No abstract

A method based on wave optics together with electron tracking is used to analyze synchrotron radiation from a segmented undulator in a double or multi mini‐β function lattice storage ring. Radiation brilliance and transverse coherence features are investigated, where the former is calculated with the Wigner distribution function and the latter is evaluated by integrating the photon flux and cross‐spectral density to exhibit the coherent flux and overall degree of coherence. To be specific, radiation properties for a single undulator in a typically single mini‐β function and a tandem undulator in a double mini‐βy lattice are compared in this work. As a result, both, brilliance and coherent flux can be enhanced by a second tandem undulator at the Taiwan Photon Source.

The resonant photon energy of an adjustable-phase undulator (APU) is varied with the relative motion of the magnet arrays along the longitudinal direction. There exists, however, a transverse field gradient (TFG) of order 100 T/m in an APU of small gap (∼10 mm). Whereas the TFG might affect the electron beam as it contributes to the dynamic field integral and the radiation integrals, the TFG might also degrade the performance of the synchrotron radiation due to the transverse position-dependent magnetic field. The effects of the TFG on the present Taiwan Photon Source (TPS) and future TPS-upgraded are analyzed to investigate the feasibility of an APU that operates in the soft x-ray region.