Electrodeposition is an attractive strategy for the purification and separation of radionuclides. Applications include their production for uses related to cancer diagnostic and therapy, their analytical characterization, and fundamental studies of the chemical properties of radioelements, including superheavy elements. In many of the mentioned applications, short-lived radionuclides are present in ultra-trace quantities. As a result, their electrodeposition is largely influenced by underpotential deposition (UPD) and cannot be studied by conventional electrochemical means. The aim of this work was the design and implementation of a methodology which enables the study of the electrodeposition behavior of short-lived radionuclides at carrier-free conditions. These were obtained in the form of fission products from the neutron-induced fission of 235U and their transport via the gas-jet technique. A mixer-degasser unit was implemented for the direct online transfer of approximate to 50% radionuclide-loaded aerosol particles into the liquid phase. This enabled the interfacing of the SINQ gas-jet system with a flow-through electrolysis cell for the cathodic electrodeposition of short-lived 134Te as proof-of-concept. Based on a comparison with results from cyclic voltammetry, UPD was shown to be the main mechanism responsible for the electrodeposition of 134Te on Au and Pt. Furthermore, it could be demonstrated that UPD affords a fast separation of short-lived radionuclides in carrier-free conditions by fine-tuning the electrode material and chemical conditions. The developed approach enables the determination of electrochemical properties of short-lived radionuclides via their separation at carrier-free concentrations.

The AGGIE gas-filled separator has been installed at the Cyclotron Institute at Texas A&M University and is now in routine use. Named Albert Ghiorso's Gas-filled Ion Equipment and formerly known as SASSY II and later SASSYER, the separator has a DvQhDv configuration and is currently used for nuclear reaction studies and online chemistry experiments. This manuscript describes the separator and experiments to measure its transmission, which was found to be approximate to 22% using the 164Dy(40Ar, xn)204-xPo reactions. Additionally, an investigation into AGGIE's ability to measure beam luminosity with a new, diamond detector was performed. The response of the diamond detector was characterized relative to the traditionally used silicon detector. The diamond detector was found to be overall suitable for luminosity measurements with a notable improvement in radiation hardness as evaluated based on the centroid, spectroscopic resolution and count rate of the implanting ions, thus minimizing potential for downtime while replacing detectors during an irradiation.

Isothermal vacuum adsorption chromatography (IVAC) in the molecular-flow regime offers the speed and chemical selectivity needed to study superheavy elements beyond flerovium (Fl, Z = 114). In this study, the GLACIER buffer gas cell and RF quadrupole combination was coupled with IVAC behind the gas-filled separator AGGIE for benchmark experiments with short-lived mercury radioisotopes 179Hg (t 1/2 = 1.05(3) s) and 178Hg (t 1/2 = 0.2665(24) s). GLACIER provided stable transport conditions over multiple days thereby enabling a clean chromatographic separation of Hg from less-volatile nuclear reaction byproducts on fused silica. These experiments validated the employed microscopic-kinetic transport model at zero surface coverage implemented in the form of a Monte Carlo simulation. The presented findings render this approach applicable to superheavy elements such as moscovium (Mc, Z = 115).

This study provides insights into the formation of Tb/Pd films produced by electroplating in combination with the so-called coupled reduction technique. The use of 149Tb as an α-emitting radionuclide enabled for the first time the study of the distribution of Tb across the surface and along the thickness of the Pd bulk by means of radiography and α-spectroscopy combined with Monte Carlo simulations of the energy loss of emitted α-particles, respectively. Additionally, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy were employed for surface analysis, whereas X-ray diffraction provided conclusive evidence of the formed crystalline phases. The obtained results indicate the formation of either the intermetallic phase TbPd3 or a Tb/Pd solid solution, depending on the heating time and temperature as well as the local Tb/Pd atomic ratio. These insights pave the way to the production of stable targets for heavy ion-beam irradiations as well as other applications.

Background: The direct and accurate measurement of low-level γ-emitters in samples from nuclear facilities is a challenging task due to the presence of high activities of dominant radionuclides. In this case a complex chemical separation is required to remove interfering radionuclides prior to γ-spectrometric analysis. Several radionuclides such as, 110mAg, 124,125Sb, 113Sn and 123mTe are of relevance for radioanalytical analysis in nuclear facilities. These may be readily electrodeposited at controlled-potential using flow electrolysis in aqueous solution. Here, the development and use of flow electrolysis for the pre-analytical separation of different radionuclides to suppress interferences in γ-spectrometric measurements is presented. Results: Model electrochemical systems containing inactive Ag, Sb, Sn, and Te were first characterized by voltammetry. Their separation by selective electrodeposition and stripping was evaluated with a custom-made, low-cost electrochemical flow-through cell. After optimization, the use of the flow-through cell yielded good separation procedures for stable elements at carefully chosen applied potentials. The developed electrochemical procedures were finally employed for the separation of model mixtures of radioactive tracers as well as for samples from nuclear facilities. The separation of, e.g., 110mAg or 123mTe by flow electrolysis afforded a substantial decrease of the uncertainty and the detection limits by one order of magnitude during γ-spectrometry. This allowed for a more accurate determination of low-level activity radionuclides in a sample from a nuclear facility (123mTe) as well as for the identification of others which were previously below the detection limit (103Ru, 110mAg). Significance: These results demonstrate the benefits of combining flow electrolysis with γ-spectrometry for analysis of low-level radionuclides in the presence of dominating radionuclides, and can be readily combined with other measurement techniques such as liquid scintillation counting or α-spectrometry. The presented approach not only provides a different chemical selectivity when compared to traditional separation methods, but can also be used in combination with other flow separation methods such as ion-exchange or extraction chromatography.

Carrier-free ^202Tl was thermally separated from proton-irradiated ^natHgO . Pressed ^natHgO targets were irradiated with ≈26 MeV protons at the IP2 beamline of the high-intensity proton accelerator facility at the Paul Scherrer Institute. The well-known thermal decomposition of HgO at >470 ^∘ C and the strong adsorption of Tl on a Ta surface allowed for a simple and quantitative gas-phase separation of carrier-free Tl from bulk amounts of HgO target material between 550 and 670 ^∘ °C. The separation efficiency was verified by γ -spectroscopy via the main γ -emissions of ^202Tl and co-produced ^203Hg . This method generally provides a fast and reliable preparation of carrier-free, neutron-deficient Tl radioisotopes (e.g., medically relevant ^201Tl ) from a proton-irradiated ^natHgO matrix.

Pd-Gd samples, intended as model of target materials for nuclear physics experiments, were produced via molecular plating followed by coupled reduction. Using high-resolution X-ray diffraction, performed with a highly focused X-ray beam at the Swiss Light Source, at the Paul Scherrer Institute, the formation of single intermetallic GdPd3 compounds dispersed within a Pd-Gd solid solution were identified. A homogeneous distribution of Gd was detected throughout the thickness of the samples. The micro-scale analysis provided detailed insights into the phase composition and elemental distribution, revealing that due to the low Gd concentration used, the bulk structure is likely predominantly a Pd-Gd solid solution with uniformly dispersed intermetallic domains, rather than a complete intermetallic single phase. Additionally, Gd-aggregated regions were observed at the samples surface, where µ-XPS measurements revealed the presence of Gd(III), most probably in the form of Gd2O3. This study suggests that previously reported ’intermetallic targets’ were not pure intermetallic compounds and offers design insights for future target manufacturing with similar materials. Furthermore, this study highlights the advantages of using high-resolution micro-characterization techniques.

This study investigates the evaporation and deposition of iodine from lead–bismuth eutectic (LBE) systems with iodine mole fractions of 10–5 to 10–3, crucial for the safety of LBE-cooled nuclear reactors. Combining thermosublimatography, morphological analysis and thermodynamic calculations, it identifies PbI2 and BiI3 as the two primarily deposited species, while revealing BiI disproportionation. This work provides novel insights into iodine speciation, emphasizing its importance for the safety of LBE-cooled reactors and gives input for advancing experimental setups and modeling approaches for complex nuclear systems.

The analysis of Pu isotopes with radiometric or mass spectrometry techniques requires prior chemical separation to overcome interferences from other actinides and to remove matrix components. These separations are usually carried out using extraction or ion exchange chromatography. In this work, flow electrolytic separation on anodized carbon fibers is explored as a new alternative approach for the separation and analysis of Pu isotopes by means of radiometric methods. A high-surface-area carbon fiber felt electrode was anodized and used for flow electrolytic accumulation and release of Pu. Characterization of the anodized carbon fiber felt was carried out using X-ray photoelectron and infrared spectroscopy. The conditions needed for the retention of Pu during electrolysis were investigated, optimized, and used to develop a method for the measurement of 238Pu or 239,240Pu by α-spectrometry. This method was evaluated with digested solid samples (i.e., wipe test, ceramics, and sludge) and compared with traditional chromatographic separation approaches. It was found that oxygen-containing functional groups are introduced on the carbon fiber surface upon its anodization. This allows the accumulation of Pu(IV), which is produced by adjusting the electrode potential and can be released by electroreduction to Pu(III), whereas other actinides (e.g., U, Am, and Cm) as well as matrix components are not retained. This provides a fast, single-step separation of Pu, free of impurities from reagents or resins, which may be detrimental to the preparation of α-sources. The successful measurement of Pu isotopes confirmed the reliability and good tolerance of this approach for highly complex matrices.

In the field of superheavy element chemistry, the study of the chemical properties of nihonium (Nh, Z = 113) is currently in the focus. To chemically characterize Nh, fast gas-phase chemistry experiments are essential. Hereto, a new thermochromatographic detection system named LEGEND has been developed for chemistry experiments behind the gas-filled recoil separators SHANS/SHANS2. The presented system will be further developed to higher starting point temperatures of the negative temperature gradient, thereby enabling the investigation of less volatile chemical species. A recoil transfer chamber with a vacuum window acts as an interface between the separator and the thermochromatography detector array, whereas a gas circulation and purification system ensures the required high gas purities. Finally, a state-of-the-art data acquisition system allows for event-by-event alpha-particle and spontaneous fission fragment spectroscopy. The measurement efficiency of detecting alpha-particles adsorbed on the active surface is 89.1%. Using the nuclear fusion-evaporation reactions 169 Tm( 40 Ar, x n) 204-206 Fr and 153 Eu( 40 Ar, x n) 184-185 Tl, short-lived radioisotopes 205 Fr ( t 1 /2 = 3.92 s) and 185 Tl ( t 1/2 = 1.93 s) were produced for first online experiments behind SHANS. The herein presented results render the LEGEND system suitable for gas adsorption chromatography experiments with short-lived 284 Nh ( t 1/2 approximate to 0.77 s).

The production of superheavy elements requires targets capable of withstanding prolonged, high-intensity heavy ion-beam bombardment. Current methods, such as molecular plating, produce actinoid films with insufficient stability under these conditions. To address this, a thermally superior solid solution between actinoids and Pd has been synthesized using the coupled reduction process and successfully tested. To further improve said technique, we aimed at confining Tb (i.e., a surrogate for late actinoid elements) within a thin Pd layer with a thickness of a typical target layer suitable for superheavy element synthesis. The thin Pd film was initially deposited onto a support composed of a Ni backing foil and a TiN layer intended to block the diffusion of Tb and Pd into the underlying Ni during coupled reduction. The thermal stability of the obtained multilayered samples and the diffusion behavior of Tb were studied by cross-sectional analysis via scanning electron microscopy coupled with focused ion beam milling and energy dispersive X-ray spectroscopy.

SnO 2 -based chemoresistive sensors were tested for the detection of H 2 O and CO impurities both before and after exposure to α-particles and γ-rays, assessing their radiation resistance for use in moderately radioactive environments. The materials examined were SnO 2 with gold nanoparticles, and a mix of Sn-, Ti-, and Nb-oxides. The performance was evaluated in both an open-ended gas-flow setup and in a gas-loop system. Post-irradiation characterization via scanning electron microscopy and energy-dispersive X-ray spectroscopy was performed to assess morphological changes. Preliminary results showed a fast and efficient response of the sensors after irradiation, indicating their suitability for this novel use.

The ^{244}Pu(^{50}Ti,xn)^{294-x}Lv reaction was investigated at Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. The experiment was aimed at the production of a superheavy element with Z≥114 by irradiating an actinide target with a beam heavier than ^{48}Ca. Produced Lv ions were separated from the unwanted beam and nuclear reaction products using the Berkeley Gas-filled Separator and implanted into a newly commissioned focal-plane detector system. Two decay chains were observed and assigned to the decay of ^{290}Lv. The production cross section was measured to be σ_{prod}=0.44(_{-0.28}^{+0.58})  pb at a center-of-target center-of-mass energy of 220(3) MeV. This represents the first published measurement of the production of a superheavy element near the "island of stability," with a beam of ^{50}Ti and is an essential precursor in the pursuit of searching for new elements beyond Z=118.

This study presents an in-depth analysis of the polonium evaporation from high-energy and high-intensity proton-irradiated liquid lead-bismuth eutectic. The applied experimental conditions closely mimic those encountered within an accelerator-driven nuclear reactor, particularly focusing on the interaction of other impurities with polonium. Utilizing proton-irradiated lead-bismuth eutectic with an impurity spectrum similar to that of a real reactor, this research establishes reliable data for the polonium evaporation in the presence of said impurities, employing the transpiration method. The results agree well with those of prior model experiments using pure lead-bismuth eutectic. This indicates that the other coexisting impurities have a negligible impact on the polonium evaporation. The good agreement of the experimental values with literature data emphasizes the reliability of the applied methods and the robustness of the current understanding. These findings have significant implications for the operation and safety assessment of heavy metal-cooled nuclear reactors and support the advancement of Generation IV accelerator-driven systems.

This manuscript reports on the optimization of a molecular plating procedure for the production of uniform and homogeneous films of holmium deposited onto gold-plated copper substrate. In particular, the effects caused by molecular plating solvents with different vapour pressure on the morphology and stability of the resulting films were investigated, allowing the selection of the optimum solvent. The developed procedure will allow allow the production of sources of holmium ions for the envisaged HOLMES experiment aiming at the direct measurement of the neutrino mass.

ConferenCe report questions, conflicts, and conflict resolution methods in politics and science, before highlighting the individual roles of the two in democratic decision-making processes. [2]At the core of his presentation, he highlighted two case studies that examined the position of scientific expertise during different crises: the 2008 financial crisis and the COVID-19 pandemic.Throughout, the need to acknowledge the pluralistic nature of scientific policy advice and to maintain independence and credibility as a scientist was stressed.While science provides the best available data to make a decision, it cannot provide normative claims on which decisions to take.Consequently, the role of experts in the media is fundamentally different from the role of experts in policy advice.Overall, this contribution underscored the complexity of science-policy dynamics, emphasized the importance of effective communication, and highlighted the pluralistic character of scientific policy advice in democratic decision-making.To complement this perspective on how scientists, as individuals, can interface with policymakers, Nineta Hrastelj (Secretary General of the European Chemical Society, EuChemS) addressed the question of how science can contribute to policymaking.Drawing from her experience in science policy making [3] with a strong academic background, she underlined the need for scientists to develop additional skills beyond their scientific expertise.For example, skills that politicians are readily trained in, but scientists largely lack, include negotiation, rhetoric, communication with/in public and media domains, as well as advanced presentation skills.Consequently, the first step for any scientist aspiring to work in the policy sphere should be to obtain these skills, both through training courses and also through practice.Dr. Hrastelj presented the structure of the European policy landscape, highlighting the importance of understanding the regulations, directives, as well as the frameworks and dynamics of European institutions (e.g. the European Commission, the European Parliament, and the Council of the EU).More precisely, she provided examples of EuChemS' involvement in policy calls and stakeholder engagements.Suggested opportunities for scientists to engage in policy-making included the registration as experts in their respective fields, participating in expert groups, and contributing to public consultations. [4] Dr. Hrastelj ended with an appeal to scientists to actively contribute to policy-making and thereby help to shape decisions through scientific evidence and expertise.Ultimately, scientists should (and must) provide trustworthy and unbiased scientific evidence to policymakers.The final decision made by the lawmakers, however, is out of the scientists' hands.

During recent online gas-phase experiments with the transactinide elements copernicium (Cn, Z = 112) and flerovium (Fl, Z = 114), the transport of a volatile astatine species was observed. Comprehensive Monte Carlo simulations of the deposition pattern of At-211 on the given quartz, selenium, and gold chromatographic surfaces were carried out, and the corresponding adsorption enthalpies were estimated. Based on the astatine speciation from previous model experiments, the compound observed in this work was ascribed to AtOH/HAtO. The herein presented results assist in paving the way toward a future chemical characterization of tennessine (Ts, Z = 117) with similar gas adsorption chromatography techniques.

The Swiss Spallation Neutron Source SINQ of the Paul Scherrer Institute provides neutrons via proton-induced spallation reactions in a lead target. Produced neutrons are thermalized and impinge on 235U-targets, enclosed in a three-part chamber assembly, which is located in the inner wall of the SINQ shielding. The thermal-neutron-induced fission products can be readily transported from this chamber assembly to a radiochemical laboratory using the gas-jet technique either with a pure carrier gas or with an aerosol-particle-loaded carrier gas. In the past, mainly radioisotopes of the elements Se, Br, Rb, and Kr were retrieved and used for gas-phase chemistry experiments. Here, we present first experiments after the commissioning of the SINQ gas-jet facility as a source of recoverable, non-volatile and volatile, carrier-free fission products for general radiochemical studies and other applications.