CHIME dating under low accelerating voltage condition

Abstract

CHIME dating under lower accelerating voltage makes X-ray generation volume smaller than usual analytical conditions (15 - 25 kV accelerating voltage) in electron probe microanalysis. CHIME dating of uranite and thorianite was performerd to evaluate quality of quantitative EPMA of U, Th and Pb under low accelerating voltage condition. The uraninite sample yields 1124 Ma at 15kV and 1122 Ma at 5kV, respectively. The thorianite sample yields 558 Ma at 15kV and 555 Ma at 5kV, respectively. Those results show that it is possible to perform EPMA CHIME dating with low accelerating voltage.