Copmennn.
H + 1 hr ccontour to be roughly two times that predicted by existing

scaling methods and the area within the 100 r/hr contour to be less than

one third that predicted.

The fallout pattern extended a shorter distance downwind than
bad been predicted by current scaling methods in spite of the fact that

the cloud rose to a greater height than these methods predicted.
Integration of the intensity areas from dose-rate contours accounted for 85% of
the activity.

BH
An analysis of time of arrival of activity data, radiochemistry, photography, and other available data indicates that the base

surge was the primary carrier of activity in the upwind and crosswind

direction.

Time of arrival data were obtained at seven locations from

300 to 4,5CO yd from ground zero indicating fallout to have traveled down-

wind at the rate of less than 2 mph (ground speed), although the surface
wind was 12 mph.

At D +8 days about 90% of the activity (6,000 to 12,000 mr/hr)

on the crater lip was contained in the top 12 inches of soil.
This
distributicn was also present 3 mo after the shot when an appreciable
amount of activity (200 to 500 mr/hr)*still remained in the lip, while in

the crater 804 to 90% of the activity was covered by caverins and landslides to a depth of at least 3 ft.

The radiation intensity of the crater

lip at approximately 6 mo after the shot was 100 to 200 mr/hr.

(u)
Gamma-intensity measurements made in the fallout area showed
that the dose rate from H + 2 hr to D + 4 days followed T-1-2 decay.
A
beta-decay curve was obtained which is similar to those found at other
tests.
ta were obtained which will furnish information concerning the
effect of scaled depth upon such properties as specific activity, activity
particle size distribution, and total activity associated with fallout.

(u)

On aerial surveys, the rate at which intensity decreases with

altitude is dependent on the position within the fallout pattern, i.e.,

air-ground correlation factors (intensity at 500 ft/intensity on ground)

were found to vary from 0.12 to 0.45 for an altitude of 500 ft.
(u)

Tre preliminary report of this work appears as ITR~1119.

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