High temperature measurement in fast phenomena by spectrometry of photoelectrons
K.N. Kasparov, G.D. Ivlev, L.I. Belaziorava, V.N. Mironov and O.G. Penyazkov
The paper briefly presents the physical principles of the temperature measurement method by the spectrum of photoelectrons emitted by the radiation of a heated body, its theoretical justification and experimental confirmation. It is shown that Wien’s displacement in the thermal radiation spectrum caused by a change of temperature is consistent with the identical maximum shift in Maxwell’s energy distribution of photoelectrons. Hence this allows to measure a temperature by the energy spectrum of photoelectrons. It is proved that the temperature measured by the relation of two photocurrent levels corresponding to non-modulated and modulated ones by retarding potential is the spectral distribution (or integral color) temperature.
The dependence of a procedural error on the width of the region of the spectral sensitivity of a photocathode is shown. Diagrams to determine a procedural error by absolute value and spectral distribution of an object emissivity are presented. For most materials, it does not exceed 0.3%. The device based on a photoelectron multiplier allows to measure an integral color temperature in 10–6 s. Metrological measurements are made at laserpulsed irradiation of platinum in vacuum, and silicon. A temperature developing during iron powder combustion in oxygen atmosphere at a pressure from 3 to 11 bars is measured.
Keywords: Fast temperature measurement, photoelectron spectrometry, procedural error, metrology, iron powder combustion.