RFQ Linac Structure Developments at CRNL

Modeling studies of RFQs for a 300 mA cw proton accelerator are continuing at CRNL. Initially, low power models of the four-vane structure with standard end terminations were extensively investigated. Later, results of simple rf dipole experiments led to studies of two new RFQ termination schemes, the double dipole (in which two opposing vanes were shorted at both ends) and the folded dipole (in which one set of opposing vanes was shorted at one end, the other vane set shorted at the other end). Various end tuner configurations were also tested, including radial end tuners and Bourdon tube mechanisms for remote positioning. Finally, a versatile low power RFQ model has been built to study rf properties with reproduci bl e vane geometry.