[HH] X-ray machines & mobile electronics

[Greg London]

I turn off electronics before putting them through xray.

> would like to understand better the failure mode.

I worked on satelite electronics designs for some years
in a previous life. I don't know which kind of radiation
causes which specific damage. But we had to design for
flip-flops spontaneously switching from 1-to-0 and 0-to-1,
as well as any single transistor becoming either a short or open.

You might have a gate temporarily short to ground and
burn out a wire, or bidirectional busses might momentarily
have multiple drivers pushing to different logic levels and
burn one or the other out.

That's at the bit or gate level. How that failure mode looks
at the system level is anyone's guess. it could be anything
from "need to soft reset" to "cycle power" to
"melted slag, try system 2"


But if the device is off when the radiation hits it,
then you can't get any of that sort of behavior or failures.
If there is no power to the system, then a flip or a short or
whatever can't cause a current surge and burn out one of the
metal layers tying the gates together.

Greg



> It would be tempting to try to find some inexpensive dosimeters an attach
> them
> to your checked luggage.  Once they pass through, put them in shielded
> envelopes
> and have them read.
>
> Even better, a small DIY recording geiger-mueller counter you could
> use and re-use,
> if it was small enough to put through in your luggage/bags too.  Recording
> so it
> can be read later!
>
>
> On Tue, Feb 25, 2014 at 5:27 AM, Bill Bogstad <bogstad at pobox.com> wrote:
>> This is slightly off-topic, but might be relevant to those of us who
>> like to travel with
>> our gadgets.
>>
>> I just got back from a trip to Spain with my family and had some very
>> bad luck with consumer electronics.   I had two cellphones and an HP
>> Touchpad tablet stop
>> working during my trip.   The cellphones were new/cheap unlocked GSM
>> phones
>> that I had specifically purchased to use with pre-paid SIMs in Spain.
>>  I bought the Touchpad new when HP had their fire sale back in 2011.
>> The only event that I can think of that would explain the sudden
>> failures is that they all went through security (X-ray) scanning
>> machines between when they were last working and when I noticed they
>> had failed (a couple of hours at most).   One of the cell phones & the
>> Touchpad went through a scanner at a museum. The other (identical
>> model) cell phone went through a scanner at a train station.  All of
>> the devices claim to be charging when I connect them to their chargers
>> (including on-screen displays/animations) but never work.   The cell
>> phones eventually claim to be fully charged, but won't turn on.   The
>> Touchpad stays on the "emergency charge" screen and never boots.
>>
>> Has anybody else had similar experiences?   Any ideas on why the
>> devices claim to charge, but won't boot/turn on?   I'm pretty much
>> resigned to the fact that they
>> are all now headed for recycling but would like to understand better
>> the failure mode.
>>
>> Thanks,
>> Bill Bogstad
>> _______________________________________________
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>> Hardwarehacking at blu.org
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>
>
>
> --
>><> ... Jack
>
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> "If you are not part of the solution, you are part of the precipitate"
> - Henry J. Tillman
> "Anyone who has never made a mistake, has never tried anything new." -
> Albert Einstein
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> Admiral Grace Hopper, USN
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