The 7-gap-resonator accelerator for the REX-ISOLDE project at CERN

The REX-ISOLDE experiment which is presently under construction at CERN is intended to investigate exotic, very neutron-rich, radioactive nuclei. A linear accelerator will deliver radioactive beams which are produced by the isotope separator ISOLDE, with energies between 0.85 and 2.2 MeV/u. The linac will consist of an RFQ accelerator, an interdigital H-structure (IH) and three 7-gap- resonators for variable final energy. The 7-gap-resonators are being operated at a frequency of f=101.28 MHz with a pulsed power of P=90 k W (duty cycle 1:10). After the fabrication of the power type resonators, high-power tests were performed in order to prove the design voltage of 1.74 MV at 90 kW rf power. These tests were carried out with a /sup 32/S beam and showed that the 7-gap-resonators exceed their design voltage; voltages between 1.77 and 1.88 MV were reached. In this paper the status of the 7-gap-resonator accelerator and the results of the high-power test are reported. (4 refs).