Crystalline construction

Researchers at the University of
Leiden, the Netherlands, have photographed images of the growth of
Helium-3 crystals. The crystals,
grown at a temperature of 0.001'
Kelvin - close to the lowest temperature obtainable theoretically,
which is 0* Kelvin - were shot by a
charge-coupled device camera
(Science, Vol 268, No 5216).

Because the camera only operates above 60' Kelvin, it was shield-
ed inside a copper box and placed
inside the cryostat, the setup which
produces the low temperature. Light
pulses from a light-emitting diode
were directed towards the crystal
with the help of a minute glass fibre.
The video images, apart from being
a technological wonder, will provide
researchers valuable insights into
the properties of crystals.