FISSION OF URANIUM-238 WITH CARBON IONS

Journal Article · Fri Sep 15 04:00:00 EDT 1961 · Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRev.123.2112· OSTI ID:4833013

Sikkeland, T; Larsh, A E; Gordon, G E

Angular distributions and kinetic-energy spectra of fragments, and cross sections for fission of U/sup 238/ with 63- to 124-Mev C/sup 12/ ions, were measured with the use of a silicon p-n junction detector. The distributions were analyzed in terms of the formation of a compound nucleus and subsequent decay by evaporation of neutrons in competition with fission. The percent fission from each isotope in the evaporation chain was calculated and the over-all angular distribution estimated with the use of the theoretical curves of Halpern and Strutinski. At the highest bombarding energies, the observed angular distributions were found to be more nearly isotropic than predicted. The mean linear momentum of the fissioning nucleus appears to be less than that of the heavy ion. A possible explanation for these discrepancies is that before the fission event there is competition from reactions in which particles are emitted in the forward direction. The contribution from this kind of reaction is estimated to be of the order of 30% at 95 and 124 Mev. Over the entire range of bombarding energies, the most probable total kinetic energy release is 186 plus or minus 6 Mev. By correspondence this suggests that the fissioning nuclei are californium isotopes. The fission cross section increases from a value of 40 mb at 63 Mev to 2.4b at 124 Mev. The experimental fission cross sections agree well with the cross sections for compound-nucleus formation calculated by use of a squarewell nuclear potential with a radius parameter r/sub 0/ = 1.5 x 10/sup -13/ cm. (auth)

• Research Organization: Univ. of California, Berkeley
• NSA Number: NSA-15-031665
• OSTI ID: 4833013
• Report Number(s): UCRL-9540; 0031-899X
• Journal Information: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 123; ISSN PHRVA
• Country of Publication: United States
• Language: English

Related Subjects

ANGULAR DISTRIBUTION
ANISOTROPY
CALIFORNIUM
CARBON 12
COMPOUND NUCLEI
CROSS SECTIONS
DECAY
DETECTION
ENERGY
ENERGY RANGE
EVAPORATION
EXCITATION
FISSION
FISSION PRODUCTS
ION BEAMS
ISOTOPES
MEASURED VALUES
MEV RANGE
MOMENTUM
NEUTRONS
NUCLEAR MODELS
NUCLEAR POTENTIAL
NUCLEAR RADII
NUCLEI
NUMERICALS
PHYSICS
SEMICONDUCTORS
SILICON
SPECTRA
TARGETS
URANIUM 238