TEM Sample Holder Pre-Cooling to Prevent Thermal Drift
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Solution Overview
Problem
The drift phenomenon occurring in transmission electron microscopes due to temperature differences between the sample holder and the microscope's internal environment affects image quality and analysis precision.
Innovation Solution
A sample holder equipped with a thermoelectric cooling device, including a core-shell or coil structure, is used to maintain the sample and holder at a temperature similar to the microscope's internal environment, preventing drift and ensuring precise analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sample holder is inserted from outside to inside the electron microscope without temperature control, then the operation is simple, but a drift phenomenon occurs due to temperature difference between the sample holder and the inside of the electron microscope
Solution Approach 1:
The thermoelectric cooling device is activated before the sample holder is inserted into the electron microscope to pre-cool the sample holder to a temperature close to the internal microscope environment. This preliminary temperature equalization prevents drift phenomenon during subsequent operation without requiring complex continuous temperature control mechanisms throughout the entire system.
Solution Approach 2:
The thermoelectric cooling device acts as an intermediary between the external environment and the electron microscope's internal vacuum environment. It mediates the temperature transition of the sample holder, allowing it to adapt from ambient temperature to the cooled microscope environment without causing thermal drift or contamination.
2Reliability
If liquid nitrogen is used to lower the internal temperature of the electron microscope, then the vacuum level and EDS detector performance are maintained, but a temperature difference is created between the inside and outside of the microscope
Solution Approach 1:
The temperature difference created by liquid nitrogen cooling, which initially causes drift when the sample holder is inserted, is converted into a benefit by using the thermoelectric cooling device to match the sample holder's temperature to the internal environment. This eliminates the harmful drift effect while preserving the necessary temperature conditions for vacuum maintenance and detector performance.
3Reliability
If the sample holder is cooled using a thermoelectric cooling device, then drift phenomenon is prevented, but additional device components are added to the sample holder
Solution Approach 1:
The mechanical complexity of continuous temperature control systems or liquid nitrogen cooling apparatus is replaced with a compact thermoelectric cooling device that uses electrical current to achieve temperature control. This substitution reduces mechanical complexity while maintaining effective drift prevention through solid-state thermoelectric cooling.
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 solution effectively prevents drift phenomena, allowing for immediate sample analysis without additional waiting time and enhancing image quality.
Implementation Method 1
A sample holder equipped with a thermoelectric cooling device, including a core-shell or coil structure, is used to maintain the sample and holder at a temperature similar to the microscope's internal environment
Data Source
AI summary
A sample holder for a transmission electron microscope may include: a column part that extends in a first direction; a stage configured to receive a sample, the stage disposed at a first end portion of the column part; a motor part disposed at a second end portion of the column part; and a thermoelectric cooling device disposed inside the column part.