Methods for Measuring and Controlling Beam Breakup in High Current ERLS

Conference · Sun Aug 01 04:00:00 EDT 2004

OSTI ID:827977

Tennant, Christ; Jordan, Kevin; Pozdeyev, E; Rimmer, Robert; Wang, Haipeng; Simrock, Stefen

It is well known that high current Energy Recovery Linacs (ERL) utilizing superconducting cavities are susceptible to a regenerative type of beam breakup (BBU). The BBU instability is caused by the high impedance transverse deflecting higher-order modes (HOMs) of the cavities. This multipass, multibunch instability has been observed at Jefferson Laboratory's FEL Upgrade driver. Some preliminary measurements are presented. To combat the harmful effects of a particularly dangerous mode, two methods of directly damping HOMs through the cavity HOM couplers were demonstrated. In an effort to suppress the BBU in the presence of multiple, dangerous HOMs, a conceptual design for an injector beam-based transverse feedback system has been developed. By implementing beam-based feedback, the threshold for instability can be increased substantially.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (US)
• Sponsoring Organization: USDOE Office of Energy Research (ER) (US)
• DOE Contract Number: AC05-84ER40150
• OSTI ID: 827977
• Report Number(s): JLAB-ACC-04-262; DOE/ER/40150-2834
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
CAVITIES
DAMPING
DESIGN
ENERGY RECOVERY
FEEDBACK
IMPEDANCE
INSTABILITY
LINEAR ACCELERATORS