Glenn Seaborg and John Livingood—Activated Sample Preparations (1936-1938)
These items were donated by Glenn Seaborg and identified by him as activated samples that he and John (Jack) Livingood had produced at the University of California in Berkeley. This would have been in 1936 to 1938—one of the small boxes in which these came has "Oct 9 '37" indicated in Livingood's handwriting. Livingood activated samples in a cyclotron and Seaborg separated out the elements of interest. He then placed these preparations on cardboard and covered them with cellophane. Livingood then analyzed the properties of the induced radioactivity with an electroscope.
The writing on the cardboard holders (photo to right) is as follows:
Top row, left to right
- Sample 1: "Co of Ni + n XII"
- Sample 2: "Co of Mn + He V"
- Sample 3: "Co [of ?] Ni + D I"
Bottom row, left to right.
- Sample 1: "[Sn of ?] Sn + D III"
- Sample 2: "Co of Mn + He VI"
- Sample 3. "Zn of Zn + D I"
Each sample holder is 1 1/4" wide (not counting the small tab) and 2 1/2" long.
Let me use an example to explain what the information on the cards indicates. In one important experiment, Livingood bombarded an iron target with deuterons. This would be symbolized Fe + D. Seaborg then dissolved the target and chemically separated out three elements: iron (Fe), cobalt (Co), and manganese (Mn). These three preparations would be indicated as Fe of Fe + D, Co of Fe + D, and Mn of Fe + D respectively. While I am not sure what the roman numeral at the end indicates, I suspect that it refers to a particular experimental run.
Using this method, Seaborg and Livingood discovered and characterized a number of radioisotopes including I-131, Fe-55, Fe-59, Zn-65 and Co-60. I like to imagine, and it is possible, that some of these cards are associated with the discovery of Co-60.
Livingood would later say, "It was a wonderful time. Radioactive elements fell in our laps as though we were shaking apples off a tree."
To give a better idea of what was involved in these investigations, I will quote parts of a presentation made by Seaborg at the 1970 annual meeting of the Society of Nuclear Medicine:
"I became involved in the discovery of a number of radioisotopes that in subsequent years have found substantial applicants in the diagnosis and treatment of disease. These include iodine-131, cobalt-60, technetium-99m, iron-59, iron-55, cobalt-57, cesium-137, and zinc-65. of the 8,000,000 administrations per year of radioisotopes in the United States, some 90% utilize either iodine-131, cobalt-60 or technetium-99m."
"My collaborator in most of this work was a young nuclear physicist, John J. Livingood. Our association extended over a period of about five years (1936-1941) even though he left Berkeley to accept a position at Harvard University near the end of 1938. the transmutation reactions which led to the production of these radioisotopes were effected first with the 27-inch cyclotron, which later became the 37-inch cyclotron, in the old Radiation Laboratory, and finally with the 60-inch cyclotron in the Crocker Laboratory."
"The chemical work I performed during my continuing collaboration with Jack while he was still in Berkeley was all done in this little corner of the room in LeConte Hall. Our teamwork in every instance consisted of Jack's performing the cyclotron bombardments, after which I dissolved the target material and made the chemical separations. We next mounted the chemical end products on cardboard sheets and covered these with thin cellophane. He then measured their radiation characteristics [half-life, energy and type of emitted radiation], using a small Lauritsen quartz fiber electroscope mounted in a sort of cubbyhole room in the basement at the opposite end of LeConte Hall."
Seaborg dissolved the activated target in acid and separated out three elements - usually a rush job. First he precipitated out the target element (e.g., nickel) using a "carrier." The precipitate was collected on a filter and transferred to the cardboard card. He then used the appropriate carriers to precipitate two more elements: the element whose atomic number was one greater than the target (e.g., copper) and the element whose atomic number was one less than that of the target (e.g., cobalt). Seaborg commented "Easy for a chemist, but for most physicists [like Jack], an unfamiliar world].
"Our motivation in searching for new radioisotopes was simply the fascination for exploring an exciting new frontier of science. Usually, we gave little thought to the possibility that one of the objects of our search would have practical value."
"Our first immediately practical jackpot came early in the collaboration between me and Jack Livingood. We had learned that Professor George H. Whipple of the University of Rochester was hoping to have a reasonably long-lived radioisotope of iron for use in his studies of hemoglobin in human blood. A visiting chemist from England, Fred Fairbrother, had begun to collaborate with Livingood in the spring of 1937 on this problem but his visit ended before completion of the work. Livingood turned to me, and this was our second team effort."
"With some advance warning, I was able to plan the chemical separation more carefully, to guard against the mixed results from the hasty work with tin. Jack bombarded iron with 5.5 MeV deuterons in the 27-inch cyclotron. When the target came off the cyclotron, around dinner time as I remember, my chemical set-ups were ready. In my determination to make an extremely clean chemical separation into fractions containing iron and the expected transmutation products cobalt and manganese, I worked all night making precipitations and repeated reprecipitations. When Jack came to work early in the morning just as the sun was rising, I handed him the three fractions and he began his first production run was made with the cyclotron, the resulting iron-59 was sent by E.O. Lawrence to Dr. Whipple, who performed the first tracer experiments on the blood, and these experiments opened up a new era in our understanding of iron metabolism and blood formation."
"In the course of our investigation we also bombarded cobalt with neutrons and found a very long-lived radioactive isotope of cobalt, confirming the indications of others that such an isotope existed, and our later work identified this as the now well-known cobalt-60. Jack and I continued this line of investigation by bombarding pure cobalt samples, some with neutrons and some with deuterons furnished by the 27-ince cyclotron, followed by very careful chemical separation experiments. These bombardments and chemical separations took place in the summer of 1937, and by the spring of 1938 our decay and radiation absorption measurements had pretty well established the radioactive properties of cobalt-60 for which we eventually measured a half-live of 5.3 years."
"A similar pattern developed in our work on zinc-65, also carried out in 1938 while Livingood was still in Berkeley. Here we followed up on the work of others who has observed a radioisotope of zinc whit a half-life of about seven months produced by the deuteron bombardment as well as the proton bombardment of copper. Livingood prepared and bombarded a zinc target with 8 MeV deuterons in the 37-inch cyclotron and I performed the chemical separations which made it possible for us during 1938 to assign this radioactivity to zinc-65, characterize its half-life as 250 ± 5 days, and to determine the energy of the radiations, with the help of Jack’s measurements with his electroscope."
Donated by Glenn Seaborg.
- Glenn Seaborg, personal communication.
- Glenn Seaborg. Adventures in the Atomic Age. Farrar, Straus and Giroux. 2001.
- Glen Seaborg. Remarks by Dr. Glenn T. Seaborg, Chairman U.S. Atomic Energy Commission at the 17th Annual Meeting of the Society of Nuclear Medicine Washington, D.C. July 10, 1970. "Reminiscences on the Development of Some Medically Useful Radionuclides."