Comparison of detector systems for the separation of 36Cl and 36S with a 3-MV tandem

Abstract: The possibility of detecting 36Cl for geological exposure dating has been explored for several years at VERA (the Vienna Environmental Research Accelerator). First results on real samples were obtained with an ionization chamber (developed at the ETH/PSI, Zürich, Switzerland) with two anodes. To improve the suppression of 36S, we equipped the ionization chamber with an exit window and added a Time-of-Flight (TOF) system with a double-sided silicon strip detector (50×50mm2) as stop detector. We optimized the TOF setup by using silicon nitride foils to reduce scattering tails in the energy spectra. At 3MV terminal voltage, corresponding to a particle energy of 24MeV of 36Cl7+, we achieved a 36S7+-suppression of 21,500 (50% 36Cl-detector-efficiency). [Copyright &y& Elsevier]