Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 34: Metal Substrates: Structure, Epitaxy and Growth

O 34.1: Poster

Tuesday, March 17, 2015, 18:15–21:00, Poster A

Emissivity of polished tungsten surfaces as a function of temperature, detection angle and wavelength — •Mate Puljiz, Sara Wanjelik, and Mathias Getzlaff — Institute of Applied Physics, University of Düsseldorf

The temperature of heated metallic surfaces in UHV chambers is usually measured by infrared pyrometry. Since metals cannot be regarded as black bodies, the material-dependent emissivity must be known in order to obtain accurate temperature data.

In this contribution, we report on the emissivity of a smooth polished tungsten surface with respect to its dependence on temperature, detection angle and wavelength. For this purpose, a temperature measurement using a W/Re thermocouple being in contact with the sample as reference was carried out simultaneously with a pyrometric measurement of the spectral radiance at wavelengths of 0.96 and 1.6 μm in a temperature range from 523 to 2473K. The sample was mounted rotatably in order to allow measurements for different detection angles. Subsequently, the emissivity was calculated using the measured data according to Planck's law. The results show a distinct angular dependence of the emissivity.