On the way to the series production of steel-concrete cores for the LEP dipole magnets

CERN has now launched the series production of the steel-concrete cores for the LEP dipole magnets after a three-year development programme during which 14 prototypes were built in collaboration with industry. This paper describes the mechanical, geometrical and magnetic characteristics of these cores and the fabrication techniques which have been developed. Particular emphasis is put on the following points: the controlled mixing of steel in order to reduce the field variations between cores; the influence of the thickness and of the pitch of the laminations on the field quality; and the composition and working conditions of the mortar in relation to the tolerances on core geometry