Determination of the temperature dynamics of materials under laser heating by spectral pyrometry method

Author(s):  
B.A. Lapshinov ◽  
◽  
N.I. Timchenko ◽  
Author(s):  
B.A. Lapshinov ◽  
◽  
N.I. Timchenko ◽  

Spectral pyrometry was used to determine the surface temperature distribution of Si, Nb, Cu, and graphite samples when they were locally heated by continuous radiation of an Nd:YAG laser (λ = 1.064 μm). With prolonged exposure to radiation, a stationary temperature field was established in the samples. The thermal spectra were recorded with a small spectrometer in the visible range in the temperature range above 850 K. The optical fiber used to transmit the radiation spectrum to the spectrometer had an additional diaphragm with a diameter of 1 mm located at a certain distance from the fiber end, which ensured the locality of the recorded spectra. The optical fiber moved continuously along the sample, and the spectrometer recorded up to 100 spectra with a frequency of 5-10 Hz. The temperature profile of the samples was calculated based on the results of processing the spectra using the Spectral Pyrometry program.


2016 ◽  
Vol 7 ◽  
pp. 767-775 ◽  
Author(s):  
Ayelet Ofarim ◽  
Bastian Kopp ◽  
Thomas Möller ◽  
León Martin ◽  
Johannes Boneberg ◽  
...  

We report the development of a novel method to determine the thermopower of atomic-sized gold contacts at low temperature. For these measurements a mechanically controllable break junction (MCBJ) system is used and a laser source generates a temperature difference of a few kelvins across the junction to create a thermo-voltage. Since the temperature difference enters directly into the Seebeck coefficient S = −ΔV/ΔT, the determination of the temperature plays an important role. We present a method for the determination of the temperature difference using a combination of a finite element simulation, which reveals the temperature distribution of the sample, and the measurement of the resistance change due to laser heating of sensor leads on both sides next to the junction. Our results for the measured thermopower are in agreement with recent reports in the literature.


1985 ◽  
Vol 25 (6) ◽  
pp. 779-781 ◽  
Author(s):  
E. Szil ◽  
L.B. Kiss ◽  
J. Kovács ◽  
P. Mogyorósi
Keyword(s):  

1991 ◽  
Vol 11 (2) ◽  
pp. 71-81 ◽  
Author(s):  
Yu. N. Zhitnev ◽  
A. V. Zakharchenko ◽  
N. Yu. Mordkovich ◽  
T.-B. H. Nugaev ◽  
E. A. Tveritinova ◽  
...  

The Pulsed Homogeneous Laser Pyrolysis (PHLP) of CHClF2 initiated by IOP(20) radiation of TEA-CO2 laser was carried out in the presence of SF6 sensitizer with the mixture components ratio 1:1 under partial pressure of the reactant equal to 1 Torr and 2 Torr.To describe PHLP process in the afterpulse period we suggested a kinetic model of CHClF2 thermal destruction accounting for the inhomogeneity of laser heating of the reaction mixture and its further cooling by the heat conduction mechanism. Applying the standard mathematical procedure for matching the experimental results of the degree of reactant destruction, and the numeric computations of this value made according to the suggested model, the Arrhenius parameters of the reaction of CHClF2 monomolecular conversion in the temperature range of 1000–1200 K were unambiguously determined. The values were obtained for the activation energy Eα = 52.8 ± 0.3 kcal/mol, and the pre-exponential factor A = (2.5 ± 1) · 1012 s−1.


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