Study of Heavy Ammonia Production and Hydrogen Isotope Exchange in Ammonia on Surfaces Exposed to Deuterium/Nitrogen

Here we present results of an experiment where sample surface was exposed to the deuterium and deuterium/nitrogen plasma produced in an Electron Cyclotron Resonance (ECR) plasma gun mounted in an UHV chamber. The ECR plasma gun was mounted in front of a polycrystalline tungsten sample and neutral atmosphere composition was monitored by mass spectrometer in real time. Our results indicate that concentration of heavy ammonia (ND3) under steady exposure of tungsten to deuterium/nitrogen plasma depends on sample temperature. In our case the amount of ND3 increased from 60 degrees C to 200 degrees C and decreased after that until our highest temperature of about 600 degrees C. In another experiment, a sample was subjected to a neutral NH3 flow while exposed to pure deuterium plasma. In this case we observed a steady decrease of production of deuterated ammonia NH2D with sample temperature (from 60 degrees C to 350 degrees C).