Ion optical design of the BRF-FNAL-SAIC-UW PET accelerator

Production of positron emitting radioactive isotopes ¹⁸F, ¹⁵O, ¹¹C and ¹³N for use in positron emission tomography is important for medical imaging. The present state of the production art is to use cyclotrons to accelerate deuterons to an energy range in the 10´s of MeV and impinge the deuterons on appropriate targets. An alternative approach is to use a cascade of RFQ´s to accelerate ³He ions to 10-MeV as the bombarding particles. Due to the lower background radiation, a ³ He accelerator requires far less shielding than a cyclotron, in addition to other advantages. This paper will discuss briefly the end to end ion optics design of an RFQ based ³He PET accelerator. Emphasis will be on the medium energy beam transport (MEBT) portion. The MEBT required a solution to the difficult problem of matching two RFQ´s while allowing room for a gas jet stripper. Our solution to this problem could be modified to allow a match between high power RFQ´s and linacs, a problem faced by several possible future accelerators