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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

R&D toward design for a pion-production target for Mu2e-II

The Mu2e experiment at Fermilab will search for evidence of charged lepton flavor violation by observing the conversion of a negative muon into an electron in the Coulomb field of a nucleus without emission of neutrinos and will probe effective new-physics mass scales in the 103-104 TeV range. One of the main parts of the Mu2e experimental setup is its target station in which negative pions are generated in interactions of the 8 GeV primary proton beam with a tungsten target, which will be capable of producing $2\times10^{17}$ negative muons per year. Mu2e can be extended by a next generation experiment, Mu2e-II, with a sensitivity improved by another factor of 10 or more as enabled by the PIP-II accelerator upgrade project. PIP-II is a 250-meter-long linac capable of accelerating a 2 mA proton beam to a kinetic energy of 800 MeV corresponding to 1.6 MW of power. To achieve another factor of ten improvement in sensitivity, Mu2e-II will require about 100 kW of proton beam on target, and the added power requires a new target design. We will present our progress in RD of a target station conceptual design for Mu2e-II, using the MARS15 and G4beamline Monte-Carlo codes toward a selection between granular, conveyor, and rotating cylindrical target options.

Lynch, Kevin Richard↗
DOE OSTI2022

DEVELOPMENT OF A QUANTUM ELECTRON BEAM DIAGNOSTIC APPARATUS

Spatial properties of electron beams are the essential parameters needed in particle physics and accelerator research. Beam characterization using optical detection methods through the interaction between photons and electrons such as Compton scattering, or electro-optic sampling of the electric field of electrons have been extensively explored and successfully implemented as non-invasive diagnostics at various accelerator facilities. However, such methods often suffer from inherently low sensitivity. Here we present the study of a new type of electron beam diagnostic device for direct optical imaging of electron beams at various energy levels. The concept is based on the extremely high sensitivity of atoms, prepared in a specific "dark superposition" quantum state, to the external electric or magnetic perturbations induced by the passing charged particle, which allows atoms to change polarization of the probe light or absorb probe light and to fluoresce, enabling direct 3D imaging of the charged particles with high resolution. We report our recent experiment results and the design effort on a compact apparatus intended to be tested with the relativistic electron beams at Jefferson Laboratory.

Zhang, S.↗
DOE OSTI2024

Updates to the NuMI Flux Simulation at MicroBooNE (V.1.0)

The NuMI flux prediction being used by all experiments at Fermilab that are sensitive to the NuMI beam is based on Geant v4.9.2.03 (G4.9) and uses the default FTFP-BERT physics list with no custom cross sections. In order to correct these predictions to match world data, PPFX, the Package to Predict the FluX, is used to reweight the flux prediction. In kinematic regions of overlap between the prediction and data, mainly NA49 measurements are used to correct for various hadron production processes. Specifcally, PPFX looks at the entire ancestry chain of the neutrino, up to the incident 120 GeV proton beam, and applies corrections for various hadron interactions based on said data. These corrections are implemented as a function of the Feynman-x (x F ) and transverse momentum (p T ) of the incident hadron.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

SBND Analysis using ML Reconstruction Chain

As part of the Short Baseline Neutrino (SBN) Program at Fermilab, the Short Baseline Near Detector (SBND) is positioned in the Booster Neutrino Beam (BNB) and explores neutrino-argon interactions with unprecedented statistics. SBND is a Liquid Argon Time Projection Chamber (LArTPC). Electrons produced through ionization drift toward three wire planes, providing signals that form 2D images of particle trajectories. I introduce the Scalable Particle Imaging using Neural Embeddings (SPINE) framework, which employs a Machine Learning (ML)-based 3D reconstruction using a series of neural networks. Here, we present SPINE’s reconstruction chain, analysis approaches, and results from our latest simulation samples.

43 PARTICLE ACCELERATORS↗
NASA NTRS1972

Research into advanced concepts of microwave power amplification and generation utilizing linear beam devices

A theoretical study of some aspects of the interaction between a drifting stream of electrons with transverse cyclotron motions and an electromagnetic field is presented. Particular emphasis was given to the possible generation and amplification of millimeter waves. The major effort was devoted to a theoretical study of the cyclotron resonance oscillator. The appendices include published papers on the cyclotron resonance oscillator which resulted from this investigation.

Mcisaac, P. R.↗
NASA NTRS1981

Investigations of electron helicity in optically active molecules using polarized beams of electrons and positrons

A positronium-formation experiment with a high sensitivity to a possible relation between the helicity of beta particles emitted in nuclear beta decay and the optical asymmetry of biological molecules is presented. The experiment is based on a mechanism in which the electrons in optically active molecules possess a helicity of less than 0.001, too weak to detect in radiolysis experiments, the sign of which depends on the chirality of the isomer. A helicity-dependent asymmetry is sought in the formation of the triplet ground state of positronium when a low-energy beam of polarized positrons of reversible helicity interacts with an optically active substance coating a channel electron multiplier. Asymmetries between positronium decays observed at positive and negative helicities for the same substance can thus be determined with a sensitivity of 0.0001, which represents a factor of 100 improvement over previous positronium experiments.

Gidley, D. W.↗
NASA NTRS1985

Structural characterization and gas reactions of small metal particles by high-resolution TEM and TED

The interaction of 100 and 200 keV electron beams with amorphous alumina, titania, and aluminum nitride substrates and nanometer-size palladium particulate deposits was investigated for the two extreme cases of (1) large-area electron-beam flash-heating and (2) small-area high-intensity electron-beam irradiation. The former simulates a short-term heating effect with minimum electron irradiation exposure, the latter simulates high-dosage irradiation with minimum heating effect. All alumina and titania samples responded to the flash-heating treatment with significant recrystallization. However, the size, crystal structure, shape, and orientation of the grains depended on the type and thickness of the films and the thickness of the Pd deposit. High-dosage electron irradiation also readily crystallized the alumina substrate films but did not affect the titania films. The alumina recrystallization products were usually either all in the alpha phase, or they were a mixture of small grains in a number of low-temperature phases including gamma, delta, kappa, beta, theta-alumina. Palladium deposits reacted heavily with the alumina substrates during either treatment, but they were very little effected when supported on titania. Both treatments had the same, less prominent localized crystallization effect on aluminum nitride films.

Heinemann, K.↗
NASA NTRS1986

Space plasma research

Temperature and density analysis in the Automated Analysis Program (for the global empirical model) were modified to use flow velocities produced by the flow velocity analysis. Revisions were started to construct an interactive version of the technique for temperature and density analysis used in the automated analysis program. A sutdy of ion and electron heating at high altitudes in the outer plasmasphere was initiated. Also the analysis of the electron gun experiments on SCATHA were extended to include eclipse operations in order to test a hypothesis that there are interactions between the 50 to 100 eV beam and spacecraft generated photoelectrons. The MASSCOMP software to be used in taking and displaying data in the two-ion plasma experiment was tested and is now working satisfactorily. Papers published during the report period are listed.

Comfort, R. H.↗
NASA NTRS1986

Space Technology Plasma Issues in 2001

The purpose of the workshop was to identify and discuss plasma issues that need to be resolved during the next 10 to 20 years (circa 2001) to facilitate the development of the advanced space technology that will be required 20 or 30 years into the future. The workshop consisted of 2 days of invited papers and 2 sessions of contributed poster papers. During the third day the meeting broke into 5 working groups, each of which held discussions and then reported back to the conference as a whole. The five panels were: Measurements Technology and Active Experiments Working Group; Advanced High-Voltage, High-Power and Energy-Storage Space Systems Working Group; Large Structures and Tethers Working Group; Plasma Interactions and Surface/Materials Effects Working Group; and Beam Plasmas, Electronic Propulsion and Active Experiments Using Beams Working Group.

Garrett, Henry↗
NASA NTRS1987

Hypervelocity atomic oxygen source for the study of atom-surface interactions

Planned improvements in an electric discharge heated atomic oxygen beam source are described which will provide 6 to 7 kms(-1) beams of atomic oxygen with a flux of 10(16) cm(-2) s(-1) at 50 cm distance from the source aperture. A major advance will be the use of a zone of silence nozzle-skimmer arrangement which is necessitated by the need for high source flux and performance. It is anticipated that a Phase 2 program would provide for the fabrication of a two stage vacuum system which would be suitable for bolting on to a UHV (ultrahigh vacuum) surface study apparatus.

Freedman, A.↗
NASA NTRS1990

Electron beams and Langmuir turbulence in solar type III radio bursts observed in the interplanetary medium

Results are presented of in situ observations of electron beams, plasma waves, and associated solar type II radio emission in the interplanetary medium near 1 AU, which were provided by the ISEE-3 spacecraft. It is shown that electron beams are formed by the faster electrons arriving before the slower ones, following an impulsive injection at the sun. The resulting bump-on-tail in the reduced 1D distribution function is unstable to the growth of electrostatic electron plasma (Langmuir) waves. The Langmuir waves are observed to be highly impulsive in nature. The onset and temporal variations of the observed plasma waves are in good qualitative agreement with the wave growth expected from the evolution of the measured 1D distribution function. The lack of obvious plateauing of the bump-on-tail suggests that the waves were removed from resonance with the beam electrons by some wave-wave interaction.

Lin, R. P.↗
NASA NTRS1992

Plasma-beam instabilities in cometary ionospheres

It is shown that the interaction between the solar wind flux and the cometary ionosphere leads to the excitation of ion sound, whistler, electron-cyclotron, low hybrid, and magnetohydrodynamic waves. We investigated the frequency spectrum and found linear-increasing increments and lengths of excited waves.

Churyumov, Klim I.↗
NASA NTRS1993

Mechanistic investigations of shuttle glow

A series of laboratory measurements have been performed in order to provide a mechanistic interpretation for the visible shuttle glow. These studies involved interactions of an 8 km/s oxygen atom beam with both contaminant dosed surfaces and gaseous targets. We conclude that visible shuttle glow arises from surface mediated O + NO recombination via a Langmuir-Hinshelwood mechanism and that the gas-phase exchange reaction O + N2 - NO + N provides a viable source of precursor NO above surfaces oriented in the ram direction.

Caledonia, G. E.↗
NASA NTRS1995

Expendable launch vehicle studies

Analytical support studies of expendable launch vehicles concentrate on the stability of the dynamics during launch especially during or near the region of maximum dynamic pressure. The in-plane dynamic equations of a generic launch vehicle with multiple flexible bending and fuel sloshing modes are developed and linearized. The information from LeRC about the grids, masses, and modes is incorporated into the model. The eigenvalues of the plant are analyzed for several modeling factors: utilizing diagonal mass matrix, uniform beam assumption, inclusion of aerodynamics, and the interaction between the aerodynamics and the flexible bending motion. Preliminary PID, LQR, and LQG control designs with sensor and actuator dynamics for this system and simulations are also conducted. The initial analysis for comparison of PD (proportional-derivative) and full state feedback LQR Linear quadratic regulator) shows that the split weighted LQR controller has better performance than that of the PD. In order to meet both the performance and robustness requirements, the H(sub infinity) robust controller for the expendable launch vehicle is developed. The simulation indicates that both the performance and robustness of the H(sub infinity) controller are better than that for the PID and LQG controllers. The modelling and analysis support studies team has continued development of methodology, using eigensensitivity analysis, to solve three classes of discrete eigenvalue equations. In the first class, the matrix elements are non-linear functions of the eigenvector. All non-linear periodic motion can be cast in this form. Here the eigenvector is comprised of the coefficients of complete basis functions spanning the response space and the eigenvalue is the frequency. The second class of eigenvalue problems studied is the quadratic eigenvalue problem. Solutions for linear viscously damped structures or viscoelastic structures can be reduced to this form. Particular attention is paid to Maxwell and Kelvin models. The third class of problems consists of linear eigenvalue problems in which the elements of the mass and stiffness matrices are stochastic. dynamic structural response for which the parameters are given by probabilistic distribution functions, rather than deterministic values, can be cast in this form. Solutions for several problems in each class will be presented.

Bainum, Peter M.↗
NASA NTRS2001

Observations of Sea Surface Mean Square Slope During the Southern Ocean Waves Experiment

For the Southern Ocean Waves Experiment (SOWEX), conducted in June 1992 out of Hobart, Tasmania, the NASA Scanning Radar Altimeter (SRA) was shipped to Australia and installed on a CSIRO Fokker F-27 research aircraft instrumented to make comprehensive surface layer measurements of air-sea interaction fluxes. The SRA sweeps a radar beam of P (two-way) half-power width across the aircraft ground track over a swath equal to 0.8 of the aircraft height, simultaneously measuring the backscattered power at its 36 GHz (8.3 mm) operating frequency and the range to the sea surface at 64 cross-track positions. In realtime, the slant ranges are multiplied by the cosine of the off-nadir incidence angles (including the effect of aircraft roll attitude) to determine the vertical distances from the aircraft to the sea surface. These distances are subtracted from the aircraft height to produce a sea-surface elevation map, which is displayed on a monitor in the aircraft to enable real-time assessments of data quality and wave properties. The sea surface mean square slope (mss), which is predominantly caused by the short waves, was determined from the backscattered power falloff with incidence angle measured by the SRA in the plane normal to the aircraft heading. On each flight, data were acquired at 240 m altitude while the aircraft was in a 7 degree roll attitude, interrogating off-nadir incidence angles from -15 degrees through nadir to +29 degrees. The aircraft turned azimuthally through 810 degrees in this attitude, mapping the azimuthal dependence of the backscattered power falloff with incidence angle. Two sets of turning data were acquired on each day, before and after the aircraft measured wind stress at low altitude (12 meters to 65 meters). Wave topography and backscattered power for mss were also acquired during those level flight segments whenever the aircraft altitude was above the SRA minimum range of 35 m. Data were collected over a wide range of wind and sea conditions, from quiescent to gale force winds with 9 meter wave height.

Walsh, E. J.↗
NASA NTRS2004

Role of shielding in modulating the effects of solar particle events: Monte Carlo calculation of absorbed dose and DNA complex lesions in different organs

Distributions of absorbed dose and DNA clustered damage yields in various organs and tissues following the October 1989 solar particle event (SPE) were calculated by coupling the FLUKA Monte Carlo transport code with two anthropomorphic phantoms (a mathematical model and a voxel model), with the main aim of quantifying the role of the shielding features in modulating organ doses. The phantoms, which were assumed to be in deep space, were inserted into a shielding box of variable thickness and material and were irradiated with the proton spectra of the October 1989 event. Average numbers of DNA lesions per cell in different organs were calculated by adopting a technique already tested in previous works, consisting of integrating into "condensed-history" Monte Carlo transport codes--such as FLUKA--yields of radiobiological damage, either calculated with "event-by-event" track structure simulations, or taken from experimental works available in the literature. More specifically, the yields of "Complex Lesions" (or "CL", defined and calculated as a clustered DNA damage in a previous work) per unit dose and DNA mass (CL Gy-1 Da-1) due to the various beam components, including those derived from nuclear interactions with the shielding and the human body, were integrated in FLUKA. This provided spatial distributions of CL/cell yields in different organs, as well as distributions of absorbed doses. The contributions of primary protons and secondary hadrons were calculated separately, and the simulations were repeated for values of Al shielding thickness ranging between 1 and 20 g/cm2. Slight differences were found between the two phantom types. Skin and eye lenses were found to receive larger doses with respect to internal organs; however, shielding was more effective for skin and lenses. Secondary particles arising from nuclear interactions were found to have a minor role, although their relative contribution was found to be larger for the Complex Lesions than for the absorbed dose, due to their higher LET and thus higher biological effectiveness. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

Non-NASA Center↗
NASA NTRS2005

Measurement of absolute cross sections for excitation of the 2s(2) S-1 -> 2s2p P-1 degrees transition in O+4

Experimental cross sections are reported for the 1s(2)2s(2) S-1 -> 1s(2)2s2p P-1(o) transition in O+4 located at 19.689 eV. Use is made of the electron energy-loss method, using a merged electron-ion beam geometry. The center-of-mass interaction energies for the measurements in the S-1 -> P-1(o) transition are in the range 18 eV ( below the threshold) to 30 eV. Data are compared with other previous electron energy-loss measurements and with results of a 26 term R-matrix calculation that includes fine structure explicitly via the Breit-Pauli Hamiltonian. Clear resonance enhancement is observed in all experimental and theoretical results near the threshold for this S-1 -> P-1(o) transition.

atomic processes↗
NASA NTRS2016

Application of Interval Predictor Models to Space Radiation Shielding

This paper develops techniques for predicting the uncertainty range of an output variable given input-output data. These models are called Interval Predictor Models (IPM) because they yield an interval valued function of the input. This paper develops IPMs having a radial basis structure. This structure enables the formal description of (i) the uncertainty in the models parameters, (ii) the predicted output interval, and (iii) the probability that a future observation would fall in such an interval. In contrast to other metamodeling techniques, this probabilistic certi cate of correctness does not require making any assumptions on the structure of the mechanism from which data are drawn. Optimization-based strategies for calculating IPMs having minimal spread while containing all the data are developed. Constraints for bounding the minimum interval spread over the continuum of inputs, regulating the IPMs variation/oscillation, and centering its spread about a target point, are used to prevent data over tting. Furthermore, we develop an approach for using expert opinion during extrapolation. This metamodeling technique is illustrated using a radiation shielding application for space exploration. In this application, we use IPMs to describe the error incurred in predicting the ux of particles resulting from the interaction between a high-energy incident beam and a target.

Crespo, Luis G.↗