BOMBS AT BIKINI 



This energy was transmitted initially as thermal 

 radiation, gamma radiation, neutron radiation, other 

 nuclear radiations, and shock wave. 



The thermal radiation was extremely intense dur- 

 ing the first small fraction of a second; photographs 

 taken from the air show the water brightly illuminated 

 from beneath the surface. The region in which the light 

 originated, called the underwater fireball or "gas 

 bubble," rose rapidly to the surface and, still within 

 the first small fraction of a second, burst through the 

 surface to spearhead the upward shoot of the water 

 column. Many observers failed to see any light at all, 

 but the photographs taken with the Eastman high- 

 speed cameras and the Fastax cameras show clearly 

 the presence of a brilliant area atop the column during 

 the first instant of its rise. The practical effect of the 

 thermal radiation was, of course, almost nil. 



The neutron radiation was of little immediate con- 

 sequence. Nearly all of it was absorbed in the sea 

 water; almost none reached even the nearest target 

 vessels. A significant fraction of the neutrons was ab- 

 sorbed by the sodium in the water, thereby producing 

 radioactive sodium (Na^''). Neutrons were heavily ab- 

 sorbed also by hydrogen, chlorine, and other elements 

 found in sea water. 



drawn definitions, were agreed on. Among these terms were the 

 following: dome, fillet, side jets, hright tracks, cauliflower cloud, 

 fallout, air shock disk, water shock disk, base surge, water mound, 

 uprush, after cloud. These terms are defined in later pages of this 

 chapter. 



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