• F.-Y. Lin, C.-H. Chang, H.-H. Chen, J.C. Huang, M.-H. Huang, C.-S. Hwang, J.C. Jan, C.Y. Kuo, C.-S. Yang
  NSRRC, Hsinchu

Taiwan Photon Source (TPS) is a new third generation synchrotron storage ring with energy 3 GeV, which consists of 24 double-bend cells and its circumference is 518.4 m. Various accelerator lattice magnets which consist of 48 bending magnets, 240 quadrupoles and 168 multifunction sextupole magnets. All magnets pole profiles, edge shim and magnet end chamfer were designed in TOSCA and RADIA magnetic computation code. In order to verify the magnetic field quality of computation code, prototype magnets have been manufactured in this year. Two measurement systems, hall probe and rotating coils, were used for magnetic field mapping. This paper presents magnetic field mapping results of prototype magnets and compared with original magnetic circuit designs.

• J.C. Huang, C.-H. Chang, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin, C.-S. Yang
  NSRRC, Hsinchu

Pulsed magnet system of Taiwan Photon source(TPS) requires a very low stray field to avoid parasitic magnetic field into the stored beam. The stray field from storage ring(SR) injection septum is required to be less than 0.2 Gauss. The most common method to protect parasitic magnetic field is to use high permeability and conductivity material, such as a Mu-metal. A 1.2 ms half-sine wave pulse of up to 8280A current peak are supply to a septum and would result in eddy current loss in magnet and conductor current diffusion during the rapid charging on magnet. Moreover, competition between eddy current loss and magnetic permeability would lead to a complex phenomena inside the mumetal shielding cabinet and shielding performance. In this study, the magnetic shielding performance of a shielding cabinet was examined in different shielding cabinet geometry and thickness. The results were calculated in Opera software and show that there is a significant suppression of SR septum stray field when round shielding cabinet is in use.

• C. H. Chang, C.-H. Chang, H.-H. Chen, J.C. Huang, M.-H. Huang, C.-S. Hwang, F.-Y. Lin, C.M. Wu
  NSRRC, Hsinchu

An elliptically polarized undulator of length 3.5 m and period length 48 mm (EPU48) is designed to fulfil experiments on spin-polarized PES and inelastic scattering at the Taiwan Photon Source (TPS). EPU48 would be used to produce variously polarized light in the soft X-ray spectral domain 0.4-1.5 keV. To achieve efficient mechanical performance and a high quality of photon source, a new manufacturing method by casting is adopted to fabricate a key component of the carriage of the undulator at National Synchrotron Radiation Research Center (NSRRC). We expect this approach to bestow advantages of decreased assembly error, increased rigidity and highly precise properties. Here we describe details of the design of the magnetic circuit and the mechanical design of the EPU48 based on this new concept of engineering construction.