[en] The 10 MV vertical single-ended Van de Graaff in the Nuclear Physics Laboratory at Oxford University has been converted to a folded tandem and is now in operation. Preparations for the conversion began four years ago and the accelerator was shut down for the changeover in July 1977. The first beam of ⁴He²⁺ ions was transmitted through the machine on September 7, 1978. Since then the test program has been devoted to measuring the properties of the transmitted beam and extending the operating voltage and beam current

[en] The history and development of the vertical injector Van de Graaff is summarized from its commissioning in 1965 to its present use as a source of intense α-particle beams of 9-10 MeV and of 40-50 MeV neon beams. The decision to convert the machine to a folded Tandem is justified in the light of the experimental programme and of the technical and economic factors involved. Some features of the folded Tandem design are discussed, the state of the conversion is reviewed and the performance goals are described

[en] The large vertical Van de Graaff in the Nuclear Physics Laboratory at Oxford University has been converted to a folded tandem with a rated terminal voltage of 10 MV. The new parts were designed and largely manufactured within the Laboratory and included the terminal, two negative ion sources, low energy and high energy beam transport and vacuum systems and a new control system. The conversion began in July 1977 and progressed so that experiments with the folded tandem began in January 1979. Excluding the value of manufacture and installation by Laboratory staff, the total cost of the conversion was 100 000 pound, the major items of outside manufacture being the 180⁰ magnet, the accelerator tubes and the serial data links. The main design features of the new accelerator are discussed as well as its performance during the first 18 months of operation. (orig.)