# XRF

BACK

Sample mounting on the x-ray microprobe setup.

# OVERVIEW

The XRF beamline is an experimental station dedicated to X-ray Fluorescence Microscopy (XRFM), X-ray Fluorescence Tomography (XFCT) and Total Reflection X-ray Fluorescence (TXRF) analysis in the hard X-rays energy range (5 to 20 keV). The beamline’s focus is on the determination and mapping of trace chemical elements in samples with applications in the fields of analytical chemistry, biomedicine, environmental geochemistry and materials science.

XRF’s source is a 1.67T bending magnet. The monochromator vacuum chamber can be laterally displaced, so that the whole synchrotron spectra can also be used to excite the samples. The experimental facilities include one station consisting of a high vacuum chamber in which grazing incidence x-ray fluorescence experiments can be carried out. The chamber is equipped with remote-controlled XY$\rm \theta$y sample stages and a HPGe solid state detector, optimised for the detection of light element. The whole setup is mounted in the motorised lift table, which allows vertical positioning of the instruments on the plane where the incoming beam is mostly linearly polarized.

Applications include 2D XRF mapping and speciation of trace elements at 20 microns resolution, 3D information of elements in volumetric samples, analysis of very small masses deposited on flat substrate, trace impurities on surfaces of flat samples, chemical depth profiling surface analysis (from sub nm to mm range).

# 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 Fluorescence (XRF) Analysis

X-ray Fluorescence (XRF) is a well-established bulk analytical method for qualitative as well as quantitative determination of several elements in a sample, independent of their chemical form. Depending on the detection system configuration, can be classified as Energy Dispersive (EDXRF) or Wavelength Dispersive (WDXRF) systems.

Setup: X-ray Fluorescence Microscopy (XRFM)

This setup allows performing experiments with an X-ray microbeam. The microfocusing optics consists of a pair of bendable mirrors arranged in the so called Kirkpatrick-Baez configuration (KB). The X-ray microbeam is around 12 microns (vertical) by 22 microns (horizontal) in size. Fully remote-controlled XYZz sample stages can operate in air or under a nitrogen gas environment. The $\rm \mu$-XRF setup also includes an optical microscope and a Silicon Drift Detector (SSD).

Other setups include:

• Setup: Grazing Incidence X-ray Fluorescence Analysis (GI-XRF)
• Setup: X-ray Fluorescence Tomography (XFCT)
• Setup: Total Reflection X-ray Fluorescence (TXRF)

# LAYOUT & OPTICAL ELEMENTS

ElementTypePosition [m]Description
SOURCEBending Magnet0.0Bending Magnet D09 exit B (15°), 1.67 T , 0.92 mm x 0.57 mm
MonoDouble Crystal Monochromator11.2Si(111), Si(220), channel-cut type
M1Elliptical Vertical Micro- focusing Mirror14.9Rh coated, RT=334m (center), $\theta$=4 mrad
M2Elliptical Horizontal Microfocusing Mirror15.3Rh coated, RT=334m (center), $\theta$=4 mrad Rh coated, RT = 176m (center), $\theta$=4 mrad

# PARAMETERS

ParameterValueCondition
Energy range [keV]5-20Si(111) / Si(220)
Energy resolution [$\Delta$E/E]$10^{-4}$Si(111)
Beam size at sample [$\mu \rm m^{2}$, FWHM]22 x 12at 10 keV
Beam divergence at sample [$\rm mrad^{2}$, FWHM]10 x 1at 10 keV
Flux density at sample [ph/s/$\rm mm^{2}$/100 mA]$2 \times 10^{8}$at 10 keV
Flux at focal spot [ph/s/100mA]$2 \times 10^{12}$White beam

# INSTRUMENTATION

InstrumentTypeModelSpecificationsManufacturer
DetectorSilicon driftAXAS-A$30 \rm mm^{2}$ SDD, FWHM $\leq$ 139eV at 5.9keVKETEK GmbH
DetectorSilicon driftAXAS-A$7 \rm mm^{2}$ SDD, FWHM $\leq$ 139eV at 5.9keVKETEK GmbH
DetectorHPGeGUL0035$30 \rm mm^{2}$ Ultra-LGe, FWHM = 140 eV at 5.9keVCanberra
CryostatCryostream Cooler700 SeriesMinimum of 173K, with a gas stability of 0.1KOxford

# 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) are used as a graphical interface to display and control the beamline devices. Point-to-point or continuous scanning (“on-the-fly”) modes of operation can be used for data acquisition in 2D/3D experiments.

# 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.

PÉREZ, C. A., RADTKE, M., SÁNCHEZ, H. J., TOLENTINO, H., NEUENSCHWANDER, R. T., BARG, W., RUBIO, M., BUENO, M. I. S., RAIMUNDO I. M. & ROHWEDDER, J. J. R., Synchrotron Radiation X-Ray Fluorescence at the LNLS: Beamline Instrumentation and Experiments, X-Ray Spectrometry 28, 320–326 (1999). doi: 10.1002/(SICI)1097-4539(199909/10)28:53.0.CO;2-1

The x-ray fluorescence beamline of the Laboratorio Nacional de Luz S´ıncrotron (LNLS) is described. The main optical component of the beamline is a silicon (111) channel-cut monochromator, which can tune energies between 3 and 14 keV. A general description of two experimental stations is given. Beam characterization was done by measuring experimental parameters such as vertical profile and monochromatic flux. These results show that the photon flux at 8 keV in an area of 20 mm2 is 4.2 × 109 photons s−1. The possibility of achieving fine tuning of energies (high resolution) was confirmed. This paper presents some original results derived from the commissioning of the beamline, such as a comparison of detection limits in different experimental conditions, and a novel mechanical system to align capillaries together with a semi-automatic adjustment procedure. So far, there have been several proposals to perform a variety of experiments at this beamline, covering different fields, such as physics, chemistry, geology and biology.

# 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.

XRF

Khan, L. U.; Silva, G. H. da; Medeiros, A. M. Z.; Khan, Z. U. ; Gidlund, G. A. ; Brito, H. F.; Moscoso- Londoño, O.; Muraca, D.; Knobel, M.; Pérez, C. A.; Martinez, D. S. T.. Fe3O4@SiO2 Nanoparticles Concurrently Coated with Chitosan and GdOF:Ce3+,Tb3+ Luminophore for Bioimaging: Toxicity Evaluation in the Zebrafish Model, ACS Applied Nano Materials, v. 2, n. 6, p. 3414-3425, 2019. DOI: 10.1021/acsanm.9b00339

XRF

Freitas, D. S.; Rodak, B. W.; Carneiro, M. A C.; Guilherme, L. R. G.. How does Ni fertilization affect a responsive soybean genotype? A dose study, Plant and Soil, v. 441, n. 1-2, p. 567-586, 2019. DOI: 10.1007/s11104-019-04146-2

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

XRF

Cardoso, M. ; Barbosa, R. de F.; Torrente-Vilara, G. ; Guanaz, G.; Jesus, E. F. O. de; Mársico, E. T.; Ribeiro, R. O. R.; Gusmão, F.. Multielemental composition and consumption risk characterization of three commercial marine fish species, Environmental Pollution, v. 25, p. 1026-1034, 2019. DOI: 10.1016/j.envpol.2019.06.039

XRF

Rasera, J. R. S; Sant'Anna Neto, A. ; Monteiro, R. T. R.; Van Gestel, C. A. M.; Carvalho, H. W. P.. Toxicity, bioaccumulation and biotransformation of Cu oxide nanoparticles in Daphnia magna, Environmental Science-Nano, v. 6, n. 9, p. 2897-2906, 2019. DOI: 10.1039/c9en00280d

XRF

Dias, C. S. B.; Garcia, F.; Mazali, I. O.; Cardoso, M. B.; Silva, J. M. S.. Direct route for preparing multi-oxide inorganic nanocomposites of nanoparticles-decorated nanotubes, Journal of Alloys and Compounds, v. 774, p. 1133-1139, 2019. DOI: 10.1016/j.jallcom.2018.09.358

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