EXPERIMENTAL STUDY ON THE 5TH ORDER NONLINEAR RESONANCE AT TAIWAN LIGHT SOURCE

The 5th order nonlinear resonance was studied at SRRC's electron storage ring, which has working tunes around ν x = 7.23 and νy = 4.17. This resonance is interesting due to the possible systematic errors from its 6-fold symmetry lattice design. In order to understand the dynamics of resonance and effects of betatron decoherence and linear coupling, experiments have been performed using the 2-BPM turn-by-turn method and phase space maps to study its phenomena. The experimental results are presented. 1 INTROCUCTION Nonlinear beam dynamics experiments have been performed at many accelerator facilities for various resonance phenomena at different resonance conditions [1,2,3,4]. The sextupoles, octupoles and higher order multipoles in the accelerator can produce the non-linear effects that perturb the beam orbit and give the phase space significantly different from that with linear lattice elements. When the betatron tune is near a resonanc