[ RadSafe ] Hot particles on automobile air filters

[Busby, Chris]

-----Original Message-----
From: radsafe-bounces at agni.phys.iit.edu on behalf of kmcheng1 at netvigator.com
Sent: Thu 23/06/2011 22:29
To: The International Radiation Protection (Health Physics) Mailing	List; The International Radiation Protection (Health Physics)	MailingList
Subject: Re: [ RadSafe ] Hot particles on automobile air filters
 
A simple demonstration we used to show to junior school students about natural radioactivity was to cover the nozzle of a vacuum cleaner with a filter paper, turn on the cleaner for 5 to 10 minutes and then put the filter paper in front of a GM counter.  There were normally sufficient radon progeny on the filter paper to give a significant count rate above the background.  The same would be expected on an automobile air filter shortly after it is taken out of a running engine.

That is probably nothing new, unless the gamma spectrum shows that there are something else other than radon progeny.

Clement Cheng
Radiation Health Unit
Department of Health
Hong Kong SAR, China


> 
> ???: "Brennan, Mike  (DOH)" <Mike.Brennan at DOH.WA.GOV>
> ??: 2011/06/24 ??? ?? 03:29:24 HKT
> ???: "The International Radiation Protection (Health Physics) MailingList"
> 	<radsafe at agni.phys.iit.edu>
> ??: Re: [ RadSafe ] Hot particles on automobile air filters
> 
> Ah, so the data is robust enough to share with friends, so they can
> spread the news worldwide, but not robust enough to expose to
> potentially critical examination.  
> 
> How very, very, usual.
> 
> >Sorry, Its not my data and you will have to wait for it to be
> published. It was meaursed in the USA by a colleague. I do however have
> my own data and will share it with you in due course. 
> Sincerely
> Chris 
> 
> Sinecerly
> Chris
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But these filters have been across the Pacific and in the mail system for a long time. The gamma spectrum of the filters shows Cs137 and I131. What you say is that the particles in the filters are hot (register as splashes on Xray film) becasue of radon daughters? yes?
Chris