Calculation of the Spin- and Energy-Dependent Fission Widths for 233U, 235U, 239Pu and 241Pu from Channel Theory

The spin- and energy-dependence of the fission widths are estimated for 233U, 235U, 23, Pu and 241Pu from the channel theory of nuclear fission. The spin-dependent fission widths are deduced, by assuming the appropriate transition state spectrum, and the fission and capture cross sections are calculated with these fission widths. The results thus derived agree well with the experimental data which differ distinctively from nuclide to nuclide, and this is despite closely similar transition state spectra assumed for the different nuclides. This fact supports the validity of the spin-dependent fission widths derived from channel theory. The ratio for the states due to s-wave neutrons are as follows: 2.5 for 233U, 1.8 for 235U, between 74 and 210 for 239Pu and 2.4 for 241Pu. The fission widths of 239Pu are thus seen to have exceptionally strong spin-dependence compared with the other nuclides.

[1]  E. F. Groh,et al.  Null-Reactivity Measurements of Capture/Fission Ratio in 235U and 239Pu , 1970 .

[2]  J. Schmidt.  Aktueller Stand der physikalischen Kenntnis der wichtigsten Reaktorkerndaten , 1969 .

[3]  H. Kuroi,et al.  Integral Experiment and Cross Sections of 239Pu in the Intermediate Energy Region , 1969 .

[4]  J. Lynn.  INTERPRETATION OF NEUTRON-INDUCED FISSION CROSS SECTIONS AND RELATED DATA. , 1968 .

[5]  E. Migneco,et al.  Resonance grouping structure in neutron induced subthreshold fission of 240Pu , 1968 .

[6]  M. G. Silbert,et al.  RESONANCE ANALYSIS OF THE $sup 233$U FISSION CROSS SECTION. , 1968 .

[7]  E. M. Page,et al.  ANALYSIS OF SODIUM REACTIVITY MEASUREMENTS. VOLUME I. CROSS SECTION EVALUATION AND DATA TESTING. , 1968 .

[8]  H. Weigmann.  An interpretation of the structure of subthreshold fission cross section of240Pu , 1968 .

[9]  B. Hutchins,et al.  IMPLICATIONS OF RECENT FAST CRITICAL EXPERIMENTS ON BASIC FAST REACTOR DESIGN DATA AND CALCULATIONAL METHODS. , 1967 .

[10]  S. Tretyakova,et al.  Excitation energy of spontaneously fissioning isomer 242mAm , 1967 .

[11]  V. Strutinsky,et al.  Shell effects in nuclear masses and deformation energies , 1967 .

[12]  J. Nix.  The normal modes of oscillation of a uniformly charged drop about its saddle-point shape , 1967 .

[13]  R. Albert.  U 233 Fission Cross Section Measured Using a Nuclear Explosion in Space , 1966 .

[14]  J. Lynn.  ANALYSIS AND INTERPRETATION OF THE SLOW NEUTRON CROSS SECTIONS OF THE FISSIONABLE NUCLEI , 1964 .

[15]  J. Griffin.  TRANSITION STATES AT THE FISSION BARRIER , 1964 .

[16]  J. Griffin.  NUCLEAR SUPERFLUIDITY AND STATISTICAL EFFECTS IN NUCLEAR FISSION , 1963 .

[17]  W. Gibbs,et al.  EVIDENCE FOR NUCLEAR PAIRING EFFECTS AT THE FISSION BARRIER , 1963 .

[18]  S. Johansson.  Nuclear octupole deformation and the mechanism of fission , 1961 .

[19]  R. B. Nicholson.  The Doppler Effect in Fast Neutron Reactors , 1960 .

[20]  R. Stokes,et al.  MEASUREMENT OF THE FISSION THRESHOLDS OF Pu$sup 230$, U$sup 233$, U$sup 238$ USING THE (d,p) REACTION , 1959 .

[21]  D. J. Hughes,et al.  Neutron cross section , 1955 .

[22]  John Archibald Wheeler,et al.  NUCLEAR CONSTITUTION AND THE INTERPRETATION OF FISSION PHENOMENA , 1953 .

[23]  Niels Bohr,et al.  The Mechanism of nuclear fission , 1939 .

[24]  Hans A. Bethe,et al.  Nuclear Physics B. Nuclear Dynamics, Theoretical , 1937 .