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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Uniform Beam Simulation Technique for Beam Scans and Machine Learning Studies at Fermilab

Fermilab's neutrino facilities, including NuMI and the upcoming LBNF, use proton beams to produce positively and negatively charged pions and kaons. Detailed simulations are necessary to study particle interactions and beam propagation. To efficiently analyze beam scan effects, we propose a technique to generate multiple simulation samples with high statistics. These samples can be used to develop beamline simulation based machine learning applications. In this technique, we generate a uniformly distributed single simulation data sample. We calculate Gaussian weights for each beam configurations and apply them to post-processing measurements. In this poster, we demonstrate the proposed simulation technique. This technique reduces simulation time and computing resources significantly.

Wickremasinghe, Athula↗
DOE OSTI2026

Incident beam simulations for the CNCS instrument

This data set contains incident beam simulations for the 100 most frequently used configurations of the cold neutron chopper spectrometer (CNCS) instrument at the Spallation Neutron Source. A mcpl output was placed 0.2 m upstream of the sample position. Each file provides enough events to sufficiently sample the beam profile and intensity incident on the sample for that configuration. They can then be used for sample simulations.

47 OTHER INSTRUMENTATION↗
NASA NTRS2013

Simulated Beam Extraction Performance Characterization of a 50-cm Ion Thruster Discharge

A 50 cm ion thruster is being developed to operate at >65 percent total efficiency at 11 kW, 2700 s Isp and over 25 kW, 4500 s Isp at a total efficiency of >75 percent. The engine is being developed to address the need for a multimode system that can provide a range of thrust-to- power to service national and commercial near-earth onboard propulsion needs such as station-keeping and orbit transfer. Operating characteristics of the 50 cm ion thruster were measured under simulated beam extraction. The discharge current distribution at the various magnet rings was measured over a range of operating conditions. The relationship between the anode current distribution and the resulting plasma uniformity and ion flux measured at the thruster exit plane is discussed. The thermal envelope will also be investigated through the monitoring of magnet temperatures over the range of discharge powers investigated. Discharge losses as a function of propellant utilization was also characterized at multiple simulated beam currents. Bulk plasma conditions such as electron temperature and electron density near engine centerline was measured over a range of operating conditions using an internal Langmuir probe. Sensitivity of discharge performance to chamber length is also discussed. This data acquired from this discharge study will be used in the refinement of a throttle table in anticipation for eventual beam extraction testing.

Foster, John E.↗
NASA NTRS1972

Molecular beam simulation of planetary atmospheric entry - Some recent results.

Progress is reported in the development of molecular beam techniques to simulate entry into planetary atmospheres. Molecular beam sources for producing fast beams containing CO2 and atomic oxygen are discussed. Results pertinent to the design and calibration of a mass spectrometer ion source for measurement of the Martian atmosphere during the free molecule portion of the entry trajectory are also presented. The shortcomings and advantages of this simulation technique are discussed, and it is demonstrated that even with certain inadequacies much information useful to the ion source design was obtained. Particularly, it is shown that an open-cavity configuration retains sensitivity to atomic oxygen, provides reasonable signal enhancement from the stagnation effect, is not highly sensitive to pitch and yaw effects, and presents no unforeseen problems in measuring CO2 or atomic oxygen.

French, J. B.↗
DOE OSTI2025

Study of Particle Loss in Synchrotron Phase Space Injection for ESR Using Weak-Strong Beam-Beam Simulation with Nonlinear Lattice

In this report, we use tracking simulations to investigate synchrotron phase space injection for electron accumulation in the electron storage ring of the Electron Ion Collider. Our simulation model accounts for both beam-beam interactions and lattice nonlinearities. Specifically, we examine how particle loss is influenced by various parameters. Additionally, we conduct a theoretical analysis and derive an analytical formula for the rapid evaluation of particle loss. Our results demon strate the feasibility of synchrotron phase-space injection for the electron storage ring and provide insights to guide parameter selection for the design of the injection line.

43 PARTICLE ACCELERATORS↗
NASA NTRS1972

Molecular beam simulation of planetary atmospheric entry: Some recent results

Molecular beam sources for producing fast beams containing CO2 and atomic oxygen are discussed. Results pertinent to the design and calibration of mass spectrometer ion source for measurement of the Martian atmosphere during the free molecule portion of the entry trajectory are also presented. The shortcomings and advantages of the simulation technique are discussed. It is shown that an open cavity configuration retains sensitivity to atomic oxygen, provides reasonable signal enhancement from the stagnation effect, is not highly sensitive to pitch and yaw effects, and presents no unforeseen problems in measuring CO2 or atomic oxygen. The simulation techniques used provide assistance in designing, developing, and (potentially) in testing and calibrating the required flight instrument.

French, J. B.↗
DOE OSTI2022

Beam Dynamics Simulations of Transient Beam Loading Effects in the 10GeV EIC Electron Storage Ring

We report on beam dynamics studies of transient beam loading effects in the 10 GeV EIC electron storage ring [1]. The studies are carried out with time-dependent Vlasov-Fokker-Planck simulations performed with the parallel, particle tracking code SPACE [2], which allows to follow self-consistently the dynamics of h bunches, where h in the number of RF buckets, in arbitrary multi-bunch configurations. The specific goal of the numerical simulations is to determine stable RF cavity settings under heavy beam loading. We also study the option to operate with a passive, third-harmonic cavity (3HC) system for bunch lengthening, addressing both stability and the performance limitation due to a gap in the uniform filling pattern for ion clearing.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Four-dimensional phase-space reconstruction of flat and magnetized beams using neural networks and differentiable simulations

Beams with cross-plane coupling or extreme asymmetries between the two transverse phase spaces are often encountered in particle accelerators. Flat beams with large transverse-emittance ratios are critical for future linear colliders. Similarly, magnetized beams with significant cross-plane coupling are expected to enhance the performance of electron cooling in hadron beams. Preparing these beams requires precise control and characterization of the four-dimensional transverse phase space. In this study, we employ generative phase-space reconstruction techniques to rapidly characterize magnetized and flat-beam phase-space distributions using a conventional quadrupole-scan method. The reconstruction technique is experimentally demonstrated on an electron beam produced at the Argonne Wakefield Accelerator and successfully benchmarked against conventional diagnostics techniques. Specifically, we show that predicted beam parameters from the reconstructed phase-space distributions (e.g., as magnetization and flat-beam emittances) are in excellent agreement with those measured from the conventional diagnostic methods. Published by the American Physical Society 2024

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Data driven methods to recognize patterns in EIC weak-strong simulation

Beam-Beam simulations are currently being studied in preparation for future EIC experiments to study beam-beam effects and, in turn, maximize luminosity. Weak-strong methods are studied for single-particle dynamics during collision. 1 million macro-particles for 1 million turns are typically tracked, corresponding to only 10 seconds in the EIC. The goal of this study is to predict beam properties over the scale of hours. A potential solution focuses on using data-driven methods such as machine learning methods to analyze and extend the insights of the beam properties such as long-term nonlinear effects. This would aid in long-term predictions where results would be more efficiently acquired than a typical tracking simulation. Some limitations such as inaccurate predictions and spatial complexity are also discussed. These methods can then be applied to strong-strong simulations in the future studies.

Accelerator Physics↗
DOE OSTI2023

Correct Initial Conditions for Simulations of Beam Physics in Linear Induction Accelerators

Flash radiography of hydrodynamic experiments driven by high explosives is a well-known diagnostic technique in use at many laboratories. At Los Alamos, the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility two linear induction electron accelerators (LIAs) make the bremsstrahlung radiographic source spots for point projection radiographs from orthogonal views. A new LIA, called Scorpius, is presently under development to advance this technology. To better understand electron-beam physics in these LIAs, numerical simulations are frequently performed with the objective of improving the radiography. At Los Alamos we frequently use the TRAK ray-trace and LSP particle-in-cell (PIC) codes to simulate the injector, and the XTR and LAMDA envelope/centroid codes along with LSP to simulate transport of the accelerated beam through the LIAs. The LIA simulations need the injected beam parameters as initial conditions for calculating beam transport and stability. The determination of these initial conditions is the topic of this note.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Direct Fabrication of Atomically Defined Pores in MXenes Using Feedback-Driven STEM

Controlled fabrication of nanopores in 2D materials offer the means to create robust membranes needed for ion transport and nanofiltration. Techniques for creating nanopores have relied upon either plasma etching or direct irradiation; however, aberration-corrected scanning transmission electron microscopy (STEM) offers the advantage of combining a sub-Å sized electron beam for atomic manipulation along with atomic resolution imaging. Here, for this work, a method for automated nanopore fabrication is utilized with real-time atomic visualization to enhance the mechanistic understanding of beam-induced transformations. Additionally, an electron beam simulation technique, Electron-Beam Simulator (E-BeamSim) is developed to observe the atomic movements and interactions resulting from electron beam irradiation. Using the MXene Ti 3 C 2 T x , the influence of temperature on nanopore fabrication is explored by tracking atomic transformations and find that at room temperature the electron beam irradiation induces random displacement and results in titanium pileups at the nanopore edge, which is confirmed by E-BeamSim. At elevated temperatures, after removal of the surface functional groups and with the increased mobility of atoms results in atomic transformations that lead to the selective removal of atoms layer by layer. This work can lead to the development of defect engineering techniques within functionalized MXene layers and other 2D materials.

36 MATERIALS SCIENCE↗