A scaling law for the snapback in Superconducting accelerator magnets

• Published in: IEEE transactions on applied superconductivity Vol. 15; no. 2; pp. 1217 - 1220
• Main Authors: Ambrosio, G., Bauer, P., Bottura, L., Haverkamp, M., Pieloni, T., Sanfilippo, S., Velev, G.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.06.2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acceleration; Accelerator magnets; Accelerators; Analogies; Applied sciences; Bending; Colliding beam accelerators; Colliding beam devices; Current distribution; Decay; decay and snapback; Dipoles; Electrical engineering. Electrical power engineering; Electromagnets; Exact sciences and technology; Large Hadron Collider; Magnetization; magnetization reversal; Magnets; Particle accelerators; Particle beams; Ramps; Structural beams; superconducting accelerator magnets; Superconducting magnets; Superconductivity; Various equipment and components; Magnetization reversal; CERN LHC; Superconducting magnet; Scaling law; superconducting accelerator magnets; decay and snapback; Dipole; Current distribution; Accelerator magnets
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2005.849535

The decay of the sextupole component in the bending dipoles during injection and the subsequent snapback at the start of beam acceleration are issues of common concern for all superconducting colliders built or in construction. Recent studies performed on LHC and Tevatron dipole magnets revealed many similarities in the snapback characteristics. Some are expected, e.g. the effect of operational history. One particular similarity, however, is striking and is the subject of this paper. It appears that there is a simple linear relation between the amount of sextupole drift during the decay and the magnet current (or field) change during the ramp required to resolve the snapback. It is surprising that the linear correlation between snapback amplitude and snapback field holds very well for all magnets of the same family (e.g. Tevatron or LHC dipoles). In this paper we present the data collected to date and discuss a simple theory that explains the scaling found.