Excited states in 133 Sn were investigated through the β decay of 133 In at the ISOLDE facility. The ISOLDE Resonance Ionization Laser Ion Source (RILIS) provided isomer-selective ionization for 133 In, allowing us to study separately, and in detail, the β-decay branch of 133 In J π = (9/2 +) ground state and its J π = (1/2 −) isomer.

There is sparse direct experimental evidence that atomic nuclei can exhibit stable 'pear' shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole (E3) matrix elements have been determined for transitions in 222,228 Ra nuclei using the method of sub-barrier, multi-step Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of E3 matrix elements for different nuclear transitions is explained by describing 222 Ra as pear-shaped with stable octupole deformation, while 228 Ra behaves like an octupole vibrator.

There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we observed the low-lying quantum states in 224Rn and 226Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment.

Background: Shell evolution can impact the structure of the nuclei and lead to effects such as shape coexistence. The nuclei around 68 Ni represent an excellent study case, however, spectroscopic information of the neutron-rich, Z < 28 nuclei is limited. Purpose: The goal is to measure γ-ray transitions in 66 Fe, 66 Co, and 66 Ni populated in the β − decay of 66 Mn to determine absolute β feedings and relative γ-decay probabilities and to compare the results with Monte Carlo shell model calculations in order to study the influence of the relevant single neutron and proton orbital occupancies around Z = 28 and N = 40. Method: The low-energy structures of 65,66 Fe, 66 Co, and 66 Ni were studied in the β − decay of 66 Mn produced at ISOLDE, CERN. The beam was purified by means of laser resonance ionization and mass separation. The β and γ events detected by three plastic scintillators and two MiniBall cluster germanium detectors, respectively, were correlated in time to build the low-energy excitation schemes and to determine the β-decay half-lives of the nuclei. Results: The relative small β-decay ground state feeding of 66 Fe obtained in this work is at variant to the earlier studies. Spin and parity 1 + was assigned to the 66 Co ground state based on the strong ground-state feeding in the decay of 66 Fe as well as in the decay of 66 Co. Experimental log(f t) values, γ-ray de-excitation patterns, and energies of excited states were compared to Monte Carlo shell model calculations. Based on this comparison, spin and parity assignments for the selected number of low-lying states in the 66 Mn to 66 Ni chain were proposed. Conclusions: The β-decay chain starting 66 Mn toward 66 Ni, crossing N = 40, evolves from deformed nuclei to sphericity. The β-decay population of a selected number of 0 + and 2 + states in 66 Ni, which is understood within shape coexistence framework of Monte Carlo shell model calculations, reveals the crucial role of the neutron 0g 9/2 shell and proton excitations across the Z = 28 gap.

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