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Delayed Shutters
These shutters were closed et zero time but subsequently were opened
for a pre-selected time interval during the power pulse.
sustained burns in this series,
Four of 16 rabbits
The interval of 10 to 250 msec produced a
lesion in 1 of 2 animals exposed.
In 2 of 2 rabbits the increment of 10 to
1000 msec produced burns essentially the seme size and severity as those
observed in the ERT study.
The interval of 500 to 600 msec caused a small
mild burn in 1 of 2 animals.
Although this animal was exposed only about
one-third of his blink reflex time, the dose rate was near the maxirum for
this shot.
The time of the meximum is calculated at about 600 + 20 msec.
No burns were produced efter the first second of the flash,
Protective Flectronic Shutters
No burns were sustained by the 2 rabbits exposed behind these shutters.
Unfortunately the electronic recordinrs system for these devices was inoper-
ative at the time of the shot.
The results of this portion of the study ere
inconclusive.
Protective Filters
Only 2 burns were produced in 27 exposures behind the fixed density
optical filters.
moderate severity.
These lesions were both 1/Z d.d. in size end were of
Unexplainatly, neither burn was produced behind the
least protective filters.
CONCLUSIONS
The tlink reflex time for man and animals is not fastyenough to protect
against the flash from an atomic detonation
An air burst of this size on a clear day (90 percent transmission/rile) is
sufficient to cause large chorioretinal burns in rabbits and monkeys at
7.€ statute miles and in men at 5.1 statute miles.
Additional date are
needed in order to estellish the limiting distance for burns\
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