Pass a neutron through a refrigerator and you get a cold neutron. No,
this is not a prank, it is a boon to physics, say scientists working at
the National Institute of Standards and Technology in Gaithersburg, Maryland.
Last week, NIST inaugurated its long-awaited cold neutron facility.
Neutrons from a specially designed nuclear reactor are run through a
chamber refrigerated to -248 掳C. They come out as slower, less energetic
neutrons that can be used to penetrate and illuminate materials.
Cold neutrons can highlight tiny cracks or voids that X-rays or electron
beams cannot reach. They can 鈥榮ee鈥� light elements better than X-rays, and
distinguish between elements such as hydrogen and its chemical twin, deuterium.
They are especially useful for studying new polymers and superconductors,
the magnetic properties of alloys and the new generation of engineered biomolecules.
They may also have applications in the manufacture of semiconductors.
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