LASUR carries out thermo-optical properties on all types of materials between -263 ° C and 3000 ° C for wavelengths ranging from UV to far infrared and angles of incidence from the normal up to 85° of inclination.
The thermo-optical properties (particularly the emissivity) are determining factors for energy exchange by radiation and for thermography measurements.
LASUR carries out thermo-optical measurements on your materials :
- Temperature range from -263°C up to 3000°C
Devices: Induction furnace, Resistance heating and cooling by liquid helium
- Wavelength: from UltraViolet (0.3 µm) to far Infrared (1000μm)
Detector: MCT, InSb, Si, InGaAs, UV pyrometer, IR cameras, spectral bolometer
- Directional measurement: from normal to 85°
Integration with hemispherical spectral quantities and total hemispherical quantities
- Error < 5% (in IR)
Specific system for high temperature measurements
Induction furnace heating
Temperature control by UV pyrometer (PYROPHOT)
Liquid nitrogen cooled enclosure for negligible wall radiation
Adding emissivity, as a multiplication factor to Planck’s Law which describes only blackbody radiation, must be used to characterize real bodies thermal radiation. For temperature measurements with a pyrometer, it is such a perturbing factor that there is no reliable data, especially concerning metals, on consequences of temperature and measurement wavelength variations on emissivity.
A systematic study would be very useful for a better understanding of how a body can be heated or cooled by radiation absorption or emission. One can study emissivity behavior at high and low temperatures as a function of the observation wavelength (spectral emissivity), of the observation angle (directional emissivity), or by integrating the overall possible values that these parameters can show (total emissivity).
Also some metallurgists have a special interest in studying the possible correlations between phase transitions and emissivity variations. It is well known that a solid-liquid transition results in an emissivity change. However, what is still to be established concerns the consequences on emissivity of metallurgical transformations after heat treatment.
Such variations can be observed on spectral as well as on total emissivity. LASUR offers an “emissivimeter-pyrometer” based on the principle that the radiated energy in the short wavelength range is highly sensitive to temperature, then, for large wavelengths, the sensitivity to emissivity is dominant. While the PYROPHOT pyrometer is measurement temperature at the shortest wavelength compatible with temperature levels, the spectral emissivity is simultaneously measured with maximum precision at a large wavelength.