RADIOCHEMICAL FRACTIONATION
CHARACTERISTICS OF SINGLE PARTICLES
FROM HIGH-YIELD AIR BURSTS
P. BENSON, C. E. GLEIT, and L. LEVENTHAL
Tracerlab, A Division of Laboratory for Electronics, Inc.,
Richmond, California
ABSTRACT
The radiochemical fractionation characteristics from two Operation
Dominic high-yield air bursts were studied. Particles measuring from
2.9 to 20.0 u were isolated from filter-paper matrices by autoradiographic registration and confirmed by optical microscopy. After physical measurements radiochemical and/or gamma-spectroscopy studies
were performed on individual and aggregates of particles. Of particular
interest was the distribution of volatile and refractory nuclides for each
particle size. The nuclides radiochemically analyzed were *°Mo, 8Sr,
Sr Zp 128m 132P7— 1icg MB,Mice Moe Ming %37y, and 239Np,
Gamma-spectra analysis was used to determine the Zr andBa con-
centrations in 334 particles, A computer technique for resolving these
nuclides and Mo, !Ru, 41,Te, "cs, Mice, M4ce, ’Nd, and9Np
was developed.
The particles were found to be extremely fractionated. A logarith-
mic fractionation correlation plot for °Ba was determined which com-
pared within the limits of error with data plotted by Freiling for high-
yield water bursts. The logarithms of ™Zr and '°Baactivities were
plotted as functions of the particle diameters for the two shots. The
slopes for the regression plot for Zr were 3.41 + 0.18 and 3.09 + 0.37.
These values imply a cubic relation. The slopes for the regression plot
for “°Ba were 2.63 + 0.24 and 2.32 + 0.50, somewhat between a square
and a cubic relation. These results point toward condensation of the re-
fractory nuclides initially with subsequent precipitation of the volatiles
on the particles at later times.
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