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A liquid surface height controller for surface spectroscopy
James D Pickering1, Adam S Chatterley1, Mikkel Bregnhøj1
1Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark.
The Review of Scientific Instruments
|October 2, 2021
Summary
This study introduces an affordable liquid surface height controller for precise experiments. The system uses a laser, webcam, and pump to maintain liquid levels with micrometer accuracy over extended periods.
Area of Science:
- Experimental Physics
- Surface Science
- Spectroscopy
Background:
- Maintaining stable liquid surface height is critical for surface-sensitive experiments.
- Evaporation and other factors can cause significant changes in liquid levels.
- Existing methods may be complex or costly.
Purpose of the Study:
- To develop a simple, inexpensive, and accurate liquid surface height controller.
- To enable precise control of liquid levels in surface-sensitive measurements.
- To address the challenge of changing liquid heights due to evaporation.
Main Methods:
- Utilized a commercial laser pointer and USB webcam for surface monitoring.
- Integrated a syringe pump for active height adjustment.
- Developed custom control software for system operation.
- Tested the system's precision (±1 µm) and range (2.5 mm).
Main Results:
- Demonstrated stable control of a water surface height within ±5 µm over 8 hours.
- The system effectively compensates for changes caused by evaporation.
- Achieved high precision and long-term stability in liquid level maintenance.
Conclusions:
- The developed controller offers a cost-effective solution for precise liquid surface height management.
- It is suitable for applications like sum-frequency generation spectroscopy requiring stable interfaces.
- The system's stability and accuracy make it valuable for various surface science experiments.
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