The low beta insertions in the SPS and their chromaticity correction

Two low beta insertions are foreseen for the p-anti p collider in the SPS. With the addition of some quadrupoles in the regular machine lattice several insertion configurations are possible, thus allowing a wide range of beta values at either one or both interaction points. This scheme requires a chromaticity correction by four independent families of sextupoles, whose strengths are calculated by minimizing the second order variations of the tunes with the momentum deviation. Experiments simulating the large betatron perturbations induced by the insertions have shown the feasibility of the proposed scheme which should provide a gain in luminosity factor greater than 35. (Auth.)