Improved 26Al and 10Be cathode performance and data analysis at KIST

Abstract

Addition of a metal powder interface between solid metal cathode and sample powder was investigated for 26Al and 10Be analysis by accelerator mass spectrometry (AMS). Cathode quality and consistency improved, leading to more intense, stable and longer-lived ion beam currents, while cathode matrix sensitivity to powder fineness, homogeneity and precipitate to metal powder mixing ratios was reduced. Now, ratios of 1:0.75？2 for Al2O3 + Ag in Cu cathodes and 1:0.9？4 for BeO + Nb in Al or Cu cathodes are optimal. Furthermore, a survey of sputter energies showed that 5 keV？6 keV greatly increases cathode life, current stability, and cathode consumption efficiency for both BeO and Al2O3 as opposed to the widely used 7 keV for High Voltage Engineering SO110 ion sources. Finally, some data flagging criteria that have recently been incorporated into the 26Al and 10Be internal data analysis software are explained.