An absolute calibration source for laboratory and satellite infrared spectrometers

Area of Science:

• Metrology and Instrumentation
• Thermal Engineering
• Optics and Photonics

Background:

• Accurate temperature control is critical for radiometric measurements.
• Existing blackbody sources may lack compactness or precise temperature regulation.
• Thermoelectric cooling and heating offer potential for compact, stable thermal management.

Purpose of the Study:

• To develop and characterize a compact blackbody source with a wide operating temperature range.
• To achieve high emissivity and minimal thermal gradients for accurate thermal radiation.
• To demonstrate stable and responsive temperature control using thermoelectric heat pumping.

Main Methods:

• Designed a blackbody radiator using a blackened honeycomb cavity array.
• Integrated four matched, two-stage thermoelectric modules for heat pumping.
• Employed a temperature-regulated baffle system with independent proportional regulators.
• Incorporated multi-point temperature monitoring on the target and baffles.

Main Results:

• Achieved a blackbody emissivity greater than 0.995.
• Maintained small thermal gradients across the 65 cm(2) source area.
• Demonstrated stable operation and rapid response within the -40°C to +60°C range.
• Validated performance in non-absorbing atmospheres and vacuum conditions.

Conclusions:

• The developed compact blackbody source provides accurate and stable thermal radiation.
• Thermoelectric heat pumping is effective for precise temperature control in blackbody applications.
• The source is suitable for applications requiring high emissivity and minimal thermal gradients.