162
DREVINSKY AND PECCI
Table 1—SAMPLING DATA FOR IMPACTOR-FILTER COLLECTIONS
Flight
No.
Sampling
Tropopause
interval, km
km
altitude
—Date
9.1 to 14.4
height,
2576
Mar. 16,1962
2606
Sept. 25,1962
9.1
15.2
21.3
27.4
15.2
21,3
27.4
29.6
10.5
2617
May 16, 1963
9.1 to 15.2
15.2 to 21.3
21.3 to 27.4
12,1
2627
Aug. 15, 1963
8.4
15.2
22,5
27.9
11.8
14,4 to 21.38
21.3 to 27.4
10,7
27.4 to 29.8
to
to
to
to
15.2
22.5
27.9
30.0
Ambient
25.4
20.4
28.2
Radius* of particle
5,T.P.
cutoff size
(stage 1), u
6.20
0.16
1.98
0,954
6,18
0.12
23.4
22,3
23.2
43.1
5.55
2.14
0.793
0.646
0.16
0.18
0.12
0.12
24.4
22.6
32.3
5.72
2.21
1.18
0.16
0.20
0.12
14.6
14.9
19.8
56.4
3.37
1.33
0.700
0.844
0.16
0.20
0.12
0.14
22.7
27.4 to 29.6
to
to
to
to
,
Volume,
31.4
0.351
0.464
0.12
0.12
*The sampler consists of a two-stage impactor with backup filter. The radius of the
particle cutoff size for stage 2 for all flights was 0.02 u, Cutoff sizes are based ona
50% collection efficiency and a particle density of 2 g/cm’ at midaltitude for the sampling interval,
Table 2—IMPACTOR-— FILTER COLLECTION DATES
RELATIVE TO ANNOUNCED NUCLEAR TESTS*
Approximate age
of fresh-debris
Collection
Date of most recent
nuclear test
component (At), days
Mar, 16, 1962
Sept, 25, 1962
May 16, 1963
Nov. 4, 1961t
Within test seriest
Dec. 25, 1962T
132
Fresh
145
date
Aug. 15, 1963
Dec. 25, 1962T
236
*Only announced atmospheric nuclear tests’ with fission.
yields greater than about 1 Mt have been considered.
tConducted by U.S.S.R. at Novaya Zemlya (75°N 55°E).
{The U.S.S.R. conducted about six tests in the megaton
range in September 1962 prior to the collection date. Most
recent test date for the U. S. Pacific tests (2°N 157°W) prior
to the collection date was July 11, 1962.
the test preceding our collection was conducted by the U.S.S.R. Our
collection of September 1962 is expected to contain primarily a mixture of fresh nuclear debris from the U. 8. Operation Dominic Series
and the U.S.8.R. 1962 series. We have assumedthat there is a negligibly
small contribution of radioactivity to our samples from Plowshare
cratering experiments
and surface detonations at the Nevada Test
Site during 1962.
Data for total beta and total gamma activity on the counting date
and for individual radionuclide concentrations on the flight date for
1962 and 1963 collections are presented in Tables 3 and 4, respectively.