New beamlines at Sirius make more possibilities available to Brazilian science

The fourth-generation particle accelerator installed at the Brazilian Synchrotron Light Laboratory (LNLS) was the topic for the 4th FAPESP Lecture 2023. LNLS Director Harry Westfahl Junior described the facility and the research opportunities it offers. He also announced the third call for proposals.

By José Tadeu Arantes  |  Agência FAPESP – With a circumference of 530 meters, Sirius, Brazil’s fourth-generation synchrotron light source, is the nation’s largest and most important piece of science infrastructure. It is one of only three 4G synchrotron radiation facilities in the world. The others are in Sweden and France. More are under construction in China and other countries where scientific research is highly advanced. 

Synchrotron light is a type of high-flux high-brightness electromagnetic radiation encompassing a large proportion of the spectrum from infrared through ultraviolet to X-rays. It penetrates matter and enables scientists to study the molecular composition and atomic structure of materials of all kinds.

Located in the Brazilian Center for Research in Energy and Materials (CNPEM) in Campinas, São Paulo state, and funded by the Ministry for Science, Technology and Innovation (MCTI), Sirius is designed to be a national laboratory that can be used free of charge for public-interest scientific research. Companies may use it for private-interest research but must pay to do so.

To talk about Sirius and the vast array of current and potential applications, FAPESP brought to its auditorium physicist Harry Westfahl Junior, head of the Brazilian Synchrotron Light Laboratory (LNLS), where Sirius is installed. The 4th FAPESP Lecture 2023, entitled “Sirius, a New Era for Brazilian Science with a Fourth-Generation Synchrotron”, took place on August 25 and can be watched on Agência FAPESP’s YouTube channel.

Westfahl Junior announced that the third regular call for proposals for Sirius’s first ten experiment stations is open. Researchers in Brazil and other Latin American and Caribbean countries have until September 6 to submit projects. Those whose projects are approved can apply for funding to use Sirius and for travel to Campinas.

He also exemplified the uses of each of the beamlines available for regular competitive tendering or now being commissioned (four more are under construction). The results range from visualization of active protein sites and how electrons are transferred from or to them by oxidation or reduction processes, to analysis of materials subjected to extreme temperature, pressure or magnetic field conditions so as to display novel physical or chemical properties, as in the case of superconductors, which conduct electric current without resistance.

An important advantage of Sirius and other synchrotron radiation facilities is that they allow scientists to perform experiments in situ in order to observe how the structure of a material changes in response to variations in temperature, pressure, mechanical stress, electric or magnetic field, and chemical environment, among other factors.

New beamlines

The four new beamlines for which proposals can be submitted in this call extend the experimental possibilities offered by Sirius still further. According to Westfahl Junior, other types of experiments can be conducted to complement existing ones. “The Cedro [Cedar] beamline will offer new possibilities for experiments in biophysics. The Sabiá [Song Thrush] beamline will offer new possibilities to explore mechanisms that confer magnetic properties on materials. The Mogno [Mahogany] beamline, the most powerful in terms of energy, will offer unprecedented capacity in X-ray tomography, benefiting several knowledge areas. The Paineira [Silk Floss Tree] beamline will extend our capacity in crystallography and offer new possibilities for soil mineralogy and real-time investigation of the atomic structure of catalysts,” he said.

In addition, the Ipê [Trumpet Tree] beamline, which is already open for use by researchers, will offer a new technique known as resonant inelastic X-ray scattering (RIXS). “This technique is available only in a few synchrotrons worldwide. It can be used to show how electrons organize to confer properties from catalytic centers in biomolecules to formation of exotic states of matter, as in superconducting materials,” he said.

Particle accelerator

Sirius is fundamentally a particle accelerator. Westfahl Junior explained the difference between Sirius and other particle accelerators, such as the Large Hadron Collider (LHC), a massive facility operated by CERN on the Franco-Swiss border. In the LHC, two beams of hadrons, mainly protons, race around a vast ring in opposite directions. They are accelerated by magnetic fields to extremely high levels of energy and collide. Scientists analyze the particle showers produced by these collisions to discover the properties of the matter that can exist at such high energy levels, validating or refining theoretical schemes such as the Standard Model and reconstituting situations thought to have occurred in the primordial universe.

Sirius is a different kind of accelerator. “It’s not designed to produce collisions but to accelerate electrons almost to the speed of light in order to produce electromagnetic radiation. The accelerated electrons emit photons, which are guided by the instrument to the beamlines,” Westfahl Junior said.

The radiation is filtered at different wavelengths and pointed at samples of interest. Depending on the wavelength and sample, the radiation may or may not be absorbed by the material, revealing its structure and composition. “Visible light has energy of about 2 electron volts [eV], but Sirius produces radiation ranging from far below 1 eV to many thousands of eV,” he said.

Low levels of energy in the infrared band enable the “signatures” of chemical bonds to be identified. Levels slightly higher than that of visible light provide information on how electrons are arranged in the material. Levels far higher than thousands of eV, especially in the X-ray band, allow scientists to perform a wide array of experiments.

All this technology is deployed to condense electrons and produce the finest possible beams so that matter can be mapped at the nanometric scale. “In 4G synchrotron accelerators, the beam is much tighter than in previous generations, and the coherent fraction is much larger. The new possibilities available to us derive from this enhanced coherence. Another important point is that it isn’t enough to produce a tight beam of electrons. The beam also has to be stable, in order to be able to keep traveling through the ring all day long, every day of the week, without varying more than a few hundred nanometers,” he said.

An example of cooperation

Westfahl Junior’s presentation and the Q&A session furnished comprehensive information on Sirius, from the physics of synchrotron radiation to the profile of the researchers and technicians who staff the facility, from funding to the conditions for submitting research proposals, and from management’s openness to foreign teams to the diplomatic capital this science infrastructure represents for Brazil.

The session was opened by FAPESP’s CEO, Carlos Américo Pacheco, who highlighted the role of the pioneers who built Brazil’s first synchrotron light source and the contribution made by local industry in making its components. The moderator was Oswaldo Baffa Filho, a professor at the University of São Paulo’s Ribeirão Preto School of Philosophy, Sciences and Letters (FFCLRP-USP). FAPESP President Marco Antonio Zago, who was in the audience, attributed the success of the project to cooperation among the scientific community, private enterprise and government, adding that in his view this kind of cooperation is all too rare.

For more information about Sirius, visit CNPEM’s portal. 

More about this and other events in the series FAPESP Lectures 2023 can be found at: fapesp.br/conferencias2023.