[ RadSafe ] Lethal Amount of Po-210 - any gamma?

Wed Dec 13 10:31:41 CST 2006

It turned out to be radioactive material in cargo and, yes, I tried to do a 
(discrete) gamma survey. It was not obviously coming from the cargo area. My 
theory is that there were different materials between the source and the 
detector that influenced the dose rate and that made it difficult to zero in 
on the source location.

Below is part of my response to Jim, describing some of the other things I 
tried. (Just in case the original message got stuck in the radsafe servers 
and you didn't see it):

...It turned out to be radioactive material in cargo. I was under the
(apparently mistaken) impression that radioactive material was not supposed
to go on passenger planes. Otherwise, I would have asked the pilot right
away.

I considered a bunch of alternative explanations, but was able to eliminate
most of them: I waited until every one else got off the plane, to make sure
the reading was not originating from one of the passengers. I made sure the
reading returned to normal as soon as I got off the plane to eliminate the
possibility of equipment failure ...

Regards,
Kai

----- Original Message ----- 
From: "Flanigan, Floyd" <Floyd.Flanigan at nmcco.com>
To: "Kai Kaletsch" <eic at shaw.ca>; <radsafe at radlab.nl>
Sent: Wednesday, December 13, 2006 10:06 AM
Subject: RE: [ RadSafe ] Lethal Amount of Po-210 - any gamma?

I sent another response right after that one referring to the possibility of 
your being seated near a patient who'd been administered a 
radiopharmaceutical. Did you have a chance to get up and do a sweep of the 
general area and if so, were there concentric variations or was the 
distribution relatively uniform?
I apologize for the altitude reply. I mis-read your post and thought you 
were saying that the dose rate remained the same pre-flight and 
post-landing. My mistake.

Floyd

-----Original Message-----
From: Kai Kaletsch [mailto:eic at shaw.ca]
Sent: Wednesday, December 13, 2006 9:54 AM
To: Flanigan, Floyd; radsafe at radlab.nl
Subject: Re: [ RadSafe ] Lethal Amount of Po-210 - any gamma?

Hi Floyd,

Now that you mention it, there was a correlation with altitude: As altitude
decreased by a few meters between departure gate and plane, dose rate
increased by a factor of 10. As altitude increased, going from the plane to
the arrival gate, dose rate decreased by 90%. Maybe we can blame the uranium
at the center of the earth :).

Joking aside, did you see my responses to Franz and Jim?  Does that explain
things?

Regards,
Kai

----- Original Message ----- 
From: "Flanigan, Floyd" <Floyd.Flanigan at nmcco.com>
To: "Franz Schönhofer" <franz.schoenhofer at chello.at>; "Kai Kaletsch"
<eic at shaw.ca>; <radsafe at radlab.nl>
Sent: Wednesday, December 13, 2006 2:11 AM
Subject: RE: [ RadSafe ] Lethal Amount of Po-210 - any gamma?

Kai,
Did the increase in detected levels, by chance, increase in conjunction with
altitude and decrease with the lack there-of? If so, Franz is correct. You
were picking up the increase in background radiation levels produced by
cosmic rays.

Floyd W. Flanigan B.S.Nuc.H.P.

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf
Of Franz Schönhofer
Sent: Tuesday, December 12, 2006 2:17 PM
To: 'Kai Kaletsch'; radsafe at radlab.nl
Subject: AW: [ RadSafe ] Lethal Amount of Po-210 - any gamma?

Ever heard about cosmic rays???????!!!!!!!

Franz Schoenhofer
PhD, MR iR
Habicherg. 31/7
A-1160 Vienna
AUSTRIA
phone -43-0699-1168-1319

> -----Ursprüngliche Nachricht-----
> Von: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] Im
> Auftrag von Kai Kaletsch
> Gesendet: Montag, 11. Dezember 2006 16:13
> An: radsafe at radlab.nl
> Betreff: [ RadSafe ] Lethal Amount of Po-210 - any gamma?
>
> Po-210 emits a gamma ray, but at a very low branching ratio. I did a quick
> calculation and concluded that you would not be able to see a gamma field
> above background, even a very small distance away from a lethal dose of
> Po-210, or even a few tens of lethal doses of Po-210 (it doesn't seem like
> those guys were particularly stingy with the stuff).
>
> I would appreciate it if anyone in radsafe land could tell me if this
> conclusion is correct.
>
> History:
>
> I was on a plane yesterday and noticed elevated gamma readings on my
> radiation detecting watch. (5 to 20 times normal BG before take-off and
> after landing and noticeably higher than what I am used to during flight.)
> Was told afterward that there were medical isotopes in cargo. But, you
> have
> a lot of time to consider possible scenarios during a 4 hour flight.
>
> BTW, it's a pretty strange experience trying to tell an airline that their
> plane is radioactive. You don't know who to talk to and you are not sure
> if
> they are going to stick you in a straight jacket. Especially, at a time
> when
> all you hear on the news is about people getting killed with radiation and
> planes getting contaminated. The first few people you talk to do not know
> that there is radioactive material in cargo.
>
> Kai
>
>
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