Radiation thermometry: The measurement problem

Classic article by G. D. (Gene) Nutter from a NASA ARCHIVE et.al.

ASTM STP895 Cover
ASTM STP895 Cover (Image credit ASTM International)

This online article is very similar and covers most of the same materials as  “Radiation Thermometry — The Measurement Problem” delivered at a symposium sponsored by ASTM Committee E-20 on Temperature Measurement in cooperation with the National Bureau of Standards, Gaithersburg, MD on May 8, 1984.

This was subsequently published as the first chapter in the volume “Applications of Radiation Thermometry”, ASTM SPECIAL TECHNICAL PUBLICATION 895, J.C. Richmond, National Bureau of Standards and D.P. DeWitt, editors.

 

Radiation Thermometry—The Measurement Problem
Symposium Paper

January 1985 — STP895  STP38703S
The basic measurement problems of radiation thermometry are discussed, with emphasis on the physical processes giving rise to the emissivity effects observed in real materials. Emissivity is shown to derive from bulk absorptivity properties of the material. Blackbody radiation is produced within an opaque isothermal material, with partial internal reflection occurring at the surface.

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Gene Nutter wrote this and many other  technical articles on the subject of radiation thermometry, including another classic , “A High Precision Automatic Optical Pyrometer in Temperatures ITS measurement and Control in Science and Industry, Vol. 4, 519-530, Instrument Society of America (1972).

Description: “An overview of the theory and techniques of radiometric thermometry is presented. The characteristics of thermal radiators (targets) are discussed along with surface roughness and oxidation effects, fresnel reflection and subsurface effects in dielectrics.

“The effects of the optical medium between the radiating target and the radiation thermometer are characterized including atmospheric effects, ambient temperature and dust environment effects and the influence of measurement windows.

“The optical and photodetection components of radiation thermometers are described and techniques for the correction of emissivity effects are addressed.”

NASA Info:Link to article: https://archive.org/details/NASA_NTRS_Archive_19880014512

Publication date 1988-03-01
Topics NASA Technical Reports Server (NTRS), INFRARED RADIOMETERS, RADIATION PYROMETERS, TEMPERATURE MEASUREMENT, THERMOMETERS, BLACK BODY RADIATION, RADIANCE, SPACE COMMERCIALIZATION, SURFACE ROUGHNESS, THERMAL EMISSION, Nutter, G. D.,
Collection NASA_NTRS_Archive; additional_collections
Language English
Identifier NASA_NTRS_Archive_19880014512
Identifier-ark ark:/13960/t9h46mr2v
Ocr ABBYY FineReader 11.0
Pages 61

Ed Note (from the book jacket of the 1988 book “Theory and Practice of Radiation Thermometry”,  Edited by D.P. Dewitt and Gene D. Nutter, John Wiley & Sons, Inc.): “Gene D. Nutter is (was)  a senior staff member of the Instrumentation Center, College of Engineering, University of Wisconsin-Madison. He received his MS in Physics from  University of Nebraska and had been earlier associated with the National Bureau of Standards and Atomics International.”

Chapter 5 in the above referenced text is linked below below. a classic book on the theory & practices of radiation thermometry published in 1998. It was recently found on Amazon.com and ebay.com at the following links:

https://www.amazon.com/dp/0471610186/ref=rdr_ext_tmb FOR ABOUT $349.

AND for between $353 and $453 on ebay at:  https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR0.TRC0.H0.Xtheory+%26+practice+of+radiation+thermometry.TRS0&_nkw=theory+%26+practice+of+radiation+thermometry&_sacat=0

 

Understanding Radiation Thermometry Parts I & II

From NASA Technical Reports Server (NTRS)

From NASA Article
From NASA Article

In 2015, Timothy K. Risch of NASA developed two technical articles that are available on the NASA Technical Reports Server (NTRS).

Both articles may be freely downloaded from NTRS in various formats, as long as the NASA Server maintains their presence.

As far as we know these are royalty free and the only stipulation that NASA usually requires is an attribution. These are below in the form of links to the article on the NASA web site.

The articles are entitled:

Understanding Radiation Thermometry. Part I, 71 pages, publication date 2015-07-08, and Understanding Radiation Thermometry. Part II, 111 pages, same publication date.

We have reviewed these documents and find them to be an excellent summary of this temperature measurement method and have archived them on our site in two formats, mobi, suitable for reading on an E-reader and in Adobe pdf format.

Part 1 provides and Overview, Nomenclature, a bit about what temperature is and the history of measurement methods and delves into the physics underlying Radiation Thermometry.

Part II covers practical radiation thermometers, some detail on measurement techniques and calibration and a brief reference list.

These files are linked below many be freely downloaded as long as we maintain this website.

The NASA description for both article reads as follows:

This document is a two-part course on the theory and practice of radiation thermometry.

Radiation thermometry is the technique for determining the temperature of a surface or a volume by measuring the electromagnetic radiation it emits.

This course covers the theory and practice of radiative thermometry and emphasizes the modern application of the field using commercially available electronic detectors and optical components.

The course covers the historical development of the field, the fundamental physics of radiative surfaces, along with modern measurement methods and equipment.
NASA Technical Reports Server (NTRS) 20150021314 Understanding Radiation Thermometry. Part I NASA Technical Reports Server (NTRS) Free Download & Streaming Internet Archive

Understanding Radiation Thermometry – Part I pdf Format Timothy K. Risch NASA Armstrong Flight Research Center July 8, 2015

NASA Technical Reports Server (NTRS) 20150021315 Understanding Radiation Thermometry. Part II NASA Technical Reports Server (NTRS) Free Download & Streaming Internet Archive

Understanding Radiation Thermometry – Part II pdf Format Timothy K. Risch NASA Armstrong Flight Research Center July 8, 2015

Sources on the NASA Technical Reports Server:

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150021314.pdf

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150021315.pdf

Thermography Resources:

Organizations & Meetings

Some of the organizations and meetings shown below are run by training companies and one, the Annual Thermosense Conference, is a technical conferences for thermographers and others involved in R&D, Equipment Development, Process applications and other uses in both Imaging and Sensing via infrared means.

This latter meeting usually runs for 3 1/2 days in the Spring, rotating between Orlando Florida, Baltimore, Maryland and Anaheim, California. It is held in conjunction with a large equipment exhibition and several high tech conferences, all under the banner of a SPIE (The International Society for Optical Engineering) meeting.

  • African Thermograpy User Group
    An Association of Thermography organizations in Southern Africa with about 12 members. Web site has references to training programs run by nearby office of Asea Brown Boveri(ABB).
  • ASNT
    The Association for Non Destructive Testing
    in Columbus Ohio, USA. There are other national organizations around the world affiliated with ASNT and links to them are on this web site.
  • ASTM International
    The American Society for Testing and Materials is one of the largest developers of voluntary consensus standards in the world. There are several committees within ASTM that are active in developing and maintaining standards related to Non-contact temperature measurement and thermal imaging in NDT/NDE.
  • IR/Info
    A Web site and Annual Training Conference with lots of information, Also a connections to an Internet discussion forum, sponsored by The Infraspection Institute.
  • InfraMation
    An e-Newsletter and a topical meeting sponsored by The Infrared Training Center, division of FLIR-InfraMation 2003 is already in the works, and is planned to be held in Orlando, Florida. Contact abstracts@inframation.org.
  • JCDPublishing
    Winter Park, Florida (USA) A publisher of specialty books related to IR and thermal imaging, Also runs training courses for organizations including SPIE. Run by a well-known specialist in IR imaging technology, Gerry Holst.
  • Professional Thermographers Association
    Provides a Directory of Infrared Consulting Companies, Key Points to Choosing an Infrared Consulting Company , Specifications to consider when contracting an Infrared Consulting Company and Generic Specifications for the contracting of an Infrared Electrical / Mechanical PdM inspection to insure that you get a quality job.
  • The Quantitative InfraRed Thermography Conference
    An international conference. Up to now, there has been twelve QIRT conferences (see Archive Section for the complete list).
  • The Snell Group
    An organization that provides many training courses for both Infrared Thermographers and also Motor Inspectors,
  • SPIE Thermosense
    A broad, topical meeting for the international IR Thermal Imaging and sensing technology community. Program on the Thermosense Web site. View the SPIE website for registration and arrangements information.
  • UK Thermographers Association
    UKTA-A national organization based in Bracknell, England with many many links to the USA and other parts of the world.

Optical Pyrometers & Vendors

How They Work

And Who (Still*) Makes Them

The Optical Pyrometer is a highly-developed and well accepted noncontact temperature measurement device with a long and varied past from its origins more than 100 years ago.

In spite of the fact that more modern, automatic devices have nearly displaced it, several makers still produce and sell profitable quantities each year.

In general, opticals, as they are often called, can be described as fitting into two seperate types, according to the two USA companies that produce them.

However, there are actually several different types that vary in complexity and cost. A quick review of the descriptions below will provide some of the differences and a check of the web sites of the two companies will yield even more information.

We suspect that there are other makers overseas and we are looking to find more details about them and their web presence.

How Optical Pyrometers Work

Optical Pyrometers work on the basic principle of using the human eye to match the brightness of the hot object to the brightness of a calibrated lamp filament inside the instrument.

The optical system contains filters that restrict the wavelength-sensitivity of the devices to a narrow wavelength band around 0.65 to 0.66 microns (the red region of the visible spectrum).

Other filters reduce the intensity so that one instrument can have a relatively wide temperature range capability. Needless to say, by restricting the wavelength response of the device to the red region of the visible, it can only be used to measure objects that are hot enough to be incandescent, or glowing.

This limits the lower end of the temperature measurement range of these devices to about 700 °C.Some experimental devices have been built using light amplifiers to extend the range downwards, but the devices become quite cumbersome, fragile and expensive.

Modern radiation thermometers provide the capability to measure within and below the range of the optical pyrometer with equal or better measurement precision plus faster time response, precise emissivity correction capability, better calibration stability, enhanced ruggedness and relatively modest cost.

This Illustration graphically how it looks to a user via a html pagesin Microsoft Power Point presentation format, with basic artwork courtesy of Spectrodyne, Inc.

The entire slide show also can be downloaded in a self-extracting compressed format and then viewed using a free Power Point viewer available from Microsoft.

To extract the slides from the compressed file, copy the file to its own subdirectory and then run it. It will extract the files into PowerPoint format, i.e. having file extension names of *.ppt.
Then run the viewer and open the show “OPYRO”, in the appropriate subdirectory or the individual sldes by their file names.

If you have some comments or questions, let us know.