# OVERVIEW

BACK

The PGM (Planar Grating Monochromator) beamline is an experimental station dedicated to X-ray Spectroscopy in the soft X-rays (100 to 1500 eV) energy range, with applications to the study of the electronic, magnetic and structural properties of materials. It is well equipped with in-situ preparation facilities, making it particularly suited for surface science and thin films characterization. In addition to that, it is offers instrumentation for microscopy and photoemission on liquids.

PGM’s source is an elliptical polarization undulator with a 50 mm period (EPU50), which allows the photon polarization to be switched among linear horizontal, linear vertical or circular polarization. Its optics is based on a standard planar grating monochromator (PGM) equipped with a 1500 l/mm variable line spacing (VLS) diffraction grating. It serves two branches that operate independently but not simultaneously.

The beamline provides several experimental end stations to users. Systems are available for X-ray absorption and its variants (linear and circular dichroism), photoemission (XPS and ARPES), photoemission microscopy (PEEM), XPS on liquids and soft X-ray diffraction.

Furthermore, the beam line is equipped with a full featured in-situ preparation system, which allows the user to grow thin films and heterostructures by molecular beam epitaxy (MBE) with thermal evaporators and by pulsed laser deposition (PLD). The samples can then be transferred under ultra-high vacuum conditions and be characterized by the techniques available at the beam line.

# CONTACT & STAFF

Beamline Phone Number: +55 19 3512 1146

Coordinator: Julio Criginski Cezar
Number: +55 19 3512 1292
E-mail: julio.cezar@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.

• X-RAY ABSORPTION (XAS)
• X-RAY PHOTOEMISSION (XPS)
• ANGULAR RESOLVED PHOTOEMISSION (ARPES)
• PHOTOELECTRON EMISSION MICROSCOPY (PEEM)
• X-RAY CIRCULAR MAGNETIC DICHROISM (XMCD)

# LAYOUT & OPTICAL ELEMENTS

ElementTypePosition[m]Description
SourceInsertion DeviceInsertion Device U11A, APPLE II Elliptical Polarization Undulator (EPU50), built in-house, 50 mm period, 2.73 m long
M1Toroidal mirror13Au coated; water cooled
M2-GMonochromator15Au coated plane mirror and 1500 l/mm VLS grating
ESExit slit22-
M3a, M3bRefocussing toroidal mirrors29Au coated; used to switch between branches

# PARAMETERS

ParameterValueCondition
Energy range [keV]103 – 1500 eVLinear horizontal polarization
Energy range [keV]192 – 1500 eVLinear vertical polarization
Energy range [keV]127 – 1500 eVCircular polarization
Resolving power [E/$\Delta$E]1000 - 25000-
Beam size at sample [$\rm mm^{2}$, FWHM]0.1 x 0.5Vertical x horizontal
Flux at sample [ph/s]$10^{11}$ – $10^{13}$-

# INSTRUMENTATION

InstrumentTypeModelSpecificationsManufacturer
Superconducting magnet--$\pm 4 \rm T$ along the beam direction. Sample temperature between 10 and 420 KCryomagnetics Inc.
Electron Analyzer--150 mm radius hemispherical analyzer; CCD detector Energy resolution $\approx$2.5 meV; Angular resolution $\approx$0.1 degree; Sample manipulator with six degrees of freedom; Sample temperature between 15 and 420 K.Phoibos 150 SPECS
Photoelectron Microscopy--Fields of view from 100 down to $0.7 \mu \rm m$; Sample temperature from 90 up to 1400 K during measurements; Some possibilities for in-situ preparation (Ar sputtering and e-beam evaporation).P 90 SPECS
Electron Analyzer for liquids sample---Scienta
Diffractometer--4 degree of freedom diffractometerLNLS 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. The systems from SPECS GmbH run on the manufacturer software.

# 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 SAU Online portal. Learn more about how to submit a proposal here.

# 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

PGM

Fidelis, I.; Stiehler, C. ; Enderlein, C. ; Silva, W. S. e; Soares, E. A.; Shaikhutdinov, S. ; Freund, H. J. ; Stavale, F. L.. Electronic properties of ultrathin O-terminated ZnO (000(1)over-bar) on Au (111), Surface Science, v. 679, p. 259-263, 2019. DOI: 10.1016/j.susc.2018.10.007

PGM   XAFS2

Salcedo Rodríguez, K. L.; Bridoux, G.; Heluani, S. P.; Pasquevich, G. A.; Esquinazi, P. D.; Torres, C. E. R.. Influence of substrate effects in magnetic and transport properties of magnesium ferrite thin films, Journal of Magnetism and Magnetic Materials, v. 469, p. 643-649, 2019. DOI: 10.1016/j.jmmm.2018.08.065

PGM   XDS

Jesus, J. R.; Garcia, F.; Duque, J. G. L.; Meneses, C. T.. Study of exchange bias in single-phase Dy0.2Nd0.8CrO3, Journal of Alloys and Compounds, v. 779, p. 577-581, 2019. DOI: 10.1016/j.jallcom.2018.10.335

PGM

Carravetta, V.; Gomes, A. H. A.; Monti, S.; Mocellin, A.; Marinho, R. R. T.; Björneholm, O.; Agren, H.; Naves de Brito, A.. pH-dependent X-ray Photoelectron Chemical Shifts and Surface Distribution of Cysteine in Aqueous Solution, Journal of Physical Chemistry B, v. 123, n. 17, p. 3776-3785, 2019. DOI: 10.1021/acs.jpcb.9b00866

PGM

Fernandez, C. C.; Wechsler, D. ; Rocha, T. C. R.; Steinrück, H.-P.; Lytken, O. ; Williams, F. J.. Adsorption of Phosphonic-Acid-Functionalized Porphyrin Molecules on TiO2(110), Journal of Physical Chemistry C, v. 123, n. 17, p. 10974-10980, 2019. DOI: 10.1021/acs.jpcc.9b01019

PGM

Gonçalves, P. H. R.; Calil, L. ; Antoniazzi, I. ; Chagas, T.; Malachias, A.; Soares, E. A.; Carvalho, V. E. de; Miquita, D. R.; Paniago, R.M.; Silva, W. S. e. Experimental Realization of a Quaternary Bi-Chalcogenide Topological Insulator with Smaller Effective Mass, Journal of Physical Chemistry C, v. 123, n. 23, p. 14398-14403, 2019. DOI: 10.1021/acs.jpcc.9b01811

MORE PUBLICATIONS