reprinted from NUCLEONICS |
June 1954, Volume 14, No. 6, Pages 78-84
Copyright 1956, McGraw-Hill Pub. Co., Inc.
330 West 42nd St., New York 36, New York
RaD, RaE, and Po in the Atmosphere
By P. KING,* L. 8. LOCKHART, Jr.,*
R. A. BAUS,* R. L. PATTERSON, Jr.,*
H. FRIEDMAN,{ and I. H. BLIFFORD,
TABLE 1—Rainwater Collections Made at Washington, D. C.*
Pb fraction
Jr.t
Naval Research Laboratory
Washington, D. C.
Date
collected
Volume
collected
G-activily
a-activity
B-activity
a-activity
Jan, 12-30
Mar. 31-Apr. 24
May 3--12
340
220
260
1,400
850
2,140
6
8
10
12,000
14,600
14,200
710
600
490
(1950)
At the time this research was undertaken, a survey of the literature revealed many references concerning the
amounts of the short-lived RaB and
ThB in the atmosphere, but no information on the quantities of the longerlived RaD, Rak, and Po.f{ This
Bi fraction
(gal)
(dpm)
(dpm)
(dpm)
(dpm)
* Activity not corrected for decay, absorption, or backscattering.
dearth of information prompted us to
install facilities at several naval bases
in different parts of the world to collect:
natural radioactive products from the
atmosphere for subsequent analysis at
Washington, D. C.
These collections were made by
either, or sometimes by both, of two
methods. Thefirst method used highcapacity air filter units with filter paper
as the collecting medium. The second
involved the collection of large volumes
of rainwater (100-600 gal) andthe con-
TABLE 2—Distribution of RaE(Bi?!") Activity Among Rainwater Fractions Collected at Washington, D. C.
B-activity (dpm/gal)
Date
collected
(1950)
June 29
centration of the activity with aluminum hydroxide floc, Asa result of the
chemical methods used, the radioactivity from up to 1,000 gallons of rainwater or 108-107ft of air could be con-
July 9
earrier.
July 20
centrated readily on 50-100 mg of
Counting of the separated
July 15-16
G-activity gave a reasonably accurate
measurement of the concentration of
the long-lived products in the atmosphere. Qualitative estimates of the
Po alpha activity were made.
Rain-Water Collection
Volume
Fainfall collected
{in.)
(gal)
Aug. 19
Aug. 23
Sept. 11
1.5
1.4
4.8
(cont.}
1.35
(2-hr
rain)
Rain was collected on 500-1,000-ft?
surfaces made of aluminum sheeting
and was conveyed by aluminum gutters
and pipes to aluminum collecting tanks.
For someof the colleetions made at the
Naval Research Laboratory, automatic
controls diverted portions of the rain
into three different tanks so as to compare the activities collected during
different parts of the rain.
In many of the collections more rain
* High Polymers Branch, Chemistry Div.
+ Electron Opties Branch, Optics Div.
t Recently some information on the
longer-lived activities in air has been reported (7, 2).
Sept. 21
Oct. 8-9
Oct. 23
Nov. 20
0.86
0.54
1.86
0.55
30
60
150
30
60
225
40
55
300
40
60
300
40
60
275
40
60
275
40
115
275
40
60
275
40
60
275
40
60
275
40
60
150
Insoluble
residue f-activity
(qm)
(dpm) *
12.5
2.9
1.4
0.8
0.8
2.4
7.0
2.1
0.9
7.6
1.7
1.7
25.0
3.6
3.0
4.9
1.4
2.0
5.3
3.0
2.0
12.5
2.1
2.1
7.6
3.5
2.5
4.0
6.2
3.0
5.3
13.7
2.8
1,930
1,740
3,200
1,200
160
450
2,360
1,230
3,080
2,300
2,160
3,240
1,700
1,080
2,180
2,760
1,760
10,640
250
790
2,640
1,330
1,740
8,250
1,280
950
2,260
2,000
1,890
3,400
2,220
1,640
1,580
Average
Tank
A
64
40
59
57
43
69
6
33
32
50
56
46
Tank
B
29
3
22
36
18
29
7
29
16
32
27
22
Tank
C
Total
collection
29
21
2
10
11
8
39
10
30
8
12
11
15
6
17
19
13
40
9
30
12
20
22
20
* Activity of BisO; fraction corrected to time of Pb-Bi separation.
C4,