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in subjects: "426000 -- Engineering-- Components, Electron Devices & Circuits-- 1990-"

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Computation of the current density in nonlinear materials subjected to large current pulses

The finite element method and the finite difference method are used to calculate the current distribution in two nonlinear conductors. The first conductor is a small ferromagnetic wire subjected to a current pulse that rises to 10,000 Amperes in 10 microseconds. Results from the transient thermal and transient magnetic solvers of the finite element code FLUX2D are used to compute the current density in the wire. The second conductor is a metal oxide varistor. Maxwell's equations, Ohm's law and … more

Date: January 1, 1990

Creator: Hodgdon, M. L.; Hixson, R. S. & Parsons, W. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Mathematical modelling of part voltage and weld current in resistance welders

A mathematical model is presented to describe the part voltage and weld current that occur in a single-phase resistance welder. Developing an accurate model of part voltage and current is the first step toward understanding instrumentation, testing, calibration, and measurement requirements. Measurement requirements for dynamic part resistance, calculated from these basic process variables, can ultimately be determined using this analysis. This model utilizes electrical characteristics of the w… more

Date: September 11, 1990

Creator: Destefan, D.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Traveling-wave-tube simulation: The IBC (Interactive Beam-Circuit) code

Interactive Beam-Circuit (IBC) is a one-dimensional many particle simulation code which has been developed to run interactively on a PC or Workstation, and displaying most of the important physics of a traveling-wave-tube. The code is a substantial departure from previous efforts, since it follows all of the particles in the tube, rather than just those in one wavelength, as commonly done. This step allows for nonperiodic inputs in time, a nonuniform line and a large set of spatial diagnostics.… more

Date: September 26, 1989

Creator: Morey, I. J. & Birdsall, C. K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

System response to relay chatter

An important aspect of the qualification of safety related systems, is the assessment of the possibility and consequences of seismic or vibration induced relay chatter. The current rules, contained in ANSI/IEEE C37.98 and the SQUG GIP, consider as seismic induced failure'' of a relay, a chatter contact in excess of 2 milliseconds. While this rule is clear in defining failure'' of single relay, the definition of failure'' becomes more problematic when we consider the alignment of an assembly of … more

Date: January 1, 1992

Creator: Antaki, G. A. & Radder, J. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Procyon experiments utilizing explosively-formed fuse opening switches

In this paper we describe results from tests of an explosive pulsed power system designed to deliver 15--16 MA to a plasma flow switch (PFS). The PFS, in turn, has the goal of switching current to a z- pinch load to produce a 1-MJ implosion for x-ray generation experiments. The system consists of a MK-IX magnetic flux-compression generator, a coaxial inductive store, an explosively formed fuse (EFF) opening switch, and a vacuum power flow/PFS assembly. Figure 1 shows a completed assembly ready … more

Date: January 1, 1991

Creator: Goforth, J. H.; Oona, H.; Brownell, J. H.; Greene, A. E.; Kruse, H. W.; Lindemuth, I. R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A switched capacitor array based system for high-speed calorimetry

A sixteen channel analog transient recorder with 256 cells per channel has been fabricated as an integrated circuit. The circuit uses switched capacitor array technology to achieve simultaneous read/write capability and twelve bit dynamic range. Combined with highly parallel analog-to-digital converter and readout control circuitry being developed this system should satisfy the demanding electronics requirements for calorimeter detectors at the SSC. The system design and test results are presen… more

Date: December 1, 1991

Creator: Levi, M.; Bebek, C.; Ely, R.; Jared, R.; Kipnis, I.; Kirsten, F. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Monolithic JFET preamplifier for ionization chamber calorimeter

A monolithic charge sensitive preamplifier using exclusively n-channel diffused JFETs has been designed and is now being fabricated by INTERFET Corp. by means of a dielectrically isolated process which allows preserving as much as possible the technology upon which discrete JFETs are based. A first prototype built by means of junction isolated process has been delivered. The characteristics of monolithically integrated JFETs compare favorably with discrete devices. First results of tests of a p… more

Date: October 1, 1990

Creator: Radeka, V.; Rescia, S. (Brookhaven National Lab., Upton, NY (United States)); Manfredi, P.F. & Speziali, V. (Pavia Univ. (Italy). Dipt. di Elettronica)

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Evaluation of FOXFET biased ac-coupled silicon strip detector prototypes for CDF SVX upgrade

Silicon microstrip detectors for high-precision charged particle position measurements have been used in nuclear and particle physics for years. The detectors have evolved from simple surface barrier strip detectors with metal strips to highly complicated double-sided AC-coupled junction detectors. The feature of AC-coupling the readout electrodes from the diode strips necessitates the manufacture of a separate biasing structure for the strips, which comprises a common bias line together with a… more

Date: March 1, 1992

Creator: Laakso, M. (Fermi National Accelerator Lab., Batavia, IL (United States) Research Inst. for High Energy Physics (SEFT), Helsinki (Finland))

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Power supply regulation systems installed in the Fermilab accelerators

A variety of current and voltage regulation systems have been installed in the Fermilab large magnet system. The four major systems employ different methods to achieve the desired degree of regulation. The methods include computer control and feedback, adaptive learning, precision (10ppm) current monitoring, and the use of feed-forward signals. This paper will explain each method used and present the measured regulation of the above systems. Also an overview of planned upgrades and improvements… more

Date: November 1, 1991

Creator: Hays, S.; Wolff, D. & Pfeffer, H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A high resolution 14-bit ADC for Gammasphere Project

A system of 110 high performance A/D converters, required for the Gammasphere Project at the Lawrence Berkeley Laboratory, is described. The ADCs are compact, linear ([plus minus])0.006% integral, [plus minus]0.5% differential, with a conversion deadtime of 5.3 [mu]s and channel profile flatness of 50% over a 13-bit range. The converter is based on a new low power (0.25 W), low cost, monolithic high speed sampling ADC, exibiting a very high stability and no missing codes over the entire 16-bit … more

Date: October 1, 1992

Creator: Turko, B. T.; Arthur, A. A.; Galvin, J. E.; Maier, M. R. & Zizka, G. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The pad readout electronics of the SLD Warm Iron Calorimeter

The design of the pad readout electronics of the Warm Iron Calorimeter for the SLD detector at SLAC, consisting of about 9000 analog channels, is described. Results of various tests performed during the construction, installation and commissioning of the electronics mounted on the detector are presented. 10 refs., 12 figs.

Date: August 1, 1990

Creator: Burrows, P. N.; Busza, W.; Cartwright, S. L.; Friedman, J. I.; Fuess, S.; Gonzalez, S. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Harmonics suppression of vacuum chamber eddy current induced fields with application to the Superconducting Super Collider (SSC) Low Energy Booster (LEB) Magnets

This memo presents the formulation of an expression for eddy currents induced in a thin-walled conductor due to a time-dependent electromagnet field excitation. Then follows an analytical development for prediction of vacuum chamber eddy current induced field harmonics in iron-core electromagnets. A passive technique for harmonics suppression is presented with specific application to the design of the Superconducting Super Collider (SSC) Low Energy B (LEB) Magnets.

Date: December 4, 1991

Creator: Schlueter, R. D. & Halbach, K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Strained quantum well InGaSb/AlGaSb heterostructures grown by molecular beam epitaxy

Strained, modulation-doped InGaSb/AlGaSb quantum wells were grown on InP substrates by molecular beam epitaxy and characterized by magneto-transport measurements. Hole transport properties were strongly correlated with growth conditions. Shubnikov-de Haas measurements yielded a hole mass of (0.15{plus minus}0.02) m{sub o}, and hole mobilities as high as 3300 cm{sub 2}/Vs were obtained at 77K, with a density of 1.6{times}10{sub 12} cm{sup {minus}2}, thus showing promise for p-type field-effect t… more

Date: January 1, 1991

Creator: Klem, J. F.; Lott, J. A.; Schirber, J. E. & Kurtz, S. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Development of a numerical computer code and circuit element models for simulation of firing systems

Numerical simulation of firing systems requires both the appropriate circuit analysis framework and the special element models required by the application. We have modified the SPICE circuit analysis code (version 2G.6), developed originally at the Electronic Research Laboratory of the University of California, Berkeley, to allow it to be used on MSDOS-based, personal computers and to give it two additional circuit elements needed by firing systems--fuses and saturating inductances. An interact… more

Date: July 2, 1990

Creator: Carpenter, K.H. (Kansas State Univ., Manhattan, KS (USA). Dept. of Electrical and Computer Engineering)

Item Type: Report

Partner: UNT Libraries Government Documents Department

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PSR switchyard kicker system improvements

A switchyard kicker system which allows time sharing of beam between the Los Alamos WNR/LANSCE complex and other LAMPF users was redesigned as part of the Proton Storage Ring addition. The system consists of two pulsers providing 1750-ampere, 1-msec pulses to a pair of 1 meter long ferrite magnets. The system was designed to operate at 24-Hz maximum repetition rate. In 1986 a modification was made to the equipment to allow operation at 40 Hz. While the system operated reliably this way some dif… more

Date: January 1, 1991

Creator: Hardek, T.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A New VME Based High Voltage Power Supply for Large Experiments

A new VME based high voltage power supply has been developed for the D{O} experiment at Fermilab. There are three types of supplies delivering up to {plus minus}5.6 kV at 1.0 mA or +2.0 kV at 3.0 mA with a set accuracy of 1.5 V and extremely low voltage ripples. Complete computer control has allowed many special features to be developed for the supply, including user-defined control land monitor groups, variable ramp rates, and advanced histogram and graphic functions. 3 refs.

Date: November 1, 1991

Creator: Ahn, S. C.; Angstadt, R. D.; Droege, T. F.; Johnson, M. E.; MacKinnon, B. A.; McNulty, S. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

High bandwidth beam current monitor

A stripline directional coupler beam current monitor capable of measuring the time structure of a 30-ps electron beam bunch has been developed. The time response performance of the monitor compares very well with Cherenkov light produced in quartz by the electron beam. The four-pickup monitor is now used on a routine basis for measuring the beam duration, tuning for optimized beam bunching, and centering the bunch in the beam pipe.

Date: January 1, 1993

Creator: Baltrusaitis, R.M.; Ekdahl, C.A. (Los Alamos National Lab., NM (United States)); Cooper, R.G. (EG and G Energy Measurements, Inc., Goleta, CA (United States). Santa Barbara Operations); Peterson, E. & Warn, C.E. (EG and G Energy Measurements, Inc., Las Vegas, NV (United States). Las Vegas Operations)

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Optically-triggered hardened thyristors for firing set circuits

Silicon thyristors, directly triggered by light, are used to switch pulsed currents in firing set circuits. They are hardened to transient ionizing radiation by the addition of a reverse-biased compensating photodiode connected to the gate of the thyristor. Tests of these compensated devices show radiation-induced switching is completely inhibited in excess of 1.4 {times} 10{sup 9} rad (Si)/sec. 2 refs., 5 figs.

Date: January 1, 1990

Creator: Carson, R.F. & Knauss, G.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Engineering, maintenance, and new initiatives to improve LAMPF beam availability and system reliability

Two different requirements are driving engineering studies and hardware development to improve LAMPF. The first is concerned with component and system improvements to increase beam availability during the LAMPF production cycle. Hardware changes in RF, power supplies, and magnets are being implemented to increase mean time between failure and reduce time to replace or repair failed units. A joint LAMPF-Industry project is on-going to improve reliability of RF components. A component test stand … more

Date: January 1, 1992

Creator: Harris, H. W.; DeHaven, R. A.; Hart, V. E.; Parsons, W. M. & Sturrock, J. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Single event upset hardening techniques

Integrated circuit logic states are maintained by virtue of specific transistor combinations being either on'' (conducting) or off'' (nonconducting). High energy ion strikes on the microcircuit generate photocurrents whose primary detrimental effect is to make off'' transistors appear on,'' confusing the logic state and leading to single event upset (SEU). Protection against these soft errors is accomplished using either technology or circuit techniques, actions that generally impact yield and … more

Date: January 1, 1990

Creator: Weaver, H. T. & Corbett, W. T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Lightning threat warning system at the Tonopah Test Range

This report documents the lightning threat warning system at the Tonopah Test Range and the technology it uses. The report outlines each of the system's individual components and the information each contributes.

Date: July 1, 1992

Creator: Smith, R

Item Type: Report

Partner: UNT Libraries Government Documents Department

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The preparation of InAsSb/InSb SLS (strained-layer superlattice) and InSb photodiodes by MOCVD

Infrared absorption and photoluminescence have been demonstrated for InAs{sub 1-x}Sb{sub x}/InSb strained-layer superlattices (SLS's) in the 8--15 {eta}m region for As content less than 20%. This extended infrared activity is due to the type II heterojunction band offset in these SLS's. The preparation of the first MOCVD grown p-n junction diode was achieved by using dimethyltellurium as an in-type dopant. Several factors, such as background doping and dopant profiles affect the performance of … more

Date: January 1, 1990

Creator: Biefeld, R. M.; Cunningham, B. T.; Kurtz, S. R. & Wendt, J. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Inert Electrodes Program fiscal year 1988 annual report

The Inert Electrodes Program, being conducted by Pacific Northwest Laboratory (PNL), involves improving the Hall-Heroult cells used by the Aluminum Industry for the electrochemical production of aluminum. The PNL research centers on developing more energy efficient, longer-lasting anodes and cathodes and ancillary equipment. Major accomplishments for Fiscal Year 1988 are summarized below. 14 refs., 56 figs., 9 tabs.

Date: October 1, 1989

Creator: Strachan, D.M.; Marschman, S.C.; Davis, N.C.; Friley, J.R. & Schilling, C.H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Understanding and managing the effects of battery charger and inverter aging

An aging assessment of battery chargers and inverters was conducted under the auspices of the NRC's Nuclear Plant Aging Research (NPAR) Program. The intentions of this program are to resolve issues related to the aging and service wear of equipment and systems at operating reactor facilities and to assess their impact on safety. Inverters and battery chargers are used in nuclear power plants to perform significant functions related to plant safety and availability. The specific impact of a batt… more

Date: January 1, 1992

Creator: Gunther, W. (Brookhaven National Lab., Upton, NY (United States)) & Aggarwal, S. (Nuclear Regulatory Commission, Washington, DC (United States))

Item Type: Article

Partner: UNT Libraries Government Documents Department