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LHC: Damage Report

Earlier this year the Large Hadron Collider was fired up, but sadly it did not take long before it broke down. In fact, only nine days after the opening CERN was forced to shut it down again due to an accident during one of the test runs. An electrical connection melted, which subsequently led to failures in the pipes containing liquid helium. Because the superconducting magnets require temperatures at about -271°C (that is only about 2 kelvins!) to function properly, they failed dramatically when the helium cooling system was damaged. When the magnets started overheating, they damaged nearby equipment with a massive burst of pressure. The forces at play were so great that several of the magnets supports were literally ripped from the ground were they were secured. 

But, they say they will be able to fix the problem, an have the LHC up and running again next summer.


December 11, 2008 Posted by | Physics | , , , , , , , , , , , | Leave a comment

New Method for Creating Antimatter Developed

Antimatter consists of antiparticles in the same way matter consists of particles, and the antimatter equivalent of, for example, a proton found in normal matter would be an antiproton. When matter meets antimatter the result is total annihilation and radiation in the form of gamma rays. As a result, producing antimatter is not easy, but scientists have recently developed a new method that produces far more of it than previous methods. 

The research was done by a team led by physicist Hui Chen at Lawrence Livermore National Laboratory in Livermore, California. They managed to create an estimated 100 billion positrons, which is the antimatter equivalent of electrons, by modifying and perfecting earlier methods. Previously, the team created positrons by shooting a short, ultra-intense laser at a paper-thin sheet of gold, but recent computer simulations suggested that they would be able to produce far more positrons by using a thicker sheet. So, when the paper-thin foil was substituted for a millimetre-thick one, they were able to create an estimated 100 billion positrons. 1 million of these were physically measured by their detectors, and the final number was inferred from that. In comparison, when the laboratory first created positrons about 10 years ago, they were able to detect only 100 particles. 

The laser used in the experiment ionizes and accelerates electrons that are subsequently driven through the gold sample. Here, they interact with the gold nuclei to give off packets of energy that then decay into matter and antimatter. 

When the universe was created in the Big Bang, the theory goes that equal amounts of matter and antimatter were created. However, after some time, due to a not fully understood process called bayrogenesis, there was a small shift in the matter-antimatter equilibrium, resulting in the dominance of quarks and leptones over antiquarks and antileptones. Even though the dominance was only about 1 particle per 30 million, it led to the development of the matter-based universe we know today. This new method of creating positrons will thus perhaps enable physicist to conduct more research into antimatter, and maybe improve our understanding of the early development of the universe. 

A bubble chamber-photograph showing the movement of elementary particles, including positrons. For more information, go here. Credit: CERN

November 18, 2008 Posted by | Physics | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 1 Comment