1970
Improving Antenna Design and Performance
The 1,000 satellites
orbiting the Earth today would be space junk without high-performance,
cost-effective antennas to transmit and receive communications signals.
Among NISTs pivotal contributions to antenna technology was
the development of a theory that made it practical for researchers
to compute an antennas complex outdoor radiation pattern using
data collected entirely indoors near a test antenna. (Photo at right
shows an antenna being readied for near-field measurements.) NIST
also developed software for using the data to compute field performance;
the source code remains in use today. These advances have saved
millions of dollars in testing costs for the military and satellite
manufacturers, among other users.
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1971
A New Kind of Microscope
The scanning
tunneling microscope (STM), widely used today in fields ranging
from molecular biology to nanotechnology, enables scientists to
see and manipulate individual atoms on surfaces and understand some
of the physical, electronic, and magnetic structures of surfaces.
It is such an important tool that, in 1986, two IBM Corp. scientists
shared the Nobel Prize in physics for building the first STM able
to glimpse the atomic surface. Today, there are about 5,000 STMs
and related instruments in use throughout the world.
Some 15 years
before, NIST physicist Russell Young built the Topografiner (see
at right), a novel microscope that surveyed surfaces in great detail,
nearly to the level of individual atoms. With this instrument, Institute
researchers demonstrated the operating principle of the STM. The
Nobel committee credited Young with being the first to demonstrate
the use of a sharp-tipped stylus, held at a very small and constant
distance above a sample, to scan and map surfaces. The committee
also recognized Young for proposing to use tunneling
currenta quantum mechanical phenomenonas the means to
image surfaces. Today, the Topografiner resides in the Smithsonian
Institution.
Youngs
work is a highlight of extensive NIST research on surfaces, sometimes
described as a fourth state of matter because they are so different
from solids, liquids, and gases. Rapid advances in surface science
at NIST and elsewhere from the 1960s through the present have contributed
to the development of catalysts, semiconductor devices, chemical
sensors, and computing systems. In 1985, for example, Institute
researchers demonstrated magnetic imaging using scanning electron
microscopy with polarization analysis (SEMPA), a new type of microscopy
they developed to observe magnetic structures up to 100 times smaller
than can be seen using optical techniques. Since then, SEMPA has
assisted in the rapid development of high-density magnetic data-storage
systems.
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1971
The Origins of Closed Captioning
In an example
of a research technology with significant commercial spin-offs,
NIST's TvTime, a method for broadcasting time and frequency information
on television, was transformed into closed captioning. Approved
for wide use by the Federal Communications Commission in 1976, the
technology won an Emmy Award for outstanding achievement in engineering
development in 1980. It has greatly benefited the deaf and hard
of hearing. Today, closed captioning is used on virtually all nationally
broadcast programming, most new syndicated programming, many cable
programs, and thousands of motion pictures. It also created a new
industry of suppliers of closed captioning services.
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1972
Making Better Measurements
Measurements
have a symbiotic relationship with science and technology. They
depend on each other, and if one advances, the other does too.
A case in point
is the work of Ken Evenson and his team at NISTs Boulder campus,
who made a world-record measurement of the frequency of laser light
in 1972. That led to a much more accurate value for the speed of
light, thus enabling scientists to better understand the behavior
of the universe and more accurately track satellites and spaceships.
The ripple effect of the advance then came back full circle to measurement
science in the form of a new, more stable definition of the meter.
NIST actually
achieved nine world-record measurements of laser frequency between
1969 and 1979. But the one in 1972 was special because the laser
was stabilized, ensuring that any other similar laser will operate
at the same frequency so that the experiment can be repeated. This
design also enabled accurate independent measurements of the lights
wavelength.
Wavelength
multiplied by frequency equals the speed of lightwhich in
this case was 100 times more accurate than the value accepted for
the previous 15 years. The new value for the speed of light was
accepted internationally in 1973 (and finalized in the 1983 redefinition
of the meter).
Because frequency
can be measured more accurately than wavelength (in fact, frequency
is the most accurately measured value in science), scientists then
wanted to improve the standard of length, which had been defined
in terms of the wavelength of a certain type of light. In 1983,
based largely on the achievements of Evenson and his team, the meter
was formally redefined in terms of the new value for the speed of
light.
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1977
Safeguarding Electronic Data
About the time
the personal computer was invented, NIST issued the first publicly
available data encryption standard (DES)a landmark event in
an era when most cryptographic equipment was either proprietary
or classified.
DES has secured
much of the worlds electronic data ever since. It was the
first cryptographic algorithm endorsed by the federal government
and was embraced by the private sector, especially banking, where
it protects billions of dollars in transfers and other financial
transactions daily. When a person withdraws cash from an automated
teller machine, for instance, his or her personal identification
number is probably encrypted using DES.
Reflecting
the popularity of DES, four leading standards-setting organizations
participated in the development of DES-based cryptographic standards
for financial data, information processing and financial services,
federal procurement, and telecommunications security.Commercial
hardware and software products also rely on it. The most recent
industry survey showed that, as of late 1997, almost half of U.S.
cryptographic products and 43 percent of foreign products used DES.
The DES algorithm
was developed by IBM Corp. However, NIST played a major role in
the resulting popu-larity of the technology by making it a standard
for federal agencies, assuring that the standard met all requirements
and was acceptable to many potential users, analyzing security concerns,
and evaluating the costs and benefits of modifying or replacing
the standard. The thoroughness of the testing is reflected by the
fact that, even 23 years after it was issued, DES is still considered
unbreakable except by brute force (i.e., using computers to try
every possible 56-bit key). Today, NIST is coordinating the development
of a more powerful successor standard.
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1979
In Semiconductors, Smaller Is Better
As integrated
circuits (computer chips) shrink in size, the semiconductor industry
needs increasingly tiny rulers for measuring the widths
of circuit features. If feature size is not controlled, then the
chips may fail. Who better to meet this need than NIST, which has
assisted the semiconductor industry for more than 45 years?
When the feature-size
issue first arose, NIST created an entirely new measurement system
and, in 1979, issued its first photomask linewidth standard, which
became an instant best seller. Three leading companies stopped using
internal standards and adopted the one from NIST. This standard
reduced measurement discrepancies among companies tenfold, stimulated
the production of new commercial instruments, extended the range
of use of optical microscopes, and saved the industry millions of
dollars annually.
By the mid-1980s,
chip features were on the order of 1 micrometer wide (75 to 100
times thinner than a human hair). Today, dimensions are about one-tenth
that size. To meet todays needs, NIST has responded with photomask
linewidth standards with ever smaller features, as well as several
new approaches for accurately measuring circuit features as small
as one-tenth of a micrometer (or less). Methods that use the spacing
between crystalline silicon atoms or direct counting of the atoms
as the ruler are currently being pursued. NIST researchers also
are developing special microscopic techniques for use as calibration
and metrology tools.
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Date created:
11/2/00
Last updated: 11/7/00
Contact: inquries@nist.gov
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