Re: shielding for 86-Rb

[Les Fraley <les@lamar.ColoState.EDU>]

On Tue, 12 Nov 1996, baumbaug@nosc.mil wrote:

>         Rhonda,
> 
>         From my personal past experience, this is one of the times that you
> need both types of shielding.  Rb-86 has some "big boy" betas (one almost 2
> MeV) that could produce some pretty hefty bremstrahlung x-rays using Pb
> alone, AND some big boy gamma photons (1.8 MeV) as well.  In addition there
> are a lot of cascading x-rays produced internally, so its pretty messy to
> work with (exposure-wise)unless you use due caution.

  1.08 MeV, 8.8 % of the time, not 1.8 MeV.

> 
>         Put the plexiglas between your source and the lead - and your
> researcher.  This will help shield against the betas and you won't be
> producing as many nor as strong (MeV wise) x-rays.  Most of those produced
> will (hopefully) be attenuated by the Pb.  I think that you'll need more
> than "just" lead sheets that are so popular now-a-days (usually 0.030"
> thick).  For 1 mCi you may need a couple-three of thickness' of Pb sheets or
> Pb bricks.  
> 
>         P.S. Remember to have your researcher shield the rest of the lab
> from his experiment, not only himself!!
> 
>         P.P.S.  Like P-32, Rb-86 tends to migrate around the lab area by
> "sticking" to everything (especially rubber and some plastics), however,
> like P-32, using a survey meter it is "easily" detected.
> 
> 
>         Hope this helps,
> 
>         Joel  Baumbaugh
> 
> 
> 
>         Std. Disclaimer.  The opinion above are (not necessarily) those of
> my employer, but are mine alone.
> 
> 
> 
> 
> At 12:12 PM 11/12/96 -0600, you wrote:
> >    I am not a health physicist, and so am seeking the help of those on this
> >list who may have experience working with isotopes that are both beta and gamma
> >emitters.  I would like to know what sort of shielding is appropriate for
> >someone working with around 1mCi of 86-Rb in a research lab situation.  
> >    The advice I have been giving is to treat it like a pure beta emitter and
> >use plexiglass for primary shielding, since most of the emissions are betas. 
> >However, the user plans to treat it like a gamma emitter and use lead (i.e.
> lead
> >shielding around the source, wearing a lead apron).  Is the best solution
> to use
> >plexiglass as a primary shield with lead as a secondary shield?  Any help will
> >be appreciated!
> >
> >Rhonda O'Keefe
> >rhonda_okeefe@cambneuro.com
> >
> >
> >
> Joel T. Baumbaugh (baumbaug@nosc.mil)
> Naval Research and Development (NRaD)
> San Diego, CA., U.S.A.
> 
>