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In superdeformed, heavy nuclei at low spins, M1 transitions enhanced by internal conversion are expected to compete favorably with E2 rays. For strongly coupled bands with fairly large B(M1) values, the decay may proceed between the two signature partner bands with very few rays emitted. Measured E2 ray intensities may imply strict limits on the M1 strength. Experimental evidence for the M1 cross
The experimental hindrance factors determined from the fine structure in the C14 decay of Ra223 are strikingly similar to the hindrance factors observed in the alpha decay of odd-A reflection-asymmetric deformed nuclei in spite of the deformed to spherical shape which occurs in the C14 decay. Calculations of the overlap between the reflection-asymmetric ground state of Ra223 and the spherical shel
Excitation energies and branching ratios in 125Xe have been correctly described by using the triaxial rotor plus particle model with deformation parameter ε{lunate}=0.25 and γ=24°. The observed properties, in particular the degeneracy of the yrast favoured and unfavored bands and the signature inversion in the yrare bands are well described by the model. The distribution of core states in the wave
It is shown that the observed transition energies in the superdeformed bands of 148Gd and 146Gd and the two bands of 147Gd are related by a simple linear expression. This is another indication of the remarkable stability of the superdeformed bands and strongly suggests that only two orbitals are active. The relative properties are analysed in terms of the (effective) aligned spin brought in by spe
The yrast band of118Xe has been extended up to tentatively Iπ = 34+ in a heavy-ion in-beam γ-spectroscopic study using the NORDBALL detector array. A band crossing is observed at the highest spins and interpreted within the Modified Oscillator Model as a transition to a terminating band.
We reply to the preceding Comment.
Detailed spectroscopic studies of the discrete γ-rays feeding and deexciting a 41 2-, 4.6 MeV level in 191Hg are reported. The resulting decay scheme indicates single-particle nature for the states above the 41 2- level. At moderate spin, the corresponding particle alignment mode competes favorably with collective oblate rotation. It is suggested that this sequence is associated with a non-collect
We discuss how especially the alignment and the shape polarisation of specific orbitals influence the transition energies in superdeformed bands. The very similar transition energies observed recently in neighbouring nuclei can be qualitatively understood in our approach and the special properties of high-N orbits can be analysed in the same formalism.
Lifetime measurements for the isotopes 155Dy and 156Dy have been extended up to spins around 40h{stroke} by the Doppler shift attenuation method in conjunction with γ-γ-coincidence measurements. Results have been obtained for the yrast band in 156Dy and for three bands in 155Dy. Strong retardations of the E2-strengt were observed for intruding terminating sequences, for which specific single parti
The reanalysis of all the experimental data on 225Ra demonstrates the coexistence of reflection asymmetry and reflection symmetry in this nucleus. In 225Ra as well as 227Ra and 229Th this phenomenon can be explained by the calculated ability of the odd particle in different orbitals to polarise the soft nuclear shapes toward smaller and larger octupole deformations.
The special degeneracy which occurs in the harmonic-oscillator potential when two of the frequencies have ratios of small integer numbers is exploited. Favored shell energies occur for particle numbers which vary with the third frequency. Applications to realistic nuclear potentials show that this degeneracy leads to special shell effects for axial shapes (1:1 ratio) but also for the 2:1 ratio exe
Low-temperature nuclear orientation experiments with isotope separated 228,230pa in an iron host matrix have been performed. From the temperature dependence of the γ-anisotropy in the decay of the isotopes the Larmor frequencies of the ground states have been derived as |VL(228PaFe)| = 552(17) MHz and |vL(230PaFe)| = 475 (13) MHz. Using Bhf(PaFe) = -62.8 (9.0) T the magnetic moments have been dedu
Conventional radio-frequency acceleration form the basis of most accelerators in industry today, and is a scaleable technology used in large-scale research laboratories all over the world. The final particle energy and the availability of the devices are, however, often limited by practical concerns such as price, size, and energy consumption. This prompts research into alternative acceleration me
Multiple superdeformed rotational bands have been identified in a nucleus for the first time. Cascades of 14, 13, and 11 transitions have been assigned to three bands in Dy153. Despite the small intensities, it has been possible to follow the decay of these bands from an angular frequency of 0.7 down to 0.4 MeV/Latin small letter h with stroke. In all three cases, the dynamic moment of inertia scr
The particle-rotor model using strong coupling basis functions is briefly reviewed. Recent developments are discussed. For example, a formalism for odd-odd nuclei (and negative parity states in even nuclei) is presented. With a standard neutron-proton interaction, measured spins and moments of transitional and deformed Ho nuclei are used to extract their main configurations. Total energy calculati
New high spin states in Mg25 (up to 13.3 MeV in excitation) have been located using the N12,p)25Mg reaction at a laboratory beam energy of 23.5 MeV. Gamma decay from 28 neutron unbound levels has been observed (24 of which are reported here for the first time) up to 7 MeV above the neutron drip line. Tentative identification of the yrast line up to (17/2+ has been made, along with an extension of
High-spin states in 154Dy have been studied using the TESSA2 γ-rays spectrometer following the 110Pd(48Ca,4n)154Dy reaction at a beam energy of 210 MeV. States up to 44+ and 37- have been observed. Below spin 30 the data display regular rotational behaviour which can be interpreted in terms of the cranked shell model. Above spin 30, sequences of levels connected by stretched E2 transitions, which
Six rotational bands up to energies Ex = 24.7 MeV and spins Jπ=(79/2−) have been identified in 109Sn using the GAMMASPHERE γ-detector array. Four of the bands show smoothly decreasing dynamic moments of inertia at rotational frequencies ℏω > 0.6 MeV. The bands arise at medium spins from a coupling of a valence d5/2, g7/2 or h11/2 neutron to the deformed 2p2h proton excitation of the Z=50 core 108S
The moments of inertia of rotational bands in the cranked harmonic oscillator are explored. The important role played by the maximum spin is pointed out. A qualitative agreement is found with the properties of recently observed superdeformed bands.
New high spin states in 25Mg have been located above the neutron threshold using the 12C(14N, pγ)25Mg reaction at E=23.5 MeV. The members of the ground state rotational band (Kπ= 5 2+ have been tentatively identified up to 15 2+. The yrast 15 2+ (not a member of the ground state band) and 17 2+ states have also been tentatively assigned. These results support the interpretation of the new 17 2+ st
