Production of stripper foils by laser ablation of carbon–boron sputter targets

The TRIUMF Applied Technology Group operates several high-power industrial cyclotrons for commercial radioisotope production. Two of these accelerators, TR30-1 and TR30-2, can deliver 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 approximately 2.0–3.0 μm thickness have been utilized to extract proton beams from these accelerators. IUMF Carbon Foil Laboratory uses pulsed laser deposition to manufacture DLC films in a wide thickness range (10 nm to ∼10 μm). It is known that the quality and the composition of the graphite sputter target used in the laser ablation process has a significant effect on the mechanical properties of the deposited film as well as its durability in ion beams. Encouraged by the findings of Sugai et al. [1], we investigated the production of stripper foils by laser ablation of graphite/boron composites as well as multilayer foils using pure graphite and boron targets.