thorium lenses

["Wenzel, CPT Krista K." <WENZEL@eglin.af.mil>]

Does anyone know of studies done to quantify airborne respirable thorium
when cleaning up a broken thoriated lens?   I'm trying to do a potential
dose calculation for workers who clean up a lens coated with thorium
fluoride.  I've got all the numbers except what I would expect
(guesstimate) for airborne respirable thorium during clean up.   I know
it's very low, but I need to quantify somehow.

Texas Instruments has recommended wearing respirators for ALARA.  This
is not really feasible as lenses rarely break and it would mean
fit-testing dozens of people.  (I plan to air sample when the next lens
breaks.)

Krista K. Wenzel, Capt, USAF, BSC
wenzel@eglin.af.mil