he Period 2100, April 1h, 1955 to 1630, April 20, 1955
CL 562-P
CL 563-P
Open tub
Coveredtub-
5305 + 3.3 dom total
1
3h +1,8 "
5S. Period 1800, April 28, 1955 to 0930, May 13, 1955
CL 617-P
CL 618-P
CL 619-P
Open tub
Covered tub
Wet" tub
67 + 7 dpm total
83*9 "
Mm
72.8 + 4.9 dpm total
6. Period 1100, May 13, 1955 to 1130, May 23, 1955
CL 627-P
CL 628-P
Open tub
Covered tub
90 + 5 dpm total
70 + 5
tt
"
7. Period 1700, May 23, 1955 to 1030, June 6, 1955
CL 64,8
CL 645.
CL 646
Open tub
Covered tub
Met" tub
210 + 8 dpm total
239 ¥ 12"
4
221*68 "
The agreement in total Sr90 activity collected by each of the several
methods is gratifying.
The only significant discrepancy is the low value for
CL 563-P which might be explained by the occurrence of a very heavy rainfall
with a possible resultant loss of sample due to splashing off the plastic
cover,
Another possibility is the occurrence of dry fallout which could have
been blown off the plastic cover by surface winds.
It appears that the Sr70
is water soluble at the time of collection and is not absorbed on the walls of
the vessels,
It is further indicated that once deposited in rains, the Sr70
fallout does not blow around significantly.
These results testify to the adequacy of the water collection and chemical
separation procedures used and indicate that an open tub provides for reliable
collection of precipitation for extended periods of time.
Since the Sr acti-
vity is apparently quite soluble, large volume collections can be safely
aliquotted to reduce the sample shipment problem.
Thus, the collection of
precipitation appears to be a practicable method to auguent, or even replace,
the sticky paper collector as a general method of world wide monitoring.