COMMISSIONING OF THE LEBT OF PIAVE AND THE ALICE ION SOURCE EMITTANCE MEASUREMENT

The relatively long low energy beam transport (LEBT) line joining the ion source high voltage platform and the first superconductive RFQ PIAVE is described, summarising design choice and describing related beam experiments; PIAVE will inject beams into the ALPI linac. In particular, the beam line has to cope with fluctuation in platform voltage (against which was made achromatic ) and the ion source noise, and has to match the beam to RFQ acceptance. The beam line is formed by a slanted U-bend, on a rigid 7 m long frame, followed by a long straight path where four large aperture quadruple doublets and a buncher allow the to prepare the RFQ nominal beam conditions. A beam emittance detector is placed at RFQ location, to monitor both the ion source operation, its apparent emittance and the beam line behaviour, so to ensure the transverse matching to RFQ acceptance. First experimental result and operating experience with argon and xenon test beams are described, showing a good emittance and excellent transmission.