Friday 19 September 2008

Atom-smasher hit by electrical hitch

The worlds largest superconducting solenoid magnet part of the experiment in smashing atoms September 10. The worlds largest particle collider has been stopped a week after its startup as a result of an electrical fault the European Organisation for  ...
The world's largest superconducting solenoid magnet, part of the experiment in smashing atoms, September 10. The world's largest particle collider has been stopped, a week after its startup, as a result of an electrical fault, the European Organisation for Nuclear Research (CERN) said.

The world's largest particle collider was stopped on Wednesday, a week after its startup, as a result of an electrical fault, the European Organisation for Nuclear Research (CERN) said on Thursday.

The problem affected a cooling system for high-powered magnets designed to steer beams of particles around the Large Hadron Collider's 27-kilometre (16.9-mile) circular tunnel, CERN said.

The LHC "is still in commissioning phase, it's a very complex tool and it's normal for there to be stoppages," a CERN spokeswoman told AFP.

Commissioning work stopped on Wednesday, but was likely to resume later Thursday, she said.

The LHC took nearly 20 years to complete and at six billion Swiss francs (3.76 billion euros, 5.46 billion dollars) is one of the costliest and most complex scientific experiments ever attempted.

It aims to resolve some of the greatest questions surrounding fundamental matter, such as how particles acquire mass and how they were forged in the "Big Bang" that created the Universe some 13.7 billion years ago.

Counter-rotating beams, comprising strings of protons, are whizzed around the tunnel and then are smashed together in four huge laboratories.

Arrays of detectors swathing the walls of these chambers will trace the sub-atomic rubble spewed out from the collision, looking for signatures of novel particles.

The September 10 switch-on saw the testing of a clockwise beam, and then an anticlockwise beam. The first collisions are not expected for a number of weeks, given the long process of testing the LHC's equipment.

The steering magnets in the LHC tunnel are chilled to as low as -271 degrees Celsius (-456.25 degrees Fahrenheit), which is close to absolute zero and colder than deep outer space.

At this extreme temperature, electrical currents overcome resistance, thus making it easier and cheaper to power electro-magnets.

Transformer Glitch Halts LHC Operations

Debris from particles hitting the collimator blocks were detected in the calorimeters and muon chambers (CERN/LHC/CMS)

Debris from particles hitting the collimator blocks were detected in the calorimeters and muon chambers (CERN/LHC/CMS)

According to reports, only a day after the first successful circulation of protons in the Large Hadron Collider (LHC) last week, operations at the world's largest particle accelerator had to be stopped due to a fault with a 30 tonne transformer used to cool part of the facility. The protons were not being accelerated at the time and there was no risk to safety at the LHC.

Rather than maintaining the equipment below the operational 2 Kelvin, the transformer glitch caused temperatures to rise to over 4 Kelvin (which is still cold, after all it is only 4 degrees above absolute zero - but it's not cold enough). The transformer failed after the successful anticlockwise circulation of protons on the evening of September 11th and rumours about LHC problems have only just been confirmed…

This was bound to be a frustrating problem for the LHC engineers, but in many respects it was inevitable. This is a facility more complex than any technology ever built; a 27 km ring of 1000 supercooled electromagnets, operating at a temperature colder than anything in the Universe, with 2000 separate power supplies and a vast number of synchronized detectors and sensors… it's little wonder the LHC may experience one or two technical hitches.

"This is arguably the largest machine built by humankind, is incredibly complex, and involves components of varying ages and origins, so I'm not at all surprised to hear of some glitches. It's a real challenge requiring incredible talent, brain power and coordination to get it running." - Steve Giddings, physics professor at University of California, Santa Barbara

However, this fault was critical to LHC operations, ultimately shutting the experiment down until technicians find the problem. Judith Jackson, spokesman for the Fermi National Accelerator Laboratory, is not surprised the LHC should suffer the occasional setback. "We know how complex and extraordinary it is to start up one of these machines. No one's built one of these before and in the process of starting it up there will inevitably be glitches," she said.

Apparently, transformer malfunctions are commonplace in particle accelerators. "These things happen," she said. "It's a little setback and it sounds like they've dealt with it and are moving forward."

According to CERN scientists, the proton beams made "several hundred orbits" clockwise and anticlockwise before the experiment had to shut down.

The Associated Press investigation into the September 11th transformer glitch indicates that the problem has been identified and CERN scientists are still on track for the first particle collisions in October.

Source: AP

Monday 15 September 2008

Hackers 'find black hole in atom smasher computers'

European Organisation for Nuclear Research (CERN) scientists work on computers at CERNs control centre in Geneva on September 10 during the switch-on of the Large Hadron Collider the worlds biggest atom-smasher. Hackers claim they have broken into th ...
European Organisation for Nuclear Research (CERN) scientists work on computers at CERN's control centre in Geneva on September 10 during the switch-on of the Large Hadron Collider, the world's biggest atom-smasher. Hackers claim they have broken into the computer system of the Large Hadron Collider, the mega-machine designed to expose secrets of the cosmos, British newspapers have reported.


Hackers claim they have broken into the computer system of the Large Hadron Collider, the mega-machine designed to expose secrets of the cosmos, British newspapers reported on Saturday.

A group calling itself the Greek Security Team left a rogue webpage mocking the technicians responsible for computer security at the giant atom smasher as "schoolkids", the Times and Daily Telegraph reported.

The hackers vowed they had no intention of disrupting the experiment at the European Organisation for Nuclear Research (CERN) on the Swiss-French border, they just wanted to highlight the flaws in the computer system's security.

"We're pulling your pants down because we don't want to see you running around naked looking to hide yourselves when the panic comes," they wrote, according to the Daily Telegraph.

The hackers claimed to have gained access to a website open to other scientists on Wednesday as the LHC passed its first test with flying colours, the reports said.

They appear to have tried to gain access to the computer system of the Compact Muon Solenoid Experiment, one of the four detectors that will be analysing the progress of the experiment.

James Gillies, a spokesman for CERN, told the Times: "We don't know who they were but there seems to be no harm done. It appears to be people who want to make a point that CERN was hackable."

Scientists hailed the success of the start of the experiment on Wednesday in the Large Hadron Collider, the 27-kilometre (16.9-mile) circular tunnel in which parallel beams of protons will be accelerated to nearly the speed of light.

Superconducting magnets will then steer the counter-rotating beams so that strings of protons smash together in four huge laboratories, fleetingly replicating the conditions that prevailed at the "Big Bang" that created the Universe 13.7 billion years ago.

Sunday 14 September 2008

Hawking bets CERN mega-machine won't find 'God's Particle' (Update)


South Africa former President Nelson Mandela (right) meets with British scientist Professor Stephen Hawking in Johannesburg. Hawking has bet 100 dollars (70 euros) that a mega-experiment this week will not find an elusive particle seen as a holy grai ...
South Africa former President Nelson Mandela (right) meets with British scientist Professor Stephen Hawking in Johannesburg. Hawking has bet 100 dollars (70 euros) that a mega-experiment this week will not find an elusive particle seen as a holy grail of cosmic science, he said.

Renowned British astrophysicist Stephen Hawking has bet 100 dollars (70 euros) that a mega-experiment this week will not find an elusive particle seen as a holy grail of cosmic science, he said Tuesday.

In the most complex scientific experiment ever undertaken, the Large Hadron Collider (LHC) will be switched on Wednesday, accelerating sub-atomic particles to nearly the speed of light before smashing them together.

"The LHC will increase the energy at which we can study particle interactions by a factor of four. According to present thinking, this should be enough to discover the Higgs particle," Hawking told BBC radio.

"I think it will be much more exciting if we don't find the Higgs. That will show something is wrong, and we need to think again. I have a bet of 100 dollars that we won't find the Higgs," added Hawking, whose books including "A Brief History of Time" have sought to popularise study of stellar physics.

On Wednesday the first protons will be injected into a 27-kilometre (16.9-mile) ring-shaped tunnel, straddling the Swiss-French border at the headquarters of the European Organisation for Nuclear Research (CERN).

Physicists have long puzzled over how particles acquire mass. In 1964, a British physicist, Peter Higgs, came up with this idea: there must exist a background field that would act rather like treacle.

Some scientists were however more optimistic.

Hubert Reeves, the French astrophysician, told the Swiss daily Le Matin that the invention could bring "unexpected results" that would change the world of particle physics forever.

"This machine will probably bring unexpected results that could turn particle physics on its head," Reeves said.

"It's a really impressive tool. It can go as deep underground as the length of a cathedral," he said.

Particles passing through it would acquire mass by being dragged through a mediator, which theoreticians dubbed the Higgs Boson.

The standard quip about the Higgs is that it is the "God Particle" -- it is everywhere but remains frustratingly elusive.

While questioning the likelihood of finding Higgs Bosons, Hawking said the experiment could discover superpartners, particles that would be "supersymmetric partners" to particles already known about.

"Their existence would be a key confirmation of string theory, and they could make up the mysterious dark matter that holds galaxies together," he told the BBC.

"Whatever the LHC finds, or fails to find, the results will tell us a lot about the structure of the universe," he added.

Hawking, the 66-year-old Lucasian Professor of Mathematics at Cambridge University, was diagnosed with the muscle-wasting motor neuron disease at the age of 22.

He is in a wheelchair and speaks with the aid of a computer and voice synthesiser.

Physicists hope to tie light beams in knots


Usually, light beams shine in a straight line, with the possible exception of light being bent by gravity. But scientists are now investigating how to make light beams into looped and knotted configurations. The possibility for these structured light beams arises from some curious solutions to Maxwell’s equations, which describe the fundamentals of electricity and magnetism.

Physicists William Irvine of New York University and Dirk Bouwmeester of the University of California, Santa Barbara, and Leiden University in The Netherlands have published a study in Nature Physics on their analysis of knotted light. The scientists looked at the physical properties of knotted light and discovered that it can be experimentally generated using circularly polarized laser beams.

In some little-known solutions to Maxwell’s equations, all the electric and magnetic field lines form circles that are all linked to each other. These loops of field lines can be used to construct the donut shape of a torus. In such a scenario, each circle wraps around the torus once, and no two circles cross each other. Smaller tori could then be nested within larger ones, filling three-dimensional space with circles of light beams.

These solutions differ from any known existing form of light because of the intricate knotted structure, the physicists told PhysOrg.com. As they explained, this structure is based on the Hopf fibration, which was introduced in 1931 to mathematically investigate the structure of spheres in four and higher dimensions, a topic that seemingly has nothing to do with light.

After investigating knotted light’s properties, the physicists determined that they could use laser fields to create the structures. Starting with a single-pulsed beam of circularly polarized light, and tightly focusing the beam, it should be possible to create various shapes of looped light beams. By using holographic techniques and a spatial light modulator, the shape and profile of the looped light could also be controlled. These same techniques have recently been used to produce Airy beams, which are light beams that don’t spread out as they propagate.

Currently the physicists are preparing for an experimental realization of the new solutions either using electromagnetic radiation in the optical regime, i.e. light, or in the microwave regime. The main challenge will be to deal with ultra-short pulses of radiation in order to create a broad spectrum of frequencies as needed for the construction of the light knots.

Because knotted light beams have both beamlike properties and unique unexplored properties, the physicists predict that creating the beams could have applications in several areas. These could include applications in plasma confinement, atomic particle trapping, manipulating cold atomic ensembles, and generating soliton-like solutions in nonlinear media.

More information: Irvine, William T. M. and Bouwmeester, Dirk. “Linked and knotted beams of light.” Nature Physics, Vol. 4, September 2008, pp. 716-720.

Monday 8 September 2008

Mysterious Forces

For the last 10 years physicists have been puzzled by a mysterious force acting on space probes. There have been various slight anomalies detected in how spacecraft move which don't seem to be moving quite as we would predict them to.

One of the first anomalies was noticed on the pioneer spacecraft that visited the outer solar system in the 1970s and are still heading off into space. They seem to be slowing down slightly faster than we would predict using our present understanding of physics. This effect is minute, about a ten billionth as strong as the force of gravity on the surface of the earth but it is measurable. This effect could just be due to some physics we already understand, like a gas leak or we don't understand how the probe is radiating heat.

GalileoNow a team from the jet propulsion laboratory in California have found another anomaly which seems to appear when some spacecraft make a flyby of earth. For examble when the NEAR spacecraft flew past the earth on its way to visit an asteroid, it left moving at 13mm/s slower than it should have done, and the Galileo probe was speeded up by 4mm/s these are tiny effects as the probes are moving more than a million times faster than this, but it is well within our ability to measure their speeds.

Some probes have this effect and others don't, Frank Jordan who is part of the team which was looking at this effect and trying formulae to try and model these results and found one that works nicely. It seems to suggest that probes which approach and leave the earth at a similar angle to the equator won't feel an effect, but probes which enter and leave at different angles feel this strange extra force.

This doesn't say anything about what could be causing the force, but the fact that the equator is important could indicate that the earth's rotation is affecting it somehow. Einstein's theory of general relativity suggests some effects related to rotating massive objects, but they should be much smaller than this, so it is just possible that these may be some hints at some interesting new physics.

Sunday 7 September 2008

Solar energy can meet all the world's energy demands - experts

A solar thermal electric power plant in Sanlucar La Mayor in February 2008. The world must speed up the deployment of solar power as it has the potential to meet all the worlds energy needs the chairman of an industry gathering which wrapped up Frida ...
A solar thermal electric power plant in Sanlucar La Mayor in February 2008.

The world must speed up the deployment of solar power as it has the potential to meet all the world's energy needs, the chairman of an industry gathering which wrapped up Friday in Spain said.

"There is thus an enormous resource available from photovoltaics, which can be used everywhere, and can in principle cover all the world energy demand from a renewable, safe and clean source," he added.

Lincot, the research director of the Paris-based Institute for Research and Development of Photovoltaic Energy, said solar energy was growing rapidly but still made only a "negligible" contribution to total energy supply.

Last year the world production of photovoltaic models represented a surface of 40 square kilometres (16 square miles) while meeting the electrical consumption of countries like France or Germany would require 5,000 square kilometres, he said.

Under current scenarios, photovoltaic models will represent about 1,000 square kilometres by 2020 accounting for about only 3.0 percent of energy needs in the 27-member European Union, he added.

Over 200 scientists and solar power experts have signed a declaration calling on the accelerated deployment of photovoltaic power which was launched at the conference.

More than 3,500 experts and 715 sector firms took part in the gathering, billed as the largest conference ever organised in the field of photovoltaic conversion of solar energy.

Germany and Spain are the world leaders in solar energy power. Germany has 4,000 megawatts of installed capacity while Spain has 600 megawatts.