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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Image plate multi-scan response to fusion protons in the range of 1–14 MeV

Image plates (IPs) are a quickly recoverable and reusable radiation detector often used to measure proton and x-ray fluence in laser-driven experiments. Recently, IPs have been used in a proton radiography detector stack on the OMEGA laser, a diagnostic historically implemented with CR-39, or radiochromic film. The IPs used in this and other diagnostics detect charged particles, neutrons, and x-rays indiscriminately. IPs detect radiation using a photo-stimulated luminescence (PSL) material, often phosphor, in which electrons are excited to metastable states by ionizing radiation. Protons at MeV energies deposit energy deeper into the IP compared with x rays below ∼20 keV due to the Bragg peak present for protons. This property is exploited to discriminate between radiation types. Doses of mono-energetic protons between 1.7 and 14 MeV are applied to IPs using the MIT linear electrostatic ion accelerator. This paper presents the results from consecutive scans of IPs irradiated with different proton energies. The PSL ratios between subsequent scans are shown to depend on proton energy, with higher energy protons having lower PSL ratios for each scan. This finding is separate from the known energy dependence in the absolute sensitivity of IPs. The results can be compared to complimentary work on x rays, showing a difference between protons and x rays, forging a path to discriminate between proton and x-ray fluence in mixed radiation environments.

Instruments & Instrumentation↗
DOE OSTI2025

Investigating Radiation-Induced Actinide Species in Solution

Our fundamental understanding of actinide radiation-induced redox chemistry is crucial to nuclear fuel cycle development, due to the unavoidable exposure of these elements to ionizing radiation fields, both inherent and from in-process applications. Plutonium (Pu) and americium (Am) both possess multiple oxidation states, the careful manipulation of which are essential in the study and utilization of their rich chemistry, developing new nuclear technologies, and securing the long-term sustainability of nuclear power. However, knowledge in this area is far from complete. Consequently, we have studied the radiation-induced chemistry of both Pu and Am through a variety of techniques. Temperature-controlled electron pulse radiolysis has been used to study Am for the first time, determining the feasibility of Am redox reactions under used nuclear fuel reprocessing conditions, (e.g. nitric acid, non-ambient temperature). Additionally, we have developed an experimentally evaluated multi-scale computer model for the prediction of gamma radiation-induced Pu redox chemistry due to radiolysis and disproportionation reactions in concentrated nitric acid solutions.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2024

The Role of Radiation-Induced Non-Equilibrium Plutonium Oxidation States in Solution

Plutonium plays a key role in global actinide research and nuclear fuel cycle technologies, and yet, our fundamental understanding of its inherent radiation-induced chemical behavior is limited. These radiation-induced processes cannot simply be switched off, as they are as fundamentally inherent to plutonium as the impact of relativistic effects on its f-electrons. In less chemically complex actinide systems, such as aqueous solutions of neptunium and americium, both steady-state and transient radiolysis products play a significant role in the redox cycling of their oxidation states, which ultimately impacts their chemistry and transport. However, plutonium's multiple, coexisting, and chemically active oxidation states, which comprise of bare ions and dioxo cations, provide additional redox pathways that complicate the aforementioned radiation-induced competition kinetics. Mechanistically understanding the response of these multiple oxidation states, both equilibrium and non-equilibrium, to intense ionizing radiation fields is essential for predicting the behavior of plutonium under a host of conditions that support technological innovation in global nuclear energy and non-proliferation efforts. Here, advances in radiation-induced plutonium solution chemistry will be presented, including new results from time-resolved electron pulse and steady-state gamma and alpha irradiations.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2020

Induced Metal-free Star Formation around a Massive Black Hole Seed

The direct formation of a massive black hole is a potential seeding mechanism of the earliest observed supermassive black holes. We investigate how the existence of a massive black hole seed impacts the ionization and thermal state of its pre-galactic host halo and subsequent star formation. We show that its X-ray radiation ionizes and heats the medium, enhancing H 2 formation in shielded regions, within the nuclear region in the span of a million years. The enhanced molecular cooling triggers the formation of a ~10 4 M⊙ metal-free stellar cluster at a star formation efficiency of ~0.1% in a single event. Star formation occurs near the edges of the H ii region that is partially ionized by X-rays; thus, the initial size depends on the black hole properties and surrounding environment. Furthermore, the simulated metal-free galaxy has an initial half-light radius of ~10 pc but expands to ~50 pc after 10 million years because of the outward velocities of their birth clouds. Supernova feedback then quenches any further star formation for tens of millions of years, allowing the massive black hole to dominate the spectrum once the massive metal-free stars die.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Magneto-optical measurement of magnetic field and electrical current on a short pulse high energy pulsed power accelerator

We describe a direct magneto-optical approach to measuring the magnetic field driven by a narrow pulse width (<10 ns), 20 kA electrical current flow in the transmission line of a high energy pulsed power accelerator. The magnetic field and electrical current are among the most important operating parameters in a pulsed power accelerator and are critical to understanding the properties of the radiation output. However, accurately measuring these fields and electrical currents using conventional pulsed power diagnostics is difficult due to the strength of ionizing radiation and electromagnetic interference. Our approach uses a fiber coupled laser beam with a rare earth element sensing crystal sensor that is highly resistant to electromagnetic interference and does not require external calibration. Here, we focus on device theory, operating parameters, results from an experiment on a high energy pulsed power accelerator, and comparison to a conventional electrical current shunt sensor.

42 ENGINEERING↗
DOE OSTI2024

A Million Person Study Innovation: Evaluating Cognitive Impairment and other Morbidity Outcomes from Chronic Radiation Exposure Through Linkages with the Centers for Medicaid and Medicare Services Assessment and Claims Data

Here, the study of One Million U.S. Radiation Workers and Veterans, the Million Person Study (MPS), examines the health consequences, both cancer and non-cancer, of exposure to ionizing radiation received gradually over time. Recently the MPS has focused on mortality patterns from neurological and behavioral conditions, e.g., Parkinson's disease, Alzheimer's disease, dementia, and motor neuron disease such as amyotrophic lateral sclerosis. A fuller picture of radiation-related late effects comes from studying both mortality and the occurrence (incidence) of conditions not leading to death. Accordingly, the MPS is identifying neurocognitive diagnoses from fee-for-service insurance claims from the Centers for Medicare and Medicaid Services (CMS), among Medicare beneficiaries beginning in 1999 (the earliest date claims data are available). Linkages to date have identified ∼540,000 workers with available health information. Such linkages provide individual information on important co-factor and confounding variables such as smoking, alcohol consumption, blood pressure, obesity, diabetes and many other health and demographic characteristics. The total person-level set of time-dependent variables, outcomes, organ-specific dose measures, co-factors, and demographics will be massive and much too large to be evaluated with standard software. Thus, development of specialized open-source software designed for large datasets (Colossus) is nearly complete. The wealth of information available from CMS claims data, coupled with individual dose reconstructions, will thus greatly enhance the quality and precision of health evaluations for this new field of low-dose radiation and neurocognitive effects.

Dauer, Lawrence T.↗
DOE OSTI2021

Transamericium Radiation-Induced Redox Chemistry

The actinide series boasts many unique physical and chemical features worthy of study. However, the chemical influence of their inherent radiation field is often overlooked, especially as we begin to explore the late actinides (transamericium) in more detail than ever possible before. - Absorption of ionizing radiation induces the formation of a variety of transient and steady-state radicals, ions, and molecular degradation products. Many of these radiolysis products are strongly redox active and exhibit significant reactivity with a number of actinides, e.g., neptunium and americium. Here we present results from the first-ever time-resolved picosecond pulsed electron radiolysis measurements for the reaction of the late actinides (curium and californium) with reactive transients pertinent to actinide manipulations in aqueous solution, i.e., the hydrated electron (eaq–), the hydrogen atom (H•), and hydroxyl (•OH) and nitrate (•NO3) radicals.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2021

Autoionizing Polaritons in Attosecond Atomic Ionization

Light-induced states and Autler-Townes splitting of laser-coupled states are common features in the photoionization spectra of laser-dressed atoms. The entangled light-matter character of metastable Autler-Townes multiplets, which makes them autoionizing polaritons, however, is still largely unexplored. We employ attosecond transient-absorption spectroscopy in argon to study the formation of polariton multiplets between the 3s –1 4p and several light-induced states. We measure a controllable stabilization of the polaritons against ionization, in excellent agreement with ab initio theory. Using an extension of the Jaynes-Cummings model to autoionizing states, we show that this stabilization is due to the destructive interference between the Auger decay and the radiative ionization of the polaritonic components. Furthermore, these results give new insights into the optical control of electronic structure in the continuum and unlock the door to applications of radiative stabilization in metastable polyelectronic systems.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2026

Non-Equilibrium Actinide Radiation Chemistry and the Nuclear Fuel Cycle

Invited John and Naomi Fackler Lectureship in Chemistry and English seminar at Valparaiso University, IN, USA. Actinides are inherently unstable elements that frequently coexist with other radioisotopes, generating intense ionizing radiation fields that drive the formation of non-equilibrium oxidation states. These transient species exert a profound mechanistic influence on the radiation response of actinide-containing systems due to their unique redox chemistry. Despite their importance, they remain poorly understood, yet such insight is essential for advancing actinide science and accurately predicting radiation-driven behavior. Actinide separations—critical for nuclear energy technologies, strategic deterrence, space exploration, and nuclear medicine—depend on precise control of actinide oxidation states to recover targeted elements from complex matrices such as used nuclear fuel. However, during these processes, actinides, their coordination complexes, and the separation media are all exposed to intense, multicomponent (alpha, beta, gamma, etc.) radiation fields that can alter process efficiency, selectivity, and chemical stability. Understanding, controlling, and mitigating radiation-induced reactions is therefore key to innovating and optimizing next-generation separation technologies. This seminar will provide an overview of the nuclear fuel cycle and non-equilibrium actinide radiation chemistry in the context of recovering actinides from used nuclear fuel, with a particular emphasis on direct-dissolution–based reprocessing strategies. We will explore time-resolved electron pulse radiolysis and gamma dose accumulation studies to elucidate the molecular-level roles of radiation-driven, non-equilibrium actinide species in process performance and in the radiolytic stability of organic ligands used for actinide recovery. These insights offer new pathways for designing advanced separation methods and next-generation solvent systems, with broad implications for the future of the nuclear fuel cycle.

37 - INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL C↗
DOE OSTI2020

Radiation Controllable Synthesis of Robust Covalent Organic Framework Conjugates for Efficient Dynamic Column Extraction of 99 TcO4 -

Wang et al. report here an ultra-robust imidazolium-decorated covalent organic framework (COF) conjugate fabricated by an ionizing radiation strategy for efficient capture of 99 TcO 4 -, where tunable ReO 4 - uptake up to 952 mg g -1 can be achieved by simply adjusting the γ-ray dose. The COFs feature high porosity, ultra-robust nanofiber structure, and fast adsorption kinetics, thus emphasizing their advantages in terms of column experiments.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

The inorganic chemist's guide to actinide radiation chemistry: a review

This review aims to provide an overview of the current state of radiation chemistry with respect to the actinide elements, thorium through californium. Despite the inherent radioactivity of the actinides, only a few studies explore the effects of ionizing radiation on their redox chemistry and surrounding environment. This fundamental knowledge gap, coupled with the current renaissance in actinide-based technologies such as nuclear power, space exploration, and medicine, underscores the importance of research in this interdisciplinary area. This review will focus on the interactions between reactive species formed by radiolysis with actinides and their complexes, offering an inorganic chemist's perspective on research in radiation chemistry. In addition, a thorough discussion of our current understanding of radiation-induced changes in actinide speciation in both aqueous solution and the solid-state will be provided, focusing on changes in oxidation state distribution, complexation, and secondary coordination effects within inorganic materials. Finally, this review will discuss challenges and opportunities for inorganic chemists to explore this unique intersection of fields.

Actinides↗
DOE OSTI2025

Radiation Effects on the Performance of Advanced Sulfur Monochloride Chlorination Processes

Advanced sulfur chloride-based chlorination technologies are being developed to enable efficient recycling of aluminum and zirconium-based materials used in the nuclear industry. However, the impacts of ionizing radiation on the performance of these sulfur chloride compounds are not well established, despite this being critical knowledge for assessing their feasibility and longevity under envisioned process conditions. Here, in the present article, we report on the effects of cobalt-60 gamma irradiation (≤ 5 MGy) on the aluminum alloy 6061 (AA6061-T6) chlorination yield in sulfur monochloride (S 2 Cl 2 ). Our findings indicate that, compared to nonirradiated solvent, radiation-induced changes in the chemical composition of S 2 Cl 2 —identified using Raman spectroscopy—afford an additional, dose-dependent exothermic process prior to the chlorination reaction’s typical thermodynamic behavior. We attribute this new process to reactions involving aluminum species (metal, oxide, or [oxy]hydroxides) and sulfur dichloride (SCl 2 ), an S 2 Cl 2 radiolysis product that accumulates with absorbed gamma dose, but is absent following an AA6061-T6 chlorination study. Despite the exothermicity of this new process, the overall yield of chlorination decreased with increasing preirradiation dose. Consequently, the chemical reactivity, specificity (aluminum metal vs aluminum passivation and corrosion layer constituents), and byproducts of SCl 2 must be more thoroughly evaluated to support the continued development of advanced S 2 Cl 2 chlorination technologies.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2023

Beam Test Results of the RADiCAL—A Radiation Hard Innovative EM Calorimeter

High-performance calorimetry conducted at future hadron colliders, such as the FCC-hh, poses a significant challenge for applying current detector technologies due to unprecedented beam luminosities and radiation fields. Solutions include developing scintillators that are capable of separating events at the sub-fifty picosecond level while also maintaining performance after extreme and constant neutron and ionizing radiation exposure. The radiation-hard innovative calorimeter (RADiCAL) is an approach that incorporates radiation tolerant materials in a sampling “shashlik”-style calorimeter configuration, using quartz capillaries filled with organic liquid or polymer-based wavelength shifters embedded in layers of tungsten plates and lutetium-yttrium oxyorthosilicate (LYSO) crystals. Here, this novel design intends to address the priority research directions (PRD) for calorimetry listed in the DOE basic research needs (BRN) workshop for high energy physics (HEP) instrumentation. Here we report preliminary results from an experimental run at the Fermilab Test Beam Facility (FTBF) in June 2022. These tests demonstrate that the RADiCAL concept is capable of ¡50 ps timing resolution.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Absolute magneto-optical measurement of magnetic field on a long pulse high electrical current driven solenoid

We describe a direct absolute magneto-optical approach to measuring the magnetic field driven by long pulse width (>5 ms) and high electrical current (∼kA) in a solenoidal coil. The magnetic field and electrical current are among the most important operating parameters in lightning research and electrical power distribution and are essential to understanding the properties of the radiation output in pulsed energy accelerators as well as other research platforms. However, accurately measuring these magnetic fields and electrical currents using conventional electrical diagnostics is difficult due to the strength of ionizing radiation and electromagnetic interference. Our approach uses a fiber coupled laser beam with a rare earth element material sensing crystal that is highly resistant to electromagnetic interference, allows for absolute measurement, and does not require an external calibration. Here, we focus on device theory, operating parameters, magneto-optical results from an experiment on a high current solenoid, and comparison with a calculation of the magnetic field and reference electrical current flowing downstream of the solenoid.

Owens, Israel [Sandia National Laboratories (SNL-N↗
DOE OSTI2025

Electron-ion recombination in composite interactions in liquid xenon

The response of liquid xenon to various types of ionizing radiation has been extensively studied theoretically and experimentally. Recent progress in direct detection dark matter experiments highlights the significance of composite events, where multiple particles interact with xenon simultaneously and generate overlapping ionization signatures. In these events, recombination of electrons and ions associated with different primary particles leads to additional suppression of the ionization signal, introducing a new source of uncertainty in dark matter searches and Migdal effect studies. We developed a model to estimate the recombination enhancement for overlapping low-energy particle interactions. This method, which has minimal dependence on xenon microphysics and is primarily driven by existing experimental data, yields predictions that are consistent with available measurements of composite interactions. Furthermore, we demonstrate that the model predictions are robust against xenon microphysics assumptions.

charge↗
DOE OSTI2022

Recent Advances in Radiation-Induced Actinide Redox Chemistry

The actinide series boasts many unique physical and chemical features worthy of both fundamental and applied study. However, the chemical influence of their inherent radiation field is often overlooked, especially as we begin to explore the late actinides in more detail than ever possible before. From the perspective of used nuclear fuel reprocessing, the absorption of ionizing radiation induces the formation of a variety of transient and steady-state excited states, radicals, ions, and molecular degradation products, many of which are highly redox active and can lead to significant changes in a reprocessing solvent system’s physical and chemical properties. For example, radiolysis of the actinides can drive steady-state redox distributions and the formation of non-traditional oxidation states which can complicate their separation and recovery from fission products. This scenario is further exacerbated when complexation is taken into account. Consequently, a molecular-level understanding of radiation effects on the actinides over multiple time, distance, and material domains is essential for supporting innovation in used nuclear fuel reprocessing technologies. Attaining this knowledge necessitates a firm grasp of actinide radiation chemistry to develop predictive, mechanistic, multiscale models to support engineering efforts. Presented here are several recent studies that highlight recent advances in actinide radiation chemistry, in particular, the effect of actinide complexation on ligand reactivity towards radiation-induced transients.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2026

Revealing ultrafast proton-transfer-mediated autoionization as a source of low-energy electrons in hydrogen-bonded systems

Ionizing radiation can trigger ultrafast proton transfer, a central mechanism in many chemical and biological functions, that in turn can enable or suppress electron relaxation processes and consequently cause abrupt changes in the reaction pathway. This study combines theory and experiment to probe ultrafast relaxation and dissociation in water dimers following inner- and outer-valence photoionization. By tracking electron and nuclear motion simultaneously, we reveal competing fragmentation pathways that produce low-energy electrons, which are key agents in radiation-induced chemistry, including DNA damage. While low-energy electrons are known to arise via intermolecular Coulombic decay, here we identify a faster relaxation mechanism gated by proton transfer following inner-valence ionization, which we call proton-transfer-mediated autoionization. Occurring within 10 femtoseconds, this process alters fragmentation outcomes, yielding either D 3 O + + OD + or D 2 O + + D 2 O + , depending on the interplay of proton migration and hydrogen back-transfer. Our findings underscore the intricate coupling between electronic and nuclear dynamics in hydrogen-bonded systems and establish proton-transfer-mediated autoionization as a significant pathway for low-energy electron generation.

Atomic and molecular interactions with photons↗
DOE OSTI2021

Assessing the sources of reionization: a spectroscopic case study of a 30× lensed galaxy at z ~ 5 with Ly α , C IV, Mg ιι, and [Ne ιιι]

We present a detailed spectroscopic analysis of a galaxy at z ≃ 4.88 that is, by chance, magnified ~30× by gravitational lensing. Only three sources at z ≳ 5 are known with such high magnification. This particular source has been shown to exhibit widespread, high equivalent width ${{\rm C\, \small {IV}}}\ \lambda 1549\, \mathring{\rm A}$ emission, implying it is a unique example of a metal-poor galaxy with a hard radiation field, likely representing the galaxy population responsible for cosmic reionization. Using ultraviolet (UV) nebular line ratio diagnostics, Very Large Telescope (VLT)/X-shooter observations rule out strong active galactic nuclei (AGN) activity, indicating a stellar origin of the hard radiation field instead. We present a new detection of ${[{\rm Ne\, \small {III}}]}\ \lambda 3870\, \mathring{\rm A}$ and use the [${\rm Ne\, \small {III}}$]/[${\rm O\, \small {II}}$] line ratio to constrain the ionization parameter and gas-phase metallicity. Closely related to the commonly used [${\rm O\, \small {III}}$]/[${\rm O\, \small {II}}$] ratio, our [${\rm Ne\, \small {III}}$]/[${\rm O\, \small {II}}$] measurement shows this source is similar to local ‘Green Pea’ galaxies and Lyman-continuum leakers. It furthermore suggests this galaxy is more metal poor than expected from the fundamental metallicity relation, possibly as a consequence of excess gas accretion diluting the metallicity. Finally, we present the highest redshift detection of ${{\rm Mg\, \small {II}}}\ \lambda 2796\, \mathring{\rm A}$, observed at high equivalent width in emission, in contrast to more evolved systems predominantly exhibiting ${\rm Mg\, \small {II}}$ absorption. Strong ${\rm Mg\, \small {II}}$ emission has been observed in most z ~ 0 Lyman-continuum leakers known and has recently been proposed as an indirect tracer of escaping ionizing radiation. In conclusion, this strongly lensed galaxy, observed just $300\, \mathrm{Myr}$ after reionization ends, enables testing of observational diagnostics proposed to constrain the physical properties of distant galaxies in the James Webb Space Telescope (JWST)/Extremely Large Telescope (ELT) era.

79 ASTRONOMY AND ASTROPHYSICS↗