Damping the {pi}-mode instability in the SLC damping rings with a passive cavity

Conference · Wed Jul 01 04:00:00 EDT 1992

OSTI ID:10166503

Chao, Y; Corredoura, P; Hill, A; Krejcik, P; Limberg, T; Minty, M; Nordby, M; Pedersen, F; Schwarz, H; Spence, W; Wilson, P

Operating the Stanford Linear Collider (SLC) at 120Hz repetition rate requires the presence of two bunches in both the electron and the positron damping ring. The {pi}-mode instability, a coupled bunch instability where the two bunches oscillate with a phase difference of 180{degrees}, had been observed in both rings with low current thresholds of 7{sup *}10{sup 9} particles per bunch. To avoid the instability, the RF system had to be operated in ways which in general reduced the cavity gap voltages and required constant operational attention. For the 1992 running cycle a passive cavity was installed and successfully tested. It is tuned to the frequency of the lower synchrotron oscillation sideband of an odd revolution harmonic. The impedance of the cavity then damps {pi}-mode oscillations very similar to the Robinson damping provided by the main RF cavities which damps O-mode synchrotron oscillations. In this report we describe the motivation and physical considerations that led to the final design parameters and the experience obtained from the performance of these cavities.

• Research Organization: Stanford Linear Accelerator Center, Menlo Park, CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00515
• OSTI ID: 10166503
• Report Number(s): SLAC-PUB--5868; CONF-920706--6; ON: DE92018153
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430200
430303
BEAM BUNCHING
BEAM DYNAMICS, FIELD CALCULATIONS, AND ION OPTICS
CAVITY RESONATORS
DESIGN
EXPERIMENTAL FACILITIES AND EQUIPMENT
INSTABILITY
LANDAU DAMPING
PERFORMANCE
RF SYSTEMS
STANFORD LINEAR COLLIDER
SYNCHROTRON OSCILLATIONS