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A comparison of the shielding performances of the AT-400A, Model FL and Model AL-R8 containers (open access)

A comparison of the shielding performances of the AT-400A, Model FL and Model AL-R8 containers

A comparison of the neutron and photon dose rates at different locations on the outside surface of the Model AL-RB, Model FL and the AT-400A containers for a given pit load has been done in order to understand the shielding characteristics of these containers. The Model AL-R8 is not certified for transport and is only used for storage of pits, while the Model FL is a certified Type B pit transportation container. The AT-400A is being developed as a type B pit storage and transportation container. The W48, W56 and B83 pits were chosen for this study because of their encompassing features with regard to other pits presently being stored. A detailed description of the geometry and materials of these containers and of the neutron and photon emission spectra from the actinide materials present in the pit have been used in the calculations of the total dose rates. The calculations have been done using the three-dimensional, neutron-photon Monte Carlo code MCNP. The results indicate the need for a containment vessel (CV), as is found in the Model FL and AT-400A containers, in order to assure compliance with 10 CFR 71 regulations. The absence of a CV in the AL-R8 container …
Date: April 28, 1995
Creator: Hansen, L. F.
System: The UNT Digital Library
Progress toward a prototype recirculating induction accelerator for heavy-ion fusion (open access)

Progress toward a prototype recirculating induction accelerator for heavy-ion fusion

The US Inertial Fusion Energy (IFE) Program is developing induction accelerator technology toward the goal of electric power production using Heavy-Ion beam-driven inertial Fusion (HIF). The recirculating induction accelerator promises driver cost reduction by repeatedly passing the beam through the same set of accelerating and focusing elements. The authors present plans for and progress, toward a small (4.5-m diameter) prototype recirculator which will accelerate K{sup +} ions through 15 laps, from 80 to 320 keV and from 2 to 8 mA. Beam confinement is effected via permanent-magnet quadrupoles; bending is via electric dipoles. Scaling laws, and extensive particle and fluid simulations of the space-charge dominated beam behavior, have been used to arrive at the design. An injector and matching section are operational. Initial experiments are investigating intense-beam transport in a linear magnetic channel; near-term plans include studies of transport around a bend. Later experiments will study, insertion/extraction and acceleration with centroid control.
Date: April 28, 1995
Creator: Friedman, A.; Barnard, J.J. & Cable, M.D.
System: The UNT Digital Library
Electron Acceleration in Relativistic Plasma Waves Generated by a Single Frequency Short-Pulse Laser (open access)

Electron Acceleration in Relativistic Plasma Waves Generated by a Single Frequency Short-Pulse Laser

Experimental evidence for the acceleration of electrons in a relativistic plasma wave generated by Raman forward scattering (SRS-F) of a single-frequency short pulse laser are presented. A 1.053 {mu}m, 600 fsec, 5 TW laser was focused into a gas jet with a peak intensity of 8{times}10{sup 17} W/cm{sup 2}. At a plasma density of 2{times}10{sup 19} cm{sup {minus}3}, 2 MeV electrons were detected and their appearance was correlated with the anti-Stokes laser sideband generated by SRS-F. The results are in good agreement with 2-D PIC simulations. The use of short pulse lasers for making ultra-high gradient accelerators is explored.
Date: April 27, 1995
Creator: Coverdale, C. A.; Darrow, C. B.; Decker, C. D.; Mori, W. B.; Tzeng, K. C.; Clayton, C. E. et al.
System: The UNT Digital Library
Emission, plasma formation, and brightness of a PZT ferroelectric cathode (open access)

Emission, plasma formation, and brightness of a PZT ferroelectric cathode

We have measured an 36-A-cm{sup {minus}2} current emission density over the surface area of an 11.4-cm{sup 2}-area Lead-Titanate- Zirconate (PZT) ferroelectric cathode with a pulsed anode-cathode (A-K) potential of 50 kV. We have also observed currents above those predicted by classical Child-Langmuir formula for a wide variety of cases. Since a plasma within the A-K gap could also lead to increase current emission we are attempting to measure the properties of the plasma near the cathode surface at emission time. In other measurements, we have observed strong gap currents in the absence of an A-K potential. Further, we continue to make brightness measurements of the emitted beam and observe spatially non-uniform emission and large shot-to-shot variation. Measurements show individual beamlets with a brightness as high 10{sup 11} Am{sup {minus}2} rad{sup {minus}2}.
Date: April 27, 1995
Creator: Sampayan, S.; Caporaso, G.; Trimble, D. & Westenskow, G.
System: The UNT Digital Library
High gradient insulator technology for the dielectric wall accelerator (open access)

High gradient insulator technology for the dielectric wall accelerator

Insulators composed of finely spaced alternating layers of dielectric and metal are thought to minimize secondary emission avalanche (SEA) growth. Most data to date was taken with small samples (order 10 cm{sup 2} area) in the absence of an ion or electron beam. The authors have begun long pulse (>1 {mu}s) high voltage testing of small hard seal samples. Further, they have performed short pulse (20 ns) high voltage testing of moderate scale bonded samples (order 100 cm{sup 2} area) in the presence of a 1 kA electron beam. Results thus far indicate a 1.0 to 4.0 increase in the breakdown electric field stress is possible with this technology.
Date: April 27, 1995
Creator: Sampayan, S.; Caporaso, G. & Carder, B.
System: The UNT Digital Library
Immobilization as a route to surplus fissile materials disposition (open access)

Immobilization as a route to surplus fissile materials disposition

In the aftermath of the Cold War, the US and Russia have agreed to large reductions in nuclear weapons. To aid in the selection of long-term management options, DOE has undertaken a multifaceted study to select options for storage and disposition of plutonium (Pu) in keeping with the national policy that Pu must be subjected to the highest standards of safety, security, and accountability. One alternative being considered is immobilization. To arrive at a suitable immobilization form, the authors first reviewed published information on high-level waste (HLW) immobilization technologies in order to identify 72 possible Pu immobilization forms to be prescreened. Surviving forms were screened using multiattribute analysis to determine the most promising technologies. Promising immobilization families were further evaluated to identify chemical, engineering, environmental, safety, and health problems that remain to be solved prior to making technical decisions as to the viability of using the form for long-term disposition of plutonium. All data, analyses, and reports are being provided to the DOE Fissile Materials Disposition Project Office to support the Record of Decision that is anticipated in the fourth quarter of FY96.
Date: April 27, 1995
Creator: Gray, L.W. & Kan, T.
System: The UNT Digital Library
Optically induced surface flashover switching for the dielectric wall accelerator (open access)

Optically induced surface flashover switching for the dielectric wall accelerator

Fast, low jitter command triggered switching is key to the successful implementation of the dielectric wall accelerator (DWA). We are studying a UV induced vacuum surface flashover switch for this purpose. We present our initial data using a Nd:YAG laser incident onto a high gradient insulator surface at 1{omega}, 2{omega}, and 4{omega}. Best 1{sigma} jitter was <1 ns with no degradation of the switch after 500 shots.
Date: April 27, 1995
Creator: Sampayan, S.; Caporaso, G.; Carder, B.; Norton, M.; Trimble, D. & Elizondo, J.
System: The UNT Digital Library
Panama Canal capacity analysis (open access)

Panama Canal capacity analysis

Predicting the transit capacities of the various Panama Canal alternatives required analyzing data on present Canal operations, adapting and extending an existing computer simulation model, performing simulation runs for each of the alternatives, and using the simulation model outputs to develop capacity estimates. These activities are summarized in this paper. A more complete account may be found in the project final report (TAMS 1993). Some of the material in this paper also appeared in a previously published paper (Rosselli, Bronzini, and Weekly 1994).
Date: April 27, 1995
Creator: Bronzini, M.S.
System: The UNT Digital Library
Hybrid vehicle system studies and optimized hydrogen engine design (open access)

Hybrid vehicle system studies and optimized hydrogen engine design

We have done system studies of series hydrogen hybrid automobiles that approach the PNGV design goal of 34 km/liter (80 mpg), for 384 km (240 mi) and 608 km (380 mi) ranges. Our results indicate that such a vehicle appears feasible using an optimized hydrogen engine. We have evaluated the impact of various on-board storage options on fuel economy. Experiments in an available engine at the Sandia CRF demonstrated NO{sub x} emissions of 10 to 20 ppM at an equivalence ratio of 0.4, rising to about 500 ppm at 0.5 equivalence ratio using neat hydrogen. Hybrid simulation studies indicate that exhaust NO{sub x} concentrations must be less than 180 ppM to meet the 0.2 g/mile ULEV or Federal Tier II emissions regulations. LLNL has designed and fabricated a first generation optimized hydrogen engine head for use on an existing Onan engine. This head features 15:1 compression ratio, dual ignition, water cooling, two valves and open quiescent combustion chamber to minimize heat transfer losses. Initial testing shows promise of achieving an indicated efficiency of nearly 50% and emissions of less than 100 ppM NO{sub x}. Hydrocarbons and CO are to be measured, but are expected to be very low since their …
Date: April 26, 1995
Creator: Smith, J. R. & Aceves, S.
System: The UNT Digital Library
Choppertron II (open access)

Choppertron II

We present experimental results of a version of the Choppertron microwave generator designed to work with the high emittance beam of the Advanced Test Accelerator (ATA). Simulations showed that a 800-A, 120 {pi} cm-mrad beam (typical of ATA), could produce 800 MW of rf (11.4 GHz) power using two 12-cell, traveling-wave output structures. Funding contraints prevented final tuning of the modulator system and limited the experiment to 530 MW in narrow pulses. Over 400 MW were extracted from a single output structure through fundamental waveguide. Beam breakup was successfully suppressed with >800 amperes transported through the extraction section.
Date: April 25, 1995
Creator: Houck, T.L.; Westenskow, G.A.; Haimson, J. & Mecklenburg, B.
System: The UNT Digital Library
Development of beam position monitors for heavy ion recirculators (open access)

Development of beam position monitors for heavy ion recirculators

Work is underway at the Lawrence Livermore National Laboratory to design and build a small-scale, heavy ion recirculating induction accelerator. An essential part of this design work is the development of small nonintercepting diagnostics to measure beam current and position. This paper describes some of this work, with particular emphasis on the development of a small capacitive probe beam position monitor to resolve beam position to the 100 {mu}m level in a 6 cm diameter beam pipe. Initial measured results with an 80 keV potassium ion beam are presented.
Date: April 25, 1995
Creator: Deadrick, F. J.; Barnard, J. J.; Fessenden, T. J.; Meridith, J. W. & Rintamaki, J.
System: The UNT Digital Library
A MEMS-based miniature DNA analysis system (open access)

A MEMS-based miniature DNA analysis system

We detail the design and development of a miniature thermal cycling instrument for performing the polymerase chain reaction (PCR) that uses microfabricated, silicon-based reaction chambers. The MEMS-based, battery-operated instrument shows significant improvements over commercial thermal cycling instrumentation. Several different biological systems have been amplified and verified with the miniature PCR instrument including the Human Immunodeficiency Virus; both cloned and genomic DNA templates of {beta} globin; and the genetic disease, Cystic Fibrosis from human DNA. The miniaturization of a PCR thermal cycler is the initial module of a fully-integrated portable, low-power, rapid, and highly efficient bioanalytical instrument.
Date: April 25, 1995
Creator: Northrup, M.A.; Gonzalez, C. & Hadley, D.
System: The UNT Digital Library
Transport of a Partially-Neutralized Ion Beam in a Heavy-Ion Fusion Reactor Chamber (open access)

Transport of a Partially-Neutralized Ion Beam in a Heavy-Ion Fusion Reactor Chamber

In a heavy-ion driven, inertial confinement fusion power plant, a space-charge dominated beam of heavy ions must be transported through a reactor chamber and focused on a 2-3 mm spot at the target. The spot size at the target is determined by the beam emittance and space charge, plus chromatic aberrations in the focusing lens system and errors in aiming the beam. The gain of the ICF capsule depends on the focal spot size. We are investigating low density, nearly-ballistic transport using an electromagnetic, r-z particle-in-cell code. Even at low density (n {approx} 5 {times} 10{sup 13} cm{sup {minus}3}), beam stripping may be important. To offset the effects of stripping and reduce the space charge, the beam is partially charge neutralized via a pre-formed plasma near the chamber entrance. Additional electrons for charge neutralization come from ionization of the background gas by the beam. Simulations have shown that stripping can greatly increase the spot size; however, partial neutralization can offset most of this increase.
Date: April 25, 1995
Creator: Callahan, D. A. & Langdon, A. B.
System: The UNT Digital Library
Dynamics of gas-filled hohlraums (open access)

Dynamics of gas-filled hohlraums

In order to prevent high-Z plasma from filling in the hohlraum in indirect drive experiments, a low-Z material, or tamper is introduced into the hohlraum. This material, when fully ionized is typically less than one-tenth of the critical density for the laser light used to illuminate the hohlraum. This tamper absorbs little of the laser light, thus allowing most of the laser energy to be absorbed in the high-Z material. However, the pressure associated with this tamper is sufficient to keep the hohlraum wall material from moving a significant distance into the interior of the hohlraum. In this paper the authors discuss measurements of the motion of the interface between the tamper and the high-Z hohlraum material. They also present measurements of the effect the tamper has on the hohlraum temperature.
Date: April 24, 1995
Creator: Orzechowski, T.J.; Kauffman, R.L. & Kirkwood, R.K.
System: The UNT Digital Library
Test results of a combined distributed ion pump/non-evaporable getter pump design developed as a proposed alternative pumping system for the PEP-II asymmetric B-Factory collider (open access)

Test results of a combined distributed ion pump/non-evaporable getter pump design developed as a proposed alternative pumping system for the PEP-II asymmetric B-Factory collider

The authors have built and tested an all-in-one combination plate-type distributed ion pump/non-evaporable getter pump design (DIP/NEG) considered as a proposed alternative pumping system for the PEP-II B-Factory High Energy Ring (HER). The DIP portion of the design used a Penning cell hole size of 12 mm in a mostly uniform magnetic field of 0.18 T. The NEG portion of the design used commercially available non-evaporable getter material type St-707{trademark}. A detailed description of the design is presented along with results of pumping speed measurements.
Date: April 24, 1995
Creator: Holdener, F.; Behne, D. & Hathaway, D.
System: The UNT Digital Library
Test results of pre-production prototype distributed ion pump design for the PEP-II Asymmetric B-Factory collider (open access)

Test results of pre-production prototype distributed ion pump design for the PEP-II Asymmetric B-Factory collider

We have built and tested a plate-type pre-production distributed Ion Pump (DIP) for the PEP-II B-Factory High Energy Ring (HER). The design has been an earlier design to use less materials and to costs. Penning cell hole sizes of 15, 18, and 21 mm have been tested in a uniform magnetic field of 0.18 T to optimize pumping speed. The resulting final DIP design consisting of a 7-plate, 15 mm basic cell size anode was magnetic field of the HER dipole. A description of the final optimized DIP design will be presented along with the test results of the pumping speed measurements.
Date: April 24, 1995
Creator: Holdener, F. R.; Behne, D. & Hathaway, D.
System: The UNT Digital Library
Three dimensional simulations of a small induction recirculator accelerator (open access)

Three dimensional simulations of a small induction recirculator accelerator

A recirculating induction accelerator has potential cost advantages for a heavy-ion fusion driver. In order to explore the physics and technological issues, a small prototype recirculator is being built. The three dimensional particle-in-cell code, WARP3d, is being used in the design and analysis of the experiments. WARP3d is used to examine the behavior of the beam in the electric dipoles and in the non-linear fields associated with the accelerator lattice elements. The dipoles have focusing and fringe fields which can adversely affect the beam quality. Both single particle and full beam dynamics are examined in the dipoles using realistic geometries. Dipole plate designs which minimize the adverse effects are described. The non-linear fields associated with the permanent magnetic quadrupoles have been included in the simulations. They were found to have little effect on the quality of the beam.
Date: April 24, 1995
Creator: Grote, D. P.; Friedman, A. & Haber, I.
System: The UNT Digital Library
A practical microgripper by fine alignment, eutectic bonding and SMA actuation (open access)

A practical microgripper by fine alignment, eutectic bonding and SMA actuation

A silicon microgripper with a large gripping force, a relatively rigid structural body, and flexibility in functional design is presented. The actuation is generated by Ni-Ti-Cu shape memory alloy (SMA) films and the stress induced can deflect each side of the microgripper up to 55 {mu}m for a total gripping motion of 110 {mu}m. When fully open, the force exerted by the film corresponds to a 40 mN gripping force on the tip of the gripper.
Date: April 21, 1995
Creator: Lee, A. P.; Ciarlo, D. R. & Krulevitch, P. A.
System: The UNT Digital Library
A refuelable zinc/air battery for fleet electric vehicle propulsion (open access)

A refuelable zinc/air battery for fleet electric vehicle propulsion

We report the development and on-vehicle testing of an engineering prototype zinc/air battery. The battery is refueled by periodic exchange of spent electrolyte for zinc particles entrained in fresh electrolyte. The technology is intended to provide a capability for nearly continuous vehicle operation, using the fleet s home base for 10 minute refuelings and zinc recycling instead of commercial infrastructure. In the battery, the zinc fuel particles are stored in hoppers, from which they are gravity fed into individual cells and completely consumed during discharge. A six-celled (7V) engineering prototype battery was combined with a 6 V lead/acid battery to form a parallel hybrid unit, which was tested in series with the 216 V battery of an electric shuttle bus over a 75 mile circuit. The battery has an energy density of 140 Wh/kg and a mass density of 1.5 kg/L. Cost, energy efficiency, and alternative hybrid configurations are discussed.
Date: April 20, 1995
Creator: Cooper, J.F.; Fleming, D.; Hargrove, D.; Koopman, R. & Peterman, K.
System: The UNT Digital Library
Photographic as-builts for Argonne National Laboratory-West (open access)

Photographic as-builts for Argonne National Laboratory-West

Located 35 miles West of Idaho Falls, Idaho, Argonne National Laboratory-West operates a number of nuclear facilities for the Department of Energy (DOE) through the University of Chicago. Part of the present mission of Argonne National Laboratory-West includes shutdown of the EBR-II Reactor. In order to accomplish this task the Engineering-Drafting Department is exploring cost effective methods of providing as-building services. A new technology of integrating photographic images and AUTOCAD drawing files is considered one of those methods that shows promise.
Date: April 19, 1995
Creator: Sherman, E. K. & Wiegand, C. V.
System: The UNT Digital Library
Hydrogen transport and storage in engineered glass microspheres (open access)

Hydrogen transport and storage in engineered glass microspheres

New, high strength glass microspheres filled with pressurized hydrogen exhibit densities which make them attractive for bulk hydrogen storage and transport. The membrane tensile stress at failure for our engineered glass microspheres is about 150,000 psi, permitting a threefold increase in pressure limit and storage capacity above commercial microspheres, which have been studied a decade ago and have been shown to fail at membrane stresses of 50,000 psi. Our analysis relating glass microspheres for hydrogen transport with infrastructure and economics, indicate that pressurized microspheres can be economically competitive with other forms of bulk rail and truck transport such as pressurized tube transports and liquid hydrogen trailers.
Date: April 18, 1995
Creator: Rambach, G.D.
System: The UNT Digital Library
Infrared hyperspectral imaging results from vapor plume experiments (open access)

Infrared hyperspectral imaging results from vapor plume experiments

In this article, recent measurements made with LIFTIRS, the Livermore Imaging Fourier Transform InfraRed Spectrometer, are presented. The experience gained with this instrument has produced a variety of insights into the tradeoffs between signal to noise ratio (SNR), spectral resolution and temporal resolution for time multiplexed Fourier transform imaging spectrometers. This experience has also clarified the practical advantages and disadvantages of Fourier transform hyperspectral imaging spectrometers regarding adaptation to varying measurement requirements on SNR vs. spectral resolution, spatial resolution and temporal resolution.
Date: April 17, 1995
Creator: Bennett, C. L.; Carter, M. R. & Fields, D. J.
System: The UNT Digital Library
The positions of λₘₐₓ for some trimethylsilyl-substituted silylenes (open access)

The positions of λₘₐₓ for some trimethylsilyl-substituted silylenes

This article describes how low-temperature photolysis of tris(trimethylsilyl)silane derivatives in a 3-methylpentane glass at 77 K yields hexamethyldisilane and trimethylsilyl-substituted silylenes.
Date: April 17, 1995
Creator: Bott, S. G.; Marshall, Paul; Wagenseller, P. E.; Wang, Y. & Conlin, R. T.
System: The UNT Digital Library
Measuring Enthalpies of Formation Using Thick Multilayer Foils and Differential Scanning Calorimetry (open access)

Measuring Enthalpies of Formation Using Thick Multilayer Foils and Differential Scanning Calorimetry

The ability to measure formation enthalpies of compounds at relatively low temperatures using thick multilayer foils and differential scanning calorimetry is demonstrated. Cu/Zr and Al/Zr multilayers were deposited onto Si and glass substrates using a planetary, magnetron source sputtering system. The as-deposited foils were removed from their substrates and heated from 50 to 725C in a differential scanning calorimeter (DSC). The Cu/Zr samples, which are all Cu-rich, showed three distinct, reproducible, and exothermic solid state reactions. The heats from the first two reactions were summed and analyzed to measure 14.3{plus_minus}0.3 kJ/mol for Cu{sub 51}Zr{sub 14}`s enthalpy of formation. This quantity agrees with the single value of {Delta}H{sub f} = 14.07{plus_minus}1.07kJ/mol reported for this compound. The composition of the Al/Zr multilayers ranged from 8 at% Zr to 64 at% Zr. These samples showed a variety of distinct, reproducible, and exothermic solid state reactions. The total heats from these reactions were summed and analyzed to measure enthalpies of formation for five different Al-Zr alloys. The results compare favorably with literature values of {Delta}H{sub f}. Advantages of measuring enthalpies of formation using thick multilayer foil samples and low temperature DSC calorimetry are discussed.
Date: April 14, 1995
Creator: Weihs, T. P.; Barbee, T. W., Jr. & Wall, M. A.
System: The UNT Digital Library