Nuclear Data Sheets. Section A最新文献

Nuclear cross sections for charged-particle-induced reactions of isotopes of N and O are presented in tabular and graphical form. This compilation includes experimental cross-section data available in the literature before January 1, 1965, for nuclear reactions of the type A(a,b)B at all energies, where M_a ≥ one nucleon mass. Nuclear reactions involving mesons in the exit channel are not included. This collection supplements a previous compilation, Los Alamos Scientific Laboratory Report LA-2014 (see following page for bibliographic information). A large amount of the cross-section data is not presented either in tabular or graphical form in order to limit the size of the present compilation to a manageable one. A number of annotated bibliographies are included in the appendixes to provide a brief summary of these data.

Basic formulas and tabulations of numerical coefficients are provided for the analysis of data on angular correlations of successive radiative transitions from aligned nuclei. The formulas are extracted from an earlier published development of the angular-correlation formalism. This development is based upon a factored version of the equations which is used to extend the application from the usual two-step cascade to general multiple-step cascades. The resulting flexibility and greater efficiency of the formalism are utilized to provide an extensive tabulation of coefficients for a variety of specific applications. Coefficients are provided for analysis in terms of either the population parameters or the statistical tensors of the aligned state. The coefficients can be used for the analysis of angular distributions, linear polarizations, and triple correlations involving one or more intermediate unobserved radiations. In contrast to previous tabulations of coeeficients for angular-correlation analysis, the range of the present tables has been extended to include multipolarities through octupole. The overall length of the tables, however, remains about the same as previous tables because of the greater efficiency of the factored formalism. The range of spins covered by the tables are J ≤ 11/2 for the initial aligned stae and J ≤ 21/2 for the final state of cascade.

Data on absolute electromagnetic transition rates in nuclei of the 1p- and 2s1d-shells are presented. Table I lists the experimental results for partial widths with quoted errors, transition strengths, and reduced transition probabilities. This table also contains averages and mean errors of the averages in cases where more than one experimental result on a certain transition is available.

Table II contains additional information, mainly mixing ratios which were used to calculate transition strengths in mixed transitions, as well as widths or lifetimes which could not be further reduced. Branching ratios are not listed.

Table III presents a survey of mean transition strengths and of standard deviations from the mean values for the various multipole types of transitions, subdivided according to the isospin selection rules.

The distributions of the transition strengths are presented in a number of histograms. The dependence of the transition strengths on the mass number and excitation energy, as well as T-forbiddeness factors, are discussed and in some cases graphically illustrated.

The SU₃ fractional-parentage and Clebsch-Gordan coefficients in the 2s-1d shell have been calculated numerically for systems of up to six nucleons. The classification scheme of the states is characterized by the group chain SU₈ ⊃ SU₃ ⊃ R₃, and the basis functions are represented in a completely orthogonal system. A new reciprocity relation (phase convention) for the Clebsch-Gordan coefficients is proposed and adopted in the tabulation. A table of the coefficients of fractional parentage is presented here. A sample of the table of Clebsch-Gordan coefficients is given. The complete table is available from the American Documentation Institute Auxiliary Publications Project.^b.

Tables of deuteron absorption coefficients and reaction cross sections are presented for C, Mg, Ni, Rh, Nd, and Au at deuteron energies of 4 to 28 MeV. These were obtained from optical model calculations using parameters previously published by the authors.⁴

Optical model calculations for neutron differential elastic scattering cross sections and total cross sections have been made for the following target nuclei at selected neutron energies between 0 and 16 MeV: ^6,7Li, ⁹Be, ^10,11D, ¹²C, ¹⁴N, ¹⁵O, ²³Na, ²⁴Mg, ²⁷Al, ²⁸Si, ³⁵Cl, ³⁹K, ⁴⁰Ca, ⁴⁸Ti, ⁵¹Vi, ⁵²Cr, ⁵⁵Mn, ⁵⁶Fe, ⁵⁸Ni, ⁵⁹CO, ⁶²Ni, ⁶⁹Ga, ⁸⁰Se, ⁸⁹Y, ⁹³Nb, ⁹⁸Mo, ¹⁰³Rh, ¹¹⁴Cd, ¹¹⁵In, ¹¹⁸Sn, ¹²⁷I, ¹⁸⁴W, ²⁰⁸Pb, ²⁰⁹Bi, ²³²Th, ^{234,23,236,237,238}U, ^{239, 240}Pu Comparison is made with experimental data.

A compilation of information on the measured shapes of beta spectra is given. It contains, whenever possible, the numerical coefficients describing the “correction factor,” C(W) = N_m(W)/N_th(W), where Nm(W) is the measured energy spectrum and N_th (W) is an appropriate theoretical energy spectrum. The information was collected from publications that date roughly between 1957 and July 1966.