Detection of trace deuterium in depleted protium by MeV ion beam techniques

Abstract

Deuterium can be depleted in hydrogen to an atomic fraction well below 10−7. Due to molecular interferences (H2) and contamination issues it is not trivial to measure such low deuterium levels by mass spectrometry. By using accelerator mass spectrometry (AMS) molecular interferences can be completely suppressed and the detection limit is only determined by contamination with natural hydrogen. Three techniques have been used to produce the hydrogen ion beam: sputtering of hydrogenated titanium, a plasma gas ion source and a cesium sputter source with gas inlet. With the latter technique a D/H background level of 6×10−9 has been achieved. This is more than one order of magnitude better than with the other two methods. RBS and ERD have been used to track the natural and depleted hydrogen and surface oxidation during hydrogenation. The measured deuterium level is relevant for the interpretation of muon capture experiments.