SESAME Synchrotron's Battle for Light
In Jordan, a particle accelerator struggles to create a photon beam
Photo: Joseph Zakarian
Three years ago, Amor Nadji and three young engineers piled into a van in Amman, Jordan, and drove 30 kilometers northeast to the city of Zarqa. Their route took them past faded, sand-colored buildings and empty lots where sheep grazed on patches of grass and low brush.
The shops and apartment buildings gradually thinned out, and the van entered an industrial ghetto of warehouses. Behind one set of padlocked doors, about 100 plywood boxes and metal equipment racks stood coated in a thick layer of dust. Carefully packed away in those boxes was the collected hardware of a vintage synchrotron. The engineers’ mission was to salvage the then-25-year-old particle accelerator and turn it into a first-rate machine. This supermicroscope, called SESAME (for Synchrotron-light for Experimental Science and Applications in the Middle East) would enable scientists from Jordan and nearby countries to investigate the atomic structure of different materials. The engineers’ hope was that SESAME would revitalize Middle Eastern science and encourage friendly encounters between otherwise factious neighbors.
But first they had to navigate the plywood labyrinth of dust and decay. A decade before, their particle accelerator had narrowly escaped being sent to a scrap yard in Germany. The machine, then called Bessy, had had a research program in full swing. But after the Berlin Wall fell in 1989 and the country reunified, the German government found itself paying for one synchrotron light source too many. By the end of the ’90s Bessy faced dismantlement.
Around that time, four physicists working in Europe got a wild idea. CERN, the European Organization for Nuclear Research, had been built to encourage basic science after World War II and to help heal Europe’s fractures. Maybe a defunct German synchrotron could do the same for the Middle East, the physicists thought. They asked Germany to donate Bessy to the region. The machine could help spur collaborations, they argued: Israeli scientists searching for new materials could run experiments next to Iranian biomedical researchers imaging proteins while Palestinian environmental scientists analyzed rock samples across the hall. The rest of the world, they pointed out, had built more than 60 such facilities, while the Middle East had none.
The four physicists got their approval. ”It was one of the best [synchrotrons] in the world at the time,” says Herman Winick, who was then on Bessy’s board. ”They were going to call a junkyard dealer and cut it up and sell it as scrap metal. I wanted to convince them that we should offer it as a gift.” They set up a council to find Bessy a new home. Seven countries lobbied to get the machine, but Jordan won; its political regime was considered more stable and open to all visitors. The council recruited a fledgling staff, and the 13 young engineers were sent off to Europe for training.
In 2002, a ship pulled into Aqaba’s harbor carrying the boxed-up Bessy, and Jordan got the makings of a synchrotron. But rebuilding a machine that was originally 64 meters in circumference is no simple affair. There was no place to set up the machine, and nobody to run it. Khaled Toukan, the chairman of the Jordan Atomic Energy Commission and SESAME’s director, convinced King Abdullah II to donate a plot of land and build a hall for the synchrotron.
Two years passed before the team was ready to tackle the hardware. Nadji, SESAME’s technical director, recalls facing the warehouse with trepidation. ”This technology was completely new to this region, and my team was not very experienced,” he says. ”I suddenly had to be a specialist in everything.” Among his colleagues, he alone had helped build a synchrotron before—Soleil, a new machine outside Paris. There, pristine laboratories full of oscilloscopes and probes enabled him to diagnose problems quickly and easily. Here, nothing of the sort existed. That didn’t faze SESAME’s staff. Arash Kaftoosian, an engineer from Iran, approached the project ”like a puzzle,” he says. ”We used our imaginations to figure out how it all might fit together. But sometimes it seemed harder than if we were building it from scratch.”
Indeed, SESAME’s engineers, who hail from Iran, Pakistan, and the Palestinian territories, as well as Jordan, have been handed an almost impossible task. The equipment has become seriously dated, outstripped by the march of technological progress and aged by dust, heat, and time. Somehow, these young recruits must transform the mass of parts into a world-class laboratory so alluring that scientists from across the Middle East will set aside their grievances and build professional relationships at SESAME’s workstations. The staff has had to do so in the face of apathy from their home governments and a mere trickle of funding for the new facility.
Nadji and his crew collected about 20 of the boxes from the warehouse in Zarqa and brought them back to Allan, a small community in the rolling, tree-covered hills outside Amman. A brand-new, empty white building on a bare plot of land awaited them. Despite the political and financial challenges, the team was optimistic. The project seemed difficult but straightforward—take a good, working machine and reconstruct it. None of them imagined that two years later, they’d just be getting started.
On a sunny morning in May 2009, SESAME’s engineers settle into their labs to finish soldering circuit boards for the synchrotron’s new control system and power supply.
Outside, palm trees jut out of the tilled soil like sentries, and a scraggly patch of chrysanthemums bake under the cloudless sky. Students at the university next door peek through SESAME’s gated fence as they wait for the local bus to arrive. A rooster belts out its morning salute.
Seadat Varnasseri, head of SESAME’s power supplies and diagnostics, walks through the cavernous central hall and inspects a few boxes draped in plastic tarps. Rays of sun pour in through skylights and reflect off the shiny blue floor. The hall is clean and sleek, like a newly built Olympic arena.
Along the side of the main hall, a dozen bright orange cabinets stand on pallets amid crumpled sheets of plastic. Bundles of gray cords and wires droop from the cabinets, their ends cut off and dangling in midair. A vanilla-colored telephone receiver perches on the side of one control center, and the stout bulge of a CRT screen protrudes from another.
Varnasseri sometimes comes here to scavenge a spare knob for a new diagnostic tool he’s building. He admires the rows of square buttons lining a control panel, each with a label printed neatly in German. ”I guess this could be a nice museum,” says Varnasseri as he sizes up the racks, each one a carrot-colored relic that only the late 1970s could have produced.
The light streaming into the hall casts a soft gleam on the lone object in the center of the room: a maroon disc anchored upright like the face of a clock. The disc, 2.3 meters across, is the microtron, the ignition system for a synchrotron. The microtron’s job is to inject a burst of electrons into the synchrotron’s two nested, doughnut-shaped rings. Electrons will accelerate inside the first ring before entering the second one, where they will give off photons. These photons will have wavelengths far smaller than what ordinary microscopes can produce. By generating light with wavelengths of about 10-6 meters, a synchrotron can easily image a virus, and at 10-11 meters, researchers can see atoms.
The engineers have spent a year and a half trying to coax the microtron into producing an electron beam. It’s a tricky process. First, an electron gun must fire: A 2-microsecond microwave pulse bombards a cathode, causing its surface to emit some electrons. These electrons must then enter a cavity that will be fed with 3-gigahertz radio waves to speed up the electrons. An electromagnet should generate a magnetic field that repels the electrons and causes them to spiral outward. The electrons should then race around inside the microtron, passing through the initial cavity and collecting more energy each time. After completing 42 laps, the electrons should emerge from the microtron as a 22-megaelectron-volt beam. (A megaelectron volt, by the way, is the unit of energy commonly used in particle physics, equivalent to 1.6 x 10-13 joules.)
But the microtron has problems. For one, the device must be kept under a 10-3 pascal vacuum, but every cable and O-ring seal in the vacuum system has corroded with age. In addition, every circuit board in the control system contains obsolete transistors, so the crew has had to rebuild the control system from scratch. ”Think about it—we had a 20-year-old computer control system. Computers change every week!” Varnasseri says with a grin, pointing at the dusty racks.
To get even this far, the engineers had to decode the clues contained in the boxes they’d received from Germany. ”At first we were in the dark,” Varnasseri says. The staff had all the original paperwork for the hardware, but later changes and upgrades had been documented in stacks of handwritten notebooks—in German. They spent weeks sitting in a small, unheated warehouse next to SESAME’s main hall, poring over the boxes. Nadji recalls their fingers stiffening with cold as they searched for clues to Bessy’s last working configuration. ”I had to convince myself that it was worth it to move the equipment to the main building,” Nadji says. To put it more bluntly, he wasn’t confident that the microtron could ever get built.
A picture of the original machine started to emerge from the electronics, magnets, and girders that surrounded them, and soon the assembly began for real. The engineers set up the microtron on a wooden bench in the main hall. They ran exhaustive tests on its vacuum pumps, radio-frequency generator, and electromagnets; all seemed to be in working order.
The staff now awaits a few missing pieces—new transistors for the electron gun and the diagnostic systems and a radiation monitor to help ensure that once the machine fires, the staff will be safe. Across the wide, sun-dappled hall, plywood boxes, each the size of a large refrigerator, hold the beam lines that will eventually deliver light to experimental stations. Top-notch synchrotron facilities donated the equipment in anticipation of the day when SESAME’s brilliant rays will be aimed at samples brought in by biologists, archaeologists, and other investigators from across the Middle East.
What’s missing is everything in between. The engineers have the electron source and the infrastructure to deliver photons to the experimenters. But they don’t have a storage ring, the crucial apparatus needed to generate photons in the proper portions of the electromagnetic spectrum, a million times as bright as sunlight. Without a storage ring, SESAME is like a race car without an engine.
But the engineers keep working. The microtron is almost ready to be switched on. For the moment, the excitement of nearing that milestone overshadows the staff’s deep uncertainty about the machine’s ultimate fate.
At 5 o’clock on 13 July, Nadji asks most of his staff to go home for the evening. It’s time to test the microtron, and only the five people he needs to run the machine stay behind.
Nadji is nervous. They are about to find out whether their cautious reconstruction mimics Bessy closely enough to work. Maher Attal, an accelerator physicist from the Palestinian territories, sets up the microtron using the parameters they have on file. He triggers the electron gun. Nothing happens.
Perhaps something went wrong with the electromagnet, they think, so they turn its power supply off and back on again. They adjust the frequency of the radio waves entering the accelerating cavity—up, down, up some more, down some. Each adjustment changes the amount of energy transferred to the electrons and alters their orbits. They take a closer look at the deflection tube, which shields the electrons from the magnetic field to temporarily straighten out their path. They move the tube inside the microtron. By about 7 o’clock, the team decides that the electron gun isn’t sending electrons hurtling through the deflection tube. Why not?
Two more hours go by. Darweesh Foudeh, a radio-frequency engineer from Jordan, swaps out a few burned-out transistors. Then Nadji realizes that the electromagnets have probably warped over time, so the settings used by Bessy’s last operators won’t work. Deviations in the magnetic field inside the microtron are probably causing electrons to fly off their intended path. So Attal adjusts the trim magnets, which are corrective coils that can compensate for small irregularities in the main magnetic field.
”At the end of the microtron, we put a fluorescent screen and a camera,” Nadji recalls. The camera, sitting outside the microtron, points directly at the screen. At 12:34 a.m., a splotch materializes on it. The first electrons have emerged. Nadji remembers the moment vividly: ”We could see on our monitors the shape of the beam. We finally knew. We created the beam, circulated it, and extracted it from the microtron.”
They test it a few more times, to check that they can repeat the miracle. By 3 a.m. they have their proof. The microtron is producing a rectangular beam, approximately 2 by 4 millimeters, neat and clean and with no distortion.
The moment validates all the time and energy they’ve sunk into the touchy old machine. ”To be honest, we wanted to show we were able to do it,” says Kaftoosian, who is in charge of the radio-frequency group at SESAME. ”I’m doing something new for my community. If I go to the United States and work on a synchrotron, okay, then you’re working there. But you’re not contributing to new things like SESAME, which is willing to go for peace and for solving political problems.”
That day in July may well be the most exciting at SESAME so far. But they take no time to celebrate. The political infighting that the synchrotron was intended to help solve is now threatening to unravel its progress—and to undermine its very existence.
SESAME had never been an easy sell. Back in the late ’90s, when the European physicists Herman Winick, Gustaf-Adolf Voss, Sergio Fubini, and Herwig Schopper first dreamed up the idea of SESAME, they immediately faced obstacles. The gift they wanted Germany to make was valued at around $6 million or $7 million—but packing it up carefully, with the help of Russian specialists from Novosibirsk, would cost about $600 000. Schopper had less than four months to come up with the cash.
Schopper, formerly a director general of CERN, approached UNESCO first. After World War II, UNESCO had set up the framework for CERN, and Schopper believed the organization could also broker the initial talks between the Middle Eastern countries he hoped to bring on board. Together, Schopper and UNESCO’s then assistant director-general for the natural sciences, Maurizio Iaccarino, quickly pulled together a coalition to sponsor SESAME. The group included Bahrain, Cyprus, Egypt, Iran, Israel, Jordan, Pakistan, the Palestinian Authority, and Turkey.
Getting the members to contribute their share of expenses proved harder. Schopper recalls collecting a mere $200 000. He pleaded with his German contacts to lower the tab, he says, ”but the government had given me a hard condition. I had to come up with the money.” In the end, UNESCO stepped in with the remaining $400 000. ”The project would have collapsed without their support,” Schopper says.
Since then, the synchrotron’s directors have coaxed about $2 million out of its members for an operating budget that pays salaries for 22 people, keeps the building running, and allows small equipment purchases. But Nadji needs another $30 million to build the storage ring and finish the project. Bessy came with a storage ring, of course, but SESAME’s team envisioned something far better. In order to court prospective users, in particular Middle Eastern biologists, the staff had agreed to upgrade the synchrotron to run at a higher energy of 2.5 gigaelectron volts, instead of Bessy’s 0.8 GeV. The larger the circumference of the storage ring, the higher the energy it can accommodate—which means greater resolution for the images the synchrotron can produce. At 133 meters, SESAME’s planned circumference is twice that of Bessy’s.
With a ring that large, SESAME could generate hard X-rays and compete with other synchrotrons around the world. But generating such intense energy levels requires expensive and complex equipment: To control the electrons in that storage ring, specialized magnets must force the charged particles to maintain a circular path in a tight, compact beam. Other magnets, called wigglers and undulators, must deflect the electrons and cause them to lose energy, which they emit as light. The electrons should then pass through radio-frequency cavities to replace the energy they just lost.
So far, the members haven’t paid. ”I’m coming from Soleil, where the machine itself was maybe €150 million. Here we’re talking €20 million,” Nadji says, a note of frustration creeping into his voice. To him, the case for the storage ring is obvious. ”Every year the demand at synchrotrons is always twice the opportunities,” he explains, and so only half of the research teams that apply for time on a beam line actually get it. Many countries, including Brazil, India, Taiwan, and Thailand, have addressed the access problem by building their own synchrotrons.
But there’s a bigger issue at work here, says Hafeez Hoorani, SESAME’s scientific director and a research director at the National Centre for Physics at Quaid-i-Azam University, in Pakistan. ”The more fundamental problem is how much Middle Eastern countries are investing in science,” Hoorani says. According to data from UNESCO, Arab states spend, on average, 0.2 percent of their gross domestic product on research and development, while the world’s average is 1.7 percent. (Israel is the exception in the Middle East, with 4.7 percent of GDP dedicated to R&D.)
Nadji estimates that SESAME’s engineers have about a year of work left before they run out of things to do. They’re now testing the booster ring, which accepts the electron beam from the microtron and accelerates it before transferring it into the storage ring. They hope to produce a beam that travels from the microtron out through the booster ring by the end of the year.
Reaching that landmark may be a mixed blessing. Without the storage ring, the talented young engineers will have nothing left to do, and Nadji fears that his dedicated, hardworking team will start to defect.
They would be departing just as the first signs emerge that SESAME is indeed becoming a worthy descendant of CERN. ”For me the nicest thing is seeing people coming together through SESAME and seeing Palestinians and Israelis sitting and talking together,” Hoorani reflects. Eliezer Rabinovici, a physics professor at Hebrew University, in Jerusalem, concurs. ”As a string theorist, I work on parallel universes,” he says. ”I was always curious what a parallel universe was like, and now I know. I’m living in one when I go to SESAME meetings.”
SESAME’s situation may be about to change. Last month, Rabinovici talked Israel into pledging $1 million a year for five years—but only if four other members also do so. Two members have signed on already, and Sir Christopher Llewellyn-Smith, president of the SESAME council, is optimistic that others will also join in soon. Nadji says he’ll continue to push his team to finish the job. ”We’ve come this far,” he says. ”I have to believe we’ll get there.”
This article originally appeared in print as "Open Sesame?"