Low-Temperature Sample Holder for Vibration-Free Electron Microscopy
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Solution Overview
Problem
Existing methods for cooling samples below ambient temperature for electron microscopy, such as evaporative cooling with liquid nitrogen, introduce disruptive vibrations that hinder long exposure data collection.
Innovation Solution
A low temperature sample rod device for side entry electron microscopes, comprising a conduction rod, a thermoelectric module, a coupler, and a thermal battery, which transfers heat without gas flow, minimizing vibrations and allowing for precise temperature control between 233K and 333K.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If evaporative cooling from liquid nitrogen is used to cool the sample, then the sample temperature is reduced to approximately 77K, but disruptive vibrations are transmitted to the sample from the boiling liquid nitrogen
Solution Approach 1:
The patent replaces the mechanical/physical system of liquid nitrogen evaporative cooling with a thermoelectric module (solid-state cooling device). This substitution eliminates the boiling process that generates vibrations, while still achieving the desired cooling effect through electrical energy conversion.
Solution Approach 2:
The patent changes the cooling mechanism from phase-change-based (evaporative cooling at fixed 77K) to thermoelectric-based cooling, which allows continuous temperature adjustment. The thermal battery material's phase change temperature is specifically selected to match the desired sample temperature, providing precise thermal control without vibrations.
2Temperature
If liquid nitrogen evaporative cooling is used, then cooling below ambient temperature is achieved, but the method is limited to one temperature (boiling point of nitrogen) without introducing vibrations
Solution Approach 1:
The patent transforms the static, fixed-temperature cooling system (liquid nitrogen at 77K) into a dynamic, adjustable-temperature system using a thermoelectric module. The module can be controlled to achieve various temperatures, and the thermal battery's phase change temperature can be selected to match different desired sample temperatures, providing versatility.
Solution Approach 2:
The patent changes the cooling mechanism from phase-change-based (evaporative cooling at fixed 77K) to thermoelectric-based cooling, which allows continuous temperature adjustment. The thermal battery material's phase change temperature is specifically selected to match the desired sample temperature, providing precise thermal control without vibrations.
3Object-affected harmful factors
If a thermoelectric module is used to transfer heat, then vibrations are minimized, but the device complexity increases due to additional components (conduction rod, coupler, thermal battery)
Solution Approach 1:
The patent combines multiple functions into integrated components. The conduction rod serves as both a structural support and a thermal conduction path. The coupler integrates mechanical attachment with thermal contact. The thermal battery combines phase-change cooling with temperature regulation, eliminating the need for separate cooling systems.
Solution Approach 2:
The thermoelectric module serves multiple functions: it provides cooling, enables temperature regulation, and acts as a heat pump. The thermal battery not only cools the sample but also maintains temperature stability through its phase change properties, reducing the need for additional temperature control mechanisms.
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
The device effectively cools samples to 233K or lower without introducing significant vibrations, enabling stable and precise imaging in electron microscopes, while also allowing for heating up to 333K.
Implementation Method 1
The thermoelectric module has a first side thermally coupled to the second end of the conduction rod and a second side opposite and spaced apart from the first side. The thermoelectric module is configured to transfer heat between the first side and the second side when supplied with electricity.
Implementation Method 2
The thermal battery includes a material that can be melted from a solid phase to a liquid phase by heat transferred from the first end of the conduction rod, through the thermoelectric module, through the coupler, and into the thermal battery.
Data Source
AI summary
Various implementations include a low temperature sample rod device for side entry electron microscopes. The device includes a conduction rod, a thermoelectric module, a coupler, and a thermal battery. The conduction rod has a first end configured to support a sample. The thermoelectric module has a first side thermally coupled to a second end of the conduction rod. The thermoelectric module is configured to transfer heat between the first side and a second side when supplied with electricity. The coupler has a first coupling surface thermally coupled to the second side of the thermoelectric module. The thermal battery has a battery coupling surface configured to be thermally coupled to a second coupling surface of the coupler. The thermal battery includes a material that can be melted from solid to liquid phase by heat transferred from the conduction rod, through the thermoelectric module, through the coupler, and into the thermal battery.