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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 1,441 records · Page 80
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Double lens device for tunable harmonic generation of laser beams in KBBF/RBBF crystals or other non-linear optic materials

A method and apparatus to generate harmonically related laser wavelengths includes a pair of lenses at opposing faces of a non-linear optical material. The lenses are configured to promote incoming and outgoing beams to be normal to each outer lens surface over a range of acceptance angles of the incoming laser beam. This reduces reflection loss for higher efficiency operation. Additionally, the lenses allow a wider range of wavelengths for lasers for more universal application. Examples of the lenses include plano-cylindrical and plano-spherical form factors.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Second harmonic generation in resonant optical structures

An optical second-harmonic generator (or spontaneous parametric down-converter) includes a microresonator formed of a nonlinear optical medium. The microresonator supports at least two modes that can be phase matched at different frequencies so that light can be converted between them: A first resonant mode having substantially radial polarization and a second resonant mode having substantially vertical polarization. The first and second modes have the same radial order. The thickness of the nonlinear medium is less than one-half the pump wavelength within the medium.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Garnet Ring Measurements for the Fermilab Booster 2nd Harmonic Cavity

A perpendicularly biased tuneable 2nd harmonic cavity is being constructed for use in the Fermilab Booster. The cavity's tuner uses National Magnetics AL800 garnet as the tuning media. For quality control, the magnetic properties of the material and the uniformity of the properties within the tuner must be assessed. We describe two tests which are performed on the rings and on their corresponding witness samples.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Progress on the Construction of the Perpendicularly Biased 2nd Harmonic Cavity for the Fermilab Booster

A perpendicularly biased tuneable 2nd harmonic cavity, designed for the Fermilab Booster, is being assembled for testing this summer (2018). The cavity will work at twice the frequency of the fundamental cavities, and will be on only during the injection and transition (or extraction) periods. The main reason for adding this cavity is to improve beam capture and reduce losses as required by Fermilab's Proton Improvement Plan (PIP). After three years optimization and study, the cavity design has now been finalized and all constituent parts have been received. We report on the cavity final design and on the status of the construction.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Garnet Ring Measurements for the Fermilab Booster 2nd Harmonic Cavity

A perpendicularly biased tuneable 2nd harmonic cavity is being constructed for use in the Fermilab Booster. The cavity's tuner uses National Magnetics AL800 garnet as the tuning media. For quality control, the magnetic properties of the material and the uniformity of the properties within the tuner must be assessed. We describe two tests which are performed on the rings and on their corresponding witness samples.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Progress on the Construction of the Perpendicularly Biased 2nd Harmonic Cavity for the Fermilab Booster

A perpendicularly biased tuneable 2nd harmonic cavity, designed for the Fermilab Booster, is being assembled for testing this summer (2018). The cavity will work at twice the frequency of the fundamental cavities, and will be on only during the injection and transition (or extraction) periods. The main reason for adding this cavity is to improve beam capture and reduce losses as required by Fermilab's Proton Improvement Plan (PIP). After three years optimization and study, the cavity design has now been finalized and all constituent parts have been received. We report on the cavity final design and on the status of the construction

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

The FNAL Booster 2nd Harmonic RF Cavity

A second harmonic RF cavity which uses perpendicularly biased garnet for frequency tuning is currently being constructed for use in the Fermilab Booster. The cavity will operate at twice the fundamental RF frequency, from ~76 - 106 MHz, and will be turned on only during injection, and transition or extraction. Its main purpose is to reduce beam loss as required by Fermilab’s Proton Improvement Plan (PIP). After three years of optimization and study, the cavity design has been finalized and all constituent parts have been received. We discuss the design aspects of the cavity and its associated systems, component testing, and status of the cavity construction.

43 PARTICLE ACCELERATORS↗
DOE OSTI2019

Harmonic adsorption recuperative power systems and methods

A new power generation thermodynamic cycle is described that eliminates need for bulk liquid condensation and vaporization steps required in conventional ORC power systems. An exemplary harmonic adsorption recuperative power cycle system offers more efficient power generation as compared with conventional ORC systems. A multibed adsorption system is used to provide thermal compression for the cycle. An adsorption compressor contains a sorbent with strong adsorption affinity for the working fluid in the pores while well outside the P-T conditions needed to condense the liquid phase, allowing the adsorption compressor to reduce operating pressure exiting the expander.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2019

Characterization of trace crystallinity by second harmonic generation microscopy

A method for quantifying crystallinity within a sample using second harmonic generation microscopy is described herein. In one aspect, a method for reducing the timeframe for accelerated stability testing of amorphous solid dispersions of active pharmaceutical ingredients though identifying regions of interest to quantify crystallinity and composition is presented herein.

Simpson, Garth Jason↗
DOE OSTI2019

NUREG/CR-7239, “Review of Fissile Material Exemptions and General Licenses in 10 CFR Part 71,” and Proposed Revisions to Harmonize with IAEA SSR-6 Fissile Material Requirements

Title 10 of the United States (US) Code of Federal Regulations (CFR), Part 71, Packaging and Transportation of Radioactive Material, includes requirements for the transport of fissile material in packages. These regulations provide requirements for packaging that is certified by the US Nuclear Regulatory Commission (NRC) to transport fissile material. The regulations also include provisions that allow for shipment in packages that are not required to be certified by the NRC. These provisions include criteria for exemptions from classification as fissile material (§71.15) and permit general licenses for limited quantities of fissile material and plutonium-beryllium special form sources (§71.22 and §71.23, respectively). This paper will discuss recommendations that NRC has made on the use of the fissile material exemptions and general license provisions in a recently published NUREG/CR, and changes to these provisions proposed for an upcoming rulemaking action.NUREG/CR-7239, “Review of Fissile Material Exemptions and General Licenses in 10 CFR Part 71,” was recently developed by Oak Ridge National Laboratory (ORNL) for the NRC. This document provides technical recommendations to fissile material licensees on how to apply the fissile material exemption and general license regulations. This paper will outline this NUREG/CR, including: 1) the technical basis, intent, and anticipated usage of each of the fissile material exemption and general license provisions; 2) the recent regulatory history of the Part 71 fissile material exemptions and general licenses; and 3) example problems which illustrate how the provisions might be applied and justified.In 2012, IAEA made several significant changes to the fissile material requirements in SSR-6, including the fissile exception provisions and provisions similar to the U.S. fissile material general licenses. In 2016, the NRC began a rulemaking effort to consider these changes (among others), and to decide how to best harmonize the domestic U.S. regulations. This paper will review the 2012 changes made to SSR-6, discuss the NRC staff consideration of those changes, and detail the proposed revisions to 10 CFR Part 71 that NRC is considering for the fissile material exemptions and general licenses.

Barto, Andrew↗
DOE OSTI2020

Probing and manipulating magnetic and 2D quantum materials using ultrafast laser and high harmonic sources

The ability to probe the full dynamic response of quantum materials on the length- and time-scales (Å to attoseconds on up) fundamental to charge, spin and phonon interactions is leading to a host of new discoveries. The coupled interactions between charges, spins, orbital and lattice degrees of freedom are key to determining the state of a material, whether metallic, insulating, superconducting or magnetic. Under thermal equilibrium conditions these states can be tuned by varying the temperature, pressure, chemical doping or dimensionality. However, their inherent complexity and rich phase landscape make them challenging to understand or manipulate deterministically. Fortunately, ultrafast light sources have undergone remarkable advances in recent years, achieving what was merely a dream three decades ago, i.e., full coherent control of light fields spanning the THz to the X-ray regions. Here, these new capabilities are providing powerful new tools for coherently manipulating and probing quantum materials using light. Recent advances in high harmonic generation (HHG) have provided new techniques for uncovering new phases and couplings in 2D and magnetic materials, using femtosecond lasers to coherently manipulate and tune the properties and interactions in the material, and HHG as a probe to map out these new phases and couplings. There are several beautiful recent observations of exciting new states in materials using light, but in some cases, the limited experimental data points made it challenging to validate an interpretation. The new ability of ultrafast HHG-based photoemission and magneto-optic spectroscopies to precisely probe multiple phases, electronic and magnetic order parameters, when combined with scanning the laser excitation fluence, is allowing us to map how material phases, magnetic states, and electron-phonon-spin couplings in these delicate materials.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

STUDY OF HARMONIC CRAB CAVITY IN EIC BEAM-BEAM SIMULATIONS

In the Electron-Ion Collider (EIC) design, crab cavities are adopted to compensate the geometric luminosity loss from the crossing angle. From previous studies, higher-order synchro-betatron resonances are excited since the hadron beam is long and the crossing angle is large. To reduce the luminosity degradation rate, different combinations of harmonic crab cavities are studied with both weak-strong and strong-strong simulation methods. The frequency map analysis (FMA) is also used for comparison. This study helps determine the crab cavity parameters for the future EIC.

43 PARTICLE ACCELERATORS↗
DOE OSTI2013

Surface harmonics method for two-dimensional time-dependent neutron transport problems of square-lattice nuclear reactors

Time-dependent equations of the Surface Harmonics Method (SHM) have been derived from the time-dependent neutron transport equation with explicit representation of delayed neutrons for solving the two-dimensional time-dependent problems. These equations have been realized in the SUHAM-TD code. The TWIGL benchmark problem has been used for verification of the SUHAM-TD code. The results of the study showed that computational costs required to achieve necessary accuracy of the solution can be an order of magnitude less than with the use of the conventional finite difference method (FDM). (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2018

Localized harmonic characteristic basis functions for multiscale finite element methods

We solve elliptic systems of equations posed on highly heterogeneous materials. Examples of this class of problems are composite structures and geological processes. We focus on a model problem which is a second-order elliptic equation with discontinuous coefficients. These coefficients represent the conductivity of a composite material. We assume a background with a low conductivity that contains inclusions with different thermal properties. Under this scenario, we design a multiscale finite element method to efficiently approximate solutions. The method is based on an asymptotic expansion of the solution in terms of the ratio between the conductivities. The resulting method constructs (locally) finite element basis functions (one for each inclusion). These bases generate the multiscale finite element space where the approximation of the solution is computed. Numerical experiments show the good performance of the proposed methodology.

97 MATHEMATICS AND COMPUTING↗