Radionuclide Research Articles

Spectroscopic analysis of alpha particles from radioactive nuclides with CR-39 plastic nuclear track detectors

Abstract A spectroscopy method of alpha particles with the track geometry parameters in CR-39 plastic nuclear track detectors is proposed. The relationship between the track registration sensitivity and incident angle of each etch pit is analyzed. The components of alpha particles emitted from radon, thoron and 241Am can be roughly separated when the etching level is not exceeded beyond the range in CR-39. This work aims at improving the dose assessment accuracy from exposure to indoor radon and thoron.

What work does ‘contamination’ do? An agential realist account of oil wastewater and radium in groundwater

Oil wastewater often contains high levels of radium, a carcinogenic and radioactive element. This article closely engages with two investigations of radium in groundwater downstream from oil wastewater storage pits. While one investigation found that radium did not travel beyond the storage pits, the other found evidence of elevated radium some two kilometers downstream. With an agential realist analysis, we resolve these differences, showing that these two experimental apparatuses defined and mobilized two different phenomena of radium, and of radium-as-contaminant. What geologists call ‘rock-water interactions’ are materially meaningful intra-actions. Far from being a mere philosophical gloss on otherwise conventional science, the ‘intra-’ signifies that, in these processes, the sediment and the groundwater are bringing each other into being. Groundwater sampling entails a specific set of intra-actions with the subsurface that enact different agential cuts. In addition, a geochemical focus on objects, rather than relations, also constrains understandings of chemical harm and accountability. These concepts do not only affect experimental apparatuses; rather, they come into being through and with each other. Therefore, rigorous approaches to groundwater and remediation do not lie in the pull to reify individual groundwater constituents, or to arbitrate between ‘contaminant’ and ‘contaminated’. Rather, rigorous approaches lie in the role of chemical relations in constituting specific groundwater phenomena. We elaborate three aspects of these relations: the constitution of radium-as-isolated-element through the ontological work of sampling schema, the formation of scale and attendant spacetimematterings within experimental apparatuses, and the work of contamination logics within conceptualizations of chemical harm. This analysis has major implications for understanding the potential harm of oil wastewater to groundwater.

Assessment of Groundwater Quality in the Semi-Arid Environment: Implications of Climate Change

The hydrogeochemical properties and evolution of groundwater in the Essaouira syncline basin in northwestern Morocco were investigated in this study, with a total of 447 samples during different campaigns (April 2017, May 2018, March 2019, and July 2020). These samples were analyzed for major ions and stable and radioactive water isotopes (δ2H, δ18O, and 3H). With decreasing rainfall from climate change in Morocco, it is crucial to assess the sustainability of groundwater reserves. This shortage leads to the degradation of water and soil quality. To ensure sustainable water management and preserve the environment in the study area, it is necessary to assess groundwater quality for drinking and irrigation, take precautions, and establish management plans. This study assessed groundwater quality using two water quality index methods (WQI and IWQI). Several natural processes control groundwater mineralization, including the dissolution of evaporite and carbonate minerals, cation exchange phenomena, evaporation, and seawater intrusion. According to the results obtained using the WQI method, all groundwater samples in the study area are generally of poor quality and must be treated before being used for domestic purposes. Based on the results obtained by the IWQI method, the samples are suitable for use as irrigation water, especially for plants resistant to high salinity concentrations. Stable isotope measurements (δ2H and δ18O) indicate that Atlantic precipitation continuously recharges the recharge areas of the Essaouira Basin. Thus, the low values of tritium (3H) in groundwater mean that the freshwater in the Essaouira Basin is ancient.

Assessment of Natural Radioactive Nuclides in Different Herbal Remedies Consumed in Katsina Metropolis

The use of herbal remedies to treat various ailments is common practice in developing countries, but the formulation of these products is usually complex, hence, the need for thorough quality checks especially with possible health risks these could pose. The research aimed to assess the natural radioactive nuclides concentrations of herbal formulations sold in Katsina Metropolis and ascertain the radiological implications for humans. The activity concentration of natural radionuclides in the fifteen (15) herbal remedies commonly consumed in the Katsina metropolis. Results from the above table show the activity of natural radionuclides in 15 herbal remedy samples found in the Katsina metropolis. The activity concentration of 40K ranges from 1027.76+51.30, which was found to have the highest radioactivity in the G, and 51.77+2.60 was found to be lowest in K. In 238U which ranges from 72.78+7.67 in O and the lowest concentration of 1.65+0.23 in E then lastly followed by the activity concentration of 232Th activity concentration varies from 20.18+1.13 as the highest and the lowest in B with 1.26+-0.07.

Current status of the ISOL beamline and recent advances in radioactive isotope extraction experiments

Current status of the ISOL beamline and recent advances in radioactive isotope extraction experiments

Hazard, risk, reliability assessment and improvement of Darlington Tritium Removal Facility (DTRF) cryogenic refrigeration system

Tritium is a radioactive isotope of hydrogen, produced in heavy water, during CANDU reactor operations by neutron absorption. The tritium removal facility at Darlington (DTRF) is used to extract tritium from the heavy water on a continuous basis and concentrates it in preparation for immobilization and storage. There are several internal and external hazards associated with the operation of DTRF, such as fires, onsite transportation accidents, exposure to radioactive materials, explosion due to Hydrogen (H2) and the release of radioactive substances from the Tritium Immobilization System. This paper conducts a risk analysis for the DTRF Cryogenic Refrigeration System, associated with both Low and High Tritium Distillation columns. This study includes hazard identification, consequence analysis and risk estimation. Fault Tree and Event Tree Analysis conducted, system reliability, availability and human reliability was considered. Consequently, methods for risk reduction and integration with improvement to CRS design is discussed.

Influence of the gamma source on the radiolytic stability of N,N,N′,N′-tetra-n-octyl-diglycolamide (TODGA)

Abstract In nuclear reprocessing, hydrolytic and radiolytic stability of ligands, extractants, diluents and solvents is of particular importance. The strength of extraction systems can only be fully exploited when process conditions are predictable and essential molecules, which are in close proximity to radioactive isotopes, are resistant to the radiation. During the development of novel extraction systems, testing of the radiolytic stability is often evaluated by exposing the molecules to high energetic gamma rays. In this work, the influence of the source of gamma rays is evaluated. TODGA was irradiated from 0–500 kGy using different sources of gamma rays, and its degradation was followed using UPLC-HRMS. Pool-type gamma irradiation facilities BRIGITTE B (Co-60) and GEUSE II (spent nuclear fuel) at SCK CEN were employed to serve as gamma sources. In this work, it is found that there is no significant influence on TODGA degradation which can be attributed to the origin of the gamma source.

Scientific Insights into the Quantum Dots (QDs)-Based Electrochemical Sensors for State-of-the-Art Applications.

Size-dependent optical and electronic properties are unique characteristics of quantum dots (QDs). A significant advantage is the quantum confinement effect that allows their precise tuning to achieve required characteristics and behavior for the targeted applications. Regarding the aforementioned factors, QDs-based sensors have exhibited dramatic potential for the diverse and advanced applications. For example, QDs-based devices have been potentially utilized for bioimaging, drug delivery, cancer therapy, and environmental remediation. In recent years, use of QDs-based electrochemical sensors have been further extended in other areas like gas sensing, metal ion detection, monitoring of organic pollutants, and detection of radioactive isotopes. Objective of this study is to rationalize the QDs-based electrochemical sensors for state-of-the-art applications. This review article comprehensively illustrates the importance of aforementioned devices along with sources from which QDs devices have been formulated and fabricated. Other distinct features of QDs devices are associated with their extremely high active surfaces, inherent ability of reproducibility, sensitivity, and selectivity for the targeted analyte detection. In this review, major categories of QD materials along with justification of their key roles in electrochemical devices have been demonstrated and discussed. All categories have been evaluated with special emphasis on the advantages and drawbacks/challenges associated with QD materials. However, in the interests of readers and researchers, recent improvements also have been included and discussed. On the evaluation, it has been concluded that despite significant challenges, QDs-based electrochemical sensors exhibit excellent performances for state-of-the-art and targeted applications.

Induced polarization of clay-rich materials. 4. Water content and temperature effects in bentonites

Deep geological disposals (DGDs) are widely seen to be the best solution to contain high-level radioactive wastes safely. Compacted bentonite and bentonite-sand mixtures are considered the most appropriate buffers or sealing materials for access drifts, ramps, and shafts due to their favorable physicochemical and hydro-mechanical properties. Bentonite-sand mixtures are expected to swell and seal all voids when in contact with water, forming an impermeable barrier to radioactive elements. The parameters that will most affect the hydraulic performance of these seals are their water content, dry density, water salinity, and temperature. Monitoring and assessing these parameters are, therefore, crucial to confirm that the seals’ safety functions are fulfilled during the life of a DGD. Induced polarization (IP) is a nonintrusive geophysical method able to perform this task. However, the underlying physics of bentonite sand mixtures has not been checked. The complex conductivity spectra of 42 compacted bentonite-sand mixtures were measured in the frequency range of 1 Hz–45 kHz in order to develop workable relationships between in-phase and quadrature conductivities versus water content and saturation, pore water conductivity, bentonite-sand ratio (10% to 100%), temperature (10°C–60°C), and dry density (0.97 to 1.64 g cm−3). We observe that conductivity is mostly dominated by surface conductivity associated with the Stern layer (SL) coating the surface of smectite, the main component of bentonite. At a given salinity and temperature, the in-phase and quadrature conductivities obey the power law relationships with water content and saturation. The in-phase and quadrature conductivities depend on the temperature according to a classical linear relationship with the same temperature coefficient. An SL-based model is used to explain the dependence of the complex conductivity with water content, dry density, water salinity, and temperature. It could be used to interpret the IP field data to monitor the efficiency of the seal of DGD facilities.

Effect of temperature on the scintillation properties of pure LaCl3 and Cs2LiYCl6:Ce crystals for neutron spectroscopy

Abstract The Lunar Vehicle Radiation Dosimeters (LVRAD) project, run by the Korea Astronomy and Space Science Institute, is currently in the detector R&D phase. Its mission is to measure the radiation exposure experienced by astronauts on the lunar surface and to search for water and radioactive isotopes. This study focuses on inorganic scintillator R&D for neutron spectroscopy, which is essential for the LVRAD project. Two candidates, pure LaCl3 and Cs2LiYCl6:Ce enriched with 95% 6Li (CLYC-6) detectors, were investigated in this work. Though their neutron spectroscopy performance meets radiation hardness requirements, the temperature-dependent performance of the detectors needs to be clearly understood to ensure reliable operation in space. Therefore, the performance of pure LaCl3 and CLYC-6 detectors was investigated for working temperatures ranging from -30∘C to +50∘C. The dimensions of the scintillators used for measurements were Φ1.5 inch × 1.0 inch for pure LaCl3 and Φ1.5 inch × 1.5 inches for CLYC-6. Scintillation performance was measured using a Hamamatsu H7195 photomultiplier tube with a 500 MHz flash analog-to-digital converter. The detectors were operated in a large temperature and humidity chamber across a temperature range from -30∘C to +50∘C, and the temperature dependence of the pulse shape discrimination performance for fast and thermal neutrons was measured using pure LaCl3 and CLYC-6, respectively. The effect of the temperature on the absolute light yield, energy resolution, and decay times was also measured. Based on the results, the pure LaCl3 and CLYC-6 detectors proved suitable for neutron spectroscopy for the LVRAD project.

Full radionuclide analysis of polymetallic nodules from the Clarion-Clipperton-Fracture Zone in the NE Pacific

Polymetallic Nodules from the deep sea are currently being targeted for mineral exploration as they are a significant resource for various critical metals. In addition to accumulating such metals, nodules are also known to adsorb naturally occurring radioactive nuclides. With the possibility of exploitation of nodules becoming more likely within the next years, it is important to assess the potential radiation exposures resulting from the handling of polymetallic nodules. In this study we present, for the first time, specific activities of all long-lived alpha, beta and gamma emitters from the natural decay chains of Uranium-238, Uranium-235 and Thorium-232, in bulk and surface material of the same nodules obtained from 10 locations within the Clarion-Clipperton Zone. The results show elevated specific activities for the nuclides Th-230, Ra-226, Pb-210, Po-210, as well as Pa-231 and Ac-227 in accordance with prior reported activities. However, in contrast to assumptions made in previous studies, our analyses show that Pa-231 is not in equilibrium with its daughter nuclide Ac-227. The emanation factor of Rn-222 for dry and water-saturated nodules has also been determined and is higher than previously reported. The results presented here are a key ingredient to assess human radiation exposure during the processes of polymetallic nodule mining, storage and beneficiation.

UK patients face imaging cancellations amid shortage of radioactive isotope.

UK patients face imaging cancellations amid shortage of radioactive isotope.

Uranium in groundwaters of North Kazakhstan

Relevance. The need to dentify the characteristics of the distribution of radioactive elements in the groundwater of Northern Kazakhstan. Aim. Generalization of available data on the geochemistry of groundwater and uranium and radon distribution in them using the example of the northern regions of the Republic of Kazakhstan. Methods. Generalization of long-term hydrogeochemical research and compilation of an electronic data bank on the territory of Northern Kazakhstan. A laboratory study of the chemical composition of groundwater was carried out at the Research Laboratory of Hydrogeochemistry of the School of Natural Resources Engineering of Tomsk Polytechnic University. Measurements of 222Rn contents in waters were carried out using the Alfarad Plus complex in the Laboratory of Hydrogeology of Sedimentary Basins of Siberia, Institute of Geology and Geography, Siberian Branch, Russian Academy of Sciences. Results. The groundwater of aquifers of different ages, distributed in the territory of Northern Kazakhstan (North Kazakhstan uranium province), was studied. Two geochemical sets of groundwater were identified. The first is characterized by the dominance of HCO3– and Mg2+ in the water composition, and the second by Cl– and Na+. A change in composition and an increase in the value of total mineralization from 0,1 to 49 g/dm3, in the direction from north to south, indicate the development of continental salinization. In natural waters of the first group, uranium content varies from 0.065 to 16000 μg/dm3 and radon activity from 4 to 3885 Bq/dm3. For sodium chloride waters of the second set, concentrations can reach 32500 μg/dm3, and radon activity is 6–59 Bq/dm3, since the emanating reservoir (granitoids) is located to the north – at a distance of 80–100 km. Naturally, granitoid massifs of the studied region are sources of uranium. Their drainage by the river network leads to its removal and concentration on geochemical barriers in the groundwater of the Neogene-Quaternary aquifer. This distribution of radioactive elements is associated with the high migration ability of uranium in solution in the form of uranyl ion in oxidizing geochemical conditions.

Thorium Recovery with Crown Ether–Polymer Composite Membranes

Thorium is a weak radioactive element, but the control of its concentration in natural aqueous systems is of great interest for health, because it is a toxic heavy metal. The present paper presents the recovery of thorium from diluted synthetic aqueous systems by nanofiltration. The membranes used for the nanofiltration of systems containing thorium species are composites containing 4′-Aminobenzo-15-crown-5 ether (ABCE) and sulfonated poly–etherether–ketone (sPEEK). The composite membranes (ABCE–sPEEK) were characterized by scanning electron microscopy (SEM), energy-dispersive X–Ray spectroscopy (EDAX), thermal analysis (TG and DSC), and from the perspective of thorium removal performance. To determine the process performance, the variables were the following: the nature of the composite membrane, the concentration of thorium in the aqueous systems, the rotation speed of the stirrer, and the pressure and the pH of the thorium aqueous system. When using pure water, a permeate flux value of 12 L·m−2 h−1 was obtained for the sPEEK membrane, and a permeate flux value of up to 15 L·m−2 h−1 was obtained for the ABCE–sPEEK composite membrane. The use of mechanical stirring, with a propeller stirrer, lead to an increase in the permeate flux value of pure water by about 20% for each of the studied membranes. Depending on the concentration of thorium and the pH of the feed solution, retentions between 84.9% and 98.4% were obtained. An important observation was the retention jump at pH 2 for the ABCE–sPEEK composite membrane. In the paper, a thorium ion retention mechanism is proposed for the sPEEK membrane and the ABCE–sPEEK composite membrane.

Assessment of radioactive nuclides and heavy metals in soil and drink water in Lahij city, Yemen

This study was conducted in Lahij city, Yemen, to evaluate the concentrations and potential health risks of natural radioactive nuclides and heavy metals in soil and drinking water. A total of 21 soil samples and 17 water samples were collected from various locations. A high-purity germanium gamma detector HPGe was used to measure the concentrations of 40K, 232Th, and 226Ra in all samples, along with the concentrations of heavy metals. In soil samples, the average concentrations of 40K, 232Th, and 226Ra were 731.5, 30.7, and 28.16 Bq kg−1, respectively. While some samples showed higher than permissible levels for 226Ra and 232Th, the overall average remained within acceptable limits. However, 40K levels were almost twice the recommended global limits. In water samples, the average concentrations of these nuclides were 5.38, 0.73, and 0.66 Bq L−1, all within the global safety limits. Radiological risk assessments for soil indicated an average radium equivalent activity (Raeq) of 124.4 Bq kg−1, absorbed dose rate in air of 59.9 nGy h−1, annual effective dose rate of 0.07 mSv y−1, outdoor excess lifetime cancer risk (ELCR) of 0.26 × 10−3, and annual gonad equivalent dose (AGED) of 336.6 mSv y−1. Risk indices, including the activity concentration index (Iγ), external hazard index (Hex), and internal hazard index (Hin), averaged 0.48, 0.34, and 0.41, respectively, all below global limits except for AGED, which slightly exceeded the recommended level. For drinking water, the total ingestion dose was calculated for different age groups. The average doses for infants, children, and adults were 0.15, 0.27, and 0.19 mSv y−1, respectively. The doses for children and adults exceeded the permissible limits, while those for infants were within safe levels. Heavy metal concentrations were measured in all samples, and the Hazard Quotient (HQ) was calculated. In soil samples, HQ values for all metals >1, indicating potential health risks. In water samples, HQ values were also >1 for all metals except vanadium (V) and iron (Fe). To reduce the dangers associated with radioactive nuclides and heavy metals, regular monitoring and cleanup are crucial, and further research is needed to understand contamination sources and long-term health impacts.

Mathematical Modeling Unveils Optimization Strategies for Targeted Radionuclide Therapy of Blood Cancers.

Targeted radionuclide therapy is based on injections of cancer-specific molecules conjugated with radioactive nuclides. Despite the specificity of this treatment, it is not devoid of side-effects limiting its use and is especially harmful for rapidly proliferating organs well perfused by blood, like bone marrow. Optimization of radioconjugates administration accounting for toxicity constraints can increase treatment efficacy. Based on our experiments on disseminated multiple myeloma mouse model treated by 225Ac-DOTA-daratumumab, we developed a mathematical model which investigation highlighted the following principles for optimization of targeted radionuclide therapy. 1) Nuclide to antibody ratio importance. The density of radioconjugates on cancer cells determines the density of radiation energy deposited in them. Low labeling ratio as well as accumulation of unlabeled antibodies and antibodies attached to decay products in the bloodstream can mitigate cancer radiation damage due to excessive occupation of specific receptors by antibodies devoid of radioactive nuclides. 2) Cancer binding capacity-based dosing. The total number of specific receptors on cancer cells is a critical factor for treatment optimization, which estimation may allow increasing treatment efficacy close to its theoretical limit. Injection of doses significantly exceeding cancer binding capacity should be avoided since radioconjugates remaining in the bloodstream have negligible efficacy to toxicity ratio. 3) Particle range-guided multi-dosing. The use of short-range particle emitters and high-affinity antibodies can allow for robust treatment optimization via initial saturation of cancer binding capacity, enabling redistribution of further injected radioconjugates and deposited dose towards still viable cells that continue expressing specific receptors.

Synthesis and characterization of multi-component borosilicate glass beads for radioactive liquid waste immobilisation

High-level radioactive liquid waste (HLW) is immobilized in a glass matrix through a process called vitrification. In this process, HLW and glass-forming oxides are combined in a pre-determined ratio within a glass melter to produce a vitrified waste form. The properties of this waste form, including its ability to accommodate different radioactive isotopes, depend on the composition of the base glass.In the present study, multi-component amorphous borosilicate-based glasses (SiO2-B2O3-Na2O-TiO2-Fe2O3-CaO-K2O) in bead form (diameter 2–3 mm) were developed. The elemental composition of the glass beads (GBs) was analyzed using an optical emission spectrometer. Additionally, the GBs underwent various physico-chemical analyses, including functional group identification, thermal, electrical, and mechanical properties, as well as viscosity and chemical durability assessments, to identify the optimal glass compositions. The influence of Na2O on the pouring temperature was also examined. Crushing strength and attrition rate measurements were conducted to confirm the suitability of GBs for remote feeding into the melter. The GBs developed in the study are unique, with significant potential for worldwide use in vitrification facilities, particularly in continuous vitrification systems employing Joule Heated Ceramic Melter (JHCM) technology.

Separation of radioactive isotope 227Ac from LaBr3 via vacuum evaporation for low-background scintillating detectors

Both radioactive isotopes 138La and 227Ac in LaBr3:Ce crystal typically produce considerable intrinsic background signals, and thus hinder their applications with low count rates. Since the complete separation of 138La is almost impossible, the contamination of 138La is stubbornly present in all La-halide based scintillators. In this study, an efficient purification protocol based on vacuum distillation was developed to separate 227Ac from feedstock and reduce intrinsic background signal at 1.6–3 MeV introduced by 227Ac in LaBr3:Ce crystals. Through combined theoretical and experimental analysis, the alpha contamination from 227Ac in LaBr3: Ce was reduced exploiting the different evaporation behaviors of LaBr3 and AcBr3. Additional impurities were also reduced to lower levels, as confirmed by glow discharge mass spectrometry (GDMS). The purified material, distilled at various temperatures (1203 K, 1253 K, and 1303 K), was used to grow LaBr3:Ce single crystals for performance evaluation. The crystals distilled at 1203 K demonstrated enhanced scintillation performance, featuring lower background counts (0.0181 counts·s−1·cm−3 @1.6–3 MeV) by approximately 50%–60 % of untreated sample and excellent energy resolution (2.47 %@662 KeV). This study presents an effective approach for preparing low-background lanthanum bromide, so as to offer valuable insights for isotope separation in scintillation crystals by vacuum distillation.

Trace element partitioning between natural barite and deep anoxic groundwaters: Implications for radionuclide retention in host rocks of nuclear waste repositories

Safety assessments for deep geological repositories involve risk calculations for the release of radionuclides like Ra, U, Pu and trivalent actinides from the storage containers to the groundwater. The retention of radionuclides through water-mineral interaction along the groundwater flow path could be a crucial factor in case of a repository failure. Barite (BaSO4) assumes significance in this context, as it has the potential to (re)crystallize and incorporate significant quantities of radioactive elements under relevant physico-chemical conditions.The assessment of mineral-fluid partition coefficients provides a means to evaluate the uptake potential of elements into the mineral. Usually, partition coefficients are determined under well-defined and controlled experimental conditions in laboratories. However, these results have shown discrepancies to partitioning coefficients determined from natural systems.Furthermore, effects like diagenesis or changes in the chemical fluid parameters might lead to a secondary alteration of the phases and affecting the retention ability.Here we investigate the incorporation of trace elements in natural barite from a borehole at 415 m depth in the Äspö Hard Rock Laboratory (Sweden). High-resolution LA-ICP-MS enables the quantitative determination of field-based partition coefficients through the integrated pixel average of selected zones in element distribution maps, combined with existing fluid concentration data. Similarities between the solid solution systems (Ra,Ba)SO4 and (Sr,Ba)SO4 allowed the combination of Sr partitioning data with density-functional theory simulations for an estimation of the partition coefficient value for Ra in natural barite. Values in the 10−2 range were determined, showing a deviation from those reported in previous experimental studies in the 10° range.Moreover, lanthanum serves as an analogue element for the radioactive trivalent actinides. The partition coefficient values for La in natural barite were determined in the range of 10−2 and 10−1, aligning well with experimental partition coefficients. Although density functional theory simulations cannot directly convert a La partition coefficient into a partition coefficient for trivalent actinides, it is assumed that these elements exhibit comparable behavior. Besides primary growth zonation, La also exhibits strong secondary enrichment, probably resulting from groundwater mixing and late fluid-mediated element transport through connected intracrystalline pore space oriented at cleavage plane systems. Additional SIMS analysis provides insights into the temporal variation of the sulfate source at the sampling site reflecting the influence of different waters during mineral growth.This study demonstrates a discrepancy between natural and synthetic PRa for barite and emphasizes that secondary processes significantly impact radionuclide retention in barite. Including these effects in reactive transport models will improve the reliability and applicability of integrative risk models.

U and Th zonation in apatite observed by synchrotron X-ray fluorescence tomography and implications for the (U–Th) ∕ He system

Abstract. Synchrotron X-ray fluorescence microtomography can non-destructively image the three-dimensional distribution of several trace elements in whole apatite crystals at the resolution of 1 µm3. This allows for precise determination of the physical geometry of a crystal and the quantification of the relative abundance of the radioactive parent nuclides uranium and thorium with high fidelity. We use these data to develop a more precise alpha ejection correction for (U–Th) / He thermochronology and high-resolution models of apatite crystals that are the foundation for a new generation of three-dimensional diffusion modeling. The application of synchrotron radiation to non-destructive imaging of minerals used for geochronology sheds light on causes of long-standing unresolved problems in the field that are rooted in previously unmeasurable parent nuclide zonation, especially the pervasive overdispersion of single-crystal ages.