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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Measurements of beam backgrounds in SuperKEKB Phase 2

The high design luminosity of the SuperKEKB electron-positron collider will result in challenging levels of beam-induced backgrounds in the interaction region. Understanding and mitigating these backgrounds is critical to the success of the Belle II experiment. We report on the first background measurements performed after roll-in of the Belle II detector, utilizing both the BEAST II system of dedicated background sensors and the Belle II detector itself. Here we also report on first revisions to the background simulation made in response to our findings. Backgrounds measured include contributions from synchrotron radiation, beam-gas, Touschek, and injection backgrounds. At the end of Phase 2, single-beam backgrounds originating from the 4 GeV positron Low Energy Ring (LER) agree reasonably well with simulation, while backgrounds from the 7 GeV electron High Energy Ring (HER) are approximately one order of magnitude higher than simulation. We extrapolate these backgrounds forward and conclude it is safe to proceed to installation of the Belle II vertex detector.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

In situ transmission electron microscopy with dual ion beam irradiation and implantation

To study the helium effects and their interactions with displacement damage in irradiated materials, an in situ dual-ion beam irradiation capability with transmission electron microscopy was recently established at the IVEM-Tandem Facility at Argonne National Laboratory. Pure nickel was irradiated in situ individually with 1 MeV Kr ions for displacement damage study, 16 keV He ions for helium implantation, and simultaneously with 1 MeV Kr ions and 16 keV He ions at the rate of 1 at.% He/dpa to study the interaction of helium and displacement damage at 500 degrees C. Helium bubbles were formed and segregated within dislocation loops during the He implantation experiment and no bubbles were observed outside the loops. The loop size increased with increasing helium concentration. In contrast, helium bubbles were formed uniformly in the matrix when nickel was irradiated simultaneously with 1 MeV Kr ions and 16 keV He ions. Overall, it is suggested that the uniformly-distributed defect clusters formed under 1 MeV Kr ion irradiation serve as trapping sites of helium atoms resulting in homogeneous nucleation of helium bubbles under the dualion beam irradiation in nickel.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Ring-based electron cooler for EIC

An Electron Ion Collider (EIC) at Brookhaven National Laboratory (BNL) is being proposed as a new discovery machine for the nuclear physics and quantum chromodynamics. The hadron beam cooling plays an important role in the EIC machine to achieve its physics goals. The most challenging is cooling of protons at the highest energy in the EIC. In this paper, we present a possible design of a ring-based electron cooler for the high energy hadron beam cooling. In proposed approach, the electrons will cool the hadrons while being cooled themselves by radiation damping in the storage ring. For design of the cooler using storage ring approach several aspects becomes very important, including electron ring optics design, chromaticity correction, calculate the dynamic aperture, radiation damping, quantum excitation, and intrabeam scattering (IBS). In addition, such effects as beam-beam scattering (BBS) due to interaction of electrons with hadrons become of special concern. In this paper, we discuss and take into design all the effects above, as well as introduce generalized treatment of the BBS and 3-D quantum lifetime. A special feature of our design is an effective use of dispersion in the cooling section, both for the ions and electrons, to redistribute the cooling rate between the longitudinal and horizontal planes. Finally, the cooling performance is simulated for proton beam at the top energy of the EIC. Our conclusion is that such ring-based cooler could be a feasible approach to provide required parameters of hadron beam at the top energy of 275 GeV for the EIC.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Cross Section Results from the MicroBooNE Experiment

The MicroBooNE detector is currently the largest operating liquid argon neutrino experiment in the world. Located at the Fermi National Accelerator Laboratory (Fermilab), MicroBooNE has been collecting both electron neutrino (\(\nu _{e}\)) and muon neutrino (\(\nu _{\mu }\)) interactions from both the Booster Neutrino Beam (BNB) and the Neutrino Main Injector (NuMI) since late 2015. During this time, MicroBooNE has measured a wide-variety of interaction topologies including \(\nu _{\mu }\) charged current, \(\nu _{e}\) charged current, resonant \(\pi ^{0}\), and various high multiplicity interactions. To date, many of MicroBooNE’s measurements are either the first of their kind using liquid argon as a target material, or have the largest number of events collected using a liquid argon detector. All of these measurements combine to form a rich cross section programme, aiming to enhance understanding of GeV-range neutrino interaction on liquid argon for upcoming detectors such as SBND, ICARUS, and DUNE.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Amplification of laser imprint in the presence of strong, externally imposed, target-normal magnetic fields

Here, an experiment was performed on the OMEGA EP Laser System to investigate the effects of magnetic fields on laser imprint. A 30 µ⁢m thick CH target was driven by a single beam delivering 3.0 kJ of UV energy in a 5 ns square pulse without smoothing by spectral dispersion. The Rayleigh-Taylor amplification of this beam's imprint on the target surface was monitored using face-on gated x-ray radiography from a Gd backlighter. Magnetic fields of up to 45 T were applied normal to the target surface. Analysis of the resulting radiographs shows a 60 ± 13% increase in the spectrally resolved surface perturbation amplitudes, consistent at all times and for all unsaturated frequencies. This consistency indicates that the increase in perturbation amplitudes was due to a change in the initial amplitudes rather than Rayleigh-Taylor growth. This is supported by the trajectory of individual modes and the inferred time-averaged perturbation growth rates. Laser imprint is therefore inferred to have increased due to strong magnetic fields that remain in the conduction zone of the target, suppressing off-axis electron motion and limiting the effects of thermal smoothing.

direct drive↗
DOE OSTI2026

Comparisons of triple-differential cross sections for quasielastic-like $ν_μ$-hydrocarbon interactions using $\langle E_ν\rangle \sim$ 3~GeV versus $\sim$ 6~GeV beams in MINERvA

Neutrino charged-current quasielastic-like scattering, a reaction category extensively used in neutrino oscillation measurements, receives contributions from single nucleon knockout processes, multinucleon processes, and inelastic scattering with subsequent rescattering or absorption in the nucleus to produce only nucleons in the final state. In this article, comparisons are presented of the same measurement in two different wideband neutrino beams: one beam peaks near 3 GeV with few neutrinos above 6 GeV; the other peaks near 6 GeV with few neutrinos above 10 GeV. Comparisons of differential cross sections in muon and proton kinematics for these two exposures probe deviations from free-neutron scattering that arise from the processes involving the nuclear medium, and provide a test of neutrino interaction models used to infer neutrino energies in oscillation experiments. Discrepancies are observed between the data and predictions that point to overestimates of the final state interactions of both protons and charged pions in quasielastic-like events.

Ruterbories, D. [Rochester U.]↗
DOE OSTI2026

Developing New Beam Constraints to Improve Sterile Neutrino Searches at NOvA

NOvA is a long-baseline neutrino oscillation experiment utilizing two functionally identical liquid scintillator detectors located 14 mrad off-axis from the NuMI beam at Fermilab. The position of the Near Detector (ND), 1 km from the neutrino production target, means it sees a range of off-axis angles (12.6-17.2 mrad), resulting in a noticeable energy gradient across the detector face. In addition, the neutrino production points vary widely along the decay pipe, which leads to a distribution of true neutrino baselines (L), and limits the sensitivity of our current sterile neutrino searches. This work presents a new "baseline reconstruction" technique designed to exploit our off-axis position to triangulate the precise origin of neutrinos within the NuMI beamline. By projecting the total momentum vector of Charged Current (CC) and Neutral Current (NC) interactions back to the central beam axis, we estimate the individual baseline for each event. We describe the technique, evaluate its performance, and demonstrate how this can improve the sensitivity of future searches for sterile neutrinos through reduced flux systematic uncertainties and improved L/E resolution.

Burns, Jessica [Cincinnati U.]↗
DOE OSTI2025

Enhanced Isomer Population via Direct Irradiation of Solid-Density Targets Using a Compact Laser-Plasma Accelerator

Excitation of long-lived states in bromine nuclei using a tabletop laser-plasma accelerator providing pulsed (<100 fs) electron beams provided a sensitive probe of γ strength and level densities in the nuclear quasicontinuum and may indicate angular momentum coupling through electron-nuclear interactions. Solid-density active $LaBr_{3}$ targets absorb real and virtual photons up to 35 ± 2.5 MeV and deexcite through γ cascade into different states. Here, a factor of 4.354 ± 0.932 enhancement of the $^{80}Br^{m}/^{80}Br^{g}$ isomeric ratio was observed following electron irradiation, as compared to bremsstrahlung. Additional angular momentum transfer could possibly occur through nuclear-plasma or electron-nuclear interactions enabled by the ultrashort electron beam. Further investigation of these mechanisms could have far-reaching impact including decreased storage of long-term nuclear waste and an improved understanding of heavy element formation in astrophysical settings.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Measurement of Beam-Correlated Background Neutrons from the Fermilab Booster Neutrino Beam in ANNIE Phase-I

The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) aims to make a unique measurement of neutron yield from neutrino-nucleus interactions and to perform R&D for the next generation of water-based neutrino detectors. In this paper, we characterize beam-induced neutron backgrounds in the experimental hall at Fermi National Accelerator Laboratory. It is shown that the background levels are sufficiently low to allow the next stage of the experiment to proceed. These measurements are relevant to other Booster Neutrino Beam (BNB) [1] experiments located adjacent to ANNIE Hall, where dirt neutrons and sky-shine could present similar backgrounds.

Particle identification methods↗
DOE OSTI2021

Adaptive machine learning for time-varying systems: low dimensional latent space tuning

Machine learning (ML) tools such as encoder-decoder convolutional neural networks (CNN) can represent incredibly complex nonlinear functions which map between combinations of images and scalars. For example, CNNs can be used to map combinations of accelerator parameters and images which are 2D projections of the 6D phase space distributions of charged particle beams as they are transported between various particle accelerator locations. Despite their strengths, applying ML to time-varying systems, or systems with shifting distributions, is an open problem, especially for large systems for which collecting new data for re-training is impractical or interrupts operations. Particle accelerators are one example of large time-varying systems for which collecting detailed training data requires lengthy dedicated beam measurements which may no longer be available during regular operations. We present a novel method of adaptive ML for time-varying systems. Our approach is to map very high (N ≈ 100k) dimensional inputs (a combination of scalar parameters and images) into the low dimensional (N ≈ 2) latent space at the output of the encoder section of an encoder-decoder CNN. We then actively tune the low dimensional latent space-based representation of complex system dynamics by the addition of an adaptively tuned feedback vector directly before the decoder sections builds back up to our image-based high-dimensional phase space density representations. This method allows us to learn correlations within and to quickly tune the characteristics of incredibly large parameter space systems and to track their evolution in real time based on feedback without massive new data sets for re-training. We demonstrate that our method can accurately predict and track the phase space of charged particle beams at various locations in a particle accelerator by adaptively adjusting in real-time while the unknown input beam distribution of the accelerator is changing in shape, charge, and offset and while the RF system of the accelerator itself is also changing in an unpredictable way. For FACET-II we demonstrate that such an approach has the potential to use transverse deflecting cavity and energy spread spectrum beam measurements to accurately predict 2D projections of the 6D phase space of the electron beam at the plasma wakefield acceleration interaction point where such diagnostics are unavailable.

47 OTHER INSTRUMENTATION↗
DOE OSTI2024

Measurement of γ -ray production via the neutron- O 16 reaction using a 77 MeV quasimonoenergetic neutron beam

Understanding of γ-ray production via neutron interactions on oxygen is essential for the study of neutrino neutral-current quasielastic interactions in water Cherenkov detectors. A measurement of γ-ray production from such reactions was performed using a 77 MeV quasi-monoenergetic neutron beam. Several γ-ray peaks, which are expected to come from neutron- 16 O reactions, are observed and production cross sections are measured for nine γ-ray components of energies between 2 and 8~MeV. Finally, these are the first measurements at this neutron energy using a nearly monoenergetic beam.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

Observations of modal coupling due to bolted joints in an experimental benchmark structure

The goal of this paper is to present a set of measurements from a benchmark structure containing two bolted joints to support future efforts to predict the damping due to the joints and to model nonlinear coupling between the first two elastic modes. Bolted joints introduce nonlinearities in structures, typically causing a softening in the natural frequency and an increase in damping because of frictional slip between the contact interfaces within the joint. These nonlinearities pose significant challenges when characterizing the response of the structure under a large range of load amplitudes, especially when the modal responses become coupled, causing the effective damping and natural frequency to not only depend on the excitation amplitude of the targeted mode, but also the relative amplitudes of other modes. In this work, two nominally identical benchmark structures, known in some prior works as the S4 beam, are tested to characterize their nonlinear properties for the first two elastic modes. Detailed surface measurements are presented and validated through finite element analysis and reveal distinct contact interactions between the two sets of beams. The free-free test structures are excited with an impact hammer and the transient response is analyzed to extract the damping and frequency backbone curves. A range of impact amplitudes and drive points are used to isolate a single mode or to excite both modes simultaneously. Differences in the nonlinear response correlate with the relative strength of the modes that are excited, allowing one to characterize mode coupling. Each of the beams shows different nonlinear properties for each mode, which is attributed to the different contact pressure distributions between the parts, although the mode coupling relationship is found to be consistent between the two. Lastly, the test data key finding are presented in this paper and the supporting data is available on a public repository for interested researchers.

42 ENGINEERING↗
DOE OSTI2020

Dissertation Proposal: Innovations in Pulsed Power and Plasma Science Theory Simulation and Experiment

Pulsed power and plasma physics are topics of great study at both Sandia National Laboratories (SNL or Sandia) and the University of New Mexico (UNM). The goal of this research is to further knowledge and understanding of these fields using the resources of both SNL and UNM in three ways. The first way is through the comprehension, application, and testing of theory. Reading and analytically deriving theoretical solutions of problems both real-world and simplified will allow for a fresh perspective and the furthering of the theory. One such theory is Ottinger's generalized theory for voltage measurement in magnetically insulated transmission lines (MITLs). By working through the math, a deeper understanding of the theory is gained from which one may add more physically accurate and/or more detailed physics into the theory. Additionally, understanding the theory lays a good foundation from which one can analyze, test, and compare results to the theory in the following two ways that will advance the fields of pulsed power and plasma physics. The second way is through the modeling and simulation of real-world and simplified problems that utilize and test the afore mentioned theories. Theory can be applied to a simulation domain by using the unstructured time-domain electromagnetic (UTDEM) codes EMPHASIS and EMPIRE as well as the physical modeling software CUBIT, all of which were developed at SNL. Problems such as the modeling and design of the extended MITL on HERMES III, the understanding of space-charge-limited emission from vacuum cathodes, and the interaction between a relativistic electron beam and an ideal gas can all be modeled, simulated, and analyzed with this set of codes. Here the advantage is three-fold. Firstly, theory that describes our understanding of these problems can be put to the test and advanced through iterative simulation and analysis. Secondly, the understanding of these problems will have a positive impact on national security through the advancement of the technological capability of the United States of America. Thirdly, and not unrelated to the prior advantage, is the validation and verification of EMPIRE and EMPHASIS. This segues into the third way, which is through experiment and the comparison of experiment to simulated and theoretical results. Performing experimental comparisons completes the scientific method and grounds all of the work in reality. Being able to physically test theory and simulation is necessary for any real conclusions to be drawn. Another advantage for carrying out experimental work is to advance the physical testing capabilities of SNL. Several systems will be developed and tested through the course of this work that positively impact technological advancement of Sandia National Labs. Lastly, all of the above work will converge to yield a well-rounded perspective that ties the three categories of research together.

42 ENGINEERING↗
DOE OSTI2021

Experiment Simulation Configurations Approximating DUNE TDR

The Deep Underground Neutrino Experiment (DUNE) is a next-generation long-baseline neutrino oscillation experiment consisting of a high-power, broadband neutrino beam, a highly capable near detector located on site at Fermilab, in Batavia, Illinois, and a massive liquid argon time projection chamber (LArTPC) far detector located at the 4850L of Sanford Underground Research Facility in Lead, South Dakota. The long-baseline physics sensitivity calculations presented in the DUNE Physics TDR, and in a related physics paper, rely upon simulation of the neutrino beam line, simulation of neutrino interactions in the near and far detectors, fully automated event reconstruction and neutrino classification, and detailed implementation of systematic uncertainties. The purpose of this posting is to provide a simplified summary of the simulations that went into this analysis to the community, in order to facilitate phenomenological studies of long-baseline oscillation at DUNE. Simulated neutrino flux files and a GLoBES configuration describing the far detector reconstruction and selection performance are included as ancillary files to this posting. A simple analysis using these configurations in GLoBES produces sensitivity that is similar, but not identical, to the official DUNE sensitivity. DUNE welcomes those interested in performing phenomenological work as members of the collaboration, but also recognizes the benefit of making these configurations readily available to the wider community.

Abi, B↗
DOE OSTI2025

A search for Heavy Neutral Leptons with masses up to 150 MeV and studies on scintillation light detection in SBND

Introduction Neutrino physics is one of today’s most promising fields in particle physics. The discovery of neutrino oscillations is an evidence of their mass not being null. However, the Standard Model of elementary particles (SM) does not contain a mechanism that generates them, so we have to search beyond the SM to find answers. Other unknowns remain open, such as the amount of CP symmetry violated in the lepton sector that could help explain the differences between matter and antimatter that formed the present universe. Nor is it understood why these particles are so light, more than six orders of magnitude below the next fermion, the electron. A possible explana&#x2;tion is the existence of heavier neutrino mass states usually referred as heavy neutral leptons (HNLs). One of the most advanced technologies for detecting neutrino interactions is the liquid argon time projection chamber (LArTPC). LArTPC detectors form a 3D image of the ionized electrons in the interaction, producing a detailed description of each neutrino event. Argon is also a prolific scintillator (40k photons/MeV) with light signals indicat&#x2;ing the interaction time. The Short-Baseline Near Detector (SBND), a 112-active mass LArTPC at Fermilab, will measure millions of neutrino interactions from the Booster Neutrino Beam (BNB). As the near (L=110 m) detector of the Short-Baseline neutrino program, SBND will search for a fourth light neutrino (∼ eV) in the coming years. This hypothesis could explain the anomalous data observed in the LSND and MiniBooNE experiments.

Álvarez Garrote, Rodrigo [Madrid U.] (ORCID:000000↗
DOE OSTI2020

Understanding Critical Systematics on Neutrino Oscillation Experiments from Neutrino-Nucleus Interactions. Final report

This is a final report on the DOE grant DE-SC0017946: Understanding Critical Systematics on Neutrino Oscillation Experiments from Neutrino-Nucleus Interactions. The goal of this proposal was to better understand the complex many-body dynamics of neutrino-nucleus interactions in order to control the systematic uncertainties that will dominate current and future long-baseline neutrino experiments. This work was focused on a new and experimentally challenging aspect of the problem: measuring the abundance and kinematics of final state nucleons. The research leveraged two different detectors and beam energies: the Near Detector (ND) of the NOvA Experiment, off-axis on the NuMI beam- line, and the Accelerator Neutrino Neutron Interaction Experiment (ANNIE), on the Booster Neutrino Beam (BNB). The techniques developed will also help reject the dominant neutrino-induced backgrounds limiting future proton decay searches.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗