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■ BY JEFF ECKERT
ADVANCED TECHNOLOGIES
FUSION IGNITION A
STEP CLOSER
PHOTO COUR TES Y OF LAWRENCE
LIVERMORE NATIONAL LABORATORY.
device provides 50 percent higher performance while using only one tenth
as much power as existing designs.
Although this is not the first transistor to use InSb channels, this one,
with a gate length of 85 nm, is the
smallest ever and can operate on only
about 0.5 V. No one is speculating
about when the devices will be available for production, but the impetus
is there, as the result would be much
better performance, less heat, and
longer battery life in mobile devices.
■ The National Ignition Facility, with its
192 laser beamlines focused on a tiny
target, will be the world’s largest laser
project when completed, currently
scheduled for 2009.
scheduled for mid-2009), NIF will be
used to study and, presumably,
achieve ignition, which so far
has never been achieved
under controlled conditions in
a laboratory setting.
In the recent experiment,
four beams were fired into
various sized hohlraums for
two nanoseconds, creating
pulses of about eight trillion
watts. Although no attempt
was made to create ignition,
the researchers claim that, by
extrapolation, it is clear that
the goal is achievable when the full
complement of lasers is in place and
able to apply 1.8 million joules of
laser energy and 500 terawatts of
power.
Researchers at Lawrence
Livermore National Laboratory
( www.llnl.gov) reported conducting
some successful laser experiments at
the National Ignition Facility (NIF),
validating key computer simulations
and theoretical projections relevant
to the plasma and X-ray environment
necessary to achieve ignition (“
ignition” being the term used for starting
up a controlled nuclear fusion event).
In the process, a tiny gold-plated
cylinder called a “hohlraum” holds a
deuterium-tritium fuel capsule in the
target chamber, where the energy
from 192 high-powered lasers is converted to thermal x-rays. The x-rays
heat and ablate the plastic surface of
the ignition capsule, causing a rocket-like pressure on the capsule and
forcing it to implode and ignite, after
which is produces a burst of energy
that is greater than used to create it.
The NIF is a 10-story building in
which 192 laser beams can be focused
on a tiny target inside a 30-foot diameter aluminum-lined chamber. Eight
beams have been commissioned so
far. When fully operational (currently
INSB TRANSISTORS
DEMONSTRATED
For a couple decades now, designers and journalists alike have been
fretting about how long Moore’s Law
can be extended. (As you probably
recall, Gordon Moore, cofounder
of Intel, predicted in 1965 that the
number of transistors per square inch
on an IC would double every year. The
reality has been about every 18
months, but that is not much less
amazing.)
In any event, Intel ( www.intel.
com) has now announced development of a prototype of a new, ultra-fast, very low-power transistor that
could keep Moore an honest man for a
few more decades. Researchers from
Intel and QinetiQ ( www.qinetiq.com)
have jointly demonstrated an
enhancement-mode
transistor that uses
indium antimonide
(InSb) to conduct electrical
current. Apparently, the
PHOTO COURTESY OF MI
COMPUTERS AND
NETWORKING
HAND-CRANKED
LAPTOPS UNDER
DEVELOPMENT
It’s an ugly shade of green, is powered by cranking it up, and will sell
for only $100. It looks like a toy
because, well, for the most part it is
— at least, it is specifically designed
for children. And yet, if Nicholas
Negroponte, founding chairman of
MIT’s Media Laboratory (www.media.
mit.edu), has his way, up to 100 million children in developing countries
will be getting them for free through
the One Laptop Per Child (OLPC)
Foundation, a nonprofit group organized by Media Lab faculty but totally
■ This $100
laptop is designed
8
February 2006
T’S MEDIA LABORATORY.
for children in
developing countries.
