The CMS Magnet Test and Cosmic Challenge (MTCC) Operational Experience and Lessons Learnt

The CMS detector is under construction for imminent operation at the LHC machine at CERN. The installation and commissioning of detector elements is being done in a surface hall before all the detector elements are lowered. The solenoidal magnet had to be tested before lowering, therefore the unique opportunity to operate all the sub-detectors and sub-systems together was exploited. This set of tests is called the MTCC Magnet Test and Cosmic Challenge. This article presents an overview of the results obtained when coherently running all CMS subsystems in a magnetic field, as well as operational and safety procedures.