RESUMEN
Resonant inelastic X-ray scattering in the XUV-regime has been implemented at BESSY II, pushing for a few-meV bandwidth in inelastic X-ray scattering at transition metal M-edges, rare earth N-edges and the K-edges of light elements up to carbon with full polarization control. The new dedicated low-energy beamline UE112-PGM1 has been designed to provide 1â µm vertical and 20â µm horizontal beam dimensions that serve together with sub-micrometre solid-state sample positioning as the source point for a high-resolution plane grating spectrometer and a high-transmission Rowland spectrometer for rapid overview spectra. The design and commissioning results of the beamline and high-resolution spectrometer are presented. Helium autoionization spectra demonstrate a resolving power of the beamline better than 10 000 at 64â eV with a 300â linesâ mm-1 grating while the measured resolving power of the spectrometer in the relevant energy range is 3000 to 6000.
RESUMEN
A new but yet well proven way of making elliptically polarized dipole radiation from the BESSYâ II storage ring applicable to the SX700-type collimated plane-grating monochromator PM3 is described. It is shown that due to the limited vertical acceptance of the grating a simple use of vertical apertures is not possible in this case. Rather, deflecting the beam upwards or downwards by rotating the vertically collimating toroidal mirror M1 around the light axis leads to excellent performance. The resulting detuning of the photon energy can be taken into account by a readjustment of the monochromator internal plane mirror M2. The energy resolution of the beamline is not affected by the non-zero `roll' of the collimating mirror.