Carbon–silicon stripper foils

TRIUMF operates several high power industrial cyclotrons for the commercial production of isotopes for radiological diagnostics and therapy. Two of these accelerators, TR30-1 and TR30-2, are capable of delivering H− beams of 30 MeV and beam currents in excess of 1000 μA. For many years, in-house produced diamond-like carbon (DLC) foils of various compositions have been utilized to extract proton beams from these cyclotrons (Zeisler and Jaggi, 2008) [1]. IUMF Carbon Foil Laboratory, now incorporated as MicromatterTM, uses pulsed laser deposition to fabricate DLC films in a wide thickness range (from 10 nm to ∼10 μm). More recently, we reported the production of DLC foils containing boron (Zeisler and Jaggi, 2010) [2]. Carbon–boron multilayer foils have outstanding mechanical stability and show an extended lifetime in high intensity proton beams. In an attempt to further enhance the quality of our beam strippers, we investigated the production of carbon–silicon multilayer foils.