Figure 1

RDDS spectra of two transitions in the yrast positive-parity band of ${}^{155}$Dy obtained by setting a gate on the shifted component of the directly feeding transitions in rings 0, 1, 5, and 6. The distances and the detector rings of observation are also indicated. The unshifted (U) and shifted (S) components are clearly distinguished.Reuse & Permissions

Figure 2

DSAM spectra of transitions in the yrast positive-parity band (Band 6) of ${}^{155}$Dy obtained by setting a gate on the full line shape of the transitions lying below the levels of interest. The gates ($\gamma$-ray energies in keV) and the detector rings of observation are also indicated.Reuse & Permissions

Figure 3

Example of lifetime determination for the 25/2${}^{+}$ level in band 6 of ${}^{155}$Dy using the gated spectra measured with the detectors at 34.6${}^{\circ }$. The gate is set on the shifted component of the directly feeding 544-keV transition. The left part of the figure presents fits of the line shape of the 464-keV $\gamma$-ray transtion at different distances. The solid black line is the full fit. In addition, the fractions of the line shape related to the unshifted peak (dashed green line) and DSA effects (dotted red line) are shown. The right part of the figure illustrates the lifetime determination according to Eq. (1). On top, the $\tau$ curve derived is displayed together with a fit with a horizontal line within the region of sensitivity. The uncertainties of the latter are also shown. See also text.Reuse & Permissions

Figure 4

Line-shape analysis of the 785-keV transition in band 6 and determination of the lifetime of the $I^{\pi }$ $=$ 49/2${}^{+}$ level at 5238 keV according to the DDCM [cf. Eq. (4)]. On the left-hand side are shown fits of the line shapes measured at the angles of 35${}^{\circ }$, 59${}^{\circ }$, 121${}^{\circ }$, and 145${}^{\circ }$ with respect to the beam axis. Dashed lines show the background as well as small contaminant peaks. The decay functions derived from the fits displayed in the left part are presented in the middle with their statistical uncertainties. The decay function of the feeding transition of 829 keV is also shown as determined from independent fits at the four detector angles. Its area is normalized to that of the decay function of the 785-keV transition. The $\tau$ curves and their statistical uncertainties calculated with the decay functions shown in the middle of the figure are presented on the right-hand side. The lifetimes ${\tau }_{\theta }$ derived at the four detector angles and their statistical errors are also displayed. The final adopted value of the lifetime is $\langle \tau \rangle =229\pm 41$ fs.Reuse & Permissions

Figure 5

The same as in Fig. 3 but for the 221-keV transition in band 2 which depopulates the 15/2${}^{-}$ level. The gated spectra are measured with the detectors at 120.6${}^{\circ }$.Reuse & Permissions

Figure 6

Line-shape analysis of transitions in Band 6 at 35${}^{\circ }$ and 145${}^{\circ }$ according to the procedure outlined in Sec. 3b. Dashed lines show the background as well as contaminant peaks.Reuse & Permissions

Figure 7

Comparison of the experimental and calculated within the PTRM level schemes of ${}^{155}$Dy. The numbers close to the arrows of the $\Delta I=2$ transitions are the $B\left(E2\right)$ values in units $e^2{b}^2$. The theoretical $\Delta I=1$ transitions in the 3/2${}^{-}$[521] and 11/2${}^{-}$[505] bands are characterized by the $B\left(E2\right)$ value in the same units (top) and the $B\left(M1\right)$ value in units of ${\mu }_N^2$ (bottom). The reduced transition probabilities of the $E1$ transitions are given in $e^{2}b$. See also text.Reuse & Permissions

Figure 8

Reduced $B(E2,I\to I-2)$ transition strengths in band 8. The results of the RDDS measurements as well as earlier data [5] are presented together with calculations within the rigid-rotor model [Eq. (9)] with the indicated parameters and the PTRM predictions.Reuse & Permissions

Figure 9

Top: Reduced $B(E2,I\to I-2)$ transition strengths in bands 1 and 2. The experimental data are compared to the PTRM calculations and the rigid-rotor model [Eq. (9)] with the indicated parameters. Bottom: Experimental $B\left(M1\right)$ values in bands 1 and 2 compared to the results of the PTRM calculations.Reuse & Permissions

Figure 10

Reduced $B\left(E2\right)$ transition strengths in band 6. The results of the RDDS and DSAM measurements are presented together with calculations within the rigid-rotor model [Eq. (9)] with the indicated parameters. See also text.Reuse & Permissions

Figure 11

Reduced $B\left(E2\right)$ transition strengths in band 7 from the present work. A calculation within the rigid-rotor model [Eq. (9)] is also displayed. The line connecting the experimental points just guides the eye. The insert shows the dependence of the alignment of band 7 on the rotational frequency. The box in the insert corresponds to the data for the levels with spins $I^{\pi }=53/2^{-}$, 57/2${}^{-}$, and 61/2${}^{-}$. See also text.Reuse & Permissions