Dynamic vacuum in the beam tube of the SSCL collider-cold beam tube and liner options

in this paper model equations are derived for calculating the beam tube density of molecules desorbed by synchrotron radiation in the SSCL 20 TeV proton Collider and the supporting simulation experiments at synchrotron light sources. Cold 4.2 K beam tube and arbitrary temperature liner or distributed pump systems are considered. Physical effects included are; direct desorption, cryosorption, desorption of physisorbed molecules, the H₂ equilibrium isotherm, axial diffusion and distributed pumping. Convenient formulas are given for extracting the relevant physical variables from the simulation experiments and calculating the anticipated beam tube density in the Collider. A numerical example illustrating the important physical effects is presented