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DOE OSTI2026

AMAROK: A Radio Frequency Development Platform for High-Power, Full-Scale Positive Ion Sources for DIII-D Neutral Beam Injectors

Next-generation neutral beam injection (NBI) systems demand RF ion sources capable of efficiently coupling >120 kW at 2–4-MHz frequencies, yet existing designs face voltage standoff and impedance-matching challenges. To address this, the advanced multicoil antenna for RF operations at kilowatts (AMAROK) was developed as a high-power RF inductively coupled plasma (ICP) source delivering up to 200 kW in the 2–4-MHz range via four phase-controlled generators for flexible power sharing. Two antenna designs—a single-strap multiturn (MT) and a multistrap single-turn (ST) design—were evaluated to optimize resonance, impedance matching, and power coupling across plasma loads. Here, a semi-analytical self-resonant frequency (SRF) model, validated experimentally, predicts resonance trends for arbitrary turn counts and tubing diameters, enabling rapid antenna optimization. Strap-to-strap mutual inductance in the ST configuration showed strong spatial dependence, guiding generator operation and total load inductance. These insights informed a custom π -topology matching network, achieving stable impedance matching over a wide range of plasma-driven loads. Collectively, these results position AMAROK as a versatile testbed for advancing high-power RF source technology in fusion NBI applications.

DIII-D↗

DOE OSTI2018

Safeguards Technology Development Program 1st Quarter FY 2018 Report

LLNL will evaluate the performance of a stilbene-based scintillation detector array for IAEA neutron multiplicity counting (NMC) applications. This effort will combine newly developed modeling methodologies and recently acquired high-efficiency stilbene detector units to quantitatively compare the prototype system performance with the conventional He-3 counters and liquid scintillator alternatives.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗

DOE OSTI2018

Safeguards Technology Development Program 3rd Quarter FY 2018 Report

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

NASA NTRS1984

Evaluation of corn/soybeans separability using Thematic Mapper and Thematic Mapper Simulator data

Multitemporal Thematic Mapper, Thematic Mapper Simulator, and detailed ground truth data were collected for a 9- by 11-km sample segment in Webster County, IA, in the summer of 1982. Three dates were acquired each with Thematic Mapper Simulator (June 7, June 23, and July 31) and Thematic Mapper (August 2, September 3, and October 21). The Thematic Mapper Simulator data were converted to equivalent TM count values using TM and TMS calibration data and model based estimates of atmospheric effects. The July 31, TMS image was compared to the August 2, TM image to verify the conversion process. A quantitative measure of proportion estimation variance (Fisher information) was used to evaluate the corn/soybeans separability for each TM band as a function of time during the growing season. The additional bands in the middle infrared allowed corn and soybeans to be separated much earlier than was possible with the visible and near-infrared bands alone. Using the TM and TMS data, temporal profiles of the TM principal components were developed. The greenness and brightness exhibited behavior similar to MSS greenness and brightness for corn and soybeans.

Pitts, D. E.↗

NASA NTRS1993

An integral equation solution for multistage turbomachinery design calculations

A method was developed to calculate flows in multistage turbomachinery. The method is an extension of quasi-three-dimensional blade-to-blade solution methods. Governing equations for steady compressible inviscid flow are linearized by introducing approximations. The linearized flow equations are solved using integral equation techniques. The flows through both stationary and rotating blade rows are determined in a single calculation. Multiple bodies can be modelled for each blade row, so that arbitrary blade counts can be analyzed. The method's benefits are its speed and versatility.

Mcfarland, Eric R.↗

NASA NTRS2012

A Swift Look at SN 2011fe: The Earliest Ultraviolet Observations of a Type Ia Supernova

We present the earliest ultraviolet (UV) observations of the bright Type Ia supernova SN 2011fe/PTF11kly in the nearby galaxy M101 at a distance of only 6.4 Mpc. It was discovered shortly after explosion by the Palomar Transient Factory and first observed by Swift/UVOT about a day after explosion. The early UV light is well-defined, with approx. 20 data points per filter in the 5 days after explosion. With these early UV observations, we extend the near-UV template of SNe Ia to earlier times for comparison with observations at low and high redshift and report fits from semiempirical models of the explosion. We find the early UV count rates to be well fit by the superposition of two parabolic curves. Finally, we use the early UV flux measurements to examine a possible shock interaction with a non-degenerate companion. We find that even a solar mass companion at a distance of a few solar radii is unlikely at more than 95% confidence.

Oates, Samantha↗

NASA NTRS2024

Observed Correlation Between Local Topography and Passive Neutron Measurements from the Dynamic Albedo of Neutrons (DAN) Instrument on the Mars Science Laboratory (MSL) Rover

The Dynamic Albedo of Neutrons (DAN) instrument on the Mars Science Laboratory Curiosity rover primarily measures neutrons that have undergone interactions with rocks and materials in the rover's local environment. As the rover ascends Aeolis Mons, it may encounter more extreme local topography (e.g., cliffs, gullies, canyons). We present three parts of the rover's traverse in which local topography, expressed as the average local relief relative to the rover, is moderately to strongly correlated with an increase in passive thermal neutron count rates. These increases in count rates are consistent with results from radiation transport models of the instrument's performance near simulated topographic features. Additional DAN measurements in areas of high average local relief (>0.25 m) within 5 m of the instrument could bolster this correlation. DAN's sensitivity to topography in its passive mode could be utilized as a new measurement capability and has implications for the operation of future landed missions carrying neutron spectrometers (e.g., VIPER, MoonRanger, Lunar-VISE).

Steven D Dibb↗

DOE OSTI2014

A New Integrated Onboard Charger and Accessory Power Converter for Plug-in Electric Vehicles

In this paper, a new approach is presented for integrating the function of onboard battery charging into the traction drive system and accessory dc-dc converter of a plug-in electric vehicle (PEV). The idea is to utilize the segmented traction drive system of a PEV as the frond converter of the charging circuit and the transformer and high voltage converter of the 14 V accessory dc-dc converter to form a galvanically isolated onboard charger. Moreover, a control method is presented for suppressing the battery current ripple component of twice the grid frequency with the reduced dc bus capacitor in the segmented inverter. The resultant integrated charger has lower cost, weight, and volume than a standalone charger due to a substantially reduced component count. The proposed integrated charger topology was verified by modeling and experimental results on a 5.8 kW charger prototype.

Su, Gui-Jia↗

DOE OSTI2025

Photon-Counting Interferometry to Detect Geontropic Space-Time Fluctuations with GQuEST

The gravity from the quantum entanglement of space-time (GQuEST) experiment uses tabletop-scale Michelson laser interferometers to probe for fluctuations in space-time. We present a practicable interferometer design featuring a novel photon-counting readout method that provides unprecedented sensitivity, as it is not subject to the interferometric standard quantum limit. We evaluate the potential of this design to measure space-time fluctuations motivated by recent “geontropic” quantum gravity models. The accelerated accrual of Fisher information offered by the photon-counting readout enables GQuEST to detect the predicted quantum gravity phenomena within measurement times at least 100 times shorter than equivalent conventional interferometers. The GQuEST design, thus, enables a fast and sensitive search for signatures of quantum gravity in a laboratory-scale experiment.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2016

Stochastic analog neutron transport with TRIPOLI-4 and FREYA: Bayesian uncertainty quantification for neutron multiplicity counting

From nuclear safeguards to homeland security applications, the need for the better modeling of nuclear interactions has grown over the past decades. Current Monte Carlo radiation transport codes compute average quantities with great accuracy and performance; however, performance and averaging come at the price of limited interaction-by-interaction modeling. These codes often lack the capability of modeling interactions exactly: for a given collision, energy is not conserved, energies of emitted particles are uncorrelated, and multiplicities of prompt fission neutrons and photons are uncorrelated. Many modern applications require more exclusive quantities than averages, such as the fluctuations in certain observables (e.g., the neutron multiplicity) and correlations between neutrons and photons. In an effort to meet this need, the radiation transport Monte Carlo code TRIPOLI-4® was modified to provide a specific mode that models nuclear interactions in a full analog way, replicating as much as possible the underlying physical process. Furthermore, the computational model FREYA (Fission Reaction Event Yield Algorithm) was coupled with TRIPOLI-4 to model complete fission events. As a result, FREYA automatically includes fluctuations as well as correlations resulting from conservation of energy and momentum.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2012

Discontinuous Galerkin Dynamical Core in HOMME

Atmospheric numerical modeling has been going through radical changes over the past decade. One major reason for this trend is due to the recent paradigm change in scientific computing , triggered by the arrival of petascale computing resources with core counts in the tens of thousands to hundreds of thousands range. Modern atmospheric modelers must adapt grid systems and numerical algorithms to facilitate an unprecedented levels of scalability on these modern highly parallel computer architectures. The numerical algorithms which can address these challenges should have the local properties such as high on-processor floating-point operation count to bytes moved and minimum parallel communication overhead.

17 WIND ENERGY↗

DOE OSTI2021

Machine Learning-enabled Scalable Performance Prediction of Scientific Codes

Hardware architectures become increasingly complex as the compute capabilities grow to exascale. Here, we present the Analytical Memory Model with Pipelines (AMMP) of the Performance Prediction Toolkit (PPT). PPT-AMMP takes high-level source code and hardware architecture parameters as input and predicts runtime of that code on the target hardware platform, which is defined in the input parameters. PPT-AMMP transforms the code to an (architecture-independent) intermediate representation, then (i) analyzes the basic block structure of the code, (ii) processes architecture-independent virtual memory access patterns that it uses to build memory reuse distance distribution models for each basic block, and (iii) runs detailed basic-block level simulations to determine hardware pipeline usage. PPT-AMMP uses machine learning and regression techniques to build the prediction models based on small instances of the input code, then integrates into a higher-order discrete-event simulation model of PPT running on Simian PDES engine. We validate PPT-AMMP on four standard computational physics benchmarks and present a use case of hardware parameter sensitivity analysis to identify bottleneck hardware resources on different code inputs. We further extend PPT-AMMP to predict the performance of a scientific application code, namely, the radiation transport mini-app SNAP. To this end, we analyze multi-variate regression models that accurately predict the reuse profiles and the basic block counts. We validate predicted SNAP runtimes against actual measured times.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2018

Effects of Blending and In-Tank Pretreatment on Direct Feed Hanford High Level Waste Vitrification - 18434

A direct feed high level waste (DFHLW) option is under consideration for early operations of the Hanford Tank Waste Treatment and Immobilization Plant (WTP). In this option, the Pretreatment Facility would be bypassed in order to support an earlier start-up of the HLW Vitrification Facility. For HLW, this would mean that ultrafiltration and caustic leaching that would otherwise have been performed either would not be performed or would be replaced by interim pretreatment functions such as in-tank washings. These changes could result in higher aluminum contents, higher chromium contents, higher fractions of supernate, and lower solids contents in the HLW feed. As a result, glass formulations and downstream vitrification operations will be impacted. In the present work, we investigate the effects of various waste blending and in-tank pretreatment scenarios on DFHLW glass waste loadings, canister counts, and processing rates. Eleven source tanks and five waste groups were selected for the studies of waste blending. In addition, the five waste groups selected were the subjects of an in-tank pretreatment study. Glass property-composition models and melter test data were used to calculate waste loadings, canister counts, processing rates, and treatment durations for a range of DFHLW scenarios. The processing scenarios were defined by the types of waste blending and in-tank pretreatment that were assumed. Blending cases were evaluated that ranged between the 'No Blend' and 'Total Blend' extremes and included pairwise blending (blending of two source tanks, either completely or in various proportions) and macro-batches formed from various combinations of the source tanks. Over 36,000 possible pairwise blending scenarios were evaluated and an optimal retrieval/blending sequence was identified. The waste loading of this optimal sequence is within 0.03 wt% of the 'Total Blend' case. Further, a total of 38 retrieval sequences were identified that have waste loadings within 0.1 wt% of the 'Total Blend' case. To evaluate the effects of in-tank pretreatment, an in-tank wash/settle/decant process was assumed and tank-specific wash factors were employed. Washing of the macro-batch blends gave a general increase in HLW loading, decrease in canister count, and decrease in glass yield. Glass yields are towards the low end of the values expected for the WTP, which could lead to lower than nominal glass production rates. The waste loading increases and canister count reductions with washing were small for two of the wastes indicating that direct treatment of the unwashed waste may be practical. For wastes that are relatively low in sulfate and halides, excessive washing is counterproductive. The results highlight the importance of maintaining high solids content in the HLW feed to maintain glass production rates. The results also illustrate that the optimum washing strategy will need to be evaluated on a tank-to-tank basis. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2020

Radiation Source Localization Using Surrogate Models Constructed from 3-D Monte Carlo Transport Physics Simulations

Recent research has focused on the development of surrogate models for radiation source localization in a simulated urban domain. We employ the Monte Carlo N-Particle (MCNP) code to provide high- delity simulations of radiation transport within an urban domain. The model is constructed to employ a source location (x, y, z) as input and return the estimated count rate for a set of speci ed detector locations. Because MCNP simulations are computationally expensive, we develop e cient and accurate surrogate models of the detector responses. We construct surrogate models using Gaussian processes (GP) and neural networks (NN) that we train and verify using the MCNP simulations. The trained surrogate models provide an e cient framework for Bayesian inference and experimental design. We employ Delayed Rejection Adaptive Metropolis (DRAM), a Markov Chain Monte Carlo (MCMC) algorithm, to infer the location and intensity of an unknown source. The DRAM results yield a posterior probability distribution for the source's location conditioned on the observed detector count rates. The posterior distribution exhibits regions of high and low probability within the simulated environment identifying potential source locations. In this manner, we can quantify the source location to within at least one of these regions of high probability in the considered cases. Employing these methods, we are able to reduce the space of potential source locations by at least 60%.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2017

A Dasymetric-Based Monte Carlo Simulation Approach to the Probabilistic Analysis of Spatial Variables

Monte Carlo simulation is a popular numerical experimentation technique used in a range of scientific fields to obtain the statistics of unknown random output variables. Despite its widespread applicability, it can be difficult to infer required input probability distributions when they are related to population counts unknown at desired spatial resolutions. To overcome this challenge, we propose a framework that uses a dasymetric model to infer the probability distributions needed for a specific class of Monte Carlo simulations which depend on population counts.

Morton, April↗

DOE OSTI2013

Hemispherical power asymmetry from scale-dependent modulated reheating

We propose a new model for the hemispherical power asymmetry of the CMB based on modulated reheating. Non-Gaussianity from modulated reheating can be small enough to satisfy the bound from Planck if the dominant modulation of the inflaton decay rate is linear in the modulating field σ. σ must then acquire a spatially-modulated power spectrum with a red scale-dependence. This can be achieved if the primordial perturbation of σ is generated via tachyonic growth of a complex scalar field. Modulated reheating due to σ then produces a spatially modulated and scale-dependent sub-dominant contribution to the adiabatic density perturbation. We show that it is possible to account for the observed asymmetry while remaining consistent with bounds from quasar number counts, non-Gaussianity and the CMB temperature quadupole. The model predicts that the adiabatic perturbation spectral index and its running will be modified by the modulated reheating component.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2018

Radiation Shielding Calculations for E1039 Seaquest Experiment

The E1039 Seaquest experiment is designed to study results of interactions of the 120 GeV proton beam, delivered from Main Injector, with transversely polarized hydrogen target in the form of liquid ammonia (NH3). The E1039 experiment is re-using the Neutrino-Muon beamline, spectrometer magnet (FMAG), KMAG, and other hardware from its predecessor—the E906 experiment. Only the central 2 Tesla magnetic field was modeled in the FMAG magnet which also serves also as a beam absorber. Various updates were performed to the beamline and shielding around the magnet compared to E906 including relocation of the target 3 meters upstream of the front face of FMAG. Further, several updates were performed on the MARS15 model developed previously [1-2] in order to better describe important surrounding areas, in particular the counting room. Several optimization iterations of the shielding design were done and only the final configuration is discussed in this document. The model includes realistically stacked concrete shielding blocks along with airgaps required for piping, ductwork and detectors. The main features of the shielding update can be summarized as follows: (i) additional concrete shielding was added above the magnet to degrade the energy of neutrons to thermal levels; (ii) a new target alcove with the target cryostat inside. These updates are intended to provide increased protection for both normal operation and accident conditions upstream of the target. The Figures 1 thru 3 below describe the MARS15 model in detail as well as an excerpt of the 3D CAD model design which was used to build the MARS15 model.

43 PARTICLE ACCELERATORS↗

NASA NTRS1994

Large-angle cosmic microwave background anisotropies in an open universe

If the universe is open, scales larger than the curvature scale may be probed by observation of large-angle fluctuations in the cosmic microwave background (CMB). We consider primordial adiabatic perturbations and discuss power spectra that are power laws in volume, wavelength, and eigenvalue of the Laplace operator. Such spectra may have arisen if, for example, the universe underwent a period of `frustated' inflation. The resulting large-angle anisotropies of the CMB are computed. The amplitude generally increases as Omega is decreased but decreases as h is increased. Interestingly enough, for all three Ansaetze, anisotropies on angular scales larger than the curvature scale are suppressed relative to the anisotropies on scales smaller than the curvature scale, but cosmic variance makes discrimination between various models difficult. Models with 0.2 approximately less than Omega h approximately less than 0.3 appear compatible with CMB fluctuations detected by Cosmic Background Explorer Satellite (COBE) and the Tenerife experiment and with the amplitude and spectrum of fluctuations of galaxy counts in the APM, CfA, and 1.2 Jy IRAS surveys. COBE normalization for these models yields sigma(sub 8) approximately = 0.5 - 0.7. Models with smaller values of Omega h when normalized to COBE require bias factors in excess of 2 to be compatible with the observed galaxy counts on the 8/h Mpc scale. Requiring that the age of the universe exceed 10 Gyr implies that Omega approximately greater than 0.25, while requiring that from the last-scattering term in the Sachs-Wolfe formula, large-angle anisotropies come primarily from the decay of potential fluctuations at z approximately less than 1/Omega. Thus, if the universe is open, COBE has been detecting temperature fluctuations produced at moderate redshift rather than at z approximately 1300.

Kamionkowski, Marc↗