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Improving Switching Performance of Power MOSFETs Used in High Rep-Rate, Short Pulse, High-Power Pulsers

Description: As their switching and power handling characteristics improve, solid-state devices are finding new applications in pulsed power. This is particularly true of applications that require fast trains of short duration pulses. High voltage (600-1200V) MOSFETs are especially well suited for use in these systems, as they can switch at significant peak power levels and are easily gated on and off very quickly. MOSFET operation at the shortest pulse durations is not constrained by the intrinsic capabilities of the MOSFET, but rather by the capabilities of the gate drive circuit and the system physical layout. This project sought to improve MOSFET operation in a pulsed power context by addressing these issues. The primary goal of this project is to improve the switching performance of power MOSFETs for use in high rep-rate, short pulse, high-power applications by improving the design of the gate drive circuits and the circuit layouts used in these systems. This requires evaluation of new commercial gate drive circuits and upgrading the designs of LLNL-developed circuits. In addition, these circuits must be tested with the fastest available high-voltage power MOSFETs.
Date: September 19, 2006
Creator: Cook, E G
Partner: UNT Libraries Government Documents Department

Inertial Fusion Energy's Role in Developing the Market for High Power Laser Diodes

Description: Production-cost models for high-power laser-diodes indicate systems of 10GW peak power coupled with facilitization of semi-conductor manufacturing capacity could yield costs below $0.02/Watt. This is sufficient to make IFE competitive with other nuclear power technologies.
Date: November 29, 2007
Creator: Ladran, A L; Ault, E R; Beach, R J; Campbell, J H; Erlandson, A C; Felker, A J et al.
Partner: UNT Libraries Government Documents Department

The Mercury Laser System: An Average power, gas-cooled, Yb:S-FAP based system with frequency conversion and wavefront correction

Description: We report on the operation of the Mercury laser with fourteen 4 x 6 cm{sup 2} Yb:S-FAP amplifier slabs pumped by eight 100 kW peak power diode arrays. The system was continuously run at 55 J and 10 Hz for several hours, (2 x 10{sup 5} cumulative shots) with over 80% of the energy in a 6 times diffraction limited spot at 1.047 um. Improved optical quality was achieved in Yb:S-FAP amplifiers with magneto-rheological finishing, a deterministic polishing method. In addition, average power frequency conversion employing YCOB was demonstrated at 50% conversion efficiency or 22.6 J at 10 Hz.
Date: August 31, 2005
Creator: Bibeau, C; Bayramian, A; Armstrong, P; Ault, E; Beach, R; Benapfl, M et al.
Partner: UNT Libraries Government Documents Department


Description: We discuss criteria for designing an optimal ''green field'' proton driver for a neutrino factory. The driver parameters are determined by considerations of space charge, power capabilities of the target, beam loading and available RF peak power.
Date: June 23, 2006
Partner: UNT Libraries Government Documents Department

USABC electric vehicle Battery Test Procedures Manual. Revision 2

Description: This manual summarizes the procedural information needed to perform the battery testing being sponsored by the United States Advanced Battery Consortium (USABC). This information provides the structure and standards to be used by all testing organizations, including the USABC developers, national laboratories, or other relevant test facilities.
Date: January 1, 1996
Partner: UNT Libraries Government Documents Department

High Peak Power Gain Switched Flared Waveguide Lasers

Description: We gain-switch flared waveguide lasers to obtain 14.5 W peak powers and 0.5 nJ pulse energies with laser structures compatible with the generation of diffraction-limited beams. The results are in excellent agreement with a microscopic laser model.
Date: August 5, 1999
Creator: Chow, W.W.; Indik, R.; Koch, S.W.; Mar, Alan, Vawter, G. Allen & Moloney, J.
Partner: UNT Libraries Government Documents Department

Estimating Demand Response Load Impacts: Evaluation of BaselineLoad Models for Non-Residential Buildings in California

Description: Both Federal and California state policymakers areincreasingly interested in developing more standardized and consistentapproaches to estimate and verify the load impacts of demand responseprograms and dynamic pricing tariffs. This study describes a statisticalanalysis of the performance of different models used to calculate thebaseline electric load for commercial buildings participating in ademand-response (DR) program, with emphasis onthe importance of weathereffects. During a DR event, a variety of adjustments may be made tobuilding operation, with the goal of reducing the building peak electricload. In order to determine the actual peak load reduction, an estimateof what the load would have been on the day of the event without any DRactions is needed. This baseline load profile (BLP) is key to accuratelyassessing the load impacts from event-based DR programs and may alsoimpact payment settlements for certain types of DR programs. We testedseven baseline models on a sample of 33 buildings located in California.These models can be loosely categorized into two groups: (1) averagingmethods, which use some linear combination of hourly load values fromprevious days to predict the load on the event, and (2) explicit weathermodels, which use a formula based on local hourly temperature to predictthe load. The models were tested both with and without morningadjustments, which use data from the day of the event to adjust theestimated BLP up or down.Key findings from this study are: - The accuracyof the BLP model currently used by California utilities to estimate loadreductions in several DR programs (i.e., hourly usage in highest 3 out of10 previous days) could be improved substantially if a morning adjustmentfactor were applied for weather-sensitive commercial and institutionalbuildings. - Applying a morning adjustment factor significantly reducesthe bias and improves the accuracy of all BLP models examined in oursample of buildings. - For buildings with low load variability, all BLPmodels perform reasonably well ...
Date: January 1, 2008
Creator: Coughlin, Katie; Piette, Mary Ann; Goldman, Charles & Kiliccote,Sila
Partner: UNT Libraries Government Documents Department

GeV electron beams from a laser-plasma accelerator

Description: High-quality electron beams with up to 1 GeV energy havebeen generated by a laser-driven plasma-based accelerator by guiding a 40TW peak power laser pulse in a 3.3 cm long gas-filled capillary dischargewaveguide.
Date: October 1, 2006
Creator: Schroeder, C. B.; Tóth, Cs.; Nagler, B.; Gonsalves, A. J.; Nakamura, K.; Geddes, C. G. R. et al.
Partner: UNT Libraries Government Documents Department

High-Power Laser Pulse Recirculation for Inverse Compton Scattering-Produced Gamma-Rays

Description: Inverse Compton scattering of high-power laser pulses on relativistic electron bunches represents an attractive method for high-brightness, quasi-monoenergetic {gamma}-ray production. The efficiency of {gamma}-ray generation via inverse Compton scattering is severely constrained by the small Thomson scattering cross section. Furthermore, repetition rates of high-energy short-pulse lasers are poorly matched with those available from electron accelerators, resulting in low repetition rates for generated {gamma}-rays. Laser recirculation has been proposed as a method to address those limitations, but has been limited to only small pulse energies and peak powers. Here we propose and experimentally demonstrate an alternative method for laser pulse recirculation that is uniquely capable of recirculating short pulses with energies exceeding 1 J. Inverse Compton scattering of recirculated Joule-level laser pulses has a potential to produce unprecedented peak and average {gamma}-ray brightness in the next generation of sources.
Date: April 17, 2007
Creator: Jovanovic, I; Shverdin, M; Gibson, D & Brown, C
Partner: UNT Libraries Government Documents Department

The distribution of subsurface damage in fused silica

Description: Managing subsurface damage during the shaping process and removing subsurface damage during the polishing process is essential in the production of low damage density optical components, such as those required for use on high peak power lasers. Removal of subsurface damage, during the polishing process, requires polishing to a depth which is greater than the depth of the residual cracks present following the shaping process. To successfully manage, and ultimately remove subsurface damage, understanding the distribution and character of fractures in the subsurface region introduced during fabrication process is important. We have characterized the depth and morphology of subsurface fractures present following fixed abrasive and loose abrasive grinding processes. At shallow depths lateral cracks and an overlapping series of trailing indentation fractures were found to be present. At greater depths, subsurface damage consists of a series of trailing indentation fractures. The area density of trailing fractures changes as a function of depth, however the length and shape of individual cracks remain nearly constant for a given grinding process. We have developed and applied a model to interpret the depth and crack length distributions of subsurface surface damage in terms of key variables including abrasive size and load.
Date: November 21, 2005
Creator: Miller, P E; Suratwala, T I; Wong, L L; Feit, M D; Menapace, J A; Davis, P J et al.
Partner: UNT Libraries Government Documents Department

Initial operating experience of the 12-MW La Ola photovoltaic system.

Description: The 1.2-MW La Ola photovoltaic (PV) power plant in Lanai, Hawaii, has been in operation since December 2009. The host system is a small island microgrid with peak load of 5 MW. Simulations conducted as part of the interconnection study concluded that unmitigated PV output ramps had the potential to negatively affect system frequency. Based on that study, the PV system was initially allowed to operate with output power limited to 50% of nameplate to reduce the potential for frequency instability due to PV variability. Based on the analysis of historical voltage, frequency, and power output data at 50% output level, the PV system has not significantly affected grid performance. However, it should be noted that the impact of PV variability on active and reactive power output of the nearby diesel generators was not evaluated. In summer 2011, an energy storage system was installed to counteract high ramp rates and allow the PV system to operate at rated output. The energy storage system was not fully operational at the time this report was written; therefore, analysis results do not address system performance with the battery system in place.
Date: October 1, 2011
Creator: Ellis, Abraham; Lenox, Carl (SunPower Corporation, Richmond, CA); Johnson, Jay; Quiroz, Jimmy Edward & Schenkman, Benjamin L.
Partner: UNT Libraries Government Documents Department

Characterization of Electron Beams in Multiple Welders Using the Enhanced Modified Faraday Cup

Description: Using the Enhanced Modified Faraday Cup (EMFC), the differences in the beams produced by two electron beam (EB) welders are characterized at different focus settings and work distances. For example, EMFC measurements show that sharply focused beams display different shapes and peak power densities which vary by nearly 20% for the same welding parameters on these two welders. Increases in work distance on each machine were shown to result in decreases in both the peak power density and the resulting weld size and shape. Because of the differences in machine performance, additional differences arise when comparing the welds produced by each machine. These different weld dimensions are attributed to differences in the beam shape and a 70 mm difference in the theoretical beam crossover location in the upper column of the two welders. The crossover location, which can not be physically measured, is determined using the EMFC by analyzing the beam distribution parameters of sharply focused beams over a range of work distances and can be used to explain the variation in the peak power densities of the two machines. Once the machines are characterized using this quantitative tool, changes in either the beam focus or work distance can be made to attain similar beams from different welders, thus providing a baseline for developing modern weld transfer procedures.
Date: August 1, 2006
Creator: Palmer, T A & Elmer, J W
Partner: UNT Libraries Government Documents Department

The prototype fundamental power coupler for the spallation neutron source superconducting cavities : design and initial test results /

Description: Each of the 805 MHz superconducting cavities of the Spallation Neutron Source (SNS) is powered via a coaxial Fundamental Power Coupler (FPC) with a 50 {Omega} impedance and a warm planar alumina window. The design is derived from the experience of other laboratories; in particular, a number of details are based on the coupler developed for the KEK B-Factory superconducting cavities. However, other design features have been modified to account for the fact that the SNS FPC will transfer a considerably lower average power than the KEK-B coupler. Four prototypes have been manufactured so far, and preliminary tests performed on two of them at Los Alamos National Laboratory (LANL). During these tests, peak powers of over 700 kW were transferred through the couplers in the test stand designed and built for this purpose. This paper gives details of the coupler design and of the results obtained from the RF tests on the test stand during the last few months. A more comprehensive set of tests is planned for the near future.
Date: January 1, 2001
Creator: Campisi, I. E.; Daly, E. F.; Davis, G. K.; Drury, M.; Henry, J. E.; Kneisel, P. et al.
Partner: UNT Libraries Government Documents Department

Coordination of Retail Demand Response with Midwest ISO Markets

Description: The Organization of Midwest ISO States (OMS) launched the Midwest Demand Resource Initiative (MWDRI) in 2007 to identify barriers to deploying demand response (DR) resources in the Midwest Independent System Operator (MISO) region and develop policies to overcome them. The MWDRI stakeholders decided that a useful initial activity would be to develop more detailed information on existing retail DR programs and dynamic pricing tariffs, program rules, and utility operating practices. This additional detail could then be used to assess any"seams issues" affecting coordination and integration of retail DR resources with MISO's wholesale markets. Working with state regulatory agencies, we conducted a detailed survey of existing DR programs, dynamic pricing tariffs, and their features in MISO states. Utilities were asked to provide information on advance notice requirements to customers, operational triggers used to call events (e.g. system emergencies, market conditions, local emergencies), use of these DR resources to meet planning reserves requirements, DR resource availability (e.g., seasonal, annual), participant incentive structures, and monitoring and verification (M&V) protocols. This report describes the results of this comprehensive survey and discusses policy implications for integrating legacy retail DR programs and dynamic pricing tariffs into organized wholesale markets. Survey responses from 37 MISO members and 4 non-members provided information on 141 DR programs and dynamic pricing tariffs with a peak load reduction potential of 4,727 MW of retail DR resource. Major findings of this study area:- About 72percent of available DR is from interruptible rate tariffs offered to large commercial and industrial customers, while direct load control (DLC) programs account for ~;;18percent. Almost 90percent of the DR resources included in this survey are provided by investor-owned utilities. - Approximately, 90percent of the DR resources are available with less than two hours advance notice and over 1,900 MW can be dispatched on less than thirty minutes ...
Date: May 27, 2008
Creator: Bharvirkar, Ranjit; Bharvirkar, Ranjit; Goldman, Charles; Heffner, Grayson & Sedano, Richard
Partner: UNT Libraries Government Documents Department

Demonstration of Smart Building Controls to Manage Building Peak Loads: Innovative Non-Wires Technologies

Description: As a part of the non-wires solutions effort, BPA in partnership with Pacific Northwest National Laboratory (PNNL) is exploring the use of two distributed energy resources (DER) technologies in the City of Richland. In addition to demonstrating the usefulness of the two DER technologies in providing peak demand relief, evaluation of remote direct load control (DLC) is also one of the primary objectives of this demonstration. The concept of DLC, which is used to change the energy use profile during peak hours of the day, is not new. Many utilities have had success in reducing demand at peak times to avoid building new generation. It is not the need for increased generation that is driving the use of direct load control in the Northwest, but the desire to avoid building additional transmission capacity. The peak times at issue total between 50 and 100 hours a year. A transmission solution to the problem would cost tens of millions of dollars . And since a ?non wires? solution is just as effective and yet costs much less, the capital dollars for construction can be used elsewhere on the grid where building new transmission is the only alternative. If by using DLC, the electricity use can be curtailed, shifted to lower use time periods or supplemented through local generation, the existing system can be made more reliable and cost effective.
Date: December 22, 2004
Creator: Katipamula, Srinivas & Hatley, Darrel D.
Partner: UNT Libraries Government Documents Department

Superconducting RF for Direct Acceleration in TeV Colliders

Description: The extensive effort by many of the world's best accelerator personnel which has been required for the commissioning of the SLC shows that pushing the SLC design parameters further will be extraordinarily difficult, if not impossible.Use of parameters which are equal to or less restrictive than those of the SLC, together with large-scale application of superconducting cavity gradients which have been achieved on a small scale, makes a 2 TeV e^+e^- collider worthy of consideration.The low peak power required to fill a high Q cavity and a high ratio of higher order mode damping rate to fundamental power dissipation make a linac using superconducting RF accelerating cavities and periodic bunch trains a potentially viable solution.
Date: October 1, 1988
Creator: Sundelin, Ronald
Partner: UNT Libraries Government Documents Department

High power testing of the 402.5 MHZ and 805 MHZ RF windows for the spallation neutron source accelerator

Description: Hisorically, Radio Frequency (RF) windows have been a common point of failure in input power couplers; therefore, reliable RF windows are critical to the success of the Spallation Neutron Source (SNS) project. The normal conducting part of the SNS accelerator requires six RF windows at 402.5 MHz and eight RF windows at 805 MHz[l]. Each RF window will transmit up to 180 kW of average power and 2.5 MW peak power at 60 Hz with 1.2 millisecond pulses. The RF windows, designed and manufactured by Thales, were tested at the full average power for 4 hours to ensure no problems with the high average power and then tested to an effective forward power level of 10 MW by testing at 2.5 MW forward power into a short and varying the phase of the standing wave. The sliding short was moved from 0 to 180 degrees to ensure no arcing or breakdown problems occur in any part of the window. This paper discusses the results of the high power testing of both the 402.5 MHz and the 805 MHz RF windows. Problems encountered during testing and the solutions for these problems are discussed.
Date: January 1, 2003
Creator: Cummings, K. A. (Karen Ann); De Baca, J. M. (John M.); Harrison, J. S. (John S.); Rodriguez, M. B. (Manuelita B.); Torrez, P. A. (Phillip A.) & Warner, D. K. (David K.)
Partner: UNT Libraries Government Documents Department

Double-passed, high-energy quasi-phase-matched optical parametric chirped-pulse amplifier

Description: Quasi-phase-matched (QPM) optical parametric chirped-pulse amplification (OPCPA) in periodically poled materials such as periodically poled LiNbO{sub 3} (PPLN) and periodically poled KTiOPO{sub 4} (PPKTP) has been shown to exhibit advantages over the OPCPA in bulk nonlinear crystals. [GHH98, RPN02] The use of the maximum material nonlinear coefficient results in ultra-high gain with low pump peak power. Furthermore, propagation of signal, pump, and idler beams along one of the crystal principal axes eliminates the birefringent walk-off, reduces angular sensitivity, and improves beam quality. Relatively high level of parasitic parametric fluorescence (PF) in QPM OPCPA represents an impediment for simple, single-stage, high-gain amplification of optical pulses from nJ to mJ energies. PF in QPM is increased when compared to PF in critical phase matching in bulk crystals as a result of broader angular acceptance of the nonlinear conversion process. PF reduces prepulse contrast and conversion efficiency by competition with the signal pulse for pump pulse energy. Previous experiments with QPM OPCPA have thus resulted in pulse energies limited to tens of {mu}J. [JSE03] Optical parametric amplification of a narrowband signal pulse in PPKTP utilizing two pump beams has been demonstrated at a mJ-level, [FPK03] but the conversion efficiency has been limited by low energy extraction of pump pulse in the first pass of amplification. Additionally, narrow spectral bandwidth was the result of operation far from signal-idler degeneracy. Here we present a novel double-pass, broad-bandwidth QPM OPCPA. 1.2 mJ of amplified signal energy is produced in a single PPKTP crystal utilizing a single 24-mJ pump pulse from a commercial pump laser. [JFE05] To our knowledge, this is the highest energy demonstrated in QPM OPCPA. Double-passed QPM OPCPA exhibits high gain (> 3 x 10{sup 6}), high prepulse contrast (> 3 x 10{sup 7}), high energy stability (3% rms), and excellent beam quality. We ...
Date: September 19, 2005
Creator: Jovanovic, I; Forget, N; Brown, C G; Ebbers, C A; Blanc, C L & Barty, C J
Partner: UNT Libraries Government Documents Department

Supply Curves of Conserved Energy

Description: Supply curves of conserved energy provide an accounting framework that expresses the potential for energy conservation. The economic worthiness of a conservation measure is expressed in terms of the cost of conserved energy, and a measure is considered economical when the cost of conserved energy is less than the price of the energy it replaces. A supply curve of conserved energy is independent of energy prices; however, the economical reserves of conserved energy will depend on energy prices. Double-counting of energy savings and error propagation are common problems when estimating conservation potentials, but supply curves minimize these difficulties and make their consequences predictable. The sensitivity of the cost of conserved energy is examined, as are variations in the optimal investment strategy in response to changes in inputs. Guidelines are presented for predicting the consequences of such changes. The conservation supply curve concept can be applied to peak power, water, pollution, and other markets where consumers demand a service rather than a particular good.
Date: May 1, 1982
Creator: Meier, Alan Kevin
Partner: UNT Libraries Government Documents Department

Demand Responsive and Energy Efficient Control Technologies andStrategies in Commercial Buildings

Description: Commercial buildings account for a large portion of summer peak electric demand. Research results show that there is significant potential to reduce peak demand in commercial buildings through advanced control technologies and strategies. However, a better understanding of commercial buildings contribution to peak demand and the use of energy management and control systems is required to develop this demand response resource to its full potential. The main objectives of the study were: (1) To evaluate the size of contributions of peak demand commercial buildings in the U.S.; (2) To understand how commercial building control systems support energy efficiency and DR; and (3) To disseminate the results to the building owners, facility managers and building controls industry. In order to estimate the commercial buildings contribution to peak demand, two sources of data are used: (1) Commercial Building Energy Consumption Survey (CBECS) and (2) National Energy Modeling System (NEMS). These two sources indicate that commercial buildings noncoincidental peak demand is about 330GW. The project then focused on technologies and strategies that deliver energy efficiency and also target 5-10% of this peak. Based on a building operations perspective, a demand-side management framework with three main features: (1) daily energy efficiency, (2) daily peak load management and (3) dynamic, event-driven DR are outlined. A general description of DR, its benefits, and nationwide DR potential in commercial buildings are presented. Case studies involving these technologies and strategies are described. The findings of this project are shared with building owners, building controls industry, researchers and government entities through a webcast and their input is requested. Their input is presented in the appendix section of this report.
Date: September 1, 2006
Creator: Piette, Mary Ann & Kiliccote, Sila
Partner: UNT Libraries Government Documents Department

High-power vacuum window in WR10

Description: Results are presented for fabrication and test of a WR10 waveguide window, for use in ultra-high vacuum at 91.4 GHz. Low-power bench measurements are compared with analytic and simulation results. Operation at approximately equal to 4-kW peak power, duty factor 10{sup {minus}6} and 10{sup {minus}9}-scale vacuum is noted.
Date: June 28, 1999
Creator: Hill, Marc E
Partner: UNT Libraries Government Documents Department

End-use load control for power system dynamic stability enhancement

Description: Faced with the prospect of increasing utilization of the transmission and distribution infrastructure without significant upgrade, the domestic electric power utility industry is investing heavily in technologies to improve network dynamic performance through a program loosely referred to as Flexible AC Transmission System (FACTS). Devices exploiting recent advances in power electronics are being installed in the power system to offset the need to construct new transmission lines. These devices collectively represent investment potential of several billion dollars over the next decade. A similar development, designed to curtail the peak loads and thus defer new transmission, distribution, and generation investment, falls under a category of technologies referred to as demand side management (DSM). A subset of broader conservation measures, DSM acts directly on the load to reduce peak consumption. DSM techniques include direct load control, in which a utility has the ability to curtail specific loads as conditions warrant. A novel approach has been conceived by Pacific Northwest National Laboratory (PNNL) to combine the objectives of FACTS and the technologies inherent in DSM to provide a distributed power system dynamic controller. This technology has the potential to dramatically offset major investments in FACTS devices by using direct load control to achieve dynamic stability objectives. The potential value of distributed versus centralized grid modulation has been examined by simulating the western power grid under extreme loading conditions. In these simulations, a scenario is analyzed in which active grid stabilization enables power imports into the southern California region to be increased several hundred megawatts beyond present limitations. Modeling results show distributed load control is up to 30 percent more effective than traditional centralized control schemes in achieving grid stability.
Date: February 1, 1997
Creator: Dagle, J. E.; Winiarski, D. W. & Donnelly, M. K.
Partner: UNT Libraries Government Documents Department