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[Assistant-faculty] seminar regarding the magnets of the LHC machine
Seminar
Bray building (2nd floor conference room)
Friday March 25th
11am
Speaker Dr. Ezio Todesco, CERN
It is well-known that superconducting magnets train, i.e., reach
successively higher and higher current after successive quenching. It is
general opinion that this training has mechanical origins, each quench
setting the magnet in a mechanically more stable configuration. In this
work we define a simple analytical one-dimensional model of stick-slip
motion of the magnet coil. We show how this model predicts that the
maximal magnet performance is asymptotically reached via a power law in
the number of quenches. We then consider the large statistical sample of
the training of individual dipoles are quadrupoles built for the CERN
Large Hadron Collider, showing that this power law is verified over a
large fraction of the training curves, i.e., in the range tending towards
large field and large number of quenches. The very initial part of the
training does not fit with this behaviour, but it can be described by a
generalization of the above model.