Integral dipole field calibration of the SRRC storage ring combined function bending magnets

Due to the presence of the fringe field on both magnet edges, the real trajectory traced out by the beam will deviate from expectation. The integral dipole strength seen by the beam will then have a discrepancy to design value. The beam tracing method is employed to correct the fringe field effect and to calibrate the integral dipole strength of the bending magnets by tuning magnet current. The final correction factor was achieved in the condition of simulated results met to design requirements. During machine commissioning, the measured betatron tunes were found different from modeling and a correction factor was applied to correct this tune difference. This factor is in well agreement with that predicted by the beam tracing method