Geochronology 

A conventional isochron is a straight line fit to two sets of isotopic ratios, D / d and P / d, where P is the radioactive parent, D is the radiogenic daughter and d is a second isotope of the daughter element. The slope of this line is proportional to the age of the system. An inverse isochron is linear fit through d / D and P / D. The horizontal intercept of this line is inversely proportional to the age. The latter approach is preferred when d < D, which is the case in Re–Os and K–Ca geochronology.

Our contribution enhances the infrared-radiofluorescence dating technique, used to determine the last sunlight exposure of potassium feldspars in a range of about 600 to 600.000 years backwards. We recorded radiofluorescence images of fine sands and processed them with tailored open-source software to obtain ages from single grains. Finally, we tested our new method successfully on two natural sediment samples. Studies in Earth science will benefit from improved age accuracy and new insights.