Chapter 7: Machine protection

Since the previous TDR version 0.1, the hardware development has made significant progress. The universal quench detection system, CLIQ and energy extraction system prototypes have been successfully produced and tested and first units have been successfully deployed and used in SM18. This progress is reflected in the Sections below and some of the previously retained options have therefore been removed. In addition, the development of the quench heater power supplies for the HL-LHC is well advanced, which is shown in the respective Section below. Chapter 6 was updated following the approval of layout changes to the triplet circuit and an additional Section on cold diodes was added, as they have been adopted within the HL-LHC baseline. Finally, two new sources for very fast failures have been identified and studied in the past years, which is presented in the Section on fast failures.