2011 Superconductivity Gordon Research Conference (June 5-10, 2011, Waterville Valley Resort, Waterville Valley, New Hampshire) (open access)

2011 Superconductivity Gordon Research Conference (June 5-10, 2011, Waterville Valley Resort, Waterville Valley, New Hampshire)

The 2011 Gordon Research Conference on Superconductivity will commemorate the 100th anniversary of the discovery of superconductivity by providing a forum for discussion of the latest experimental and theoretical advances in this field. The conference will bring together experts to address the current challenges in understanding correlated superconductors - from cuprates and pnictides to heavy fermion superconductors. The fundamental mechanisms of superconducting pairing, the underlying explanations for thermodynamic phase diagrams including potential importance of competing phases, the correspondence between these phenomena, and the transport and spectroscopic properties of these materials will be among the themes of the conference. We will also discuss the feasibility of using lessons learned from the study of known superconductors as a guide to the future discovery of novel and higher temperature superconductors. Speakers will be strongly encouraged to present new, unpublished work, which will ensure that discussions evoke and explore new research directions. The participation of young scientists at the graduate student or post-doctoral level will be encouraged by the offering of selected presentations, focused discussions with invited speakers, and poster sessions. In addition, the organizers have earmarked funds to facilitate attendance of members of groups underrepresented in science and engineering.
Date: June 10, 2011
Creator: Yazdani, Ali
System: The UNT Digital Library
Adaptive Systems Engineering: A Medical Paradigm for Practicing Systems Engineering (open access)

Adaptive Systems Engineering: A Medical Paradigm for Practicing Systems Engineering

From its inception in the defense and aerospace industries, SE has applied holistic, interdisciplinary tools and work-process to improve the design and management of 'large, complex engineering projects.' The traditional scope of engineering in general embraces the design, development, production, and operation of physical systems, and SE, as originally conceived, falls within that scope. While this 'traditional' view has expanded over the years to embrace wider, more holistic applications, much of the literature and training currently available is still directed almost entirely at addressing the large, complex, NASA and defense-sized systems wherein the 'ideal' practice of SE provides the cradle-to-grave foundation for system development and deployment. Under such scenarios, systems engineers are viewed as an integral part of the system and project life-cycle from conception to decommissioning. In far less 'ideal' applications, SE principles are equally applicable to a growing number of complex systems and projects that need to be 'rescued' from overwhelming challenges that threaten imminent failure. The medical profession provides a unique analogy for this latter concept and offers a useful paradigm for tailoring our 'practice' of SE to address the unexpected dynamics of applying SE in the real world. In short, we can be much more effective …
Date: June 1, 2011
Creator: Hamelin, R. Douglas; Klingler, Ron D. & Dieckmann, Christopher
System: The UNT Digital Library
Advanced simulation capability for environmental management (ASCEM): An overview of initial results (open access)

Advanced simulation capability for environmental management (ASCEM): An overview of initial results

None
Date: June 1, 2011
Creator: Williamson, M.; Meza, J.; Moulton, D.; Gorton, I.; Feshley, M.; Dixon, P. et al.
System: The UNT Digital Library
Advances in Modeling Radiation Dispersal Device and Nuclear Detonation Effects (open access)

Advances in Modeling Radiation Dispersal Device and Nuclear Detonation Effects

None
Date: June 7, 2011
Creator: Nasstrom, J. S.; Foster, K. T.; Goldstein, P.; Dillon, M. B.; Wimer, N. G.; Homann, S. et al.
System: The UNT Digital Library
AFCI-2.0 Library of Neutron Cross Section Covariances (open access)

AFCI-2.0 Library of Neutron Cross Section Covariances

Neutron cross section covariance library has been under development by BNL-LANL collaborative effort over the last three years. The primary purpose of the library is to provide covariances for the Advanced Fuel Cycle Initiative (AFCI) data adjustment project, which is focusing on the needs of fast advanced burner reactors. The covariances refer to central values given in the 2006 release of the U.S. neutron evaluated library ENDF/B-VII. The preliminary version (AFCI-2.0beta) has been completed in October 2010 and made available to the users for comments. In the final 2.0 release, covariances for a few materials were updated, in particular new LANL evaluations for {sup 238,240}Pu and {sup 241}Am were adopted. BNL was responsible for covariances for structural materials and fission products, management of the library and coordination of the work, while LANL was in charge of covariances for light nuclei and for actinides.
Date: June 26, 2011
Creator: Herman, M.; Herman, M.; Oblozinsky, P.; Mattoon, C.; Pigni, M.; Hoblit, S. et al.
System: The UNT Digital Library
Analysis of Minimum Efficiency Performance Standards for Residential General Service Lighting in Chile (open access)

Analysis of Minimum Efficiency Performance Standards for Residential General Service Lighting in Chile

Minimum Efficiency Performance Standards (MEPS) have been chosen as part of Chile's national energy efficiency action plan. As a first MEPS, the Ministry of Energy has decided to focus on a regulation for lighting that would ban the sale of inefficient bulbs, effectively phasing out the use of incandescent lamps. Following major economies such as the US (EISA, 2007) , the EU (Ecodesign, 2009) and Australia (AS/NZS, 2008) who planned a phase out based on minimum efficacy requirements, the Ministry of Energy has undertaken the impact analysis of a MEPS on the residential lighting sector. Fundacion Chile (FC) and Lawrence Berkeley National Laboratory (LBNL) collaborated with the Ministry of Energy and the National Energy Efficiency Program (Programa Pais de Eficiencia Energetica, or PPEE) in order to produce a techno-economic analysis of this future policy measure. LBNL has developed for CLASP (CLASP, 2007) a spreadsheet tool called the Policy Analysis Modeling System (PAMS) that allows for evaluation of costs and benefits at the consumer level but also a wide range of impacts at the national level, such as energy savings, net present value of savings, greenhouse gas (CO2) emission reductions and avoided capacity generation due to a specific policy. Because historically …
Date: June 1, 2011
Creator: Letschert, Virginie E.; McNeil, Michael A.; Leiva Ibanez, Francisco Humberto; Ruiz, Ana Maria; Pavon, Mariana & Hall, Stephen
System: The UNT Digital Library
Analysis of the ANL Test Method for 6CVS Containment Vessels (open access)

Analysis of the ANL Test Method for 6CVS Containment Vessels

In the fall of 2010, Argonne National Laboratory (ANL) contracted with vendors to design and build 6CVS containment vessels as part of their effort to ship Fuel Derived Mixed Fission Product material. The 6CVS design is based on the Savannah River National Laboratory's (SRNL) design for 9975 and 9977 six inch diameter containment vessels. The main difference between the designs is that the 6CVS credits the inner O-ring seal as the containment boundary while the SRNL design credits the outer O-ring seal. Since the leak test must be done with the inner O-ring in place, the containment vessel does not have a pathway for getting the helium into the vessel during the leak test. The leak testing contractor was not able to get acceptable leak rates with the specified O-ring, but they were able to pass the leak test with a slightly larger O-ring. ANL asked the SRNL to duplicate the leak test vendor's method to determine the cause of the high leak rates. The SRNL testing showed that the helium leak indications were caused by residual helium left within the 6CVS Closure Assembly by the leak test technique, and by helium permeation through the Viton O-ring seals. After SRNL …
Date: June 6, 2011
Creator: Trapp, D. & Crow, G.
System: The UNT Digital Library
Annealing to Mitigate Pitting in Electropolished Niobium Coupons and SRF Cavities (open access)

Annealing to Mitigate Pitting in Electropolished Niobium Coupons and SRF Cavities

Ongoing studies at Fermilab investigate whether dislocations and other factors instigate pitting during cavity electropolishing (EP), despite careful processing controls and the inherent leveling mechanism of EP itself. Here, cold-worked niobium coupons, which exhibited increased tendencies for pitting in our past study, were annealed in a high vacuum furnace and subsequently processed by EP. Laser confocal scanning microscopy and special defect counting algorithms were used to assess the population of pits formed. Hardness measurements indicated that annealing for 2 hours at 800 C produced recovery, whereas annealing for 12 hours at 600 C did not, as is consistent with known changes for cavities annealed in a similar way. The 800 C anneal was effective in some cases but not others, and we discuss reasons why tendencies for pitting remain. We discuss implications for cavities and continued work to understand pitting.
Date: June 8, 2011
Creator: Cooley, L. D.; Hahn, E.; Hicks, D.; Romanenko, A.; Schuessler, R. & Thompson, C.
System: The UNT Digital Library
Annomolous Elevated Radiocarbon Measurements of PM2.5 (open access)

Annomolous Elevated Radiocarbon Measurements of PM2.5

None
Date: June 1, 2011
Creator: Buchholz, B. A.; Fallon, S.; Zermeno, P.; Bench, G. & Schichtel, B. A.
System: The UNT Digital Library
Antenna Splitting Functions for Massive Particles (open access)

Antenna Splitting Functions for Massive Particles

An antenna shower is a parton shower in which the basic move is a color-coherent 2 {yields} 3 parton splitting process. In this paper, we give compact forms for the spin-dependent antenna splitting functions involving massive partons of spin 0 and spin 1/2. We hope that this formalism we have presented will be useful in describing the QCD dynamics of the top quark and other heavy particles at LHC.
Date: June 22, 2011
Creator: Larkoski, Andrew J. & Peskin, Michael E.
System: The UNT Digital Library
Application of Cryocoolers to a Vintage Dilution Refrigerator (open access)

Application of Cryocoolers to a Vintage Dilution Refrigerator

A dilution refrigerator is required for 50mK detector operation of CDMS (Cryogenic Dark Matter Search). Besides shielding the dilution refrigerator itself, the liquid nitrogen shield and liquid helium bath in the refrigerator cool the detector cryostat heat shields and cool electronics, resulting in significant external heat loads at 80K and at 4K. An Oxford Instruments Kelvinox 400 has served this role for ten years but required daily transfers of liquid nitrogen and liquid helium. Complicating the cryogen supply is the location 800 meters below ground in an RF shielded, class 10000 clean room at Soudan, MN. Nitrogen and helium re-liquefiers using cryocoolers were installed outside the clean room and continuously condense room temperature gas and return the liquids to the dilution refrigerator through a transfer line. This paper will describe the design, installation, controls and performance of liquefaction systems.
Date: June 6, 2011
Creator: Schmitt, Richard; Smith, Gary; Ruschman, Mark & Beaty, Jim
System: The UNT Digital Library
Application of the INSTANT-HPS PN Transport Code to the C5G7 Benchmark Problem (open access)

Application of the INSTANT-HPS PN Transport Code to the C5G7 Benchmark Problem

INSTANT is the INL's next generation neutron transport solver to support high-fidelity multi-physics reactor simulation INSTANT is in continuous development to extend its capability Code is designed to take full advantage of middle to large cluster (10-1000 processors) Code is designed to focus on method adaptation while also mesh adaptation will be possible. It utilizes the most modern computing techniques to generate a neutronics tool of full-core transport calculations for reactor analysis and design. It can perform calculations on unstructured 2D/3D triangular, hexagonal and Cartesian geometries. Calculations can be easily extended to more geometries because of the independent mesh framework coded with the model Fortran. This code has a multigroup solver with thermal rebalance and Chebyshev acceleration. It employs second-order PN and Hybrid Finite Element method (PNHFEM) discretization scheme. Three different in-group solvers - preconditioned Conjugate Gradient (CG) method, preconditioned Generalized Minimal Residual Method (GMRES) and Red-Black iteration - have been implemented and parallelized with the spatial domain decomposition in the code. The input is managed with extensible markup language (XML) format. 3D variables including the flux distributions are outputted into VTK files, which can be visualized by tools such as VisIt and ParaView. An extension of the code named …
Date: June 1, 2011
Creator: Wang, Y.; Zhang, H.; Szilard, R. H. & Martineau, R. C.
System: The UNT Digital Library
Application of Triple Coincidence for the Detection of Small Amounts of Special Nuclear Materials (open access)

Application of Triple Coincidence for the Detection of Small Amounts of Special Nuclear Materials

We constructed a device that measures two {gamma}-rays and one neutron from spontaneous fission and any resulting multiplication chains. It extends the associated particle technique based upon correlated counting of the multiplicity of gamma-rays and neutrons released in spontaneous- or neutron-induced fission. There are two advantages in incorporating a third detector in the design over the standard two-detector version. First, we found that random uncorrelated events dominate the background of coincident counting with a gamma-ray- and neutron-detector. These might be suppressed by requiring an additional coincidence. Second, the time history of gamma-ray emission between the two gamma-ray detectors is related to multiplication in the target media. Multiplication in highly enriched uranium is much greater than in depleted uranium.
Date: June 12, 2011
Creator: DIOSZEGI, I.; Salwen, C. & and Forman, L.
System: The UNT Digital Library
Approaching the Island of Inversion: 34P (open access)

Approaching the Island of Inversion: 34P

Yrast states in 34P were investigated using the 18O(18O,pn) reaction at energies of 20, 24, 25, 30, and 44 MeV at Florida State University and at Lawrence Berkeley National Laboratory. The level scheme was expanded, ray angular distributions were measured, and lifetimes were inferred with the Doppler-shift attenuation method by detecting decay protons in coincidence with one or more rays. The results provide a clearer picture of the evolution of structure approaching the 'Island of Inversion', particularly how the 1 and 2 particle-hole (ph) states fall in energy with increasing neutro number approaching inversion. However, the agreement of the lowest few states with pure sd shell model predictions shows that the level scheme of 34P is not itself inverted. Rather, the accumulated evidence indicates that the 1-ph states start at 2.3 MeV. A good candidate for the lowest 2-ph state lies at 6236 keV, just below the neutron separation energy of 6291 keV. Shell model calculations made using a small modification of the WBP interaction reproduce the negative-parity, 1-ph states rather well.
Date: June 14, 2011
Creator: Bender, P. C.; Hoffman, C. R.; Wiedeking, M.; Allmond, J. M.; Bernstein, L. A.; Burke, J. T. et al.
System: The UNT Digital Library
ARPES Studies of Cuprate Fermiology: Superconductivity, Pseudogap and Quasiparticle Dynamics (open access)

ARPES Studies of Cuprate Fermiology: Superconductivity, Pseudogap and Quasiparticle Dynamics

We present angle-resolved photoemission spectroscopy (ARPES) studies of the cuprate high-temperature superconductors which elucidate the relation between superconductivity and the pseudogap and highlight low-energy quasiparticle dynamics in the superconducting state. Our experiments suggest that the pseudogap and superconducting gap represent distinct states, which coexist below T{sub c}. Studies on Bi-2212 demonstrate that the near-nodal and near-antinodal regions behave differently as a function of temperature and doping, implying that different orders dominate in different momentum-space regions. However, the ubiquity of sharp quasiparticles all around the Fermi surface in Bi-2212 indicates that superconductivity extends into the momentum-space region dominated by the pseudogap, revealing subtlety in this dichotomy. In Bi-2201, the temperature dependence of antinodal spectra reveals particle-hole asymmetry and anomalous spectral broadening, which may constrain the explanation for the pseudogap. Recognizing that electron-boson coupling is an important aspect of cuprate physics, we close with a discussion of the multiple 'kinks' in the nodal dispersion. Understanding these may be important to establishing which excitations are important to superconductivity.
Date: June 23, 2011
Creator: Vishik, Inna
System: The UNT Digital Library
Assessment of Decay and Storage Area for Activated Materials in the National Ignition Facility (open access)

Assessment of Decay and Storage Area for Activated Materials in the National Ignition Facility

None
Date: June 3, 2011
Creator: Khater, H.; Brereton, S.; Dauffy, L.; Hall, J.; Hansen, L.; Kim, S. et al.
System: The UNT Digital Library
Assessment of Nuclear Resonance Fluorescence for Spent Nuclear Fuel Assay (open access)

Assessment of Nuclear Resonance Fluorescence for Spent Nuclear Fuel Assay

In nuclear resonance fluorescence (NRF) measurements, resonances are excited by an external photon beam leading to the emission of gamma rays with specific energies that are characteristic of the emitting isotope. NRF promises the unique capability of directly quantifying a specific isotope without the need for unfolding the combined responses of several fissile isotopes as is required in other measurement techniques. We have analyzed the potential of NRF as a non-destructive analysis technique for quantitative measurements of Pu isotopes in spent nuclear fuel (SNF). Given the low concentrations of 239Pu in SNF and its small integrated NRF cross sections, the main challenge in achieving precise and accurate measurements lies in accruing sufficient counting statistics in a reasonable measurement time. Using analytical modeling, and simulations with the radiation transport code MCNPX that has been experimentally tested recently, the backscatter and transmission methods were quantitatively studied for differing photon sources and radiation detector types. Resonant photon count rates and measurement times were estimated for a range of photon source and detection parameters, which were used to determine photon source and gamma-ray detector requirements. The results indicate that systems based on a bremsstrahlung source and present detector technology are not practical for high-precision …
Date: June 30, 2011
Creator: Quiter, Brian; Ludewigt, Bernhard & Ambers, Scott
System: The UNT Digital Library
Assisting the Government of Iraq in Implementing the Additional Protocol (open access)

Assisting the Government of Iraq in Implementing the Additional Protocol

None
Date: June 30, 2011
Creator: Essner, J
System: The UNT Digital Library
ATOMIC FORCE LITHOGRAPHY OF NANO MICROFLUIDIC CHANNELS FOR VERIFICATION AND MONITORING IN AQUEOUS SOLUTIONS (open access)

ATOMIC FORCE LITHOGRAPHY OF NANO MICROFLUIDIC CHANNELS FOR VERIFICATION AND MONITORING IN AQUEOUS SOLUTIONS

The growing interest in the physics of fluidic flow in nanoscale channels, as well as the possibility for high sensitive detection of ions and single molecules is driving the development of nanofluidic channels. The enrichment of charged analytes due to electric field-controlled flow and surface charge/dipole interactions along the channel can lead to enhancement of sensitivity and limits-of-detection in sensor instruments. Nuclear material processing, waste remediation, and nuclear non-proliferation applications can greatly benefit from this capability. Atomic force microscopy (AFM) provides a low-cost alternative for the machining of disposable nanochannels. The small AFM tip diameter (< 10 nm) can provide for features at scales restricted in conventional optical and electron-beam lithography. This work presents preliminary results on the fabrication of nano/microfluidic channels on polymer films deposited on quartz substrates by AFM lithography.
Date: June 9, 2011
Creator: Torres, R.; Mendez-Torres, A. & Lam, P.
System: The UNT Digital Library
Benefits and Costs of Improved IEQ in U.S. Offices (open access)

Benefits and Costs of Improved IEQ in U.S. Offices

This paper estimates some of the benefits and costs of implementing scenarios that improve indoor environmental quality (IEQ) in the stock of U.S. office buildings. The scenarios include increasing ventilation rates when they are below 10 or 15 L/s per person, adding outdoor-air economizers and controls when absent, eliminating winter indoor temperatures greater than 23 oC, and reducing dampness and mold problems. The estimated benefits of the scenarios analyzed are substantial in magnitude, including increased work performance, reduced sick building syndrome symptoms, reduced absence, and improved thermal comfort for millions of office workers. The combined potential annual economic benefit of a set ofnon-overlapping scenarios is approximately $20 billion. While the quantitative estimates have a high uncertainty, the opportunity for substantial benefits is clear. Some IEQ improvement measures will save energy while improving health or productivity, and implementing these measures should be the highest priority.
Date: June 1, 2011
Creator: Fisk, William J.; Black, Douglas & Brunner, Gregory
System: The UNT Digital Library
Building a Better mSUGRA: WIMP Dark Matter Without Flavor Violation (open access)

Building a Better mSUGRA: WIMP Dark Matter Without Flavor Violation

None
Date: June 20, 2011
Creator: Craig, Nathaniel J.; /Stanford U., Phys. Dept.; Green, Daniel & /SLAC /Stanford U., Phys. Dept.
System: The UNT Digital Library
CHARACTERIZATION OF PD IMPURITIES AND TWIN BOUNDARY DEFECTS IN DETECTOR GRADE CDZNTE CRYSTALS (open access)

CHARACTERIZATION OF PD IMPURITIES AND TWIN BOUNDARY DEFECTS IN DETECTOR GRADE CDZNTE CRYSTALS

Synthetic CdZnTe or ''CZT'' crystals are highly suitable for {gamma}-spectrometers operating at the room temperature. Secondary phases (SP) in CZT are known to inhibit detector performance, particularly when they are present in large numbers or dimensions. These SP may exist as voids or composites of non-cubic phase metallic Te layers with bodies of polycrystalline and amorphous CZT material and voids. Defects associated with crystal twining may also influence detector performance in CZT. Using transmission electron microscopy, we identify two types of defects that are on the nano scale. The first defect consists of 40 nm diameter metallic Pd/Te bodies on the grain boundaries of Te-rich composites. Although the nano-Pd/Te bodies around these composites may be unique to the growth source of this CZT material, noble metal impurities like these may contribute to SP formation in CZT. The second defect type consists of atom-scale grain boundary dislocations. Specifically, these involve inclined ''finite-sized'' planar defects or interfaces between layers of atoms that are associated with twins. Finite-sized twins may be responsible for the subtle but observable striations that can be seen with optical birefringence imaging and synchrotron X-ray topographic imaging.
Date: June 22, 2011
Creator: Duff, M.
System: The UNT Digital Library
Characterization Of The Hydrogenation Products Of Bix (phenylethynyl) Benzene (DEB) Getter Using Combined GC/FTIR/MS, FT-Raman, and ATR Spectroscopies (U) (open access)

Characterization Of The Hydrogenation Products Of Bix (phenylethynyl) Benzene (DEB) Getter Using Combined GC/FTIR/MS, FT-Raman, and ATR Spectroscopies (U)

Organic hydrogen getters are utilized to minimize hydrogen accumulation in sealed systems where such build up could produce either a safety problem from pressure build up or corrosion problem due the hydriding of metals contained in the sealed vessel. DEB (1,4 bis (phenyl ethynyl) benzene) is a hydrogen getter that is based on the palladium catalyzed hydrogenation of triple bonds to single bonds in aromatic aryl compound. DEB is a getter mixed with 25% carbon and 1% Pd and pressed into pellets with some porosity. The reaction mechanisms are complex involving solid state reactions with a heterogeneous catalyst leading to the many intermediates.
Date: June 9, 2011
Creator: Smyrl, N. R. & Powell, G. L.
System: The UNT Digital Library
Characterization of Uranium Oxyfluoride Particles for Nuclear Safeguards (open access)

Characterization of Uranium Oxyfluoride Particles for Nuclear Safeguards

None
Date: June 15, 2011
Creator: Kips, R.; Kristo, M. J.; Crowhurst, J. & Hutcheon, I. D.
System: The UNT Digital Library