Simulated sources containing sup252Cf equivalents of 0.1 to 1.0 milligrams were prepared. Samarium was used as the simulant in a modified chemical plating technique similar to that used to prepare palladium-californium oxide cermet for industrial applications. The length of the platinum-10 percent iridium doubly encapsulated source with its protective sheath is 0.545 in. (14.1 mm). Outside dia of the source, including its sheath, is 0.109 in. (2.8 mm). Existing ''Brachytrons'' can accommodate this source form. This capsule system will withstand internal gas pressures from helium due to alpha decay and fission gases from a 1 mg sup252Cf source after ten years if the source is subjected to a maximum temperature of 800sup0C, the theoretical temperature of an accidental fire. Under these conditions the safety factor is 3. The capsule system is being tested with tracer amounts of sup252Cf to ensure that it will withstand adverse service conditions as well as tests specified for Special Form Materials. (auth