Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “ELECTRONIC MODULE”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Development of an electronically-scanned pressure module for operation at cryogenic temperatures

Pressure and temperature characteristics were measured for a number of multichannel electronically scanned pressure sensors. The tests were made on commercially available units designed to operate in a controlled temperature environment. Measurements of zero shift, sensitivity, and nonlinearity for each transducer were taken over a temperature range from 100 K to 340 K using a computer controlled data acquisition system. The units tested failed to meet accuracy specifications over the complete temperature range, which was expected. However, the sensors showed acceptable and predictable behavior over the temperature range from approximately -40 C (233 K) to 70 C (343 K). It was determined that a combination of local heating and accurate temperature monitoring can result in a device that can be compensated for temperature as well as its other physical properties. The design of a prototype for operation in a cryogenic environment is proposed, and a method for compensation is developed.

Johnson, Preston B.↗
NASA NTRS1974

High-resolution width-modulated pulse rebalance electronics for strapdown gyroscopes and accelerometers

Three different rebalance electronic loops were designed, implemented, and evaluated. The loops were width-modulated binary types using a 614.4 kHz keying signal; they were developed to accommodate the following three inertial sensors with the indicated resolution values: (1) Kearfott 2412 accelerometer - resolution = 260 micro-g/data pulse, (2) Honeywell GG334 gyroscope - resolution = 3.9 milli-arc-sec/data pulse, (3) Kearfott 2401-009 accelerometer - resolution = 144 milli-g/data pulse. Design theory, details of the design implementation, and experimental results for each loop are presented.

Kennedy, E. J.↗
DOE OSTI2014

Effect of collisional heat transfer in ICRF power modulation experiment on ASDEX Upgrade

ICRF (ion cyclotron range of frequencies) heating experiments were performed in D-H plasmas at various H concentrations on ASDEX Upgrade. The rf power was modulated to measure the electron power deposition profile from electron temperature modulation. To minimize the contribution from indirect collisional heating and the effect of radial transport, the rf power was modulated at 50 Hz. However, peaking of electron temperature modulation was still observed around the hydrogen cyclotron resonance indicating collisional heating contribution. Time dependent simulation of the hydrogen distribution function was performed for the discharges, using the full-wave code AORSA (E.F. Jaeger, et al., Phys. Plasmas, Vol. 8, page 1573 (2001)) coupled to the Fokker-Planck code CQL3D (R.W. Harvey, et al., Proc. IAEA (1992)). In the present experimental conditions, it was found that modulation of the collisional heating was comparable to that of direct wave damping. Impact of radial transport was also analyzed and found to appreciably smear out the modulation profile and reduce the phase delay.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Ion Emittance Growth Due to Focusing Modulation from Slipping Electron Bunch

Low energy RHIC operation has to be operated at an energy ranging from γ = 4.1 to γ = 10. The energy variation causes the change of revolution frequency. While the rf system for the circulating ion will operate at an exact harmonic of the revolution frequency (h=60 for 4.5 MHz rf and h=360 for 28 MHz rf.), the superconducting rf system for the cooling electron beam does not have a frequency tuning range that is wide enough to cover the required changes of revolution frequency. As a result, electron bunches will sit at different locations along the ion bunch from turn to turn, i.e. the slipping of the electron bunch with respect to the circulating ion bunch. At cooling section, ions see a coherent focusing force due to the electrons’ space charge, which differs from turn to turn due to the slipping. We will try to estimate how this irregular focusing affects the transverse emittance of the ion bunch.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

Diocotron modulation in an electron plasma through continuous radio-frequency excitation

The application of a radio-frequency (RF) excitation to any electrode of a Penning-Malmberg trap may result in significant electron heating and ionization of the residual gas with the formation of a plasma column when the RF frequency is of the order or larger than the typical axial bounce frequencies of few-eV electrons. The use of a quadrupolar excitation can induce additional phenomena, like formation of dense, narrow-cross section columns which exhibit an m{sub θ}=1 diocotron mode, i.e., a rotation of their center around the trap axis. A series of experiments is presented and discussed showing that the continuous application of such excitation causes a dramatic perturbation of the plasma equilibrium also involving continuous production and loss of particles in the trapping region. In particular, the growth of the first diocotron mode is suppressed even in the presence of ion resonance and resistive instability and the mode exhibits steady-state or underdamped amplitude and frequency modulations, typically in the Hertz range.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2014

The effect of plasma radius and profile on the development of self-modulation instability of electron bunches

Plasmas available for plasma wakefield accelerator experiments may have longitudinal and transverse density profiles that could affect the outcome of an experiment. This paper investigates the effect of plasmas with finite radius and inhomogeneous transverse density profiles on the wakefield excitation and the self-modulation instability (SMI) development in overdense plasmas. We focus here on the case of an electron bunch. Simulation results show that such plasmas generate larger focusing force for the propagating electron beam and therefore higher growth rate for the SMI. Although the initial accelerating field (E{sub z}) amplitude is lower in such plasmas, the increased focusing force can dominate the development trend of the SMI, i.e., larger saturated E{sub z} amplitude can be reached over similar plasma lengths.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2017

Possible Sources of Electron Neutrinos with a Modulated Monochromatic Component

A directed beam of electron neutrinos can be created by means of accumulating ions with β{sup +}-unstable nuclei in a storage ring. Such a neutrino beam may contain a significant monochromatic component, if these nuclei decay via electron capture with a sizable probability. Under specific conditions— in particular, in the case of employing hydrogen-like ions—this monochromatic component can be modulated. Requirements for β{sup +}-unstable nuclei of such hydrogen-like ions are discussed, and β{sup +}- decaying nuclides most appropriate for creating intense sources of electron neutrinos with amonochromatic component admitting modulation are indicated.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

Realization of Electron Antidoping by Modulating the Breathing Distortion in BaBiO 3

The recent proposal of antidoping scheme breaks new ground in conceiving conversely functional materials and devices; yet, the few available examples belong to the correlated electron systems. Here, we demonstrate both theoretically and experimentally that the main group oxide BaBiO 3 is a model system for antidoping using oxygen vacancies. The first-principles calculations show that the band gap systematically increases due to the strongly enhanced Bi-O breathing distortions away from the vacancies and the annihilation of Bi 6 s /O 2 p hybridized conduction bands near the vacancies. Our further spectroscopic experiments confirm that the band gap increases systematically with electron doping, with a maximal gap enhancement of ~75% when the film's stoichiometry is reduced to BaBiO 2.75 . These results unambiguously demonstrate the remarkable antidoping effect in a material without strong electron correlations and underscores the importance of bond disproportionation in realizing such an effect.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1977

Acceleration of nucleons in interplanetary space and modulation of Jovian electrons at distances of 1 to 10 AU by corotating regions of solar origin

Corotating interaction regions (CIRs) are formed in interplanetary space when a fast solar-plasma flow overtakes a slow solar-wind stream. This paper shows that CIRs are closely related to two unusual phenomena observed during the flights of Pioneers 10 and 11. These include corotating periodic nucleon fluxes with energies of several MeV and variations in the intensity of relativistic Jovian electrons. Observational evidence is presented in favor of the idea that the nucleons are accelerated in CIRs located in interplanetary space at heliocentric distances of 1 to at least 10 AU, and a model is analyzed in which the acceleration takes place at the leading edge of a CIR. Pioneer data are cited which demonstrate that modulation by recurrent CIRs can explain the large-scale variations in Jovian electron intensity observed in interplanetary space.

Barnes, C. W.↗
NASA NTRS1984

Electron mobility in modulation-doped heterostructures

A model for electron mobility in a two-dimensional electron gas confined in a triangular well was developed. All major scattering processes (deformation potential and piezoelectric acoustic, polar optical, ionized impurity, and alloy disorder) were included, as well as intrasubband and intersubband scattering. The model is applied to two types of modulation-doped heterostructures, namely GaAs-GaAlAs and In(0.53)Ga(0.47)As-Al(0.52)In(0.48)As. In the former case, phonons and remote ionized impurities ultimately limit the mobility, whereas in the latter, alloy disorder is a predominant scattering process at low temperatures. The calculated mobilities are in very good agreement with recently reported experimental characteristics for both GaAs-Ga(1-x)Al(x)As and In(0.53)Ga(0.47)As-Al(0.52)In(0.48)As modulation-doped heterostructures.

Walukiewicz, W.↗
DOE OSTI2014

Interfacial electronic structure-modulated magnetic anisotropy in Ta/CoFeB/MgO/Ta multilayers

We have observed several unexpected phenomena when a trace amount of Fe atoms is deposited onto the CoFeB/MgO interface in Ta/CoFeB/MgO/Ta multilayers. With the nominal thickness of the introduced Fe atoms (t{sub Fe}) varying from 0 to 0.1 Å, the effective magnetic anisotropy energy (K{sub eff}) of annealed multilayers is remarkably enhanced from 1.28 × 10{sup 6 }erg/cm{sup 3} to 2.14 × 10{sup 6 }erg/cm{sup 3}. As t{sub Fe} further increasing, the K{sub eff} decreases and even becomes negative when t{sub Fe} > 1 Å, indicating the change from perpendicular magnetic anisotropy to in-plane magnetic anisotropy. The analysis by X-ray photoelectron spectrometer reveals that the Fe atoms at annealed CoFeB/MgO interface show different electronic structures as t{sub Fe} increasing, which combine with O atoms to form FeO{sub x} (x < 1), Fe{sub 2}O{sub 3}, and Fe{sub 3}O{sub 4}, respectively, leading to modulation of Fe 3d-O 2p orbital hybridization and thus the K{sub eff}. On the other hand, we find that the introduction of Fe atoms also helps to reduce the multilayers' magnetic damping.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2013

Two-dimensional electron gas in a modulation-doped SrTiO{sub 3}/Sr(Ti, Zr)O{sub 3} heterostructure

A two-dimensional electron gas (2DEG) in SrTiO{sub 3} is created via modulation doping by interfacing undoped SrTiO{sub 3} with a wider-band-gap material, SrTi{sub 1−x}Zr{sub x}O{sub 3}, which is doped n-type with La. All layers are grown using hybrid molecular beam epitaxy. Using magnetoresistance measurements, we show that electrons are transferred into the SrTiO{sub 3}, and a 2DEG is formed. In particular, Shubnikov-de Haas oscillations are shown to depend only on the perpendicular magnetic field. Experimental Shubnikov-de Haas oscillations are compared with calculations that assume multiple occupied subbands.

36 MATERIALS SCIENCE↗
NASA NTRS2007

Miniature Intelligent Sensor Module

An electronic unit denoted the Miniature Intelligent Sensor Module performs sensor-signal-conditioning functions and local processing of sensor data. The unit includes four channels of analog input/output circuitry, a processor, volatile and nonvolatile memory, and two Ethernet communication ports, all housed in a weathertight enclosure. The unit accepts AC or DC power. The analog inputs provide programmable gain, offset, and filtering as well as shunt calibration and auto-zeroing. Analog outputs include sine, square, and triangular waves having programmable frequencies and amplitudes, as well as programmable amplitude DC. One innovative aspect of the design of this unit is the integration of a relatively powerful processor and large amount of memory along with the sensor-signalconditioning circuitry so that sophisticated computer programs can be used to acquire and analyze sensor data and estimate and track the health of the overall sensor-data-acquisition system of which the unit is a part. The unit includes calibration, zeroing, and signalfeedback circuitry to facilitate health monitoring. The processor is also integrated with programmable logic circuitry in such a manner as to simplify and enhance acquisition of data and generation of analog outputs. A notable unique feature of the unit is a cold-junction compensation circuit in the back shell of a sensor connector. This circuit makes it possible to use Ktype thermocouples without compromising a housing seal. Replicas of this unit may prove useful in industrial and manufacturing settings - especially in such large outdoor facilities as refineries. Two features can be expected to simplify installation: the weathertight housings should make it possible to mount the units near sensors, and the Ethernet communication capability of the units should facilitate establishment of communication connections for the units.

Beech, Russell S.↗
DOE OSTI2016

Comparison of Hybrid K-Edge Densitometer (HKED) Performance Operating with the Canberra Lynx MCA and the Canberra ICB-NIM Electronics

From the 1991 until 2008 the Canberra Hybrid K-Edge Densitometer systems were provided with ICB-NIM (Integrated Control Bus – Nuclear Instrument Module) acquisition electronics. Newer electronics modules, such as the Lynx, were not supported under the VMS based operating system. The LYNX module was provided as the standard acquisition electronics following the release of the Windows based CHKED software. This report compares the electronics dead-time, gain shifts, detector resolution and measurement performance of the HKED system operated with the two types of acquisition modules. The comparison was performed using measurements obtained with the ORNL HKED system. The original intent of this study was to take advantage of both the timing and energy outputs from the HPGE detector to acquire data with both sets of electronics in parallel. Although this approach has been applied successfully with other systems, in this case we found the timing output produced a significant amount of noise such that a comparison between the electronics would be invalid. So the comparative measurements were performed sequentially. The ICB-NIM data was acquired over the course of 12 months with 255 measurements while the LYNX data was acquired over a period of 10 months with 75 measurements. To simplify the comparison, all data used in this study was acquired using the Canberra CHKED (V1.0) software package. The performance analysis was based primarily on the peak locations, peak widths and concentration values reported by the CHKED software. The raw spectra from the XRF measurements were also examined to extract additional 109Cd peak location and width data for the hybrid measurements (the standard hybrid report template does not report these values).

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Status of Electronics Upgrades to the LANL Green is Clean Phoswich Detector Systems - 16419

Los Alamos National Laboratory radiological facilities produce low-density room trash that, in many cases, is not contaminated with radioactivity. It has been estimated that 50 to 90% of low-density room trash is free of radioactive contamination and eligible for inclusion in LANL's Green is Clean (GIC) program. The GIC program is a verification program for non-regulated waste from radiation controlled areas that has been actively segregated as nonradioactive through the use of the waste generator's acceptable knowledge. The GIC program has employed two large area Phoswich gamma ray detector systems (HERCULES and ZEUS) to assay and verify that GIC candidate waste meets free release disposal requirements. The large area (127 cm{sup 2}) Phoswich detectors consist of a thin NaI front crystal (3 mm thick) that is optically coupled to a thick CsI back crystal (50 mm thick). The crystals are set in an oxygen-free high-conductivity copper housing with a very thin (0.025 mm) aluminum entrance window. The scintillation properties of the two crystals are different enough to allow the system's electronic components to identify the origin of any pulse. The original systems utilize Nuclear Instrumentation Module (NIM) electronics to process the detector signals. These electronic modules provide the buffering, amplification, and pulse shape analyzer needed for the proper presentation of signals to the custom Phosmux router module. The router module separates the sodium iodide and cesium iodide signals by their rise times and transfers this information into the computer-mounted multichannel analyzer, a Canberra Model S-100 system. While these NIM Bin counting electronics configurations have been effective for approximately 20 years of operation, they are bulky requiring numerous modules per detector and the important Phosmux module is no longer manufactured by LANL. Modern advancement of commercial counting electronics now offer more compact options for equivalent detector signal processing. A pulse shape discriminator module, the DGF Pixie-4, made by XIA LLC, has been identified that can replace the majority of the original NIM bin electronics in a much more compact chassis - one Pixie-4 replaces four NIM amplifiers and four NIM PSAs and fits in a small National Instruments{sup TM} chassis. Thus, LANL has initiated a system upgrade project to replace the historic NIM electronics with the XIA Pixie4 and associated configuration software. The hardware for one Phoswich systems has been procured for the project and the configuration software, customized for the LANL Phoswich detector application, has been written by the manufacturer. Initial setup and optimization of the Pixie-4 configuration has been performed. Qualitative and quantitative baseline comparisons to the NIM electronics has been performed. Good agreement of key low energy gamma lines between the systems has allowed 'Proof of Concept' to be concluded. Further optimization and performance evaluations are in progress. Modifications to the LabVIEW{sup TM} based operating software (originally written by VI Control Systems Ltd.) are being performed by a LANL LabVIEW{sup TM} programmer to accommodate the electronics upgrade. A new LabVIEW{sup TM} interface to control the Pixie-4 has already been developed. Final optimization and testing, formal software QA, and revisions to operating procedures are in progress to achieve completion of the GIC system upgrade project. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗