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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Exploring cosmic origins with CORE: Survey requirements and mission design

Future observations of cosmic microwave background (CMB) polarisation have the potential to answer some of the most fundamental questions of modern physics and cosmology, including: what physical process gave birth to the Universe we see today? What are the dark matter and dark energy that seem to constitute 95% of the energy density of the Universe? Do we need extensions to the standard model of particle physics and fundamental interactions? Is the ΛCDM cosmological scenario correct, or are we missing an essential piece of the puzzle? In this paper, we list the requirements for a future CMB polarisation survey addressing these scientific objectives, and discuss the design drivers of the COREmfive space mission proposed to ESA in answer to the "M5" call for a medium-sized mission. The rationale and options, and the methodologies used to assess the mission's performance, are of interest to other future CMB mission design studies. COREmfive has 19 frequency channels, distributed over a broad frequency range, spanning the 60–600 GHz interval, to control astrophysical foreground emission. The angular resolution ranges from 2' to 18', and the aggregate CMB sensitivity is about 2 μK∙arcmin. The observations are made with a single integrated focal-plane instrument, consisting of an array of 2100 cryogenically-cooled, linearly-polarised detectors at the focus of a 1.2-m aperture cross-Dragone telescope. The mission is designed to minimise all sources of systematic effects, which must be controlled so that no more than 10 -4 of the intensity leaks into polarisation maps, and no more than about 1% of E-type polarisation leaks into B-type modes. COREmfive observes the sky from a large Lissajous orbit around the Sun-Earth L2 point on an orbit that offers stable observing conditions and avoids contamination from sidelobe pick-up of stray radiation originating from the Sun, Earth, and Moon. The entire sky is observed repeatedly during four years of continuous scanning, with a combination of three rotations of the spacecraft over different timescales. With about 50% of the sky covered every few days, this scan strategy provides the mitigation of systematic effects and the internal redundancy that are needed to convincingly extract the primordial B-mode signal on large angular scales, and check with adequate sensitivity the consistency of the observations in several independent data subsets. COREmfive is designed as a "near-ultimate" CMB polarisation mission which, for optimal complementarity with ground-based observations, will perform the observations that are known to be essential to CMB polarisation science and cannot be obtained by any other means than a dedicated space mission. It will provide well-characterised, highly-redundant multi-frequency observations of polarisation at all the scales where foreground emission and cosmic variance dominate the final uncertainty for obtaining precision CMB science, as well as 2' angular resolution maps of high-frequency foreground emission in the 300–600 GHz frequency range, essential for complementarity with future ground-based observations with large telescopes that can observe the CMB with the same beamsize.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

Development of Bayesian analysis program for extraction of polarisation observables at CLAS

At the mass scale of a proton, the strong force is not well understood. Various quark models exist, but it is important to determine which quark model(s) are most accurate. Experimentally, finding resonances predicted by some models and not others would give valuable insight into this fundamental interaction. Several labs around the world use photoproduction experiments to find these missing resonances. The aim of this work is to develop a robust Bayesian data analysis program for extracting polarisation observables from pseudoscalar meson photoproduction experiments using CLAS at Jefferson Lab. This method, known as nested sampling, has been compared to traditional methods and has incorporated data parallelisation and GPU programming. It involves an event-by-event likelihood function, which has no associated loss of information from histogram binning, and results can be easily constrained to the physical region. One of the most important advantages of the nested sampling approach is that data from different experiments can be combined and analysed simultaneously. Results on both simulated and previously analysed experimental data for the K{sup +}Λ channel will be discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

The Heavy Photon Search experiment at Jefferson Laboratory

The Heavy Photon Search experiment (HPS) at Jefferson Laboratory will search for a new U(1) massive gauge boson, or "heavy-photon", mediator of a new fundamental interaction, called "dark-force", that couples to ordinary photons through kinetic mixing. HPS has sensitivity in the mass range 20 MeV – 1 GeV and coupling epsilon2 between 10 -5 and 10 -10 . The HPS experiment will look for the e+e- decay of the heavy photon, by resonance search and detached vertexing, in an electron beam fixed target experiment. HPS will use a compact forward spectrometer, which employs silicon microstrip detectors for vertexing and tracking, and a PbWO4 electromagnetic calorimeter for energy measurement and fast triggering.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

CeNTREX: a new search for time-reversal symmetry violation in the 205 Tl nucleus

The Cold molecule Nuclear Time-Reversal EXperiment (CeNTREX) is a new effort aiming for a significant increase in sensitivity over the best present upper bounds on the strength of hadronic time reversal (T) violating fundamental interactions. The experimental signature will be shifts in nuclear magnetic resonance frequencies of 205 Tl in electrically-polarized thallium fluoride (TlF) molecules. Here we describe the motivation for studying these T-violating interactions and for using TlF to do so. To achieve higher sensitivity than earlier searches for T-violation in TlF, CeNTREX uses a cryogenic molecular beam source, optical state preparation and detection, and modern methods of coherent quantum state manipulation. Details of the measurement scheme and the current state of the apparatus are presented, with quantitative measurements of the TlF beam. Lastly, the estimated sensitivity and methods to control systematic errors are discussed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2024

Exponential Improvements in the Simulation of Lattice Gauge Theories Using Near-Optimal Techniques

We report a first-of-its-kind analysis on post-Trotter simulation of U(1), SU(2), and SU(3) lattice gauge theories including fermions in arbitrary spatial dimension. We provide explicit circuit constructions as well as T-gate counts and logical qubit counts for Hamiltonian simulation. We find a reduction of up to 25 orders of magnitude in space-time volume over Trotter methods for simulations of non-Abelian lattice gauge theories relevant to the standard model. This improvement results from our algorithm having polynomial scaling with the number of colors in the gauge theory, achieved by utilizing oracle constructions relying on the sparsity of physical operators, in contrast to the exponential scaling seen in state-of-the-art Trotter methods, which employ explicit mappings onto Pauli operators. Our work demonstrates that the use of advanced algorithmic techniques leads to dramatic reductions in the cost of simulating fundamental interactions, bringing it in step with resources required for first-principles quantum simulation of chemistry.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Fundamental Studies of Adhesion of Dust to PV Module Surfaces: Chemical and Physical Relationships at the Microscale

Photovoltaic (PV) module soiling is a growing area of concern for performance and reliability. This paper provides evaluations of the fundamental interactions of dust/soiling particles with several PV module surfaces. The purpose is to investigate the basic mechanisms involving the chemistry, morphology, and resulting particle adhesion to the first photon-incident surface. The evaluation and mapping of the chemistry and composition of single dust particles collected from operating PV module surfaces are presented. The first correlated direct measurements of the adhesive force of individual grains from field-operating collectors on identical PV module glass are reported, including correlations with specific compositions. Special microscale atomic force microscopy techniques are adapted to determine the force between the particle and the module glass surface. Results are presented for samples under dry and moisture-exposed conditions, confirming the effects of cementation for surfaces having soluble mineral and/or organic concentrations. Additionally, the effects of hydrocarbon fuels on the enhanced bonding of soiling particles to surfaces are determined for samples from urban and highly trafficked regions. Comparisons between glass and dust-mitigating superhydrophobic and superhydrophilic coatings are presented. Potential limitations of this proximal probe technique are discussed in terms of results and initial proof-of-concept experiments.

14 SOLAR ENERGY↗
DOE OSTI2024

Peter Higgs (1929–2024)

Peter Ware Higgs, a particle physics icon, died on 8 April at the age of 94. Higgs illuminated the path to understanding how exact symmetries obeyed by the laws of nature might be masked by an asymmetric ground state that is an outcome of symmetrical laws. In 1964, he posited that a field filling all of space could be the agent that hides the underlying symmetries of the fundamental interactions. Additionally, when excited, the field reveals itself as a massive unstable particle. In the context of a joint theory of electromagnetism and the weak interaction, that particle—popularly called the Higgs boson—emerged as the keystone of the standard model of particle physics. The decades-long search for the boson engaged the passion of thousands of scientists and engineers and stirred the curiosity of the public the world over.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

On the extraction of cross sections for π{sup 0} and η photoproduction off neutrons from deuteron data

We discuss the procedure of extracting the photoproduction cross section for neutral pseudoscalar mesons off neutrons from deuteron data. The main statement is that the final-state-interaction corrections for the proton and neutron target are in general not equal, but for π{sup 0} production there are special cases where they have to be identical and there are large regions in the parameter space of incident photon energy and pion polar angle, Θ*, where they happen to be quite similar. The corrections for both target nucleons are practically identical for π0 production in the energy range of the Δ(1232)3/2+ resonance due to the specific isospin structure of this excitation. Also above the Δ-isobar range large differences between proton and neutron correction factors are only predicted for extreme forward angles (Θ* *lt; 20°), but the results are similar for larger angles. The case of η photoproduction is also briefly considered. Numerical results for the γp → π{sup 0}p and γn → π{sup 0}n correction factors are discussed. Also the model description for the available data on the differential γd → π{sup 0}pn cross sections are given.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2016

Elastic scattering of light nuclei through a simple potential model

The phase function method is adapted to deal with the scattering on our proposed interactions for α–α and α–{sup 3}He systems. The effect of the electromagnetic interaction is included in terms of a screened Coulomb potential. Based on our proposed potential models we present results for α–α and α–{sup 3}He elastic scattering phase shifts which compare well with more detailed calculations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

Towards a muon collider

A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work.

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Quantum information meets high-energy physics: input to the update of the European strategy for particle physics

Some of the most astonishing and prominent properties of Quantum Mechanics, such as entanglement and Bell nonlocality, have only been studied extensively in dedicated low-energy laboratory setups. The feasibility of these studies in the high-energy regime explored by particle colliders was only recently shown and has gathered the attention of the scientific community. For the range of particles and fundamental interactions involved, particle colliders provide a novel environment where quantum information theory can be probed, with energies exceeding by about 12 orders of magnitude those employed in dedicated laboratory setups. Furthermore, collider detectors have inherent advantages in performing certain quantum information measurements and allow for the reconstruction of the state of the system under consideration via quantum state tomography. Here, we elaborate on the potential, challenges, and goals of this innovative and rapidly evolving line of research and discuss its expected impact on both quantum information theory and high-energy physics.

Physics↗
DOE OSTI2020

Length scales and scale-free dynamics of dislocations in dense solid solutions

The fundamental interactions between an edge dislocation and a random solid solution are studied by analyzing dislocation line roughness profiles obtained from molecular dynamics simulations of Fe 0.70 Ni 0.11 Cr 0.19 over a range of stresses and temperatures. These roughness profiles reveal the hallmark features of a depinning transition. Namely, below a temperature-dependent critical stress, the dislocation line exhibits roughness in two different length scale regimes which are divided by a so-called correlation length. This correlation length increases with applied stress and at the critical stress (depinning transition or yield stress) formally goes to infinity. Above the critical stress, the line roughness profile converges to that of a random noise field. Motivated by these results, a physical model is developed based on the notion of coherent line bowing over all length scales below the correlation length. Above the correlation length, the solute field prohibits such coherent line bow outs. Using this model, we identify potential gaps in existing theories of solid solution strengthening and show that recent observations of length-dependent dislocation mobilities can be rationalized.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Ultrafast dynamics of electron-phonon coupling in a metal

In the past decade, the advent of time-resolved spectroscopic tools has provided a new ground to explore fundamental interactions in solids and to disentangle degrees of freedom whose coupling leads to broad structures in the frequency domain. Here, time- and angle-resolved photoemission spectroscopy (tr-ARPES) has been utilized to directly study the relaxation dynamics of a metal in the presence of electron-phonon coupling. The effect of photo-excitations on the real and imaginary part of the self-energy as well as the time scale associated with different recombination processes are discussed. In contrast with a theoretical model, the phonon energy does not set a clear scale governing quasiparticle dynamics, which is also different from the results observed in a superconducting material. These results point to the need for a more complete theoretical framework to understand electron-phonon interaction in a photo-excited state.

36 MATERIALS SCIENCE↗
DOE OSTI2020

SSA Monte Carlo and Master Equation Modeling of Neutron Leakage Distributions

Strongly stochastic neutron populations in highly subcritical multiplying media containing weak spontaneous fission sources are unique indicators of the presence of SNM. For instance, in neutron multiplicity counting, an extended tail in the count number probability distribution is observed that is a characteristic of and sensitive to the amount of SNM present. Theoretical modeling and efficient computation of stochastic neutron distributions are complementary to experimental measurements and moreover shed light on the fundamental interactions and transport processes that underlie nuclear signatures. Modeling approaches that are intermediate between gross-system level models and high-fidelity but computationally demanding Monte Carlo simulations are of particular interest in this regard. Furthermore we present three advances on existing work in point kinetic or lumped geometry: (i) implementation of the Stochastic Simulation Algorithm (SSA), a system state-updating Monte Carlo method that is more e cient than single-event Monte Carlo in lumped geometries, (ii) application of the backward Master equation to obtain time-gated count moments, and (iii) reconstructing the count number distribution from the deterministically computed moments using a generalized Laguerre polynomial expansion.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Nucleation, growth, and superlattice formation of nanocrystals observed in liquid cell transmission electron microscopy

This work reviews the advancements and prospects of liquid cell transmission electron microscopy (TEM) imaging and analysis methods in understanding the nucleation, growth, etching, and assembly dynamics of nanocrystals. The bonding of atoms into nanoscale crystallites produces materials with nonadditive properties unique to their size and geometry. The recent application of in situ liquid cell TEM to nanocrystal development has initiated a paradigm shift, (1) from trial-and-error synthesis to a mechanistic understanding of the “synthetic reactions” responsible for the emergence of crystallites from a disordered soup of reactive species (e.g., ions, atoms, molecules) and shape-defined growth or etching; and (2) from post-processing characterization of the nanocrystals’ superlattice assemblies to in situ imaging and mapping of the fundamental interactions and energy landscape governing their collective phase behaviors. Imaging nanocrystal formation and assembly processes on the single-particle level in solution immediately impacts many existing fields, including materials science, nanochemistry, colloidal science, biology, environmental science, electrochemistry, mineralization, soft condensed-matter physics, and device fabrication.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Magnets for Muon 6D Cooling Channels

The Helical Cooling Channel (HCC), an innovative technique for six-dimensional (6D) cooling of muon beams using a continuous absorber inside superconducting magnets, has shown considerable promise based on analytic and simulation studies. The implementation of this revolutionary method of muon cooling requires high field superconducting magnets that provide superimposed solenoid, helical dipole, and helical quadrupole fields. Novel magnet design concepts are required to provide HCC magnet systems with the desired fields for 6D muon beam cooling. New designs feature simple coil configurations that produce these complex fields with the required characteristics, where new high field conductor materials are particularly advantageous. The object of the program was to develop designs and construction methods for HCC magnets and design a magnet system for a 6D muon beam cooling channel. If successful the program would develop the magnet technologies needed to create bright muon beams for many applications ranging from scientific accelerators and storage rings to beams to study material properties and new sources of energy. Examples of these applications include energy frontier muon colliders, Higgs and neutrino factories, stopping muon beams for studies of rare fundamental interactions and muon catalyzed fusion, and muon sources for cargo screening for homeland security.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Compton Scattering Polarimetry for the Determination of the Proton's Weak Charge Through Measurements of the Parity-Violating Asymmetry of 1H(e,e')p

The Standard Model has been a theory with the greatest success in describing the fundamental interactions of particles. As of the writing of this dissertation, the Standard Model has not been shown to make a false prediction. However, the limitations of the Standard Model have long been suspected by its lack of a description of gravity, nor dark matter. Its largest challenge to date, has been the observation of neutrino oscillations, and the implication that they may not be massless, as required by the Standard Model. The growing consensus is that the Standard Model is simply a lower energy effective field theory, and that new physics lies at much higher energies. The Q weak Experiment is testing the Electroweak theory of the Standard Model by making a precise determination of the weak charge of the proton (Q p w ). Any signs of "new physics" will appear as a deviation to the Standard Model prediction. The weak charge is determined via a precise measurement of the parity-violating asymmetry of the electron-proton interaction via elastic scattering of a longitudinally polarized electron beam of an un-polarized proton target. The experiment required that the electron beam polarization be measured to an absolute uncertainty of 1%. At this level the electron beam polarization was projected to contribute the single largest experimental uncertainty to the parity-violating asymmetry measurement. This dissertation will detail the use of Compton scattering to determine the electron beam polarization via the detection of the scattered photon. I will conclude the remainder of the dissertation with an independent analysis of the blinded Q weak .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Scientific Computation Application Partnerships in Materials and Chemical Sciences, Charge Transfer and Charge Transport in Photoactivated Systems, Developing Electron-Correlated Methods for Excited State Structure and Dynamics in the NWChem Software Suite

Charge transfer and charge transport in photoactivated systems are fundamental processes that underlie solar energy capture, solar energy conversion, and photoactivated catalysis, both organometallic and enzymatic. We developed methods, algorithms, and software tools needed for reliable treatment of the underlying physics for charge transfer and charge transport, an undertaking with broad applicability to the goals of the fundamental-interaction component of the Department of Energy Office of Basic Energy Sciences and the exascale initiative of the Office of Advanced Scientific Computing Research.

14 SOLAR ENERGY↗