An Etymological Dictionary of Astronomy and Astrophysics
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A technique that uses a suitable arrangement of → laser beams and magnetic fields to capture → cesium (¹³³Cs) atoms from a thermal vapor and slow the motion of the atoms, cooling them to just a few micro-kelvins above the → absolute zero. The technique allows trapping some 10⁷ cesium atoms in a cloud a few millimeters in diameter in a few tenths of a second. At a temperature of 2 μK, the average thermal velocity of the cesium atoms is of the order of 1 cm s^-1, so they stay together for a relatively long time. The laser cooling technique is the key tool which enabled the operation of an → atomic fountain clock.

→ laser; → cooling; → technique.