Re: go interceptors!

From: Robert J. Bradbury (
Date: Mon Jul 16 2001 - 19:34:26 MDT

Mike Lorrey wrote (quoting someone???):
> > Now, a true pony nuke is about 80 lb, and has a yeild of abour 8kt. It
> > also is sniffed when it comes into the country, and a radiation source
> > would glow like a neon sign in an xray machine.


> For starters, an xray machine is going to see the materials of a nuclear
> device, as well as a vaporous cloud on the screen from the radiation
> from the isotopes.

Mike, I have to call you on this, because it *may* be one of those
classical examples where you extrapolating from what you know to
what you think you know (I'm obviously guilty of this as well as
a recent exchange with Harvey showed). But playing list-cop,
I'm not going to let you slide by *that* easily.

A discussion of Reactor & Weapons grade materials:

seems to indicate the main elements in weapons are either U-235 or Pu-238.
A quick examination of my Handbook of Chemistry and Physics, 72nd Ed.,
pgs 11-28 to 11-131 (Table of Isotopes) seems to suggest that those two
isotopes only decay by alpha particle (He++) emissions which are easily
blocked from detectors. The remainder of the decay energy balance
seems to produce x-rays or gamma-rays, so two questions arise:

(a) Are X-ray machine detectors sensitive to the X-ray energy frequencies
    produced by such decays? (I've taken a course in CCD detectors
    and their sensitivity to X-rays is X-ray frequency dependent
    if I recall correctly.) Also, this article:
    seems to suggest that there are at least 4 different types
    of X-ray detectors in common use.
(b) Are the decays of a few kg of radioactive material sufficiently
    frequent to produce a "vaporous cloud" on the screen as you suggest
    (when compared to the X-rays that the X-ray machine itself must be

In short,
  - do you know the physics and devices involved in your statement?;
  - or have you seen them in action to be true?;
  - or have you heard your claims from a reliable source?
[Anything else is an extrapolation and of questionable value.]

You, like I, have a love of rhetorical debate, however if we are to
contribute to the list productively we have to bury the pleasure
of "Jumping up and down on someone, yelling at the top of our
lungs, KILL, KILL, KILL" and instead substitute it with a Joe
Friday mentality of "Just the facts Maaam, just the facts".

Now, your comments may be completely accurate, and if so, I'd like
to know whether or not X-ray machines have been specifically designed
to allow the detection of radioactive materials (or whether this is
just fortuitous circumstance). Note that I'm not disputing your general
position, as I've had my computer carry-on sniffed a number of times over
the last couple of years for "plastique". I have no doubt that surveys
for dangerous materials do occur, and that attempts to detect radioactive
materials or unusual explosive signatures does take place. Things are going
to get pretty dicey however when the detection needs to recognize
particles that carry signatures that are extraordinarily close to
the bacteria present in our saliva.


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