Vacuum-Compatible Thermal Management for Cryogenic Sample Sublimation
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Solution Overview
Problem
Existing thermal management systems are not adapted to maintain a low temperature gradient around samples placed under vacuum and at cryogenic temperatures, which is necessary for applications like sublimating water ice from regolith for quantitative and isotope analyses.
Innovation Solution
A thermal management system comprising a thermal source, thermal sensors, a heating element, and a shield that exchanges heat by conduction, with a vacuum sealing feedthrough and insulator to maintain a low temperature gradient, allowing for precise control and measurement of temperature gradients around samples in vacuum environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a flow of gas is used to maintain low temperature gradient in the sample tube, then the temperature gradient is reduced, but the system cannot be used under vacuum conditions
Solution Approach 1:
The patent removes the gas flow requirement by extracting the thermal management function into a vacuum-compatible design using a cold finger and thermal conduction through a shield, eliminating the need for gas circulation while maintaining temperature control under vacuum
Solution Approach 2:
The patent introduces a thermal shield as an intermediary element that conducts heat from the cold source to the sample holder, enabling thermal management through conduction rather than convection, thus making the system vacuum-compatible
2Temperature
If the thermal source is placed in direct contact with the sample, then temperature control is improved, but gas deposition on the sample increases
Solution Approach 1:
The patent segments the thermal management system into distinct components: a cold source, a thermal shield, and a sample holder. This segmentation allows the cold source to be physically separated from the sample while still providing temperature control through the shield, preventing direct contact that would cause gas deposition
Solution Approach 2:
The thermal shield acts as an intermediary between the cold source and the sample, providing thermal conduction while maintaining physical separation. This prevents gas molecules from depositing on the sample while the shield itself receives the gas deposition, protecting the sample integrity
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
Enables precise control and measurement of low temperature gradients, preventing gas deposition and allowing for efficient sublimation and analysis of samples by maintaining a stable, low temperature environment.
Implementation Method 1
a heating element for heating the source
Implementation Method 2
a shield having a first end in direct contact with the thermal source at a first interface... the shield exchanges heat with the thermal source exclusively by conduction and exclusively at the first interface
Implementation Method 3
a vacuum sealing feedthrough comprising a thermal insulator element... the vacuum sealing feedthrough delimiting around the first interface a vacuum sealed volume
Data Source
AI summary
A thermal management system comprising: a thermal source of low to cryogenic temperature; a heating element for heating the source; a shield adapted to exchange heat by conduction to/from a sample and to/from the source; a controller calibrated for maintaining a gradient of temperature along the shield within a pre-determined range; a vacuum sealing feedthrough comprising a thermal insulator element, the vacuum sealing feedthrough delimiting around the first interface a vacuum sealed volume so that the shield exchanges heat with the thermal source exclusively by conduction and exclusively at a first interface. An exemplary purpose for this thermal management system is the sublimation of water ice and/or water ice trapped in a regolith, and positioned in a vacuum chamber. The heat insulator element is configured to separate physically the thermal source from a vacuum chamber into which the shield can protrude, so that sublimated compounds from the sample do not encounter colder point which would cause their deposition on the shield or on the walls of the chamber.