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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Electric Field Effects on the Hidden Order of Microstructured URu 2 Si 2

Despite being studied for over 30 years there is still continual interest in they heavy-fermion URu 2 Si 2 due largely in part to the still disagreed upon origin of the so-called hidden-order (HO) state that arises below THO = 17.5 K. While both the application of pressure and high magnetic fields have been shown to suppress the HO state, one mechanism that has yet to be explored is the application of an electric field, most likely due to the difficulty of measuring such an effect in a metal. To overcome this challenge we have used focused ion beam (FIB) lithography to obtain the necessary sample geometry to create an electric field across a small section of the sample by applying a voltage. Our results suggest that at low temperatures the application of an electric field is able to suppress the hidden order state.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Final Technical Report Project: Low-Energy Photonuclear Studies at HIGS and Lund

This report summarizes a program of low-energy photonuclear studies at MAX-Lab in Lund (Sweden) and at the High Intensity Gamma Source (HIGS) at Duke University. A major emphasis has been on Compton scattering from deuterium in order to determine the electric and magnetic polarizabilities of the neutron. The studies at Lund utilized unpolarized photons at Egamma = 62-115 MeV to measure differential cross sections. The studies at HIGS utilized polarized and unpolarized photon beams (both linear and circular) at Egamma < 90 MeV. Polarization observables will be exploited to improve our understanding of the electric and magnetic polarizabilities, and in particular, double-polarization observables (using polarized targets) will be measured in the future to provide new information about the spin polarizabilities of the nucleon. The MAX-Lab experiments (using unpolarized photons) focused on an approved PAC proposal for Compton scattering on the deuteron aimed at making a precise determination of the electromagnetic polarizabilities of the neutron. At MAX-Lab we had three of the largest NaI detectors in the world, each capable of ~2% energy resolution. We have completed our measurements in two separate tagged photon energy ranges which overlap each other (62-97 MeV and 90-115 MeV) and the results of these experiments have been published. The photon beam at the High Intensity Gamma Source (HIGS) has several distinct advantages that make it unique: (1) ultra-high photon flux, ultimately reaching 100 MHz, (2) 100% linearly polarized photon beam, as well as circular polarization, (3) monoenergetic beam, with ~2% energy resolution, and (4) extremely low-background beam environment. Exploiting the high flux and polarization capabilities of the HIGS photon beam is central in the series of experiments being performed at this facility. Very little data exist on Compton scattering using polarized photons. We will exploit clear sensitivities in the polarization observables to the electric and magnetic polarizabilities of the nucleon, and we will ultimately extend these studies to the investigation of the spin polarizabilities. To accomplish these objectives, a liquid hydrogen/deuterium/helium cryotarget has been constructed at HIGS, and an array of NaI detectors has been commissioned for Compton studies.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Summary of recent experiments on focusing of target-normal-sheath-accelerated proton beam with a stack of conducting foils

We present a summary of recent experiments on focusing of laser target-normal-sheath-accelerated (TNSA) proton beam with a stack of thin conducting foils. The experiments were performed using the Phelix laser (GSI-Darmstadt) and the Titan laser, Lawrence Livermore National Laboratory. The phenomena consistent with self-collimation (or weak self-focusing) of TNSA protons were experimentally observed for the first time at the Phelix laser user facility, in a specially engineered structure ('lens') consisting of a stack of 300 thin aluminum foils separated by 50 μm vacuum gaps. Follow up experiments using the Titan laser obtained results consistent with the collimation/focusing observed in the initial experiments using the Phelix. The Titan experiments employed improved, 25 μm- and 50 μm-gap targets and the new fine mesh diagnostic. All the experiments were carried out in a “passive environment,” i.e., no external fields were applied, and no neutralization plasma or injection of secondary charged particles was imposed. A plausible interpretation of the observed phenomena is that the combination of magnetic self-pinch forces generated by the beam current together with the simultaneous reduction of the repulsive electrostatic forces due to the conducting foils inhibits radial expansion of the beam.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Assembly of the MOLLER Toroidal Magnets at Jefferson Lab

The MOLLER experiment at the Thomas Jefferson National Accelerator Facility (JLab) aims to precisely measure the weak interaction between electrons. This experiment leverages the 12 GeV electron beam and will run for three years. A crucial component of MOLLER is a system of five uniquely shaped water-cooled toroidal magnets. These magnets, possessing seven-fold symmetry, are designed to focus particles by separating electrons scattered off hydrogen in a liquid hydrogen target. The five magnets separate electrons scattered off electrons (Møller scattering) and protons (elastic e-p scattering) within target into approximately circular rings at the detector. Here, this paper presents the assembly process for these five toroidal magnets, detailing critical steps including epoxy application, pin insertion, soldering and brazing, coil assembly, and alignment, all performed to meet stringent magnet specifications. Additionally, it discusses challenges encountered during construction and highlights lessons learned, offering insights for future magnet development projects.

Lamont, Joseph [Thomas Jefferson National Accelera↗
DOE OSTI2011

Variable Gap Undulator for 1.5-48 Kev Free Electron Laser at Linac Coherent Light Source

We study the feasibility of generating femtosecond duration Free-Electron Laser with a variable photon energy from 1.5 to 48 keV, using an electron bunch with the same characteristics of the LINAC Coherent Light Source (LCLS) bunch, and a planar undulator with additional focusing. We assume that the electron bunch energy can be changed, and the undulator has a variable gap, allowing a variable undulator parameter. It is assumed to be operated in an ultra-low charge and ultra-short pulse regime. We study the feasibility of a tunable, short pulse, X-ray FEL with photon energy from 1.5 to 48 keV, using an electron beam like the one in the LCLS and a 2:5 cm period, variable gap, planar undulator. The beam energy changes from 4.6 to 13.8 GeV, the electorn charge is kept at 10 pC, and the undulator parameter varies from 1 to 3. The undulator length needed to saturate the 48 keV FEL is about 55 m, with a peak power around 5 GW. At longer wavelength the saturation length is as short as 15 m, and the peak power around 20 GW. The results from the analytical models and the GENESIS simulations show that the system is feasible. The large wavelength range, full tunability and short, few femtosecond pulses, together with the large peak power, would provide a powerful research tool.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

Materials, Strands, and Cables for Superconducting Accelerator Magnets. Final Report

This report focuses on Materials, Strands and Cables for High Energy Physics Particle accelerators. In the materials area, work has included studies of basic reactions, diffusion, transformations, and phase assemblage of Nb 3 Sn. These materials science aspects have been married to results, in the form of flux pinning, B c2 , B irr , and transport J c , with an emphasis on obtaining the needed J c for HEP needs. Attention has also been paid to the “intermediate-temperature superconductor”, magnesium diboride emphasis being placed on (i) irreversibility field enhancement, (ii) critical current density and flux pinning, and (iii) connectivity. We also report on studies of Bi-2212. The second area of the program has been in the area of “Strands” in which, aside from the materials aspect of the conductor, its physical properties and their influence on performance have been studied. Much of this work has been in the area of magnetization estimation and flux jump calculation and control. One of the areas of this work was strand instabilities in high-performance Nb 3 Sn conductors due to combined fields and currents. Additionally, we investigated quench and thermal propagation in YBCO coated conductors at low temperatures and high fields. The last section, “Cables”, focussed on interstrand contact resistance, ICR, it origins, control, and implications. Following on from earlier work in NbTi, the present work in Nb 3 Sn has aimed to make ICR intermediate between the two extremes of too little contact (no current sharing) and too much (large and unacceptable magnetization and associated beam de-focussing). Interstrand contact and current sharing measurements are being made on YBCO based Roebel cables using transport current methods. Finally, quench was investigated for YBCO cables and the magnets wound from them, presently with a focus on 50 T solenoids for muon collider applications.

43 PARTICLE ACCELERATORS↗
NASA NTRS1975

Plasma phenomena at magnetic neutral points

A model of the plasma focus is considered, in which large axial electric fields are induced by the imploding current sheet during the final few nanoseconds of the collapse phase. This field provides a mechanism for creation of a beam of electrons of highly suprathermal energies. For this beam, the bremsstrahlung radiation is calculated, which is expected either from electron-deuteron collisions in the focused plasma itself or from the beam as it reaches the walls of the device. Comparison with experimental results indicates that the walls are the more likely source of these hard X-rays and also find qualitative agreement of the expected angular distribution of X-rays with experiment.

Sturrock, P. A.↗
DOE OSTI2018

Muon Beam Dynamics and Spin Dynamics in the g-2 Storage Ring

The goal of the new g-2 experiment at fermilab is a measurement of the anomalous magnetic moment of the muon, with uncertainty of less than 140 ppb. The experimental method is to store a beam of polarized muons in a storage ring with pure vertical dipole field and electrostatic focusing, and to measure the precession frequency. Control of the systematics depends on unprecedented knowledge of the details of the phase space of the muon distribution. That knowledge is derived from direct measurements with scintillating fiber detectors that are inserted into the muon beam for diagnostic measurements, traceback straw tube tracking chambers, as well as the calorimeters that measure energy, time and position of the decay positrons. The interpretation of the measurements depends on a detailed model of the storage ring guide field. This invited talk presents results of studies of the distribution from the commissioning run of the experiment.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Summary of Jefferson Lab LDRD on FFA@CEBAF Beam Dynamics Simulations

As Thomas Jefferson National Accelerator Facility (Jefferson Lab) looks toward the future, we are considering expanding our energy reach by using Fixed-Field Alternating Gradient (FFA) technology. Significant efforts have been made to design a hybrid accelerator which combines conventional recirculating electron LINAC design with permanent magnet-based FFA technology to increase the number of beam recirculations, and thus the energy. In an effort to further this progress, Jefferson Lab awarded a Laboratory Directed Research and Development (LDRD) grant to focus not on the design, but on detailed simulations of the designs created by the larger collaboration. This document will summarize the work performed during this LDRD, and direct the reader to other proceedings which describe elements of the work in greater detail.

Deitrick, K.↗
DOE OSTI2016

On the utility of non thermal plasmas

Nonthermal plasmas have properties which can differ substantially even from thermal plasmas of the same density and energy. In practical applications, many of these differences have utility that can be exploited, often with waves. The goal of this thesis is to explore three such applications of nonthermal plasma for the purposes of wave amplification and, ultimately, controlled nuclear fusion. First, we discuss the outstanding potential for a shaped plasma technology that relies on ionizing a beam of aerosol particles. This ionization results in a Coulomb explosion, yielding a highly nonthermal distribution for the plasma in the target volume. Homogeneous, high aspect ratio plasma couplers such as these could be used in a Raman amplification scheme to attain the next generation of laser intensities. Such a powerful laser could be used to study radiation reaction and vacuum pair production, among many other applications. We describe the conditions under which sufficiently dense aerosol beams can be prepared and provide some experimental validation of these claims. Second, we survey the prospects for controlled p-11B fusion in both magnetic and inertial confinement schemes. Whereas most studies have focused on mitigating the bremsstrahlung loss channel, we focus on nonthermal manipulations of the bulk plasma which could improve the reactivity. In particular, we present upper bounds on the p-11B reactivity using alpha channeling to efficiently heat the proton distribution in both schemes. Finally, we place a sharp limit on the energy that can be extracted from a non-thermal particle distribution using waves. In the quasilinear regime of wave-particle interaction, waves rearrange the densities of states in phase space in a diffusive fashion. A salient consequence is that only certain, generally nonthermal, plasma states can be reached. We characterize this restricted state space and thereby reduce the problem of maximizing energy extraction to linear programming. Varying the connectedness of the phase space so that e.g. particles may only be diffused to parts of phase space close in energy, we describe the implications for the state space and the solution of the optimization problem.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2018

Superconducting ECR ion source: From 24-28 GHz SECRAL to 45 GHz fourth generation ECR

The development of superconducting ECR source with higher magnetic fields and higher microwave frequency is the most straight forward path to achieve higher beam intensity and higher charge state performance. SECRAL, a superconducting third generation ECR ion source, is designed for 24-28 GHz microwave frequency operation with an innovative magnet configuration of sextupole coils located outside the three solenoids. SECRAL at 24 GHz has already produced a number of record beam intensities, such as 40 Ar 12+ 1.4 emA, 129 Xe 26+ 1.1 emA, 129 Xe 30+ 0.36 emA, and 209 Bi 31+ 0.68 emA. SECRAL-II, an upgraded version of SECRAL, was built successfully in less than 3 years and has recently been commissioned at full power of a 28 GHz gyrotron and three-frequency heating (28 + 45 + 18 GHz). New record beam intensities for highly charged ion production have been achieved, such as 620 eμA 40 Ar 16+ , 15 eμA 40 Ar 18+ , 146 eμA 86 Kr 28+ , 0.5 eμA 86 Kr 33+ , 53 eμA 129 Xe 38+ , and 17 eμA 129 Xe 42+ . Recent beam test results at SECRAL and SECRAL II have demonstrated that the production of more intense highly charged heavy ion beams needs higher microwave power and higher frequency, as the scaling law predicted. A 45 GHz superconducting ECR ion source FECR (a first fourth generation ECR ion source) is being built at IMP. FECR will be the world's first Nb 3 Sn superconducting-magnet-based ECR ion source with 6.5 T axial mirror field, 3.5 T sextupole field on the plasma chamber inner wall, and 20 kW at a 45 GHz microwave coupling system. This paper will focus on SECRAL performance studies at 24-28 GHz and technical design of 45 GHz FECR, which demonstrates a technical path for highly charged ion beam production from 24 to 28 GHz SECRAL to 45 GHz FECR.

47 OTHER INSTRUMENTATION↗
NASA NTRS1978

Compact electron-beam source for formation of neutral beams of very low vapor pressure materials

In order to form metal vapors for neutral beam studies, an electron-beam heater and a power supply have been designed. The source, which measures about 30 x 50 x 70 mm, consists of a filament, accelerating plate (defined by pole pieces), and a supported target. The electrons from the filament are focused by the field penetration through a 2 mm slit in the high-voltage cage. They are then accelerated to about 5 kV to a ground plate. The electrons then follow a path in the magnetic field and strike the sample to be heated on its front surface. The assembly is attached to a water-cooled base plate. The electron beam source has produced beams of Ta and C particles with densities of about 10 to the 8th power/cu cm.

Rutherford, J. A.↗
DOE OSTI2016

DCS - A high flux beamline for time resolved dynamic compression science – Design highlights

The Dynamic Compression Sector (DCS) beamline, a national user facility for time resolved dynamic compression science supported by the National Nuclear Security Administration (NNSA) of the Department of Energy (DOE), has recently completed construction and is being commissioned at Sector 35 of the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The beamline consists of a First Optics Enclosure (FOE) and four experimental enclosures. A Kirkpatrick–Baez focusing mirror system with 2.2 mrad incident angles in the FOE delivers pink beam to the experimental stations. A refocusing Kirkpatrick–Baez mirror system is situated in each of the two most downstream enclosures. Experiments can be conducted in either white, monochromatic, pink or monochromatic-reflected beam mode in any of the experimental stations by changing the position of two interlocked components in the FOE. The beamline Radiation Safety System (RSS) components have been designed to handle the continuous beam provided by two in-line revolver undulators with periods of 27 and 30 mm, at closed gap, 150 mA beam current, and passing through a power limiting aperture of 1.5 x 1.0 mm{sup 2}. A novel pink beam end station stop [1] is used to stop the continuous and focused pink beam which can achieve a peak heat flux of 105 kW/mm{sup 2}. A new millisecond shutter design [2] is used to deliver a quick pulse of beam to the sample, synchronized with the dynamic event, the microsecond shutter, and the storage ring clock.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

The dipole corrector magnets for the FFAG beam line of the CBETA accelerator

The Cornell Brookhaven Experimental Test Reactor (CBETA) is a novel, and the first of its kind accelerator to combine two remarkable concepts, the Energy Recovery Linac (ERL) and the Fixed Field Alternating Gradient (FFAG) concept. The accelerator has been built at Cornell University in collaboration with Brookhaven National Laboratory (BNL) and it is at its commissioning stage. The FFAG beam line consist of two arcs sections and a straight section, with all sections comprised of single cells, each cell made of two Halback type of magnets. The cell in the arc consists of one focusing quadrupole and a combined function magnet which is comprised of a dipole and a defocusing quadrupole multipole. The cells in the straight section consist of a focusing and a defocusing quadrupoles. Each focusing quadrupole has a window-frame dipole corrector magnet generating vertical dipole field and the other magnet has a corrector generating horizontal dipole field. This technical note reports on the mechanical design and the electromagnetic properties of these window frame corrector magnets.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Compact microwave ion source for industrial applications

A 2.45 GHz microwave ion source for ion implanters has many good properties for industrial application, such as easy maintenance and long lifetime, and it should be compact for budget and space. But, it has a dc current supply for the solenoid and a rf generator for plasma generation. Usually, they are located on high voltage platform because they are electrically connected with beam extraction power supply. Using permanent magnet solenoid and multi-layer dc break, high voltage deck and high voltage isolation transformer can be eliminated, and the dose rate on targets can be controlled by pulse duty control with semiconductor high voltage switch. Because the beam optics does not change, beam transfer components, such as focusing elements and beam shutter, can be eliminated. It has shown the good performances in budget and space for industrial applications of ion beams.

43 PARTICLE ACCELERATORS↗
DOE OSTI2026

Induced Magnetic Fields in LBNF Horns and DUNE-PRISM Off-Axis Neutrinos

Deep Underground Neutrino Experiment (DUNE) is a next-generation, long-baseline neutrino oscillation experiment that will utilize an intense neutrino beam from Fermilab to measure neutrino oscillation parameters with unprecedented precision. The DUNE-PRISM near detector concept employs an off-axis measurement strategy to mitigate neutrino-nucleus interaction uncertainties; however, this approach relies critically on the accurate characterization of the neutrino flux. As statistical uncertainties are suppressed in the high-intensity Long Baseline Neutrino Facility (LBNF) beam, beamline focusing uncertainties, specifically those arising from focusing horn geometry, become an important systematic uncertainty source. This work presents Geant4 LBNF beam simulations quantifying one of the most important systematic uncertainties for off-axis fluxes: the impact of manufacturing tolerances in the LBNF horns. The focusing horns consist of coaxial inner and outer conductors. Ideally, the region inside the inner conductor is field-free, while the region between the inner and outer conductors serves as the focusing region, where the magnetic field follows a nominal $1/r$ dependence. However, inner conductor deformations such as eccentricity and ellipticity introduce asymmetry, inducing unintended magnetic fields inside the field-free region. Crucially, while the on-axis neutrino flux remains largely unaffected by these induced fields, the resulting flux fractional shifts become pronounced over a particular range of off-axis positions where the DUNE-PRISM program will perform measurements. Consequently, these inner conductor deformations can impact the precision of flux predictions, which could potentially degrade the sensitivity to oscillation parameters. Possible mitigation strategies for these effects will also be presented.

Bae, Yuri [U. Minnesota, Minneapolis (main)] (ORCI↗
DOE OSTI2018

Additive Manufacturing: A New Paradigm for the Next Generation of High-Power-Density Direct-Drive Electric Generators

In recent years, there has been a growing demand for high-power-density direct-drive generators in the wind industry owing to their high reliability, torque per unit volume, and conversion efficiencies. However, direct-drive wind turbine generators are very large, low-speed electric machines, which pose remarkable design and manufacturing issues that challenge their upscaling potential and cost of implementation. With air-gap tolerance as the main design driver, the need for high stiffness shifts the focus toward support-structure design that forms a significant portion of the generator's total mass. Existing manufacturing processes allow the use of segmented-steel-weldment disk or spoke-arm assemblies that yield stiffer structures per unit mass but tend to be heavier and more expensive to build. As a result, there is a need for a transformative approach to realize lightweight designs that can also facilitate series production at competitive costs. Inspired by recent developments in metal additive manufacturing (AM), we explore a new freedom in the structural design space with a high potential for weight savings in direct-drive generators. This includes the feasibility of using nonconventional complex geometries, such as lattice-based structures as structurally efficient options. Powder-binder jetting of a sand-cast mold was identified as the most feasible AM technology to produce large-scale generator rotor structures with complex geometry. A parametric optimization study was performed and optimized results within deformation and mass constraints were found for each design. The response to the maximum Maxwell stress due to unbalanced magnetic pull was also explored for each design. Further, a topology optimization was applied for each parameter-optimized design to validate results and provide insights into further mass reduction. These novel designs catered for AM are compared in both deflection and mass to conventional rotor designs using NREL's systems engineering design tool, GeneratorSE. The optimized lattice design with a U-beam truss resulted in a 24% reduction in structural mass of the rotor and 60% reduction in radial deflection. It is demonstrated that additive manufacturing shifts the focus from manufacturability constraints toward lower mass.

17 WIND ENERGY↗
DOE OSTI2012

Magneto-optical magnetometry of individual 30 nm cobalt nanowires grown by electron beam induced deposition

We show that magnetometry measurements based upon the magneto-optical Kerr effect and high resolution optical microscopy can be used as a noninvasive probe of magnetization reversal for individual nano-structures. Our measurements demonstrate single pass hysteresis loop measurements for sample sizes down to 30 nm width. A quantitative signal-to-noise ratio evaluation shows that our approach achieves an at least 3-fold improvement in sensitivity if compared to focused laser based nano-magnetometry. An analysis of the physical limits of our detection scheme enables us to estimate that measurements for structures with single digit nm widths and magnetic moments of 10{sup -16} Am{sup 2} are feasible.

36 MATERIALS SCIENCE↗