Chapter 1: High Luminosity Large Hadron Collider HL-LHC

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a newenergy frontier for exploration in 2010, it has gathered a global user community of about 7,000 scientists work-ing in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. Tosustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase itsinstantaneous luminosity (rate of collisions) by a factor of five beyond the original design value and the integratedluminosity (total collisions created) by a factor ten. The LHC is already a highly complex and exquisitely opti-mised machine so this upgrade must be carefully conceived and will require about ten years to implement. Thenew configuration, known as High Luminosity LHC (HL-LHC), relies on a number of key innovations that pushaccelerator technology beyond its present limits. Among these are cutting-edge 11-12 tesla superconducting mag-nets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology andphysical processes for beam collimation and 100 metre-long high-power superconducting links with negligibleenergy dissipation. The present document describes the technologies and components that will be used to realisethe project and is intended to serve as the basis for the detailed engineering design of HL-LHC.