2
out occurs with snow, the gummed-film
method may grossly underestimate the
true fallout values. Despite this objec-
Table 1. Strontium-90 deposition and cumulative gamma dose as estimated by gummed-film measurements through June 1957,
:
Ex-
Sr”
Station
ternal
(mc/mi*)
dose
Australia
Sydney
Bermuda
Bolivia
La Paz
Canada
Churchill, Manitoba
9
18
6
17
2i:
9
48
22
6
11
13
:
25
New Zealand
Wellington
Montreal, Québec
Moosoonee, Ontario
North Bay, Ontario
16
13
17
Regina, Saskatchewan
13
Ottawa, Ontario
Seven Islands, Quebec
Stephenville, Newfoundland
Winnepeg, Manitoba
Ceylon
Colombo
Costa Rica
San Jose
Ecuador
Quito
Ethiopia
Addis Ababa
French West Africa
Dakar
Germany
:
Rhein Main
Greenland
Thule
Hawaii
.
French Frigate Shoals
Lihue
Hilo
Honolulu
33
29
34
12
25
27
12
27
20
42
23
9
7
45
.
29
17
Nigeria
Lagos
Norway
Oslo
Pacific Ocean
39
“48
30
Chicago, I).
22
50
Corpus Christi, Tex.
Dallas, Tex.
.
Des Moines, Iowa
12
25
27-
25
60
63
5
10
8
14
7
3
23.
17
52
.
78
;
30
14
65
44
12
_ 22
15
27
9
15
Panama Canal Zone
Puerto Rico
21
18
30
42
38
59
Saudi Arabia
Dhahran
Scotland
Islands
MidwayIsland
Noumea, New
Caledonia
36
17
19
-20
9.
22
San Juan
15
29
15
28
18
30
14
25
il
Detroit, Mich.
65
26
30
45
23
160
66
it
24
13
24
20
54
23
75
Minneapolis, Minn.
25
New Haven, Conn. —s-20
51
43
-
16
New Orleans, La.
New York, N.Y.
Philadelphia, Pa.
-Pittsburgh, Pa,
Rapid City, §.D.
Rochester, N.Y.
:
29
13
18
Las Vegas, Nev.
Miami, Fla.
45
41
58
25 ©
44
69
“49
39 -
Los Angeles, Calif,
Louisville, Ky.
Medford, Oreg.
Memphis, Tenn.
150
22
Grand Junction, Colo.
Jacksonville, Fla.
Knoxville, Tenn.
48
36 -
8...
20
26
13
27.
20
_ Cleveland, Ohio
Concord, N.H.
170
22
45
Cape Hatteras, N.C.
87
WakeIsland
Prestwick
Continental United States
Albuquerque, N.M.
-160
Johnston Island
Koror, Palau Island
Manila, Philippine
19
16
140
23
21
8
10
23
41
7
i
Pretoria
41
7
33
14
34
39
41
Truk, Caroline Islands
Ponape, Caroline
Islands
:
Canton Island
5
16
23
39
Atlanta, Ga,
Billings, Mont.
Binghamton, N.Y.
Boise, Idaho
Boston, Mass.
,
Iwo Jima
¥ dose
(mrad) *
19
-
-
{imc/mi*)
10
Yap, Caroline Islands
Guan, Caroline
Islands
Station
Ex-
ternal
* 43
:
.
Sr”
23
.
Sidi Slimane
:
Thailand
Bangkok
10
Tripoli
Libya
24
Union of South Africa
.
~ Durban
o
(36
36
20
21
-
Monrovia
Malaya
‘Singapore
;
Mexico
Mexico City
Moncton, New Brunswick
.
29
19
Liberia
Morocco
yy dose
(mrad)*
21.
.
13
.
Tokyo
33
Goose Bay, Labrador ‘ 13
:
Misawa
Nagasaki
18
ternal
(mc/mi*)
Iceland
Keflavik
Italy
Milan
Japan |
Hiroshima
Edmonton, Alberta
Ex-
Sr”
Station
(mrad) *
Outside continental United States
Alaska
:
Anchorage
12 20
Fairbanks
15
26
Juneau.
16
30 Nome
9
17
Argentina
” Buenos Aires
:
~
=
Salt Lake City, Utah
San Francisco, Calif.
28
28
19
26
18
19
Seattle, Wash.
Tucson, Ariz.
Washington, D.C.
Wichita, Kan.
37
64
- 54
39
46
45
37°
54
180. .
14- . 23
Scottsbluff, Neb.
38
+
19
25
18
25
prey tg
of moderate rainfall in a temperate climate, yields fallout samples with an overall efficiency of about 63 percent compared with the values from high-walled
pots. In regions where much of the fall-
1 Ir
In earlier reports, it has been shown’
that the gummed film, under conditions
tion, the gummed-film technique has
proved to be desirable because of the
simplicity with which daily samples can
be accumulated from a large number of
widely scattered locations.
Since late 1954, the computation of
strontium-90 from the total beta activity
of the gummed-film samples has become
increasingly difficult because the computed values are sensitive to the assumed
age of the debris. The accumulation of
long-lived fission products in the stratosphere and the greater frequency of
weapon tests has greatly complicated the
problem of assigning an age to the
ferme
which strontium-90 and other isotopes
may be determined directly by radiochemical analyses. Gamma emitters may
be evaluated by spectroscopy.
The principal advantage of the
gummed-film method, in addition to its
simplicity, is that it permits daily sampling. This is important for the estimation of gammadose.
There can be no absolute sampling
procedure for fallout deposition because
the deposition in a given situation will
be influenced by the type of surface.
However, to permit some basis of comparison, the collection performance of
the gummed film has been studied in
relation to the collection performance of
pots.
73
34
49
35
62
* The tabulated values are calculated infinity exterial gamma dose in millirad. The probable exposure to the population. allowing for shielding and weathering, &
ert
nels, permit collection of individual rain-
falls or weekly or monthly deposits, from