The study of nuclear fission remains a critical area of research, not only for understanding fundamental nuclear properties but also for its implications in the production of heavy elements in astrophysical environments. In r-process nucleosynthesis, fission plays a crucial role as it ultimately limits the mass of nuclei that can be produced. Currently, very limited data on fission barriers of...
The evolution of nuclear collectivity and structure in the region surrounding the doubly-magic nucleus $^{132}$Sn remains a central open question in nuclear structure physics. Recent shell-model calculations, employing realistic interactions, predict an enhancement of collectivity in the neighboring even-even isotopes of $^{132}$Sn [1]. Despite this, a long-standing discrepancy between...
The $\alpha$-nuclear potential in exotic nuclei, a key input in modeling the astrophysical p-process [1,2], remains a source of uncertainty due to the lack of experimental data. This potential can be constrained experimentally by measuring the differential cross-section of $\alpha$-scattering near the Coulomb barrier and identifying the best-fit interaction model.
In the context of...
The ISOLDE Long Shutdown starts at the end of December and will last two years to accomodate the replacement of the ISOLDE dumps as well as the upgrade of the BTY line for 2GeV proton beam, the refurbishement of HIE ISOLDE Cryo Module 1 and many other improvements, consolidation and maintenance to the facility and the experimental setups.
This talk will give you an overview and timeline of...
The ISOLTRAP mass spectrometer [1], located at ISOLDE/CERN, performs high-precision mass measurements of short-lived, exotic nuclides far from stability. These measurements provide direct access to nuclear binding energies, which reflect the underlying nuclear interactions, thereby enabling studies in nuclear structure and nuclear astrophysics, among others.
For this, the ISOLTRAP mass...
Recent Monte Carlo Shell Model (MCSM) calculations made by T. Togashi et. al. [Phys. Rev. Lett. 121, 062501 (2018)] attempt to account for discrepancies observed between measurements and previous theoretical calculations of the reduced transition probability B(E2;$2^{+}_{1}->0^{+}_{1}$) in the neutron deficient Sn isotopes. One of the predictions of the MCSM calculation is that a shape change...
Anaïs Lépine on behalf of the WISArD collaboration
The Standard Model (SM) has proven to be a successful theory describing three of the four fundamental interactions. However, some open questions remain and motivate precise measurements to search for evidence of physics Beyond the SM predictions. For instance, the measurement of the shape of the β energy spectrum can be used to search for...
Laser resonance ionization spectroscopy in the ion source coupled directly to the isotope
production target has been proven to be a highly sensitive tool for nuclear structure investigations on
isotopes with low production and extraction yields [1]. While the efficiency of this technique is
unrivalled, the spectral resolution is ultimately limited by Doppler broadening. At the ion source...
The JYFL Accelerator Laboratory (JYFL-ACCLAB) is one of the leading stable beam facilities in Europe, conducting world class research on basic natural phenomena. Presently the laboratory hosts four accelerators with a variety of ion sources and innovative instrumentation for fundamental research, ion-beam based materials physics and applications. The current main research facilities includes...
The MIRACLS collaboration at CERN–ISOLDE has developed a novel experimental platform that combines ion-bunch confinement in a multi-reflection time-of-flight (MR-ToF) device with high-resolution collinear laser spectroscopy (CLS). When ions are bouncing back and forth between between the two electrostatic mirrors of the MR-ToF device, the ion-laser interaction time is dramatically increased...
Recent Total Absorption Spectroscopy (TAS) experiments at the ISOLDE have provided new nuclear data with implications spanning from nuclear astrophysics to medical applications.
In the astrophysical domain, the beta+/EC decay of the waiting-point nucleus 64Ge has been measured with the Lucrecia TAS setup. The resulting B(GT) distribution has been compared with theoretical calculations...
To explain the significant baryon asymmetry observed in the universe, a larger source of charge and parity (CP) violation is required [1]. Signatures of such CP-odd properties could be observed as small shifts in the transition frequencies of atoms and molecules [2,3]. Particularly, molecules have become the current most sensitive approach for CP-violation studies due to their strong internal...
Terbium-149 has been regarded as an attractive candidate for Targeted Alpha Therapy (TAT) since the 1990's [1], due to its favourable physical decay properties (T1/2 = 4.1 h, Eα = 3.97 MeV, 17%; Eβ+mean = 720 keV, 7%) [2]. Preclinical studies have demonstrated its therapeutic potential [3-6], as well as its potential for therapy monitoring via positron emission tomography (PET) [4]. The...
With its unique combination of an external magnetic field of up to 8.5 Tesla and the ability to heat and cool samples during measurements, the MULTIPAC Time-Differential Perturbed Angular Correlation (TDPAC) setup creates new possibilities for studying materials and their phase transitions. Building on this advanced instrumentation, the dedicated control and analysis software PACBit enables...
CERN-MEDICIS aims at producing and purifying by mass separation non-conventional radionuclides for research and development in diagnostics and radiation therapy.
It triggered PRISMAP and PRISMAP+ EU projects – furthering the European medical radionuclides programme, supporting the ongoing research across Europe and beyond in radiopharmaceutics.
CERN-MEDICIS exploits in a dedicated...
Safety is a core value at CERN and at the ISOLDE facility. This talk will outline how safety is managed within this framework and clarify the distinct roles of the different involved Safety Officers. It will also explain the Safety Incident Management process existing at CERN, including the definition of incident and the available tools. Using examples from past incidents at ISOLDE, the...
Remarkable advances have been made in recent years with the theoretical description of electromagnetic properties of atomic nuclei, stimulated by a wealth of high-quality experimental data on short-lived radionuclides (see references [1-6]). In this context, nuclear charge radii are highly rewarding observables which serve as a sensitive probe of phenomena such as pairing, deformation, or...
L. Acosta(1), R. Berjillos(2), I. Bustinduy(4), J. Correa-Laorden(1), Y. Fontenla(3), C. García-Ramos(2), J. Giner-Navarro(3), D. Gómez-Domínguez(2), Carlos A. Gonzalez(2), G. Kirby(2), T. Kurtukian-Nieto(1), I. Martel(2), J. L. Muñoz(4), A. Perea(1), J. Resta-Lopez(3), S. Sanchez-Navas(1), F. Taft(3), F. Torabi(2),for the ISRS collaboration(5)
1 IEM-CSIC, 28006 Madrid, Spain
2 University...
This talk explores the latest advancements in power supply technologies designed by CAEN: it will give a quick overview of the EASY power supply system for the High-Luminosity Large Hadron Collider (HL-LHC) upgrades: notable for its enhanced radiation tolerance: up to 150 Gy, 3x10^11 HeH/cmq, 1.5x10^12 Neq/cmq, and resilience to magnetic fields up to 0.6 T.
Furthermore, we will also discuss...
The WISArD experiment aims to probe possible manifestations of new physics in the weak interaction sector of the Standard Model through precision studies of beta decay. In particular, the experiment targets the angular correlation parameter a and the Fierz interference term b, which are sensitive to exotic scalar and tensor currents beyond the vector and axial-vector interactions of the...
By introducing spin polarisation into β-decay studies, one can overcome the difficulty of conventional β-decay spectroscopy to firmly determine the spins and parities of nuclear states involved in allowed transitions. This is because the sign and degree of asymmetry in β-decay from polarised nuclei depends on the spin difference between the initial and final states.
This novel approach to ...
Helium-3 gas-filled proportional counters are extensively used as neutron detectors for measurements in a wide range of applications. A recent example are ($\alpha$,n) reactions measured by the MANY collaboration using the miniBELEN detector [1]. This kind of neutron counters are also commonplace as neutron monitors, both for the study of cosmic rays and solar weather [2], as well as...
Regions near closed shells in areas of the nuclear chart far from stability are very interesting from the point of view of nuclear structure, since a shell model description based on single-particle states can be challenged by collective effects. One of the most interesting regions is the one around the doubly-magic $^{78}$Ni nucleus, with $Z=28$ and $N=50$ [1].
The systematics of...
The Apparatus for Surface Physics and Interfaces at CERN (ASPIC) was previously installed in the solid-state physics section of the ISOLDE experimental hall, where it operated under ultra-high vacuum conditions (UHV, $\leq 10^{-8}$ mbar). ASPIC enabled studies of metallic surfaces, magnetic thin films, and interface dynamics, and supported experiments using radioactive isotopes and a range of...
Exploring ground-state nuclear properties is a powerful tool to investigate our understanding of nuclear structure. Laser spectroscopy gives access to nuclear ground-state properties, such as the nuclear spin, electromagnetic moments and changes in the mean-squared charge radius of short-lived ($\geq$10 ms) nuclei by measuring the hyperfine $A$-and $B$-parameters and isotope shift [1]....
$^{225}$Ac has been identified as a promising isotope for Targeted Alpha Therapy (TAT) treatment of metastasized tumors [1]. For logistic and medical purposes, a better understanding of the nuclear data along the entire $^{225}$Ac decay chain is required. Currently discrepancies are observed when measuring the activity using techniques that utilize different daughter nuclides and different...
The IS685 experiment studies exotic, neutron-rich In isotopes populated in the Cd $\beta$ decay using high-resolution $\gamma$-ray spectroscopy and fast-timing techniques~[1]. Understanding nuclear structure in this region requires the systematic investigation of nuclei around the double $Z=50$ and $N=82$ shell closure, where collective effects set in with only few extra nucleons. Exotic...
The $RbNdNb_{2}O_{7}$ (RNNO) and $CsNdNb_2O_7$ (CNNO) systems exhibit a sequence of phase transitions before reaching their hig temperature $P4/mmm$ aristotype phase. In RNNO, the structure evolves from a polar $I2cm$ phase at room temperature to an antipolar $Cmca$ phase at $790\,K$, and finally to a distorted $I4/mcm$ structure at $865\,K$ [1]. These transitions arise from rotations and...
The beta decay of 8He was measured at IDS in 2022. 16% of decays populate excited states in 8Li which decay by neutron emission and alpha-neutron-triton breakup. Due to significant background the double alpha breakup of 8Be following the beta decay of 8Li, a triple coincidence must be made to identify alpha-neutron-triton events. Owing to the complexity of detecting neutrons, the response and...
The ISOLDE Superconducting Recoil Separator (ISRS)[1] under development at CERN aims to achieve unprecedented mass resolution and transmission efficiency through a compact, Fixed Field Alternating Gradient (FFAG) storage ring composed of Canted Cosine Theta (CCT) multifunction superconducting magnets. Each MAGDEM prototype integrates combined dipole and quadrupole fields within a cryogen-free...
The ISOLDE Superconducting Linear Spectrometer (ILS) [1] marks the start of the operational phase of the ISOLDE Superconducting Recoil Separator (ISRS) [2-3] project. Designed as the first operational stage of ISRS, the ILS provides a compact experimental platform to test the key superconducting magnet and beam optics technologies that will be implemented in the full separator. The system,...
Over the past several years, extensive studies have been devoted to the structure of neutron-rich tin isotopes, which possess a closed proton shell, with ¹³²Sn being a doubly magic nucleus. For this reason, these nuclei play a particularly important role in testing the validity of the nuclear shell model and serve as a benchmark for theoretical predictions. Information obtained in this region...
The investigation of $\beta$-decay properties of neutron-rich nuclei in the A $\approx $ 120 region provides essential input for testing modern nuclear-structure models and for constraining astrophysical r-process simulations. In this context, the $\beta^-$ decay of $^{118}$Pd (Z = 46, N~=~72) populating excited states in $^{118}$Ag was studied at the Ion Guide Isotope Separator On-Line...
Resonant laser ionization is an efficient and highly selective method for producing radioisotopes. In the laser ion source of ISOLDE – RILIS (Resonance Ionization Laser Ion Source), the laser interaction region is inside a metal tube which is heated to temperatures of up to 2200 degrees Celsius. This heating induces surface ionization from the walls of this so-called “hot cavity”. If the...
A comprehensive optics model of the ISOLDE low-energy transfer lines has been developed and validated to support improved beam delivery for experiments such as PUMA. The model, implemented in MAD-X and Xsuite, incorporates survey data, apertures, and CST-validated electrostatic quadrupole fields. Benchmarking through quadrupole scans, kick-response measurements, and tomographic reconstruction...
Demands with respect to yield, purity, reliability are driving development efforts. Recent years focus on nanomaterials: release bottleneck in RIB production where nanometric size is promising for diffusion-limited isotopes. This often goes hand in hand with increase in surface area, which significantly impact effusion efficiency for open pores. Nanotechnology has been considered for...
Abstract
Octupole deformations are predicted to occur in nuclei in the region $130\leq N \leq 140$ and $85 \leq Z \leq 92$ [1]. Nuclei that exhibit octupole deformations are of interest for ongoing searches for permanent atomic electric-dipole-moments and beyond Standard Model physics.
Recent studies suggest the octupole deformed region north-east of $^{208}$Pb extends down to At...
L. F. de Almeida (∗1), A. C. Miranda (1,2), P. Rocha Rodrigues (1), N. L. Prasannan (1), J. G. Correia (2), A. Cesario (1), P. A. Sousa (1), J. M. A. Pereira (1), J. P. Araujo (1), A. M. L. Lopes (1)
1-IFIMUP and LaPMET, Department of Physics and Astronomy, Faculty of Sciences of the University of Porto, Porto, Portugal;
2-C2TN, DECN, Instituto Superior Tecnico, Lisboa,...
This work presents the engineering design and analysis of the upgraded beta-NMR end station at the VITO beamline. The upgrade was aimed at enabling studies of air-sensitive samples in a wide range of temperatures in 4.7 T magnetic field. This led to the requirements of non-magnetic materials, ultra-high vacuum, load-lock system for sample changes, and heating and cooling capability. The...
Development and testing of nanostructured uranium carbide targets for ISOLDE physics
Authors: V. Berlin$^1$, M. Au$^1$, E. Aubert$^1$, A. Boucherie$^1$, N. Conan$^1$, B. Crepieux$^1$, A. Dorsival$^1$, M.A. Grasser$^1$, L. Lambert$^1$, E. Reis$^1$$^,$$^2$, S. Rothe$^1$, S. Stegemann$^1$, J. Vollaire$^1$, S. Usta$^1$, J. Zucchi$^1$
$^1$ Center for European Nuclear Research,...
Laser spectroscopy of neutron-deficient lutetium isotopes (Z=71) can provide insights into the evolution of nuclear structure towards the proton drip line, independent of any nuclear models. Probing the hyperfine structure with laser spectroscopy allows the measurement of nuclear spins, magnetic moments, quadrupole moments and isotope shifts of these exotic nuclei. The isotope shift can then...
Silicon carbide (SiC) has historically been employed as a target material at ISOLDE (CERN) [1] and ISAC (TRIUMF) [2] and is currently under evaluation and development at emerging facilities including ISOL@MYRRHA (SCK CEN) [3] and SPES (INFN) [4]. Thanks to its high thermal conductivity, excellent emissivity, and chemical stability at elevated temperatures, SiC is under investigation for...
We present the status of the design and simulations of a future end-station at the VITO beamline aimed at performing collinear Laser-Radiofrequency (RF) Double-Resonance Spectroscopy. The future experiment is intended to significantly enhance the precision in determining the Hyperfine Structure (HFS) constants of short-lived exotic nuclei (e.g., K isotopes), with an expected reduction in...
The Resonance Ionisation Laser Ion Source (RILIS) continues to be the ion source chosen most often to provide radioactive ion beams (RIBs) for experiments at CERN-ISOLDE, as ionisation through optical resonance offers high chemical selectivity and efficiency [1,2]. To suppress potentially contaminating surface ionisation whilst maintaining laser ionisation, Laser Ion Source and Trap (LIST) was...
Uranium carbide (UCₓ), thorium carbide (ThCₓ), and lanthanum carbide (LaCₓ) constitute approximately 85% of the target materials used at CERN-ISOLDE. These carbides are highly pyrophoric and must be chemically stabilized after proton irradiation to enable their safe handling and disposal as radioactive waste, preventing ignition and thermal runaway upon exposure to ambient air or oxidizing...
Colour centres based on group-IV impurities (SiV, GeV, SnV, and PbV) in diamond are intensively investigated in the context of quantum nanophotonic applications, with some of their attractive properties stemming from the inversion symmetry of their split-vacancy configuration and their high Debye-Waller factor. In addition to inheriting the inversion symmetric properties of a split-vacancy...
The Collinear Resonance Ionization Spectroscopy (CRIS) experiment at CERN ISOLDE is used to perform hyperfine structure and isotope shift measurements [1]. The resonance ionization in collinear geometry provides selectivity over different nuclear isomeric states, which decay can be measured at the Decay Spectroscopy Station (DSS). The DSS setup has been under development over the years [2,3]...
High resolution laser spectroscopy has been used to study the atomic hyperfine structure of thulium isotopes (Z=69) leading towards the proton emitter 147Tm. This technique results in a model independent measurement of the nuclear magnetic dipole moments, electric quadrupole moments and change in mean-square charge radii, with respect to the stable 169Tm. Collinear laser spectroscopy...
The nuclear shell model, combined with pairing correlations, offers a straightforward explanation of the low-energy spectra of semi-magic nuclei. In a single high-$j$ orbital with more than two particles, low-lying $J>0$ states arise from recoupling of unpaired nucleons and group into multiplets labeled by seniority $\nu$—the number of unpaired particles. The generalized seniority scheme is...
In the past few years, spectroscopy of radioactive molecules has been performed at ISOLDE (CERN) using the Collinear Resonance Ionization Spectroscopy (CRIS) experiment [1]. Given their structure and chemical properties, radioactive molecules are promising candidates for studies in different fields [2], including for more efficient extraction of refractory elements from ISOLDE targets...
As part of the IS708 experiment carried out at ISOLDE, safe Coulomb excitation measurements with the Miniball detector were performed to investigate octupole and quadrupole collectivity in neutron rich 144Ba. The data from this experiment also provided the opportunity to study such deformation in a selection of other observed A=144 isobars including stable 144Nd, 144Sm as well as radioactive...
A new ion-implantation chamber has been commissioned at the General Low Mass (GLM) beamline of ISOLDE to improve operational efficiency and safety in handling radioactive ion beams. Replacing the former single-chamber system, the new setup features a dual-chamber load-lock design comprising an implantation chamber and a loading/unloading chamber, separated by a DN200 gate valve. Each chamber...
The main purpose of Offline 2 mass separator as part of the CERN-ISOLDE offline facilities is to perform preparatory studies and to benchmark new beam production and manipulation techniques or new beam instrumentation before their online implementation.
Similarly to GPS and HRS, the Offline 2 frontend comprises a gas mixing system to allow the introduction of reactant gases into the target...
The ISOLTRAP setup is a high-precision mass spectrometer designed to measure the masses of short-lived, exotic radionuclides far from the valley of stability. Utilizing both multi-reflection time-of-flight (MR-ToF) and Penning-trap mass spectrometry, ISOLTRAP performs precise absolute and relative mass measurements. Converting these measured masses into nuclear binding energies (via the...
Understanding nuclear structure requires precise experimental data on ground-state properties across isotopic chains. Collinear Laser Spectroscopy (CLS) provides a powerful means to determine nuclear spins, magnetic dipole and electric quadrupole moments, and changes in the mean square charge radii through measurements of hyperfine structures and isotope shifts. However, extending these...
Ab initio calculations of NMR shielding constants have made it possible to re-evaluate nuclear magnetic dipole moments from NMR experiments, offering a substantial improvement over traditional diamagnetic corrections.
In this work, we report accurate ab initio NMR shielding constants for selenium and tellurium compounds: (1) Se(CH$_3$)$_2$ and Te(CH$_3$)$_2$, which define the current NMR...
Due to the ever-increasing demands and the interconnectedness of the different machines operating at ISOLDE, a general timing system is proposed for the facility to synchronize the operation for the different sub-systems, such as the new mass separator beamline RC6, the HRS and GPS beamgates, the upcoming central beamline switching, ISCOOL, RILIS laser trigger generation, etc. The different...
The growing field of nuclear medicine theranostics relies on radionuclides that combine diagnostic and therapeutic functions [1]. Among these, the four isotopes of Terbium Tb-149, Tb-152, Tb-155, and Tb-161 offer complementary decay modes suitable for PET, SPECT, and targeted alpha and beta therapy, earning Terbium the title of the “Swiss army knife” of nuclear medicine [2,3].
To produce...
The neutron-rich lanthanides are expected to exhibit octupole collectivity, which can lead to asymmetric nuclear shapes. The study of low-lying negative-parity states in the even-even nuclei in this region is key to understanding the magnitude of collectivity and whether the nucleus adopts a static or dynamic asymmetric shape. Lifetimes of these states are particularly sensitive to...
Isotope shift measurements and the King plot are an established method to determine the nuclear charge radius [1]. Nonlinear effects in King plots have recently gained additional interest as probes for higher-order nuclear deformation and beyond-standard-model physics [2,3]. Methods like the generalized King plot allow to extract multiple effects such as higher-order nuclear deformation and...
The generalised seniority scheme is a truncated version of the nuclear shell model [1]. It is able to describe the structure of atomic nuclei in the vicinity of shell closures. The number of unpaired nucleons, the seniority $\nu$, is considered a good quantum number.
The region of the even-even Po-Rn-Ra nuclei with $N=124$ exhibits strong signs of seniority-like behaviour. This can be...
Technical poster on the future flexible ion source for COLLAPS, detailing the specific and unique requirements of an ion source for fast beam spectroscopic purposes. This source will function as a metal ion source capable of vapourising a variety of metals into atomic gasses using a fibre laser before ionising them using electron impact ionisation. This technique will also allow the source to...
The isotope $^{229}$Th is of particular interest because of its exceptionally low-energy isomeric state (8.2 eV), which can be probed via vacuum ultraviolet (VUV) spectroscopy and holds significant potential for the development of a nuclear clock [1,2]. Understanding this isomer’s properties, including its excitation and decay modes, is hereby essential and involves investigating the nuclear...
The radionuclides used in targeted radionuclide therapy emit charged particles, such as α, β- and Auger electron, that makes possible the delivery of a significant dose to the tumour cells while sparring the healthy tissues surrounding them. The radioisotope 111Ag (T1/2 = 7.45 days, Emax,β- = 1.04 MeV) is a β- emitter that is promising for this kind of application. Its low energy β- has a...
The region of the nuclear chart centred around $^{32}$Mg, known as the Island of Inversion (IOI), is characterised by the onset of deformed configurations in the ground states due to particle excitations across a weakening N=20 shell gap. The IOI has been described using numerous observables, but information regarding the single-particle structure of nuclei in this region is limited. The aim...
We report several advances in the field of ion beam development towards the study of radioactive molecules. Radioactive molecules are predicted to be powerful tools in the study of physics beyond the standard model, as they potentially enhance permanent dipole moments in the leptonic (electron electric dipole moment - eEDM) or hadronic (Nuclear Schiff moment, Magnetic Quadrupole Moment - NSM,...
Several of the most promising searches of physics beyond the standard model of particle physics are led by low-energy experiments. Typically, these searches involve atoms and the sensitivity to new physics is given by interactions involving the atomic nucleus. Therefore, the structure of these nuclei is key to interpret the experimental results. This information is usually encoded into a...
The target and ion source groups are responsible for developing the ISOLDE target and ion source units. In order to fulfill the high demand for new beams, higher beam purity and intensity, and more resistant targets, development of beams and targets is necessary. Recent developments in ISOLDE targets will be presented.
In addition, future experiments at CERN will require protons, which will...
Neutron-rich nuclei near doubly-magic 132Sn offer a valuable testing ground for exploring both nuclear structure and the astrophysical r-process. Investigation of neutron-branching ratios in this region offers benchmark testing of theoretical descriptions of neutron-rich nuclei, and the N = 82 shell closure provides an isotonic chain of waiting-point nuclei critical to r-process trajectories...
In this gamma spectroscopy analysis, we aim to measure the spectroscopic quadrupole moments of excited states and electromagnetic transition rates in neutron-deficient 140Sm. The experimental data was collected during a Coulomb excitation experiment at ISOLDE in 2017, utilizing a 140Sm beam on a 208Pb target and the Miniball HPGe array alongside a CD particle detector.
The chain of samarium...
Dynamic Nuclear Polarisation (DNP) is powerful technique for enhancing the sensitivity of Nuclear Magnectic Resonance (NMR). Originally developed in 1960s, the DNP has been deployed in nuclear polarised targets around the world for high-energy scattering experiments. In the last 20 years DNP found its way back in modern NMR spectroscopy and imagining. There are currently very few commercially...
The nuclear radius is one of the fundamental properties of the atomic nucleus. While the direct measurement is not always possible, one can infer its size by measuring other observables.
Recent theoretical studies by Bonnard and collaborators have put in evidence the role of the large radius of low-l orbits in a main nuclear shell in determining the nuclear radius and its evolution when...
Solid-state battery (SSB) technology presents a transformative alternative to conventional liquid-state batteries, addressing many of their inherent weaknesses. However, current SSB materials are limited by poor charge-discharge rates, primarily due to restricted ion diffusion and low conductivity across buried interfaces. Conventional characterization and ion diffusion measurements focus...
Here I will present our new experimental and theoretical work on nuclear shapes based on electric quadrupole (E2) matrix elements. New beam development and experimental facilities funded through the GAMKA project have allowed the precise determination of E2 matrix elements at iThemba LABS [1,2]. The large oblate deformation determined in 60Ni is is inconsistent with the near-zero quadrupole...
The region around N≈60 with Z≤40 has generated considerable interest as it features the most abrupt shape transition known to date in the nuclear chart, when crossing from N=58 to N=60 [1]. This transition is closely linked to shape coexistence [2], a phenomenon where two or more states with different intrinsic shapes coexist within the same nucleus at low excitation energy and within a narrow...
Gold and platinum nuclei near the $N$ = 104 mid-shell, such as $^{182}$Au and $^{182}$Pt, have attracted considerable interest due to rapid changes in ground-state deformation compared to heavier isotopes. Additionally, a coexistence of at least two configurations, a weakly oblate and a prolate, has been observed for platinum isotopes in this region [1,2]. These phenomena have been extensively...
The Search for Hidden Particles (SHiP) experiment targets searching for feebly interacting particles (FIPs) with extremely weak couplings to the known standard model particles. For this, it will exploit the high-intensity proton beam from CERN’s Super Proton Synchrotron (SPS) in beam-dump mode to produce FIPs, such as heavy neutral leptons (HNLs), dark photons, dark scalars, axion-like...
Capture of thermal neutrons is a well-established experimental method to probe the structure of nuclei in the vicinity of the path of stability. This technique allows for population of excited states below the single-neutron separation energy and for studies of their properties via, for example, angular correlations or fast timing methods. However, the relatively large energy window that...
Abstract
The region near $^{78}\mathrm{Ni}$ is crucial for nuclear structure studies, as it lies around a doubly-magic shell closure ($Z = 28$, $N = 50$), making it an ideal testing ground for shell evolution and the interplay between single-particle and collective effects. Currently, many experimental and theoretical efforts are dedicated to investigating this region of...
To exploit the vast possibilities offered for research in nuclear structure, nuclear astrophysics and other fields at ISOLDE, the HIE-ISOLDE Timing Array for Reaction Studies (HISTARS) project aims at building a detection device for the measurement of lifetimes of excited states populated in reactions. Nuclear excited-state lifetimes are essential to have direct access to electromagnetic...
Since the discovery of large shape staggering in neutron-deficient mercury isotopes Z = 80 [1], the region around Z = 82 and N = 104 has been extensively studied using in-source laser spectroscopy, due to its intriguing nuclear structure phenomena [2-3]. Recent experiments have revealed substantial shape staggering in neighbouring bismuth isotopes Z = 83 starting at neutron number *N =...
This presentation provides an overview of CERN's Open Science policy and the comprehensive suite of services and tools available to support the CERN community in meeting policy requirements. We will explore the key principles underpinning CERN's commitment to open science, including open access to publications, research data management, and knowledge sharing. The session will showcase the...
The ISBM (Ion Sources and Beam Manipulation) team at ISOLDE is dedicated to the development and application of advanced techniques for radioactive ion beam (RIB) purification and preparation. This includes molecular beam extraction, laser ionization and background suppression methods, specialized devices such as fast beam gates, timed beam delivery systems, ion traps, and a variety of...
β-detected Nuclear Magnetic Resonance (β-NMR) is the method employed at VITO to measure the nuclear magnetic moments of unstable nuclei. In a β-NMR experiment at VITO, the main observable is the asymmetry between β-particles emitted along or opposite to the nuclear polarization direction, measured with detectors placed on opposite sides of the sample. The asymmetry for a given β-transition...
The region near the doubly magic nucleus $^{78}$Ni (Z = 28, N = 50) plays a key role in understanding shell evolution and the balance between single-particle and collective degrees of freedom [1]. It represents a critical testing ground for theories of nuclear structure far from stability and for constraining models of r-process nucleosynthesis. In this context, neutron-rich zinc isotopes...
The antiProton Unstable Matter Annihilation (PUMA) experiment aims to use low-energy antiprotons as a probe to investigate the proton-to-neutron ratio at the tail of nuclear density of unstable nuclei. Since no existing facility provides a collider of low-energy antiprotons and low-energy radioactive ions, PUMA proposes to bridge this gap by storing up to one billion antiprotons in a portable...
Beta-delayed fission (βDF) is a two-step process where a parent nucleus β-decays into a daughter nucleus that can then fission with a certain probability from an excited state [1]. The experimentally measured βDF probability (P$_{βDF}$) is often very small and has been studied mostly for neutron-deficient isotopes, while only a few cases have been reported on the neutron-rich side of the...
In this talk, I will present an overview of recent research at ISOLDE that bridges solid-state physics, quantum technologies, nuclear physics, and fundamental interactions. One of our main research directions focuses on understanding and controlling optically active impurity–vacancy complexes (color centers) in diamond, using radioactive isotopes as probes [1]. This work establishes...
Absolute transition strengths between excited states yield fundamental information on nuclear structure. These observables can be determined from level lifetimes. The recoil distance Doppler-shift (RDDS) technique employing so-called plunger devices provides a valuable method for the determination of lifetimes in the picosecond range and has been in the focus of our Cologne group since many...
The region of the nuclear landscape around the doubly-magic $^{132}$Sn is rich in nuclear structure phenomena. A relevant feature in the region is the presence of long-lived isomeric states, which may undergo both $\beta$ and $\gamma$ decay [1-3]. Spin-gap isomers arising from hindered decay routes to lower-lying levels due to a large change in nuclear spin the need for the emission of...
The magnetoelectric coupling effects and ferromagnetic properties of multiferroic bismuth ferrite (BiFeO₃, BFO) nanoparticles at the microscopic scale remain subjects of ongoing scientific discourse. In this study, two local hyperfine interaction techniques—time differential perturbed angular correlation (TDPAC) spectroscopy and transmission Mössbauer (TMS) spectroscopy—were employed to...
In the framework of the HISTARS (HIE-ISOLDE Timing Array for Reaction Studies) project at ISOLDE/CERN, an array is being developed to measure lifetimes of excited nuclear states populated in reactions at HIE-ISOLDE. For particles detection, plastics or fast inorganic scintillators such as GAGG:Ce and YSO are promising candidates due to their non-hygroscopic nature, high density, high light...
The Resonance Ionization Laser Ion Source (RILIS) continues to provide element-selective radioactive ion beams to users at the ISOLDE facility[1], serving as the laser ion source for over 50% of experiments in 2025. In addition to its high efficiency in producing pure radioactive ion beams, RILIS has been advancing its capabilities through the Laser Ion Source and Trap (LIST) technique,...
The charge states and lattice sites of Fe ions in both virgin and Mn-doped Al$_x$Ga$_{1-x}$N samples have been investigated by employing $^{57}$Fe emission Mössbauer spectroscopy (eMS) using radioactive $^{57}$Mn$^+$ ion implantation at ISOLDE, CERN. In undoped Al$_x$Ga$_{1-x}$N, Fe$^{2+}$ ions occupying Al/Ga lattice sites associated with nitrogen vacancies, as well as substitutional...
Multi-humped fission barriers, as observed in the actinide region, give rise to isomeric fission [1]. Such barrier shapes can be described using various theoretical models [2]. Experimentally measured observables of nuclear fission isomers - such as the half-life, excitation energy, kinetic-energy spectra of fission fragments, and the isomer-to-ground-state population ratio - serve as...
Following the N=28 shell closure, a pronounced change in the slope of the charge radii, often referred to as a "kink", has been observed in neutron-rich calcium isotopes [1,2]. However, the exact amplitude of this kink and the underlying reasons for this phenomenon remain unclear. Theoretical predictions suggest that several factors could contribute to this behaviour, including the presence of...
Due to its low excitation energy around 8.4 eV, the unique $^{229}$Th isomer is the ideal candidate for developing a nuclear clock [1]. Such a clock would be particularly suited for fundamental physics studies [1]. In the past, measuring the isomer's radiative decay from a large-bandgap crystal doped with $^{229}$Th, has proven difficult: the commonly used population of the isomer via the...
Shape coexistence in the neutron-deficient lead region around $N \approx 104$ has been discovered in different nuclei especially in the mercury isotopes, where a staggering effect was found between even- and odd-mass nuclei using charge radii measurements [1,2]. In addition the study of the even-even $^{182,184,186,188}$Hg isotopes via Coulomb excitation reactions showed a mixing of weakly...
