Sensitivity reduction against misalignment of quadrupole and sextupole magnets

A method of aligning quadrupole and sextupole magnets was proposed. The method treats the quadrupole and sextupole magnets between the bending magnets as a unit and aligns their magnetic center precisely before setting it on a design orbit. Alignment between each unit is done by the usual way which results in an error of 0.1 to 0.3 mm. The authors derived the equation for closed orbit distortion in the proposed alignment method and applied it to the SPring-8 storage ring. They found that the closed orbit distortion was reduced to less than 50%.<>