Characterization of lunar nitrogen components

Rocks of known and disparate cosmic-ray ages are analyzed to find the spallation production rate of N-15. A soil breccia of known formation age was analyzed for its bearing on the antiquity of the isotopically light component. Further stepwise heating analysis of soils shed further light on occurrences of the components. Lunar soil samples were etched slightly by fluorine, revealing significant differences in isotopic ratios between carbon on grain surfaces and bulk carbon; the surface carbon is not retained during agglutinate formation. Etching revealed that about 25% of the total nitrogen resides on the surface of grains; the nitrogen is isotopically heavy. Etching also revealed about 50% of helium in soils residing below the readily etched outermost 1% of soil grain surfaces.