Status of ALPI and Related Developments of Superconducting Structures

This talk treats of three main topics, namely: I) the status of the Superconducting Linac ALPI; II) the strategies put into action in order to push up the resonator performances; III) the design and prototype work directed to the construction of a new positive ion injector for our Linac. Since the beginning of 1995 several beams have been successfully accelerated with the ALPI Linac injected by the XTU-Tandem, especially in the medium-light mass region using Pb-plated and Nb-coated resonators. The machine, warmed up several times since 1993, does not exhibit significant Q-degradation at high field. The difficulty of transferring the high Q-performances of the Nb based resonators from test bench conditions into the machine environment is discussed with some detail. The most challenging work now under way in Legnaro is the construction of two Superconducting RFQ’s which will boost the velocity of the ions produced by an ECR source and pre-accelerated through a 350 kV platform from beta 0.01 up to beta 0.035. The design work and the key choices of the manufacturing process will be presented.