The electron-cloud instability in the arcs of the PEP-II positron ring

Conference · Sun Mar 01 04:00:00 EST 1998

OSTI ID:840024

Furman, Miguel A ^[1]; Lambertson, Glen R

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1. LBNL Library

We have applied our simulation code ''POSINST'' to evaluate, in linear approximation, the contribution to the growth rate of the electron-cloud instability (ECI) from the pumping sections and the dipole bending magnets in the arcs of the PEP-II positron ring. A key ingredient in our model is a detailed description of the secondary emission process off the TiN-coated chambers. Another important element is the analytic computation of the electric field produced by the beam, including the effects from surface charges. Space-charge forces of the electron cloud upon itself are also included, although these forces are negligible under nominal conditions. Bunch-length effects are optionally included by slicing the bunch into several kicks. We conclude that the growth rate is dominated by the pumping sections and scales linearly with the photoelectric yield Y'. For Y' = 1, our present estimate is in the range {approx} 1000-1300 s{sup -1}, depending upon the value of the photon reflectivity R. This is in the range controllable by the transverse feedback system. The contributions to the growth rate from other magnets and from other sections of the ring remain to be evaluated.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director. Office of Science. Office of High Energy Physics (US)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 840024
• Report Number(s): LBNL--41123; CBP Note - 246
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
BENDING
CLOUDS
DIPOLES
ELECTRIC FIELDS
ELECTRONS
FEEDBACK
INSTABILITY
MAGNETS
PHOTONS
POSITRONS
PUMPING
REFLECTIVITY
SECONDARY EMISSION
SIMULATION
SPACE CHARGE