36Cl measurements with a gas-filled magnet at 6 MV

The use of a gas-filled magnet (GFM) for Accelerator Mass Spectrometry (AMS) of Cl-36 is presented. We show that at a 6 MV Tandem accelerator a GFM provides sufficient suppression of S-36 while still maintaining a high Cl-36 efficiency. At 48 MeV (charge state 7 + ) we get a suppression factor of 200-400 of the GFM alone, together with the gas ionization chamber (GIC) we have a total suppression factor of 10(5). At this energy the acceptance of the GFM for Cl-36 is 75%, considering also the applied gating on the signals of the GIC the total counting efficiency is 65%. The use of the GFM provides a robust method for routine measurements of most Cl-36 samples. Stable conditions over several days of measurement time and consistent low blanks (Cl-36/Cl-33 < 10(-15)) can be achieved.