Superconducting magnet

Under Quench (English: to quench: intercept, delete, erase ) is defined as the sudden transition of a superconductor from the superconducting to the normal conducting state due to exceeding the critical temperature. These arise due to the finite resistance now high voltages and a lot of heat, which can lead to the destruction of the superconductor to flashovers by the electrical insulation and in rare cases. The thereby vaporized refrigerant may blow due to the resulting pressure the cryostat vessel.

Especially dangerous is a quench in superconducting coils, since there the entire field energy is converted into heat abruptly with the collapse of superconductivity.

A quench can have several causes:

By coating the superconductor with a low- normal conductor layer or suitably rated copper wires surrounding negative consequences can be avoided or mitigated.

If some areas normal line to a short circuit is generated by the low-resistance layer. The heating is slower.

The cooling system is designed to dissipate this additional heat, the superconductor to return to its initial state again.

Continuous measurement of phase voltage can be automatically connected when a critical value is exceeded, with an outer additional resistor in which the excess electrical energy is converted into heat.

• Superconductivity