"Calibration of a QEM-EDS system for rapid determination of potassium c" by Kieran O'Gorman, Frank Brink et al.
Potassium (K)-rich feldspars are one of two mineral types typically used for optical dating. Feldspar grains can contain up to ~14 wt% K that gives rise to an internal dose rate component. This internal component can comprise a significant proportion of the total environmental dose rate to which a mineral grain is exposed. The environmental dose rate term—the denominator in the optical age equation—determines the rate at which electronic charge is transferred into the crystal lattice of a mineral grain over its period of burial. Not all feldspar grains have the same K concentration, so int...
Source: uow.edu.au