Smooth trends in fermium charge radii and the impact of shell effects.

The quantum-mechanical nuclear-shell structure determines the stability and limits of the existence of the heaviest nuclides with large proton numbers Z ≳ 100 (refs. ). Shell effects also affect the sizes and shapes of atomic nuclei, as shown by laser spectroscopy studies in lighter nuclides.

Target Development towards First Production of High-Molar- Activity Sc and Sc by Mass Separation at CERN-MEDICIS.

The radionuclides Sc, 44g/mSc, and Sc can be produced cost-effectively in sufficient yield for medical research and applications by irradiating natTi and natV target materials with protons. Maximizing the production yield of the therapeutic Sc in the highest cross section energy range of 24-70 MeV results in the co-production of long-lived, high-γ-ray-energy Sc and Sc contaminants if one does not use enriched target materials. Mass separation can be used to obtain high molar activity and isotopically pure Sc radionuclides from natural target materials; however, suitable operational conditions to obtain relevant activity released from irradiated natTi and natV have not yet been established at CERN-MEDICIS and ISOLDE.

Opportunities for fundamental physics research with radioactive molecules.

Molecules containing short-lived, radioactive nuclei are uniquely positioned to enable a wide range of scientific discoveries in the areas of fundamental symmetries, astrophysics, nuclear structure, and chemistry. Recent advances in the ability to create, cool, and control complex molecules down to the quantum level, along with recent and upcoming advances in radioactive species production at several facilities around the world, create a compelling opportunity to coordinate and combine these efforts to bring precision measurement and control to molecules containing extreme nuclei. In this manuscript, we review the scientific case for studying radioactive molecules, discuss recent atomic, molecular, nuclear, astrophysical, and chemical advances which provide the foundation for their study, describe the facilities where these species are and will be produced, and provide an outlook for the future of this nascent field.

Observation of the radiative decay of the Th nuclear clock isomer.

The radionuclide thorium-229 features an isomer with an exceptionally low excitation energy that enables direct laser manipulation of nuclear states. It constitutes one of the leading candidates for use in next-generation optical clocks. This nuclear clock will be a unique tool for precise tests of fundamental physics.

Resonant laser ionization and mass separation of Ac.

[Formula: see text]Ac is a radio-isotope that can be linked to biological vector molecules to treat certain distributed cancers using targeted alpha therapy. However, developing [Formula: see text]Ac-labelled radiopharmaceuticals remains a challenge due to the supply shortage of pure [Formula: see text]Ac itself. Several techniques to obtain pure [Formula: see text]Ac are being investigated, amongst which is the high-energy proton spallation of thorium or uranium combined with resonant laser ionization and mass separation.

Exploring the Potential of High-Molar-Activity Samarium-153 for Targeted Radionuclide Therapy with [Sm]Sm-DOTA-TATE.

Samarium-153 is a promising theranostic radionuclide, but low molar activities (Am) resulting from its current production route render it unsuitable for targeted radionuclide therapy (TRNT). Recent efforts combining neutron activation of 152Sm in the SCK CEN BR2 reactor with mass separation at CERN/MEDICIS yielded high-Am 153Sm. In this proof-of-concept study, we further evaluated the potential of high-Am 153Sm for TRNT by radiolabeling to DOTA-TATE, a well-established carrier molecule binding the somatostatin receptor 2 (SSTR2) that is highly expressed in gastroenteropancreatic neuroendocrine tumors.

Ion implantation of Ra for a primary Rn emanation standard.

Laser resonance ionization at the RISIKO 30 kV mass separator has been used to produce isotopically and isobarically pure and well quantified Rn emanation standards. Based upon laser-spectroscopic preparation studies, ion implantation into aluminum and tungsten targets has been carried out, providing overall implantation efficiencies of 40% up to 60%. The absolute implanted activity of Ra was determined by the technique of defined solid-angle α-particle spectrometry, where excellent energy resolution was observed.

Terbium Medical Radioisotope Production: Laser Resonance Ionization Scheme Development.

Terbium (Tb) is a promising element for the theranostic approach in nuclear medicine. The new CERN-MEDICIS facility aims for production of its medical radioisotopes to support related R&D projects in biomedicine. The use of laser resonance ionization is essential to provide radioisotopic yields of highest quantity and quality, specifically regarding purity.

Efficient Production of High Specific Activity Thulium-167 at Paul Scherrer Institute and CERN-MEDICIS.

Thulium-167 is a promising radionuclide for nuclear medicine applications with potential use for both diagnosis and therapy ("theragnostics") in disseminated tumor cells and small metastases, due to suitable gamma-line as well as conversion/Auger electron energies. However, adequate delivery methods are yet to be developed and accompanying radiobiological effects to be investigated, demanding the availability of Tm in appropriate activities and quality. We report herein on the production of radionuclidically pure Tm from proton-irradiated natural erbium oxide targets at a cyclotron and subsequent ion beam mass separation at the CERN-MEDICIS facility, with a particular focus on the process efficiency.

Production of Sm-153 With Very High Specific Activity for Targeted Radionuclide Therapy.

Samarium-153 (Sm) is a highly interesting radionuclide within the field of targeted radionuclide therapy because of its favorable decay characteristics. Sm has a half-life of 1.93 d and decays into a stable daughter nuclide (Eu) whereupon β particles [E = 705 keV (30%), 635 keV (50%)] are emitted which are suitable for therapy.

CERN-MEDICIS: A Review Since Commissioning in 2017.

The CERN-MEDICIS (MEDical Isotopes Collected from ISolde) facility has delivered its first radioactive ion beam at CERN (Switzerland) in December 2017 to support the research and development in nuclear medicine using non-conventional radionuclides. Since then, fourteen institutes, including CERN, have joined the collaboration to drive the scientific program of this unique installation and evaluate the needs of the community to improve the research in imaging, diagnostics, radiation therapy and personalized medicine. The facility has been built as an extension of the ISOLDE (Isotope Separator On Line DEvice) facility at CERN.

The electron affinity of astatine.

One of the most important properties influencing the chemical behavior of an element is the electron affinity (EA). Among the remaining elements with unknown EA is astatine, where one of its isotopes, At, is remarkably well suited for targeted radionuclide therapy of cancer. With the At anion being involved in many aspects of current astatine labeling protocols, the knowledge of the electron affinity of this element is of prime importance.

High-resolution laser resonance ionization spectroscopy of Pm.

We present the results of high-resolution laser spectroscopy of the long-lived radioactive isotopes Pm. The hyperfine structures and isotope shifts in two different atomic ground-state transitions at 452 nm and 468 nm were probed by in-source laser spectroscopy at the RISIKO mass separator in Mainz, using the PI-LIST ion source. From the hyperfine coupling constants the nuclear magnetic dipole and electric quadrupole moments for Pm were derived, and the measured isotope shifts allowed the extraction of changes in nuclear mean square charge radii.