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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Revealing the three-dimensional structure of microbunched plasma-wakefield-accelerated electron beams

Abstract Plasma wakefield accelerators use tabletop equipment to produce relativistic femtosecond electron bunches. Optical and X-ray diagnostics have established that their charge concentrates within a micrometre-sized volume, but its sub-micrometre internal distribution, which critically influences gain in free-electron lasers or particle yield in colliders, has proven elusive to characterize. Here, by simultaneously imaging different wavelengths of coherent optical transition radiation that a laser-wakefield-accelerated electron bunch generates when exiting a metal foil, we reveal the structure of the coherently radiating component of bunch charge. The key features of the images are shown to uniquely correlate with how plasma electrons injected into the wake: by a plasma-density discontinuity, by ionizing high- Z gas-target dopants or by uncontrolled laser–plasma dynamics. With additional input from the electron spectra, spatially averaged coherent optical transition radiation spectra and particle-in-cell simulations, we reconstruct coherent three-dimensional charge structures. The results demonstrate an essential metrology for next-generation compact X-ray free-electron lasers driven by plasma-based accelerators.

43 PARTICLE ACCELERATORS↗
NASA NTRSDate not supplied

Solar Absorptivity Degradation of Spacecraft Materials Due to UV and Charged Particles in the Gateway Environment

Gateway will be an outpost in cislunar space designed to survive a 15-year mission to support human Moon landings and future deep space exploration. The Gateway Passive Thermal Control System (PTCS) Group has identified charged particle and UV degradation of potential Gateway materials as a knowledge gap for the Near Rectilinear Halo Orbit (NRHO) and transit environment, especially the slow spiral transit planned for the first two modules. Solar absorptivity degradation is important to quantify because the end-of-life absorptivity impacts thermal performance of the system. To address this, ground testing has been completed at NASA Goddard Space Flight Center in which potential Gateway materials, including radiators, multi-layer insulation (MLI), and structural materials are subjected to the expected transit plus 15-year on-orbit charged particle fluence (9.86x1015 protons/cm2 at 2.5 keV and 3.1x1016 electrons/cm2 at 10 keV) and 5093 Equivalent Solar Hours (ESH). Reflectivity of a single sample of each material was measured in atmosphere and in vacuum inside the chamber after exposure to incremental levels of ESH and charged particle fluence. Increase in absorptivity of most samples were seen throughout the test including large differences in absorptivity of materials of the same category. Future planned testing will validate these results and include additional materials of interest.

Optical Property↗
DOE OSTI2025

The SHMS 11 GeV/c spectrometer in Hall C at Jefferson Lab

The Super High Momentum Spectrometer (SHMS) has been built for Hall C at the Thomas Jefferson National Accelerator Facility (Jefferson Lab). With a momentum capability reaching 11 GeV/ c , the SHMS provides measurements of charged particles produced in electron-scattering experiments using the maximum available beam energy from the upgraded Jefferson Lab accelerator. The SHMS is an ion-optics magnetic spectrometer comprised of a series of new superconducting magnets which transport charged particles through an array of triggering, tracking, and particle-identification detectors that measure momentum, energy, angle and position in order to allow kinematic reconstruction of the events back to their origin at the scattering target. The detector system is protected from background radiation by a sophisticated shielding enclosure. The entire spectrometer is mounted on a rotating support structure which permits measurements to be taken with a large acceptance over laboratory scattering angles from 5.5° to 40°, thus allowing a wide range of low cross-section experiments to be conducted. Finally, these experiments complement and extend the previous Hall C research program to higher energies.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS2017

Deep-Space Navigation Using Optical Communications Systems

Optical communication links using lasers can potentially deliver data rates much higher than those possible using radio frequencies. If optical communications equipment is going to be carried by future deep-space missions, this equipment, with some adaptations, could also be used to perform tracking for trajectory determination. A number of experiments have been performed in Earth orbit and in lunar orbit using optical data links, while other missions have demonstrated optical links over interplanetary distances. Laser ranging using corner cube retroreflectors is a well-established technique that has been used for orbit determination of Earth orbiting spacecraft, for geodesy, and for lunar research, achieving centimeter-level precisions, but it is not a practical method for deep-space distances. There are two main optical tracking types that are being considered for deep-space navigation. The first is optical astrometry of spacecraft: a telescope on the ground images the laser beam coming from a spacecraft against the star background, determining its plane-of-sky position as seen from the observatory. This type will greatly benefit from the release of the high-accuracy star catalog produced by ESA’s Gaia mission, allowing for the generation of plane-of-sky measurements with an accuracy similar to that obtained today using VLBI tracking techniques. The second is optical ranging using active optical systems at both ends of the link, requiring a more careful design of the spacecraft optical communications system. One of the advantages of using optical frequencies is that they are not affected by charged particles in the signal path the way that radio frequencies are, eliminating solar plasma and ionospheric effects from the light-time calculation and the corresponding noise. On the other hand, clouds would preclude any type of optical communication, and daytime light scattering precludes astrometric measurements. This paper presents our analysis so far of the performance that could be achieved using optical data types in a number of deep-space scenarios. One of the questions that we are trying to answer is whether spacecraft equipped with optical communications terminals would also need to carry radio-frequency equipment for navigational purposes. We also want to understand how accurately we will be able to navigate spacecraft in different mission types and phases, and what would be the constraints, advantages, and disadvantages of using optical communications systems for deep-space navigation.

Karimi, Reza↗
DOE OSTI2025

Improved heavy-ion PID using scintillation light detector with neural network analysis: a Monte Carlo simulation study

The photon collection efficiency of gaseous scintillator detectors varies according to the position of the impinging charged particles in the medium that generates scintillation light. Thus, when impinging particles are distributed over a large area, the intrinsic photon-number resolution of the system is affected by a large variation. This work presents and discusses a method for adjusting the total number of detected photons to account for variation in the photon collection efficiency as a function of the position of the light source within the scintillating medium. The method was developed and validated by processing data from systematic simulation studies based on GEANT4 that model the response of the Energy Loss Optical Scintillation System (ELOSS) detector. The position of the charged particle is calculated using a deep neural network algorithm. This is accomplished by analyzing the distribution of scintillation light recorded by the array of photosensors. The estimated particle position is then used to calculate the correction factor and adjust the amount of captured light to account for variations in the photon collection efficiency. The neural network algorithm provides excellent tracking capabilities, achieving sub-millimeter position resolution and an angular resolution of 12 mrad, approaching the performance of traditional tracking detectors (e.g., drift chambers). The present method can be generalized to any optical scintillation system where the photon collection efficiency depends on the position of the impinging particle.

Heavy-ion detectors↗
NASA NTRS2008

Simulation of a Miniature, Low-Power Time-of-Flight Mass Spectrometer for In Situ Analysis of Planetary Atmospheres

We are implementing nano- and micro-technologies to develop a miniaturized electron impact ionization mass spectrometer for planetary science. Microfabrication technology is used to fabricate the ion and electron optics, and a carbon nanotube (CNT) cathode is used to generate the ionizing electron beam. Future NASA planetary science missions demand miniaturized, low power mass spectrometers that exhibit high resolution and sensitivity to search for evidence of past and present habitability on the surface and in the atmosphere of priority targets such as Mars, Titan, Enceladus, Venus, Europa, and short-period comets. Toward this objective, we are developing a miniature, high resolution reflectron time-of-flight mass spectrometer (Mini TOF-MS) that features a low-power CNT field emission electron impact ionization source and microfabricated ion optics and reflectron mass analyzer in a parallel-plate geometry that is scalable. Charged particle electrodynamic modeling (SIMION 8.0.4) is employed to guide the iterative design of electron and ion optic components and to characterize the overall performance of the Mini TOF-MS device via simulation. Miniature (less than 1000 cubic centimeters) TOF-MS designs (ion source, mass analyzer, detector only) demonstrate simulated mass resolutions greater than 600 at sensitivity levels on the order of 10(exp -3) cps/molecule N2/cc while consuming 1.3 W of power and are comparable to current spaceflight mass spectrometers. Higher performance designs have also been simulated and indicate mass resolutions approximately 1000, though at the expense of sensitivity and instrument volume.

King, Todd T.↗
DOE OSTI2023

Attosecond probing and control of charge migration in carbon-chain molecule

In quantum mechanics, when an electron is quickly ripped off from a molecule, a superposition of new eigenstates of the cation creates an electron wave packet that governs the charge flow inside, which has been called charge migration (CM). Experimentally, extracting such dynamics at its natural (attosecond) timescale is quite difficult. We report the first such experiment in a linear carbon-chain molecule, butadiyne (C 4 H 2 ), via high-harmonic spectroscopy (HHS). By employing advanced theoretical and computational tools, we showed that the wave packet and the CM of a single molecule are reconstructed from the harmonic spectra for each fixed-in-space angle of the molecule. For this one-dimensional molecule, we calculate the center of charge $\langle$ x $\rangle$ ( t ) to obtain v cm , to quantify the migration speed and how it depends on the orientation angle. The findings also uncover how the electron dynamics at the first few tens to hundreds of attoseconds depends on molecular structure. The method can be extended to other molecules where the HHS technique can be employed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Experimental demonstration of optical stochastic cooling

Particle accelerators and storage rings have been transformative instruments of discovery, and, for many applications, innovations in particle-beam cooling have been a principal driver of that success. Stochastic cooling (SC), one of the most important conceptual and technological advances in this area cools a beam through granular sampling and correction of its phase-space structure, thus bearing resemblance to a ‘Maxwell’s demon’. The extension of SC from the microwave regime up to optical frequencies and bandwidths has long been pursued, as it could increase the achievable cooling rates by three to four orders of magnitude and provide a powerful tool for future accelerators. First proposed nearly 30 years ago, optical stochastic cooling (OSC) replaces the conventional microwave elements of SC with optical-frequency analogues and is, in principle, compatible with any species of charged-particle beam. Here we describe a demonstration of OSC in a proof-of-principle experiment at the Fermi National Accelerator Laboratory’s Integrable Optics Test Accelerator. The experiment used 100-MeV electrons and a non-amplified configuration of OSC with a radiation wavelength of 950 nm, and achieved strong, simultaneous cooling of the beam in all degrees of freedom. This realization of SC at optical frequencies serves as a foundation for more advanced experiments with high-gain optical amplification, and advances opportunities for future operational OSC systems with potential benefit to a broad user community in the accelerator-based sciences.

43 PARTICLE ACCELERATORS↗
NASA NTRS1980

POLAR 5 - An electron accelerator experiment within an aurora. III - Evidence for significant spacecraft charging by an electron accelerator at ionospheric altitudes

The POLAR 5 rocket experiment carried an electron accelerator on a 'daughter' payload which injected a 0.1 A beam of 10 keV electrons in a pulsed mode every 410 ms. With spin and precession, injections were made over a wide range of pitch angles. Measurements from a double probe electric field instrument and from particle detectors on the 'mother' payload and from a crude RPA on the 'daughter' payload are interpreted to indicate that the 'daughter' charges to a potential between several hundred volts and 1 kV. The neutralizing return current to the 'daughter' is shown to be asymmetrically distributed with the majority being collected from the direction of the beam. The additional electrons necessary to neutralize the daughter are thought to be produced and heated through beam-plasma interactions postulated by Maehlum et al. (1980) and Grandal et al. (1980) to explain the particle and optical measurements. Significant electric fields emanating from the charged 'daughter' and the beam are seen at distances exceeding 100 m at the 'mother' payload.

Jacobsen, T. A.↗
NASA NTRS1985

Bevalac calibration of the SOFIE range and hodoscope detectors

The scintillating optical fiber isotope experiment (SOFIE) is a Cerenkov-dE/dx-Range experiment which was developed initially for balloon flight to study the isotopic composition of cosmic rays in the iron region. The electronic range and hodoscope detectors use scintillating optical fibers to image the tracks of stopping charged particles and to determine their trajectory. The particle range is determined and used together with a Cerenkov measurement to determine the mass of the stopping particle. Preliminary results of a Bevalac calibration performed in August, 1984 with a prototype of the balloon flight instrument, to study the measurement precision in range and trajectory which could be attained with this detector are described.

Binns, W. R.↗
NASA NTRSDate not supplied

Solar Absorptivity Degradation of Spacecraft Materials Due to UV and Charged Particles in the Gateway Environment

The Gateway Passive Thermal Control System (PTCS) Group has identified charged particle and UV degradation of Gateway materials as a knowledge gap for the Near Rectilinear Halo Orbit (NRHO) and transit environment. Candidate materials and coatings were subjected to expected mission UV and charged particle environments at NASA Goddard Space Flight Center (GSFC). In situ change in reflectivity was observed at specified intervals during testing such that change in solar absorptivity could be plotted as a function of time of solar exposure. Gateway will be an outpost in cislunar space designed to survive a 15-year mission to support human moon landings and future deep space exploration. The Gateway Passive Thermal Control System (PTCS) Group has identified charged particle and UV degradation of potential Gateway materials as a knowledge gap for the Near Rectilinear Halo Orbit (NRHO) and transit environment, especially the slow spiral transit planned for the first two modules. Solar absorptivity degradation is important to quantify because the end-of-life absorptivity impacts thermal performance of the system. To address this, ground testing is being completed at NASA Goddard Space Flight Center in which potential Gateway materials, including radiators, multi-layer insulation (MLI), and structural materials are subjected to the expected transit plus 15-year on-orbit charged particle fluence (9.86x1015 protons/cm2 at 2.5 keV and 3.1x1016 electrons/cm2 at 10 keV) and up to 5000 Equivalent Solar Hours (ESH). Reflectivity of a single sample of each material was measured in atmosphere and in vacuum inside the chamber after exposure to incremental levels of ESH and charged particle fluence. Increase in absorptivity of most samples were seen throughout the test including large differences in absorptivity of materials of the same category. Future testing will validate these results and include additional materials of interest.

materials in the space environment↗
DOE OSTI2024

Mechanical Detection of Nuclear Decays

We report the detection of individual nuclear alpha decays through the mechanical recoil of the entire micron-sized particle in which the decaying nuclei are embedded. Momentum conservation ensures that such measurements are sensitive to any particles emitted in the decay, including neutral particles that may otherwise evade detection with existing techniques. Detection of the minuscule recoil of an object more than 10^12 times more massive than the emitted particles is made possible by recently developed techniques in levitated optomechanics, which enable high-precision optical control and measurement of the mechanical motion of optically trapped particles. Observation of a change in the net charge of the particle coincident with the recoil allows decays to be identified with background levels at the micro-Becquerel level. Here, the techniques developed here may find use in fields ranging from nuclear forensics to dark matter and neutrino physics.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS2017

Experimental Setup for the Laboratory Investigation of Micrometeoroid Ablation Using a Dust Accelerator

A facility has been developed to simulate the ablation of micrometeoroids in laboratory conditions. An electrostatic dust accelerator is used to generate iron particles with velocities of 10-70 kilometers. The particles are then introduced into a chamber pressurized with a target gas, where the pressure is adjustable between 0.01 and 0.5 Torr, and the particle partially or completely ablates over a short distance. An array of biased electrodes above and below the ablation path is used to collect the generated ions/electrons with a spatial resolution of 2.6 centimeters along the ablating particles path, thus allowing the study of the spatiotemporal evolution of the process. For completely ablated particles, the total collected charge directly yields the ionization coefficient of a given dust material-target gas combination. The first results of this facility measured the ionization coefficient of iron atoms with N2, air, CO2, and He target gases for impact velocities greater than 20 kilometers per second, and are reported by Thomas et al. The ablation chamber is also equipped with four optical ports that allow for the detection of the light emitted by the ablating particle. A multichannel photomultiplier tube system is used to observe the ablation process with a spatial and temporal resolution of 0.64 centimeters and 90 nanoseconds. The preliminary results indicate that it is possible to calculate the velocity of the ablating particle from the optical observations, and in conjunction with the spatially resolved charge measurements allow for experimental validation of ablation models in future studies.

Thomas, Evan↗
DOE OSTI2024

Optical versus radiographic imaging and tomography: introduction to the ROADS feature issue

Optical imaging is an ancient branch of imaging dating back to thousands of years. Radiographic imaging and tomography (RadIT), including the first use of X-rays by Wilhelm Röntgen, and then, $γ$ -rays, energetic charged particles, neutrons, etc. are about 130 years young. The synergies between optical and radiographic imaging can be cast in the framework of these building blocks: Physics, Sources, Detectors, Methods, and Data Science, as described in Appl. Opt. 61, RDS1 (2022). Optical imaging has expanded to include three-dimensional (3D) tomography (including holography), due in to part the invention of optical (including infrared) lasers. RadIT are intrinsically 3D because of the penetrating power of ionizing radiation. Both optical imaging and tomography (OIT) and RadIT are evolving into even higher dimensional regimes, such as time-resolved tomography (4D) and temporarily and spectroscopically resolved tomography (4D + ). Further advances in OIT and RadIT will continue to be driven by desires for higher information yield, higher resolutions, and higher probability models with reduced uncertainties. Synergies in quantum physics, laser-driven sources, low-cost detectors, data-driven methods, automated processing of data, and artificially intelligent data acquisition protocols will be beneficial to both branches of imaging in many applications. These topics, along with an overview of the Radiography, Applied Optics, and Data Science virtual feature issue, are discussed here.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Nonlinear integrable optics beam dynamics experiment and diagnostics

All present circular particle accelerators are built around linear focusing optics. Un-avoidable nonlinear elements appear in accelerators, such as magnetic aberrations and space-charge effects, which are typically corrected using nonlinear magnets. However, these added nonlinearities degrade particle beam stability, and in most cases, the system becomes non-integrable. The Integrable Optics Test Accelerator (IOTA), at Fermi National Accelerator Laboratory (Fermilab), is a test bed to study beam dynamics in integrable lattices for both electron and proton beams, independently. This work presents experimental results of the nonlinear electron beam dynamics behavior in IOTA using an elliptical nonlinear magnet. The elliptical nonlinear magnet allows for a large betatron tune spread, allowing for a stable high-intensity beam. In a future experimental run, minimally invasive beam instrumentation is needed to study time-dependent collective instabilities, and halo formation in space-chargedominated proton beams. Traditional profile monitors are too destructive to the beam or just measure one dimension of the beam. A gas sheet can be injected perpendicular to theproton beam at an angle. By doing so, a two-dimensional, turn-by-turn, transverse profile measurement can be made, which will preserve the integrity of the beam. The developmentand progress of a gas sheet beam profile monitor will also be presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Optical and transport properties of plasma mixtures from ab initio molecular dynamics

Predicting the charged particle transport properties of warm dense matter/hot dense plasma mixtures is a challenge for analytical models. High accuracy ab initio methods are more computationally expensive, but can provide critical insight by explicitly simulating mixtures. In this work, we investigate the transport properties and optical response of warm dense carbon–hydrogen mixtures at varying concentrations under either conserved electronic pressure or mass density at a constant temperature. We compare options for mixing the calculated pure species properties to estimate the results of the mixtures. We find that a combination of the Drude model with the Matthiessen's rule works well for DC electron transport and low-frequency optical response. This breaks down at higher frequencies, where a volumetric mix of pure-species AC conductivities works better.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗