Publicado em 26/04/2013
Science, em 26/04/2013
Nearly 30 years ago, Ricardo Rodrigues helped build a synchrotron from scratch.
That was no mean feat, as the young engineer at the University of São Paulo and his Brazilian colleagues were hampered by unstable funding and a shortage of trained personnel. Switched on in Campinas, Brazil, in 1997, the machine, known as UVX, was more artisanal than state-of-the-art. But Rodrigues, now head of engineering at the Brazilian Synchrotron Light Laboratory (LNLS), which houses UVX, won’t have to rest on that laurel: He’s getting a second chance to build his dream machine.
Early next month, LNLS scientists will break ground on Sirius, a synchrotron x-ray source whose energy and brightness will rival those of the best machines in the world. The $330 million initiative is the latest sign that Brazil is “taking the lead” in Latin American science, says Galo Soler-Illia, a chemist at the University of Buenos Aires and a member of Argentina’s National Atomic Energy Commission.
While other countries in the region shy away from huge investments in science, “these guys [in Brazil] are just building it,” says Soler-Illia, who served on LNLS’s scientific committee in 2011 and calls Sirius a “bright star” for Latin America.
In many ways, UVX was a more daunting challenge. It had to be conjured from thin air. “When we started building [UVX], we had five people in the country that had used synchrotron radiation. I was one of them,” says Rodrigues, who had spent time at DESY in Hamburg, Germany, while a postdoc at King’s College London in the 1970s. Lacking the financial and scientific resources to recruit foreign researchers to work on UVX, Rodrigues hired mostly young Brazilian scientists and engineers looking for their first jobs out of university. “They had to learn by doing,” he says. Skyrocketing inflation back then made it prohibitive to buy equipment from overseas, and local industry lacked the technical skills to manufacture items such as magnets and vacuum lines. So Rodrigues and his team constructed the machine by hand.
Their labors paid off. Scientists have traveled from as far away as Germany and Norway to use Latin America’s only synchrotron.
But most of UVX’s 1500 or so users a year hail from Brazil. Their primary research interests are in fields that have long benefitted from synchrotrons, such as materials science, condensed matter physics, and structural biology. Powerful oil companies like Petrobras and Braskem also rely on UVX for R&D.
Even as its local user community grew, UVX, a 1.4-GeV machine, diminished in scientific relevance. “It’s a second generation machine,” explains LNLS Director José Roque, a physicist. “It has relatively low energy, a large emittance, and thus a low brightness,” making it impossible to keep up with modern third-generation machines in areas such as 3D nanoscale imaging. As a result, many Brazilian scientists who cut their teeth on UVX now go abroad to push their research forward—the type of brain drain that UVX was supposed to help staunch.
LNLS realized that the generation of Brazilian scientists who came of age at UVX had outgrown the machine. In 2009, the lab asked Rodrigues, then running his own struggling technology company, to return and build a bigger and better synchrotron. Brazil’s science ministry has come up with the lion’s share of funding; Roque hopes to secure additional support from other agencies and companies like Petrobras.
With a diameter of 165 meters, Sirius will be five-and-a-half times the size of UVX. And its 3 GeV energy will put it on par with machines like Diamond Light Source in the United Kingdom and SOLEIL in France. With respect to emittance, Sirius will outshine its rivals. Low emittance means a narrow and bright x-ray beam that is more useful for imaging the nanostructure of materials ranging from oil to bacteria to fossils. Sirius will boast one of the lowest emittances in the world: 0.28 nanometer-radians. For scientists accustomed to UVX’s 100 nanorads, it will be like “going from an old TV to an HDTV set,” says LNLS Scientific Director Harry Westfahl. “All of a sudden you see everything more bright[ly].” After finishing a postdoc at the University of Illinois, Urbana-Champaign, Westfahl returned to his homeland in 2001 to head LNLS’s theory group. He’s now overseeing construction of Sirius’s first 13 beamlines. (Ultimately, the machine will have room for about 40.) He hopes that their sophisticated end stations—some of which are under construction for UVX—will entice more overseas Brazilian scientists to come home. Scientists from across Latin America are expected to flock to the new facility as well.
First, however, Rodrigues and his colleagues must summon their ingenuity and audacity a second time.
The optics required for such a low-emittance machine are “on the edge of what is able to be done nowadays,” Westfahl says. And the Sirius team must hire an army of scientists to meet its ambitious target of hosting its first users in 2017. The tasks ahead are “practically Olympic,” Soler-Illia says. The LNLS team will rise to the challenge, predicts Chi-Chang Kao, director of the SLAC National Accelerator Laboratory in Menlo Park, California. “They’ve done it before,” he says. “It’s just a much bigger scale this time around.” As for UVX, Rodrigues feels attached to his firstborn. While “Sirius can do all [that UVX] does much better,” he says, “it would be nice if we could keep [UVX] running somewhere else,” perhaps by moving the storage ring to another country that wants to kickstart its own synchrotron science program. “I would be very happy with that.”