Journal of large-scale research facilities, 2, A54 (2016) http://dx.doi.org/10.17815/jlsrf-2-78 Published: 03.03.2016 The UE49 SGM RICXS beamline at BESSY II Helmholtz-Zentrum Berlin für Materialien und Energie * Instrument Scientists: - Dr. Annette Pietzsch, Helmholtz-Zentrum Berlin für Materialien und Energie, phone: +49 30 8062-12919, email: annette.pietzsch@helmholtz-berlin.de - Prof. Dr. Stefan Eisebitt, Technische Universität Berlin and Helmholtz-Zentrum Berlin für Materi- alien und Energie, Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie im Forschungs- verbund Berlin e.V., phone: +49 30 6392 1301, email: eisebitt@mbi-berlin.de Abstract: Beamline UE49-SGM is a dedicated high-�ux soft x-ray beamline, spanning the energy range of 95 eV to 1400 eV. Its micrometer focus makes it ideally suitable for investigation of small or inhomoge- neous samples both with spectroscopic methods and coherent scattering as well as imaging techniques with full polarization control. 1 Introduction The UE49SGM RICXS beamline is a dedicated high-�ux-density beamline, which accomodates two permanent experimental set-ups for x-ray scattering: the Resonant Inelastic X-ray Scattering (µ mRIXS) and the Coherent X-ray Scattering (CXS) end-stations. The µmRIXS experiment is designed for resonant X-ray Raman studies of solid samples under ultra-high vacuum conditions and in the temperature range from liquid He to room temperature. It is equipped with a confocal plane grating spectrometer, which allows optimizing the operation mode between high signal-transmission and high energy-resolution. The CXS set-up allows the use of coherent X-rays in scattering, imaging and spectroscopy applications. In particular, the transverse and longitudinal coherence length can be optimized for the particular experiment to maximize the coherent photon �ux on the sample. A large part of reciprocal space can be covered by a moveable 2048 x 2048 pixel soft X-ray CCD detector (moveable in situ by ±45° horizontally and vertically with adjustable pixel oversampling ratio). A 3D magnetic vector �eld of up to 1 T is available as sample environment. The characteristics of the RICXS beamline were designed to meet the high demands of the two techniques, which are high (coherent) photon �ux, a µm-size beam focus and full polarization control (linear and circular). It can be operated in the energy range 95 – 1400 eV, covering the resonant transitions of many relevant elements, such as silicon and phosphor L- *Cite article as: Helmholtz-Zentrum Berlin für Materialien und Energie. (2016). The UE49 SGM RICXS beamline at BESSY II. Journal of large-scale research facilities, 2, A54. http://dx.doi.org/10.17815/jlsrf-2-78 1 http://jlsrf.org/ http://dx.doi.org/10.17815/jlsrf-2-78 http://dx.doi.org/10.17815/jlsrf-2-78 https://creativecommons.org/licenses/by/4.0/ Journal of large-scale research facilities, 2, A54 (2016) http://dx.doi.org/10.17815/jlsrf-2-78 edges, lanthanide N4,5-edges, carbon, nitrogen and oxygen K-edges and transition metal L2,3-edges. The beamline is realized as a spherical grating monochromator (SGM) with a Kirkpatrick Baez refocusing stage. It is optimized for high transmission by minimizing the number of re�ections, with the liquid nitrogen cooled grating being the �rst optical element to directly accept the undulator radiation. The monochromator accommodates three laminar gratings: 180 l/mm (operation range: 95 – 270 eV, best energy resolving power E/∆E = 6500 at 95 eV), 410 l/mm (180 – 650 eV, E/∆E = 10000 at 210 eV), 900 l/mm (400 – 1400 eV, E/∆E = 12000 at 450 eV). Figure 1: Top-view of beamline UE49 SGM | RICXS. 2 Instrument application Typical applications for µ mRIXS are: • study of low-energy excitations in solids (study of magnetic, orbital, nuclear and charge degrees of freedom and their interplay) • study of the electronic structure of solids (the size of band-gaps and band-widths) • study of materials showing phase separation with µm-real-space resolution Typical applications for CXS are: • studies of nanomagnetic phenomena via x-ray magnetic circular or linear dichroism • x-ray holography, coherent di�raction imaging and ptychography • coherent resonant x-ray scattering in transmission and re�ection geometry 3 Source The insertion device is the elliptical undulator UE49 with the following parameters: 2 http://dx.doi.org/10.17815/jlsrf-2-78 https://creativecommons.org/licenses/by/4.0/ http://dx.doi.org/10.17815/jlsrf-2-78 Journal of large-scale research facilities, 2, A54 (2016) Type APPLE2 Location L108 (low beta section) Periode length 49 mm Periods/Pols 64 Minimal Energy at 1.7 GeV 91.2 eV Minimal Gap 16 mm Polarisation linear variable 0° ... +90° elliptical, circular Table 1: Parameters of insertion device UE49. 4 Optical Design To ensure maximum �ux, the optical beamline design consists of only three optical elements: a spherical VLS grating with a vertical de�ection angle of 175° and a Kirkpatrick Baez refocusing stage. Figure 2: Optical layout of beamline UE49 SGM | RIXCS. 5 Technical Data Location 10.1 Source UE49 Monochromator Spherical VLS grating monochromator Energyrange 90 - 1400 eV Energyresolution 4000 - 12000 Flux Up to 7·1014 photons / s / 0.1 A / 0.1 % BW Polarisation Full polarization control Focus size (hor. x vert.) 4 µ m x 1 µ m (hor. x vert.) Height Focus/�oor level 1100 mm Free photon beam available No Fixed end station Yes Table 2: Technical data of Beamline UE49 SGM | RIXCS. 3 http://dx.doi.org/10.17815/jlsrf-2-78 https://creativecommons.org/licenses/by/4.0/ Journal of large-scale research facilities, 2, A54 (2016) http://dx.doi.org/10.17815/jlsrf-2-78 References Helmholtz-Zentrum Berlin für Materialien und Energie. (2016a). CXS: Coherent X-ray Scat- tering at the UE49-SGM at BESSY II. Journal of large-scale research facilities, 2, A56. http://dx.doi.org/10.17815/jlsrf-2-81 Helmholtz-Zentrum Berlin für Materialien und Energie. (2016b). The µmRIXS spectrometer at BESSY II. Journal of large-scale research facilities, 2, A55. http://dx.doi.org/10.17815/jlsrf-2-80 Könnecke, R., Follath, R., Pontius, N., Schlappa, J., Eggenstein, F., Zeschke, T., . . . Föhlisch, A. (2013). The confocal plane grating spectrometer at BESSY II. Journal of Electron Spectroscopy and Related Phenomena, 188, 133 - 139. http://dx.doi.org/10.1016/j.elspec.2012.11.003 4 http://dx.doi.org/10.17815/jlsrf-2-78 http://dx.doi.org/10.17815/jlsrf-2-81 http://dx.doi.org/10.17815/jlsrf-2-80 http://dx.doi.org/10.1016/j.elspec.2012.11.003 https://creativecommons.org/licenses/by/4.0/ Introduction Instrument application Source Optical Design Technical Data