Chih-Sheng Yang

Multipole Errors and Methods of Correction for TPS Lattice Magnets

Taiwan Photon Source (TPS) is a synchrotron radiation facility of medium energy, 3 GeV, and low emittance, under construction at National Synchrotron Radiation Research Center (NSRRC). The multipole errors of lattice magnets were rigorously examined and corrected so as to maintain the dynamic aperture of the electron beam in the storage ring. The lattice magnets were fully inspected at both the vendor and vendee sites. The multipole errors of the lattice magnets were tested and corrected. In particular, the sextupole magnets have the pole position adjusted to correct the multipole errors so as to conform to the specification. The yoke cutting is to correct the octupole error of the long-quadrupole magnets. The shimming of the magnetic center and the final examination of the magnets will be undertaken at NSRRC. In this paper, we report the methods of correcting the multipole errors, the magnetic center, and the performance of the TPS lattice magnets.

Design and Measurement of the Septum Magnet for the Taiwan Photon Source

The septum magnet bends the injection beam before the kicker magnet. The septum magnet is located near the storage ring in the Taiwan Photon Source (TPS). As the space from the magnet wall to the vacuum chamber of the ring is less than 3 mm, the leakage field of the septum magnet thus influences the stability of the electron beam in the storage ring. The main field and the leakage field of a septum of the direct-drive type are compared to one of the eddy-current type. The effects of the vacuum chamber and μ-metal are simulated with full-sine and half-sine current pulses with the OPERA-2D TR analysis module; measurement results are presented in this paper.

Integration Design and Installation of Girder Systems in the Injection Section of Taiwan Photon Source

The electron beam is injected from the end of the transport line into the injection section of the storage ring in Taiwan Photon Source (TPS). A girder system for the injection section has been designed to support AC/DC septum magnets, four kicker magnets (K1–K4), and vacuum chambers. The girder system includes three girders, a Rapson-slide mechanism, and stages for the septum/kicker magnets. To improve the reliability and the stability of the injected electron beam, the girder systems are designed and installed in the injection section of TPS, as described in this chapter. The positioning accuracy of installing three girders and the stages for septum/kicker magnet are, respectively, within 0.3 and 0.05 mm.

Constructing a Permanent Magnet Phase Shifter

A permanent-magnet (PM) phase shifter has been constructed for tandem elliptically polarizing undulators at the Taiwan photon source. To increase the magnetic field reproducibility and to allow installation in a limited space, a robust mechanical structure is desired. To decrease multipole errors and optimize the magnetic field, algorithms for magnet sorting were used and magnetic field shimming was done. The start-to-end construction of a PM phase shifter will be discussed and explained in detail.

Eight Tesla Superconducting Solenoid Magnet for the Magnetic Circular Dichroism Study

This study describes the design and testing of a superconducting solenoid magnet for soft X-ray magnetic circular dichroism (SXMCD) experiments at the National Synchrotron Radiation Research Center (NSRRC). The superconducting solenoid magnet provides an uniform field of up to 8 T in a bore of 55 mm in diameter and 0.5 m long. The superconducting solenoid is operated in a 4.5-K liquid helium bath for reducing the vibration level during the experiments. The magnet and its cryostat are optimized to prevent magnet quenching and lower liquid helium consumption. The magnet quench test and magnetic field measurements are also performed.