Characterization of undulator radiation from a high-field BL-16 multipole wiggler/undulator at the Photon Factory

Spectral characterization was made on undulator radiation from a 26-period high-field permanent magnet multipole wiggler/undulator at the 2.5-GeV Photon Factory storage ring. In an undulator mode of a weaker field version of the insertion device, the K parameter was tuned up to 5.8. Absolute spectral measurement showed source brightness of the first harmonic peak in the order of 1015 photons/s mrad2 100 mA 0.1% bandwidth over the full tunable range of the first peak from 40 to 400 eV. As for the higher harmonics, spectral profile, the peak brightness, and quasimonochromaticity were obtained in this transition region where the K parameter increased beyond unity.