REMARKS ON USE OF PERFLUOROPOLYETHER FLUIDS IN PARTICLE ACCELERATOR VACUUM-SYSTEMS

A systematic series of tests was performed to investigate the advantages of using standard cuts of perfluoropolyether fluids (Fomblin Y) as vacuum fluids for the pumpdown of ion source and particle accelerator vacuum systems. Vacua in the low 10** minus **3 and 10** minus **7 Torr ranges were obtained by a rotary and an unbaffled diffusion pump, respectively. A residual gas analysis shows the presence of high molecular weight fractions, up to M equals 240. This fact advises against their use in heavy ion sources and accelerating systems where electron exchange processes are highly dangerous. The absence of tar and sludge formations even under high intensity electron bombardment is a very important feature for their use in high intensity electron beam accelerators.