3 MV accelerator mass spectrometry measurements of 36Cl using the Isobar Separator for Anions

A second low-energy injection line containing the Isobar Separator for Anions (ISA), a radiofrequency quadrupole reaction cell system, was installed on the 3 MV tandem accelerator system at the A. E. Lalonde (AEL) accelerator mass spectrometry (AMS) Laboratory. The suppression of 36 S via anion-gas reaction with NO 2 was evaluated for measurements of 36 Cl reference materials and a dilution series, using a 3 MV AMS system. The dilution series, with 36 Cl/Cl ratios ranging from 10 -11 to 10 -15 , were measured in comparison with external measurement. 36 Cl/Cl blank levels of (7 ± 4) x10 -15 were reached. While ISA-AMS is not currently able to achieve sufficient separation for most 36 Cl applications, these measurements show progress towards routine measurement of 36 Cl and demonstrate the steps required to validate such measurements on lower energy AMS systems. • 3 MV AMS and a radiofrequency quadrupole reaction cell were used to measure 36 Cl. • The isobar 36 S - was suppressed by 7 orders of magnitude using reactions with NO 2 . • Dilutions series with 36 Cl/Cl ratios ranging from 10 -11 to 10 -15 and a blank level of 7 x10 -15 were measured. • Progress has been made towards using the Isobar Separator for Anions to the routine measurement of 36 Cl on lower energy AMS systems.