THE RFQ-ACCELERATOR FOR THE HEIDELBERG HIGH-CURRENT INJECTOR

At the MPI fur Kernphysik, a new type of accelerator is under construc tion which consists of a CHORDIS ion source [1], two RFQ and eight 7-g ap resonators [2]. The High Current Injector will deliver 1-3 orders o f magnitude higher intensities in comparison to the existing tandem-po staccelerator combination. The RFQ is designed to accelerate ions with a minimum charge to mass ratio of q/m = 1:9 up to an energy of 0.478 MeV/u. Both resonators operate at a frequency of 108.48 MHz with a pul sed power of 90 kW (25% duty factor (DF)). By means of an optimizing a lgorithm, it was possible to lower the electrode voltage of the RFQ-ac celerator from 71 kV to 60 kV maintaining a slightly reduced final ene rgy and a particle transmission of about 80% with ion currents of 10 m A [3]. A new electrode profile was developed in order to combine suffi cient cooling with good mechanical stability. Moreover the fabrication process of the RFQ-stems and the electrodes were simplified and optim ized. Both resonators are tuned and tested with low level measurements and under high power with a H-2(+)-ion beam. (C) 1998 Elsevier Scienc e B.V.