CERN Accelerating science

Article
Title	Concepts for the JLab Ampere-Class CW Cryomodule
Author(s)	Rimmer, Robert ; Daly, Edward ; Henry, James ; Hicks, William R ; Preble, Joseph P ; Stirbet, Mircea ; Wang, Haipeng ; Wilson, Katherine ; Wu, Genfa
Affiliation	(Jefferson Lab, Newport News, Virginia)
Publication	2005
In:	21st IEEE Particle Accelerator Conference, Knoxville, TN, USA, 16 - 20 May 2005, pp.3588
Subject category	Accelerators and Storage Rings
Abstract	We describe the concepts and developments underway at JLab as part of the program to develop a new CW cryomodule capable of transporting ampere-level beam currents in a compact FEL. Requirements include real-estate gradient of at least 10 MV/m and very strong HOM damping to push BBU thresholds up by two or more orders of magnitude compared to existing designs. Cavity shape, HOM damping, power couplers, tuners etc. are being designed and optimized for this application. Cavity considerations include a large iris for beam halo, low-RF losses, HOM frequencies and Q's, low peak surface fields, field flatness and microphonics. Module considerations include high packing factor, low static heat leak, image current heating of beam-line components, cost and maintainability. This module is being developed for the next generation ERL based high power FELs but may be useful for other applications such as electron cooling, electron-ion colliders, industrial processing etc.