Description of new vacuum chamber correction concept

Conference · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6331670

Danby, G T; Jackson, J W

For rapid cycled accelerators eddy currents induced in vacuum chambers (VC) are typically the dominant source of systematic and random field aberrations. Complex thin wall VC are expensive and delicate where bakeout is required, as in the AGS Booster under construction. Thick wall VC are rugged and economical but produce large eddy currents. A ''Self-Correction'' concept has been developed and tested which corrects automatically by transformer action, even for variable /dot B/ cycles. Coils attached to the outside of the VC cancel eddy current aberrations over the entire ''good field'' aperture. The (inexpensive) correction coils follow the local contour of the VC, so large transverse VC movements are tolerated; both the aberrations and their corrections have the same displaced coordinates. Experimental results are presented for Booster correction coil designs demonstrating both self-correction and excitation by a separate power supply. Analytic results applicable to the Booster and other fast cycling accelerators are discussed. The eddy current field aberrations induced in a pre-production full size vacuum chamber inserted in an AGS Booster dipole have been successfully eliminated by the ''self correction'' coils attached to its surface. The voltage induced in a two-turns per pole ''back leg'' winding is sufficient to supply the necessary current through the correction winding. A nichrome wire attached in series provides adjustable resistance for current control. 2 refs., 7 figs.

• Research Organization: Brookhaven National Lab., Upton, NY (USA)
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 6331670
• Report Number(s): BNL-41856; CONF-890335-76; ON: DE89011251
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430200* -- Particle Accelerators-- Beam Dynamics
Field Calculations
& Ion Optics
ACCELERATORS
BROOKHAVEN AGS
CONTAINERS
CORRECTIONS
CURRENTS
CYCLIC ACCELERATORS
DIPOLES
EDDY CURRENTS
ELECTRIC COILS
ELECTRIC CURRENTS
ELECTRICAL EQUIPMENT
EQUIPMENT
MAGNET COILS
MAGNETIC DIPOLES
MAGNETIC FIELDS
MULTIPOLES
PARTICLE BOOSTERS
PRESSURE VESSELS
SYNCHROTRONS