SRG
b, After correlating the results, AFSWP concluded
that the amount of gross activity falling out locally
(within some 24 hours and generally to a distance of
approximately 200 miles) varied by shot, with the
maximum being about 50% of the total activity in the
shot, but the local fallout did not appear to vary
significantly between the reef and barge shots
studied,
No appreciable local fallout resulted from
the airburst.
c, Later, after the series was completed,
effort
was made to analyze available samples to determine
what fractionation occurred;
1.¢., the tendency of
certain isotopes to fall out in more abundance
locally and of others in greater quantity at a distance.
This effort led to APSWP's conclusion that for reef
shots there was substantial fractionation with Strontium
90 falling out at a greater distance, but for barge
shots such fractionation was not evident.
3. At Meeting 1276 on April 9,
1957, the Commission
directed that a major effort be made 1n HARDTACK to establish
more accurately the local fallout with the objective of
determining (also more accurately) the amount deposited world~
wide.
To determine means of accomplishing the Commission's
request, the Division of Military Application assembled a working
group consisting of Graves, Felt, Cowan and Sattisan of LASL,
Ballou, Werner and Fralling of NRDL, Street of UCRL, Graveson of
NYOO,
Isaacs of Scripps,
Lindwarm of CRL,
Shelton, D.
Lay and
LaVier of AFPSWP, Epley and Richie of JTF-7, and Potts, Dunning,
Musick, Schnittke and Watters of AIC,
Dr.
Libby,
Dr. Dunham and
General Starbird participated also.
4, The growp concluded that if we were to make any gain
in knowledge over REDWING in measuring the local fallout:
a. A detailed operation similar to but more
extensive than REDWING, utilizing YAGS-LST~HORIZON-~
land samples but excluding skiffs, would be the best
approach (more extensive use of skiffs would give
little more information);
b. The effort should be directed toward the
taking and the analyzing of samples for a material
balance rather than the establishment of gross
activity contours;