FISSION FRAGMENT ANGULAR DISTRIBUTIONS AND SADDLE DEFORMATIONS

Journal Article · Sun Apr 01 04:00:00 EST 1962 · Physical Review (U.S.) Superseded in part by Phys.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.126.220· OSTI ID:4831061

Chaudhry, R; Vandenbosch, R; Huizenga, J R

The fission fragment angular distributions are measured with solid-state detectors for helium-ion-induced fission of bismuth, Pb/sup 206/, thallium, and gold. The measurements are made at helium-ion energies between 30 and 43 Mev. With 42.8-Mev helium ions the relative differential fission cross sections for gold and bismuth targets are measured at angles between 90 and 180 deg and the resulting angular distributions fitted by a least-squares method with Legendre polynomials. The W(174.5 deg )/W(90 deg ) ratios for 42.8-Mev helium-ion-lnduced fission of bismuth, lead, Pb/sup 206/, thallium, and gold are 2.26 plus or minus 0.07, 2.47 plus or minus 0.08, 2.46 plus or minus relative fission cross sections at 174.5 and 90 deg are also measured at several lower helium-ion energies for all targets except natural lead. These data are utilized in the calculation of the energy dependence of K/sub o/, the standard deviation of the distribution in the angular-momentum projection on the nuclear symmetry aixs at the saddle point The energy dependence of K/sub o/ deduced from the experimental anisotropy measurements is similar to the predicted energy dependence from statistical theory if the nuclear temperature at the saddle point is proportional to the square root of the excitation energy. These results indicate that the effective moment of inentia is independent of excitation energy. With the assumption that the effective moment of inertia at the saddle point deformation (which is deduced for each target from the anisotropy measurement at the highest energy) is the rigid-body value, the stretching at the saddle point is calculated for various simple geometric configurations. For a saddle configuration of two equal tangent spheroids, the stretchings necessary to produce the observed effective moments of inertia are in agreement with liquid drop model calculations. (auth)

• Research Organization: Argonne National Lab., Ill.
• NSA Number: NSA-16-018493
• OSTI ID: 4831061
• Journal Information: Physical Review (U.S.) Superseded in part by Phys.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: 126; ISSN PHRVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ANGULAR DISTRIBUTION
ANISOTROPY
BISMUTH
CROSS SECTIONS
CRYSTALS
DEFORMATION
ENERGY
ENERGY RANGE
EXCITATION
FISSION
FISSION PRODUCTS
FUNCTIONS
GOLD
HELIUM
IONS
LEAD 206
LEAST SQUARES
LEGENDRE FUNCTIONS
LEGENDRE POLYNOMIALS
MASS
MATHEMATICS
MEASURED VALUES
MOMENT OF INERTIA
MOMENTUM
NUCLEAR MODELS
NUCLEI
NUMERICALS
PHYSICS
RADIATION DETECTORS
THALLIUM
VARIATIONS