Perturbation of relevant resonance for slow extraction efficiency increase

In a synchrotron, slow extraction of a circulating beam when influenced by a nonlinear perturbation was analysed both analytically and by computer simulation. It was found that beam loss on the septum may be reduced twice and more if the particle distribution in the cross section of the kicker magnet is deformed with decapole perturbation of a sextupole magnetic field used for resonance excitation. A similar effect is observed for gradient resonance extraction with octupole perturbation. Results of simulation for the ITEP PS slow extraction system are presented