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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Comets and carbonaceous chondrites delivered noble gases to the Moon

Trapped xenon isotopes in two Apollo 17 mare basalt fragments are similar to those in primitive meteorites. Xenon would have been effectively excluded from the Moon in the aftermath of its formation in a giant impact. As such, lunar mantle xenon trapped in the mare basalts is best explained as being derived from late accretion occurring before or concurrent with the formation of the lunar crust. Here, the isotopic composition indicates that a combination of comets and carbonaceous chondrites delivered this xenon to the lunar mantle. The inferred mass of accreted cometary ice would have delivered significantly less than a part per million of water to the lunar mantle. The inferred mass of accreted carbonaceous chondrites would have supplied at least a half of a part per million of water. The data further indicate that enstatite chondrites are unlikely to have supplied the majority of late accreted mass.

Chemistry↗
DOE OSTI2024

Measurements of radioxenon activities during periods of gaseous release from an advanced gas-cooled reactor

Activities of radioxenon isotopes are reported from an Advanced Gas-cooled Reactor (AGR) during periods of gaseous release. Xenon isotopes are relevant to the monitoring regime of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). These releases may affect detections from the International Monitoring System (IMS) by influencing the radioxenon background. Time series activity plots have been produced from both in-core monitoring and direct measurement at the point of release using a stack monitor system. Ratio plots using both data sets have been produced with results compared with a commonly chosen nuclear explosion “discrimination line.” The reported results improve the understanding of radionuclide emissions from civil nuclear power plants. This work is being performed as part of the Xenon Environmental Nuclide Analysis at Hartlepool (XENAH) collaboration between the Atomic Weapons Establishment (AWE, UK), EDF Energy (UK), Pacific Northwest National Laboratory (PNNL, USA), and the Swedish Defence Research Agency (FOI).

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

Fission gas trapped in Chornobyl fuel microparticles reveals details of reactor operations

The isotopic ratios of fission gas would provide important source information of a nuclear fuel sample found in the environment. However, it is believed that during a reactor accident like Chornobyl all fission gas is lost and that the radioactive particles found in the Chornobyl Exclusion Zone today are depleted in gases by the initial explosion and subsequent fire. We disprove this hypothesis by detection and analysis of trapped krypton and xenon in these particles. Our analysis of krypton and xenon isotopes by noble gas mass spectroscopy in combination with resonance ionization mass spectrometry establishes that important information about reactor operations like age, neutron flux and plutonium fission fraction can still be reconstructed from individual micrometer-sized particles even after decades of weathering in the environment.

Chornobyl↗
DOE OSTI2025

Detecting 127 Xe in an atmospheric tracer experiment

The Xcounts algorithm for calculating air concentrations of radioactive xenon isotopes (Eslinger et al., 2023) has been extended to estimate 127 Xe in addition to 131m Xe, 133m Xe, 133 Xe, and 135 Xe. The algorithm was applied to 119 samples collected with a SAUNA Q B system (Ringbom et al., 2023) during a two-month atmospheric tracer release experiment. Finally, the algorithm identified two samples with 127 Xe present from a single 1.5 h release about 3.5 km upwind of the sampler and no false detections of 127 Xe were observed in the other samples.

127Xe calibration↗
DOE OSTI2025

Glass-Bonded Monazite Waste Forms for Lanthanide and Actinide Immobilization: From Theoretical Design to Scale-Up Production and Characterization

The development of nuclear waste forms for both existing and future nuclear wastes is critical to ensuring global environmental safety. This study focuses on waste management from molten salt reactors, where fuel exists in a salt form and could be processed in real time for the removal of neutron poisons such as xenon isotopes (e.g., 135 Xe) and rare earth elements (REEs, e.g., 149 Sm). To ensure safe, stable, and long-term disposal in geological repositories, REEs must be incorporated into a durable waste form. Iron-phosphate glasses are a promising candidate due to their low melting points, high chemical durability, and their ability to incorporate high concentrations of REEs. In this study, we successfully prepared iron-phosphate glass waste forms with high Nd loadings (up to 37 mass %) in batch sizes ranging from small (23 g) to large (1600 g). The resulting materials contained up to 75 mass % NdPO 4 , contributing to their mechanical resilience and exceptional chemical durability. These findings highlight the potential of iron-phosphate glasses as high-efficiency, chemically durable waste forms and demonstrate the successful transition from theoretical design to scaled-up production.

amorphous materials↗
DOE OSTI2026

Direct observation of the superallowed α-decay of 104 Te

The radioactivity of the α particle is among the most compelling evidence for the existence of cluster structures in atomic nuclei. During the decay process, a pre-existing α particle tunnels through the potential barrier formed by the residual nucleus1,2. The degree of preformation of the α particle, a strongly bound system of two protons and two neutrons, is extracted from the data by dividing the α-decay probability by the barrier penetrability for a given particle energy. The preformation probability changes rapidly near nuclear shell closures, which is direct evidence that clustering is connected to nuclear structure3. Enhanced preformation was observed in the lightest α-particle emitters, spherical tellurium and xenon isotopes decaying to magic isotopes of tin. Here we show the most extreme case of α-particle preformation from the measurement of the decay of tellurium-104 (104Te). With a half-life of , 104Te is the fastest ground-state α-emitting nucleus known so far. The deduced preformation demonstrates that the enhancement is greater for 104Te than for any other nucleus. One nuclear model that can explain our observation postulates that the α particle can exist only in the low-nuclear-matter-density regions on the surface of the nucleus. The uniquely high preformation for 104Te is attributed to its relation to doubly magic tin-100 (100Sn), creating conditions conducive to form an α particle.

Cox, Ian↗
DOE OSTI2024

Vacuum-ultraviolet light source for enhanced production of metastable krypton and xenon beams

Here, we demonstrate excitation of metastable krypton and xenon beams using a vacuum ultraviolet lamp and directly compare the performance of this method to metastable excitation based on a radio-frequency-driven plasma discharge. In our apparatus, lamp-based metastable excitation outperforms the plasma discharge across a wide range of beam flux values relevant for atom trap trace analysis (ATTA). Moreover, we do not observe significant degradation in lamp performance after over 160 h of operation. We find that lamp-based excitation is particularly advantageous at the smallest and largest beam fluxes tested, demonstrating the utility of this approach both for improving krypton ATTA and for enabling the detection of radioactive xenon isotopes using ATTA. Finally, we demonstrate an additional enhancement to lamp-based metastable excitation efficiency and stability by applying an external magnetic field.

Metastable noble gases↗
DOE OSTI2025

A statistical approach to screening isotopic signatures in monitoring for underground nuclear explosions

The ability to differentiate between atmospheric radionuclide signatures from underground nuclear explosions (UNEs) and signals from other sources, such as medical isotope-production facilities and nuclear reactors, can be critical to the detection and monitoring of unannounced, low-yield nuclear events. Signatures having anomalously high amplitudes, compared to background levels, remain the best indicator in screening for a UNE. However, isotopic composition can further validate a suspected UNE signature, but separation from any atmospheric background composition is first necessary. To date, evaluating the challenges of performing this separation has typically involved comparing an observed background with a highly idealized deterministic model of radioxenon signature production by a UNE that does not consider the influence of post-detonation chemical/physical processes in the detonation cavity or the subsequent gas transport mechanisms that can also affect the isotopic composition of the detected gas signature. In addition, purely deterministic models, as previously employed, overlook the uncertainty inherent in estimating critical parameters characterizing the UNE and its detonation environment. In this paper, we create detailed, multi-parameter models of radionuclide evolution using the widely accepted England and Rider post-detonation radionuclide decay-chain network coupled to detailed models simulating physical production and transport processes affecting the gas signature. Because these models are governed by uncertain parameters including barometric fluctuations, realistic ranges of variation for each of the parameters influencing isotopic composition are then defined. A Latin-Hypercube sampling approach is used to obtain a random distribution of isotopic production and gas transport results associated with a given value of each parameter. We apply these results to background histories of two stations, one providing 4-isotope background measurements and the other providing two-isotope measurements associated with the 2013 DPRK announced UNE.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2025

Adsorption Studies of Dilute Krypton and Xenon from Nitrogen on SBMOF-1 and Activated Charcoal for Applications in Isotope Harvesting

Adsorptive partitioning of dilute krypton (Kr) and xenon (Xe) onto Stony Brook Metal–Organic Framework (SBMOF-1) and activated charcoal (AC) from carrier nitrogen was experimentally measured at temperatures ranging from 195 to 293 K. For this purpose, a closed-loop system for gas adsorption experiments was developed. From the Kr adsorption measurements, the adsorption equilibrium constant for Kr on SBMOF-1 was calculated, yielding a value for the enthalpy of adsorption of −19 ± 1 kJ·mol –1 . The partition coefficients were utilized to estimate the extraction rates of 76 Kr, 77 Kr, and 122 Xe isotopes during isotope harvesting at the Facility for Rare Isotope Beams (FRIB). We conclude that both materials showed promising results for the extraction of noble gases from FRIB effluents using temperature swing adsorption.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

FGMS-poster

Idaho National Laboratory (INL) performs post irradiation examination (PIE) of tri-structural isotropic (TRISO)-coated particle fuel to help qualify it for high temperature gas cooled reactors. TRISO fuel compacts are re-irradiated in the Neutron Radiography Reactor (NRAD) to generate the short lived fission products needed for fission product release testing. The Fuel Accident Condition Simulator (FACS) furnace and newly added Screen Neutron Irradiated Fuel for Failure (SNIFF) furnace heat the compacts in helium to temperatures of up to 2,000°C, prompting fission product release—predominantly gaseous xenon and krypton isotopes and condensable products such as cesium—from failed particles. These released isotopes are transported to a fission gas monitoring system (FGMS 1 or FGMS 3), where they accumulate in cryogenic cold traps and are quantified using high-purity germanium (HPGe) detectors. The addition of SNIFF and FGMS 3 increases throughput by enabling simultaneous testing of multiple compacts. Furthermore, automated INL developed software provides continuous, near-real time monitoring of fission product inventories and manages the liquid nitrogen cooling of the traps. These system enhancements improve the efficiency, data quality, and testing capacity of TRISO fuel performance evaluations.

07 - ISOTOPES AND RADIATION SOURCES↗
DOE OSTI2024

Supernova electron-neutrino interactions with xenon in the nEXO detector

Electron-neutrino charged-current interactions with xenon nuclei were modeled in the nEXO neutrinoless double-𝛽 decay detector (∼5 metric ton, 90% 136 Xe, 10% 134 Xe) to evaluate its sensitivity to supernova neutrinos. Predictions for event rates and detectable signatures were modeled using the Model of Argon Reaction Low Energy Yields (MARLEY) event generator. We find good agreement between MARLEY’s predictions and existing theoretical calculations of the inclusive cross sections at supernova neutrino energies. The interactions modeled by MARLEY were simulated within the nEXO simulation framework and were run through an example reconstruction algorithm to determine the detector’s efficiency for reconstructing these events. The simulated data, incorporating the detector response, were used to study the ability of nEXO to reconstruct the incident electron-neutrino spectrum and these results were extended to a larger xenon detector of the same isotope enrichment. We estimate that nEXO will be able to observe electron-neutrino interactions with xenon from supernovae as far as 5–8 kpc from Earth, while the ability to reconstruct incident electron-neutrino spectrum parameters from observed interactions in nEXO is limited to closer supernovae.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Uncertainties in tellurium-based dark matter searches stemming from nuclear structure uncertainties

Using tellurium dioxide as a target, we calculate uncertainties on 90% upper confidence limits of Galilean effective field theory (Galilean EFT) couplings to a weakly interacting massive particle (WIMP) dark matter candidate due to uncertainties in nuclear shell models. We find that these uncertainties in naturally occurring tellurium isotopes are comparable across the different Galilean EFT couplings to uncertainties in xenon, with some reaching over 100%. We also consider the effect these nuclear uncertainties have on estimates of the annual modulation of dark matter from these searches, finding that the uncertainties in the modulation amplitude are proportional to the nonmodulating upper confidence limit uncertainties. We also show that the determination of the modulation phase is insensitive to changes in the nuclear model for a given isotope.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Overcoming photobleaching in imaging of single barium atoms in a solid xenon matrix

Neutrinoless double beta decay is one of the most sensitive probes for new physics beyond the Standard Model of particle physics. One of the isotopes under investigation is 136 Xe, which would double beta decay into 136 Ba. Detecting the single 136 Ba daughter provides a sort of ultimate tool in the discrimination against backgrounds. Previous work demonstrated the ability to perform single atom imaging of Ba atoms in a single-vacancy site of a solid xenon matrix. In this paper, the effort to identify signal from individual barium atoms is extended to Ba atoms in a hexa-vacancy site in the matrix and is achieved despite increased photobleaching in this site. Abrupt fluorescence turn-off of a single Ba atom is also observed. Significant recovery of fluorescence signal lost through photobleaching is demonstrated upon annealing of Ba deposits in the Xe ice. Following annealing, it is observed that Ba atoms in the hexa-vacancy site exhibit antibleaching while Ba atoms in the tetra-vacancy site exhibit bleaching. This may be evidence for a matrix site transfer upon laser excitation. Our findings offer a path of continued research toward tagging of Ba daughters in all significant sites in solid xenon.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Precise half-life determination of 131 Ba and 125 Xe

Barium-131 and Xenon-125 are valuable radioisotopes with numerous scientific and medical applications. Here, we produced both isotopes via proton irradiation of a cesium iodide (CsI) target at the Brookhaven Tandem Van de Graaff accelerator (BTVG). Following irradiation, we conducted systematic γ-ray spectroscopy measurements at the National Nuclear Data Center (NNDC) decay station using a calibrated High-Purity Germanium (HPGe) detector, collecting data over a 2-month period (spanning approximately 4.5 half-lives for 131 Ba). Through careful analysis of the characteristic γ-ray emissions from both isotopes, we determined the half-life of 131 Ba to be 11.55(6) days, which agrees with the previously evaluated value. For 125 Xe, we measured a half-life of 16.56(8) hours, slightly lower than the evaluated value.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Ion Manipulation from Liquid Xe to Vacuum: Ba-Tagging for a nEXO Upgrade and Future 0 νββ Experiments

Neutrinoless double beta decay (0𝜈𝛽𝛽) provides a way to probe physics beyond the Standard Model of particle physics. The upcoming nEXO experiment will search for 0𝜈𝛽𝛽 decay in 136 Xe with a projected half-life sensitivity exceeding 10 28 years at the 90% confidence level using a liquid xenon (LXe) Time Projection Chamber (TPC) filled with 5 tonnes of Xe enriched to ∼90% in the 𝛽𝛽-decaying isotope 136 Xe. In parallel, a potential future upgrade to nEXO is being investigated with the aim to further suppress radioactive backgrounds and to confirm 𝛽𝛽-decay events. This technique, known as Ba-tagging, comprises extracting and identifying the 𝛽𝛽-decay daughter 136 Ba ion. One tagging approach being pursued involves extracting a small volume of LXe in the vicinity of a potential 𝛽𝛽-decay using a capillary tube and facilitating a liquid-to-gas phase transition by heating the capillary exit. The Ba ion is then separated from the accompanying Xe gas using a radio-frequency (RF) carpet and RF funnel, conclusively identifying the ion as 136 Ba via laser-fluorescence spectroscopy and mass spectrometry. Simultaneously, an accelerator-driven Ba ion source is being developed to validate and optimize this technique. The motivation for the project, the development of the different aspects, along with the current status and results, are discussed here.

a-tagging↗
DOE OSTI2024

Photonuclear Production of Radioxenon for Air Samples

Radioxenon plays an important role in ensuring compliance with the Comprehensive Nuclear-Test-Ban Treaty due to its ability to be transported through the atmosphere, as well as the fact that the half-lives of its isotopes provide a window long enough to be detected but not long enough that it could become background radiation. This allows it to be correlated with specific events that indicate the testing of nuclear weapons. Idaho National Laboratory supports this mission by providing spiked air samples for monitoring stations to enable instrument calibration and ensure measurement accuracy. We tested a photonuclear method of producing one of the main isotopes of radioxenon, Xe-135. We also tested the separation of Xe-135 from the parent isotope Xe-136 using the method of kinematic recoil. Aluminum coils were placed in quartz ampoules filled with enriched Xe-136 and were irradiated by a bremsstrahlung beam with an endpoint energy of 21 MeV. The results showed that we were not only successful in producing Xe-135 but also that the Xe-135 was deposited into the coil allowing it to be removed from the Xe-136 gas. The coil and the Xe-135 can then be chemically separated. At the time of counting the coil, it was calculated that there was about 18 Bq of activity from Xe-135 remaining in the coil. Future work includes determining the optimal material and geometry of the catcher to maximize the amount of Xe-135 captured.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2024

133Xe Noble Gas Mass Spectrometry Measurement for High Purity Germanium Detector Performance Verification

Idaho National Laboratory produces quality control standards for laboratories that operate xenon radionuclide monitoring systems. Activities reported with each quality control standard are quantified using high purity germanium detectors. A collection of measurement capabilities are being set up at Idaho National Laboratory to establish an in-house high purity germanium detector performance verification system, with noble gas mass spectrometry being one of these measurement capabilities. The first noble gas mass spectrometry and high purity germanium measurement comparison is presented here. A Xe-133 gas sample was prepared and the activity was quantified with high purity germanium detectors. The Xe-133 sample was diluted with a known quantity of isotopically enriched Xe-126 gas; the resulting Xe-133 : Xe-126 atom ratio was calculated to be 1.15x10-4 +/- 2% at reference time t. An aliquot of this gas sample containing approximately 10 million Xe-133 atoms was introduced into a ThermoFisher Scientific Helix MC Plus noble gas mass spectrometer for analysis. The measured Xe-133 : Xe-126 atom ratio was determined to be 1.10x10-4 +/- 2% (1-sigma uncertainty) at reference time t, about 4.3% lower than the atom ratio determined with the measured high purity germanium activity.

46 - INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AN↗
DOE OSTI2025

Influence of background sources and topographic resolution in the Weather Research and Forecasting Model on xenon plume characteristics at monitoring stations

For many atmospheric monitoring applications, networks of measurement sites—such as the radionuclide stations of the International Monitoring System—can be sparse. With measurement locations potentially hundreds to thousands of kilometers from a release it is important to quantify the effects of physical processes on transport and dispersion of plumes between source and measurement locations. This study addresses the effects of background sources and topography resolution near the release location of radionuclides. We use the Weather Research and Forecasting (WRF) model with inline chemistry to investigate (1) how an additional, time-varying source of 133 Xe, such as an operational medical isotope production facility, contributes to activity concentration measurements at monitoring sites, and (2) how complex topography influences on atmospheric conditions near emission sources impact plume concentrations at varying distances from the source. Two 133 Xe emission sources, including (1) a high flux rate of short duration representing an explosive event, and (2) a variable and continuous background source, are simulated. The continuous background source contributes significantly to total 133 Xe concentrations at several monitoring stations. Further, a WRF simulation at 9 km horizontal resolution is compared with a nested grid simulation, where the innermost domain has a resolution of 1 km. Increased topographic resolution leads to an improved representation of plume responses to local winds, with topographic influences greatest at locations closest to the sources. Differences between the two domain resolutions decrease at greater distances from the sources, as plumes have time to spread and mix and are influenced by synoptic scale circulation patterns that are represented similarly in both simulations.

54 ENVIRONMENTAL SCIENCES↗