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Advanced High-Speed 16-Bit Digitizer System

Description: The fastest commercially available 16-bit ADC can only perform around 200 mega-samples per second (200 MS/s). Connecting ADC chips together in eight different time domains increases the quantity of samples taken by a factor of eight. This method of interleaving requires that the input signal being sampled is split into eight identical signals and arrives at each ADC chip at the same point in time. The splitting of the input signal is performed in the analog front end containing a wideband filter that impedance matches the input signal to the ADC chips. Each ADC uses a clock to tell it when to perform a conversion. Using eight unique clocks spaced in 45-degree increments is the method used to time shift when each ADC chip performs its conversion. Given that this control clock is a fixed frequency, the clock phase shifting is accomplished by tightly controlling the distance that the clock must travel, resulting in a time delay. The interleaved ADC chips will now generate digital data in eight different time domains. These data are processed inside a field-programmable gate array (FPGA) to move the data back into a single time domain and store it into memory. The FPGA also contains a Nios II processor that provides system control and data retrieval via Ethernet.
Date: May 1, 2012
Partner: UNT Libraries Government Documents Department

Site-Directed Research and Development FY 2012 Annual Report

Description: The reports included in this report are for project activities that occurred from October 2011 through September 2012. These reports describe in detail the discoveries, achievements, and challenges encountered by our talented and enthusiastic principal investigators (PIs). Many of the reports describe R&D efforts that were “successful” in their pursuits and resulted in a positive outcome or technology realization. As we’ve stated before, and continue to stress, in some cases the result is a “negative” finding, for instance a technology is currently impractical or out of reach. This can often be viewed erroneously as a “failure,” but is actually a valid outcome in the pursuit of high-risk research, which often leads to unforeseen new paths of discovery. Either result advances our knowledge and increases our ability to identify solutions and/or likewise avoid costly paths not appropriate for the challenges presented. The SDRD program continues to provide an unfettered mechanism for innovation and development that returns multifold to the NNSS mission. Overall the program is a strong R&D innovation engine, benefited by an enhanced mission, committed resources, and sound competitiveness to yield maximum benefit. The 23 projects described exemplify the creativity and ability of a diverse scientific and engineering talent base. The efforts also showcase an impressive capability and resource that can be brought to find solutions to a broad array of technology needs and applications relevant to the NNSS mission and national security.
Date: April 1, 2013
Partner: UNT Libraries Government Documents Department

Evaluation of Portable X-Ray Fluorescence (XRF) Analyzer for Zirconium-Thickness Measurements

Description: This Technical Evaluation Report provides details of preliminary testing/experiments performed using a handheld X-ray fluorescence analyzer. The analyzer will be utilized in upcoming fuel-foil-rolling optimization studies at the INL. The studies are being performed in support of DOE’s Office of Global Threat Reduction -- Reactor Conversion Subprogram. Details of the equipment used, operating parameters, and measurement results are provided in this report.
Date: September 1, 2013
Creator: Moore, Glenn
Partner: UNT Libraries Government Documents Department

A National Tracking Center for Monitoring Shipments of HEU, MOX, and Spent Nuclear Fuel: How do we implement?

Description: Nuclear material safeguards specialists and instrument developers at US Department of Energy (USDOE) National Laboratories in the United States, sponsored by the National Nuclear Security Administration (NNSA) Office of NA-24, have been developing devices to monitor shipments of UF6 cylinders and other radioactive materials , . Tracking devices are being developed that are capable of monitoring shipments of valuable radioactive materials in real time, using the Global Positioning System (GPS). We envision that such devices will be extremely useful, if not essential, for monitoring the shipment of these important cargoes of nuclear material, including highly-enriched uranium (HEU), mixed plutonium/uranium oxide (MOX), spent nuclear fuel, and, potentially, other large radioactive sources. To ensure nuclear material security and safeguards, it is extremely important to track these materials because they contain so-called “direct-use material” which is material that if diverted and processed could potentially be used to develop clandestine nuclear weapons . Large sources could be used for a dirty bomb also known as a radioactive dispersal device (RDD). For that matter, any interdiction by an adversary regardless of intent demands a rapid response. To make the fullest use of such tracking devices, we propose a National Tracking Center. This paper describes what the attributes of such a center would be and how it could ultimately be the prototype for an International Tracking Center, possibly to be based in Vienna, at the International Atomic Energy Agency (IAEA).
Date: July 1, 2009
Creator: Schanfein, Mark
Partner: UNT Libraries Government Documents Department

IAEA Inspections for Undeclared and Declared Activities: Is a More Robust Approach Needed?

Description: The United States has long supported a strong international safeguards system and for many years has served as the foremost supplier of technology, equipment, and training to the International Atomic Energy Agency (IAEA). In doing so, it drew in many instances on DOE sponsored R&D and training that was directed towards domestic safeguards and then adapted for IAEA purposes. This was relatively straightforward because of the strong overlap between the development of nuclear material accountancy measures needed for both domestic and international purposes. Two factors have emerged that have made this strong reliance on domestic measures less and less able to be a source of support for the IAEA. One is the shift by the IAEA safeguards system towards detecting undeclared activities. The second is the shift of domestic attention away from nuclear material accountancy and towards physical protection. As a result, a gap in US sponsored R&D and training relevant to international safeguards has developed. The NNSA Next Generation Safeguards Initiative and the DOE NA-22 Safeguards R&D program are intended to help fill this gap and, thereby, permit the U.S. to remain as the pre-eminent supplier of technology for international safeguards purposes. In this context, IAEA challenges have been examined from the perspective of detecting the diversion of nuclear material from declared stocks; detecting undeclared production of nuclear material and activities at locations declared under INFCIRC/153; and detecting undeclared nuclear material and activities elsewhere in a state. Of these, the detection of undeclared nuclear material and activities is, perhaps, the IAEA’s most significant challenge. It is a challenge that even the international community finds difficult to meet because of the scope and the geographic scale of the problem, the technical constraints, the knowledge required, and the significant resources needed to deploy effective systems world-wide (e.g., satellite surveillance systems). The ...
Date: July 1, 2009
Creator: Schanfein, Mark
Partner: UNT Libraries Government Documents Department

Science and Technology Challenges for International Safeguards

Description: The science and technology challenges for international safeguards range from cutting edge physics needs to practical technology solutions for high volume data handling and analysis issues. This paper will take a narrow look at some of the predominant challenges, which include those at high throughput commercial facilities and those in the detection of undeclared facilities. It is hoped that by highlighting these areas it can encourage a concerted effort by scientific institutions and industry to provide robust cost-effective solutions.
Date: July 1, 2009
Creator: Schanfein, Mark
Partner: UNT Libraries Government Documents Department

JOINING OF BERYLLIUM-A SURVEY OF THE UNCLASSIFIED LITERATURE

Description: The unclassified literature on the joining of beryllium was surveyed and is summarized. The fields covered are fusion welding, self-welding (diffusion- or pressure-welding), and brazing. The most successful attempts in each field are outlined and other work is referenced. (aauth)
Date: June 1, 1958
Creator: Brown, N.A.
Partner: UNT Libraries Government Documents Department

AN ANNOTATED BIBLIOGRAPHY ON THE EFFECTS OF RADIATION ON HETEROGENEOUSLY CATALYZED REACTIONS AND ON CHEMISORPTION

Description: The 264 references were compiled primarily from a search of Chemical Abstracts, Nuclear Science Abstracts, and Dissertation Abstracts through December 1962. The annotations give the type of radiation, the catalysts investigated, and the test reactions used. The entries are cross-referenced, and indexes of the authors, catalysts, reactions, and type of radiation are provided. The compliation is limited to papers in which either heterogeneously catalyzed reactions, chemisorption, or the radiolysis of adsorbed substances was studied. Papers on the effects of ultraviolet light are not included. (auth)
Date: July 17, 1963
Creator: Krohn, N.A.
Partner: UNT Libraries Government Documents Department

Comparison of Ge(Li) and anti-Compton systems for measurements of environmental samples

Description: There are numerous reasons for performing environmental measurements for routine health or safety monitoring and to determine the movement of trace elements or radionuclides through our environment to man. This is often a requirement for the licensing of nuclear power reactors, as well as many other meteorological or environmental research experiments. In this paper a variety of sensitive low-level counting systems are discussed from an analyst's viewpoint, centering on a variety of Nal(Tl) and Ge(Li) gamma ray spectrometers. The coincident gamma-ray emitters are most sensitively detected through NaI(Tl) multidimensional gamma ray spectrometry, while single gamma ray emitters are very sensitively detected with Ge(Li) detector systems. NaI(Tl) detector systems are superior in general for environmental measurements. (auth)
Date: January 1, 1973
Creator: Wogman, N.A.
Partner: UNT Libraries Government Documents Department

EBT ring physics

Description: This workshop attempted to evaluate the status of the current experimental and theoretical understanding of hot electron ring properties. The dominant physical processes that influence ring formation, scaling, and their optimal behavior are also studied. Separate abstracts were prepared for each of the 27 included papers. (MOW)
Date: April 1, 1980
Creator: Uckan, N.A. (ed.)
Partner: UNT Libraries Government Documents Department

Whispering-mode waveguide

Description: Properties of a relatively new type of waveguide structure of potential use for confining infrared radiation to a small mode volume over long path lengths are reviewed. A single guiding surface with curvature radius rho and band radius R allows propagation of a near-grazing incidence whispering mode of transverse width approx.(lambda ..sqrt..rhoR/..pi..)/sup 1/2/ and radial width approx. 1/2 (lambda/sup 2/R)/sup 1/3. For sufficiently large rho, the loss per revolution for TE mode propagation is approx...pi..A/sub N/, where A/sub N/ is the normal-incidence reflection loss. Results on a number of prototype structures in general agreement with these considerations is described.
Date: January 1, 1981
Creator: Kurnit, N.A.
Partner: UNT Libraries Government Documents Department

Tokamak confinement projections and performance goals

Description: One key quantity to be determined in the design of burning-plasma devices (CIT, ITER, reactors, etc.) is the level of plasma current (I) required to meet the desired plasma performance goals (ignition, high Q, etc.) and device objectives (fusion power, wall loading, current drive power, etc.). It is shown that these goals and objectives can be expressed in terms of the ''figure-of-merit'' parameter IA/sup alpha//R/sup x/(/approximately/f(LB/sup y/), where A is the aspect ratio, R is the major radius, L(= R, a) is the characteristic length, B is the toroidal magnetic field on axis, and the exponents ..cap alpha.. /approximately/ 1 +- 0.5 and x /approximately/ 0-0.5 (y /approximately/ 1-2) depend on the confinement assumptions and operational limits. To reach ignition or high Q, the main goal is to optimize IA/sup alpha//R/sup x/, subject to other engineering design constraints. In a CIT-like device (with R /approximately/ 2 m, kappa /approximately/ 2, q/sub psi/ greater than or equal to 3), the ignition requirements is I(A/3)/sup alpha/ /approximately/ 9-15 MA for ''enhanced'' L-mode (H-mode) confinement scaling expressions; an ITER-like device (with R /approximately/ 5-6 m, kappa /approximately/ 2, q/sub psi/ greater than or equal to 3) would require I(A/3)/sup alpha/ /approximately/ 15-25 MA. These requirements are embodied in the present CIT (with I /approximately/ 11 MA, A /approximately 3.25) and ITER (with I /approximately/ 18-22, A /approximately/ 3.1-2.6) designs. 12 refs., 1 fig., 3 tabs.
Date: January 1, 1988
Creator: Uckan, N.A.
Partner: UNT Libraries Government Documents Department

Physics issues of an EBT reactor

Description: The plasma physics areas that influence the operating characteristics of EBTs are the following: (1) particle orbits, equilibrium, and magnetic; (2) stability boundaries of both core and ring plasmas; (3) transport scaling; (4) heating; and (5) ring-core interaction and power balance. In addition to the conventional mode of EBT operation, innovative ideas that enhance the reactor performance include: (a) the use of supplementary (and/or trim) coils to improve confinement (and/or stability); (b) control of ambipolar potential (and its sign, i.e., positive electric field) to enhance confinement (and to be able to burn alternative fuels, i.e., D-D, etc., in a reasonably sized reactor); and (c) the possibility of fundamental ring mode heating to reduce microwave frequency requirements by a factor of 2. This paper reviews each of these areas briefly and discusses their projections to a reactor.
Date: January 1, 1981
Creator: Uckan, N.A.
Partner: UNT Libraries Government Documents Department

Physics design options for compact ignition experiments

Description: This paper considers the following topics: (1) physics assessments-design and engineering impact, (2) zero-dimensional confinement studies relating to physics requirements and options for ignited plasmas, classes of devices with equivalent performance, and sensitivity to variations in confinement models, and (3) one and one-half dimensional confinement studies relating to dynamic simulations, critical physics issues, startup analyses, and volt-second consumption. (MOW)
Date: January 1, 1985
Creator: Uckan, N.A.
Partner: UNT Libraries Government Documents Department

Resonance production in two-photon interactions

Description: Resonance production in two-photon interactions is studied using data collected with the ASP detector at the PEP e/sup +/e/sup /minus// storage ring located at the Stanford Linear Accelerator Center. The ASP detector is a non-magnetic lead-glass calorimeter constructed from 632 lead-glass bars. It covers 94% of 4..pi.. in solid angle, extending to within 20/degree/ of the beamline. Lead-scintillator calorimeters extend the coverage to within 21 mr of the beamline on both sides. Energy resolution of ..sqrt..E/10%, where E is the energy is GeV, is achieved for electrons and photons in the lead-glass calorimeter, and particle trajectories are reconstructed with high efficiency. A total luminosity of 108 pb/sup /minus/1/ was collected with the ASP detector at a center-of-mass energy of 29 GeV. The observed process is e/sup +/e/sup /minus// ..-->.. e/sup +/e/sup /minus//..gamma..*..gamma..* ..-->.. e/sup +/e/sup /minus//X, is a pseudoscalar resonance (J/sup PC/ = 0/sup /minus/+/) and ..gamma..* is a virtual (mass /ne/ 0) photon. The outgoing electrons scatter down the beampipe and are not detected. The observed resonances are the /eta/ and /eta/' mesons, with masses of 549 and 958 MeV, respectively. They are detected in the ..gamma gamma.. decay mode; a total of 2380 +- 49 /eta/ ..-->.. ..gamma gamma.. and 568 +- 26 /eta/' ..-->.. ..gamma gamma.. events are observed. From the number of events, the detection efficiency, and the calculated production cross sections the radiative widths, GAMMA/sub ..gamma gamma../, of the /eta/ and /eta/' were measured and found to be: GAMMA/sub ..gamma gamma../(/eta/) = .481 +- .010 +- .047keV and GAMMA/sub ..gamma gamma../(/eta/') = 4.71 +- .22 +- .70keV. These results are in good agreement with the world average values. 67 refs., 42 figs., 20 tabs.
Date: February 1, 1989
Creator: Roe, N.A.
Partner: UNT Libraries Government Documents Department