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Building a dedicated information barrier system for warhead and sensitive item verification

Description: This paper documents the development of a dedicated information barrier system for warhead and sensitive item verification. The system the authors describe includes software and hardware information barriers used in conjunction with suitable procedures (or protocols) to achieve a high quality verification while minimizing intrusiveness and preventing transfer of sensitive data to inspectors. The system they describe has been referred to as CIVET--Controlled Intrusiveness Verification Technology… more
Date: July 25, 1999
Creator: ZUHOSKI,P.B.; INDUSI,J.P. & VANIER,P.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A NEW METHDOLOGY FOR DETERMINING FISSILE MASS IN INDIVIDUAL ACCOUNTING ITEMS WITH THE USE OF GAMMA-RAY SPECTROMETRY.

Description: In the safeguards, arms control, and nonproliferation regimes measurements are required which give the quantity of fissile material in an accounting item, e.g., a standard container of plutonium or uranium oxide. Because of the complexity of modeling the absorption of gamma rays in high-Z materials, gamma-ray spectrometry is not customarily used for this purpose. Gamma-ray measurements can be used to determine the fissile mass when two conditions are met: (1) The material is in a standard conta… more
Date: July 16, 2000
Creator: KANE,W.R.; VANIER,P.E.; ZUHOSKI,P.B. & LEMLEY,J.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Thermal neutron imaging support with other laboratories BL06-IM-TNI

Description: The goals of this project are: (1) detect and locate a source of thermal neutrons; (2) distinguish a localized source from uniform background; (3) show shape and size of thermalizing material; (4) test thermal neutron imager in active interrogation environment; and (5) distinguish delayed neutrons from prompt neutrons.
Date: June 17, 2008
Creator: Vanier, P. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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IMPROVEMENTS IN CODED APERTURE THERMAL NEUTRON IMAGING.

Description: A new thermal neutron imaging system has been constructed, based on a 20-cm x 17-cm He-3 position-sensitive detector with spatial resolution better than 1 mm. New compact custom-designed position-decoding electronics are employed, as well as high-precision cadmium masks with Modified Uniformly Redundant Array patterns. Fast Fourier Transform algorithms are incorporated into the deconvolution software to provide rapid conversion of shadowgrams into real images. The system demonstrates the princi… more
Date: August 3, 2003
Creator: VANIER,P. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Analogies Between Neutron and Gamma-Ray Imaging.

Description: Although the physics describing the interactions of neutrons with matter is quite different from that appropriate for hard x-rays and gamma rays, there are a number of similarities that allow analogous instruments to be developed for both types of ionizing radiation. A pinhole camera, for example, requires that the radiation obeys some form of geometrical optics, that a material can be found to absorb some of the radiation, and that a suitable position-sensitive detector can be built to record … more
Date: August 13, 2006
Creator: Vanier, P. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Calibration and Testing of a Large-Area Fast-Neutron Directional Detector.

Description: We have developed a new directional fast-neutron detector based on double proton recoil in two separated planes of plastic scintillators with position-sensitive readout. This method allows the energy spectrum of the neutrons to be measured by a combination of peak amplitude in the first plane and time of flight to the second plane. The planes are made up of 1-m long, 10-cm high paddles with photomultipliers at both ends, so that the location of an event along the paddle can be estimated from th… more
Date: May 16, 2007
Creator: Vanier, P. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Directional Detection of Fission-Spectrum Neutrons.

Description: Conventional neutron detectors consisting of {sup 3}He tubes surrounded by a plastic moderator can be quite efficient in detecting fission spectrum neutrons, but do not indicate the direction of the incident radiation. We have developed a new directional detector based on double proton recoil in two separated planes of plastic scintillators. This method allows the spectrum of the neutrons to be measured by a combination of peak amplitude in the first plane and time of flight to the second plane… more
Date: May 4, 2007
Creator: Vanier, P. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Design of a Large-Area Fast Neutron Directional Detector.

Description: A large-area fast-neutron double-scatter directional detector and spectrometer is being constructed using l-meter-long plastic scintillator paddles with photomultiplier tubes at both ends. The scintillators detect fast neutrons by proton recoil and also gamma rays by Compton scattering. The paddles are arranged in two parallel planes so that neutrons can be distinguished from muons and gamma rays by time of flight between the planes. The signal pulses are digitized with a time resolution of one… more
Date: October 29, 2006
Creator: Vanier, P. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Adaptation of a neutron diffraction detector to coded aperture imaging

Description: A coded aperture neutron imaging system developed at Brookhaven National Laboratory (BNL) has demonstrated that it is possible to record not only a flux of thermal neutrons at some position, but also the directions from whence they came. This realization of an idea which defied the conventional wisdom has provided a device which has never before been available to the nuclear physics community. A number of potential applications have been explored, including (1) counting warheads on a bus or in … more
Date: February 1, 1997
Creator: Vanier, P. E. & Forman, L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Advances in imaging with thermal neutrons

Description: Experiments have been conducted using a modern high-resolution {sup 3}He two-dimensional position-sensitive detection chamber combined with coded apertures to produce images by means of thermal neutrons. These images are comparable to those produced by gamma ray imaging, but with some important differences. The detector is much less sensitive to the fast neutrons than to the thermalized component. Therefore, assuming that the neutron source has a fission spectrum, the brightest regions in an im… more
Date: September 1, 1996
Creator: Vanier, P. E. & Forman, L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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X-ray emission yields from both surfaces of thin targets bombarded with a 200-MeV H sup minus beam

Description: A modified commercial energy-dispersive x-ray spectrometer was used to measure the yields of characteristic x rays from elemental and alloy targets irradiated by a 200-MeV negative-hydrogen beam. In most cases the entry surface, which was bombarded by both electrons and protons, gave about a factor of 2 higher yield than the exit surface where the stripped protons emerged. The results suggest a method of measuring beam profiles where particle densities are too low to be detected electrically by… more
Date: January 1, 1988
Creator: Vanier, P. E.; Zucker, M. S. & Snead Jr., C. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Xenon Gamma Detector Project Support

Description: This project provided funding of $48,500 for part of one year to support the development of compressed xenon spectrometers at BNL. This report describes upgrades that were made to the existing detector system electronics during that period, as well as subsequent testing with check sources and Special Nuclear Materials. Previous testing of the equipment extended only up to the energy of 1.3 MeV, and did not include a spectrum of Pu-239. The new electronics allowed one-button activation of the hi… more
Date: April 1, 2008
Creator: Vanier, P. E. & Forman, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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An 8-Element Fast-Neutron Double-Scatter Directional Detector.

Description: We have constructed a fast-neutron double-scatter spectrometer that efficiently measures the neutron spectrum and direction of a spontaneous fission source. The device consists of two planes of organic scintillators, each having an area of 125 cm{sup 2}, efficiently coupled to photomultipliers. The four scintillators in the front plane are 2 cm thick, giving almost 25% probability of detecting an incident fission-spectrum neutron at 2 MeV by proton recoil and subsequent ionization. The back pla… more
Date: July 31, 2005
Creator: Vanier, P. E. & Forman, L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Directional Detection of a Neutron Source.

Description: Advantages afforded by the development of new directional neutron detectors and imagers are discussed. Thermal neutrons have mean free paths in air of about 20 meters, and can be effectively imaged using coded apertures. Fission spectrum neutrons have ranges greater than 100 meters, and carry enough energy to scatter at least twice in multilayer detectors which can yield both directional and spectral information. Such strategies allow better discrimination between a localized spontaneous fissio… more
Date: October 23, 2006
Creator: Vanier, P. E. & Forman, L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Advanced amorphous materials for photovoltaic conversion. Annual report, October 1, 1978-September 30, 1979

Description: The objectives of this project are twofold: (1) to investigate new amorphous semiconductor (a-SC) materials, in which recombination centers are passivated, using plasma deposition techniques; and (2) to characterize the optoelectronic properties pertaining to both majority-carrier and minority-carrier transport in as-deposited films and in devices. The electronic properties of plasma-deposited a-Si:H alloys were studied as functions of oxygen and nitrogen impurities. Over a wide range of proces… more
Date: January 1, 1980
Creator: Griffith, R. W.; Kampas, F. J.; Vanier, P. E. & Hirsch, M. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Modifications in optoelectronic behavior of plasma-deposited amorphous semiconductor alloys via impurity incorporation

Description: Electronic properties of plasma-deposited a-Si:H alloys are discussed as functions of oxygen and nitrogen impurities. Over a wide range of processing conditions, features displayed by the data include: (1) anomalous behavior in photoconductivity versus temperature for films deficient in either, or both, impurities (peaks appear that are associated with thermal-quenching processes and supralinearity); (2) modification to classic behavior in photoconductivity owing to synergistic effects of oxyge… more
Date: January 1, 1979
Creator: Griffith, R. W.; Kampas, F. J.; Vanier, P. E. & Hirsch, M. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A thermal neutron source imager using coded apertures

Description: To facilitate the process of re-entry vehicle on-site inspections, it would be useful to have an imaging technique which would allow the counting of deployed multiple nuclear warheads without significant disassembly of a missile`s structure. Since neutrons cannot easily be shielded without massive amounts of materials, they offer a means of imaging the separate sources inside a sealed vehicle. Thermal neutrons carry no detailed spectral information, so their detection should not be as intrusive… more
Date: August 1, 1995
Creator: Vanier, P. E.; Forman, L. & Selcow, E. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Testing of protective coatings in hydrogen

Description: A series of tests of protective coatings on carbon-carbon substrates were performed. The tests involved exposure of the coated material to hydrogen at high temperatures, the examination of the coatings by scanning electron microscopy and the measurement of weight losses. The coatings included Re, TaHfC, TaC and NbC, with thicknesses of the order of 20--60 {mu}m.
Date: July 1, 1993
Creator: Vanier, P. E.; Barletta, R.; Adams, J. & Svandrlik, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Tests of Hercules/Ultramet CVD coatings in hot hydrogen

Description: The effort by Hercules and Ultramet to produce CVD NbC coatings, which protect carbon-carbon substrates from hot hydrogen, has had some success but with some limitations. The coatings increase the survival time at atmospheric pressure and low flow rate of hydrogen by about a factor of 40 over uncoated graphite at 3000 K. However, the grain structure is not stable at these temperatures, and after about 10--20 minutes, the coating is subject to rapid degradation by spalling in visible chunks. Fur… more
Date: January 1, 1992
Creator: Vanier, P. E.; Barletta, R. E.; Svandrlik, J. & Adams, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Deposition and modification of tantalum carbide coatings on graphite by laser interactions

Description: Graphite surfaces can be hardened and protected from erosion by hydrogen at high temperatures by refractory metal carbide coatings, which are usually prepared by chemical vapor deposition (CVD) or chemical vapor reaction (CVR) methods. These techniques rely on heating the substrate to a temperature where a volatile metal halide decomposes and reacts with either a hydrocarbon gas or with carbon from the substrate. For CVR techniques, deposition temperatures must be in excess of 2000[degrees]C in… more
Date: January 1, 1992
Creator: Veligdan, J.; Branch, D.; Vanier, P. E. & Barletta, R. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Deposition and modification of tantalum carbide coatings on graphite by laser interactions

Description: Graphite surfaces can be hardened and protected from erosion by hydrogen at high temperatures by refractory metal carbide coatings, which are usually prepared by chemical vapor deposition (CVD) or chemical vapor reaction (CVR) methods. These techniques rely on heating the substrate to a temperature where a volatile metal halide decomposes and reacts with either a hydrocarbon gas or with carbon from the substrate. For CVR techniques, deposition temperatures must be in excess of 2000{degrees}C in… more
Date: December 31, 1992
Creator: Veligdan, J.; Branch, D.; Vanier, P. E. & Barletta, R. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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