Speaker
Description
This lecture aims at giving non-expert engineers and scientists working in the domain of accelerators a general introduction to the main disciplines and technologies involved in the design and construction of accelerator cryostats for superconducting (SC) devices.
The main functions and requirements for cryostats for SC devices are presented, supported by examples from accelerators like LHC, HIE Isolde and XFEL. Engineering solutions adopted in cryostat design are also illustrated throughout the lecture. An overview of the operating temperatures and pressures for the SC devices is given, presenting the working points on the phase diagram of helium. Thermal heat loads and thermodynamic efficiency in heat extraction in large cryogenic state-of-the-art cryoplants is recalled.
Thermal heat exchange mechanisms in cryostats, in particular thermal radiation and solid conduction are covered, providing simplified calculation formulas for preliminary design.
Thermal shielding, multi-layer insulation (MLI) systems, supporting systems and heat interception in feedthroughs are illustrated. Vapor cooling in current leads and RF power couplers is mentioned. Some basic aspects of cryostat construction, precautions with pressure vessels and compliance with Pressure Equipment Directive (PED) are underlined. The relevant mechanical failure mechanisms in cryostat components are illustrated. Cryogenic safety in cryostats, and potential cryogenic pressure hazards and the sizing of the pressure safety devices concludes this lecture.