Experimental studies of the afterglow mode with xenon in a CAPRICE ECRIS

At GSI the CAPRICE-type ECRIS delivers ion beams to the High Charge State Injector (HLI). Following the demand of high flexibility the ECRIS is operated either in cw mode for high duty cycle beams or in afterglow mode to provide low duty cycle beams for the Heavy Ion Synchrotron (SIS) at low repetition rates in the order of 1 pulse per second. Especially for high Z ions the afterglow mode can provide increased intensities with respect to cw mode in those charge states required for injection (A/q<8.5). Besides the required beam intensity major demands of accelerator injection are good long time stability and good pulse to pulse reproducibility of the ion beam. In order to find the best operating conditions for optimized afterglow performance systematic studies were performed with Xe-136, the heaviest stable rare gas isotope. Different rf pulse conditions (pulse length, repetition rate, pulse shape, duty cycle) were compared. The influence of the ion source parameters on the afterglow mode were studied in comparison to cw mode. (C) 2004 American Institute of Physics.