/pdf/study-of-nuclear-structure-by-electromagnetic-excitation-430e7edjtf.pdf

Study of Nuclear Structure by Electromagnetic Excitation with Accelerated Ions

The measurements of the hyperfine structure of free, naturally occurring, alkali atoms are reviewed. The experimental methods are discussed, as are the relationships between hyperfine structure data and other atomic constants.

Experimental determinations of the hyperfine structure in the alkali atoms

A survey has been made of the differential scattering cross sections for 187-Mev electrons on the even-even nuclei $_{12}\mathrm{Mg}^{24}$, $_{14}\mathrm{Si}^{28}$, $_{16}\mathrm{S}^{32}$, $_{18}\mathrm{A}^{40}$, and $_{28}\mathrm{Sr}^{88}$. It has been possible to separate the elastic scattering from the inelastic in all cases and to resolve the inelastic groups from specific nuclear levels for at least one level in all cases. A simple Born-approximation analysis of the elastic data yields values of the effective radii and surface thicknesses of the nuclear charge densities which (if suitably corrected for failure of the Born approximation) are in substantial agreement with the results of Hahn, Ravenhall, and Hofstadter; i.e., a radius parameter of $c\ensuremath{\cong}1.08 {A}^{\frac{1}{3}}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}$ cm (radius to half-maximum of the charge distribution) and a surface thickness of $t\ensuremath{\cong}2.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}$ cm (thickness from 10% to 90% of the maximum of the charge distribution). Phenomenological analysis of the inelastic scattering along the lines laid down by Schiff yields some tentative multipolarity assignments, and application of some results of Ravenhall yields estimates of (radiative) partial level widths; for the $E2$ transitions these correspond to lifetimes of \ensuremath{\sim}19\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ sec (Mg 1.37 Mev) to \ensuremath{\sim}1.4\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ sec (Sr 1.85 Mev). The observed strengths of the transitions are compared to those predicted by Weisskopf theory.

Inelastic and Elastic Scattering of 187-Mev Electrons from Selected Even-Even Nuclei

(1966). Electron scattering and nuclear structure. Advances in Physics: Vol. 15, No. 57, pp. 1-109.

https://www.annualreviews.org/doi/pdf/10.1146/annurev.ns.25.120175.001553

Electron Scattering and Nuclear Structure

Electron scattering and nuclear structure.

Internal conversion coefficients

Consideration of a number of problems which arise in the analysis of angular correlation and angular distribution data is given. These include corrections for finite angular resolution. For a source of constant strength the questions of determination of most probable counting rates, their associated errors and the determination of the most probable coefficients in the Legendre representation of the data, as well as the errors in the determination of these coefficients, are examined. A brief discussion of the corrections for a decaying source is also presented.

The analysis of angular correlation and angular distribution data

The electron-positron angular correlation and total conversion coefficient are calculated for internal pair formation and for arbitrary multipole order of the electric and magnetic radiation fields The Born approximation is used and in the region of greatest experimental interest, $Z\ensuremath{\lesssim}40$ and gamma-ray energyg25 Mev, the consequent error should be negligible Numerical results are given for multipole fields of order ${2}^{l}$ with $l=1$ through 5 inclusive

Internal pair formation

The internal conversion coefficients for electric and magnetic multipole radiation have been computed for the $K$-shell in the relativistic case with the unscreened coulomb field acting on the electron. The numerical results, which are obtained to four-significant-figure accuracy, were computed on the automatic sequence relay calculator (Mark I) and are given here for 12 values of $Z$ in the range $10l~Zl~96$ and 6 gammaray energies (between $0.3 m{c}^{2}$ and $5.0 m{c}^{2}$) for the first five electric and first five magnetic multipoles.

The internal conversion coefficients. i. the k-shell

The electron-positron angular correlation and total conversion coefficient are calculated for internal pair formation and for arbitrary multipole order of the electric and magnetic radiation fields. The Born approximation is used and in the region of greatest experimental interest, Z≲40 and gamma-ray energy>2.5 Mev, the consequent error should be negligible. Numerical results are given for multipole fields of order 2l with l=1 through 5 inclusive.

M. E. Rose

Papers

Internal conversion coefficients

The analysis of angular correlation and angular distribution data

Internal pair formation

The internal conversion coefficients. i. the k-shell

Internal Pair Formation