Cable Magnetization Effects in the LHC Main Dipole Magnets

Several short (1 m) and long (10 m) dipole models have been tested within the scope of the on-going R&D programme for LHC at CERN. We report here the results of measurements of field quality, focussing on the contribution of persistent current magnetization. We show that measurements of the dependence of allowed harmonics on magnetic field at 1.8 K can be computed with reasonable accuracy. The calculation is based on a model of the filament magnetization adjusted to fit available strand data. Low field measurements of the first allowed harmonics, sextupole and decapole, correlate satisfactorily with the filament diameter and the scaling obtained from the simulation program.

[1]  R. Wolf,et al.  Persistent currents in LHC magnets , 1992 .

[2]  L. Walckiers,et al.  Field errors decay and "snap-back" in LHC model dipoles , 1997, IEEE Transactions on Applied Superconductivity.

[3]  N. Siegel.  Status of the Large Hadron Collider and magnet program , 1997, IEEE Transactions on Applied Superconductivity.

[4]  Peter Schmüser,et al.  Superconducting Accelerator Magnets , 1996 .

[5]  A. Prodell,et al.  Current dependence of harmonic field coefficients of 5-cm-aperture, 15-m-long SSC dipole magnet prototypes , 1993, IEEE Transactions on Applied Superconductivity.

[6]  A. Prodell,et al.  The magnet system of the Relativistic Heavy Ion Collider (RHIC) , 1996 .

[7]  M. Syphers,et al.  Time-varying sextupole corrections during the Tevatron ramp , 1989, Proceedings of the 1989 IEEE Particle Accelerator Conference, . 'Accelerator Science and Technology.