During the ramping-up of current in the main dipole circuit at the nominal rate of 10 A/s, a resistive zone developed leading in less than one second to a resistive voltage of 1 V at 9 kA. The power supply, unable to maintain the current ramp, tripped off and the energy discharge switch opened, inserting dump resistors into the circuit to produce a fast current decrease. In this sequence of events, the quench detection, power converter and energy discharge systems behaved as expected. Prior to this fast discharge, it is certain that a magnet quench can be excluded as the cause of the initial event. During the discharge, many magnet quenches were triggered automatically in the arc and the helium from their cold masses was recovered through the self actuated relief valves. 2. Within one second, an electrical arc developed, puncturing the helium enclosure and leading to a release of helium into the insulation vacuum of the cryostat. After 3 and 4 seconds, the beam vacuum also degraded in beam pipes 2 and 1, respectively. Then the insulation vacuum started to degrade in the two neighbouring subsectors.
Een nog gedetailleerd beschrijving van de dingen die 19 september fout gingen is hier te vinden. Oorzaak van de lek is dus kennelijk geen magneetquench, zoals men eerst dacht. Nou nog hopen dat men er goede lessen uit kan trekken en dat dit soort dingen niet nog eens gebeuren. Bron: CERN.