Proposal of a Sorting Experiment at the Cern Sps

We propose to study the effectiveness of the sorting strategies on the CERN SPS using eight strong extraction sextupoles independently powered to simulate random errors. In order to find the best sequence of the sextupolar perturbations, some dynamical quantities computed through the perturbative tools of normal forms are used as quality factors. They provide a fast estimate of the beam stability wellcorrelated with the results of the element-by-element tracking simulations. The most effective quality factor is retained and minimized by an appropriate permutation of the position of the sextupoles along the SPS azimuth. The effectiveness of the ordering procedures is verified for extensive long term six-dimensional tracking. Situations are presented where the beneficial effect of the sorting is expected to be large and well measurable in realistic conditions of operations.