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After establishing a calibration on an x-ray fluoruescence instrument it is desirable to use it for as long as possible without adjustment. This wouldn’t be a problem if the instrument did not change in sensitivity over time but this is not the case. The x-ray tube loses intensity and the detector loses sensitivity. Service work such as changing an x-ray tube or a crystal will effect the sensitivity also. To further complicate this, the loss on intensity will not be the same for all elements. Lighter element will be effected more than heavier ones.
To measure over a long period of time without having to re calibrate, the change in intensity for an element has to be monitored and corrected. A drift monitor can be used to do this, without the need for the calibration standards. They are also known as monitor samples, reference samples or monitor standards.
The main property of a drift monitor is that element intensities must be completely stable. Depending on the application, most monitors are made from glass or metal.
All FLUXANA calibrations are provided with a suitable set of drift monitors. These are developed and manufactured by FLUXANA and special monitors can be developed for other specific calibrations.
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