SPALLATION AND FISSION IN THORIUM-232 AND THE MASSES OF THE HEAVIEST ELEMENTS (thesis)

Technical Report · Tue Apr 01 04:00:00 EST 1958

OSTI ID:4334919

Foreman, Jr, B M

In Part One is reported a series of experiments to measure mass yield curves for fission and excitation functions for spallation reactions induced in Th/sup 232/ by helium ions of energy 15 to 46 Mev. The fission yield curves show the usual double-humped shape indicatiag asymmetric fission, becoming more symmetric as bombarding energy is increased. The ( alpha ,4n) and fission reactions can be understood in terms of the compoundnucleus theory of nuclear reactions. The ( alpha ,p), (4,pn), ( alpha ,p2n), ( alpha ,p3n), ( alpha ,2p), ( alpha ,2pn), and (4, alpha n) excitation functions are discussed in terms of a mechanism in which one charged particle is emitted in a direct interaction, followed by the evaporation of a small number of neutrons. In Part Two, the masses of the isotopes of the heaviest elements are calculated from known decay data in the region. The data are extended by means of decay energies calculated from closed decay-energy cycles and some are estimated from the systematics of alpha- and beta-decay energies. The absolute values of the masses are based on the mass-spectrometrically dctermined mass of Pb/sup 208/ and a few measured neutron binding energies. The half-life systematics of alpha decay and spontaneous fission are also presented and some predictions are made of the properties of as yet undiscovered nuclides. (auth)

• Research Organization: California Univ., Berkeley, CA (US). Radiation Lab.
• DOE Contract Number: W-7405-ENG-48
• NSA Number: NSA-12-012785
• OSTI ID: 4334919
• Report Number(s): UCRL-8223
• Country of Publication: United States
• Language: English

Related Subjects

ALPHA BEAMS
ALPHA DECAY
ALPHA PARTICLES
BETA DECAY
BINDING ENERGY
CHARGED PARTICLES
COMPOUND NUCLEI
CROSS SECTIONS
DECAY
EFFICIENCY
ELEMENTS
EMISSION
ENERGY
ENERGY RANGE
EVAPORATION
EXCITATION
FISSION
HALF-LIFE
HELIUM
INTERACTIONS
IONS
IRRADIATION
ISOTOPES
LEAD 208
MASS
MASS SPECTROMETERS
MEASURED VALUES
NEUTRONS
NUCLEAR MODELS
NUCLEAR REACTIONS
NUCLEI
NUCLIDES
PHYSICS
PROTONS
THORIUM 232