100% Duty Factor RFQ Linac Systems at CRNL

An RFQ linac operating at 100% duty factor (cw) and high currents is required for an accelerator breeder. Two high power structures are being built as part of the RFQ development program. Firstly, a copper 270 MHz "sparker" cavity with RFQ geometry is being tested to determine cw field breakdown levels and conditioning characteristics. The design and status of the "sparker" are presented. Secondly, a 270 MHz cw RFQ linac (RFQ1) is being designed to accelerate a nominal 75 ¿A from 50 to 600 keV, to study beam quality and stability as well as resonator field tuning and leveling requirements under conditions of high beam loss at high average power. For example, the combination of cw operation and restricted space at the entrance require new approaches in end terminations and tuners. The status of RFQ1 is presented and design innovations outlined.