Re: Samarium-153 -Reply

["Dale E. Boyce" <dale@radpro.uchicago.edu>]

A question about dose rate constants came up in our group recently.
The Health Physics and Radiological Health Handbook lists the
dose constant for I-125 as 7.432E-5 mSv/h/MBq at 1 meter.  That
is about 275 mRem/h/Ci at 1 meter.   Amersham safety data sheets
list it at 41 uSv/h/MBq or 152 mRem/h/Ci.  An unreferenced table
apparently from the UCLA Office of Environmental Health and Safety
dated 1971 lists it as 70 mR/h/Ci at 1 meter.  That one I know
is effected by the difference between R and Rem at that energy.
A program that I wrote to calculate the dose from photon energies
branching ratios and mass energy absorbtion coefficients comes
up with about 140 mRem.

Does anyone have an opinion on what the real value is (i.e. with
an error bar somewhat less than a factor of two)?  Is there this much
scatter in reported values for other low energy emitters?