Measurement and reduction of transverse emittance blow-up induced by space charge effects

The CERN PS, as part of the LHC injector chain, will have to keep a high intensity, high brilliance beam for 1.2 s at the injection energy. The transverse particle density will exceed, by a factor of three, the highest currently attained. Careful experimental studies have recently been carried out in the PS to investigate transverse emittance blow-up in such a severe space charge regime. In addition, a new controlled longitudinal blow-up technique has been developed to produce bunches with flat-topped density profiles and, accordingly, reduced peak current. The results achieved so far are presented and discussed