# OVERVIEW

BACK

The XPD beamline is an experimental station dedicated to Powder X-ray Diffraction analysis and operates from 6 to 12 keV. However, the energy is set at 8keV (for maximum flux) and it is only changed to perform anomalous scattering experiments or to eliminate the effect of fluorescence for samples containing specific elements, such as Fe, Cu and Co. The beamline focuses on the structural studies of crystalline and nanocrystalline materials and it is able to perform both high resolution and faster in-situ experiments under non-ambient conditions.

XPD’s source is a 1.67T bending magnet, with a Huber 4+2 circle diffractomete, working in Bragg-Brentano geometry (theta-2theta) providing high quality powder diffraction data. Powder X-ray diffraction techniques largely benefit from the high-brilliance of synchrotron light sources in terms of photon flux, angular resolution, higher resolution, energy tunability as well as in situ studies in combination with fast detectors.

XPD is a beamline for studying the structure of all forms of polycrystalline materials, especially in a powder form. It offers the acquisition of powder patterns in high resolution mode, allowing the investigation of strain, lattice defects, and micro-structure of materials at ambient and cryogenic temperatures. In addition, powder diffraction using a synchrotron radiation X-rays source and fast detectors has become an essential technique for studying the change in crystalline or nanosized materials as a function of time under a variety of experimental conditions such as, temperatures ans gas. XPD allows kinetic experiments using a furnace installed onto the diffractometer, which allows gases to interact with the samples to simulate various reaction conditions or environments. A Mythen 1k linear detector can be used for fast data acquisition during in situ experiments. The beamline energy can be changed to perform anomalous scattering experiments, in which the contrast between scattering factors of different elements can be conveniently tuned. Energy tunability also eliminates the effects of fluorescence.

# CONTACT & STAFF

Beamline Phone Number: +55 19 3512 1131
Beamline E-mail: xpd@lnls.br

Coordinator: Cristiane Barbieri Rodella
Number: +55 19 3512 1040
E-mail: cristiane.rodella@lnls.br

# 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.

###### AMBIENT MEASUREMENTS

Ambient measurements are conducted on samples which require the high resolution capability of the beamline. Here samples are measured under ambient temperatures and are exposed to the atmosphere during measurements. The setup gives accurate peak position and shape and reduces peak overlap of highly crystalline materials while reducing background signal. This set-up is normally required for quantitative analysis of samples, i. e. Structure determination of performing Rietveld Refinement to determine crystalline parameters, such as cell parameter and volume, crystal size, investigation of strain, lattice defects and micro-structure of materials. It is carried out at ambient conditions (room temperature) in Bragg-Brentano geometry or at cryogenic temperature with a cryostat. It is important to note that the cryostats work without sample spinning during the measurement. High resolution requires an analyzer crystal, a Ge (111) crystal, installed before the point detector (Cyberstar scintillation detector), which provides a step-size resolution of 0.002° in 2θ2θ. This analysis mode results in low photons flux and thus a lower intensity of the diffracted beam and consequently, longer data acquisition times (8-14 hours for each sample).

###### IN-SITU MEASUREMENTS

Canario Furnace

These measurements involve the use of a furnace with the additional capability of gas flow. With this setup various types of reactions can be simulated. The temperature range is dependent on the furnace used (please see types of furnaces available at the beamline). Various gas environments are allowed to simulate chemical reactions. Some restrictions are in place for safety as well as preventing damage to the furnaces. Thus, no corrosive gases are allowed. Further, restrictions apply to the use of hydrogen (5% max) and oxygen (20% max). We strongly urge you to contact the beamline staff prior to sending a beamtime proposal to certify that your experiment fits into our safety regulations. A mild vacuum may be applied to the furnace as well as humidity if required. A mass spectrometer is also available to analyze the chemical composition at the outlet of the furnace. The appropriate furnace will be selected by the beamline staff depending on the needs of the user.

The in-situ setup works for both fast measurements (lower resolution) using the Mythen 1K detector as well as the High resolution setup using the Cyberstar point detector. Please note the large time differences in collecting data between these two detectors. For further information about more complex setups, please contact the beamline staff.

###### CRYOSTAT

For low temperature measurements, a cryostat from Advanced research systems is available. The lowest temperature achievable is around 10 K. The measurement at low tempetature using cryostat can be carried out using fast detector Mythen or the Cyberstar point detector

###### SAMPLE PREPARATION

Sample holders from left to right: Furnace, cryostat, High-resolution

Depending on the type of experimental setup required samples may be prepared as either a powder or pellet. Powder samples are preferred however. Samples need to be ground down to the finest possible size to avoid sample related effects affecting the data. This applies to all data collections.

###### BEAMLINE ENERGY

XPD is normally fixed at 8 keV (λ=1.5498Å) which corresponds to the highest photon flux and is equivalent to Cu Kα wavelength used in conventional X-ray sources. However, the energy may be changed if anomalous diffraction experiment are required or if the sample is composed of Fe and/or Co. The energy is then set to 7 keV to avoid fluorescence. It is also possible to work at higher energies if it is important to increase the penetration depth of the X-rays into the sample, in the case of samples composed of high Z materials.

# LAYOUT & OPTICAL ELEMENTS

ElementTypePosition[m]Description
SRCBending Magnet0.0Bending Magnet D10 exit B (15°), 1.67 T,
FEFront-end--
S1White Beam Slits6.2LNLS Slits (Cu and Ta)
M1Cylindrical Vertical Collimating Mirror7.3Rh coated ULE, R = 1.7 to 21.7 km, $\theta$ = 4.5 mrad
DCMDouble Crystal Monochromator8.6Water cooled Si (111)
S2Monochromatic Beam Slits20.0LNLS Slits (Cu and Ta)
ESExperimental Station21.94+2 circles Huber diffractometer

# PARAMETERS

ParameterValueCondition
Critical Energy [keV]2.08-
Energy range [keV][Å]4.5-15 (2.76-0.83)Si (111)
Energy resolution [$\Delta$E/E]$2.5 \times 10^{-4}$Si (111)
Beam size at sample [$\rm mm^{2}$, FWHM]3 x 2at 8 keV
Beam divergence at sample [$\rm mrad^{2}$, FWHM]1 x 0.1at 8 keV
Flux density at sample [ph/s/$\rm mm^{2}$]$2.5 \times 10^{10}$at 8 keV

# INSTRUMENTATION

InstrumentTypeModelSpecificationsManufacturer
DetectorLinearMythen 1k$50 \mu \rm m$ pixel, 1280 pixel, 2kHz frame rateDectris
DetectorPoint DetectorCyberstar X1000$\phi$ = 30 mm, Tl-doped NaI (NaI(Tl)), $10^6\, \rm counts.s^{-1}$FMB Oxford
DetectorCCD CameraX-ray eyeA-ray sensitive CCDPhotonic Science
FurnaceIn-situ High Temperature Diffraction chamberAraraMax Temp.: 1000°C, Temp Rate: 10K/s, window port 210°LNLS in-house development
FurnaceIn-situ High Temperature Diffraction chamberCanarioMax Temp.: 1000°C, Temp Rate: 10K/s, window port 210°LNLS in-house development
FurnaceIn-situ High Temperature Diffraction chamberXRK900Max Temp.: 900°C, Temp Rate: 20K/sAnton Paar
Diffractometer4+2 circles5020$2 \theta$ max=150°; $\theta$ max=90°Huber
Eurellian Cradle2 circles513360° $\Phi$; $\chi$ max=150°, min=-45°Huber
CryostatsHe Closed Cycle Diffraction CryostatDE-202Closed Cycle Cryo-cooler, Temperature range: <10 K – 350K, Window Ports: 5 - 90° ApartARS Cryo
Analyzer CrystalMonochromatic CrystalGe(111)$2 \theta$ step: 0.0025°LNLS in-house development
Analyzer CrystalMonochromatic CrystalSi(111)$2 \theta$ step: 0.0025°LNLS in-house development
Analyzer CrystalMonochromatic CrystalHOPG(002)$2\theta$ step: 0.05°LNLS in-house development
Gas detectorMass SpectrometerQMA 100-Pfeiffer Vacuum
Gas detectorMass SpectrometerQMA 200-Pfeiffer Vacuum

# CONTROL AND DATA ACQUISITION

The beamline is controlled using EPICS (Experimental Physics and Industrial Control System) that is running on a PXI from National Instruments. All data acquisition and diffractometer movements are done using fourc mode on SPEC (software for instrumentation control and data acquisition in X-ray diffraction experiments from Certified Science Software).  For some graphical interfaces and beamline devices can be controlled using CSS (Control System Studio).

# APPLYING FOR BEAMTIME

Submission calls are usually announced twice per year, one for each semester. All the academic research proposals must be submitted electronically through the  Learn more about how to submit a proposal .

XPD beamline offers varied instrumentation setups to allow structural studies of materials. It is important when submitting a proposal to specify the required equipment and setup needed to carry out your experiments. Please see the information below to help you specify the beamline setup and accessories. However, it is important to contact the beamline staff before sending a proposal, especially if you are a new user or/and want to carry out a new experiment.

Beamtime: Working under ambient conditions, one XRD pattern will take from 6 to 14 hours in high resolution mode. This depends on the angular step and 2theta range of the experiment. It is important to consider that NIST standards are measured before the begining of the experiment to determine wavelength corrections and the instrumental contribution to the peak-profile for structure solution or Rietveld refinement. The standard analysis will take the same time as a sample or more, on average 8-14h to LaB6 and 6-8h. In the case of cryogenic experiments, you need to add 2h to heat the cryostat to room temperature and replace your sample. In the case of the in situ measurement with furnace and Mythen detection, the kinetics experiments will determine the experimental time (temperature range, heating rate, isothermal treatments, and number of XRD patterns acquired). However, it is important to consider that the furnace takes 40 min to cool down to room temperature. However, the Mythen detector is significantly faster with patterns attainable in few minutes.

# HOW TO CITE THIS BEAMLINE

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.

# 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.

MORE PUBLICATIONS

XPD

Anchieta, C. G. ; Assaf, E. M.; Assaf, J. M.. Effect of ionic liquid in Ni/ZrO2 catalysts applied to syngas production by methane tri-reforming, International Journal of Hydrogen Energy, v. 44, n. 18, p. 9316-9327, 2019. DOI: 10.1016/j.ijhydene.2019.02.122

DXAS   XAFS2   XDS   XPD

Resende, K. A.; Braga, A. H.; Noronha, F. B.; Hori, C. E.. Hydrodeoxygenation of phenol over Ni/Ce1-xNbxO2 catalysts, Applied Catalysis B-Environmental, v. 245, p. 100-113, 2019. DOI: 10.1016/j.apcatb.2018.12.040

XPD

Aguilera, L. J. ; Palacio, L. A.; Faro Jr., A. C.. Synthesis of NiAl layered double hydroxides intercalated with aliphatic dibasic anions and their exchange with heptamolybdate, Applied Clay Science, v. 176, p. 29-37, 2019. DOI: 10.1016/j.clay.2019.04.021

XAFS2   XPD

Blanco, H. ; Lima, S. H. ; Rodrigues, V. O. ; Palacio, L. A.; Faro Jr., A. C.. Copper-manganese catalysts with high activity for methanol synthesis, APPLIED CATALYSIS A-GENERAL, v. 579, p. 65-74, 2019. DOI: 10.1016/j.apcata.2019.04.021

XPD

Leal, G. F.; Lima, S. ; Graça, I.; Carrer, H. ; Barrett, D. H.; Teixeira-Neto, E.; Curvelo, A. A. S.; Rodella, C. B.; Rinaldi, R.. Design of Nickel Supported on Water-Tolerant Nb2O5 Catalysts for the Hydrotreating of Lignin Streams Obtained from Lignin-First Biorefining, ISCIENCE, v. 15, p. 467, 2019. DOI: 10.1016/j.isci.2019.05.007

XPD

Lino, A. V. P.; Calderon, Y. N. C. ; Mastelaro, V. R.; Assaf, E. M.; Assaf, J. M.. Syngas for Fischer-Tropsch synthesis by methane tri-reforming using nickel supported on MgAl2O4 promoted with Zr, Ce and Ce-Zr, Applied Surface Science, v. 481, p. 747-760, 2019. DOI: 10.1016/j.apsusc.2019.03.140

MORE PUBLICATIONS