Observation of ion trapping at Adone

Ion trapping is a well known phenomenon in electron storage rings. The details of the interaction between the stored electron beam and the ions created in the residual gas are particularly interesting for all machines where ion induced frequency spread and beam blow-up can be of concern. Several theoretical models have been worked out but detailed experimental results are lacking. An extensive set of measurements is in progress at Adone to establish the dependence of ion trapping on various machine parameters. The experimental set-up and the first results are described. (Auth.)