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Sample records for gamma spectrum analysis

  1. Frequency spectrum analysis for spectrum stabilization in airborne gamma-ray spectrometer.

    PubMed

    Zeng, Guoqiang; Tan, Chengjun; Ge, Liangquan; Zhang, Qingxian; Gu, Yi

    2014-02-01

    Abnormal multi-crystal spectral drifts often can be observed when power on the airborne gamma-ray spectrometer. Currently, these spectral drifts of each crystal are generally eliminated through manual adjustment, which is time-consuming and labor-ineffective. To realize this quick automatic spectrum stabilization of multi-crystal, a frequency spectrum analysis method for natural gamma-ray background spectrum is put forward in this paper to replace traditional spectrum stabilization method used characteristic peak. Based on the polynomial fitting of high harmonics in frequency spectrum and gamma-ray spectral drift, it calculates overall spectral drift of natural gamma-ray spectrum and adjusts the gain of spectrometer by this spectral drift value, thus completing quick spectrum stabilization in the power on stage of spectrometer. This method requires no manual intervention and can obtain the overall spectral drift value automatically under no time-domain pre-processing to the natural gamma-ray spectra. The spectral drift value calculated by this method has an absolute error less than five channels (1024 resolution) and a relative error smaller than 0.80%, which can satisfy the quick automatic spectrum stabilization requirement when power on the airborne gamma-ray spectrometer instead of manual operation.

  2. Gamma-ray pulse height spectrum analysis on systems with multiple Ge detectors using spectrum summing

    SciTech Connect

    Killian, E.W.

    1997-11-01

    A technique has been developed at the Idaho National Engineering Laboratory to sum high resolution gamma-ray pulse spectra from systems with multiple Ge detectors. Lockheed Martin Idaho Technologies Company operates a multi-detector spectrometer configuration at the Stored Waste Examination Pilot Plant facility which is used to characterize the radionuclide contents in waste drums destined for shipment to Waste Isolation Pilot Plant. This summing technique was developed to increase the sensitivity of the system, reduce the count times required to properly quantify the radio-nuclides and provide a more consistent methodology for combining data collected from multiple detectors. In spectrometer systems with multiple detectors looking at non homogeneous waste forms it is often difficult to combine individual spectrum analysis results from each detector to obtain a meaningful result for the total waste container. This is particularly true when the counting statistics in each individual spectrum are poor. The spectrum summing technique adds the spectra collected by each detector into a single spectrum which has better counting statistics than each individual spectrum. A normal spectral analysis program can then be used to analyze the sum spectrum to obtain radio-nuclide values which have smaller errors and do not have to be further manipulated to obtain results for the total waste container. 2 refs., 2 figs.

  3. Gamma-Ray Spectrum Analysis Method for Minicomputers.

    1984-01-24

    Version 00 SAMPO80 is a rapid and accurate analysis program for gamma-ray spectra measured with Ge(Li) or HPGe detectors. SAMPO80 consists of three separate parts, the shape calibration part SAMPOSHAPE, the peak search and fitting part SAMPOFIT, and the nuclide identification part SAMPOID.

  4. TPASS: a gamma-ray spectrum analysis and isotope identification computer code

    SciTech Connect

    Dickens, J.K.

    1981-03-01

    The gamma-ray spectral data-reduction and analysis computer code TPASS is described. This computer code is used to analyze complex Ge(Li) gamma-ray spectra to obtain peak areas corrected for detector efficiencies, from which are determined gamma-ray yields. These yields are compared with an isotope gamma-ray data file to determine the contributions to the observed spectrum from decay of specific radionuclides. A complete FORTRAN listing of the code and a complex test case are given.

  5. A de-noising algorithm to improve SNR of segmented gamma scanner for spectrum analysis

    NASA Astrophysics Data System (ADS)

    Li, Huailiang; Tuo, Xianguo; Shi, Rui; Zhang, Jinzhao; Henderson, Mark Julian; Courtois, Jérémie; Yan, Minhao

    2016-05-01

    An improved threshold shift-invariant wavelet transform de-noising algorithm for high-resolution gamma-ray spectroscopy is proposed to optimize the threshold function of wavelet transforms and reduce signal resulting from pseudo-Gibbs artificial fluctuations. This algorithm was applied to a segmented gamma scanning system with large samples in which high continuum levels caused by Compton scattering are routinely encountered. De-noising data from the gamma ray spectrum measured by segmented gamma scanning system with improved, shift-invariant and traditional wavelet transform algorithms were all evaluated. The improved wavelet transform method generated significantly enhanced performance of the figure of merit, the root mean square error, the peak area, and the sample attenuation correction in the segmented gamma scanning system assays. We also found that the gamma energy spectrum can be viewed as a low frequency signal as well as high frequency noise superposition by the spectrum analysis. Moreover, a smoothed spectrum can be appropriate for straightforward automated quantitative analysis.

  6. Gamma-ray pulse height spectrum analysis on systems with multiple Ge detectors using a spectrum summing

    SciTech Connect

    Killian, E.W.

    1997-05-01

    A technique has been developed at the Idaho National Engineering Laboratory to sum high resolution gamma-ray pulse spectra from systems with multiple Ge detectors. Lockheed Martin Idaho Technologies Company operates a multi-detector spectrometer configuration at the Stored Waste Examination Pilot Plant facility which is used to characterize the radio nuclide contents in waste drums destined for shipment to Waste Isolation Pilot Plant. This summing technique was developed to increase the sensitivity of the system, reduce the count times required to properly quantify the radionuclides and provide a more consistent methodology for combining data collected from multiple detectors. In spectrometer systems with multiple detectors looking at non homogenous waste forms it is often difficult to combine individual spectrum analysis results from each detector to obtain a meaningful result for the total waste container. This is particularly true when the counting statistics in each individual spectrum are poor. The spectrum summing technique adds the spectra collected by each detector into a single spectrum which has better counting statistics than each individual spectrum. A normal spectral analysis program can then be used to analyze the sum spectrum to obtain radio nuclide values which have smaller errors and do not have to be further manipulated to obtain results for the total waste container.

  7. Design of a program in Matlab environment for gamma spectrum analysis of geological samples

    NASA Astrophysics Data System (ADS)

    Rojas, M.; Correa, R.

    2016-05-01

    In this work we present the analysis of gamma ray spectra Ammonites found in different places. One of the fossils was found near the city of Cusco (Perú) and the other in “Cajón del Maipo” in Santiago (Chile). Spectra were taken with a hyperpure germanium detector (HPGe) in an environment cooled with liquid nitrogen, with the technique of high-resolution gamma spectroscopy. A program for automatic detection and classifying of the samples was developed in Matlab. It program has the advantage of being able to make direct interventions or generalize it even more, or make it automate for specific spectra and make comparison between them. For example it can calibrate the spectrum automatically, only by giving the calibration spectrum, without the necessity of putting them. Finally, it also erases the external noise.

  8. Spectrum shape-analysis techniques applied to the Hanford Tank Farms spectral gamma logs

    SciTech Connect

    Wilson, R.D.

    1997-05-01

    Gamma-ray spectra acquired with high-energy resolution by the spectral gamma logging systems (SGLSs) at the U.S. Department of Energy Hanford Tank Farms, Richland, Washington, are being analyzed for spectral shape characteristics. These spectral shapes, together with a conventional peak-area analysis, enable an analyst not only to identify the gamma-emitting species but also to determine in many instances its spatial distribution around a borehole and to identify the presence of the bremsstrahlung-producing contaminant {sup 90}Sr. The analysis relies primarily on the results of computer simulations of gamma spectra from the predominant radionuclide {sup 137}Cs for various spatial distributions. This log analysis methodology has evolved through an examination of spectral features from spectral logs taken at the SX, BY, and U Tank Farms at the Hanford Site. Initial results determined with this technique show it is possible, in most cases, to distinguish between concentrations of {sup 137}Cs. Work is continuing by experimentally measuring shape factors, incorporating spectrum shape processing in routine log analysis, and extending the techniques to additional radionuclides.

  9. Operator's guide for VAXGAP, a gamma-ray spectrum analysis package

    SciTech Connect

    Killian, E.W.; Femec, D.A.

    1992-08-01

    This report describes the gamma-ray analysis program VAXGAP, which has continually evolved at the Idaho National Engineering Laboratory over a period of several years. It is an integrated suite of computer programs for performing analyses of pulse-height spectra from high-resolution gamma-ray spectrometers and assorted support functions. VAXGAP programs operate on Digital Equipment Corporation (DEC) VAX computers running the VMS operating system, and were written in VAX FORTRAN and DEC Digital Command Language (DCL). These programs make use of DEC GKS and ReGIS for graphical output on standard terminals and printers, and DEC windows for graphics on workstations and terminals that support the X Window System protocol. This report addresses the use of VAXGAP for data acquisition and control, energy scale calibration, and real-time analyses of background and sample pulse-height spectra. Also addressed are the creation and use efficiency tables and isotope libraries, manipulation of spectrum files and their contents, and graphical display of on-going acquisitions, saved spectra, and mathematical fits to spectral peaks.

  10. Operator`s guide for VAXGAP, a gamma-ray spectrum analysis package

    SciTech Connect

    Killian, E.W.; Femec, D.A.

    1992-08-01

    This report describes the gamma-ray analysis program VAXGAP, which has continually evolved at the Idaho National Engineering Laboratory over a period of several years. It is an integrated suite of computer programs for performing analyses of pulse-height spectra from high-resolution gamma-ray spectrometers and assorted support functions. VAXGAP programs operate on Digital Equipment Corporation (DEC) VAX computers running the VMS operating system, and were written in VAX FORTRAN and DEC Digital Command Language (DCL). These programs make use of DEC GKS and ReGIS for graphical output on standard terminals and printers, and DEC windows for graphics on workstations and terminals that support the X Window System protocol. This report addresses the use of VAXGAP for data acquisition and control, energy scale calibration, and real-time analyses of background and sample pulse-height spectra. Also addressed are the creation and use efficiency tables and isotope libraries, manipulation of spectrum files and their contents, and graphical display of on-going acquisitions, saved spectra, and mathematical fits to spectral peaks.

  11. Proximal Gamma-Ray Spectroscopy to Predict Soil Properties Using Windows and Full-Spectrum Analysis Methods

    PubMed Central

    Mahmood, Hafiz Sultan; Hoogmoed, Willem B.; van Henten, Eldert J.

    2013-01-01

    Fine-scale spatial information on soil properties is needed to successfully implement precision agriculture. Proximal gamma-ray spectroscopy has recently emerged as a promising tool to collect fine-scale soil information. The objective of this study was to evaluate a proximal gamma-ray spectrometer to predict several soil properties using energy-windows and full-spectrum analysis methods in two differently managed sandy loam fields: conventional and organic. In the conventional field, both methods predicted clay, pH and total nitrogen with a good accuracy (R2 ≥ 0.56) in the top 0–15 cm soil depth, whereas in the organic field, only clay content was predicted with such accuracy. The highest prediction accuracy was found for total nitrogen (R2 = 0.75) in the conventional field in the energy-windows method. Predictions were better in the top 0–15 cm soil depths than in the 15–30 cm soil depths for individual and combined fields. This implies that gamma-ray spectroscopy can generally benefit soil characterisation for annual crops where the condition of the seedbed is important. Small differences in soil structure (conventional vs. organic) cannot be determined. As for the methodology, we conclude that the energy-windows method can establish relations between radionuclide data and soil properties as accurate as the full-spectrum analysis method. PMID:24287541

  12. Proximal gamma-ray spectroscopy to predict soil properties using windows and full-spectrum analysis methods.

    PubMed

    Mahmood, Hafiz Sultan; Hoogmoed, Willem B; van Henten, Eldert J

    2013-11-27

    Fine-scale spatial information on soil properties is needed to successfully implement precision agriculture. Proximal gamma-ray spectroscopy has recently emerged as a promising tool to collect fine-scale soil information. The objective of this study was to evaluate a proximal gamma-ray spectrometer to predict several soil properties using energy-windows and full-spectrum analysis methods in two differently managed sandy loam fields: conventional and organic. In the conventional field, both methods predicted clay, pH and total nitrogen with a good accuracy (R2 ≥ 0.56) in the top 0-15 cm soil depth, whereas in the organic field, only clay content was predicted with such accuracy. The highest prediction accuracy was found for total nitrogen (R2 = 0.75) in the conventional field in the energy-windows method. Predictions were better in the top 0-15 cm soil depths than in the 15-30 cm soil depths for individual and combined fields. This implies that gamma-ray spectroscopy can generally benefit soil characterisation for annual crops where the condition of the seedbed is important. Small differences in soil structure (conventional vs. organic) cannot be determined. As for the methodology, we conclude that the energy-windows method can establish relations between radionuclide data and soil properties as accurate as the full-spectrum analysis method.

  13. Analysis of variable VHE gamma-ray emission from the hard spectrum blazar 1ES 1218+304

    NASA Astrophysics Data System (ADS)

    Imran, Asif

    This thesis is a study of the very high energy gamma-ray emission from the hard spectrum blazar 1ES 1218+304. The data were collected during the 2008/09 observing season by the VERITAS observatory, an array of four atmospheric Cherenkov telescopes in Southern Arizona. This work describes the development of a set of analysis tools suitable for the extraction of the energy spectra of astrophysical objects. Initially, the tools are applied to the Crab nebula data to optimize and calibrate the analysis. Afterwards, the analysis is applied to the high energy observations of the blazar 1ES 1218+304. We report an intense, day-scale flare observed on January 30, 2009. This marks the first detection of variability in gamma-ray emission from 1ES 1218+304. I also investigate the possibility of detecting a spectral feature in the observed energy spectra of blazar due to extragalactic background light. I demonstrate the presence of a spectral cut-off in the simulated multi-TeV energy spectra of blazars at around 1 TeV. This novel technique has a strong potential to discover the first observable signature of absorption of very high-energy photons due to the extragalactic background light.

  14. SYNTH - Gamma Ray Spectrum Synthesizer

    2009-05-18

    SYNTH was designed to synthesize the results of typical gamma-ray spectroscopy experiments. The code allows a user to specify the physical characteristics of a gamma-ray source, the quantity of radionuclides emitting gamma radiation, the source-to-detector distance and the presence and type of any intervening absorbers, the size and type of the gamma-ray detector, and the electronic set-up used to gather the data.

  15. Full spectrum analysis in environmental monitoring.

    PubMed

    Reinhardt, Sascha

    2014-08-01

    In environmental radiation monitoring, the time-variable natural gamma radiation background complicates the nuclide identification and analysis of a gamma spectrum. A full spectrum analysis based on the noise adjusted singular value decomposition method for the description of the time-variable background and adjustment calculations is a possible analysis method, which may provide advantages compared with a peak-based analysis, if applied to a time series of gamma spectra. An analysis example is shown and discussed with a measured time series of gamma spectra obtained from a spectroscopic gamma detector with a NaI(Tl) scintillator as it is used in the environmental radiation monitoring.

  16. Atypical Laterality of Resting Gamma Oscillations in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Maxwell, Christina R.; Villalobos, Michele E.; Schultz, Robert T.; Herpertz-Dahlmann, Beate; Konrad, Kerstin; Kohls, Gregor

    2015-01-01

    Abnormal brain oscillatory activity has been found in autism spectrum disorders (ASD) and proposed as a potential biomarker. While several studies have investigated gamma oscillations in ASD, none have examined resting gamma power across multiple brain regions. This study investigated resting gamma power using EEG in 15 boys with ASD and 18 age…

  17. Gamma-band abnormalities as markers of autism spectrum disorders

    PubMed Central

    Rojas, Donald C.; Wilson, Lisa B.

    2014-01-01

    Summary Autism is a behaviorally diagnosed neurodevelopmental disorder with no current biomarkers with high specificity and sensitivity. Gamma-band abnormalities have been reported in many studies of autism spectrum disorders. Gamma-band activity is associated with perceptual and cognitive functions that are compromised in autism. Some gamma-band deficits have also been seen in unaffected first-degree relatives, suggesting heritability of these findings. This review covers the published literature on gamma abnormalities in autism, the proposed mechanisms underlying the deficits, and the potential for translation into new treatments. Although the utility of gamma-band metrics as diagnostic biomarkers is currently limited, such changes in autism are also useful as endophenotypes, for evaluating potential neural mechanisms, and for use as surrogate markers of treatment response to interventions. PMID:24712425

  18. MGA: A gamma-ray spectrum analysis code for determining plutonium isotopic abundances. Volume 3, FORTRAN listing of the GA code

    SciTech Connect

    Gunnink, R

    1991-09-01

    Nondestructive measurements of x-ray and gamma-ray emissions can be used to determine the abundances of various actinides in a sample. Volume 1 of this report describes the methods and algorithms we have developed to determine the relative isotopic abundances of actinides in a sample, by analyzing gamma-ray spectra obtained using germanium detector systems. Volume 2 is a guide to using the MGA (Multiple Group Analysis) computer program we have written to perform plutonium isotopic analyses. This report contains a listing of the FORTRAN instructions of the code.

  19. Gamma Ray Spectrum Catalogs from Idaho National Laboratory (INL)

    DOE Data Explorer

    Heath, R. L.

    Gamma-ray spectrometry is widely applied as a tool for the assay of radioactive source material to identify the isotopes present and characterize radiation fields. Beginning with the startup of the world's first high-flux beam reactor, Materials Test Reactor (MTR), INL has pioneered the development of x-ray spectrometry for use in basic nuclear research and a variety of disciplines using radioisotopes and other radiation sources. Beginning in the early 1950s, a program was instituted to make the technique a precise laboratory tool. Standards were established for detectors and nuclear electronics to promote the production of commercial laboratory spectrometers. It was also necessary to produce a comprehensive collection of standard detector response functions for individual radio nuclides to permit the use of gamma-ray spectrometers for identification of radioisotopes present in radiation sources. This led to the publication of standard measurement methodology and a set of Gamma-Ray Spectrum Catalogues. These publications, which established standards for detector systems, experimental methods and reference spectra for both NaI (Tl) scintillation detectors and Ge(Li) - Si( Li) semiconductor devices, became standard reference works, distributed worldwide. Over 40,000 copies have been distributed by the Office of Science and Technical Information (OSTI). Unfortunately, although they are still very much in demand, they are all out of print at this time. The INL is converting this large volume of data to a format which is consistent with current information technology and meets the needs of the scientific community. Three are available online with the longest being more than 800 pages in length. Plotted spectra and decay data have been converted to digital formats and updated, including decay scheme graphics. These online catalogs are: • Ge(Li)-Si(Li) Gamma Spectrum Catalog (Published 3-29-1999) • NaI(Tl) Gamma Spectrum Catalog (Published 4-1-1997) • Gamma

  20. The U.S. Spectrum X Gamma Coordination Facility

    NASA Technical Reports Server (NTRS)

    Forman, William R.

    1999-01-01

    Spectrum-X-Gamma (SXG) provides for US participation in a first-class international x-ray mission. Despite launch delays, SXG will provide unique scientific opportunities due to its capability for all-sky monitoring, polarimetry, high resolution spectroscopy, and broad wavelength range-from the ultraviolet (TAUVEX and FUVITA), through the x-ray (SODART and JET-X), to the hard x-ray (MART), and gamma-ray burst detectors. Before describing our completed work, we review the unique properties of SXG and provide some examples of the scientific importance of SXG in the Chandra, XMM, and ASTRO-E era.

  1. Acoustooptical spectrum analysis modeling

    NASA Astrophysics Data System (ADS)

    Carmody, M. J.

    1981-06-01

    A summary of Bragg deflection theory and various approaches to direct detection acoustooptic spectrum analysis (AOSA) modeling is presented. A suitable model is chosen and extended to include the effects of diffraction efficiency, transducer efficiency, irradiance profiles of incident laser illumination, aperture size of the Bragg cell, and the acoustic attenuation experienced by the acoustic wavetrain generated by the input r-f signal. A FORTRAN program is developed to model the AOSA and predict the output image plane intensity profiles. A second version of the program includes a time variable permitting dynamic simulation of the system response.

  2. Superfine resolution acoustooptic spectrum analysis

    NASA Technical Reports Server (NTRS)

    Ansari, Homayoon; Lesh, James R.

    1991-01-01

    High resolution spectrum analysis of RF signals is required in applications such as the search for extraterrestrial intelligence, RF interference monitoring, or general purpose decomposition of signals. Sub-Hertz resolution in three-dimensional acoustooptic spectrum analysis is theoretically and experimentally demonstrated. The operation of a two-dimensional acoustooptic spectrum analyzer is extended to include time integration over a sequence of CCD frames.

  3. Gamma spectrum following neutron capture in {sup 167}Er

    SciTech Connect

    Visser, D.; Khoo, T.L.; Lister, C.J.

    1995-08-01

    Statistical decay from a highly excited state samples all the lower-lying states and, hence, provides a sensitive measure of the level density. Pairing has a major impact on the level density, e.g. creating a pair gap between the 0- and 2-quasiparticle configurations. Hence the shape of the statistical spectrum contains information on pairing, and can be used to provide information on the reduction of pairing with thermal excitation energy. For this reason, we measured the complete spectrum of {gamma}rays following thermal neutron capture in {sup 167}Er. The experiment was performed at the Brookhaven reactor using Compton-suppressed Ge detectors from TESSA. The spectrum, which was corrected for detector response and efficiency, reveals primary (first-step, high-energy) transitions up to nearly 8 MeV, secondary (last-step, lower-energy) transitions, as we as a continuous statistical component. Effort was expanded to identify all lines from contaminant sources and an upper limit of 5% was tentatively set for their contributions. The spectral shape of the statistical spectrum will be compared with theoretical spectra obtained from a calculation of pairing which accounts for a stepwise reduction of the pair correlations as the number of quasiparticles increases. The primary lines which decay directly to the near-yrast states will also be used to deduce the level densities.

  4. Production spectrum of gamma rays in interstellar space through neutral pion decay

    NASA Technical Reports Server (NTRS)

    Stephens, S. A.; Badhwar, G. D.

    1981-01-01

    A simple representation is obtained of the observed invariant cross section for the production of neutral pions in proton-proton collisions. Using this representation, the differential and integral production spectra of gamma rays in the galaxy are calculated from interactions of cosmic ray nuclei with interstellar gas. It is shown that the uncertainties in deducing interstellar proton spectrum by demodulating the observed spectrum have only a limited effect on the gamma ray spectrum. Also determined is the gamma ray production spectrum through bremsstrahlung process for a typical interstellar electron spectrum derived from the radio spectrum in the galaxy.

  5. The Measurement and Interpretation of the Cosmic Gamma-ray Spectrum Between 0.3 and 27 Mev as Obtained During the Apollo Mission

    NASA Technical Reports Server (NTRS)

    Peterson, L. E.; Trombka, J. I.

    1973-01-01

    An analysis was made of data collected by Apollo 15 on the total cosmic gamma ray background over the 0.3 to 27 MeV range. Sources of interference with respect to the determination of diffused gamma ray spectrum were considered. Attempts were made to correct the measured spectrum for these background effects.

  6. The infrared spectrum of the Be star gamma Cassiopeiae

    NASA Astrophysics Data System (ADS)

    Hony, S.; Waters, L. B. F. M.; Zaal, P. A.; de Koter, A.; Marlborough, J. M.; Millar, C. E.; Trams, N. R.; Morris, P. W.; de Graauw, Th.

    2000-03-01

    We present the 2.4-45 μm ISO-SWS spectrum of the Be star gamma Cas (B0.5 IVe). The spectrum is characterised by a thermal continuum which can be well fit by a power-law Snu ~ nu 0.99 over the entire SWS wavelength range. For an isothermal disc of ionized gas with constant opening angle, this correponds to a density gradient rho (r) ~ r-2.8. We report the detection of the Humphreys (6-infty ) bound-free jump in emission at 3.4 μm. The size of the jump is sensitive to the electron temperature of the gas in the disc, and we find T ~ 9 000 K, i.e. much lower than the stellar effective temperature (25 000-30 000 K). The spectrum is dominated by numerous emission lines, mostly from H I, but also some He I lines are detected. Several spectral features cannot be identified. The line strengths of the H I emission lines do not follow case B recombination line theory. The line strengths and widths suggest that many lines are optically thick and come from an inner, high density region with radius 3-5 R* and temperature above that of the bulk of the disc material. Only the alpha , beta and gamma transitions of the series lines contain a contribution from the outer regions. The level populations deviate significantly from LTE and are highly influenced by the optically thick, local (disc) continuum radiation field. The inner disc may be rotating more rapidly than the stellar photosphere. based on observations obtained with ISO, an ESA project with instruments funded by ESA Member states (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) with the participation of ISAS and NASA

  7. Gamma-ray burst spectrum with decaying magnetic field

    SciTech Connect

    Zhao, Xiaohong; Bai, Jinming; Li, Zhuo; Liu, Xuewen; Zhang, Bin-bin; Mészáros, Peter E-mail: zhuo.li@pku.edu.cn

    2014-01-01

    In the internal shock model for gamma-ray bursts (GRBs), the synchrotron spectrum from the fast cooling electrons in a homogeneous downstream magnetic field (MF) is too soft to produce the low-energy slope of GRB spectra. However, the MF may decay downstream with distance from the shock front. Here we show that the synchrotron spectrum becomes harder if electrons undergo synchrotron and inverse-Compton cooling in a decaying MF. To reconcile this with the typical GRB spectrum with low-energy slope νF {sub ν}∝ν, the postshock MF decay time must be comparable to the cooling time of the bulk electrons (corresponding to a MF decaying length typically of ∼10{sup 5} skin depths); that the inverse-Compton cooling should dominate synchrotron cooling after the MF decay time; and/or that the MF decays with comoving time roughly as B∝t {sup –1.5}. An internal shock synchrotron model with a decaying MF can account for the majority of GRBs with low-energy slopes not harder than ν{sup 4/3}.

  8. Bragg crystal polarimeter for the Spectrum-X-Gamma mission

    NASA Technical Reports Server (NTRS)

    Holley, J.; Silver, E.; Ziock, K. P.; Novick, R.; Kaaret, P.; Weisskopf, M.; Elsner, R.; Beeman, J.

    1991-01-01

    A Bragg crystal polarimeter for the focal plane of the SODART telescope on the Spectrum-X-Gamma mission is being designed. A mosaic graphite crystal will be oriented at 45 deg to the optic axis of the telescope, thereby preferentially reflecting those X-rays which satisfy the Bragg condition and have electric vectors that are perpendicular to the plane defined by the incident and reflected photons. The reflected X-rays will be detected by an imaging proportional counter with the image providing direct X-ray aspect information. The crystal will be about 50 microns thick to allow X-rays with energies of 4 keV or greater to be transmitted to a lithium block mounted below the graphite. The lithium is used to measure the polarization of these high energy X-rays by exploiting the polarization dependence of Thomson scattering. The development of thin mosaic graphite crystals is discussed and recent reflectivity, transmission, and uniformity measurements are presented.

  9. Bragg crystal polarimeter for the Spectrum-X-Gamma mission

    SciTech Connect

    Holley, J.; Silver, E.; Ziock, K.P. ); Novick, R.; Kaaret, P. . Columbia Astrophysics Lab.); Weisskopf, M.; Elsner, R. . George C. Marshall Space Flight Center); Beeman, J. )

    1990-08-13

    We are designing a Bragg crystal polarimeter for the focal plane of the SODART telescope on the Spectrum-X-Gamma mission. A mosaic graphite crystal will be oriented at 45{degree} to the optic axis of the telescope, thereby preferentially reflecting those x-rays which satisfy the Bragg condition and have electric vectors that are perpendicular to the plane defined by the incident and reflected photons. The reflected x-rays will be detected by an imaging proportional counter with the image providing direct x-ray aspect information. The crystal will be {approx}50 {mu}m thick to allow x-rays with energies {ge}4 keV to be transmitted to a lithium block mounted below the graphite. The lithium is used to measure the polarization of these high energy x-rays by exploiting the polarization dependence of Thomson scattering. The development of thin mosaic graphite crystals is discussed and recent reflectivity, transmission, and uniformity measurements are presented. 8 refs., 11 figs., 1 tab.

  10. Spectrum analysis in beam diagnostics

    SciTech Connect

    Zhang, S.Y.; Weng, W.T.

    1993-04-23

    In this article, we discuss fundamentals of the spectrum analysis in beam diagnostics, where several important particle motions in a circular accelerator are considered. The properties of the Fourier transform are presented. Then the coasting and the bunched beam motion in both longitudinal and transverse are studied. The discussions are separated for the signal particle, multiple particle, and the Schottky noise cases. To demonstrate the interesting properties of the beam motion spectrum, time domain functions are generated, and then the associated spectra are calculated and plotted. In order to show the whole picture in a single plot, some data have been scaled, therefore they may not be realistic in an accelerator.

  11. Design Spectrum Analysis in NASTRAN

    NASA Technical Reports Server (NTRS)

    Butler, T. G.

    1984-01-01

    The utility of Design Spectrum Analysis is to give a mode by mode characterization of the behavior of a design under a given loading. The theory of design spectrum is discussed after operations are explained. User instructions are taken up here in three parts: Transient Preface, Maximum Envelope Spectrum, and RMS Average Spectrum followed by a Summary Table. A single DMAP ALTER packet will provide for all parts of the design spectrum operations. The starting point for getting a modal break-down of the response to acceleration loading is the Modal Transient rigid format. After eigenvalue extraction, modal vectors need to be isolated in the full set of physical coordinates (P-sized as opposed to the D-sized vectors in RF 12). After integration for transient response the results are scanned over the solution time interval for the peak values and for the times that they occur. A module called SCAN was written to do this job, that organizes these maxima into a diagonal output matrix. The maximum amplifier in each mode is applied to the eigenvector of each mode which then reveals the maximum displacements, stresses, forces and boundary reactions that the structure will experience for a load history, mode by mode. The standard NASTRAN output processors have been modified for this task. It is required that modes be normalized to mass.

  12. Prompt-gamma activation analysis

    SciTech Connect

    Lindstrom, R.M.

    1993-01-01

    A permenent, full-time instrument for prompt-gamma activation analysis is nearing completion as part of the Cold Neutron Research Facility (CNRF). The design of the analytical system has been optimized for high gamma detection efficiency and low background, particularly for hydrogen. Because of the purity of the neutron beam, shielding requirements are modest and the scatter-capture background is low. As a result of a compact sample-detector geometry, the sensitivity (counting rate per gram of analyte) is a factor of four better than the existing Maryland-NIST thermal-neutron instrument at the reactor. Hydrogen backgrounds of a few micrograms have already been achieved, which promises to be of value in numerous applications where quantitative nondestructive analysis of small quantities of hydrogen in materials is necessary.

  13. Muon spectrum in air showers initiated by gamma rays

    NASA Technical Reports Server (NTRS)

    Stephens, S. A.; Streitmatter, R. E.

    1985-01-01

    An analytic representation for the invariant cross-section for the production of charged pions in gamma P interactions was derived by using the available cross-sections. Using this the abundance of muons in a gamma ray initiated air shower is calculated.

  14. Towards an amplitude analysis of exclusive. gamma gamma. processes

    SciTech Connect

    Pennington, M.R.

    1988-06-01

    The potential of two photon processes to shed light on the parton content of resonances, we maintain, can only be realized in practice by moving towards an Amplitude Analysis of experimental data. By using the process ..gamma gamma.. ..-->.. ..pi pi.. as an example, the way to do this is discussed. Presently claimed uncertainties in the ..gamma gamma.. width of even the well-known f/sub 2/ (1270) are shown to be over-optimistic and the fitted couplings of the overlapping scalar states in the 1 GeV region meaningless. Only the use of Amplitude Analysis techniques on the new higher statistics data from SLAC and DESY can resolve these uncertainties and lead to definite and significant results. 37 refs., 18 figs.

  15. Planetary gamma-ray spectroscopy: the effects of hydrogen absorption cross-section of the gamma-ray spectrum

    SciTech Connect

    Lapides, J.R.

    1981-01-01

    The gamma-ray spectroscopy of planet surfaces is one of several possible methods that are useful in determining the elemental composition of planet surfaces from orbiting spacecraft. This has been demonstrated on the Apollos 15 and 16 missions as well as the Soviet Mars-5 mission. Planetary gamma-ray emission is primarily the result of natural radioactive decay and cosmic-ray and solar-flare-induced nuclear reactions. Secondary neutron reactions play a large role in the more intense gamma-ray emission. The technique provides information on the elemental composition of the top few tens of centimeters of the planet surface. Varying concentrations of hydrogen and compositional variations that alter the macroscopic thermal-neutron absorption cross section have a significant effect on the neutron flux in the planet surface and therefore also on the gamma-ray emission from the surface. These effects have been systematically studied for a wide range of possible planetary compositions that include Mercury, the moon, Mars, the comets, and the asteroids. The problem of the Martian atmosphere was also investigated. The results of these calculations, in which both surface neutron fluxes and gamma-ray emission fluxes were determined, were used to develop general procedures for obtaining planet compositions from the gamma-ray spectrum. Several changes have been suggested for reanalyzing the Apollos 15 and 16 gamma-ray results. In addition, procedures have been suggested that can be applied to neutron-gamma techniques in mineral and oil exploration.

  16. Local electron spectrum above 100 MeV derived from gamma-ray emissivity spectra

    NASA Technical Reports Server (NTRS)

    Strong, A. W.

    1985-01-01

    Two new determinations of the local gamma-ray emmissivity spectrum are in good accord and were used to derive constraints on the local electron spectrum. The requirement for an electron intensity above 1 GeV larger than previously believed is confirmed and no low energy upturn is then needed.

  17. The VHE gamma-ray spectra of several hard-spectrum blazars from long-term observations with the VERITAS telescope array

    NASA Astrophysics Data System (ADS)

    Madhavan, Arun

    2013-08-01

    Analysis is presented on VERITAS observations of the very high energy gamma-ray spectra of five high frequency peaked BL Lac objects over a range of redshifts. Each object has an unusually hard intrinsic GeV spectrum, and is expected to produce TeV gamma-ray emission into the optically- thick regime of the universe's diffuse extragalactic background light (EBL). Hard spectrum HBLs have recently emerged as an effective tool for measurement of the EBL spectrum, due to extinction of gamma-ray signals from blazars via the pair production interaction gamma-TeVgamma EBL → e+e -. The VERITAS collaboration has approved long term observations on several of these sources, with the specific intent of studying their spectra to probe for absorption features resulting from these interactions. An introduction to the field of particle astrophysics is presented, followed by an overview of the EBL and its relation to the evolution of the universe. The VERITAS gamma-ray telescope is described in detail, followed by a full overview of the analysis techniques used to derive gamma-ray spectra from VERITAS data. The analyses of the blazars themselves are presented, followed by a discussion of their application to further constraints of the EBL. Each blazar is de-absorbed with an assumed EBL spectrum. In each case the intrinsic TeV spectrum is consistent with lower-energy gamma-ray emission in the optically-thin regime of the EBL.

  18. Fermi-LAT detection of hard spectrum gamma-ray activity from the FSRQ PKS 1532+01

    NASA Astrophysics Data System (ADS)

    Ciprini, S.; Cheung, C. C.

    2015-03-01

    The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed increasing gamma-ray flux and an unusually hard gamma-ray spectrum from a source positionally consistent with the flat spectrum radio quasar (FSRQ) PKS 1532+01 (also known as 3FGL J1534.5+0128, Acero et al.

  19. Fermi large area telescope detection of a break in the gamma-ray spectrum of the supernova remnant Cassiopeia A

    SciTech Connect

    Yuan, Yajie; Funk, Stefan; Lande, Joshua; Tibaldo, Luigi; Jóhannesson, Gülauger; Uchiyama, Yasunobu E-mail: funk@slac.stanford.edu E-mail: uchiyama@slac.stanford.edu

    2013-12-20

    We report on observations of the supernova remnant Cassiopeia A in the energy range from 100 MeV to 100 GeV using 44 months of observations from the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope. We perform a detailed spectral analysis of this source and report on a low-energy break in the spectrum at 1.72{sub −0.89}{sup +1.35} GeV. By comparing the results with models for the gamma-ray emission, we find that hadronic emission is preferred for the GeV energy range.

  20. On the bizarre gamma-ray spectrum of SS 433

    NASA Technical Reports Server (NTRS)

    Helfer, H. L.; Savedoff, M. P.

    1984-01-01

    Lamb et al. (1983) have announced the discovery of a pair of gamma-ray lines interpretable as emission of the 1.368 MeV line of Mg-24 in the two oppositely directed relativistic jets of SS 433. The mass loss rate related to the Mg-24 and the kinetic energy flux of the Mg-24 are considered. In the present investigation, it is shown that the mass loss flux must be well in excess of 0.00001 solar mass per yr, while the abundance of the gamma-emitting nucleus is extremely high. Attention is given to the calculation of the gamma-ray production efficiency factor, the size of the emitting region, reaction processes, and X-ray luminosity. It is concluded that for plasma beam models, there must be a substantial overabundance, by a factor of 100 to approximately 1000, of the gamma-line producing nucleus. The association of the gamma-ray lines with Mg-24 is reasonable but not secure.

  1. Plutonium Isotopic Gamma-Ray Analysis

    1992-01-08

    The MGA8 (Multiple Group Analysis) program determines the relative abundances of plutonium and other actinide isotopes in different materials. The program analyzes spectra taken of such samples using a 4096-channel germanium (Ge) gamma-ray spectrometer. The code can be run in a one or two detector mode. The first spectrum, which is required and must be taken at a gain of 0.075 Kev/channel with a high resolution planar detector, contains the 0-300 Kev energy region. Themore » second spectrum, which is optional, must be taken at a gain of 0.25 Kev/channel; it becomes important when analyzing high burnup samples (concentration of Pu241 greater than one percent). Isotopic analysis precisions of one percent or better can be obtained, and no calibrations are required. The system also measures the abundances of U235, U238, Np237, and Am241. A special calibration option is available to perform a one-time peak-shape characterization when first using a new detector system.« less

  2. Energy spectrum of extragalactic gamma-ray sources

    NASA Technical Reports Server (NTRS)

    Protheroe, R. J.

    1985-01-01

    The result of Monte Carlo electron photon cascade calculations for propagation of gamma rays through regions of extragalactic space containing no magnetic field are given. These calculations then provide upper limits to the expected flux from extragalactic sources. Since gamma rays in the 10 to the 14th power eV to 10 to the 17th power eV energy range are of interest, interactions of electrons and photons with the 3 K microwave background radiation are considered. To obtain an upper limit to the expected gamma ray flux from sources, the intergalactic field is assumed to be so low that it can be ignored. Interactions with photons of the near-infrared background radiation are not considered here although these will have important implications for gamma rays below 10 to the 14th power eV if the near infrared background radiation is universal. Interaction lengths of electrons and photons in the microwave background radiation at a temperature of 2.96 K were calculated and are given.

  3. Vibrational spectrum of gamma-HNIW investigated using terahertz time-domain spectroscopy.

    PubMed

    Guo, Lantao; Hu, Ying; Zhang, Yan; Zhang, Cunlin; Chen, Yunqing; Zhang, X-C

    2006-04-17

    Experimental and theoretical investigations of the vibration spectrum of gamma-Hexanitrohexaazaisowurtzitane in the region of 0.2-2.5 terahertz are presented for the first time. The refraction index, absorption coefficient, and complex dielectric function of this sample are measured by terahertz time-domain spectroscopy. The simulated spectrum using density functional theory (DFT) is in agreement with the experimental data. The observed spectra features are assigned based on DFT calculation.

  4. Impaired prefrontal gamma band synchrony in autism spectrum disorders during gaze cueing.

    PubMed

    Richard, Annette E; Lajiness-O'Neill, Renee R; Bowyer, Susan M

    2013-11-13

    Orienting to eye gaze is a vital social skill that is absent or developmentally delayed in autism spectrum disorders (ASD). Neural synchrony in the gamma frequency band is believed to be involved in perceptual and cognitive functions such as eye-gaze processing, and has been found to be abnormal in ASD. The current study used magnetoencephalography to measure neural synchrony in the gamma frequency band in neurotypicals (n=8) and individuals with ASD (n=10) while performing a directional eye-gaze processing task. Results support impaired generation of neural synchrony in the gamma frequency band during eye-gaze processing in ASD. Impaired gamma oscillatory activity in the prefrontal cortex may be associated with impairments in social cognitive functions such as eye-gaze processing in ASD.

  5. The ultraviolet spectrum of noncoronal late-type stars - The Gamma Crucis (M3.4 III) reference spectrum

    NASA Technical Reports Server (NTRS)

    Carpenter, Kenneth G.; Pesce, Joseph E.; Stencel, Robert E.; Brown, Alexander; Johansson, Sveneric

    1988-01-01

    A guide is presented to the UV spectrum of M-type giants and supergiants whose outer atmospheres contain warm chromospheres but not coronae. The M3 giant Gamma Crucis is taken as the archetype of the cooler, oxygen-rich, noncoronal stars. Line identifications and integrated line flux measurements of the chromospheric emission features seen in the 1200-3200 A range of IUE high-resolution spectra are presented. The major fluorescence processes operating in the outer atmosphere of Gamma Crucis, including eight previously unknown pumping processes and 21 new fluorescent line products, are summarized, and the enhancements of selected line strengths by 'line leakage' is discussed. A set of absorption features toward the longer wavelength end of this range is identified which can be used to characterize the radial velocity of the stellar photospheres. The applicability of the results to the spectra of noncoronal stars with different effective temperatures and gravities is discussed.

  6. Simulation of energy absorption spectrum in NaI crystal detector for multiple gamma energy using Monte Carlo method

    SciTech Connect

    Wirawan, Rahadi; Waris, Abdul; Djamal, Mitra; Handayani, Gunawan

    2015-04-16

    The spectrum of gamma energy absorption in the NaI crystal (scintillation detector) is the interaction result of gamma photon with NaI crystal, and it’s associated with the photon gamma energy incoming to the detector. Through a simulation approach, we can perform an early observation of gamma energy absorption spectrum in a scintillator crystal detector (NaI) before the experiment conducted. In this paper, we present a simulation model result of gamma energy absorption spectrum for energy 100-700 keV (i.e. 297 keV, 400 keV and 662 keV). This simulation developed based on the concept of photon beam point source distribution and photon cross section interaction with the Monte Carlo method. Our computational code has been successfully predicting the multiple energy peaks absorption spectrum, which derived from multiple photon energy sources.

  7. An Overview of the XGAM Code and Related Software for Gamma-ray Analysis

    SciTech Connect

    Younes, W.

    2014-11-13

    The XGAM spectrum-fitting code and associated software were developed specifically to analyze the complex gamma-ray spectra that can result from neutron-induced reactions. The XGAM code is designed to fit a spectrum over the entire available gamma-ray energy range as a single entity, in contrast to the more traditional piecewise approaches. This global-fit philosophy enforces background continuity as well as consistency between local and global behavior throughout the spectrum, and in a natural way. This report presents XGAM and the suite of programs built around it with an emphasis on how they fit into an overall analysis methodology for complex gamma-ray data. An application to the analysis of time-dependent delayed gamma-ray yields from 235U fission is shown in order to showcase the codes and how they interact.

  8. MOXE: An X-ray all-sky monitor for Soviet Spectrum-X-Gamma Mission

    NASA Technical Reports Server (NTRS)

    Priedhorsky, W.; Fenimore, E. E.; Moss, C. E.; Kelley, R. L.; Holt, S. S.

    1989-01-01

    A Monitoring Monitoring X-Ray Equipment (MOXE) is being developed for the Soviet Spectrum-X-Gamma Mission. MOXE is an X-ray all-sky monitor based on array of pinhole cameras, to be provided via a collaboration between Goddard Space Flight Center and Los Alamos National Laboratory. The objectives are to alert other observers on Spectrum-X-Gamma and other platforms of interesting transient activity, and to synoptically monitor the X-ray sky and study long-term changes in X-ray binaries. MOXE will be sensitive to sources as faint as 2 milliCrab (5 sigma) in 1 day, and cover the 2 to 20 KeV band.

  9. The Cosmic Rays and Gamma-Quanta Local Sources Spectra Distinction and Formation of Uniform Cosmic Ray Spectrum

    NASA Astrophysics Data System (ADS)

    Georgievna Sinitysna, Vera; Nikolsky, S. I.

    2003-07-01

    The obtained experimental data about local sources of gamma-quanta are characteristic by the following fact. Though the observed metagalactic sources (active galactic nuclei) are 106 - 107 times more powerful, unlike the galactic one, the gamma-quanta energy spectra from both galactic and metagalactic sources can be averaged with spectrum index F (> Eγ ) ˜ Eγ 1.3±0.15 . This result puts - under doubt the assumption about the galactic origin of observable cosmic ray flux. Uniform cosmic ray spectrum is forming in "infinite" number of elastic (or inelastic) collisions with relict photons in intergalactic space, where the cosmic rays are 0.999... part of their time as the common volume of extragalactic space exceeds more then thousand times the total galactic volume in Universe. Accordingly, the observable spectrum distribution has index of (2.72 ± 0.02) = 2.718..., that is Napier's number. The local sources of extra-high energy cosmic radiation search by the EAS flux excess at narrow angular interval at the direction on supposed sources did not give conformable results because of extremely low flux of showers generated by gamma-quanta, which is connected with the process of accumulation of charged particles in Metagalaxy, which includes intergalactic space. This was confirmed at experiments in the ionization calorimeter with Pb absorb ent of total EAS formed by gamma-quanta which have no muons and hadrons flux determination. The analysis of such showers showed that between EAS on observation level of 3760 m high above sea level the "no hadron" showers flux is slight 0.005 ± 0.001 of full EAS flux; "no muons" showers showed the same result at 0.004 ± 0.001 EAS with primary energy > (3 - 4)1014 eV not a single muon was observed (Fig. 1). As a consequence of small flux of EAS containing no hadrons and muons searching of high-energy gamma-quanta stellar sources it was advisable to concentrate on observations of probable high-energy gamma-quanta sources at narrow

  10. The Angular Power Spectrum of BATSE 3B Gamma-Ray Bursts

    NASA Technical Reports Server (NTRS)

    Tegmark, Max; Hartmann, Dieter H.; Briggs, Michael S.; Meegan, Charles A.

    1996-01-01

    We compute the angular power spectrum C(sub l) from the BATSE 3B catalog of 1122 gamma-ray bursts and find no evidence for clustering on any scale. These constraints bridge the entire range from small scales (which probe source clustering and burst repetition) to the largest scales (which constrain possible anisotropics from the Galactic halo or from nearby cosmological large-scale structures). We develop an analysis technique that takes the angular position errors into account. For specific clustering or repetition models, strong upper limits can be obtained down to scales l approx. equal to 30, corresponding to a couple of degrees on the sky. The minimum-variance burst weighting that we employ is visualized graphically as an all-sky map in which each burst is smeared out by an amount corresponding to its position uncertainty. We also present separate bandpass-filtered sky maps for the quadrupole term and for the multipole ranges l = 3-10 and l = 11-30, so that the fluctuations on different angular scales can be inspected separately for visual features such as localized 'hot spots' or structures aligned with the Galactic plane. These filtered maps reveal no apparent deviations from isotropy.

  11. Compton scattering and the gamma-ray power-law spectrum in Markarian 421

    NASA Technical Reports Server (NTRS)

    Zdziarski, Andrzej A.; Krolik, Julian H.

    1993-01-01

    The nearest BL Lac object, Mrk 421, has a gamma-ray spectrum which is approximately flat in EF-sub E from E less than about 50 MeV to E greater than about 1 TeV. Inverse Compton scattering can explain this smooth spectrum, despite the structure in the Klein-Nishina cross section, if the injected electron distribution function is proportional to gamma exp -2, where gamma is the electron Lorentz factor. When this is the case, the structure imprinted on the steady state electron distribution function by the structure in the Klein-Nishina cross section is almost exactly compensated in the radiated spectrum. Because particle acceleration in strong shocks injects particles with this distribution function, this shape injection function is in fact quite plausible. Other blazars may be explained by the same model if the cutoff below TeV energies observed in other objects is due to pair production on the cosmological IR background, as suggested by Stecker et al. (1992).

  12. The solar gamma ray spectrum between 4 and 8 MeV

    NASA Technical Reports Server (NTRS)

    Ramaty, R.; Kozlovsky, B.; Suri, A. N.

    1976-01-01

    The properties of nuclear gamma ray emission in the 4 to 8 MeV range were evaluated. This emission consists of broad and narrow lines resulting from nuclear reactions of energetic H, He, C and O nuclei with ambient matter. Calculations were compared with observations of the 1972, August 4 flare and show that: (1) essentially all the observed radiation in the 4 to 8 MeV region is to the superposition of broad and narrow lines of nuclear origin with almost no contribution from other mechanisms; (2) the accelerated particles in the energy region from about 10 to 100 MeV/amu have a relatively flat Energy spectrum; (3) the calculated gamma ray spectrum, obtained from an isotropic distribution of accelerated particles, fits the observed spectrum better than the spectrum derived from an anisotropic distribution for which the particles' velocity vectors point towards the photosphere; and (4) it is possible to set a stringent upper limit on the ratio of relativistic electrons to protons in flares, consistent with the small, but finite, electron-to-proton ratio in galactic cosmic rays.

  13. Radioisotope identification method for poorly resolved gamma-ray spectrum of nuclear security concern

    NASA Astrophysics Data System (ADS)

    Ninh, Giang Nguyen; Phongphaeth, Pengvanich; Nares, Chankow; Hao, Quang Nguyen

    2016-01-01

    Gamma-ray signal can be used as a fingerprint for radioisotope identification. In the context of radioactive and nuclear materials security at the border control point, the detection task can present a significant challenge due to various constraints such as the limited measurement time, the shielding conditions, and the noise interference. This study proposes a novel method to identify the signal of one or several radioisotopes from a poorly resolved gamma-ray spectrum. In this method, the noise component in the raw spectrum is reduced by the wavelet decomposition approach, and the removal of the continuum background is performed using the baseline determination algorithm. Finally, the identification of radioisotope is completed using the matrix linear regression method. The proposed method has been verified by experiments using the poorly resolved gamma-ray signals from various scenarios including single source, mixing of natural uranium with five of the most common industrial radioactive sources (57Co, 60Co, 133Ba, 137Cs, and 241Am). The preliminary results show that the proposed algorithm is comparable with the commercial method.

  14. A US Coordination Facility for the Spectrum-X-Gamma Observatory

    NASA Technical Reports Server (NTRS)

    Forman, William R.

    1999-01-01

    Spectrum-X Gamma (SXG) is a world-class, orbiting astronomical observatory, with capabilities for all-sky monitoring, polarimetry, and high resolution spectroscopy, and wavelength coverage extending from the ultraviolet (TAUVEX and FUVITA), through the x-ray (SODART and JET-X), to the hard x-ray (MART), and gamma-ray (SPIN) regimes. SXG is a multi-national mission developed under the sponsorship of the Russian Academy of Sciences, with participation from several European countries and the U.S. The U.S. involvement in SXG includes both instrumentation and data rights. The U.S. Spectrum X Gamma Coordination Facility (SXGCF) supports U.S. observers in proposing for SXG SODART observations, analyzing SXG data, and conducting archival research. The SXGCF also has the responsibility for organizing the U.S. archive of SXG data, which will eventually include approximately half of the data from most SXG instruments. This report summarizes the activities of the SXGCF scientific and technical staff during the period from Feb. 1 through July 31, 1999.

  15. COMPUTER ANALYSIS OF PLANAR GAMMA CAMERA IMAGES

    EPA Science Inventory



    COMPUTER ANALYSIS OF PLANAR GAMMA CAMERA IMAGES

    T Martonen1 and J Schroeter2

    1Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, U.S. EPA, Research Triangle Park, NC 27711 USA and 2Curriculum in Toxicology, Unive...

  16. Diffuse gamma radiation. [intensity, energy spectrum and spatial distribution from SAS 2 observations

    NASA Technical Reports Server (NTRS)

    Fichtel, C. E.; Simpson, G. A.; Thompson, D. J.

    1978-01-01

    Results are reported for an investigation of the intensity, energy spectrum, and spatial distribution of the diffuse gamma radiation detected by SAS 2 away from the galactic plane in the energy range above 35 MeV. The gamma-ray data are compared with relevant data obtained at other wavelengths, including 21-cm emission, radio continuum radiation, and the limited UV and radio information on local molecular hydrogen. It is found that there are two quite distinct components to the diffuse radiation, one of which shows a good correlation with the galactic matter distribution and continuum radiation, while the other has a much steeper energy spectrum and appears to be isotropic at least on a coarse scale. The galactic component is interpreted in terms of its implications for both local and more distant regions of the Galaxy. The apparently isotropic radiation is discussed partly with regard to the constraints placed on possible models by the steep energy spectrum, the observed intensity, and an upper limit on the anisotropy.

  17. Fermi-LAT detection of hard spectrum gamma-ray flare from FSRQ S4 1800+44

    NASA Astrophysics Data System (ADS)

    Gasparrini, D.; Buson, S.

    2016-03-01

    The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed increasing gamma-ray flux and an unusually hard gamma-ray spectrum from a source positionally consistent with the flat spectrum radio quasar (FSRQ) S4 1800+44 (also known as 3FGL J1801.5+4403, Acero et al. 2015, ApJS, 218, 23) with radio counterpart coordinates (J2000.0), R.A. = 270.3846454 deg, Dec. = 44.0727500 deg (Johnston et al. 1995, AJ, 110, 880).

  18. Measuring the activity of a {sup 51}Cr neutrino source based on the gamma-radiation spectrum

    SciTech Connect

    Gorbachev, V. V. Gavrin, V. N.; Ibragimova, T. V.; Kalikhov, A. V.; Malyshkin, Yu. M.; Shikhin, A. A.

    2015-12-15

    A technique for the measurement of activities of intense β sources by measuring the continuous gamma-radiation (internal bremsstrahlung) spectra is developed. A method for reconstructing the spectrum recorded by a germanium semiconductor detector is described. A method for the absolute measurement of the internal bremsstrahlung spectrum of {sup 51}Cr is presented.

  19. Exclusive Measurements of the b to s gamma Transition Rate and Photon Energy Spectrum

    SciTech Connect

    Lees, J.P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Brown, David Nathan; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Koch, H.; Schroeder, T.; Asgeirsson, D.J.; Hearty, C.; Mattison, T.S.; McKenna, J.A.; Khan, A.; Blinov, V.E.; Buzykaev, A.R.; /more authors..

    2012-08-30

    We use 429 fb{sup -1} of e{sup +}e{sup -} collision data collected at the {Upsilon}(4S) resonance with the BABAR detector to measure the radiative transition rate of b {yields} s{gamma} with a sum of 38 exclusive final states. The inclusive branching fraction with a minimum photon energy of 1.9 GeV is found to be {Beta}({bar B} {yields} Xs{gamma}) = (3.29 {+-} 0.19 {+-} 0.48) x 10{sup -4} where the first uncertainty is statistical and the second is systematic. We also measure the first and second moments of the photon energy spectrum and extract the best fit values for the heavy-quark parameters, m{sub b} and {mu}{sub {pi}}{sup 2}, in the kinetic and shape function models.

  20. The Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived From First-Year Fermi Large Area Telescope Data

    SciTech Connect

    Abdo, A. A.

    2011-08-19

    We report on the first Fermi Large Area Telescope (LAT) measurements of the so-called 'extra-galactic' diffuse {gamma}-ray emission (EGB). This component of the diffuse {gamma}-ray emission is generally considered to have an isotropic or nearly isotropic distribution on the sky with diverse contributions discussed in the literature. The derivation of the EGB is based on detailed modelling of the bright foreground diffuse Galactic {gamma}-ray emission (DGE), the detected LAT sources and the solar {gamma}-ray emission. We find the spectrum of the EGB is consistent with a power law with differential spectral index {gamma} = 2.41 {+-} 0.05 and intensity, I(> 100 MeV) = (1.03 {+-} 0.17) x 10{sup -5} cm{sup -2} s{sup -1} sr{sup -1}, where the error is systematics dominated. Our EGB spectrum is featureless, less intense, and softer than that derived from EGRET data.

  1. THE {gamma}-RAY SPECTRUM OF GEMINGA AND THE INVERSE COMPTON MODEL OF PULSAR HIGH-ENERGY EMISSION

    SciTech Connect

    Lyutikov, Maxim

    2012-09-20

    We reanalyze the Fermi spectra of the Geminga and Vela pulsars. We find that the spectrum of Geminga above the break is well approximated by a simple power law without the exponential cutoff, making Geminga's spectrum similar to that of Crab. Vela's broadband {gamma}-ray spectrum is equally well fit with both the exponential cutoff and the double power-law shapes. In the broadband double power-law fits, for a typical Fermi spectrum of a bright {gamma}-ray pulsar, most of the errors accumulate due to the arbitrary parameterization of the spectral roll-off. In addition, a power law with an exponential cutoff gives an acceptable fit for the underlying double power-law spectrum for a very broad range of parameters, making such fitting procedures insensitive to the underlying Fermi photon spectrum. Our results have important implications for the mechanism of pulsar high-energy emission. A number of observed properties of {gamma}-ray pulsars-i.e., the broken power-law spectra without exponential cutoffs and stretching in the case of Crab beyond the maximal curvature limit, spectral breaks close to or exceeding the maximal breaks due to curvature emission, patterns of the relative intensities of the leading and trailing pulses in the Crab repeated in the X-ray and {gamma}-ray regions, presence of profile peaks at lower energies aligned with {gamma}-ray peaks-all point to the inverse Compton origin of the high-energy emission from majority of pulsars.

  2. Development and Calibration of the ART-XC Mirror Modules for the Spectrum Rontgen Gamma Mission

    NASA Technical Reports Server (NTRS)

    Ramsey, B.; Gubarev, M.; Elsner, R.; Kolodziejczak, J.; Odell, S.; Swartz, D.; Pavlinsky, M.; Tkachenko, A.; Lapshov, I.

    2013-01-01

    The Spectrum-Röntgen-Gamma (SRG) mission is a Russian-lead X-ray astrophysical observatory that carries two co-aligned X-ray telescope systems. The primary instrument is the German-led extended ROentgen Survey with an Imaging Telescope Array (eROSITA), a 7-module X-ray telescope system that covers the energy range from 0.2-12 keV. The complementary instrument is the Astronomical Roentgen Telescope -- X-ray Concentrator (ART-XC or ART), a 7-module Xray telescope system that provides higher energy coverage, up to 30 keV.

  3. Absorption spectrum of NO in the {gamma}(O, O) band

    SciTech Connect

    Zobnin, A.V.; Korotkov, A.N.

    1995-05-01

    A promising technique for determining the concentration of nitrogen oxide in the air of an industrial zone and in process gases is the measurement of the absorption of UV radiation by this molecule in the {gamma}(O,O) band with the center of {lambda}{sub 0} = 226.5 nm. This band corresponds to the transition X{sup 2}{Pi}{yields}{Alpha}{sup 2}{Sigma} of the NO molecule and is characterized by a complex rotational structure consisting of about 400 lines. This structure cannot be resolved completely by most spectral instruments. However, if the width of the spread function of the device is perceptibly smaller than the width of the given absorption band ({approx_equal}2 nm), but larger than the characteristic space between rotational lines ({approx_equal}0.02 nm), then the recorded transmission spectra of NO are almost insensitive to a change in the form of this function. In the given case, to describe the transmission spectrum it is possible to use the absorption coefficient averaged over rotational lines. And even though the Bouger-Lambert-Beer law is not strictly applicable for this spectrum, the dependence of the transmission spectrum of NO on the optical thickness, temperature, and pressure of the broadening gas can be represented in the form of an empirical dependence that can be useful in practice, for example, when processing the absorption spectra recorded by dispersion gas analyzers. Thus, the need for complex and laborious calculations is avoided, and this simplifies considerably the instrumental implementation of this method of measuring the concentration of NO. The object of the present work is to determine the empirical dependence of the absorption spectrum of NO in the {gamma}(O, O) band on the optical thickness, temperature, and pressure of the broadening gas in the ranges most frequently encountered in operation of dispersion gas analyzers.

  4. Superior orientation discrimination and increased peak gamma frequency in autism spectrum conditions.

    PubMed

    Dickinson, Abigail; Bruyns-Haylett, Michael; Smith, Richard; Jones, Myles; Milne, Elizabeth

    2016-04-01

    While perception is recognized as being atypical in individuals with autism spectrum conditions (ASC), the underlying mechanisms for such atypicality are unclear. Here we test the hypothesis that individuals with ASC will show enhanced orientation discrimination compared with neurotypical observers. This prediction is based both on anecdotal report of superior discriminatory skills in ASC and also on evidence in the auditory domain that some individuals with ASC have superior pitch discrimination. In order to establish whether atypical perception might be mediated by an imbalance in the ratio of neural excitation and inhibition (E:I ratio), we also measured peak gamma frequency, which provides an indication of neural inhibition levels. Using a rigorous thresholding method, we found that orientation discrimination thresholds for obliquely oriented stimuli were significantly lower in participants with ASC. Using EEG to measure the visually induced gamma band response, we also found that peak gamma frequency was higher in participants with ASC, relative to a well-matched control group. These novel results suggest that neural inhibition may be increased in the occipital cortex of individuals with ASC. Implications for existing theories of an imbalance in the E:I ratio of ASC are discussed. PMID:27043918

  5. The optical-ultraviolet-gamma-ray spectrum of 3C 279

    NASA Technical Reports Server (NTRS)

    Netzer, Hagai; Kazanas, D.; Wills, Beverly J.; Wills, D.; Mingsheng, Han; Brotherton, M. S.; Baldwin, J. A.; Ferkand, G. J.; Browne, I. W. A.

    1994-01-01

    We have obtained spectrosocpy of the violently variable quasar 3C 279, simultaneous with gamma-ray observations, in 1992 April. Our combined optical (McDonald Observatory and Cerro Tololo InterAmerican Observatory (CTIO) and ultraviolet (HST) observations, made when the source was faint, show a very steep power-law continuum (F(sub nu) is proportional to nu(exp -1.95), and strong broad emission lines. This is the first time that the broad ultraviolet lines of this object have been measured, and we note several unusual properties of the spectrum. In particular, the profiles of C IV lambda 1549 and Mg II lambda 2798 are asymmetric, with very strong red wings, in contrast to the symmetic profiles of Ly alpha C III lambda 1909, and possible H-beta. The observed asymmetry cannot be explained by a simple outflow associted with the eruption of the source. In addition, the C IV lambda 1549/Ly-alpha and C III lambda 1909/Ly-alpha line intensity ratios are the largest we have observed in out Hubble Space Telescope (HST) sample of more than 30 radio-loud quasars, even though the C III llambda 1909/C IV lambda 1549 ratio is quite typical. 3C 279 was observed in the gamma-ray region by EGRET (Energetic Gamma-Ray Experiment Telescope) at the same time as our optical-ultraviolet observations. The extrapolated ultraviolet continuum falls nine orders of magnitude below the gamma-ray point and we show that this, combined with the optical UV continuum slope, is enough to rule out several synchtoyotron-self-Compton models suggested to explain the multiwavelength spectra of blazars.

  6. RADSAT Benchmarks for Prompt Gamma Neutron Activation Analysis Measurements

    SciTech Connect

    Burns, Kimberly A.; Gesh, Christopher J.

    2011-07-01

    The accurate and efficient simulation of coupled neutron-photon problems is necessary for several important radiation detection applications. Examples include the detection of nuclear threats concealed in cargo containers and prompt gamma neutron activation analysis for nondestructive determination of elemental composition of unknown samples. High-resolution gamma-ray spectrometers are used in these applications to measure the spectrum of the emitted photon flux, which consists of both continuum and characteristic gamma rays with discrete energies. Monte Carlo transport is the most commonly used simulation tool for this type of problem, but computational times can be prohibitively long. This work explores the use of multi-group deterministic methods for the simulation of coupled neutron-photon problems. The main purpose of this work is to benchmark several problems modeled with RADSAT and MCNP to experimental data. Additionally, the cross section libraries for RADSAT are updated to include ENDF/B-VII cross sections. Preliminary findings show promising results when compared to MCNP and experimental data, but also areas where additional inquiry and testing are needed. The potential benefits and shortcomings of the multi-group-based approach are discussed in terms of accuracy and computational efficiency.

  7. Derivative based sensitivity analysis of gamma index.

    PubMed

    Sarkar, Biplab; Pradhan, Anirudh; Ganesh, T

    2015-01-01

    Originally developed as a tool for patient-specific quality assurance in advanced treatment delivery methods to compare between measured and calculated dose distributions, the gamma index (γ) concept was later extended to compare between any two dose distributions. It takes into effect both the dose difference (DD) and distance-to-agreement (DTA) measurements in the comparison. Its strength lies in its capability to give a quantitative value for the analysis, unlike other methods. For every point on the reference curve, if there is at least one point in the evaluated curve that satisfies the pass criteria (e.g., δDD = 1%, δDTA = 1 mm), the point is included in the quantitative score as "pass." Gamma analysis does not account for the gradient of the evaluated curve - it looks at only the minimum gamma value, and if it is <1, then the point passes, no matter what the gradient of evaluated curve is. In this work, an attempt has been made to present a derivative-based method for the identification of dose gradient. A mathematically derived reference profile (RP) representing the penumbral region of 6 MV 10 cm × 10 cm field was generated from an error function. A general test profile (GTP) was created from this RP by introducing 1 mm distance error and 1% dose error at each point. This was considered as the first of the two evaluated curves. By its nature, this curve is a smooth curve and would satisfy the pass criteria for all points in it. The second evaluated profile was generated as a sawtooth test profile (STTP) which again would satisfy the pass criteria for every point on the RP. However, being a sawtooth curve, it is not a smooth one and would be obviously poor when compared with the smooth profile. Considering the smooth GTP as an acceptable profile when it passed the gamma pass criteria (1% DD and 1 mm DTA) against the RP, the first and second order derivatives of the DDs (δD', δD") between these two curves were derived and used as the boundary values

  8. Gamma-ray Background Spectrum and Annihilation Rate in the Baryon-symmetric Big-bang Cosmology

    NASA Technical Reports Server (NTRS)

    Puget, J. L.

    1973-01-01

    An attempt was made to acquire experimental information on the problem of baryon symmetry on a large cosmological scale by observing the annihilation products. Data cover absorption cross sections and background radiation due to other sources for the two main products of annihilation, gamma rays and neutrinos. Test results show that the best direct experimental test for the presence of large scale antimatter lies in the gamma ray background spectrum between 1 and 70 MeV.

  9. [Laser Raman spectrum analysis of carbendazim pesticide].

    PubMed

    Wang, Xiao-bin; Wu, Rui-mei; Liu, Mu-hua; Zhang, Lu-ling; Lin, Lei; Yan, Lin-yuan

    2014-06-01

    Raman signal of solid and liquid carbendazim pesticide was collected by laser Raman spectrometer. The acquired Raman spectrum signal of solid carbendazim was preprocessed by wavelet analysis method, and the optimal combination of wavelet denoising parameter was selected through mixed orthogonal test. The results showed that the best effect was got with signal to noise ratio (SNR) being 62.483 when db2 wavelet function was used, decomposition level was 2, the threshold option scheme was 'rigisure' and reset mode was 'sln'. According to the vibration mode of different functional groups, the de-noised Raman bands could be divided into 3 areas: 1 400-2 000, 700-1 400 and 200-700 cm(-1). And the de-noised Raman bands were assigned with and analyzed. The characteristic vibrational modes were gained in different ranges of wavenumbers. Strong Raman signals were observed in the Raman spectrum at 619, 725, 964, 1 022, 1 265, 1 274 and 1 478 cm(-1), respectively. These characteristic vibrational modes are characteristic Raman peaks of solid carbendazim pesticide. Find characteristic Raman peaks at 629, 727, 1 001, 1 219, 1 258 and 1 365 cm(-1) in Raman spectrum signal of liquid carbendazim. These characteristic peaks were basically tallies with the solid carbendazim. The results can provide basis for the rapid screening of pesticide residue in food and agricultural products based on Raman spectrum.

  10. On the performance of the scattering and crystal polarimeters for the Spectrum-X-Gamma mission

    NASA Technical Reports Server (NTRS)

    Elsner, R. F.; Weisskopf, M. C.; Novick, R.; Kaaret, P.; Silver, E.

    1990-01-01

    X-ray scattering from a lithium disk and Bragg reflection from a mosaic graphite crystal can be exploited to measure the linear polarization of radiation emitted from cosmic X-ray sources. The sensitivity is enhanced if the polarimeters are placed at the focus of an X-ray telescope. Such devices form two of the components of the Stellar X-ray Polarimeter experiment scheduled to fly on the Spectrum-X-Gamma mission. The expected on-axis performance of the two components is described based on detailed Monte Carlo simulations. The polarimetry experiment is expected to provide sensitive measurements of linear polarization for many cosmic X-ray sources. The nature and utility of such observations is described for pulsing X-ray sources such as the Crab pulsar and Her X-1.

  11. SXRP - An X-ray polarimeter for the SPECTRUM-X-Gamma mission

    NASA Technical Reports Server (NTRS)

    Costa, E.; Piro, L.; Soffitta, P.; Massaro, E.; Matt, G.; Perola, G. C.; Giarrusso, S.; La Rosa, G.; Manzo, G.; Santangelo, A.

    1992-01-01

    The Stellar X-ray Polarimeter (SXRP) is a focal plane instrument which will be flown on the SPECTRUM-X-Gamma mission in 1993. The polarimeter is composed of two separate instruments: the first exploits the dependence on the polarization of the Bragg reflection from a graphite crystal, and of the Thomson scattering from a metallic lithium target. The second instrument makes use of the recently discovered polarization dependence of X-ray photoemission from CsI. The SXRP will permit sensitive measurements of several classes of galactic X-ray sources, such as X-ray pulsars, black-hole candidates and supernova remnants. Moreover, and for the first time, SXRP will be able to perform highly sensitive measurements of the brightest extragalactic sources.

  12. The Spectrum of Isotropic Diffuse Gamma-Ray Emission Between 100 Mev and 820 Gev

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Albert, A.; Atwood, W. B.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Brandt, T. J.; Hays, E.; Perkins, J. S.

    2014-01-01

    The gamma-ray sky can be decomposed into individually detected sources, diffuse emission attributed to the interactions of Galactic cosmic rays with gas and radiation fields, and a residual all-sky emission component commonly called the isotropic diffuse gamma-ray background (IGRB). The IGRB comprises all extragalactic emissions too faint or too diffuse to be resolved in a given survey, as well as any residual Galactic foregrounds that are approximately isotropic. The first IGRB measurement with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi) used 10 months of sky-survey data and considered an energy range between 200 MeV and 100 GeV. Improvements in event selection and characterization of cosmic-ray backgrounds, better understanding of the diffuse Galactic emission, and a longer data accumulation of 50 months, allow for a refinement and extension of the IGRB measurement with the LAT, now covering the energy range from 100 MeV to 820 GeV. The IGRB spectrum shows a significant high-energy cutoff feature, and can be well described over nearly four decades in energy by a power law with exponential cutoff having a spectral index of 2.32 plus or minus 0.02 and a break energy of (279 plus or minus 52) GeV using our baseline diffuse Galactic emission model. The total intensity attributed to the IGRB is (7.2 plus or minus 0.6) x 10(exp -6) cm(exp -2) s(exp -1) sr(exp -1) above 100 MeV, with an additional +15%/-30% systematic uncertainty due to the Galactic diffuse foregrounds.

  13. Design of new electronic edition of gamma-ray spectrum catalogues for Internet presentation

    SciTech Connect

    Heath, R.L.

    1997-12-31

    New editions of the original Gamma-ray Spectrum Catalogues are being prepared for publication in electronic format. The Catalogues will be available on CD-ROM and as an Internet resource from the INEL. All material is formatted in Adobe Acrobat. Additions to the original content of the Catalogues include integrated decay schemes, and tables of related decay data from the ENSDF file. Spectra representing the response of large-volume Ge detectors, alpha-particle spectra, prompt neutron capture and inelastic scattering gamma-ray spectra, and gross fission product spectra are being developed for future addition. All numerical data are available in relational database format with an advanced graphic user interface (GUI), designed for retreival of both graphics and data for general laboratory use. The major emphasis of the presentation will be on technology applied in the design of material for screen presentation, incorporating color, advanced database technology, and graphics formatting to overcome bandwidth limitations on the internet. The first edition of the Catalogues in CD-ROM format is currently in the beta test phase. The web site content presently available will be described.

  14. Development of Monte Carlo code for coincidence prompt gamma-ray neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Han, Xiaogang

    Prompt Gamma-Ray Neutron Activation Analysis (PGNAA) offers a non-destructive, relatively rapid on-line method for determination of elemental composition of bulk and other samples. However, PGNAA has an inherently large background. These backgrounds are primarily due to the presence of the neutron excitation source. It also includes neutron activation of the detector and the prompt gamma rays from the structure materials of PGNAA devices. These large backgrounds limit the sensitivity and accuracy of PGNAA. Since most of the prompt gamma rays from the same element are emitted in coincidence, a possible approach for further improvement is to change the traditional PGNAA measurement technique and introduce the gamma-gamma coincidence technique. It is well known that the coincidence techniques can eliminate most of the interference backgrounds and improve the signal-to-noise ratio. A new Monte Carlo code, CEARCPG has been developed at CEAR to simulate gamma-gamma coincidence spectra in PGNAA experiment. Compared to the other existing Monte Carlo code CEARPGA I and CEARPGA II, a new algorithm of sampling the prompt gamma rays produced from neutron capture reaction and neutron inelastic scattering reaction, is developed in this work. All the prompt gamma rays are taken into account by using this new algorithm. Before this work, the commonly used method is to interpolate the prompt gamma rays from the pre-calculated gamma-ray table. This technique works fine for the single spectrum. However it limits the capability to simulate the coincidence spectrum. The new algorithm samples the prompt gamma rays from the nucleus excitation scheme. The primary nuclear data library used to sample the prompt gamma rays comes from ENSDF library. Three cases are simulated and the simulated results are benchmarked with experiments. The first case is the prototype for ETI PGNAA application. This case is designed to check the capability of CEARCPG for single spectrum simulation. The second

  15. PIXEF: The Livermore PIXE spectrum analysis package

    SciTech Connect

    Antolak, A.J.; Bench, G.S.

    1993-07-01

    PIXEF (for, PIXE-Fit) is a proton-induced x-ray emission (PIXE) data analysis program designed for analyzing medium to heavy element matrices while retaining the capability to treat lower atomic number targets. Using nonlinear least squares fitting techniques, algorithms have been developed or modified both for fitting the characteristic x-ray peaks and representing the associated bremsstrahung and {gamma}-ray background. Self-absorption and secondary fluorescence are explicitly determined for K shell and L subshell x rays. Data bases have been created or improved, where necessary, from reliable current literature values or by direct measurement for element mass attenuation coefficients, photoionization and proton ionization cross sections, Coster-Kronig transition probabilities, fluorescence yields, and relative line intensities. The utility of the program is demonstrated with PDM spectra obtained at Livermore.

  16. Response Spectrum Analysis of Reinforced Concrete Buildings

    NASA Astrophysics Data System (ADS)

    Chandak, N. R.

    2012-05-01

    In this work, a parametric study on reinforced concrete (RC) structural walls and moment resisting frames building representative of structural types using response spectrum method is carried out. Here, the design spectra recommended by Indian Standard Code [1] and two other well known codes (Uniform Building Code, Euro Code 8) have been considered for comparison. The main objective of this study is to investigate the differences caused by the use of different codes in the dynamic analysis of multistoried RC building. Three different floor plans that are symmetric (SB), monosymmetric (MB), and unsymmetric (UB) with torsional irregularity are taken as sample buildings. To evaluate the seismic response of the buildings, elastic analysis was performed by using response spectrum method using the computer program SAP2000. Periods, base shears, lateral displacement and interstory drift, torque located at code defined ground type are comparatively presented. It is observed from the comparative study that the base shear using IS code is higher in all the three buildings, when compared to that of with other codes.

  17. MOOG: LTE line analysis and spectrum synthesis

    NASA Astrophysics Data System (ADS)

    Sneden, Chris; Bean, Jacob; Ivans, Inese; Lucatello, Sara; Sobeck, Jennifer

    2012-02-01

    MOOG performs a variety of LTE line analysis and spectrum synthesis tasks. The typical use of MOOG is to assist in the determination of the chemical composition of a star. The basic equations of LTE stellar line analysis are followed. The coding is in various subroutines that are called from a few driver routines; these routines are written in standard FORTRAN. The standard MOOG version has been developed on unix, linux and macintosh computers. One of the chief assets of MOOG is its ability to do on-line graphics. The plotting commands are given within the FORTRAN code. MOOG uses the graphics package SM, chosen for its ease of implementation in FORTRAN codes. Plotting calls are concentrated in just a few routines, and it should be possible for users of other graphics packages to substitute other appropriate FORTRAN commands.

  18. Gamma Detector Response and Analysis Software - Light

    2004-06-14

    GADRAS is used to analyze gamma-ray spectra, which may be augmented by neutron count rate information. The fundamental capabilities of GADRAS are imparted by physics-based detector response functions for a variety of gamma ray and neufron detectors. The software has provisions for characterizing detector response parameters so that specta can be computed accurately over the range 30keV key to II MeV. Associated neutron detector count rates can also be computed for characterized detectors. GADRAS incorporatesmore » a variety of analysis algorithms that utilize the computed spectra. The full version of GADRAS incorporates support for computation of radiation leakages from complex source models, but this capability is not supported by GADRAS-LT. GADRAS has been and will continue to be disseminated free of charge to government agencies and National Laboratories as OUO software. GADRAS-LT is a limited software version that was prepared for exclusive use of our Technology Transfer parnter Thermo Electron (TE). TE will use the software to characterize and test radiation detectors that are fabricated under the terms of our partnership. The development of these sensors has been defined as a National Security priority by our sponsor, NNSA/NA-20, by DHS/S&T, and by SNL president Paul Robinson. Although GADRAS-LT is OUO, features that are not essential to the detector development have been removed. TE will not be licensed to commercialize GADRAS-LT or to distribute it to third parties.« less

  19. Analysis of the 237Np-233Pa photon spectrum using the full response function method.

    PubMed

    Shchukin, G; Iakovlev, K; Morel, J

    2004-01-01

    A study has been made of X- and gamma-ray emission from 237Np in equilibrium with 233Pa using the full response function method. This analysis process is characterised by photon spectrometry in which the entire spectrum is modelled in a pseudo-empirical way by means of elementary functions describing the total absorption and escape peaks, the Compton diffusion internal and external to the detector and the peaks resulting from detection of internal conversion electrons. This method has been applied to determine the L X-, K X- and gamma-rays emission probabilities in 237Np and 233Pa decay studies.

  20. Analysis of the 237Np-233Pa photon spectrum using the full response function method.

    PubMed

    Shchukin, G; Iakovlev, K; Morel, J

    2004-01-01

    A study has been made of X- and gamma-ray emission from 237Np in equilibrium with 233Pa using the full response function method. This analysis process is characterised by photon spectrometry in which the entire spectrum is modelled in a pseudo-empirical way by means of elementary functions describing the total absorption and escape peaks, the Compton diffusion internal and external to the detector and the peaks resulting from detection of internal conversion electrons. This method has been applied to determine the L X-, K X- and gamma-rays emission probabilities in 237Np and 233Pa decay studies. PMID:14987650

  1. THE EXTRAGALACTIC BACKGROUND LIGHT FROM THE MEASUREMENTS OF THE ATTENUATION OF HIGH-ENERGY GAMMA-RAY SPECTRUM

    SciTech Connect

    Gong Yan; Cooray, Asantha

    2013-07-20

    The attenuation of high-energy gamma-ray spectrum due to the electron-positron pair production against the extragalactic background light (EBL) provides an indirect method to measure the EBL of the universe. We use the measurements of the absorption features of the gamma-rays from blazars as seen by the Fermi Gamma-ray Space Telescope to explore the EBL flux density and constrain the EBL spectrum, star formation rate density (SFRD), and photon escape fraction from galaxies out to z = 6. Our results are basically consistent with the existing determinations of the quantities. We find a larger photon escape fraction at high redshifts, especially at z = 3, compared to the result from recent Ly{alpha} measurements. Our SFRD result is consistent with the data from both gamma-ray burst and ultraviolet (UV) observations in the 1{sigma} level. However, the average SFRD we obtain at z {approx}> 3 matches the gamma-ray data better than the UV data. Thus our SFRD result at z {approx}> 6 favors the fact that star formation alone is sufficiently high enough to reionize the universe.

  2. A US coordination Facility for the Spectrum-X-Gamma Observatory

    NASA Technical Reports Server (NTRS)

    Forman, W.; West, Donald (Technical Monitor)

    2001-01-01

    We have completed our efforts in support of the Spectrum X Gamma mission under a NASA grant. These activities have included direct support to the mission, developing unifying tools applicable to SXG and other X-ray astronomy missions, and X-ray astronomy research to maintain our understanding of the importance and relevance of SXG to the field. SXG provides: 1) Simultaneous Multiwavelength Capability; 2) Large Field of View High Resolution Imaging Spectroscopy; 3) Sensitive Polarimetry with SXRP (Stellar X-Ray Polarimeter). These capabilities will ensure the fulfillment of the following objectives: understanding the accretion dynamics and the importance of reprocessing, upscattering, and disk viscosity around black holes; studying cluster mergers; spatially resolving cluster cooling flows to detect cooling gas; detecting cool gas in cluster outskirts in absorption; mapping gas in filaments around clusters; finding the 'missing' baryons in the Universe; determining the activity history of the black hole in the Galactic Center of our own central black hole; determining pulsar beam geometry; searching for the Lense-Thirring effect in black hole sources; constraining emission mechanisms and accretion geometry in AGN.

  3. Gamma Detector Response and Analysis Software (GADRAS) v. 16.0

    SciTech Connect

    Mitchell, Dean; & Mattingly, John

    2009-12-24

    GADRAS is a general purpose application for the modeling and analysis of radiation detector responses, primarily gamma spectroscopic instruments and neutron detectors based on proportional counters. It employs radiation source and detector response models to predict the response of user-defined detectors to user-defined sources. It implements methods to identify radiation sources from their measured signatures, primarily the measured gamma spectrum and neutron count rate. Radiation source emissions are calculated using analytical and numerical radiation transport models. Detector responses are calculated using point models of the detector material, dimensions, collimation, and scattering environment. Analytical methods are implemented using linear and nonlinear regression techniques.

  4. Gamma Detector Response and Analysis Software (GADRAS) v. 16.0

    2009-12-24

    GADRAS is a general purpose application for the modeling and analysis of radiation detector responses, primarily gamma spectroscopic instruments and neutron detectors based on proportional counters. It employs radiation source and detector response models to predict the response of user-defined detectors to user-defined sources. It implements methods to identify radiation sources from their measured signatures, primarily the measured gamma spectrum and neutron count rate. Radiation source emissions are calculated using analytical and numerical radiation transportmore » models. Detector responses are calculated using point models of the detector material, dimensions, collimation, and scattering environment. Analytical methods are implemented using linear and nonlinear regression techniques.« less

  5. On the determination of the cosmic infrared background radiation from the high-energy spectrum of extragalactic gamma-ray sources

    NASA Technical Reports Server (NTRS)

    Dwek, Eli; Slavin, Jonathan

    1994-01-01

    In a recent paper Stecker, De Jager, & Salamon have suggested using the observed approximately MeV to TeV spectra of extragalactic gamma-ray sources as probes of the local density of the cosmic infrared background radiation (CIBR) and have subsequently claimed a first possible measurement of the CIBR from the analysis of the gamma-ray spectrum of Mrk 421 (De Jager, Stecker, & Salamon). The CIBR from normal galaxies consists of two components: a stellar emission component (CIBRs), and a thermal dust emission component (CIBRd). Photons with energies in the approximately 0.1-2 TeV range interact primarily with the CIBRs, whereas interactions with CIBRd dominate the absorption of photons in the approximately 2-100 TeV energy range. SDS 92 and DSS94 considered only the interaction of the gamma-rays with the dust emission component of the CIBR. We present here an improved analysis of the absorption of extragalactic TeV gamma rays by the CIBR, taking the dual nature of its origin into account. Applying the analysis to the observed gamma-ray spectrum of Mrk 421, a BL Lac object at z = 0.031, we find agreement with DSS94 tentative evidence for absorption by the CINRs. Our analysis therefore limits the detection of the CIBR to the approximately 15-40 micron wavelength regime which, considering the uncertainties in the highest energy (greater than 4 TeV) data and ion the possibility of absorption inside the source, many turn out to be an upper limit on its energy density. At shorter wavelengths (lambda approximately = 1-15 microns), where the gamma-ray interactions are dominated by the CIBRs, our analysis definitely yields only an upper limit on the energy density of the CIBR. In contrast, DSS94 have claimed a possible first measurement of the CIBR over the entire 1-120 micron wavelength region. The upper limit on the CIBRs and tentative detection of the CIBRd are consistent with normal galaxies contributing most of the energy to the CIBR, and constrain the contribution of

  6. Fermi-LAT Detection of an Unusual Hard Spectrum and Enhanced Gamma-ray Emission from the FSRQ PKS B1035-281

    NASA Astrophysics Data System (ADS)

    Carpenter, Bryce; Ojha, Roopesh

    2016-02-01

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope has observed increasing gamma-ray flux and an unusually hard spectrum from a source positionally consistent with the flat spectrum radio quasar PKS B1035-281 (also known as 3FGL J1037.5-2821, Acero et al. 2015, ApJS, 218, 23) with radio coordinates R.A.: 159.4269058 deg, Dec: -28.3844750 deg (J2000, Beasley et al. 2002, ApJS, 141, 13) at redshift z=1.066 (Shaw et al. 2012, ApJ, 748, 49). Preliminary analysis indicates that on 24 February 2016 this source was in a high-flux state, with a daily averaged gamma-ray flux (E > 100MeV) of (0.7+/-0.1) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only) corresponding to a flux increase of a factor of about 30 over its four-year average flux (3FGL J1037.5-2821).

  7. MOXE - An X-ray all-sky monitor for the Soviet Spectrum-X-Gamma mission

    NASA Technical Reports Server (NTRS)

    Priedhorsky, W.; Fenimore, E. E.; Moss, C. E.; Kelley, R. L.; Holt, S. S.

    1989-01-01

    A Monitoring X-Ray Equipment (MOXE) is being developed for the Soviet Spectrum-X-Gamma Mission. MOXE is an X-ray all-sky monitor based on array of pinhole cameras, to be provided via a collaboration between Goddard Space Flight Center and Los Alamos National Laboratory. The objectives are to alert other observers on Spectrum-X-Gamma and other platforms of interesting transient activity, and to synoptically monitor the X-ray sky and study long-term changes in X-ray binaries. MOXE will be sensitive to source as faint as 2 milliCrab (5 sigma) in 1 day, and cover the 2 to 20 KeV band.

  8. Gamma-ray Spectral Analysis Algorithm Library

    1997-09-25

    The routines of the Gauss Algorithm library are used to implement special purpose products that need to analyze gamma-ray spectra from GE semiconductor detectors as a part of their function. These routines provide the ability to calibrate energy, calibrate peakwidth, search for peaks, search for regions, and fit the spectral data in a given region to locate gamma rays.

  9. Gamma-ray spectral analysis algorithm library

    SciTech Connect

    Egger, A. E.

    2013-05-06

    The routines of the Gauss Algorithms library are used to implement special purpose products that need to analyze gamma-ray spectra from Ge semiconductor detectors as a part of their function. These routines provide the ability to calibrate energy, calibrate peakwidth, search for peaks, search for regions, and fit the spectral data in a given region to locate gamma rays.

  10. Effects of p-wave annihilation on the angular power spectrum of extragalactic gamma-rays from dark matter annihilation

    SciTech Connect

    Campbell, Sheldon; Dutta, Bhaskar

    2011-10-01

    We present a formalism for estimating the angular power spectrum of extragalactic gamma-rays produced by dark matter annihilating with any general velocity-dependent cross section. The relevant density and velocity distribution of dark matter is modeled as an ensemble of smooth, universal, rigid, disjoint, spherical halos with distribution and universal properties constrained by simulation data. We apply this formalism to theories of dark matter with p-wave annihilation, for which the relative-velocity-weighted annihilation cross section is {sigma}v=a+bv{sup 2}. We determine that this significantly increases the gamma-ray power if b/a > or approx. 10{sup 6}. The effect of p-wave annihilation on the angular power spectrum is very similar for the sample of particle physics models we explored, suggesting that the important effect for a given b/a is largely determined by the cosmic dark matter distribution. If the dark matter relic from strong p-wave theories is thermally produced, the intensities of annihilation gamma-rays are strongly p-wave suppressed, making them difficult to observe. If an angular power spectrum consistent with a strong p wave were to be observed, it would likely indicate nonthermal production of dark matter in the early Universe.

  11. The design of a source to simulate the gamma-ray spectrum emitted by a radioisotope thermoelectric generator

    NASA Technical Reports Server (NTRS)

    Reier, M.

    1972-01-01

    A simulated source was designed to duplicate the gamma spectrum of a uniform cylindrical 2200-watt Pu02 radioisotope thermoelectric generator containing 81% Pu-238 and 1.2 ppm Pu-236. Gamma rays from the decay of Pu-238, Am-241, Pu-239, and the 0-18(alpha,n)Ne-21 reaction were catalogued in broad energy groups. Two 46- and one 22-mc Th-228 sources provided simulation at various times in the life of the fuel capsule up to 18 years, which covers the time span of an outer planet mission. Emission from Th-228 represents the overwhelming contribution of the gamma spectrum after the first few years. The sources, in the form of 13-inch rods, were placed in a concentric hole in a cylinder of depleted uranium, which provided shielding equivalent to the self-shielding of the fuel capsule. The thickness of the U-238 cylinder (0.55cm) was determined by Monte Carlo calculations to insure that the spectrum emerging from the simulated source matched that of the fuel capsule.

  12. An Analysis of Spectrum Research on Teaching

    ERIC Educational Resources Information Center

    Chatoupis, Constantine

    2010-01-01

    Spectrum research on teaching has been conducted since 1970s. The purpose of this study was to identify, categorize, and analyze research in this area. Fifty three Spectrum studies conducted between 1970 and 2008 were included in this study. Each paper was coded for (a) decade the study was published, (b) publication outlet/dissertation research,…

  13. Correlation between peak energy and Fourier power density spectrum slope in gamma-ray bursts

    NASA Astrophysics Data System (ADS)

    Dichiara, S.; Guidorzi, C.; Amati, L.; Frontera, F.; Margutti, R.

    2016-05-01

    Context. The origin of the gamma-ray burst (GRB) prompt emission still defies explanation, in spite of recent progress made, for example, on the occasional presence of a thermal component in the spectrum along with the ubiquitous non-thermal component that is modelled with a Band function. The combination of finite duration and aperiodic modulations make GRBs hard to characterise temporally. Although correlations between GRB luminosity and spectral hardness on one side and time variability on the other side have long been known, the loose and often arbitrary definition of the latter makes the interpretation uncertain. Aims: We characterise the temporal variability in an objective way and search for a connection with rest-frame spectral properties for a number of well-observed GRBs. Methods: We studied the individual power density spectra (PDS) of 123 long GRBs with measured redshift, rest-frame peak energy Ep,i of the time-averaged ν Fν spectrum, and well-constrained PDS slope α detected with Swift, Fermi and past spacecraft. The PDS were modelled with a power law either with or without a break adopting a Bayesian Markov chain Monte Carlo technique. Results: We find a highly significant Ep,i-α anti-correlation. The null hypothesis probability is ~10-9. Conclusions: In the framework of the internal shock synchrotron model, the Ep,i-α anti-correlation can hardly be reconciled with the predicted Ep,i ∝ Γ-2, unless either variable microphysical parameters of the shocks or continual electron acceleration are assumed. Alternatively, in the context of models based on magnetic reconnection, the PDS slope and Ep,i are linked to the ejecta magnetisation at the dissipation site, so that more magnetised outflows would produce more variable GRB light curves at short timescales (≲1 s), shallower PDS, and higher values of Ep,i. Full Table 1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc

  14. Singular Spectrum Analysis With Missing Data

    NASA Astrophysics Data System (ADS)

    Kondrashov, D.; Feliks, Y.; Ghil, M.

    2004-12-01

    A Singular Spectrum Analysis (SSA) with gaps of missing data is presented. SSA is a data-adaptive, non-parametric spectral method based on diagonalizing the lag-covariance matrix of a time series. Using leading oscillatory SSA modes, we iteratively produce estimates of missing data, which are then used to compute a self-consistent lag-covariance matrix. For a univariate record, SSA imputation utilizes only temporal correlations in the data to fill up missing points. For a multivariate record, multi-channel SSA imputation takes advantage of both spatial and temporal correlations. Analyzing the whole available record with the missing points filled, allows for greater accuracy and better significance testing in the spectral analysis. It also provides information on the evolution of the oscillatory modes in the gaps. We use cross-validation to optimize the SSA window width and number of SSA modes to fill the gaps. The algorithm is applied to the extended (A.D. 622--1922) historical records of the low- and high-water levels of the Nile River at Cairo. We fill in the large gaps in the later part of the records (A.D. 1471--1922), and identify statistically significant interannual and interdecadal periodicities. Our analysis suggests that the 7-year periodicity in the records, possibly related to the biblical "Joseph" cycle, is due to North-Atlantic influences. We find that the climate shifts at the beginning and the end of the Medieval Warm Period were fairly abrupt and affected several climatic modes of variability.

  15. Method and apparatus for frequency spectrum analysis

    NASA Technical Reports Server (NTRS)

    Cole, Steven W. (Inventor)

    1992-01-01

    A method for frequency spectrum analysis of an unknown signal in real-time is discussed. The method is based upon integration of 1-bit samples of signal voltage amplitude corresponding to sine or cosine phases of a controlled center frequency clock which is changed after each integration interval to sweep the frequency range of interest in steps. Integration of samples during each interval is carried out over a number of cycles of the center frequency clock spanning a number of cycles of an input signal to be analyzed. The invention may be used to detect the frequency of at least two signals simultaneously. By using a reference signal of known frequency and voltage amplitude (added to the two signals for parallel processing in the same way, but in a different channel with a sampling at the known frequency and phases of the reference signal), the absolute voltage amplitude of the other two signals may be determined by squaring the sine and cosine integrals of each channel and summing the squares to obtain relative power measurements in all three channels and, from the known voltage amplitude of the reference signal, obtaining an absolute voltage measurement for the other two signals by multiplying the known voltage of the reference signal with the ratio of the relative power of each of the other two signals to the relative power of the reference signal.

  16. GRABGAM Analysis of Ultra-Low-Level HPGe Gamma Spectra

    SciTech Connect

    Winn, W.G.

    1999-07-28

    The GRABGAM code has been used successfully for ultra-low level HPGe gamma spectrometry analysis since its development in 1985 at Savannah River Technology Center (SRTC). Although numerous gamma analysis codes existed at that time, reviews of institutional and commercial codes indicated that none addressed all features that were desired by SRTC. Furthermore, it was recognized that development of an in-house code would better facilitate future evolution of the code to address SRTC needs based on experience with low-level spectra. GRABGAM derives its name from Gamma Ray Analysis BASIC Generated At MCA/PC.

  17. Application of spectrum shifting methodology to restore NaI(Tl)-recorded gamma spectra, shifted due to temperature variations in the environment.

    PubMed

    Mitra, Pratip; Roy, Arup Singha; Verma, Amit K; Pant, Amar D; Prakasha, M S; Anilkumar, S; Kumar, A Vinod

    2016-01-01

    A method has been standardized for restoring a shifted differential pulse height spectrum from a scintillator based gamma ray spectrometer recorded at measurement temperature, to the position of a desired spectrum, recorded at a reference temperature. The method is based on the assumption that the spectrum obtained at measurement temperature represents the same statistical distribution as that at reference temperature but with different energy scales. A computer program has been developed for calculation of the transformation between the energy scales and for the restoration of the shifted spectrum. The method developed has been successfully applied for the restoration of gamma spectra measured at different temperatures. PMID:26492324

  18. Radiative-neutron-capture gamma-ray analysis by a linear combination technique

    USGS Publications Warehouse

    Tanner, A.B.; Bhargava, R.C.; Senftle, F.E.; Brinkerhoff, J.M.

    1972-01-01

    The linear combination technique, when applied to a gamma-ray spectrum, gives a single number indicative of the extent to which the spectral lines of a sought element are present in a complex spectrum. Spectra are taken of the sought element and of various other substances whose spectra interfere with that of the sought element. A weighting function is then computed for application to spectra of unknown materials. The technique was used to determine calcium by radiative-neutron-capture gamma-ray analysis in the presence of interfering elements, notably titanium, and the results were compared with those for two popular methods of peak area integration. Although linearity of response was similar for the methods, the linear combination technique was much better at rejecting interferences. For analyses involving mixtures of unknown composition the technique consequently offers improved sensitivity. ?? 1972.

  19. Decision Analysis of Dynamic Spectrum Access Rules

    SciTech Connect

    Juan D. Deaton; Luiz A. DaSilva; Christian Wernz

    2011-12-01

    A current trend in spectrum regulation is to incorporate spectrum sharing through the design of spectrum access rules that support Dynamic Spectrum Access (DSA). This paper develops a decision-theoretic framework for regulators to assess the impacts of different decision rules on both primary and secondary operators. We analyze access rules based on sensing and exclusion areas, which in practice can be enforced through geolocation databases. Our results show that receiver-only sensing provides insufficient protection for primary and co-existing secondary users and overall low social welfare. On the other hand, using sensing information between the transmitter and receiver of a communication link, provides dramatic increases in system performance. The performance of using these link end points is relatively close to that of using many cooperative sensing nodes associated to the same access point and large link exclusion areas. These results are useful to regulators and network developers in understanding in developing rules for future DSA regulation.

  20. Power spectrum analysis of staggered quadriphase-shift-keyed signals

    NASA Technical Reports Server (NTRS)

    Mcwhorter, F. L.; Cartier, D. E.

    1975-01-01

    Mathematical analysis of power spectrum of outputs from high-reliability communication system is used to determine system bandwidth. Analysis provides mathematical relationships of signal power spectrum at output of hard limiter for any type of baseband pulse input subjected only to output parameter constraints.

  1. Gamma-Ray Library and Uncertainty Analysis: Passively Emitted Gamma Rays Used in Safeguards Technology

    SciTech Connect

    Parker, W

    2009-09-18

    Non-destructive gamma-ray analysis is a fundamental part of nuclear safeguards, including nuclear energy safeguards technology. Developing safeguards capabilities for nuclear energy will certainly benefit from the advanced use of gamma-ray spectroscopy as well as the ability to model various reactor scenarios. There is currently a wide variety of nuclear data that could be used in computer modeling and gamma-ray spectroscopy analysis. The data can be discrepant (with varying uncertainties), and it may difficult for a modeler or software developer to determine the best nuclear data set for a particular situation. To use gamma-ray spectroscopy to determine the relative isotopic composition of nuclear materials, the gamma-ray energies and the branching ratios or intensities of the gamma-rays emitted from the nuclides in the material must be well known. A variety of computer simulation codes will be used during the development of the nuclear energy safeguards, and, to compare the results of various codes, it will be essential to have all the {gamma}-ray libraries agree. Assessing our nuclear data needs allows us to create a prioritized list of desired measurements, and provides uncertainties for energies and especially for branching intensities. Of interest are actinides, fission products, and activation products, and most particularly mixtures of all of these radioactive isotopes, including mixtures of actinides and other products. Recent work includes the development of new detectors with increased energy resolution, and studies of gamma-rays and their lines used in simulation codes. Because new detectors are being developed, there is an increased need for well known nuclear data for radioactive isotopes of some elements. Safeguards technology should take advantage of all types of gamma-ray detectors, including new super cooled detectors, germanium detectors and cadmium zinc telluride detectors. Mixed isotopes, particularly mixed actinides found in nuclear reactor

  2. Gamma analysis of environmental samples from the Marshall Islands

    SciTech Connect

    Brunk, J.L.

    1995-09-01

    Radiological studies of the fate of nuclear test related debris in the Marshall Islands conducted by members of the Lawrence Livermore National Laboratory generate large number of environmental samples. For more than 20 years, the Low-Level Gamma Spectroscopy Facility has been used to perform the analysis of gamma emitting radionuclides. A brief description of the facility, calibration, counting and analysis procedures is given.

  3. Measurement of the B to Xs gammaBranching Fraction and Photon Energy Spectrum usingthe Recoil Method

    SciTech Connect

    Aubert, B.

    2007-12-04

    We present a measurement of the branching fraction and photon energy spectrum for the decay B {yields} X{sub s}{gamma} using data from the BABAR experiment. The data sample corresponds to an integrated luminosity of 210 fb{sup -1}, from which approximately 680,000 B{bar B} events are tagged by a fully reconstructed hadronic decay of one of the B mesons. In the decay of the second B meson, an isolated high-energy photon is identified. We measure {Beta}(B {yields} X{sub s}{gamma}) = (3.66 {+-} 0.85{sub stat} {+-} 0.60{sub syst}) x 10{sup -4} for photon energies E{sub {gamma}} above 1.9 GeV in the B rest frame. From the measured spectrum we calculate the first and second moments for different minimum photon energies, which are used to extract the heavy-quark parameters m{sub b} and {mu}{sub {pi}}{sup 2}. In addition, measurements of the direct CP asymmetry and isospin asymmetry are presented.

  4. Determining the isotopic concentration of uranium from vector representation of the gamma spectrum

    NASA Astrophysics Data System (ADS)

    White, Tristan Glover

    Gamma emissions from Uranium-235 in a source of interest were compared to gamma emissions from Protactinium-234m (which is in equilibrium with Uranium-238) in order to determine the isotopic composition of the source. The 144 keV gamma ray from U-235 was compared with 1001 keV gamma ray from Pa-234m. Two analytical methods were compared: the relative activity method and the vector representation method. The relative activity method is similar to the (standard) relative intensity method, but accounts for more variables. Calculations were performed using both methods in order to evaluate precision and accuracy. Relative activity compares the number of counts under one gamma-ray peak from a reference source to the number of counts under another peak from an unknown source. This method is sensitive to systematic errors in the efficiency calibration of the detector when two different peaks with different energies are used. Vector representation compares the count ratio of two gamma-ray peaks from one source to the count ratio of the same two gamma-ray peaks from another source. Vector representation was found to be practical for analyzing depleted uranium, but not highly enriched uranium (HEU), due to different branching ratios and detector efficiency.

  5. An optical spectrum of the afterglow of a gamma-ray burst at a redshift of z = 6.295.

    PubMed

    Kawai, N; Kosugi, G; Aoki, K; Yamada, T; Totani, T; Ohta, K; Iye, M; Hattori, T; Aoki, W; Furusawa, H; Hurley, K; Kawabata, K S; Kobayashi, N; Komiyama, Y; Mizumoto, Y; Nomoto, K; Noumaru, J; Ogasawara, R; Sato, R; Sekiguchi, K; Shirasaki, Y; Suzuki, M; Takata, T; Tamagawa, T; Terada, H; Watanabe, J; Yatsu, Y; Yoshida, A

    2006-03-01

    The prompt gamma-ray emission from gamma-ray bursts (GRBs) should be detectable out to distances of z > 10 (ref. 1), and should therefore provide an excellent probe of the evolution of cosmic star formation, reionization of the intergalactic medium, and the metal enrichment history of the Universe. Hitherto, the highest measured redshift for a GRB has been z = 4.50 (ref. 5). Here we report the optical spectrum of the afterglow of GRB 050904 obtained 3.4 days after the burst; the spectrum shows a clear continuum at the long-wavelength end of the spectrum with a sharp cut-off at around 9,000 A due to Lyman alpha absorption at z approximately 6.3 (with a damping wing). A system of absorption lines of heavy elements at z = 6.295 +/- 0.002 was also detected, yielding the precise measurement of the redshift. The Si ii fine-structure lines suggest a dense, metal-enriched environment around the progenitor of the GRB.

  6. An optical spectrum of the afterglow of a gamma-ray burst at a redshift of z = 6.295.

    PubMed

    Kawai, N; Kosugi, G; Aoki, K; Yamada, T; Totani, T; Ohta, K; Iye, M; Hattori, T; Aoki, W; Furusawa, H; Hurley, K; Kawabata, K S; Kobayashi, N; Komiyama, Y; Mizumoto, Y; Nomoto, K; Noumaru, J; Ogasawara, R; Sato, R; Sekiguchi, K; Shirasaki, Y; Suzuki, M; Takata, T; Tamagawa, T; Terada, H; Watanabe, J; Yatsu, Y; Yoshida, A

    2006-03-01

    The prompt gamma-ray emission from gamma-ray bursts (GRBs) should be detectable out to distances of z > 10 (ref. 1), and should therefore provide an excellent probe of the evolution of cosmic star formation, reionization of the intergalactic medium, and the metal enrichment history of the Universe. Hitherto, the highest measured redshift for a GRB has been z = 4.50 (ref. 5). Here we report the optical spectrum of the afterglow of GRB 050904 obtained 3.4 days after the burst; the spectrum shows a clear continuum at the long-wavelength end of the spectrum with a sharp cut-off at around 9,000 A due to Lyman alpha absorption at z approximately 6.3 (with a damping wing). A system of absorption lines of heavy elements at z = 6.295 +/- 0.002 was also detected, yielding the precise measurement of the redshift. The Si ii fine-structure lines suggest a dense, metal-enriched environment around the progenitor of the GRB. PMID:16525466

  7. Application of egs4 computer code for determination of gamma ray spectrum and dose rate distribution in gammacell 220

    NASA Astrophysics Data System (ADS)

    Raisali, G. R.; Sohrabpour, M.

    1993-10-01

    The EGS4 a Monte Carlo electron-photon transport simulation package together with a locally developed computer program "GCELL" has been used to simulate the transport of the gamma rays in Gammacell 220. An additional lead attenuator has been inserted in the chamber, has been included for those cases where lower dose rates were required. For three cases of 0, 1.35 and 4.0 cm thickness of added lead attenuators, the gamma spectrum, and dose rate distribution inside the chamber have been determined. For the case of no attenuator present, the main shield around the source cage has been included in the simulation program and its albedo effects have been investigated. The calculated dose rate distribution in the Gammacell chamber has been compared against measurements carried out with Fricke, PMMA and Gafchromic film dosimeters.

  8. IMPLEMENTING THE STANDARD SPECTRUM METHOD FOR ANALYSIS OF β-γ COINCIDENCE SPECTRA

    SciTech Connect

    Biegalski, S.; Flory, Adam E.; Schrom, Brian T.; Ely, James H.; Haas, Derek A.; Bowyer, Ted W.; Hayes, James C.

    2011-09-14

    The standard deconvolution analysis tool (SDAT) algorithms were developed and tested at the University of Texas at Austin. These algorithms utilize the standard spectrum technique for spectral analysis of {beta}-{gamma} coincidence spectra for nuclear explosion monitoring. Work has been conducted under this contract to implement these algorithms into a useable scientific software package with a graphical user interface. Improvements include the ability to read in PHD formatted data, gain matching, and data visualization. New auto-calibration algorithms were developed and implemented based on 137Cs spectra for assessment of the energy vs. channel calibrations. Details on the user tool and testing are included.

  9. A celestial gamma-ray foreground due to the albedo of small solar system bodies and a remote probe of the interstellar cosmic ray spectrum

    SciTech Connect

    Moskalenko, Igor V.; Porter, Troy A.; Digel, Seth W.; Michelson, Peter F.; Ormes, Jonathan F.

    2007-12-17

    We calculate the {gamma}-ray albedo flux from cosmic-ray (CR) interactions with the solid rock and ice in Main Belt asteroids and Kuiper Belt objects (KBOs) using the Moon as a template. We show that the {gamma}-ray albedo for the Main Belt and Kuiper Belt strongly depends on the small-body mass spectrum of each system and may be detectable by the forthcoming Gamma Ray Large Area Space Telescope (GLAST). The orbits of the Main Belt asteroids and KBOs are distributed near the ecliptic, which passes through the Galactic center and high Galactic latitudes. If detected, the {gamma}-ray emission by the Main Belt and Kuiper Belt has to be taken into account when analyzing weak {gamma}-ray sources close to the ecliptic, especially near the Galactic center and for signals at high Galactic latitudes, such as the extragalactic {gamma}-ray emission. Additionally, it can be used to probe the spectrum of CR nuclei at close-to-interstellar conditions, and the mass spectrum of small bodies in the Main Belt and Kuiper Belt. The asteroid albedo spectrum also exhibits a 511 keV line due to secondary positrons annihilating in the rock. This may be an important and previously unrecognized celestial foreground for the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of the Galactic 511 keV line emission including the direction of the Galactic center.

  10. Effects of velocity-dependent dark matter annihilation on the energy spectrum of the extragalactic gamma-ray background

    NASA Astrophysics Data System (ADS)

    Campbell, Sheldon; Dutta, Bhaskar; Komatsu, Eiichiro

    2010-11-01

    We calculate the effects of velocity-dependent dark matter annihilation cross sections on the intensity of the extragalactic gamma-ray background. Our formalism does not assume a locally thermal distribution of dark matter particles in phase space, and is valid for arbitrary velocity-dependent annihilation. Although the model of the dark matter distribution we use is simple and may not describe nature precisely, it is sufficient for quantifying the effects of velocity-dependent annihilations: different halo models would be expected to produce the same general features. As concrete examples, we calculate the effects of p-wave annihilation (with the v-weighted cross section of σv=a+bv2) on the mean intensity of extragalactic gamma rays produced in cosmological dark matter halos. This velocity variation makes the shape of the energy spectrum harder, but this change in the shape is too small to see unless b/a≳106. While we find no such models in the parameter space of the minimal supersymmetric standard model, we show that it is possible to find b/a≳106 in the extension MSSM⊗U(1)B-L. However, we find that the most dominant effect of the p-wave annihilation is the suppression of the amplitude of the gamma-ray background. A nonzero b at the dark matter freeze-out epoch requires a smaller value of a in order for the relic density constraint to be satisfied, suppressing the amplitude by a factor as low as 10-6 for a thermal relic. Nonthermal relics will have weaker amplitude suppression. As another velocity-dependent effect, we calculate the spectrum for s-wave annihilation into fermions enhanced by the attractive Sommerfeld effect. Resonances associated with this effect result in significantly enhanced intensities, with a slightly softer energy spectrum.

  11. Total Gamma Count Rate Analysis Method for Nondestructive Assay Characterization

    SciTech Connect

    Cecilia R. Hoffman; Yale D. Harker

    2006-03-01

    A new approach to nondestructively characterize waste for disposal, based on total gamma response, has been developed at the Idaho Cleanup Project by CH2M-WG Idaho, LLC and Idaho State University, and is called the total gamma count rate analysis method. The total gamma count rate analysis method measures gamma interactions that produce energetic electrons or positrons in a detector. Based on previous experience with waste assays, the radionuclide content of the waste container is then determined. This approach potentially can yield minimum detection limits of less than 10 nCi/g. The importance of this method is twofold. First, determination of transuranic activity can be made for waste containers that are below the traditional minimum detection limits. Second, waste above 10 nCi/g and below 100 nCi/g can be identified, and a potential path for disposal resolved.

  12. Development of Mirror Modules for the ART-XC Instrument aboard the Spectrum-Roentgen-Gamma Mission

    NASA Technical Reports Server (NTRS)

    Gubarev, Mikhail V.; Ramsey, Brian; O'Dell, Stephen L.; Elsner, Ronald F.; Kilaru, Kiranmayee; Atkins, Carolyn; Pavlinskiy, Mikhail N.; Tkachenko, Alexey V.; Lapshov, Igor Y.

    2013-01-01

    The Marshall Space Flight Center (MSFC) is developing x-ray mirror modules for the Astronomical Roengen Telescope- X-ray Concentrator (ART-XC) instrument on board the Spectrum-Roentgen-Gamma Mission. ART-XC will consist of seven co-aligned x-ray mirror modules with seven corresponding CdTe focal plane detectors. Each module provides an effective area of 65 sq cm at 8 keV, response out to 30 keV, and an angular resolution of 45 arcsec or better HPD. We will present a status of the ART x-ray module development at MSFC.

  13. A mass spectrometric analysis of {gamma}-GPS films

    SciTech Connect

    Dillingham, R.G.; Boerio, F.J.; Bertelsen, C.; Savina, M.R.; Lykke, K.R.; Calaway, W.F.

    1996-06-01

    {gamma}-glycidoxypropyltrimethoxysilane ({gamma}-GPS) is used for pre-treatment of grit-blasted aluminum before adhesive bonding. This paper discusses analysis of non-reflective grit-blasted surfaces using mass spectrometry of species that were either sputtered off using an ion beam or thermally desorbed as neutrals using a pulsed laser and then post-ionized using a secondary laser. Results show that fragmentation is excessive and structural information is difficult to obtain from the spectra.

  14. Spectrum Analysis of Some Kinetic Equations

    NASA Astrophysics Data System (ADS)

    Yang, Tong; Yu, Hongjun

    2016-11-01

    We analyze the spectrum structure of some kinetic equations qualitatively by using semigroup theory and linear operator perturbation theory. The models include the classical Boltzmann equation for hard potentials with or without angular cutoff and the Landau equation with {γ≥q-2}. As an application, we show that the solutions to these two fundamental equations are asymptotically equivalent (mod time decay rate {t^{-5/4}}) as {tto∞} to that of the compressible Navier-Stokes equations for initial data around an equilibrium state.

  15. Modeling of neutron spectrum in the gamma spectroscopy measurements with Ge-detectors

    NASA Astrophysics Data System (ADS)

    Knežević, D.; Jovančević, N.; Krmar, M.; Petrović, J.

    2016-10-01

    In this study, we present a novel approach for estimation of neutron spectra that are present during gamma spectroscopy measurements performed by a Ge detector. This method is based on the calculation of the neutron spectra by using an unfolding procedure, where the activity of the Ge isotopes, produced by the neutron reactions, and the available cross section data for those reactions are the input parameters. This new approach was tested by background gamma spectroscopy measurements with a HPGe detector. Obtained results show that this method can provide useful information about the neutron spectra at the position of the Ge detectors.

  16. The development of a new edition of the gamma-ray spectrum catalogues designed for presentation in electronic format

    SciTech Connect

    Heath, R.L.

    1997-11-01

    New editions of the original Gamma-ray Spectrum Catalogues are being prepared for publication in electronic format. The objective of this program is to produce versions of the Catalogues in CD-ROM format and as an Internet resource. Additions to the original content of the Catalogues will include integrated decay scheme drawings, tables of related decay data, and updated text on the techniques of gamma-ray spectrometry. Related decay data from the Evaluated Nuclear Structure Data File (ENSDF) are then added, and all data converted to the Adobe Acrobat (PDF) format for CD-ROM production and availability on the large-volume Ge detectors, alpha-particle spectra, prompt neutron capture and inelastic scattering gamma-ray spectra, and gross fission product spectra characteristic of fuel cycle waste materials. Characterization of radioactivity in materials is a requirement in many phases of radioactive waste management. Movement, shipping, treatment, all activities which involve handling of mixed waste or TRU categories of waste at all DOE sites will require that measurements and assessment documentation utilize basic nuclear data which are tracable to internationally accepted standard values. This program will involve the identification of data needs unique to the development and application of specialized detector systems for radioactive waste characterization. 8 refs., 8 figs.

  17. Formation of very hard electron and gamma-ray spectra of flat-spectrum radio quasars in the fast-cooling regime

    NASA Astrophysics Data System (ADS)

    Yan, Dahai; Zhang, Li; Zhang, Shuang-Nan

    2016-07-01

    In the external Compton scenario, we investigate the formation of a very hard electron spectrum in the fast-cooling regime, using a time-dependent emission model. It is shown that a very hard electron distribution, N^' }_e({γ ^' })∝ {γ ^' }^{-p}, with spectral index p ˜ 1.3 is formed below the minimum energy of injection electrons when inverse Compton scattering takes place in the Klein-Nishina regime, i.e. inverse Compton scattering of relativistic electrons on broad-line region radiation in flat-spectrum radio quasars. This produces a very hard gamma-ray spectrum and can explain in reasonable fashion the very hard Fermi-Large Area Telescope (LAT) spectrum of the flat-spectrum radio quasar 3C 279 during the extreme gamma-ray flare in 2013 December.

  18. Gamma bang time analysis at OMEGA.

    PubMed

    McEvoy, A M; Herrmann, H W; Horsfield, C J; Young, C S; Miller, E K; Mack, J M; Kim, Y; Stoeffl, W; Rubery, M; Evans, S; Sedillo, T; Ali, Z A

    2010-10-01

    Absolute bang time measurements with the gas Cherenkov detector (GCD) and gamma reaction history (GRH) diagnostic have been performed to high precision at the OMEGA laser facility at the University of Rochester with bang time values for the two diagnostics agreeing to within 5 ps on average. X-ray timing measurements of laser-target coupling were used to calibrate a facility-generated laser timing fiducial with rms spreads in the measured coupling times of 9 ps for both GCD and GRH. Increased fusion yields at the National Ignition Facility (NIF) will allow for improved measurement precision with the GRH easily exceeding NIF system design requirements. PMID:21033846

  19. Gamma bang time analysis at OMEGA

    SciTech Connect

    McEvoy, A. M.; Herrmann, H. W.; Young, C. S.; Mack, J. M.; Kim, Y.; Evans, S.; Sedillo, T.; Horsfield, C. J.; Rubery, M.; Miller, E. K.; Stoeffl, W.; Ali, Z. A.

    2010-10-15

    Absolute bang time measurements with the gas Cherenkov detector (GCD) and gamma reaction history (GRH) diagnostic have been performed to high precision at the OMEGA laser facility at the University of Rochester with bang time values for the two diagnostics agreeing to within 5 ps on average. X-ray timing measurements of laser-target coupling were used to calibrate a facility-generated laser timing fiducial with rms spreads in the measured coupling times of 9 ps for both GCD and GRH. Increased fusion yields at the National Ignition Facility (NIF) will allow for improved measurement precision with the GRH easily exceeding NIF system design requirements.

  20. Covariance analysis of gamma ray spectra

    SciTech Connect

    Trainham, R.; Tinsley, J.

    2013-01-15

    The covariance method exploits fluctuations in signals to recover information encoded in correlations which are usually lost when signal averaging occurs. In nuclear spectroscopy it can be regarded as a generalization of the coincidence technique. The method can be used to extract signal from uncorrelated noise, to separate overlapping spectral peaks, to identify escape peaks, to reconstruct spectra from Compton continua, and to generate secondary spectral fingerprints. We discuss a few statistical considerations of the covariance method and present experimental examples of its use in gamma spectroscopy.

  1. Covariance Analysis of Gamma Ray Spectra

    SciTech Connect

    Trainham, R.; Tinsley, J.

    2013-01-01

    The covariance method exploits fluctuations in signals to recover information encoded in correlations which are usually lost when signal averaging occurs. In nuclear spectroscopy it can be regarded as a generalization of the coincidence technique. The method can be used to extract signal from uncorrelated noise, to separate overlapping spectral peaks, to identify escape peaks, to reconstruct spectra from Compton continua, and to generate secondary spectral fingerprints. We discuss a few statistical considerations of the covariance method and present experimental examples of its use in gamma spectroscopy.

  2. Gamma bang time analysis at OMEGAa)

    NASA Astrophysics Data System (ADS)

    McEvoy, A. M.; Herrmann, H. W.; Horsfield, C. J.; Young, C. S.; Miller, E. K.; Mack, J. M.; Kim, Y.; Stoeffl, W.; Rubery, M.; Evans, S.; Sedillo, T.; Ali, Z. A.

    2010-10-01

    Absolute bang time measurements with the gas Cherenkov detector (GCD) and gamma reaction history (GRH) diagnostic have been performed to high precision at the OMEGA laser facility at the University of Rochester with bang time values for the two diagnostics agreeing to within 5 ps on average. X-ray timing measurements of laser-target coupling were used to calibrate a facility-generated laser timing fiducial with rms spreads in the measured coupling times of 9 ps for both GCD and GRH. Increased fusion yields at the National Ignition Facility (NIF) will allow for improved measurement precision with the GRH easily exceeding NIF system design requirements.

  3. The SNAP 27 gamma radiation spectrum obtained with a Ge/Li/ detector

    NASA Technical Reports Server (NTRS)

    Taherzadeh, M.

    1976-01-01

    The pulse height distribution, obtained experimentally using a Ge(Li) detector, was employed to determine the photon emission rate characteristic of a PuO2 fuel source known as the SNAP 27 heat source. The selfshielding parameters of the photon emitter, the efficiency of the detector and the geometry of the experiment were utilized to determine the unscattered photon emission rate of the source and the unscattered flux spectrum at a certain specified distance from the source. For the scattered part of the flux spectrum a Monte Carlo technique was employed so that the total flux spectrum could be determined at any point in the radiation field. As a result of this work, a technique was developed to obtain the unfolded radiation spectrum of the SNAP 27 heat source.

  4. ENERGY-DEPENDENT GAMMA-RAY BURST PULSE WIDTH DUE TO THE CURVATURE EFFECT AND INTRINSIC BAND SPECTRUM

    SciTech Connect

    Peng, Z. Y.; Ma, L.; Zhao, X. H.; Yin, Y.; Bao, Y. Y.

    2012-06-20

    Previous studies have found that the width of the gamma-ray burst (GRB) pulse is energy dependent and that it decreases as a power-law function with increasing photon energy. In this work we have investigated the relation between the energy dependence of the pulse and the so-called Band spectrum by using a sample including 51 well-separated fast rise and exponential decay long-duration GRB pulses observed by BATSE (Burst and Transient Source Experiment on the Compton Gamma Ray Observatory). We first decompose these pulses into rise and decay phases and find that the rise widths and the decay widths also behave as a power-law function with photon energy. Then we investigate statistically the relations between the three power-law indices of the rise, decay, and total width of the pulse (denoted as {delta}{sub r}, {delta}{sub d}, and {delta}{sub w}, respectively) and the three Band spectral parameters, high-energy index ({alpha}), low-energy index ({beta}), and peak energy (E{sub p} ). It is found that (1) {alpha} is strongly correlated with {delta}{sub w} and {delta}{sub d} but seems uncorrelated with {delta}{sub r}; (2) {beta} is weakly correlated with the three power-law indices, and (3) E{sub p} does not show evident correlations with the three power-law indices. We further investigate the origin of {delta}{sub d}-{alpha} and {delta}{sub w}-{alpha}. We show that the curvature effect and the intrinsic Band spectrum could naturally lead to the energy dependence of the GRB pulse width and also the {delta}{sub d}-{alpha} and {delta}{sub w}-{alpha} correlations. Our results hold so long as the shell emitting gamma rays has a curved surface and the intrinsic spectrum is a Band spectrum or broken power law. The strong {delta}{sub d}-{alpha} correlation and inapparent correlations between {delta}{sub r} and the three Band spectral parameters also suggest that the rise and decay phases of the GRB pulses have different origins.

  5. Terahertz wave spectrum analysis of microstrip structure

    NASA Astrophysics Data System (ADS)

    Song, Mei-jing; Li, Jiu-sheng

    2011-11-01

    Terahertz wave is a kind of electromagnetic wave ranging from 0.1~10THz, between microwave and infrared, which occupies a special place in the electromagnetic spectrum. Terahertz radiation has a strong penetration for many media materials and nonpolar substance, for example, dielectric material, plastic, paper carton and cloth. In recent years, researchers around the world have paid great attention on terahertz technology, such as safety inspection, chemical biology, medical diagnosis and terahertz wave imaging, etc. Transmission properties of two-dimensional metal microstrip structures in the terahertz regime are presented and tested. Resonant terahertz transmission was demonstrated in four different arrays of subwavelength microstrip structure patterned on semiconductor. The effects of microstrip microstrip structure shape were investigated by using terahertz time-domain spectroscopy system. The resonant terahertz transmission has center frequency of 2.05 THz, transmission of 70%.

  6. Terahertz wave spectrum analysis of microstrip structure

    NASA Astrophysics Data System (ADS)

    Song, Mei-jing; Li, Jiu-sheng

    2012-03-01

    Terahertz wave is a kind of electromagnetic wave ranging from 0.1~10THz, between microwave and infrared, which occupies a special place in the electromagnetic spectrum. Terahertz radiation has a strong penetration for many media materials and nonpolar substance, for example, dielectric material, plastic, paper carton and cloth. In recent years, researchers around the world have paid great attention on terahertz technology, such as safety inspection, chemical biology, medical diagnosis and terahertz wave imaging, etc. Transmission properties of two-dimensional metal microstrip structures in the terahertz regime are presented and tested. Resonant terahertz transmission was demonstrated in four different arrays of subwavelength microstrip structure patterned on semiconductor. The effects of microstrip microstrip structure shape were investigated by using terahertz time-domain spectroscopy system. The resonant terahertz transmission has center frequency of 2.05 THz, transmission of 70%.

  7. Baryon Spectrum Analysis using Covariant Constraint Dynamics

    NASA Astrophysics Data System (ADS)

    Whitney, Joshua; Crater, Horace

    2012-03-01

    The energy spectrum of the baryons is determined by treating each of them as a three-body system with the interacting forces coming from a set of two-body potentials that depend on both the distance between the quarks and the spin and orbital angular momentum coupling terms. The Two Body Dirac equations of constraint dynamics derived by Crater and Van Alstine, matched with the quasipotential formalism of Todorov as the underlying two-body formalism are used, as well as the three-body constraint formalism of Sazdjian to integrate the three two-body equations into a single relativistically covariant three body equation for the bound state energies. The results are analyzed and compared to experiment using a best fit method and several different algorithms, including a gradient approach, and Monte Carlo method. Results for all well-known baryons are presented and compared to experiment, with good accuracy.

  8. Spectrum analysis with quantum dynamical systems

    NASA Astrophysics Data System (ADS)

    Ng, Shilin; Ang, Shan Zheng; Wheatley, Trevor A.; Yonezawa, Hidehiro; Furusawa, Akira; Huntington, Elanor H.; Tsang, Mankei

    2016-04-01

    Measuring the power spectral density of a stochastic process, such as a stochastic force or magnetic field, is a fundamental task in many sensing applications. Quantum noise is becoming a major limiting factor to such a task in future technology, especially in optomechanics for temperature, stochastic gravitational wave, and decoherence measurements. Motivated by this concern, here we prove a measurement-independent quantum limit to the accuracy of estimating the spectrum parameters of a classical stochastic process coupled to a quantum dynamical system. We demonstrate our results by analyzing the data from a continuous-optical-phase-estimation experiment and showing that the experimental performance with homodyne detection is close to the quantum limit. We further propose a spectral photon-counting method that can attain quantum-optimal performance for weak modulation and a coherent-state input, with an error scaling superior to that of homodyne detection at low signal-to-noise ratios.

  9. Reanalysis of the Apollo cosmic gamma-ray spectrum in the 0.3 to 10 MeV energy region

    NASA Technical Reports Server (NTRS)

    Trombka, J. I.; Dyer, C. S.; Evans, L. G.; Bielefeld, M. J.; Seltzer, S. M.; Metzger, A. E.

    1976-01-01

    Additional data obtained from the Apollo-16 and -17 missions, together with collateral calculations on background radiation effects, have enabled an improved subtraction of unwanted backgrounds from the diffuse cosmic gamma-ray data previously reported from Apollo-15. As a result, the 1- to 10-MeV spectrum is lowered significantly and connects smoothly with recent data at other energies. The inflection reported previously is much less pronounced and has no more than a 1.5-sigma significance. Sky occultation by the Apollo-16 spacecraft shows the bulk of the 0.3- to 1-MeV radiation to be diffuse. The analysis of spurious backgrounds points to important improvements for future experiments designed for this spectral region.

  10. Reanalysis of the Apollo cosmic gamma-ray spectrum in the 0.3 to 10 MeV energy region

    NASA Technical Reports Server (NTRS)

    Trombka, J. I.; Dyer, C. S.; Evans, L. G.; Bielefeld, M. J.; Seltzer, S. M.; Metzger, A. E.

    1977-01-01

    Additional data obtained from the Apollo 16 and Apollo 17 missions, together with collateral calculations on background radiation effects, have made possible an improved subtraction of unwanted backgrounds from the diffuse cosmic gamma-ray data previously reported from Apollo 15. As a result, the 1- to 10-MeV spectrum is lowered significantly and connects smoothly with recent data at other energies. The inflection reported previously is much less pronounced and has no more than a 1.5-sigma significance. Sky occultation by the Apollo 16 spacecraft shows the bulk of the 0.3- to 1-MeV radiation to be diffuse. The analysis of spurious backgrounds points to important improvements for future experiments designed for this spectral region.

  11. Heart sound biometric system based on marginal spectrum analysis.

    PubMed

    Zhao, Zhidong; Shen, Qinqin; Ren, Fangqin

    2013-02-18

    This work presents a heart sound biometric system based on marginal spectrum analysis, which is a new feature extraction technique for identification purposes. This heart sound identification system is comprised of signal acquisition, pre-processing, feature extraction, training, and identification. Experiments on the selection of the optimal values for the system parameters are conducted. The results indicate that the new spectrum coefficients result in a significant increase in the recognition rate of 94.40% compared with that of the traditional Fourier spectrum (84.32%) based on a database of 280 heart sounds from 40 participants. 

  12. Heart Sound Biometric System Based on Marginal Spectrum Analysis

    PubMed Central

    Zhao, Zhidong; Shen, Qinqin; Ren, Fangqin

    2013-01-01

    This work presents a heart sound biometric system based on marginal spectrum analysis, which is a new feature extraction technique for identification purposes. This heart sound identification system is comprised of signal acquisition, pre-processing, feature extraction, training, and identification. Experiments on the selection of the optimal values for the system parameters are conducted. The results indicate that the new spectrum coefficients result in a significant increase in the recognition rate of 94.40% compared with that of the traditional Fourier spectrum (84.32%) based on a database of 280 heart sounds from 40 participants. PMID:23429515

  13. Spectrum of {gamma} rays connecting superdeformed and normal states in {sup 192}Hg

    SciTech Connect

    Henry, R.G.; Lauritsen, T.; Khoo, T.L.

    1995-08-01

    Almost a hundred superdeformed bands were found in the mass 150 and 190 regions. Nevertheless, the energies and spins of the SD levels are still not measured (with one possible exception). Many attempts were made to decipher the highly-fragmented pathways connecting SD and normal states, but with hitherto no success. We adopted a new approach that consists of characterizing the overall spectral shape of the {gamma} rays linking SD and normal states.

  14. High-energy gamma-ray emission from solar flares: Constraining the accelerated proton spectrum

    NASA Technical Reports Server (NTRS)

    Alexander, David; Dunphy, Philip P.; Mackinnon, Alexander L.

    1994-01-01

    Using a multi-component model to describe the gamma-ray emission, we investigate the flares of December 16, 1988 and March 6, 1989 which exhibited unambiguous evidence of neutral pion decay. The observations are then combined with theoretical calculations of pion production to constrain the accelerated proton spectra. The detection of pi(sup 0) emission alone can indicate much about the energy distribution and spectral variation of the protons accelerated to pion producing energies. Here both the intensity and detailed spectral shape of the Doppler-broadened pi(sup 0) decay feature are used to determine the spectral form of the accelerated proton energy distribution. The Doppler width of this gamma-ray emission provides a unique diagnostic of the spectral shape at high energies, independent of any normalisation. To our knowledge, this is the first time that this diagnostic has been used to constrain the proton spectra. The form of the energetic proton distribution is found to be severely limited by the observed intensity and Doppler width of the pi(sup 0) decay emission, demonstrating effectively the diagnostic capabilities of the pi(sup 0) decay gamma-rays. The spectral index derived from the gamma-ray intensity is found to be much harder than that derived from the Doppler width. To reconcile this apparent discrepancy we investigate the effects of introducing a high-energy cut-off in the accelerated proton distribution. With cut-off energies of around 0.5-0.8 GeV and relatively hard spectra, the observed intensities and broadening can be reproduced with a single energetic proton distribution above the pion production threshold.

  15. Angular Signatures of Dark Matter in the Diffuse Gamma Ray Spectrum

    SciTech Connect

    Hooper, Dan; Serpico, Pasquale D.; /Fermilab

    2007-02-01

    Dark matter annihilating in our Galaxy's halo and elsewhere in the universe is expected to generate a diffuse flux of gamma rays, potentially observable with next generation satellite-based experiments, such as GLAST. In this article, we study the signatures of dark matter in the angular distribution of this radiation. Pertaining to the extragalactic contribution, we discuss the effect of the motion of the solar system with respect to the cosmological rest frame, and anisotropies due to the structure of our local universe. For the gamma ray flux from dark matter in our own Galactic halo, we discuss the effects of the offset position of the solar system, the Compton-Getting effect, the asphericity of the Milky Way halo, and the signatures of nearby substructure. We explore the prospects for the detection of these features by the GLAST satellite and find that, if {approx} 10% or more of the diffuse gamma ray background observed by EGRET is the result of dark matter annihilations, then GLAST should be sensitive to anisotropies down to the 0.1% level. Such precision would be sufficient to detect many, if not all, of the signatures discussed in this paper.

  16. Prompt gamma activation analysis of boron in reference materials using diffracted polychromatic neutron beam

    NASA Astrophysics Data System (ADS)

    Byun, S. H.; Sun, G. M.; Choi, H. D.

    2004-01-01

    Boron concentrations were analyzed for standard reference materials by prompt gamma activation analysis (PGAA). The measurements were performed at the SNU-KAERI PGAA facility installed at Hanaro, the research reactor of Korea Atomic Energy Research Institute (KAERI). The facility uses a diffracted polychromatic beam with a neutron flux of 7.9 × 10 7 n/cm 2 s. Elemental sensitivity for boron was calibrated from the prompt gamma-ray spectra of boric acid samples containing 2-45 μg boron. The sensitivity of 2131 cps/mg-B was obtained from the linearity of the boron peak count rate versus the boron mass. The detection limit for boron was estimated to be 67 ng from an empty sample bag spectrum for a counting time of 10,000 s. The measured boron concentrations for standard reference materials showed good consistency with the certified or information values.

  17. A pseudo-spectrum analysis of galaxy-galaxy lensing

    NASA Astrophysics Data System (ADS)

    Hikage, Chiaki; Oguri, Masamune

    2016-10-01

    We present the application of the pseudo-spectrum method to galaxy-galaxy lensing. We derive explicit expressions for the pseudo-spectrum analysis of the galaxy-shear cross-spectrum, which is the Fourier space counterpart of the stacked galaxy-galaxy lensing profile. The pseudo-spectrum method corrects observational issues such as the survey geometry, masks of bright stars and their spikes, and inhomogeneous noise, which distort the spectrum and also mix the E-mode and the B-mode signals. Using ray-tracing simulations in N-body simulations including realistic masks, we confirm that the pseudo-spectrum method successfully recovers the input galaxy-shear cross-spectrum. We also show that the galaxy-shear cross-spectrum has an excess covariance relative to the Gaussian covariance at small scales (k ≳ 1h Mpc-1) where the shot noise is dominated in the Gaussian approximation. We find that the excess is consistent with the expectation from the halo sample variance (HSV), which originates from the matter fluctuations at scales larger than the survey area. We apply the pseudo-spectrum method to the observational data of Canada-France-Hawaii Telescope Lensing survey shear catalogue and three different spectroscopic samples of Sloan Digital Sky Survey Luminous Red Galaxy, and Baryon Oscillation Spectroscopic Survey CMASS and LOWZ galaxies. The galaxy-shear cross-spectra are significantly detected at the level of 7-10σ using the analytic covariance with the HSV contribution included. We also confirm that the observed spectra are consistent with the halo model predictions with the halo occupation distribution parameters estimated from previous work. This work demonstrates the viability of galaxy-galaxy lensing analysis in the Fourier space.

  18. Modal combination in response spectrum modal dynamic analysis

    SciTech Connect

    Hammond, C.R.; Singhal, M.K.

    1993-09-01

    UCRL-15910 does not give explicit requirements for combining the values of the resonse of individual modes in a response spectrum modal dynamic analysis. Since UCRL-15910 references ASE 4-86, modal combination methods given in ASCE 4-86 are described in this paper. Efficient use of typical dynamic analysis computer programs while complying with ASCE 4-86 is also described.

  19. [The spectrum characteristic analysis of mammoth ivory].

    PubMed

    Yin, Zuo-wei; Luo, Qin-feng; Zheng, Chen; Bao, De-qing; Li, Xiao-lu; Li, Yu-ling; Chen, Quan-li

    2013-09-01

    Due to the similarities between mammoth ivory ornaments and modern elephant ivory ones in the market, the spectral properties of the two kinds of ivories were analyzed and compared in the present paper through the gemological tests, infrared spectrum and X-ray powder diffraction, etc. The research found that the refractive index and specific gravity of the two ivories are very similar. The refractive index of mammoth ivory is 1.52-1.53 whereas that of elephant ivory is 1.54-1.55. The specific gravity of mammoth ivory is 1.77 and that of elephant ivory is 1.72. It should be careful that Schreger angles are used to distinguish the two kinds of ivories, because the angles of inner and middle layers in the two kinds of tusks are similar except the angles of elephant tusk out-layers are larger than those of mammoth (The Schreger angle of the sample mammoth ivory belonging to out-layer tusks is 100 degrees nd that of elephant ivory is 115 degrees). In addition, the out-layer Schreger angles of Asian elephants are normally less than 120 degrees, while those of Africa elephants are bigger than 120 degrees (This can be used to identify Asian and Africa elephant ivories). The infrared spectroscopy test shows that the water-molecule-related absorption peaks of 3319, 1642 and 1557 cm(-1) are more obvious in the modern elephant ivory samples than in the mammoth ivory samples; the collagen-related absorption peaks of 2927and 2855 cm(-1) are obvious in the modern elephant ivory but extremely weak in the mammoth ivory. The results indicate that collagen and crystallized water in mammoth ivory reduced to a very low level after having been buried for a long period. X-ray powder diffraction results show that the diffraction peak splits of mammoth ivories are more obvious and sharp than that of elephant ivories, which means hydroxyapatites crystallized better despite being buried for thousands of years. Hence, it is an important reference for identifying the two kinds of ivories that

  20. [The spectrum characteristic analysis of mammoth ivory].

    PubMed

    Yin, Zuo-wei; Luo, Qin-feng; Zheng, Chen; Bao, De-qing; Li, Xiao-lu; Li, Yu-ling; Chen, Quan-li

    2013-09-01

    Due to the similarities between mammoth ivory ornaments and modern elephant ivory ones in the market, the spectral properties of the two kinds of ivories were analyzed and compared in the present paper through the gemological tests, infrared spectrum and X-ray powder diffraction, etc. The research found that the refractive index and specific gravity of the two ivories are very similar. The refractive index of mammoth ivory is 1.52-1.53 whereas that of elephant ivory is 1.54-1.55. The specific gravity of mammoth ivory is 1.77 and that of elephant ivory is 1.72. It should be careful that Schreger angles are used to distinguish the two kinds of ivories, because the angles of inner and middle layers in the two kinds of tusks are similar except the angles of elephant tusk out-layers are larger than those of mammoth (The Schreger angle of the sample mammoth ivory belonging to out-layer tusks is 100 degrees nd that of elephant ivory is 115 degrees). In addition, the out-layer Schreger angles of Asian elephants are normally less than 120 degrees, while those of Africa elephants are bigger than 120 degrees (This can be used to identify Asian and Africa elephant ivories). The infrared spectroscopy test shows that the water-molecule-related absorption peaks of 3319, 1642 and 1557 cm(-1) are more obvious in the modern elephant ivory samples than in the mammoth ivory samples; the collagen-related absorption peaks of 2927and 2855 cm(-1) are obvious in the modern elephant ivory but extremely weak in the mammoth ivory. The results indicate that collagen and crystallized water in mammoth ivory reduced to a very low level after having been buried for a long period. X-ray powder diffraction results show that the diffraction peak splits of mammoth ivories are more obvious and sharp than that of elephant ivories, which means hydroxyapatites crystallized better despite being buried for thousands of years. Hence, it is an important reference for identifying the two kinds of ivories that

  1. The Murchison Widefield Array 21 cm Power Spectrum Analysis Methodology

    NASA Astrophysics Data System (ADS)

    Jacobs, Daniel C.; Hazelton, B. J.; Trott, C. M.; Dillon, Joshua S.; Pindor, B.; Sullivan, I. S.; Pober, J. C.; Barry, N.; Beardsley, A. P.; Bernardi, G.; Bowman, Judd D.; Briggs, F.; Cappallo, R. J.; Carroll, P.; Corey, B. E.; de Oliveira-Costa, A.; Emrich, D.; Ewall-Wice, A.; Feng, L.; Gaensler, B. M.; Goeke, R.; Greenhill, L. J.; Hewitt, J. N.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kaplan, D. L.; Kasper, J. C.; Kim, HS; Kratzenberg, E.; Lenc, E.; Line, J.; Loeb, A.; Lonsdale, C. J.; Lynch, M. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Neben, A. R.; Thyagarajan, N.; Oberoi, D.; Offringa, A. R.; Ord, S. M.; Paul, S.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A. E. E.; Roshi, A.; Udaya Shankar, N.; Sethi, Shiv K.; Srivani, K. S.; Subrahmanyan, R.; Tegmark, M.; Tingay, S. J.; Waterson, M.; Wayth, R. B.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L.; Wu, C.; Wyithe, J. S. B.

    2016-07-01

    We present the 21 cm power spectrum analysis approach of the Murchison Widefield Array Epoch of Reionization project. In this paper, we compare the outputs of multiple pipelines for the purpose of validating statistical limits cosmological hydrogen at redshifts between 6 and 12. Multiple independent data calibration and reduction pipelines are used to make power spectrum limits on a fiducial night of data. Comparing the outputs of imaging and power spectrum stages highlights differences in calibration, foreground subtraction, and power spectrum calculation. The power spectra found using these different methods span a space defined by the various tradeoffs between speed, accuracy, and systematic control. Lessons learned from comparing the pipelines range from the algorithmic to the prosaically mundane; all demonstrate the many pitfalls of neglecting reproducibility. We briefly discuss the way these different methods attempt to handle the question of evaluating a significant detection in the presence of foregrounds.

  2. The Stellar X-ray Polarimeter - A focal plane polarimeter for the Spectrum X-Gamma mission

    NASA Technical Reports Server (NTRS)

    Kaaret, P.; Novick, R.; Martin, C.; Shaw, P.; Hamilton, T.; Suniaev, R.; Lapshov, I.; Silver, E.; Weisskopf, M.; Elsner, R.

    1990-01-01

    This paper describes an X-ray polarimeter that will be flown on the Spectrum X-Gamma mission. The instrument exploits three distinct physical processes to measure polarization: Bragg reflection from a graphite crystal, Thomson scattering from a metallic lithium target, and photoemission from a cesium iodide photocathode. These three methods allow polarization measurements over an energy band from 0.3 to 12 keV. The polarimeter will make possible sensitive measurements of several hundred known X-ray sources. X-ray polarization measurements will make it possible to constrain the geometry of gas flow in X-ray binaries, identify nonthermal emission in supernova remnants, test current models for X-ray emission in radio pulsars, determine the radiation mechanisms in active galactic nuclei, and search for inertial frame dragging (Lense-Thirring effect) around the putative black hole in Cygnus X-1.

  3. Predicted performance of the lithium scattering and graphite crystal polarimeter for the Spectrum-X-Gamma mission

    NASA Technical Reports Server (NTRS)

    Weisskopf, M. C.; Elsner, R. F.; Novick, R.; Kaaret, P.; Silver, E.

    1991-01-01

    X-ray scattering from a lithium disk and Bragg reflection from a mosaic graphite crystal can be exploited to measure the linear polarization of radiation emitted from cosmic X-ray sources. The sensitivity is greatly enhanced if these polarimeters are placed at the focus of an X-ray telescope. Such devices form two of the three components of the Stellar X-Ray Polarimeter experiment scheduled to fly on the Spectrum-X-Gamma mission. The experiment will reside at the focus of one of the SODART X-ray telescopes. The expected on-axis performance of these two components of the Stellar X-Ray Polarimeter experiment based on detailed Monte-Carlo simulation is described. Various systematic effects, both external and internal to the experiment, that must be considered in order to properly design and utilize the experiment are also discussed.

  4. The REFLEX II galaxy cluster survey: power spectrum analysis

    NASA Astrophysics Data System (ADS)

    Balaguera-Antolínez, A.; Sánchez, Ariel G.; Böhringer, H.; Collins, C.; Guzzo, L.; Phleps, S.

    2011-05-01

    We present the power spectrum of galaxy clusters measured from the new ROSAT-ESO Flux-Limited X-Ray (REFLEX II) galaxy cluster catalogue. This new sample extends the flux limit of the original REFLEX catalogue to 1.8 × 10-12 erg s-1 cm-2, yielding a total of 911 clusters with ≥94 per cent completeness in redshift follow-up. The analysis of the data is improved by creating a set of 100 REFLEX II-catalogue-like mock galaxy cluster catalogues built from a suite of large-volume Λ cold dark matter (ΛCDM) N-body simulations (L-BASICC II). The measured power spectrum is in agreement with the predictions from a ΛCDM cosmological model. The measurements show the expected increase in the amplitude of the power spectrum with increasing X-ray luminosity. On large scales, we show that the shape of the measured power spectrum is compatible with a scale-independent bias and provide a model for the amplitude that allows us to connect our measurements with a cosmological model. By implementing a luminosity-dependent power-spectrum estimator, we observe that the power spectrum measured from the REFLEX II sample is weakly affected by flux-selection effects. The shape of the measured power spectrum is compatible with a featureless power spectrum on scales k > 0.01 h Mpc-1 and hence no statistically significant signal of baryonic acoustic oscillations can be detected. We show that the measured REFLEX II power spectrum displays signatures of non-linear evolution.

  5. A comparative analysis of gamma and hadron families at the superhigh energies recorded in experiment Pamir

    NASA Technical Reports Server (NTRS)

    Azimov, S. A.; Mulladjanov, E. J.; Nosov, A. N.; Nuritdinov, H.; Talipov, D. A.; Halilov, D. A.; Yuldashbaev, T. S.

    1985-01-01

    A comparative analysis of hadron and gamma families which have undergone the decascading procedure is made. Results are compared with different models of interactions. In hadron families with energies Summary E sub H sup gamma 20 TeV as well as in gamma families with energies Summary E sub gamma 70 TeV, increasing azimuthal anisotropy is observed.

  6. Conservative constraints on dark matter from the Fermi-LAT isotropic diffuse gamma-ray background spectrum

    SciTech Connect

    Abazajian, Kevork N.; Agrawal, Prateek; Chacko, Zackaria; Kilic, Can E-mail: apr@umd.edu E-mail: kilic@physics.rutgers.edu

    2010-11-01

    We examine the constraints on final state radiation from Weakly Interacting Massive Particle (WIMP) dark matter candidates annihilating into various standard model final states, as imposed by the measurement of the isotropic diffuse gamma-ray background by the Large Area Telescope aboard the Fermi Gamma-Ray Space Telescope. The expected isotropic diffuse signal from dark matter annihilation has contributions from the local Milky Way (MW) as well as from extragalactic dark matter. The signal from the MW is very insensitive to the adopted dark matter profile of the halos, and dominates the signal from extragalactic halos, which is sensitive to the low mass cut-off of the halo mass function. We adopt a conservative model for both the low halo mass survival cut-off and the substructure boost factor of the Galactic and extragalactic components, and only consider the primary final state radiation. This provides robust constraints which reach the thermal production cross-section for low mass WIMPs annihilating into hadronic modes. We also reanalyze limits from HESS observations of the Galactic Ridge region using a conservative model for the dark matter halo profile. When combined with the HESS constraint, the isotropic diffuse spectrum rules out all interpretations of the PAMELA positron excess based on dark matter annihilation into two lepton final states. Annihilation into four leptons through new intermediate states, although constrained by the data, is not excluded.

  7. Producing the universal spectrum of cosmological gamma-ray bursts with the Klein-Nishina cross section

    NASA Technical Reports Server (NTRS)

    Brainerd, J. J.

    1994-01-01

    A power-law spectrum attenuated through Compton scattering by an optically thick medium produces spectra that have a characteristic energy of several hundred keV. Add a redshift, and one finds that this model can qualitatively reproduce the color-color diagrams found for individual gamma-ray bursts. This model is easily tested through model fits to burst spectra and through comparisons of the parameters derived from model fits to the limits on parameters derived from the burst log N - log P(sub max) curve. The heavy attenuation makes the amount of energy released in the burst approximately equal to 10(exp 3) times larger than is inferred from the observed flux. The requirements of high optical depth and no photon-photon pair creation place a lower limit on the size of the scattering region. This size suggests that the attenuation occurs in giant molecular clouds in the cores of galaxies. This indicates that gamma-ray bursts are probably from supermassive black holes. If the Lorentz factor of the radiation source is large, the optical depth, and therefore the hardness ratio of a burst, can change over the duration of the burst.

  8. Calculation of the spectrum of {gamma} rays connecting superdeformed and normally deformed nuclear states

    SciTech Connect

    Dossing, T.; Khoo, T.L.; Lauritsen, T.

    1995-08-01

    The decay out of superdeformed states occurs by coupling to compound nuclear states of normal deformation. The coupling is very weak, resulting in mixing of the SD state with one or two normal compound states. With a high energy available for decay, a statistical spectrum ensues. The shape of this statistical spectrum contains information on the level densities of the excited states below the SD level. The level densities are sensitively affected by the pair correlations. Thus decay-out of a SD state (which presents us with a means to start a statistical cascade from a highly-excited sharp state) provides a method for investigating the reduction of pairing with increasing thermal excitation energy.

  9. Prompt gamma analysis of chlorine in concrete for corrosion study.

    PubMed

    Naqvi, A A; Nagadi, M M; Al-Amoudi, O S B

    2006-02-01

    Measurement of chlorine in concrete is very important for studying of corrosion of reinforcing steel in concrete. Corrosion of reinforcing steel is primarily ascribed to the penetration of chloride ions to the steel surface. Preventive measures for avoiding concrete structure reinforcement corrosion requires monitoring the chloride ion concentration in concrete so that its concentration does not exceed a threshold limit to initiate reinforcement concrete corrosion. An accelerator based prompt gamma neutron activation analysis (PGNAA) setup has been developed for non-destructive analysis of elemental composition of concrete samples. The setup has been used to measure chlorine concentration in concrete samples over a 1-3 wt% concentration range. Although a strong interference has been observed between the chlorine gamma-rays and calcium gamma-rays from concrete, the chlorine concentration in concrete samples has been successfully measured using the 1.164 and 7.643 MeV chlorine gamma-rays. The experimental data were compared with the results of the Monte Carlo simulations. An excellent agreement has been achieved between the experimental data and results of Monte Carlo simulations. The study has demonstrated the successful use of the accelerator-based PGNAA setup in non-destructive analysis of chlorine in concrete samples. PMID:16129605

  10. GammaLib and ctools. A software framework for the analysis of astronomical gamma-ray data

    NASA Astrophysics Data System (ADS)

    Knödlseder, J.; Mayer, M.; Deil, C.; Cayrou, J.-B.; Owen, E.; Kelley-Hoskins, N.; Lu, C.-C.; Buehler, R.; Forest, F.; Louge, T.; Siejkowski, H.; Kosack, K.; Gerard, L.; Schulz, A.; Martin, P.; Sanchez, D.; Ohm, S.; Hassan, T.; Brau-Nogué, S.

    2016-08-01

    The field of gamma-ray astronomy has seen important progress during the last decade, yet to date no common software framework has been developed for the scientific analysis of gamma-ray telescope data. We propose to fill this gap by means of the GammaLib software, a generic library that we have developed to support the analysis of gamma-ray event data. GammaLib was written in C++ and all functionality is available in Python through an extension module. Based on this framework we have developed the ctools software package, a suite of software tools that enables flexible workflows to be built for the analysis of Imaging Air Cherenkov Telescope event data. The ctools are inspired by science analysis software available for existing high-energy astronomy instruments, and they follow the modular ftools model developed by the High Energy Astrophysics Science Archive Research Center. The ctools were written in Python and C++, and can be either used from the command line via shell scripts or directly from Python. In this paper we present the GammaLib and ctools software versions 1.0 that were released at the end of 2015. GammaLib and ctools are ready for the science analysis of Imaging Air Cherenkov Telescope event data, and also support the analysis of Fermi-LAT data and the exploitation of the COMPTEL legacy data archive. We propose using ctools as the science tools software for the Cherenkov Telescope Array Observatory.

  11. Spectrum and variation of gamma-ray emission from the galactic center region

    NASA Technical Reports Server (NTRS)

    Riegler, G. R.; Ling, J. C.; Mahoney, W. A.; Wheaton, W. A.; Jacobson, A. S.

    1982-01-01

    Continuum emission at 60-300 keV from the galactic center region was observed to decrease in intensity by 45 percent and to show a spectrum steepening between fall 1979 and spring 1980. At the same time 511 keV positron annihilation radiation decreased by a comparable fraction. No variations over shorter time scales were detected. The observations are consistent with a model where positrons and hard X-rays are produced in an electromagnetic cascade near a massive black hole.

  12. A dynamic spectrum analysis solution for the characterization of the UHF spectrum

    NASA Astrophysics Data System (ADS)

    Pooler, Richard K.; Narayanan, Ram M.; Sherbondy, Kelly D.; Martone, Anthony F.; Gallagher, Kyle A.

    2016-05-01

    The Spectral Analysis Solution (SAS), under development, is a multichannel superheterodyne signal analyzer with the intended applications of radio frequency (RF) research, radar verification, and general purpose spectrum sensing, primarily in the ultra-wideband (UWB) range from ultra high frequency (UHF) to the S-band. The SAS features a wideband channel operating from 100 kHz to 1.8 GHz and eight narrowband channels having adjustable instantaneous bandwidths ranging from 1 MHz to 100 MHz. The wideband channel provides a large picture of the RF spectrum while the narrowband channels allow for high resolution, low noise floor, and high spurious free dynamic range (SFDR) capabilities. An adaptive graphic user interface (GUI) has been implemented for the system that actively pulls and processes the system data in real time. This paper outlines the motivation and theory behind the system along with system validation and implementation results.

  13. Nuclear fuel microsphere gamma analyzer

    DOEpatents

    Valentine, Kenneth H.; Long, Jr., Ernest L.; Willey, Melvin G.

    1977-01-01

    A gamma analyzer system is provided for the analysis of nuclear fuel microspheres and other radioactive particles. The system consists of an analysis turntable with means for loading, in sequence, a plurality of stations within the turntable; a gamma ray detector for determining the spectrum of a sample in one section; means for analyzing the spectrum; and a receiver turntable to collect the analyzed material in stations according to the spectrum analysis. Accordingly, particles may be sorted according to their quality; e.g., fuel particles with fractured coatings may be separated from those that are not fractured, or according to other properties.

  14. Prompt Gamma-Ray Neutron Activation Analysis (PGNAA) for Elemental Analysis

    SciTech Connect

    Robin P. Gardner

    2006-04-11

    This research project was to improve the prompt gamma-ray neutron activation analysis (PGNAA) measurement approach for bulk analysis, oil well logging, and small sample thermal enutron bean applications.

  15. Spectrum of {gamma} rays from the decay of SD to normal states in {sup 191}Hg

    SciTech Connect

    Gassmann, D.; Khoo, T.L.; Lauritsen, T.

    1995-08-01

    In B.a.7. we propose that the statistical spectrum emitted from a sharp single excited state serves as a probe of pairing in excited states. A specific test of this proposal is the comparison of the spectra from even-even and odd-even nuclei. Whereas a pair gap exists in an even-even nucleus, it gets filled in an odd-even nucleus. Consequently, low-energy transitions can arise in the latter case, whereas they are calculated to be absent in the former case because very few levels exist in the cold gap region. In addition, transitions between 1.4 - 2.2 MeV, which {open_quotes}jump{close_quotes} across the gap, are predicted to have lower yield in the odd-even nuclei. Serendipitously, decay from a superdeformed state serves as a good initial excited sharp state. We extracted the spectrum pairwise-coincident with SD lines in {sup 191}Hg from Gammasphere data and compared it with the equivalent spectra from the even-even nuclei {sup 192,194}Hg. The differences that are predicted to occur are indeed observed. Thus, the data support our proposal that the reduction of pairing with thermal excitation energy can be probed with statistical decay spectra.

  16. Toward a fractal spectrum approach for neutron and gamma pulse shape discrimination

    NASA Astrophysics Data System (ADS)

    Liu, Ming-Zhe; Liu, Bing-Qi; Zuo, Zhuo; Wang, Lei; Zan, Gui-Bin; Tuo, Xian-Guo

    2016-06-01

    Accurately selecting neutron signals and discriminating γ signals from a mixed radiation field is a key research issue in neutron detection. This paper proposes a fractal spectrum discrimination approach by means of different spectral characteristics of neutrons and γ rays. Figure of merit and average discriminant error ratio are used together to evaluate the discrimination effects. Different neutron and γ signals with various noise and pulse pile-up are simulated according to real data in the literature. The proposed approach is compared with the digital charge integration and pulse gradient methods. It is found that the fractal approach exhibits the best discrimination performance, followed by the digital charge integration method and the pulse gradient method, respectively. The fractal spectrum approach is not sensitive to high frequency noise and pulse pile-up. This means that the proposed approach has superior performance for effective and efficient anti-noise and high discrimination in neutron detection. Supported by the National Natural Science Foundation of China (41274109), Sichuan Youth Science and Technology Innovation Research Team (2015TD0020), Scientific and Technological Support Program of Sichuan Province (2013FZ0022), and the Creative Team Program of Chengdu University of Technology.

  17. 2009 Autism Spectrum Disorder Research: Portfolio Analysis Report

    ERIC Educational Resources Information Center

    Interagency Autism Coordinating Committee, 2011

    2011-01-01

    In 2010, the Office of Autism Research Coordination (OARC) and Acclaro Research Solutions, Inc., on behalf of the Interagency Autism Coordinating Committee (IACC), conducted a comprehensive analysis of the 2009 autism spectrum disorder (ASD) research portfolio of major Federal agencies and private organizations. This is the second annual analysis…

  18. Analysis of data from the energetic gamma-ray experiment of the Gamma Ray Observatory

    NASA Technical Reports Server (NTRS)

    Kniffen, Donald A.

    1995-01-01

    The work under the Grant has involved continued participation with the Compton Gamma Ray Observatory Energetic Gamma-Ray Experiment Telescope (EGRET) Team in the analysis of data obtained during instrument operations and the preparation of scientific papers and proposals for future observations. The EGRET team continues to submit IAU Astronomical telegrams and present many papers at scientific meetings. The EGRET Team was also successful on many proposals for the Cycle 4 portion of the mission, including long high galactic latitude studies of the diffuse extragalactic radiation in both the Northern and Southern Galactic Sky. These studies will be used in an effort to establish whether this radiation is truly diffuse or the sum of radiation from unresolved discrete sources such as radio-loud quasars. Data analysis is complete for papers on behalf of the EGRET Team by the author on general sources in the anticenter region of the galaxy, with galactic latitudes from 125 to 220 deg. A paper on this subject is in preparation for publication in the Astrophysical Journal. Another is being prepared on EGRET observations of the COS-B source 2CG135. Work is in progress for a third on the contribution of unresolved pulsars to the galactic diffuse radiations; two other papers are in analysis phase. A number of papers have been published in the last reporting period, and several others are in press currently. A summary of the publications is described.

  19. A new approach to automatic radiation spectrum analysis

    SciTech Connect

    Olmos, P.; Diaz, J.C.; Perez, J.M.; Aguayo, P.; Bru, A.; Garcia-Belmonte, G.; de Pablos, J.L. ); Gomez, P.; Rodellar, V. )

    1991-08-01

    In this paper the application of adaptive methods to the solution of the automatic radioisotope identification problem using the energy spectrum is described. The identification is carried out by means of neural networks, which allow the use of relatively reduced computational structures, while keeping high pattern recognition capability. In this context, it has been found that one of these simple structures, once adequately trained, is quite suitable to identify a given isotope present in a mixture of elements as well as the relative proportions of each identified substance. Preliminary results are good enough to consider these adaptive structures as powerful and simple tools in the automatic spectrum analysis.

  20. [EMD Time-Frequency Analysis of Raman Spectrum and NIR].

    PubMed

    Zhao, Xiao-yu; Fang, Yi-ming; Tan, Feng; Tong, Liang; Zhai, Zhe

    2016-02-01

    This paper analyzes the Raman spectrum and Near Infrared Spectrum (NIR) with time-frequency method. The empirical mode decomposition spectrum becomes intrinsic mode functions, which the proportion calculation reveals the Raman spectral energy is uniform distributed in each component, while the NIR's low order intrinsic mode functions only undertakes fewer primary spectroscopic effective information. Both the real spectrum and numerical experiments show that the empirical mode decomposition (EMD) regard Raman spectrum as the amplitude-modulated signal, which possessed with high frequency adsorption property; and EMD regards NIR as the frequency-modulated signal, which could be preferably realized high frequency narrow-band demodulation during first-order intrinsic mode functions. The first-order intrinsic mode functions Hilbert transform reveals that during the period of empirical mode decomposes Raman spectrum, modal aliasing happened. Through further analysis of corn leaf's NIR in time-frequency domain, after EMD, the first and second orders components of low energy are cut off, and reconstruct spectral signal by using the remaining intrinsic mode functions, the root-mean-square error is 1.001 1, and the correlation coefficient is 0.981 3, both of these two indexes indicated higher accuracy in re-construction; the decomposition trend term indicates the absorbency is ascending along with the decreasing to wave length in the near-infrared light wave band; and the Hilbert transform of characteristic modal component displays, 657 cm⁻¹ is the specific frequency by the corn leaf stress spectrum, which could be regarded as characteristic frequency for identification. PMID:27209743

  1. [EMD Time-Frequency Analysis of Raman Spectrum and NIR].

    PubMed

    Zhao, Xiao-yu; Fang, Yi-ming; Tan, Feng; Tong, Liang; Zhai, Zhe

    2016-02-01

    This paper analyzes the Raman spectrum and Near Infrared Spectrum (NIR) with time-frequency method. The empirical mode decomposition spectrum becomes intrinsic mode functions, which the proportion calculation reveals the Raman spectral energy is uniform distributed in each component, while the NIR's low order intrinsic mode functions only undertakes fewer primary spectroscopic effective information. Both the real spectrum and numerical experiments show that the empirical mode decomposition (EMD) regard Raman spectrum as the amplitude-modulated signal, which possessed with high frequency adsorption property; and EMD regards NIR as the frequency-modulated signal, which could be preferably realized high frequency narrow-band demodulation during first-order intrinsic mode functions. The first-order intrinsic mode functions Hilbert transform reveals that during the period of empirical mode decomposes Raman spectrum, modal aliasing happened. Through further analysis of corn leaf's NIR in time-frequency domain, after EMD, the first and second orders components of low energy are cut off, and reconstruct spectral signal by using the remaining intrinsic mode functions, the root-mean-square error is 1.001 1, and the correlation coefficient is 0.981 3, both of these two indexes indicated higher accuracy in re-construction; the decomposition trend term indicates the absorbency is ascending along with the decreasing to wave length in the near-infrared light wave band; and the Hilbert transform of characteristic modal component displays, 657 cm⁻¹ is the specific frequency by the corn leaf stress spectrum, which could be regarded as characteristic frequency for identification.

  2. Advanced gamma ray balloon experiment ground checkout and data analysis

    NASA Technical Reports Server (NTRS)

    Blackstone, M.

    1976-01-01

    A software programming package to be used in the ground checkout and handling of data from the advanced gamma ray balloon experiment is described. The Operator's Manual permits someone unfamiliar with the inner workings of the software system (called LEO) to operate on the experimental data as it comes from the Pulse Code Modulation interface, converting it to a form for later analysis, and monitoring the program of an experiment. A Programmer's Manual is included.

  3. Analyses of Oxyanion Materials by Prompt Gamma Activation Analysis

    SciTech Connect

    Firestone, Richard B; Perry, D.L.; English, G.A.; Firestone, R.B.; Leung, K.-N.; Garabedian, G.; Molnar, G.L.; Revay, Zs.

    2008-03-24

    Prompt gamma activation analysis (PGAA) has been used to analyze metal ion oxyanion materials that have multiple applications, including medicine, materials, catalysts, and electronics. The significance for the need for accurate, highly sensitive analyses for the materials is discussed in the context of quality control of end products containing the parent element in each material. Applications of the analytical data for input to models and theoretical calculations related to the electronic and other properties of the materials are discussed.

  4. Analysis of data from the energetic gamma-ray experiment on the gamma ray observatory

    NASA Technical Reports Server (NTRS)

    Kniffen, Donald A.

    1993-01-01

    The work under the Grant has involved continued participation with the Compton Gamma Ray Observatory Energetic Gamma-Ray Experiment Telescope (EGRET) Team in the analysis of data obtained during instrument operations and the preparation of scientific papers and proposals for future observations. The EGRET team was also successful on many proposals for the Phase 3 portion of the mission, including long high galactic latitude studies of the diffuse extragalactic radiation. These studies will be used in a effort to establish whether this radiation is truly diffuse or the sum of radiation from unresolved discrete sources such as radio-loud quasars. The effort involved working remotely by internet connection on the Goddard Space Flight Center Computers where the EGRET data are archived. Students have monitored instrument performance and analyzed data remotely and will continue to do so. The PI has completed the detailed analysis of five viewing periods to search for point sources and this work has been used in developing the first EGRET catalog of sources, soon to be released.

  5. Analysis of Data from the Energetic Gamma-ray Experiment on the Gamma Ray Observatory

    NASA Technical Reports Server (NTRS)

    Kniffen, Donald A.

    1996-01-01

    The work under the Grant has involved participation with the Compton Gamma Ray Observatory Energetic Gamma-Ray Experiment Telescope (EGRET) Team in the analysis of data obtained during instrument operations and the preparation of scientific papers and proposals for future observations. The Principal Investigator (PI) has been a co-author on a total of 90 papers published in refereed professional journals since the beginning of 1991, plus many other non-refereed publications, and contributed and invited papers at professional meetings and IAU telegrams. On seven of these papers he was the lead author. The EGRET team continues to submit IAU Astronomical telegrams and present many papers at scientific meetings. The effort by the PI has involved working remotely by internet connection on the Goddard Space Flight Center Computers where the EGRET data are archived. Students have monitored instrument performance, performed Viewing Period Analyses and analyzed data remotely. The PI has completed the detailed analysis of over 20 viewing periods to search for point sources and this work has been used in developing the first and second EGRET catalog of sources, published in Supplements to the Astrophysical Journal.

  6. Lunar elemental analysis obtained from the Apollo gamma-ray and X-ray remote sensing experiment

    NASA Technical Reports Server (NTRS)

    Trombka, J. I.; Arnold, J. R.; Adler, I.; Metzger, A. E.; Reedy, R. C.

    1974-01-01

    Gamma ray and X-ray spectrometers carried in the service module of the Apollo 15 and 16 spacecraft were employed for compositional mapping of the lunar surface. The measurements involved the observation of the intensity and characteristics energy distribution of gamma rays and X-rays emitted from the lunar surface. A large scale compositional map of over 10 percent of the lunar surface was obtained from an analysis of the observed spectra. The objective of the X-ray experiment was to measure the K spectral lines from Mg, Al, and Si. Spectra were obtained and the data were reduced to Al/Si and Mg/Si intensity ratios and ultimately to chemical ratios. The objective of the gamma-ray experiment was to measure the natural and cosmic ray induced activity emission spectrum. At this time, the elemental abundances for Th, U, K, Fe, Ti, Si, and O have been determined over a number of major lunar regions.

  7. Spectral saliency via automatic adaptive amplitude spectrum analysis

    NASA Astrophysics Data System (ADS)

    Wang, Xiaodong; Dai, Jialun; Zhu, Yafei; Zheng, Haiyong; Qiao, Xiaoyan

    2016-03-01

    Suppressing nonsalient patterns by smoothing the amplitude spectrum at an appropriate scale has been shown to effectively detect the visual saliency in the frequency domain. Different filter scales are required for different types of salient objects. We observe that the optimal scale for smoothing amplitude spectrum shares a specific relation with the size of the salient region. Based on this observation and the bottom-up saliency detection characterized by spectrum scale-space analysis for natural images, we propose to detect visual saliency, especially with salient objects of different sizes and locations via automatic adaptive amplitude spectrum analysis. We not only provide a new criterion for automatic optimal scale selection but also reserve the saliency maps corresponding to different salient objects with meaningful saliency information by adaptive weighted combination. The performance of quantitative and qualitative comparisons is evaluated by three different kinds of metrics on the four most widely used datasets and one up-to-date large-scale dataset. The experimental results validate that our method outperforms the existing state-of-the-art saliency models for predicting human eye fixations in terms of accuracy and robustness.

  8. Study of the gamma-ray spectrum from the Galactic Center in view of multi-TeV dark matter candidates

    NASA Astrophysics Data System (ADS)

    Belikov, Alexander V.; Zaharijas, Gabrijela; Silk, Joseph

    2012-10-01

    Motivated by the complex gamma-ray spectrum of the Galactic Center source now measured over five decades in energy, we revisit the issue of the role of dark matter (DM) annihilations in this interesting region. We reassess whether the emission measured by the HESS collaboration could be a signature of dark matter annihilation, and we use the Fermi LAT spectrum to model the emission from SgrA*, using power-law spectral fits. We find that good fits are achieved by a power law with an index ˜2.5-2.6, in combination with a spectrum similar to the one observed from pulsar population and with a spectrum from a ≳10TeV DM annihilating to a mixture of bb¯ and harder τ+τ- channels and with boost factors of the order of a hundred. Alternatively, we also consider the combination of a log-parabola fit with the DM contribution. Finally, as both the spectrum of gamma rays from the Galactic Center and the spectrum of cosmic ray electrons exhibit a cutoff at TeV energies, we study the dark matter fits to both data sets. Constraining the spectral shape of the purported dark matter signal provides a robust way of comparing data. We find a marginal overlap only between the 99.999% C.L. regions in parameter space.

  9. Scintillation gamma spectrometer for analysis of hydraulic fracturing waste products.

    PubMed

    Ying, Leong; O'Connor, Frank; Stolz, John F

    2015-01-01

    Flowback and produced wastewaters from unconventional hydraulic fracturing during oil and gas explorations typically brings to the surface Naturally Occurring Radioactive Materials (NORM), predominantly radioisotopes from the U238 and Th232 decay chains. Traditionally, radiological sampling are performed by sending collected small samples for laboratory tests either by radiochemical analysis or measurements by a high-resolution High-Purity Germanium (HPGe) gamma spectrometer. One of the main isotopes of concern is Ra226 which requires an extended 21-days quantification period to allow for full secular equilibrium to be established for the alpha counting of its progeny daughter Rn222. Field trials of a sodium iodide (NaI) scintillation detector offers a more economic solution for rapid screenings of radiological samples. To achieve the quantification accuracy, this gamma spectrometer must be efficiency calibrated with known standard sources prior to field deployments to analyze the radioactivity concentrations in hydraulic fracturing waste products. PMID:25734826

  10. Analysis of Phobos mission gamma ray spectra from Mars

    NASA Technical Reports Server (NTRS)

    Trombka, J. I.; Evans, L. G.; Starr, R.; Floyd, S. R.; Squyres, S. W.; Whelan, J. T.; Bamford, G. J.; Coldwell, R. L.; Rester, A. C.; Surkov, Iu. A.

    1992-01-01

    The determination of the elemental composition of the surface of a planetary body can be achieved, in many cases, by remote-sensing gamma ray spectroscopy. A gamma ray spectrometer was carried on the Soviet spacecraft Phobos-2, and obtained data while in an elliptical orbit around Mars. Results of two independent approaches to data analysis, one by the Soviet group and one by an American group are reported. The results for five elements are given for two different orbits of Mars. Major geologic units that contribute to the signal for each orbit have been identified. The results from the two techniques are in general agreement and there appear to be no geologically significant differences between the results for each orbit.

  11. Fermi LAT detection of renewed GeV gamma-ray activity associated with the flat-spectrum radio source PKS 2247-131

    NASA Astrophysics Data System (ADS)

    Gasparrini, D.

    2016-10-01

    The Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope, has observed a renewed strong gamma-ray activity from a source positionally consistent with the flat-spectrum radio source PKS 2247-131 with coordinates RA=342.4983854 deg, Dec=-12.8546736 deg (J2000; Beasley et al. 2002, ApJS, 141, 13). Fermi-LAT already reported a flare on ATel #9285 but this source is not in any published LAT catalog and was not detected by AGILE or EGRET.

  12. Fermi-LAT detection of hard spectrum and high-level gamma-ray flare from the blazar PKS 1954-388

    NASA Astrophysics Data System (ADS)

    Cutini, Sara; Ciprini, Stefano; Fermi Large Area Telescope Collaboration

    2015-09-01

    The Large Area Telescope (LAT), one of two instruments on the Fermi Gamma-ray Space Telescope, has observed flaring gamma rays from a source positionally consistent with the flat spectrum radio quasar PKS 1954-388 (also known as MRC 1954-388, RX J1958.0-3845, and 3FGL J1958.0-3847, Acero et al. 2015, ApJS 218, 23), with radio coordinates, (J2000.0), R.A.: 299.499247 deg, Dec.: -38.751766 deg, (Ma et. al. 1998, AJ, 116, 516).

  13. Fermi-LAT detection of hard spectrum and highest-level gamma-ray outburst from the distant blazar PKS 1502+106

    NASA Astrophysics Data System (ADS)

    Ciprini, Stefano; Fermi Large Area Telescope Collaboration

    2015-07-01

    The Large Area Telescope (LAT), one of two instruments on the Fermi Gamma-ray Space Telescope, has observed flaring gamma rays from a source positionally consistent with the flat spectrum radio quasar PKS 1502+106 (also known as OR 103, S3 1502+10 and 3FGL J1504.4+1029, Acero et al. 2015, ApJS 218, 23), with radio coordinates, (J2000.0), R.A.: 226.10408 deg, Dec: 10.49422 deg (Johnston et al. 1995, AJ, 110, 880). This blazar has a redshift of z=1.8383 (Hewett & Wild 2010, MNRAS, 405, 2302).

  14. Fermi-LAT Detection of a Hard Spectrum and Enhanced Gamma-ray Emission from the Blazar PMN J2052-5533

    NASA Astrophysics Data System (ADS)

    Carpenter, Bryce; Magill, Jeff; Ojha, Roopesh

    2015-09-01

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope has observed an unusually hard spectrum gamma-ray flare from a source positionally consistent with the blazar PMN J2052-5533 (3FGL J2051.8-5535; Acero et al. 2015, ApJS 218, 23), with coordinates RA: 20h52m13.68s, Dec: -55d33m10.0s, J2000, (Healey et al. 2007, ApJS, 171, 61). There is no redshift reported for this source in the literature.

  15. Spectrum of atmospheric gamma rays to 10 MeV at lambda = 40 deg. [as function of altitude

    NASA Technical Reports Server (NTRS)

    Peterson, L. E.; Schwartz, D. A.; Ling, J. C.

    1973-01-01

    Results of measurements of the differential counting rate spectra due to atmospheric gamma rays as a function of altitude to 3.6 g/sq cm over Texas. Two gain settings and a 128-channel pulse height analyzer were used to cover the range from 0.2 to 10 MeV. The detector was a 7.6 x 7.6 cm NaI crystal, which was surrounded on five sides by a 2-cm-thick plastic anticoincidence shield for charged particle rejection. The system had a nearly isotropic response to photons above 0.2 MeV. The spectrum at ceiling appeared as a steep continuum with a power-law index of about 1.4. The only obvious feature was the 0.51-MeV positron annihilation line. The spectral shape was independent for depths less than 20 g/sq cm, the absolute intensity varying in proportion to the intensity of the cosmic ray secondary charged particles. Also, at depths less than 30 g/sq cm the observed flux variation with altitude can be described in terms of an empirical depth-dependent source function.

  16. Development of Mirror Modules for the ART-XC Instrument aboard the Spectrum-Roentgen-Gamma Mission

    NASA Technical Reports Server (NTRS)

    Gubarev, M; Ramsey, B.; O'Dell, S. L.; Elsner, R.; Kilaru, K.; McCracken, J.; Pavlinsky, M.; Tkachenko, A.; Lapshov, I.; Atkins, C.; Zavlin, V.

    2013-01-01

    The Marshall Space Flight Center (MSFC) is developing x-ray mirror modules for the ART-XC instrument on board the Spectrum-Roentgen Gamma Mission. Four of those modules are being fabricated under a Reimbursable Agreement between NASA and the Russian Space Research Institute (IKI.) An additional three flight modules and one spare for the ART-XC Instrument are produced under a Cooperative Agreement between NASA and IKI. The instrument will consist of seven co-aligned x-ray mirror modules with seven corresponding CdTe focal plane detectors. Each module consists of 28 nested thin Ni/Co shells giving an effective area of 65 cm2 at 8 keV, response out to 30 keV, and an angular resolution of 45 arcsec or better HPD. Delivery of the first four modules is scheduled for November 2013, while the remaining three modules will be delivered to IKI in January 2014. We present a status of the ART x-ray module development at MSFC.

  17. Time variations of an absorption feature in the spectrum of the gamma-ray burst on 1980 April 19

    NASA Technical Reports Server (NTRS)

    Dennis, B. R.; Frost, K. J.; Kiplinger, A. L.; Orwig, L. E.; Desai, U.; Cline, T. L.

    1982-01-01

    The photon number spectrum integrated over the impulsive part of the event is shown to fit a thermal bremsstrahlung function with a temperature of 330 + or - 70 keV at energies between 151 and 487 keV. At lower energies, the data points lie considerably below this function, indicating a broad absorption feature extending down to values less than or equal to 28 keV, the lowest energy measured. The upper energy of this absorption feature varies from 100 to 150 keV on a time scale less than or equal to 0.5 s. This event is interpreted as a typical gamma ray burst, even though it is still considered remotely possible that it is of solar origin. The spectral features, together with their variability, are interpreted in terms of electron interactions at the cyclotron resonance frequency in magnetic fields of 10 to the 12th - 10 to the 13th gauss close to the surface of a neutron star.

  18. [Research of Identify Spatial Object Using Spectrum Analysis Technique].

    PubMed

    Song, Wei; Feng, Shi-qi; Shi, Jing; Xu, Rong; Wang, Gong-chang; Li, Bin-yu; Liu, Yu; Li, Shuang; Cao Rui; Cai, Hong-xing; Zhang, Xi-he; Tan, Yong

    2015-06-01

    The high precision scattering spectrum of spatial fragment with the minimum brightness of 4.2 and the resolution of 0.5 nm has been observed using spectrum detection technology on the ground. The obvious differences for different types of objects are obtained by the normalizing and discrete rate analysis of the spectral data. Each of normalized multi-frame scattering spectral line shape for rocket debris is identical. However, that is different for lapsed satellites. The discrete rate of the single frame spectrum of normalized space debris for rocket debris ranges from 0.978% to 3.067%, and the difference of oscillation and average value is small. The discrete rate for lapsed satellites ranges from 3.118 4% to 19.472 7%, and the difference of oscillation and average value relatively large. The reason is that the composition of rocket debris is single, while that of the lapsed satellites is complex. Therefore, the spectrum detection technology on the ground can be used to the classification of the spatial fragment.

  19. Spectrum Gamma Ray bore hole logging while tripping with the sea floor drill rig MARUM-MeBo

    NASA Astrophysics Data System (ADS)

    Freudenthal, Tim; Steinke, Stephan; Mohtadi, Mahyar; Hebbeln, Dierk; Wefer, Gerold

    2013-04-01

    The robotic Sea Floor Drill Rig MARUM-MeBo developed at the MARUM Center for Marine Environmental Sciences at the University of Bremen was used to retrieve long sediment cores at two sites in the northern South China Sea. Both sites are located in about 1000 m water depth in southeasterly and southwesterly direction of the Pearl River mouth, respectively. South East Asian Monsoon variability controls terrigenous material transport by rivers into the South China Sea. The Pearl River is one of the largest rivers of the region that discharges into the northern South China Sea. The terrigenous fraction of marine sediments of the northern South China Sea therefore provides an excellent archive for reconstructing past variability of the South East Asian Monsoon system. In analogy to the drilling strategy within the Integrated Ocean Drilling Program IODP multiple holes were drilled in order to generate continuous spliced records at both sites. Overall the MARUM-MeBo drilled 374 m during 5 deployments with a maximum drilling depth of 80.85 m and an average core recovery of 94 %. Here we present first results of bore hole logging conducted during 4 of the 5 deployments with a spectrum gamma ray (SGR) probe adapted for the use with MARUM-MeBo. This probe is an autonomous slim hole probe that is used in the logging while tripping mode. This method is especially favorable for remote controlled drilling and logging operation. The probe is equipped with its own energy source and data storage. The probe is lowered into the drill string after the target wire-line coring depth is reached and after the last inner core barrel has been retrieved. When the probe has landed on the shoulder ring at the bottom of the hole, the drill string is pulled out and disassembled. The probe, while being raised with the drill string, continuously measures the geophysical properties of the in situ sediments and rocks. Since the bore hole is stabilized during the tripping process by the drill string

  20. Gamma-Ray background spectrum and annihilation rate in the baryon-symmetric big-bang cosmology

    NASA Technical Reports Server (NTRS)

    Puget, J. L.

    1973-01-01

    An attempt was made to extract experimental data on baryon symmetry by observing annihilation products. Specifically, gamma rays and neutrons with long mean free paths were analyzed. Data cover absorption cross sections and radiation background of the 0.511 MeV gamma rays from positron annihilations and the 70 MeV gamma rays from neutral pion decay.

  1. Condensing Raman spectrum for single-cell phenotype analysis

    PubMed Central

    2015-01-01

    Background In recent years, high throughput and non-invasive Raman spectrometry technique has matured as an effective approach to identification of individual cells by species, even in complex, mixed populations. Raman profiling is an appealing optical microscopic method to achieve this. To fully utilize Raman proling for single-cell analysis, an extensive understanding of Raman spectra is necessary to answer questions such as which filtering methodologies are effective for pre-processing of Raman spectra, what strains can be distinguished by Raman spectra, and what features serve best as Raman-based biomarkers for single-cells, etc. Results In this work, we have proposed an approach called rDisc to discretize the original Raman spectrum into only a few (usually less than 20) representative peaks (Raman shifts). The approach has advantages in removing noises, and condensing the original spectrum. In particular, effective signal processing procedures were designed to eliminate noise, utilising wavelet transform denoising, baseline correction, and signal normalization. In the discretizing process, representative peaks were selected to signicantly decrease the Raman data size. More importantly, the selected peaks are chosen as suitable to serve as key biological markers to differentiate species and other cellular features. Additionally, the classication performance of discretized spectra was found to be comparable to full spectrum having more than 1000 Raman shifts. Overall, the discretized spectrum needs about 5storage space of a full spectrum and the processing speed is considerably faster. This makes rDisc clearly superior to other methods for single-cell classication. PMID:26681607

  2. Multivariate statistical analysis of low-voltage EDS spectrum images

    SciTech Connect

    Anderson, I.M.

    1998-03-01

    Whereas energy-dispersive X-ray spectrometry (EDS) has been used for compositional analysis in the scanning electron microscope for 30 years, the benefits of using low operating voltages for such analyses have been explored only during the last few years. This paper couples low-voltage EDS with two other emerging areas of characterization: spectrum imaging and multivariate statistical analysis. The specimen analyzed for this study was a finished Intel Pentium processor, with the polyimide protective coating stripped off to expose the final active layers.

  3. Ultrasonic spectrum analysis using frequency-tracked gated RF pulses

    NASA Technical Reports Server (NTRS)

    Cantrell, J. H., Jr.; Heyman, J. S.

    1980-01-01

    A new method of ultrasonic frequency analysis is introduced which employs frequency-tracked gated RF drive pulses rather than shock-excited broadband spikes to generate the ultrasonic waveform. The new technique, a variation of the sampled-continuous wave technique, eliminates problems associated with finite pulse widths of conventional methods. It is shown to yield correct ultrasonic wave velocity measurements of the sample irrespective of receiver gate width or position provided any portions of two successive echoes are gated simultaneously into the spectrum analyzer. The experimental observations are substantiated by a theoretical model based on the time-frequency domain formulation of ultrasonic frequency analysis.

  4. Inferred Cosmic-Ray Spectrum from Fermi-LAT Gamma-Ray Observations of the Earths Limb

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Albert, A.; Allafort, A.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Blandford, R. D.; Brandt, T. J.; Hewitt, J.W.; Perkins, J. S.; Thompson, D. J.

    2014-01-01

    Recent accurate measurements of cosmic-ray (CR) species by ATIC-2, CREAM, and PAMELA reveal an unexpected hardening in the proton and He spectra above a few hundred GeV, a gradual softening of the spectra just below a few hundred GeV, and a harder spectrum of He compared to that of protons. These newly-discovered features may offer a clue to the origin of high-energy CRs. We use the Fermi Large Area Telescope observations of the -ray emission from the Earth's limb for an indirect measurement of the local spectrum of CR protons in the energy range approx. 90 GeV-6 TeV (derived from a photon energy range 15 GeV-1 TeV). Our analysis shows that single power law and broken power law spectra fit the data equally well and yield a proton spectrum with index 2.68 +/- 0.04 and 2.61 +/- 0.08 above approx. 200 GeV, respectively.

  5. DMD mutation spectrum analysis in 613 Chinese patients with dystrophinopathy.

    PubMed

    Guo, Ruolan; Zhu, Guosheng; Zhu, Huimin; Ma, Ruiyu; Peng, Ying; Liang, Desheng; Wu, Lingqian

    2015-08-01

    Dystrophinopathy is a group of inherited diseases caused by mutations in the DMD gene. Within the dystrophinopathy spectrum, Duchenne and Becker muscular dystrophies are common X-linked recessive disorders that mainly feature striated muscle necrosis. We combined multiplex ligation-dependent probe amplification with Sanger sequencing to detect large deletions/duplications and point mutations in the DMD gene in 613 Chinese patients. A total of 571 (93.1%) patients were diagnosed, including 428 (69.8%) with large deletions/duplications and 143 (23.3%) with point mutations. Deletion/duplication breakpoints gathered mostly in introns 44-55. Reading frame rules could explain 88.6% of deletion mutations. We identified seventy novel point mutations that had not been previously reported. Spectrum expansion and genotype-phenotype analysis of DMD mutations on such a large sample size in Han Chinese population would provide new insights into the pathogenic mechanism underlying dystrophinopathies.

  6. Reanalysis of the Apollo cosmic gamma-ray spectrum in the 0.3 to 10 MeV energy region

    NASA Technical Reports Server (NTRS)

    Dyer, C. S.; Trombka, J. I.; Evans, L. G.; Bielefeld, M. J.; Selzer, S. M.; Metzger, A. E.

    1977-01-01

    Additional data obtained from the Apollo 16 and 17 missions, together with collateral calculations on background radiation effects, have made possible an improved subtraction of unwanted backgrounds from the diffuse cosmic gamma ray data previously reported from Apollo 15. As a result, the 1 to 10 MeV spectrum is lowered significantly and connects smoothly with recent data at other energies. The inflection reported previously is much less pronounced and has no more than 1.5 sigma significance. Sky occultation by the Apollo 16 spacecraft shows the bulk of the 0.3 to 1 MeV radiation to be diffuse. The analysis of spurious backgrounds points to important improvements for future experiments designed for this spectral region. A light-weight satellite design can give a fourfold improvement in the signal to noise for such a measurement. Use of an anisotropic central crystal, which spins quickly compared with possible time variations in detector background, would enable sensitive limits to be set on galactic plane and point source contributions.

  7. Mixed Spectrum Analysis on fMRI Time-Series.

    PubMed

    Kumar, Arun; Lin, Feng; Rajapakse, Jagath C

    2016-06-01

    Temporal autocorrelation present in functional magnetic resonance image (fMRI) data poses challenges to its analysis. The existing approaches handling autocorrelation in fMRI time-series often presume a specific model of autocorrelation such as an auto-regressive model. The main limitation here is that the correlation structure of voxels is generally unknown and varies in different brain regions because of different levels of neurogenic noises and pulsatile effects. Enforcing a universal model on all brain regions leads to bias and loss of efficiency in the analysis. In this paper, we propose the mixed spectrum analysis of the voxel time-series to separate the discrete component corresponding to input stimuli and the continuous component carrying temporal autocorrelation. A mixed spectral analysis technique based on M-spectral estimator is proposed, which effectively removes autocorrelation effects from voxel time-series and identify significant peaks of the spectrum. As the proposed method does not assume any prior model for the autocorrelation effect in voxel time-series, varying correlation structure among the brain regions does not affect its performance. We have modified the standard M-spectral method for an application on a spatial set of time-series by incorporating the contextual information related to the continuous spectrum of neighborhood voxels, thus reducing considerably the computation cost. Likelihood of the activation is predicted by comparing the amplitude of discrete component at stimulus frequency of voxels across the brain by using normal distribution and modeling spatial correlations among the likelihood with a conditional random field. We also demonstrate the application of the proposed method in detecting other desired frequencies.

  8. The Spectrum of LSST Data Analysis Challenges: Kiloscale to Petascale

    NASA Astrophysics Data System (ADS)

    Loredo, Thomas J.; Babu, G. J.; Borne, K. D.; Feigelson, E. D.; Gray, A. G.; Informatics, LSST; Statistics Science Collaboration proposed

    2010-01-01

    The unprecedented science opportunities enabled by LSST's wide-fast-deep mode of operation are accompanied by equally unprecedented data analysis challenges, due to the huge size and synoptic scope of LSST data products. While the most obvious challenges are those due to the petabyte scale of fundamental LSST databases, new and difficult data analysis problems that span a broad range of sizes, types, and complexity, and require a matching breadth of methodological research, must also be addressed. Some smaller-scale LSST data products, such as multicolor light curves for individual objects, will present challenging statistics problems; e.g., requiring multivariate time series methods capable of handling nonuniform, non-simultaneous sampling with measurement errors. Very large-scale LSST data products, such as comprehensive catalogs of stars or galaxies, will require significant informatics/data mining innovation; e.g., to enable accurate classification or photo-z estimation for huge samples. These scales mark the boundaries of a broad spectrum of LSST data analysis problems; research-level informatics and statistics challenges arise in various combinations across this whole spectrum. We survey the diversity of forthcoming LSST data analysis problems and opportunities, highlighting representative problems that address compelling astronomical science and present significant methodological challenges involving both astrostatistics and astroinformatics.

  9. Statistical analysis of low-voltage EDS spectrum images

    SciTech Connect

    Anderson, I.M.

    1998-03-01

    The benefits of using low ({le}5 kV) operating voltages for energy-dispersive X-ray spectrometry (EDS) of bulk specimens have been explored only during the last few years. This paper couples low-voltage EDS with two other emerging areas of characterization: spectrum imaging of a computer chip manufactured by a major semiconductor company. Data acquisition was performed with a Philips XL30-FEG SEM operated at 4 kV and equipped with an Oxford super-ATW detector and XP3 pulse processor. The specimen was normal to the electron beam and the take-off angle for acquisition was 35{degree}. The microscope was operated with a 150 {micro}m diameter final aperture at spot size 3, which yielded an X-ray count rate of {approximately}2,000 s{sup {minus}1}. EDS spectrum images were acquired as Adobe Photoshop files with the 4pi plug-in module. (The spectrum images could also be stored as NIH Image files, but the raw data are automatically rescaled as maximum-contrast (0--255) 8-bit TIFF images -- even at 16-bit resolution -- which poses an inconvenience for quantitative analysis.) The 4pi plug-in module is designed for EDS X-ray mapping and allows simultaneous acquisition of maps from 48 elements plus an SEM image. The spectrum image was acquired by re-defining the energy intervals of 48 elements to form a series of contiguous 20 eV windows from 1.25 kV to 2.19 kV. A spectrum image of 450 x 344 pixels was acquired from the specimen with a sampling density of 50 nm/pixel and a dwell time of 0.25 live seconds per pixel, for a total acquisition time of {approximately}14 h. The binary data files were imported into Mathematica for analysis with software developed by the author at Oak Ridge National Laboratory. A 400 x 300 pixel section of the original image was analyzed. MSA required {approximately}185 Mbytes of memory and {approximately}18 h of CPU time on a 300 MHz Power Macintosh 9600.

  10. Fractal Spectrum Technique for Quantitative Analysis of Volcanic Particle Shapes

    NASA Astrophysics Data System (ADS)

    Maria, A. H.; Carey, S. N.

    2001-12-01

    The shapes of volcanic particles reflect numerous eruptive parameters (e.g. magma viscosity, volatile content, degree of interaction with water) and are useful for understanding fragmentation and transport processes associated with volcanic eruptions. However, quantitative analysis of volcanic particle shapes has proven difficult due to their morphological complexity and variability. Shape analysis based on fractal geometry has been successfully applied to a wide variety of particles and appears to be well suited for describing complex features. The technique developed and applied to volcanic particles in this study uses fractal data produced by dilation of the 2-D particle boundary to produce a full spectrum of fractal dimensions over a range of scales for each particle. Multiple fractal dimensions, which can be described as a fractal spectrum curve, are calculated by taking the first derivative of data points on a standard Richardson plot. Quantitative comparisons are carried out using multivariate statistical techniques such as cluster and principal components analysis. Compared with previous fractal methods that express shape in terms of only one or two fractal dimensions, use of multiple fractal dimensions results in more effective discrimination between samples. In addition, the technique eliminates the subjectivity associated with selecting linear segments on Richardson plots for fractal dimension calculation, and allows direct comparison of particles as long as instantaneous dimensions used as input to multivariate analyses are selected at the same scales for each particle. Applications to samples from well documented eruptions (e.g. Mt. St. Helens, Tambora, Surtsey) indicate that the fractal spectrum technique provides a useful means of characterizing volcanic particles and can be helpful for identifying the products of specific fragmentation processes (volatile exsolution, phreatomagmatic, quench granulation) and modes of volcanic deposition (tephra fall

  11. Elemental composition of the lunar surface: Analysis of gamma ray spectroscopy data from Lunar Prospector

    NASA Astrophysics Data System (ADS)

    Prettyman, T. H.; Hagerty, J. J.; Elphic, R. C.; Feldman, W. C.; Lawrence, D. J.; McKinney, G. W.; Vaniman, D. T.

    2006-12-01

    Gamma ray spectroscopy data acquired by Lunar Prospector are used to determine global maps of the elemental composition of the lunar surface. Maps of the abundance of major oxides, MgO, Al2O3, SiO2, CaO, TiO2, and FeO, and trace incompatible elements, K and Th, are presented along with their geochemical interpretation. Linear spectral mixing is used to model the observed gamma ray spectrum for each map pixel. The spectral shape for each elemental constituent is determined by a Monte Carlo radiation transport calculation. Linearization of the mixing model is accomplished by scaling the spectral shapes with lunar surface parameters determined by neutron spectroscopy, including the number density of neutrons slowing down within the surface and the effective atomic mass of the surface materials. The association of the highlands with the feldspathic lunar meteorites is used to calibrate the mixing model and to determine backgrounds. A linear least squares approach is used to unmix measured spectra to determine the composition of each map pixel. The present analysis uses new gamma ray production cross sections for neutron interactions, resulting in improved accuracy compared to results previously submitted to the Planetary Data System. Systematic variations in lunar composition determined by the spectral unmixing analysis are compared with the lunar soil sample and meteorite collections. Significant results include improved accuracy for the abundance of Th and K in the highlands; identification of large regions, including western Procellarum, that are not well represented by the sample collection; and the association of relatively high concentrations of Mg with KREEP-rich regions on the lunar nearside, which may have implications for the concept of an early magma ocean.

  12. ASpec: A New Spectrum and Line Analysis Package for IRAF

    NASA Technical Reports Server (NTRS)

    Hulbert, Stephen J.

    1996-01-01

    ASpec is a new spectrum and line analysis package developed at STScI. ASpec is designed as an add-on package for IRAF and incorporates a variety of analysis techniques for astronomical spectra. ASpec operates on spectra from a wide variety of ground-based and space-based instruments. ASpec allows simultaneous handling of spectra from different wavelength regimes. ASpec accommodates non-linear dispersion relations. ASpec provides a variety of functions, individually or in combination, with which to fit spectral features and the continuum. ASpec permits the masking of known bad data. ASpec provides a powerful, intuitive graphical user interface implemented using the new IRAF Object Manager and customized to handle: data input/output (I/O); on-line 'help'; selection of relevant features for analysis; plotting and graphical interaction; and data base management.

  13. Mutagenesis in Caenorhabditis elegans. II. A spectrum of mutational events induced with 1500 r of gamma-radiation

    SciTech Connect

    Rosenbluth, R.E.; Cuddeford, C.; Baillie, D.L.

    1985-03-01

    The authors previously established a gamma-ray dose-response curve for recessive lethal events (lethals) captured over the eT1 balancer. In this paper they analyze the nature of lethal events produced, with a frequency of 0.04 per eT1 region, at a dose of 1500 r. To do so, they developed a protocol that, in the absence of cytogenetics, allows balanced lethals to be analyzed for associated chromosomal rearrangements. A set of 35 lethal strains was chosen for the analysis. Although the dosage was relatively low, a large number of multiple-break events were observed. The fraction of lethals associated with rearrangements was found to be 0.76. Currently most X- and gamma-ray dosages used for mutagenesis in C. elegans are 6000-8000 r. From the data it was conservatively estimated that 43% of rearrangements induced with 8000 r would be accompanied by additional chromosome breaks in the genome. With 1500 r the value was 5%. The 35 lethals studied were derived from 875 screened F1's. Among these lethals there were (1) at least two unc-36 duplications, (2) at least four translocations, (3) at least six deficiencies of chromosome V (these delete about 90% of the unc-60 to unc-42 region) and (4) several unanalyzed rearrangements. Thus, it is possible to recover desired rearrangements at reasonable rates with a dose of only 1500 r. The authors suggest that the levels of ionizing radiation employed in most published C. elegans studies are excessive and efforts should be made to use reduced levels in the future.

  14. Spectral and Temporal Analysis of Terrestrial Gamma-Ray Flashes

    NASA Astrophysics Data System (ADS)

    Cramer, E. S.; Dwyer, J. R.; Rassoul, H. K.; Fishman, G. J.; Bhat, N. P.; Briggs, M. S.; Chaplin, V. L.; Connaughton, V.; Fitzpatrick, G.

    2012-12-01

    Terrestrial Gamma-Ray Flashes have been well studied both theoretically and by space based instruments. One of the main mysteries about TGFs is the variation in arrival times between the main "hard" pulse and the "soft" Compton tail. It is well known that TGFs may display symmetric and asymmetric time histories; however, little is known about what intrinsic property of the source allows it to behave the way it does. In this study, we use full Monte Carlo simulations, developed by Dwyer at Florida Tech, to characterize the behavior of the TGF timing with respect to atmospheric depth of the source and the TGF source location with respect to the GBM satellite footprint. The simulation generates the full relativistic runaway electron avalanches and propagates the resulting bremsstrahlung photons through the atmosphere and out to satellite altitude. In this analysis, we use the relativistic runaway electron avalanche model to show some of the clear distinctions between the low energy (< 300 keV) and high energy (> 300 keV) components of the TGF. The Gamma-Ray Burst Monitor aboard the Fermi Gamma-Ray Space Telescope has detected TGFs as short as 50 microseconds. Here, we model those results with the Monte Carlo by simulating different source geometries and heights. We also compare other models in the field to our full Monte Carlo results, and attempt to explain the differences. Therefore, the overall goal of this study is to obtain constraints on the parameter space of TGFs in order to learn something physical about individual events.

  15. Pulsar and diffuse contributions to observed galactic gamma radiation

    NASA Technical Reports Server (NTRS)

    Harding, A. K.; Stecker, F. W.

    1981-01-01

    The first calculation of a gamma-ray production spectrum from pulsars in the Galaxy, along with a statistical analysis of data on 328 known radio pulsars, are presented. The implications of this point source contribution to the general interpretation of the observed galactic gamma-ray spectrum are indicated. The contributions from diffuse interstellar cosmic-ray induced production mechanisms are then re-examined, concluding that pulsars may be contributing significantly to the galactic gamma-ray emission.

  16. Nuclear gamma rays from solar flares. [analysis of theory of gamma ray line emission from solar flares

    NASA Technical Reports Server (NTRS)

    Ramaty, R.; Lingenfelter, R. E.

    1973-01-01

    The theory of gamma-ray line emission from solar flares is reviewed and revised. It is shown that the line emissions at 0.5, 2.2, 4.4, and 6.1 MeV are due to positron annihilation, deuterium deexcitation following neutron capture on hydrogen, and the deexcitation of excited states in carbon and oxygen. From the observed relative line intensities it is possible to determine the spectrum of accelerated protons in the flare region. This spectrum is found to be very similar to that of charged particles from the flare observed near earth. The total number of protons at the sun is deduced from the observed absolute line intensities for various interaction models.

  17. CORONAS-F observation of HXR and gamma-ray emissions from the solar flare X10 on 29 October 2003 as a probe of accelerated proton spectrum

    NASA Astrophysics Data System (ADS)

    Kurt, V. G.; Yushkov, B. Yu.; Kudela, K.; Galkin, V. I.; Kashapova, L. K.

    2015-04-01

    HXR and gamma-ray emissions in the 0.04—150 MeV energy range associated with the solar flare on 29 October 2003 (X10/3B) were observed at 20:38—20:58 UT by the SONG instrument aboard the CORONAS-F mission. We restored consecutive flare gamma-emission spectra from SONG and RHESSI data and found a good agreement of these spectra in the 0.1—10 MeV energy range. Two phases were identified which showed major changes in the spectral shape of flare emission: 20:38:00-20:44:20 UT and 20:44:20-20:58:00 UT. During the second phase an efficiency of proton acceleration increased considerably relatively to the efficiency of acceleration of high energy electrons. The pion-decay component of the flare gamma-emission was elicited statistically significant only during the second phase since 20:47:40 UT. A power law spectrum index of accelerated protons was estimated from the ratio between intensities of the pion-decay and gamma-line components. The hardest spectrum (power law index S=3.7) was at 20:48—20:51 UT when the intensity of the pion-decay emission was maximal. Our subdivision of the flare into two phases is consistent with sharp changes in the structure of the flare found by Ji et al. (2008) and Liu et al. (2009). This flare was accompanied by GLE 66. The time profile of the pion-decay gamma-emission was compared with the GLE onset time. It was shown that both protons interacting at the Sun and the particles responsible for the GLE onset could belong to the same population of accelerated particles.

  18. Improved spectrum simulation for validating SEM-EDS analysis

    NASA Astrophysics Data System (ADS)

    Statham, P.; Penman, C.; Duncumb, P.

    2016-02-01

    X-ray microanalysis by SEM-EDS requires corrections for the many physical processes that affect emitted intensity for elements present in the material. These corrections will only be accurate provided a number of conditions are satisfied and it is essential that the correct elements are identified. As analysis is pushed to achieve results on smaller features and more challenging samples it becomes increasingly difficult to determine if all conditions are upheld and whether the analysis results are valid. If a theoretical simulated spectrum based on the measured analysis result is compared with the measured spectrum, any marked differences will indicate problems with the analysis and can prevent serious mistakes in interpretation. To achieve the necessary accuracy a previous theoretical model has been enhanced to incorporate new line intensity measurements, differential absorption and excitation of emission lines, including the effect of Coster-Kronig transitions and an improved treatment of bremsstrahlung for compounds. The efficiency characteristic has been measured for a large area SDD detector and data acquired from an extensive set of standard materials at both 5 kV and 20 kV. The parameterized model has been adjusted to fit measured characteristic intensities and both background shape and intensity at the same beam current. Examples are given to demonstrate how an overlay of an accurate theoretical simulation can expose some non-obvious mistakes and provide some expert guidance towards a valid analysis result. A new formula for calculating the effective mean atomic number for compounds has also been derived that is appropriate and should help improve accuracy in techniques that calculate the bremsstrahlung or use a bremsstrahlung measurement for calibration.

  19. EBT-P gamma-ray-shielding analysis

    SciTech Connect

    Gohar, Y.

    1983-01-01

    First, a one-dimensional scoping study was performed for the gamma-ray shield of the ELMO Bumpy Torus proof-of-principle device to define appropriate shielding material and determine the required shielding thickness. The dose-equivalent results are analyzed as a function of the radiation-shield thickness for different shielding options. A sensitivity analysis for the pessimistic case is given. The recommended shielding option based on the performance and cost is discussed. Next, a three-dimensional scoping study for the coil shield was performed for four different shielding options to define the heat load for each component and check the compliance with the design criterion of 10 watts maximum heat load per coil from the gamma-ray sources. Also, a detailed biological-dose survey was performed which included: (a) the dose equivalent inside and outside the building, (b) the dose equivalent from the two mazes of the building, and (c) the skyshine contribution to the dose equivalent.

  20. Application of Multidimensional Spectrum Analysis for Analytical Chemistry

    SciTech Connect

    Hatsukawa, Yuichi; Hayakawa, Takehito; Toh, Yosuke; Shinohara, Nobuo; Oshima, Masumi

    1999-12-31

    Feasibility of application of the multidimensional {gamma} ray spectroscopy for analytical chemistry was examined. Two reference igneous rock (JP-1, JB-1a) samples issued by the Geological Survey of Japan (GSJ) were irradiated at a research reactor with thermal neutrons, and {gamma} rays from the radioisotopes produced by neutron capture reactions were measured using a {gamma}-ray detector array. Simultaneously 27 elements were observed with no chemical separation.

  1. Passive gamma analysis of the boiling-water-reactor assemblies

    DOE PAGES

    Vo, D.; Favalli, A.; Grogan, B.; Jansson, P.; Liljenfeldt, H.; Mozin, V.; Schwalbach, P.; Sjöland, A.; Tobin, S.; Trellue, H.; et al

    2016-06-04

    This research focused on the analysis of a set of stationary passive gamma measurements taken on the spent nuclear fuel assemblies from a boiling water reactor (BWR) using pulse height analysis data acquisition. The measurements were performed on 25 different BWR assemblies in 2014 at Sweden’s Central Interim Storage Facility for Spent Nuclear Fuel (Clab). This study was performed as part of the Next Generation of Safeguards Initiative–Spent Fuel project to research the application of nondestructive assay (NDA) to spent fuel assemblies. The NGSI–SF team is working to achieve the following technical goals more easily and efficiently than in themore » past using nondestructive assay (NDA) measurements of spent fuel assemblies: (1) verify the initial enrichment, burnup, and cooling time of facility declaration; (2) detect the diversion or replacement of pins, (3) estimate the plutonium mass, (4) estimate the decay heat, and (5) determine the reactivity of spent fuel assemblies. The final objective of this project is to quantify the capability of several integrated NDA instruments to meet the aforementioned goals using the combined signatures of neutrons, gamma rays, and heat. This report presents a selection of the measured data and summarizes an analysis of the results. Specifically, trends in the count rates measured for spectral lines from the following isotopes were analyzed as a function of the declared burnup and cooling time: 137Cs, 154Eu, 134Cs, and to a lesser extent, 106Ru and 144Ce. From these measured count rates, predictive algorithms were developed to enable the estimation of the burnup and cooling time. Furthermore, these algorithms were benchmarked on a set of assemblies not included in the standard assemblies set used by this research team.« less

  2. Passive gamma analysis of the boiling-water-reactor assemblies

    NASA Astrophysics Data System (ADS)

    Vo, D.; Favalli, A.; Grogan, B.; Jansson, P.; Liljenfeldt, H.; Mozin, V.; Schwalbach, P.; Sjöland, A.; Tobin, S.; Trellue, H.; Vaccaro, S.

    2016-09-01

    This research focused on the analysis of a set of stationary passive gamma measurements taken on the spent nuclear fuel assemblies from a boiling water reactor (BWR) using pulse height analysis data acquisition. The measurements were performed on 25 different BWR assemblies in 2014 at Sweden's Central Interim Storage Facility for Spent Nuclear Fuel (Clab). This study was performed as part of the Next Generation of Safeguards Initiative-Spent Fuel project to research the application of nondestructive assay (NDA) to spent fuel assemblies. The NGSI-SF team is working to achieve the following technical goals more easily and efficiently than in the past using nondestructive assay (NDA) measurements of spent fuel assemblies: (1) verify the initial enrichment, burnup, and cooling time of facility declaration; (2) detect the diversion or replacement of pins, (3) estimate the plutonium mass, (4) estimate the decay heat, and (5) determine the reactivity of spent fuel assemblies. The final objective of this project is to quantify the capability of several integrated NDA instruments to meet the aforementioned goals using the combined signatures of neutrons, gamma rays, and heat. This report presents a selection of the measured data and summarizes an analysis of the results. Specifically, trends in the count rates measured for spectral lines from the following isotopes were analyzed as a function of the declared burnup and cooling time: 137Cs, 154Eu, 134Cs, and to a lesser extent, 106Ru and 144Ce. From these measured count rates, predictive algorithms were developed to enable the estimation of the burnup and cooling time. Furthermore, these algorithms were benchmarked on a set of assemblies not included in the standard assemblies set used by this research team.

  3. Low-Frequency Repetitive Transcranial Magnetic Stimulation (rTMS) Modulates Evoked-Gamma Frequency Oscillations in Autism Spectrum Disorder (ASD)

    PubMed Central

    Baruth, Joshua M.; Casanova, Manuel F.; El-Baz, Ayman; Horrell, Tim; Mathai, Grace; Sears, Lonnie; Sokhadze, Estate

    2010-01-01

    Introduction It has been reported that individuals with Autism Spectrum Disorder (ASD) have abnormal reactions to the sensory environment and visuo-perceptual abnormalities. Electrophysiological research has provided evidence that gamma band activity (30-80 Hz) is a physiological indicator of the co-activation of cortical cells engaged in processing visual stimuli and integrating different features of a stimulus. A number of studies have found augmented and indiscriminative gamma band power at early stages of visual processing in ASD; this may be related to decreased inhibitory processing and an increase in the ratio of cortical excitation to inhibition. Low frequency or ‘slow’ (≤1HZ) repetitive transcranial magnetic stimulation (rTMS) has been shown to increase inhibition of stimulated cortex by the activation of inhibitory circuits. Methods We wanted to test the hypothesis of gamma band abnormalities at early stages of visual processing in ASD by investigating relative evoked (i.e. ~ 100 ms) gamma power in 25 subjects with ASD and 20 age-matched controls using Kanizsa illusory figures. Additionally, we wanted to assess the effects of 12 sessions of bilateral ‘slow’ rTMS to the dorsolateral prefrontal cortex (DLPFC) on evoked gamma activity using a randomized controlled design. Results In individuals with ASD evoked gamma activity was not discriminative of stimulus type, whereas in controls early gamma power differences between target and non-target stimuli were highly significant. Following rTMS individuals with ASD showed significant improvement in discriminatory gamma activity between relevant and irrelevant visual stimuli. We also found significant improvement in the responses on behavioral questionnaires (i.e., irritability, repetitive behavior) as a result of rTMS. Conclusion We proposed that ‘slow’ rTMS may have increased cortical inhibitory tone which improved discriminatory gamma activity at early stages of visual processing. rTMS has the

  4. Understanding Doppler Broadening of Gamma Rays

    SciTech Connect

    Rawool-Sullivan, Mohini; Sullivan, John P.

    2014-07-03

    Doppler-broadened gamma ray peaks are observed routinely in the collection and analysis of gamma-ray spectra. If not recognized and understood, the appearance of Doppler broadening can complicate the interpretation of a spectrum and the correct identification of the gamma ray-emitting material. We have conducted a study using a simulation code to demonstrate how Doppler broadening arises and provide a real-world example in which Doppler broadening is found. This report describes that study and its results.

  5. ASpect: A new spectrum and line analysis package for IRAF

    NASA Technical Reports Server (NTRS)

    Hulbert, S. J.; Eisenhamer, J. D.; Levay, Z. G.; Shaw, R. A.

    1992-01-01

    We examined several publicly available spectral analysis software packages looking for one with enough functionality and versatility to meet the analysis needs of astronomers during the next decade. None of those examined can satisfactorily support the wide variety of panchromatic science programs that are now becoming possible. Furthermore, we concluded that none of these packages can be simply modified to include critical functions because of their original (limited) designs. During the next two years we will write a new spectral analysis package, ASpect, that will incorporate the latest analysis techniques for astronomical spectra in all wavelength domains. The ASpect package has several functional requirements. It must operate on spectra from a wide variety of ground-based and space-based instruments spanning wavelengths from radio to gamma rays. It must accommodate non-linear dispersion relations. It must provide a variety of functions, individually or in combination, with which to fit spectral features and the continuum. It is vitally important that known bad data be masked and that, uncertainties be propagated throughout the calculations in order for astronomers to evaluate the reliability of results. Finally, this new package must provide a powerful, intuitive graphical user interface to handle the burden of data input/output (I/O), on-line 'help,' selection of relevant features for analysis, plotting and graphical interaction, and data base management--all in a comprehensible environment. We anticipate that ASpect will take the form of an external package in IRAF (such as the NOAO and STSDAS packages) and will be layered upon the IRAF virtual Operating System to make it available on as many platforms as possible, while making it resistant to changes in operating systems and compilers. Our choice of IRAF is motivated by its portability, its wide use within the astronomical community, and its rich set of existing user applications.

  6. BAYESIAN ANGULAR POWER SPECTRUM ANALYSIS OF INTERFEROMETRIC DATA

    SciTech Connect

    Sutter, P. M.; Wandelt, Benjamin D.; Malu, Siddarth S.

    2012-09-15

    We present a Bayesian angular power spectrum and signal map inference engine which can be adapted to interferometric observations of anisotropies in the cosmic microwave background (CMB), 21 cm emission line mapping of galactic brightness fluctuations, or 21 cm absorption line mapping of neutral hydrogen in the dark ages. The method uses Gibbs sampling to generate a sampled representation of the angular power spectrum posterior and the posterior of signal maps given a set of measured visibilities in the uv-plane. We use a mock interferometric CMB observation to demonstrate the validity of this method in the flat-sky approximation when adapted to take into account arbitrary coverage of the uv-plane, mode-mode correlations due to observations on a finite patch, and heteroschedastic visibility errors. The computational requirements scale as O(n{sub p} log n{sub p}) where n{sub p} measures the ratio of the size of the detector array to the inter-detector spacing, meaning that Gibbs sampling is a promising technique for meeting the data analysis requirements of future cosmology missions.

  7. Terahertz spectrum analysis of leather at room temperature

    NASA Astrophysics Data System (ADS)

    Li, Jiusheng; Yao, Jianquan; Li, Jianrui

    2008-12-01

    Over the past ten years, electromagnetic terahertz (THz) frequencies region from 100 GHz to 10 THz (or wavelengths of 30 μm ~3 mm) have received extensive attention and investigation. Terahertz wave detection enables direct calculations of both the imaginary and the real parts of the refractive index without using the Kramers-Kronig relations. There are many potential applications such as radio astronomy, atmospheric studies, remote sensing, and plasma diagnostics. Shoes, neckties and sofa, etc are mainly made of skin of animal, imitated skin and artificial leather. It has important practical value to component analysis and quality assessment by measuring absorption, refractive index, and other optical parameters. In this paper, the spectral characteristics of sheepskin, imitated sheepskin and artificial leather have been measured with terahertz time-domain spectroscopy (THz-TDS) in the range of 0.1~2.0THz. The results show that there have not absorption peak in the absorption spectrum of the sheepskin. However, it is found that there are three absorption peaks in the absorption spectrum of the artificial leather at the frequency of 1.13THz, 1.21THz, and 1.36THz, respectively. The potential application of the leather in THz frequency region is also discussed.

  8. Can the cosmic x ray and gamma ray background be due to reflection of a steep power law spectrum and Compton scattering by relativistic electrons?

    NASA Technical Reports Server (NTRS)

    Zycki, Piotr T.; Zdziarski, Andrzej A.; Svensson, Roland

    1991-01-01

    We reconsider the recent model for the origin in the cosmic X-ray and gamma-ray background by Rogers and Field. The background in the model is due to an unresolved population of AGNs. An individual AGN spectrum contains three components: a power law with the energy index of alpha = 1.1, an enhanced reflection component, and a component from Compton scattering by relativistic electrons with a low energy cutoff at some minimum Lorentz factor, gamma(sub min) much greater than 1. The MeV bump seen in the gamma-ray background is then explained by inverse Compton emission by the electrons. We show that the model does not reproduce the shape of the observed X-ray and gamma-ray background below 10 MeV and that it overproduces the background at larger energies. Furthermore, we find the assumptions made for the Compton component to be physically inconsistent. Relaxing the inconsistent assumptions leads to model spectra even more different from that of the observed cosmic background. Thus, we can reject the hypothesis that the high-energy cosmic background is due to the described model.

  9. Reduction of S-parameter errors using singular spectrum analysis.

    PubMed

    Ozturk, Turgut; Uluer, İhsan; Ünal, İlhami

    2016-07-01

    A free space measurement method, which consists of two horn antennas, a network analyzer, two frequency extenders, and a sample holder, is used to measure transmission (S21) coefficients in 75-110 GHz (W-Band) frequency range. Singular spectrum analysis method is presented to eliminate the error and noise of raw S21 data after calibration and measurement processes. The proposed model can be applied easily to remove the repeated calibration process for each sample measurement. Hence, smooth, reliable, and accurate data are obtained to determine the dielectric properties of materials. In addition, the dielectric constant of materials (paper, polyvinylchloride-PVC, Ultralam® 3850HT, and glass) is calculated by thin sheet approximation and Newton-Raphson extracting techniques using a filtered S21 transmission parameter. PMID:27475579

  10. Mutational Spectrum Analysis of Neurodegenerative Diseases and Its Pathogenic Implication.

    PubMed

    Shen, Liang; Ji, Hong-Fang

    2015-10-14

    One of the most conspicuous features of neurodegenerative diseases (NDs) is the occurrence of dramatic conformation change of individual proteins. We performed a mutational spectrum analysis of disease-causing missense mutations in seven types of NDs at nucleotide and amino acid levels, and compared the results with those of non-NDs. The main findings included: (i) The higher mutation ratio of G:C→T:A transversion to G:C→A:T transition was observed in NDs than in non-NDs, interpreting the excessive guanine-specific oxidative DNA damage in NDs; (ii) glycine and proline had highest mutability in NDs than in non-NDs, which favor the protein conformation change in NDs; (iii) surprisingly low mutation frequency of arginine was observed in NDs. These findings help to understand how mutations may cause NDs.

  11. Reduction of S-parameter errors using singular spectrum analysis.

    PubMed

    Ozturk, Turgut; Uluer, İhsan; Ünal, İlhami

    2016-07-01

    A free space measurement method, which consists of two horn antennas, a network analyzer, two frequency extenders, and a sample holder, is used to measure transmission (S21) coefficients in 75-110 GHz (W-Band) frequency range. Singular spectrum analysis method is presented to eliminate the error and noise of raw S21 data after calibration and measurement processes. The proposed model can be applied easily to remove the repeated calibration process for each sample measurement. Hence, smooth, reliable, and accurate data are obtained to determine the dielectric properties of materials. In addition, the dielectric constant of materials (paper, polyvinylchloride-PVC, Ultralam® 3850HT, and glass) is calculated by thin sheet approximation and Newton-Raphson extracting techniques using a filtered S21 transmission parameter.

  12. Reduction of S-parameter errors using singular spectrum analysis

    NASA Astrophysics Data System (ADS)

    Ozturk, Turgut; Uluer, Ihsan; Ünal, Ilhami

    2016-07-01

    A free space measurement method, which consists of two horn antennas, a network analyzer, two frequency extenders, and a sample holder, is used to measure transmission (S21) coefficients in 75-110 GHz (W-Band) frequency range. Singular spectrum analysis method is presented to eliminate the error and noise of raw S21 data after calibration and measurement processes. The proposed model can be applied easily to remove the repeated calibration process for each sample measurement. Hence, smooth, reliable, and accurate data are obtained to determine the dielectric properties of materials. In addition, the dielectric constant of materials (paper, polyvinylchloride-PVC, Ultralam® 3850HT, and glass) is calculated by thin sheet approximation and Newton-Raphson extracting techniques using a filtered S21 transmission parameter.

  13. Performance analysis of spread spectrum modulation in data hiding

    NASA Astrophysics Data System (ADS)

    Gang, Litao; Akansu, Ali N.; Ramkumar, Mahalingam

    2001-12-01

    Watermarking or steganography technology provides a possible solution in digital multimedia copyright protection and pirate tracking. Most of the current data hiding schemes are based on spread spectrum modulation. A small value watermark signal is embedded into the content signal in some watermark domain. The information bits can be extracted via correlation. The schemes are applied both in escrow and oblivious cases. This paper reveals, through analysis and simulation, that in oblivious applications where the original signal is not available, the commonly used correlation detection is not optimal. Its maximum likelihood detection is analyzed and a feasible suboptimal detector is derived. Its performance is explored and compared with the correlation detector. Subsequently a linear embedding scheme is proposed and studied. Experiments with image data hiding demonstrates its effectiveness in applications.

  14. Quantification of tissue texture with photoacoustic spectrum analysis

    NASA Astrophysics Data System (ADS)

    Wang, Xueding; Xu, Guan; Meng, Zhuo-Xian; Lin, Jiandie; Carson, Paul

    2014-05-01

    Photoacoustic (PA) imaging is an emerging technology that could map the functional contrasts in deep biological tissues in high resolution by "listening" to the laser induced thermoelastic waves. Almost all of the current studies in PA imaging are focused on the intensity of the PA signals as an indication of the optical absorbance of the biological tissues. Our group has for the first time demonstrated that the frequency domain power distribution of the broadband PA signals encode the texture information within the regions-of-interest (ROI). Following the similar method of ultrasound spectral analysis (USSA), photoacoustic spectrum analysis (PASA) could evaluate the relative concentrations and, more importantly, the dimensions of microstructures of the optically absorbing materials in biological tissues, including lipid, collagen, water and hemoglobin. By providing valuable insights into tissue pathology, PASA should benefit basic research and clinical management of many diseases, and may help achieve eventual "noninvasive biopsy". In this work, taking advantage of the optical absorption contrasts contributed by lipid and hemoglobin at 1200-nm and 532-nm wavelengths respectively, we investigated the capability of PASA in identifying histological changes corresponding to fat accumulation livers through the study on ex vivo and in situ mouse models. The PA signals from the mouse livers were acquired using our PA and US dual-modality imaging system, and analyzed in the frequency domain. After quantifying the power spectrum by fitting it to a first order model, three spectral parameters, including the intercept, the midband fit and the slope, were extracted and used to differentiate fatty livers from normal livers. The comparison between the PASA parameters from the normal and the fatty livers supports our hypotheses that PASA can quantitatively identify the microstructure changes in liver tissues for differentiating normal and fatty livers.

  15. Wind speed power spectrum analysis for Bushland, Texas

    SciTech Connect

    Eggleston, E.D.

    1996-12-31

    Numerous papers and publications on wind turbulence have referenced the wind speed spectrum presented by Isaac Van der Hoven in his article entitled Power Spectrum of Horizontal Wind Speed Spectrum in the Frequency Range from 0.0007 to 900 Cycles per Hour. Van der Hoven used data measured at different heights between 91 and 125 meters above the ground, and represented the high frequency end of the spectrum with data from the peak hour of hurricane Connie. These facts suggest we should question the use of his power spectrum in the wind industry. During the USDA - Agricultural Research Service`s investigation of wind/diesel system power storage, using the appropriate wind speed power spectrum became a significant issue. We developed a power spectrum from 13 years of hourly average data, 1 year of 5 minute average data, and 2 particularly gusty day`s 1 second average data all collected at a height of 10 meters. While the general shape is similar to the Van der Hoven spectrum, few of his peaks were found in the Bushland spectrum. While higher average wind speeds tend to suggest higher amplitudes in the high frequency end of the spectrum, this is not always true. Also, the high frequency end of the spectrum is not accurately described by simple wind statistics such as standard deviation and turbulence intensity. 2 refs., 5 figs., 1 tab.

  16. Multi-shot analysis of the gamma reaction history diagnostic

    SciTech Connect

    Sayre, D. B.; Bernstein, L. A.; Church, J. A.; Stoeffl, W.; Herrmann, H. W.

    2012-10-15

    The gamma reaction history diagnostic at the National Ignition Facility has the capability to determine a number of important performance metrics for cryogenic deuterium-tritium implosions: the fusion burn width, bang time and yield, as well as the areal density of the compressed ablator. Extracting those values from the measured {gamma} rays of an implosion, requires accounting for a {gamma}-ray background in addition to the impulse response function of the instrument. To address these complications, we have constructed a model of the {gamma}-ray signal, and are developing a simultaneous multi-shot fitting routine to constrain its parameter space.

  17. Automated gamma spectrometry and data analysis on radiometric neutron dosimeters

    SciTech Connect

    Matsumoto, W.Y.

    1983-01-01

    An automated gamma-ray spectrometry system was designed and implemented by the Westinghouse Hanford Company at the Hanford Engineering Development Laboratory (HEDL) to analyze radiometric neutron dosimeters. Unattended, automatic, 24 hour/day, 7 day/week operation with online data analysis and mainframe-computer compatible magnetic tape output are system features. The system was used to analyze most of the 4000-plus radiometric monitors (RM's) from extensive reactor characterization tests during startup and initial operation of th Fast Flux Test Facility (FFTF). The FFTF, operated by HEDL for the Department of Energy, incorporates a 400 MW(th) sodium-cooled fast reactor. Aumomated system hardware consists of a high purity germanium detector, a computerized multichannel analyzer data acquisition system (Nuclear Data, Inc. Model 6620) with two dual 2.5 Mbyte magnetic disk drives plus two 10.5 inch reel magnetic tape units for mass storage of programs/data and an automated Sample Changer-Positioner (ASC-P) run with a programmable controller. The ASC-P has a 200 sample capacity and 12 calibrated counting (analysis) positions ranging from 6 inches (15 cm) to more than 20 feet (6.1 m) from the detector. The system software was programmed in Fortran at HEDL, except for the Nuclear Data, Inc. Peak Search and Analysis Program and Disk Operating System (MIDAS+).

  18. A mass spectroscopic analysis of {gamma}-GPS films

    SciTech Connect

    Dillingham, R.G.; Boerio, F.J.; Bertelsen, C.; Savina, M.R.; Lykke, K.; Calaway, W.

    1996-12-31

    Preparation of substrates for painting or adhesive bonding frequently includes roughening through sanding, chemical etching, or gritblasting. Increased roughness can improve interfacial strength and durability due to increased mechanical interlocking, increased surface area, and improved wettability of the substrate. The chemical reactivity of the surface with the organic phase may be affected as well, perhaps related to the strain energy stored in the surface regions through the intense plastic deformation that occurs. Unfortunately, the chemistry of interactions taking place near a surface that has been roughened is difficult to access analytically by some of the more useful techniques such as infrared spectroscopy. This paper discusses analysis of nonreflective grit-blasted surfaces using mass spectroscopy of species which were either sputtered off using an ion beam (Static Secondary Ion Mass Spectroscopy, or SSIMS) or thermally desorbed as neutrals using a pulsed laser and then post-ionized using a secondary laser (Laser Desorption-Laser Ionization Mass Spectroscopy, or LDLIMS). Both of these techniques exhibit sub-nanometer sensitivity and provide significant information as to the chemistry and structure of the surface regions. In a current application of {gamma}-glycidoxypropyltrimethoxysilane ({gamma}-GPS) for the pre-treatment of grit-blasted aluminum before adhesive bonding, certain factors related to the handling of the primer solution and to the application technique were found to significantly affect the performance of the adhesive bond under long-term aging conditions including stress and humidity. To understand why these parameters are important and to potentially improve the pretreatment process even further, the authors have been investigating how the structure and reactivity of these silane films are related to the application techniques.

  19. EGAF: Measurement and Analysis of Gamma-ray Cross Sections

    NASA Astrophysics Data System (ADS)

    Firestone, R. B.; Abusaleem, K.; Basunia, M. S.; Bečvář, F.; Belgya, T.; Bernstein, L. A.; Choi, H. D.; Escher, J. E.; Genreith, C.; Hurst, A. M.; Krtička, M.; Renne, P. R.; Révay, Zs.; Rogers, A. M.; Rossbach, M.; Siem, S.; Sleaford, B.; Summers, N. C.; Szentmiklosi, L.; van Bibber, K.; Wiedeking, M.

    2014-05-01

    The Evaluated Gamma-ray Activation File (EGAF) is the result of a 2000-2007 IAEA Coordinated Research Project to develop a database of thermal, prompt γ-ray cross sections, σγ, for all elemental and selected radioactive targets. No previous database of this kind had existed. EGAF was originally based on measurements using guided neutron beams from the Budapest Reactor on all elemental targets from Z=1-82, 90 and 92, except for He and Pm. The EGAF σγ data were published in the Database of Prompt Gamma Rays from Slow Neutron Capture for Elemental Analysis [1]. An international collaboration has formed to continue the EGAF measurements with isotopically enriched targets, derive total radiative thermal neutron cross sections, σ0, extend the σγ data from thermal to 20 MeV neutrons, compile a completed activation data file, improve sections of the Reference Input Parameter Library (RIPL) with more complete and up to date level and γ-ray data, evaluate statistical γ-ray data from reaction studies, and determine recommended neutron separations energies, Sn, for atomic mass evaluations. A new guided neutron beam facility has become available at the Garching (Munich) FRM II Reactor, and high energy neutron experimental facilities are being developed by a Berkeley area collaboration where 5-33 MeV neutron beams are available at the LBNL 88” cyclotron, 2.5 and 14 MeV beams at the University of California, Berkeley neutron generator laboratory, and high flux, 10 nṡcmṡ-2 s-1, neutron pulses available from the LLNL National Ignition Facility (NIF).

  20. A revised analysis of gamma-ray bursts' prompt efficiencies

    NASA Astrophysics Data System (ADS)

    Beniamini, Paz; Nava, Lara; Piran, Tsvi

    2016-09-01

    The prompt gamma-ray bursts' (GRBs) efficiency is an important clue on the emission mechanism producing the γ-rays. Previous estimates of the kinetic energy of the blast waves, based on the X-ray afterglow luminosity LX, suggested that this efficiency is large, with values above 90 per cent in some cases. This poses a problem to emission mechanisms and in particular to the internal shocks model. These estimates are based, however, on the assumption that the X-ray emitting electrons are fast cooling and that their Inverse Compton (IC) losses are negligible. The observed correlations between LX (and hence the blast wave energy) and Eγ, iso, the isotropic equivalent energy in the prompt emission, has been considered as observational evidence supporting this analysis. It is reasonable that the prompt gamma-ray energy and the blast wave kinetic energy are correlated and the observed correlation corroborates, therefore, the notion LX is indeed a valid proxy for the latter. Recent findings suggest that the magnetic field in the afterglow shocks is significantly weaker than was earlier thought and its equipartition fraction, ɛB, could be as low as 10-4 or even lower. Motivated by these findings we reconsider the problem, taking now IC cooling into account. We find that the observed LX - Eγ, iso correlation is recovered also when IC losses are significant. For small ɛB values the blast wave must be more energetic and we find that the corresponding prompt efficiency is significantly smaller than previously thought. For example, for ɛB ˜ 10-4 we infer a typical prompt efficiency of ˜15 per cent.

  1. New Mexico Play Fairway Analysis: Gamma Ray Logs and Heat Generation Calculations for SW New Mexico

    SciTech Connect

    Shari Kelley

    2015-10-23

    For the New Mexico Play fairway Analysis project, gamma ray geophysical well logs from oil wells penetrating the Proterozoic basement in southwestern New Mexico were digitized. Only the portion of the log in the basement was digitized. The gamma ray logs are converted to heat production using the equation (Bucker and Rybach, 1996) : A[µW/m3] = 0.0158 (Gamma Ray [API] – 0.8).

  2. Spectral analysis of shielded gamma ray sources using precalculated library data

    NASA Astrophysics Data System (ADS)

    Holmes, Thomas Wesley; Gardner, Robin P.

    2015-11-01

    In this work, an approach has been developed for determining the intensity of a shielded source by first determining the thicknesses of three different shielding materials from a passively collected gamma-ray spectrum by making comparisons with predetermined shielded spectra. These evaluations are dependent on the accuracy and validity of the predetermined library spectra which were created by changing the thicknesses of the three chosen materials lead, aluminum and wood that are used to simulate any actual shielding. Each of the spectra produced was generated using MCNP5 with a sufficiently large number of histories to ensure a low relative error at each channel. The materials were held in the same respective order from source to detector, where each material consisted of three individual thicknesses and a null condition. This then produced two separate data sets of 27 total shielding material situations and subsequent predetermined libraries that were created for each radionuclide source used. The technique used to calculate the thicknesses of the materials implements a Levenberg-Marquardt nonlinear search that employs a tri-linear interpolation with the respective predetermined libraries within each channel for the supplied input unknown spectrum. Given that the nonlinear parameters require an initial guess for the calculations, the approach demonstrates first that when the correct values are input, the correct thicknesses are found. It then demonstrates that when multiple trials of random values are input for each of the nonlinear parameters, the average of the calculated solutions that successfully converges also produced the correct thicknesses. Under situations with sufficient information known about the detection situation at hand, the method was shown to behave in a manner that produces reasonable results and can serve as a good preliminary solution. This technique has the capability to be used in a variety of full spectrum inverse analysis problems

  3. BLIND EXTRACTION OF AN EXOPLANETARY SPECTRUM THROUGH INDEPENDENT COMPONENT ANALYSIS

    SciTech Connect

    Waldmann, I. P.; Tinetti, G.; Hollis, M. D. J.; Yurchenko, S. N.; Tennyson, J.; Deroo, P.

    2013-03-20

    Blind-source separation techniques are used to extract the transmission spectrum of the hot-Jupiter HD189733b recorded by the Hubble/NICMOS instrument. Such a 'blind' analysis of the data is based on the concept of independent component analysis. The detrending of Hubble/NICMOS data using the sole assumption that nongaussian systematic noise is statistically independent from the desired light-curve signals is presented. By not assuming any prior or auxiliary information but the data themselves, it is shown that spectroscopic errors only about 10%-30% larger than parametric methods can be obtained for 11 spectral bins with bin sizes of {approx}0.09 {mu}m. This represents a reasonable trade-off between a higher degree of objectivity for the non-parametric methods and smaller standard errors for the parametric de-trending. Results are discussed in light of previous analyses published in the literature. The fact that three very different analysis techniques yield comparable spectra is a strong indication of the stability of these results.

  4. The distinction between gamma-quanta spectra from both local sources and cosmic rays, and the formation of a uniform cosmic ray spectrum

    NASA Astrophysics Data System (ADS)

    Nikolsky, S. I.; Sinitsyna, V. G.

    2003-07-01

    The experimental data about gamma-quanta sources with energy > 1 TeV are characterised by the fact that the observed metagalactic sources (active galactic nuclei) are 106 - 107 times more powerful than the galactic ones, but they do not differ in energy spectrum (F(> Eγ)~Eγ-1.3+/-0.15). The power of metagalactic sources and their unlimited number puts into doubt the assumption about the galactic origin of the observable cosmic ray flux. It is possible to assume, that the uniform cosmic ray spectrum is formed (by ``braking'') in an ``infinite'' number of elastic (or inelastic) collisions with relict photons in intergalactic space. Thus, the observable spectral distribution of protons and cosmic ray nuclei with index of (2.72+/-0.02) = 2.718... (the Nipper's number) is the consequence of such ``braking'' warming up the relict photons. RFBR, FNP, GNTP

  5. Galactic plane gamma-radiation

    NASA Technical Reports Server (NTRS)

    Hartman, R. C.; Kniffen, D. A.; Thompson, D. J.; Fichtel, C. E.; Ogelman, H. B.; Tumer, T.; Ozel, M. E.

    1979-01-01

    Analysis of the SAS 2 data together with the COS B results shows that the distribution of galactic gamma-radiation has several similarities to that of other large-scale tracers of galactic structure. The radiation is primarily confined to a thin disc which exhibits offsets from b = 0 degrees similar to warping at radio frequencies. The principal distinction of the gamma-radiation is a stronger contrast in intensity between the region from 310 to 45 degrees in longitude and the regions away from the center that can be attributed to a variation in cosmic-ray density as a function of position in Galaxy. The diffuse galactic gamma-ray energy spectrum shows no significant variation in direction, and the spectrum seen along the plane is the same as that for the galactic component of the gamma-radiation at high altitudes. The uniformity of the galactic gamma-ray spectrum, the smooth decrease in intensity as a function of altitude, and the absence of any galactic gamma-ray sources at high altitudes indicate a diffuse origin for bulk of the galactic gamma-radiation rather than a collection of localized sources.

  6. Coincidence Prompt Gamma-Ray Neutron Activation Analysis

    SciTech Connect

    R.P. gandner; C.W. Mayo; W.A. Metwally; W. Zhang; W. Guo; A. Shehata

    2002-11-10

    The normal prompt gamma-ray neutron activation analysis for either bulk or small beam samples inherently has a small signal-to-noise (S/N) ratio due primarily to the neutron source being present while the sample signal is being obtained. Coincidence counting offers the possibility of greatly reducing or eliminating the noise generated by the neutron source. The present report presents our results to date on implementing the coincidence counting PGNAA approach. We conclude that coincidence PGNAA yields: (1) a larger signal-to-noise (S/N) ratio, (2) more information (and therefore better accuracy) from essentially the same experiment when sophisticated coincidence electronics are used that can yield singles and coincidences simultaneously, and (3) a reduced (one or two orders of magnitude) signal from essentially the same experiment. In future work we will concentrate on: (1) modifying the existing CEARPGS Monte Carlo code to incorporate coincidence counting, (2) obtaining coincidence schemes for 18 or 20 of the common elements in coal and cement, and (3) optimizing the design of a PGNAA coincidence system for the bulk analysis of coal.

  7. Power spectrum analysis for defect screening in integrated circuit devices

    DOEpatents

    Tangyunyong, Paiboon; Cole Jr., Edward I.; Stein, David J.

    2011-12-01

    A device sample is screened for defects using its power spectrum in response to a dynamic stimulus. The device sample receives a time-varying electrical signal. The power spectrum of the device sample is measured at one of the pins of the device sample. A defect in the device sample can be identified based on results of comparing the power spectrum with one or more power spectra of the device that have a known defect status.

  8. Spatiotemporal analysis of the appearance of gamma-band Microstates in resting state MEG.

    PubMed

    Kelsey, Matthew; Prior, Fred W; Larson-Prior, Linda J

    2015-01-01

    Spatiotemporal analysis of EEG signal has revealed a rich set of methods to quantify neuronal activity using spatially global topographic templates, called Microstates. These methods complement more traditional spectral analysis, which uses band limited source data to determine defining differences in band power and peak characteristics. The high sampling rate and increased resistance to high frequency noise of MEG data offers an opportunity to explore the utility of spatiotemporal analysis over a wider spectrum than in EEG. In this work, we explore the utility of representing band limited MEG source data using established microstate techniques, especially in gamma frequency bands - a range yet unexplored using these techniques. We develop methods for gauging the goodness-of-fit achieved by resultant microstate templates and demonstrate sensor-level dispersion characteristics across wide-band signals as well as across signals filtered by canonical bands. These analyses reveal that, while high-frequency-band derived microstate templates are visually lawful, they fail to exhibit important explained variance and dispersion characteristics present in low- and full-band data necessary to meet the requirements of a microstate model.

  9. Eliminating Bias In Acousto-Optical Spectrum Analysis

    NASA Technical Reports Server (NTRS)

    Ansari, Homayoon; Lesh, James R.

    1992-01-01

    Scheme for digital processing of video signals in acousto-optical spectrum analyzer provides real-time correction for signal-dependent spectral bias. Spectrum analyzer described in "Two-Dimensional Acousto-Optical Spectrum Analyzer" (NPO-18092), related apparatus described in "Three-Dimensional Acousto-Optical Spectrum Analyzer" (NPO-18122). Essence of correction is to average over digitized outputs of pixels in each CCD row and to subtract this from the digitized output of each pixel in row. Signal processed electro-optically with reference-function signals to form two-dimensional spectral image in CCD camera.

  10. Characterization of bone microstructure using photoacoustic spectrum analysis.

    PubMed

    Feng, Ting; Perosky, Joseph E; Kozloff, Kenneth M; Xu, Guan; Cheng, Qian; Du, Sidan; Yuan, Jie; Deng, Cheri X; Wang, Xueding

    2015-09-21

    Osteoporosis is a progressive bone disease that is characterized by a decrease in bone mass and the deterioration in bone microarchitecture. This study investigates the feasibility of characterizing bone microstructure by analyzing the frequency spectrum of the photoacoustic (PA) signal from the bone. Modeling and numerical simulation of PA signal were performed on trabecular bone simulations and CT scans with different trabecular thicknesses. The resulting quasi-linear photoacoustic spectra were fittted by linear regression, from which the spectral parameter slope was quantified. The simulation based on two different models both demonstrate that bone specimens with thinner trabecular thicknesses have higher slope. Experiment on osteoporotic rat femoral heads with different mineral content was conducted. The finding from the experiment was in good agreement with the simulation, demonstrating that the frequency-domain analysis of PA signals can provide an objective assessment of bone microstructure and deterioration. Considering that PA measurement is non-ionizing, non-invasive, and has sufficient penetration in both calcified and non-calcified tissues, this new bone evaluation method based on photoacoustic spectral analysis holds potential for clinical management of osteoporosis and other bone diseases.

  11. Characterization of bone microstructure using photoacoustic spectrum analysis

    NASA Astrophysics Data System (ADS)

    Feng, Ting; Kozloff, Kenneth M.; Xu, Guan; Du, Sidan; Yuan, Jie; Deng, Cheri X.; Wang, Xueding

    2015-03-01

    Osteoporosis is a progressive bone disease that is characterized by a decrease in bone mass and deterioration in microarchitecture. This study investigates the feasibility of characterizing bone microstructure by analyzing the frequency spectrum of the photoacoustic signals from the bone. Modeling and numerical simulation of photoacoustic signals and their frequency-domain analysis were performed on trabecular bones with different mineral densities. The resulting quasilinear photoacoustic spectra were fit by linear regression, from which spectral parameter slope can be quantified. The modeling demonstrates that, at an optical wavelength of 685 nm, bone specimens with lower mineral densities have higher slope. Preliminary experiment on osteoporosis rat tibia bones with different mineral contents has also been conducted. The finding from the experiment has a good agreement with the modeling, both demonstrating that the frequency-domain analysis of photoacoustic signals can provide objective assessment of bone microstructure and deterioration. Considering that photoacoustic measurement is non-ionizing, non-invasive, and has sufficient penetration in both calcified and noncalcified tissues, this new technology holds unique potential for clinical translation.

  12. SPECTRAL ANALYSIS AND INTERPRETATION OF THE {gamma}-RAY EMISSION FROM THE STARBURST GALAXY NGC 253

    SciTech Connect

    Abramowski, A.; Acero, F.; Akhperjanian, A. G.; Anton, G.; Balzer, A.; Brucker, J.; Barnacka, A.; Becherini, Y.; Birsin, E.; Biteau, J.; Brun, F.; Bolmont, J.; Brun, P.; Collaboration: H.E.S.S. Collaboration; and others

    2012-10-01

    Very high energy (VHE; E {>=} 100 GeV) and high-energy (HE; 100 MeV {<=} E {<=} 100 GeV) data from {gamma}-ray observations performed with the H.E.S.S. telescope array and the Fermi-LAT instrument, respectively, are analyzed in order to investigate the non-thermal processes in the starburst galaxy NGC 253. The VHE {gamma}-ray data can be described by a power law in energy with differential photon index {Gamma} = 2.14 {+-} 0.18{sub stat} {+-} 0.30{sub sys} and differential flux normalization at 1 TeV of F{sub 0} = (9.6 {+-} 1.5{sub stat}(+ 5.7, -2.9){sub sys}) Multiplication-Sign 10{sup -14} TeV{sup -1} cm{sup -2} s{sup -1}. A power-law fit to the differential HE {gamma}-ray spectrum reveals a photon index of {Gamma} 2.24 {+-} 0.14{sub stat} {+-} 0.03{sub sys} and an integral flux between 200 MeV and 200 GeV of F(0.2-200 GeV) = (4.9 {+-} 1.0{sub stat} {+-} 0.3{sub sys}) Multiplication-Sign 10{sup -9} cm{sup -2} s{sup -1}. No evidence for a spectral break or turnover is found over the dynamic range of both the LAT instrument and the H.E.S.S. experiment: a combined fit of a power law to the HE and VHE {gamma}-ray data results in a differential photon index {Gamma} = 2.34 {+-} 0.03 with a p-value of 30%. The {gamma}-ray observations indicate that at least about 20% of the energy of the cosmic rays (CRs) capable of producing hadronic interactions is channeled into pion production. The smooth alignment between the spectra in the HE and VHE {gamma}-ray domain suggests that the same transport processes dominate in the entire energy range. Advection is most likely responsible for charged particle removal from the starburst nucleus from GeV to multiple TeV energies. In a hadronic scenario for the {gamma}-ray production, the single overall power-law spectrum observed would therefore correspond to the mean energy spectrum produced by the ensemble of CR sources in the starburst region.

  13. On-line neutron capture gamma analysis with a Ge detector

    NASA Astrophysics Data System (ADS)

    Uusitalo, Seppo; Lukander, Tuula

    Semiconductor gamma detectors are practicable in on-line neutron capture gamma ray analysis of ore concentrates, when heavy water and graphite are used as moderators. A suitable moderator geometry was found using Monte Carlo simulation. An experimental system was constructed and used to measure copper and nickel concentrate samples taken from the feed of a flash smelting furnace.

  14. DISENTANGLING HADRONIC AND LEPTONIC CASCADE SCENARIOS FROM THE VERY-HIGH-ENERGY GAMMA-RAY EMISSION OF DISTANT HARD-SPECTRUM BLAZARS

    SciTech Connect

    Takami, Hajime; Murase, Kohta; Dermer, Charles D. E-mail: murase@ias.edu

    2013-07-10

    Recent data from the Fermi Large Area Telescope have revealed about a dozen distant hard-spectrum blazars that have very-high-energy (VHE; {approx}> 100 GeV) photons associated with them, but most of them have not yet been detected by imaging atmospheric Cherenkov Telescopes. Most of these high-energy gamma-ray spectra, like those of other extreme high-frequency peaked BL Lac objects, can be well explained either by gamma rays emitted at the source or by cascades induced by ultra-high-energy cosmic rays, as we show specifically for KUV 00311-1938. We consider the prospects for detection of the VHE sources by the planned Cherenkov Telescope Array (CTA) and show how it can distinguish the two scenarios by measuring the integrated flux above {approx}500 GeV (depending on source redshift) for several luminous sources with z {approx}< 1 in the sample. Strong evidence for the origin of ultra-high-energy cosmic rays could be obtained from VHE observations with CTA. Depending on redshift, if the often quoted redshift of KUV 00311-1938 (z = 0.61) is believed, then preliminary H.E.S.S. data favor cascades induced by ultra-high-energy cosmic rays. Accurate redshift measurements of hard-spectrum blazars are essential for this study.

  15. The soft gamma-ray spectrum of A0535+26: Detection of an absorption feature at 110 keV by OSSE

    NASA Technical Reports Server (NTRS)

    Grove, J. E.; Strickman, M. S.; Johnson, W. N.; Kurfess, J. D.; Kinzer, R. L.; Starr, C. H.; Jung, G. V.; Kendziorra, E.; Maisack, M.; Staubert, R.

    1995-01-01

    We present soft gamma-ray observations by the Oriented Scintillation Spectrometer Experiment (OSSE) on the Compton Gamma Ray Observatory (GRO) of the transient X-ray binary pulsar A0535+26. The observations were made 1994 February 8-17, immediately prior to the peak of a giant outburst. The phase averaged spectrum is complex and cannot be described by a single-component model. We find that structure in the spectrum above 100 keV can best be modeled by an absorption feature near 110 keV, which we interepret as the signature of cyclotron resonant scattering. Because of OSSE's 45 keV threshold, we are unable to make a definitive statement on the presence of a 55 keV absorption line; however, we can conclude that if this line does exist, it must have a smaller optical depth than the line at 110 keV. A first harmonic (=fundamental) cyclotron resonance at 110 keV corresponds to a magnetic field strength at the surface of the neutron star of approximately 1 x 10(exp 13) G (approximately 5 x 10(exp 12) G if the first harmonic is at 55 keV).

  16. Impaired gamma-band activity during perceptual organization in adults with autism spectrum disorders: evidence for dysfunctional network activity in frontal-posterior cortices.

    PubMed

    Sun, Limin; Grützner, Christine; Bölte, Sven; Wibral, Michael; Tozman, Tahmine; Schlitt, Sabine; Poustka, Fritz; Singer, Wolf; Freitag, Christine M; Uhlhaas, Peter J

    2012-07-11

    Current theories of the pathophysiology of autism spectrum disorders (ASD) have focused on abnormal temporal coordination of neural activity in cortical circuits as a core impairment of the disorder. In the current study, we examined the possibility that gamma-band activity may be crucially involved in aberrant brain functioning in ASD. Magneto-encephalographic (MEG) data were recorded from 13 adult human participants with ASD and 16 controls during the presentation of Mooney faces. MEG data were analyzed in the 25-150 Hz frequency range and a beamforming approach was used to identify the sources of spectral power. Participants with ASD showed elevated reaction times and reduced detection rates during the perception of upright Mooney faces, while responses to inverted stimuli were in the normal range. Impaired perceptual organization in the ASD group was accompanied by a reduction in both the amplitude and phase locking of gamma-band activity. A beamforming approach identified distinct networks during perceptual organization in controls and participants with ASD. In controls, perceptual organization of Mooney faces involved increased 60-120 Hz activity in a frontoparietal network, while in the ASD group stronger activation was found in visual regions. These findings highlight the contribution of impaired gamma-band activity toward complex visual processing in ASD, suggesting atypical modulation of high-frequency power in frontoposterior networks.

  17. Hydrogen spectrum in magnetic white dwarfs - H-alpha, H-beta and H-gamma transitions

    NASA Technical Reports Server (NTRS)

    Henry, R. J. W.; Oconnell, R. F.

    1985-01-01

    Using the results of an accurate variational calculation, a graphical display of the wavelengths of the H-alpha H-beta, and H-gamma lines of hydrogen for magnetic field values ranging from 0 to 560 megagauss, which is believed to cover the range of fields found in magnetic white dwarfs. This is the first complete detailed compilation of such results.

  18. Evaluating Acupuncture Point and Nonacupuncture Point Stimulation with EEG: A High-Frequency Power Spectrum Analysis

    PubMed Central

    Choi, Kwang-Ho; Cho, Seong Jin; Kang, Suk-Yun; Ahn, Seong Hun

    2016-01-01

    To identify physical and sensory responses to acupuncture point stimulation (APS), nonacupuncture point stimulation (NAPS) and no stimulation (NS), changes in the high-frequency power spectrum before and after stimulation were evaluated with electroencephalography (EEG). A total of 37 healthy subjects received APS at the LI4 point, NAPS, or NS with their eyes closed. Background brain waves were measured before, during, and after stimulation using 8 channels. Changes in the power spectra of gamma waves and high beta waves before, during, and after stimulation were comparatively analyzed. After NAPS, absolute high beta power (AHBP), relative high beta power (RHBP), absolute gamma power (AGP), and relative gamma power (RGP) tended to increase in all channels. But no consistent notable changes were found for APS and NS. NAPS is believed to cause temporary reactions to stress, tension, and sensory responses of the human body, while APS responds stably compared to stimulation of other parts of the body.

  19. Roller element bearing fault diagnosis using singular spectrum analysis

    NASA Astrophysics Data System (ADS)

    Muruganatham, Bubathi; Sanjith, M. A.; Krishnakumar, B.; Satya Murty, S. A. V.

    2013-02-01

    Most of the existing time series methods of feature extraction involve complex algorithm and the extracted features are affected by sample size and noise. In this paper, a simple time series method for bearing fault feature extraction using singular spectrum analysis (SSA) of the vibration signal is proposed. The method is easy to implement and fault feature is noise immune. SSA is used for the decomposition of the acquired signals into an additive set of principal components. A new approach for the selection of the principal components is also presented. Two methods of feature extraction based on SSA are implemented. In first method, the singular values (SV) of the selected SV number are adopted as the fault features, and in second method, the energy of the principal components corresponding to the selected SV numbers are used as features. An artificial neural network (ANN) is used for fault diagnosis. The algorithms were evaluated using two experimental datasets—one from a motor bearing subjected to different fault severity levels at various loads, with and without noise, and the other with bearing vibration data obtained in the presence of a gearbox. The effect of sample size, fault size and load on the fault feature is studied. The advantages of the proposed method over the exiting time series method are discussed. The experimental results demonstrate that the proposed bearing fault diagnosis method is simple, noise tolerant and efficient.

  20. THE SPECTRUM AND TERM ANALYSIS OF V II

    SciTech Connect

    Thorne, A. P.; Pickering, J. C.; Semeniuk, J. I.

    2013-07-15

    The spectrum and extended term analysis of V II are presented. Fourier transform spectrometry was used to record high resolution spectra of singly ionized vanadium in the region 1492-5800 A (67020-17260 cm{sup -1}) with vanadium-neon and vanadium-argon hollow cathode lamps as sources. The wavenumber uncertainty for the center of gravity of the strongest lines is typically 0.002 cm{sup -1}, an improvement of an order of magnitude over previous measurements. Most of the lines exhibit partly resolved hyperfine structure. The V II energy levels in the 1985 compilation of Sugar and Corliss have been confirmed and revised, with the exception of the high-lying 4f levels and eight of the lower levels. Thirty-nine of the additional eighty-five high levels published by Iglesias et al. have also been confirmed and revised, and three of their missing levels have been found. The energy uncertainty of the revised levels has been reduced by about an order of magnitude. In total, 176 even levels and 233 odd levels are presented. Wavenumbers and classifications are given for 1242 V II lines.

  1. Mapping Upper Mantle Seismic Discontinuities Using Singular Spectrum Analysis

    NASA Astrophysics Data System (ADS)

    Gu, Y. J.; Dokht, R.; Sacchi, M. D.

    2015-12-01

    Seismic discontinuities are fundamental to the understanding of mantle composition and dynamics. Their depth and impedance are generally determined using secondary seismic phases, most commonly SS precursors and P-to-S converted waves. However, the analysis and interpretation using these approaches often suffer from incomplete data coverage, high noise levels and interfering seismic phases, especially near tectonically complex regions such as subduction zones and continental margins. To overcome these pitfalls, we apply Singular Spectrum Analysis (SSA) to remove random noise, reconstruct missing traces and enhance the robustness of SS precursors and P-to-S conversions from seismic discontinuities. Our method takes advantage of the predictability of time series in frequency-space domain and performs a rank reduction using a singular value decomposition of the trajectory matrix. We apply SSA to synthetic record sections as well as observations of 1) SS precursors beneath the northwestern Pacific subduction zones, and 2) P-to-S converted waves from the Western Canada Sedimentary Basin (WCSB). In comparison with raw or interpolated data, the SSA enhanced reflectivity maps show a greater resolution and a stronger negative correlation between the depths of the 410 and 660 km discontinuities. These effects can be attributed to the suppression of incoherent noise, which tends to reduce the signal amplitude during normal averaging procedures, through rank reduction and the emphasis of principle singular values. Our new results suggest a more laterally coherent 520 km reflection in the western Pacific regions. Similar improvements in data imaging are achieved in western Canada, where strong lateral variations in discontinuity topography are observed in the craton-Cordillera boundary zone. Improvements from SSA relative to conventional approaches are most notable in under-sampled regions.

  2. A Pilot Proteomic Analysis of Salivary Biomarkers in Autism Spectrum Disorder.

    PubMed

    Ngounou Wetie, Armand G; Wormwood, Kelly L; Russell, Stefanie; Ryan, Jeanne P; Darie, Costel C; Woods, Alisa G

    2015-06-01

    Autism spectrum disorder (ASD) prevalence is increasing, with current estimates at 1/68-1/50 individuals diagnosed with an ASD. Diagnosis is based on behavioral assessments. Early diagnosis and intervention is known to greatly improve functional outcomes in people with ASD. Diagnosis, treatment monitoring and prognosis of ASD symptoms could be facilitated with biomarkers to complement behavioral assessments. Mass spectrometry (MS) based proteomics may help reveal biomarkers for ASD. In this pilot study, we have analyzed the salivary proteome in individuals with ASD compared to neurotypical control subjects, using MS-based proteomics. Our goal is to optimize methods for salivary proteomic biomarker discovery and to identify initial putative biomarkers in people with ASDs. The salivary proteome is virtually unstudied in ASD, and saliva could provide an easily accessible biomaterial for analysis. Using nano liquid chromatography-tandem mass spectrometry, we found statistically significant differences in several salivary proteins, including elevated prolactin-inducible protein, lactotransferrin, Ig kappa chain C region, Ig gamma-1 chain C region, Ig lambda-2 chain C regions, neutrophil elastase, polymeric immunoglobulin receptor and deleted in malignant brain tumors 1. Our results indicate that this is an effective method for identification of salivary protein biomarkers, support the concept that immune system and gastrointestinal disturbances may be present in individuals with ASDs and point toward the need for larger studies in behaviorally-characterized individuals.

  3. SER Analysis of MPPM-Coded MIMO-FSO System over Uncorrelated and Correlated Gamma-Gamma Atmospheric Turbulence Channels

    NASA Astrophysics Data System (ADS)

    Khallaf, Haitham S.; Garrido-Balsells, José M.; Shalaby, Hossam M. H.; Sampei, Seiichi

    2015-12-01

    The performance of multiple-input multiple-output free space optical (MIMO-FSO) communication systems, that adopt multipulse pulse position modulation (MPPM) techniques, is analyzed. Both exact and approximate symbol-error rates (SERs) are derived for both cases of uncorrelated and correlated channels. The effects of background noise, receiver shot-noise, and atmospheric turbulence are taken into consideration in our analysis. The random fluctuations of the received optical irradiance, produced by the atmospheric turbulence, is modeled by the widely used gamma-gamma statistical distribution. Uncorrelated MIMO channels are modeled by the α-μ distribution. A closed-form expression for the probability density function of the optical received irradiance is derived for the case of correlated MIMO channels. Using our analytical expressions, the degradation of the system performance with the increment of the correlation coefficients between MIMO channels is corroborated.

  4. The Hadronic Origin of the Hard Gamma-Ray Spectrum from Blazar 1ES 1101-232

    NASA Astrophysics Data System (ADS)

    Cao, Gang; Wang, Jiancheng

    2014-03-01

    The very hard γ-ray spectrum from distant blazars challenges the traditional synchrotron self-Compton (SSC) model, which may indicate that there is a contribution from an additional high-energy component beyond the SSC emission. In this paper, we study the possible origin of the hard γ-ray spectrum from distant blazars. We develop a model to explain the hard γ-ray spectrum from blazar 1ES 1101-232. In the model, the optical and X-ray radiation would come from the synchrotron radiation of primary electrons and secondary pairs and the GeV emission would be produced by the SSC process, however, the hard γ-ray spectrum would originate from the decay of neutral pion produced through proton-photon interactions with the synchrotron radiation photons within the jet. Our model can explain the observed spectral energy distribution of 1ES 1101-232 well, especially the very hard γ-ray spectrum. However, our model requires a very large proton power to efficiently produce the γ-ray through proton-photon interactions.

  5. The hadronic origin of the hard gamma-ray spectrum from blazar 1ES 1101-232

    SciTech Connect

    Cao, Gang; Wang, Jiancheng E-mail: jcwang@ynao.ac.cn

    2014-03-10

    The very hard γ-ray spectrum from distant blazars challenges the traditional synchrotron self-Compton (SSC) model, which may indicate that there is a contribution from an additional high-energy component beyond the SSC emission. In this paper, we study the possible origin of the hard γ-ray spectrum from distant blazars. We develop a model to explain the hard γ-ray spectrum from blazar 1ES 1101-232. In the model, the optical and X-ray radiation would come from the synchrotron radiation of primary electrons and secondary pairs and the GeV emission would be produced by the SSC process, however, the hard γ-ray spectrum would originate from the decay of neutral pion produced through proton-photon interactions with the synchrotron radiation photons within the jet. Our model can explain the observed spectral energy distribution of 1ES 1101-232 well, especially the very hard γ-ray spectrum. However, our model requires a very large proton power to efficiently produce the γ-ray through proton-photon interactions.

  6. Pulsar and diffuse contributions to the observed galactic gamma radiation

    NASA Technical Reports Server (NTRS)

    Harding, A. K.; Stecker, F. W.

    1980-01-01

    With the acquisition of satellite data on the energy spectrum of galactic gamma-radiation, it is clear that such radiation has a multicomponent nature. A calculation of the pulsar gamma ray emission spectrum is used together with a statistical analysis of recent data on 328 known pulsars to make a new determination of the pulsar contribution to galactic gamma ray emission. The contributions from diffuse interstellar cosmic ray induced production mechanisms to the total emission are then reexamined. It is concluded that pulsars may account for a significant fraction of galactic gamma ray emission.

  7. The expected high-energy to ultra-high-energy gamma-ray spectrum of the Crab Nebula

    NASA Technical Reports Server (NTRS)

    De Jager, O. C.; Harding, A. K.

    1992-01-01

    The inverse Compton scattering model for the unpulsed TeV emission from the Crab Nebula is reexamined using the magnetic field distribution derived from MHD flow models of the nebula. It is shown that the observed flux can be explained if the average nebular field is indeed about 0.0003, as is predicted by the spectral break between radio and optical. The brightness distribution of the TeV gamma-ray signal is expected to extend out to about 1.5 arcmin from the pulsar. The present estimates predict a steady flux of unpulsed ultrahigh-energy gamma-rays due to the inverse Compton scattering of soft photons by shock-accelerated electrons and/or positrons in the vicinity of the shock.

  8. Measurement and Analysis of Gamma-Rays Emitted From Spent Nuclear Fuel Above 3 MeV

    SciTech Connect

    Rodriguez, Douglas C.; Anderson, Elaina R.; Anderson, Kevin K.; Campbell, Luke W.; Fast, James E.; Jarman, Kenneth D.; Kulisek, Jonathan A.; Orton, Christopher R.; Runkle, Robert C.; Stave, Sean C.

    2013-12-01

    The gamma-ray spectrum of spent nuclear fuel in the 3- to 6-MeV energy range is important for active interrogation since emitted gamma rays emitted from nuclear decay are not expected to interfere with measurements in this energy region. There is, unfortunately, a dearth of empirical measurements from spent nuclear fuel in this region. This work is an initial attempt to partially ll this gap by presenting an analysis of gamma-ray spectra collected from a set of spent nuclear fuel sources using a high-purity germanium detector array. This multi-crystal array possesses a large collection volume, providing high energy resolution up to 16 MeV. The results of these measurements establish the continuum count-rate in the energy region between 3- and 6-MeV. Also assessed is the potential for peaks from passive emissions to interfere with peak measurements resulting from active interrogation delayed emissions. As one of the first documented empirical measurements of passive emissions from spent fuel for energies above 3 MeV, this work provides a foundation for active interrogation model validation and detector development.

  9. Lunar elemental analysis obtained from the Apollo gamma-ray and X-ray remote sensing experiment

    NASA Technical Reports Server (NTRS)

    Trombka, J. I.; Arnold, J. R.; Adler, I.; Metzger, A. E.; Reedy, R. C.

    1977-01-01

    Gamma-ray and X-ray spectrometers carried in the service modules of the Apollo 15 and Apollo 16 spacecraft were employed for compositional mapping of the lunar surface. The measurements involved the observation of the intensity and characteristic energy distribution of gamma rays and X-rays emitted from the lunar surface. A large-scale compositional map of over 10 percent of the lunar surface was obtained from an analysis of the observed spectra. The objective of the X-ray experiment was to measure the K spectral lines from Mg, Al, and Si. Spectra were obtained and the data were reduced to Al/Si and Mg/Si intensity ratios and ultimately to chemical ratios. Analyses of the results have indicated (1) that the Al/Si ratios are highest in the lunar highlands and considerably lower in the maria, and (2) that the Mg/Si concentrations generally show the opposite relationship. The objective of the gamma-ray experiment was to measure the natural and cosmic-ray-induced activity emission spectrum. At this time, the elemental abundances for Th, U, K, Fe, Ti, Si, and O have been determined over a number of major lunar regions. Regions of relatively high natural radioactivity were found in the Mare Imbrium and Oceanus Procellarum regions.

  10. Measurement and analysis of gamma-rays emitted from spent nuclear fuel above 3 MeV.

    PubMed

    Rodriguez, Douglas C; Anderson, Elaina; Anderson, Kevin K; Campbell, Luke W; Fast, James E; Jarman, Kenneth; Kulisek, Jonathan; Orton, Christopher R; Runkle, Robert C; Stave, Sean

    2013-12-01

    The gamma-ray spectrum of spent nuclear fuel in the 3-6 MeV energy range is important for active interrogation since gamma rays emitted from nuclear decay are not expected to interfere with measurements in this energy region. There is, unfortunately, a dearth of empirical measurements from spent nuclear fuel in this region. This work is an initial attempt to partially fill this gap by presenting an analysis of gamma-ray spectra collected from a set of spent nuclear fuel sources using a high-purity germanium detector array. This multi-crystal array possesses a large collection volume, providing high energy resolution up to 16 MeV. The results of these measurements establish the continuum count-rate in the energy region between 3 and 6 MeV. Also assessed is the potential for peaks from passive emissions to interfere with peak measurements resulting from active interrogation delayed emissions. As one of the first documented empirical measurements of passive emissions from spent fuel for energies above 3 MeV, this work provides a foundation for active interrogation model validation and detector development. PMID:24035928

  11. Enhanced lines and box-shaped features in the gamma-ray spectrum from annihilating dark matter in the NMSSM

    NASA Astrophysics Data System (ADS)

    Cerdeño, D. G.; Peiró, M.; Robles, S.

    2016-04-01

    We study spectral features in the gamma-ray emission from dark matter (DM) annihilation in the Next-to-Minimal Supersymmetric Standard Model (NMSSM), with either neutralino or right-handed (RH) sneutrino DM . We perform a series of scans over the NMSSM parameter space, compute the DM annihilation cross section into two photons and the contribution of box-shaped features, and compare them with the limits derived from the Fermi-LAT search for gamma-ray lines using the latest Pass 8 data. We implement the LHC bounds on the Higgs sector and on the masses of supersymmetric particles as well as the constraints on low-energy observables. We also consider the recent upper limits from the Fermi-LAT satellite on the continuum gamma-ray emission from dwarf spheroidal galaxies (dSphs). We show that in the case of the RH sneutrino the constraint on gamma-ray spectral features can be more stringent than the dSph bounds. This is due to the Breit-Wigner enhancement near the ubiquitous resonances with a CP even Higgs and the contribution of scalar and pseudoscalar Higgs final states to box-shaped features. By contrast, for neutralino DM, the di-photon final state is only enhanced in the resonance with a Z boson and box-shaped features are even more suppressed. Therefore, the observation of spectral features could constitute a discriminating factor between both models. In addition, we compare our results with direct DM searches, including the SuperCDMS and LUX limits on the elastic DM-nucleus scattering cross section and show that some of these scenarios would be accessible to next generation experiments. Thus, our findings strengthen the idea of complementarity among distinct DM search strategies.

  12. Spectrum analysis techniques for personnel detection using seismic sensors

    NASA Astrophysics Data System (ADS)

    Houston, Kenneth M.; McGaffigan, Daniel P.

    2003-09-01

    There is a general need for improved detection range and false alarm performance for seismic sensors used for personnel detection. In this paper we describe a novel footstep detection algorithm which was developed and run on seismic footstep data collected at the Aberdeen Proving Ground in December 2000. The initial focus was an assessment of achievable detection range. The conventional approach to footstep detection is to detect transients corresponding to individual footfalls. We feel this is an error-prone approach. Because many real-world signals unrelated to human locomotion look like transients, transient-based footstep detection will inevitably either suffer from high false alarm rates or will be insensitive. Instead, we examined the use of spectrum analysis on envelope-detected seismic signals and have found the general method to be quite promising, not only for detection, but also for discrimination against other types of seismic sources. In particular, gait patterns and their corresponding signatures may help discriminate between human intruders and animals. In the APG data set, mean detection ranges of 64 meters (at PD=50%) were observed for normal walking, significantly improving on ranges previously reported. For running, mean detection ranges of 84 meters were observed. However, stealthy walking (creeping) remains a considerable problem. Even at short ranges (10 meters), in some cases the detection rate was less than 50%. In future efforts, additional data sets for a range of geologic and environmental conditions should be acquired and analyzed. Improvements to the detection algorithms are possible, including estimation of direction of travel and the number of intruders.

  13. Analysis of X chromosome inactivation in autism spectrum disorders

    PubMed Central

    Gong, Xiaohong; Bacchelli, Elena; Blasi, Francesca; Toma, Claudio; Betancur, Catalina; Chaste, Pauline; Delorme, Richard; Durand, Christelle; Fauchereau, Fabien; Botros, Hany Goubran; Leboyer, Marion; Mouren-Simeoni, Marie-Christine; Nygren, Gudrun; Anckarsäter, Henrik; Rastam, Maria; Gillberg, I Carina; Gillberg, Christopher; Moreno-De-Luca, Daniel; Carone, Simona; Nummela, Ilona; Rossi, Mari; Battaglia, Agatino; Jarvela, Irma; Maestrini, Elena; Bourgeron, Thomas

    2008-01-01

    Autism spectrum disorders (ASD) are complex genetic disorders more frequently observed in males. Skewed X chromosome inactivation (XCI) is observed in heterozygous females carrying gene mutations involved in several X-linked syndromes. In this study, we aimed to estimate the role of X-linked genes in the susceptibility to ASD by ascertaining the XCI pattern in a sample of 543 informative mothers of children with ASD and in a sample of 163 affected girls. The XCI pattern was also determined in two control groups (144 adult females and 40 young females) with a similar age distribution to the mothers sample and affected girls sample, respectively. We observed no significant excess of skewed XCI in families with ASD. Interestingly, two mothers and one girl carrying known mutations in X-linked genes (NLGN3, ATRX, MECP2) showed highly skewed XCI, suggesting that ascertainment of XCI could reveal families with X-linked mutations. Linkage analysis was carried out in the subgroup of multiplex families with skewed XCI (80:20) and a modest increased allele sharing was obtained in the Xq27-Xq28 region, with a peak Z-score of 1.75 close to rs719489. In summary, our results suggest that there is no major X-linked gene subject to XCI and expressed in blood cells conferring susceptibility to ASD. However, the possibility that rare mutations in X-linked genes could contribute to ASD cannot be excluded. We propose that the XCI profile could be a useful criteria to prioritize families for mutation screening of X-linked candidate genes. PMID:18361425

  14. Improved neutron-gamma discrimination for a 6Li-glass neutron detector using digital signal analysis methods

    DOE PAGES

    Wang, Cai -Lin; Riedel, Richard A.

    2016-01-14

    A 6Li-glass scintillator (GS20) based neutron Anger camera was developed for time-of-flight single-crystal diffraction instruments at SNS. Traditional pulse-height analysis (PHA) for neutron-gamma discrimination (NGD) resulted in the neutron-gamma efficiency ratio (defined as NGD ratio) on the order of 104. The NGD ratios of Anger cameras need to be improved for broader applications including neutron reflectometers. For this purpose, five digital signal analysis methods of individual waveforms from PMTs were proposed using: i). pulse-amplitude histogram; ii). power spectrum analysis combined with the maximum pulse amplitude; iii). two event parameters (a1, b0) obtained from Wiener filter; iv). an effective amplitude (m)more » obtained from an adaptive least-mean-square (LMS) filter; and v). a cross-correlation (CC) coefficient between an individual waveform and a reference. The NGD ratios can be 1-102 times those from traditional PHA method. A brighter scintillator GS2 has better NGD ratio than GS20, but lower neutron detection efficiency. The ultimate NGD ratio is related to the ambient, high-energy background events. Moreover, our results indicate the NGD capability of neutron Anger cameras can be improved using digital signal analysis methods and brighter neutron scintillators.« less

  15. Improved neutron-gamma discrimination for a (6)Li-glass neutron detector using digital signal analysis methods.

    PubMed

    Wang, C L; Riedel, R A

    2016-01-01

    A (6)Li-glass scintillator (GS20) based neutron Anger camera was developed for time-of-flight single-crystal diffraction instruments at Spallation Neutron Source. Traditional Pulse-Height Analysis (PHA) for Neutron-Gamma Discrimination (NGD) resulted in the neutron-gamma efficiency ratio (defined as NGD ratio) on the order of 10(4). The NGD ratios of Anger cameras need to be improved for broader applications including neutron reflectometers. For this purpose, six digital signal analysis methods of individual waveforms acquired from photomultiplier tubes were proposed using (i) charge integration, (ii) pulse-amplitude histograms, (iii) power spectrum analysis combined with the maximum pulse-amplitude, (iv) two event parameters (a1, b0) obtained from a Wiener filter, (v) an effective amplitude (m) obtained from an adaptive least-mean-square filter, and (vi) a cross-correlation coefficient between individual and reference waveforms. The NGD ratios are about 70 times those from the traditional PHA method. Our results indicate the NGD capabilities of neutron Anger cameras based on GS20 scintillators can be significantly improved with digital signal analysis methods. PMID:26827314

  16. Improved neutron-gamma discrimination for a 6Li-glass neutron detector using digital signal analysis methods

    NASA Astrophysics Data System (ADS)

    Wang, C. L.; Riedel, R. A.

    2016-01-01

    A 6Li-glass scintillator (GS20) based neutron Anger camera was developed for time-of-flight single-crystal diffraction instruments at Spallation Neutron Source. Traditional Pulse-Height Analysis (PHA) for Neutron-Gamma Discrimination (NGD) resulted in the neutron-gamma efficiency ratio (defined as NGD ratio) on the order of 104. The NGD ratios of Anger cameras need to be improved for broader applications including neutron reflectometers. For this purpose, six digital signal analysis methods of individual waveforms acquired from photomultiplier tubes were proposed using (i) charge integration, (ii) pulse-amplitude histograms, (iii) power spectrum analysis combined with the maximum pulse-amplitude, (iv) two event parameters (a1, b0) obtained from a Wiener filter, (v) an effective amplitude (m) obtained from an adaptive least-mean-square filter, and (vi) a cross-correlation coefficient between individual and reference waveforms. The NGD ratios are about 70 times those from the traditional PHA method. Our results indicate the NGD capabilities of neutron Anger cameras based on GS20 scintillators can be significantly improved with digital signal analysis methods.

  17. Analysis of the p p-bar mass spectrum in J/Psi

    SciTech Connect

    J. Haidenbauer; S. Krewald; U.-G. Meissner; A. Sibirtsev; A. W. Thomas

    2005-05-16

    The near-threshold enhancement in the p p-bar invariant mass spectrum of the reaction J/Psi --> gamma p p-bar, observed in an experiment by the BES Collaboration, is analysed. It is shown, within the Watson-Migdal approach to final state interactions, that the mass dependence of the p p-bar spectrum close to the threshold can be reproduced by the S-wave p p-bar interaction of the Jülich N N-bar model in the isospin I=1 state. Difficulties in the consistent interpretation of the p invariant mass spectrum of the reaction J/Psi --> pi^0 p p-bar, where there are no obvious signs for a final state interaction, are discussed.

  18. Digital discrimination of neutrons and gamma-rays in organic scintillation detectors using moment analysis

    SciTech Connect

    Xie Xufei; Zhang Xing; Yuan Xi; Chen Jinxiang; Li Xiangqing; Zhang Guohui; Fan Tieshuan; Yuan Guoliang; Yang Jinwei; Yang Qingwei

    2012-09-15

    Digital discrimination of neutron and gamma-ray events in an organic scintillator has been investigated by moment analysis. Signals induced by an americium-beryllium (Am/Be) isotropic neutron source in a stilbene crystal detector have been sampled with a flash analogue-to-digital converter (ADC) of 1 GSamples/s sampling rate and 10-bit vertical resolution. Neutrons and gamma-rays have been successfully discriminated with a threshold corresponding to gamma-ray energy about 217 keV. Moment analysis has also been verified against the results assessed by a time-of-flight (TOF) measurement. It is shown that the classification of neutrons and gamma-rays afforded by moment analysis is consistent with that achieved by digital TOF measurement. This method has been applied to analyze the data acquired from the stilbene crystal detector in mixed radiation field of the HL-2A tokamak deuterium plasma discharges and the results are described.

  19. Digital discrimination of neutrons and gamma-rays in organic scintillation detectors using moment analysis

    NASA Astrophysics Data System (ADS)

    Xie, Xufei; Zhang, Xing; Yuan, Xi; Chen, Jinxiang; Li, Xiangqing; Zhang, Guohui; Fan, Tieshuan; Yuan, Guoliang; Yang, Jinwei; Yang, Qingwei

    2012-09-01

    Digital discrimination of neutron and gamma-ray events in an organic scintillator has been investigated by moment analysis. Signals induced by an americium-beryllium (Am/Be) isotropic neutron source in a stilbene crystal detector have been sampled with a flash analogue-to-digital converter (ADC) of 1 GSamples/s sampling rate and 10-bit vertical resolution. Neutrons and gamma-rays have been successfully discriminated with a threshold corresponding to gamma-ray energy about 217 keV. Moment analysis has also been verified against the results assessed by a time-of-flight (TOF) measurement. It is shown that the classification of neutrons and gamma-rays afforded by moment analysis is consistent with that achieved by digital TOF measurement. This method has been applied to analyze the data acquired from the stilbene crystal detector in mixed radiation field of the HL-2A tokamak deuterium plasma discharges and the results are described.

  20. Gamma radiological surveys of the Oak Ridge Reservation, Paducah Gaseous Diffusion Plant, and Portsmouth Gaseous Diffusion Plant, 1990-1993, and overview of data processing and analysis by the Environmental Restoration Remote Sensing Program, Fiscal Year 1995

    SciTech Connect

    Smyre, J.L.; Moll, B.W.; King, A.L.

    1996-06-01

    Three gamma radiological surveys have been conducted under auspices of the ER Remote Sensing Program: (1) Oak Ridge Reservation (ORR) (1992), (2) Clinch River (1992), and (3) Portsmouth Gaseous Diffusion Plant (PORTS) (1993). In addition, the Remote Sensing Program has acquired the results of earlier surveys at Paducah Gaseous Diffusion Plant (PGDP) (1990) and PORTS (1990). These radiological surveys provide data for characterization and long-term monitoring of U.S. Department of Energy (DOE) contamination areas since many of the radioactive materials processed or handled on the ORR, PGDP, and PORTS are direct gamma radiation emitters or have gamma emitting daughter radionuclides. High resolution airborne gamma radiation surveys require a helicopter outfitted with one or two detector pods, a computer-based data acquisition system, and an accurate navigational positioning system for relating collected data to ground location. Sensors measure the ground-level gamma energy spectrum in the 38 to 3,026 KeV range. Analysis can provide gamma emission strength in counts per second for either gross or total man-made gamma emissions. Gross count gamma radiation includes natural background radiation from terrestrial sources (radionuclides present in small amounts in the earth`s soil and bedrock), from radon gas, and from cosmic rays from outer space as well as radiation from man-made radionuclides. Man-made count gamma data include only the portion of the gross count that can be directly attributed to gamma rays from man-made radionuclides. Interpretation of the gamma energy spectra can make possible the determination of which specific radioisotopes contribute to the observed man-made gamma radiation, either as direct or as indirect (i.e., daughter) gamma energy from specific radionuclides (e.g., cesium-137, cobalt-60, uranium-238).

  1. The Marshall Space Flight Center Development of Mirror Modules for the ART-XC Ins1rument Aboard the Spectrum-Roentgen-Gamma Mission

    NASA Technical Reports Server (NTRS)

    Gubarev, M.; Ramsey, B.; ODell, S. L.; Elsner, R.; Kilaru, K.; McCracken, J.; Pavlinsky, M.; Tkachenko, A.; Lapshov, I.

    2012-01-01

    The Spectrum-Rontgen-Gamma (SRG) mission is a Russian-German X-ray astrophysical observatory that carries two co-aligned and complementary X-ray telescope systems. The primary instrument is the German-led extended ROentgen Survey with an Imaging Telescope Array (eROSITA), a 7-module X-ray telescope system that covers the energy range from 0.2-12 keV. The complementary instrument is the Russian-led Astronomical Roentgen Telescope -- X-ray Concentrator (ART-XC or ART), a 7-module X-ray telescope system that provides higher energy coverage, up to 30 keV (with limited sensitivity above 12 keV).

  2. The Marshall Space Flight Center Development of Mirror Modules for the ART-XC Instrument aboard the Spectrum-Roentgen-Gamma Mission

    NASA Technical Reports Server (NTRS)

    Gubarev, Mikhail V.; Ramsey, B.; ODell, S. L.; Elsner, R.; Kilaru, K.; McCracken, J.; Pavlinsky, M.; Tkachenko, A.; Lapshov, I.

    2012-01-01

    The Marshall Space Flight Center (MSFC) is developing x-ray mirror modules for the ART-XC instrument on board the Spectrum-Roentgen Gamma Mission under a Reimbursable Agreement between NASA and the Russian Space Research Institute (IKI.) ART-XC will consist of seven co-aligned x-ray mirror modules with seven corresponding CdTe focal plane detectors. Currently, four of the modules are being fabricated by the Marshall Space Flight Center (MSFC.) Each MSFC module consist of 28 nested Ni/Co thin shells giving an effective area of 65 sq cm at 8 keV, response out to 30 keV, and an angular resolution of 45 arcsec or better HPD. Delivery of these modules to the IKI is scheduled for summer 2013. We present a status of the ART x-ray modules development at the MSFC.

  3. Improvement of the edge rotation diagnostic spectrum analysis via simulation

    SciTech Connect

    Luo, J.; Zhuang, G. Cheng, Z. F.; Zhang, X. L.; Hou, S. Y.; Cheng, C.

    2014-11-15

    The edge rotation diagnostic (ERD) system has been developed on the Joint Texas Experimental Tokamak to measure the edge toroidal rotation velocity by observing the shifted wavelength of carbon V (C V 227.09 nm). Since the measured spectrum is an integrated result along the viewing line from the plasma core to the edge, a method via simulation has been developed to analyze the ERD spectrum. With the necessary parameters such as C V radiation profile and the ion temperature profile, a local rotation profile at the normalized minor radius of 0.5-1 is obtained.

  4. Improvement of the edge rotation diagnostic spectrum analysis via simulationa)

    NASA Astrophysics Data System (ADS)

    Luo, J.; Zhuang, G.; Cheng, Z. F.; Zhang, X. L.; Hou, S. Y.; Cheng, C.

    2014-11-01

    The edge rotation diagnostic (ERD) system has been developed on the Joint Texas Experimental Tokamak to measure the edge toroidal rotation velocity by observing the shifted wavelength of carbon V (C V 227.09 nm). Since the measured spectrum is an integrated result along the viewing line from the plasma core to the edge, a method via simulation has been developed to analyze the ERD spectrum. With the necessary parameters such as C V radiation profile and the ion temperature profile, a local rotation profile at the normalized minor radius of 0.5-1 is obtained.

  5. Impact of gamma analysis parameters on dose evaluation using Gafchromic EBT2 films

    NASA Astrophysics Data System (ADS)

    Lee, Seu-Ran; Park, Ji-Yeon; Suh, Tae-Suk; Park, Hae-Jin; Lee, Jeong-Woo; Jung, Won-Gyun

    2012-10-01

    To recommend optimal gamma analysis parameters (grid size and search range) for detecting dose errors, we evaluated the impact of gamma models and parameters on dose verification in volumetric modulated fields. Delivered doses were verified under open, 45° wedged, and volumetric modulated fields for prostate, anal, head and neck, and brain cancer by using Gafchromic EBT2 films for gamma evaluation. Two gamma models (a conventional method and a modified method to compensate for unintended dose errors caused by misalignments between reference and evaluated matrixes) were employed. The variation in the detected dose errors was evaluated in each gamma model for different grid sizes (0.5, 1, and 2 mm) and search ranges (1, 2, and 4 mm) applied to determine distant-to-agreement. The dose discrepancy of each evaluation was qualitatively and quantitatively evaluated using a pass ratio in analysis software developed in-house. The modified gamma model with a small search range and grid size showed a higher pass ratio than the conventional model in volumetric modulated arc therapy. The pass ratio for 2 mm grid size decreased by over 40% as compared to that for 1 mm grid size. The pass ratio decreased by more than 30% as the search range was increased from 1 mm to 4 mm. Therefore, 1 mm grid size and 1 mm search range may be appropriate to evaluate dose errors in modulated fields after using the modified gamma model.

  6. A Gamma-Ray Burst/Pulsar for Cosmic Ray Positrons with a Dark Matter-Like Spectrum

    NASA Astrophysics Data System (ADS)

    Ioka, K.

    2010-04-01

    We propose that a nearby gamma-ray burst (GRB) or GRB-like (old, single, and short-lived) pulsar, supernova remnant, or microquasar about 10^{5-6} years ago may be responsible for the excesses of cosmic ray positrons and electrons recently observed in the PAMELA, ATIC/PPB-BETS, Fermi, and HESS experiments. We can reproduce the smooth Fermi/HESS spectra as well as the spiky ATIC/PPB-BETS spectra. The spectra have a sharp cutoff that is similar to the dark matter predictions, sometimes together with a line (not similar), since high-energy cosmic rays cool fast where the cutoff/line energy marks the source age. A GRB-like astrophysical source is expected to have a small but finite spread in the cutoff/line as well as anisotropy in the cosmic ray and diffuse gamma-ray flux, providing a method for the Fermi and future CALET experiments to discriminate between dark matter and astrophysical origins.

  7. VizieR Online Data Catalog: The cosmic TeV gamma-ray background spectrum (Inoue+, 2016)

    NASA Astrophysics Data System (ADS)

    Inoue, Y.; Tanaka, Y. T.

    2016-05-01

    We select 35 known extragalactic TeV sources which are located at Galactic latitude |b|>=10° and whose low activity state flux is available, since our aim is to give conservative constraints on the total cosmic gamma-ray background (CGB) in the TeV band. For each source, we select the lowest fluxes among several TeV measurements by modern imaging atmospheric Cherenkov telescopes (IACTs; H.E.S.S., MAGIC, and VERITAS) and further restrict samples showing no significant variability in the TeV band during observations. The sample contains 30 blazars, 3 radio galaxies, and 2 starburst galaxies from the default TeVcat catalog (Wakely & Horan 2008ICRC....3.1341W) which include published sources only. We also include the Fermi third source (3FGL) catalog data (Acero et al. 2015, J/ApJS/218/23) to cover GeV gamma-ray spectra. The 3FGL catalog is based on its first 48 months of survey data. All of our sample have counterparts in the 3FGL catalog. (2 data files).

  8. Analysis of Data from the Transient Gamma-Ray Spectrometer Experiment on the GGS/Wind Spacecraft

    NASA Technical Reports Server (NTRS)

    Hurley, K.

    1997-01-01

    The data analysis from the TGRS experiment is continuing, although the UC Berkeley PI, K. Hurley, is no longer funded for this effort. This experiment has been returning data on the energy spectra and time histories of cosmic gamma-ray bursts since November 1994, and continues to operate in good health. Over a 3 year period ending in November 1997, 41 bursts have been detected simultaneously by TGRS and Dr. Hurley's Ulysses gamma-ray burst experiment. By comparing the times of arrival of a burst at Ulysses and TGRS, we can obtain an annulus of arrival directions for the event. Typical 3sigma annulus widths range from several arcminutes to tens of arcminutes. Because the WIND spacecraft is as far as several light-seconds from Earth, it is sometimes possible to obtain a second annulus using the Burst and Transient Source Experiment (BATSE) aboard the GRO spacecraft. 23 of the 41 bursts were also observed by this experiment. Generally, the two annuli intersect at grazing incidence, leading to a long, narrow error box which reduces somewhat the error circles obtained from BATSE alone. Table 1 summarizes the burst data from TGRS. We plan to defer the publication of these locations until a larger number of events has been accumulated. Measuring the energy spectra of cosmic gamma-ray bursts to search for line emission is one of the prime objectives of this experiment. However, an intense gamma-ray burst is required, or the statistics become too weak to draw meaningful conclusions. One such event has occurred to date, on August 22, 1995, and we have examined it in detail. The spectrum shows no evidence for lines, however.

  9. The fractal energy measurement and the singularity energy spectrum analysis

    NASA Astrophysics Data System (ADS)

    Xiong, Gang; Zhang, Shuning; Yang, Xiaoniu

    2012-12-01

    The singularity exponent (SE) is the characteristic parameter of fractal and multifractal signals. Based on SE, the fractal dimension reflecting the global self-similar character, the instantaneous SE reflecting the local self-similar character, the multifractal spectrum (MFS) reflecting the distribution of SE, and the time-varying MFS reflecting pointwise multifractal spectrum were proposed. However, all the studies were based on the depiction of spatial or differentiability characters of fractal signals. Taking the SE as the independent dimension, this paper investigates the fractal energy measurement (FEM) and the singularity energy spectrum (SES) theory. Firstly, we study the energy measurement and the energy spectrum of a fractal signal in the singularity domain, propose the conception of FEM and SES of multifractal signals, and investigate the Hausdorff measure and the local direction angle of the fractal energy element. Then, we prove the compatibility between FEM and traditional energy, and point out that SES can be measured in the fractal space. Finally, we study the algorithm of SES under the condition of a continuous signal and a discrete signal, and give the approximation algorithm of the latter, and the estimations of FEM and SES of the Gaussian white noise, Fractal Brownian motion and the multifractal Brownian motion show the theoretical significance and application value of FEM and SES.

  10. Three-dimensional acousto-optic spectrum analysis

    NASA Technical Reports Server (NTRS)

    Ansari, Homayoon; Metscher, Brian; Lesh, James R.

    1990-01-01

    A three-dimensional acoustooptic spectrum analyzer with subhertz resolution is demonstrated experimentally. The first and second dimensions are the two spatial dimensions of the output detector array, and the third dimension is time as sampled by the detector array frame rate. A superfine resolution of 0.12 Hz has been achieved.

  11. Dream Content Analysis in Persons with an Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Daoust, Anne-Marie; Lusignan, Felix-Antoine; Braun, Claude M. J.; Mottron, Laurent; Godbout, Roger

    2008-01-01

    Dream questionnaires were completed by 28 young adults with autism spectrum disorder (ASD) participants. Seventy-nine typically developed individual served as the control group. In a subset of 17 persons with ASD and 11 controls matched for verbal IQ, dream narratives were obtained following REM sleep awakenings in a sleep laboratory.…

  12. Image analysis and classification by spectrum enhancement: new developments

    NASA Astrophysics Data System (ADS)

    Crosta, Giovanni F.

    2010-01-01

    The "enhanced spectrum" of an image g[.] is a function h[.] of wave-number u obtained by a sequence of operations on the power spectral density of g[.]. The main properties and the available theorems on the correspondence between spectrum enhancement and spatial differentiation, of either integer or fractional order, are stated. In order to apply the enhanced spectrum to image classification, one has to go, by interpolation, from h[.] to a polynomial q[.]. The graph of q[.] provides the set of morphological descriptors of the original image, suitable for submission to a multivariate statistical classifier. Since q[.] depends on an n-tuple, Ψ, of parameters which control image pre-processing, spectrum enhancement and interpolation, then one can train the classifier by tuning Ψ. In fact, classifier training is more articulated and relies on a "design", whereby different training sets are processed. The best performing n-tuple, Ψ*, is selected by maximizing a "design-wide" figure of merit. Next one can apply the trained classifier to recognize new images. A recent application to materials science is summarized.

  13. Analysis of the gamma spectra of the uranium, actinium, and thorium decay series

    SciTech Connect

    Momeni, M.H.

    1981-09-01

    This report describes the identification of radionuclides in the uranium, actinium, and thorium series by analysis of gamma spectra in the energy range of 40 to 1400 keV. Energies and absolute efficiencies for each gamma line were measured by means of a high-resolution germanium detector and compared with those in the literature. A gamma spectroscopy method, which utilizes an on-line computer for deconvolution of spectra, search and identification of each line, and estimation of activity for each radionuclide, was used to analyze soil and uranium tailings, and ore.

  14. A new method of differential structural analysis of gamma-family basic parameters

    NASA Technical Reports Server (NTRS)

    Melkumian, L. G.; Ter-Antonian, S. V.; Smorodin, Y. A.

    1985-01-01

    The maximum likelihood method is used for the first time to restore parameters of electron photon cascades registered on X-ray films. The method permits one to carry out a structural analysis of the gamma quanta family darkening spots independent of the gamma quanta overlapping degree, and to obtain maximum admissible accuracies in estimating the energies of the gamma quanta composing a family. The parameter estimation accuracy weakly depends on the value of the parameters themselves and exceeds by an order of the values obtained by integral methods.

  15. 78 FR 31568 - Proposed Collection; 60-day Comment Request: Autism Spectrum Disorder Research Portfolio Analysis

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-24

    ... Spectrum Disorder Research Portfolio Analysis SUMMARY: In compliance with the requirement of Section 3506(c... Research Coordination, NIMH, NIH, Neuroscience Center, 6001 Executive Blvd., MSC 9663, Room 6184, Bethesda... days of the date of this publication. Proposed Collection: Autism Spectrum Disorder (ASD)...

  16. Analysis of a discrete spectrum analyzer for the detection of radio frequency interference

    NASA Technical Reports Server (NTRS)

    Levitt, B. K.

    1977-01-01

    As the radio frequency spectrum becomes increasingly overcrowded, interference with mission-critical DSN operations is rising at an alarming rate. To alleviate this problem the DSN is developing a wideband surveillance system for on-site detection and identification of potential sources of radio frequency interference (RFI), which will complement the existing frequency coordination activities. The RFI monitoring system is based on a wideband, multi-look discrete spectrum analyzer operating on fast Fourier transform principles. An extensive general statistical analysis is presented of such spectrum analyzers and derives threshold detection performance formulas for signals of interest. These results are then applied to the design of the RFI spectrum analyzer under development.

  17. Report on Ultra-high Resolution Gamma- / X-ray Analysis of Uranium Skull Oxide

    SciTech Connect

    Friedrich, S; Velazquez, M; Drury, O; Salaymeh, S

    2009-11-02

    We have utilized the high energy resolution and high peak-to-background ratio of superconducting TES {gamma}-detectors at very low energies for non-destructive analysis of a skull oxide derived from reprocessed nuclear fuel. Specifically, we demonstrate that superconducting detectors can separate and analyze the strong actinide emission lines in the spectral region below 60 keV that are often obscured in {gamma}-measurements with conventional Ge detectors.

  18. A low, adaptive dose of gamma-rays reduced the number and altered the spectrum of S1- mutants in human-hamster hybrid AL cells

    NASA Technical Reports Server (NTRS)

    Ueno, A. M.; Vannais, D. B.; Gustafson, D. L.; Wong, J. C.; Waldren, C. A.

    1996-01-01

    We examined the effects of a low, adaptive dose of 137Cs-gamma-irradiation (0.04 Gy) on the number and kinds of mutants induced in AL human-hamster hybrid cells by a later challenge dose of 4 Gy. The yield of S1- mutants was significantly less (by 53%) after exposure to both the adaptive and challenge doses compared to the challenge dose alone. The yield of hprt- mutants was similarly decreased. Incubation with cycloheximide (CX) or 3-aminobenzamide largely negated the decrease in mutant yield. The adaptive dose did not perturb the cell cycle, was not cytotoxic, and did not of itself increase the mutant yield above background. The adaptive dose did, however, alter the spectrum of S1- mutants from populations exposed only to the adaptive dose, as well as affecting the spectrum of S1- mutants generated by the challenge dose. The major change in both cases was a significant increase in the proportion of complex mutations compared to small mutations and simple deletions.

  19. Phenomenology of prompt gamma neutron activation analysis in the detection of mines and near-surface ordnance

    NASA Astrophysics Data System (ADS)

    Sparrow, David A.; Porter, Lisa J.; Broach, J. Thomas; Mehta-Sherbondy, Roshni J.

    1998-09-01

    Prompt gamma neutron activation analysis (PGNAA) has been proposed for confirming the presence of energetic materials as part of a mine or unexploded ordnance detection system. Ancore Corporation (previously SAIC Advanced Nucleonics Division), funded through Night Vision Electro Sciences Directorate by Environmental Security Test Certification Program, has carried out proof-of-concept demonstrations of PGNAA in this confirmatory role at Socorro, NM, and Yuma, AZ. In this, the first part of a two-part paper addressing the use of PGNAA in the detection of surface and near-surface UXO, we explore the phenomenology of PGNAA signals from surface or near-surface ordnance in soil to gain insight into the results of those demonstrations. PGNAA uses the high-energy gamma ray (10.8 MeV) from capture on N14 as a signature of the presence of nitrogen. This is one of the highest energy gamma rays resulting from neutron capture, and nitrogen is a major constituent of explosives, but a small portion of soil. Thus, PGNAA might be effective at confirming the presence of explosives. The phenomenology of dry soil is dominated by the two most common elements, oxygen and silicon. Neutrons injected into the soil elastically scatter from nuclei (predominantly oxygen), losing energy and propagating in a random walk fashion. Once slowed, neutron capture on soil elements produces a broad gamma-ray spectrum. Capture on Si29 produces a 10.6 MeV gamma, which is not resolvable from the nitrogen signal of interest using scintillation detectors. Thus, PGNAA will need either good resolution detectors, or robust background subtraction to estimate the silicon contribution. For any system unable to resolve the Si29 (10.6 MeV) and N14(10.8 MeV) gammas there is an inherently low signal to background, resulting primarily from the silicon in the soil. After background subtraction, there remains a challenging signal to noise level, where the noise is partly due to counting statistics and partly due to the

  20. Analysis of the Swift Gamma-Ray Bursts duration

    SciTech Connect

    Horvath, I.; Veres, P.; Balazs, L. G.; Kelemen, J.; Bagoly, Z.

    2008-10-22

    Two classes of gamma-ray bursts have been identified in the BATSE catalogs characterized by durations shorter and longer than about 2 seconds. There are, however, some indications for the existence of a third type of burst. Swift satellite detectors have different spectral sensitivity than pre-Swift ones for gamma-ray bursts. Therefore it is worth to reanalyze the durations and their distribution and also the classification of GRBs. Using The First BAT Catalog the maximum likelihood estimation was used to analyzed the duration distribution of GRBs. The three log-normal fit is significantly (99.54% probability) better than the two for the duration distribution. Monte-Carlo simulations also confirm this probability (99.2%)

  1. Gamma Detector Response and Analysis Software - Detector Response Function

    SciTech Connect

    2014-05-13

    GADRAS-DRF uses a Detector Response Function (DRF) to compute the response of gamma-ray detectors incident radiation. The application includes provision for plotting measured and computed spectra and for characterizing detector response parameters based on measurements of a series of calibration sources (e.g., Ba-133, Cs-137, Co-60, and Th-228). An application program interface enables other programs to access the dynamic-link library that is used to compute spectra.

  2. Extended analysis of fifth spectrum of bromine: Br V

    NASA Astrophysics Data System (ADS)

    Riyaz, A.; Tauheed, A.; Rahimullah, K.

    2014-11-01

    The fifth spectrum of bromine (Br V) has been studied in the 200-2400 Å wavelength region. The spectrum was photographed on a 3-m normal incidence vacuum spectrograph at the St. Francis Xavier University, Antigonish (Canada) and 6.65-m grazing incidence spectrograph at the Zeeman laboratory (Amsterdam). The light sources used were a triggered spark and sliding spark. The ground configuration of Br V is 4s24p. The excited configurations 4s4p2+4s2(4d+5d+5s+6s+7s+5g+6g)+4s4p(5p+4f)+4p24d in the even parity system and the 4p3+4s2(5p+6p+7p+4f)+4s4p4d+4s4p5s configurations in the odd parity system have been studied. Relativistic Hartree-Fock (HFR) and least squares fitted (LSF) parametric calculations have been used to interpret the observed spectrum. 99 levels of Br V have now been established, 43 being new. Among 394 classified spectral lines, 181 are newly classified. The level 4s27s 2S1/2 is revised. We estimate the accuracy of our measured wavelengths for sharp and unblended lines to be±0.005 Å. The ionization limit is determined as 479,657±200 cm-1 (59.470±0.025 eV).

  3. Autism spectrum traits in normal individuals: a preliminary VBM analysis

    PubMed Central

    Focquaert, Farah; Vanneste, Sven

    2015-01-01

    In light of the new DSM-5 autism spectrum disorders diagnosis in which the autism spectrum reflects a group of neurodevelopmental disorders existing on a continuum from mild to severe expression of autistic traits, and recent empirical findings showing a continuous distribution of autistic traits in the general population, our voxel based morphometry study compares normal individuals with high autistic traits to normal individuals with low autistic traits. We hypothesize that normal individuals with high autistic traits in terms of empathizing and systemizing [high systemizing (HS)/low empathizing (LE)] share brain irregularities with individuals that fall within the clinical autism spectrum disorder. We find differences in several social brain network areas between our groups. Specifically, we find increased gray matter (GM) volume in the orbitofrontal cortex, the cuneus, the hippocampus and parahippocampus and reduced GM volume in the inferior temporal cortex, the insula, and the amygdala in our HS/LE individuals relative to our HE/LS (low autistic traits in terms of empathizing and systemizing) individuals. PMID:26029082

  4. Prompt gamma ray evaluation for chlorine analysis in blended cement concrete.

    PubMed

    Naqvi, A A; Maslehuddin, M; Kalakada, Zameer; Al-Amoudi, O S B

    2014-12-01

    Single prompt gamma ray energy has been evaluated to measure chlorine concentration in fly ash (FA), Super-Pozz (SPZ) and blast furnace slag (BFS) cement concrete specimens using a portable neutron generator-based Prompt Gamma Neutron Activation (PGNAA) setup. The gamma ray yield data from chloride concentration measurement in FA, SPZ and BFS cement concretes for 2.86-3.10, 5.72 and 6.11MeV chlorine gamma rays were analyzed to identify a gamma ray with common slope (gamma ray yield/Cl conc. wt%) for the FA, BFS and SPZ cement concretes. The gamma ray yield data for FA and SPZ cement concretes with varying chloride concentration were measured previously using a portable neutron generator-based PGNAA setup. In the current study, new data have been measured for chlorine detection in the BFS cement concrete using a portable neutron generator-based PGNAA setup for 2.86-3.10, 5.72, and 6.11MeV chlorine gamma rays. The minimum detection limit of chlorine in BFS cement concrete (MDC) was found to be 0.034±0.010, 0.032±0.010, 0.033±0.010 for 2.86-3.10, 5.72 and 6.11MeV gamma ray, respectively. The new BFS cement concrete data, along with the previous measurements for FA and SPZ cement concretes, have been utilized to identify a gamma ray with a common slope to analyze the Cl concentration in all of these blended cement concretes. It has been observed that the 6.11MeV chlorine gamma ray has a common slope of 5295±265 gamma rays/wt % Cl concentration for the portable neutron generator-based PGNAA setup. The minimum detectable concentration (MDC) of chlorine in blended cement concrete was measured to be 0.033±0.010wt % for the portable neutron generator-based PGNAA. Thus, the 6.11MeV chlorine gamma ray can be used for chlorine analysis of blended cement concretes.

  5. Analysis of Data from the Balloon Borne Gamma RAy Polarimeter Experiment (GRAPE)

    NASA Astrophysics Data System (ADS)

    Wasti, Sambid K.; Bloser, Peter F.; Legere, Jason S.; McConnell, Mark L.; Ryan, James M.

    2016-04-01

    The Gamma Ray Polarimeter Experiment (GRAPE), a balloon borne polarimeter for 50~300 keV gamma rays, successfully flew in 2011 and 2014. The main goal of these balloon flights was to measure the gamma ray polarization of the Crab Nebula. Analysis of data from the first two balloon flights of GRAPE has been challenging due to significant changes in the background level during each flight. We have developed a technique based on the Principle Component Analysis (PCA) to estimate the background for the Crab observation. We found that the background depended mostly on the atmospheric depth, pointing zenith angle and instrument temperatures. Incorporating Anti-coincidence shield data (which served as a surrogate for the background) was also found to improve the analysis. Here, we present the calibration data and describe the analysis done on the GRAPE 2014 flight data.

  6. Analysis of gamma prime shape changes in a single crystal Ni-base superalloy

    NASA Technical Reports Server (NTRS)

    Gayda, J.; Mackay, R. A.

    1989-01-01

    The microstructural evolution of a commercial single crystal superalloy, NASAIR 100, is analyzed using the existing high-temperature lattice mismatch data and high-temperature moduli obtained from tests on single crystals of gamma and gamma prime. A multiparticle analysis of the microstructural evolution is performed using a novel microstructural lattice simulation technique, MCFET. Under a uniaxial stress, a regular array of gamma prime particles in the simulated microstructure is predicted to coalesce and form a plate morphology, with the broad faces of the plates and stress axis perpendicular in tension but parallel in compression. These results are consistent with changes in gamma prime shape observed in NASAIR 100 following creep testing at 1000 C.

  7. Utilization of recycled neutron source to teach prompt gamma analysis activation-PGNA

    NASA Astrophysics Data System (ADS)

    Delgado-Correal, Camilo; Munera, Hector

    2008-03-01

    Neutron activation analysis based on prompt gamma ray emission has significantly developed during the past twenty years. The technique is particularly suited for the identification of low atomic number elements, as nitrogen that is a main component of drugs and explosives. Identification of these substances is important in the context of humanitarian demining, and in the control of illicit traffic of drugs and explosives. As a good example of recycling of radioactive sources, a ^241Am-Be neutron source emitting 10^7neutron/s, that was not longer in use for other purposes at Ingeominas, was used to build a neutron irradiator that can be used to teach prompt gamma ray analysis, and other nuclear techniques. We irradiated individual samples, each about 4 gram, of three different elements: nitrogen in urea, silicon in milled rock, and cadmium in cadmium oxide. The prompt gamma rays emitted in the nuclear reactions ^112Cd (neutron,gamma) ^113Cd, ^28Si (neutron,gamma) ^29Si and ^14N (neutron,gamma) ^15N were identified using a well-type NaI (Tl) detector, connected to a multi-channel analyzer.

  8. Nuclear quadrupole resonance studies project. [spectrometer design and spectrum analysis

    NASA Technical Reports Server (NTRS)

    Murty, A. N.

    1978-01-01

    The participation of undergraduates in nuclear quadrupole resonance research at Grambling University was made possible by NASA grants. Expanded laboratory capabilities include (1) facilities for high and low temperature generation and measurement; (2) facilities for radio frequency generation and measurement with the modern spectrum analyzers, precision frequency counters and standard signal generators; (3) vacuum and glass blowing facilities; and (4) miscellaneous electronic and machine shop facilities. Experiments carried out over a five year period are described and their results analyzed. Theoretical studies on solid state crystalline electrostatic fields, field gradients, and antishielding factors are included.

  9. The analysis of a coherent frequency hopped spread spectrum system

    NASA Astrophysics Data System (ADS)

    Su, Chun-Meng; Milstein, Laurence B.

    A digital joint phase/timing tracking loop for a coherent frequency-hopped spread-spectrum system is analyzed for both training mode and tracking performance. Under minor assumptions, the phase error is modeled as a homogeneous finite Markov chain. The length of the training period, the approximate probability of entering the tracking range, the steady-state average error probability, and the mean-time to loss-of-lock are derived. The effects of both nonzero RF phase error and cubic channel phase response are presented. It is shown that the performance of the system can be designed to be close to that of a perfectly synchronized system.

  10. Development and analysis for core power gamma thermometer adaptation

    SciTech Connect

    Ren-Tai Chiang; Leong, T.

    1996-12-31

    The gamma thermometer (GT) has gained increasing interest to replace the local power range monitor (LPRM) and the traversing in-core probe (TIP) as the core monitoring device in new boiling water reactor (BWR) designs. The number of GTs is designed between the number of LPRMs, 4, and the number of TIPs, 24, per string, but its optimal number is yet to be determined. The authors have modified the BWR core Simulator PANACEA for analyzing the core power GT adaptation and have compared the axial core-averaged relative power distributions and two thermal limits of the GT 8- and 12-point adaptations against those of the TIP 24-point adaptation.

  11. Multi-shot analysis of the gamma reaction history diagnostica)

    NASA Astrophysics Data System (ADS)

    Sayre, D. B.; Bernstein, L. A.; Church, J. A.; Herrmann, H. W.; Stoeffl, W.

    2012-10-01

    The gamma reaction history diagnostic at the National Ignition Facility has the capability to determine a number of important performance metrics for cryogenic deuterium-tritium implosions: the fusion burn width, bang time and yield, as well as the areal density of the compressed ablator. Extracting those values from the measured γ rays of an implosion, requires accounting for a γ-ray background in addition to the impulse response function of the instrument. To address these complications, we have constructed a model of the γ-ray signal, and are developing a simultaneous multi-shot fitting routine to constrain its parameter space.

  12. M-BAND Analysis of Chromosome Aberration In Human Epithelial Cells exposed to Gamma-ray and Secondary Neutrons of Low Dose Rate

    NASA Technical Reports Server (NTRS)

    Hada, M.; Saganti, P. B.; Gersey, B.; Wilkins, R.; Cucinotta, F. A.; Wu, H.

    2007-01-01

    High-energy secondary neutrons, produced by the interaction of galactic cosmic rays with the atmosphere, spacecraft structure and planetary surfaces, contribute to a significant fraction to the dose equivalent in crew members and passengers during commercial aviation travel, and astronauts in space missions. The Los Alamos Nuclear Science Center (LANSCE) neutron facility's "30L" beam line is known to generate neutrons that simulate the secondary neutron spectrum of the Earth's atmosphere at high altitude. The neutron spectrum is also similar to that measured onboard spacecraft like the MIR and the International Space Station (ISS). To evaluate the biological damage, we exposed human epithelial cells in vitro to the LANSCE neutron beams at an entrance dose rate of 2.5 cGy/hr or gamma-ray at 1.7cGy/hr, and assessed the induction of chromosome aberrations that were identified with mBAND. With this technique, individually painted chromosomal bands on one chromosome allowed the identification of inter-chromosomal aberrations (translocation to unpainted chromosomes) and intra-chromosomal aberrations (inversions and deletions within a single painted chromosome). Compared to our previous results for gamma-rays and 600 MeV/nucleon Fe ions of high dose rate, the neutron data showed a higher frequency of chromosome aberrations. However, detailed analysis of the inversion type revealed that all of the three radiation types in the study induced a low incidence of simple inversions. The low dose rate gamma-rays induced a lower frequency of chromosome aberrations than high dose rate gamma-rays, but the inversion spectrum was similar for the same cytotoxic effect. The distribution of damage sites on chromosome 3 for different radiation types will also be discussed.

  13. Future Prospects for Space-Based Gamma Ray Astronomy

    NASA Astrophysics Data System (ADS)

    McConnell, Mark

    2015-04-01

    The gamma-ray sky offers a unique view into broad range of astrophysical phenomena, from nearby solar flares, to galactic pulsars, to gamma-ray bursts at the furthest reaches of the Universe. The Fermi mission has dramatically demonstrated the broad range of topics that can be addressed by gamma-ray observations. The full range of gamma-ray energies is quite broad, covering the electromagnetic spectrum at energies above about 100 keV. The energy range below several hundred GeV is the domain of space-based gamma-ray observatories, a range that is not completely covered by the Fermi LAT instrument. The gamma ray community has recently embarked on an effort to define the next steps for space-based gamma ray astronomy. These discussions are being facilitated through the Gamma-ray Science Interest Group (GammaSIG), which exists to provide community input to NASA in regards to current and future needs of the gamma-ray astrophysics community. The GammaSIG, as a part of the Physics of the Cosmos Program Analysis Group, provides a forum open to all members of the gamma-ray community. The GammaSIG is currently working to bring the community together with a common vision that will be expressed in the form of a community roadmap. This talk will summarize some of the latest results from active gamma ray observatories, including both Fermi and INTEGRAL, and will summarize the status of the community roadmap effort.

  14. Correlation Analysis of Prompt Emission from Gamma Ray Bursts

    NASA Astrophysics Data System (ADS)

    Pothapragada, Sriharsha

    Prompt emission from gamma-ray bursts (GRBs) exhibits very rapid, complicated temporal and spectral evolution. This diverse variability in the light-curves reflects the complicated nature of the underlying physics, in which inter-penetrating relativistic shells in the outflow are believed to generate strong magnetic fields that vary over very small scales. We use the theory of jitter radiation to model the emission from such regions and the resulting overall prompt gamma ray emission from a series of relativistic collisionless shocks. We present simulated GRB light-curves developed as a series of "pulses" corresponding to instantaneously illuminated "thin-shell" regions emitting via the jitter radiation mechanism. The effects of various geometries, viewing angles, and bulk Lorentz factor profiles of the radiating outflow jets on the spectral features and evolution of these light-curves are explored. Our results demonstrate how an anisotropic jitter radiation pattern, in conjunction with relativistic shock kinematics, can produce certain features observed in the GRB prompt emission spectra, such as the occurrence of hard, synchrotron violating spectra, the "tracking" of observed flux with spectral parameters, and spectral softening below peak energy within individual episodes of the light curve. We highlight predictions in the light of recent advances in the observational sphere of GRBs.

  15. Analysis of Multi-band Photometry of Violently Variable Gamma-Ray Sources

    NASA Astrophysics Data System (ADS)

    Kadowaki, Jennifer; Malkan, M. A.

    2013-01-01

    We studied the relationship between rapid variations in the jet intensities and changes in accretion disk activity of blazar subtype, Flat Spectrum Radio Quasar (FSRQ). Fifteen known FSRQs were specifically chosen for their prominent big blue bumps with redshifts near z=1, in order for the rest-frame UV to be redshifted into the blue-band pass. Flux changes for these 15 FSRQs were monitored for 15 observational nights in BVRI-bands and 20 nights in JHK-bands over a 12 month period using NASA's Fermi Gamma-ray Space Telescope, Lick Observatory's Nickel Telescope, and Kitt Peak National Observatory's 2.1 m Telescope. With 6.3’ x 6.3’ field of view for Nickel’s Direct Imaging Camera and 20’ x 20’ for Flamingos IR Imaging Spectrometer, approximately a half dozen, bright and non-variable stars were available to compare the concurrent changes in each of the quasar’s brightness. This process of differential photometry yielded photometric measurements of quasar brightness with 1-2% level precision. Light curves were then created for these 15 monitored quasars in optical, infrared, and gamma-ray energy bands. Dominating the redder emission spectrum due to non-thermal, synchrotron radiation and compton scattering of gamma-rays off high energy electrons, jet activity was compared to bluer spectral regions having strong accretion disk component with rest frame of approximately 2000 Angstroms. Most of the targeted FSRQs varied significantly over the 12 month monitoring period, with varying levels of fluctuations for each observed wavelength. Some correlations between gamma-ray and optical wavelengths were also present, which will be further discussed in the poster.

  16. Primordial power spectrum: a complete analysis with the WMAP nine-year data

    SciTech Connect

    Hazra, Dhiraj Kumar; Shafieloo, Arman; Souradeep, Tarun E-mail: arman@apctp.org

    2013-07-01

    We have improved further the error sensitive Richardson-Lucy deconvolution algorithm making it applicable directly on the un-binned measured angular power spectrum of Cosmic Microwave Background observations to reconstruct the form of the primordial power spectrum. This improvement makes the application of the method significantly more straight forward by removing some intermediate stages of analysis allowing a reconstruction of the primordial spectrum with higher efficiency and precision and with lower computational expenses. Applying the modified algorithm we fit the WMAP 9 year data using the optimized reconstructed form of the primordial spectrum with more than 300 improvement in χ{sup 2}{sub eff} with respect to the best fit power-law. This is clearly beyond the reach of other alternative approaches and reflects the efficiency of the proposed method in the reconstruction process and allow us to look for any possible feature in the primordial spectrum projected in the CMB data. Though the proposed method allow us to look at various possibilities for the form of the primordial spectrum, all having good fit to the data, proper error-analysis is needed to test for consistency of theoretical models since, along with possible physical artefacts, most of the features in the reconstructed spectrum might be arising from fitting noises in the CMB data. Reconstructed error-band for the form of the primordial spectrum using many realizations of the data, all bootstrapped and based on WMAP 9 year data, shows proper consistency of power-law form of the primordial spectrum with the WMAP 9 data at all wave numbers. Including WMAP polarization data in to the analysis have not improved much our results due to its low quality but we expect Planck data will allow us to make a full analysis on CMB observations on both temperature and polarization separately and in combination.

  17. A detailed analysis of the MIG spectrum for the development of laser based seam tracking sensors

    NASA Astrophysics Data System (ADS)

    Agapiou, G.; Kasiouras, C.; Serafetinides, A. A.

    1999-08-01

    This paper presents a detailed series of measurements of the spectrum of the light emitted from a MIG welding arc. This work was done in the framework of a larger project concerning the development of a seam tracking sensor. Detailed measurements and analysis of the spectrum produced from welding arcs have been performed. The measurements extend from the ultraviolet region of the spectrum (150 nm) to the near infrared region (970 nm) and have revealed the presence of many strong emission lines in the spectrum. The results are of great importance for the design of any optical or vision system working close to a welding arc, because the wavelength of the optical system can be selected to be close to a value where the spectrum of the arc causes the minimum interference to the laser light.

  18. [Application of the racial algorithm in energy dispersive X-ray fluorescence overlapped spectrum analysis].

    PubMed

    Zeng, Guo-Qiang; Luo, Yao-Yao; Ge, Liang-Quan; Zhang, Qing-Xian; Gu, Yi; Cheng, Feng

    2014-02-01

    In the energy dispersive X-ray fluorescence spectrum analysis, scintillation detector such as NaI (Tl) detector usually has a low energy resolution at around 8%. The low energy resolution causes problems in spectral data analysis especially in the high background and low counts condition, it is very limited to strip the overlapped spectrum, and the more overlapping the peaks are, the more difficult to peel the peaks, and the qualitative and quantitative analysis can't be carried out because we can't recognize the peak address and peak area. Based on genetic algorithm and immune algorithm, we build a new racial algorithm which uses the Euclidean distance as the judgment of evolution, the maximum relative error as the iterative criterion to be put into overlapped spectrum analysis, then we use the Gaussian function to simulate different overlapping degrees of the spectrum, and the racial algorithm is used in overlapped peak separation and full spectrum simulation, the peak address deviation is in +/- 3 channels, the peak area deviation is no more than 5%, and it is proven that this method has a good effect in energy dispersive X-ray fluorescence overlapped spectrum analysis.

  19. Study of medical isotope production facility stack emissions and noble gas isotopic signature using automatic gamma-spectra analysis platform

    NASA Astrophysics Data System (ADS)

    Zhang, Weihua; Hoffmann, Emmy; Ungar, Kurt; Dolinar, George; Miley, Harry; Mekarski, Pawel; Schrom, Brian; Hoffman, Ian; Lawrie, Ryan; Loosz, Tom

    2013-04-01

    The nuclear industry emissions of the four CTBT (Comprehensive Nuclear-Test-Ban Treaty) relevant radioxenon isotopes are unavoidably detected by the IMS along with possible treaty violations. Another civil source of radioxenon emissions which contributes to the global background is radiopharmaceutical production companies. To better understand the source terms of these background emissions, a joint project between HC, ANSTO, PNNL and CRL was formed to install real-time detection systems to support 135Xe, 133Xe, 131mXe and 133mXe measurements at the ANSTO and CRL 99Mo production facility stacks as well as the CANDU (CANada Deuterium Uranium) primary coolant monitoring system at CRL. At each site, high resolution gamma spectra were collected every 15 minutes using a HPGe detector to continuously monitor a bypass feed from the stack or CANDU primary coolant system as it passed through a sampling cell. HC also conducted atmospheric monitoring for radioxenon at approximately 200 km distant from CRL. A program was written to transfer each spectrum into a text file format suitable for the automatic gamma-spectra analysis platform and then email the file to a server. Once the email was received by the server, it was automatically analysed with the gamma-spectrum software UniSampo/Shaman to perform radionuclide identification and activity calculation for a large number of gamma-spectra in a short period of time (less than 10 seconds per spectrum). The results of nuclide activity together with other spectrum parameters were saved into the Linssi database. This database contains a large amount of radionuclide information which is a valuable resource for the analysis of radionuclide distribution within the noble gas fission product emissions. The results could be useful to identify the specific mechanisms of the activity release. The isotopic signatures of the various radioxenon species can be determined as a function of release time. Comparison of 133mXe and 133Xe activity

  20. ART-XC: A Medium-energy X-ray Telescope System for the Spectrum-R-Gamma Mission

    NASA Technical Reports Server (NTRS)

    Arefiev, V.; Pavlinsky, M.; Lapshov, I.; Thachenko, A.; Sazonov, S.; Revnivtsev, M.; Semena, N.; Buntov,M.; Vikhlinin, A.; Gubarev, M.; ODell, S.; Ramsey, B.; Romaine, S.; Swartz. D/; Weisskopf, M.; Hasinger, G.; Predehl, P.; Grigorovich, S.; Litvin, D.; Meidinger, N.; Strueder, L. W.

    2008-01-01

    The ART-XC instrument is an X-ray grazing-incidence telescope system in an ABRIXAS-type optical configuration optimized for the survey observational mode of the Spectrum-RG astrophysical mission which is scheduled to be launched in 2011. ART-XC has two units, each equipped with four identical X-ray multi-shell mirror modules. The optical axes of the individual mirror modules are not parallel but are separated by several degrees to permit the four modules to share a single CCD focal plane detector, 1/4 of the area each. The 450-micron-thick pnCCD (similar to the adjacent eROSITA telescope detector) will allow detection of X-ray photons up to 15 keV. The field of view of the individual mirror module is about 18 x 18 arcminutes(exp 2) and the sensitivity of the ART-XC system for 4 years of survey will be better than 10(exp -12) erg s(exp -1) cm(exp -2) over the 4-12 keV energy band. This will allow the ART-XC instrument to discover several thousand new AGNs.

  1. Analysis of the Palierne model by relaxation time spectrum

    NASA Astrophysics Data System (ADS)

    Kwon, Mi Kyung; Cho, Kwang Soo

    2016-02-01

    Viscoelasticity of immiscible polymer blends is affected by relaxation of the interface. Several attempts have been made for linear viscoelasticity of immiscible polymer blends. The Palierne model (1990) and the Gramespacher-Meissner model (1992) are representative. The Gramespacher-Meissner model consists of two parts: ingredients and interface. Moreover, it provides us the formula of the peak of interface in weighted relaxation time spectrum, which enables us to analyze the characteristics relating to interface more obviously. However, the Gramespacher-Meissner model is a kind of empirical model. Contrary to the Gramespacher-Meissner model, the Palierne model was derived in a rigorous manner. In this study, we investigated the Palierne model through the picture of the Gramespacher-Meissner model. We calculated moduli of immiscible blend using two models and obtained the weighted relaxation time spectra of them. The fixed-point iteration of Cho and Park (2013) was used in order to determine the weighted relaxation spectra.

  2. Estimating 2-D vector velocities using multidimensional spectrum analysis.

    PubMed

    Oddershede, Niels; Løvstakken, Lasse; Torp, Hans; Jensen, Jørgen Arendt

    2008-08-01

    Wilson (1991) presented an ultrasonic wideband estimator for axial blood flow velocity estimation through the use of the 2-D Fourier transform. It was shown how a single velocity component was concentrated along a line in the 2-D Fourier space, where the slope was given by the axial velocity. Later, it was shown that this approach could also be used for finding the lateral velocity component by also including a lateral sampling. A single velocity component would then be concentrated along a plane in the 3-D Fourier space, tilted according to the 2 velocity components. This paper presents 2 new velocity estimators for finding both the axial and lateral velocity components. The estimators essentially search for the plane in the 3- D Fourier space, where the integrated power spectrum is largest. The first uses the 3-D Fourier transform to find the power spectrum, while the second uses a minimum variance approach. Based on this plane, the axial and lateral velocity components are estimated. Several phantom measurements, for flow-to-depth angles of 60, 75, and 90 degrees, were performed. Multiple parallel lines were beamformed simultaneously, and 2 different receive apodization schemes were tried. The 2 estimators were then applied to the data. The axial velocity component was estimated with an average standard deviation below 2.8% of the peak velocity, while the average standard deviation of the lateral velocity estimates was between 2.0% and 16.4%. The 2 estimators were also tested on in vivo data from a transverse scan of the common carotid artery, showing the potential of the vector velocity estimation method under in vivo conditions. PMID:18986918

  3. Portable microcomputer unit for the analysis of plutonium gamma-ray spectra

    SciTech Connect

    Ruhter, W.D.; Camp, D.C.

    1981-10-01

    A portable microcomputer has been developed for the IAEA to perform in-field analysis of plutonium gamma-ray spectra. The unit includes a 16-bit LSI-11/2 microprocessor, 32K words of memory, a 20-character display for user prompting, and a 20-character thermal printer for hardcopy output. Only the positions of the 148-keV Pu-241 and 208-keV U-237 peaks are required for spectral analysis. The unit was tested against gamma-ray spectra taken of NBS plutonium standards and IAEA spectra. Results obtained are presented.

  4. Temperature dependence of CsI(Tl) gamma-ray scintillation decay time constants and emission spectrum

    NASA Astrophysics Data System (ADS)

    Valentine, John; Moses, William W.; Derenzo, Stephen E.; Wehe, David K.; Knoll, Glenn F.

    1992-12-01

    The gamma-ray excited, temperature dependent scintillation characteristics of CsI(Tl) are reported over the temperature range of -100 to +50 degree(s)C. The modified Bollinger-Thomas and shaped square wave methods were used to measure the rise and decay times. The emission spectra were measured using a monochromator and corrected for monochromator and photocathode spectral efficiency. The shaped square wave method was also used to determine the scintillation yield as was a current mode method. The thermoluminescence emissions of CsI(Tl) were measured using the same current mode method. At room temperature, CsI(Tl) was found to have two primary decay components with decay time constants of (tau) (subscript 1) equals 679 +/- 10 ns (63.7%) and (tau) (subscript 2) equals 3.34 +/- 0.14 microsecond(s) (36.1%) and to have emission bands at about 400 and 560 nm. The (tau) (subscript 1) luminescent state was observed to be populated by an exponential process with a resulting rise time constant of 19.6 +/- 1.9 ns at room temperature. An ultra-fast decay component with a < 0.5 ns decay time was found to emit about 0.2% (about 100 photons/MeV) of the total scintillation light. At -100 degree(s)C (tau) (subscript 2) was too long to be resolved and (tau) (subscript 1) was determined to be 3.52 +/- 0.39 microsecond(s) , while the 400 nm emission band was not observed. At +50 degree(s)C the decay constants were found to be 628 ns (70%) and 2.63 microsecond(s) (30%) and both emission bands are present. Four different commercially available CsI(Tl) crystals were used. Minimal variations in the measured scintillation characteristics were observed among these four crystals. Thermoluminescence emissions were observed to have peak yields at -90, -65, -40, +20, and possibly -55 degree(s)C. The relative magnitudes and number of thermoluminescence peaks were found to vary from crystal to crystal.

  5. Isotopic composition analysis and age dating of uranium samples by high resolution gamma ray spectrometry

    NASA Astrophysics Data System (ADS)

    Apostol, A. I.; Pantelica, A.; Sima, O.; Fugaru, V.

    2016-09-01

    Non-destructive methods were applied to determine the isotopic composition and the time elapsed since last chemical purification of nine uranium samples. The applied methods are based on measuring gamma and X radiations of uranium samples by high resolution low energy gamma spectrometric system with planar high purity germanium detector and low background gamma spectrometric system with coaxial high purity germanium detector. The "Multigroup γ-ray Analysis Method for Uranium" (MGAU) code was used for the precise determination of samples' isotopic composition. The age of the samples was determined from the isotopic ratio 214Bi/234U. This ratio was calculated from the analyzed spectra of each uranium sample, using relative detection efficiency. Special attention is paid to the coincidence summing corrections that have to be taken into account when performing this type of analysis. In addition, an alternative approach for the age determination using full energy peak efficiencies obtained by Monte Carlo simulations with the GESPECOR code is described.

  6. Pulse-shape analysis for gamma background rejection in thermal neutron radiation using CVD diamond detectors

    NASA Astrophysics Data System (ADS)

    Kavrigin, P.; Finocchiaro, P.; Griesmayer, E.; Jericha, E.; Pappalardo, A.; Weiss, C.

    2015-09-01

    A novel technique for the rejection of gamma background from charged-particle spectra was demonstrated using a CVD diamond detector with a 6Li neutron converter installed at a thermal neutron beamline of the TRIGA research reactor at the Atominstitut (Vienna University of Technology). Spectra of the alpha particles and tritons of 6Li(n,T)4He thermal neutron capture reaction were separated from the gamma background by a new algorithm based on pulse-shape analysis. The thermal neutron capture in 6Li is already used for neutron flux monitoring, but the ability to remove gamma background allows using a CVD diamond detector for thermal neutron counting. The pulse-shape analysis can equally be applied to all cases where the charged products of an interaction are absorbed in the diamond and to other background particles that fully traverse the detector.

  7. A compact neutron beam generator system designed for prompt gamma nuclear activation analysis.

    PubMed

    Ghassoun, J; Mostacci, D

    2011-08-01

    In this work a compact system was designed for bulk sample analysis using the technique of PGNAA. The system consists of (252)Cf fission neutron source, a moderator/reflector/filter assembly, and a suitable enclosure to delimit the resulting neutron beam. The moderator/reflector/filter arrangement has been optimised to maximise the thermal neutron component useful for samples analysis with a suitably low level of beam contamination. The neutron beam delivered by this compact system is used to irradiate the sample and the prompt gamma rays produced by neutron reactions within the sample elements are detected by appropriate gamma rays detector. Neutron and gamma rays transport calculations have been performed using the Monte Carlo N-Particle transport code (MCNP5).

  8. SEM/EDX spectrum imaging and statistical analysis of a metal/ceramic braze

    SciTech Connect

    KOTULA,PAUL G.; KEENAN,MICHAEL R.; ANDERSON,IAN M.

    2000-01-25

    Energy dispersive x-ray (EDX) spectrum imaging has been performed in a scanning electron microscope (SEM) on a metal/ceramic braze to characterize the elemental distribution near the interface. Statistical methods were utilized to extract the relevant information (i.e., chemical phases and their distributions) from the spectrum image data set in a robust and unbiased way. The raw spectrum image was over 15 Mbytes (7500 spectra) while the statistical analysis resulted in five spectra and five images which describe the phases resolved above the noise level and their distribution in the microstructure.

  9. Photoacoustic spectrum analysis for microstructure characterization in biological tissue: analytical model.

    PubMed

    Xu, Guan; Fowlkes, J Brian; Tao, Chao; Liu, Xiaojun; Wang, Xueding

    2015-05-01

    Photoacoustic spectrum (PA) analysis (PASA) has been found to have the ability to identify the microstructures in phantoms and biological tissues. PASA adopts the procedures in ultrasound spectrum analysis, although the signal generation mechanisms related to ultrasound backscatter and PA wave generation differ. The purpose of this study was to theoretically validate PASA. The analytical solution to the power spectrum of PA signals generated by identical microspheres following discrete uniform random distribution in space was derived. The simulation and experiment validation of the analytical solution include: (i) the power spectrum profile of a single microsphere with a diameter of 300 μm, and (ii) the PASA parameters of the PA signals generated by randomly distributed microspheres 100, 200, 300, 400 and 500 μm in diameter, at concentrations of 30, 60, 120, 240, 480 per 1.5(3) cm(3) in the observation range 0.5-13 MHz.

  10. Spectrum analysis of photoacoustic signals for tissue classification

    NASA Astrophysics Data System (ADS)

    Chitnis, Parag V.; Mamou, Jonathan; Sampathkumar, Ashwin; Feleppa, Ernest J.

    2014-03-01

    Quantitative ultrasound (QUS) estimates derived from power spectra of pulse-echo signals are sensitive to mi- crostructure and potentially can differentiate among tissues. However, QUS estimates do not provide molecular specificity. We investigated the feasibility of obtaining quantitative photoacoustic (QPA) estimates for sensi- tivity to microstructure and chromophores for tissue classification. QPA methods were tested using gel-based phantoms containing uniformly dispersed, black polyethylene spheres (1E5 particles/ml) with nominal mean diameters of 23.5, 29.5, 42.0, and 58.0 μm. A pulsed, 532-nm laser excited the photoacoustic (PA) response. A single-element, 34-MHz transducer with a 12-mm focal length was raster scanned over the phantom to acquire 3D PA data. Normalized power spectra were generated from the PA signals within 2079, moving (50% overlap), 1-mm-cube regions-of-interest (ROIs) to provide three QPA estimates: spectral slope (SS), spectral intercept (SI), and effective absorber size (EAS). SS and SI were computed using a linear-regression approximation to the normalized spectrum in the -6-dB band. EAS was computed by fitting the normalized spectrum in the -20-dB band to the multi-sphere analytical solution. All estimates were correlated with the size of particles dispersed in the phantoms. SS decreased while SI increased with an increase in particle size. EAS was correlated with nominal particle diameter, but particles aggregation and the finite bandwidth of the PAI system resulted in outliers. SS, SI, and EAS for the 23.5-μm-phantom were -0.14+/--0.04 dB/MHz, 4.8+/-1.3 dB, and 25.4+/-6.3 μm, respectively; the corresponding values for the 58.0-μm phantom were -0.47+/--0.03 dB/MHz, 15.6+/-0.9 dB, and 82.7+/-0.9 μm.

  11. Recording and spectrum analysis of the planarian electroencephalogram.

    PubMed

    Aoki, R; Wake, H; Sasaki, H; Agata, K

    2009-03-17

    Many animals produce continuous brainwaves, known as the electroencephalogram (EEG), but it is not known at what point in evolution the EEG developed. Planarians possess the most primitive form of brain, but still exhibit learning and memory behaviors. Here, we observed and characterized the EEG waveform of the planarian. We inserted a monopole electrode into the head of a planarian on a cold stage, and were able to observe the EEG at sub-microvolt amplitudes. The EEG had a continuous waveform, similar to that of evolutionarily advanced animals with more developed brains. Occasional myogenic potential spikes were observed in the EEG due to sticking of the electrode, but this was markedly diminished by cooling the sample, which enabled us to investigate the intrinsic character of the continuous EEG waveform. The frequency spectrum of the EEG was observed in the range of 0.1-5 Hz, showing a broad rise below 0.5 Hz and a monotonic decrease above 1 Hz, apparently following the 1/f law. The intensity of the total EEG diminished during anesthesia by cooling to 2-3 degrees C, and recovered when the sample was warmed to about 10 degrees C. The EEG signal was sustained for 30-40 min, and gradually weakened as the animal died. Stimulation of the planarian with water vibration at 0.5-2 Hz induced chaotic resonance with a broad peak spectrum of around the stimulation frequency. Strong illumination suppressed the EEG signals for several minutes, with the degree of suppression positively correlating with the intensity of the light. This provides evidence that the EEG responds to optical signals, although there were no synchronous reactions to light flashes. The continuous EEG waveform suggests the existence of feedback loop circuits in the neural network of the planarian, which was supposed in electric shock memory experiments [McConnell JV, Cornwell P, Clay M (1960) An apparatus for conditioning planaria. Am J Psychol 73:618-622]. However, because of the broad band character of

  12. The Far-Infrared Polarization Spectrum: First Results and Analysis

    NASA Technical Reports Server (NTRS)

    Hildebrand, R. H.; Dotson, J. L.; Dowell, C. D.; Schleuning, D. A.; Vaillancourt, J. E.

    1999-01-01

    We present data on the polarization of the thermal emission from Galactic Clouds at 60 micrometers, 100 micrometers, and 350 micrometers. There are examples of rising polarization spectra in dense cloud cores [P(350 micrometers/P(100 micrometers) approximately equal to 2], and falling spectra in cloud envelopes [P(350)/P(100 micrometers) approximately equal to 0.6]. We also present data showing that the relationship, P(tau), between polarization and optical depth in cloud cores is different from that in cloud envelopes. We review the principles governing the far-infrared polarization spectrum and discuss applications to the data on P(lambda) and P(tau). We conclude that the cloud envelopes we have observed must contain two populations of grains that differ in their polarization efficiencies and in their emission spectra. We propose a model for cloud envelopes in which the contrasting populations reside in domains of different mean temperatures where the warmer domains contain the aligned grains.

  13. Determination of hydrogen in titanium alloys by cold neutron prompt gamma activation analysis

    SciTech Connect

    Paul, R.L.; Lindstrom, R.M.; Greenberg, R.R.; Privett, H.M. III; Richards, W.J.

    1996-11-01

    Cold neutron prompt gamma-ray activation analysis (CNPGAA) has proven useful for the analysis of hydrogen in titanium alloys. The analysis is nondestructive, measures the entire sample, and the results are independent of the chemical form of hydrogen present. The authors have used the technique to measure H mass fractions as low as 50 mg/kg in titanium-alloy jet-engine compressor blades and to measure hydrogen in standards for neutron tomography.

  14. Field evaporation behaviour in the gamma phase in Ti-Al during analysis in the tomographic atom probe.

    PubMed

    Lefebvre, W; Loiseau, A; Menand, A

    2002-07-01

    A Ti-48 at% Al alloy has been successfully investigated, using atom probe field ion microscopy and transmission electron microscopy. After a specific heat treatment, this alloy has a (alpha2 + gamma) lamellar microstructure. Using the tomographic atom probe (TAP), it has been possible to image the stacking of superlattice planes of gamma and to identify titanium as the highest evaporation field element. In addition, the influence of analysis site on atom probe measurements has been estimated for this phase. A TAP analysis has also made it possible to observe an extremely thin step along a gamma/gamma interface at a near atomic scale.

  15. Spectral analysis of the fifth spectrum of indium: In V

    NASA Astrophysics Data System (ADS)

    Swapnil; Tauheed, A.

    2016-01-01

    The fifth spectrum of indium (In V) has been investigated in the grazing and normal incidence wavelength regions. In4+ is a Rh-like ion with the ground configuration 4p64d9 and first excited configurations of the type 4p64d8nℓ (n≥4). The theoretical predications for this ion were made by Cowan's quasi-relativistic Hartree-Fock code with superposition of configurations involving 4p64d8(5p+6p+7p+4f+5f+6f), 4p54d10, 4p64d75s(5p+4f) for the odd parity matrix and 4p64d8 (5s+6s+7s+5d+6d), 4p64d7(5s2+5p2) for the even parity system. The spectra used for this work were recorded on 10.7 m grazing and normal incidence spectrographs at the National Institute of Standards and Technology, Gaithersburg, Maryland (USA) and also on a 3-m normal incidence vacuum spectrograph at Antigonish (Canada). The sources used were a sliding spark and a triggered spark respectively. Two hundred and thirty two energy levels based on the identification of 873 spectral lines have been established, forty six being new. Least squares fitted parametric calculations were used to interpret the observed level structure. The energy levels were optimized using a level optimization computer program (LOPT). Our wavelength accuracy for sharp and unblended lines is estimated to be within ±0.005 Å for λ below 400 Å and ±0.006 Å up to 1200 Å.

  16. EEG Power Spectrum Analysis in Children with ADHD

    PubMed Central

    Kamida, Akira; Shimabayashi, Kenta; Oguri, Masayoshi; Takamori, Toshihiro; Ueda, Naoyuki; Koyanagi, Yuki; Sannomiya, Naoko; Nagira, Haruki; Ikunishi, Saeko; Hattori, Yuiko; Sato, Kengo; Fukuda, Chisako; Hirooka, Yasuaki; Maegaki, Yoshihiro

    2016-01-01

    Background Attention deficit disorder/hyperactivity disorder (ADHD) is a pathological condition that is not fully understood. In this study, we investigated electroencephalographic (EEG) power differences between children with ADHD and healthy control children. Methods EEGs were recorded as part of routine medical care received by 80 children with ADHD aged 4–15 years at the Department of Pediatric Neurology in Tottori University Hospital. Additionally, we recorded in 59 control children aged 4–15 years after obtaining informed consent. Specifically, awake EEG signals were recorded from each child using the international 10–20 system, and we used ten 3-s epochs on the EEG power spectrum to calculate the powers of individual EEG frequency bands. Results The powers of different EEG bands were significantly higher in the frontal brain region of those in the ADHD group compared with the control group. In addition, the power of the beta band in the ADHD group was significantly higher in all brain regions, except for the occipital region, compared with control children. With regard to developmental changes, the power of the alpha band in the occipital region showed an age-dependent decrease in both groups, with slightly lower power in the ADHD group. Additionally, the intergroup difference decreased in children aged 11 years or older. As with the alpha band in the occipital region, the beta band in the frontal region showed an age-dependent decrease in both groups. Unlike the alpha band, the power of the beta band was higher in the ADHD group than in the control group for children of all ages. Conclusion The observed intergroup differences in EEG power may provide insight into the brain function of children with ADHD. PMID:27493489

  17. Dosimetric comparison of tools for intensity modulated radiation therapy with gamma analysis: a phantom study

    NASA Astrophysics Data System (ADS)

    Akbas, Ugur; Okutan, Murat; Demir, Bayram; Koksal, Canan

    2015-07-01

    Dosimetry of the Intensity Modulated Radiation Therapy (IMRT) is very important because of the complex dose distributions. Diode arrays are the most common and practical measurement tools for clinical usage for IMRT. Phantom selection is critical for QA process. IMRT treatment plans are recalculated for the phantom irradiation in QA. Phantoms are made in different geometrical shapes to measure the doses of different types of irradiation techniques. Comparison of measured and calculated dose distributions for IMRT can be made by using gamma analysis. In this study, 10 head-and-neck IMRT QA plans were created with Varian Eclipse 8.9 treatment planning system. Water equivalent RW3-slab phantoms, Octavius-2 phantom and PTW Seven29 2D-array were used for QA measurements. Gantry, collimator and couch positions set to 00 and QA plans were delivered to RW3 and Octavius phantoms. Then the positions set to original angles and QA plans irradiated again. Measured and calculated fluence maps were evaluated with gamma analysis for different DD and DTA criteria. The effect of different set-up conditions for RW3 and Octavius phantoms in QA plan delivery evaluated by gamma analysis. Results of gamma analysis show that using RW3-slab phantoms with setting parameters to 00 is more appropriate for IMRT QA.

  18. Upgrade of the NIST Thermal Neutron Prompt-Gamma-Ray Activation Analysis Facility

    SciTech Connect

    E. A. Mackey; D. L. Anderson; G. Lamaze; R. M. Lindstrom; P. J. Liposky

    2000-11-12

    The thermal neutron prompt-gamma-ray activation analysis facility at the National Institute of Standards and Technology (NIST) was designed and built in the late 1970s. An upgrade of the facility to reduce background and enhance analytical sensitivities is in progress, and is described in this report.

  19. Gamma Detector Response and Analysis Software%u2013Detector Response Function

    2015-04-01

    Version 00 GADRAS-DRF contains a suite of capabilities related to radiation detection. Its primary function is the simulation of gamma-ray and neutron detector signals to radiation sources. It also contains limited analysis functionality. GADRAS-DRF is the public version of the full version of GADRAS with capabilities such as radiation transport and advanced analyses removed.

  20. Imaging of heterogeneous materials by prompt gamma-ray neutron activation analysis

    SciTech Connect

    Staples, P.; Prettyman, T.; Lestone, J.

    1998-12-01

    The authors have used a tomographic gamma scanner (TGS) to produce tomographic prompt gamma-ray neutron activation analysis imaging (PGNAA) of heterogeneous matrices. The TGS was modified by the addition of graphite reflectors that contain isotopic neutron sources for sample interrogation. The authors are in the process of developing the analysis methodology necessary for a quantitative assay of large containers of heterogeneous material. This nondestructive analysis (NDA) technique can be used for material characterization and the determination of neutron assay correction factors. The most difficult question to be answered is the determination of the source-to-sample coupling term. To assist in the determination of the coupling term, the authors have obtained images for a range of sample that are very well characterized, such as, homogenous pseudo one-dimensional samples to three-dimensional heterogeneous samples. They then compare the measurements to MCNP calculations. For an accurate quantitative measurement, it is also necessary to determine the sample gamma-ray self attenuation at higher gamma-ray energies, namely pair production should be incorporated into the analysis codes.

  1. Documentation of the data analysis system for the gamma ray monitor aboard OSO-H

    NASA Technical Reports Server (NTRS)

    Croteau, S.; Buck, A.; Higbie, P.; Kantauskis, J.; Foss, S.; Chupp, D.; Forrest, D. J.; Suri, A.; Gleske, I.

    1973-01-01

    The programming system is presented which was developed to prepare the data from the gamma ray monitor on OSO-7 for scientific analysis. The detector, data, and objectives are described in detail. Programs presented include; FEEDER, PASS-1, CAL1, CAL2, PASS-3, Van Allen Belt Predict Program, Computation Center Plot Routine, and Response Function Programs.

  2. GC-MS Analysis of [gamma]-Hydroxybutyric Acid Analogs: A Forensic Chemistry Experiment

    ERIC Educational Resources Information Center

    Henck, Colin; Nally, Luke

    2007-01-01

    An upper-division forensic chemistry experiment is described. It involves using glycolic acid and sodium glycolate as analogs of [gamma]-hydroxybutyric acid and its sodium salt. The experiment shows the use of silylation in GC-MS analysis and gives students the opportunity to work with a commonly used silylating reagent,…

  3. Continuous versus pulse neutron induced gamma spectroscopy for soil carbon analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Neutron induced gamma spectra analysis (NGA) provides a means of measuring carbon in large soil volumes without destructive sampling. Calibration of the NGA system must account for system background and the interference of other nuclei on the carbon peak at 4.43 MeV. Accounting for these factors pro...

  4. High resolution gamma-ray spectroscopy applied to bulk sample analysis

    SciTech Connect

    Kosanke, K.L.; Koch, C.D.; Wilson, R.D.

    1980-01-01

    A high resolution Ge(Li) gamma-ray spectrometer has been installed and made operational for use in routine bulk sample analysis by the Bendix Field Engineering Corporation (BFEC) geochemical analysis department. The Ge(Li) spectrometer provides bulk sample analyses for potassium, uranium, and thorium that are superior to those obtained by the BFEC sodium iodide spectrometer. The near term analysis scheme permits a direct assay for uranium that corrects for bulk sample self-absorption effects and is independent of the uranium/radium disequilibrium condition of the sample. A more complete analysis scheme has been developed that fully utilizes the gamma-ray data provided by the Ge(Li) spectrometer and that more properly accounts for the sample self-absorption effect. This new analysis scheme should be implemented on the BFEC Ge(Li) spectrometer at the earliest date.

  5. Factor Analysis of the Aberrant Behavior Checklist in Individuals with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Brinkley, Jason; Nations, Laura; Abramson, Ruth K.; Hall, Alicia; Wright, Harry H.; Gabriels, Robin; Gilbert, John R.; Pericak-Vance, Margaret A. O.; Cuccaro, Michael L.

    2007-01-01

    Exploratory factor analysis (varimax and promax rotations) of the aberrant behavior checklist-community version (ABC) in 275 individuals with Autism spectrum disorder (ASD) identified four- and five-factor solutions which accounted for greater than 70% of the variance. Confirmatory factor analysis (Lisrel 8.7) revealed indices of moderate fit for…

  6. Sociosexuality Education for Persons with Autism Spectrum Disorders Using Principles of Applied Behavior Analysis

    ERIC Educational Resources Information Center

    Wolfe, Pamela S.; Condo, Bethany; Hardaway, Emily

    2009-01-01

    Applied behavior analysis (ABA) has emerged as one of the most effective empirically based strategies for instructing individuals with autism spectrum disorders (ASD). Four ABA-based strategies that have been found effective are video modeling, visual strategies, social script fading, and task analysis. Individuals with ASD often struggle with…

  7. High Resolution Gamma Ray Analysis of Medical Isotopes

    NASA Astrophysics Data System (ADS)

    Chillery, Thomas

    2015-10-01

    Compton-suppressed high-purity Germanium detectors at the University of Massachusetts Lowell have been used to study medical radioisotopes produced at Brookhaven Linac Isotope Producer (BLIP), in particular isotopes such as Pt-191 used for cancer therapy in patients. The ability to precisely analyze the concentrations of such radio-isotopes is essential for both production facilities such as Brookhaven and consumer hospitals across the U.S. Without accurate knowledge of the quantities and strengths of these isotopes, it is possible for doctors to administer incorrect dosages to patients, thus leading to undesired results. Samples have been produced at Brookhaven and shipped to UML, and the advanced electronics and data acquisition capabilities at UML have been used to extract peak areas in the gamma decay spectra. Levels of Pt isotopes in diluted samples have been quantified, and reaction cross-sections deduced from the irradiation parameters. These provide both cross checks with published work, as well as a rigorous quantitative framework with high quality state-of-the-art detection apparatus in use in the experimental nuclear physics community.

  8. An Analysis Methodology for the Gamma-ray Large Area Space Telescope

    NASA Technical Reports Server (NTRS)

    Morris, Robin D.; Cohen-Tanugi, Johann

    2004-01-01

    The Large Area Telescope (LAT) instrument on the Gamma Ray Large Area Space Telescope (GLAST) has been designed to detect high-energy gamma rays and determine their direction of incidence and energy. We propose a reconstruction algorithm based on recent advances in statistical methodology. This method, alternative to the standard event analysis inherited from high energy collider physics experiments, incorporates more accurately the physical processes occurring in the detector, and makes full use of the statistical information available. It could thus provide a better estimate of the direction and energy of the primary photon.

  9. Enhanced Analysis Techniques for an Imaging Neutron and Gamma Ray Spectrometer

    NASA Astrophysics Data System (ADS)

    Madden, Amanda C.

    The presence of gamma rays and neutrons is a strong indicator of the presence of Special Nuclear Material (SNM). The imaging Neutron and gamma ray SPECTrometer (NSPECT) developed by the University of New Hampshire and Michigan Aerospace corporation detects the fast neutrons and prompt gamma rays from fissile material, and the gamma rays from radioactive material. The instrument operates as a double scatter device, requiring a neutron or a gamma ray to interact twice in the instrument. While this detection requirement decreases the efficiency of the instrument, it offers superior background rejection and the ability to measure the energy and momentum of the incident particle. These measurements create energy spectra and images of the emitting source for source identification and localization. The dual species instrument provides superior detection than a single species alone. In realistic detection scenarios, few particles are detected from a potential threat due to source shielding, detection at a distance, high background, and weak sources. This contributes to a small signal to noise ratio, and threat detection becomes difficult. To address these difficulties, several enhanced data analysis tools were developed. A Receiver Operating Characteristic Curve (ROC) helps set instrumental alarm thresholds as well as to identify the presence of a source. Analysis of a dual-species ROC curve provides superior detection capabilities. Bayesian analysis helps to detect and identify the presence of a source through model comparisons, and helps create a background corrected count spectra for enhanced spectroscopy. Development of an instrument response using simulations and numerical analyses will help perform spectra and image deconvolution. This thesis will outline the principles of operation of the NSPECT instrument using the double scatter technology, traditional analysis techniques, and enhanced analysis techniques as applied to data from the NSPECT instrument, and an

  10. Maternal Smoking and Autism Spectrum Disorder: A Meta-Analysis

    ERIC Educational Resources Information Center

    Rosen, Brittany N.; Lee, Brian K.; Lee, Nora L.; Yang, Yunwen; Burstyn, Igor

    2015-01-01

    We conducted a meta-analysis of 15 studies on maternal prenatal smoking and ASD risk in offspring. Using a random-effects model, we found no evidence of an association (summary OR 1.02, 95% CI 0.93-1.12). Stratifying by study design, birth year, type of healthcare system, and adjustment for socioeconomic status or psychiatric history did not alter…

  11. Spectrum-Based and Collaborative Network Topology Analysis and Visualization

    ERIC Educational Resources Information Center

    Hu, Xianlin

    2013-01-01

    Networks are of significant importance in many application domains, such as World Wide Web and social networks, which often embed rich topological information. Since network topology captures the organization of network nodes and links, studying network topology is very important to network analysis. In this dissertation, we study networks by…

  12. The gamma ray spectrometer for the Solar Maximum Mission

    NASA Technical Reports Server (NTRS)

    Forrest, D. J.; Chupp, E. L.; Ryan, J. M.; Cherry, M. L.; Gleske, I. U.; Reppin, C.; Pinkau, K.; Rieger, E.; Kanbach, G.; Kinzer, R. L.

    1980-01-01

    The paper describes an actively shielded, multicrystal scintillation spectrometer for measurement of the solar gamma ray flux used by the Solar Maximum Mission Gamma Ray Experiment. The instrument provides a 476-channel pulse height spectrum every 16.38 s over the 0.3-9 MeV energy range; the gamma ray spectral analysis can be extended to at least 15 MeV on command. The instrument is designed to measure the intensity, energy, and Doppler shift of narrow gamma ray lines, the intensity of extremely broadened lines, and the photon continuum.

  13. Effects of spatial resolution and noise on gamma analysis for IMRT QA

    PubMed Central

    Huang, Jessie Y.; Pulliam, Kiley B.; McKenzie, Elizabeth M.; Followill, David S.; Kry, Stephen F.

    2014-01-01

    We investigated the sensitivity of the gamma index to two factors: the spatial resolution and the noise level in the measured dose distribution. We also examined how the choice of reference distribution and analysis software affect the sensitivity of gamma analysis to these two factors for quality assurance (QA) of intensity-modulated radiation therapy (IMRT) treatment plans. For ten clinical IMRT plans, the dose delivered to a transverse dose plane was measured with EDR2 radiographic film. To evaluate the effects of spatial resolution, each irradiated film was digitized using three different resolutions (71, 142, and 285 dpi). To evaluate the effects of image noise, 1% and 2% local Gaussian noise was added to the film images. Gamma analysis was performed using 2%/2 mm and 3%/3 mm acceptance criteria and two commercial software packages, OmniPro I’mRT and DoseLab Pro. Dose comparisons were performed with the treatment planning system (TPS)-calculated dose as the reference, and then repeated with the film as the reference to evaluate how the choice of reference distribution affects the results of dose comparisons. When the TPS-calculated dose was designated as the reference distribution, the percentage of pixels with passing gamma values increased with both increasing resolution and noise. For 3%/3 mm acceptance criteria, increasing the film image resolution by a factor of two and by a factor of four caused a median increase of 0.9% and 2.6%, respectively, in the percentage of pixels passing. Increasing the noise level in the film image resulted in a median increase in percentage of pixels passing of 5.5% for 1% added local Gaussian noise and 5.8% for 2% added noise. In contrast, when the film was designated as the reference distribution, the percentage of pixels passing decreased with increased film noise, while increased resolution had no significant effect on passing rates. Furthermore, the sensitivity of gamma analysis to noise and resolution differed between

  14. Measurement of the moments of the photon energy spectrum in B{yields}X{sub s}{gamma} decays and determination of |V{sub cb}| and m{sub b} at Belle

    SciTech Connect

    Schwanda, C.; Mandl, F.; Mitaroff, W.; Urquijo, P.; Barberio, E.; Limosani, A.; Dalseno, J.; Moloney, G. R.; Sevior, M. E.; Taylor, G. N.; Wedd, R.; Adachi, I.; Haba, J.; Hazumi, M.; Itoh, R.; Iwasaki, Y.; Katayama, N.; Kichimi, H.; Krokovny, P.; Nakao, M.

    2008-08-01

    Using the previous Belle measurement of the inclusive photon energy in B{yields}X{sub s}{gamma} decays, we determine the first and second moments of this spectrum for minimum photon energies in the B meson rest frame ranging from 1.8 to 2.3 GeV. Combining these measurements with recent Belle data on the lepton energy and hadronic mass moments in B{yields}X{sub c}l{nu} decays, we perform fits to theoretical expressions derived in the 1S and kinetic mass schemes and extract the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element V{sub cb}, the b-quark mass, and other nonperturbative parameters. In the 1S scheme analysis we find |V{sub cb}|=(41.56{+-}0.68(fit){+-}0.08({tau}{sub B}))x10{sup -3} and m{sub b}{sup 1S}=(4.723{+-}0.055) GeV. In the kinetic scheme, we obtain |V{sub cb}|=(41.58{+-}0.69(fit){+-}0.08({tau}{sub B}){+-}0.58(th))x10{sup -3} and m{sub b}{sup kin}=(4.543{+-}0.075) GeV.

  15. Implementation of modal combination rules for response spectrum analysis using GEMINI

    SciTech Connect

    Nukala, P K

    1999-06-01

    One of the widely used methodologies for describing the behavior of a structural system subjected to seismic excitation is response spectrum modal dynamic analysis. Several modal combination rules are proposed in the literature to combine the responses of individual modes in a response spectrum dynamic analysis. In particular, these modal combination rules are used to estimate the representative maximum value of a particular response of interest for design purposes. Furthermore, these combination rules also provide guidelines for combining the representative maximum values of the response obtained for each of the three orthogonal spatial components of an earthquake. This report mainly focuses on the implementation of different modal combination rules into GEMINI [I].

  16. Reply to ``Comment on `Mobility spectrum computational analysis using a maximum entropy approach' ''

    NASA Astrophysics Data System (ADS)

    Mironov, O. A.; Myronov, M.; Kiatgamolchai, S.; Kantser, V. G.

    2004-03-01

    In their Comment [J. Antoszewski, D. D. Redfern, L. Faraone, J. R. Meyer, I. Vurgaftman, and J. Lindemuth, Phys. Rev. E 69, 038701 (2004)] on our paper [S. Kiatgamolchai, M. Myronov, O. A. Mironov, V. G. Kantser, E. H. C. Parker, and T. E. Whall, Phys. Rev. E 66, 036705 (2002)] the authors present computational results obtained with the improved quantitative mobility spectrum analysis technique implemented in the commercial software of Lake Shore Cryotronics. We suggest that this is just information additional to the mobility spectrum analysis (MSA) in general without any direct relation to our maximum entropy MSA (ME-MSA) algorithm.

  17. Cold neutron prompt gamma-ray activation analysis at NIST - an overview

    SciTech Connect

    Paul, R.L.; Lindstrom, R.M.

    1994-12-31

    An instrument for cold neutron capture prompt gamma-ray activation analysis (CNPGAA), located in the cold neutron research facility (CNRF) at the National Institute of Standards and Technology (NIST) has proven useful for the analysis of hydrogen and other elements in a wide variety of materials. The intent of this paper is to provide an overview of the instrument, focusing on recent improvements and the impact of these improvement on measurements.

  18. Quaternion Singular Spectrum Analysis of Electroencephalogram With Application in Sleep Analysis.

    PubMed

    Enshaeifar, Shirin; Kouchaki, Samaneh; Took, Clive Cheong; Sanei, Saeid

    2016-01-01

    A novel quaternion-valued singular spectrum analysis (SSA) is introduced for multichannel analysis of electroencephalogram (EEG). The analysis of EEG typically requires the decomposition of data channels into meaningful components despite the notoriously noisy nature of EEG--which is the aim of SSA. However, the singular value decomposition involved in SSA implies the strict orthogonality of the decomposed components, which may not reflect accurately the sources which exhibit similar neural activities. To allow for the modelling of such co-channel coupling, the quaternion domain is considered for the first time to formulate the SSA using the augmented statistics. As an application, we demonstrate how the augmented quaternion-valued SSA (AQSSA) can be used to extract the sources, even at a signal-to-noise ratio as low as -10 dB. To illustrate the usefulness of our quaternion-valued SSA in a rehabilitation setting, we employ the proposed SSA for sleep analysis to extract statistical descriptors for five-stage classification (Awake, N1, N2, N3 and REM). The level of agreement using these descriptors was 74% as quantified by the Cohen's kappa.

  19. Quaternion Singular Spectrum Analysis of Electroencephalogram With Application in Sleep Analysis.

    PubMed

    Enshaeifar, Shirin; Kouchaki, Samaneh; Took, Clive Cheong; Sanei, Saeid

    2016-01-01

    A novel quaternion-valued singular spectrum analysis (SSA) is introduced for multichannel analysis of electroencephalogram (EEG). The analysis of EEG typically requires the decomposition of data channels into meaningful components despite the notoriously noisy nature of EEG--which is the aim of SSA. However, the singular value decomposition involved in SSA implies the strict orthogonality of the decomposed components, which may not reflect accurately the sources which exhibit similar neural activities. To allow for the modelling of such co-channel coupling, the quaternion domain is considered for the first time to formulate the SSA using the augmented statistics. As an application, we demonstrate how the augmented quaternion-valued SSA (AQSSA) can be used to extract the sources, even at a signal-to-noise ratio as low as -10 dB. To illustrate the usefulness of our quaternion-valued SSA in a rehabilitation setting, we employ the proposed SSA for sleep analysis to extract statistical descriptors for five-stage classification (Awake, N1, N2, N3 and REM). The level of agreement using these descriptors was 74% as quantified by the Cohen's kappa. PMID:26276995

  20. Advanced alpha spectrum analysis based on the fitting and covariance analysis of dependent variables

    NASA Astrophysics Data System (ADS)

    Ihantola, S.; Pelikan, A.; Pöllänen, R.; Toivonen, H.

    2011-11-01

    The correct handling of statistical uncertainties is crucial especially when unfolding alpha spectra that contain a low number of counts or overlapping peaks from different nuclides. For this purpose, we have developed a new spectrum analysis software package called ADAM, which performs a full covariance calculus for alpha-particle emitting radionuclides. By analyzing a large number of simulated and measured spectra, the program was proved to give unbiased peak areas and statistically correct uncertainty limits. This applies regardless of the peak areas and the number of unknown parameters during the fitting. In addition, ADAM performs reliable deconvolution for multiplets, which opens the way for the determination of isotope ratios, such as 239Pu/240Pu.

  1. THE SPECTRUM OF ISOTROPIC DIFFUSE GAMMA-RAY EMISSION BETWEEN 100 MeV AND 820 GeV

    SciTech Connect

    Ackermann, M.; Buehler, R.; Ajello, M.; Albert, A.; Blandford, R. D.; Bloom, E. D.; Bottacini, E.; Caliandro, G. A.; Atwood, W. B.; Baldini, L.; Bellazzini, R.; Ballet, J.; Bastieri, D.; Buson, S.; Bechtol, K.; Bissaldi, E.; Brandt, T. J.; Bregeon, J. [Laboratoire Univers et Particules de Montpellier, Université Montpellier 2, CNRS Bruel, P. E-mail: bechtol@kicp.uchicago.edu [Laboratoire Leprince-Ringuet, École Polytechnique, CNRS and others

    2015-01-20

    The γ-ray sky can be decomposed into individually detected sources, diffuse emission attributed to the interactions of Galactic cosmic rays with gas and radiation fields, and a residual all-sky emission component commonly called the isotropic diffuse γ-ray background (IGRB). The IGRB comprises all extragalactic emissions too faint or too diffuse to be resolved in a given survey, as well as any residual Galactic foregrounds that are approximately isotropic. The first IGRB measurement with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi) used 10 months of sky-survey data and considered an energy range between 200 MeV and 100 GeV. Improvements in event selection and characterization of cosmic-ray backgrounds, better understanding of the diffuse Galactic emission (DGE), and a longer data accumulation of 50 months allow for a refinement and extension of the IGRB measurement with the LAT, now covering the energy range from 100 MeV to 820 GeV. The IGRB spectrum shows a significant high-energy cutoff feature and can be well described over nearly four decades in energy by a power law with exponential cutoff having a spectral index of 2.32 ± 0.02 and a break energy of (279 ± 52) GeV using our baseline DGE model. The total intensity attributed to the IGRB is (7.2 ± 0.6) × 10{sup –6} cm{sup –2} s{sup –1} sr{sup –1} above 100 MeV, with an additional +15%/–30% systematic uncertainty due to the Galactic diffuse foregrounds.

  2. U235: a gamma ray analysis code for uranium isotopic determination

    SciTech Connect

    Clark, D.

    1997-12-01

    A {sup 235}U analysis code, U235, has been written that can nondestructively determine the percentage of {sup 235}U in a uranium sample from the analysis of the emitted gamma rays. The code is operational and work is now underway to improve the accuracy of the calculation, particularly at the high (>90%) and low (<0.7%) {sup 235}U concentrations. A technique has been found to evaluate low {sup 235}U concentrations that works well on the existing standards. Work is now under way to evaluate this technique for other detectors and other types of samples. Work is also proceeding on: (1) ways to better determine gamma backgrounds, (2) techniques to determine the equivalent thickness of the sample to correct for gamma attenuation, (3) evaluation of the existing data base of branching ratios of {sup 235}U, {sup 238}U and their daughters gamma rays to allow better results and (4) evaluation of the existing data base on the emission ratios for uranium, thorium, and protactinium x-rays.

  3. Integral-moment analysis of the BATSE gamma-ray burst intensity distribution

    NASA Technical Reports Server (NTRS)

    Horack, John M.; Emslie, A. Gordon

    1994-01-01

    We have applied the technique of integral-moment analysis to the intensity distribution of the first 260 gamma-ray bursts observed by the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory. This technique provides direct measurement of properties such as the mean, variance, and skewness of the convolved luminosity-number density distribution, as well as associated uncertainties. Using this method, one obtains insight into the nature of the source distributions unavailable through computation of traditional single parameters such as V/V(sub max)). If the luminosity function of the gamma-ray bursts is strongly peaked, giving bursts only a narrow range of luminosities, these results are then direct probes of the radial distribution of sources, regardless of whether the bursts are a local phenomenon, are distributed in a galactic halo, or are at cosmological distances. Accordingly, an integral-moment analysis of the intensity distribution of the gamma-ray bursts provides for the most complete analytic description of the source distribution available from the data, and offers the most comprehensive test of the compatibility of a given hypothesized distribution with observation.

  4. [Signal analysis and spectrum distortion correction for tunable diode laser absorption spectroscopy system].

    PubMed

    Bao, Wei-Yi; Zhu, Yong; Chen, Jun; Chen, Jun-Qing; Liang, Bo

    2011-04-01

    In the present paper, the signal of a tunable diode laser absorption spectroscopy (TDLAS) trace gas sensing system, which has a wavelength modulation with a wide range of modulation amplitudes, is studied based on Fourier analysis method. Theory explanation of spectrum distortion induced by laser intensity amplitude modulation is given. In order to rectify the spectrum distortion, a method of synchronous amplitude modulation suppression by a variable optical attenuator is proposed. To validate the method, an experimental setup is designed. Absorption spectrum measurement experiments on CO2 gas were carried out. The results show that the residual laser intensity modulation amplitude of the experimental system is reduced to -0.1% of its original value and the spectrum distortion improvement is 92% with the synchronous amplitude modulation suppression. The modulation amplitude of laser intensity can be effectively reduced and the spectrum distortion can be well corrected by using the given correction method and system. By using a variable optical attenuator in the TDLAS (tunable diode laser absorption spectroscopy) system, the dynamic range requirements of photoelectric detector, digital to analog converter, filters and other aspects of the TDLAS system are reduced. This spectrum distortion correction method can be used for online trace gas analyzing in process industry.

  5. [Air Dielectric Barrier Discharge Emission Spectrum Measurement and Particle Analysis of Discharge Process].

    PubMed

    Shen, Shuang-yan; Jin, Xing; Zhang, Peng

    2016-02-01

    The emission spectrum detection and diagnosis is one of the most common methods of application to the plasma. It provides wealth of information of the chemical and physical process of the plasma. The analysis of discharge plasma dynamic behavior plays an important role in the study of gas discharge mechanism and application. An air dielectric discharge spectrum measuring device was designed and the emission spectrum data was measured under the experimental condition. The plasma particles evolution was analyzed from the emission spectrum. The numerical calculation model was established and the density equation, energy transfer equation and the Boltzmann equation was coupled to analyze the change of the particle density to explain the emission spectrum characteristics. The results are that the particle density is growing with the increasing of reduced electric field. The particle density is one or two orders of magnitude difference for the same particle at the same moment for the reduced electric field of 40, 60 or 80 Td. A lot of N₂ (A³), N₂ (A³) and N₂ (C³) particles are generated by the electric field excitation. However, it transforms quickly due to the higher energy level. The transformation returns to the balance after the discharge of 10⁻⁶ s. The emission spectrometer measured in the experiments is mostly generated by the transition of excited nitrogen. The peak concentration of O₂ (A¹), O₂ (B¹) and O₂ (A³ ∑⁺u) is not low compared to the excited nitrogen molecules. These particles energy is relatively low and the transition spectral is longer. The spectrometer does not capture the oxygen emission spectrum. And the peak concentration of O particles is small, so the transition emission spectrum is weak. The calculation results of the stabled model can well explain the emission spectrum data.

  6. [Air Dielectric Barrier Discharge Emission Spectrum Measurement and Particle Analysis of Discharge Process].

    PubMed

    Shen, Shuang-yan; Jin, Xing; Zhang, Peng

    2016-02-01

    The emission spectrum detection and diagnosis is one of the most common methods of application to the plasma. It provides wealth of information of the chemical and physical process of the plasma. The analysis of discharge plasma dynamic behavior plays an important role in the study of gas discharge mechanism and application. An air dielectric discharge spectrum measuring device was designed and the emission spectrum data was measured under the experimental condition. The plasma particles evolution was analyzed from the emission spectrum. The numerical calculation model was established and the density equation, energy transfer equation and the Boltzmann equation was coupled to analyze the change of the particle density to explain the emission spectrum characteristics. The results are that the particle density is growing with the increasing of reduced electric field. The particle density is one or two orders of magnitude difference for the same particle at the same moment for the reduced electric field of 40, 60 or 80 Td. A lot of N₂ (A³), N₂ (A³) and N₂ (C³) particles are generated by the electric field excitation. However, it transforms quickly due to the higher energy level. The transformation returns to the balance after the discharge of 10⁻⁶ s. The emission spectrometer measured in the experiments is mostly generated by the transition of excited nitrogen. The peak concentration of O₂ (A¹), O₂ (B¹) and O₂ (A³ ∑⁺u) is not low compared to the excited nitrogen molecules. These particles energy is relatively low and the transition spectral is longer. The spectrometer does not capture the oxygen emission spectrum. And the peak concentration of O particles is small, so the transition emission spectrum is weak. The calculation results of the stabled model can well explain the emission spectrum data. PMID:27209731

  7. The Quantitative Analysis of the Rotational Spectrum of Ncncs

    NASA Astrophysics Data System (ADS)

    Winnewisser, Manfred; Winnewisser, Brenda P.; Medvedev, Ivan R.; De Lucia, Frank C.; Ross, Stephen C.; Koput, Jacek

    2009-06-01

    The analysis of the rotational data which were the basis of our two previous publications about NCNCS as an example of quantum monodromy has been completed, and the data extended to include the 6th excited state of the quasilinear bending mode. This talk will present the results of fitting the data with the GSRB Hamiltonian, which provides structural and potential parameters. Ab initio calculations contributed some parameters that could not be determined from the data. The predicted variation of the expectation value of ρ, which is the complement of the CNC angle, and of the electric dipole transition moment, upon rovibrational excitation indicate the mapping of monodromy in the potential function into these properties of the molecule. B. P. Winnewisser, M. Winnewisser, I. R. Medvedev, M. Behnke, F. C. De Lucia, S. C. Ross and J. Koput Phys. Rev. Lett. 95 (243002), 2005. M. Winnewisser, B. P. Winnewisser, I. R. Medvedev, F. C. De Lucia, S. C. Ross and L. M. Bates J. Mol. Struct. 798 (1-26), 2006.

  8. Non destructive multi elemental analysis using prompt gamma neutron activation analysis techniques: Preliminary results for concrete sample

    SciTech Connect

    Dahing, Lahasen Normanshah; Yahya, Redzuan; Yahya, Roslan; Hassan, Hearie

    2014-09-03

    In this study, principle of prompt gamma neutron activation analysis has been used as a technique to determine the elements in the sample. The system consists of collimated isotopic neutron source, Cf-252 with HPGe detector and Multichannel Analysis (MCA). Concrete with size of 10×10×10 cm{sup 3} and 15×15×15 cm{sup 3} were analysed as sample. When neutrons enter and interact with elements in the concrete, the neutron capture reaction will occur and produce characteristic prompt gamma ray of the elements. The preliminary result of this study demonstrate the major element in the concrete was determined such as Si, Mg, Ca, Al, Fe and H as well as others element, such as Cl by analysis the gamma ray lines respectively. The results obtained were compared with NAA and XRF techniques as a part of reference and validation. The potential and the capability of neutron induced prompt gamma as tool for multi elemental analysis qualitatively to identify the elements present in the concrete sample discussed.

  9. Energy spectrum analysis of blast waves based on an improved Hilbert-Huang transform

    NASA Astrophysics Data System (ADS)

    Li, L.; Wang, F.; Shang, F.; Jia, Y.; Zhao, C.; Kong, D.

    2016-07-01

    Using the improved Hilbert-Huang transform (HHT), this paper investigates the problems of analysis and interpretation of the energy spectrum of a blast wave. It has been previously established that the energy spectrum is an effective feature by which to characterize a blast wave. In fact, the higher the energy spectra in a frequency band of a blast wave, the greater the damage to a target in the same frequency band. However, most current research focuses on analyzing wave signals in the time domain or frequency domain rather than considering the energy spectrum. We propose here an improved HHT method combined with a wavelet packet to extract the energy spectrum feature of a blast wave. When applying the HHT, the signal is first roughly decomposed into a series of intrinsic mode functions (IMFs) by empirical mode decomposition. The wavelet packet method is then performed on each IMF to eliminate noise on the energy spectrum. Second, a coefficient is introduced to remove unrelated IMFs. The energy of each instantaneous frequency can be derived through the Hilbert transform. The energy spectrum can then be obtained by adding up all the components after the wavelet packet filters and screens them through a coefficient to obtain the effective IMFs. The effectiveness of the proposed method is demonstrated by 12 groups of experimental data, and an energy attenuation model is established based on the experimental data. The improved HHT is a precise method for blast wave signal analysis. For other shock wave signals from blasting experiments, an energy frequency time distribution and energy spectrum can also be obtained through this method, allowing for more practical applications.

  10. [Analysis of fluorescence spectrum of petroleum-polluted water].

    PubMed

    Huang, Miao-Fen; Song, Qing-Jun; Xing, Xu-Feng; Jian, Wei-Jun; Liu, Yuan; Zhao, Zu-Long

    2014-09-01

    In four ratio experiments, natural waters, sampled from the mountain reservoir and the sea water around Dalian city, were mixed with the sewage from petroleum refinery and petroleum exploitation plants. The fluorescence spectra of water samples containing only chromophoric dissolved organic matters(CDOM), samples containing only petroleum, and samples containing a mixture of petroleum and CDOM were analyzed, respectively. The purpose of this analysis is to provide a basis for determining the contribution of petroleum substances and CDOM to the total absorption coefficient of the petroleum-contaminated water by using fluorescence technique. The results showed that firstly, CDOM in seawater had three main fluorescence peaks at Ex: 225-230 nm/Em: 320-330 nm, Ex: 280 nm/Em: 340 nm and Ex: 225-240 nm/Em: 430-470 nm, respectively, and these may arise from the oceanic chlorophyll. CDOM in natural reservoir water had two main fluorescence peaks at EX: 240- 260 nm/Em: 420-450 nm and Ex: 310~350 nm/Em: 420--440 nm, respectively, and these may arise from the terrestrial sources; secondly, the water samples containing only petroleum extracted with n-hexane had one to three fluorescence spectral peaksat Ex: 220-240 nm/Em: 320-340 nm, Ex: 270-290 nm/Em: 310-340 nm and Ex: 220-235 nm/Em: 280-310 nm, respectively, caused by their hydrocarbon component; finally, the water samples containing both petroleum and CDOM showed a very strong fluorescence peak at Ex: 230-250 nm/Em: 320-370 nm, caused by the combined effect of CDOM and petroleum hydrocarbons.

  11. [Analysis of fluorescence spectrum of petroleum-polluted water].

    PubMed

    Huang, Miao-Fen; Song, Qing-Jun; Xing, Xu-Feng; Jian, Wei-Jun; Liu, Yuan; Zhao, Zu-Long

    2014-09-01

    In four ratio experiments, natural waters, sampled from the mountain reservoir and the sea water around Dalian city, were mixed with the sewage from petroleum refinery and petroleum exploitation plants. The fluorescence spectra of water samples containing only chromophoric dissolved organic matters(CDOM), samples containing only petroleum, and samples containing a mixture of petroleum and CDOM were analyzed, respectively. The purpose of this analysis is to provide a basis for determining the contribution of petroleum substances and CDOM to the total absorption coefficient of the petroleum-contaminated water by using fluorescence technique. The results showed that firstly, CDOM in seawater had three main fluorescence peaks at Ex: 225-230 nm/Em: 320-330 nm, Ex: 280 nm/Em: 340 nm and Ex: 225-240 nm/Em: 430-470 nm, respectively, and these may arise from the oceanic chlorophyll. CDOM in natural reservoir water had two main fluorescence peaks at EX: 240- 260 nm/Em: 420-450 nm and Ex: 310~350 nm/Em: 420--440 nm, respectively, and these may arise from the terrestrial sources; secondly, the water samples containing only petroleum extracted with n-hexane had one to three fluorescence spectral peaksat Ex: 220-240 nm/Em: 320-340 nm, Ex: 270-290 nm/Em: 310-340 nm and Ex: 220-235 nm/Em: 280-310 nm, respectively, caused by their hydrocarbon component; finally, the water samples containing both petroleum and CDOM showed a very strong fluorescence peak at Ex: 230-250 nm/Em: 320-370 nm, caused by the combined effect of CDOM and petroleum hydrocarbons. PMID:25532346

  12. Analysis method for Thomson scattering diagnostics in GAMMA 10/PDX

    NASA Astrophysics Data System (ADS)

    Ohta, K.; Yoshikawa, M.; Yasuhara, R.; Chikatsu, M.; Shima, Y.; Kohagura, J.; Sakamoto, M.; Nakasima, Y.; Imai, T.; Ichimura, M.; Yamada, I.; Funaba, H.; Minami, T.

    2016-11-01

    We have developed an analysis method to improve the accuracies of electron temperature measurement by employing a fitting technique for the raw Thomson scattering (TS) signals. Least square fitting of the raw TS signals enabled reduction of the error in the electron temperature measurement. We applied the analysis method to a multi-pass (MP) TS system. Because the interval between the MPTS signals is very short, it is difficult to separately analyze each Thomson scattering signal intensity by using the raw signals. We used the fitting method to obtain the original TS scattering signals from the measured raw MPTS signals to obtain the electron temperatures in each pass.

  13. Recovery of macular pigment spectrum in vivo using hyperspectral image analysis

    NASA Astrophysics Data System (ADS)

    Fawzi, Amani A.; Lee, Noah; Acton, Jennifer H.; Laine, Andrew F.; Smith, R. Theodore

    2011-10-01

    We investigated the feasibility of a novel method for hyperspectral mapping of macular pigment (MP) in vivo. Six healthy subjects were recruited for noninvasive imaging using a snapshot hyperspectral system. The three-dimensional full spatial-spectral data cube was analyzed using non-negative matrix factorization (NMF), wherein the data was decomposed to give spectral signatures and spatial distribution, in search for the MP absorbance spectrum. The NMF was initialized with the in vitro MP spectrum and rank 4 spectral signature decomposition was used to recover the MP spectrum and optical density in vivo. The recovered MP spectra showed two peaks in the blue spectrum, characteristic of MP, giving a detailed in vivo demonstration of these absorbance peaks. The peak MP optical densities ranged from 0.08 to 0.22 (mean 0.15+/-0.05) and became spatially negligible at diameters 1100 to 1760 μm (4 to 6 deg) in the normal subjects. This objective method was able to exploit prior knowledge (the in vitro MP spectrum) in order to extract an accurate in vivo spectral analysis and full MP spatial profile, while separating the MP spectra from other ocular absorbers. Snapshot hyperspectral imaging in combination with advanced mathematical analysis provides a simple cost-effective approach for MP mapping in vivo.

  14. A Meta-Analysis of the Reading Comprehension Skills of Individuals on the Autism Spectrum

    ERIC Educational Resources Information Center

    Brown, Heather M.; Oram-Cardy, Janis; Johnson, Andrew

    2013-01-01

    This meta-analysis examined 36 studies comparing autism spectrum disorder (ASD) and control groups in reading comprehension. Three moderators (semantic knowledge, decoding skill, PIQ) and two text types (high vs. low social knowledge) were examined as predictors of reading comprehension in ASD. The overall standardized mean difference for reading…

  15. Exploring the Relationship between Autism Spectrum Disorder and Epilepsy Using Latent Class Cluster Analysis

    ERIC Educational Resources Information Center

    Cuccaro, Michael L.; Tuchman, Roberto F.; Hamilton, Kara L.; Wright, Harry H.; Abramson, Ruth K.; Haines, Jonathan L.; Gilbert, John R.; Pericak-Vance, Margaret

    2012-01-01

    Epilepsy co-occurs frequently in autism spectrum disorders (ASD). Understanding this co-occurrence requires a better understanding of the ASD-epilepsy phenotype (or phenotypes). To address this, we conducted latent class cluster analysis (LCCA) on an ASD dataset (N = 577) which included 64 individuals with epilepsy. We identified a 5-cluster…

  16. Video Modeling for Children and Adolescents with Autism Spectrum Disorder: A Meta-Analysis

    ERIC Educational Resources Information Center

    Thompson, Teresa Lynn

    2014-01-01

    The objective of this research was to conduct a meta-analysis to examine existing research studies on video modeling as an effective teaching tool for children and adolescents diagnosed with Autism Spectrum Disorder (ASD). Study eligibility criteria included (a) single case research design using multiple baselines, alternating treatment designs,…

  17. Facial Structure Analysis Separates Autism Spectrum Disorders into Meaningful Clinical Subgroups

    ERIC Educational Resources Information Center

    Obafemi-Ajayi, Tayo; Miles, Judith H.; Takahashi, T. Nicole; Qi, Wenchuan; Aldridge, Kristina; Zhang, Minqi; Xin, Shi-Qing; He, Ying; Duan, Ye

    2015-01-01

    Varied cluster analysis were applied to facial surface measurements from 62 prepubertal boys with essential autism to determine whether facial morphology constitutes viable biomarker for delineation of discrete Autism Spectrum Disorders (ASD) subgroups. Earlier study indicated utility of facial morphology for autism subgrouping (Aldridge et al. in…

  18. Parents' Perceptions of the Usefulness of Chromosomal Microarray Analysis for Children with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Reiff, Marian; Giarelli, Ellen; Bernhardt, Barbara A.; Easley, Ebony; Spinner, Nancy B.; Sankar, Pamela L.; Mulchandani, Surabhi

    2015-01-01

    Clinical guidelines recommend chromosomal microarray analysis (CMA) for all children with autism spectrum disorders (ASDs). We explored the test's perceived usefulness among parents of children with ASD who had undergone CMA, and received a result categorized as pathogenic, variant of uncertain significance, or negative. Fifty-seven parents…

  19. Innovative Technology-Based Interventions for Autism Spectrum Disorders: A Meta-Analysis

    ERIC Educational Resources Information Center

    Grynszpan, Ouriel; Weiss, Patrice L.; Perez-Diaz, Fernando; Gal, Eynat

    2014-01-01

    This article reports the results of a meta-analysis of technology-based intervention studies for children with autism spectrum disorders. We conducted a systematic review of research that used a pre-post design to assess innovative technology interventions, including computer programs, virtual reality, and robotics. The selected studies provided…

  20. Using the Language Environment Analysis (LENA) System in Preschool Classrooms with Children with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Dykstra, Jessica R.; Sabatos-DeVito, Maura G.; Irvin, Dwight W.; Boyd, Brian A.; Hume, Kara A.; Odom, Sam L.

    2013-01-01

    This study describes the language environment of preschool programs serving children with autism spectrum disorders (ASDs) and examines relationships between child characteristics and an automated measure of adult and child language in the classroom. The Language Environment Analysis (LENA) system was used with 40 children with ASD to collect data…

  1. Evidence-Based Practice: Quality Indicator Analysis of Antecedent Exercise in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Kasner, Melanie; Reid, Greg; MacDonald, Cathy

    2012-01-01

    The purpose of the research was to conduct a quality indicator analysis of studies exploring the effects of antecedent exercise on self-stimulatory behaviors of individuals with autism spectrum disorders (ASD). Educational Resources Information Center (ERIC), Google Scholar, SPORTDiscus, PsychINFO, and PubMed/MedLine databases from 1980 to October…

  2. Confirmatory Factor Analysis of Project Spectrum Activities. A Second-Order "g" Factor or Multiple Intelligences?

    ERIC Educational Resources Information Center

    Castejon, Juan L.; Perez, Antonio M.; Gilar, Raquel

    2010-01-01

    This paper compares different theoretical models of the structure of intelligence, based on the analysis of data obtained in a series of measured abilities corresponding to the Spectrum assessment activities (Gardner, Feldman & Krechevsky, 1998) in a sample of 393 children enrolled in kindergarten and first grade. The data were analyzed using…

  3. Effects of Physical Exercise on Autism Spectrum Disorders: A Meta-Analysis

    ERIC Educational Resources Information Center

    Sowa, Michelle; Meulenbroek, Ruud

    2012-01-01

    It is generally agreed that regular physical exercise promotes physical and mental health, but what are the benefits in people with Autism Spectrum Disorders (ASD)? This meta-analysis evaluates 16 behavioural studies reporting on a total of 133 children and adults with various variants of the syndrome who were offered structured physical…

  4. Transitions, cross sections and neutron binding energy in 186Re by Prompt Gamma Activation Analysis

    NASA Astrophysics Data System (ADS)

    Lerch, A. G.; Hurst, A. M.; Firestone, R. B.; Revay, Zs.; Szentmiklosi, L.; McHale, S. R.; McClory, J. W.; Detwiler, B.; Carroll, J. J.

    2014-03-01

    The nuclide 186Re possesses an isomer with 200,000 year half-life while its ground state has a half-life of 3.718 days. It is also odd-odd and well-deformed nucleus, so should exhibit a variety of other interesting nuclear-structure phenomena. However, the available nuclear data is rather sparse; for example, the energy of the isomer is only known to within + 7 keV and, with the exception of the J?=1- ground state, every proposed level is tentative in the ENSDF. Previously, Prompt Gamma Activation Analysis (PGAA) was utilized to study natRe with 186,188Re being produced via thermal neutron capture. Recently, an enriched 185Re target was irradiated by thermal neutrons at the Budapest Research Reactor to build on those results. Prompt (primary and secondary) and delayed gamma-ray transitions were measured with a large-volume, Compton-suppressed HPGe detector. Absolute cross sections for each gamma transition were deduced and corrected for self attenuation within the sample. Fifty-two primary gamma-ray transitions were newly identified and used to determine a revised value of the neutron binding energy. DICEBOX was used to simulate the decay scheme and the total radiative thermal neutron capture cross section was found to be 97+/-3 b Supported by DTRA (Detwiler) through HDTRA1-08-1-0014.

  5. From Spectrum Analysis to Spectrochemical Analysis: Redefining the Boundary of Spectroscopy

    NASA Astrophysics Data System (ADS)

    Park, Mina

    2007-04-01

    In 1930s-1940s, there were attempts to redefine the boundary of spectroscopy. First, spectroscopists who had been mainly trained as physicists tried to extend an area of spectroscopy beyond physics and physical astronomy by providing diverse examples of how to use spectroscopy in many fields of sciences and industry. Second, some spectroscopists attempted to redefine their professional identity within physics by organizing a new society for applied spectroscopy and trying to separate from optical society. Third, instrument makers helped to decrease resistance for spectroscopy to enter new fields by making more usable spectroscopes for who didn't have expertise in spectroscopy. Why did spectroscopists try these attempts in 1930s-1940s? Why did spectroscopy try to change its boundary within physics and beyond physics? In 1930s, spectroscopists should find out new sets of problems as the golden age of spectroscopy which was brought by quantum mechanics had been over. They found new opportunities in spectrochemical analysis which analyzed materials by spectrum and as spectrochemical analysis was more effective in chemistry, biology and metallurgy rather than in physics, they tried to redefine spectroscopy's boundary and their professional identity. In addition, instrument makers' interests to extend a spectroscopes market also contributed for this change.

  6. The vibrational spectrum and normal coordinate analysis of chlorodifluoromethane, CHClF 2

    NASA Astrophysics Data System (ADS)

    Magill, J. V.; Gough, K. M.; Murphy, W. F.

    The vibrational spectrum of chlorodifluoromethane has been reexamined. The i.r. and Raman spectra of the three isotopic species, 12CHClF 2, 13CHClF 2 and 12CDClF 2, have been obtained with better accuracy and higher resolution than in previous work. An SCF ab initio geometry optimization and quadratic force field calculation have been performed, and this force field has been further optimized to best fit the observed frequencies. The absorption spectrum of the ν 4, 2ν 6 region has been recorded at high resolution (0.002 cm -1) and an analysis of the Fermi resonance perturbation has been carried out.

  7. Analysis of spectrum characteristics of optical scintillation in stack gas flow

    NASA Astrophysics Data System (ADS)

    Liu, Wen-Qing; Liu, He-Lai; Zeng, Zong-Yong; Jiang, Yu

    2006-08-01

    Based on the analysis of spectrum characteristics of intensity fluctuations while light beams pass through stack gas flow in an industrial setting, this paper puts emphasis upon discussing the spectrum of optical intensity fluctuations by the variety of particle concentration in stack gas flow. This paper also gives the primary theoretical explanation of the measurement results in the stack of coal-fired utility boilers. Meanwhile, the cross-correlation formula is given as the theoretical basis of velocity measurement by using particle concentration scintillation.

  8. Piping benchmark problems: dynamic analysis independent support motion response spectrum method

    SciTech Connect

    Bezler, P.; Subudhi, M.; Hartzman, M.

    1985-08-01

    Four benchmark problems and solutions were developed for verifying the adequacy of computer programs used for the dynamic analysis and design of elastic piping systems by the independent support motion, response spectrum method. The dynamic loading is represented by distinct sets of support excitation spectra assumed to be induced by non-uniform excitation in three spatial directions. Complete input descriptions for each problem are provided and the solutions include predicted natural frequencies, participation factors, nodal displacements and element forces for independent support excitation and also for uniform envelope spectrum excitation. Solutions to the associated anchor point pseudo-static displacements are not included.

  9. Gamma isotopic analysis of the coals and ashes from coal fired power plants of Turkey

    NASA Astrophysics Data System (ADS)

    Akyuz, T.; Varinlioglu, A.; Kose, A.

    1999-01-01

    Gamma-isotopic analysis of the ashes produced by the combustion of lignite in power stations of Turkey together with the parent coal samples was performed with the aim to estimate its potential adverse impacts on human health. Gamma-isotopic analysis indicated that all samples contained226Ra (coal samples: 89 148 Bq kg-1; ash samples: 15 26 Bq kg-1),238U (coal samples: 2 4 μg g-1; ash samples: 9 33 μg g-1),232Th (coal samples: 1 9 μg g-1; ash samples: 8 12μg g-1), and40K (coal samples: 26 67 Bq kg-1; ash samples: not detected).134Cs and137Cs have not been found in the samples.

  10. Gamma isotopic analysis of the coals and ashes from coal fired power plants of Turkey

    NASA Astrophysics Data System (ADS)

    Akyuz, T.; Varinlioglu, A.; Kose, A.

    1999-01-01

    Gamma-isotopic analysis of the ashes produced by the combustion of lignite in power stations of Turkey together with the parent coal samples was performed with the aim to estimate its potential adverse impacts on human health. Gamma-isotopic analysis indicated that all samples contained226Ra (coal samples: 89-148 Bq kg-1; ash samples: 15-26 Bq kg-1),238U (coal samples: 2-4 μg g-1; ash samples: 9-33 μg g-1),232Th (coal samples: 1-9 μg g-1; ash samples: 8-12μg g-1), and40K (coal samples: 26-67 Bq kg-1; ash samples: not detected).134Cs and137Cs have not been found in the samples.

  11. [Study on rapid determination and analysis of rocket kerosene by near infrared spectrum and chemometrics].

    PubMed

    Xia, Ben-Li; Cong, Ji-Xin; Li, Xia; Wang, Xuan-Jun

    2011-06-01

    The rocket kerosene quality properties such as density, distillation range, viscosity and iodine value were successfully measured based on their near-infrared spectrum (NIRS) and chemometrics. In the present paper, more than 70 rocket kerosene samples were determined by near infrared spectrum, the models were built using the partial least squares method within the appropriate wavelength range. The correlation coefficients (R2) of every rocket kerosene's quality properties ranged from 0.862 to 0.999. Ten unknown samples were determined with the model, and the result showed that the prediction accuracy of near infrared spectrum method accords with standard analysis requirements. The new method is well suitable for replacing the traditional standard method to rapidly determine the properties of the rocket kerosene.

  12. Determination of the optimum-size californium-252 neutron source for borehole capture gamma-ray analysis

    USGS Publications Warehouse

    Senftle, F.E.; Macy, R.J.; Mikesell, J.L.

    1979-01-01

    The fast- and thermal-neutron fluence rates from a 3.7 ??g 252Cf neutron source in a simulated borehole have been measured as a function of the source-to-detector distance using air, water, coal, iron ore-concrete mix, and dry sand as borehole media. Gamma-ray intensity measurements were made for specific spectral lines at low and high energies for the same range of source-to-detector distances in the iron ore-concrete mix and in coal. Integral gamma-ray counts across the entire spectrum were also made at each source-to-detector distance. From these data, the specific neutron-damage rate, and the critical count-rate criteria, we show that in an iron ore-concrete mix (low hydrogen concentration), 252Cf neutron sources of 2-40 ??g are suitable. The source size required for optimum gamma-ray sensitivity depends on the energy of the gamma ray being measured. In a hydrogeneous medium such as coal, similar measurements were made. The results show that sources from 2 to 20 ??g are suitable to obtain the highest gamma-ray sensitivity, again depending on the energy of the gamma ray being measured. In a hydrogeneous medium, significant improvement in sensitivity can be achieved by using faster electronics; in iron ore, it cannot. ?? 1979 North-Holland Publishing Co.

  13. Online Analysis of {gamma}-ray Sources with H.E.S.S

    SciTech Connect

    Fuessling, M.; Dalton, M.; Kerschhaggl, M.; Schwanke, U.; Jung, I.; Stegmann, C.

    2008-12-24

    Some of the {gamma}-ray sources detected by the H.E.S.S. experiment display irregular, often flare-like emission behaviour. A method to detect these outbursts as fast as possible is highly desirable. At H.E.S.S., first results from an offline analysis of pre-calibrated data can be obtained on-site approximately one hour after run end. We present a development and implementation of online analysis software that performs calibration and analysis of data at the time they are being taken allowing for a fast confirmation of observational results and appropriate reaction by the on-site shift crew.

  14. Attenuation analysis of real GPR wavelets: The equivalent amplitude spectrum (EAS)

    NASA Astrophysics Data System (ADS)

    Economou, Nikos; Kritikakis, George

    2016-03-01

    Absorption of a Ground Penetrating Radar (GPR) pulse is a frequency dependent attenuation mechanism which causes a spectral shift on the dominant frequency of GPR data. Both energy variation of GPR amplitude spectrum and spectral shift were used for the estimation of Quality Factor (Q*) and subsequently the characterization of the subsurface material properties. The variation of the amplitude spectrum energy has been studied by Spectral Ratio (SR) method and the frequency shift by the estimation of the Frequency Centroid Shift (FCS) or the Frequency Peak Shift (FPS) methods. The FPS method is more automatic, less robust. This work aims to increase the robustness of the FPS method by fitting a part of the amplitude spectrum of GPR data with Ricker, Gaussian, Sigmoid-Gaussian or Ricker-Gaussian functions. These functions fit different parts of the spectrum of a GPR reference wavelet and the Equivalent Amplitude Spectrum (EAS) is selected, reproducing Q* values used in forward Q* modeling analysis. Then, only the peak frequencies and the time differences between the reference wavelet and the subsequent reflected wavelets are used to estimate Q*. As long as the EAS is estimated, it is used for Q* evaluation in all the GPR section, under the assumption that the selected reference wavelet is representative. De-phasing and constant phase shift, for obtaining symmetrical wavelets, proved useful in the sufficiency of the horizons picking. Synthetic, experimental and real GPR data were examined in order to demonstrate the effectiveness of the proposed methodology.

  15. [Experiments of micro-distance measurement for GMLM with spectrum analysis method].

    PubMed

    Zhang, Jie; Huang, Shang-Lian; Zhang, Zhi-Hai; Sun, Ji-Yong; Shi, Ling-Na; Zhu, Yong

    2008-07-01

    Projection display devices are undergoing a period of multi-development, and with the maturation of MEMS technology, which leads to MEMS-based light modulators for display applications, have become one of the research focuses. The structure of MEMS-based grating moving light modulator (GMLM) is composed of the reflection plate, address electrode and four cantilevers, and movable grating plate, which is supported by four crab-cantilevers placed around, and is actuated like a piston by electrostatic force. The piston-type motion of grating can be used to modulate the phase of incident light. The micro-distance between the upper surface of movable grating and underlying reflector is a key parameter and is important to GMLM performance. Traditional measurement method such as step-machine would destroy the device; while a high accuracy and non-contact measurement machine called KYKO White Light Interferometer is expensive. In the present paper, the GMLM optical principle using scalar diffraction theory was in details analyzed. A novel non-contact wavelength scanning spectrum analysis method was put forward to measure the distance between the upper surface of movable grating and underlying reflector. The U-4100 spectrophotometer was adopted to gain spectrum information; while the spectrum analysis method using peak wavelength position was introduced to calculate the micro distance. The measurement result is consistent to theoretical result. The micro-distance is 1.131 3 microm using such non-contact wavelength scanning spectrum analysis method, while it is 1.240 0 microm with WYKO White Light Interferometer. The relative error was lower than 1%, compared with the results measured by WYKO White Light Interferometer, and the method has good repetition ability and is cheap with RMB50 Yuan each time. Furthermore, measuring pull-in voltage, resonance frequency and micro distance in MEMS-based diffraction and interference devices was proposed completely based on such non

  16. Gamma-gamma colliders

    SciTech Connect

    Kim, K.J.; Sessler, A.

    1996-06-01

    Gamma-gamma colliders make intense beams of gamma rays and have them collide so as to make elementary particles. The authors show, in this article, that constructing a gamma-gamma collider as an add-on to an electron-positron linear collider is possible with present technology and that it does not require much additional cost. Furthermore, they show that the resulting capability is very interesting from a particle physics point of view. An overview of a linear collider, with a second interaction region devoted to {gamma}{gamma} collisions is shown.

  17. MAGIC gamma-ray and multi-frequency observations of flat spectrum radio quasar PKS 1510-089 in early 2012

    NASA Astrophysics Data System (ADS)

    Aleksić, J.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Babic, A.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Carmona, E.; Carosi, A.; Carreto Fidalgo, D.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Caneva, G.; De Lotto, B.; Delgado Mendez, C.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher, D.; Elsaesser, D.; Farina, E.; Ferenc, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Godinović, N.; González Muñoz, A.; Gozzini, S. R.; Hadasch, D.; Hayashida, M.; Herrera, J.; Herrero, A.; Hildebrand, D.; Hose, J.; Hrupec, D.; Idec, W.; Kadenius, V.; Kellermann, H.; Kodani, K.; Konno, Y.; Krause, J.; Kubo, H.; Kushida, J.; La Barbera, A.; Lelas, D.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López, M.; López-Coto, R.; López-Oramas, A.; Lorenz, E.; Lozano, I.; Makariev, M.; Mallot, K.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moralejo, A.; Munar-Adrover, P.; Nakajima, D.; Niedzwiecki, A.; Nilsson, K.; Nishijima, K.; Noda, K.; Nowak, N.; Orito, R.; Overkemping, A.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Partini, S.; Persic, M.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Preziuso, S.; Puljak, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rodriguez Garcia, J.; Rügamer, S.; Saggion, A.; Saito, T.; Saito, K.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Stamatescu, V.; Stamerra, A.; Steinbring, T.; Storz, J.; Strzys, M.; Sun, S.; Surić, T.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Thaele, J.; Tibolla, O.; Torres, D. F.; Toyama, T.; Treves, A.; Uellenbeck, M.; Vogler, P.; Wagner, R. M.; Zandanel, F.; Zanin, R.; MAGIC Collaboration; Lucarelli, F.; Pittori, C.; Vercellone, S.; Verrecchia, F.; AGILE Collaboration; Buson, S.; D'Ammando, F.; Stawarz, L.; Giroletti, M.; Orienti, M.; Fermi-LAT Collaboration; Mundell, C.; Steele, I.; Zarpudin, B.; Raiteri, C. M.; Villata, M.; Sandrinelli, A.; Lähteenmäki, A.; Tammi, J.; Tornikoski, M.; Hovatta, T.; Readhead, A. C. S.; Max-Moerbeck, W.; Richards, J. L.; Jorstad, S.; Marscher, A.; Gurwell, M. A.; Larionov, V. M.; Blinov, D. A.; Konstantinova, T. S.; Kopatskaya, E. N.; Larionova, L. V.; Larionova, E. G.; Morozova, D. A.; Troitsky, I. S.; Mokrushina, A. A.; Pavlova, Yu. V.; Chen, W. P.; Lin, H. C.; Panwar, N.; Agudo, I.; Casadio, C.; Gómez, J. L.; Molina, S. N.; Kurtanidze, O. M.; Nikolashvili, M. G.; Kurtanidze, S. O.; Chigladze, R. A.; Acosta-Pulido, J. A.; Carnerero, M. I.; Manilla-Robles, A.; Ovcharov, E.; Bozhilov, V.; Metodieva, I.; Aller, M. F.; Aller, H. D.; Fuhrman, L.; Angelakis, E.; Nestoras, I.; Krichbaum, T. P.; Zensus, J. A.; Ungerechts, H.; Sievers, A.

    2014-09-01

    Aims: Amongst more than fifty blazars detected in very high energy (VHE, E> 100 GeV) γ rays, only three belong to the subclass of flat spectrum radio quasars (FSRQs). The detection of FSRQs in the VHE range is challenging, mainly because of their soft spectra in the GeV-TeV regime. MAGIC observed PKS 1510-089 (z = 0.36) starting 2012 February 3 until April 3 during a high activity state in the high energy (HE, E> 100 MeV) γ-ray band observed by AGILE and Fermi. MAGIC observations result in the detection of a source with significance of 6.0 standard deviations (σ). We study the multi-frequency behaviour of the source at the epoch of MAGIC observation, collecting quasi-simultaneous data at radio and optical (GASP-WEBT and F-Gamma collaborations, REM, Steward, Perkins, Liverpool, OVRO, and VLBA telescopes), X-ray (Swift satellite), and HE γ-ray frequencies. Methods: We study the VHE γ-ray emission, together with the multi-frequency light curves, 43 GHz radio maps, and spectral energy distribution (SED) of the source. The quasi-simultaneous multi-frequency SED from the millimetre radio band to VHE γ rays is modelled with a one-zone inverse Compton model. We study two different origins of the seed photons for the inverse Compton scattering, namely the infrared torus and a slow sheath surrounding the jet around the Very Long Baseline Array (VLBA) core. Results: We find that the VHE γ-ray emission detected from PKS 1510-089 in 2012 February-April agrees with the previous VHE observations of the source from 2009 March-April. We find no statistically significant variability during the MAGIC observations on daily, weekly, or monthly time scales, while the other two known VHE FSRQs (3C 279 and PKS 1222+216) have shown daily scale to sub-hour variability. The γ-ray SED combining AGILE, Fermi and MAGIC data joins smoothly and shows no hint of a break. The multi-frequency light curves suggest a common origin for the millimetre radio and HE γ-ray emission, and the HE

  18. N-SAP and G-SAP neutron and gamma ray albedo model scatter shield analysis program

    NASA Technical Reports Server (NTRS)

    Sapovchak, B. J.; Stephenson, L. D.

    1967-01-01

    Computer program calculates neutron or gamma ray first order scattering from a plane or cylindrical surface to a detector point. The SAP Codes, G-SAP and N-SAP, constitute a multiple scatter albedo model shield analysis.

  19. [The Study about Spectrum Characteristic Analysis Method in the Induction Period of Gas Explosion Flame].

    PubMed

    Liu, Kui; Li, Xiao-bin; Zheng, Dan

    2015-08-01

    Through analyzing the spectroscopic data of gas explosion flame whose volume fraction is 10% under a small scale experimental condition based on the target emission spectrum analysis methods; presents the gas explosion flame spectrum characteristic analysis methods about frequency domain feature parameters which include spectral density, band radiation light intensity, band average deviation, the time domain characteristic parameter which include band radiation energy, time average and deviation and the characteristic parameters which include skewness, kurtosis and half width; obtain the results that in the vicinity of somewhere, the spectral density converts between positive and negative in the range of 1 nm that the light intensity of gas explosion flame changes dramatically; the definite integral of gas explosion flame spectral waveband is strongest in the 550~900 nm; with the wavelength increases the detected time grow, the gas explosion flame spectral signal strength attenuation trends on the whole and after the peak interval appeared in the process of decay have weaken the strength of the enhanced; results show tha the target emission spectrum analysis methods can be applied to do the semi-quantitative analysis of dynamic process of gas explosion, the analysis spectral characteristics can be taken as a standard to detecting gas explosion flame.

  20. EPR investigation of some gamma-irradiated excipients

    NASA Astrophysics Data System (ADS)

    Aleksieva, Katerina; Yordanov, Nicola D.

    2012-09-01

    The results of electron paramagnetic resonance (EPR) studies on some excipients: lactose, microcrystalline cellulose (avicel), starch, dioxosilane (aerosil), talc and magnesium stearate before and after gamma-irradiation are reported. Before irradiation, all samples are EPR silent except talc. After gamma-irradiation, they show complex spectra except magnesium stearate, which is EPR silent. Studies show the influence of gamma-irradiation on EPR spectra and stability of gamma-induced radicals. Analysis of the EPR spectrum of gamma-irradiated talc shows that this material is radiation insensitive. Only lactose forms stable-free radicals upon gamma sterilization and can be used for identification of radiation processing for a long time period thereafter.

  1. Spectrum analysis of seismic surface waves and its applications in seismic landmine detection.

    PubMed

    Alam, Mubashir; McClellan, James H; Scott, Waymond R

    2007-03-01

    In geophysics, spectrum analysis of surface waves (SASW) refers to a noninvasive method for soil characterization. However, the term spectrum analysis can be used in a wider sense to mean a method for determining and identifying various modes of seismic surface waves and their properties such as velocity, polarization, etc. Surface waves travel along the free boundary of a medium and can be easily detected with a transducer placed on the free surface of the boundary. A new method based on vector processing of space-time data obtained from an array of triaxial sensors is proposed to produce high-resolution, multimodal spectra from surface waves. Then individual modes can be identified in the spectrum and reconstructed in the space-time domain; also, reflected waves can be separated easily from forward waves in the spectrum domain. This new SASW method can be used for detecting and locating landmines by analyzing the reflected waves for resonance. Processing examples are presented for numerically generated data, experimental data collected in a laboratory setting, and field data.

  2. In situ capture gamma-ray analysis of coal in an oversize borehole

    USGS Publications Warehouse

    Mikesell, J.L.; Dotson, D.W.; Senftle, F.E.; Zych, R.S.; Koger, J.; Goldman, L.

    1983-01-01

    In situ capture gamma-ray analysis in a coal seam using a high resolution gamma-ray spectrometer in a close-fitting borehole has been reported previously. In order to check the accuracy of the method under adverse conditions, similar measurements were made by means of a small-diameter sonde in an oversize borehole in the Pittsburgh seam, Greene County, Pennsylvania. The hole was 5 times the diameter of the sonde, a ratio that substantially increased the contribution of water (hydrogen) to the total spectral count and reduced the size of the sample measured by the detector. The total natural count, the 40K,count, and the intensities of capture gamma rays from Si, Ca, H, and Al were determined as a function of depth above, through, and below the coal seam. From these logs, the depth and width of the coal seam and its partings were determined. Spectra were accumulated in the seam for 1 h periods by using neutron sources of different strengths. From the spectra obtained by means of several 252Cf neutron sources of different sizes, the ultimate elemental analysis and ash content were determined. The results were not as good as those obtained previously in a close-fitting borehole. However, the results did improve with successively larger source-to-detector distances, i.e.,as the count contribution due to hydrogen in the water decreased. It was concluded that in situ borehole analyses should be made in relatively close-fitting boreholes. ?? 1983.

  3. Single orthogonal sinusoidal grating for gamma correction in digital projection phase measuring profilometry

    NASA Astrophysics Data System (ADS)

    Xiao, Yanshan; Cao, Yiping; Wu, Yingchun; Shi, Shunping

    2013-05-01

    The gamma nonlinearity of the digital projector leads to obvious phase errors in the phase measuring profilometry. Based on the Fourier spectrum analysis of the captured pattern, a robust gamma correction method is proposed in this paper. An orthogonal sinusoidal grating precoded with two different known gamma values is used to evaluate the gamma value of the pattern. The evaluated gamma value is then encoded into the computer-generated phase-shifting fringe patterns before the fringe patterns are sent to the digital projector, which makes the captured fringe patterns well-sinusoidal and alleviates the phase errors caused by the gamma nonlinearity. Compared with other gamma correction methods, only one captured pattern is needed to evaluate the gamma value without loss of the accuracy. With the proposed method, a fast and accurate three-dimensional shape measurement can be achieved using the conventional three-step phase-shifting algorithm. Experiments have verified its feasibility and validity.

  4. Development of isotope dilution gamma-ray spectrometry for plutonium analysis

    SciTech Connect

    Li, T.K.; Parker, J.L. ); Kuno, Y.; Sato, S.; Kurosawa, A.; Akiyama, T. )

    1991-01-01

    We are studying the feasibility of determining the plutonium concentration and isotopic distribution of highly radioactive, spent-fuel dissolver solutions by employing high-resolution gamma-ray spectrometry. The study involves gamma-ray plutonium isotopic analysis for both dissolver and spiked dissolver solution samples, after plutonium is eluted through an ion-exchange column and absorbed in a small resin bead bag. The spike is well characterized, dry plutonium containing {approximately}98% of {sup 239}Pu. By using measured isotopic information, the concentration of elemental plutonium in the dissolver solution can be determined. Both the plutonium concentration and the isotopic composition of the dissolver solution obtained from this study agree well with values obtained by traditional isotope dilution mass spectrometry (IDMS). Because it is rapid, easy to operate and maintain, and costs less, this new technique could be an alternative method to IDMS for input accountability and verification measurements in reprocessing plants. 7 refs., 4 figs., 4 tabs.

  5. A feasibility study of the in vivo prompt gamma activation analysis using a mobile nuclear reactor.

    PubMed

    Chung, C; Yuan, L J; Chen, K B; Weng, P S; Chang, P S; Ho, Y H

    1985-05-01

    A facility for in vivo prompt gamma activation analysis using moderated neutron beams from a 0.1 W mobile nuclear reactor is described. The low-power nuclear reactor provides total neutron flux of 3.3 X 10(4)n cm-2 s-1 on the surface of a vertical beam tube to which a liquid phantom is positioned. The capability of such a partial-body irradiation facility is demonstrated by measuring trace amounts of toxic cadmium in kidney. The detection limit of Cd in kidney for a skin dose of 1.66 mSv (166 mrem) is 1.34 mg under 500 s irradiation. This facility therefore combines the advantages of mobility with high sensitivity of detection of a toxic element under low neutron and gamma doses.

  6. Event-sequence time series analysis in ground-based gamma-ray astronomy

    SciTech Connect

    Barres de Almeida, U.; Chadwick, P.; Daniel, M.; Nolan, S.; McComb, L.

    2008-12-24

    The recent, extreme episodes of variability detected from Blazars by the leading atmospheric Cerenkov experiments motivate the development and application of specialized statistical techniques that enable the study of this rich data set to its furthest extent. The identification of the shortest variability timescales supported by the data and the actual variability structure observed in the light curves of these sources are some of the fundamental aspects being studied, that answers can bring new developments on the understanding of the physics of these objects and on the mechanisms of production of VHE gamma-rays in the Universe. Some of our efforts in studying the time variability of VHE sources involve the application of dynamic programming algorithms to the problem of detecting change-points in a Poisson sequence. In this particular paper we concentrate on the more primary issue of the applicability of counting statistics to the analysis of time-series on VHE gamma-ray astronomy.

  7. Diffuse continuum gamma rays from the Galaxy observed by COMPTEL

    NASA Technical Reports Server (NTRS)

    Strong, A. W.; Bennett, K.; Bloemen, H.; Diehl, R.; Hermsen, W.; Morris, D.; Schonfelder, V.; Stacy, J. G.; De Vries, C.; Varendorff, M.

    1994-01-01

    The diffuse Galactic continuum gamma-ray emission has been studied using the full Sky Survey from COMPTEL on the Compton Observatory CGRO. The diffuse emission appears to be visible in the whole 0.75-30 MeV range covered by the instrument, although a considerable contribution from unresolved point sources cannot be excluded. A correlation analysis using HI and CO surveys of the Galaxy is used to derive the Galactic emissivity spectrum, and this is consistent with a smooth continuation to the spectrum at higher energies derived by a similar analysis of COS-B data. The apparent conversion factor from integrated CO temperature to molecular hydrogen column density can also be determined from the correlation analysis. The value obtained is consistent with results from COS-B and other non-gamma-ray methods. Calculations of the emissivity spectrum from bremsstrahlung from a cosmic-ray electron spectrum based on propagation models are compared with the observations.

  8. Principal Component Analysis of Long-Lag,Wide-Pulse Gamma-Ray Burst Data

    NASA Astrophysics Data System (ADS)

    Peng, Zhao-Yang; Liu, Wen-Shuai

    2014-09-01

    We have carried out a Principal Component Analysis (PCA) of the temporal and spectral variables of 24 long-lag, wide-pulse gamma-ray bursts (GRBs) presented by Norris et al. (2005). Taking all eight temporal and spectral parameters into account, our analysis shows that four principal components are enough to describe the variation of the temporal and spectral data of long-lag bursts. In addition, the first-two principal components are dominated by the temporal variables while the third and fourth principal components are dominated by the spectral parameters.

  9. Functional pitch of a liver: fatty liver disease diagnosis with photoacoustic spectrum analysis

    NASA Astrophysics Data System (ADS)

    Xu, Guan; Meng, Zhuoxian; Lin, Jiandie; Carson, Paul; Wang, Xueding

    2014-03-01

    To provide more information for classification and assessment of biological tissues, photoacoustic spectrum analysis (PASA) moves beyond the quantification of the intensities of the photoacoustic (PA) signals by the use of the frequency-domain power distribution, namely power spectrum, of broadband PA signals. The method of PASA quantifies the linear-fit to the power spectrum of the PA signals from a biological tissue with 3 parameters, including intercept, midband-fit and slope. Intercept and midband-fit reflect the total optical absorption of the tissues whereas slope reflects the heterogeneity of the tissue structure. Taking advantage of the optical absorption contrasts contributed by lipid and blood at 1200 and 532 nm, respectively and the heterogeneous tissue microstructure in fatty liver due to the lipid infiltration, we investigate the capability of PASA in identifying histological changes of fatty livers in mouse model. 6 and 9 pairs of normal and fatty liver tissues from rat models were examined by ex vivo experiment with a conventional rotational PA measurement system. One pair of rat models with normal and fatty livers was examined non-invasively and in situ with our recently developed ultrasound and PA parallel imaging system. The results support our hypotheses that the spectrum analysis of PA signals can provide quantitative measures of the differences between the normal and fatty liver tissues and that part of the PA power spectrum can suffice for characterization of microstructures in biological tissues. Experimental results also indicate that the vibrational absorption peak of lipid at 1200nm could facilitate fatty liver diagnosis.

  10. [Study on spectrum analysis of X-ray based on rotational mass effect in special relativity].

    PubMed

    Yu, Zhi-Qiang; Xie, Quan; Xiao, Qing-Quan

    2010-04-01

    Based on special relativity, the formation mechanism of characteristic X-ray has been studied, and the influence of rotational mass effect on X-ray spectrum has been given. A calculation formula of the X-ray wavelength based upon special relativity was derived. Error analysis was carried out systematically for the calculation values of characteristic wavelength, and the rules of relative error were obtained. It is shown that the values of the calculation are very close to the experimental values, and the effect of rotational mass effect on the characteristic wavelength becomes more evident as the atomic number increases. The result of the study has some reference meaning for the spectrum analysis of characteristic X-ray in application.

  11. Electrospray ionization time-of-flight mass spectrum analysis method of polyaluminum chloride flocculants.

    PubMed

    Feng, Chenghong; Bi, Zhe; Tang, Hongxiao

    2015-01-01

    Electrospray mass spectrometry has been reported as a novel technique for Al species identification, but to date, the working mechanism is not clear and no unanimous method exists for spectrum analysis of traditional Al salt flocculants, let alone for analysis of polyaluminum chloride (PAC) flocculants. Therefore, this paper introduces a novel theoretical calculation method to identify Al species from a mass spectrum, based on deducing changes in m/z (mass-to-charge ratio) and molecular formulas of oligomers in five typical PAC flocculants. The use of reference chemical species was specially proposed in the method to guarantee the uniqueness of the assigned species. The charge and mass reduction of the Al cluster was found to proceed by hydrolysis, gasification, and change of hydroxyl on the oxy bridge. The novel method was validated both qualitatively and quantitatively by comparing the results to those obtained with the (27)Al NMR spectrometry.

  12. [Study on spectrum analysis of X-ray based on rotational mass effect in special relativity].

    PubMed

    Yu, Zhi-Qiang; Xie, Quan; Xiao, Qing-Quan

    2010-04-01

    Based on special relativity, the formation mechanism of characteristic X-ray has been studied, and the influence of rotational mass effect on X-ray spectrum has been given. A calculation formula of the X-ray wavelength based upon special relativity was derived. Error analysis was carried out systematically for the calculation values of characteristic wavelength, and the rules of relative error were obtained. It is shown that the values of the calculation are very close to the experimental values, and the effect of rotational mass effect on the characteristic wavelength becomes more evident as the atomic number increases. The result of the study has some reference meaning for the spectrum analysis of characteristic X-ray in application. PMID:20545180

  13. [Observation and analysis of solar ultraviolet irradiance spectrum in Chengdu area].

    PubMed

    Sun, Peng; He, Jie; Zhao, Xiao-Yan; Zuo, Hao-Yi; Yang, Jing-Guo

    2008-04-01

    The solar ultraviolet irradiance spectrum in Chengdu area from March to July in 2006 was observed with an ultraviolet CCD optical multi-channel analyzer. According to the observation results, some analysis of the basic characteristics was made. The analysis of the solar ultraviolet irradiance spectrum showed that the solar ultraviolet irradiance is weak in the morning and in the evening but strong at noon, reaches the strongest point in June, and reversely correlates with the change in SZA (solar zenith angle); the ratio of irradiance flux of UVB to UVA is less than 0.04, and usually, the ratio in the afternoon is bigger than that in the morning in sunny days; Fogs can cause the ratio to increase, the reason is that fogs show stronger influence on attenuation of UVA than UVB; Clouds absorbed the solar ultraviolet irradiance greatly.

  14. Analysis of the infrared spectrum and microstructure of hardened cement paste

    SciTech Connect

    Gao, X.F.; Lo, Y.; Tam, C.M.; Chung, C.Y. )

    1999-06-01

    Phase transformation was found in hardened cement paste exposed to dynamic loading caused by typhoon and the normal static-dynamic loading. The concrete samples were obtained from a 20-year-old residential building. The bonding characteristics and microstructure of the hardened cement paste with different loading history have been carefully studied using scanning electron microscopy analysis and infrared spectrum technique. The scanning electron microscopy micrographs indicate that there is a morphological difference in the concrete microstructure. The infrared spectrum analysis has provided information for understanding the phase transformation characteristics of the primary bonds and secondary bonds. This has led to the establishment of a microscopic model describing the correlation between the behavior of the hydrate lime and the properties of the hardened cement paste.

  15. Distributed optical fiber vibration sensor based on spectrum analysis of Polarization-OTDR system.

    PubMed

    Zhang, Ziyi; Bao, Xiaoyi

    2008-07-01

    A fully distributed optical fiber vibration sensor is demonstrated based on spectrum analysis of Polarization-OTDR system. Without performing any data averaging, vibration disturbances up to 5 kHz is successfully demonstrated in a 1km fiber link with 10m spatial resolution. The FFT is performed at each spatial resolution; the relation of the disturbance at each frequency component versus location allows detection of multiple events simultaneously with different and the same frequency components.

  16. Phase velocity spectrum analysis for a time delay comb transducer for guided wave mode excitation

    SciTech Connect

    Quarry, M J; Rose, J L

    2000-09-26

    A theoretical model for the analysis of ultrasonic guided wave mode excitation of a comb transducer with time delay features was developed. Time delay characteristics are included via a Fourier transform into the frequency domain. The phase velocity spectrum can be used to determine the mode excitation on the phase velocity dispersion curves for a given structure. Experimental and theoretical results demonstrate the tuning of guided wave modes using a time delay comb transducer.

  17. Closed form analysis of a gamma, back-to-back free displacer Stirling engine

    SciTech Connect

    Lewis, K.L.; Kilgour, D.B.; Lazarides, Y.G.; Rallis, C.J.

    1983-08-01

    A back-to-back, free displacer, gamma type Stirling engine has been designed and is currently under manufacture and development at the University of the Witwatersrand. This paper presents a simple idealized analysis for such an engine. It involves the coupling together of the thermodynamic and mechanical equations, and by the use of classical control and vibration theory, closed form solutions are obtained. This work follows up on previous methods of analysis developed by Berchowitz, WyattMair and Goldberg for similar types of engines. A numerical application of the analysis has been carried out for the design in order to evaluate the operating frequency, phase displacements, amplitude of oscillation and basic output power. Performance characteristics are obtained and detailed in the paper. The analysis has provided analytic proof of the viability of the proposed engine configuration, highlighted weak areas and provided a background to higher order analysis. A programme of experimental validation is under way.

  18. Mutation analysis of the NSD1 gene in patients with autism spectrum disorders and macrocephaly

    PubMed Central

    Buxbaum, Joseph D; Cai, Guiqing; Nygren, Gudrun; Chaste, Pauline; Delorme, Richard; Goldsmith, Juliet; Råstam, Maria; Silverman, Jeremy M; Hollander, Eric; Gillberg, Christopher; Leboyer, Marion; Betancur, Catalina

    2007-01-01

    Background Sotos syndrome is an overgrowth syndrome characterized by macrocephaly, advanced bone age, characteristic facial features, and learning disabilities, caused by mutations or deletions of the NSD1 gene, located at 5q35. Sotos syndrome has been described in a number of patients with autism spectrum disorders, suggesting that NSD1 could be involved in other cases of autism and macrocephaly. Methods We screened the NSD1 gene for mutations and deletions in 88 patients with autism spectrum disorders and macrocephaly (head circumference 2 standard deviations or more above the mean). Mutation analysis was performed by direct sequencing of all exons and flanking regions. Dosage analysis of NSD1 was carried out using multiplex ligation-dependent probe amplification. Results We identified three missense variants (R604L, S822C and E1499G) in one patient each, but none is within a functional domain. In addition, segregation analysis showed that all variants were inherited from healthy parents and in two cases were also present in unaffected siblings, indicating that they are probably nonpathogenic. No partial or whole gene deletions/duplications were observed. Conclusion Our findings suggest that Sotos syndrome is a rare cause of autism spectrum disorders and that screening for NSD1 mutations and deletions in patients with autism and macrocephaly is not warranted in the absence of other features of Sotos syndrome. PMID:18001468

  19. Predicting Flaw-Induced Resonance Spectrum Shift with Theoretical Perturbation Analysis

    SciTech Connect

    Lai, Canhai; Sun, Xin

    2013-10-28

    Resonance inspection is an emerging non-destructive evaluation (NDE) technique which uses the resonance spectra differences between the good part population and the flawed parts to identify anomalous parts. It was previously established that finite-element (FE)-based modal analysis can be used to predict the resonance spectrum for an engineering scale part with relatively good accuracy. However, FE-based simulations can be time consuming in examining the spectrum shifts induced by all possible structural flaws. This paper aims at developing a computationally efficient perturbation technique to quantify the frequency shifts induced by small structural flaws, based on the FE simulated resonance spectrum for the perfect part. A generic automotive connecting rod is used as the example part for our study. The results demonstrate that the linear perturbation theory provides a very promising way in predicting frequency changes induced by small structural flaws. As the flaw size increases, the discrepancy between the perturbation analysis and the actual FE simulation results increases due to nonlinearity, yet the perturbation analysis is still able to predict the right trend in frequency shift.

  20. Predicting flaw-induced resonance spectrum shift with theoretical perturbation analysis

    NASA Astrophysics Data System (ADS)

    Lai, C.; Sun, X.

    2013-10-01

    Resonance inspection is an emerging non-destructive evaluation (NDE) technique used by the automotive casting industry which uses the resonance spectra differences between the good part population and the flawed parts to identify anomalous parts. It was previously established that finite-element (FE)-based modal analysis can be used to predict the resonance spectrum for an engineering scale part with relatively good accuracy. However, FE-based simulations can be time consuming in examining the spectrum shifts induced by all possible structural flaws. This paper aims at developing a computationally efficient perturbation technique to quantify the frequency shifts induced by small structural flaws, based on the FE simulated resonance spectrum for the perfect part. A generic automotive connecting rod is used as the example part for our study. The results demonstrate that the linear perturbation theory provides a very promising way in predicting frequency changes induced by small structural flaws. As the flaw size increases, the discrepancy between the perturbation analysis and the actual FE simulation results increases due to nonlinearity, yet the perturbation analysis is still able to predict the right trend in frequency shift.

  1. Characterization of multiple prompt gamma-ray analysis (MPGA) system at JAEA for elemental analysis of geological and cosmochemical samples.

    PubMed

    Islam, M A; Ebihara, M; Toh, Y; Murakami, Y; Harada, H

    2012-08-01

    The newly installed multiple prompt gamma-ray analysis (MPGA) system at the Japan Atomic Energy Agency (JAEA) was characterized for nondestructive multi-element analysis of geological and cosmochemical samples. Analysis of the hydrogenous meteorite Orgueil by both MPGA and PGA implies that MPGA can be used for elemental determination with sufficient accuracy. For some elements which cannot be determined by conventional PGA due to the spectral interference or lower sensitivity, it was shown that they could be determined by MPGA. PMID:22732386

  2. Gamma scintigraphic analysis of albumin flux in patients with acute respiratory distress syndrome

    SciTech Connect

    Sugerman, H.J.; Tatum, J.L.; Burke, T.S.; Strash, A.M.; Glauser, F.L.

    1984-06-01

    Computerized gamma-scintigraphy provides a new method for the analysis of albumin flux in patients with pulmonary permeability edema. In this technique, 10 mCi of /sup 99/mTc -tagged human serum albumin is administered and lung:heart radioactivity ratios are determined. This ratio remains constant unless there is a leak of albumin, when a rising ratio with time, called the ''slope index'' (SI), is seen. Thirty-five scintigraphic studies were obtained in 28 patients by means of a portable computerized gamma-camera. Thirteen of these patients had clinical evidence of the acute respiratory distress syndrome (ARDS) and six had or were recovering from left ventricular induced congestive heart failure (CHF). Five of the patients with CHF and pulmonary capillary wedge pressure (PCWP) below 30 mm Hg had normal scintigraphic studies. The patients with ARDS were found to have significantly higher SIs than patients who did not have, or had recovered from, ARDS. Positive SIs were present from 1 to 8 days following the apparent onset of ARDS in seven studies in five patients. Recovery of gas exchange was associated with a return to a normal SI in four patients. In conclusion, computerized gamma-scintigraphy was a sensitive, noninvasive tool for the detection of a pathologic increase in pulmonary protein flux. Positive scintigraphic findings were associated with significantly impaired gas exchange. The method documented that the leak of albumin in patients with ARDS may last for days but resolves with recovery.

  3. Prompt gamma-ray analysis using cold and thermal guided neutron beams at JAERI.

    PubMed

    Yonezawa, C

    1999-01-01

    A highly sensitive neutron-induced prompt gamma-ray analysis (PGA) system, usable at both cold and thermal neutron beam guides of JRR-3M, has been constructed. The system was designed to achieve the lowest gamma-ray background by using lithium fluoride tiles as neutron shielding, by placing the samples in a He atmosphere and by using a Ge-bismuth germanate detector system for Compton suppression. The gamma-ray spectrometer can acquire three modes of spectra simultaneously: single, Compton suppression, and pair modes. Because of the low-energy guided neutron beams and the low-background system, analytical sensitivities and detection limits better than those in usual PGA systems have been achieved. Boron and multielemental determination by a comparative standardization have been investigated, and accuracy, precision, and detection limits for the elements in various materials were evaluated. The system has been applied to the determination of B and multielements in samples of various fields such as medical, environmental, and geological sciences.

  4. Performance analysis of satellite-to-ground downlink coherent optical communications with spatial diversity over Gamma-Gamma atmospheric turbulence.

    PubMed

    Ma, Jing; Li, Kangning; Tan, Liying; Yu, Siyuan; Cao, Yubin

    2015-09-01

    The performances of satellite-to-ground downlink optical communications over Gamma-Gamma distributed atmospheric turbulence are studied for a coherent detection receiving system with spatial diversity. Maximum ratio combining (MRC) and selection combining (SC) techniques are considered as practical schemes to mitigate the atmospheric turbulence. Bit-error rate (BER) performances for binary phase-shift keying modulated coherent detection and outage probabilities are analyzed and compared for SC diversity using analytical results and for MRC diversity through an approximation method with different numbers of receiving aperture each with the same aperture area. To show the net diversity gain of a multiple aperture receiver system, BER performances and outage probabilities of MRC and SC multiple aperture receiver systems are compared with a single monolithic aperture with the same total aperture area (same total average incident optical power) for satellite-to-ground downlink optical communications. All the numerical results are verified by Monte-Carlo simulations. PMID:26368880

  5. Exact error rate analysis of free-space optical communications with spatial diversity over Gamma-Gamma atmospheric turbulence

    NASA Astrophysics Data System (ADS)

    Ma, Jing; Li, Kangning; Tan, Liying; Yu, Siyuan; Cao, Yubin

    2016-02-01

    The error rate performances and outage probabilities of free-space optical (FSO) communications with spatial diversity are studied for Gamma-Gamma turbulent environments. Equal gain combining (EGC) and selection combining (SC) diversity are considered as practical schemes to mitigate turbulence. The exact bit-error rate (BER) expression and outage probability are derived for direct detection EGC multiple aperture receiver system. BER performances and outage probabilities are analyzed and compared for different number of sub-apertures each having aperture area A with EGC and SC techniques. BER performances and outage probabilities of a single monolithic aperture and multiple aperture receiver system with the same total aperture area are compared under thermal-noise-limited and background-noise-limited conditions. It is shown that multiple aperture receiver system can greatly improve the system communication performances. And these analytical tools are useful in providing highly accurate error rate estimation for FSO communication systems.

  6. Performance analysis of satellite-to-ground downlink optical communications with spatial diversity over Gamma-Gamma atmospheric turbulence

    NASA Astrophysics Data System (ADS)

    Li, Kangning; Ma, Jing; Belmonte, Aniceto; Tan, Liying; Yu, Siyuan

    2015-12-01

    The performances of satellite-to-ground downlink optical communications over Gamma-Gamma distributed turbulence are studied for a multiple-aperture receiver system. Equal gain-combining (EGC) and selection-combining (SC) techniques are considered as practical schemes to mitigate the atmospheric turbulence under thermal-noise-limited conditions. Bit-error rate (BER) performances for on-off keying-modulated direct detection and outage probabilities are analyzed and compared for SC diversity receptions using analytical results and for EGC diversity receptions through an approximation method. To show the net diversity gain of a multiple-aperture receiver system, BER performances and outage probabilities of EGC and SC receiver systems are compared with a single monolithic-aperture receiver system with the same total aperture area (same average total incident optical power) for satellite-to-ground downlink optical communications. All the numerical results are also verified by Monte-Carlo simulations.

  7. Performance analysis of satellite-to-ground downlink coherent optical communications with spatial diversity over Gamma-Gamma atmospheric turbulence.

    PubMed

    Ma, Jing; Li, Kangning; Tan, Liying; Yu, Siyuan; Cao, Yubin

    2015-09-01

    The performances of satellite-to-ground downlink optical communications over Gamma-Gamma distributed atmospheric turbulence are studied for a coherent detection receiving system with spatial diversity. Maximum ratio combining (MRC) and selection combining (SC) techniques are considered as practical schemes to mitigate the atmospheric turbulence. Bit-error rate (BER) performances for binary phase-shift keying modulated coherent detection and outage probabilities are analyzed and compared for SC diversity using analytical results and for MRC diversity through an approximation method with different numbers of receiving aperture each with the same aperture area. To show the net diversity gain of a multiple aperture receiver system, BER performances and outage probabilities of MRC and SC multiple aperture receiver systems are compared with a single monolithic aperture with the same total aperture area (same total average incident optical power) for satellite-to-ground downlink optical communications. All the numerical results are verified by Monte-Carlo simulations.

  8. [A method for the analysis of overlapped peaks in the high performance liquid chromatogram based on spectrum analysis].

    PubMed

    Liu, Bao; Fan, Xiaoming; Huo, Shengnan; Zhou, Lili; Wang, Jun; Zhang, Hui; Hu, Mei; Zhu, Jianhua

    2011-12-01

    A method was established to analyse the overlapped chromatographic peaks based on the chromatographic-spectra data detected by the diode-array ultraviolet detector. In the method, the three-dimensional data were de-noised and normalized firstly; secondly the differences and clustering analysis of the spectra at different time points were calculated; then the purity of the whole chromatographic peak were analysed and the region were sought out in which the spectra of different time points were stable. The feature spectra were extracted from the spectrum-stable region as the basic foundation. The nonnegative least-square method was chosen to separate the overlapped peaks and get the flow curve which was based on the feature spectrum. The three-dimensional divided chromatographic-spectrum peak could be gained by the matrix operations of the feature spectra with the flow curve. The results displayed that this method could separate the overlapped peaks.

  9. Analysis of spectra from portable handheld gamma-ray spectrometry for terrain comparative assessment.

    PubMed

    Dias, Flávio; Lima, Marco; Sanjurjo-Sánchez, Jorge; Alves, Carlos

    2016-04-01

    Geological characteristics can have impacts on societal development by, e.g., geotechnical issues and radiological hazard levels. Due to urban sprawl, there is an increasing need for detailed geological assessment. In this work are analysed data from portable handheld gamma-ray spectra (K, eU and eTh) obtained in granitic and Silurian metaclastic outcrops as well as in an profile, roughly N-S, on soil covered terrains transecting a mapped contact between these rock types (the profile's northern extremity is at locations mapped as granite). Estimations from gamma-ray spectra were studied by univariate and multivariate analyses. K, eU and eTh values were higher on granite in relation to Silurian metaclastic rocks. The northern extremity of the profile showed clearly higher contents of eTh and this contrast was supported by univariate statistical tools (normality plot and Wilk-Shapiro test; boxplots). A ternary plot with the contribution of the elements to gamma-ray absorbed dose showed the separation of granite from Silurian metaclastic rocks with the former being nearer the eTh vertex. The points in the northern extremity of the profile are nearer the eTh vertex than the other points on the profile. These visual suggestions were supported by hierarchical cluster analysis, which was able to differentiate between granite and metaclastic outcrops and separate portions of the profile located on different terrains. Portable gamma-ray spectrometry showed, hence, the potential to distinguish granite and metaclastic terrains at a scale useful for engineering works. These results can also be useful for a first comparative zoning of radiological hazards (which are higher for granite). PMID:26867098

  10. Analysis of spectra from portable handheld gamma-ray spectrometry for terrain comparative assessment.

    PubMed

    Dias, Flávio; Lima, Marco; Sanjurjo-Sánchez, Jorge; Alves, Carlos

    2016-04-01

    Geological characteristics can have impacts on societal development by, e.g., geotechnical issues and radiological hazard levels. Due to urban sprawl, there is an increasing need for detailed geological assessment. In this work are analysed data from portable handheld gamma-ray spectra (K, eU and eTh) obtained in granitic and Silurian metaclastic outcrops as well as in an profile, roughly N-S, on soil covered terrains transecting a mapped contact between these rock types (the profile's northern extremity is at locations mapped as granite). Estimations from gamma-ray spectra were studied by univariate and multivariate analyses. K, eU and eTh values were higher on granite in relation to Silurian metaclastic rocks. The northern extremity of the profile showed clearly higher contents of eTh and this contrast was supported by univariate statistical tools (normality plot and Wilk-Shapiro test; boxplots). A ternary plot with the contribution of the elements to gamma-ray absorbed dose showed the separation of granite from Silurian metaclastic rocks with the former being nearer the eTh vertex. The points in the northern extremity of the profile are nearer the eTh vertex than the other points on the profile. These visual suggestions were supported by hierarchical cluster analysis, which was able to differentiate between granite and metaclastic outcrops and separate portions of the profile located on different terrains. Portable gamma-ray spectrometry showed, hence, the potential to distinguish granite and metaclastic terrains at a scale useful for engineering works. These results can also be useful for a first comparative zoning of radiological hazards (which are higher for granite).

  11. Europium-152 depth profile of a stone bridge pillar exposed to the Hiroshima atomic bomb: 152Eu activities for analysis of the neutron spectrum.

    PubMed

    Hasai, H; Iwatani, K; Shizuma, K; Hoshi, M; Yokoro, K; Sawada, S; Kosako, T; Morishima, H

    1987-09-01

    The 152Eu activity depth profile of a granite pillar of the Motoyasu bridge located 132 m from the Hiroshima atomic bomb hypocenter was assessed. The pillars each measured 82 cm in depth, 82 cm in width and 193 cm in height. One of the pillars was bored and 6.8-cm-diameter core samples were removed and cut into 2-cm-thick disks. Two gamma rays of 152Eu, 122 keV and 344 keV, in each disk were measured using a low background, gamma-ray spectrometer, and the activity distribution was determined as a function of depth in the granite. A concentration of stable Eu in the granite was determined by activation analysis. The specific radioactivity of 152Eu and 154Eu at the pillar surface was determined to have been 117 and 24 Bq per mg Eu, respectively, at the time of detonation. The value of 152Eu agrees within 20% of that calculated by Loewe. The depth profile of 152Eu in granite demonstrates a distinct difference from the estimates made only by thermal neutrons. Present data provide valuable information for the analysis of the neutron spectrum of the Hiroshima atomic bomb and its intensity.

  12. Sensitivity analysis of two-spectrum separation of surface and bulk components of minority carrier lifetimes

    NASA Astrophysics Data System (ADS)

    Brody, Jed; Rohatgi, Ajeet

    2002-06-01

    Performing quasi-steady-state lifetime measurements using two different illuminating spectra provides quantitative information about bulk lifetime ( τb) and surface recombination velocity ( S). This paper motivates the investigation of this relatively new method by demonstrating that the conventional method of iodine/methanol passivation for the extraction of τb, which is then used to calculate S for a dielectric, may fail for solar-grade materials such as string ribbon silicon. To facilitate the use of the two-spectrum method, first we introduce a novel empirical procedure for the determination of the constant of proportionality between the short-circuit current of the reference cell and the average generation rate ( Gav) in the test wafer. Then a sensitivity analysis is performed to show that the method of using a white light spectrum and an infrared spectrum to obtain information about τb and S also has serious limitations in certain cases: only a lower bound can be placed on τb for τb greater than about 10 μs, and only an upper bound can be placed on S for S less than about 1000 cm/s. Our analysis demonstrates that in order to use the two-spectrum method to specify τb and S within a factor of about 2-20 when experimental uncertainty is ±10%, the quality of both the bulk of the material and the surface passivation must be somewhat poor. Precision may be improved by reducing experimental uncertainty. To illustrate the requirement that bulk and surface recombination must be high in order to use the two-spectrum method with the greatest precision, the method was applied to nitride-passivated float zone and cast multicrystalline silicon wafers of different resistivity. Only an upper limit to S (165 cm/s) was inferred for the easily passivated float zone wafer, whereas both upper and lower limits to S were extracted for the less effectively passivated heat-exchanger method (HEM) multicrystalline wafers. The analysis yielded 1200< S<4200 cm/s for the 1.4 Ω cm

  13. Tensor based singular spectrum analysis for automatic scoring of sleep EEG.

    PubMed

    Kouchaki, Samaneh; Sanei, Saeid; Arbon, Emma L; Dijk, Derk-Jan

    2015-01-01

    A new supervised approach for decomposition of single channel signal mixtures is introduced in this paper. The performance of the traditional singular spectrum analysis algorithm is significantly improved by applying tensor decomposition instead of traditional singular value decomposition. As another contribution to this subspace analysis method, the inherent frequency diversity of the data has been effectively exploited to highlight the subspace of interest. As an important application, sleep electroencephalogram has been analyzed and the stages of sleep for the subjects in normal condition, with sleep restriction, and with sleep extension have been accurately estimated and compared with the results of sleep scoring by clinical experts.

  14. Classification of awake, REM, and NREM from EEG via singular spectrum analysis.

    PubMed

    Mohammadi, Sara Mahvash; Enshaeifar, Shirin; Ghavami, Mohammad; Sanei, Saeid

    2015-01-01

    In this study, a single-channel electroencephalography (EEG) analysis method has been proposed for automated 3-state-sleep classification to discriminate Awake, NREM (non-rapid eye movement) and REM (rapid eye movement). For this purpose, singular spectrum analysis (SSA) is applied to automatically extract four brain rhythms: delta, theta, alpha, and beta. These subbands are then used to generate the appropriate features for sleep classification using a multi class support vector machine (M-SVM). The proposed method provided 0.79 agreement between the manual and automatic scores.

  15. Determination of hydrogen in metals, semiconductors, and other materials by cold neutron prompt gamma-ray activation analysis

    SciTech Connect

    Paul, R.L.; Lindstrom, R.M.

    1998-12-31

    Cold neutron prompt gamma-ray activation analysis has proven useful for nondestructive measurement of trace hydrogen. The sample is irradiated in a beam of neutrons; the presence of hydrogen is confirmed by the emission of a 2223 keV gamma-ray. Detection limits for hydrogen are 3 mg/kg in quartz and 8 mg/kg in titanium. The authors have used the technique to measure hydrogen in titanium alloys, germanium, quartz, fullerenes and their derivatives, and other materials.

  16. Using the Autism-Spectrum Quotient to Measure Autistic Traits in Anorexia Nervosa: A Systematic Review and Meta-Analysis

    ERIC Educational Resources Information Center

    Westwood, Heather; Eisler, Ivan; Mandy, William; Leppanen, Jenni; Treasure, Janet; Tchanturia, Kate

    2016-01-01

    Interest in the link between Autism Spectrum Disorder (ASD) and Anorexia Nervosa (AN) has led to estimates of the prevalence of autistic traits in AN. This systematic review and meta-analysis assessed the use of the Autism-Spectrum Quotient (AQ) or abbreviated version (AQ-10) to examine whether patients with AN have elevated levels of autistic…

  17. Innovative technology-based interventions for autism spectrum disorders: a meta-analysis.

    PubMed

    Grynszpan, Ouriel; Weiss, Patrice L Tamar; Perez-Diaz, Fernando; Gal, Eynat

    2014-05-01

    This article reports the results of a meta-analysis of technology-based intervention studies for children with autism spectrum disorders. We conducted a systematic review of research that used a pre-post design to assess innovative technology interventions, including computer programs, virtual reality, and robotics. The selected studies provided interventions via a desktop computer, interactive DVD, shared active surface, and virtual reality. None employed robotics. The results provide evidence for the overall effectiveness of technology-based training. The overall mean effect size for posttests of controlled studies of children with autism spectrum disorders who received technology-based interventions was significantly different from zero and approached the medium magnitude, d = 0.47 (confidence interval: 0.08-0.86). The influence of age and IQ was not significant. Differences in training procedures are discussed in the light of the negative correlation that was found between the intervention durations and the studies' effect sizes. The results of this meta-analysis provide support for the continuing development, evaluation, and clinical usage of technology-based intervention for individuals with autism spectrum disorders.

  18. Chemometric analysis for extraction of individual fluorescence spectrum and lifetimes from a target mixture

    NASA Technical Reports Server (NTRS)

    Hallidy, William H. (Inventor); Chin, Robert C. (Inventor)

    1999-01-01

    The present invention is a system for chemometric analysis for the extraction of the individual component fluorescence spectra and fluorescence lifetimes from a target mixture. The present invention combines a processor with an apparatus for generating an excitation signal to transmit at a target mixture and an apparatus for detecting the emitted signal from the target mixture. The present invention extracts the individual fluorescence spectrum and fluorescence lifetime measurements from the frequency and wavelength data acquired from the emitted signal. The present invention uses an iterative solution that first requires the initialization of several decision variables and the initial approximation determinations of intermediate matrices. The iterative solution compares the decision variables for convergence to see if further approximation determinations are necessary. If the solution converges, the present invention then determines the reduced best fit error for the analysis of the individual fluorescence lifetime and the fluorescence spectrum before extracting the individual fluorescence lifetime and fluorescence spectrum from the emitted signal of the target mixture.

  19. In vivo Prompt Gamma Neutron Activation Analysis Facility for Total Body Nitrogen and Cd

    SciTech Connect

    Munive, Marco; Revilla, Angel; Solis, Jose L.

    2007-10-26

    A Prompt Gamma Neutron Activation Analysis (PGNAA) system has been designed and constructed to measure the total body nitrogen and Cd for in vivo studies. An aqueous solution of KNO{sub 3} was used as phantom for system calibration. The facility has been used to monitor total body nitrogen (TBN) of mice and found that is related to their diet. Some mice swallowed diluted water with Cl{sub 2}Cd, and the presence of Cd was detected in the animals. The minimum Cd concentration that the system can detect was 20 ppm.

  20. Association Between Antidepressants Use During Pregnancy and Autistic Spectrum Disorders: A Meta-analysis

    PubMed Central

    Rais, Alexandra

    2014-01-01

    Objective: Antidepressants have been reported in several studies in the literature to be associated with the development of autistic disorder symptoms in children exposed to them during the time of their mothers’ pregnancies. There have also been reports of neurodevelopment delays associated with exposure to antidepressants in the same conditions. Design: We searched the PUBMED, MEDLINE, PsycARTICLES, and ERIC for original articles published between January 1983 and May 2013 to identify studies on the association between autistic spectrum disorders (ASD) and neurodevelopment delays in children and exposure to antidepressants during pregnancy. Conclusion: At the end of our preliminary work, we retained only three articles that were pertinent to the purpose of our study. We extracted the available data in Excel files and then did a meta-analysis. The final results showed a positive association between the exposure to antidepressants in utero and autistic spectrum disorders. PMID:25152842

  1. Absorption spectrum and analysis of the ND 4 Schüler band

    NASA Astrophysics Data System (ADS)

    Alberti, F.; Huber, K. P.; Watson, J. K. G.

    1984-09-01

    A high-resolution absorption spectrum of the main Schüler band of ND 4, with heads at 6746 and 6749 Å ( ν00 = 14828 cm -1), has been obtained by the flash discharge method, using mixtures of ND 3 and D 2. The spectrum confirms and extends the recent observation of ND 4 absorption in laser frequency modulation spectroscopy by Hunziker and co-workers. The detailed rotational analysis establishes the electronic assignment as 3 p2F2 ← 3 s2A1, and results in molecular constants in moderate agreement with expectations based on ab initio calculations. The 30-μsec lifetime of the 3 s2A1 ground state of ND 4 is consistent with the 20-μsec lower limit estimated by Porter and co-workers on the basis of neutralized-ion-beam spectroscopy.

  2. Electromagnetic Spectrum Analysis and Its Influence on the Photoelectric Conversion Efficiency of Solar Cells.

    PubMed

    Hu, Kexiang; Ding, Enjie; Wangyang, Peihua; Wang, Qingkang

    2016-06-01

    The electromagnetic spectrum and the photoelectric conversion efficiency of the silicon hexagonal nanoconical hole (SiHNH) arrays based solar cells is systematically analyzed according to Rigorous Coupled Wave Analysis (RCWA) and Modal Transmission Line (MTL) theory. An ultimate efficiency of the optimized SiHNH arrays based solar cell is up to 31.92% in consideration of the absorption spectrum, 4.52% higher than that of silicon hexagonal nanoconical frustum (SiHNF) arrays. The absorption enhancement of the SiHNH arrays is due to its lower reflectance and more supported guided-mode resonances, and the enhanced ultimate efficiency is insensitive to bottom diameter (D(bot)) of nanoconical hole and the incident angle. The result provides an additional guideline for the nanostructure surface texturing fabrication design for photovoltaic applications.

  3. SPECTRUM analysis of multispectral imagery in conjunction with wavelet/KLT data compression

    SciTech Connect

    Bradley, J.N.; Brislawn, C.M.

    1993-12-01

    The data analysis program, SPECTRUM, is used for fusion, visualization, and classification of multi-spectral imagery. The raw data used in this study is Landsat Thematic Mapper (TM) 7-channel imagery, with 8 bits of dynamic range per channel. To facilitate data transmission and storage, a compression algorithm is proposed based on spatial wavelet transform coding and KLT decomposition of interchannel spectral vectors, followed by adaptive optimal multiband scalar quantization. The performance of SPECTRUM clustering and visualization is evaluated on compressed multispectral data. 8-bit visualizations of 56-bit data show little visible distortion at 50:1 compression and graceful degradation at higher compression ratios. Two TM images were processed in this experiment: a 1024 x 1024-pixel scene of the region surrounding the Chernobyl power plant, taken a few months before the reactor malfunction, and a 2048 x 2048 image of Moscow and surrounding countryside.

  4. Analysis of the free ion spectrum of Er3+(Er IV)

    NASA Astrophysics Data System (ADS)

    Meftah, A.; Ait Mammar, S.; Wyart, J.-F.; Tchang-Brillet, W.-Ü. L.; Champion, N.; Blaess, C.; Deghiche, D.; Lamrous, O.

    2016-08-01

    The vacuum spark spectrum of erbium is observed in the wavelength region 705–2460 Å where transitions between the low-lying configurations 4{f}11, 4{f}105d, 4{f}106s and 4{f}106p take place. Predictions of energy levels and electric dipole transition probabilities by means of the Cowan codes served for a complete revised analysis of the spectrum. The identification of 591 spectral lines as transitions mostly between low levels of these four configurations led to the determination of 120 energy levels. Radial parameters obtained in least-squares fits of both parities are compared with ab initio Hartree–Fock integrals including relativistic corrections. The mean error of the fits are respectively 41 cm‑1 for 38 known levels of the odd parity configurations 4{f}11 + 4{f}106p and 49 cm‑1 for 82 known levels of the even configurations 4{f}105d + 4{f}106s.

  5. Electromagnetic Spectrum Analysis and Its Influence on the Photoelectric Conversion Efficiency of Solar Cells.

    PubMed

    Hu, Kexiang; Ding, Enjie; Wangyang, Peihua; Wang, Qingkang

    2016-06-01

    The electromagnetic spectrum and the photoelectric conversion efficiency of the silicon hexagonal nanoconical hole (SiHNH) arrays based solar cells is systematically analyzed according to Rigorous Coupled Wave Analysis (RCWA) and Modal Transmission Line (MTL) theory. An ultimate efficiency of the optimized SiHNH arrays based solar cell is up to 31.92% in consideration of the absorption spectrum, 4.52% higher than that of silicon hexagonal nanoconical frustum (SiHNF) arrays. The absorption enhancement of the SiHNH arrays is due to its lower reflectance and more supported guided-mode resonances, and the enhanced ultimate efficiency is insensitive to bottom diameter (D(bot)) of nanoconical hole and the incident angle. The result provides an additional guideline for the nanostructure surface texturing fabrication design for photovoltaic applications. PMID:27427668

  6. Gamma-ray spectrum of the radioactive dust produced by the super-hydrogen bomb test explosion on March 1, 1954

    NASA Astrophysics Data System (ADS)

    Shimizu, Sakae

    1987-03-01

    The super-hydrogen bomb test explosion, the so-called Bravo test of a fission-fusion-fission bomb, was carried out on Bikini Atoll in the mid-Pacific on March 1, 1954. Twenty-three Japanese fishermen on board a fishing boat about 90 miles north-east of the test site were attacked unexpectedly by the fallout, radioactive fine debris of coral reef. Within several months after the accident by radiochemical analysis about 20 different nuclides of fission products and, in addition, a considerable amount of 235U were discovered from the fallout. As we have been preserving a minute amount of the original fallout dust collected on board the fishing boat 31 years ago, measurements of γ rays from it have recently been used to find some active nuclides, if still existing. In the γ-ray spectrum observed there exist evident peaks of γ and X-rays from 241Am, 155Eu, 137Cs, and 60Co. Absolute intensities of these four nuclides, still remaining 31 years after the explosion of the bomb, have been estimated. Some discussion on our finding is presented.

  7. Analysis of Gamma-Ray Data from Solar Flares in Cycles 21 and 22

    NASA Technical Reports Server (NTRS)

    Vestrand, W. Thomas

    1998-01-01

    One of our primary accomplishments under grant NAGW-35381 was the systematic derivation and compilation, for the first time, of physical parameters for all gamma-ray flares detected by the SMM GRS during its ten year lifetime. The flare parameters derived from the gamma-ray spectra include: bremsstrahlung fluence and best-fit power-law parameters, narrow nuclear line fluence, positron annihilation line fluence, neutron capture line fluence, and an indication of whether or not greater than 10 MeV emissions were present. We combined this compilation of flare parameters with our plots of counting rate time histories and flare spectra to construct an atlas of gamma-ray flare characteristics. The atlas time histories display four energy bands: 56-199 kev, 298526 keV, 4-8 MeV, and 10-25 MeV. These energy bands respectively measure nonrelativistic bremsstrahlung, trans-relativistic bremsstrahlung, nuclear de-excitation, and ultra-relativistic bremsstrahlung. The atlas spectra show the integrated high-energy spectra measured for all GRS flares and dissects them into electron bremsstrahlung, positron annihilation and nuclear emission components. The atlas has been accepted for publication in the Astrophysical Journal Supplements and is currently in press. The atlas materials were also supplied to the Solar Data Analysis Center at Goddard Space Flight Center and were made available through a web site at the University of New Hampshire. Since a uniform methodology was adopted for deriving the flare parameters, this atlas will be very useful for future statistical and correlative studies of solar flares-three independent groups are presently using it to correlate interplanetary energetic particle measurements with our gamma-ray measurements. A better model for the response of the GRS instrument to high energy radiation was also developed. A refined response model was needed because the old model was not adequate for predicting the first and second escape peaks associated with

  8. Measurement of the keV-neutron capture cross section and capture gamma-ray spectrum of isotopes around N=82 region

    SciTech Connect

    Katabuchi, Tatsuya; Igashira, Masayuki

    2012-11-12

    The keV-neutron capture cross section and capture {gamma}-ray spectra of nuclides with a neutron magic number N= 82, {sup 139}La and {sup 142}Nd, were newly measured by the time-of-flight method. Capture {gamma}-rays were detected with an anti-Compton NaI(T1) spectrometer, and the pulse-height weighting technique was applied to derive the neutron capture cross section. The results were provided with our previous measurements of other nuclides around N= 82, {sup 140}Ce, {sup 141}Pr, {sup 143}Nd and {sup 145}Nd.

  9. Fermi-LAT detection of hard spectrum and enhanced gamma-ray emission from the BL Lac object PKS 1717+177

    NASA Astrophysics Data System (ADS)

    Ciprini, Stefano

    2015-12-01

    The Large Area Telescope (LAT), one of two instruments on the Fermi Gamma-ray Space Telescope, has observed a gamma-ray flare from a source positionally consistent with the BL Lac object PKS 1717+177 (also known as S3 1717+17, OT 129, and 3FGL J1719.2+1744, Acero et al. 2015, ApJS, 218, 23), with radio coordinates (J2000.0), R.A.: 259.804368 deg, Dec.: 17.751788 deg (Johnston et al. 1995, AJ, 110, 880).

  10. Raman and AFM study of gamma irradiated plastic bottle sheets

    NASA Astrophysics Data System (ADS)

    Ali, Yasir; Kumar, Vijay; Sonkawade, R. G.; Dhaliwal, A. S.

    2013-02-01

    In this investigation, the effects of gamma irradiation on the structural properties of plastic bottle sheet are studied. The Plastic sheets were exposed with 1.25MeV 60Co gamma rays source at various dose levels within the range from 0-670 kGy. The induced modifications were followed by micro-Raman and atomic force microscopy (AFM). The Raman spectrum shows the decrease in Raman intensity and formation of unsaturated bonds with an increase in the gamma dose. AFM image displays rough surface morphology after irradiation. The detailed Raman analysis of plastic bottle sheets is presented here, and the results are correlated with the AFM observations.

  11. Raman and AFM study of gamma irradiated plastic bottle sheets

    SciTech Connect

    Ali, Yasir; Kumar, Vijay; Dhaliwal, A. S.; Sonkawade, R. G.

    2013-02-05

    In this investigation, the effects of gamma irradiation on the structural properties of plastic bottle sheet are studied. The Plastic sheets were exposed with 1.25MeV {sup 60}Co gamma rays source at various dose levels within the range from 0-670 kGy. The induced modifications were followed by micro-Raman and atomic force microscopy (AFM). The Raman spectrum shows the decrease in Raman intensity and formation of unsaturated bonds with an increase in the gamma dose. AFM image displays rough surface morphology after irradiation. The detailed Raman analysis of plastic bottle sheets is presented here, and the results are correlated with the AFM observations.

  12. AlphaSpectrum ASPECT analysis code for background correction & peak integration

    2005-04-13

    The ASPECT code provides a means for rapid analysis of energy-resolved spectra obtained by multi-channel pulse-height analysis (MCA) during (or after) counting of alpha-emissions from a filter air sample (or other suitably prepared sample) utilizing a solid-state detector, or other detector having sufficient energy resolution indiviual radioisotope peaks indentified in a spectrum are fitted using a peak shape algorithm by non-linear least-square fitting procedures that minimize Chi-square differences between the data and a fitted peakmore » function. The code accomplishes the identification of all significant peaks present in the spectrum with automatic recalibration to the 7.68 Po-214 alpha peak from the Radon-222 decay chain, the subtraction of all radon progeny interference overlaps with lower energy peaks in the energy range of Pu-238, Am-241, Pu-239, and U-234/Th-232, and the integration of the counts in any peak identified for these transuranic radionuclides. The output is therefore in the form of isotope specific net transuranic CPM, DPM or concentration, available in near real-time during air sampling. In this "copyright" version, the assumption is made that the alpha spectra to be analyzed have been stored by unique name in sequential form: "FileName(i)", where "FileName" can be any name and i is the index number of the file saved (e.g., i = 1,2, ..., n). this format is one automatically generated by the alpha Environmental Continuous Air Monitor (ECAM), developed by Los Alamos National Laboratory, and manufactured by Canberra Industries, a Laboratory Industrial Partner for this technology. It is assumed in this version of the code that the alpha spectrum data are stored in a 256 channel spectrum, although a larger num ber of channels could be easily accommodated by small code changes. The ECAM data output format is RADNET compliant (an inidustry standard developed at Los Alamos), and include, in addition to a 256-channel alpha spectrum, data on the

  13. The Prompt Gamma Neutron Activation Analysis Facility at ICN-Pitesti

    SciTech Connect

    Barbos, D.; Paunoiu, C.; Mladin, M.; Cosma, C.

    2008-08-14

    PGNAA is a very widely applicable technique for determining the presence and amount of many elements simultaneously in samples ranging in size from micrograms to many grams. PGNAA is characterized by its capability for nondestructive multi-elemental analysis and its ability to analyse elements that cannot be determined by INAA. By means of this PGNAA method we are able to increase the performance of INAA method. A facility has been developed at Institute for Nuclear Research-Pitesti so that the unique features of prompt gamma-ray neutron activation analysis can be used to measure trace and major elements in samples. The facility is linked at the radial neutron beam tube at ACPR-TRIGA reactor. During the PGNAA-facility is in use the ACPR reactor will be operated in steady-state mode at 250 KW maximum power. The facility consists of a radial beam-port, external sample position with shielding, and induced prompt gamma-ray counting system.Thermal neutron flux with energy lower than cadmium cut-off at the sample position was measured using thin gold foil is: {phi}{sub scd} = 1.10{sup 6} n/cm{sup 2}/s with a cadmium ratio of:80.The gamma-ray detection system consist of an HpGe detector of 16% efficiency (detector model GC1518) with 1.85 keV resolution capability. The HpGe is mounted with its axis at 90 deg. with respect to the incident neutron beam at distance about 200mm from the sample position. To establish the performance capabilities of the facility, irradiation of pure element or sample compound standards were performed to identify the gama-ray energies from each element and their count rates.

  14. GRABGAM: A Gamma Analysis Code for Ultra-Low-Level HPGe SPECTRA

    SciTech Connect

    Winn, W.G.

    1999-07-28

    The GRABGAM code has been developed for analysis of ultra-low-level HPGe gamma spectra. The code employs three different size filters for the peak search, where the largest filter provides best sensitivity for identifying low-level peaks and the smallest filter has the best resolution for distinguishing peaks within a multiplet. GRABGAM basically generates an integral probability F-function for each singlet or multiplet peak analysis, bypassing the usual peak fitting analysis for a differential f-function probability model. Because F is defined by the peak data, statistical limitations for peak fitting are avoided; however, the F-function does provide generic values for peak centroid, full width at half maximum, and tail that are consistent with a Gaussian formalism. GRABGAM has successfully analyzed over 10,000 customer samples, and it interfaces with a variety of supplementary codes for deriving detector efficiencies, backgrounds, and quality checks.

  15. Bayesian Statistical Analysis Applied to NAA Data for Neutron Flux Spectrum Determination

    NASA Astrophysics Data System (ADS)

    Chiesa, D.; Previtali, E.; Sisti, M.

    2014-04-01

    In this paper, we present a statistical method, based on Bayesian statistics, to evaluate the neutron flux spectrum from the activation data of different isotopes. The experimental data were acquired during a neutron activation analysis (NAA) experiment [A. Borio di Tigliole et al., Absolute flux measurement by NAA at the Pavia University TRIGA Mark II reactor facilities, ENC 2012 - Transactions Research Reactors, ISBN 978-92-95064-14-0, 22 (2012)] performed at the TRIGA Mark II reactor of Pavia University (Italy). In order to evaluate the neutron flux spectrum, subdivided in energy groups, we must solve a system of linear equations containing the grouped cross sections and the activation rate data. We solve this problem with Bayesian statistical analysis, including the uncertainties of the coefficients and the a priori information about the neutron flux. A program for the analysis of Bayesian hierarchical models, based on Markov Chain Monte Carlo (MCMC) simulations, is used to define the problem statistical model and solve it. The energy group fluxes and their uncertainties are then determined with great accuracy and the correlations between the groups are analyzed. Finally, the dependence of the results on the prior distribution choice and on the group cross section data is investigated to confirm the reliability of the analysis.

  16. Database of prompt gamma rays from slow neutron capture forelemental analysis

    SciTech Connect

    Firestone, R.B.; Choi, H.D.; Lindstrom, R.M.; Molnar, G.L.; Mughabghab, S.F.; Paviotti-Corcuera, R.; Revay, Zs; Trkov, A.; Zhou,C.M.; Zerkin, V.

    2004-12-31

    The increasing importance of Prompt Gamma-ray ActivationAnalysis (PGAA) in a broad range of applications is evident, and has beenemphasized at many meetings related to this topic (e.g., TechnicalConsultants' Meeting, Use of neutron beams for low- andmedium-fluxresearch reactors: radiography and materialscharacterizations, IAEA Vienna, 4-7 May 1993, IAEA-TECDOC-837, 1993).Furthermore, an Advisory Group Meeting (AGM) for the Coordination of theNuclear Structure and Decay Data Evaluators Network has stated that thereis a need for a complete and consistent library of cold- and thermalneutron capture gammaray and cross-section data (AGM held at Budapest,14-18 October 1996, INDC(NDS)-363); this AGM also recommended theorganization of an IAEA CRP on the subject. The International NuclearData Committee (INDC) is the primary advisory body to the IAEA NuclearData Section on their nuclear data programmes. At a biennial meeting in1997, the INDC strongly recommended that the Nuclear Data Section supportnew measurements andupdate the database on Neutron-induced PromptGamma-ray Activation Analysis (21st INDC meeting, INDC/P(97)-20). As aconsequence of the various recommendations, a CRP on "Development of aDatabase for Prompt Gamma-ray Neutron Activation Analysis (PGAA)" wasinitiated in 1999. Prior to this project, several consultants had definedthe scope, objectives and tasks, as approved subsequently by the IAEA.Each CRP participant assumed responsibility for the execution of specifictasks. The results of their and other research work were discussed andapproved by the participants in research co-ordination meetings (seeSummary reports: INDC(NDS)-411, 2000; INDC(NDS)-424, 2001; andINDC(NDS)-443, 200). PGAA is a non-destructive radioanalytical method,capable of rapid or simultaneous "in-situ" multi-element analyses acrossthe entire Periodic Table, from hydrogen to uranium. However, inaccurateand incomplete data were a significant hindrance in the qualitative andquantitative

  17. The measurement and interpretation of the cosmic gamma-ray spectrum between 0.3 and 27 MeV as obtained during the Apollo mission

    NASA Technical Reports Server (NTRS)

    Peterson, L. E.; Trombka, J. I.; Metzger, A. E.; Arnold, J. R.; Matteson, J. I.; Reedy, R. C.

    1973-01-01

    The cosmic gamma ray background spectra measured by Apollo 15 between 0.3 and 27 MeV during transearth orbit are examined. Both discrete line spectra and diffuse sources were measured. Data are included on energy loss spectra, equivalent photon spectra, spallation corrections, and cosmic photon spectra.

  18. PINS Spectrum Identification Guide

    SciTech Connect

    A.J. Caffrey

    2012-03-01

    The Portable Isotopic Neutron Spectroscopy—PINS, for short—system identifies the chemicals inside munitions and containers without opening them, a decided safety advantage if the fill chemical is a hazardous substance like a chemical warfare agent or an explosive. The PINS Spectrum Identification Guide is intended as a reference for technical professionals responsible for the interpretation of PINS gamma-ray spectra. The guide is divided into two parts. The three chapters that constitute Part I cover the science and technology of PINS. Neutron activation analysis is the focus of Chapter 1. Chapter 2 explores PINS hardware, software, and related operational issues. Gamma-ray spectral analysis basics are introduced in Chapter 3. The six chapters of Part II cover the identification of PINS spectra in detail. Like the PINS decision tree logic, these chapters are organized by chemical element: phosphorus-based chemicals, chlorine-based chemicals, etc. These descriptions of hazardous, toxic, and/or explosive chemicals conclude with a chapter on the identification of the inert chemicals, e.g. sand, used to fill practice munitions.

  19. Further Analysis of the Laboratory Rotational Spectrum of CH_3NCO

    NASA Astrophysics Data System (ADS)

    Kisiel, Zbigniew; Kolesniková, Lucie; Alonso, E. R.; Alonso, José L.; Winnewisser, Manfred; De Lucia, Frank C.; Medvedev, Ivan; Tercero, Belén; Cernicharo, Jose; Guillemin, J.-C.

    2016-06-01

    Identification by the Rosetta mission that CH_3NCO is among the more plentiful molecules on the surface of the comet Churyumov-Gerasimenko stimulated rapid detection of this molecule in the interstellar medium. In particular, we have been successful in detecting almost 400 lines of CH_3NCO in Orion^b by extending the Koput cm-wave assignment to frequencies relevant to mm-wave radio-telescopes through measurement of the complete laboratory spectrum up to 363 GHz. Presently, we describe further progress in understanding the laboratory rotational spectrum of CH_3NCO. Assignment has been extended to transitions with K>3 by analysis of Stark and hyperfine patterns of the corresponding lowest-J transitions. Broadband spectra of synthezised pure 13CH_3NCO and CH_3N13CO isotopic species have also been recorded and assigned. Furthermore, the progress in fitting this very low barrier and highly perturbed internal rotation spectrum is described. D.T.Halfen, V.V.Ilyushin, L.Ziurys, ApJ 812, L5 (1915) J.Cernicharo, Z.Kisiel, B.Tercero, et al., A&A 587, L4 (2016) J.Koput, J. Mol. Spectrosc. 115, 131 (1986) Z.Kisiel et al., 65th ISMS, Columbus, Ohio, RC-13 (2010); 70th ISMS, Champaign-Urbana, Illinois, TG-08 (2015)

  20. Monte Carlo model for neutron capture prompt gamma-ray analysis of coal in transmission geometry

    SciTech Connect

    Yuan, R.Y.

    1984-01-01

    In order to relate the detector response to the elemental concentration, a great number of elaborate experimental standards are needed. It is tedious and curbs, among other factors, the wider use of the neutron capture prompt gamma-ray analysis (NCPGRA). A Monte Carlo model therefore has been developed to predict the photopeak detector response at all elemental concentrations of interest in the host matrix simultaneously, and an experimental system which simulates the on-line analysis of coal on a conveyor belt has been built to test this model and increase the extent of its readiness for industrial application. Variance reduction techniques, including an expected value technique followed by Russian Roulette, are used extensively to reduce computation effort. Each of the various shielding components of the analyzer is considered with respect to both neutron transport and prompt gamma-ray attenuation. Further, the free gas model is employed to simulate thermal neutron interaction. Results of this Monte Carlo model are generally in good agreement with photopeak detector responses on those major and minor elements measurable by NCPGRA in coal, and the agreement is excellent on the variation in detector response with elemental concentration for sulfur and titanium. Therefore, it gives high confidence in the validity of the Monte Carlo model. The model is thus expected to be generally useful for calibrating NCPGRA analyzers in transmission geometry.

  1. [Studies on all-spectrum analysis for X-ray diffraction of Chinese herbal medicine calculus bovis].

    PubMed

    Lu, Y; Zheng, Q; Wu, N; Zhou, J; Bao, T

    1997-10-01

    Investigation on famouse Chinese herbal medicine-Niu huang (calculus bovis) was carried out by all-spectrum X-ray diffraction analysis. Diffraction spectrums, as well as the specific symboling peaks of calculus bovis, artificial bezoar, bile ductstone, human gallstone and hog gallstone, were recognized. The error distribution curves of d-delta d for specific symboling peaks was also obtained by calculation under diffrent testing conditions, by which we identified successfully three samples provided by a pharmaceutical factory. This article shows that all-spectrum X-ray diffraction analysis can be used to identify Chinese traditional crude drug, and provides for morphological and microscopical study.

  2. [Infrared Spectrum Analysis of Propolis and Tree Gum Collected from Different Areas].

    PubMed

    Luo, Huo-lin; Liu, Xing-xing; Gong, Shang-ji; Guo, Xia-li; Luo, Li-ping

    2015-11-01

    Propolis possesses functions of antibacterial, antiviral, anticancer, and liver protection, and is known as the "purple gold", however, the phenomenon which making and selling of counterfeit are growing in intensity. In order to establish a authenticity and quality of propolis evaluation model, in this paper, forty-one Chinese propolis, one proplis from United States and two tree gums were used for experimental materials. The infrared spectrum collection was performed by Fourier transform infrared spectrometer, and principal component analysis (PCA) was used for data analysis. The result showed that, the intrared spectrum of propolis and tree gum were significantly different. The propolis characteristic peak only appeared in 2500-3500 and 400-1800 cm⁻¹. All propolis had two frequency region of characteristic peaks, 2849.08-2848.53 and 2917.74- 2916.76 cm⁻¹, but tree gum did not have characteristic peak in this region. The characteristic peaks of gum were in 1150-1300 and 1550-1650 cm⁻¹. Differences in these aspects can be used to distinguish propolis and gum, and can be used to identify true and false propolis. We use Qinghai propolis as a standard sample, in 42 samples, the matching degree of other propolis is > 80%. In addition, the result of PCA shows that tree gum and the propolis from different climate zone, or with different colors could be distinguished well. This paper firstly performed analysis on different propolis and gum by infrared spectrum, and a new method, for authenticity and quality of propolis identification, could be developed.

  3. [Infrared Spectrum Analysis of Propolis and Tree Gum Collected from Different Areas].

    PubMed

    Luo, Huo-lin; Liu, Xing-xing; Gong, Shang-ji; Guo, Xia-li; Luo, Li-ping

    2015-11-01

    Propolis possesses functions of antibacterial, antiviral, anticancer, and liver protection, and is known as the "purple gold", however, the phenomenon which making and selling of counterfeit are growing in intensity. In order to establish a authenticity and quality of propolis evaluation model, in this paper, forty-one Chinese propolis, one proplis from United States and two tree gums were used for experimental materials. The infrared spectrum collection was performed by Fourier transform infrared spectrometer, and principal component analysis (PCA) was used for data analysis. The result showed that, the intrared spectrum of propolis and tree gum were significantly different. The propolis characteristic peak only appeared in 2500-3500 and 400-1800 cm⁻¹. All propolis had two frequency region of characteristic peaks, 2849.08-2848.53 and 2917.74- 2916.76 cm⁻¹, but tree gum did not have characteristic peak in this region. The characteristic peaks of gum were in 1150-1300 and 1550-1650 cm⁻¹. Differences in these aspects can be used to distinguish propolis and gum, and can be used to identify true and false propolis. We use Qinghai propolis as a standard sample, in 42 samples, the matching degree of other propolis is > 80%. In addition, the result of PCA shows that tree gum and the propolis from different climate zone, or with different colors could be distinguished well. This paper firstly performed analysis on different propolis and gum by infrared spectrum, and a new method, for authenticity and quality of propolis identification, could be developed. PMID:26978908

  4. Semi-automated structural analysis of high resolution magnetic and gamma-ray spectrometry airborne surveys

    NASA Astrophysics Data System (ADS)

    Debeglia, N.; Martelet, G.; Perrin, J.; Truffert, C.; Ledru, P.; Tourlière, B.

    2005-08-01

    A user-controlled procedure was implemented for the structural analysis of geophysical maps. Local edge segments are first extracted using a suitable edge detector function, then linked into straight discontinuities and, finally, organised in complex boundary lines best delineating geophysical features. Final boundary lines may be attributed by a geologist to lithological contacts and/or structural geological features. Tests of some edge detectors, (i) horizontal gradient magnitude (HGM), (ii) various orders of the analytic signal ( An), reduced to the pole or not, (iii) enhanced horizontal derivative (EHD), (iv) composite analytic signal (CAS), were performed on synthetic magnetic data (with and without noise). As a result of these comparisons, the horizontal gradient appears to remain the best operator for the analysis of magnetic data. Computation of gradients in the frequency domain, including filtering and upward continuation of noisy data, is well-suited to the extraction of magnetic gradients associated to deep sources, while space-domain smoothing and differentiation techniques is generally preferable in the case of shallow magnetic sources, or for gamma-ray spectrometry analysis. Algorithms for edge extraction, segment linking, and line following can be controlled by choosing adequate edge detector and processing parameters which allows adaptation to a desired scale of interpretation. Tests on synthetic and real case data demonstrate the adaptability of the procedure and its ability to produce basic layer for multi-data analysis. The method was applied to the interpretation of high-resolution airborne magnetic and gamma-ray spectrometry data collected in northern Namibia. It allowed the delineation of dyke networks concealed by superficial weathering and demonstrated the presence of lithological variations in alluvial flows. The output from the structural analysis procedure are compatible with standard GIS softwares and enable the geologist to (i) compare

  5. Timing and Fermi LAT Analysis of Four Millisecond Pulsars Discovered in Parkes Radio Searches of Gamma-ray Sources

    NASA Astrophysics Data System (ADS)

    Ray, Paul S.; Ransom, Scott M.; Camilo, Fernando M.; Kerr, Matthew; Reynolds, John; Sarkissian, John; Freire, Paulo; Thankful Cromartie, H.; Barr, Ewan D.

    2016-01-01

    We present phase-connected timing solutions for four binary millisecond pulsars discovered in searches of Fermi LAT gamma-ray sources using the Parkes radio telescope. Follow-up timing observations of PSRs J0955-6150, J1012-4235, J1036-8317, and J1946-5403 have yielded timing models with precise orbital and astrometric parameters. For each pulsar, we also did a gamma-ray spectral analysis using LAT Pass 8 data and generated photon probabilities for use in a weighted H-test pulsation test. In all 4 cases, we detect significant gamma-ray pulsations, confirming the identification with the gamma-ray source originally targeted in the discovery observations. We describe the results of the pulse timing and gamma-ray spectral and timing analysis and the characteristics of each of the systems. The Fermi-LAT Collaboration acknowledges support for LAT development, operation and data analysis from NASA and DOE (United States), CEA/Irfu and IN2P3/CNRS (France), ASI and INFN (Italy), MEXT, KEK, and JAXA (Japan), and the K.A. Wallenberg Foundation, the Swedish Research Council and the National Space Board (Sweden). Science analysis support in the operations phase from INAF (Italy) and CNES (France) is also gratefully acknowledged. NRL participation was funded by NASA.

  6. Application of an ensemble technique based on singular spectrum analysis to daily rainfall forecasting.

    PubMed

    Baratta, Daniela; Cicioni, Giovambattista; Masulli, Francesco; Studer, Léonard

    2003-01-01

    In previous work, we have proposed a constructive methodology for temporal data learning supported by results and prescriptions related to the embedding theorem, and using the singular spectrum analysis both in order to reduce the effects of the possible discontinuity of the signal and to implement an efficient ensemble method. In this paper we present new results concerning the application of this approach to the forecasting of the individual rain-fall intensities series collected by 135 stations distributed in the Tiber basin. The average RMS error of the obtained forecasting is less than 3mm of rain. PMID:12672433

  7. Piping benchmark problems. Volume 1. Dynamic analysis uniform support motion response spectrum method

    SciTech Connect

    Bezler, P.; Hartzman, M.; Reich, M.

    1980-08-01

    A set of benchmark problems and solutions have been developed for verifying the adequacy of computer programs used for dynamic analysis and design of nuclear piping systems by the Response Spectrum Method. The problems range from simple to complex configurations which are assumed to experience linear elastic behavior. The dynamic loading is represented by uniform support motion, assumed to be induced by seismic excitation in three spatial directions. The solutions consist of frequencies, participation factors, nodal displacement components and internal force and moment components. Solutions to associated anchor point motion static problems are not included.

  8. Sensitivity Analysis Applied to Atomic Data Used for X-ray Spectrum Synthesis

    NASA Technical Reports Server (NTRS)

    Kallman, T.

    2006-01-01

    A great deal of work has been devoted to the accumulation of accurate quantities describing atomic processes for use in analysis of astrophysical spectra. But in many situations of interest the interpretation of a quantity which is observed, such as a line flux, depends on the results of a modeling- or spectrum synthesis code. The results of such a code depends in turn on many atomic rates or cross sections, and the sensitivity of the observable quantity on the various rates and cross sections may be non-linear and if so cannot easily be derived analytically. This talk describes simple numerical experiments designed to examine some of these issues.

  9. Analysis of urinary stone based on a spectrum absorption FTIR-ATR

    NASA Astrophysics Data System (ADS)

    Asyana, V.; Haryanto, F.; Fitri, L. A.; Ridwan, T.; Anwary, F.; Soekersi, H.

    2016-03-01

    This research analysed the urinary stone by measuring samples using Fourier transform infrared-attenuated total reflection spectroscopy and black box analysis. The main objective of this study is to find kinds of urinary stone and determine a total spectrum, which is a simple model of the chemical and mineral composition urinary stone through black box analysis using convolution method. The measurements result showed that kinds of urinary stone were pure calcium oxalate monohydrate, ion amino acid calcium oxalate monohydrate, a mixture of calcium oxalate monohydrate with calcium phosphate, a mixture of ion amino acid calcium oxalate monohydrate and calcium phosphate,pure uric acid, ion amino acid uric acid, and a mixture of calcium oxalate monohydrate with ion amino acid uric acid. The results of analysis of black box showed characteristics as the most accurate and precise to confirm the type of urinary stones based on theregion absorption peak on a graph, the results of the convolution, and the shape of the total spectrum on each urinary stones.

  10. Fine-Grain Feature Extraction from Malware's Scan Behavior Based on Spectrum Analysis

    NASA Astrophysics Data System (ADS)

    Eto, Masashi; Sonoda, Kotaro; Inoue, Daisuke; Yoshioka, Katsunari; Nakao, Koji

    Network monitoring systems that detect and analyze malicious activities as well as respond against them, are becoming increasingly important. As malwares, such as worms, viruses, and bots, can inflict significant damages on both infrastructure and end user, technologies for identifying such propagating malwares are in great demand. In the large-scale darknet monitoring operation, we can see that malwares have various kinds of scan patterns that involves choosing destination IP addresses. Since many of those oscillations seemed to have a natural periodicity, as if they were signal waveforms, we considered to apply a spectrum analysis methodology so as to extract a feature of malware. With a focus on such scan patterns, this paper proposes a novel concept of malware feature extraction and a distinct analysis method named “SPectrum Analysis for Distinction and Extraction of malware features(SPADE)”. Through several evaluations using real scan traffic, we show that SPADE has the significant advantage of recognizing the similarities and dissimilarities between the same and different types of malwares.

  11. An analysis of the Kalman filter in the Gamma Ray Observatory (GRO) onboard attitude determination subsystem

    NASA Technical Reports Server (NTRS)

    Snow, Frank; Harman, Richard; Garrick, Joseph

    1988-01-01

    The Gamma Ray Observatory (GRO) spacecraft needs a highly accurate attitude knowledge to achieve its mission objectives. Utilizing the fixed-head star trackers (FHSTs) for observations and gyroscopes for attitude propagation, the discrete Kalman Filter processes the attitude data to obtain an onboard accuracy of 86 arc seconds (3 sigma). A combination of linear analysis and simulations using the GRO Software Simulator (GROSS) are employed to investigate the Kalman filter for stability and the effects of corrupted observations (misalignment, noise), incomplete dynamic modeling, and nonlinear errors on Kalman filter. In the simulations, on-board attitude is compared with true attitude, the sensitivity of attitude error to model errors is graphed, and a statistical analysis is performed on the residuals of the Kalman Filter. In this paper, the modeling and sensor errors that degrade the Kalman filter solution beyond mission requirements are studied, and methods are offered to identify the source of these errors.

  12. Analysis of Energy Spectrum with Low Photon Counts via Bayesian Posterior Simulation

    NASA Astrophysics Data System (ADS)

    van Dyk, David A.; Protassov, Rostislav; Kashyap, Vinay L.; Siemiginowska, Aneta; Connors, Alanna

    1999-04-01

    Recently Bayesian methods have grown rapidly in popularity in many scientific disciplines as several computationally intensive statistical algorithms have become feasible with modern computer power. In this paper, we demonstrate how we have employed these state-of-the-art techniques (e.g., Gibbs sampler and Metropolis-Hastings) to fit today's high-quality, high resolution astrophysical spectral data. These algorithms are very flexible and can be used to fit models that account for the highly hierarchical structure in the collection of high-quality spectra and thus can keep pace with the accelerating progress of new telescope designs. We explicitly model photon arrivals as a Poisson process and, thus, have no difficulty with high resolution low count X-ray and gamma-ray data. These methods will be useful not only for the soon-to-be-launched Chandra X-ray observatory but also such new generation telescopes as XMM, Constellation X, and GLAST. We also explicitly incorporate the instrument response (e.g. via a response matrix and effective area vector), plus background contamination of the data. In particular, we appropriately model the background as the realization of a second Poisson process, thereby eliminating the need to directly subtract off the background counts and the rather embarrassing problem of negative photon counts. The source energy spectrum is modeled as a mixture of a Generalized Linear Model which accounts for the continuum plus absorption and several (Gaussian) line profiles. Generalized Linear Models are the standard method for incorporating covariate information (as in regression) into non-Gaussian models and are thus an obvious but innovative choice in this setting. Using several examples, we illustrate how Bayesian posterior sampling can be used to compute point (i.e., ``best'') estimates of the various model parameters as well as compute error bars on these estimates and construct statistical tests.

  13. Singular spectrum analysis and adaptive filtering enhance the functional connectivity analysis of resting state fMRI data.

    PubMed

    Piaggi, Paolo; Menicucci, Danilo; Gentili, Claudio; Handjaras, Giacomo; Gemignani, Angelo; Landi, Alberto

    2014-05-01

    Sources of noise in resting-state fMRI experiments include instrumental and physiological noises, which need to be filtered before a functional connectivity analysis of brain regions is performed. These noisy components show autocorrelated and nonstationary properties that limit the efficacy of standard techniques (i.e. time filtering and general linear model). Herein we describe a novel approach based on the combination of singular spectrum analysis and adaptive filtering, which allows a greater noise reduction and yields better connectivity estimates between regions at rest, providing a new feasible procedure to analyze fMRI data.

  14. Gamma spectrum unfolding for a NaI monitor of radioactivity in aquatic systems: experimental evaluations of the minimal detectable activity.

    PubMed

    Baré, J; Tondeur, F

    2011-08-01

    This paper deals with the experimental evaluation of the minimal detectable activity achievable by unfolding the gamma spectra of a NaI monitor. An aquatic monitor initially developed by the Institut des Radio-Eléments (IRE) is used for the application. Unfolding of the spectra is performed with GRAVEL, a UMG package code, on the basis of a response matrix obtained with MCNP5.1.40. Experimental data have been measured at IRE, in a 20m(3) seawater tank, for known activities of (137)Cs mixed with other gamma emitters ((40)K, (133)Ba, (113)Sn and (139)Ce). Deconvolution allows one to reduce the MDA of (137)Cs by an order of magnitude. PMID:21146415

  15. The Multi-Isotope Process Monitor: Multivariate Analysis of Gamma Spectra

    SciTech Connect

    Orton, Christopher R.; Rutherford, Crystal E.; Fraga, Carlos G.; Schwantes, Jon M.

    2011-10-30

    The International Atomic Energy Agency (IAEA) has established international safeguards standards for fissionable material at spent fuel reprocessing plants to ensure that significant quantities of nuclear material are not diverted from these facilities. Currently, methods to verify material control and accountancy (MC&A) at these facilities require time-consuming and resource-intensive destructive assay (DA). The time delay between sampling and subsequent DA provides a potential opportunity to divert the material out of the appropriate chemical stream. Leveraging new on-line nondestructive assay (NDA) techniques in conjunction with the traditional and highly precise DA methods may provide a more timely, cost-effective and resource efficient means for MC&A verification at such facilities. Pacific Northwest National Laboratory (PNNL) is developing on-line NDA process monitoring technologies, including the Multi-Isotope Process (MIP) Monitor. The MIP Monitor uses gamma spectroscopy and pattern recognition software to identify off-normal conditions in process streams. Recent efforts have been made to explore the basic limits of using multivariate analysis techniques on gamma-ray spectra. This paper will provide an overview of the methods and report our on-going efforts to develop and demonstrate the technology.

  16. Localization of T cell receptor (TCR)-gamma delta + T cells into human colorectal cancer: flow cytometric analysis of TCR-gamma delta expression in tumour-infiltrating lymphocytes.

    PubMed Central

    Watanabe, N; Hizuta, A; Tanaka, N; Orita, K

    1995-01-01

    We analysed TCR-gamma delta expression in tumour-infiltrating lymphocytes (TIL) obtained from 13 patients with colorectal cancer and simultaneously isolated the T lymphocytes from normal intestinal tissue (IL) to compare the frequencies of TCR-gamma delta expression in TIL, IL, and peripheral blood lymphocytes (PBL) in the same patient. Flow cytometric analysis showed that the frequency of TCR-gamma delta expression in TIL (2.75 +/- 1.84%) was significantly lower than that in IL (15.28 +/- 9.45%, P < 0.01). However, a larger quantity of TIL was separated than IL per unit weight of specimen, so the total number of gamma delta T cells obtained per unit weight was not different between tumour tissue and normal intestine. In addition, phenotypic analysis revealed that about half of the TCR-gamma delta + TIL were CD8+ (CD4+, 3.0 +/- 3.1%; CD8+, 54.7 +/- 19.9%, mean +/- s.d. of five patients), and a very similar result was obtained in TCR-gamma delta + IL (CD4+, 2.7 +/- 2.4%; CD8+, 53.1 +/- 17.4%). In contrast, most TCR-gamma delta + PBL were double-negative (CD4+, 3.2 +/- 3.0%; CD8+, 20.6 +/- 7.4%). These results indicated that TCR-gamma delta + CD8+ T cells selectively and consistently localized in colorectal tumour tissue, similarly to normal intestinal epithelium. PMID:7554384

  17. Characterization of HPGe gamma spectrometric detectors systems for Instrumental Neutron Activation Analysis (INAA) at the Colombian Geological Survey

    NASA Astrophysics Data System (ADS)

    Sierra, O.; Parrado, G.; Cañón, Y.; Porras, A.; Alonso, D.; Herrera, D. C.; Peña, M.; Orozco, J.

    2016-07-01

    This paper presents the progress made by the Neutron Activation Analysis (NAA) laboratory at the Colombian Geological Survey (SGC in its Spanish acronym), towards the characterization of its gamma spectrometric systems for Instrumental Neutron Activation Analysis (INAA), with the aim of introducing corrections to the measurements by variations in sample geometry. Characterization includes the empirical determination of the interaction point of gamma radiation inside the Germanium crystal, through the application of a linear model and the use of a fast Monte Carlo N-Particle (MCNP) software to estimate correction factors for differences in counting efficiency that arise from variations in sample density between samples and standards.

  18. [Near-infrared spectrum quantitative analysis model based on principal components selected by elastic net].

    PubMed

    Chen, Wan-hui; Liu, Xu-hua; He, Xiong-kui; Min, Shun-geng; Zhang, Lu-da

    2010-11-01

    Elastic net is an improvement of the least-squares method by introducing in L1 and L2 penalties, and it has the advantages of the variable selection. The quantitative analysis model build by Elastic net can improve the prediction accuracy. Using 89 wheat samples as the experiment material, the spectrum principal components of the samples were selected by Elastic net. The analysis model was established for the near-infrared spectrum and the wheat's protein content, and the feasibility of using Elastic net to establish the quantitative analysis model was confirmed. In experiment, the 89 wheat samples were randomly divided into two groups, with 60 samples being the model set and 29 samples being the prediction set. The 60 samples were used to build analysis model to predict the protein contents of the 29 samples, and correlation coefficient (R) of the predicted value and chemistry observed value was 0. 984 9, with the mean relative error being 2.48%. To further investigate the feasibility and stability of the model, the 89 samples were randomly selected five times, with 60 samples to be model set and 29 samples to be prediction set. The five groups of principal components which were selected by Elastic net for building model were basically consistent, and compared with the PCR and PLS method, the model prediction accuracies were all better than PCR and similar with PLS. In view of the fact that Elastic net can realize the variable selection and the model has good prediction, it was shown that Elastic net is suitable method for building chemometrics quantitative analysis model. PMID:21284156

  19. Cathodoluminescence Spectrum Imaging Software

    2011-04-07

    The software developed for spectrum imaging is applied to the analysis of the spectrum series generated by our cathodoluminescence instrumentation. This software provides advanced processing capabilities s such: reconstruction of photon intensity (resolved in energy) and photon energy maps, extraction of the spectrum from selected areas, quantitative imaging mode, pixel-to-pixel correlation spectrum line scans, ASCII, output, filling routines, drift correction, etc.

  20. Quantitative analysis of volatiles in edible oils following accelerated oxidation using broad spectrum isotope standards

    PubMed Central

    Gómez-Cortés, Pilar; Sacks, Gavin L.; Brenna, J. Thomas

    2014-01-01

    Analysis of food volatiles generated by processing are widely reported but comparisons across studies is challenging in part because most reports are inherently semi-quantitative for most analytes due to limited availability of chemical standards. We recently introduced a novel strategy for creation of broad spectrum isotopic standards for accurate quantitative food chemical analysis. Here we apply the principle to quantification of 25 volatiles in seven thermally oxidized edible oils. After extended oxidation, total volatiles of high n-3 oils (flax, fish, cod liver) were 120-170 mg/kg while low n-3 vegetable oils were <50 mg/kg. Separate experiments on thermal degradation of d5-ethyl linolenate indicate that off-aroma volatiles originate throughout the n-3 molecule and not solely the n-3 terminal end. These data represent the first report using broad-spectrum isotopically labeled standards for quantitative characterization of processing-induced volatile generation across related foodstuffs, and verify the origin of specific volatiles from parent n-3 fatty acids. PMID:25529686

  1. EVALUATING THE HYDROGEOCHEMICAL RESPONSE OF SPRINGS USING PHASE-PLANE PLOTS AND SINGULAR SPECTRUM ANALYSIS

    SciTech Connect

    B. NEWMAN; C. DUFFY; D. HICKMOTT

    2001-04-01

    An ongoing study is focused on understanding the hydrology and geochemistry of three contaminated, perennial, semi-arid zone springs at a high explosives production facility at Los Alamos National Laboratory, in northern New Mexico, USA. Springflow time series were examined using singular spectrum analysis (SSA) to identify the important time-scales affecting flow in the springs. SSA results suggest that springflow has two dominant patterns: a series of low-frequency modes which follow the seasonal and longer-term climate conditions at the site, and a large number of higher frequency modes which display the characteristic ''red noise'' spectrum related to local, short-term weather conditions. Phase-plane plots of {delta}{sup 18}O and spring discharge suggest that high flow conditions are dominated by snowmelt and summer monsoon inputs while low flow conditions can be affected by mixing of fast and slow flow components causing wide variations in {delta}{sup 18}O values. The analysis is being used for development of an efficient strategy for sampling design for environmental monitoring of contaminants that respond to multiple time scales.

  2. Ion-induced gamma-ray detection of fast ions escaping from fusion plasmas

    SciTech Connect

    Nishiura, M. Mushiake, T.; Doi, K.; Wada, M.; Taniike, A.; Matsuki, T.; Shimazoe, K.; Yoshino, M.; Nagasaka, T.; Tanaka, T.; Kisaki, M.; Fujimoto, Y.; Fujioka, K.; Yamaoka, H.; Matsumoto, Y.

    2014-11-15

    A 12 × 12 pixel detector has been developed and used in a laboratory experiment for lost fast-ion diagnostics. With gamma rays in the MeV range originating from nuclear reactions {sup 9}Be(α, nγ){sup 12}C, {sup 9}Be(d, nγ){sup 12}C, and {sup 12}C(d, pγ){sup 13}C, a high purity germanium (HPGe) detector measured a fine-energy-resolved spectrum of gamma rays. The HPGe detector enables the survey of background-gamma rays and Doppler-shifted photo peak shapes. In the experiments, the pixel detector produces a gamma-ray image reconstructed from the energy spectrum obtained from total photon counts of irradiation passing through the detector's lead collimator. From gamma-ray image, diagnostics are able to produce an analysis of the fast ion loss onto the first wall in principle.

  3. Factor analysis of the aberrant behavior checklist in individuals with autism spectrum disorders.

    PubMed

    Brinkley, Jason; Nations, Laura; Abramson, Ruth K; Hall, Alicia; Wright, Harry H; Gabriels, Robin; Gilbert, John R; Pericak-Vance, Margaret A O; Cuccaro, Michael L

    2007-11-01

    Exploratory factor analysis (varimax and promax rotations) of the aberrant behavior checklist-community version (ABC) in 275 individuals with Autism spectrum disorder (ASD) identified four- and five-factor solutions which accounted for >70% of the variance. Confirmatory factor analysis (Lisrel 8.7) revealed indices of moderate fit for the five-factor solution. Our results suggest that the factor structure of the ABC is robust within an ASD sample. Both solutions yielded a three items self-injury factor. Stratifying on this factor, we identified significant differences between the high- and low-self injury groups on ABC subscales. The emergence of a self-injury factor, while not suggestive of a new subscale, warrants further exploration as a tool that could help dissect relevant neurobiobehavioral groups in ASD.

  4. A glance at the applications of Singular Spectrum Analysis in gene expression data.

    PubMed

    Hassani, Hossein; Ghodsi, Zara

    2015-06-01

    In recent years Singular Spectrum Analysis (SSA) has been used to solve many biomedical issues and is currently accepted as a potential technique in quantitative genetics studies. Presented in this article is a review of recent published genetics studies which have taken advantage of SSA. Since Singular Value Decomposition (SVD) is an important stage of this technique which can also be used as an independent analytical method in gene expression data, we also briefly touch upon some areas of the application of SVD. The review finds that at present, the most prominent area of applying SSA in genetics is filtering and signal extraction, which proves that SSA can be considered as a valuable aid and promising method for genetics analysis.

  5. Transient Safety Analysis of Fast Spectrum TRU Burning LWRs with Internal Blankets

    SciTech Connect

    Downar, Thomas; Zazimi, Mujid; Hill, Bob

    2015-01-31

    The objective of this proposal was to perform a detailed transient safety analysis of the Resource-Renewable BWR (RBWR) core designs using the U.S. NRC TRACE/PARCS code system. This project involved the same joint team that has performed the RBWR design evaluation for EPRI and therefore be able to leverage that previous work. And because of their extensive experience with fast spectrum reactors and parfait core designs, ANL was also part the project team. The principal outcome of this project was the development of a state-of-the-art transient analysis capability for GEN-IV reactors based on Monte Carlo generated cross sections and the US NRC coupled code system TRACE/PARCS, and a state-of-the-art coupled code assessment of the transient safety performance of the RBWR.

  6. Reliability of prompt gamma-ray analysis for the determination of Na and Mg in rock samples.

    PubMed

    Karouji, Yuzuru; Ebihara, Mitsuru

    2008-05-01

    The reliability of neutron-induced prompt gamma-ray analysis (PGA) was examined for the determination of Na and Mg in geological and cosmochemical rock samples, because they tend to have been erroneously determined for such samples. JB-1 (basalt standard rock) and Allende (chondritic meteorite) powder samples were repeatedly analyzed by using thermal or cold neutron-guided beams of the JRR-3M research reactor at Japan Atomic Energy Agency. In critically evaluating calculated values for major prompt gamma-rays of Na and Mg, it was observed that a 472.2 keV peak for Na and a 2828.2 keV peak for Mg yielded reasonable consistency with corresponding recommended values. Sodium and Mg were determined for five lunar meteorites by PGA using these prompt gamma-rays, and were found to be consistent with their data obtained by instrumental neutron activation analysis.

  7. Analysis of proposed gamma-ray detection system for the monitoring of core water inventory in a pressurized water reactor

    SciTech Connect

    Markoff, D.M.

    1987-12-01

    An initial study has been performed of the feasibility of employing an axial array of gamma detectors located outside the pressure vessel to monitor the coolant in a PWR. A one-dimensional transport analysis model is developed for the LOFT research reactor and for a mock-PWR geometry. The gamma detector response to coolant voiding in the core and downcomer has been determined for both geometries. The effects of various conditions (for example, time after shutdown, materials in the transport path, and the relative void fraction in different water regions) on the detector response are studied. The calculational results have been validated by a favorable comparison with LOFT experimental data. Within the limitations and approximations considered in the analysis, the results indicate that the gamma-ray detection scheme is able to unambiguously respond to changes in the coolant inventory within any vessel water region.

  8. Rigidity spectrum of Forbush decrease

    NASA Technical Reports Server (NTRS)

    Sakakibara, S.; Munakata, K.; Nagashima, K.

    1985-01-01

    Using data from neutron monitors and muon telescopes at surface and underground stations, the average rigidity spectrum of Forbush decreases (Fds) during the period of 1978-1982 were obtained. Thirty eight Ed-events are classified into two groups Hard Fd and Soft Fd according to size of Fd at Sakashita station. It is found that a spectral form of fractional-power type (P to the-gamma sub 1 (P+P sub c) to the -gamma sub2) is more suitable for the present purpose than that of power-exponential type or of power type with an upper limiting rigidity. The best fitted spectrum of fractional-power type is expressed by gamma sub1 = 0.37, gamma sub2 = 0.89 and P subc = 10 GV for Hard Fd and gamma sub1 = 0.77, gamma sub2 = 1.02 and P sub c - 14GV for Soft Fd.

  9. TURBULENCE SPECTRA FROM DOPPLER-BROADENED SPECTRAL LINES: TESTS OF THE VELOCITY CHANNEL ANALYSIS AND VELOCITY COORDINATE SPECTRUM TECHNIQUES

    SciTech Connect

    Chepurnov, A.; Lazarian, A.

    2009-03-10

    Turbulent motions induce Doppler shifts of observable emission and absorption lines motivating studies of turbulence using precision spectroscopy. We provide numerical testing of the two most promising techniques, velocity channel analysis and velocity coordinate spectrum (VCS). We obtain an expression for the shot noise that the discretization of the numerical data entails and successfully test it. We show that the numerical resolution required for recovering the underlying turbulent spectrum from observations depend on the spectral index of velocity fluctuations, which makes low-resolution testing misleading. We demonstrate numerically that, when dealing with absorption lines, sampling of turbulence along just a dozen directions provides a high quality spectrum with the VCS technique.

  10. [Analysis of the character of film decomposition of methyl methacrylate (MMA) coated urea by infrared spectrum].

    PubMed

    Li, Dong-po; Wu, Zhi-jie; Liang, Cheng-hua; Chen, Li-jun; Zhang, Yu-lan; Nie, Yan-xi

    2012-03-01

    The degradability characteristics of film with 4 kinds of methyl methacrylate coated urea amended with inhibitors were analyzed by FITR, which was purposed to supply theoretical basis for applying the FITR analysis method to film decomposition and methyl methacrylate coated urea fertilizers on farming. The result showed that the chemical component, molecule structure and material form of the membrane were not changed because of adding different inhibitors to urea. the main peaks of expressing film degradation process were brought by the -C-H of CH3 & CH2, -OH, C-O, C-C, C-O-C, C=O, C=C flexing vibrancy in asymmetry and symmetry in 3 479-3 195, 2 993--2 873, 1 741-1 564, 1 461-925 and 850-650 cm(-1). The peak value changed from smooth to tip, and from width to narrow caused by chemical structural transform of film The infrared spectrum of 4 kinds of fertilizers was not different remarkably before 60 days, and the film was slowly degraded. But degradation of the film was expedited after 60 days, it was most quickened at 120 day, and the decomposition rate of film was decreased at 310 day. The substantiality change of film in main molecule structure of 4 kinds of fertilizers didn't happen in 310 days. The main component of film materials was degraded most slowly in brown soil. The speed of film degradation wasn't heavily impacted by different inhibitors. The characteristic of film degradation may be monitored entirely by infrared spectrum. The degradation dynamic, chemical structure change, degradation speed difference of the film could be represented through infrared spectrum. PMID:22582622

  11. [Analysis of the character of film decomposition of methyl methacrylate (MMA) coated urea by infrared spectrum].

    PubMed

    Li, Dong-po; Wu, Zhi-jie; Liang, Cheng-hua; Chen, Li-jun; Zhang, Yu-lan; Nie, Yan-xi

    2012-03-01

    The degradability characteristics of film with 4 kinds of methyl methacrylate coated urea amended with inhibitors were analyzed by FITR, which was purposed to supply theoretical basis for applying the FITR analysis method to film decomposition and methyl methacrylate coated urea fertilizers on farming. The result showed that the chemical component, molecule structure and material form of the membrane were not changed because of adding different inhibitors to urea. the main peaks of expressing film degradation process were brought by the -C-H of CH3 & CH2, -OH, C-O, C-C, C-O-C, C=O, C=C flexing vibrancy in asymmetry and symmetry in 3 479-3 195, 2 993--2 873, 1 741-1 564, 1 461-925 and 850-650 cm(-1). The peak value changed from smooth to tip, and from width to narrow caused by chemical structural transform of film The infrared spectrum of 4 kinds of fertilizers was not different remarkably before 60 days, and the film was slowly degraded. But degradation of the film was expedited after 60 days, it was most quickened at 120 day, and the decomposition rate of film was decreased at 310 day. The substantiality change of film in main molecule structure of 4 kinds of fertilizers didn't happen in 310 days. The main component of film materials was degraded most slowly in brown soil. The speed of film degradation wasn't heavily impacted by different inhibitors. The characteristic of film degradation may be monitored entirely by infrared spectrum. The degradation dynamic, chemical structure change, degradation speed difference of the film could be represented through infrared spectrum.

  12. TOPICAL REVIEW: Human soft tissue analysis using x-ray or gamma-ray techniques

    NASA Astrophysics Data System (ADS)

    Theodorakou, C.; Farquharson, M. J.

    2008-06-01

    This topical review is intended to describe the x-ray techniques used for human soft tissue analysis. X-ray techniques have been applied to human soft tissue characterization and interesting results have been presented over the last few decades. The motivation behind such studies is to provide improved patient outcome by using the data obtained to better understand a disease process and improve diagnosis. An overview of theoretical background as well as a complete set of references is presented. For each study, a brief summary of the methodology and results is given. The x-ray techniques include x-ray diffraction, x-ray fluorescence, Compton scattering, Compton to coherent scattering ratio and attenuation measurements. The soft tissues that have been classified using x-rays or gamma rays include brain, breast, colon, fat, kidney, liver, lung, muscle, prostate, skin, thyroid and uterus.

  13. On the accuracy of protein determination in large biological samples by prompt gamma neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Kasviki, K.; Stamatelatos, I. E.; Yannakopoulou, E.; Papadopoulou, P.; Kalef-Ezra, J.

    2007-10-01

    A prompt gamma neutron activation analysis (PGNAA) facility has been developed for the determination of nitrogen and thus total protein in large volume biological samples or the whole body of small animals. In the present work, the accuracy of nitrogen determination by PGNAA in phantoms of known composition as well as in four raw ground meat samples of about 1 kg mass was examined. Dumas combustion and Kjeldahl techniques were also used for the assessment of nitrogen concentration in the meat samples. No statistically significant differences were found between the concentrations assessed by the three techniques. The results of this work demonstrate the applicability of PGNAA for the assessment of total protein in biological samples of 0.25-1.5 kg mass, such as a meat sample or the body of small animal even in vivo with an equivalent radiation dose of about 40 mSv.

  14. Boron analysis for neutron capture therapy using particle-induced gamma-ray emission.

    PubMed

    Nakai, Kei; Yamamoto, Yohei; Okamoto, Emiko; Yamamoto, Tetsuya; Yoshida, Fumiyo; Matsumura, Akira; Yamada, Naoto; Kitamura, Akane; Koka, Masashi; Satoh, Takahiro

    2015-12-01

    The neutron source of BNCT is currently changing from reactor to accelerator, but peripheral facilities such as a dose-planning system and blood boron analysis have still not been established. To evaluate the potential application of particle-induced gamma-ray emission (PIGE) for boron measurement in clinical boron neutron capture therapy, boronophenylalanine dissolved within a cell culture medium was measured using PIGE. PIGE detected 18 μgB/mL f-BPA in the culture medium, and all measurements of any given sample were taken within 20 min. Two hours of f-BPA exposure was required to create a boron distribution image. However, even though boron remained in the cells, the boron on the cell membrane could not be distinguished from the boron in the cytoplasm.

  15. Galaxy formation from annihilation-generated supersonic turbulence in the baryon-symmetric big-bang cosmology and the gamma ray background spectrum

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.; Puget, J. L.

    1972-01-01

    Following the big-bang baryon symmetric cosmology of Omnes, the redshift was calculated to be on the order of 500-600. It is show that, at these redshifts, annihilation pressure at the boundaries between regions of matter and antimatter drives large scale supersonic turbulence which can trigger galaxy formation. This picture is consistent with the gamma-ray background observations discussed previously. Gravitational binding of galaxies then occurs at a redshift of about 70, at which time vortical turbulent velocities of about 3 x 10 to the 7th power cm/s lead to angular momenta for galaxies comparable with measured values.

  16. Frequency spectrum method-based stress analysis for oil pipelines in earthquake disaster areas.

    PubMed

    Wu, Xiaonan; Lu, Hongfang; Huang, Kun; Wu, Shijuan; Qiao, Weibiao

    2015-01-01

    When a long distance oil pipeline crosses an earthquake disaster area, inertial force and strong ground motion can cause the pipeline stress to exceed the failure limit, resulting in bending and deformation failure. To date, researchers have performed limited safety analyses of oil pipelines in earthquake disaster areas that include stress analysis. Therefore, using the spectrum method and theory of one-dimensional beam units, CAESAR II is used to perform a dynamic earthquake analysis for an oil pipeline in the XX earthquake disaster area. This software is used to determine if the displacement and stress of the pipeline meet the standards when subjected to a strong earthquake. After performing the numerical analysis, the primary seismic action axial, longitudinal and horizontal displacement directions and the critical section of the pipeline can be located. Feasible project enhancement suggestions based on the analysis results are proposed. The designer is able to utilize this stress analysis method to perform an ultimate design for an oil pipeline in earthquake disaster areas; therefore, improving the safe operation of the pipeline.

  17. A Meta-Analysis of Maternal Smoking during Pregnancy and Autism Spectrum Disorder Risk in Offspring.

    PubMed

    Tang, Shiming; Wang, Ying; Gong, Xuan; Wang, Gaohua

    2015-09-01

    The association between maternal smoking during pregnancy and autism spectrum disorder (ASD) risk in offspring has been investigated in several studies, but the evidence is not conclusive. We, therefore, conducted this meta-analysis to explore whether an association exists between maternal smoking during pregnancy and ASD risk in offspring. We searched PubMed, Embase, Web of Science, and the Cochrane Library for studies of maternal smoking during pregnancy and ASD risk in offspring up to 10 June 2015. The random-effects model was used to combine results from individual studies. 15 observational studies (6 cohort studies and 9 case-control studies), with 17,890 ASD cases and 1,810,258 participants were included for analysis. The pooled odds ratio (OR) was 1.02 (95% confidence interval (CI): 0.93-1.13) comparing mothers who smoked during pregnancy with those who did not. Subgroup and sensitivity analysis suggested the overall result of this analysis was robust. Results from this meta-analysis indicate that maternal smoking during pregnancy is not associated with ASD risk in offspring. Further well-designed cohort studies are needed to confirm the present findings.

  18. Frequency Spectrum Method-Based Stress Analysis for Oil Pipelines in Earthquake Disaster Areas

    PubMed Central

    Wu, Xiaonan; Lu, Hongfang; Huang, Kun; Wu, Shijuan; Qiao, Weibiao

    2015-01-01

    When a long distance oil pipeline crosses an earthquake disaster area, inertial force and strong ground motion can cause the pipeline stress to exceed the failure limit, resulting in bending and deformation failure. To date, researchers have performed limited safety analyses of oil pipelines in earthquake disaster areas that include stress analysis. Therefore, using the spectrum method and theory of one-dimensional beam units, CAESAR II is used to perform a dynamic earthquake analysis for an oil pipeline in the XX earthquake disaster area. This software is used to determine if the displacement and stress of the pipeline meet the standards when subjected to a strong earthquake. After performing the numerical analysis, the primary seismic action axial, longitudinal and horizontal displacement directions and the critical section of the pipeline can be located. Feasible project enhancement suggestions based on the analysis results are proposed. The designer is able to utilize this stress analysis method to perform an ultimate design for an oil pipeline in earthquake disaster areas; therefore, improving the safe operation of the pipeline. PMID:25692790

  19. Analysis of neutron spectrum effects on primary damage in tritium breeding blankets

    NASA Astrophysics Data System (ADS)

    Choi, Yong Hee; Joo, Han Gyu

    2012-07-01

    The effect of neutron spectrum on primary damages in a structural material of a tritium breeding blanket is investigated with a newly established recoil spectrum estimation system. First, a recoil spectrum generation code is developed to obtain the energy spectrum of primary knock-on atoms (PKAs) for a given neutron spectrum utilizing the latest ENDF/B data. Secondly, a method for approximating the high energy tail of the recoil spectrum is introduced to avoid expensive molecular dynamics calculations for high energy PKAs using the concept of recoil energy of the secondary knock-on atoms originated by the INtegration of CAScades (INCAS) model. Thirdly, the modified spectrum is combined with a set of molecular dynamics calculation results to estimate the primary damage parameters such as the number of surviving point defects. Finally, the neutron spectrum is varied by changing the material of the spectral shifter and the result in primary damage parameters is examined.

  20. Morphometric analysis in gamma-ray astronomy using Minkowski functionals. Source detection via structure quantification

    NASA Astrophysics Data System (ADS)

    Göring, D.; Klatt, M. A.; Stegmann, C.; Mecke, K.

    2013-07-01

    Aims: H.E.S.S. observes an increasing number of large extended sources. A new technique based on the structure of the sky map is developed to account for these additional structures by comparing them with the common point source analysis. Methods: Minkowski functionals are powerful measures from integral geometry. They can be used to quantify the structure of the counts map, which is then compared with the expected structure of a pure Poisson background. Gamma-ray sources lead to significant deviations from the expected background structure. The standard likelihood ratio method is exclusively based on the number of excess counts and discards all further structure information of large extended sources. The morphometric data analysis incorporates this additional geometric information in an unbiased analysis, i.e., without the need of any prior knowledge about the source. Results: We have successfully applied our method to data of the H.E.S.S. experiment. The morphometric analysis presented here is dedicated to detecting faint extended sources.

  1. A Calibration to Predict Concentrations of Impurities in Plutonium Oxide by Prompt Gamma Analysis

    SciTech Connect

    J.E. Narlesky; E.J. Kelly; L.A. Foster

    2005-12-13

    Prompt gamma (PG) analysis has been used to identify the presence of certain impurities in plutonium oxide, which has been stored in 3013 containers. A regression analysis was used to evaluate the trends between the count rates obtained from PG analysis and the concentration of the impurities in plutonium oxide samples measured by analytical chemistry techniques. The results of the analysis were used to obtain calibration curves, which may be used to predict the concentration of Al, Be, Cl, F, Mg, and Na in the 3013 containers. The scatter observed in the data resulted from several factors including sample geometry, error in sampling for chemical assay, statistical counting error, and intimacy of mixing of impurities and plutonium. Standards prepared by mixing plutonium oxide with CaF{sub 2}, NaCl, and KCl show that intimacy mixing and sampling error have the largest influence on the results. Although these factors are difficult to control, the calibrations are expected to yield semiquantitative results that are sufficient for the purpose of ordering or ranking.

  2. Infrared spectrum analysis of the dissociated states of simple amino acids.

    PubMed

    Sebben, Damien; Pendleton, Phillip

    2014-11-11

    In this work, we present detailed analyses of the dissociation of dilute aqueous solutions of glycine and of lysine over the range 1spectrum subtraction methods, we obtained ATR-IR spectra of the solvated species as a function of pH. Discernible changes in the ionic species were identified in the absorption region between 1800 and 1100 cm(-1). By applying peak deconvolution techniques to the spectra, we correctly interpret the apparent peak shift from 1615 to 1600 cm(-1) as being due to the receding NH3+ asymmetric deformation alongside the appearing COO- asymmetric stretching. The effect of aqueous solution environment was also investigated in terms of 10 and 100 mmol/L NaCl. Salt solution spectra at each pH were also subtracted from each solution phase spectrum. Analysis of the deconvoluted peak areas due to CO and COO- at pH ranges<4.5 and those due to NH2 and NH3+ for pH>8 resulted in consistent pKa values for the amino acids.

  3. [The nitrate and temperature impact analysis in the detection of COD by UV spectrum].

    PubMed

    Bi, Wei-Hong; Li, Jian-Guo; Wu, Guo-Qing; Fu, Xing-Hu; Fu, Guang-Wei

    2014-03-01

    Configured standard solution of chemical oxygen demand with potassium hydrogen phthalate was used as experimental subjects, collected ultraviolet absorption spectra of the standard solution in the range of 1,800 mg x L(-1), were collected, and PLS (partial least squares) algorithm was used to establish the correction model of different spectral region, the results showed that. The model in the spectral region of 265-310 nm had the highest correlation and smallest error; In order to eliminate the impact of nitrates and temperature on the detection of the COD , studied the changes of the UV absorption spectrum with different concentrations of sodium standard solution and different temperature. The results showed that absorption of nitrate in 208-238 nm was apparent, and the model for spectral region of 265-310 nm was free from the influence of nitrate; In the full range of spectrum, temperature rising leads to an increase in absorbance, thus the temperature compensation model was established for the different spectral region through predictive analysis.

  4. A meta-analysis of the reading comprehension skills of individuals on the autism spectrum.

    PubMed

    Brown, Heather M; Oram-Cardy, Janis; Johnson, Andrew

    2013-04-01

    This meta-analysis examined 36 studies comparing autism spectrum disorder (ASD) and control groups in reading comprehension. Three moderators (semantic knowledge, decoding skill, PIQ) and two text types (high vs. low social knowledge) were examined as predictors of reading comprehension in ASD. The overall standardized mean difference for reading comprehension was g = -0.7 SD. The strongest individual predictors of reading comprehension were semantic knowledge (explaining 57 % of variance) and decoding skill (explaining 55 % of variance). Individuals with ASD were significantly worse at comprehending highly social than less social texts. Having ASD alone does not predict reading comprehension deficits. Instead, individual skills, especially language ability, must be considered before one can accurately predict whether a given individual with ASD will experience difficulties in reading comprehension.

  5. Singular Spectrum Analysis: A Note on Data Processing for Fourier Transform Hyperspectral Imagers.

    PubMed

    Rafert, J Bruce; Zabalza, Jaime; Marshall, Stephen; Ren, Jinchang

    2016-09-01

    Hyperspectral remote sensing is experiencing a dazzling proliferation of new sensors, platforms, systems, and applications with the introduction of novel, low-cost, low-weight sensors. Curiously, relatively little development is now occurring in the use of Fourier transform (FT) systems, which have the potential to operate at extremely high throughput without use of a slit or reductions in both spatial and spectral resolution that thin film based mosaic sensors introduce. This study introduces a new physics-based analytical framework called singular spectrum analysis (SSA) to process raw hyperspectral imagery collected with FT imagers that addresses some of the data processing issues associated with the use of the inverse FT. Synthetic interferogram data are analyzed using SSA, which adaptively decomposes the original synthetic interferogram into several independent components associated with the signal, photon and system noise, and the field illumination pattern.

  6. An Analysis of the Rotational Spectrum of Acetonitrile (CH_3CN) in Excited Vibrational States

    NASA Astrophysics Data System (ADS)

    Neese, Christopher F.; McMillan, James; Fortman, Sarah; De Lucia, Frank C.

    2014-06-01

    Acetonitrile (CH_3CN) is a well-known interstellar molecule whose vibrationally excited states need to be accounted for in searches for new molecules in the interstellar medium. To help catalog such `weed' molecules, we have developed a technique that involves recording complete spectra over a range of astrophysically significant temperatures. With such a data set, we can experimentally measure the line strengths and lower state energies of unassigned lines in the spectrum. In this talk we will present the ongoing analysis of complete temperature resolved spectra in the 215-265 GHz and 570-650 GHz regions. We have been able to assign many vibrationally hot lines from this data and a room temperature data set spanning 165-700 GHz. To date, we have assigned lines from most of the vibrational states below ν_6 at 1448 wn.

  7. The sensory experiences of adults with autism spectrum disorder: A qualitative analysis.

    PubMed

    Robertson, Ashley E; David R Simmons, R

    2015-01-01

    It has been well established that individuals with autism spectrum disorder report unusual experiences with sensory stimuli compared with typically developing individuals. However, there is a paucity of research exploring the nature of such experiences. A focus group was conducted with six adults with a diagnosis of autism or Asperger syndrome. Data were coded and analysed using an inductive, qualitative thematic analysis. Four main themes encompassing both positive and negative sensory experiences emerged from these data: (a) the importance of particular aspects of stimuli in their perception, (b) the importance of having control over stimuli, (c) how emotions/mental states could impact/be impacted by sensory stimuli, and (d) physical responses to stimuli. These data are discussed alongside extant literature. Limitations, possible implications, and potential directions of future research are also discussed.

  8. Numerical analysis of the beam quality and spectrum of wavelength-beam-combined laser diode arrays

    NASA Astrophysics Data System (ADS)

    Tang, Xuan; Wang, Xiao-Jun; Ke, Wei-Wei

    2015-02-01

    In this paper, a numerical model is presented to simulation the performance of the wavelength-beam-combined laser diode arrays (LDA) system. The eigen mode expansion method is used to describe the two-dimensional optical amplification and the strength of field feedback of external cavity. To describe the mode competition in laser diodes, the gain saturation effect is considered. The two-dimension distributions of the carrier concentration, recombination rates, and optical gain are calculated for solving the laser dynamic equation. The Fresnel integration, grating equation and mode overlap integration are used to obtain the feedback coefficient of extent cavity diffraction. Quantum noise is considered to evaluate the spectral linewidth of semiconductor laser. Based on the numerical model, the impact of the mutual optical feedback on the beam quality and spectrum of the LDA is present and analysis.

  9. Enhancing multivariate singular spectrum analysis for phase synchronization: The role of observability

    NASA Astrophysics Data System (ADS)

    Portes, Leonardo L.; Aguirre, Luis A.

    2016-09-01

    Multivariate singular spectrum analysis (M-SSA) was recently adapted to study systems of coupled oscillators. It does not require an a priori definition for phase nor detailed knowledge of the individual oscillators, but it uses all the variables of each system. This aspect could be restrictive for practical applications, since usually just a few (sometimes only one) variables are measured. Based on dynamical systems and observability theories, we first show how to apply the M-SSA with only one variable and show the conditions to achieve good performance. Next, we provide numerical evidence that this single-variable approach enhances the explanatory power compared to the original M-SSA when computed with all the system variables. This could have important practical implications, as pointed out using benchmark oscillators.

  10. The sensory experiences of adults with autism spectrum disorder: A qualitative analysis.

    PubMed

    Robertson, Ashley E; David R Simmons, R

    2015-01-01

    It has been well established that individuals with autism spectrum disorder report unusual experiences with sensory stimuli compared with typically developing individuals. However, there is a paucity of research exploring the nature of such experiences. A focus group was conducted with six adults with a diagnosis of autism or Asperger syndrome. Data were coded and analysed using an inductive, qualitative thematic analysis. Four main themes encompassing both positive and negative sensory experiences emerged from these data: (a) the importance of particular aspects of stimuli in their perception, (b) the importance of having control over stimuli, (c) how emotions/mental states could impact/be impacted by sensory stimuli, and (d) physical responses to stimuli. These data are discussed alongside extant literature. Limitations, possible implications, and potential directions of future research are also discussed. PMID:26422904

  11. [Optical multi-channel detection and analysis on solar ultra-violet irradiance spectrum].

    PubMed

    Zhao, Xiao-yan; He, Jie; Zuo, Hao-yi; Liang, Hui-min; Yang, Jing-guo

    2007-05-01

    The present paper reports a new type of ultraviolet CCD optical multi-channel analyzer and its application to detecting solar ultraviolet irradiance spectrum. Spectral detecting range of 200-1 100 nm, spectral resolution of 0.1 nm and detecting sensitivity of 0.02 lx were reached in this instrument. The solar spectra of UVB and UVA were measured in real time in Chengdu area. The measurement results have good correlation with the detection using normal solar ultraviolet irradiance detector. Primary analysis on the detection results of solar spectra in UVB and UVA indicated that in the morning and in the afternoon the irradiance of solar ultraviolet is smaller than that at noon, and reverse correlation holds for the change of SZA (Solar Zenith Angle). In different wavelength interval of UVA and UVB, generally, the radiation flux of long wavelength is greater than that of short. Clouds and aerosols in the atmosphere have important influence on ultraviolet irradiance.

  12. Time evolution of surface chlorophyll patterns from cross-spectrum analysis of satellite color images

    NASA Technical Reports Server (NTRS)

    Denman, Kenneth L.; Abbott, Mark R.

    1988-01-01

    The rate of decorrelation of surface chlorophyll patterns as a function of the time separation between pairs of images was determined from two sequences of CZCS images of the Pacific Ocean area adjacent to Vancouver Island, Canada; cloud-free subareas were selected that were common to several images separated in time by 1-17 days. Image pairs were subjected to two-dimensional autospectrum and cross-spectrum analysis in an array processor, and squared coherence estimates found for several wave bands were plotted against time separation, in analogy with a time-lagged cross correlation function. It was found that, for wavelengths of 50-150 km, significant coherence was lost after 7-10 days, while for wavelengths of 25-50 km, significant coherence was lost after only 5-7 days. In both cases, offshore regions maintained coherence longer than coastal regions.

  13. Singular Spectrum Analysis for Astronomical Time Series: Constructing a Parsimonious Hypothesis Test

    NASA Astrophysics Data System (ADS)

    Greco, G.; Kondrashov, D.; Kobayashi, S.; Ghil, M.; Branchesi, M.; Guidorzi, C.; Stratta, G.; Ciszak, M.; Marino, F.; Ortolan, A.

    We present a data-adaptive spectral method - Monte Carlo Singular Spectrum Analysis (MC-SSA) - and its modification to tackle astrophysical problems. Through numerical simulations we show the ability of the MC-SSA in dealing with 1/f β power-law noise affected by photon counting statistics. Such noise process is simulated by a first-order autoregressive, AR(1) process corrupted by intrinsic Poisson noise. In doing so, we statistically estimate a basic stochastic variation of the source and the corresponding fluctuations due to the quantum nature of light. In addition, MC-SSA test retains its effectiveness even when a significant percentage of the signal falls below a certain level of detection, e.g., caused by the instrument sensitivity. The parsimonious approach presented here may be broadly applied, from the search for extrasolar planets to the extraction of low-intensity coherent phenomena probably hidden in high energy transients.

  14. Antiepileptic medications in autism spectrum disorder: a systematic review and meta-analysis.

    PubMed

    Hirota, Tomoya; Veenstra-Vanderweele, Jeremy; Hollander, Eric; Kishi, Taro

    2014-04-01

    Electroencephalogram-recorded epileptiform activity is common in children with autism spectrum disorder (ASD), even without clinical seizures. A systematic literature search identified 7 randomized, placebo-controlled trials of antiepileptic drugs (AEDs) in ASD (total n = 171), including three of valproate, and one each of lamotrigine, levetiracetam, and topiramate. Meta-analysis revealed no significant difference between medication and placebo in four studies targeting irritability/agitation and three studies investigating global improvement, although limitations include lack of power and different medications with diverse actions. Across all seven studies, there was no significant difference in discontinuation rate between two groups. AEDs do not appear to have a large effect size to treat behavioral symptoms in ASD, but further research is needed, particularly in the subgroup of patients with epileptiform abnormalities. PMID:24077782

  15. Quantifying Narrative Ability in Autism Spectrum Disorder: A Computational Linguistic Analysis of Narrative Coherence

    PubMed Central

    Losh, Molly; Gordon, Peter C.

    2014-01-01

    Autism Spectrum Disorder (ASD) is characterized by difficulties with social communication and functioning, and ritualistic/repetitive behaviors (American Psychiatric Association, 2013). While substantial heterogeneity exists in symptom expression, impairments in language discourse skills, including narrative, are universally observed (Tager-Flusberg, Paul, & Lord, 2005). This study applied a computational linguistic tool, Latent Semantic Analysis (LSA), to objectively characterize narrative performance in ASD across two narrative contexts differing in interpersonal and cognitive demands. Results indicated that individuals with ASD produced narratives comparable in semantic content to those from controls when narrating from a picture book, but produced narratives diminished in semantic quality in a more demanding narrative recall task. Results are discussed in terms of the utility of LSA as a quantitative, objective, and efficient measure of narrative ability. PMID:24915929

  16. [Optical multi-channel detection and analysis on solar ultra-violet irradiance spectrum].

    PubMed

    Zhao, Xiao-yan; He, Jie; Zuo, Hao-yi; Liang, Hui-min; Yang, Jing-guo

    2007-05-01

    The present paper reports a new type of ultraviolet CCD optical multi-channel analyzer and its application to detecting solar ultraviolet irradiance spectrum. Spectral detecting range of 200-1 100 nm, spectral resolution of 0.1 nm and detecting sensitivity of 0.02 lx were reached in this instrument. The solar spectra of UVB and UVA were measured in real time in Chengdu area. The measurement results have good correlation with the detection using normal solar ultraviolet irradiance detector. Primary analysis on the detection results of solar spectra in UVB and UVA indicated that in the morning and in the afternoon the irradiance of solar ultraviolet is smaller than that at noon, and reverse correlation holds for the change of SZA (Solar Zenith Angle). In different wavelength interval of UVA and UVB, generally, the radiation flux of long wavelength is greater than that of short. Clouds and aerosols in the atmosphere have important influence on ultraviolet irradiance. PMID:17655086

  17. Analysis of the Zeeman effect on the energy spectrum in graphenes

    SciTech Connect

    Feng, Sze-Shiang; Mochena, Mogus

    2011-08-15

    An analysis of the Zeeman effect with a strong external magnetic field on the energy spectrum in graphene is presented. In general, the Hamiltonian of graphene in applied electric and magnetic fields is not of SO(1, 2) invariance even in the nearest-neighbor approximation because of the Zeeman coupling. But an approximate SO(1, 2) invariance can be obtained when the applied magnetic field is very strong. This approximate invariance can be used to relate the energy structure of graphene in the presence of both electric and magnetic fields to that when there is only magnetic field. Therefore, it can help explain the recently found quantum Hall conductance (4q{sup 2}/h)L for L = 0.1.

  18. Compact range reflector analysis using the plane wave spectrum approach with an adjustable sampling rate

    NASA Astrophysics Data System (ADS)

    McKay, James P.; Rahmat-Samii, Yahya

    1991-06-01

    An improved method for determining the test zone field of compact range reflectors is presented. The plane wave spectrum (PWS) approach is used to obtain the test zone field from knowledge of the reflector aperture field distribution. The method is particularly well suited to the analysis of reflectors with a linearly serrated rim for reduced edge diffraction. Computation of the PWS of the reflector aperture field is facilitated by a closed-form expression for the Fourier transform of a polygonal window function. Inverse transformation in the test zone region is accomplished using a fast Fourier transform (FFT) algorithm with a properly adjusted sampling rate (which is a function of both the reflector size and the distance from the reflector). The method is validated by comparison with results obtained using surface current and aperture field integration techniques. The performance of several serrated reflectors is evaluated in order to observe the effects of edge diffraction on the test zone fields.

  19. Sensitivity Analysis Applied to Atomic Data Used for X-ray Spectrum Synthesis

    NASA Technical Reports Server (NTRS)

    Kallman, T.

    2006-01-01

    A great deal of work has been devoted to the accumulation of accurate quantities describing atomic processes for use in analysis of astrophysical spectra. But in many situations of interest the interpretation of a quantity which is observed, such as a line flux, depends on the results of a modeling- or spectrum synthesis code. The results of such a code depends in turn on many atomic rates or cross sections, and the sensitivity of the observable quantity on the various rates and cross sections may be non-linear and if so cannot easily be derived analytically. This paper describes simple numerical experiments designed to examine some of these issues. Similar studies have been carried out previously in the context of solar UV lines by Gianetti et al. (2000); Savin & Laming (2002) and in the context of the iron M shell UTA in NGC 3783 by Netzer (2004).

  20. FUNCTIONAL ANALYSIS AND TREATMENT OF ARRANGING AND ORDERING BY INDIVIDUALS WITH AN AUTISM SPECTRUM DISORDER

    PubMed Central

    Rodriguez, Nicole M; Thompson, Rachel H; Schlichenmeyer, Kevin; Stocco, Corey S

    2012-01-01

    Of the diagnostic features of autism, relatively little research has been devoted to restricted and repetitive behavior, particularly topographically complex forms of restricted and repetitive behavior such as rigidity in routines or compulsive-like behavior (e.g., arranging objects in patterns or rows). Like vocal or motor stereotypy, topographically complex forms of restricted and repetitive behavior may be associated with negative outcomes such as interference with skill acquisition, negative social consequences, and severe problem behavior associated with interruption of restricted and repetitive behavior. In the present study, we extended functional analysis methodology to the assessment and treatment of arranging and ordering for 3 individuals with an autism spectrum disorder. For all 3 participants, arranging and ordering was found to be maintained by automatic reinforcement, and treatments based on function reduced arranging and ordering. PMID:22403446