in mid infra red?

What kind of light source? It might be possible that you can also calculate the inrensity.

I would not choose a spectrometer due to for example quantum yield aspects, ...

Article Method to analyse energy and intensity dependent photo-curin...

DWD use pyranometers and you can purchase intensity meters which are “calibrated“ within a specific range.

Laser power meters, with thermopile detectors having a flat response up to 6000 nm could be useful if you are interested in the wavelength range of concern for safety for humans, i.e < 3000 nm. The intensity you are considering is very high, It might be useful to obtain intensity from source temperarature and black body modeling.

Thank you all for your answers !

The wavelength is between 2.4-2.7 μm and that means the temperature field is up to about 900°C .

The aim of measurement is to make following comparison :

-Intensity vs. Distance, Temperature & Emissivity when aplying IR radiation of a plastic surface.

Aparna Sathya Murthy : Spectrometer can not help for this temp range and it is mainly used for Light or Sunlight

Michael Schmitt : How would you calculate the intensity?

pyranometer is a good idea but the problem is that, I did not find a pyranometer for more than 4kw/m² and maximum operation temp is 80°C. If there is a pyranometer up to 300°C, would be good.

Francesco Frigerio : can you give me a short Idea how to obtain intensity from source temperature and black body modeling?

appreciate your time and effort !

In the case that you use a tungsten filament the electrical power is correlated with the intensity in the IR range. But in all cases not more than the electrical input power can be converted.

If you want to see the spectral distribution you have to use a NIR-IR sensitive detector.

I think you do not need to measure the hole illumination at once. In the article I also used a optical filter OD=4 with reduced the illumination by a factor of 10000. You only need a reduction of a factor 10 or a corresponding beam expansion or a aperture. In the last case local distributions of the detector sensitivity might be possible (compare to the article).

Article Method to analyse energy and intensity dependent photo-curin...

I guess a IR camera (or a direct beam sensor - thermophil pyrheliometer) might in this case also work. But ask a distributor.

https://www.photonics.com/Splash.aspx?Tag=LATEST+PRODUCTS

In that wavelength range, the use of thermopile could work. Of course you can model sources as black bodies only as long as emissivity is known or can be neglected. Anyway see

Article Modelling Infrared Radiation Exposure by Black body-Like Sources

considering that the aim of the work was workers' protection