Ooops...TSA to retest airport body scanners for radiation

[TechMan]

http://www.usatoday.com/news/washington/2011-03-11-tsa-scans_N.htm

The Transportation Security Administration announced Friday that it would retest every full-body X-ray scanner that emits ionizing radiation — 247 machines at 38 airports — after maintenance records on some of the devices showed radiation levels 10 times higher than expected.

The TSA says that the records reflect math mistakes and that all the machines are safe. Indeed, even the highest readings listed on some of the records — the numbers that the TSA says were mistakes — appear to be many times less than what the agency says a person absorbs through one day of natural background radiation.

Ya, like I would really believe the TSA. 

[French G.]

I'm sure they hire only highly qualified radiography techs and pay them well...

[vaskidmark]

I'm sure they hire only highly qualified radiography techs and pay them well...

I'm from the governmentand I'm here to help you.

Relax, what could go wrong?

Was I supposed to cut the red wire or the yellow wire?

Which of the above worries you the most?

stay safe.

[TommyGunn]

I'm from the governmentand I'm here to help you.

Relax, what could go wrong?

Was I supposed to cut the red wire or the yellow wire?

It was the GREEN wire!!!!

[erictank]

It was the GREEN wire!!!!

No, you were supposed to grab the whole bundle of wires and just yank that sucker out at the 1-second-to-detonation mark.

[RevDisk]

No, you were supposed to grab the whole bundle of wires and just yank that sucker out at the 1-second-to-detonation mark.

I suppose a Hall Effect Current Sensor, or just a multimeter, would be too lacking in drama.   

[kgbsquirrel]

I suppose a Hall Effect Current Sensor, or just a multimeter, would be too lacking in drama.   

Or just clipping all the detonator leads.

[S. Williamson]

Which is why, from the very first "tense" movie-bomb scene I'd watched as a kid, I've wondered why the hell they didn't make all the wires one color. 

[RevDisk]

Or just clipping all the detonator leads.

Because I'm paranoid that someone would stick in a battery or capacitors at the detonator and rig the thing to blow when voltage dropped to the 'detonator'.  Overkill for a roadside IED, sure.  Not so much for a bomb someone expects an EOD team to defuse and really wants to make sure the thing detonates.  There's a reason why folks prefer to blow in place.

I generally don't cut wires without being very very sure there's no current running through the thing.  Buddy of mine has a set of snips with two circles burned through them.   Yea, he snipped both instead of one at a time.  Why I have no clue. 

[kgbsquirrel]

Because I'm paranoid that someone would stick in a battery or capacitors at the detonator and rig the thing to blow when voltage dropped to the 'detonator'.  Overkill for a roadside IED, sure.  Not so much for a bomb someone expects an EOD team to defuse and really wants to make sure the thing detonates.  There's a reason why folks prefer to blow in place.

I generally don't cut wires without being very very sure there's no current running through the thing.  Buddy of mine has a set of snips with two circles burned through them.   Yea, he snipped both instead of one at a time.  Why I have no clue. 

Electric detonators (blasting caps) are set off by applying a current to them. There is no "constant current" that if removed will cause it to explode. By cutting the wire leads, you prevent any current from ever reaching the cap and setting it off.

http://en.wikipedia.org/wiki/Blasting_cap

[cassandra and sara's daddy]

but hook this lil baby to the circuit and tie the test circuit into a secondary detonator and cutting wires is very bad
http://www.blasterstool.com/buzz-boxbb75.aspx

shoot got a real mean streak?  enclose in in the shaped charge along with one cap wired to it  be one you'd send someone you owe money to to arm but no fun to work on once armed. i think new batteries would be a must too.

[kgbsquirrel]

but hook this lil baby to the circuit and tie the test circuit into a secondary detonator and cutting wires is very bad
http://www.blasterstool.com/buzz-boxbb75.aspx

shoot got a real mean streak?  enclose in in the shaped charge along with one cap wired to it  be one you'd send someone you owe money to to arm but no fun to work on once armed. i think new batteries would be a must too.

How do you plan on keeping that secondary detonator from exploding when you arm the device?  Scratch that, looked at that little tester, very handy, and for some reason I thought you meant a second blasting cap, not a second circuit control device.

But then again, I'm more of a bastard in that if I wished a device to be anti-tamper it would be the following, A: it would be inside a black cardboard box with UV, IR, and Vis light sensing diodes, and B: looots of mercury switches. Go ahead, nudge that box.  

P.S. X-ray sensor too.

[cassandra and sara's daddy]

gotta arm them separately, and hopefully in the right order. though if you screw up no one will say i told you so.i think if you like yourself you'd first bring the tester online let it settle down then link in the secondary circuit. course if a feller felt real lucky he could do it all at once.  so i guess it would really be a three step process. smarter guy than me could do something cuter but for the last one i'd use a version of the clothes pin or mousetrap.  something real simple and mechanical rather than high tech. with a default closed position held open with a non conductor. get good results on first 2 stages pull the string and mechanically close last arming circuit.  how long a string you use is a testimony as to your faith in your own work and/or an indicator of how smart you are. either way i bet you hold your breath for a second waiting for the loud noise the first couple times

[RevDisk]

Electric detonators (blasting caps) are set off by applying a current to them. There is no "constant current" that if removed will cause it to explode. By cutting the wire leads, you prevent any current from ever reaching the cap and setting it off.

http://en.wikipedia.org/wiki/Blasting_cap

Yes, I'm slightly familiar with them.  That's why I put one reference to detonator in quote marks, and the other not.  Anti-tamper devices or techniques were not exactly common, but they're not exactly unheard of either.  I apologize if I failed to clearly state myself.

Folks on occasion practice ways of killing not just the stupid folks, but the smart ones as well.  Back in the Balkans, you'd occasionally see odd bits of creativity.  Like a much smaller landmine under a semi-obvious anti-tank mine.  More than one person got nailed that way.   Couple of my buddies in Iraq have seen some half-hearted anti-tamper techniques, more or less aimed at killing the folks that try to dispose of explosives. 

The point isn't really to kill the EOD folks (relatively few IEDs, percentage wise, are disposed of by EOD), it's to make folks move slightly slower and be more cautious.  Killing someone slightly smarter or theoretically more lucky than norm is just a bonus.

[cassandra and sara's daddy]

i learned quite a bit of my better living through modern chemistry from a eod guy who had a weird background and a truly perverse nature. he liked "puzzles" and he thought it was great fund to build lil toys to bobby trap a room with or after a while just to watch me try to figure em out.  his idea of cute would be to rig one that if you failed would set of a noisemaker behind you remotely. or to rig the door to a room or a drawer on a desk .  strange strange man  lots of fun to party with though

[kgbsquirrel]

Yes, I'm slightly familiar with them.  That's why I put one reference to detonator in quote marks, and the other not.  Anti-tamper devices or techniques were not exactly common, but they're not exactly unheard of either.  I apologize if I failed to clearly state myself.

Folks on occasion practice ways of killing not just the stupid folks, but the smart ones as well.  Back in the Balkans, you'd occasionally see odd bits of creativity.  Like a much smaller landmine under a semi-obvious anti-tank mine.  More than one person got nailed that way.   Couple of my buddies in Iraq have seen some half-hearted anti-tamper techniques, more or less aimed at killing the folks that try to dispose of explosives. 

The point isn't really to kill the EOD folks (relatively few IEDs, percentage wise, are disposed of by EOD), it's to make folks move slightly slower and be more cautious.  Killing someone slightly smarter or theoretically more lucky than norm is just a bonus.

One of my VFW friends got to play that Darwinian game in Vietnam. They had claymores rigged on the perimeter of their bases or camps and wired to a clacker that the guy on watch had. Charlie would sneak in quietly, turn the claymore around, sneak back a ways and then make an obvious noise. When the guy on watch poked his head up and hit the clacker he would take himself out. My friend's solution was to cannibalize thermostats for their mercury switch and rig them to his claymores as an anti-tamper device. When charlie came back in the middle of the pitch black night and started messing with the claymore, ka-boom.

[cassandra and sara's daddy]

means you have to be the one to run perimeter checks after that or at least warn the folks that did em

[RevDisk]

How do you plan on keeping that secondary detonator from exploding when you arm the device?  Scratch that, looked at that little tester, very handy, and for some reason I thought you meant a second blasting cap, not a second circuit control device.

But then again, I'm more of a bastard in that if I wished a device to be anti-tamper it would be the following, A: it would be inside a black cardboard box with UV, IR, and Vis light sensing diodes, and B: looots of mercury switches. Go ahead, nudge that box.  

P.S. X-ray sensor too.

I've heard of overpressuring the container with nitrogen (or whatever) and putting in a pressure sensor, putting photosensors inside material that should never be exposed to light (like inside the sides of a container or inside a chip), using capacitors as dead man's switch, etc.  If you really want to be sure, I wouldn't use mercury switches.  An accelerometer is a bit more expensive and generally not readily available, but immune to dry ice. 

If you want to be the most evil **** on the planet, don't include an x-ray sensor.  Use Delrin (sp?) and/or other x-ray transparent material.  :)

You'd probably just end up killing a robot, but you'd become a celebrity to the EOD community overnight.

I kinda blinked when I watched Law Abiding Citizen.  Dude used an iPhone as the detonation controller.    He didn't bother to use the build in accelerometer to prevent tampering.  I was very "WTF?" 

One of my VFW friends got to play that Darwinian game in Vietnam. They had claymores rigged on the perimeter of their bases or camps and wired to a clacker that the guy on watch had. Charlie would sneak in quietly, turn the claymore around, sneak back a ways and then make an obvious noise. When the guy on watch poked his head up and hit the clacker he would take himself out. My friend's solution was to cannibalize thermostats for their mercury switch and rig them to his claymores as an anti-tamper device. When charlie came back in the middle of the pitch black night and started messing with the claymore, ka-boom.

Ayep.  Exploding in place or hitting it with a water cannon is honestly the best solution.  Screw messing around with defusing a bomb.