Title Promoter Affiliations Abstract "A new approach to lead isotope ratio data in archaeometry: the flow and recycling of materials and ideas" "Patrick Degryse" Geology "Conventional lead isotope biplots have proved useful in archaeological science, in particular to provenance the raw materials used in early pyrotechnologies. This approach does not work well, however, in case of anthropogenic mixing and recycling of materials. New approaches to the study of man-made materials have been proposed, looking at changes and similarities in the composition of assemblages, called the flow of ancient materials, rather than focusing on provenance as such. In this project, a new method to study the origin and recycling of materials using lead isotopic data is developed, integrating the principle of flow of materials and kernel density functions. This new technique will be applied to investigate the origin of antimony in the earliest glass and metal industries, and to reconstruct the flow of glass, lead and silver in the Greco-Roman world. Where the former case reconstructs the origin and distribution of a particular raw material, the latter allows to quantify recycling versus the influx of primary, fresh materials through time." "A new approach to lead isotope ratio data: the flow and recycling of materials and ideas" "Patrick Degryse" Geology "The main goal of this research project is to develop an innovative method to interpret lead isotope ratio data in archaeology, based on the three fundamental ratios measured in laboratory studies (208Pb/204Pb, 207Pb/204Pb, 206Pb/204Pb) and interpreting these with kernel density techniques (KDE). Though such KDE-based approach may be well developed in statistics, it has only been suggested and nearly never effectively used in archaeological science, thus going beyond the state of the art. This new method will be applied, in combination with other compositional data, in the study of two particular material categories, i.e. glass and metal, identifying and quantifying the input of fresh materials (from mineral resources) versus the continued reuse of previously formed materials (through recycling and mixing). In effect, the recycling of glass, silver and metallic lead on the scale of the Roman empire will be investigated. The focus in this project is on detecting and quantifying change over time and differences over space in the archaeological record. Mapping the ‘flow’ of glass, silver and lead in the late Bronze age and Roman Mediterranean world requires an answer to the questions: • What are the striking changes and similarities between the LIA ‘fingerprints’ of glass, silver and lead assemblages from subsequent time periods in the Roman world? • How can this continuity or change be interpreted? Is it possible, and to what extent, to identify the timing and origin of new input of fresh glass, silver and lead into the Roman system of material procurement? • For all these materials, is it possible to interpret changes in a social-geographical context, also taking into account material characteristics, archaeological context and manufacturing characteristics? Such inferences cannot be meaningfully made on the basis of individual analyses of isolated objects, but observations of change have to be made on the basis of group properties, giving sense to what is expected of the composition of a group of objects for a certain time and period. Existing ore and artefact data already assembled and available to the research group will be evaluated, complemented by targeted new analysis by MC-ICP-MS." "Coulomb excitation of Polonium isotopes." "Piet Van Duppen" "Nuclear and Radiation Physics, Faculty of Science" "The neutron-deficient polonium isotopes, with only 2 protons outside the Z = 82 shell closure, are situated in an interesting region of the nuclear chart. In the neighboring lead (Z = 82) and mercury (Z = 80) isotopes, experimental and theoretical efforts identified evidence of shape coexistence. Shape coexistence is the remarkable phenomenon in which two or more distinct types of deformation occur in states of the same angular momentum and similar excitation energy in a nucleus. The neutron-deficient polonium isotopes have also been studied intensively, experimentally as well as theoretically. The closed neutron-shell nucleus 210Po (N = 126) manifests itself as a two-particle nucleus where most of the excited states can be explained by considering the degrees of freedom of the two valence protons outside of 208Pb. The near-constant behavior of the yrast 2+ and 4+ states in the isotopes with mass A=200-208 can be explained by coupling the two valence protons to a vibrating lead core. 200Po seems to mark the end of this regular seniority-based character, with a sudden downsloping trend of almost all the excited states in the lighter isotopes with mass A" "The European medical isotope programme: Production of high purity isotopes by mass separation" "Thomas Elias Cocolios" "Nuclear and Radiation Physics, Radiopharmaceutical Research, Nuclear Medicine & Molecular Imaging" "PRISMAP - The European medical isotope programme: Production of high purity isotopes by mass separation proposes to federate a consortium of the key European intense neutron sources, isotope mass separation facilities and high-power accelerators and cyclotrons, with leading biomedical research institutes and hospitals active in the translation of the emerging radionuclides into medical diagnosis and treatment. PRISMAP will create a single-entry point for a fragmented user community distributed amongst universities, research centres, industry and hospitals, in a similar way as the National Isotope Development Center NIDC supported by the Department of Energy (DOE) has provided radionuclide sources for users in the USA. PRISMAP brings together a consortium of 23 beneficiaries from 13 countries, one European Research Laboratory and an International Organisation. It further receives support of leading associations and institutions in the field such as the European Association of Nuclear Medicine (EANM) and the International Atomic Energy Agency (IAEA). Our main goal is to provide a sustainable source of high purity grade new radionuclides for medicine, involving from the onset upcoming major European infrastructures, to provide a single-entry point for all researchers active in this field including SMEs, global pharma, nuclear centres, hospitals and universities, using standardised access procedures. The new isotope enrichment and standardisation techniques triggered in PRISMAP will expand our services and provide them to yet unreachable remote European laboratories. PRISMAP thus strives to create a paradigm shift in the early phase research on radiopharmaceuticals, targeted drugs for cancer – one of the major diseases in Europe - theranostics and personalised medicine, shaping the European isotope landmark as a gold standard to accelerate the development of the pharma industry and ultimately of a better healthcare for the improvement of our citizens’ life." "Laser spectroscopy of short-lived isotopes in the magic Tin region at ISOLDE-CERN." "Gerda Neyens" "Nuclear and Radiation Physics" "Is a nucleus spherical or deformed? Do nucleons behave as individual entities or should they be considered as the building blocks of a collective state? How does the structure of an atomic nucleus change when extreme amounts of protons or neutrons are present? These are only a few examples of questions on which this project mainly focuses. In cooperation with other international research teams and using the results of experimental and theoretical studies, probing the unknown properties of the strong interaction. To reach this goal, the research focuses on the structure of exotic nuclei, i.e. nuclei with extreme proton-to-neutron ratios. Especially among these isotopes, new nuclear phenomena appear such as changes in the conventional shell structure, the presence of new magic numbers, configuration mixing, shape coexistence, and nuclear deformation. The spin and the static moments of the nucleus are excellent probes to study nuclear structure. Over the years, the group has developed expertise in measurements of these static moments on short-lived isotopes, mainly using laser spectroscopy techniques. With these techniques, the nuclear moments are obtained from measurements of atomic hyperfine structure. The first observable we can access in this way is the mean square charge radius, which gives an indication of the extension of the nuclear charge in space. Additional insight into the charge distribution is obtained from the next electric observable, the electric quadrupole moment, which probes the average deviation of the nuclear charge distribution from a sphere. Complimentary to these electrical observables, the magnetic moments are sensitive to the quantum configuration of the valence nucleons. The study of nuclei close to proton and neutron shell closures is particularly appealing, as these nuclei represent the ideal test bed for state-of-the-art nuclear theory. 100Sn and 132Sn, with 50 protons and respectively 50 and 82 neutrons, are doubly magic nuclei according to the nuclear shell model; yet, 100 Sn itself and isotopes beyond 132 Sn are shortlived and challenging to produce and study, thus data is correspondingly scarce. The group has developed the efficient and selective high-resolution collinear resonance ionization spectroscopy technique at ISOLDE/CERN, which can cope with these low production rates of less than 100 isotopes/second. Within this Ph.D. project, the objective is to perform experiments on exotic isotopes close to Sn and from the data extract the nuclear electromagnetic moments, charge radii, and spin, to investigate the quantum structure and how it changes far from the valley of stable isotopes. In collaboration with nuclear theorists, testing the current state of the art in nuclear theory calculations. Joining or taking the lead in some technical upgrades that are needed to push the method to even higher sensitivity and selectivity, to enable the proposed studies." "Exploring the shell structure of exotic Sn isotopes with an Active Target." "Riccardo Raabe" "Nuclear and Radiation Physics" "Experiments performed at Radioactive Ion Beam facilities are shedding new light on nuclear physics and nuclear structure, as well as nuclear astrophysics, materials science and medical science, opening unexpected scenarios in this fields of research. In this project we aim at a deeper understanding of the behavior of the Nuclear Force in the region of the unstable 132Sn nucleus, where the excess of neutrons can lead to significant changes in the expected “shell structure” of nuclei. The many existing facilities, as well as the new generation of facilities being built worldwide and those proposed for the future, are a testament to the high interest in this rapidly expanding field. They are allowing - and are going to extend - the exploration of regions of the Nuclear Chart otherwise unaccessible. This requires the development of new specific tools in order to fully exploit the outreach capabilities of such machines. In this project the use of an ""Active Target"", a gaseous detector, is foreseen to perform Nuclear Structure studies through direct reactions. The use of state of the art technologies, like Silicon Photomultipliers and Graphics Processing Units, is also introduced in order to further upgrade the Active Target Device." "Laser and decay spectroscopy of neutron-deficient radioactive nuclei in the lead region (Z=82)." "Mark Huyse" "Nuclear and Radiation Physics" "The fundamental interactions that are important to explain the properties of an atom are the electromagnetic force, that keep the electrons circling around the atomic nucleus, the weak force, that is responsible for nuclear beta decay which represents an important form of radioactivity, and the strong force, that keeps the protons and neutrons (also called nucleons) together in the nucleus. The electromagnetic force is well known, but the strong- and weak forces are still poorly known. For example calculations that start from basic principles can only predict the properties of the atomic nucleus to a reasonable degree of accuracy up to atoms with twelve nucleons. While atoms with up to three hundred nucleons exist. This proposal aims to learn more about the strong force in these heavier nuclei in order to improve our knowledge of the strong force. This is not only important for our understanding of these fundamental forces in nature, but also for solving questions such as how were the chemical elements made in the universe or what makes the stars shine? Recently it has been realized that some of the hidden secrets of the atomic nucleus might be discovered by studying atoms with an unusual ratio between the number of protons and neutrons. Unfortunately, these atoms are not available on earth as they are radioactive and disappear pretty soon after they have been produced. We have developed a technique to produce these radioactive atoms of interest, to shape them into a radioactive ion beam and to produce point-like and pure sources, surrounded by detectors. The radiation that is emitted in this process gives direct information on the properties of the atomic nucleus. These can in turn be used to fine tune our models and uncover hidden aspects of the strong force. But the production process itself can also reveal important information on the strong force and on the atomic structure of these heavy elements as we use laser light to ionize the atoms of interest. This ultra-sensitive method could also be of interest for the production of medical radio-isotopes of for trace detection. The  experiments are performed at the radioactive ion beam facility ISOLDE at CERN where a new project to substantially improve the intensity and quality of the beams and to accelerate radioactive ion beams to even higher energies (called HIE-ISOLDE) is now in full realization." "Collinear Resonance Ionization Spectroscopy of potassium isotopes: crossing N=32" "Gerda Neyens" "Nuclear and Radiation Physics" "Understanding the properties of unstable nuclei has been a long-standing problem. In particular, the emergence and disappearance of so called magic numbers has attracted significant attention in recent years, both from the theoretical and experimental side. This thesis aims to contribute to the field of nuclear physics through the measurement of the ground state nuclear magnetic moments and the changes in the mean-square charge radii of neutron-rich potassium (K) isotopes (Z = 19). The K isotopes are within the reach of the state-of-the-art theoretical calculations and therefore serve as an excellent laboratory for testing new developments. Furthermore, in the Ca region new subshell closures are expected to emerge at neutron numbers N = 32 and N = 34. The study of 52K, which has N = 33 neutrons, allows for the investigation of the magic nature of N = 32 by looking at the evolution of the size of K isotopes leading up to and across N = 32. Furthermore, from the nuclear magnetic moment, the ground state configuration of this isotope can be extracted and compared to the empirical and theoretical estimates, further testing the magicity of N = 32 and Z = 20. The Collinear Resonance Ionization Spectroscopy technique was used for performing the measurements discussed in this thesis. First, the optimization of a resonance ionization scheme which provides high spectral resolution and high efficiency is presented. Next, developments towards improved precision are discussed. Both of these were essential to ensure the reliability of the results obtained with the CRIS technique, previously only used to study heavier systems. A simple decay station was assembled which could detect the decay of the short-lived K isotopes, while being insensitive to the non-resonantly ionized stable contamination. This way, the selectivity of the technique can be drastically improved. The aforementioned developments lead to the successful measurement of the hyperfine structure of 52K. The newly determined nuclear spin of this isotope supports the previous tentative assignment of I = 2. The experimental nuclear magnetic moment is well reproduced by shell model calculations using the SDPF-U interaction. The rather pure ground state wavefunction is dominated by the coupling between the proton in the d3/2 and the neutron in the p1/2 orbital. The change in the mean-square charge radius fits into the smoothly increasing trend of radii in the K chain above N = 28 and doesn’t feature a kink, normally expected at shell closures. Furthermore, the charge radii were compared to state-of-the-art coupled cluster calculations using a new NNLO interaction derived from chiral effective theory. The disagreement between theoretical predictions and experimental values in the vicinity of N = 32 might indicate that the nuclear structure of these isotopes is more complex than expected." "Hot or Cold? Did changes in volcanic activity influence global temperature evolution throughout geological climate-change events" "Philippe Claeys, Lawrence Percival" "Analytical, Environmental & Geo-Chemistry, Chemistry" "Earth’s history has been marked by frequent episodes of global-scale marine anoxia and organic-matter burial, particularly in the Cretaceous, Devonian, and Silurian. CO2 emissions associated with large igneous provinces are thought to have caused rapid climate warming during the Cretaceous events (e.g., Early Aptian oceanic anoxic event; OAE 1a: ~120 Ma). However, OAE 1a also featured transient cold pulses during the overarching warming, whilst the Devonian and Silurian events (e.g., Frasnian–Famennian crisis: ~372 Ma) were typically characterized by global cooling. It is unclear whether the OAE 1a cooling pulses reflect a volcanic hiatus or enhanced CO2 drawdown via silicate weathering/organic-matter burial. A further question is whether the Devonian and Silurian crises were initiated by volcanism, but with any warming effect totally offset by carbon burial, or had a different trigger to the Cretaceous anoxic events. This proposal employs two widely-used proxies of volcanism (mercury contents and osmium isotopes) to study records of the Cretaceous, Devonian, and Silurian events, focusing on sites that document palaeoclimate trends, enabling direct comparison between changes in volcanic activity and global temperatures. These results will highlight the extent to which volcanism operated during each cooling episode, and thus the importance of volcanic activity in controlling global temperatures at those times." "Liquid chromatograph interfaced with an isotope ratio mass spectrometry detector (LC-IRMS)" "Pascal Boeckx" "Department of Green Chemistry and Technology, Department of Applied analytical and physical chemistry" "The Isotope Bioscience Laboratory (ISOFYS) of the promoter-spokesperson is a centre of excellence holding unique expertise and equipment for analyses and applications of stable isotopes of light elements (H,C,N,O,S) ISOFYS currently manages eight platforms for stable isotope analyses, which foster interdisciplinary collaboration with UGent and (inter)national research groups, as the importance of stable isotopes for (life) science has steadily been growing since the 1990's. The requested equipment is a liquid chromatograph interfaced with an isotope ratio mass spectrometry detector (LC-IRMS). An IRMS detector is a mass spectrometer specially designed to measure isotopic composition of 2H (D), 13C, 15N, 18O and 34S at natural abundance level. The fundamental difference with other mass spectrometry detectors is that adjacent masses are detected simultaneously rather than consequently, leading to isotope ratio measurements with outstanding precision and accuracy. Isotopic composition can be determined at elemental level on a bulk sample (e.g. a plant leaf) or at molecular level by coupling IRMS to a chromatographic system (e.g. individual sugars extracted from a leaf)."