Appendix C PARTICLE DATA AND CHARACTERISTICS, SHOT KOA . C.1 SIZE DISTRIBUTION, FALL RATE, AND SPECIFIC ACTIVITY DATA Fall rate distribution data, particle size data, and specific-activity fall-rate data are presented in graphical form in Figures C.1 through C.13, for the cloud and fallout samples listed in Table C.1. Samples, 500, 502, and 977 from the cloud were separated into coarse and fine fractions with the Bahco centrifuge before determination of the distribution curves. The boundary between the centrifuge fractions is as given in Appendix B. No fal] rate work was done on samples taken from the cloud at times later than 4 hours because of the small quantity of material collected. These resuits are being reported primarily for record purposes. C.2 PARTICLE CHARACTERISTICS Most of the particles were translucent white and had an irregular shape. Some flaky aggregates—small spheres apparently formed by condensation——and clusters of varying sizes were also present. Many of the larger particles were discolored with a reddish- brown stain, presumably due to iron oxide. The main constituents were identified as Ca(OH), and CaCOy (both calcite and aragonite) by examination with polarized light and by X-ray diffraction. Small quantities of ocean water salts were observed in all the samples. The particles disintegrated spontaneously into many small fragments when brought into contact with liquids. The disintegration was most rapid with water but also occurred at a slower rate with hydrocarbons and other fluids. Because of this effect, their density could not be determined by the bromobenzene-bromoform method. Size measurement and type classification were described in Section 2.4; this investiga- tion is summarized in Table C.2.