LSC measurements of the half-life of 40K

Liquid scintillation counting techniques combined with the CIEMAT/NIST method have been applied to measure the specific activity of natural potassium salts. Samples have been prepared with three different scintillators. The individual atomic composition as well as the density of the cocktails have been taken into account for the efficiency calculation. With the specific activity the half-life is calculated to be T1/2=1.248(3)×109 a. The result is in reasonable agreement with other measurement results provided the same isotopic concentration of 40K is used.