Crosstalk Issues of Vicinity Magnets Studied With a Novel Rotating-Coil System

Taiwan Photon Source (TPS) is a low-emittance synchrotron radiation factory. The lattice magnets are located compactly within the limited space in the storage ring. The mutual proximity of the magnets induces field crosstalk and influences the dynamic aperture of the electron beam. The field becomes distorted, induced by the crosstalk within not only the iron yoke but also the edges of the magnets. Precise measurements with rotating-coil systems were conducted to characterize the integral field quality of the magnets; a new method to detect the center of magnets is presented. Simulation with TOSCA software was undertaken for comparison with these experimental results. We report the field distortions induced by crosstalk on the basis of our measurements and simulations. A misalignment effect between the quadrupole and sextupole magnets is discussed.