Multiple quadrupole magnetic center alignment on the glrder

Taiwan Photon Source (TPS) project has been proposed 3 years ago to create a 3GeV synchrotron light source. The designated ultra-low emittance of this new fight source requires high precision positioning of storage ring magnets. Among all the magnets, the alignment of quadrupole magnets is of most importance since it directly affects the closed orbit of electron beams. Conventional on-site alignment of quadrupole magnets was mainly relying on the theodolite performance. The cumulated errors could be in the order of 0.1mm. In this report, a new alignment scheme is proposed to enhance the on-site alignment of quadrupole magnets for TPS project. To achieve the high precision requirements, a device possessing the advantages of both Vibrating Wire Method (VWM) and Position Sensing Detector (PSD) is proposed. The development of this alignment device is anticipated to provide a better mechanism to properly align the quadrupole magnetic centres on girder with less than 20 mu m positioning errors.