A joint Fermilab/SLAC publication

issue 2

may 2011

volume 8dimensionsofparticlephysicssymmetry

symmetryA joint Fermilab/SLAC publication

volume 8 | issue 2 | may 2011

On the coverThis image represents data from experiments at SLAC’s Linac Coherent Light Source. Scientists used the light source to probe the structure of a protein complex called Photosystem I, which helps plants convert sunlight to fuel. X-ray laser pulses from the LCLS hit millions of tiny protein crystals at various angles and scattered into a detector, forming diffraction patterns. Scientists combined 15,445 of those patterns to get the 3-D visualization shown here. The colors and sizes of the spheres represent the intensities of the spots in the diffraction patterns. Researchers analyzed this information to come up with a low-resolution match to the known 3-D structure of the protein. The technique, which uses much smaller protein crystals than today’s methods, could allow scientists to decipher the structures of thousands of important proteins that are now out of reach, including many involved in treating disease. This research, reported in the Feb. 3, 2011 issue of Nature, demonstrates the evolving potential of light sources, powerful all-purpose tools for a wide range of research—and the ultimate “killer app” for particle physics technology. Image: Thomas White, DESY

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Editorial: Not for the Faint of Heart This past winter, the first one in Irasburg, Vermont, for my husband and me, was a record breaker: frigid, snowy, and endless. It has been an equally tough season for basic science, including particle physics.

Commentary: John GalaydaI got involved in particle accelerators because I wanted to work in an area that had the potential to have a positive impact on people’s lives. I have become a sort of light-source bum, working on the beautiful combination of physics and technology (and really every kind of creativity that goes into the planning, construction and operation) of light sources.

Signal to Background A saint goes underground at DESY; foreigner physicists get family treat-ment after Japanese quake; astronomy takes particle physics on a field trip; ALICE squeezes in; who needs James Bond when you have neutrinos?; letters; correction

symmetrybreaking A summary of recent stories published online in symmetry breaking, www.symmetrymagazine.org/blog/may2011

Shedding Light Light sources are the ultimate killer apps for particle physics technology. Their brilliant X-rays illuminate every aspect of the material world, from the inner workings of cells to the intricate dance of the electrons that create chemical bonds.

LBNE: The Inside Buzz on a New Science Project Planning and designing the $900 million Long Baseline Neutrino Experiment takes more than a village. It takes a hive’s worth of scientists, engineers, technicians, accountants, and other specialists of every stripe.

Eminently Noble When it comes to detecting neutrinos or particles of dark matter, four noble elements—helium, neon, argon, and xenon—stand out for their standoffishness.

Day in the Life: Science Fest Hammering nails with a banana to spark interest in science and technology

Deconstruction: Dark Energy Camera Goes to Chile Building and installing one of the world’s largest digital cameras for the most extensive galaxy survey to date involves scientists and manu-facturers from across the globe.

Accelerator Apps: Diapers In the United States, we buy more than 20 billion disposable diapers each year. That’s a lot of baby bottoms to keep dry, and parents every-where can thank particle accelerators for doing their part.

Logbook: Protein Structure In 1975, in a small hutch grafted onto an 80-meter accelerator ring, four young scientists demonstrated a new and much more effective way to decipher the structures of proteins. The key ingredient: light given off by a particle physics experiment.

Explain it in 60 Seconds: Synchrotron Radiation Synchrotron radiation is the light emitted by charged particles as they accelerate—whether they’re gaining speed along a straight line or traveling at a constant speed on a curved path.

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from the editor

SymmetryPO Box 500MS 206Batavia Illinois 60510USA 630 840 3351 telephone 630 840 8780 fax mail@symmetrymagazine.org

For subscription services go to www.symmetrymagazine.org

symmetry (ISSN 1931-8367) is published six times per year by Fermi National Accelerator Laboratory and SLAC National Accelerator Laboratory, funded by the US Department of Energy Office of Science. (c) 2011 symmetry All rights reserved

Editor-in-ChiefJudy Jackson802 754 9968

Deputy EditorGlennda Chui

Managing EditorKurt Riesselmann

Senior EditorTona Kunz

Staff WritersElizabeth Clements Calla Cofield Lori Ann White Rhianna Wisniewski

InternsCynthia HorwitzSara Reardon

PublishersKatie Yurkewicz, FNAL Farnaz Khadem, SLAC

Contributing EditorsRoberta Antolini, LNGSPeter Barratt, STFC Romeo Bassoli, INFNStefano Bianco, LNFKandice Carter, JLabLynn Yarris, LBNLJames Gillies, CERNSilvia Giromini, LNFYouhei Morita, KEKTim Meyer, TRIUMFPerrine Royole-Degieux, IN2P3 Yuri Ryabov, IHEP ProtvinoYves Sacquin, CEA-SaclayKendra Snyder, BNLBoris Starchenko, JINRMaury Tigner, LEPP Ute Wilhelmsen, DESYTongzhou Xu, IHEP BeijingVanessa Mexner, NIKHEF

Print Design and ProductionSandbox StudioChicago, Illinois

Art DirectorMichael Branigan

Designers/Illustrators Aaron Grant Brad NagleAndrea Stember

Web Design and ProductionXeno MediaOakbrook Terrace, Illinois

Web ArchitectKevin Munday

Web DesignKaren AcklinAlex Tarasiewicz

Web ProgrammerMike Acklin

Photographic Services Fermilab Visual Media Servicessymmetry

Not for the faint of heart

Winter in northern Vermont is not for wimps. This past winter, the first one in Irasburg for my husband and me, was a record breaker: frigid, snowy, and endless. On March 7, with the vernal equinox in sight, 32 inches of snow fell in six hours. Even on snowshoes, we sank to our waists on a trip to the post office. After that, it snowed every day, or so it seemed, all through March—five inches on the first official day of spring—and into April. Even the natives, stalwart weather stoics, began to grumble. Spring would never come.

It has been an equally tough season for basic science, including particle physics. As the budget battles raged in Washington and one continuing resolution followed another, national laboratory

directors wondered if the final appropriations would let them keep the lab doors open, the particle accelerators running, and the staff employed. It was hard to imagine, in these times, why any young American with a grain of sense would ever choose a career in particle physics.

Then, just as it seemed as if the long, bleak budget season would never end, came a sur-prise. Fermilab’s CDF experiment announced a bump in the data that might—might—jolt particle physics right out of the Standard Model and into a whole new view of the laws of physics. If it holds up, CDF’s bump might be the herald of a brand new force of nature.

All at once we remembered why a person with a grain of sense—and a passion for discovering nature’s secrets—would choose a life in particle physics. Yes, the budget process grinds on, yes the beloved Tevatron will soon shut down, but that bump got us through the winter. Even if it goes away, as bumps often do, it reminded us of the point of it all, of the thrill of the unex-pected and the extraordinary possibilities of scientific discovery.

Like winter in Vermont, particle physics is not for the faint of heart, but we recognize anew that it’s worth it. The weather forecast calls for possible snow in Irasburg tomorrow, but the daffodil shoots are up, and I don’t think they plan on going back.Judy JacksonEditor-in-chief

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commentary: john galayda

Adventures of a light-source bum

I got involved in particle accelerators as a grad-uate student because I wanted to work in an area that had the potential to have a positive impact on people’s lives in 10 to 20 years. Near the end of my PhD studies, I attended a talk by Herman Winick, who introduced the audience to synchrotron radiation sources and the research going on at the SPEAR ring at what is now the Stanford Synchrotron Radiation Lightsource, SSRL.

Of course I had been aware of SPEAR, because physicists had recently discovered the J/psi particle in collisions there. But this colloquium was my first introduction to synchrotron light sources, which use the light generated by charged particles accelerating around a ring to probe matter on a very small scale. At that time, light sources were generally small research facilities harvesting light from accelerators that were pri-marily used for particle physics, and SSRL was no exception. Herman described how scientists there had measured changes in the environ-ment of the iron atom in hemoglobin that occur when it picks up oxygen for transport in the bloodstream. Here was an accelerator used for physics research that could affect and improve people’s lives within my own lifetime. I wanted to work on that kind of thing.

SPEAR was designed to run as a particle phys-ics facility. Brookhaven National Laboratory’s Rena Chasman and Ken Green had recently proposed the first electron storage ring designed from the ground up to be a light source, optimized to pro-duce the brightest possible X-ray beam. When the time came for me to get a job, Green hired me in 1977 to work on the design and construction of this project, the National Synchrotron Light Source.

Even this designed-from-scratch light source relied heavily on the technology and experience developed at the world’s electron/positron collid-ers: ADONE, ACO, CESR, PEP, and PETRA. When I arrived at Brookhaven I got right into it, reading large numbers of reports from what is now SLAC National Accelerator Laboratory to get up to speed on the state of the art in accelerator design.

By the time we got the NSLS up and running, Claudio Pellegrini had arrived at Brookhaven from Italy’s Frascati National Laboratories to work on a colliding-beam proton machine for particle physics. Pellegrini got Brookhaven research-ers interested in free-electron lasers—a new generation of light sources that promised even greater brightness, as well as the ability to resolve processes that take place on ultrafast timescales—and we spent many late nights at

the 700 MeV Vacuum Ultraviolet Ring on FEL-related experi-ments. I learned techniques for storing more current in the NSLS rings from Flemming Pederson, who had applied these techniques to the Proton Synchrotron at CERN, the European particle physics facility.

I have become sort of a “light-source bum,” moving on to Argonne National Laboratory to build and operate the Advanced Photon Source there, and in 2001 to SLAC, which had resolved to pursue Pellegrini’s 1992 proposal to turn a 0.6-mile segment of the 2-mile-long linear accelerator into the world’s most powerful X-ray free-electron laser. This project, the Linac Coherent Light Source, opened for research in late 2009, on time and under budget, in what may be the smoothest startup ever for any large-scale accelerator facility. This could not have happened without the thorough under-standing of the linac developed during four decades of operation for particle physics and the skills developed in steering and focusing beams for the Stanford Linear Collider.

With the LCLS up and running, we have already started to design a major expansion, LCLS I I. Other free-electron laser projects are under way in Europe and Asia. All use concepts and hard-ware developed in the worldwide effort to produce more powerful accelerators for high-energy physics. Research on light-source technology has taken on a life of its own and is coming full circle. For instance, at DESY, the German national laboratory, the TESLA project was a striking example of a thoroughly integrated accelerator research program in pursuit of both particle physics and ultrafast science with X-rays. The TESLA Test Facility is now FLASH, a highly productive X-ray free-electron laser user facility that opened in 2005. Now DESY is collaborating on the construction of the European XFEL, whose operation starting in 2015 may inform the design of the proposed International Linear Collider for particle physics.

As for me, I am still a bum but a happy one, working on the beautiful combination of physics and technology (and really every kind of creativity that goes into the planning, construction and operation) of light sources.

John Galayda directed the construction of the Linac Coherent Light Source at SLAC National Accelerator Laboratory, and is now project director for LCLS II.

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signal to background

Saint protects European XFEL tunnel To the sound of a traditional German miners’ song, the two tunnel builders were lifted up to a shrine on the wall directly above the giant tunnel boring machine. They gently placed a wooden statue of St. Barbara into the shrine.

Applause erupted from the 250 guests below —tunnel build-ers, scientists, politicians, and nearby residents. Hamburg’s and Schleswig-Holstein’s state ministers for science, Herlind Gundelach and Cordelia Andreßen, took scissors from a red cushion and cut the ribbons to inaugurate the project. The breaking of champagne bottles against the wall of the construc-tion pit and the boring machine christened the newest construc-tion phase of the European XFEL, a new X-ray free-electron laser in Hamburg, Germany.

It was the second time the XFEL’s tunnel builders had called upon St. Barbara, patron of miners and others who work with explosives, to protect them from the dangers of their work. Miners in many countries pay homage to St. Barbara; Germany has a particularly strong tradition that plays an important role for miners and tunnel builders.

Before two boring machines broke ground to carve the 5.8-kilometer tunnel system between the accelerator labo-ratory DESY and the town of Schenefeld, celebrations hon-ored this decades-old custom. A June 2010 ceremony chris-tened the first, 71-meter-long machine, whose cutter head measures 6.17 meters in diam-eter. Its smaller counterpart, with a 5.48-meter cutter head, was christened in December and powered up in early January 2011.

Gundelach and Andreßen,

the state ministers for science, took on the role of patronesses for the tunnels excavated by the two machines. Workers regard patronesses as the earthly rep-resentatives of St. Barbara during the construction period, and name the tunnels after them. The patronesses agree to watch over the tunnel builders and oversee celebrations such as the festival of St. Barbara.

St. Barbara willing, the European XFEL project expects to finish construction and begin research operation in 2015. It will provide extremely intense X-ray flashes to help map atomic details of viruses and cell composition and film chemical reactions, an ability that not too many decades ago would have been considered miraculous. Ilka Flegel

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A saint goes underground at DESY; foreigner physicists get family treatment during

Japanese quake; astronomy takes particle physics on a field trip; ALICE

squeezes in; who needs James Bond when you have neutrinos?; letters; correction

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Disaster brings physics family closerA day after the devastating March 11 earthquake and tsu-nami in Japan, with strong aftershocks still testing surviving buildings, Japanese residents and physicists were offering beds, food, and rides to stranded foreign physicists.

This hospitality in the face of what has been called Japan’s worst disaster since World War II was a lifeline for the 30 mostly American and European foreigners at the Japan Proton Accelerator Research Complex, J-PARC.

“The Japanese are the people who helped the foreigners, not the other way around,” said Stony Brook University physicist Chang Kee Jung, international co-spokesman for the T2K experiment in Japan.

While a 10-foot tsunami caused no damage to the labo-ratory, the magnitude-9 quake took out electricity, water, net-work phone lines, and part of the dormitory housing. Residents of Tokai, facing a water short-age and damaged buildings and roads, shared what meals they had with the physicists, and offered them shelter in a com-munity center.

Two days later, their Japanese colleagues from KEK, the High Energy Accelerator Research Organization in Tsukuba, were making their way on side roads to pick up the foreigners for evacuation to KEK at Tsukuba, and eventually to Narita Airport. The approximately 59-mile drive took seven hours because the quake had made main roads impassable.

Japanese researchers at the KamLAND neutrino experi-ment at Kamioka made a similar journey to the hard-hit coastal

town of Sendai to take food and water to colleagues at Tohoku University there, said Stuart Freedman, co-spokes-man for KamLAND.

Jung, an American physicist who has done research in Japan for 20 years, followed the prog-ress of the aid and evacuation of the foreigners from New York, receiving updates via cell phones and eventually a single Kindle electronic-book reader, which draws less power, until the last battery ran out. Like other physicists across the globe, he wished the best for his Japanese colleagues and their families as their stories slowly emerged through tidbits on social media and newscasts.

Jung said he wasn’t surprised at all by the selfless behavior of the Japanese, or by this dem-onstration that the global particle physics community is, indeed, a family.

“They were just doing what comes naturally,” he said.

To help Japan make a rapid recovery, US researchers continue looking for ways to combine efforts with colleagues in Japan who face personal hardships, repairs to their exper-iments, and power shortages, potentially for a long time to come.Tona Kunz

Physics in a cornfield On a cool September evening in a cornfield south of Chicago, dozens of telescopes turned sky- ward for one of the largest star parties in the Midwest. At the center, Fermilab astrophysicist Dan Hooper was describing something no telescope can see.

As keynote speaker for “Astrofest 2010: The Link between Particle Physics and Astronomy,” Hooper explained physicists’ pursuit of the invisible dark matter and dark energy that make up most of the universe.

“If we want to understand the universe at the largest scales, we have to understand the laws of physics at the smallest scales,” Hooper said. “We can

tell by looking at galaxies that the part of the universe made of atoms is only a very small fraction of it. Dark matter and dark energy make up 95 percent of the universe, but we still don’t know what they are.”

Astronomers and particle physicists have joined forces to explore the universe’s dark side. “In recent decades, these two seemingly different fields have become very interconnected,” Hooper says.

The connection spurred the Chicago Astronomical Society to focus for the first time on par-ticle physics during its yearly Astrofest star party. Founded in 1862, the society is the oldest amateur astronomy group in the US. Its members, from all walks of life, meet annually for two days and two nights of what organizer Jim Cuca calls “astronomy overload.”

“At your typical star party, everybody just sits around and waits for it to get dark,” Cuca says. “Astrofest is unique in fill-ing the day with speakers. Most of us don’t understand things like general relativity, so we need professionals at our meetings to clear up misconceptions.”

Between talks and tele-scope-peering time, participants showed off their newest tele-scopes and cameras, shared tips of the trade and quizzed Hooper on his dark matter research.

“There were a lot of great questions and interaction,” Hooper says. “People who do amateur astronomy are by nature inquisitive about how the universe works, and they take it very seriously.”Sara Reardon

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ALICE’s tight squeeze Anyone who has ever tried to move a big piece of furniture through a small door knows a few centimeters can mean the difference between success and failure.

For Detlef Swoboda, the margin of error felt very small indeed: He had to move 30 pieces of a mammoth, multimil-lion-dollar dipole magnet 60 feet into the air, through a narrow passageway and 60 feet back down, where it would be reas-sembled and used in the ALICE experiment.

How big were those pieces? They weighed at least 33 tons each.

How much clearance did he have? No more than 2 or 3 centimeters.

The move wasn’t easy, but it saved ALICE—one of four major experiments at the Large Hadron Collider in Geneva—both time and money.

The big savings came from installing the ALICE detector in a cavern previously occupied by another experiment, called L3, and reusing L3’s mon-strous solenoid magnet. The L3

magnet is bright red, four stories tall and rooted right in the middle of the cavern. The exper-imenters didn’t want to risk damage—plus added time and expense—by taking it apart and moving it aside. So to fit every-thing in, they’d have to move all the components of their enormous new detector magnet, the muon dipole, up over the top of the red monster and down the other side.

Swoboda is the project leader for the new dipole mag-net. His team lowered the 30 chunks of the dipole 165 feet down the entrance shaft to the cavern, assembled and tested the entire magnet, took it apart again and used an overhead crane to move the pieces, a few centimeters per minute, over the big L3 solenoid. The dipole’s two 36-ton coils made it with 3 centimeters to spare. The whole process took several months.

When asked if he ever thought the task might simply be too difficult, Swoboda gives a laugh. “I’m a designer and a builder of magnets,” he says. “It was just my job.”Calla Cofield

The James Bond of detectorsWho needs secret agents when neutrinos are happy to spill the secrets of rogue nuclear activity?

In a recent paper, Thierry Lasserre and colleagues at the French Alternative Energies and Atomic Energy Commission explain how to spot illegal nuclear activity by putting a neu-trino detector in a supertanker and sinking it off the shore of a nation suspected of clandes-tine activity.

The detector, the Secret Neutrino Interactions Finder (SNIF), could track neutrinos and antineutrinos emitted by illegal nuclear reactors, aiding groups such as the UN’s International Atomic Energy Agency, the physicists contend. The IAEA tracks which governments have access to nuclear technol-ogy and how they use it.

Detecting neutrinos from nuclear reactions is nothing new; many neutrino experiments already rely on nuclear power plants as steady sources of neutrinos to feed their detectors.

“We wanted to set the bounds of what such a device could do to detect undeclared activity,” Lasserre says.

The November paper in Physical Review C provides a global map of nuclear reactors and estimates the number of antineutrinos each should emit. Any extra neutrinos in the area might indicate a rogue reactor.

It would take six months for the type of SNIF detector described in the paper to find a medium-sized, 300-megawatt nuclear reactor 186 miles away, Lasserre adds.

For the moment, no one has plans to build such a detector, which would have to withstand the extreme pressure a mile below the ocean’s surface. Plus, the estimated $4 million price tag would buy a lot of shaken martinis.Sara Reardon

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letters

correction

Right- or left-hand rule?A story in the February 2011 issue talks about how Andreas Moll “walked the crowd through the right-hand rule” during a particle physics slam, but the picture on page 7 shows everybody using their left hand. What’s the deal?Jonathan Link, Virginia Polytechnic Institute and State University

The editors respond: You’re not the only astute reader who noticed this! We contacted Moll, who said he was in fact demonstrating the right-hand rule using his left hand. The purpose of the rule is to show which way charged particles—in this case, electrons forming an electrical current—flow in a magnetic field. Either hand works. When you use your right hand, your thumb points in the direction the electrical current is coming from; when you use your left, it points in the direction the current is flowing.

Thumbs up for cosmic gall I was just paging through my newly arrived issue of symmetry, and would be amiss if I didn’t tell you how much I enjoyed “deconstruction: cosmic gall.” Very clever, and educational.

PS I will indeed stop by The Parker Pie Co. should I ever be in the area!Kathleen Laufenberg, National High Magnetic Field Laboratory

Mirrors for giants I noted with interest the photo on page 20 of the February 2011 issue of the blank for the 27.5-foot-diameter primary mirror of the Large Synoptic Survey Telescope. I remember as a boy in the late ‘30s seeing the newspaper articles and photos of the 200-inch mirror blank for the Hale Telescope being transported from the Corning Glass works in Corning, New York to Palomar Observatory in California, and a couple of years ago seeing the first experimental blank at the Corning Glass Museum. How might I obtain more info on these giants?

I enjoy reading symmetry very much, even though a long-retired slide rule, straight edge and triangle mechanical engineer.Nils I. Larson , Phoenix, Arizona

The editors respond: The Palomar Observatory website should bring back pleasant memories; you’ll find information on the history of the Hale Telescope and photos of its construction (which took 21 years!) at www.astro.caltech.edu/palomar/

Free resources for studentsI would like to thank and encourage your publication for doing a great job of furthering science and math education.

When I was in college I earned money in work-study through tutoring both college and high school students, and nothing turned them away from the sciences and math faster than trying to do research online and being asked to pay anywhere from $15 to $50 for an article, or $30 to $1500 for a sub-scription, to be able to read research papers. The ironic thing is these same journals complain about students not going into the sciences.

Keep up the good work. I give your URL to any student who is interested.P. Randolph Sturm, Reno, Nevada

Wandering observatoriesIn an article about the Large Synoptic Survey Telescope in our February 2011 issue, a photo on page 18 incorrectly identifies the location of the LSST with respect to two existing observatories on Cerro Pachón in Chile. The Gemini South and SOAR obser-vatories are correctly labeled here. The LSST site is not visible because it’s behind the observer. Also, a photo on page 20 shows the blank for the LSST’s 27.5-foot primary mirror; it will not be used for the 16.5-foot tertiary mirror, as stated in the caption.

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Highlights from our blog

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Fermilab’s proposed Project X could offer energy applicationsApril 12, 2011

A proposed high-intensity pro-ton accelerator complex at Fermilab could demonstrate technologies required to burn up dangerous radioactive elements in nuclear waste, greatly reduc-ing its half-life and the time needed to store it in isolation.

Fermilab’s data peak causes excitementApril 7, 2011

The physics world is buzzing at the news that a peak in data from the CDF experiment at Fermilab’s Tevatron collider could be explained by a new, unknown particle that is not pre-dicted by the Standard Model. The particle, if it exists, would not be the long-sought Higgs boson, but could be a com-pletely new type of force or interaction. The CDF scientists are examining more data to see if the peak holds up or vanishes.

Next-generation particle accelerator starts up at Daresbury LaboratoryApril 6, 2011

EMMA is a proof-of-principle prototype for a brand-new type of particle accelerator. It not only uses technology that is simpler and less expensive than today’s equivalent accel-erators, but also promises applications such as treating cancer and powering safer nuclear reactors that produce less hazardous waste.

MEG experiment may give boost to supersymmetryApril 4, 2011

Scientists at the Large Hadron Collider came up empty-handed in their first searches for evidence of the theory of supersymmetry. But preliminary results from MEG, an experi-ment initiated by the University of Tokyo, give supersymmetry fans a glimmer of hope.

Rare particle decayshint at new physicsMarch 30, 2011

Physicists at the LHCb exper-iment at the Large Hadron Collider recently reported the first observations of a new way that particles called B mesons decay into other particles. Studying this particular decay could provide clues as to why the universe is made up of matter rather than antimatter.

The Daya Bay Neutrino Experiment: on track to completionMarch 29, 2011

The Daya Bay Reactor Neutrino Experiment brings Chinese and American scientists together

with colleagues from Russia, Taiwan, and the Czech Republic to investigate the phenomenon of neutrino oscillation. How much do different kinds of neu-trinos weigh? And which kind is the heaviest? A photographic tour of the experimental site shows how the researchers hope to trap enough neutrinos to answer their questions.

Buzz Aldrin visits the LHCMarch 25, 2011

One of the few people in history to walk on the moon recently became one of the few people in the world to push a big red button in the control center at the Large Hadron Collider. During a visit to CERN, American astronaut Buzz Aldrin was allowed to dump the beam.

Interesting effect at the Tevatron hints at new physicsMarch 18, 2011

Scientists at the Large Hadron Collider may be on the verge of discovering a new particle, according to mounting evidence from experiments at Fermilab’s Tevatron. The evidence emerged from studies of the production of the top quark. The CDF and DZero experiments see signs of an asymmetry that standard theory cannot explain.

Read the full text of these stories and more at www.symmetrymagazine.org/blog/may2011

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Speedy single top sighting at the LHCMarch 15, 2011

It took Fermilab scientists at the Tevatron more than 13 years to observe a single top quark after discovering it paired with its antiparticle in 1995. The CMS experiment at the Large Hadron Collider has accomplished the same feat after examining roughly the same amount of col-lision data as the Tevatron exper-iments collect in three days.

Tevatron experiments report new Higgs search resultsMarch 14, 2011

The CDF and DZero experi-ments at Fermilab have reached new ground in their quest to find the Higgs boson, a key member of the particle zoo known as the Standard Model. For the first time, each experiment by itself excludes regions of the expected Higgs mass range, as more sophisticated data analysis techniques and more data from the Tevatron particle collider have increased their sensitivity to the Higgs boson.

LHC revs up for a year of new physicsFebruary 25, 2011

CERN scientists learned to drive the Large Hadron Collider in

2010. This year, they’re ready to take it on the highway. Scientists expect to collect about 100 times as much data in 2011 as they did in 2010, said physicist Gustaaf Broijmans of the ATLAS experiment during a webcast for the National Science Foundation. This will give them their first real chance at making new discoveries, he said.

Chocolat à la particle acceleratorFebruary 14, 2011

If your sweetheart gave you chocolate this Valentine’s Day, you might have a particle accel-erator to thank for its scrump-tious taste. Using the European Synchrotron Radiation Facility, ESRF, in Grenoble, France, sci-entists from the University of Amsterdam got a close-up view of the molecular structure of chocolate. Their research allowed candy manufacturers to develop new techniques that could avoid the dreaded “fat bloom”—the white powder that can form on the outside of chocolate.

LHCb event display —decoded!February 7, 2011

One of the four major experi-ments built around the collision points of CERN’s Large Hadron Collider, LHCb studies B particles, which are com-posed of bottom quarks. This walk through an event display showing the first B particle detected by LHCb shows how the collision data is analyzed.

Particle physicist lends skills to planet huntFebruary 4, 2011

You don’t normally think of high-energy physicists working with NASA to find planets that humans could live on. Jason Steffen, an astrophysicist at Fermilab, is a long-time member of NASA’s Kepler Mission and its only practicing particle physicist.

Giant virus, tiny protein crystals show X-ray laser’s potentialFebruary 2, 2011

SLAC National Accelerator Laboratory’s iconic linear accelerator—nearly 2 miles long, and for many years the longest building in the world—no longer speeds electrons and positrons toward high-energy collisions. But it’s still going strong: One-third of the linac now feeds electrons into the Linac Coherent Light Source, which opened in 2009 as the world’s most powerful X-ray free- electron laser. The first biological studies there demonstrate the LCLS’s potential for groundbreaking research.

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Light sources are the ultimate killer apps for particle

physics technology. Their brilliant X-rays illuminate

every aspect of the material world, from the inner work-

ings of cells to the intricate dance of the electrons that

create chemical bonds. As these all-purpose scientific

tools evolve, the payoffs include better batteries,

greener energy, new high-performance materials, more

effective drug treatments, and a deeper understanding

of nature.

By Lori Ann

White

SHEDDING

LIGHT

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In 1971, physicist Burton Richter of Stanford Linear Accelerator Center was building a new type of particle collider called a storage ring. The lab’s two-mile-long linear accelerator—housed in what was then the longest building in the world—would shoot electrons and their antimatter twins, called positrons, into the 80-meter-diameter Stanford Positron Electron Accelerating Ring, and SPEAR would set the beams of particles on a collision course. Richter and his colleagues stood by to examine the debris to see what discoveries came out.

Physicists were already familiar with one product of accelerating particles in a circle at close to the speed of light: synchrotron radiation. To high-energy physicists, synchrotron energy was an annoyance, an unwanted demonstration of the laws of physics—in this case, a law that says charged particles radiate energy when accelerated. Synchrotron radiation would rob electrons and positrons in the SPEAR ring of energy that would better serve science by going into the creation of new particles and the illumination of new physics.

Two Stanford faculty members, condensed-matter physicist Sebastian Doniach and electrical engineer William Spicer, had a different vision. They saw in the SPEAR storage ring a new and better way to satisfy an already huge demand for X-rays. They saw a source of high-energy electromagnetic waves whose short wavelengths and highly penetrating nature could illuminate materials on a scale small enough to show atomic structures and reveal elec-tronic properties.

Doniach and Spicer approached Richter even before SPEAR was finished.

“They said that they would revolutionize con-densed-matter physics if only I would let the X-ray beam out of the storage ring. That was their pitch,” Richter recalls.

After a quick, informal inquiry to see if the two professors were “blowing smoke,” as he puts it—and obtaining assurances that modifying the ring would not endanger its high-energy physics mis-sion—Richter said, “Let’s do it.”

The SPEAR construction team removed a section of the ring and modified it, adding a beam port to “let the X-rays out.” And Richter did Doniach and Spicer another favor: “I bought them a Sears garden shed to use for experiments.”

The Stanford Synchrotron Radiation Project was under way.

As promised, the stronger, more intense X-rays streaming into the garden shed began making their mark on condensed-matter research and struc-tural biology. Stunningly clear data soon proved the value of synchrotron radiation for investigating the chemical compositions and electronic struc-tures of materials, while the first images of protein structures using such strong X-rays soon followed. Both breakthroughs came as Richter continued to smash together electrons and positrons; the X-ray experiments may have been parasitic on the main program, but the parasites did not disturb their host.

In 1974, Richter and his team discovered the J/psi particle, for which he shared the 1976 Nobel Prize in Physics.

Today, more than 70 light sources are in oper-ation or under construction around the world, including the descendent of that original project, the Stanford Synchrotron Radiation Lightsource or SSRL.

No longer an afterthought, dedicated light sources are critical research tools for everything from dev-eloping better batteries to finding the causes of disease. They contribute to the development of new medicines. They delve into the structures of pro-teins, the secrets of photosynthesis, the behavior of catalysts. Developing high-performance materials, investigating pollution—any time a researcher wants to spy on a process or unravel a structure, if it’s on a molecular—or now atomic—scale, a light source is the tool of choice.

As Richter points out, “Doniach and Spicer were simply too modest when they said they were going to revolutionize condensed-matter physics. They rev-olutionized more than that. Having a million times more intense X-rays gave you capabilities that nobody ever dreamed of being able to exploit.”

Some early experiments at the Stanford Synchrotron Radiation Project took place in a Sears garden shed mounted on the concrete roof of the SPEAR particle storage ring. Ian Munro (third from right, wearing a tie), who was visiting that year from the NINA synchrotron in England, was the key scientist in the development of this experimental station. He provided haggis and drinks to celebrate first light. On Munro’s right are Ben Salzburg, Axel Golde, Sebastian Doniach (first director of SSRP) and George Brown. Photo: SLAC Photo Archives

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Illuminating proteinsThose million-times-more-intense X-rays have trans-formed the study of structural biology, enabling scientists to get the first good look at the intricate cellular machines that build the structures of our bodies and generate the energy that powers us. True, researchers had deciphered some protein struc-tures as far back as the late 1950s—long before the widespread use of light sources. However, by 1973, two years after being established and just as SPEAR was coming on line, the Protein Data Bank held just nine structures. Today the Protein Data Bank, a key resource for structural biologists the world over, holds the structures of more than 72,000 proteins.

The revolution did not happen overnight. At first, the primitive state of imaging technology made high-resolution results very hard to get. The protein crystals themselves were the biggest stumbling block.

As Bob Sweet, a beamline scientist at Brookhaven National Laboratory’s National Synchrotron Light Source, puts it: “You have to understand that protein crystals are the texture of firm Jell-O and very moist. They don’t do very well in an X-ray beam.”

Two breakthroughs—freezing the crystals to retard radiation damage, and the development of better detectors using CCD chips—transformed the use of synchrotron light sources, according to Thomas Steitz of Yale University, who shared the 2009 Nobel Prize in Chemistry for unraveling the structure of the ribosome, the cellular factory that builds proteins from genetic instructions brought by messenger RNA.

“It would have been impossible to have solved the ribosome without a synchrotron—period,” Steitz says. “In my opinion it’s a good thing there are light sources scattered everywhere.”

Discovering drugs Academic crystallographers such as Steitz generally focus on determining the structures of biologically important proteins. Once those structures are unrav-eled, crystallographers from pharmaceutical compa-nies home in on receptor sites on the proteins where disease-causing agents can latch on and wreak havoc. That’s the best place to ambush and disable them.

The techniques for studying these receptors are simpler to execute and faster to complete than determining the structure of an entire protein from scratch. But finding the right drug can still take years. Continually competing for access to beamlines at national facilities just won’t work for pharmaceutical companies—not if they want to get anything accom-plished—yet light sources are generally national facilities for a reason. They’re big, complicated, and full of sophisticated machinery requiring highly specialized knowledge to maintain and operate—in

other words, expensive. Very expensive.Thus was born the Industrial Macromolecular

Crystallography Association, or IMCA, a consortium of pharmaceutical companies that approached Argonne National Laboratory during the construction of the Advanced Photon Source. IMCA members would provide the money to build, equip, staff, and run beamlines; Argonne would provide the X-rays. The result is Sector 17 at the APS, two specialized beamlines dedicated to the fast turnaround of candi-date substances for drugs.

“It’s rather remarkable that all the companies man-age to cooperate,” says Lisa Keefe, director of the IMCA Collaborative Access Team program at the APS. “They are all competitors.” One reason the collaboration works: their work remains proprietary. Membership varies, but currently consists of Abbott, Bristol-Myers Squibb, Merck, Novartis and Pfizer, with subscription programs available to companies that are not IMCA members. As part of the deal with Argonne and the Department of Energy, the beam-lines are also open to general users 25 percent of the time, with “general” referring to anyone who comes up with a good proposal. In practical terms, this means academic research groups.

Time is money to these companies, and their money has bought them time. According to Keefe, the beamlines are focused on very-high-throughput screening and data collection. With the state-of-the-art instrumentation at beamline 17-ID, researchers can collect a data set every three to five minutes.

One of the first members of IMCA, pharmaceutical giant Abbott Laboratories, used the APS to study HIV, the virus that causes AIDS. That research directly contributed to the development of Kaletra, a highly

Lisa Keefe at one of the two Advanced Photon Source beam-lines she oversees at Argonne National Lab. The Industrial Macromolecular Crystallography Association, a consortium of major pharmaceutical companies, designed, built and staffed these beamlines. IMCA member companies do research there on potential drug treatments.Photo courtesy of L. Keefe, Industrial Macromolecular Crystallography Association

Biological, Life, and Medical Sciences 38%

Chemistry 18%

Materials Sciences 14%

Physics 10%

Enviromental Sciences 7%

Engineering 6%

Earth Sciences 3%

Polymers 2%

Optics 1%

Instrumentation or Technique Development 1%

Research at the SSRL

Light source basics: the Stanford Synchrotron Radiation Lightsource

Free electron laser

Electrons slalom through the paired magnets of an undulator in a free-electron laser. The back-and-forth motion causes them to emit synchrotron radiation. Unlike the synchrotron light emitted by particles going around a storage ring, the radiation from FELs is coherent, with the crests and the troughs of the light waves lined up; coherence gives it much more intensity. Image: Sandbox Studio

Beam of electrons Light

Bristling with beamlines

At SLAC’s SSRL and other synchrotron light sources, electrons speeding around a ring emit intense light, usually in the form of X-rays. The light streams out of the ring into beamlines equipped with specialized instruments for conducting a wide variety of

experiments. This diagram shows the types of research taking place at each SSRL beamline. The dotted lines show planned future beamlines.

Techniques

X-Ray Absorption SpectroscopyReveals the physical, chemical, or elec-tronic structure of a sample. XAS is used in molecular and condensed-matter physics, materials science and engineer-ing, chemistry, earth science, and biology.

ImagingMaps the elemental composition of a sample. Often used to help target more focused probes. Imaging techniques are used in engineering, chemistry, biol-ogy, and earth, environmental, and material sciences.

Scattering/DiffractionScatters X-rays off a sample to probe its structural properties. When the sample has a regular structure—for instance, when it’s crystallized—this process is known as diffraction. Scattering and diffraction are used in molecular and condensed-matter physics, materials science and engineering, chemistry, earth science, and biology.

Macromolecular CrystallographyUses diffraction (see above) to determine the structures and functions of large biological molecules such as proteins, viruses and nucleic acids (RNA and DNA). Macromolecular crystallogra-phy is an important tool for biology, physi-ology, medicine, and drug development.

OtherThis beamline produces visible light for testing and commissioning new equipment.

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effective protease inhibitor that stops the HIV virus from replicating. GlaxoSmithKline relied on research conducted at the APS to create Votrient, a treatment for kidney cancer, and Merck developed Januvia, a treatment for diabetes.

Basic research at light sources has also given rise to start-up companies aimed at turning discov-eries into effective treatments. Steitz co-founded Rib-X Pharmaceuticals, a company that develops more effective antibiotics based on the structural information about the ribosome he gathered at light sources. A Rib-X antibiotic that has made it through phase II clinical trials is designed to combat methicillin-resistant Staphylococcus aureus, or MRSA, an antibiotic-resistant bacterium that kills thousands annually.

In California, Stanford’s Roger Kornberg, who won a Nobel Prize for determining the structure of a key enzyme involved in translating DNA’s genetic instruc-tions into proteins, founded a company called Cocrystal Discovery to find drugs that block this process in RNA viruses like the ones that cause influenza and hepatitis.

Cocrystal is carrying out studies at a number of DOE light sources, including Argonne’s APS and the two facilities where Kornberg performed his prize-winning research—SLAC’s SSRL and the Advanced Light Source at Lawrence Berkeley National Laboratory.

“I believe the whole future of drug development lies in synchrotrons,” says Kornberg, who heads a research lab at Stanford’s School of Medicine.

Light sources vs. diseaseLisa Miller uses Brookhaven’s NSLS, the first facility built expressly for research using synchro-tron radiation, to study diseases themselves. Two favorite targets are Alzheimer’s disease and amyotrophic lateral sclerosis, also known as Lou Gehrig’s disease.

Miller and her research group have made good progress in understanding the cause of Alzheimer’s using synchrotron light sources, although at this point in her research, “progress” means the ability to ask more pointed questions.

They use two different types of synchrotron-based microscopes to examine the Alzheimer’s-afflicted brain, Miller explains. Synchrotron infrared light reveals organic materials like proteins and lipids. With syn-chrotron X-rays, Miller can identify traces of metals like copper, iron, and zinc.

Miller uses infrared microscopy to study the struc-ture of amyloid plaques, the tell-tale clumps of misfolded protein that mark the brains of Alzheimer’s victims. “For some reason, these plaques are toxic and kill brain cells,” she explains. “The brain of an

Alzheimer’s sufferer can shrink to 60 to 70 percent of its original size.”

Using X-ray microscopy, Miller has discovered that human plaques are loaded with metal ions, espe-cially copper and zinc. But interestingly, mice that are genetically engineered to develop Alzheimer’s plaques do not have metal in their plaques—and their brain cells do not die.

“Is it the metal that causes plaques to be toxic? And how does the metal get there in the first place?” she asks. “You don’t have free copper just floating around in your body. That would be toxic.”

To answer her questions, Miller wants to get a closer look at the sticky plaques and trapped ions. She’s eagerly awaiting the National Synchrotron Light Source II, which will generate X-rays more than 10,000 times brighter than those of its predecessor. “It will have a resolution of tens of nanometers,” she says. “We’ll be able to see individual neurons—or even individual mitochondria within the neurons.” She

Top: A series of images from research at the National Synchrotron Light Source. 1) Amyloid plaques associated with Alzheimer’s disease in human brain tissue, fluorescing in green; 2) zinc and 3) copper ions in the same tissue sample; and 4) an overlay of the previous three images reveals that the plaques contain high levels of the two metals. Bottom, from left: Lisa Miller, Andreana Leskovjan, and Tony Lanzirotti at one of the NSLS beamlines at Brookhaven National Lab where they conducted their Alzheimer’s research. Images and photo courtesy of L. Miller, Brookhaven National Laboratory

1) visible fluorescence

3) copper

2) zinc

4) overlay

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wants to examine what’s there even before the plaques form.

In the meantime, she’ll continue to put the NSLS to good use for as long as she can.

“My fear is that the bad budget situation will cause the NSLS to turn off before NSLS-II turns on,” she says. If that happens, Lisa Miller will truly find herself in the dark about Alzheimer’s disease.

Building better batteriesAt Berkeley Lab’s ALS, scientist Wanli Yang and his colleagues are developing better electrode materials for lithium-ion rechargeable batteries. Currently these batteries are the most popular—and most promising—rechargeable battery technology, but there’s definitely room for improvement.

For example, graphite, a form of carbon commonly used in lithium-ion battery anodes, is actually not the most efficient material for energy storage. Other sub-stances, such as silicon, have a much higher energy capacity—they can hold more lithium ions when a bat-tery is charged.

But researchers have already learned that replacing the graphite with silicon leads to other problems. When lithium ions flow into a silicon anode during charging, the volume of the anode expands almost three-fold. When the battery is discharged, the ions flow out of the anode and the silicon is left adrift, leading to broken mechanical and electrical connections that ruin the battery.

Collaborating with material chemists and theore-ticians, Yang’s group has been using the X-rays of the ALS beamline to study versatile polymer materials that could “glue” the molecules of the silicon anode together while maintaining good electrical conductivity, thereby enabling the best of both worlds—high energy capacity and the ability to withstand numer-ous recharges.

A more fundamental goal is to reveal crucial electronic structures that actually define battery performance, thus providing a basis for the devel-opment of even higher-performance materials for use in future batteries.

Yang reports progress on this front, as well. The collaboration has pinned down a particular electronic state of the polymer, what Yang calls “a very special energy for electrons to stay with,” that’s key to main-taining efficient battery operations. This electronic state can be measured directly by soft X-ray spec-troscopy, and, says Yang, such synchrotron-based direct probes turn out to be a very powerful method for studying other battery materials, as well.

“Synchrotron-based X-ray spectroscopy is the only technique that can tell us all the detailed information we need,” says Yang. “It’s chemically sensitive, sen-sitive to the orbitals of the electrons. By using soft X-ray spectroscopy, we can see where the electrons are and where they go.”

Can we do what plants do?If only we were like plants. Plants don’t have an energy crisis and won’t for another five billion years. That’s because—as we learned in school—plants pull all the energy they need from the sun, convert-ing light energy to chemical energy by turning carbon dioxide and water into sugars and releasing oxygen as a waste product.

Plants have it made.But what if we could do the same, in a sense—

convert sunlight to chemical energy of a form more suited to our industrialized society, such as biofuel?

We’d have it made.That’s the motivation for the Joint Center for

Artificial Photosynthesis (JCAP), a collaborative effort among several California universities and national laboratories that’s funded by the US Department of Energy.

Jinghua Guo is a scientist at the ALS, at Lawrence Berkeley National Lab, which—along with SLAC and the University of California at Berkeley—constitutes the northern California JCAP site. According to Guo, “The idea behind JCAP is to discover a system that mimics nature—but first you have to understand what happens in nature.”

Guo and other JCAP scientists use soft X-rays from the ALS to watch nature’s chemistry happen. Generally that means watching electrons move around, or even arranging them himself and then watching what happens. “You can tune soft X-rays so precisely that you can put an electron where you want,” he said.

One system Guo is investigating with other JCAP scientists consists of a cluster of titanium, manganese, and cobalt atoms. Put the cluster in solution, says

Berkeley Lab staff scientist Jinghua Guo uses the lab’s Advanced Light Source to study the electronic structure of a catalyst designed to promote a chemical reaction involved in artificial photosynthesis. In situ studies like these, which take place in realistic operating environments, play an impor-tant part in designing new materials with improved qualities.Photo: R. Kaltschmidt, Lawrence Berkeley National Laboratory

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Guo, and it will effectively absorb sunlight and release oxygen from water. They’re trying to unravel the details of that reaction.

Experiments like these, which look at how mate-rials function in realistic operating environments, are a tricky but important part of an approach known as materials by design, said Zhi-Xun Shen, SLAC’s chief scientist and head of the Stanford Institute for Materials & Energy Science.

It starts with using theory and computer simula-tions to design a new material—whether a catalyst, a battery component, or a novel superconductor that carries electricity with 100 percent efficiency. Scientists go into the lab and make samples of the material, then use X-rays from a light source to determine its struc-ture and chemical composition and watch it perform under realistic conditions. Catalysts go through more rounds of testing to see how active and selective they are in promoting specific chemical reactions.

SLAC’s Anders Nilsson, who is deputy director of SUNCAT, the Center for Sustainable Energy through Catalysis, has a particular interest in sur-faces; that’s where catalysts do their work of helping chemical reactions happen. Recently he led a research team that used the lab’s SSRL to get a good look at a platinum catalyst in the act. They created a sample of platinum one layer thick, hit it with a wave-length of X-ray light that was tuned to interact with the platinum and only the platinum, and captured what happened with a recently developed and highly sensitive type of X-ray spectroscopy called high-energy resolution fluorescence detection.

Capturing what happens to a sample in a realistic environment enables researchers to connect theory to reality, Nilsson says, adding, “X-rays have a really great potential for illuminating surface chemistry, which can give us insights into the development of new materials.”

The future: bright and brighterThe Stanford Linear Accelerator Center is now SLAC National Accelerator Laboratory. SPEAR3 is still going strong, running 24 hours a day nine months of the year, serving 1400 users annually at more than two dozen experimental stations.

As for the famous 2-mile-long linac? Fittingly in the era of reuse, recycle, and reduce, the lab has repurposed it to accelerate electrons for the Linac Coherent Light Source. The LCLS is the premier example of the newest generation of light source, the free-electron laser. FELs, with their pulses of X-ray laser light, can see even smaller objects and follow even faster reactions than can regular syn-chrotron radiation sources.

The LCLS, the first of the hard X-ray FELs, is a billion times brighter than the brightest conventional

light source. It packs all its energy into laser pulses of less than 1/10th of one trillionth of a second. These ultrafast pulses promise to take portraits of atoms, not just molecules, and to capture chemistry in the act.

Keith Hodgson is SLAC’s associate laboratory director for photon science and the lab’s chief research officer. He’s been a researcher at the lab since the pioneering days of SSRP. Hodgson points out that the LCLS owes a special debt to high-energy physics. Getting the electrons to lase required exqui-site control of the electron beam—“a 5-micrometer beam over long distances, with high precision,” he notes. Only accelerator physicists trained to meet the exacting needs of particle physics experiments could have done it.

Two papers appearing recently in the journal Nature hint at the LCLS’s capabilities. In one experi-ment, a team of researchers captured single-shot images of an entire uncrystallized Mimivirus, the larg-est known virus. In the second experiment, the same team confirmed the molecular structure of a hard-to-crystallize protein called Photosystem I, an important protein complex involved in photosynthesis, using nano-sized versions of the crystal that are easier to prepare. If it lives up to its initial promise, the technique could cut years off the analysis of some proteins.

Still ahead: molecular movies of chemical pro-cesses that happen too quickly to capture with conventional X-rays.

Forty years ago Sebastian Doniach and William Spicer told Burton Richter they would revolutionize condensed-matter physics if Richter would let the X-rays shine.

The X-rays are shining brighter than ever, and the revolution continues.

Top: An X-ray laser pulse from the Linac Coherent Light Source hits a molecule and scatters light into a detector, forming a diffraction pattern. By combining many diffraction patterns (bottom left), scientists recreate the protein’s 3D structure (bottom right)Images: G. Stewart, SLAC National Accelerator Laboratory

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Illustration: Sandbox S

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L NE: THE INSIDE BUZZ ON A NEW SCIENCE PROJECT

Planning and designing the $900 million Long Baseline Neutrino Experiment takes more than a village. It takes a hive’s worth of scientists, engineers, technicians, accountants, and other specialists of every stripe.

By Amelia Williamson Smith

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Top: Experiment co-spokes-person Bob Svoboda of the University of California, Davis. Bottom: LBNE collaboration members during a meeting at Fermilab.Upper photo: B. Plummer, SLAC

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A single bee colony, that model of industry and organization, may contain upwards of 40,000 bees. Yet so flawlessly choreographed are their inter-actions and so well does each bee knows its business that the whole hive effectively functions as a single organism. While the hundreds of collab-orators in a large scientific project may not see themselves as one big organism, in fact they have much in common with the bees. To achieve sweet success, they must all carry out their particular roles in the project, and they must work together in a highly organized and coordinated fashion.

A look behind the scenes of Fermilab’s Long Baseline Neutrino Experiment reveals a colony of scientists, engineers, and project specialists, from across the United States and around the world, abuzz with the work of creating what they hope will become the world’s most advanced neutrino experiment. Each member of the 300-person team for this $900 million undertaking has a specific set of tasks. An intricate system of organization and communication meshes their efforts together to achieve each stage of the project’s development—from initial approval to construction, oper-ation, and scientific discovery.

BIRTH OF A PROJECTLBNE will measure fundamental properties of neutrinos to probe questions at the heart of 21st-century particle physics. The “Long Baseline” in Long Baseline Neutrino Experiment refers to the distance a beam of neutrinos traverses from its origin to a detector. Fermilab accelerators will generate the world’s most intense neutrino beam and aim it through the earth to underground detectors at the Homestake Mine in Lead, South Dakota, 800 miles away. Another detector on the Fermilab site, known as the near detector, will characterize the beam as it starts its journey.

“We’re trying to determine why neutrinos have masses so much smaller than those of all the other particles, and how their masses stack up—the hierarchy of their masses,” says LBNE co-spokes-person Bob Svoboda of the University of California, Davis, one of two scientists who represent the experi-mental collaboration to the world beyond. “Neutrino mass hierarchy has profound implications for the unification of forces and particles, a critical issue of particle physics. Neutrinos may also help us understand the asymmetry between matter and anti-matter that led to the evolution of the universe that we see today.”

Communication—via computer and smart phone, in person, and by hand-waving—is crucial to a large and far-flung scien-tific project, says LBNE Project Manager Jim Strait of Fermilab (bottom right).Photos: R. Hahn, Fermilab

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Planning for a new-generation neutrino experi-ment began in 2000. A series of studies, simulations, workshops, and reports by neutrino physicists eventually converged on the need for a neutrino experiment with a baseline longer than 600 miles. In May 2008, the ten-year strategic plan of the Particle Physics Project Prioritization Panel, P5, recommended designing an experiment that would send a high-intensity neutrino beam from Fermilab to Homestake Mine.

A core group met at UC-Davis in February 2009 to begin design planning. Less than one year later, the Department of Energy gave LBNE an initial level of approval, called Critical Decision Zero, which established “mission need” for the project and endorsed its scientific value.

Now the LBNE team must work its way through four more of these critical decisions, each one key to further funding. Each level has its own set of criteria developed from years of Office of Science experience in learning to build scientific projects on time and on budget.

INSIDE THE HIVEIn a beehive, every day is a marvel of collaboration and communication. The same holds for the LBNE project, with a few key differences. The bees, for example, all live in one hive, but with project and collaboration members spread around the globe, long-distance communication is a way of life for LBNE.

Phone conferences, online presentations, e-mails, and face-to-face meetings keep everyone connected. LBNE team members are continually popping into each other’s offices to try out ideas. Whiteboards turn black with sketches of facilities and caverns, diagrams of beamline and detector components, physics reach plots, and outlines organizing proj-ect documentation.

Equally humming with daily activity are LBNE’s online workspaces, where project members can upload and share files, fill virtual whiteboards, make milestone lists, create event calendars, assign tasks, schedule and hold meetings, and send more messages.

For Project Manager Jim Strait of Fermilab, there is no such thing as a normal day. Managing a $900 million project involving 300-plus collabo-rators from 58 institutions across the US, India, Italy, Japan, and the United Kingdom brings daily challenges.

Constant interaction keeps both beehives and large projects humming. Yale post-doc Roxanne Guenette, on screen at top left, joins a meeting remotely.

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He joined LBNE shortly after it received DOE’s initial approval in January 2010. “It was as if I were leaping onto a moving train,” Strait says. “My first goal was to orient myself by learning about the neutrino detector technology and establishing every-one’s roles and responsibilities so that we could start defining exactly what the project will be.”

He adds, “In a general sense we know the main project elements. Now we’re trying to figure out which configuration of those elements is best. There’s a long road ahead, but we’re steadily making progress.”

Five sub-teams are developing LBNE’s con-ceptual design. Fermilab manages the project and leads the design for the beamline. Los Alamos National Laboratory leads the development of the near detector, and Fermilab and Brookhaven National Laboratory are each leading the investiga-tion of a potential technology for the far detectors. One of those detector types— either water Cherenkov or liquid argon—will be chosen and installed in the Homestake Mine.

Yale postdoc Roxanne Guenette is on the liquid argon detector team (see “Eminently Noble,” page 25, for details of the technology.) She’s exploring exactly how the massive detector would work and how to search for new physics in the data it would provide. She runs simulations that show what scientists can expect to see in the far detector under different detector configurations. Guenette also works on Fermilab’s MicroBooNE experiment to build and operate a liquid argon detector on a much smaller scale.

“If liquid argon is chosen for the LBNE far detector, it is going to be a really interesting and exciting challenge to develop the new technology on such a large scale, going from the 100-ton scale to tens of kilotons,” Guenette says. “The most rewarding part of working on LBNE is to see all of the science that we can do with such massive detectors. Today’s experiments are finding interesting results, but we really need to know more. LBNE is pushing the science another step forward.”

Brookhaven electrical engineer Tom Russo is coordinating the design of the other far-detector candidate—a water Cherenkov detector as big as a 20-story building.

Russo says he’s been building electronics since he was a teenager. “I’m taking my lifetime of experience and applying it to putting together this giant detector and making it successful,” he says. “We have to get it right the first time, and there are so many things we have to think about.”

One challenge is designing the detector components so that they can pass through a small shaft into the mine for assembly underground, Russo says:

Bottom right: Brookhaven National Laboratory electrical engineer Tom Russo coordi-nates the design of a neutrino detector the size of a 20-story building.Photo courtesy of Brookhaven National Laboratory

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“We have to figure out the most efficient and cost-effective way to get these massive structures underground, something I’ve never had to do before.”

He’s not the only one thinking about cost-effectiveness. The LBNE team is now examining more than 75 cost-cutting proposals to determine how each one would affect the project’s bottom line and physics capabilities. Once they settle on the optimal design for the money, the task will shift to completing reams of documentation, including detailed cost estimates and a timetable that maps out the resources required to meet the proj-ect’s schedule.

E PLURIBUS UNUMEach member of LBNE’s core project support team has a specific role. As project manager, Strait oversees everything and makes sure the project accomplishes what it sets out to do within budget and on schedule. The team includes a project engineer, project scientist, and computing coordi-nator. A risk manager identifies any factor—cost, schedule, technical components, environment, safety, health—that could affect the project, and takes steps to mitigate it. Others manage environmental safety and health, keep on top of finances, oversee work planning and schedules, juggle volumes of paperwork and documentation, and perform the many admin-istrative tasks, from setting up videoconferences to making purchase orders, that keep any enterprise afloat.

“To make progress in such a large project, constant communication and teamwork are crucial, and if those break down, nothing will work,” Svoboda says. He adds that it’s important to keep everyone focused on the goal and establish a sense of mutual trust and respect throughout the project.

A bee couldn’t have said it better: collaborators and project staff must function as a single organization, not just as a group of scientists and engineers with many different interests.

“The key to getting everyone to work together on such a large scale is generating a common understanding of what the project and collaboration are working together toward,” Strait says. “In the end, our job is not to build the most beautiful beam-line or detectors. Our job is to use neutrinos to uncover the secrets of the universe.”

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E M I N E N T LY

BY SARA REARDON

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When it comes to detecting neutrinos or particles

of dark matter, four noble elements—helium, neon,

argon, and xenon—stand out for their standoffishness.

Like the beckoning glow of neon signs in the night, the noble gases hold an irresistible allure for researchers. Shimmering and scin-tillating, these elitists of the periodic table have properties that seem custom-made for scientists on the track of dark matter particles or nearly undetectable neutrinos.

We’re most familiar with these elements in their gaseous, room-temperature forms. Helium fills party balloons and turns voices squeaky when inhaled; neon gas, along with other gases that glow in different colors, fills the glass tubing of neon signs. Lined up along the right edge of the periodic chart, helium, neon, argon, krypton, xenon, and radon are known as noble gases for their standoffish refusal to interact with their proletarian neighbors. Unlike the atoms of most elements, each noble atom keeps to itself, refus-ing to share electrons and form chemical bonds with other atoms.

When noble gases are chilled to liquid form, their inert, arms-length nature becomes a real advantage. Purified and poured into a particle detector, they give off flashes of light when particles pass through them. They also allow the trails of electrons left by charged particles to drift unimpeded toward the electrodes that wait to record them.

“They’re very nice materials for many reasons,” says Stephen Pordes, who works on R&D for noble-liquid detectors at Fermilab. “This technol-ogy is ripe for exploiting, and there are many active programs.” But, Pordes says, many techni-cal challenges remain. His work is cut out for him; harnessing the unique properties of these elements is no easy task.

S MALL-BUT-M I G HTY H E L I U MHelium, the second-lightest element after hydrogen, is already a familiar presence in high-energy physics laboratories. It remains liquid when chilled to almost absolute zero, making it an ideal coolant for superconducting magnets in Fermilab’s Tevatron collider and the giant Large Hadron Collider in Europe, as well as in smaller superconducting magnets used in MRI scanners. At those ultralow temperatures, superconducting wires allow electrical current to flow with no resistance and virtually 100 percent efficiency.

Helium’s lightweight nature is what attracted

Debbie Harris and her colleagues. Their experi-ment at Fermilab, MINERνA, studies how the ghostly particles known as neutrinos act when they encounter elements that are very heavy or very light. Its detector contains a stack of mate-rials—liquid helium, lead, graphite, and steel—that offer a veritable playground of environments where a beam of neutrinos can interact.

“In lead and other heavy elements, the nucleus is made up of lots of protons and neu-trons, and they all interact with each other,” says Harris. “In helium, the nucleus only contains two protons and two neutrons. This allows us to study the interaction between a neutrino and a proton or neutron while there are very few other interactions.”

M U LTI FAC ETE D AR G O N Other researchers bring in the big boys of the noble family. Argon, which makes up 1 percent of the air we breathe, is particularly useful for large-scale experiments. Released as a side product of industrial oxygen purification, argon gas is relatively easy and inexpensive to obtain and has a multitude of applications. Argon lasers have proved useful for electronics manu-facturing and retinal surgery, and the gas’s intrinsic inertness helps insulate double-paned windows and protect wine from oxygen.

Scientists have long employed liquid argon in calorimeters, which measure the energy of particles passing through detectors in experiments such as the Large Hadron Collider’s ATLAS. Because it is so inert, argon does not absorb the electrons liberated by the showers of charged particles created in the calorimeter; instead, it leaves them free to move toward electrodes for detection, drawn by a high-voltage field. The intensity of the showers and the electric charge they liberate indicate the energy of the particles passing through the detector.

In the mid-1970s, physicist Carlo Rubbia was one of the first to conceive a viable neutrino detector using liquid-argon technology. Today, he is the spokesperson for ICARUS, an experiment that contains 600 tons of liquid argon. ICARUS started taking neutrino beam data at Gran Sasso National Laboratory in Italy in 2010.

FR O M BU BBLE S TO BR EAD C R U M BSThe concept behind ICARUS and other liquid-argon-based particle detectors is in some ways similar to that of the bubble chambers used in the early days of particle physics. A neutrino collides with an atom inside the detector and produces charged particles that create tracks as they pass through the detector. In the case of a bubble chamber, the detector contains a liquid held just at the edge of boiling. As the charged particles traverse that liquid, bubbles arise and leave visible, swirling tracks that cameras record on film for analysis.

“Argon is a wonderful material,” says Stephen Pordes, who develops noble-liquid detectors at Fermilab. Photo: Reidar Hahn, Fermilab

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Liquid-argon technology allows researchers to skip the steps of operating cameras and maintaining a liquid at the sweet spot just short of boiling. As the charged particles produced by a neutrino interaction move through an argon-filled tank, they leave a breadcrumb-like trail of electrons behind them, invisible to the naked eye. An electric field pulls this trail across the tank toward a grid of thin wires. When the electron trail reaches the grid it electronically imprints its two-dimensional pattern, similar to a shadow projected onto a wall. The time it takes for each electron breadcrumb to reach the grid provides the third dimension and gives the argon tank its name: a Time Projection Chamber, or TPC.

S CAL I N G U PFermilab’s ArgoNeuT detector uses a liquid-argon TPC to study the properties of neutrinos. During a short run in 2010, ArgoNeuT recorded a large sample of neutrino events, confirming the effectiveness of TPCs for neutrino detection. Now, Fermilab is developing the 100-ton MicroBooNE detector for a new low-energy neu-trino experiment. Fermilab researchers see MicroBooNE as a prototype for even larger and more efficient neutrino detectors in the future.

“MicroBooNE is unique in that in addition to having a set of physics goals we also have a set of development goals,” says Yale physicist Bonnie Fleming, who works on both ArgoNeuT and MicroBooNE. “In every way that we design the detectors, the cryogenics system, the electronic system, the purification system, we’re

trying to design it so that we can best build the next-generation detector.”

In ICARUS, MicroBooNE, and many other noble liquid experiments, one of argon’s flashier qualities provides a second way to detect particle interactions (see graphic, page 28). When an ionizing particle hits an argon atom and excites the atom or knocks off an electron, the atom briefly pairs up with a second argon atom to form Ar2. But the union is too much for the introverted atoms to maintain and it quickly falls apart as the atoms’ electron structure is restored, releas-ing a photon. Rather than absorbing the photon, neighboring argon atoms allow it to twinkle away as visible light, or scintillation, which photomulti-plier tubes convert into electrical signals. While many materials scintillate, argon and xenon are among the brightest.

“Argon is a wonderful material and scintillator,” Pordes says. “In experiments, this light gives an indication that something has happened.”

One of the challenges of the technique is developing electronics sensitive enough to measure the output of a large argon chamber.

“Our collaborators at Brookhaven National Laboratory and Michigan State University are developing electronics that can be mounted inside the liquid-argon tank,” Pordes says. “This advance will improve the sensitivity to the signals deep inside large liquid-argon detectors.”

Another challenge lies in purifying the argon; any residual water or oxygen gobbles up charged particles that are drifting toward the detection equipment. To eliminate these impu-rities, a system continuously filters the liquid argon in the detector. Improving and enlarging purification and detection systems is an intense ongoing R&D effort.

Luckily, liquid-argon detectors are more easily scaled to larger sizes than some other technolo-gies, says Yale’s Dan McKinsey, who works on a dark-matter hunt known as DEAP/CLEAN. “If you want a bigger detector, you buy a bigger bucket of argon,” he says.

Neutrinos left their tracks in liquid argon in this 2009 image from the ArgoNeuT experiment.

Increasing the physics potential of neutrino experiments requires detectors with progressively larger volumes of liquid argon. Image: Sandbox Studio

ArgoNeuTCOMPLETE Measures neutrino-argon cross sections

MicroBooNEPROPOSED Investigates low-energy neutrino interactions

Liquid-argon TPC for LBNER&D IN PROGRESS Measures neutrino oscillations at 1,000+ km

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DAR k MATTE R H U NTLike ArgoNeuT and MicroBooNE, DEAP/CLEAN’s dark-matter detectors exploit noble liquids as a landing pad for rare particles such as WIMPs, the Weakly Interacting Massive Particles that are the current top candidates for dark matter. “We got our tricks from the neutrino business,” McKinsey says.

The DEAP/CLEAN collaboration is currently running two experiments, MicroCLEAN and DEAP-1, at the Sudbury Neutrino Observatory in Ontario, Canada, with two larger ones, MiniCLEAN and DEAP-3600, expected to take off in 2011. A future and even larger proposed experiment, CLEAN, will detect both dark matter and neutrino interactions.

AM BU S H I N G WI M PSDEAP/CLEAN operates on the premise that when it comes to dark matter, two liquids are better than one. After a year or so of running with argon, the researchers pump the argon out of the detector and replace it with liquid neon. “The ratio of WIMP signals in argon versus neon is predicted to be about a factor of four,” McKinsey says. “So if you see a signal in argon, and then this signal drops by a factor of four when you replace the argon with neon, then this is extra evidence that what you are seeing is WIMPs, as opposed to some kind of background, such as gamma rays, from surrounding materials.”

Dark-matter experiments have long been plagued by these background signals, which can look like the signals scientists expect to see from WIMPs (see graphic, above right).

“Backgrounds are tricky, so it’s critical that we have several different targets with different detection materials,” McKinsey says. “To me, that means several different noble liquids. They can be scaled very large and have the highest sensi-tivity for WIMPs by many orders of magnitude.”

Here, the nobles reveal yet another of their useful properties, a scintillation Morse code that allows researchers to discriminate between WIMPs and the background signals that mimic

them. A gamma ray’s passage through argon or neon results in a long flash of light, whereas a passing WIMP would produce a short blip. This difference allows a computer to discard the long flashes and analyze only the potential WIMPs.

FLAS HY XE N O NBlazing in the headlights of a Porsche or illumi-nating the screen of a plasma TV, xenon, “the stranger” in Greek, scintillates with the best of them. With three times as many protons as its cousin argon, xenon’s nucleus presents a larger target for WIMPs to hit. Liquefied, it can pack a dark-matter detection chamber wall to wall with huge nuclei, increasing the chance for physicists to catch one of these rare particles.

There’s a high price for this rare, precious element, which was originally formed during supernova explosions: one ton of xenon costs $1 million. Yet its density and large nuclei allow re-searchers to use less xenon so the apparatus can be smaller. “Up to a few tons, xenon detectors are price competitive,” says Pordes, and dark-matter researchers are making growing use of them.

Dark-matter interactions are even subtler than neutrino interactions, and physicists often spend months looking for a single candidate interaction, says Rick Gaitskell, spokesperson for LUX, the Large Underground Xenon dark-matter experiment. The problem, he says, is that a detector that could pick up more WIMPs would also pick up more false signals from cosmic rays.

Immersed in a tank of water, 2000 feet underground in the former Homestake Mine, the 350-kilogram LUX detector will be well protected from any obscuring cosmic radiation. Unlike argon, xenon has no radioactivity of its own and can even shield itself from external radiation because it is so inert. The data samples that researchers trust most come from the central part of the tank, which is the best shielded.

“If we have a dark-matter signal,” says Gaitskell, “the contrast with background should be enormous. We’ll be probing levels of sensitivity that have never been probed before.”

BA C A B C X

Liquid-argon-based detectors can sense a variety of particles. A: When an ionizing particle ( ) such as a gamma ray travels through argon, it either excites or knocks electrons off argon atoms ( ) to create Ar* and Ar+ ( ) along its path. B: This leads to the forma-tion of short-lived Ar2 molecules ( ). C: As the argon atoms restore their electronic structure and return to single atoms, they emit photons, causing the liquid to scintillate. Ultrasensitive photosensors can detect this light, even when it comes from a single ionizing particle.

WIMP particles don’t interact with an atom’s electrons. They still can create a scintillation signal. X: Theory predicts that a WIMP ( ) occasionally interacts with the nucleus of an argon atom ( ). This propels the argon atom through the liquid, like a like a billiard ball hit by a cue ball. The fast-moving argon atom then acts like an ionizing particle. It creates photons and causes the liquid to scintillate. Differences in the timing and duration of the scintillation light allow researchers to identify the types of particles that cause the scintillation. Image: Sandbox Studio

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The LUX detector, which allows charged particles to drift to a detector in much the same way a Time Projection Chamber does, is scheduled to move underground in late 2011.

EXO’S MOTTO: YOU CAN’T BE TOO CLEANExpense is just one reason that xenon detectors stay small. Although pure xenon contains no radioactive isotopes of its own, it can become contaminated, and removing contaminants is a crucial and arduous task. Even a few radioactive isotopes of krypton or argon among a billion atoms of xenon could compromise an experiment.

“People have been trying to play around with xenon for a long time and found it extremely complicated and very difficult to deal with,” says Giorgio Gratta, spokesperson for EXO, the Enriched Xenon Observatory at SLAC National Accelerator Laboratory. “The semiconductor industry has produced the incentive to build much better, cleaner vacuum equipment, with applica-tions for purifying xenon; it’s a classical example of science and technology going hand in hand. Cleaning xenon suddenly got much easier.”

No one needs clean more than EXO, an experiment that seeks to determine whether neutrinos are their own antiparticles. The super-rare subatomic decay it hopes to spot would occur even less often than a simple neutrino interaction.

Cached in a New Mexico salt mine to protect it from cosmic rays, the EXO200 detector surrounds its liquid xenon with specially extracted and produced copper and acrylics to filter out any trace of radiation. EXO scientists hope that the scintillating xenon isotope in their detector, xenon 136, can cast some light on neutrinos’ ability to flip between particles and antiparticles.

“We’re married to xenon,” Gratta says. For the 200 kilograms of xenon in the EXO200

detector, the EXO group borrowed two tons of the noble gas from a Russian military instal-lation, extracted the xenon 136 that made up 9 percent of it using a Russian centrifuge intended for uranium enrichment, and returned the rest. EXO200 began running in 2010, and plans are under way for a bigger detector.

Despite the struggle to keep xenon clean, Gratta finds the project immensely enjoyable: “You’re in a mine, looking for some strange nuclear decay, using cryogenic equipment and enriched xenon from a military complex in Russia. It’s lots of fun if you use your imagination.”

Generous amounts of imagination and plenty of painstaking effort will make the next few years an exciting time for experiments with noble liquid detectors. As scientists learn to manipulate these elite substances, the power of using them to search for nature’s rarest phenomena emerges.

The Large Underground Xenon experiment will use a two- phase liquid/gas xenon detector to look for dark-matter particles when it begins operating later this year in South Dakota’s Homestake Mine. The photomultipliers located at the top and bottom of the LUX detector will identify the distinctive flashes of light caused by dark-matter particles passing through. Photo: Carlos Faham, Brown University

The ICARUS experiment at Italy’s Gran Sasso National Laboratory is a pioneer in the use of liquid-argon technology to detect neutrinos. Like a bubble chamber from the early days of particle physics, the 600-ton detector allows scientists to record the tracks of the charged particles that a neutrino produces—but with electronics, rather than with photographs. Photo: Gran Sasso National Laboratory/INFN

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Paul Gueye wades into the crowd and clears a circle on the ground for a piece of wood the size of a tractor tire with a leaf blower protruding from its center. He gestures for a boy to sit on what looks like a homemade version of a Sit ’n Spin toy.

Within seconds the boy is hovering inches off the ground. His smile widens as he floats forward, as if riding a giant air hockey puck.

The physics of force and reaction convey this “magical” ability to hover, the crowd hears from Gueye, who studies quarks at Thomas Jefferson National Accelerator Facility in Virginia. He hopes the lesson sinks in, but if not, that’s OK. For now, exclamations of “Cool!” emanatiing from the crowd will do.

Ooh-and-ahh moments are a staple of the largest national sci-ence and engineering festival ever held. More than 1500 hands-on exhibits and 75 stage shows on and near the Washington, DC, National Mall highlight the wonders of science.

Inner-city students line up for autographs from Nobel laureate Leon Lederman, discoverer of the muon neutrino. Girl Scouts rush from exhibit to exhibit to earn merit badges and come face to face with dozens of female biologists, mathematicians and physicists. Parents with children from preschool to high school join retirees, school children on field trips and vacationers milling about the inaugural US Science and Engineering Festival during a late October 2010 weekend.

Close to a million people spend the weekend listening to rappers and comedians promote the fascination of science. They wield hammers made with bananas dipped in liquid nitrogen and eat DNA helixes made of marshmallow and toothpicks. Building on the event’s success, a second festival is planned in Washington, DC, April 27–29, 2012.

While the festival features fun for young and old, leaders of industry, government and academia consider it serious business. The need to reinvigorate the nation’s commitment to science, engineering and math has drawn together 850 universities, schools, companies, science and engineering societies, research organiza-tions, and federal funding agencies, including the Department of Energy, which contributes funding and exhibits.

Biotech entrepreneur Larry Bock conceived of the festival after seeing similar expos in Europe and struggling to find qualified Americans to fill advanced science and engineering positions in his companies. US universities award two-thirds of PhD degrees in engineering to non-US citizens, and more English-speaking engineers come from China than from the US, according to Norm Augustine, former CEO of Lockheed Martin and festival host.

“We are outsourcing our security, our medical, everything. That’s scary,” says teacher Judith Haskins, as she watches Fermilab sci-entists explain research at the only US national laboratory devoted

to high-energy physics.Often, the spark of interest in science

begins to fade in the early grades. By age 15, US students rank 21st in science

among students in 30 developed nations, according to a 2006 study quoted by Alan Leshner, CEO of

the American Association for the Advancement of Science.

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day in the life: science fest

SCIENCE FEST FEEDS HUNGER FOR KNOWLEDGE

Hammering nails with a banana to spark interest in science and technology

BY TONA KUNZ

Below: Physicist Paul Gueye push starts a hovercraft powered by a leaf blower to demonstrate principles of force and motion.

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Top: More than 1 million people con-verged on the National Mall for a week-end science fest. Middle top: Fermilab Nobel laureate Leon Lederman signs autographs. Middle bottom: Brookhaven National Laboratory uses races to teach kids about magnet technology. Left: Children learn how designers use math to attach shapes to form a giant ball.

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day in the life: science fest

Left: Eager children catch balls flung by a robot built by teenagers. Below: At the Smithsonian Astrophysical Observatory booth, children build mod-els of the universe by putting marbles in jars. Colored marbles represent reg-ular matter, which constitutes just 4 percent of the universe; black marbles stand for the resist, made up of dark matter and dark energy.

Far left: Children strain to touch soap bubbles created in a liquid nitrogen explosion at Fermilab’s Mr. Freeze show, which demonstrates how cryo-genics work and how that ties into the lab’s experiments. Below left: Galileo, the father of modern observational astronomy, shows off improvements to his telescope.

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Ruth Van de Water knows how that spark needs nurturing. She urges youngsters to give science a second chance as she uses a ball-rolling game to demonstrate how physicists use particle colli-sions to probe subatomic particles.

Van de Water, a physicist studying rare particle interactions at DOE’s Brookhaven National Laboratory in New York, tells the children that she got C’s in high school physics and found it boring. A required college physics class exposed the would-be chemistry major to a more interesting teaching method and led her to a career in physics.

“It was fun, and I liked the people going into it,” she says. Haskins and fellow teachers at a Virginia elementary school

hope to give the 150 school children they have brought to the festival that same kind of “aha” moment. They are on a crusade to get kids involved in science at the earliest age. They struggle with how to interest students, as well as with the notion that people have to be “rocket-scientist smart” to do science.

“That is just not true,” Van de Water says. “You have to be aver-agely smart and then you have to work really hard. I don’t think this comes easy to anyone at all.” But neither do careers such as medicine or quarterbacking for the Chicago Bears.

Vanessa McNeil, of Washington, DC, brought her 7- and 3-year-old daughters to the festival to show them the varieties of science. The girls walk wide-eyed through a mock accelerator tunnel pulsing with lights. Pretending to be a neutron beam in the spallation neutron source at Oak Ridge National Laboratory in Tennessee, the girls eventually collide with a mock target, pushing a wall button and igniting a burst of red and blue light. Little jaws drop; mom smiles.

“I just want to keep them interested, even if they don’t go into science,” McNeil says. “Science and math are in every part of our lives, even if I’m baking cookies.”

Top: Vanessa McNeil and her daughters follow the path of a neutron in a mock-up of the Oak Ridge National Laboratory’s Spallation Neutron Source accelerator. Middle: Staff at the DOE booth explain emerging tech-nologies and sustainability programs. Bottom: Giant prisms demonstrate light refraction.

KEY COM PON E NTS FOR TH E DAR K E N E RGY SU RVEY:

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JAPAN

deconstruction: dark energy camera goes to chile

Doing big science takes big effort and big cooperation. Building and installing one

of the world’s largest digital cameras to conduct the most extensive galaxy survey

to date requires scientists and manufacturers from across the globe. Researchers

from 26 institutions enlisted the help of 129 companies in the United States and

about half a dozen foreign ones to fabricate the often one-of-a-kind components

for the Dark Energy Camera. By Tona Kunz

Filters for five colors, or wavelengths, of light allow the camera to determine galaxy distances by their red-shifts. Worked on by a Japanese company.

One of clearest sky views in the world provided by Chile’s 4-meter Blanco telescope, which will hold the camera.

World’s largest shutter to take pictures every two minutes. Made by Bonn University and the Arlanger Institute.

S MALLE R COM PON E NTSNumerous smaller components were made by companies in Hungary and in 25 US states: Arkansas, Arizona, California, Colorado, Connecticut, Florida, Ohio, Illinois, Indiana, Maine, Michigan, Minnesota, New Hampshire, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Tennessee, Texas, Washington, Wisconsin, Virginia, Vermont.

Instrument-control soft-ware that controls camera components as they survey the sky. Made by Ohio State University and University of Illinois at Urbana-Champaign.

Most sensitive photo chips, or CCDs, for red and infrared light. Developed and partially processed by Berkeley Lab; assembled and tested by Fermilab.

Camera imager to measure galaxy distri-butions, supernovae, and distortions caused by dark matter. Designed and assem-bled at Fermilab.

One-of-a-kind cryo-genics system to keep photo chips at minus 100 degrees Celsius. Designed and assembled at Fermilab.

Image readout boards record 300-plus images a night, each containing about 200,000 galaxies. Made by Spanish insti-tutions IFAE and CIEMAT with Fermilab design help.

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10World’s largest filter changer to identify light that left galaxies 9 billion years ago. Made by University of Michigan.

Five lenses, the biggest almost 1 meter in diame-ter. Made by a company in New York, polished by a French company, and assembled by University College London.

Precision hexapod to help align a 3-ton camera to within a few microns. The camera will perform the world’s most exten-sive optical sky survey. Made by an Italian firm.

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Most components for the camera, part of the Dark Energy Survey, migrate to the Department of Energy’s Fermilab for testing before heading to the 4-meter Blanco telescope in the remote Chilean mountains. The journey requires help from planes, trains, trucks and boats to traverse conti-nents and oceans, and ends with an 11-hour drive to a mountaintop.

The DES’s combination of survey area and depth will far surpass what has come before and provide researchers for the first time with four search tech-niques in one powerful instrument. To find clues to the characteristics of dark energy and why the

expansion of the universe is accelerating, DES will trace the history of the expanding universe roughly three-quarters of the way back to the time of the big bang.

During five years of operation, starting in 2012, the 570-megapixel camera will create in-depth color images of one-eighth of the sky, or 5000 square degrees, to measure 100,000 galaxy clusters, 4000 supernovae, and an estimated 300 million distant galaxies, about 10 million times fainter than the dimmest star you can see from Earth with the naked eye. It will yield the largest 3-D map of the cosmic web of large-scale structures in the universe.

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Image: Sandbox Studio; Photos: DES collaboration, NOAO

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accelerator apps: diapers

Accelerators help keep baby dry In the United States, we buy more than 20 billion disposable diapers each year. That’s a lot of baby bottoms to keep dry, and parents every-where can thank particle accelerators for doing their part.

About a decade ago, researchers at the Dow Chemical Company teamed up with Lawrence Berkeley National Laboratory to use the Advanced Light Source to develop materials for the optimal baby diaper.

When it comes to diapers, consumers look for a product that is as thin as possible but still holds a lot of moisture and doesn’t leak. The answer: superabsorbent polymers.

No longer fluffy cotton, the active ingredient in today’s diapers consists of superabsorbent polymer beads, long chains of interlinked mole-cules that can hold copious amounts of liquid. Each bead has a special layer on the outside that creates a seal after liquid gets absorbed so it won’t leak back out.

Companies like Dow started manufacturing the polymer beads in the ‘90s, but to make a leak-proof product, chemists needed to see the

microscopic details of the material. That’s where the synchrotron light source at Berkeley came in.

“What really counts is how the material per-forms when it is wet, and you can’t see that with a regular microscope,” says Adam Hitchcock, a professor of chemistry at McMaster University and Canada Research Chair for Materials Analysis at the Canadian Light Source.

Using X-ray microscopy, a technique devel-oped by Hitchcock and his collaborators, Dow chemists were able for the first time to see the detailed structure of the superabsorbent poly-mer material while wet. Dow brought a variety of samples to the ALS to analyze, and the X-ray microscopy technique enabled the chem-ists to adjust and improve the formula for the superabsorbent polymers until they had the perfect diaper.

“They were trying to find the magic recipe, and we were the feedback tool,” Hitchcock said.

Dow used the results from the ALS research to design production processes at new superab-sorbent polymer fabrication plants. All modern-day diapers now contain the superabsorbent polymer beads, keeping babies dry and parents happy.Elizabeth Clements

www.symmetrymagazine.org/archive/apps

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mount samples and align an instrument in one of sev-eral small hutches grafted onto an 80-meter accelerator ring at what is now SLAC National Accelerator Laboratory. The hutches were part of a cutting-edge initiative called the Stanford Synchrotron Radiation Project; and the experi-ment they performed that day would demonstrate a pow-erful new tool for determining the structures of proteins.

The basic method, then and now, was to turn many copies of a protein into a small crystal and hit it with X-rays, which scatter and form a diffraction pattern. Scientists interpret the pattern to determine the protein’s molecular structure. However, previous X-ray sources had been too weak to study the smallest crystals and most complex proteins. Now the scientists at SLAC would try a much more intense source: X-rays emitted by electrons speeding around the SPEAR storage ring. This form of X-ray light is known as synchrotron radiation.

Working in a team led by Keith Hodgson, then assistant professor of chemistry at Stanford University, the scien-tists spent hours reaching through a narrow slit in the hutch to tweak the alignment of their apparatus, then closed and locked the hutch and let the X-rays in. The X-rays scattered off a single crystal of a protein called rubredoxin and left this pattern on high-resolution X-ray film.

“We were very happy,” recalls James Phillips of Iowa State University, then a 23-year-old Stanford graduate student. The news quickly spread among the hutches, and a senior scientist uncorked a bottle of champagne. The team’s published report was the first to describe the successful use of synchrotron radiation for protein crystallography.

Those first experiments, along with others in Germany and the Soviet Union, set off a revolution in structural biol-ogy. Today, scientists at 22 synchrotron light sources are analyzing protein structures, and the worldwide Protein Data Bank contains the structures of more than 72,000 proteins.Glennda Chui

Synchrotron radiation is the light emitted by

charged particles as they accelerate—whether they’re gaining speed along a straight line or traveling at a constant speed on a curved path. (Moving along a curve involves acceleration; we feel this type of acceleration when we drive a car around a corner.)

Synchrotron light gets its name from the synchrotron particle accelerators where it was first observed. Synchrotrons use magnets to bend the paths of speeding electrons into arcs. But we also see it in the cosmic realm: some of the light emitted by astronomical objects such as the Crab Nebula comes from electrons swooping through galactic mag-netic fields.

When accelerated, low-mass particles such as electrons lose far more energy to synchrotron radiation than heavy particles like protons do. That’s why scientists use electrons, not protons, to harvest the power of synchrotron radiation in facilities called light sources. There the electrons travel in circles or slalom through magnets known as wigglers or undulators. They radiate extremely intense light in a direction tangential to the curved path they’re on, like mud flung from a spinning tire or sparks from spinning fireworks. Scientists choose a specific wavelength of light from the broad range that the electrons emit, including infrared, ultraviolet, X-ray, and visible light, and focus it on very small samples. The combination of intensity and tunability makes synchrotron radiation a powerful all-purpose tool for research in many fields, yielding detailed information on structures as small as atoms and molecules.Herman Winick, SLAC National Accelerator Laboratory

symmetryA joint Fermilab/SLAC publicationPO Box 500MS 206Batavia Illinois 60510USA

symmetry

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