Full body scanners: millimetre waves pass through powder

[Eric J in MN]

http://www.independent.co.uk/news/uk/home-news/are-planned-airport-scanners-just-a-scam-1856175.html

Since the (Detroit bomber) attack was foiled, body-scanners, using "millimetre-wave" technology and revealing a naked image of a passenger, have been touted as a solution to the problem of detecting explosive devices that are not picked up by traditional metal detectors – such as those containing liquids, chemicals or plastic explosive.

But Ben Wallace, the Conservative MP, who was formerly involved in a project by a leading British defence research firm to develop the scanners for airport use, said trials had shown that such low-density materials went undetected.

Tests by scientists in the team at Qinetiq, which Mr Wallace advised before he became an MP in 2005, showed the millimetre-wave scanners picked up shrapnel and heavy wax and metal, but plastic, chemicals and liquids were missed.

If a material is low density, such as powder, liquid or thin plastic – as well as the passenger's clothing – the millimetre waves pass through and the object is not shown on screen. High- density material such as metal knives, guns and dense plastic such as C4 explosive reflect the millimetre waves and leave an image of the object.

[dkf]

1. And what are these "millimetre-waves"?

Are they bad for us?

[Eric J in MN]

2. health effect

http://www.technologyreview.com/blog/arxiv/24331/

The evidence that terahertz radiation damages biological systems is mixed. "Some studies reported significant genetic damage while others, although similar, showed none," say Boian Alexandrov at the Center for Nonlinear Studies at Los Alamos National Laboratory in New Mexico and a few buddies. Now these guys think they know why.

Alexandrov and co have created a model to investigate how THz fields interact with double-stranded DNA and what they've found is remarkable. They say that although the forces generated are tiny, resonant effects allow THz waves to unzip double-stranded DNA, creating bubbles in the double strand that could significantly interfere with processes such as gene expression and DNA replication. That's a jaw dropping conclusion.

And it also explains why the evidence has been so hard to garner. Ordinary resonant effects are not powerful enough to do do this kind of damage but nonlinear resonances can. These nonlinear instabilities are much less likely to form which explains why the character of THz genotoxic effects are probabilistic rather than deterministic, say the team.

This should set the cat among the pigeons. Of course, terahertz waves are a natural part of environment, just like visible and infrared light. But a new generation of cameras are set to appear that not only record terahertz waves but also bombard us with them. And if our exposure is set to increase, the question that urgently needs answering is what level of terahertz exposure is safe.

[dkf]

4. Looks like the terrorists will kill us by giving us cancer

not by taking down our planes.

[WillieW]

6. When will these scanners be used? I be flying from Frankfurt to DC tomorrow and I am worried

about the radiation

[Shallah Kali]

3. unlikely to work so of course the US is buying $25 Mill to get 150 of 'em

http://money.cnn.com/2010/01/05/technology/full_body_scanner/

Kant said the U.S. government has given the TSA the green light to spend $173 million on scanners, which includes the initial $25 million contract.

"Should we get additional orders, we will have to hire additional manufacturing positions," he said in an e-mail to CNNMoney.com.

Horowitz would not specify how much money had been earmarked for TSA spending on scanners, but she said the agency has enough funds that would come from the stimulus program and other federal sources to buy an additional 300 scanners.

The backscatter scanners will be used in airports around the country, but the TSA would not say where. One-third of the backscatter scanners have already been delivered, said Kant.

video of scanner in use http://www.liveleak.com/view?i=972_1262283908

[Eric J in MN]

7. That CNN reporter just asked the vice-president of the company about their machines effectiveness.NT

NT

[reggie the dog]

5. so i can tape cocaine to my leg but not cannabis when flying

great, except that I dont do cocaine.....

[seabeyond]

8. dont work, could cause health problems, eliminate rights... but hey, you oppose, you prude.

boy howdy and then on top of that, a cavity bomb and we have all the more reason for these detectors

are the pro scanner people feeling safer now?