||A delayed coincidence counting system originally developed by Giffin et al. (1963), and modified by Moore and Arnold (1996). Measures radium isotopes (224Ra, 223Ra and 226Ra) in water samples. The system records decay events in three different channels, depending on the time elapsed between two subsequent signals, which reflect the half-lives of decay products in radium decay chains. It consists of a scintillation cell connected to a photomultiplier to detect radioactive decay events, an electronic gateway system, which registers counts and splits the registered events into different channels, depending on the time elapsed until the next event happens, and a pump, which continuously pumps helium through the sample (on an acrylic fibre coated with manganese dioxide, Mn fibre), and subsequently through the scintillation chamber. Further description can be found in https://doi.org/10.4319/lom.2013.11.594.