Design Parameters for a CESRc Anti-Solenoid
25 March 2005
J.A.Crittenden
Preliminary design parameters and field calculations for two CLEO-solenoid-compensating anti-solenoids are presented below. A summary of investigations of the beam optics and dynamics which are motivating consideration of this compensation strategy can be found here.
The sources used for these design considerations are this optical design, discussions with Richard Ehrlich, the quote for a superconducting coil design from American Magnetics, Inc. dated 16 March 2005, and the yoke design for two anti-solenoids built for CESR in 1978 which were never used.
The available length available for each of these magnets is 105 cm. The beam-pipe
radius in this region is 3 inches. The coil is 60 cm long and extends in
radius from 3.5 inches to 4.0 inches. The operating current is specified
by American Magnetics to be 180 A. The current necessary
for a field integral of 1.7 Tesla-meters is 1.3M Amp-turns, which
corresponds to 740 turns in the American Magnetics design.
The yoke consists of an iron cylinder of inner diameter of 12 inches, 2 inches
thick. This would be warm, surrounding the cryostat. No provision for
a helium pipe has yet been made. Iron endcaps 3 inches thick are included,
and bring the total weight of the iron to 545 kg. The total length is 93 cm.
Characteristics of the field are shown below. A field table is
here.
The longitudinal component of the field as a function of longitudinal position.
The peak field is 2.7 Tesla.
The magnitude of the fringe field on the beam axis. The magnet ends at 46.5 cm,
where the field has decreased to less than 1 kG.
The magnitude of the fringe field
as a function of distance from the beam axis
about 60 cm from the end of the magnet. It is about 50 G, falling off slowly.
The magnitude of the fringe field along the outside of the magnet, 38 cm from
the beam-line. The outer radius of the yoke is about 20 cm.
The field reaches a maximum of about 160 G near the end of the yoke.
Creation date: 03/25/05.