New pint sized particle accelerator leads the way to clean nuclear energy

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The EMMA ring in relation to the main ERLP (ALICE) accelerator.

(PhysOrg.com) -- Researchers at Daresbury science park in Britain have offered a glimpse into what might be the future of nuclear energy production by showcasing a scaled down particle accelerator; one, that when combined with others just like it, could produce nuclear energy based on thorium, rather than uranium. Dubbed the Electron Machine with Many Applications (EMMA), the accelerator, a much smaller version of the kind used in physics research, such as the Large Hadron Collider, could be used to provide an accelerated beam necessary for the type of nuclear reaction used in a theoretical thorium plant.

Thorium, named for the Norse god of thunder, is a silver-white metal found in abundance all over the planet, and is only very slightly radioactive and as such is a member of the elements known as actinides which, like uranium, occasionally spin off particles which make it useful for energy production. But unlike uranium, thorium is relatively clean because it decays much faster leaving far less reactive byproducts behind; and because it requires a constant bombardment of particles to keep it reacting, is incapable of producing a meltdown; something on the minds of people in the aftermath the Fukushima disaster.

That?s where EMMA enters the picture. To produce the constant stream of particles needed to keep a thorium reaction going, an accelerator is needed, but it wouldn?t have to be the huge billion dollar kind, more like the kind you could fit in your garage, or in this case in a lab on the boggy Cheshire flatland, just east of Liverpool, where reporters from the U.K. newspaper Mail, were recently given a tour. They report that EMMA is ?an object of scientific beauty...?

Scientists have known since the 1950?s that thorium could be used to produce electricity, just as uranium is today; what kept them from doing so was the desire to use technology that could be used in conjunction with atomic weapons, which pushed thorium research aside due to its impracticality for such applications. Today however, things have obviously changed, several countries besides Britain are taking a very hard look at thorium and the ways it could be put to good use and at small particle accelerators too; the team in Britain is also currently at work designing the Particle Accelerator for Medical Applications (Pamela) to be used to help treat hard to reach cancer in patients.

2010 PhysOrg.com

Fermilab experiment fails to confirm new particle claim

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DZero data: If DZero were to detect the new particle that CDF detected, there should have been a signal around 145 GeV/c2 (dashed line). The red peak below 100 GeV/c2 is a feature of W and Z boson decays that is predicted by the Standard Model. Image credit: Fermilab

(PhysOrg.com) -- In April, scientists at one of Fermilab?s two particle detectors, CDF, observed what they thought might be a new particle not predicted by the Standard Model. But now, scientists at the lab?s second detector, DZero, have cross-checked the observation with their own independent data and analysis tools, and have found no evidence of a new particle. Instead, the DZero data are in agreement with predictions from the Standard Model.

Originally, CDF scientists observed the possible new particle when analyzing proton-antiproton collisions that produce a W boson - a particle associated with the weak nuclear force - and two jets of particles. At a collision energy of about 145 GeV, the scientists observed about 253 more electrons and muons than expected. The excess implies the existence of a particle with a mass of 145 GeV, but no known particles have this mass. The finding led the scientists to predict the existence of a new particle with a mass of 145 GeV that decays into an extra W boson that in turn decays into electrons and muons, in addition to other decay products. Some theorists suggested that the new particle might provide evidence for a fifth fundamental force of nature known as "technicolor.?

At first, the effect at CDF had a magnitude of three standard deviations, or ?three sigma,? which means that there is about a 1 in 1,000 chance that the result is attributable to some statistical fluctuation in the data. In particle physics, the three-sigma level of certainty is intriguing, but a five-sigma level (about a 1 in 1 million chance that the result is a fluke) is needed to claim a discovery. Then, at a conference on May 30th at Blois, France, CDF co-spokesperson Giovanni Punzi announced that the scientists had analyzed more data and the effect was now at just below the five-sigma level.

So DZero?s failure to confirm the same excess at 145 GeV is a bit of a letdown. On the other hand, it raises the question of what exactly is causing the discrepancy between the two results. Fermilab has two detectors for this very reason, to check each other?s results. However, disagreements like this one don?t occur very often. For the more than 500 measurements that CDF and DZero have independently detected and analyzed over the past 10 years, the results have agreed more than 99% of the time.

?This is exactly how science works,? said DZero co-spokesperson Stefan S?ldner-Rembold in a Fermilab press release. ?Independent verification of any new observation is the key principle of scientific research. At the Tevatron, we have two experiments that, by design, can check each other.?

Going forward, Fermilab plans to create a task force that will consist of scientists from both CDF and DZero to coordinate an analysis of the two detectors? results in order to understand the disagreement.

The investigation for the possible 145-GeV particle could be one of the last opportunities to discover new physics at Fermilab?s Tevatron, at least while it?s still running. The collidor is scheduled to be shut down this September due to budget cuts at the US Department of Energy. After the final shutdown, scientists will still have billions of collision events to sift through, and they expect that data analysis will continue for at least five more years.

More information: DZero paper (submitted to Physical Review Letters) and CDF paper (published in Physical Review Letters)

via: Fermilab press release, BBC News, Wired

2010 PhysOrg.com