SCIENTIFIC OFFENSIVE 



course, is the blanket name given to the fragments 

 formed when atoms of uranium or phitonium are 

 split. The splitting, which occurs within a small frac- 

 tion of a second after the atom captures a neutron, 

 does not always give the same kinds of fragments. In 

 fact, more than 100 kinds have been identified.* Among 

 them are : nuclei of atoms of bromine, krypton, rubi- 

 dium, strontium, ytterbium, columbium, molybdenum, 

 antimony, telurium, iodine, xenon, cesium, barium, 

 lanthanum. As the bomb detonates, hilUo7is of hilUons 

 of such fragments are flung out. 



To radiologists, the importance of these fission 

 products lies in their instability. The products are not 

 well-adjusted at the time of their birth, but go through 

 tumid tuous "nervous breakdowns"; their electrical 

 charge is poorly matched to their weight. Readjust- 

 ment usually takes the form of emitting gamma rays, 

 electrons, or neutrons. 



The principal questions asked by radiologists were : 

 How rapidly do these readjustments come? How soon 

 are they finished? Which type of radiation predomi- 

 nates ? Of course, for any one kind of fission product 

 the answers may usually be obtainable in the labora- 

 tory; but the fission products are such a motley mix- 

 ture, such an ephemeral hodge-podge, that their cumu- 



*A recent tabulation, presented in the Jouryial of the American 

 Chemical Society for Novemher 1946, lists 160 fission products 

 (including isotopes). 



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