M. Pabst, K. Bongardt (Forschungszentrum Juelich GmbH, Germany)
For the high energy part of the ESS linear accelerator complex a superconducting (sc) option is presented. The main parameters of this linac are 700 MHz, a final energy of 1.334 GeV and 107 mA beam current. The input energy should be above 120 MeV in order to start with sc elliptical cavities with a beta greater than 0.5. At least three sections with different beta are needed to accelerate the beam up to the final energy. Not more than 6 cells per cavity should be used in order to keep the resulting phase slippage within acceptable limits. The accelerating gradient and the section length have to be adjusted keeping the zero current tune below 90 deg. Beam dynamical results for various designs of the ESS sc linac are presented. Fully 3d multiparticle simulations are carried through to look at the effect of phase slippage in indiviual cavities and the mismatch between different sections. Special emphasis is put on reducing the resulting halo formation in order to fulfill the constraints for loss free injection into the ESS compressor rings.
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