Re: cherenkov radiation

["J.J. Rozental" <rozental@unisys.com.br>]

On 3 September 1987, a shielded, strongly radioactive caesium-137 source
(50.9 TBq, or 1375 Ci, at the time) was removed from its protective housing
in a teletherapy machine in an abandoned clinic in Goiania, Brazil, and
subsequently ruptured. The radioactive source was in the form of cesium
chloride salt, which is highly soluble and readily dispersible.

After the source capsule was ruptured, the remnants of the source were sold
for scrap to a junkyard owner. He noticed that the source material glowed
blue in the dark, and over a period of days friends and relatives come and
saw the phenomenon, fascinated. Fragments of the source the sizes of rice
grains were distributed to several families attracted by the
glow-in-the-dark radioactive caesium chloride salt ...Thus began one of the
most serious radiological accidents ever to have occurred.

In USA, this Charenkov effect was studied by the REAC/TS Director Robert
Ricks.

Jose Julio Rozental
rozental@unisys.com.br
Rio de Janeiro, Brazil
until november 15/2000

----- Original Message -----
From: Minnema, Douglas <Douglas.Minnema@ns.doe.gov>
To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
Sent: Thursday, November 09, 2000 5:49 PM
Subject: RE: cherenkov radiation


> Brian and others,
>
> I agree about the cameras, we had the same problem at our fast burst
reactor
> at Sandia.  However, there are easier ways to check.  A large Co-60 source
> will glow nicely in water from the same phenomenon, but I don't believe
that
> there is anything observed in air.
>
> On the other hand, I have personally seen a blue glow from high energy,
high
> intensity pulsed electron beams in air (10 MeV and 10 kA are the numbers I
> recall) when we fired an electron accelerator outdoors after dark.  (No,
the
> beam was not directed into our eyes, and yes, we were a safe distance away
> :-) We also captured it on polaroid film.  It was sort of like a faint
> lightning bolt, and clearly followed the path of the beam.
>
> Interesting, thought.  As long as I have been hearing these discussions, I
> had never put the two experiences together.  Perhaps there is something to
> the claims after all.
>
> As you stated, when you throw out E16 - E17 neutrons (and all the
associated
> photons and electrons) much of what you expect does not apply.
>
> Doug Minnema, PhD, CHP
> Defense Programs
>
> what few thoughts i have are  truly my own ...
>
> > -----Original Message-----
> > From: Brian Rees [SMTP:brees@lanl.gov]
> > Sent: Thursday, November 09, 2000 1:32 PM
> > To: Multiple recipients of list
> > Subject: Re: cherenkov radiation
> >
> > I can tell you from personal experience that a video camera will not
show
> > a
> > blue flash, the instantaneous dose rate during the excursion overwhelms
> > the
> > camera.  The picture doesn't recover for a good 10-15 seconds.  Yes,
it's
> > a
> > rad-hard camera.  Yes it's a ways away.  When you throw out E16 -E17
> > neutrons in a few microseconds much of what you expect doesn't apply.
> >
> >
>
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