by Jeff Eckert
Events, Advances, and News
From the Electronics World
New Way to Look at Things
Aprototype microscope that uses
neutrons instead of light to
“see” magnified images has been
demonstrated at the National Institute
of Standards and Technology
(NIST, www.nist.gov). The hope
is that neutron microscopes may
eventually offer advantages over
optical, X-ray, and electron imaging
techniques, including better
contrast for biological samples.
Adelphi Technology, Inc. (www.
adelphitech.com), designed and
demonstrated the microscope
with the help of NIST scientists,
who routinely use multiple lenses
to focus neutron beams for other
research. Stanford University also
participated in the research,
which was supported in part by
the US Department of Energy.
The imaging process involves
hitting a sample with an intense
Neutron micrography, such the image of
a rat’s foot shown at right (b), may offer
advantages over existing X-ray and electron
imaging techniques (a). Courtesy of
Adelphi Technology, Inc.
neutron beam. The neutrons that
pass through — thereby creating a
pattern that reflects the sample’s
internal structure — are directed to a
row of 100 dimpled aluminum plates.
Each dimpled plate acts like a weak
focusing lens for neutrons, diverting
their paths slightly at each interface.
The image is then projected onto a
In principle, neutrons could
provide better image resolution than
visible light because they have shorter
wavelengths — as short as 1 nm. In
this demonstration, the microscope
produced a resolution of only
0.5 mm and a magnification of about
10. However, Adelphi hopes
to substantially improve image
resolution through research to reduce
lens aberrations. The company also
hopes to build a compact, laboratory-scale neutron source.
Moreover, neutrons offer some
unique advantages. Unlike other
imaging methods, neutrons interact
strongly with hydrogen — an important
component of biological samples
composed mostly of hydrocarbons
and water. Also, neutrons easily
penetrate samples, thereby reducing
the artifacts produced with other
techniques that require thin slices,
staining, or fixing.
Miniature Hotplates Reach
1, 100° C
NUTS & VOLTS
Silicon carbide micro-hotplates, each
consisting of a central plate surrounded by
curved tethers. The largest is less than
100 µm across.
Circle #64 on the Reader Service Card.