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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Note: Enhanced production of He{sup +} from the Versatile Ion Source (VIS) in off-resonance configuration

The Versatile Ion Source (VIS) is a microwave discharge ion source installed at INFN-LNS and here used as test-bench for the production of high intensity low emittance proton beams and for studies on plasma physics. A series of measurements have been carried out with VIS in order to test the source with light ions. In particular a He{sup +} beam has been characterized in terms of plasma discharge parameters. The experiment has been triggered by the observation of X-radiation emission from the plasma for some configuration of the magnetic field profile. The plasma electron energy distribution function is in fact modified when in some regions of the plasma chamber under-resonance discharge takes place, fulfilling the condition that allows the electromagnetic wave to electrostatic wave conversion. These tests allowed obtaining more than 50 mA of He{sup +} beams.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

Versatile cold atom source for multi-species experiments

We present a dual-species oven and Zeeman slower setup capable of producing slow, high-flux atomic beams for loading magneto-optical traps. Our compact and versatile system is based on electronic switching between different magnetic field profiles and is applicable to a wide range of multi-species experiments. We give details of the vacuum setup, coils, and simple electronic circuitry. In addition, we demonstrate the performance of our system by optimized, sequential loading of magneto-optical traps of lithium-6 and cesium-133.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

A versatile, pulsed anion source utilizing plasma-entrainment: Characterization and applications

A novel pulsed anion source has been developed, using plasma entrainment into a supersonic expansion. A pulsed discharge source perpendicular to the main gas expansion greatly reduces unwanted “heating” of the main expansion, a major setback in many pulsed anion sources in use today. The design principles and construction information are described and several examples demonstrate the range of applicability of this anion source. Large OH{sup −}(Ar){sub n} clusters can be generated, with over 40 Ar solvating OH{sup −}. The solvation energy of OH{sup −}(Ar){sub n}, where n = 1-3, 7, 12, and 18, is derived from photoelectron spectroscopy and shows that by n = 12-18, each Ar is bound by about 10 meV. In addition, cis– and trans– HOCO{sup −} are generated through rational anion synthesis (OH{sup −} + CO + M → HOCO{sup −} + M) and the photoelectron spectra compared with previous results. These results, along with several further proof-of-principle experiments on solvation and transient anion synthesis, demonstrate the ability of this source to efficiently produce cold anions. With modifications to two standard General Valve assemblies and very little maintenance, this anion source provides a versatile and straightforward addition to a wide array of experiments.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Development of versatile multiaperture negative ion sources

Enhancement of negative ion sources for production of large ion beams is a very active research field nowadays, driven from demand of plasma heating in nuclear fusion devices and accelerator applications. As a versatile test bench, the ion source NIO1 (Negative Ion Optimization 1) is being commissioned by Consorzio RFX and INFN. The nominal beam current of 135 mA at −60 kV is divided into 9 beamlets, with multiaperture extraction electrodes. The plasma is sustained by a 2 MHz radiofrequency power supply, with a standard matching box. A High Voltage Deck (HVD) placed inside the lead shielding surrounding NIO1 contains the radiofrequency generator, the gas control, electronics and power supplies for the ion source. An autonomous closed circuit water cooling system was installed for the whole system, with a branch towards the HVD, using carefully optimized helical tubing. Insulation transformer is installed in a nearby box. Tests of several magnetic configurations can be performed. Status of experiments, measured spectra and plasma luminosity are described. Upgrades of magnetic filter, beam calorimeter and extraction grid and related theoretical issues are reviewed.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Versatile common instrumentation for optical detection of pH and dissolved oxygen

The recent trend toward use of disposable and miniature bioreactors requires the use of appropriate sensors. pH and dissolved oxygen (DO) are often measured using optical chemical sensors due to their small form factor and convenience in use. These sensors are often interrogated using a specialized opto-electronic transducer that is designed around the optical sensor. In this contribution, we are presenting a new class of opto-electronic transducers that are usable with several different chemical sensors without the need to switch the optics or hardware when changing the type of the chemical sensor. This allows flexibility closer to the lab-grade devices while the size is closer to a dedicated sensor. This versatile instrumentation is capable of seamlessly switching between the pH and DO measurement modes and is capable of auto recognition of the sensor type. The principle of ratiometric fluorescence is used for pH measurements, and that of fluorescence lifetime for DO measurements. An approach to obtain identical calibrations between several devices is also presented. The described hardware constitutes common instrumentation for measuring either pH or DO and has been tested in actual bioprocesses. It has been found adequate for continuous bioprocess monitoring.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

Versatile alignment layer method for new types of liquid crystal photonic devices

Liquid crystal photonic devices are becoming increasingly popular. These devices often present a challenge when it comes to creating a robust alignment layer in pre-assembled cells. In this paper, we describe a method of infusing a dye into a microcavity to produce an effective photo-definable alignment layer. However, previous research on such alignment layers has shown that they have limited stability, particularly against subsequent light exposure. As such, we further describe a method of utilizing a pre-polymer, infused into the microcavity along with the liquid crystal, to provide photostability. We demonstrate that the polymer layer, formed under ultraviolet irradiation of liquid crystal cells, has been effectively localized to a thin region near the substrate surface and provides a significant improvement in the photostability of the liquid crystal alignment. This versatile alignment layer method, capable of being utilized in devices from the described microcavities to displays, offers significant promise for new photonics applications.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

A versatile setup using femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering

We report a versatile setup based on the femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering. The setup uses a femtosecond Ti:Sapphire oscillator source and a folded 4f pulse shaper, in which the pulse shaping is carried out through conventional optical elements and does not require a spatial light modulator. Our setup is simple in alignment, and can be easily switched between the collinear single-beam and the noncollinear two-beam configurations. We demonstrate the capability for investigating both transparent and highly scattering samples by detecting transmitted and reflected signals, respectively.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

Manipulating waves with LEGO{sup ®} bricks: A versatile experimental platform for metamaterial architectures

In this letter, we discuss a versatile, fully reconfigurable experimental platform for the investigation of phononic phenomena in metamaterial architectures. The approach revolves around the use of 3D laser vibrometry to reconstruct global and local wavefield features in specimens obtained through simple arrangements of LEGO{sup ®} bricks on a thin baseplate. The agility by which it is possible to reconfigure the brick patterns into a nearly endless spectrum of topologies makes this an effective approach for rapid experimental proof of concept, as well as a powerful didactic tool, in the arena of phononic crystals and metamaterials engineering. We use our platform to provide a compelling visual illustration of important spatial wave manipulation effects (waveguiding and seismic isolation), and to elucidate fundamental dichotomies between Bragg-based and locally resonant bandgap mechanisms.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Versatile magnetometer assembly for characterizing magnetic properties of nanoparticles

We constructed a versatile magnetometer assembly for characterizing iron oxide nanoparticles. The magnetometer can be operated at room temperature or inside a cryocooler at temperatures as low as 6 K. The magnetometer’s sensor can be easily exchanged and different detection electronics can be used. We tested the assembly with a non-cryogenic commercial Hall sensor and a benchtop multimeter in a four-wire resistance measurement scheme. A magnetic moment sensitivity of 8.5 × 10{sup −8} Am{sup 2} was obtained with this configuration. To illustrate the capability of the assembly, we synthesized iron oxide nanoparticles coated with different amounts of a triblock copolymer, Pluronic F-127, and characterized their magnetic properties. We determined that the polymer coating does not affect the magnetization of the particles at room temperature and demonstrates that it is possible to estimate the average size of coating layers from measurements of the magnetic field of the sample.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

A versatile dual-species Zeeman slower for caesium and ytterbium

We describe the design, construction, and operation of a versatile dual-species Zeeman slower for both Cs and Yb, which is easily adaptable for use with other alkali metals and alkaline earths. With the aid of analytic models and numerical simulation of decelerator action, we highlight several real-world problems affecting the performance of a slower and discuss effective solutions. To capture Yb into a magneto-optical trap (MOT), we use the broad {sup 1}S{sub 0} to {sup 1}P{sub 1} transition at 399 nm for the slower and the narrow {sup 1}S{sub 0} to {sup 3}P{sub 1} intercombination line at 556 nm for the MOT. The Cs MOT and slower both use the D2 line (6{sup 2}S{sub 1/2} to 6{sup 2}P{sub 3/2}) at 852 nm. The slower can be switched between loading Yb or Cs in under 0.1 s. We demonstrate that within a few seconds the Zeeman slower loads more than 10{sup 9} Yb atoms and 10{sup 8} Cs atoms into their respective MOTs. These are ideal starting numbers for further experiments on ultracold mixtures and molecules.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Electron density profile measurements from hydrogen line intensity ratio method in Versatile Experimental Spherical Torus

Electron density profiles of versatile experiment spherical torus plasmas are measured by using a hydrogen line intensity ratio method. A fast-frame visible camera with appropriate bandpass filters is used to detect images of Balmer line intensities. The unique optical system makes it possible to take images of H{sub α} and H{sub β} radiation simultaneously, with only one camera. The frame rate is 1000 fps and the spatial resolution of the system is about 0.5 cm. One-dimensional local emissivity profiles have been obtained from the toroidal line of sight with viewing dumps. An initial result for the electron density profile is presented and is in reasonable agreement with values measured by a triple Langmuir probe.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

A new H{sub 2}{sup +} source: Conceptual study and experimental test of an upgraded version of the VIS—Versatile ion source

The versatile ion source is an off-resonance microwave discharge ion source which produces a slightly overdense plasma at 2.45 GHz of pumping wave frequency extracting more than 60 mA proton beams and 50 mA He{sup +} beams. DAEδALUS and IsoDAR experiments require high intensities for H{sub 2}{sup +} beams to be accelerated by high power cyclotrons for neutrinos generation. In order to fulfill the new requirements, a new plasma chamber and injection system has been designed and manufactured for increasing the H{sub 2}{sup +} beam intensity. In this paper the studies for the increasing of the H{sub 2}{sup +}/p ratio and for the design of the new plasma chamber and injection system will be shown and discussed together with the experimental tests carried out at Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali del Sud (INFN-LNS) and at Best Cyclotron Systems test-bench in Vancouver, Canada.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Note: A versatile radio-frequency source for cold atom experiments

A radio-frequency (RF) source designed for cold atom experiments is presented. The source uses AD9858, a direct digital synthesizer, to generate the sine wave directly, up to 400 MHz, with sub-Hz resolution. An amplitude control circuit consisting of wideband variable gain amplifier and high speed digital to analog converter is integrated into the source, capable of 70 dB off isolation and 4 ns on-off keying. A field programmable gate array is used to implement a versatile frequency and amplitude co-sweep logic. Owing to modular design, the RF sources have been used on many cold atom experiments to generate various complicated RF sequences, enriching the operation schemes of cold atoms, which cannot be done by standard RF source instruments.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2017

Versatile strain-tuning of modulated long-period magnetic structures

In this paper, we report a detailed small-angle neutron scattering (SANS) study of the skyrmion lattice phase of MnSi under compressive and tensile strain. In particular, we demonstrate that tensile strain applied to the skyrmion lattice plane, perpendicular to the magnetic field, acts to destabilize the skyrmion lattice phase. Finally, this experiment was enabled by our development of a versatile strain cell, unique in its ability to select the application of either tensile or compressive strain in-situ by using two independent helium-actuated copper pressure transducers, whose design has been optimized for magnetic SANS on modulated long-period magnetic structures and vortex lattices, and is compact enough to fit in common sample environments such as cryostats and superconducting magnets.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

WAND 2 —A versatile wide angle neutron powder/single crystal diffractometer

Wide Angle Neutron Diffractometer Squared is a high-flux versatile diffractometer with a 2-Dimensional Position Sensitive Detector at the High Flux Isotope Reactor. The instrument has strengths in both powder and single crystal diffraction. It is a unique instrument in the neutron scattering landscape of North America, and its capabilities are at least equal to similar instruments in the world.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

A versatile Johansson-type tender x-ray emission spectrometer

We present a high energy resolution x-ray spectrometer for the tender x-ray regime (1.6–5.0 keV) that was designed and operated at Stanford Synchrotron Radiation Lightsource. The instrument is developed on a Rowland geometry (500 mm of radius) using cylindrically bent Johansson analyzers and a position sensitive detector. By placing the sample inside the Rowland circle, the spectrometer operates in an energy-dispersive mode with a subnatural line-width energy resolution (~0.32 eV at 2400 eV), even when an extended incident x-ray beam is used across a wide range of diffraction angles (~30° to 65°). The spectrometer is enclosed in a vacuum chamber, and a sample chamber with independent ambient conditions is introduced to enable a versatile and fast-access sample environment (e.g., solid/gas/liquid samples, in situ cells, and radioactive materials). The design, capabilities, and performance are presented and discussed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Versatile semi-batch apparatus for manometric measurement of gas–solid reaction rates

In this study, we describe the design, construction, operation, and performance of a simple and versatile semi-batch reactor that is especially useful for measurement of gas/solid reaction rates at pressures in the range of 1 mTorr to 1500 Torr. The reactor operates by repeatedly imposing small AC modulations of reactant gas pressure on top of a much larger DC pressure background. Based on the rate of pressure relaxation following each AC pulse, the reaction rate is determined. Our design is characterized by modular construction from off-the-shelf, ultra-high-vacuum-compatible components, which facilitate easy retrofitting and adaptation to a range of experimental conditions. Automated experiment control and data acquisition is accomplished via a custom National Instruments © LabView virtual instrument. Data analysis is automated using a custom series of Mathworks © Matlab scripts. We demonstrate reactor performance through measurements of hydrogenation kinetics for a composite H 2 getter material consisting of 1,4-bis(phenylethynyl)benzene mixed with a palladium/carbon catalyst.

47 OTHER INSTRUMENTATION↗
DOE OSTI2024

Versatile stochastic model for predictive KMC simulation of fcc metal nanostructure evolution with realistic kinetics

Stochastic lattice-gas models provide the natural framework for analysis of the surface diffusion-mediated evolution of crystalline metal nanostructures on the appropriate time scale (often 10 1 –10 4 s) and length scale. Model behavior can be precisely assessed by kinetic Monte Carlo simulation, typically incorporating a rejection-free algorithm to efficiently handle the broad range of Arrhenius rates for hopping of surface atoms. The model should realistically prescribe these rates, or the associated barriers, for a diversity of local surface environments. However, commonly used generic choices for barriers fail, even qualitatively, to simultaneously describe diffusion for different low-index facets, for terrace vs step edge diffusion, etc. We introduce an alternative Unconventional Interaction–Conventional Interaction formalism to prescribe these barriers, which, even with few parameters, can realistically capture most aspects of behavior. Here, the model is illustrated for single-component fcc metal systems, mainly for the case of Ag. It is quite versatile and can be applied to describe both the post-deposition evolution of 2D nanostructures in homoepitaxial thin films (e.g., reshaping and coalescence of 2D islands) and the post-synthesis evolution of 3D nanocrystals (e.g., reshaping of nanocrystals synthesized with various faceted non-equilibrium shapes back to 3D equilibrium Wulff shapes).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗