Smaller and faster

Smaller and faster A FRESH approach has paved the way for small and compact high energy accelerators to propel electrically charged atomic and subatomic particles such as electrons and protons. Chandrashekar Joshi, A Lal and their colleagues from the department of electrical engineering at the University of California at Los Angeles claim that using the new technique in their laboratory, they have achieved particle acceleration that is 30 times higher than that achieved in conventional accelerators (Nature, Vol 368, No 6471).

In particle accelerators, particles are propelled to high speeds in a vacuum and then made to bombard atomic nuclei to gain an insight into the complex world of atoms. These accelerators are massive -- the one at Fermilab, one of the foremost high-energy physics labs in the US, has two rings that have a circumference of 6.3 km -- and extremely expensive.

The ULCA team based their experiment on the "laser beat wave" theory proposed by scientists J M Dawson and T Tajima 10 years ago which states that laser beams can accelerate electrons to the speed of light of matter in which all molecules are in a nearly equally positively and negatively charged state. They used a carbon dioxide laser beam to generate plasma waves and make electrons present in the plasma ride on the plasma waves, much like a surfer on an ocean wave, gaining acceleration and then outrunning the waves.

Robert Bingham of UK's Rutherford Appleton Laboratory says that though the "bench-top" accelerator developed by Joshi and his colleagues cannot compete with the present particle accelerators in terms of energy generated, their ability to accelerate particles to extremely high speeds would open up exciting new fields such as filming in slow motion hitherto unseen chemical reactions or biological processes.

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