Marc wrote:
>
> > Just an idea ... got an airport reasonabley nearby?  Try making an
> > appointment with the head of airport security, and explain to him as exactly
>
> That's a good suggestion, I'll try to do that.
>
> Still I am concerned that the machines might work in pulsed mode, rendering
> the result of any empirical tests useless.
>
> My design currently makes 2 measurements per second, and the setup time for the
> PIC ADC is (much) less than 100us.  If the XRAY is pulsed at 1 Hz for example,
> the probability that it hits my 2/10000th second window is very low.  In fact,
> in this szenario and when my design happens to be vulnerable to the X-RAY, I have
> a good chance of spending a whole hour running it through the X-RAY back and forth
> without recording a single trigger.
>
> I need some basic understanding of the inner workings of the X-RAY to establish
> a test environment that does (100%) lay the fault open (if it exists).
>
> I assume that X-RAY is pulsed because I think that continous radiation is more
> dangerous but doesn't improve the security of the airport, and because I recall
> having seen still-images on the terminal screens a couple of times.

I ran this past my father (an EE) and he suggested a reference detector
(encapsulated epoxy, or metal box) that will NEVER see visible light
then you could have code that if the reference saw something and the
regular sensor saw something then it was OK otherwise log the tamper..
w/ a 2 Hz detector reading that wouldn't be much time for the vandal to
open up BOTH sensors..


                Damon Hopkins