Superconductivity and Cryogenics for Future High-Energy Accelerators

High-energy particle accelerators are used to create new forms of matter, probe its structure at very small scales, reproduce in the laboratory very high temperature conditions naturally present in astronomical or cosmological objects, and generate high-brilliance electromagnetic radiation. To accelerate, guide and focus beams of charged particles, they produce electrical and magnetic fields in RF cavities and electromagnets. Economically attaining higher fields is an essential condition for sustaining development of performance while containing increase in size, capital and operating costs. Superconductivity and cryogenics have therefore become and will remain enabling technologies for high-energy accelerators. After discussing the rationale for their use, we present several projects of future machines, under construction or under study, with emphasis on their specific requirements, constraints and adopted solutions.