Showing papers by "Glenn T. Seaborg published in 2008"
20 May 2008
TL;DR: Thomas and Seaborg as mentioned in this paper were among the participants in the ASTATINE COMPOUND NUCLEI FORMED BY HEAVY-ION BOMBARDMENT.
Abstract: UCRL-9950 UNIVERSITY OF CALIFORNIA La,~ence Radiation Laboratory Berkeley) California Contract No. 7405-eng-48 SPALLATION-FISSION COMPETITION IN ASTATINE COMPOUND NUCLEI FORMED BY HEAVY-ION BOMBARDMENT T. Darrah Thomas) Glen E. Gordon) Robert M. Latimer) and Glenn T. Seaborg November 1961
21 citations
TL;DR: This is a Library Circulating Copy which may be borrowed for two weeks.
Abstract: UCRE /a2 6 p// c.2 NIVERSITY OF CALIFORNIA AIJC 2 LIBRAr-cY ~i\ili DOCUMENTS SECTION TWO-WEEK LOAN COPY This is a Library Circulating Copy which may be borrowed for two weeks. BERKELEY, CALIFORNIA
6 citations
TL;DR: In this article, it was shown that fission occurs either with comparable magnitudes in several nuclei in the neutron-evaporation chain, or preferentially in one or two nuclei near the end of the chain, rather than predominantly in the initial compound nucleus.
Abstract: Cross sections for neutron-evaporation reactions from compound nuclei produced by bombardment of gold with carbon ions and of platinum with nitrogen ions have been determined. The magnitudes of the cross sections are considerably lower than would be predicted on the assumption that neutron emission is the only important mode of decay of the intermediate nuclei. This observation is explained on the basis of fission competition with neutron emission. To a much lesser extent, charged-particle evaporation is also a competing mode of decay. The arguments presented indicate that fission occurs either with comparable magnitudes in several nuclei in the neutron-evaporation chain, or preferentially in one or two nuclei near the end of the chain, rather than predominantly in the initial compound nucleus. Problems arising from the possible existence of isomers in the odd-odd astatine nuclides are discussed.
1 citations
TL;DR: In this paper, the angular distribution and kinetic energy spectra of fragments were obtained from two types of detectors, gas scintillation chambers and silicon p-n junctions, and the average excitation energy of the fissioning nucleus at the time of fission was obtained.
Abstract: Angular distribution and kinetic-energy spectra of fragments, and cross sections for fission of gold with 68- to 124-Mev C{sup 12} ions have been obtained by observation of the fragments in two types of detectors, gas scintillation chambers and silicon p-n junctions. From the parameters used to fit the angular distributions to the theoretical curves of Halpern and Strutinski, we have obtained the average excitation energy of the fissioning nucleus at the time of fission. This quantity is approximately 25 Mev, which is nearly independent of bombarding energy, suggesting that fission is preceded by the emission of several particles from the compound nucleus. The fission cross section increases from a value of 100 mb at 68 Mev to 1.28 b. at 124 Mev. Over this range of bombarding energies, the total fragment kinetic-energy release rises from 142 {+-} 6 to 146 {+-} 6 Mev. At all bombarding energies, the variation of laboratory-system kinetic energy of the fragments with laboratory-system angle indicates full momentum transfer by the bombarding particle to the fissioning system.