55 Matching Results

Search Results

Advanced search parameters have been applied.

Analysis of the SIAM Infrared Acquisition System

Description: This report describes and presents the results of an analysis of the performance of the infrared acquisition system for a Self-Initiated Antiaircraft Missile (SIAM). A description of the optical system is included, and models of target radiant intensity, atmospheric transmission, and background radiance are given. Acquisition probabilities are expressed in terms of the system signal-to-noise ratio. System performance against aircraft and helicopter targets is analyzed, and background discrimination techniques are discussed. 17 refs., 22 figs., 6 tabs.
Date: February 1, 1974
Creator: Varnado, S.G.
Partner: UNT Libraries Government Documents Department

Evaluation of well-type Ge(Li) detectors for low-level radiochemical analysis

Description: Well-type Ge(Li) detectors have been evaluated for low-level gamma-ray spectrometry and radiochemical analyses. The detectors were found to have good resolution, high peak-to-Compton ratios and low backgrounds. The use of an anticoincidence shield further improves the detector performance. The detector efficiencies and backgrounds are compared with those obtained with other Ge(Li) detector systems. The well detectors were found to have better detection efficiencies and as low backgrounds as either large coaxial detectors or opposed detector systems. Sum-coincidence effects are more pronounced in the well detector and use of this feature is discussed. Applications which utilize the low-energy response of the detector are described. Minimum detectable activity levels were determined for several nuclides.
Date: September 1, 1977
Creator: Brauer, F. P. & Mitzlaff, W. A.
Partner: UNT Libraries Government Documents Department

Telluric-magnetotelluric survey at Mount Hood, Oregon: a preliminary study

Description: The survey was conducted as part of a geothermal resource assessment study that had the overall objective of stimulating geothermal exploration near stratovolcanoes in the High Cascade Range. A telluric-magnetotelluric (T-MT) survey was chosen as the electrical resistivity technique. Data were collected in overlapping bands from 0.002 to 40 Hz, although high levels of cultural noise, coupled with instrumental problems, decreased the usable high frequency response during the first phase of the two-phase field program. Two specific areas of interest have been identified: (a) Two anomalous near-surface low-resistivity zones occur close to the Cloud Cap eruptive center on the northeast side of the volcano. Anomalous conditions diminish away from the recent (12,000/sup +-/ y.B.P.) vent. The shallower zone (0.5 to 1.0 km in depth) occurs within the Mount Hood volcanic pile and its 2 ohm-m resistivity is difficult to explain. A deeper zone (2/sup +-/ km), of approximately 10 ohm-m, occurs within what may be the pre-Mount Hood Yakima basalts (Miocene), and may have geothermal potential. (b) The strongly linear north-south electric field polarizations observed on the south side could be significant. Warm water emanations in the area suggest faulting, but there is neither direct evidence for faults, nor do the MT results clearly indicate anomalous resistivity conditions at depth. The MT station closest to the warm springs yielded low apparent resistivities which could be explained by conductive rock extending from surface to an undetermined depth. However, these data are incomplete and suspect, both because of severe noise and recorder malfunction at higher frequencies.
Date: June 1, 1978
Creator: Goldstein, N.E. & Mozley, E.
Partner: UNT Libraries Government Documents Department

Zeeman atomic absorption spectrometry

Description: The design and development of a Zeeman atomic absorption spectrometer for trace element analysis are described. An instruction manual is included which details the operation, adjustment, and maintenance. Specifications and circuit diagrams are given. (WHK)
Date: August 1, 1978
Creator: Hadeishi, T. & McLaughlin, R.
Partner: UNT Libraries Government Documents Department

Noise considerations in millimeter-wave spectrometers

Description: An improved version of a microwave spectrometer operating in the vicinity of 70 GHz is described. The spectrometer, which incorporates a Fabry-Perot resonator and superheterodyne detection for high sensitivity is designed for the detection of gaseous pollutants and other atmospheric constituents. The instrument is capable of detecting polar molecules with absorption coefficients as small as 2 x 10/sup -9/cm/sup -1/. For sulphur dioxide diluted in air, this sensitivity corresponds to a detection limit of 1.2 ppm without preconcentration and with a time constant of 1 second. Measurements and analysis of the noise contributions limiting the sentivity are presented.
Date: December 1, 1978
Creator: Zoellner, W.D.; Kolbe, W.F. & Leskovar, B.
Partner: UNT Libraries Government Documents Department

Search for parity-violating contributions to scattering of hadrons. [800 MeV, preliminary results helicity, asymmetry]

Description: The study of parity violation is, at present, the only means of studying the weak nonleptonic strangness conserving nucleon-nucleon force at medium energies. The experiment is a search for parity nonconservation in p-nucleus scattering by observing a change in the total cross section as the helicity of the incident protons is reversed. A nonvanishing helicity dependent cross section, A = (sigma/sub +/ - sigma/sub -//sigma/sub +/ + sigma/sub -/) would imply the presence of a parity-violating interaction. The experiment utilized the 800-MeV longitudinally polarized external proton beam at the Clinton P. Anderson Meson Physics Facility of the Los Alamos Scientific Laboratory. The result of the most recent run, March 1979, is as follows: no parity violation is observed: A = -2.5 +- 3.2 x 10/sup -6/. The systematic error contributions are not greater than 0.5 x 10/sup -6/. 2 references.
Date: January 1, 1979
Creator: Ziskind, J.; Yuan, V. & Mischke, R.
Partner: UNT Libraries Government Documents Department

Geothermal Loan Guarantee Program: Westmorland Development Project, Imperial County, California: Environmental assessment

Description: The action assessed is the guaranty of a loan by DOE to finance geothermal exploration, development, and testing by Mapco Geothermal, Inc. and Republic Geothermal, Inc. in the Westmorland area of Imperial County, California. Initial drilling and flow testing of up to three production wells will occur in the exploratory phase. Exploration is proposed for either or both of two portions of the leasehold area. If exploration confirms the presence of a viable resource in the Sweetwater area, the preferred site based on limited temperature data, then up to 19 new production wells and three new injection wells may be drilled and tested there in preparation for the construction of a 55-MW double-flash electric power plant. If, however, the Sweetwater resource proves infeasible, further exploration and possible full-field development may occur instead at the Dearborn-Kalin-Landers area. At this site, up to 19 new production wells and three new injection wells may be drilled and tested, with six existing wells also used for injection. This environmental assessment chiefly addresses effects of the drilling and testing program. In summary, this paper discusses the proposed action, describes the existing environment and discusses the potential environmental impacts. 75 refs. (LSP)
Date: April 1, 1979
Partner: UNT Libraries Government Documents Department

Signals for tau neutrino events in a beam dump experiment

Description: Ways of detecting tau neutrinos emerging from a beam dump are studied. Key signatures are elaborated and contrasted with background arising from muon and electron neutrino interactions. Expected event rates are given for various neutrino spectra. 16 references.
Date: May 1, 1979
Creator: Albright, C.H.; Shrock, R.E. & Smith, J.
Partner: UNT Libraries Government Documents Department

Identification, detection, and validation of vibrating structures: a signal processing approach

Description: This report discusses the application of modern signal processing techniques to characterize parameters governing the vibrational response of a structure. Simulated response data is used to explore the feasibility of applying these techniques to various structural problems. On-line estimator/indentifiers are used to estimate structural parameters, validate designed structures, and detect structural failure when used with a detector.
Date: September 18, 1979
Creator: Candy, J.V. & Lager, D.L.
Partner: UNT Libraries Government Documents Department

Analytical transmission electron microscopy in materials science

Description: Microcharacterization of materials on a scale of less than 10 nm has been afforded by recent advances in analytical transmission electron microscopy. The factors limiting accurate analysis at the limit of spatial resolution for the case of a combination of scanning transmission electron microscopy and energy dispersive x-ray spectroscopy are examined in this paper.
Date: January 1, 1980
Creator: Fraser, H.L.
Partner: UNT Libraries Government Documents Department

Background fitting for electron energy-loss spectra

Description: Microanalysis using electron energy loss spectroscopy is now well established. In order to assess true edge profiles and obtain integrated intensities of the inner shell ionization edges of interest, it is first necessary to subtract the background. Usually a simple inverse power law is used, but for some spectra this form does not fit well. An alternative form which results in superior fits is described.
Date: January 1, 1981
Creator: Bentley, J.; Lehman, G.L. & Sklad, P.S.
Partner: UNT Libraries Government Documents Department

Effect of resonant microwave power on a PIG ion source

Description: We have investigated the effect of applying microwave power at the electron cyclotron frequency on the characteristics of the ion beam extracted from a hot-cathode PIG ion source. No change was seen in the ion charge state distribution. A small but significant reduction in the beam noise level was seen, and it is possible that the technique may find application in situations where beam quiescence is important. 29 references, 2 figures.
Date: August 1, 1984
Creator: Brown, I.G.; Galvin, J.E.; Gavin, B.F. & MacGill, R.A.
Partner: UNT Libraries Government Documents Department

Background-reducing x-ray multilayer mirror

Description: This invention is comprised of a background-reducing x-ray multilayer mirror. A multiple-layer ``wavetrap`` deposited over the surface of a layered synthetic microstructure soft x-ray mirror optimized for reflectivity at chosen wavelengths is disclosed for reducing the reflectivity of undesired, longer wavelength incident radiation incident thereon. In three separate mirror designs employing an alternating molybdenum and silicon layered mirrored structure overlaid by two layers of a molybdenum/silicon pair anti-reflection coating, reflectivities of near normal incidence 133, 171, and 186 {Angstrom} wavelengths have been optimized, while that at 304 {Angstrom} has been minimized. The optimization process involves the choice of materials, the composition of the layer/pairs as well as the number thereof, and the distance therebetween for the mirror, and the simultaneous choice of materials, the composition of the layer/pairs, their number and distance for the ``wavetrap.``
Date: August 3, 1990
Creator: Bloch, J. J.; Roussel-Dupre, D. & Smith, B. W.
Partner: UNT Libraries Government Documents Department

The NSLS 100 element solid state array detector

Description: X-ray absorption studies of dilute samples require fluorescence detection techniques. Since signal-to-noise ratios are governed by the ratio of fluorescent to scattered photons counted by a detector, solid state detectors which can discriminate between fluorescence and scattered photons have become the instruments of choice for trace element measurements. Commercially available 13 element Ge array detectors permitting total count rates < 500,000 counts per second are now in routine use. Since x-ray absorption beamlines at high brightness synchrotron sources can already illuminate most dilute samples with enough flux to saturate the current generation of solid state detectors, the development of next-generation instruments with significantly higher total count rates is essential. We present the design and current status of the 100 element Si array detector being developed in a collaboration between the NSLS and the Instrumentation Division at Brookhaven National Laboratory. The detecting array consists of a 10*10 matrix of 4mm * 4mm elements laid out on a single piece of ultra-high purity silicon mounted at the front end of a liquid nitrogen dewar assembly. A matrix of charge sensitive integrating preamplifiers feed signals to an array of shaping amplifiers, single channel analyzers, and scalers. An electronic switch, delay amplifier, linear gate, digital scope, peak sensing A to D converter, and histogramming memory module provide for complete diagnostics and channel calibration. The entire instrument is controlled by a LabView 2 application on a MacII ci; the software also provides full control over beamline hardware and performs the data collection.
Date: January 1, 1991
Creator: Furenlid, L.R.; Kraner, H.W.; Rogers, L.C.; Stephani, D.; Beuttenmuller, R.H.; Beren, J. (Brookhaven National Lab., Upton, NY (United States)) et al.
Partner: UNT Libraries Government Documents Department

Noise reduction in negative-ion quadrupole mass spectrometry

Description: This invention is comprised of a quadrupole mass spectrometer (QMS) system having an ion source, quadrupole mass filter, and ion collector/recorder system. A weak, transverse magnetic field and an electron collector are disposed between the quadrupole and ion collector. When operated in negative ion mode, the ion source produces a beam of primarily negatively-charged particles from a sample, including electrons as well as ions. The beam passes through the quadrupole and enters the magnetic field, where the electrons are deflected away from the beam path to the electron collector. The negative ions pass undeflected to the ion collector where they are detected and recorded as a mass spectrum.
Date: December 31, 1991
Creator: Chastagner, P.
Partner: UNT Libraries Government Documents Department

The NSLS 100 element solid state array detector

Description: X-ray absorption studies of dilute samples require fluorescence detection techniques. Since signal-to-noise ratios are governed by the ratio of fluorescent to scattered photons counted by a detector, solid state detectors which can discriminate between fluorescence and scattered photons have become the instruments of choice for trace element measurements. Commercially available 13 element Ge array detectors permitting total count rates < 500,000 counts per second are now in routine use. Since x-ray absorption beamlines at high brightness synchrotron sources can already illuminate most dilute samples with enough flux to saturate the current generation of solid state detectors, the development of next-generation instruments with significantly higher total count rates is essential. We present the design and current status of the 100 element Si array detector being developed in a collaboration between the NSLS and the Instrumentation Division at Brookhaven National Laboratory. The detecting array consists of a 10*10 matrix of 4mm * 4mm elements laid out on a single piece of ultra-high purity silicon mounted at the front end of a liquid nitrogen dewar assembly. A matrix of charge sensitive integrating preamplifiers feed signals to an array of shaping amplifiers, single channel analyzers, and scalers. An electronic switch, delay amplifier, linear gate, digital scope, peak sensing A to D converter, and histogramming memory module provide for complete diagnostics and channel calibration. The entire instrument is controlled by a LabView 2 application on a MacII ci; the software also provides full control over beamline hardware and performs the data collection.
Date: December 31, 1991
Creator: Furenlid, L. R.; Kraner, H. W.; Rogers, L. C.; Stephani, D.; Beuttenmuller, R. H.; Beren, J. et al.
Partner: UNT Libraries Government Documents Department

Readily implemented enhanced sinusoid detection in noise

Description: Significant efforts have been devoted, spanning many years, to the problem of sinusoid detection in noise. Many of these efforts have produced superb, yet complex, algorithms which may be difficult to use for a wide segment of the Digital Signal Processing (DSP) community. This paper presents a simple, easily implemented and high effective method which solves this problem. This method severely degrades non-sinusoidal noise while leaving the embedded sinusoid(s) relatively undisturbed. The algorithm, simply put, exploits the difference between the net effect of integration and differentiation of sinusoids versus the effect of these operations on random noise and other signal sequences. The cross-correlation of sine wave with its differentiated (and/or integrated) self is quite high. Conversely, the cross-reduction of a noise sequence with its differentiated (and/or integrated) self is much lower. Therefore, it is reasonable to assume that for sequences consisting of a sinusoid in noise, significant signal-to-noise-ratios (SNRs) in the correlation results are achievable using a combination of differentiation (and/or integration) and cross-correlation operations on such sequences. This technique has been applied to actual Doppler radar data, as well as to synthesized data, with excellent improvement in signal detection capability. 4 refs.
Date: March 5, 1992
Creator: Lindsay, K.V.
Partner: UNT Libraries Government Documents Department