Test of the Sorting Methods at the CERN-SPS

An external study of the effectiveness of the sorting strategies on the CERN Super-Proton-Synchrotron is proposed. The eight strong extraction sextupoles used for diffusion experiments can be independently powered to simulate random errors. Numerical computations show that a significant spread in the dynamic aperture can be obtained. A sorting strategy based on analytical quality factors allows a considerable improvement on the beam stability. A complete analysis of the possible permutations shows that the good configurations are rather abundant. The effectiveness of the ordering procedure is verified for long-term six-dimensional motion and different working points. Situations are presented where the beneficial effect of the sorting is expected to be large and well measurable in realistic conditions of operation.