HVL

[Les Slaback <lester.slaback@nist.gov>]

By examination (i.e., w/o doing the calculations) this would appear to be a
good example of a nuclide where the HVL model is a dismal failure.  Given
the wide range of abundant gammas (from 113 to 418 keV) none will be
dominant even after a factor of 20 attenuation so that the 'effective'
attenuation coefficient will be continually changing.  Hence there is no
characteristic HVL.
As espoused previously on RADSAFE due the specific shielding calculation.

>I need to know the Half value layer (in lead) of Lu-177.  I used the equation 
>for the mean attenuation coefficient on page 165 of the Rad health Handbook 
>(Revised edition) and determined the thickness of lead for 95% attenuation
to be 
>2.74 mm.  I am skeptical of this approach and/or my use of it.
>Wade Sewell

Disclaimer:  the above are the personal musings of the author, and do not
represent any past, present, or future position of NIST, the U.S. government,
or anyone else who might think that they are in a position of authority. 
Lester Slaback, Jr.  [Lester.Slaback@NIST.GOV] 
NBSR Health Physics 
Center for Neutron Research 
NIST
100 Bureau Dr.  STOP 3543 
Gaithersburg, MD  20899-3543 
301 975-5810 
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