Science.gov

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. Full-spectrum analysis of natural gamma-ray spectra.

    PubMed

    Hendriks, P H; Limburg, J; de Meijer, R J

    2001-01-01

    In this paper, a new system to measure natural gamma-radiation in situ will be presented. This system combines a high-efficiency BGO scintillation detector with full-spectrum data analysis (FSA). This technique uses the (nearly) full spectral shape and the so-called 'standard spectra' to calculate the activity concentrations of 40K, 232Th and 238U present in a geological matrix (sediment, rock, etc.). We describe the FSA and the determination of the standard spectra. Standard spectra are constructed for various geometries and a comparison in intensity and shape will be made. The performance of such a system has been compared to a more traditional system, consisting of a NaI detector in combination with the 'windows' analysis. For count rates typically encountered in field experiments, the same accuracy is obtained 10-20 times faster using the new system. This allows for shorter integration times and hence shorter measurements or a better spatial resolution. The applicability of such a system will be illustrated via an example of an airborne experiment in which the new system produced results comparable to those of much larger traditional systems. This paper will conclude with a discussion of the current status of the system and an outlook for future research.

  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. 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.

  7. 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.

  8. Gamma-ray Full Spectrum Analysis for Environmental Radioactivity by HPGe Detector

    NASA Astrophysics Data System (ADS)

    Jeong, Meeyoung; Lee, Kyeong Beom; Kim, Kyeong Ja; Lee, Min-Kie; Han, Ju-Bong

    2014-12-01

    Odyssey, one of the NASA¡¯s Mars exploration program and SELENE (Kaguya), a Japanese lunar orbiting spacecraft have a payload of Gamma-Ray Spectrometer (GRS) for analyzing radioactive chemical elements of the atmosphere and the surface. In these days, gamma-ray spectroscopy with a High-Purity Germanium (HPGe) detector has been widely used for the activity measurements of natural radionuclides contained in the soil of the Earth. The energy spectra obtained by the HPGe detectors have been generally analyzed by means of the Window Analysis (WA) method. In this method, activity concentrations are determined by using the net counts of energy window around individual peaks. Meanwhile, an alternative method, the so-called Full Spectrum Analysis (FSA) method uses count numbers not only from full-absorption peaks but from the contributions of Compton scattering due to gamma-rays. Consequently, while it takes a substantial time to obtain a statistically significant result in the WA method, the FSA method requires a much shorter time to reach the same level of the statistical significance. This study shows the validation results of FSA method. We have compared the concentration of radioactivity of 40K, 232Th and 238U in the soil measured by the WA method and the FSA method, respectively. The gamma-ray spectrum of reference materials (RGU and RGTh, KCl) and soil samples were measured by the 120% HPGe detector with cosmic muon veto detector. According to the comparison result of activity concentrations between the FSA and the WA, we could conclude that FSA method is validated against the WA method. This study implies that the FSA method can be used in a harsh measurement environment, such as the gamma-ray measurement in the Moon, in which the level of statistical significance is usually required in a much shorter data acquisition time than the WA method.

  9. Spectrum Roentgen Gamma

    NASA Astrophysics Data System (ADS)

    Predehl, P.; Pavlinsky, M.

    2014-07-01

    Spectrum Roentgen Gamma (SRG) is an X-ray astrophysical observatory, developed by Russia in collaboration with Germany. The mission will be launched in 2016 into a 6-month-period halo orbit around L2. The mission lifetime is planned to be more than seven years. While the first four years of the mission are devoted to an all sky survey, the rest of the mssion will be used for pointed observations. The payload consists of two X-ray telescopes, eROSITA and ART-XC. The eROSITA sky survey will be about 30 times more sensitive than ROSAT at energies between 0.5 and 2 keV, while in the hard band (2-8 keV) it will provide the first ever true imaging survey of the sky. The design driving science is the detection of large samples of galaxy clusters out to redshifts z>1 in order to study the large scale structure in the universe and test cosmological models including Dark Energy. ART-XC's role is to extend the energy range of eROSITA alone, thereby doubling the effective area in the critical 4-7 keV range. The harder response of ART-XC also facilitates the x-ray detection of obscured AGN. Both instruments are currently in the flight model and calibration phase.

  10. 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.

  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. Does the Blazar Gamma-ray Spectrum Harden with Increasing Flux? - Analysis of Nine Years of EGRET Data

    NASA Technical Reports Server (NTRS)

    Nandikotkur, Giridhar; Jahoda, Keith M.; Hartman, R. C.; Mukherjee, R.; Sreekumar, P.; Boettcher, M.

    2007-01-01

    The Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO) discovered gamma-ray emission from more than 67 blazars during its nine-year lifetime. We conducted an exhaustive search of the EGRET archives and selected all the blazars that were observed multiple times and were bright enough to enable a spectral analysis using standard powerlaw models. The sample consists of 18 flat-spectrum radio quasars (FSRQs), 6 low-frequency-peaked BL Lacs (LBLs) and 2 high-frequency-peaked BL Lacs (HBLs). We do not detect any clear pattern in'the variation of spectral index with flux. Some of the blazars do not show any statistical evidence for spectral variability. The spectrum hardens with increasing flux in a few cases. There is also evidence for a flux-hardness anticorrelation at lo\\v fluxes in five blazars. The well observed blazars (3C 279,3C 273, PKS 0528-i-134, PKS 1622-297, PKS 0208- 512) do not show any overall trend in the long-term spectral dependence on flux, but the sample shows a mixture of hard and soft states. We observed spectral hysteresis at weekly timescales in all the three FSRQs for which data from flares lasting for 3 approx. 4 weeks were available. All three sources show a counterclockwise rotation despite the widely different flux profiles. Hysteresis in the spectral index vs. flux space has never been observed in FSRQs in gamma-rays at weekly timescales. itre analyze the observed spectral behavior in the context of various inverse-Compton mechanisms believed to be responsible for emission in the EGRET energy range. Our analysis uses the EGRET skymaps that were regenerated to include the changes in performance during the mission.

  13. MGA (Multi-Group Analysis): A gamma-ray spectrum analysis code for determining plutonium isotopic abundances

    SciTech Connect

    Gunnink, R

    1990-04-03

    Nondestructive measurements of x-ray and gamma-ray emissions can be used to analyze a sample for plutonium. This report describes the methods and algorithms we have developed for analyzing gamma-ray spectra obtained by using a germanium detector system to accurately determine the relative abundances of various actinide isotopes in a sample. Our methodology requires no calibrations and can be used to measure virtually any size and type of plutonium sample. Measurement times can be as short as a few minutes; measurements are frequently accurate to within 1%. Our methods have been programmed into a computerized analysis code called MGA (Multi-Group Analysis). Our current versions can be run on personal computers (IBM type) and on the DEC VAX microcomputer. Spectral analysis times are usually far less than a minute. 28 refs., 26 figs., 1 tab.

  14. 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.

  15. 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…

  16. The energy spectrum for stochastic eddies with gamma distribution

    NASA Astrophysics Data System (ADS)

    Kara, Rukiye; Caglar, Mine

    2012-09-01

    Lundgren (1982) showed that strained spiral vortex model for turbulent fine structure has exponential Kolmogorov energy spectrum form. Caglar (2007) has generalized Cinlar velocity field which defined a similar structure with Lundgren vortex and computed the energy spectrum. In this study, we investigate the energy spectrum of the stochastic velocity field using Gamma distribution for small scale eddies.

  17. Atypical laterality of resting gamma oscillations in autism spectrum disorders.

    PubMed

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

    2015-02-01

    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 and intelligence quotient matched typically developing controls. We found a decrease in resting gamma power at right lateral electrodes in ASD. We further explored associations between gamma and ASD severity as measured by the Social Responsiveness Scale (SRS) and found a negative correlation between SRS and gamma power. We believe that our findings give further support of gamma oscillations as a potential biomarker for ASD.

  18. Dynamic spectrum of airborne gamma-rays.

    PubMed

    Minato, S

    1990-04-01

    This note describes a method of direct measurement of airborne gamma-rays primarily from 222Rn daughters using a NaI(Tl) scintillation spectrometer with lead shields. This method has the advantage of being able to maintain the system easily compared to other usual systems including a pump. The pulse-height distributions are successively fed to a floppy disk in a personal computer every unit time. The gain shifts can be corrected automatically by a computer program. This technique would be applicable to the estimation of 222Rn daughters concentration and to examination of disequilibrium between 214Pb(RaB) and 214Bi(RaC) and of those height distribution up to about 200 m. The accuracy for estimating the concentration is as good as that of the filter method.

  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. 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.

  1. Spectrum-Roentgen-Gamma astrophysical mission

    NASA Astrophysics Data System (ADS)

    Pavlinsky, M.; Sunyaev, R.; Churazov, E.; Gilfanov, M.; Vikhlinin, A.; Hasinger, G.; Predehl, P.; Mitsuda, K.; Kelley, R.; McCammon, D.; Ohashi, T.; den Herder, J. W.; Ramsey, B.; Gubarev, M.; O'Dell, S.; Fujimoto, R.

    2008-07-01

    The Spectrum-RG (SRG) mission, to be launched in 2011, will conduct the first all-sky survey in the 0.1-15 keV band via two imaging telescope systems, eROSITA and ART-XC. These will enable the detection of about 100 thousand clusters of galaxies and the mapping of the large scale structure of the Universe. They will also discover all obscured accreting Black Holes in nearby galaxies and about >=3 million new, distant AGNs. In the course of the survey mode two sky regions around the celestial polar zones will be observed with much higher sensitivity. Then, selected sources and dedicated sky regions will be observed in a pointing mode with high sensitivity in order to investigate the nature of dark matter and dark energy. An X-Ray Calorimeter, the SXC experiment, will permit observations of the brightest clusters of galaxies with record energy resolution in pointing mode and mapping of the hot intergalactic medium in the survey mode.

  2. 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.

  3. Gamma ray cosmology: The extra galactic gamma spectrum and methods to detect the underlying source

    NASA Technical Reports Server (NTRS)

    Cline, David B.

    1990-01-01

    The possible sources of extragalactic gamma rays and methods to distinguish the different sources are discussed. The sources considered are early universe decays and annihilation of Particles, active galactic nuclei (AGN) sources, and baryon-antibaryon annihilation in a baryon symmetric cosmology. The energy spectrum and possible angular fluctuations due to these sources are described.

  4. A COMPREHENSIVE ANALYSIS OF FERMI GAMMA-RAY BURST DATA. II. E{sub p} EVOLUTION PATTERNS AND IMPLICATIONS FOR THE OBSERVED SPECTRUM-LUMINOSITY RELATIONS

    SciTech Connect

    Lu Ruijing; Wei Junjie; Liang Enwei; Lue Lianzhong; Zhang Binbin; Lue Houjun; Zhang Bing; Lei Weihua E-mail: zhang@physics.unlv.edu

    2012-09-10

    We present a time-resolved spectral analysis of 51 long and 11 short bright gamma-ray bursts (GRBs) observed with the Fermi/Gamma-Ray Burst Monitor, paying special attention to E{sub p} evolution within each burst. Among eight single-pulse long GRBs, five show an evolution from hard to soft, while three show intensity tracking. The multi-pulse long GRBs have more complicated patterns. Statistically, the hard-to-soft evolution pulses tend to be more asymmetric than the intensity-tracking ones, with a steeper rising wing than the falling wing. Short GRBs have E{sub p} tracking intensity exclusively with the 16 ms time-resolution analysis. We performed a simulation analysis and suggest that for at least some bursts, the late intensity-tracking pulses could be a consequence of overlapping hard-to-soft pulses. However, the fact that the intensity-tracking pattern exists in the first pulse of the multi-pulse long GRBs and some single-pulse GRBs, suggests that intensity tracking is an independent component, which may operate in some late pulses as well. For the GRBs with measured redshifts, we present a time-resolved E{sub p} - L{sub {gamma},iso} correlation analysis and show that the scatter of the correlation is comparable to that of the global Amati/Yonetoku relation. We discuss the predictions of various radiation models regarding E{sub p} evolution, as well as the possibility of a precessing jet in GRBs. The data pose a great challenge to each of these models, and hold the key to unveiling the physics behind GRB prompt emission.

  5. 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.

  6. 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.

  7. EGRET/COMPTEL Observations of an Unusual, Steep-Spectrum Gamma-Ray Source

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.; Bertsch, D. L.; Hartman, R. C.; Collmar, W.; Johnson, W. N.

    1999-01-01

    During analysis of sources below the threshold of the third EGRET catalog, we have discovered a source, named GRO J1400-3956 based on the best position, with a remarkably steep spectrum. Archival analysis of COMPTEL data shows that the spectrum must have a strong turn-over in the energy range between COMPTEL and EGRET. The EGRET data show some evidence of time variability, suggesting an AGN, but the spectral change of slope is larger than that seen for most gamma-ray blazars. The sharp cutoff resembles the high-energy spectral breaks seen in some gamma-ray pulsars. There have as yet been no OSSE observations of this source.

  8. On the omnipresent background gamma radiation of the continuous spectrum

    NASA Astrophysics Data System (ADS)

    Banjanac, R.; Maletić, D.; Joković, D.; Veselinović, N.; Dragić, A.; Udovičić, V.; Aničin, I.

    2014-05-01

    The background spectrum of a germanium detector, shielded from the radiations arriving from the lower and open for the radiations arriving from the upper hemisphere, is studied by means of absorption measurements, both in a ground level and in an underground laboratory. The low-energy continuous portion of this background spectrum that peaks at around 100 keV, which is its most intense component, is found to be of very similar shape at the two locations. It is established that it is mostly due to the radiations of the real continuous spectrum, which is quite similar to the instrumental one. The intensity of this radiation is in our cases estimated to about 8000 photons/(m2s·2π·srad) in the ground level laboratory, and to about 5000 photons/(m2s·2π·srad) in the underground laboratory, at the depth of 25 m.w.e. Simulations by GEANT4 and CORSIKA demonstrate that this radiation is predominantly of terrestrial origin, due to environmental gamma radiations scattered off the materials that surround the detector (the "skyshine radiation"), and to a far less extent to cosmic rays of degraded energy.

  9. 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.

  10. Interstellar absorption lines in the spectrum of Gamma Velorum

    NASA Technical Reports Server (NTRS)

    Morton, D. C.; Bhavsar, S. P.

    1979-01-01

    Copernicus scans of selected interstellar absorption lines in the UV spectrum of Gamma Vel are analyzed, together with ground-based data, to obtain column densities for various ion states of C, N, O, Na, Mg, Al, Si, P, S, Cl, Ar, Ca, Mn, Fe, and CO. N I and O I are fitted to a single empirical curve of growth with a velocity parameter (b) of 8 km/s; Mg II, Si II, P II, S II, Mn II, and Fe II are fitted to another curve with b between 3 and 9 km/s. Abundance determinations relative to H I show that: (1) C, N, P, S, and Ar are probably close to their solar values; (2) O may be depleted by about a factor of 2; (3) Mg, Al, Si, Cl, Mn, and Fe are depleted by a factor of 4 or more: (4) Al is depleted by at least a factor of 10 in the H II region; and (5) both N V and O VI are present, but not C IV. The N V/O VI ratio implies that the electron temperature in the H II region is about 275,000 K.

  11. Prompt-Gamma Activation Analysis.

    PubMed

    Lindstrom, Richard M

    1993-01-01

    A permanent, 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 this 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.

  12. Primary cosmic ray energy spectrum in terms of the GAMMA muon data

    NASA Astrophysics Data System (ADS)

    Garyaka, A. P.; Martirosov, R. M.; Ter-Antonyan, S. V.; Erlykin, A. D.; Nikolskaya, N. M.; Gallant, Y. A.; Jones, L. W.; Procureur, J.

    2009-12-01

    The energy spectrum of the primary cosmic rays is obtained by conversion from the truncated muon size spectrum of EAS studied with the GAMMA array. The previously observed dependence of E on Nμtr at various zenith angles is used. It is shown that the present spectrum has the same structure (“bump”) as the spectrum determined by another independent multi-parametric energy estimation method confirming that the “bump” structure is not produced by uncertainties in our methods.

  13. 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.

  14. Estimates of the DT Fusion Gamma Spectrum Using an Energy Thresholding Gas Cherenkov Detector

    NASA Astrophysics Data System (ADS)

    Horsfield, Colin; Rubery, Michael; Hans, Herrmann; Mack, Joseph; Young, Carl; Caldwell, Steven; Scott, Evans; Sedillo, Thomas; Kim, Yongho; Hale, Gerry; Shah, Rahul; Kirk, Miller; Wolfgang, Stoefll

    2011-10-01

    In addition to alphas and neutrons, the DT fusion reaction also produces gamma rays from the intermediate excited 5He nucleus with a small branching ratio 10E-5 gamma/n. The very small branching ratio of the gamma-rays are mitigated by the very large yields that are expected on NIF (10E+19). The excited 5He can produce gamma-rays by decay to the ground state, emitting a 16.75 MeV gamma-ray (width 0.5 MeV), or to a broad first excited state emitting a 12 MeV gamma ray (width 5 MeV). Knowledge of the relative gamma-ray BR of these two states, from which we infer the DT gamma ray spectrum, is important to making absolutely calibrated measurements on a variety of experiments. We have carried out an energy thresh-holding experiment for DT ICF implosions on the Omega laser using a Gas Cherenkov Detector, and compared the relative intensities at various thresholds with theoretical gamma spectra folded with detector response as calculated by ACCEPT and GEANT4 codes. We present recent results from this experiment, our estimate of the precision of the DT fusion gamma spectrum and the implications for the future determination of the DT gamma/n BR.

  15. Hard-spectrum gamma-ray flare from PKS 0507+17

    NASA Astrophysics Data System (ADS)

    Kreter, M.; Buson, S.

    2016-11-01

    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 PKS 0507+17 (R.A.= 05h10m02.3691s, Dec.= +18d00m41.582s, J2000.0, Johnston et al. 1995, AJ, 110, 880).

  16. 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.

  17. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    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 51Cr is presented.

  19. 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.

  20. 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.

  1. 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.

  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. Fermi LAT Search for Dark Matter in Gamma-Ray Lines and the Inclusive Photon Spectrum

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Albert, A.; Baldini, L.; Barbiellini, G.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Brigida, M.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Charles, E.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Moiseev, Alexander A.

    2012-01-01

    Dark matter particle annihilation or decay can produce monochromatic gamma-ray lines and contribute to the diffuse gamma-ray background. Flux upper limits are presented for gamma-ray spectral lines from 7 to 200 GeV and for the diffuse gamma-ray background from 4.8 GeV to 264 GeV obtained from two years of Fermi Large Area Telescope data integrated over most of the sky. We give cross section upper limits and decay lifetime lower limits for dark matter models that produce gamma-ray lines or contribute to the diffuse spectrum, including models proposed as explanations of the PAMELA and Fermi cosmic-ray data.

  4. Spectrum of [gamma] rays connecting superdeformed and normal states in [sup 192]Hg

    SciTech Connect

    Henry, R.G.; Lauritsen, T.; Khoo, T.L.; Ahmad, I.; Carpenter, M.P.; Crowell, B.; Dossing, T.; Janssens, R.V.F.; Hannachi, F.; Korichi, A.; Schuck, C.; Azaiez, F.; Beausang, C.W.; Beraud, R.; Bourgeois, C.; Clark, R.M.; Deloncle, I.; Duprat, J.; Gall, B.; Hubel, H.; Joyce, M.J.; Kaci, M.; Lecoz, Y.; Meyer, M.; Paul, E.S.; Perrin, N.; Poffe, N.; Porquet, M.G.; Redon, N.; Sergolle, H.; Sharpey-Schafer, J.F.; Simpson, J.; Smith, A.G.; Wadsworth, R.; Willsau, P. Centre de Spectrometrie Nucleaire et de Spectrometrie, Institut National de Physique Nucleaire et de Physiques des Particules, Centre National de la Recherche Scientifique, F-91405 Orsay Institut de Physique Nucleaire, Institut National de Physique Nucleaire et de Physiques des Particules, Centre National de la Recherche Scientifique, F-91406 Orsay University of Liverpool, Liverpool L69 3BX Institut de Physique Nucleaire Lyon, I

    1994-08-08

    The complete spectrum of [gamma] rays following the decay of superdeformed (SD) states in [sup 192]Hg has been extracted. The spectrum, which comprises a quasicontinuous component and sharp lines, reveals the decay mechanism and defines the excitation energies of the SD band. The decay of SD states results from the coupling between a cold, ordered SD system with a hot, chaotic one with normal deformation.

  5. Fermi LAT Detection of a Hard Spectrum Gamma-ray Flare from the FSRQ S4 0954+65

    NASA Astrophysics Data System (ADS)

    Ojha, Roopesh; Carpenter, Bryce; Tanaka, Yasuyuki

    2015-02-01

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope has observed an unusually hard spectrum gamma-ray flare from the flat spectrum radio quasar (FSRQ) S4 0954+65 (3FGL J0958.6+6534; RA: 149.696855, Dec: +65.565227, J2000, Johnston et al. 1995, AJ, 110, 880).

  6. Gamma-ray spectrum of the galactic center region

    SciTech Connect

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

    1985-07-01

    The Galactic center region was observed with the HEAO 3 High Resolution Gamma-Ray Spectrometer during the fall of 1979 and the spring of 1980. Between these epochs we observed (1) a statistically significant decrease in the high-energy (511 keV to approx.3 MeV) luminosity (2) a decrease in the positron annihilation line intensity, reported previously, and (3) a low positronium annihilation fraction f = 0.38 +- 0.19 during the fall of 1979. If positrons are generated by photon-photon collisions of high-energy photons, then the absence of a detected flux above 511 keV in the spring of 1980 may indicate a time delay between positron production and annihilation.

  7. Progress report for the Monte-Carlo gamma-ray spectrum simulation program BSIMUL

    NASA Technical Reports Server (NTRS)

    Haywood, S. E.; Rester, A. C., Jr.

    1996-01-01

    The progress made during 1995 on the Monte-Carlo gamma-ray spectrum simulation program BSIMUL is discussed. Several features have been added, including the ability to model shields that are tapered cylinders. Several simulations were made on the Near Earth Asteroid Rendezvous detector.

  8. A measurement of the gamma-ray spectrum from the Crab Nebula

    NASA Astrophysics Data System (ADS)

    Lizarazo, Juan Fernando

    CACTUS is a ground-based Air Cherenkov Telescope located at the Solar 2 facility in the Southern California Mojave desert. It uses an array of 168 heliostats and a camera with 80 photomultiplier tubes to detect Cherenkov radiation produced by air showers. CACTUS incorporates fast electronics together with novel techniques of time projection imaging and pattern triggering, thus improving upon the first generation sampling ACTs. Multiplexing of PMTS and heliostats allow us to collect up to 300 independent samples of a Cherenkov light front-wave. With the capability of detecting gamma rays with energies from 50 GeV up, CACTUS is poised to provide insight into very exciting new physics. In particular, measuring the Crab nebula spectrum in the energy range between 20 to 200 GeV, will allow us to define an appropriate model for the Inverse Compton lump, together with constraints on model parameters. A full analysis of the data set collected during the winter of 2005 provided us with a Crab nebula spectrum that starts under 100 GeV and goes up to a few TeV. Implications of this will be talked about.

  9. Estimation of neutron spectrum in the low-level gamma spectroscopy system using unfolding procedure

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    The radiation resulting from neutron interactions with Ge nuclei in active volume of HPGe detectors is one of the main concerns in low-level gamma spectroscopy measurements [1,2]. It is usually not possible to measure directly spectrum of neutrons which strike detector. This paper explore the possibility of estimation of neutron spectrum using measured activities of certain Ge(n,γ) and Ge(n,n') reactions (obtained from low-level gamma measurements), available ENDF cross section data and unfolding procedures. In this work HPGe detector with passive shield made from commercial low background lead was used for the measurement. The most important objective of this study was to reconstruct muon induced neutron spectrum created in the shield of the HPGe detector. MAXED [3] and GRAVEL [4] algorithms for neutron spectra unfolding were used. The results of those two algorithms were compared and we analyzed the sensitivity of the unfolding procedure to the various input parameters.

  10. 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.

  11. 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.

  12. Reproducibility of (n,γ) gamma ray spectrum in Pb under different ENDF/B releases

    NASA Astrophysics Data System (ADS)

    Kebwaro, J. M.; He, C. H.; Zhao, Y. L.

    2016-04-01

    Radiative capture reactions are of interest in shielding design and other fundamental research. In this study the reproducibility of (n,γ) reactions in Pb when cross-section data from different ENDF/B releases are used in the Monte-Carlo code, MCNP, was investigated. Pb was selected for this study because it is widely used in shielding applications where capture reactions are likely to occur. Four different neutron spectra were declared as source in the MCNP model which consisted of a simple spherical geometry. The gamma ray spectra due to the capture reactions were recorded at 10 cm from the center of the sphere. The results reveal that the gamma ray spectrum produced by ENDF/B-V is in reasonable agreement with that produced when ENDF/B-VI.6 is used. However the spectrum produced by ENDF/B-VII does not reveal any primary gamma rays in the higher energy region (E > 3 MeV). It is further observed that the intensities of the capture gamma rays produced when various releases are used differ by a some margin showing that the results are not reproducible. The generated spectra also vary with the spectrum of the source neutrons. The discrepancies observed among various ENDF/B releases could raise concerns to end users and need to be addressed properly during benchmarking calculations before the next release. The evaluation from ENDF to ACE format that is supplied with MCNP should also be examined because errors might have arisen during the evaluation.

  13. Injection Locking Techniques for Spectrum Analysis

    NASA Astrophysics Data System (ADS)

    Gathma, Timothy D.; Buckwalter, James F.

    2011-04-01

    Wideband spectrum analysis supports future communication systems that reconfigure and adapt to the capacity of the spectral environment. While test equipment manufacturers offer wideband spectrum analyzers with excellent sensitivity and resolution, these spectrum analyzers typically cannot offer acceptable size, weight, and power (SWAP). CMOS integrated circuits offer the potential to fully integrate spectrum analysis capability with analog front-end circuitry and digital signal processing on a single chip. Unfortunately, CMOS lacks high-Q passives and wideband resonator tunability that is necessary for heterodyne implementations of spectrum analyzers. As an alternative to the heterodyne receiver architectures, two nonlinear methods for performing wideband, low-power spectrum analysis are presented. The first method involves injecting the spectrum of interest into an array of injection-locked oscillators. The second method employs the closed loop dynamics of both injection locking and phase locking to independently estimate the injected frequency and power.

  14. Injection Locking Techniques for Spectrum Analysis

    SciTech Connect

    Gathma, Timothy D.; Buckwalter, James F.

    2011-04-19

    Wideband spectrum analysis supports future communication systems that reconfigure and adapt to the capacity of the spectral environment. While test equipment manufacturers offer wideband spectrum analyzers with excellent sensitivity and resolution, these spectrum analyzers typically cannot offer acceptable size, weight, and power (SWAP). CMOS integrated circuits offer the potential to fully integrate spectrum analysis capability with analog front-end circuitry and digital signal processing on a single chip. Unfortunately, CMOS lacks high-Q passives and wideband resonator tunability that is necessary for heterodyne implementations of spectrum analyzers. As an alternative to the heterodyne receiver architectures, two nonlinear methods for performing wideband, low-power spectrum analysis are presented. The first method involves injecting the spectrum of interest into an array of injection-locked oscillators. The second method employs the closed loop dynamics of both injection locking and phase locking to independently estimate the injected frequency and power.

  15. 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.

  16. 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.

  17. Multivariate analysis of gamma spectra to characterize used nuclear fuel

    NASA Astrophysics Data System (ADS)

    Coble, Jamie; Orton, Christopher; Schwantes, Jon

    2017-04-01

    The Multi-Isotope Process (MIP) Monitor provides an efficient means to monitor the process conditions in used nuclear fuel reprocessing facilities to support process verification and validation. The MIP Monitor applies multivariate analysis to gamma spectroscopy of key stages in the reprocessing stream in order to detect small changes in the gamma spectrum, which may indicate changes in process conditions. This research extends the MIP Monitor by characterizing a used fuel sample after initial dissolution according to the type of reactor of origin (pressurized or boiling water reactor; PWR and BWR, respectively), initial enrichment, burn up, and cooling time. Simulated gamma spectra were used to develop and test three fuel characterization algorithms. The classification and estimation models employed are based on the partial least squares regression (PLS) algorithm. A PLS discriminate analysis model was developed which perfectly classified reactor type for the three PWR and three BWR reactor designs studied. Locally weighted PLS models were fitted on-the-fly to estimate the remaining fuel characteristics. For the simulated gamma spectra considered, burn up was predicted with 0.1% root mean squared percent error (RMSPE) and both cooling time and initial enrichment with approximately 2% RMSPE. This approach to automated fuel characterization can be used to independently verify operator declarations of used fuel characteristics and to inform the MIP Monitor anomaly detection routines at later stages of the fuel reprocessing stream to improve sensitivity to changes in operational parameters that may indicate issues with operational control or malicious activities.

  18. 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.

  19. 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.

  20. 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...

  1. 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.

  2. 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.

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

    SciTech Connect

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

    2016-01-22

    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.

  4. 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).

  5. 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.

  6. 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.

  7. Experiences with area specific spectrum stripping of NaI(Tl) gamma spectra.

    PubMed

    Aage, H K; Korsbech, U; Bargholz, K; Bystöm, S; Wedmark, M; Thorshaug, S

    2006-01-01

    Processing of airborne and carborne gamma-ray spectra (AGS and CGS) often includes the stripping (elimination) of the signals from natural radioactivity. Hereby the net result becomes the signals from man-made radioactivity or other radiation anomalies. The parameters needed for spectrum stripping are dependent on detector size and quality as well as on the energy windows. In addition they depend on the environmental geometry including the vehicle carrying the detector. For AGS the altitude also influences the parameters. In general the stripping parameters are determined from tedious laboratory or field measurements with known sources of natural radioactivity. Stripping parameters may, however, often be calculated from the actual survey data or from data from a similar area. Both post-processing and real-time processing are possible. The technique is useful for gamma source search, for detection of radiation anomalies and for mapping of contamination levels. The use of the technique is illustrated with field exercise data.

  8. 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.

  9. 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.

  10. 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.

  11. Very high energy gamma-rays from flat spectrum radio quasars

    NASA Astrophysics Data System (ADS)

    Lindfors, Elina

    2015-03-01

    The detection of Flat Spectrum Radio Quasars (FSRQs) in the Very High Energy (VHE, E>100 GeV) range is challenging, mainly because of their steep soft spectra and distance. Nevertheless four FSRQs are now known to be VHE emitters. The detection of the VHE γ-rays has challenged the emission models of these sources. The sources are also found to exhibit very different behavior. I will give an overview of what is known about the VHE emission of these sources and about the multiwavelength signatures that are connected to the VHE gamma-ray emission.

  12. Status of the Stellar X-Ray Polarimeter for the Spectrum-X-Gamma mission

    NASA Technical Reports Server (NTRS)

    Kaaret, P.; Novick, R.; Shaw, P.; Hanany, S.; Liu, Y.; Fleischman, J. R.; Siuniaev, R.; Lapshov, I.; Weisskopf, M. C.; Elsner, R. F.

    1991-01-01

    The Stellar X-Ray Polarimeter (SXRP) uses the polarization sensitivity of a graphite Bragg crystal and a lithium Thomsom scattering target to measure the polarization of X-rays from astrophysical sources. The SXRP is a focal plane detector for the Soviet-Danish SODART telescopes which will be launched on the Soviet Spectrum-X-Gamma mission. The SXRP will be the third orbiting stellar X-ray polarimeter, and should provide an order of magnitude increase in polarization sensitivity over its predecessors.

  13. 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.

  14. Extragalactic gamma-ray signal from dark matter annihilation: a power spectrum based computation

    NASA Astrophysics Data System (ADS)

    Serpico, P. D.; Sefusatti, E.; Gustafsson, M.; Zaharijas, G.

    2012-03-01

    We revisit the computation of the extragalactic gamma-ray signal from cosmological dark matter annihilations. The prediction of this signal is notoriously model-dependent, due to different descriptions of the clumpiness of the dark matter distribution at small scales, responsible for an enhancement with respect to the smoothly distributed case. We show how a direct computation of this 'flux multiplier' in terms of the non-linear power spectrum offers a conceptually simpler approach and may ease some problems, such as the extrapolation issue. In fact, very simple analytical recipes to construct the power spectrum yield results similar to the popular Halo Model expectations, with a straightforward alternative estimate of errors. For this specific application, one also obviates the need of identifying (often literature-dependent) concepts entering the Halo Model, to compare different simulations.

  15. 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.

  16. Derivative based sensitivity analysis of gamma index

    PubMed Central

    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

  17. 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.

  18. A new code for spectrometric analysis for environmental radiological surveillance on monitors focused on gamma radioactivity on aerosols

    SciTech Connect

    De Blas, Alfredo; Tapia, Carlos; Riego, Albert; Garcia, Roger; Dies, Javier; Diaz, Pedro; Toral, Juan; Batalla, Enric

    2015-07-01

    pGamma is a code developed by the NERG group of the Technical University of Catalonia - Barcelona Tech for the analysis of gamma spectra generated by the Equipment for the Continuous Measurement and Identification of Gamma Radioactivity on Aerosols with Paper Filter developed for our group and Raditel Servies company. Nowadays the code is in the process of adaptation for the monitors of the Environmental Radiological Surveillance Network of the Local Government of Catalonia (Generalitat of Catalonia), Spain. The code is a Spectrum Analysis System, it identifies the gamma emitters on the spectrum, determines its Concentration of Activity, generates alarms depending on the Activity of the emitters and generates a report. The Spectrum Analysis System includes a library with emitters of interest, NORM and artificial. The code is being used on the three stations with the aerosol monitor of the Network (Asco and Vandellos, near both Nuclear Power Plants and Barcelona). (authors)

  19. GammaLib: A New Framework for the Analysis of Astronomical Gamma-Ray Data

    NASA Astrophysics Data System (ADS)

    Knödlseder, J.

    2012-09-01

    With the advent of a new generation of telescopes (INTEGRAL, Fermi, H.E.S.S., MAGIC, VERITAS, MILAGRO) and the prospects of planned observatories such as CTA or HAWC, gamma-ray astronomy is becoming an integral part of modern astrophysical research. Analysing gamma-ray data is still a major challenge, and today relies on a large diversity of tools and software frameworks that were specifically developed for each instrument. With the goal of facilitating and unifying the analysis of gamma-ray data, we are currently developing an innovative data analysis toolbox, called the GammaLib, that enables gamma-ray data analysis in an instrument independent way. We will present the basic ideas that are behind the GammaLib, and describe its architecture and usage.

  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 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.

  1. Monte Carlo models and analysis of galactic disk gamma-ray burst distributions

    NASA Technical Reports Server (NTRS)

    Hakkila, Jon

    1989-01-01

    Gamma-ray bursts are transient astronomical phenomena which have no quiescent counterparts in any region of the electromagnetic spectrum. Although temporal and spectral properties indicate that these events are likely energetic, their unknown spatial distribution complicates astrophysical interpretation. Monte Carlo samples of gamma-ray burst sources are created which belong to Galactic disk populations. Spatial analysis techniques are used to compare these samples to the observed distribution. From this, both quantitative and qualitative conclusions are drawn concerning allowed luminosity and spatial distributions of the actual sample. Although the Burst and Transient Source Experiment (BATSE) experiment on Gamma Ray Observatory (GRO) will significantly improve knowledge of the gamma-ray burst source spatial characteristics within only a few months of launch, the analysis techniques described herein will not be superceded. Rather, they may be used with BATSE results to obtain detailed information about both the luminosity and spatial distributions of the sources.

  2. Quantitative comparison of 3D and 2.5D gamma analysis: introducing gamma angle histograms

    NASA Astrophysics Data System (ADS)

    Sa'd, M. Al; Graham, J.; Liney, G. P.; Moore, C. J.

    2013-04-01

    Comparison of dose distributions using the 3D gamma method is anticipated to provide better indicators for the quality assurance process than the 2.5D (stacked 2D slice-by-slice) gamma calculation, especially for advanced radiotherapy technologies. This study compares the accuracy of the 3D and 2.5D gamma calculation methods. 3D and 2.5D gamma calculations were carried out on four reference/evaluation 3D dose sample pairs. A number of analysis methods were used, including average gamma and gamma volume histograms. We introduce the concept of gamma-angle histograms. Noise sensitivity tests were also performed using two different noise models. The advantage of the 3D gamma method showed up as a higher proportion of points passing the tolerance criteria of 3% dose difference and 3 mm distance-to-agreement (DTA), with considerably lower average gamma values, a lower influence of the DTA criterion, and a higher noise tolerance. The 3D gamma approach is more reliable than the 2.5D approach in terms of providing comprehensive quantitative results, which are needed in quality assurance procedures for advanced radiotherapy methods.

  3. Angular spectrum analysis in heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Llanes-Estrada, Felipe J.; Muñoz Martínez, Jose L.

    2017-01-01

    Heavy Ion Collisions serve to study some features of early-universe cosmology. In this contribution we adapt data analysis frequently used to understand the Cosmic Microwave Background anisotropies (such as the Mollweide projection and the angular power spectrum) to heavy ion collisions at the LHC. We examine a few publicly available events of the ALICE collaboration under this light. Because the ALICE time projection chamber has limited coverage in rapidity and some blind angles in the transverse plane, the angular spectrum seems very influenced by the detector's acceptance.

  4. 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.

  5. Multivariate analysis of gamma spectra to characterize used nuclear fuel

    DOE PAGES

    Coble, Jamie; Orton, Christopher; Schwantes, Jon

    2017-01-17

    The Multi-Isotope Process (MIP) Monitor provides an efficient means to monitor the process conditions in used nuclear fuel reprocessing facilities to support process verification and validation. The MIP Monitor applies multivariate analysis to gamma spectroscopy of key stages in the reprocessing stream in order to detect small changes in the gamma spectrum, which may indicate changes in process conditions. This research extends the MIP Monitor by characterizing a used fuel sample after initial dissolution according to the type of reactor of origin (pressurized or boiling water reactor; PWR and BWR, respectively), initial enrichment, burn up, and cooling time. Simulated gammamore » spectra were used in this paper to develop and test three fuel characterization algorithms. The classification and estimation models employed are based on the partial least squares regression (PLS) algorithm. A PLS discriminate analysis model was developed which perfectly classified reactor type for the three PWR and three BWR reactor designs studied. Locally weighted PLS models were fitted on-the-fly to estimate the remaining fuel characteristics. For the simulated gamma spectra considered, burn up was predicted with 0.1% root mean squared percent error (RMSPE) and both cooling time and initial enrichment with approximately 2% RMSPE. Finally, this approach to automated fuel characterization can be used to independently verify operator declarations of used fuel characteristics and to inform the MIP Monitor anomaly detection routines at later stages of the fuel reprocessing stream to improve sensitivity to changes in operational parameters that may indicate issues with operational control or malicious activities.« less

  6. Gamma Detector Response and Analysis Software - Light

    SciTech Connect

    Mitchell, Dean J.

    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 incorporates 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.

  7. A HIGH SIGNAL-TO-NOISE RATIO COMPOSITE SPECTRUM OF GAMMA-RAY BURST AFTERGLOWS

    SciTech Connect

    Christensen, L.; Fynbo, J. P. U.; Prochaska, J. X.; Jakobsson, P.

    2011-02-01

    We present a composite spectrum of 60 long duration gamma-ray burst (GRB) afterglows with redshifts in the range 0.35 < z < 6.7 observed with low-resolution optical spectra. The composite spectrum covers the wavelength range 700-6600 A in the rest frame and has a mean signal-to-noise ratio of 150 per 1 A pixel and reaches a maximum of {approx}300 in the range 2500-3500 A. Equivalent widths are measured from metal absorption lines from the Ly{alpha} line to {approx}5200 A, and associated metal and hydrogen lines are identified between the Lyman break and Ly{alpha} line. The average transmission within the Lyman forest is consistent with that found along quasar lines of sight. We find a temporal variation in fine-structure lines when dividing the sample into bursts observed within 2 hr from their trigger and those observed later. Other lines in the predominantly neutral gas show variations too, but this is most likely a random effect caused by weighting of individual strong absorption lines and which mimics a temporal variation. Bursts characterized with high- or low-prompt GRB energy release produce afterglows with similar absorption line strengths, and likewise for bursts with bright or faint optical afterglows. Bursts defined as dark from their optical to X-ray spectral index have stronger absorption lines relative to the optically bright bursts. The composite spectrum has strong Ca II and Mg II absorption lines as commonly found in dusty galaxies, however, we find no evidence for dust or a significant molecular content based on the non-detection of diffuse interstellar bands. Compared to starburst galaxy spectra, the GRB composite has much stronger fine-structure lines, while metal absorption lines are weaker.

  8. [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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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).

  15. 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.

  16. 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.

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

    NASA Astrophysics Data System (ADS)

    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 σv=a+bv2. We determine that this significantly increases the gamma-ray power if b/a≳106. 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.

  19. 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.

  20. 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.

  1. Hard x-ray telescope concentrator for astrophysical mission Spectrum-X-Gamma

    NASA Astrophysics Data System (ADS)

    Pavlinsky, M.; Arefiev, V.; Churazov, E.; Gilfanov, M.; Grigorovich, S.; Litvin, D.; Lapshov, I.; Levin, V.; Akimov, V.; Semena, N.; Tkachenko, A.; Vikhlinin, A.; Sunyaev, R.; Ramsey, B. D.; Gubarev, M. V.; Elsner, R. F.; O'Dell, S. L.; Weisskopf, M. C.

    2007-09-01

    The hard X-ray telescope-concentrator ART-XC on board the Spectrum-X-Gamma X-ray astrophysical observatory (launching in 2011) is one of the main instruments of the mission. The instrument will be used for an all-sky survey and then for pointed observations which are planned for the first four and the next three years of the Mission, respectively. ART-XC will be sensitive in the 4-30 keV energy range and will have an effective area of several hundred square centimeters at 10 keV. It will have a field of view of about ~28 arcmin, angular resolution better than 1 arcmin and will be an order of magnitude more sensitive than the current generation of collimated instruments and coded mask telescopes in the survey mode and a two or three orders of magnitude more sensitive in the pointing mode. With its high sensitivity in the hard X-ray band and good imaging capabilities, ART-XC will extend the operating energy range of the observatory (complementing the capabilities of the primary science instrument eROSITA), thus significantly enhancing the mission both in the all-sky survey over the energy band 4-10 keV and, especially, in pointed observations over the energy band 4-30 keV. During the 4-year survey, this ART-XC would detect more than ~10 4 sources over 4-10 keV. For a 10 5 second pointed observation, the telescope will provide better than 10 microCrab sensitivity in the 4-20 keV energy range.

  2. Singular Spectrum Analysis in Astrometry and Geodynamics

    NASA Astrophysics Data System (ADS)

    Vityazev, V. V.; Miller, N. O.; Prudnikova, E. Ja.

    2010-10-01

    The paper presents the possibilities of the Singular Spectrum Analyses on the examples of its application to several astrometric and geodynamic time series. The comparisons of results obtained by other often used methods (Fourier transform, Wavelet Transform, different filter methods) are given. The Singular Spectrum Analyses method was used for the investigation of the Chandler wobble (CW), which was extracted from the IERS Pole coordinates and latitude variations at Pulkovo. The CW amplitude and phase variations were examined by means of the Hilbert transform. The main conclusion which can be made from this study is: we have found two epochs of deep CW amplitude decreases near 1850 and 2005, which are also accompanied by a large phase jump, similar to well known event in 1920s. The investigation of first latitude observations at Pulkovo (1840-1855) was executed with the aim to gain and analyse the sum of Chandler and annual components from very small quantity of very noisy observations. The SSA is applied for investigation of the zenith troposphere delay time-series derived from observations of several VLBI stations. Combined IVS time-series of the zenith wet and total troposphere delays obtained in IGG were used for analysis. For all stations under consideration the non-linear trends and the seasonal components with annual and semiannual periods were found. Some interesting peculiarities were found to be individual for every stations. Comparison of the trends with meteorological parameters is also presented.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

    2006-03-09

    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.

  8. Study of the very high energy gamma-ray spectrum from the Galactic Center and future prospects

    NASA Astrophysics Data System (ADS)

    Belikov, Alexander V.; Moulin, Emmanuel; Silk, Joseph

    2016-11-01

    Ground-based gamma-ray observations of the Galactic Center region have revealed a high energy gamma-ray source spatially coincident with the gravitational centroid of our Galaxy. The pointlike emission detected by HESS exhibits an energy cutoff at about 10 TeV. We identify the parameters of the best fit of the exponential and the superexponential cutoff models to the spectrum of the pointlike source and find that the superexponential one provides a similar quality of fit to the spectrum of the pointlike source as the best-fit exponential cutoff model, while a dark matter interpretation does not provide as good a fit in the whole energy range of the signal. Based on the magnitude of the flux we derive constraints in the plane of the slope of the density profile γ and the critical radius, below which the density is assumed to be constant, rc. Motivated by recent results on the spectrum and morphology from HESS and by the possible observation of a superexponential cutoff, we forecast the observations of superexponential versus exponential cutoffs by the upcoming Cherenkov Telescope Array. We derive a formula for J -factor in the small-angle approximation and propose approximate morphological constraints on the central source.

  9. On the high energy cut-off in the gamma-ray spectrum from Cygnus X-3

    NASA Astrophysics Data System (ADS)

    Stephens, S. A.; Verma, R. P.

    The effect of magnetic pair production on the high energy gamma-rays from Cygnus X-3 is examined, while traversing the field associated with the radio emitting region of this source. It is shown that such a process would result in a sharp steepening of the gamma-ray spectrum beyond about 10 to the 15th eV. Using the observed spectral steepening, a field strength of 0.7 gauss in the region about 10 to the 14th cms is derived, where most of the observed radio emission takes place. The observed light curve shows only one significant peak at a phase of about 0.2 from the X-ray minimum. This could result from the magnetic bending of the charged particles from the pulsar before interacting with the enshrouded matter. It is predicted that the relative contribution of steady flux would increase beyond 10 to the 16th eV.

  10. Prompt Gamma Ray Analysis of Soil Samples

    SciTech Connect

    Naqvi, A.A.; Khiari, F.Z.; Haseeb, S.M.A.; Hussein, Tanvir; Khateeb-ur-Rehman; Isab, A.H.

    2015-07-01

    Neutron moderation effects were measured in bulk soil samples through prompt gamma ray measurements from water and benzene contaminated soil samples using 14 MeV neutron inelastic scattering. The prompt gamma rays were measured using a cylindrical 76 mm x 76 mm (diameter x height) LaBr{sub 3}:Ce detector. Since neutron moderation effects strongly depend upon hydrogen concentration of the sample, for comparison purposes, moderation effects were studied from samples containing different hydrogen concentrations. The soil samples with different hydrogen concentration were prepared by mixing soil with water as well as benzene in different weight proportions. Then, the effects of increasing water and benzene concentrations on the yields of hydrogen, carbon and silicon prompt gamma rays were measured. Moderation effects are more pronounced in soil samples mixed with water as compared to those from soil samples mixed with benzene. This is due to the fact that benzene contaminated soil samples have about 30% less hydrogen concentration by weight than the water contaminated soil samples. Results of the study will be presented. (authors)

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Passive Gamma Analysis of the Boiling-Water-Reactor Assemblies

    SciTech Connect

    Vo, Duc Ta; Favalli, Andrea

    2016-03-31

    Passive gamma analysis can be used to determine BU and CT of BWR assembly. The analysis is somewhat more complicated and less effective than similar method for PWR assemblies. From the measurements along the lengths of the BWR1 and BWR9 assemblies, there are hints that we may be able to use their information to help improve the model functions for better results.

  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. Anomaly Detection in Gamma-Ray Vehicle Spectra with Principal Components Analysis and Mahalanobis Distances

    SciTech Connect

    Tardiff, Mark F.; Runkle, Robert C.; Anderson, K. K.; Smith, L. E.

    2006-01-23

    The goal of primary radiation monitoring in support of routine screening and emergency response is to detect characteristics in vehicle radiation signatures that indicate the presence of potential threats. Two conceptual approaches to analyzing gamma-ray spectra for threat detection are isotope identification and anomaly detection. While isotope identification is the time-honored method, an emerging technique is anomaly detection that uses benign vehicle gamma ray signatures to define an expectation of the radiation signature for vehicles that do not pose a threat. Newly acquired spectra are then compared to this expectation using statistical criteria that reflect acceptable false alarm rates and probabilities of detection. The gamma-ray spectra analyzed here were collected at a U.S. land Port of Entry (POE) using a NaI-based radiation portal monitor (RPM). The raw data were analyzed to develop a benign vehicle expectation by decimating the original pulse-height channels to 35 energy bins, extracting composite variables via principal components analysis (PCA), and estimating statistically weighted distances from the mean vehicle spectrum with the mahalanobis distance (MD) metric. This paper reviews the methods used to establish the anomaly identification criteria and presents a systematic analysis of the response of the combined PCA and MD algorithm to modeled mono-energetic gamma-ray sources.

  1. Energy spectrum and mass composition of primary cosmic radiation in the region above the knee from the GAMMA experiment

    NASA Astrophysics Data System (ADS)

    Martirosov, Romen

    The energy spectrum of the primary cosmic radiation in the energy range 1 - 100 PeV and the extensive air shower (EAS) characteristics obtained on the basis of the expanded data bank of the GAMMA experiment (Mt. Aragats, Armenia) are presented. With increased statistics we confirm our previous results on the energy spectrum. The spectral index above the knee is about -3.1, but at energies beyond 20 PeV a flattening of the spectrum is observed. The existence of the 'bump' at about 70 PeV is confirmed with a significance of more than 4{\\sigma}. In the energy range of 10 - 100 PeV the shower age becomes energy independent and we observe a direct proportionality of the EAS size to the primary energy. This suggests an approximately constant depth of the EAS maximum in this energy range. This is evidence in favour of an increasing average mass of primary particles at energies above 20 PeV. The additional source scenario, which is a possible explanation of the 'bump' in the spectrum, also leads to the conclusion of increasing mass of the primary cosmic rays. A comparison with the data of other experiments is presented.

  2. 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.

  3. Energy spectrum of medium energy gamma-rays from the galactic center region. [experimental design

    NASA Technical Reports Server (NTRS)

    Palmeira, R. A. R.; Ramanujarao, K.; Dutra, S. L. G.; Bertsch, D. L.; Kniffen, D. A.; Morris, D. J.

    1978-01-01

    A balloon-borne magnetic core digitized spark chamber with two assemblies of spark-chambers above and below the scintillation counters was used to measure the medium energy gamma ray flux from the galactic center region. Gamma ray calculations are based on the multiple scattering of the pair electrons in 15 aluminum plates interleaved in the spark chamber modules. Counting rates determined during ascent and at ceiling indicate the presence of diffuse component in this energy range. Preliminary results give an integral flux between 15 and 70 MeV compared to the differential points in other results.

  4. 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.

  5. 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.

  6. 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.

  7. Spectrum analysis for introductory musical acoustics

    NASA Astrophysics Data System (ADS)

    Smedley, John E.

    1998-02-01

    A "real time" fast Fourier transform spectrum analyzer facilitates several experiments for an introductory course in musical acoustics. With its rapidly updated display, the time-dependent vibrations of an aluminum bar are easily studied. Using longer time acquisitions and correspondingly higher resolution facilitates the study of string inharmonicities, resonant energy transfer, and sound radiation patterns in guitar acoustics.

  8. [Backscattering spectrum analysis of nonspheroid soot particle].

    PubMed

    Xing, Jian; Sun, Xiao-gang; Yuan, Gui-bin; Qi, Xu; Tang, Hong

    2010-08-01

    In the process of measuring soot concentration and grain diameter, the backscattering spectrum of soot particle model was calculated to ascertain and analyze main effective factor of backscattering intensity. In the present paper, ellipsoid, column and generalized Chebyshev, three nonspheroid models, were selected according to micrograph of practical soot particle, which aims to simulate practical soot particle with equivalent diameter of about 1 microm. T-matrix method was used to calculate backscattering spectrum of the three nonspheriod models, and the main effective factor curves of intensity were obtained, too. Both numerical computer simulations and experimental results illustrate that nonspheroid particle backscattering intensity is stronger than that of spheroid particle in the visible/infrared spectrum band, especially for generalized Chebyshev model, whose backscattering intensity can be even 3.5 times higher than that of forward scattering. Meanwhile, the absorbency non-spheroid particle (complex refractive index m = 1.57 - 0.56i) backscattering intensity is stronger than that of non-absorbency nonspheriod particle (complex refractive index m = 1.57 - 0.001i). Furthermore, with the increase in particle equivalent radius, the light source wavelength also needs to be increase to obtain more light intensity information. The backscattering light spectrum information provides a reasonable basis for selecting light source and measure angle.

  9. [Measurement and analysis of absorption spectrum of human blood].

    PubMed

    Zhao, Zhi-Min; Xin, Yu-Jun; Wang, Le-Xin; Zhu, Wei-Hua; Zheng, Min; Guo, Xin

    2008-01-01

    The present paper puts forward a method of disease diagnosis by using the technology of spectrum analysis of human blood serum. The generation mechanism of absorption spectrum is explained and the absorption spectra of the normal blood serum and the sick blood serum are listed from the experiments of absorption spectrometry. Though the value of absorbency of the sick blood serum is almost equal to that of the normal blood serum in the most absorption spectra, there are some differences around 278 nm in the absorption spectrum. The absorbency of the blood serum with hyperglycemia is greater than that of the normal blood serum at 285 nm in the spectrum, and besides, there comes a peak shift of absorption with hyperglycemia. In the absorption spectrum of the blood serum with hypercholesterolemia, there is a clear absorption peak at 414 nm. However there is not any peak at that wavelength in the absorption spectrum of the normal blood serum. Through comparing the characters of the spectrum, we can judge if the blood sample is or not, and this blood analysis is a new method for the diagnosis of disease. Compared with other methods of blood measurements, the method of absorption spectrum analysis of blood serum presented in this paper, is more convenient for measurement, simpler for analysis, and easier to popularize.

  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.

    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.

  11. An upper limit on interstellar C IV in the spectrum of gamma-2 Velorum

    NASA Technical Reports Server (NTRS)

    Lengyel-Frey, D.; Stecher, T. P.; West, D. K.

    1975-01-01

    An upper limit on the column density of C IV along the line of sight to gamma-2 Vel is derived from upper limits placed on the equivalent widths of the interstellar C IV doublet with rest wavelengths at 1548.20 A and 1550.77 A. A lower limit of 250,000 K is calculated for the electron temperature of O VI emitting regions by combining the C IV results with a measurement of the column density of interstellar O VI for the same star and using calculations for the relative ionization of some abundant elements as a function of electron temperature in a low-density plasma. Since gamma-2 Vel is in the central part of the Gum Nebula, the high temperature suggested by these results is shown to support the idea that a high-temperature phase of the interstellar medium, possibly maintained by supernova explosions, may exist.-

  12. 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.

  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. Analysis of Data from the Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory

    NASA Technical Reports Server (NTRS)

    Kniffen, Donald A.; Elliott, William W.

    1999-01-01

    The final report consists of summaries of work proposed, work accomplished, papers and presentations published and continuing work regarding the cooperative agreement. The work under the agreement is based on high energy gamma ray source data analysis collected from the Energetic Gamma-Ray Experiment Telescope (EGRET).

  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 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. [Infrared absorption spectrum analysis and its application to blood].

    PubMed

    Wang, Le-xin; Zhao, Zhi-min; Yao, Hong-bing; Chen, Yu-ming; Shi, Lei; Gao, Yong

    2002-12-01

    The technology of infrared absorption spectrum is a branch of optical ment measurement technology, and the research on the application of infrared spectrum plays an important role in the development of technology of optical measurement. In this paper, the analysis technology of blood infrared absorption spectrum is presented. By comparison, the difference of the spectra between normal and abnormal blood samples was obtained. The infrared absorption spectra of normal blood sample and abnormal blood sample were detected, and the differences between the spectra are presented. And the analysis results of the infrared absorption spectra of normal whole blood, serum and hyperglycemia are presented also. All of these provide an experimental basis for the diagnosis of diseases, which is valuable for application. This technology features easy operation, convenient analysis and suitability for advanced experiment. The work offers a new way in the research on the application of infrared absorption spectrum.

  2. 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.

  3. 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.

  4. 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

    ... Collection; 60-day Comment Request: Autism Spectrum Disorder Research Portfolio Analysis SUMMARY: In... this publication. Proposed Collection: Autism Spectrum Disorder (ASD) Research Portfolio Analysis,...

  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. 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.

  7. 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

  8. 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. 

  9. Reference MWA EoR Power Spectrum analysis

    NASA Astrophysics Data System (ADS)

    Hazelton, Bryna; Pober, Jonathan; Beardsley, Adam; Morales, Miguel F.; Sullivan, Ian S.; MWA Collaboration

    2015-01-01

    Observations of the Epoch of Reionization using redshifted 21cm HI emission promise to provide sensitive new cosmological constraints in the next few years. The current generation of HI EoR telescopes are targeting a statistical detection of the EoR in the power spectrum of the 21cm emission. The principal challenge lies in extracting the faint cosmological signal in the face of bright foregrounds and instrumental systematics that threaten to overwhelm it.We present the UW EoR power spectrum code, the reference code for the MWA and the first power spectrum analysis to analytically propagate the error bars through the full data analysis pipeline. We demonstrate the sensitivity of the power spectrum as a diagnostic tool for identifying subtle systematics and show power spectra of the first season of MWA observations.

  10. Energy spectrum analysis - A model of echolocation processing. [in animals

    NASA Technical Reports Server (NTRS)

    Johnson, R. A.; Titlebaum, E. L.

    1976-01-01

    The paper proposes a frequency domain approach based on energy spectrum analysis of the combination of a signal and its echoes as the processing mechanism for the echolocation process used by bats and other animals. The mechanism is a generalized wide-band one and can account for the large diversity of wide-band signals used for orientation. The coherency in the spectrum of the signal-echo combination is shown to be equivalent to correlation.

  11. FFT-Based Spectrum Analysis Using a Digital Signal Processor

    DTIC Science & Technology

    2007-11-02

    thus far incomplete) Search for ExtraTerrestrial Intelligence (SETI) all rely on detecting the presence of radio signals of unknown frequency, power...instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send...Spectrum analysis is the context of this thesis. Spectrum conflict management, sig- nals intelligence , technical security, space probe telemetry, and the

  12. 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.

  13. 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.

  14. The X-Ray Time Variability and Spectrum of Gamma-Cassiopeiae X:0053+604

    NASA Astrophysics Data System (ADS)

    Parmar, A. N.; Israel, G. L.; Stella, L.; White, N. E.

    1993-08-01

    A 30 h duration EXOSAT observation made in 1985 December is used to examine the X-ray time variability and spectrum of the Be star γ Cassiopeiae (X 0053+604). We find that the X-ray lightcurve is dominated by irregular energy-independent flaring on time-scales ≳ 100 s. This flaring markedly decreases the sensitivity to any periodic signals. We find no evidence for the 6000 5 oscillations reported by Frontera et al. (1987) from an earlier EXOSAT observation. We suggest that these arise from statistical fluctuations in the red noise power. The X-ray spectrum of γ Cas can either be modeled by thermal emission from an optically thin plasma with a temperature of 12 keV, or by a cut-off power-law model with a narrow iron line at an energy of 6.67 keV. The origin of the X-ray emission in this system remains open since its spectral and temporal properties are consistent with both an acereting neutron star and a white dwarf while its high temperature argues against a coronal mechanism.

  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. Acoustic spectrum analysis for gyro bearings

    NASA Astrophysics Data System (ADS)

    Heitzman, C. E.

    1981-08-01

    An acoustic system analyzer has been developed that will be an aid in bearing analysis for displacement gyros. The phenomenon of the Fourier Transform has made possible the development of an optical processor that operates by the interaction of light from a light emitting diode array sweeping across a binary frequency mask and through lenses onto a vidicon tube. This arrangement performs the Fourier Transform of large time samples of sound in a parallel process, preserving amplitude, frequency and phase information. The resultant information can then be entered into a computer for programmed analysis or displayed for visual analysis of the condition of gyro-bearings.

  18. Surface roughness monitoring by singular spectrum analysis of vibration signals

    NASA Astrophysics Data System (ADS)

    García Plaza, E.; Núñez López, P. J.

    2017-02-01

    This study assessed two methods for enhanced surface roughness (Ra) monitoring based on the application of singular spectrum analysis (SSA) to vibrations signals generated in workpiece-cutting tool interaction in CNC finish turning operations i.e., the individual analysis of principal components (I-SSA), and the grouping analysis of correlated principal components (G-SSA). Singular spectrum analysis is a non-parametric technique of time series analysis that decomposes a signal into a set of independent additive time series referred to as principal components. A number of experiments with different cutting conditions were performed to assess surface roughness monitoring using both of these methods. The results show that singular spectrum analysis of vibration signal processing discriminated the frequency ranges effective for predicting surface roughness. Grouping analysis of correlated principal components (G-SSA) proved to be the most efficient method for monitoring surface roughness, with optimum prediction and reliability results at a lower analytical-computational cost. Finally, the results show that singular spectrum analysis is an ideal method for analyzing vibration signals applied to the on-line monitoring of surface roughness.

  19. Singular spectrum analysis for time series with missing data

    USGS Publications Warehouse

    Schoellhamer, D.H.

    2001-01-01

    Geophysical time series often contain missing data, which prevents analysis with many signal processing and multivariate tools. A modification of singular spectrum analysis for time series with missing data is developed and successfully tested with synthetic and actual incomplete time series of suspended-sediment concentration from San Francisco Bay. This method also can be used to low pass filter incomplete time series.

  20. Bayesian Block Analysis of Terrestrial Gamma-ray Flashes Detected by the Gamma-ray Burst Monitor

    NASA Astrophysics Data System (ADS)

    Roberts, O.; Fitzpatrick, G.; McBreen, S.; Briggs, M. S.

    2014-12-01

    The Gamma-ray Burst Monitor (GBM) is one of two instruments aboard the Fermi Gamma-ray Space Telescope. Since the launch of the spacecraft in 2008, a sequence of flight software enhancements and new observing modes have resulted in the detection of over 2500 Terrestrial Gamma-ray Flashes (TGFs) by GBM. As a result, a catalogue of TGFs will be published and released online to provide the community with information on the most important characteristics of these TGFs. We will present a Bayesian Block analysis of the TGFs of this catalogue, obtaining for this large sample size the durations, peak times, hardness ratios, and delays between soft and hard counts.

  1. 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.

  2. The effects of temperature on ESR spectrum of gamma-irradiated ammonium tartrate

    NASA Astrophysics Data System (ADS)

    Polat, Mustafa; Korkmaz, Mustafa

    2009-11-01

    Unirradiated ammonium tartrate (AT) samples do not exhibit any ESR signal. However, irradiation produces an unresolved singlet at g=2.0034±0.0006 with two shoulders at g1=2.0093±0.0006 and g2=2.0048±0.0006. The dose-response curve was found to increase linearly with the applied radiation doses in the range of 0.1-2.0 kGy and the slope of this curve was increased as the modulation amplitude increased. The activation energy value Ea=69.0±1.2 kJ/mol was calculated from Arrhenius plot for the radical species responsible from ESR spectrum of irradiated AT.

  3. 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.

  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. [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

  6. The energy spectrum of anomalous X-ray pulsars and soft gamma-ray repeaters

    NASA Astrophysics Data System (ADS)

    Trümper, J. E.; Zezas, A.; Ertan, Ü.; Kylafis, N. D.

    2010-07-01

    Context. Anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) exhibit characteristic X-ray luminosities (both soft and hard) of around 1035 erg s-1 and characteristic power-law, hard X-ray spectra extending to about 200 keV. Two AXPs also exhibit pulsed radio emission. Aims: Assuming that AXPs and SGRs accrete matter from a fallback disk, we attempt to explain both the soft and the hard X-ray emission as the result of the accretion process. We also attempt to explain their radio emission or the lack of it. Methods: We test the hypothesis that the power-law, hard X-ray spectra are produced in the accretion flow mainly by bulk-motion Comptonization of soft photons emitted at the neutron star surface. Fallback disk models invoke surface dipole magnetic fields of 1012 - 1013 G, which is what we assume here. Results: Unlike normal X-ray pulsars, for which the accretion rate is highly super-Eddington, the accretion rate is approximately Eddington in AXPs and SGRs and thus the bulk-motion Comptonization operates efficiently. As an illustrative example we reproduce both the hard and the soft X-ray spectra of AXP 4U 0142+61 well using the XSPEC package compTB. Conclusions: Our model seems to explain both the hard and the soft X-ray spectra of AXPs and SGRs, as well as their radio emission or the lack of it, in a natural way. It might also explain the short bursts observed in these sources. On the other hand, it cannot explain the giant X-ray outbursts observed in SGRs, which may result from the conversion of magnetic energy in local multipole fields.

  7. Angular power spectrum of the diffuse gamma-ray emission as measured by the Fermi Large Area Telescope and constraints on its dark matter interpretation

    NASA Astrophysics Data System (ADS)

    Fornasa, Mattia; Cuoco, Alessandro; Zavala, Jesús; Gaskins, Jennifer M.; Sánchez-Conde, Miguel A.; Gomez-Vargas, German; Komatsu, Eiichiro; Linden, Tim; Prada, Francisco; Zandanel, Fabio; Morselli, Aldo

    2016-12-01

    The isotropic gamma-ray background arises from the contribution of unresolved sources, including members of confirmed source classes and proposed gamma-ray emitters such as the radiation induced by dark matter annihilation and decay. Clues about the properties of the contributing sources are imprinted in the anisotropy characteristics of the gamma-ray background. We use 81 months of Pass 7 Reprocessed data from the Fermi Large Area Telescope to perform a measurement of the anisotropy angular power spectrum of the gamma-ray background. We analyze energies between 0.5 and 500 GeV, extending the range considered in the previous measurement based on 22 months of data. We also compute, for the first time, the cross-correlation angular power spectrum between different energy bins. We find that the derived angular spectra are compatible with being Poissonian, i.e. constant in multipole. Moreover, the energy dependence of the anisotropy suggests that the signal is due to two populations of sources, contributing, respectively, below and above ˜2 GeV . Finally, using data from state-of-the-art numerical simulations to model the dark matter distribution, we constrain the contribution from dark matter annihilation and decay in Galactic and extra-Galactic structures to the measured anisotropy. These constraints are competitive with those that can be derived from the average intensity of the isotropic gamma-ray background.

  8. {eta} Prime {yields}{pi}{sup 0}{gamma}{gamma} and {eta} Prime {yields}{eta}{gamma}{gamma}: A primer analysis

    SciTech Connect

    Escribano, Rafel

    2012-10-23

    The electromagnetic rare decays {eta} Prime {yields}{pi}{sup 0}{gamma}{gamma} and {eta} Prime {yields}{pi}{sup 0}{gamma}{gamma} are analysed for the first time and their predicted branching ratios given. The vector meson exchange dominant contribution is treated using Vector Meson Dominance and the scalar component is estimated by means of the Linear Sigma Model. The agreement between our calculation and the measurement of the related process {eta} Prime {yields}{pi}{sup 0}{gamma}{gamma} is a check of the procedure. Scalar meson effects are seen to be irrelevant for {eta} Prime {yields}{pi}{sup 0}{gamma}{gamma}, while a significant scalar contribution due to the {sigma}(500) resonance seems to emerge in the case of {eta} Prime {yields}{pi}{sup 0}{gamma}{gamma}. Future measurements coming from KLOE-2, Crystal Ball, WASA, and BES-III will elucidate if any of these processes carry an important scalar contribution or they are simply driven by the exchange of vector mesons.

  9. Optimisation of beryllium-7 gamma analysis following BCR sequential extraction.

    PubMed

    Taylor, A; Blake, W H; Keith-Roach, M J

    2012-03-30

    The application of cosmogenic (7)Be as a sediment tracer at the catchment-scale requires an understanding of its geochemical associations in soil to underpin the assumption of irreversible adsorption. Sequential extractions offer a readily accessible means of determining the associations of (7)Be with operationally defined soil phases. However, the subdivision of the low activity concentrations of fallout (7)Be in soils into geochemical fractions can introduce high gamma counting uncertainties. Extending analysis time significantly is not always an option for batches of samples, owing to the on-going decay of (7)Be (t(1/2)=53.3 days). Here, three different methods of preparing and quantifying (7)Be extracted using the optimised BCR three-step scheme have been evaluated and compared with a focus on reducing analytical uncertainties. The optimal method involved carrying out the BCR extraction in triplicate, sub-sampling each set of triplicates for stable Be analysis before combining each set and coprecipitating the (7)Be with metal oxyhydroxides to produce a thin source for gamma analysis. This method was applied to BCR extractions of natural (7)Be in four agricultural soils. The approach gave good counting statistics from a 24 h analysis period (~10% (2σ) where extract activity >40% of total activity) and generated statistically useful sequential extraction profiles. Total recoveries of (7)Be fell between 84 and 112%. The stable Be data demonstrated that the extraction procedure had a high reproducibility (<1% RSD), thus gamma counting uncertainties dominated the overall uncertainty. In addition, extractions of soil equilibrated with stable Be at a concentration below the Cation Exchange Capacity (CEC) of the soil demonstrated that doubling the soil:solution ratio to enhance the mass of soil used in a sequential extraction scheme affects the apparent distribution of approximately 10% of the total Be. At high concentration, stable Be was found to be a poor proxy for

  10. 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).

  11. 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).

  12. 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.

  13. Power spectrum analysis of astronomical photographs digitised with small apertures.

    NASA Astrophysics Data System (ADS)

    Stobie, R. S.; Okamura, S.; Davenhall, A. C.; MacGillivray, H. T.

    A total of 8 UK Schmidt Telescope plates, 2 Anglo-Australian Telescope prime focus plates and 2 Palomar Observatory Sky Survey (POSS) copies were measured with a scanning aperture of 11 μm and a pixel spacing of 16 μm. Power spectrum analysis of the resulting data shows the plate noise (with the exception of the POSS plates) to correspond to almost white noise over the frequency range 0.1 - 60 cycles mm-1. The signal-to-noise power spectrum is shown to be a useful tool for measuring the information content of an astronomical photograph. A comparison was made of the information content of a survey quality UKST IIIaJ plate and atlas quality copies on very fine-grained emulsion. Power spectrum analysis of exactly the same area on the original plate and copies showed no significant degradation in either emulsion noise or image content of the copy relative to the original.

  14. Evidence for Enhanced 3He in Flare-accelerated Particles Based on New Calculations of the Gamma-Ray Line Spectrum

    NASA Astrophysics Data System (ADS)

    Murphy, R. J.; Kozlovsky, B.; Share, G. H.

    2016-12-01

    The 3He abundance in impulsive solar energetic particle (SEP) events is enhanced up to several orders of magnitude compared to its photospheric value of [3He]/[4He] = 1-3 × 10-4. Interplanetary magnetic field and timing observations suggest that these events are related to solar flares. Observations of 3He in flare-accelerated ions would clarify the relationship between these two phenomena. Energetic 3He interactions in the solar atmosphere produce gamma-ray nuclear-deexcitation lines, both lines that are also produced by protons and α particles and lines that are essentially unique to 3He. Gamma-ray spectroscopy can, therefore, reveal enhanced levels of accelerated 3He. In this paper, we identify all significant deexcitation lines produced by 3He interactions in the solar atmosphere. We evaluate their production cross sections and incorporate them into our nuclear deexcitation-line code. We find that enhanced 3He can affect the entire gamma-ray spectrum. We identify gamma-ray line features for which the yield ratios depend dramatically on the 3He abundance. We determine the accelerated 3He/α ratio by comparing these ratios with flux ratios measured previously from the gamma-ray spectrum obtained by summing the 19 strongest flares observed with the Solar Maximum Mission Gamma-Ray Spectrometer. All six flux ratios investigated show enhanced 3He, confirming earlier suggestions. The 3He/α weighted mean of these new measurements ranges from 0.05 to 0.3 (depending on the assumed accelerated α/proton ratio) and has a <1 × 10-3 probability of being consistent with the photospheric value. With the improved code, we can now exploit the full potential of gamma-ray spectroscopy to establish the relationship between flare-accelerated ions and 3He-rich SEPs.

  15. Discerning the Gamma-Ray-emitting Region in the Flat Spectrum Radio Quasars

    NASA Astrophysics Data System (ADS)

    Zheng, Y. G.; Yang, C. Y.; Zhang, L.; Wang, J. C.

    2017-01-01

    A model-dependent method is proposed to determine the location of the γ-ray-emitting region for a given flat spectrum radio quasar (FSRQ). In the model, the extra-relativistic electrons are injected at the base of the jet and non-thermal photons are produced by both synchrotron radiation and inverse-Compton (IC) scattering in the energy dissipation region. The target photons dominating IC scattering originate from both synchrotron photons and external ambient photon fields, and the energy density of external radiation field is a function of the distance between the position of the dissipation region and a central supermassive black hole, and their spectra are seen in the comoving frame. Moreover, the energy dissipation region could be determined by the model parameter through reproducing the γ-ray spectra. Such a model is applied to reproduce the quasi-simultaneous multi-wavelength observed data for 36 FSRQs. In order to define the width of the broad-line region (BLR) shell and dusty molecular torus (MT) shell, a simple numerical constraint is used to determine the outer boundary of the BLR and dusty MT. Our results show that (1) the γ-ray-emitting regions are located at the range from 0.1 to 10 pc; (2) the γ-ray-emitting regions are located outside the BLRs and within the dusty molecular tori; and (3) the γ-ray-emitting regions are located closer to the dusty MT ranges than the BLRs. Therefore, it may be concluded that direct evidence for the far site scenario could be obtained on the basis of the model results.

  16. Observation of parity nonconservation in the integrated. gamma. spectrum from (n,. gamma. ) reactions in Cl, Br, Cd, Sn, and La nuclei

    SciTech Connect

    Vesna, V.A.; Kolomenskii, E.A.; Lobashev, V.M.; Nazarenko, V.A.; Pirozhkov, A.N.; Smotritskii, L.M.; Sobolev, Y.V.; Titov, N.A.

    1982-09-05

    A P-odd asymmetry has been observed in the emission of ..gamma.. rays upon the capture of polarized thermal neutrons by Cl, Br, and La nuclei. A circular polarization of the ..gamma.. rays has been observed during the capture of unpolarized neutrons by Cl, Br, Sn, and La nuclei.

  17. 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.

  18. 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.

  19. 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…

  20. 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

  1. 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.

  2. Hardening anisotropy of {gamma}/{gamma}{prime} superalloy single crystals. 2: Numerical analysis of heterogeneity effects

    SciTech Connect

    Estevez, R.; Hoinard, G.; Franciosi, P.

    1997-04-01

    In the first part of this study, the {gamma}/{gamma}{prime} superalloy single crystals yield stress and hardening anisotropy were experimentally estimated at 650 C, assuming homogeneous plasticity, G. Hoinard, R. Estevez and P. Franciosi, Acta Metall. 43, 1593 (1995). Here alloy morphology is regarded in two different ways: first as a two-phase anisotropic material with a uniform {gamma} matrix, describing the {gamma}{prime} precipitates arrangement with the help of an elementary pattern of inclusions; then treating the {gamma} matrix as a three (geometrical) phase medium, i.e., the three families of orthogonal {gamma} layers separating the precipitates, to estimate the matrix behavior heterogeneity in a 4-phase modelling of the alloy. Both {gamma} and {gamma}{prime} phases are treated as elastic-plastic crystalline media deforming by octahedral and cubic slip, and the models are based on the self consistent approximation. The alloy elasticity limit, internal stresses and hardening anisotropy are discussed with regard to the chosen behavior description for each phase, and behavior simulations are compared to experimental information.

  3. [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.

  4. 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.

  5. 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.

  6. The Spectrum of Isotropic Diffuse Gamma-Ray Emission between 100 MeV and 820 GeV

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; Ajello, M.; Albert, A.; Atwood, W. B.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caragiulo, M.; Caraveo, P. A.; Cavazzuti, E.; Cecchi, C.; Charles, E.; Chekhtman, A.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Cuoco, A.; Cutini, S.; D'Ammando, F.; de Angelis, A.; de Palma, F.; Dermer, C. D.; Digel, S. W.; Silva, E. do Couto e.; Drell, P. S.; Favuzzi, C.; Ferrara, E. C.; Focke, W. B.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Germani, S.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Godfrey, G.; Gomez-Vargas, G. A.; Grenier, I. A.; Guiriec, S.; Gustafsson, M.; Hadasch, D.; Hayashi, K.; Hays, E.; Hewitt, J. W.; Ippoliti, P.; Jogler, T.; Jóhannesson, G.; Johnson, A. S.; Johnson, W. N.; Kamae, T.; Kataoka, J.; Knödlseder, J.; Kuss, M.; Larsson, S.; Latronico, L.; Li, J.; Li, L.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Manfreda, A.; Massaro, F.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nemmen, R.; Nuss, E.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Paneque, D.; Panetta, J. H.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Reposeur, T.; Ritz, S.; Romani, R. W.; Sánchez-Conde, M.; Schaal, M.; Schulz, A.; Sgrò, C.; Siskind, E. J.; Spandre, G.; Spinelli, P.; Strong, A. W.; Suson, D. J.; Takahashi, H.; Thayer, J. G.; Thayer, J. B.; Tibaldo, L.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja, E.; Uchiyama, Y.; Vianello, G.; Werner, M.; Winer, B. L.; Wood, K. S.; Wood, M.; Zaharijas, G.; Zimmer, S.

    2015-01-01

    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) × 10-6 cm-2 s-1 sr-1 above 100 MeV, with an additional +15%/-30% systematic uncertainty due to the Galactic diffuse foregrounds.

  7. Power spectrum analysis of astronomical photographs digitised with small apertures

    NASA Astrophysics Data System (ADS)

    Stobie, R. S.; Okamura, S.; Davenhall, A. C.; MacGillivray, H. T.

    1984-04-01

    Noise characteristics of images on 8 UK Schmidt Telescope plates, 2 Anglo-Australian Telescope prime focus plates, and 2 Palomar Observatory Sky Survey (POSS) copies (comprising 3 different emulsion types) were measured with a scanning aperture of 11 microns and a pixel spacing of 16 microns. Power spectrum analysis shows plate noise (except POSS plates) to correspond to almost white noise over the frequency range 0.1 to 60 cycles/mm. The signal-to-noise power spectrum is shown to be a useful tool for measuring the information content of an astronomical photograph. Macronoise computed over 8 x 8 mm regions on the plates varies as the minus half power of the aperture area. Information content of a survey quality IIIa-J plate and atlas quality copies on very fine-grained emulsion were compared. Analysis shows no significant degradation in emulsion noise or image content of the copy relative to the original.

  8. 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.

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

    SciTech Connect

    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.

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

    DOE PAGES

    Vo, D.; Favalli, A.; Grogan, B.; ...

    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 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

  11. 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.

  12. [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.

  13. Isotopic ratio of 129I/127I in seaweed measured by neutron activation analysis with gamma-gamma coincidence.

    PubMed

    Toh, Y; Hatsukawa, Y; Oshima, M; Shinohara, N; Hayakawa, T; Kushita, K; Ueno, T

    2002-07-01

    129I is a long-lived (1.6 x 10(7) y) radionuclide that is produced in nature as the result of spontaneous fission of heavy elements and reaction of xenon with cosmic rays. Recently, however, artificial sources from nuclear power plants and nuclear test explosions have become a significant component of environmental radioactive iodine. Coincidence gamma-ray detection using Ge detectors makes it possible to simultaneously resolve the numerous gamma-rays produced by neutron activation. In this study, the coincidence gamma-ray detection technique was combined with neutron activation analysis to determine the radioactive iodine composition of seaweed. The ratio of 129I/127I in this common Japanese food item collected from the Ibaraki prefecture has been derived without the need for radiochemical purification. The isotopic ratio of 129I/127I in Kajime algae is 3.5(5) x 10(-10).

  14. Prompt Gamma Activation Analysis (PGAA): Technique of choice for nondestructive bulk analysis of returned comet samples

    NASA Technical Reports Server (NTRS)

    Lindstrom, David J.; Lindstrom, Richard M.

    1989-01-01

    Prompt gamma activation analysis (PGAA) is a well-developed analytical technique. The technique involves irradiation of samples in an external neutron beam from a nuclear reactor, with simultaneous counting of gamma rays produced in the sample by neutron capture. Capture of neutrons leads to excited nuclei which decay immediately with the emission of energetic gamma rays to the ground state. PGAA has several advantages over other techniques for the analysis of cometary materials: (1) It is nondestructive; (2) It can be used to determine abundances of a wide variety of elements, including most major and minor elements (Na, Mg, Al, Si, P, K, Ca, Ti, Cr, Mn, Fe, Co, Ni), volatiles (H, C, N, F, Cl, S), and some trace elements (those with high neutron capture cross sections, including B, Cd, Nd, Sm, and Gd); and (3) It is a true bulk analysis technique. Recent developments should improve the technique's sensitivity and accuracy considerably.

  15. 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

  16. Spectrum-based network visualization for topology analysis.

    PubMed

    Hu, Xianlin; Lu, Aidong; Wu, Xintao

    2013-01-01

    Network visualization techniques have been widely used to explore social networks, which are crucial to many application domains. A proposed visual-analytics approach provides functions that were previously hard to obtain. Based on recent achievements in spectrum-based analysis, it uses the features of node distribution and coordinates in the high-dimensional spectral space. Specifically, three-stage node projection and dispersion on a k-dimensional sphere in the spectral space determines the network layout. To assist interactive exploration of network topologies, network visualization and interactive analysis let users filter nodes and edges in a way that's meaningful to the global topology structure.

  17. Eigenvalue spectrum of the spheroidal harmonics: A uniform asymptotic analysis

    NASA Astrophysics Data System (ADS)

    Hod, Shahar

    2015-06-01

    The spheroidal harmonics Slm (θ ; c) have attracted the attention of both physicists and mathematicians over the years. These special functions play a central role in the mathematical description of diverse physical phenomena, including black-hole perturbation theory and wave scattering by nonspherical objects. The asymptotic eigenvalues {Alm (c) } of these functions have been determined by many authors. However, it should be emphasized that all the previous asymptotic analyzes were restricted either to the regime m → ∞ with a fixed value of c, or to the complementary regime | c | → ∞ with a fixed value of m. A fuller understanding of the asymptotic behavior of the eigenvalue spectrum requires an analysis which is asymptotically uniform in both m and c. In this paper we analyze the asymptotic eigenvalue spectrum of these important functions in the double limit m → ∞ and | c | → ∞ with a fixed m / c ratio.

  18. 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.

  19. 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

  20. 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).

  1. 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.

  2. 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.

  3. 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.

  4. 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).

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Application of multidimensional spectrum analysis for analytical chemistry

    SciTech Connect

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

    1999-11-16

    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.

  14. Gamma radiation shielding analysis of lead-flyash concretes.

    PubMed

    Singh, Kanwaldeep; Singh, Sukhpal; Dhaliwal, A S; Singh, Gurmel

    2014-11-04

    Six samples of lead-flyash concrete were prepared with lead as an admixture and by varying flyash content - 0%, 20%, 30%, 40%, 50% and 60% (by weight) by replacing cement and keeping constant w/c ratio. Different gamma radiation interaction parameters used for radiation shielding design were computed theoretically and measured experimentally at 662keV, 1173keV and 1332keV gamma radiation energy using narrow transmission geometry. The obtained results were compared with ordinary-flyash concretes. The radiation exposure rate of gamma radiation sources used was determined with and without lead-flyash concretes.

  15. Multiplex polymerase chain reaction-based deletion analysis of spontaneous, gamma ray- and alpha-induced hprt mutants of CHO-K1 cells.

    PubMed

    Schwartz, J L; Rotmensch, J; Sun, J; An, J; Xu, Z; Yu, Y; Hsie, A W

    1994-11-01

    Independent Chinese hamster ovary (CHO)-K1 cell mutants at the hypoxanthine-guanine phosphoribosyltransferase (hprt) locus were isolated from untreated, 60Co gamma ray- and 212Bi alpha-exposed cells and the genetic changes underlying the mutation determined by multiplex polymerase chain reaction (PCR)-based exon deletion analysis. In the 71 spontaneous mutants analyzed, 77.5% of the clones showed no change in exon number or size, 15.5% showed a loss of a single exon, 4.2% showed a loss of 2-8 exons, and 2.8% showed loss of all nine hprt exons (total gene deletion). Exposure to 6 Gy of gamma rays, which reduced survival levels to 10%, produced a significantly different deletion spectrum that was shifted toward deletions with 45% of the 20 mutants analyzed showing a loss of a single exon and 30% showing a loss of all nine exons. Exposure to 2 Gy alpha radiation from 212Bi, a 220Rn daughter, a dose which also reduced survival levels to about 10%, resulted in a deletion spectrum similar to the gamma-ray spectrum in that more than 75% of the 49 mutants analyzed were deletions. The alpha spectrum, however, was significantly different from both the spontaneous and gamma spectra with 55.1% of the alpha mutants showing a loss of all nine exons, 10.2% showing loss of a single exon, and 14.3% showing loss of 2-8 exons. Thus, alpha-radiation appears to produce larger intragenic deletions than gamma radiation. The results suggest that intragenic deletion size should be considered when low- and high linear energy transfer (LET) mutation spectra are compared.

  16. Polymerase chain reaction-deletion analysis of spontaneous, gamma ray-, and alpha-induced hprt mutants of CHO-K1 cells.

    SciTech Connect

    Schwartz, J. L.; Rotmensch, J.; Sun, J.; An, J.; Xu, Z.; Yu, Y.; Hsie, A. W.; Center for Mechanistic Biology and Biotechnology; Univ. of Chicago; Univ. of Texas Medical Branch

    1994-01-01

    Independent Chinese hamster ovary (CHO)-K1 cell mutants at the hypoxanthine-guanine phosphoribosyltransferase (hprt) locus were isolated from untreated, {sup 60}Co {gamma} ray-and {sup 212}Bi {alpha}-exposed cells and the genetic changes underlying the mutation determined by multiplex polymerase chain reaction (PCR)-based exon deletion analysis. In the 71 spontaneous mutants analyzed, 77.5% of the clones showed no change in exon number or size, 15.5% showed a loss of a single exon, 4.2% showed a loss of 2-8 exons, and 2.8% showed loss of all nine hprt exons (total gene deletion). Exposure to 6 Gy of {gamma} rays, which reduced survival levels to 10%, produced a significantly different deletion spectrum that was shifted toward deletions with 45% of the 20 mutants analyzed showing a loss of a single exon and 30% showing a loss of all nine exons. Exposure to 2 Gy {alpha} radiation from 212Bi, a 220Rn daughter, a dose which also reduced survival levels to about 10%, resulted in a deletion spectrum similar to the {gamma}-ray spectrum in that more than 75% of the 49 mutants analyzed were deletions. The {alpha} spectrum, however, was significantly different from both the spontaneous and {gamma} spectra with 55.1% of the {alpha} mutants showing a loss of all nine exons, 10.2% showing loss of a single exon, and 14.3% showing loss of 2-8 exons. Thus, {alpha}-radiation appears to produce larger intragenic deletions than {gamma} radiation. The results suggest that intragenic deletion size should be considered when low- and high linear energy transfer (LET) mutation spectra are compared.

  17. 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.

  18. 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.

  19. Bayesian Angular Power Spectrum Analysis of Interferometric Data

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

    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_p log n_p) where np 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.

  20. [The applications for Fourier transform infrared spectrum analysis technique in preventive medicine field].

    PubMed

    Yang, Jiao-lan; Luo, Tian

    2002-08-01

    This paper expatriated the applications for Fourier transform infrared spectrum analysis technique in preventive medicine field from four aspects of environmental pollution, life science, and the latest infrared analysis methods and near infrared analysis technique. In the environmental pollution field, it mainly described the advantages, the limitations and the solutions of the combined applications for gas chromatograph and Fourier transform infrared spectrum. In the life science field, it described the application for Fourier transform infrared spectrum analysis technique on protein secondary structure, membrane protein, phospholipid, nucleic acid, cell, tissue. In addition, it also introduced a few latest infrared analysis methods and the applications for near infrared spectrum analysis technique in food, cosmetic, drug.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Multicomponent analysis of total COS-B gamma-ray data at intermediate lattitudes

    NASA Technical Reports Server (NTRS)

    Strong, A. W.; Bloemen, J. B. G. M.; Hemsen, W.; Mayer-Hasselwander, H. A.

    1985-01-01

    The final COS-B database was used to study the gamma ray emission in the latitude range 10 deg /b/ 20 deg in terms of a four component model. The emissivity spectrum of the local interstellar medium is derived and compared with that found in previous studies. The intensity-Compton component is determined from the fitting procedure and is in good agreement with theoretical values.

  9. 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.

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

    SciTech Connect

    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) 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.

  11. 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

  12. Improved neutron-gamma discrimination for a {sup 6}Li-glass neutron detector using digital signal analysis methods

    SciTech Connect

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

    2016-01-15

    A {sup 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{sup 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 (a{sub 1}, b{sub 0}) 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.

  13. 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.

  14. 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.

  15. 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).

  16. Frequency spectrum analysis of finger photoplethysmographic waveform variability during haemodialysis.

    PubMed

    Javed, Faizan; Middleton, Paul M; Malouf, Philip; Chan, Gregory S H; Savkin, Andrey V; Lovell, Nigel H; Steel, Elizabeth; Mackie, James

    2010-09-01

    This study investigates the peripheral circulatory and autonomic response to volume withdrawal in haemodialysis based on spectral analysis of photoplethysmographic waveform variability (PPGV). Frequency spectrum analysis was performed on the baseline and pulse amplitude variabilities of the finger infrared photoplethysmographic (PPG) waveform and on heart rate variability extracted from the ECG signal collected from 18 kidney failure patients undergoing haemodialysis. Spectral powers were calculated from the low frequency (LF, 0.04-0.145 Hz) and high frequency (HF, 0.145-0.45 Hz) bands. In eight stable fluid overloaded patients (fluid removal of >2 L) not on alpha blockers, progressive reduction in relative blood volume during haemodialysis resulted in significant increase in LF and HF powers of PPG baseline and amplitude variability (P < 0.01), when expressed in mean-scaled units. The augmentation of LF powers in PPGV during haemodialysis may indicate the recovery and possibly further enhancement of peripheral sympathetic vascular modulation subsequent to volume unloading, whilst the increase in respiratory HF power in PPGV is most likely a sign of preload reduction. Spectral analysis of finger PPGV may provide valuable information on the autonomic vascular response to blood volume reduction in haemodialysis, and can be potentially utilized as a non-invasive tool for assessing peripheral circulatory control during routine dialysis procedure.

  17. Blind Extraction of an Exoplanetary Spectrum through Independent Component Analysis

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

    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 ~0.09 μm. 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.

  18. 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.

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

    SciTech Connect

    Cerdeño, D.G.; Peiró, M.; Robles, S. E-mail: miguel.peiro@uam.es

    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.

  20. 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.

  1. 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.

  2. 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.

  3. Interferon-gamma of the giant panda (Ailuropoda melanoleuca): complementary DNA cloning, expression, and phylogenetic analysis.

    PubMed

    Tao, Yaqiong; Zeng, Bo; Xu, Liu; Yue, Bisong; Yang, Dong; Zou, Fangdong

    2010-01-01

    Interferon-gamma (IFN-gamma) is the only member of type II IFN and is vital in the regulation of immune and inflammatory responses. Herein we report the cloning, expression, and sequence analysis of IFN-gamma from the giant panda (Ailuropoda melanoleuca). The open reading frame of this gene is 501 base pair in length and encodes a polypeptide consisting of 166 amino acids. All conserved N-linked glycosylation sites and cysteine residues among carnivores were found in the predicted amino acid sequence of the giant panda. Recombinant giant panda IFN-gamma with a V5 epitope and polyhistidine tag was expressed in HEK293 host cells and confirmed by Western blotting. Phylogenetic analysis of mammalian IFN-gamma-coding sequences indicated that the giant panda IFN-gamma was closest to that of carnivores, then to ungulates and dolphin, and shared a distant relationship with mouse and human. These results represent a first step into the study of IFN-gamma in giant panda.

  4. Code System for Isotope Identification by Gamma-Ray Analysis

    SciTech Connect

    1996-01-01

    For a set of a priori given nuclides taken from a work library, DIMEN uses median estimates of the peak areas and estimates of their errors to produce a list of possible nuclides matching a gamma-ray line and some measure of the reliability of this assignment.

  5. 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.

  6. Analysis of the COS B data for evidence of linear polarization of Vela pulsar gamma rays

    NASA Technical Reports Server (NTRS)

    Mattox, John R.; Mayer-Hasselwander, Hans A.; Strong, Andy W.

    1990-01-01

    The COS B spark chamber telescope observations of the Vela pulsar were analyzed for gamma-ray polarization. No significant quadrupole moment is found in the azimuthal distribution of the electron-positron pair production planes. However, analysis of the sensitivity indicates that even 100-percent polarization would not be detected. Therefore, the null result does not constrain the polarization of the Vela pulsar gamma-ray emission. This result contradicts the report of Caraveo et al. (1988) of possible evidence for polarization of the Vela pulsar gamma rays.

  7. Investigations on neutron-induced prompt gamma ray analysis of bulk samples.

    PubMed

    Dokhale, P A; Csikai, J; Oláh, L

    2001-06-01

    A systematic investigation was carried out for the improvement of the prompt gamma interrogation method used for contraband detection by the pulsed fast/thermal neutron analysis (PFTNA) technique. Optimizations of source detector shielding and geometry, role of the type and dimension of the gamma detector, attenuation of neutrons and gamma rays in bulky samples were also studied. Results obtained for both the shielding materials and elemental content of cocaine simulants have been compared with the values calculated by the MCNP-4A code.

  8. Theoretical analysis of spectrum flattening in fiber laser oscillator

    NASA Astrophysics Data System (ADS)

    Shi, Chen; Wang, Xiaolin; Zhou, Pu; Wang, Zefeng; Xu, Xiaojun; Lu, Qisheng

    2017-01-01

    The flatness of laser spectrum is important in many applications. In this manuscript, a method of acquiring flattened spectrum directly from a fiber oscillator by optimizing the reflective spectrum of Fiber Bragg Gratings (FBG) was demonstrated and optimized result at wavelength around 1064 nm and 1080 nm was presented. An optimization path to alter the reflectivity of FBGs using greedy algorithm was interpreted by analyzing the single-trip gain inside the resonant cavity. Our method has a guiding significance of controlling the output spectrum of laser oscillator using FBGs.

  9. 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.

  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. Improved singular spectrum analysis for time series with missing data

    NASA Astrophysics Data System (ADS)

    Shen, Y.; Peng, F.; Li, B.

    2015-07-01

    Singular spectrum analysis (SSA) is a powerful technique for time series analysis. Based on the property that the original time series can be reproduced from its principal components, this contribution develops an improved SSA (ISSA) for processing the incomplete time series and the modified SSA (SSAM) of Schoellhamer (2001) is its special case. The approach is evaluated with the synthetic and real incomplete time series data of suspended-sediment concentration from San Francisco Bay. The result from the synthetic time series with missing data shows that the relative errors of the principal components reconstructed by ISSA are much smaller than those reconstructed by SSAM. Moreover, when the percentage of the missing data over the whole time series reaches 60 %, the improvements of relative errors are up to 19.64, 41.34, 23.27 and 50.30 % for the first four principal components, respectively. Both the mean absolute error and mean root mean squared error of the reconstructed time series by ISSA are also smaller than those by SSAM. The respective improvements are 34.45 and 33.91 % when the missing data accounts for 60 %. The results from real incomplete time series also show that the standard deviation (SD) derived by ISSA is 12.27 mg L-1, smaller than the 13.48 mg L-1 derived by SSAM.

  12. Improved singular spectrum analysis for time series with missing data

    NASA Astrophysics Data System (ADS)

    Shen, Y.; Peng, F.; Li, B.

    2014-12-01

    Singular spectrum analysis (SSA) is a powerful technique for time series analysis. Based on the property that the original time series can be reproduced from its principal components, this contribution will develop an improved SSA (ISSA) for processing the incomplete time series and the modified SSA (SSAM) of Schoellhamer (2001) is its special case. The approach was evaluated with the synthetic and real incomplete time series data of suspended-sediment concentration from San Francisco Bay. The result from the synthetic time series with missing data shows that the relative errors of the principal components reconstructed by ISSA are much smaller than those reconstructed by SSAM. Moreover, when the percentage of the missing data over the whole time series reaches 60%, the improvements of relative errors are up to 19.64, 41.34, 23.27 and 50.30% for the first four principal components, respectively. Besides, both the mean absolute errors and mean root mean squared errors of the reconstructed time series by ISSA are also much smaller than those by SSAM. The respective improvements are 34.45 and 33.91% when the missing data accounts for 60%. The results from real incomplete time series also show that the SD derived by ISSA is 12.27 mg L-1, smaller than 13.48 mg L-1 derived by SSAM.

  13. Localizing heart sounds in respiratory signals using singular spectrum analysis.

    PubMed

    Ghaderi, Foad; Mohseni, Hamid R; Sanei, Saeid

    2011-12-01

    Respiratory sounds are always contaminated by heart sound interference. An essential preprocessing step in some of the heart sound cancellation methods is localizing primary heart sound components. Singular spectrum analysis (SSA), a powerful time series analysis technique, is used in this paper. Despite the frequency overlap of the heart and lung sound components, two different trends in the eigenvalue spectra are recognizable, which leads to find a subspace that contains more information about the underlying heart sound. Artificially mixed and real respiratory signals are used for evaluating the performance of the method. Selecting the appropriate length for the SSA window results in good decomposition quality and low computational cost for the algorithm. The results of the proposed method are compared with those of well-established methods, which use the wavelet transform and entropy of the signal to detect the heart sound components. The proposed method outperforms the wavelet-based method in terms of false detection and also correlation with the underlying heart sounds. Performance of the proposed method is slightly better than that of the entropy-based method. Moreover, the execution time of the former is significantly lower than that of the latter.

  14. 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. PMID:27818695

  15. 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.

  16. Spectrum image analysis tool - A flexible MATLAB solution to analyze EEL and CL spectrum images.

    PubMed

    Schmidt, Franz-Philipp; Hofer, Ferdinand; Krenn, Joachim R

    2017-02-01

    Spectrum imaging techniques, gaining simultaneously structural (image) and spectroscopic data, require appropriate and careful processing to extract information of the dataset. In this article we introduce a MATLAB based software that uses three dimensional data (EEL/CL spectrum image in dm3 format (Gatan Inc.'s DigitalMicrograph(®))) as input. A graphical user interface enables a fast and easy mapping of spectral dependent images and position dependent spectra. First, data processing such as background subtraction, deconvolution and denoising, second, multiple display options including an EEL/CL moviemaker and, third, the applicability on a large amount of data sets with a small work load makes this program an interesting tool to visualize otherwise hidden details.

  17. 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).

  18. 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.

  19. The Marshall Space Flight Center development of mirror modules for the ART-XC instrument aboard the Spectrum-Roentgen-Gamma mission

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

    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 cm2 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.

  20. 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.

  1. Multivariate singular spectrum analysis and the road to phase synchronization

    NASA Astrophysics Data System (ADS)

    Groth, Andreas; Ghil, Michael

    2010-05-01

    Singular spectrum analysis (SSA) and multivariate SSA (M-SSA) are based on the classical work of Kosambi (1943), Loeve (1945) and Karhunen (1946) and are closely related to principal component analysis. They have been introduced into information theory by Bertero, Pike and co-workers (1982, 1984) and into dynamical systems analysis by Broomhead and King (1986a,b). Ghil, Vautard and associates have applied SSA and M-SSA to the temporal and spatio-temporal analysis of short and noisy time series in climate dynamics and other fields in the geosciences since the late 1980s. M-SSA provides insight into the unknown or partially known dynamics of the underlying system by decomposing the delay-coordinate phase space of a given multivariate time series into a set of data-adaptive orthonormal components. These components can be classified essentially into trends, oscillatory patterns and noise, and allow one to reconstruct a robust "skeleton" of the dynamical system's structure. For an overview we refer to Ghil et al. (Rev. Geophys., 2002). In this talk, we present M-SSA in the context of synchronization analysis and illustrate its ability to unveil information about the mechanisms behind the adjustment of rhythms in coupled dynamical systems. The focus of the talk is on the special case of phase synchronization between coupled chaotic oscillators (Rosenblum et al., PRL, 1996). Several ways of measuring phase synchronization are in use, and the robust definition of a reasonable phase for each oscillator is critical in each of them. We illustrate here the advantages of M-SSA in the automatic identification of oscillatory modes and in drawing conclusions about the transition to phase synchronization. Without using any a priori definition of a suitable phase, we show that M-SSA is able to detect phase synchronization in a chain of coupled chaotic oscillators (Osipov et al., PRE, 1996). Recently, Muller et al. (PRE, 2005) and Allefeld et al. (Intl. J. Bif. Chaos, 2007) have

  2. 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.

  3. A Lingering Non-thermal Component in the Gamma-Ray Burst Prompt Emission: Predicting GeV Emission from the MeV Spectrum

    NASA Astrophysics Data System (ADS)

    Basak, Rupal; Rao, A. R.

    2013-09-01

    The high-energy GeV emission of gamma-ray bursts (GRBs) detected by Fermi/LAT has a significantly different morphology compared to the lower energy MeV emission detected by Fermi/GBM. Though the late-time GeV emission is believed to be synchrotron radiation produced via an external shock, this emission as early as the prompt phase is puzzling. A meaningful connection between these two emissions can be drawn only by an accurate description of the prompt MeV spectrum. We perform a time-resolved spectroscopy of the Gamma-ray Burst Monitor (GBM) data of long GRBs with significant GeV emission, using a model consisting of two blackbodies and a power law. We examine in detail the evolution of the spectral components and find that GRBs with high GeV emission (GRB 090902B and GRB 090926A) have a delayed onset of the power-law component in the GBM spectrum, which lingers at the later part of the prompt emission. This behavior mimics the flux evolution in the Large Area Telescope (LAT). In contrast, bright GBM GRBs with an order of magnitude lower GeV emission (GRB 100724B and GRB 091003) show a coupled variability of the total and the power-law flux. Further, by analyzing the data for a set of 17 GRBs, we find a strong correlation between the power-law fluence in the MeV and the LAT fluence (Pearson correlation: r = 0.88 and Spearman correlation: ρ = 0.81). We demonstrate that this correlation is not influenced by the correlation between the total and the power-law fluences at a confidence level of 2.3σ. We speculate the possible radiation mechanisms responsible for the correlation.

  4. 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%)

  5. 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.

  6. c-GAMMA:Comparative Genome Analysis of Molecular Markers

    NASA Astrophysics Data System (ADS)

    Peterlongo, Pierre; Nicolas, Jacques; Lavenier, Dominique; Vorc'h, Raoul; Querellou, Joël

    Discovery of molecular markers for efficient identification of living organisms remains a challenge of high interest. The diversity of species can now be observed in details with low cost genomic sequences produced by new generation of sequencers. A method, called c-GAMMA, is proposed. It formalizes the design of new markers for such data. It is based on a series of filters on forbidden pairs of words, followed by an optimization step on the discriminative power of candidate markers.

  7. Whether the Autism Spectrum Quotient consists of two different subgroups? Cluster analysis of the Autism Spectrum Quotient in general population.

    PubMed

    Kitazoe, Noriko; Fujita, Naofumi; Izumoto, Yuji; Terada, Shin-Ichi; Hatakenaka, Yuhei

    2017-04-01

    The purpose of this study was to investigate whether the individuals in the general population with high scores on the Autism Spectrum Quotient constituted a single homogeneous group or not. A cohort of university students (n = 4901) was investigated by cluster analysis based on the original five subscales of the Autism Spectrum Quotient. Based on the results of the analysis, the students could be divided into six clusters: the first with low scores on all the five subscales, the second with high scores on only the 'attention to detail' subscale, the third and fourth with intermediate scores on all the subscales, the fifth with high scores on four of the five subscales but low scores on the 'attention to detail' subscale and the sixth with high scores on all the five subscales. The students with high total Autism Spectrum Quotient scores (n = 166) were divided into two groups: one with high scores on four subscales but low scores on the 'attention to detail' subscale and the other with high scores on all the five subscales. The results of this study suggested that individuals from the general population with high Autism Spectrum Quotient scores may consist of two qualitatively different groups.

  8. 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).

  9. Lines and boxes: Unmasking Dynamical Dark Matter through correlations in the MeV gamma-ray spectrum

    NASA Astrophysics Data System (ADS)

    Boddy, Kimberly K.; Dienes, Keith R.; Kim, Doojin; Kumar, Jason; Park, Jong-Chul; Thomas, Brooks

    2016-11-01

    Identifying signatures of dark matter at indirect-detection experiments is generally more challenging for scenarios involving nonminimal dark sectors such as Dynamical Dark Matter (DDM) than for scenarios involving a single dark particle. This additional difficulty arises because the partitioning of the total dark-matter abundance across an ensemble of different constituent particles with different masses tends to "smear" the injection spectra of photons and other cosmic-ray particles that are produced via dark-matter annihilation or decay. As a result, the imprints of the dark sector on these cosmic-ray flux spectra typically take the form of continuum features rather than sharp peaks or lines. In this paper, however, we identify an unambiguous signature of nonminimal dark sectors such as DDM which can overcome these issues and potentially be observed at gamma-ray telescopes operating in the MeV range. We discuss the specific situations in which this signature can arise, and demonstrate that this signature can be exploited in order to significantly enhance our ability to resolve the unique spectral features of DDM and other nonminimal dark sectors at future gamma-ray facilities.

  10. 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.

  11. 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.

  12. Multiple spectrum analysis and evaluation for optical constants of HfO2 thin films

    NASA Astrophysics Data System (ADS)

    Liu, Dandan; Liu, Huasong; Jiang, Chenghui; Jiang, Yugang; Wang, Lishuan; Zhao, Zhihong; Ji, Yiqin

    2014-08-01

    HfO2 thin films were deposited on ZS1 silica by Ion Beam Sputtering (IBS) technique. Optical constants of HfO2 thin films were obtained by multiple spectrum analysis method, which combined the transmittance spectrum and ellipsometry spectrum of the film. The refractive index and extinction coiefficient of HfO2 thin films were evaluated by etching experiments of the film. The analysis spectral range was between 250nm and 850nm.

  13. 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.

  14. 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.

  15. Blind Extraction and Security Analysis of Spread Spectrum Hidden Watermarks

    DTIC Science & Technology

    2012-04-01

    1725-1731, Oct. 2000. [6] Gkizeli, M., and Pados, D. A., "Image-adaptive spread-spectrum steganography ,’’ Proc. 38th Conf. on Information Sciences and...Signature Design for Spread-Spectrum Steganography ," IEEE Transactions on Image Processing, vol. 16, no.2, pp.391-405, Feb. 2007. [9] Wei, L., Pados, D...A., Batalama, S. N., and Medley, M. J., ‘‘Sum-SINR/sum-capacity optimal multisignature spread-spectrum steganography ,’’ in Proc. SPIE Mobile

  16. A new gamma-ray detector, 3-dimension, fast scanning table for pulse-shape analysis

    SciTech Connect

    Ginsz, M.; Duchene, G.; Didierjean, F.; Filliger, M.; Sigward, M.-H.; Pirard, B.

    2015-07-01

    The state-of-the art gamma-ray spectrometers such as AGATA and GRETA are using position sensitive multi-segmented HPGe crystals. Pulse-shape analysis (PSA) allows to retrieve the localisation of the gamma interactions and to perform gamma-ray tracking within germanium. The precision of the localisation depends on the quality of the pulse-shape database used for comparison. The IPHC laboratory developed a new fast scanning table allowing to measure experimental pulse shapes in the whole volume of any crystal. The results of the scan of an AGATA 36-fold segmented tapered coaxial detector are shown here, 48580 experimental pulse shapes are extracted within 2 weeks of scanning. These data will contribute to AGATA PSA performances, but have also applications for gamma cameras or Compton-suppressed detectors. (authors)

  17. Performance analysis of free space optical system with spatial modulation and diversity combiners over the Gamma Gamma atmospheric turbulence

    NASA Astrophysics Data System (ADS)

    Odeyemi, Kehinde O.; Owolawi, Pius A.; Srivastava, Viranjay M.

    2017-01-01

    Atmospheric turbulence is a major impairment that degrades the performance of free space optical (FSO) communication systems. Spatial modulation (SM) with receive spatial diversity is considered as a powerful technique to mitigate the fading effect induced by atmospheric turbulence. In this paper, the performance of free space optical spatial modulation (FSO-SM) system under Gamma-Gamma atmospheric turbulence is presented. We studied the Average Bit Error Rate (ABER) for the system by employing spatial diversity combiners such Maximum Ratio Combining (MRC) and Equal Gain Combining (EGC) at the receiving end. In particular, we provide a theoretical framework for the system error by deriving Average Pairwise Error Probability (APEP) expression using a generalized infinite power series expansion approach and union bounding technique is applied to obtain the ABER for each combiner. Based on this study, it was found that spatial diversity combiner significantly improved the system error rate where MRC outperforms the EGC. The performance of this system is also compared with other well established diversity combiner systems. The proposed system performance is further improved by convolutional coding technique and our analysis confirmed that the system performance of MRC coded system is enhanced by approximately 20 dB while EGC falls within 17 dB.

  18. 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.

  19. 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.

  20. [A Composition Analysis Method of Mixed Pigments Based on Spectrum Expression and Independent Component Analysis].

    PubMed

    Wang, Gong-ming; Liu, Zhi-yong

    2015-06-01

    Reflectance spectrometry is a common method in composition analysis of mixed pigments. In this method, similarity is used to determine the type of basic pigments that constitute the mixed pigments. But its result may be inaccurate because it is easily influenced by a variety of basic pigments. In this study, a composition analysis method of mixed pigments based on spectrum expression and independent component analysis is proposed, and the composition of mixed pigments can be calculated accurately. First of all, the spectral information of mixed pigments is obtained with spectrometer, and is expressed as the discrete signal. After that, the spectral information of basic pigments is deduced with independent component analysis. Then, the types of basic pigments are determined by calculating the spectrum similarity between the basic pigments and known pigments. Finally, the ratios of basic pigments are obtained by solving the Kubelka-Munk equation system. In addition, the simulated spectrum data of Munsell color card is used to validate this method. The compositions of mixed pigments from three basic pigments are determined under the circumstance of normality and disturbance. And the compositions of mixture from several pigments within the set of eight basic pigments are deduced successfully. The curves of separated pigment spectrums are very similar to the curves of original pigment spectrums. The average similarity is 97.72%, and the maximum one can reach to 99.95%. The calculated ratios of basic pigments close to the original one. It can be seen that this method is suitable for composition analysis of mixed pigments.

  1. 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.

  2. 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.

  3. Analysis of gamma-ray burst spectra with cyclotron lines

    NASA Technical Reports Server (NTRS)

    Kargatis, Vincent; Liang, Edison P.

    1992-01-01

    Motivated by the recent developments in the cyclotron resonance upscattering of soft photons or CUSP model of Gamma Ray Burst (GBR) continuum spectra, we revisit a select database of GRBs with credible cyclotron absorption features. We measure the break energy of the continuum, the slope below the break and deduce the soft photon energy or the electron beam Lorentz factor cutoff. We study the correlation (or lack of) between various parameters in the context of the CUSP model. One surprise result is that there appears to be marginal correlation between the break energy and the spectral index below the break.

  4. 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.

  5. 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.

  6. 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.

  7. Channelized broadband signal spectrum analysis based on weighted overlap-add structure.

    PubMed

    Guo, Lianping; Jiang, Jun; Tan, Feng; Pan, Huiqing; Zhang, Peng; Zeng, Hao; Bai, Lihong

    2016-10-01

    The digital channelization technology has been applied in many electronic areas, and the real-time broadband spectrum analysis has been the research hotspot in the area of signal processing. This paper introduces the channelized broadband signal spectrum analysis method. Based on the weighted overlap-add (WOLA) structure, this method divides the input broadband signal into several sub-bands or channels, and then downconverts and decimates the sub-band signals to obtain the baseband signals with a low sampling rate. The spectrum analysis results of the input broadband signal are achieved by conducting further decimation, fast Fourier transform and spectrum splicing to the baseband signals. The Matlab simulation results verify the correctness of the WOLA structure, and finally, an experimental platform is designed in detail to verify the practicability of this broadband spectrum analysis method.

  8. [Chlorophyll fluorescence spectrum analysis of greenhouse cucumber disease and insect damage].

    PubMed

    Sui, Yuan-yuan; Yu, Hai-ye; Zhang, Lei; Luo, Han; Ren, Shun; Zhao, Guo-gang

    2012-05-01

    The present paper is based on chlorophyll fluorescence spectrum analysis. The wavelength 685 nm was determined as the primary characteristic point for the analysis of healthy or disease and insect damaged leaf by spectrum configuration. Dimensionality reduction of the spectrum was achieved by combining simple intercorrelation bands selection and principal component analysis (PCA). The principal component factor was reduced from 10 to 5 while the spectrum information was kept reaching 99.999%. By comparing and analysing three modeling methods, namely the partial least square regression (PLSR), BP neural network (BP) and least square support vector machine regression (LSSVMR), regarding correlation coefficient of true value and predicted value as evaluation criterion, eventually, LSSVMR was confirmed as the appropriate method for modeling of greenhouse cucumber disease and insect damage chlorophyll fluorescence spectrum analysis.

  9. Channelized broadband signal spectrum analysis based on weighted overlap-add structure

    NASA Astrophysics Data System (ADS)

    Guo, Lianping; Jiang, Jun; Tan, Feng; Pan, Huiqing; Zhang, Peng; Zeng, Hao; Bai, Lihong

    2016-10-01

    The digital channelization technology has been applied in many electronic areas, and the real-time broadband spectrum analysis has been the research hotspot in the area of signal processing. This paper introduces the channelized broadband signal spectrum analysis method. Based on the weighted overlap-add (WOLA) structure, this method divides the input broadband signal into several sub-bands or channels, and then downconverts and decimates the sub-band signals to obtain the baseband signals with a low sampling rate. The spectrum analysis results of the input broadband signal are achieved by conducting further decimation, fast Fourier transform and spectrum splicing to the baseband signals. The Matlab simulation results verify the correctness of the WOLA structure, and finally, an experimental platform is designed in detail to verify the practicability of this broadband spectrum analysis method.

  10. 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

  11. Analysis of the backscatter spectrum in an ionospheric modification experiment

    NASA Technical Reports Server (NTRS)

    Kim, H.

    1973-01-01

    Predictions of the backscatter spectrum are compared, including effects of ionospheric inhomogeneity with experimental observations of incoherent backscatter from an artificially heated region. Calculations show that the strongest backscatter echo received is not, in fact, from the reflection level, but from a region some distance below (about 0.5 km for an experiment carried out at Arecibo), where the pump wave from a HF transmitter approximately 100 kW) is below the threshold for parametric amplification. By taking the standing wave pattern of the pump into account, asymmetry is explained of the up-shifted and down-shifted plasma lines in the backscatter spectrum, and the several peaks typically observed in the region of the spectrum near the HF transmitter frequency.

  12. 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.

  13. HESS J1427-608: An Unusual Hard, Unbroken Gamma-Ray Spectrum in a Very Wide Energy Range

    NASA Astrophysics Data System (ADS)

    Guo, Xiao-Lei; Xin, Yu-Liang; Liao, Neng-Hui; Yuan, Qiang; Gao, Wei-Hong; He, Hao-Ning; Fan, Yi-Zhong; Liu, Si-Ming

    2017-01-01

    We report the detection of a GeV γ-ray source that spatially overlaps and is thus very likely associated with the unidentified very high energy (VHE) γ-ray source HESS J1427‑608 with the Pass 8 data recorded by the Fermi Large Area Telescope. The photon spectrum of this source is best described by a power law with an index of 1.85 ± 0.17 in the energy range of 3–500 GeV, and the measured flux connects smoothly with that of HESS J1427‑608 at a few hundred gigaelectronvolts. This source shows no significant extension and time variation. The broadband GeV to TeV emission over four decades of energies can be well fitted by a single power-law function with an index of 2.0, without obvious indication of spectral cutoff toward high energies. Such a result implies that HESS J1427‑608 may be a PeV particle accelerator. We discuss the possible nature of HESS J1427‑608 according to the multiwavelength spectral fittings. Given the relatively large errors, either a leptonic or a hadronic model can explain the multiwavelength data from radio to VHE γ-rays. The inferred magnetic field strength is a few micro-Gauss, which is smaller than the typical values of supernova remnants (SNRs) and is consistent with some pulsar wind nebulae (PWNe). On the other hand, the flat γ-ray spectrum is slightly different from typical PWNe but is similar to that of some known SNRs.

  14. 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.

  15. Feasibility study of plutonium isotopic analysis of resin beads by nondestructive gamma-ray spectroscopy

    SciTech Connect

    Li, T.K.

    1985-01-01

    We have initiated a feasibility study on the use of nondestructive low-energy gamma-ray spectroscopy for plutonium isotopic analysis on resin beads. Seven resin bead samples were measured, with each sample containing an average of 9 ..mu..g of plutonium; the isotopic compositions of the samples varied over a wide range. The gamma-ray spectroscopy results, obtained from 4-h counting-time measurements, were compared with mass spectrometry results. The average ratios of gamma-ray spectroscopy to mass spectrometry were 1.014 +- 0.025 for /sup 238/Pu//sup 239/Pu, 0.996 +- 0.018 for /sup 240/Pu//sup 239/Pu, and 0.980 +- 0.038 for /sup 241/Pu//sup 239/Pu. The rapid, automated, and accurate nondestructive isotopic analysis of resin beads may be very useful to process technicians and International Atomic Energy Agency inspectors. 3 refs., 1 fig., 3 tabs.

  16. Development of a correction method for the time-of-flight prompt gamma-ray analysis

    NASA Astrophysics Data System (ADS)

    Huang, M.; Toh, Y.; Ebihara, M.; Kimura, A.; Nakamura, S.

    2017-03-01

    A new analytical technique, time-of-flight prompt gamma-ray analysis, has been developed at the Japan Proton Accelerator Research Complex. In order to apply it to accurate elemental analysis, a set of Fe and Au reference samples were measured to examine the several factors which affect the number of detected events. It was found that major contributing factors included attenuations of neutrons and gamma rays in the sample, live-time fraction and signal pile-up correction. A simulation model was built for the estimation of neutron and gamma-ray attenuations. A simple empirical formula was proposed to calculate the signal pile-up correction factor. The whole correction method has proven to be accurate and reliable.

  17. 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).

  18. 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.

  19. 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.…

  20. Factor Analysis of the Autism Spectrum Screening Questionnaire

    ERIC Educational Resources Information Center

    Posserud, Britt; Lundervold, Astri J.; Steijnen, Maaike C.; Verhoeven, Sophie; Stormark, Kjell Morten; Gillberg, Christopher

    2008-01-01

    The present study investigated the factor structure of parent and teacher Autism Spectrum Screening Questionnaire (ASSQ) in a population of 7-9 years old children. For validation purposes, factors derived were correlated with results on the Strengths and Difficulties Questionnaire (SDQ). A three-factor solution was identified on both parent and…

  1. DoD Spectrum Management: A Critical Analysis

    DTIC Science & Technology

    2008-06-01

    29  13. IRAC Council...Administration (NTIA) Interdepartmental Radio Advisory Committee ( IRAC ). Each nation manages its own spectrum bands in a similar manner since the...Services continue to work with NTIA and the IRAC Frequency Assignment Subcommittee (FAS) to reduce the processing times. Figure 4 Frequency

  2. Rotational Doppler shift for electromagnetic waves carrying orbital angular momentum based on spectrum analysis

    NASA Astrophysics Data System (ADS)

    Yang, Tao; Wang, Gang

    2017-03-01

    We investigate the rotational Doppler effect for the electromagnetic wave carrying orbital angular momentum (OAM) with a method based on spectrum analysis, which is appropriate for both optics and free-space radio cases. We find that the frequency spectrum received is the convolution of emission spectrum and a discrete spectrum about OAM states, and verify it in the numerical simulations as well. This discovery makes it possible to distinguish the linear and rotational Doppler shift, and is helpful to developments of remote sensing and velocimetry in radar.

  3. [Research on the method of copper converting process determination based on emission spectrum analysis].

    PubMed

    Li, Xian-xin; Liu, Wen-qing; Zhang, Yu-jun; Si, Fu-qi; Dou, Ke; Wang, Feng-ping; Huang, Shu-hua; Fang, Wu; Wang, Wei-qiang; Huang, Yong-feng

    2012-05-01

    A method of copper converting process determination based on PbO/PbS emission spectrum analysis was described. According to the known emission spectrum of gas molecules, the existence of PbO and PbS was confirmed in the measured spectrum. Through the field experiment it was determined that the main emission spectrum of the slag stage was from PbS, and the main emission spectrum of the copper stage was from PbO. The relative changes in PbO/PbS emission spectrum provide the method of copper converting process determination. Through using the relative intensity in PbO/PbS emission spectrum the copper smelting process can be divided into two different stages, i.e., the slag stage (S phase) and the copper stage (B phase). In a complete copper smelting cycle, a receiving telescope of appropriate view angle aiming at the converter flame, after noise filtering on the PbO/PbS emission spectrum, the process determination agrees with the actual production. Both the theory and experiment prove that the method of copper converting process determination based on emission spectrum analysis is feasible.

  4. 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.

  5. ART-XC: a medium-energy x-ray telescope system for the Spectrum-R-Gamma mission

    NASA Astrophysics Data System (ADS)

    Arefiev, V.; Pavlinsky, M.; Lapshov, I.; Tkachenko, A.; Sazonov, S.; Revnivtsev, M.; Semena, N.; Buntov, M.; Vikhlinin, A.; Gubarev, M.; O'Dell, S.; Ramsey, B.; Romaine, S.; Swartz, D.; Weisskopf, M.; Hasinger, G.; Predehl, P.; Grigorovich, S.; Litvin, D.; Meidinger, N.; Strüder, L. W.

    2008-07-01

    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 the detection of X-ray photons up to 15 keV. The field of view of the individual mirror module is about 18×18 arcminutes2 and the sensitivity of the ART-XC system for 4 years of survey will be better than 10-12 erg s-1 cm-2 over the 4-12 keV energy band. This will allow the ART-XC instrument to discover several thousands new AGNs.

  6. 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.

  7. 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,…

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

    SciTech Connect

    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.

  9. 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...

  10. 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.

  11. 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.

  12. Analysis of gamma-ray dosimetry experiments in the zero power MINERVE facility

    SciTech Connect

    Amharrak, H.; Di Salvo, J.; Lyoussi, A.; Roche, A.; Masson-Fauchier, M.; Bosq, J. C.; Carette, M.

    2011-07-01

    The objective of this study is to develop nuclear heating measurement methods in zero power experimental reactors. These developments contribute to the qualification of photonics calculation schemes for the assessment of gamma heating in the future Jules Horowitz Material Testing Reactor. This paper presents the analysis of thermoluminescent detector (TLD) experiments in the UO{sub 2} core of the MINERVE Research Reactor at the French Alternative Energies and Atomic Energy Commission center in Cadarache. The experimental sources of uncertainty in the gamma dose have been reduced by improving the measurement conditions and the repeatability of the calibration step for each individual TLD. The interpretation of these measurements needs to take into account the calculation of cavity correction factors related to calibration and irradiation configurations, as well as neutron correction calculations. These calculations are based on Monte Carlo simulations of neutron-gamma and gamma-electron transport coupled particles. The comparison between calculated and measured integral gamma-ray absorbed doses in the aluminum material surrounding the TLD shows that calculations slightly overestimate the measurement, with a calculated versus experimental ratio equal to 1.04 {+-} 5.7 % (k=2). (authors)

  13. Analysis of Neutron Induced Gamma Activity in Lowbackground Ge - Spectroscopy Systems

    NASA Astrophysics Data System (ADS)

    Jovančević, Nikola; Krmar, Midrag

    Neutron interactions with materials of Ge-spectroscopy systems are one of the main sources of background radiation in low-level gamma spectroscopy measurements. Because of that detailed analysis of neutron induced gamma activity in low-background Ge-spectroscopy systems was done. Two HPGe detectors which were located in two different passive shields: one in pre-WW II made iron and the second in commercial low background lead were used in the experiment. Gamma lines emitted after neutron capture, as well as after inelastic scattering on the germanium crystal and shield materials (lead, iron, hydrogen, NaI) were detected and then analyzed. The thermal and fast neutron fluxes were calculated and their values were compared for the two different kinds of detector shield. The relative intensities of several gamma lines emitted after the inelastic scattering of neutrons (created by cosmic muons) in 56Fe were report. These relative intensities of detected gamma lines of 56Fe are compared with the results collected in the same iron shield by the use of the 252Cf neutrons.

  14. 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).

  15. 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

  16. 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.

  17. Photoacoustic spectrum analysis for microstructure characterization in biological tissue: A feasibility study

    NASA Astrophysics Data System (ADS)

    Xu, Guan; Dar, Irfaan A.; Tao, Chao; Liu, Xiaojun; Deng, Cheri X.; Wang, Xueding

    2012-11-01

    This study investigates the feasibility of characterizing the microstructures within a biological tissue by analyzing the frequency spectrum of the photoacoustic signal from the tissue. Hypotheses are derived from theoretical analyses on the relationships between the dimensions/concentrations of the photoacoustic sources within the region-of-interest and the linear model fitted to the power spectra of photoacoustic signals. The hypotheses are validated, following the procedures of ultrasound spectrum analysis, by simulations and experiments with phantoms fabricated by embedding the polyethylene microspheres in porcine gelatin, indicating that photoacoustic spectrum analysis could be a potential tool for characterizing microstructures in biological samples.

  18. Photoacoustic spectrum analysis for microstructure characterization in biological tissue: A feasibility study.

    PubMed

    Xu, Guan; Dar, Irfaan A; Tao, Chao; Liu, Xiaojun; Deng, Cheri X; Wang, Xueding

    2012-11-26

    This study investigates the feasibility of characterizing the microstructures within a biological tissue by analyzing the frequency spectrum of the photoacoustic signal from the tissue. Hypotheses are derived from theoretical analyses on the relationships between the dimensions/concentrations of the photoacoustic sources within the region-of-interest and the linear model fitted to the power spectra of photoacoustic signals. The hypotheses are validated, following the procedures of ultrasound spectrum analysis, by simulations and experiments with phantoms fabricated by embedding the polyethylene microspheres in porcine gelatin, indicating that photoacoustic spectrum analysis could be a potential tool for characterizing microstructures in biological samples.

  19. 2-D Acousto-Optic Signal Processors for Simultaneous Spectrum Analysis and Direction Finding

    DTIC Science & Technology

    1990-11-01

    National Dfense Defence nationale 2-D ACOUSTO - OPTIC SIGNAL PROCESSORS FOR SIMULTANEOUS SPECTRUM ANALYSIS 00 AND DIRECTION FINDING (U) by NM Jim P.Y...Wr pdft .1w I0~1111191 3 05089 National DIfense Defence nationale 2-D ACOUSTO - OPTIC SIGNAL PROCESSORS FOR SIMULTANEOUS SPECTRUM ANALYSIS AND DIRECTION...Processing, J.T. Tippet et al., Eds., Chapter 38, pp. 715-748, MIT Press, Cambridge 1965. [6] A.E. Spezio," Acousto - optics for Electronic Warfare

  20. Analysis and Interpretation of Gamma-Ray Burst Continuum Spectral Evolution with BATSE Data

    NASA Astrophysics Data System (ADS)

    Crider, Anthony Wayne

    1999-10-01

    Once a day, a flash of gamma-rays erupts somewhere in space and is detected by an international fleet of satellites. Since their first detection over a quarter century ago, these gamma-ray bursts have puzzled researchers who could not determine their distance, emission mechanism, or progenitor. Much of this confusion arose as theorists attempted to create a single model to explain what we now believe are at least two, and probably more, populations of gamma-ray transients. Within the past two years, thanks largely to the Dutch-Italian satellite BeppoSAX, astronomers discovered that bursts have multiwavelength fading afterglows. This helped them determine that most gamma-ray bursts are from distant galaxies. However, it did not answer the questions regarding the emission mechanism or the progenitor. We place constraints on the emission mechanism by closely examining the spectral evolution of gamma-ray bursts observed by the American instrument BATSE. From a sample of 41 distinct pulses in 26 bright gamma-ray bursts, we have determined that the pulses appear to be radiatively cooling. We also studied the evolving spectral shape in 79 bursts. In particular, we found that both the range and evolution of the spectral index below the spectral break conflict with the predictions of a popular synchrotron shock model. They instead suggest inverse Comptonization in a hybrid thermal plus nonthermal plasma as the emission mechanism. With our Monte Carlo codes, we have begun the generation of a library of inverse Compton spectra. Using them, we have made preliminary fits to two bursts with prompt multiwavelength data. The characteristic "terrace-shaped" Compton spectrum is evident in both using BATSE data alone. This shape appears to be confirmed for the January 1, 1997 burst using BeppoSAX X-ray data and for the January 23, 1999 burst using optical data from the ground-based robotic telescope, ROTSE. Both bursts appear to be enshrouded in a material with a high initial Thomson

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

    PubMed

    Kavetskiy, A; Yakubova, G; Torbert, H A; Prior, S A

    2015-02-01

    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 produced measurements in agreement with theoretical considerations. The continuous NGA mode was twice as fast and just as accurate as the pulse mode, thus this mode was preferable for routine soil carbon analysis.

  2. Feasibility study for the quantification of total protein content by multiple prompt gamma-ray analysis.

    PubMed

    Toh, Y; Murakami, Y; Furutaka, K; Kimura, A; Koizumi, M; Hara, K; Kin, T; Nakamura, S; Harada, H

    2012-06-01

    Protein is an important nutrient in foods. The classical nitrogen analysis method is the Kjeldahl technique, which is time-consuming and inconvenient. As a convenient method to quantify protein content in biological samples, the feasibility of application of multiple prompt gamma-ray analysis (MPGA) to the quantification was studied. Results for protein content are reported for several reference materials and prove the method to be reliable.

  3. SPRT Analysis of Anomalies in Tritium Beta Decay Spectrum

    NASA Astrophysics Data System (ADS)

    Goldman, T.; Stephenson, G. J., Jr.

    1997-10-01

    The experimentally observed deviations from the Kurie plot near the endpoint of Tritium beta decay are opposite to those expected for the case of massive neutrinos. We reexamine(O. Kofoed-Hansen, Phil. Mag. 42), 1448 (1951). the possibility that these deviations are due to new hypoweak interactions. We find that enhancement above the massless neutrino beta spectrum does occur for all cases (scalar, pseudoscalar, tensor or right-handed currents), although it apparently cannot be large enough to explain the data and be consistent with other experimental constraints. Bounds on the strength of these non-standard model interactions are derived.

  4. 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.

  5. Molecular diagnosis of A gamma hereditary persistence of fetal hemoglobin using polymerase chain reaction and oligonucleotide analysis.

    PubMed

    Gottardi, E; Alfarano, A; Serra, A; Sciarratta, G; Bertero, M T; Saglio, G; Camaschella, C

    1990-01-01

    By combining the polymerase chain reaction (PCR) of the gamma globin gene promoters with synthetic oligonucleotide analysis we have diagnosed the -196 C----T and the -117 G----A substitutions in heterozygous carriers of non deletional A gamma HPFH from two unrelated Italian families. The identification of the beta-thalassemic defect in a compound heterozygote for -196 A gamma HPFH/beta thalassemia allows us to discuss the effect of this gamma promoter mutation on the globin chain synthetic pattern, and to make a comparison with the mutation at the -117 position.

  6. Analysis of the Sub-Millimeter Rotational Spectrum of Urea

    NASA Astrophysics Data System (ADS)

    Thomas, Jessica R.; Fosnight, Alyssa M.; Medvedev, Ivan R.

    2013-06-01

    Urea, ((NH_{2})_{2}CO), has broad presence in biological species. As a byproduct of human metabolism, this molecule is commonly tested for in blood to diagnose different pathologies. Furthermore, urea is seen in interstellar medium and its detection could yield valuable insight into the mechanisms governing star formation. Despite the prevalence of urea, an absence exists in recorded frequencies of this molecule. The new generation of the sub-millimeter telescopes, such as ALMA, HERSCHEL, and SOFIA, allows detection of interstellar molecular spectra at unprecedented spatial and spectral resolutions. The knowledge of the precise frequencies of spectra transitions present in interstellar molecular clouds would alleviate the problem of spectral congestion and aid in molecular identification. This paper reports the most recent investigation of the submillimeter/terahertz gas phase spectrum of urea. Up until now, only the microwave laboratory spectrum of urea's vibrational ground state has been available. This paper reports the high-resolution spectra of urea in the sub-millimeter range, and extends the spectroscopic assignment of the rotational transitions in the vibrational ground state. Additionally, the assignment of the first vibrational state and tentative assignments of two additional vibrational states have been made.

  7. Spectrum analysis of rectangular pulse in the atmospheric turbulence propagation

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Ni, Xiaolong; Jiang, Huilin; Wang, Junran; Liu, Zhi

    2016-11-01

    Atmospheric turbulence has a great influence on the performance of the atmospheric laser communication system reducing the signal to noise ratio (SNR) and increasing the bit error rate (BER). However, there is rarely study on the effect of atmospheric turbulence on the power spectrum of the rectangular pulse. In this paper, a spectral analyzing method is used to analyze the influence of atmospheric turbulence on the signal. An experiment of laser beam propagation characteristic is carried out on a 6km horizontal atmospheric link, the wavelength is 808 nm. The signal is 100MHz rectangular pulse. The waveform of the rectangular pulse is collected by the oscilloscope, and the power spectral density of the signal is calculated and analyzed by the method of periodogram. Experimental results show that the response and noise characteristics of the laser and photoelectric detector have a great influence on the signal power spectrum distribution which can increase the noise component in the 10^6 Hz frequency range. After the atmospheric turbulence propagation, the signal power decreases in the whole frequency range. However, as the existence of atmospheric turbulence, the signal power increases in the atmospheric turbulence characteristic frequency (tens to hundreds of Hz). The noise power increases in the high frequency range (10^7 10^8 Hz).

  8. [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.

  9. Gamma Ray Observatory (GRO) OBC attitude error analysis

    NASA Technical Reports Server (NTRS)

    Harman, R. R.

    1990-01-01

    This analysis involves an in-depth look into the onboard computer (OBC) attitude determination algorithm. A review of TRW error analysis and necessary ground simulations to understand the onboard attitude determination process are performed. In addition, a plan is generated for the in-flight calibration and validation of OBC computed attitudes. Pre-mission expected accuracies are summarized and sensitivity of onboard algorithms to sensor anomalies and filter tuning parameters are addressed.

  10. Normal mode and experimental analysis of TNT Raman spectrum

    NASA Astrophysics Data System (ADS)

    Liu, Yuemin; Perkins, Richard; Liu, Yucheng; Tzeng, Nianfeng

    2017-04-01

    In this study, a Raman spectrum of TNT was characterized through experiments and simulated using 22 hybrid density functional theory (DFT) methods. Among the different hybrid DFT methods, it was found that the most accurate simulation results of the Raman shift frequency were calculated by the O3LYP method. However, the deviations of the calculated Raman frequencies from the experimental value showed no dependency on the abilities of the DFT methods in recovering the correlation energy. The accuracies of the DFT methods in predicting the Raman bands are probably determined by the numerical grid and convergence criteria for optimizations of each DFT method. It was also decided that the prominent Raman shift 1362 cm-1 is mainly caused by symmetric stretching of the 4-nitro groups. Findings of this study can facilitate futuristic development of more effective surface enhanced Raman spectroscopy/scattering (SERS) substrates for explosive characterization and detection.

  11. Factor analysis of the Autism Spectrum Screening Questionnaire.

    PubMed

    Posserud, Britt; Lundervold, Astri J; Steijnen, Maaike C; Verhoeven, Sophie; Stormark, Kjell Morten; Gillberg, Christopher

    2008-01-01

    The present study investigated the factor structure of parent and teacher Autism Spectrum Screening Questionnaire (ASSQ) in a population of 7-9 years old children. For validation purposes, factors derived were correlated with results on the Strengths and Difficulties Questionnaire (SDQ). A three-factor solution was identified on both parent and teacher ASSQ. Most of the variance was explained by one factor including measures of social function, validated by a high correlation with the SDQ peer problems scale. The second factor included measures of autism-associated problems. The items allocated to the third factor were more specific for a cognitive style typically found in high-functioning individuals with autism/Asperger syndrome. This factor did not correlate highly with any of the SDQ subscales. The results indicated that the screening efficiency of ASSQ could be increased by closer examination of the individual profile of factor scores.

  12. 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.

  13. Photonic crystal biosensor based on angular spectrum analysis.

    PubMed

    Hallynck, Elewout; Bienstman, Peter

    2010-08-16

    The need for cost effective and reliable biosensors in e.g. medical applications is an ever growing and everlasting one. Not only do we strive to increase sensitivity and detection limit of such sensors; ease of fabrication or implementation are equally important. In this work, we propose a novel, photonic crystal based biosensor that is able to operate at a single frequency, contrary to resonance based sensors. In a certain frequency range, guided photonic crystal modes can couple to free space modes resulting in a Lorentzian shape in the angular spectrum. This Lorentzian can shift due to refractive index changes and simulations have shown sensitivities of 65 degrees per refractive index unit and more.

  14. [Theoretical analysis of the single optical path spectrum detection in biological tissue].

    PubMed

    Chen, Yun; Du, Zhen-hui; Chen, Feng; Xu, Ke-xin

    2008-06-01

    The technology of spectrum detection with high sensitivity is of significance in clinic diagnosis and tissue optical parameter measurement. A new method of difference-modulated laser spectrum detection was developed in the present paper. The measuring light and the reference light are separated from the lasing light source in this method. After passing through the tissue, the measuring light interferes with the reference light, and the frequency character of spectrum includes the information of the difference of optical path-length between the measuring light and reference light. By using the phase sensitive detector, the spectrum signal with different frequency can be separated, and consequently the measuring light passed through the tissue with different optical length will be apart. The mechanism of difference-modulated laser spectrum was analyzed and the value of dominant frequency of spectrum was deduced. Based on the theory of the optical path distribution in biological tissue, the spectrum signature of measuring light was discussed also. The distribution of dominant frequency component is decided by the difference of optical path-length between measuring light and reference light when the modulation parameters are invariable, and the magnitude of tissue' s modulus decay will effect the energy distribution of spectrum frequencies component. Theoretical analysis showed that the method of difference modulation can be used to separate lights according to the optical path-length and realize the single optical path measurement in biological tissue.

  15. 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.

  16. 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.

  17. Soft X-ray emission lines in the afterglow spectrum of GRB 011211: A detailed XMM-Newton analysis

    NASA Astrophysics Data System (ADS)

    Reeves, J. N.; Watson, D.; Osborne, J. P.; Pounds, K. A.; O'Brien, P. T.

    2003-05-01

    We report on an XMM-Newton observation of the X-ray afterglow of the Gamma Ray Burst GRB 011211, originally detected by Beppo-SAX on 11th December 2001. The early afterglow spectrum obtained by XMM-Newton, observed 11 hours after the initial burst, appeared to reveal decaying H-like Kalpha emission lines of Mg, Si, S, Ar and Ca, arising in enriched material with an outflow velocity of order 0.1c (Reeves et al. \\cite{Reeves2002}). This was attributed to matter ejected from a massive stellar progenitor occurring shortly before the burst itself. Here, we present a detailed re-analysis of the XMM-Newton EPIC observations of GRB 011211. In particular, we show that the detection of the soft X-ray line emission appears robust, regardless of detector background, calibration, spectral binning, or the spectral model that is assumed. We demonstrate that thermal emission, from an optically thin plasma, is the most plausible model that can account for the soft X-ray emission, which appears to be the case for at least two burst afterglow spectra observed by XMM-Newton. The X-ray spectrum of GRB 011211 appears to evolve with time after the first 10 ks of the XMM-Newton observation as the Si and S emission lines are only detected during the first 10 ks of observation. The observations suggest that thermal emission is present during the early afterglow spectrum, whilst a power-law component dominates the latter stages. Finally we estimate the mass of the ejected material in GRB 011211 to be of the order 4-20 solar masses.

  18. 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.

  19. 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.

  20. 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

  1. Alternate modal combination methods in response spectrum analysis

    SciTech Connect

    Bezler, P.; Curreri, J.R.; Wang, Y.K.; Gupta, A.K. )

    1990-10-01

    In piping analyses using the response spectrum method Square Root of the Sum of the Squares (SRSS) with clustering between closely spaced modes is the combination procedure most commonly used to combine between the modal response components. This procedure is simple to apply and normally yields conservative estimates of the time history results. The purpose of this study is to investigate alternate methods to combine between the modal response components. These methods are mathematically based to properly account for the combination between rigid and flexible modal responses as well as closely spaced modes. The methods are those advanced by Gupta, Hadjian and Lindely-Yow to address rigid response modes and the Double Sum Combination (DSC) method and the Complete Quadratic Combination (CQC) method to account for closely spaced modes. A direct comparison between these methods as well as the SRSS procedure is made by using them to predict the response of six piping systems. The results provided by each method are compared to the corresponding time history estimates of results as well as to each other. The degree of conservatism associated with each method is characterized. 19 refs., 16 figs., 10 tabs.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. Localising Microaneurysms in Fundus Images Through Singular Spectrum Analysis.

    PubMed

    Wang, Su; Tang, Hongying Lilian; Al Turk, Lutfiah Ismail; Hu, Yin; Sanei, Saeid; Saleh, George Michael; Peto, Tunde

    2016-06-27

    Reliable recognition of microaneurysms is an essential task when developing an automated analysis system for diabetic retinopathy detection. In this work, we propose an integrated approach for automated microaneurysm detection with high accuracy.

  8. 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…

  9. 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…

  10. 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.

  11. [Quantitative spectrum analysis of characteristic gases of spontaneous combustion coal].

    PubMed

    Liang, Yun-Tao; Tang, Xiao-Jun; Luo, Hai-Zhu; Sun, Yong

    2011-09-01

    Aimed at the characteristics of spontaneous combustion gas such as a variety of gases, lou limit of detection, and critical requirement of safety, Fourier transform infrared (FTIR) spectral analysis is presented to analyze characteristic gases of spontaneous combustion In this paper, analysis method is introduced at first by combing characteristics of absorption spectra of analyte and analysis requirement. Parameter setting method, sample preparation, feature variable abstract and analysis model building are taken into consideration. The methods of sample preparation, feature abstraction and analysis model are introduced in detail. And then, eleven kinds of gases were tested with Tensor 27 spectrometer. CH4, C2H6, C3H8, iC4H10, nC4H10, C2 H4, C3 H6, C3 H2, SF6, CO and CO2 were included. The optical path length was 10 cm while the spectra resolution was set as 1 cm(-1). The testing results show that the detection limit of all analytes is less than 2 x 10(-6). All the detection limits fit the measurement requirement of spontaneous combustion gas, which means that FTIR may be an ideal instrument and the analysis method used in this paper is competent for spontaneous combustion gas measurement on line.

  12. [Fluorescence spectrum analysis system for protoporphyrin IX in serum based on wavelet transform].

    PubMed

    Zhu, Dian-ming; Yang, Hong-peng; Luo, Xiao-sen; Liu, Ying; Shen, Zhong-hua; Lu, Jian; Ni, Xiao-wu

    2007-12-01

    Protoporphyrin IX is an important kind of organic compound for vital movement, and can be used as the sign of tumour blood. Human protoporphyrin IX content in serum is very low, and affected by various factors. The serum fluorescence spectrum analysis system based on wavelet transform was used to discriminated the protoporphyrin IX weak signals. The protoporphyrin IX fluorescence spectrum was obtained by a multi-function spectrum measuring system, and decomposed several times by wavelet transform to distinguish the noise and spectrum signals. The fluorescence spectrum can be divided into corresponding discrete approximations signals (a1-a6) and discrete details signals (d1-d6) by six times of decomposition, showing the signal frequency decreasing with decomposition times increasing and the protoporphyrin IX fluorescence character peak appears here. The weak signals were discriminated and the exactly component and quantity can be acquired for further analysis. So it can be analysed quantitatively. The researches in the present paper provide the potential application in the diagnosis of incipient tumous using the serum fluorescence spectrum

  13. Shear-layer detection in poststenotic flow by spectrum analysis of Doppler signals.

    PubMed

    Tamura, T; Fronek, A

    1988-11-01

    Spectrum analysis of the Doppler signals was performed 0.5 tube diameters downstream from an axisymmetric constriction with an area reduction of 80 percent in steady flow at a jet Reynolds number of 2840. Both pulsed and continuous wave (CW) Doppler spectra showed significant reverse flow components in the separated flow. The pulsed Doppler spectra exhibited sudden changes when the sample volume crossed the shear layer between the center jet and the separated flow. A power spectrum equation was theoretically derived from continuity of flow to define the Doppler shift frequency for the shear layer velocity. The CW Doppler spectrum showed a minimum spectrum density at a frequency which equalled the shear layer Doppler shift frequency derived from the equation. The pulsed spectra exhibited the sudden changes at the same frequency as well.

  14. Analysis of x-ray spectrum obtained in electron cyclotron resonance x-ray source

    SciTech Connect

    Baskaran, R.; Selvakumaran, T.S.; Sunil Sunny, C.

    2006-03-15

    The analysis of the x-ray spectrum obtained in electron cyclotron resonance (ECR) x-ray source is carried out. Assuming single-particle motion, the electron acceleration and its final energy are calculated for TE{sub 111} cylindrical cavity field and uniform external dc magnetic field. In the calculation, initial coordinates of 40 000 electrons were uniformly selected over the central plane of the cavity using random number generator. The final energy of each electron when it hits the wall is stored and the electron energy distribution is obtained. Using the general purpose Monte Carlo N-particle transport code version 4A, the geometry of the ECR x-ray source is modeled. The x-ray energy spectrum is calculated for the geometry model and the numerically calculated electron energy distribution. The calculated x-ray spectrum is compared with the experimentally measured x-ray spectrum.

  15. EEG power spectrum analysis for monitoring depth of anaesthesia during experimental surgery.

    PubMed

    Otto, Klaus A

    2008-01-01

    The first attempts to introduce computerized power spectrum analysis of the electroencephalogram (EEG) as an intraoperative anaesthesia monitoring device started approximately 30 years ago. Since that time, the effects of various anaesthetic agents, sedative and analgesic drugs on the EEG pattern have been addressed in numerous studies in human patients and different animal species. These studies revealed dose-dependent changes in the EEG power spectrum for many intravenous and volatile anaesthetics. Moreover, EEG responses evoked by surgical stimuli during relative light levels of surgical anaesthesia have been classified as 'arousal' and 'paradoxical arousal' reaction, previously referred to as 'desynchronization' and 'synchronization', respectively. Contrasting reports on the correlation between quantitative EEG (QEEG) variables derived from power spectrum analysis (i.e. spectral edge frequency, median frequency) and simultaneously recorded clinical signs such as movement and haemodynamic responses, however, limited the routine use of intraoperative EEG monitoring. In addition, the appearance of EEG burst suppression pattern and isoelectricity at clinically relevant concentrations/doses of newer general anaesthetics (i.e. isoflurane, sevoflurane, propofol) may have weakened the dose-related EEG changes previously reported. Despite these findings, the EEG power spectrum analysis may still provide valuable information during intraoperative monitoring in the individual subject. The information obtained from EEG power spectrum analysis may be further supplemented by newer EEG indices such as bispectral index and approximate entropy or other neurophysiological monitors including auditory evoked potentials or somatosensory evoked potentials.

  16. 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.

  17. Determination of boron in materials by cold neutron prompt gamma-ray activation analysis.

    PubMed

    Paul, Rick L

    2005-01-01

    An instrument for cold neutron prompt gamma-ray activation analysis (PGAA), located at the NIST Center for Neutron Research (NCNR), has proven useful for the measurement of boron in a variety of materials. Neutrons, moderated by passage through liquid hydrogen at 20 K, pass through a (58)Ni coated guide to the PGAA station in the cold neutron guide hall of the NCNR. The thermal equivalent neutron fluence rate at the sample position is 9 x 10(8) cm(-2) s(-1). Prompt gamma rays are measured by a cadmium- and lead-shielded high-purity germanium detector. The instrument has been used to measure boron mass fractions in minerals, in NIST SRM 2175 (Refractory Alloy MP-35-N) for certification of boron, and most recently in semiconductor-grade silicon. The limit of detection for boron in many materials is <10 ng g(-1).

  18. Load-signature analysis for pack rolling of near-gamma titanium aluminide alloys

    SciTech Connect

    Semiatin, S.L. . Metals and Ceramics Division); Seetharaman, V. )

    1994-11-01

    The objective of the present work was to demonstrate the sensitivity of rolling-load signature analysis as a means to monitor hot-pack-rolling processes for the fabrication of sheet of near-gamma titanium-aluminide alloy sand other difficult-to-work materials. In previous work, a simple method was developed for the prediction of temperature transients during two steps in the pack-rolling process: the transfer of the pack from the furnace to the rolling mill and the actual rolling operation itself. The accuracy of the temperature-transient calculations was established through load-signature data obtained during trials for Ti-48Al (atomic percent) rolled at a single nominal (furnace) temperature. In the present work, additional results are presented and discussed for hot pack rolling at various nominal temperatures and for a range of near-gamma titanium-aluminide alloys.

  19. 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.

  20. 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.

  1. The sensitivity of ArcCHECK-based gamma analysis to manufactured errors in helical tomotherapy radiation delivery.

    PubMed

    Templeton, Alistair K; Chu, James C H; Turian, Julius V

    2015-01-08

    Three-dimensional measurement arrays are an efficient means of acquiring a distribution of data for patient plan delivery QA. However, the tie between plan integrity and traditional gamma-based analysis of these data are not clear. This study explores the sensitivity of such analysis by creating errors in Helical Tomotherapy delivery and measuring the passing rates with an ArcCHECK cylindrical diode array. Errors were introduced in each of the couch speed, leaf open time, and gantry starting position in increasing magnitude while the resulting gamma passing rates were tabulated. The error size required to degrade the gamma passing rate to 90% or below was on average a 3% change in couch speed, 5° in gantry synchronization, or a 5 ms in leaf closing speed for a 3%/3 mm Van Dyk gamma analysis. This varied with plan type, with prostate plans exhibiting less sensitivity than head and neck plans and with gamma analysis criteria, but in all cases the error magnitudes were large compared to actual machine tolerances. These findings suggest that the sensitivity of ArcCHECK-based gamma analysis to single-mode errors in tomotherapy plans is dependent upon plan and analysis type and at traditional passing thresholds unable to detect small defects in the plan.

  2. 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…

  3. 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…

  4. Magnetic Microcalorimeter Gamma Detectors for High-Precision Non-Destructive Analysis

    SciTech Connect

    Friedrich, Stephan; Bates, Cameron; Pereverzev, Sergey

    2014-10-03

    Cryogenic gamma (γ) detectors with operating temperatures of ~0.1 K offer 10× better energy resolution than conventional high-purity germanium detectors that are currently used for non-destructive analysis (NDA) of nuclear materials. This can greatly increase the accuracy of NDA, especially at low-energies where gamma rays often have similar energies and cannot be resolved by Ge detectors. Among the different cryogenic detector types, Magnetic Micro-Calorimeters (MMCs) have the potential of faster count rates and better linearity. High linearity is essential to add spectra from different pixels in detector arrays that are needed for high sensitivity. MMC gamma detectors measure the energy of absorbed gamma rays form the resulting change in magnetization of an erbium-doped gold (Au:Er) sensor. The signal is read out with a SQUID preamplifier and processed digitally with room temperature electronics (see inset figure 2). The objective of this project is to develop ultra-high energy resolution γ-detectors based on magnetic micro-calorimeters (MMCs) for accurate non-destructive isotope analysis (NDA). Since MMCs, like other cryogenic γ-detector technologies with operating temperatures <0.1 K, are intrinsically slow and have to be small for high resolution, special emphasis will be placed on questions that determine sensitivity and the potential for scaling to arrays. Objectives for FY14 were therefore to fabricate an improved version of MMC γ-detectors and test their energy resolution, maximum count rate, readout noise, crosstalk between pixels and linearity.

  5. SU-E-T-359: Emulation of Yb-169 Gamma-Ray Spectrum Using Metal-Filtered 250 KVp X-Rays for Pre-Clinical Studies of Gold Nanoparticle-Aided Radiation Therapy

    SciTech Connect

    Reynoso, F; Cho, S

    2015-06-15

    Purpose: To develop an external beam surrogate of the Yb-169 brachytherapy source applying a filter-based spectrum modulation technique to 250 kVp x-rays. In-vitro/vivo studies performed with the modulated 250 kVp beam will help gauge the benefits of implementing gold nanoparticle-aided radiotherapy with the Yb-169 source. Methods: A previously validated MCNP5 model of the Phillips RT-250 orthovoltage unit was used to obtain the percentage depth dose (PDD) and filtered photon spectra for a variety of filtration and irradiation conditions. Photon spectra were obtained using the average flux F4 tally in air right after all collimation. A 30 x 30 x 30 cm{sup 3} water phantom was used to compute the PDD along the central axis (CAX) under the standards conditions of a 10 x 10 cm{sup 2} field size at 50 cm SSD. Cylindrical cells of 4 cm in diameter and the energy deposition F6 tally were used along the CAX to score the doses down to 20 cm depth. The number of particle history was set to 2 x 10{sup 8} in order to keep the relative uncertainty within each cell < 0.3%. The secondary electron spectrum within a gold-loaded tissue due to each photon spectrum was also calculated using EGSnrc and compared with that due to Yb-169 gamma rays. Results: Under the practical constraints for the spectrum modulation task, 250 kVp x-rays filtered by a 0.25 mm Erbium (Er) foil produced the best match with Yb-169 gamma rays, in terms of PDD and, more importantly, secondary electron spectrum. Conclusion: Modulation of 250kVp x-ray spectrum by an Er-filter was found effective in emulating the gamma ray spectrum of Yb-169. Possible benefits as predicted from the current MC model such as enhanced radiosensitization with the Er-filtered beam (as a surrogate of Yb-169) was confirmed with a separate in-vitro study. Supported by DOD/PCRP grant W81XWH-12-1-0198.

  6. [Research progress in water quality monitoring technology based on ultraviolet spectrum analysis].

    PubMed

    Zeng, Tian-Ling; Wen, Zhi-Yu; Wen, Zhong-Quan; Zhang, Zhong-Wei; Wei, Kang-Lin

    2013-04-01

    The water quality monitoring technology based on ultraviolet spectrum analysis has the characteristics of small volume, low cost, and no secondary pollution, and it doesn't need any reagent and sample pretreatment. On account of these characteristics, the direct ultra-violet technology has remarkable superiority over traditional technologies when applied in online monitoring of drinking water, surface water and industrial wastewater, and it has become an important development tendency of modern water monitoring technologies. The principle, characteristics, present situation and development trend of modern water quality monitoring technology based on ultra-violet spectrum analysis were introduced, and the key technical problems were further discussed in this paper.

  7. 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.

  8. 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.

  9. 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

  10. Power spectrum analysis and cardiovascular morbidity in anxiety disorders.

    PubMed

    Cohen, Hagit; Benjamin, Jonathan

    2006-07-30

    Spectral analysis of heart rate variability (HRV) and related measures has been shown to be a reliable noninvasive technique enabling quantitative assessment of cardiovascular autonomic regulatory responses to autonomic regulatory mechanisms; it provides a dynamic probe of sympathetic and parasympathetic tone, reflecting the interactions between the two. Over 20 studies reported abnormalities of HRV in anxiety, and patients with heart disease and anxiety are at increased risk for morbidity and mortality. Psychiatric drugs partly correct abnormalities of HRV and, recently, autonomic drugs (beta-blockers) have been studied in anxiety disorders. The authors call for further studies, especially in patients with co-existing anxiety disorders and heart disease, incorporating assessment of HRV.

  11. 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.

  12. 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.

  13. A meta-analysis of the social communication questionnaire: Screening for autism spectrum disorder.

    PubMed

    Chesnut, Steven R; Wei, Tianlan; Barnard-Brak, Lucy; Richman, David M

    2016-08-07

    The current meta-analysis examines the previous research on the utility of the Social Communication Questionnaire as a screening instrument for autism spectrum disorder. Previously published reports have highlighted the inconsistencies between Social Communication Questionnaire-screening results and formal autism spectrum disorder diagnoses. The variations in accuracy resulted in some researchers questioning the validity of the Social Communication Questionnaire. This study systematically examined the accuracy of the Social Communication Questionnaire as a function of the methodological decisions made by researchers screening for autism spectrum disorder over the last 15 years. Findings from this study suggest that the Social Communication Questionnaire is an acceptable screening instrument for autism spectrum disorder (area under the curve = 0.885). Variations in methodological decisions, however, greatly influenced the accuracy of the Social Communication Questionnaire in screening for autism spectrum disorder. Of these methodological variations, using the Current instead of the Lifetime version of the Social Communication Questionnaire resulted in the largest detrimental effect (d = -3.898), followed by using the Social Communication Questionnaire with individuals younger than 4 years of age (d = -2.924) and relying upon convenience samples (d = -4.828 for clinical samples, -2.734 for convenience samples, and -1.422 for community samples). Directions for future research and implications for using the Social Communication Questionnaire to screen for autism spectrum disorder are discussed.

  14. [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.

  15. Prompt gamma activation analysis (PGAA) and short-lived neutron activation analysis (NAA) applied to the characterization of legacy materials

    SciTech Connect

    Firestone, Richard B; English, G.A.; Firestone, R.B.; Perry, D.L.; Reijonen, J.P.; Leung, Ka-Ngo; Garabedian, G.F.; Molnar, G.L.; Revay, Zs.

    2008-02-13

    Without quality historical records that provide the composition of legacy materials, the elemental and/or chemical characterization of such materials requires a manual analytical strategy that may expose the analyst to unknown toxicological hazards. In addition, much of the existing legacy inventory also incorporates radioactivity, and, although radiological composition may be determined by various nuclear-analytical methods, most importantly, gamma-spectroscopy, current methods of chemical characterization still require direct sample manipulation, thereby presenting special problems with broad implications for both the analyst and the environment. Alternately, prompt gamma activation analysis (PGAA) provides a'single-shot' in-situ, non-destructive method that provides a complete assay of all major entrained elemental constituents.1-3. Additionally, neutron activation analysis (NAA) using short-lived activation products complements PGAA and is especially useful when NAA activation surpasses the PGAA in elemental sensitivity.

  16. Ultrasound characterization of the infertile male testis with rf power spectrum analysis

    NASA Astrophysics Data System (ADS)

    Coleman, Jonathan A.; Silverman, Ronald H.; Rondeau, Mark; Coleman, D. J.; Schlegel, Peter

    2002-04-01

    Objective: To investigate and diagnose testicular pathology in patients with testicular dysfunction using the technique of ultrasound power spectrum analysis. Methods: Testicular ultrasound studies with power spectrum tissue characterization analysis were performed on men with testicular abnormalities as well as normal controls. Semen analysis, biopsy data, microscopic intra-operative findings and data pertaining to testicular function were collected for each surgically evaluated subject. Ultrasound data were analyzed for power spectrum characteristics of microscopic scatterer size and concentration within discrete areas of testicular tissue. Results: Patients with varicoceles and greater than 2x106 sperm/ml on semen analysis had larger average scatterer size (107.7 micrometers ) and lower scatterer concentration (-15.02 dB) than non-obstructed, azoospermic patients with varicoceles (92.4 micrometers and -11.41 dB, respectively). Subjects with obstructed azoospermia had slightly larger average tissue scatterer size (108.1 micrometers ) and lower concentration (-15.73 dB) while normal control data revealed intermediate values of size (102.3 micrometers ) and concentration (-13.1 dB) of scatterers. Spectral data from pure testicular seminoma lesions had the lowest average scatterer size (82.3 micrometers ) with low relative concentration (-14.7 dB). Summary: Ultrasound tissue characterization based on RF spectrum analysis may distinguish different types of testicular pathology including obstructed and non-obstructed azoospermia and tissue changes due to varicocele and tumor.

  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. Prompt gamma neutron activation analysis of toxic elements in radioactive waste packages.

    PubMed

    Ma, J-L; Carasco, C; Perot, B; Mauerhofer, E; Kettler, J; Havenith, A

    2012-07-01

    The French Alternative Energies and Atomic Energy Commission (CEA) and National Radioactive Waste Management Agency (ANDRA) are conducting an R&D program to improve the characterization of long-lived and medium activity (LL-MA) radioactive waste packages. In particular, the amount of toxic elements present in radioactive waste packages must be assessed before they can be accepted in repository facilities in order to avoid pollution of underground water reserves. To this aim, the Nuclear Measurement Laboratory of CEA-Cadarache has started to study the performances of Prompt Gamma Neutron Activation Analysis (PGNAA) for elements showing large capture cross sections such as mercury, cadmium, boron, and chromium. This paper reports a comparison between Monte Carlo calculations performed with the MCNPX computer code using the ENDF/B-VII.0 library and experimental gamma rays measured in the REGAIN PGNAA cell with small samples of nickel, lead, cadmium, arsenic, antimony, chromium, magnesium, zinc, boron, and lithium to verify the validity of a numerical model and gamma-ray production data. The measurement of a ∼20kg test sample of concrete containing toxic elements has also been performed, in collaboration with Forschungszentrum Jülich, to validate the model in view of future performance studies for dense and large LL-MA waste packages.

  19. 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.

  20. Gap Filling of Precipitation Data by SSA - Singular Spectrum Analysis

    NASA Astrophysics Data System (ADS)

    Filho, A. S. F.; Lima, G. A. R.

    2016-10-01

    From the macroscopic standpoint, the precipitation time series is obtained from observation of natural systems rather than in the laboratory. These time series are often full of gaps (missing values) due to the conditions under which the measurements are made. Missing values give rise to various problems in spectral estimation, inhibit statistical analysis and in specifying boundary conditions for numerical models. Hence, gap filling is necessary in environmental science. The aim of this study is to highlight the application of the SSA forecasting algorithm to fill in missing values to real-life time series. It was applied to several monthly precipitation time series recorded over a large savannah area in Brazil. The results are promising and the accuracy and reliability depend on the pattern and relative length of the gaps with respect to the total length of the time series and presence of noise.

  1. SU-E-T-647: Quality Assurance of VMAT by Gamma Analysis Dependence On Low-Dose Threshold

    SciTech Connect

    Song, J; Kim, M; Lee, S; Lee, M; Suh, T; Park, S

    2015-06-15

    Purpose: The AAPM TG-119 instructed institutions to use low-dose threshold (LDT) of 10% or a ROI determined by the jaw when they collected gamma analysis QA data of planar dose distribution. Also, based on a survey by Nelms and Simon, more than 70% of institutions use a LDT between 0% and 10% for gamma analysis. However, there are no clinical data to quantitatively demonstrate the impact of the LDT on the gamma index. Therefore, we performed a gamma analysis with LDTs of 0% to 15% according to both global and local normalization and different acceptance criteria: 3%/3 mm, 2%/2 mm, and 1%/1 mm. Methods: A total of 30 treatment plans—10 head and neck, 10 brain, and 10 prostate cancer cases—were randomly selected from the Varian Eclipse TPS, retrospectively. For the gamma analysis, a predicted portal image was acquired through a portal dose calculation algorithm in the Eclipse TPS, and a measured portal image was obtained using a Varian Clinac iX and an EPID. Then, the gamma analysis was performed using the Portal Dosimetry software. Results: For the global normalization, the gamma passing rate (%GP) decreased as the LDT increased, and all cases of low-dose thresholds exhibited a %GP above 95% for both the 3%/3 mm and 2%/2 mm criteria. However, for local normalization, the %GP increased as LDT increased. The gamma passing rate with LDT of 10% increased by 6.86%, 9.22% and 6.14% compared with the 0% in the case of the head and neck, brain and prostate for 3%/3 mm criteria, respectively. Conclusion: Applying the LDT in the global normalization does not have critical impact to judge patient-specific QA results. However, LDT for the local normalization should be carefully selected because applying the LDT could affect the average of the %GP to increase rapidly.

  2. [Contribution of 210Bi beta-ray induced bremsstrahlung to the emission of Pb-KX-rays observed in the lead shielded gamma-ray background spectrum (author's transl)].

    PubMed

    Shima, K; Mihara, T; Umetani, K; Mikumo, T

    1980-08-01

    Observation of gamma-ray background has been done by using a Ge(Li) semiconductor detector when it was placed inside the lead shielding material. With the aid of a very simple model calculation, the concentration of 210Pb radioisotope embedded in the lead material has been estimated to be 0.1-0.4 (Bq/Pb-g) (3-12 (pCi/Pb-g). The origin of Pb-KX-ray emission, the highest peak in the background spectrum, has been investigated by comparing the 210Pb-47 keV gamma-ray and Pb-KX-ray peak counts. As the results, about 50 +/- 30% of Pb-KX-ray production is estimated to be due to the Pb-K shell photoionization which is induced by the bremsstrahlung of 210Bi beta-ray.

  3. Fractal analysis of surface electromyography signals: a novel power spectrum-based method.

    PubMed

    Talebinejad, Mehran; Chan, Adrian D C; Miri, Ali; Dansereau, Richard M

    2009-10-01

    This paper presents a novel power spectrum-based method for fractal analysis of surface electromyography signals. This method, named the bi-phase power spectrum method, provides a bi-phase power-law which represents a multi-scale statistically self-affine signal. This form of statistical self-affinity provides an accurate approximation for stochastic signals originating from a strong non-linear combination of a number of similar distributions, such as surface electromyography signals which are formed by the summation of a number of single muscle fiber action potentials. This power-law is characterized by a set of spectral indicators, which are related to distributional and geometrical characteristics of the electromyography signal's interference pattern. These novel spectral indicators are capable of sensing the effects of motor units' recruitment and shape separately by exploiting the geometry of the interference pattern. The bi-phase power spectrum method is compared to geometrical techniques and the 1/f(alpha) approach for fractal analysis of electromyography signals. The extracted indicators using the bi-phase power spectrum method are evaluated in the context of force and joint angle and the results of a human study are presented. Results demonstrate that the bi-phase power spectrum method provides reliable information, consisting of components capable of sensing force and joint angle effects separately, which could be used as complementary information for confounded conventional measures.

  4. [Method of infrared spectrum analysis of hydrocarbon mixed gas based on multilevel and SVM-subset].

    PubMed

    Bai, Peng; Xie, Wen-Jun; Liu, Jun-Hua

    2008-02-01

    The hydrocarbon mixed gas was characterized by multi-component and varied density. In order to deal with the difficulties that can not be actually solved with mass mixture gas spectrum data samples, 15 kinds of subset patterns were determined on the basis of investigations and studies, which needed 5 500 spectrum data samples for training and testing. On the basis of this, a method of hydrocarbon mixed gas infrared spectrum analysis based on 2-levels and 15 SVM-subsets was proposed in the light of the idea of working pattern recognition --> mixture gas analysis --> the final result output. In order to solve the problem of new subset working pattern, the SVM online categorization algorithm based on spectrum data relational rule was used. The experimental results show that the component concentration maximal deviation is 0.41% and the maximal average deviation is 0.04%. The method can be used in other mixture gas infrared spectrum analyses, and has the theoretic and application value.

  5. 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.

  6. "When one photon was a discovery, two was a spectrum, and three was the Rossi prize", documents from the beginnings of gamma ray astronomy.

    NASA Astrophysics Data System (ADS)

    Trimble, V.

    Gamma ray astronomy was nearly 15 years old and had already been honored with a review in ARA&A when SAS-2 saw the first extra-solar-system photon above 100 keV (and also roughly the next 7999). The initial gamma ray sources were considerably fainter than early predictions from nuclear gamma ray lines alone. The field has been dogged throughout its history by a curious mismatch between expectation and reality. An extreme case is gamma ray bursts, of which two kinds were predicted (supernova shock break-outs and evaporating black holes) and two kinds were seen (classic and soft repeaters), but they are not the same two kinds. Examination of contemporary publications provides less insight into the reasons for this than had been expected.

  7. [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.

  8. A Meta-Analysis of Behavioral Interventions for Adolescents and Adults with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Roth, Matthew E.; Gillis, Jennifer M.; DiGennaro Reed, Florence D.

    2014-01-01

    Evaluation of evidence-based treatments is important for adolescents and adults with autism spectrum disorders (ASD) given the increasing number of interventions available and the prevalence of ASD. In this study, we sought to evaluate the effectiveness of behavioral interventions for this population by conducting a meta-analysis of published…

  9. 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…

  10. 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…

  11. 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…

  12. 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…

  13. 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…

  14. 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,…

  15. 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…

  16. 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…

  17. Report on the analysis of common beverages spiked with gamma-hydroxybutyric acid (GHB) and gamma-butyrolactone (GBL) using NMR and the PURGE solvent-suppression technique.

    PubMed

    Lesar, Casey T; Decatur, John; Lukasiewicz, Elaan; Champeil, Elise

    2011-10-10

    In forensic evidence, the identification and quantitation of gamma-hydroxybutyric acid (GHB) in "spiked" beverages is challenging. In this report, we present the analysis of common alcoholic beverages found in clubs and bars spiked with gamma-hydroxybutyric acid (GHB) and gamma-butyrolactone (GBL). Our analysis of the spiked beverages consisted of using (1)H NMR with a water suppression method called Presaturation Utilizing Relaxation Gradients and Echoes (PURGE). The following beverages were analyzed: water, 10% ethanol in water, vodka-cranberry juice, rum and coke, gin and tonic, whisky and diet coke, white wine, red wine, and beer. The PURGE method allowed for the direct identification and quantitation of both compounds in all beverages except red and white wine where small interferences prevented accurate quantitation. The NMR method presented in this paper utilizes PURGE water suppression. Thanks to the use of a capillary internal standard, the method is fast, non-destructive, sensitive and requires no sample preparation which could disrupt the equilibrium between GHB and GBL.

  18. A meta-analysis of treatment of vestibular schwannoma using Gamma Knife radiosurgery

    PubMed Central

    Zabek, Miroslaw

    2014-01-01

    Aim of the study One of the alternative methods of surgical treatment of vestibular schwannoma is Gamma Knife radiosurgery. The purpose of this metaanalysis was to analyze the progress in treatment of vestibular schwannoma using Gamma Knife radiosurgery based on data in the literature of the last five years. Material and methods In the collected English-language literature from the years 2007–2011, contained in 20 scientific journals, clinical articles of many years study at a single center were extracted and also review papers and case reports. The main criteria of our own analysis were: patient age, tumor size, the dose in Gy, the time from surgery to follow-up, the degree of tumor growth inhibition, and hearing preservation. For statistical calculations comparing series of studies we used nonparametric analysis of variance and tests at the significance level of p > 0.05. Results The 46 evaluated clinical articles show the results of studies over many years. A comparison of the results of the analysis made on the basis of papers published in the period 1998-2007 with the results of the current series from the period 2007–2011 allowed us to establish that the average dose applied to the periphery of the tumor was lower (12.4 Gy) than in the earlier series of 1998–2007 (14.2 Gy), and hearing preservation was higher (66.45% vs. 51.0%). Conclusions Clinical findings widely documented in the literature over the past five years indicate the progress in treatment of vestibular schwannoma using Gamma Knife radiosurgery. PMID:24876823

  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. Detection of gamma-irradiated peanuts by ESR spectroscopy and GC analysis of hydrocarbons

    NASA Astrophysics Data System (ADS)

    Ming Li, Wei; Li, An; Ming Ha, Yi; Wang, Feng; Li Zhang, Yan

    2011-03-01

    Peanuts were analyzed by electron spin resonance (ESR) spectroscopy and gas chromatography (GC) before and after gamma irradiation. Using European protocols, the validity and effectiveness of these two techniques were compared with regard to sample preparation, sample and solvent consumption and dose-response curves after irradiation. The results showed the possibility of using ESR and GC for distinguishing between irradiated and unirradiated peanuts. A radiation dose of 0.1 kGy could be detected by ESR but not by GC. The results also indicated that GC is an effective method for qualitative analysis of irradiated peanut, while ESR is suitable for the rapid detection of irradiated peanuts.

  1. Automatic and Interactive Analysis Software for Beta-Gamma Coincidence Systems Used in CTBT Monitoring

    DTIC Science & Technology

    2000-09-01

    publication in the Journal of Radioanalytical and Nuclear Chemistry , April 2000. [2] Biegalski, K.M.F. and Biegalski, S. “Determining Minimum Detectable... Radioanalytical and Nuclear Chemistry , April 2000. [3] Reeder, P.L., Bowyer, T.W., and Perkins, R.W. “Analysis of Beta-Gamma Spectra for the PNNL ARSA and...DTRA01-99-C-0031 ABSTRACT A suite of software has been developed by Veridian Systems as part of the Prototype International Data Center (PIDC) to assist

  2. Low temperature gamma ray irradiation effects on polymer materials (4)-gas analysis of GFRP and CFRP

    NASA Astrophysics Data System (ADS)

    Kudoh, H.; Kasai, N.; Sasuga, T.; Seguchi, T.

    1996-11-01

    Gas analysis was carried out at RT after gamma-irradiation at room temperature and 77K for glass fiber reinforced plastic (GFRP) and carbon fiber reinforced plastic (CFRP) having the same epoxy resin matrix. Gas yield from CFRP was less than that from GFRP at RT, but comparable at 77 K. The yields of CO and CO 2 showed a large dependence on the irradiation temperature, i.e. they were much less at 77 K. Radiation resistance of GFRP and CFRP towards 77 K irrdiation is expected to be higher than that towards RT irradiation.

  3. [Laser Raman and infrared spectrum analysis of low-density lipoproteins purified from hen egg yolk].

    PubMed

    Xue, Hui-jun; Sun, Run-guang; Wang, Xiao-mei; Chang, Yi-guang

    2010-11-01

    During the experiment, diversified proteins were separated from hen egg yolk by ammonium sulphate rapid fractionation, and pure LDL was obtained after filtrating through Sephadex G-200 chromatography. After the qualitative detection of SDS-PAGE, the authors discovered that LDL consists of five major apoprotein. The Raman and infrared spectrum showed CH2 asymmetric stretching and symmetric stretching mode. However, the authors found C==O stretching vibrations of protein peptide bonds and N+ (CH3)3 asymmetric stretching vibration from the choline group in phospholipids. Laser Raman and infrared spectrum analysis of LDL provided useful information for studying their structure.

  4. Status of gamma laser problem on current moment 2000: ranging analysis and screening of gamma laser schemes on their feasibility

    NASA Astrophysics Data System (ADS)

    Karyagin, Stanislav V.

    2001-03-01

    Joint theory of gamma-generation (GG) and radiation-heat regime (GG&RH) in active medium (AM) of (gamma) -laser (GL) is applied for the analyses of total world experience in the GL-problem in order to choose those nuclei-candidates, active media, GL-schemes which are indeed actual for the GL- creation. The classification of GL over a degree of the `comfortable conditions' for the GG is given. The GL-schemes could be `residential (Rsd)' (creation of excited laser- active nuclei, ELAN, from its parents directly in the site of AM) or `nonresidential (Nrsd)' (creation of ELAN out off the AM). It has been turned out that all `residential' part of the world experience does not fit for the realization of GL and can be considered only as a museum-piece. Any Rsd AM on the short-lived isomers must be inevitably blasted before the beginning of the GG. That `museum' part includes a lot of ideas: GG on long-lived isomers; line narrowing by radio- frequency or optical fields; creation of (gamma) -gain in the inversion less mixture of the excited and de-excited nuclei (amplification without inversion); super-dilution of work- nuclei in a matrix via multi wave Borrman effect; non- Moessbauer active media in plasma, gas or beam with its optical laser cooling, a lot of schemes (one-stage, two- stage, two-phase, two-step, two-photon, etc.). The exception could be only Rsd GL pumped by another GL. But the Nrsd part of world experience had stood yet all strict tests of that joint theory.

  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. Neutron activation analysis via nuclear decay kinetics using gamma-ray spectroscopy at SFU

    NASA Astrophysics Data System (ADS)

    Domingo, Thomas; Chester, Aaron; Starosta, Krzysztof; Williams, Jonathan

    2016-09-01

    Gamma-ray spectroscopy is a powerful tool used in a variety of fields including nuclear and analytical chemistry, environmental science, and health risk management. At SFU, the Germanium detector for Elemental Analysis and Radiation Studies (GEARS), a low-background shielded high-purity germanium gamma-ray detector, has been used recently in all of the above fields. The current project aims to expand upon the number of applications for which GEARS can be used while enhancing its current functionality. A recent addition to the SFU Nuclear Science laboratory is the Thermo Scientific P 385 neutron generator. This device provides a nominal yield of 3 ×108 neutrons/s providing the capacity for neutron activation analysis, opening a major avenue of research at SFU which was previously unavailable. The isotopes created via neutron activation have a wide range of half-lives. To measure and study isotopes with half-lives above a second, a new analogue data acquisition system has been installed on GEARS allowing accurate measurements of decay kinetics. This new functionality enables identification and quantification of the products of neutron activation. Results from the neutron activation analysis of pure metals will be presented.

  7. 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.

  8. [New method of mixed gas infrared spectrum analysis based on SVM].

    PubMed

    Bai, Peng; Xie, Wen-Jun; Liu, Jun-Hua

    2007-07-01

    A new method of infrared spectrum analysis based on support vector machine (SVM) for mixture gas was proposed. The kernel function in SVM was used to map the seriously overlapping absorption spectrum into high-dimensional space, and after transformation, the high-dimensional data could be processed in the original space, so the regression calibration model was established, then the regression calibration model with was applied to analyze the concentration of component gas. Meanwhile it was proved that the regression calibration model with SVM also could be used for component recognition of mixture gas. The method was applied to the analysis of different data samples. Some factors such as scan interval, range of the wavelength, kernel function and penalty coefficient C that affect the model were discussed. Experimental results show that the component concentration maximal Mean AE is 0.132%, and the component recognition accuracy is higher than 94%. The problems of overlapping absorption spectrum, using the same method for qualitative and quantitative analysis, and limit number of training sample, were solved. The method could be used in other mixture gas infrared spectrum analyses, promising theoretic and application values.

  9. Adolescent boys with an autism spectrum disorder and their experience of sexuality: An interpretative phenomenological analysis.

    PubMed

    Dewinter, Jeroen; Van Parys, Hanna; Vermeiren, Robert; van Nieuwenhuizen, Chijs

    2017-01-01

    This qualitative study explored how adolescent boys with autism spectrum disorder experience their sexuality. Previous research has demonstrated that sexuality is a developmental task for boys with autism spectrum disorder, as it is for their peers. Case studies have suggested a relation between autism spectrum disorder and atypical sexual development; empirical studies on this subject, however, are scant and inconsistent. This study is based on interviews with eight boys, aged 16-20 years, with Asperger's disorder or autistic disorder. Interpretative phenomenological analysis of the data revealed three major themes relating to (a) how they experience sexual feelings, think about sexuality and think about themselves as sexual beings; (b) how they perceive messages relating to sexuality in their surroundings; and (c) how they experience finding and having a partner and partnered sex. We believe that attention to these themes is needed in assessment, education and further research.

  10. [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.

  11. 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.

  12. Molecular analysis of point mutations in a barley genome exposed to MNU and gamma rays.

    PubMed

    Kurowska, Marzena; Labocha-Pawłowska, Anna; Gnizda, Dominika; Maluszynski, Miroslaw; Szarejko, Iwona

    2012-01-01

    We present studies aimed at determining the types and frequencies of mutations induced in the barley genome after treatment with chemical (N-methyl-N-nitrosourea, MNU) and physical (gamma rays) mutagens. We created M(2) populations of a doubled haploid line and used them for the analysis of mutations in targeted DNA sequences and over an entire barley genome using TILLING (Targeting Induced Local Lesions in Genomes) and AFLP (Amplified Fragment Length Polymorphism) technique, respectively. Based on the TILLING analysis of the total DNA sequence of 4,537,117bp in the MNU population, the average mutation density was estimated as 1/504kb. Only one nucleotide change was found after an analysis of 3,207,444bp derived from the highest dose of gamma rays applied. MNU was clearly a more efficient mutagen than gamma rays in inducing point mutations in barley. The majority (63.6%) of the MNU-induced nucleotide changes were transitions, with a similar number of G>A and C>T substitutions. The similar share of G>A and C>T transitions indicates a lack of bias in the repair of O(6)-methylguanine lesions between DNA strands. There was, however, a strong specificity of the nucleotide surrounding the O(6)-meG at the -1 position. Purines formed 81% of nucleotides observed at the -1 site. Scanning the barley genome with AFLP markers revealed ca. a three times higher level of AFLP polymorphism in MNU-treated as compared to the gamma-irradiated population. In order to check whether AFLP markers can really scan the whole barley genome for mutagen-induced polymorphism, 114 different AFLP products, were cloned and sequenced. 94% of bands were heterogenic, with some bands containing up to 8 different amplicons. The polymorphic AFLP products were characterised in terms of their similarity to the records deposited in a GenBank database. The types of sequences present in the polymorphic bands reflected the organisation of the barley genome.

  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. In vivo elemental analysis by counting neutron-induced gamma rays for medical and biological applications

    NASA Astrophysics Data System (ADS)

    Kehayias, Joseph J.; Ma, Ruimei; Zhuang, Hong; Moore, Robert; Dowling, Lisa

    1995-03-01

    Non-invasive in vivo elemental analysis is a technique used to assess human body composition which is indicative of nutritional status and health condition. The in vivo measurement of the body's major elements is used for a variety of medical studies requiring the determination of the body's compartments (protein, fat, water, bone). Whole body gamma-ray counters, consisting of Nal(Tl) crystal detectors in a shielded room, are used for measuring in vivo the body's Ca, Cl, Na and P by delayed neutron activation analysis. Thermal neutrons from a moderated 238Pu-Be source are used for the measurement of total body nitrogen (and thus protein) and chlorine at low radiation exposure (0.80 mSv). The resulting high energy prompt gamma-rays from nitrogen (10.83 MeV) and chlorine (6.11 MeV) are detected simultaneously with the irradiation. Body fat (the main energy store) and fat distribution (which relates to risk for cardiovascular disease) are measured by detecting C and O in vivo through fast neutron inelastic scattering. A small sealed D-T neutron generator is used for the pulsed (4 - 8 KHz) production of fast neutrons. Carbon and oxygen are detected by counting the 4.44 and 6.13 MeV gamma-rays resulting from the inelastic scattering of the fast neutrons from the 12C and 16O nuclei, respectively. One use of this method is the systematic study of the mechanisms driving the age-associated depletion of the metabolizing, oxygen-consuming cellular compartment of the body. The understanding of this catabolism may suggest ways to maintain lean tissue and thus to preserve quality of life for the very old.

  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. A portable medium-resolution gamma-ray spectrometer and analysis software

    SciTech Connect

    Lavietes, A.D.; McQuaid, J.H.; Ruhter, W.D.; Buckley, W.M.; Clark, D-L.; Paulus, T.J.

    1996-07-01

    There is a strong need for portable radiometric instrumentation that can both accurately confirm the presence of nuclear materials and allow isotopic analysis of radionuclides in the field. To fulfill this need the Safeguards Technology Program at LLNL has developed a hand-held, non-cryogenic, low-power gamma-ray and x-ray measurements and analysis instrument that can both search for and then accurately verify the presence of nuclear materials. We will report on the use of cadmium zinc telluride (CZT) detectors, detector electronics, and the new field-portable instrument being developed. We will also describe the isotopic analysis that allows enrichment measurements to be made accurately in the field. These systems provide capability for safeguards inspection and verification applications and could find application in counter-smuggling operations.

  17. 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.

  18. Analysis of 10B by PIGE with factor analytical gamma-ray peak identification.

    PubMed

    Savolainen, S; Räisänen, J; Eteläniemi, V; Abo Ramadan, U A; Kallio, M

    1995-09-01

    Studying the biodistribution of boronated compounds for B neutron capture therapy (BNCT) requires the accurate detection of low levels of boron (10B) in biological samples. Proton induced gamma-ray emission analysis (PIGE) of 10B was found to be viable in a study of low density lipoprotein (LDL), in tissue and blood samples. However, the method is sensitive to Na present in the samples and can therefore not be used for accurate measurements of 10B concentrations below 5 ppm in samples containing Na. PIGE can be considered to be an appropriate reference method for chemical B analysis. The factor analytical method presented here is the most objective way to separate Na and B peaks from each other, and the factorizing method can be applied in different forms of spectral analysis.

  19. Scission gamma rays

    SciTech Connect

    Danilyan, G. V.; Klenke, J.; Krakhotin, V. A.; Kuznetsov, V. L.; Novitsky, V. V.; Pavlov, V. S.; Shatalov, P. B.

    2009-11-15

    Gamma rays probably emitted by the fissioning nucleus {sup 236}U* at the instant of the break of the neck or within the time of about 10{sup -21} s after or before this were discovered in the experiment devoted to searches for the effect of rotation of the fissioning nucleus in the process {sup 235}U(n,{gamma}f) and performed in a polarized beam of cold neutrons from the MEPHISTO Guideline at the FRM II Munich reactor. Detailed investigations revealed that the angular distribution of these gamma rays is compatible with the assumption of the dipole character of the radiation and that their energy spectrum differs substantially from the spectrum of prompt fission gamma rays. In the measured interval 250-600 keV, this spectrum can be described by an exponential function at the exponent value of {alpha} = -5 x 10{sup -3} keV{sup -1}. The mechanism of radiation of such gamma rays is not known at the present time. Theoretical models based on the phenomenon of the electric giant dipole resonance in a strongly deformed fissioning nucleus or in a fission fragment predict harder radiation whose spectrum differs substantially from the spectrum measured in the present study.

  20. A Statistical Analysis of the Output Signals of an Acousto-Optic Spectrum Analyzer for CW (Continuous-Wave) Signals

    DTIC Science & Technology

    1988-10-01

    A statistical analysis on the output signals of an acousto - optic spectrum analyzer (AOSA) is performed for the case when the input signal is a...processing, Electronic warfare, Radar countermeasures, Acousto - optic , Spectrum analyzer, Statistical analysis, Detection, Estimation, Canada, Modelling.

  1. 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

  2. SU-E-T-679: Retrospective Analysis of the Sensitivity of Planar Dose Measurements To Gamma Analysis Criteria

    SciTech Connect

    Elguindi, S; Ezzell, G; Gagneur, J

    2015-06-15

    Purpose: IMRT QA using planar dose measurements is still a widely used method for checking the accuracy of treatment plans. A pass/fail judgment is made using gamma analysis based on a single endpoint. Using more stringent criteria is a way to increase the sensitivity to planning and delivery errors. Before such implementation, it is necessary to understand how the sensitivity to different gamma criteria settings affects gamma passing rates (GPR). Methods: 752 IMRT QA measurements were re-analyzed with varying distance to agreement (DTA) and dose difference (DD) percentages using a Matlab program. Other quantifying information such as the mean dose difference in the treatment target (defined as points that are greater than 80% of maximal dose) were stored in a relational database for retrospective analysis. Results: The average and standard deviation of GPR (%) fell from 99.84 ± (0.43) to 89.61 ± (6.08) when restricting DD from 5 − 1% respectively, as compared to a drop from 99.15 ± (1.19) to 95.00 ± (4.43), when restricting the DTA from 5 − 1 mm respectively. The mean dose difference (%) in the treatment target between measured and calculated dose was −1.96 ± (0. 83), −0.09 ± (0.98), and 1.44 ± (0. 86) for each of our institution’s three matched linear accelerators (LINAC 1, 2, and 3 respectively). For plans that are approximately 2.7 sigma below the mean GPR, an average of 78.4% of those plans were measured on LINAC 1 or 3, while only 48% of the total plans were run on those machines. Conclusion: The data demonstrates that when restricting gamma criterion, such as the DD, the greatest indicator of reduced GPR in our institution is which matched LINAC the plan was measured on. While small, these differences manifest themselves to levels comparable to other treatment related differences and possibly confound the gamma analysis.

  3. 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.

  4. Association between bipolar spectrum disorder and bone health: a meta-analysis and systematic review protocol

    PubMed Central

    Brennan-Olsen, Sharon L; Stuart, Amanda L; Pasco, Julie A; Berk, Michael; Hodge, Jason M; Williams, Lana J

    2017-01-01

    Introduction Bipolar spectrum disorder is a chronic, episodic illness, associated with significant personal, social and economic burden. It is estimated to affect ∼2.4% of the population worldwide and is commonly associated with psychological and/or physiological comorbidities. Osteoporosis is one such comorbidity, a disease of bone that is asymptomatic until a fracture occurs. This systematic review attempts to capture, collate, assess and discuss the literature investigating the association between bipolar spectrum disorder and bone health. Methods and analysis We aim to identify articles that investigate the association between bipolar spectrum disorder and bone health in adults by systematically searching the MEDLINE, PubMed, OVID and CINAHL databases. Two independent reviewers will determine eligibility of studies according to predetermined criteria, and methodological quality will be assessed using a previously published scoring system. A meta-analysis will be conducted, and statistical methods will be used to identify and control for heterogeneity, if possible. If numerical syntheses are prevented due to statistical heterogeneity, a best evidence synthesis will be conducted to assess the level of evidence for associations between bipolar spectrum disorder and bone health. Ethics and dissemination Ethical permission will not be required for this systematic review since only published data will be used. This protocol will be registered with PROSPERO. Findings of the review will be published in a peer-reviewed scientific journal, and will be presented to clinical and population health audiences at national and international conferences. PMID:28246138

  5. Antiproton constraints on the GeV gamma-ray excess: a comprehensive analysis

    SciTech Connect

    Cirelli, Marco; Giesen, Gaëlle; Taoso, Marco; Gaggero, Daniele; Urbano, Alfredo E-mail: daniele.gaggero@sissa.it E-mail: marco.taoso@cea.fr

    2014-12-01

    A GeV gamma-ray excess has possibly been individuated in Fermi-LAT data from the Galactic Center and interpreted in terms of Dark Matter (DM) annihilations, either in hadronic (essentially b b-bar ) or leptonic channels. In order to test this tantalizing interpretation, we address two issues: (i) we improve the computation of secondary emission from DM (Inverse Compton and Bremsstrahlung) with respect to previous works, confirming it to be very relevant for determining the DM spectrum in the leptonic channels, so that any conclusion on the DM nature of the signal critically depends on this contribution; (ii) we consider the constraints from antiprotons on the DM hadronic channel, finding that the uncertainties on the propagation model, and in particular on the halo height, play a major role. Moreover, we discuss the role of solar modulation, taking into account possible charge dependent effects whose importance is estimated exploiting detailed numerical tools. The limits that we obtain severely constrain the DM interpretation of the excess in the hadronic channel, for standard assumptions on the Galactic propagation parameters and solar modulation. However, they considerably relax if more conservative choices are adopted.

  6. Gamma-ray blazar spectra with H.E.S.S. II mono analysis: The case of PKS 2155-304 and PG 1553+113

    NASA Astrophysics Data System (ADS)

    H.E.S.S. Collaboration; Abdalla, H.; Abramowski, A.; Aharonian, F.; Ait Benkhali, F.; Akhperjanian, A. G.; Andersson, T.; Angüner, E. O.; Arrieta, M.; Aubert, P.; Backes, M.; Balzer, A.; Barnard, M.; Becherini, Y.; Becker Tjus, J.; Berge, D.; Bernhard, S.; Bernlöhr, K.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Brun, F.; Brun, P.; Bryan, M.; Bulik, T.; Capasso, M.; Carr, J.; Casanova, S.; Cerruti, M.; Chakraborty, N.; Chalme-Calvet, R.; Chaves, R. C. G.; Chen, A.; Chevalier, J.; Chrétien, M.; Colafrancesco, S.; Cologna, G.; Condon, B.; Conrad, J.; Couturier, C.; Cui, Y.; Davids, I. D.; Degrange, B.; Deil, C.; Devin, J.; deWilt, P.; Dirson, L.; Djannati-Ataï, A.; Domainko, W.; Donath, A.; Drury, L. O.'C.; Dubus, G.; Dutson, K.; Dyks, J.; Edwards, T.; Egberts, K.; Eger, P.; Ernenwein, J.-P.; Eschbach, S.; Farnier, C.; Fegan, S.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Funk, S.; Füßling, M.; Gabici, S.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J. F.; Gottschall, D.; Goyal, A.; Grondin, M.-H.; Hadasch, D.; Hahn, J.; Haupt, M.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hillert, A.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holler, M.; Horns, D.; Ivascenko, A.; Jacholkowska, A.; Jamrozy, M.; Janiak, M.; Jankowsky, D.; Jankowsky, F.; Jingo, M.; Jogler, T.; Jouvin, L.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kerszberg, D.; Khélifi, B.; Kieffer, M.; King, J.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Krakau, S.; Kraus, M.; Krayzel, F.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lees, J.-P.; Lefaucheur, J.; Lefranc, V.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leser, E.; Lohse, T.; Lorentz, M.; Liu, R.; López-Coto, R.; Lypova, I.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Mohrmann, L.; Morå, K.; Moulin, E.; Murach, T.; de Naurois, M.; Niederwanger, F.; Niemiec, J.; Oakes, L.; O'Brien, P.; Odaka, H.; Öttl, S.; Ohm, S.; Ostrowski, M.; Oya, I.; Padovani, M.; Panter, M.; Parsons, R. D.; Paz Arribas, M.; Pekeur, N. W.; Pelletier, G.; Perennes, C.; Petrucci, P.-O.; Peyaud, B.; Pita, S.; Poon, H.; Prokhorov, D.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Romoli, C.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Salek, D.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwemmer, S.; Settimo, M.; Seyffert, A. S.; Shafi, N.; Shilon, I.; Simoni, R.; Sol, H.; Spanier, F.; Spengler, G.; Spies, F.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tibaldo, L.; Tiziani, D.; Tluczykont, M.; Trichard, C.; Tuffs, R.; Uchiyama, Y.; van der Walt, D. J.; van Eldik, C.; van Soelen, B.; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Vuillaume, T.; Wadiasingh, Z.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zabalza, V.; Zaborov, D.; Zacharias, M.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Ziegler, A.; Żywucka, N.; LAT Collaboration; Ackermann, M.; Ajello, M.; Baldini, L.; Barbiellini, G.; Bellazzini, R.; Blandford, R. D.; Bonino, R.; Bregeon, J.; Bruel, P.; Buehler, R.; Caliandro, G. A.; Cameron, R. A.; Caragiulo, M.; Caraveo, P. A.; Cavazzuti, E.; Cecchi, C.; Chiang, J.; Chiaro, G.; Ciprini, S.; Cohen-Tanugi, J.; Costanza, F.; Cutini, S.; D'Ammando, F.; de Palma, F.; Desiante, R.; Di Lalla, N.; Di Mauro, M.; Di Venere, L.; Donaggio, B.; Favuzzi, C.; Focke, W. B.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giglietto, N.; Giordano, F.; Giroletti, M.; Guillemot, L.; Guiriec, S.; Horan, D.; Jóhannesson, G.; Kamae, T.; Kensei, S.; Kocevski, D.; Larsson, S.; Li, J.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Maldera, S.; Manfreda, A.; Mazziotta, M. N.; Michelson, P. F.; Mizuno, T.; Monzani, M. E.; Morselli, A.; Negro, M.; Nuss, E.; Orienti, M.; Orlando, E.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T. A.; Principe, G.; Rainò, S.; Razzano, M.; Simone, D.; Siskind, E. J.; Spada, F.; Spinelli, P.; Thayer, J. B.; Torres, D. F.; Torresi, E.; Troja, E.; Vianello, G.; Wood, K. S.

    2017-04-01

    Context. The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivityto lower energies. The lowest energy threshold is obtained using monoscopic analysis of data taken with CT5, providing access to gamma-ray energies below 100 GeV for small zenith angle observations. Such an extension of the instrument's energy range is particularly beneficial for studies of active galactic nuclei with soft spectra, as expected for those at a redshift ≥0.5. The high-frequency peaked BL Lac objects PKS 2155-304 (z = 0.116) and PG 1553+113 (0.43 < z < 0.58) are among the brightest objects in the gamma-ray sky, both showing clear signatures of gamma-ray absorption at E > 100 GeV interpreted as being due to interactions with the extragalactic background light (EBL). Aims: The aims of this work are twofold: to demonstrate the monoscopic analysis of CT5 data with a low energy threshold, and to obtain accurate measurements of the spectral energy distributions (SED) of PKS 2155-304 and PG 1553+113 near their SED peaks at energies ≈100 GeV. Methods: Multiple observational campaigns of PKS 2155-304 and PG 1553+113 were conducted during 2013 and 2014 using the full H.E.S.S. II instrument (CT1-5). A monoscopic analysis of the data taken with the new CT5 telescope was developed along with an investigation into the systematic uncertainties on the spectral parameters which are derived from this analysis. Results: Using the data from CT5, the energy spectra of PKS 2155-304 and PG 1553+113 were reconstructed down to conservative threshold energies of 80 GeV for PKS 2155-304, which transits near zenith, and 110 GeV for the more northern PG 1553+113. The measured spectra, well fitted in both cases by a log-parabola spectral model (with a 5.0σ statistical preference for non-zero curvature for PKS 2155-304 and 4.5σ for PG 1553+113), were found consistent with spectra derived from contemporaneous Fermi-LAT data, indicating a sharp break in the

  7. 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).

  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. 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

  10. Development of a Tool for the Rapid Quantitative Analysis of Multiple Gamma Spectra

    SciTech Connect

    HODGE, CHRISTOPHERA.

    2004-06-28

    Often multiple gamma spectra are acquired for the quantitative measurement of process holdup, filter banks, waste containers, D and D objects, or other such items. These spectra can represent data for single items, background data, and multiple assays of the same item or multiple areas representative of a single process area. The spectra are often collected under differing circumstances with regard to attenuating materials, distances, assay times, relative backgrounds, and many other such parameters. Quantitative results, and associated errors, are often dependent on multiple calibration constants, assays of varying isotopes, source geometries (point, line, or area), background averaging, Compton effects, and the accurate analysis, i.e. region of interest, of the raw gamma spectra. A tool has been developed to assist in this endeavor. The calculations have been quality checked so that the tool can readily be used with assurance that the calculations are consistent and correct. This tool allows for multiple spectra (up to 150) to be compared and manipulated. The tool has features for: dynamic average background subtraction; accounting for varying Compton effects; different calibration constants; up to three attenuating materials; any gamma energy; and variance in collection parameters such as distance, angle, assay times, and isotope. Selections of point, line, or area calculations are easily specified. The tool has a report writer that allows for averaging over multiple assays, graphing of activity (e.g., graphing activity in a sump allows the hot spots to be identified), and presentation of results with associated error components or MLDs. The resulting database allows for easy self-documentation and archiving.

  11. WE-G-BRA-08: Failure Modes and Effects Analysis (FMEA) for Gamma Knife Radiosurgery

    SciTech Connect

    Xu, Y; Bhatnagar, J; Bednarz, G; Flickinger, J; Arai, Y; Huq, M Saiful; Vacsulka, J; Monaco, E; Niranjan, A; Lunsford, L Dade; Feng, W

    2015-06-15

    Purpose: To perform a failure modes and effects analysis (FMEA) study for Gamma Knife (GK) radiosurgery processes at our institution based on our experience with the treatment of more than 13,000 patients. Methods: A team consisting of medical physicists, nurses, radiation oncologists, neurosurgeons at the University of Pittsburgh Medical Center and an external physicist expert was formed for the FMEA study. A process tree and a failure mode table were created for the GK procedures using the Leksell GK Perfexion and 4C units. Three scores for the probability of occurrence (O), the severity (S), and the probability of no detection (D) for failure modes were assigned to each failure mode by each professional on a scale from 1 to 10. The risk priority number (RPN) for each failure mode was then calculated (RPN = OxSxD) as the average scores from all data sets collected. Results: The established process tree for GK radiosurgery consists of 10 sub-processes and 53 steps, including a sub-process for frame placement and 11 steps that are directly related to the frame-based nature of the GK radiosurgery. Out of the 86 failure modes identified, 40 failure modes are GK specific, caused by the potential for inappropriate use of the radiosurgery head frame, the imaging fiducial boxes, the GK helmets and plugs, and the GammaPlan treatment planning system. The other 46 failure modes are associated with the registration, imaging, image transfer, contouring processes that are common for all radiation therapy techniques. The failure modes with the highest hazard scores are related to imperfect frame adaptor attachment, bad fiducial box assembly, overlooked target areas, inaccurate previous treatment information and excessive patient movement during MRI scan. Conclusion: The implementation of the FMEA approach for Gamma Knife radiosurgery enabled deeper understanding of the overall process among all professionals involved in the care of the patient and helped identify potential

  12. 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.

  13. Systems analysis evaluation of gamma-ray detectors for remote monitoring applications

    SciTech Connect

    Antolak, A.J.; Lund, J.C.; Lamonds, H.A.; James, R.B.; Hinton, J.; Thomas, G.

    1996-12-31

    Because of the large number of different gamma-ray detectors available, including both scintillation and semiconductor types, extensive analysis may be required to determine which detector system is optimal for a given application. In the selection of detectors for remote monitoring of nuclear materials, a methodology has been developed to assess which detectors are best suited for this application. The analysis provides a numerical ranking of the performance of each detector thereby reducing the large set of all potential detectors to a small tractable set of most promising candidates. The basis for the evaluation will be discussed, along with the application of the methodology to a wide range of scintillator and semiconductor detector materials. The most promising scintillator and semiconductor materials are identified for remote monitoring applications.

  14. Electrospray ionization time-of-flight mass spectrum analysis method of polyaluminum chloride flocculants.

    PubMed

    Feng, Chenghong; Bi, Zhe; Tang, Hongxiao

    2015-01-06

    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.

  15. [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.

  16. Ultrasonic tissue characterization via 2-D spectrum analysis: theory and in vitro measurements.

    PubMed

    Liu, Tian; Lizzi, Frederic L; Ketterling, Jeffrey A; Silverman, Ronald H; Kutcher, Gerald J

    2007-03-01

    A theoretical model is described for application in ultrasonic tissue characterization using a calibrated 2-D spectrum analysis method. This model relates 2-D spectra computed from ultrasonic backscatter signals to intrinsic physical properties of tissue microstructures, e.g., size, shape, and acoustic impedance. The model is applicable to most clinical diagnostic ultrasound systems. Two experiments employing two types of tissue architectures, spherical and cylindrical scatterers, are conducted using ultrasound with center frequencies of 10 and 40 MHz, respectively. Measurements of a tissue-mimicking phantom with an internal suspension of microscopic glass beads are used to validate the theoretical model. Results from in vitro muscle fibers are presented to further elucidate the utility of 2-D spectrum analysis in ultrasonic tissue characterization.

  17. Gamma-Ray Telescopes

    NASA Astrophysics Data System (ADS)

    Weekes, T.; Murdin, P.

    2000-11-01

    Gamma-rays are the highest-energy photons in the ELECTROMAGNETIC SPECTRUM and their detection presents unique challenges. On one hand it is easy to detect γ-rays. The interaction cross-sections are large and above a few MeV the pair production interaction, the dominant γ-ray interaction with matter, is easily recognized. Gamma-ray detectors were far advanced when the concept of `γ-ray astronomy' ...

  18. Functional analysis of gamma-carotene ketolase involved in the carotenoid biosynthesis of Deinococcus radiodurans.

    PubMed

    Sun, Zongtao; Shen, Shaochuan; Tian, Bing; Wang, Hu; Xu, Zhenjian; Wang, Liangyan; Hua, Yuejin

    2009-11-01

    Deinococcus radiodurans strain R1 synthesizes a unique ketocarotenoid product named deinoxanthin. The detailed steps involved in the biosynthesis of deinoxanthin remain unresolved. A carotene ketolase homologue encoded by dr0093 was inactivated by gene mutation to verify its function in the native host D. radiodurans. Analysis of the carotenoids in the resultant mutant R1DeltacrtO demonstrated that dr0093 encodes gamma-carotene ketolase (CrtO) catalysing the introduction of one keto group into the C-4 position of gamma-carotene derivatives to form ketolated carotenoids. The mutant R1DeltacrtO became more sensitive to H(2)O(2) treatment than the wild-type strain R1, indicating that the C-4 keto group is important for the antioxidant activity of carotenoids in D. radiodurans. Carotenoid extracts from mutant R1DeltacrtO exhibited lower 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity than those from the wild-type strain R1. The enhanced antioxidant ability of ketocarotenoids in D. radiodurans might be attributed to its extended conjugated double bonds and relative stability by the C-4 keto group substitution.

  19. Analysis of nonlocal neural fields for both general and gamma-distributed connectivities

    NASA Astrophysics Data System (ADS)

    Hutt, Axel; Atay, Fatihcan M.

    2005-04-01

    This work studies the stability of equilibria in spatially extended neuronal ensembles. We first derive the model equation from statistical properties of the neuron population. The obtained integro-differential equation includes synaptic and space-dependent transmission delay for both general and gamma-distributed synaptic connectivities. The latter connectivity type reveals infinite, finite, and vanishing self-connectivities. The work derives conditions for stationary and nonstationary instabilities for both kernel types. In addition, a nonlinear analysis for general kernels yields the order parameter equation of the Turing instability. To compare the results to findings for partial differential equations (PDEs), two typical PDE-types are derived from the examined model equation, namely the general reaction-diffusion equation and the Swift-Hohenberg equation. Hence, the discussed integro-differential equation generalizes these PDEs. In the case of the gamma-distributed kernels, the stability conditions are formulated in terms of the mean excitatory and inhibitory interaction ranges. As a novel finding, we obtain Turing instabilities in fields with local inhibition-lateral excitation, while wave instabilities occur in fields with local excitation and lateral inhibition. Numerical simulations support the analytical results.

  20. 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.

  1. Spatial analysis of ambient gamma dose equivalent rate data by means of digital image processing techniques.

    PubMed

    Szabó, Katalin Zsuzsanna; Jordan, Gyozo; Petrik, Attila; Horváth, Ákos; Szabó, Csaba

    2017-01-01

    A detailed ambient gamma dose equivalent rate mapping based on field measurements at ground level and at 1 m height was carried out at 142 sites in 80 × 90 km area in Pest County, Hungary. Detailed digital image processing analysis was carried out to identify and characterise spatial features such as outlying points, anomalous zones and linear edges in a smoothed TIN interpolated surface. The applied method proceeds from the simple shaded relief model and digital cross-sections to the more complex gradient magnitude and gradient direction maps, 2nd derivative profile curvature map, relief map and lineament density map. Each map is analysed for statistical characteristics and histogram-based image segmentation is used to delineate areas homogeneous with respect to the parameter values in these maps. Assessment of spatial anisotropy is implemented by 2D autocorrelogram and directional variogram analyses. The identified spatial features are related to underlying geological and tectonic conditions using GIS technology. Results show that detailed digital image processing is efficient in revealing the pattern present in field-measured ambient gamma dose equivalent rates and they are related to regional scale tectonic zones and surface sedimentary lithological conditions in the study area.

  2. Calibration Report for the WRAP Facility Gamma Energy Analysis System [104-ND-06-102A

    SciTech Connect

    WILLS, C.E.

    2000-02-15

    The Waste Receiving And Processing facility (WRAP) adheres to providing gamma-ray spectroscopy instrument calibrations traceable to the National Institute for Standards and Technology (NIST) standards. The detectors are used to produce quantitative results for the Waste Isolation Pilot Plant (WIPP) and must meet calibration programmatic calibration goals. Instruments must meet portions of ANSI N42.14, 1978 guide for Germanium detectors. The Non-Destructive Assay (NDA) Gamma Energy Analysis (GEA) utilizes NIST traceable line source standards for the detector system calibrations. The counting configuration is a series of drums containing the line sources and different density filler matrices. The drums are used to develop system efficiencies with respect to density. The efficiency and density correction factors are required for the processing of drummed waste materials of similar densities. The calibration verification is carried out after the calibration is deemed final, by counting a second drum of NIST traceable sources. Three in-depth calibrations have been completed on one of the two systems to date, the first being the system acceptance plan. This report has a secondary function; that being the development of the instrument calibration errors which are to be folded into the Total Instrument Uncertainty document, HNF-4050.

  3. Calibration Report for the WRAP Facility Gamma Energy Analysis System (104-ND-06-102A)

    SciTech Connect

    WILLS, C.E.

    2000-03-13

    The Waste Receiving And Processing facility (WRAP) adheres to providing gamma-ray spectroscopy instrument calibrations traceable to the National Institute for Standards and Technology (NIST) standard{sup (4)}. The detectors are used to produce quantitative results for the Waste Isolation Pilot Plant (WIPP) and must meet calibration programmatic calibration goals. Instruments must meet portions of ANSI N42.14, 1978 guide for Germanium detectors. The Non-Destructive Assay (NDA) Gamma Energy Analysis (GEA) utilizes NIST traceable line source standards for the detector system calibrations. The counting configuration is a series of drums containing the line sources and different density filler matrices. The drums are used to develop system efficiencies with respect to density. The efficiency and density correction factors are required for the processing of drummed waste materials of similar densities. The calibration verification is carried out after the calibration is deemed final, by counting a second drum of NIST traceable sources. Three in-depth calibrations have been completed on one of the two systems to date, the first being the system acceptance plan. This report has a secondary function; that being the development of the instrument calibration errors which are to be folded into the Total Instrument Uncertainty document, HNF-4050.

  4. 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.

  5. 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.

  6. Analysis of the x-ray spectrum emitted by laser-produced plasma of dysprosium

    SciTech Connect

    Marcus, Gilad; Louzon, Einat; Henis, Zohar; Maman, Shlomo; Mandelbaum, Pinchas

    2007-05-15

    A detailed analysis of the x-ray spectrum (5-10.2 A ring ) emitted by laser-produced plasma of dysprosium (Dy) is given using ab initio calculations with the HULLAC relativistic code and isoelectronic trends. Resonance 3d-4p, 3d-nf (n=4 to 7), 3p-4s, and 3p-4d transitions of Ni I-like Dy XXXIX and neighboring ion satellite transitions (from Dy XXXIV to Dy XL) are identified.

  7. Multiwavelength and polarimetric analysis of the flat spectrum radio quasars 3C 273 and 3C 279

    NASA Astrophysics Data System (ADS)

    Fernandes, Sunil Anthony

    This dissertation presents results of multiwavelength analyses of 3C 273 and 3C 279. The main goals were to identify the gamma-ray emission region and dominant high-energy emission processes. Our methodology consisted of analyzing light curves from radio to gamma-rays over 6 - 8 years and polarimetric, spectral and line emission behavior. In 3C 279, we found that the emission from millimeter to ultraviolet was simultaneous and therefore co-spatial. We identified two active states where different high-energy emission processes were dominant. We found multiwavelength flaring events consistent with component ejections and shocks. We proposed that the gamma-ray emission region changed over time based on observations of both simultaneous and delayed gamma-rays emission with respect to low-energy emission during different time-frames. In 3C 273, we identified a non-thermal flare related to a component ejection and a thermal flare related to accretion. From reverberation mapping we found that the broad line region dynamical behavior over time possibly affects the derived supermassive black hole mass. In both objects we found that the gamma-ray spectral index was variable, and a trend of harder spectral index with higher gamma-ray luminosity. From the identification of different dominant high-energy emission processes, we concluded that the dominant high-energy emission mechanism changes with time. Overall, we concluded that similar results from both objects points to behavior that is potentially common to flat spectrum radio quasars. Increasing the sample size of objects analyzed with similar methodologies will provide more results to confirm or refine our conclusions.

  8. Multiwavelength and Polarimetric Analysis of the Flat Spectrum Radio Quasars 3C 273 and 3C 279

    NASA Astrophysics Data System (ADS)

    Fernandes, Sunil; Patiño-Álvarez, Victor; Chavushyan, Vahram; Schlegel, Eric M.; Lopez-Rodriguez, Enrique; León-Tavares, Jonathan; Carrasco, Luis; Valdés, José; Carramiñana, Alberto

    2017-01-01

    This poster presents results of multiwavelength analyses of 3C 273 and 3C 279. The main goals were to identify the gamma-ray emission region and dominant high-energy emission processes. Our methodology consisted of analyzing light curves from radio to gamma-rays over 6 - 8 years and polarimetric, spectral and line emission behavior.In 3C 279, we found that the emission from millimeter to ultraviolet was simultaneous and therefore co-spatial. We identified two active states where different high-energy emission processes were dominant. We found multiwavelength flaring events consistent with component ejections and shocks. We proposed that the gamma-ray emission region changed over time based on observations of both simultaneous and delayed gamma-rays emission with respect to low-energy emission during different time-frames.In 3C 273, we identified a non-thermal flare related to a component ejection and a thermal flare related to accretion. From reverberation mapping we found that the broad line region dynamical behavior over time possibly affects the derived supermassive black hole mass.In both objects we found that the gamma-ray spectral index was variable, and a trend of harder spectral index with higher gamma-ray luminosity. From the identification of different dominant high-energy emission processes, we concluded that the dominant high-energy emission mechanism changes with time. Overall, we concluded that similar results from both objects points to behavior that is potentially common to flat spectrum radio quasars. Increasing the sample size of objects analyzed with similar methodologies will provide more results to confirm or refine our conclusions.

  9. [Tobacco quality analysis of producing areas of Yunnan tobacco using near-infrared (NIR) spectrum].

    PubMed

    Wang, Yi; Ma, Xiang; Wen, Ya-Dong; Yu, Chun-Xia; Wang, Luo-Ping; Zhao, Long-Lian; Li, Jun-Hui

    2013-01-01

    In the present study, tobacco quality analysis of different producing areas was carried out applying spectrum projection and correlation methods. The group of industrial classification data was near-infrared (NIR) spectrum in 2010 year of middle parts of tobacco plant from Hongta Tobacco (Group) Co., Ltd. Twelve hundred seventy six superior tobacco leaf samples were collected from four producing areas, in which three areas from Yuxi, Chuxiong and Zhaotong, in Yunnan province all belong to tobacco varieties of K326 and one area from Dali belongs to tobacco varieties of Hongda. The conclusion showed that when the samples were divided into two parts by the ratio of 2 : 1 randomly as analysis and verification sets, the verification set corresponded with the analysis set applying spectrum projection because their correlation coefficients by the first and second dimensional projection were all above 0.99. At the same time, The study discussed a method to get the quantitative similarity values of different producing areas samples. The similarity values were instructive in tobacco plant planning, quality management, acquisition of raw materials of tobacco and tobacco leaf blending.

  10. Investigation and development of a high spectral resolution coherent optical spectrum analysis system.

    PubMed

    Feng, Kunpeng; Cui, Jiwen; Dang, Hong; Zhao, Shiyuan; Wu, Weidong; Tan, Jiubin

    2016-10-31

    Focusing on high resolution optical spectroscopy, a coherent optical spectrum analysis (COSA) system is investigated in this paper. Principle is built to demonstrate the operation of COSA and its signal processing in both time and frequency domain. According to COSA principle, resolution bandwidth (RBW) filters are found to have significant influence on power accuracy and spectral resolution of the optical spectrum analysis (OSA). Much effort is paid to design RBW filters, including center frequency, bandwidth and type of filters. Two RBW filters are optimized to reduce the power uncertainty of different spectral resolution and satisfy different signal under test. Then, simulations and experiments are conducted to verify COSA principle and results show that the power uncertainty is less than 0.5% and 1.2% for high and medium spectral resolution application, respectively. Finally, experiments on the OSA of actual spectra indicate that COSA system can achieve a 6 MHz spectral resolution and has an excellent capacity in analysis of fine spectrum structures.

  11. 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.

  12. Analysis of New Orion Gamma Ray Data and Monte Carlo Simulations of BATSE Gamma Ray Bursts. Part 1

    NASA Technical Reports Server (NTRS)

    Lingenfelter, Richard E.

    1998-01-01

    These studies were stimulated by the reported COMPTEL detection of nuclear gamma ray line emission from the Orion star formation region. Although the observation have very recently been retracted, the detailed analyses that we carried out clearly showed that the low energy cosmic rays that would have been required to explain the reported fluxes were exceedingly restrictive and thus highly improbable. Moreover, these studies proved to be the trigger for very productive new work. In particular, they led us into carefully re-examining the problem of the origin of the light elements, Li, Be and B, where we showed that the light elements could, in fact, be produced primarily by Galactic cosmic rays and did not require an unobserved low energy cosmic ray source , as had been suggested. We further showed that the observed abundances of Be and B in old halo stars contradicted the common belief that the Galactic cosmic rays were accelerated out of the well mixed interstellar medium, and required instead that they be accelerated out of freshly synthesized matter from supernovae. This work, in turn, led us to propose a new origin of Galactic cosmic rays from the refractory grains in supernova enriched cores of superbubbles.

  13. 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.

  14. Comparison of different fluorescence spectrum analysis techniques to characterize humification levels of waste-derived dissolved organic matter.

    PubMed

    Shao, L M; Zhang, C Y; He, P J; Lü, F

    2012-12-01

    In the present work, the humification level of waste-derived dissolved organic matter (DOM) at different waste biostability was investigated, by using fluorescent excitation-emission matrix (EEM) scanning. Different fluorescence spectrum analysis techniques were applied and compared. Experimental results demonstrate that parallel factor (PARAFAC) analysis was sensitive to reflect DOM humification, and the most reasonable to deconstruct DOM compositions, when compared with other spectrum analysis techniques. It suggests applying the DOM-EEM-PARAFAC pipeline for rapid estimation of waste biostability.

  15. 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…

  16. 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.

  17. Comparison of new and existing algorithms for the analysis of 2D radioxenon beta gamma spectra

    DOE PAGES

    Deshmukh, Nikhil; Prinke, Amanda; Miller, Brian; ...

    2017-01-13

    The aim of this study is to compare radioxenon beta–gamma analysis algorithms using simulated spectra with experimentally measured background, where the ground truth of the signal is known. We believe that this is among the largest efforts to date in terms of the number of synthetic spectra generated and number of algorithms compared using identical spectra. We generate an estimate for the minimum detectable counts for each isotope using each algorithm. The paper also points out a conceptual model to put the various algorithms into a continuum. Finally, our results show that existing algorithms can be improved and some newermore » algorithms can be better than the ones currently used.« less

  18. 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.

  19. [Research advances in water quality monitoring technology based on UV-Vis spectrum analysis].

    PubMed

    Wei, Kang-Lin; Wen, Zhi-yu; Wu, Xin; Zhang, Zhong-Wei; Zeng, Tian-Ling

    2011-04-01

    The application of spectral analysis to water quality monitoring is an important developing trend in the field of modern environment monitoring technology. The principle and characteristic of water quality monitoring technology based on UV-Vis spectrum analysis are briefly reviewed. And the research status and advances are introduced from two aspects, on-line monitoring and in-situ monitoring. Moreover, the existent key technical problems are put forward. Finally, the technology trends of multi-parameter water quality monitoring microsystem and microsystem networks based on microspectrometer are prospected, which has certain reference value for the research and development of environmental monitoring technology and modern scientific instrument in the authors' country.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Regularized least-squares migration of simultaneous-source seismic data with adaptive singular spectrum analysis.

    PubMed

    Li, Chuang; Huang, Jian-Ping; Li, Zhen-Chun; Wang, Rong-Rong

    2017-01-01

    Simultaneous-source acquisition has been recognized as an economic and efficient acquisition method, but the direct imaging of the simultaneous-source data produces migration artifacts because of the interference of adjacent sources. To overcome this problem, we propose the regularized least-squares reverse time migration method (RLSRTM) using the singular spectrum analysis technique that imposes sparseness constraints on the inverted model. Additionally, the difference spectrum theory of singular values is presented so that RLSRTM can be implemented adaptively to eliminate the migration artifacts. With numerical tests on a flat layer model and a Marmousi model, we validate the superior imaging quality, efficiency and convergence of RLSRTM compared with LSRTM when dealing with simultaneous-source data, incomplete data and noisy data.

  5. Analysis of ELF electromagnetic field pulses recorded by the Hylaty station coinciding with terrestrial gamma-ray flashes

    NASA Astrophysics Data System (ADS)

    Kulak, A.; Mlynarczyk, J.; Ostrowski, M.; Kubisz, J.; Michalec, A.

    2012-09-01

    Terrestrial gamma-ray flashes (TGFs) were registered the first time by the NASA's Compton Gamma Ray Observatory. The physical mechanism of TGF generation is not fully known, but there is a consensus among researchers that the radiation is produced by bremsstrahlung of relativistic electrons in the thunderstorm regions of the atmosphere. Therefore, TGFs have been linked to positive-polarity intracloud lightning discharges, strong positive cloud-to-ground discharges or upward discharges from a thundercloud top. The currently operating Fermi Gamma-ray Space Telescope is equipped with a Gamma-ray Burst Monitor that can detect terrestrial gamma-ray flashes. It opens up a new possibility to search for lightning discharges responsible for TGFs. Ground-based lightning monitoring systems in the ELF, LF and VLF ranges can be used for that purpose. The ELF systems are especially useful, since they provide a large monitoring range of several thousand kilometers for strong atmospheric discharges (charge moments above several tens of C km). In this paper we have described the data analysis method for ELF electromagnetic field pulses and applied it to study our first examples of TGFs registered by Fermi GBM coinciding with ELF pulses recorded by the Hylaty ELF station located in the Carpathian Mountains in Poland. Using our ELF electromagnetic wave propagation model we have evaluated charge moments for the two registered events to be 320 and 110 C km and provided upper limits for the remaining events.

  6. Contralateral parahippocampal gamma-band activity determines noise-like tinnitus laterality: a region of interest analysis.

    PubMed

    Vanneste, S; Heyning, P Van de; Ridder, D De

    2011-12-29

    Tinnitus is described as an auditory perception in the absence of any external sound source. Tinnitus loudness has been correlated to sustained high frequency gamma-band activity in auditory cortex. It remains unknown whether unilateral tinnitus is always generated in the left auditory cortex, irrespective of the side on which the tinnitus is perceived, or in the contralateral auditory cortex. In order to solve this enigma source localized electroencephalographic (EEG) recordings of a homogenous group of unilateral left and right-sided tinnitus patients presenting with noise-like tinnitus was analyzed. Based on a region of interest analysis, the most important result of this study is that tinnitus lateralization depended on the gamma-band activity of the contralateral parahippocampal area. As for the auditory cortex no differences were found between left-sided and right-sided tinnitus patients. However, in comparison to a control group both left and right-sided tinnitus patients had an increased gamma-band activity in both the left and right primary and secondary auditory cortex. Thus whereas in tinnitus the primary and secondary auditory cortices of both sides are characterized by increased gamma-band activity, the side on which the tinnitus is perceived relates to gamma-band activity in the contralateral parahippocampal area.

  7. 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.

  8. Lipidomic analysis reveals a radiosensitizing role of gamma-linolenic acid in glioma cells.

    PubMed

    Antal, Otilia; Péter, Mária; Hackler, László; Mán, Imola; Szebeni, Gábor; Ayaydin, Ferhan; Hideghéty, Katalin; Vigh, László; Kitajka, Klára; Balogh, Gábor; Puskás, Laszló G

    2015-09-01

    Previous studies have demonstrated that gamma-linolenic acid (GLA) is effective against glioma cells under both in vitro and in vivo conditions. In the present study we determined how GLA alone or in combination with irradiation alters the fatty acid (FA) and lipid profiles, the lipid droplet (LD) content, the lipid biosynthetic gene expression and the apoptosis of glioma cells. In GLA-treated cells direct correlations were found between the levels of various FAs and the expression of the corresponding FA biosynthetic genes. The total levels of saturated and monosaturated FAs decreased in concert with the down-regulation of FASN and SCD1 gene expression. Similarly, decreased FADS1 gene expression was paralleled by lowered arachidonic acid (20:4 n-6) and eicosapentaenoic acid (20:5 n-3) contents, while the down-regulation of FADS2 expression was accompanied by a diminished docosahexaenoic acid (22:6 n-3) content. Detailed mass spectrometric analyses revealed that individual treatments gave rise to distinct lipidomic fingerprints. Following uptake, GLA was subjected to elongation, resulting in dihomo-gamma-linolenic acid (20:3 n-6, DGLA), which was used for the synthesis of the LD constituent triacylglycerols and cholesteryl esters. Accordingly, an increased number of LDs were observed in response to GLA administration after irradiation. GLA increased the radioresponsiveness of U87 MG cells, as demonstrated by an increase in the number of apoptotic cells determined by FACS analysis. In conclusion, treatment with GLA increased the apoptosis of irradiated glioma cells, and GLA might therefore increase the therapeutic efficacy of irradiation in the treatment of gliomas.

  9. Yeast model analysis of novel polymerase gamma variants found in patients with autosomal recessive mitochondrial disease.

    PubMed

    Kaliszewska, Magdalena; Kruszewski, Jakub; Kierdaszuk, Biruta; Kostera-Pruszczyk, Anna; Nojszewska, Monika; Łusakowska, Anna; Vizueta, Joel; Sabat, Dorota; Lutyk, Dorota; Lower, Michał; Piekutowska-Abramczuk, Dorota; Kaniak-Golik, Aneta; Pronicka, Ewa; Kamińska, Anna; Bartnik, Ewa; Golik, Paweł; Tońska, Katarzyna

    2015-09-01

    Replication of the mitochondrial genome depends on the single DNA polymerase (pol gamma). Mutations in the POLG gene, encoding the catalytic subunit of the human polymerase gamma, have been linked to a wide variety of mitochondrial disorders that show remarkable heterogeneity, with more than 200 sequence variants, often very rare, found in patients. The pathogenicity and dominance status of many such mutations remain, however, unclear. Remarkable structural and functional conservation of human POLG and its S. cerevisiae ortholog (Mip1p) led to the development of many successful yeast models, enabling to study the phenotype of putative pathogenic mutations. In a group of patients with suspicion of mitochondrial pathology, we identified five novel POLG sequence variants, four of which (p.Arg869Ter, p.Gln968Glu, p.Thr1053Argfs*6, and p.Val1106Ala), together with one previously known but uncharacterised variant (p.Arg309Cys), were amenable to modelling in yeast. Familial analysis indicated causal relationship of these variants with disease, consistent with autosomal recessive inheritance. To investigate the effect of these sequence changes on mtDNA replication, we obtained the corresponding yeast mip1 alleles (Arg265Cys, Arg672Ter, Arg770Glu, Thr809Ter, and Val863Ala, respectively) and tested their effect on mitochondrial genome stability and replication fidelity. For three of them (Arg265Cys, Arg672Ter, and Thr809Ter), we observed a strong, partially dominant phenotype of a complete loss of functional mtDNA, whereas the remaining two led to partial mtDNA depletion and significant increase in point mutation frequencies. These results show good correlation with the severity of symptoms observed in patients and allow to establish these variants as pathogenic mutations.

  10. A calibration to predict the concentrations of impurities in plutonium oxide by prompt gamma analysis: Revision 1

    SciTech Connect

    Narlesky, Joshua E.; Foster, Lynn A.; Kelly, Elizabeth J.; Murray, Roy E., IV

    2009-12-01

    Over 5,500 containers of excess plutonium-bearing materials have been packaged for long-term storage following the requirements of DOE-STD- 3013. Knowledge of the chemical impurities in the packaged materials is important because certain impurities, such as chloride salts, affect the behavior of the material in storage leading to gas generation and corrosion when sufficient moisture also is present. In most cases, the packaged materials are not well characterized, and information about the chemical impurities is limited to knowledge of the material’s processing history. The alpha-particle activity from the plutonium and americium isotopes provides a method of nondestructive self-interrogation to identify certain light elements through the characteristic, prompt gamma rays that are emitted from alpha-particle-induced reactions with these elements. Gamma-ray spectra are obtained for each 3013 container using a highresolution, coaxial high-purity germanium detector. These gamma-ray spectra are scanned from 800 to 5,000 keV for characteristic, prompt gamma rays from the detectable elements, which include lithium, beryllium, boron, nitrogen, oxygen, fluorine, sodium, magnesium, aluminum, silicon, phosphorus, chlorine, and potassium. The lower limits of detection for these elements in a plutonium-oxide matrix increase with atomic number and range from 100 or 200 ppm for the lightest elements such as lithium and beryllium, to 19,000 ppm for potassium. The peak areas from the characteristic, prompt gamma rays can be used to estimate the concentration of the light-element impurities detected in the material on a semiquantitative basis. The use of prompt gamma analysis to assess impurity concentrations avoids the expense and the risks generally associated with performing chemical analysis on radioactive materials. The analyzed containers are grouped by impurity content, which helps to identify high-risk containers for surveillance and in sorting materials before packaging.

  11. [Bibliometrics analysis on researches of illness spectrum for acu-moxibustion therapy and prospect].

    PubMed

    Yang, Ming-Xiao; Zhao, Ling; Yang, Jie; Cao, Xin-Xin; Yu, Zu-Nian; Liang, Fan-Rong

    2014-06-01

    The research on indications of acu-moxibustion is very important for effectively guiding clinical practice. In the present paper, the authors retrieved domestic literature about researches on the disease-spectrum or indications of acu-moxibustion therapy in recent 10 years, and made a bibliometrics analysis according to the described research methods, publishing year, quantity and their proportionate relationship. A total of 18 qualified original papers involving 414 illnesses or clinical conditions were included in the present paper. Among the 414 kinds of clinical conditions or illnesses, 72 were considered to be suitable candidates for acu-moxibustion therapy, including functional dyspepsia, herpes zoster, irritable bowel syndrome, gastrointestinal dysfunction, scapulohumeral periarthritis, cervical syndrome, dyssomnia, acne (cyst type), chronic urticaria, regional neurodermatitis, pain, itching, etc. which belong to illness-spectrum grade-I. Generally, the acu-moxibustion therapy is, in clinical effects, relatively poorer for structural diseases which are attributed to grade-II or grade-III type. Nevertheless, the diversity of clinical indications of acu-moxibustion has been confirmed nowadays. Current studies on illness-spectrum are of certain uniformity and comprehensiveness, but need further extending and perfecting, and need more standardized methods corresponding to principles of the evidence-based medicine.

  12. Time-singularity multifractal spectrum distribution based on detrended fluctuation analysis

    NASA Astrophysics Data System (ADS)

    Xiong, Gang; Yu, Wenxian; Zhang, Shuning

    2015-11-01

    The time-singularity multifractal spectrum distribution (TS-MFSD) generalizes the singularity spectrum in a time-varying framework. In this paper, a new method to compute MFSD based on detrended fluctuation analysis (DFA-MFSD) is introduced. We relate DFA-MFSD method to the standard partition function based multifractal spectrum distribution formalism, and prove that both approaches are equivalent for fractal time series with compact support. Furthermore, we find that DFA-MFSD has equivalent results, better mathematic foundation, less computational cost and is more adapted for fractal time series with arbitrary length, compared with MFSD based on wavelet transform modulus maxima (WTMM-MFSD). By analyzing several examples, this paper shows that DFAm-MFSD with different polynomial fitting orders can reliably determine the time-varying multifractal scaling behavior of time series, including processes embodying chirp-type or oscillating singularities. To illustrate these results, simulations are executed using binomial multiplicative cascades, wavelet series and real sea clutter, and simulations indicate that DFA m-MFSD benefits from excellent theoretical and practical performances.

  13. 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)

  14. Resequencing and Association Analysis of PTPRA, a Possible Susceptibility Gene for Schizophrenia and Autism Spectrum Disorders

    PubMed Central

    Xing, Jingrui; Wang, Chenyao; Kimura, Hiroki; Takasaki, Yuto; Kunimoto, Shohko; Yoshimi, Akira; Nakamura, Yukako; Koide, Takayoshi; Banno, Masahiro; Kushima, Itaru; Uno, Yota; Okada, Takashi; Aleksic, Branko; Ikeda, Masashi; Iwata, Nakao; Ozaki, Norio

    2014-01-01

    Background The PTPRA gene, which encodes the protein RPTP-α, is critical to neurodevelopment. Previous linkage studies, genome-wide association studies, controlled expression analyses and animal models support an association with both schizophrenia and autism spectrum disorders, both of which share a substantial portion of genetic risks. Methods We sequenced the protein-encoding areas of the PTPRA gene for single nucleotide polymorphisms or small insertions/deletions (InDel) in 382 schizophrenia patients. To validate their association with the disorders, rare (minor allele frequency <1%), missense mutations as well as one InDel in the 3′UTR region were then genotyped in another independent sample set comprising 944 schizophrenia patients, 336 autism spectrum disorders patients, and 912 healthy controls. Results Eight rare mutations, including 3 novel variants, were identified during the mutation-screening phase. In the following association analysis, L59P, one of the two missense mutations, was only observed among patients of schizophrenia. Additionally, a novel duplication in the 3′UTR region, 174620_174623dupTGAT, was predicted to be located within a Musashi Binding Element. Major Conclusions No evidence was seen for the association of rare, missense mutations in the PTPRA gene with schizophrenia or autism spectrum disorders; however, we did find some rare variants with possibly damaging effects that may increase the susceptibility of carriers to the disorders. PMID:25393624

  15. "Chiron": A Proposed Remote Sensing Prompt Gamma Ray Activation Analysis Instrument for a Nuclear Powered Prometheus Mission

    NASA Technical Reports Server (NTRS)

    Floyd, Samuel R.; Keller, John W.; Dworkin, Jason P.; Mildner, David F. R.

    2004-01-01

    Prompt Gamma Ray Activation Analysis (PGAA) from neutron capture is an important experimental method that yields information on the elemental abundance of target materials. Gamma ray analysis has been used in planetary exploration missions by taking advantage of the production of neutrons as a result of Galactic Cosmic Ray interaction within the planetary surfaces. The .gamma ray signal that can be obtained from the GCR production of neutrons is very low, so we seek a superior neutron source. NASA s Project Prometheus and the Dept. of Energy aim to develop a nuclear power system for planetary exploration. This provides us with a tremendous opportunity to harness the reactor as a source of neutrons that can be used for PGAA. We envision a narrow stream of neutrons from the reactor directed toward the surface of an asteroid or comet producing the prompt gamma ray signal for analysis. Under ideal conditions of neutron flux and spacecraft orbit, both the signal strength and the spatial resolution will improved by several orders of magnitude over previously missions.

  16. 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.

  17. Feasibility study of prompt gamma neutron activation analysis (PGNAA) of explosives simulants and bulk material using DD/DT neutron generator

    NASA Astrophysics Data System (ADS)

    Bishnoi, S.; Sarkar, P. S.; Patel, T.; Adhikari, P. S.; Sinha, Amar

    2013-04-01

    Elemental characterization of low Z elements (C,H,Cl,Fe) inside bulk materials were performed using PGNAA technique. Samples having elemental composition similar to explosives were used for such experimentations using moderated DD neutrons as well as DT(14MeV) neutrons. We could observe characteristic prompt capture gamma rays of hydrogen (2.224MeV), nitrogen (10.83 MeV), chlorine (6.11 MeV) and Fe (6.02MeV and 7.63MeV) also (n,n'γ) prompt gamma signal (4.43MeV) of carbon. BGO detector has been used for gamma spectrum acquisition. These experimentations has been carried out for initial feasibility studies of detecting prompt gamma lines as a part of PGNAA technique based explosive detection system development. A detail description of experimental set up and procedure has been discussed in paper.

  18. Enhanced Gamma Oscillatory Activity in Rats with Chronic Inflammatory Pain

    PubMed Central

    Wang, Jing; Wang, Jing; Xing, Guo-Gang; Li, Xiaoli; Wan, You

    2016-01-01

    It has been reported that oscillatory gamma activity participates in brief acute pain and tonic ongoing pain. It is of great interest to determine whether the gamma activity is involved in chronic pain since chronic pain is a more severe pathological condition characterized by pain persistency. To investigate the oscillatory gamma activity in chronic pain, in the present study, we recorded spontaneous electrocorticogram (ECoG) signals during chronic pain development in rats with chronic inflammatory pain induced by monoarthritis. Power spectrum analysis of ECoG data showed that gamma power increased significantly at the late stage of chronic inflammatory pain. The increased gamma activity occurred mainly at electrodes over primary somatosensory cortices. In rats with chronic pain, the gamma power was positively correlated with the hyperalgesia measured by laser energy that elicited hindpaw withdrawal response. Furthermore, an increased coupling between the amplitude of gamma power and the phase of theta oscillations was observed in chronic inflammatory pain condition. These results indicate an enhanced spontaneous gamma activity in chronic pain and suggest a potential biomarker for the severity of chronic pain. PMID:27847461

  19. [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.

  20. 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.

  1. Heart rate monitoring from wrist-type PPG based on singular spectrum analysis with motion decision.

    PubMed

    Yang Wang; Zhiwen Liu; Bin Dong

    2016-08-01

    Heart rate (HR) monitoring is necessary for daily healthcare. Wrist-type photoplethsmography (PPG) is a convenient and non-invasive technique for HR monitoring. However, motion artifacts (MA) caused by subjects' movements can extremely interfere the results of HR monitoring. In this paper, we propose a high accuracy method using motion decision, singular spectrum analysis (SSA) and spectral peak searching for daily HR estimation. The proposed approach was evaluated on 8 subjects under a series of different motion states. Compared with electrocardiogram (ECG) recorded simultaneously, the experimental results indicated that the averaged absolute estimation error was 2.33 beats per minute (BPM).

  2. Asymmetry Spectrum Analysis of ADCP Data and Characterization of Tidal Currents Non-Stationary Dynamics

    NASA Astrophysics Data System (ADS)

    Rosa, R.; Viana, M.; Barbosa, E.; Vijaykumar, N.; Menezes, V.; Zanandrea, A.; Bolzan, M.; Ramos, F.

    The northeast Brazilian shelf is characterized by the presence of a rich suite of quartz sand bedforms having heights of 3-10 m and 100-4000 m crest lengths which are clearly visible by satellite imagery up to 40 m depth The impact of the kilometer-scale bedform fields generated by currents and waves in a time scale of decades to centuries strongly modifies ocean circulation patterns in the shallow shelf through bottom interactions Recent analysis of the tidal band obtained from the Acoustic Doppler Current Profiler ADCP data suggests the presence of a nonlinear interaction of the subtidal and the tidal variability In this paper the tidal and long-period bands are analyzed from sep 2000 to nov 2001 from a hybrid approach combining the gradient pattern analysis and discrete wavelet decomposition The asymmetry spectrum amplitude asymmetries versus characteristic frequencies is a robust and alternative method for short time series complex variability characterization From the asymmetry spectrum slope the underlying dynamics as turbulence deterministic chaos reaction-diffusion and hybrid regimes can be well characterized From this analysis it can be stated that a reactive-diffusive regime can be responsible for the intermittency and coherent structures present observed in non-stationary multi-scaling tidal currents dynamics In the context of these results new insights on remote sensing improvements related to fine characterization of tidal current extended dynamics are discussed

  3. An Optoelectronic Equivalent Narrowband Filter for High Resolution Optical Spectrum Analysis

    PubMed Central

    Feng, Kunpeng; Cui, Jiwen; Dang, Hong; Wu, Weidong; Sun, Xun; Jiang, Xuelin; Tan, Jiubin

    2017-01-01

    To achieve a narrow bandwidth optical filter with a wide swept range for new generation optical spectrum analysis (OSA) of high performance optical sensors, an optoelectronic equivalent narrowband filter (OENF) was investigated and a swept optical filter with bandwidth of several MHz and sweep range of several tens of nanometers was built using electric filters and a sweep laser as local oscillator (LO). The principle of OENF is introduced and analysis of the OENF system is presented. Two electric filters are optimized to be RBW filters for high and medium spectral resolution applications. Both simulations and experiments are conducted to verify the OENF principle and the results show that the power uncertainty is less than 1.2% and the spectral resolution can reach 6 MHz. Then, a real-time wavelength calibration system consisting of a HCN gas cell and Fabry–Pérot etalon is proposed to guarantee a wavelength accuracy of ±0.4 pm in the C-band and to reduce the influence of phase noise and nonlinear velocity of the LO sweep. Finally, OSA experiments on actual spectra of various optical sensors are conducted using the OENF system. These experimental results indicate that OENF system has an excellent capacity for the analysis of fine spectrum structures. PMID:28208624

  4. An Optoelectronic Equivalent Narrowband Filter for High Resolution Optical Spectrum Analysis.

    PubMed

    Feng, Kunpeng; Cui, Jiwen; Dang, Hong; Wu, Weidong; Sun, Xun; Jiang, Xuelin; Tan, Jiubin

    2017-02-10

    To achieve a narrow bandwidth optical filter with a wide swept range for new generation optical spectrum analysis (OSA) of high performance optical sensors, an optoelectronic equivalent narrowband filter (OENF) was investigated and a swept optical filter with bandwidth of several MHz and sweep range of several tens of nanometers was built using electric filters and a sweep laser as local oscillator (LO). The principle of OENF is introduced and analysis of the OENF system is presented. Two electric filters are optimized to be RBW filters for high and medium spectral resolution applications. Both simulations and experiments are conducted to verify the OENF principle and the results show that the power uncertainty is less than 1.2% and the spectral resolution can reach 6 MHz. Then, a real-time wavelength calibration system consisting of a HCN gas cell and Fabry-Pérot etalon is proposed to guarantee a wavelength accuracy of ±0.4 pm in the C-band and to reduce the influence of phase noise and nonlinear velocity of the LO sweep. Finally, OSA experiments on actual spectra of various optical sensors are conducted using the OENF system. These experimental results indicate that OENF system has an excellent capacity for the analysis of fine spectrum structures.

  5. 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.

  6. Gamma-Ray Interactions for Reachback Analysts

    SciTech Connect

    Karpius, Peter Joseph; Myers, Steven Charles

    2016-08-02

    This presentation is a part of the DHS LSS spectroscopy training course and presents an overview of the following concepts: identification and measurement of gamma rays; use of gamma counts and energies in research. Understanding the basic physics of how gamma rays interact with matter can clarify how certain features in a spectrum were produced.

  7. Whole-Genome Sequencing in Microbial Forensic Analysis of Gamma-Irradiated Microbial Materials.

    PubMed

    Broomall, Stacey M; Ait Ichou, Mohamed; Krepps, Michael D; Johnsky, Lauren A; Karavis, Mark A; Hubbard, Kyle S; Insalaco, Joseph M; Betters, Janet L; Redmond, Brady W; Rivers, Bryan A; Liem, Alvin T; Hill, Jessica M; Fochler, Edward T; Roth, Pierce A; Rosenzweig, C Nicole; Skowronski, Evan W; Gibbons, Henry S

    2015-11-13

    Effective microbial forensic analysis of materials used in a potential biological attack requires robust methods of morphological and genetic characterization of the attack materials in order to enable the attribution of the materials to potential sources and to exclude other potential sources. The genetic homogeneity and potential intersample variability of many of the category A to C bioterrorism agents offer a particular challenge to the generation of attributive signatures, potentially requiring whole-genome or proteomic approaches to be utilized. Currently, irradiation of mail is standard practice at several government facilities judged to be at particularly high risk. Thus, initial forensic signatures would need to be recovered from inactivated (nonviable) material. In the study described in this report, we determined the effects of high-dose gamma irradiation on forensic markers of bacterial biothreat agent surrogate organisms with a particular emphasis on the suitability of genomic DNA (gDNA) recovered from such sources as a template for whole-genome analysis. While irradiation of spores and vegetative cells affected the retention of Gram and spore stains and sheared gDNA into small fragments, we found that irradiated material could be utilized to generate accurate whole-genome sequence data on the Illumina and Roche 454 sequencing platforms.

  8. Experimental and vector analysis on gamma type Stirling engine with hot power cylinder

    SciTech Connect

    Isshiki, Naotsugu; Tsukahara, Shigeji; Ohtomo, Michihiro

    1995-12-31

    In 1993, the superiority of hot end connected power cylinder gamma type Stirling engine (HEC) compared to the conventional cold end connected power cylinder engine (CEC) was reported by Prof. J.Kentfield of the University of Calgary. It is a great thing that he introduced the HEC engine, and it reminded the authors that in 1980, they built and experimented with a three cylinder 3kW Stirling engine SRI-1, in which two cylinders are positively heated by gas, that is called HCH (Hot, Cold and Hot) engine as shown in a figure, and having similarity to the above HEC. The authors have developed a quite simple and understandable approximate harmonic vector analysis method for Stirling machines. By this, Kentfield`s HEC engine and their HCH engine are expressed by the same figure as shown in the paper. The similarity and superiority of HEC and HCH compared to CEC and CHC are easily shown by the vector analysis method with physical reason.

  9. Whole-Genome Sequencing in Microbial Forensic Analysis of Gamma-Irradiated Microbial Materials

    PubMed Central

    Broomall, Stacey M.; Ait Ichou, Mohamed; Krepps, Michael D.; Johnsky, Lauren A.; Karavis, Mark A.; Hubbard, Kyle S.; Insalaco, Joseph M.; Betters, Janet L.; Redmond, Brady W.; Rivers, Bryan A.; Liem, Alvin T.; Hill, Jessica M.; Fochler, Edward T.; Roth, Pierce A.; Rosenzweig, C. Nicole; Skowronski, Evan W.

    2015-01-01

    Effective microbial forensic analysis of materials used in a potential biological attack requires robust methods of morphological and genetic characterization of the attack materials in order to enable the attribution of the materials to potential sources and to exclude other potential sources. The genetic homogeneity and potential intersample variability of many of the category A to C bioterrorism agents offer a particular challenge to the generation of attributive signatures, potentially requiring whole-genome or proteomic approaches to be utilized. Currently, irradiation of mail is standard practice at several government facilities judged to be at particularly high risk. Thus, initial forensic signatures would need to be recovered from inactivated (nonviable) material. In the study described in this report, we determined the effects of high-dose gamma irradiation on forensic markers of bacterial biothreat agent surrogate organisms with a particular emphasis on the suitability of genomic DNA (gDNA) recovered from such sources as a template for whole-genome analysis. While irradiation of spores and vegetative cells affected the retention of Gram and spore stains and sheared gDNA into small fragments, we found that irradiated material could be utilized to generate accurate whole-genome sequence data on the Illumina and Roche 454 sequencing platforms. PMID:26567301

  10. Analysis of gamma radiation from a radon source: Indications of a solar influence

    NASA Astrophysics Data System (ADS)

    Sturrock, P. A.; Steinitz, G.; Fischbach, E.; Javorsek, D.; Jenkins, J. H.

    2012-08-01

    This article presents an analysis of about 29,000 measurements of gamma radiation associated with the decay of radon in a sealed container at the Geological Survey of Israel (GSI) Laboratory in Jerusalem between 28 January 2007 and 10 May 2010. These measurements exhibit strong variations in time of year and time of day, which may be due in part to environmental influences. However, time-series analysis reveals a number of periodicities, including two at approximately 11.2 year-1 and 12.5 year-1. We have previously found these oscillations in nuclear-decay data acquired at the Brookhaven National Laboratory and at the Physiklisch-Technische Bundesanstalt, and we have suggested that these oscillations are attributable to some form of solar radiation that has its origin in the deep solar interior. A curious property of the GSI data is that the annual oscillation is much stronger in daytime data than in nighttime data, but the opposite is true for all other oscillations. This may be a systematic effect but, if it is not, this property should help narrow the theoretical options for the mechanism responsible for decay-rate variability.

  11. 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.

  12. [Determination of content and specific activity of radioactive elements in phosphate slag by spectral and energy spectrum analysis].

    PubMed

    Bao, P Y

    2001-10-01

    Phosphate slag is the slag discarded after phosphate ore is smelted. The content and specific activity of radioactive elements in slag must be determined accurately for environmental protection and comprehensive utilization. This paper discusses how IR spectrum and X-ray diffraction method are used to study its components. The main phase composition is glassy slag. The samples are decomposed with HF-HNO3-HClO4. After anion-exchange separation, arsenazo III is used to determine the content of uranium and thorium in slag. The average content of U is 32.11 micrograms.g-1 and 8.5 micrograms.g-1 for Th. gamma spectrum is used to determine the specific activity of radioactive nuclear elements in it. The specific activities of 226Ra, 232Th and 40K are 112 +/- 2.0% Bq.kg-1, 18.8 +/- 6.4% Bq.kg-1 and 77.6 +/- 3.7% Bq.kg-1, respectively. The values are calculated as follow: M(Ra) = 0.6 Bq.kg-1, M gamma = 0.5 Bq.kg-1. The results show that the values are below 1.0 Bq.kg-1, which is stipulated by national GB6566-86 standard for radioactivity of building materials. The slag is therefore can be utilized to produce slag cement. This provides theoretical basis for the treatment of it.

  13. Grid search in stellar parameters: a software for spectrum analysis of single stars and binary systems

    NASA Astrophysics Data System (ADS)

    Tkachenko, A.

    2015-09-01

    Context. The currently operating space missions, as well as those that will be launched in the near future, will deliver high-quality data for millions of stellar objects. Since the majority of stellar astrophysical applications still (at least partly) rely on spectroscopic data, an efficient tool for the analysis of medium- to high-resolution spectroscopy is needed. Aims: We aim at developing an efficient software package for the analysis of medium- to high-resolution spectroscopy of single stars and those in binary systems. The major requirements are that the code should have a high performance, represent the state-of-the-art analysis tool, and provide accurate determinations of atmospheric parameters and chemical compositions for different types of stars. Methods: We use the method of atmosphere models and spectrum synthesis, which is one of the most commonly used approaches for the analysis of stellar spectra. Our Grid Search in Stellar Parameters (gssp) code makes use of the Message Passing Interface (OpenMPI) implementation, which makes it possible to run in parallel mode. The method is first tested on the simulated data and is then applied to the spectra of real stellar objects. Results: The majority of test runs on the simulated data were successful in that we were able to recover the initially assumed sets of atmospheric parameters. We experimentally find the limits in signal-to-noise ratios of the input spectra, below which the final set of parameters is significantly affected by the noise. Application of the gssp package to the spectra of three Kepler stars, KIC 11285625, KIC 6352430, and KIC 4931738, was also largely successful. We found an overall agreement of the final sets of the fundamental parameters with the original studies. For KIC 6352430, we found that dependence of the light dilution factor on wavelength cannot be ignored, as it has a significant impact on the determination of the atmospheric parameters of this binary system. Conclusions: The

  14. Hot background” of the mobile inelastic neutron scattering system for soil carbon analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The problem of gamma spectrum peaks identification arises when conducting soil carbon (and other elements) analysis using the mobile inelastic neutron scattering (MINS) system. Some gamma spectrum peaks could be associated with radioisotopes appearing due to neutron activation of both the MINS syste...

  15. 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

  16. Dynamics Evolution Investigation of Mack Mode Instability in a Hypersonic Boundary Layer by Bicoherence Spectrum Analysis

    NASA Astrophysics Data System (ADS)

    Han, Jian; Jiang, Nan

    2012-07-01

    The instability of a hypersonic boundary layer on a cone is investigated by bicoherence spectrum analysis. The experiment is conducted at Mach number 6 in a hypersonic wind tunnel. The time series signals of instantaneous fluctuating surface-thermal-flux are measured by Pt-thin-film thermocouple temperature sensors mounted at 28 stations on the cone surface along streamwise direction to investigate the development of the unstable disturbances. The bicoherence spectrum analysis based on wavelet transform is employed to investigate the nonlinear interactions of the instability of Mack modes in hypersonic laminar boundary layer transition. The results show that wavelet bicoherence is a powerful tool in studying the unstable mode nonlinear interaction of hypersonic laminar-turbulent transition. The first mode instability gives rise to frequency shifts to higher unstable modes at the early stage of hypersonic laminar-turbulent transition. The modulations subsequently lead to the second mode instability occurrence. The second mode instability governs the last stage of instability and final breakdown to turbulence with multi-scale disturbances growth.

  17. Quantitative analysis of volatiles in edible oils following accelerated oxidation using broad spectrum isotope standards.

    PubMed

    Gómez-Cortés, Pilar; Sacks, Gavin L; Brenna, J Thomas

    2015-05-01

    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 oxidised 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 <50mg/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 labelled standards for quantitative characterisation of processing-induced volatile generation across related foodstuffs, and verify the origin of specific volatiles from parent n-3 fatty acids.

  18. Comparison of template-matching and singular-spectrum-analysis methods for imaging implanted brachytherapy seeds.

    PubMed

    Alam, S Kaisar; Mamou, Jonathan; Feleppa, Ernest J; Kalisz, Andrew; Ramachandran, Sarayu

    2011-11-01

    Brachytherapy using small implanted radioactive seeds is becoming an increasingly popular method for treating prostate cancer, in which a radiation oncologist implants seeds in the prostate transperineally under ultrasound guidance. Dosimetry software determines the optimal placement of seeds for achieving the prescribed dose based on ultrasonic determination of the gland boundaries. However, because of prostate movement and distortion during the implantation procedure, some seeds may not be placed in the desired locations; this causes the delivered dose to differ from the prescribed dose. Current ultrasonic imaging methods generally cannot depict the implanted seeds accurately. We are investigating new ultrasonic imaging methods that show promise for enhancing the visibility of seeds and thereby enabling real-time detection and correction of seed-placement errors during the implantation procedure. Real-time correction of seed-placement errors will improve the therapeutic radiation dose delivered to target tissues. In this work, we compare the potential performance of a template-matching method and a previously published method based on singular spectrum analysis for imaging seeds. In particular, we evaluated how changes in seed angle and position relative to the ultrasound beam affect seed detection. The conclusion of the present study is that singular spectrum analysis has better sensitivity but template matching is more resistant to false positives; both perform well enough to make seed detection clinically feasible over a relevant range of angles and positions. Combining the information provided by the two methods may further reduce ambiguities in determining where seeds are located.

  19. Stress analysis, thermomechanical fatique evaluation, and root subcomponent testing of gamma/gamma prime-delta eutectic alloy

    NASA Technical Reports Server (NTRS)

    Sheffler, K. D.; Jackson, J. J.

    1976-01-01

    Thermomechanical fatigue (TMF) and root subcomponent tensile, creep, and low cycle fatigue (LCF) tests were conducted to determine the capability of a fully lamellar directionally solidified eutectic alloy to sustain the airfoil thermal fatigue and root attachment loads anticipated in advanced, hollow, high work turbine blades. A three dimensional finite element elastic stress analysis was performed on typical advanced hollow eutectic airfoil and root-platform designs to determine appropriate conditions for these tests. Results of TMF tests conducted on longitudinal specimens (stress axis parallel to the solidification direction) containing a simulated leading edge cooling hole pattern indicated the longitudinal TMF properties to be more than adequate for the particular advanced hollow blade analyzed, with the strain range for a 10,000 cycle life being more than 50% above the maximum strain range calculated for the advanced hollow blade.

  20. Gamma-ray luminosity and photon index evolution of FSRQ blazars and contribution to the gamma-ray background

    SciTech Connect

    Singal, J.; Ko, A.; Petrosian, V.

    2014-05-10

    We present the redshift evolutions and distributions of the gamma-ray luminosity and photon spectral index of flat spectrum radio quasar (FSRQ) type blazars, using non-parametric methods to obtain the evolutions and distributions directly from the data. The sample we use for analysis consists of almost all FSRQs observed with a greater than approximately 7σ detection threshold in the first-year catalog of the Fermi Gamma-ray Space Telescope's Large Area Telescope, with redshifts as determined from optical spectroscopy by Shaw et al. We find that FSQRs undergo rapid gamma-ray luminosity evolution, but negligible photon index evolution, with redshift. With these evolutions accounted for we determine the density evolution and luminosity function of FSRQs and calculate their total contribution to the extragalactic gamma-ray background radiation, resolved and unresolved, which is found to be 16(+10/–4)%, in agreement with previous studies.