Gas mixing effect on Kr ion currents from an ECR ion source

Pure and different support gas-mixed krypton plasmas are produced using the 14.5 GHz all permanent-magnet based electron cyclotron resonance (ECR) ion source. The ions are extracted and the charge state distributions (CSDs) are studied. The H2, He, N2, O2, Ne, Ar, CH4 and CO2 gases are used as support gases. One of the support gases are mixed with Kr at several mixing ratios and its effect on the outputs currents of the Kr ions are studied. The total effective charge, as well as effective charges of Kr and mixing gas ions are calculated from the measured ion currents. The total ion loss rates are also calculated. The gases N2, O2, Ar and CO2 are found to exhibit better mixing effect in the enhancement of output of highly charged ions. The best enhancement in the output currents of Kr ions is observed in case of O2 as the mixing gas under certain conditions. To the best of our knowledge such a detail comparative study on the influence of mixing gas has not been reported so far for ECR ion-beam application.