Prompt gamma-ray analysis (PGA) of meteorite samples, with emphasis on thedetermination of Si

Neutron-induced prompt gamma-ray analysis (PGA) was applied to seven meteor ite samples (Allende, Zagami, Acfer 209, ALH77005, ALH84001, EET79001 and N eagari). Samples were irradiated in both the thermal neutron and the cold n eutron guided beams of JRR-3M at JAERI. Multiple samples of an Allende stan dard powder were analyzed for Si using two different methods: (1) the compa rison method, using a Si standard, and (2) the mono-standard method, using Fe as an internal reference element. The Si concentrations determined by th ese two methods are in good agreement with literature values. The analytica l sensitivity for Si using the cold neutron guided beam is -14.3x higher th an that for the thermal neutron guided beam. Other elements determined (B, Ca, Ti and S) also showed higher sensitivities using the cold neutron beam. The other meteorites studied showed some anomalous B and S values likely d ue to the effects of terrestrial weathering/contamination.