Figure 1
Undulator spectra (APS upgrade, 2.6 cm-period) normalized to the FWHM of the first harmonic in each trace. Upper (lower) panel: after (before) reflections from the M1 and M2 mirrors. Solid (black) line: undulator tuned to 5 keV and mirrors coated with C. Dotted (red) line: undulator tuned to 6.5 keV and mirrors coated with Rh. Dashed (green) line: undulator tuned to 10 keV and mirrors coated with Rh. |