Biographical Memoirs - Edwin McMillan

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Audience/Grade:	College Freshman - Continuing Education
Discipline(s):	Chemistry Nuclear Engineering Physics
Special Topic(s):	History of Technology
Learning Resource Type:	Reference - Article/Document
Media Type:	WWW
Author(s):	National Academy of Sciences
Description:	"After a gap in his pursuit, McMillan had become persuaded by early 1940 that the nonrecoiling 2.3-day activity just could not be the decay of a fission fragment. He began a set of experiments with the new 60-inch cyclotron and its 16-MeV deuterons. Two observations confirmed his belief as a certainty. One, using cadmium absorbers to reduce the thermal neutrons, showed greatly reduced fission activity but left the two nonrecoiling activities in the same relative proportion. The other, a fission product experiment with extremely thin collodion catcher foils, showed that the range of the 2.3-day "fragments" was less than 0.1 millimeter of air equivalent. The 2.3-day activity could not be from fission; the twenty-three-minute and 2.3-day activities almost certainly were genetically related. The beta decay of 239U was producing atoms of a new element with Z = 93! McMillan found chemically that the 2.3-day activity had some, but not all, the characteristics of a rare earth."
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Version Info
Publication Date:	2008
Platform/Format:	WWW
Cost:	Free
Download URL:	http://www.nap.edu/html/biomems/emcmillan.html
Metadata:	IEEE LOM Record
Collection:	NEEDS