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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Transportation of high-current ion and electron beams in the accelerator drift gap in the presence of an additional electron background

The dynamics of a high-current ion beam propagating in the drift gap of a linear induction accelerator with collective focusing is studied using 3D numerical simulations in the framework of the full system of the Vlasov–Maxwell equations (code KARAT). The ion beam is neutralized by a comoving electron beam in the current density and, partially, in space charge, since the velocities of electrons and ions differ substantially. The dynamics of the high-current ion beam is investigated for different versions of additional neutralization of its space charge. It is established that, for a given configuration of the magnetic field and in the presence of a specially programmed injection of additional electrons from the boundary opposite to the ion injection boundary, the angular divergence of the ion beam almost vanishes, whereas the current of the ion beam at the exit from the accelerator drift gap changes insignificantly and the beam remains almost monoenergetic.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS2024

Radial Variations in Solar Type III Radio Bursts

Type III radio bursts are generated by electron beams accelerated at reconnection sites in the corona. This study, utilizing data from the Parker Solar Probe's first 17 encounters, closely examines these bursts down to 13 solar radii. A focal point of our analysis is the near-radial alignment (within 5°) of the Parker Solar Probe, STEREO-A, and Wind spacecraft relative to the Sun. This alignment, facilitating simultaneous observations of 52 and 27 bursts by STEREO-A and Wind respectively, allows for a detailed differentiation of radial and longitudinal burst variations. Our observations reveal no significant radial variations in electron beam speeds, radio fluxes, or exponential decay times for events below 50 solar radii. In contrast, closer to the Sun we noted a decrease in beam speeds and radio fluxes. This suggests potential effects of radio beaming or alterations in radio source sizes in this region. Importantly, our results underscore the necessity of considering spacecraft distance in multispacecraft observations for accurate radio burst analysis. A critical threshold of 50 solar radii emerges, beyond which beaming effects and changes in beam speeds and radio fluxes become significant. Furthermore, the consistent decay times across varying radial distances point toward a stable trend extending from 13 solar radii into the inner heliosphere. Our statistical results provide valuable insights into the propagation mechanisms of type III radio bursts, particularly highlighting the role of scattering near the radio source when the frequency aligns with the local electron plasma frequency.

Vratislav Krupar↗
DOE OSTI2017

Resonance Control System for the CEBAF Separator Upgrade

Abstract The Continuous Electron Beam Accelerator Facility (CEBAF) energy upgrade from 6 GeV to 12 GeV includes the installation of four new 748.5 MHz normal conducting deflecting cavities in the 5th pass extraction region. The RF system employs two digital LLRF systems controlling four normal conducting cavities in a vector sum setting. Cavity tune information of the individual cavities is obtained using a multiplexing scheme of the forward and reflected RF signals. Water skids equipped with heaters and valves are used to control resonance. A new FPGA-based hardware and EPICS-based predictive control algorithm has been developed to support reliable operation of the beam extraction process. This paper presents the architecture design of the existing hardware and software as well as a plan to develop a model predictive control system.

Plawski, Tomasz↗
DOE OSTI2020

Advanced Laser-driven Plasma Accelerator Electron-beam Diagnostics with COTR Techniques

A significant advance in laser-driven plasma accelerator (LPA) electron-beam diagnostics has recently been demonstrated based on coherent optical transition radiation (COTR) imaging. We find COTR signal strengths from a microbunched subset of beam exiting the LPA to be several orders of magnitude higher than that of incoherent optical transition radiation (OTR). The transverse sizes are only a few microns as deduced from the point-spread-function-related lobe structure. In addition, the far-field COTR interferometric images obtained on the same shot provide beam-size limits plus divergence and pointing information at the sub-mrad level when compared to a modified analytical model. The integrated image intensities can be used to estimate the microbunching fraction and relatable to the LPA process. Initial results in a collaborative LPA experiment will be reported for electron beam energies of about 215 MeV. A revised configuration is proposed to record energy and ene rgy spread via COTR on the same shot with the interferometer.

43 PARTICLE ACCELERATORS↗
DOE OSTI2026

High Energy Neutrino Physics

Of the twelve subatomic particles that are the building blocks of all the known matter in the universe, three are neutrinos, small neutral particles that interact through the weak interaction with other particles in the Universe. These three neutrinos, paired with the three charged leptons, the familiar electron, the heavier muon, and the still heavier tau, are some of the least well understood particles of these building blocks. Experiments using accelerator beams, like those that are the subject of this grant, can address some of the key questions scientists are posing with respect to the neutrino. Specifically, are there differences between neutrinos and their anti-particles, anti-neutrinos, that could give us some clue to the matter dominated universe, do we understand the spectrum of masses of the three neutrinos, and are there other kinds of neutirnos than the three neutrinos? Coupled with advances in precision neutrino detection, the US is addressing these questions from small scale experiments to the massive DUNE experiment. PI Fleming and her team play critical roles in accelerator based neutrino physics at short and long baseline with participation on MicroBooNE, SBND, and with the group's participation in DUNE. These experiments are at the heart of the US-based high energy physics program.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

Design study of a 17.3 GHz electron cyclotron resonance (ECR) ion source at Louvain-la-Neuve

The Cyclotron Resources Center of the Louvain-la-Neuve University is developing a new electron cyclotron resonance ion source to increase the energy of the accelerated beam by injection of higher charge state ions into the cyclotron. The design of the source is based on a 17.3 GHz frequency and classical coils to produce the axial field. The field reaches 2 T at the injection side and 1.2 T at extraction. The total power consumption for the coils is limited to 80 kW. The design features of the source are presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Future Plans of Telescope Array

The Telescope Array (TA) experiment is the only ultra high energy cosmic ray observatory in the northern hemisphere. In addition, it will be the world's first air shower detector to be directly calibrated by an on-site accelerator beam. For wider and deeper understanding of cosmic rays by via high precision measurements, we have undertaken the study of extension plans for TA. One extension plan will extend the sensitive energy range of TA down to 10{sup 17} eV. A second plan would extend of the aperture area of the SD array. These plans are described in this note.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Impact of Solenoid Induced Residual Magnetic Fields on The Prototype SSR1 CM Performance

A prototype cryomodule containing eight Single Spoke Resonators type-1 (SSR1) operating at 325 MHz and four superconducting focusing lenses was successfully assembled, cold tested, and accelerated beam in the framework of the PIP-II project at Fermilab. The impact of induced residual magnetic fields from the solenoids on performance of cavities is presented in this contribution. In addition, design optimizations for the production cryomodules as a result of this impact are highlighted.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

The Meson Spectroscopy Program Using the Forward Tagger with CLAS12 at Jefferson Lab

The 12 GeV upgrade to the Continuous Electron Beam Accelerator Facility (CEBAF) will enable a new generation of experiments in hadronic nuclear physics at Jefferson Lab, seeking to address fundamental questions in QCD. For example, confirming the existence of exotic states, suggested by both quark models and lattice calculations, would allow gluonic degrees of freedom to be explored, and may help explain the role played by gluons in the QCD interaction. In Experimental Hall B, meson spectroscopy (the MesonEx experiment) will be performed using low Q2 electron scattering to produce quasi-real photons. The scattered electron is detected at small angles by the Forward Tagger device, determining the properties of the photon on an event-by-event basis. This technique has notable advantages over real photon beams, and over hadronic beam experiments, where most experimental data exists. This article will focus on the development of the Forward Tagger by the INFN Genova group, and the proposed MesonEx experiment.

Fegan, Stuart↗
DOE OSTI2015

Tests of innovative photon detectors and integrated electronics for the large-area CLAS12 ring-imaging Cherenkov detector

A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Lab. Its aim is to study the 3D nucleon structure in the yet poorly explored valence region by deep-inelastic scattering, and to perform precision measurements in hadron spectroscopy. The adopted solution foresees a novel hybrid optics design based on an aerogel radiator, composite mirrors and a densely packed and highly segmented photon detector. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). Extensive tests have been performed on Hamamatsu H8500 and novel flat multi-anode photomultipliers under development and on various types of silicon photomultipliers. A large scale prototype based on 28 H8500 MA-PMTs has been realized and tested with few GeV/c hadron beams at the T9 test-beam facility of CERN. In addition a small prototype was used to study the response of customized SiPM matrices within a temperature interval ranging from 25 down to –25 °C. The preliminary results of the individual photon detector tests and of the prototype performance at the test-beams are here reported.

Cherenkov radiation↗
DOE OSTI2011

Temperature dependence of yields from multi-foil SPES target

The temperature dependence of neutron-rich isotope yields was studied within the framework of the HRIBF-SPES Radioactive Ion Beams (RIB) project. On-line release measurements of fission fragments from a uranium carbide target at 1600 C, 1800 C and 2000 C were performed at ORNL (USA). The fission reactions were induced by a 40 MeV proton beam accelerated into a uranium carbide target coupled to a plasma ion source. The experiments allowed for tests of performance of the SPES multi-foil target prototype loaded with seven UC{sub 2}/graphite discs (ratio C/U = 4) with density about 4 g/cm{sup 3}.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2023

Initial Conditioning of the Rod-style RFQ

The RFQ test stand will allow new sources to be tested and will provide information on the performance of our RFQ designs. The RFQ must sustain the high peak power that will be necessary for bunching and accelerating beam, and that peak power must be sustained at a duty factor that is higher than other facilities that use similar rod-style RFQs. The conditioning of the RFQ allows both requirements to be tested, and in addition the intricacies of its operation are discovered and can be corrected for future work. In addition, the conditioning procedure was able to be done concurrently with the source development.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Deep Learning Based Superconducting Radio-Frequency Cavity Fault Classification at Jefferson Laboratory

This work investigates the efficacy of deep learning (DL) for classifying C100 superconducting radio-frequency (SRF) cavity faults in the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. CEBAF is a large, high-power continuous wave recirculating linac that utilizes 418 SRF cavities to accelerate electrons up to 12 GeV. Recent upgrades to CEBAF include installation of 11 new cryomodules (88 cavities) equipped with a low-level RF system that records RF time-series data from each cavity at the onset of an RF failure. Typically, subject matter experts (SME) analyze this data to determine the fault type and identify the cavity of origin. This information is subsequently utilized to identify failure trends and to implement corrective measures on the offending cavity. Manual inspection of large-scale, time-series data, generated by frequent system failures is tedious and time consuming, and thereby motivates the use of machine learning (ML) to automate the task. This study extends work on a previously developed system based on traditional ML methods (Tennant and Carpenter and Powers and Shabalina Solopova and Vidyaratne and Iftekharuddin, Phys. Rev. Accel. Beams, 2020, 23, 114601), and investigates the effectiveness of deep learning approaches. The transition to a DL model is driven by the goal of developing a system with sufficiently fast inference that it could be used to predict a fault event and take actionable information before the onset (on the order of a few hundred milliseconds). Because features are learned, rather than explicitly computed, DL offers a potential advantage over traditional ML. Specifically, two seminal DL architecture types are explored: deep recurrent neural networks (RNN) and deep convolutional neural networks (CNN). We provide a detailed analysis on the performance of individual models using an RF waveform dataset built from past operational runs of CEBAF. In particular, the performance of RNN models incorporating long short-term memory (LSTM) are analyzed along with the CNN performance. Furthermore, comparing these DL models with a state-of-the-art fault ML model shows that DL architectures obtain similar performance for cavity identification, do not perform quite as well for fault classification, but provide an advantage in inference speed.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2014

Study of {sup 24}Mg resonances relevant for carbon burning nucleosynthesis

We have studied decays of resonances in {sup 24}Mg at excitation energies above the {sup 12}C+{sup 12}C decay threshold, using {sup 12}C({sup 16}O,α){sup 24}Mg* reaction. This experiment has been performed at INFNLNS, using Tandem accelerator beam of 16O at E = 94 MeV. Some preliminary results are presented.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2013

Increasing energy coupling into plasma waves by tailoring the laser radial focal spot distribution in a laser wakefield accelerator

By controlling the focal spot quality with a deformable mirror, we are able to show that increasing the fraction of pulse energy contained within the central part of the focal spot, while keeping the total energy and central spot size constant, significantly increases the amount of energy transferred to the wakefield: Our measurements show that the laser loses significantly more laser energy and undergoes greater redshifting and that more charge is produced in the accelerated beam. Three dimensional particle in cell simulations performed with accurate representations of the measured focal spot intensity distribution confirm that energy in the wings of the focal spot is effectively wasted. Even though self-focusing occurs, energy in the wings of the focal spot distribution is not coupled into the wakefield, emphasising the vital importance of high quality focal spot profiles in experiments.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

High Energy Systems for Transforming CO 2 to Valuable Products (Final Report)

The objective of this project is to develop the Direct E-Beam Synthesis (DEBS) process that uses high-energy electron beams (E-Beam) to break chemical bonds. This allows the production of valuable chemicals, such as acetic acid, methanol, and carbon monoxide, at relatively low severity (pressure near one atmosphere and temperatures <150°C) from near-pure CO 2 captured from a pulverized coal-fired power plant and methane, imported as natural gas. Creating such valuable products will offset the cost of carbon capture and storage. Through this project, we have designed, constructed, and operated an E-Beam reactor to examine the feasibility of performing dry reforming reaction without a catalyst using only DEBS. We have verified the production of syngas with 1:1 H2:CO ratio and calculated that the energy cost for conversion is about 5.2 eV/molecule of product for dry reforming reaction which is similar to the energy cost for conversion using conventional thermochemical conversion but under significantly milder conditions (room temperature and atmospheric pressure). We have performed a technoeconomic analysis (TEA) to estimate the total capital requirement and the cost of production for a 99.4 MMSCFD syngas production plant via non-catalytic Direct E-Beam Synthesis (DEBS) technology utilizing a high-energy electron beam (E-Beam) accelerator. No assumption is made for syngas utilization downstream, and the incoming reactants are pure CO 2 from carbon capture (assumed to be at zero cost) and natural gas. The Total As-Spent Cost (TASC) was calculated to be $\$242.5$ million, resulting in a levelized cost of syngas (LCOS) of $\$175.84$/tonne (metric) at a natural gas price of $\$6.24$/MMBTU1. The cost of syngas is primarily determined by the price of natural gas. If the cost of the CO 2 feedstock is assumed to be non-zero, then the price of the CO 2 feed also heavily influences the levelized cost of syngas. The potential impact on the cost of electricity from syngas revenue is significant. Following DOE NETL’s guidance, a lifecycle analysis (LCA) was conducted to compare the cradle-to-gate life cycle emissions of GTI Energy’s novel Direct E-Beam Synthesis (DEBS) process that produces syngas via the reaction of methane and carbon dioxide to the emissions of a state-of-the-art Steam Methane Reforming (SMR) process that also produces syngas via the reaction of methane and steam. The DEBS process results in less GHG emissions than SMR (with CO product as the basis of comparison). openLCA was used for the LCA and the results show that the total global warming potential (GWP) of DEBS is 0.981 kg CO 2 e per kg CO product, while the SMR process has a global warming potential of 2.573 kg CO 2 e per kg CO product. The ratio of the GWP of the proposed product system to the comparison product system is 0.381. This percent change is 61.9% lower GWP than SMR.

20 FOSSIL-FUELED POWER PLANTS↗