Jirina Stone

Abstract:

The anisotropy in the directional distribution of gamma-rays from the decay of152,154Tb oriented in a gadolinium matrix at low temperatures, has been measured at the angles of 0 and π/2 with respect to the applied magnetic field direction at temperature of (15±1) mK. Unambiguous values of spin have been deduced for several levels in152Gd. Multipole mixing ratios of many gamma-ray transitions occurring in152Gd have been found and results are compared with the similar transitions in150,154,156Gd and they are discussed in terms of the rotational-vibrational model and dynamic deformation theory based on the Strutinsky method. Our results confirm the spin value of 0 for 21·4 h isomer in154Tb and they establish the spin value of 3 for the 2277·0 and 2336·1 keV levels and the spin value of 4 for the 2416·3 keV level in154Gd. © 1981 Academia, Publishing House of the Czechoslovak Academy of Sciences.

Abstract:

The anisotropy of the angular distribution of gamma-rays from the decay of¹⁵⁶Tb, oriented in a gadolinium matrix at low temperatures, has been measured at the angles of 0 and π/2 with respect to the applied magnetic field direction in the range of temperatures from 14·6 to 68·4 mK. The temperature dependence of anisotropy was measured for the first time. The parameters of hyperfine magnetic dipole and electric quadrupole splittings have been determined and the values of the magnetic dipole moment |Μ¹⁵⁶|=(9·6±1·3)×10^-27 J/T and the electric quadrupole moment Q¹⁵⁶=(2·9±0·9)×10^-28 m² of the¹⁵⁶Tb ground state have been calculated. Multipole mixing ratios and B(E2) branching ratios of many gamma-ray transitions occurring in¹⁵⁶Gd have been found and the results have been discussed in terms of the rotational-vibration and pairing-plus-quadrupole models. © 1979 Academia, Publishing House of the Czechoslovak Academy of Sciences.

Abstract:

The decay of161Gd has been studied using Ge(Li) detectors. The single and coincidence gamma-ray spectra were measured. In comparison with the previous studies more precise gammaray energies and relative intensities are reported. Five formerly unreported weak transitions at 97·0, 152·0, 168·0, 346·0 and 417·0 keV have been assigned to the161Gd decay. The properties of excited levels in the161Tb nuclei are discussed in terms of the collective nuclear model. The effect of the Coriolis coupling has been considered. © 1976 Academia, Publishing House of the Czechoslovak Academy of Sciences.