The KDK (potassium decay) experiment

Potassium-40 (40K) is a background in many rare-event searches and may well play a role in interpreting results from the DAMA dark-matter search. The electron-capture decay of 40K to the ground state of 40 Ar has never been measured and contributes an unknown amount of background. The KDK (potassium decay) collaboration will measure this branching ratio using a 40K source, an X-ray detector, and the Modular Total Absorption Spectrometer at Oak Ridge National Laboratory.