Problem Description
Lowering the temperature of a spectrometer can significantly enhance its performance. Cooling the CCD sensor provides several benefits:
- Reduced thermal noise, which interferes with measurement accuracy.
- Improved stability of components (e.g., detectors, optics) at lower temperatures.
- Minimized thermal expansion, preventing misalignment and distortions.
Target performance:
- Achieve −15 °C at the CCD sensor while operating in an ambient temperature of 35 °C.
- Maintain the overall spectrometer temperature around 10 °C.
Our Approach
Achieving such a temperature difference is challenging, especially in compact systems. To address this, we combined thermoelectric cooling, efficient heat dissipation, and thermal isolation strategies:
1. Thermoelectric Cooling (Peltier Modules)
We used two TEC (Peltier) modules to drive the cooling process:
- Module 1 (inside): Directly cools the CCD sensor.
- Module 2 (outside): Stabilizes the hot side of the first module, maintaining consistent performance.
The thermoelectric effect allows these modules to pump heat from one side to the other when they are powered. This process creates a controlled cooling environment.
2. Forced Convection Cooling
Both TEC modules are paired with heatsinks and fans to dissipate heat through forced convection. This improves efficiency and prevents overheating of the hot sides.
3. Vacuum Enclosure for the CCD Sensor
The CCD is housed in a vacuum-sealed chamber, which:
- Prevents condensation at very low temperatures.
- Provides strong thermal isolation.
- Ensures stable and repeatable cooling performance.
4. Acrylic Isolation Box for the Spectrometer
An acrylic enclosure was added around the spectrometer to help maintain stable internal conditions and improve overall thermal management.
Simulations’ Results
We ran thermal simulations to compare different configurations and select the most effective and feasible design. The results guided the final choice of enclosure geometry, TEC arrangement, and heat dissipation strategy.
Prototyping Results:
A prototype was built based on the optimized design.
- Thermal stability was confirmed through testing under real operating conditions
- The cooling system successfully achieved the target temperature range.
Renders:
