## Absolute temperature directly from plank’s profile: A simulation

#### AUTHOR AND AFFILIATION

V. VIJAYAKUMAR
B-111, Saivihar, Sector-15, CBD-Belapur, NaviMumbai-400614 (India)

#### KEYWORDS:

Planck profile, Absolute Temperature scale, Temperature measurement

February 2021

9-19

#### ISSN:

2319-8044 (Online) – 2231-346X (Print)

Vol.33 – No.2

#### DOI:

http://dx.doi.org/10.22147/jusps-A/330201

#### ABSTRACT:

The measured thermal radiation from a material surface will, in general, have a wave length ($\lambda$) dependent scale-factor to the Planck profile (PT) from the contributions of the emissivity (Є$\lambda$) of the surface, the response function (A$\lambda$) of the measurement setup, and the emission via non-Plank processes. For obtaining the absolute temperature from such a profile, a procedure that take care of these dependencies and which relay on a temperature grid searchis proposed. In the procedure, the deviation between the Plank profiles at various temperatures and the measured spectrum that is made equal to it at a selected wavelength, by scaling, is used. The response function (A$\lambda$) is eliminated at the measurement stage and the polynomial dependence of the remnant scale factor mostly dominated by Є$\lambda$) i s extracted from the measured spectrum by identifying its optimal $\lambda$ dependence. It is shown that when such a computation is carried out over a temperature grid, the absolute temperature can be identified from the minimum of the above deviation. Here, search for T and Є$\lambda$) d elinked, unlike in the leastsquare approaches that are normally employed. Code that implements the procedure is tested with simulated Planck profile to which different viable values of Є$\lambda$) a nd noise is incorporated. It shown that if the $\lambda$ dependence of scale-factor is not too high, the absolute temperature can be recovered. A large $\lambda$ dependent scale-factor and the consequent possible error in the temperature obtained can also be identified.