what exactly is done during precycling?

[chriwi]

Did anyone here find a good description of the precycling of the LHC?

[serych]

IMHO precycling = cycling, which is process to reset magnetic memory of the superconducting magnets. They keep tiny piece of the history of their magnetization in the hysteresis curves if I can understand it well.
That's why for the perfect reproducibility of the next settings it is necessary to magnetize them with small reverse currents (depending on magnetization in past cycle) to reset this hysteresis.

Jakub

[chriwi]

That soundslike the demagnetisation of a CTR-tube in an old TV . But I understand they have the same kind of problem here.

[Tau]

This may be way too detailed, but basically it says: "You're right, it is like an old CRT".
http://cdsweb.cern.ch/record/1199585/fi ... 09-007.pdf

[chriwi]

Thanks Tau,

thats what I was looking for.

Thanksalso to serych for the brief description.