AEROSOLS CONTAINING RADIOACTIVE PARTICLES 



Fig. 1. Particles from an aerosol containing Sr*'S04 . 

 1. Particles transferred from membrane filter to a "Formvar" -coated screen. 80OOX. The 

 broad gray band in the lower left corner is a common contaminant in this type of preparation. 

 2, 3 and 4. Selected fields illustrating particles collected directlj^ on "Formvar"-coated 

 screens. 25,000X. 



from which the particles were transferred, or 

 they may be small particles of Pluronics, a 

 dispersing agent present in the aerosol gener- 

 ation suspension. The individual needles are 

 rarely longer than 1 micron, or wider than 

 0.05 micron. 



Ruthenium Dioxide. Particles obtained 

 from aerosols containing Ru^''^02 are illus- 

 trated in Fig. 2. The particles are character- 

 istically three-dimensional chain aggregates, 

 each aggregate consisting of many roughly 

 spheroid unit particles. Ruthenium dioxide 



73 



