A METHODOLOGY FOR DETERMINING THE DOSE RATE FOR BOUNDING MASS LIMITS IN A 9977 PACKAGING (open access)

A METHODOLOGY FOR DETERMINING THE DOSE RATE FOR BOUNDING MASS LIMITS IN A 9977 PACKAGING

The Small Gram Quantity (SGQ) concept is based on the understanding that the hazards associated with the shipment of a radioactive material are directly proportional to its mass. This study describes a methodology that estimates the acceptable masses for several neutron and gamma emitting isotopes that can be shipped in a 9977 Package compliant with the Title 10 of the Code of Federal Regulations, Part 71 (10CFR71) external radiation level limits. 10CFR71.33 states that a shipping application identifies the radioactive and fissile materials at their maximum quantity and provides an evaluation demonstrating compliance with the external radiation standards. Since rather small amounts of some isotopes emit sufficiently strong radiation to produce a large external dose rate, quantifying of the dose rate for a proposed content is a challenging issue for the SGQ approach. It is essential to quantify external radiation levels from several common gamma and neutron sources that can be safely placed in a specific packaging, to ensure compliance with federal regulations. A methodology was established for determining the dose rate for bounding mass limits for a set of isotopes in the Model 9977 Shipping Package. Calculations were performed to estimate external radiation levels using the MCNP radiation transport …
Date: May 24, 2012
Creator: Abramczyk, G.; Bellamy, S.; Nathan, S. & Loftin, B.
System: The UNT Digital Library
Femtosecond Synchronization of Laser Systems for the LCLS (open access)

Femtosecond Synchronization of Laser Systems for the LCLS

The scientific potential of femtosecond x-ray pulses at linac-driven free-electron lasers such as the Linac Coherent Light Source is tremendous. Time-resolved pump-probe experiments require a measure of the relative arrival time of each x-ray pulse with respect to the experimental pump laser. An optical timing system based on stabilized fiber links has been developed for the LCLS to provide this synchronization. Preliminary results show synchronization of the installed stabilized links at the sub-20-femtosecond level. We present details of the implementation at LCLS and potential for future development.
Date: August 24, 2012
Creator: Byrd, John; Doolittle, Lawrence; Huang, Gang; Staples, John; Wilcox, Russell; Arthur, John et al.
System: The UNT Digital Library
Geochemical and Strontium Isotope Characterization of Produced Waters from Marcellus Shale Natural Gas Extraction (open access)

Geochemical and Strontium Isotope Characterization of Produced Waters from Marcellus Shale Natural Gas Extraction

Extraction of natural gas by hydraulic fracturing of the Middle Devonian Marcellus Shale, a major gas-bearing unit in the Appalachian Basin, results in significant quantities of produced water containing high total dissolved solids (TDS). We carried out a strontium (Sr) isotope investigation to determine the utility of Sr isotopes in identifying and quantifying the interaction of Marcellus Formation produced waters with other waters in the Appalachian Basin in the event of an accidental release, and to provide information about the source of the dissolved solids. Strontium isotopic ratios of Marcellus produced waters collected over a geographic range of ∼375 km from southwestern to northeastern Pennsylvania define a relatively narrow set of values (εSr SW = +13.8 to +41.6, where εSr SW is the deviation of the 87Sr/86Sr ratio from that of seawater in parts per 104); this isotopic range falls above that of Middle Devonian seawater, and is distinct from most western Pennsylvania acid mine drainage and Upper Devonian Venango Group oil and gas brines. The uniformity of the isotope ratios suggests a basin-wide source of dissolved solids with a component that is more radiogenic than seawater. Mixing models indicate that Sr isotope ratios can be used to sensitively differentiate …
Date: February 24, 2012
Creator: Chapman, Elizabeth C.; Capo, Rosemary. C.; Stewart, Brian W.; Kirby, Carl S.; Hammack, Richard W.; Schroeder, Karl T. et al.
System: The UNT Digital Library
Photonic Doppler Velocimetry Multiplexing Techniques: Evaluation of Photonic Techniques (open access)

Photonic Doppler Velocimetry Multiplexing Techniques: Evaluation of Photonic Techniques

This poster reports progress related to photonic technologies. Specifically, the authors developed diagnostic system architecture for a Multiplexed Photonic Doppler Velocimetry (MPDV) that incorporates frequency and time-division multiplexing into existing PDV methodology to provide increased channel count. Current MPDV design increases number of data records per digitizer channel 8x, and also operates as a laser-safe (Class 3a) system. Further, they applied heterodyne interferometry to allow for direction-of-travel determination and enable high-velocity measurements (>10 km/s) via optical downshifting. They also leveraged commercially available, inexpensive and robust components originally developed for telecom applications. Proposed MPDV architectures employ only commercially available, fiber-coupled hardware.
Date: May 24, 2012
Creator: Daykin, Edward
System: The UNT Digital Library
The First Angstrom X-Ray Free-Electron Laser (open access)

The First Angstrom X-Ray Free-Electron Laser

The Linac Coherent Light Source produced its first x-ray laser beam on 10 April 2009. Today it is routinely producing x-ray pulses with energy >2 mJ across the operating range from 820-8,200 eV. The facility has begun operating for atomic/molecular/optical science experiments. Performance of the facility in its first user run (1 October - 21 December) and current machine development activities will be presented. Early results from the preparations for the start of the second user run is also reported.
Date: August 24, 2012
Creator: Galayda, John
System: The UNT Digital Library
Status Update of the Power Conditioning System in the National Ignition Facility (open access)

Status Update of the Power Conditioning System in the National Ignition Facility

None
Date: May 24, 2012
Creator: Galloudec, B. L.; Arnold, P.; James, G.; Pendleton, D.; Petersen, D.; Arellano-Womack, G. et al.
System: The UNT Digital Library
Prompt Neutron Lifetime for the NBSR Reactor (open access)

Prompt Neutron Lifetime for the NBSR Reactor

In preparation for the proposed conversion of the National Institute of Standards and Technology (NIST) research reactor (NBSR) from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel, certain point kinetics parameters must be calculated. We report here values of the prompt neutron lifetime that have been calculated using three independent methods. All three sets of calculations demonstrate that the prompt neutron lifetime is shorter for the LEU fuel when compared to the HEU fuel and longer for the equilibrium end-of-cycle (EOC) condition when compared to the equilibrium startup (SU) condition for both the HEU and LEU fuels.
Date: June 24, 2012
Creator: Hanson, A. L. & Diamond, D.
System: The UNT Digital Library
High Multiplicity Searches at the LHC Using Jet Masses (open access)

High Multiplicity Searches at the LHC Using Jet Masses

This article introduces a new class of searches for physics beyond the Standard Model that improves the sensitivity to signals with high jet multiplicity. The proposed searches gain access to high multiplicity signals by reclustering events into large-radius, or 'fat', jets and by requiring that each event has multiple massive jets. This technique is applied to supersymmetric scenarios in which gluinos are pair-produced and then subsequently decay to final states with either moderate quantities of missing energy or final states without missing energy. In each of these scenarios, the use of jet mass improves the estimated reach in gluino mass by 20% to 50% over current LHC searches.
Date: April 24, 2012
Creator: Hook, Anson; /SLAC /Stanford U., Appl. Phys. Dept.; Izaguirre, Eder; /SLAC /Stanford U., Phys. Dept.; Lisanti, Mariangela; U., /Princeton et al.
System: The UNT Digital Library
Detection of Coherent Structures in Extreme-Scale Simulations (open access)

Detection of Coherent Structures in Extreme-Scale Simulations

The analysis of coherent structures is a common problem in many scientific domains ranging from astrophysics to combustion, fusion, and materials science. The data from three-dimensional simulations are analyzed to detect the structures, extract statistics on them, and track them over time to gain insights into the phenomenon being modeled. This analysis is typically done off-line, using data that have been written out by the simulations. However, the move towards extreme scale architectures, with multi-core processors and graphical processing units, will affect how such analysis is done as it is unlikely that the systems will support the I/O bandwidth required for off-line analysis. Moving the analysis in-situ is a solution only if we know a priori what analysis will be done, as well as the algorithms used and their parameter settings. Even then, we need to ensure that this will not substantially increase the memory requirements or the data movement as the former will be limited and the latter will be expensive. In the Exa-DM project, a collaboration between Lawrence Livermore National Laboratory and University of Minnesota, we are exploring ways in which we can address the conflicting demands of coherent structure analysis of simulation data and the architecture of …
Date: March 24, 2012
Creator: Kamath, C.; Iverson, J.; Kirk, R. & Karypis, G.
System: The UNT Digital Library
2012 ROCK DEFORMATION: FEEDBACK PROCESSES IN ROCK DEFORMATION GORDON RESEARCH CONFERENCE, AUGUST 19-24, 2012 (open access)

2012 ROCK DEFORMATION: FEEDBACK PROCESSES IN ROCK DEFORMATION GORDON RESEARCH CONFERENCE, AUGUST 19-24, 2012

Topics covered include: Failure At High Confining Pressure; Fluid-assisted Slip, Earthquakes & Fracture; Reaction-driven Cracking; Fluid Transport, Deformation And Reaction; Localized Fluid Transport And Deformation; Earthquake Mechanisms; Subduction Zone Dynamics And Crustal Growth.
Date: August 24, 2012
Creator: Kelemen, Peter
System: The UNT Digital Library
Systematic Studies of Light Neutron-Rich Nuclei produced via the Fragmentation of 40Ar (open access)

Systematic Studies of Light Neutron-Rich Nuclei produced via the Fragmentation of 40Ar

None
Date: February 24, 2012
Creator: Kwan, E; Morrissey, D J; Davies, D A; Steiner, M; Sumithrarachchi, C S & Weissman, L
System: The UNT Digital Library
Rapid Determination Of Radiostrontium In Large Soil Samples (open access)

Rapid Determination Of Radiostrontium In Large Soil Samples

A new method for the determination of radiostrontium in large soil samples has been developed at the Savannah River Environmental Laboratory (Aiken, SC, USA) that allows rapid preconcentration and separation of strontium in large soil samples for the measurement of strontium isotopes by gas flow proportional counting. The need for rapid analyses in the event of a Radiological Dispersive Device (RDD) or Improvised Nuclear Device (IND) event is well-known. In addition, the recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid analyses for radionuclides in environmental samples in the event of a nuclear accident. The method employs a novel pre-concentration step that utilizes an iron hydroxide precipitation (enhanced with calcium phosphate) followed by a final calcium fluoride precipitation to remove silicates and other matrix components. The pre-concentration steps, in combination with a rapid Sr Resin separation using vacuum box technology, allow very large soil samples to be analyzed for {sup 89,90}Sr using gas flow proportional counting with a lower method detection limit. The calcium fluoride precipitation eliminates column flow problems typically associated with large amounts of silicates in large soil samples.
Date: May 24, 2012
Creator: Maxwell, Sherrod L.; Culligan, Brian K. & Shaw, Patrick J.
System: The UNT Digital Library
ENHANCED SAFEGUARDS: THE ROLE OF SMART FUNCTIONAL COATINGS FOR TAMPER INDICATION (open access)

ENHANCED SAFEGUARDS: THE ROLE OF SMART FUNCTIONAL COATINGS FOR TAMPER INDICATION

This work investigates the synthesis of smart functional coatings (SFC) using chemical solution deposition methods. Chemical solution deposition methods have recently received attention in the materials research community due to several unique advantages that include low temperature processing, high homogeneity of final products, the ability to fabricate materials with controlled surface properties and pore structures, and the ease of dopant incorporation in controlled concentrations. The optical properties of thin films were investigated using UV-Vis spectroscopy, Raman, SEM and EDS, with the aim of developing a protective transparent coating for a ceramic surface as a first line of defense for tamper indication. The signature produced by the addition of rare earth dopants will be employed as an additional tamper indicating feature. The integration of SFC's as part of a broader verification system such as an electronic seals can provide additional functionality and defense in depth. SFC's can improve the timeliness of detection by providing a robust, in-situ verifiable tamper indication framework.
Date: February 24, 2012
Creator: Mendez-Torres, A.; Martinez-Rodriguez, M.; Brinkman, K. & Krementz, D.
System: The UNT Digital Library
Low-temperature triple-alpha rate in a full three-body model (open access)

Low-temperature triple-alpha rate in a full three-body model

None
Date: May 24, 2012
Creator: Nguyen, N. B.; Nunes, F. M.; Thompson, I. J. & Brown, E. F.
System: The UNT Digital Library
Quasi-isentropic drive development for peak pressures > 10 Mbar (open access)

Quasi-isentropic drive development for peak pressures > 10 Mbar

None
Date: October 24, 2012
Creator: Prisbrey, S. T.; Park, H. S.; Remington, B. A.; May, M.; Cavallo, R.; Comley, A. et al.
System: The UNT Digital Library
An embedded mesh method in a multiple material ALE (open access)

An embedded mesh method in a multiple material ALE

None
Date: February 24, 2012
Creator: Puso, M. A.; Sanders, J.; Settgast, R. & Liu, B.
System: The UNT Digital Library
No-Core Shell Model Analysis Of Light Nuclei (open access)

No-Core Shell Model Analysis Of Light Nuclei

None
Date: September 24, 2012
Creator: Quaglioni, S; Navratil, P; Hupin, G; Langhammee, J; Romero-Redondo, C & Roth, R
System: The UNT Digital Library
LSST Camera Optics Design (open access)

LSST Camera Optics Design

The Large Synoptic Survey Telescope (LSST) uses a novel, three-mirror, telescope design feeding a camera system that includes a set of broad-band filters and three refractive corrector lenses to produce a flat field at the focal plane with a wide field of view. Optical design of the camera lenses and filters is integrated in with the optical design of telescope mirrors to optimize performance. We discuss the rationale for the LSST camera optics design, describe the methodology for fabricating, coating, mounting and testing the lenses and filters, and present the results of detailed analyses demonstrating that the camera optics will meet their performance goals.
Date: May 24, 2012
Creator: Riot, V. J.; Olivier, S.; Bauman, B.; Pratuch, S.; Seppala, L.; Gilmore, D. et al.
System: The UNT Digital Library
Coupling Impedance of a Periodic Array of Diaphragms (Erratum) (open access)

Coupling Impedance of a Periodic Array of Diaphragms (Erratum)

A method is presented for calculating the high-frequency longitudinal and transverse coupling impedances in a periodic array of diaphragms in a circular perfectly conducting pipe. The method is based on Weinstein's theory of diffraction of a plane electromagnetic wave on a stack of halfplanes. Using Weinstein's solution, it is shown that the problem of finding the beam field in the pipe reduces to an effective boundary condition at the radius of the diaphragms that couples the longitudinal electric field with the azimuthal magnetic one. Solving Maxwell's equations with this boundary condition leads to simple formulae for Z{sub long} and Z{sub tr}. A good agreement with a numerical solution of the problem found by other authors is demonstrated.
Date: May 24, 2012
Creator: Stupakov, G. V.
System: The UNT Digital Library
Electron Beam Polarization Measurement Using Touschek Lifetime Technique (open access)

Electron Beam Polarization Measurement Using Touschek Lifetime Technique

Electron beam loss due to intra-beam scattering, the Touschek effect, in a storage ring depends on the electron beam polarization. The polarization of an electron beam can be determined from the difference in the Touschek lifetime compared with an unpolarized beam. In this paper, we report on a systematic experimental procedure recently developed at Duke FEL laboratory to study the radiative polarization of a stored electron beam. Using this technique, we have successfully observed the radiative polarization build-up of an electron beam in the Duke storage ring, and determined the equilibrium degree of polarization and the time constant of the polarization build-up process.
Date: August 24, 2012
Creator: Sun, Changchun; Li, Jingyi; Mikhailov, Stepan; Popov, Victor; Wu, Wenzhong; Wu, Ying et al.
System: The UNT Digital Library
Determination of the 242Pu Branching Ratio via Alpha-Gamma Coincidence (open access)

Determination of the 242Pu Branching Ratio via Alpha-Gamma Coincidence

When the burn-up is high, the {sup 242}Pu isotopic content becomes more important. The traditional correlation method will fail. The {sup 242}Pu isotopic content in the sample plays an essential role if the neutron coincidence method is used to quantify the total amount of plutonium. In one of the earlier measurements we had a chance to measure an isotopic pure (> 99.95 %) {sup 242}Pu thick sample and realized that the difference in the branching ratio (BR) value among current nuclear data3) for the two important gamma-rays at 103.5-keV and 158.8-keV. In this study, the thick sample was counted on a 15% ORTEC safeguards type HPGe to further improve BR determination of the 159-keV gamma-ray. Furthermore, we have made a thin {sup 242}Pu sample from the thick sample and performed alpha-gamma coincidence measurements. Our preliminary gamma-ray BR results are 4.37(6) E-4, 2.79(8) E-5, and 2.25(8) E-6 for 44.9-keV, 103.5-keV, and 158.9-keV, respectively.
Date: May 24, 2012
Creator: Wang, T. F.
System: The UNT Digital Library
PEP-II Status and Outlook (open access)

PEP-II Status and Outlook

PEP-II/BABAR are presently in their second physics run. With machine and detector performance and reliability at an all-time high, almost 51 fb{sup -1} have been integrated by BABAR up to mid-October 2001. PEP-II luminosity has reached 4.4 x 10{sup 33} cm{sup -2} s{sup -1} and our highest monthly delivered luminosity has been above 6 pb{sup -1}, exceeding the performance parameters given in the PEP-II CDR by almost 50%. The increase compared to the first run in 2000 has been achieved by a combination of beam-current increase and beam-size decrease. In this paper we will summarize the PEP-II performance and the present limitations as well as our plans to further increase machine performance.
Date: April 24, 2012
Creator: Wienands, H. U.; Biagini, M. E.; Decker, F. J.; Donald, M. H.; Ecklund, S.; Fisher, A. et al.
System: The UNT Digital Library
Minimizing Artifacts in Analysis of Surface Statistics (open access)

Minimizing Artifacts in Analysis of Surface Statistics

N/A
Date: June 24, 2012
Creator: Z., Takacs P.
System: The UNT Digital Library