T. I. Kracíková

The decay of109gPd

The decay of 13·5 h109gPd has been investigated using high resolution Ge(Li) singles γ-ray spectrometers and Ge(Li)-Ge(Li) coincidence technique. A total of 31 γ-rays of109gPd was observed. The experimental K-conversion coefficients for 19 γ-transitions were determined. Detailed quantitative information on γ-γ coincidences was obtained. The decay scheme of109gPd is presented.

The decay of111gPd and111mPd

The decays of 23·4 min111gPd and 5·5 h111mPd have been studied using high-resolution Ge(Li) singles γ-ray spectrometers and Ge(Li)-Ge(Li) coincidence system. About 140γ-rays were observed in the decays of both isomers. The half-life of111gPd was remeasured and found to be 23·4±0·2 min. The111Ag level scheme and the decay scheme of daughter 74 s111mAg were examined.

On the magnetic dipole moment of the153Tb ground state

Temperature dependence of the angular distribution anisotropy of the 212·0 keV gamma-ray following the decay of153Tb oriented in a gadolinium host was measured at temperatures from 16 to 70 mK. Magnetic dipole hyperfine splitting parameter a0 for153Tb(Gd) and magnetic dipole moment of the153Tb ground state were estimated to be ¦a0¦≧1·2×10−5 eV and ¦μ¦≧≧3·1 nuclear magnetons, respectively.

Nuclear orientation study of155Tb decay

The angular distribution of gamma-rays following the electron capture decay of155Tb nuclei oriented in a gadolinium host has been studied at temperatures between 16 and 80 mK. The magnetic dipole hyperfine splitting parameter for155Tb(Gd) has been deduced and the value of the magnetic dipole moment of155Tb ground state has been found to beμ=2.0(2)μN. The multipole mixing ratios have been determined for 9 gamma-transitions in155Gd.

The decay of 22·1 min83gSe and 69·2 SEC83mSe to the levels of83Br

The decay of83Se isomers has been studied using Ge (Li) detectors and multi-parameter analyser system. In the case of83gSe decay, it was possible to observe coincidences in Ge (Li) -Ge (Li) configuration. A total of 90 γ-rays are assigned to the decay of83gSe and 25 to that of83mSe. The half-lives of83gSe and83mSe are found to be 22·1±0·1 min and 69·2±0·6 sec, respectively. Excited states of83Br are observed at 356·74, 799·2, 866·9, 988·1, 1030·8, 1053·9, 1092·1, 1352·7, 1420·9, 1439·0, 1660·4, 1701·5, 1804·7, 1810·4, 1915·6, 2051·9, 2058·7, 2398·2, 2647·2, 2694·3, 2738·3, 2777·5, 2946·7 and 3137·8 keV. The log ft values for the branching to the excited levels of83Br are established and spin-parity assignments for these levels are deduced.

The decay of110mAg to110Cd

The gamma-ray spectrum of the decay of110mAg has been measured with the Ge(Li) detectors. A total of 32 gamma rays associated with the decay of110mAg have been observed and their intensities determined. A number of gamma-ray transitions have not been observed previously. The K-electron internal conversion coefficients were found from the relative gamma intensities used in conjunction with published K-conversion electron intensities.It is proposed that the level scheme of110Cd has new levels at 1410·4, 1443·2 and 2237·7 keV in addition to the previously known levels. The spins and parities of the new levels are discussed.

Nuclear orientation of radioactive nuclei. The spin project

Based on the state of the art of technological achievements new complementary nuclear orientation facilities - the SPIN facilities-are developed and constructed at the Joint Institute for Nuclear Research (JINR) in Dubna and at the Faculty of Mathematics and Physics of Charles University in Prague. These facilities together with the existing and planned JINR radioactive beam complexes YASNAPP and DRIBs will open new horizons for many new experiments with oriented nuclei in a broad range of atomic and mass numbers and nuclear half-lives. This will enable to accomplish a rich program in nuclear and solid state physics research-the SPIN program at JINR.

Orientation of radioactive nuclei

Two complementary low temperature nuclear orientation facilities are being developed at JINR Dubna and at the Faculty of Mathematics and Physics of Charles University in Prague, respectively. These Facilities together with existing and planned JINR radioactive beam complexes YASNAPP and DRIBs will allow accomplish rich program in nuclear and solid state physics research. The method based on hyperfine interactions at low temperatures obtained with fast cooling top loading 3He-4He dilution refrigerators is used to orient radioactive nuclei. Using on-line coupling of the isotope production, mass separation and implantation of radioactive nuclei beams into a suitable host placed in the 3He-4He dilution refrigerator, studies of isotopes with life-times as low as 1 sec can be performed. With off-line coupling isotopes with life-times down to 1 hour can be oriented. The directional distribution and temperature dependence of the radiation from oriented nuclei as well as nuclear magnetic resonance on oriented radi...