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Methods for fabricating arrays of holes using interference lithography

Description: Optical interference lithography offers a robust patterning technology capable of achieving high spatial resolution over extremely large field sizes ( {approx}1 m ). Here, we compare two different approaches for fabricating arrays of holes using interferometric techniques. We show that by applying an image reversal process to standard two-beam interference lithography, arrays of high aspect ratio holes can be generated. This process scales to submicron periods and allows holes as small as 0.1 m… more
Date: May 28, 1997
Creator: Fernandez, A.; Decker, J. Y.; Herman, S. M.; Phillion, D. W.; Sweeney, D. W. & Perry, M. D.
Partner: UNT Libraries Government Documents Department
open access

Criticality parameters for tank waste evaluation

Description: Nuclear criticality parameters were developed as a basis for evaluating criticality safety for waste stored in the high-level waste tank farms on the Hanford Site in Washington State. The plutonium critical concentration and critical mass were calculated using a conservative waste model (CWM). The primary requirement of a CWM is that it have a lower neutron absorption than any actual waste. Graphs are provided of the critical mass as a function of plutonium concentration for spheres and for uni… more
Date: May 19, 1997
Creator: Rogers, C. A.
Partner: UNT Libraries Government Documents Department
open access

Investigation and deactivation of B Plant HEPA filters

Description: This paper describes the integrated approach used to manage environmental, safety, and health considerations related to the B Plant canyon exhaust air filters at the US Department of Energy (DOE) Hanford Site. The narrative illustrates the development and implementation of integrated safety management as applied to a facility and its systems undergoing deactivation. During their lifetime, the high efficiency particulate air (HEPA) filters prevented the release of significant quantities of radio… more
Date: May 12, 1997
Creator: Roege, P. E.
Partner: UNT Libraries Government Documents Department
open access

Over-the-road shock and vibration testing of the radioisotope thermoelectric generator transportation system

Description: Radioisotope Thermoelectric Generators (RTG) convert heat generated by radioactive decay into electricity through the use of thermocouples. The RTGs have a long operating life, are reasonably lightweight, and require little or no maintenance, which make them particularly attractive for use in spacecraft. However, because RTGs contain significant quantities of radioactive materials, normally plutonium-238 and its decay products, they must be transported in packages built in accordance with Title… more
Date: May 1, 1997
Creator: Becker, D. L.
Partner: UNT Libraries Government Documents Department
open access

Techniques for Identifying and Measuring High Order Modes in RF Cavities

Description: We report on a number of techniques which can be used to unravel the higher-order-mode spectrum of an RF cavity. Most of these techniques involve the application of basic symmetry principles and require for their application only that the cavity exhibit some basic symmetry, possibly broken by the presence of couplers, apertures, etc., which permits a classification of these modes in terms of some property characterized by that symmetry, e.g., multipolarity for a cavity which is basically a figu… more
Date: May 1, 1997
Creator: Goldberg, D.A. & Rimmer, R.A.
Partner: UNT Libraries Government Documents Department
open access

Signal sciences workshop proceedings

Description: This meeting is aimed primarily at signal processing and controls. The technical program for the 1997 Workshop includes a variety of efforts in the Signal Sciences with applications in the Microtechnology Area a new program at LLNL and a future area of application for both Signal/Image Sciences. Special sessions organized by various individuals in Seismic and Optical Signal Processing as well as Micro-Impulse Radar Processing highlight the program, while the speakers at the Signal Processing Ap… more
Date: May 1, 1997
Creator: Candy, J. V.
Partner: UNT Libraries Government Documents Department
open access

Picosecond-Resolution "Slice" Emittance Measurement of Electron-Bunches.

Description: The Slice Emittance diagnostic is applicable to particle bunches in a linac that are of the order of a few degrees of phase long. In this technique, the transverse phase space of a longitudinal slice about one degree long is measured. The Slice Emittance diagnostic has been demonstrated on an electron bunch produced by a laser-photocathode RF gun. We measured the transverse beam matrix of one picosecond slices out of a 10 picosecond long bunch (about 10 degrees at the RF frequency of 2856 MHz).… more
Date: May 12, 1997
Creator: Ben-Zvi, Ilan; Qiu, Joe X. & Wang, Xijie
Partner: UNT Libraries Government Documents Department
open access

Microwave Instability Thresholds.

Description: No Description Available.
Date: May 12, 1997
Creator: Zhang, S. Y.
Partner: UNT Libraries Government Documents Department
open access

On the Geometry of the Quantum Poincare Group

Description: We review the construction of the multiparametric inhomogeneousorthogonal quantum group ISO{sub q,r}(N) as a projection from SO{sub q,r}(N+2), and recall the conjugation that for N=4 leads to the quantum Poincare group. We study the properties of the universal enveloping algebra U{sub q,r}(iso(N)), and give an R-matrix formlation. A quantum Lie algebra and a bicovariant differential calculus on twisted ISO(N) are found.
Date: May 1, 1997
Creator: Aschieri, P.
Partner: UNT Libraries Government Documents Department
open access

[News Article: Experiments Give Hope For Immunity to Virus]

Description: A news article from the Washington Post discussing the difficulties of finding a vaccine to stop HIV transmission and recent tests that are leading researchers to be hopeful about a possible vaccine.
Date: May 19, 1997
Creator: Weiss, Rick
Partner: UNT Libraries Special Collections
open access

[News Article: HIV's Hidden Epitopes Now a Tempting Vaccine Target]

Description: A news article from AIDS Weekly Plus covering researchers' gathering at the ninth Annual Meeting of the National Cooperative Vaccine Development Groups for AIDS (NCVDG) to discuss a new strategy to pursue an effective vaccine for HIV.
Date: May 19, 1997
Creator: DeNoon, Daniel J.
Partner: UNT Libraries Special Collections
open access

[News Article: Baltimore Committee]

Description: A news article covering the ninth Annual Meeting of the National Cooperative Vaccine Development Groups for AIDS (NCVDG) and the contributions David Baltimore is making to AIDS research and HIV vaccine development.
Date: May 19, 1997
Creator: DeNoon, Daniel J.
Partner: UNT Libraries Special Collections
open access

[News Article: Clinton Appeals to Science for an AIDS Vaccine]

Description: A news article from the Washington Post discussing Bill Clinton's recent commencement address that he used as a platform to urge the scientific community to find a vaccine to prevent the transmission of HIV/AIDS.
Date: May 19, 1997
Creator: Harris, John F.
Partner: UNT Libraries Special Collections
open access

Change in Field Harmonics After Quench and Thermal Cycles in Superconducting Magnets

Description: A change in field harmonics after quench and thermal cycles has been observed in superconducting magnets for the Relativistic Heavy Ion Collider (RHIC). This paper presents the results of a systematic investigation of this effect in a number of RHIC dipole and quadrupole magnets. These changes in field harmonics may limit the ultimate field quality and its reproducibility in superconducting magnets. A change in pre-stress has also been observed after quench and thermal cycles. A possible link b… more
Date: May 12, 1997
Creator: Gupta, R.; Jain, A.; Muratore, J.; Wanderer, P.; Willen, E. & Wyss, C.
Partner: UNT Libraries Government Documents Department
open access

RHIC D0 Insertion Dipole Design Iterations During Production

Description: Iterations to the cross section of the Relativistic Heavy Ion Collider (RHIC) D0 Insertion Dipole magnets were made during the production. This was included as part of the production plan because no R&D or pre-production magnets were built prior to the start of production. The first magnet produced had the desired coil pre-stress and low field harmonics in the body of the magnet and is therefore being used in the RHIC Machine. On the first eight magnets, iterations were carried out to minim… more
Date: May 12, 1997
Creator: Schmalzle, J.; Anerella, M.; Ganetis, G.; Ghosh, A.; Gupta, R.; Jain, A. et al.
Partner: UNT Libraries Government Documents Department
open access

Preparation of multilayered materials in cross-section for in situ TEM tensile deformation studies

Description: The success of in-situ transmission electron microscopy experimentation is often dictated by proper specimen preparation. We report here a novel technique permitting the production of cross-sectioned tensile specimens of multilayered films for in-situ deformation studies. Of primary importance in the development of this technique is the production of an electron transparent micro-gauge section using focused ion beam technology. This microgauge section predetermines the position at which plastic… more
Date: May 13, 1997
Creator: Wall, M. A.
Partner: UNT Libraries Government Documents Department
open access

How much is energy R and D worth?

Description: The value of energy technology R and D as an insurance investment to reduce the cost of climate change stabilization, oil price shocks, urban air pollution, and energy disruptions is estimated to be $5-8 billion/year in sum total. However, the total that is justified is actually less than this sum because some R and D is applicable to more than one risk. nevertheless, the total DOE investment in energy technology R and D (about $1.3 billion/year in FY97) seems easily justified by its insurance … more
Date: May 6, 1997
Creator: Schock, R. N., LLNL
Partner: UNT Libraries Government Documents Department
open access

Wake properties of a stripline beam kicker

Description: The transport of a high current relativistic electron beam in a stripline beam kicker is strongly dependent on the wake properties of the structure. The effect of the beam-induced fields on the steering of the beam must be determined for a prescribed trajectory within the structure. A 3-D time domain electromagnetic code is used to determine the wake fields and the resultant Lorentz force on the beam both for an ultra-relativistic electron beam moving parallel to the beamline axis as well as a … more
Date: May 27, 1997
Creator: Poole, B. R., LLNL
Partner: UNT Libraries Government Documents Department
open access

Measured and theoretical characterization of the RF properties of stacked, high-gradient insulator material

Description: Recent high-voltage breakdown experiments of periodic metallic-dielectric insulating structures have suggested several interesting high-gradient applications. One such area is the employment of high-gradient insulators in high-current, electron-beam, accelerating induction modules. For this application, the understanding of the rf characteristics of the insulator plays an important role in estimating beam-cavity interactions. In this paper, we examine the rf properties of the insulator comparin… more
Date: May 9, 1997
Creator: Houck, T. L., LLNL
Partner: UNT Libraries Government Documents Department
open access

Wake properties of a stripline beam kicker

Description: The transport of a high current relativistic electron beam in a stripline beam kicker is strongly dependent on the wake properties of the structure. The effect of the beam-induced fields on the steering of the beam must be determined for a prescribed trajectory within the structure. A 3-D time domain electromagnetic code is used to determine the wake fields and the resultant Lorentz force on the beam both for an ultra-relativistic electron beam moving parallel to the beamline axis as well as a … more
Date: May 8, 1997
Creator: Poole, B. R., LLNL
Partner: UNT Libraries Government Documents Department
open access

Hard target penetrator explosive development optimization of fragment, blast and survivability properties of explosives for hard target applications

Description: Several new explosives have been developed for hard target and related applications. Materials having energy densities as high as 20 KJ/cc have been made. Mid-scale field trials have been carried out at Eglin Air Force Base. Fragmentation improvements 150% that of Tritonal have been attained.
Date: May 1, 1997
Creator: Simpson, R. L., LLNL
Partner: UNT Libraries Government Documents Department
open access

Advanced array techniques for unattended ground sensor applications

Description: Sensor arrays offer opportunities to beam form, and time-frequency analyses offer additional insights to the wavefield data. Data collected while monitoring three different sources with unattended ground sensors in a 16-element, small-aperture (approximately 5 meters) geophone array are used as examples of model-based seismic signal processing on actual geophone array data. The three sources monitored were: (Source 01). A frequency-modulated chirp of an electromechanical shaker mounted on the f… more
Date: May 6, 1997
Creator: Followill, Fred E.; Wolford, James K. & Candy, James V.
Partner: UNT Libraries Government Documents Department
open access

A Helical Magnet Design for RHIC

Description: Helical dipole magnets are required in a project for the Relativistic Heavy Ion Collider (RHIC) to control and preserve the beam polarization in order to allow the collision of polarized proton beams. Specifications are for low current superconducting magnets with a 100 mm coil aperture and a 4 Tesla field in which the field rotates 360 degrees over a distance of 2.4 meters. A magnet meeting the requirements has been developed that uses a small diameter cable wound into helical grooves machined… more
Date: May 12, 1997
Creator: Willen, E.; Gupta, R.; Jain, A.; Kelly, E.; Morgan, G.; Muratore, J. et al.
Partner: UNT Libraries Government Documents Department
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