500
GUSTAFSON, BRAR, AND MUNIAK
maximum concentration during June and July 1961, and the *4Mn spring
maximums have coincided in time with those of '"'Cs during 1962
through 1964. The '"cs/!"Rh activity ratio for Orange debris is not
known, although a production figure of 3 Mc of '“Rh has been reported
by Kalkstein.® Cesium-137 from other shots at high altitude may have
become mixed with that from Orange. Aircraft sampling at 50,000 ft
during May 1961 indicated a ‘"’cs/!"Rh ratio of nearly unity.® This
value would imply that nearly all the '*’Cs seen during the spring of
1961 was of high-altitude origin.
Likewise, it is difficult to determine the actual amountof '*’cs
produced along with the ‘4yIn. The highest concentrations of ‘4utn ob-
served in the Ash Can balloon flights were collected’ during the spring
of 1962 and indicated *‘Mn/!*"Cs ratios of 30 to 1 to 40 to 1. Sampling
conducted at 60,000 to 65,000 ft indicated *“Mn/'"cs ratios closer to
10 to 1 during most of 1962 with a decrease to approximately 5 to 1 in
1963 and 1964 as shown in Fig. 2. The “Mn/!*"Cs ratio observed in
surface air at Argonne during this time is also indicated in Fig. 2.
TTT TTT TTT TT TOT TTT TT TT TT ed
A
A
_
|
a
SURFACE AIR, ARGONNE, ILL.
— —— 60,000 TO 65,000 FT, SAN ANGELO, TEX.
L
107!
4
_.
_
Lite tL prep ppt ep etttt te ttt
Jan.— Dec.
1962
Jan.— Dec.
1963
Jan.— Dec.
1964
Fig. 2—4*Mn/''Cs activity ratio in surface air at Argonne, Ill., and at
60,000 to 65,000ft at San Angelo, Tex.