heat transfer capability at the parking position, while the flexible braid provides distributed maintenance cooling during movement. This local quality approach optimizes heat transfer where needed without compromising flexibility elsewhere
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 enables rapid cooling of the sample to a target temperature using a high heat transfer rate and then maintains that temperature at a lower heat transfer rate, allowing for sufficient flexibility in the sample stage movement without interference.
Implementation Method 1
A cooling plate is provided in contact with the sample stage in a parked position of the sample stage to cool the sample stage through the cooling plate
Implementation Method 2
A thermally conductive flexible member, for example a conductive braid, such as a copper braid, thermally connects the sample holder and the cold finger to cool the sample holder through the thermally conductive flexible member
Implementation Method 3
A cold finger is in contact with a heat sink
Data Source
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AI summary
A scientific instrument, for example an electron microscope, is disclosed and comprises a moveable stage with a sample holder. A cold finger is in contact with a heat sink and comprises a cooling plate configured to contact the sample holder to cool the sample holder in a rapid cooling position. A thermally conductive flexible member thermally connects the sample holder and the cold finger to cool the sample holder away from the rapid cooling position, where the sample can be investigated, imaged, and the like. Embodiments are disclosed in which both the cold and the sample holder move or in which only the cold finger move between a rapid cooling and other configurations. Also disclosed is a corresponding method for operating the scientific instrument. The disclosure advantageously combines rapid cooling in the rapid cooling position with reduced limitation of movement of the sample holder away from the parked position.