Gamma-ray burst hits highest energy yet

September 11, 2009 | 3:58 pm

This story first appeared in SLAC Today on September 11, 2009.

For the second time in as many years, a Large Area Telescope collaboration meeting was punctuated by a stellar firework. Last week’s meeting, which ran from August 29 through September 4 at SLAC National Accelerator Laboratory, was briefly interrupted on Wednesday when the LAT, the main instrument onboard the Fermi Gamma-ray Space Telescope, recorded a large gamma-ray burst.

Although the Gamma-ray Burst Monitor, the other instrument aboard the Fermi telescope, sees gamma-ray bursts almost daily, the LAT detects far fewer because it views only about a sixth of the sky at any given time and detects only the bursts that emit the highest-energy gamma rays. Including last week’s burst, the LAT total now stands at ten.

When the alert came in last week notifying collaboration members of the possibility of a newly detected burst, the researchers leapt to action, alerting astronomers around the world so that they too could turn their instruments toward it. At the same time, the LAT automatically stopped its regular scan of the sky to continue recording the burst.

“We knew this was likely to be an exciting one—it was immediately clear that it was a very big burst,” said SLAC astrophysicist and LAT collaboration member Jim Chiang.

Using additional data collected that afternoon, researchers determined that the burst included the highest energy gamma-ray so far measured from a gamma-ray burst: 33 GeV.

Roger Blandford, director of the Kavli Institute for Particle Astrophysics and Astrophysics, said that three main scientific messages can be gathered from this type of burst. “First, when you see high-energy gamma rays, it means the source must be rushing toward us with high speed. Second, from these gamma rays we’ve come to believe that most bursts are associated with the birth of a black hole in a supernova explosion.” And third, Blandford said, observations are showing that short- and long-duration bursts, which were previously considered to be different in some fundamental way, from our perspective are looking increasingly similar. But that last understanding is still a work in progress, he said.

“The LAT is a superb instrument that keeps on giving,” said Blandford. “It’s outperformed our highest expectations in almost all areas. Everyone who’s associated should take pride.”

Kelen Tuttle

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Visiting a physics conference in Japan

September 11, 2009 | 11:02 am

An international group of physicists-many of them young-met in Kobe, Japan, last week to discuss the experiments and theories of the energy frontier.

The annual Physics in Collision conference began in the United States in Blacksburg, Va., in 1981. For 29 years, the conference has given particle physicists a chance to present their work and discuss the with one another what it means.

In this video, one of the hosts of PIC 2009 and a future host of PIC 2010 offer a flavor of what an international physics conference is all about.

Kathryn Grim

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Forget it Rhonda: Help, help me Einstein

September 10, 2009 | 10:51 am

“….. Help me Einstein!

Help, help me Einstein!

Spot the gravity wave.”

Aerial view of the LIGO interferometer at the Hanford, WA., site. Courtesy of Caltech.

Aerial view of the LIGO interferometer at the Hanford, WA., site. Courtesy of Caltech.

A group of summer students working on the Laser Interferometric Gravitational-Wave Observatory, or LIGO, project at the California Institute of Technology created a medley of songs on YouTube to explain their research.

The handful of tunes, set to the music of popular classics including “The Time Warp”, “Help Me, Rhonda,” and “California Dreamin’”, offer an alternative way to learn about the science. The lyrics are educational but the singing isn’t exactly out of this world.

LIGO is operated by Caltech and MIT, and is a collaboration of more than 600 scientists working towards detecting and measuring cosmic gravitational waves. LIGO, which has installations in Hanford, Washington, and Livingston, Louisiana, is part of a planned worldwide network of gravitational wave observatories. Scientists believe these waves could carry clues to the nature of gravity.

A simulation of a gravitational wave. Courtesy of Caltech.

A simulation of a gravitational wave. Courtesy of Caltech.

These waves are ripples in the fabric of space and time caused by energy called gravitational radiation getting pushed through the universe by a violent event such as a supernova explosion. The waves have only indirectly been detected.

LIGO began operation in 2001. If you would like to keep up on LIGO’s progress, you can peruse the experiment’s blog here.

Tona Kunz

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Calming the wakefield

September 9, 2009 | 2:56 pm

This story first appeared in International Science Grid This Week on September 9, 2009.

A snapshot of a simulation of the wakefield generated by a particle bunch moving through a series of ILC cavities, from three different perspectives. The colors represent the magnitude of the fields, with warmer colors representing the strongest fields.

A snapshot of a simulation of the wakefield generated by a particle bunch moving through a series of ILC cavities, from three different perspectives. The colors represent the magnitude of the fields, with warmer colors representing the strongest fields.

For the International Linear Collider to run at maximum performance, each of its 27,000 cavities must be designed as precisely as possible.

It is very time consuming and costly, however, to produce physical prototypes, so researchers at SLAC National Accelerator Laboratory decided to use a supercomputer to create and test virtual prototypes of the cavities.

The ILC, which is in its design phase, will use superconducting cavities to accelerate electrons and their antimatter partners, positrons, to nearly the speed of light before colliding them. By studying these collisions, researchers will be able to probe more deeply into the subatomic world.

As particle bunches travel through the accelerator cavities, they produce electromagnetic wakes behind them, much like the waves left behind as a speedboat races across the water.

These wakefields interfere with bunches that follow, causing some particles to stray off course, degrading the electron beam’s quality. The wakefields also produce heat that can damage cavities and cause the accelerator to malfunction.

The more powerful the beam, the stronger the wakefield. And with expected collision energies of around 500 billion electronvolts, the ILC definitely has the potential to produce strong wakefields.

“From our simulations, we can measure the wakefield and modify the cavity’s design until it is within a certain limit,” said SLAC researcher Cho Ng. “By doing this, you can bypass the process of developing a prototype several times and reduce cost.”

The first step in producing a simulation is to create a computerized mesh representation of the cavities. Then the researchers must simulate a particle beam going through the cavities, including a simulation of how the individual particles behave. From this, they can calculate the strength of the wakefields created and tweak the cavity design to minimize the effect.

The SLAC group’s simulations revealed that ILC designers can considerably reduce wakefields by using damping mechanisms–devices placed inside and outside the cavities that absorb lingering electromagnetic wakes.

This isn’t the kind of simulation they can simply run on their desktop, however. Each simulation requires the processing of about 10 terabytes of data, said SLAC researcher Lie-Quan Lee.

To generate the simulations, the SLAC group has been allotted 12.5 million processor hours on Jaguar, a U.S. Department of Energy supercomputer at Oak Ridge National Laboratory that can perform up to 1.64 quadrillion operations per second. Using Jaguar, each simulation takes about a week to complete and is much less expensive than producing physical prototypes.

“We use our simulations to make sure the ILC will operate according to design,” Ng said. “We don’t want to come back later with a cavity that doesn’t work and have to redesign it because that is very costly.”

by Amelia Williamson

Guest author

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Superconducting tech funding to benefit US industry

September 9, 2009 | 11:52 am

Fermilab will use Recovery Act funds to expand its superconducting radio frequency test facility and make cryomodules to construct a prototype accelerator.

Fermilab will use Recovery Act funds to expand its superconducting radio frequency test facility and make cryomodules to construct a prototype accelerator.

In August, the US Department of Energy announced that the American Recovery and Reinvestment Act will provide Fermilab with $52.7 million to test and develop superconducting radio-frequency (SRF) cavities, a key technology for next-generation accelerators and the future of particle physics. The funds provide a significant boost to the SRF program at Fermilab, allowing the laboratory to expand its test facilities and strengthen American manufacturing capabilities.

“The Recovery Act speeds up what we were doing and allows us to do things we wouldn’t be able to do otherwise,” said Bob Kephart, director for Fermilab’s International Linear Collider program.

Fermilab will invest roughly 80 percent of the $52.7 million in stimulus funds in US industry.

“There has been lots of progress, but at this time, no US vendor is yet qualified to produce accelerator cavities of the quality needed for the proposed Project X or ILC,” Kephart said. “The Recovery Act will advance funding to allow US industry to develop the capabilities they need to become competitive manufacturers of SRF components.”

Plans call for Fermilab to purchase around 40 SRF cavities and other cryomodule components from US vendors, helping US industry develop the capabilities they need to become a competitive manufacturers of SRF components.

Fermilab will distribute a portion of the funds to upgrade existing SRF infrastructure at Argonne National Laboratory, Thomas Jefferson National Accelerator Facility, and SLAC National Accelerator Laboratory.

At Fermilab, in addition to ordering cavities, the stimulus funds will also go toward building a cryogenic plant at the New Muon Laboratory to cool cryomodules to minus 271 degrees Celsius. Other items Fermilab will purchase include a high-temperature oven and additional systems to test the capability and quality of SRF cavities. All of this infrastructure will enable Fermilab to evolve into one of the most advanced SRF R&D centers in the world.

SRF cavities have become the technology of choice for many proposed accelerator-based projects, including the proposed Project X, International Linear Collider, and a muon collider, because of their highly efficient ability to accelerate beams of particles. Physicists expect that SRF technology has potential applications in medicine, energy and material science.

Visit Fermilab’s Recovery Act Web site.

This story was originally published in Fermilab Today Sept. 4.

Elizabeth Clements

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International Linear Collider detector designs validated

September 8, 2009 | 6:22 pm

This story first appeared in SLAC Today on September 8, 2009.

Two of the three detector design concepts for the proposed next linear collider have been validated by the International Detector Advisory Group, and their conclusions endorsed by the International Linear Collider Steering Committee. These detector designs had been presented to the IDAG earlier this year in Letters of Intent, which outlined the type of detectors the researchers wish to build and the physics performance to be expected from each.

“This was a challenging and time consuming process,” said physicist John Jaros, who co-heads SLAC National Accelerator Laboratory’s Linear Collider Detector department with Marty Breidenbach and also serves as a co-spokesperson for the Silicon Detector, one of the two validated design concepts. “All of these efforts ran on heroes who accomplished a lot with relatively little in the way of resources.”

The validation process ensured that the proposed detectors can do justice to the physics that would be undertaken with the next linear collider, and that the proposing group has the ability and resources to complete a full detector design. Researchers working on the two validated detector concepts will now begin creating much more detailed designs.

SLAC plays a significant role in the design of the Silicon Detector. Smaller than the other proposed detectors, the SiD is built around a compact silicon tracker, highly pixilated electromagnetic and hadronic calorimeters, and a high field magnet. Together, these components would precisely track and measure particles streaming from the collision point.

“The collaboration was pleased with the quality of our submission-it’s good work and a real step forward,” said Jaros. “We’re also very appreciative of SLAC for making computing resources available to complete the validation process.”

Also validated was the International Large Detector. Designed by a group of mostly European and Asian collaborators, the ILD is an amalgamation of two former detector designs, the so-called “LDC” and the “GLD,” both of which were based on a large gaseous tracker.

The SiD and ILD collaborations are now ramping up efforts to complete the detailed baseline detector designs. These designs will be included in the next linear collider technical proposal, planned for completion in 2012.

“There’s an awful lot to get done before then, including the proof-of-principle R&D that will demonstrate that our ideas will actually work,” said Jaros. “But I have no doubt that we can succeed.”

Kelen Tuttle

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Stimulus money for research into the smallest matter has large impact

September 8, 2009 | 12:29 pm

Want to know where some of your stimulus dollars are going? And if the spending is worthwhile?

An interesting 3-minute news report highlights one use of stimulus funding by the particle physics community and explains that the money is creating non-laboratory jobs, expanding our knowledge of the world and building the path to technological competitiveness.

The report gives a quick overview of Jefferson National Laboratories plans to use $65 million in American Recovery and Reinvestment Act funds to upgrade its electron beam.

The project broke ground in April and is pumping millions of dollars into local construction and service industries as well as high-tech manufacturing across the country. American Recovery and Reinvestment Act funding accounts for about $65 million of the $310 million project.

The news report gives a nice overview of the work so far and explains how the electron beam work could explain more about the matter that makes up us and the world around us as well as create spin offs that effect your quality of life. The same type of research used in the electron beam experiment launched a new form of gamma ray imaging that makes mammograms less uncomfortable and provides better images of cancer tumors, according to the Newport News.

Jefferson Lab is a world-leading nuclear physics research laboratory devoted to the study of the building blocks of matter –quarks and gluons. The upgrade will double the energy of the lab’s electron beam from 6 billion electronvolts (GeV) to 12 GeV and enable scientists to address one of the great mysteries of modern physics: Why are there no single quarks?

If you want to know more about quarks, JLab produced two videos in 2000 explaining the value of researching them. You can view part one here and part two here.

Tona Kunz

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LHC update: September 4, 2009

September 4, 2009 | 1:40 pm

The latest update on the Large Hadron Collider from the CERN Bulletin:

On 26 August, the first two fully tested crates for the new quench protection system (QPS) were installed in Sector 1-2. These are the first of 436 crates that will be installed around the ring. The two crates include detectors for both the enhanced busbar protection and the symmetric quench protection (more details).

To test the crates before installation, a dedicated test bed has been created, capable of simulating all the conditions in the LHC, from a symmetric quench to an increase in busbar resistance. The teams are working two shifts a day, including weekends, to test the new crates. Two more test benches are also being built to increase the production rate. The whole task is on target for completion in mid October.

Another important new task for the QPS team is to try and speed up the energy extraction from the magnets. The quicker the energy can be extracted the lower the risk of dangerously high temperatures should a quench occur.

The time constant for the dipoles will be halved to about 50 seconds. The decision to run at 3.5 TeV, and therefore with lower current in the magnets, has in fact made this task relatively straightforward. By switching two of the three ‘dump’ resistors into a series circuit instead of having all three resistors in parallel, allows the energy to be converted to heat much faster. This modification is currently ongoing and takes only a few hours for each of the 16 extraction systems. In the quadrupole circuits the task is more complex. Reducing the time constant to the desired 10 seconds, from a previous 35 seconds, requires adding extra resistors.

Another advantage of the new QPS system is that it will allow accurate resistance measurements to be taken remotely. Over the past 3 months the QPS team has checked nearly 40 000 individual resistance measurements by hand, and in the process clocked up an impressive 500 km walking around the ring. A small testing device is currently being developed to automate this process using the new QPS system. This will save a huge amount of time and effort for the next rounds of interventions–for example when the LHC energy is increased.

In Sector 8-1 the flexible hose, which caused the helium leak into the insulation vacuum, has now been replaced and the sector is now being cooled down again.

Work to install the ‘pressure release springs’ is progressing well, with only one sector remaining–Sector 3-4.

In Sector 6-7 repairs are being made to fix the short-circuit to ground, which occurred in the dipole circuit on 20 August (see previous update).

Guest author

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The PAMELA spacecraft's view of the Van Allen radiation belts

September 4, 2009 | 7:15 am

Two rings of highly energetic charged particles encircle the earth, trapped in its magnetic field. The inner ring, made up mostly of protons, hovers about 500 miles above our heads. The outer ring is mostly made up of electrons.

These radiation belts are named for astrophysicist James Van Allen, who first discovered them. Though the Van Allen belts are invisible to the naked eye, an instrument called PAMELA gives physicists an idea what they would look like.

The Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics, or PAMELA, telescope was launched in June 2006 from Kazakhstan in part to study the radiation belts. Its goals are to search for dark matter, baryon asymmetry, and the source of cosmic rays. Marco Casolino, a researcher at the National Institute of Nuclear Physics in Rome, described the instrument in a talk at the Physics in Collision conference in Kobe, Japan, this week.

To illustrate its capabilities, he showed the following fascinating animation:

PAMELA’s view of the Van Allen belts

The video gives a tour of the Van Allen belts, as measured with PAMELA spectrometer on board Russian satellite Resurs-DK1. Measurements are between 600 and 370 km and are shown to scale.

Kathryn Grim

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Turkey plans an accelerator center

September 3, 2009 | 1:14 pm

The proposed Turkish Accelerator Center will include a set of accelerators and storage rings that be used in various combinations.

Over the last ten years, Turkish physicists have been working diligently to build a national accelerator center, which would serve as a core science facility and offer increased opportunities for Turkish students. It would be the first accelerator facility in the country, and only the second in the Middle East.

After much planning, excitement is building over the construction of the first phase of the project, a testing and research facility called the Turkish Accelerator and Radiation Laboratory at Ankara, or TARLA for short. Scheduled to be completed in 2012, it will be an Infrared Free Electron Laser, capable of producing an intense laser beam of infrared light for research in a wide variety of sciences ranging from physics to chemistry to biology and medicine.

As the construction of TARLA gets underway, three Turkish physicists have been touring three US national laboratories–SLAC National Accelerator Laboratory, Thomas Jefferson National Accelerator Facility, and Argonne National Laboratory–to learn more about specific types of accelerator technology and experiments.

The visits represent more than simply a technical exchange. While at SLAC, the physicists raised the possibility of future collaborations.

“The main reason we are here is to be able to establish a collaboration between SLAC and our project so we can have an exchange of students and scientists,” said Suat Ozkorucuklu, an experimental high-energy physicist from Suleyman Demirel University. “We are looking forward to having our students, young scientists, be trained and educated, and maybe work towards their degrees at SLAC.”

TAC represents the second accelerator center in the Middle East. The first, SESAME, is a synchrotron light source, built in Jordan from recycled portions of accelerators from French, German, Swiss, UK, and US labs, including SLAC. Scientists from Bahrain, Cyprus, Egypt, Iran, Israel, Jordan, Pakistan, Palestine Authority, and Turkey all collaborate on the SESAME project, but Turkey has started to look at its national needs for an accelerator center. TAC would be a much larger facility built in Turkey’s backyard, making the study of particle physics much more accessible. The center would also allow for great strides to be made in technology.

“Countries trying to develop and become a big country, they need these types of technologies,” Ozkorucuklu said. He spent two days touring SLAC with Omar Yavas of Ankara University, the director of the TAC project, and Pervin Arikan of Gazi University. The three looked closely at the SPEAR storage ring and the experiments it can conduct as well as at the LCLS, an X-ray laser that will study structure and dynamics on a molecular scale.

The Turkish Accelerator Center was first proposed in 2000 by a group of scientists from Ankara and Gazi University. Nearly 100 scientists from 10 universities across Turkey are collaborating on its development with Ankara University, the future site of the project, at the helm.

The design plan for the TAC is to have a combination of an electron linear accelerator and a positron storage ring that could be used individually or as a unit for a wide range of experiments. This would be the second combination complex build in recent years; the Beijing Electron Positron Collider also combines a particle collider and an X-ray light source.

The physicists said that in the “big dream,” TARLA would be followed by four more facilities at the site.

A charm factory would allow physicists to study particles containing charm and anticharm quarks, offering insight into the balance of matter and antimatter produced during the formation of our universe. A SASE FEL, or Self-Amplified Stimulated-Emission Free Electron Laser, would use radiated X-ray light traveling through a long undulator along with an electron beam to further amplify the laser light, similar to the production of the X-rays in LCLS at SLAC. A third generation light source would accelerate positrons around a ring to produce X-rays for experimentation. The final piece, the proton accelerator facility, would be used for neutron scattering experiments.

The light sources will be used for research in all areas of science, including engineering and industrial sciences, cancer therapies, materials science, semiconductor development, and biotechnological research.

Ozkorucuklu said that the developing center will not only advance Turkey’s study of particle physics, but also other sciences and technologies: “We have to have this kind of physics to be able to go into other areas of research–material science, health, engineering, electronics, software systems, etc. Once you have a facility this big you have to develop new technologies and new processes to be able to run your machine and run your facility.”

Construction on TARLA will start next month. In the meantime, the planning committee is writing a technical design report for the next steps. Once TARLA is up and running, the TAC committee will ask the Turkish government for funds to start building the next project.

Should the “big dream” come true, Ozkorucuklu said, all five projects could be completed in the next 25 years.

This research facility represents an important step forward for Turkey, Ozkorucuklu said. “All the developed countries around the world have this type of technology,” he said, and acquiring this type of technology helps countries develop. Turkey recently applied for membership in the European Union and CERN, the European particle physics lab. The visiting physicists said they think having an accelerator facility will greatly help their applications to both organizations.

Ozkorucuklu said he envisions TAC as a place where “lots of people from all branches of science come together, so it becomes a center of excellence in science.” He said the coordinators expect more than 100 scientists to use TARLA when it opens, with more likely in the future.

Once TARLA is completed, Turkey will be able to train students in accelerator research for the first time. “At this moment they have to go abroad to get this kind of knowledge,” Ozkorucuklu said. “But if we can have it in Turkey, it will be easier for us and easier for them.”

Turkey’s timing could not be better. President Barack Obama recently expressed interest in improving science and technology in the Muslim world through outreach programs.

Tangible plans have yet to be made by the US government, but Turkish scientists may yet receive the additional resources and collaboration they seek to make their “big dreams” a reality.

by Lauren Knoche

Symmetry Intern

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