A new era of synchrotron science at SLAC: PEP-X

July 3, 2008 | 6:38 am

Science at SLAC stands at the edge of an evolutionary leap. After a half-century of high-energy physics, SLAC’s scientific focus is shifting, with the decommissioning of the BaBar detector and PEP accelerator and the approaching completion of the Linac Coherent Light Source (LCLS). Among the wide diversity of scientific pursuits underway at SLAC, photon science—using very bright, energetic X-rays to probe the properties of matter—will soon constitute the major work of the laboratory.

That evolution is made possible by SLAC’s long history of learning from the past and building on its achievements. In 2009, the LCLS—the world’s first hard X-ray free-electron laser, which uses a portion of the historic two-mile linear accelerator as its backbone—will turn on, generating ultra-fast pulses of X-rays a billion times brighter than any source in the world.

Now, following that tradition of building on the past, scientists at SLAC are envisioning the future beyond the LCLS. By capitalizing on hardware and infrastructure already in place—namely, the recently decommissioned PEP-II facility—a new synchrotron storage ring project, “PEP-X,” would catapult SLAC even further beyond the research capabilities available at existing photon science laboratories.

A History of Light Source Science

More than 30 years ago, SLAC played a founding role in the genesis of light source science. At the time, the original SPEAR storage ring accelerator served primarily the high-energy physics research community, but its power as an X-ray source soon became apparent. The SPEAR machine evolved through subsequent generations, and for nearly two decades it has operated as a dedicated tool serving the photon science community. What began as a small project running on the coattails of SLAC’s high-energy physics program now represents the primary tool of photon scientists around the world. Over 60 such “synchrotron” light sources based on storage rings are currently operating globally.

In 2004, the Stanford Synchrotron Radiation Laboratory (SSRL) at SLAC commissioned the SPEAR3 storage ring, a “third-generation” light source optimized specifically for creating highly focused beams of X-rays useful for research in a vast range of disciplines. Thousands of scientists from around the world use SPEAR3 for research in a host of fields—chemistry, physics, environmental science, medicine, and biology, to name a few.

Next year, the completion of the LCLS will mark a major milestone in SLAC’s evolution into a world-leading photon science laboratory. Together, the two light sources—the SPEAR3 synchrotron facility and the LCLS—will provide X-ray scientists worldwide with a suite of scientific capabilities unavailable anywhere else. That expertise will be complemented by SLAC’s photon science research centers, PULSE and SIMES.

But ensuring that trajectory continues well into the future requires thinking beyond the LCLS. Although SPEAR3 remains one of the finest synchrotron light sources in the world, technical and scientific advances and the construction of competing facilities will, in a few years, eclipse the capabilities available at SPEAR3. A series of future upgrades for the LCLS are already in the works, but owing to a number of physical limitations of the SPEAR3 machine, similar upgrades to the storage ring are impractical.

Over the next decade, keeping pace with the world of photon science will require an entirely new synchrotron light source. But the good news is—owing to its legacy of high-energy physics—SLAC is already halfway there.

The recently decommissioned PEP accelerator was built nearly 20 years ago to store beams of electrons, again for SLAC’s high-energy physics program. In the late 1990s, the PEP accelerator was upgraded with more powerful systems to store electron–positron beams for the BaBar collaboration. Now, beneath the hills of SLAC, the PEP-II accelerator sits, in more than a mile of existing tunnel, unused and waiting for the next chapter in its already illustrious life.

The Next Synchrotron Light Source—PEP-X

The PEP-II accelerator facility is the ideal location for the next synchrotron light source at SLAC after SPEAR3. The PEP-X project would capitalize on the existing infrastructure, such as the accelerator tunnel, the high-power radio frequency accelerating system, and support utilities such as electrical and cooling networks. And because of its size—over a mile in circumference—PEP-X would create a steady stream of high average brightness X-rays unequaled at any other light source, a thousand times brighter than SPEAR3. PEP-X truly represents a leap in scientific capability at SLAC, and, by utilizing the existing infrastructure, one that could be completed at a savings of tens of millions of dollars.

Why Two Light Sources?

The LCLS, based on SLAC’s linear accelerator, represents an unprecedented leap away from conventional ring-like synchrotron sources. It opens completely new territory—but it does not replace the broad scientific capability of a synchrotron storage ring.

Although together the two light sources will serve complimentary purposes, a synchrotron light source such as PEP-X is a very different machine from the LCLS. The LCLS, prized for its “peak brightness,” packs unparalleled X-ray energy into very short, single pulses used, for example, to probe matter on very short time scales. One exciting aspect of the LCLS is the uncertainty as to how such unusual ultra-short and ultra-strong x-ray flashes will interact with matter. At present, scientists envision observing chemical bonds forming and breaking, or recording snapshots of materials transforming from one physical state to another—all of which occur within unimaginably short slivers of time.

A synchrotron storage ring, by contrast, provides a virtually continuous stream of X-rays. It is this feature that, despite much lower peak brightness, gives synchrotron light sources very high “average brightness.” In contrast to the intense LCLS X-ray pulses, synchrotron X-rays gently probe or continuously “tickle” a sample without disturbing its natural state. Synchrotrons, for instance, are used to determine the chemical and structural make-up of materials, for example, how atoms and molecules are arranged in proteins, or how elements are distributed in soil contaminants.

Together, two light sources offer the complementary qualities of peak flashes of brightness and continuous brightness. This enables scientists to study what materials are made of, and how their atoms are arranged and bonded; the electrons and their distribution, and how unusual phenomena arise from the mysterious property of electrons called the spin; and how the interactions between the three ingredients—atoms, electrons and their spins—vary with time, all down to the shortest timescales.

This article originally appeared in SLAC Today on June 2, 2008.

Brad Plummer

1 Comment »

GLAST spacecraft powered up and sending data

July 2, 2008 | 12:06 pm

Menlo Park, CA—After their journey into the cold reaches of space, instruments on the Gamma-ray Large Area Space Telescope have been woken up ready to begin operations. GLAST, a cooperative effort between NASA and the US Department of Energy, with key international contributions, has started sending signals back to Earth indicating that all systems are powered up and operational.

Data from the Large Area Telescope (LAT), one of two instruments aboard GLAST, is arriving at the Stanford Linear Accelerator Center’s Instrument Science Operations Center (ISOC) where it will be monitored, processed, and distributed to the rest of the science team worldwide. The observatory is commanded from the Mission Operations Center (MOC) at NASA Goddard Space Flight Center, and during the present initial on-orbit commissioning phase is staffed by a team from across the mission, including from SLAC.

ISOC manager Rob Cameron from SLAC said, “Powering up the LAT has been even smoother than we had hoped. Everything has worked well—in fact, it’s going great. We’re already receiving high-quality data that we can use to get the instrument ready for the best science return.”

Peter Michelson, of Stanford University, spokesperson and principal investigator for the LAT collaboration, said, “We’re off to a great start and we’re looking forward to a new view of our universe once science operations begin.”

GLAST will explore the most extreme environments in the universe, and seek answers to questions about dark matter, supermassive black hole systems, pulsars, and the origin of cosmic rays. It also will study the mystery of powerful explosions known as gamma-ray bursts.

Steve Ritz, NASA project scientist for GLAST, said, “Shipping data from the spacecraft down to earth, through the MOC to the ISOC, and ready for analysis is a great accomplishment, and it’s thanks to all the detailed testing and rehearsals by the whole mission team before launch.”

SLAC managed the LAT construction project and played a key role in assembling the instrument. With the operations phase of the mission now underway, SLAC plays the central role in LAT operations, data processing, and making scientific data available to collaborators for analysis.

LAT collaboration members from around the world are currently visiting SLAC to assist in the commissioning phase, meeting daily to bring the LAT to its mission-ready performance.

After the 60-day checkout and initial calibration period, the project will begin science operations. The LAT will perform a full-sky survey for the first year of the mission and will rapidly respond to gamma-ray bursts detected by both GLAST instruments.

Eduardo do Couto e Silva, a deputy manager of the ISOC at SLAC, said, “We can’t wait to see the gamma-ray sky through GLAST ‘eyes’ and to share with the world what we find in the months and years ahead.”

David Harris

No Comments »

GLAST launch celebration

July 2, 2008 | 6:18 am

No glow of laptops aided latecomers who picked their way through the darkened aisles of Stanford Linear Accelerator’s Panofsky auditorium on Monday. Free from notepads, pens, and computers, audience members understood that it was time to celebrate. The event recognized the successful launch of the Gamma-ray Large Area Space Telescope, or GLAST, on June 11 and its continued smooth progress into orbit. The launch was a culmination of 16 years of hard work, ingenuity, and large-scale collaboration–now crowned by Nolan Gasser’s musical tribute. Filling the room to near capacity, colleagues from around SLAC delighted in the composition for brass quintet, accompanied by a video presentation produced by NASA’s Goddard Space Flight Center.

The nine-minute video took viewers through depictions of humankind’s astronomical legacy, interspersed with footage from GLAST’s own history. A regal melody accompanied the telescope’s blast-off and computer-animated flight. Once in orbit around the earth, the cube-shaped detector elicited sounds of awe as it bared itself from the rocket’s sheaths and, bird-like, began to unfold its own long solar panels.

Composed to celebrate the science of the GLAST mission, the GLAST Prelude awaits a further installment in the form of a symphony.

SLAC director Persis Drell lauded the score as “classy” and confessed that she had never before been involved with an experiment “that inspired music of any sort, ever.” Dubbing the launch successful and a huge milestone she remarked, “It’s very magical to think something you contributed to is there staring at the heavens, scanning for cataclysmic events and looking for gamma rays.”

But whatever scientific adrenaline that had been coursing through the collaboration’s veins for days had been fired by fears that were also very real. As Drell admitted, it was “terrifying [to take] an instrument people have worked on for years and put it on a bomb.” She continued: “Experiments are scary but very few experiments go through the singularity of a launch. It’s very nice to be on the other side.” It was the continued presence of this trepidation in the room that allowed her reassurance to hit a waggish note: “I promise that it’s in the night sky if you know where to look…right, guys?”

Peter Michelson, principal investigator for the Large-Area Telescope, the primary instrument on GLAST, took over to briefly review the project’s history, “vibrant international team,” and current impact. “The lab is working in space and it’s a joy to see,” he announced. Showcasing a slide of headlines clipped from a copious collection of global newspapers, he declared, “the world has noticed as well.”

Next came remarks from NASA Project Scientist for GLAST Steve Ritz, who applauded the mission’s teamwork and the past week’s relative quiet. “It’s the technical issues that you don’t hear about that testify to the great job that everyone is doing,” he said. Noting the brilliance and creativity of those involved, he continued, “The fact that things have gone so swimmingly is really a testament to that.”

NASA Program Manager for GLAST Kevin Grady addressed the assembly through a telecom connection and, like Drell, seemed unable to fully revel in the success without recalling other harrowing impressions. Speaking of the last few years’ unexpected challenges, he said, “as it turned out, we had a lot more opportunities to excel…This spacecraft has put a little more gray hair in me.”

Following the celebratory talks, the audience spilled out into a foyer filled with GLAST souvenirs: full-color booklets, stickers, graph paper sticky pads, collapsible 3-D paper sculptures, and pin-up renderings of the telescope.

Outside, attendees enjoyed a sunny lawn party complete with rocket-shaped popsicles and a space-themed soundtrack including David Bowie’s Space Oddity. Colleagues shared personal congratulations, pondered blown-up images of team members and rocket loading stages, and talked about the exciting science to come.

Photos by Calla Cofield

Zoe Macintosh

No Comments »

What do the DAMA dark matter results mean?

July 1, 2008 | 6:35 pm

Ever since it first released results, the DAMA collaboration has attracted controversy. We reported (story 1, story 2) on the latest result issued by the collaboration recently, but more people are starting to interpret the findings.

The Resonaances blog, by the theory group at CERN, includes some analysis which points out that DAMA might be seeing low-mass dark matter particles–lower than can be seen in other experiments such as those of XENON collaboration, which at first glance seem to contradict the DAMA result.

An experiment called CRESST, also housed in the Gran Sasso laboratory in Italy is sensitive to even lower mass particles than DAMA so it should provide some kind of resolution to this debate if it is able to collect enough data. Otherwise, we might be waiting for CRESST’s successor, EURECA, or one of the many other dark matter detection experiments in progress and in planning.

David Harris

No Comments »

The LHC as a massive grid computer

June 30, 2008 | 7:26 am

From one angle the Large Hadron Collider is a particle collider; but from another, it’s a massive grid computer with the collider as its CPU, according to a rich and highly readable overview posted by Tim O’Brien on the O’Reilly Media Web site:

When the LHC is turned on, it will be more than just a 27-km wide particle accelerator buried 100m deep in Geneva colliding protons. When the LHC is running it will be colliding millions of protons per second, and all of this data will need to be captured and processed by a world-wide grid of computing resources. Correction, by a massively awe-inspiring and mind-numbingly vast array of computing resources grouped into various tiers so large that it is measured in units like Petabytes and MSI2K.

What’s a MSI2K?

“Mega SPECint 2000″. SPECint 2000 is a standard measure of the power of a CPU. For an in depth explanation see Wikipedia. If we assume a 2 x 3.0 GHz Xeon CPU is 2.3 KSI2K, then it would take about 430 of those CPUs to equal 1 MSI2K. 4.6 MSI2K is going to involve thousands of CPUs dedicated to data extraction and analysis.

Surprisingly, the main analysis package used for the collider at CERN, the European particle physics lab, is 10 years old and freely available under an open-source license, O’Brien says. He digs into the analysis software and the multiple tiers of computing, scattered among more than 100 data centers around the world, that will process about two Gigabytes of data every 10 seconds from the LHC.

Special bonus:  O’Brien interviews Brian Cox, a physicist at the University of Manchester and one of the most articulate explainers of the LHC, its physics and, in this case, its computing; download the audio and read a transcript here.  Cox’s talk at the March 2008 TED conference is also worth a look.

Glennda Chui

No Comments »

Diploma mill proprietors plead guilty

June 28, 2008 | 8:45 pm

In April 2006, symmetry published an article by George Gollin, professor of physics at the University of Illinois at Urbana-Champaign, about the problem of diploma mills: unaccredited organizations that sell fake university qualifications, usually for a few thousand dollars each.

A story in Sunday’s New York Times discusses how the proprietors and six employees of one of the largest diploma mill cartels have plead guilty to charges of mail and wire fraud, and will be sentenced on Wednesday.

In 2006, Gollin wrote of receiving threats and attempts to convince him to travel to Liberia where he suspected an ambush was planned. He began to work with the US Secret Service on helping expose the those who were selling an estimated 200,000 fake degrees per year.

The Times reports that the diploma mills brought in over $7 million through a network of 121 fictitious universities and false diplomas from real universities.

In Gollin’s piece for symmetry, he commented:

Some of the hazards posed by diploma mills are obvious: cars designed by untrained engineers, children treated by fake physicians, criminals with bogus immigration documents. But the damage is even larger. Liberia needs doctors and engineers and teachers, who can attend foreign graduate programs and return home to help their country. Instead, American diploma mill operators have so thoroughly corrupted the Liberian system of university accreditation that experts in foreign higher education now are sometimes unwilling to recognize a legitimate degree from any Liberian university, including the University of Liberia, which is fighting to rescue its reputation.

Meanwhile, officials from another African country now appear to be cooperating with another diploma mill consortium in the hijacking of their country’s higher education system. The education system of an entire continent could be threatened. It is a problem that demands our attention.

It seems that his call has been heard, with a significant victory against the diploma mills now secured.

David Harris

No Comments »

US House and Senate pass bill with more science funding

June 27, 2008 | 10:49 am

Last night, the US Senate voted to approve an emergency funding bill including $62.5 million for the Department of Energy’s Office of Science. The bill passed by a vote of 92-6 and had previously passed the House by a large majority. (See the coverage of the Kane Country Chronicle, local to Fermilab, here.) The White House has previously indicated that it would sign this funding bill.

The funding comes with language that directs the DOE to use the funds to first prevent staff reductions. The director of Fermilab, Pier Oddone, this morning wrote that he expects to announce the end of the involuntary layoff program that had been planned.

Update: In response to a comment, here is the language from the House bill (care of AIP’s FYI):

“The amended bill includes an additional $62,500,000 for Science. The Department of Energy is instructed to utilize this funding to eliminate all furloughs and reductions in force which are a direct result of budgetary constraints. Workforce reductions which are a result of completed work or realignment of mission should proceed as planned. This funding is intended to maintain technical expertise and capability at the Office of Science, and may be used for National Laboratory Research and Development including research related to new neutrino initiatives. Funding for research efforts shall not be allocated until the Office of Science has fully funded all personnel requirements.”

David Harris

2 Comments »

SLAC, Lawrence Berkeley Lab, and J-Lab join SCOAP3

June 27, 2008 | 6:26 am

As announced on the SCOAP³ website, three more Department of Energy laboratories have joined the open-access consortium: Stanford Linear Accelerator Center, Lawrence Berkeley National Laboratory, and Jefferson Lab. They join four other DOE labs–Argonne, Pacific Northwest National Lab, Los Alamos, and Fermilab–that have pledged to redirect their high-energy physics journal subscription funds to SCOAP³, and thus help make peer-reviewed literature in the field freely available to all.

As reported in an Oct/Nov 07 symmetry article on the initiative:

If it works, no one will have to pay to read most particle physics results. The journals that publish most of the research in the field will be available free online to anyone, anywhere and any time. Money to run the journals—including the cost of having experts review each article before it sees print—would instead come from funding agencies, laboratories and libraries through a consortium called SCOAP³, the Sponsoring Consortium for Open Access Publishing in Particle Physics. This would give journals a stable source of funding while reducing the total cost to libraries and readers.

The proposal is the latest twist in open-access publishing, a worldwide movement whose goal is to pull down barriers to the free flow of information while preserving a system that has kept watch over the integrity of science for nearly 350 years.

Physics, with its long history of openly sharing research results, seems an ideal testing ground for such an idea. Fifty years ago physicists began circulating mimeographed preprints, or unpublished papers, as a way of getting results out more quickly. The mimeograph gave way to the copying machine and the computer; today’s physicists post theories and experimental results on arXiv.org, an Internet clearinghouse set up in 1991 to make it easier for them to swap information. .. As early as 1961, librarians at Stanford Linear Accelerator Center in California started keeping track of circulating preprints, an effort that evolved into SPIRES.

A growing number of other institutions in the United States, as well as organizations in 16 other countries, support this new model of paying publishers directly for the services that the scientific community needs, rather than paying indirectly for these services via subscriptions.

The SLAC Research Library has been a supporter of SCOAP³ in the United States from the beginning, helping to organize and educate libraries in various institutions around the country about the SCOAP³ model and why it fits the HEP community so well. However, it took some work to ensure that the library’s subscription costs were accurately tallied, and furthermore, during this time the entire SLAC library moved to a temporary location while our building is being renovated.

After the dust had settled in our new digs, we were able to take some time to understand the details of our pledge, and ensure that SLAC management understood SCOAP³ and why it would benefit SLAC and the HEP community as a whole. Making it clear that many scientists support SCOAP³, including the major Large Hadron Collider collaborations and HEPAP, the DOE’s High Energy Physics Advisory Panel, was incredibly useful since it helped everyone see how valuable those in the community feel open access to be. I am proud that SLAC was able to make this pledge of support now, and I am excited about the future of SCOAP³.

Travis Brooks

No Comments »

US LHC construction declared formally complete

June 26, 2008 | 12:05 pm

The decade-long project to help build CERN’s LHC accelerator, and the ATLAS and CMS detectors, culminated yesterday (June 25) when Dr. Raymond L. Orbach, Department of Energy under secretary for science and director of the Office of Science, announced the formal completion of the US LHC construction project.

More than 1200 physicists, engineers, and technicians from 90 US universities and national laboratories contributed to this significant milestone, officially known as Critical Decision-4B.

“I would like to congratulate the physicists, engineers and technicians who made the US LHC construction project possible,” Orbach said. “The US has made important contributions to this impressive international effort.”

The DOE and National Science Foundation jointly funded the $531 million project. Close coordination between the funding agencies, US universities and national laboratories resulted in the on-time and on-budget delivery of all US components.

“We are proud to have partnered with the DOE in supporting the US LHC collaborations in this historic international effort,” said Joseph Dehmer, physics division director of the National Science Foundation. “We also note with pride the excellent performance of the construction project, and we look forward to the period of scientific discovery that will result.”

The project provided a unique opportunity for the United States to participate in the largest collaborative effort ever attempted in the physical sciences. Fermilab served as the host laboratory for the US CMS and accelerator programs. Brookhaven National Laboratory hosted the US ATLAS project. Scientists from US universities and national laboratories contributed components to all of the ATLAS detector subsystems and the data acquisition system.

“It was extremely important for the projects to be executed correctly,” said Fermilab’s Hugh Montgomery, the associate director for research who oversaw the US LHC program at Fermilab. “I know from conversations with our international colleagues on the accelerator, ATLAS and CMS that the US contributions have been vital to the overall efforts.”

The accelerator portion of the US LHC construction project included scientists from Brookhaven, Fermilab, and Lawrence Berkeley National Laboratory. Fermilab, in collaboration with CERN and KEK laboratory in Japan, designed and constructed the focusing magnets for the four main LHC experiments. “The project involved design challenges among the most complex and difficult in accelerator science and engineering,” said Fermilab engineer Jim Kerby, who served as US LHC accelerator project manager. “It is gratifying to close the door on our initial contribution to the LHC.”

During the final portion of the CMS construction project, major US contributions included the fabrication and installation of the endcap muon, hadron calorimeter, forward pixel, and silicon tracker subsystems. US CMS scientists also collaborated on the electromagnetic calorimeter, trigger, and data acquisition systems. “We followed a soup-to-nuts strategy and completed nearly whole subsystems at a time,” said Fermilab physicist Dan Green, who served as US CMS project manager during the construction phase.

The forward pixel detector, the subsystem that allows physicists to precisely reconstruct particle collisions, is one of the last major components that the United States built for CMS. Experts from Fermilab and US universities worked closely together during a period of two years to develop, assemble, test, and deliver the complex subsystem. “The forward pixel is a first-generation detector of its kind and required a lot of coordination,” said Daniela Bortoletto, a physicist at Purdue University. “The strength of our team allowed us to pull it together in a successful way.”

US LHC scientists now turn their full attention to the research program in preparation for the LHC start-up later this summer.

This story originally appeared in Fermilab Today and SLAC Today.

Read more about the declaration at @brookhaven TODAY.

Elizabeth Clements

No Comments »

A quick, easy way to grill candidates on science policy

June 26, 2008 | 6:50 am

Where do the candidates on your November ballot stand when it comes to support for basic research, climate change, energy and health policies, education, and other issues involving science and technology?   Sixteen prominent science and engineering organizations, including the American Association for the Advancement of Science, the American Physical Society, IEEE, and the American Institute of Physics, have developed a questionnaire and sent it to every Congressional candidate across the nation.  And they’ve made it easy for you to do the same. Just go to the Science and Engineers for America Web site, type in your zip code to see who’s running in your area, and shoot them the questions in an email.

The questions:

1. Innovation. Science and technology have been responsible for half of the growth of the American economy since World War II. But several recent reports question America’s continued leadership in these vital areas. What policies would you support to ensure that America remains the world leader in innovation?
2. Climate Change. The Earth’s climate is changing and there is concern about the potentially adverse effects of these changes on life on the planet. What is your position on the following measures that have been proposed to address global climate change—a cap-and-trade system, a carbon tax, increased fuel-economy standards, and research? Are there other policies you would support?
3. Energy. Many scientists and policymakers say energy security and sustainability are major problems facing the United States this century. What policies would you support to meet the demand for energy while ensuring an economically and environmentally sustainable future?
4. Education.A comparison of 15-year-olds in 30 wealthy nations found that average science scores among U.S. students ranked 17th, while average U.S. math scores ranked 24th. What role do you think the federal government should play in preparing K-12 students for the science and technology driven 21st Century?
5. Water. Thirty-nine states expect some level of water shortage over the next decade, and scientific studies suggest that a majority of our water resources are at risk. What policies would you support to meet demand for water resources?
6. Research. For many years, Congress has recognized the importance of science and engineering research to realizing our national goals. Given that the next Congress will likely face spending constraints, what priority would you give to investment in basic research in upcoming budgets?
7. Health. Americans are increasingly concerned with the cost, quality, and availability of health care. How do you see science, research, and technology contributing to improved health and quality of life?

Candidates’ responses will be posted on the SHARP Network, a wiki hosted by Science and Engineers for America that tracks where elected officials and candidates stand on science policy issues. SEA has been urging scientists and engineers to run for public office at all levels, from local school boards to the House, Senate, and, heck, even the presidency, although it looks like they’ll have to wait a few years for that one.  See this commentary by executive director Lesley Stone in the March/April 08 issue of symmetry.

Glennda Chui

1 Comment »