The Superconducting Magnet Division supplied 1740 magnetic
elements, in 888 cryostats, for the RHIC facility at BNL
(http://www.bnl.gov/rhic/). Of these,
780 magnetic elements were manufactured by Northrop-Grumman (Bethpage, NY) and
360 were made by Everson Electric (Bethlehem, PA). The magnets made in industry used designs developed at BNL. The first cooldown of the magnets for the
RHIC engineering run was in 1999. Since
then, the magnets have operated very reliably.
The magnets provide modest field (3.45 Teslas in the arc
dipoles) in a cost-effective design.
Key features in the principal bending and focusing magnets include the
use of NbTi Rutherford cable, a single-layer coil, and cold iron as both yoke
and collar. The magnets operate in
forced-flow helium at a nominal temperature of 4.6 K. The arc dipoles have 8 cm aperture and 9.7 m length.
Arc
dipole coil and yoke, with magnetic flux lines
Arc dipole cold mass
Arc dipole magnet
To limit the heat leak at the leads, the coils of the
correction elements use a single strand of NbTi wire. The stronger correctors, such as the sextupoles, have a
superferric design and modular coils to achieve the needed field strength. The remaining elements, such as the trim
dipoles, were made using an integrated CAD-CAM method. 
sextupole
4 layer corrector
The designs of the IR magnets are extensions of those used
in the 8 cm arc magnets. The 10 cm
insertion dipoles use the same cable design as the 8 cm dipoles, with a larger
yoke. The design of the strand and cable was modified in order to
meet the requirements of the 13 cm insertion quadrupoles and the 18 cm
dipoles. Further, to contain the higher
Lorentz forces, the coils of the 18 cm dipole are clamped both by stainless
steel collars and by the yoke. The same
manufacturing methods were used for the 13 cm correctors as for the 8 cm
correctors.
D0
DX
IR Quad
A summary of the magnet construction and test results is
available at http://www.bnl.gov/magnets/magnet_files/Publications/MDN-610-20.pdf
For more information contact
Peter Wanderer
