They are formed by rapid heating of solid precursor material and subsequent melting, followed by slow cooling.

Inexpensive precursor materials are used and reacted according to the reaction below:

Each precursor material is examined using the same method.

These precursor materials can then be placed in stainless steel containers that have been leak tested before being converted into radioactive sources.

These precursor materials can then be placed within stainless steel containers, which are leak tested before being converted into radioactive sources.

Large sections of the precursor material were produced as castings, moldings or machined into a predetermined shape.

However, the environmental setting, the energy source for the heating, and the precursor material are not known.

Sol-gel processing allows for homogeneous mixing of precursor materials at the atomic level.

The precursor material is gas, liquid or solid.

The shelf life can be shortened by impurities in precursor materials.