Stochastic cooling and storage tests with oxygen ions in LEAR

O⁸⁺ and O⁶⁺ ions were stored in the CERN Low-Energy Antiproton Ring (LEAR) during a machine experiment session. The aim was to obtain some hints on the lifetime of heavy ion beams in a good cooling ring vacuum and to test cooling and stacking of ions. Stochastic cooling was used to compensate the beam decay due to multiple scattering on the residual gas, which is the most important effect on lifetime. An equilibrium momentum spread of less than 5×10^-4 was measured, thus proving the efficiency of stochastic cooling for multiply charged ions. With the vacuum conditions of LEAR (2.6×10^-12 torr gauge reading with a residual gas of 90% H₂), measured beam lifetimes are 25 min for O⁶⁺ at 7.2 MeV/u and 600 min for O⁸⁺ at 11.5 MeV/u. These numbers set favorable limits for low-energy ion storage rings