Size-of-Source Effect Sensitivities

In Most IR Thermometers & In Filter Radiometers

SSE Poster imageOnline — A recent online copy of a significant technical poster, Size-of-Source Effect Sensitivities In Filter Radiometers, (Authors: M. R. Dury, T. C. Arneil, G. Machin and M. Goodman), on the National Physical Laboratory (NPL) website?? is now freely available as a PDF (1.05MB) download online on the site.

The introduction to the article begins:

“When performing high accuracy radiation thermometry, the size-of-source effect (SSE) of a filter radiometer* can provide a significant contribution to the uncertainties** associated with the measurements.”

Size-of-Source Effect Sensitivities In Filter Radiometers

The article is available online at: and, at present ,on the NPL website at:

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* ED NOTE 1: For newbies to non-contact temperature measurements by Radiation Thermometers (Infrared Thermometers or Radiation Pyrometers) the SSE is a known, often very significant, error source in both calibrating and using such sensors.?? For a relatively inexpensive primer on the topic read the article “Establishing a Calibration Laboratory for Industrial Radiation Thermometry” by Barber & Brown, in the little 1985 ASTM book, available as a paid PDF download at: ( ) – “Applications of Radiation Thermometry”

** ED NOTE 2: The term Uncertainty is the technically preferred term describing inaccuracy or error in measurement and often a difficult part of any measurement process is proving that the most likely error is within acceptable tolerance limits.