During the last decades there has been a substantial effort to obtain information about the region around the neutron-rich $^{132}$Sn, the most exotic doubly-magic nucleus presently at reach. The isotope $^{132}$Sn is itself a very interesting case. The simplest excited levels correspond to particle-hole states where a particle is excited across the energy gap of the neutron or proton closed...
The Recoil Distance Doppler-Shift (RDDS) technique [1] has become a well established method of measuring the lifetimes of excited nuclear states. A two-foil plunger allows excited nuclei to radiate either one of two velocities. This results in two $\gamma$-ray energies associated with each transition due to the Doppler shift in energy. The relative intensity of each of these components can...
The information on how the nuclear structure effects the beta-decay or charge-exchange reactions is most conveniently expressed by a strength function. The beta-decay probability is proportional to the product of the lepton part described by the Fermi function and the nucleon part described by beta-decay strength function. Beta-decay strength function reflects the distribution of the squared...
The spectroscopic quadrupole moment of the first excited 2$^{+}_{1}$ state, $Q_{_S}(2^{+}_{1})$, at 1.633 MeV in $^{20}$Ne has been determined from reorientation effect Coulomb-excitation measurements at safe energies using the {\small AFRODITE} array at iThemba LABS. A diagonal matrix element of $\langle 2^+_1\mid\mid \hat{E2} \mid\mid 2^+_1\rangle=-0.34(5)$ eb yields a large value
of...
The nuclear dipole polarizability is mainly governed by the dynamics of the giant dipole resonance and, assuming validity of the brink-Axel hypothesis, has been investigated along with the effects of the low-energy enhancement of the photon strength function for nuclides in medium- and heavy-mass nuclei. Cubic-spline fits to both data sets extrapolated down to a gamma-ray energy of 0.1 MeV...
The nucleus 82Sr lies in a transitional region of the nuclear landscape, between N=50 spherical nuclei and the highly-deformed N≤ 40 region. The ratio of B(E2; 4+ →2+) ⁄ B(E2; 2+ →0+) deviates heavily from systematics at 82Sr which could indicate additional physics at relatively low excitation energy. Shape effects in 82Sr have been investigated through the safe multi-step Coulomb excitation...
Multiferroic materials have been under the spotlight due to their fundamental scientific interest and for potential applications in technology. Among these interesting materials are the group of compounds belonging to the Pyroxene family with general chemical formula AM(Si,Ge)2O6. More specifically, SrMnGe2O6, SrCoGe2O6 and CaMnGe2O6 are isostructural, crystallizing with monoclinic C2/c...
There are indications that the measured number of antineutrinos emerging from reactor fission fragments inside a reactor is lower than theoretically predicted. Moreover, there is an additional anomaly in the energy spectrum of the antineutrinos. These observations are the reactor neutrino anomaly. One of the uncertainties in the theoretical description is the QCD influence on the β-decay of...
Collinear laser spectroscopy (CLS) is a high-precision technique to study the hyperfine structure (HFS) of atoms and ions [1]. The hyperfine constants are observables that contain atomic and nuclear information simultaneously. While the atomic part is independent of the neutron-number in isotopes of the same element, the contribution of the nuclear part is different due to the different...
Photoluminescence (PL) is an optical, non-destructive technique that is often used to characterize the defects in semiconductors. However, the proper chemical identification for the origin of signals can be misleading. Implanting samples with radioactive probes at ISOLDE allows for a clear chemical classification of a peak in a PL spectrum as its intensity changes with time. In this work we...
Atomic masses provide direct insights on key nuclear structure phenomena, such as shell effects or onsets of deformation, and the way they evolve far from stability. In the field of astrophysics, the masses of exotic species constitute one of the most critical nuclear physics inputs in nucleosynthesis calculations.
The ISOLTRAP, located at the radioactive ion-beam facility ISOLDE/CERN [1],...
Recently, the single-layer two-dimensional (2D) of MoS$_{2}$ is an important transition metal dichalcogenides (TMDs) compound which has been investigated [1,2]. Similar to the graphene, the monolayer of MoS$_{2}$ is used in a wide range of application including field-effect transistors, photodetectors, solar cells, chemical sensors and supercapacitors electrodes [3,4]. Furthermore, due to the...
A new hybrid medical imaging modality with promising benefits for in vivo studies has been under development since 2017 by the CERN-UCM-UNIGE and HEdS-Geneva collaboration. With this technique, called gammaMRI, we are aiming to combine the high spatial resolution of MRI (~1 mm) while increasing the sensitivity of the technique using radioactive tracers as contrast agents, as performed...
A unique feature of thorium-229 is its isomer with an exceptionally low excitation energy, proposed as a candidate for future optical clocks [1]. The small decay width is expected to outperform the accuracy of current state-of-the-art atomic clocks by an order of magnitude [2]. The current best measurement of the excitation energy results in a value of 8.28(17)eV [3], whereby the isomer is...
“New physics” beyond the standard model, such as supersymmetric models, can imply violations of discrete symmetries, i.e. space parity (P), time-reversal (T) and charge conjugation (C). Many different hypothetical sources of simultaneous violation of P- and T-symmetry can be discussed on the elementary particle level, such as P,T-odd currents between quarks and electrons or permanent electric...
The β-detected NMR technique is a well-described nuclear spectroscopy technique known to give signals with up to ten orders of magnitude more sensitive than conventional NMR. This is achieved by combining the hyperpolarization of the radioactive nuclear spins with lasers and the detection of the emitted beta particles. An additional advantage of the β-NMR is the ability to perform the...
For certain combination of protons and neutrons an appearance of reflection asymmetry is expected. In particular, the experimentally determined E3 strengths as a function of the neutron number are peaked around N~88 and N~134. Many theoretical approaches have been applied to describe the regions of enhanced octupole collectivity and its experimental signatures, such as parity doublets in...
In order to support the design of the first phase of ISOL@MYRRHA, which will operate with 100-MeV protons at intensities up to 500 µA, SCK•CEN is currently developing offline facilities, including a thermal test stand and an ISOL system coupled to a laser laboratory. The aim is to develop a Target Ion Source Assembly, targets and ion sources that can properly use the aforementioned proton...
Neutron-deficient Hg nuclei have been the subject of intensive experimental and theoretical research since the 1970s. Actually, the first direct evidence for shape coexistence near the Z=82 shell closure was obtained for neutron-deficient mercury isotopes by means of isotope shift measurements [1]. These measurements showed that there is a unique staggering in the variations of the mean-square...