LHC magnet quench detection by trend analysis of the pressure signal

CERN´s LHC is composed of thousands of superconductor magnets that may sometimes quench (lose suddenly their superconducting properties). This paper presents a method to detect magnet quenches from the pressure of the helium inside the magnets. The method detects slight deflexions on the pressure signal created by a magnet quench. The deflexion is recognized through a trend analysis of the pressure filtered first derivative, where a specific shape formed of two consecutives temporal episodes signs the presence of a quench. The method was tested on a database composed of 30 pressure signals, where a total of 94 quenches occurred during the measurements. The results were analysed through a ROC curve and showed that the method was able to detect 84% of the quenches with only one false alarm.