re EEE EEE 3.2.2 Accuracy of Radiochemistry. 0018933 Radionuclide analyses on the particle samples were accurate to 5 percent on a relative basis and the gas counting had an accuracy better than 10 percent. 3.2.3 Reliability of Sampling. Certain points on the curves of Figure 3-1 > are to be attributed somewhat less significance than the others due to uncertainties regarding the samples. On Koa the fission ratio for sample 981 R may be off by a factor of 2 due to the small sample size and high counter background from fallout which would decrease the counting accuracy. On Walnut sample 978 L (27.5 hr.) the probe velocity was low and Kr®? only was determined. Sample 980 L for Oak has been disregarded due to the very low probe velocity which would tend to make the Ho7? to Kr®8 ratio too high. 3.2.4 Particle Fall Rates and Specific Activities. The particle size dis- tributions (and hence the specific activity as a function of particle size) could be altered in a number of ways before the fall rate studies were made. Among these are breakup of particles by impaction on the filter, loss of fine particles in handling, spontaneous breakup of particles in the fallout process itself due to atmospheric moisture (cf. Appendix C re the behavior of particles in liquids), and several other possible means of alteration. One can calculate what fall rate a particle would need to fall 59,000 feet in 4, hours, i.e., to be collected in Koa Massive Ll. This fall rate is 125 cm/SeC. The diameter of a spherical particle with a fall rate of 125 cm/sec. is about 120 microns. 2s 125 cm/sec. Figure Cl gives essentially no particles with fall rates as great However, Figure C 10 gives about 30 per cent of the particles with diameters greater than 120 microns. This disagreement is possibly due to the effect of the micromerograph on weakly constructed particles, and the effect may not te uniform on all types of particles.