[en] The calculation technique of the vacuum parameters of the synchrotron constant-charge heavy ion accelerators is developed. Inelastic interaction cross sections of the residual gas medium atoms with the accelerated ions are given. Simple and practically convenient dependences are found permitting to determine the tolerable residual gas concentration as a beam parameter function for acceleration and storage modes and to select the ultrahigh vacuum evacuation devices. The table of the designed vacuum parameters of the largest home-made multi-charged ion synchrotrons is presented. It is concluded that the creation of efficient vacuum system supposes electrochemical polishing of the chamber surface and thermal outgassing in oilless vacuum at the temperature up to 800 deg C, chamber heating up to 150-200 deg C upon assembly, chamber internal surface processing in a glow discharge plasma in an argon-oxygen mixture medium and the use of ultra high vacuum evacuation devices with the ultimate residual pressure approximately 10^-10 Torr and evacuation rate approximately 500 l/s. Pumps with evacuation rate approximately 10⁴ l/s should be applied in the zone of built-in magnets of the beam monitoring system