Table 5—- RADIONUCLIDE RATIO DATA FOR 1962 IMPACTOR- FILTER
COLLECTIONS
Samplingaltitude
interval
Fraction
‘44Cce/%sr
MIR,sr
140B a/M4Ce
Mar. 16, 1962
9.1~14.4
Stage 1
Stage 2
Filter
6.74 + 3.32
25.7 + 1.4
25.3 + 4.8
<0.2
0.100 + 0.023
<1.7
< 0.03
0.00389 + 0.00088
< 0.07
14,4=— 21.3
Stage 1
Stage 2
Filter
1.40 + 0.65
37.3 + 4.2 40.4+1.8
< 0.3
0.650 + 0.083
<0.78
<0.2
0.017 + 0.001
<0.019 ©
21.3~— 27.4
Stage 1
3.1 + 1.0
0.30 + 0.19
<1]
0.021 + 0.011
<0.5
27.4~— 29.8
Stage 1
> 0.6
Filter
4.2421
Stage 2
Filter
Stage 2
14.1 + 4.5
1.87 + 0.36
.
>8
Sept. 25, 1962
9.1—-15.2
Stage 1
54 + 34
Filter
19 +9
Stage 2
28.0 + 3.0
45,.2— 21.3
Stage 1
> 40
21.3—27.4
Stage 1
Stage 2
> 20
6.24 + 2.35
Stage 1
4.2 + 3.4
Filter
> 5.2
Stage 2
Filter
Filter
27.4— 29.6
Stage 2
31.0 + 7.7
39.4 + 6.9
12+7
>9
If one of the primary causes of chemical fractionation is the presence
of gaseous precursors in fission-product decay chains, one might have
expected fractionation between ‘4Ce and Sr. The mass-144 chain has
no known gaseous precursors except for the extremely short-lived
xenon, whereas the mass-90 chain includes 1.4-sec-bromine and 33sec-krypton precursors. It appears, therefore, that the particle size
distribution of “‘Ce and “Sr in debris of this age is independent of
considerations of the gaseous nature of precursors.
ACTIVITY RATIOS
For the comparison of the size distributions of individual radionuclides within each given flight and over all flights, it is best to con-
Sider activity ratios. Direct insight concerning the possibility of
chemical fractionation between specific radionuclides can be obtained.
Tables 5 and 6 contain all activity-ratio data, corrected for radioactive
decay to the flight date, obtained for the 1962 and 1963 impactor —filter