Measurements of 36Cl are traditionally performed on AMS facilities with accelerator voltages of 5 MV or more. The separation from isobaric 36S present in samples is performed in a gas ionisation detector measuring the stopping power of ions with energies of more than 40 MeV. Encouraged by the isobaric separation of 10Be from 10B at ion energies of less than 1 MeV, we looked now at the isobaric separation of 36Cl from 36S using a compact AMS system working at only 0.6 MV.
Negative chlorine ions were stripped to the 4+ charge state at an energy of 0.6 MeV at the compact ETH/PSI AMS facility. The ions with a final energy of about 3 MeV were detected in a gas ionisation detector optimised for low energies. A 40 nm thick silicon nitride entrance window and low noise signal processing electronics are used. A clear separation of the interfering 36S from 36Cl could be observed using the information of two energy loss signals from the detector. The 36S suppression was more than a factor 10. This is far better than what would be expected from calculations with the SRIM2003 simulation program. This example shows, that AMS at low energies is still not at its limit.
See more of Poster Session II
See more of The 10th International Conference on Accelerator Mass Spectrometry (September 5-10, 2005)