Re: shielding for Sr90 sealed source

["Bob Westerdale" <Bob.Westerdale@ametek.com>]

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