Spectral characterization of undulator radiation in the soft x-ray region

Absolute spectral measurement of undulator radiation from the Photon Factory undulator was performed in the soft x-ray region between 0.2 and 0.9 keV for various values of the field parameter K from 0.72 to 1.66 and the angular parameter γθ from 0 to 0.97. Dependence of the peak brightness and full fractional bandwidth of the first harmonic of undulator radiation on the parameters K and γθ was obtained. The analyses show that the brightness and the bandwidth are greatly dependent on the beam parameters and the observing condition.