Figure 4
(a) Example of the emission flux spectra of the planar adjustable-phase undulators APU22 installed at EMA and MANACÁ at Sirius, with the third harmonic tuned at 9 keV. The first nine harmonics are shown for a given deflection parameter Ku, and three different beamline angular acceptance windows (v × h) illustrate its effect in peak energy width and flux. (b) Arbitrarily scaled energy value Eu for a given emission harmonic nu and its derivative with respect to phase, for a normalized undulator phase pu in a planar APU, according to (14). (c) Top: zoomed spectral flux plot of the example emission of (a), highlighting the broadening of the peak and its shift to lower energies for larger angular acceptances; bottom: `slitless' wave-propagation simulations showing the beam profile for perfectly monochromatic energies at and around the 9 keV resonance (black vertical dashed lines in the plot). |