Figure 1

$\beta$-gated $\gamma$ spectrum recorded at mass 80 in the 0–1800 keV energy range.Reuse & Permissions

Figure 2

Relative $\gamma$ intensities for transitions in ${}^{80}$Ge observed in this experiment (vertical axis) vs. relative $\gamma$ intensities from the evaluation [6] (horizontal axis). Symbols are in red (above diagonal) or green (below diagonal) for $\gamma$ activity in clear (more than $2\sigma$) excess or deficit, respectively, of the ${}^{80a+80b}$Ga source obtained in the present experiment from photofission of ${}^{238}$U with respect to the compiled values. The last ones originate from the ${}^{235}$U thermal neutron induced fission data of Ref. [5]. Lines are drawn only to guide the eye. Numbers close to the symbols correspond to the excitation energy, in keV, of the ${}^{80}$Ge states from which the $\gamma$-emission originates.Reuse & Permissions

Figure 3

Measured apparent half-life of the levels of ${}^{80}$Ge (squares) and transitions not placed in the level scheme (circles). The adopted value $T_{1/2}=1.676$ s [6] is represented by the dashed line.Reuse & Permissions

Figure 4

$X$, the fraction of the feeding to ${}^{80}$Ge states from the lower-spin ${}^{80}$Ge isomer, as given by Eq. (2), sorted as a function of the energy level in ${}^{80}$Ge on the ordinate axis.Reuse & Permissions

Figure 5

Proposed decay schemes for the two ${}^{80}$Ga $\beta$-decaying states following the discussion of Sec. 4, up to 3600 keV excitation energy. On the left hand side are displayed the levels fed directly by the $\beta$ decay of the longer-lived isomer ($J=6$), on the right hand side those fed directly by the $\beta$ decay of the shorter-lived isomer ($J=3$). Transitions displayed in the middle are those connecting the two decay schemes.Reuse & Permissions

Figure 6

The ${}^{80}$Ge experimental level scheme placed in the Ge (left-hand part) and $N=48$ (right-hand part) systematics. $J^{\pi }$ assignments for ${}^{80}$Ge proposed in Sec. 5c are accompanied by a star, the others are taken from previous works and evaluations, as quoted elsewhere in this paper. Only the energy of the $8^{+}$ state in ${}^{76}$Ge is taken from an unpublished work [36].Reuse & Permissions

Figure 7

Central part: ${}^{80}$Ge experimental levels (up to 5 MeV). Those attributed to the higher-spin $\beta$-decay scheme are shifted to the left and those attributed to the lower-spin $\beta$-decay scheme to the right. Unless specified, the former are proposed $(J\ge 4)$ and the latter $(1\le J\le 3)$ according to the discussion of Sec. 4. $J^{\pi }$ adopted by the evaluator are reported when available, those which are proposed after the discussion of Sec. 5c are accompanied by a star. Levels with uncertain decay-scheme assignment (3914 and 4026 keV in this energy span) are left in the middle. On the left (right) side is displayed the calculated level scheme using JUN45 (JJ4B) residual interaction, sorted in band-like structures according to their major $E2$ connections. Numbers close to the transition arrows are the $B\left(E2\right)$ values in $e^2{\mathrm{fm}}^4$. Apart from the $2_2^{+}\to 0_1^{+}$ transitions, only $E2$ transitions with $B\left(E2\right)>50$$e^2{\mathrm{fm}}^4$ are reported here for the sake of clarity.Reuse & Permissions

Figure 8

Centroids of the intrinsic deformation parameters ${\beta }_s$ and ${\gamma }_s$ in polar representation for states $s=0_{1-3}^{+},2_{1-3}^{+},3_1^{+},4_{1-3}^{+},5_1^{+},6_{1,2}^{+},8_1^{+}$ in ${}^{80}$Ge. Values correspond to the shell model wave-functions obtained using the (a) JUN45 and (b) JJ4B sets of residual interaction parameters, through the evaluation of the Kumar operators with $E2$ matrix elements (see text). States which are $\gamma$-soft according to the value of the width $\sigma \left(\cos 3\gamma \right)$ as defined by Eq. (11) in Ref. [27] are marked with thin double arrows. The main $E2$ transitions connecting the states are represented by thick black arrows.Reuse & Permissions

Figure 9

Proton configuration distribution of the wave-functions of the $0_{\mathrm{g}.\mathrm{s}.}^{+},2_{1,2}^{+},3_1^{+},4_{1,2}^{+},6_{1,2}^{+}$ states in ${}^{82}$Ge (top) and ${}^{80}$Ge (bottom). The value of a given component of the wave function, in percent, is represented with plain color (black and gray) bars for shell model results obtained with the JUN45 interaction and hatched (doubly and simply) bars for those obtained with the JJ4B interaction. Only the five leading components are represented here: configuration $1=\pi f_{5/2}^4$, configuration $2=\pi \left(f_{5/2}^2{p}_{3/2}^2\right)$, configuration $3=\pi \left(f_{5/2}^3{p}_{3/2}^1\right)$, configuration $4=\pi \left(f_{5/2}^2{p}_{3/2}^1{p}_{1/2}^1\right)$, and configuration $5=\pi \left(f_{5/2}^3{p}_{1/2}^1\right)$ as illustrated schematically in the uppermost part of the figure. For ${}^{80}$Ge, the fraction of a given proton configuration coupled to a simple two hole $\nu g_{9/2}^{-2}$ configuration is represented with full black bars and gray bars on top of the previous when the hole pair is promoted to the deeper neutron orbits $\nu p_{1/2}^{-2},p_{3/2}^{-2},f_{5/2}^{-2}$, for JUN45 calculation results. The equivalent is crossed-hatched and simply hatched respectively for JJ4B results.Reuse & Permissions