Accelerator tubes

The characteristics and performance of accelerator tubes required by the new generation of large tandem accelerators and by the upgrading of existing machines are summarized. Recent experiments on surface flashover of insulators in vacuum and on the control of surface charging are briefly reviewed current theories of the microdischarge process are examined and their relevance to the operation of UHV and conventional tubes is discussed. The role of microparticles, the evidence for their existence and their influence on breakdown is reported in the light of recent experiments using laser scattering and electron microscopy. Finally, current practice and achievements are compared with the data presented by Cranberg in 1952 and some conclusions are drawn about future progress and developments