# SXS

BACK

SXS beamline overview, showing control electronics, optical hutch and workstation.

# OVERVIEW

The SXS beamline is an experimental station dedicated to X-ray Absorption and Photoelectron Spectroscopy in the soft X-rays (1 to 5 keV) energy range. It focuses on to study the electronic, magnetic and geometric structures of materials with applications to atomic and molecular physics, analytical chemistry, environmental and geoscience. Other experimental techniques available include X-ray Magnetic Dichroism and Resonant Auger Spectroscopy.

The SXS beamline is operational for users since 1997 and a broad scientific community including material science, surface science, atomic physics and chemistry among others has used it. Due an increasing demand from the users, in 2009 this beamline had a new X-ray optics in order to provide photons in the energy range from 1000 eV up to 5000 eV.

SXS’ source is a 1.67T bending magnet. There is a nickel-coated and toroidal (1010 x 100 x 100 mm) water cooled mirror that focuses the photon beam at the sample position and it suppresses the harmonic contamination (> 6keV). The incident angle is 0.6 deg and the spot size is 0.6 x 1.2 mm (FWHM) at the sample position.

The monochromator is a double-crystal with 4 pairs of crystals: Si(111), InSb(111), YB66(400) and Beryl(1010). It works under high vacuum ($5 \times 10^{-8}$ mbar) and the first crystals are maintained below 30 Celsius by a water cooling system.

# EXPERIMENTAL TECHNIQUES

The following experimental techniques and setups are available to users in this beamline. To learn more about the techniques’ limitations and requirements (sample, environment, etc.) contact the beamline coordinator before submitting your proposal.

###### X-RAY ABSORPTION SPECTROSCOPY (XAS)

X-ray absorption spectroscopy (XAS) is a widely used technique for determining the local geometric and/or electronic structure of matter.

Setup: Conventional Total electron yield (TEY) and Fluorescence XAS

This setup is optimized for TEY and fluorescence XAS on “standard samples” in standard sample holders. The setup for these experiments, called BioXAS workstation has two electrometers (Io and sample signal), a silicon drift diode (SDD) fluorescence detector, chamber with a differential pumping and a room temperature sample stage (xyzθ). In order to use this setup, samples/environments must fit within our room temperature sample stage.

Recent publications using this setup:

Abdala DB et al., Residence time and pH effects on the bonding configuration of orthophosphate surface complexes at the goethite/water interface as examined by Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, Journal of Colloid and Interface Science 442 (2015) 15–21;

Andrini L et al., Extended and local structural description of a kaolinitic clay, itsfired ceramics and intermediates: An XRD and XANES analysis, Applied Clay Science 124–125 (2016) 39–45;

Dalfovo MC et al., Real-Time Monitoring Distance Changes in Surfactant-Coated Au Nanoparticle Films upon Volatile Organic Compounds (VOCs), J. Phys. Chem. C (2015), 119, 5098−5106;

Yasser AA et al., Photostability of gold nanoparticles with different shapes: the role of Ag clusters, Nanoscale, 2015, 7, 11273.

###### X-RAY PHOTOELECTRON SPECTROSCOPY (XPS)

Setup: Conventional XPS

This setup is intended for XPS on “standard samples” in standard sample holders. The setup for these experiments, called XPS workstation has two electrometers (Io and sample signal), a hemispherical electron analyzer (Phoibos 150), ultra-high vacuum chamber with base pressure about 5×10-10 mbar and a room temperature motorized sample stage (xyzθ). In order to use this setup, samples/environments must fit within our room temperature sample holder inside a high vacuum pre-chamber. The pre-chamber environment allow submitting the samples to different gas atmospheres, while heating up to 900 °C and, after the treatment, the sample holder is inserted within the analysis chamber, using a load lock system.

Recent publications using this setup:

Garcia-Basabe Y et al., The effect of thermal annealing on the charge transfer dynamics of a donor–acceptor copolymer and fullerene: F8T2 and F8T2:PCBM, Phys.Chem.Chem.Phys., 2015,17, 11244;

Larrude DG et al., Electronic structure and ultrafast charge transfer dynamics of phosphorous doped graphene layers on a copper substrate: a combined spectroscopic study, RSC Adv.,2015,5, 74189;

Martins HP et al., X-ray absorption study of the Fe and Mo valence states in Sr2FeMoO6, Journal of Alloys and Compounds 640 (2015) 511–516;

Silva DO et al., Straightforward synthesis of bimetallic Co/Pt nanoparticles in ionic liquid: atomic rearrangement driven by reduction–sulfidation processes and Fischer–Tropsch catalysis, Nanoscale, 2014, 6, 9085.

# LAYOUT & OPTICAL ELEMENTS

ElementTypePosition [m]Description
SOURCEBending Magnet0.00Bending Magnet D04 exit A (4°), 1.67 T
MirrorToroidal Horizontal and Vertical Focusing Mirror7.00Ni coated, RT = 668m, RS = 73mm, $\theta$=10 mrad
MonoDouble Crystal Monochromator11.75Water-cooled InSb(111), Si(111), YB$_{66}$ (400) and Beryl(10-10)

# PARAMETERS

ParameterValueCondition
Energy range [keV]1-5Si(111)
Energy resolution [$\Delta$E/E]$10^{-4}$Si(111)
Beam size at sample [$\rm mm^{2}$, FWHM]0.6 x 1.2at 3 keV
Beam divergence at sample [$\rm mrad^{2}$, FWHM]0.2 x 4at 3 keV
Flux density at sample [ph/s/$\rm mm^{2}$]$4\times10^{11}$at 3 keV

# INSTRUMENTATION

InstrumentTypeModelSpecificationsManufacturer
Total electron yield detectorElectrometer651420 pA – 2 mA rangeKeithley
Fluorescence DetectorSilicon drift diodeSuperFast SDDArea: 25 $\rm mm^2$; Energy resolution: 125–155 eVAmptek
Photoelectron analyzerHemisphericalPhoibos 150MCD with 9 channels; 3500 eV kinetic energySpecs
FurnaceHalogen lamps/ high vacuum-Max Temp.: 900°CLNLS in-house development
SputteringArgonIG2 ion source0.5-2kV; 2.5mm beam diameter at 25mmRBD
Residual gas analyzerMass spectrometerRGA2001-200 amu; quadrupoleSRS
Sample charge neutralizerElectron flood gunFG15/400-500 eV; 0-5 mASpecs
Sample Cells Liquid-Ultralene window; 4 x 113 $\mu \rm L$LNLS in-house development

# CONTROL AND DATA ACQUISITION

All beamline controls are done through EPICS (Experimental Physics and Industrial Control System), running on a PXI from National Instruments. The data acquisition is done using a Red Hat workstation with the Py4Syn, developed at LNLS by SOL group. CSS (Control System Studio) is used as a graphical interface to display and control the beamline devices.

# HOW TO CITE THIS FACILITY

Users are required to acknowledge the use of LNLS facilities in any publications and to inform the Laboratory about any publications, thesis and other published materials. Users must also cooperate by supplying this information upon request.

Support text for acknowledgements:

This research used resources of the Brazilian Synchrotron Light Laboratory (LNLS), an open national facility operated by the Brazilian Centre for Research in Energy and Materials (CNPEM) for the Brazilian Ministry for Science, Technology, Innovations and Communications (MCTIC). The _ _ _ beamline staff is acknowledged for the assistance during the experiments.

Additionally, in publications related to this facility, please cite the following publication.

ABBATE, F. C. VICENTIN, V. COMPAGNON-CAILHOL, M. C. ROCHA AND H. TOLENTINO, The soft X-ray spectroscopy beamline at the LNLS: technical description and commissioning results, J. Synchrotron Rad., 6, 964 (1999). doi:10.1107/S0909049599008122.

The soft X-ray spectroscopy beamline installed at a bending-magnet source in the LNLS is presented. A technical description of the main elements is given and some selected commissioning results are shown. The beamline optics was designed to cover the soft X-ray energy range from 790 up to 4000 eV. The bending-magnet source has a critical energy of 2.08 keV and delivers ~10^{12} photons.s^{-1}.mradH^{-1} (0.1% bandwidth)^{-1}(100 mA)^{-1}. The focusing element is a gold-coated toroidal mirror operating at an angle of incidence of 1°. The double-crystal monochromator has three pairs of crystals which can be selected by a lateral translation. The UHV experimental station is equipped with an ion gun, an electron gun, a LEED optics and an electron analyzer. The beamline is intended for X-ray absorption, photoemission, reflectivity and dichroism experiments. The beamline has been installed, commissioned, and is now open to the external users community.

TOLENTINO, V. COMPAGNON-CAILHOL, F. C. VICENTIN AND M. ABBATE,The LNLS soft X-ray spectroscopy beamline, J. Synchrotron Rad., 5, 539 (1998). doi:10.1107/S0909049597016087.

The soft X-ray spectroscopy beamline installed at a bending-magnet source at the LNLS is described. The optics are designed to cover energies from 800 to 4000 eV with good efficiency. The focusing element is a gold-coated toroidal mirror with an angle of incidence of 17 mrad. The UHV double-crystal monochromator has three pairs of crystals, Si (111), InSb (111) and beryl (10-10), that can be selected by a sliding movement. The UHV workstation is equipped with an ion gun, an electron gun, an electron analyser, LEED optics, an open channeltron and a photodiode array. This beamline is intended for photoemission, photoabsorption, reflectivity and dichroism experiments.

# PUBLICATIONS

Scientific publications produced with data obtained at the facilities of this beamline, and published in journals indexed by the Web of Science, are listed below.

Attention Users: Given the importance of the previous scientific results to the overall proposal evaluation process, users are strongly advised to check and update their publication record both at the SAU Online website and at the For the library, updates can be made by sending the full bibliographic data to the CNPEM library (biblioteca@cnpem.br). Publications are included in the database after being checked by the CNPEM librarians and the beamline coordinators.

SGM   SXS

Monfredini, T.; Quitán- Lara, H. M.; Fantuzzi, F.; Wolff, W.; Mendoza, E.; Lago, A. F.; Sales, D. A.; Pastoriza, M. G.; Boechat-Roberty, H. M.. Destruction and multiple ionization of PAHs by X-rays in circumnuclear regions of AGNs, Monthly Notices of the Royal Astronomical Society, v. 488, n. 1, p. 451-469, 2019. DOI: 10.1093/mnras/stz1021

SXS

Gonzalez, J. C. ; Simões, G.; Bernini, R. B.; Coutinho, L. H.; Stedile, F. C.; Nunez, C. V.; Vicentin, F. C.; Souza, G. G. B. de. Elemental Concentration and Sulfur Chemical Speciation in the Amazonian Plant Andira surinamensis Using Synchrotron Radiation Techniques (SR-XRF, XANES), RBS and WD-XRF, Journal of the Brazilian Chemical Society, v. 30, n. 9, p. 1887-1896, 2019. DOI: 10.21577/0103-5053.20190098

SXS

Borges, B. G. A. L.; Roman, L. S.; Rocco, M. L. M.. Femtosecond and Attosecond Electron Transfer Dynamics of Semiconductors Probed by the Core-Hole Clock Spectroscopy, Topics in Catalysis, v. 62, n. 12-16, p. 1004-1010, 2019. DOI: 10.1007/s11244-019-01189-8

SXS   TGM   XPD   XRF

Teixeira, V. C.; Silva, A. J. S. da ; Manali, I. F. ; Gallo, T. M.; Galante, D.; Ferreira, N. S.; Andrade, A. B.; Rezende, M. V. dos S.. Li-self doping effect on the LiAl5O8 luminescent properties, Optical Materials, v. 94, p. 160-165, 2019. DOI: 10.1016/j.optmat.2019.05.029

SXS

García- Basabe, Y.; Peixoto, G. F. ; Grasseschi, D.; Romani, E. C.; Vicentin, F. C.; Villegas, C. E. P.; Rocha, A. R.; Larrude, D. G.. Phase transition and electronic structure investigation of MoS2-reduced graphene oxide nanocomposite decorated with Au nanoparticles, Nanotechnology, v. 30, n. 47, p. 475707, 2019. DOI: 10.1088/1361-6528/ab3c91

SXS

Guedes, E. B.; Abud, F.; Martins, H. P.; Abbate, M.; Jardim, R. de F.; Mossanek, R. J. O.. Role of Ti-Ru interaction in SrTi0.5Ru0.5O3: Physical properties, x-ray spectroscopy, and cluster model calculations, Physical Review B, v. 100, n. 7, p. 075132, 2019. DOI: 10.1103/PhysRevB.100.075132

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