Measured and calculated pressure in the transverse field focusing (TFF) matching/pumping section of a negative ion beamline

A negative ion based neutral beam injection system is under development as proof-of-principle demonstration of a radiation-hardened beamline. The beamline consists of a source, a pre-accelerator, a matching/pumping (M/P) section, and an accelerator. The design of the M/P section was done with the aid of a two dimensional Monte Carlo computer code which was used to calculate the pressure along the beam path. The calculated and measured pressures are presented for several locations in the M/P section. 4 refs., 4 figs., (LEW)