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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Stable Photoemission from the Wehnelt Aperture Surface in 4D Ultrafast Electron Microscopy

Here we show that photoemission with high long-term stability that is immediate and robust can be generated from the surface of the Wehnelt aperture in a TEG-based UEM. Further, we show that the resulting photobeam quality can be at least as good as that from LaB 6 , whether under photo or thermionic operation. We hypothesize that the energy distribution and the temporal properties of the beam are improved relative to LaB 6 owing to the closer match of photon energy to aperture work function.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Development and Test of a Large-aperture Nb3Sn Cos-theta Dipole Coil with Stress Management

The design concept of the Electron Ion Collider (EIC), which is under construction at BNL, considers adding a 2nd Interaction Region (IR) and detector to the machine after completion of the present EIC project. Recent progress with development and fabrication of large-aperture high-field magnets based on the Nb3Sn technology for the HL-LHC makes this technology interesting for the 2nd EIC IR. This paper summarizes the results of feasibility studies of large-aperture high-field Nb3Sn dipoles and quadrupoles for the 2nd EIC IR.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Quench Performance of a Large-Aperture Nb 3 Sn Cos-Theta Coil With Stress Management in Dipole Mirror Configurations

A 123-mm-aperture Nb 3 Sn cos-theta (CT) dipole coil with stress management (SM) has been developed at Fermilab to demonstrate and test the SM concept, including coil design, fabrication technology, and performance. The first SMCT1 coil has been fabricated and assembled together with a 60-mm-aperture Nb 3 Sn coil inside a dipole mirror structure and tested separately and in series with the inner coil. This article summarizes the design, parameters, and quench performance of the SMCT1 coil in a dipole mirror configuration.

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Design of B2PF: A Large Aperture Nb-Ti Dipole Magnet for the Electron-Ion Collider

Here, we present the initial design of the matching dipole B2PF, a large aperture cosine-theta magnet for the Electron-Ion Collider (EIC). First we share an optimized 2D magnet cross-section based on a double-layer design with Nb-Ti Rutherford cable. This cross-section is optimized to meet the required field quality in the 120 mm coil aperture both at the nominal operating current and considering iron saturation effects during the ramp. Next, we share a first design of the 3D coil ends optimized for windability, field quality, and minimizing the conductor peak field. Based on the resulting peak field, we evaluate the short-sample margin of the design for an operating target of 6.3 T dipole field at 1.9 K. Finally, we share an initial mechanical design study which utilizes a key-and-bladder support structure capable of adjusting magnet preload.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Design and Construction of a Prototype B1pF Large Aperture Rutherford Cable Superconducting Magnet for the EIC Interaction Region

Brookhaven National Laboratory (BNL) was chosen to host the international Electron-Ion Collider (EIC), which will collide high energy and highly polarized hadron and electron beams with a center of mass energy up to 140 GeV. The Interaction Region (IR) requires several large aperture, relatively high field superconducting dipole and quadrupole magnets, some of which are very closely spaced. B1pF is a large aperture (300 mm coil ID), medium field (4.2 T), 3 meter long superconducting dipole magnet. Its size is larger than the largest superconducting magnet in the RHIC accelerator (180 mm DX dipole, 4.2 T, 3.7 m long). As such, B1pF was chosen as the representative magnet to be prototyped to demonstrate the technological choice, design and construction details. Here, this paper describes the analyses and considerations which informed both the magnet and magnet tooling designs. This paper will summarize the construction results so far, in particular the plan for novel coil winding tooling and the test coil winding & curing program that was carried out prior to coil and magnet construction.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2026

Double Aperture HTS Dipole Magnet Model for the Persistent Current Operation

Particle accelerators use many different types of magnets. There is an interest in replacing rather low-field conventional resistive magnets with high-temperature superconducting (HTS) magnets. The main goal is to reduce operational expenses, which is critical during the continuously increasing cost of electricity. At Fermilab, several HTS accelerator magnets were built and successfully tested. The paper described a variant of the double-aperture dipole magnet that could be suitable for future Lepton Colliders. A single short-circuited HTS coil of 3.8 kA generates a homogeneous magnetic field of 57 mT in both magnet gaps of 84 mm. The short model magnet was designed, built, and successfully tested at liquid nitrogen temperature. This magnet works in a persistent current mode, which provides additional cost savings when used in particle storage rings operated at a stable magnetic field. The results of design, fabrication, and tests are presented and discussed. The magnet demonstrated a high magnetic field stability in both apertures, efficiency of correction coils, and primary powering circuit.

Kashikhin, Vladimir [Fermilab] (ORCID:000000017249↗
DOE OSTI2025

Characterization of a multi-kW, large-aperture gas-cooled Faraday rotator

We characterize a large-aperture gas-cooled Faraday rotator (FR) designed to mitigate stress-induced depolarization in high-energy, high-power laser systems. The rotator, based on ceramic TGG, was tested using a 150 mW probe beam at 1047 nm and a pump beam at 1070 nm. Compensating for the birefringence induced by the surrogate depolarization plate at 3.3 kW of effective pump power, the rotator reduces the spatially in-homogeneous depolarized light containing linear, circular, and elliptical polarization states to nearly linear with approximately 0.8% (or −21 dB) of residual depolarized energy. The FR demonstrated effective depolarization compensation across its 58×58 mm 2 aperture.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

Dynamic Aperture Evaluation for the Hadron Storage Ring in the Electron-Ion Collider

The Electron-Ion Collider (EIC) is aiming at a design luminosity of 1e34 cm⁻²s⁻¹. To maintain such a high luminosity, both beams in the EIC need an acceptable beam lifetime in the presence of the beam-beam interaction. For this purpose, we carried out weak-strong element-by-element particle tracking to evaluate the long-term dynamic aperture for the hadron ring lattice design. We improved our simulation code SimTrack to treat some new lattice design features, such as radially offset on-momentum orbits, coordinate transformations in the interaction region, etc. In this article, we will present the preliminary dynamic aperture calculation results with β^{*}- function scan, radial orbit shift, crossing angle collision, and magnetic field errors.

Luo, Y.↗
DOE OSTI2020

Bistatic Synthetic Aperture Radar - Issues Analysis and Design

The physical separation of the transmitter from the receiver into perhaps separate flight vehicles (with separate flight paths) in a bistatic Synthetic Aperture radar system adds considerable complexity to an already complex system. Synchronization of waveform parameters and timing attributes become problematic, and notions of even the synthetic aperture itself take on a new level of abstractness. Consequently, a high-performance, fine-resolution, and reliable bistatic SAR system really needs to be engineered from the ground up, with tighter specifications on a number of parameters, and entirely new functionality in other areas. Nevertheless, such a bistatic SAR system appears viable.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

Using Forward-Reversal Integration to Optimize EIC's e-ring Dynamic Aperture

The forward-reversal integration has been proved efficient in optimizing the dynamic aperture for light source rings, which usually have a multi-fold periodical lattice structure. This method has been integrated into the ELEGANT code since the version 2019.4. In this technote, this approach has been used to optimize the dynamic aperture of a collider ring, i.e., the future electron ion collider’s (EIC) e-ring.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Synthetic Aperture Radar Height of Focus

Synthetic Aperture Radar (SAR) projects a 3-D scene’s reflectivity into a 2-D image. In doing so, it generally focusses the image to a surface, usually a ground plane. Consequently, scatterers above or below the focal/ground plane typically exhibit some degree of distortion manifesting as a geometric distortion and misfocusing or smearing. Limits to acceptable misfocusing define a Height of Focus (HOF), analogous to Depth of Field in optical systems. This may be exacerbated by the radar’s flightpath during the synthetic aperture data collection. It might also be exploited for target height estimation and offer insight to other height estimation techniques.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Source Physics Experiment: Rock Valley Interferometric Synthetic Aperture RADAR Earthquake Detection Study

Seismic signals from 1993 show a series of magnitude (Mw) 3.7 or less seismic events in Rock Valley on the Nevada National Security Site (NNSS). Historic synthetic aperture radar images of that location were found that could provide interferometric synthetic aperture radar (InSAR) measures of the ground height during 1993. Given this historic SAR imagery, we explore answering the question if ground movement from the 1993 Rock Valley earthquake activity could be sensed by remote sensing means. Finding earthquake surface movement would assist in locating the Rock Valley fault and the 1993 earthquake hypocenter where the Source Physics Experiment Phase III series of experiments will be conducted. In this report, we show that InSAR can sense very small height differences, and for the European Radar Satellite-1 InSAR collections during 1992 and 1993 over Rock Valley earth surface movements were measured with 8 mm uplift and 12.5 mm subsidence over isolated areas. One of these earth movement areas coincides with an InSAR image pair coherence drop between March 5, 1993 and June 18, 1993. The coherence drop is over an approximately 13 square km area south southeast of Skull Mountain centered at 36° 43' 30" N latitude and 116° 05' 00" W longitude. Measured small surface movement and a loss of InSAR coherence may be caused by the series of earthquakes. The location of these InSAR detections may also coincide with water drainage or erosion displacement. There are no records to disambiguate the earthquake and erosion earth surface motion possibilities. Therefore, the InSAR findings of earth surface movement by InSAR are inconclusive.

58 GEOSCIENCES↗
DOE OSTI2022

Extension of Interferometric Synthetic Aperture Radar to Multiple Phase-Centers (Midyear LDRD Final Report – second edition)

This document contains the final report for the midyear LDRD titled "Extension of Interferometric Synthetic Aperture Radar to Multiple Phase-Centers." This report presents an overview of several methods for approaching the two-target in layover problem that exists in interferometric synthetic aperture radar systems. Simulation results for one of the methods are presented. In addition, a new direct approach is introduced.

42 ENGINEERING↗
DOE OSTI2023

Dynamic Aperture of the PIP-II Accumulator Ring (PAR)

The Proton Improvement Plan-II (PIP-II) will include a superconducting linear accelerator which will accelerate H- ions to 800MeV, at an intensity never seen before. A proposed PIP-II Accumulator Ring (PAR) can reduce the injection losses to the booster, enhance the ramp up of the Long Baseline Neutrino Facility (LBNF) and support experiments in Dark Sector Physics. When the beam is circulating in PAR at its full intensity, it will then be transferred to the Booster via single turn injection. Strong PAR focusing results in larger phase advances, shorter focal lengths and higher machine tunes, which creates robust beam envelope control. Particles will be able to survive modest excursions from the elliptical phase-space trajectories of linear optics, and any loss of particles would be due to reduced dynamic aperture. The values for tunes and chromaticities are flexible and will continue to evolve as the lattice matures. Since there will be non-linear terms impacting the particles’ trajectories, tracking will include realistic magnetic field errors and installation alignment errors to determine the dynamic aperture as a function of the machine tunes. This will allow us to determine the optimum operating point in phase-space.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

The Simons Observatory: Design, Integration, and Testing of the Small Aperture Telescopes

The Simons Observatory (SO) is a cosmic microwave background survey experiment that includes small-aperture telescopes (SATs) observing from an altitude of 5200 m in the Atacama Desert in Chile. The SO SATs will cover six spectral bands between 27 and 280 GHz to search for primordial B-modes to a sensitivity of σ(r) = 0.002, with quantified systematic errors well below this value. Each SAT is a self-contained cryogenic telescope with a 35° field of view, 42 cm diameter optical aperture, 40 K half-wave plate, 1 K refractive optics, and <0.1 K focal plane that holds >12,000 transition edge sensor detectors. We describe the nominal design of the SATs and present details about the integration and testing for one operating at 93 and 145 GHz.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1972

Reduction of near-in sidelobes using phase reversal aperture rings

A technique is described for reducing near-in sidelobes in spacecraft antennas by cancellation. This technique takes a small portion of the radiation from the antenna aperture and generates the near-in lobes, which are then fed out of phase relative to the main signal. Results of sample cases indicate that the first three lobes can be nearly eliminated at a 40% reduction in aperture efficiency.

Williams, W. F.↗
NASA NTRS1972

Computations of the aperture admittance of an axial slot on a dielectric coated cylinder.

An extensive set of curves for the aperture admittance of a waveguide-fed axial slot on a coated metal cylinder is presented for both an underdense plasma and a Teflon coating. Examination of these curves shows that a slot on a cylinder with a Ka of 2 to 3 has about the same aperture admittance as the identical slot opening onto a flat ground plane.

Croswell, W. F.↗