  Flash radiography of large hydrodynamic experiments driven by high explosives
is a diagnostic method in use at many laboratories. A major contributor to the
practical resolution obtained by this point-projection technique is the size of
the source spot. A variety of techniques for measuring spot size are in use at
the different laboratories, as are different definitions of spot size.
Additional metrics in common use at Los Alamos National Laboratory are
considered here, and compared with those previously discussed in J. Opt. Soc.
