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Looking at the Gallium Fixed Point
This featured video we are looking at the Gallium Fixed Point . The International Temperature Scale of 1990, ITS-90 defines temperature with a range of fixed points. The Gallium Fixed Point, 29.7646°C is easy to realise and for resistance thermometers can give us very useful information.
Why use a Gallium Fixed Point Cell?
A Gallium Fixed Point can allow you to achieve a calibration at 29.7646°C to a very low uncertainty. Gallium cells are used in Primary Laboratories to disseminate the ITS-90, outside of the Primary Laboratory, many other laboratories also use Gallium cells to check their in-house standards and to help calibrate high accuracy thermometers
What types of Cell and Apparatus are available?
For Primary Laboratories, Isotech has an optimal cell and apparatus to automatically operate the cell with a calibration uncertainty to 0.25 mK. Additionally, there is a smaller, cost-effective model than can be used in dry blocks and liquid baths that can provide an uncertainty as low as 0.5 mK. In addition to cells for contact thermometers, we also have a blackbody fixed-point cell for calibrating IR thermometers.
What is WGA?
WGA is the Ratio of the Resistance at the Water Triple Point to the Resistance at the Gallium Point, this data is very useful for verifying the performance of resistance thermometers. The ITS-90 states that for an SPRT this ratio has be > 1.11807. The ratio tells us about the quality of the platinum wire, tracking WGA in between calibrations gives us confidence in the performance of resistance thermometers
If your business would benefit our support with temperature calibration equipment contact us today for a free consultation.
