K. S. Krane

E2,M1 multipole mixing ratios in odd-mass nuclei, A > 150

Abstract A survey is presented of the E 2, M 1 multipole mixing ratios of gamma-ray transitions in odd-mass nuclei with A > 150. Angular distribution and correlation measurements reported in the literature have been analyzed in terms of a consistent choice of the phase relationship between the E 2 and M 1 matrix elements. Presented is a set of recommended values which is based whenever possible on an average of results from various studies. For the strongly deformed nuclei, these values are grouped and analyzed according to the Nilsson configurations assigned to the levels. In order to facilitate the analysis in terms of Nilsson states, the angular distribution and correlation data are complemented by the inclusion of some selected determinations of the multipole mixing ratios from internal-conversion-coefficient measurements. The survey includes data available in the literature up to December 1975.

E2,M1 multipole mixing ratios in even-even nuclei, A ≥ 152

Abstract A survey is presented of E2,M1 mixing ratios of gamma-ray transitions in even-even nuclei with mass numbers A ≥ 152. Angular distribution and correlation data from the literature are analyzed in terms of a consistent choice of the phase relationship between the E2 and M1 matrix elements. The cutoff date for the literature was June 1975. Based on an average of the experimental results from the literature, a recommended value of the E2,M1 mixing ratio for each transition is included.

Nuclear orientation and parity-mixing studies of the decays of 171Er and 169, 175Yb

Abstract Angular distributions of γ-radiations emitted by 171Er and 169, 175Yb have been studied from radioactive samples polarized at low temperatures. The magnetic hyperfine field of Er in ZrFe2 was deduced to be 8.3±1.0 MG, based on the anisotropies of the 171Tm γ-rays. The magnitudes of the 159Yb and 175Yb magnetic moments were deduced to be 0.63±0.09 μN and 0.40±0.05 μN, respectively, based on γ-ray anisotropies following the decay of samples polarized in Au. Gamma rays from 177Lu were observed to be emitted isotropically, indicating the lack of Lu polarization in Au. The E2/M1 and M2/E1 multipole mixing ratios were deduced for most of the mixed γ-transitions in 169, 171Tm and 175Lu. Investigations of the forward-backward asymmetry of the angular distributions of a number of strongly hindered γ-transitions in 169, 171Tm and 175Lu revealed no effect attributable to parity mixing in the nuclear states.

Iodine magnetic moments: Shape coexistence and N = 64 subshell closure

Abstract The magnetic dipole mooments of 117 I, 118 I g , 118 I m , 119 I, 120 I g , 120 I m , 121 I and 122 I have been measured by the technique of on-line low-temperature nuclear orientation. The ground-state moments show the influence of N = 64 subshell closure, with near-spherical configurations, while the moments of the metastable states suggest large prolate deformations.

Angular-correlation study of the level scheme of 193Ir

The decay of 193Os to 193Ir has been studied by γγ angular correlations. Inconsistencies between previous angular correlations, internal conversion coefficients, and nuclear orientation angular distributions have been satisfactorily resolved by the present results. These data are used to derive a set of E2M 1 multipole mixing ratios of the transitions between low-lying states. The resulting electromagnetic transition moments are compared with calculations based on the Nilsson model with Coriolis mixing and on the interacting boson-fermion model.

Nuclear orientation of 160Tb in Tb metal

Abstract The decay of 160Tb oriented at low temperatures in Tb metal has been investigated, and angular distributions of 19 γ-rays have been determined. The reduction in anisotropy in polycrystalline metal samples is discussed. Multipole mixing ratios have been determined for many of the γ-rays. A critical discussion is given of the previously reported M2 E1 mixing ratios, and previous nuclear orientation studies are re-analyzed in a consistent manner so that their results can be compared. It is shown that the nuclear orientation and angular correlation results for the 1178 keV transition are consistent only if E3/E1 mixing is present. The El branching ratios and M2 E1 mixing ratios are analyzed on the basis of Coriolis-mixed K = 0, 1 and 2 character for the negative-parity levels of 160Dy.

Regression line analysis

A computational technique is presented, suitable for small computers, of doing regression line analysis on data independent uncertainties.(AIP)

NUCLEAR ORIENTATION STUDY OF THE DECAY OF

Investigations of the angular distribution of

sup 239

\ensuremath{\gamma}

Np POLARIZED IN ZrFe

radiation from