Every so often the source of the lead ions has to be replaced. A small sliver of solid isotopically pure 208Pb is placed in a ceramic crucible that sits in an “oven” casing at the end of a metal rod. The metal is heated to around 800°C and ionized to become plasma. Ions are then extracted from the plasma and accelerated. Depending on the beam intensity, in stable running the accelerator chain consumes about 2 mg of lead every hour – a tiny amount, but 10 g costs some SwFr12,000 (approx US$13,000). In this image the position of the oven is being measured inside the source for Linac 3.
