Blackbody calibration sources manufactured by Nagman maked it possible for infrared temperature sensors to calibrate with minimal error. This article will describe what characteristics the ideal blackbody calibration source for a certain application should have, as well as the factors that should guide your decision when selecting one.
What is a Blackbody Calibration Source?
An instrument that is used to verify the accuracy of the calibration of an infrared temperature probe is known as a blackbody calibration source. A heated (or cooled) target item with a temperature that is exactly known serves as the foundation for the reliable calibration of infrared pyrometers. This kind of target may either be heated.
A blackbody is a perfect radiator, which means that it emits thermal energy in both the visible and infrared spectrums, the intensity of which, for any specific wavelength and temperature, is determined by Planck’s Law of Radiation. It has an emissivity value of 1 and totally absorbs and emits all radiation, making it exceptionally non-reflective; also, its rating is 1.
In actuality, a blackbody calibration source will always have an emissivity that is somewhat lower than 1, although it is feasible to come very near to this value by careful design. This is due to the fact that there is no material that could be used to construct a genuine perfect blackbody.
A blackbody’s transmittance should be matched using the sensor’s emittance setting, and the sensor itself should be situated near enough to the blackbody such that the recorded spot diameter is no more than half the opening diameter.
Types of Blackbody Calibration Sources
Blackbody sources may be divided into two distinct Hot plate-type types and cavity-type blackbody sources.
Hot plate-type: It is standard practice to paint broiler pan blackbody sources with flat black paint in order to boost the plate’s emissivity. Hot plate-type blackbody sources are made of metal plates that can have their temperatures regulated. Either a basic thermostat or a more complex temperature controller may be used to set and maintain the temperatures of the plate. This category of blackbody sources may have an emissivity value as high as 0.95.
Cavity Type: The blackbody with a cavity is the most accurate representation of a black body, yet it is also the most complicated. It is a dark space that has an opening, also called an aperture. A temperature controller is used in order to maintain a consistent temperature inside the cavity. Any light that strikes the aperture from outside will enter the cavity, where it will be thermalized to the same energy as the cavity’s natural radiation and be converted into heat. Because of this, the only radiation that will be able to leave the cavity will be thermal radiation, which is exclusively determined by the temperature of the cavity. This approach has the potential to produce an emissivity of 0.98 or higher.
Difference Between Blackbody Calibrator and Flat-type IR Temperature Calibrator
When choosing a thermal imaging calibrator, one of the first things you’ll notice is the large range of form factors and target designs available. The target of a blackbody calibrator is an empty cavity with a tiny aperture. A conical or tube-shaped well that is incorporated into a bath, furnace, or heat pipe is a common example of this sort of radiation source. Due to its greater emissivity value, blackbody calibrators are often utilized at the reference level of radiation thermometry.
The painted target surface of other kinds of thermal imaging calibrators, sometimes called flat-plate IR temperature calibrators, is heated or cooled to the necessary calibration temperatures. The flat-plate surfaces might contain ridges or bumps, or they could be entirely level and smooth. Manufacturers of products utilize these different surface types in an effort to control emissivity, but they are likely adversely influencing temperature uniformity, another crucial metric.
Nagman is the company to go to for all of your blackbody radiation source needs since they are the industry leaders. We have a wealth of expertise that cannot be matched in the field of producing high-emissivity black body radiation sources that have excellent surface uniformity and accurate temperature control. We are proud to provide a diverse selection of blackbody aperture diameters in conjunction with adaptable temperature sensors that are designed specifically for more frequent periodic calibrations.