Konversionselektronen von 156Gd nach Neutroneneinfang / The Conversion Electron Spectrum of the Reaction 155Gd(n,e)156Gd

The conversion electron spectrum of the reaction 155Gd (n, e) 156Gd has been measured up to 8.5 MeV. The results below 4.5 MeV are presented and multipolarities are determined with these results. E0 admixtures of the Δ I = 0 transitions from the 0 + β-vibrational band to the ground state band were determined with 15% accuracy. 156Gd level schemes are discussed and extended by new spin and parity assignments.

Untersuchungen zum Niveauschema von 152Eu mit Konversionselektronen nach Neutroneneinfang / Studies of the level scheme of 152Eu by neutron capture conversion electrons

With the beta-spectrometer at the research reactor near Munich the conversion-electron spectrum of 152Eu from slow neutron capture has been measured. In the range between 0 and 350 keV approximately 500 lines were found. For the low-energy-states a level scheme is proposed and compared with earlier level schemes of 152Eu. New transitions for the 9.3 h-isomer were found.

Anomalous line shapes in the internal conversion electron spectrum from 227Th

The conversion electron spectra of the 29.9 and 31.6 keV transitions in 223Ra which are excited by the α decay of 227Th have been studied using the Chalk River [Formula: see text] spectrometer. The shapes of the L and M subshell conversion lines of the 29.9 keV transition differ significantly from those of the corresponding lines of the 31.6 keV transition. This observation confirms the difference in line shapes first reported by Valadares, Walen, and Briancon. The conversion electron spectra which are coincident with α particles which penetrated normally through the source backing have also been measured. The coincidence arrangement selects the component of the conversion electron spectrum contributed by atoms recoiling freely into the spectrometer vacuum. The conversion lines of the 31.6 keV transition appear as single doppler-shifted components which are displaced toward higher momentum relative to the main peaks of the singles spectrum. The conversion lines of the 29.9 keV transition have a more complex structure. The doppler-shifted peak is less pronounced for these lines and 68 ± 10% of the intensity in these coincidence spectra appear in broad momentum distributions lying some hundreds of electron volts lower in energy than the doppler-shifted peak. These observations provide support for the explanation which Valadares, Walen, and Briancon have advanced to account for the anomalous appearance of the conversion lines of the 29.9 keV transition in their singles spectra. From the coincidence spectra measured in this work together with results from the charge state studies of Perrin and de Wieclawick, we infer that the LII, LIII, and MIII binding energies in 223Ra atoms of mean charge + 12 are 239 ± 32, 216 ± 25, and 212 ± 38 eV higher than the corresponding binding energies in 223Ra atoms of mean charge + 1.

On the Decay of 165Dy

The internal conversion electron spectrum of transitions in the decay of (139 min) 165Dy to 165Ho has been studied using a high resolution iron-free double focusing β-ray spectrometer. In addition to γ rays previously reported eight new γ rays, mostly in the low energy region, have been observed. A decay scheme involving 17 excited levels is proposed for 165Ho. Multipolarity data, obtained from the measurements of absolute or ratios of conversion coefficients of γ rays, were utilized for assigning possible spins and parities to the levels of 165Ho. The experimental level structure is discussed in the light of nuclear models.

The Internal Conversion Electron Spectrum of 147Nd

The internal conversion electron spectrum following the β-decay of 147Nd has been studied using, an iron yoke and an iron free double focussing β-ray spectrometer at a momentum resolution of about 0.2%. A total of 66 transitions has been ascribed to this decay. On the basis of statistical analysis of sum relationships for the transition energies, combined with earlier reported coincidence results, a decay scheme involving 16 excited levels is suggested. The experimental data indicate a higher state at 763 keV. Its energy is close to the high state observed in other promethium nuclei.The multipolarity assignment for each transition was obtained by comparing the observed conversion line intensity ratios with the theoretical line intensity ratios of SLIV and BAND. From the multipolarity values obtained, the spins and parities of the excited levels in 147Pm are assigned and discussed in terms of recent nuclear models.