ความคิดเห็นที่ 4
 
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Does antimatter exist?
Yes, it does, and we produce it routinely at CERN. Antimatter was predicted by P.A.M. Dirac in 1928 and the first antiparticles were discovered soon after by Carl Anderson. CERN is not the only research institute to produce and study antimatter.
Do antimatter atoms exist?
The team of the PS210 experiment at the Low Energy Antiproton Ring (LEAR) at CERN made the first anti-hydrogen atoms in 1995. Then, in 2002 two experiments (ATHENA and ATRAP) managed to produce tens of thousands of antihydrogen atoms, later even millions. However, although "tens of thousands" may sound a lot, it's really a very, very small amount. You would need 10,000,000,000,000,000 times that amount to have enough anti-hydrogen gas to fill a toy balloon! If we could somehow store our daily production, it would take us several billion years to fill the balloon. But the universe has been around for only 13.7 billion years...So the Angels and Demons scenario is pure fiction.
Do you make antimatter as described in the book?
No. The production and storage of antimatter at CERN is not at all as described in the book: you cannot stand next to the Large Hadron Collider (LHC) and see it come out, especially since the LHC accelerator is not yet in operation.
To make antiprotons, we collide protons at nearly the speed of light (to be precise, with a kinetic energy of about 25 GeV) with a block of metal, e.g. copper or tungsten. These collisions produce a large number of particles, some of which are antiprotons. Only the antiprotons are useful, and only those that fly out in the right direction. So that's where your energy loss goes: it is like trying to water a pot of flowers but with a sprinkler that sprays over the whole garden. Of course, we constantly apply new tricks to become more efficient at collecting antiparticles, but at the level of elementary particles this is extremely difficult.
จากคุณ :
ginosty  
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16 พ.ค. 52 19:35:48
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