Glenn Seaborg and John Livingood—Absorbers (1936-1938)
These absorbers were donated by Glenn Seaborg and identified by him as items that he and John Livingood had used at the University of California in Berkeley. This would have been between 1936 and 1938 (in late 1938 Livingood moved to Massachusetts). The small cardboard box that the copper absorbers came in has "Cu Absorbers" written on it (in Livingood's handwriting) and the box that the lead absorbers came in has "Pb absorbers" written on it. The box that the aluminum absorbers came in has "JJL" written on it.
Each absorber is 1 1/4" wide (not counting the small tab) and 2 1/2" long.
Copper absorbers: All six have ".1587 cm" scratched on them
Aluminum absorbers: four have "2.35 mm" and ".0935" scratched on them, fourteen have “.007" on them, two have ".0035" on them, and one has ".0425" on it.
Lead absorbers: these have no information on them, but two are 0.125" thick, five are 0.075" thick, and fifteen are about 0.005" thick.
Quoting some of Seaborg's presentation at the 1970 annual meeting of the Society of Nuclear Medicine "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, using a small Lauritsen quartz fiber electroscope mounted in a sort of cubbyhole room in the basement at the opposite end of LeConte Hall. Jack constructed and operated the quartz fiber electroscope with consummate skill."
The purpose of the absorbers would have been to determine the characteristics of the beta and gamma radiation emitted by the radioactive material. To be specific, they would permit an estimation of the effective energies of the radiation. In his 1933 publication "Experimental Atomic Physics," coauthored with G.P. Harnwell, Livingood describes the type of measurements these absorbers would have been used for.
Coincidently, the collection has two electroscopes that were built by Art Snell at Berkeley during this period (1937, 1938) and they came with a couple of aluminum absorbers that are exactly the same size as these ones donated by Seaborg. Learn more about Snell electroscopes. It would seem then that there was some attempt at standardizing the equipment used at Berkeley.
Donated by Glenn Seaborg.
- Glenn Seaborg, personal communication.
- 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."
- Harnwell, GP, Livingood, JJ. Experimental Atomic Physics. McGraw-Hill, New York, 1933.