Experience with ISOLDE molten metal targets at the CERN PS-Booster

By moving the ISOLDE mass separators from the 600 MeV Synchrocyclotron (SC) to the 1 GeV-Booster Synchrotron the instantaneous energy density of the proton beam went up by 3 orders of magnitude. Sixteen molten targets and ion-source units have been used under pulsed proton beam conditions at ISOLDE between 1991 and 1995 and the development of the SC-units to match these requirements is described. Sets of baffles have been designed. Installed in the transfer lines which link the targets and the ion-sources they prevent splashes of the molten metals to flow into the ion sources. The liquid metal containment has been modified so that the electron beam welds are no longer in contact with the melt. A pyrocarbon disk inserted behind the proton beam obtained by spatial defocusing and time staggered extraction allowed to reduce the shock effect of the pulsed proton beam. (author) 7 figs., 8 refs