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Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
Hi all. As it appears that the TSA/etc has decided to install backscatter X-ray units at airports/etc (and will soon be putting them on lamp posts/supermarkets/etc if you believe the UK papers, I am concerned about my radiation exposure.
So maybe there is a way to inform people of the risk- the "Screamer" Build a small device (ideally wristwatch sized) that when exposed to radiation loudly informs everyone around of this fact. "Caution- Ionising Radiation detected." in a Hawking-esque voice would probably work.
Would also have a use in the unlikely event of an accidental radiation release or another Chernobyl. Then there's that rather large nuke plant built ON a fault line in Japan... (!)
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
That's a neat idea! I'll be traveling by air in a few months, I can't quite imagine what kind of radiation detector a Mr Sulaiman Abdullah could carry around without causing confusion. Probably better I don't bother.
... not Russel! Registered Member #1
Joined: Thu Jan 26 2006, 12:18AM
Location: Tempe, Arizona
Posts: 1052
Conundrum wrote ...
Hi all. As it appears that the TSA/etc has decided to install backscatter X-ray units at airports/etc (and will soon be putting them on lamp posts/supermarkets/etc if you believe the UK papers, I am concerned about my radiation exposure.
A backscatter x-ray scan subjects a person to about 5 microrems of radiation. Consider that a person will naturally get 275 microrems per day at sea level. 25 millirems annually is considered a safe level of exposure from a single source, a limit which would not be reached unless a person received more than 13 scans per day, 365 days per year. So, it should be understood that unless these really are placed just about everywhere and used on people without consent, the radiation danger is minimal. I suppose that's where the watch comes in.
As for the watch, a 1N4007 will produce a small current in the presence of x-rays. Shouldn't be too hard to detect this current and trigger an alarm. Might be a challenge to string together enough of them to detect the relatively small amount of radiation, however. I also doubt anyone will let you borrow a backscatter machine to verify that your detector is working.
Registered Member #63
Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425
Sulaiman wrote ...
I can't quite imagine what kind of radiation detector a Mr Sulaiman Abdullah could carry around without causing confusion. Probably better I don't bother.
LOL, could be worse, Sulaiman -- I have a friend with the same name as a 9/11 bomber!
wrote ... Build a small device (ideally wristwatch sized) that when exposed to radiation loudly informs everyone around of this fact.
Don't walk into an airport with anything that resembles loose wires or veroboard; that's mostly what they tell staff to watch out for. Green double-sided PCBs, a silk-screened panel and you should be fine!
... not Russel! Registered Member #1
Joined: Thu Jan 26 2006, 12:18AM
Location: Tempe, Arizona
Posts: 1052
Blackplasma wrote ...
Don't walk into an airport with anything that resembles loose wires or veroboard, that's mostly what they tell staff to watch for. Green double-sided PCBs, a silk-screened panel and you should be fine!
A good point. If it's going to be a verbal warning, I'd also advise against it literally saying "run away." Something along the lines of "danger, ionizing radiation detected" should suffice.
Registered Member #1334
Joined: Tue Feb 19 2008, 04:37PM
Location: Nr. London, UK
Posts: 615
Blackplasma wrote ...
Don't walk into an airport with anything that resembles loose wires or veroboard; that's mostly what they tell staff to watch out for. Green double-sided PCBs, a silk-screened panel and you should be fine!
YMMV. Depends on the airport. Some are hopeless. At the airport of a major city of a neutral country in Europe, my wife had a professional chef's filleting knife in her handbag (she had just bought it - the town is famous for its knives) - she told the guy on the scanner about it so they could put it in the hold, and he just waved her through.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
I agree... I recently had to fly to Norway carrying a bunch of prototype circuit boards. I couldn't decide whether to put them in my hand luggage or the hold baggage. In the end I put them in a cardboard box in my hand luggage, and put the box on the X-ray along with my laptop for inspection.
Nobody cared. I think as regards electronics in your baggage, just don't pack anything that looks like a Hollywood b0mb! But if you needed some Internet guy to tell you that, you were probably a burden on society anyway
I've heard of people having trouble with kit that contained large capacitors. The X-ray may not be able to see through them, and they could be full of explosives, drugs, anything. People have been busted for smuggling drugs inside capacitors!
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
hmm.. interesting.
Wonder how many 4HV'ers are on one or more watch lists through no fault of their own? maybe we should start a protest group...
Chris Russell wrote ...
As for the watch, a 1N4007 will produce a small current in the presence of x-rays. Shouldn't be too hard to detect this current and trigger an alarm. Might be a challenge to string together enough of them to detect the relatively small amount of radiation, however. I also doubt anyone will let you borrow a backscatter machine to verify that your detector is working.
heh. You know those HV diodes are just a bunch of smaller diodes in series... :)
I'd expect the best ones to be obtained from old defunct triplers etc. Hook up to suitable amplifier, negatively bias them at a suitable voltage and voila.
I also wondered about using a visible detector and a long persistence phosphor such as ZnS with an infrared LED to "damp" remanent luminescence. This would be pretty accurate if combined with a thin pyrolytic graphite "sense plate" (as it can be sanded/cut down to sub mm thickness)
then there's the hacked mouse sensor idea...
As for testing it, I'd use a vacuum chamber (just scored a £20 bell jar and glass plate) and some Sellotape on a DC motor. Instant X-rays from 0.5 to 25 KeV with very little vacuum.
Registered Member #63
Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425
I'm firmly convinced that today's invasive airport security is out of control. As a result I'm really soured by stories of "I got my chefs' knives through security", or "I could have hidden drugs in my crutches and nobody checked!".
Nicko wrote ...
Some are hopeless [...] my wife had a professional chef's filleting knife in her handbag [...] and he just waved her through.
"Hopeless"? Nicko, do you mean you would prefer to be held up, a scene to be made, and attempt to argue through special provisions? I think in this situation you were blessed not to have an immature or a power-tripping guard.
Which is it? I thought we were tired of airport security being invasive and rude? Or do we want them to throw up a fuss and be anal and "not hopeless"? I ask, because if the process were any less "hopeless" than now, I guarantee you won't like it at all.
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