In the case of high-fluence implantations, the approximation that every new incoming particle interacts with a pristine substrate material no longer holds. Dynamical changes to the substrate can induce different phenomena, one of which is self-sputtering. Self-sputtering occurs when incoming ions remove previously implanted ions from the implantation substrate. This phenomenon is significant in target production for nuclear structure studies and medical radionuclide separation, where self-sputtering limits can be reached during isotope implantation. Self-sputtering can be modeled using TRIDYN simulations in order to guide implantations. This work explores the ability of TRIDYN to give order-of-magnitude estimates for the onset of self-sputtering for these nuclear physics applications. This is performed through the implantation of Yb in Zn and Al, relevant to both fundamental and medical nuclear physics research. Our findings indicate that TRIDYN predicts general dependencies reasonably well. However, it is important to carefully consider input parameters and validity of the TRIDYN simulations. Copyright M. Heines et al. This work is licensed under the Creative Commons Attribution 4.0 International License. Published by the SciPost Foundation.

Lead-212 has emerged as a promising radionuclide for targeted alpha therapy (TAT), positioning itself at the forefront of next-generation cancer treatments. What sets lead-212 apart is its unique decay profile: while it is a beta emitter, it mainly serves as an in vivo generator of the potent alpha-emitting daughter radionuclide bismuth-212. This characteristic offers a versatile radiobiological profile, potentially optimizing therapeutic efficacy by combining the radiochemical characteristics of lead-212 such as easy radiolabeling and practical half-life, with the therapeutic benefit of alpha particles. The relatively short half-life of lead-212 (10.6 hours) offers favorable dosimetric properties, enabling effective treatment while minimizing long-term radiation exposure. Its gamma-emitting analogue, lead-203, is well-suited for single-photon emission computed tomography (SPECT) imaging, forming an ideal theranostic matched pair that can significantly accelerate preclinical and clinical research. Crucially, the generator-based production of lead-212 enables decentralized and on-demand availability, but its half-life also allows centralized production, facilitating broad clinical access and logistical flexibility. In this review, the advantages and challenges of lead-based radiopharmaceuticals are discussed, covering the entire chain from radionuclide production to bedside administration. Special attention is given to the coordination chemistry of lead, and we give an overview of available bifunctional chelators. We also present the latest advancements in preclinical and clinical applications and conclude with perspectives on future directions of lead-based theranostics.

The ionization potential (IP) of radium monofluoride (RaF) was measured to be 4.969(2)[10] eV, revealing a relativistic enhancement in the series of alkaline earth monofluorides. The results are in agreement with a relativistic coupled-cluster prediction of 4.981(7) eV, incorporating up to quantum electrodynamics corrections. Using the same computational methodology, an improved calculation for the dissociation energy (D_{0}) of 5.54(5) eV is presented. This confirms that RaF joins the group of diatomic molecules for which D_{0}>IP, paving the way for precision control and interrogation of its Rydberg states.

Precise experimental control and interrogation of molecules and calculations of their structure are enriching the investigation of nuclear and particle physics phenomena. Molecules containing heavy, octupole-deformed nuclei, such as radium, are of particular interest. Here, we report precision laser spectroscopy measurements and theoretical calculations of the structure of the radioactive radium monofluoride molecule 225Ra19F. Our results reveal fine details of the short-range electron-nucleus interaction, indicating the high sensitivity of this molecule to the distribution of magnetization, within the radium nucleus. These results provide a stringent test of the description of the electronic wave function inside the nuclear volume, highlighting the suitability of these molecules for investigating subatomic phenomena.

A comparative vacuum ultraviolet spectroscopy study conducted at ISOLDE-CERN of the radiative decay of the ^{229m}Th nuclear clock isomer embedded in different host materials is reported. The ratio of the number of radiative decay photons and the number of ^{229m}Th embedded are determined for single crystalline CaF_{2}, MgF_{2}, LiSrAlF_{6}, AlN, and amorphous SiO_{2}. For the latter two materials, no radiative decay signal was observed and an upper limit of the ratio is reported. The radiative decay wavelength was determined in LiSrAlF_{6} and CaF_{2}, reducing its uncertainty by a factor of 2.5 relative to our previous measurement. This value is in agreement with the recently reported improved values from laser excitation.

Muonic atom spectroscopy is a method that can determine absolute nuclear charge radii with typical relative precision of $$10^{-3}$$ . Recent developments have enabled to extend muonic atom spectroscopy to microscopic target quantities as low as $$5\,{\upmu }\text {g}$$ . This substantial reduction from the traditional limit of the order of $$100\,\text {mg}$$ is based on a transfer mechanism in a high-pressure hydrogen gas cell, which transports the muon to the surface of the target material rather than stopping it over a broad depth range. This approach enables the measurement of absolute nuclear charge radii of long-lived radioactive isotopes (half-life above $$\sim$$ 20 years), but the production of appropriate targets for the technique has presented some major challenges, such as the formation of organic layers on the substrate. This study presents a systematic investigation of the stopping efficiency for different target preparation methods: ion implantation, drop-on-demand printing, and molecular plating. Notable differences between the three methods were discovered in terms of their performance allowing to further fine tune the method of choice for future target preparations. Our findings show that implantation provides appropriate targets for our method with negligible losses. This achievement opens the landscape of potential measurements to isotopes where high mass separation is required not achievable with other methods. Furthermore, molecular plated targets performed substantially better than those prepared using drop-on-demand printing.

This paper reports on the measurement of the ground-state spin and nuclear magnetic dipole moment of 61Cr. The radioactive ion beam was produced at the CERN-ISOLDE facility and was probed using high-resolution resonance ionization laser spectroscopy with the collinear resonance ionization spectroscopy (CRIS) apparatus. The present ground-state spin measurement I = 12, differing from the previously adopted I = (52 ), has significant consequences on the interpretation of existing beta decay data and nuclear structure in the region. The structure and shape of 61Cr is interpreted with state-of-the-art Large-Scale Shell-Model and Discrete NonOrthogonal Shell-Model calculations. From the measured magnetic dipole moment mu (61Cr) = +0.541(6)mu N and the theoretical findings, its configuration is understood to be driven by two-particle-two-hole neutron excitations with an unpaired 1p1/2 neutron. This establishes the western border of the N = 40 island of inversion, characterized by four-particle-four-hole neutron components. We discuss the shape evolution along the Cr isotopic chain as a second-order quantum phase transition at the entrance of the N = 40 island of inversion.

At CERN-ISOLDE, high-purity radioactive ion beams of 219Fr and 221RaF were investigated with α-decay spectroscopy at the CRIS and ASET experiments in the course of three different experimental campaigns. The half-life of 215At, α-decay daughter of 219Fr, is measured to be 36.3(3)[9]μs, and that of 221Ra was determined to be 26.2(1)[6]s, both of which are well in line with the trends in this region of the nuclear landscape but at odds with some of the reported literature.

The radiative lifetime of the A (2)Pi(1/2) (v = 0) state in radium monofluoride (RaF) is measured to be 35(1) ns. The lifetime of this state and the related decay rate Gamma = 2.86(8) . 86(8) x 107 7 s-1 - 1 are of relevance to the laser cooling of RaF via the optically closed A (2)Pi(1/2) <- X (2)Sigma(1/2) transition, which makes the molecule a promising probe to search for new physics. RaF is found to have a comparable photon-scattering rate to homoelectronic laser-coolable molecules. Owing to its highly diagonal Franck-Condon matrix, it is expected to scatter an order of magnitude more photons than other molecules when using just three cooling lasers, before it decays to a dark state. The lifetime measurement in RaF is benchmarked by measuring the lifetime of the 8P3/2 P 3 / 2 state in Fr to be 83(3) ns, in agreement with literature.

A detailed level scheme of 213Fr126 following the EC/beta+ decay of the 1/2- 213 Ra parent ground state was built in an experiment performed at the ISOLDE Decay Station, CERN. The fragmented total beta decay strength favours the direct population of several low-spin (J 7/2) excited states. The analysis of the gamma-singles spectrum and gamma-gamma coincidences allowed us to identify many new gamma-ray transitions and excited states in 213 Fr up to about 3.6 MeV excitation energy. The spins and parities of the newly established levels, on top of the (7/2-1 ) state, were mainly assigned based on the systematics of the N = 126 isotones and further compared with shell-model calculations. The level scheme displays a structural pattern, with several groups of states with negative parity, emerging from the well-defined, simple, pi ( h 59 / 2 ), pi ( h 4 9 / 2 f 17 / 2 ) configurations or from their configuration mixing. The strength of the E 2 transitions within the multiplets is compared with shell-model theoretical calculations performed with the KHPE and H 208 effective interactions. A new (3/2-) isomer with a half-life of 26(3) ns has been identified. An upper limit of 35 ps was determined for the half-life of the first excited state, 7/2-. The possibility of a mixed M 1 + E 2 character is discussed for the 7/2-1 -> 9/2-gs decay in 213 Fr, which leads to an l-forbidden nature of the pi f 7 / 2 -> pi h 9 / 2 transition.

ISOL@MYRRHA will be a new Radioactive Ion Beam (RIB) facility in Belgium based on the Isotope Separation On-Line (ISOL) technique, and established within the framework of MYRRHA, the world’s first large-scale accelerator driven system project at power levels scalable to industrial systems. The surface ion source, or hot cavity, is chosen as initial source for its reliability and simple design. To account for the higher flux of atoms through this cavity, a theoretical study of the processes within the ion source is discussed here, based on theoretical equations and thermal-electric simulations. In the past, the temperature was clearly identified as a key element to this source, but with the assumption that it remains constant throughout the cavity. Nonetheless, more recent thermal-electric simulations have revealed that the source Ohmic heating leads to temperature gradients along the cavity tube. The temperature profile impact on ionisation in the hot cavity will be reviewed here.

The QUARTET collaboration aims to significantly improve the precision of the absolute nuclear charge radii of light nuclei from Li to Ne by using an array of metallic magnetic calorimeters to perform high-precision X-ray spectroscopy of low-lying states in muonic atoms. A proof-of-principle measurement with lithium, beryllium and boron is planned for fall 2023 at the Paul Scherrer Institute. We discuss the performance achieved with the maXs-30 detector module to be used. To place the detector close to the target chamber where the muon beam will impact the material under study, we have developed a new dilution refrigerator sidearm. We further discuss the expected efficiency given the transparency of the X-ray windows and the quantum efficiency of the detector. The expected muonic X-ray rate combined with the high resolving power and detection efficiency of the detector suggest that QUARTET will be able to study the de-excitation of light muonic atoms at an unprecedented level, increasing the relative energy resolution by up to a factor of 20 compared to conventional detector techniques.

The changes in the mean-squared charge radius of Tlg209 (N=128) and Tlm207 (N=126) relative to Tl205 have been measured for the first time using the in-source laser resonance-ionization spectroscopy technique with the Laser Ion Source and Trap (LIST) at ISOLDE (CERN). The application of the LIST suppresses the dominant background from isobaric francium isotopes and allows access to thallium nuclides with A⩾207. The characteristic kink in the charge radii at the N=126 neutron shell closure, as well as the odd-even effect similar to that in the adjacent bismuth, lead, and mercury isotopic chains, have been observed. The self-consistent theory of finite Fermi systems based on the energy density functional by Fayans reproduces the behavior of charge radii in these isotopic chains near N=126. The comparison with calculations in the framework of the relativistic mean field (RMF) approach is also presented. In the case of the Fayans functional it is a specific form of pairing interaction with the dependence on the density gradient that is essential to provide agreement with the experimental charge radii. In particular, the kink is reproduced without the inversion of g9/2 and i11/2 neutron single-particle states, which is a prerequisite to correctly describe the kink in the RMF models. Published by the American Physical Society 2024

In the field of medical and scientific research, radionuclides are used to investigate various physiological and pathological processes. PRISMAP - the European medical radionuclide programme was created to bring together production facilities including intense neutron sources, an isotope mass separation facility, high-power accelerators, biomedical research institutes, and hospitals to support medical research. The aim of this article is to introduce readers with the current status of innovative radionuclides in Europe. A survey was created targeting the latest trends mainly focused on the demand, the production and the distribution of non-routinely used medical radionuclides for use in research, and for pre-clinical and clinical trials. This survey has been disseminated through the PRISMAP community. 16 of 104 respondents were working in the field of radionuclide production. The data found common aspects from all producer-facility respondents: the biggest challenge for the producers is the availability of target materials, which goes hand-in-hand with their purity/enrichment grade. The results show that there are sufficient national or international distribution routes and methods established, although having reported challenges due to legislation constraints, especially for novel radionuclides. Thanks to a questionnaire distributed by the PRISMAP consortium, the current status in radionuclides production was identified. Understanding the current status of radionuclide production is essential for assessing the continent’s capabilities and addressing the burgeoning demands for cutting-edge medical radionuclides.

AbstractThe presented paper discusses the production of radioactive ion beams of francium, radium, and actinium from thick uranium carbide (UC$$_{x}$$ x ) targets at ISOLDE, CERN. This study focuses on the release curves and extractable yields of francium, radium and actinium isotopes. The ion source temperature was varied in order to study the relative contributions of surface and laser ionization to the production of the actinium ion beams. The experimental results are presented in the form of release parameters. Representative extractable yields per $$\mu$$ μ C are presented for $$^{222-231}$$ 222 - 231 Ac, several Ra and Fr isotopes in the mass ranges 214$$\le$$ ≤ A$$\le$$ ≤ 233 and 205$$\le$$ ≤ A$$\le$$ ≤ 231 respectively. The release efficiency for several isotopes of each of the studied elements was calculated by comparing their yields to the estimated in-target production rates modeled by CERN-FLUKA. The maximal extraction efficiency of actinium was calculated to be 2.1(6)% for a combination of surface ionization using a Ta ion source and resonant laser ionization using the two-step 438.58 nm, and 424.69 nm scheme.

CERN-MEDICIS is an isotope mass separation facility dedicated to biomedical research located in a type A work sector, receiving on average 50% of the 1.4 GeV protons delivered by the Proton Synchrotron Booster (PSB). It was commissioned with Radioactive Ion Beams (RIB’s) in 2017. MEDICIS has operated for the past 5 years in batch mode, with targets irradiated in a station located at the HRS beam dump, and with external sources provided by MEDICIS cyclotrons and nuclear reactors partners, notably during the Long Shutdown (LS2). Additional features of the facility include the MELISSA laser ion source, radiochemistry on implanted radionuclides and an online gamma-ray spectroscopy implantation monitoring. In 2022, we introduced Key Performance Indicators (KPI’s) to monitor the operation of the facility for collected efficiencies, the optimisation of the radiological risks and evaluate impact of possible modifications of the station, paralleling for instance LHC’s integrated luminosity. Defined KPI’s cover aspects in the operation cycle, e.g. planning in CERN schedule, target irradiations, duration of the process, radiological risk mitigation, facility up-time, developments and maintenance. MEDICIS KPI’s can help distinguish which of the operation and infrastructure life cycle requires immediate intervention, developments or consolidation. Those are related to the irradiation stations and irradiation possibilities, the beamlines (parallel collections), target and ion sources (reliability), robot handling and infrastructure, or the separation process itself.

The radiative lifetime of the AΠ1/22 (v=0) state in radium monofluoride (RaF) is measured to be 35(1) ns. The lifetime of this state and the related decay rate Γ=2.86(8)×107 s−1 are of relevance to the laser cooling of RaF via the optically closed AΠ1/22←XΣ1/22 transition, which makes the molecule a promising probe to search for new physics. RaF is found to have a comparable photon-scattering rate to homoelectronic laser-coolable molecules. Owing to its highly diagonal Franck-Condon matrix, it is expected to scatter an order of magnitude more photons than other molecules when using just three cooling lasers, before it decays to a dark state. The lifetime measurement in RaF is benchmarked by measuring the lifetime of the 8P3/2 state in Fr to be 83(3) ns, in agreement with literature. Published by the American Physical Society 2024

Terbium features four clinically interesting radionuclides for application in nuclear medicine: terbium-149, terbium-152, terbium-155, and terbium-161.Their identical chemical properties enable the synthesis of radiopharmaceuticals with the same pharmacokinetic character, while their distinctive decay characteristics make them valuable for both imaging and therapeutic applications.In particular, terbium-152 and terbium-155 are useful candidates for positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging, respectively; whereas terbium-149 and terbium-161 find application in α-and β --/Auger electron therapy, respectively.This unique characteristic makes the terbium family ideal for the "matched-pair" principle of theranostics.In this review, the advantages and challenges of terbium-based radiopharmaceuticals are discussed, covering the entire chain from radionuclide production to bedside administration.It elaborates on the fundamental properties of terbium, the production routes of the four interesting radionuclides and gives an overview of the available bifunctional chelators.Finally, we discuss the preclinical and clinical studies as well as the prospects of this promising development in nuclear medicine.

Our understanding of nuclear properties in the vicinity of 100Sn, suggested to be the heaviest doubly magic nucleus with equal numbers of protons (Z=50) and neutrons (N=50), has been a long-standing challenge for experimental and theoretical nuclear physics. Contradictory experimental evidence exists on the role of nuclear collectivity in this region of the nuclear chart. Using precision laser spectroscopy, we measured the ground-state electromagnetic moments of indium (Z=49) isotopes approaching the N=50 neutron number down to 101In, and nuclear charge radii of 101-131In spanning almost the complete range between the two major neutron closed-shells at N=50 and N=82. Our results for both nuclear charge radii and quadrupole moments reveal striking parabolic trends as a function of the neutron number, with a clear reduction toward these two neutron closed-shells, thus supporting a doubly magic character of 100Sn. Two complementary nuclear many-body frameworks, density functional theory and ab initio methods, elucidate our findings. A detailed comparison with our experimental results exposes deficiencies of nuclear models, establishing a benchmark for future theoretical developments.