High performance flexible cryogenic helium transfer lines

Abstract

CERN has installed and is operating in its Intersecting Storage Rings a superconducting high-luminosity insertion, the main elements of which are eight superconducting quadrupole magnets, housed in liquid helium bath cryostats. The design and construction of the transfer lines are discussed with photos. The site erection is described and operational experience presented with typical pumping curve of transfer line insulation space charted. Insulation vacuum and thermal performance are shown with the two-phase flow in transfer line diagramed. The economics of the flexible lines are itemized.