RE: Sky Shine

[Gerald.P.Lahti@ucm.com]

Remember gamma rays which undergo Compton scatter lose energy; the limiting
case of backscatter  (180 degree scatter) results in a 0.25 MeV (or less)
gamma ray regardless of initial energy.  (see Figure I of NBS Circular 542,
for example).  So, you may be dealing with gammas of low energy (and easy to
shield) at the detector, but higher energy (harder to shield) at the source.

* * * * * * * * * * * * * * * * * *
Jerry Lahti
Radiological Saferty Specialist
ComEd - Downers Grove
(630) 663-6659
gerald.p.lahti@ucm.com
* * * * * * * * * * * * * * * * * * 

> -----Original Message-----
> From:	Dave Biela [SMTP:BielaD@wv.doe.gov]
> Sent:	Thursday, April 27, 2000 11:29 AM
> To:	Multiple recipients of list
> Subject:	Sky Shine
> 
> I have a question dealing with Sky Shine.  
> 
> If I know that (AT THE DOSE POINT LOCATION) it takes 1/4 inch of steel to
> get me to a level I can live with (Steel placed around the detector to
> determine this), can I shield the source (Like with NORMAL shielding
> situations) with a 1/4 inch of steel or do I have to shield somewhere
> after the Compton interaction with the air.  I feel that all the same
> shielding principles apply and I could shield at the source, but I do not
> deal with Sky Shine enough to be sure.
> 
> You can send information directly to me:
> 
> BielaD@wv.doe.gov
> 716-942-4423
> 
> or respond over RADSAFE, this could be interesting data to more then me.
> 
> Thanks
> Dave Biela
>  
> 
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html


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