by Benjamin White

BESSY is big - that's the overwhelming notion that strikes visitors to the giant laboratory in Berlin. Past security and through the postmodern lobby lies the control room, which looks eerily like the control panel of the Death Star. A few more doors and a spiral staircase lead to the floor of the Superdome-sized facility, where over 40 groups work fervently – time at BESSY is a rare and precious commodity. For Vincent Roberts, a senior studying physics at OU, it's just another day at work.

The Berlin Electron Storage Ring Society for Synchrotron Radiation (abbreviated in German to BESSY) opened in 1998 as a replacement for the original BESSY, which was founded in 1979. BESSY II, as the current incarnation is officially known, looks like a giant chocolate doughnut from above – its essence is a surprisingly thin tube which makes an enormous ring with a circumference of 240 meters. Through this tube travel hundreds of bunches of electrons fast enough to create light – many kinds of rare light – that scientists from across the world clamor to use in their research.

Roberts, barely 21 years old, is spending the summer studying at the Institute for Physics at Humboldt University in Berlin. He studies condensed matter under NQPI member Dr. Saw-Wai Hla at OU, and he does not take his good fortune for granted.

“I feel like many of the undergrads don't get a chance to go abroad very often,” he said. “It's a much better opportunity.”

BESSY is one of the most advanced labs of its kind in the world, and Dr. Antje Vollmer, a surprisingly young-looking woman, is a senior scientist responsible for helping dozens of visiting researchers use the equipment at any given time, even if they call in the wee hours of the morning. Vollmer describes her daily duties as 10-20% engineering, 10% research, 10% manual work and 50% kindergarten, and she seemed perfectly comfortable explaining the intricately complex machine to someone who had not cracked a science textbook since the Bush administration.

“We use electrons from an electron gun. It's actually not like a Star Wars type thing, but just a filament” she said.

From there, the electrons head to the microtron, a smaller version of BESSY's premier ring, to accelerate to 50 megavolts. Then, the electrons, usually in bunches, move to the main accelerator, the synchrotron where they get accelerated to 1.6 gigavolt and from there into the storage ring. In most circumstances, the ring contains 340 bunches of electrons in a space that could hold 400, creating a gap. In the gap travels one electron bunch, which researchers use as a timer. BESSY is the only facility of its kind in the world where scientists can obtain measurements with X-ray of variable polarization in femtoseconds (10-15), and researchers can also obtain special definition down to a picometer (10-12) Users can tinker with energy, polarization, temperature and many other variables to their liking.

“You can choose whatever you like at any time you like, without disturbing the system,” Vollmer said.

The electrons never leave the storage ring, but the light they emit at such high speeds travels to 46 “beam lines,” thin tubes that emerge from the giant ring to transport light to research stations. Aluminum foil covers virtually every surface of each beam line, making the scene look even more like science fiction. The foil helps evenly disperse heat when the beam line needs ‘baking’ to 150°C for a day or two to achieve ultrahigh vacuum.

Only one in three research teams vying for a week-long slot of “beam time” at BESSY will receive it. Though private corporations can buy research time (usually at the rate of 250 euros per hour, depending on the desired beam), BESSY is free to scholastic researchers working with grant money, and international referees determine which teams receive beam time.

“We do all sorts of unconventional things for a research facility like this,” said Vollmer, attaching her radiation badge.

Scientists from disciplines ranging from archeology and art to biology and medicine use BESSY’s beam lines to conduct their research. One of the more unusual projects involved the “Sky Disk of Nebra,” an ancient bronze disk which depicted the night sky and a boat with gold inlays. The 3,500 year-old artifact is believed to be the oldest depiction of the night sky. BESSY helped scientists blast the artifact with harmless synchrotron radiation-driven X-ray fluorescence, a tool that can determine the exact composition of materials without damaging or affecting them in any way. Scientists could then accurately match the materials to a geographic area of origin.

The results: the majority of the gold inlays were found to have originated from Austria. The boat, which already stood out aesthetically from the rest of the disk, was found to be crafted from gold from either Romania or Stonehenge. These findings shed light on trade and culture sharing in Bronze Age Europe, and also opened a multitude of questions for archeologists and historians.

BESSY’s bread and butter, though, is material science and data storage study. Much of the research currently conducted by the lab’s 75 in-house scientists surrounds solar cells. Vollmer and other scientists study the materials that convert light to energy by using X-ray spectroscopy to understand the most efficient way to move the charges in and out of the materials. This research could one day lead to “electronics with the personality of a silicon chip and the consistency of a plastic bag,” according to Vollmer.

BESSY II’s opening in 1998 cost roughly 100 million euro. It replaced the original BESSY, located in Wilmersdorf, which is now part of the SESAME synchrotron facility in Jordan. The original lab housed pioneering work on spin-polarized photoemission.

Though Roberts will probably not receive any experience on the beam lines, he will assist researchers and laboratory staff at BESSY while working at nearby Humboldt University. His group uses scanning tunneling microscopy to study materials which could lead to the next generation of solar cells and superconductors. Though he vaguely know he wants to enter the field of medical physics, Roberts has no idea where he will attend graduate school.

Dr. Vollmer took a personal interest in Roberts, making sure he makes the most out of the time spent at the giant playground for researchers. Though she admits the 24/7 pace is hectic and “everyone is stressed,” Vollmer enjoys her job.

“It’s fun – Tinker Toys for big kids.”