sort RARE pe Tes 3 ' eT mmy oad 4 pees aT Tee 5.3 VASTATICN OF RADTOCHEMICAL SOMPOSITICN WITH PARTICLE SIZE, ZERO FOUNT PNUTPONMENT, AND TIME AND DISTANGE CF COLLECTION The variation of radiochemical composition with narticle size 4s illustrated graphically in Fig. 5.1 = 5.7. The activity concentration decreases regularly with particle size to about 50 up; above 50 p the Situation 4s sonexhat obscure. Figs. 5.1, 5.3, and 5.4 exhibit a sharp discontinuity at 50 p. It 1s possible to draw lines throurch the points in the other figures in such a manner as to indicate dis- continuities, rather than the smooth curves shown. It has bgen postulated20/ that this discontinuity is related to the breaking up of agglomerates by the Poller analyzer, as discussed in the preceding section. The differences between the various curves detail the fractiona- tion indicated by the R-values (Tables 4.3). Only the relationships betwaen the different curves can be regarded as significsnt, howeven because of the uncertainty in the ver cent active particles mentioned in the preceding scetion. In another reporiZi/ the authors rave used certain assumptions regarding Ca45 to obtain per cent active verticles figures. Correction of the data by these figures leads to curves whose slopes have been interoreted to give an insight into the mechenism of particle formation. mc/mg dhdaasnattaiaciin Oi i \ 2 5 0 20 50 DIAMETER IN MICRONS Fig. 5.1 100 $00 Activity Concentration of Sr®9 vs Particle Size 40 SECRET-— RESTRICTED DATA sai 200