An rf driven ion source has been developed and tested at LBL for positive hydrogen ion production. Studies of this new source on ion species and current densities for a dc arc discharge are made in the 60‐kV PSI ion source test stand and the results compared with those obtained using the rf discharge. This source, using both discharge modes, will be installed in the PSI Cockcroft–Walton preinjector to increase the 870‐keV dc proton beam intensity from the present 8–10 mA operation to about 25 mA.