PuBe source

["Deborah P. Steva" <dps3c@watt.seas.virginia.edu>]

Dear Radsafe-

When people work with a PuBe source, they are primarily
concerned with the neutrons emitted (from a radiation
protection standpoint.)  The Pu-239 in the source emits some
low energy gammas (Kocher says 173 weak gammas) and a 13.6 keV
X-ray (4.4%) which are rather insignificant in terms of dose.
There is also a gamma ray of energy 4.43 MeV emitted as the
C-12* goes to its ground nuclear state (Be-9 + alpha --->n +
C-12*).  Why is this not a problem, is it a low abundance type
thing, can one calculate a dose rate (resulting from the 4.43
MeV gamma) from a 1Ci PuBe source based on the amount of Be 
present in the source? and does anyone know of a reference 
which shows the gamma spectrum for a PuBe source? (I have
seen plenty of references showing the neutron spectrum).
Thanks!

D. Steva