| Popis: |
Since it was first made operational, in 1976, the vacuum system of the 400 GeV proton accelerator (SPS) has been gradually developed to produce lower pressures, in order to meet the requirements of proton-antiproton collider operation which began in 1981. The vacuum measurement equipment installed originally was designed to cope with pressure down to 10 −8 mbar. For collider operation this limit had to be lowered to below 10 −9 mbar. Studies of the cold cathode gauges and the sputter-ion pumps which are used to monitor the pressures in the SPS vacuum system showed that, by improving the read-out systems, the gauges could be used to measure pressures as low as 10 −10 mbar and useful pressure estimates, to about the same level, could also be made with the sputter-ion pumps, under certain conditions. When the SPS vacuum system was pumped for periods of several months it reached an average pressure in the mid 10 −10 mbar range. |
