Author/Authors :
Valles، نويسنده , , N. and Liepe، نويسنده , , M. and Furuta، نويسنده , , F. and Gi، نويسنده , , M. and Gonnella، نويسنده , , D. and He، نويسنده , , Y. and Ho، نويسنده , , K. and Hoffstaetter، نويسنده , , G. and Klein، نويسنده , , D.S. and OʹConnell، نويسنده , , T. and Posen، نويسنده , , S. and Quigley، نويسنده , , P. and Sears، نويسنده , , J. R. Stedman، نويسنده , , G.Q. and Tigner، نويسنده , , M. and Veshcherevich، نويسنده , , V.، نويسنده ,
Abstract :
Future particle accelerators will require continuous wave operation of SRF cavities capable of supporting high beam currents. An example of this is the Energy Recovery Linac (ERL) at Cornell University, a next generation light source designed to run high currents (100 mA) with a high bunch repetition rate (1.3 GHz). Obtaining the beam emittance necessary to meet design specification requires strong damping of higher-order modes that can lead to beam breakup. We discuss the optimization and verification of the accelerating cavity. Next we show that an ERL constructed from the optimized cavity geometry – including realistic shape errors – can support beam currents in excess of 300 mA while still maintaining beam stability. A niobium prototype 7-cell cavity was fabricated and tested in a horizontal cryomodule. We show that the prototype cavity exceeds quality factor and gradient specifications of 2 × 10 10 at 16.2 MV/m at 1.8 K by 50%, reaching Q = ( 3.0 ± 0.3 ) × 10 10 . The prototype cavity also satisfies all design constraints and has a higher order mode spectrum consistent with the optimized shape geometry. At 1.6 K, the cavity set a record for quality factor of a multicell cavity installed in a horizontal cryomodule reaching Q = ( 6.1 ± 0.6 ) × 10 10 .
