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'[PIC]:The Effect of Gamma Radiation on Man-in-the-'
2001\10\31@125205 by alice campbell

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This question is posted at the request of an offline member.

Will the irradiation of mail damage OTP and/or JW parts during shipping?  What else that we havent thought of might better be shipped by other carriers?

Alice
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2001\10\31@140022 by Batchellor, Gary

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As a repair technician of linear accelerators I can definitely say.. Maybe.
It depends on the exposure time and strength of the beam.
But it sure can't help.

{Original Message removed}

2001\10\31@143524 by Lawrence Lile

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I don't *THINK* radiation could do anything but erase these parts.  This
could be bad, in that the parts may come with an OSSCAL value programmed in,
which would be erased, preventing you from reading it before erasing it
yourself.

Now it takes a lot of radiation at the right frequency for a long time to
erase them - I would guess electron beams are more energetic than UV
radiation, so chances are it might work, but the dwell time should be very
short, which might make it not erase the parts.

Would an antistatic plastic bag stop electron beam radiation?  Surely a thin
aluminum bag, at most a lead bag would stop it.

Also radiation might affect seeds, human blood, live plants, film.

Meanwhile, the terrorists, who will think of this quickly, will simply wrap
their anthrax in the minimum amount of shielding it takes to stop the
radiation from working, after the US has wasted several billion dollars
trying to pretend we can be safe again.  Probably a layer of aluminum foil
would stop the radiation just fine, leaving the anthrax still active.  If
the mail stops working for them, they will find other simple ways of
delivering their deadly cargo - water supplies, crowds, air intakes in large
buildings, who knows?  We're not going to stop these desperadoes so easily,
and this whole program is a big waste of money.

--Lawrence


{Original Message removed}

2001\10\31@144950 by Thomas McGahee

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Modern x-ray machines used to examine items, such as those at airport
inspection stations use image intensifiers, and so the actual radiation
level is extremely small. It would not erase a PIC.

On the other hand, systems designed to irradiate items, such as those
used to irradiate flies are specifically designed to deliver
very high doseages in a short time. If this level of irradiation
is employed, then film will be exposed, and it is possible
that some erasure of PICs could be effected.

Fr. Thomas McGahee


{Original Message removed}


'[PIC]:The Effect of Gamma Radiation on Man-in-the-'
2001\11\01@064659 by Russell McMahon
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> Modern x-ray machines used to examine items, such as those at airport
> inspection stations use image intensifiers, and so the actual radiation
> level is extremely small. It would not erase a PIC.
>
> On the other hand, systems designed to irradiate items, such as those
> used to irradiate flies are specifically designed to deliver
> very high doseages in a short time. If this level of irradiation
> is employed, then film will be exposed, and it is possible
> that some erasure of PICs could be effected.


I agree.
But not in a controlled or necessarily useful manner alas.
Attempts have been made to erase OTP parts using radiation sources. I have
not heard of any successes. If there are any they are keeping it secret. I
understand that IC damage may occur at high enough radiation levels.

Radiation damages working ICs (hence "rad hard" parts) but I'm not sure of
the mechanism or what happens if there is no power applied.

Feeble attempt:
   I believe that in operation the radiation causes parasitic conduction
   across semiconductor layers that would not normally do so and can
   lead to immediate catastrophic failure.

Better attempt?
   Someone on this list will almost certainly have a better description
   of the actual mechanism.


       Russell McMahon

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2001\11\01@080648 by Jeff DeMaagd

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----- Original Message -----
From: Russell McMahon <.....apptechKILLspamspam@spam@CLEAR.NET.NZ>

> But not in a controlled or necessarily useful manner alas.
> Attempts have been made to erase OTP parts using radiation sources. I have
> not heard of any successes. If there are any they are keeping it secret. I
> understand that IC damage may occur at high enough radiation levels.
>
> Radiation damages working ICs (hence "rad hard" parts) but I'm not sure of
> the mechanism or what happens if there is no power applied.

I have a friend who swears the problems with his PalmPro started when
(clueless) airport security insisted that the device go through the X-ray
machine, that was about a year ago.  The problems were initially weird
crashes about once a week and it gradually got worse.  the Palm no longer
works as of half a year ago.  If it is true that X-rays can damage
electronic devices, is there any way to avoid being required to destroy a
perfectly good device should such a situation arise?  I think it was a
smaller airport that might not have dealt with electronic devices so often.

Jeff

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2001\11\01@083707 by Gerhard Fiedler

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At 22:26 11/01/2001 +1300, Russell McMahon wrote:
>But not in a controlled or necessarily useful manner alas.
>Attempts have been made to erase OTP parts using radiation sources. I have
>not heard of any successes.

I'm not sure the question here is so much whether it is possible to erase
parts. I think the relevant number would be the probability for altering a
single bit (or more) -- which is quite a different thing, IMO. (Besides the
possibility of damage to the circuit, of course.)


>Better attempt?
>     Someone on this list will almost certainly have a better description
>     of the actual mechanism.

This will have to wait for someone other than me... :)

ge

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2001\11\01@092707 by Dale Botkin

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On Thu, 1 Nov 2001, Jeff DeMaagd wrote:

> I have a friend who swears the problems with his PalmPro started when
> (clueless) airport security insisted that the device go through the X-ray
> machine, that was about a year ago.  The problems were initially weird
> crashes about once a week and it gradually got worse.  the Palm no longer
> works as of half a year ago.  If it is true that X-rays can damage
> electronic devices, is there any way to avoid being required to destroy a
> perfectly good device should such a situation arise?  I think it was a
> smaller airport that might not have dealt with electronic devices so often.

I have run my Palm V and laptop through many airport X-ray machines with
no ill effects, andI use both extensively every day.  I suspect your
friend's Palm problems are coincidental, though I wouldn't bet any large
sum on it.

Dale

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2001\11\01@150154 by Peter L. Peres

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> I don't *THINK* radiation could do anything but erase these parts.
> This could be bad, in that the parts may come with an OSSCAL value
> programmed in, which would be erased, preventing you from reading it
> before erasing it yourself.

Parts occasionally get broken permanently by strong X rays. Alpha may also
do them in, only better. Beta will not normally get through the chip case
but it may destroy the plastic in the process ;-). Even if they do not
cause permanent damage the radiation can generate charges in the gate
insulation or in the insulation wells of transistors that were not meant
to have that (and which cannot be erased by UV exposure because they are
buried in the structure). The result can be a device that acts strangely
or erratically.

> Now it takes a lot of radiation at the right frequency for a long time
> to erase them - I would guess electron beams are more energetic than
> UV radiation, so chances are it might work, but the dwell time should
> be very short, which might make it not erase the parts.

Electron beams do not get through and could cause very bad things to
happen to colors, plastic etc. If they're going to irradiate mail they'll
use X (or Gamma) or Alpha. Alpha is not such a good idea because it can
activate other materials. Neutrons even more so. X rays (and Gamma, which
are X rays that are even harder than X-rays) are more energetic than UV
and the most likely candidate. They are expensive to make in quantity
however.

> Would an antistatic plastic bag stop electron beam radiation?  Surely
> a thin aluminum bag, at most a lead bag would stop it.

An antistatic bag will stop only Beta (electrons) and weak Alpha
(protons), if thick enough. X rays will pass, so will neutrons.

> Also radiation might affect seeds, human blood, live plants, film.

Yes, and you should not send that in the mail unless specially marked and
by special ways.

I think that heating the mail to 120C for a few hours will do the trick
for biological substances at least. I wonder whether the glue and
thermoplastics used for various items will stand it.

Don't worry about shielding anything that is sent in the mail. If they see
an envelope that weighs as much as a phonebook then they'll know it is
moderately shielded ;-).

Peter

PS: I am not an expert on this but I did my homework.

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2001\11\02@072405 by Alan B. Pearce

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>But not in a controlled or necessarily useful manner alas.
>Attempts have been made to erase OTP parts using radiation sources. I have
>not heard of any successes. If there are any they are keeping it secret. I
>understand that IC damage may occur at high enough radiation levels.

It is possible to erase chips using X-Rays, but I do not know about electron
beam bombardment. I remember going to a Nelcon lecture in the 1970's where
the presenter described using an 8080 micro on a simulator for medical
students to use an x-ray machine on a manikin, and see "internal body parts"
moving as it breathed - you obviously do not want a real human under the
x-rays for an unknown long length of time. Apparently this all worked fine
for some time, but then there were sporadic movements occurring at
irregular, but increasingly often intervals. It turned out the x-rays were
erasing the EPROM's used. The solution was to use bipolar fusible link
proms.

To increase the radiation hardness of chips being installed in space
instrumentation where the chip and package combination is not at a suitable
RH level, we glue tantalum sheet to the top of the package. Apparently this
has the best weight/RH resistance combination to do this.

As an aside apparently devices made with geometries 0.25 micron and finer
are intrinsically RH to high levels of radiation.

Also there are RH EPROM's available, as some of my colleagues are using
these. However many control systems now use RH EEProms as the program space
for their microcontrollers, so that the code can be updated from the ground.

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2001\11\05@145427 by Alan Shinn

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O.K. - enough is enough! What the heck does any of this have to do with Marigolds?
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