Abstract
We developed SR compact superconducting magnets which are used for X ray lithography. If the vertical axis of the superconducting coil of SR magnet is out of the vertical line the horizontal field Bx will be appeared. The electron beam is kicked toward vertical direction by this field and this causes a large electron beam orbit distortion in the horizontal coordinate. From the beam optics, the gradient of the coil axis needs to be less than 1 mrad. We developed a magnetic field distribution measurement system of the horizontal magnetic field Bx(s) in the high bending magnetic field By0 which is 3.5T at the center of the SR (Synchrotron Radiation) magnet and measured the distribution of Bx(s) . Where, s is the beam direction. From the horizontal magnetic field Bx(s) and vertical dipole field By0(=3.5T), we can evaluate the gradient of bending field from the vertical direction. The average gradient along S direction was 0.55mrad. This value satisfies our requirement which is less than 1mrad.
