Sams Brilliant Research Career in Science

Sam became a graduate student in chemistry in January 1936. His research director was Professor Willard Libby, who later won the Nobel Prize in Chemistry for the discovery and development of carbon-14 in dating old objects. Sam carried out his work with beams generated by the cyclotrons, with neutrons, and with artificial radioactive substances made by these beams. 

Helena, George, Connie, and Dana. Fall 1943 Photographs 3.4. Supplied by Dr. George Ruben. 

In May 1938, Sam received the degree of Doctor of Philosophy in Chemistry. The title of his doctoral dissertation is Studies in Artificial Radioactivity. It has three sections (i) One involves fimdamental physics of iodine and neutrons, (ii) The second section concerned chemical reaction rates using radioactive iron, (iii) The third and longest section used radioactive tracers to study a fundamental problem in biology. It involved stomach-feeding radioactive phosphorus to rats, and after an elapsed period of time he killed the rats to determine which organs of the body had taken up the radioactivity. Ruben published six articles from his thesis research. 

The radioactive carbon used in these studies was carbon-11, abbreviated as which was prepared by bombarding boric oxide in the 70 centimeter cyclotron. Carbon-11 has a half life of twenty minutes, which means that one half of it remains after twenty minutes, one quarter remains after forty minutes, one eighth remains after one hour, one part in sixty four remains after two hours. An experiment using carbon-11 needs to be completed within a small number of hours. A book by Martin D. Kamen Radiant Science, Dark Politics, A Memoir of the Nuclear A e, University of California Press, Berkeley and Los Angeles, California, 1985] gives this account of working in the laboratory with the fast decaying carbon-11. 

Sam and his team developed a new experimental method to trace the course of carbon in photosynthesis, and from the first they made 

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