Commissioning of the Machine Protection Systems of the Large Hadron Collider Following its First Long Shutdown

Abstract

During the first long shutdown of the Large Hadron Collider (LHC) extending for more than 18 months, most Machine Protection Systems (MPS) have undergone significant changes, and upgrades. A full re-commissioning of the MPS was performed at the end of the shutdown and during the LHC beam commissioning in 2015. To verify the correct functioning of all protection-relevant systems with beam, a step-wise intensity ramp-up was performed, reaching at the end of 2015 a record stored beam energy of� 280MJ per beam, nearly 80% of the value in the design report. Thiscontributionsummarizesthe results of the MPS commissioning, the intensity ramp-up and the continuous follow-up during operation, focusing mainly on near misses and false triggers and their proposed mitigations. A strategy to minimize risks during machine development periods for future operation of the LHC, when the protection parameters are modified for several tests, is discussed. The machine protection strategy for the LHC run in 2016 is presented.