3
,
NAVAL BESEARCH LABORATORY
TABLE i
Comparison of Collection of Radioactivity by
Gummed Paper and Filtration Techniques
ft
Date of
.
.
Filter
Collection (d/m/tt’)
i
2/21 - 2/28)
2/28
3/7
3/14
3/21
13/28
4/4
4/11
4/18
4/25
5/2
5/9
5/16
5/23
- 3/7
- 3/14;
- 3/21}
- 3/28]
- 4/4
-4/11]
- 4/18;
- 4/25}
- 5/2
- 5/9
-5/16|
- 5/23
- 5/31
Paper
Fallout
(a/m/ft? /day)| (ft/day)
,
28 x 10%
8.3
18
19
24 |
22
27 ©
47
30
49
;
29
13
730
290
.
24
46
19,000
‘330
18
50
31
210
200
-
100
4,400
. 790
1,400
1,600
Average
Cc
.
Dec. 1954
Jan. 1955
Feb. (before tests)
(after tests)
1.78
0.13
1.13
0. 43
0
0.07
1.50
0.47
5.5
88
25
6.7
8.0
0. 40
0. 01
1. 62
0. 50
1.11
a
;
43x 10°
No. of
Tests
0
0
0 ;
:
Rains
Rate o Fallout
(ft/day)
wo Rain
Rain
8
{1.0 X10°}
1.4 x10°
7
0.7
1.2
1.1
3.7
9 .
9.2
1
12
2.4
50
April
3
15
3.9
133
May
3
1:18.
March
2.
:
No. of
5.2,
0.7..
12
7
2.7.*10°|
30 x10°
From the available data, it appears that, on the average, and particularly in the
absence of well-defined clouds of fission products, the concept of a rate of fallout may be
useful in correlating the concentration of activity in the air with the deposition. Obviously,
large variations may be encountered in certain instances: i.e., for short distances from
the detonation or for short times after a test. The present work indicates the need for
more extensive measurements.
:
-.
424. G05”
ty
fa
“J.
1.22
“|
1
Average
s
1.8 10°
3.5
0.7
38
12
1.1
1.7
400
11
ks
’
(in. . )
TABLE 2
. Effect of Rain on Apparent Rates of Fallout
Month
*
Rain
Rate of
Gummed