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Tonight's C.S.I. episode: Angel decimated. Pin head suspected. Harry ----- Original Message ----- From: Terry Blanton <[EMAIL PROTECTED]> Date: Friday, November 21, 2008 4:00 pm Subject: Re: [Vo]:making antimatter > Kewl, now we can realize "Angels and Demons" (coming to a theatre > near you). > > Terry > > On Fri, Nov 21, 2008 at 3:53 PM, Harry Veeder <[EMAIL PROTECTED]> wrote: > > > > > > > >> News > >> Laser creates billions of antimatter particles > >> Wednesday, 19 November 2008 > >> Cosmos Online > >> > >> > >> Positron factory: Physicist Hui Chen sets up targets for the > anti- > >> matter experiment at the LLNL laser facility. > >> > >> Credit: LLNL > >> > >> SYDNEY: By shooting a laser through a gold disc no bigger than the > >> head of a drawing pin, physicists have created more than 100 > >> billion particles of antimatter. > >> The ability to create vast numbers of positrons in the laboratory > >> opens the door to new avenues of research, they say. These include > >> an understanding of the physics behind black holes, gamma ray > >> bursts and why more matter than antimatter survived the Big Bang. > >> > >> Super-sized portion of positrons > >> > >> "We've detected far more antimatter than anyone else has ever > >> measured in a laser experiment," said Hui Chen, a physicist at the > >> Lawrence Livermore National Laboratory (LLNL) in California, U.S., > >> who led the experiment. "We've demonstrated the creation of a > >> significant number of positrons using a short-pulse laser." > >> > >> Previous experiments made smaller quantities of positrons using > >> lasers and paper-thin targets - but new simulations showed that > >> millimetre-thick gold could be a far more effective source, said > >> the researchers, who report their finding this week at the American > >> Physical Society's Division of Plasma Physics Meeting in Dallas, > >> South Carolina. > >> > >> Chen and her team used a short, ultra-intense laser to irradiate a > >> millimetre-thick gold target. > >> > >> In the experimental set-up, the laser ionises and accelerates > >> electrons, which are driven right through the gold target. On their > >> way, the electrons interact with the gold nuclei, which serve as a > >> catalyst to create positrons. > >> > >> Electron's opposite number > >> > >> The electrons give off packets of pure energy, which decay into > >> matter and antimatter, following the predictions of Einstein's > >> famous equation that relates matter and energy. By concentrating > >> the energy in space and time, the laser produces positrons more > >> rapidly and in greater density than ever before in the laboratory. > >> > >> Positrons are the antimatter equivalent to the electron, and behave > >> in a similar way, though they have the opposite charge (see, New > >> twist to matter-antimatter mystery, Cosmos Online). > >> > >> The researchers took advantage of this property to detect them, by > >> using a typical device to detect electrons (a spectrometer) and > >> equipping it to detect particles with opposite polarity as well. > >> > >> "By creating this much antimatter, we can study in more detail > >> whether antimatter really is just like matter, and perhaps gain > >> more clues as to why the universe we see has more matter than > >> antimatter," said LLNL team member Peter Beiersdorfer. > >> > >> > >> "We've entered a new era," Beiersdorfer added. "Now, that we've > >> looked for it, it's almost like it hit us right on the head. We > >> envision a centre for antimatter research, using lasers as cheaper > >> antimatter factories." > >> > >> Particles of antimatter are almost immediately annihilated by > >> contact with normal matter, and converted to pure energy in the > >> form of gamma rays. > >> > >> There is considerable speculation as to why the observable universe > >> appears to be almost entirely matter, whether other universes could > >> be almost entirely antimatter, and what might be possible if > >> antimatter could be harnessed. > >> > >> Product of energetic celestial events > >> > >> Normal matter and antimatter are thought to have been in balance in > >> the very early universe, but, due to a mysterious 'asymmetry', the > >> antimatter decayed or was annihilated, and today very little > remains.>> > >> Over the years, physicists had theorised about antimatter, but it > >> wasn't confirmed to exist experimentally until 1932. > >> > >> High-energy cosmic rays impacting Earth's atmosphere produce minute > >> quantities of antimatter in the resulting jets, and physicists have > >> learned to produce modest amounts of anti-matter using traditional > >> particle accelerators and smaller laser set-ups in the lab. > >> > >> Antimatter may also be churned our in regions like the centre of > >> the Milky Way and other galaxies, where very energetic celestial > >> events occur. The presence of the resulting antimatter is > >> detectable by the gamma rays produced when positrons are destroyed > >> when they come into contact with nearby matter. > >> > >> ### > >> With the Lawrence Livermore National Laboratory. > >> > >> > >> [Non-text portions of this message have been removed] > > > > > >
