The objective of this Phase I SBIR project is to develop new detection techniques for rare noble gas isotopes. Two different detector concepts which combine elements of mass spectroscopy, charge neutralization, photon burst and resonance ionization spectroscopy will be evaluated. The research offers the possibility of a breakthrough in detection capabilities of minute quantities of rare noble gas isotopes such as Argon-39. Argon-39 is ideally suited for studying the penetration of greenhouse gases across the thermocline and for the study of deep-ocean circulation.