Electromagnetic field modeling and ion optics calculations for a continuous-flow AMS system

A continuous-flow 14C AMS (CFAMS) system is under construction at the NOSAMS facility. This system is based on a NEC Model 1.5SDH-1 0.5 MV Pelletron accelerator and will utilize a combination of a microwave ion source (MIS) and a charge exchange canal (CXC) to produce negative carbon ions from a continuously flowing stream of CO2 gas. For high-efficiency transmission of the large emittance, large energy-spread beam from the ion source unit, a large-acceptance and energy-achromatic injector consisting of a 45o electrostatic spherical analyzer (ESA) and a 90o double-focusing magnet has been designed. The 45o ESA is rotatable to accommodate a 134-sample MC-SNICS as a second ion source. The high-energy achromat (90o double focusing magnet and 90o ESA) has also been customized for large acceptance. Electromagnetic field modeling and ion optics calculations of the beamline were done with Infolytica MagNet, ElecNet, and Trajectory Evaluator. PBGUNS and SIMION were used for the modeling of ion source unit