Study of CANDLE tunes dependence on fringing fields of quadrupoles

The main features of electron beams in third generation light sources are small emittance and long lifetime. Consequently, very accurate beam dynamics consideration is required that corresponds to real magnetic field distribution around the ring. The fringe fields are the unavoidable part of any real magnet design and sometimes may have essential influence on beam dynamics because they appear in all orders of particle motion, including the linear one. A simple approach to calculation of fringing field effects on beam dynamics in storage rings based on direct integration method using MATLAB ODE23 solver is presented in this paper. The numerical results of quadrupole magnet fringe field induced tune shift and chromaticity change in CANDLE (Design Report, Yerevan, Armenia, 2002) light source are given in comparison with the linear matrix calculations in rectangular magnetic field approximation.