Improved 36Cl AMS at 5MV

Small changes to our ion source and gas ionization detector have significantly improved Cl measurement by reducing source memory and increasing interference rejection. Gas stripped low energy 30MeV 36Cl5+ ions are still efficiently transported to the detector but 36S vs. 36Cl separation is improved by an order of magnitude. Accordingly 36Cl/Cl background is <10−15 before additional interference correction that is also newly automated. 35Cl− currents have increased to 30μA and 36Cl/Cl inter-cathode repeatability is 3%.