Signal monitoring for the LHC - Development of an application for analyzing the main quadrupole busbar resistance

In 2008 a faulty interconnection between two superconducting dipole magnets in the LHC led to an arc. This released an massive energy stored in the magnetic field of the magnets and resulted in a considerable mechanical damage in the main dipole circuit. In order to prevent this scenario in the future, the quench protection system was extended and now monitors the busbar resistance. In addition, there are now several other safety measures put in place like the inspection of all superconducting circuits once a year during a Hardware Commissioning (HWC) powering test. However, each of those monitoring tools is working on its own and there is no way yet to correlate the analyzed data. This report will will briefly describe possible opportunities to find certain analogies between signals in order to calculate parameter trends and identify precursors of failure in certain components of the LHC. In order to do so, this paper will first give an overview of signal monitoring opportunities for the LHC and review the motivation for the signal monitoring project. It will then show how to use the machine learning stack to design a first draft of an application. This application will include an example of how a signal analysis scheme could look like. The scheme will consider the properties of the quadrupole busbar resistance. The system was developed so that it can be both expanded with other signals (such as main dipole circuit busbars) and it can be used as a template for different application which will also be mentioned in this paper. Overall this report is a short summary of my work together with Per Hagen, Zinour Charifoulline and Michał Maciejewski in the last three months. Together we set up a new project and contributed several proof-of-concepts to monitor the main dipole circuit across the LHC in the future.