The vacuum upgrade of the CERN PS and PS booster

In order to reach the required vacuum improvement, besides a general cleaning action, adding sublimation pumps. and cryo pumps to the existing ion pumps was considered. There exists a CERN design of a Ti sublimation cartridge depositing Ti on the inside of a /spl phi/ 200 mm pump body along a length of some 150 mm. Connected with a proper conductance that gives a pumping speed around 600 l/s for air mixture at the beam tube. That would so roughly quadruple the pumping speed there. For the PS that would not be entirely sufficient, for the PSB a factor of more than 2 would still be missing. The choice of cryo pumping to improve pressure in high outgassing areas was not retained, but improving the vacuum quality of the beam tubes and specially of the necessary equipment in tanks was considered to be a more economic approach, certainly point of view of later exploitation cost.