Final LHC magnet goes underground

April 30, 2009 | 11:32 am

A replacement LHC magnet being lowered into the tunnel. Photo: CERN

CERN issued this press release today

The 53rd and final replacement magnet for CERN’s Large Hadron Collider (LHC) was lowered into the accelerator’s tunnel today, marking the end of repair work above ground following an incident in September last year that brought LHC operations to a halt. Underground, the magnets are being interconnected, and new systems installed to prevent similar incidents happening again. The LHC is scheduled to restart in the autumn, and to run continuously until sufficient data have been accumulated for the LHC experiments to announce their first results.

“This is an important milestone in the repair process,” said CERN’s Director for Accelerators and Technology, Steve Myers. “It gets us close to where we were before the incident, and allows us to concentrate our efforts on installing the systems that will ensure a similar incident won’t happen again.”

The final magnet, a quadrupole designed to focus the beam, was lowered this afternoon and has started its journey to Sector 3-4, scene of the September incident. With all the magnets now underground, work in the tunnel will focus on connecting the magnets together and installing new safety systems, while on the surface, teams will shift their attention to replenishing the LHC’s supply of spare magnets.

In total 53 magnets were removed from Sector 3-4. Sixteen that sustained minimal damage were refurbished and put back into the tunnel. The remaining 37 were replaced by spares and will themselves be refurbished to provide spares for the future.

“Now we will split our team into two parts,” explained Lucio Rossi, Deputy head of CERN’s Technology Department. “The main group will carry out interconnection work in the tunnel while a second will rebuild our stock of spare magnets.”

The LHC repair process can be divided into three parts. Firstly, the repair itself, which is nearing completion with the installation of the last magnet today. Secondly, systems are being installed to monitor the LHC closely and ensure that similar incidents to that of last September cannot happen again. This work will continue into the summer. Finally, extra pressure relief valves are being installed to release helium in a safe and controlled manner should there be leaks inside the LHC’s cryostat at any time in the machine’s projected 15-20 year operational lifetime.

CERN is publishing regular updates on the LHC in its internal Bulletin, available at http://www.cern.ch/bulletin, as well as via twitter and YouTube at http://www.twitter.com/cern and http://www.youtube.com/cern

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Gamma signature, Astronomer’s Telegram cast light on dazzling blazar

April 30, 2009 | 11:22 am

Fermi Gamma-ray Space Telescope's all-sky gamma map, with Blazar 3C 454.3 labeled in the lower left corner. (Image: NASA/DOE/International LAT collaboration.)

When it comes to watching the skies, two sets of eyes are always better than one, especially if one pair can see, say, radio waves, while the other has X-ray or even gamma-ray vision. The Fermi Gamma-ray Space Telescope’s Large Area Telescope collaboration has recently released a paper giving the gamma-ray perspective on an astronomical object that flared last summer, an active galactic nucleus-or quasar-known as 3C 454.3. The paper, accepted by the Astrophysical Journal and posted yesterday on the ArXiv preprint archive, reveals that the structure of these distant, energetic monsters is more complex than scientists had previously guessed. The paper also hints at a more comprehensive picture to come, next time unfolding in full color, using data from radio, infrared, optical, X-ray, and gamma bands.

A quasar is thought to be fueled by an enormous swirl of gas, or accretion disk, that has gathered around a massive black hole at the center of a distant galaxy. As gas particles stream into the black hole’s maw, protons and electrons near the black hole are propelled outward at close to light speeds in a jet perpendicular to the disk. When this jet outshines the surrounding galaxy, it’s often called a blazar-perhaps one of nature’s most powerful particle accelerators. In a process that’s poorly understood, the jets quake and shudder, shaking the high-energy beams and causing them to radiate.

“We don’t see the particles unless they produce some signature of their presence,” said SLAC National Accelerator Laboratory astrophysicist Greg Madejski, who with Benoit Lott of France’s National Institue of Nuclear and Particle Physics at Bordeaux, coordinated the work on the paper. “It’s like peeling an onion-we look at the radiation and look at what produces the radiation, then that tells us about the content and structure of the jet.”

In the summer of 2008, Blazar 3 C 454.3 flared violently, dazzling the Large Area Telescope, or LAT, with a gamma-ray blaze. Using data collected over the next month, astrophysicists uncovered unexpected complications in the gamma-ray portion of the blazar’s radiation-corresponding to energies between 20 MeV and 300 GeV. So far, gamma-ray observations of blazars have indicated that the amount of radiation emitted decreases as its energy increases. This relationship seems to follow a power law, so that a gamma ray with twice the energy of another is about one fourth as common. The new LAT data show a break in the expected smooth downward decline, with a sudden drop in the amount of radiation at about 2 GeV.

Today's astronomical telegrams are the electronic descendents of physical telegrams like this 1922 circular of the International Astronomical Union heralding the observation of a new comet. (Image: the International Astronomical Union.)

The gamma-ray data allow astrophysicists to make important revisions to the prevailing picture of blazars. Meanwhile, multi-wavelength data promise even deeper insights. As their own telescope tracked the gamma rays, the LAT collaboration leapt to action, alerting astronomers all over the world to the flaring blazar. Their July 24 posting on the Web site The Astronomer’s Telegram triggered an unplanned yet successful multi-wavelength campaign, securing observations in the radio, infrared, optical, ultraviolet and X-ray bands.

“This is really the only way to make any progress,” Madejski said. “It turns out what we really want to find out is who flares first-is it the gamma rays and then the optical and infrared, or vice versa? This tells us what the ‘prime mover’ behind these flares might be.”

For more than a century, astronomical news was sent from one observatory to another in Morse code, via miles of wire. Today’s astronomers use online resources, such as the International Astronomical Union e-mails and The Astronomer’s Telegram, to find the hottest things to watch. According to SLAC astrophysicist Jim Chiang, the LAT collaboration has posted more than 20 telegrams since January. As an all-sky monitor sensitive to gamma rays, the LAT is especially well-poised to launch broadband investigations of events like blazar flares, which are fleeting and tend to glow most brightly in the high-energy part of the spectrum.

“These guys will flare on a timescale of a few days, or they may stay hot. It’s important to trigger these campaigns on a timely basis,” Chiang said. “This is a new thing that we’re able to do with the LAT.”

“Understanding of Fermi data requires collaboration with astronomers and astrophysicists observing in other spectral bands,” Madejski added. “If we invite them to look at unusual celestial phenomena, it will shed light on these enigmatic sources of extremely energetic radiation.”

By Lauren Schenkman

This story first appeared in SLAC Today on April 30, 2009.

Symmetry Intern

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A new way to draw women from industry to science academia

April 29, 2009 | 7:14 am

A new National Science Foundation grant is taking a new tack to fix the long-term problem of a shortage of women in the sciences.

The idea behind the On-Ramps in Academia workshops is to lure women from private industry into academia, rather than the previous pattern of schools fighting over a limited pool of candidates already in academia, a  zero-sum strategy.

According to the American Institute of Physics, as of 2003, women receive 22 percent of the bachelor’s of science and arts degrees in physics, but only 18 percent of the PhDs. Additionally, only 5 percent of full professors in physics were women in 2002.

Likewise, women are severely underrepresented in the other physical sciences and engineering.

Women in the science, technology, engineering, and mathematical professions represented 26.1 percent of those fields in 2003, a jump from 7 percent in 1983 and 2003, according to the Association for Women in Science.

You can learn more about women in science and engineering, particularly in physics, on a new Web site Women in Physics hosted by Fermilab.

Tona Kunz

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Drinking tea with the LHC

April 28, 2009 | 7:06 pm

Playwright and actor Richard Dormer as a physicist who has discovered the Higgs boson.

“It’s not at all difficult to make science funny,” says playwright and actor Richard Dormer. Anyone who has sat through an actual lecture on quantum mechanics may have their doubts, but Dormer says his latest play, a black comedy rooted in high-energy physics, has successfully engaged audiences with physics subject-matter in a light-hearted way.

“At first they’re going, ‘Uh oh,’ but at the end of the play they’ve all been telling me it’s perfectly clear what’s happening,” he says. “The audience is getting things explained to them in a funny way. I think they feel kind of enlightened by it.”

The Gentlemen’s Tea-Drinking Society follows four middle-aged Cambridge graduates who have reunited yearly since their undergraduate days. They’re in varying states of career frustration, but one of them, a physicist named Brian, played by Dormer, has a secret-he’s discovered the Higgs boson in a particle accelerator constructed in an abandoned section of the London underground. It’s a humorous, science-fiction take off the now-familiar Large Hadron Collider.

“I found the nature of what they’re trying to do at the LHC very exciting, that quest and journey into the unknown,” Dormer says. But to write jokes about quantum mechanics and particle physics, he had to do his homework.

“I read all the beginner guides-A Brief History of Time, A Briefer History of Time,” Dormer quips. “I had to learn it from scratch. That whole world is kind of bewildering, but I really enjoyed it, and I kind of got inspired by it.”

This spring the play traveled from Dormer’s native Belfast through Northern Ireland and Ireland before ending its run in Glasgow, Scotland. Dormer still has no plans to take The Gentlemen’s Tea-Drinking Society to the LHC.

“I’d love to, but they’d have to invite us. But they’d be going, this is preposterous, you can’t do this, you can’t do that,” he says. They also might object to play’s ending; Brian’s discovery of the Higgs particle leads to an apocalyptic scenario, hardly the kind of media the LHC needs. But, Dormer insists, “I’m not trying to warn people about the LHC.” The play, he says, is as much about academic squabbles, middle age, and friendship as it is about physics.

“The thing is if you root science in something every day that people can understand, they will see it as funny and not some alien artifact,” Dormer says. “They can embrace it.”

Reviewers don’t seem to know what to make of the play. Jay Richardson of The Scotsman complains of a ” confusing, ongoing allusion to Schrödinger’s cat,” while The Stage‘s Jane Coyle calls it “a tribute to…the daring of [Dormer's] imagination that such unpromising subject matter could be…transformed into a riveting evening’s entertainment.”

In any case, the British Council seems to buy the unusual combination of science and comedy. They’ve selected the play for their annual showcase of the best of British theater, which will run alongside the International Festival and Fringe this August in Edinburgh, Scotland. So if Edinburgh native Peter Higgs is wondering what Dormer has made of his theory, he won’t have far to look.

by Lauren Schenkman

Symmetry Intern

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Gamma plus radio equals new view of cosmic jets

April 27, 2009 | 6:13 am

The radio jets of several active galaxies mapped by the Very Long Baseline Array (VLBA) are inset into the Fermi Gamma-ray Space Telescope’s map of the gamma-ray sky. Credit: NASA/DOE/Fermi LAT Collaboration and NRAO/AUI/MOJAVE Team/M. Kadler

The sky map and list of bright sources based on Fermi Gamma-ray Space Telescope’s first three months of operation are already yielding fruit. An international team of researchers participating in the MOJAVE program has correlated radio-wave data with Fermi’s gamma-ray findings to move toward a better understanding of the physics behind the universe’s most energetic objects.

The team used the Very Long Baseline Array, or VLBA, a set of ten radio telescopes operated by the National Radio Astronomy Observatory. Spanning North America from Hawaii in the west to the US Virgin Islands in the east, the telescopes act as one continent-sized dish, collecting radio-wave data on some of the brightest gamma-ray sources the Fermi telescope sees. These are active galactic nuclei, swirls of gas particles around supermassive black holes that spurt two opposing jets of highly energetic particles. The radio data show that nuclei with radio jets pointed straight at Earth are more likely to be detected by Fermi in gamma-ray wavelengths. The researchers also found that the jets from the brightest gamma-ray sources flare in radio waves at the same time.

Jim Chiang, an astrophysicist with Fermi’s Large Area Telescope collaboration at SLAC National Accelerator Laboratory, says the results support a model of active galactic nuclei in which the jets are responsible for both radio waves and gamma rays.

“This confirms that there is a connection between ejection of the blobs seen in radio waves and the production of gamma-ray emission,” Chiang says. “Now we actually have quantitative measurements of how the models should predict these effects. We can test these models concretely in terms of numbers.”

Stanford astrophysicist Peter Michelson, the lead scientist on the LAT, says he is pleased to see Fermi telescope data being used in a multi-wavelength study. Broadband examination of active galactic nuclei, he says, is one of the goals of the Fermi telescope, and critical to unraveling their mysteries.

“The bright-sources list was really intended primarily to inform the rest of the scientific community as to what we’re seeing with Fermi,” he says. That way telescopes working in other wavelengths, from radio waves to X-rays, can study these objects, “and we can correlate the emissions across as much of the electromagnetic spectrum as we can.

“We’re pretty happy with it, and we’ll see a lot more of this in the future,” he adds. “This is just the start, really.”

MOJAVE, which stands for Monitoring Of Jets in Active galactic nuclei with VLBA Experiments, involves astronomers throughout the United States and Europe. The results are reported in two papers in the May 1 issue of the Astrophysical Journal; they can be found here and here. For more information, see the NASA press release.

by Lauren Schenkman

Symmetry Intern

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Einstein could be your child's next teacher

April 24, 2009 | 8:26 pm

Geez! Even Einstein as a robot is super smart.

Take a look at this video clip of robot Einstein, an “emotionally intelligent machine”. It’s created by the University of California, San Diego and the National Science Foundation. It can track your eye movements and mimic your expressions.

For some, it’s one step deeper into the uncanny valley.

Tona Kunz

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World's first hard X-ray laser switches on

April 21, 2009 | 10:50 am

Only 12 of a total 33 LCLS undulator magnets (silver-tone oblongs) were needed to create the first pulses of laser light. Photo: SLAC

In a stunning piece of engineering, the Linac Coherent Light Source at SLAC National Accelerator Laboratory has created X-ray laser light immediately after being switched on. It is the first time that an X-ray laser has operated at such short wavelengths, with such brightness and short pulses.

The laser paves the way to a new way of looking at not only the structure of matter but also its dynamics. By using laser pulses of less than 100 femtosecond duration, the dynamics of chemical reactions can be caught in process, and the machine promises to be able to image single molecules.

The LCLS is based on the last kilometer of SLAC’s linear accelerator, which was previously used to drive particle physics experiments but has been adapted to this new use. LCLS Construction Project Director John Galayda was clearly still shocked at how smoothly the turn on had gone, saying, “It worked so beautifully I just can’t believe it…We were all just dumbfounded, standing there looking at the light.”

An X-ray laser pulse as seen in SLAC's Main Control Center. A point of laser light seen here in the middle of a larger halo of dimmer, non-coherent X-rays. The surrounding blue halo is more like the X-rays produced at a synchrotron accelerator; the tiny, distinct pinpoint in the middle is the laser pulse from the LCLS. Image: SLAC

Initial goals for the LCLS were to switch it on and achieve laser light at a wavelength of 15 Angstroms, or 1.5 nanometers. Researchers would then attempt to tune the system to get the wavelength down to 1.5 Angstroms, or 0.15 nanometers, with the better resolving power they would provide. However, the laser immediately started working at the higher-energy, shorter wavelengths.

Furthermore, the laser is achieving almost full saturation. That means all the laser power is going into creating laser-type photons rather than non-coherent photons which are still X-ray light but not with laser properties. That saturation was expected to take weeks or months of tuning to achieve.

SLAC Director Persis Drell said, “I thought the first signs of lasing would be subtle. In fact, it was blasting. This is not shy, this is a very confident instrument.”

The LCLS is a free-electron laser that works by passing a high-energy electron beam through a series of undulators, which are magnets that bend the electron beam back and forth very rapidly, thereby causing the electrons to emit X-rays. The geometry of the system causes the X-rays produced to stimulate the emission of more X-rays, and it is that process which makes it a laser. However, this lasing process happens as the electrons and light travel in just one direction down the length of the machine, unlike conventional lasers which require a cavity for the light to bounce back and forth and build up the coherent, in-step photons that constitute a laser. Previous free-electron lasers have created light at other wavelengths including the ultraviolet and in low-energy “soft” X-rays. The LCLS has produced the first “hard” X-rays at such short wavelengths.

The physical size of the LCLS laser spot is about two-tenths of a millimeter. Like light from a flashlight, most light sources diverge to create a large spot some distance away. The LCLS laser light is tightly focused onto this sub-millimeter diameter despite having traveled a considerable distance from its source. Image: SLAC

The LCLS will be further tuned as various experiments to understand the properties of this new type of laser commence. In coming months, the first instruments will be installed to use the X-rays to perform experiments on samples with a view to making images of single molecules, and start to explore the dynamics of chemical reactions.

Further information in a press release, fact sheet, and video interview from SLAC.

David Harris

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A story of the people who shaped Fermilab

April 21, 2009 | 7:01 am

Fermi National Accelerator Laboratory in Batavia, Illinois, probes the largest questions in the universe by looking at the world’s smallest particles. But all that ground-breaking science doesn’t occur in a cultural vacuum. Discoveries have evolved amidst a back story of people, politics, and even art.

With the release of a new book Fermilab: Physics, the Frontier and Megascience, three women who have spent years at the flagship laboratory for American high-energy particle physics, provide a historical view of how big science happens. They also reveal some of the little known facts surrounding the “laboratory on the prairie”, including what the tall sculpture in the middle of the pond in front of Wilson Hall represents and why Fermilab’s mailing address is Batavia instead of Warrenville.

The book is a must-read for science and Illinois history buffs as well as anyone who has ever worked at or visited Fermilab. This first widely published history of Fermilab gains its strength from the close ties its authors have with the laboratory.

Adrienne Kolb

Adrienne Kolb has been an archivist at Fermilab for 25 years; Lillian Hoddeson is Fermilab’s historian and a history of science professor at the University of Illinois-Urbana Champaign; and Catherine Westfall wrote her PhD dissertation on Fermilab and is currently a visiting history professor at Michigan State University.

Their comprehensive history of Fermilab is largely told through portraits of the two leaders who have most shaped the institution: Robert Rathbun Wilson, the first director; and his successor, Leon Lederman. The authors write: “While Wilson’s image was based on his personae as pioneer, engineer and Renaissance man; Lederman’s rested on his all-embracing passion for physics.”

Lillian Hoddeson

The authors’ human-interest angle, which focuses on the people who shaped Fermilab through 1998, will interest general readers and specialists alike. The book is rich with historical and scientific details, and it includes many citations from interviews and collected oral histories, which make for a very lively account.

The authors frame the book around the three themes mentioned in the sub-title: Physics, the Frontier and Megascience. The US government, through the Department of Energy’s predecessor, the Atomic Energy Commission, appointed Wilson to lead the National Accelerator Laboratory in 1967. At this time, the goal for particle physics was to move significantly beyond the 30 GeV energy threshold being examined by Brookhaven National Laboratory and CERN, the European particle physics laboratory located in Switzerland.

Catherine Westfall

Wilson wanted to take his field even further with an accelerator designed to reach 500 GeV. To highlight that, Fermilab lore has it, Wilson asked post offices in towns surrounding Fermilab to give him a Post Office Box number 500 for the laboratory. Batavia was the only town with such a high number, so the laboratory chose a Batavia mailing address.

The second part of the book, “A New Frontier on the Illinois Prairie,” discusses how Wilson crafted Fermilab with an eye to his own upbringing on  the plains of Wyoming. Fermilab was established on farmland that would become one of the largest restored native prairies in the United States. In addition to Wilson’s efforts to plant hundreds of trees and shrubs, he also brought buffalo to Fermilab to highlight the connection between the area’s frontier past and laboratory’s goal to be on the frontier of science.

Under Wilson’s tenure, Fermilab turned on its 200 GeV proton accelerator, the Main Ring, in 1972.

Wilson also contributed to the aesthetics of Fermilab. One of his contributions to the sculptures dotting the site is the steel obelisk in the pond in front of Wilson Hall. He called it “Acqua alle Funi,” which in Italian means “water to the ropes.” That phrase was a rallying cry in 16th century Rome when workers raised an obelisk to its vertical height at St. Peter’s Square, using ropes that needed water to work properly. At Fermilab, it became the rallying cry during the final months of construction of the main accelerator ring, which is surrounded by water used to cool magnets heated up by particles pushed to ever faster speeds.

In 1978, Wilson left the directorship to Leon Lederman, a physics professor at Columbia University. The third part of the book, “The Road to Megascience,” discusses the accomplishments during Lederman’s tenure. According to the authors, the “unabashedly romantic” leader often said: “The life of a physicist is filled with anxiety, pain, hardship, tension, attacks of hopelessness, depression and discouragement. But that the epiphanies made it all worthwhile.”

Lederman also made Fermilab feel more like a home to scientists from all over the world. He created the Chez Leon restaurant and the children’s center. He also started a program for high school students called Saturday Morning Physics.

The book does not skirt over the many tensions, mistakes, and disappointments Fermilab has known, nor the scientific details of the institution’s main endeavors. Physicists and other scientists would especially enjoy reading about the various ups and downs in experiments that predated their own.

For everyone else, the book is an engaging read and a real insight into one of the world’s most renowned physics institutions.

View a gallery of photos from the early days of Fermilab and read reviews of the book at the authors’ Web site.

The book is available for sale at the Lederman Education Center at Fermilab, as well as through area book stores and online at Amazon.com.

By Kristine Crane

Symmetry Intern

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Manhattan Project opened door for future women scientists

April 17, 2009 | 7:50 am

Ellen Weaver made her first scientific discovery at the height of World War II. She made lead and aluminum “sandwiches” that blocked radiation from uranium fission, projects that led to the construction of the atomic bomb. For some women, such as Weaver, the war had opened up a window of opportunity in the sciences.

Speaking in February at the American Association for the Advancement of Sciences meeting in Chicago, Weaver recalled her own inspired start as a scientist in the midst of war, followed by her struggles for equality in the war’s aftermath. Addressing an audience including many women scientists and science teachers, Weaver praised the fact that women today are represented in unprecedented levels in science. She encouraged women to push for even further advancements in fields where they still struggle for equality.

“There’s no question that the situation is better for women today, but there still seems to be a dearth of women in science policy positions,” said Weaver, in a phone interview following the conference.

Back in 1944, Weaver complained about unequal pay for the handful of women working as chemists at the Manhattan Project facility in Oak Ridge, Tennessee. She noted that women scientists are still paid less than their male counterparts. According to the Association for Women in Science, women in the science, technology, engineering, and mathematical professions are paid less than men, even as their representation in those fields increased by 7 percent, to 26.1 percent, between 1983 and 2003.

Even though the Army denied Weaver’s request for equal pay, she excelled quickly in her job as an analytical chemist, by proving her capabilities in making radiation-blocking sandwiches.

That was Weaver’s first job out of college. Even though she had a few women colleagues, there was very little camaraderie among them, she said.

“We viewed each other with a bit of hauteur,” Weaver said.  ”I think it was a subconscious thing. I don’t think I had any desire except to be a woman in a man’s place,”

It wasn’t until after the war, when Weaver went on to graduate school in genetics and meet the only other woman graduate student in biochemistry at Berkeley, that Weaver had her “eureka moment.” She realized that women need to work with each other to end discrimination. After that point, she started to rely on the support of other women to maneuver her way in a man’s world.

“The Fifties were a terrible time for women,” she said.  ”My thesis advisor told me, ‘No woman had ever amounted to anything in genetics at Berkeley.”

Because of her, younger women did not face that same hurdle.

Weaver completed her PhD in genetics at Berkeley, and eventually became a genetics professor at San Jose State University.

She wrote the foreword to the book Their Day in the Sun: Women of the Manhattan Project (Temple University Press, 1999), which recounts women’s participation in the Manhattan Project.

By Kristine Crane

Symmetry Intern

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Mush! Life of a dog-sledding astrophysicist

April 16, 2009 | 6:44 am

The latest issue of symmetry magazine included this story about astrophysicist Jen Adelman-McCarthy. When she’s not working on computer software for astrophysics experiments, Adelman-McCarthy spends time dog-sledding with her Husky, Behr. While demonstrating the sport at Fermilab, she talks about how her hobby fits into her life and why she adopted a Husky.

Kathryn Grim

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