Wednesday, February 14, 2007

Plasma wakefield accelerator doubles particle energy in just one meter

Physicists in the US claim to have doubled the 42 GeV electron-beam energy of the three-kilometre-long Stanford Linear Accelerator Centre (SLAC) by simply adding a metre-long device on the end. The device, which uses a plasma wakefield to accelerate a small fraction of the electron beam, could allow conventional particle accelerators to reach higher energies (Nature 445 741).

Plasma acceleration is a technique for accelerating charged particles, such as electrons, positrons and ions, using an electric field associated with an electron plasma wave. The wave is created by the passage of a very brief laser or electron pulse through the plasma. The technique appears to offer a way to build high performance particle accelerators of much smaller size than conventional devices at the expense of coherency. Current experimental devices show accelerating gradients several orders of magnitude better than current particle accelerators. For example, one experimental device at the Lawrence Berkeley National Laboratory accelerates electrons to 1 GeV over about 3.3 cm, whereas the SLAC conventional accelerator requires 64 m to reach the same energy. (Via Wikipedia)

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