re[2]: shielding for Sr90 sealed source

[Harry Newman <hresources@NEXTEP.CC>]

Consider using MCNP.



Regards,

Harry



Harry J. Newman, CHP

NEXTEP Environmental, Inc.

808 Lyndon Lane, Suite 201

Louisville, KY  40222

502-339-9767 office

502-339-9275 fax

hnewman@nextep.cc







  >>  I'm mulling over the design of a

  >>   holder for a sealed Sr-90 2 mCi

  >>   source. 

  >>  This beta emitter ( about .5 Mev)

  >>   decays to Y-90 (2.3 Mev)  and

  >>   creates 

  >>  some significant , energetic

  >>   Bremmstrahlung whenever it

  >>   impacts higher 

  >>  atomic # materials,  for instance

  >>   the end of the detector I'm

  >>   irradiating. 

  >>    The source vendor has advised me

  >>   to shield the betas wherever

  >>   possible, 

  >>  with 10-20 cm of acrylic,  but I'm

  >>   troubled by the rather energetic   >>  scatter-  whose energy will be a

  >>   continuum from approximately 2.3

  >>   Mev and 

  >>  down....    Our calculations say

  >>   that about 2" of lead will bring

  >>   this 

  >>  down to a couple of mR/hr,   but 

  >>   I thought  perhaps someone has

  >>   had some 

  >>  previous experience with this

  >>   situation.   I already have

  >>   enough doorstops 

  >>  and paperweights to remind me of

  >>   the perils of "rushing to

  >>   production"!

  >>  thanks in advance,

  >>          Bob Westerdale

  >>   

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