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Sample records for gamma detection system

  1. Portable compton gamma-ray detection system

    DOEpatents

    Rowland, Mark S.; Oldaker, Mark E.

    2008-03-04

    A Compton scattered gamma-ray detector system. The system comprises a gamma-ray spectrometer and an annular array of individual scintillators. The scintillators are positioned so that they are arrayed around the gamma-ray spectrometer. The annular array of individual scintillators includes a first scintillator. A radiation shield is positioned around the first scintillator. A multi-channel analyzer is operatively connected to the gamma-ray spectrometer and the annular array of individual scintillators.

  2. Gamma detectors in explosives and narcotics detection systems

    NASA Astrophysics Data System (ADS)

    Bystritsky, V. M.; Zubarev, E. V.; Krasnoperov, A. V.; Porohovoi, S. Yu.; Rapatskii, V. L.; Rogov, Yu. N.; Sadovskii, A. B.; Salamatin, A. V.; Salmin, R. A.; Slepnev, V. M.; Andreev, E. I.

    2013-11-01

    Gamma detectors based on BGO crystals were designed and developed at the Joint Institute for Nuclear Research. These detectors are used in explosives and narcotics detection systems. Key specifications and design features of the detectors are presented. A software temperature-compensation method that makes it possible to stabilize the gamma detector response and operate the detector in a temperature range from -20 to 50°C is described.

  3. Gamma scintillator system using boron carbide for neutron detection

    NASA Astrophysics Data System (ADS)

    Ben-Galim, Y.; Wengrowicz, U.; Raveh, A.; Orion, I.

    2014-08-01

    A new approach for neutron detection enhancement to scintillator gamma-ray detectors is suggested. By using a scintillator coupled with a boron carbide (B4C) disc, the 478 keV gamma-photon emitted from the excited Li in 94% of the 10B(n,α)7Li interactions was detected. This suggests that the performance of existing gamma detection systems in Homeland security applications can be improved. In this study, a B4C disc (2 in. diameter, 0.125 in. thick) with ~19.8% 10B was used and coupled with a scintillator gamma-ray detector. In addition, the neutron thermalization moderator was studied in order to be able to increase the neutron sensitivity. An improvement in the detector which is easy to assemble, affordable and efficient was demonstrated. Furthermore, a tailored Monte-Carlo code written in MATLAB was developed for validation of the proposed application through efficiency estimation for thermal neutrons. Validation of the code was accomplished by showing that the MATLAB code results were well correlated to a Monte-Carlo MCNP code results. The measured efficiency of the assembled experimental model was observed to be in agreement with both models calculations.

  4. Minimum Detectable Activity for Tomographic Gamma Scanning System

    SciTech Connect

    Venkataraman, Ram; Smith, Susan; Kirkpatrick, J. M.; Croft, Stephen

    2015-01-01

    For any radiation measurement system, it is useful to explore and establish the detection limits and a minimum detectable activity (MDA) for the radionuclides of interest, even if the system is to be used at far higher values. The MDA serves as an important figure of merit, and often a system is optimized and configured so that it can meet the MDA requirements of a measurement campaign. The non-destructive assay (NDA) systems based on gamma ray analysis are no exception and well established conventions, such the Currie method, exist for estimating the detection limits and the MDA. However, the Tomographic Gamma Scanning (TGS) technique poses some challenges for the estimation of detection limits and MDAs. The TGS combines high resolution gamma ray spectrometry (HRGS) with low spatial resolution image reconstruction techniques. In non-imaging gamma ray based NDA techniques measured counts in a full energy peak can be used to estimate the activity of a radionuclide, independently of other counting trials. However, in the case of the TGS each “view” is a full spectral grab (each a counting trial), and each scan consists of 150 spectral grabs in the transmission and emission scans per vertical layer of the item. The set of views in a complete scan are then used to solve for the radionuclide activities on a voxel by voxel basis, over 16 layers of a 10x10 voxel grid. Thus, the raw count data are not independent trials any more, but rather constitute input to a matrix solution for the emission image values at the various locations inside the item volume used in the reconstruction. So, the validity of the methods used to estimate MDA for an imaging technique such as TGS warrant a close scrutiny, because the pair-counting concept of Currie is not directly applicable. One can also raise questions as to whether the TGS, along with other image reconstruction techniques which heavily intertwine data, is a suitable method if one expects to measure samples whose activities

  5. Networked gamma radiation detection system for tactical deployment

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sanjoy; Maurer, Richard; Wolff, Ronald; Smith, Ethan; Guss, Paul; Mitchell, Stephen

    2015-08-01

    A networked gamma radiation detection system with directional sensitivity and energy spectral data acquisition capability is being developed by the National Security Technologies, LLC, Remote Sensing Laboratory to support the close and intense tactical engagement of law enforcement who carry out counterterrorism missions. In the proposed design, three clusters of 2″ × 4″ × 16″ sodium iodide crystals (4 each) with digiBASE-E (for list mode data collection) would be placed on the passenger side of a minivan. To enhance localization and facilitate rapid identification of isotopes, advanced smart real-time localization and radioisotope identification algorithms like WAVRAD (wavelet-assisted variance reduction for anomaly detection) and NSCRAD (nuisance-rejection spectral comparison ratio anomaly detection) will be incorporated. We will test a collection of algorithms and analysis that centers on the problem of radiation detection with a distributed sensor network. We will study the basic characteristics of a radiation sensor network and focus on the trade-offs between false positive alarm rates, true positive alarm rates, and time to detect multiple radiation sources in a large area. Empirical and simulation analyses of critical system parameters, such as number of sensors, sensor placement, and sensor response functions, will be examined. This networked system will provide an integrated radiation detection architecture and framework with (i) a large nationally recognized search database equivalent that would help generate a common operational picture in a major radiological crisis; (ii) a robust reach back connectivity for search data to be evaluated by home teams; and, finally, (iii) a possibility of integrating search data from multi-agency responders.

  6. Radiation detection system for portable gamma-ray spectroscopy

    DOEpatents

    Rowland, Mark S.; Howard, Douglas E.; Wong, James L.; Jessup, James L.; Bianchini, Greg M.; Miller, Wayne O.

    2006-06-20

    A portable gamma ray detection apparatus having a gamma ray detector encapsulated by a compact isolation structure having at least two volumetrically-nested enclosures where at least one is a thermal shield. The enclosures are suspension-mounted to each other to successively encapsulate the detector without structural penetrations through the thermal shields. A low power cooler is also provided capable of cooling the detector to cryogenic temperatures without consuming cryogens, due to the heat load reduction by the isolation structure and the reduction in the power requirements of the cooler. The apparatus also includes a lightweight portable power source for supplying power to the apparatus, including to the cooler and the processing means, and reducing the weight of the apparatus to enable handheld operation or toting on a user's person.

  7. Innovative Gamma Ray Spectrometer Detection Systems for Conducting Scanning Surveys on Challenging Terrain - 13583

    SciTech Connect

    Palladino, Carl; Mason, Bryan; Engle, Matt; LeVangie, James; Dempsey, Gregg; Klemovich, Ron

    2013-07-01

    The Santa Susana Field Laboratory located near Simi Valley, California was investigated to determine the nature and extent of gamma radiation anomalies. The primary objective was to conduct gamma scanning surveys over 100 percent of the approximately 1,906,000 square meters (471 acre) project site with the most sensitive detection system possible. The site had challenging topography that was not conducive to traditional gamma scanning detection systems. Terrain slope varied from horizontal to 48 degrees and the ground surface ranged from flat, grassy meadows to steep, rocky hillsides. In addition, the site was home to many protected endangered plant and animal species, and archaeologically significant sites that required minimal to no disturbance of the ground surface. Therefore, four innovative and unique gamma ray spectrometer detection systems were designed and constructed to successfully conduct gamma scanning surveys of approximately 1,076,000 square meters (266 acres) of the site. (authors)

  8. Neutron interrogation system using high gamma ray signature to detect contraband special nuclear materials in cargo

    DOEpatents

    Slaughter, Dennis R.; Pohl, Bertram A.; Dougan, Arden D.; Bernstein, Adam; Prussin, Stanley G.; Norman, Eric B.

    2008-04-15

    A system for inspecting cargo for the presence of special nuclear material. The cargo is irradiated with neutrons. The neutrons produce fission products in the special nuclear material which generate gamma rays. The gamma rays are detecting indicating the presence of the special nuclear material.

  9. Determination of the optimal positions for installing gamma ray detection systems at Tehran Research Reactor

    NASA Astrophysics Data System (ADS)

    Sayyah, A.; Rahmani, F.; Khalafi, H.

    2015-09-01

    Dosimetric instruments must constantly monitor radiation dose levels in different areas of nuclear reactor. Tehran Research Reactor (TRR) has seven beam tubes for different research purposes. All the beam tubes extend from the reactor core to Beam Port Floor (BPF) of the reactor facility. During the reactor operation, the gamma rays exiting from each beam tube outlet produce a specific gamma dose rate field in the space of the BPF. To effectively monitor the gamma dose rates on the BPF, gamma ray detection systems must be installed in optimal positions. The selection of optimal positions is a compromise between two requirements. First, the installation positions must possess largest gamma dose rates and second, gamma ray detectors must not be saturated in these positions. In this study, calculations and experimental measurements have been carried out to identify the optimal positions of the gamma ray detection systems. Eight three dimensional models of the reactor core and related facilities corresponding to eight scenarios have been simulated using MCNPX Monte Carlo code to calculate the gamma dose equivalent rate field in the space of the BPF. These facilities are beam tubes, thermal column, pool, BPF space filled with air, facilities such as neutron radiography facility, neutron powder diffraction facility embedded in the beam tubes as well as biological shields inserted into the unused beam tubes. According to the analysis results of the combined gamma dose rate field, three positions on the north side and two positions on the south side of the BPF have been recognized as optimal positions for installing the gamma ray detection systems. To ensure the consistency of the simulation data, experimental measurements were conducted using TLDs (600 and 700) pairs during the reactor operation at 4.5 MW.

  10. A Case Study Correlating Innovative Gamma Ray Scanning Detection Systems Data to Surface Soil Gamma Spectrometry Results - 13580

    SciTech Connect

    Thompson, Shannon; Rodriguez, Rene; Billock, Paul; Lit, Peter

    2013-07-01

    HydroGeoLogic (HGL), Inc. completed a United States Environmental Protection Agency (USEPA) study to characterize radiological contamination at a site near Canoga Park, California. The characterized area contained 470 acres including the site of a prototype commercial nuclear reactor and other nuclear design, testing, and support operations from the 1950's until 1988 [1]. The site history included radiological releases during operation followed by D and D activities. The characterization was conducted under an accelerated schedule and the results will support the project remediation. The project has a rigorous cleanup to background agenda and does not allow for comparison to risk-based guidelines. To target soil sample locations, multiple lines of evidence were evaluated including a gamma radiation survey, geophysical surveys, historical site assessment, aerial photographs, and former worker interviews. Due to the time since production and decay, the primary gamma emitting radionuclide remaining is cesium-137 (Cs-137). The gamma ray survey covered diverse, rugged terrain using custom designed sodium iodide thallium-activated (NaI(Tl)) scintillation detection systems. The survey goals included attaining 100% ground surface coverage and detecting gamma radiation as sensitively as possible. The effectiveness of innovative gamma ray detection systems was tested by correlating field Cs-137 static count ratios to Cs-137 laboratory gamma spectrometry results. As a case study, the area encompassing the former location of the first nuclear power station in the U. S. was scanned, and second by second global positioning system (GPS)-linked gamma spectral data were evaluated by examining total count rate and nuclide-specific regions of interest. To compensate for Compton scattering from higher energy naturally occurring radionuclides (U-238, Th-232 and their progeny, and K-40), count rate ratios of anthropogenic nuclide-specific regions of interest to the total count rate were

  11. Detection system for high-resolution gamma radiation spectroscopy with neutron time-of-flight filtering

    DOEpatents

    Dioszegi, Istvan; Salwen, Cynthia; Vanier, Peter

    2014-12-30

    A .gamma.-radiation detection system that includes at least one semiconductor detector such as HPGe-Detector, a position-sensitive .alpha.-Detector, a TOF Controller, and a Digitizer/Integrator. The Digitizer/Integrator starts to process the energy signals of a .gamma.-radiation sent from the HPGe-Detector instantly when the HPGe-Detector detects the .gamma.-radiation. Subsequently, it is determined whether a coincidence exists between the .alpha.-particles and .gamma.-radiation signal, based on a determination of the time-of-flight of neutrons obtained from the .alpha.-Detector and the HPGe-Detector. If it is determined that the time-of-flight falls within a predetermined coincidence window, the Digitizer/Integrator is allowed to continue and complete the energy signal processing. If, however, there is no coincidence, the Digitizer/Integrator is instructed to be clear and reset its operation instantly.

  12. GammaScorpion: mobile gamma-ray tomography system for early detection of basal stem rot in oil palm plantations

    NASA Astrophysics Data System (ADS)

    Abdullah, Jaafar; Hassan, Hearie; Shari, Mohamad Rabaie; Mohd, Salzali; Mustapha, Mahadi; Mahmood, Airwan Affendi; Jamaludin, Shahrizan; Ngah, Mohd Rosdi; Hamid, Noor Hisham

    2013-03-01

    Detection of the oil palm stem rot disease Ganoderma is a major issue in estate management and production in Malaysia. Conventional diagnostic techniques are difficult and time consuming when using visual inspection, and destructive and expensive when based on the chemical analysis of root or stem tissue. As an alternative, a transportable gamma-ray computed tomography system for the early detection of basal stem rot (BSR) of oil palms due to Ganoderma was developed locally at the Malaysian Nuclear Agency, Kajang, Malaysia. This system produces high quality tomographic images that clearly differentiate between healthy and Ganoderma infected oil palm stems. It has been successfully tested and used to detect the extent of BSR damage in oil palm plantations in Malaysia without the need to cut down the trees. This method offers promise for in situ inspection of oil palm stem diseases compared to the more conventional methods.

  13. An analysis of a spreader bar crane mounted gamma-ray radiation detection system

    NASA Astrophysics Data System (ADS)

    Grypp, Matthew David

    Over 95% of imports entering the United States from outside North America arrive via cargo containers by sea at 329 ports of entry. The current layered approach for the detection only scans 5% of cargo bound for the United States. This is inadequate to protect our country. This research involved the building of a gamma-ray radiation detection system used for cargo scanning. The system was mounted on a spreader bar crane (SBC) at the Port of Tacoma (PoT) and the applicability and capabilities of the system were analyzed. The detection system provided continuous count rate and spectroscopic data among three detectors while operating in an extreme environment. In a separate set of experiments, 60Co and 137Cs sources were positioned inside a cargo container and data were recorded for several count times. The Monte Carlo N-Particle (MCNP) code was used to simulate a radioactive source inside an empty cargo container and the results were compared to experimentally recorded data. The detection system demonstrated the ability to detect 60Co, 137Cs, 192 Ir, highly-enriched uranium (HEU), and weapons-grade plutonium (WGPu) with minimum detectable activities (MDA) of 5.9 +/- 0.4 microcuries (muCi), 19.3 +/- 1.1 muCi, 11.7 +/- 0.6 muCi, 3.5 +/- 0.3 kilograms (kg), and 30.6 +/- 1.3 grams (g), respectively. This system proved strong gamma-ray detection capabilities, but was limited in the detection of fissile materials Additional details of this system are presented and advantages of this approach to cargo scanning over current approaches are discussed.

  14. DEVELOPMENT OF DEPOSIT DETECTION SYSTEM IN PIPELINES OF THE STEELWORKS USING CS-137 GAMMA-RAY

    SciTech Connect

    Song, Won-Joon; Lee, Seung-Hee; Jeong, Hee-Dong

    2008-02-28

    The deposit is built up in the pipeline of the steelworks by the chemical reaction among COG (coke oven gas), BFG (blast furnace gas), moisture, and steel in the high temperature environment and obstructs the smooth gas flow. In this study a gamma-ray system is developed to detect the deposit accumulated in pipelines and calculate the accumulation rate with respect to the cross section area of pipes. Cs-137 is used as the gamma-ray source and the system is designed to apply to pipes of various diameters. This system also includes the DB for storage and display of the measurement results so that it can be used for the efficient management of the pipelines.

  15. Development of Deposit Detection System in Pipelines of the Steelworks Using CS-137 Gamma-Ray

    NASA Astrophysics Data System (ADS)

    Song, Won-Joon; Lee, Seung-Hee; Jeong, Hee-Dong

    2008-02-01

    The deposit is built up in the pipeline of the steelworks by the chemical reaction among COG (coke oven gas), BFG (blast furnace gas), moisture, and steel in the high temperature environment and obstructs the smooth gas flow. In this study a gamma-ray system is developed to detect the deposit accumulated in pipelines and calculate the accumulation rate with respect to the cross section area of pipes. Cs-137 is used as the gamma-ray source and the system is designed to apply to pipes of various diameters. This system also includes the DB for storage and display of the measurement results so that it can be used for the efficient management of the pipelines.

  16. Medium-resolution Autonomous in situ Gamma Detection System for Marine and Coastal Waters

    SciTech Connect

    Schwantes, Jon M.; Addleman, Raymond S.; Davidson, Joseph D.; Douglas, Matthew; Meier, David E.; Mullen, O Dennis; Myjak, Mitchell J.; Jones, Mark E.; Woodring, Mitchell L.; Johnson, Bryce; Santschi, Peter H.

    2009-12-01

    We are developing a medium-resolution autonomous in situ gamma detection system for marine and coastal waters. The system is designed to extract and preconcentrate isotopes of interest from natural waters prior to detection in order to eliminate signal attenuation of the gamma rays traveling through water and lower the overall background due to the presence of naturally occurring radioactive isotopes (40K and U/Th series radionuclides). Filtration is used to preconcentrate target isotopes residing on suspended particles, while chemosorption is employed to preferentially extract truly dissolved components from the water column. A variety of commercial and in-house nano-porus chemosorbents have been selected, procured or produced, and tested. Used filter and chemosorbent media are counted autonomously using two LaBr3 detectors in a near 4-pi configuration around the samples. A compact digital pulse processing system developed in-house and capable of running in coincidence mode is used to process the signal from the detectors to a small on-board computer. The entire system is extremely compact (9” dia. x 30” len.) and platform independent, but designed for initial deployment on a research buoy.

  17. LYNX: An unattended sensor system for detection of gamma-ray and neutron emissions from special nuclear materials

    SciTech Connect

    Runkle, Robert C.; Myjak, Mitchell J.; Kiff, Scott D.; Sidor, Daniel E.; Morris, Scott J.; Rohrer, John S.; Jarman, Kenneth D.; Pfund, David M.; Todd, Lindsay C.; Bowler, Ryan S.; Mullen, Crystal A.

    2009-01-21

    This manuscript profiles an unattended and fully autonomous detection system sensitive to gamma-ray and neutron emissions from special nuclear material. The LYNX design specifically targets applications that require radiation detection capabilities but possess little or no infrastructure. In these settings, users need the capability to deploy sensors for extended periods of time that analyze whatever signal-starved data can be captured, since little or no control may be exerted over measurement conditions. The fundamental sensing elements of the LYNX system are traditional NaI(Tl) and 3He detectors. The new developments reported here center on two themes: low-power electronics and computationally simple analysis algorithms capable of discriminating gamma-ray signatures indicative of special nuclear materials from those of naturally occurring radioactive material. Incorporating tripwire-detection algorithms based on gamma-ray spectral signatures into a low-power electronics package significantly improves performance in environments where sensors encounter nuisance sources.

  18. A dual neutron/gamma source for the Fissmat Inspection for Nuclear Detection (FIND) system.

    SciTech Connect

    Doyle, Barney Lee; King, Michael; Rossi, Paolo; McDaniel, Floyd Del; Morse, Daniel Henry; Antolak, Arlyn J.; Provencio, Paula Polyak; Raber, Thomas N.

    2008-12-01

    Shielded special nuclear material (SNM) is very difficult to detect and new technologies are needed to clear alarms and verify the presence of SNM. High-energy photons and neutrons can be used to actively interrogate for heavily shielded SNM, such as highly enriched uranium (HEU), since neutrons can penetrate gamma-ray shielding and gamma-rays can penetrate neutron shielding. Both source particles then induce unique detectable signals from fission. In this LDRD, we explored a new type of interrogation source that uses low-energy proton- or deuteron-induced nuclear reactions to generate high fluxes of mono-energetic gammas or neutrons. Accelerator-based experiments, computational studies, and prototype source tests were performed to obtain a better understanding of (1) the flux requirements, (2) fission-induced signals, background, and interferences, and (3) operational performance of the source. The results of this research led to the development and testing of an axial-type gamma tube source and the design/construction of a high power coaxial-type gamma generator based on the {sup 11}B(p,{gamma}){sup 12}C nuclear reaction.

  19. Shuttle flight test of an advanced gamma-ray detection system

    NASA Astrophysics Data System (ADS)

    Rester, Alfred C., Jr.

    1988-06-01

    The Gamma-Ray Advanced Detector (GRAD) is a gamma-ray detector system consisting of a large-volume, n-type germanium detector with active shielding of bismuth germanate and plastic scintillators. It was diverted from the AFP-675 program to a balloon flight over Antarctica following the Challenger Disaster and the discovery the following year of the supernova 1987A. The present report outlines activities leading to and following the decision to go to Antarctica and summarizes the basic technological results from the project.

  20. Efficiency calibration and minimum detectable activity concentration of a real-time UAV airborne sensor system with two gamma spectrometers.

    PubMed

    Tang, Xiao-Bin; Meng, Jia; Wang, Peng; Cao, Ye; Huang, Xi; Wen, Liang-Sheng; Chen, Da

    2016-04-01

    A small-sized UAV (NH-UAV) airborne system with two gamma spectrometers (LaBr3 detector and HPGe detector) was developed to monitor activity concentration in serious nuclear accidents, such as the Fukushima nuclear accident. The efficiency calibration and determination of minimum detectable activity concentration (MDAC) of the specific system were studied by MC simulations at different flight altitudes, different horizontal distances from the detection position to the source term center and different source term sizes. Both air and ground radiation were considered in the models. The results obtained may provide instructive suggestions for in-situ radioactivity measurements of NH-UAV. PMID:26773821

  1. Calibration of low-level beta-gamma coincidence detector systems for xenon isotope detection.

    PubMed

    Khrustalev, K; Wieslander, J S E; Auer, M; Gheddou, A

    2016-03-01

    The beta-gamma coincidence detector systems used for the measurement of the CTBT-relevant xenon isotopes (Xe-131m, Xe-133m, Xe-133 and Xe-135) in the International Monitoring System network and in the On-Site Inspection are reviewed. These detectors typically consist of a well-type or bore-through NaI crystal into which a measurement cell, serving also as a sample container, is inserted. This work describes the current calibration procedure for energy, resolution and efficiency, implementation challenges, availability and uncertainties of the specific nuclear decay data and the path forward to full calibration validation using GEANT4. PMID:26702548

  2. Development of Gamma-Ray Nondestructive Detection and Assay Systems for Nuclear Safeguards and Security at JAEA

    NASA Astrophysics Data System (ADS)

    Hajima, Ryoichi

    2015-10-01

    Nondestructive detection and assay of nuclide is one of the promising applications of energy-tunable gamma-rays from laser Compton scattering. In JAEA, we are developing technologies relevant to the gamma-ray non-destructive assay, which include a high-brightness gamma-ray source based on advanced laser and accelerator technologies and gamma-ray measurement techniques optimized for highly radioactive samples. In this paper, the status of the above R&D's is reviewed.

  3. Improved pulse shape discriminator for fast neutron-gamma ray detection system

    NASA Technical Reports Server (NTRS)

    Lockwood, J. A.; St. Onge, R.

    1969-01-01

    Discriminator in nuclear particle detection system distinguishes nuclear particle type and energy among many different nuclear particles. Discriminator incorporates passive, linear circuit elements so that it will operate over a wide dynamic range.

  4. Hand-held, mechanically cooled, radiation detection system for gamma-ray spectroscopy

    DOEpatents

    Burks, Morgan Thomas; Eckels, Joel Del

    2010-06-08

    In one embodiment, a radiation detection system is provided including a radiation detector and a first enclosure encapsulating the radiation detector, the first enclosure including a low-emissivity infra-red (IR) reflective coating used to thermally isolate the radiation detector. Additionally, a second enclosure encapsulating the first enclosure is included, the first enclosure being suspension mounted to the second enclosure. Further, a cooler capable of cooling the radiation detector is included. Still yet, a first cooling interface positioned on the second enclosure is included for coupling the cooler and the first enclosure. Furthermore, a second cooling interface positioned on the second enclosure and capable of coupling the first enclosure to a cooler separate from the radiation detection system is included. Other embodiments are also presented.

  5. Design of a spreader bar crane-mounted gamma-ray radiation detection system

    NASA Astrophysics Data System (ADS)

    Grypp, Matthew D.; Marianno, Craig M.; Poston, John W.; Hearn, Gentry C.

    2014-04-01

    Over 95% of imports entering the United States from outside North America arrive by sea at 329 ports of entry. These imports are packaged in more than 11 million cargo containers. Radiation portals monitors routinely scan cargo containers leaving port on specially-designed trucks. To accelerate the process, some commercial entities have placed detection systems on the spreader-bar cranes (SBCs) used to offload. Little is known about the radiation background profiles of systems operating on these cranes. To better understand the operational characteristics of these radiation detection systems; a research team from Texas A&M University (TAMU) mounted three thallium-doped sodium iodide [NaI(Tl)] detectors on an SBC at the Domestic Nuclear Detection Office's (DNDO) test track facility at the Port of Tacoma (PoT). These detectors were used to monitor background radiation levels and continuously recorded data during crane operations using a custom-built software package. Count rates and spectral data were recorded for various crane heights over both land and water. The results of this research created a background profile in which count rate was heavily dependent on position demonstrating how detector readings changed in the operational environment.

  6. Analysis of position error by time constant in read-out resistive network for gamma-ray imaging detection system

    NASA Astrophysics Data System (ADS)

    Jeon, Su-Jin; Park, Chang-In; Son, Byung-Hee; Jung, Mi; Jang, Teak-Jin; Lee, Chun-Sik; Choi, Young-Wan

    2016-03-01

    Position-sensitive photomultiplier tubes (PSPMTs) in array are used as gamma ray position detector. Each PMT converts the light of wide spectrum range (100 nm ~ 2500 nm) to electrical signal with amplification. Because detection system size is determined by the number of output channels in the PSPMTs, resistive network has been used for reducing the number of output channels. The photo-generated current is distributed to the four output current pulses according to a ratio by resistance values of resistive network. The detected positions are estimated by the peak value of the distributed current pulses. However, due to parasitic capacitance of PSPMTs in parallel with resistor in the resistive network, the time constants should be considered. When the duration of current pulse is not long enough, peak value of distributed pulses is reduced and detected position error is increased. In this paper, we analyzed the detected position error in the resistive network and variation of time constant according to the input position of the PSPMTs.

  7. Analysis of proposed gamma-ray detection system for the monitoring of core water inventory in a pressurized water reactor

    SciTech Connect

    Markoff, D.M.

    1987-12-01

    An initial study has been performed of the feasibility of employing an axial array of gamma detectors located outside the pressure vessel to monitor the coolant in a PWR. A one-dimensional transport analysis model is developed for the LOFT research reactor and for a mock-PWR geometry. The gamma detector response to coolant voiding in the core and downcomer has been determined for both geometries. The effects of various conditions (for example, time after shutdown, materials in the transport path, and the relative void fraction in different water regions) on the detector response are studied. The calculational results have been validated by a favorable comparison with LOFT experimental data. Within the limitations and approximations considered in the analysis, the results indicate that the gamma-ray detection scheme is able to unambiguously respond to changes in the coolant inventory within any vessel water region.

  8. Development of the multi-purpose gamma-ray detection system consisting of a double-sided silicon strip detector and a 25-segmented germanium detector

    NASA Astrophysics Data System (ADS)

    Lee, J. H.; Kim, N. Y.; Lee, C. S.; Jang, Z. H.

    2005-07-01

    We developed a position-sensitive gamma-ray detection system consisting of a double-sided silicon strip detector (DSSD) and a 25-segmented germanium detector (25-SEGD). Two major applications of the system are gamma-ray imaging (Compton camera) and linear polarization measurement for gamma rays emitted from oriented nuclei. Customized electronics were developed in order to handle multi-channel signals of both the DSSD and the 25-SEGD. Images for a 133Ba-based compound source in a square shape with areal dimensions of 1.5 × 1.5 mm2 are presented. Comparison between experimental images and a Monte Carlo simulation yielded the overall imaging resolution within 1 cm for the present system.

  9. Gamma-ray detected radio galaxies

    NASA Astrophysics Data System (ADS)

    Beckmann, Volker; Soldi, Simona; De Jong, Sandra; Kretschmer, Karsten; Savchenko, Volodymyr

    2016-07-01

    So far 15 radio galaxies have been detected in the gamma-ray domain by CGRO/EGRET and Fermi/LAT, with a few detections also in the VHE range. We search for distinguishing parameters and estimate the total number of gamma-ray emitting radio galaxies that are potentially detectable by Fermi/LAT. We use Fermi/LAT data in comparison with X-ray and hard X-ray data in order to constrain basic parameters such as the total power of the inverse Compton branch and the position of its peak. We search for possible correlations between the radio, UV, X-ray, and gamma-ray domain and derive the number counts distribution. We then compare their properties with those of the radio galaxies in the 3CRR and SMS4 catalogues. The data show no correlation between the peak of the inverse Compton emission and its luminosity. For the gamma-ray detected radio galaxies the luminosities in the various bands are correlated, except for the UV band, but there is no indication of a correlation of peak frequency or luminosity with the spectral slopes in the X-ray or gamma-ray band. The comparison with other bright radio galaxies shows that the gamma-ray detected objects are among those that have the largest X-ray but rather moderate radio fluxes. Their UV and X-ray luminosities are similar, but gamma-ray detected radio galaxies are predominantly of type FR-I, while the 3CRR sample contains mainly FR-II objects. The number counts of the so far gamma-ray detected radio galaxies shows a very shallow slope, indicating that potentially a fraction of radio galaxies has been missed so far or has not been identified as such, although the predicted number of 22 ± 7 is consistent with the observed 15 objects.

  10. The neutron-gamma Feynman variance to mean approach: Gamma detection and total neutron-gamma detection (theory and practice)

    NASA Astrophysics Data System (ADS)

    Chernikova, Dina; Axell, Kåre; Avdic, Senada; Pázsit, Imre; Nordlund, Anders; Allard, Stefan

    2015-05-01

    Two versions of the neutron-gamma variance to mean (Feynman-alpha method or Feynman-Y function) formula for either gamma detection only or total neutron-gamma detection, respectively, are derived and compared in this paper. The new formulas have particular importance for detectors of either gamma photons or detectors sensitive to both neutron and gamma radiation. If applied to a plastic or liquid scintillation detector, the total neutron-gamma detection Feynman-Y expression corresponds to a situation where no discrimination is made between neutrons and gamma particles. The gamma variance to mean formulas are useful when a detector of only gamma radiation is used or when working with a combined neutron-gamma detector at high count rates. The theoretical derivation is based on the Chapman-Kolmogorov equation with the inclusion of general reactions and corresponding intensities for neutrons and gammas, but with the inclusion of prompt reactions only. A one energy group approximation is considered. The comparison of the two different theories is made by using reaction intensities obtained in MCNPX simulations with a simplified geometry for two scintillation detectors and a 252Cf-source. In addition, the variance to mean ratios, neutron, gamma and total neutron-gamma are evaluated experimentally for a weak 252Cf neutron-gamma source, a 137Cs random gamma source and a 22Na correlated gamma source. Due to the focus being on the possibility of using neutron-gamma variance to mean theories for both reactor and safeguards applications, we limited the present study to the general analytical expressions for Feynman-alpha formulas.

  11. Real time wide area radiation surveillance system (REWARD) based on 3d silicon and (CD,ZN)Te for neutron and gamma-ray detection

    NASA Astrophysics Data System (ADS)

    Disch, C.

    2014-09-01

    Mobile surveillance systems are used to find lost radioactive sources and possible nuclear threats in urban areas. The REWARD collaboration [1] aims to develop such a complete radiation monitoring system that can be installed in mobile or stationary setups across a wide area. The scenarios include nuclear terrorism threats, lost radioactive sources, radioactive contamination and nuclear accidents. This paper will show the performance capabilities of the REWARD system in different scnarios. The results include both Monte Carlo simulations as well as neutron and gamma-ray detection performances in terms of efficiency and nuclide identification. The outcomes of several radiation mapping survey with the entire REWARD system will also be presented.

  12. Detecting axionlike particles with gamma ray telescopes.

    PubMed

    Hooper, Dan; Serpico, Pasquale D

    2007-12-01

    We propose that axionlike particles (ALPs) with a two-photon vertex, consistent with all astrophysical and laboratory bounds, may lead to a detectable signature in the spectra of high-energy gamma-ray sources. This occurs as a result of gamma rays being converted into ALPs in the magnetic fields of efficient astrophysical accelerators according to the "Hillas criterion", such as jets of active galactic nuclei or hot spots of radio galaxies. The discovery of such an effect is possible by GLAST in the 1-100 GeV range and by ground-based gamma-ray telescopes in the TeV range. PMID:18233353

  13. NEUTRON AND GAMMA RAY DETECTION FOR BORDER SECURITY APPLICATIONS

    SciTech Connect

    Kouzes, Richard T.

    2010-05-21

    Countries around the world are deploying radiation detection instrumentation to interdict the illegal shipment of radioactive material crossing international borders. These efforts include deployments in the U.S. and in a number of other countries by governments and international organizations. Most deployed radiation portal monitor systems are based on plastic scintillator for gamma-ray detection and 3He tubes for neutron detection. The approach to this homeland security application, and lessons learned, are discussed.

  14. Development of a novel gamma probe for detecting radiation direction

    NASA Astrophysics Data System (ADS)

    Pani, R.; Pellegrini, R.; Cinti, M. N.; Longo, M.; Donnarumma, R.; D'Alessio, A.; Borrazzo, C.; Pergola, A.; Ridolfi, S.; De Vincentis, G.

    2016-01-01

    Spatial localization of radioactive sources is currently a main issue interesting different fields, including nuclear industry, homeland security as well as medical imaging. It is currently achieved using different systems, but the development of technologies for detecting and characterizing radiation is becoming important especially in medical imaging. In this latter field, radiation detection probes have long been used to guide surgery, thanks to their ability to localize and quantify radiopharmaceutical uptake even deep in tissue. Radiolabelled colloid is injected into, or near to, the tumor and the surgeon uses a hand-held radiation detector, the gamma probe, to identify lymph nodes with radiopharmaceutical uptkake. The present work refers to a novel scintigraphic goniometric probe to identify gamma radiation and its direction. The probe incorporates several scintillation crystals joined together in a particular configuration to provide data related to the position of a gamma source. The main technical characteristics of the gamma locator prototype, i.e. sensitivity, spatial resolution and detection efficiency, are investigated. Moreover, the development of a specific procedure applied to the images permits to retrieve the source position with high precision with respect to the currently used gamma probes. The presented device shows a high sensitivity and efficiency to identify gamma radiation taking a short time (from 30 to 60 s). Even though it was designed for applications in radio-guided surgery, it could be used for other purposes, as for example homeland security.

  15. Gamma-ray binaries and related systems

    NASA Astrophysics Data System (ADS)

    Dubus, Guillaume

    2013-08-01

    After initial claims and a long hiatus, it is now established that several binary stars emit high- (0.1-100 GeV) and very high-energy (>100 GeV) gamma rays. A new class has emerged called "gamma-ray binaries", since most of their radiated power is emitted beyond 1 MeV. Accreting X-ray binaries, novae and a colliding wind binary ( η Car) have also been detected—"related systems" that confirm the ubiquity of particle acceleration in astrophysical sources. Do these systems have anything in common? What drives their high-energy emission? How do the processes involved compare to those in other sources of gamma rays: pulsars, active galactic nuclei, supernova remnants? I review the wealth of observational and theoretical work that have followed these detections, with an emphasis on gamma-ray binaries. I present the current evidence that gamma-ray binaries are driven by rotation-powered pulsars. Binaries are laboratories giving access to different vantage points or physical conditions on a regular timescale as the components revolve on their orbit. I explain the basic ingredients that models of gamma-ray binaries use, the challenges that they currently face, and how they can bring insights into the physics of pulsars. I discuss how gamma-ray emission from microquasars provides a window into the connection between accretion-ejection and acceleration, while η Car and novae raise new questions on the physics of these objects—or on the theory of diffusive shock acceleration. Indeed, explaining the gamma-ray emission from binaries strains our theories of high-energy astrophysical processes, by testing them on scales and in environments that were generally not foreseen, and this is how these detections are most valuable.

  16. Current trends in gamma radiation detection for radiological emergency response

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sanjoy; Guss, Paul; Maurer, Richard

    2011-09-01

    Passive and active detection of gamma rays from shielded radioactive materials, including special nuclear materials, is an important task for any radiological emergency response organization. This article reports on the current trends and status of gamma radiation detection objectives and measurement techniques as applied to nonproliferation and radiological emergencies. In recent years, since the establishment of the Domestic Nuclear Detection Office by the Department of Homeland Security, a tremendous amount of progress has been made in detection materials (scintillators, semiconductors), imaging techniques (Compton imaging, use of active masking and hybrid imaging), data acquisition systems with digital signal processing, field programmable gate arrays and embedded isotopic analysis software (viz. gamma detector response and analysis software [GADRAS]1), fast template matching, and data fusion (merging radiological data with geo-referenced maps, digital imagery to provide better situational awareness). In this stride to progress, a significant amount of inter-disciplinary research and development has taken place-techniques and spin-offs from medical science (such as x-ray radiography and tomography), materials engineering (systematic planned studies on scintillators to optimize several qualities of a good scintillator, nanoparticle applications, quantum dots, and photonic crystals, just to name a few). No trend analysis of radiation detection systems would be complete without mentioning the unprecedented strategic position taken by the National Nuclear Security Administration (NNSA) to deter, detect, and interdict illicit trafficking in nuclear and other radioactive materials across international borders and through the global maritime transportation-the so-called second line of defense.

  17. Current Trends in Gamma Radiation Detection for Radiological Emergency Response

    SciTech Connect

    Mukhopadhyay, S., Guss, P., Maurer, R.

    2011-09-01

    Passive and active detection of gamma rays from shielded radioactive materials, including special nuclear materials, is an important task for any radiological emergency response organization. This article reports on the current trends and status of gamma radiation detection objectives and measurement techniques as applied to nonproliferation and radiological emergencies. In recent years, since the establishment of the Domestic Nuclear Detection Office by the Department of Homeland Security, a tremendous amount of progress has been made in detection materials (scintillators, semiconductors), imaging techniques (Compton imaging, use of active masking and hybrid imaging), data acquisition systems with digital signal processing, field programmable gate arrays and embedded isotopic analysis software (viz. gamma detector response and analysis software [GADRAS]1), fast template matching, and data fusion (merging radiological data with geo-referenced maps, digital imagery to provide better situational awareness). In this stride to progress, a significant amount of interdisciplinary research and development has taken place–techniques and spin-offs from medical science (such as x-ray radiography and tomography), materials engineering (systematic planned studies on scintillators to optimize several qualities of a good scintillator, nanoparticle applications, quantum dots, and photonic crystals, just to name a few). No trend analysis of radiation detection systems would be complete without mentioning the unprecedented strategic position taken by the National Nuclear Security Administration (NNSA) to deter, detect, and interdict illicit trafficking in nuclear and other radioactive materials across international borders and through the global maritime transportation–the so-called second line of defense.

  18. Pulsed Photofission Delayed Gamma Ray Detection for Nuclear Material Identification

    SciTech Connect

    John Kavouras; Xianfei Wen; Daren R. Norman; Dante R. Nakazawa; Haori Yang

    2012-11-01

    Innovative systems with increased sensitivity and resolution are in great demand to detect diversion and to prevent misuse in support of nuclear materials management for the U.S. fuel cycle. Nuclear fission is the most important multiplicative process involved in non-destructive active interrogation. This process produces the most easily recognizable signature for nuclear materials. High-energy gamma rays can also excite a nucleus and cause fission through a process known as photofission. After photofission reactions, delayed signals are easily distinguishable from the interrogating radiation. Linac-based, advanced inspection techniques utilizing the fission signals after photofission have been extensively studied for homeland security applications. Previous research also showed that a unique delayed gamma ray energy spectrum exists for each fissionable isotope. Isotopic composition measurement methods based on delayed gamma ray spectroscopy will be the primary focus of this work.

  19. Detection of gamma rays from a starburst galaxy.

    PubMed

    Acero, F; Aharonian, F; Akhperjanian, A G; Anton, G; Barres de Almeida, U; Bazer-Bachi, A R; Becherini, Y; Behera, B; Bernlöhr, K; Bochow, A; Boisson, C; Bolmont, J; Borrel, V; Brucker, J; Brun, F; Brun, P; Bühler, R; Bulik, T; Büsching, I; Boutelier, T; Chadwick, P M; Charbonnier, A; Chaves, R C G; Cheesebrough, A; Chounet, L-M; Clapson, A C; Coignet, G; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubois, F; Dubus, G; Dyks, J; Dyrda, M; Egberts, K; Emmanoulopoulos, D; Espigat, P; Farnier, C; Fegan, S; Feinstein, F; Fiasson, A; Förster, A; Fontaine, G; Füssling, M; Gabici, S; Gallant, Y A; Gérard, L; Gerbig, D; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Göring, D; Hauser, D; Hauser, M; Heinz, S; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Hofverberg, P; Hoppe, S; Horns, D; Jacholkowska, A; de Jager, O C; Jahn, C; Jung, I; Katarzyński, K; Katz, U; Kaufmann, S; Kerschhaggl, M; Khangulyan, D; Khélifi, B; Keogh, D; Klochkov, D; Kluźniak, W; Kneiske, T; Komin, Nu; Kosack, K; Kossakowski, R; Lamanna, G; Lenain, J-P; Lohse, T; Marandon, V; Martineau-Huynh, O; Marcowith, A; Masbou, J; Maurin, D; McComb, T J L; Medina, M C; Méhault, J; Moderski, R; Moulin, E; Naumann-Godo, M; de Naurois, M; Nedbal, D; Nekrassov, D; Nicholas, B; Niemiec, J; Nolan, S J; Ohm, S; Olive, J-F; de Oña Wilhelmi, E; Orford, K J; Ostrowski, M; Panter, M; Paz Arribas, M; Pedaletti, G; Pelletier, G; Petrucci, P-O; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, A; Raubenheimer, B C; Raue, M; Rayner, S M; Reimer, O; Renaud, M; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Ruppel, J; Sahakian, V; Santangelo, A; Schlickeiser, R; Schöck, F M; Schwanke, U; Schwarzburg, S; Schwemmer, S; Shalchi, A; Sikora, M; Skilton, J L; Sol, H; Stawarz, Ł; Steenkamp, R; Stegmann, C; Stinzing, F; Superina, G; Szostek, A; Tam, P H; Tavernet, J-P; Terrier, R; Tibolla, O; Tluczykont, M; van Eldik, C; Vasileiadis, G; Venter, C; Venter, L; Vialle, J P; Vincent, P; Vivier, M; Völk, H J; Volpe, F; Wagner, S J; Ward, M; Zdziarski, A A; Zech, A

    2009-11-20

    Starburst galaxies exhibit in their central regions a highly increased rate of supernovae, the remnants of which are thought to accelerate energetic cosmic rays up to energies of approximately 10(15) electron volts. We report the detection of gamma rays--tracers of such cosmic rays--from the starburst galaxy NGC 253 using the High Energy Stereoscopic System (H.E.S.S.) array of imaging atmospheric Cherenkov telescopes. The gamma-ray flux above 220 billion electron volts is F = (5.5 +/- 1.0(stat) +/- 2.8(sys)) x 10(-13) cm(-2) s(-1), implying a cosmic-ray density about three orders of magnitude larger than that in the center of the Milky Way. The fraction of cosmic-ray energy channeled into gamma rays in this starburst environment is five times as large as that in our Galaxy. PMID:19779150

  20. Explosives detection system and method

    DOEpatents

    Reber, Edward L.; Jewell, James K.; Rohde, Kenneth W.; Seabury, Edward H.; Blackwood, Larry G.; Edwards, Andrew J.; Derr, Kurt W.

    2007-12-11

    A method of detecting explosives in a vehicle includes providing a first rack on one side of the vehicle, the rack including a neutron generator and a plurality of gamma ray detectors; providing a second rack on another side of the vehicle, the second rack including a neutron generator and a plurality of gamma ray detectors; providing a control system, remote from the first and second racks, coupled to the neutron generators and gamma ray detectors; using the control system, causing the neutron generators to generate neutrons; and performing gamma ray spectroscopy on spectra read by the gamma ray detectors to look for a signature indicative of presence of an explosive. Various apparatus and other methods are also provided.

  1. Composition and apparatus for detecting gamma radiation

    DOEpatents

    Hofstetter, K.J.

    1994-08-09

    A gamma radiation detector and a radioluminescent composition for use therein. The detector includes a radioluminescent composition that emits light in a characteristic wavelength region when exposed to gamma radiation, and means for detecting said radiation. The composition contains a scintillant such as anglesite (PbSO[sub 4]) or cerussite (PbCO[sub 3]) incorporated into an inert, porous glass matrix via a sol-gel process. Particles of radiation-sensitive scintillant are added to, a sol solution. The mixture is polymerized to form a gel, then dried under conditions that preserve the structural integrity and radiation sensitivity of the scintillant. The final product is a composition containing the uniformly-dispersed scintillant in an inert, optically transparent and highly porous matrix. The composition is chemically inert and substantially impervious to environmental conditions including changes in temperature, air pressure, and so forth. It can be fabricated in cylinders, blocks with holes therethrough for flow of fluid, sheets, surface coatings, pellets or other convenient shapes. 3 figs.

  2. Composition and apparatus for detecting gamma radiation

    DOEpatents

    Hofstetter, Kenneth J.

    1994-01-01

    A gamma radiation detector and a radioluminiscent composition for use therein. The detector includes a radioluminscent composition that emits light in a characteristic wavelength region when exposed to gamma radiation, and means for detecting said radiation. The composition contains a scintillant such as anglesite (PbSO.sub.4) or cerussite (PbCO.sub.3) incorporated into an inert, porous glass matrix via a sol-gel process. Particles of radiation-sensitive scintillant are added to, a sol solution. The mixture is polymerized to form a gel, then dried under conditions that preserve the structural integrity and radiation sensitivity of the scintillant. The final product is a composition containing the uniformly-dispersed scintillant in an inert, optically transparent and highly porous matrix. The composition is chemically inert and substantially impervious to environmental conditions including changes in temperature, air pressure, and so forth. It can be fabricated in cylinders, blocks with holes therethrough for flow of fluid, sheets, surface coatings, pellets or other convenient shapes.

  3. Plastic Gamma Sensors: An Application in Detection of Radioisotopes

    SciTech Connect

    S. Mukhopadhyay

    2003-06-01

    A brief survey of plastic scintillators for various radiation measurement applications is presented here. The utility of plastic scintillators for practical applications such as gamma radiation monitoring, real-time radioisotope detection and screening is evaluated in laboratory and field measurements. This study also reports results of Monte Carlo-type predictive responses of common plastic scintillators in gamma and neutron radiation fields. Small-size plastic detectors are evaluated for static and dynamic gamma-ray detection sensitivity of selected radiation sources.

  4. Current Trends in Gamma Ray Detection for Radiological Emergency Response

    SciTech Connect

    Mukhopadhyay, S., Guss, P., Maurer, R.

    2011-08-18

    Passive and active detection of gamma rays from shielded radioactive materials, including special nuclear materials, is an important task for any radiological emergency response organization. This article reports on the current trends and status of gamma radiation detection objectives and measurement techniques as applied to nonproliferation and radiological emergencies.

  5. ESA's Integral detects closest cosmic gamma-ray burst

    NASA Astrophysics Data System (ADS)

    2004-08-01

    should emit similar amounts of gamma-ray energy. The fraction of it detected at Earth should then depend on the 'width' (opening angle) and orientation of the beam as well as on the distance. The energy received should be larger when the beam is narrow or points towards us and smaller when the beam is broad or points away from us. New data collected with ESA's high energy observatories, Integral and XMM-Newton, now show that this picture is not so clear-cut and that the amount of energy emitted by GRBs can vary significantly. "The idea that all GRBs spit out the same amount of gamma rays, or that they are 'standard candles' as we call them, is simply ruled out by the new data," said Dr Sergey Sazonov, from the Space Research Institute of the Russian Academy of Sciences, Moscow (Russia) and the Max-Planck Institute for Astrophysics, Garching near Munich (Germany). Sazonov and an international team of researchers studied the GRB detected by Integral on 3 December 2003 and given the code-name of GRB 031203. Within a record 18 seconds of the burst, the Integral Burst Alert System had pinpointed the approximate position of GRB 031203 in the sky and sent the information to a network of observatories around the world. A few hours later one of them, ESA's XMM-Newton, determined a much more precise position for GRB 031203 and detected a rapidly fading X-ray source, which was subsequently seen by radio and optical telescopes on the ground. This wealth of data allowed astronomers to determine that GRB 031203 went off in a galaxy less than 1300 million light years away, making it the closest GRB ever observed. Even so, the way in which GRB 031203 dimmed with time and the distribution of its energy were not different from those of distant GRBs. Then, scientists started to realise that the concept of the 'standard candle' may not hold. "Being so close should make GRB 031203 appear very bright, but the amount of gamma-rays measured by Integral is about one thousand times less than what

  6. A system for simultaneous beta and gamma spectroscopy

    NASA Astrophysics Data System (ADS)

    Farsoni, A. T.; Hamby, D. M.

    2007-08-01

    A state-of-the-art radiation detection system for real-time and simultaneous spectroscopy of beta-particles and gamma-rays has been developed. The system utilizes a triple-layer phoswich detector and a customized Digital Pulse Processor (DPP) designed and built in our laboratory. The DPP board digitally captures the analog signal pulses and, following several digital preprocessing steps, transfers valid pulses to the host computer for further digital processing. A resolving algorithm also was developed to digitally discriminate beta and gamma events, and reconstruct separate beta and gamma-ray energy spectra with minimal crosstalk. The spectrometer has proven to be an effective tool for recording separate beta and gamma-ray spectra from mixed radiation fields. The system as a beta-gamma spectrometer will have broad-ranging applications in nuclear non-proliferation, radioactive waste management, worker safety, systems reliability, dose assessment, and risk analysis.

  7. Shuttle-flight test of an advanced gamma-ray detection system. Final report, 1 July 1983-31 July 1987

    SciTech Connect

    Rester, A.C.

    1988-06-30

    The Gamma-Ray Advanced Detector (GRAD) is a gamma-ray detector system consisting of a large-volume, n-type germanium detector with active shielding of bismuth germanate and plastic scintillators. It was diverted from the AFP-675 program to a balloon flight over Antarctica following the Challenger Disaster and the discovery the following year of the supernova 1987A. The present report outlines activities leading to and following the decision to go to Antarctica and summarizes the basic technological results from the project.

  8. Gamma-ray tracking method for pet systems

    DOEpatents

    Mihailescu, Lucian; Vetter, Kai M.

    2010-06-08

    Gamma-ray tracking methods for use with granular, position sensitive detectors identify the sequence of the interactions taking place in the detector and, hence, the position of the first interaction. The improved position resolution in finding the first interaction in the detection system determines a better definition of the direction of the gamma-ray photon, and hence, a superior source image resolution. A PET system using such a method will have increased efficiency and position resolution.

  9. Gamma and neutron detection modeling in the nuclear detection figure of merit (NDFOM) portal

    SciTech Connect

    Stroud, Phillip D; Saeger, Kevin J

    2009-01-01

    The Nuclear Detection Figure Of Merit (NDFOM) portal is a database of objects and algorithms for evaluating the performance of radiation detectors to detect nuclear material. This paper describes the algorithms used to model the physics and mathematics of radiation detection. As a first-principles end-to-end analysis system, it starts with the representation of the gamma and neutron spectral fluxes, which are computed with the particle and radiation transport code MCNPX. The gamma spectra emitted by uranium, plutonium, and several other materials of interest are described. The impact of shielding and other intervening material is computed by the method of build-up factors. The interaction of radiation with the detector material is computed by a detector response function approach. The construction of detector response function matrices based on MCNPX simulation runs is described in detail. Neutron fluxes are represented in a three group formulation to treat differences in detector sensitivities to thermal, epithermal, and fast neutrons.

  10. ESA's Integral detects closest cosmic gamma-ray burst

    NASA Astrophysics Data System (ADS)

    2004-08-01

    should emit similar amounts of gamma-ray energy. The fraction of it detected at Earth should then depend on the 'width' (opening angle) and orientation of the beam as well as on the distance. The energy received should be larger when the beam is narrow or points towards us and smaller when the beam is broad or points away from us. New data collected with ESA's high energy observatories, Integral and XMM-Newton, now show that this picture is not so clear-cut and that the amount of energy emitted by GRBs can vary significantly. "The idea that all GRBs spit out the same amount of gamma rays, or that they are 'standard candles' as we call them, is simply ruled out by the new data," said Dr Sergey Sazonov, from the Space Research Institute of the Russian Academy of Sciences, Moscow (Russia) and the Max-Planck Institute for Astrophysics, Garching near Munich (Germany). Sazonov and an international team of researchers studied the GRB detected by Integral on 3 December 2003 and given the code-name of GRB 031203. Within a record 18 seconds of the burst, the Integral Burst Alert System had pinpointed the approximate position of GRB 031203 in the sky and sent the information to a network of observatories around the world. A few hours later one of them, ESA's XMM-Newton, determined a much more precise position for GRB 031203 and detected a rapidly fading X-ray source, which was subsequently seen by radio and optical telescopes on the ground. This wealth of data allowed astronomers to determine that GRB 031203 went off in a galaxy less than 1300 million light years away, making it the closest GRB ever observed. Even so, the way in which GRB 031203 dimmed with time and the distribution of its energy were not different from those of distant GRBs. Then, scientists started to realise that the concept of the 'standard candle' may not hold. "Being so close should make GRB 031203 appear very bright, but the amount of gamma-rays measured by Integral is about one thousand times less than what

  11. Computer vision for detecting and quantifying gamma-ray sources in coded-aperture images

    SciTech Connect

    Schaich, P.C.; Clark, G.A.; Sengupta, S.K.; Ziock, K.P.

    1994-11-02

    The authors report the development of an automatic image analysis system that detects gamma-ray source regions in images obtained from a coded aperture, gamma-ray imager. The number of gamma sources in the image is not known prior to analysis. The system counts the number (K) of gamma sources detected in the image and estimates the lower bound for the probability that the number of sources in the image is K. The system consists of a two-stage pattern classification scheme in which the Probabilistic Neural Network is used in the supervised learning mode. The algorithms were developed and tested using real gamma-ray images from controlled experiments in which the number and location of depleted uranium source disks in the scene are known.

  12. Gamma spectrum unfolding for a NaI monitor of radioactivity in aquatic systems: experimental evaluations of the minimal detectable activity.

    PubMed

    Baré, J; Tondeur, F

    2011-08-01

    This paper deals with the experimental evaluation of the minimal detectable activity achievable by unfolding the gamma spectra of a NaI monitor. An aquatic monitor initially developed by the Institut des Radio-Eléments (IRE) is used for the application. Unfolding of the spectra is performed with GRAVEL, a UMG package code, on the basis of a response matrix obtained with MCNP5.1.40. Experimental data have been measured at IRE, in a 20m(3) seawater tank, for known activities of (137)Cs mixed with other gamma emitters ((40)K, (133)Ba, (113)Sn and (139)Ce). Deconvolution allows one to reduce the MDA of (137)Cs by an order of magnitude. PMID:21146415

  13. Apparatus and method for detecting gamma radiation

    DOEpatents

    Sigg, Raymond A.

    1994-01-01

    A high efficiency radiation detector for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data.

  14. Gamma-Ray Imaging for Explosives Detection

    NASA Technical Reports Server (NTRS)

    deNolfo, G. A.; Hunter, S. D.; Barbier, L. M.; Link, J. T.; Son, S.; Floyd, S. R.; Guardala, N.; Skopec, M.; Stark, B.

    2008-01-01

    We describe a gamma-ray imaging camera (GIC) for active interrogation of explosives being developed by NASA/GSFC and NSWCICarderock. The GIC is based on the Three-dimensional Track Imager (3-DTI) technology developed at GSFC for gamma-ray astrophysics. The 3-DTI, a large volume time-projection chamber, provides accurate, approx.0.4 mm resolution, 3-D tracking of charged particles. The incident direction of gamma rays, E, > 6 MeV, are reconstructed from the momenta and energies of the electron-positron pair resulting from interactions in the 3-DTI volume. The optimization of the 3-DTI technology for this specific application and the performance of the GIC from laboratory tests is presented.

  15. Apparatus and method for detecting gamma radiation

    DOEpatents

    Sigg, R.A.

    1994-12-13

    A high efficiency radiation detector is disclosed for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data. 4 figures.

  16. New Spherical Gamma-Ray and Neutron Emitting Sources for Testing of Radiation Detection Instruments

    PubMed Central

    Lucas, L.; Pibida, L.

    2009-01-01

    The National Institute of Standards and Technology (NIST) has developed new gamma-ray and neutron emitting sources for testing radiation detection systems. These radioactive sources were developed for testing of detection systems in maritime applications. This required special source characteristics.

  17. Particle detection systems and methods

    DOEpatents

    Morris, Christopher L.; Makela, Mark F.

    2010-05-11

    Techniques, apparatus and systems for detecting particles such as muons and neutrons. In one implementation, a particle detection system employs a plurality of drift cells, which can be for example sealed gas-filled drift tubes, arranged on sides of a volume to be scanned to track incoming and outgoing charged particles, such as cosmic ray-produced muons. The drift cells can include a neutron sensitive medium to enable concurrent counting of neutrons. The system can selectively detect devices or materials, such as iron, lead, gold, uranium, plutonium, and/or tungsten, occupying the volume from multiple scattering of the charged particles passing through the volume and can concurrently detect any unshielded neutron sources occupying the volume from neutrons emitted therefrom. If necessary, the drift cells can be used to also detect gamma rays. The system can be employed to inspect occupied vehicles at border crossings for nuclear threat objects.

  18. Pile-up recovery in gamma-ray detection

    SciTech Connect

    Vencelj, Matjaz; Likar, Andrej; Loeher, Bastian; Miklavec, Mojca; Novak, Roman; Pietralla, Norbert; Savran, Deniz

    2012-07-09

    Count rates in gamma-ray detectors are fundamentally limited at the high end by the physics of the detection process but should not be limited further by the design of read-out. Using intense stimuli, such as the ELI, it is desirable to extract the full wealth of information flow that sensors can deliver. We discuss the photon-statistical limitations of scintillation systems and charge-collection issues of solid-state detectors. With high-speed digitizing in particular, two promising approach architectures are those of posterior list mode corrections and of time-domain adaptive filters, introducing a 'rich list mode with uncertainties' and thus a somewhat different look at experimental spectra. Real-time performance is also considered.

  19. Gamma-ray Albedo of Small Solar System Bodies

    SciTech Connect

    Moskalenko, I.V.

    2008-03-25

    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 KBOs 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). If detected, it can be used to derive the mass spectrum of small bodies in the Main Belt and Kuiper Belt and to probe the spectrum of CR nuclei at close-to-interstellar conditions. The orbits of the Main Belt asteroids and KBOs are distributed near the ecliptic, which passes through the Galactic center and high Galactic latitudes. Therefore, 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. 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. For details of our calculations and references see [1].

  20. Gamma beam system at ELI-NP

    SciTech Connect

    Ur, Calin Alexandru

    2015-02-24

    The Gamma Beam System of ELI-NP will produce brilliant, quasi-monochromatic gamma-ray beams via Inverse Compton Scattering of short laser pulses on relativistic electron beam pulses. The scattered radiation is Doppler upshifted by more than 1,000,000 times and is forward focused in a narrow, polarized, tunable, laser-like beam. The gamma-ray beam at ELI-NP will be characterized by large spectral density of about 10{sup 4} photons/s/eV, narrow bandwidth (< 0.5%) and tunable energy from 200 keV up to about 20 MeV. The Gamma Beam System is a state-of-the-art equipment employing techniques and technologies at the limits of the present-day's knowledge.

  1. Energy- and time-resolved detection of prompt gamma-rays for proton range verification

    NASA Astrophysics Data System (ADS)

    Verburg, Joost M.; Riley, Kent; Bortfeld, Thomas; Seco, Joao

    2013-10-01

    In this work, we present experimental results of a novel prompt gamma-ray detector for proton beam range verification. The detection system features an actively shielded cerium-doped lanthanum(III) bromide scintillator, coupled to a digital data acquisition system. The acquisition was synchronized to the cyclotron radio frequency to separate the prompt gamma-ray signals from the later-arriving neutron-induced background. We designed the detector to provide a high energy resolution and an effective reduction of background events, enabling discrete proton-induced prompt gamma lines to be resolved. Measuring discrete prompt gamma lines has several benefits for range verification. As the discrete energies correspond to specific nuclear transitions, the magnitudes of the different gamma lines have unique correlations with the proton energy and can be directly related to nuclear reaction cross sections. The quantification of discrete gamma lines also enables elemental analysis of tissue in the beam path, providing a better prediction of prompt gamma-ray yields. We present the results of experiments in which a water phantom was irradiated with proton pencil-beams in a clinical proton therapy gantry. A slit collimator was used to collimate the prompt gamma-rays, and measurements were performed at 27 positions along the path of proton beams with ranges of 9, 16 and 23 g cm-2 in water. The magnitudes of discrete gamma lines at 4.44, 5.2 and 6.13 MeV were quantified. The prompt gamma lines were found to be clearly resolved in dimensions of energy and time, and had a reproducible correlation with the proton depth-dose curve. We conclude that the measurement of discrete prompt gamma-rays for in vivo range verification of clinical proton beams is feasible, and plan to further study methods and detector designs for clinical use.

  2. Modeling of Air Attenuation Effects on Gamma Detection at Altitude

    SciTech Connect

    R. S. Detwiler

    2002-10-01

    This paper focuses on modeling the detection capabilities of NaI sensor systems at high altitudes for ground sources. The modeling was done with the Monte Carlo N-Transport (MCNP) code developed at Los Alamos National Laboratory. The specific systems modeled were the fixed wing and helicopter aircraft sensor systems, assets of the U. S. Department of Energy's National Nuclear Security Administration Nevada Operations Office (NNSA/NV) Aerial Measuring System (AMS). In previous (2001) modeling, Sodium Iodine (NaI) detector responses were simulated for both point and distributed surface sources as a function of gamma energy and altitude. For point sources, photo-peak efficiencies were calculated for a zero radial distance and an offset equal to the altitude. For distributed sources approximating an infinite plane, gross count efficiencies were calculated and normalized to a uniform surface deposition of 1 {micro}Ci/m{sup 2}. To validate the calculations, benchmark measurements were made for simple source-detector configurations. The 2002 continuation of the modeling presented here includes checking models against available data, and modifications to allow more effective and accurate directional biasing of ground point and distributed sources. Fixed-wing data results will be shown for two point sources as a function of altitude.

  3. Wavelet Approach for Operational Gamma Spectral Peak Detection - Preliminary Assessment

    SciTech Connect

    ,

    2012-02-01

    Gamma spectroscopy for radionuclide identifications typically involves locating spectral peaks and matching the spectral peaks with known nuclides in the knowledge base or database. Wavelet analysis, due to its ability for fitting localized features, offers the potential for automatic detection of spectral peaks. Past studies of wavelet technologies for gamma spectra analysis essentially focused on direct fitting of raw gamma spectra. Although most of those studies demonstrated the potentials of peak detection using wavelets, they often failed to produce new benefits to operational adaptations for radiological surveys. This work presents a different approach with the operational objective being to detect only the nuclides that do not exist in the environment (anomalous nuclides). With this operational objective, the raw-count spectrum collected by a detector is first converted to a count-rate spectrum and is then followed by background subtraction prior to wavelet analysis. The experimental results suggest that this preprocess is independent of detector type and background radiation, and is capable of improving the peak detection rates using wavelets. This process broadens the doors for a practical adaptation of wavelet technologies for gamma spectral surveying devices.

  4. Enhanced detection of terrestrial gamma-ray flashes by AGILE

    NASA Astrophysics Data System (ADS)

    Marisaldi, M.; Argan, A.; Ursi, A.; Gjesteland, T.; Fuschino, F.; Labanti, C.; Galli, M.; Tavani, M.; Pittori, C.; Verrecchia, F.; D'Amico, F.; Østgaard, N.; Mereghetti, S.; Campana, R.; Cattaneo, P. W.; Bulgarelli, A.; Colafrancesco, S.; Dietrich, S.; Longo, F.; Gianotti, F.; Giommi, P.; Rappoldi, A.; Trifoglio, M.; Trois, A.

    2015-11-01

    At the end of March 2015 the onboard software configuration of the Astrorivelatore Gamma a Immagini Leggero (AGILE) satellite was modified in order to disable the veto signal of the anticoincidence shield for the minicalorimeter instrument. The motivation for such a change was the understanding that the dead time induced by the anticoincidence prevented the detection of a large fraction of Terrestrial Gamma-Ray Flashes (TGFs). The configuration change was highly successful resulting in an increase of one order of magnitude in TGF detection rate. As expected, the largest fraction of the new events has short duration (<100 μs), and part of them has simultaneous association with lightning sferics detected by the World Wide Lightning Location Network. The new configuration provides the largest TGF detection rate surface density (TGFs/km2/yr) to date, opening prospects for improved correlation studies with lightning and atmospheric parameters on short spatial and temporal scales along the equatorial region.

  5. Gamma motes for detection of radioactive materials in shipping containers

    SciTech Connect

    Harold McHugh; William Quam; Stephan Weeks; Brendan Sever

    2007-04-13

    Shipping containers can be effectively monitored for radiological materials using gamma (and neutron) motes in distributed mesh networks. The mote platform is ideal for collecting data for integration into operational management systems required for efficiently and transparently monitoring international trade. Significant reductions in size and power requirements have been achieved for room-temperature cadmium zinc telluride (CZT) gamma detectors. Miniaturization of radio modules and microcontroller units are paving the way for low-power, deeply-embedded, wireless sensor distributed mesh networks.

  6. The Pulsed Interrogation Neutron and Gamma (PING) inspection system

    SciTech Connect

    Schultz, F.J.; Hensley, D.C.; Coffey, D.E.; Chapman, J.A.; Caylor, B.A.; Bailey, R.D. ); Vourvopoulos, G. ); Kehayias, J. . USDA Human Nutrition Research Center on Aging at Tufts Univ.)

    1991-01-01

    Explosives and chemical warfare (CW) agents possess elements and characteristic elemental ratios not commonly found in significant quantities in other items. These elements include nitrogen, oxygen, fluorine, phosphorus, sulfur, and chlorine. The research described herein discusses the results to date of the development of a pulsed-neutron interrogation and gamma ({gamma})-ray system for detecting concealed explosives and for discriminating munitions containing CW agents and conventional explosives. Preliminary experimental data has suggested that distinct classes of chemical agents could also be distinguished, for example, nerve agents and mustard gases. Based on there results, the system is currently being designed for the detection of explosives concealed, for example, in airline luggage. Nuclear and x-ray technologies possess unique characteristics to quickly and reliably search for explosives. Both oxygen and nitrogen, present in sufficient concentrations, when detected, uniquely determine the presence of explosives. Carbon would be a third element that is common in all explosives, although it does not correlate uniquely with all known explosives. A system which identifies and quantifies all three elements would provide more reliable information about the interrogated material. We have previously demonstrated that the technique described in this paper can identify certain elements through fast- and slow-neutron interrogation and subsequent prompt- and delayed-{gamma}-ray detection. The identification of CW agent elements such as chlorine, phosphorus, sulfur, and fluorine, is also accomplished through the detection of characteristic capture {gamma}-rays. The Pulsed Interrogation Neutron and Gamma (PING) inspection system is based upon technology developed over twelve years for the determination of fissile mass quantities in radioactive waste, for the determination of sulfur in coal, and for in-vivo body composition measurements.

  7. The Pulsed Interrogation Neutron and Gamma (PING) inspection system

    SciTech Connect

    Schultz, F.J.; Hensley, D.C.; Coffey, D.E.; Chapman, J.A.; Caylor, B.A.; Bailey, R.D.; Vourvopoulos, G.; Kehayias, J.

    1991-12-31

    Explosives and chemical warfare (CW) agents possess elements and characteristic elemental ratios not commonly found in significant quantities in other items. These elements include nitrogen, oxygen, fluorine, phosphorus, sulfur, and chlorine. The research described herein discusses the results to date of the development of a pulsed-neutron interrogation and gamma ({gamma})-ray system for detecting concealed explosives and for discriminating munitions containing CW agents and conventional explosives. Preliminary experimental data has suggested that distinct classes of chemical agents could also be distinguished, for example, nerve agents and mustard gases. Based on there results, the system is currently being designed for the detection of explosives concealed, for example, in airline luggage. Nuclear and x-ray technologies possess unique characteristics to quickly and reliably search for explosives. Both oxygen and nitrogen, present in sufficient concentrations, when detected, uniquely determine the presence of explosives. Carbon would be a third element that is common in all explosives, although it does not correlate uniquely with all known explosives. A system which identifies and quantifies all three elements would provide more reliable information about the interrogated material. We have previously demonstrated that the technique described in this paper can identify certain elements through fast- and slow-neutron interrogation and subsequent prompt- and delayed-{gamma}-ray detection. The identification of CW agent elements such as chlorine, phosphorus, sulfur, and fluorine, is also accomplished through the detection of characteristic capture {gamma}-rays. The Pulsed Interrogation Neutron and Gamma (PING) inspection system is based upon technology developed over twelve years for the determination of fissile mass quantities in radioactive waste, for the determination of sulfur in coal, and for in-vivo body composition measurements.

  8. Background radiation accumulation and lower limit of detection in thermoluminescent beta-gamma dosimeters used by the centralized external dosimetry system

    SciTech Connect

    Sonder, E.; Ahmed, A.B.

    1991-12-01

    A value for ``average background radiation`` of 0.75 mR/week has been determined from a total of 1680 thermoluminescent dosimeters (TLD`s) exposed in 70 houses for periods up to one year. The distribution of results indicates a rather large variation among houses, with a few locations exhibiting backgrounds double the general average. Some discrepancies in the short-term background accumulation of TLD`s have been explained as being due to light leakage through the dosimeter cases. In addition the lower limit of detection (L{sub D}) for deep and shallow dose equivalents has been determined for these dosimeters. The L{sub D} for occupational exposure depends strongly on the time a dosimeter is exposed to background radiation in the field. The L{sub D} can vary from a low of 2.4 mrem for high energy gamma rays when the background accumulation period is less than a few weeks to values as high as 66 mrem for uranium beta particles when background has been allowed to accumulate for more than 21 weeks.

  9. Method and system for detecting explosives

    DOEpatents

    Reber, Edward L.; Jewell, James K.; Rohde, Kenneth W.; Seabury, Edward H.; Blackwood, Larry G.; Edwards, Andrew J.; Derr, Kurt W.

    2009-03-10

    A method of detecting explosives in a vehicle includes providing a first rack on one side of the vehicle, the rack including a neutron generator and a plurality of gamma ray detectors; providing a second rack on another side of the vehicle, the second rack including a neutron generator and a plurality of gamma ray detectors; providing a control system, remote from the first and second racks, coupled to the neutron generators and gamma ray detectors; using the control system, causing the neutron generators to generate neutrons; and performing gamma ray spectroscopy on spectra read by the gamma ray detectors to look for a signature indicative of presence of an explosive. Various apparatus and other methods are also provided.

  10. Portable modular detection system

    DOEpatents

    Brennan, James S.; Singh, Anup; Throckmorton, Daniel J.; Stamps, James F.

    2009-10-13

    Disclosed herein are portable and modular detection devices and systems for detecting electromagnetic radiation, such as fluorescence, from an analyte which comprises at least one optical element removably attached to at least one alignment rail. Also disclosed are modular detection devices and systems having an integrated lock-in amplifier and spatial filter and assay methods using the portable and modular detection devices.

  11. A Spartan3E-based low-cost system for gamma-ray detection in small single photon emission computed tomography or positron emission tomography systems

    NASA Astrophysics Data System (ADS)

    Fysikopoulos, E.; Georgiou, M.; Efthimiou, N.; David, S.; Loudos, G.; Matsopoulos, G.

    2011-11-01

    The development and assessment of a readout system based on field programmable gate arrays (FPGA) for dedicated nuclear medicine cameras is presented. We have used Xilinx Spartan3E starter kit, which is one of the simplest FPGA evaluation boards. The aim of this work is to offer a simple, open source, data acquisition tool, which provides accurate results for nuclear imaging applications. The system has been evaluated using three different experimental setups: pulses from two position-sensitive photo-multipliers (PSPMTs) and a silicon photo-multiplier (SiPM) were recorded, using 99mTc sources. Two dual channel, external, 12 bit analog to digital converters with a sampling rate of 1 Msps per channel were used. The tool was designed using Xilinx's embedded development kit and was based in Xilinx's Microblaze soft-core processor. A reference multiparameter-based data acquisition system using nuclear instrumentation modules was used for the evaluation of the proposed system. A number of tests were carried out to assess different algorithms for pulse maximum estimation and Gaussian fitting provided optimal results. The results have shown that the FPGA data acquisition system (i) provides accurate digitization of the PSPMT anode signals under various conditions and (ii) gives similar energy spectra when SiPMs are used.

  12. Detection of SNM by delayed gamma rays from induced fission

    NASA Astrophysics Data System (ADS)

    Rennhofer, H.; Crochemore, J.-M.; Roesgen, E.; Pedersen, B.

    2011-10-01

    The Pulsed Neutron Interrogation Test Assembly (PUNITA) is an experimental device for research in NDA methods and field applicable instrumentation for nuclear safeguards and security applications. PUNITA incorporates a standard 14-MeV (D-T) pulsed neutron generator inside a large graphite mantle. The generator target is surrounded by a thick tungsten filter with the purpose to increase the neutron output and to tailor the neutron energy spectrum. In this configuration a sample may be exposed to a relatively high average thermal neutron flux of about (2.2±0.1)×10 3 s -1 cm -2 at only 10% of the maximum target neutron emission. The sample cavity is large enough to allow variation of the experimental setup including the fissile sample, neutron and gamma detectors, and shielding materials. The response from SNM samples of different fissile material content was investigated with various field-applicable scintillation gamma detectors such as the 3×2 in. LaBr 3 detector. Shielding in the form of tungsten and cadmium was applied to the detector to improve the signal to background ratio. Gamma and neutron shields surrounding the samples were also tested for the purpose of simulating clandestine conduct. The energy spectra of delayed gamma rays were recorded in the range 100 keV-9 MeV. In addition time spectra of delayed gamma rays in the range 3.3-8 MeV were recorded in the time period of 10 ms-120 s after the 14-MeV neutron burst. The goal of the experiment was to optimize the sample/detector configuration including the energy range and time period for SNM detection. The results show, for example, that a 170 g sample of depleted uranium can be detected with the given setup in less than 3 min of investigation. Samples of higher enrichment or higher mass are detected in much shorter time.

  13. Uptake of gamma-valerolactone--detection of gamma-hydroxyvaleric acid in human urine samples.

    PubMed

    Andresen-Streichert, H; Jungen, H; Gehl, A; Müller, A; Iwersen-Bergmann, S

    2013-05-01

    Gamma-valerolactone (GVL) is reported to be a substance that can be used as a legal substitute for gamma-hydroxybutyric acid (GHB), which is currently a controlled substance in several countries. Unlike gamma-butyrolactone and 1,4-butanediol, GVL is not metabolized to GHB, which causes the effects after uptake of these two chemicals. In the case of GVL, the lactone ring is split to gamma-hydroxyvaleric acid (GHV or 4-methyl-GHB) by a lactonase. Because of its affinity for the GHB receptor, GHV reveals similar effects to GHB, although it is less potent. Intoxications with GVL, or its use as a date rape drug, are conceivable. Despite these facts, there are no publications in the literature regarding detections of GHV in human samples. This study reports three cases, including five urine samples, in which GHV could be detected in concentrations between 3 and 5.8 mg/L. In one of these cases, a drug-facilitated sexual assault (DFSA) was assumed; four of these samples were from two people suspected of abusing GHB. The results indicate that GVL is used as an alternative to GHB and its precursors and should be taken seriously. GVL or GHV should be included in toxicological analysis, particularly in DFSA cases. More information is needed regarding the pharmacokinetics of GVL/GHV for the meaningful interpretation of positive or negative results. PMID:23486087

  14. A radio-high-performance liquid chromatography dual-flow cell gamma-detection system for on-line radiochemical purity and labeling efficiency determination.

    PubMed

    Lindegren, S; Jensen, H; Jacobsson, L

    2014-04-11

    In this study, a method of determining radiochemical yield and radiochemical purity using radio-HPLC detection employing a dual-flow-cell system is evaluated. The dual-flow cell, consisting of a reference cell and an analytical cell, was constructed from two PEEK capillary coils to fit into the well of a NaI(Tl) detector. The radio-HPLC flow was directed from the injector to the reference cell allowing on-line detection of the total injected sample activity prior to entering the HPLC column. The radioactivity eluted from the column was then detected in the analytical cell. In this way, the sample will act as its own standard, a feature enabling on-line quantification of the processed radioactivity passing through the system. All data were acquired on-line via an analog signal from a rate meter using chromatographic software. The radiochemical yield and recovery could be simply and accurately determined by integration of the peak areas in the chromatogram obtained from the reference and analytical cells using an experimentally determined volume factor to correct for the effect of different cell volumes. PMID:24630054

  15. Recent DMSP satellite detections of gamma-ray bursts

    SciTech Connect

    Terrell, J.; Lee, P.; Klebesadel, R. W.; Griffee, J. W.

    1998-05-16

    Gamma-ray burst detectors are aboard seven U.S. Air Force Defense Meteorological Satellite Program (DMSP) spacecraft, two of which are currently in use. Their 800 km altitude orbits give a field of view to 117 degrees from the zenith. A great many bursts have been detected, usually in coincidence with detections by GRO or other satellites such as PVO or Ulysses. The directions of the sources can be determined with considerable accuracy from such correlated observations, even when neither GRO nor BeppoSAX is involved. Results obtained from the most recently launched satellites (DMSP 13 and DMSP 14) are given in this paper.

  16. Interior intrusion detection systems

    SciTech Connect

    Rodriguez, J.R.; Matter, J.C. ); Dry, B. )

    1991-10-01

    The purpose of this NUREG is to present technical information that should be useful to NRC licensees in designing interior intrusion detection systems. Interior intrusion sensors are discussed according to their primary application: boundary-penetration detection, volumetric detection, and point protection. Information necessary for implementation of an effective interior intrusion detection system is presented, including principles of operation, performance characteristics and guidelines for design, procurement, installation, testing, and maintenance. A glossary of sensor data terms is included. 36 figs., 6 tabs.

  17. Detecting special nuclear materials in containers using high-energy gamma rays emitted by fission products

    DOEpatents

    Norman, Eric B.; Prussin, Stanley G.

    2007-10-02

    A method and a system for detecting the presence of special nuclear materials in a container. The system and its method include irradiating the container with an energetic beam, so as to induce a fission in the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the fission, to produce a detector signal, comparing the detector signal with a threshold value to form a comparison, and detecting the presence of the special nuclear materials using the comparison.

  18. Slide rule for gamma-ray flaw detection

    SciTech Connect

    Borovin, I.V.

    1984-03-01

    This article describes a slide rule which makes it possible to determine the exposure time quickly and with sufficient accuracy when inspecting steel parts using Cs-137 and Ir-192 as radioactive sources and x-ray films of types RT-1, RM-1, RT-5, etc. The slide rule scales were designed on the basis of experimental data regarding absorption of gamma rays in steel. The slide rule is similar in construction to a normal doublesided slide rule with one slide and a cursor. Gamma-ray flow detection is one of the most common methods of identifying defects using radiation. The films of different components shot by different operators using the slide rule for determining exposure time can be simultaneously developed without visually controlling the photographic density.

  19. Gamma-telescopes Fermi/LAT and GAMMA-400 Trigger Systems Event Recognizing Methods Comparison

    NASA Astrophysics Data System (ADS)

    Arkhangelskaja, I. V.; Murchenko, A. E.; Chasovikov, E. N.; Arkhangelskiy, A. I.; Kheymits, M. D.

    Usually instruments for high-energy γ-quanta registration consists of converter (where γ-quanta produced pairs) and calorimeter for particles energy measurements surrounded by anticoincidence shield used to events identification (whether incident particle was charged or neutral). The influence of pair formation by γ-quanta in shield and the backsplash (moved in the opposite direction particles created due high energy γ-rays interact with calorimeter) should be taken into account. It leads to decrease both effective area and registration efficiency at E>10 GeV. In the presented article the event recognizing methods used in Fermi/LAT trigger system is considered in comparison with the ones applied in counting and triggers signals formation system of gamma-telescope GAMMA-400. The GAMMA-400 (Gamma Astronomical Multifunctional Modular Apparatus) will be the new high-apogee space γ-observatory. The GAMMA-400 consist of converter-tracker based on silicon-strip coordinate detectors interleaved with tungsten foils, imaging calorimeter make of 2 layers of double (x, y) silicon strip coordinate detectors interleaved with planes of CsI(Tl) crystals and the electromagnetic calorimeter CC2 consists only of CsI(Tl) crystals. Several plastics detections systems used as anticoincidence shield, for particles energy and moving direction estimations. The main differences of GAMMA-400 constructions from Fermi/LAT one are using the time-of-flight system with base of 50 cm and double layer structure of plastic detectors provides more effective particles direction definition and backsplash rejection. Also two calorimeters in GAMMA-400 composed the total absorbtion spectrometer with total thickness ∼ 25 X0 or ∼1.2 λ0 for vertical incident particles registration and 54 X0 or 2.5 λ0 for laterally incident ones (where λ0 is nuclear interaction length). It provides energy resolution 1-2% for 10 GeV-3.0×103 GeV events while the Fermi/LAT energy resolution does not reach such a

  20. Detection of high-energy gamma rays from winter thunderclouds.

    PubMed

    Tsuchiya, H; Enoto, T; Yamada, S; Yuasa, T; Kawaharada, M; Kitaguchi, T; Kokubun, M; Kato, H; Okano, M; Nakamura, S; Makishima, K

    2007-10-19

    A report is made on a comprehensive observation of a burstlike gamma-ray emission from thunderclouds on the Sea of Japan, during strong thunderstorms on 6 January 2007. The detected emission, lasting for approximately 40 sec, preceded cloud-to-ground lightning discharges. The burst spectrum, extending to 10 MeV, can be interpreted as consisting of bremsstrahlung photons originating from relativistic electrons. This ground-based observation provides the first clear evidence that strong electric fields in thunderclouds can continuously accelerate electrons beyond 10 MeV prior to lightning discharges. PMID:17995261

  1. Radiation anomaly detection algorithms for field-acquired gamma energy spectra

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sanjoy; Maurer, Richard; Wolff, Ron; Guss, Paul; Mitchell, Stephen

    2015-08-01

    The Remote Sensing Laboratory (RSL) is developing a tactical, networked radiation detection system that will be agile, reconfigurable, and capable of rapid threat assessment with high degree of fidelity and certainty. Our design is driven by the needs of users such as law enforcement personnel who must make decisions by evaluating threat signatures in urban settings. The most efficient tool available to identify the nature of the threat object is real-time gamma spectroscopic analysis, as it is fast and has a very low probability of producing false positive alarm conditions. Urban radiological searches are inherently challenged by the rapid and large spatial variation of background gamma radiation, the presence of benign radioactive materials in terms of the normally occurring radioactive materials (NORM), and shielded and/or masked threat sources. Multiple spectral anomaly detection algorithms have been developed by national laboratories and commercial vendors. For example, the Gamma Detector Response and Analysis Software (GADRAS) a one-dimensional deterministic radiation transport software capable of calculating gamma ray spectra using physics-based detector response functions was developed at Sandia National Laboratories. The nuisance-rejection spectral comparison ratio anomaly detection algorithm (or NSCRAD), developed at Pacific Northwest National Laboratory, uses spectral comparison ratios to detect deviation from benign medical and NORM radiation source and can work in spite of strong presence of NORM and or medical sources. RSL has developed its own wavelet-based gamma energy spectral anomaly detection algorithm called WAVRAD. Test results and relative merits of these different algorithms will be discussed and demonstrated.

  2. Range verification of passively scattered proton beams using prompt gamma-ray detection

    NASA Astrophysics Data System (ADS)

    Verburg, Joost M.; Testa, Mauro; Seco, Joao

    2015-02-01

    We performed an experimental study to verify the range of passively scattered proton beams by detecting prompt gamma-rays emitted from proton-nuclear interactions. A method is proposed using a single scintillation detector positioned near the distal end of the irradiated target. Lead shielding was used to attenuate gamma-rays emitted along most of the entrance path of the beam. By synchronizing the prompt gamma-ray detector to the rotation of the range modulation wheel, the relation between the gamma emission from the distal part of the target and the range of the incident proton beam was determined. In experiments with a water phantom and an anthropomorphic head phantom, this relation was found to be sensitive to range shifts that were introduced. The wide opening angle of the detector enabled a sufficient signal-to-background ratio to be achieved in the presence of neutron-induced background from the scattering and collimating devices. Uniform range shifts were detected with a standard deviation of 0.1 mm to 0.2 mm at a dose level of 30 cGy to 50 cGy (RBE). The detectable magnitude of a range shift limited to a part of the treatment field area was approximately proportional to the ratio between the field area and the area affected by the range shift. We conclude that it is feasible to detect changes in the range of passively scattered proton beams using a relatively simple prompt gamma-ray detection system. The method can be employed for in vivo verification of the consistency of the delivered range in fractionated treatments.

  3. Enhanced detection of Terrestrial Gamma-Ray Flashes by AGILE

    NASA Astrophysics Data System (ADS)

    Marisaldi, M.; Argan, A.; Ursi, A.; Gjesteland, T.; Fuschino, F.; Labanti, C.; Galli, M.; Tavani, M.; Pittori, C.; Verrecchia, F.; D'Amico, F.; Ostgaard, N.; Mereghetti, S.; Campana, R.; Cattaneo, P.; Bulgarelli, A.; Colafrancesco, S.; Dietrich, S.; Longo, F.; Gianotti, F.; Giommi, P.; Rappoldi, A.; Trifoglio, M.; Trois, A.

    2015-12-01

    At the end of March 2015 the onboard configuration of the AGILE satellite was modified in order to disable the veto signal of the anticoincidence shield for the minicalorimeter instrument. The motivation for such a change was the understanding that the dead time induced by the anticoincidence prevented the detection of a large fraction of Terrestrial Gamma-ray Flashes (TGFs), especially the short duration ones. We present here the characteristics of the new TGF sample after several months of stable operations with the new configuration. The configuration change was highly successful resulting in the detection of about 100 TGFs/month, an increase of a factor about 11 in TGFs detection rate with respect to previous configuration. As expected, the largest fraction of the new events has short duration, with a median duration of 80 microseconds. We also obtain a sample of events with simultaneous association, within 100 microseconds, with lightning sferics detected by the World Wide Lightning Location Network (WWLLN), confirming previous results reported by the Fermi mission. Given the high detection rate and the AGILE very low (+/-2.5°) orbital inclination, the new configuration provides the largest TGF detection rate surface density (TGFs / km2 / year) to date, opening space for correlation studies with lightning and atmospheric parameters on short spatial and temporal scales along the equatorial region. Eventually, the events with associated simultaneous WWLLN sferics provide a highly reliable sample to probe the long-standing issue of the TGF maximal energy.

  4. Minimum Detectable Activity in gamma spectrometry and its use in low level activity measurements.

    PubMed

    Done, L; Ioan, M-R

    2016-08-01

    In this paper there are described three different algorithms of Minimum Detectable Activity (MDA) calculus, and its use in high resolution gamma spectrometry. In the first part, few introductive theoretical aspects related to the MDA are presented. Further, the theory was applied to real gamma rays spectrometry measurements and the results were compared with the activities reference values. Two different gamma spectrometry systems, both of them using High Purity Germanium (HPGe) detectors, but having different efficiencies, were used. Samples having different geometries and radionuclides content were measured. The measured samples were made by dissolving of some acids containing anthropogenic radionuclides in water, obtaining a density of 1g/cm(3). Choosing this type of matrix was done because of its high homogeneity. PMID:27172893

  5. Recent DMSP satellite detections of gamma-ray bursts

    SciTech Connect

    Terrell, J.; Lee, P.; Klebesadel, R.W.; Griffee, J.W.

    1998-05-01

    Gamma-ray burst detectors are aboard seven U.S. Air Force Defense Meteorological Satellite Program (DMSP) spacecraft, two of which are currently in use. Their 800 km altitude orbits give a field of view to 117 degrees from the zenith. A great many bursts have been detected, usually in coincidence with detections by GRO or other satellites such as PVO or Ulysses. The directions of the sources can be determined with considerable accuracy from such correlated observations, even when neither GRO nor BeppoSAX is involved. Results obtained from the most recently launched satellites (DMSP 13 and DMSP 14) are given in this paper. {copyright} {ital 1998 American Institute of Physics.}

  6. Synchronization system for Gamma-4 electrophysical facility

    NASA Astrophysics Data System (ADS)

    Grishin, A. V.; Nazarenko, S. T.; Kozachek, A. V.; Kalashnikov, D. A.; Glushkov, S. L.; Mironychev, B. P.; Martynov, V. M.; Turutin, V. V.; Kul'dyushov, D. A.; Pavlov, V. S.; Demanov, V. A.; Shikhanova, T. F.; Esaeva, Yu. A.

    2015-01-01

    A synchronization system for the Gamma-4 four-module electrophysical facility has been developed. It has been shown that the synchronization system should provide triggering (with precision not worse than ±3 ns) of the high-voltage gas-filled trigatron-type switches of the facility modules (144 spark gaps with an operating voltage of 1 MV), the pre-pulse switches of the modules (24 spark gaps with an operating voltage of 3 MV) and eight Arkad'ev-Marx generators (40 spark gaps with an operating voltage of 100 kV).

  7. Gamma-resonance Contraband Detection using a high current tandem accelerator

    SciTech Connect

    Milton, B. F.; Beis, J.; Dale, D.; Rogers, J.; Ruegg, R.; Debiak, T.; Kamykowski, E.; Melnychuk, S.; Rathke, J.; Sredniawski, J.

    1999-04-26

    TRIUMF and Northrop Grumman have developed a new system for the detection of concealed explosives and drugs. This Contraband Detection System (CDS) is based on the resonant absorption by {sup 14}N of gammas produced using {sup 13}C(p,{gamma}){sup 14}N. The chosen reaction uses protons at 1.75 MeV and the gammas have an energy of 9.17 MeV. By measuring both the resonant and the non-resonant absorption using detectors with good spatial resolution, and applying standard tomographic techniques, we are able to produce 3D images of both the nitrogen partial density and the total density. The images together may be utilized with considerable confidence to determine if small amounts of nitrogen based explosives, heroin or cocaine are present in the interrogated containers. Practical Gamma Resonant Absorption (GRA) scanning requires an intense source of protons. However this proton source must also be very stable, have low energy spread, and have good spatial definition. These demands suggested a tandem as the accelerator of choice. We have therefore constructed a 2 MeV H{sup -} tandem optimized for high current (10 mA) operation, while minimizing the overall size of the accelerator. This has required several special innovations which will be presented in the paper. We will also present initial commissioning results.

  8. Detection of gamma-ray bursts from Andromeda

    SciTech Connect

    Bulik, Tomasz; Coppi, Paolo S.; Lamb, Donald Q.

    1996-08-01

    If gamma-ray bursts originate in a corona around the Milky Way, it should also be possible to detect them from a similar corona around Andromeda. Adopting a simple model of high velocity neutron star corona, we evaluate the ability of instruments on existing missions to detect an excess of bursts toward Andromeda. We also calculate the optimal properties of an instrument designed to detect such an excess. We find that if the bursts radiate isotropically, an experiment with a sampling distance d{sub max} > or approx. 500 kpc could detect a significant excess of bursts in the direction of Andromeda in a few years of observation. If the radiation is beamed along the neutron star's direction of motion, an experiment with d{sub max} > or approx. 800 kpc would detect such an excess in a similar amount of time, provided that the width of the beam is greater than 10 deg. Lack of an excess toward Andromeda would therefore be compelling evidence that the bursts are cosmological in origin if made by an instrument at least 50 times more sensitive than BATSE, given current constraints on Galactic corona models. Comparisons with detailed dynamical calculations of the spatial distribution of high velocity neutron stars in the coronae around the Milky Way and Andromeda confirm these conclusions.

  9. Idaho Explosive Detection System

    SciTech Connect

    Klinger, Jeff

    2011-01-01

    Learn how INL researchers are making the world safer by developing an explosives detection system that can inspect cargo. For more information about INL security research, visit http://www.facebook.com/idahonationallaboratory

  10. Idaho Explosive Detection System

    ScienceCinema

    Klinger, Jeff

    2013-05-28

    Learn how INL researchers are making the world safer by developing an explosives detection system that can inspect cargo. For more information about INL security research, visit http://www.facebook.com/idahonationallaboratory

  11. Underwater laser detection system

    NASA Astrophysics Data System (ADS)

    Gomaa, Walid; El-Sherif, Ashraf F.; El-Sharkawy, Yasser H.

    2015-02-01

    The conventional method used to detect an underwater target is by sending and receiving some form of acoustic energy. But the acoustic systems have limitations in the range resolution and accuracy; while, the potential benefits of a laserbased underwater target detection include high directionality, high response, and high range accuracy. Lasers operating in the blue-green region of the light spectrum(420 : 570nm)have a several applications in the area of detection and ranging of submersible targets due to minimum attenuation through water ( less than 0.1 m-1) and maximum laser reflection from estimated target (like mines or submarines) to provide a long range of detection. In this paper laser attenuation in water was measured experimentally by new simple method by using high resolution spectrometer. The laser echoes from different targets (metal, plastic, wood, and rubber) were detected using high resolution CCD camera; the position of detection camera was optimized to provide a high reflection laser from target and low backscattering noise from the water medium, digital image processing techniques were applied to detect and discriminate the echoes from the metal target and subtract the echoes from other objects. Extraction the image of target from the scattering noise is done by background subtraction and edge detection techniques. As a conclusion, we present a high response laser imaging system to detect and discriminate small size, like-mine underwater targets.

  12. Detection and Location of Gamma-Ray Sources with a Modulating Coded Mask

    SciTech Connect

    Anderson, Dale N.; Stromswold, David C.; Wunschel, Sharon C.; Peurrung, Anthony J.; Hansen, Randy R.

    2006-01-31

    This paper presents methods of detecting and locating a concelaed nuclear gamma-ray source with a coded aperture mask. Energetic gamma rays readily penetrate moderate amounts of shielding material and can be detected at distances of many meters. The detection of high energy gamma-ray sources is vitally important to national security for several reasons, including nuclear materials smuggling interdiction, monitoring weapon components under treaties, and locating nuclear weapons and materials in the possession terrorist organizations.

  13. Bro Intrusion Detection System

    SciTech Connect

    Paxson, Vern; Campbell, Scott; leres, Craig; Lee, Jason

    2006-01-25

    Bro is a Unix-based Network Intrusion Detection System (IDS). Bro monitors network traffic and detects intrusion attempts based on the traffic characteristics and content. Bro detects intrusions by comparing network traffic against rules describing events that are deemed troublesome. These rules might describe activities (e.g., certain hosts connecting to certain services), what activities are worth alerting (e.g., attempts to a given number of different hosts constitutes a "scan"), or signatures describing known attacks or access to known vulnerabilities. If Bro detects something of interest, it can be instructed to either issue a log entry or initiate the execution of an operating system command. Bro targets high-speed (Gbps), high-volume intrusion detection. By judiciously leveraging packet filtering techniques, Bro is able to achieve the performance necessary to do so while running on commercially available PC hardware, and thus can serve as a cost effective means of monitoring a site’s Internet connection.

  14. Shuttle flight test of an advanced gamma-ray detection system. Semi-annual technical report, 1 July-31 December 1983

    SciTech Connect

    Rester, A.C.

    1984-02-28

    In August of 1983 the Gamma-Ray Advanced Detector (GRAD) Project was assigned to the AFP-675 Program for flight on a future space-shuttle mission. In order to adapt the experiment to the requirements of AFP-675, a number of changes were made both in hardware and software. However, the necessity for such changes is more than affected by an expansion in scope of the experiment made possible by the introduction of a Payload Specialist into the operation. The principal changes to be made are in the avionics, as GRAD was originally designed for operation through ground-based telemetry. This complete redesigning of our avionics to accomodate operation by a Payload Specialist from the aft flight deck of the Orbiter allows us to take advantage of very recent findings on radiation-induced microprocessor failure in other space shuttle experiments in order to make the GRAD avionics less vulnerable to such latch-ups. Advances in bismuth germanate (BGO) scintillator technology during the year since construction of the prototype GRAD now make it possible to construct a BGO shield with a closed-ended geometry. This improvement will enhance the signal-to-noise ratio. In addition, a new type of decay-vetoed calibration probe using an alpha-rather than a beta-emitting radioactive source is being investigated.

  15. Portable pathogen detection system

    DOEpatents

    Colston, Billy W.; Everett, Matthew; Milanovich, Fred P.; Brown, Steve B.; Vendateswaran, Kodumudi; Simon, Jonathan N.

    2005-06-14

    A portable pathogen detection system that accomplishes on-site multiplex detection of targets in biological samples. The system includes: microbead specific reagents, incubation/mixing chambers, a disposable microbead capture substrate, and an optical measurement and decoding arrangement. The basis of this system is a highly flexible Liquid Array that utilizes optically encoded microbeads as the templates for biological assays. Target biological samples are optically labeled and captured on the microbeads, which are in turn captured on an ordered array or disordered array disposable capture substrate and then optically read.

  16. Solar system fault detection

    DOEpatents

    Farrington, R.B.; Pruett, J.C. Jr.

    1984-05-14

    A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

  17. Solar system fault detection

    DOEpatents

    Farrington, Robert B.; Pruett, Jr., James C.

    1986-01-01

    A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

  18. Shaped scintillation detector systems for measurements of gamma ray flux anisotropy

    NASA Technical Reports Server (NTRS)

    Trombka, J. I.; Vette, J. I.; Stecker, F. W.; Eller, E. L.; Wildes, W. T.

    1973-01-01

    The detection efficiencies of cylindrical detectors for various gamma ray photon angular distributions were studied in the energy range from .10 Mev to 15 Mev. These studies indicate that simple detector systems on small satellites can be used to measure flux anisotropy of cosmic gamma rays and the angular distribution of albedo gamma rays produced in planetary atmospheres. The results indicate that flat cylindrical detectors are most suitable for measuring flux anisotropy because of their angular response function. A general method for calculating detection efficiencies for such detectors is presented.

  19. Idaho Explosives Detection System

    SciTech Connect

    Edward L. Reber; Larry G. Blackwood; Andrew J. Edwards; J. Keith Jewell; Kenneth W. Rohde; Edward H. Seabury; Jeffery B. Klinger

    2005-12-01

    The Idaho Explosives Detection System was developed at the Idaho National Laboratory (INL) to respond to threats imposed by delivery trucks potentially carrying explosives into military bases. A full-scale prototype system has been built and is currently undergoing testing. The system consists of two racks, one on each side of a subject vehicle. Each rack includes a neutron generator and an array of NaI detectors. The two neutron generators are pulsed and synchronized. A laptop computer controls the entire system. The control software is easily operable by minimally trained staff. The system was developed to detect explosives in a medium size truck within a 5-min measurement time. System performance was successfully demonstrated with explosives at the INL in June 2004 and at Andrews Air Force Base in July 2004.

  20. Method and System for Gamma-Ray Localization Induced Spacecraft Navigation Using Celestial Gamma-Ray Sources

    NASA Technical Reports Server (NTRS)

    Sheikh, Suneel I. (Inventor); Hisamoto, Chuck (Inventor); Arzoumanian, Zaven (Inventor)

    2015-01-01

    A method and system for spacecraft navigation using distant celestial gamma-ray bursts which offer detectable, bright, high-energy events that provide well-defined characteristics conducive to accurate time-alignment among spatially separated spacecraft. Utilizing assemblages of photons from distant gamma-ray bursts, relative range between two spacecraft can be accurately computed along the direction to each burst's source based upon the difference in arrival time of the burst emission at each spacecraft's location. Correlation methods used to time-align the high-energy burst profiles are provided. The spacecraft navigation may be carried out autonomously or in a central control mode of operation.

  1. Gamma-quanta onboard identification in the GAMMA-400 experiment using the counting and triggers signals formation system.

    NASA Astrophysics Data System (ADS)

    Arkhangelskaja, I. V.; Arkhangelskiy, A. I.; Chasovikov, E. N.; Galper, A. M.; Kheymits, M. D.; Murchenko, A. E.; Yurkin, Y. T.

    2016-02-01

    GAMMA-400 (Gamma Astronomical Multifunctional Modular Apparatus) will be the new generation satellite gamma-observatory. Gamma-telescope GAMMA-400 consists of anticoincidence system (top and lateral sections - ACtop and AClat), the converter-tracker (C), time-of-flight system (2 sections S1 and S2), position-sensitive calorimeter CC1 makes of 2 strips layers and 2 layers of CsI(Tl) detectors, electromagnetic calorimeter CC2 composed of CsI(Tl) crystals, neutron detector ND, scintillation detectors of the calorimeter (S3 and S4) and lateral detectors of the calorimeter (LD). All detector systems ACtop, AClat, S1-S4, LD consist of two BC-408 based sensitive layers of 1 cm thickness each. Three apertures provide events registration both from upper and lateral directions. The main aperture provides the best angular (all strip layers information analysis) and energy (energy deposition in the all detectors studying) resolution. Gamma-telescope GAMMA-400 is optimized for the gamma-quanta and charged particles with energy 100 GeV detection with the best parameters in the main aperture. Triggers in the main aperture will be formed using information about particle direction provided by time of flight system and presence of charged particle or backsplash signal formed according to analysis of energy deposition in combination of both layers anticoincidence systems ACtop and AClat individual detectors. For double-layer ACtop taking into account both amplitude and temporal trigger marker onboard analysis only 2.8% photons will be wrongly recognized as electrons or protons for 100 GeV particles. The part of charged particles mistakenly identified as gammas is ∼10-5 using described algorithms. For E∼3 GeV less than 3% photons will be wrongly recognized as charged particles and fraction of wrongly identified charged particles will be also ∼10-5. In the additional aperture the particles identification is provided by analysis of signals corresponding to energy deposition in the

  2. Network of wireless gamma ray sensors for radiological detection and identification

    NASA Astrophysics Data System (ADS)

    Barzilov, A.; Womble, P.; Novikov, I.; Paschal, J.; Board, J.; Moss, K.

    2007-04-01

    The paper describes the design and development of a network of wireless gamma-ray sensors based on cell phone or WiFi technology. The system is intended for gamma-ray detection and automatic identification of radioactive isotopes and nuclear materials. The sensor is a gamma-ray spectrometer that uses wireless technology to distribute the results. A small-size sensor module contains a scintillation detector along with a small size data acquisition system, PDA, battery, and WiFi radio or a cell phone modem. The PDA with data acquisition and analysis software analyzes the accumulated spectrum on real-time basis and returns results to the screen reporting the isotopic composition and intensity of detected radiation source. The system has been programmed to mitigate false alarms from medical isotopes and naturally occurring radioactive materials. The decision-making software can be "trained" to indicate specific signatures of radiation sources like special nuclear materials. The sensor is supplied with GPS tracker coupling radiological information with geographical coordinates. The sensor is designed for easy use and rapid deployment in common wireless networks.

  3. Water system virus detection

    NASA Technical Reports Server (NTRS)

    Fraser, A. S.; Wells, A. F.; Tenoso, H. J.

    1975-01-01

    A monitoring system developed to test the capability of a water recovery system to reject the passage of viruses into the recovered water is described. A nonpathogenic marker virus, bacteriophage F2, is fed into the process stream before the recovery unit and the reclaimed water is assayed for its presence. Detection of the marker virus consists of two major components, concentration and isolation of the marker virus, and detection of the marker virus. The concentration system involves adsorption of virus to cellulose acetate filters in the presence of trivalent cations and low pH with subsequent desorption of the virus using volumes of high pH buffer. The detection of the virus is performed by a passive immune agglutination test utilizing specially prepared polystyrene particles. An engineering preliminary design was performed as a parallel effort to the laboratory development of the marker virus test system. Engineering schematics and drawings of a fully functional laboratory prototype capable of zero-G operation are presented. The instrument consists of reagent pump/metering system, reagent storage containers, a filter concentrator, an incubation/detector system, and an electronic readout and control system.

  4. PET imaging using gamma camera systems: a review.

    PubMed

    Jarritt, P H; Acton, P D

    1996-09-01

    Optimized positron emission tomographs have begun to demonstrate an ever widening range of clinical applications for positron labelled pharmaceuticals. This potential has led to a renewed interest in the use of the more widely available Anger gamma camera detectors for imaging the 511 keV photons from the positron decay process. Two forms of detection can be considered: either the detection of the 511 keV photons as single events or the detection of coincidence events from the opposed pair annihilation photons. The widespread availability of dual, opposed-pair, large field-of-view detectors has promoted the development of coincidence detection without collimation. With detector rotation, positron emission tomography (PET) can be performed. An alternative and lower cost option has been the universal development of ultra high-energy collimators to perform single photon emission tomography (SPET) with 511 keV photons. This review outlines the currently available performance characteristics of these two approaches and compares them with those from two- and three-dimensional PET optimized systems. The limitations on the development of these systems is discussed through the analysis of the principles underlying both single photon and coincidence detection. Preliminary clinical experience indicates that limitations in the performance characteristics of these systems has implications for their potential role, although applications in cardiology and oncology are being pursued. PMID:8895903

  5. The gamma-quantum registration system of SVD setup

    NASA Astrophysics Data System (ADS)

    Golovnya, S.

    2014-09-01

    The gamma-quantum registration system is the part of the SVD setup at the U-70 accelerator (IHEP) exposed in experiments: SERP E-184 (An experiment for studying mechanisms of charmed particle production and decays in pA-interactions at 70 GeV/c) and SERP E-190 (production of particles in pp-interactions in high multiplicity events at 50 GeV/c). The system consists of two detectors — the hodoscope detector of 1532 (48 × 32) cherenkov full absorption counters with a lead glass absorber (DEGA) and the soft photons calorimeter of 49 (7 × 7) counters with BGO crystals (SPC). The following subsystems are described: the high-voltage power system, the DEGA platform positioning control system for detector calibration in an electron beam, the DEGA LED monitoring system. The description of the soft photons calorimeter is also provided. This subsystem is focused to detecting the gamma quantum in energy range of tens MeV. The test results of SPC, obtained during its first operation in the accelerator run of 2013 year, are presented, the energy spectrum of photons are given.

  6. Bro Intrusion Detection System

    Energy Science and Technology Software Center (ESTSC)

    2006-01-25

    Bro is a Unix-based Network Intrusion Detection System (IDS). Bro monitors network traffic and detects intrusion attempts based on the traffic characteristics and content. Bro detects intrusions by comparing network traffic against rules describing events that are deemed troublesome. These rules might describe activities (e.g., certain hosts connecting to certain services), what activities are worth alerting (e.g., attempts to a given number of different hosts constitutes a "scan"), or signatures describing known attacks or accessmore » to known vulnerabilities. If Bro detects something of interest, it can be instructed to either issue a log entry or initiate the execution of an operating system command. Bro targets high-speed (Gbps), high-volume intrusion detection. By judiciously leveraging packet filtering techniques, Bro is able to achieve the performance necessary to do so while running on commercially available PC hardware, and thus can serve as a cost effective means of monitoring a site’s Internet connection.« less

  7. Radiation detection system

    DOEpatents

    Nelson, Melvin A.; Davies, Terence J.; Morton, III, John R.

    1976-01-01

    A radiation detection system which utilizes the generation of Cerenkov light in and the transmission of that light longitudinally through fiber optic wave guides in order to transmit intelligence relating to the radiation to a remote location. The wave guides are aligned with respect to charged particle radiation so that the Cerenkov light, which is generated at an angle to the radiation, is accepted by the fiber for transmission therethrough. The Cerenkov radiation is detected, recorded, and analyzed at the other end of the fiber.

  8. Intercomparison of gamma scattering, gammatography, and radiography techniques for mild steel nonuniform corrosion detection.

    PubMed

    Priyada, P; Margret, M; Ramar, R; Shivaramu; Menaka, M; Thilagam, L; Venkataraman, B; Raj, Baldev

    2011-03-01

    This paper focuses on the mild steel (MS) corrosion detection and intercomparison of results obtained by gamma scattering, gammatography, and radiography techniques. The gamma scattering non-destructive evaluation (NDE) method utilizes scattered gamma radiation for the detection of corrosion, and the scattering experimental setup is an indigenously designed automated personal computer (PC) controlled scanning system consisting of computerized numerical control (CNC) controlled six-axis source detector system and four-axis job positioning system. The system has been successfully used to quantify the magnitude of corrosion and the thickness profile of a MS plate with nonuniform corrosion, and the results are correlated with those obtained from the conventional gammatography and radiography imaging measurements. A simple and straightforward reconstruction algorithm to reconstruct the densities of the objects under investigation and an unambiguous interpretation of the signal as a function of material density at any point of the thick object being inspected is described. In this simple and straightforward method the density of the target need not be known and only the knowledge of the target material's mass attenuation coefficients (composition) for the incident and scattered energies is enough to reconstruct the density of the each voxel of the specimen being studied. The Monte Carlo (MC) numerical simulation of the phenomena is done using the Monte Carlo N-Particle Transport Code (MCNP) and the quantitative estimates of the values of signal-to-noise ratio for different percentages of MS corrosion derived from these simulations are presented and the spectra are compared with the experimental data. The gammatography experiments are carried out using the same PC controlled scanning system in a narrow beam, good geometry setup, and the thickness loss is estimated from the measured transmitted intensity. Radiography of the MS plates is carried out using 160 kV x

  9. Intercomparison of gamma scattering, gammatography and radiography techniques for mild steel nonuniform corrosion detection

    SciTech Connect

    Priyada, P.; Margret, M.; Ramar, R. ); Menaka, M. ); Thilagam, L. ); Venkataraman, B.; Quality Assurance Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603 102, Tamil Nadu ); Baldev Raj )

    2011-03-01

    This paper focuses on the mild steel (MS) corrosion detection and intercomparison of results obtained by gamma scattering, gammatography, and radiography techniques. The gamma scattering non-destructive evaluation (NDE) method utilizes scattered gamma radiation for the detection of corrosion, and the scattering experimental setup is an indigenously designed automated personal computer (PC) controlled scanning system consisting of computerized numerical control (CNC) controlled six-axis source detector system and four-axis job positioning system. The system has been successfully used to quantify the magnitude of corrosion and the thickness profile of a MS plate with nonuniform corrosion, and the results are correlated with those obtained from the conventional gammatography and radiography imaging measurements. A simple and straightforward reconstruction algorithm to reconstruct the densities of the objects under investigation and an unambiguous interpretation of the signal as a function of material density at any point of the thick object being inspected is described. In this simple and straightforward method the density of the target need not be known and only the knowledge of the target material's mass attenuation coefficients (composition) for the incident and scattered energies is enough to reconstruct the density of the each voxel of the specimen being studied. The Monte Carlo (MC) numerical simulation of the phenomena is done using the Monte Carlo N-Particle Transport Code (MCNP) and the quantitative estimates of the values of signal-to-noise ratio for different percentages of MS corrosion derived from these simulations are presented and the spectra are compared with the experimental data. The gammatography experiments are carried out using the same PC controlled scanning system in a narrow beam, good geometry setup, and the thickness loss is estimated from the measured transmitted intensity. Radiography of the MS plates is carried out using 160 kV x

  10. Intercomparison of gamma scattering, gammatography, and radiography techniques for mild steel nonuniform corrosion detection

    NASA Astrophysics Data System (ADS)

    Priyada, P.; Margret, M.; Ramar, R.; Shivaramu, Menaka, M.; Thilagam, L.; Venkataraman, B.; Raj, Baldev

    2011-03-01

    This paper focuses on the mild steel (MS) corrosion detection and intercomparison of results obtained by gamma scattering, gammatography, and radiography techniques. The gamma scattering non-destructive evaluation (NDE) method utilizes scattered gamma radiation for the detection of corrosion, and the scattering experimental setup is an indigenously designed automated personal computer (PC) controlled scanning system consisting of computerized numerical control (CNC) controlled six-axis source detector system and four-axis job positioning system. The system has been successfully used to quantify the magnitude of corrosion and the thickness profile of a MS plate with nonuniform corrosion, and the results are correlated with those obtained from the conventional gammatography and radiography imaging measurements. A simple and straightforward reconstruction algorithm to reconstruct the densities of the objects under investigation and an unambiguous interpretation of the signal as a function of material density at any point of the thick object being inspected is described. In this simple and straightforward method the density of the target need not be known and only the knowledge of the target material's mass attenuation coefficients (composition) for the incident and scattered energies is enough to reconstruct the density of the each voxel of the specimen being studied. The Monte Carlo (MC) numerical simulation of the phenomena is done using the Monte Carlo N-Particle Transport Code (MCNP) and the quantitative estimates of the values of signal-to-noise ratio for different percentages of MS corrosion derived from these simulations are presented and the spectra are compared with the experimental data. The gammatography experiments are carried out using the same PC controlled scanning system in a narrow beam, good geometry setup, and the thickness loss is estimated from the measured transmitted intensity. Radiography of the MS plates is carried out using 160 kV x

  11. Validation of gamma-ray detection techniques for safeguards monitoring at natural uranium conversion facilities

    DOE PAGESBeta

    Dewji, Shaheen A.; Lee, Denise L.; Croft, Stephen; Hertel, Nolan E.; Chapman, Jeffrey Allen; McElroy, Jr., Robert Dennis; Cleveland, S.

    2016-03-28

    Recent IAEA circulars and policy papers have sought to implement safeguards when any purified aqueous uranium solution or uranium oxides suitable for isotopic enrichment or fuel fabrication exists. Under the revised policy, IAEA Policy Paper 18, the starting point for nuclear material under safeguards was reinterpreted, suggesting that purified uranium compounds should be subject to safeguards procedures no later than the first point in the conversion process. In response to this technical need, a combination of simulation models and experimental measurements were employed to develop and validate concepts of nondestructive assay monitoring systems in a natural uranium conversion plant (NUCP).more » In particular, uranyl nitrate (UO2(NO3)2) solution exiting solvent extraction was identified as a key measurement point (KMP), where gamma-ray spectroscopy was selected as the process monitoring tool. The Uranyl Nitrate Calibration Loop Equipment (UNCLE) facility at Oak Ridge National Laboratory was employed to simulate the full-scale operating conditions of a purified uranium-bearing aqueous stream exiting the solvent extraction process in an NUCP. Nondestructive assay techniques using gamma-ray spectroscopy were evaluated to determine their viability as a technical means for drawing safeguards conclusions at NUCPs, and if the IAEA detection requirements of 1 significant quantity (SQ) can be met in a timely way. This work investigated gamma-ray signatures of uranyl nitrate circulating in the UNCLE facility and evaluated various gamma-ray detector sensitivities to uranyl nitrate. These detector validation activities include assessing detector responses to the uranyl nitrate gamma-ray signatures for spectrometers based on sodium iodide, lanthanum bromide, and high-purity germanium detectors. The results of measurements under static and dynamic operating conditions at concentrations ranging from 10–90 g U/L of natural uranyl nitrate are presented. A range of gamma

  12. Validation of gamma-ray detection techniques for safeguards monitoring at natural uranium conversion facilities

    NASA Astrophysics Data System (ADS)

    Dewji, S. A.; Lee, D. L.; Croft, S.; Hertel, N. E.; Chapman, J. A.; McElroy, R. D.; Cleveland, S.

    2016-07-01

    Recent IAEA circulars and policy papers have sought to implement safeguards when any purified aqueous uranium solution or uranium oxides suitable for isotopic enrichment or fuel fabrication exists. Under the revised policy, IAEA Policy Paper 18, the starting point for nuclear material under safeguards was reinterpreted, suggesting that purified uranium compounds should be subject to safeguards procedures no later than the first point in the conversion process. In response to this technical need, a combination of simulation models and experimental measurements were employed to develop and validate concepts of nondestructive assay monitoring systems in a natural uranium conversion plant (NUCP). In particular, uranyl nitrate (UO2(NO3)2) solution exiting solvent extraction was identified as a key measurement point (KMP), where gamma-ray spectroscopy was selected as the process monitoring tool. The Uranyl Nitrate Calibration Loop Equipment (UNCLE) facility at Oak Ridge National Laboratory was employed to simulate the full-scale operating conditions of a purified uranium-bearing aqueous stream exiting the solvent extraction process in an NUCP. Nondestructive assay techniques using gamma-ray spectroscopy were evaluated to determine their viability as a technical means for drawing safeguards conclusions at NUCPs, and if the IAEA detection requirements of 1 significant quantity (SQ) can be met in a timely way. This work investigated gamma-ray signatures of uranyl nitrate circulating in the UNCLE facility and evaluated various gamma-ray detector sensitivities to uranyl nitrate. These detector validation activities include assessing detector responses to the uranyl nitrate gamma-ray signatures for spectrometers based on sodium iodide, lanthanum bromide, and high-purity germanium detectors. The results of measurements under static and dynamic operating conditions at concentrations ranging from 10-90 g U/L of natural uranyl nitrate are presented. A range of gamma-ray lines is

  13. Fast-neutron/gamma-ray radiography scanner for the detection of contraband in air cargo containers

    NASA Astrophysics Data System (ADS)

    Eberhardt, J.; Liu, Y.; Rainey, S.; Roach, G.; Sowerby, B.; Stevens, R.; Tickner, J.

    2006-05-01

    There is a worldwide need for efficient inspection of cargo containers at airports, seaports and road border crossings. The main objectives are the detection of contraband such as illicit drugs, explosives and weapons. Due to the large volume of cargo passing through Australia's airports every day, it is critical that any scanning system should be capable of working on unpacked or consolidated cargo, taking at most 1-2 minutes per container. CSIRO has developed a fast-neutron/gamma-ray radiography (FNGR) method for the rapid screening of air freight. By combining radiographs obtained using 14 MeV neutrons and 60Co gamma-rays, high resolution images showing both density and material composition are obtained. A near full-scale prototype scanner has been successfully tested in the laboratory. With the support of the Australian Customs Service, a full-scale scanner has recently been installed and commissioned at Brisbane International Airport.

  14. Advanced Laser-Compton Gamma-Ray Sources for Nuclear Materials Detection, Assay and Imaging

    NASA Astrophysics Data System (ADS)

    Barty, C. P. J.

    2015-10-01

    Highly-collimated, polarized, mono-energetic beams of tunable gamma-rays may be created via the optimized Compton scattering of pulsed lasers off of ultra-bright, relativistic electron beams. Above 2 MeV, the peak brilliance of such sources can exceed that of the world's largest synchrotrons by more than 15 orders of magnitude and can enable for the first time the efficient pursuit of nuclear science and applications with photon beams, i.e. Nuclear Photonics. Potential applications are numerous and include isotope-specific nuclear materials management, element-specific medical radiography and radiology, non-destructive, isotope-specific, material assay and imaging, precision spectroscopy of nuclear resonances and photon-induced fission. This review covers activities at the Lawrence Livermore National Laboratory related to the design and optimization of mono-energetic, laser-Compton gamma-ray systems and introduces isotope-specific nuclear materials detection and assay applications enabled by them.

  15. AGILE DETECTION OF DELAYED GAMMA-RAY EMISSION FROM THE SHORT GAMMA-RAY BURST GRB 090510

    SciTech Connect

    Giuliani, A.; Vianello, G.; Mereghetti, S.; Caraveo, P.; Chen, A. W.; Contessi, T.; Barbiellini, G.; Longo, F.; Moretti, E.; Cattaneo, P. W.

    2010-01-10

    Short gamma-ray bursts (GRBs), typically lasting less than 2 s, are a special class of GRBs of great interest. We report the detection by the AGILE satellite of the short GRB 090510 which shows two clearly distinct emission phases: a prompt phase lasting {approx}200 ms and a second phase lasting tens of seconds. The prompt phase is relatively intense in the 0.3-10 MeV range with a spectrum characterized by a large peak/cutoff energy near 3 MeV; in this phase, no significant high-energy gamma-ray emission is detected. At the end of the prompt phase, intense gamma-ray emission above 30 MeV is detected showing a power-law time decay of the flux of the type t {sup -1.3} and a broadband spectrum remarkably different from that of the prompt phase. It extends from sub-MeV to hundreds of MeV energies with a photon index {alpha} {approx_equal} 1.5. GRB 090510 provides the first case of a short GRB with delayed gamma-ray emission. We present the timing and spectral data of GRB 090510 and briefly discuss its remarkable properties within the current models of gamma-ray emission of short GRBs.

  16. Electrochemical impedance spectroscopy based-on interferon-gamma detection

    NASA Astrophysics Data System (ADS)

    Li, Guan-Wei; Kuo, Yi-Ching; Tsai, Pei-I.; Lee, Chih-Kung

    2014-03-01

    Tuberculosis (TB) is an ancient disease constituted a long-term menace to public health. According to World Health Organization (WHO), mycobacterium tuberculosis (MTB) infected nearly a third of people of the world. There is about one new TB occurrence every second. Interferon-gamma (IFN-γ) is associated with susceptibility to TB, and interferongamma release assays (IGRA) is considered to be the best alternative of tuberculin skin test (TST) for diagnosis of latent tuberculosis infection (LTBI). Although significant progress has been made with regard to the design of enzyme immunoassays for IFN-γ, adopting this assay is still labor-intensive and time-consuming. To alleviate these drawbacks, we used IFN-γ antibody to facilitate the detection of IFN-γ. An experimental verification on the performance of IGRA was done in this research. We developed two biosensor configurations, both of which possess high sensitivity, specificity, and rapid IFN-γ diagnoses. The first is the electrochemical method. The second is a circular polarization interferometry configuration, which incorporates two light beams with p-polarization and s-polarization states individually along a common path, a four photo-detector quadrature configuration to arrive at a phase modulated ellipsometer. With these two methods, interaction between IFN-γ antibody and IFN-γ were explored and presented in detail.

  17. Ultrasonic Leak Detection System

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C. (Inventor); Moerk, J. Steven (Inventor)

    1998-01-01

    A system for detecting ultrasonic vibrations. such as those generated by a small leak in a pressurized container. vessel. pipe. or the like. comprises an ultrasonic transducer assembly and a processing circuit for converting transducer signals into an audio frequency range signal. The audio frequency range signal can be used to drive a pair of headphones worn by an operator. A diode rectifier based mixing circuit provides a simple, inexpensive way to mix the transducer signal with a square wave signal generated by an oscillator, and thereby generate the audio frequency signal. The sensitivity of the system is greatly increased through proper selection and matching of the system components. and the use of noise rejection filters and elements. In addition, a parabolic collecting horn is preferably employed which is mounted on the transducer assembly housing. The collecting horn increases sensitivity of the system by amplifying the received signals. and provides directionality which facilitates easier location of an ultrasonic vibration source.

  18. Water system virus detection

    NASA Technical Reports Server (NTRS)

    Fraser, A. S.; Wells, A. F.; Tenoso, H. J. (Inventor)

    1978-01-01

    The performance of a waste water reclamation system is monitored by introducing a non-pathogenic marker virus, bacteriophage F2, into the waste-water prior to treatment and, thereafter, testing the reclaimed water for the presence of the marker virus. A test sample is first concentrated by absorbing any marker virus onto a cellulose acetate filter in the presence of a trivalent cation at low pH and then flushing the filter with a limited quantity of a glycine buffer solution to desorb any marker virus present on the filter. Photo-optical detection of indirect passive immune agglutination by polystyrene beads indicates the performance of the water reclamation system in removing the marker virus. A closed system provides for concentrating any marker virus, initiating and monitoring the passive immune agglutination reaction, and then flushing the system to prepare for another sample.

  19. A comprehensive overview of radioguided surgery using gamma detection probe technology

    PubMed Central

    Povoski, Stephen P; Neff, Ryan L; Mojzisik, Cathy M; O'Malley, David M; Hinkle, George H; Hall, Nathan C; Murrey, Douglas A; Knopp, Michael V; Martin, Edward W

    2009-01-01

    The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology. PMID:19173715

  20. Gas Flow Detection System

    NASA Technical Reports Server (NTRS)

    Moss, Thomas; Ihlefeld, Curtis; Slack, Barry

    2010-01-01

    This system provides a portable means to detect gas flow through a thin-walled tube without breaking into the tubing system. The flow detection system was specifically designed to detect flow through two parallel branches of a manifold with only one inlet and outlet, and is a means for verifying a space shuttle program requirement that saves time and reduces the risk of flight hardware damage compared to the current means of requirement verification. The prototype Purge Vent and Drain Window Cavity Conditioning System (PVD WCCS) Flow Detection System consists of a heater and a temperature-sensing thermistor attached to a piece of Velcro to be attached to each branch of a WCCS manifold for the duration of the requirement verification test. The heaters and thermistors are connected to a shielded cable and then to an electronics enclosure, which contains the power supplies, relays, and circuit board to provide power, signal conditioning, and control. The electronics enclosure is then connected to a commercial data acquisition box to provide analog to digital conversion as well as digital control. This data acquisition box is then connected to a commercial laptop running a custom application created using National Instruments LabVIEW. The operation of the PVD WCCS Flow Detection System consists of first attaching a heater/thermistor assembly to each of the two branches of one manifold while there is no flow through the manifold. Next, the software application running on the laptop is used to turn on the heaters and to monitor the manifold branch temperatures. When the system has reached thermal equilibrium, the software application s graphical user interface (GUI) will indicate that the branch temperatures are stable. The operator can then physically open the flow control valve to initiate the test flow of gaseous nitrogen (GN2) through the manifold. Next, the software user interface will be monitored for stable temperature indications when the system is again at

  1. Arc fault detection system

    DOEpatents

    Jha, K.N.

    1999-05-18

    An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard. 1 fig.

  2. Arc fault detection system

    DOEpatents

    Jha, Kamal N.

    1999-01-01

    An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard.

  3. Monte Carlo simulation of pulse pile-up effect in gamma spectrum of a PGNAA system

    NASA Astrophysics Data System (ADS)

    Mowlavi, Ali Asghar; Hadizadeh Yazdi, Mohammad Hadi

    2011-12-01

    We have applied a pile-up Monte Carlo simulation code on gamma spectrum of a prompt gamma neutron activation analysis (PGNAA) system. The code has been run in nonparalyzable mode for a specific geometry of a PGNAA system with 241Am-9Be source and NaI(Tl) detector to obtain the distortion due to “pile-up” in the pulse height of gamma spectrum. The results show that the main background in the nitrogen region of interest (ROI) is due to two pile-ups. We have also evaluated the variation of count rate and total photon sampling over the Monte Carlo spectra. At high count rates, not only the nitrogen ROI but also carbon ROI, and hydrogen peak are disturbed strongly. Comparison between the results of simulations and the experimental spectra has shown a good agreement. The code could be used for other source setups and different gamma detection systems.

  4. Chandra Contributes to ESA's Integral Detection of Closest Gamma-Ray Burst

    NASA Astrophysics Data System (ADS)

    2004-08-01

    A gamma-ray burst detected by ESA's Integral gamma-ray observatory on 3 December 2003 has been thoroughly studied for months by an armada of space and ground-based observatories. Astronomers have now concluded that this event, called GRB 031203, is the closest cosmic gamma-ray burst on record, and also the faintest. This also suggests that an entire population of sub-energetic gamma-ray bursts has so far gone unnoticed. Cosmic gamma-ray bursts (GRBs) are flashes of gamma rays that can last from less than a second to a few minutes and occur at random positions in the sky. A large fraction of them is thought to result when a black hole is created from a dying star in a distant galaxy. Astronomers believe that a hot disc surrounding the black hole, made of gas and matter falling onto it, somehow emits an energetic beam parallel to the axis of rotation. According to the simplest picture, all GRBs should emit similar amounts of gamma-ray energy. The fraction of it detected at Earth should then depend on the 'width' (opening angle) and orientation of the beam as well as on the distance. The energy received should be larger when the beam is narrow or points towards us and smaller when the beam is broad or points away from us. New data collected with ESA's high energy observatories, Integral and XMM-Newton, now show that this picture is not so clear-cut and that the amount of energy emitted by GRBs can vary significantly. "The idea that all GRBs spit out the same amount of gamma rays, or that they are 'standard candles' as we call them, is simply ruled out by the new data," said Dr Sergey Sazonov, from the Space Research Institute of the Russian Academy of Sciences, Moscow (Russia) and the Max-Planck Institute for Astrophysics, Garching near Munich (Germany). Sazonov and an international team of researchers studied the GRB detected by Integral on 3 December 2003 and given the code-name of GRB 031203. Within a record 18 seconds of the burst, the Integral Burst Alert System

  5. Unified Mars detection system. [life detection

    NASA Technical Reports Server (NTRS)

    Martin, J. P.; Kok, B.; Radmer, R.; Johnson, R. D.

    1976-01-01

    A life-detection system is described which is designed to detect and characterize possible Martian biota and to gather information about the chemical environment of Mars, especially the water and amino acid contents of the soil. The system is organized around a central mass spectrometer that can sensitively analyze trace gases from a variety of different experiments. Some biological assays and soil-chemistry tests that have been performed in the laboratory as typical experiment candidates for the system are discussed, including tests for soil-organism metabolism, measurements of soil carbon contents, and determinations of primary aliphatic amines (amino acids and protein) in soils. Two possible test strategies are outlined, and the operational concept of the detection system is illustrated. Detailed descriptions are given for the mass spectrometer, gas inlet, incubation box, test cell modules, seal drive mechanism, soil distribution assembly, and electronic control system.

  6. Active Detection and Imaging of Nuclear Materials with High-Brightness Gamma Rays

    SciTech Connect

    Barty, C J; Gibson, D J; Albert, F; Anderson, S G; Anderson, G G; Betts, S M; Berry, R D; Fisher, S E; Hagmann, C A; Johnson, M S; Messerly, M J; Phan, H H; Semenov, V A; Shverdin, M Y; Tremaine, A M; Hartemann, F V; Siders, C W; McNabb, D P

    2009-02-26

    A Compton scattering {gamma}-ray source, capable of producing photons with energies ranging from 0.1 MeV to 0.9 MeV has been commissioned and characterized, and then used to perform nuclear resonance fluorescence (NRF) experiments. The performances of the two laser systems (one for electron production, one for scattering), the electron photoinjector, and the linear accelerator are also detailed, and {gamma}-ray results are presented. The key source parameters are the size (0.01 mm{sup 2}), horizontal and vertical divergence (6 x 10 mrad{sup 2}), duration (10 ps), spectrum and intensity (10{sup 5} photons/shot). These parameters are summarized by the peak brightness, 1.5 x 10{sup 15} photons/mm{sup 2}/mrad{sup 2}/s/0.1% bandwidth, measured at 478 keV. Additional measurements of the flux as a function of the timing difference between the drive laser pulse and the relativistic photo-electron bunch, {gamma}-ray beam profile, and background evaluations are presented. These results are systematically compared to theoretical models and computer simulations. NRF measurements performed on {sup 7}Li in LiH demonstrate the potential of Compton scattering photon sources to accurately detect isotopes in situ.

  7. The Intensity Distribution of Faint Gamma-Ray Bursts Detected with BATSE

    NASA Technical Reports Server (NTRS)

    Kommers, Jefferson M.; Lewin, Walter H. G.; Kouveliotou, Chryssa; VanParadijs, Jan; Pendleton, Geoffrey N.; Meegan, Charles A.; Fishman, Gerald J.

    2000-01-01

    We have recently completed a search of 6 years of archival BATSE data for gamma-ray bursts (GRBS) that were too faint to activate the real-time burst detection system running on board the spacecraft. These "nontriggered" bursts can be combined with the "triggered" bursts detected on board to produce a GRB intensity distribution that reaches peak fluxes a factor of approximately 2 lower than could be studied previously. The value of the statistic (in Euclidean space) for the bursts we detect is 0.177 plus or minus 0.006. This surprisingly low value is obtained because we detected very few bursts on the 4.096 s and 8.192 s timescales (where most bursts have their highest signal-to-noise ratio) that were not already detected on the 1.024 s timescale. If allowance is made for a power-law distribution of intrinsic peak luminosities, the extended peak flux distribution is consistent with models in which the redshift distribution of the gamma-ray burst rate approximately traces the star formation history of the universe. We argue that this class of models is preferred over those in which the burst rate is independent of redshift. We use the peak flux distribution to derive a limit of 10% (99% confidence) on the fraction of the total burst rate that could be contributed by a spatially homogeneous (in Euclidean space) subpopulation of burst sources, such as type lb/c supernovae. These results lend support to the conclusions of previous studies predicting that relatively few faint "classical" GRBs will be found below the BATSE onboard detection threshold.

  8. Renewed Gamma-Ray Emission from the blazar PKS 1510-089 Detected by AGILE

    NASA Astrophysics Data System (ADS)

    Munar-Adrover, P.; Pittori, C.; Bulgarelli, A.; Lucarelli, F.; Verrecchia, F.; Piano, G.; Fioretti, V.; Zoli, A.; Tavani, M.; Vercellone, S.; Minervini, G.; Striani, E.; Cardillo, M.; Gianotti, F.; Trifoglio, M.; Giuliani, A.; Mereghetti, S.; Caraveo, P.; Perotti, F.; Chen, A.; Argan, A.; Costa, E.; Del Monte, E.; Donnarumma, I.; Evangelista, Y.; Feroci, M.; Lazzarotto, F.; Lapshov, I.; Pacciani, L.; Soffitta, P.; Sabatini, S.; Vittorini, V.; Pucella, G.; Rapisarda, M.; Di Cocco, G.; Fuschino, F.; Galli, M.; Labanti, C.; Marisaldi, M.; Pellizzoni, A.; Pilia, M.; Trois, A.; Barbiellini, G.; Vallazza, E.; Longo, F.; Morselli, A.; Picozza, P.; Prest, M.; Lipari, P.; Zanello, D.; Cattaneo, P. W.; Rappoldi, A.; Colafrancesco, S.; Parmiggiani, N.; Ferrari, A.; Antonelli, A.; Giommi, P.; Salotti, L.; Valentini, G.; D'Amico, F.

    2016-09-01

    AGILE is currently detecting enhanced gamma-ray emission above 100 MeV from a source which position is consistent with the blazar PKS 1510-089. (the last activity of this source was reported in ATel #9350).

  9. Development of polarization-controlled multi-pass Thomson scattering system in the GAMMA 10 tandem mirror

    SciTech Connect

    Yoshikawa, M.; Morimoto, M.; Shima, Y.; Kohagura, J.; Sakamoto, M.; Nakashima, Y.; Imai, T.; Yasuhara, R.; Yamada, I.; Kawahata, K.; Funaba, H.; Minami, T.

    2012-10-15

    In the GAMMA 10 tandem mirror, the typical electron density is comparable to that of the peripheral plasma of torus-type fusion devices. Therefore, an effective method to increase Thomson scattering (TS) signals is required in order to improve signal quality. In GAMMA 10, the yttrium-aluminum-garnet (YAG)-TS system comprises a laser, incident optics, light collection optics, signal detection electronics, and a data recording system. We have been developing a multi-pass TS method for a polarization-based system based on the GAMMA 10 YAG TS. To evaluate the effectiveness of the polarization-based configuration, the multi-pass system was installed in the GAMMA 10 YAG-TS system, which is capable of double-pass scattering. We carried out a Rayleigh scattering experiment and applied this double-pass scattering system to the GAMMA 10 plasma. The integrated scattering signal was made about twice as large by the double-pass system.

  10. Gamma ray attenuation in a developed borate glassy system

    NASA Astrophysics Data System (ADS)

    Saeed, Aly; El shazly, R. M.; Elbashar, Y. H.; Abou El-azm, A. M.; El-Okr, M. M.; Comsan, M. N. H.; Osman, A. M.; Abdal-monem, A. M.; El-Sersy, A. R.

    2014-09-01

    Measurements and calculations of gamma ray attenuation coefficients in glass barriers of xBaO-5ZnO-5MgO-14Na2O--1Li2O-(75-x)B2O3, previously prepared by the melt-quenching technique [1], were performed for γ-ray of energies 121.8, 244.7, 344.14, 661.66, 778.7, 974, 1086.7, 1173.24, 1332.5, and 1407.9 keV; which emitted from 152Eu, 137Cs, and 60Co radioactive gamma ray sources. The transmitted γ-rays were detected by 3″×3″ and 5″×5″ NaI (Tl) scintillation γ-ray spectrometers, and a highly calibrated survey meter. The mass attenuation coefficients of γ-rays (σ(E) were deduced from the attenuation curves, while the WinXCom computer program (version 3.1) was used to calculate the mass attenuation coefficients of γ-rays for such energies at different barium concentrations of a glassy system. A good agreement between both experimental and theoretical results was achieved as well as results obtained by other workers in similar field.

  11. Discovery of a Highly Eccentric Binary Millisecond Pulsar in a Gamma-Ray-Detected Globular Cluster

    NASA Astrophysics Data System (ADS)

    DeCesar, Megan E.; Ransom, S. M.; Ray, P. S.; Kaplan, D. L.; Fermi Large Area Telescope Collaboration

    2014-01-01

    We report on the Green Bank Telescope discovery of a highly eccentric binary millisecond pulsar (MSP) in NGC 6652, the first MSP to be detected in this globular cluster. The pulsar search was guided by the Fermi Large Area Telescope, which detected NGC 6652 at GeV energies, identifying the cluster as a likely host of a population of gamma-ray-emitting MSPs. Initial timing of the MSP yielded an eccentricity of ~0.95 and a minimum companion mass of 0.73 solar masses, assuming a neutron star mass of 1.4 solar masses. These results strongly indicate that the pulsar has undergone one or more companion exchanges in the dense stellar environment of the cluster, and that the current companion is a compact object, likely a massive white dwarf or a neutron star. Further timing of this system will result in a measurement of the post-Keplerian rate of periastron advance and therefore a direct measurement of the total system mass, allowing additional constraints to be placed on both the pulsar and companion masses. The timing solution will also be used to search for gamma-ray pulsations from the MSP.

  12. Neonatal Jaundice Detection System.

    PubMed

    Aydın, Mustafa; Hardalaç, Fırat; Ural, Berkan; Karap, Serhat

    2016-07-01

    Neonatal jaundice is a common condition that occurs in newborn infants in the first week of life. Today, techniques used for detection are required blood samples and other clinical testing with special equipment. The aim of this study is creating a non-invasive system to control and to detect the jaundice periodically and helping doctors for early diagnosis. In this work, first, a patient group which is consisted from jaundiced babies and a control group which is consisted from healthy babies are prepared, then between 24 and 48 h after birth, 40 jaundiced and 40 healthy newborns are chosen. Second, advanced image processing techniques are used on the images which are taken with a standard smartphone and the color calibration card. Segmentation, pixel similarity and white balancing methods are used as image processing techniques and RGB values and pixels' important information are obtained exactly. Third, during feature extraction stage, with using colormap transformations and feature calculation, comparisons are done in RGB plane between color change values and the 8-color calibration card which is specially designed. Finally, in the bilirubin level estimation stage, kNN and SVR machine learning regressions are used on the dataset which are obtained from feature extraction. At the end of the process, when the control group is based on for comparisons, jaundice is succesfully detected for 40 jaundiced infants and the success rate is 85 %. Obtained bilirubin estimation results are consisted with bilirubin results which are obtained from the standard blood test and the compliance rate is 85 %. PMID:27229489

  13. The AGILE Alert System for Gamma-Ray Transients

    NASA Astrophysics Data System (ADS)

    Bulgarelli, A.; Trifoglio, M.; Gianotti, F.; Tavani, M.; Parmiggiani, N.; Fioretti, V.; Chen, A. W.; Vercellone, S.; Pittori, C.; Verrecchia, F.; Lucarelli, F.; Santolamazza, P.; Fanari, G.; Giommi, P.; Beneventano, D.; Argan, A.; Trois, A.; Scalise, E.; Longo, F.; Pellizzoni, A.; Pucella, G.; Colafrancesco, S.; Conforti, V.; Tempesta, P.; Cerone, M.; Sabatini, P.; Annoni, G.; Valentini, G.; Salotti, L.

    2014-01-01

    In recent years, a new generation of space missions has offered great opportunities for discovery in high-energy astrophysics. In this article we focus on the scientific operations of the Gamma-Ray Imaging Detector (GRID) on board the AGILE space mission. AGILE-GRID, sensitive in the energy range of 30 MeV-30 GeV, has detected many γ-ray transients of both galactic and extragalactic origin. This work presents the AGILE innovative approach to fast γ-ray transient detection, which is a challenging task and a crucial part of the AGILE scientific program. The goals are to describe (1) the AGILE Gamma-Ray Alert System, (2) a new algorithm for blind search identification of transients within a short processing time, (3) the AGILE procedure for γ-ray transient alert management, and (4) the likelihood of ratio tests that are necessary to evaluate the post-trial statistical significance of the results. Special algorithms and an optimized sequence of tasks are necessary to reach our goal. Data are automatically analyzed at every orbital downlink by an alert pipeline operating on different timescales. As proper flux thresholds are exceeded, alerts are automatically generated and sent as SMS messages to cellular telephones, via e-mail, and via push notifications from an application for smartphones and tablets. These alerts are crosschecked with the results of two pipelines, and a manual analysis is performed. Being a small scientific-class mission, AGILE is characterized by optimization of both scientific analysis and ground-segment resources. The system is capable of generating alerts within two to three hours of a data downlink, an unprecedented reaction time in γ-ray astrophysics.

  14. The agile alert system for gamma-ray transients

    SciTech Connect

    Bulgarelli, A.; Trifoglio, M.; Gianotti, F.; Fioretti, V.; Chen, A. W.; Pittori, C.; Verrecchia, F.; Lucarelli, F.; Santolamazza, P.; Fanari, G.; Giommi, P.; Pellizzoni, A.; and others

    2014-01-20

    In recent years, a new generation of space missions has offered great opportunities for discovery in high-energy astrophysics. In this article we focus on the scientific operations of the Gamma-Ray Imaging Detector (GRID) on board the AGILE space mission. AGILE-GRID, sensitive in the energy range of 30 MeV-30 GeV, has detected many γ-ray transients of both galactic and extragalactic origin. This work presents the AGILE innovative approach to fast γ-ray transient detection, which is a challenging task and a crucial part of the AGILE scientific program. The goals are to describe (1) the AGILE Gamma-Ray Alert System, (2) a new algorithm for blind search identification of transients within a short processing time, (3) the AGILE procedure for γ-ray transient alert management, and (4) the likelihood of ratio tests that are necessary to evaluate the post-trial statistical significance of the results. Special algorithms and an optimized sequence of tasks are necessary to reach our goal. Data are automatically analyzed at every orbital downlink by an alert pipeline operating on different timescales. As proper flux thresholds are exceeded, alerts are automatically generated and sent as SMS messages to cellular telephones, via e-mail, and via push notifications from an application for smartphones and tablets. These alerts are crosschecked with the results of two pipelines, and a manual analysis is performed. Being a small scientific-class mission, AGILE is characterized by optimization of both scientific analysis and ground-segment resources. The system is capable of generating alerts within two to three hours of a data downlink, an unprecedented reaction time in γ-ray astrophysics.

  15. Detection of 16 gamma-ray pulsars through blind frequency searches using the Fermi LAT.

    PubMed

    Abdo, A A; Ackermann, M; Ajello, M; Anderson, B; Atwood, W B; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Baughman, B M; Bechtol, K; Bellazzini, R; Berenji, B; Bignami, G F; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, T H; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Celik, O; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Cutini, S; Dermer, C D; de Angelis, A; de Luca, A; de Palma, F; Digel, S W; Dormody, M; do Couto e Silva, E; Drell, P S; Dubois, R; Dumora, D; Farnier, C; Favuzzi, C; Fegan, S J; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giommi, P; Giordano, F; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M-H; Grove, J E; Guillemot, L; Guiriec, S; Gwon, C; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hughes, R E; Jóhannesson, G; Johnson, R P; Johnson, T J; Johnson, W N; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Kerr, M; Knödlseder, J; Kocian, M L; Kuss, M; Lande, J; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Marelli, M; Mazziotta, M N; McConville, W; McEnery, J E; Meurer, C; Michelson, P F; Mitthumsiri, W; Mizuno, T; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nolan, P L; Norris, J P; Nuss, E; Ohsugi, T; Omodei, N; Orlando, E; Ormes, J F; Paneque, D; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Pierbattista, M; Piron, F; Porter, T A; Primack, J R; Rainò, S; Rando, R; Ray, P S; Razzano, M; Rea, N; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Rochester, L S; Rodriguez, A Y; Romani, R W; Ryde, F; Sadrozinski, H F-W; Sanchez, D; Sander, A; Saz Parkinson, P M; Scargle, J D; Sgrò, C; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Starck, J-L; Strickman, M S; Suson, D J; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, J G; Thompson, D J; Tibaldo, L; Tibolla, O; Torres, D F; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, T L; Van Etten, A; Vasileiou, V; Vilchez, N; Vitale, V; Waite, A P; Wang, P; Watters, K; Winer, B L; Wolff, M T; Wood, K S; Ylinen, T; Ziegler, M

    2009-08-14

    Pulsars are rapidly rotating, highly magnetized neutron stars emitting radiation across the electromagnetic spectrum. Although there are more than 1800 known radio pulsars, until recently only seven were observed to pulse in gamma rays, and these were all discovered at other wavelengths. The Fermi Large Area Telescope (LAT) makes it possible to pinpoint neutron stars through their gamma-ray pulsations. We report the detection of 16 gamma-ray pulsars in blind frequency searches using the LAT. Most of these pulsars are coincident with previously unidentified gamma-ray sources, and many are associated with supernova remnants. Direct detection of gamma-ray pulsars enables studies of emission mechanisms, population statistics, and the energetics of pulsar wind nebulae and supernova remnants. PMID:19574346

  16. Detecting special nuclear materials in suspect containers using high-energy gamma rays emitted by fission products

    DOEpatents

    Norman, Eric B [Oakland, CA; Prussin, Stanley G [Kensington, CA

    2009-05-05

    A method and a system for detecting the presence of special nuclear materials in a suspect container. The system and its method include irradiating the suspect container with a beam of neutrons, so as to induce a thermal fission in a portion of the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the thermal fission, to produce a detector signal, comparing the detector signal with a threshold value to form a comparison, and detecting the presence of the special nuclear materials using the comparison.

  17. Detecting special nuclear materials in suspect containers using high-energy gamma rays emitted by fission products

    DOEpatents

    Norman, Eric B.; Prussin, Stanley G.

    2009-01-06

    A method and a system for detecting the presence of special nuclear materials in a suspect container. The system and its method include irradiating the suspect container with a beam of neutrons, so as to induce a thermal fission in a portion of the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the thermal fission, to produce a detector signal, comparing the detector signal with a threshold value to form a comparison, and detecting the presence of the special nuclear materials using the comparison.

  18. Detecting special nuclear materials in suspect containers using high-energy gamma rays emitted by fission products

    DOEpatents

    Norman, Eric B.; Prussin, Stanley G.

    2009-01-27

    A method and a system for detecting the presence of special nuclear materials in a suspect container. The system and its method include irradiating the suspect container with a beam of neutrons, so as to induce a thermal fission in a portion of the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the thermal fission, to produce a detector signal, comparing the detector signal with a threshold value to form a comparison, and detecting the presence of the special nuclear materials using the comparison.

  19. The Advanced Gamma-Ray Imaging System (AGIS): Science Highlights

    SciTech Connect

    Buckley, J.; Coppi, P.; Digel, S.; Funk, S.; Krawczynski, H.; Krennrich, F.; Pohl, M.; Romani, R.; Vassiliev, V.; /UCLA

    2011-11-21

    The Advanced Gamma-ray Imaging System (AGIS), a future gamma-ray telescope consisting of an array of {approx}50 atmospheric Cherenkov telescopes distributed over an area of {approx}1 km{sup 2}, will provide a powerful new tool for exploring the high-energy universe. The order-of-magnitude increase in sensitivity and improved angular resolution could provide the first detailed images of {gamma}-ray emission from other nearby galaxies or galaxy clusters. The large effective area will provide unprecedented sensitivity to short transients (such as flares from AGNs and GRBs) probing both intrinsic spectral variability (revealing the details of the acceleration mechanism and geometry) as well as constraining the high-energy dispersion in the velocity of light (probing the structure of spacetime and Lorentz invariance). A wide field of view ({approx}4 times that of current instruments) and excellent angular resolution (several times better than current instruments) will allow for an unprecedented survey of the Galactic plane, providing a deep unobscured survey of SNRs, X-ray binaries, pulsar-wind nebulae, molecular cloud complexes and other sources. The differential flux sensitivity of {approx}10{sup -13} erg cm{sup -2} sec{sup -1} will rival the most sensitive X-ray instruments for these extended Galactic sources. The excellent capabilities of AGIS at energies below 100 GeV will provide sensitivity to AGN and GRBs out to cosmological redshifts, increasing the number of AGNs detected at high energies from about 20 to more than 100, permitting population studies that will provide valuable insights into both a unified model for AGN and a detailed measurement of the effects of intergalactic absorption from the diffuse extragalactic background light. A new instrument with fast-slewing wide-field telescopes could provide detections of a number of long-duration GRBs providing important physical constraints from this new spectral component. The new array will also have excellent

  20. Gamma-ray imaging system. Innovative technology summary report

    SciTech Connect

    1998-11-01

    The RadScan 600 gamma-ray imaging system is designed to survey large surface areas for radiological contamination with accuracy and efficiency. The resulting survey data are clear, concise, and precise in describing how much contamination is present at exact locations. Data can be permanently stored electronically and on video tape, making storage and retrieval economical and efficient. This technology can perform accurate measurements in high radiation contamination areas while minimizing worker exposure. The RadScan 600 system is a safe and effective alternative to hand-held radiation detection devices. Performance data of the demonstrated survey area of the RadScan 600 system versus the baseline, which is the hand-held radiation detection devices (RO-2 and RO-7) for a given survey, production rate is 72% of the baseline. It should be noted that the innovative technology provides 100% coverage at a unit cost of $8.64/m{sup 2} versus a static measurement of a unit cost of $1.61/m{sup 2} for the baseline.

  1. Gamma-ray nuclear resonance absorption (γ-NRA) for explosives detection in air cargo

    NASA Astrophysics Data System (ADS)

    Vartsky, D.; Goldberg, M. B.; Engler, G.; Goldschmidt, A.; Feldman, G.; Bar, D.; Sayag, E.; Katz, D.; Krauss, R. A.

    1999-06-01

    The γ-NRA method has been utilized to detect explosives concealed in aviation containers loaded with a variety of cargo. In γ-NRA, gamma-rays at an energy of 9.17 MeV undergo a resonant nuclear attenuation component proportional to the integrated density of 14N nuclei along the line of sight from source to detector. When inspecting objects in transmission mode, projected images of nitrogen density of their contents can be generated. In an experiment performed earlier this year at the Dynamitron accelerator lab. of Birmingham Univ., U.K., diverse items such as passenger bags, electronic equipment, paper goods and mixed cargo were scanned along with explosives simulants. The results from this run will be presented and anticipated performance ratings of an operational explosives detection system (EDS) discussed.

  2. Modeling the Production of Beta-Delayed Gamma Rays for the Detection of Special Nuclear Materials

    SciTech Connect

    Hall, J M; Pruet, J A; Brown, D A; Descalle, M; Hedstrom, G W; Prussin, S G

    2005-02-14

    The objective of this LDRD project was to develop one or more models for the production of {beta}-delayed {gamma} rays following neutron-induced fission of a special nuclear material (SNM) and to define a standardized formatting scheme which will allow them to be incorporated into some of the modern, general-purpose Monte Carlo transport codes currently being used to simulate inspection techniques proposed for detecting fissionable material hidden in sea-going cargo containers. In this report, we will describe a Monte Carlo model for {beta}-delayed {gamma}-ray emission following the fission of SNM that can accommodate arbitrary time-dependent fission rates and photon collection histories. The model involves direct sampling of the independent fission yield distributions of the system, the branching ratios for decay of individual fission products and spectral distributions representing photon emission from each fission product and for each decay mode. While computationally intensive, it will be shown that this model can provide reasonably detailed estimates of the spectra that would be recorded by an arbitrary spectrometer and may prove quite useful in assessing the quality of evaluated data libraries and identifying gaps in the libraries. The accuracy of the model will be illustrated by comparing calculated and experimental spectra from the decay of short-lived fission products following the reactions {sup 235}U(n{sub th}, f) and {sup 239}Pu(n{sub th}, f). For general-purpose transport calculations, where a detailed consideration of the large number of individual {gamma}-ray transitions in a spectrum may not be necessary, it will be shown that a simple parameterization of the {gamma}-ray source function can be defined which provides high-quality average spectral distributions that should suffice for calculations describing photons being transported through thick attenuating media. Finally, a proposal for ENDF-compatible formats that describe each of the models and

  3. Prototype explosives detection system based on nuclear resonance absorption in nitrogen

    SciTech Connect

    Morgado, R.E.; Arnone, G.J.; Cappiello, C.C.

    1996-05-01

    A laboratory prototype system has been developed for the experimental evaluation of an explosives detection technique based on nuclear resonance absorption of gamma rays in nitrogen. Major subsystems include a radiofrequency quadrupole proton accelerator and associated beam transport system, a high-power gamma-ray production target, an airline-luggage tomographic inspection system, and an image- processing/detection-alarm subsystem. The detection system performance, based on a limited experimental test, is reported.

  4. Gamma Ray Imaging System (GRIS) GammaCam{trademark}. Final report, January 3, 1994--May 31, 1996

    SciTech Connect

    1996-12-31

    This report describes the activities undertaken during the development of the Gamma Ray Imaging System (GRIS) program now referred to as the GammaCam{trademark}. The purpose of this program is to develop a 2-dimensional imaging system for gamma-ray energy scenes that may be present in nuclear power plants. The report summarizes the overall accomplishments of the program and the most recent GammaCam measurements made at LANL and Estonia. The GammaCam is currently available for sale from AIL Systems as an off-the-shelf instrument.

  5. System to quantify gamma-ray radial energy deposition in semiconductor detectors

    DOEpatents

    Kammeraad, Judith E.; Blair, Jerome J.

    2001-01-01

    A system for measuring gamma-ray radial energy deposition is provided for use in conjunction with a semiconductor detector. The detector comprises two electrodes and a detector material, and defines a plurality of zones within the detecting material in parallel with the two electrodes. The detector produces a charge signal E(t) when a gamma-ray interacts with the detector. Digitizing means are provided for converting the charge signal E(t) into a digitized signal. A computational means receives the digitized signal and calculates in which of the plurality of zones the gamma-ray deposited energy when interacting with the detector. The computational means produces an output indicating the amount of energy deposited by the gamma-ray in each of the plurality of zones.

  6. Implementation of gamma-ray instrumentation for solid solar system bodies using neutron activation method

    NASA Astrophysics Data System (ADS)

    Litvak, M. L.; Golovin, D. V.; Jun, I.; Kozyrev, A. S.; Mitrofanov, I. G.; Sanin, A. B.; Shvetsov, V. N.; Timoshenko, G. N.; Zontikov, A.

    2016-06-01

    In this paper we present the results of ground tests performed with a flight model and with industry prototypes of passive and active gamma ray spectrometers with the objective of understanding their capability to distinguish the elemental composition of planetary bodies in the solar system. The gamma instrumentation, which was developed for future space missions was used in the measurements at a special ground test facility where a simulant of planetary material was fabricated with a martian-like composition. In this study, a special attention was paid to the gamma lines from activation reaction products generated by a pulsed neutron generator. The instrumentation was able to detect and identify gamma lines attributed to O, Na, Mg, Al, Si, K, Ca and Fe.

  7. 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.

  8. Gamma-range synchronization of fast-spiking interneurons can enhance detection of tactile stimuli

    PubMed Central

    Siegle, Joshua H.; Pritchett, Dominique L.; Moore, Christopher I.

    2014-01-01

    We tested the sensory impact of repeated synchronization of fast-spiking interneurons (FS), an activity pattern thought to underlie neocortical gamma oscillations. We optogenetically drove “FS-gamma” while mice detected naturalistic vibrissal stimuli and found enhanced detection of less salient stimuli and impaired detection of more salient ones. Prior studies have predicted that the benefit of FS-gamma is generated when sensory neocortical excitation arrives in a specific temporal window 20-25 ms after FS synchronization. To systematically test this prediction, we aligned periodic tactile and optogenetic stimulation. We found that the detection of less salient stimuli was improved only when peripheral drive led to the arrival of excitation 20-25 ms after synchronization and that other temporal alignments either had no effects or impaired detection. These results provide causal evidence that FS-gamma can enhance processing of less salient stimuli, those that benefit from the allocation of attention. PMID:25151266

  9. Intelligent Leak Detection System

    Energy Science and Technology Software Center (ESTSC)

    2014-10-27

    apability of underground carbon dioxide storage to confine and sustain injected CO2 for a very long time is the main concern for geologic CO2 sequestration. If a leakage from a geological CO2 sequestration site occurs, it is crucial to find the approximate amount and the location of the leak in order to implement proper remediation activity. An overwhelming majority of research and development for storage site monitoring has been concentrated on atmospheric, surface or nearmore » surface monitoring of the sequestered CO2. This study aims to monitor the integrity of CO2 storage at the reservoir level. This work proposes developing in-situ CO2 Monitoring and Verification technology based on the implementation of Permanent Down-hole Gauges (PDG) or “Smart Wells” along with Artificial Intelligence and Data Mining (AI&DM). The technology attempts to identify the characteristics of the CO2 leakage by de-convolving the pressure signals collected from Permanent Down-hole Gauges (PDG). Citronelle field, a saline aquifer reservoir, located in the U.S. was considered for this study. A reservoir simulation model for CO2 sequestration in the Citronelle field was developed and history matched. The presence of the PDGs were considered in the reservoir model at the injection well and an observation well. High frequency pressure data from sensors were collected based on different synthetic CO2 leakage scenarios in the model. Due to complexity of the pressure signal behaviors, a Machine Learning-based technology was introduced to build an Intelligent Leakage Detection System (ILDS). The ILDS was able to detect leakage characteristics in a short period of time (less than a day) demonstrating the capability of the system in quantifying leakage characteristics subject to complex rate behaviors. The performance of ILDS was examined under different conditions such as multiple well leakages, cap rock leakage, availability of an additional monitoring well, presence of pressure drift

  10. Intelligent Leak Detection System

    SciTech Connect

    Mohaghegh, Shahab D.

    2014-10-27

    apability of underground carbon dioxide storage to confine and sustain injected CO2 for a very long time is the main concern for geologic CO2 sequestration. If a leakage from a geological CO2 sequestration site occurs, it is crucial to find the approximate amount and the location of the leak in order to implement proper remediation activity. An overwhelming majority of research and development for storage site monitoring has been concentrated on atmospheric, surface or near surface monitoring of the sequestered CO2. This study aims to monitor the integrity of CO2 storage at the reservoir level. This work proposes developing in-situ CO2 Monitoring and Verification technology based on the implementation of Permanent Down-hole Gauges (PDG) or “Smart Wells” along with Artificial Intelligence and Data Mining (AI&DM). The technology attempts to identify the characteristics of the CO2 leakage by de-convolving the pressure signals collected from Permanent Down-hole Gauges (PDG). Citronelle field, a saline aquifer reservoir, located in the U.S. was considered for this study. A reservoir simulation model for CO2 sequestration in the Citronelle field was developed and history matched. The presence of the PDGs were considered in the reservoir model at the injection well and an observation well. High frequency pressure data from sensors were collected based on different synthetic CO2 leakage scenarios in the model. Due to complexity of the pressure signal behaviors, a Machine Learning-based technology was introduced to build an Intelligent Leakage Detection System (ILDS). The ILDS was able to detect leakage characteristics in a short period of time (less than a day) demonstrating the capability of the system in quantifying leakage characteristics subject to complex rate behaviors. The performance of ILDS was examined under different conditions such as multiple well leakages, cap rock leakage, availability of an additional monitoring well, presence of pressure drift and noise

  11. The Advanced Gamma-ray Imaging System (AGIS): Simulation studies

    SciTech Connect

    Maier, G.; Buckley, J.; Bugaev, V.; Fegan, S.; Funk, S.; Konopelko, A.; Vassiliev, V.V.; /UCLA

    2011-06-14

    The Advanced Gamma-ray Imaging System (AGIS) is a next-generation ground-based gamma-ray observatory being planned in the U.S. The anticipated sensitivity of AGIS is about one order of magnitude better than the sensitivity of current observatories, allowing it to measure gamma-ray emission from a large number of Galactic and extra-galactic sources. We present here results of simulation studies of various possible designs for AGIS. The primary characteristics of the array performance - collecting area, angular resolution, background rejection, and sensitivity - are discussed.

  12. Incipient fire detection system

    DOEpatents

    Brooks, Jr., William K.

    1999-01-01

    A method and apparatus for an incipient fire detection system that receives gaseous samples and measures the light absorption spectrum of the mixture of gases evolving from heated combustibles includes a detector for receiving gaseous samples and subjecting the samples to spectroscopy and determining wavelengths of absorption of the gaseous samples. The wavelengths of absorption of the gaseous samples are compared to predetermined absorption wavelengths. A warning signal is generated whenever the wavelengths of absorption of the gaseous samples correspond to the predetermined absorption wavelengths. The method includes receiving gaseous samples, subjecting the samples to light spectroscopy, determining wavelengths of absorption of the gaseous samples, comparing the wavelengths of absorption of the gaseous samples to predetermined absorption wavelengths and generating a warning signal whenever the wavelengths of absorption of the gaseous samples correspond to the predetermined absorption wavelengths. In an alternate embodiment, the apparatus includes a series of channels fluidically connected to a plurality of remote locations. A pump is connected to the channels for drawing gaseous samples into the channels. A detector is connected to the channels for receiving the drawn gaseous samples and subjecting the samples to spectroscopy. The wavelengths of absorption are determined and compared to predetermined absorption wavelengths is provided. A warning signal is generated whenever the wavelengths correspond.

  13. A simultaneous beta and coincidence-gamma imaging system for plant leaves

    NASA Astrophysics Data System (ADS)

    Ranjbar, Homayoon; Wen, Jie; Mathews, Aswin J.; Komarov, Sergey; Wang, Qiang; Li, Ke; O’Sullivan, Joseph A.; Tai, Yuan-Chuan

    2016-05-01

    Positron emitting isotopes, such as 11C, 13N, and 18F, can be used to label molecules. The tracers, such as 11CO2, are delivered to plants to study their biological processes, particularly metabolism and photosynthesis, which may contribute to the development of plants that have a higher yield of crops and biomass. Measurements and resulting images from PET scanners are not quantitative in young plant structures or in plant leaves due to poor positron annihilation in thin objects. To address this problem we have designed, assembled, modeled, and tested a nuclear imaging system (simultaneous beta–gamma imager). The imager can simultaneously detect positrons ({β+} ) and coincidence-gamma rays (γ). The imaging system employs two planar detectors; one is a regular gamma detector which has a LYSO crystal array, and the other is a phoswich detector which has an additional BC-404 plastic scintillator for beta detection. A forward model for positrons is proposed along with a joint image reconstruction formulation to utilize the beta and coincidence-gamma measurements for estimating radioactivity distribution in plant leaves. The joint reconstruction algorithm first reconstructs beta and gamma images independently to estimate the thickness component of the beta forward model and afterward jointly estimates the radioactivity distribution in the object. We have validated the physics model and reconstruction framework through a phantom imaging study and imaging a tomato leaf that has absorbed 11CO2. The results demonstrate that the simultaneously acquired beta and coincidence-gamma data, combined with our proposed joint reconstruction algorithm, improved the quantitative accuracy of estimating radioactivity distribution in thin objects such as leaves. We used the structural similarity (SSIM) index for comparing the leaf images from the simultaneous beta–gamma imager with the ground truth image. The jointly reconstructed images yield SSIM indices of 0.69 and 0.63, whereas

  14. Systems for detecting charged particles in object inspection

    SciTech Connect

    Morris, Christopher L.; Makela, Mark F.

    2013-08-20

    Techniques, apparatus and systems for detecting particles such as muons. In one implementation, a monitoring system has a cosmic ray-produced charged particle tracker with a plurality of drift cells. The drift cells, which can be for example aluminum drift tubes, can be arranged at least above and below a volume to be scanned to thereby track incoming and outgoing charged particles, such as cosmic ray-produced muons, while also detecting gamma rays. The system can selectively detect devices or materials, such as iron, lead, gold and/or tungsten, occupying the volume from multiple scattering of the charged particles passing through the volume and can also detect any radioactive sources occupying the volume from gamma rays emitted therefrom. If necessary, the drift tubes can be sealed to eliminate the need for a gas handling system. The system can be employed to inspect occupied vehicles at border crossings for nuclear threat objects.

  15. Constraining Gamma-Ray Emission from Luminous Infrared Galaxies with Fermi-LAT; Tentative Detection of Arp 220

    NASA Astrophysics Data System (ADS)

    Griffin, Rhiannon D.; Dai, Xinyu; Thompson, Todd A.

    2016-05-01

    Star-forming galaxies produce gamma-rays primarily via pion production, resulting from inelastic collisions between cosmic-ray protons and the interstellar medium (ISM). The dense ISM and high star formation rates of luminous and ultra-luminous infrared galaxies (LIRGs and ULIRGs) imply that they should be strong gamma-ray emitters, but so far only two LIRGs have been detected. Theoretical models for their emission depend on the unknown fraction of cosmic-ray protons that escape these galaxies before interacting. We analyze Fermi-LAT data for 82 of the brightest Infrared Astronomical Satellite LIRGs and ULIRGs. We examine each system individually and carry out a stacking analysis to constrain their gamma-ray fluxes. We report the detection of the nearest ULIRG Arp 220 (˜4.6σ). We observe a gamma-ray flux (0.8–100 GeV) of 2.4 × 10‑10 phot cm‑2 s‑1 with a photon index of 2.23 (8.2 × 1041 erg s‑1 at 77 Mpc). We also derive upper limits (ULs) for the stacked LIRGs and ULIRGs. The gamma-ray luminosity of Arp 220 and the stacked ULs agree with calorimetric predictions for dense star-forming galaxies. With the detection of Arp 220, we extend the gamma-ray–IR luminosity correlation to the high-luminosity regime with {log}{L}0.1-100{GeV}=1.25× {log}{L}8-1000μ {{m}}+26.7 as well as the gamma-ray–radio continuum luminosity correlation with {log}{L}0.1-100{GeV}=1.22× {log}{L}1.4{GHz}+13.3. The current survey of Fermi-LAT is on the verge of detecting more LIRGs/ULIRGs in the local universe, and we expect even more detections with deeper Fermi-LAT observations or the next generation of gamma-ray detectors.

  16. Constraining Gamma-Ray Emission from Luminous Infrared Galaxies with Fermi-LAT; Tentative Detection of Arp 220

    NASA Astrophysics Data System (ADS)

    Griffin, Rhiannon D.; Dai, Xinyu; Thompson, Todd A.

    2016-05-01

    Star-forming galaxies produce gamma-rays primarily via pion production, resulting from inelastic collisions between cosmic-ray protons and the interstellar medium (ISM). The dense ISM and high star formation rates of luminous and ultra-luminous infrared galaxies (LIRGs and ULIRGs) imply that they should be strong gamma-ray emitters, but so far only two LIRGs have been detected. Theoretical models for their emission depend on the unknown fraction of cosmic-ray protons that escape these galaxies before interacting. We analyze Fermi-LAT data for 82 of the brightest Infrared Astronomical Satellite LIRGs and ULIRGs. We examine each system individually and carry out a stacking analysis to constrain their gamma-ray fluxes. We report the detection of the nearest ULIRG Arp 220 (∼4.6σ). We observe a gamma-ray flux (0.8–100 GeV) of 2.4 × 10‑10 phot cm‑2 s‑1 with a photon index of 2.23 (8.2 × 1041 erg s‑1 at 77 Mpc). We also derive upper limits (ULs) for the stacked LIRGs and ULIRGs. The gamma-ray luminosity of Arp 220 and the stacked ULs agree with calorimetric predictions for dense star-forming galaxies. With the detection of Arp 220, we extend the gamma-ray–IR luminosity correlation to the high-luminosity regime with {log}{L}0.1-100{GeV}=1.25× {log}{L}8-1000μ {{m}}+26.7 as well as the gamma-ray–radio continuum luminosity correlation with {log}{L}0.1-100{GeV}=1.22× {log}{L}1.4{GHz}+13.3. The current survey of Fermi-LAT is on the verge of detecting more LIRGs/ULIRGs in the local universe, and we expect even more detections with deeper Fermi-LAT observations or the next generation of gamma-ray detectors.

  17. Suppression of gamma-ray sensitivity of liquid scintillators for neutron detection

    NASA Astrophysics Data System (ADS)

    Swiderski, L.; Moszyński, M.; Wolski, D.; Iwanowska, J.; Szczęśniak, T.; Schotanus, P.; Hurlbut, C.

    2011-10-01

    Methods to reduce gamma-ray sensitivity of a liquid scintillator EJ309 have been studied. Zero-crossing pulse shape discrimination method was used to separate events generated by neutron and gamma radiation between 60- keVee and 4 MeVee. The measurements were carried out under irradiation from an intense 137Cs source, yielding dose rate of 10 mR/h at the detector. A Pu-Be source was used to establish neutron integration window. Pile-up rejection (PUR) circuit was used to reduce gamma-ray induced events under irradiation from an intense gamma-ray source. Further, application of lead, tin and copper shields was done in order to decrease intrinsic gamma-neutron detection efficiency.

  18. Millisecond Pulsars at Gamma-Ray Energies: Fermi Detections and Implications

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    2011-01-01

    The Fermi Gamma-Ray Space Telescope has revolutionized the study of pulsar physics with the discovery of new populations of radio quiet and millisecond gamma-ray pulsars. The Fermi Large Area Telescope has so far discovered approx.20 new gamma-ray millisecond pulsars (MSPs) by both folding at periods of known radio MSPs or by detecting them as gamma-ray sources that are followed up by radio pulsar searches. The second method has resulted in a phenomenally successful synergy, with -30 new radio MSPs (to date) having been discovered at Fermi unidentified source locations and the gamma-ray pulsations having then been detected in a number of these using the radio timing solutions. Many of the newly discovered MSPs may be suitable for addition to the collection of very stable MSPs used for gravitational wave detection. Detection of such a large number of MSPs was surprising, given that most have relatively low spin-down luminosity and surface field strength. I will discuss their properties and the implications for pulsar particle acceleration and emission, as well as their potential contribution to gamma-ray backgrounds and Galactic cosmic rays.

  19. Modeling of gamma/gamma-prime phase equilibrium in the nickel-aluminum system

    NASA Technical Reports Server (NTRS)

    Sanchez, J. M.; Barefoot, J. R.; Jarrett, R. N.; Tien, J. K.

    1984-01-01

    A theoretical model is proposed for the determination of phase equilibrium in alloys, taking into consideration dissimilar lattice parameters. Volume-dependent pair interactions are introduced by means of phenomenological Lennard-Jones potentials and the configurational entropy of the system is treated in the tetrahedron approximation of the cluster variation method. The model is applied to the superalloy-relevant, nickel-rich, gamma/gamma-prime phase region of the Ni-Al phase diagram. The model predicts reasonable values for the lattice parameters and the enthalpy of formation as a function of composition, and the calculated phase diagram closely approximates the experimental diagram.

  20. Isotope-specific detection of low density materials with mono-energetic (gamma)-rays

    SciTech Connect

    Albert, F; Anderson, S G; Gibson, D J; Hagmann, C A; Johnson, M S; Messerly, M J; Semenov, V A; Shverdin, M Y; Tremaine, A M; Hartemann, F V; Siders, C W; McNabb, D P; Barty, C J

    2009-03-16

    The first demonstration of isotope-specific detection of a low-Z, low density object, shielded by a high-Z and high density material using mono-energetic gamma-rays is reported. Isotope-specific detection of LiH shielded by Pb and Al is accomplished using the nuclear resonance fluorescence line of {sup 7}Li at 0.478 MeV. Resonant photons are produced via laser-based Compton scattering. The detection techniques are general and the confidence level obtained is shown to be superior to that yielded by conventional x-ray/{gamma}-ray techniques in these situations.

  1. Neutron detection in a high gamma ray background with liquid scintillators

    SciTech Connect

    Stevanato, L.; Cester, D.; Viesti, G.; Nebbia, G.

    2013-04-19

    The capability of liquid scintillator (namely 2'' Multiplication-Sign 2'' cells of EJ301 and EJ309) of detecting neutrons in a very high gamma ray background is explored. A weak {sup 252}Cf source has been detected in a high {sup 137}Cs gamma ray background corresponding to a dose rate of 100 {mu}Sv/h with probability of detection in compliance with IEC requirements for hand held instruments. Tests were performed with new generation of CAEN digitizers, in particular the V1720 (8 Channel 12bit 250 MS/s) one.

  2. Bismuth- and lithium-loaded plastic scintillators for gamma and neutron detection

    NASA Astrophysics Data System (ADS)

    Cherepy, Nerine J.; Sanner, Robert D.; Beck, Patrick R.; Swanberg, Erik L.; Tillotson, Thomas M.; Payne, Stephen A.; Hurlbut, Charles R.

    2015-04-01

    Transparent plastic scintillators based on polyvinyltoluene (PVT) have been fabricated with high loading of bismuth carboxylates for gamma spectroscopy, and with lithium carboxylates for neutron detection. When activated with a combination of standard fluors, 2,5-diphenyloxazole (PPO) and tetraphenylbutadiene (TPB), gamma light yields with 15 wt% bismuth tripivalate of 5000 Ph/MeV are measured. A PVT plastic formulation including 30 wt% lithium pivalate and 30 wt% PPO offers both pulse shape discrimination, and a neutron capture peak at ~400 keVee. In another configuration, a bismuth-loaded PVT plastic is coated with ZnS(6Li) paint, permitting simultaneous gamma and neutron detection via pulse shape discrimination with a figure-of-merit of 3.8, while offering gamma spectroscopy with energy resolution of R(662 keV)=15%.

  3. Combined, solid-state molecular property and gamma spectrometers for CBRNE detection

    NASA Astrophysics Data System (ADS)

    Rogers, Ben; Grate, Jay; Pearson, Brett; Gallagher, Neal; Wise, Barry; Whitten, Ralph; Adams, Jesse

    2013-05-01

    Nevada Nanotech Systems, Inc. (Nevada Nano) has developed a multi-sensor solution to Chemical, Biological, Radiological, Nuclear and Explosives (CBRNE) detection that combines the Molecular Property Spectrometer™ (MPS™)—a micro-electro-mechanical chip-based technology capable of measuring a variety of thermodynamic and electrostatic molecular properties of sampled vapors and particles—and a compact, high-resolution, solid-state gamma spectrometer module for identifying radioactive materials, including isotopes used in dirty bombs and nuclear weapons. By conducting multiple measurements, the system can provide a more complete characterization of an unknown sample, leading to a more accurate identification. Positive identifications of threats are communicated using an integrated wireless module. Currently, system development is focused on detection of commercial, military and improvised explosives, radioactive materials, and chemical threats. The system can be configured for a variety of CBRNE applications, including handheld wands and swab-type threat detectors requiring short sample times, and ultra-high sensitivity detectors in which longer sampling times are used. Here we provide an overview of the system design and operation and present results from preliminary testing.

  4. SWEPP Gamma-Ray Spectrometer System software design description

    SciTech Connect

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

    1994-08-01

    To assist in the characterization of the radiological contents of contract-handled waste containers at the Stored Waste Examination Pilot Plant (SWEPP), the SWEPP Gamma-Ray Spectrometer (SGRS) System has been developed by the Radiation Measurements and Development Unit of the Idaho National Engineering Laboratory. The SGRS system software controls turntable and detector system activities. In addition to determining the concentrations of gamma-ray-emitting radionuclides, this software also calculates attenuation-corrected isotopic mass ratios of-specific interest. This document describes the software design for the data acquisition and analysis software associated with the SGRS system.

  5. An enhanced high-resolution EMCCD-based gamma camera using SiPM side detection.

    PubMed

    Heemskerk, J W T; Korevaar, M A N; Huizenga, J; Kreuger, R; Schaart, D R; Goorden, M C; Beekman, F J

    2010-11-21

    Electron-multiplying charge-coupled devices (EMCCDs) coupled to scintillation crystals can be used for high-resolution imaging of gamma rays in scintillation counting mode. However, the detection of false events as a result of EMCCD noise deteriorates the spatial and energy resolution of these gamma cameras and creates a detrimental background in the reconstructed image. In order to improve the performance of an EMCCD-based gamma camera with a monolithic scintillation crystal, arrays of silicon photon-multipliers (SiPMs) can be mounted on the sides of the crystal to detect escaping scintillation photons, which are otherwise neglected. This will provide a priori knowledge about the correct number and energies of gamma interactions that are to be detected in each CCD frame. This information can be used as an additional detection criterion, e.g. for the rejection of otherwise falsely detected events. The method was tested using a gamma camera based on a back-illuminated EMCCD, coupled to a 3 mm thick continuous CsI:Tl crystal. Twelve SiPMs have been mounted on the sides of the CsI:Tl crystal. When the information of the SiPMs is used to select scintillation events in the EMCCD image, the background level for (99m)Tc is reduced by a factor of 2. Furthermore, the SiPMs enable detection of (125)I scintillations. A hybrid SiPM-/EMCCD-based gamma camera thus offers great potential for applications such as in vivo imaging of gamma emitters. PMID:21030743

  6. Contraband detection using high-energy gamma rays from {sup 16}O*

    SciTech Connect

    Micklich, B.J.; Fink, C.L.; Sagalovsky, L.; Smith, D.L.

    1996-12-01

    High-energy monoenergetic gamma rays (6.13 and 7.12 MeV) from the decay of excited states of the {sup 16}O* nucleus are highly penetrating and thus offer potential for non-intrusive inspection of loaded containers for narcotics, explosives, and other contraband items. These excited states can be produced by irradiation of water with 14-MeV neutrons from a DT neutron generator or through the {sup 19}F(p,{alpha}){sup 16}O* reaction. Resonances in {sup 19}F(p,{alpha}){sup 16}O* at proton energies between 340 keV and 2 MeV allow use of a low-energy accelerator to provide a compact, portable gamma source of reasonable intensity. The present work provides estimates of gamma source parameters and suggests how various types of contraband could be detected. Gamma rays can be used to perform transmission or emission radiography of containers or other objects. Through the use of ({gamma}, n) and ({gamma}, fission) reactions, this technique is also capable of detecting special nuclear materials such as deuterium, lithium, beryllium, uranium, and plutonium. Analytic and Monte Carlo techniques are used to model empty and loaded container inspection for accelerator-produced gamma, radioisotope, and x-ray sources.

  7. Contraband detection using high-energy gamma rays from 16O*

    NASA Astrophysics Data System (ADS)

    Micklich, Bradley J.; Fink, Charles L.; Sagalovsky, Leonid; Smith, Donald L.

    1997-02-01

    High-energy monoenergetic gamma rays (6.13 and 7.12 MeV) from the decay of excited states of the 16O* nucleus are highly penetrating and thus offer potential for non- intrusive inspection of loaded containers for narcotics, explosives, and other contraband items. These excited states can be produced by irradiation of water with 14-MeV neutrons from a DT neutron generator or through the 19F(p,alpha)16O* reaction. Resonances in 19F(p,alpha)16O* at proton energies between 340 keV and 2 MeV allow use of a low-energy accelerator to provide a compact, portable gamma source of reasonable intensity. The present work provides estimates of gamma source parameters and suggests how various types of contraband could be detected. Gamma rays can be used to perform transmission or emission radiography of containers or other objects. Through the use of (gamma,n) and (gamma,fission) reactions, this technique is also capable of detecting special nuclear materials such as deuterium, lithium, beryllium, uranium, and plutonium. Analytic and Monte Carlo techniques are used to model empty and loaded container inspection for accelerator-produced gamma, radioisotope, and x-ray sources.

  8. 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). PMID:21129990

  9. ATel draft: Fermi LAT detection of a new Gamma-ray Source PKS 2247-131

    NASA Astrophysics Data System (ADS)

    Buson, S.

    2016-07-01

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

  10. Gadolinium-doped water cerenkov-based neutron and high energy gamma-ray detector and radiation portal monitoring system

    SciTech Connect

    Dazeley, Steven A; Svoboda, Robert C; Bernstein, Adam; Bowden, Nathaniel

    2013-02-12

    A water Cerenkov-based neutron and high energy gamma ray detector and radiation portal monitoring system using water doped with a Gadolinium (Gd)-based compound as the Cerenkov radiator. An optically opaque enclosure is provided surrounding a detection chamber filled with the Cerenkov radiator, and photomultipliers are optically connected to the detect Cerenkov radiation generated by the Cerenkov radiator from incident high energy gamma rays or gamma rays induced by neutron capture on the Gd of incident neutrons from a fission source. The PMT signals are then used to determine time correlations indicative of neutron multiplicity events characteristic of a fission source.

  11. Calibration of the RLS HPGe spectral gamma ray logging system

    SciTech Connect

    Koizumi, C.J.; Brodeur, J.R.; Ulbricht, W.H.; Price, R.K.

    1991-11-01

    Gamma-ray spectral data have been recorded with the Radionuclide Logging System (RLS) high purity germanium (HPGe) system at (1) the American Petroleum Institute (API) spectral gamma-ray calibration center in Houston, Texas; (2) the US Department of Energy (DOE) spectral gamma-ray field calibration facility in Spokane, Washington; and (3) the DOE spectral gamma-ray primary calibration center in Grand Junction, Colorado. Analyses of the Grand Junction data yielded: calibration constants for the natural gamma-ray sources (potassium, uranium and thorium), energy-dependent borehole diameter corrections for the aid-filled borehole, energy-dependent borehole casing corrections for steel casing over a range of thicknesses from 0 to 79 cm (5/16 in.), a casing index function that varies with casing thickness and provides a method for verifying that the correct casing correction is applied, and an energy-dependent inverse function that is the basis for assessment of subsurface concentrations of man-made gamma-ray emitters such as cesium-137 and cobalt-60.

  12. High Energy Electron and Gamma - Ray Detection with ATIC

    NASA Technical Reports Server (NTRS)

    Chang, J.; Schmidt, W. K. H.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The Advanced Thin Ionization Calorimeter (ATIC) balloon borne ionization calorimeter is well suited to record and identify high energy cosmic ray electrons, and at very high energies gamma-ray photons as well. We have simulated the performance of the instrument, and compare the simulations with actual high energy electron exposures at the CERN accelerator. Simulations and measurements do not compare exactly, in detail, but overall the simulations have predicted actual measured behavior quite well. ATIC has had its first 16 day balloon flight at the turn of the year over Antarctica, and first results obtained using the analysis methods derived from simulations and calibrations will be reported.

  13. Two Early Gamma-ray Bursts Optical Afterglow Detections with TAOS Telescopes--GRB 071010B and GRB 071112C

    SciTech Connect

    Huang, K. Y.; Wang, S. Y.; Urata, Y.

    2009-05-25

    We present on two early detections of GRB afterglows with the Taiwanese-American Occltation Sruvey (TAOS) telescopes. The robotic TAOS system has been devised so that the routine Kuiper Belt Object (KBO) survey is interrupted when a GRB alert is triggered. Our first detection, GRB 071010B was detected by TAOS 62 s after the burst and showed a weak early brightening during the observations. No significant correction with the prompt gamma-ray emission indicated that our optical emission detected is afterglow emission. The second detection of TAOS, GRB 071112C was detected 96 s after the burst, also showed a possible initial raising then followed a steep decay in the R-band light curve.

  14. Two Early Gamma-ray Bursts Optical Afterglow Detections with TAOS Telescopes-GRB 071010B and GRB 071112C

    NASA Astrophysics Data System (ADS)

    Huang, K. Y.; Wang, S. Y.; Urata, Y.

    2009-05-01

    We present on two early detections of GRB afterglows with the Taiwanese-American Occltation Sruvey (TAOS) telescopes. The robotic TAOS system has been devised so that the routine Kuiper Belt Object (KBO) survey is interrupted when a GRB alert is triggered. Our first detection, GRB 071010B was detected by TAOS 62 s after the burst and showed a weak early brightening during the observations. No significant correction with the prompt gamma-ray emission indicated that our optical emission detected is afterglow emission. The second detection of TAOS, GRB 071112C was detected 96 s after the burst, also showed a possible initial raising then followed a steep decay in the R-band light curve.

  15. Hand held explosives detection system

    DOEpatents

    Conrad, Frank J.

    1992-01-01

    The present invention is directed to a sensitive hand-held explosives detection device capable of detecting the presence of extremely low quantities of high explosives molecules, and which is applicable to sampling vapors from personnel, baggage, cargo, etc., as part of an explosives detection system.

  16. The UCR gamma ray telescope data acquisition system

    NASA Technical Reports Server (NTRS)

    O'Neill, T. J.; Sweeney, W. E.; Tumer, O. T.; Zych, A. D.; White, R. S.

    1988-01-01

    A description is given of an electronics system based on the DEC Falcon SBC-11/23+, which has been designed and built to support a balloon-borne double Compton gamma-ray telescope. The system provides support for commands, data acquisition, data routing and compression, and photomultiplier tube gain control. The software consists of a number of interrupt-driven routines of differing priorities to handle each system task. This includes two circular buffers for onboard processing and bit encoding before transmission of the information to the ground computer. Acquisition of gamma-ray events at rates above the 200-Hz telemetry constraint is easily achieved.

  17. Fermi-LAT Detection of Gravitational Lens Delayed Gamma-Ray Flares from Blazar B0218+357

    NASA Technical Reports Server (NTRS)

    Cheung, C. C.; Larsson, S.; Scargle, J. D.; Amin, M. A.; Blandford, R. D.; Bulmash, D.; Chiang, J.; Ciprini, S.; Corbet, R. D. H.; Falco, E. E.; Marshall, P. J.; Wood, D. L.; Ajello, M.; Bastieri, D.; Chekhtman, A.; D'Ammando, F.; Giroletti, M.; Grove, J. E.; Lott, B.; Ohja, R.; Orienti, M.; Perkins, J. S.; Razzano, M.; Smith, A. W.; Thompson, D. J.; Wood, K. S.

    2014-01-01

    Using data from the Fermi Large Area Telescope (LAT), we report the first clear gamma-ray measurement of a delay between flares from the gravitationally lensed images of a blazar. The delay was detected in B0218+357, a known double-image lensed system, during a period of enhanced gamma-ray activity with peak fluxes consistently observed to reach greater than 20-50 times its previous average flux. An auto-correlation function analysis identified a delay in the gamma-ray data of 11.46 plus or minus 0.16 days (1 sigma) that is approximately 1 day greater than previous radio measurements. Considering that it is beyond the capabilities of the LAT to spatially resolve the two images, we nevertheless decomposed individual sequences of superposing gamma-ray flares/delayed emissions. In three such approximately 8-10 day-long sequences within an approximately 4-month span, considering confusion due to overlapping flaring emission and flux measurement uncertainties, we found flux ratios consistent with approximately 1, thus systematically smaller than those from radio observations. During the first, best-defined flare, the delayed emission was detailed with a Fermi pointing, and we observed flux doubling timescales of approximately 3-6 hours implying as well extremely compact gamma-ray emitting regions.

  18. Six millisecond pulsars detected by the Fermi Large Area Telescope and the radio/gamma-ray connection of millisecond pulsars

    NASA Astrophysics Data System (ADS)

    Espinoza, C. M.; Guillemot, L.; Çelik, Ö.; Weltevrede, P.; Stappers, B. W.; Smith, D. A.; Kerr, M.; Zavlin, V. E.; Cognard, I.; Eatough, R. P.; Freire, P. C. C.; Janssen, G. H.; Camilo, F.; Desvignes, G.; Hewitt, J. W.; Hou, X.; Johnston, S.; Keith, M.; Kramer, M.; Lyne, A.; Manchester, R. N.; Ransom, S. M.; Ray, P. S.; Shannon, R.; Theureau, G.; Webb, N.

    2013-03-01

    We report on the discovery of gamma-ray pulsations from five millisecond pulsars (MSPs) using the Fermi Large Area Telescope (LAT) and timing ephemerides provided by various radio observatories. We also present confirmation of the gamma-ray pulsations from a sixth source, PSR J2051-0827. Five of these six MSPs are in binary systems: PSRs J1713+0747, J1741+1351, J1600-3053 and the two black widow binary pulsars PSRs J0610-2100 and J2051-0827. The only isolated MSP is the nearby PSR J1024-0719, which is also known to emit X-rays. We present X-ray observations in the direction of PSRs J1600-3053 and J2051-0827. While PSR J2051-0827 is firmly detected, we can only give upper limits for the X-ray flux of PSR J1600-3053. There are no dedicated X-ray observations available for the other three objects. The MSPs mentioned above, together with most of the MSPs detected by Fermi, are used to put together a sample of 30 gamma-ray MSPs. This sample is used to study the morphology and phase connection of radio and gamma-ray pulse profiles. We show that MSPs with pulsed gamma-ray emission which is phase-aligned with the radio emission present the steepest radio spectra and the largest magnetic fields at the light cylinder among all MSPs. Also, we observe a trend towards very low, or undetectable, radio linear polarization levels. These properties could be attributed to caustic radio emission produced at a range of different altitudes in the magnetosphere. We note that most of these characteristics are also observed in the Crab pulsar, the only other radio pulsar known to exhibit phase-aligned radio and gamma-ray emission.

  19. Antigen detection systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infectious agents or their constituent parts (antigens or nucleic acids) can be detected in fresh, frozen, or fixed tissue using a variety of direct or indirect assays. The assays can be modified to yield the greatest sensitivity and specificity but in most cases a particular methodology is chosen ...

  20. Antigen detection systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infectious agents or their constituent parts (antigens or nucleic acids) can be detected in fresh, frozen, or fixed tissues or other specimens, using a variety of direct or indirect assays. The assays can be modified to yield the greatest sensitivity and specificity but in most cases a particular m...

  1. A Gamma Memory Neural Network for System Identification

    NASA Technical Reports Server (NTRS)

    Motter, Mark A.; Principe, Jose C.

    1992-01-01

    A gamma neural network topology is investigated for a system identification application. A discrete gamma memory structure is used in the input layer, providing delayed values of both the control inputs and the network output to the input layer. The discrete gamma memory structure implements a tapped dispersive delay line, with the amount of dispersion regulated by a single, adaptable parameter. The network is trained using static back propagation, but captures significant features of the system dynamics. The system dynamics identified with the network are the Mach number dynamics of the 16 Foot Transonic Tunnel at NASA Langley Research Center, Hampton, Virginia. The training data spans an operating range of Mach numbers from 0.4 to 1.3.

  2. Design of OLED gamma correction system based on the LUT

    NASA Astrophysics Data System (ADS)

    Tai, Yonghang; Yun, Lijun; Shi, Junsheng; Chen, Zaiqing; Li, Qiong

    2011-11-01

    Gamma correction is an important processing in reproduce images information realizing of video source. In order to improve the image sharpness of the OLED micro-display, a Gamma correction system was established to compensate for the gray scale distortion of the micro-display which is caused by the difference between the optical and electrical characteristic property. Based on the North OLEiD Company's 0.5 inch OLED, We proposed a Gamma correction system to converts 8 bits input signal into 9 bits displayed on the OLED. It used Microchip as the MCU and the master of the I2C serial bus, Development of the hardware system measurement verified the correction of VGA and CVBS video input and the picture quality also apparently improved.

  3. Protein detection system

    DOEpatents

    Fruetel, Julie A.; Fiechtner, Gregory J.; Kliner, Dahv A. V.; McIlroy, Andrew

    2009-05-05

    The present embodiment describes a miniature, microfluidic, absorption-based sensor to detect proteins at sensitivities comparable to LIF but without the need for tagging. This instrument utilizes fiber-based evanescent-field cavity-ringdown spectroscopy, in combination with faceted prism microchannels. The combination of these techniques will increase the effective absorption path length by a factor of 10.sup.3 to 10.sup.4 (to .about.1-m), thereby providing unprecedented sensitivity using direct absorption. The coupling of high-sensitivity absorption with high-performance microfluidic separation will enable real-time sensing of biological agents in aqueous samples (including aerosol collector fluids) and will provide a general method with spectral fingerprint capability for detecting specific bio-agents.

  4. Implications of the VHE {gamma}-Ray Detection of 3C279

    SciTech Connect

    Boettcher, M.

    2008-12-24

    We present simultaneous optical (BVRI) and X-ray (RXTE PCA) data on the quasar 3C279 from the day of the recent VHE detection by MAGIC and discuss the implications of the snap-shot spectral energy distribution (SED) for leptonic jet models of blazars. A one-zone synchrotron-self-Compton origin of the SED up to VHE {gamma}-rays can be ruled out. The VHE emission could, in principle, be interpreted as Compton upscattering of external radiation (e.g., from the broad-line regions) in a one-zone leptonic model. However, such an interpretation would require either an unusually low magnetic field of B{approx}0.03 G, or (in order to achieve approximate equipartition between magnetic field at B{approx}0.25 G and relativistic electrons) an unrealistically high Doppler factor of {gamma}{approx}140. In addition, such a model fails to reproduce the observed X-ray flux. We therefore conclude that a simple one-zone, homogeneous leptonic jet model is not able to plausibly reproduce the SED of 3C279 including the recently detected VHE {gamma}-ray emission. This as well as the lag of correlated variability in the optical with the VHE {gamma}-ray emission suggests a multi-zone model in which the optical emission is produced in a different region than the VHE {gamma}-ray emission. Alternatively, also a hadronic origin of the VHE {gamma}-rays seems plausible.

  5. Detection of Gamma Rays with E greater than 300 GeV From Markarian 501

    NASA Technical Reports Server (NTRS)

    Quinn, J.; Connaughton, V.; Akerlof, C. W.; Biller, S.; Buckley, J.; Carter-Lewis, D. A.; Catanese, M.; Cawley, M. F.; Fegan, D. J.; Finley, J. P.

    1996-01-01

    The detection of gamma rays of energy greater than 300 GeV from the BL Lacertae object Mrk 501 demonstrates that extragalactic TeV emission is not unique to Mrk 421. During 66 hr of observations between 1995 March and July we measured an average flux of 8.1 +/- 1.4 x 10(exp -12) cm(exp -2)/s above 300 GeV, a flux that is only 20 percent of the average Mrk 421 flux. The new gamma-ray source has not been reported by the Compton Gamma Ray Observatory as an emitter of gamma rays at lower energies. There is evidence for variability on timescales of days.

  6. Extended performance gas Cherenkov detector for gamma-ray detection in high-energy density experiments.

    PubMed

    Herrmann, H W; Kim, Y H; Young, C S; Fatherley, V E; Lopez, F E; Oertel, J A; Malone, R M; Rubery, M S; Horsfield, C J; Stoeffl, W; Zylstra, A B; Shmayda, W T; Batha, S H

    2014-11-01

    A new Gas Cherenkov Detector (GCD) with low-energy threshold and high sensitivity, currently known as Super GCD (or GCD-3 at OMEGA), is being developed for use at the OMEGA Laser Facility and the National Ignition Facility (NIF). Super GCD is designed to be pressurized to ≤400 psi (absolute) and uses all metal seals to allow the use of fluorinated gases inside the target chamber. This will allow the gamma energy threshold to be run as low at 1.8 MeV with 400 psi (absolute) of C2F6, opening up a new portion of the gamma ray spectrum. Super GCD operating at 20 cm from TCC will be ∼400 × more efficient at detecting DT fusion gammas at 16.7 MeV than the Gamma Reaction History diagnostic at NIF (GRH-6m) when operated at their minimum thresholds. PMID:25430303

  7. Extended performance gas Cherenkov detector for gamma-ray detection in high-energy density experimentsa)

    NASA Astrophysics Data System (ADS)

    Herrmann, H. W.; Kim, Y. H.; Young, C. S.; Fatherley, V. E.; Lopez, F. E.; Oertel, J. A.; Malone, R. M.; Rubery, M. S.; Horsfield, C. J.; Stoeffl, W.; Zylstra, A. B.; Shmayda, W. T.; Batha, S. H.

    2014-11-01

    A new Gas Cherenkov Detector (GCD) with low-energy threshold and high sensitivity, currently known as Super GCD (or GCD-3 at OMEGA), is being developed for use at the OMEGA Laser Facility and the National Ignition Facility (NIF). Super GCD is designed to be pressurized to ≤400 psi (absolute) and uses all metal seals to allow the use of fluorinated gases inside the target chamber. This will allow the gamma energy threshold to be run as low at 1.8 MeV with 400 psi (absolute) of C2F6, opening up a new portion of the gamma ray spectrum. Super GCD operating at 20 cm from TCC will be ˜400 × more efficient at detecting DT fusion gammas at 16.7 MeV than the Gamma Reaction History diagnostic at NIF (GRH-6m) when operated at their minimum thresholds.

  8. Extended performance gas Cherenkov detector for gamma-ray detection in high-energy density experiments

    SciTech Connect

    Herrmann, H. W. Kim, Y. H.; Young, C. S.; Fatherley, V. E.; Lopez, F. E.; Oertel, J. A.; Batha, S. H.; Malone, R. M.; Rubery, M. S.; Horsfield, C. J.; Stoeffl, W.; Zylstra, A. B.; Shmayda, W. T.

    2014-11-15

    A new Gas Cherenkov Detector (GCD) with low-energy threshold and high sensitivity, currently known as Super GCD (or GCD-3 at OMEGA), is being developed for use at the OMEGA Laser Facility and the National Ignition Facility (NIF). Super GCD is designed to be pressurized to ≤400 psi (absolute) and uses all metal seals to allow the use of fluorinated gases inside the target chamber. This will allow the gamma energy threshold to be run as low at 1.8 MeV with 400 psi (absolute) of C{sub 2}F{sub 6}, opening up a new portion of the gamma ray spectrum. Super GCD operating at 20 cm from TCC will be ∼400 × more efficient at detecting DT fusion gammas at 16.7 MeV than the Gamma Reaction History diagnostic at NIF (GRH-6m) when operated at their minimum thresholds.

  9. A large-area gamma-ray imaging telescope system

    NASA Technical Reports Server (NTRS)

    Koch, D. G.

    1983-01-01

    The concept definition of using the External Tank (ET) of the Space Shuttle as the basis for constructing a large area gamma ray imaging telescope in space is detailed. The telescope will be used to locate and study cosmic sources of gamma rays of energy greater than 100 MeV. Both the telescope properties and the means whereby an ET is used for this purpose are described. A parallel is drawn between those systems that would be common to both a Space Station and this ET application. In addition, those systems necessary for support of the telescope can form the basis for using the ET as part of the Space Station. The major conclusions of this concept definition are that the ET is ideal for making into a gamma ray telescope, and that this telescope will provide a substantial increase in collecting area.

  10. TU-C-BRE-08: IMRT QA: Selecting Meaningful Gamma Criteria Based On Error Detection Sensitivity

    SciTech Connect

    Steers, J; Fraass, B

    2014-06-15

    Purpose: To develop a strategy for defining meaningful tolerance limits and studying the sensitivity of IMRT QA gamma criteria by inducing known errors in QA plans. Methods: IMRT QA measurements (ArcCHECK, Sun Nuclear) were compared to QA plan calculations with induced errors. Many (>24) gamma comparisons between data and calculations were performed for each of several kinds of cases and classes of induced error types with varying magnitudes (e.g. MU errors ranging from -10% to +10%), resulting in over 3,000 comparisons. Gamma passing rates for each error class and case were graphed against error magnitude to create error curves in order to represent the range of missed errors in routine IMRT QA using various gamma criteria. Results: This study demonstrates that random, case-specific, and systematic errors can be detected by the error curve analysis. Depending on location of the peak of the error curve (e.g., not centered about zero), 3%/3mm threshold=10% criteria may miss MU errors of up to 10% and random MLC errors of up to 5 mm. Additionally, using larger dose thresholds for specific devices may increase error sensitivity (for the same X%/Ymm criteria) by up to a factor of two. This analysis will allow clinics to select more meaningful gamma criteria based on QA device, treatment techniques, and acceptable error tolerances. Conclusion: We propose a strategy for selecting gamma parameters based on the sensitivity of gamma criteria and individual QA devices to induced calculation errors in QA plans. Our data suggest large errors may be missed using conventional gamma criteria and that using stricter criteria with an increased dose threshold may reduce the range of missed errors. This approach allows quantification of gamma criteria sensitivity and is straightforward to apply to other combinations of devices and treatment techniques.

  11. Early results utilizing high-energy fission product (gamma) rays to detect fissionable material in cargo

    SciTech Connect

    Slaughter, D R; Accatino, M R; Bernstein, A; Church, J A; Descalle, M A; Gosnell, T B; Hall, J M; Loshak, A; Manatt, D R; Mauger, G J; McDowell, M; Moore, T M; Norman, E B; Pohl, B A; Pruet, J A; Petersen, D C; Walling, R S; Weirup, D L; Prussin, S G

    2004-09-30

    A concept for detecting the presence of special nuclear material ({sup 235}U or {sup 239}Pu) concealed in intermodal cargo containers is described. It is based on interrogation with a pulsed beam of 7 MeV neutrons that produce fission events and their {beta}-delayed neutron emission or {beta}-delayed high-energy {gamma}-radiation between beam pulses provide the detection signature. Fission product {beta}-delayed {gamma}-rays above 3 MeV are nearly ten times more abundant than {beta}-delayed neutrons and are distinct from natural radioactivity and from nearly all of the induced activity in a normal cargo. Detector backgrounds and potential interferences with the fission signature radiation have been identified and quantified. An important goal in the US is the detection of nuclear weapons or special nuclear material (SNM) concealed in intermodal cargo containers. This must be done with high detection probability, low false alarm rates, and without impeding commerce, i.e. about one minute for an inspection. The concept for inspection has been described before and its components are now being evaluated. While normal radiations emitted from plutonium may allow its detection, the majority of {sup 235}U {gamma} ray emission is at 186 keV, is readily attenuated by cargo, and thus not a reliable detection signature for passive detection. Delayed neutron detection following a neutron or photon beam pulse has been used successfully to detect lightly or unshielded SNM targets. While delayed neutrons can be easily distinguished from beam neutrons they have relatively low yield in fission, approximately 0.008 per fission in {sup 239}Pu and 0.017 per fission in {sup 235}U, and are rapidly attenuated in hydrogenous materials making that technique unreliable when challenged by thick hydrogenous cargo overburden. They propose detection of {beta}-delayed high-energy {gamma} radiation as a more robust signature characteristic of SNM.

  12. Direct Detection of Exoplanet Host Star Companion Gamma Cep B Using CIAO at the 8-m Telescope Subaru

    NASA Astrophysics Data System (ADS)

    Schmidt, T.

    2007-06-01

    Gamma Cep is known as a single-lined spectroscopic triple system at a distance of 13.8 pc, composed of a K1 III-IV primary star with V= 3.2 mag, a stellar-mass companion in a 66-67 year orbit (Torres 2007) and a sub-stellar companion with mass times sin(i) = 1.7 Jupiter masses, that is most likely a planet (Hatzes et al. 2003). We used the Adaptive Optics camera CIAO at the Japanese 8m telescope Subaru on Mauna Kea, Hawaii, with the semi-transparent coronograph to block most of the light from the primary to be able to image Gamma Cep B directly. We could clearly detect Gamma Cep B and used a photometric standard to determine the magnitude of B after PSF subtraction of K = 7.3 +- 0.2 mag. With the data the orbit of the two stars could be refined and thus we were able to determine the dynamical masses of these two stars in the Gamma Cep system, namely 1.40 +- 0.12 solar masses for the primary and 0.409 +-0.018 solar masses for the secondary (consistent with a M4 dwarf) as well as a new minimum mass of the sub-stellar companion of mass times sin(i) = 1.60 +- 0.13 Jupiter masses.

  13. Prompt gamma and neutron detection in BNCT utilizing a CdTe detector.

    PubMed

    Winkler, Alexander; Koivunoro, Hanna; Reijonen, Vappu; Auterinen, Iiro; Savolainen, Sauli

    2015-12-01

    In this work, a novel sensor technology based on CdTe detectors was tested for prompt gamma and neutron detection using boronated targets in (epi)thermal neutron beam at FiR1 research reactor in Espoo, Finland. Dedicated neutron filter structures were omitted to enable simultaneous measurement of both gamma and neutron radiation at low reactor power (2.5 kW). Spectra were collected and analyzed in four different setups in order to study the feasibility of the detector to measure 478 keV prompt gamma photons released from the neutron capture reaction of boron-10. The detector proved to have the required sensitivity to detect and separate the signals from both boron neutron and cadmium neutron capture reactions, which makes it a promising candidate for monitoring the spatial and temporal development of in vivo boron distribution in boron neutron capture therapy. PMID:26249745

  14. Gamma Interferon Release Assays for Detection of Mycobacterium tuberculosis Infection

    PubMed Central

    Denkinger, Claudia M.; Kik, Sandra V.; Rangaka, Molebogeng X.; Zwerling, Alice; Oxlade, Olivia; Metcalfe, John Z.; Cattamanchi, Adithya; Dowdy, David W.; Dheda, Keertan; Banaei, Niaz

    2014-01-01

    SUMMARY Identification and treatment of latent tuberculosis infection (LTBI) can substantially reduce the risk of developing active disease. However, there is no diagnostic gold standard for LTBI. Two tests are available for identification of LTBI: the tuberculin skin test (TST) and the gamma interferon (IFN-γ) release assay (IGRA). Evidence suggests that both TST and IGRA are acceptable but imperfect tests. They represent indirect markers of Mycobacterium tuberculosis exposure and indicate a cellular immune response to M. tuberculosis. Neither test can accurately differentiate between LTBI and active TB, distinguish reactivation from reinfection, or resolve the various stages within the spectrum of M. tuberculosis infection. Both TST and IGRA have reduced sensitivity in immunocompromised patients and have low predictive value for progression to active TB. To maximize the positive predictive value of existing tests, LTBI screening should be reserved for those who are at sufficiently high risk of progressing to disease. Such high-risk individuals may be identifiable by using multivariable risk prediction models that incorporate test results with risk factors and using serial testing to resolve underlying phenotypes. In the longer term, basic research is necessary to identify highly predictive biomarkers. PMID:24396134

  15. Thermal neutron detection system

    DOEpatents

    Peurrung, Anthony J.; Stromswold, David C.

    2000-01-01

    According to the present invention, a system for measuring a thermal neutron emission from a neutron source, has a reflector/moderator proximate the neutron source that reflects and moderates neutrons from the neutron source. The reflector/moderator further directs thermal neutrons toward an unmoderated thermal neutron detector.

  16. The Advanced Gamma-ray Imaging System (AGIS) - Simulation Studies

    SciTech Connect

    Maier, G.; Buckley, J.; Bugaev, V.; Fegan, S.; Vassiliev, V. V.; Funk, S.; Konopelko, A.

    2008-12-24

    The Advanced Gamma-ray Imaging System (AGIS) is a US-led concept for a next-generation instrument in ground-based very-high-energy gamma-ray astronomy. The most important design requirement for AGIS is a sensitivity of about 10 times greater than current observatories like Veritas, H.E.S.S or MAGIC. We present results of simulation studies of various possible designs for AGIS. The primary characteristics of the array performance, collecting area, angular resolution, background rejection, and sensitivity are discussed.

  17. Mini gamma camera, camera system and method of use

    DOEpatents

    Majewski, Stanislaw; Weisenberger, Andrew G.; Wojcik, Randolph F.

    2001-01-01

    A gamma camera comprising essentially and in order from the front outer or gamma ray impinging surface: 1) a collimator, 2) a scintillator layer, 3) a light guide, 4) an array of position sensitive, high resolution photomultiplier tubes, and 5) printed circuitry for receipt of the output of the photomultipliers. There is also described, a system wherein the output supplied by the high resolution, position sensitive photomultipiler tubes is communicated to: a) a digitizer and b) a computer where it is processed using advanced image processing techniques and a specific algorithm to calculate the center of gravity of any abnormality observed during imaging, and c) optional image display and telecommunications ports.

  18. An EAS experiment at mountain altitude for the detection of gamma-ray sources

    NASA Technical Reports Server (NTRS)

    Allkofer, O. C.; Samorski, M.; Stamm, W.

    1985-01-01

    The plan of an extensive air shower experiment 2.200 m above sea level for the detection of 10 to the 14th power eV to 10 to the 17th power eV gamma rays from sources in the declination band 0 deg to + 60 deg is described. The site selection, detector array and electronic layout are detailed.

  19. Renewed gamma-ray activity of the Blazar 3C 454.3 detected by AGILE

    NASA Astrophysics Data System (ADS)

    Bulgarelli, A.; Parmiggiani, N.; Fioretti, V.; Zoli, A.; Lucarelli, F.; Verrecchia, F.; Pittori, C.; Vercellone, S.; Piano, G.; Munar-Adrover, P.; Tavani, M.; Donnarumma, I.; Striani, E.; Cardillo, M.; Gianotti, F.; Trifoglio, M.; Giuliani, A.; Mereghetti, S.; Caraveo, P.; Perotti, F.; Chen, A.; Argan, A.; Costa, E.; Del Monte, E.; Evangelista, Y.; Feroci, M.; Lazzarotto, F.; Lapshov, I.; Pacciani, L.; Soffitta, P.; Sabatini, S.; Vittorini, V.; Pucella, G.; Rapisarda, M.; Di Cocco, G.; Fuschino, F.; Galli, M.; Labanti, C.; Marisaldi, M.; Pellizzoni, A.; Pilia, M.; Trois, A.; Barbiellini, G.; Vallazza, E.; Longo, F.; Morselli, A.; Picozza, P.; Prest, M.; Lipari, P.; Zanello, D.; Cattaneo, P. W.; Rappoldi, A.; Colafrancesco, S.; Ferrari, A.; Antonelli, A.; Giommi, P.; Salotti, L.; Valentini, G.; D'Amico, F.

    2016-06-01

    The AGILE satellite is detecting a significant enhancement in gamma-ray activity from the FSRQ 3C 454.3 (known as 1AGLR J2254+1609) since the recent AGILE ATel #9157, and the optical activity reported in ATel #9150.

  20. Power line detection system

    DOEpatents

    Latorre, Victor R.; Watwood, Donald B.

    1994-01-01

    A short-range, radio frequency (RF) transmitting-receiving system that provides both visual and audio warnings to the pilot of a helicopter or light aircraft of an up-coming power transmission line complex. Small, milliwatt-level narrowband transmitters, powered by the transmission line itself, are installed on top of selected transmission line support towers or within existing warning balls, and provide a continuous RF signal to approaching aircraft. The on-board receiver can be either a separate unit or a portion of the existing avionics, and can also share an existing antenna with another airborne system. Upon receipt of a warning signal, the receiver will trigger a visual and an audio alarm to alert the pilot to the potential power line hazard.

  1. Power line detection system

    DOEpatents

    Latorre, V.R.; Watwood, D.B.

    1994-09-27

    A short-range, radio frequency (RF) transmitting-receiving system that provides both visual and audio warnings to the pilot of a helicopter or light aircraft of an up-coming power transmission line complex. Small, milliwatt-level narrowband transmitters, powered by the transmission line itself, are installed on top of selected transmission line support towers or within existing warning balls, and provide a continuous RF signal to approaching aircraft. The on-board receiver can be either a separate unit or a portion of the existing avionics, and can also share an existing antenna with another airborne system. Upon receipt of a warning signal, the receiver will trigger a visual and an audio alarm to alert the pilot to the potential power line hazard. 4 figs.

  2. Centrifugal unbalance detection system

    DOEpatents

    Cordaro, Joseph V.; Reeves, George; Mets, Michael

    2002-01-01

    A system consisting of an accelerometer sensor attached to a centrifuge enclosure for sensing vibrations and outputting a signal in the form of a sine wave with an amplitude and frequency that is passed through a pre-amp to convert it to a voltage signal, a low pass filter for removing extraneous noise, an A/D converter and a processor and algorithm for operating on the signal, whereby the algorithm interprets the amplitude and frequency associated with the signal and once an amplitude threshold has been exceeded the algorithm begins to count cycles during a predetermined time period and if a given number of complete cycles exceeds the frequency threshold during the predetermined time period, the system shuts down the centrifuge.

  3. Radiation detection system

    DOEpatents

    Whited, R.C.

    A system for obtaining improved resolution in relatively thick semiconductor radiation detectors, such as HgI/sub 2/, which exhibit significant hole trapping. Two amplifiers are used: the first measures the charge collected and the second the contribution of the electrons to the charge collected. The outputs of the two amplifiers are utilized to unfold the total charge generated within the detector in response to a radiation event.

  4. NRF Based Nondestructive Inspection System for SNM by Using Laser-Compton-Backscattering Gamma-Rays

    NASA Astrophysics Data System (ADS)

    Ohgaki, H.; Omer, M.; Negm, H.; Daito, I.; Zen, H.; Kii, T.; Masuda, K.; Hori, T.; Hajima, R.; Hayakawa, T.; Shizuma, T.; Kando, M.

    2015-10-01

    A non-destructive inspection system for special nuclear materials (SNMs) hidden in a sea cargo has been developed. The system consists of a fast screening system using neutron generated by inertial electrostatic confinement (IEC) device and an isotope identification system using nuclear resonance fluorescence (NRF) measurements with laser Compton backscattering (LCS) gamma-rays has been developed. The neutron flux of 108 n/sec has been achieved by the IEC in static mode. We have developed a modified neutron reactor noise analysis method to detect fission neutron in a short time. The LCS gamma-rays has been generated by using a small racetrack microtoron accelerator and an intense sub-nano second laser colliding head-on to the electron beam. The gamma-ray flux has been achieved more than 105 photons/s. The NRF gamma-rays will be measured using LaBr3(Ce) scintillation detector array whose performance has been measured by NRF experiment of U-235 in HIGS facility. The whole inspection system has been designed to satisfy a demand from the sea port.

  5. APDS: Autonomous Pathogen Detection System

    SciTech Connect

    Langlois, R G; Brown, S; Burris, L; Colston, B; Jones, L; Makarewicz, T; Mariella, R; Masquelier, D; McBride, M; Milanovich, F; Masarabadi, S; Venkateswaran, K; Marshall, G; Olson, D; Wolcott, D

    2002-02-14

    An early warning system to counter bioterrorism, the Autonomous Pathogen Detection System (APDS) continuously monitors the environment for the presence of biological pathogens (e.g., anthrax) and once detected, it sounds an alarm much like a smoke detector warns of a fire. Long before September 11, 2001, this system was being developed to protect domestic venues and events including performing arts centers, mass transit systems, major sporting and entertainment events, and other high profile situations in which the public is at risk of becoming a target of bioterrorist attacks. Customizing off-the-shelf components and developing new components, a multidisciplinary team developed APDS, a stand-alone system for rapid, continuous monitoring of multiple airborne biological threat agents in the environment. The completely automated APDS samples the air, prepares fluid samples in-line, and performs two orthogonal tests: immunoassay and nucleic acid detection. When compared to competing technologies, APDS is unprecedented in terms of flexibility and system performance.

  6. Diversified transmission multichannel detection system

    SciTech Connect

    Tournois, P.; Engelhard, P.

    1984-07-03

    A detection system for imaging by sonar or radar signals. The system associates diversified transmissions with an interferometric base. This base provides an angular channel formation means and each signal formed in this way is processed by matched filtering in a circuit containing copy signals characterizing the space coloring obtained by the diversified transmission means. The invention is particularly applicable to side or front looking detection sonars.

  7. A gamma-ray verification system for special nuclear material

    SciTech Connect

    Lanier, R.G.; Prindle, A.L.; Friensehner, A.V.; Buckley, W.M.

    1994-07-01

    The Safeguards Technology Program at the Lawrence Livermore National Laboratory (LLNL) has developed a gamma-ray screening system for use by the Materials Management Section of the Engineering Sciences Division at LLNL for verifying the presence or absence of special nuclear material (SNM) in a sample. This system facilitates the measurements required under the ``5610`` series of US Department of Energy orders. MMGAM is an intelligent, menu driven software application that runs on a personal computer and requires a precalibrated multi-channel analyzer and HPGe detector. It provides a very quick and easy-to-use means of determining the presence of SNM in a sample. After guiding the operator through a menu driven set-up procedure, the system provides an on-screen GO/NO-GO indication after determining the system calibration status. This system represents advances over earlier used systems in the areas of ease-of use, operator training requirements, and quality assurance. The system records the gamma radiation from a sample using a sequence of measurements involving a background measurement followed immediately by a measurement of the unknown sample. Both spectra are stored and available for analysis or output. In the current application, the presence of {sup 235}U, {sup 238}U, {sup 239}Pu, and {sup 208}Tl isotopes are indicated by extracting, from the stored spectra, four energy ``windows`` preset around gamma-ray lines characteristic of the radioactive decay of these nuclides. The system is easily extendible to more complicated problems.

  8. Sensitive detection of Bacillus anthracis using a binding protein originating from gamma-phage.

    PubMed

    Fujinami, Yoshihito; Hirai, Yoshikazu; Sakai, Ikuko; Yoshino, Mineo; Yasuda, Jiro

    2007-01-01

    Detection of biological weapons is a primary concern in force protection, treaty verification, and safeguarding civilian populations against domestic terrorism. One great concern is the detection of Bacillus anthracis, the causative agent of anthrax. Therefore, there is a pressing need to develop novel methods for rapid, simple, and precise detection of B. anthracis. Here, we report that the C-terminal region of gamma-phage lysin protein (PlyG) binds specifically to the cell wall of B. anthracis and the recombinant protein corresponding to this region (positions, 156-233), PlyGB, is available as a bioprobe for detection of B. anthracis. Our detection method, based on a membrane direct blot assay using recombinant PlyGB, was more rapid and sensitive than the gamma-phage test and was simpler and more inexpensive than genetic methods such as PCR, or immunological methods using specific antibodies. Furthermore, its specificity was comparable to the gamma-phage test. PlyGB is applicable in conventional methods instead of antibodies and could be a potent tool for detection of B. anthracis. PMID:17310083

  9. Variability of Point Sources of Gamma Rays Detected by the Fermi Large-Area Telescope

    NASA Astrophysics Data System (ADS)

    Wallace, Eric

    The Large Area Telescope (LAT) aboard the Fermi Gamma-Ray Space Telescope has revolutionized gamma-ray astronomy, allowing the detection of thousands of point sources of gamma rays. Variability studies are of significant interest as a potential source of information about the emission mechanisms, and as a means to identify gamma-ray sources with known sources in other wavelengths and to improve detection sensitivity in searches for new sources. The inclusion of temporal resolution, however, adds to the already considerable complexity of the required analysis, and as a result, variability studies have generally been limited either in scope or in detail, or both, compared to time-integrated spectral analyses. pointlike is a software package designed for fast maximum likelihood analysis of LAT data, allowing for interactive and large-scale analyses. Here, we present an application of pointlike to the characterization of the variability of the full sample of known gamma-ray point sources. We describe the construction of light curves in one-month time bins, spanning the first 42 months of the Fermi mission, for a sample of 2652 sources. We discuss the use of the detection significance in individual months to improve the significance of detection of marginal sources, and show that including that measure of significance increases the set of significantly detected sources by nearly 20% compared to using only the average significance. We describe a statistical measure of the significance of variability in a light curve, and examine the variability of thesample as whole, and of subsets associated with particular source types, especially pulsars. We discuss the use of pulsars, which are generally non-variable on long timescales, to calibrate variability statistics, and to assess the importance of systematic errors in estimates of variability. Finally, we discuss the potential to extend the method to produce light curves of longer duration and finer time binning, and to search

  10. Testing of a gamma ray imaging system at Omega

    NASA Astrophysics Data System (ADS)

    Lemieux, Daniel A.; Barber, H. Bradford; Grim, Gary P.; Clark, David D.; Danly, Christopher R.; Aragonez, Robert; Griego, Jeffrey; Fatherley, Valerie; Fastje, Daivd

    2013-09-01

    Successful images of hard x-rays were taken at the OMEGA Laser at the Laboratory for Laser energetics ant he University of Rochester. This facility served as a surrogate for the National Ignition Facility for which this system was designed. Eleven plastic shells filled with 3He pellets were imploded producing soft and hard x-rays. As the system was designed to image 4.44MeV gammas the hard x-rays were of particular interest. These bremsstrahlung x-rays were emitted for the outer plastic shell and imaged using the gamma ray imaging system 13 meters away. A number of filtering arrangements were used to do transmission radiography of the source providing spectrum information. A 200-micron pinhole aperture was used to image the source. These shots provide information critical in characterizing the performance of the system

  11. Radial Electron Temperature and Density Measurements Using Thomson Scattering System in GAMMA 10/PDX

    NASA Astrophysics Data System (ADS)

    Yoshikawa, M.; Ohta, K.; Wang, X.; Chikatsu, M.; Kohagura, J.; Shima, Y.; Sakamoto, M.; Imai, T.; Nakashima, Y.; Yasuhara, R.; Yamada, I.; Funaba, H.; Minami, T.

    2015-11-01

    A Thomson scattering (TS) system in GAMMA 10/PDX has been developed for the measurement of radial profiles of electron temperature and density in a single plasma and laser shot. The TS system has a large solid angle optical collection system and high-sensitivity signal detection system. The TS signals are obtained using four-channel high-speed digital oscilloscopes controlled by a Windows PC. We designed the acquisition program for six oscilloscopes to obtain 10-Hz TS signals in a single plasma shot, following which the time-dependent electron temperatures and densities can be determined. Moreover, in order to obtain larger TS signal intensity in the edge region, we added a second collection mirror. The radial electron temperatures and densities at six radial positions in GAMMA 10/PDX were successfully obtained.

  12. CdMnTe in X-ray and Gamma-ray Detection: Potential Applications

    SciTech Connect

    Cui,Y.; Bolotnikov, A.; Hossain, A.; Camarda, G.; Mycielski, A.; Yang, G.; Kochanowska, D.; Witkowska-Baran, M.; James, R.B.

    2008-08-11

    CdMnTe can be a good candidate for gamma-ray detection because of its wide band-gap, high resistivity, and good electro-transport properties. Further, the ability to grow CMT crystals at relatively low temperatures ensures a high yield for manufacturing detectors with good compositional uniformity and few impurities. Our group at Brookhaven National Laboratory is investigating several CMT crystals, selecting a few of them to make detectors. In this paper, we discuss our initial characterization of these crystals and describe our preliminary results with a gamma-ray source.

  13. Fermi Detection of a Luminous gamma-ray Pulsar in a Globular Cluster

    NASA Technical Reports Server (NTRS)

    Freire, P. C. C.; Abdo, A. A.; Ajello, M.; Allafort, A.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Celik, O.; Ferrara, E. C.; Gehrels, N.; Harding, A.; Johnson, T. J.; McEnery, J. E.; Thompson, D. J.; Troja, E.

    2011-01-01

    We report the Fermi Large Area Telescope detection of gamma -ray (>100 mega-electron volts) pulsations from pulsar J1823--3021A in the globular cluster NGC 6624 with high significance (approx 7 sigma). Its gamma-ray luminosity L (sub 3) = (8:4 +/- 1:6) X 10(exp 34) ergs per second, is the highest observed for any millisecond pulsar (MSP) to date, and it accounts for most of the cluster emission. The non-detection of the cluster in the off-pulse phase implies that its contains < 32 gamma-ray MSPs, not approx 100 as previously estimated. The gamma -ray luminosity indicates that the unusually large rate of change of its period is caused by its intrinsic spin-down. This implies that J1823--3021A has the largest magnetic field and is the youngest MSP ever detected, and that such anomalous objects might be forming at rates comparable to those of the more normal MSPs.

  14. Challenges in detecting gamma-rays from dark matter annihilations in the galactic center

    SciTech Connect

    Zaharijas, Gabrijela; Hooper, Dan

    2006-05-15

    Atmospheric Cerenkov Telescopes, including HESS and MAGIC, have detected a spectrum of gamma-rays from the galactic center region which extends from {approx}200 GeV or lower, to at least {approx}10 TeV. Although the source of this radiation is not yet known, the spectrum appears to behave as a simple power-law, which is not the expectation for gamma-rays generated through the annihilation of dark matter particles. If instead we conclude that the source of these gamma-rays is astrophysical in origin, this spectrum will constitute a background for future dark matter searches using gamma-rays from this region. In this paper we study how this background will affect the prospects for experiments such as GLAST to detect dark matter in the galactic center. We find that only a narrow range of dark matter annihilation rates are potentially observable by GLAST given this newly discovered background and considering current constraints from EGRET and HESS. We also find that a detection of line emission, while not completely ruled out, is only possible for a very narrow range of dark matter models and halo profiles.

  15. AGN Detection Ranges of MACE and TACTIC Imaging Gamma-Ray Telescopes

    NASA Astrophysics Data System (ADS)

    Kaul, C. L.; Shanthi, K.; Bhat, C. L.; Tickoo, A. K.; Kaul, R. K.

    Two high-sensitivity imaging gamma-ray telescopes, MACE and TACTIC, are being set up at Mt. Abu, India, for making detailed spectral and temporal investigations of galactic and extragalactic gamma-ray sources in the photon energy bands. Egamma ~ 20-200 GeV and ~ 0.5-5TeV respectively. Here, we estimate the effective red-shift ranges of these telescopes for detecting gamma-ray signals from the EGRET-detected AGN's and identify the most likely candidate-sources for detection by the MACE and the TACTIC, under the assumption that the EGRET-inferred power-law spectra for these AGN's extend into the GeV-TeV range without any change in shape. Extremum bounds of the relevant intergalactic background radiation fields, suggested by various observational and theoretical considerations, have been used to estimate the attenuation of VHE gamma-ray fluxes due to photon-photon pair-production process, leading to the desired z-ranges for these instruments.

  16. Characterization of mobile radiation detection systems at the Hanford Site

    SciTech Connect

    Antonio, E.J.; Schmidt, J.W.; Gunnink, D.S.; Nelsen, L.A.

    1993-01-01

    The use of vehicle-mounted radiation detection systems for characterizing large areas contaminated with radioactive materials at the Hanford Reservation were examined. Detection capabilities as a function of vehicle speed, detector-source geometry, and source characteristics were evaluated for each of the three systems currently used at the Hanford Site. Large-area radioactive sources (1 ft{sup 2}) with varying source strengths containing gamma- and beta-emitting radionuclides were used to measure detection-system performance. Detection capability was found to be most influenced by vehicle speed and detector-source geometry. As the vehicle`s speed was increased, the probability of detecting a given source decreased dramatically. The probability of detecting a given source was significantly lower under ``poor`` geometry conditions. Each vehicle`s monitoring performance was found to compare favorably with portable survey instrument capabilities. The use of vehicle-mounted detectors proves to be far more economical for surveying large surface areas.

  17. Gamma Band Activity in the Reticular Activating System

    PubMed Central

    Urbano, Francisco J.; Kezunovic, Nebojsa; Hyde, James; Simon, Christen; Beck, Paige; Garcia-Rill, Edgar

    2012-01-01

    This review considers recent evidence showing that cells in three regions of the reticular activating system (RAS) exhibit gamma band activity, and describes the mechanisms behind such manifestation. Specifically, we discuss how cells in the mesopontine pedunculopontine nucleus (PPN), intralaminar parafascicular nucleus (Pf), and pontine subcoeruleus nucleus dorsalis (SubCD) all fire in the beta/gamma band range when maximally activated, but no higher. The mechanisms behind this ceiling effect have been recently elucidated. We describe recent findings showing that every cell in the PPN have high-threshold, voltage-dependent P/Q-type calcium channels that are essential, while N-type calcium channels are permissive, to gamma band activity. Every cell in the Pf also showed that P/Q-type and N-type calcium channels are responsible for this activity. On the other hand, every SubCD cell exhibited sodium-dependent subthreshold oscillations. A novel mechanism for sleep–wake control based on well-known transmitter interactions, electrical coupling, and gamma band activity is described. The data presented here on inherent gamma band activity demonstrates the global nature of sleep–wake oscillation that is orchestrated by brainstem–thalamic mechanism, and questions the undue importance given to the hypothalamus for regulation of sleep–wakefulness. The discovery of gamma band activity in the RAS follows recent reports of such activity in other subcortical regions like the hippocampus and cerebellum. We hypothesize that, rather than participating in the temporal binding of sensory events as seen in the cortex, gamma band activity manifested in the RAS may help stabilize coherence related to arousal, providing a stable activation state during waking and paradoxical sleep. Most of our thoughts and actions are driven by pre-conscious processes. We speculate that continuous sensory input will induce gamma band activity in the RAS that could participate in the processes of

  18. Sensitivity of {gamma}-ray telescopes for detection of magnetic fields in the intergalactic medium

    SciTech Connect

    Neronov, A.; Semikoz, D. V.

    2009-12-15

    We explore potential of current and next-generation {gamma}-ray telescopes for the detection of weak magnetic fields in the intergalactic medium. We demonstrate that using two complementary techniques, observation of extended emission around point sources and observation of time delays in {gamma}-ray flares, one would be able to probe most of the cosmologically and astrophysically interesting part of the 'magnetic field strength' vs 'correlation length' parameter space. This implies that {gamma}-ray observations with Fermi and ground-based Cherenkov telescopes will allow to (a) strongly constrain theories of the origin of magnetic fields in galaxies and galaxy clusters and (b) discover, constrain or rule out the existence of weak primordial magnetic field generated at different stages of evolution of the Early Universe.

  19. Detection of gamma-ray emission from the Vela pulsar wind nebula with AGILE.

    PubMed

    Pellizzoni, A; Trois, A; Tavani, M; Pilia, M; Giuliani, A; Pucella, G; Esposito, P; Sabatini, S; Piano, G; Argan, A; Barbiellini, G; Bulgarelli, A; Burgay, M; Caraveo, P; Cattaneo, P W; Chen, A W; Cocco, V; Contessi, T; Costa, E; D'Ammando, F; Del Monte, E; De Paris, G; Di Cocco, G; Di Persio, G; Donnarumma, I; Evangelista, Y; Feroci, M; Ferrari, A; Fiorini, M; Fuschino, F; Galli, M; Gianotti, F; Hotan, A; Labanti, C; Lapshov, I; Lazzarotto, F; Lipari, P; Longo, F; Marisaldi, M; Mastropietro, M; Mereghetti, S; Moretti, E; Morselli, A; Pacciani, L; Palfreyman, J; Perotti, F; Picozza, P; Pittori, C; Possenti, A; Prest, M; Rapisarda, M; Rappoldi, A; Rossi, E; Rubini, A; Santolamazza, P; Scalise, E; Soffitta, P; Striani, E; Trifoglio, M; Vallazza, E; Vercellone, S; Verrecchia, F; Vittorini, V; Zambra, A; Zanello, D; Giommi, P; Colafrancesco, S; Antonelli, A; Salotti, L; D'Amico, N; Bignami, G F

    2010-02-01

    Pulsars are known to power winds of relativistic particles that can produce bright nebulae by interacting with the surrounding medium. These pulsar wind nebulae are observed by their radio, optical, and x-ray emissions, and in some cases also at TeV (teraelectron volt) energies, but the lack of information in the gamma-ray band precludes drawing a comprehensive multiwavelength picture of their phenomenology and emission mechanisms. Using data from the AGILE satellite, we detected the Vela pulsar wind nebula in the energy range from 100 MeV to 3 GeV. This result constrains the particle population responsible for the GeV emission and establishes a class of gamma-ray emitters that could account for a fraction of the unidentified galactic gamma-ray sources. PMID:20044540

  20. Detection and measurement of gamma-ray self-attenuation in plutonium residues

    SciTech Connect

    Prettyman, T.H.; Foster, L.A.; Estep, R.J.

    1996-09-01

    A new method to correct for self-attenuation in gamma-ray assays of plutonium is presented. The underlying assumptions of the technique are based on a simple but accurate physical model of plutonium residues, particularly pyrochemical salts, in which it is assumed that the plutonium is divided into two portions, each of which can be treated separately from the standpoint of gamma-ray analysis: a portion that is in the form of plutonium metal shot; and a dilute portion that is mixed with the matrix. The performance of the technique is evaluated using assays of plutonium residues by tomographic gamma scanning at the Los Alamos Plutonium Facility. The ability of the method to detect saturation conditions is examined.

  1. DETECTION OF VHE {gamma}-RAYS FROM HESS J0632+057 DURING THE 2011 FEBRUARY X-RAY OUTBURST WITH THE MAGIC TELESCOPES

    SciTech Connect

    Aleksic, J.; Blanch, O.; Alvarez, E. A.; Asensio, M.; Barrio, J. A.; Antonelli, L. A.; Bonnoli, G.; Antoranz, P.; Backes, M.; Barres de Almeida, U.; Bock, R. K.; Borla Tridon, D.; Bastieri, D.; Becerra Gonzalez, J.; Berger, K.; Bednarek, W.; Bernardini, E.; Biland, A.; Boller, A.; Bosch-Ramon, V. E-mail: pmunar@am.ub.es; and others

    2012-07-20

    The very high energy (VHE) {gamma}-ray source HESS J0632+057 has recently been confirmed to be a {gamma}-ray binary. The optical counterpart is the Be star MWC 148, and a compact object of unknown nature orbits it every {approx}321 days with a high eccentricity of {approx}0.8. We monitored HESS J0632+057 with the stereoscopic MAGIC telescopes from 2010 October to 2011 March and detected significant VHE {gamma}-ray emission during 2011 February, when the system exhibited an X-ray outburst. We find no {gamma}-ray signal in the other observation periods when the system did not show increased X-ray flux. Thus, HESS J0632+057 exhibits {gamma}-ray variability on timescales of the order of one to two months possibly linked to the X-ray outburst that takes place about 100 days after the periastron passage. Furthermore, our measurements provide for the first time the {gamma}-ray spectrum down to about 140 GeV and indicate no turnover of the spectrum at low energies. We compare the properties of HESS J0632+057 with the similar {gamma}-ray binary LS I +61 Degree-Sign 303 and discuss the possible origin of the multi-wavelength emission of the source.

  2. Swift-BAT: The First Year of Gamma-Ray Burst Detections

    NASA Technical Reports Server (NTRS)

    Krimm, Hans A.

    2006-01-01

    The Burst Alert Telescope (BAT) on the Swift has been detecting gamma-ray bursts (GRBs) since Dec. 17,2004 and automated burst alerts have been distributed since Feb. 14,2005. Since commissioning the BAT has triggered on more than 100 GRBs, nearly all of which have been followed up by the narrow-field instruments on Swift through automatic repointing, and by ground and other satellite telescopes after rapid notification. Within seconds of a trigger the BAT produces and relays to the ground a position good to three arc minutes and a four channel light curve. A full ten minutes of event data follows on subsequent ground station passes. The burst archive has allowed us to determine ensemble burst parameters such as fluence, peak flux and duration. An overview of the properties of BAT bursts and BAT'S performance as a burst monitor will be presented in this talk. BAT is a coded aperture imaging system with a wide (approx.2 sr) field of view consisting of a large coded mask located 1 m above a 5200 cm2 array of 32.768 CdZnTe detectors. All electronics and other hardware systems on the BAT have been operating well since commissioning and there is no sign of any degradation on orbit. The flight and ground software have proven similarly robust and allow the real time localization of all bursts and the rapid derivation of burst light curves, spectra and spectral fits on the ground.

  3. Detection of the Crab Nebula By UV Imaging of TeV Gamma Ray Air Showers

    NASA Astrophysics Data System (ADS)

    Chantell, M.

    1994-12-01

    With successful detection of TeV gamma ray fluxes from the Crab Nebula and the AGN, MRK421, the Whipple Observatory Gamma Ray Collaboration has demonstrated the sensitivity of the Cherenkov imaging technique in ground-based gamma-ray astronomy. This technique uses an array of 109 blue-sensitive photomultipliers to image the Cherenkov radiation produced when TeV gamma and cosmic rays enter the earth's atmosphere. One major limitation of this technique is the requirement of absolutely dark skies during observations. The presence of the moon rules out the possibility of making observations because of the high sensitivity of the photomultipliers used in the camera. To address this limitation we have developed a camera which utilizes solar-blind photomultpliers with primary sensitivity from 220nm to 280nm allowing observations even in the presence of the full moon. After two years of UV observations of the Crab Nebula we have demonstrated the ability to discriminate gamma rays from the hadronic background with an energy threshold of approximately 1 TeV. The development of this camera makes it possible to increase the duty cycle of the 10 meter telescope allowing observations in bright time. Additionally the insensitivity to background star light allows this camera to observe sources in bright regions of the galactic plane, where high background light levels have limited the usefulness of the visible camera.

  4. A simultaneous beta and coincidence-gamma imaging system for plant leaves.

    PubMed

    Ranjbar, Homayoon; Wen, Jie; Mathews, Aswin J; Komarov, Sergey; Wang, Qiang; Li, Ke; O'Sullivan, Joseph A; Tai, Yuan-Chuan

    2016-05-01

    Positron emitting isotopes, such as (11)C, (13)N, and (18)F, can be used to label molecules. The tracers, such as (11)CO2, are delivered to plants to study their biological processes, particularly metabolism and photosynthesis, which may contribute to the development of plants that have a higher yield of crops and biomass. Measurements and resulting images from PET scanners are not quantitative in young plant structures or in plant leaves due to poor positron annihilation in thin objects. To address this problem we have designed, assembled, modeled, and tested a nuclear imaging system (simultaneous beta-gamma imager). The imager can simultaneously detect positrons ([Formula: see text]) and coincidence-gamma rays (γ). The imaging system employs two planar detectors; one is a regular gamma detector which has a LYSO crystal array, and the other is a phoswich detector which has an additional BC-404 plastic scintillator for beta detection. A forward model for positrons is proposed along with a joint image reconstruction formulation to utilize the beta and coincidence-gamma measurements for estimating radioactivity distribution in plant leaves. The joint reconstruction algorithm first reconstructs beta and gamma images independently to estimate the thickness component of the beta forward model and afterward jointly estimates the radioactivity distribution in the object. We have validated the physics model and reconstruction framework through a phantom imaging study and imaging a tomato leaf that has absorbed (11)CO2. The results demonstrate that the simultaneously acquired beta and coincidence-gamma data, combined with our proposed joint reconstruction algorithm, improved the quantitative accuracy of estimating radioactivity distribution in thin objects such as leaves. We used the structural similarity (SSIM) index for comparing the leaf images from the simultaneous beta-gamma imager with the ground truth image. The jointly reconstructed images yield SSIM indices of 0

  5. Integrated multisensor perimeter detection systems

    NASA Astrophysics Data System (ADS)

    Kent, P. J.; Fretwell, P.; Barrett, D. J.; Faulkner, D. A.

    2007-10-01

    The report describes the results of a multi-year programme of research aimed at the development of an integrated multi-sensor perimeter detection system capable of being deployed at an operational site. The research was driven by end user requirements in protective security, particularly in threat detection and assessment, where effective capability was either not available or prohibitively expensive. Novel video analytics have been designed to provide robust detection of pedestrians in clutter while new radar detection and tracking algorithms provide wide area day/night surveillance. A modular integrated architecture based on commercially available components has been developed. A graphical user interface allows intuitive interaction and visualisation with the sensors. The fusion of video, radar and other sensor data provides the basis of a threat detection capability for real life conditions. The system was designed to be modular and extendable in order to accommodate future and legacy surveillance sensors. The current sensor mix includes stereoscopic video cameras, mmWave ground movement radar, CCTV and a commercially available perimeter detection cable. The paper outlines the development of the system and describes the lessons learnt after deployment in a pilot trial.

  6. Detection of DNA strand breaks in gamma-irradiated lymphocytes using surface plasmon resonance.

    PubMed

    Zhang, Xiao-hong; Lou, Zhi-chao; Wang, Ai-lian; Zhang, Hai-qian

    2013-10-01

    Surface plasmon resonance (SPR) is a sensitive, rapid, simple and low cost method for detection of biological molecules. In this study, SPR technology with alkaline phosphatase as a probe was utilized to measure DNA strand breaks induced by (60)Co gamma rays. The doses were from 0.01-10 Gy with a dose rate of 0.1 Gy/min. The results demonstrate that the SPR technology can be used to estimate strand breaks of calf thymus DNA. SPR signals of the calf thymus DNA samples increased with increasing gamma ray doses and the relationship of y = sqrt (3297x + 582.6) (r = 0.99) between the SPR signal and gamma dose was obtained. Estimation of DNA strand breaks in irradiated lymphocytes by SPR also demonstrated an increase in SPR signal with increasing dose and the exponential relationship of y = 169.43 × (1 - exp(-0.89x)) (r = 0.93) was obtained. The initial yield of the SPR signal is about 150.79 mdeg · Gy(-1) and compared to the sensitivity of 0.05 Gy achieved by the neutral single cell gel electrophoresis (SCGE), the SPR-based assay of DNA strand breaks was found to be more sensitive (0.02 Gy). We therefore propose that SPR technology with alkaline phosphatase as the probe is a sensitive, simple and quick method for detection of DNA strand breaks in gamma-irradiated lymphocytes. PMID:24010534

  7. FIGARO : detecting nuclear materials using high-energy gamma rays for oxygen.

    SciTech Connect

    Michlich, B. J.; Smith, D. L.; Massey, T. N.; Ingram, D.; Fessler, A.

    2000-10-10

    Potential diversion of nuclear materials is a major international concern. Fissile (e.g., U, Pu) and other nuclear materials (e.g., D, Be) can be detected using 6-7 MeV gamma rays produced in the {sup 19}F(p,{alpha}{gamma}){sup 16}O reaction. These gamma rays will induce neutron emission via the photoneutron and photofission processes in nuclear materials. However, they are not energetic enough to generate significant numbers of neutrons from most common benign materials, thereby reducing the false alarm rate. Neutrons are counted using an array of BF3 counters in a polyethylene moderator. Experiments have shown a strong increase in neutron count rates for depleted uranium, Be, D{sub 2}O, and {sup 6}Li, and little or no increase for other materials (e.g., H{sub 2}O, SS, Cu, Al, C, {sup 7}Li). Gamma source measurements using solid targets of CaF{sub 2} and MgF{sub 2} and a SF{sub 6} gas target show that proton accelerator of 3 MeV and 10-100 microampere average current could lead to acceptable detection sensitivity.

  8. Detection of mixed-range proton pencil beams with a prompt gamma slit camera

    NASA Astrophysics Data System (ADS)

    Priegnitz, M.; Helmbrecht, S.; Janssens, G.; Perali, I.; Smeets, J.; Vander Stappen, F.; Sterpin, E.; Fiedler, F.

    2016-01-01

    With increasing availability of proton and particle therapy centers for tumor treatment, the need for in vivo range verification methods comes more into the focus. Imaging of prompt gamma rays emitted during the treatment is one of the possibilities currently under investigation. A knife-edge shaped slit camera was recently proposed for this task and measurements proved the feasibility of range deviation detection in homogeneous and inhomogeneous targets. In the present paper, we concentrate on laterally inhomogeneous materials, which lead to range mixing situations when crossed by one pencil beam: different sections of the beam have different ranges. We chose exemplative cases from clinical irradiation and assembled idealized tissue equivalent targets. One-dimensional emission profiles were obtained by measuring the prompt gamma emission with the slit camera. It could be shown that the resulting range deviations can be detected by evaluation of the measured data with a previously developed range deviation detection algorithm. The retrieved value, however, strongly depends on the target composition, and is not necessarily in direct relation to the ranges of both parts of the beam. By combining the range deviation detection with an analysis of the slope of the distal edge of the measured prompt gamma profile, the origin of the detected range deviation, i.e. the mixed range of the beam, is also identified. It could be demonstrated that range mixed prompt gamma profiles exhibit less steep distal slopes than profiles from beams traversing laterally homogeneous material. For future application of the slit camera to patient irradiation with double scattered proton beams, situations similar to the range mixing cases are present and results could possibly apply.

  9. Integrated Operation of the GАММА-400 Gamma-Ray Telescope Scintillation Detector Systems

    NASA Astrophysics Data System (ADS)

    Runtso, Mikhail

    In this paper the question of integrated operation of scintillation detector systems AC (anticoincidence system) and SDC (scintillation detector system of calorimeter) in the GАММА-400 gamma-ray telescope is discussed. The main problem is the presence of so-called «backsplash current» (BSC) of particles from massive telescope calorimeter when detecting of very high-energy gamma-rays is provided. BSC is a low energy particle flux, moving up from the calorimeter and producing triggering of the AC detector, imitating detection of a charged particle. It is offered to record all events accompanied by BSC that should not result in to overload of the gamma-ray telescope in frequency of triggering. As an indicator to the number of BSC particles in the AC detector we offer the value of energy release in the C3 scintillation detector placing between two parts of the calorimeter (KK1 and KK2). Using mathematical simulation, the threshold on energy release in the C3 detector equal to 280 GeV was determined, at which the losses of gamma-quanta number in events with BSC do not exceed 10%. When detecting protons there are also events with BSC, which will be accompanied by exceeding of the indicated threshold of energy release in the С3 detector for proton energies above 30 GeV. However, counting rate for such protons will not exceed 200 Hz, that is reasonable for the GAMMA-400 data acquisition system.

  10. High voltage stability performance of a gamma ray detection device

    SciTech Connect

    Abdullah, Nor Arymaswati; Lombigit, Lojius; Rahman, Nur Aira Abd

    2014-02-12

    An industrial grade digital radiation survey meter device is currently being developed at Malaysian Nuclear Agency. This device used a cylindrical type Geiger Mueller (GM) which acts as a detector. GM detector operates at relatively high direct current voltages depend on the type of GM tube. This thin/thick walled cylindrical type of GM tube operates at 450-650 volts range. Proper value and stability performance of high voltage are important parameters to ensure that this device give a reliable radiation dose measurement. This paper will present an assessment of the stability and performance of the high voltage supply for radiation detector. The assessment is performed using System Identification tools box in MATLAB and mathematical statistics.

  11. A performance study of an electron-tracking Compton camera with a compact system for environmental gamma-ray observation

    NASA Astrophysics Data System (ADS)

    Mizumoto, T.; Tomono, D.; Takada, A.; Tanimori, T.; Komura, S.; Kubo, H.; Matsuoka, Y.; Mizumura, Y.; Nakamura, K.; Nakamura, S.; Oda, M.; Parker, J. D.; Sawano, T.; Bando, N.; Nabetani, A.

    2015-06-01

    An electron-tracking Compton camera (ETCC) is a detector that can determine the arrival direction and energy of incident sub-MeV/MeV gamma-ray events on an event-by-event basis. It is a hybrid detector consisting of a gaseous time projection chamber (TPC), that is the Compton-scattering target and the tracker of recoil electrons, and a position-sensitive scintillation camera that absorbs of the scattered gamma rays, to measure gamma rays in the environment from contaminated soil. To measure of environmental gamma rays from soil contaminated with radioactive cesium (Cs), we developed a portable battery-powered ETCC system with a compact readout circuit and data-acquisition system for the SMILE-II experiment [1,2]. We checked the gamma-ray imaging ability and ETCC performance in the laboratory by using several gamma-ray point sources. The performance test indicates that the field of view (FoV) of the detector is about 1 sr and that the detection efficiency and angular resolution for 662 keV gamma rays from the center of the FoV is (9.31 ± 0.95) × 10-5 and 5.9° ± 0.6°, respectively. Furthermore, the ETCC can detect 0.15 μSv/h from a 137Cs gamma-ray source with a significance of 5σ in 13 min in the laboratory. In this paper, we report the specifications of the ETCC and the results of the performance tests. Furthermore, we discuss its potential use for environmental gamma-ray measurements.

  12. Low gamma counting for measuring NORM/TENORM with a radon reducing system

    NASA Astrophysics Data System (ADS)

    Paschoa, Anselmo S.

    2001-06-01

    A detection system for counting low levels of gamma radiation was built by upgrading an existing rectangular chamber made of 18 metric tonne of steel fabricated before World War II. The internal walls, the ceiling, and the floor of the chamber are covered with copper sheets. The new detection system consists of a stainless steel hollow cylinder with variable circular apertures in the cylindrical wall and in the base, to allow introduction of a NaI (Tl) crystal, or alternatively, a HPGe detector in its interior. This counting system is mounted inside the larger chamber, which in turn is located in a subsurface air-conditioned room. The access to the subsurface room is made from a larger entrance room through a tunnel plus a glass anteroom to decrease the air-exchange rate. Both sample and detector are housed inside the stainless steel cylinder. This cylinder is filled with hyper pure nitrogen gas, before counting a sample, to prevent radon coming into contact with the detector surface. As a consequence, the contribution of the 214Bi photopeaks to the background gamma spectra is minimized. The reduction of the gamma radiation background near the detector facilitates measurement of naturally occurring radioactive materials (NORM), and/or technologically enhanced NORM (TENORM), which are usually at concentration levels only slightly higher than those typically found in the natural radioactive background.

  13. AGILE detection of enhanced gamma-ray emission from the Crab Nebula region

    NASA Astrophysics Data System (ADS)

    Tavani, M.; Striani, E.; Bulgarelli, A.; Gianotti, F.; Trifoglio, M.; Pittori, C.; Verrecchia, F.; Argan, A.; Trois, A.; de Paris, G.; Vittorini, V.; D'Ammando, F.; Sabatini, S.; Piano, G.; Costa, E.; Donnarumma, I.; Feroci, M.; Pacciani, L.; Del Monte, E.; Lazzarotto, F.; Soffitta, P.; Evangelista, Y.; Lapshov, I.; Chen, A.; Giuliani, A.; Marisaldi, M.; Di Cocco, G.; Labanti, C.; Fuschino, F.; Galli, M.; Caraveo, P.; Mereghetti, S.; Perotti, F.; Pucella, G.; Rapisarda, M.; Vercellone, S.; Pellizzoni, A.; Pilia, M.; Barbiellini, G.; Longo, F.; Picozza, P.; Morselli, A.; Prest, M.; Lipari, P.; Zanello, D.; Cattaneo, P. W.; Rappoldi, A.; Giommi, P.; Santolamazza, P.; Lucarelli, F.; Colafrancesco, S.; Salotti, L.

    2010-09-01

    AGILE is detecting an increased gamma-ray flux from a source positionally consistent with the Crab Nebula. Integrating during the period 2010-09-19 00:10 UT to 2010-09-21 00:10 UT the AGILE-GRID detected enhanced gamma-ray emission above 100 MeV from a source at Galactic coordinates (l,b) = (184.6, -6.0) +/- 0.4 (stat.) +/- 0.1 (syst.) deg, and flux F > 500 e-8 ph/cm2/sec above 100 MeV, corresponding to an excess with significance above 4.4 sigma with respect to the average flux from the Crab nebula (F = (220 +/- 15)e-8 ph/cm^2/sec, Pittori et al., 2009, A&A, 506, 1563).

  14. Stand-alone and Network Capable Pocket Radiation Detection System

    SciTech Connect

    R. Aryaeinejad

    2009-03-01

    A multi-functional and networked pocket radiation detection system has been developed at the Idaho National Laboratory (INL) capable of detecting and storing gamma ray and neutron data. The device can be used as a stand-alone device or in conjunction with an array to cover a small or large area. The device has programmable alarm trigger levels that can be modified for specific applications. The data is stored with a date/time stamp and can be transferred and viewed on a PDA via direct connection or, in networked configuration, wireless connection to a remote central facility upon request. Data functional/bench tests have been completed successfully and the device was demonstrated to detect radiation from a 55.6 uCi Cf-252 source at 5 meters and from 1.4 mCi Cf-252 source at 10 meters which exceeds both ANSI and IAEA standards for pocket radiation detection. In terms of sensitivity, this detection system detects neutron and gamma-ray fields down to 10 micro rem/hr levels and therefore can find the location of the radioactive source quickly. The detection system is small enough to be put in a pocket or clipped to a belt.

  15. Hearing aid malfunction detection system

    NASA Technical Reports Server (NTRS)

    Kessinger, R. L. (Inventor)

    1977-01-01

    A malfunction detection system for detecting malfunctions in electrical signal processing circuits is disclosed. Malfunctions of a hearing aid in the form of frequency distortion and/or inadequate amplification by the hearing aid amplifier, as well as weakening of the hearing aid power supply are detectable. A test signal is generated and a timed switching circuit periodically applies the test signal to the input of the hearing aid amplifier in place of the input signal from the microphone. The resulting amplifier output is compared with the input test signal used as a reference signal. The hearing aid battery voltage is also periodically compared to a reference voltage. Deviations from the references beyond preset limits cause a warning system to operate.

  16. Systematic Assessment of Neutron and Gamma Backgrounds Relevant to Operational Modeling and Detection Technology Implementation

    SciTech Connect

    Archer, Daniel E.; Hornback, Donald Eric; Johnson, Jeffrey O.; Nicholson, Andrew D.; Patton, Bruce W.; Peplow, Douglas E.; Miller, Thomas Martin; Ayaz-Maierhafer, Birsen

    2015-01-01

    This report summarizes the findings of a two year effort to systematically assess neutron and gamma backgrounds relevant to operational modeling and detection technology implementation. The first year effort focused on reviewing the origins of background sources and their impact on measured rates in operational scenarios of interest. The second year has focused on the assessment of detector and algorithm performance as they pertain to operational requirements against the various background sources and background levels.

  17. A novel detector assembly for detecting thermal neutrons, fast neutrons and gamma rays

    NASA Astrophysics Data System (ADS)

    Cester, D.; Lunardon, M.; Moretto, S.; Nebbia, G.; Pino, F.; Sajo-Bohus, L.; Stevanato, L.; Bonesso, I.; Turato, F.

    2016-09-01

    A new composite detector has been developed by combining two different commercial scintillators. The device has the capability to detect gamma rays as well as thermal and fast neutrons; the signal discrimination between the three types is performed on-line by means of waveform digitizers and PSD algorithms. This work describes the assembled detector and its discrimination performance to be employed in the applied field.

  18. AGILE detection of enhanced gamma-ray emission from the FSRQ 4C +01.02

    NASA Astrophysics Data System (ADS)

    Verrecchia, F.; Lucarelli, F.; Pittori, C.; Bulgarelli, A.; Tavani, M.; Fioretti, V.; Zoli, A.; Piano, G.; Striani, E.; Vercellone, S.; Donnarumma, I.; Cardillo, M.; Gianotti, F.; Trifoglio, M.; Giuliani, A.; Mereghetti, S.; Caraveo, P.; Perotti, F.; Chen, A.; Argan, A.; Costa, E.; Del Monte, E.; Evangelista, Y.; Feroci, M.; Lazzarotto, F.; Lapshov, I.; Pacciani, L.; Soffitta, P.; Sabatini, S.; Vittorini, V.; Pucella, G.; Rapisarda, M.; Di Cocco, G.; Fuschino, F.; Galli, M.; Labanti, C.; Marisaldi, M.; Pellizzoni, A.; Pilia, M.; Trois, A.; Barbiellini, G.; Vallazza, E.; Longo, F.; Morselli, A.; Picozza, P.; Prest, M.; Lipari, P.; Zanello, D.; Cattaneo, P. W.; Rappoldi, A.; Colafrancesco, S.; Parmiggiani, N.; Ferrari, A.; Antonelli, A.; Giommi, P.; Salotti, L.; Valentini, G.; D'Amico, F.

    2016-07-01

    AGILE is detecting increased gamma-ray emission above 100 MeV from a position consistent with the flat spectrum radio quasar 4C +01.02 (also known as 5BZQ J0108+0135, PKS 0106+01 and 3FGL J0108.7+0134), recently reported in flaring activity also by Fermi/LAT during the week Jun 6-12 (http://fermisky.blogspot.it).

  19. High-efficiency scintillation detector for combined detection of thermal and fast neutrons and gamma radiation

    DOEpatents

    Chiles, M.M.; Mihalczo, J.T.; Blakeman, E.D.

    1987-02-27

    A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation event count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

  20. Semi autonomous mine detection system

    SciTech Connect

    Douglas Few; Roelof Versteeg; Herman Herman

    2010-04-01

    CMMAD is a risk reduction effort for the AMDS program. As part of CMMAD, multiple instances of semi autonomous robotic mine detection systems were created. Each instance consists of a robotic vehicle equipped with sensors required for navigation and marking, a countermine sensors and a number of integrated software packages which provide for real time processing of the countermine sensor data as well as integrated control of the robotic vehicle, the sensor actuator and the sensor. These systems were used to investigate critical interest functions (CIF) related to countermine robotic systems. To address the autonomy CIF, the INL developed RIK was extended to allow for interaction with a mine sensor processing code (MSPC). In limited field testing this system performed well in detecting, marking and avoiding both AT and AP mines. Based on the results of the CMMAD investigation we conclude that autonomous robotic mine detection is feasible. In addition, CMMAD contributed critical technical advances with regard to sensing, data processing and sensor manipulation, which will advance the performance of future fieldable systems. As a result, no substantial technical barriers exist which preclude – from an autonomous robotic perspective – the rapid development and deployment of fieldable systems.

  1. Portable Microleak-Detection System

    NASA Technical Reports Server (NTRS)

    Rivers, H. Kevin; Sikora, Joseph G.; Sankaran, Sankara N.

    2007-01-01

    The figure schematically depicts a portable microleak-detection system that has been built especially for use in testing hydrogen tanks made of polymer-matrix composite materials. (As used here, microleak signifies a leak that is too small to be detectable by the simple soap-bubble technique.) The system can also be used to test for microleaks in tanks that are made of other materials and that contain gases other than hydrogen. Results of calibration tests have shown that measurement errors are less than 10 percent for leak rates ranging from 0.3 to 200 cm3/min. Like some other microleak-detection systems, this system includes a vacuum pump and associated plumbing for sampling the leaking gas, and a mass spectrometer for analyzing the molecular constituents of the gas. The system includes a flexible vacuum chamber that can be attached to the outer surface of a tank or other object of interest that is to be tested for leakage (hereafter denoted, simply, the test object). The gas used in a test can be the gas or vapor (e.g., hydrogen in the original application) to be contained by the test object. Alternatively, following common practice in leak testing, helium can be used as a test gas. In either case, the mass spectrometer can be used to verify that the gas measured by the system is the test gas rather than a different gas and, hence, that the leak is indeed from the test object.

  2. AGILE detection of intense gamma-ray emission from the blazar PKS 1510-089

    NASA Astrophysics Data System (ADS)

    Pucella, G.; Vittorini, V.; D'Ammando, F.; Tavani, M.; Raiteri, C. M.; Villata, M.; Argan, A.; Barbiellini, G.; Boffelli, F.; Bulgarelli, A.; Caraveo, P.; Cattaneo, P. W.; Chen, A. W.; Cocco, V.; Costa, E.; Del Monte, E.; de Paris, G.; Di Cocco, G.; Donnarumma, I.; Evangelista, Y.; Feroci, M.; Fiorini, M.; Froysland, T.; Fuschino, F.; Galli, M.; Gianotti, F.; Giuliani, A.; Labanti, C.; Lapshov, I.; Lazzarotto, F.; Lipari, P.; Longo, F.; Marisaldi, M.; Mereghetti, S.; Morselli, A.; Pacciani, L.; Pellizzoni, A.; Perotti, F.; Picozza, P.; Prest, M.; Rapisarda, M.; Rappoldi, A.; Soffitta, P.; Trifoglio, M.; Trois, A.; Vallazza, E.; Vercellone, S.; Zambra, A.; Zanello, D.; Antonelli, L. A.; Colafrancesco, S.; Cutini, S.; Gasparrini, D.; Giommi, P.; Pittori, C.; Verrecchia, F.; Salotti, L.; Aller, M. F.; Aller, H. D.; Carosati, D.; Larionov, V. M.; Ligustri, R.

    2008-11-01

    Context: We report the detection by the AGILE (Astro-rivelatore Gamma a Immagini LEggero) satellite of an intense gamma-ray flare from the source AGL J1511-0909, associated with the powerful quasar PKS 1510-089, during ten days of observations from 23 August to 1 September 2007. Aims: During the observation period, the source was in optical decrease following a flaring event monitored by the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT). The simultaneous gamma-ray, optical, and radio coverage allows us to study the spectral energy distribution and the theoretical models based on the synchrotron and inverse Compton (IC) emission mechanisms. Methods: AGILE observed the source with its two co-aligned imagers, the Gamma-Ray Imaging Detector and the hard X-ray imager Super-AGILE sensitive in the 30 MeV div 50 GeV and 18 div 60 keV bands, respectively. Results: Between 23 and 27 August 2007, AGILE detected gamma-ray emission from PKS 1510-089 when this source was located 50° off-axis, with an average flux of (270 ± 65) × 10-8 photons cm-2 s-1 for photon energy above 100 MeV. In the following period, 28 August-1 September, after a satellite re-pointing, AGILE detected the source at 35° off-axis, with an average flux (E > 100 MeV) of (195 ± 30) × 10-8 photons cm-2 s-1. No emission was detected by Super-AGILE, with a 3-σ upper limit of 45 mCrab in 200 ks. Conclusions: The spectral energy distribution is modelled with a homogeneous one-zone synchrotron self Compton (SSC) emission plus contributions by external photons: the SSC emission contributes primarily to the X-ray band, whereas the contribution of the IC from the external disc and the broad line region match the hard gamma-ray spectrum observed.

  3. Evaluation of gamma interferon (IFN-gamma)-induced protein 10 (IP-10) responses for detection of cattle infected with Mycobacterium bovis: comparisons to IFN-gamma responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gamma interferon (IFN-gamma)-induced protein 10 (IP-10) has recently shown promise as a diagnostic biomarker of Mycobacterium tuberculosis infection of humans. The aim of the current study was to compare IP-10 and IFN-gamma responses upon Mycobacterium bovis infection in cattle using archived sample...

  4. X-RED: a satellite mission concept to detect early universe gamma ray bursts

    NASA Astrophysics Data System (ADS)

    Krumpe, Mirko; Coffey, Deirdre; Egger, Georg; Vilardell, Francesc; Lefever, Karolien; Liermann, Adriane; Hoffmann, Agnes I.; Steiper, Joerg; Cherix, Marc; Albrecht, Simon; Russo, Pedro; Strodl, Thomas; Wahlin, Rurik; Deroo, Pieter; Parmar, Arvind; Lund, Niels; Hasinger, Gunther

    2005-01-01

    Gamma ray bursts (GRBs) are the most energetic eruptions known in the Universe. Instruments such as Compton-GRO/BATSE and the GRB monitor on BeppoSAX have detected more than 2700 GRBs and, although observational confirmation is still required, it is now generally accepted that many of these bursts are associated with the collapse of rapidly spinning massive stars to form black holes. Consequently, since first generation stars are expected to be very massive, GRBs are likely to have occurred in significant numbers at early epochs. X-red is a space mission concept designed to detect these extremely high redshifted GRBs, in order to probe the nature of the first generation of stars and hence the time of reionisation of the early Universe. We demonstrate that the gamma and x-ray luminosities of typical GRBs render them detectable up to extremely high redshifts (z ~ 10to30), but that current missions such as HETES and SWIFT operate outside the observational range for detection of high redshift GRB afterglows. Therefore, to redress this, we present a complete mission design from teh science case to the mission architecture and payload, the latter comprising three instruments, namely wide field x-ray cameras to detect high redshift gamma-rays, an x-ray focussing telescope to determine accurate coordinates and extract spectra, and an infrared spectrograph to observe the high redshift optical afterglow. The mission is expected to detect and identify for the first time GRBs with z > 10, thereby providing constraints on properties of the first generation of stars and the history of the early Universe.

  5. X-RED: a satellite mission concept to detect early universe gamma ray bursts

    NASA Astrophysics Data System (ADS)

    Krumpe, Mirko; Coffey, Deirdre; Egger, Georg; Vilardell, Francesc; Lefever, Karolien; Liermann, Adriane; Hoffmann, Agnes I.; Steiper, Joerg; Cherix, Marc; Albrecht, Simon; Russo, Pedro; Strodl, Thomas; Wahlin, Rurik; Deroo, Pieter; Parmar, Arvind; Lund, Niels; Hasinger, Gunther

    2005-08-01

    Gamma ray bursts (GRBs) are the most energetic eruptions known in the Universe. Instruments such as Compton-GRO/BATSE and the GRB monitor on BeppoSAX have detected more than 2700 GRBs and, although observational confirmation is still required, it is now generally accepted that many of these bursts are associated with the collapse of rapidly spinning massive stars to form black holes. Consequently, since first generation stars are expected to be very massive, GRBs are likely to have occurred in significant numbers at early epochs. X-red is a space mission concept designed to detect these extremely high redshifted GRBs, in order to probe the nature of the first generation of stars and hence the time of reionisation of the early Universe. We demonstrate that the gamma and x-ray luminosities of typical GRBs render them detectable up to extremely high redshifts (z ~ 10to30), but that current missions such as HETES and SWIFT operate outside the observational range for detection of high redshift GRB afterglows. Therefore, to redress this, we present a complete mission design from teh science case to the mission architecture and payload, the latter comprising three instruments, namely wide field x-ray cameras to detect high redshift gamma-rays, an x-ray focussing telescope to determine accurate coordinates and extract spectra, and an infrared spectrograph to observe the high redshift optical afterglow. The mission is expected to detect and identify for the first time GRBs with z > 10, thereby providing constraints on properties of the first generation of stars and the history of the early Universe.

  6. Foundations for Improvements to Passive Detection Systems - Final Report

    SciTech Connect

    Labov, S E; Pleasance, L; Sokkappa, P; Craig, W; Chapline, G; Frank, M; Gronberg, J; Jernigan, J G; Johnson, S; Kammeraad, J; Lange, D; Meyer, A; Nelson, K; Pohl, B; Wright, D; Wurtz, R

    2004-10-07

    This project explores the scientific foundation and approach for improving passive detection systems for plutonium and highly enriched uranium in real applications. Sources of gamma-ray radiation of interest were chosen to represent a range of national security threats, naturally occurring radioactive materials, industrial and medical radiation sources, and natural background radiation. The gamma-ray flux emerging from these sources, which include unclassified criticality experiment configurations as surrogates for nuclear weapons, were modeled in detail. The performance of several types of gamma-ray imaging systems using Compton scattering were modeled and compared. A mechanism was created to model the combine sources and background emissions and have the simulated radiation ''scene'' impinge on a model of a detector. These modeling tools are now being used in various projects to optimize detector performance and model detector sensitivity in complex measuring environments. This study also developed several automated algorithms for isotope identification from gamma-ray spectra and compared these to each other and to algorithms already in use. Verification testing indicates that these alternative isotope identification algorithms produced less false positive and false negative results than the ''GADRAS'' algorithms currently in use. In addition to these algorithms that used binned spectra, a new approach to isotope identification using ''event mode'' analysis was developed. Finally, a technique using muons to detect nuclear material was explored.

  7. Neutron monitoring systems including gamma thermometers and methods of calibrating nuclear instruments using gamma thermometers

    SciTech Connect

    Moen, Stephan Craig; Meyers, Craig Glenn; Petzen, John Alexander; Foard, Adam Muhling

    2012-08-07

    A method of calibrating a nuclear instrument using a gamma thermometer may include: measuring, in the instrument, local neutron flux; generating, from the instrument, a first signal proportional to the neutron flux; measuring, in the gamma thermometer, local gamma flux; generating, from the gamma thermometer, a second signal proportional to the gamma flux; compensating the second signal; and calibrating a gain of the instrument based on the compensated second signal. Compensating the second signal may include: calculating selected yield fractions for specific groups of delayed gamma sources; calculating time constants for the specific groups; calculating a third signal that corresponds to delayed local gamma flux based on the selected yield fractions and time constants; and calculating the compensated second signal by subtracting the third signal from the second signal. The specific groups may have decay time constants greater than 5.times.10.sup.-1 seconds and less than 5.times.10.sup.5 seconds.

  8. Tape Cassette Bacteria Detection System

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The design, fabrication, and testing of an automatic bacteria detection system with a zero-g capability and based on the filter-capsule approach is described. This system is intended for monitoring the sterility of regenerated water in a spacecraft. The principle of detection is based on measuring the increase in chemiluminescence produced by the action of bacterial porphyrins (i.e., catalase, cytochromes, etc.) on a luminol-hydrogen peroxide mixture. Since viable as well as nonviable organisms initiate this luminescence, viable organisms are detected by comparing the signal of an incubated water sample with an unincubated control. Higher signals for the former indicate the presence of viable organisms. System features include disposable sealed sterile capsules, each containing a filter membrane, for processing discrete water samples and a tape transport for moving these capsules through a processing sequence which involves sample concentration, nutrient addition, incubation, a 4 Molar Urea wash and reaction with luminol-hydrogen peroxide in front of a photomultiplier tube. Liquids are introduced by means of a syringe needle which pierces a rubber septum contained in the wall of the capsule. Detection thresholds obtained with this unit towards E. coli and S. marcescens assuming a 400 ml water sample are indicated.

  9. AGILE detection of increased gamma-ray emission from the FSRQ PKS 1313-333

    NASA Astrophysics Data System (ADS)

    Lucarelli, F.; Verrecchia, F.; Bulgarelli, A.; Pittori, C.; Tavani, M.; Fioretti, V.; Zoli, A.; Vercellone, S.; Donnarumma, I.; Piano, G.; Striani, E.; Cardillo, M.; Gianotti, F.; Trifoglio, M.; Giuliani, A.; Mereghetti, S.; Caraveo, P.; Perotti, F.; Chen, A.; Argan, A.; Costa, E.; Del Monte, E.; Evangelista, Y.; Feroci, M.; Lazzarotto, F.; Lapshov, I.; Pacciani, L.; Soffitta, P.; Sabatini, S.; Vittorini, V.; Pucella, G.; Rapisarda, M.; Di Cocco, G.; Fuschino, F.; Galli, M.; Labanti, C.; Marisaldi, M.; Pellizzoni, A.; Pilia, M.; Trois, A.; Barbiellini, G.; Vallazza, E.; Longo, F.; Morselli, A.; Picozza, P.; Prest, M.; Lipari, P.; Zanello, D.; Cattaneo, P. W.; Rappoldi, A.; Colafrancesco, S.; Parmiggiani, N.; Ferrari, A.; Antonelli, A.; Giommi, P.; Salotti, L.; Valentini, G.; D'Amico, F.

    AGILE confirms the detection of enhanced gamma-ray activity from the FSRQ PKS 1313-333 (redshift z=1.210), as reported by the Fermi-LAT in ATel #8533. Integrating from 2016-01-10 02:00 UT to 2016-01-12 02:00 UT, a maximum likelihood analysis of AGILE data yields the detection of the source at a significance level of about 5 sigma with a flux of (1.6 +/- 0.6) x 10^-6 ph/cm2/s (E > 100 MeV), in agreement with the Fermi-LAT measurement.

  10. AGILE detection of increasing gamma-ray activity from the Blazar 3C 454.3

    NASA Astrophysics Data System (ADS)

    Lucarelli, F.; Pittori, C.; Verrecchia, F.; Bulgarelli, A.; Fioretti, V.; Zoli, A.; Piano, G.; Munar-Adrover, P.; Tavani, M.; Donnarumma, I.; Vercellone, S.; Striani, E.; Cardillo, M.; Gianotti, F.; Trifoglio, M.; Giuliani, A.; Mereghetti, S.; Caraveo, P.; Perotti, F.; Chen, A.; Argan, A.; Costa, E.; Del Monte, E.; Evangelista, Y.; Feroci, M.; Lazzarotto, F.; Lapshov, I.; Pacciani, L.; Soffitta, P.; Sabatini, S.; Vittorini, V.; Pucella, G.; Rapisarda, M.; Di Cocco, G.; Fuschino, F.; Galli, M.; Labanti, C.; Marisaldi, M.; Pellizzoni, A.; Pilia, M.; Trois, A.; Barbiellini, G.; Vallazza, E.; Longo, F.; Morselli, A.; Picozza, P.; Prest, M.; Lipari, P.; Zanello, D.; Cattaneo, P. W.; Rappoldi, A.; Colafrancesco, S.; Parmiggiani, N.; Ferrari, A.; Antonelli, A.; Giommi, P.; Salotti, L.; Valentini, G.; D'Amico, F.

    2016-06-01

    The AGILE satellite is detecting an enhancement of gamma-ray emission above 100 MeV from the FSRQ 3C 454.3. Integrating from 2016-06-11 01:00 UT to 2016-06-15 01:00 UT, a maximum likelihood analysis yields the detection of the source with a flux of (2.7 +/- 0.7) x 10^-6 ph/cm2/s (E > 100 MeV), at a significance level above 5 sigma.

  11. Cosmic gamma-ray burst detected with an instrument on board the OGO-5 satellite

    NASA Technical Reports Server (NTRS)

    Lheureux, J.

    1974-01-01

    Gamma-ray bursts of cosmic origin have recently been detected by instruments on the Vela satellites. We now confirm the detection of the June 30, 1971 event with an instrument on board the OGO-5 satellite. The intensity of this burst is calculated to be approximately 100-200 photons per sq cm/sec for photons of energy greater than 150 keV with an upper limit of 50 photons per sq cm/sec for the intensity above 5 MeV. An upper limit of one-third of the intensity of the June 30, 1971 event is set for 10 other events studied.

  12. Neutron-based land mine detection system development

    SciTech Connect

    Davis, H.A.; McDonald, T.E. Jr.; Nebel, R.A.; Pickrell, M.M.

    1997-10-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project was to examine the feasibility of developing a land mine detection system that can detect nonmetallic (plastic) mines using the detection and analysis of prompt gamma neutron activation analysis (PGNAA). The authors approached this study by first carrying out a review of other nonmetallic land mine detection methods for comparison with the PGNAA concept. They reviewed issues associated with detecting and recording the return gamma signal resulting from neutrons interacting with high explosive in mines and they examined two neutron source technologies that have been under development at Los Alamos for the past several years for possible application to a PGNAA system. A major advantage of the PGNAA approach is it`s ability to discriminate detection speed and need for close proximity. The authors identified approaches to solving these problems through development of improved neutron sources and detection sensors.

  13. Gamma ray transients

    NASA Technical Reports Server (NTRS)

    Cline, Thomas L.

    1987-01-01

    The discovery of cosmic gamma ray bursts was made with systems designed at Los Alamos Laboratory for the detection of nuclear explosions beyond the atmosphere. HELIOS-2 was the first gamma ray burst instrument launched; its initial results in 1976, seemed to deepen the mystery around gamma ray transients. Interplanetary spacecraft data were reviewed in terms of explaining the behavior and source of the transients.

  14. 21 CFR 862.1360 - Gamma-glutamyl transpeptidase and isoenzymes test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1360 Gamma-glutamyl transpeptidase and isoenzymes test system....

  15. 21 CFR 862.1360 - Gamma-glutamyl transpeptidase and isoenzymes test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1360 Gamma-glutamyl transpeptidase and isoenzymes test system....

  16. Laser System for Livermore's Mono Energetic Gamma-Ray Source

    SciTech Connect

    Gibson, D; Albert, F; Bayramian, A; Marsh, R; Messerly, M; Ebbers, C; Hartemann, F

    2011-03-14

    A Mono-energetic Gamma-ray (MEGa-ray) source, based on Compton scattering of a high-intensity laser beam off a highly relativistic electron beam, requires highly specialized laser systems. To minimize the bandwidth of the {gamma}-ray beam, the scattering laser must have minimal bandwidth, but also match the electron beam depth of focus in length. This requires a {approx}1 J, 10 ps, fourier-transform-limited laser system. Also required is a high-brightness electron beam, best provided by a photoinjector. This electron source requires a second laser system with stringent requirements on the beam including flat transverse and longitudinal profiles and fast rise times. Furthermore, these systems must be synchronized to each other with ps-scale accuracy. Using a novel hyper-dispersion compressor configuration and advanced fiber amplifiers and diode-pumped Nd:YAG amplifiers, we have designed laser systems that meet these challenges for the X-band photoinjector and Compton-scattering source being built at Lawrence Livermore National Laboratory.

  17. Fiber optic hydrogen detection system

    NASA Astrophysics Data System (ADS)

    Kazemi, Alex A.; Larson, David B.; Wuestling, Mark D.

    1999-12-01

    Commercial and military launch vehicles are designed to use hydrogen as the main propellant, which is very volatile, extremely flammable, and highly explosive. Current detection systems uses Teflon transfer tubes at a large number of vehicle locations through which gas samples are drawn and the stream analyzed by a mass spectrometer. A concern with this approach is the high cost of the system. Also, the current system does not provide leak location and is not in real-time. This system is very complex and cumbersome for production and ground support measurement personnel. The fiber optic micromirror sensor under development for cryogenic environment relies on a reversible chemical interaction causing a change in reflectivity of a thin film of coated Palladium. The magnitude of the reflectivity change is correlated to hydrogen concentration. The sensor uses only a tiny light beam, with no electricity whatsoever at the sensor, leading to devices that is intrinsically safe from explosive ignition. The sensor, extremely small in size and weight detects, hydrogen concentration using a passive element consisting of chemically reactive microcoatings deposited on the surface of a glass microlens, which is then bonded to an optical fiber. The system uses a multiplexing technique with a fiber optic driver-receiver consisting of a modulated LED source that is launched into the sensor, and a photodiode detector that synchronously measures the reflected signal. The system incorporates a microprocessor (or PC) to perform the data analysis and storage, as well as trending and set alarm function. As it is a low cost system with a fast response, many more detection sensors can be used that will be extremely helpful in determining leak location for safety of crew and vehicles during launch operations.

  18. Detection of Defects in Acrylic and Steel Inclusions in Gypsum Using Compton Backscattered Gamma Rays

    NASA Astrophysics Data System (ADS)

    Boldo, Emerson M.; Appoloni, Carlos R.

    2011-08-01

    Compton scattering of gamma radiation is a nondestructive technique used for the detection of defects and inclusions in materials. The methodology allows one-side inspection of large structures, is relatively inexpensive and can be portable. The number of photons inelastically scattered within a well-defined volume element is linearly proportional to the electron density of the material. Targeting a sample with a collimated beam of gamma rays, the energy spectrum of backscattered photons can be used to determine local density perturbations. In this work we used the Compton backscattering technique to detection of small collinear defects in acrylic blocks and steel rods inclusions in gypsum blocks samples. The samples were irradiated with gamma rays from a O/2 mm collimated 241Am (100 mCi) source and the inelastically scattered photons were collected at an angle of 135° by a CdTe detector with a O/7 mm×30 mm collimation. Scanning was achieved by lateral movement of the sample blocks across the source and detector field of view in steps of 1 mm. The results showed that defects in the acrylic samples as small as 3 mm in size were visible in the intensity versus energy spectrum. The tests on gypsum blocks with steel rods inclusions suggest that, for a low energy and activity source, the effects of beam attenuation are more decisive to the scattered intensity than increasing of material density. An analysis of the density contrast is also presented.

  19. The Autonomous Pathogen Detection System

    SciTech Connect

    Dzenitis, J M; Makarewicz, A J

    2009-01-13

    We developed, tested, and now operate a civilian biological defense capability that continuously monitors the air for biological threat agents. The Autonomous Pathogen Detection System (APDS) collects, prepares, reads, analyzes, and reports results of multiplexed immunoassays and multiplexed PCR assays using Luminex{copyright} xMAP technology and flow cytometer. The mission we conduct is particularly demanding: continuous monitoring, multiple threat agents, high sensitivity, challenging environments, and ultimately extremely low false positive rates. Here, we introduce the mission requirements and metrics, show the system engineering and analysis framework, and describe the progress to date including early development and current status.

  20. Detecting transition in agricultural systems

    NASA Technical Reports Server (NTRS)

    Neary, P. J.; Coiner, J. C.

    1979-01-01

    Remote sensing of agricultural phenomena has been largely concentrated on analysis of agriculture at the field level. Concern has been to identify crop status, crop condition, and crop distribution, all of which are spatially analyzed on a field-by-field basis. A more general level of abstraction is the agricultural system, or the complex of crops and other land cover that differentiate various agricultural economies. The paper reports on a methodology to assist in the analysis of the landscape elements of agricultural systems with Landsat digital data. The methodology involves tracing periods of photosynthetic activity for a fixed area. Change from one agricultural system to another is detected through shifts in the intensity and periodicity of photosynthetic activity as recorded in the radiometric return to Landsat. The Landsat-derived radiometric indicator of photosynthetic activity appears to provide the ability to differentiate agricultural systems from each other as well as from conterminous natural vegetation.

  1. Nucleic acid detection system and method for detecting influenza

    SciTech Connect

    Cai, Hong; Song, Jian

    2015-03-17

    The invention provides a rapid, sensitive and specific nucleic acid detection system which utilizes isothermal nucleic acid amplification in combination with a lateral flow chromatographic device, or DNA dipstick, for DNA-hybridization detection. The system of the invention requires no complex instrumentation or electronic hardware, and provides a low cost nucleic acid detection system suitable for highly sensitive pathogen detection. Hybridization to single-stranded DNA amplification products using the system of the invention provides a sensitive and specific means by which assays can be multiplexed for the detection of multiple target sequences.

  2. Compensated intruder-detection systems

    DOEpatents

    McNeilly, David R.; Miller, William R.

    1984-01-01

    Intruder-detection systems in which intruder-induced signals are transmitted through a medium also receive spurious signals induced by changes in a climatic condition affecting the medium. To combat this, signals received from the detection medium are converted to a first signal. The system also provides a reference signal proportional to climate-induced changes in the medium. The first signal and the reference signal are combined for generating therefrom an output signal which is insensitive to the climatic changes in the medium. An alarm is energized if the output signal exceeds a preselected value. In one embodiment, an acoustic cable is coupled to a fence to generate a first electrical signal proportional to movements thereof. False alarms resulting from wind-induced movements of the fence (detection medium) are eliminated by providing an anemometer-driven voltage generator to provide a reference voltage proportional to the velocity of wind incident on the fence. An analog divider receives the first electrical signal and the reference signal as its numerator and denominator inputs, respectively, and generates therefrom an output signal which is insensitive to the wind-induced movements in the fence.

  3. Capillary Electrophoresis - Optical Detection Systems

    SciTech Connect

    Sepaniak, M. J.

    2001-08-06

    Molecular recognition systems are developed via molecular modeling and synthesis to enhance separation performance in capillary electrophoresis and optical detection methods for capillary electrophoresis. The underpinning theme of our work is the rational design and development of molecular recognition systems in chemical separations and analysis. There have been, however, some subtle and exciting shifts in our research paradigm during this period. Specifically, we have moved from mostly separations research to a good balance between separations and spectroscopic detection for separations. This shift is based on our perception that the pressing research challenges and needs in capillary electrophoresis and electrokinetic chromatography relate to the persistent detection and flow rate reproducibility limitations of these techniques (see page 1 of the accompanying Renewal Application for further discussion). In most of our work molecular recognition reagents are employed to provide selectivity and enhance performance. Also, an emerging trend is the use of these reagents with specially-prepared nano-scale materials. Although not part of our DOE BES-supported work, the modeling and synthesis of new receptors has indirectly supported the development of novel microcantilevers-based MEMS for the sensing of vapor and liquid phase analytes. This fortuitous overlap is briefly covered in this report. Several of the more significant publications that have resulted from our work are appended. To facilitate brevity we refer to these publications liberally in this progress report. Reference is also made to very recent work in the Background and Preliminary Studies Section of the Renewal Application.

  4. Effect of gamma-irradiation on serum samples on the diagnostic performance of ELISA methods for the detection of trypanosomal antibodies.

    PubMed

    Rebeski, D E; Winger, E M; Gabler, C M; Dwinger, R H; Crowther, J R

    2001-08-01

    The study investigated the effect of gamma-irradiation on bovine serum samples on the ability of enzyme-linked immunosorbent assay (ELISA) methods to detect trypanosomal antibodies. The serum samples were analysed using two standardised indirect ELISA systems. Higher measurement values were observed for most gamma-irradiated antibody positive and negative test samples. Using cut-off points, determined from the analysis of a non-irradiated trypanosomal antibody-negative population, the gamma-irradiated sera data showed that there was an increased risk of misclassifying samples as false positive or cross-reactive due to increased analytical sensitivity and decreased analytical specificity. The intraplate precision and agreement between tested and expected values of measurements were not altered throughout. The impact on the assays' diagnostic performance was estimated by analysing diagnostic sensitivity, diagnostic specificity and related parameters. The data demonstrated that although there was a bias of higher measurement values after gamma-irradiation, this could be compensated after readjustment of the cut-off points to obtain best separation of antibody-positive and -negative samples. Thus, for each assay, no significant difference of the diagnostic proficiency was found before and after gamma-irradiation. The practical implications are discussed of a serum sterilisation procedure using (60)Co gamma-rays for routine sample testing, assay validation and trypanosomosis monitoring and tsetse-fly control and eradication programmes. PMID:11470177

  5. Fish detection and classification system

    NASA Astrophysics Data System (ADS)

    Tidd, Richard A.; Wilder, Joseph

    2001-01-01

    Marine biologists traditionally determine the presence and quantities of different types of fish by dragging nets across the bottom, and examining their contents. This method, although accurate, kills the collected fish, damages their habitat, and consumes large quantities of resources. This paper presents an alternative, a machine vision system capable of determining the presence of fish species. Illumination presents a unique problem in this environment, and the design of an effective illumination system is discussed. The related issues of object orientation and measurement are also discussed and resolved. Capturing images of fish in murky water also presents challenges. An adaptive thresholding technique is required to appropriately segment the fish from the background in these images. Mode detection, and histogram analysis are useful tools in determining these localized thresholds. It is anticipated that this system, created in conjunction with the Rutgers Institute for Marine and Coastal Science, will effectively classify fish in the estuarine environment.

  6. Ionization detection system for aerosols

    DOEpatents

    Jacobs, Martin E.

    1977-01-01

    This invention relates to an improved smoke-detection system of the ionization-chamber type. In the preferred embodiment, the system utilizes a conventional detector head comprising a measuring ionization chamber, a reference ionization chamber, and a normally non-conductive gas triode for discharging when a threshold concentration of airborne particulates is present in the measuring chamber. The improved system utilizes a measuring ionization chamber which is modified to minimize false alarms and reductions in sensitivity resulting from changes in ambient temperature. In the preferred form of the modification, an annular radiation shield is mounted about the usual radiation source provided to effect ionization in the measuring chamber. The shield is supported by a bimetallic strip which flexes in response to changes in ambient temperature, moving the shield relative to the source so as to vary the radiative area of the source in a manner offsetting temperature-induced variations in the sensitivity of the chamber.

  7. Detecting fissionable materials in a variety of shielding matrices via delayed gamma and neutron photofission signatures—Part 2: Experimental results

    NASA Astrophysics Data System (ADS)

    Proctor, Alan; Gabriel, Tony A.; Hunt, Alan W.; Manges, JoAnn; Handler, Thomas

    2012-01-01

    Successful detection of fissionable material contained in a variety of matrices was demonstrated by photon active interrogation of fissionable and inert target materials. Samples were irradiated with pulsed 15 MeV photons generated by a LINAC and tungsten electron/photon converter, operating at 15 Hz. Matrix materials included air (no matrix), wood, water, and lead. A unique dual mode gamma/neutron detector was used to acquire data from both fission product gamma and fission product neutron emission. Neutron emission was recorded by detecting the 478 keV capture gamma from the 10B (n,α) 7Li reaction, generating a photopeak in the recorded gamma spectrum. Two signatures were found to correctly differentiate between the fissionable target ( 238U) and inert targets (lead, steel, air, and beryllium), with substantial differences in delayed gamma and neutron signatures for fissionable and inert materials in all cases. The signatures are simple to compute and are not significantly affected by system variations or interferences expected during cargo scanning.

  8. Use of Piezoelectric Immunosensors for Detection of Interferon-Gamma Interaction with Specific Antibodies in the Presence of Released-Active Forms of Antibodies to Interferon-Gamma.

    PubMed

    Don, Elena; Farafonova, Olga; Pokhil, Suzanna; Barykina, Darya; Nikiforova, Marina; Shulga, Darya; Borshcheva, Alena; Tarasov, Sergey; Ermolaeva, Tatyana; Epstein, Oleg

    2016-01-01

    In preliminary ELISA studies where released-active forms (RAF) of antibodies (Abs) to interferon-gamma (IFNg) were added to the antigen-antibody system, a statistically significant difference in absorbance signals obtained in their presence in comparison to placebo was observed. A piezoelectric immunosensor assay was developed to support these data and investigate the effects of RAF Abs to IFNg on the specific interaction between Abs to IFNg and IFNg. The experimental conditions were designed and optimal electrode coating, detection circumstances and suitable chaotropic agents for electrode regeneration were selected. The developed technique was found to provide high repeatability, intermediate precision and specificity. The difference between the analytical signals of RAF Ab samples and those of the placebo was up to 50.8%, whereas the difference between non-specific controls and the placebo was within 5%-6%. Thus, the piezoelectric immunosensor as well as ELISA has the potential to be used for detecting the effects of RAF Abs to IFNg on the antigen-antibody interaction, which might be the result of RAF's ability to modify the affinity of IFNg to specific/related Abs. PMID:26791304

  9. Use of Piezoelectric Immunosensors for Detection of Interferon-Gamma Interaction with Specific Antibodies in the Presence of Released-Active Forms of Antibodies to Interferon-Gamma

    PubMed Central

    Don, Elena; Farafonova, Olga; Pokhil, Suzanna; Barykina, Darya; Nikiforova, Marina; Shulga, Darya; Borshcheva, Alena; Tarasov, Sergey; Ermolaeva, Tatyana; Epstein, Oleg

    2016-01-01

    In preliminary ELISA studies where released-active forms (RAF) of antibodies (Abs) to interferon-gamma (IFNg) were added to the antigen-antibody system, a statistically significant difference in absorbance signals obtained in their presence in comparison to placebo was observed. A piezoelectric immunosensor assay was developed to support these data and investigate the effects of RAF Abs to IFNg on the specific interaction between Abs to IFNg and IFNg. The experimental conditions were designed and optimal electrode coating, detection circumstances and suitable chaotropic agents for electrode regeneration were selected. The developed technique was found to provide high repeatability, intermediate precision and specificity. The difference between the analytical signals of RAF Ab samples and those of the placebo was up to 50.8%, whereas the difference between non-specific controls and the placebo was within 5%–6%. Thus, the piezoelectric immunosensor as well as ELISA has the potential to be used for detecting the effects of RAF Abs to IFNg on the antigen-antibody interaction, which might be the result of RAF’s ability to modify the affinity of IFNg to specific/related Abs. PMID:26791304

  10. Automatic optimisation of gamma dose rate sensor networks: The DETECT Optimisation Tool

    NASA Astrophysics Data System (ADS)

    Helle, K. B.; Müller, T. O.; Astrup, P.; Dyve, J. E.

    2014-05-01

    Fast delivery of comprehensive information on the radiological situation is essential for decision-making in nuclear emergencies. Most national radiological agencies in Europe employ gamma dose rate sensor networks to monitor radioactive pollution of the atmosphere. Sensor locations were often chosen using regular grids or according to administrative constraints. Nowadays, however, the choice can be based on more realistic risk assessment, as it is possible to simulate potential radioactive plumes. To support sensor planning, we developed the DETECT Optimisation Tool (DOT) within the scope of the EU FP 7 project DETECT. It evaluates the gamma dose rates that a proposed set of sensors might measure in an emergency and uses this information to optimise the sensor locations. The gamma dose rates are taken from a comprehensive library of simulations of atmospheric radioactive plumes from 64 source locations. These simulations cover the whole European Union, so the DOT allows evaluation and optimisation of sensor networks for all EU countries, as well as evaluation of fencing sensors around possible sources. Users can choose from seven cost functions to evaluate the capability of a given monitoring network for early detection of radioactive plumes or for the creation of dose maps. The DOT is implemented as a stand-alone easy-to-use JAVA-based application with a graphical user interface and an R backend. Users can run evaluations and optimisations, and display, store and download the results. The DOT runs on a server and can be accessed via common web browsers; it can also be installed locally.

  11. Terrestrial Gamma-Ray Flashes at the highest energies as detected by AGILE

    NASA Astrophysics Data System (ADS)

    Tavani, M.; Marisaldi, M.; Fuschino, F.; Labanti, C.; Argan, A.; Agile Team

    2011-12-01

    The AGILE satellite, operating since mid-2007, is ideal for the study of Terrestrial Gamma-Ray Flashes (TGFs) at the highest energies. AGILE has been detecting TGFs with both its Calorimeter and with its imaging gamma-ray Tracker. The on-board trigger logic has a broad dynamic range (reaching sub-millisecond trigger timescales) and a detection capability in the range 0.3 - 100 MeV. Since the 2009-2010 discovery of a power-law spectral component surprisingly detected up to 100 MeV, AGILE has been collecting additional TGF data with a substantial improvement of the statistics. We will present the most recent results based on about 300 events, focusing on the properties of TGFs showing substantial emission above 40 MeV (High-Energy TGF, HE-TGFs). We will also present new results on the global and local correlation between the TGFs/HE-TGFs and the lightning activity in the equatorial region as obtained by LIS/OTD data. Theoretical implications of HE-TGFs on particle acceleration in thunderstorms will be discussed as well as the possible important impacts of HE-TGFs in the atmospheric environment. The atmosphere during severe thunderstorms becomes a most efficient particle accelerator on Earth, challenging current models of TGF production.

  12. Detection of a flaring low-energy gamma-ray source

    NASA Technical Reports Server (NTRS)

    Bhattacharya, Dipen; Owens, Alan

    1994-01-01

    We report the detection of a flaring gamma-ray source by the University of New Hampshire (UNH) balloon-borne coded aperture gamma-ray telescope (DGT) on 1984 October 2. The source was detected at the significance level of 7.2 sigma over the energy range 160-2000 keV. The intensity in the range (160-200) keV was 1.1 Crab. The best-fit position of the source is given by R.A. = 3h 25.8m and Decl. = 67 deg 653 min and is located in the constellation of Camelopardia. The source was visible within the Field of View (FOV) of the telescope for approximately = 2 hr and exhibited signs of flaring. The derived photon spectrum can be equally fitted by an optically thin bremsstrahlung distribution of kT approximately = 52 keV or a power law of the form, dN(E)/dE = 3.7 x 10(exp -6) (E/400)(exp -4.5) photons/sq cm/keV. We compare its spectral characteristics ad energy output to various types of fast X-ray transients. No measurable flux could be detected from CG 135+1, the COS B source which was in the FOV and therefore, we present 2 sigma upper flux limits on its spectral emission over the energy range 160 keV to 9.3 MeV.

  13. A Mobile Automated Tomographic Gamma Scanning System - 13231

    SciTech Connect

    Kirkpatrick, J.M.; LeBlanc, P.J.; Nakazawa, D.; Petroka, D.L.; Kane Smith, S.; Venkataraman, R.; Villani, M.

    2013-07-01

    Canberra Industries have recently designed and built a new automated Tomographic Gamma Scanning (TGS) system for mobile deployment. The TGS technique combines high-resolution gamma spectroscopy with low spatial resolution 3-dimensional image reconstruction to provide increased accuracy over traditional approaches for the assay of non-uniform source distributions in low-to medium-density, non-heterogeneous matrices. Originally pioneered by R. Estep at Los Alamos National Laboratory (LANL), the TGS method has been further developed and commercialized by Canberra Industries in recent years. The present system advances the state of the art on several fronts: it is designed to be housed in a standard cargo transport container for ease of transport, allowing waste characterization at multiple facilities under the purview of a single operator. Conveyor feed, drum rotator, and detector and collimator positioning mechanisms operated by programmable logic control (PLC) allow automated batch mode operation. The variable geometry settings can accommodate a wide range of waste packaging, including but not limited to standard 220 liter drums, 380 liter overpack drums, and smaller 20 liter cans. A 20 mCi Eu-152 transmission source provides attenuation corrections for drum matrices up to 1 g/cm{sup 3} in TGS mode; the system can be operated in Segmented Gamma Scanning (SGS) mode to measure higher density drums. To support TGS assays at higher densities, the source shield is sufficient to house an alternate Co-60 transmission source of higher activity, up to 250 mCi. An automated shutter and attenuator assembly is provided for operating the system with a dual intensity transmission source. The system's 1500 kg capacity rotator turntable can handle heavy containers such as concrete lined 380 liter overpack drums. Finally, data acquisition utilizes Canberra's Broad Energy Germanium (BEGE) detector and Lynx MCA, with 32 k channels, providing better than 0.1 keV/channel resolution to

  14. MeV Gamma Ray Detection Algorithms for Stacked Silicon Detectors

    NASA Technical Reports Server (NTRS)

    McMurray, Robert E. Jr.; Hubbard, G. Scott; Wercinski, Paul F.; Keller, Robert G.

    1993-01-01

    By making use of the signature of a gamma ray event as it appears in N = 5 to 20 lithium-drifted silicon detectors and applying smart selection algorithms, gamma rays in the energy range of 1 to 8 MeV can be detected with good efficiency and selectivity. Examples of the types of algorithms used for different energy regions include the simple sum mode, the sum-coincidence mode used in segmented detectors, unique variations on sum-coincidence for an N-dimensional vector event, and a new and extremely useful mode for double escape peak spectroscopy at pair-production energies. The latter algorithm yields a spectrum similar to that of the pair spectrometer, but without the need of the dual external segments for double escape coincidence, and without the large loss in efficiency of double escape events. Background events due to Compton scattering are largely suppressed. Monte Carlo calculations were used to model the gamma ray interactions in the silicon, in order to enable testing of a wide array of different algorithms on the event N-vectors for a large-N stack.

  15. Technical Aspects of a Germanium Calorimeter for Space-BorneGamma-Ray Detection

    SciTech Connect

    Crawford, H.; Smoot, G.

    1988-06-01

    Our scientific objective is to search for high energy annihilation lines from dark matter candidate particles and to measure the diffuse {gamma}-ray spectrum as a probe of cosmological distances and volumes. To pursue this objective we need a detector that has good energy resolution, better than 1% at 3 GeV. Such resolution is required to identify {gamma}-ray lines which are separated by {approx} hundred MeV at energies of a few Gev and to separate these lines from the continuum background produced by high galactic latitude cosmic ray collisions. The detector must be able to locate or map sources. The directional accuracy required for pointing to the galactic center or to known pulsars is on the order of l{sup o} (16mrad) or better. To avoid degradation of signal by the atmosphere, the detector must be flown in space. The expected signal is low, suggesting that an exposure of something like 1 m{sup 2}-yr is required to gather a statistically significant number of events. In this document we will look at alternative methods for detection of high energy {gamma}-ray lines in space and argue that a fully active Ge volume is the optimum detector that can be built.

  16. Imaging system for cardiac planar imaging using a dedicated dual-head gamma camera

    SciTech Connect

    Majewski, Stanislaw; Umeno, Marc M.

    2011-09-13

    A cardiac imaging system employing dual gamma imaging heads co-registered with one another to provide two dynamic simultaneous views of the heart sector of a patient torso. A first gamma imaging head is positioned in a first orientation with respect to the heart sector and a second gamma imaging head is positioned in a second orientation with respect to the heart sector. An adjustment arrangement is capable of adjusting the distance between the separate imaging heads and the angle between the heads. With the angle between the imaging heads set to 180 degrees and operating in a range of 140-159 keV and at a rate of up to 500kHz, the imaging heads are co-registered to produce simultaneous dynamic recording of two stereotactic views of the heart. The use of co-registered imaging heads maximizes the uniformity of detection sensitivity of blood flow in and around the heart over the whole heart volume and minimizes radiation absorption effects. A normalization/image fusion technique is implemented pixel-by-corresponding pixel to increase signal for any cardiac region viewed in two images obtained from the two opposed detector heads for the same time bin. The imaging system is capable of producing enhanced first pass studies, bloodpool studies including planar, gated and non-gated EKG studies, planar EKG perfusion studies, and planar hot spot imaging.

  17. A gamma-ray flare from 3C 454.3 detected by AGILE

    NASA Astrophysics Data System (ADS)

    Munar-Adrover, P.; Piano, G.; Pittori, C.; Verrecchia, F.; Lucarelli, F.; Bulgarelli, A.; Parmiggiani, N.; Fioretti, V.; Zoli, A.; Vercellone, S.; Tavani, M.; Donnarumma, I.; Striani, E.; Minervini, G.; Cardillo, M.; Gianotti, F.; Trifoglio, M.; Giuliani, A.; Mereghetti, S.; Caraveo, P.; Perotti, F.; Chen, A.; Argan, A.; Costa, E.; Del Monte, E.; Evangelista, Y.; Feroci, M.; Lazzarotto, F.; Lapshov, I.; Pacciani, L.; Soffitta, P.; Sabatini, S.; Vittorini, V.; Pucella, G.; Rapisarda, M.; Di Cocco, G.; Fuschino, F.; Galli, M.; Labanti, C.; Marisaldi, M.; Pellizzoni, A.; Pilia, M.; Trois, A.; Barbiellini, G.; Vallazza, E.; Longo, F.; Morselli, A.; Picozza, P.; Prest, M.; Lipari, P.; Zanello, D.; Cattaneo, P. W.; Rappoldi, A.; Colafrancesco, S.; Ferrari, A.; Antonelli, A.; Giommi, P.; Salotti, L.; Valentini, G.; D'Amico, F.

    2016-06-01

    The AGILE satellite is detecting a significant enhancement in gamma-ray activity from the FSRQ 3C 454.3 since the recent ATel #9176. According to a maximum likelihood analysis of the AGILE-GRID data for the integration period between 2016-06-22 02:50:00 UT and 2016-06-24 02:50:00 UT, the flux is F(E > 100 MeV) = (1.2 +/- 0.2) x 10^-5 ph/cm^2/s; this corresponds to a flux increase of approximately a factor of 6 above the average flux during the last 6 days.

  18. Pulsed helium ionization detection system

    DOEpatents

    Ramsey, Roswitha S.; Todd, Richard A.

    1987-01-01

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  19. Pulsed helium ionization detection system

    DOEpatents

    Ramsey, R.S.; Todd, R.A.

    1985-04-09

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  20. Gamma emission tomosynthesis based on an automated slant hole collimation system

    NASA Astrophysics Data System (ADS)

    Pellegrini, R.; Pani, R.; Cinti, M. N.; Longo, M.; Lo Meo, S.; Viviano, M.

    2015-03-01

    The imaging capabilities of radioisotope molecular imaging systems are limited by their ring geometry and by the object-to-detector distance, which impairs spatial resolution, efficiency and image quality. These detection capabilities could be enhanced by performing acquisitions with dedicated gamma cameras placed in close proximity to the object that has to be examined. The main aim of this work is to develop a compact camera suitable for detecting small and low-contrast lesions, with a higher detection efficiency than conventional SPECT, through a gamma emission tomosynthesis method. In this contribution a prototype of a new automated slant hole collimator, coupled to a small Field of View (FoV) gamma camera, is presented. The proposed device is able to acquire planar projection images at different angles without rotating around the patient body; these projection images are then three-dimensional reconstructed. Therefore, in order to perform the volumetric reconstruction of the studied object, the traditional Back Projection (BP) reconstruction is compared with the Shift And Add (SAA) method. In order to verify the effectiveness of the technique and to test the image reconstruction algorithms, a Monte Carlo simulation, based on the GEANT4 code, was implemented. The method was also validated by a set of experimental measurements. The discussed device is designed to work in patient proximity for detecting lesions placed at a distances ranged from 0 to 8 cm, thus allowing few millimeters planar resolutions and sagittal resolution of about 2 cm. The new collimation method implies high-resolution capabilities demonstrated by reconstructing the projection images through the BP and the SAA methods. The latter is simpler than BP and produces comparable spatial resolutions with respect to the traditional tomographic method, while preserving the image counts.

  1. Infrared trace element detection system

    DOEpatents

    Bien, Fritz; Bernstein, Lawrence S.; Matthew, Michael W.

    1988-01-01

    An infrared trace element detection system including an optical cell into which the sample fluid to be examined is introduced and removed. Also introduced into the optical cell is a sample beam of infrared radiation in a first wavelength band which is significantly absorbed by the trace element and a second wavelength band which is not significantly absorbed by the trace element for passage through the optical cell through the sample fluid. The output intensities of the sample beam of radiation are selectively detected in the first and second wavelength bands. The intensities of a reference beam of the radiation are similarly detected in the first and second wavelength bands. The sensed output intensity of the sample beam in one of the first and second wavelength bands is normalized with respect to the other and similarly, the intensity of the reference beam of radiation in one of the first and second wavelength bands is normalized with respect to the other. The normalized sample beam intensity and normalized reference beam intensity are then compared to provide a signal from which the amount of trace element in the sample fluid can be determined.

  2. Infrared trace element detection system

    DOEpatents

    Bien, F.; Bernstein, L.S.; Matthew, M.W.

    1988-11-15

    An infrared trace element detection system includes an optical cell into which the sample fluid to be examined is introduced and removed. Also introduced into the optical cell is a sample beam of infrared radiation in a first wavelength band which is significantly absorbed by the trace element and a second wavelength band which is not significantly absorbed by the trace element for passage through the optical cell through the sample fluid. The output intensities of the sample beam of radiation are selectively detected in the first and second wavelength bands. The intensities of a reference beam of the radiation are similarly detected in the first and second wavelength bands. The sensed output intensity of the sample beam in one of the first and second wavelength bands is normalized with respect to the other and similarly, the intensity of the reference beam of radiation in one of the first and second wavelength bands is normalized with respect to the other. The normalized sample beam intensity and normalized reference beam intensity are then compared to provide a signal from which the amount of trace element in the sample fluid can be determined. 11 figs.

  3. [A multi-phase flow detector system based on gamma-ray].

    PubMed

    Ma, Min; Wang, Hua-xiang; Hao, Kui-hong

    2010-07-01

    In the present paper, a gamma-ray based on-line detection system was designed for multi-phase flow measurement, where the complicated fluid property of multi-phase flow can be studied by using the principle of ray transmission. The system is made up of three parts, i. e., the sensing unit, the signal conditioning & processing unit and the computer imaging unit. The sensing unit consists of five 241 Am sources with principal energy of 59.5 keV and five sets of CdZnTe semiconductor detectors by using the Geant 4 simulating software toolkits. The sources and detectors are mounted equally at the cross section of pipeline to detect different phase medium simultaneously. This function of the system guarantees the real-time performance of the on-line detecting. In order to improve the accuracy of the probe, a low noise probe circuit was designed, including a low noise charge-sensitive preamplifier, a low noise amplifier, filter circuit and an eliminated zero-poles circuit. Some of the emitted gamma-ray photons from the radiation sources are detected by the sensing element, where the photo energy is transferred into electrical energy by using CdZnTe semiconductor detectors. The output of the sensing element is sent to the signal conditioning & processing unit, which is amplified and filtered to be a level-discriminated signal. Finally, the output of the signal conditioning & processing unit is sent to the computer imaging unit, in which the 2D images are reconstructed by using a certain reconstruction algorithm. Under the normal temperature, the system performs the test of energy spectrum and then it has better energy resolution about 4.38% for 241 Am 59.5 keV. The result reveals that our system has higher probe accuracy. Using experimental data, the images are reconstructed with Filter back projection (FBP) reconstruction algorithm. Images of high quality are achieved. PMID:20828018

  4. Detection of high-energy gamma rays from quasar PKS 0528 + 134 by EGRET on the Compton Gamma Ray Observatory

    NASA Technical Reports Server (NTRS)

    Hunter, S. D.; Bertsch, D. L.; Dingus, B. L.; Fichtel, C. E.; Hartman, R. C.; Kanbach, G.; Kniffen, D. A.; Kwok, P. W.; Lin, Y. C.; Mattox, J. R.

    1993-01-01

    The first several pointing directions of the Compton Gamma Ray Observatory, launched on 1991 April 5, were toward the Galactic anticenter. In addition to the known gamma-ray sources, Crab and Geminga, high-energy gamma-ray emission was observed from the quasar PKS 0528 + 134 by the Energetic Gamma Ray Experiment Telescope (EGRET). A redshift measurement, reported here, of 2.07 confirms the identification of this object as a quasar. The differential photon spectrum is well represented by a power law with an exponent of 2.56 +/- 0.09 and a photon intensity above 100 MeV of (8.4 +/- 1.0) x 10 exp -7 photons sq cm/s. There is evidence for time variability on a time scale of a few days.

  5. System and method for resolving gamma-ray spectra

    DOEpatents

    Gentile, Charles A.; Perry, Jason; Langish, Stephen W.; Silber, Kenneth; Davis, William M.; Mastrovito, Dana

    2010-05-04

    A system for identifying radionuclide emissions is described. The system includes at least one processor for processing output signals from a radionuclide detecting device, at least one training algorithm run by the at least one processor for analyzing data derived from at least one set of known sample data from the output signals, at least one classification algorithm derived from the training algorithm for classifying unknown sample data, wherein the at least one training algorithm analyzes the at least one sample data set to derive at least one rule used by said classification algorithm for identifying at least one radionuclide emission detected by the detecting device.

  6. Monte Carlo simulation of a PhosWatch detector using Geant4 for xenon isotope beta-gamma coincidence spectrum profile and detection efficiency calculations.

    PubMed

    Mekarski, P; Zhang, W; Ungar, K; Bean, M; Korpach, E

    2009-10-01

    A simulation tool has been developed using the Geant4 Toolkit to simulate a PhosWatch single channel beta-gamma coincidence detection system consisting of a CsI(Tl)/BC404 Phoswich well detector and pulse shape analysis algorithms implemented digital signal processor. The tool can be used to simulate the detector's response for all the gamma rays and beta particles emitted from (135)Xe, (133m)Xe, (133)Xe, (131m)Xe and (214)Pb. Two- and three-dimensional beta-gamma coincidence spectra from the PhosWatch detector can be produced using the simulation tool. The accurately simulated spectra could be used to calculate system coincidence detection efficiency for each xenon isotope, the corrections for the interference from the various spectral components from radon and xenon isotopes, and system gain calibration. Also, it can generate two- and three-dimensional xenon reference spectra to test beta-gamma coincidence spectral deconvolution analysis software. PMID:19647444

  7. Gamma-ray and neutron radiography for a pulsed fast- neutron analysis cargo inspection system

    NASA Astrophysics Data System (ADS)

    Rynes, Joel Christian

    1999-11-01

    This dissertation presents the design, optimization, and characterization of a gamma-ray and neutron radiographic subsystem that was developed for the Pulsed Fast Neutron Analysis (PFNA) cargo inspection system. The PFNA inspection system uses nanosecond pulsed neutrons to produce three-dimensional elemental density images of cargo. Contraband in the cargo can be detected by its elemental content. The PFNA neutron source produces gamma rays as well as neutrons. The radiographic subsystem measures these radiations in an array of plastic scintillators to produce gamma-ray and neutron transmission images of the cargo simultaneously with the PFNA measurement. Although the radiographic subsystem improves PFNA performance in many forms of contraband detection, it was specifically designed to detect Special Nuclear Material (SNM) in cargo containers and trucks. A feasibility study, including experiments and modeling, was performed to determine the usefulness of gamma-ray radiography in this application. The study assumed a baseline configuration of the PFNA source, a relatively small rectangular radiation beam, and a plastic detector with a 5.1 cm diameter and a 7.6 cm length. The study showed that the baseline configuration was useful in cargoes up to 144 g/cm2 thick. At this thickness, a signal-to-noise ratio of three was obtainable per pixel. The maximum cargo thickness was later increased to 180 g/cm2 by increasing the detector length to 17.0 cm and by changing the source beam stop from gold to copper. An experiment was then performed that determined a 3.5 cm radiographic resolution was adequate for SNM detection. The detector configuration and the source motion were optimized to obtain a resolution of approximately 3.5 cm using the minimal number of detectors and the maximum detector diameter. The source is moved up and down as the cargo is pulled through the system to irradiate the entire surface of the cargo with the radiation beam. The final design consisted of

  8. Evaluation of Intrusion Detection Systems

    PubMed Central

    Ulvila, Jacob W.; Gaffney, John E.

    2003-01-01

    This paper presents a comprehensive method for evaluating intrusion detection systems (IDSs). It integrates and extends ROC (receiver operating characteristic) and cost analysis methods to provide an expected cost metric. Results are given for determining the optimal operation of an IDS based on this expected cost metric. Results are given for the operation of a single IDS and for a combination of two IDSs. The method is illustrated for: 1) determining the best operating point for a single and double IDS based on the costs of mistakes and the hostility of the operating environment as represented in the prior probability of intrusion and 2) evaluating single and double IDSs on the basis of expected cost. A method is also described for representing a compound IDS as an equivalent single IDS. Results are presented from the point of view of a system administrator, but they apply equally to designers of IDSs.

  9. Possible gamma-ray burst radio detections by the Square Kilometre Array. New perspectives

    NASA Astrophysics Data System (ADS)

    Ruggeri, Alan Cosimo; Capozziello, Salvatore

    2016-09-01

    The next generation interferometric radio telescope, the Square Kilometre Array (SKA), which will be the most sensitive and largest radio telescope ever constructed, could greatly contribute to the detection, survey and characterization of Gamma Ray Bursts (GRBs). By the SKA, it will be possible to perform the follow up of GRBs even for several months. This approach would be extremely useful to extend the Spectrum Energetic Distribution (SED) from the gamma to the to radio band and would increase the number of radio detectable GRBs. In principle, the SKA could help to understand the physics of GRBs by setting constraints on theoretical models. This goal could be achieved by taking into account multiple observations at different wavelengths in order to obtain a deeper insight of the sources. Here, we present an estimation of GRB radio detections, showing that the GRBs can really be observed by the SKA. The approach that we present consists in determining blind detection rates derived by a very large sample consisting of merging several GRB catalogues observed by current missions as Swift, Fermi, Agile and INTEGRAL and by previous missions as BeppoSAX, CGRO, GRANAT, HETE-2, Ulysses and Wind. The final catalogue counts 7516 distinct sources. We compute the fraction of GRBs that could be observed by the SKA at high and low frequencies, above its observable sky. Considering the planned SKA sensitivity and through an extrapolation based on previous works and observations, we deduce the minimum fluence in the range 15-150 keV. This is the energy interval where a GRB should emit to be detectable in the radio band by the SKA. Results seem consistent with observational capabilities.

  10. BurstCube: A Gamma-ray Burst Detecting Swarm of CubeSats

    NASA Astrophysics Data System (ADS)

    Perkins, Jeremy S; Racusin, Judith L.; Krizmanic, John F; McEnery, Julie E.

    2014-08-01

    The study of gamma-ray bursts (GRBs) has seen major advances in the past decade based on the results of several highly successful missions like Swift and Fermi. These prolific GRB detectors have enabled multi-wavelength follow-up of hundreds of GRBs and have allowed us to answer some of the outstanding questions in this field as well as prompted research in many new directions. It is critical to continue GRB detection, especially with gravitational wave detectors coming online in the next few years, e.g. advanced LIGO/Virgo, and the continued operation of multi-messenger observatories such as IceCube. Without the detection and study of counterparts to these future non-photon detections, the full characterization of a GRB would be difficult. The current GRB detection technology is at a mature level such that small, inexpensive detectors on CubeSats could perform as well or better than the current generation of GRB scintillator detectors. This paper will detail the design parameters and performance of small, GRB detecting CubeSats operating in a swarm that can detect, localize, and characterize GRBs via the high energy photon signatures.

  11. Recent advances in microfluidic detection systems

    PubMed Central

    Baker, Christopher A; Duong, Cindy T; Grimley, Alix; Roper, Michael G

    2009-01-01

    There are numerous detection methods available for methods are being put to use for detection on these miniaturized systems, with the analyte of interest driving the choice of detection method. In this article, we summarize microfluidic 2 years. More focus is given to unconventional approaches to detection routes and novel strategies for performing high-sensitivity detection. PMID:20414455

  12. Software for Control and Measuring Instrumentation of the GAMMA-400 Gamma-telescope Fast Scintillator Detector System

    NASA Astrophysics Data System (ADS)

    Naumov, P. P.; Naumov, P. Yu.; Runtso, M. F.; Solodovnikov, A. A.

    Currently, the final stage of the ground tests for the technological detector of the high-energy gamma-ray telescope (GRT) GAMMA-400 are finished. The new space GRT will accept the gamma-rays with energy more than 400 MeV and is aimed to open our eyes for so-called "dark matter" problem in the Universe. The high-speed scintillation detectors system (SDS) is used one of the main GRT particle detectors and the good ground test measurements will let the future space mission to get the reliable data. This paper describes the software and hardware of the laboratory control and calibration systems for physical measurements of GRT STDS properties.

  13. Medical isotope identification with large mobile detection systems

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sanjoy; Maurer, Richard

    2012-10-01

    The Remote Sensing laboratory (RSL) of National Security Technologies Inc. has built an array of large (5.08 - cm x 10.16 - cm x 40.6 - cm) thallium doped sodium iodide (NaI: Tl) scintillators to locate and screen gamma-ray emitting radioisotopes that are of interests to radiological emergency responders [1]. These vehicle mounted detectors provide the operators with rapid, simple, specific information for radiological threat assessment. Applications include large area inspection, customs inspection, border protection, emergency response, and monitoring of radiological facilities. These RSL mobile units are currently being upgraded to meet the Defense Threat Reduction Agency mission requirements for a next-generation system capable of detecting and identifying nuclear threat materials. One of the challenging problems faced by these gamma-ray detectors is the unambiguous identification of medical isotopes like 131I (364.49 keV [81.7%], 636.99 keV [7.17%]), 99Tcm (140.51 keV [89.1%]) and 67Ga (184.6 keV [19.7%], 300.2 [16.0%], 393.5 [4.5%] that are used in radionuclide therapy and often have overlapping gamma-ray energy regions of interest (ROI). The problem is made worse by short (about 5 seconds) acquisition time of the spectral data necessary for dynamic mobile detectors. This article describes attempts to identify medical isotopes from data collected from this mobile detection system in a short period of time (not exceeding 5 secs) and a large standoff distance (typically ~ 10 meters) The mobile units offer identification capabilities that are based on hardware auto stabilization of the amplifier gain. The 1461 keV gamma-energy line from 40K is tracked. It uses gamma-ray energy windowing along with embedded mobile Gamma Detector Response and Analysis Software (GADRAS) [2] simultaneously to deconvolve any overlapping gamma-energy ROIs. These high sensitivity detectors are capable of resolving complex masking scenarios and exceed all ANSI N42.34 (2006) requirements

  14. Detection of Anomalous Gamma-Ray Spectra for On-Site Inspection

    SciTech Connect

    Seifert, Carolyn E.; Myjak, Mitchell J.; Pfund, David M.

    2009-05-29

    This work aims to solve some of the technical and logistical challenges inherent in performing On Site Inspection activities under the authority of the Comprehensive Nuclear-Test-Ban Treaty. Inspectors require equipment that can reliably identify the radionuclide signatures of nuclear test explosions amid a background of environmental contamination. Detection of these radiation anomalies by mobile search teams in the air or on the ground can narrow the search field and target specific areas for more detailed inspection or sampling. The need to protect confidential information of the inspected State Party, especially regarding past nuclear testing activities, suggests that full access to measured gamma-ray spectra should be limited. Spectral blinding techniques---in which only a fraction of the information derived from the spectra is displayed and stored---have the potential to meet the needs of both the OSI team and the State Party. In this paper, we describe one such algorithm that we have developed for identifying anomalous spectra from handheld, mobile, or aerial sensors. The algorithm avoids potential sensitivities by reducing the gamma-ray spectrum into a single number that is displayed and stored. A high value indicates that the spectrum is anomalous. The proposed technique does not rely on identifying specific radionuclides, operates well in the presence of high background variability, and can be configured to ignore specific spectral components. In previous work, the algorithm has proven very effective in classifying gamma-ray spectra as anomalous or not, even with poor statistical information. We performed a limited simulation of an airborne search scenario to demonstrate the potential algorithm for OSI missions. The technique successfully detected an injected source of interest whose count rate was an order of magnitude below background levels. We also configured the algorithm to ignore 137Cs as irrelevant to the mission. The resulting alarm metrics were

  15. Modeling and Maximum Likelihood Fitting of Gamma-Ray and Radio Light Curves of Millisecond Pulsars Detected with Fermi

    NASA Technical Reports Server (NTRS)

    Johnson, T. J.; Harding, A. K.; Venter, C.

    2012-01-01

    Pulsed gamma rays have been detected with the Fermi Large Area Telescope (LAT) from more than 20 millisecond pulsars (MSPs), some of which were discovered in radio observations of bright, unassociated LAT sources. We have fit the radio and gamma-ray light curves of 19 LAT-detected MSPs in the context of geometric, outermagnetospheric emission models assuming the retarded vacuum dipole magnetic field using a Markov chain Monte Carlo maximum likelihood technique. We find that, in many cases, the models are able to reproduce the observed light curves well and provide constraints on the viewing geometries that are in agreement with those from radio polarization measurements. Additionally, for some MSPs we constrain the altitudes of both the gamma-ray and radio emission regions. The best-fit magnetic inclination angles are found to cover a broader range than those of non-recycled gamma-ray pulsars.

  16. A high temperature transfer procedure for detection of G protein gamma subunits by immunoblotting.

    PubMed

    Robishaw, J D; Balcueva, E A

    1993-02-01

    The production of antibodies against synthetic peptides derived from amino acid sequences common or unique to a particular protein(s) is an important tool in the identification of structurally related members of an ever-increasing number of protein families. The successful use of anti-peptide antibodies requires that the protein(s) of interest be properly transferred and fully denatured prior to detection by Western-type immunoblotting. In this paper, we demonstrate that conventional transfer procedures are not successful in presenting the G protein gamma subunits in a suitable state for immunodetection. We describe a high temperature (70 degrees C) transfer procedure that results in a more than 20-fold enhancement in the sensitivity of immunodetection of the various G protein gamma subunits. The effect of high temperature transfer could not be duplicated by including 0.2% SDS in the buffer during transfer to nitrocellulose, or by baking or autoclaving the nitrocellulose after transfer. Thus, high temperature transfer is a powerful procedure for enhancing immunoblot detection of protein(s) that may be resistant to denaturation and/or subject to renaturation during the transfer and/or binding to nitrocellulose. PMID:7680843

  17. Improved methods for detecting gravitational waves associated with short gamma-ray bursts

    NASA Astrophysics Data System (ADS)

    Williamson, A. R.; Biwer, C.; Fairhurst, S.; Harry, I. W.; Macdonald, E.; Macleod, D.; Predoi, V.

    2014-12-01

    In the era of second generation ground-based gravitational wave detectors, short gamma-ray bursts (GRBs) will be among the most promising astrophysical events for joint electromagnetic and gravitational wave observation. A targeted, coherent search for gravitational wave compact binary merger signals in coincidence with short GRBs was developed and used to analyze data from the first generation LIGO and Virgo instruments. In this paper, we present improvements to this search that enhance our ability to detect gravitational wave counterparts to short GRBs. Specifically, we introduce an improved method for estimating the gravitational wave background to obtain the event significance required to make detections; implement a method of tiling extended sky regions, as required when searching for signals associated to poorly localized GRBs from the Fermi Gamma-ray Burst Monitor or the InterPlanetary Network; and incorporate astrophysical knowledge about the beaming of GRB emission to restrict the search parameter space. We describe the implementation of these enhancements and demonstrate how they improve the ability to observe binary merger gravitational wave signals associated with short GRBs. A targeted, coherent GRB search provides a 25% increase in distance sensitivity, or a doubling of the event rate, for well-localized GRBs when compared with a nontargeted, coincident analysis.

  18. FY06 Annual Report: Amorphous Semiconductors for Gamma Radiation Detection (ASGRAD)

    SciTech Connect

    Johnson, Bradley R.; Riley, Brian J.; Crum, Jarrod V.; Sundaram, S. K.; Henager, Charles H.; Zhang, Yanwen; Shutthanandan, V.

    2007-01-01

    We describe progress in the development of new materials for portable, room-temperature, gamma-radiation detection at Pacific Northwest National Laboratory at the Hanford Site in Washington State. High Z, high resistivity, amorphous semiconductors are being designed for use as solid-state detectors at near ambient temperatures; principles of operation are analogous to single-crystal semiconducting detectors. Amorphous semiconductors have both advantages and disadvantages compared to single crystals, and this project is developing methods to mitigate technical problems and design optimized material for gamma detection. Several issues involved in the fabrication of amorphous semiconductors are described, including reaction thermodynamics and kinetics, the development of pyrolytic coating, and the synthesis of ingots. The characterization of amorphous semiconductors is described, including sectioning and polishing protocols, optical microscopy, X-ray diffraction, scanning electron microscopy, optical spectroscopy, particle-induced X-ram emission, Rutherford backscattering, and electrical testing. Then collaboration with the University of Illinois at Urbana-Champaign is discussed in the areas of Hall-effect measurements and current voltage data. Finally, we discuss the strategy for continuing the program.

  19. The 52 Brightest and Hardest GRBs Detected with the Gamma-ray Burst Monitor on Fermi

    NASA Astrophysics Data System (ADS)

    Bissaldi, Elisabetta

    2011-08-01

    We present our results of the temporal and spectral analysis of a sample of 52 bright and hard gamma-ray bursts (GRBs) observed with the Fermi Gamma-ray Burst Monitor (GBM) during its first year of operation (July 2008-July 2009). Our sample was selected from a total of 253 GBM GRBs based on the event peak count rate measured between 0.2 and 40 MeV. The final sample comprised 34 long and 18 short GRBs. A first by-product of our selection methodology is the determination of a detection threshold from the GBM data alone, above which GRBs most likely will be detected in the MeV/GeV range with the Large Area Telescope (LAT) onboard Fermi. This predictor will be very useful for future multiwavelength GRB follow ups with ground and space based observatories. Further we have estimated the burst durations up to 10 MeV and for the first time expanded the duration-energy relationship in the GRB light curves to high energies. Finally, we performed time-integrated spectral analysis of all 52 bursts and compared their spectral parameters with those obtained with the larger data sample of the BATSE data. We find that the two parameter data sets are similar and confirm that short GRBs are in general harder than longer ones.

  20. Detection of short-term response of the low ionosphere on gamma ray bursts

    NASA Astrophysics Data System (ADS)

    Nina, Aleksandra; Simić, Saša.; Srećković, Vladimir A.; Popović, Luka Č.

    2015-10-01

    In this paper, we study the possibility of detection of short-term terrestrial lower ionospheric response to gamma ray bursts (GRBs) using a statistical analysis of perturbations of six very low or low-frequency (VLF/LF) radio signals emitted by transmitters located worldwide and recorded by VLF/LF receiver located in Belgrade (Serbia). We consider a sample of 54 short-lasting GRBs (shorter than 1 min) detected by the Swift satellite during the period 2009-2012. We find that a statistically significant perturbation can be present in the low ionosphere, and reactions on GRBs may be observed immediately after the beginning of the GRB event or with a time delay of 60 s-90 s.

  1. Detection of frozen salt in pipes using gamma-ray spectrometry of potassium self-activity

    SciTech Connect

    Grena, Roberto; Scafe, Raffaele; Pisacane, Fabrizio; Pilato, Renzo; Crescenzi, Tommaso; Mazzei, Domenico

    2010-01-15

    Solar plants that use molten salts as heat transfer fluid need careful control to avoid the freezing of the salt in the pipes; if such a problem occurs, a diagnostic instrument to localize where is the frozen salt plug and to determine its length is useful. If the salt contains potassium (as is the case of the most common mixture used in solar plants, NaNO{sub 3}/KNO{sub 3} 60/40% by weight), the gamma decay of the natural unstable isotope {sup 40}K can be exploited to detect the frozen salt in a non-invasive way. Simulations and experimental results regarding the detectability of such plugs with different masses/lengths are presented. (author)

  2. GAMMA-RAY OBSERVATIONAL PROPERTIES OF TeV-DETECTED BLAZARS

    SciTech Connect

    Sentuerk, G. D.; Errando, M.; Mukherjee, R.; Boettcher, M.

    2013-02-20

    The synergy between the Fermi-LAT and ground-based Cherenkov telescope arrays gives us the opportunity for the first time to characterize the high-energy emission from blazars over 5 decades in energy, from 100 MeV to 10 TeV. In this study, we perform a Fermi-LAT spectral analysis for TeV-detected blazars and combine it with archival TeV data. We examine the observational properties in the {gamma}-ray band of our sample of TeV-detected blazars and compare the results with X-ray and GeV-selected populations. The spectral energy distributions (SEDs) that result from combining Fermi-LAT and ground-based spectra are studied in detail. Simple parameterizations such as a power-law function do not always reproduce the high-energy SEDs, where spectral features that could indicate intrinsic absorption are observed.

  3. One year of AGILE Terrestrial Gamma-ray Flashes detection in the enhanced configuration

    NASA Astrophysics Data System (ADS)

    Marisaldi, Martino; Ursi, Alessandro; Argan, Andrea; Tavani, Marco; Labanti, Claudio; Fuschino, Fabio; Campana, Riccardo; Mezentsev, Andrey; Østgaard, Nikolai

    2016-04-01

    At the end of March 2015 the onboard configuration of the AGILE MiniCalorimeter was modified in order to disable the veto signal of the Anti-Coincidence shield. This change was motivated by the need to reduce the dead-time for TGF detection to a minimum. The change resulted in a ten fold improvement in Terrestrial Gamma-ray Flashes (TGFs) detection rate and in a nearly dead-time free TGF sample with events as short as 20 microseconds (M. Marisaldi et al., Geophys. Res. Lett. 42, 2015). Estimates based on the initial period of data acquisition in this enhanced configuration suggested the expected yearly TGF rate to be in the range 800-1000. We present here the updated statistical analysis of the enhanced AGILE TGF sample after one complete year of operations in the enhanced configuration.

  4. A Single Tower Configuration of the Modular Gamma Box Counter System - 13392

    SciTech Connect

    Morris, K.; Nakazawa, D.; Francalangia, J.; Gonzalez, H.

    2013-07-01

    Canberra's Standard Gamma Box Counter System is designed to perform accurate quantitative assays of gamma emitting nuclides for a wide range of large containers including B-25 crates and ISO shipping containers. Using a modular building-block approach, the system offers tremendous flexibility for a variety of measurement situations with wide ranges of sample activities and throughput requirements, as well as the opportunity to modify the configuration for other applications at a later date. The typical configuration consists of two opposing towers each equipped with two high purity germanium detectors, and an automated container trolley. This paper presents a modified configuration, consisting of a single tower placed inside a measurement trailer with three detector assemblies, allowing for additional vertical segmentation as well as a viewing a container outside the trailer through the trailer wall. An automatic liquid nitrogen fill system is supplied for each of the detectors. The use of a forklift to move the container for horizontal segmentation is accommodated by creating an additional operational and calibration set-up in the NDA 2000 software to allow for the operator to rotate the container and assay the opposite side, achieving the same sensitivity as a comparable two-tower system. This Segmented Gamma Box Counter System retains the core technologies and design features of the standard configuration. The detector assemblies are shielded to minimize interference from environmental and plant background, and are collimated to provide segmentation of the container. The assembly positions can also be modified in height and distance from the container. The ISOCS calibration software provides for a flexible approach to providing the calibrations for a variety of measurement geometries. The NDA 2000 software provides seamless operation with the current configuration, handling the data acquisition and analysis. In this paper, an overview of this system is discussed

  5. Gamma large area silicon telescope: Applying SI strip detector technology to the detection of gamma rays in space

    NASA Astrophysics Data System (ADS)

    Atwood, W. B.; Bloom, E. D.; Godfrey, G. L.; Hertz, P. L.; Lin, Ying-Chi; Nolan, P. L.; Snyder, A. E.; Taylor, R. E.; Wood, K. S.; Michelson, P. F.

    1992-12-01

    The recent discoveries and excitement generated by EGRET (Energetic Gamma Ray Experiment Telescope) (presently operating on CGRO (Compton Gamma Ray Observatory)) has prompted an investigation into modern technologies ultimately leading to the next generation space based gamma ray telescope. The goal is to design a detector that would increase the data acquisition rate by almost two orders of magnitude beyond EGRET, while at the same time improving on the angular resolution, the energy measurement of reconstructed gamma rays and the triggering capability of the instrument. The proposed GLAST (Gamma Ray Large Area Silicon Telescope) instrument is based on silicon particle detectors that offer the advantages of no consumables, no gas volume, robust (versus fragile), long lived, and self triggering. The GLAST detector is roughly modeled after EGRET in that a tracking module precedes a calorimeter. The GLAST tracker has planes of cross strip (x, y) 300 micrometer match silicon detectors coupled to a thin radiator to measure the coordinates of converted electron-positron pairs. An angular resolution of 0.1 deg at high energy is possible (the low energy angular resolution 100 MeV would be about 2 deg, limited by multiple scattering). The increased depth of the GLAST calorimeter over EGRET's extends the energy range to about 300 GeV.

  6. Minimum detectable concentration as a function of gamma walkover survey technique.

    PubMed

    King, David A; Altic, Nickolas; Greer, Colt

    2012-02-01

    Gamma walkover surveys are often performed by swinging the radiation detector (e.g., a 2-inch by 2-inch sodium iodide) in a serpentine pattern at a near constant height above the ground surface. The objective is to survey an approximate 1-m swath with 100% coverage producing an equal probability of detecting contamination at any point along the swing. In reality, however, the detector height will vary slightly along the swing path, and in some cases the detector may follow a pendulum-like motion significantly reducing the detector response and increasing the minimum detectable concentration. This paper quantifies relative detector responses for fixed and variable height swing patterns and demonstrates negative impacts on the minimum detectable concentration. Minimum detectable concentrations are calculated for multiple contaminated surface areas (0.1, 1.0, 3, 10, and 30 m2), multiple contaminants (60Co, 137Cs, 241Am, and 226Ra), and two minimum heights (5 and 10 cm). Exposure rate estimates used in minimum detectable concentration calculations are produced using MicroShield™ v.7.02 (Grove Software, Inc., 4925 Boonsboro Road #257, Lynchberg, VA 24503) and MDCs are calculated as outlined in NUREG-1575. Results confirm a pendulum-like detector motion can significantly increase MDCs relative to a low flat trajectory, especially for small areas of elevated activity--up to a 47% difference is observed under worst-modeled conditions. PMID:22249469

  7. Interferon-Gamma Release Assay: An Effective Tool to Detect Early Toxoplasma gondii Infection in Mice

    PubMed Central

    Liu, Hongbin; Sun, Ximeng; Zhao, Xinxin; Liu, Xianyong; Suo, Xun

    2015-01-01

    Early diagnosis of Toxoplasma gondii infection before the formation of tissue cysts is vital for treatment, as drugs available for toxoplasmosis cannot kill bradyzoites contained in the cysts. However, current methods, such as antibody-based ELISA, are ineffective for detection of early infection. Here, we developed an interferon-gamma release assay (IGRA), measuring the IFN-γ released by T lymphocytes stimulated by Toxoplasma antigen peptides in vitro, for the detection of T. gondii infection in mice. Splenocytes isolated from infected mice were stimulated by peptides derived from dense granule proteins GRA4 and GRA6 and rhoptry protein ROP7, and released IFN-γ was measured by ELISA. Results showed that both acute and chronic infection could be detected by IGRA. More importantly, IGRA detected infection as early as the third day post infection; while serum IgM and IgG were detected 9 days and 13 days post infection, respectively. Our findings demonstrated that an IGRA-positive and ELISA-negative sample revealed an early infection, indicating the combination of IGRA and ELISA can be employed for the early diagnosis of T. gondii infection in human beings, cats and livestock. PMID:26378802

  8. A Portable Infrasonic Detection System

    NASA Technical Reports Server (NTRS)

    Shams, Qamar A.; Burkett, Cecil G.; Zuckerwar, Allan J.; Lawrenson, Christopher C.; Masterman, Michael

    2008-01-01

    During last couple of years, NASA Langley has designed and developed a portable infrasonic detection system which can be used to make useful infrasound measurements at a location where it was not possible previously. The system comprises an electret condenser microphone, having a 3-inch membrane diameter, and a small, compact windscreen. Electret-based technology offers the lowest possible background noise, because Johnson noise generated in the supporting electronics (preamplifier) is minimized. The microphone features a high membrane compliance with a large backchamber volume, a prepolarized backplane and a high impedance preamplifier located inside the backchamber. The windscreen, based on the high transmission coefficient of infrasound through matter, is made of a material having a low acoustic impedance and sufficiently thick wall to insure structural stability. Close-cell polyurethane foam has been found to serve the purpose well. In the proposed test, test parameters will be sensitivity, background noise, signal fidelity (harmonic distortion), and temporal stability. The design and results of the compact system, based upon laboratory and field experiments, will be presented.

  9. Data and software tools for gamma radiation spectral threat detection and nuclide identification algorithm development and evaluation

    NASA Astrophysics Data System (ADS)

    Portnoy, David; Fisher, Brian; Phifer, Daniel

    2015-06-01

    The detection of radiological and nuclear threats is extremely important to national security. The federal government is spending significant resources developing new detection systems and attempting to increase the performance of existing ones. The detection of illicit radionuclides that may pose a radiological or nuclear threat is a challenging problem complicated by benign radiation sources (e.g., cat litter and medical treatments), shielding, and large variations in background radiation. Although there is a growing acceptance within the community that concentrating efforts on algorithm development (independent of the specifics of fully assembled systems) has the potential for significant overall system performance gains, there are two major hindrances to advancements in gamma spectral analysis algorithms under the current paradigm: access to data and common performance metrics along with baseline performance measures. Because many of the signatures collected during performance measurement campaigns are classified, dissemination to algorithm developers is extremely limited. This leaves developers no choice but to collect their own data if they are lucky enough to have access to material and sensors. This is often combined with their own definition of metrics for measuring performance. These two conditions make it all but impossible for developers and external reviewers to make meaningful comparisons between algorithms. Without meaningful comparisons, performance advancements become very hard to achieve and (more importantly) recognize. The objective of this work is to overcome these obstacles by developing and freely distributing real and synthetically generated gamma-spectra data sets as well as software tools for performance evaluation with associated performance baselines to national labs, academic institutions, government agencies, and industry. At present, datasets for two tracks, or application domains, have been developed: one that includes temporal

  10. Photoelectric detection system. [manufacturing automation

    NASA Technical Reports Server (NTRS)

    Currie, J. R.; Schansman, R. R. (Inventor)

    1982-01-01

    A photoelectric beam system for the detection of the arrival of an object at a discrete station wherein artificial light, natural light, or no light may be present is described. A signal generator turns on and off a signal light at a selected frequency. When the object in question arrives on station, ambient light is blocked by the object, and the light from the signal light is reflected onto a photoelectric sensor which has a delayed electrical output but is of the frequency of the signal light. Outputs from both the signal source and the photoelectric sensor are fed to inputs of an exclusively OR detector which provides as an output the difference between them. The difference signal is a small width pulse occurring at the frequency of the signal source. By filter means, this signal is distinguished from those responsive to sunlight, darkness, or 120 Hz artificial light. In this fashion, the presence of an object is positively established.

  11. Planetary system detection by POINTS

    NASA Technical Reports Server (NTRS)

    Reasenberg, Robert D.

    1993-01-01

    The final report and semiannual reports 1, 2, and 3 in response to the study of 'Planetary System Detection by POINTS' is presented. The grant covered the period from 15 Jun. 1988 through 31 Dec. 1989. The work during that period comprised the further development and refinement of the POINTS concept. The status of the POINTS development at the end of the Grant period was described by Reasenberg in a paper given at the JPL Workshop on Space Interferometry, 12-13 Mar. 1990, and distributed as CfA Preprint 3138. That paper, 'POINTS: a Small Astrometric Interferometer,' follows as Appendix-A. Our proposal P2276-7-09, dated July 1990, included a more detailed description of the state of the development of POINTS at the end of the tenure of Grant NAGW-1355. That proposal, which resulted in Grant NAGW-2497, is included by reference.

  12. Recent developments in the VACIS gamma radiography systems

    NASA Astrophysics Data System (ADS)

    Verbinski, Victor V.; Payne, Jay; Snell, Michael

    1998-12-01

    The VACIS-I prototype system, which has been used at U.S.- Mexico POEs for cargo truck and railroad freight-car inspections, has served as a seedbed for other vehicle inspection systems that are cost-effective, transportable, high- speed, reliable, and utilize very low level radiation exposure. The STAR (stolen automobile recovery) system has been developed and successfully tested at Miami, Florida. Its status and further developmental possibilities are discussed. VACIS-II, the high-resolution (0.5 inches versus 2 inches for VACIS-I) system that scans the entire cargo truck, including the van, is capable of conducting normal as well as oblique scans in 1 1/2 minutes. Railroad VACIS, dubbed SENTINEL, which will scan railroad cars entering the U.S. at about 5 mph is now under development. It has the option of utilizing a Co-60 source for inspecting heavier cargoes. In addition, MOBILE VACIS is in the planning stage. As presently envisioned, it will be mounted on a small vehicle with an extendable detector tower and deployable gamma-ray source to scan a suspect vehicle, either a passenger car or cargo truck, for contraband. The state of development of these systems, as well as some of the options and concerns, are presented.

  13. Cadmium zinc telluride (CZT) nanowire sensors for detection of low energy gamma-ray detection

    NASA Astrophysics Data System (ADS)

    Gandhi, T.; Raja, K. S.; Misra, M.

    2008-04-01

    Bulk single crystals of CdZnTe compound semiconductor is used for room temperature radiation detection in commercial radiation sensors. A large volume of detector material with low defect density is required for increasing the detection efficiency. Manufacture of such a bulky detector-quality material with low defect density is expensive. In this communication, synthesis of nanowires arrays of CdZnTe that can be used for detecting low energy radiation is reported for the first time. CdZnTe ternary compound semiconductor, referred as CZT, was electrodeposited in the form of nanowires onto a TiO II nanotubular template in non-aqueous electrolytes using a pulse-reverse process at 130 °C. Very high electrical resistivity of the CZT nanowires (in the order of 10 10 Ω-cm) was obtained. Such a high resistivity was attributed to the presence of deep defect states such as cadmium vacancies created by the anodic cycle of the pulse-reverse electrodeposition process. Stacks of series connected CZT nanowire arrays were impressed with different bias potentials. The leakage current was in the order of tens of PicoAmperes. When exposed to a radiation source (Am -241, 60 keV), the current flow in the circuit increased. The preliminary results indicate that the CZT nanowire arrays can be used as radiation detector materials at room temperature with a much low bias potential (0.7 - 2.3 V) as against 300 - 500 V applied to the bulk detector materials.

  14. Aerial Radiation Detection

    SciTech Connect

    W. M. Quam

    1999-09-30

    An airborne system designed for the detection of radioactive sources on the soil surface from an aircraft normally senses gamma rays emitted by the source. Gamma rays have the longest path length (least attenuation) through the air of any of the common radioactive emissions and will thus permit source detection at large distances. A secondary benefit from gamma rays detection if that nearly all radioactive isotopes can be identified by the spectrum of gammas emitted. Major gaseous emissions from fuel processing plants emit gammas that may be detected and identified. Some types of special nuclear material also emit neutrons which are also useful for detection at a distance.

  15. Geometric Algorithms for Modeling, Motion, and Animation (GAMMA): Collision Detection Videos from the University of North Carolina GAMMA Research Group

    DOE Data Explorer

    Collision detection has been a fundamental problem in computer animation, physically-based modeling, geometric modeling, and robotics. In these applications, interactions between moving objects are modeled by dynamic constraints and contact analysis. The objects' motions are constrained by various interactions, including collisions. A virtual environment, like a walkthrough, creates a computer-generated world, filled with virtual objects. Such an environment should give the user a feeling of presence, which includes making the images of both the user and the surrounding objects feel solid. For example, the objects should not pass through each other, and things should move as expected when pushed, pulled or grasped. Such actions require accurate collision detection, if they are to achieve any degree of realism. However, there may be hundreds, even thousands of objects in the virtual world, so a naive algorithm could take a long time just to check for possible collisions as the user moves. This is not acceptable for virtual environments, where the issues of interactivity impose fundamental constraints on the system. A fast and interactive collision detection algorithm is a fundamental component of a complex virtual environment. Physically based modeling simulations depend highly on the physical interaction between objects in a scene. Complex physics engines require fast, accurate, and robust proximity queries to maintain a realistic simulation at interactive rates. We couple our proximity query research with physically based modeling to ensure that our packages provide the capabilities of today's physics engines.[Copied from http://www.cs.unc.edu/~geom/collide/index.shtml

  16. Experimental response function of NaI(Tl) scintillation detector for gamma photons and tomographic measurements for defect detection

    NASA Astrophysics Data System (ADS)

    Sharma, Amandeep; Singh, Karamjit; Singh, Bhajan; Sandhu, B. S.

    2011-02-01

    The response function of gamma detector is an important factor for spectrum analysis because some photons and secondary electrons may escape the detector volume before fully depositing their energy, of course destroys the ideal delta function response. An inverse matrix approach, for unfolding of observed pulse-height distribution to a true photon spectrum, is used for construction of experimental response function by formulating a 40 × 40 matrix with bin mesh ( E1/2) of 0.025 (MeV) 1/2 for the present measurements. A tomographic scanner system, operating in a non-destructive and non-invasive way, is also presented for inspection of density variation in any object. The incoherent scattered intensity of 662 keV gamma photons, obtained by unfolding (deconvolution) the experimental pulse-height distribution of NaI(Tl) scintillation detector, provides the desired information. The method is quite sensitive, for showing inclusion of medium Z (atomic number) material (iron) in low Z material (aluminium) and detecting a void of ˜2 mm in size for iron block, to investigate the inhomogeneities in the object. Also, the grey scale images (using "MATLAB") are shown to visualise the presence of defects/inclusion in metal samples.

  17. Neutron Interrogation System For Underwater Threat Detection And Identification

    SciTech Connect

    Barzilov, Alexander P.; Novikov, Ivan S.; Womble, Phil C.

    2009-03-10

    Wartime and terrorist activities, training and munitions testing, dumping and accidents have generated significant munitions contamination in the coastal and inland waters in the United States and abroad. Although current methods provide information about the existence of the anomaly (for instance, metal objects) in the sea bottom, they fail to identify the nature of the found objects. Field experience indicates that often in excess of 90% of objects excavated during the course of munitions clean up are found to be non-hazardous items (false alarm). The technology to detect and identify waterborne or underwater threats is also vital for protection of critical infrastructures (ports, dams, locks, refineries, and LNG/LPG). We are proposing a compact neutron interrogation system, which will be used to confirm possible threats by determining the chemical composition of the suspicious underwater object. The system consists of an electronic d-T 14-MeV neutron generator, a gamma detector to detect the gamma signal from the irradiated object and a data acquisition system. The detected signal then is analyzed to quantify the chemical elements of interest and to identify explosives or chemical warfare agents.

  18. Neutron Interrogation System For Underwater Threat Detection And Identification

    NASA Astrophysics Data System (ADS)

    Barzilov, Alexander P.; Novikov, Ivan S.; Womble, Phil C.

    2009-03-01

    Wartime and terrorist activities, training and munitions testing, dumping and accidents have generated significant munitions contamination in the coastal and inland waters in the United States and abroad. Although current methods provide information about the existence of the anomaly (for instance, metal objects) in the sea bottom, they fail to identify the nature of the found objects. Field experience indicates that often in excess of 90% of objects excavated during the course of munitions clean up are found to be non-hazardous items (false alarm). The technology to detect and identify waterborne or underwater threats is also vital for protection of critical infrastructures (ports, dams, locks, refineries, and LNG/LPG). We are proposing a compact neutron interrogation system, which will be used to confirm possible threats by determining the chemical composition of the suspicious underwater object. The system consists of an electronic d-T 14-MeV neutron generator, a gamma detector to detect the gamma signal from the irradiated object and a data acquisition system. The detected signal then is analyzed to quantify the chemical elements of interest and to identify explosives or chemical warfare agents.

  19. Analysis of VLF signals associated to AGILE Terrestrial Gamma-ray Flashes detected over Central America

    NASA Astrophysics Data System (ADS)

    Marisaldi, Martino; Lyu, Fanchao; Cummer, Steven; Ursi, Alessandro

    2016-04-01

    Analysis of radio signals detected on ground and associated to Terrestrial Gamma-ray Flashes (TGFs) have proven to be a successful tool to extract information on the TGF itself and the possible associated lightning process. Triangulation of Very Low Frequency (VLF) signals by means of the Time Of Arrival technique provides TGF location with few km accuracy. The AGILE satellite is routinely observing TGFs on a narrow band across the Equator, limited by the small satellite orbital inclination (2.5°). However, until recently it was not possible to provide firm associations between AGILE TGFs and radio signals, because of two main limiting factors. First, dead-time effects led to a bias towards long duration events in AGILE TGF sample, which are less likely associated to strong radio pulses. In addition, most VLF detection networks are less sensitive along the equatorial region. Since the end of March 2015 a major change in the AGILE MiniCalorimeter instrument configuration resulted in a ten fold increase in TGF detection rate, and in the detection of events as short as 20 microseconds. 14% of the events in the new sample resulted simultaneous (within 200 microseconds) to sferics detected by the World Wide Lightning Location Network (WWLLN), therefore a source localisation is available for these events. We present here the first analysis of VLF waveforms associated to AGILE TGFs observed above Central America, detected by magnetic field sensors deployed in Puerto Rico. Among the seven TGFs with a WWLLN location at a distance lower than 10000 km from the sensors, four of them have detectable signals. These events are the closest to the sensors, with distance less than 7500 km. We present here the properties of these TGFs and the characteristics of the associated radio waveforms.

  20. Detection of embedded radiation sources using temporal variation of gamma spectral data.

    SciTech Connect

    Shokair, Isaac R.

    2011-09-01

    Conventional full spectrum gamma spectroscopic analysis has the objective of quantitative identification of all the isotopes present in a measurement. For low energy resolution detectors, when photopeaks alone are not sufficient for complete isotopic identification, such analysis requires template spectra for all the isotopes present in the measurement. When many isotopes are present it is difficult to make the correct identification and this process often requires many trial solutions by highly skilled spectroscopists. This report investigates the potential of a new analysis method which uses spatial/temporal information from multiple low energy resolution measurements to test the hypothesis of the presence of a target spectrum of interest in these measurements without the need to identify all the other isotopes present. This method is referred to as targeted principal component analysis (TPCA). For radiation portal monitor applications, multiple measurements of gamma spectra are taken at equally spaced time increments as a vehicle passes through the portal and the TPCA method is directly applicable to this type of measurement. In this report we describe the method and investigate its application to the problem of detection of a radioactive localized source that is embedded in a distributed source in the presence of an ambient background. Examples using simulated spectral measurements indicate that this method works very well and has the potential for automated analysis for RPM applications. This method is also expected to work well for isotopic detection in the presence of spectrally and spatially varying backgrounds as a result of vehicle-induced background suppression. Further work is needed to include effects of shielding, to understand detection limits, setting of thresholds, and to estimate false positive probability.

  1. Detection prospects for GeV neutrinos from collisionally heated gamma-ray bursts with IceCube/DeepCore.

    PubMed

    Bartos, I; Beloborodov, A M; Hurley, K; Márka, S

    2013-06-14

    Jet reheating via nuclear collisions has recently been proposed as the main mechanism for gamma-ray burst (GRB) emission. In addition to producing the observed gamma rays, collisional heating must generate 10-100 GeV neutrinos, implying a close relation between the neutrino and gamma-ray luminosities. We exploit this theoretical relation to make predictions for possible GRB detections by IceCube + DeepCore. To estimate the expected neutrino signal, we use the largest sample of bursts observed by the Burst and Transient Source Experiment in 1991-2000. GRB neutrinos could have been detected if IceCube + DeepCore operated at that time. Detection of 10-100 GeV neutrinos would have significant implications, shedding light on the composition of GRB jets and their Lorentz factors. This could be an important target in designing future upgrades of the IceCube + DeepCore observatory. PMID:25165903

  2. Early detection of Toxoplasma gondii-infected cats by interferon-gamma release assay.

    PubMed

    Yin, Qing; El-Ashram, Saeed; Liu, Xian-Yong; Suo, Xun

    2015-10-01

    Felines, the only definitive hosts that shed the environmentally-durable oocysts, are the key in the transmission of Toxoplasma gondii to all warm-blooded animals. They seroconvert as late as the third week and begin to shed oocysts as early as 3-8 days after being fed tissue cysts. Early detection of Toxoplasma-infected cats is crucial to evaluate Toxoplasma-contaminated environment and potential risks to public health. Moreover, it is fundamental for Toxoplasma infection control. Interferon-gamma release assay (IGRA) is a blood-based test assessing the presence of IFN-γ released by the T-lymphocytes directed against specific antigens, which is an ideal assay for early detection of Toxoplasma-infected cats. Here, cats were orally infected with the tissue cysts and blood was collected for toxoplasmic antigen stimulation, and the released IFN-γ was measured by ELISA. Results showed that Toxoplasma-infection was detected by IGRA as early as 4 days post-infection (dpi); while serum Toxoplasma IgM and IgG were detected by ELISA at 10 dpi and 14 dpi, respectively. Our findings demonstrated that IGRA-positive and ELISA-negative samples revealed an early Toxoplasma infection in cats, indicating a new strategy for the early diagnosis of Toxoplasma infection by combining IGRA and ELISA. Therefore, IGRA could emerge as a reliable diagnostic tool for the exploration of cat toxoplasmosis prevalence and its potential risks to public health. PMID:26297953

  3. Double Chooz Neutron Detection Efficiency with Calibration System

    NASA Astrophysics Data System (ADS)

    Chang, Pi-Jung

    2012-03-01

    The Double Chooz experiment is designed to search for a non-vanishing mixing angle theta13 with unprecedented sensitivity. The first results obtained with the far detector only indicate a non-zero value of theta13. The Double Chooz detector system consists of a main detector, an outer veto system and a number of calibration systems. The main detector consists of a series of concentric cylinders. The target vessel, a liquid scintillator loaded with 0.1% Gd, is surrounded by the gamma-catcher, a non-loaded liquid scintillator. A buffer region of non-scintillating liquid surrounds the gamma-catcher and serves to decrease the level of accidental background. There is the Inner Veto region outside the buffer. The experiment is calibrated with light sources, radioactive point sources, cosmics and natural radioactivity. The radio-isotopes sealed in miniature capsules are deployed in the target and the gamma-catcher. Neutron detection efficiency is one of the major systematic components in the measurement of anti-neutrino disappearance. An untagged 252Cf source was used to determine fractions of neutron captures on Gd, neutron capture time systematic and neutron delayed energy systematic. The details will be explained in the talk.

  4. Compton scattering in terrestrial gamma-ray flashes detected with the Fermi gamma-ray burst monitor

    NASA Astrophysics Data System (ADS)

    Fitzpatrick, Gerard; Cramer, Eric; McBreen, Sheila; Briggs, Michael S.; Foley, Suzanne; Tierney, David; Chaplin, Vandiver L.; Connaughton, Valerie; Stanbro, Matthew; Xiong, Shaolin; Dwyer, Joseph; Fishman, Gerald J.; Roberts, Oliver J.; von Kienlin, Andreas

    2014-08-01

    Terrestrial gamma-ray flashes (TGFs) are short intense flashes of gamma rays associated with lightning activity in thunderstorms. Using Monte Carlo simulations of the relativistic runaway electron avalanche (RREA) process, theoretical predictions for the temporal and spectral evolution of TGFs are compared to observations made with the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-ray Space Telescope. Assuming a single source altitude of 15 km, a comparison of simulations to data is performed for a range of empirically chosen source electron variation time scales. The data exhibit a clear softening with increased source distance, in qualitative agreement with theoretical predictions. The simulated spectra follow this trend in the data, but tend to underestimate the observed hardness. Such a discrepancy may imply that the basic RREA model is not sufficient. Alternatively, a TGF beam that is tilted with respect to the zenith could produce an evolution with source distance that is compatible with the data. Based on these results, we propose that the source electron distributions of TGFs observed by GBM vary on time scales of at least tens of microseconds, with an upper limit of ˜100 μs.

  5. Pulse properties of terrestrial gamma-ray flashes detected by the Fermi Gamma-Ray Burst Monitor

    NASA Astrophysics Data System (ADS)

    Foley, S.; Fitzpatrick, G.; Briggs, M. S.; Connaughton, V.; Tierney, D.; McBreen, S.; Dwyer, J. R.; Chaplin, V. L.; Bhat, P. N.; Byrne, D.; Cramer, E.; Fishman, G. J.; Xiong, S.; Greiner, J.; Kippen, R. M.; Meegan, C. A.; Paciesas, W. S.; Preece, R. D.; Kienlin, A.; Wilson-Hodge, C.

    2014-07-01

    The Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-ray Space Telescope has triggered on over 300 terrestrial gamma-ray flashes (TGFs) since its launch in June 2008. With 14 detectors, GBM collects on average ˜100 counts per triggered TGF, enabling unprecedented studies of the time profiles of TGFs. Here we present the first rigorous analysis of the temporal properties of a large sample of TGFs (278), including the distributions of the rise and fall times of the individual pulses and their durations. A variety of time profiles are observed with 19% of TGFs having multiple pulses separated in time and 31 clear cases of partially overlapping pulses. The effect of instrumental dead time and pulse pileup on the temporal properties are also presented. As the observed gamma ray pulse structure is representative of the electron flux at the source, TGF pulse parameters are critical to distinguish between relativistic feedback discharge and lightning leader models. We show that at least 67% of TGFs at satellite altitudes are significantly asymmetric. For the asymmetric pulses, the rise times are almost always shorter than the fall times. Those which are not are consistent with statistical fluctuations. The median rise time for asymmetric pulses is ˜3 times shorter than for symmetric pulses while their fall times are comparable. The asymmetric shapes observed are consistent with the relativistic feedback discharge model when Compton scattering of photons between the source and Fermi is included, and instrumental effects are taken into account.

  6. Instructions for calibrating gamma detectors using the Canberra-Nuclear Data Genie Gamma Spectroscopy System

    SciTech Connect

    Brunk, J.L.

    1995-09-01

    A straight forward protocol provides a way to guide the calibration of a gamma detector for a particular geometry and material. Several programs have used the Low Level Gamma Counting Facility of the Health and Ecological Assessment Division of the Lawrence Livermore National Laboratory to count a variety of large environmental samples contained in several unique geometries. The equipment and calibration requirements needed to analyze these types of samples are explained. This document describes the calibration protocol that has been developed and describes how it is used to calibrate the detectors.

  7. A pulse shape discriminator and an online system for the balloon-borne hard X-ray/gamma-ray detector

    NASA Astrophysics Data System (ADS)

    Takahashi, T.; Kamae, T.; Tanaka, M.; Gunji, S.; Miyazuki, S.; Tamura, T.; Sekimoto, Y.; Yamaoka, N.; Nishimura, J.; Yajima, N.

    Attention is given to a new kind of phoswich counters (the well-type phoswich counter) that will be capable of detecting very low flux hard X-rays/gamma-rays (40-1000 keV) from astronomical objects. A specially designed pulse-shape discriminator (PSD) selects hard X-rays/gamma-rays that has deposited energy only in the detection part. Sixty-four such counters are assembled into an array where each phoswich element acts as an active shield to the neighboring elements too. The ADCs, the TDCs, the hit-pattern latches, and the precision clock are read out by a VME-based online system, stored on an 8-mm video tape, and transmitted to the ground station. The design and performance of the pulse shape discriminator and the online system are described.

  8. New correction method for dynamic error in on-line gamma ray thickness detection.

    PubMed

    Liang, Manchun; Yi, Hongchang; Lin, Qian

    2009-11-01

    In this paper, we present a new method to correct dynamic error (DE) in on-line gamma ray thickness measurement, which significantly improves measurement precision over traditional method, in most cases, by one order of magnitude. Theoretical analysis of DE is presented and the correction method is proposed. In order to further prove our theory, Monte Carlo simulation is taken and the performance improvement is given. The method has been successfully applied to our thickness measurement system and brought dramatic improvement to its dynamic precision. PMID:19682915

  9. Method for detecting water equivalent of snow using secondary cosmic gamma radiation

    DOEpatents

    Condreva, K.J.

    1997-01-14

    Water equivalent of accumulated snow determination by measurement of secondary background cosmic radiation attenuation by the snowpack. By measuring the attenuation of 3-10 MeV secondary gamma radiation it is possible to determine the water equivalent of snowpack. The apparatus is designed to operate remotely to determine the water equivalent of snow in areas which are difficult or hazardous to access during winter, accumulate the data as a function of time and transmit, by means of an associated telemetry system, the accumulated data back to a central data collection point for analysis. The electronic circuitry is designed so that a battery pack can be used to supply power. 4 figs.

  10. Method for detecting water equivalent of snow using secondary cosmic gamma radiation

    DOEpatents

    Condreva, Kenneth J.

    1997-01-01

    Water equivalent of accumulated snow determination by measurement of secondary background cosmic radiation attenuation by the snowpack. By measuring the attentuation of 3-10 MeV secondary gamma radiation it is possible to determine the water equivalent of snowpack. The apparatus is designed to operate remotely to determine the water equivalent of snow in areas which are difficult or hazardous to access during winter, accumulate the data as a function of time and transmit, by means of an associated telemetry system, the accumulated data back to a central data collection point for analysis. The electronic circuitry is designed so that a battery pack can be used to supply power.

  11. Mobile neutron/gamma waste assay system for characterization of waste containing transuranics, uranium, and fission/activation products

    SciTech Connect

    Davidson, D.R.; Haggard, D.; Lemons, C.

    1994-12-31

    A new integrated neutron/gamma assay system has been built for measuring 55-gallon drums at Pacific Northwest Laboratory. The system is unique because it allows simultaneous measurement of neutrons and gamma-rays. This technique also allows measurement of transuranics (TRU), uranium, and fission/activation products, screening for shielded Special Nuclear Material prior to disposal, and critically determinations prior to transportation. The new system is positioned on a platform with rollers and installed inside a trailer or large van to allow transportation of the system to the waste site instead of movement of the drums to the scanner. The ability to move the system to the waste drums is particularly useful for drum retrieval programs common to all DOE sites and minimizes transportation problems on the site. For longer campaigns, the system can be moved into a facility. The mobile system consists of two separate subsystems: a passive Segmented Gamma Scanner (SGS) and a {open_quotes}clam-shell{close_quotes} passive neutron counter. The SGS with high purity germanium detector and {sup 75}Se transmission source simultaneously scan the height of the drum allowing identification of unshieled {open_quotes}hot spots{close_quotes} in the drum or segments where the matrix is too dense for the transmission source to penetrate. Dense segments can flag shielding material that could be used to hide plutonium or uranium during the gamma analysis. The passive nuetron counter with JSR-12N Neutron Coincidence Analyzer measures the coincident neutrons from the spontaneous fission of even isotopes of plutonium. Because high-density shielding produces minimal absorption of neutrons, compared to gamma rays, the passive neutron portion of the system can detect shielded SNM. Measurements to evaluate the performance of the system are still underway at Pacific Northwest Laboratory.

  12. GAMMA-RAY SIGNAL FROM THE PULSAR WIND IN THE BINARY PULSAR SYSTEM PSR B1259-63/LS 2883

    SciTech Connect

    Khangulyan, Dmitry; Bogovalov, Sergey V.; Ribo, Marc E-mail: felix.aharonian@dias.ie E-mail: mribo@am.ub.es

    2011-12-01

    Binary pulsar systems emit potentially detectable components of gamma-ray emission due to Comptonization of the optical radiation of the companion star by relativistic electrons of the pulsar wind, both before and after termination of the wind. The recent optical observations of binary pulsar system PSR B1259-63/LS 2883 revealed radiation properties of the companion star which differ significantly from previous measurements. In this paper, we study the implications of these observations for the interaction rate of the unshocked pulsar wind with the stellar photons and the related consequences for fluxes of high energy and very high energy (VHE) gamma rays. We show that the signal should be strong enough to be detected with Fermi close to the periastron passage, unless the pulsar wind is strongly anisotropic or the Lorentz factor of the wind is smaller than 10{sup 3} or larger than 10{sup 5}. The higher luminosity of the optical star also has two important implications: (1) attenuation of gamma rays due to photon-photon pair production and (2) Compton drag of the unshocked wind. While the first effect has an impact on the light curve of VHE gamma rays, the second effect may significantly decrease the energy available for particle acceleration after termination of the wind.

  13. Is the Stellar System WR 11 a Gamma-Ray Source?

    NASA Astrophysics Data System (ADS)

    Benaglia, Paula

    2016-04-01

    Many early-type stars are in systems; some of them have been indicated as putative high-energy emitters. The radiation would be produced at the region where two stellar winds collide. Compelling evidence of such emission was found only for the colliding-wind binary (CWB) Eta Car, which was associated to a GeV source. Very recently, the closest CWB, WR 11, was proposed as a counterpart of a 6σ emission excess, measured with the Fermi LAT satellite. We sought evidence to support or reject the hypothesis that WR 11 is responsible of the gamma-ray excess. Archive radio interferometric data at 1.4 and 2.5 GHz taken with the Australia Telescope Compact Array along 16 dates were reduced. The sizes of the field-of-view at 2.5 GHz and of the central region of the Fermi LAT excess are alike. We analysed the emission of the WR 11 field, characterised the radio sources detected and derived their spectral indices, to investigate their nature. Eight sources with fluxes above 10 mJy were detected at both frequencies. All but one (WR 11) showed negative spectral indices. Four of them were identified with known objects, including WR 11. A fifth source, labeled here S6, is a promising candidate to produce gamma-ray emission, besides the CWB WR 11.

  14. Unveiling the Gamma-Ray Source Count Distribution Below the Fermi Detection Limit with Photon Statistics

    NASA Astrophysics Data System (ADS)

    Zechlin, Hannes-S.; Cuoco, Alessandro; Donato, Fiorenza; Fornengo, Nicolao; Vittino, Andrea

    2016-08-01

    The source-count distribution as a function of their flux, {dN}/{dS}, is one of the main quantities characterizing gamma-ray source populations. We employ statistical properties of the Fermi Large Area Telescope (LAT) photon counts map to measure the composition of the extragalactic gamma-ray sky at high latitudes (| b| ≥slant 30°) between 1 and 10 GeV. We present a new method, generalizing the use of standard pixel-count statistics, to decompose the total observed gamma-ray emission into (a) point-source contributions, (b) the Galactic foreground contribution, and (c) a truly diffuse isotropic background contribution. Using the 6 yr Fermi-LAT data set (P7REP), we show that the {dN}/{dS} distribution in the regime of so far undetected point sources can be consistently described with a power law with an index between 1.9 and 2.0. We measure {dN}/{dS} down to an integral flux of ∼ 2× {10}-11 {{cm}}-2 {{{s}}}-1, improving beyond the 3FGL catalog detection limit by about one order of magnitude. The overall {dN}/{dS} distribution is consistent with a broken power law, with a break at {2.1}-1.3+1.0× {10}-8 {{cm}}-2 {{{s}}}-1. The power-law index {n}1={3.1}-0.5+0.7 for bright sources above the break hardens to {n}2=1.97+/- 0.03 for fainter sources below the break. A possible second break of the {dN}/{dS} distribution is constrained to be at fluxes below 6.4× {10}-11 {{cm}}-2 {{{s}}}-1 at 95% confidence level. The high-latitude gamma-ray sky between 1 and 10 GeV is shown to be composed of ∼25% point sources, ∼69.3% diffuse Galactic foreground emission, and ∼6% isotropic diffuse background.

  15. Detecting gamma-ray bursts with the pierre auger observatory using the single particle technique

    SciTech Connect

    Allard, Denis; Parizot, E.; Bertou, Xavier; Beatty, J.; Vernois, M.Du; Nitz, D.; Rodriguez, G.

    2005-08-01

    During the past ten years, gamma-ray Bursts (GRB) have been extensively studied in the keV-MeV energy range but the higher energy emission still remains mysterious. Ground based observatories have the possibility to investigate energy range around one GeV using the ''single particle technique''. The aim of the present study is to investigate the capability of the Pierre Auger Observatory to detect the high energy emission of GRBs with such a technique. According to the detector response to photon showers around one GeV, and making reasonable assumptions about the high energy emission of GRBs, we show that the Pierre Auger Observatory is a competitive instrument for this technique, and that water tanks are very promising detectors for the single particle technique.

  16. Recent results in a search for inorganic scintillators for x- and gamma-ray detection

    SciTech Connect

    Moses, W.W.; Weber, M.J.; Derenzo, S.E.; Perry, D.; Berahl, P.

    1997-10-01

    We present recent results from an ongoing search for inorganic scintillators for gamma ray detection in which we measure the scintillation properties (luminous efficiency, decay time, and emission wavelength) of powdered samples excited by brief x-ray pulses. Recent promising candidates include cerium doped lutetium borate (LuBO{sub 3}) and the lutetium double phosphates K{sub 3}Lu(PO{sub 4}){sub 2} and Rb{sub 3}Lu(PO{sub 4}){sub 2}, which have luminous intensities above 25,000 photons/MeV. In order to find scintillators that are compatible with silicon photodetectors, we have tested over 1,100 samples using a photomultiplier tube with a GaAs:Cs photocathode, which is sensitive to emissions from 200-950 nm. While many samples exhibited strong emissions in the 600-900 nm range, all had decay times that were larger than 10 {mu}s.

  17. Multiwavelength Observations of the Gamma-ray Blazars Detected by AGILE

    NASA Astrophysics Data System (ADS)

    D'Ammando, F.; Vercellone, S.; Donnarumma, I.; Pacciani, L.; Pucella, G.; Tavani, M.; Vittorini, V.; Bulgarelli, A.; Chen, A. W.; Giuliani, A.; Longo, F.; AGILE Team

    2011-02-01

    Since its launch in April 2007, the AGILE satellite detected with the Gamma-Ray Imaging Detector several blazars in high γ-ray activity: 3C 279, 3C 454.3, PKS 1510-089, S5 0716+714, 3C 273, W Comae and Mrk 421. Thanks to the rapid dissemination of our alerts, we were able to obtain multiwavelength ToO data from other observatories such as Spitzer, Swift, RXTE, Suzaku, INTEGRAL, MAGIC, VERITAS, as well as radio-to-optical coverage by means of the GASP Project of the WEBT and the REM Telescope. This large multifrequency coverage gave us the opportunity to study truly simultaneous spectral energy distributions of these sources from radio to γ-ray energy bands and to investigate the different mechanisms responsible for their emission. We present an overview of the AGILE results on these γ-ray blazars and the relative multifrequency data.

  18. Functionalization of Polymers with Fluorescent and Neutron Sensitive Groups for Efficient Neutron and Gamma Detection

    NASA Astrophysics Data System (ADS)

    Mahl, Adam; Yemam, Henok; Remedes, Tyler; Stuntz, Jack; Koldemir, Unsal; Sellinger, Alan; Greife, Uwe

    2015-10-01

    This presentation will review the efforts made by an interdisciplinary development project aimed at cost-effective, thermal neutron sensitive, plastic scintillators as part of the communities efforts towards replacing 3He based detectors. Colorado School of Mines researchers with backgrounds in Physics and Chemistry have worked on the incorporation of 10B in plastics through admixture of various commercial and novel dopants developed at CSM. In addition, new fluorescent dopants have been developed for plastic scintillators in an effort towards better understanding quenching effects and scintillator response to thermal neutrons via pulse shape discrimination methods. Results on transparent samples using fluorescent spectroscopy and gamma/neutron excitation will be presented. Funded via Department of Homeland Security - Domestic Nuclear Detection Office.

  19. Design of dual-road transportable portal monitoring system for visible light and gamma-ray imaging

    NASA Astrophysics Data System (ADS)

    Karnowski, Thomas P.; Cunningham, Mark F.; Goddard, James S.; Cheriyadat, Anil M.; Hornback, Donald E.; Fabris, Lorenzo; Kerekes, Ryan A.; Ziock, Klaus-Peter; Bradley, E. Craig; Chesser, J.; Marchant, W.

    2010-04-01

    The use of radiation sensors as portal monitors is increasing due to heightened concerns over the smuggling of fissile material. Transportable systems that can detect significant quantities of fissile material that might be present in vehicular traffic are of particular interest, especially if they can be rapidly deployed to different locations. To serve this application, we have constructed a rapid-deployment portal monitor that uses visible-light and gamma-ray imaging to allow simultaneous monitoring of multiple lanes of traffic from the side of a roadway. The system operation uses machine vision methods on the visible-light images to detect vehicles as they enter and exit the field of view and to measure their position in each frame. The visible-light and gamma-ray cameras are synchronized which allows the gamma-ray imager to harvest gamma-ray data specific to each vehicle, integrating its radiation signature for the entire time that it is in the field of view. Thus our system creates vehicle-specific radiation signatures and avoids source confusion problems that plague non-imaging approaches to the same problem. Our current prototype instrument was designed for measurement of upto five lanes of freeway traffic with a pair of instruments, one on either side of the roadway. Stereoscopic cameras are used with a third "alignment" camera for motion compensation and are mounted on a 50' deployable mast. In this paper we discuss the design considerations for the machine-vision system, the algorithms used for vehicle detection and position estimates, and the overall architecture of the system. We also discuss system calibration for rapid deployment. We conclude with notes on preliminary performance and deployment.

  20. Design of Dual-Road Transportable Portal Monitoring System for Visible Light and Gamma-Ray Imaging

    SciTech Connect

    Karnowski, Thomas Paul; Cunningham, Mark F; Goddard Jr, James Samuel; Cheriyadat, Anil M; Hornback, Donald Eric; Fabris, Lorenzo; Kerekes, Ryan A; Ziock, Klaus-Peter; Bradley, Eric Craig; Chesser, Joel B; Marchant, William

    2010-01-01

    The use of radiation sensors as portal monitors is increasing due to heightened concerns over the smuggling of fissile material. Transportable systems that can detect significant quantities of fissile material that might be present in vehicular traffic are of particular interest, especially if they can be rapidly deployed to different locations. To serve this application, we have constructed a rapid-deployment portal monitor that uses visible-light and gamma-ray imaging to allow simultaneous monitoring of multiple lanes of traffic from the side of a roadway. The system operation uses machine vision methods on the visible-light images to detect vehicles as they enter and exit the field of view and to measure their position in each frame. The visible-light and gamma-ray cameras are synchronized which allows the gamma-ray imager to harvest gamma-ray data specific to each vehicle, integrating its radiation signature for the entire time that it is in the field of view. Thus our system creates vehicle-specific radiation signatures and avoids source confusion problems that plague non-imaging approaches to the same problem. Our current prototype instrument was designed for measurement of upto five lanes of freeway traffic with a pair of instruments, one on either side of the roadway. Stereoscopic cameras are used with a third alignment camera for motion compensation and are mounted on a 50 deployable mast. In this paper we discuss the design considerations for the machine-vision system, the algorithms used for vehicle detection and position estimates, and the overall architecture of the system. We also discuss system calibration for rapid deployment. We conclude with notes on preliminary performance and deployment.

  1. Detection of Interferon gamma using graphene and aptamer based FET-like electrochemical biosensor.

    PubMed

    Farid, Sidra; Meshik, Xenia; Choi, Min; Mukherjee, Souvik; Lan, Yi; Parikh, Devanshi; Poduri, Shripriya; Baterdene, Undarmaa; Huang, Ching-En; Wang, Yung Yu; Burke, Peter; Dutta, Mitra; Stroscio, Michael A

    2015-09-15

    One of the primary goals in the scientific community is the specific detection of proteins for the medical diagnostics and biomedical applications. Interferon-gamma (IFN-γ) is associated with the tuberculosis susceptibility, which is one of the major health problems globally. We have therefore developed a DNA aptamer-based electrochemical biosensor that is used for the detection of IFN-γ with high selectivity and sensitivity. A graphene monolayer-based FET-like structure is incorporated on a PDMS substrate with the IFN-γ aptamer attached to graphene. Addition of target molecule induces a change in the charge distribution in the electrolyte, resulting in increase in electron transfer efficiency that was actively sensed by monitoring the change in current from the device. Change in current appears to be highly sensitive to the IFN-γ concentrations ranging from nanomolar (nM) to micromolar (μM) range. The detection limit of our IFN-γ electrochemical biosensor is found to be 83 pM. Immobilization of aptamer on graphene surface is verified using unique structural approach by Atomic Force Microscopy. Such simple and sensitive electrochemical biosensor has potential applications in infectious disease monitoring, immunology and cancer research in the future. PMID:25919809

  2. Fermi Detection of Delayed GeV Emission from the Short Gamma-Ray Burst 081024B

    NASA Astrophysics Data System (ADS)

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Asano, K.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman, B. M.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bhat, P. N.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Briggs, M. S.; Brigida, M.; Bruel, P.; Burgess, J. M.; Burnett, T. H.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Carrigan, S.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö.; Chaplin, V.; Charles, E.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Cominsky, L. R.; Connaughton, V.; Conrad, J.; Cutini, S.; Dermer, C. D.; de Angelis, A.; de Palma, F.; Digel, S. W.; Silva, E. do Couto e.; Drell, P. S.; Dubois, R.; Dumora, D.; Farnier, C.; Favuzzi, C.; Fegan, S. J.; Fishman, G.; Focke, W. B.; Fortin, P.; Frailis, M.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giebels, B.; Giglietto, N.; Giommi, P.; Giordano, F.; Glanzman, T.; Godfrey, G.; Granot, J.; Grenier, I. A.; Grondin, M.-H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Haynes, R. H.; Hays, E.; Horan, D.; Hughes, R. E.; Jackson, M. S.; Jóhannesson, G.; Johnson, A. S.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kawai, N.; Kerr, M.; Kippen, R. M.; Knödlseder, J.; Kocevski, D.; Kocian, M. L.; Komin, N.; Kouveliotou, C.; Kuehn, F.; Kuss, M.; Lande, J.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Makeev, A.; Mazziotta, M. N.; McBreen, S.; McEnery, J. E.; McGlynn, S.; Meegan, C.; Mészáros, P.; Meurer, C.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monte, C.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Paciesas, W. S.; Paneque, D.; Panetta, J. H.; Parent, D.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Piron, F.; Porter, T. A.; Preece, R.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Reposeur, T.; Ripken, J.; Ritz, S.; Rochester, L. S.; Rodriguez, A. Y.; Roth, M.; Ryde, F.; Sadrozinski, H. F.-W.; Sanchez, D.; Sander, A.; Saz Parkinson, P. M.; Scargle, J. D.; Schalk, T. L.; Sgrò, C.; Siskind, E. J.; Smith, D. A.; Smith, P. D.; Spandre, G.; Spinelli, P.; Stamatikos, M.; Strickman, M. S.; Suson, D. J.; Tagliaferri, G.; Tajima, H.; Takahashi, H.; Tanaka, T.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Toma, K.; Torres, D. F.; Tosti, G.; Tramacere, A.; Troja, E.; Uchiyama, Y.; Usher, T. L.; van der Horst, A. J.; Vasileiou, V.; Vilchez, N.; Vitale, V.; von Kienlin, A.; Waite, A. P.; Wang, P.; Wilson-Hodge, C.; Winer, B. L.; Wood, K. S.; Wu, X. F.; Yamazaki, R.; Ylinen, T.; Ziegler, M.

    2010-03-01

    We report on the detailed analysis of the high-energy extended emission from the short gamma-ray burst (GRB) 081024B detected by the Fermi Gamma-ray Space Telescope. Historically, this represents the first clear detection of temporal extended emission from a short GRB. The light curve observed by the Fermi Gamma-ray Burst Monitor lasts approximately 0.8 s whereas the emission in the Fermi Large Area Telescope lasts for about 3 s. Evidence of longer lasting high-energy emission associated with long bursts has been already reported by previous experiments. Our observations, together with the earlier reported study of the bright short GRB 090510, indicate similarities in the high-energy emission of short and long GRBs and open the path to new interpretations.

  3. Prospects for High Energy Detection of Microquasars with the AGILE and GLAST Gamma-Ray Telescopes

    SciTech Connect

    Santolamazza, Patrizia; Pittori, Carlotta; Verrecchia, Francesco

    2007-08-21

    We estimate the sensitivities of the AGILE and GLAST {gamma}-ray experiments taking into account two cases for the galactic {gamma}-ray diffuse background (at high galactic latitude and toward the galactic center). Then we use sensitivities to estimate microquasar observability with the two experiments, assuming the {gamma}-ray emission above 100 MeV of a recent microquasar model.

  4. CAXSS: an intelligent threat-detection system

    NASA Astrophysics Data System (ADS)

    Feather, Thomas; Guan, Ling; Lee-Kwen, Adrian; Paranjape, Raman B.

    1993-04-01

    Array Systems Computing Inc. (ASC) is developing a prototype Computer Assisted X-ray Screening System (CAXSS) which uses state-of-the-art image processing and computer vision technology to detect threats seen in x-ray images of passenger carry-on luggage at national and international airports. This system is successful in detecting weapons including guns, knives, grenades, aerosol cans, etc. Currently, bomb detection is also being implemented; preliminary results using this bomb detector are promising.

  5. 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.

  6. Title: MAGIC detects exceptionally high activity from PKS 1510-089 at very high energy gamma-rays

    NASA Astrophysics Data System (ADS)

    Mirzoyan, Razmik

    2016-06-01

    The MAGIC telescopes have detected an increase in the Very High Energy gamma-ray flux from PKS 1510-089 (RA=15 12 50.5, dec=-09 06 00, J2000.0). The preliminary analysis of the MAGIC data taken on 2016/05/30 for 2.7 hours, indicates a highly significant signal (significance > 60 sigma).

  7. Swift Follow-up of the New Gamma-ray Detection of TXS 1731+152A

    NASA Astrophysics Data System (ADS)

    Ojha, R.; Carpenter, B.; Krauss, F.; Becerra, J.

    2014-08-01

    Following the gamma-ray detection of the flat spectrum radio quasar TXS 1731+152A by Fermi/LAT on 2014 August 13 (ATel #6395), two Swift target of opportunity observations were performed on 2014 August 16 and 18.

  8. Experimental study of the vidicon system for information recording using the wide-gap spark chamber of gamma - telescope gamma-I

    NASA Technical Reports Server (NTRS)

    Akimov, V. V.; Bazer-Bashv, R.; Voronov, S. A.; Galper, A. M.; Gro, M.; Kalinkin, L. F.; Kerl, P.; Kozlov, V. D.; Koten, F.; Kretol, D.

    1979-01-01

    The development of the gamma ray telescope is investigated. The wide gap spark chambers, used to identify the gamma quanta and to determine the directions of their arrival, are examined. Two systems of information recording with the spark chambers photographic and vidicon system are compared.

  9. Olfactory system gamma oscillations: the physiological dissection of a cognitive neural system

    PubMed Central

    Rojas-Líbano, Daniel

    2008-01-01

    Oscillatory phenomena have been a focus of dynamical systems research since the time of the classical studies on the pendulum by Galileo. Fast cortical oscillations also have a long and storied history in neurophysiology, and olfactory oscillations have led the way with a depth of explanation not present in the literature of most other cortical systems. From the earliest studies of odor-evoked oscillations by Adrian, many reports have focused on mechanisms and functional associations of these oscillations, in particular for the so-called gamma oscillations. As a result, much information is now available regarding the biophysical mechanisms that underlie the oscillations in the mammalian olfactory system. Recent studies have expanded on these and addressed functionality directly in mammals and in the analogous insect system. Sub-bands within the rodent gamma oscillatory band associated with specific behavioral and cognitive states have also been identified. All this makes oscillatory neuronal networks a unique interdisciplinary platform from which to study neurocognitive and dynamical phenomena in intact, freely behaving animals. We present here a summary of what has been learned about the functional role and mechanisms of gamma oscillations in the olfactory system as a guide for similar studies in other cortical systems. PMID:19003484

  10. A Multi-Layer Phoswich Radioxenon Detection System

    SciTech Connect

    David M. Hamby

    2008-07-14

    Laboratory radioactive sources were used to characterize the phoswich detector. The CaF{sub 2} scintillator has a low light-yield and slow decay time, thus produces very small signals due to low-energy gamma rays or X-rays. Therefore, detection of 30 keV X-rays (from the xenon radioisotopes) using this layer and discriminating its very small signals from electronic noise was a challenging task. Several solutions were considered and experimentally evaluated. We found that the best solution would be extending the fast triangular filter from 10 taps to 30 taps. This will extend the peaking time of this filter from 25 nsec to 75 nsec. The digital filter is implemented in FPGA on our DPP2.0 and is used to trigger the detection system. Functionality of the new filter in capturing and discriminating 30 keV X-rays was confirmed by using a {sup 133}Ba gamma-ray source. Development of the DPP GUI software has continued with the addition of two new panels to display histograms of beta/gamma and beta/x-ray coincidence events. This includes coincidence events from a single channel, as well as two-channel, coincidence event. A pileup rejection algorithm has been implemented in the FPGA code, and controls to adjust its sensitivity have been added to the GUI. Work has begun on a new prototype system to develop a USB host interface between the PC and the FPGA to end reliance on Opal Kelly prototyping boards; the hardware for this system has been completely assembled, and the PC-side software is currently in development.

  11. The Use of the BAT Instrument on SWIFT for the Detection of Prompt Gamma-Ray Emission from Novae

    NASA Technical Reports Server (NTRS)

    Skinner, Gerry; Senziani, Fabio; Jean, Pierre; Hernanz, Margarita

    2007-01-01

    Gamma-rays are expected to be emitted during and immediately following a nova explosion due to the annihilation of positrons emitted by freshly produced short-lived radioactive isotopes. The expected gammaray emission is relatively short-lived and as nova explosions are unpredictable, the best chance of detecting the gamma-rays is with n wide field instrument. At the time when the flux is expected to rcach its peak, most of the gamma-ray production is at depths such that the photons suffer several Compton scatterings before escaping, degrading their energy down to the hard X-ray band (10s of keV). SWIFT/BAT is a very wide field coded mask instrument working in the energy band 14-190 keV and so is very well suited to the search for such gamma-rays. A retrospective search is being made in the BAT data for evidence for gamma-ray emission from the direction of novae at around the time of their explosion. So far the only positive detection is of RS Ophiuchi and in this case the emission is probably due to shock heating.

  12. Application of the EXtrapolated Efficiency Method (EXEM) to infer the gamma-cascade detection efficiency in the actinide region

    NASA Astrophysics Data System (ADS)

    Ducasse, Q.; Jurado, B.; Mathieu, L.; Marini, P.; Morillon, B.; Aiche, M.; Tsekhanovich, I.

    2016-08-01

    The study of transfer-induced gamma-decay probabilities is very useful for understanding the surrogate-reaction method and, more generally, for constraining statistical-model calculations. One of the main difficulties in the measurement of gamma-decay probabilities is the determination of the gamma-cascade detection efficiency. In Boutoux et al. (2013) [10] we developed the EXtrapolated Efficiency Method (EXEM), a new method to measure this quantity. In this work, we have applied, for the first time, the EXEM to infer the gamma-cascade detection efficiency in the actinide region. In particular, we have considered the 238U(d,p)239U and 238U(3He,d)239Np reactions. We have performed Hauser-Feshbach calculations to interpret our results and to verify the hypothesis on which the EXEM is based. The determination of fission and gamma-decay probabilities of 239Np below the neutron separation energy allowed us to validate the EXEM.

  13. DETECTION OF THE {gamma}-RAY BINARY LS I +61 Degree-Sign 303 IN A LOW-FLUX STATE AT VERY HIGH ENERGY {gamma}-RAYS WITH THE MAGIC TELESCOPES IN 2009

    SciTech Connect

    Aleksic, J.; Blanch, O.; Alvarez, E. A.; Asensio, M.; Barrio, J. A.; Antonelli, L. A.; Bonnoli, G.; Antoranz, P.; Backes, M.; Bastieri, D.; Becerra Gonzalez, J.; Berger, K.; Bednarek, W.; Berdyugin, A.; Bernardini, E.; Biland, A.; Boller, A.; Bock, R. K.; Borla Tridon, D.; Bosch-Ramon, V. E-mail: jogler@mppmu.mpg.de; and others

    2012-02-10

    We present very high energy (E > 100 GeV) {gamma}-ray observations of the {gamma}-ray binary system LS I +61 Degree-Sign 303 obtained with the MAGIC stereo system between 2009 October and 2010 January. We detect a 6.3{sigma} {gamma}-ray signal above 400 GeV in the combined data set. The integral flux above an energy of 300 GeV is F(E > 300 GeV) = (1.4 {+-} 0.3{sub stat} {+-} 0.4{sub syst}) Multiplication-Sign 10{sup -12} cm{sup -2} s{sup -1}, which corresponds to about 1.3% of the Crab Nebula flux in the same energy range. The orbit-averaged flux of LS I +61 Degree-Sign 303 in the orbital phase interval 0.6-0.7, where a maximum of the TeV flux is expected, is lower by almost an order of magnitude compared to our previous measurements between 2005 September and 2008 January. This provides evidence for a new low-flux state in LS I +61 Degree-Sign 303. We find that the change to the low-flux state cannot be solely explained by an increase of photon-photon absorption around the compact star.

  14. 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.

  15. Discriminating ultrasonic proximity detection system

    DOEpatents

    Annala, Wayne C.

    1989-01-01

    This invention uses an ultrasonic transmitter and receiver and a microprocessor to detect the presence of an object. In the reset mode the invention uses a plurality of echoes from each ultrasonic burst to create a reference table of the echo-burst-signature of the empty monitored environment. The invention then processes the reference table so that it only uses the most reliable data. In the detection mode the invention compares the echo-burst-signature of the present environment with the reference table, detecting an object if there is a consistent difference between the echo-burst-signature of the empty monitored environment recorded in the reference table and the echo-burst-signature of the present environment.

  16. A system for the measurement of delayed neutrons and gammas from special nuclear materials

    SciTech Connect

    Andrews, M. T.; Corcoran, E. C.; Goorley, J. T.; Kelly, D. G.

    2014-11-27

    The delayed neutron counting (DNC) system at the Royal Military College of Canada has been upgraded to accommodate concurrent delayed neutron and gamma measurements. This delayed neutron and gamma counting (DNGC) system uses a SLOWPOKE-2 reactor to irradiate fissile materials before their transfer to a counting arrangement consisting of six ³He and one HPGe detector. The application of this system is demonstrated in an example where delayed neutron and gamma emissions are used in complement to examine ²³³U content and determine fissile mass with an average relative error and accuracy of -2.2 and 1.5 %, respectively.

  17. A system for the measurement of delayed neutrons and gammas from special nuclear materials

    DOE PAGESBeta

    Andrews, M. T.; Corcoran, E. C.; Goorley, J. T.; Kelly, D. G.

    2015-03-01

    The delayed neutron counting (DNC) system at the Royal Military College of Canada has been upgraded to accommodate concurrent delayed neutron and gamma measurements. This delayed neutron and gamma counting (DNGC) system uses a SLOWPOKE-2 reactor to irradiate fissile materials before their transfer to a counting arrangement consisting of six ³He and one HPGe detector. The application of this system is demonstrated in an example where delayed neutron and gamma emissions are used in complement to examine ²³³U content and determine fissile mass with an average relative error and accuracy of -2.2 and 1.5 %, respectively.

  18. Gamma Large Area Silicon Telescope (GLAST): Applying silicon strip detector technology to the detection of gamma rays in space

    SciTech Connect

    Atwood, W.B.; The GLAST Collaboration

    1993-06-01

    The recent discoveries and excitement generated by space satellite experiment EGRET (presently operating on Compton Gamma Ray Observatory -- CGRO) have prompted an investigation into modern detector technologies for the next generation space based gamma ray telescopes. The GLAST proposal is based on silicon strip detectors as the {open_quotes}technology of choice{close_quotes} for space application: no consumables, no gas volume, robust (versus fragile), long lived, and self triggerable. The GLAST detector basically has two components: a tracking module preceding a calorimeter. The tracking module has planes of crossed strip (x,y) 300 {mu}m pitch silicon detectors coupled to a thin radiator to measure the coordinates of converted electron-positron pairs. The gap between the layers ({approximately}5 cm) provides a lever arm for track fitting resulting in an angular resolution of <0.1{degree} at high energy. The status of this R & D effort is discussed including details on triggering the instrument, the organization of the detector electronics and readout, and work on computer simulations to model this instrument.

  19. Airborne change detection system for the detection of route mines

    NASA Astrophysics Data System (ADS)

    Donzelli, Thomas P.; Jackson, Larry; Yeshnik, Mark; Petty, Thomas E.

    2003-09-01

    The US Army is interested in technologies that will enable it to maintain the free flow of traffic along routes such as Main Supply Routes (MSRs). Mines emplaced in the road by enemy forces under cover of darkness represent a major threat to maintaining a rapid Operational Tempo (OPTEMPO) along such routes. One technique that shows promise for detecting enemy mining activity is Airborne Change Detection, which allows an operator to detect suspicious day-to-day changes in and around the road that may be indicative of enemy mining. This paper presents an Airborne Change Detection that is currently under development at the US Army Night Vision and Electronic Sensors Directorate (NVESD). The system has been tested using a longwave infrared (LWIR) sensor on a vertical take-off and landing unmanned aerial vehicle (VTOL UAV) and a midwave infrared (MWIR) sensor on a fixed wing aircraft. The system is described and results of the various tests conducted to date are presented.

  20. Gamma ray astronomy. [source mechanisms review

    NASA Technical Reports Server (NTRS)

    Fichtel, C. E.; Kniffen, D.

    1974-01-01

    The various source mechanisms for celestial gamma rays are reviewed. The gamma-ray data are examined as a source of information about the processes and source locations for the production of charged particle cosmic rays, galactic structure, explosive nucleosynthesis in supernovae, regions of confinement for cosmic rays, regions where matter-antimatter annihilation occurs, and the general condition in cosmological space both in the past and present. Topics include gamma rays from pi mesons by nuclear interactions, nuclear and supernovae lines, diffuse emission and discrete sources, interstellar absorption and detection of gamma rays, and others. A brief view of the available gamma-ray detection systems and techniques is presented.

  1. Disposable surface plasmon resonance aptasensor with membrane-based sample handling design for quantitative interferon-gamma detection.

    PubMed

    Chuang, Tsung-Liang; Chang, Chia-Chen; Chu-Su, Yu; Wei, Shih-Chung; Zhao, Xi-hong; Hsueh, Po-Ren; Lin, Chii-Wann

    2014-08-21

    ELISA and ELISPOT methods are utilized for interferon-gamma (IFN-γ) release assays (IGRAs) to detect the IFN-γ secreted by T lymphocytes. However, the multi-step protocols of the assays are still performed with laboratory instruments and operated by well-trained people. Here, we report a membrane-based microfluidic device integrated with a surface plasmon resonance (SPR) sensor to realize an easy-to-use and cost effective multi-step quantitative analysis. To conduct the SPR measurements, we utilized a membrane-based SPR sensing device in which a rayon membrane was located 300 μm under the absorbent pad. The basic equation covering this type of transport is based on Darcy's law. Furthermore, the concentration of streptavidin delivered from a sucrose-treated glass pad placed alongside the rayon membrane was controlled in a narrow range (0.81 μM ± 6%). Finally, the unbound molecules were removed by a washing buffer that was pre-packed in the reservoir of the chip. Using a bi-functional, hairpin-shaped aptamer as the sensing probe, we specifically detected the IFN-γ and amplified the signal by binding the streptavidin. A high correlation coefficient (R(2) = 0.995) was obtained, in the range from 0.01 to 100 nM. A detection limit of 10 pM was achieved within 30 min. Thus, the SPR assay protocols for IFN-γ detection could be performed using this simple device without an additional pumping system. PMID:24931052

  2. Development of gamma-photon/Cerenkov-light hybrid system for simultaneous imaging of I-131 radionuclide

    NASA Astrophysics Data System (ADS)

    Yamamoto, Seiichi; Suzuki, Mayumi; Kato, Katsuhiko; Watabe, Tadashi; Ikeda, Hayato; Kanai, Yasukazu; Ogata, Yoshimune; Hatazawa, Jun

    2016-09-01

    Although iodine 131 (I-131) is used for radionuclide therapy, high resolution images are difficult to obtain with conventional gamma cameras because of the high energy of I-131 gamma photons (364 keV). Cerenkov-light imaging is a possible method for beta emitting radionuclides, and I-131 (606 MeV maximum beta energy) is a candidate to obtain high resolution images. We developed a high energy gamma camera system for I-131 radionuclide and combined it with a Cerenkov-light imaging system to form a gamma-photon/Cerenkov-light hybrid imaging system to compare the simultaneously measured images of these two modalities. The high energy gamma imaging detector used 0.85-mm×0.85-mm×10-mm thick GAGG scintillator pixels arranged in a 44×44 matrix with a 0.1-mm thick reflector and optical coupled to a Hamamatsu 2 in. square position sensitive photomultiplier tube (PSPMT: H12700 MOD). The gamma imaging detector was encased in a 2 cm thick tungsten shield, and a pinhole collimator was mounted on its top to form a gamma camera system. The Cerenkov-light imaging system was made of a high sensitivity cooled CCD camera. The Cerenkov-light imaging system was combined with the gamma camera using optical mirrors to image the same area of the subject. With this configuration, we simultaneously imaged the gamma photons and the Cerenkov-light from I-131 in the subjects. The spatial resolution and sensitivity of the gamma camera system for I-131 were respectively ~3 mm FWHM and ~10 cps/MBq for the high sensitivity collimator at 10 cm from the collimator surface. The spatial resolution of the Cerenkov-light imaging system was 0.64 mm FWHM at 10 cm from the system surface. Thyroid phantom and rat images were successfully obtained with the developed gamma-photon/Cerenkov-light hybrid imaging system, allowing direct comparison of these two modalities. Our developed gamma-photon/Cerenkov-light hybrid imaging system will be useful to evaluate the advantages and disadvantages of these two

  3. Thermal systems for landmine detection

    NASA Astrophysics Data System (ADS)

    D'Angelo, Marco; Del Vecchio, Luca; Esposito, Salvatore; Balsi, Marco; Jankowski, Stanislaw

    2009-06-01

    This paper presents new techniques of landmine detection and localization using thermal methods. Described methods use both dynamical and static analysis. The work is based on datasets obtained from the Humanitarian Demining Laboratory of Università La Sapienza di Roma, Italy.

  4. Forward Obstacle Detection System by Stereo Vision

    NASA Astrophysics Data System (ADS)

    Iwata, Hiroaki; Saneyoshi, Keiji

    Forward obstacle detection is needed to prevent car accidents. We have developed forward obstacle detection system which has good detectability and the accuracy of distance only by using stereo vision. The system runs in real time by using a stereo processing system based on a Field-Programmable Gate Array (FPGA). Road surfaces are detected and the space to drive can be limited. A smoothing filter is also used. Owing to these, the accuracy of distance is improved. In the experiments, this system could detect forward obstacles 100 m away. Its error of distance up to 80 m was less than 1.5 m. It could immediately detect cutting-in objects.

  5. Toward detecting deception in intelligent systems

    NASA Astrophysics Data System (ADS)

    Santos, Eugene, Jr.; Johnson, Gregory, Jr.

    2004-08-01

    Contemporary decision makers often must choose a course of action using knowledge from several sources. Knowledge may be provided from many diverse sources including electronic sources such as knowledge-based diagnostic or decision support systems or through data mining techniques. As the decision maker becomes more dependent on these electronic information sources, detecting deceptive information from these sources becomes vital to making a correct, or at least more informed, decision. This applies to unintentional disinformation as well as intentional misinformation. Our ongoing research focuses on employing models of deception and deception detection from the fields of psychology and cognitive science to these systems as well as implementing deception detection algorithms for probabilistic intelligent systems. The deception detection algorithms are used to detect, classify and correct attempts at deception. Algorithms for detecting unexpected information rely upon a prediction algorithm from the collaborative filtering domain to predict agent responses in a multi-agent system.

  6. Comparison of thunderstorm systems that produce or lack RHESSI identified terrestrial gamma ray flashes

    NASA Astrophysics Data System (ADS)

    Splitt, M. E.; Barnes, D. E.; Dwyer, J. R.; Rassoul, H.; Lazarus, S. M.; Smith, D. M.; Cramer, E. S.; Schaal, M.; Saleh, Z. H.; Ulrich, W.; Grefenstette, B.; Hazelton, B. J.

    2009-12-01

    Thunderstorms associated with RHESSI-identified terrestrial gamma-ray flashes (TGFs) tend to be tall tropical thunderstorms in regions of significant lower tropospheric convergence. Yet despite the frequent occurrence of thunderstorms with these attributes within the RHESSI footprint, TGF detection is relatively rare. Tropical Rainfall Measuring Mission (TRMM) data that sync, in both space and time, with RHESSI, are used to determine whether there are observable differences between thunderstorm systems in which the RHESSI observes a TGF and those that it does not. In particular, TRMM Lightning Imaging Sensor (LIS) data are used to identify electrically active, but non-TGF producing, thunderstorms within a RHESSI footprint . TRMM precipitation and cloud-derived products from the null events are analyzed and compared to the same products composited from TGF producing storms. In addition, observations collected as part of the recent Airborne Detector for Energetic Lightning Emissions (ADELE) project are analyzed in this context.

  7. Evaluation of 3D Gamma index calculation implemented in two commercial dosimetry systems

    NASA Astrophysics Data System (ADS)

    Xing, Aitang; Arumugam, Sankar; Deshpande, Shrikant; George, Armia; Vial, Philip; Holloway, Lois; Goozee, Gary

    2015-01-01

    3D Gamma index is one of the metrics which have been widely used for clinical routine patient specific quality assurance for IMRT, Tomotherapy and VMAT. The algorithms for calculating the 3D Gamma index using global and local methods implemented in two software tools: PTW- VeriSoft® as a part of OCTIVIUS 4D dosimeter systems and 3DVHTM from Sun Nuclear were assessed. The Gamma index calculated by the two systems was compared with manual calculated for one data set. The Gamma pass rate calculated by the two systems was compared using 3%/3mm, 2%/2mm, 3%/2mm and 2%/3mm for two additional data sets. The Gamma indexes calculated by the two systems were accurate, but Gamma pass rates calculated by the two software tools for same data set with the same dose threshold were different due to the different interpolation of raw dose data by the two systems and different implementation of Gamma index calculation and other modules in the two software tools. The mean difference was -1.3%±3.38 (1SD) with a maximum difference of 11.7%.

  8. Experimental and Calculation Study of Absolute Efficiency of {gamma}-Ray Detection with the Coaxial HPGe-Detector GC 5019 at E{gamma}=0.24-18.565 MeV

    SciTech Connect

    Generalov, L.N.; Lebedev, B.L.; Livke, A.V.; Modenov, A.B.; Chirkin, V.A.

    2005-05-24

    In the range E{gamma}=0.24-18.565 MeV investigations were carried out of the absolute efficiency of {gamma}-ray detection with the HPGe-detector GC 5019 (CANBERRA). The investigations were performed in connection with measurements of proton radiation capture reaction cross sections on the lightest nuclei.

  9. Properties of terrestrial gamma ray flashes detected by AGILE MCAL below 30 MeV

    NASA Astrophysics Data System (ADS)

    Marisaldi, M.; Fuschino, F.; Tavani, M.; Dietrich, S.; Price, C.; Galli, M.; Pittori, C.; Verrecchia, F.; Mereghetti, S.; Cattaneo, P. W.; Colafrancesco, S.; Argan, A.; Labanti, C.; Longo, F.; Del Monte, E.; Barbiellini, G.; Giuliani, A.; Bulgarelli, A.; Campana, R.; Chen, A.; Gianotti, F.; Giommi, P.; Lazzarotto, F.; Morselli, A.; Rapisarda, M.; Rappoldi, A.; Trifoglio, M.; Trois, A.; Vercellone, S.

    2014-02-01

    We present the characteristics of 308 terrestrial gamma ray flashes (TGFs) detected by the Minicalorimeter (MCAL) instrument on board the AGILE satellite during the period March 2009-July 2012 in the ±2.5° latitude band and selected to have the maximum photon energy up to 30 MeV. The characteristics of the AGILE events are analyzed and compared to the observational framework established by the two other currently active missions capable of detecting TGFs from space, RHESSI and Fermi. A detailed model of the MCAL dead time is presented, which is fundamental to properly interpret our observations. The most significant contribution to dead time is due to the anticoincidence shield in its current configuration and not to the MCAL detector itself. Longitude and local time distributions are compatible with previous observations, while the duration distribution is biased toward longer values because of dead time. The intensity distribution is compatible with previous observations, when dead time is taken into account. The TGFs cumulative spectrum supports a low production altitude, in agreement with previous measurements. We also compare our sample to lightning sferics detected by the World Wide Lightning Location Network and suggest a new method to assess quantitatively the consistency of two TGF populations based on the comparison of the associated lightning activity. According to this method, AGILE and RHESSI samples are compatible with the same parent population. The AGILE TGF catalog below 30 MeV is accessible online at the website of the ASI Science Data Center http://www.asdc.asi.it/mcaltgfcat/.

  10. Detection of Three Gamma-ray Burst Host Galaxies at z ˜ 6

    NASA Astrophysics Data System (ADS)

    McGuire, J. T. W.; Tanvir, N. R.; Levan, A. J.; Trenti, M.; Stanway, E. R.; Shull, J. M.; Wiersema, K.; Perley, D. A.; Starling, R. L. C.; Bremer, M.; Stocke, J. T.; Hjorth, J.; Rhoads, J. E.; Curtis-Lake, E.; Schulze, S.; Levesque, E. M.; Robertson, B.; Fynbo, J. P. U.; Ellis, R. S.; Fruchter, A. S.

    2016-07-01

    Long-duration gamma-ray bursts (GRBs) allow us to pinpoint and study star-forming galaxies in the early universe, thanks to their orders of magnitude brighter peak luminosities compared to other astrophysical sources, and their association with the deaths of massive stars. We present Hubble Space Telescope Wide Field Camera 3 detections of three Swift GRB host galaxies lying at redshifts z = 5.913 (GRB 130606A), z = 6.295 (GRB 050904), and z = 6.327 (GRB 140515A) in the F140W (wide-JH band, {λ }{{obs}}˜ 1.4 μ {{m}}) filter. The hosts have magnitudes (corrected for Galactic extinction) of {m}{λ {obs},{AB}}={26.34}-0.16+0.14,{27.56}-0.22+0.18, and {28.30}-0.33+0.25, respectively. In all three cases, the probability of chance coincidence of lower redshift galaxies is ≲ 2 % , indicating that the detected galaxies are most likely the GRB hosts. These are the first detections of high-redshift (z\\gt 5) GRB host galaxies in emission. The galaxies have luminosities in the range 0.1–0.6 {L}z=6* (with {M}1600* =-20.95+/- 0.12) and half-light radii in the range 0.6–0.9 {{kpc}}. Both their half-light radii and luminosities are consistent with existing samples of Lyman-break galaxies at z˜ 6. Spectroscopic analysis of the GRB afterglows indicate low metallicities ([{{M/H}}]≲ -1) and low dust extinction ({A}{{V}}≲ 0.1) along the line of sight. Using stellar population synthesis models, we explore the implications of each galaxy’s luminosity for its possible star-formation history and consider the potential for emission line metallicity determination with the upcoming James Webb Space Telescope.

  11. AZ-101 Mixer Pump Demonstration Data Acquisition System and Gamma Cart Data Acquisition Control System Software Configuration Management Plan

    SciTech Connect

    WHITE, D.A.

    1999-12-29

    This Software Configuration Management Plan (SCMP) provides the instructions for change control of the AZ1101 Mixer Pump Demonstration Data Acquisition System (DAS) and the Sludge Mobilization Cart (Gamma Cart) Data Acquisition and Control System (DACS).

  12. Detecting changes in maps of gamma spectra with Kolmogorov-Smirnov tests

    NASA Astrophysics Data System (ADS)

    Reinhart, Alex; Ventura, Valérie; Athey, Alex

    2015-12-01

    Various security, regulatory, and consequence management agencies are interested in continuously monitoring wide areas for unexpected changes in radioactivity. Existing detection systems are designed to search for radioactive sources but are not suited to repeat mapping and change detection. Using a set of daily spectral observations collected at the Pickle Research Campus, we improved on the prior Spectral Comparison Ratio Anomaly Mapping (SCRAM) algorithm and developed a new method based on two-sample Kolmogorov-Smirnov tests to detect sudden spectral changes. We also designed simulations and visualizations of statistical power to compare methods and guide deployment scenarios.

  13. Data acquisition system and ground calibration of polarized gamma-ray observer (PoGOLite)

    NASA Astrophysics Data System (ADS)

    Takahashi, Hiromitsu; Chauvin, Maxime; Fukazawa, Yasushi; Jackson, Miranda; Kamae, Tuneyoshi; Kawano, Takafumi; Kiss, Mozsi; Kole, Merlin; Mikhalev, Victor; Mizuno, Tsunefumi; Moretti, Elena; Pearce, Mark; Rydström, Stefan

    2014-07-01

    The Polarized Gamma-ray Observer, PoGOLite, is a balloon experiment with the capability of detecting 10% polarization from a 200 mCrab celestial object between the energy-range 25-80 keV in one 6 hour flight. Polarization measurements in soft gamma-rays are expected to provide a powerful probe into high-energy emission mechanisms in/around neutron stars, black holes, supernova remnants, active-galactic nuclei etc. The "pathfinder" flight was performed in July 2013 for 14 days from Sweden to Russia. The polarization is measured using Compton scattering and photoelectric absorption in an array of 61 well-type phoswich detector cells (PDCs) for the pathfinder instrument. The PDCs are surrounded by 30 BGO crystals which form a side anti-coincidence shield (SAS) and passive polyethylene neutron shield. There is a neutron detector consisting of LiCaAlF6 (LiCAF) scintillator covered with BGOs to measure the background contribution of atmospheric neutrons. The data acquisition system treats 92 PMT signals from 61 PDCs + 30 SASs + 1 neutron detector, and it is developed based on SpaceWire spacecraft communication network. Most of the signal processing is done by digital circuits in Field Programmable Gate Arrays (FPGAs). This enables the reduction of the mass, the space and the power consumption. The performance was calibrated before the launch.

  14. Hydrogen Fire Detection System Features Sharp Discrimination

    NASA Technical Reports Server (NTRS)

    Bright, C. S.

    1966-01-01

    Hydrogen fire detection system discovers fires by detecting the flickering ultraviolet radiation emitted by the OH molecule, a short-lived intermediate combustion product found in hydrogen-air flames. In a space application, the system discriminates against false signals from sunlight and rocket engine exhaust plume radiation.

  15. Multi-gamma-source CT imaging system: a feasibility study with the Poisson noise

    NASA Astrophysics Data System (ADS)

    Wi, Sunhee; Cho, Seungryong

    2016-03-01

    This study was performed to test the feasibility of multi-gamma-source CT imaging system. Gamma-source CT employs radioisotopes that emit monochromatic energy gamma-rays. The advantages of gamma-source CT include its immunity to beam hardening artifacts, its capacity of quantitative CT imaging, and its higher performance in low contrast imaging compared to the conventional x-ray CT. Radioisotope should be shielded by use of a pin-hole collimator so as to make a fine focal spot. Due to its low gamma-ray flux in general, the reconstructed image from a single gamma-source CT would suffer from high noise in data. To address this problem, we proposed a multi-gamma source CT imaging system and developed an iterative image reconstruction algorithm accordingly in this work. Conventional imaging model assumes a single linear imaging system typically represented by Mf = g. In a multi-gamma-source CT system however, the inversion problem is not any more based on a single linear system since one cannot separate a detector pixel value into multiple ones that are corresponding to each rays from the sources. Instead, the imaging model can be constructed by a set of linear system models each of which assumes an estimated measurement g. Based on this model, the proposed algorithm has a weighting step which distributes each projection data into multiple estimated measurements. We used two gamma sources at various positions and with varying intensities in this numerical study to demonstrate its feasibility. Therefore, the measured projection data(g) is separated into each estimated projection data(g1, g2) in this study. The proposed imaging protocol is believed to contribute to both medical and industrial applications.

  16. New GRB Candidates as Detected by the Fermi Gamma-ray Space Telescope, January-June 2011

    NASA Astrophysics Data System (ADS)

    Robinson, Rebecca

    2012-01-01

    After analyzing data collected by the Fermi Gamma Ray Space Telescope GLAST Burst Monitor (GBM), operated by NASA in cooperation with the US Department of Energy, we focus on gamma ray events from January to June in the year 2011. A portion of these events were detected in concordance with events that have already been reported, and the others are to be announced in this report. For each event, an energy spectrum was generated using a trigger-search computer algorithm and these spectra were divided into several categories for further analysis. In some cases, intriguing spectral lines, including a 511 keV line, were detected; implications and analysis of these known and previously unknown detections are discussed in this report.

  17. Early-time observations of gamma-ray burst error boxes with the Livermore optical transient imaging system

    SciTech Connect

    Williams, G G

    2000-08-01

    Despite the enormous wealth of gamma-ray burst (GRB) data collected over the past several years the physical mechanism which causes these extremely powerful phenomena is still unknown. Simultaneous and early time optical observations of GRBs will likely make an great contribution t o our understanding. LOTIS is a robotic wide field-of-view telescope dedicated to the search for prompt and early-time optical afterglows from gamma-ray bursts. LOTIS began routine operations in October 1996 and since that time has responded to over 145 gamma-ray burst triggers. Although LOTIS has not yet detected prompt optical emission from a GRB its upper limits have provided constraints on the theoretical emission mechanisms. Super-LOTIS, also a robotic wide field-of-view telescope, can detect emission 100 times fainter than LOTIS is capable of detecting. Routine observations from Steward Observatory's Kitt Peak Station will begin in the immediate future. During engineering test runs under bright skies from the grounds of Lawrence Livermore National Laboratory Super-LOTIS provided its first upper limits on the early-time optical afterglow of GRBs. This dissertation provides a summary of the results from LOTIS and Super-LOTIS through the time of writing. Plans for future studies with both systems are also presented.

  18. [Detection of gamma-interferon mRNA in JEG-3 choriocarcinoma cell line by means of polymerase chain reaction].

    PubMed

    Fülöp, V; Szigetvári, I; Szepesi, J; Gáti, I

    1994-05-01

    To investigate the pathogenesis of choriocarcinoma the authors employed a newly developed gene amplification method by reverse polymerase chain reaction for the detection of gamma-interferon messenger RNA in JEG-3 choriocarcinoma cell line. Polymerase chain reaction products were analysed by agarose gel electrophoresis. Using 1 Kb DNA ladder as a marker, 84 base-pair fragment was selectively amplified correlating with published gamma-interferon gene fragment length. Because cDNA contains a virtually complete copy of the mRNA this method provides an evidence for the expression of gamma-interferon gene in JEG-3 choriocarcinoma cell line. Based on these results a potential autocrine mechanism may be present in JEG-3 choriocarcinoma cell line. PMID:8183543

  19. Fermi-LAT detection of increased gamma-ray activity from the blazar PKS 0727-115

    NASA Astrophysics Data System (ADS)

    Horan, D.; Hays, E. Gurwell, Mark A.

    2009-01-01

    The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope (formerly GLAST, launched June 11, 2008), has observed an increasing gamma-ray flux from a source positionally consistent with PKS 0727-115 (RA: 07h30m19.1s, Dec: -11d41m13s, J2000, z=1.59 ( Zensus et al. 2002)). Preliminary analysis indicates that over the past month the source has become, on average, brighter with a gamma-ray flux (E>100MeV) of approximately 5.0+/- 0.8 x 10^-7 photons cm^-2 s^-1 on weekly timescales and occasional day-scale detections at the level of approximately 4.0 +/- 1.0 x 10^-7 photons cm^-2 s^-1.

  20. The Advanced Gamma-ray Imaging System (AGIS)--Science Highlights

    SciTech Connect

    Buckley, J.; Krawczynski, H.; Coppi, P.; Digel, S.; Funk, S.; Krennrich, F.; Pohl, M.; Romani, R.; Vassiliev, V.

    2008-12-24

    The Advanced Gamma-ray Imaging System (AGIS), a future gamma-ray telescope consisting of an array of {approx}50 atmospheric Cherenkov telescopes distributed over an area of {approx}1 km{sup 2}, will provide a powerful new tool for exploring the high-energy universe. The order-of-magnitude increase in sensitivity and improved angular resolution could provide the first detailed images of {gamma}-ray emission from other nearby galaxies or galaxy clusters. The large effective area will provide unprecedented sensitivity to short transients (such as flares from AGNs and GRBs) probing both intrinsic spectral variability (revealing the details of the acceleration mechanism and geometry) as well as constraining the high-energy dispersion in the velocity of light (probing the structure of spacetime and Lorentz invariance). A wide field of view ({approx}4 times that of current instruments) and excellent angular resolution (several times better than current instruments) will allow for an unprecedented survey of the Galactic plane, providing a deep unobscured survey of SNRs, X-ray binaries, pulsar-wind nebulae, molecular cloud complexes and other sources. The differential flux sensitivity of {approx}10{sup -13} erg cm{sup -2} sec{sup -1} will rival the most sensitive X-ray instruments for these extended Galactic sources. The excellent capabilities of AGIS at energies below 100 GeV will provide sensitivity to AGN and GRBs out to cosmological redshifts, increasing the number of AGNs detected at high energies from about 20 to more than 100, permitting population studies that will provide valuable insights into both a unified model for AGN and a detailed measurement of the effects of intergalactic absorption from the diffuse extragalactic background light. A new instrument with fast-slewing wide-field telescopes could provide detections of a number of long-duration GRBs providing important physical constraints from this new spectral component. The new array will also have excellent

  1. Development of transportable gamma-ray tomographic system for industrial application

    NASA Astrophysics Data System (ADS)

    Kim, Jongbum; Jung, Sung-hee; Moon, Jinho; Guen Park, Jang; Jin, Joonha; Cho, Gyuseong

    2012-11-01

    This paper introduces a gamma-ray tomographic system which is transportable and can be used for on-line systems such as a pipeline operation. In a previous study, a feasibility study on a gamma-ray tomographic system with a scanning geometry of Electron Beam CT was carried out by Monte Carlo simulation. This paper contains a successive work on a previous study by developing and evaluating a real system. To construct a gamma-ray CT, 137Cs was used as a gamma-ray source and radiation measurement system with 72 channel CsI detectors whose crystal is a 12 mm×12 mm×20 mm rectangular parallelepiped was developed to operate jointly with a motion control system. ML-EM algorithm was used for image reconstruction of experimental data. Using the developed transportable gamma-ray system, laboratory and field experiments were carried out successfully. The field experiment results show that a gamma-ray CT with an Electron Beam CT scanning geometry can be a transportable gantry for objects which are parts of processes.

  2. Real time method and computer system for identifying radioactive materials from HPGe gamma-ray spectroscopy

    DOEpatents

    Rowland, Mark S.; Howard, Douglas E.; Wong, James L.; Jessup, James L.; Bianchini, Greg M.; Miller, Wayne O.

    2007-10-23

    A real-time method and computer system for identifying radioactive materials which collects gamma count rates from a HPGe gamma-radiation detector to produce a high-resolution gamma-ray energy spectrum. A library of nuclear material definitions ("library definitions") is provided, with each uniquely associated with a nuclide or isotope material and each comprising at least one logic condition associated with a spectral parameter of a gamma-ray energy spectrum. The method determines whether the spectral parameters of said high-resolution gamma-ray energy spectrum satisfy all the logic conditions of any one of the library definitions, and subsequently uniquely identifies the material type as that nuclide or isotope material associated with the satisfied library definition. The method is iteratively repeated to update the spectrum and identification in real time.

  3. Measurements of gamma-ray production cross sections for shielding materials of space nuclear systems

    NASA Technical Reports Server (NTRS)

    Orphan, V. J.; John, J.; Hoot, C. G.

    1972-01-01

    Measurements of secondary gamma ray production from neutron interactions have been made over the entire energy range of interest in shielding applications. The epithermal capture gamma ray yields for both resolved gamma ray lines and continuum have been measured from thermal energies to 100 KeV for natural tungsten and U-238, two important candidate shield materials in SNAP reactor systems. Data are presented to illustrate the variation of epithermal capture gamma ray yields with neutron energy. The gamma ray production cross sections from (n,xy) reactions have been measured for Fe and Al from the threshold energies for inelastic scattering to approximately 16 MeV. Typical Fe and Al cross sections obtained with high-neutron energy resolution and averaged over broad neutron-energy groups are presented.

  4. SU-E-T-186: Feasibility Study of Glass Cherenkov Detector for Prompt Gamma Detection in Proton Therapy

    SciTech Connect

    Lau, A; Chen, Y; Ahmad, S

    2014-06-01

    Purpose: To simulate a Cherenkov glass detector system utilizing prompt gamma (PG) technique to quantify range uncertainties in proton radiation therapy. Methods: A simulation of high energy photons typically produced in proton interactions with materials incident onto a block of Cherenkov glass was performed with the Geant4 toolkit. The standard electromagnetic package was used along with several decay modules (G4Decay, G4DecayPhysics, and G4RadioactiveDecayPhysics) and the optical photon components (G4OpticalPhysics). Our setup included a pencil beam consisting of a hundred thousand 6 MeV photons (approximately the deexcitation energy released from 16O) incident onto a 2.5 ⊗ 2.5 ⊗ 1.5 cm3 of a Cherenkov glass (7.2 g of In2O3 + 90 g cladding, density of 2.82 g/cm3, Zeff = 33.7, index of refraction 1.56). The energy deposited from incident 6 MeV photons as well as secondary electrons and resulting optical photons were recorded. Results: The energy deposited by 6 MeV photons in glass material showed several peaks that included the photoelectric, the single and double escape peaks. About 11% of incident photons interacted with glass material to deposit energy. Most of the photons collected were in the region of double escape peak (approximately 4.98 MeV). The secondary electron spectrum produced from incident photons showed a high energy peak located near 6 MeV and a sharp peak located ∼120 keV with a continuous distribution between these two points. The resulting Cherenkov photons produced showed a continuous energy distribution between 2 and 5 eV with a slight increase in yield beginning about 3 eV. The amount of Cherenkov photons produced per interacting incident 6 MeV photon was ∼240.7. Conclusion: This study suggests the viability of utilizing the Cherenkov glass material as a possible prompt gamma photon detection device. Future work will include optimization of the detector system to maximize photon detection efficiency.

  5. Validation of Non-Invasive Waste Assay System (Gamma Box Counter) Performance at AECL Whiteshell Laboratories - 13136

    SciTech Connect

    Attas, E.M.; Bialas, E.; Rhodes, M.J.

    2013-07-01

    Low-level radioactive waste (LLW) in solid form, resulting from decommissioning and operations activities at AECL's Whiteshell Laboratories (WL), is packaged in B-25 and B-1000 standard waste containers and characterized before it is shipped to an on-site interim storage facility, pending AECL decisions on long term management of its LLW. Assay of the waste packages before shipment contributes to an inventory of the interim storage facility and provides data to support acceptance at a future repository. A key characterization step is a gamma spectrometric measurement carried out under standard conditions using an automated, multi-detector Waste Assay System (WAS), purchased from Antech Corporation. A combination of ORTEC gamma acquisition software and custom software is used in this system to incorporate multiple measurements from two collimated high-resolution detectors. The software corrects the intensities of the gamma spectral lines for geometry and attenuation, and generates a table of calculated activities or limits of detection for a user-defined list of radioisotopes that may potentially be present. Validation of WAS performance was a prerequisite to routine operation. Documentation of the validation process provides assurance of the quality of the results produced, which may be needed one or two decades after they were generated. Aspects of the validation included setting up a quality control routine, measurements of standard point sources in reproducible positions, study of the gamma background, optimization of user-selectable software parameters, investigation of the effect of non-uniform distribution of materials and radionuclides, and comparison of results with measurements made using other gamma detector systems designed to assay bulk materials. The following key components of the validation process have been established. A daily quality control routine has been instituted, to verify stability of the gamma detector operation and the background levels

  6. Fermi LAT Observations of LS I +61 303: First Detection of an Orbital Modulation in GeV Gamma Rays

    SciTech Connect

    Abdo, A.A.; Ackermann, M.; Ajello, M.; Atwood, W.B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman, B.M.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R.; Bloom, E.D.; Bonamente, E.; Borgland, A.W.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; /more authors..

    2012-04-02

    This Letter presents the first results from the observations of LS I +61{sup o}303 using Large Area Telescope data from the Fermi Gamma-Ray Space Telescope between 2008 August and 2009 March. Our results indicate variability that is consistent with the binary period, with the emission being modulated at 26.6 {+-} 0.5 days. This constitutes the first detection of orbital periodicity in high-energy gamma rays (20 MeV-100 GeV, HE). The light curve is characterized by a broad peak after periastron, as well as a smaller peak just before apastron. The spectrum is best represented by a power law with an exponential cutoff, yielding an overall flux above 100 MeV of 0.82 {+-} 0.03(stat) {+-} 0.07(syst) 10{sup -6} ph cm{sup -2} s{sup -1}, with a cutoff at 6.3 {+-} 1.1(stat) {+-} 0.4(syst) GeV and photon index {Gamma} = 2.21 {+-} 0.04(stat) {+-} 0.06(syst). There is no significant spectral change with orbital phase. The phase of maximum emission, close to periastron, hints at inverse Compton scattering as the main radiation mechanism. However, previous very high-energy gamma ray (>100 GeV, VHE) observations by MAGIC and VERITAS show peak emission close to apastron. This and the energy cutoff seen with Fermi suggest that the link between HE and VHE gamma rays is nontrivial.

  7. Morphometric analysis in gamma-ray astronomy using Minkowski functionals. Source detection via structure quantification

    NASA Astrophysics Data System (ADS)

    Göring, D.; Klatt, M. A.; Stegmann, C.; Mecke, K.

    2013-07-01

    Aims: H.E.S.S. observes an increasing number of large extended sources. A new technique based on the structure of the sky map is developed to account for these additional structures by comparing them with the common point source analysis. Methods: Minkowski functionals are powerful measures from integral geometry. They can be used to quantify the structure of the counts map, which is then compared with the expected structure of a pure Poisson background. Gamma-ray sources lead to significant deviations from the expected background structure. The standard likelihood ratio method is exclusively based on the number of excess counts and discards all further structure information of large extended sources. The morphometric data analysis incorporates this additional geometric information in an unbiased analysis, i.e., without the need of any prior knowledge about the source. Results: We have successfully applied our method to data of the H.E.S.S. experiment. The morphometric analysis presented here is dedicated to detecting faint extended sources.

  8. Direct Detection of Pu-242 with a Metallic Magnetic Calorimeter Gamma-Ray Detector

    NASA Astrophysics Data System (ADS)

    Bates, C.; Pies, C.; Kempf, S.; Hengstler, D.; Fleischmann, A.; Gastaldo, L.; Enss, C.; Friedrich, S.

    2016-07-01

    Cryogenic high-resolution γ -ray detectors can improve the accuracy of non-destructive assay (NDA) of nuclear materials in cases where conventional high-purity germanium detectors are limited by line overlap or by the Compton background. We have improved the performance of gamma detectors based on metallic magnetic calorimeters (MMCs) by separating the 0.5 × 2 × 0.25 mm3 Au absorber from the Au:Er sensor with sixteen 30-\\upmu m-diameter Au posts. This ensures that the entire γ -ray energy thermalizes in the absorber before heating the Au:Er sensor, and improves the energy resolution at 35 mK to as low as 90 eV FWHM at 60 keV. This energy resolution enables the direct detection of γ -rays from Pu-242, an isotope that cannot be measured by traditional NDA and whose concentration is therefore inferred through correlations with other Pu isotopes. The Pu-242 concentration of 11.11 ± 0.42 % measured by NDA with MMCs agrees with mass spectrometry results and exceeds the accuracy of correlation measurements.

  9. Detection and original dose assessment of egg powders subjected to gamma irradiation by using ESR technique

    NASA Astrophysics Data System (ADS)

    Aydın, Talat

    2015-09-01

    ESR (electron spin resonance) techniques were applied for detection and original dose estimation to radiation-processed egg powders. The un-irradiated (control) egg powders showed a single resonance line centered at g=2.0086±0.0005, 2.0081±0.0005, 2.0082±0.0005 (native signal) for yolk, white and whole egg, respectively. Irradiation induced at least one additional intense singlet overlapping to the control signal and caused a significant increase in signal intensity without any changes in spectral patterns. Responses of egg powders to different gamma radiation doses in the range 0-10 kGy were examined. The stability of the radiation-induced ESR signal of irradiated egg powders were investigated over a storage period of about 5 months. Additive reirradiation of the egg powders produces a reproducible dose response function, which can be used to assess the initial dose by back-extrapolation. The additive dose method gives an estimation of the original dose within ±12% at the end of the 720 h storage period.

  10. IMPLICATIONS OF UNDERSTANDING SHORT GAMMA-RAY BURSTS DETECTED BY SWIFT

    SciTech Connect

    Shao Lang; Fan Yizhong; Zhang Fuwen; Jin Zhiping; Wei Daming; Dai Zigao

    2011-09-01

    In an effort to understand the puzzle of classifying gamma-ray bursts (GRBs), we perform a systematic study of Swift GRBs and investigate several short GRB issues. Though short GRBs have a short ({approx}< 2 s) prompt duration as monitored by the Burst Alert Telescope, the composite light curves including both the prompt and afterglow emission suggest that most of the short GRBs have a similar radiative feature to long GRBs. Furthermore, some well-studied short GRBs might also have an intrinsically long prompt duration, which renders them as a type of short GRB imposters. Genuine short GRBs detected by Swift might be rare, so determining the observed short GRBs is, not surprisingly, troublesome. In particular, the observational biases in the host identification and redshift measurement of GRBs should be taken with great caution. The redshift distribution, which has been found to be different for long and short GRBs, might have been strongly affected by the measurement methods. We find that the redshifts measured from the presumed host galaxies of long and short GRBs appear to have a similar distribution.

  11. Gamma-ray and Radio Properties of Six Pulsars Detected by the Fermi Large Area Telescope

    NASA Astrophysics Data System (ADS)

    Weltevrede, P.; Abdo, A. A.; Ackermann, M.; Ajello, M.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman, B. M.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Burnett, T. H.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Camilo, F.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö.; Charles, E.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Ciprini, S.; Claus, R.; Cognard, I.; Cohen-Tanugi, J.; Cominsky, L. R.; Conrad, J.; Cutini, S.; Dermer, C. D.; Desvignes, G.; de Angelis, A.; de Luca, A.; de Palma, F.; Digel, S. W.; Dormody, M.; Silva, E. do Couto e.; Drell, P. S.; Dubois, R.; Dumora, D.; Farnier, C.; Favuzzi, C.; Fegan, S. J.; Focke, W. B.; Fortin, P.; Frailis, M.; Freire, P. C. C.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giavitto, G.; Giebels, B.; Giglietto, N.; Giordano, F.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grondin, M.-H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hanabata, Y.; Harding, A. K.; Hays, E.; Hobbs, G.; Hughes, R. E.; Jackson, M. S.; Jóhannesson, G.; Johnson, A. S.; Johnson, T. J.; Johnson, W. N.; Johnston, S.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kawai, N.; Keith, M.; Kerr, M.; Knödlseder, J.; Kocian, M. L.; Kramer, M.; Kuss, M.; Lande, J.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Lyne, A. G.; Makeev, A.; Manchester, R. N.; Mazziotta, M. N.; McEnery, J. E.; McGlynn, S.; Meurer, C.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Paneque, D.; Panetta, J. H.; Parent, D.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Piron, F.; Porter, T. A.; Rainò, S.; Rando, R.; Ransom, S. M.; Razzano, M.; Rea, N.; Reimer, A.; Reimer, O.; Reposeur, T.; Rochester, L. S.; Rodriguez, A. Y.; Romani, R. W.; Roth, M.; Ryde, F.; Sadrozinski, H. F.-W.; Sanchez, D.; Sander, A.; Saz Parkinson, P. M.; Sgrò, C.; Siskind, E. J.; Smith, D. A.; Smith, P. D.; Spandre, G.; Spinelli, P.; Stappers, B. W.; Strickman, M. S.; Suson, D. J.; Tajima, H.; Takahashi, H.; Tanaka, T.; Thayer, J. B.; Thayer, J. G.; Theureau, G.; Thompson, D. J.; Thorsett, S. E.; Tibaldo, L.; Torres, D. F.; Tosti, G.; Tramacere, A.; Uchiyama, Y.; Usher, T. L.; Van Etten, A.; Vasileiou, V.; Venter, C.; Vilchez, N.; Vitale, V.; Waite, A. P.; Wang, P.; Wang, N.; Watters, K.; Winer, B. L.; Wood, K. S.; Ylinen, T.; Ziegler, M.

    2010-01-01

    We report the detection of pulsed γ-rays for PSRs J0631+1036, J0659+1414, J0742-2822, J1420-6048, J1509-5850, and J1718-3825 using the Large Area Telescope on board the Fermi Gamma-ray Space Telescope (formerly known as GLAST). Although these six pulsars are diverse in terms of their spin parameters, they share an important feature: their γ-ray light curves are (at least given the current count statistics) single peaked. For two pulsars, there are hints for a double-peaked structure in the light curves. The shapes of the observed light curves of this group of pulsars are discussed in the light of models for which the emission originates from high up in the magnetosphere. The observed phases of the γ-ray light curves are, in general, consistent with those predicted by high-altitude models, although we speculate that the γ-ray emission of PSR J0659+1414, possibly featuring the softest spectrum of all Fermi pulsars coupled with a very low efficiency, arises from relatively low down in the magnetosphere. High-quality radio polarization data are available showing that all but one have a high degree of linear polarization. This allows us to place some constraints on the viewing geometry and aids the comparison of the γ-ray light curves with high-energy beam models.

  12. Detection of irradiated fresh fruits treated by e-beam or gamma rays

    NASA Astrophysics Data System (ADS)

    Marin-Huachaca, Nélida Simona; Lamy-Freund, Maria Tereza; Mancini-Filho, Jorge; Delincée, Henry; Villavicencio, Anna Lúcia C. H.

    2002-03-01

    Since about 1990, the amount of commercially irradiated food products available worldwide has increased. Commercial irradiation of foods has been allowed in Brazil since 1973 and now more than 20 different food products are approved. Among these products are a number of fresh fruits which may be irradiated for insect disinfestation, to delay ripening and to extend shelf-life. Today, there is a growing interest to apply radiation for the treatment of fruits instead of using fumigation or e.g. vapour-heat treatments, and an increased international trade in irradiated fruits is expected. To ensure free consumer choice, methods to identify irradiated foods are highly desirable. In this work, three detection methods for irradiated fruits have been employed: DNA Comet Assay, the half-embryo test and ESR. Both electron-beam (e-beam) and gamma rays were applied in order to compare the response with these two different kinds of radiation. Fresh fruits such as oranges, lemons, apples, watermelons and tomatoes were irradiated with doses in the range 0, 0.50, 0.75, 1.0, 2.0 and 4.0kGy. For analysis, the seeds of the fruits were utilized. Both DNA Comet Assay and the half-embryo test enabled an easy identification of the radiation treatment. However, under our conditions, ESR measurements were not satisfactory.

  13. Detectability of Planck-scale-induced Blurring with Gamma-ray Bursts

    NASA Astrophysics Data System (ADS)

    Steinbring, Eric

    2015-03-01

    Microscopic fluctuations inherent to the fuzziness of spacetime at the Planck scale might accumulate in wavefronts propagating a cosmological distance and lead to noticeable blurring in an image of a pointlike source. Distant quasars viewed in the optical and ultraviolet with Hubble Space Telescope (HST) may show this weakly, and if real suggests a stronger effect should be seen for gamma-ray bursts (GRBs) in X-rays and γ-rays. Those telescopes, however, operate far from their diffraction limits. A description of how Planck-scale-induced blurring could be sensed at high energy, including with cosmic rays, while still agreeing with the HST results is discussed. It predicts dilated apparent source size and inflated uncertainties in positional centroids, effectively a threshold angular accuracy restricting knowledge of source location on the sky. These outcomes are found to be consistent with an analysis of the 10 highest-redshift GRB detections reported for the Fermi satellite. Confusion with photon cascade and scattering phenomena is also possible; prospects for a definitive multiwavelength measurement are considered.

  14. Gamma-ray detection from gravitino dark matter decay in the μνSSM

    SciTech Connect

    Choi, Ki-Young; Muñoz, Carlos; López-Fogliani, Daniel E.; Austri, Roberto Ruiz de E-mail: d.lopez@sheffield.ac.uk E-mail: rruiz@ific.uv.es

    2010-03-01

    The μνSSM provides a solution to the μ-problem of the MSSM and explains the origin of neutrino masses by simply using right-handed neutrino superfields. Given that R-parity is broken in this model, the gravitino is a natural candidate for dark matter since its lifetime becomes much longer than the age of the Universe. We consider the implications of gravitino dark matter in the μνSSM, analyzing in particular the prospects for detecting gamma rays from decaying gravitinos. If the gravitino explains the whole dark matter component, a gravitino mass larger than 20GeV is disfavored by the isotropic diffuse photon background measurements. On the other hand, a gravitino with a mass range between 0.1−20 GeV gives rise to a signal that might be observed by the FERMI satellite. In this way important regions of the parameter space of the μνSSM can be checked.

  15. TV system for detection of latent fingerprints

    NASA Astrophysics Data System (ADS)

    Li, Ping; Ban, Xianfu; Liu, Shaowu; Ding, Zhenfang

    1993-04-01

    A fingerprint is reliable evidence for recognizing criminals in detecting cases. There are many conventional chemical and physical methods in detecting fingerprints. In this paper, a newly developed portable TV system for detecting a latent fingerprint is described. This system is suited for field reconnaissance of cases as well as for laboratory testing. It can display a latent fingerprint, which is hard to identify and even cannot be displayed by conventional methods, and it can detect prints or stamps which are faded, altered, or falsified, etc.

  16. Detection of Thermoluminescence in Post-Gamma Shelf-Aged Polyethylene

    NASA Astrophysics Data System (ADS)

    Gray, Jonathan; Shah Jahan, M.

    2004-11-01

    Polyethylene (PE) of molecular weight 3-6 million mol/gm, commonly known as ultra-high molecular weight PE (UHMWPE) and used in orthopedic joint replacements, was irradiated with gamma rays at sterilization dose ( ˜ 3 MRad of ^60Co) at room temperature (RT) in air and subsequently aged for 5-15 years in the same environment. When heated from RT to 280^oC at 1^oC/s using a commercial thermoluminescence (TL) detector (Harshaw 3500), the aged UHMWPE samples were found to produce luminescence with (glow) peaks near 112^oC, 208^oC and 255^oC. While the 112^oC TL glow peak is attributed to the long-lived oxygen-induced free radicals, the 208^oC and 255^oC glow peaks are assigned to molecular breakdown processes caused by melting of the long-chain molecules. To confirm the correlation between TL and the free radicals, measurements were made on the same samples before and after recording TL using an X-band (9.5 GHz microwave frequency and 100 kHz modulation and detection frequency) electron spin resonance (ESR) spectrometer (Varian E-4). Before TL, ESR produced a broad resonance line centered at g-value 2.013 and peak-to-peak separation of 5.26 G. After TL, a very weak broad ESR signal was detected which may be produced by molecular breakdown or free radicals still present in the sample.

  17. Bounds on Spectral Dispersion from Fermi-Detected Gamma Ray Bursts

    NASA Astrophysics Data System (ADS)

    Nemiroff, Robert J.; Connolly, Ryan; Holmes, Justin; Kostinski, Alexander B.

    2012-06-01

    Data from four Fermi-detected gamma-ray bursts (GRBs) are used to set limits on spectral dispersion of electromagnetic radiation across the Universe. The analysis focuses on photons recorded above 1 GeV for Fermi-detected GRB 080916C, GRB 090510A, GRB 090902B, and GRB 090926A because these high-energy photons yield the tightest bounds on light dispersion. It is shown that significant photon bunches in GRB 090510A, possibly classic GRB pulses, are remarkably brief, an order of magnitude shorter in duration than any previously claimed temporal feature in this energy range. Although conceivably a>3σ fluctuation, when taken at face value, these pulses lead to an order of magnitude tightening of prior limits on photon dispersion. Bound of Δc/c<6.94×10-21 is thus obtained. Given generic dispersion relations where the time delay is proportional to the photon energy to the first or second power, the most stringent limits on the dispersion strengths were k1<1.61×10-5secGpc-1GeV-1 and k2<3.57×10-7secGpc-1GeV-2, respectively. Such limits constrain dispersive effects created, for example, by the spacetime foam of quantum gravity. In the context of quantum gravity, our bounds set M1c2 greater than 525 times the Planck mass, suggesting that spacetime is smooth at energies near and slightly above the Planck mass.

  18. Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by the Interplanetary Network

    NASA Technical Reports Server (NTRS)

    Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Acernese, F.; Blackbum, L.; Camp, J. B.; Gehrels, N.; Graff, P. B.; Slutsky, J.; Cline, T.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Affeldt, C.; Agathos, M.; Aggarwal, N.; Aguiar, O. D.; Ajith, P.; Alemic, A.; Allen, B.; Allocca, A.

    2014-01-01

    We present the results of a search for gravitational waves associated with 223 gamma ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(exp-2) solar mass c(exp 2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.

  19. Recent Developments: The Gamma Ray Imager/Polarimeter for Solar Flares (GRIPS) Imaging and Detector systems

    NASA Astrophysics Data System (ADS)

    Duncan, Nicole; Shih, A. Y.; Hurford, G. J.; Saint-Hilaire, P.; Bain, H.; Zoglauer, A.; Lin, R. P.; Boggs, S. E.

    2013-07-01

    In two of the best-observed flares of the last cycle, the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) satellite found the centroids of ion and relativistic electron emission to have a significant displacement. This result is surprising; co-spatially accelerated ions and electrons are thought to be transported along the same field lines, implying they would enter the chromosphere together and have similar emission locations. The Gamma-Ray Imager/Polarimeter for Solar Flares (GRIPS) balloon instrument will investigate particle transport in solar flares by providing enhanced imaging, spectroscopy and polarimetry of gamma/HXR flare emission (20keV - 10MeV). GRIPS’ key technological improvements over the solar state of the art in HXR/gamma ray energies (RHESSI) include three-dimensional position-sensitive germanium detectors (3D-GeDs) and a single-grid modulating collimator, the multi-pitch rotating modulator (MPRM). The 3D-GeDs allow GRIPS to Compton track energy deposition within the crystal. This capability (1) enables the MPRM design by acting as a second modulation grid, (2) provides significant background rejection and (3) makes solar polarization measurements possible. The MPRM imager provides quasi-continuous resolution from 12.5 - 162 arcsecs with 2x the throughput of a dual grid collimator system like RHESSI. This spatial resolution can resolve the separate footpoints of many flare sizes. In comparison, RHESSI images with a minimum of 35 arcsecs for gamma-rays, making these footpoints resolvable in only the largest flares. Here, we present the intial calibration of GRIPS’ 3D-GED detectors using laboratory radioactive sources. We evaluate charge sharing between adjacent strips, the detection of coincidences and preliminary depth measurements. The detectors have been shown to have a linear response and resolve line emission. The MPRM modulation grid is constructed and we present initial results from calibration. GRIPS is scheduled for a

  20. Design, calibration, and application of an airborne gamma spectrometer system in Switzerland

    SciTech Connect

    Schwarz, G.F.; Rybach, L.; Klingele, E.E.

    1997-09-01

    Airborne radiometric surveys are finding increasingly wider application in environmental mapping and monitoring. They are the most efficient tool to delimit surface contamination and to locate lost radioactive sources. To secure radiometric capability in survey and emergency situations, a new sensitive airborne system has been built that includes an airborne spectrometer with 256 channels and a sodium iodide detector with a total volume of 16.8 liters. A rack-mounted PC with memory cards is used for data acquisition, with a GPS satellite navigation system for positioning. The system was calibrated with point sources using a mathematical correction to take into account the effects of gamma-ray scattering in the ground and in the atmosphere. The calibration was complemented by high precision ground gamma spectrometry and laboratory measurements on rock samples. In Switzerland, two major research programs make use of the capabilities of airborne radiometric measurements. The first one concerns nuclear power-plant monitoring. The five Swiss nuclear installations (four power plants and one research facility) and the surrounding regions of each site are surveyed annually. The project goal is to monitor the dose-rate distribution and to provide a documented baseline database. The measurements show that all sites (with the exception of the Goesgen power plant) can be identified clearly on the maps. No artificial radioactivity that could not be explained by the Chernobyl release or earlier nuclear weapons tests was detected outside of the fenced sites of the nuclear installations. The second program aims at a better evaluation of the natural radiation level in Switzerland. The survey focused on the crystalline rocks of the Central Massifs of the Swiss Alps because of their relatively high natural radioactivity and lithological variability.

  1. 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.

  2. Modeling And Detecting Anomalies In Scada Systems

    NASA Astrophysics Data System (ADS)

    Svendsen, Nils; Wolthusen, Stephen

    The detection of attacks and intrusions based on anomalies is hampered by the limits of specificity underlying the detection techniques. However, in the case of many critical infrastructure systems, domain-specific knowledge and models can impose constraints that potentially reduce error rates. At the same time, attackers can use their knowledge of system behavior to mask their manipulations, causing adverse effects to observed only after a significant period of time. This paper describes elementary statistical techniques that can be applied to detect anomalies in critical infrastructure networks. A SCADA system employed in liquefied natural gas (LNG) production is used as a case study.

  3. Inertial navigation sensor integrated obstacle detection system

    NASA Technical Reports Server (NTRS)

    Bhanu, Bir (Inventor); Roberts, Barry A. (Inventor)

    1992-01-01

    A system that incorporates inertial sensor information into optical flow computations to detect obstacles and to provide alternative navigational paths free from obstacles. The system is a maximally passive obstacle detection system that makes selective use of an active sensor. The active detection typically utilizes a laser. Passive sensor suite includes binocular stereo, motion stereo and variable fields-of-view. Optical flow computations involve extraction, derotation and matching of interest points from sequential frames of imagery, for range interpolation of the sensed scene, which in turn provides obstacle information for purposes of safe navigation.

  4. Voice activity detection for speaker verification systems

    NASA Astrophysics Data System (ADS)

    Borowski, Filip

    2008-01-01

    Complex algorithm for speech activity detection was presented in this article. It is based on speech enhancement, features extraction and final detection algorithm. The first one was published in ETSI standard as a module of "Advanced front-end feature extraction algorithm" in distributed speech recognition system. It consists of two main parts, noise estimatiom and Wiener filtering. For the final detection modified linear prediction coefficients and spectral entropy features are extracted form denoised signal.

  5. Driver fatigue detection system based on DSP

    NASA Astrophysics Data System (ADS)

    Wang, Qian; Yu, Fu liang; Song, Lixin

    2012-01-01

    To detect driver fatigue states effectively and in real time, a driver fatigue detection system was built, which take ICETEK-DM6347 module as system core, near-infrared LED as light source, and CCD camera as picture gathering device. An improved PER-NORFACE detection method combined several simple and efficient image processing algorithms was proposed, which based on principle of PERCLOS method and take the human face location as the main detection target. To ensure the ability of real-time processing, the algorithms on the DM6437 DaVinci processor were optimized. Experiments show that the system could complete the driver fatigue states detection accurately and in real time.

  6. Development of a high resolution gamma camera system using finely grooved GAGG scintillator

    NASA Astrophysics Data System (ADS)

    Yamamoto, Seiichi; Kataoka, Jun; Oshima, Tsubasa; Ogata, Yoshimune; Watabe, Tadashi; Ikeda, Hayato; Kanai, Yasukazu; Hatazawa, Jun

    2016-06-01

    High resolution gamma cameras require small pixel scintillator blocks with high light output. However, manufacturing a small pixel scintillator block is difficult when the pixel size becomes small. To solve this limitation, we developed a high resolution gamma camera system using a finely grooved Ce-doped Gd3Al2Ga3O12 (GAGG) plate. Our gamma camera's detector consists of a 1-mm-thick finely grooved GAGG plate that is optically coupled to a 1-in. position sensitive photomultiplier tube (PSPMT). The grooved GAGG plate has 0.2×0.2 mm pixels with 0.05-mm wide slits (between the pixels) that were manufactured using a dicing saw. We used a Hamamatsu PSPMT with a 1-in. square high quantum efficiency (HQE) PSPMT (R8900-100-C12). The energy resolution for the Co-57 gamma photons (122 keV) was 18.5% FWHM. The intrinsic spatial resolution was estimated to be 0.7-mm FWHM. With a 0.5-mm diameter pinhole collimator mounted to its front, we achieved a high resolution, small field-of-view gamma camera. The system spatial resolution for the Co-57 gamma photons was 1.0-mm FWHM, and the sensitivity was 0.0025%, 10 mm from the collimator surface. The Tc-99m HMDP administered mouse images showed the fine structures of the mouse body's parts. Our developed high resolution small pixel GAGG gamma camera is promising for such small animal imaging.

  7. Spectral catalogue of bright gamma-ray bursts detected with the BeppoSAX/GRBM

    NASA Astrophysics Data System (ADS)

    Guidorzi, C.; Lacapra, M.; Frontera, F.; Montanari, E.; Amati, L.; Calura, F.; Nicastro, L.; Orlandini, M.

    2011-02-01

    Context. The emission process responsible for the so-called "prompt" emission of gamma-ray bursts is still unknown. A number of empirical models fitting the typical spectrum still lack a satisfactory interpretation. A few GRB spectral catalogues derived from past and present experiments are known in the literature and allow to tackle the issue of spectral properties of gamma-ray bursts on a statistical ground. Aims: We extracted and studied the time-integrated photon spectra of the 200 brightest GRBs observed with the Gamma-Ray Burst Monitor which flew aboard the BeppoSAX mission (1996-2002) to provide an independent statistical characterisation of GRB spectra. Methods: The spectra have a time-resolution of 128 s and consist of 240 energy channels covering the 40-700 keV energy band. The 200 brightest GRBs were selected from the complete catalogue of 1082 GRBs detected with the GRBM (Frontera et al. 2009), whose products are publicly available and can be browsed/retrieved using a dedicated web interface. The spectra were fit with three models: a simple power law, a cut-off power law or a Band model. We derived the sample distributions of the best-fitting spectral parameters and investigated possible correlations between them. For a few, typically very long GRBs, we also provide a loose (128-s) time-resolved spectroscopic analysis. Results: The typical photon spectrum of a bright GRB consists of a low-energy index around 1.0 and a peak energy of the ν F_ν spectrum Ep ≃ 240 keV in agreement with previous results on a sample of bright CGRO/BATSE bursts. Spectra of ~ 35% of GRBs can be fit with a power law with a photon index around 2, indicative of peak energies either close to or outside the GRBM energy boundaries. We confirm the correlation between Ep and fluence, in agreement with previous results, with a logarithmic dispersion of 0.13 around the power law with index 0.21 ± 0.06. This is shallower than its analogous in the GRB rest-frame, the Amati relation

  8. Feasibility on the spectrometric determination of the individual dose rate for detected gamma nuclides using the dose rate spectroscopy

    NASA Astrophysics Data System (ADS)

    Ji, Young-Yong; Chung, Kun Ho; Lee, Wanno; Park, Doo-Won; Kang, Mun-Ja

    2014-04-01

    A spectrometric determination of the dose rate using a detector is a very useful method to identify the contribution of artificial nuclides. In addition, the individual dose rate for detected gamma nuclides from the radioactive materials as well as the environment can give further information such as the in-situ measurement because of the direct relation between the individual dose rate and the activity of a nuclide. In this study, the calculation method for the individual dose rate for detected gamma nuclides was suggested by introducing the concept of the dose rate spectroscopy and the peak-to-total ratio in the energy spectrum for the dose rate, which means just a form of multiplied counts and the value of a G-factor in the spectrum. In addition, the validity of the suggested method for the individual dose rate was experimentally verified through a comparison of the calculation results on the energy spectra for several conditions of the standard source.

  9. A virtual prototype for an explosives detection system

    SciTech Connect

    Seed, T.; Berman, B.L.; Zahrt, J.D.

    1993-10-01

    The development of the resonance-absorption based explosives detection system (EDS), as initially planned, involved the parallel development of a high-current proton accelerator (with a long development time) and the other detection subsystems. The design approach for the latter was to develop a capability for computer modeling the essential processes of each subsystem, benchmark these models by experiment, and link the models, i.e., creating a virtual prototype, to explore the effect of subsystem design changes on the EDS system performance. Additionally, when the EDS prototype system was completed, the linked models would be used to investigate further trade-offs in defining an airport system. Most of the necessary subsystem modeling was completed and used in subsystem design. Linking of all of the subsystems was accomplished to some degree or another. There are many physical and mathematical processes that take place between the acceleration of the proton beam and the final display of the reconstructed image. Figure 1 summarizes these processes and indicates which code was used to model each particular process. Section II reports on the modeling of the proton beam incident on a {sup 13}C target. The gamma-ray output is the desired output from this phase of modeling. Section III describes the tools used to investigate the transport of the gamma-rays through computer simulated phantoms (suitcases). Two different codes were used in this investigation: a Monte Carlo photon transport code and a ray tracing code. One benchmark between these codes was accomplished. Section IV is concerned with the model calculations performed on single detectors. The calculations again were performed with a Monte Carlo transport code. The reconstruction code, used throughout in the simulations and as the workhorse in the analysis of the real experiments. The authors conclude, in Section VII, with the assessment of the simulation/virtual prototyping of the real experiment.

  10. Multisensor cargo bay fire detection system

    NASA Astrophysics Data System (ADS)

    Snyder, Brian L.; Anderson, Kaare J.; Renken, Christopher H.; Socha, David M.; Miller, Mark S.

    2004-08-01

    Current aircraft cargo bay fire detection systems are generally based on smoke detection. Smoke detectors in modern aircraft are predominately photoelectric particle detectors that reliably detect smoke, but also detect dust, fog, and most other small particles. False alarms caused by these contaminants can be very costly to the airlines because they can cause flights to be diverted needlessly. To minimize these expenses, a new approach to cargo bay fire detection is needed. This paper describes a novel fire detection system developed by the Goodrich Advanced Sensors Technical Center. The system uses multiple sensors of different technologies to provide a way of discriminating between real fire events and false triggers. The system uses infrared imaging along with multiple, distributed chemical sensors and smoke detectors, all feeding data to a digital signal processor. The processor merges data from the chemical sensors, smoke detectors, and processed images to determine if a fire (or potential fire) is present. Decision algorithms look at all this data in real-time and make the final decision about whether a fire is present. In the paper, we present a short background of the problem we are solving, the reasons for choosing the technologies used, the design of the system, the signal processing methods and results from extensive system testing. We will also show that multiple sensing technologies are crucial to reducing false alarms in such systems.

  11. Computer systems for automatic earthquake detection

    USGS Publications Warehouse

    Stewart, S.W.

    1974-01-01

    U.S Geological Survey seismologists in Menlo park, California, are utilizing the speed, reliability, and efficiency of minicomputers to monitor seismograph stations and to automatically detect earthquakes. An earthquake detection computer system, believed to be the only one of its kind in operation, automatically reports about 90 percent of all local earthquakes recorded by a network of over 100 central California seismograph stations. The system also monitors the stations for signs of malfunction or abnormal operation. Before the automatic system was put in operation, all of the earthquakes recorded had to be detected by manually searching the records, a time-consuming process. With the automatic detection system, the stations are efficiently monitored continuously. 

  12. Gamma-ray detection efficiency of the microchannel plate installed as an ion detector in the low energy particle instrument onboard the GEOTAIL satellite

    SciTech Connect

    Tanaka, Y. T.; Yoshikawa, I.; Yoshioka, K.; Terasawa, T.; Saito, Y.; Mukai, T.

    2007-03-15

    A microchannel plate (MCP) assembly has been used as an ion detector in the low energy particle (LEP) instrument onboard the magnetospheric satellite GEOTAIL. Recently the MCP assembly has detected gamma rays emitted from an astronomical object and has been shown to provide unique information of gamma rays if they are intense enough. However, the detection efficiency for gamma rays was not measured before launch, and therefore we could not analyze the LEP data quantitatively. In this article, we report the gamma-ray detection efficiency of the MCP assembly. The measured efficiencies are 1.29%{+-}0.71% and 0.21%{+-}0.14% for normal incidence 60 and 662 keV gamma rays, respectively. The incident angle dependence is also presented. Our calibration is crucial to study high energy astrophysical phenomena by using the LEP.

  13. Experimental approaches for the development of gamma spectroscopy well logging system

    SciTech Connect

    Shin, Jehyun; Hwang, Seho; Kim, Jongman; Won, Byeongho

    2015-03-10

    This article discusses experimental approaches for the development of gamma spectroscopy well logging system. Considering the size of borehole sonde, we customize 2 x 2 inches inorganic scintillators and the system including high voltage, preamplifier, amplifier and multichannel analyzer (MCA). The calibration chart is made by test using standard radioactive sources so that the measured count rates are expressed by energy spectrum. Optimum high-voltage supplies and the measurement parameters of each detector are set up by experimental investigation. Also, the responses of scintillation detectors have been examined by analysis according to the distance between source and detector. Because gamma spectroscopy well logging needs broad spectrum, high sensitivity and resolution, the energy resolution and sensitivity as a function of gamma ray energy are investigated by analyzing the gamma ray activities of the radioactive sources.

  14. RADIATION DETECTING AND TELEMETERING SYSTEM

    DOEpatents

    Richards, H.K.

    1959-12-15

    A system is presented for measuring ionizing radiation at several remote stations and transmitting the measured information by radio to a central station. At each remote station a signal proportioned to the counting rate is applied across an electrical condenser made of ferroelectric material. The voltage across the condenser will vary as a function of the incident radiation and the capacitance of the condenser will vary accordingly. This change in capacitance is used to change the frequency of a crystalcontrolled oscillator. The output of the oscillator is coupled to an antenna for transmitting a signal proportional to the incident radiation.

  15. An alpha–gamma coincidence spectrometer based on the Photon–Electron Rejecting Alpha Liquid Scintillation (PERALS®) system

    DOE PAGESBeta

    Cadieux, J. R.; Fugate, G. A.; King, III, G. S.

    2015-02-07

    Here, an alpha–gamma coincidence spectrometer has been developed for the measurement of selected actinide isotopes in the presence of high beta/gamma fields. The system is based on a PERALS® liquid scintillation counter for beta/alpha discrimination and was successfully tested with both high purity germanium and bismuth germanate, gamma-ray detectors using conventional analog electronics.

  16. Multispectral imaging system for contaminant detection

    NASA Technical Reports Server (NTRS)

    Poole, Gavin H. (Inventor)

    2003-01-01

    An automated inspection system for detecting digestive contaminants on food items as they are being processed for consumption includes a conveyor for transporting the food items, a light sealed enclosure which surrounds a portion of the conveyor, with a light source and a multispectral or hyperspectral digital imaging camera disposed within the enclosure. Operation of the conveyor, light source and camera are controlled by a central computer unit. Light reflected by the food items within the enclosure is detected in predetermined wavelength bands, and detected intensity values are analyzed to detect the presence of digestive contamination.

  17. Detecting data anomalies methods in distributed systems

    NASA Astrophysics Data System (ADS)

    Mosiej, Lukasz

    2009-06-01

    Distributed systems became most popular systems in big companies. Nowadays many telecommunications companies want to hold large volumes of data about all customers. Obviously, those data cannot be stored in single database because of many technical difficulties, such as data access efficiency, security reasons, etc. On the other hand there is no need to hold all data in one place, because companies already have dedicated systems to perform specific tasks. In the distributed systems there is a redundancy of data and each system holds only interesting data in appropriate form. Data updated in one system should be also updated in the rest of systems, which hold that data. There are technical problems to update those data in all systems in transactional way. This article is about data anomalies in distributed systems. Avail data anomalies detection methods are shown. Furthermore, a new initial concept of new data anomalies detection methods is described on the last section.

  18. Application of a Multidimensional Wavelet Denoising Algorithm for the Detection and Characterization of Astrophysical Sources of Gamma Rays

    SciTech Connect

    Digel, S.W.; Zhang, B.; Chiang, J.; Fadili, J.M.; Starck, J.-L.; /Saclay /Stanford U., Statistics Dept.

    2005-12-02

    Zhang, Fadili, & Starck have recently developed a denoising procedure for Poisson data that offers advantages over other methods of intensity estimation in multiple dimensions. Their procedure, which is nonparametric, is based on thresholding wavelet coefficients. The restoration algorithm applied after thresholding provides good conservation of source flux. We present an investigation of the procedure of Zhang et al. for the detection and characterization of astrophysical sources of high-energy gamma rays, using realistic simulated observations with the Large Area Telescope (LAT). The LAT is to be launched in late 2007 on the Gamma-ray Large Area Space Telescope mission. Source detection in the LAT data is complicated by the low fluxes of point sources relative to the diffuse celestial background, the limited angular resolution, and the tremendous variation of that resolution with energy (from tens of degrees at {approx}30 MeV to 0.1{sup o} at 10 GeV). The algorithm is very fast relative to traditional likelihood model fitting, and permits immediate estimation of spectral properties. Astrophysical sources of gamma rays, especially active galaxies, are typically quite variable, and our current work may lead to a reliable method to quickly characterize the flaring properties of newly-detected sources.

  19. Structural shielding design for a gamma ray stereotactic body radiotherapy system.

    PubMed

    Xie, Xiangdong; Yang, Guoshan; Zhou, Hongmei; Qu, Decheng

    2006-09-01

    An OUR-QGD gamma ray stereotactic body radiotherapy system (body knife), made in China, is described. According to its structure and the principle of gamma radiation revolved on a focus, the energy distribution of scattered radiation in its treatment room is calculated. The structural shielding of the wall, roof, and door for a certain treatment room is calculated according to the local radiation protection law. PMID:16926472

  20. Nanotechnology-Based Systems for Nuclear Radiation and Chemicl Detection

    SciTech Connect

    Kody Varahramyan; Pedro Derosa; Chester Wilson

    2006-10-11

    This main objectives of this effort are the development and prototyping of a small. sensitive, and low-cost multi-channel nanoparticle scintillation microdevice with integrated waveguides for alpha, beta, gamma, and neutron detection. This research effort has integrated experiments and simulation to determine the combination of process-specific materials for the achievement optimum detection conditions.

  1. LuAlO3: A high density, high speed scintillator for gamma detection

    NASA Astrophysics Data System (ADS)

    Moses, W. W.; Derenzo, S. E.; Fyodorov, A.; Korzhik, M.; Gektin, A.; Minkov, B.; Aslanov, V.

    1994-11-01

    We present measurements of the scintillation properties cerium doped lutetium aluminum perovskite, LuAlO3:Ce, new dense ((rho)=8.34 g/cm(sup 3)) inorganic scintillator. This material has a 511 keV interaction length and photoelectric fraction 1.1 cm and 32% respectively, which are well suited to gamma ray detection. In powdered form with 0.5% cerium concentration, the scintillation light output is estimated to be 9,600 photons/MeV of deposited energy, the emission spectrum is a single peak centered at 390 nm, and the fluorescence lifetime is described by the sum of 3 exponential terms, with 60% of the light being emitted with a 11 ns decay time, 26% with a 28 ns decay time, and 13% with a 835 ns decay time. Single crystals contaminated with =10% lutetium aluminum garnet (Lu3Al5Ol2) have significantly altered scintillation properties. The light output is 26,000 photons/MeV (3.2 times that of BGO), but the decay time increases significantly (1% of the light is emitted with a 10 ns decay time, 15% with a 245 ns decay time, and 85% with a 2010 ns decay time) and the emission spectrum is dominated by a peak centered at 315 nm with a secondary peak centered at 500 rum. The short decay lifetime, high density, and reasonable light output of LuAlO3:Ce (the perovskite phase) suggest that it is useful for applications where high counting rates, good stopping power, good energy resolution, and fast timing are important. However, it is necessary to grow single crystals that are uncontaminated by the garnet phase to realize these properties.

  2. LuAlO{sub 3}: A high density, high speed scintillator for gamma detection

    SciTech Connect

    Moses, W.W.; Derenzo, S.E.; Fyodorov, A.; Korzhik, M.; Gektin, A.; Minkov, B.; Aslanov, V.

    1994-11-01

    We present measurements of the scintillation properties cerium doped lutetium aluminum perovskite, LuAlO{sub 3}:C, new dense ({rho}=8.34 g/cm{sup 3}) inorganic scintillator. This material has a 511 keV interaction length and photoelectric fraction 1.1 cm and 32% respectively, which are well suited to gamma ray detection. In powdered form with 0.5% cerium concentration, the scintillation light output is estimated to be 9,600 photons/MeV of deposited energy, the emission spectrum is a single peak centered at 390 nm, and the fluorescence lifetime is described by the sum of 3 exponential terms, with 60% of the light being emitted with a 11 ns decay time, 26% with a 28 ns decay time, and 13% with a 835 ns decay time. Single crystals contaminated with =10% lutetium aluminum garnet (Lu{sub 3}Al{sub 5}O{sub l2}) have significantly altered scintillation properties. The light output is 26,000 photons/MeV (3.2 times that of BGO), but the decay time increases significantly (1% of the light is emitted with a 10 ns decay time, 15% with a 245 ns decay time, and 85% with a 2010 ns decay time) and the emission spectrum is dominated by a peak centered at 315 nm with a secondary peak centered at 500 rum. The short decay lifetime, high density, and reasonable light output of LuAlO{sub 3}:C (the perovskite phase) suggest that it is useful for applications where high counting rates, good stopping power, good energy resolution, and fast timing are important. However, it is necessary to grow single crystals that are uncontaminated by the garnet phase to realize these properties.

  3. Linac based photofission inspection system employing novel detection concepts

    NASA Astrophysics Data System (ADS)

    Stevenson, John; Gozani, Tsahi; Elsalim, Mashal; Condron, Cathie; Brown, Craig

    2011-10-01

    Rapiscan Systems is developing a LINAC based cargo inspection system for detection of special nuclear material (SNM) in cargo containers. The system, called Photofission Based Alarm Resolution (PBAR) is being developed under a DHD/DNDO Advanced Technology Demonstration (ATD) program. The PBAR system is based on the Rapiscan Eagle P9000 X-ray system, which is a portal system with a commercial 9 MeV LINAC X-ray source. For the purposes of the DNDO ATD program, a conveyor system was installed in the portal to allow scanning and precise positioning of 20 ft ISO cargo containers. The system uses a two step inspection process. In the first step, the basic scan, the container is quickly and completely inspected using two independent radiography arrays: the conventional primary array with high spatial resolution and a lower resolution spectroscopic array employing the novel Z-Spec method. The primary array uses cadmium tungstate (CdWO 4) detectors with conventional current mode readouts using photodiodes. The Z-Spec array uses small plastic scintillators capable of performing very fast (up to 10 8 cps) gamma-ray spectroscopy. The two radiography arrays are used to locate high-Z objects in the image such as lead, tungsten, uranium, which could be potential shielding materials as well as SNM itself. In the current system, the Z-Spec works by measuring the energy spectrum of transmitted X-rays. For high-Z materials the higher end of the energy spectrum is more attenuated than for low-Z materials and thus has a lower mean energy and a narrower width than low- and medium-Z materials. The second step in the inspection process is the direct scan or alarm clearing scan. In this step, areas of the container image, which were identified as high Z, are re-inspected. This is done by precisely repositioning the container to the location of the high-Z object and performing a stationary irradiation of the area with X-ray beam. Since there are a large number of photons in the 9 MV

  4. Fermi LAT Pulsed Detection of PSR J0737-3039A in the Double Pulsar System

    NASA Technical Reports Server (NTRS)

    Guillemot, L.; Kramer, M.; Johnson, T. J.; Craig, H. A.; Romani, R. W.; Venter, C.; Harding, A. K.; Ferdman, R. D.; Stairs, I. H.; Kerr, M.

    2013-01-01

    We report the Fermi Large Area Telescope discovery of gamma-ray pulsations from the 22.7 ms pulsar A in the double pulsar system J0737-3039A/B. This is the first mildly recycled millisecond pulsar (MSP) detected in the GeV domain. The 2.7 s companion object PSR J0737-3039B is not detected in gamma rays. PSR J0737-3039A is a faint gamma-ray emitter, so that its spectral properties are only weakly constrained; however, its measured efficiency is typical of other MSPs. The two peaks of the gamma-ray light curve are separated by roughly half a rotation and are well offset from the radio and X-ray emission, suggesting that the GeV radiation originates in a distinct part of the magnetosphere from the other types of emission. From the modeling of the radio and the gamma-ray emission profiles and the analysis of radio polarization data, we constrain the magnetic inclination alpha and the viewing angle zeta to be close to 90 deg., which is consistent with independent studies of the radio emission from PSR J0737-3039A. A small misalignment angle between the pulsar's spin axis and the system's orbital axis is therefore favored, supporting the hypothesis that pulsar B was formed in a nearly symmetric supernova explosion as has been discussed in the literature already.

  5. FERMI LAT PULSED DETECTION OF PSR J0737-3039A IN THE DOUBLE PULSAR SYSTEM

    SciTech Connect

    Guillemot, L.; Kramer, M.; Johnson, T. J.; Craig, H. A.; Romani, R. W.; Kerr, M.; Venter, C.; Harding, A. K.; Ferdman, R. D.; Stairs, I. H.

    2013-05-10

    We report the Fermi Large Area Telescope discovery of {gamma}-ray pulsations from the 22.7 ms pulsar A in the double pulsar system J0737-3039A/B. This is the first mildly recycled millisecond pulsar (MSP) detected in the GeV domain. The 2.7 s companion object PSR J0737-3039B is not detected in {gamma} rays. PSR J0737-3039A is a faint {gamma}-ray emitter, so that its spectral properties are only weakly constrained; however, its measured efficiency is typical of other MSPs. The two peaks of the {gamma}-ray light curve are separated by roughly half a rotation and are well offset from the radio and X-ray emission, suggesting that the GeV radiation originates in a distinct part of the magnetosphere from the other types of emission. From the modeling of the radio and the {gamma}-ray emission profiles and the analysis of radio polarization data, we constrain the magnetic inclination {alpha} and the viewing angle {zeta} to be close to 90 Degree-Sign , which is consistent with independent studies of the radio emission from PSR J0737-3039A. A small misalignment angle between the pulsar's spin axis and the system's orbital axis is therefore favored, supporting the hypothesis that pulsar B was formed in a nearly symmetric supernova explosion as has been discussed in the literature already.

  6. Automated Hydrogen Gas Leak Detection System

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Gencorp Aerojet Automated Hydrogen Gas Leak Detection System was developed through the cooperation of industry, academia, and the Government. Although the original purpose of the system was to detect leaks in the main engine of the space shuttle while on the launch pad, it also has significant commercial potential in applications for which there are no existing commercial systems. With high sensitivity, the system can detect hydrogen leaks at low concentrations in inert environments. The sensors are integrated with hardware and software to form a complete system. Several of these systems have already been purchased for use on the Ford Motor Company assembly line for natural gas vehicles. This system to detect trace hydrogen gas leaks from pressurized systems consists of a microprocessor-based control unit that operates a network of sensors. The sensors can be deployed around pipes, connectors, flanges, and tanks of pressurized systems where leaks may occur. The control unit monitors the sensors and provides the operator with a visual representation of the magnitude and locations of the leak as a function of time. The system can be customized to fit the user's needs; for example, it can monitor and display the condition of the flanges and fittings associated with the tank of a natural gas vehicle.

  7. Flat Surface Damage Detection System (FSDDS)

    NASA Technical Reports Server (NTRS)

    Williams, Martha; Lewis, Mark; Gibson, Tracy; Lane, John; Medelius, Pedro; Snyder, Sarah; Ciarlariello, Dan; Parks, Steve; Carrejo, Danny; Rojdev, Kristina

    2013-01-01

    The Flat Surface Damage Detection system (FSDDS} is a sensory system that is capable of detecting impact damages to surfaces utilizing a novel sensor system. This system will provide the ability to monitor the integrity of an inflatable habitat during in situ system health monitoring. The system consists of three main custom designed subsystems: the multi-layer sensing panel, the embedded monitoring system, and the graphical user interface (GUI). The GUI LABVIEW software uses a custom developed damage detection algorithm to determine the damage location based on the sequence of broken sensing lines. It estimates the damage size, the maximum depth, and plots the damage location on a graph. Successfully demonstrated as a stand alone technology during 2011 D-RATS. Software modification also allowed for communication with HDU avionics crew display which was demonstrated remotely (KSC to JSC} during 2012 integration testing. Integrated FSDDS system and stand alone multi-panel systems were demonstrated remotely and at JSC, Mission Operations Test using Space Network Research Federation (SNRF} network in 2012. FY13, FSDDS multi-panel integration with JSC and SNRF network Technology can allow for integration with other complementary damage detection systems.

  8. Detection probability of EBPSK-MODEM system

    NASA Astrophysics Data System (ADS)

    Yao, Yu; Wu, Lenan

    2016-07-01

    Since the impacting filter-based receiver is able to transform phase modulation into amplitude peak, a simple threshold decision can detect the Extend-Binary Phase Shift Keying (EBPSK) modulated ranging signal in noise environment. In this paper, an analysis of the EBPSK-MODEM system output gives the probability density function for EBPSK modulated signals plus noise. The equation of detection probability (pd) for fluctuating and non-fluctuating targets has been deduced. Also, a comparison of the pd for the EBPSK-MODEM system and pulse radar receiver is made, and some results are plotted. Moreover, the probability curves of such system with several modulation parameters are analysed. When modulation parameter is not smaller than 6, the detection performance of EBPSK-MODEM system is more excellent than traditional radar system. In addition to theoretical considerations, computer simulations are provided for illustrating the performance.

  9. Simulation and modeling for the stand-off radiation detection system (SORDS) using GEANT4

    SciTech Connect

    Hoover, Andrew S; Wallace, Mark; Galassi, Mark; Mocko, Michal; Palmer, David; Schultz, Larry; Tornga, Shawn

    2009-01-01

    A Stand-Off Radiation Detection System (SORDS) is being developed through a joint effort by Raytheon, Los Alamos National Laboratory, Bubble Technology Industries, Radiation Monitoring Devices, and the Massachusetts Institute of Technology, for the Domestic Nuclear Detection Office (DNDO). The system is a mobile truck-based platform performing detection, imaging, and spectroscopic identification of gamma-ray sources. A Tri-Modal Imaging (TMI) approach combines active-mask coded aperture imaging, Compton imaging, and shadow imaging techniques. Monte Carlo simulation and modeling using the GEANT4 toolkit was used to generate realistic data for the development of imaging algorithms and associated software code.

  10. Detection of 511 keV positron annihilation radiation from the galactic center direction. [gamma ray astronomy

    NASA Technical Reports Server (NTRS)

    Leventhal, M.; Maccallum, C. J.; Stang, P. D.

    1978-01-01

    A balloon-borne gamma ray telescope with an approximately 130 cu cm high purity germanium detector was flown over Australia to detect sharp spectral features from the galactic center direction. A 511 keV positron annihilation line was observed at a flux level of (1.21 plus or minus 0.22) x (10/cu cm) photons/sec/sp cm. Suggestive evidence for the detection of the three-photon positronium continuum is presented. The possible origin of the positrons is discussed.

  11. Note on the detection of high energy primary cosmic gamma rays by air shower observation

    NASA Technical Reports Server (NTRS)

    Kasahara, K.; Torii, S.; Yuda, T.

    1985-01-01

    A mountain altitude experiment is planned at Mt. Norikura in Japan to search for point sources of astrophysical high-energy gamma rays in the 10 to the 15th power eV range. The advantages of mountain level observation of IR showers is stressed, especially in the case of high-energy gamma primaries from Cygnus X3 and other similar point sources.

  12. The time-of-flight system on the Goddard medium energy gamma-ray telescope

    NASA Technical Reports Server (NTRS)

    Ross, R. W.; Chesney, J. R.

    1979-01-01

    A scintillation counter time of flight system, incorporated into the Goddard 50 cm by 50 cm spark chamber gamma ray telescope is described. The system, which utilizes constant fractions timing and particle position compensation and digitizes up to 10 ns time differences to six bit accuracy in less than 500 ns is analyzed. The performance of this system during balloon flight is discussed.

  13. Analytical computation of prompt gamma ray emission and detection for proton range verification.

    PubMed

    Sterpin, E; Janssens, G; Smeets, J; Vander Stappen, François; Prieels, D; Priegnitz, Marlen; Perali, Irene; Vynckier, S

    2015-06-21

    A prompt gamma (PG) slit camera prototype recently demonstrated that Bragg Peak position in a clinical proton scanned beam could be measured with 1-2 mm accuracy by comparing an expected PG detection profile to a measured one. The computation of the expected PG detection profile in the context of a clinical framework is challenging but must be solved before clinical implementation. Obviously, Monte Carlo methods (MC) can simulate the expected PG profile but at prohibitively long calculation times. We implemented a much faster method that is based on analytical processing of precomputed MC data that would allow practical evaluation of this range monitoring approach in clinical conditions. Reference PG emission profiles were generated with MC simulations (PENH) in targets consisting of either (12)C, (14)N, (16)O, (31)P or (40)Ca, with 10% of (1)H. In a given geometry, the local PG emission can then be derived by adding the contribution of each element, according to the local energy of the proton obtained by continuous slowing down approximation and the local composition. The actual incident spot size is taken into account using an optical model fitted to measurements and by super sampling the spot with several rays (up to 113). PG transport in the patient/camera geometries and the detector response are modelled by convolving the PG production profile with a transfer function. The latter is interpolated from a database of transfer functions fitted to MC data (PENELOPE) generated for a photon source in a cylindrical phantom with various radiuses and a camera placed at various positions. As a benchmark, the analytical model was compared to MC and experiments in homogeneous and heterogeneous phantoms. Comparisons with MC were also performed in a thoracic CT. For all cases, the analytical model reproduced the prediction of the position of the Bragg peak computed with MC within 1 mm for the camera in nominal configuration. When compared to measurements, the shape of the

  14. Analytical computation of prompt gamma ray emission and detection for proton range verification

    NASA Astrophysics Data System (ADS)

    Sterpin, E.; Janssens, G.; Smeets, J.; Vander Stappen, François; Prieels, D.; Priegnitz, Marlen; Perali, Irene; Vynckier, S.

    2015-06-01

    A prompt gamma (PG) slit camera prototype recently demonstrated that Bragg Peak position in a clinical proton scanned beam could be measured with 1-2 mm accuracy by comparing an expected PG detection profile to a measured one. The computation of the expected PG detection profile in the context of a clinical framework is challenging but must be solved before clinical implementation. Obviously, Monte Carlo methods (MC) can simulate the expected PG profile but at prohibitively long calculation times. We implemented a much faster method that is based on analytical processing of precomputed MC data that would allow practical evaluation of this range monitoring approach in clinical conditions. Reference PG emission profiles were generated with MC simulations (PENH) in targets consisting of either 12C, 14N, 16O, 31P or 40Ca, with 10% of 1H. In a given geometry, the local PG emission can then be derived by adding the contribution of each element, according to the local energy of the proton obtained by continuous slowing down approximation and the local composition. The actual incident spot size is taken into account using an optical model fitted to measurements and by super sampling the spot with several rays (up to 113). PG transport in the patient/camera geometries and the detector response are modelled by convolving the PG production profile with a transfer function. The latter is interpolated from a database of transfer functions fitted to MC data (PENELOPE) generated for a photon source in a cylindrical phantom with various radiuses and a camera placed at various positions. As a benchmark, the analytical model was compared to MC and experiments in homogeneous and heterogeneous phantoms. Comparisons with MC were also performed in a thoracic CT. For all cases, the analytical model reproduced the prediction of the position of the Bragg peak computed with MC within 1 mm for the camera in nominal configuration. When compared to measurements, the shape of the profiles

  15. REBOCOL (Robotic Calorimetry): An automated NDA (Nondestructive assay) calorimetry and gamma isotopic system

    SciTech Connect

    Hurd, J.R.; Bonner, C.A.; Ostenak, C.A.; Phelan, P.F.; Powell, W.D.; Sheer, N.L.; Schneider, D.N.; Staley, H.C.

    1989-01-01

    ROBOCAL, which is presently being developed and tested at Los Alamos National Laboratory, is a full-scale, prototypical robotic system, for remote calorimetric and gamma-ray analysis of special nuclear materials. It integrates a fully automated, multi-drawer, vertical stacker-retriever system for staging unmeasured nuclear materials, and a fully automated gantry robot for computer-based selection and transfer of nuclear materials to calorimetric and gamma-ray measurement stations. Since ROBOCAL is designed for minimal operator intervention, a completely programmed user interface and data-base system are provided to interact with the automated mechanical and assay systems. The assay system is designed to completely integrate calorimetric and gamma-ray data acquisition and to perform state-of-the-art analyses on both homogeneous and heterogeneous distributions of nuclear materials in a wide variety of matrices. 10 refs., 10 figs., 4 tabs.

  16. Windshear detection and avoidance - Airborne systems survey

    NASA Technical Reports Server (NTRS)

    Bowles, Roland L.

    1990-01-01

    Functional requirements for airborne windshear detection and warning systems are discussed in terms of the threat posed to civil aircraft operations. A preliminary set of performance criteria for predictive windshear detection and warning systems is defined. Candidate airborne remote sensor technologies based on microwave Doppler radar, Doppler laser radar (lidar), and infrared radiometric techniques are discussed in the context of overall system requirements, and the performance of each sensor is assessed for representative microburst environments and ground clutter conditions. Preliminary simulation results demonstrate that all three sensors show potential for detecting windshear, and provide adequate warning time to allow flight crews to avoid the affected area or escape from the encounter. Radar simulation and analysis show that by using bin-to-bin automatic gain control, clutter filtering, limited detection range, and suitable antenna tilt management, windshear from wet microbursts can be accurately detected. Although a performance improvement can be obtained at higher radar frequency, the baseline X-band system also detected the presence of windshear hazard for a dry microburst. Simulation results of end-to-end performance for competing coherent lidar systems are presented.

  17. Gamma irradiation as a biological decontaminant and its effect on common fingermark detection techniques and DNA profiling.

    PubMed

    Hoile, Rebecca; Banos, Connie; Colella, Michael; Walsh, Simon J; Roux, Claude

    2010-01-01

    The use of disease-causing organisms and their toxins against the civilian population has defined bioterrorism and opened forensic science up to the challenges of processing contaminated evidence. This study sought to determine the use of gamma irradiation as an effective biological decontaminant and its effect on the recovery of latent fingermarks from both porous and nonporous items. Test items were contaminated with viable spores marked with latent prints and then decontaminated using a cobalt 60 gamma irradiator. Fingermark detection was the focus with standard methods including 1,2-indanedione, ninhydrin, diazafluoren-9-one, and physical developer used during this study. DNA recovery using 20% Chelex extraction and quantitative real-time polymerase chain reaction was also explored. Gamma irradiation proved effective as a bacterial decontaminant with D-values ranging from 458 to 500 Gy for nonporous items and 797-808 Gy for porous ones. The results demonstrated the successful recovery of latent marks and DNA establishing gamma irradiation as a viable decontamination option. PMID:20002271

  18. Stimulus generation technique for code simulation of FPGA based gamma spectroscopy system

    NASA Astrophysics Data System (ADS)

    Rahman, Nur Aira Abd; Ramli, Abdul Rahman; Lombigit, Lojius; Abdullah, Nor Arymaswati; Khalid, Mohd Ashhar Hj

    2014-02-01

    The aim of this study is to develop a software that can systematically generate stimulus required for code simulation (functional and timing) of new digital processors in gamma spectroscopy system. Software must be able to produce stimulus that emulate ADC data of charge sensitive amplifier (CSA) output signal. Signal parameters such as pulse shape, amplitude, pulse width and count rate should be adjustable while allowing options such as pulse pile-up and random pulse events. To fulfill this objective, a pulse generator software PulseGEN has been developed. The software GUI is designed to operate in two modes, Single/Pile-Up Mode and Continuous Random Mode. Its ADC module simulates real-time ADC sampling. The output can be saved as input stimulus to test various functions of digital processors such as pulse height measurements, pile-up detection and correction, as well as random pulse detection and measurement that is similar to the actual real-time measurement. PulseGEN results have been compared and verified against commercial charge sensitive amplifier with NaI detector and NIM pulser.

  19. Why Have Many of the Brightest Radio-loud Blazars Not Been Detected in Gamma-Rays by Fermi?

    NASA Astrophysics Data System (ADS)

    Lister, M. L.; Aller, M. F.; Aller, H. D.; Hovatta, T.; Max-Moerbeck, W.; Readhead, A. C. S.; Richards, J. L.; Ros, E.

    2015-09-01

    We use the complete MOJAVE 1.5 Jy sample of active galactic nuclei (AGNs) to examine the gamma-ray detection statistics of the brightest radio-loud blazars in the northern sky. We find that 23% of these AGNs were not detected above 0.1 GeV by the Fermi-LAT during the four-year 3FGL catalog period partly because of an instrumental selection effect and partly due to their lower Doppler boosting factors. Blazars with synchrotron peaks in their spectral energy distributions located below {10}13.4 Hz also tend to have high-energy peaks that lie below the 0.1 GeV threshold of the LAT, and are thus less likely to be detected by Fermi. The non-detected AGNs in the 1.5 Jy sample also have significantly lower 15 GHz radio modulation indices and apparent jet speeds, indicating that they have lower than average Doppler factors. Since the effective amount of relativistic Doppler boosting is enhanced in gamma-rays (particularly in the case of external inverse-Compton scattering), this makes them less likely to appear in the 3FGL catalog. Based on their observed properties, we have identified several bright radio-selected blazars that are strong candidates for future detection by Fermi.

  20. Detection of Illicit Drugs with the EURITRACK System

    NASA Astrophysics Data System (ADS)

    Perot, B.; Carasco, C.; Valkovic, V.; Sudac, D.; Franulovic, A.

    2009-03-01

    The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) inspection system has been developed within the 6th EU Framework Program to complement X-ray scanners in the detection of explosives and other illicit materials hidden in cargo containers. Gamma rays are produced inside the cargo materials by 14 MeV tagged neutron beams, which yields information about the chemical composition of the transported goods. In the beginning of year 2007, the EURITRACK system was implemented in the Seaport of Rijeka, Croatia, primarily to carry out a demonstration using real containers to conduct a series of detection tests. This article reports tests performed with real samples of illicit drugs hidden in a metallic cargo with an average density of 0.2 g/cm3. Heroin and cocaine have been distinguished from benign substances based on their chemical composition. Marijuana, which chemical composition is similar to benign materials, cannot be distinguished from common organic goods. However, the detection of an unexpected organic substance inside the metallic cargo indicates that a suspicious object has been hidden in the container.

  1. Force protection demining system (FPDS) detection subsystem

    NASA Astrophysics Data System (ADS)

    Zachery, Karen N.; Schultz, Gregory M.; Collins, Leslie M.

    2005-06-01

    This study describes the U.S. Army Force Protection Demining System (FPDS); a remotely-operated, multisensor platform developed for reliable detection and neutralization of both anti-tank and anti-personnel landmines. The ongoing development of the prototype multisensor detection subsystem is presented, which integrates an advanced electromagnetic pulsed-induction array and ground penetrating synthetic aperture radar array on a single standoff platform. The FPDS detection subsystem is mounted on a robotic rubber-tracked vehicle and incorporates an accurate and precise navigation/positioning module making it well suited for operation in varied and irregular terrains. Detection sensors are optimally configured to minimize interference without loss in sensitivity or performance. Mine lane test data acquired from the prototype sensors are processed to extract signal- and image-based features for automatic target recognition. Preliminary results using optimal feature and classifier selection indicate the potential of the system to achieve high probabilities of detection while minimizing false alarms. The FPDS detection software system also exploits modern multi-sensor data fusion algorithms to provide real-time detection and discrimination information to the user.

  2. EBT-P gamma-ray shielding system

    SciTech Connect

    Gohar, Y.

    1981-12-01

    An elaborate study was carried out for the coil and biological shield of the ELMO Bumpy Torus proof-of-principle (EBT-P) device. A three-dimensional scoping study for the coil shield was performed for four different shielding options to define the heat load for each component and check the compliance with the design criterion of 10 watts maximum heat per coil from the gamma ray sources. Also, a detailed biological dose survey was performed which included: (a) the dose equivalent inside and outside the building, (b) the dose equivalent from the two mazes of the machine room, and (c) the skyshine contribution to the dose equivalent.

  3. Improved readout system for multi-crystal gamma cameras

    DOEpatents

    Derenzo, S.E.

    1985-08-21

    A radioisotope camera having an array of scintillation crystals arranged in N rows and M columns and adapted to be struck by gamma-rays from a subject, a separate solid state photodetector optically coupled to each crystal, and N + M amplifiers connected to the photodetectors to distinguish the particular row and column of an activated photodetector. One of the anode or cathode leads of each photodetector is coupled to the row amplifier associated with the row containing that photodetector while the other of the two leads is coupled to the column amplifier associated with the column containing that photodetector.

  4. A system for distributed intrusion detection

    SciTech Connect

    Snapp, S.R.; Brentano, J.; Dias, G.V.; Goan, T.L.; Heberlein, L.T.; Ho, Che-Lin; Levitt, K.N.; Mukherjee, B. . Div. of Computer Science); Grance, T. ); Mansur, D.L.; Pon, K.L. ); Smaha, S.E. )

    1991-01-01

    The study of providing security in computer networks is a rapidly growing area of interest because the network is the medium over which most attacks or intrusions on computer systems are launched. One approach to solving this problem is the intrusion-detection concept, whose basic premise is that not only abandoning the existing and huge infrastructure of possibly-insecure computer and network systems is impossible, but also replacing them by totally-secure systems may not be feasible or cost effective. Previous work on intrusion-detection systems were performed on stand-alone hosts and on a broadcast local area network (LAN) environment. The focus of our present research is to extend our network intrusion-detection concept from the LAN environment to arbitarily wider areas with the network topology being arbitrary as well. The generalized distributed environment is heterogeneous, i.e., the network nodes can be hosts or servers from different vendors, or some of them could be LAN managers, like our previous work, a network security monitor (NSM), as well. The proposed architecture for this distributed intrusion-detection system consists of the following components: a host manager in each host; a LAN manager for monitoring each LAN in the system; and a central manager which is placed at a single secure location and which receives reports from various host and LAN managers to process these reports, correlate them, and detect intrusions. 11 refs., 2 figs.

  5. Effect of chromosome size on aberration levels caused by gamma radiation as detected by fluorescence in situ hybridization.

    PubMed

    Pandita, T K; Gregoire, V; Dhingra, K; Hittelman, W N

    1994-01-01

    Fluorescence in situ hybridization (FISH) is a powerful technique for detecting genomic alterations at the chromosome level. To study the effect of chromosome size on aberration formation, we used FISH to detect initial damage in individual prematurely condensed chromosomes (PCC) of gamma-irradiated G0 human cells. A linear dose response for breaks and a nonlinear dose response for exchanges was obtained using a chromosome 1-specific probe. FISH detected more chromosome 1 breaks than expected from DNA based extrapolation of Giemsa stained PCC preparations. The discrepancy in the number of breaks detected by the two techniques raised questions as to whether Giemsa staining and FISH differ in their sensitivities for detecting breaks, or is chromosome 1 uniquely sensitive to gamma-radiation. To address the question of technique sensitivity, we determined total chromosome damage by FISH using a total genomic painting probe; the results obtained from Giemsa-staining and FISH were nearly identical. To determine if chromosome 1 was uniquely sensitive, we selected four different sized chromosomes for paint probes and scored them for gamma-ray induced aberrations. In these studies the number of chromosome breaks per unit DNA increased linearly with an increase in the DNA content of the chromosomes. However, the number of exchanges per unit of DNA did not increase with an increase in chromosome size. This suggests that chromosome size may influence the levels of aberrations observed. Extrapolation from measurements of a single chromosome's damage to the whole genome requires that the relative DNA content of the measured chromosome be considered. PMID:8039428

  6. Capacitive system detects and locates fluid leaks

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Electronic monitoring system automatically detects and locates minute leaks in seams of large fluid storage tanks and pipelines covered with thermal insulation. The system uses a capacitive tape-sensing element that is adhesively bonded over seams where fluid leaks are likely to occur.

  7. Advanced Atmospheric Water Vapor DIAL Detection System

    NASA Technical Reports Server (NTRS)

    Refaat, Tamer F.; Elsayed-Ali, Hani E.; DeYoung, Russell J. (Technical Monitor)

    2000-01-01

    Measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The remote sensing Differential Absorption Lidar (DIAL) technique is a powerful method to perform such measurement from aircraft and space. This thesis describes a new advanced detection system, which incorporates major improvements regarding sensitivity and size. These improvements include a low noise advanced avalanche photodiode detector, a custom analog circuit, a 14-bit digitizer, a microcontroller for on board averaging and finally a fast computer interface. This thesis describes the design and validation of this new water vapor DIAL detection system which was integrated onto a small Printed Circuit Board (PCB) with minimal weight and power consumption. Comparing its measurements to an existing DIAL system for aerosol and water vapor profiling validated the detection system.

  8. A cable detection lidar system for helicopters

    NASA Technical Reports Server (NTRS)

    Grossmann, Benoist; Capbern, Alain; Defour, Martin; Fertala, Remi

    1992-01-01

    Helicopters in low-level flight are endangered by power lines or telephone wires, especially when flying at night and under poor visibility conditions. In order to prevent 'wire strike', Thomson has developed a lidar system consisting of a pulsed diode laser emitting in the near infrared region (lambda = 0.9 microns). The HOWARD (Helicopter Obstacle Warning and Detection) System utilizes a high repetition rate diode laser (PRE = 20 KHz) along with counter-rotating prisms for laser beam deflection with a total field of view of 30 degrees. This system was successfully field tested in 1991. HOWARD can detect one inch wires at ranges up to 200 meters. We are presently in the process of developing a flyable compact lidar system capable of detection ranges in the order of 400 meters.

  9. CMOS image sensor for detection of interferon gamma protein interaction as a point-of-care approach.

    PubMed

    Marimuthu, Mohana; Kandasamy, Karthikeyan; Ahn, Chang Geun; Sung, Gun Yong; Kim, Min-Gon; Kim, Sanghyo

    2011-09-01

    Complementary metal oxide semiconductor (CMOS)-based image sensors have received increased attention owing to the possibility of incorporating them into portable diagnostic devices. The present research examined the efficiency and sensitivity of a CMOS image sensor for the detection of antigen-antibody interactions involving interferon gamma protein without the aid of expensive instruments. The highest detection sensitivity of about 1 fg/ml primary antibody was achieved simply by a transmission mechanism. When photons are prevented from hitting the sensor surface, a reduction in digital output occurs in which the number of photons hitting the sensor surface is approximately proportional to the digital number. Nanoscale variation in substrate thickness after protein binding can be detected with high sensitivity by the CMOS image sensor. Therefore, this technique can be easily applied to smartphones or any clinical diagnostic devices for the detection of several biological entities, with high impact on the development of point-of-care applications. PMID:21773736

  10. Gamma-ray and neutron radiography as part of a pulsed fast neutron analysis inspection system

    NASA Astrophysics Data System (ADS)

    Rynes, J.; Bendahan, J.; Gozani, T.; Loveman, R.; Stevenson, J.; Bell, C.

    1999-02-01

    A gamma-ray and neutron radiography system has been developed to provide useful supplemental information for a Pulsed Fast Neutron Analysis (PFNA) cargo inspection system. PFNA uses a collimated beam of pulsed neutrons to interrogate cargoes using (n, γx) reactions. The PFNA source produces both gamma rays as well as neutrons. The transmission of both species through the cargo is measured with an array of plastic scintillators. Since the neutron and gamma-ray signals are easily separated by arrival time a separate image can be made for both species. The radiography measurement is taken simultaneously with the PFNA measurement turning PFNA into an emission and transmission imaging system, thus enhancing the PFNA radiography system.

  11. Portable LN 2 gamma-ray spectrometer system

    NASA Astrophysics Data System (ADS)

    McElhaney, S. A.; Brogle, R.; Guim, A.; Gerrish, A. M.; Lasché, G. P.; Nobel, J.; Pauly, S.

    1999-02-01

    The purpose of this program is to design and demonstrate a highly sensitive, portable spectrometer for detecting and identifying trace amounts of nuclear materials in a broad range of nonproliferation scenarios. A high-efficiency 100% n-type germanium (Ge) detector is combined with a special liquid nitrogen dewar designed to accommodate an active Compton suppression shield. The added collimation capability is required in order to be able to identify localized sources that may be obscured by background radiation. These components are complemented by the addition of a newly developed state-of-the-art multichannel analyzer (MCA) capable of 64×16 000 channel acquisition and electronic Compton suppression. The entire system fits into a watertight case that could be stored below the seat of commercial airliners. The unit has 2.74 keV resolution at 1.33 MeV, 8.5° angular resolution, low-power, >25 h full-time battery life, and operations between 35 keV< E<3 MeV.

  12. Performance degradation of QAM based inter-satellite optical communication system under gamma irradiation

    NASA Astrophysics Data System (ADS)

    Liu, Yun; Zhao, Shanghong; Gong, Zizheng; Zhao, Jing; Li, Xuan

    2016-01-01

    Main devices in quadrature amplitude modulation (QAM) based inter-satellite optical communication system were irradiated to a total dose of 20 krad with the dose rate of 5 rad/s using a Co60 radiation source. Gamma irradiation impacts on devices were analyzed and on the basis, system performance degradation was simulated. Variety of system BER along with onboard working time for different inter-satellite links was presented. In addition, some adaption methods were proposed to reduce gamma irradiation induced degradation.

  13. New readout and data-acquisition system in an electron-tracking Compton camera for MeV gamma-ray astronomy (SMILE-II)

    NASA Astrophysics Data System (ADS)

    Mizumoto, T.; Matsuoka, Y.; Mizumura, Y.; Tanimori, T.; Kubo, H.; Takada, A.; Iwaki, S.; Sawano, T.; Nakamura, K.; Komura, S.; Nakamura, S.; Kishimoto, T.; Oda, M.; Miyamoto, S.; Takemura, T.; Parker, J. D.; Tomono, D.; Sonoda, S.; Miuchi, K.; Kurosawa, S.

    2015-11-01

    For MeV gamma-ray astronomy, we have developed an electron-tracking Compton camera (ETCC) as a MeV gamma-ray telescope capable of rejecting the radiation background and attaining the high sensitivity of near 1 mCrab in space. Our ETCC comprises a gaseous time-projection chamber (TPC) with a micro pattern gas detector for tracking recoil electrons and a position-sensitive scintillation camera for detecting scattered gamma rays. After the success of a first balloon experiment in 2006 with a small ETCC (using a 10×10×15 cm3 TPC) for measuring diffuse cosmic and atmospheric sub-MeV gamma rays (Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment I; SMILE-I), a (30 cm)3 medium-sized ETCC was developed to measure MeV gamma-ray spectra from celestial sources, such as the Crab Nebula, with single-day balloon flights (SMILE-II). To achieve this goal, a 100-times-larger detection area compared with that of SMILE-I is required without changing the weight or power consumption of the detector system. In addition, the event rate is also expected to dramatically increase during observation. Here, we describe both the concept and the performance of the new data-acquisition system with this (30 cm)3 ETCC to manage 100 times more data while satisfying the severe restrictions regarding the weight and power consumption imposed by a balloon-borne observation. In particular, to improve the detection efficiency of the fine tracks in the TPC from ~10% to ~100%, we introduce a new data-handling algorithm in the TPC. Therefore, for efficient management of such large amounts of data, we developed a data-acquisition system with parallel data flow.

  14. Coal-shale interface detection system

    NASA Technical Reports Server (NTRS)

    Campbell, R. A.; Hudgins, J. L.; Morris, P. W.; Reid, H., Jr.; Zimmerman, J. E. (Inventor)

    1979-01-01

    A coal-shale interface detection system for use with coal cutting equipment consists of a reciprocating hammer on which an accelerometer is mounted to measure the impact of the hammer as it penetrates the ceiling or floor surface of a mine. A pair of reflectometers simultaneously view the same surface. The outputs of the accelerometer and reflectometers are detected and jointly registered to determine when an interface between coal and shale is being cut through.

  15. Distributed fiber optic fuel leak detection system

    NASA Astrophysics Data System (ADS)

    Mendoza, Edgar; Kempen, C.; Esterkin, Yan; Sun, Sonjian

    2013-05-01

    With the increase worldwide demand for hydrocarbon fuels and the vast development of new fuel production and delivery infrastructure installations around the world, there is a growing need for reliable fuel leak detection technologies to provide safety and reduce environmental risks. Hydrocarbon leaks (gas or liquid) pose an extreme danger and need to be detected very quickly to avoid potential disasters. Gas leaks have the greatest potential for causing damage due to the explosion risk from the dispersion of gas clouds. This paper describes progress towards the development of a fast response, high sensitivity, distributed fiber optic fuel leak detection (HySenseTM) system based on the use of an optical fiber that uses a hydrocarbon sensitive fluorescent coating to detect the presence of fuel leaks present in close proximity along the length of the sensor fiber. The HySenseTM system operates in two modes, leak detection and leak localization, and will trigger an alarm within seconds of exposure contact. The fast and accurate response of the sensor provides reliable fluid leak detection for pipelines, tanks, airports, pumps, and valves to detect and minimize any potential catastrophic damage.

  16. Distributed fiber optic fuel leak detection system

    NASA Astrophysics Data System (ADS)

    Mendoza, Edgar; Kempen, C.; Esterkin, Yan; Sun, Sunjian

    2013-05-01

    With the increase worldwide demand for hydrocarbon fuels and the vast development of new fuel production and delivery infrastructure installations around the world, there is a growing need for reliable fuel leak detection technologies to provide safety and reduce environmental risks. Hydrocarbon leaks (gas or liquid) pose an extreme danger and need to be detected very quickly to avoid potential disasters. Gas leaks have the greatest potential for causing damage due to the explosion risk from the dispersion of gas clouds. This paper describes progress towards the development of a fast response, high sensitivity, distributed fiber optic fuel leak detection (HySensTM) system based on the use of an optical fiber that uses a hydrocarbon sensitive fluorescent coating to detect the presence of fuel leaks present in close proximity along the length of the sensor fiber. The HySenseTM system operates in two modes, leak detection and leak localization, and will trigger an alarm within seconds of exposure contact. The fast and accurate response of the sensor provides reliable fluid leak detection for pipelines, tanks, airports, pumps, and valves to detect and minimize any potential catastrophic damage.

  17. Automated macromolecular crystal detection system and method

    DOEpatents

    Christian, Allen T.; Segelke, Brent; Rupp, Bernard; Toppani, Dominique

    2007-06-05

    An automated macromolecular method and system for detecting crystals in two-dimensional images, such as light microscopy images obtained from an array of crystallization screens. Edges are detected from the images by identifying local maxima of a phase congruency-based function associated with each image. The detected edges are segmented into discrete line segments, which are subsequently geometrically evaluated with respect to each other to identify any crystal-like qualities such as, for example, parallel lines, facing each other, similarity in length, and relative proximity. And from the evaluation a determination is made as to whether crystals are present in each image.

  18. Edge detection techniques for iris recognition system

    NASA Astrophysics Data System (ADS)

    Tania, U. T.; Motakabber, S. M. A.; Ibrahimy, M. I.

    2013-12-01

    Nowadays security and authentication are the major parts of our daily life. Iris is one of the most reliable organ or part of human body which can be used for identification and authentication purpose. To develop an iris authentication algorithm for personal identification, this paper examines two edge detection techniques for iris recognition system. Between the Sobel and the Canny edge detection techniques, the experimental result shows that the Canny's technique has better ability to detect points in a digital image where image gray level changes even at slow rate.

  19. Statistical Fault Detection & Diagnosis Expert System

    SciTech Connect

    Wegerich, Stephan

    1996-12-18

    STATMON is an expert system that performs real-time fault detection and diagnosis of redundant sensors in any industrial process requiring high reliability. After a training period performed during normal operation, the expert system monitors the statistical properties of the incoming signals using a pattern recognition test. If the test determines that statistical properties of the signals have changed, the expert system performs a sequence of logical steps to determine which sensor or machine component has degraded.

  20. Optoelectronic system for NO2 detection

    NASA Astrophysics Data System (ADS)

    Bielecki, Zbigniew; Pregowski, Piotr; Wojtas, Jacek

    2005-10-01

    This paper presents application of Cavity Ring-Down Spectroscopy (CRDS) and Cavity Enhanced Spectroscopic (CEAS) techniques with blue laser diodes-based system for nitrogen dioxide (NO2) detection. CES technique bases on integration of the light from a resonator. Since the integrated intensity is proportional to the decay time, the experimental signal can be related to the absorption process. The minimum detectable concentration of the absorber for a specific transition is inversely proportional to the effective sample-path length, and directly proportional to the minimum intensity fluctuation detected by a receiving system. In the presented system, the blue laser diode was mounted in a temperature-controlled housing. The light transmitted through the cavity was focused onto a PMT of H5783-03 type. The detector signal enters a lock-in amplifier and next a computer with a 16-bit data acquisition board.

  1. A coded aperture imaging system optimized for hard X-ray and gamma ray astronomy

    NASA Technical Reports Server (NTRS)

    Gehrels, N.; Cline, T. L.; Huters, A. F.; Leventhal, M.; Maccallum, C. J.; Reber, J. D.; Stang, P. D.; Teegarden, B. J.; Tueller, J.

    1985-01-01

    A coded aperture imaging system was designed for the Gamma-Ray imaging spectrometer (GRIS). The system is optimized for imaging 511 keV positron-annihilation photons. For a galactic center 511-keV source strength of 0.001 sq/s, the source location accuracy is expected to be + or - 0.2 deg.

  2. A novel mobile system for radiation detection and monitoring

    NASA Astrophysics Data System (ADS)

    Biafore, Mauro

    2014-05-01

    A novel mobile system for real time, wide area radiation surveillance has been developed within the REWARD project, financed within the FP7 programme, theme SEC-2011.1.5-1 (Development of detection capabilities of difficult to detect radioactive sources and nuclear materials - Capability Project). The REWARD sensing units are small, mobile portable units with low energy consumption, which consist of new miniaturized solid-state radiation sensors: a CdZnTe detector for gamma radiation and a high efficiency neutron detector based on novel silicon technologies. The sensing unit is integrated by a wireless communication interface to send the data remotely to a monitoring base station as well as a GPS system to calculate the position of the tag. The system also incorporates middleware and high-level software to provide web-service interfaces for the exchange of information. A central monitoring and decision support system has been designed to process the data from the sensing units and to compare them with historical record in order to generate an alarm when an abnormal situation is detected. A security framework ensures protection against unauthorized access to the network and data, ensuring the privacy of the communications and contributing to the overall robustness and reliability of the REWARD system. The REWARD system has been designed for many different scenarios such as nuclear terrorism threats, lost radioactive sources, radioactive contamination or nuclear accidents. It can be deployed in emergency units and in general in any type of mobile or static equipment, but also inside public/private buildings or infrastructures. The complete system is scalable in terms of complexity and cost and offers very high precision on both the measurement and the location of the radiation. The modularity and flexibility of the system allows for a realistic introduction to the market. Authorities may start with a basic, low cost system and increase the complexity based on their

  3. Readout system for multi-crystal gamma cameras

    DOEpatents

    Derenzo, Stephen E.

    1987-01-01

    A radioisotope camera (10) having an array (12) of scintillation crystals (13) arranged in N rows and M columns and adapted to be struck by gamma-rays from a subject, a separate solid state photodetector (15 ) optically coupled to each crystal (13), and N+M amplifiers (24) connected to the photodetectors (15) to distinguish the particular row and column of an activated photodetector. One of the anode or cathode leads (33 or 34) of each photodetector (15) is coupled to the row amplifier (24) associated with the row containing that photodetector while the other of the two leads (34 or 33) is coupled to the column amplifier (24) associated with the column containing that photodetector.

  4. Water detection at the moon, Mars and comets with a combined neutron gamma ray instrument

    NASA Technical Reports Server (NTRS)

    Metzger, Albert E.; Haines, Eldon L.

    1991-01-01

    Measuring the fluxes of thermal and epithermal neutrons at a planetary object in conjunction with gamma-ray spectroscopic observations will provide information about the chemical composition of the surface which is less model dependent than the gamma ray measurements by themselves. Researchers devised a passive neutron detector for this purpose. An experimental model was designed and built. Three variables provided the basis for a set of experiments: thickness of the Sm and B layers, the presence or absence of the ACS, and the position of the source relative to the PND's cylindrical axis. Experimental results are given.

  5. Fermi LAT Detection of a Rapid, Powerful Gamma-ray Flare of the FSRQ CTA 102

    NASA Astrophysics Data System (ADS)

    Carpenter, Bryce; Ojha, Roopesh

    2015-12-01

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope has observed increasing gamma-ray flux from a source positionally consistent with the flat spectrum radio quasar CTA 102 (also known as 3FGL J2232.5+1143, Acero et al. 2015, ApJS, 218, 23) with radio coordinates R.A.: 338.1517038 deg, Dec: 11.7308067 deg (J2000, Johnston et al. 1995, AJ, 110, 880) at redshift z=1.037 (Schmidt 1965, ApJ, 141, 1295).

  6. Fermi LAT Detection of a Gamma-ray Flare from the BL Lac Object ON 246

    NASA Astrophysics Data System (ADS)

    Becerra, Josefa

    2015-06-01

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope has observed increasing gamma-ray flux from a source positionally consistent with the BL Lac object ON 246 (RA=187.55871 deg, Dec=25.30198 deg, J2000, Beasley et al. 2002, ApJS, 141, 13; with redshift z=0.135, Nass et al. 1996, A&A, 309, 419), also known as S3 1227+25 and 3FGL J1230.3+2519 (3FGL; Acero et al. 2015, arXiv:1501.02003).

  7. Damage detection in initially nonlinear systems

    SciTech Connect

    Bornn, Luke; Farrar, Charles; Park, Gyuhae

    2009-01-01

    The primary goal of Structural Health Monitoring (SHM) is to detect structural anomalies before they reach a critical level. Because of the potential life-safety and economic benefits, SHM has been widely studied over the past decade. In recent years there has been an effort to provide solid mathematical and physical underpinnings for these methods; however, most focus on systems that behave linearly in their undamaged state - a condition that often does not hold in complex 'real world' systems and systems for which monitoring begins mid-lifecycle. In this work, we highlight the inadequacy of linear-based methodology in handling initially nonlinear systems. We then show how the recently developed autoregressive support vector machine (AR-SVM) approach to time series modeling can be used for detecting damage in a system that exhibits initially nonlinear response. This process is applied to data acquired from a structure with induced nonlinearity tested in a laboratory environment.

  8. Fault detection and diagnosis of HVAC systems

    SciTech Connect

    Han, C.Y.; Xiao, Y.; Ruther, C.J.

    1999-07-01

    This paper presents a model-based fault detection and diagnosis (FDD) system for building heating, ventilating, and air conditioning (HVAC). Model-based fault detection is based on the strategy of determining the difference or the residuals between the normal and the existing patterns. Their approach was to attack the problem on many levels of abstraction: from the signal level, controller programming level, and system component, all the way up to the information and knowledge processing level. The various issues of real implementation of the system and the processing of real-time on-line data in actual systems of campus buildings using the proven technology and off-the-shelf commercial tools are discussed. The research was based on input and output points and software control programs found in typical direct digital control systems used for variable-air-volume air handlers and VAV cooling and hot water reheat terminal units.

  9. System for detection of hazardous events

    DOEpatents

    Kulesz, James J.; Worley, Brian A.

    2006-05-23

    A system for detecting the occurrence of anomalies, includes a plurality of spaced apart nodes, with each node having adjacent nodes, each of the nodes having one or more sensors associated with the node and capable of detecting anomalies, and each of the nodes having a controller connected to the sensors associated with the node. The system also includes communication links between adjacent nodes, whereby the nodes form a network. Each controller is programmed to query its adjacent nodes to assess the status of the adjacent nodes and the communication links.

  10. System For Detection Of Hazardous Events

    DOEpatents

    Kulesz, James J [Oak Ridge, TN; Worley, Brian A [Knoxville, TN

    2005-08-16

    A system for detecting the occurrence of anomalies, includes a plurality of spaced apart nodes, with each node having adjacent nodes, each of the nodes having one or more sensors associated with the node and capable of detecting anomalies, and each of the nodes having a controller connected to the sensors associated with the node. The system also includes communication links between adjacent nodes, whereby the nodes form a network. Each controller is programmed to query its adjacent nodes to assess the status of the adjacent nodes and the communication links.

  11. Position Sensitive Detection System for Charged Particles

    SciTech Connect

    Coello, E. A.; Favela, F.; Curiel, Q.; Chavez, E; Huerta, A.; Varela, A.; Shapira, Dan

    2012-01-01

    The position sensitive detection system presented in this work employs the Anger logic algorithm to determine the position of the light spark produced by the passage of charged particles on a 170 x 170 x 10 mm3 scintillator material (PILOT-U). The detection system consists of a matrix of nine photomultipliers, covering a fraction of the back area of the scintillators. Tests made with a non-collimated alpha particle source together with a Monte Carlo simulation that reproduces the data, suggest an intrinsic position resolution of up to 6 mm is achieved.

  12. System for particle concentration and detection

    DOEpatents

    Morales, Alfredo M.; Whaley, Josh A.; Zimmerman, Mark D.; Renzi, Ronald F.; Tran, Huu M.; Maurer, Scott M.; Munslow, William D.

    2013-03-19

    A new microfluidic system comprising an automated prototype insulator-based dielectrophoresis (iDEP) triggering microfluidic device for pathogen monitoring that can eventually be run outside the laboratory in a real world environment has been used to demonstrate the feasibility of automated trapping and detection of particles. The system broadly comprised an aerosol collector for collecting air-borne particles, an iDEP chip within which to temporarily trap the collected particles and a laser and fluorescence detector with which to induce a fluorescence signal and detect a change in that signal as particles are trapped within the iDEP chip.

  13. Idaho Explosives Detection System: Development and Enhancements

    SciTech Connect

    Edward L Reber; Larry G. Blackwood; Andrew J. Edwards; Ann E. Egger; Paul J. Petersen

    2007-12-01

    The Idaho Explosives Detection System (IEDS) was developed at the Idaho National Laboratory (INL) to respond to threats imposed by delivery trucks carrying bulk explosives into military bases. The system consists of two racks, one on each side of a subject vehicle. Each rack includes a neutron generator and an array of sodium iodide (NaI) detectors. The two neutron generators are pulsed and synchronized. A computer connects to the system by Ethernet and is able to control the system remotely. The system was developed to detect bulk explosives in a medium size truck within a 5-minute measurement time. In 2004, a full-scale prototype IEDS system was built for testing and continued development. System performance was successfully tested using different types of real explosives with a variety of cargo at the INL from November 2005 through February 2006. Recently, the first deployable prototype system was constructed and shipped to Wright-Patterson Air Force Base in Ohio and will be in operation by March 2007. The capability of passively detecting radiological material within a delivery truck has also been added.

  14. Driving force for {gamma} {yields} {var{underscore}epsilon} martensitic transformation and stacking fault energy of {gamma} in Fe-Mn binary system

    SciTech Connect

    Lee, Y.K.; Choi, C.S.

    2000-02-01

    A regular solution model for the difference of the chemical free energy between {gamma} and {var{underscore}epsilon} phases during {gamma} {yields} {var{underscore}epsilon} martensitic transformation in the Fe-Mn binary system has been reexamined and partly modified based on many articles concerning the M{sub s} and A{sub s} temperatures of Fe-Mn alloys. Using the regular solution model, the measured M{sub s} temperatures, and a thermodynamic model for the stacking fault energy (SFE) of austenite ({gamma}), the driving force for {gamma} {yields} {epsilon} martensitic transformation, and the SFE of {gamma} have been calculated. The driving force for {gamma} {yields} {epsilon} martensitic transformation increases linearly from {minus}68 to {minus}120 J/mole with increasing Mn content from 16 to 24 wt pct. The SFE of {gamma} decreases to approximately 13 at. pct Mn and then increases with increasing Mn content, which is in better agreement with Schumann's result rather than Volosevich et al.'s result.

  15. Development of an all-in-one gamma camera/CCD system for safeguard verification

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Il; An, Su Jung; Chung, Yong Hyun; Kwak, Sung-Woo

    2014-12-01

    For the purpose of monitoring and verifying efforts at safeguarding radioactive materials in various fields, a new all-in-one gamma camera/charged coupled device (CCD) system was developed. This combined system consists of a gamma camera, which gathers energy and position information on gamma-ray sources, and a CCD camera, which identifies the specific location in a monitored area. Therefore, 2-D image information and quantitative information regarding gamma-ray sources can be obtained using fused images. A gamma camera consists of a diverging collimator, a 22 × 22 array CsI(Na) pixelated scintillation crystal with a pixel size of 2 × 2 × 6 mm3 and Hamamatsu H8500 position-sensitive photomultiplier tube (PSPMT). The Basler scA640-70gc CCD camera, which delivers 70 frames per second at video graphics array (VGA) resolution, was employed. Performance testing was performed using a Co-57 point source 30 cm from the detector. The measured spatial resolution and sensitivity were 4.77 mm full width at half maximum (FWHM) and 7.78 cps/MBq, respectively. The energy resolution was 18% at 122 keV. These results demonstrate that the combined system has considerable potential for radiation monitoring.

  16. SWEPP gamma-ray spectrometer system software user`s guide

    SciTech Connect

    Femec, D.A.

    1994-08-01

    The SWEPP Gamma-Ray Spectrometer (SGRS) System has been developed by the Radiation Measurement and Development Unit of the Idaho National Engineering Laboratory to assist in the characterization of the radiological contents of contact-handled waste containers at the Stored Waste Examination Pilot Plant (SWEPP). In addition to determining the concentrations of gamma-ray-emitting radionuclides, the software also calculates attenuation-corrected isotopic mass ratios of specific interest, and provides controls for SGRS hardware as required. This document serves as a user`s guide for the data acquisition and analysis software associated with the SGRS system.

  17. Performance Evaluation of Hyperspectral Chemical Detection Systems

    NASA Astrophysics Data System (ADS)

    Truslow, Eric

    Remote sensing of chemical vapor plumes is a difficult but important task with many military and civilian applications. Hyperspectral sensors operating in the long wave infrared (LWIR) regime have well demonstrated detection capabilities. However, the identification of a plume's chemical constituents, based on a chemical library, is a multiple hypothesis-testing problem that standard detection metrics do not fully describe. Our approach partitions and weights a confusion matrix to develop both the standard detection metrics and an identification metric based on the Dice index. Using the developed metrics, we demonstrate that using a detector bank followed by an identifier can achieve superior performance relative to either algorithm individually. Performance of the cascaded system relies on the first pass reliably detecting the plume. However, detection performance is severely hampered by the inclusion of plume pixels in estimates of background quantities. We demonstrate that this problem, known as contamination, can be mitigated by iteratively applying a spatial filter to the detected pixels. Multiple detection and filtering passes can remove nearly all contamination from the background estimates, a vast improvement over single-pass techniques.

  18. Spark discharge trace element detection system

    DOEpatents

    Adler-Golden, Steven; Bernstein, Lawrence S.; Bien, Fritz

    1988-01-01

    A spark discharge trace element detection system is provided which includes a spark chamber including a pair of electrodes for receiving a sample of gas to be analyzed at no greater than atmospheric pressure. A voltage is provided across the electrodes for generating a spark in the sample. The intensity of the emitted radiation in at least one primary selected narrow band of the radiation is detected. Each primary band corresponds to an element to be detected in the gas. The intensity of the emission in each detected primary band is integrated during the afterglow time interval of the spark emission and a signal representative of the integrated intensity of the emission in each selected primary bond is utilized to determine the concentration of the corresponding element in the gas.

  19. Spark discharge trace element detection system

    DOEpatents

    Adler-Golden, S.; Bernstein, L.S.; Bien, F.

    1988-08-23

    A spark discharge trace element detection system is provided which includes a spark chamber including a pair of electrodes for receiving a sample of gas to be analyzed at no greater than atmospheric pressure. A voltage is provided across the electrodes for generating a spark in the sample. The intensity of the emitted radiation in at least one primary selected narrow band of the radiation is detected. Each primary band corresponds to an element to be detected in the gas. The intensity of the emission in each detected primary band is integrated during the afterglow time interval of the spark emission and a signal representative of the integrated intensity of the emission in each selected primary bond is utilized to determine the concentration of the corresponding element in the gas. 12 figs.

  20. Mobile, hybrid Compton/coded aperture imaging for detection, identification and localization of gamma-ray sources at stand-off distances

    NASA Astrophysics Data System (ADS)

    Tornga, Shawn R.

    The Stand-off Radiation Detection System (SORDS) program is an Advanced Technology Demonstration (ATD) project through the Department of Homeland Security's Domestic Nuclear Detection Office (DNDO) with the goal of detection, identification and localization of weak radiological sources in the presence of large dynamic backgrounds. The Raytheon-SORDS Tri-Modal Imager (TMI) is a mobile truck-based, hybrid gamma-ray imaging system able to quickly detect, identify and localize, radiation sources at standoff distances through improved sensitivity while minimizing the false alarm rate. Reconstruction of gamma-ray sources is performed using a combination of two imaging modalities; coded aperture and Compton scatter imaging. The TMI consists of 35 sodium iodide (NaI) crystals 5x5x2 in3 each, arranged in a random coded aperture mask array (CA), followed by 30 position sensitive NaI bars each 24x2.5x3 in3 called the detection array (DA). The CA array acts as both a coded aperture mask and scattering detector for Compton events. The large-area DA array acts as a collection detector for both Compton scattered events and coded aperture events. In this thesis, developed coded aperture, Compton and hybrid imaging algorithms will be described along with their performance. It will be shown that multiple imaging modalities can be fused to improve detection sensitivity over a broader energy range than either alone. Since the TMI is a moving system, peripheral data, such as a Global Positioning System (GPS) and Inertial Navigation System (INS) must also be incorporated. A method of adapting static imaging algorithms to a moving platform has been developed. Also, algorithms were developed in parallel with detector hardware, through the use of extensive simulations performed with the Geometry and Tracking Toolkit v4 (GEANT4). Simulations have been well validated against measured data. Results of image reconstruction algorithms at various speeds and distances will be presented as well as

  1. Materiel requirements for airborne minefield detection system

    NASA Astrophysics Data System (ADS)

    Bertsche, Karl A.; Huegle, Helmut

    1997-07-01

    Within the concept study, Material Requirements for an airborne minefield detection systems (AMiDS) the following topics were investigated: (i) concept concerning airborne minefield detection technique sand equipment, (ii) verification analysis of the AMiDS requirements using simulation models and (iii) application concept of AMiDS with regard o tactics and military operations. In a first approach the problems concerning unmanned airborne minefield detection techniques within a well-defined area were considered. The complexity of unmanned airborne minefield detection is a result of the following parameters: mine types, mine deployment methods, tactical requirements, topography, weather conditions, and the size of the area to be searched. In order to perform the analysis, a simulation model was developed to analyze the usability of the proposed remote controlled air carriers. The basic flight patterns for the proposed air carriers, as well as the preparation efforts of military operations and benefits of such a system during combat support missions were investigated. The results of the conceptual study showed that a proposed remote controlled helicopter drone could meet the stated German MOD scanning requirements of mine barriers. Fixed wing air carriers were at a definite disadvantage because of their inherently large turning loops. By implementing a mine detection system like AMiDS minefields can be reconnoitered before an attack. It is therefore possible either to plan, how the minefields can be circumvented or where precisely breaching lanes through the mine barriers are to be cleared for the advancing force.

  2. Lithium-containing scintillators for thermal neutron, fast neutron, and gamma detection

    DOEpatents

    Zaitseva, Natalia P.; Carman, M. Leslie; Faust, Michelle A.

    2016-03-01

    In one embodiment, a scintillator includes a scintillator material; a primary fluor, and a Li-containing compound, where the Li-containing compound is soluble in the primary fluor, and where the scintillator exhibits an optical response signature for thermal neutrons that is different than an optical response signature for fast neutrons and gamma rays.

  3. Neutron detection in a high-gamma field using solution-grown stilbene

    NASA Astrophysics Data System (ADS)

    Bourne, M. M.; Clarke, S. D.; Adamowicz, N.; Pozzi, S. A.; Zaitseva, N.; Carman, L.

    2016-01-01

    A solution-based technique for growing large-volume stilbene scintillators was developed in 2013; crystals up to diameters of 10 cm, or larger, have been grown while preserving excellent pulse shape discrimination (PSD) properties. The goal of this study is to evaluate the PSD capabilities of 5.08 by 5.08-cm stilbene crystals grown by Lawrence Livermore National Laboratory and Inrad Optics when exposed to a 1000 to 1 gamma ray-neutron ratio and operating at a 100-kHz count rate. Results were compared to an equivalent EJ-309 liquid scintillation detector. 252Cf neutron pulses were recorded in two experiments where 60Co and 137Cs sources created the high-gamma field. The high count rate created numerous double pulses that were cleaned using fractional and template approaches designed to remove double pulses while preserving neutron counts. PSD was performed at a threshold of 42 keVee (440-keV proton) for stilbene and 60 keVee (610-keV proton) for EJ-309 liquid. The lower threshold in stilbene resulted in a neutron intrinsic efficiency of approximately 14.5%, 10% higher than EJ-309 liquid, for bare 252Cf and 13% for 252Cf in the high-gamma field. Despite the lower threshold, the gamma misclassification rate in stilbene was approximately 3×10-6, nearly a factor-of-five lower than what we found with the EJ-309 liquid.

  4. Immunity-Based Aircraft Fault Detection System

    NASA Technical Reports Server (NTRS)

    Dasgupta, D.; KrishnaKumar, K.; Wong, D.; Berry, M.

    2004-01-01

    In the study reported in this paper, we have developed and applied an Artificial Immune System (AIS) algorithm for aircraft fault detection, as an extension to a previous work on intelligent flight control (IFC). Though the prior studies had established the benefits of IFC, one area of weakness that needed to be strengthened was the control dead band induced by commanding a failed surface. Since the IFC approach uses fault accommodation with no detection, the dead band, although it reduces over time due to learning, is present and causes degradation in handling qualities. If the failure can be identified, this dead band can be further A ed to ensure rapid fault accommodation and better handling qualities. The paper describes the application of an immunity-based approach that can detect a broad spectrum of known and unforeseen failures. The approach incorporates the knowledge of the normal operational behavior of the aircraft from sensory data, and probabilistically generates a set of pattern detectors that can detect any abnormalities (including faults) in the behavior pattern indicating unsafe in-flight operation. We developed a tool called MILD (Multi-level Immune Learning Detection) based on a real-valued negative selection algorithm that can generate a small number of specialized detectors (as signatures of known failure conditions) and a larger set of generalized detectors for unknown (or possible) fault conditions. Once the fault is detected and identified, an adaptive control system would use this detection information to stabilize the aircraft by utilizing available resources (control surfaces). We experimented with data sets collected under normal and various simulated failure conditions using a piloted motion-base simulation facility. The reported results are from a collection of test cases that reflect the performance of the proposed immunity-based fault detection algorithm.

  5. DCE Bio Detection System Final Report

    SciTech Connect

    Lind, Michael A.; Batishko, Charles R.; Morgen, Gerald P.; Owsley, Stanley L.; Dunham, Glen C.; Warner, Marvin G.; Willett, Jesse A.

    2007-12-01

    The DCE (DNA Capture Element) Bio-Detection System (Biohound) was conceived, designed, built and tested by PNNL under a MIPR for the US Air Force under the technical direction of Dr. Johnathan Kiel and his team at Brooks City Base in San Antonio Texas. The project was directed toward building a measurement device to take advantage of a unique aptamer based assay developed by the Air Force for detecting biological agents. The assay uses narrow band quantum dots fluorophores, high efficiency fluorescence quenchers, magnetic micro-beads beads and selected aptamers to perform high specificity, high sensitivity detection of targeted biological materials in minutes. This final report summarizes and documents the final configuration of the system delivered to the Air Force in December 2008

  6. A Web Based Cardiovascular Disease Detection System.

    PubMed

    Alshraideh, Hussam; Otoom, Mwaffaq; Al-Araida, Aseel; Bawaneh, Haneen; Bravo, José

    2015-10-01

    Cardiovascular Disease (CVD) is one of the most catastrophic and life threatening health issue nowadays. Early detection of CVD is an important solution to reduce its devastating effects on health. In this paper, an efficient CVD detection algorithm is identified. The algorithm uses patient demographic data as inputs, along with several ECG signal features extracted automatically through signal processing techniques. Cross-validation results show a 98.29 % accuracy for the decision tree classification algorithm. The algorithm has been integrated into a web based system that can be used at anytime by patients to check their heart health status. At one end of the system is the ECG sensor attached to the patient's body, while at the other end is the detection algorithm. Communication between the two ends is done through an Android application. PMID:26293754

  7. Methods and systems for detection of radionuclides

    DOEpatents

    Coates, Jr., John T.; DeVol, Timothy A.

    2010-05-25

    Disclosed are materials and systems useful in determining the existence of radionuclides in an aqueous sample. The materials provide the dual function of both extraction and scintillation to the systems. The systems can be both portable and simple to use, and as such can beneficially be utilized to determine presence and optionally concentration of radionuclide contamination in an aqueous sample at any desired location and according to a relatively simple process without the necessity of complicated sample handling techniques. The disclosed systems include a one-step process, providing simultaneous extraction and detection capability, and a two-step process, providing a first extraction step that can be carried out in a remote field location, followed by a second detection step that can be carried out in a different location.

  8. Digital radiographic systems detect boiler tube cracks

    SciTech Connect

    Walker, S.

    2008-06-15

    Boiler water wall leaks have been a major cause of steam plant forced outages. But conventional nondestructive evaluation techniques have a poor track record of detecting corrosion fatigue cracking on the inside surface of the cold side of waterwall tubing. EPRI is performing field trials of a prototype direct-digital radiographic system that promises to be a game changer. 8 figs.

  9. Detection of abrupt changes in dynamic systems

    NASA Technical Reports Server (NTRS)

    Willsky, A. S.

    1984-01-01

    Some of the basic ideas associated with the detection of abrupt changes in dynamic systems are presented. Multiple filter-based techniques and residual-based method and the multiple model and generalized likelihood ratio methods are considered. Issues such as the effect of unknown onset time on algorithm complexity and structure and robustness to model uncertainty are discussed.

  10. Portable light detection system for the blind

    NASA Technical Reports Server (NTRS)

    Wilber, R. L.; Carpenter, B. L.

    1973-01-01

    System can be used to detect "ready" light on automatic cooking device, to tell if lights are on for visitors, or to tell whether it is daylight or dark outside. Device is actuated like flashlight. Light impinging on photo cell activates transistor which energizes buzzer to indicate presence of light.

  11. EGRET detection of high-energy gamma radiation from the OVV quasar 3C 454.3

    NASA Technical Reports Server (NTRS)

    Hartman, R. C.; Bertsch, D. L.; Dingus, B. L.; Fichtel, C. E.; Hunter, S. D.; Kanbach, G.; Kniffen, D. A.; Lin, Y. C.; Mattox, J. R.; Mayer-Hasselwander, H. A.

    1993-01-01

    High-energy gamma radiation has been observed from the optically violent variable quasar 3C 454.3 (PKS 2251 + 158) by the Energetic Gamma-Ray Experiment Telescope on the Compton Observatory. During the 1992 January-February observation, the emission showed a power-law photon spectrum with an exponent of -2.18 +/- 0.08. The flux density (greater than 100 MeV) was observed to vary within the range (0.4-1.4) x 10 exp -6 photon/sq cm s on a time scale of less than a week. Lower sensitivity observations during 1992 April and May also detected emission within that range, but with lower statistical significance. An earlier low-sensitivity exposure during 1991 August gave a 95 percent confidence upper limit of 0.26 x 10 exp 6 photon/sq cm s. The similarity of the gamma-ray emission of 3C 454.3 to that of 3C 279 parallels the similarity of these two objects at lower frequencies.

  12. Landmine detection by 3D GPR system

    NASA Astrophysics Data System (ADS)

    Sato, Motoyuki; Yokota, Yuya; Takahashi, Kazunori; Grasmueck, Mark

    2012-06-01

    In order to demonstrate the possibility of Ground Penetrating Radar (GPR) for detection of small buried objects such as landmine and UXO, conducted demonstration tests by using the 3DGPR system, which is a GPR system combined with high accuracy positing system using a commercial laser positioning system (iGPS). iGPS can provide absolute and better than centimetre precise x,y,z coordinates to multiple mine sensors at the same time. The developed " 3DGPR" system is efficient and capable of high-resolution 3D shallow subsurface scanning of larger areas (25 m2 to thousands of square meters) with irregular topography . Field test by using a 500MHz GPR system equipped with 3DGPR system was conducted. PMN-2 and Type-72 mine models have been buried at the depth of 5-20cm in sand. We could demonstrate that the 3DGPR can visualize each of these buried land mines very clearly.

  13. Total Measurement Uncertainty for the Plutonium Finishing Plant (PFP) Segmented Gamma Scan Assay System

    SciTech Connect

    WESTSIK, G.A.

    2001-06-06

    This report presents the results of an evaluation of the Total Measurement Uncertainty (TMU) for the Canberra manufactured Segmented Gamma Scanner Assay System (SGSAS) as employed at the Hanford Plutonium Finishing Plant (PFP). In this document, TMU embodies the combined uncertainties due to all of the individual random and systematic sources of measurement uncertainty. It includes uncertainties arising from corrections and factors applied to the analysis of transuranic waste to compensate for inhomogeneities and interferences from the waste matrix and radioactive components. These include uncertainty components for any assumptions contained in the calibration of the system or computation of the data. Uncertainties are propagated at 1 sigma. The final total measurement uncertainty value is reported at the 95% confidence level. The SGSAS is a gamma assay system that is used to assay plutonium and uranium waste. The SGSAS system can be used in a stand-alone mode to perform the NDA characterization of a container, particularly for low to medium density (0-2.5 g/cc) container matrices. The SGSAS system provides a full gamma characterization of the container content. This document is an edited version of the Rocky Flats TMU Report for the Can Scan Segment Gamma Scanners, which are in use for the plutonium residues projects at the Rocky Flats plant. The can scan segmented gamma scanners at Rocky Flats are the same design as the PFP SGSAS system and use the same software (with the exception of the plutonium isotopics software). Therefore, all performance characteristics are expected to be similar. Modifications in this document reflect minor differences in the system configuration, container packaging, calibration technique, etc. These results are supported by the Quality Assurance Objective (QAO) counts, safeguards test data, calibration data, etc. for the PFP SGSAS system. Other parts of the TMU analysis utilize various modeling techniques such as Monte Carlo N

  14. Systems and methods for detecting nuclear radiation in the presence of backgrounds

    DOEpatents

    Bross, Alan D.; Mellott, Kerry L.; Pla-Dalmau, Anna

    2005-06-21

    Systems and methods for the simultaneous detection and identification of radiation species, including neutrons, gammas/x-rays and minimum ionizing particles (MIPs). A plurality of rectangular and/or triangularly shaped radiation sensitive scintillators can be configured from a plurality of nano-sized particles, dopants and an extruded plastic material. A wavelength-shifting fiber can then be located within a central hole of each extruded scintillator, wherein the wavelength-shifting fiber absorbs scintillation light and re-emits the light at a longer wavelength, thereby piping the light to a photodetector whose response to the light indicates the presence of radiation The resulting method and system can simultaneously detect neutrons, gamma rays, x-rays and cosmic rays (MIPs) and identify each.

  15. Kernel Integration Code System--Multigroup Gamma-Ray Scattering.

    Energy Science and Technology Software Center (ESTSC)

    1988-02-15

    GGG (G3) is the generic designation for a series of computer programs that enable the user to estimate gamma-ray scattering from a point source to a series of point detectors. Program output includes detector response due to each source energy, as well as a grouping by scattered energy in addition to a simple, unscattered beam result. Although G3 is basically a single-scatter program, it also includes a correction for multiple scattering by applying a buildupmore » factor for the path segment between the point of scatter and the detector point. Results are recorded with and without the buildup factor. Surfaces, defined by quadratic equations, are used to provide for a full three-dimensional description of the physical geometry. G3 evaluates scattering effects in those situations where more exact techniques are not economical. G3 was revised by Bettis and the name was changed to indicate that it was no longer identical to the G3 program. The name S3 was chosen since the scattering calculation has three steps: calculation of the flux arriving at the scatterer from the point source, calculation of the differential scattering cross section, and calculation of the scattered flux arriving at the detector.« less

  16. 46 CFR 108.405 - Fire detection system.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Fire detection system. 108.405 Section 108.405 Shipping... EQUIPMENT Fire Extinguishing Systems § 108.405 Fire detection system. (a) Each fire detection system and...) Each fire detection system must be divided into zones to limit the area covered by any particular...

  17. 46 CFR 108.405 - Fire detection system.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Fire detection system. 108.405 Section 108.405 Shipping... EQUIPMENT Fire Extinguishing Systems § 108.405 Fire detection system. (a) Each fire detection system and...) Each fire detection system must be divided into zones to limit the area covered by any particular...

  18. Monte Carlo simulation of a collimation system for low-energy beamline of ELI-NP Gamma Beam System

    NASA Astrophysics Data System (ADS)

    Cardarelli, P.; Gambaccini, M.; Marziani, M.; Bagli, E.; Petrillo, V.; Bacci, A.; Curatolo, C.; Drebot, I.; Vaccarezza, C.

    2015-07-01

    ELI-nuclear physics (NP) Gamma Beam System (GBS) is an intense and monochromatic gamma beam source based on inverse Compton interaction, currently being built in Bucharest, Romania. The gamma beam produced, with energy ranging from 0.2 to 20 MeV, energy bandwidth 0.5% and flux of about 108photons/s, will be devoted to investigate a broad range of applications such as nuclear physics, astrophysics, material science and life sciences. The radiation produced by an inverse Compton interaction is not intrinsically monochromatic. In fact, the energy of the photons produced is related to the emission angle, therefore the energy bandwidth can be modified adjusting the collimation of the gamma beam. In order to define the optimal layout and evaluate the performance of a collimation system for the ELI-NP-GBS low-energy beamline (0.2-3.5 MeV), a detailed Monte Carlo simulation activity has been carried out. The simulation, using Geant4 and MCNPX codes, included the transport of the gamma beam from the interaction point to the experimental area passing through vacuum pipes, vacuum chambers, collimation system and relative shielding. The effectiveness of the collimation system, in obtaining the required energy distribution and avoiding the contamination due to secondary radiation production, was evaluated. Also, the background radiation generated by collimation and the shielding layout have been studied.

  19. Low background high efficiency radiocesium detection system based on positron emission tomography technology

    SciTech Connect

    Yamamoto, Seiichi; Ogata, Yoshimune

    2013-09-15

    After the 2011 nuclear power plant accident at Fukushima, radiocesium contamination in food became a serious concern in Japan. However, low background and high efficiency radiocesium detectors are expensive and huge, including semiconductor germanium detectors. To solve this problem, we developed a radiocesium detector by employing positron emission tomography (PET) technology. Because {sup 134}Cs emits two gamma photons (795 and 605 keV) within 5 ps, they can selectively be measured with coincidence. Such major environmental gamma photons as {sup 40}K (1.46 MeV) are single photon emitters and a coincidence measurement reduces the detection limit of radiocesium detectors. We arranged eight sets of Bi{sub 4}Ge{sub 3}O{sub 12} (BGO) scintillation detectors in double rings (four for each ring) and measured the coincidence between these detectors using PET data acquisition system. A 50 × 50 × 30 mm BGO was optically coupled to a 2 in. square photomultiplier tube (PMT). By measuring the coincidence, we eliminated most single gamma photons from the energy distribution and only detected those from {sup 134}Cs at an average efficiency of 12%. The minimum detectable concentration of the system for the 100 s acquisition time is less than half of the food monitor requirements in Japan (25 Bq/kg). These results show that the developed radiocesium detector based on PET technology is promising to detect low level radiocesium.

  20. Low background high efficiency radiocesium detection system based on positron emission tomography technology.

    PubMed

    Yamamoto, Seiichi; Ogata, Yoshimune

    2013-09-01

    After the 2011 nuclear power plant accident at Fukushima, radiocesium contamination in food became a serious concern in Japan. However, low background and high efficiency radiocesium detectors are expensive and huge, including semiconductor germanium detectors. To solve this problem, we developed a radiocesium detector by employing positron emission tomography (PET) technology. Because (134)Cs emits two gamma photons (795 and 605 keV) within 5 ps, they can selectively be measured with coincidence. Such major environmental gamma photons as (40)K (1.46 MeV) are single photon emitters and a coincidence measurement reduces the detection limit of radiocesium detectors. We arranged eight sets of Bi4Ge3O12 (BGO) scintillation detectors in double rings (four for each ring) and measured the coincidence between these detectors using PET data acquisition system. A 50 × 50 × 30 mm BGO was optically coupled to a 2 in. square photomultiplier tube (PMT). By measuring the coincidence, we eliminated most single gamma photons from the energy distribution and only detected those from (134)Cs at an average efficiency of 12%. The minimum detectable concentration of the system for the 100 s acquisition time is less than half of the food monitor requirements in Japan (25 Bq/kg). These results show that the developed radiocesium detector based on PET technology is promising to detect low level radiocesium. PMID:24089828