DESIGN AND CONSTRUCTION OF A ONE-METER MODEL OF THE 73 MM APERTURE QUADRUPOLE FOR THE LHC LOW-BETA INSERTIONS

In order to achieve high field quality and low current rating of the 2 50 T/m quadrupoles for the LHC low-beta insertions, a design based on a graded four-layer coil with an aperture of 70 mm, wound from NbTi co nductor cooled at 1.8 K, has been proposed. Its mechanical structure i s based on the collar-spacer concept, where a thin collar serves for c oil assembly only. The iron yoke has both important magnetic and struc tural functions, since the magnetic forces are taken by the rigidity o f the iron lamination pack. The coil and cable parameters are derived for this particular structure, and the results of the structural analy sis of the magnet are presented. A one-metre model of the quadrupole i s presently under construction; its features are described and some in itial cable tests reported.