martedì 20 ottobre 2009

CERN (LHC): ATLAS Live, a new browser showing the 1000 most recent events for each stream, is now online.

ATLAS Live, a new browser showing the 1000 most recent events for each stream, is now online. It’s perfect for collaborators all over the world who want to check up on what’s going on underground at any time of day or night. Whether you be in your pyjamas rubbing your eyes before your 6 a.m. run in Ferney, or dressed to impress on your way to a concert hall in Paris, your window onto the detector is always open for you to sneak a peek.In fact, the ALTAS Live in question – developed by former ATLAS member Zdenek Maxa – is one of three ventures going by the same name. Ultimately, the information from this page will feed into another ATLAS Live, being developed by Manuela Cirilli and Kathy Pommes, which will also feature items like message boards and updates on ATLAS run status. The event display browser includes all the different Trigger streams and displays 20 Atlantis images per page, which users can scroll back and forth through. If they spot something of interest, they can download the image, or download the original JiveXML and corresponding VP1 input file for each selected event. They can also directly launch Atlantis on any given event, and then further interrogate it by zooming in, picking on data, implementing cuts and adjusting the view windows, to best highlight what they are interested in. “We focused a little bit more on the Atlantis side [rather than VP1] because Atlantis is a java application, so it can use this web start feature and doesn’t need to know what machine you’re running on,” explains Online Event Display Coordinator, Sebastian Böser. “This is basically the side of it that we have for the physicists. So they browse through these events and they say, ‘Wait a second, this looks really interesting, I want to go and see this in another projection.’” The display works on a rolling system, so as each new image comes in, the 1000th image drops off the end. Events make it on screen with around a ten second lag time. Right now, while there are only cosmics to be seen, 1000 events take place over a timescale of a few hours. Once there are collisions, 1000 events will be notched up in around ten minutes. At the bottom of the ATLAS Live page, there is also a link to a ‘latest event’ page. “We were thinking of all those people who might want to put up monitors in their universities showing the latest from the detector,” explains Sebastian. After selecting a stream, the image refreshes itself every five seconds, and all the user needs to do is point their web browser at that page and let it roll. The system has been up for six weeks or so already, and Sebastian urges everyone to check it out now and get familiar with it ahead of beam. In practical terms, this will allow the online data preparation group to monitor the load on the server, and iron out any problems that may arise. Combined cosmic running has already begun – go and take a look at what your detector can see!
Ceri Perkins

mercoledì 14 ottobre 2009

Search for Future Influence From Large Hadron Collider (LHC) at CERN.

More than a year after an explosion of sparks, soot and frigid helium shut it down, the world’s biggest and most expensive physics experiment, known as the Large Hadron Collider, is poised to start up again. In December, if all goes well, protons will start smashing together in an underground racetrack outside Geneva in a search for forces and particles that reigned during the first trillionth of a second of the Big Bang.
Then it will be time to test one of the most bizarre and revolutionary theories in science. I’m not talking about extra dimensions of space-time, dark matter or even black holes that eat the Earth. No, I’m talking about the notion that the troubled collider is being sabotaged by its own future. A pair of otherwise distinguished physicists have suggested that the hypothesized Higgs boson, which physicists hope to produce with the collider, might be so abhorrent to nature that its creation would ripple backward through time and stop the collider before it could make one, like a time traveler who goes back in time to kill his grandfather.
Holger Bech Nielsen, of the Niels Bohr Institute in Copenhagen, and Masao Ninomiya of the Yukawa Institute for Theoretical Physics in Kyoto, Japan, put this idea forward in a series of papers with titles like “Test of Effect From Future in Large Hadron Collider: a Proposal” and “Search for Future Influence From LHC,” posted on the physics Web site in the last year and a half.
According to the so-called Standard Model that rules almost all physics, the Higgs is responsible for imbuing other elementary particles with mass.
“It must be our prediction that all Higgs producing machines shall have bad luck,” Dr. Nielsen said in an e-mail message. In an unpublished essay, Dr. Nielson said of the theory, “Well, one could even almost say that we have a model for God.” It is their guess, he went on, “that He rather hates Higgs particles, and attempts to avoid them.”
This malign influence from the future, they argue, could explain why the United States Superconducting Supercollider, also designed to find the Higgs, was canceled in 1993 after billions of dollars had already been spent, an event so unlikely that Dr. Nielsen calls it an “anti-miracle.”
You might think that the appearance of this theory is further proof that people have had ample time — perhaps too much time — to think about what will come out of the collider, which has been 15 years and $9 billion in the making.
The collider was built by
CERN, the European Organization for Nuclear Research, to accelerate protons to energies of seven trillion electron volts around an 18-mile underground racetrack and then crash them together into primordial fireballs.
For the record, as of the middle of September, CERN engineers hope to begin to collide protons at the so-called injection energy of 450 billion electron volts in December and then ramp up the energy until the protons have 3.5 trillion electron volts of energy apiece and then, after a short Christmas break, real physics can begin.
Dr. Nielsen and Dr. Ninomiya started laying out their case for doom in the spring of 2008. It was later that fall, of course, after the CERN collider was turned on, that a connection between two magnets vaporized, shutting down the collider for more than a year.
Dr. Nielsen called that “a funny thing that could make us to believe in the theory of ours.”
He agreed that skepticism would be in order. After all, most big science projects, including the
Hubble Space Telescope, have gone through a period of seeming jinxed. At CERN, the beat goes on: Last weekend the French police arrested a particle physicist who works on one of the collider experiments, on suspicion of conspiracy with a North African wing of Al Qaeda.
Dr. Nielsen and Dr. Ninomiya have proposed a kind of test: that CERN engage in a game of chance, a “card-drawing” exercise using perhaps a random-number generator, in order to discern bad luck from the future. If the outcome was sufficiently unlikely, say drawing the one spade in a deck with 100 million hearts, the machine would either not run at all, or only at low energies unlikely to find the Higgs.
Sure, it’s crazy, and CERN should not and is not about to mortgage its investment to a coin toss. The theory was greeted on
some blogs with comparisons to Harry Potter. But craziness has a fine history in a physics that talks routinely about cats being dead and alive at the same time and about anti-gravity puffing out the universe.
Niels Bohr, Dr. Nielsen’s late countryman and one of the founders of quantum theory, once told a colleague: “We are all agreed that your theory is crazy. The question that divides us is whether it is crazy enough to have a chance of being correct.”
Dr. Nielsen is well-qualified in this tradition. He is known in physics as one of the founders of string theory and a deep and original thinker, “one of those extremely smart people that is willing to chase crazy ideas pretty far,” in the words of Sean Carroll, a Caltech physicist and author of a coming book about time, “From Eternity to Here.”
Another of Dr. Nielsen’s projects is an effort to show how the universe as we know it, with all its apparent regularity, could arise from pure randomness, a subject he calls “random dynamics.”
Dr. Nielsen admits that he and Dr. Ninomiya’s new theory smacks of time travel, a longtime interest, which has become a respectable research subject in recent years. While it is a paradox to go back in time and kill your grandfather, physicists agree there is no paradox if you go back in time and save him from being hit by a bus. In the case of the Higgs and the collider, it is as if something is going back in time to keep the universe from being hit by a bus. Although just why the Higgs would be a catastrophe is not clear. If we knew, presumably, we wouldn’t be trying to make one.
We always assume that the past influences the future. But that is not necessarily true in the physics of Newton or Einstein. According to physicists, all you really need to know, mathematically, to describe what happens to an apple or the 100 billion galaxies of the universe over all time are the laws that describe how things change and a statement of where things start. The latter are the so-called boundary conditions — the apple five feet over your head, or the Big Bang.
The equations work just as well, Dr. Nielsen and others point out, if the boundary conditions specify a condition in the future (the apple on your head) instead of in the past, as long as the fundamental laws of physics are reversible, which most physicists believe they are.
“For those of us who believe in physics,” Einstein once wrote to a friend, “this separation between past, present and future is only an illusion.”
Kurt Vonnegut’s novel “Sirens of Titan,” all of human history turns out to be reduced to delivering a piece of metal roughly the size and shape of a beer-can opener to an alien marooned on Saturn’s moon so he can repair his spaceship and go home.
Whether the collider has such a noble or humble fate — or any fate at all — remains to be seen. As a Red Sox fan my entire adult life, I feel I know something about jinxes.

lunedì 5 ottobre 2009

Graphite Mimics Iron's Magnetism: New Nanotech Applications.

ScienceDaily (Oct. 5, 2009) — Researchers of Eindhoven University of Technology and the Radboud University Nijmegen in The Netherlands show for the first time why ordinary graphite is a permanent magnet at room temperature. The results are promising for new applications in nanotechnology, such as sensors and detectors. In particular graphite could be a promising candidate for a biosensor material. The results will appear online on 4 October in Nature Physics.
Graphite is a well-known lubricant and forms the basis for pencils. It is a layered compound with a weak interlayer interaction between the individual carbon (graphene) sheets. Hence, this makes graphite a good lubricant.

It is unexpected that graphite is ferromagnetic. The researchers Jiri Cervenka and Kees Flipse (Eindhoven University of Technology) and Mikhail Katsnelson (Radboud University Nijmegen) demonstrated direct evidence for ferromagnetic order and explain the underlying mechanism. In graphite well ordered areas of carbon atoms are separated by 2 nanometer wide boundaries of defects. The electrons in the defect regions (the red/yellow area in picture 1) behave differently compared to the ordered areas (blue in picture 1), showing similarities with the electron behaviour of ferromagnetic materials like iron and cobalt.

Debate settled:
The researchers found that the grain boundary regions in the individual carbon sheets are magnetically coupled, forming 2-dimensional networks (picture 2). This interlayer coupling was found to explain the permanent magnetic behaviour of graphite. The researchers also show experimental evidence for excluding magnetic impurities to be the origin of ferromagnetism, ending ten years of debate.

Carbon in spintronics:
Surprisingly, a material containing only carbon atoms can be a weak ferro magnet. This opens new routes for spintronics in carbon-based materials. Spins can travel over relative long distances without spin-flip scattering and they can be flipped by small magnetic fields. Both are important for applications in spintronics. Carbon is biocompatible and the explored magnetic behaviour is therefore particularly promising for the development of biosensors.
The research was funded by Nanoned and FOM.
Journal reference:
Jiri Cervenka, Mikhail Katsnelson and Kees Flipse. Room-temperature ferromagnetism in graphite driven by 2D networks of point defects. Nature Physics, October 4, 2009 DOI:
Adapted from materials provided by Eindhoven University of Technology, via EurekAlert!, a service of AAAS.

giovedì 1 ottobre 2009

Step Forward For Nanotechnology: Controlled Movement Of Molecules.


ScienceDaily (Oct. 1, 2009) — Scientists in the United Kingdom are reporting an advance toward overcoming one of the key challenges in nanotechnology: Getting molecules to move quickly in a desired direction without help from outside forces.
Their achievement has broad implications, the scientists say, raising the possibility of coaxing cells to move and grow in specific directions to treat diseases. It also could speed development of some long-awaited nanotech innovations. They include self-healing structures that naturally repair tears in their surface and devices that deliver medication to diseased while sparing healthy tissue.
The study is scheduled for the October issue of ACS Nano, a monthly journal.
Mark Geoghegan and colleagues note long-standing efforts to produce directed, controlled movement of individual molecules in the nano world, where objects are about 1/50,000ththe width of a human hair. The main solutions so far have involved use of expensive, complex machines to move the molecules and they have been only partially successful, the scientists say.
The scientists used a special surface with hydrophobic (water repelling) and hydrophilic (water-attracting) sections. The region between the two sections produced a so-called "energy gradient" which can move tiny objects much like a conveyor belt. In lab studies, the scientists showed that plastic nanoparticles (polymer molecules) moved quickly and in a specific direction on this surface. "This could have implications in many technologies such as coaxing cells to move and grow in given directions, which could have major implications for the treatment of paralysis," the scientists said.
Journal reference:
Burgos et al. Directed Single Molecule Diffusion Triggered by Surface Energy Gradients. ACS Nano, 2009; 090923111502009 DOI:
Adapted from materials provided by American Chemical Society, via EurekAlert!, a service of AAAS.

Spallation Neutron Source First Of Its Kind To Reach Megawatt Power.

ScienceDaily (Oct. 1, 2009) — The Department of Energy's Spallation Neutron Source (SNS), already the world's most powerful facility for pulsed neutron scattering science, is now the first pulsed spallation neutron source to break the one-megawatt barrier.
"Advances in the materials sciences are fundamental to the development of clean and sustainable energy technologies. In reaching this milestone of operating power, the Spallation Neutron Source is providing scientists with an unmatched resource for unlocking the secrets of materials at the molecular level," said Dr. William F. Brinkman, Director of DOE's Office of Science.
SNS operators at DOE's Oak Ridge National Laboratory pushed the controls past the megawatt mark on September 18 as the SNS ramped up for its latest operational run.
"The attainment of one megawatt in beam power symbolizes the advancement in analytical resources that are now available to the neutron scattering community through the SNS," said ORNL Director Thom Mason, who led the SNS project during its construction. "This is a great achievement not only for DOE and Oak Ridge National Laboratory, but for the entire community of science."
Before the SNS, the world's spallation neutron sources operated in the hundred-kilowatt range. The SNS actually became a world-record holder in August 2007 when it reached 160 kilowatts, earning it an entry in the Guinness Book of World Records as the world's most powerful pulsed spallation neutron source.
Beam power isn't merely a numbers game. A more powerful beam means more neutrons are spalled from SNS's mercury target. For the researcher, the difference in beam intensity is comparable to the ability to see with a car's headlights versus a flashlight. More neutrons also enhance scientific opportunities, including flexibility for smaller samples and for real-time studies at shorter time scales. For example, experiments will be possible that use just one pulse of neutrons to illuminate the dynamics of scientific processes.
Eventually, the SNS will reach its design power of 1.4 megawatts. The gradual increase of beam power has been an ongoing process since the SNS was completed and activated in late April 2006.
In the meantime, scientists have been performing cutting-edge experiments and materials analysis as its eventual suite of 25 instruments comes on line. As DOE Office of Science user facilities, the SNS and its companion facility, the High Flux Isotope Reactor, host researchers from around the world for neutron scattering experiments.
ORNL is managed by UT-Battelle for the Department of Energy.
Adapted from materials provided by
DOE/Oak Ridge National Laboratory.

Physicists Create First Atomic-scale Map Of Quantum Dots.

ScienceDaily (Sep. 30, 2009) — University of Michigan physicists have created the first atomic-scale maps of quantum dots, a major step toward the goal of producing "designer dots" that can be tailored for specific applications.
Quantum dots—often called artificial atoms or nanoparticles—are tiny semiconductor crystals with wide-ranging potential applications in computing, photovoltaic cells, light-emitting devices and other technologies. Each dot is a well-ordered cluster of atoms, 10 to 50 atoms in diameter.
Engineers are gaining the ability to manipulate the atoms in quantum dots to control their properties and behavior, through a process called directed assembly. But progress has been slowed, until now, by the lack of atomic-scale information about the structure and chemical makeup of quantum dots.
The new atomic-scale maps will help fill that knowledge gap, clearing the path to more rapid progress in the field of quantum-dot directed assembly, said Roy Clarke, U-M professor of physics and corresponding author of a paper on the topic published online Sept. 27 in the journal Nature Nanotechnology.
Lead author of the paper is Divine Kumah of the U-M's Applied Physics Program, who conducted the research for his doctoral dissertation.
"I liken it to exploration in the olden days," Clarke said of dot mapping. "You find a new continent and initially all you see is the vague outline of something through the mist. Then you land on it and go into the interior and really map it out, square inch by square inch.
"Researchers have been able to chart the outline of these quantum dots for quite a while. But this is the first time that anybody has been able to map them at the atomic level, to go in and see where the atoms are positioned, as well as their chemical composition. It's a very significant breakthrough."
To create the maps, Clarke's team illuminated the dots with a brilliant X-ray photon beam at Argonne National Laboratory's Advanced Photon Source. The beam acts like an X-ray microscope to reveal details about the quantum dot's structure. Because X-rays have very short wavelengths, they can be used to create super-high-resolution maps.
"We're measuring the position and the chemical makeup of individual pieces of a quantum dot at a resolution of one-hundredth of a nanometer," Clarke said. "So it's incredibly high resolution."
A nanometer is one-billionth of a meter.
The availability of atomic-scale maps will quicken progress in the field of directed assembly. That, in turn, will lead to new technologies based on quantum dots. The dots have already been used to make highly efficient lasers and sensors, and they might help make quantum computers a reality, Clarke said.
"Atomic-scale mapping provides information that is essential if you're going to have controlled fabrication of quantum dots," Clarke said. "To make dots with a specific set of characteristics or a certain behavior, you have to know where everything is, so that you can place the atoms optimally. Knowing what you've got is the most important thing of all."
In addition to Clarke, co-authors of the Nature Nanotechnology paper are Sergey Shusterman, Yossi Paltiel and Yizhak Yacoby.
The research was sponsored by a grant from the National Science Foundation. The U.S. Department of Energy supported work at Argonne National Laboratory's Advanced Photon Source.
Adapted from materials provided by
University of Michigan.