Reducing field emission in superconducting RF cavities for the next generation of particle accelerators

Heat treatment up to 1500 degrees C in an ultrahigh-vacuum furnace, along with processing of cavities and temperature mapping was used to suppress field emission and analyze emitter properties. In 27 tests of one-cell 1500-MHz fired accelerating cavities, on the average the accelerating field, E/sub acc/, increased to 24 MV/m (H/sub pk/=1250 Oe) from 13 MV/m with chemical treatment alone; the highest E/sub acc/ reached was 30.5 MV/m. Emitter properties, efficiency of He processing, and results of the exposure of well-processed RF surfaces to various media are also discussed.