Journal of Radioanalytical Chemistry, Vol. 59, No 2 {1980J 309-314

NUCLEAR ACTIVATION ANALYSIS 45 YEARS AFTER GEORGE HEVESY'S DISCOVERY

RESPONSE UPON RECEIPT OF THE GEORGE HEVESY MEDAL FOR 1979

V. P. GU1NN

Department of Chemistry, University of California, 1trine, California 92717 (USAJ

(Received April 12, 1980)

First, may I say how deeply honored and pleased I feel to be selected to re- ceive the George Hevesy Medal for 1979. I am most grateful for the kind and ef- fective efforts of those esteemed peers who nominated me for the award. Their efforts are indeed heart-warming. Also, of course, I am indebted to the Editors of the Journal of Radioanalytical Chemistry, who created this award, in 1968, and to MAX PEISACH's selection committee. One of the nicest aspects of regeiving this award has been my receipt of con- gratulatory letters and telephone calls from so many good friends in the field of nuclear activation analysis, from many parts of the world - not only friends whom I see often, but also some friends whom I have not seen in years. One of the most interesting letters was one from Professor GUSTAF ARRHENIUS, of the Scripps Institution of Oceanography, who mentioned that he was closely ac- quainted with GEORGE HEVESY, when both were at the University of Stock- holm. Professor ARRHENIUS is not only an eminent scientist, but he comes from a well known eminent family of chemists, and his wife is the daughter of GEORGE HEVESY. Another aspect of my receipt of this award that has proved most interesting is that it spurred me to look into the many accomplishments of GEORGE HE- VESY. He was fantastically creative and productive. Most of us, I am sure, think of GEORGE HEVESY primarily for his origination, in 1935 (published in 1936) of a method close to our collective hearts -- neutron activation analysis. Yet only 2 of his 397 scientific publications dealt with NAA. Perhaps it will be a surprise to many, as it was to me, to learn that GEORGE HEVESY also (1) performed the first radiotracer study (with RaD, in 1913), (2) was the first to measure self-diffusion (jointly with G. GROH),

J. Radioanal. Chem. 59 {1980) 309 v. P. GUINN: NUCLEAR ACTIVATION ANALYSIS 45 YEARS

(3) discovered the element hafnium (in 1923, jointly with D. COSTER), (4) was the first to use radiotracers in biology (in 1923); (5) was the first to use radiotracers in medical research (in 1923), (6) invented the method of X-ray fluorescence (in 1931, jointly with E. ALE- XANDER), (7) invented the method of isotope dilution analysis (in 1932, jointly with R. HOBBLE), and (8) was the first to use an artifically-produced radiotracer (32p, in 1935). In 1943, he received the Nobel Prize for these many pioneering discoveries in the field of radiochemistry. GEORGE HEVESY, more correctly known as GYORGY yon HEVESY, or GEORGE de HEVESY, was Hungarian-born in Budapest in 1885. He was edu- cated in Budapest, Berlin, and Freiburg, receiving his Ph.D. in 1908. After his Ph.D., his research was conducted in Zurich, in Kadsmhe (with FRITZ HABER), in Cambridge (with ERNEST RUTHERFORD), in Vienna (with H. PANETH), in England (with H. G. MOSELY), and in Copenhagen (with NIELS BOHR). When the Nazis came to power in the 1930's, he left Germany to return to Copenha- gen, where he and HILDE LEVI originated the method of NAA in 1935. When the Nazis invaded Denmark, he fled to Sweden, to the University of Stockholm. GEORGE HEVESY died in Freiburg in 1966, almost at his 81st year. For those interested in more complete accounts of the career of this great man, four good sources are listed as Ref. 1-4 Initially, the development and application of the method of nuclear activation analysis grew slowly, since in the 1930's work was hampered by the limitations of low-flux isotopic neutron sources, early cyclotrons of limited performance, lack of detectors efficient for gamma-ray detection, and no methods for gamma-ray spectrometry measurements. Around 1945, however, the method experienced a much more rapid growth rate, brught about by the availability of the very first nuclear reactors, with their vastly higher fluxes of thermal neutrons. The Oak Ridge National Laboratory, with the world's first regularly operating reactor (the X-10 graphite-moderated, air-cooled, natural-uranium, 1012-flux reactor) became the fountainhead of the now accelerating growth rate of the methodology and ap- plications of the neutron activation analysis (NAA) method. For a number of these early years, the Oak Ridge NAA group was headed by the late GEORGE W. LEDDICOTTE, a good friend of mine for many years. Since the time that LEDDICOTTE left Oak Ridge, the NAA group there has been under the capable direction of WILLIAM S. LYON, also a good friend of mine of long standing. Today, some 35 years after it first began NAA work, the Oak Ridge group con- tinues to contribute significantly to progress in the field of NAA.

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