Singly-charged heavy-ion beam studies on a 12 MHz RFQ

Detailed experimental measurements of singly-charged ¹³²Xe and ⁸⁴Kr beams accelerated through the ANL 12 MHz RFQ for inter-vane voltages up to the design value of 100 kV have been performed. As part of an injector to a RIB linac for RIA (Rare Isotope Accelerator) the RFQ would accelerate low energy, low charge-to-mass ratio ion beams with high efficiency (ie. CW operation) while simultaneously introducing negligible transverse or longitudinal emittance growth. We will present results of a series of measurements using ¹³²Xe and ⁸⁴Kr beams ranging in energy from 220 to 450 keV injected into the RFQ using the ANL 4 MV Dynamitron and a recently added RF chopper used to simulate pre-bunched beams. Small beam chop widths of a few nanoseconds at the entrance permit detailed tests of the RFQ acceptance and emittance properties. Measured ¹³²Xe and ⁸⁴Kr energies at the RFQ exit are in agreement with model calculations. The long term thermal stability of the RFQ at the highest inter-vane voltages (~100 kV) are discussed