Initial tests of 26Al fluoride target matrix on MILEA AMS system

Abstract

In this study, the possibility of using a superhalogenide ion AlF4- extracted from Na3AlF6 based target materials for 26Al/27Al measurements by Accelerator Mass Spectrometry (AMS) was investigated. Determination of 26Al by usual mass spectrometric methods is generally hampered by the presence of the isobar 26Mg. However, the AMS method enables significant suppression of this interference, particularly by negative ion formation. After initial current tests in a caesium sputtering ion source of the Tandetron system, performance of the fluoride materials was analysed on the MILEA AMS system at ETH Zürich. The AlF4- current was used to evaluate the performance of the respective samples. Additives as PbF2 were tested to increase the extracted ion currents and samples containing MgF2 were used to investigate the presence of isobaric ions. Subsequently, the ionization efficiency of AlF4- was determined by recording the 27Al2+ current on the high energy side and the signals of 26Al2+ were investigated with the gas ionization detector.