Measurements of the Persistent Current Decay and Snapback Effect in Tevatron Dipole Magnets

Abstract

Abstract-A systematic study of the persistent current decay and snapback effect in the fields of Tevatron accelerator dipoles was performed at the Fermilab Magnet Test Facility (MTF). The decay and snapback were measured under a range of conditions including variations of the current ramp parameters and magnet operational history. The study has mostly focused on the dynamic behavior of the normal sextupole component. In addition, the paper presents the persistent current effects observed in the other allowed field harmonics as well. The results provide new information about the previously observed "excess" decay during the first several seconds of the sextupole decay during injection and the correlation between the snapback amplitude and its duration.

Field Quality Measurements of LARP <formula formulatype="inline"><tex Notation="TeX">$\hbox{Nb}_{3} \hbox{Sn}$</tex></formula> Magnet HQ02

“…Long-term dynamic effects in superconducting magnets are usually associated with the decay of the allowed field components at injection, which is followed by a subsequent snapback during the acceleration ramp [11], [12].…”

Field Quality Measurements in a Single-Aperture 11 T $ \hbox{Nb}_{3}\hbox{Sn}$ Demonstrator Dipole for LHC Upgrades

“…Long-term dynamic effects in superconducting magnets are usually associated with the decay of the allowed field components at injection, which is followed by a subsequent snapback during the acceleration ramp [14], [15].…”

Field Quality of the First LARP ${\rm Nb}_{3}{\rm Sn}$ 3.7 m-Long Quadrupole Model of LQ Series

“…This well-known phenomenon is usually associated with the decay and subsequent snapback of the allowed field components at injection [13], [14].…”