[ RadSafe ] Encounter with Caldicott and Gundersen on KGO Radio

[Mark Ramsay]

Sky shine is a well known issue in open top radiography bays.

It's actually amazing what you measure on the 'safe' side of a shielding wall when a large activity Ir-192 source is placed on the unsafe side at or near ground level. Move away from the wall and higher and you will find it 'peaks' before falling back again (clearly this is influenced by many things).

If you think about it - consider light photons. Place a high powered torch facing downwards inside an open top radiography bay, 1m from the ground. Let the walls be say 3m high. Now black out the room containing the radiography bay. Switch the torch on and crouch very near the outer shielding wall at near ground level. What do you see - very little (might not even see your hands if you have made the room dark enough).

Now stand up and move away - what do you see. Not direct light (of course) but you might just be able to make out your hands ....

Rgs

Mark


-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Chris Alston
Sent: 16 April 2012 15:49
To: The International Radiation Protection (Health Physics) Mailing List
Subject: Re: [ RadSafe ] Encounter with Caldicott and Gundersen on KGO Radio

Roger

I cannot speak directly to whatever Gundersen is talking about, but "skyshine" is just radiation which has been scattered back down, by the atmosphere, which originated in a relatively intense source at or near ground-level.  I think that there was a well-known instance of this phenomenon at Brookhaven, many years ago, involving (I think) a Cs source with which they were experimentally irradiating trees.
However, please do *not* quote me.  You might try Googling it.

Cheers
cja


---------- Forwarded message ----------
From: Roger Helbig <rwhelbig at gmail.com>
Date: Mon, Apr 16, 2012 at 4:49 AM
Subject: [ RadSafe ] Encounter with Dr Helen Caldicott and Arnie Gundersen on KGO Radio
To: RADSAFE <radsafe at health.phys.iit.edu>


Kallie Metzger is the hero of the week.
http://nuclearliteracy.org/nuclear-all-stars/kallie/
Wouldn't it be good if more people went to these kinds of meetings and questioned the dogma preached by Caldicott and others?

I did not hear anyone question Gundersen, all of the callers to the Pat Thurston program (5PM-6PM was the actual time that Gundersen was on the program) were anti-nuclear power fanatics who seemed to have worshipped the ground Gundersen walked on.

As I mentioned before, anyone can download and listen to the interview.  I am very certain that Gundersen lied about his own background along with making up science along the way.  His concept of gamma radiation reflecting off the atmosphere as "deadly skyshine"
seemed quite far out.  I did not think that anything reflected gamma radiation.

www.kgoradio.com, Listen, Hourly Archives, Sunday, 5-6PM (I will also be able to send the audio file to anyone who e-mails me and asks for
it) - I will transcribe this to some degree; it is really hard to do since I do not take dictation!
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