Shaping of proton distribution for raising the space-charge of the CERN PS booster

The intensity of the PS booster is limited by space-charge defocusing forces which create a spread in the betatron tunes of up to ΔQ approximately equal to 0.5. Shaping of the transverse and longitudinal distributions was used for accommodating more particles in a given working area and enabled the Booster to accelerate 2 x 1013 protons per pulse, twice the design intensity. Modifying the RF potential well by an experimental second-harmonic cavity yields beam intensities well beyond the present performance. The corresponding PSB experiments and improvements are described and an outlook on future developments is given. (Auth.)