Potassium 40 argon 40 dating
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.
This imprecision (and inaccuracy) is transferred to the secondary minerals used daily by the Ar age equation will become continually more refined allowing much more accurate and precise ages to be determined.
Likewise, because of heterogeneity problems with the MMhb-1 sample, the K/Ar ages are not always reproducible.
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.
J value uncertainty can be minimized by constraining the geometry of the standard relative to the unknown, both vertically and horizontally.
The NMGRL does this by irradiating samples in machined aluminum disks where standards and unknowns alternate every other position.