Academic journal article Proceedings of the American Philosophical Society

Philip Hauge Abelson

Academic journal article Proceedings of the American Philosophical Society

Philip Hauge Abelson

Article excerpt

27 APRIL 1913 * 1 AUGUST 2004

PHILIP HAUGE ABELSON had at least nine scientific lives: as physicist, nuclear chemist, engineer, submarine designer, biophysicist, biogeochemist, science administrator, editor, and writer. Not only was his range of interests expansive, but he left an important mark on everything he did. He was always more interested in the future of science than in what was already known.

Abelson was born on 27 April 1913 in Tacoma, Washington, to Norwegian immigrants. He began his academic studies in chemical engineering at Washington State College (now University) in Pullman, Washington, but soon moved to chemistry. Following graduation in 1933, he remained at Washington State to work in solid state physics with Paul Anderson, ultimately receiving a master's degree in 1935. Abelson then joined the group assembled by Ernest O. Lawrence at Berkeley for his Ph.D. studies. Lawrence was developing increasingly powerful cyclotrons for the conduct of seminal studies in nuclear physics. His group included many scientists now seen as giants in the field: Robert Oppenheimer, Luis Alvarez, Edwin McMillan, and others. As a graduate student, Abelson commenced the overload of activities that was a common theme throughout his life, somehow simultaneously pursuing his graduate studies, spending fifteen hours a week as a teaching assistant, and serving on duty at the cyclotron for thirty hours per week.

The cyclotron was used to bombard various elements with neutrons, some of which might be captured and yield new isotopes. In many cases the isotopes were radioactive, undergoing a beta decay that would yield an element with a higher atomic number than the original target. As it happened, Abelson was assigned to study uranium, the heaviest element with significant natural concentrations on earth. Irradiation of uranium produced radioactive materials with many different half-lives, suggesting to some that a new and heavier element had been produced. Lawrence was skeptical, but the challenge was to separate and identify the irradiation products. Abelson focused on one of the products that produced X-rays upon decay. In order to generate enough of the material, he needed to irradiate a large volume of uranium. His mother had sent him money for a new suit, but instead he purchased uranium at a scientific supply house. He purified the uranium and built a spectrometer to characterize the X-ray emissions of the irradiated product.

As it turned out, some of the products of neutron irradiation of uranium were not the result of beta decay, but instead were the result of an entirely different process-the fissioning of ^sup 235^U to produce products of lesser atomic number, accompanied by the release of substantial energy.1 Just as Abelson was undertaking his project, word leaked out that work in Europe by Hahn and Meitner had demonstrated the fissioning of uranium. When these results were confirmed by Richard Roberts of the Carnegie Institution, the story was published in the Washington Evening Star and was read by Luis Alvarez as he was having his hair cut at the Berkeley student union. He ran to the Radiation Lab and found Abelson at the cyclotron. Abelson had just missed the discovery of this paradigm-shifting result. Abelson promptly completed his work and determined from the study of the X-ray emissions that iodine is a fission product, providing the first chemical confirmation of the HahnMeitner results and discovering a different fission product.

On receipt of his Ph.D., Abelson had several job offers. He decided to join the Department of Terrestrial Magnetism (DTM) of the Carnegie Institution to work in nuclear physics with Roberts and the department's director, Merle A. Tuve. Although the main products of the neutron irradiation of uranium were fission products, the possibility still existed that elements of higher atomic number were also produced. Two radioactive products of uranium irradiation were not accompanied by substantial energy production. …

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