A Cold-Bore Vacuum System Design for POPAE

We have made a conceptual design of a cold-bore vacuum system for the Fermilab 1000 GeV × 1000 GeV colliding beam facility (POPAE). A double wall vacuum system is used between magnets and cryopumped molecular traps between the cold-bore and warm straight section regions. The beam-induced pressure rise phenomena has been taken into account as well as the liquid helium leak rate between the cold magnets and the vacuum bore. Since beam for POPAE will be injected at the desired energy, there are no heat loads from accelerated beam or eddy currents and the cold-bore system appears very attractive. This design is based on the best experimental evidence available today.