The monitoring of the interfering reactions is performed through the use of laboratory salts and glasses.For example, to determine the amount of reactor produced Ar ratio of the glass is then measured in the mass spectrometer to determine the correction factor that must be applied to the rest of the samples in that irradiation.For example, laser spot sizes of 100 microns or less allow a user to extract multiple argon samples from across a small mica or feldspar grain.The results from a laser probe can be plotted in several graphical ways, including a map of a grain showing lateral argon distribution.The isotopes the KAr system relies on are Potassium (K) and Argon (Ar).
Because this (primary) standard ultimately cannot be determined by Ar, it must be first determined by another isotopic dating method.
However, the Argon, a noble gas, constitutes approximately 0.1-5% of the Earth's present day atmosphere.
Because it is present within the atmosphere, every rock and mineral will have some quantity of Argon.
However, because each of these parameters is difficult to determine independantly, a mineral standard, or monitor, of known age is irradiated with the samples of unknown age.
The monitor flux can then be extrapolated to the samples, thereby determining their flux.