Mechanical Technologies for PIGMI

PIGMI (Pion Generator for Medical Irradiations) is a compact linear proton accelerator designed for a hospital environment. The prototype of the low energy section of PIGMI has been designed and is being fabricated at the Los Alamos Scientific Laboratory. It is an accelerator design which makes use of several advanced or innovative technologies. The PIGMI Prototype consists of a 250 keV injector, a double harmonic buncher, a tape-wound 13 kG solenoid magnet, and four accelerator tanks with a total of 63 drift tubes of which 18 contain strong focusing quadrupoles of permanent magnets. The accelerator tanks are mild steel, copper-plated using a bright acid leveling technique. Drift tubes are stainless steel, fabricated using electron beam welding, shaped in a lathe and then copper plated. Drift tubes loaded with permanent magnets are sealed using laser welding. The samarium cobalt magnets are shaped by cutting and grinding techniques developed at Los Alamos.