130
LOCKHART, PATTERSON, AND SAUNDERS
S
|
GROSS BETA ACTIVITY, PC/M?
13
DEC.
NOV.
L
JAN.
| wml.
FEB.
MAR,
1962
APR.
len
MAY
|
JUNE
1963
Fig. 5-——Concentration of fission-product beta activity in the ground-
level air at Washington, D. C., during 1963.