G. Malmsten

L subshell ratios in some pure E2 transitions

Abstract The L subshell conversion line intensity ratios have been studied for four 2 + → 0 + transitions (86.79 keV in 66 160 Dy, 80.57 keV in 68 166 Er, 84.26 keV in 70 170 Yb and 100.09 keV in 74 182 W) and for the 5 2 − → 1 2 − 99.07 keV transition in 74 183 W. The L II /L III ratios obtained agree very well with theory but the L I /L II and L I /L III ratios are 5–9% higher than the theoretical ratios. Deviations of the same magnitude have also been reported by other research groups.

The decay of 140La

Abstract The beta-ray and internal-conversion spectra from the decay of 140 La to 140 Ce have been investigated using double-focussing spectrometers. Beta branches with end-point energies 2166±7, 1674 ± 10, 1354 ± 15 and 1244 ± 20 keV have been established, giving a Q -value of 3762 ± 8 keV. In the internal conversion spectrum, 26 transitions have been found ranging in energy from a previously not reported 24.595 ± 0.004 keV transition up to a very weak transition at 3322 ± 4 keV. The gamma-ray spectrum following the decay of 140 La has been studied using a Ge(Li) detector. The theoretical K-conversion coefficient for the 1596 keV E2 transition has been used to calculate conversion coefficients. From these coefficients together with K//∑L and L-subshell ratios, probable multipolarity assignments have been obtained for most of the transitions. All transitions observed have been fitted into a tentative decay scheme.

K/L, LIII/MIII and M/(N + O + P) ratios in pure E2 transitions☆

Abstract Accurate measurements have been performed on relative K, L, M and (N + O + P) internal conversion line intensities of some pure E2 transitions in nuclei in the rare-earth region. The results are compared with theoretical values obtained from the calculations by Rose, Sliv and Band, Hager and Seltzer and by Bhalla. Good agreement between experiment and theory is found for the K/L ratios, while the experimentally obtained LIII/MIII ratios are somewhat lower than predicted by theory.

An internal conversion study of the decay of193Au

The internal conversion spectrum following the decay of193Au has been studied in the electron energy region 0.8 to 700 keV, with the use of high-resolution magnetic beta-ray spectrometers. Several not previously reported transitions have been estabblished. Multipolarities and mixing ratios have been deduced fromK/L and subshell intensity ratios, and the majority of the transitions were found to be ofM1 and/orE2 characters. A revised level scheme for193Pt, which consistently accomodates most transitions, has been constructed. Tentative spin-parity values have been assigned to all levels.

DETERMINATION OF RELATIVE INTENSITIES OF M INTERNAL CONVERSION LINES IN PURE E2 TRANSITIONS.

Accurate measurements have been performed on the relative intensities of the M internal conversion lines of three pure E2 transitions in nuclei in the rare-earth region. The results are compared with theoretical values obtained from the calculations by Bhalla and by Hager and Seltzer. Discrepancies of about 6% between experiment and theory are reported for the MI/MII and MI/MIII ratios of the 80.57 keV transition in 166Er. The MII/MIII ratios of the 84.26 keV transition in 170Yb and of the 100.09 keV transition in 182W are significantly lower than predicted by theory.

Internal conversion studies of the 114 keV transition in175Lu

Measurements of the conversion line intensities, the directional correlation and the conversion probability for the 114 keVM1+E2 transition in175Lu are reported. TheE2 admixture, determined from relativeK andL intensities, is (19.2±0.2)%. The theoreticalLI internal conversion coefficient is found to be about 8% too low relative theK,LII andLIII conversion coefficients.

The decay of 191Au and the level scheme of 191Pt

Abstract A total of 84 transitions in 191 Pt have been established by studying the internal conversion spectrum following the decay of 191 Au with high-resolution, magnetic, beta spectrometers. Multipolarities and mixing ratios for the strongest transitions have been deduced from K/L ratios and/or L subshell ratios. The high accuracy of the transition energy determinations together with calculated total transition intensities, established multipolarities and information from coincidence experiments enabled the construction of a consistent level scheme comprising 25 excited levels and 69 transitions. This level scheme deviates greatly from that proposed by Marklund et al. 5 ).

Relative internal conversion electron intensities of the 113 keV transition in 177 Hf

The intensities of the internal conversion lines of the 113 keVM1 +E2 transition in177Hf have been measured. From comparison with theoretical conversion coefficients the transition has been found to be (95.2 ± 0.5)%E2 corresponding to ¦δ¦=4.5 ± 0.3. The theoreticalLI andMI conversion coefficients used in the comparison have been increased by 5% according to the result that for pureE2 transitions in the deformed region theLI/LII,LI/LIII,MI/MII, andMI/MIII theoretical ratios are too low (∼5%). Moreover, the present result indicates that theLII/LIII andMII/MIII ratios obtained from the tabulations by Hager and Seltzer and from the computer program by Pauli are too high (1–2%).