Pre-compression of bunch length in the SLC damping rings

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

OSTI ID:10166471

Decker, F J; Limberg, T; Turner, J

After extraction, the damping ring (DR) bunch length is compressed in the RTL (Ring-To-Linac) transport line to achieve the desired linac bunch length. For this, an energy spread is induced proportional to the DR bunch length, producing large, aperture filling, horizontal beam sizes in the dispersive regions of the RTL. There, nonlinear magnetic fields and wakefields cause higher order dispersion at the beginning of the linac, which increases the effective beam emittance. More important, in the presence of DR extraction jitter this causes linac launch jitter which makes linac operation unstable at high currents. A precompression of the DR bunch length would reduce the horizontal beam size in the RTL and thus relieve the problems mentioned above. It can be achieved by a modulation of the damping ring RF amplitude with a so-called ``bunch muncher`` shortly before extraction. A principle limitation is the inevitable increase in energy spread of the extracted bunch which sets the lower limit for the achievable bunch length in the linac. For SLC parameters the possible reduction in DR bunch length is about 35%. The routinely operation of the ``bunch muncher`` consists of two ``munches,`` cancelling the effect of the beam loading and keeping the extraction phase unchanged.

• 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: 10166471
• Report Number(s): SLAC-PUB--5871; CONF-920706--7; ON: DE92018154
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430200
BEAM BUNCHING
BEAM DYNAMICS, FIELD CALCULATIONS, AND ION OPTICS
BEAM EMITTANCE
BEAM TRANSPORT
COMPUTERIZED SIMULATION
DAMPING
PHASE SPACE
STANFORD LINEAR COLLIDER
STREAK CAMERAS