3-DIMENSIONAL ION BEAM-PROFILE MONITOR FOR STORAGE-RINGS

We have developed a non-destructive three-dimensional beam-profile mon itor for storage rings. It allows the measurement of the complete prof ile of stored ion beams by simultaneously detecting electrons and ions created through ionisation of the residual gas. The horizontal coordi nate of each point in the profile is determined by detecting the ionis ed electrons, guided in a strong magnetic field, on a two-dimensional position sensitive detector. The magnetic field assures precision in t he determination of the absolute horizontal position of the ion beam a nd prevents the detection of background electrons originating outside the monitor's active volume. Simultaneously, the vertical coordinate o f the beam distribution is obtained by measuring the time difference b etween the detection of the electrons and the recoil ions in coinciden ce. The time of flight spectrum shows the different components of the residual gas and allows an intrinsic calibration of the physical param eters. We present results of a test: performed with an 8 MeV/u D+ beam at the storage ring CRYRING in Stockholm.