- A new British science program aims to produce cameras
for use in space that are so sensitive they will see through fog, smoke
and even walls and clothing.
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- The technology will detect an obscure yet ubiquitous
form of radiation known as terahertz waves, also called T-rays. Similar
cameras are also expected to have applications in airport security and
medicine.
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- One camera, already built by a company called QinetiQ
and working in so-called millimetric waves, has demonstrated the ability
to eerily peer through clothes and reveal a concealed weapon -- as well
as much of a person's body. The image shows far more detail than an infrared
camera, which detects heat.
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- Terahertz radiation is similar to but more revealing
than what the QinetiQ camera detects. Scientists say T-rays are emitted
by pretty much everything. They come from "the human hand, an envelope,
someone with clothes on or a comet," says Geoff McBride, who works
on Star Tiger, the British project. It is supported by the European Space
Agency.
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- In a telephone interview, McBride told SPACE.com that
a space-based T-ray imager could be deployed in two years if funding is
made available. The first objective might be to study Earth's atmosphere,
he said.
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- Similar but less sensitive systems are currently used
on satellites to measure sea surface temperatures.
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- "Unlike light, terahertz waves are able to propagate
through cloud and smoke, providing a powerful advantage for certain remote-sensing
measurements," according to Star Tiger officials. "From a practical
aspect they are also able to pass through windows, paper, clothing and
in certain instances even walls."
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- Eventually, a T-ray imager could be deployed to investigate
a comet's tail, McBride said.
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- Unheralded frequency
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- Low frequency versions of terahertz waves are known as
millimeter waves, and they behave much like radio waves, Star Tiger engineers
say. At higher frequencies, the terahertz waves straddle the border between
radio and optical emissions.
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- The technology, for which there is surprisingly little
literature, is sometimes referred to as quasi-optics.
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- T-ray cameras might one day be used to peer under the
skin and detect cancer, scientists say. They could also have security and
communications applications.
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- A February article on the Web site of the journal Nature
said terahertz cameras could be "the next big wave" in imaging
technology for everything from cells to stars.
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- Scientists at the Rensselaer Polytechnic Institute in
New York claim T-rays will be harnessed to speed computer memory and sharpen
flat-panel displays, as well as provide a new imaging technology that could
prove valuable for airport security.
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- "It is quite possible that plastic explosives look
very different under terahertz light and could be distinguished from the
molecular structure of suitcases, clothing, and common household materials
or equipment," says Rensselaer engineer Xi-Cheng Zhang.
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- The Star Tiger project, meanwhile, would bring leading
researchers together in a laboratory where all the equipment and support
exist to develop the necessary technology, according to a statement from
the Rutherford Appleton Laboratory in the United Kingdom.
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- One goal of the program is to prove that complicated
problems can be solved in this way. "This is complemented by the removal
of normal everyday distractions to allow the team to concentrate fully
on the technical problems," according to the statement.
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- The project will be discussed by British Science Minister
Lord Sainsbury at a ceremony on June 24.
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- http://www.space.com/businesstechnology/technology/t-ray_camera_020613.html
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