Optical pyrometer based on the gas phase photoacoustic effect.

Area of Science:

• Optics
• Thermodynamics
• Spectroscopy

Background:

• Accurate measurement of temperature differences is crucial in various scientific and industrial applications.
• Existing methods for differential radiation detection can be limited in sensitivity and specificity.

Purpose of the Study:

• To develop and validate a photoacoustic pyrometer for sensitive differential detection of infrared radiation.
• To investigate the theoretical basis and experimental factors influencing the pyrometer's performance.

Main Methods:

• Utilized a photoacoustic cell with infrared-active gas and transmitting windows.
• Employed chopping wheels for alternate viewing of two bodies at different temperatures.
• Developed a theoretical model for photoacoustic signal generation based on radiation incidence and gas absorption.

Main Results:

• The photoacoustic pyrometer demonstrated sensitivity to relative body temperatures.
• Instrument response was correlated with gas absorption coefficient and modulation frequency.
• The device effectively detected a null in integrated radiation incidence between the two bodies.

Conclusions:

• The developed photoacoustic pyrometer serves as a sensitive differential detector of infrared radiation.
• The instrument's performance is governed by temperature differentials, gas properties, and modulation parameters.
• This technology offers a novel approach for precise temperature difference measurements.