WorldWideScience

Sample records for high-power high-gain applications

  1. High Power Diode Lasers Technology and Applications

    CERN Document Server

    Bachmann, Friedrich; Poprawe, Reinhart

    2007-01-01

    In a very comprehensive way this book covers all aspects of high power diode laser technology for materials processing. Basics as well as new application oriented results obtained in a government funded national German research project are described in detail. Along the technological chain after a short introduction in the second chapter diode laser bar technology is discussed regarding structure, manufacturing technology and metrology. The third chapter illuminates all aspects of mounting and cooling, whereas chapter four gives wide spanning details on beam forming, beam guiding and beam combination, which are essential topics for incoherently coupled multi-emitter based high power diode lasers. Metrology, standards and safety aspects are the theme of chapter five. As an outcome of all the knowledge from chapter two to four various system configurations of high power diode lasers are described in chapter six; not only systems focussed on best available beam quality but especially also so called "modular" set...

  2. High-power optics lasers and applications

    CERN Document Server

    Apollonov, Victor V

    2015-01-01

    This book covers the basics, realization and materials for high power laser systems and high power radiation interaction with  matter. The physical and technical fundamentals of high intensity laser optics and adaptive optics and the related physical processes in high intensity laser systems are explained. A main question discussed is: What is power optics? In what way is it different from ordinary optics widely used in cameras, motion-picture projectors, i.e., for everyday use? An undesirable consequence of the thermal deformation of optical elements and surfaces was discovered during studies of the interaction with powerful incident laser radiation. The requirements to the fabrication, performance and quality of optical elements employed within systems for most practical applications are also covered. The high-power laser performance is generally governed by the following: (i) the absorption of incident optical radiation (governed primarily by various absorption mechanisms), (ii) followed by a temperature ...

  3. Innovations in high power fiber laser applications

    Science.gov (United States)

    Beyer, Eckhard; Mahrle, Achim; Lütke, Matthias; Standfuss, Jens; Brückner, Frank

    2012-02-01

    Diffraction-limited high power lasers represent a new generation of lasers for materials processing, characteristic traits of which are: smaller, cost-effective and processing "on the fly". Of utmost importance is the high beam quality of fiber lasers which enables us to reduce the size of the focusing head incl. scanning mirrors. The excellent beam quality of the fiber laser offers a lot of new applications. In the field of remote cutting and welding the beam quality is the key parameter. By reducing the size of the focusing head including the scanning mirrors we can reach scanning frequencies up to 1.5 kHz and in special configurations up to 4 kHz. By using these frequencies very thin and deep welding seams can be generated experienced so far with electron beam welding only. The excellent beam quality of the fiber laser offers a high potential for developing new applications from deep penetration welding to high speed cutting. Highly dynamic cutting systems with maximum speeds up to 300 m/min and accelerations up to 4 g reduce the cutting time for cutting complex 2D parts. However, due to the inertia of such systems the effective cutting speed is reduced in real applications. This is especially true if complex shapes or contours are cut. With the introduction of scanner-based remote cutting systems in the kilowatt range, the effective cutting speed on the contour can be dramatically increased. The presentation explains remote cutting of metal foils and sheets using high brightness single mode fiber lasers. The presentation will also show the effect of optical feedback during cutting and welding with the fiber laser, how those feedbacks could be reduced and how they have to be used to optimize the cutting or welding process.

  4. A Broadband and High Gain Tapered Slot Antenna for W-Band Imaging Array Applications

    Directory of Open Access Journals (Sweden)

    Dong Sik Woo

    2014-01-01

    Full Text Available A broadband and high gain tapered slot antenna (TSA by utilizing a broadband microstrip- (MS- to-coplanar stripline (CPS balun has been developed for millimeter-wave imaging systems and sensors. This antenna exhibits ultrawideband performance for frequency ranges from 70 to over 110 GHz with the high antenna gain, low sidelobe levels, and narrow beamwidth. The validity of this antenna as imaging arrays is also demonstrated by analyzing mutual couplings and 4-element linear array. This antenna can be applied to mm-wave phased array, imaging array for plasma diagnostics applications.

  5. Highly efficient multifunctional metasurface for high-gain lens antenna application

    Science.gov (United States)

    Hou, Haisheng; Wang, Guangming; Li, Haipeng; Guo, Wenlong; Li, Tangjing

    2017-07-01

    In this paper, a novel multifunctional metasurface combining linear-to-circular polarization conversion and electromagnetic waves focusing has been proposed and applied to design a high-gain lens antenna working at Ku band. The multifunctional metasurface consists of 15 × 15 unit cells. Each unit cell is composed of four identical metallic layers and three intermediate dielectric layers. Due to well optimization, the multifunctional metasurface can convert the linearly polarized waves generated by the source to circularly polarized waves and focus the waves. By placing a patch antenna operating at 15 GHz at the focal point of the metasurface and setting the focal distance to diameter ratio ( F/ D) to 0.34, we obtain a multifunctional lens antenna. Simulated and measured results coincide well, indicating that the metasurface can convert linearly polarized waves to right-handed circularly polarized waves at 15 GHz with excellent performances in terms of the 3 dB axial ratio bandwidth of 5.3%, realized gain of 16.9 dB and aperture efficiency of 41.2%. Because of the advantages of high gain, competitive efficiency and easy fabrication, the proposed lens antenna has a great potential application in wireless and satellite communication.

  6. High Efficiency Power Converter for Low Voltage High Power Applications

    DEFF Research Database (Denmark)

    Nymand, Morten

    and maximum output power. In chapter 3, a detailed analysis of dominant loss factors in high power converters for low voltage applications is presented. The analysis concludes that: • Power transformers for low voltage high power, if properly designed, will have extremely low leakage inductance......The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based....... • If optimally designed, boost converters will be much more efficient than comparable buck type converters for high power low voltage applications. • The use of voltage clamp circuits to protect primary switches in boost converters is no longer needed for device protection. On the other hand...

  7. High Efficiency Power Converter for Low Voltage High Power Applications

    DEFF Research Database (Denmark)

    Nymand, Morten

    . A detailed analysis of dominant loss factors in high power converters for low voltage applications is presented. The analysis concludes that: • Power transformers for low voltage high power, if properly designed, will have extremely low leakage inductance. • If optimally designed, boost converters......The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based......, if a converter is properly designed, primary side voltage clamp circuits will not even work in low voltage high power converters. • Very high conversion efficiency can be achieved. Peak efficiency of 98% and worst case minimum efficiency of 96.8% are demonstrated on a 1.5 kW converter. The ability...

  8. High Power Fiber Lasers and Applications to Manufacturing

    Science.gov (United States)

    Richardson, Martin; McComb, Timothy; Sudesh, Vikas

    2008-09-01

    We summarize recent developments in high power fiber laser technologies and discuss future trends, particularly in their current and future use in manufacturing technologies. We will also describe our current research programs in fiber laser development, ultra-fast and new lasers, and will mention the expectations in these areas for the new Townes Laser Institute. It will focus on new core laser technologies and their applications in medical technologies, advanced manufacturing technologies and defense applications. We will describe a program on large mode area fiber development that includes results with the new gain-guiding approach, as well as high power infra-red fiber lasers. We will review the opportunities for high power fiber lasers in various manufacturing technologies and illustrate this with applications we are pursuing in the areas of femtosecond laser applications, advanced lithographies, and mid-IR technologies.

  9. Characteristics of trap-filled gallium arsenide photoconductive switches used in high gain pulsed power applications

    Energy Technology Data Exchange (ETDEWEB)

    ISLAM,N.E.; SCHAMILOGLU,E.; MAR,ALAN; LOUBRIEL,GUILLERMO M.; ZUTAVERN,FRED J.; JOSHI,R.P.

    2000-05-30

    The electrical properties of semi-insulating (SI) Gallium Arsenide (GaAs) have been investigated for some time, particularly for its application as a substrate in microelectronics. Of late this material has found a variety of applications other than as an isolation region between devices, or the substrate of an active device. High resistivity SI GaAs is increasingly being used in charged particle detectors and photoconductive semiconductor switches (PCSS). PCSS made from these materials operating in both the linear and non-linear modes have applications such as firing sets, as drivers for lasers, and in high impedance, low current Q-switches or Pockels cells. In the non-linear mode, it has also been used in a system to generate Ultra-Wideband (UWB) High Power Microwaves (HPM). The choice of GaAs over silicon offers the advantage that its material properties allow for fast, repetitive switching action. Furthermore photoconductive switches have advantages over conventional switches such as improved jitter, better impedance matching, compact size, and in some cases, lower laser energy requirement for switching action. The rise time of the PCSS is an important parameter that affects the maximum energy transferred to the load and it depends, in addition to other parameters, on the bias or the average field across the switch. High field operation has been an important goal in PCSS research. Due to surface flashover or premature material breakdown at higher voltages, most PCSS, especially those used in high power operation, need to operate well below the inherent breakdown voltage of the material. The lifetime or the total number of switching operations before breakdown, is another important switch parameter that needs to be considered for operation at high bias conditions. A lifetime of {approximately} 10{sup 4} shots has been reported for PCSS's used in UWB-HPM generation [5], while it has exceeded 10{sup 8} shots for electro-optic drivers. Much effort is currently

  10. High-power lasers for directed-energy applications.

    Science.gov (United States)

    Sprangle, Phillip; Hafizi, Bahman; Ting, Antonio; Fischer, Richard

    2015-11-01

    In this article, we review and discuss the research programs at the Naval Research Laboratory (NRL) on high-power lasers for directed-energy (DE) applications in the atmosphere. Physical processes affecting propagation include absorption/scattering, turbulence, and thermal blooming. The power levels needed for DE applications require combining a number of lasers. In atmospheric turbulence, there is a maximum intensity that can be placed on a target that is independent of the initial beam spot size and laser beam quality. By combining a number of kW-class fiber lasers, scientists at the NRL have successfully demonstrated high-power laser propagation in a turbulent atmosphere and wireless recharging. In the NRL experiments, four incoherently combined fiber lasers having a total power of 5 kW were propagated to a target 3.2 km away. These successful high-power experiments in a realistic atmosphere formed the basis of the Navy's Laser Weapon System. We compare the propagation characteristics of coherently and incoherently combined beams without adaptive optics. There is little difference in the energy on target between coherently and incoherently combined laser beams for multi-km propagation ranges and moderate to high levels of turbulence. Unlike incoherent combining, coherent combining places severe constraints on the individual lasers. These include the requirement of narrow power spectral linewidths in order to have long coherence times as well as polarization alignment of all the lasers. These requirements are extremely difficult for high-power lasers.

  11. A Lemon Cell Battery for High-Power Applications

    Science.gov (United States)

    Muske, Kenneth R.; Nigh, Christopher W.; Weinstein, Randy D.

    2007-04-01

    This article discusses the development of a lemon cell battery for high-power applications. The target application is the power source of a dc electric motor for a model car constructed by first-year engineering students as part of their introductory course design project and competition. The battery is composed of a series of lemon juice cells made from UV vis cuvets that use a magnesium anode and copper cathode. Dilution of the lemon juice to reduce the rate of corrosion of the magnesium anode and the addition of table salt to reduce the internal resistance of the cell are examined. Although our specific interest is the use of this lemon cell battery to run an electric dc motor, high-power applications such as radios, portable cassette or CD players, and other battery-powered toys are equally appropriate for demonstration and laboratory purposes using this battery.

  12. High-Power Electron Accelerators for Space (and other) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewellen, John W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-23

    This is a presentation on high-power electron accelerators for space and other applications. The main points covered are: electron beams for space applications, new designs of RF accelerators, high-power high-electron mobility transistors (HEMT) testing, and Li-ion battery design. In summary, the authors have considered a concept of 1-MeV electron accelerator that can operate up to several seconds. This concept can be extended to higher energy to produce higher beam power. Going to higher beam energy requires adding more cavities and solid-state HEMT RF power devices. The commercial HEMT have been tested for frequency response and RF output power (up to 420 W). Finally, the authors are testing these HEMT into a resonant load and planning for an electron beam test in FY17.

  13. Self-commutating converters for high power applications

    CERN Document Server

    Arrillaga, Jos; Watson, Neville R; Murray, Nicholas J

    2010-01-01

    For very high voltage or very high current applications, the power industry still relies on thyristor-based Line Commutated Conversion (LCC), which limits the power controllability to two quadrant operation. However, the ratings of self-commutating switches such as the Insulated-Gate Bipolar Transistor (IGBT) and Integrated Gate-Commutated Thyristor (IGCT), are reaching levels that make the technology possible for very high power applications. This unique book reviews the present state and future prospects of self-commutating static power converters for applications requiring either ultr

  14. Progress on high-power 808nm VCSELs and applications

    Science.gov (United States)

    Zhou, Delai; Seurin, Jean-Francois; Xu, Guoyang; Van Leeuwen, Robert; Miglo, Alexander; Wang, Qing; Kovsh, Alexey; Ghosh, Chuni

    2017-02-01

    High power 808nm semiconductor lasers are widely used for pumping neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal to produce high-brightness lasing at 1064nm. In addition, there are growing interest to use such high power 808nm lasers in the field of automotive infra-red (IR) illumination and medical aesthetic treatment. Vertical-cavity surface-emitting lasers (VCSELs) have emerged as a promising candidate and attracted increased interests for those applications, due to their combined advantages of high efficiency, low diverging circular beam, narrow emission spectrum with reduced temperature sensitivity, low-cost manufacturability, simpler coupling optics, and increased reliability, especially at high temperatures. They can emit very high power with very high power density as they can be conveniently configured into large two-dimensional arrays and modules of arrays. We report recent development on such high-power, high-efficiency 808nm VCSELs with industrial leading 55% power conversion efficiency (PCE). Top emitting VCSELs were grown by MOCVD and processed into single devices and 2D arrays using selective wet oxidation process and substrate removal technique for efficient current confinement and heat removal. Peak PCE of 51% and peak power of 800W were achieved from 5x5mm array, corresponding to peak power density of 4kW/cm2. Pumped with new generation of 2.3kW VCSEL module, Q-switched laser pulse energy at 1064nm reached 46.9mJ, more than doubled from previously reported results.

  15. High-power diode lasers and their direct industrial applications

    Science.gov (United States)

    Loosen, Peter; Treusch, Hans-Georg; Haas, C. R.; Gardenier, U.; Weck, Manfred; Sinnhoff, V.; Kasperowski, S.; vor dem Esche, R.

    1995-04-01

    The paper summarizes activities of the two Fraunhofer-Institutes ILT and IPT concerning the development of high-power laser-diode stacks and their direct industrial applications. With microchannel coolers in copper technology and ultra-precision machined micro-optics a stack of 330 - 400 W total power with a maximum intensity of the focused beam of 2 104 W/cm2 has been built and tested in first applications. By further improvements of the lens-fabrication and -alignment technology as well as increase of the number of stacked diodes an output power in the kW-range and intensities up to about 105 W/cm2 shall be achieved in the near future. Applications of such laser sources in surface technology, in the processing of plastics, in laser-assisted machining and in brazing are discussed.

  16. High power ring methods and accelerator driven subcritical reactor application

    Energy Technology Data Exchange (ETDEWEB)

    Tahar, Malek Haj [Univ. of Grenoble (France)

    2016-08-07

    transverse beam dynamics. The results obtained allow to develop a correction scheme to minimize the tune variations of the FFAG. This is the cornerstone of a new fixed tune non-scaling FFAG that represents a potential candidate for high power applications. As part of the developments towards high power at the KURRI FFAG, beam dynamics studies have to account for space charge effects. In that framework, models have been installed in the tracking code ZGOUBI to account for the self-interaction of the particles in the accelerator. Application to the FFAG studies is shown. Finally, one focused on the ADSR concept as a candidate to solve the problem of nuclear waste. In order to establish the accelerator requirements, one compared the performance of ADSR with other conventional critical reactors by means of the levelized cost of energy. A general comparison between the different accelerator technologies that can satisfy these requirements is finally presented. In summary, the main drawback of the ADSR technology is the high Levelized Cost Of Energy compared to other advanced reactor concepts that do not employ an accelerator. Nowadays, this is a show-stopper for any industrial application aiming at producing energy (without dealing with the waste problem). Besides, the reactor is not intrinsically safer than critical reactor concepts, given the complexity of managing the target interface between the accelerator and the reactor core.

  17. High-power pump diodes for defense applications

    Science.gov (United States)

    Ebert, Chris; Guiney, Tina; Braker, Joe; Stapleton, Dean; Alegria, Kim; Irwin, David

    2017-05-01

    DILAS offers a variety of high power pump diode lasers, optimized for different gain media. Systems optimized for DPAL pumping at 766nm will be discussed, including results demonstrating precise wavelength and spectral width control necessary to optimal overlap with atomic lines. In addition, pump modules optimized at 793 nm for Tm fiber laser pumping have been demonstrated, including a low SWaP module targeted for airborne applications. Lastly, DILAS' line of high-efficiency/low-SWaP pump at 976nm for Yb fiber laser will be presented. Starting with the 330W IS46 module, DILAS has demonstrated >53% efficiency, and has now increased brightness up to 625W from a 225 um/ 0.22 NA fiber. Developments towards a module with >900W output power will also be shown.

  18. Advanced Capacitors for High-Power Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — As the consumer and industrial requirements for compact, high-power-density, electrical power systems grow substantially over the next decade; there will be a...

  19. High-power green diode laser systems for biomedical applications

    DEFF Research Database (Denmark)

    Müller, André

    in conjunction with optical coherence tomography, two-photon microscopy or coherent anti-Stokes Raman scattering microscopy. In order to provide high-power green diode laser emission, nonlinear frequency conversion of state-of-the-art near-infrared diode lasers represents a necessary means. However, the obtained....... The underlying principle is spectral beam combining of multiple, comparable diode lasers with subsequent nonlinear frequency conversion. In the former approach multiple lasers are incoherently combined with an external optical component. With two 1062 nm tapered diode lasers and a reflecting volume Bragg grating...

  20. Active Photonic crystal fibers for high power applications

    DEFF Research Database (Denmark)

    Olausson, Christina Bjarnal Thulin

    . This plays an important role in high power lasers and ampliers with respect to efficiency, packaging, and thermal handling. The third part of the work has involved developing tools for characterizing the mode quality and stability of large core bers. Stable, single-mode bers with larger cores are essential...... records have been set using this ber. An output power of 167 W has been achieved, which, at the time of writing, is the highest output power generated from ytterbium bers in this wavelength region and from photonic bandgap bers in general. The 1178 nm light has subsequently been frequency doubled to 589...

  1. High-power lasers for directed-energy applications: comment.

    Science.gov (United States)

    Vorontsov, Mikhail A; Weyrauch, Thomas

    2016-12-10

    Sprangle et al. [Appl. Opt.54, F201 (2015)APOPAI0003-693510.1364/AO.54.00F201] recently concluded that our experiments on coherent combining of laser beams over an atmospheric path [Opt. Lett.36, 4455 (2011)OPLEDP0146-959210.1364/OL.36.004455] were "effective only because at these low-power levels the linewidth of the lasers was very narrow… and the level of atmospheric turbulence was low…." These conclusions are inaccurate, not relevant to practical high-power coherently combined laser systems, and contradict our most recent experiments with coherent combining of 21 laser beams with a linewidth of about 1 GHz over 7 km distance. In this comment we also challenge the major conclusion of Sprangle et al. [Appl. Opt.54, F201 (2015)APOPAI0003-693510.1364/AO.54.00F201] and the more recently published paper by Nelson et al. [Appl. Opt.55, 1757 (2016)APOPAI0003-693510.1364/AO.55.001757] regarding inefficiency of coherent beam combining under typical atmospheric conditions.

  2. High-Power Density SOFCs for Aviation Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — As solid oxide fuel cells (SOFCs) approach commercialization, interest in broader applications of this technology is mounting. While the first commercialized systems...

  3. Advantages and disadvantages of high power ultrasound application in the dairy industry

    National Research Council Canada - National Science Library

    Mislav Muža; Verica Batur; Marija Badanjak; Zoran Herceg; Vesna Lelas; Anet Režek Jambrak

    2009-01-01

    .... In the last five years, new applications of high power ultrasound (HPU) include inactivation of enzymes and microorganisms, assistance in membrane processes, improvement of dairy product texture, improvement of functional properties...

  4. High power VCSEL devices for atomic clock applications

    Science.gov (United States)

    Watkins, L. S.; Ghosh, C.; Seurin, J.-F.; Zhou, D.; Xu, G.; Xu, B.; Miglo, A.

    2015-09-01

    We are developing VCSEL technology producing >100mW in single frequency at wavelengths 780nm, 795nm and 850nm. Small aperture VCSELs with few mW output have found major applications in atomic clock experiments. Using an external cavity three-mirror configuration we have been able to operate larger aperture VCSELs and obtain >70mW power in single frequency operation. The VCSEL has been mounted in a fiber pigtailed package with the external mirror mounted on a shear piezo. The package incorporates a miniature Rb cell locker to lock the VCSEL wavelength. This VCSEL operates in single frequency and is tuned by a combination of piezo actuator, temperature and current. Mode-hop free tuning over >30GHz frequency span is obtained. The VCSEL has been locked to the Rb D2 line and feedback control used to obtain line-widths of <100kHz.

  5. High-gain dipole antenna using polydimethylsiloxane-glass microsphere (PDMS-GM) substrate for 5G applications

    Science.gov (United States)

    Muhamad, Wan Asilah Wan; Ngah, Razali; Jamlos, Mohd Faizal; Soh, Ping Jack; Ali, Mohd Tarmizi

    2017-01-01

    A new dipole antenna designed using polydimethylsiloxane-glass microsphere (PDMS-GM) substrate is presented. The PDMS-GM substrate offered a lower permittivity of 1.85 compared to pure PDMS of 2.7. This resulted in a wide operating frequency range from 19 GHz up to more than 45 GHz, indicating a bandwidth of more than 28 GHz. The proposed PDMS-GM antenna featured a gain of up to 13.3 dB compared to pure PDMS which only produced 13 GHz of bandwidth and 5.5 dB gain. Instead of wide bandwidth and high gain, the proposed antenna is capable of becoming water resistant by covering its radiator and SMA connector. Such capabilities of the new PDMS-GM antenna indicated suitability for the fifth-generation (5G) wireless communication systems.

  6. Sensor fault detection and isolation via high-gain observers: application to a double-pipe heat exchanger.

    Science.gov (United States)

    Escobar, R F; Astorga-Zaragoza, C M; Téllez-Anguiano, A C; Juárez-Romero, D; Hernández, J A; Guerrero-Ramírez, G V

    2011-07-01

    This paper deals with fault detection and isolation (FDI) in sensors applied to a concentric-pipe counter-flow heat exchanger. The proposed FDI is based on the analytical redundancy implementing nonlinear high-gain observers which are used to generate residuals when a sensor fault is presented (as software sensors). By evaluating the generated residual, it is possible to switch between the sensor and the observer when a failure is detected. Experiments in a heat exchanger pilot validate the effectiveness of the approach. The FDI technique is easy to implement allowing the industries to have an excellent alternative tool to keep their heat transfer process under supervision. The main contribution of this work is based on a dynamic model with heat transfer coefficients which depend on temperature and flow used to estimate the output temperatures of a heat exchanger. This model provides a satisfactory approximation of the states of the heat exchanger in order to allow its implementation in a FDI system used to perform supervision tasks. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  7. High-power random distributed feedback fiber laser: From science to application

    Energy Technology Data Exchange (ETDEWEB)

    Du, Xueyuan [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Naval Academy of Armament, Beijing 100161 (China); Zhang, Hanwei; Xiao, Hu; Ma, Pengfei; Wang, Xiaolin; Zhou, Pu; Liu, Zejin [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2016-10-15

    A fiber laser based on random distributed feedback has attracted increasing attention in recent years, as it has become an important photonic device and has found wide applications in fiber communications or sensing. In this article, recent advances in high-power random distributed feedback fiber laser are reviewed, including the theoretical analyses, experimental approaches, discussion on the practical applications and outlook. It is found that a random distributed feedback fiber laser can not only act as an information photonics device, but also has the feasibility for high-efficiency/high-power generation, which makes it competitive with conventional high-power laser sources. In addition, high-power random distributed feedback fiber laser has been successfully applied for midinfrared lasing, frequency doubling to the visible and high-quality imaging. It is believed that the high-power random distributed feedback fiber laser could become a promising light source with simple and economic configurations. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Three-phase multilevel inverter configuration for open-winding high power application

    DEFF Research Database (Denmark)

    Sanjeevikumar, Padmanaban; Blaabjerg, Frede; Wheeler, Patrick William

    2015-01-01

    This paper work exploits a new dual open-winding three-phase multilevel inverter configuration suitable for high power medium-voltage applications. Modular structure comprised of standard three-phase voltage source inverter (VSI) along with one additional bi-directional semiconductor device (MOSF...

  9. High Power Density and High Temperature Converter Design for Transportation Applications

    OpenAIRE

    Wang, Ruxi

    2012-01-01

    The continual development of high-power-density power electronic converters is driven particularly by modern transportation applications like electrical vehicles and more electric aircraft where the space and carrier capability is limited. However, there are several challenges related to transportation applications such as fault tolerance for safety concern, high temperature operation in extreme environments and more strict electromagnetic compatibility requirement. These challenges will incr...

  10. High power lasers and their industrial applications; Proceedings of the Meeting, Innsbruck, Austria, Apr. 15-18, 1986

    Science.gov (United States)

    Schuoecker, Dieter

    1986-01-01

    Papers are presented on the discharge behavior of an RF excited high power CO2 laser at different excitation frequencies; high power CO2 lasers for materials processing; a semiconductive preionization technique; high power Nd lasers for industrial applications; high power light transmission in optical waveguides; beam delivery systems for high power lasers; and quality control for high power CO2 laser optics. Topics discussed include the monitoring of laser material processes; measuring the quality of high power laser beams; the physics of laser material processing; metal precision drilling with lasers; and the evolution of microstructure for laser clad Fe-Cr-Mn-C alloys. Consideration is given to robotic manipulation for laser processing; laser cutting; the use of the laser versus the electron beam in welding the surface treatments; high power laser safety; and laser protective filters for the visible and near-IR spectrum.

  11. Monocrystalline CVD-diamond optics for high-power laser applications

    Science.gov (United States)

    Holly, C.; Traub, M.; Hoffmann, D.; Widmann, C.; Brink, D.; Nebel, C.; Gotthardt, T.; Sözbir, M. C.; Wenzel, C.

    2016-03-01

    The potential of diamond as an optical material for high-power laser applications in the wavelength regime from the visible spectrum (VIS) to the near infrared (NIR) is investigated. Single-crystal diamonds with lateral dimensions up to 7×7mm2 are grown with microwave plasma assisted chemical vapor deposition (MPACVD) in parallel with up to 60 substrates and are further processed to spherical optics for beam guidance and shaping. The synthetic diamonds offer superior thermal, mechanical and optical properties, including low birefringence, scattering and absorption, also around 1 μm wavelength. We present dielectric (AR and HR) coated single-crystal diamond optics which are tested under high laser power in the multi-kW regime. The thermally induced focal shift of the diamond substrates is compared to the focal shift of a standard collimating and focusing unit for laser cutting made of fused silica optics. Due to the high thermal conductivity and low absorption of the diamond substrates compared to the fused silica optics no additional focal shift caused by a thermally induced refractive index change in the diamond is observed in our experiments. We present experimental results regarding the performance of the diamond substrates with and without dielectric coatings under high power and the influences of growth induced birefringence on the optical quality. Finally, we discuss the potential of the presented diamond lenses for high-power applications in the field of laser materials processing.

  12. Micro-scanning mirrors for high-power laser applications in laser surgery

    Science.gov (United States)

    Sandner, Thilo; Kimme, Simon; Grasshoff, Thomas; Todt, Ulrich; Graf, Alexander; Tulea, Cristian; Lenenbach, Achim; Schenk, Harald

    2014-03-01

    We present two novel micro scanning mirrors with large aperture and HR dielectric coatings suitable for high power laser applications in a miniaturized laser-surgical instrument for neurosurgery to cut skull tissue. An electrostatic driven 2D-raster scanning mirror with 5x7.1mm aperture is used for dynamic steering of a ps-laser beam of the laser cutting process. A second magnetic 2D-beam steering mirror enables a static beam correction of a hand guided laser instrument. Optimizations of a magnetic gimbal micro mirror with 6 mm x 8 mm mirror plate are presented; here static deflections of 3° were reached. Both MEMS devices were successfully tested with a high power ps-laser at 532nm up to 20W average laser power.

  13. Application of a High-Power Reversible Converter in a Hybrid Traction Power Supply System

    Directory of Open Access Journals (Sweden)

    Gang Zhang

    2017-03-01

    Full Text Available A high-power reversible converter can achieve a variety of functions, such as recovering regenerative braking energy, expanding traction power capacity, and improving an alternating current (AC grid power factor. A new hybrid traction power supply scheme, which consists of a high-power reversible converter and two 12-pulse diode rectifiers, is proposed. A droop control method based on load current feed-forward is adopted to realize the load distribution between the reversible converter and the existing 12-pulse diode rectifiers. The direct current (DC short-circuit characteristics of the reversible converter is studied, then the relationship between the peak fault current and the circuit parameters is obtained from theoretical calculations and validated by computer simulation. The first two sets of 2 MW reversible converters have been successfully applied in Beijing Metro Line 10, the proposed hybrid application scheme and coordinated control strategy are verified, and 11.15% of average energy-savings is reached.

  14. An overview of the reliability prediction related aspects of high power IGBTs in wind power applications

    DEFF Research Database (Denmark)

    Busca, Christian; Teodorescu, Remus; Blaabjerg, Frede

    2011-01-01

    Reliability is becoming more and more important as the size and number of installed Wind Turbines (WTs) increases. Very high reliability is especially important for offshore WTs because the maintenance and repair of such WTs in case of failures can be very expensive. WT manufacturers need...... to consider the reliability aspect when they design new power converters. By designing the power converter considering the reliability aspect the manufacturer can guarantee that the end product will ensure high availability. This paper represents an overview of the various aspects of reliability prediction...... of high power Insulated Gate Bipolar Transistors (IGBTs) in the context of wind power applications. At first the latest developments and future predictions about wind energy are briefly discussed. Next the dominant failure mechanisms of high power IGBTs are described and the most commonly used lifetime...

  15. Advantages and disadvantages of high power ultrasound application in the dairy industry

    Directory of Open Access Journals (Sweden)

    Mislav Muža

    2009-12-01

    Full Text Available Preservation of food with thermal sterilisation is usually the most common way nowadays. Besides the positive aim of preservation regarding microorganisms’ reduction, elevated temperature in processing simultaneously causes serious changes in nutritive and organoleptical properties of food. Loss of food quality is related to structure and texture deformations, modification of macromolecules and creation of new compounds coming from reactions that are catalised with temperature. One of the new non-thermal processes that can in large scale improve different processes in food industry is ultrasound. In the last five years, new applications of high power ultrasound (HPU include inactivation of enzymes and microorganisms, assistance in membrane processes, improvement of dairy product texture, improvement of functional properties of proteins etc. High power ultrasound application is used in emulsification and milk homogenization, but in these processes the most important thing is to monitor possible negative effect like oxidation of fats, inactivation of valuable enzymes and denaturation of proteins. Controled and optimized application of ultrasound demands application of specific ultrasound frequency and optimal treatment time. Treatments should be performed at lower temperatures to avoid negative side effects on treated materials.

  16. A scheme for a high-power, low-cost transmitter for deep space applications

    Science.gov (United States)

    Scheffer, L. K.

    2005-10-01

    Applications such as planetary radars and spacecraft communications require transmitters with extremely high effective isotropic radiated power. Until now, this has been done by combining a high-power microwave source with a large reflective antenna. However, this arrangement has a number of disadvantages. It is costly, since the steerable reflector alone is quite expensive, and for spacecraft communications, the need to transmit hurts the receive performance. For planetary radars, the utilization is very low since the antenna must be shared with other applications such as radio astronomy or spacecraft communications. This paper describes a potential new way of building such transmitters with lower cost, greater versatility, higher reliability, and potentially higher power. The basic idea is a phased array with a very large number of low-power elements, built with mass production techniques that have been optimized for consumer markets. The antennas are built en mass on printed circuit boards and are driven by chips, built with consumer complementary metal-oxide-semiconductor technology, that adjust the phase of each element. Assembly and maintenance should be comparatively inexpensive since the boards need only be attached to large, flat, unmoving, ground-level infrastructure. Applications to planetary radar and spacecraft communications are examined. Although we would be unlikely to use such a facility in this way, an implication for Search for Extraterrestrial Intelligence (SETI) is that high-power beacons are easier to build than had been thought.

  17. Fiber Optic Cables for Transmission of High-Power Laser Pulses in Spaceflight Applications

    Science.gov (United States)

    Thomes, W. J., Jr.; Ott, M. N.; Chuska, R. F.; Switzer, R. C.; Blair, D. E.

    2010-01-01

    Lasers with high peak power pulses are commonly used in spaceflight missions for a wide range of applications, from LIDAR systems to optical communications. Due to the high optical power needed, the laser has to be located on the exterior of the satellite or coupled through a series of free space optics. This presents challenges for thermal management, radiation resistance, and mechanical design. Future applications will require multiple lasers located close together, which further complicates the design. Coupling the laser energy into a fiber optic cable allows the laser to be relocated to a more favorable position on the spacecraft. Typical fiber optic termination procedures are not sufficient for injection of these high-power laser pulses without catastrophic damage to the fiber endface. In the current study, we will review the causes of fiber damage during high-power injection and discuss our new manufacturing procedures that overcome these issues to permit fiber use with high reliability in these applications. We will also discuss the proper methods for launching the laser pulses into the fiber to avoid damage and how this is being implemented for current spaceflight missions.

  18. Progress on high-power high-brightness VCSELs and applications

    Science.gov (United States)

    Zhou, Delai; Seurin, Jean-Francois; Xu, Guoyang; Zhao, Pu; Xu, Bing; Chen, Tong; Van Leeuwen, Robert; Matheussen, Joseph; Wang, Qing; Ghosh, Chuni

    2015-03-01

    Vertical-cavity surface-emitting lasers (VCSELs) are attractive for many pumping and direct-diode applications due to combined advantages in low cost, high reliability, narrow and thermally stable spectrum, high power scalability, and easy system integration, etc. We report our progress on electrically pumped, GaAs-based, high- power high-brightness VCSELs and 2D arrays in the infrared wavelength range. At 976nm, over 5.5W peak CW output and 60% peak power conversion efficiency (PCE) were demonstrated with 225um oxide-confined device. For 5x5mm arrays, peak PCE of 54% and peak power of >450W at 976nm, peak PCE of 46% and peak power of >110W at 808nm were achieved respectively under QCW conditions. External cavity configuration was used to improve the VCSEL brightness. Single mode output of 280mW and 37% PCE were realized from 80um device. For large 325um device, we obtained single mode (M2=1.1) CW output of 2.1W, corresponding to a brightness of 160MW/cm2*sr. Three major areas of applications using such VCSELs are discussed: 1. High brightness fiber output; 2. High power, high efficiency green lasers from 2nd harmonic generation. 3.34W green output with 21.2% PCE were achieved; 3. Pumping solid state lasers for high energy pulse generation. We have demonstrated Q-switched pulses with 16.1mJ at 1064nm and 4.9mJ with 1W average power at 473nm.

  19. Development of Resonant Diplexers for high-power ECRH – Status, Applications, Plans

    Directory of Open Access Journals (Sweden)

    Kasparek W.

    2015-01-01

    Full Text Available The development of diplexers for ECRH has been pursued at a number of institutes because of their attractive variety of applications: Power combination, non-mechanical, electrically controlled switching (of combined beams between launchers with tens of kHz, and discrimination of low-power ECE signals from high-power ECRH is feasible. In a first part, this paper reports on plasma experiments with a ring resonator (Mk IIa at ASDEX Upgrade. Commissioning experiments on fast switching between two launchers for synchronous stabilization of neoclassical tearing modes, as well as in-line ECE measurements have been performed, and experimental issues and first results are discussed. A clear influence of the switching phase on the amplitude of the 3/2 NTM mode was measured, complete stabilization could, however, not be demonstrated yet mainly due to imperfect resonator control. Concepts for improved tracking of the diplexers to the gyrotron frequency are presented. In a second part, the design of diplexers with ring resonators matched to HE11 fields is briefly discussed; these devices can be connected to corrugated waveguides without any mode converters. A compact version (MQ IV is under investigation, which is compatible with the ITER ECRH system (170 GHz, 63.5 mm waveguide, vacuum tight casing, with the final goal of high-power tests at the 170 GHz gyrotron facility at JAEA in Naka, Japan. First low-power test results are presented.

  20. A New Very-High-Efficiency R4 Converter for High-Power Fuel Cell Applications

    DEFF Research Database (Denmark)

    Nymand, Morten; Andersen, Michael Andreas E.

    2009-01-01

    A new very high efficiency 10 kW isolated R4 boost converter for low-voltage high-power fuel cell applications is presented. Using a new concept for partially paralleling of isolated boost converters, only the critical high ac-current parts are paralleled. Four 2.5 kW power stages, consisting...... of fullbridge switching stages and power transformers, operate in parallel on primary side and in series on secondary side. Current sharing is guaranteed by series connection of transformer secondary windings and three small cascaded current balancing transformers on primary side. The detailed design of a 10 k......W prototype converter is presented. Input voltage range is 30-60 V and output voltage is 800 V. Test results, including voltage- and current waveforms and efficiency measurements, are presented. A record high converter efficiency of 98.2 % is achieved. The proposed R4 boost converter thus constitutes a low...

  1. Interfacial electron and phonon scattering processes in high-powered nanoscale applications.

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, Patrick E.

    2011-10-01

    The overarching goal of this Truman LDRD project was to explore mechanisms of thermal transport at interfaces of nanomaterials, specifically linking the thermal conductivity and thermal boundary conductance to the structures and geometries of interfaces and boundaries. Deposition, fabrication, and post possessing procedures of nanocomposites and devices can give rise to interatomic mixing around interfaces of materials leading to stresses and imperfections that could affect heat transfer. An understanding of the physics of energy carrier scattering processes and their response to interfacial disorder will elucidate the potentials of applying these novel materials to next-generation high powered nanodevices and energy conversion applications. An additional goal of this project was to use the knowledge gained from linking interfacial structure to thermal transport in order to develop avenues to control, or 'tune' the thermal transport in nanosystems.

  2. High power fiber coupled diode lasers for display and lighting applications

    Science.gov (United States)

    Drovs, Simon; Unger, Andreas; Dürsch, Sascha; Köhler, Bernd; Biesenbach, Jens

    2017-02-01

    The performance of diode lasers in the visible spectral range has been continuously improved within the last few years, which was mainly driven by the goal to replace arc lamps in cinema or home projectors. In addition, the availability of such high power visible diode lasers also enables new applications in the medical field, but also the usage as pump sources for other solid state lasers. This paper summarizes the latest developments of fiber coupled sources with output power from 1.4 W to 120 W coupled into 100 μm to 400 μm fibers in the spectral range around 405 nm and 640 nm. New developments also include the use of fiber coupled multi single emitter arrays at 450 nm, as well as very compact modules with multi-W output power.

  3. High-power free-electron lasers-technology and future applications

    Science.gov (United States)

    Socol, Yehoshua

    2013-03-01

    Free-electron laser (FEL) is an all-electric, high-power, high beam-quality source of coherent radiation, tunable - unlike other laser sources - at any wavelength within wide spectral region from hard X-rays to far-IR and beyond. After the initial push in the framework of the “Star Wars” program, the FEL technology benefited from decades of R&D and scientific applications. Currently, there are clear signs that the FEL technology reached maturity, enabling real-world applications. E.g., successful and unexpectedly smooth commissioning of the world-first X-ray FEL in 2010 increased in one blow by more than an order of magnitude (40×) wavelength region available by FEL technology and thus demonstrated that the theoretical predictions just keep true in real machines. Experience of ordering turn-key electron beamlines from commercial companies is a further demonstration of the FEL technology maturity. Moreover, successful commissioning of the world-first multi-turn energy-recovery linac demonstrated feasibility of reducing FEL size, cost and power consumption by probably an order of magnitude in respect to previous configurations, opening way to applications, previously considered as non-feasible. This review takes engineer-oriented approach to discuss the FEL technology issues, keeping in mind applications in the fields of military and aerospace, next generation semiconductor lithography, photo-chemistry and isotope separation.

  4. Laser assisted die bending: a new application of high power diode lasers

    Science.gov (United States)

    Schuöcker, D.; Schumi, T.; Spitzer, O.; Bammer, F.; Schuöcker, G.; Sperrer, G.

    2015-02-01

    Nowadays high power lasers are mainly used for cutting of sheet metals, for welding, hardening and rapid prototyping. In the forming of sheet metals as bending or deep drawing lasers are not used. Nevertheless a few years ago a new application of high power lasers has been invented, where bending of materials that break at room temperature becomes possible by heating them along the bending edge with high power lasers thus allowing their treatment without cracks and rupture. For this purpose a large number of diode lasers are arranged in the bottom tool of a bending machine (a V-shaped die) which heat up the initially flat sheet metal during the bending process what is performed by pressing it into the die with a knife shaped upper tool where due to the laser heating the material is softened and thus cracks are avoided. For the technical realization of the new process of laser assisted die bending, modules equipped with numerous laser diodes and a total beam power of 2,5 kW are used. The light emitted by these modules enters a tool with a length of 15cm and is deflected towards the workpiece. By using ten of these modules with adjacent dies and by integrating those in a bending press a bending edge of sheet metals with a length of 1500mm can be realized. Such a bending press with laser assistance also needs energization with a power of practically 50kW, a respective water flow, a heat exchanger system and also a control for all functions of this system. Special measures have also been developed to avoid radiating of those tools that are not covered by a workpiece in the case of bending edges shorter than the full length of the bending tools whereas individual short circuiting of diode modules can be performed. Specific measures to ensure a safe operation without any harm to the operational person have been realized. Exploitation of the bending process has been carried out for titanium, where material thicknesses up to 3mm have been bent successfully.

  5. Review of IVR-ERVC and using flooding concept for application to high power reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Min ho; Heo, Hyo; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of)

    2016-10-15

    Accident scope will be limited in the RPV. For example, in case of Fukushima, they have difficulties for cleanup the accident and even catching the location of the melt-through corium. Therefore, IVR-ERVC is the right strategy for mitigation of the severe accident. However, in case of high power reactors, there is a Critical Heat Flux (CHF) problem in its application to high power reactor. If CHF occurred, boiling regime changes from effective nucleate boiling to ineffective film boiling, so temperature of the RPV goes up and finally the RPV fails. To solve the CHF problem, here have been a lot of works for IVR-ERVC. In the point of in-vessel heat transfer, Theofanous suggested risk oriented accident analysis methodology which is a combination of probabilistic and deterministic approach. A lot of experiments have been done using simulants of corium in various experimental apparatus. Their simulants were usually water due to simulate large Rayleigh number and natural circulation of corium. IVR-ERVC concept has been researched for a long time. For in-vessel heat transfer, simulants or real corium was used to get a heat flux distribution to the outer wall. And based on those results, ex-vessel cooling has been researched in various geometry to get cooling limit as CHF. Material flooding is suggested as improvement of ERVC in APR 1400 to secure safety margin for CHF. Regardless of Prandtl number of the flooding material, the focusing effect of heat flux was mitigated; the maximum heat flux was reduced less than half of the maximum heat flux in bare condition.

  6. Status and future prospects of laser fusion and high power laser applications

    Science.gov (United States)

    Mima, Kunioki

    2010-08-01

    In Asia, there are many institutes for the R&D of high power laser science and applications. They are 5 major institutes in Japan, 4 major institutes in China, 2 institutes in Korea, and 3 institutes in India. The recent achievements and future prospects of those institutes will be over viewed. In the laser fusion research, the FIREX-I project in Japan has been progressing. The 10kJ short pulse LFEX laser has completed and started the experiments with a single beam. About 1kJ pulse energy will be injected into a cone target. The experimental results of the FIREX experiments will be presented. As the target design for the experiments, a new target, namely, a double cone target was proposed, in which the high energy electrons are well confined and the heating efficiency is significantly improved. Together with the fusion experiments, Osaka University has carried out laboratory astrophysics experiments on photo ionizing plasmas to observe a unique X-ray spectrum from non-LTE plasmas. In 2008, Osaka university has started a new Photon research center in relation with the new program: Consortium for Photon Science and Technology: C-PhoST, in which ultra intense laser plasmas research and related education will be carried out for 10 years. At APRI, JAEA, the fundamental science on the relativistic laser plasmas and the applications of laser particle acceleration has been developed. The application of laser ion acceleration has been investigated on the beam cancer therapy since 2007. In China, The high power glass laser: Shenguan-II and a peta watt beam have been operated to work on radiation hydro dynamics at SIOFM Shanghai. The laser material and optics are developed at SIOFM and LFRC. The IAPCM and the IOP continued the studies on radiation hydrodynamics and on relativistic laser plasmas interactions. At LFRC in China, the construction of Shenguan III glass laser of 200kJ in blue has progressed and will be completed in 2012. Together with the Korean program, I will

  7. High Power Laser Diode Arrays for 2-Micron Solid State Coherent Lidars Applications

    Science.gov (United States)

    Amzajerdian, Farzin; Meadows, Byron; Kavaya, Michael J.; Singh, Upendra; Sudesh, Vikas; Baker, Nathaniel

    2003-01-01

    Laser diode arrays are critical components of any diode-pumped solid state laser systems, constraining their performance and reliability. Laser diode arrays (LDAs) are used as the pump source for energizing the solid state lasing media to generate an intense coherent laser beam with a high spatial and spectral quality. The solid state laser design and the characteristics of its lasing materials define the operating wavelength, pulse duration, and power of the laser diodes. The pump requirements for high pulse energy 2-micron solid state lasers are substantially different from those of more widely used 1-micron lasers and in many aspects more challenging [1]. Furthermore, the reliability and lifetime demanded by many coherent lidar applications, such as global wind profiling from space and long-range clear air turbulence detection from aircraft, are beyond the capability of currently available LDAs. In addition to the need for more reliable LDAs with longer lifetime, further improvement in the operational parameters of high power quasi-cw LDAs, such as electrical efficiency, brightness, and duty cycle, are also necessary for developing cost-effective 2-micron coherent lidar systems for applications that impose stringent size, heat dissipation, and power constraints. Global wind sounding from space is one of such applications, which is the main driver for this work as part of NASA s Laser Risk Reduction Program. This paper discusses the current state of the 792 nm LDA technology and the technology areas being pursued toward improving their performance. The design and development of a unique characterization facility for addressing the specific issues associated with the LDAs for pumping 2-micron coherent lidar transmitters and identifying areas of technological improvement will be described. Finally, the results of measurements to date on various standard laser diode packages, as well as custom-designed packages with potentially longer lifetime, will be reported.

  8. Coupled-Multiplier Accelerator Produces High-Power Electron Beams for Industrial Applications

    Science.gov (United States)

    Hatridge, M.; McIntyre, P.; Roberson, S.; Sattarov, A.; Thomas, E.; Meitzler, Charles

    2003-08-01

    The coupled multiplier is a new approach to efficient generation of MeV d.c. power for accelerator applications. High voltage is produced by a series of modules, each of which consists of a high-power alternator, step-up transformer, and 3-phase multiplier circuit. The alternators are connected mechanically along a rotating shaft, and connected by insulating flexible couplers. This approach differs from all previous d.c. technologies in that power is delivered to the various stages of the system mechanically, rather than through capacitive or inductive electrical coupling. For this reason the capital cost depends linearly on required voltage and power, rather than quadratically as with conventional technologies. The CM technology enables multiple electron beams to be driven within a common supply and insulating housing. MeV electron beam is extremely effective in decomposing organic contaminants in water. A 1 MeV, 100 kW industrial accelerator using the CM technology has been built and is being installed for treatment of wastewater at a petrochemical plant.

  9. Measurement of mechanical quality factors of polymers in flexural vibration for high-power ultrasonic application.

    Science.gov (United States)

    Wu, Jiang; Mizuno, Yosuke; Tabaru, Marie; Nakamura, Kentaro

    2016-07-01

    A method for measuring the mechanical quality factor (Q factor) of materials in large-amplitude flexural vibrations was devised on the basis of the original definition of the Q factor. The Q factor, the ratio of the reactive energy to the dissipated energy, was calculated from the vibration velocity distribution. The bar thickness was selected considering the effect of the thickness on the estimation error. In the experimental setup, a 1-mm-thick polymer-based bar was used as a sample and fixed on the top of a longitudinal transducer. Using transducers of different lengths, flexural waves in the frequency range of 20-90kHz were generated on the bar. The vibration strain in the experiment reached 0.06%. According to the Bernoulli-Euler model, the reactive energy and dissipated energy were estimated from the vertical velocity distribution on the bar, and the Q factors were measured as the driving frequency and strain were varied. The experimental results showed that the Q factors decrease as the driving frequencies and strains increase. At a frequency of 28.30kHz, the Q factor of poly(phenylene sulfide) (PPS) reached approximately 460 when the strain was smaller than 0.005%. PPS exhibited a much higher Q factor than the other tested polymers, which implies that it is a potentially applicable material as the elastomer for high-power ultrasonic devices. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Performance of improved magnetostrictive vibrational power generator, simple and high power output for practical applications

    Science.gov (United States)

    Ueno, Toshiyuki

    2015-05-01

    Vibration based power generation technology is utilized effectively in various fields. Author has invented novel vibrational power generation device using magnetostrictive material. The device is based on parallel beam structure consisting of a rod of iron-gallium alloy wound with coil and yoke accompanied with permanent magnet. When bending force is applied on the tip of the device, the magnetization inside the rod varies with induced stress due to the inverse magnetostrictive effect. In vibration, the time variation of the magnetization generates voltage on the wound coil. The magnetostrictive type is advantageous over conventional such using piezoelectric or moving magnet types in high efficiency and high robustness, and low electrical impedance. Here, author has established device configuration, simple, rigid, and high power output endurable for practical applications. In addition, the improved device is lower cost using less volume of Fe-Ga and permanent magnet compared to our conventional, and its assembly by soldering is easy and fast suitable for mass production. Average power of 3 mW/cm3 under resonant vibration of 212 Hz and 1.2 G was obtained in miniature prototype using Fe-Ga rod of 2 × 0.5× 7 mm3. Furthermore, the damping effect was observed, which demonstrates high energy conversion of the generator.

  11. Thermal Impact Analysis of Circulating Current in High Power Modular Online Uninterruptible Power Supplies Application

    DEFF Research Database (Denmark)

    Zhang, Chi; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2017-01-01

    In modular uninterruptible power supplies (UPSs), several DC/AC modules are required to work in parallel. This structure allows the system to be more reliable and flexible. These DC/AC modules share the same DC bus and AC critical bus. Module differences, such as filter inductor, filter capacitor...... scenarios. In this paper, plug’n’play modules and cycle control are discussed and validated through experimental results. Moreover, potential zero sequence circulating current impact on power semiconductor devices thermal performance is also analyzed in this paper.......In modular uninterruptible power supplies (UPSs), several DC/AC modules are required to work in parallel. This structure allows the system to be more reliable and flexible. These DC/AC modules share the same DC bus and AC critical bus. Module differences, such as filter inductor, filter capacitor......, control parameters, and so on, will make it possible for the potential zero sequence current to flow among the modules. This undesired type of circulating current will bring extra losses to the power semiconductor devices in the system, which should be paid special attention in high power application...

  12. High Power Electro-Optic Modulator for Space-Based Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ADVR, Inc. proposes the development of a fiber coupled, high power, electro-optically controlled, space qualified, phase modulator for the NASA Laser Interferometer...

  13. High Power Electro-Optic Modulator for Space-Based Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I effort will establish the feasibility of developing a fiber coupled, high power, electro-optically controlled, space...

  14. Application of High Power Ultrasound in Drying of Fruits and Vegetables

    Directory of Open Access Journals (Sweden)

    Werner, Z.

    2010-04-01

    Full Text Available Ultrasound is a sound frequency in the range between 18 and 100 kHz that is above hearing of the human ear. High power ultrasound means application of intensities higher than 1 W cm–2 (usually in the range between I=10–1000Wcm–2. High power and low frequency ultrasound (f = 20 to 100 kHz is considered as “power ultrasound” because its application causes cavitation and is applied in the food industry. High power ultrasound is applied for degassing of liquid food, for induction of oxidation/reduction reactions, for extraction of enzymes and proteins, for inactivation of enzymes and induction of nucleation for crystallization. Ultrasound is anticipating heat transfer; it is used for emulsifying, sterilization, extraction, degassing, filtrating, drying and induction of oxidation. Conventional hot air drying is a very energy- and cost-intensive process. Drying is a simultaneous operation of heat and mass exchange that is followed by phase changes. Application of different pretreatments, like osmotic dehydration, ultrasound and ultrasound assisted osmotic dehydration has shown different effects on fruits and vegetables. When the high intensity acoustic energy is passing through solid material, it causes several fast and successive compressions and rarefactions with speeds that depend on the frequency applied. Thus, material is exposed to a series of exchangeable squeezing and relaxations, very like continuous squeezing and releasing of the sponge. This mechanism known as "rectified diffusion" is very important in acoustic drying and migration of water. Application of ultrasound as a pretreatment has shown great influence on reducing afterward hot air drying thereby reducing total drying time. It is also shown that pretreatment before drying facilitates better mass transfer and water diffusivity than osmotic dehydration. Quality of the product after drying is better because ultrasound pretreatment is applied at room temperature thus reducing

  15. Low phase noise high power handling InGaAs photodiodes for precise timing applications

    Science.gov (United States)

    Datta, Shubhashish; Joshi, Abhay; Becker, Don

    2009-05-01

    Time is the most precisely measured physical quantity. Such precision is achieved by optically probing hyperfine atomic transitions. These high Q-factor resonances demonstrate frequency instability of ~10-18 over 1 s observation time. Conversion of such a stable optical clock signal to an electrical clock through photodetection introduces additional phase noise, thereby resulting in a significant degradation in the frequency stability. This excess phase noise is primarily caused by the conversion of optical intensity noise into electrical phase noise by the phase non-linearity of the photodetector, characterized by its power-to-phase conversion factor. It is necessary to minimize this phase nonlinearity in order to develop the next generation of ultra-high precision electronic clocks. Reduction in excess phase noise must be achieved while ensuring a large output RF signal generated by the photodetector. The phase linearity in traditional system designs that employ a photoreceiver, namely a photodiode followed by a microwave amplifier, is limited by the phase non-linearity of the amplifier. Utilizing high-power handling photodiodes eliminates the need of microwave amplifiers. In this work, we present InGaAs p-i-n photodiodes that display a power-to-phase conversion factor RF output amplitude of 2 V. In comparison, the photodiode coupled to a transimpedance amplifier demonstrates >44 rad/W at a peak-to-peak RF output amplitude of 0.5 V. These results are supported by impulse response measurements at 1550 nm wavelength at 1 GHz repetition rate. These photodiodes are suitable of applications such as optical clock distribution networks, photonic analog-to-digital converters, and phased array radars.

  16. A compact high power Er:Yb:glass eyesafe laser for infrared remote sensing applications

    Science.gov (United States)

    Vitiello, Marco; Pizzarulli, Andrea; Ruffini, Andrea

    2010-10-01

    The key features and performances of a compact, lightweight, high power Er3+:Yb3+ glass laser transmitter are reported on. The theory employed to get an optimal design of the device is also described. In free running regime high energies of about 15mJ in 3ms long pulses were obtained, with an optical efficiency close to 85%. When q-switched by a Co: MALO crystal of carefully selected initial transmittivity, a high peak power in excess of 500 kW was obtained in about 9ns pulse duration, with an optical efficiency of 60%. The laser was successfully run with no significant power losses at repetition rates up to 5Hz due to a carefully designed heat sink which allowed an efficient conduction cooling of both the diode bars and the phosphate glass. The transmitter emits at a wavelength of 1535nm in the so-called "eyesafe" region of the light spectrum thus being highly attractive for any application involving the risk of human injury as is typically the case in remote sensing activities. Moreover, the spectral band around 1,5mm corresponds to a peak in the athmospheric transmittance thus being more effective in adverse weather conditions with respect to other wavelengths. Actually, the device has been successfully integrated into a rangefinder system allowing a reliable and precise detection of small targets at distances up to 20Km. Moreover, the transmitter capabilities were used into a state of the art infrared laser illuminator for night vision allowing even the recognition of a human being at distances in excess of 5Km.

  17. First Results with a Fast Phase and Amplitude Modulator for High Power RF Application

    CERN Document Server

    Frischholz, Hans; Valuch, D; Weil, C

    2004-01-01

    In a high energy and high power superconducting proton linac, it is more economical to drive several cavities with a single high power transmitter rather than to use one transmitter per cavity. However, this option has the disadvantage of not permitting individual control for each cavity, which potentially leads to instabilities. Provided that it can be built at a reasonable cost, a fast phase and amplitude modulator inserted into each cavity feeder line can provide the necessary control capability. A prototype of such a device has been built, based on two fast and compact high power RF phase-shifters, magnetically biased by external coils. The design is described, together with the results obtained at high and low power levels.

  18. Low-Cost and High-Gain SIW Circularly Polarized Circular-Horn-Loaded Antenna for Broadband Millimeter-Wave Applications

    Directory of Open Access Journals (Sweden)

    Ming Du

    2017-09-01

    Full Text Available A wideband, low-cost and high-gain circularly polarized (CP circular-horn-loaded antenna based on substrate integrated waveguide (SIW technology operating at Ka band is presented. The proposed antenna, which is built on a single-layer substrate, consists of five parts: a short-ended SIW, a centro-symmetric wide slot, an L-shaped probe, a circular horn and a transition from SIW to air-filled rectangular waveguide for measurement. The slot is etched on the upper ground of the SIW, while the L-shaped probe for generating CP wave is printed inside the slot and connected to the SIW. A circular horn is also loaded on the surface of the SIW slot for high gain. Then, the proposed antenna with a dimension of 45×45×24.16 mm3 was fabricated and measured. The measured results show that the antenna has a wide impedance matching bandwidth of 28.6% from 30 to 40 GHz for |S11| ≤10 dB and a wide axial ratio (AR bandwidth of 22.8% from 31.5 to 39.6 GHz for AR ≤ 3 dB. The measured maximum gain is 15.6 dBi at 36 GHz with slight fluctuations over the 30–40-GHz frequency range. This kind of antenna merits low cost and easy integration with common differential circuits at the same time.

  19. 1 GHz GaAs Buck Converter for High Power Amplifier Modulation Applications

    NARCIS (Netherlands)

    Busking, E.B.; Hek, A.P. de; Vliet, F.E. van

    2012-01-01

    A fully integrated 1 GHz buck converter output stage, including on-chip inductor and DC output filtering has been realized, in a standard high-voltage breakdown GaAs MMIC technology. This is a significant step forward in designing highspeed power control of supply-modulated HPAs (high power

  20. A high-power ultrasonic microreactor and its application in gas-liquid mass transfer intensification.

    Science.gov (United States)

    Dong, Zhengya; Yao, Chaoqun; Zhang, Xiaoli; Xu, Jie; Chen, Guangwen; Zhao, Yuchao; Yuan, Quan

    2015-02-21

    The combination of ultrasound and microreactor is an emerging and promising area, but the report of designing high-power ultrasonic microreactor (USMR) is still limited. This work presents a robust, high-power and highly efficient USMR by directly coupling a microreactor plate with a Langevin-type transducer. The USMR is designed as a longitudinal half wavelength resonator, for which the antinode plane of the highest sound intensity is located at the microreactor. According to one dimension design theory, numerical simulation and impedance analysis, a USMR with a maximum power of 100 W and a resonance frequency of 20 kHz was built. The strong and uniform sound field in the USMR was then applied to intensify gas-liquid mass transfer of slug flow in a microfluidic channel. Non-inertial cavitation with multiple surface wave oscillation was excited on the slug bubbles, enhancing the overall mass transfer coefficient by 3.3-5.7 times.

  1. Design and experiment of a cross-shaped mode converter for high-power microwave applications

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Shengren, E-mail: 785751053@qq.com; Yuan, Chengwei; Zhong, Huihuang; Fan, Yuwei [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2013-12-15

    A compact mode converter, which is capable of converting a TM{sub 01} mode into a circularly polarized TE{sub 11} mode, was developed and experimentally studied with high-power microwaves. The converter, consisting of two turnstile junctions, is very short along the wave propagation direction, and therefore is suitable for designing compact and axially aligned high-power microwave radiation systems. In this paper, the principle of a converter working at 1.75 GHz is demonstrated, as well as the experimental results. The experimental and simulation results are in good agreement. At the center frequency, the conversion efficiency is more than 95%, the measured axial ratio is about 0.4 dB, and the power-handing capacity is excess of 1.9 GW.

  2. Design and experiment of a cross-shaped mode converter for high-power microwave applications

    Science.gov (United States)

    Peng, Shengren; Yuan, Chengwei; Zhong, Huihuang; Fan, Yuwei

    2013-12-01

    A compact mode converter, which is capable of converting a TM01 mode into a circularly polarized TE11 mode, was developed and experimentally studied with high-power microwaves. The converter, consisting of two turnstile junctions, is very short along the wave propagation direction, and therefore is suitable for designing compact and axially aligned high-power microwave radiation systems. In this paper, the principle of a converter working at 1.75 GHz is demonstrated, as well as the experimental results. The experimental and simulation results are in good agreement. At the center frequency, the conversion efficiency is more than 95%, the measured axial ratio is about 0.4 dB, and the power-handing capacity is excess of 1.9 GW.

  3. Overview on the high power excimer laser technology

    Science.gov (United States)

    Liu, Jingru

    2013-05-01

    High power excimer laser has essential applications in the fields of high energy density physics, inertial fusion energy and industry owing to its advantages such as short wavelength, high gain, wide bandwidth, energy scalable and repetition operating ability. This overview is aimed at an introduction and evaluation of enormous endeavor of the international high power excimer laser community in the last 30 years. The main technologies of high power excimer laser are reviewed, which include the pumping source technology, angular multiplexing and pulse compressing, beam-smoothing and homogenous irradiation, high efficiency and repetitive operation et al. A high power XeCl laser system developed in NINT of China is described in detail.

  4. Design and High Power Measurements of a 3 GHz Rotary Joint for Medical Applications

    CERN Document Server

    Degiovanni, Alberto; Garlasche, Marco; Giner-Navarro, Jorge; Magagnin, Paolo; Mcmonagle, Gerard; Syratchev, Igor; Wuensch, Walter

    2016-01-01

    The TUrning LInac for Protontherapy (TULIP) project requires the transport of RF power from modulator/klystron systems at rest on the floor to the linac structures mounted on a rotating gantry, via a waveguide system that can operate over a range of angles of rotation. A waveguide rotary joint capable of transporting RF power at 3 GHz and up to 20 MW has been designed and built in collaboration between TERA Foundation, CERN Beams and CERN Engineering Departments. A high-power test of the prototype has been performed at the CLIC Test Facility (CTF3), at CERN. The design and the results of the tests are reported in this article.

  5. Research on the honeycomb restrain layer application to the high power microwave dielectric window

    Science.gov (United States)

    Zhang, Qingyuan; Shao, Hao; Huang, Wenhua; Guo, Letian

    2018-01-01

    Dielectric window breakdown is an important problem of high power microwave radiation. A honeycomb layer can suppress the multipactor in two directions to restrain dielectric window breakdown. This paper studies the effect of the honeycomb restrain layer on improving the dielectric window power capability. It also studies the multipactor suppression mechanism by using the electromagnetic particle-in-cell software, gives the design method, and accomplishes the test experiment. The experimental results indicated that the honeycomb restrain layer can effectively improve the power capability twice.

  6. A Single-Stage High-Power-Factor Light-Emitting Diode (LED) Driver with Coupled Inductors for Streetlight Applications

    OpenAIRE

    Chun-An Cheng; Chien-Hsuan Chang; Hung-Liang Cheng; Ching-Hsien Tseng; Tsung-Yuan Chung

    2017-01-01

    This paper presents and implements a single-stage high-power-factor light-emitting diode (LED) driver with coupled inductors, suitable for streetlight applications. The presented LED driver integrates an interleaved buck-boost power factor correction (PFC) converter with coupled inductors and a half-bridge-type series-resonant converter cascaded with a full-bridge rectifier into a single-stage power conversion circuit. Coupled inductors inside the interleaved buck-boost PFC converter sub-circ...

  7. A Single-Stage High-Power-Factor Light-Emitting Diode (LED Driver with Coupled Inductors for Streetlight Applications

    Directory of Open Access Journals (Sweden)

    Chun-An Cheng

    2017-02-01

    Full Text Available This paper presents and implements a single-stage high-power-factor light-emitting diode (LED driver with coupled inductors, suitable for streetlight applications. The presented LED driver integrates an interleaved buck-boost power factor correction (PFC converter with coupled inductors and a half-bridge-type series-resonant converter cascaded with a full-bridge rectifier into a single-stage power conversion circuit. Coupled inductors inside the interleaved buck-boost PFC converter sub-circuit are designed to operate in discontinuous conduction mode (DCM for achieving input-current shaping, and the half-bridge-type series resonant converter cascaded with a full-bridge rectifier is designed for obtaining zero-voltage switching (ZVS on two power switches to reduce their switching losses. Analysis of operational modes and design equations for the presented LED driver are described and included. In addition, the presented driver features a high power factor, low total harmonic distortion (THD of input current, and soft switching. Finally, a prototype driver is developed and implemented to supply a 165-W-rated LED streetlight module with utility-line input voltages ranging from 210 to 230 V. Experimental results demonstrate that high power factor (>0.99, low utility-line current THD (<7%, low-output voltage ripples (<1%, low-output current ripples (<10%, and high circuit efficiency (>90% are obtained in the presented single-stage driver for LED streetlight applications.

  8. High-power fiber-coupled 100W visible spectrum diode lasers for display applications

    Science.gov (United States)

    Unger, Andreas; Küster, Matthias; Köhler, Bernd; Biesenbach, Jens

    2013-02-01

    Diode lasers in the blue and red spectral range are the most promising light sources for upcoming high-brightness digital projectors in cinemas and large venue displays. They combine improved efficiency, longer lifetime and a greatly improved color space compared to traditional xenon light sources. In this paper we report on high-power visible diode laser sources to serve the demands of this emerging market. A unique electro-optical platform enables scalable fiber coupled sources at 638 nm with an output power of up to 100 W from a 400 μm NA0.22 fiber. For the blue diode laser we demonstrate scalable sources from 5 W to 100 W from a 400 μm NA0.22 fiber.

  9. Forthcoming Gallium Nitride Based Power Devices in Prompting the Development of High Power Applications

    Science.gov (United States)

    Quah, H. J.; Cheong, K. Y.; Hassan, Z.

    Recent advances in silicon technology have pushed the silicon properties to its theoretical limits. Therefore, wide band gap semiconductors, such as silicon carbide (SiC) and gallium nitride (GaN) have been considered as a replacement for silicon. The discovery of these wide band gap semiconductors have given the new generation power devices a magnificent prospect of surviving under high temperature and hostile environments. The primary focuses of this review are the properties of GaN, the alternative substrates that can be used to deposit GaN and the substitution of SiO2 gate dielectric with high dielectric constant (k) film. The future perspectives of AlGaN/GaN heterostructures are also discussed, providing that these structures are able to further enhance the performance of high power devices.

  10. Development of High Power Amplifiers for Space and Ground-based Applications

    DEFF Research Database (Denmark)

    Hernández, Carlos Cilla

    -based amplifiers. They are efficient and provide very high power levels operating at low duty cycles. But they have a questionable longterm reliability, large footprints and they are not suitable for modern equipment with a decentralized transmitter, like a phase array system. Solid State Power Amplifier...... technology is the alternative to the tube-based amplifiers. Recently, there has been a renewed interest in this research field thanks, to a large extent, to the development of GaN semiconductor technology, that is already having an important impact on the wireless and radar market. The scope of this Ph...... Circuit GaN technology is discussed. The design will be used as a baseline for future developments of the next generation of the Sentinel satellite remote sensing radar T/R modules. The twostage design features a 6730 X 3750 µm2 compact footprint. The overlapping between simulated intrinsic drain current...

  11. Design of a slot-coupled radial line helical array antenna for high power microwave applications

    Directory of Open Access Journals (Sweden)

    Longzhou Yu

    2017-09-01

    Full Text Available An eight-ring radial helical array antenna based on a novel slot-coupled structure is designed and simulated. The novel coupling structure has the advantages of high power-handling capacity and excellent coupling ability. The simulation results of the array antenna agree well with theoretical calculations, and the aperture efficiency is about 78.1% when the beam is in the normal direction. The power-handling capacity is about 100 MW on vacuum condition. The simulation results also show that the gain is 30.7 dB and the main lobe’s axial ratio is 0.25 dB. Furthermore, the structure of the antenna is compact, and it may be applied to larger circular helical arrays to realize higher gain and higher power-handling capacity.

  12. A Novel WPT System Based on Dual Transmitters and Dual Receivers for High Power Applications: Analysis, Design and Implementation

    Directory of Open Access Journals (Sweden)

    Yong Li

    2017-02-01

    Full Text Available Traditional Wireless Power Transfer (WPT systems only have one energy transmission path, which can hardly meet the power demand for high power applications, e.g., railway applications (electric trains and trams, etc. due to the capacity constraints of power electronic devices. A novel WPT system based on dual transmitters and dual receivers is proposed in this paper to upgrade the power capacity of the WPT system. The reliability and availability of the proposed WPT system can be dramatically improved due to the four energy transmission paths. A three-dimensional finite element analysis (FEA tool ANSYS MAXWELL (ANSYS, Canonsburg, PA, USA is adopted to investigate the proposed magnetic coupling structure. Besides, the effects of the crossing coupling mutual inductances among the transmitters and receivers are analyzed. It shows that the same-side cross couplings will decrease the efficiency and transmitted power. Decoupling transformers are employed to mitigate the effects of the same-side cross couplings. Meanwhile, the output voltage in the secondary side can be regulated at its designed value with a fast response performance, and the system can continue work even with a faulty inverter. Finally, a scale-down experimental setup is provided to verify the proposed approach. The experimental results indicate that the proposed method could improve the transmitted power capacity, overall efficiency and reliability, simultaneously. The proposed WPT structure is a potential alternative for high power applications.

  13. High Power Electronics

    Science.gov (United States)

    Pendharker, Sameer

    High Power Electronics Future Trends: New process, circuit and packaging technologies over the last 5 years have led to significant innovation and technological developments in high power electronics. In this topic, the trends and performance improvements achieved in the industry will be discussed with focus on gallium-nitride (GaN) and silicon carbide (SiC). Both GaN and SiC technologies have been around for many years but have seen limited adoption and proliferation in high power systems. With the improved transistor performance, power conversion efficiencies and densities previously unrealizable are now available leading to new applications and new system. Trends in these technologies will also be reviewed and remaining challenges to overcome before true mass market adoption can be expected.

  14. Towards swift ion bunch acceleration by high-power laser pulses at the Centre for Advanced Laser Applications (CALA)

    Science.gov (United States)

    Lindner, F. H.; Haffa, D.; Bin, J. H.; Englbrecht, F.; Gao, Y.; Gebhard, J.; Hartmann, J.; Hilz, P.; Kreuzer, C.; Lehrack, S.; Ostermayr, T. M.; Rösch, T. F.; Speicher, M.; Würl, M.; Parodi, K.; Schreiber, J.; Thirolf, P. G.

    2017-07-01

    Laser-driven acceleration of ions has inspired novel applications, that can benefit from ion bunch properties different from conventionally (non-laser based) accelerated particle beams. Those differences range from extremely short bunch durations, broad energy spectra, large divergence angles and small source sizes to ultra-high ion bunch densities. So far, the main focus of research has been concentrating on the physics of the interaction of intense laser pulses with plasmas and the related mechanisms of ion acceleration. Now, the new Centre for Advanced Laser Applications (CALA) near Munich aims at pushing these ion bunches towards applications, including radiation therapy of tumors and the development of heavy ion bunches with solid-state-like density. These are needed for novel reaction mechanisms ('fission-fusion') to study the origin of heavy elements in the universe and to prepare for related studies at the upcoming EU-funded high-power laser facility ELI - Nuclear Physics in Bucharest.

  15. High power laser-driven ceramic phosphor plate for outstanding efficient white light conversion in application of automotive lighting.

    Science.gov (United States)

    Song, Young Hyun; Ji, Eun Kyung; Jeong, Byung Woo; Jung, Mong Kwon; Kim, Eun Young; Yoon, Dae Ho

    2016-08-09

    We report on Y3Al5O12: Ce(3+) ceramic phosphor plate (CPP) using nano phosphor for high power laser diode (LD) application for white light in automotive lighting. The prepared CPP shows improved luminous properties as a function of Ce(3+) concentration. The luminous properties of the Y3Al5O12: Ce(3+) CPP nano phosphor are improved when compared to the Y3Al5O12: Ce(3+) CPP with bulk phosphor, and hence, the luminous emittance, luminous flux, and conversion efficiency are improved. The Y3Al5O12: Ce(3+) CPP with an optimal Ce(3+) content of 0.5 mol % shows 2733 lm/mm(2) value under high power blue radiant flux density of 19.1 W/mm(2). The results indicate that Y3Al5O12: Ce(3+) CPP using nano phosphor can serve as a potential material for solid-state laser lighting in automotive applications.

  16. Innovative application of ionic liquid to separate Al and cathode materials from spent high-power lithium-ion batteries.

    Science.gov (United States)

    Zeng, Xianlai; Li, Jinhui

    2014-04-30

    Because of the increasing number of electric vehicles, there is an urgent need for effective recycling technologies to recapture the significant amount of valuable metals contained in spent lithium-ion batteries (LiBs). Previous studies have indicated, however, that Al and cathode materials were quite difficult to separate due to the strong binding force supplied by the polyvinylidene fluoride (PVDF), which was employed to bind cathode materials and Al foil. This research devoted to seek a new method of melting the PVDF binder with heated ionic liquid (IL) to separate Al foil and cathode materials from the spent high-power LiBs. Theoretical analysis based on Fourier's law was adopted to determine the heat transfer mechanism of cathode material and to examine the relationship between heating temperature and retention time. All the experimental and theoretic results show that peel-off rate of cathode materials from Al foil could reach 99% when major process parameters were controlled at 180°C heating temperature, 300 rpm agitator rotation, and 25 min retention time. The results further imply that the application of IL for recycling Al foil and cathode materials from spent high-power LiBs is highly efficient, regardless of the application source of the LiBs or the types of cathode material. This study endeavors to make a contribution to an environmentally sound and economically viable solution to the challenge of spent LiB recycling. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. High Power High Thrust Ion Thruster (HPHTion): 50 CM Ion Thruster for Near-Earth Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advances in high power, photovoltaic technology has enabled the possibility of reasonably sized, high specific power, high power, solar arrays. At high specific...

  18. High Power High Thrust Ion Thruster (HPHTion): 50 CM Ion Thruster for Near-Earth Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advances in high power, photovoltaic technology has enabled the possibility of reasonably sized, high specific power, high power, solar arrays. New thin film solar...

  19. Towards High Power Density Metal Supported Solid Oxide Fuel Cell for Mobile Applications

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Persson, Åsa Helen; Muhl, Thuy

    2017-01-01

    For use of metal supported SOFC in mobile applications it is important to reduce the thermal mass to enable fast start up, increase stack power density in terms of weight and volume and reduce costs. In the present study, we report on the effect of reducing the support layer thickness of 313 μm...

  20. Optical systems for high-power laser applications: principles and design aspects

    NARCIS (Netherlands)

    Beckmann, L.H.J.F.; Ehrlichmann, D.

    1995-01-01

    Starting from the optical properties of laser beams, the requirements of optical systems for manipulating laser radiation in industrial applications are derived. The relevant parameters, relations to the diffraction limit and the state-of-the-art design techniques are discussed. The three important

  1. High Power Combiner/Divider with Coupled Lines for Broadband Applications

    Science.gov (United States)

    2017-03-20

    are required for emerging applications in Electronic Warfare (EW), multi-band radar, and multi- function RF. The Wilkinson divider is one of the most...introduce signal filtering or dual band operation [8]. The use of coupled lines gives flexibility. However, the added complexity may lead to greater...of the original Gysel structure (with its low loss, due to low impedance, lines) while introducing the minimum number of coupled lines. This

  2. Fundamental Studies and Development of III-N Visible LEDs for High-Power Solid-State Lighting Applications

    Energy Technology Data Exchange (ETDEWEB)

    Dupuis, Russell

    2012-02-29

    The goal of this program is to understand in a fundamental way the impact of strain, defects, polarization, and Stokes loss in relation to unique device structures upon the internal quantum efficiency (IQE) and efficiency droop (ED) of III-nitride (III-N) light-emitting diodes (LEDs) and to employ this understanding in the design and growth of high-efficiency LEDs capable of highly-reliable, high-current, high-power operation. This knowledge will be the basis for our advanced device epitaxial designs that lead to improved device performance. The primary approach we will employ is to exploit new scientific and engineering knowledge generated through the application of a set of unique advanced growth and characterization tools to develop new concepts in strain-, polarization-, and carrier dynamics-engineered and low-defect materials and device designs having reduced dislocations and improved carrier collection followed by efficient photon generation. We studied the effects of crystalline defect, polarizations, hole transport, electron-spillover, electron blocking layer, underlying layer below the multiplequantum- well active region, and developed high-efficiency and efficiency-droop-mitigated blue LEDs with a new LED epitaxial structures. We believe new LEDs developed in this program will make a breakthrough in the development of high-efficiency high-power visible III-N LEDs from violet to green spectral region.

  3. Next generation 9xx/10xx nm high power laser diode bars for multi-kilowatt industrial applications

    Science.gov (United States)

    Commin, Paul; Todt, René; Krejci, Martin; Bättig, Rainer; Brunner, Reinhard; Lichtenstein, Norbert

    2013-02-01

    We report on the development of high power, 9xx-10xx nm laser diode bars for use in direct diode systems and for solidstate and fibre laser pumping with applications in industrial markets. For 1 cm wide bars on micro channel cooler (MCC) we have achieved a reliable output power of 250 W across the 900 nm - 1060 nm range. At this output power level we have achieved power conversion efficiencies of 65-66 % and 90 % power content slow axis beam divergence of ~6.5°. Results of a 6400 h life test show an average power degradation of 0.6 % per 1000 h at this operating power level. We will also show results of high power bars assembled on the new OCLARO conductive cooler, the BLM. This new cooler has a small footprint of 12.6 mm × 24.8 mm and is designed for lateral or vertical stacking of diodes in multi kilowatt systems but with the benefits associated with a conductive cooler. The thermal properties are shown to be the same as for a standard CS mount. 1 cm wide high fill factor bars and 0.5 cm wide low fill factor half bars assembled on the BLM operate at 63-64 % power conversion efficiency (PCE) with output powers of up to 250 W and 150 W, respectively.

  4. A Family of L-band SRF Cavities for High Power Proton Driver Applications

    Energy Technology Data Exchange (ETDEWEB)

    Robert Rimmer, Frank Marhauser

    2009-05-01

    Recent global interest in high duty factor or CW superconducting linacs with high average beam power highlights the need for robust and reliable SRF structures capable of delivering high average RF power to the beam with moderate HOM damping, low interception of halo and good efficiency. Potential applications include proton or H- drivers for spallation neutron sources, neutrino physics, waste transmutation, subcritical reactors, and high-intensity high-energy physics experiments. We describe a family of SRF cavities with a range of Betas capable of transporting beam currents in excess of 10 mA CW with large irises for minimal interception of halo and HOM and power couplers capable of supporting high average power operation. Goals include an efficient cell shape, high packing factor for efficient real-estate gradient and strong HOM damping to ensure stable beam operation,

  5. One-step synthesis of highly reduced graphene hydrogels for high power supercapacitor applications

    Science.gov (United States)

    Banda, Harish; Aradilla, David; Benayad, Anass; Chenavier, Yves; Daffos, Barbara; Dubois, Lionel; Duclairoir, Florence

    2017-08-01

    Graphene hydrogels with high electrical conductivity were prepared by a one-step process using hydrazine hydrate as gel assembly agent (GH-HD). Conventional two-step process of gel formation and further reduction to prepare highly conducting gels was replaced by a single step involving equivalent amount of hydrazine. Optimized graphene oxide concentration was established to facilitate such monolith formation. Extensive characterization and control studies enabled understanding of the material properties and gel formation mechanism. The synthesized gel shows a high electrical conductivity of 1141 S/m. The supercapacitor based on GH-HD delivers a high specific capacitance of 190 F/g at a current density of 0.5 A/g and 123 F/g at very high current density of 100 A/g. Furthermore, excellent power capability and cyclic stability were also observed. 3D macroporous morphology of GH-HD makes it ideal for high rate supercapacitor applications.

  6. Bulk damage and absorption in fused silica due to high-power laser applications

    Science.gov (United States)

    Nürnberg, F.; Kühn, B.; Langner, A.; Altwein, M.; Schötz, G.; Takke, R.; Thomas, S.; Vydra, J.

    2015-11-01

    Laser fusion projects are heading for IR optics with high broadband transmission, high shock and temperature resistance, long laser durability, and best purity. For this application, fused silica is an excellent choice. The energy density threshold on IR laser optics is mainly influenced by the purity and homogeneity of the fused silica. The absorption behavior regarding the hydroxyl content was studied for various synthetic fused silica grades. The main absorption influenced by OH vibrational excitation leads to different IR attenuations for OH-rich and low-OH fused silica. Industrial laser systems aim for the maximum energy extraction possible. Heraeus Quarzglas developed an Yb-doped fused silica fiber to support this growing market. But the performance of laser welding and cutting systems is fundamentally limited by beam quality and stability of focus. Since absorption in the optical components of optical systems has a detrimental effect on the laser focus shift, the beam energy loss and the resulting heating has to be minimized both in the bulk materials and at the coated surfaces. In collaboration with a laser research institute, an optical finisher and end users, photo thermal absorption measurements on coated samples of different fused silica grades were performed to investigate the influence of basic material properties on the absorption level. High purity, synthetic fused silica is as well the material of choice for optical components designed for DUV applications (wavelength range 160 nm - 260 nm). For higher light intensities, e.g. provided by Excimer lasers, UV photons may generate defect centers that effect the optical properties during usage, resulting in an aging of the optical components (UV radiation damage). Powerful Excimer lasers require optical materials that can withstand photon energy close to the band gap and the high intensity of the short pulse length. The UV transmission loss is restricted to the DUV wavelength range below 300 nm and

  7. Pinched propagation of high-power, pulsed electron beams for welding and materials processing applications

    Science.gov (United States)

    Fernsler, Richard F.; Hubbard, Richard F.; Lampe, Martin

    1994-01-01

    Electron beams are used commercially as intense heating sources for welding and related materials processing applications. The beams used for welding operate continuously with energy up to 200 keV and current approximately 1 A. Because these beams are severely degraded by propagation in air over any substantial range, most present-day electron-beam welders require vacuum pumping and precision focusing, which has severely restricted utilization of the technology. Over the past few decades, a different class of electron-beam generators has been developed that produces pulsed beams with energies of several MeV, currents of 1 kA or more, radii as small as 1 mm, pulse lengths of tens of ns, and pulse repetition rates up to several kHz. We show here that beams of this type can propagate in ambient air, in a tightly pinched mode and with acceptable stability, over distances of a few tens of cm. We determine the constraints on the choice of beam parameters, due mainly to the effects of gas scattering and the resistive instability. We show that stability can be enhanced, and the acceptable parameter range extended considerably, by using a narrow conducting pipe filled with air or another gas to guide the beam to the workpiece.

  8. MW-assisted synthesis of LiFePO{sub 4} for high power applications

    Energy Technology Data Exchange (ETDEWEB)

    Beninati, Sabina; Damen, Libero; Mastragostino, Marina [University of Bologna, Department of Metal Science, Electrochemistry and Chemical Techniques, Via San Donato 15, 40127 Bologna (Italy)

    2008-06-01

    LiFePO{sub 4}/C was prepared by solid-state reaction from Li{sub 3}PO{sub 4}, Fe{sub 3}(PO{sub 4}){sub 2}.8H{sub 2}O, carbon and glucose in a few minutes in a scientific MW (microwave) oven with temperature and power control. The material was characterized by X-ray diffraction, scanning electron microscopy and by TGA analysis to evaluate carbon content. The electrochemical characterization as positive electrode in EC (ethylene carbonate)-DMC (dimethylcarbonate) 1 M LiPF{sub 6} was performed by galvanostatic charge-discharge cycles at C/10 to evaluate specific capacity and by sequences of 10 s discharge-charge pulses, at different high C-rates (5-45C) to evaluate pulse-specific power in simulate operative conditions for full-HEV application. The maximum pulse-specific power and, particularly, pulse efficiency values are quite high and make MW synthesis a very promising route for mass production of LiFePO{sub 4}/C for full-HEV batteries at low energy costs. (author)

  9. Efficient, High-Power Mid-Infrared Laser for National Securityand Scientific Applications

    Energy Technology Data Exchange (ETDEWEB)

    Kiani, Leily S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-11-02

    The LLNL fiber laser group developed a unique short-wave-infrared, high-pulse energy, highaverage- power fiber based laser. This unique laser source has been used in combination with a nonlinear frequency converter to generate wavelengths, useful for remote sensing and other applications in the mid-wave infrared (MWIR). Sources with high average power and high efficiency in this MWIR wavelength region are not yet available with the size, weight, and power requirements or energy efficiency necessary for future deployment. The LLNL developed Fiber Laser Pulsed Source (FiLPS) design was adapted to Erbium doped silica fibers for 1.55 μm pumping of Cadmium Silicon Phosphide (CSP). We have demonstrated, for the first time optical parametric amplification of 2.4 μm light via difference frequency generation using CSP with an Erbium doped fiber source. In addition, for efficiency comparison purposes, we also demonstrated direct optical parametric generation (OPG) as well as optical parametric oscillation (OPO).

  10. High-Temperature High-Power Packaging Techniques for HEV Traction Applications

    Energy Technology Data Exchange (ETDEWEB)

    Barlow, F.D.; Elshabini, A.

    2006-11-30

    cost reduction of these systems could be achieved is through the use of a single coolant loop for both the power electronics as well as the internal combustion engine (ICE) [2]. This change would reduce the complexity of the cooling system which currently relies on two loops to a single loop [3]. However, the current nominal coolant temperature entering these inverters is 65 C [3], whereas a normal ICE coolant temperature would be much higher at approximately 100 C. This change in coolant temperature significantly increases the junction temperatures of the devices and creates a number of challenges for both device fabrication and the assembly of these devices into inverters and converters for HEV and PHEV applications. With this change in mind, significant progress has been made on the use of SiC devices for inverters that can withstand much higher junction temperatures than traditional Si based inverters [4,5,6]. However, a key problem which the single coolant loop and high temperature devices is the effective packaging of these devices and related components into a high temperature inverter. The elevated junction temperatures that exist in these modules are not compatible with reliable inverters based on existing packaging technology. This report seeks to provide a literature survey of high temperature packaging and to highlight the issues related to the implementation of high temperature power electronic modules for HEV and PHEV applications. For purposes of discussion, it will be assumed in this report that 200 C is the targeted maximum junction temperature.

  11. High-Temperature High-Power Packaging Techniques for HEV Traction Applications

    Energy Technology Data Exchange (ETDEWEB)

    Elshabini, Aicha [University of Idaho; Barlow, Fred D. [University of Idaho

    2006-11-01

    A key issue associated with the wider adoption of hybrid-electric vehicles (HEV) and plug in hybrid-electric vehicles (PHEV) is the implementation of the power electronic systems that are required in these products. One of the primary industry goals is the reduction in the price of these vehicles relative to the cost of traditional gasoline powered vehicles. Today these systems, such as the Prius, utilize one coolant loop for the engine at approximately 100 C coolant temperatures, and a second coolant loop for the inverter at 65 C. One way in which significant cost reduction of these systems could be achieved is through the use of a single coolant loop for both the power electronics as well as the internal combustion engine (ICE). This change in coolant temperature significantly increases the junction temperatures of the devices and creates a number of challenges for both device fabrication and the assembly of these devices into inverters and converters for HEV and PHEV applications. Traditional power modules and the state-of-the-art inverters in the current HEV products, are based on chip and wire assembly and direct bond copper (DBC) on ceramic substrates. While a shift to silicon carbide (SiC) devices from silicon (Si) devices would allow the higher operating temperatures required for a single coolant loop, it also creates a number of challenges for the assembly of these devices into power inverters. While this traditional packaging technology can be extended to higher temperatures, the key issues are the substrate material and conductor stability, die bonding material, wire bonds, and bond metallurgy reliability as well as encapsulation materials that are stable at high operating temperatures. The larger temperature differential during power cycling, which would be created by higher coolant temperatures, places tremendous stress on traditional aluminum wire bonds that are used to interconnect power devices. Selection of the bond metallurgy and wire bond

  12. The development of kilohertz planar laser diagnostics for applications in high power turbulent flames

    Science.gov (United States)

    Slabaugh, Carson Daniel

    In modern gas-turbine combustors, flame stabilization is achieved by inducing exhaust gas circulation within the flame zone through swirl-induced vortex breakdown. Swirling flows exhibit strong shear regions resulting in high turbulence and effective mixing. In combustion, these flows are characterized by complex unsteady interactions between turbulent flow structures and chemical reactions. Developments in high-resolution, quantitative, experimental measurement techniques must continue to improve fundamental understanding and support modeling efforts. This work describes the development of a gas turbine combustion experiment to support the application of advanced optical measurement techniques in flames operating at realistic engine conditions. Facility requirements are addressed, including instrumentation and control needs for remote operation when working with high energy flows. The methodology employed in the design of the optically-accessible combustion chamber is elucidated, including window considerations and thermal management of the experimental hardware under extremely high heat loads. Experimental uncertainties are also quantified. The stable operation of the experiment is validated using multiple techniques and the boundary conditions are verified. The successful prediction of operating conditions by the design analysis is documented and preliminary data is shown to demonstrate the capability of the experiment to produce high-fidelity datasets for advanced combustion research. Building on this experimental infrastructure, simultaneous measurements of velocity and scalar fields were performed in turbulent nonpremixed flames at gas turbine engine operating conditions using 5 kHz Particle-Image Velocimetry (PIV) and OH Planar Laser Induced Fluorescence (OH-PLIF). The experimental systems and the challenges associated with acquiring useful data at high pressures and high thermal powers are discussed. The quality of the particle scattering images used in the

  13. Systematic Approach for Design of Broadband, High Efficiency, High Power RF Amplifiers

    National Research Council Canada - National Science Library

    Mohadeskasaei, Seyed Alireza; An, Jianwei; Chen, Yueyun; Li, Zhi; Abdullahi, Sani Umar; Sun, Tie

    2017-01-01

    ...‐AB RF amplifiers with high gain flatness. It is usually difficult to simultaneously achieve a high gain flatness and high efficiency in a broadband RF power amplifier, especially in a high power design...

  14. The Development of the Electrically Controlled High Power RF Switch and Its Application to Active RF Pulse Compression Systems

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jiquan [Stanford Univ., CA (United States)

    2008-12-01

    In the past decades, there has been increasing interest in pulsed high power RF sources for building high-gradient high-energy particle accelerators. Passive RF pulse compression systems have been used in many applications to match the available RF sources to the loads requiring higher RF power but a shorter pulse. Theoretically, an active RF pulse compression system has the advantage of higher efficiency and compactness over the passive system. However, the key component for such a system an element capable of switching hundreds of megawatts of RF power in a short time compared to the compressed pulse width is still an open problem. In this dissertation, we present a switch module composed of an active window based on the bulk effects in semiconductor, a circular waveguide three-port network and a movable short plane, with the capability to adjust the S-parameters before and after switching. The RF properties of the switch module were analyzed. We give the scaling laws of the multiple-element switch systems, which allow the expansion of the system to a higher power level. We present a novel overmoded design for the circular waveguide three-port network and the associated circular-to-rectangular mode-converter. We also detail the design and synthesis process of this novel mode-converter. We demonstrate an electrically controlled ultra-fast high power X-band RF active window built with PIN diodes on high resistivity silicon. The window is capable of handling multi-megawatt RF power and can switch in 2-300ns with a 1000A current driver. A low power active pulse compression experiment was carried out with the switch module and a 375ns resonant delay line, obtaining 8 times compression gain with a compression ratio of 20.

  15. High gain 1310nm Raman amplifier (withdrawal notice)

    Science.gov (United States)

    CzyŻak, Paweł; Turkiewicz, Jarosław Piotr; Mazurek, Paweł

    2014-05-01

    This paper has been withdrawn. The following nearly identical paper is available in this conference proceedings: Jarosław Piotr Turkiewicz and Paweł Czyżak, "The high gain 1310nm Raman amplifier," Proc. SPIE 9228, Optical Fibers and Their Applications 2014, 92280P (May 12, 2014); doi:10.1117/12.2067055.

  16. JAERI 10kW High Power ERL-FEL and Its Applications in Nuclear Energy Industries

    CERN Document Server

    Minehara, E J; Iijima, H; Kikuzawa, N; Nagai, R; Nishimori, N; Nishitani, T; Sawamura, M; Yamauchi, T

    2005-01-01

    The JAERI high power ERL-FEL has been extended to the more powerful and efficient free-electron laser (FEL) than 10kW for nuclear energy industries, and other heavy industries like defense, shipbuilding, chemical industries, environmental sciences, space-debris, and power beaming and so on. In order to realize such a tunable, highly-efficient, high average power, high peak power and ultra-short pulse FEL, we need the efficient and powerful FEL driven by the JAERI compact, stand-alone and zero boil-off super-conducting RF linac with an energy-recovery geometry. Our discussions on the ERL-FEL will cover the current status of the 10kW upgrading and its applications of non-thermal peeling, cutting, and drilling to decommission the nuclear power plants, and to demonstrate successfully the proof of principle prevention of cold-worked stress-corrosion cracking failures in nuclear power reactors under routine operation using small cubic low-Carbon stainless steel samples.

  17. A new circuit topology using Z-source resonant inverter for high power contactless power transfer applications

    Directory of Open Access Journals (Sweden)

    Ghosh Prabhat Chandra

    2017-12-01

    Full Text Available In this study, a new circuit topology using a Z-source resonant inverter (ZSRI for high power applications in large-air-gap contactless power transfer (CPT systems, has been investigated. The main shortcoming of a large-air-gap CPT system is the poor power transfer efficiency due to low magnetic coupling. In order to minimize this shortcoming and to improve the overall performance of the system by boosting the power transfer capability, in this paper a CPT system with the newly developed circuit topology using high frequency Z-source resonant inverter has been proposed. Using the newly developed circuit topology for the CPT system, it has been observed that the overall performance of the system has been improved to a reasonable level with a purely sinusoidal resonant current flowing through the primary side. Therefore, no harmonics will be injected into the source. The proposed CPT system with an air gap of 16 cm and a misalignment of 3 cm has been simulated using the Maxwell finite element tool and Simplorer circuit simulation software for an output power of 2 kW.

  18. Monotron and azimuthally corrugated: application to the high power microwaves generation; Monotron e cavidades azimutalmente corrugadas: aplicacao a geracao de microondas de alta potencia

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Pedro Jose de

    2003-07-01

    The present document reports the activity of construction and initial operation of 6.7 GHz operation for high power microwave generation, the study on cylindrical resonators with azimuthally corrugated cross section, the determination of electrical conductivity of metallic materials and development of dielectric resonators for telecommunication applications.

  19. High power coaxial ubitron

    Science.gov (United States)

    Balkcum, Adam J.

    In the ubitron, also known as the free electron laser, high power coherent radiation is generated from the interaction of an undulating electron beam with an electromagnetic signal and a static periodic magnetic wiggler field. These devices have experimentally produced high power spanning the microwave to x-ray regimes. Potential applications range from microwave radar to the study of solid state material properties. In this dissertation, the efficient production of high power microwaves (HPM) is investigated for a ubitron employing a coaxial circuit and wiggler. Designs for the particular applications of an advanced high gradient linear accelerator driver and a directed energy source are presented. The coaxial ubitron is inherently suited for the production of HPM. It utilizes an annular electron beam to drive the low loss, RF breakdown resistant TE01 mode of a large coaxial circuit. The device's large cross-sectional area greatly reduces RF wall heat loading and the current density loading at the cathode required to produce the moderate energy (500 keV) but high current (1-10 kA) annular electron beam. Focusing and wiggling of the beam is achieved using coaxial annular periodic permanent magnet (PPM) stacks without a solenoidal guide magnetic field. This wiggler configuration is compact, efficient and can propagate the multi-kiloampere electron beams required for many HPM applications. The coaxial PPM ubitron in a traveling wave amplifier, cavity oscillator and klystron configuration is investigated using linear theory and simulation codes. A condition for the dc electron beam stability in the coaxial wiggler is derived and verified using the 2-1/2 dimensional particle-in-cell code, MAGIC. New linear theories for the cavity start-oscillation current and gain in a klystron are derived. A self-consistent nonlinear theory for the ubitron-TWT and a new nonlinear theory for the ubitron oscillator are presented. These form the basis for simulation codes which, along

  20. SiC/GaN Based Optically Triggered MESFET for High Power Efficiency and High Radiation Resistance Solid State Switch Application for Actuator System

    Science.gov (United States)

    2016-06-23

    High Radiation Resistance Solid State Switch Application for Actuator System The views, opinions and/or findings contained in this report are those of...Final Report: SiC/GaN Based Optically Triggered MESFET for High Power Efficiency and High Radiation Resistance Solid State Switch Application for...performed by the reactive ion etching (RIE) of silicon carbide in fluorinated -gas (CHF3, CBrF3, CF4, SF6 and NF3) plasma and inductively coupled plasma

  1. Optics assembly for high power laser tools

    Science.gov (United States)

    Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.

    2016-06-07

    There is provided a high power laser rotational optical assembly for use with, or in high power laser tools for performing high power laser operations. In particular, the optical assembly finds applications in performing high power laser operations on, and in, remote and difficult to access locations. The optical assembly has rotational seals and bearing configurations to avoid contamination of the laser beam path and optics.

  2. Analysis of High-Power Diode Laser Heating Effects on HY-80 Steel for Laser Assisted Friction Stir Welding Applications

    Energy Technology Data Exchange (ETDEWEB)

    Wiechec, Maxwell; Baker, Brad; McNelley, Terry; Matthews, Manyalibo; Rubenchik, Alexander; Rotter, Mark; Beach, Ray; Wu, Sheldon

    2017-01-01

    In this research, several conditions of high power diode laser heated HY-80 steel were characterized to determine the viability of using such lasers as a preheating source before friction stir welding in order to reduce frictional forces thereby reducing tool wear and increasing welding speeds. Differences in microstructures within heat affected zones were identified at specific laser powers and traverse speeds. Vickers hardness values were recorded and analyzed to validate the formation of additional martensite in diode laser heated regions of HY-80 steel. Conditions that produced little to no additional martensite were identified and relationships among high power diode laser power, traverse speed, and martensite formation were determined. The development of heat affected zones, change in grain structure, and creation of additional martensite in HY-80 can be prevented through the optimization of laser amperage and transverse speed.

  3. Applicability of STEM-RTG and High-Power SRG Power Systems to the Discovery and Scout Mission Capabilities Expansion (DSMCE) Study of ASRG-Based Missions

    Science.gov (United States)

    Colozza, Anthony J.; Cataldo, Robert L.

    2015-01-01

    This study looks at the applicability of utilizing the Segmented Thermoelectric Modular Radioisotope Thermoelectric Generator (STEM-RTG) or a high-power radioisotope generator to replace the Advanced Stirling Radioisotope Generator (ASRG), which had been identified as the baseline power system for a number of planetary exploration mission studies. Nine different Discovery-Class missions were examined to determine the applicability of either the STEM-RTG or the high-power SRG power systems in replacing the ASRG. The nine missions covered exploration across the solar system and included orbiting spacecraft, landers and rovers. Based on the evaluation a ranking of the applicability of each alternate power system to the proposed missions was made.

  4. Heavily Tm3+-Doped Silicate Fiber for High-Gain Fiber Amplifiers

    OpenAIRE

    Yin-Wen Lee; Han-Wei Chien; Che-Hung Cho; Ju-Zhe Chen; Juin-Shin Chang; Shibin Jiang

    2013-01-01

    We report on investigation the potential of a 7 wt% (8.35 × 1020 Tm3+/cm3) doped silicate fibers for high-gain fiber amplifiers. Such a high ion concentration significantly reduces the required fiber length of high-power 2 μm fiber laser systems and allows the high-repetition rate operation in 2 μm mode-locked fiber lasers. To evaluate the feasibility of extracting high gain-per-unit-length from this gain medium, we measure several key material properties of the silicate fiber, including the ...

  5. High power neutron production targets

    Energy Technology Data Exchange (ETDEWEB)

    Wender, S. [Los Alamos National Lab., NM (United States)

    1996-06-01

    The author describes issues of concern in the design of targets and associated systems for high power neutron production facilities. The facilities include uses for neutron scattering, accelerator driven transmutation, accelerator production of tritium, short pulse spallation sources, and long pulse spallation sources. Each of these applications requires a source with different design needs and consequently different implementation in practise.

  6. High-Efficiency Isolated Boost DCDC Converter for High-Power Low-Voltage Fuel-Cell Applications

    DEFF Research Database (Denmark)

    Nymand, Morten; Andersen, Michael A. E.

    2010-01-01

    of the primary-switch voltage rating can thus be avoided, significantly reducing switch-conduction losses. Finally, silicon carbide rectifying diodes allow fast diode turn-off, further reducing losses. Detailed test results from a 1.5-kW full-bridge boost dc-dc converter verify the theoretical analysis......A new design approach achieving very high conversion efficiency in low-voltage high-power isolated boost dc-dc converters is presented. The transformer eddy-current and proximity effects are analyzed, demonstrating that an extensive interleaving of primary and secondary windings is needed to avoid...... and demonstrate very high conversion efficiency. The efficiency at minimum input voltage and maximum power is 96.8%. The maximum efficiency of the proposed converter is 98%....

  7. High-power broadband Yb-free clad-pumped EDFA for L-band DWDM applications.

    Science.gov (United States)

    Zhu, Benyuan; Law, Matthew; Rooney, John; Shenk, Scott; Yan, Man F; DiGiovanni, David J

    2014-01-01

    We demonstrated high-power broadband Yb-free clad-pumped erbium-doped fiber amplifier (EDFA) using commercial available low-cost 976 nm multimode diodes. An output power +33 dBm with less than ±1 dB natural gain flatness over a gain bandwidth of 33 nm (1570.3-1603.3 nm) was obtained using a new double-clad erbium-doped fiber which has a large core diameter of 17 μm and low NA of 0.11. The saturated output power, net gain, noise figure, and optical power conversion efficiency of the clad-pumped EDFA were characterized, and system impact of LP11 mode and four-wave-mixing nonlinearity were also evaluated.

  8. Multiple-pass amplifiers for high-power laser systems

    Energy Technology Data Exchange (ETDEWEB)

    Jackel, S.; Givon, M.; Ludmirsky, A.; Eliezer, S.; Borowitz, J.L.; Arad, B.; Zigler, A.; Gazit, Y.

    1987-02-01

    Multiple-pass amplifiers were configured from Nd:glass rods using polarization and angular coupling techniques. Very high gain (>600) single beam triple-pass booster stages and high gain (30 or 15) single or double-beam double-pass amplifiers were combined to construct a very cost effective high-power (50 GW) pulsed laser system. These techniques were also effectively applied to smaller compact high repetition-rate systems.

  9. High gain high efficiency resonant DC-DC converter

    Science.gov (United States)

    Shang, Fei

    Low voltage power sources have played an important role in applications such as automotive system, renewable energy power generation and so on, where require a high gain DC-DC step-up converter. The converter is going to sustain a very high input current which can bring many design challenges in the existing topologies, such as high component current stress and power loss, complex and costly design for magnetic components, high input current ripple, etc. A new topology of high gain DCDC step-up converter proposed in this dissertation. The topology has many merits such as high gain capability, high efficiency, low components stress and requirement of the transformer, simple topology with less number of active switching devices, and easy to control. The dissertation carries out theoretical analysis of the proposed topology under different operating modes and the voltage gain has been deduced for each mode. The design of circuit components has been well studied, including the power devices current stress and power, the selection of transformer turns-ratio, the design method of the resonant tank and input current ripple. System dynamic state-space models are acquired by using generalized averaging method. Small signal model of the converter is achieved by linearization of the dynamic model around the operating points. The stability study indicates that the open loop system is stable at all operating points, except some operating points containing RHP zeros which can cause closed loop system unstable. The parameter sensitivity study shows that the system transfer function is not greatly affected by the variation of the leakage inductance and load resistance. A design of PI controller is implemented to achieve the output voltage regulation. Simulations have been carried out to validate the circuit operation and support the design analysis. A 2kW prototype has been built for experimental testing. The experimental results are in a good agreement with the theoretical

  10. High Power Vanadate lasers

    CSIR Research Space (South Africa)

    Strauss, HJ

    2006-07-01

    Full Text Available This presentation aims at the following: to develop new techniques to mount laser crystals; compare the laser properties of two equally doped, high power Nd:YVO4 and Nd: GdVO4 lasers; build a 1um vanadate laser with average output power exceeding...

  11. Packaging of high power semiconductor lasers

    CERN Document Server

    Liu, Xingsheng; Xiong, Lingling; Liu, Hui

    2014-01-01

    This book introduces high power semiconductor laser packaging design. The characteristics and challenges of the design and various packaging, processing, and testing techniques are detailed by the authors. New technologies, in particular thermal technologies, current applications, and trends in high power semiconductor laser packaging are described at length and assessed.

  12. Self-sustainable, high-power-density bio-solar cells for lab-on-a-chip applications.

    Science.gov (United States)

    Liu, Lin; Choi, Seokheun

    2017-11-07

    A microfluidic lab-on-a-chip system that generates its own power is essential for stand-alone, independent, self-sustainable point-of-care diagnostic devices to work in limited-resource and remote regions. Miniaturized biological solar cells (or micro-BSCs) can be the most suitable power source for those lab-on-a-chip applications because the technique resembles the earth's natural ecosystem - living organisms work in conjunction with non-living components of their environment to create a self-assembling and self-maintaining system. Micro-BSCs can continuously generate electricity from microbial photosynthetic and respiratory activities over day-night cycles, offering a clean and renewable power source with self-sustaining potential. However, the promise of this technology has not been translated into practical applications because of its relatively low power (∼nW cm -2 ) and current short lifetimes (∼a couple of hours). In this work, we enabled high-performance, self-sustaining, long-life micro-BSCs by using fundamental breakthroughs of device architectures and electrode materials. A 3-D biocompatible, conductive, and porous anode demonstrated great microbial biofilm formation and a high rate of bacterial extracellular electron transfer, which led to greater power generation. Furthermore, our micro-BSCs promoted gas exchange to the bacteria through a gas-permeable PDMS membrane in a well-controlled, tightly enclosed micro-chamber, substantially enhancing sustainability. Through photosynthetic reactions of the cyanobacteria Synechocystis sp. PCC 6803 without additional organic fuel, the 90 μL single-chambered bio-solar cell generated a maximum power density of 43.8 μW cm -2 and sustained consistent power production of ∼18.6 μW cm -2 during the day and ∼11.4 μW cm -2 at night for 20 days, which is the highest and longest reported success of any existing micro-scale bio-solar cells.

  13. Concept, Design, and Prototyping of XSAS: A High Power Extendable Solar Array for CubeSat Applications

    Science.gov (United States)

    Senatore, Patrick; Klesh, Andrew; Zurbuchen, Thomas H.; McKague, Darren; Cutler, James

    2010-01-01

    CubeSats have proven themselves as a reliable and cost-effective method to perform experiments in space, but they are highly constrained by their specifications and size. One such constraint is the average continuous power, about 5 W, which is available to the typical CubeSat. To improve this constraint, we have developed the eXtendable Solar Array System (XSAS), a deployable solar array prototype in a CubeSat package, which can provide an average 23 W of continuous power. The prototype served as a technology demonstrator for the high risk mechanisms needed to release, deploy, and control the solar array. Aside from this drastic power increase, it is in the integration of each mechanism, their application within the small CubeSat form-factor, and the inherent passive control benefit of the deployed geometry that make XSAS a novel design. In this paper, we discuss the requirements and design process for the XSAS system and mechanical prototype, and provide qualitative and quantitative results from numerical simulations and prototype tests. We also discuss future work, including an upcoming NASA zero-gravity flight campaign, to further improve on XSAS and prepare it for future launch opportunities.

  14. High-power electronics

    CERN Document Server

    Kapitsa, Petr Leonidovich

    1966-01-01

    High-Power Electronics, Volume 2 presents the electronic processes in devices of the magnetron type and electromagnetic oscillations in different systems. This book explores the problems of electronic energetics.Organized into 11 chapters, this volume begins with an overview of the motion of electrons in a flat model of the magnetron, taking into account the in-phase wave and the reverse wave. This text then examines the processes of transmission of electromagnetic waves of various polarization and the wave reflection from grids made of periodically distributed infinite metal conductors. Other

  15. Design of Single-Stage AC/DC Converter with High Efficiency and High Power Factor for Low Power Level Applications

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jun Young; Moon, Gun Woo; Youn, Myung Joong [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1997-06-01

    Design of single stage AC/DC converter with high power factor for low power level applications is proposed. The proposed converter gives the good power factor correction, low line current harmonic distortions, and tight output voltage regulations. This converter also has a high efficiency by employing an active clamp method and synchronous rectifiers. To verify the performance of the proposed converter, a 90W-converter has been designed. The modelling of this proposed converter is performed using an averaging technique and based on this model, a detailed analysis is carried out. This prototype meets the IEC555-2 requirements satisfactorily with nearly unity power factor and high efficiency. (author). 9 refs., 16 figs.

  16. Design and properties of high-power highly-coherent single-frequency VECSEL emitting in the near- to mid-IR for photonic applications

    Science.gov (United States)

    Garnache, A.; Laurain, A.; Myara, M.; Sellahi, M.; Cerutti, L.; Perez, J. P.; Michon, A.; Beaudoin, G.; Sagnes, I.; Cermak, P.; Romanini, D.

    2017-11-01

    We demonstrate high power (multiwatt) low noise single frequency operation of tunable compact verical-external- cavity surface-emitting-lasers exhibiting a low divergence high beam quality, of great interest for photonics applications. The quantum-well based lasers are operating in CW at RT at 1μm and 2.3μm exploiting GaAs and Sb technologies. For heat management purpose the VECSEL membranes were bonded on a SiC substrate. Both high power diode pumping (using GaAs commercial diode) at large incidence angle and electrical pumping are developed. The design and physical properties of the coherent wave are presented. We took advantage of thermal lens-based stability to develop a short (0.5-5mm) external cavity without any intracavity filter. We measured a low divergence circular TEM00 beam (M2 = 1.2) close to diffraction limit, with a linear light polarization (> 30 dB). The side mode suppression ratio is > 45 dB. The free running laser linewidth is 37 kHz limited by pump induced thermal fluctuations. Thanks to this high-Q external cavity approach, the frequency noise is low and the dynamics is in the relaxation-oscillation-free regime, exhibiting low intensity noise (< 0.1%), with a cutoff frequency ∽ 41MHz above which the shot noise level is reached. The key parameters limiting the laser power and coherence will be discussed. These design/properties can be extended to other wavelengths.

  17. Resonant High Power Combiners

    CERN Document Server

    Langlois, Michel; Peillex-Delphe, Guy

    2005-01-01

    Particle accelerators need radio frequency sources. Above 300 MHz, the amplifiers mostly used high power klystrons developed for this sole purpose. As for military equipment, users are drawn to buy "off the shelf" components rather than dedicated devices. IOTs have replaced most klystrons in TV transmitters and find their way in particle accelerators. They are less bulky, easier to replace, more efficient at reduced power. They are also far less powerful. What is the benefit of very compact sources if huge 3 dB couplers are needed to combine the power? To alleviate this drawback, we investigated a resonant combiner, operating in TM010 mode, able to combine 3 to 5 IOTs. Our IOTs being able to deliver 80 kW C.W. apiece, combined power would reach 400 kW minus the minor insertion loss. Values for matching and insertion loss are given. The behavior of the system in case of IOT failure is analyzed.

  18. High power switching and other high power devices

    Science.gov (United States)

    Gundersen, Martin

    1992-09-01

    High power thyratrons and devices such as high power microwave sources have cathode-related performance limits. Research is described of a simple, robust 'super-emissive' cathode that produces greater than 10,000 A/sq cm from a macroscopic area (approx. 1 sq cm), and operates with a low pressure (approx. 0.1 torr), spatially uniform glow plasma (density greater than 1015 cu cm). The cathode also can operate as a hollow cathode, and is at the heart of the operation of the pseudospark and back-lighted thyratron. The physics of this hollow and super-emissive cathode is very rich. The hollow cathode geometry traps electrons in the hollow cathode backspace. The lifetime of these electrons enables them to ionize a spatially homogeneous high density glow, and this hollow cathode mode of operation is responsible for certain types of electron and ion beam behavior. A plasma cathode sheath that is formed during this phase leads to super-emissive behavior, which is responsible for high current emission. Super-emissive cathode thyratron-type switches (with higher peak current, voltage, di/dt) being developed for pulsed power switching of lasers, accelerators, high current and high coulomb transfer, Marx bank operation, transfer of technology to commercial applications, high current electron beams, and millimeter wave generation (1 to 100 GHz) are described.

  19. A Unified Approach to High-Gain Adaptive Controllers

    Directory of Open Access Journals (Sweden)

    Ian A. Gravagne

    2009-01-01

    Full Text Available It has been known for some time that proportional output feedback will stabilize MIMO, minimum-phase, linear time-invariant systems if the feedback gain is sufficiently large. High-gain adaptive controllers achieve stability by automatically driving up the feedback gain monotonically. More recently, it was demonstrated that sample-and-hold implementations of the high-gain adaptive controller also require adaptation of the sampling rate. In this paper, we use recent advances in the mathematical field of dynamic equations on time scales to unify and generalize the discrete and continuous versions of the high-gain adaptive controller. We prove the stability of high-gain adaptive controllers on a wide class of time scales.

  20. Recent Progress in High-Gain FEL Theory

    CERN Document Server

    Huang, Z

    2005-01-01

    High-gain free electron lasers (FEL) are being developed as extremely bright x-ray sources of a next-generation radiation facility. In this paper, we review the basic theory and the recent progress in understanding the startup, the exponential growth and the saturation of the high-gain process, emphasizing the self-amplified spontaneous emission (SASE). We will also discuss how the FEL performance may be affected by various errors and wakefield effects in the undulator.

  1. Recent Progress in High-Gain FEL Theory

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z.; /SLAC

    2005-09-30

    High-gain free electron lasers (FEL) are being developed as extremely bright x-ray sources of a next-generation radiation facility. In this paper, we review the basic theory and the recent progress in understanding the startup, the exponential growth and the saturation of the high-gain process, emphasizing the self-amplified spontaneous emission (SASE). We will also discuss how the FEL performance may be affected by various errors and wakefield effects in the undulator.

  2. Thermal latency adds to lesion depth after application of high-power short-duration radiofrequency energy: Results of a computer-modeling study.

    Science.gov (United States)

    Irastorza, Ramiro M; d'Avila, Andre; Berjano, Enrique

    2018-02-01

    The use of ultra-short RF pulses could achieve greater lesion depth immediately after the application of the pulse due to thermal latency. A computer model of irrigated-catheter RF ablation was built to study the impact of thermal latency on the lesion depth. The results showed that the shorter the RF pulse duration (keeping energy constant), the greater the lesion depth during the cooling phase. For instance, after a 10-second pulse, lesion depth grew from 2.05 mm at the end of the pulse to 2.39 mm (17%), while after an ultra-short RF pulse of only 1 second the extra growth was 37% (from 2.22 to 3.05 mm). Importantly, short applications resulted in deeper lesions than long applications (3.05 mm vs. 2.39 mm, for 1- and 10-second pulse, respectively). While shortening the pulse duration produced deeper lesions, the associated increase in applied voltage caused overheating in the tissue: temperatures around 100 °C were reached at a depth of 1 mm in the case of 1- and 5-second pulses. However, since the lesion depth increased during the cooling period, lower values of applied voltage could be applied in short durations in order to obtain lesion depths similar to those in longer durations while avoiding overheating. The thermal latency phenomenon seems to be the cause of significantly greater lesion depth after short-duration high-power RF pulses. Balancing the applied total energy when the voltage and duration are changed is not the optimal strategy since short pulses can also cause overheating. © 2017 Wiley Periodicals, Inc.

  3. High power evaluation of X-band high power loads

    CERN Document Server

    Matsumoto, Shuji; Syratchev, Igor; Riddone, Germana; Wuensch, Walter

    2010-01-01

    Several types of X-band high power loads developed for several tens of MW range were designed, fabricated and used for high power tests at X-band facility of KEK. Some of them have been used for many years and few units showed possible deterioration of RF performance. Recently revised-design loads were made by CERN and the high power evaluation was performed at KEK. In this paper, the main requirements are recalled, together with the design features. The high power test results are analysed and presented

  4. High power lasers

    CERN Document Server

    Niku-Lari, A

    1989-01-01

    The use of lasers for the working and treatment of materials is becoming increasingly common in industry. However, certain laser applications, for example, in welding, cutting and drilling, are more widely exploited than others. Whilst the potential of lasers for the surface treatment of metals is well recognised, in practice, this particular application is a relative newcomer. The 24 papers in this volume present the latest research and engineering developments in the use of lasers for processes such as surface melting, surface alloying and cladding, and machining, as well as discussing th

  5. High power lasers & systems

    OpenAIRE

    Chatwin, Chris; Young, Rupert; Birch, Philip

    2015-01-01

    Some laser history;\\ud Airborne Laser Testbed & Chemical Oxygen Iodine Laser (COIL);\\ud Laser modes and beam propagation;\\ud Fibre lasers and applications;\\ud US Navy Laser system – NRL 33kW fibre laser;\\ud Lockheed Martin 30kW fibre laser;\\ud Conclusions

  6. High Power Electrochemical Capacitors

    Science.gov (United States)

    2012-03-23

    and Cu surfaces using trimethylamine alane (TMAA) as an organometallic CVD precursor. For this project we further demonstrated that the ALD deposition...this work, we show how the application of nanodiamond (ND) can greatly increase the performance of electrochemically active polymers , such as

  7. High-gain Seeded FEL Amplifier Tunable in the Terahertz Range

    CERN Document Server

    Sung, C; Pellegrini, C; Ralph, J E; Reiche, S; Rosenzweig, J B; Tochitsky, Sergei Ya

    2005-01-01

    The lack of a high-power, relatively low-cost and compact terahertz (THz) source in the range 0.3-3x10(12) Hz is the major obstacle in progressing on biomedical and material studies at these wavelengths. A high-gain, single pass seeded FEL technique allows to obtain high power THz pulses of a high spectral brightness. We describe an ongoing project at the Neptune laboratory where a ~ 1kW seed pulse generated by difference frequency mixing of CO2 laser lines in a GaAs nonlinear crystal is injected into a waveguide FEL amplifier. The FEL is driven by a 5 ps (r.m.s) long electron pulse with a peak current up to 100A provided by a regular S-band photoinjector. According to 3-D, time dependent simulations, up to ~ 10 MW THz power can be generated using a 2 meter long planar undulator. By mixing different pairs of CO2 laser lines and matching resonant energy of the electron beam, tunability in the 100-400 mm range is expected. A tunable Fabri-Perot interferometer will be used to select a high-power 5ps THz pulse. T...

  8. Modeling of high gain helical antenna for improved performance ...

    African Journals Online (AJOL)

    The modeling of High Gain Helical Antenna structure is subdivided into three sections : introduction of helical structures ,Numerical analysis, modeling and simulation based on the parameters of helical antenna. The basic foundation software for the research paper is Matlab technical computing software, the modeling were ...

  9. Development of a 233 GHz High Gain Traveling Wave Amplifier

    Science.gov (United States)

    2014-04-22

    and the design is robust to expected alignment tolerances. The input window will be the same construction as the 220 GHz TWT program [5]: A pill-box...Int’l Vac. Elec. Conf., Paris, France, 21-23 May 2013. 4. K. T. Nguyen, et al., “Design of a 233 GHz High-Gain Single-Stage Hybrid-Serpentine TWT

  10. In-volume heating using high-power laser diodes

    NARCIS (Netherlands)

    Denisenkov, V.S.; Kiyko, V.V.; Vdovin, G.V.

    2015-01-01

    High-power lasers are useful instruments suitable for applications in various fields; the most common industrial applications include cutting and welding. We propose a new application of high-power laser diodes as in-bulk heating source for food industry. Current heating processes use surface

  11. high power facto high power factor high power factor hybrid rectifier

    African Journals Online (AJOL)

    eobe

    compact and efficient new devices, it noted increase in the number of electrical loads that some kind of electronic ... in electric machines and capacitors,. HIGH POWER FACTOR. HIGH POWER FACTOR HYBRID ...... Auxiliary DC-DC Converter for Hybrid Vehicles ”,. IEEE Transactions on Power Electronics vol. 23, no. 6, pp.

  12. High Power Orbit Transfer Vehicle

    National Research Council Canada - National Science Library

    Gulczinski, Frank

    2003-01-01

    ... from Virginia Tech University and Aerophysics, Inc. to examine propulsion requirements for a high-power orbit transfer vehicle using thin-film voltaic solar array technologies under development by the Space Vehicles Directorate (dubbed PowerSail...

  13. Heavily Tm3+-Doped Silicate Fiber for High-Gain Fiber Amplifiers

    Directory of Open Access Journals (Sweden)

    Yin-Wen Lee

    2013-12-01

    Full Text Available We report on investigation the potential of a 7 wt% (8.35 × 1020 Tm3+/cm3 doped silicate fibers for high-gain fiber amplifiers. Such a high ion concentration significantly reduces the required fiber length of high-power 2 μm fiber laser systems and allows the high-repetition rate operation in 2 μm mode-locked fiber lasers. To evaluate the feasibility of extracting high gain-per-unit-length from this gain medium, we measure several key material properties of the silicate fiber, including the absorption/emission cross-sections, upper-state lifetime, fiber background loss, and photodarkening resistance. We show through numerical simulations that a signal gain-per-unit-length of 3.78 dB/cm at 1950 nm can be achieved in a watt-level core-pumped Tm3+-doped silicate fiber amplifier. In addition, an 18-dB 2013-nm amplifier is demonstrated in a 50-cm 7 wt% Tm3+-doped double-clad silicate fiber. Finally, we experimentally confirm that the reported silicate host exhibits no observable photodarkening.

  14. Design and Study of a DC/DC Converter for High Power, 14.4 V and 300 A for Automotive Applications

    OpenAIRE

    Julio Cesar Lopes de Oliveira; Carlos Henrique Gonc¸alves Treviso

    2014-01-01

    The shortage of the automotive market in relation to options for sources of high power car audio systems, led to development of this work. Thus, we developed a source with stabilized voltage with 4320 W effective power. Designed to the voltage of 14.4 V and a choice of two currents: 30 A load option in battery banks and 300 A at full load. This source can also be considered as a source of general use dedicated commercial with a simple control circuit in analog form based ...

  15. High-power downhole motor

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, J.H.; Maurer, W.C.; Evans, C.R. [Maurer Engineering Inc., Houston, TX (United States); Westcott, P.A. [Gas Research Inst., Chicago, IL (United States)

    1995-12-31

    New high power motors are being developed by the Gas Research Institute (GRI) in an attempt to reduce drilling costs in deep gas wells. Conventional 2 3/8-in. (60-mm) and 3 3/8-in. (86-mm) motors operated in overpowered conditions (i.e., high flow rates and high differential pressures) drill 2 to 3 times faster than conventional motors. A new high-power 3 3/8-in. (86-mm) motor is being developed that utilizes additional stages and tighter interference between the rotor and stator to increase motor pressure drop, torque, and power output. This new high-power motor delivers up to 238 hp (177 kW) compared to 50 hp (37 kW) for a conventional 3 3/8-in. (86-mm) motor operating at rated operating conditions. Temperature probes showed that temperatures in different stages of motors vary considerably, showing that some sections do more work than others. A better understanding of temperatures within the stators is needed because thermal degradation and ``chunking`` of the rubber is a leading cause of failures in motors operating at high power levels. These tests were very encouraging, demonstrating the feasibility of developing reliable, high-power motors.

  16. High gain and low excess noise near infrared single photon avalanche detector

    Science.gov (United States)

    Linga, Krishna; Yevtukhov, Yuriy; Liang, Bing

    2009-05-01

    We present the discrete amplification approach used for development of a very high gain and low excess noise factor in the near infrared wavelength region. The devices have the following performance characteristics: gain > 2X105, excess noise factor researchers in the fields of deep space optical communication, spectroscopy, industrial and scientific instrumentation, Ladar/Lidar, quantum cryptography, night vision and other military, defense and aerospace applications.

  17. C-band 10-Watt HBT high-power amplifier with 50% PAE

    NARCIS (Netherlands)

    Hek, A.P. de; Boer, A. de; Svensson, T.

    2001-01-01

    The design and measurement of a C-band HBT high-power amplifier (HPA) is discussed. The amplifier is realised in the HB20P power HBT process of UMS. The HPA combines a high average output power of 9 Watt with both a high gain of 21.6 dB and a high power added effciency (PAE) of 50% over about 20%

  18. High-Gain High-Field Fusion Plasma

    Science.gov (United States)

    Li, Ge

    2015-01-01

    A Faraday wheel (FW)—an electric generator of constant electrical polarity that produces huge currents—could be implemented in an existing tokamak to study high-gain high-field (HGHF) fusion plasma, such as the Experimental Advanced Superconducting Tokamak (EAST). HGHF plasma can be realized in EAST by updating its pulsed-power system to compress plasma in two steps by induction fields; high gains of the Lawson trinity parameter and fusion power are both predicted by formulating the HGHF plasma. Both gain rates are faster than the decrease rate of the plasma volume. The formulation is checked by earlier ATC tests. Good agreement between theory and tests indicates that scaling to over 10 T at EAST may be possible by two-step compressions with a compression ratio of the minor radius of up to 3. These results point to a quick new path of fusion plasma study, i.e., simulating the Sun by EAST. PMID:26507314

  19. Terahertz radiation source using a high-power industrial electron ...

    Indian Academy of Sciences (India)

    We propose that high-power electron beam from such an industrial linac can first pass through an undulator to generate useful terahertz (THz) radiation, and the spent electron beam coming out of the undulator can still be used for the intended industrial applications. This will enhance the utilization of a high-power industrial ...

  20. High temperature, high power piezoelectric composite transducers.

    Science.gov (United States)

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-08-08

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  1. An introduction to high power microwaves

    Science.gov (United States)

    Benford, James; Swegle, John

    1992-02-01

    The area of high power microwaves has emerged in recent years as a new technology allowing new applications and offering innovative approaches to existing applications. The great leap in microwave power levels has been driven by a mix of sources that either push conventional microwave device physics in new directions or employ altogether new interaction mechanisms. Running counter to the trend in conventional microwave electronics toward miniaturization with solid-state devices intrinsically limited in their peak power capability, high power microwave generation taps the immense power and energy reservoirs of modern intense relativistic electron beam technology. The term high power microwaves (HPM) is used to denote devices that exceed 100 MW in peak power and span the cm- and mm-wave range of frequencies between 1 and 300 GHz. This definition is arbitrary, but does cleanly divide the conventional microwave devices, which do not exceed 100 MW, from a collection of microwave-generating devices that have now reached powers as high as 15 GW.

  2. Methods for High Power EM Pulse Measurement

    Directory of Open Access Journals (Sweden)

    P. Fiala

    2006-12-01

    Full Text Available There are some suitable methods for the measurement of ultra-short solitary electromagnetic pulses that can be generated by high power pulsed generators. The measurement methods properties have to correspond to the fact whether we want to measure pulses of voltage, current or free-space electromagnetic wave. The need for specific measurement methods occurred by the development of high power microwave pulse generator. Applicable methods are presented in this paper. The method utilizing Faraday's induction law allows the measurement of generated current. For the same purpose the magneto-optic method can be utilized, with its advantages. For measurement of output microwave pulse of the generator the calorimetric method was designed and realized.

  3. High power gas laser amplifier

    Science.gov (United States)

    Leland, Wallace T.; Stratton, Thomas F.

    1981-01-01

    A high power output CO.sub.2 gas laser amplifier having a number of sections, each comprising a plurality of annular pumping chambers spaced around the circumference of a vacuum chamber containing a cold cathode, gridded electron gun. The electron beam from the electron gun ionizes the gas lasing medium in the sections. An input laser beam is split into a plurality of annular beams, each passing through the sections comprising one pumping chamber.

  4. A Comparative Study of Front and Back Illuminated Strain Balanced InGaAs MQW Thermophotovoltaic Cells on n-InP Substrate For High Power Applications

    Science.gov (United States)

    Ginige, Ravin; Corbett, Brian; Hilgarth, Just; Ballard, Ian; Abbott, Paul; Barnham, Keith; Mazzer, Massimo; Clarke, Graham

    2004-11-01

    We have processed and characterised front (P-Grid) and back (N-Grid) illuminated strain balanced multi-quantum well InGaAs/InP thermophotovoltaic cells with a bandedge at 1980nm. We find that the inverted cells (N-Grid) dark currents are comparable to the conventional (P-Grid) MQW cells and have power conversion efficiencies of 10% under AM0 incident radiation. Inverted cells are shown to have better performance at high power densities, with improved fill factors of 74% compared to 62-67% for conventional illumination. Inverted cell external quantum efficiencies were measured to be lower than that of the conventional cell due to different reflectance losses, while the internal quantum efficiencies were found to be similar. The percentage absorption per well in the inverted cell is 1% at the bandedge. These results suggest that quantum efficiency can be improved with optimised reflective back metallisation and with increased number of wells to absorb above bandgap incident light in two passes.

  5. High-power diode lasers between 1.8μm and 3.0μm for military applications

    Science.gov (United States)

    Hilzensauer, S.; Giesin, C.; Schleife, J.; Gilly, J.; Patterson, S.; Kelemen, M. T.

    2013-10-01

    Over the last years high-power diode lasers in the wavelength window between 1.8μm and 3.0μm have demonstrated impressive characteristics in terms of output power, beam quality and efficiency. This facilitates the realization of compact and efficient light sources for use in the field of infrared countermeasures (IRCM), optically pumped semiconductor lasers emitting in the 2-4μm regime, low probability of intercept communication links, and trace gas analysis. The small size of a diode laser chip of typically less than a square millimeter allows for the fabrication of compact scalable laser modules with output powers of up to 140W. We will present results on MBE grown (AlGaIn)(AsSb) quantum-well diode laser single emitters and bars emitting between 1.8μm and 3.0μm. Different epitaxial and resonator designs have been investigated in cw and pulsed mode in order to meet industrial needs of high wall-plug and fiber-coupling efficiencies. More than 30% maximum wall-plug efficiency in cw operation for single emitters and laser bars has been reached together with output powers for single emitters of 2W (cw) and 9W (pulsed). The single emitters and bars are all suitable for fiber coupling. For a 1-bar module typical coupling efficiencies between 70% and 80% have been established for 400μm core fibers. In terms of output power, an AuSn soldered laser stack built of 10x 20% fill factor bars emitting at 1908nm, results in a record value of 140W at 58A in cw condition.

  6. Design of mode converters from TE circular om modes in circular waveguides to TE rectangular mo modes in rectangular waveguides for high power applications in the frequency range 1 to 30 GHz

    Science.gov (United States)

    Janzen, G.

    1984-07-01

    A mode converter for transitions from circular symmetric modes to rectangular waveguide modes and vice versa for high power applications in plasma heating experiments is described. The converter conserves the power of all circular symmetric modes emitted by a gyrotron and aligns the fields into linearly polarized modes required for effective plasma heating by electron cyclotron or by lower hybrid resonance absorption. It also allows a convenient combination of the power output of several klystrons and mode conversion into modes with low attenuation. Suitable combinations of waveguide diameter and number of sectors dividing (or combining) the power avoid the excitation of unwanted modes.

  7. High Power UV LED Industrial Curing Systems

    Energy Technology Data Exchange (ETDEWEB)

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  8. Ultra-high gain diffusion-driven organic transistor

    Science.gov (United States)

    Torricelli, Fabrizio; Colalongo, Luigi; Raiteri, Daniele; Kovács-Vajna, Zsolt Miklós; Cantatore, Eugenio

    2016-01-01

    Emerging large-area technologies based on organic transistors are enabling the fabrication of low-cost flexible circuits, smart sensors and biomedical devices. High-gain transistors are essential for the development of large-scale circuit integration, high-sensitivity sensors and signal amplification in sensing systems. Unfortunately, organic field-effect transistors show limited gain, usually of the order of tens, because of the large contact resistance and channel-length modulation. Here we show a new organic field-effect transistor architecture with a gain larger than 700. This is the highest gain ever reported for organic field-effect transistors. In the proposed organic field-effect transistor, the charge injection and extraction at the metal–semiconductor contacts are driven by the charge diffusion. The ideal conditions of ohmic contacts with negligible contact resistance and flat current saturation are demonstrated. The approach is general and can be extended to any thin-film technology opening unprecedented opportunities for the development of high-performance flexible electronics. PMID:26829567

  9. Fast ignition integrated experiments and high-gain point design

    Energy Technology Data Exchange (ETDEWEB)

    Shiraga, H. [Osaka Univ., Osaka (Japan); Nagatomo, H. [Osaka Univ., Osaka (Japan); Theobald, W. [Univ. of Rochester, Rochester, NY (United States); Solodov, A. A. [Univ. of Rochester, Rochester, NY (United States); Tabak, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-04-17

    Here, integrated fast ignition experiments were performed at ILE, Osaka, and LLE, Rochester, in which a nanosecond driver laser implodes a deuterated plastic shell in front of the tip of a hollow metal cone and an intense ultrashort-pulse laser is injected through the cone to heat the compressed plasma. Based on the initial successful results of fast electron heating of cone-in-shell targets, large-energy short-pulse laser beam lines were constructed and became operational: OMEGA-EP at Rochester and LFEX at Osaka. Neutron enhancement due to heating with a ~kJ short-pulse laser has been demonstrated in the integrated experiments at Osaka and Rochester. The neutron yields are being analyzed by comparing the experimental results with simulations. Details of the fast electron beam transport and the electron energy deposition in the imploded fuel plasma are complicated and further studies are imperative. The hydrodynamics of the implosion was studied including the interaction of the imploded core plasma with the cone tip. Theory and simulation studies are presented on the hydrodynamics of a high-gain target for a fast ignition point design.

  10. Present and Future Trends in High Power Generation

    NARCIS (Netherlands)

    Heijster, R.M.E.M. van; Schouten, J.M.

    1995-01-01

    Modern warfare requires high levels of microwave power for various applications. Semiconductors are only suitable for low and medium power levels, for high power generation microwave tubes are still the most effective solution.

  11. A Coherent Compton Backscattering High Gain FEL using an X-Band Microwave Undulator

    CERN Document Server

    Pellegrini, C; Travish, G

    2005-01-01

    We describe a proposed high-gain FEL using an X-band microwave undulator and operating at a wavelength of about 0.5 μm. The FEL electron beam energy is 65 MeV. The beam is produced by the NLCTA X-band linac at SLAC, using an S-band high-brightness photoinjector. The undulator consists of a circular waveguide with an rf wave counter-propagating with respect to the electron beam. The undulator is powered with two high-power X-band klystrons and a dual-moded pulse compressor recently developed at SLAC. This system is capable of delivering flat-top rf pulses of up to 400 ns and a few hundred megawatts. The equivalent undulator period is 1.4 cm, the radius of the circular pipe is 1 cm, and the undulator parameter is about 0.4 for a helical undulator configuration, obtained using two cross-polarized TE modes, or larger for a planar configuration, using one rf polarization. The undulator is about four meters long. The FEL will reach saturation within this distance when operated in a SASE mode. We describe t...

  12. High-gain and low-excess noise near-infrared single-photon avalanche detector arrays

    Science.gov (United States)

    Linga, Krishna; Yevtukhov, Yuriy; Liang, Bing

    2010-04-01

    We have designed and developed a new family of photodetectors and arrays with Internal Discrete Amplification (IDA) mechanism for the realization of very high gain and low excess noise factor in the visible and near infrared spectral regions. These devices surpass many limitations of the Single Photon Avalanche Photodetectors such as ultra low excess noise factor, very high gain, lower reset time (researchers in the field of spectroscopy, industrial and scientific instrumentation, Ladar, quantum cryptography, night vision and other military, defense and aerospace applications.

  13. Fast sol-gel synthesis of LiFePO{sub 4}/C for high power lithium-ion batteries for hybrid electric vehicle application

    Energy Technology Data Exchange (ETDEWEB)

    Beninati, Sabina; Damen, Libero; Mastragostino, Marina [University of Bologna, Department of Metal Science, Electrochemistry and Chemical Techniques, Via San Donato 15, 40127 Bologna (Italy)

    2009-12-01

    LiFePO{sub 4}/C of high purity grade was successfully synthesized by microwave accelerated sol-gel synthesis and showed excellent electrochemical performance in terms of specific capacity and stability. This cathode material was characterized in battery configuration with a graphite counter electrode by USABC-DOE tests for power-assist hybrid electric vehicle. It yielded a non-conventional Ragone plot that represents complexity of battery functioning in power-assist HEV and shows that the pulse power capability and available energy of such a battery surpasses the DOE goal for such an application. (author)

  14. RF design and tests on a broadband, high-power coaxial quadrature hybrid applicable to ITER ICRF transmission line system for load-resilient operations

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hae Jin, E-mail: haejin@nfri.re.kr [National Fusion Research Institute, Daejeon (Korea, Republic of); Wang, Son Jong; Park, Byoung Ho; Kwak, Jong-Gu [National Fusion Research Institute, Daejeon (Korea, Republic of); Hillairet, Julien [CEA/IRFM, Saint-lez-Durance (France); Choi, Jin Joo [Kwangwoon University, Seoul (Korea, Republic of)

    2015-10-15

    Highlights: • Amplitude balanced 3 dB coaxial hybrid splitter has been designed and rf tested. • The proposed hybrid is applicable to ITER ICRF transmission line for load resilience. • Two-section, broadband coaxial hybrid can be tunable by changing dielectric insulator. - Abstract: RF design and network analyzer tests of broadband, amplitude-balanced coaxial hybrid junctions are presented. We have designed two 3 dB hybrid splitters with 9 and 12 in. coaxial transmission lines applicable to ITER ICRF for load-resilient operations using ANSYS HFSS. Amplitude-balanced broadband responses were obtained with the combination of impedance reductions of longitudinal and transverse branches in unequal proportion, length change of 50 Ω lines and diameter change of high impedance lines connected transversely to the T-section of the hybrid splitter, respectively. We have fabricated and RF tested the 9 in. coaxial hybrid coupler. We obtained an excellent coupling flatness of −3.2 ± 0.2 dB, phase difference of 4 degrees and return loss of 16 dB in 40–55 MHz. The measured data of 9 in. hybrid splitter is highly consistent with HFSS simulations. We found that the proposed 3 dB hybrid splitter can be tunable with amplitude-balanced, broadband response by changing dielectric insulators to keep the inner and outer conductors of coaxial line apart. The proposed 3 dB hybrid splitter can be utilized for load-resilient operations in a wide range of antenna load variations due to mode transitions or edge localized modes (ELMs) in fusion plasmas.

  15. Design and analysis of stepped impedance transformer from air filled waveguide to dielectric filled waveguide for high power microwave window applications

    Science.gov (United States)

    Sindam, Bashaiah; Sharma, P. K.; Raju, K. C. James

    2014-03-01

    This paper describes a design to achieve good microwave power transmission from an air filled rectangular waveguide to a narrow dielectric filled waveguide using a stepped impedance transformer. A novel material Ba(Zn1/3Ta2/3)O3 (BZT) having high dielectric constant and low dielectric loss has been proposed as a microwave window. The advantages of using such dielectric resonator materials for these applications is that they make the size reduction of such microwave components possible without unleashing microwave dissipation. A high density (more than 97%) and good microwave dielectric properties are obtained for BZT samples through the solid state reaction method. The obtained dielectric parameters are used to calculate the dimensions of the narrow dielectric window section in waveguide geometry and the resulting dielectric window structure is simulated using the IMST Empire simulator. The maximum power transmission is obtained by the simulated structure with a dielectric filled waveguide window of thickness 7.4 mm at 3.7 GHz with bandwidth of 780 MHz, which corresponds to an insertion loss (S21) magnitude of 0.008 dB, and the return loss (S11) obtained at the same frequency is -43 dB. The microwave dielectric properties of the material used as well as the simulated results for the BZT based window are studied and compared with those of a conventional window.

  16. High power accelerator-based boron neutron capture with a liquid lithium target and new applications to treatment of infectious diseases.

    Science.gov (United States)

    Halfon, S; Paul, M; Steinberg, D; Nagler, A; Arenshtam, A; Kijel, D; Polacheck, I; Srebnik, M

    2009-07-01

    A new conceptual design for an accelerator-based boron neutron capture therapy (ABNCT) facility based on the high-current low-energy proton beam driven by the linear accelerator at SARAF (Soreq Applied Research Accelerator Facility) incident on a windowless forced-flow liquid-lithium target, is described. The liquid-lithium target, currently in construction at Soreq NRC, will produce a neutron field suitable for the BNCT treatment of deep-seated tumor tissues, through the reaction (7)Li(p,n)(7)Be. The liquid-lithium target is designed to overcome the major problem of solid lithium targets, namely to sustain and dissipate the power deposited by the high-intensity proton beam. Together with diseases conventionally targeted by BNCT, we propose to study the application of our setup to a novel approach in treatment of diseases associated with bacterial infections and biofilms, e.g. inflammations on implants and prosthetic devices, cystic fibrosis, infectious kidney stones. Feasibility experiments evaluating the boron neutron capture effectiveness on bacteria annihilation are taking place at the Soreq nuclear reactor.

  17. High power accelerator-based boron neutron capture with a liquid lithium target and new applications to treatment of infectious diseases

    Energy Technology Data Exchange (ETDEWEB)

    Halfon, S. [Soreq NRC, Yavne 81800 (Israel); Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)], E-mail: halfon@phys.huji.ac.il; Paul, M. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Steinberg, D. [Biofilm Laboratory, Institute of Dental Sciences, Faculty of Dentistry, Hebrew University-Hadassah (Israel); Nagler, A.; Arenshtam, A.; Kijel, D. [Soreq NRC, Yavne 81800 (Israel); Polacheck, I. [Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center (Israel); Srebnik, M. [Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Hebrew University, Jerusalem 91120 (Israel)

    2009-07-15

    A new conceptual design for an accelerator-based boron neutron capture therapy (ABNCT) facility based on the high-current low-energy proton beam driven by the linear accelerator at SARAF (Soreq Applied Research Accelerator Facility) incident on a windowless forced-flow liquid-lithium target, is described. The liquid-lithium target, currently in construction at Soreq NRC, will produce a neutron field suitable for the BNCT treatment of deep-seated tumor tissues, through the reaction {sup 7}Li(p,n){sup 7}Be. The liquid-lithium target is designed to overcome the major problem of solid lithium targets, namely to sustain and dissipate the power deposited by the high-intensity proton beam. Together with diseases conventionally targeted by BNCT, we propose to study the application of our setup to a novel approach in treatment of diseases associated with bacterial infections and biofilms, e.g. inflammations on implants and prosthetic devices, cystic fibrosis, infectious kidney stones. Feasibility experiments evaluating the boron neutron capture effectiveness on bacteria annihilation are taking place at the Soreq nuclear reactor.

  18. Degradation mechanisms in high-power multi-mode InGaAs-AlGaAs strained quantum well lasers for high-reliability applications

    Science.gov (United States)

    Sin, Yongkun; Presser, Nathan; Brodie, Miles; Lingley, Zachary; Foran, Brendan; Moss, Steven C.

    2015-03-01

    Laser diode manufacturers perform accelerated multi-cell lifetests to estimate lifetimes of lasers using an empirical model. Since state-of-the-art laser diodes typically require a long period of latency before they degrade, significant amount of stress is applied to the lasers to generate failures in relatively short test durations. A drawback of this approach is the lack of mean-time-to-failure data under intermediate and low stress conditions, leading to uncertainty in model parameters (especially optical power and current exponent) and potential overestimation of lifetimes at usage conditions. This approach is a concern especially for satellite communication systems where high reliability is required of lasers for long-term duration in the space environment. A number of groups have studied reliability and degradation processes in GaAs-based lasers, but none of these studies have yielded a reliability model based on the physics of failure. The lack of such a model is also a concern for space applications where complete understanding of degradation mechanisms is necessary. Our present study addresses the aforementioned issues by performing long-term lifetests under low stress conditions followed by failure mode analysis (FMA) and physics of failure investigation. We performed low-stress lifetests on both MBE- and MOCVD-grown broad-area InGaAs- AlGaAs strained QW lasers under ACC (automatic current control) mode to study low-stress degradation mechanisms. Our lifetests have accumulated over 36,000 test hours and FMA is performed on failures using our angle polishing technique followed by EL. This technique allows us to identify failure types by observing dark line defects through a window introduced in backside metal contacts. We also investigated degradation mechanisms in MOCVD-grown broad-area InGaAs-AlGaAs strained QW lasers using various FMA techniques. Since it is a challenge to control defect densities during the growth of laser structures, we chose to

  19. High-power stirling-type pulse tube cooler for power engineering applications of high temperature superconductivity; Hochleistungspulsrohrkuehler vom Stirling-Typ fuer energietechnische Anwendungen der Hochtemperatursupraleitung

    Energy Technology Data Exchange (ETDEWEB)

    Dietrich, Marc

    2015-12-15

    For the cooling of high temperature superconducting 4 MVA machines (motors or generators), a single-stage Stirling-type pulse-tube cryocooler was built. The cooling power, which the cryocooler was aimed for, is 80 - 100 W at 30 K with an electrical input power of 10 kW (8 kW pV-power). The advantages of this cooler type compared to traditional cooling concepts are an increased reliability and long maintenance intervals. While single-stage Stirling-type pulse-tube cryocoolers for the temperature range of liquid nitrogen (77 K) are already commercially available, there exist currently no commercial systems for the temperature range near 30 K, which is the important range for applications of high-temperature superconductivity. The experimental setup consisted of a 10 kW linear compressor, type 2S297W, from CFIC Inc. which was used as the pressure wave generator. The compressor was operated by a Micromaster 440 frequency inverter from Siemens, which was controlled by a custom-made computer program. The cold head was made in inline configuration, in order to avoid deflection losses. During the first cool-downs tests a temperature inhomogeneity occurred in the regenerator at low temperature and high pV-power, which was attributed to a constant mass flow (circular dc-flow) within the regenerator. This firstly observed dc-flow, generates a net energy flow from the hot end to the cold end of the regenerator, which reduces the cooling capacity considerably and hence the minimum attainable temperature is severely increased. For the design and optimization of the cold-head, a cryocooler model was initially created using the commercial simulation software Sage, which did not include the regenerator inhomogeneity seen in the experiment. For the modeling of the observed streaming inhomogeneity caused by the dc-flow, the regenerator was replaced by two identical parallel regenerators with variable transverse thermal coupling. In the inhomogeneous case (without dc-flow) the

  20. High power lasers in manufacturing

    OpenAIRE

    Chatwin, Chris R

    2017-01-01

    Lecture covers a brief history of lasers and the important beam parameters for manufacturing applications. It introduces the main laser types that are appropriate for manufacturing: carbon dioxide lasers, Nd YAG, Diode and fibre lasers, excimer lasers. It then looks at applications to different products and also micro-engineering

  1. Advanced Output Coupling for High Power Gyrotrons

    Energy Technology Data Exchange (ETDEWEB)

    Read, Michael [Calabazas Creek Research, Inc., San Mateo, CA (United States); Ives, Robert Lawrence [Calabazas Creek Research, Inc., San Mateo, CA (United States); Marsden, David [Calabazas Creek Research, Inc., San Mateo, CA (United States); Collins, George [Calabazas Creek Research, Inc., San Mateo, CA (United States); Temkin, Richard [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Guss, William [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lohr, John [General Atomics, La Jolla, CA (United States); Neilson, Jeffrey [Lexam Research, Redwood City, CA (United States); Bui, Thuc [Calabazas Creek Research, Inc., San Mateo, CA (United States)

    2016-11-28

    The Phase II program developed an internal RF coupler that transforms the whispering gallery RF mode produced in gyrotron cavities to an HE11 waveguide mode propagating in corrugated waveguide. This power is extracted from the vacuum using a broadband, chemical vapor deposited (CVD) diamond, Brewster angle window capable of transmitting more than 1.5 MW CW of RF power over a broad range of frequencies. This coupling system eliminates the Mirror Optical Units now required to externally couple Gaussian output power into corrugated waveguide, significantly reducing system cost and increasing efficiency. The program simulated the performance using a broad range of advanced computer codes to optimize the design. Both a direct coupler and Brewster angle window were built and tested at low and high power. Test results confirmed the performance of both devices and demonstrated they are capable of achieving the required performance for scientific, defense, industrial, and medical applications.

  2. HIGH POWER APPLICATIONS OF ELECTROMAGNETIC DEVICES

    Directory of Open Access Journals (Sweden)

    VASILE DOBREF

    2016-06-01

    Full Text Available For the next generation, conventional weapon will touch the best performance limits and will became more and more what in what more an important part plans of improvement systems of weapon to the future. Physical laws that govern electromagnetic propulsion of guns, enabling them higher speeds than those of conventional arms projectiles. This is substantially benefit electromagnetic weapons - using electricity as energy for an lectromagnetic weapons.

  3. Electric propulsion device for high power applications

    Science.gov (United States)

    Roy, Subrata (Inventor)

    2009-01-01

    An electric propulsion device is disclosed having an anode and a cathode. The propulsion device includes a discharge annulus having the anode adjacent an end region thereof. At least one inlet aperture is adjacent the anode, the aperture(s) having propellant gas flow therethrough into the discharge annulus. The propellant gas has an ionization potential. Opposed, dielectric walls define the annulus, with at least one of the opposed dielectric walls having pores therein, the pores having cooling gas flow therethrough into the discharge annulus and substantially adjacent the opposed dielectric wall(s). The cooling gas has an ionization potential higher than the ionization energy of the propellant gas. The cooling gas is adapted to substantially prevent at least one of secondary electron emission and sputtering of the dielectric walls.

  4. High-power converters for space applications

    Science.gov (United States)

    Park, J. N.; Cooper, Randy

    1991-06-01

    Phase 1 was a concept definition effort to extend space-type dc/dc converter technology to the megawatt level with a weight of less than 0.1 kg/kW (220 lb./MW). Two system designs were evaluated in Phase 1. Each design operates from a 5 kV stacked fuel cell source and provides a voltage step-up to 100 kV at 10 A for charging capacitors (100 pps at a duty cycle of 17 min on, 17 min off). Both designs use an MCT-based, full-bridge inverter, gaseous hydrogen cooling, and crowbar fault protection. The GE-CRD system uses an advanced high-voltage transformer/rectifier filter is series with a resonant tank circuit, driven by an inverter operating at 20 to 50 kHz. Output voltage is controlled through frequency and phase shift control. Fast transient response and stability is ensured via optimal control. Super-resonant operation employing MCTs provides the advantages of lossless snubbing, no turn-on switching loss, use of medium-speed diodes, and intrinsic current limiting under load-fault conditions. Estimated weight of the GE-CRD system is 88 kg (1.5 cu ft.). Efficiency of 94.4 percent and total system loss is 55.711 kW operating at 1 MW load power. The Maxwell system is based on a resonance transformer approach using a cascade of five LC resonant sections at 100 kHz. The 5 kV bus is converted to a square wave, stepped-up to a 100 kV sine wave by the LC sections, rectified, and filtered. Output voltage is controlled with a special series regulator circuit. Estimated weight of the Maxwell system is 83.8 kg (4.0 cu ft.). Efficiency is 87.2 percent and total system loss is 146.411 kW operating at 1 MW load power.

  5. Inkjet printing of novel wideband and high gain antennas on low-cost paper substrate

    KAUST Repository

    Cook, Benjamin Stassen

    2012-09-01

    A complete characterization of the inkjet printing process using metallic nanoparticle inks on a paper substrate for microwave frequencies up to 12.5 GHz as well as its application to low-cost, high gain and wideband antenna design are demonstrated in this work. Laser and heat sintering of metallic nanoparticles are compared on paper substrate for the first time which demonstrate immense cost and time benefits of laser sintering. The antennas fabricated using the characterized process include a Vivaldi for the UWB band which exhibits a significantly higher gain of up to 8 dBi as compared to the currently published inkjet printed antennas, and a novel slow-wave log periodic dipole array which employs a new miniaturization technique to show 20% width reduction. © 1963-2012 IEEE.

  6. High Gain (43 dB) High Power (40W), Highly Efficient Multipass Amplifier at 995 nm in Yb:LiYFf4

    Science.gov (United States)

    2016-12-22

    pulse energy fluctuations . Also, they require high‐speed electro‐optic switching. Angular multi‐ passing [1–15] has been used less frequently...effects, as the quantum defect is small and the thermo‐optic properties are excellent at cryogenic temperature. We estimate that the beam quality...Yb:YAG lifetime,” IEEE J.  Quantum  Electron. 45, 993‐1005 (2009)  10. D. N. Papadopoulos, A. Pellegrina, L. P. Ramirez, P. Georges, and F.  Druon

  7. High gain (43 dB), high power (40 W), highly efficient multipass amplifier at 995 nm inYb:LiYF4

    Science.gov (United States)

    2017-04-15

    combination of large-signal gain (43 dB), efficiency (>50% optical), average output power (40 W) and a near-diffraction-limited output beam. Index...communications and lidar, and high efficiency for such amplifiers is desired as well, particularly in high average power laser systems. Optical fiber...amplifiers work well for cw or high-duty cycle waveforms, but can be problematic as the power (both peak and average) increases because of optical

  8. High power ultrashort pulse lasers

    Energy Technology Data Exchange (ETDEWEB)

    Perry, M.D.

    1994-10-07

    Small scale terawatt and soon even petawatt (1000 terawatt) class laser systems are made possible by application of the chirped-pulse amplification technique to solid-state lasers combined with the availability of broad bandwidth materials. These lasers make possible a new class of high gradient accelerators based on the large electric fields associated with intense laser-plasma interactions or from the intense laser field directly. Here, we concentrate on the laser technology to produce these intense pulses. Application of the smallest of these systems to the production of high brightness electron sources is also introduced.

  9. Atmospheric propagation and combining of high-power lasers.

    Science.gov (United States)

    Nelson, W; Sprangle, P; Davis, C C

    2016-03-01

    In this paper, we analyze beam combining and atmospheric propagation of high-power lasers for directed-energy (DE) applications. The large linewidths inherent in high-power fiber and slab lasers cause random phase and intensity fluctuations that occur on subnanosecond time scales. Coherently combining these high-power lasers would involve instruments capable of precise phase control and operation at rates greater than ∼10  GHz. To the best of our knowledge, this technology does not currently exist. This presents a challenging problem when attempting to phase lock high-power lasers that is not encountered when phase locking low-power lasers, for example, at milliwatt power levels. Regardless, we demonstrate that even if instruments are developed that can precisely control the phase of high-power lasers, coherent combining is problematic for DE applications. The dephasing effects of atmospheric turbulence typically encountered in DE applications will degrade the coherent properties of the beam before it reaches the target. Through simulations, we find that coherent beam combining in moderate turbulence and over multikilometer propagation distances has little advantage over incoherent combining. Additionally, in cases of strong turbulence and multikilometer propagation ranges, we find nearly indistinguishable intensity profiles and virtually no difference in the energy on the target between coherently and incoherently combined laser beams. Consequently, we find that coherent beam combining at the transmitter plane is ineffective under typical atmospheric conditions.

  10. Design and analysis of 30 nm T-gate InAlN/GaN HEMT with AlGaN back-barrier for high power microwave applications

    Science.gov (United States)

    Murugapandiyan, P.; Ravimaran, S.; William, J.; Meenakshi Sundaram, K.

    2017-11-01

    In this article, we present the DC and microwave characteristics of a novel 30 nm T-gate InAlN/AlN/GaN HEMT with AlGaN back-barrier. The device structure is simulated by using Synopsys Sentaurus TCAD Drift-Diffusion transport model at room temperature. The device features are heavily doped (n++ GaN) source/drain regions with Si3N4 passivated device surface for reducing the contact resistances and gate capacitances of the device, which uplift the microwave characteristics of the HEMTs. 30 nm gate length D-mode (E-mode) HEMT exhibited a peak drain current density Idmax of 2.3 (2.42) A/mm, transconductance gm of 1.24(1.65) S/mm, current gain cut-off frequency ft of 262 (246) GHz, power gain cut-off frequency fmax of 246(290) GHz and the three terminal off-state breakdown voltage VBR of 40(38) V. The preeminent microwave characteristics with the higher breakdown voltage of the proposed GaN-based HEMT are the expected to be the most optimistic applicant for future high power millimeter wave applications.

  11. Electronic DC transformer with high power density

    NARCIS (Netherlands)

    Pavlovský, M.

    2006-01-01

    This thesis is concerned with the possibilities of increasing the power density of high-power dc-dc converters with galvanic isolation. Three cornerstones for reaching high power densities are identified as: size reduction of passive components, reduction of losses particularly in active components

  12. High power laser perforating tools and systems

    Science.gov (United States)

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2014-04-22

    ystems devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser perforation of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to perforate such boreholes.

  13. High Power Electron Accelerator Prototype

    CERN Document Server

    Tkachenko, Vadim; Cheskidov, Vladimir; Korobeynikov, G I; Kuznetsov, Gennady I; Lukin, A N; Makarov, Ivan; Ostreiko, Gennady; Panfilov, Alexander; Sidorov, Alexey; Tarnetsky, Vladimir V; Tiunov, Michael A

    2005-01-01

    In recent time the new powerful industrial electron accelerators appear on market. It caused the increased interest to radiation technologies using high energy X-rays due to their high penetration ability. However, because of low efficiency of X-ray conversion for electrons with energy below 5 MeV, the intensity of X-rays required for some industrial applications can be achieved only when the beam power exceeds 300 kW. The report describes a project of industrial electron accelerator ILU-12 for electron energy up to 5 MeV and beam power up to 300 kW specially designed for use in industrial applications. On the first stage of work we plan to use the existing generator designed for ILU-8 accelerator. It is realized on the GI-50A triode and provides the pulse power up to 1.5-2 MW and up to 20-30 kW of average power. In the report the basic concepts and a condition of the project for today are reflected.

  14. High power regenerative laser amplifier

    Science.gov (United States)

    Miller, John L.; Hackel, Lloyd A.; Dane, Clifford B.; Zapata, Luis E.

    1994-01-01

    A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse.

  15. Energy Efficient and Compact RF High-Power Amplifiers

    NARCIS (Netherlands)

    Calvillo Cortés, D.A.

    2014-01-01

    The main objectives of this thesis are to improve the energy efficiency and physical form-factor of high-power amplifiers in base station applications. As such, the focus of this dissertation is placed on the outphasing amplifier concept, which can offer high-efficiency, good linearity and excellent

  16. Heatsink Design of High Power Converter

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chan Ki [Chungang University (Korea)

    1999-04-01

    Various ways of designing heat sink are available for commercial high power converters and among them, the method of air cooling is the most popular and practical method than any other ones. In this paper, a practical method of cooling high power converter, which includes a method of reducing noise and vibration caused by the fan and a method of estimating the gap and contact resistances existing between the thyristor and heat sink, is presented. Finally, the heat transfer analysis and implementation methods of heat sink for high power converter is presented. (author). 14 refs., 11 figs., 3 tabs.

  17. Substrate effects in high gain, low operating voltage SnSe2 photoconductor

    Science.gov (United States)

    Krishna, Murali; Kallatt, Sangeeth; Majumdar, Kausik

    2018-01-01

    High gain photoconductive devices find wide spread applications in low intensity light detection. Ultra-thin layered materials have recently drawn a lot of attention from researchers in this regard. However, in general, a large operating voltage is required to obtain large responsivity in these devices. In addition, the characteristics are often confounded by substrate induced trap effects. Here we report multi-layer SnSe2 based photoconductive devices using two different structures: (1) SiO2 substrate supported inter-digitated electrode (IDE), and (2) suspended channel. The IDE device exhibits a responsivity of ≈ {10}3 A W‑1 and ≈ 8.66× {10}4 A W‑1 at operating voltages of 1 mV and 100 mV, respectively—a superior low voltage performance over existing literature on planar 2D structures. However, the responsivity reduces by more than two orders of magnitude, while the transient response improves for the suspended device—providing insights into the critical role played by the channel-substrate interface in the gain mechanism. The results, on one hand, are promising for highly sensitive photoconductive applications consuming ultra-low power, and on the other hand, show a generic methodology that could be applied to other layered material based photoconductive devices as well for extracting the intrinsic behavior.

  18. High Gain and High Directive of Antenna Arrays Utilizing Dielectric Layer on Bismuth Titanate Ceramics

    Directory of Open Access Journals (Sweden)

    F. H. Wee

    2012-01-01

    Full Text Available A high gain and high directive microstrip patch array antenna formed from dielectric layer stacked on bismuth titanate (BiT ceramics have been investigated, fabricated, and measured. The antennas are designed and constructed with a combination of two-, four-, and six-BiT elements in an array form application on microwave substrate. For gain and directivity enhancement, a layer of dielectric was stacked on the BiT antenna array. We measured the gain and directivity of BiT array antennas with and without the dielectric layer and found that the gain of BiT array antenna with the dielectric layer was enhanced by about 1.4 dBi of directivity and 1.3 dB of gain over the one without the dielectric layer at 2.3 GHz. The impedance bandwidth of the BiT array antenna both with and without the dielectric layer is about 500 MHz and 350 MHz, respectively, which is suitable for the application of the WiMAX 2.3 GHz system. The utilization of BiT ceramics that covers about 90% of antenna led to high radiation efficiency, and small-size antennas were produced. In order to validate the proposed design, theoretical and measured results are provided and discussed.

  19. Fibrous zinc anodes for high power batteries

    Science.gov (United States)

    Zhang, X. Gregory

    This paper introduces newly developed solid zinc anodes using fibrous material for high power applications in alkaline and large size zinc-air battery systems. The improved performance of the anodes in these two battery systems is demonstrated. The possibilities for control of electrode porosity and for anode/battery design using fibrous materials are discussed in light of experimental data. Because of its mechanical integrity and connectivity, the fibrous solid anode has good electrical conductivity, mechanical stability, and design flexibility for controlling mass distribution, porosity and effective surface area. Experimental data indicated that alkaline cells made of such anodes can have a larger capacity at high discharging currents than commercially available cells. It showed even greater improvement over commercial cells with a non-conventional cell design. Large capacity anodes for a zinc-air battery have also been made and have shown excellent material utilization at various discharge rates. The zinc-air battery was used to power an electric bicycle and demonstrated good results.

  20. Piezoelectric Transformers for a High Power Module

    National Research Council Canada - National Science Library

    Ezaki, T

    2003-01-01

    .... Here, in order to obtain compact and high-power AC-DC adaptors, we explored suitable designs for a multi-layered piezoelectric transformer, by taking into account the effect of the mechanical quality...

  1. High Power Helicon Plasma Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed work seeks to develop and optimize an electrode-less plasma propulsion system that is based on a high power helicon (HPH) that is being developed...

  2. High Power Helicon Plasma Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A new thruster has been conceived and tested that is based on a high power helicon (HPH) plasma wave. In this new method of propulsion, an antenna generates and...

  3. High Power Fiber Laser Test Bed

    Data.gov (United States)

    Federal Laboratory Consortium — This facility, unique within DoD, power-combines numerous cutting-edge fiber-coupled laser diode modules (FCLDM) to integrate pumping of high power rare earth-doped...

  4. High Power Performance of Rod Fiber Amplifiers

    DEFF Research Database (Denmark)

    Johansen, Mette Marie; Michieletto, Mattia; Kristensen, Torben

    2015-01-01

    An improved version of the DMF rod fiber is tested in a high power setup delivering 360W of stable signal power. Multiple testing degrades the fiber and transverse modal instability threshold from >360W to ~290W.......An improved version of the DMF rod fiber is tested in a high power setup delivering 360W of stable signal power. Multiple testing degrades the fiber and transverse modal instability threshold from >360W to ~290W....

  5. Switching power converters medium and high power

    CERN Document Server

    Neacsu, Dorin O

    2013-01-01

    An examination of all of the multidisciplinary aspects of medium- and high-power converter systems, including basic power electronics, digital control and hardware, sensors, analog preprocessing of signals, protection devices and fault management, and pulse-width-modulation (PWM) algorithms, Switching Power Converters: Medium and High Power, Second Edition discusses the actual use of industrial technology and its related subassemblies and components, covering facets of implementation otherwise overlooked by theoretical textbooks. The updated Second Edition contains many new figures, as well as

  6. Epitaxial Gd2O3 on GaN and AlGaN: a potential candidate for metal oxide semiconductor based transistors on Si for high power application

    Science.gov (United States)

    Ghosh, Kankat; Das, S.; Khiangte, K. R.; Choudhury, N.; Laha, Apurba

    2017-11-01

    We report structural and electrical properties of hexagonal Gd2O3 grown epitaxially on GaN/Si (1 1 1) and AlGaN/GaN/Si(1 1 1) virtual substrates. GaN and AlGaN/GaN heterostructures were grown on Si(1 1 1) substrates by plasma assisted molecular beam epitaxy (PA-MBE), whereas the Gd2O3 layer was grown by the pulsed laser ablation (PLA) technique. Initial structural characterizations show that Gd2O3 grown on III-nitride layers by PLA, exhibit a hexagonal structure with an epitaxial relationship as {{≤ft[ 0 0 0 1 \\right]}G{{d2}{{O}3}}}||{{≤ft[ 0 0 0 1 \\right]}GaN} and {{≤ft[ 1 \\bar{1} 0 0 \\right]}G{{d2}{{O}3}}}||{{≤ft[ 1 \\bar{1} 0 0 \\right]}GaN} . X-ray photoelectron measurements of the valence bands revealed that Gd2O3 exhibits band offsets of 0.97 eV and 0.4 eV, for GaN and Al0.3Ga0.7N, respectively. Electrical measurements such as capacitance–voltage and leakage current characteristics further confirm that epi-Gd2O3 on III-nitrides could be a potential candidate for future metal-oxide-semiconductor (MOS)-based transistors also for high power applications in radio frequency range.

  7. Interface engineered Li4Ti5O12-TiO2 dual-phase nanoparticles and CNT additive for supercapacitor-like high power Li-ion battery applications.

    Science.gov (United States)

    Gangaja, Binitha; Nair, Shantikumar; Santhanagopalan, Dhamodaran

    2017-12-19

    Single-pot synthesis of dual-phase spinel-Li4Ti5O12 and anatase-TiO2 (LTO-TiO2) nanoparticles over the entire phase-fractions ranging from pure LTO to pure TiO2is conducted. Process over the complete range enabled the identification of a unique weight ratio of 85:15 (LTO:TiO2) that provide the best combination of capacity, rate capability and cycling stability. We show that for this composition the dual-phase nanoparticles have the interfacial orientation predominantly of (111)LTO(004)TiO2 while it is (111)LTO(101)TiO2 for other compositions. This study therefore shows that the dual-phase interfaced with these specific orientations give the best performance. Synergistic combination of dual-phase nanoparticles with multi-wall carbon nanotubes improves the performance further. This results in an electrode with supercapacitor-like rate capability delivering high discharge capacities of 174, 127, 119, 110, 101 and 91 mAh/g at 2000, 6000, 12000, 18000, 24000 and 30000 mA/g specific currents respectively. Discharge capacity of 174 mAh/g at 2000 mA/g specific current with only 0.005% capacity loss per cycle over 3000 cycles is demonstrated. At current densities 6000, 12000 and 24000 mA/g stable cycling is obtained for 1500 cycles. Present work enables nano-engineered interfaces in LTO-TiO2 dual-phase nanoparticles with electrochemical performances better than its individual components; which has potential for high power Li-ion battery applications. © 2017 IOP Publishing Ltd.

  8. Very High Gain and Low Noise Near Infrared Single Photon Counting Detectors and Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Amplification Technologies Inc ("ATI") proposes to develop the enabling material and device technology for the design of ultra low noise, high gain and low...

  9. InGaAs/AlGaAsSb avalanche photodiode with high gain-bandwidth product.

    Science.gov (United States)

    Xie, Shiyu; Zhou, Xinxin; Zhang, Shiyong; Thomson, David J; Chen, Xia; Reed, Graham T; Ng, Jo Shien; Tan, Chee Hing

    2016-10-17

    Increasing reliance on the Internet places greater and greater demands for high-speed optical communication systems. Increasing their data transfer rate allows more data to be transferred over existing links. With optical receivers being essential to all optical links, bandwidth performance of key components in receivers, such as avalanche photodiodes (APDs), must be improved. The APDs rely on In0.53Ga0.47As (grown lattice-matched to InP substrates) to efficiently absorb and detect the optical signals with 1310 or 1550 nm wavelength, the optimal wavelengths of operation for these optical links. Thus developing InP-compatible APDs with high gain-bandwidth product (GBP) is important to the overall effort of increasing optical links' data transfer rate. Here we demonstrate a novel InGaAs/AlGaAsSb APD, grown on an InP substrate, with a GBP of 424 GHz, the highest value reported for InP-compatible APDs, which is clearly applicable to future optical communication systems at or above 10 Gb/s. The data reported in this article are available from the figshare digital repository (https://dx.doi.org/10.15131/shef. 3827460.v1).

  10. Millimeter Wave Fabry-Perot Resonator Antenna Fed by CPW with High Gain and Broadband

    Directory of Open Access Journals (Sweden)

    Xue-Xia Yang

    2016-01-01

    Full Text Available A novel millimeter wave coplanar waveguide (CPW fed Fabry-Perot (F-P antenna with high gain, broad bandwidth, and low profile is reported. The partially reflective surface (PRS and the ground form the F-P resonator cavity, which is filled with the same dielectric substrate. A dual rhombic slot loop on the ground acts as the primary feeding antenna, which is fed by the CPW and has broad bandwidth. In order to improve the antenna gain, metal vias are inserted surrounding the F-P cavity. A CPW-to-microstrip transition is designed to measure the performances of the antenna and extend the applications. The measured impedance bandwidth of S11 less than −10 dB is from 34 to 37.7 GHz (10.5%, and the gain is 15.4 dBi at the center frequency of 35 GHz with a 3 dB gain bandwidth of 7.1%. This performance of the antenna shows a tradeoff among gain, bandwidth, and profile.

  11. Transportation-cyber-physical-systems-oriented engine cylinder pressure estimation using high gain observer

    Science.gov (United States)

    Li, Yong-Fu; Xiao-Pei, Kou; Zheng, Tai-Xiong; Li, Yin-Guo

    2015-05-01

    In transportation cyber-physical-systems (T-CPS), vehicle-to-vehicle (V2V) communications play an important role in the coordination between individual vehicles as well as between vehicles and the roadside infrastructures, and engine cylinder pressure is significant for engine diagnosis on-line and torque control within the information exchange process under V2V communications. However, the parametric uncertainties caused from measurement noise in T-CPS lead to the dynamic performance deterioration of the engine cylinder pressure estimation. Considering the high accuracy requirement under V2V communications, a high gain observer based on the engine dynamic model is designed to improve the accuracy of pressure estimation. Then, the analyses about convergence, converge speed and stability of the corresponding error model are conducted using the Laplace and Lyapunov method. Finally, results from combination of Simulink with GT-Power based numerical experiments and comparisons demonstrate the effectiveness of the proposed approach with respect to robustness and accuracy. Project supported by the National Natural Science Foundation of China (Grant No. 61304197), the Scientific and Technological Talents of Chongqing, China (Grant No. cstc2014kjrc-qnrc30002), the Key Project of Application and Development of Chongqing, China (Grant No. cstc2014yykfB40001), the Natural Science Funds of Chongqing, China (Grant No. cstc2014jcyjA60003), and the Doctoral Start-up Funds of Chongqing University of Posts and Telecommunications, China (Grant No. A2012-26).

  12. Stable Graphene-Two-Dimensional Multiphase Perovskite Heterostructure Phototransistors with High Gain.

    Science.gov (United States)

    Shao, Yuchuan; Liu, Ye; Chen, Xiaolong; Chen, Chen; Sarpkaya, Ibrahim; Chen, Zhaolai; Fang, Yanjun; Kong, Jaemin; Watanabe, Kenji; Taniguchi, Takashi; Taylor, André; Huang, Jinsong; Xia, Fengnian

    2017-12-13

    Recently, two-dimensional (2D) organic-inorganic perovskites emerged as an alternative material for their three-dimensional (3D) counterparts in photovoltaic applications with improved moisture resistance. Here, we report a stable, high-gain phototransistor consisting of a monolayer graphene on hexagonal boron nitride (hBN) covered by a 2D multiphase perovskite heterostructure, which was realized using a newly developed two-step ligand exchange method. In this phototransistor, the multiple phases with varying bandgap in 2D perovskite thin films are aligned for the efficient electron-hole pair separation, leading to a high responsivity of ∼105 A W-1 at 532 nm. Moreover, the designed phase alignment method aggregates more hydrophobic butylammonium cations close to the upper surface of the 2D perovskite thin film, preventing the permeation of moisture and enhancing the device stability dramatically. In addition, faster photoresponse and smaller 1/f noise observed in the 2D perovskite phototransistors indicate a smaller density of deep hole traps in the 2D perovskite thin film compared with their 3D counterparts. These desirable properties not only improve the performance of the phototransistor, but also provide a new direction for the future enhancement of the efficiency of 2D perovskite photovoltaics.

  13. Facet engineering of high power single emitters

    Science.gov (United States)

    Yanson, Dan; Levi, Moshe; Shamay, Moshe; Tesler, Renana; Rappaport, Noam; Don, Yaroslav; Karni, Yoram; Schnitzer, Itzhak; Sicron, Noam; Shusterman, Sergey

    2011-03-01

    The ever increasing demand for high-power, high-reliability operation of single emitters at 9xx nm wavelengths requires the development of laser diodes with improved facet regions immune to both catastrophic and wear-out failure modes. In our study, we have evaluated several laser facet definition technologies in application to 90 micron aperture single emitters in asymmetric design (In)GaAs/AlGaAs based material emitting at 915, 925 and 980nm. A common epitaxy and emitter design makes for a straightforward comparison of the facet technologies investigated. Our study corroborates a clear trend of increasing difficulty in obtaining reliable laser operation from 980nm down to 915nm. At 980nm, one can employ dielectric facet passivation with a pre-clean cycle delivering a device lifetime in excess of 3,000 hours at increasing current steps. At 925nm, quantum-well intermixing can be used to define non-absorbing mirrors giving good device reliability, albeit with a large efficiency penalty. Vacuum cleaved emitters have delivered excellent reliability at 915nm, and can be expected to perform just as well at 925 and 980nm. Epitaxial regrowth of laser facets is under development and has yet to demonstrate an appreciable reliability improvement. Only a weak correlation between start-of-life catastrophic optical mirror damage (COMD) levels and reliability was established. The optimized facet design has delivered maximum powers in excess of 19 MW/sq.cm (rollover limited) and product-grade 980nm single emitters with a slope efficiency of >1 W/A and a peak efficiency of >60%. The devices have accumulated over 1,500 hours of CW operation at 11W. A fiber-coupled device emits 10W ex-fiber with 47% efficiency.

  14. Germanate Glass Fiber Lasers for High Power

    Science.gov (United States)

    2016-01-04

    AFRL-AFOSR-JP-TR-2016-0020 Germanate glass fiber lasers for high power David Lancaster THE UNIVERSITY OF ADELAIDE Final Report 01/04/2016...COVERED (From - To) 01-07-2014 to 30-06-2015 4. TITLE AND SUBTITLE Germanate glass fiber lasers for high power 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER...germanate based glasses with a specific focus on glass stability during thermal-cycling which is representative of the steps required to fabricate a doped

  15. Resonance tracking and vibration stablilization for high power ultrasonic transducers.

    Science.gov (United States)

    Kuang, Y; Jin, Y; Cochran, S; Huang, Z

    2014-01-01

    Resonant frequency shift and electrical impedance variation are common phenomena in the application of high power ultrasonic transducers, e.g. in focused ultrasound surgery and in cutting. They result in low power efficiency and unstable vibration amplitude. To solve this problem, a driving and measurement system has been developed to track the resonance of high power transducers and to stabilise their vibration velocity. This has the ability to monitor the operating and performance parameters of the ultrasonic transducers in real time. The configuration of the system, with its control algorithm implemented in LabVIEW (National Instruments, Newbury, UK), ensures flexibility to suit different transducers and load conditions. In addition, with different programs, it can be utilised as a high power impedance analyser or an instantaneous electrical power measurement system for frequencies in the MHz range. The effectiveness of this system has been demonstrated in detailed studies. With it, high transducer performance at high power can be achieved and monitored in real time. Copyright © 2013. Published by Elsevier B.V.

  16. Development of a high power femtosecond laser

    CSIR Research Space (South Africa)

    Neethling, PH

    2010-10-01

    Full Text Available The Laser Research Institute and the CSIR National Laser Centre are developing a high power femtosecond laser system in a joint project with a phased approach. The laser system consists of an fs oscillator and a regenerative amplifier. An OPCPA...

  17. Automated System Tests High-Power MOSFET's

    Science.gov (United States)

    Huston, Steven W.; Wendt, Isabel O.

    1994-01-01

    Computer-controlled system tests metal-oxide/semiconductor field-effect transistors (MOSFET's) at high voltages and currents. Measures seven parameters characterizing performance of MOSFET, with view toward obtaining early indication MOSFET defective. Use of test system prior to installation of power MOSFET in high-power circuit saves time and money.

  18. Driver Circuit For High-Power MOSFET's

    Science.gov (United States)

    Letzer, Kevin A.

    1991-01-01

    Driver circuit generates rapid-voltage-transition pulses needed to switch high-power metal oxide/semiconductor field-effect transistor (MOSFET) modules rapidly between full "on" and full "off". Rapid switching reduces time of overlap between appreciable current through and appreciable voltage across such modules, thereby increasing power efficiency.

  19. High-power thulium lasers on a silicon photonics platform.

    Science.gov (United States)

    Li, Nanxi; Purnawirman, P; Su, Zhan; Salih Magden, E; Callahan, Patrick T; Shtyrkova, Katia; Xin, Ming; Ruocco, Alfonso; Baiocco, Christopher; Ippen, Erich P; Kärtner, Franz X; Bradley, Jonathan D B; Vermeulen, Diedrik; Watts, Michael R

    2017-03-15

    Mid-infrared laser sources are of great interest for various applications, including light detection and ranging, spectroscopy, communication, trace-gas detection, and medical sensing. Silicon photonics is a promising platform that enables these applications to be integrated on a single chip with low cost and compact size. Silicon-based high-power lasers have been demonstrated at 1.55 μm wavelength, while in the 2 μm region, to the best of our knowledge, high-power, high-efficiency, and monolithic light sources have been minimally investigated. In this Letter, we report on high-power CMOS-compatible thulium-doped distributed feedback and distributed Bragg reflector lasers with single-mode output powers up to 267 and 387 mW, and slope efficiencies of 14% and 23%, respectively. More than 70 dB side-mode suppression ratio is achieved for both lasers. This work extends the applicability of silicon photonic microsystems in the 2 μm region.

  20. Femtosecond Ti:sapphire cryogenic amplifier with high gain and MHz repetition rate

    DEFF Research Database (Denmark)

    Dantan, Aurelien Romain; Laurat, Julien; Ourjoumtsev, Alexei

    2007-01-01

    We demonstrate high gain amplification of 160-femtosecond pulses in a compact double-pass cryogenic Ti:sapphire amplifier. The setup involves a negative GVD mirrors recompression stage, and operates with a repetition rate between 0.2 and 4 MHz with a continuous pump laser. Amplification factors...

  1. Protection Related to High-power Targets

    CERN Document Server

    Plum, M.A.

    2016-01-01

    Target protection is an important part of machine protection. The beam power in high-intensity accelerators is high enough that a single wayward pulse can cause serious damage. Today's high-power targets operate at the limit of available technology, and are designed for a very narrow range of beam parameters. If the beam pulse is too far off centre, or if the beam size is not correct, or if the beam density is too high, the target can be seriously damaged. We will start with a brief introduction to high-power targets and then move to a discussion of what can go wrong, and what are the risks. Next we will discuss how to control the beam-related risk, followed by examples from a few different accelerator facilities. We will finish with a detailed example of the Oak Ridge Spallation Neutron Source target tune up and target protection.

  2. Graphene supercapacitor with both high power and energy density

    Science.gov (United States)

    Yang, Hao; Kannappan, Santhakumar; Pandian, Amaresh S.; Jang, Jae-Hyung; Lee, Yun Sung; Lu, Wu

    2017-11-01

    Supercapacitors, based on fast ion transportation, are specialized to provide high power, long stability, and efficient energy storage using highly porous electrode materials. However, their low energy density excludes them from many potential applications that require both high energy density and high power density performances. Using a scalable nanoporous graphene synthesis method involving an annealing process in hydrogen, here we show supercapacitors with highly porous graphene electrodes capable of achieving not only a high power density of 41 kW kg-1 and a Coulombic efficiency of 97.5%, but also a high energy density of 148.75 Wh kg-1. A high specific gravimetric and volumetric capacitance (306.03 F g-1 and 64.27 F cm-3) are demonstrated. The devices can retain almost 100% capacitance after 7000 charging/discharging cycles at a current density of 8 A g-1. The superior performance of supercapacitors is attributed to their ideal pore size, pore uniformity, and good ion accessibility of the synthesized graphene.

  3. High-power converters and AC drives

    CERN Document Server

    Wu, Bin

    2017-01-01

    This new edition reflects the recent technological advancements in the MV drive industry, such as advanced multilevel converters and drive configurations. It includes three new chapters, Control of Synchronous Motor Drives, Transformerless MV Drives, and Matrix Converter Fed Drives. In addition, there are extensively revised chapters on Multilevel Voltage Source Inverters and Voltage Source Inverter-Fed Drives. This book includes a systematic analysis on a variety of high-power multilevel converters, illustrates important concepts with simulations and experiments, introduces various megawatt drives produced by world leading drive manufacturers, and addresses practical problems and their mitigations methods.

  4. High Power Argon, Nitrogen Plasma Torches

    Science.gov (United States)

    Hakki, A.; Kashapov, N.; Sadikov, K.

    2017-11-01

    The paper describes a high power supply for Argon and Nitrogen plasma torches. A high frequency was used in order to drive the pulse width modulation circuit. The average output current consumption (AOCC) was modified from 20A up to 80A by increasing the pulse width from 2μsec up to 3μsec for Argon gas plasma torches. The (AOCC) was reduced from 70A down to 25A by increasing the pulse width from 6μsec up to 8μsec in the case of Nitrogen gas plasma torches.

  5. Inkjet Printing of Paper-Based Wideband and High Gain Antennas

    KAUST Repository

    Cook, Benjamin

    2011-12-07

    This thesis represents a major contribution to wideband and high gain inkjet-printed antennas on paper. This work includes the complete characterization of the inkjet printing process for passive microwave devices on paper substrate as well as several ultra-wideband and high gain antenna designs. The characterization work includes the electrical characterization of the permittivity and loss tangent for paper substrate through 10 GHz, ink conductivity data for variable sintering conditions, and minimum feature sizes obtainable by today’s current inkjet processes for metallic nanoparticles. For the first time ever, inkjet-printed antennas are demonstrated that operate over the entire UWB band and demonstrate gains up to 8dB. This work also presents the first fractal-based inkjet-printed antennas with enhanced bandwidth and reduced production costs, and a novel slow wave log periodic dipole array which shows minimizations of 20% in width over conventional log periodic antennas.

  6. Shock ignition: a new approach to high gain inertial confinement fusion on the national ignition facility.

    Science.gov (United States)

    Perkins, L J; Betti, R; LaFortune, K N; Williams, W H

    2009-07-24

    Shock ignition, an alternative concept for igniting thermonuclear fuel, is explored as a new approach to high gain, inertial confinement fusion targets for the National Ignition Facility (NIF). Results indicate thermonuclear yields of approximately 120-250 MJ may be possible with laser drive energies of 1-1.6 MJ, while gains of approximately 50 may still be achievable at only approximately 0.2 MJ drive energy. The scaling of NIF energy gain with laser energy is found to be G approximately 126E (MJ);{0.510}. This offers the potential for high-gain targets that may lead to smaller, more economic fusion power reactors and a cheaper fusion energy development path.

  7. High Gain Patch Antenna with Composite Right-Left Handed Structure and Dendritic Cell Metamaterials

    Science.gov (United States)

    Liu, Yahong; Zhao, Xiaopeng

    2010-04-01

    We present a novel high-gain patch antenna utilizing composite right-left handed (CRLH) structure and dendritic cell metamaterials. The proposed CRLH antenna, composed of modified Sievenpiper mushroom unit-cells, is based on the positive first-order resonance mode for high gain. In addition, the dendritic cell metamaterials are used to surround the proposed antenna to further increase the antenna directivity and gain due to suppressing the surface waves. The experimental results show that the gain and the directivity of the proposed antenna with CRLH and dendritic cells can be improved by 3.88 dB and 8.82, respectively, in comparison with a conventional patch antenna. Moreover, a 10-dB bandwidth with 9.55% is achieved. The measured results are in good agreement with the simulated ones.

  8. Improvement on a 2 × 2 Elements High-Gain Circularly Polarized Antenna Array

    Directory of Open Access Journals (Sweden)

    C. Liu

    2015-01-01

    Full Text Available A novel antipodal Vivaldi antenna with tapering serrated structure at the edges is proposed. Compared with traditional Vivaldi antennas without serrated structure, the gain of the designed antenna is significantly improved in the desired frequency band (4.5–7.5 GHz. In addition, a 2 × 2 Vivaldi antenna array with an orthorhombic structure is designed and fabricated to achieve a circular polarization (CP characteristic. With this configuration, the 3 dB axial ratio bandwidth of the array reaches about 42% with respect to the center frequency of 6 GHz and a high gain is achieved as well. The novel Vivaldi antenna and CP antenna array both have ultrawide band (UWB and high-gain characteristics, which may be applied to the field of commercial communication, remote sensing, and so forth.

  9. Longitudinal Coherence Preservation and Chirp Evolution in a High Gain Laser Seeded Free Electron Laser Amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, J.B.; /BNL, NSLS; Wu, Juhao; /SLAC; Wang, X.J.; Watanabe, T.; /BNL, NSLS

    2006-06-07

    In this letter we examine the start-up of a high gain free electron laser in which a frequency-chirped coherent seed laser pulse interacts with a relativistic electron beam. A Green function formalism is used to evaluate the initial value problem. We have fully characterized the startup and evolution through the exponential growth regime. We obtain explicit expressions for the pulse duration, bandwidth and chirp of the amplified light and show that the FEL light remains fully longitudinally coherent.

  10. Optimized VCSELs for high-power arrays

    Science.gov (United States)

    Moench, Holger; Kolb, Johanna S.; Engelhardt, Andreas P.; Gerlach, Philipp; Jaeger, Roland; Pollmann-Retsch, Jens; Weichmann, Ulrich; Witzigmann, Bernd

    2014-02-01

    High-power VCSEL systems with multi kilowatt output power require a good electro-optical efficiency at the point of operation i.e. at elevated temperature. The large number of optimization parameters can be structured in a way that separates system and assembly considerations from the minimization of electrical and optical losses in the epitaxially grown structure. Temperature dependent functions for gain parameters, internal losses and injection efficiency are derived from a fit to experimental data. The empirical description takes into account diameter dependent effects like current spreading or temperature dependent ones like voltage drops over hetero-interfaces in the DBR mirrors. By evaluating experimental measurements of the light output and voltage characteristics over a large range of temperature and diameter, wafer-characteristic parameters are extracted allowing to predict the performance of VCSELs made from this material in any array and assembly configuration. This approach has several beneficial outcomes: Firstly, it gives a general description of a VCSEL independent of its geometry, mounting and detuning, secondly, insights into the structure and the underlying physics can be gained that lead to the improvement potential of the structure and thirdly the performance of the structure in arrays and modules can be predicted. Experimental results validate the approach and demonstrate the significantly improved VCSEL efficiency and the benefit in high power systems.

  11. Highly-efficient high-power pumps for fiber lasers

    Science.gov (United States)

    Gapontsev, V.; Moshegov, N.; Berezin, I.; Komissarov, A.; Trubenko, P.; Miftakhutdinov, D.; Berishev, I.; Chuyanov, V.; Raisky, O.; Ovtchinnikov, A.

    2017-02-01

    We report on high efficiency multimode pumps that enable ultra-high efficiency high power ECO Fiber Lasers. We discuss chip and packaged pump design and performance. Peak out-of-fiber power efficiency of ECO Fiber Laser pumps was reported to be as high as 68% and was achieved with passive cooling. For applications that do not require Fiber Lasers with ultimate power efficiency, we have developed passively cooled pumps with out-of-fiber power efficiency greater than 50%, maintained at operating current up to 22A. We report on approaches to diode chip and packaged pump design that possess such performance.

  12. High Gain Printed Phased Array for SAR Applications Using Planar Electromagnetic Band-Gap Technology

    NARCIS (Netherlands)

    Llombart, N.; Neto, A.; Gerini, G.

    2006-01-01

    This paper shows how the design of integrated arrays can significantly benefit from Planar Circularly Symmetric (PCS) Electromagnetic Band Gap (EBG) structures. Using this technology, a phased array that scans up to 40o in one dimension and that is characterized by relatively large bandwidth (BW ≈

  13. Active beam integrator for high power coherent lasers

    Energy Technology Data Exchange (ETDEWEB)

    Laguarta, F.; Armengol, J.; Vega, F.; Lupon, N. [Univ. Politecnica de Catalunya, Terrassa (Spain). Dept. d`Optica i Optometria

    1996-12-31

    In laser materials processing applications it is often necessary to work with uniform intensity distributions. This goal is quite difficult to achieve when dealing with high power laser beams, and becomes critical for a successful application involving surface heat treatment of non-metallic materials. The authors have designed and tested a very simple beam shaper for transforming the initial intensity distribution of a CO{sub 2} laser beam mode into a more uniform intensity profile. The beam shaper is a two-faceted mirror for active integration of high power coherent laser beams. After reflection in the faceted mirror, a TEM00 or TEM01 CO{sub 2} laser beam is divided into two beamlets that overlap to give a more uniform intensity distribution. A sharp interference pattern due to the high spatial coherence of the incident beam appears. This interference pattern is actively integrated by a high-frequency longitudinal displacement of one of the facets. This provides a change in the relative phase of the two beamlets, and consequently the interference pattern vibrates and its contribution to the intensity distribution averages out. When sweeping this distribution over a sample, a uniform amount of energy is deposited at every point of its surface. It must be emphasized that unlike multifaceted mirrors, the two-facet integrator may provide uniform intensity profiles over any working distance. Finally, as in other integration devices an imaging system may be used to obtain a spot of the shape and the size desired for a particular application.

  14. Material Processing with High Power CO2-Lasers

    Science.gov (United States)

    Bakowsky, Lothar

    1986-10-01

    After a period of research and development lasertechnique now is regarded as an important instrument for flexible, economic and fully automatic manufacturing. Especially cutting of flat metal sheets with high power C02-lasers and CNC controlled two or three axes handling systems is a wide spread. application. Three dimensional laser cutting, laser-welding and -heat treatment are just at the be ginning of industrial use in production lines. The main. advantages of laser technology. are - high. accuracy - high, processing velocity - law thermal distortion. - no tool abrasion. The market for laser material processing systems had 1985 a volume of 300 Mio S with growth rates between, 20 % and 30 %. The topic of this lecture are hiTrh. power CO2-lasers. Besides this systems two others are used as machining tools, Nd-YAG- and Eximer lasers. All applications of high. power CO2-lasers to industrial material processing show that high processing velocity and quality are only guaranteed in case of a stable intensity. profile on the workpiece. This is only achieved by laser systems without any power and mode fluctuations and by handling systems of high accuracy. Two applications in the automotive industry are described, below as examples for laser cutting and laser welding of special cylindrical motor parts.

  15. Splitting of high power, cw proton beams

    CERN Document Server

    Facco, Alberto; Berkovits, Dan; Yamane, Isao; 10.1103/PhysRevSTAB.10.091001

    2007-01-01

    A simple method for splitting a high power, continuous wave (cw) proton beam in two or more branches with low losses has been developed in the framework of the EURISOL (European Isotope Separation On-Line adioactive Ion Beam Facility) design study. The aim of the system is to deliver up to 4 MW of H beam to the main radioactive ion beam production target, and up to 100 kWof proton beams to three more targets, simultaneously. A three-step method is used, which includes magnetic neutralization of a fractionof the main H- beam, magnetic splitting of H- and H0, and stripping of H0 to H+. The method allowsslow raising and individual fine adjustment of the beam intensity in each branch.

  16. Earthquake Triggering by High Power Electric Pulses

    Science.gov (United States)

    Novikov, Victor; Konev, Yuri; Zeigarnik, Vladimir

    2010-05-01

    The study carried out by the Joint Institute for High Temperatures in cooperation with the Institute of Physics of the Earth and the Research Station in Bishkek of Russian Academy of Sciences in 1999-2008 showed a response of weak seismicity at field experiments with electric pulsed power systems, as well as acoustic emission of rock specimens under laboratory conditions on high-power electric current pulses applied to the rocks. It was suggested that the phenomenon discovered may be used in practice for partial release of tectonic stresses in the Earth crust for earthquake hazard mitigation. Nevertheless, the mechanism of the influence of man-made electromagnetic field on the regional seismicity is not clear yet. One of possible cause of the phenomenon may be pore fluid pressure increase in the rocks under stressed conditions due to Joule heat generation by electric current injected into the Earth crust. It is known that increase of pore fluid pressure in the fault zone over a critical pressure of about 0.05 MPa is sufficient to trigger an earthquake if the fault is near the critical state due to accumulated tectonic deformations. Detailed 3D-calculaton of electric current density in the Earth crust of the Northern Tien Shan provided by pulsed electric high-power system connected to grounded electric dipole showed that at the depth of earthquake epicenters (over 5 km) the electric current density is lower than 10-7 A/m2 that is not sufficient for increase of pressure in the fluid-saturated porous geological medium due to Joule heat generation, which may provide formation of cracks resulting in the fault propagation and release of tectonic stresses in the Earth crust. Nevertheless, under certain conditions, when electric current will be injected into the fault through the casing pipes of two deep wells with preliminary injection of conductive fluid into the fault, the current density may be high enough for significant increase of mechanic pressure in the porous two

  17. BBO sapphire compound for high-power frequency conversion

    Science.gov (United States)

    Rothhardt, Carolin; Rothhardt, Jan; Klenke, Arno; Peschel, Thomas; Eberhardt, Ramona; Limpert, Jens; Tünnermann, Andreas

    2015-02-01

    Lasers used for diverse applications from industry to fundamental science tend to increasing output powers. Some applications require frequency conversion via nonlinear optical crystals, which suffer from the formation of temperature gradients at high power operation which causes thermal lensing or destruction of the crystal due to tensile stresses. To avoid these unwanted effects we joined a beta barium borate (BBO) crystal with sapphire disks serving as effective heat spreaders due to their high thermal conductivity (thermal conductivity κ = 42 W/Km). Therefore, smooth and flat crystal surfaces were joined by plasma-activated bonding. The joining relies on covalent bonds, which are formed via a condensation reaction of the surfaces which are first connected by Van der Waals forces. The cleaned surfaces are activated by plasma and brought into contact, pressed together and heat treated at a temperature of about 100°C. Special attention has been paid to the cleaning of the surfaces. Therefor the surfaces have been evaluated before and after treatment by means of atomic force microscopy. A stable connection has been formed successfully, which has been tested in a proof of principle experiment and demonstrated efficient second harmonic generation at up to 253 W of input power. Compared to a bare single BBO crystal it could be shown that the temperature within the crystal compound is significantly reduced. Such hybrid structures pave the way for frequency conversion at kilowatts of average power for future high power lasers.

  18. High power diode lasers for solid-state laser pumps

    Science.gov (United States)

    Linden, Kurt J.; Mcdonnell, Patrick N.

    1994-01-01

    The development and commercial application of high power diode laser arrays for use as solid-state laser pumps is described. Such solid-state laser pumps are significantly more efficient and reliable than conventional flash-lamps. This paper describes the design and fabrication of diode lasers emitting in the 780 - 900 nm spectral region, and discusses their performance and reliability. Typical measured performance parameters include electrical-to-optical power conversion efficiencies of 50 percent, narrow-band spectral emission of 2 to 3 nm FWHM, pulsed output power levels of 50 watts/bar with reliability values of over 2 billion shots to date (tests to be terminated after 10 billion shots), and reliable operation to pulse lengths of 1 ms. Pulse lengths up to 5 ms have been demonstrated at derated power levels, and CW performance at various power levels has been evaluated in a 'bar-in-groove' laser package. These high-power 1-cm stacked-bar arrays are now being manufactured for OEM use. Individual diode laser bars, ready for package-mounting by OEM customers, are being sold as commodity items. Commercial and medical applications of these laser arrays include solid-state laser pumping for metal-working, cutting, industrial measurement and control, ranging, wind-shear/atmospheric turbulence detection, X-ray generation, materials surface cleaning, microsurgery, ophthalmology, dermatology, and dental procedures.

  19. Solution to the initial value problem for a high-gain FEL via Van Kampen's method

    CERN Document Server

    Huang Zhi Rong

    2001-01-01

    Using Van Kampen's normal mode expansion, we solve the initial value problem for a high-gain free-electron laser described by the three-dimensional Maxwell-Klimontovich equations. An expression of the radiation spectrum is given for the process of coherent amplification and self-amplified spontaneous emission. It is noted that the input coupling coefficient for either process increases with the initial beam energy spread. The effective start-up noise is identified as the coherent fraction of the spontaneous undulator radiation in one field gain length, and is larger with increasing energy spread and emittance mainly because of the increase in gain length.

  20. Millimeter Wave Fabry-Perot Resonator Antenna Fed by CPW with High Gain and Broadband

    OpenAIRE

    Xue-Xia Yang; Guan-Nan Tan; Bing Han; Hai-Gao Xue

    2016-01-01

    A novel millimeter wave coplanar waveguide (CPW) fed Fabry-Perot (F-P) antenna with high gain, broad bandwidth, and low profile is reported. The partially reflective surface (PRS) and the ground form the F-P resonator cavity, which is filled with the same dielectric substrate. A dual rhombic slot loop on the ground acts as the primary feeding antenna, which is fed by the CPW and has broad bandwidth. In order to improve the antenna gain, metal vias are inserted surrounding the F-P cavity. A CP...

  1. THE HIGH GAIN CO2 LASER BY EFFECTIVE MIXING OF N2 AND CO2 GAS

    OpenAIRE

    Hara, H.; Fujisawa, A.

    1980-01-01

    A high-gain CO2 laser is described in which vibrationally excited N2 gas and cold CO2 gas are mixed effectively by means of the diffusion of CO2 gas into N2 gas. By using different types of mixing techniques, a maximum gain of 11 m-1 was obtained when CO2 gas was injected parallel to the expanding N2 gas flow. An output power of 4 W was obtained from an 1.2 cm active length. In addition, He gas addition to the N2 gas flow was found to decrease the small-signal gain with increasing He gas flow...

  2. [Development of a High Power Green Laser Therapeutic Equipment for Hyperplasia of Prostate].

    Science.gov (United States)

    Liang, Jie; Kang, Hongxiang; Shen, Benjian; Zhao, Lusheng; Wu, Xinshe; Chen, Peng; Chang, Aihong; Guo Hua; Guo, Jiayu

    2015-09-01

    The basic theory of high power green laser equipment for prostate hyperplasia therapy and the components of the system developed are introduced. Considering the requirements of the clinical therapy, the working process of the high power green laser apparatus are designed and the laser with stable output at 120 W is achieved. The controlling hardware and application software are developed, and the safety step is designed. The high power green laser apparatus manufactured with characteristics of stable output, multifunctional and friendly interface provides a choices of prostate hyperplasia therapy for using nationalization instrument.

  3. High power density dc/dc converter: Component selection and design

    Science.gov (United States)

    Divan, Deepakraj M.

    Further work pertaining to design considerations for the new high power, high frequency dc/dc converters is discussed. The goal of the project is the development of high power, high power density dc/dc converters at power levels in the multi-kilowatt to megawatt range for aerospace applications. The prototype converter is rated for 50 kW at a switching frequency of 50 kHz, with an input voltage of 200 Vdc and an output of 2000 Vdc. The overall power density must be in the vicinity of 0.2 to 0.3 kg/kW.

  4. Design and characterization of a novel power over fiber system integrating a high power diode laser

    Science.gov (United States)

    Perales, Mico; Yang, Mei-huan; Wu, Cheng-liang; Hsu, Chin-wei; Chao, Wei-sheng; Chen, Kun-hsein; Zahuranec, Terry

    2017-02-01

    High power 9xx nm diode lasers along with MH GoPower's (MHGP's) flexible line of Photovoltaic Power Converters (PPCs) are spurring high power applications for power over fiber (PoF), including applications for powering remote sensors and sensors monitoring high voltage equipment, powering high voltage IGBT gate drivers, converters used in RF over Fiber (RFoF) systems, and system power applications, including powering UAVs. In PoF, laser power is transmitted over fiber, and is converted to electricity by photovoltaic cells (packaged into Photovoltaic Power Converters, or PPCs) which efficiently convert the laser light. In this research, we design a high power multi-channel PoF system, incorporating a high power 976 nm diode laser, a cabling system with fiber break detection, and a multichannel PPC-module. We then characterizes system features such as its response time to system commands, the PPC module's electrical output stability, the PPC-module's thermal response, the fiber break detection system response, and the diode laser optical output stability. The high power PoF system and this research will serve as a scalable model for those interested in researching, developing, or deploying a high power, voltage isolated, and optically driven power source for high reliability utility, communications, defense, and scientific applications.

  5. In-circuit-measurement of parasitic elements in high gain high bandwidth low noise transimpedance amplifiers.

    Science.gov (United States)

    Cochems, P; Kirk, A; Zimmermann, S

    2014-12-01

    Parasitic elements play an important role in the development of every high performance circuit. In the case of high gain, high bandwidth transimpedance amplifiers, the most important parasitic elements are parasitic capacitances at the input and in the feedback path, which significantly influence the stability, the frequency response, and the noise of the amplifier. As these parasitic capacitances range from a few picofarads down to only a few femtofarads, it is nearly impossible to measure them accurately using traditional LCR meters. Unfortunately, they also cannot be easily determined from the transfer function of the transimpedance amplifier, as it contains several overlapping effects and its measurement is only possible when the circuit is already stable. Therefore, we developed an in-circuit measurement method utilizing minimal modifications to the input stage in order to measure its parasitic capacitances directly and with unconditional stability. Furthermore, using the data acquired with this measurement technique, we both proposed a model for the complicated frequency response of high value thick film resistors as they are used in high gain transimpedance amplifiers and optimized our transimpedance amplifier design.

  6. A Vehicle Haptic Steering by Wire System Based on High Gain GPI Observers

    Directory of Open Access Journals (Sweden)

    A. Rodriguez-Angeles

    2014-01-01

    Full Text Available A vehicle steering by wire (SBW haptic system based on high gain generalized proportional integral (GPI observers is introduced. The observers are considered for the estimation of dynamic perturbations that are present at the tire and steering wheel. To ensure efficient tracking between the commanded steering wheel angle and the tire orientation angle, the estimated perturbations are on line canceled. As to provide a haptic interface with the driver, the estimated dynamic effects at the steering rack are fed back to the steering wheel, yielding a master-slave haptic system with bilateral communication. For implementation purposes few sensors and minimum knowledge of the dynamic model are required, which is a major advantage compared to other approaches. Only position tracking errors are fed back, while all other signals are estimated by the high gain GPI observers. The scheme is robust to uncertainty on the input gain and cancels dynamic perturbation effects such as friction and aligning forces on the tire. Experimental results are presented on a prototype platform.

  7. Novel High-Gain Circularly Polarized Lens Antenna Using Single-Layer Transmissive Metasurface

    Science.gov (United States)

    Zhuang, Yaqiang; Wang, Guangming; Li, Haipeng; Guo, Wenlong

    2017-05-01

    A high-gain lens antenna employing single-layer focusing metasurface (MS) is proposed in this article. The single-layer element achieves a 360° transmission phase range with a transmission magnitude better than 0.9. And the focusing MS consists of 169 elements was designed by utilizing the technique of varying rotation angle to compensate the phase delay. Thus, a lens antenna is constructed by placing a circularly polarized (CP) patch antenna at the focal point of the MS. The fabricated lens antenna demonstrates a good performance of 4.6 % 3-dB axial ratio bandwidth and 6 % 1-dB gain bandwidth, respectively. Moreover, the maximum gain is 18.3 dBic at 15 GHz, which is enhanced by 11.4 dBic compared with the patch antenna. Due to the single-layer structure, this design has a low profile and easy fabrication process compared with the conventional designs, making it an attractive alternative to compact high-gain antenna.

  8. The general solution of the eigenvalue problem for a high-gain FEL

    CERN Document Server

    Saldin, E L; Yurkov, M V

    2001-01-01

    The exact solution of the eigenvalue equation for a high-gain FEL derived in Xie (Nucl. Instr. and Meth. A 445 (2000) 59) is generalized in order to include the space charge effects. This solution is valid not only for natural undulator focusing, but also for alternating-gradient focusing under some condition that is presented. At such, the obtained solution includes all the important effects in the system of axially homogeneous electron beam and undulator: diffraction, betatron motion, energy spread, space charge and frequency detuning. It is valid for ground TEM sub 0 sub 0 mode as well as for high-order modes and can be used for calculation of high-gain FEL amplifiers operating in the wavelength regions from far infrared down to X-ray. In addition, a computationally efficient approximate solution for TEM sub 0 sub 0 mode is derived providing high accuracy (better than 1% in the whole range of parameters). It can be used for quick optimization of FEL amplifiers.

  9. High Gain Submicrometer Optical Amplifier at Near-Infrared Communication Band.

    Science.gov (United States)

    Wang, Xiaoxia; Zhuang, Xiujuan; Yang, Sen; Chen, Yu; Zhang, Qinglin; Zhu, Xiaoli; Zhou, Hong; Guo, Pengfei; Liang, Junwu; Huang, Yu; Pan, Anlian; Duan, Xiangfeng

    2015-07-10

    Nanoscale near-infrared optical amplification is important but remains a challenge to achieve. Here we report a unique design of silicon and erbium silicate core-shell nanowires for high gain submicrometer optical amplification in the near-infrared communication band. The high refraction index silicon core is used to tightly confine the optical field within the submicron structures, and the single crystalline erbium-ytterbium silicates shell is used as the highly efficient gain medium. Both theoretical and experimental results show that, by systematically tuning the core diameter and shell thickness, a large portion of the optical power can be selectively confined to the erbium silicate shell gain medium to enable a low loss waveguide and high gain optical amplifier. Experimental results further demonstrate that an optimized core-shell nanowire can exhibit an excellent net gain up to 31  dB mm(-1), which is more than 20 times larger than the previously reported best results on the micron-scale optical amplifiers.

  10. High power diode lasers converted to the visible

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Hansen, Anders Kragh; Andersen, Peter E.

    2017-01-01

    High power diode lasers have in recent years become available in many wavelength regions. However, some spectral regions are not well covered. In particular, the visible spectral range is lacking high power diode lasers with good spatial quality. In this paper, we highlight some of our recent...... results in nonlinear frequency conversion of high power near infrared diode lasers to the visible spectral region....

  11. Simulation of High Power Amplifier Calculation in VSAT System

    Directory of Open Access Journals (Sweden)

    Indri Neforawati

    2009-08-01

    Full Text Available Arithmatical simulation of High Power Amplifier (HPA on VSAT system is a program which used to calculate the capacity of HPA as a working test of maximum power on each remote station of the VSAT network system, afterward can be obtained the available capacity value and power capacity used, therefore able to reallocate residual power below its available power spare. VSAT system can be used for several telecommunication application such as video broadcast, data broadcast,audio broadcast, banking operation, ATM and others. Due to the easy operational, maintanance and its instalment, VSAT system is more prifitable compare to ordinary terestrial band, its capability for multiservice application become more flexible in using its network. The software used is Visual Basic 6.0 version and database Microsoft Access. These software take a role as visualization and planning for remote station development and also power capasity needed for each remote in the calculation of HPA.

  12. Laminar composite structures for high power actuators

    Science.gov (United States)

    Hobosyan, M. A.; Martinez, P. M.; Zakhidov, A. A.; Haines, C. S.; Baughman, R. H.; Martirosyan, K. S.

    2017-05-01

    Twisted laminar composite structures for high power and large-stroke actuators based on coiled Multi Wall Carbon Nanotube (MWNT) composite yarns were crafted by integrating high-density Nanoenergetic Gas Generators (NGGs) into carbon nanotube sheets. The linear actuation force, resulting from the pneumatic force caused by expanding gases confined within the pores of laminar structures and twisted carbon nanotube yarns, can be further amplified by increasing NGG loading and yarns twist density, as well as selecting NGG compositions with high energy density and large-volume gas generation. Moreover, the actuation force and power can be tuned by the surrounding environment, such as to increase the actuation by combustion in ambient air. A single 300-μm-diameter integrated MWNT/NGG coiled yarn produced 0.7 MPa stress and a contractile specific work power of up to 4.7 kW/kg, while combustion front propagated along the yarn at a velocity up to 10 m/s. Such powerful yarn actuators can also be operated in a vacuum, enabling their potential use for deploying heavy loads in outer space, such as to unfold solar panels and solar sails.

  13. Test of a High Power Target Design

    CERN Multimedia

    2002-01-01

    %IS343 :\\\\ \\\\ A high power tantalum disc-foil target (RIST) has been developed for the proposed radioactive beam facility, SIRIUS, at the Rutherford Appleton Laboratory. The yield and release characteristics of the RIST target design have been measured at ISOLDE. The results indicate that the yields are at least as good as the best ISOLDE roll-foil targets and that the release curves are significantly faster in most cases. Both targets use 20 -25 $\\mu$m thick foils, but in a different internal geometry.\\\\ \\\\Investigations have continued at ISOLDE with targets having different foil thickness and internal geometries in an attempt to understand the release mechanisms and in particular to maximise the yield of short lived isotopes. A theoretical model has been developed which fits the release curves and gives physical values of the diffusion constants.\\\\ \\\\The latest target is constructed from 2 $\\mu$m thick tantalum foils (mass only 10 mg) and shows very short release times. The yield of $^{11}$Li (half-life of ...

  14. High-Power Helicon Double Gun Thruster

    Science.gov (United States)

    Murakami, Nao

    While chemical propulsion is necessary to launch a spacecraft from a planetary surface into space, electric propulsion has the potential to provide significant cost savings for the orbital transfer of payloads between planets. Due to extended wave particle interactions, a plasma thruster that can operate in the 100 kW to several MW power regime can only be attained by increasing the size of the thruster, or by using an array of plasma thrusters. The High-Power Helicon (HPH) Double Gun thruster experiment examines whether firing two helicon thrusters in parallel produces an exhaust velocity higher than the exhaust velocity of a single thruster. The scaling law that relates the downstream plasma velocity with the number of helicon antennae is derived, and compared with the experimental result. In conjunction with data analysis, two digital filtering algorithms are developed to filter out the noise from helicon antennae. The scaling law states that the downstream plasma velocity is proportional to square root of the number of helicon antennae, which is in agreement with the experimental result.

  15. Temperature measurements of high power LEDs

    Science.gov (United States)

    Badalan (Draghici), Niculina; Svasta, Paul; Drumea, Andrei

    2016-12-01

    Measurement of a LED junction temperature is very important in designing a LED lighting system. Depending on the junction temperature we will be able to determine the type of cooling system and the size of the lighting system. There are several indirect methods for junction temperature measurement. The method used in this paper is based on the thermal resistance model. The aim of this study is to identify the best device that would allow measuring the solder point temperature and the temperature on the lens of power LEDs. For this purpose four devices for measuring temperature on a high-power LED are presented and compared according to the acquired measurements: an infrared thermal camera from FLIR Systems, a multimeter with K type thermocouple (Velleman DVM4200), an infrared-spot based noncontact thermometer (Raynger ST) and a measurement system based on a digital temperature sensor (DS1821 type) connected to a PC. The measurements were conducted on an 18W COB (chip-on-board) LED. The measurement points are the supply terminals and the lens of the LED.

  16. Very high-gain and low-excess noise near-infrared single-photon avalanche detector: an NIR solid state photomultiplier

    Science.gov (United States)

    Linga, Krishna; Yevtukhov, Yuriy; Liang, Bing

    2009-05-01

    A new family of photodetectors with a Discrete Amplification (DA) mechanism allows the realization of very high gain and low excess noise factor in the visible and near infrared spectral regions and offers an alternative to conventional photomultiplier tubes and Geiger mode avalanche photodetectors. These photodetectors can operate in linear detection mode with gain-bandwidth product in excess of 4X1014 and in photon counting mode with count rates up to 108 counts/sec. Potential benefits of this technology over conventional avalanche photodetectors include ultra low excess noise factor, very high gain, and lower reset time ( 2X105, excess noise factor researchers in the field of deep space optical communication, spectroscopy, industrial and scientific instrumentation, Ladar/Lidar, quantum cryptography, night vision and other military, defence and aerospace applications.

  17. Reliability of high-power multimode pump modules

    Science.gov (United States)

    Pflueger, Silke; Duesterberg, Richard L.; Rossin, Victor V.; Strite, Toby; Tai, Kuochou; Wolak, Edmund L.; Wong, Andre W.; Xu, Lei; Zucker, Erik

    2004-10-01

    Developers building high-power fiber lasers and diode pumped solid state lasers can receive significant benefits in thermal management and reliability by using single emitter multi-mode diodes in distributed pump architectures. This proposed distributed architecture relies on independent single emitter pump lasers and a modest level of pump redundancy. Driving the remaining diodes slightly harder componensates individual diode failures. A model of the ensemble lifetime based on module failure rates and power-scaling factors demonstrates that the distributed pump architecture requires random failure rates corresponding to better than 200,000h mean time between failure (MTBF), which meets typical industrial requirements. A high power, pigtailed, multi-mode pump module suitable for commercial applications is created through this model. Critical elements are based on telecom architectures, including the optical train and the fiber alignment. The module has a low thermal resistance of 4°C/W from the chip-on-sub-mount to the external heat sink, coupling efficiency of over 80% into 0.2 NA, and demonstrated reliable output power of over 5W cw with peak wavelengths near 915 nm. Individual pump modules are predicted to produce 5W cw output power with an MTBF of more than 400,000h. The relationship between anticipated MTBF requirements, test duration and test population is shown.

  18. High-power CO lasers for materials processing

    Science.gov (United States)

    Averin, A.; Erofeev, E.; Ionin, Andrei A.; Malysh, M.

    1994-08-01

    Two high-power CO laser installations for industrial applications are being developed now in Russia within the framework of the Eureka Project EU113 (`CO-Eurolaser'). The electron- beam-controlled-discharge (EBCD) method for pumping those lasers is used. The first one, EBCD 10 kW CO laser, operates in continuous wave and `gentle' repetitively pulsed (RP) (peak power 20 kW, laser pulse duration 0.5 - 1 ms, pulse repetition rate 500 - 1,000 Hz) modes. The second laser, EBCD 5 - 10 kW CO laser will operate in `tough' RP mode (peak power 0.2 - 1.0 MW, single pulse energy 100 J, pulse duration 0.1 - 0.5 ms, repetition rate 50 - 100 Hz). A detander-compressor device, the main characteristics of which are reported, will be used for cooling the laser mixture of the second CO laser. Those high-power CO laser installations are supposed to be used for investigation of different laser materials processing methods on 5 micrometers wavelength for deep penetration welding, cutting, and surface treatment and also for comparative materials processing studies on CO and CO2 laser wavelengths.

  19. High-Power Lasers for Science and Society

    Energy Technology Data Exchange (ETDEWEB)

    Siders, C. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Haefner, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-05

    Since the first demonstration of the laser in 1960 by Theodore Maiman at Hughes Research Laboratories, the principal defining characteristic of lasers has been their ability to focus unprecedented powers of light in space, time, and frequency. High-power lasers have, over the ensuing five and a half decades, illuminated entirely new fields of scientific endeavor as well as made a profound impact on society. While the United States pioneered lasers and their early applications, we have been eclipsed in the past decade by highly effective national and international networks in both Europe and Asia, which have effectively focused their energies, efforts, and resources to achieve greater scientific and societal impact. This white paper calls for strategic investment which, by striking an appropriate balance between distributing our precious national funds and establishing centers of excellence, will ensure a broad pipeline of people and transformative ideas connecting our world-leading universities, defining flagship facilities stewarded by our national laboratories, and driving innovation across industry, to fully exploit the potential of high-power lasers.

  20. High-power 95 GHz pulsed electron spin resonance spectrometer

    Science.gov (United States)

    Hofbauer, W.; Earle, K. A.; Dunnam, C. R.; Moscicki, J. K.; Freed, J. H.

    2004-05-01

    High-field/high-frequency electron spin resonance (ESR) offers improved sensitivity and resolution compared to ESR at conventional fields and frequencies. However, most high-field/high-frequency ESR spectrometers suffer from limited mm-wave power, thereby requiring long mm-wave pulses. This precludes their use when relaxation times are short, e.g., in fluid samples. Low mm-wave power is also a major factor limiting the achievable spectral coverage and thereby the multiplex advantage of Fourier transform ESR (FTESR) experiments. High-power pulses are needed to perform two-dimensional (2D) FTESR experiments, which can unravel the dynamics of a spin system in great detail, making it an excellent tool for studying spin and molecular dynamics. We report on the design and implementation of a high-power, high-bandwidth, pulsed ESR spectrometer operating at 95 GHz. One of the principal design goals was the ability to investigate dynamic processes in aqueous samples at physiological temperatures with the intent to study biological systems. In initial experiments on aqueous samples at room temperature, we achieved 200 MHz spectral coverage at a sensitivity of 1.1×1010√s spins and a dead time of less than 50 ns. 2D-electron-electron double resonance experiments on aqueous samples are discussed to demonstrate the practical application of such a spectrometer.

  1. High power 1060-nm super large vertical cavity semiconductor lasers

    Science.gov (United States)

    Tan, Shaoyang; Zhai, Teng; Wang, Wei; Zhang, Ruikang; Lu, Dan; Ji, Chen

    2014-11-01

    High power single-mode ridge waveguide 1060-nm semiconductor lasers are reported. The lasers consist of compressively strained double InGaAs/GaAs quantum wells and a GaAs/AlGaAs separate confinement vertical structure. A super large vertical optical cavity is employed to have a low internal loss, large optical spot size and low vertical optical divergence angle. The material composition and thickness of waveguide layers and claddings layer are optimized systematically. The active layer is detuned from center of the waveguide and thickness of cladding layers is optimized to guaranty single mode lasing of the large optical cavity. The large vertical cavity laser structure with thickness of 4 μm allows the lasers have a low internal loss of less than 0.6 /cm, a large optical spot size about 1μm and a vertical divergence angle about 20 degree. For lateral optical confinement, a double trench ridge waveguide is employed to maintain single-lateral-mode operation. Based on the optimization, 1.5 W continue wave optical power is achieved for broad area lasers with 1mm longitude cavity length. Narrow stripe ridge waveguide lasers of 1mm cavity length with single mode current and optical power of 700 mA and 340 mW is obtained. Suggestions for further improvements in terms of single mode power and applications of the high power semiconductors are discussed.

  2. Enhanced stability of magnetoelectric gyrators under high power conditions

    Science.gov (United States)

    Leung, Chung Ming; Zhuang, Xin; Gao, Min; Tang, Xiao; Xu, Junran; Li, Jiefang; Zhang, Jitao; Srinivasan, G.; Viehland, D.

    2017-10-01

    In this study, three different coil-based magnetoelectric (ME) gyrators of different geometries, including gyrators with high power output, have been designed and characterized. These included two magnetostrictive/piezoelectric/magnetostrictive (M-P-M) and one piezoelectric/magnetostrictive/piezoelectric (P-M-P) type ME gyrators, which consisted of nickel zinc ferrite (NZFO) and lead zirconate titanate (PZT) ceramic plates. Compared with M-P-M ME gyrators, the P-M-P ones exhibited a higher power efficiency (η) of 85% when operated at resonance under an optimal magnetic bias field (HBias) of 40 Oe at low power conditions. It retained a relatively high efficiency of η = 79% under a high input power density of 2.87 W/cm3. A low reduction in the magnetomechanical coupling and mechanical quality (k33,m and Qm) factors of the NZFO ferrite layer in the ME gyrator explains the resilience of the P-M-P type structure with increasing power drive. The findings open the possibility of using ME gyrators in high power applications.

  3. High power compatible internally sensed optical phased array.

    Science.gov (United States)

    Roberts, Lyle E; Ward, Robert L; Francis, Samuel P; Sibley, Paul G; Fleddermann, Roland; Sutton, Andrew J; Smith, Craig; McClelland, David E; Shaddock, Daniel A

    2016-06-13

    The technical embodiment of the Huygens-Fresnel principle, an optical phased array (OPA) is an arrangement of optical emitters with relative phases controlled to create a desired beam profile after propagation. One important application of an OPA is coherent beam combining (CBC), which can be used to create beams of higher power than is possible with a single laser source, especially for narrow linewidth sources. Here we present an all-fiber architecture that stabilizes the relative output phase by inferring the relative path length differences between lasers using the small fraction of light that is back-reflected into the fiber at the OPA's glass-air interface, without the need for any external sampling optics. This architecture is compatible with high power continuous wave laser sources (e.g., fiber amplifiers) up to 100 W per channel. The high-power compatible internally sensed OPA was implemented experimentally using commercial 15 W fiber amplifiers, demonstrating an output RMS phase stability of λ/194, and the ability to steer the beam at up to 10 kHz.

  4. The Jefferson Lab High Power Light Source

    Energy Technology Data Exchange (ETDEWEB)

    James R. Boyce

    2006-01-01

    Jefferson Lab has designed, built and operated two high average power free-electron lasers (FEL) using superconducting RF (SRF) technology and energy recovery techniques. Between 1999-2001 Jefferson Lab operated the IR Demo FEL. This device produced over 2 kW in the mid-infrared, in addition to producing world record average powers in the visible (50 W), ultraviolet (10 W) and terahertz range (50 W) for tunable, short-pulse (< ps) light. This FEL was the first high power demonstration of an accelerator configuration that is being exploited for a number of new accelerator-driven light source facilities that are currently under design or construction. The driver accelerator for the IR Demo FEL uses an Energy Recovered Linac (ERL) configuration that improves the energy efficiency and lowers both the capital and operating cost of such devices by recovering most of the power in the spent electron beam after optical power is extracted from the beam. The IR Demo FEL was de-commissioned in late 2001 for an upgraded FEL for extending the IR power to over 10 kW and the ultraviolet power to over 1 kW. The FEL Upgrade achieved 10 kW of average power in the mid-IR (6 microns) in July of 2004, and its IR operation currently is being extended down to 1 micron. In addition, we have demonstrated the capability of on/off cycling and recovering over a megawatt of electron beam power without diminishing machine performance. A complementary UV FEL will come on-line within the next year. This paper presents a summary of the FEL characteristics, user community accomplishments with the IR Demo, and planned user experiments.

  5. In vitro study of 960 nm high power diode laser applications in dental enamel, aided by the presence of a photoinitiator dye: scanning electron microscopy analysis; Estudo in vitro das aplicacoes do laser de diodo de alta potencia 960 nm em esmalte dentario, assistido por um fotoiniciador: analise de microscopia eletronica de varredura

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Marcelo Vinicius de

    2002-06-15

    The objective of this study is to verify if a high power diode laser can effectively modify the morphology of an enamel surface, and if this can be done in a controlled fashion by changing the lasers parameters. Previous studies using SEM demonstrated that through irradiation with Nd:YAG laser (1064 nm) it is possible to modify the morphology of the dental surface in such way as to increase its resistance against caries decays. The desired procedures that should achieve a decrease of the index of caries decays and of its sequels are on a primary level, which means that action is necessary before the disease installs itself. In this study it was used for the first time a prototype of a high power diode laser operating at 960 nm, produced by the Laboratory of Development of Lasers of the Center for Lasers and Applications of the IPEN. This equipment can present several advantages as reliability, reduced size and low cost. The aim was establish parameters of laser irradiation that produce the desired effects wanted in the enamel and protocols that guarantee its safety during application in dental hard tissues, protecting it of heating effects such as fissures and carbonization. (author)

  6. DEMONSTRATION OF 3D EFFECTS WITH HIGH GAIN AND EFFICIENCY IN A UV FEL OSCILLATOR

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Benson; George Biallas; Keith Blackburn; James Boyce; Donald Bullard; James Coleman; Cody Dickover; David Douglas; Forrest Ellingsworth; Pavel Evtushenko; Carlos Hernandez-Garcia; Christopher Gould; Joseph Gubeli; David Hardy; Kevin Jordan; John Klopf; James Kortze; Robert Legg; Matthew Marchlik; Steven Moore; George Neil; Thomas Powers; Daniel Sexton; Michelle D. Shinn; Christopher Tennant; Richard Walker; Anne Watson; Gwyn Williams; Frederick Wilson; Shukui Zhang

    2011-03-01

    We report on the performance of a high gain UV FEL oscillator operating on an energy recovery linac at Jefferson Lab. The high brightness of the electron beam leads to both gain and efficiency that cannot be reconciled with a one-dimensional model. Three-dimensional simulations do predict the performance with reasonable precision. Gain in excess of 100% per pass and an efficiency close to 1/2NW, where NW is the number of wiggler periods, is seen. The laser mirror tuning curves currently permit operation in the wavelength range of 438 to 362 nm. Another mirror set allows operation at longer wavelengths in the red with even higher gain and efficiency.

  7. Study on the drive laser system of the photocathode-injector used in high gain FEL

    CERN Document Server

    Lu Xiang Yang; Zhao Kui; Wang Li; Quan Sheng Wen; Hao Jian Kui; Zhang Bao Cheng; Chen J

    2002-01-01

    High gain FEL requires high quality electron beam which can be provided only by the RF photocathode gun. The drive laser for electron source plays the key role. In Institute of Heavy Ion Physics of Beijing University, the laser system is required to deliver a 500 mu J, 6-8 ps pulse of UV photons (260 nm) to the cathode. This system mainly consists of a CW, frequency-doubled, diode-pumped Nd:YAG laser, which provides energy to pump a CW mode-locked Ti:sapphire oscillator, Q-switched Nd:YaG pump lasers, a regenerative amplifier and harmonics crystals. To meet the low jitters of pulses (1.0 ps), cavity length of the oscillator should be adjustable to lock the pulse frequency with external RF reference, and a phase stability feedback system is also used

  8. New results of the high-gain harmonic generation free-electron laser experiment

    CERN Document Server

    Doyuran, A; Ben-Zvi, I; Biedron, S G; Di Mauro, Louis F; Graves, W; Jagger, J M; Johnson, E; Krinsky, S; Malone, R; Pogorelsky, I V; Rakowsky, G; Sajaev, Vadim; Shaftan, T; Skaritka, J; Vasserman, I B; Wang, X J; Woodle, M; Yakimenko, V; Yu, L H

    2001-01-01

    We report on the experimental investigation of high-gain harmonic generation carried out at the Accelerator Test Facility at Brookhaven National Laboratory. A seed CO sub 2 laser at a wavelength of 10.6 mu m was used to generate FEL output at a 5.3-mu m wavelength. The duration of the output pulse was measured using a second-harmonic intensity autocorrelator, and the coherence length was measured using an interferometer. We also measured the energy distribution of the electron beam after it exited the second undulator, observing behavior consistent with that is expected at saturation. The intensity of the harmonic components of the output at 2.65 and 1.77 mu m was determined relative to that of the 5.3-mu m fundamental. Finally, using a corrector magnet upstream of the radiator, steering effects on the trajectories of the electron and light beams were studied.

  9. Utilizing wideband AMC structures for high-gain inkjet-printed antennas on lossy paper substrate

    KAUST Repository

    Cook, Benjamin Stassen

    2013-01-01

    Significant gain and bandwidth improvement of inkjet-printed antennas with integrated artificial magnetic conductor (AMC) is achieved by utilizing wideband ground-backed frequency selective surfaces (FSSs) to overcome the high losses of organic substrates such as paper. A microstrip-fed monopole mounted on an artificial magnetic conductor is demonstrated to improve the gain by 5 dB over previous works and exhibit much wider impedance bandwidth while maintaining a thin antenna profile and a 20% electrical size reduction. The effect of AMC bandwidth on substrate losses and the gain reduction caused by finite AMC array effects are investigated in an effort to produce high-gain, miniaturized, low-cost wearable and structure mount antennas. © 2013 IEEE.

  10. High gain harmonic generation free electron lasers enhanced by pseudoenergy bands

    Directory of Open Access Journals (Sweden)

    Takashi Tanaka

    2017-08-01

    Full Text Available We propose a new scheme for high gain harmonic generation free electron lasers (HGHG FELs, which is seeded by a pair of intersecting laser beams to interact with an electron beam in a modulator undulator located in a dispersive section. The interference of the laser beams gives rise to a two-dimensional modulation in the energy-time phase space because of a strong correlation between the electron energy and the position in the direction of dispersion. This eventually forms pseudoenergy bands in the electron beam, which result in efficient harmonic generation in HGHG FELs in a similar manner to the well-known scheme using the echo effects. The advantage of the proposed scheme is that the beam quality is less deteriorated than in other existing schemes.

  11. A Low Voltage High Gain Transformer Noise-Canceling Current Mode Ultrawideband CMOS Low Noise Amplifier

    Science.gov (United States)

    Sun, Jingru; Cao, Xiaodong; Wang, Chunhua; Liu, Jinjiang; Zhao, Manfeng

    2012-03-01

    This paper presents a novel current mode differential UWB LNA. A common-gate stage with transformer realizes a low noise input matching and produces a current gain. The output of the LNA is differential current, which can avoid the current-to-voltage conversion. The LNA is simulated with TSMC 0.18 μm RF CMOS process. Simulation results show that the max noise figure is only 2.65 dB, transconductance gain is larger than 18.7 dB, input reflection coefficient is lower than -9.9 dB, and third order input intercept point is about 2.8 dBm over 3-5 GHz. With a voltage of 0.8 V, the power consumption is 11 mW. A comparison with conventional UWB LNA shows that this LNA has advantages of low voltage, low noise, high gain, and high linearity.

  12. Spectral Phase Modulation and chirped pulse amplification in High Gain Harmonic Generation

    CERN Document Server

    Wu, Zilu; Krinsky, Sam; Loos, Henrik; Murphy, James; Shaftan, Timur; Sheehy, Brian; Shen, Yuzhen; Wang, Xijie; Yu Li Hua

    2004-01-01

    High Gain Harmonic Generation (HGHG), because it produces longitudinally coherent pulses derived from a coherent seed, presents remarkable possibilities for manipulating FEL pulses. If spectral phase modulation imposed on the seed modulates the spectral phase of the HGHG in a deterministic fashion, then chirped pulse amplification, pulse shaping, and coherent control experiments at short wavelengths become possible. In addition, the details of the transfer function will likely depend on electron beam and radiator dynamics and so prove to be a useful tool for studying these. Using the DUVFEL at the National Synchrotron Light Source at Brookhaven National Laboratory, we present spectral phase analyses of both coherent HGHG and incoherent SASE ultraviolet FEL radiation, applying Spectral Interferometry for Direct Electric Field Reconstruction (SPIDER), and assess the potential for employing compression and shaping techniques.

  13. Design of single-layer high-efficiency transmitting phase-gradient metasurface and high gain antenna

    Science.gov (United States)

    Zhang, Di; Yang, Xiaoqing; Su, Piqiang; Luo, Jiefang; Chen, Huijie; Yuan, Jianping; Li, Lixin

    2017-12-01

    In this paper, based on rotation phase-gradient principle, a single-layer, high-efficiency transmitting metasurface is designed and applied to high-gain antenna. In the case of circularly polarized incident wave, the PCR (polarization conversions ratio) of the metasurface element is greater than 90% in the band of 9.11–10.48 GHz. The transmitting wave emerges an anomalous refraction when left-handed circularly polarized wave are incident perpendicularly to the 1D phase-gradient metasurface, which is composed of cycle arrangement of 6 units with step value of 30°. The simulated anomalous refraction angle is 40.1°, coincided with the theoretical design value (40.6°). For further application, the 2D focused metasurface is designed to enhance the antenna performance while the left-handed circularly polarized antenna is placed at the focus. The simulated max gain is increased by 12 dB (182%) and the half-power beamwidth is reduced by 74.6°. The measured results are coincided with the simulations, which indicates the antenna has high directivity. The designed single-layer transmission metasurface has advantages of thin thickness (only 1.5 mm), high efficiency and light weight, and will have important application prospects in polarization conversion and beam control.

  14. Advanced Electrodes for High Power Li-ion Batteries

    Directory of Open Access Journals (Sweden)

    Christian M. Julien

    2013-03-01

    Full Text Available While little success has been obtained over the past few years in attempts to increase the capacity of Li-ion batteries, significant improvement in the power density has been achieved, opening the route to new applications, from hybrid electric vehicles to high-power electronics and regulation of the intermittency problem of electric energy supply on smart grids. This success has been achieved not only by decreasing the size of the active particles of the electrodes to few tens of nanometers, but also by surface modification and the synthesis of new multi-composite particles. It is the aim of this work to review the different approaches that have been successful to obtain Li-ion batteries with improved high-rate performance and to discuss how these results prefigure further improvement in the near future.

  15. Efficient spectral control and tuning of a high-power narrow-linewidth Yb-doped fiber laser using a transversely chirped volume Bragg grating.

    Science.gov (United States)

    Zeil, Peter; Pasiskevicius, Valdas; Laurell, Fredrik

    2013-02-25

    A transversely chirped volume Bragg grating (TCVBG) is used for flexible wavelength-tuning of a high-power (>100 W) tunable Yb-fiber laser oscillator. Continuous tuning over 2.5 THz of the narrow-band (13 GHz) signal was achieved by transversely translating the TCVBG during high-power operation without cavity realignment. The laser operated in a single polarization with a beam propagation factor (M(2)) of 1.2. Since the cavity losses remained constant, the high gain fiber laser exhibited excellent power stability (power and extending the tuning range while maintaining the power stability is discussed.

  16. Compact High Power Fiber Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of the proposed work is the development of a portable and efficient pulsed laser system for LIDAR and ranging applications, which make use of the latest...

  17. Spectral, spatial and temporal control of high-power diode lasers through nonlinear optical feedback

    NARCIS (Netherlands)

    van Voorst, P.D.

    2008-01-01

    A high-power diode laser offers multi-Watt output power from a small and efficient device, which makes them an interesting source for numerous applications. The spatial and spectral output however, are of reduced quality which limits the applicability. This limited quality is connected to the design

  18. A scalable-low cost architecture for high gain beamforming antennas

    KAUST Repository

    Bakr, Omar

    2010-10-01

    Many state-of-the-art wireless systems, such as long distance mesh networks and high bandwidth networks using mm-wave frequencies, require high gain antennas to overcome adverse channel conditions. These networks could be greatly aided by adaptive beamforming antenna arrays, which can significantly simplify the installation and maintenance costs (e.g., by enabling automatic beam alignment). However, building large, low cost beamforming arrays is very complicated. In this paper, we examine the main challenges presented by large arrays, starting from electromagnetic and antenna design and proceeding to the signal processing and algorithms domain. We propose 3-dimensional antenna structures and hybrid RF/digital radio architectures that can significantly reduce the complexity and improve the power efficiency of adaptive array systems. We also present signal processing techniques based on adaptive filtering methods that enhance the robustness of these architectures. Finally, we present computationally efficient vector quantization techniques that significantly improve the interference cancellation capabilities of analog beamforming architectures. © 2010 IEEE.

  19. A differential low-voltage high gain current-mode integrated RF receiver front-end

    Science.gov (United States)

    Chunhua, Wang; Minglin, Ma; Jingru, Sun; Sichun, Du; Xiaorong, Guo; Haizhen, He

    2011-02-01

    A differential low-voltage high gain current-mode integrated RF front end for an 802.11b WLAN is proposed. It contains a differential transconductance low noise amplifier (Gm-LNA) and a differential current-mode down converted mixer. The single terminal of the Gm-LNA contains just one MOS transistor, two capacitors and two inductors. The gate-source shunt capacitors, Cx1 and Cx2, can not only reduce the effects of gate-source Cgs on resonance frequency and input-matching impedance, but they also enable the gate inductance Lg1,2 to be selected at a very small value. The current-mode mixer is composed of four switched current mirrors. Adjusting the ratio of the drain channel sizes of the switched current mirrors can increase the gain of the mixer and accordingly increase the gain of RF receiver front-end. The RF front-end operates under 1 V supply voltage. The receiver RFIC was fabricated using a chartered 0.18 μm CMOS process. The integrated RF receiver front-end has a measured power conversion gain of 17.48 dB and an input referred third-order intercept point (IIP3) of -7.02 dBm. The total noise figure is 4.5 dB and the power is only 14 mW by post-simulations.

  20. Design of a high linearity and high gain accuracy analog baseband circuit for DAB receiver

    Science.gov (United States)

    Li, Ma; Zhigong, Wang; Jian, Xu; Yiqiang, Wu; Junliang, Wang; Mi, Tian; Jianping, Chen

    2015-02-01

    An analog baseband circuit of high linearity and high gain accuracy for a digital audio broadcasting receiver is implemented in a 0.18-μm RFCMOS process. The circuit comprises a 3rd-order active-RC complex filter (CF) and a programmable gain amplifier (PGA). An automatic tuning circuit is also designed to tune the CF's pass band. Instead of the class-A fully differential operational amplifier (FDOPA) adopted in the conventional CF and PGA design, a class-AB FDOPA is specially employed in this circuit to achieve a higher linearity and gain accuracy for its large current swing capability with lower static current consumption. In the PGA circuit, a novel DC offset cancellation technique based on the MOS resistor is introduced to reduce the settling time significantly. A reformative switching network is proposed, which can eliminate the switch resistor's influence on the gain accuracy of the PGA. The measurement result shows the gain range of the circuit is 10-50 dB with a 1-dB step size, and the gain accuracy is less than ±0.3 dB. The OIP3 is 23.3 dBm at the gain of 10 dB. Simulation results show that the settling time is reduced from 100 to 1 ms. The image band rejection is about 40 dB. It only draws 4.5 mA current from a 1.8 V supply voltage.

  1. To kill a kangaroo: understanding the decision to pursue high-risk/high-gain resources.

    Science.gov (United States)

    Jones, James Holland; Bird, Rebecca Bliege; Bird, Douglas W

    2013-09-22

    In this paper, we attempt to understand hunter-gatherer foraging decisions about prey that vary in both the mean and variance of energy return using an expected utility framework. We show that for skewed distributions of energetic returns, the standard linear variance discounting (LVD) model for risk-sensitive foraging can produce quite misleading results. In addition to creating difficulties for the LVD model, the skewed distributions characteristic of hunting returns create challenges for estimating probability distribution functions required for expected utility. We present a solution using a two-component finite mixture model for foraging returns. We then use detailed foraging returns data based on focal follows of individual hunters in Western Australia hunting for high-risk/high-gain (hill kangaroo) and relatively low-risk/low-gain (sand monitor) prey. Using probability densities for the two resources estimated from the mixture models, combined with theoretically sensible utility curves characterized by diminishing marginal utility for the highest returns, we find that the expected utility of the sand monitors greatly exceeds that of kangaroos despite the fact that the mean energy return for kangaroos is nearly twice as large as that for sand monitors. We conclude that the decision to hunt hill kangaroos does not arise simply as part of an energetic utility-maximization strategy and that additional social, political or symbolic benefits must accrue to hunters of this highly variable prey.

  2. MULTIPULSE - high resolution and high power in one TDEM system

    Science.gov (United States)

    Chen, Tianyou; Hodges, Greg; Miles, Philip

    2015-09-01

    An airborne time domain electromagnetic (TEM) system with high resolution and great depth of exploration is desired for geological mapping as well as for mineral exploration. The MULTIPULSE technology enables an airborne TEM system to transmit a high power pulse (a half-sine, for instance) and one or multiple low power pulse(s) (trapezoid or square) within a half-cycle. The high power pulse ensures good depth of exploration and the low power pulse allows a fast transmitter current turn off and earlier off-time measurement thus providing higher frequency signals, which allows higher near-surface resolution and better sensitivity to weak conductors. The power spectrum of the MULTIPULSE waveform comprising a half-sine and a trapezoid pulse clearly shows increased power in the higher frequency range (> ~2.3 kHz) compared to that of a single half-sine waveform. The addition of the low power trapezoid pulse extends the range of the sensitivity 10-fold towards the weak conductors, expanding the geological conductivity range of a system and increasing the scope of its applications. The MULTIPULSE technology can be applied to standard single-pulse airborne TEM systems on both helicopter and fixed-wing. We field tested the HELITEM MULTIPULSE system over a wire-loop in Iroquois Falls, demonstrating the different sensitivity of the high and low power pulses to the overburden and the wire-loop. We also tested both HELITEM and GEOTEM MULTIPULSE systems over a layered oil sand geologic setting in Fort McMurray, Alberta, Canada. The results show comparable shallow geologic resolution of the MULTIPULSE to that of the RESOLVE system while maintaining superior depth of exploration, confirming the increased geological conductivity range of a system employing MULTIPULSE compared to the standard single-pulse systems.

  3. Reduced filamentation in high power semiconductor lasers

    DEFF Research Database (Denmark)

    Skovgaard, Peter M. W.; McInerney, John; O'Brien, Peter

    1999-01-01

    High brightness semiconductor lasers have applications in fields ranging from material processing to medicine. The main difficulty associated with high brightness is that high optical power densities cause damage to the laser facet and thus require large apertures. This, in turn, results in spatio....... Experimentally, we generate transverse current profiles by using standard lithography to define a digitated contact pad. Experimental results confirm that the current density is significantly altered and show completely filamentation-free operation up to 34 times threshold....

  4. Terahertz radiation source using a high-power industrial electron linear accelerator

    Science.gov (United States)

    Kalkal, Yashvir; Kumar, Vinit

    2017-04-01

    High-power (˜ 100 kW) industrial electron linear accelerators (linacs) are used for irradiations, e.g., for pasteurization of food products, disinfection of medical waste, etc. We propose that high-power electron beam from such an industrial linac can first pass through an undulator to generate useful terahertz (THz) radiation, and the spent electron beam coming out of the undulator can still be used for the intended industrial applications. This will enhance the utilization of a high-power industrial linac. We have performed calculation of spontaneous emission in the undulator to show that for typical parameters, continuous terahertz radiation having power of the order of μW can be produced, which may be useful for many scientific applications such as multispectral imaging of biological samples, chemical samples etc.

  5. Linear and nonlinear filters under high power microwave conditions

    Directory of Open Access Journals (Sweden)

    F. Brauer

    2009-05-01

    Full Text Available The development of protection circuits against a variety of electromagnetic disturbances is important to assure the immunity of an electronic system. In this paper the behavior of linear and nonlinear filters is measured and simulated with high power microwave (HPM signals to achieve a comprehensive protection against different high power electromagnetic (HPEM threats.

  6. Improved cutting performance in high power laser cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    2003-01-01

    Recent results in high power laser cutting especially with focus on cutting of mild grade steel types for shipbuilding are described.......Recent results in high power laser cutting especially with focus on cutting of mild grade steel types for shipbuilding are described....

  7. A differential low-voltage high gain current-mode integrated RF receiver front-end

    Energy Technology Data Exchange (ETDEWEB)

    Wang Chunhua; Ma Minglin; Sun Jingru; Du Sichun; Guo Xiaorong; He Haizhen, E-mail: wch1227164@sina.com [School of Information Science and Technology, Hunan University, Changsha 410082 (China)

    2011-02-15

    A differential low-voltage high gain current-mode integrated RF front end for an 802.11b WLAN is proposed. It contains a differential transconductance low noise amplifier (G{sub m}-LNA) and a differential current-mode down converted mixer. The single terminal of the G{sub m}-LNA contains just one MOS transistor, two capacitors and two inductors. The gate-source shunt capacitors, C{sub x1} and C{sub x2}, can not only reduce the effects of gate-source C{sub gs} on resonance frequency and input-matching impedance, but they also enable the gate inductance L{sub g1,2} to be selected at a very small value. The current-mode mixer is composed of four switched current mirrors. Adjusting the ratio of the drain channel sizes of the switched current mirrors can increase the gain of the mixer and accordingly increase the gain of RF receiver front-end. The RF front-end operates under 1 V supply voltage. The receiver RFIC was fabricated using a chartered 0.18 {mu}m CMOS process. The integrated RF receiver front-end has a measured power conversion gain of 17.48 dB and an input referred third-order intercept point (IIP3) of -7.02 dBm. The total noise figure is 4.5 dB and the power is only 14 mW by post-simulations. (semiconductor integrated circuits)

  8. Beam Delivery Systems For High Power Lasers

    Science.gov (United States)

    Hohberg, G.

    1986-10-01

    For materials processing with lasers, beam delivery systems are necessary for directing the radiation from the laser head to the working point on the workpiece. The more new fields of application are assumed by the laser, the greater the need for beam delivery systems which have been appropriately designed to meet the requirements of the task to be performed. Depending on the task on hand the appropriate design may be a fixed pipe with a focussing lens at its end or a six-axis articulated arm. This paper will describe the design principles and their optical and mechanical properties. The discussion of the advantages and disadvantages may be of some help in choosing an adequate delivery system.

  9. High-power laser source evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Back, C.A.; Decker, C.D.; Dipeso, G.J.; Gerassimenko, M.; Managan, R.A.; Serduke, F.J.D.; Simonson, G.F.; Suter, L.J.

    1997-07-01

    This document reports progress in these areas: EXPERIMENTAL RESULTS FROM NOVA: TAMPED XENON UNDERDENSE X-RAY EMITTERS; MODELING MULTI-KEV RADIATION PRODUCTION OF XENON-FILLED BERYLLIUM CANS; MAPPING A CALCULATION FROM LASNEX TO CALE; HOT X RAYS FROM SEEDED NIF CAPSULES; HOHLRAUM DEBRIS MEASUREMENTS AT NOVA; FOAM AND STRUCTURAL RESPONSE CALCULATIONS FOR NIF NEUTRON EXPOSURE SAMPLE CASE ASSEMBLY DESIGN; NON-IGNITION X-RAY SOURCE FLUENCE-AREA PRODUCTS FOR NUCLEAR EFFECTS TESTING ON NIF. Also appended are reprints of two papers. The first is on the subject of ``X-Ray Production in Laser-Heated Xe Gas Targets.`` The second is on ``Efficient Production and Applications of 2- to 10-keV X Rays by Laser-Heated Underdense Radiators.``

  10. Dynamic Sliding Mode Evolution PWM Controller for a Novel High-Gain Interleaved DC-DC Converter in PV System

    Directory of Open Access Journals (Sweden)

    Taizhou Bei

    2014-01-01

    Full Text Available Considering the disadvantages of the traditional high-gain DC-DC converter such as big size, high voltage stress of switches, and large input current ripple, a novel high-gain interleaved boost converter with coupled-inductor and switched-capacitor was proposed correspondingly and the operation principle together with the steady-state analysis of this converter was also described. Besides, a new control approach-dynamic sliding mode evolution PWM controller (DSME PWM for the novel topological converter based on both dynamic evolution and sliding mode control was also presented. From the simulation results and experimental validation the proposed converter can fulfill high-gain boost, low ripple of both the input current and the output voltage. Furthermore, MPPT technique can be also achieved in a short time by simulation. The efficiency and stability of the converter proposed in this paper can be improved.

  11. High Power Zero-Voltage and Zero-Current Switching DC-DC Converters

    Directory of Open Access Journals (Sweden)

    Jaroslav Dudrik

    2005-01-01

    Full Text Available The paper presents principles and properties of the soft switching PWM DC-DC converters. The attention is focused mainly on high power applications and thus the full-bridge inverters are used in DC-DC converters. Considerations are also given to the control methods and principles of the switching and conduction losses reduction.

  12. Assessment methodology of counter-personnel high power electromagnetic millimeter wave effects

    NARCIS (Netherlands)

    Valente, F.; Horst, M.J. van der; Paulissen, J.J.M.; Zwamborn, A.P.M.; Toet, A.

    2013-01-01

    The group of NLW that arguably offers the largest amount of useful applications are based on high power electromagnetic millimetre wave technology. This group is often referred to as ‘Active Denial Systems’ (ADS), since they are primarily aimed at deterring and dispersing people out of an area. The

  13. Low-loss electron beam transport in a high-power, electrostatic free-electron maser

    NARCIS (Netherlands)

    Valentini, M.; van der Geer, C. A. J.; Verhoeven, A. G. A.; van der Wiel, M. J.; Urbanus, W. H.

    1997-01-01

    At the FOM Institute for Plasma Physics ''Rijnhuizen'', The Netherlands, the commissioning of a high-power, electrostatic free-electron maser is in progress. The design target is the generation of 1 MW microwave power in the frequency range 130-260 GHz. The foreseen application

  14. Two new families of high-gain dc-dc power electronic converters for dc-microgrids

    Science.gov (United States)

    Prabhala, Venkata Anand Kishore

    Distributing the electric power in dc form is an appealing solution in many applications such as telecommunications, data centers, commercial buildings, and microgrids. A high gain dc-dc power electronic converter can be used to individually link low-voltage elements such as solar panels, fuel cells, and batteries to the dc voltage bus which is usually 400 volts. This way, it is not required to put such elements in a series string to build up their voltages. Consequently, each element can function at it optimal operating point regardless of the other elements in the system. In this dissertation, first a comparative study of dc microgrid architectures and their advantages over their ac counterparts is presented. Voltage level selection of dc distribution systems is discussed from the cost, reliability, efficiency, and safety standpoints. Next, a new family of non-isolated high-voltage-gain dc-dc power electronic converters with unidirectional power flow is introduced. This family of converters benefits from a low voltage stress across its switches. The proposed topologies are versatile as they can be utilized as single-input or double-input power converters. In either case, they draw continuous currents from their sources. Lastly, a bidirectional high-voltage-gain dc-dc power electronic converter is proposed. This converter is comprised of a bidirectional boost converter which feeds a switched-capacitor architecture. The switched-capacitor stage suggested here has several advantages over the existing approaches. For example, it benefits from a higher voltage gain while it uses less number of capacitors. The proposed converters are highly efficient and modular. The operating modes, dc voltage gain, and design procedure for each converter are discussed in details. Hardware prototypes have been developed in the lab. The results obtained from the hardware agree with those of the simulation models.

  15. High-Power Fiber Lasers Using Photonic Band Gap Materials

    Science.gov (United States)

    DiDomenico, Leo; Dowling, Jonathan

    2005-01-01

    High-power fiber lasers (HPFLs) would be made from photonic band gap (PBG) materials, according to the proposal. Such lasers would be scalable in the sense that a large number of fiber lasers could be arranged in an array or bundle and then operated in phase-locked condition to generate a superposition and highly directed high-power laser beam. It has been estimated that an average power level as high as 1,000 W per fiber could be achieved in such an array. Examples of potential applications for the proposed single-fiber lasers include welding and laser surgery. Additionally, the bundled fibers have applications in beaming power through free space for autonomous vehicles, laser weapons, free-space communications, and inducing photochemical reactions in large-scale industrial processes. The proposal has been inspired in part by recent improvements in the capabilities of single-mode fiber amplifiers and lasers to produce continuous high-power radiation. In particular, it has been found that the average output power of a single strand of a fiber laser can be increased by suitably changing the doping profile of active ions in its gain medium to optimize the spatial overlap of the electromagnetic field with the distribution of active ions. Such optimization minimizes pump power losses and increases the gain in the fiber laser system. The proposal would expand the basic concept of this type of optimization to incorporate exploitation of the properties (including, in some cases, nonlinearities) of PBG materials to obtain power levels and efficiencies higher than are now possible. Another element of the proposal is to enable pumping by concentrated sunlight. Somewhat more specifically, the proposal calls for exploitation of the properties of PBG materials to overcome a number of stubborn adverse phenomena that have impeded prior efforts to perfect HPFLs. The most relevant of those phenomena is amplified spontaneous emission (ASE), which causes saturation of gain and power

  16. Filling the THz Gap - High Power Sources and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Gwyn Williams

    2006-02-01

    Electromagnetic waves centered at a frequency of 1 THz lie between photonics on the one hand and electronics on the other, and are very hard to generate and detect. However, since the THz part of the spectrum is energetically equivalent to many important physical, chemical and biological processes including superconducting gaps and protein dynamical processes, it is of great interest to facilitate experimental research in this region. This has stimulated major steps in the past decade for filling this gap in the usable spectrum. In this review paper we describe the evolution of a new generation of sources that boost the average power available in the THz region by more than a million-fold, making this region routinely accessible for the first time. This is achieved using two enhancement factors, namely relativistic electrons and super-radiance. We will also point to the scientific potential for discovery that is now enabled in this region.

  17. Generation and application of high power flattened Gaussian beams

    CSIR Research Space (South Africa)

    Forbes, A

    2009-07-01

    Full Text Available Presented at the 2009 South African Institute of Physics Annual Conference University of KwaZulu-Natal Durban, South Africa 6-10 July 2009 Flattened Gaussian Beams (FGBs) change shape as they propagation ( ) ( ) ( ) m p nm n n p n nn n m p...OC n DOE        −= ∫∞+ 2 0 21 2 exp)( 2 exp)exp()/(),( ρρρ )],([ * Luphase DOEDOE ρφ = DOE DOE DOE u u t * = Proc. SPIE 7062, 706219-1, 2008 Design of a mirror to produce an N = 10 FGB 0 2 4 6 8 10 12...

  18. Fundamentals of Metamaterials for High-power RF Applications

    Science.gov (United States)

    2012-02-08

    waveguide traveling wave tube ( TWT ). In the case of the Cerenkov maser, the metamaterials act to produce, within a given frequency band, nearly the...same characteristics as a conventional dielectric, but with an all-metallic structure. In the case of the TWT , the metamaterial introduces new

  19. Solar Pumped High Power Solid State Laser for Space Applications

    Science.gov (United States)

    Fork, Richard L.; Laycock, Rustin L.; Green, Jason J. A.; Walker, Wesley W.; Cole, Spencer T.; Frederick, Kevin B.; Phillips, Dane J.

    2004-01-01

    Highly coherent laser light provides a nearly optimal means of transmitting power in space. The simplest most direct means of converting sunlight to coherent laser light is a solar pumped laser oscillator. A key need for broadly useful space solar power is a robust solid state laser oscillator capable of operating efficiently in near Earth space at output powers in the multi hundred kilowatt range. The principal challenges in realizing such solar pumped laser oscillators are: (1) the need to remove heat from the solid state laser material without introducing unacceptable thermal shock, thermal lensing, or thermal stress induced birefringence to a degree that improves on current removal rates by several orders of magnitude and (2) to introduce sunlight at an effective concentration (kW/sq cm of laser cross sectional area) that is several orders of magnitude higher than currently available while tolerating a pointing error of the spacecraft of several degrees. We discuss strategies for addressing these challenges. The need to remove the high densities of heat, e.g., 30 kW/cu cm, while keeping the thermal shock, thermal lensing and thermal stress induced birefringence loss sufficiently low is addressed in terms of a novel use of diamond integrated with the laser material, such as Ti:sapphire in a manner such that the waste heat is removed from the laser medium in an axial direction and in the diamond in a radial direction. We discuss means for concentrating sunlight to an effective areal density of the order of 30 kW/sq cm. The method integrates conventional imaging optics, non-imaging optics and nonlinear optics. In effect we use a method that combines some of the methods of optical pumping solid state materials and optical fiber, but also address laser media having areas sufficiently large, e.g., 1 cm diameter to handle the multi-hundred kilowatt level powers needed for space solar power.

  20. Applications of high power lasers in the battlefield

    Science.gov (United States)

    Kalisky, Yehoshua

    2009-09-01

    Laser weapon is currently considered as tactical as well as strategic beam weapons, and is considered as a part of a general layered defense system against ballistic missiles and short-range rockets. This kind of weapon can disable or destroy military targets or incoming objects used by small groups of terrorists or countries, at the speed of light. Laser weapon is effective at long or short distances, owing to beam's unique characteristics such as narrow bandwidth, high brightness, coherent both in time and space, and it travels at the speed of light. Unlike kinetic weapon, laser weapon converts the energy stored in an electromagnetic laser beam into a large amount of heat aimed on a small area spot at the skin of the missile, usually close to the liquid fuel storage tank, warhead case or engine area, following by a temperature increase and finally-catastrophic failure by material ablation or melt. The usefulness of laser light as a weapon has been studied for decades but only in recent years became feasible. There are two types of lasers being used: gas lasers and solid state lasers, including fiber lasers. All these types of lasers will be discussed below.

  1. A Lemon Cell Battery for High-Power Applications

    Science.gov (United States)

    Muske, Kenneth R.; Nigh, Christopher W.; Weinstein, Randy D.

    2007-01-01

    The use of lemon cell battery to run an electric DC motor is demonstrated for chemistry students. This demonstration aids the students in understanding principles behind the design and construction of the lemon cell battery and principles governing the electric DC motor and other basic principles.

  2. High Power Optically Pumped Semiconductor Lasers for Sodium Guidestar Applications

    Science.gov (United States)

    Hackett, Shawn

    2016-09-01

    Optically pumped semiconductor lasers (OPSLs) are shown to provide a much more compact and less expensive source for illumination of the sodium layer of the mesosphere for use as a sodium laser guidestar via single and two photon excitation schemes. This represents a revolution in laser guidestar technology as the cost, size, and power requirements for a laser guidestar system are shown to have been decreased by an order of magnitude with guidestar performance shown to be similar to previous sources. Sodium laser guidestar sources for broadband simultaneous illumination of multiple lines are developed and simulated. Simulations are then compared to actual returns for multi-line sodium laser guidestars. The simultaneous multi-line laser guidestar is shown to be superior to the single line laser guidestar for equal output powers both via modeling and via on sky returns performed at Starfire Optical Range (SOR) with a combination of a legacy narrowband laser guidestars and a broadband OPSL guidestar. The multi-line OPSL guidestars are shown to provide the first continuous wave source for use as a polychromatic laser guidestar (PLGS) to correct for tip and tilt aberrations. Different methods for utilization of the PLGS are simulated and compared showing that the OPSL sources developed are suitable for use as a CW PLGS to correct for tip and tilt with current generation telescopes and adaptive optics systems. Wave optics and Bloch equation simulations are then developed and performed to determine the utility and optimal setup for LGS and PLGS systems which prove OPSL's utility as the next generation of sodium laser guidestars.

  3. The Study on the Reliability of High Power LED Streetlights

    Science.gov (United States)

    Dong-Ge, Yao; Jian-Xin, Chen

    2011-02-01

    This paper was about a reliable research on high-power LED lighting. Based on the samples of the self-developed high-power LED streetlights, an electrical stress ageing test was carried out and thermocouple method was used in the temperature test. The ageing test showed that the initial flux reduction was mainly due to the absorption of the light lamp or the block by some parts of the lighting. And the late light decling was mainly caused by the decay of the high-power LED light source itself. Some suggestions on improving the design of streetlights will be given according to my research.

  4. Verification of the Solar Dynamics Observatory High Gain Antenna Pointing Algorithm Using Flight Data

    Science.gov (United States)

    Bourkland, Kristin L.; Liu, Kuo-Chia

    2011-01-01

    The Solar Dynamics Observatory (SDO) is a NASA spacecraft designed to study the Sun. It was launched on February 11, 2010 into a geosynchronous orbit, and uses a suite of attitude sensors and actuators to finely point the spacecraft at the Sun. SDO has three science instruments: the Atmospheric Imaging Assembly (AIA), the Helioseismic and Magnetic Imager (HMI), and the Extreme Ultraviolet Variability Experiment (EVE). SDO uses two High Gain Antennas (HGAs) to send science data to a dedicated ground station in White Sands, New Mexico. In order to meet the science data capture budget, the HGAs must be able to transmit data to the ground for a very large percentage of the time. Each HGA is a dual-axis antenna driven by stepper motors. Both antennas transmit data at all times, but only a single antenna is required in order to meet the transmission rate requirement. For portions of the year, one antenna or the other has an unobstructed view of the White Sands ground station. During other periods, however, the view from both antennas to the Earth is blocked for different portions of the day. During these times of blockage, the two HGAs take turns pointing to White Sands, with the other antenna pointing out to space. The HGAs handover White Sands transmission responsibilities to the unblocked antenna. There are two handover seasons per year, each lasting about 72 days, where the antennas hand off control every twelve hours. The non-tracking antenna slews back to the ground station by following a ground commanded trajectory and arrives approximately 5 minutes before the formerly tracking antenna slews away to point out into space. The SDO Attitude Control System (ACS) runs at 5 Hz, and the HGA Gimbal Control Electronics (GCE) run at 200 Hz. There are 40 opportunities for the gimbals to step each ACS cycle, with a hardware limitation of no more than one step every three GCE cycles. The ACS calculates the desired gimbal motion for tracking the ground station or for slewing

  5. Progress in high-power continuous-wave quantum cascade lasers [Invited].

    Science.gov (United States)

    Figueiredo, Pedro; Suttinger, Matthew; Go, Rowel; Tsvid, Eugene; Patel, C Kumar N; Lyakh, Arkadiy

    2017-11-01

    Multi-watt continuous-wave room temperature operation with efficiency exceeding 10% has been demonstrated for quantum cascade lasers essentially in the entire mid-wave and long-wave infrared spectral regions. Along with interband cascade lasers, these devices are the only room-temperature lasers that directly convert electrical power into mid- and long-infrared optical power. In this paper, we review the progress in high-power quantum cascade lasers made over the last 10 years. Specifically, an overview of the most important active region, waveguide, and thermal design techniques is presented, and various aspects of die packaging for high-power applications are discussed. Prospects of power scaling with lateral device dimensions for reaching optical power level in the range from 10 W to 20 W are also analyzed. Finally, coherent and spectral beam-combining techniques for very high-power infrared platforms are discussed.

  6. High-Power Solar Electric Propulsion for Future NASA Missions

    Science.gov (United States)

    Manzella, David; Hack, Kurt

    2014-01-01

    NASA has sought to utilize high-power solar electric propulsion as means of improving the affordability of in-space transportation for almost 50 years. Early efforts focused on 25 to 50 kilowatt systems that could be used with the Space Shuttle, while later efforts focused on systems nearly an order of magnitude higher power that could be used with heavy lift launch vehicles. These efforts never left the concept development phase in part because the technology required was not sufficiently mature. Since 2012 the NASA Space Technology Mission Directorate has had a coordinated plan to mature the requisite solar array and electric propulsion technology needed to implement a 30 to 50 kilowatt solar electric propulsion technology demonstration mission. Multiple solar electric propulsion technology demonstration mission concepts have been developed based on these maturing technologies with recent efforts focusing on an Asteroid Redirect Robotic Mission. If implemented, the Asteroid Redirect Vehicle will form the basis for a capability that can be cost-effectively evolved over time to provide solar electric propulsion transportation for a range of follow-on mission applications at power levels in excess of 100 kilowatts.

  7. Vacuum Window Design for High-Power Lasers

    CERN Document Server

    Shaftan, T V

    2005-01-01

    One of the problems in the high-power lasers design is in outcoupling of a powerful laser beam out of a vacuum volume into atmosphere. Usually the laser device is located inside a vacuum tank. The laser radiation is transported to the outside world through the transparent vacuum window. While considered transparent, some of the light passing through the glass is absorbed and converted to heat. For most applications, these properties are academic curiosities; however, in multi-kilowatt lasers, the heat becomes significant and can lead to a failure. The absorbed power can result in thermal stress, reduction of light transmission and, consequently, window damage. Modern optical technology has developed different types of glass (Silica, BK7, diamond, etc.) that have high thermal conductivity and damage threshold. However, for kilo- and megawatt lasers the issue still remains open. In this paper we present a solution that may relieve the heat load on the output window. We discuss advantages and issues of this part...

  8. Glycol-Substitute for High Power RF Water Loads

    CERN Document Server

    Ebert, Michael

    2005-01-01

    In water loads for high power rf applications, power is dissipated directly into the coolant. Loads for frequencies below approx. 1GHz are ordinarily using an ethylene glycol-water mixture as coolant. The rf systems at DESY utilize about 100 glycol water loads with powers ranging up to 600kW. Due to the increased ecological awareness, the use of glycol is now considered to be problematic. In EU it is forbidden to discharge glycol into the waste water system. In case of cooling system leakages one has to make sure that no glycol is lost. Since it is nearly impossible to avoid any glycol loss in large rf systems, a glycol-substitute was searched for and found. The found sodium-molybdate based substitute is actually a additive for corrosion protection in water systems. Sodium-molybdate is ecologically harmless; for instance, it is also used as fertilizer in agriculture. A homoeopathic dose of 0.4% mixed into deionised water gives better rf absorption characteristics than a 30% glycol mixture. The rf coolant feat...

  9. A safe, high-power-density lithium battery

    Science.gov (United States)

    Walsh, F.

    1985-03-01

    The Li/SOCl2 battery has received attention because of its high theoretical energy/power density. However, practical Li/SOCl2 cells have not provided the desired power density and have suffered from concerns with cell safety on discharge. In previous work, ECO has shown that the use of a TAA-type catalyst significantly improves the safety of the Li/S0Cl2 cell at high rate. The objective of this Phase 1 program was to determine whether a stacked disk electrode configuration with TAA-catalyzed cathodes would meet a high power-density design goal. Under the program, the effects of cathode thickness, preparation pressure, electrolyte gap and solute concentration on stacked-electrode cell performance and capacity were measured. The results of the Phase 1 program included the demonstration of stacked-electrode cell performance and capacity at levels suitable to meet a design goal of 400 W/kg with high energy density. Further work in a Phase 2 program will be required to demonstrate in laser-sealed fully-packaged cells that the results of Phase 1 can be practically applied to provide a safe high-rate, energy-dense power source for military applications.

  10. Adaptive metal mirror for high-power CO2 lasers

    Science.gov (United States)

    Jarosch, Uwe-Klaus

    1996-08-01

    Spherical mirrors with a variable radius of curvature are used inside laser resonators as well as in the beam path between the laser and the workpiece. Commercially-available systems use piezoelectric actuators, or the pressure of the coolant, to deform the mirror surface. In both cases, the actuator and the cooling system influence each other. This interaction is avoided through the integration of the cooling system with the flexible mirror membrane. A multi- channel design leads to an optimized cooling effect, which is necessary for high power applications. The contour of the variable metal mirror depends on the mounting between the membrane and the mirror body and on the distribution of forces. Four cases of deformation can be distinguished for a circular elastic membrane. The realization of an adaptive metal mirror requires a technical compromise to be made. A mechanical construction is presented which combines an elastic hinge with the inlet and outlet of the coolant. For the deformation of the mirror membranes two actuators with different character of deformation are used. The superposition of the two deformations results in smaller deviations from the spherical surface shape than can be achieved using a single actuator. DC proportional magnets have been introduced as cheap and rigid actuators. The use of this adaptive mirror, either in a low pressure atmosphere of a gas laser resonator, or in an extra-cavity beam path is made possible through the use of a ventilation system.

  11. High Power Uplink Amplifier for Deep Space Communications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Critical to the success of delivering on the promise of deep space optical communications is the creation of a stable and reliable high power multichannel optical...

  12. High Power Room Temperature Terahertz Local Oscillator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to build a high-power, room temperature compact continuous wave terahertz local oscillator for driving heterodyne receivers in the 1-5 THz frequency...

  13. High power laser workover and completion tools and systems

    Science.gov (United States)

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2014-10-28

    Workover and completion systems, devices and methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena. Systems and devices for the laser workover and completion of a borehole in the earth. These systems and devices can deliver high power laser energy down a deep borehole, while maintaining the high power to perform laser workover and completion operations in such boreholes deep within the earth.

  14. Apparatus for advancing a wellbore using high power laser energy

    Science.gov (United States)

    Zediker, Mark S.; Land, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Koblick, Yeshaya; Moxley, Joel F.

    2014-09-02

    Delivering high power laser energy to form a borehole deep into the earth using laser energy. Down hole laser tools, laser systems and laser delivery techniques for advancement, workover and completion activities. A laser bottom hole assembly (LBHA) for the delivery of high power laser energy to the surfaces of a borehole, which assembly may have laser optics, a fluid path for debris removal and a mechanical means to remove earth.

  15. High power laser downhole cutting tools and systems

    Science.gov (United States)

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2015-01-20

    Downhole cutting systems, devices and methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena. Systems and devices for the laser cutting operations within a borehole in the earth. These systems and devices can deliver high power laser energy down a deep borehole, while maintaining the high power to perform cutting operations in such boreholes deep within the earth.

  16. Thermally induced nonlinear mode coupling in high power fiber amplifiers

    DEFF Research Database (Denmark)

    Johansen, Mette Marie; Hansen, Kristian Rymann; Alkeskjold, Thomas T.

    2013-01-01

    Thermally induced nonlinear mode coupling leads to transverse mode instability (TMI) in high power fiber amplifiers. A numerical model including altering mode profiles from thermal effects and waveguide perturbations predicts a TMI threshold of ~200W.......Thermally induced nonlinear mode coupling leads to transverse mode instability (TMI) in high power fiber amplifiers. A numerical model including altering mode profiles from thermal effects and waveguide perturbations predicts a TMI threshold of ~200W....

  17. High-power IR laser in SMT package

    Science.gov (United States)

    Pritsch, Benedikt; Behringer, Martin; Arzberger, Markus; Wiesner, Christoph; Fehse, Robin; Heerlein, Jörg; Maric, Josip; Giziewicz, Wojciech

    2009-02-01

    Laser dies in an optical power range of 1-3 Watts are widely assembled in popular TO- packages. TO-packages suffer from high thermal resistance and limited output power. Bad thermal contact between circuit boards and TO-devices can cause overheating of laser chips, significantly reducing the operating life time. We developed a compact high heat-load SMT package for an optical power up to 7 Watts in CW operation with good life time results. The new package for high power laser chips combines highly efficient heat dissipation with Surface-mount technology. A Direct-Bonded-Copper (DBC) substrate acts as a base plate for the laser chip and heat sink. The attached frame is used for electrical contacting and acts as beam reflector where the laser light is reflected at a 45° mirror. In the application the DBC base plate of the SMT-Laser is directly soldered to a Metal-Core-PCB by reflow soldering. The overall thermal resistance from laser chip to the bottom of a MC-PCB was measured as low as 2.5 K/W. The device placement process can be operated by modern high-speed mounting equipment. The direct link between device and MC-PCB allows CW laser operation up to 6-7 watts at wavelengths of 808nm to 940nm without facing any overheating symptom like thermal roll over. The device is suitable for CW and QCW operation. In pulsed operation short rise and fall times of <2ns have been demonstrated. New application fields like infrared illumination for sensing purposes in the automotive industry and 3D imaging systems could be opened by this new technology.

  18. Multi-focus beam shaping of high power multimode lasers

    Science.gov (United States)

    Laskin, Alexander; Volpp, Joerg; Laskin, Vadim; Ostrun, Aleksei

    2017-08-01

    Beam shaping of powerful multimode fiber lasers, fiber-coupled solid-state and diode lasers is of great importance for improvements of industrial laser applications. Welding, cladding with millimetre scale working spots benefit from "inverseGauss" intensity profiles; performance of thick metal sheet cutting, deep penetration welding can be enhanced when distributing the laser energy along the optical axis as more efficient usage of laser energy, higher edge quality and reduction of the heat affected zone can be achieved. Building of beam shaping optics for multimode lasers encounters physical limitations due to the low beam spatial coherence of multimode fiber-coupled lasers resulting in big Beam Parameter Products (BPP) or M² values. The laser radiation emerging from a multimode fiber presents a mixture of wavefronts. The fiber end can be considered as a light source which optical properties are intermediate between a Lambertian source and a single mode laser beam. Imaging of the fiber end, using a collimator and a focusing objective, is a robust and widely used beam delivery approach. Beam shaping solutions are suggested in form of optics combining fiber end imaging and geometrical separation of focused spots either perpendicular to or along the optical axis. Thus, energy of high power lasers is distributed among multiple foci. In order to provide reliable operation with multi-kW lasers and avoid damages the optics are designed as refractive elements with smooth optical surfaces. The paper presents descriptions of multi-focus optics as well as examples of intensity profile measurements of beam caustics and application results.

  19. Atmospheric propagation of high power laser radiation at different weather conditions

    OpenAIRE

    Pargmann, Carsten; Hall, Thomas; Duschek, Frank; Handke, Jürgen

    2016-01-01

    Applications based on the propagation of high power laser radiation through the atmosphere are limited in range and effect, due to weather dependent beam wandering, beam deterioration, and scattering processes. Security and defense related application examples are countermeasures against hostile projectiles and the powering of satellites and aircrafts. For an examination of the correlations between weather condition and laser beam characteristics DLR operates at Lampoldshausen a 130 m long fr...

  20. Development of High Power Lasers for Materials Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Hackel, L A

    2003-04-11

    The Lawrence Livermore National Laboratory (LLNL) has a long history of developing high power lasers for use in basic science and applications. The Laser Science and Technology Program (LS&T) at LLNL supports advanced lasers and optics development both for the National Ignition Facility (NIF) as well as for high power lasers and optics technology for a broader range of government, military and industrial applications. The NIF laser is currently under construction with the first of the 192 beamlines being activated. When finished NIF will have an output energy of 2 MJ at 351 nm. This system will be used for studies of high energy density physics, equation of state and inertial confinement fusion. It is now generally acknowledged that the future of laser missile defense lies with solid state lasers. The leading laser technology for theater missile defense is under development within the LS&T and funded by the US Army SMDC. This high average power technology is based on a solid state laser operated in a heat capacity mode. In the concept the heat producing lasing cycle is separated in time from the cooling cycle thus reducing thermal gradients and allowing significantly greater average output power. Under the current program, an LLNL developed laser has achieved a record setting 13 kW of average power in 20 second duration bursts. We have also performed target lethality experiments showing a previously unrecognized advantage of a pulsed laser format. The LLNL work is now focused on achieving improved output beam quality and in developing a 100 kW output with diode pumping of a large aperture crystal gain medium on a compact mobile platform. The Short Pulse Laser Group of LS&T has been developing high power short pulse laser systems for a number of applications. Of great importance is petawatt (10{sup 12} Watt) and greater power output to support experiments on the NIF. We are developing a system of 5 M class output and 5 to 10 ps pulse duration for generating intense

  1. Novel LY Converter Topologies for High Gain Transfer Ratio - A New Breed of XY Family

    DEFF Research Database (Denmark)

    Bhaskar, M.S.; Padmanaban, S.; Kulkarni, R.

    2016-01-01

    New LY converter topologies of DC-DC XY family for renewable energy applications are articulated in this paper. Four LY topologies are presented in this paper and the proposed topologies provide an operative solution for renewable energy applications which requires a very high inverting voltage...... consistently showed good conformity with theoretical analysis and also validates the functionality of the proposed LY converter topologies of the XY converter family....

  2. Investigation of a metallic photonic crystal high power microwave mode converter

    Directory of Open Access Journals (Sweden)

    Dong Wang

    2015-02-01

    Full Text Available It is demonstrated that an L band metallic photonic crystal TEM-TE11 mode converter is suitable for narrow band high power microwave application. The proposed mode converter is realized by partially filling metallic photonic crystals along azimuthal direction in a coaxial transmission line for phase-shifting. A three rows structure is designed and simulated by commercial software CST Microwave Studio. Simulation results show that its conversion efficiency is 99% at the center frequency 1.58 GHz. Over the frequency range of 1.56-1.625 GHz, the conversion efficiency exceeds 90 %, with a corresponding bandwidth of 4.1 %. This mode converter has a gigawatt level power handling capability which is suitable for narrow band high power microwave application. Using magnetically insulated transmission line oscillator(MILO as a high power microwave source, particle-in-cell simulation is carried out to test the performance of the mode converter. The expected TE11 mode microwave output is obtained and the MILO works well. Mode conversion performance of the converter is tested by far-field measurement method. And the experimental result confirms the validity of our design. Then, high power microwave experiment is carried out on a Marx-driven Blumlein water line pulsed power accelerator. Microwave frequency, radiated pattern and power are measured in the far-field region and the results agree well with simulation results. The experiment also reveals that no microwave breakdown or pulse shortening took place in the experimental setup.

  3. Predicting High-Power Performance in Professional Cyclists.

    Science.gov (United States)

    Sanders, Dajo; Heijboer, Mathieu; Akubat, Ibrahim; Meijer, Kenneth; Hesselink, Matthijs K

    2017-03-01

    To assess if short-duration (5 to ~300 s) high-power performance can accurately be predicted using the anaerobic power reserve (APR) model in professional cyclists. Data from 4 professional cyclists from a World Tour cycling team were used. Using the maximal aerobic power, sprint peak power output, and an exponential constant describing the decrement in power over time, a power-duration relationship was established for each participant. To test the predictive accuracy of the model, several all-out field trials of different durations were performed by each cyclist. The power output achieved during the all-out trials was compared with the predicted power output by the APR model. The power output predicted by the model showed very large to nearly perfect correlations to the actual power output obtained during the all-out trials for each cyclist (r = .88 ± .21, .92 ± .17, .95 ± .13, and .97 ± .09). Power output during the all-out trials remained within an average of 6.6% (53 W) of the predicted power output by the model. This preliminary pilot study presents 4 case studies on the applicability of the APR model in professional cyclists using a field-based approach. The decrement in all-out performance during high-intensity exercise seems to conform to a general relationship with a single exponential-decay model describing the decrement in power vs increasing duration. These results are in line with previous studies using the APR model to predict performance during brief all-out trials. Future research should evaluate the APR model with a larger sample size of elite cyclists.

  4. High-efficiency ultrashort pulse generation in a high-gain FEL oscillator near the perfect synchronism

    CERN Document Server

    Hajima, R; Nagai, R; Minehara, E J

    2002-01-01

    It has been verified experimentally in JAERI-FEL that a high-gain FEL oscillator has the maximum extraction efficiency at the perfect synchronism of optical-cavity length. The simultaneous measurement of FEL efficiency and absolute cavity length has clearly shown that a sharp peak of detuning curve at the perfect synchronism appears in high-gain and low-loss regime and the FEL extraction efficiency exceeds the scaling law of short-bunch FEL oscillators. A numerical analysis indicates that lasing at the perfect synchronism is quasi-stationary superradiance with random fluctuations, which is analogous to a SASE FEL. Second-order autocorrelation measurements show that FEL pulses shorter than four optical cycles are generated successively for a number of round trips at the perfect synchronism, which is consistent with numerical results.

  5. Magnetically coupled high-gain Y-source isolated DC/DC converter

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Loh, Poh Chiang; Blaabjerg, Frede

    2014-01-01

    A new form of magnetically coupled DC/DC converter is proposed for medium power applications (250 W to 2 kW), requiring a high-voltage gain, short inductive charging time and galvanic isolation. The proposed converter can be realised using a unique Y-source impedance network and a two-switch push......-pull circuit with voltage-doubling rectification. The converter's voltage gain is presently not matched by any other converter operating at the same switch duty ratio. The converter also has more degrees of freedom in design for setting the desired gain than other converters, and hence can better meet...... the demands of many applications. The operating principles of the converter have been analysed mathematically, and are verified by both simulation and experiment....

  6. Thrust stand for high-power electric propulsion devices

    Science.gov (United States)

    Haag, T. W.

    1991-01-01

    This paper describes a new high-power thrust stand developed for use with high-power (up to 250 kW) magnetoplasmadynamic (MPD) thrusters, which is installed in a high-vacuum MPD facility at Lewis Research Center. The design of the stand is based on inverted pendulum configuration, with the result of large displacements and high resolution. Calibration results showed that thrust measurements were linear and repeatable to within a fraction of 1 percent. The thrust stand was used for testing water-cooled MPD thrusters at power levels up to 125 kW. The thruster, however, is quite well suited for testing other types of electric propulsion devices.

  7. Hollow-core fibers for high power pulse delivery

    DEFF Research Database (Denmark)

    Michieletto, Mattia; Lyngsø, Jens K.; Jakobsen, Christian

    2016-01-01

    We investigate hollow-core fibers for fiber delivery of high power ultrashort laser pulses. We use numerical techniques to design an anti-resonant hollow-core fiber having one layer of non-touching tubes to determine which structures offer the best optical properties for the delivery of high power......-core fiber. The three fibers are characterized experimentally for the delivery of 22 picosecond pulses at 1032nm. We demonstrate flexible, diffraction limited beam delivery with output average powers in excess of 70W. (C) 2016 Optical Society of America...

  8. Flyer acceleration experiments using high-power laser

    Directory of Open Access Journals (Sweden)

    Kadono T.

    2013-11-01

    Full Text Available Flyer acceleration technique using high-power lasers has several advantages such as the achieved velocities higher than 10 km/s and non-contamination to the products generated by impacts. In this study, we show that a high-power laser can achieve flyer velocities higher than 10 km/s up to 60 km/s using spherical projectiles with a diameter of 0.1 − 0.3mm. We discuss the projectile condition during the flight based on the results of numerical simulations.

  9. High-power diode laser versus electrocautery surgery on human papillomavirus lesion treatment.

    Science.gov (United States)

    Baeder, Fernando Martins; Santos, Maria Teresa Botti R; Pelino, Jose Eduardo Pelizon; Duarte, Danilo Antonio; Genovese, Walter Joao

    2012-05-01

    The use of high-power lasers has facilitated and improved human papillomavirus (HPV) treatment protocols and has also become very popular in recent years. This application has been more frequently used in hospitals, especially in gynecology. The present study aimed to evaluate the effects of high-power diode laser to remove oral lesions caused by HPV and the consequent effects on virus load following the wound tissue healing process compared with one of the most conventional surgical techniques involving electrocautery. Surgeries were performed on 5 patients who had 2 distinct lesions caused by HPV. All patients were submitted to both electrocautery and high-power diode laser. Following a 20-day period, when the area was healed, sample material was collected through curettage for virus load quantitative analysis.Observation verified the presence of virus in all the samples; however, surgeries performed with the laser also revealed a significant reduction in virus load per cell compared with those performed with electrocautery. The ease when handling the diode laser, because of the flexibility of its fibers and precision of its energy delivery system, provides high-accuracy surgery, which facilitates the treatment of large and/or multifocal lesions. The use of high-power diode laser is more effective in treatment protocols of lesions caused by HPV.

  10. High-gain and fast-response metal-semiconductor-metal structured organolead halide perovskite photodetectors

    Science.gov (United States)

    Yang, Jie; Yu, Tao; Zhu, Kai; Xu, Qingyu

    2017-12-01

    Organolead halide perovskite photodetectors with a simple metal-semiconductor-metal (M-S-M) structure were fabricated. The photodetectors exhibit high optoelectronic performance with a high photoconductive gain in the order of 102 and high responsivity above 150 A W‑1. Meanwhile, the photodetectors show a large linear dynamic range of 120 dB, and a short response time of 0.67 µs. The organolead halide perovskite photodetectors with a simple M-S-M structure demonstrate great potential for low-cost and high-performance optoelectronic device applications.

  11. High-Gain Graphene Transistors with a Thin AlOx Top-Gate Oxide.

    Science.gov (United States)

    Guerriero, Erica; Pedrinazzi, Paolo; Mansouri, Aida; Habibpour, Omid; Winters, Michael; Rorsman, Niklas; Behnam, Ashkan; Carrion, Enrique A; Pesquera, Amaia; Centeno, Alba; Zurutuza, Amaia; Pop, Eric; Zirath, Herbert; Sordan, Roman

    2017-05-25

    The high-frequency performance of transistors is usually assessed by speed and gain figures of merit, such as the maximum oscillation frequency f max, cutoff frequency f T, ratio f max/f T, forward transmission coefficient S 21, and open-circuit voltage gain A v. All these figures of merit must be as large as possible for transistors to be useful in practical electronics applications. Here we demonstrate high-performance graphene field-effect transistors (GFETs) with a thin AlOx gate dielectric which outperform previous state-of-the-art GFETs: we obtained f max/f T > 3, A v > 30 dB, and S 21 = 12.5 dB (at 10 MHz and depending on the transistor geometry) from S-parameter measurements. A dc characterization of GFETs in ambient conditions reveals good current saturation and relatively large transconductance ~600 S/m. The realized GFETs offer the prospect of using graphene in a much wider range of electronic applications which require substantial gain.

  12. High-gain inverters based on WSe2 complementary field-effect transistors.

    Science.gov (United States)

    Tosun, Mahmut; Chuang, Steven; Fang, Hui; Sachid, Angada B; Hettick, Mark; Lin, Yongjing; Zeng, Yuping; Javey, Ali

    2014-05-27

    In this work, the operation of n- and p-type field-effect transistors (FETs) on the same WSe2 flake is realized,and a complementary logic inverter is demonstrated. The p-FET is fabricated by contacting WSe2 with a high work function metal, Pt, which facilities hole injection at the source contact. The n-FET is realized by utilizing selective surface charge transfer doping with potassium to form degenerately doped n+ contacts for electron injection. An ON/OFF current ratio of >10(4) is achieved for both n- and p-FETs with similar ON current densities. A dc voltage gain of >12 is measured for the complementary WSe2 inverter. This work presents an important advance toward realization of complementary logic devices based on layered chalcogenide semiconductors for electronic applications.

  13. Fiber-Shaped Perovskite Solar Cells with High Power Conversion Efficiency.

    Science.gov (United States)

    Qiu, Longbin; He, Sisi; Yang, Jiahua; Deng, Jue; Peng, Huisheng

    2016-05-01

    A perovskite solar cell fiber is created with a high power conversion efficiency of 7.1% through a controllable deposition method. A combination of aligned TiO2 nanotubes, a uniform perovskite layer, and transparent aligned carbon nanotube sheet contributes to the high photovoltaic performance. It is flexible and stable, and can be woven into smart clothes for wearable applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Feasibility Experiments on the Demilitarization of Chemical Munitions by High Power Lasers. Part I. Cutting Experiments

    Science.gov (United States)

    1977-06-01

    this report may be obtained from the National Technical Information Service, U.S. Department of Commerce, Springfield, Virginia 22151. 4 I The findings...Project Maneger for Chemical Demilitarization and Installation Restoration UNCLASSIFIED Aberdeen Proving Ground, Ma-yland 21010 15a. DECLASSIFICATION... information on the economics of high power lasers in industrial applications. As a result of these preliminary discussions, it was decided to perform

  15. Novel, High-power, Mid-infrared Optical Source for the 5-12 Micron Spectrum

    Science.gov (United States)

    2011-12-01

    for the visible and ultraviolet ”, Advanced Solid- State Photonics, Denver, Colorado, USA, February 2009 3. M. Ebrahim-Zadeh, “Tunable, high...power, solid-state sources for the blue and ultraviolet ”, Lasers and applications in science and engineering (LASE 2009), Photonics West, San Jose, USA...XXIVth International Conference on Photochemistry , ICP 2009, Toledo, Spain, July 2009 9. M. Ebrahim-Zadeh, “Advances in laser wavelength conversion

  16. High Power Silicon Carbide (SiC) Power Processing Unit Development

    Science.gov (United States)

    Scheidegger, Robert J.; Santiago, Walter; Bozak, Karin E.; Pinero, Luis R.; Birchenough, Arthur G.

    2015-01-01

    NASA GRC successfully designed, built and tested a technology-push power processing unit for electric propulsion applications that utilizes high voltage silicon carbide (SiC) technology. The development specifically addresses the need for high power electronics to enable electric propulsion systems in the 100s of kilowatts. This unit demonstrated how high voltage combined with superior semiconductor components resulted in exceptional converter performance.

  17. Design of a Novel High Power V-Band Helix-Folded Waveguide Cascaded Traveling Wave Tube Amplifier

    Directory of Open Access Journals (Sweden)

    Tianxiang Zhuge

    2015-01-01

    Full Text Available A design of a V-band Helix-Folded Waveguide (H-FWG cascaded traveling wave tube (TWT is presented. In this cascaded structure, a digitized nonlinear theory model is put forward first to simulate these two types of the tubes by common process. Then, an initial design principle is proposed, which can design these two different kinds of tubes universally. Using this principle, a high-gain helix TWT is carefully designed as a first stage amplifier followed by a FWG TWT to obtain high power. Simulations predict that a peak power of 800 W with saturated gain of 60 dB from 55 GHz to 60 GHz can be achieved.

  18. High Power laser power conditioning system new discharge circuit research

    CERN Document Server

    Li Yi; Peng Han Sheng; Zhou Pei Zhang; Zheng Wan Guo; Guo Lang Fu; Chen Li Hua; Chen De Hui; Lai Gui You; Luan Yong Ping

    2002-01-01

    The new discharge circuit of power conditioning system for high power laser is studied. The theoretical model of the main discharge circuit is established. The pre-ionization circuit is studied in experiment. In addition, the explosion energy of the new large xenon lamp is successfully measured. The conclusion has been applied to 4 x 2 amplifier system

  19. Measurement of high-power microwave pulse under intense ...

    Indian Academy of Sciences (India)

    KALI-1000 pulse power system has been used to generate single pulse nanosecond duration high-power microwaves (HPM) from a virtual cathode oscillator (VIRCATOR) device. HPM power measurements were carried out using a transmitting–receiving system in the presence of intense high frequency (a few MHz) ...

  20. High Powered Rocketry: Design, Construction, and Launching Experience and Analysis

    Science.gov (United States)

    Paulson, Pryce; Curtis, Jarret; Bartel, Evan; Cyr, Waycen Owens; Lamsal, Chiranjivi

    2018-01-01

    In this study, the nuts and bolts of designing and building a high powered rocket have been presented. A computer simulation program called RockSim was used to design the rocket. Simulation results are consistent with time variations of altitude, velocity, and acceleration obtained in the actual flight. The actual drag coefficient was determined…

  1. High Power Factor Hybrid Rectifier | Odeh | Nigerian Journal of ...

    African Journals Online (AJOL)

    This paper presents the analysis of a new single-phase hybrid rectifier with high power factor (PF) and low harmonic distortion current. The proposed rectifier structure is composed of an ordinary single-phase diode rectifier with parallel connection of a switched converter. It is outlined that the switched converter is capable of ...

  2. A high power, tunable free electron maser for fusion

    NARCIS (Netherlands)

    Urbanus, W. H.; Bratman, V. L.; Bongers, W. A.; Caplan, M.; Denisov, G. G.; van der Geer, C. A. J.; Manintveld, P.; Militsyn, B.; Oomens, A. A. M.; Poelman, A. J.; Plomp, J.; Pluygers, J.; Savilov, A. V.; Smeets, P. H. M.; Sterk, A. B.; Verhoeven, A. G. A.

    2001-01-01

    The Fusion-FEM experiment, a high-power, electrostatic free-electron maser being built at the FOM-Institute for Plasma Physics 'Rijnhuizen', is operated at various frequencies. So far, experiments were done without a depressed collector, and the pulse length was limited to 12 mus.

  3. Functionally graded materials produced with high power lasers

    NARCIS (Netherlands)

    De Hosson, JTM; Ocelík, Vašek; Chandra, T; Torralba, JM; Sakai, T

    2003-01-01

    In this keynote paper two examples will be present of functionally graded materials produced with high power Nd:YAG lasers. In particular the conditions for a successful Laser Melt Injection (LMI) of SiC and WC particles into the melt pool of A18Si and Ti6Al4V alloys are presented. The formation of

  4. Ignition studies in support of the European High Power Laser ...

    Indian Academy of Sciences (India)

    The European High Power Laser Energy Research Facility (HiPER) project is one of a number of large-scale scientific infrastructure projects supported by the European Commission's Seventh Framework Programme (FP7). Part of this project involves the development of a target area for the exploration of inertial fusion ...

  5. In-situ strain observation in high power laser cladding

    NARCIS (Netherlands)

    Ocelik, V.; Bosgra, J.; de Hosson, J. Th. M.

    2009-01-01

    The modern experimental technique - so called Digital Image Correlation - is applied during high power laser surface treatments for in-situ observation of displacements and strains near the processing area during and a short time after laser processing. An experimental setup has been designed and

  6. Device for wavefront correction in an ultra high power laser

    Science.gov (United States)

    Ault, Earl R.; Comaskey, Brian J.; Kuklo, Thomas C.

    2002-01-01

    A system for wavefront correction in an ultra high power laser. As the laser medium flows past the optical excitation source and the fluid warms its index of refraction changes creating an optical wedge. A system is provided for correcting the thermally induced optical phase errors.

  7. Possibilities of production of nanopowders with high power ELV ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 34; Issue 4. Possibilities of production of nanopowders with high power ELV electron accelerator. Vladimir Ivanovich Lysenko Sergey Bardakhanov Alexey Korchagin Nikolay Kuksanov Alexander Lavrukhin Rustam Salimov Sergey Fadeev Vladislav Cherepkov Mikhail ...

  8. High Power Wind Generator Designs with Less or No PMs

    DEFF Research Database (Denmark)

    Boldea, Ion; Tutelea, Lucian; Blaabjerg, Frede

    2014-01-01

    synchronous generators, by doubly-fed (wound rotor) induction and cage induction generators and by introducing new topologies with pertinent costs for high power (MW range) wind energy conversion units. The present overview attempts, based on recent grid specifications, an evaluation of commercial and novel...

  9. Rapid heating of matter using high power lasers

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Woosuk [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-04-08

    This slide presentation describes motivation (uniform and rapid heating of a target, opportunity to study warm dense matter, study of nuclear fusion reactions), rapid heating of matter with intense laser-driven ion beams, visualization of the expanding warm dense gold and diamond, and nuclear fusion experiments using high power lasers (direct heating of deuterium spheres (radius ~ 10nm) with an intense laser pulse.

  10. High-speed low-energy photoconductive receiver with high gain

    Science.gov (United States)

    Welker, Merlin; Zipperer, D.; Malzer, S.; Windisch, Reiner; Heremans, Paul L.; Doehler, Gottfried H.

    2001-06-01

    We report on an optoelectronic receiver consisting of a special photoconductive n-i-p detector and a n-i-p reference diode fabricated from the same structure. The receiver is illuminated by two surface-normal light beams using a dual rail code. All applied DC biases are compatible with normal silicon CMOS logic, no AC biasing is required. The photoconductive gain of the receiver allows for output currents of more than 10 mA without any further amplification. The active device area of the smallest detectors has been scaled down to 120 micrometers 2, resulting in a total optical switching energy for this receiver as low as 348 fJ. This optical switching energy is constant over a wide range of input power, resulting in fast switching times at sufficiently high input power while still retaining well-defined, but slower switching characteristics at lower input powers. Using input beams with 0.6 mW optical power at a wavelength of 787 nm, high speed measurements with a 3 dB frequency in excess of 400 MHz have been made. At these measurements a photoconductive gain of 6 times the p-i-n photocurrent was achieved, but using input powers of about 7 nW a gain in excess of 106 has been demonstrated. Due to their simple design and biasing demands these photoconductive receivers are well suited for smart pixel applications and optical interconnects. For demonstration we present results for new a monolithically integrated smart pixel with a high-efficiency non-resonant cavity LED as emitter.

  11. High-gain inertial confinement fusion by volume ignition, avoiding the complexities of fusion detonation fronts of spark ignition

    Energy Technology Data Exchange (ETDEWEB)

    Hora, H. [Univ. of New South Wales, Sydney, New South Wales (Australia). Dept. of Theoretical Physics; Eliezer, S. [Soreq Nuclear Research Center, Yavne (Israel); Honrubia, J.J.; Martinez-Val, J.M.; Valarde, G. [Univ. Politecnica de Madrid (Spain). Inst. de Fusion Nuclear; Miley, G.H. [Univ. of Illinois, Urbana, IL (United States). Fusion Studies Lab.; Hoepfl, R.

    1995-12-31

    The main approach to Inertial Confinement Fusion (ICF) uses a high-temperature, low-density core and a high-density, low-temperature outer region of the laser- (or ion beam-)compressed deuterium-tritium (D-T) fuel, in order to ignite a fusion detonation wave at the interface. This is an extremely delicate, unstable configuration which is very difficult to achieve, even with a carefully programmed time dependence of the deposition of the driver energy. This approach was devised in order to reach the high gains needed for low-efficiency lasers. Since 1978, several teams have developed an alternative scheme using volume ignition, where a natural and simple adiabatic compression, starting from a low initial temperature of 3 keV or less, is used. The high gains are obtained by self-heating due to the fusion reaction products plus self-absorption of Bremsstrahlung. Fortunately, a strong deviation from LTE occurs at ion temperatures above 100 keV, with much lower electron and even lower radiation temperatures. The authors report here how the gains calculated by different groups are relatively large, and despite detailed differences in the stopping power models, do not differ greatly. The high gain can be explained by introducing an effective value for the density-radius ({rho}R) product, where the volume ignition process increases the usual value of about 3 g-cm{sup {minus}2} to an effective value of 12 g-cm{sup {minus}2} or more, due to the self-generated additional heating that occurs for beam input energies > MJ and compression over 1,000 times solid state. This result is valid for direct drive as well as for indirect drive.

  12. Free-electron masers vs. gyrotrons prospects for high-power sources at millimeter and submillimeter wavelengths

    CERN Document Server

    Thumm, M K

    2002-01-01

    The possible applications of high-power millimeter (mm) and sub-mm waves from free-electron masers (FEMs) and gyro-devices span a wide range of technologies. The plasma physics community has already taken advantage of recent advances in applying high-power mm waves generated by long pulse or continuous wave (CW) gyrotron oscillators and short pulse very high-power FEMs in the areas of RF-plasma production, heating, non-inductive current drive, plasma stabilization and active plasma diagnostics for magnetic confinement thermonuclear fusion research, such as electron cyclotron resonance heating (28-170 GHz), electron cyclotron current drive , collective Thomson scattering , microwave transmission and heat-wave propagation experiments. Continuously frequency tunable FEMs could widen these fields of applications. Another important application of CW gyrotrons is industrial materials processing, e.g. sintering of high-performance functional and structural nanostructured ceramics. Sub-mm wave sources are employed in...

  13. Transverse and temporal characteristics of a high-gain free-electron laser in the saturation regime

    CERN Document Server

    Huang Zhi Rong

    2002-01-01

    The transverse and the temporal characteristics of a high-gain free-electron laser are governed by refractive guiding and sideband instability, respectively. Using the self-consistent Vlasov-Maxwell equations, we explicitly determine the effective index of refraction and the guided radiation mode for an electron beam with arbitrary transverse size. Electrons trapped by the guided radiation execute synchrotron oscillation and hence are susceptible to the sideband instability. We explain the spectral evolution and determine the sideband growth rate. These theoretical predictions agree well with GINGER simulation results.

  14. Design and dSpace interfacing of current fed high gain dc to dc boost converter for low voltage applications

    Science.gov (United States)

    Mukhopadhyay, Debraj; Das, Subhrajit; Arunkumar, G.; Elangovan, D.; Ragunath, G.

    2017-11-01

    In this paper a current fed interleaved DC - DC boost converter which has an isolated topology and used for high voltage step up is proposed. A basic DC to DC boost converter converts uncontrolled DC voltage into controlled DC voltage of higher magnitude. Whereas this topology has the advantages of lower input current ripple, lesser output voltage, lesser stress on switches, faster transient response, improved reliability and much lesser electromagnetic emission over the conventional DC to DC boost converter. Most important benefit of this interleaved DC to DC boost converter is much higher efficiency. The input current is divided into two paths, substantially ohmic loss (I2R) and inductor ac loss gets reduced and finally the system achieves much higher efficiency. With recent mandates on energy saving interleaved DC to DC boost converter may be used as a very powerful tool to maintain good power density keeping the input current manageable. Higher efficiency also allows higher switching frequency and as a result the topology becomes more compact and cost friendly. The proposed topology boosts 48v DC to 200 V DC. Switching frequency is 100 kHz and PSIM 9.1 Platform has been used for the simulation.

  15. A new design methodology of obtaining wide band high gain broadband parametric source for infrared wavelength applications

    Energy Technology Data Exchange (ETDEWEB)

    Maji, Partha Sona; Roy Chaudhuri, Partha [Department of Physics, Indian Institute of Technology, Kharagpur 721302 (India)

    2016-03-21

    In this article, we have presented a new design methodology of obtaining wide band parametric sources based on highly nonlinear chalcogenide material of As{sub 2}S{sub 3}. The dispersion profile of the photonic crystal fiber (PCF) has been engineered wisely by reducing the diameter of the second air-hole ring to have a favorable higher order dispersion parameter. The parametric gain dependence upon fiber length, pump power, and different pumping wavelengths has been investigated in detail. Based upon the nonlinear four wave mixing phenomenon, we are able to achieve a wideband parametric amplifier with peak gain of 29 dB with FWHM of ≈2000 nm around the IR wavelength by proper tailoring of the dispersion profile of the PCF with a continuous wave Erbium (Er{sup 3+})-doped ZBLAN fiber laser emitting at 2.8 μm as the pump source with an average power of 5 W. The new design methodology will unleash a new dimension to the chalcogenide material based investigation for wavelength translation around IR wavelength band.

  16. Reliability of high power/brightness diode lasers emitting from 790 to 980 nm

    Science.gov (United States)

    Bao, L.; Bai, J.; Price, K.; Devito, M.; Grimshaw, M.; Dong, W.; Guan, X.; Zhang, S.; Zhou, H.; Bruce, K.; Dawson, D.; Kanskar, M.; Martinsen, R.; Haden, J.

    2013-02-01

    This paper presents recent progress in the development of high power single emitter laser diodes from 790 nm to 980 nm for reliable use in industrial and pumping applications. High performance has been demonstrated on diode lasers from 790 nm to 980 nm, with corresponding peak efficiency ~65%. Reliability has been fully demonstrated on high power diode lasers of 3.8 mm laser cavity at 3 major wavelengths. We report on the correlation between photon-energy (wavelength) and device failure modes (reliability). A newly released laser design demonstrates diode lasers with 5.0 mm laser cavity at 915-980 nm and 790 nm, with efficiency that matches the values achieved with 3.8 mm cavity length. 915-980 nm single emitters with 5.0 mm laser cavity were especially designed for high power and high brightness applications and can be reliably operated at 12 W to 18 W. These pumps have been incorporated into nLIGHT's newly developed fiber coupled pump module, elementTM. Ongoing highly accelerated diode life-tests have accumulated over 200,000 raw device hours, with extremely low failure rate observed to date. High reliability has also been demonstrated from multiple accelerated module-level lifetests.

  17. State of art survey for design of medium frequency high power transformer

    DEFF Research Database (Denmark)

    Vaisambhayana, Sriram; Dincan, Catalin; Shuyu, Cao

    2016-01-01

    Medium and high frequency, high power transformers play an important role in footprint reduction along with their functions of galvanic isolation, and voltage transformation in all high power converters typically used in traction power systems, offshore wind plant power converters, and solid state...... transformer based distribution system grids. This state of art report analysis the various materials and design tradeoffs that govern the electromagnetic behavior and loss mechanisms of the medium frequency transformer applications. Typical winding and core geometries that have been reported extensively...... in the literature are described, and some design procedures and flow charts are analyzed including specific optimization routines. Estimation of core loss at high frequency using Steinmetz method and other modified methods are shown in detail. Thermal modelling including static and dynamic methods available...

  18. High-power light-emitting diode based facility for plant cultivation

    Energy Technology Data Exchange (ETDEWEB)

    Tamulaitis, G [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania); Duchovskis, P [Lithuanian Institute of Horticulture, Babtai, LT-54333 Kaunas District (Lithuania); Bliznikas, Z [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania); Breive, K [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania); Ulinskaite, R [Lithuanian Institute of Horticulture, Babtai, LT-54333 Kaunas District (Lithuania); Brazaityte, A [Lithuanian Institute of Horticulture, Babtai, LT-54333 Kaunas District (Lithuania); Novickovas, A [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania); Zukauskas, A [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania)

    2005-09-07

    Based on perspectives of the development of semiconductor materials systems for high-power light-emitting diodes (LEDs), an illumination facility for greenhouse plant cultivation was designed with the dominating 640 nm photosynthetically active component delivered by AlGaInP LEDs and supplementary components from AlGaN (photothropic action, 455 nm) and AlGaAs (photosynthetic 660 nm and photomorphogenetic 735 nm) LEDs. Photosynthesis intensity, photosynthetic productivity and growth morphology as well as chlorophyll and phytohormone concentrations were investigated in radish and lettuce grown in phytotron chambers under the LED-based illuminators and under high-pressure sodium (HPS) lamps with an equivalent photon flux density. Advantages of the high-power LED-based illuminators over conventional HPS lamps, applicability of AlGaInP LEDs for photosynthesis and control of plant growth by circadian manipulation of a relatively weak far-red component were demonstrated.

  19. FEM Thermal Modeling and Improvement for High Power IGBT Modules Used in Wind Turbine Systems

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede

    2014-01-01

    Thermal management of high power IGBT (Insulated Gate Bipolar Transistor) modules is crucial to ensure the reliable operation of power electronic systems especially in wind power applications. The important stage in thermal management of power modules is temperature estimation inside the IGBT...... modules. Generally, thermal information on datasheet is used to estimate transistor and diode chip temperatures, but this information is based on average and rough temperature measurements. In addition this information does not consider thermal coupling impact between the chips and the impact of different...... cooling conditions on thermal behavior of power module. In this paper, a detailed 3D thermal network of high power module is presented based on FEM (Finite Element Method) simulation. The thermal coupling impact between chips will be studied and the transient thermal impedances will be examined under...

  20. A robust pulsating heat pipe cooler for integrated high power LED chips

    Science.gov (United States)

    Lv, Lucang; Li, Ji; Zhou, Guohui

    2017-11-01

    This paper presents a closed loop pulsating heat pipe (CLPHP) with specific pipe arrangement for high power LED cooling. Two CLPHPs were fabricated and charged with DI water and methanol, respectively. The effects of gravity force and working fluid on the heat transfer performance were investigated carefully. Results show that the water-CLPHP performed better than the methanol-CLPHP, with a minimum thermal resistance of 0.06 °C/W at a 220 W heat load under air natural convection situation. In addition, the gravity force can help the CLPHP starting up and enhance the robustness of the thermal transportation at steady state. Finally, the real application to cooling a 100 W LED chip indicates that the proposed CLPHP can meet the thermal control requirement for integrated high power LEDs. Nevertheless, the low cost and light weight of the proposed CLPHP heat sink are very suitable for the LED lighting devices.

  1. A rationale for the use of high-powered magnification or microscopes in general dentistry.

    Science.gov (United States)

    Mamoun, John S

    2009-01-01

    This article argues that high-powered magnification (4x-6x or more) provides substantially more visual information for diagnosing and treating dental pathology compared to the use of unaided vision or entry-level 2.5x magnification. In all phases of general dentistry, the increased visual detail provided by high magnification reduces ambiguity in diagnosis and treatment decision-making, increases control in treatment implementation, allows a dentist to produce more ergonomic restorations that are less prone to recurrent decay, and arguably improves clinical outcomes compared to work performed with unaided vision. High magnification enhances a dentist's ability to diagnose caries and cracks in teeth, distinguish between different colors intraorally, detect the interfaces between different surfaces and materials, detect microscopic interferences in fixed and removable metal frameworks, adjust occlusal prematurities, and polish restorations. This article explains specific general dental applications for high-powered magnification in restorative dentistry, fixed and removable prosthodontics, endodontics, pediatric dentistry, periodontics, and oral surgery.

  2. Thermal tuning of volume Bragg gratings for spectral beam combining of high-power fiber lasers.

    Science.gov (United States)

    Drachenberg, Derrek R; Andrusyak, Oleksiy; Venus, George; Smirnov, Vadim; Glebov, Leonid B

    2014-02-20

    High-radiance lasers are desired for many applications in defense and manufacturing. Spectral beam combining (SBC) by volume Bragg gratings (VBGs) is a very promising method for high-radiance lasers that need to achieve 100 kW level power. Laser-induced heating of VBGs under high-power radiation presents a challenge for maintaining Bragg resonance at various power levels without mechanical realignment. A novel thermal tuning technique and apparatus is presented that enables maintaining peak efficiency operation of the SBC system at various power levels without any mechanical adjustment. The method is demonstrated by combining two high-power ytterbium fiber lasers with high efficiency from low power to full combined power of 300 W (1.5 kW effective power), while maintaining peak combining efficiency within 0.5%.

  3. Switching speed limitations of high power IGBT modules

    DEFF Research Database (Denmark)

    Incau, Bogdan Ioan; Trintis, Ionut; Munk-Nielsen, Stig

    2015-01-01

    In this paper the switching speed limits of high power IGBT modules are investigated. The limitation of turn-on and turn-off switching speeds of the IGBTs are experimentally detected in a pulse tester. Different dc-bus stray inductances are considered, as well as the worst case scenario for the b......In this paper the switching speed limits of high power IGBT modules are investigated. The limitation of turn-on and turn-off switching speeds of the IGBTs are experimentally detected in a pulse tester. Different dc-bus stray inductances are considered, as well as the worst case scenario...... for the blocking dc-link voltage. Switching losses are analyzed upon a considerable variation of resistor value from turn-on gate driver side. Short circuit operations are investigated along with safe operating area for entire module to validate electrical capabilities under extreme conditions....

  4. High-Power ZBLAN Glass Fiber Lasers: Review and Prospect

    Directory of Open Access Journals (Sweden)

    Xiushan Zhu

    2010-01-01

    Full Text Available ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF, considered as the most stable heavy metal fluoride glass and the excellent host for rare-earth ions, has been extensively used for efficient and compact ultraviolet, visible, and infrared fiber lasers due to its low intrinsic loss, wide transparency window, and small phonon energy. In this paper, the historical progress and the properties of fluoride glasses and the fabrication of ZBLAN fibers are briefly described. Advances of infrared, upconversion, and supercontinuum ZBLAN fiber lasers are addressed in detail. Finally, constraints on the power scaling of ZBLAN fiber lasers are analyzed and discussed. ZBLAN fiber lasers are showing promise of generating high-power emissions covering from ultraviolet to mid-infrared considering the recent advances in newly designed optical fibers, beam-shaped high-power pump diodes, beam combining techniques, and heat-dissipating technology.

  5. Designing high power targets with computational fluid dynamics (CFD)

    Energy Technology Data Exchange (ETDEWEB)

    Covrig, Silviu D. [JLAB

    2013-11-01

    High power liquid hydrogen (LH2) targets, up to 850 W, have been widely used at Jefferson Lab for the 6 GeV physics program. The typical luminosity loss of a 20 cm long LH2 target was 20% for a beam current of 100 {micro}A rastered on a square of side 2 mm on the target. The 35 cm long, 2500 W LH2 target for the Qweak experiment had a luminosity loss of 0.8% at 180 {micro}A beam rastered on a square of side 4 mm at the target. The Qweak target was the highest power liquid hydrogen target in the world and with the lowest noise figure. The Qweak target was the first one designed with CFD at Jefferson Lab. A CFD facility is being established at Jefferson Lab to design, build and test a new generation of low noise high power targets.

  6. Designing high power targets with computational fluid dynamics (CFD)

    Energy Technology Data Exchange (ETDEWEB)

    Covrig, S. D. [Thomas Jefferson National Laboratory, Newport News, VA 23606 (United States)

    2013-11-07

    High power liquid hydrogen (LH2) targets, up to 850 W, have been widely used at Jefferson Lab for the 6 GeV physics program. The typical luminosity loss of a 20 cm long LH2 target was 20% for a beam current of 100 μA rastered on a square of side 2 mm on the target. The 35 cm long, 2500 W LH2 target for the Qweak experiment had a luminosity loss of 0.8% at 180 μA beam rastered on a square of side 4 mm at the target. The Qweak target was the highest power liquid hydrogen target in the world and with the lowest noise figure. The Qweak target was the first one designed with CFD at Jefferson Lab. A CFD facility is being established at Jefferson Lab to design, build and test a new generation of low noise high power targets.

  7. Website Design Guidelines: High Power Distance and High Context Culture

    Directory of Open Access Journals (Sweden)

    Tanveer Ahmed

    2009-06-01

    Full Text Available This paper aims to address the question of offering a culturally adapted website for a local audience. So far, in the website design arena the vast majority of studies examined mainly Western and the American (low power distance and low context culture disregarding possible cultural discrepancies. This study fills this gap and explores the key cultural parameters that are likely to have an impact on local website design for Asian-Eastern culture high power distance and high context correlating with both Hofstede’s and Hall’s cultural dimensions. It also reviews how website localisation may be accomplished more effectively by extracting the guidelines from two different yet compatible cultural dimensions: high power distance and high context.

  8. Iron loss in high-power arc steelmaking furnaces

    Directory of Open Access Journals (Sweden)

    V. P. Karasyov

    2016-07-01

    Full Text Available There is considered the power operating mode of a high-power arc steelmaking furnaces (ASMF in the period of the flat bath. It is revealed that electric energy is mainly spent for heating and overheating the foamed slag. Heat transferring from slag to metal is carried out by the convective agitation of the bath. For agitation there is used intensive purging of the bath with oxygen that causes increased iron losses with the running foamed slag. There are noted the negative points of working with the foamed slag. It is recommended to expand R&D in the field of optimizing the power operating mode of high-power ASMF.

  9. Transient Plasma Photonic Crystals for High-Power Lasers.

    Science.gov (United States)

    Lehmann, G; Spatschek, K H

    2016-06-03

    A new type of transient photonic crystals for high-power lasers is presented. The crystal is produced by counterpropagating laser beams in plasma. Trapped electrons and electrically forced ions generate a strong density grating. The lifetime of the transient photonic crystal is determined by the ballistic motion of ions. The robustness of the photonic crystal allows one to manipulate high-intensity laser pulses. The scheme of the crystal is analyzed here by 1D Vlasov simulations. Reflection or transmission of high-power laser pulses are predicted by particle-in-cell simulations. It is shown that a transient plasma photonic crystal may act as a tunable mirror for intense laser pulses. Generalizations to 2D and 3D configurations are possible.

  10. Modeling, fabrication and high power optical characterization of plasmonic waveguides

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Lysenko, Oleg

    2015-01-01

    , 30 and 45 nm. The fabrication process of such plasmonic waveguides with width in the range of 1-100 μm and their quality inspection are described. The results of optical characterization of plasmonic waveguides using a high power laser with the peak power wavelength 1064 nm show significant deviation......This paper describes modeling, fabrication and high power optical characterization of thin gold films embedded in silicon dioxide. The propagation vector of surface plasmon polaritons has been calculated by the effective index method for the wavelength range of 750-1700 nm and film thickness of 15...... from the linear propagation regime of surface plasmon polaritons at the average input power of 100 mW and above. Possible reasons for this deviation are heating of the waveguides and subsequent changes in the coupling and propagation losses....

  11. CAS Accelerator Physics (High-Power Hadron Machines) in Spain

    CERN Multimedia

    CAS

    2011-01-01

    The CERN Accelerator School (CAS) and ESS-Bilbao jointly organised a specialised course on High-Power Hadron Machines, held at the Hotel Barceló Nervión in Bilbao, Spain, from 24 May to 2 June, 2011.   CERN Accelerator School students. After recapitulation lectures on the essentials of accelerator physics and review lectures on the different types of accelerators, the programme focussed on the challenges of designing and operating high-power facilities. The particular problems for RF systems, beam instrumentation, vacuum, cryogenics, collimators and beam dumps were examined. Activation of equipment, radioprotection and remote handling issues were also addressed. The school was very successful, with 69 participants of 22 nationalities. Feedback from the participants was extremely positive, praising the expertise and enthusiasm of the lecturers, as well as the high standard and excellent quality of their lectures. In addition to the academic programme, the participants w...

  12. High-Power Microwave Transmission and Mode Conversion Program

    Energy Technology Data Exchange (ETDEWEB)

    Vernon, Ronald J. [Univ. of Wisconsin, Madison, WI (United States)

    2015-08-14

    This is a final technical report for a long term project to develop improved designs and design tools for the microwave hardware and components associated with the DOE Plasma Fusion Program. We have developed basic theory, software, fabrication techniques, and low-power measurement techniques for the design of microwave hardware associated gyrotrons, microwave mode converters and high-power microwave transmission lines. Specifically, in this report we discuss our work on designing quasi-optical mode converters for single and multiple frequencies, a new method for the analysis of perturbed-wall waveguide mode converters, perturbed-wall launcher design for TE0n mode gyrotrons, quasi-optical traveling-wave resonator design for high-power testing of microwave components, and possible improvements to the HSX microwave transmission line.

  13. High power operational experience with the LANSCE Linac

    Energy Technology Data Exchange (ETDEWEB)

    Rybarcyk, Lawrence J [Los Alamos National Laboratory

    2008-01-01

    The heart of the Los Alamos Neutron Science Center (LANSCE) is a pulsed linear accelerator that is used to simultaneously provide H+ and H- beams to several user facilities. This accelerator contains two Cockcroft-Walton style injectors, a 100-MeV drift tube linac and an 800-MeV coupled cavity linac. This presentation will touch on various aspects of the high power operation including performance, tune-up strategy, beam losses and machine protection.

  14. Development of adaptive resonator techniques for high-power lasers

    Energy Technology Data Exchange (ETDEWEB)

    An, J; Brase, J; Carrano, C; Dane, C B; Flath, L; Fochs, S; Hurd, R; Kartz, M; Sawvel, R

    1999-07-12

    The design of an adaptive wavefront control system for a high-power Nd:Glass laser will be presented. Features of this system include: an unstable resonator in confocal configuration, a multi-module slab amplifier, and real-time intracavity adaptive phase control using deformable mirrors and high-speed wavefront sensors. Experimental results demonstrate the adaptive correction of an aberrated passive resonator (no gain).

  15. Transmission grating stretcher for contrast enhancement of high power lasers.

    Science.gov (United States)

    Tang, Yunxin; Hooker, Chris; Chekhlov, Oleg; Hawkes, Steve; Collier, John; Rajeev, P P

    2014-12-01

    We propose, for the first time, a transmission grating stretcher for high power lasers and demonstrate its superiority over conventional, reflective gold grating stretchers in terms of pulse temporal quality. We show that, compared to a conventional stretcher with the same stretching factor, the transmission-grating based stretcher yields more than an order of magnitude improvement in the contrast pedestal. We have also quantitatively characterized the roughness of the grating surfaces and estimated its impact on the contrast pedestal.

  16. Recent results in mirror based high power laser cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Nielsen, Jakob Skov; Elvang, Mads

    2004-01-01

    In this paper, recent results in high power laser cutting, obtained in reseach and development projects are presented. Two types of mirror based focussing systems for laser cutting have been developed and applied in laser cutting studies on CO2-lasers up to 12 kW. In shipyard environment cutting...... speed increase relative to state-of-the-art cutting of over 100 % has been achieved....

  17. On the Fielding of a High Gain, Shock-Ignited Target on the National Ignitiion Facility in the Near Term

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, L J; Betti, R; Schurtz, G P; Craxton, R S; Dunne, A M; LaFortune, K N; Schmitt, A J; McKenty, P W; Bailey, D S; Lambert, M A; Ribeyre, X; Theobald, W R; Strozzi, D J; Harding, D R; Casner, A; Atzemi, S; Erbert, G V; Andersen, K S; Murakami, M; Comley, A J; Cook, R C; Stephens, R B

    2010-04-12

    Shock ignition, a new concept for igniting thermonuclear fuel, offers the possibility for a near-term ({approx}3-4 years) test of high gain inertial confinement fusion on the National Ignition Facility at less than 1MJ drive energy and without the need for new laser hardware. In shock ignition, compressed fusion fuel is separately ignited by a strong spherically converging shock and, because capsule implosion velocities are significantly lower than those required for conventional hotpot ignition, fusion energy gains of {approx}60 may be achievable on NIF at laser drive energies around {approx}0.5MJ. Because of the simple all-DT target design, its in-flight robustness, the potential need for only 1D SSD beam smoothing, minimal early time LPI preheat, and use of present (indirect drive) laser hardware, this target may be easier to field on NIF than a conventional (polar) direct drive hotspot ignition target. Like fast ignition, shock ignition has the potential for high fusion yields at low drive energy, but requires only a single laser with less demanding timing and spatial focusing requirements. Of course, conventional symmetry and stability constraints still apply. In this paper we present initial target performance simulations, delineate the critical issues and describe the immediate-term R&D program that must be performed in order to test the potential of a high gain shock ignition target on NIF in the near term.

  18. Performance of a Combined System Using an X-Ray FEL Oscillator and a High-Gain FEL Amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, L.; Lindberg, R.; Kim, K. -J.

    2017-06-01

    The LCLS-II at SLAC will feature a 4 GeV CW superconducting (SC) RF linac [1] that can potentially drive a 5th harmonic X-Ray FEL Oscillator (XFELO) to produce fully coherent, 1 MW photon pulses with a 5 meV bandwidth at 14.4 keV [2]. The XFELO output can serve as the input seed signal for a high-gain FEL amplifier employing fs electron beams from the normal conducting SLAC linac, thereby generating coherent, fs x-ray pulses with TW peak powers using a tapered undulator after saturation [3]. Coherent, intense output at several tens of keV will also be feasible if one considers a harmonic generation scheme. Thus, one can potentially reach the 42 keV photon energy required for the MaRIE project [4] by beginning with an XFELO operating at the 3rd harmonic to produce 14.0 keV photons using a 12 GeV SCRF linac, and then subsequently using the high-gain harmonic generation scheme to generate and amplify the 3th harmonic at 42 keV [5]. We report extensive GINGER simulations that determine an optimized parameter set for the combined system.

  19. High-power CSI-fed induction motor drive with optimal power distribution based control

    Science.gov (United States)

    Kwak, S.-S.

    2011-11-01

    In this article, a current source inverter (CSI) fed induction motor drive with an optimal power distribution control is proposed for high-power applications. The CSI-fed drive is configured with a six-step CSI along with a pulsewidth modulated voltage source inverter (PWM-VSI) and capacitors. Due to the PWM-VSI and the capacitor, sinusoidal motor currents and voltages with high quality as well as natural commutation of the six-step CSI can be obtained. Since this CSI-fed drive can deliver required output power through both the six-step CSI and PWM-VSI, this article shows that the kVA ratings of both the inverters can be reduced by proper real power distribution. The optimal power distribution under load requirements, based on power flow modelling of the CSI-fed drive, is proposed to not only minimise the PWM-VSI rating but also reduce the six-step CSI rating. The dc-link current control of the six-step CSI is developed to realise the optimal power distribution. Furthermore, a vector controlled drive for high-power induction motors is proposed based on the optimal power distribution. Experimental results verify the high-power CSI-fed drive with the optimal power distribution control.

  20. Long distance high power optical laser fiber break detection and continuity monitoring systems and methods

    Science.gov (United States)

    Rinzler, Charles C.; Gray, William C.; Faircloth, Brian O.; Zediker, Mark S.

    2016-02-23

    A monitoring and detection system for use on high power laser systems, long distance high power laser systems and tools for performing high power laser operations. In particular, the monitoring and detection systems provide break detection and continuity protection for performing high power laser operations on, and in, remote and difficult to access locations.

  1. AN ASSESSMENT OF FLYWHEEL HIGH POWER ENERGY STORAGE TECHNOLOGY FOR HYBRID VEHICLES

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, James Gerald [ORNL

    2012-02-01

    An assessment has been conducted for the DOE Vehicle Technologies Program to determine the state of the art of advanced flywheel high power energy storage systems to meet hybrid vehicle needs for high power energy storage and energy/power management. Flywheel systems can be implemented with either an electrical or a mechanical powertrain. The assessment elaborates upon flywheel rotor design issues of stress, materials and aspect ratio. Twelve organizations that produce flywheel systems submitted specifications for flywheel energy storage systems to meet minimum energy and power requirements for both light-duty and heavy-duty hybrid applications of interest to DOE. The most extensive experience operating flywheel high power energy storage systems in heavy-duty and light-duty hybrid vehicles is in Europe. Recent advances in Europe in a number of vehicle racing venues and also in road car advanced evaluations are discussed. As a frame of reference, nominal weight and specific power for non-energy storage components of Toyota hybrid electric vehicles are summarized. The most effective utilization of flywheels is in providing high power while providing just enough energy storage to accomplish the power assist mission effectively. Flywheels are shown to meet or exceed the USABC power related goals (discharge power, regenerative power, specific power, power density, weight and volume) for HEV and EV batteries and ultracapacitors. The greatest technical challenge facing the developer of vehicular flywheel systems remains the issue of safety and containment. Flywheel safety issues must be addressed during the design and testing phases to ensure that production flywheel systems can be operated with adequately low risk.

  2. Investigation of the delay time distribution of high power microwave surface flashover

    Science.gov (United States)

    Foster, J.; Krompholz, H.; Neuber, A.

    2011-01-01

    Characterizing and modeling the statistics associated with the initiation of gas breakdown has proven to be difficult due to a variety of rather unexplored phenomena involved. Experimental conditions for high power microwave window breakdown for pressures on the order of 100 to several 100 torr are complex: there are little to no naturally occurring free electrons in the breakdown region. The initial electron generation rate, from an external source, for example, is time dependent and so is the charge carrier amplification in the increasing radio frequency (RF) field amplitude with a rise time of 50 ns, which can be on the same order as the breakdown delay time. The probability of reaching a critical electron density within a given time period is composed of the statistical waiting time for the appearance of initiating electrons in the high-field region and the build-up of an avalanche with an inherent statistical distribution of the electron number. High power microwave breakdown and its delay time is of critical importance, since it limits the transmission through necessary windows, especially for high power, high altitude, low pressure applications. The delay time distribution of pulsed high power microwave surface flashover has been examined for nitrogen and argon as test gases for pressures ranging from 60 to 400 torr, with and without external UV illumination. A model has been developed for predicting the discharge delay time for these conditions. The results provide indications that field induced electron generation, other than standard field emission, plays a dominant role, which might be valid for other gas discharge types as well.

  3. A High-gain and Low-scattering Waveguide Slot Antenna of Artificial Magnetic Conductor Octagonal Ring Arrangement

    Directory of Open Access Journals (Sweden)

    X. Liu

    2016-04-01

    Full Text Available A novel design of high-gain and low-scattering waveguide slot antenna is proposed in this paper. Firstly the scattering pattern of artificial magnetic conductor (AMC composite surface is estimated by array factor analysis method. The comparison between octagonal ring arrangement and chessboard arrangement proves that the former arrangement has the characteristic of diffuseness-like and expands the bandwidth of radar cross section (RCS reduction. Secondly, the metal surface of waveguide slot antenna (WSA is replaced by the octagonal ring arrangement composite surface (ORACS. The gain is improved because of spurious radiation units which are around the slot. At the same time using the phase cancellation principle, a backscatter null achieves RCS reduction in the vertical direction. Experimental results show that the novel antenna after loading with the ORACS, the gain is improved by 5dB; the bandwidth of RCS reduction (reduction greater than 10dB is 5.24-5.92 GHz.

  4. Quantum spatial correlations in high-gain parametric down-conversion measured by means of a CCD camera

    DEFF Research Database (Denmark)

    Jedrkiewicz, O.; Brambilla, E.; Bache, Morten

    2006-01-01

    We consider travelling-wave parametric down-conversion in the high-gain regime and present the experimental demonstration of the quantum character of the spatial fluctuations in the system. In addition to showing the presence of sub-shot noise fluctuations in the intensity difference, we...... demonstrate that the peak value of the normalized spatial correlations between signal and idler lies well above the line marking the boundary between the classical and the quantum domain. This effect is equivalent to the apparent violation of the Cauchy-Schwartz inequality, predicted by some of us years ago......, which represents a spatial analogue of photon antibunching in time. Finally, we analyse numerically the transition from the quantum to the classical regime when the gain is increased and we emphasize the role of the inaccuracy in the determination of the symmetry center of the signal/idler pattern...

  5. Optimum working interest in hydrocarbon exploration projects: the high gain situation revisited for cost, wealth and fear factors

    Energy Technology Data Exchange (ETDEWEB)

    Lerche, I.; MacKay, J.A.

    2003-10-01

    In exploration ventures where a high gain can be anticipated if the venture is successful, the risk adjusted value shows an anomalous behaviour with increasing value of the venture such that the optimum working interest first increases and then decreases as the value increases. This paradoxical behaviour was ''resolved'' previously by going outside the framework of the corresponding risk adjusted value formula and adding extraneous constraints. The present paper shows that a complete resolution to the paradox is available while staying precisely within the bounds of the corresponding risk adjusted value formula and without any extraneous constraints. This novel resolution allows one to use many of the risk adjusted formulae available under more general conditions than were thought to be relevant because of the appearance of what seemed to be an insurmountable paradox. A few simple numerical examples are provided to show how one handles this new resolution in pragmatic situations. (author)

  6. Emission characteristics of high-gain GaN-based Vertical-Cavity Surface-Emitting Lasers

    Science.gov (United States)

    Weng, Guoen; Chen, Shaoqiang; Ito, Takashi; Akiyama, Hidefumi; Hu, Xiaobo; Zhang, Baoping

    2017-06-01

    GaN-based vertical-cavity surface-emitting lasers (VCSELs) with high optical gain and short cavity lifetime are favorable for the generation of ultra-short pulses in the blue and green regions. In our previous works, 6 and 2 picosecond short-pulses have been generated from gain-switched InGaN VCSELs with 3- and 10-period InGaN/GaN quantum wells (QWs) in the active layers by using an up-conversion measurement system. To further increase the gain of the VCSEL for the generation of even shorter pulses, 20-period InGaN/GaN QWs samples were fabricated. The emission characteristics of these high-gain VCSELs were investigated and analyzed under the optical pumping at room temperature.

  7. Lithium niobate Q-switch to prevent pre-lasing of high gain lasers operating over a wide temperature range

    Science.gov (United States)

    Jundt, Dieter H.; MacKay, Peter E.

    2015-02-01

    Because of its ease of growth and large electro-optic effect, lithium niobate is the preferred choice for Q-switching mobile lasers. Temperature-induced pyro-electric charges however may lead to premature lasing. We manufactured and characterized temperature-stable LN Q-switch. A thermo-chemical anneal was performed creating a conductive material layer 0.5mm thick with increased conductivity. While this increases optical insertion loss by a few percent, this is tolerable in high gain lasers. We present details of treatment, the surface charge creation and dissipation mechanism and the setup used to assess the cold-performance used to demonstrate improved charge dissipation when compared to untreated crystals.

  8. Parameter Analysis For A High-Gain Harmonic Generation FEL By Numerical Calculation Based On 1D Theory

    CERN Document Server

    Li, Yuhui; Zhang, Shancai

    2004-01-01

    The high-gain harmonic generation (HGHG) free-electron laser (FEL) is an important candidate for a fourth-generation light source. Lots of theoretical work has been performed. Recently a further 1D theory about HGHG FEL has been developed. It considers the effects of different parameters for the whole process. An initial program based on this theory has been made. In this paper, a brief comparison of the results from this 1D program and from TDA (3D code) is discussed. It also analyses the parameters for Shanghai deep ultra violate free-electron laser source (SDUV-FEL), including electron beam energy spread, seed laser power, strength of dispersion section etc.

  9. Laser propagation through full-scale, high-gain MagLIF gas pipes using the NIF

    Science.gov (United States)

    Pollock, Bradley; Sefkow, Adam; Goyon, Clement; Strozzi, David; Khan, Shahab; Rosen, Mordy; Campbell, Mike; Logan, Grant; Peterson, Kyle; Moody, John

    2016-10-01

    The first relevant measurements of laser propagation through surrogate high-gain MagLIF gas pipe targets at full scale have been performed at the NIF, using 30 kJ of laser drive from one quad in a 10 ns pulse at an intensity of 2e14 W/cm2. The unmagnetized pipe is filled with 1 atm of 99%/1% neopentane/Ar, and uses an entrance window of 0.75 um polyimide and an exit window of 0.3 um of Ta backed with 5 um of polyimide. Side-on x-ray emission from the plasma is imaged through the 100 um-thick epoxy wall onto a framing camera at four times during the drive, and is in excellent agreement with pre-shot HYDRA radiation-hydrodynamics modeling. X-ray emission from the Ta exit plane is imaged onto a streak camera to determine the timing and intensity of the laser burning through the pipe, and the Ar emission from the center of the pipe is spectrally- and temporally-resolved to determine the plasma electron temperature. Backscatter is measured throughout the laser drive, and is found to be of significance only when the laser reaches the Ta exit plane and produces SBS. These first results in unmagnetized surrogate gas fills are encouraging since they demonstrate sufficient laser energy absorption and low LPI losses within high-density long-scale-length plasmas for proposed high-gain MagLIF target designs. We will discuss plans to magnetize targets filled with high-density DT gas in future experiments. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the National Nuclear Security Administration under Contract No. DE-AC04-94AL85000.

  10. Electron beam diagnostic for profiling high power beams

    Science.gov (United States)

    Elmer, John W [Danville, CA; Palmer, Todd A [Livermore, CA; Teruya, Alan T [Livermore, CA

    2008-03-25

    A system for characterizing high power electron beams at power levels of 10 kW and above is described. This system is comprised of a slit disk assembly having a multitude of radial slits, a conducting disk with the same number of radial slits located below the slit disk assembly, a Faraday cup assembly located below the conducting disk, and a start-stop target located proximate the slit disk assembly. In order to keep the system from over-heating during use, a heat sink is placed in close proximity to the components discussed above, and an active cooling system, using water, for example, can be integrated into the heat sink. During use, the high power beam is initially directed onto a start-stop target and after reaching its full power is translated around the slit disk assembly, wherein the beam enters the radial slits and the conducting disk radial slits and is detected at the Faraday cup assembly. A trigger probe assembly can also be integrated into the system in order to aid in the determination of the proper orientation of the beam during reconstruction. After passing over each of the slits, the beam is then rapidly translated back to the start-stop target to minimize the amount of time that the high power beam comes in contact with the slit disk assembly. The data obtained by the system is then transferred into a computer system, where a computer tomography algorithm is used to reconstruct the power density distribution of the beam.

  11. Ion energy characteristics downstream of a high power helicon

    Energy Technology Data Exchange (ETDEWEB)

    Prager, James; Winglee, Robert; Ziemba, Tim; Roberson, B Race; Quetin, Gregory [University of Washington, Johnson Hall 070, Box 351310, 4000 15th Avenue NE, Seattle, WA 98195-1310 (United States)], E-mail: jprager@u.washington.edu

    2008-05-01

    The High Power Helicon eXperiment operates at higher powers (37 kW) and lower background neutral pressure than other helicon experiments. The ion velocity distribution function (IVDF) has been measured at multiple locations downstream of the helicon source and a mach 3-6 flowing plasma was observed. The helicon antenna has a direct effect in accelerating the plasma downstream of the source. Also, the IVDF is affected by the cloud of neutrals from the initial gas puff, which keeps the plasma speed low at early times near the source.

  12. Diversion assumptions for high-powered research reactors

    Energy Technology Data Exchange (ETDEWEB)

    Binford, F.T.

    1984-01-01

    This study deals with diversion assumptions for high-powered research reactors -- specifically, MTR fuel; pool- or tank-type research reactors with light-water moderator; and water, beryllium, or graphite reflectors, and which have a power level of 25 MW(t) or more. The objective is to provide assistance to the IAEA in documentation of criteria and inspection observables related to undeclared plutonium production in the reactors described above, including: criteria for undeclared plutonium production, necessary design information for implementation of these criteria, verification guidelines including neutron physics and heat transfer, and safeguards measures to facilitate the detection of undeclared plutonium production at large research reactors.

  13. High power test of a 30 GHz planar accelerator

    CERN Document Server

    Braun, Hans Heinrich; Henke, H; Wuensch, Walter; Yu, D

    2001-01-01

    A 30-GHz muffin-tin, traveling-wave accelerating structure consisting of 37 cells was tested at high power using the CTF2 at CERN. The structure was fabricated with conventional milling and brazing, including tuning holes at cavity roofs. No special surface preparation or treatment was done to the structure. A maximum peak power in excess of 100 MW at a pulse width of 4 ns was transported through the structure before electron bursts were initiated. A maximum accelerating gradient of 60 MV/m was achieved with a peak RF power of 40 MW at a pulse width of 8 ns.

  14. Novel design for a high power superconducting delay line

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.J.; Caporaso, G.J.

    1997-05-08

    Potential designs for a high power superconducting delay line of approximately 10ms duration are described. The transmitted signal should have low dispersion and little attenuation to recapture the original signal. Such demands cannot be met using conventional metal conductors. This paper outlines a proposal for a new transmission line design using low temperature superconducting material which meets system specifications. The 25W line is designed to carry pulsed signals with an approximate rise time of 8 nsec and a maximum voltage of 25kV. Predicted electrical design and performance of the line is presented.

  15. Designs for a high power superconducting delay line

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.J.; Caporaso, G.

    1997-06-26

    Potential designs for a high power superconducting delay line of approximately 10 microsecs duration are described. The transmitted signal should have low dispersion and little attenuation to recapture the original signal. Such demands cannot be met using conventional metal conductors. This paper outlines a proposal for a new transmission line design using low temperature superconducting material which meets system specifications. The 25 omega line is designed to carry pulsed signals with an approximate rise time of 8 nsec and a maximum voltage magnitude of 25 kV. Predicted electrical design and performance of the line will be presented.

  16. Discharge current modes of high power impulse magnetron sputtering

    Directory of Open Access Journals (Sweden)

    Zhongzhen Wu

    2015-09-01

    Full Text Available Based on the production and disappearance of ions and electrons in the high power impulse magnetron sputtering plasma near the target, the expression of the discharge current is derived. Depending on the slope, six possible modes are deduced for the discharge current and the feasibility of each mode is discussed. The discharge parameters and target properties are simplified into the discharge voltage, sputtering yield, and ionization energy which mainly affect the discharge plasma. The relationship between these factors and the discharge current modes is also investigated.

  17. Coherent combination of high-power, zigzag slab lasers

    Science.gov (United States)

    Goodno, G. D.; Komine, H.; McNaught, S. J.; Weiss, S. B.; Redmond, S.; Long, W.; Simpson, R.; Cheung, E. C.; Howland, D.; Epp, P.; Weber, M.; McClellan, M.; Sollee, J.; Injeyan, H.

    2006-05-01

    We demonstrate a scalable architecture for a high-power, high-brightness, solid-state laser based on coherent combinations of master oscillator power amplifier chains. A common master oscillator injects a sequence of multikilowatt Nd:YAG zigzag slab amplifiers. Adaptive optics correct the wavefront of each amplified beamlet. The beamlets are tiled side by side and actively phase locked to form a single output beam. The laser produces 19 kW with beam quality <2× diffraction limited. To the best of our knowledge, this is the brightest cw solid-state laser demonstrated to date.

  18. Using high-power light emitting diodes for photoacoustic imaging

    DEFF Research Database (Denmark)

    Hansen, René Skov

    The preliminary result of using a high-power light emitting diode, LED, for photoacoustic imaging is presented. The pulsed light source is created by a 1Watt red Luxeon LED. The LED delivers light pulses with 25W peak power when supplied by 40A peak, 60ns wide current pulses. The phantom used...... for the experiment consists of a 3mm high x 5mm wide slice of green colored gelatine overlaid by a 3cm layer of colorless gelatine. The light pulses from the LED is focused on the green gelatine. The photoacoustic response from the green gelatine is detected by a single transducer on the opposite (top) surface...

  19. Microfabricated Millimeter-Wave High-Power Vacuum Electronic Amplifiers

    Science.gov (United States)

    2015-01-01

    colin.joye@nrl.navy.mil Microfabricated Millimeter-Wave High-Power Vacuum Electronic Amplifiers Figure 2. Results from the 220 GHz TWT . (a) Small signal...Completed tube under hot test. 220 GHz TWT Demonstration The 220 GHz TWT device was based on spare parts from a commercially available CPI VKY2444T G...existing parts, our TWT bested this COTS EIK performance by a factor of 12x in power and 50x in bandwidth for the same size, weight and prime power

  20. High power composite cavity fiber laser oscillator at 1120 nm

    Science.gov (United States)

    Wang, Jianming; Li, Cheng; Yan, Dapeng

    2017-12-01

    A high power composite cavity fiber laser oscillator at 1120 nm is demonstrated experimentally. Performances of the 1120 nm single fiber laser oscillator and the composite cavity are investigated and compared, and the parasitic oscillation created by the strong amplified spontaneous emission (ASE) can be suppressed effectively in the composite cavity scheme. 2.04-kW 1120-nm signal light with a good beam quality (M2=1.15) is obtained, and the optical conversion efficiency of the composite cavity fiber laser oscillator is about 63% in the experiment. The compact architecture of composite cavity provides an effective scheme for power scaling of long wavelength lasers.

  1. Theory and Modeling of High-Power Gyrotrons

    Energy Technology Data Exchange (ETDEWEB)

    Nusinovich, Gregory Semeon [Univ. of Maryland, College Park, MD (United States)

    2016-04-29

    This report summarized results of the work performed at the Institute for Research in Electronics and Applied Physics of the University of Maryland (College Park, MD) in the framework of the DOE Grant “Theory and Modeling of High-Power Gyrotrons”. The report covers the work performed in 2011-2014. The research work was performed in three directions: - possibilities of stable gyrotron operation in very high-order modes offering the output power exceeding 1 MW level in long-pulse/continuous-wave regimes, - effect of small imperfections in gyrotron fabrication and alignment on the gyrotron efficiency and operation, - some issues in physics of beam-wave interaction in gyrotrons.

  2. ELBE Center for High-Power Radiation Sources

    Directory of Open Access Journals (Sweden)

    Peter Dr. Michel

    2016-01-01

    Full Text Available In the ELBE Center for High-Power Radiation Sources, the superconducting linear electron accelerator ELBE, serving  two free electron lasers, sources for intense coherent THz radiation, mono-energetic positrons, electrons, γ-rays, a neutron time-of-flight system as well as two synchronized ultra-short pulsed Petawatt laser systems are collocated. The characteristics of these beams make the ELBE center a unique research instrument for a variety of external users in fields ranging from material science over nuclear physics to cancer research, as well as scientists of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR.

  3. High power RF solid state power amplifier system

    Science.gov (United States)

    Sims, III, William Herbert (Inventor); Chavers, Donald Gregory (Inventor); Richeson, James J. (Inventor)

    2011-01-01

    A high power, high frequency, solid state power amplifier system includes a plurality of input multiple port splitters for receiving a high-frequency input and for dividing the input into a plurality of outputs and a plurality of solid state amplifier units. Each amplifier unit includes a plurality of amplifiers, and each amplifier is individually connected to one of the outputs of multiport splitters and produces a corresponding amplified output. A plurality of multiport combiners combine the amplified outputs of the amplifiers of each of the amplifier units to a combined output. Automatic level control protection circuitry protects the amplifiers and maintains a substantial constant amplifier power output.

  4. Charging-discharging system with high power factor, high efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun Soo; Joe, Kee Yeon; Byun, Young Bok; Koo, Heun Hoi [Korea Electrotechnology Research Institute (Korea, Republic of)

    1995-07-01

    This paper presents equipment for charging and discharging with high power factor and high efficiency. This equipment is consisted of 3{Phi} SPWM AC/DC converter for improving input current waveform and input power factor, and bidirectional DC/DC converter for electric isolation in the DC link Part. Therefore, Input power factor and the total efficiency in the proposed system can be increased more than in the conventional phase-controlled thyristor charging-discharging System. (author). 7 refs., 14 figs., 1 tab.

  5. Towards quantitative simulations of high power proton cyclotrons

    Directory of Open Access Journals (Sweden)

    Y. J. Bi

    2011-05-01

    Full Text Available We describe a large scale simulation effort using Object Oriented Parallel Accelerator Library, that leads to a better quantitative understanding of the existing Paul Scherrer Institut high power proton cyclotron facility. The 1.3 MW of beam power on target poses stringent constraints on the controlled and uncontrolled beam losses. We present initial conditions for the Ring simulation, obtained from the new time-structure measurement and the many profile monitors of the 72 MeV transfer line. A trim coil model is developed, including trim coil TC15, which is needed to avoid the dangerous ν_{r}=2ν_{z} resonance. By properly selecting the injection position and angle (eccentric injection, the flattop voltage, and phase, very good agreement between simulations and measurements at the radial probe RRE4 is obtained. We report on 3–4 orders of magnitude in dynamic range when comparing simulations with measurements. The relation between beam intensity, rms beam size, and accelerating voltage is studied and compared with measurement. The demonstrated capabilities are mandatory in the design and operation of the next generation high power proton drivers. In an outlook we discuss our future plans to include more physics into the model, which eventually leads to an even larger dynamic range in the simulation.

  6. High power RF systems for the BNL ERL project

    Energy Technology Data Exchange (ETDEWEB)

    Zaltsman, A.; Lambiase, R.

    2011-03-28

    The Energy Recovery Linac (ERL) project, now under construction at Brookhaven National Laboratory, requires two high power RF systems. The first RF system is for the 703.75 MHz superconducting electron gun. The RF power from this system is used to drive nearly half an Ampere of beam current to 2 MeV. There is no provision to recover any of this energy so the minimum amplifier power is 1 MW. It consists of 1 MW CW klystron, transmitter and power supplies, 1 MW circulator, 1 MW dummy load and a two-way power splitter. The second RF system is for the 703.75 MHz superconducting cavity. The system accelerates the beam to 54.7 MeV and recovers this energy. It will provide up to 50 kW of CW RF power to the cavity. It consists of 50 kW transmitter, circulator, and dummy load. This paper describes the two high power RF systems and presents the test data for both.

  7. Numerical simulation of high power LED heat-dissipating system

    Science.gov (United States)

    Wu, Shih-Jeh; Hsu, Hsiang-Chen; Fu, Shen-Li; Yeh, Jiam-Nan

    2014-03-01

    In this paper, thermal analysis of the heat dissipation under different heat sink for high-power white Light Emitting Diode (LED) is presented. Junction temperature of LED is elevated as the power of LED increases, which brings up deterioration of light efficiency and other side effects. Heat dissipation is another design concern other than material and illumination efficiency. The purpose of this paper is to investigate the cooling of high-power LED chips and modules for design of heat sinks. Three types of heat sinks are designed for a tandem 12-chip module and an extensive numerical investigation of the heat sink design performance is conducted by Computational Fluid Dynamics software Fluent. The effects of heat sink geometry and adhesive material are also investigated. Design variables are the thickness of sink base, number, thickness and length of fins. The total wetted area is the dominant factor to the junction temperature. The objective of design regarding the junction temperatures around 50°C is easily achieved. However, its effect is limited at high values of these parameters, furthermore an excessive number of fins incurs reverse consequence due to problem of ventilation also waste of material.

  8. High power density proton exchange membrane fuel cells

    Science.gov (United States)

    Murphy, Oliver J.; Hitchens, G. Duncan; Manko, David J.

    1993-01-01

    Proton exchange membrane (PEM) fuel cells use a perfluorosulfonic acid solid polymer film as an electrolyte which simplifies water and electrolyte management. Their thin electrolyte layers give efficient systems of low weight, and their materials of construction show extremely long laboratory lifetimes. Their high reliability and their suitability for use in a microgravity environment makes them particularly attractive as a substitute for batteries in satellites utilizing high-power, high energy-density electrochemical energy storage systems. In this investigation, the Dow experimental PEM (XUS-13204.10) and unsupported high platinum loading electrodes yielded very high power densities, of the order of 2.5 W cm(exp -2). A platinum black loading of 5 mg per cm(exp 2) was found to be optimum. On extending the three-dimensional reaction zone of fuel cell electrodes by impregnating solid polymer electrolyte into the electrode structures, Nafion was found to give better performance than the Dow experimental PEM. The depth of penetration of the solid polymer electrolyte into electrode structures was 50-70 percent of the thickness of the platinum-catalyzed active layer. However, the degree of platinum utilization was only 16.6 percent and the roughness factor of a typical electrode was 274.

  9. Optical Fiber for High-Power Optical Communication

    Directory of Open Access Journals (Sweden)

    Kenji Kurokawa

    2012-09-01

    Full Text Available We examined optical fibers suitable for avoiding such problems as the fiber fuse phenomenon and failures at bends with a high power input. We found that the threshold power for fiber fuse propagation in photonic crystal fiber (PCF and hole-assisted fiber (HAF can exceed 18 W, which is more than 10 times that in conventional single-mode fiber (SMF. We considered this high threshold power in PCF and HAF to be caused by a jet of high temperature fluid penetrating the air holes. We showed examples of two kinds of failures at bends in conventional SMF when the input power was 9 W. We also observed the generation of a fiber fuse under a condition that caused a bend-loss induced failure. We showed that one solution for the failures at bends is to use optical fibers with a low bending loss such as PCF and HAF. Therefore, we consider PCF and HAF to be attractive solutions to the problems of the fiber fuse phenomenon and failures at bends with a high power input.

  10. High-power disk lasers based on dilute nitride heterostructures

    Science.gov (United States)

    Guina, M.; Leinonen, T.; Härkönen, A.; Pessa, M.

    2009-12-01

    We report the development of InGaAsN-based gain mirrors for high-power optically pumped semiconductor disk lasers with direct emission at wavelengths around 1180 nm. The gain mirrors were fabricated by molecular beam epitaxy. They consist of 10 dilute nitride quantum wells, which were placed within a GaAs micro-cavity on top of a GaAs/AlAs distributed Bragg reflector. We demonstrated laser operation at ~1180 nm with record high output power (~7 W). The differential efficiency was ~30% for operation at 5 °C and ~28% when operating at 15 °C. The lasers exhibited excellent tuning characteristics, delivering an output power of more than 5 W in a narrow spectrum and providing over 30 nm tuning band. These features represent significant progress towards demonstration of practical high-power lasers with frequency-doubled yellow emission required for laser guide stars, life sciences and spectroscopy. At the same time the results emphasize the importance of dilute nitride heterostructures in the development of novel optoelectronic devices.

  11. Spallation Neutron Source High Power RF Installation and Commissioning Progress

    CERN Document Server

    McCarthy, Michael P; Bradley, Joseph T; Fuja, Ray E; Gurd, Pamela; Hardek, Thomas; Kang, Yoon W; Rees, Daniel; Roybal, William; Young, Karen A

    2005-01-01

    The Spallation Neutron Source (SNS) linac will provide a 1 GeV proton beam for injection into the accumulator ring. In the normal conducting (NC) section of this linac, the Radio Frequency Quadupole (RFQ) and six drift tube linac (DTL) tanks are powered by seven 2.5 MW, 402.5 MHz klystrons and the four coupled cavity linac (CCL) cavities are powered by four 5.0 MW, 805 MHz klystrons. Eighty-one 550 kW, 805 MHz klystrons each drive a single cavity in the superconducting (SC) section of the linac. The high power radio frequency (HPRF) equipment was specified and procured by LANL and tested before delivery to ensure a smooth transition from installation to commissioning. Installation of RF equipment to support klystron operation in the 350-meter long klystron gallery started in June 2002. The final klystron was set in place in September 2004. Presently, all RF stations have been installed and high power testing has been completed. This paper reviews the progression of the installation and testing of the HPRF Sys...

  12. Test Facilities in Support of High Power Electric Propulsion Systems

    Science.gov (United States)

    van Dyke, Melissa; Houts, Mike; Godfroy, Thomas; Dickens, Ricky; Martin, James J.; Salvail, Patrick; Carter, Robert

    2003-01-01

    Successful development of space fission systems requires an extensive program of affordable and realistic testing. In addition to tests related to design/development of the fission system, realistic testing of the actual flight unit must also be performed. If the system is designed to operate within established radiation damage and fuel burn up limits while simultaneously being designed to allow close simulation of heat from fission using resistance heaters, high confidence in fission system performance and lifetime can be attained through non-nuclear testing. Through demonstration of systems concepts (designed by DOE National Laboratories) in relevant environments, this philosophy has been demonstrated through hardware testing in the High Power Propulsion Thermal Simulator (HPPTS). The HPPTS is designed to enable very realistic non-nuclear testing of space fission systems. Ongoing research at the HPPTS is geared towards facilitating research, development, system integration, and system utilization via cooperative efforts with DOE labs, industry, universities, and other NASA centers. Through hardware based design and testing, the HPPTS investigates High Power Electric Propulsion (HPEP) component, subsystem, and integrated system design and performance.

  13. Single-stage electronic ballast with high-power factor

    Science.gov (United States)

    Park, Chun-Yoon; Kwon, Jung-Min; Kwon, Bong-Hwan

    2014-03-01

    This article proposes a single-stage electronic ballast circuit with high-power factor. The proposed circuit was derived by sharing the switches of the power factor correction (PFC) and the half-bridge LCC resonant inverter. This integration of switches forms the proposed single-stage electronic ballast, which provides an almost unity power factor and a ripple-free input current by using a coupled inductor without increasing the voltage stress. In addition, it realises zero-voltage-switching (ZVS) by employing the self-oscillation technique. The saturable transformer constituting the self-oscillating drive limits the lamp current and dominates the switching frequency of the ballast. Therefore, the proposed single-stage ballast has the advantage of high-power factor, high efficiency, low cost and high reliability. Steady-state analysis of the PFC and the half-bridge LCC resonant inverter are described. The results of experiments performed using a 30 W fluorescent lamp are also presented to confirm the performance of the proposed ballast.

  14. Three-Phase High-Power and Zero-Current-Switching OBC for Plug-In Electric Vehicles

    OpenAIRE

    Cheng-Shan Wang; Wei Li; Zhun Meng; Yi-Feng Wang; Jie-Gui Zhou

    2015-01-01

    In this paper, an interleaved high-power zero-current-switching (ZCS) onboard charger (OBC) based on the three-phase single-switch buck rectifier is proposed for application to plug-in electric vehicles (EVs). The multi-resonant structure is used to achieve high efficiency and high power density, which are necessary to reduce the volume and weight of the OBC. This study focuses on the border conditions of ZCS converting with a battery load, which means the variation ranges of the output volta...

  15. Review of high-power pulsed systems at the Institute of High Current Electronics

    Directory of Open Access Journals (Sweden)

    A.A. Kim

    2016-07-01

    Full Text Available In this paper, we give a review of some most powerful pulsed systems developed at the Institute of High Current Electronics (HCEI, Siberian Branch, Russian Academy of Sciences, and describe latest achievements of the teams dealing with these installations. Besides the presented high-power systems, HCEI performs numerous investigations using much less powerful generators. For instance, last year much attention was paying to the research and development of the intense low-energy (<200 kV high-current electron and ion beam and plasma sources, and their application in the technology [1–3].

  16. Fiber optic vibration sensor for high-power electric machines realized using 3D printing technology

    Science.gov (United States)

    Igrec, Bojan; Bosiljevac, Marko; Sipus, Zvonimir; Babic, Dubravko; Rudan, Smiljko

    2016-03-01

    The objective of this work was to demonstrate a lightweight and inexpensive fiber-optic vibration sensor, built using 3D printing technology, for high-power electric machines and similar applications. The working principle is based on modulating the light intensity using a blade attached to a bendable membrane. The sensor prototype was manufactured using PolyJet Matrix technology with DM 8515 Grey 35 Polymer. The sensor shows linear response, expected bandwidth (< 150 Hz), and from our measurements we estimated the damping ratio for used polymer to be ζ ≍ 0.019. The developed prototype is simple to assemble, adjust, calibrate and repair.

  17. Experimental and theoretical analysis of an optical current sensor for high power systems

    Science.gov (United States)

    Brigida, A. C. S.; Nascimento, I. M.; Mendonça, S.; Costa, J. C. W. A.; Martinez, M. A. G.; Baptista, J. M.; Jorge, P. A. S.

    2013-03-01

    A magneto-optical sensor, using a dual quadrature polarimetric processing scheme, was evaluated for current metering and protection applications in high voltage lines. Sensor calibration and resolution were obtained in different operational conditions using illumination in the 1550-nm band. Results obtained indicated the feasibility of interrogating such sensor via the optical ground wire (OPGW) link installed in standard high power grids. The polarimetric bulk optical current sensor also was theoretically studied, and the effects of different sources of error considering practical deployment were evaluated. In particular, the interference from external magnetic fields in a tree-phase system was analyzed.

  18. The development of recent high-power ultrasonic transducers for Near-well ultrasonic processing technology.

    Science.gov (United States)

    Wang, Zhenjun; Xu, Yuanming

    2017-07-01

    With the reduction of crude oil throughout the world, enhance oil recovery technology has become a major oil research topics, which can greatly increase the recovery ratio of the crude oil before the dawning of renewable energy era. Near-well ultrasonic processing technology, as one new method, has attracted more attention for Enhanced Oil Recovery due to its low cost, good applicability and no environmental pollution in recent rears. There are two important relevant aspects about Near-well ultrasonic processing technology: (a) how to enhance the oil flow through the rocks into the pumping pool and (b) how to reduce the oil viscosity so that it can be easier to pump. Therefore, how to design a high-power ultrasonic equipment with excellent performance is crucial for Near-well ultrasonic processing technology. In this paper, recent new high-power ultrasonic transducers for Near-well ultrasonic processing technology are summarized. Each field application of them are also given. The purpose of this paper is to provide reference for the further development of Near-well ultrasonic processing technology. With the reduction of crude oil throughout the world, enhance oil recovery technology has become a major oil research topics, which can greatly increase the recovery ratio of the crude oil before the dawning of renewable energy era. Near-well ultrasonic processing technology, as one new method, has attracted more attention for Enhanced Oil Recovery due to its low cost, good applicability and no environmental pollution in recent rears. There are two important relevant aspects about Near-well ultrasonic processing technology: (a) how to enhance the oil flow through the rocks into the pumping pool and (b) how to reduce the oil viscosity so that it can be easier to pump. Therefore, how to design a high-power ultrasonic equipment with excellent performance is crucial for Near-well ultrasonic processing technology. In this paper, recent new high-power ultrasonic transducers

  19. Utilization of recently developed codes for high power Brayton and Rankine cycle power systems

    Science.gov (United States)

    Doherty, Michael P.

    1993-01-01

    Two recently developed FORTRAN computer codes for high power Brayton and Rankine thermodynamic cycle analysis for space power applications are presented. The codes were written in support of an effort to develop a series of subsystem models for multimegawatt Nuclear Electric Propulsion, but their use is not limited just to nuclear heat sources or to electric propulsion. Code development background, a description of the codes, some sample input/output from one of the codes, and state future plans/implications for the use of these codes by NASA's Lewis Research Center are provided.

  20. Unified zero-current-transition techniques for high-power three-phase PWM inverters

    OpenAIRE

    Li, Yong

    2002-01-01

    This dissertation is devoted to a unified and comprehensive study of zero-current-transition (ZCT) soft-switching techniques for high-power three-phase PWM inverter applications. Major efforts in this study are as follows: 1) Conception of one new ZCT scheme and one new ZCT topology; 2) Systematic comparison of a family of ZCT inverters; 3) Design, implementation and experimental evaluation of two 55-kW prototype inverters for electric vehicle (EV) motor drives that are developed based on the...

  1. Design of a High-Power White Light Source with Colloidal Quantum Dots and Non-Rare-Earth Phosphors

    Science.gov (United States)

    Bicanic, Kristopher T.

    This thesis describes the design process of a high-power white light source, using novel phosphor and colloidal quantum dot materials. To incorporate multiple light emitters, we generalized and extended a down-converting layer model. We employed a phosphor mixture comprising of YAG:Ce and K2TiF 6:Mn4+ powders to illustrate the effectiveness of the model. By incorporating experimental photophysical results from the phosphors and colloidal quantum dots, we modeled our system and chose the design suitable for high-power applications. We report a reduction in the correlated color temperature by 600K for phosphor and quantum dot systems, enabling the creation of a warm white light emission at power densities up to 5 kW/cm 2. Furthermore, at this high-power, their emission achieves the digital cinema initiative (DCI) requirements with a luminescence efficacy improvement up to 32% over the stand-alone ceramic YAG:Ce phosphor.

  2. Development and Qualification of an Antenna Pointing Mechanism for the ExoMars High-Gain Antenna

    Science.gov (United States)

    St-Andre, Stephane; Dumais, Marie-Christine; Lebel, Louis-Philippe; Langevin, Jean-Paul; Horth, Richard; Winton, Alistair; Lebleu, Denis

    2015-09-01

    The European Space Agency ExoMars 2016 mission required a gimbaled High Gain Antenna (HGA) for orbiter-to-earth communications. The ExoMars Program is a cooperative program between ESA and ROSCOSMOS with participation of NASA. The ExoMars Program industrial consortium is led by THALES ALENIA SPACE.This paper presents the design and qualification test results of the Antenna Pointing Mechanism (APM) used to point the HGA towards Earth. This electrically redundant APM includes motors, drive trains, optical encoders, cable cassette and RF Rotary Joints.Furthermore, the paper describes the design, development and the qualification approach applied to this APM. The design challenges include a wide pointing domain necessary to maximise the communication duty cycle during the early operation phase, the interplanetary cruise phase and during the mission’s orbital science phase. Other design drivers are an extended rotation cycle life with very low backlash yielding little wear and accurate position feedback on both axes. Major challenges and related areas of development include:• Large moments are induced on the APM due to aerobraking forces when the Mars atmosphere is used to slow the orbiter into its science mission orbit,• Thermal control of the critical components of the APM due to the different environments of the various phases of the mission. Also, the large travel range of the actuators complicated the radiator design in order to maintain clearances and to avoid overheating.• The APM, with a mass less than 17.5 kg, is exposed to a demanding dynamic environment due to its mounting on the spacecraft thrust tube and aggravated by its elevated location on the payload.• Power and Data transmission between elevation and azimuth axes through a compact large rotation range spiral type cable cassette.• Integration of a 16 bit redundant encoder on both axes for position feedback: Each encoder is installed on the back of a rotary actuator and is coupled using the

  3. Efficient Tm-Fiber-Pumped Ho:YLF Laser System for Coherent LIDAR Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to employ a recently developed, efficient, high-power, heavily-doped Tm:silica-fiber technology as a high-gain fiber pre-amplifier and as a...

  4. High Power, Repetitive, Stacked Blumlein Pulse Generators Commuted by a Single Switching Element

    Science.gov (United States)

    Bhawalkar, Jayant Dilip

    In this work, the stacked Blumlein pulsers developed at the University of Texas at Dallas were characterized and shown to be versatile sources of pulse power for a variety of applications. These devices consisted of several triaxial Blumleins stacked in series at one end. The lines were charged in parallel and synchronously commuted repetitively with a single switching element at the other end. In this way, relatively low charging voltages were multiplied to give a high discharge voltage across an arbitrary load without the need for complex Marx bank circuitry. Several pulser parameters such as the number of stacked Blumlein lines, line configuration, type of switching element, and the length of the lines, were varied and the waveform characteristics were observed and analyzed. It was shown that these devices are capable of generating fast rising waveforms with a wide range of peak voltage and current values. The generation of high power waveforms with pulse durations in the range of 80-600 ns was demonstrated without degradation of the voltage gains. The results of this work indicated that unlike generators based on stacked transmission lines, the effects of parasitic modes were not appreciable for the stacked Blumlein pulsers. Opportunities for tactically packaging these pulsers were also investigated and a significant reduction in their size and weight was demonstrated. For this, dielectric lifetime and Blumlein spacing studies were performed on small scale prototypes. In addition to production of intense X-ray pulses, the possible applications for these novel pulsers include driving magnetrons for high power microwave generation, pumping laser media, or powering e-beam diodes. They could also serve as compact, tabletop sources of high power pulses for various research experiments.

  5. High power continuous-wave dual-wavelength alexandrite laser

    Science.gov (United States)

    Ghanbari, Shirin; Major, Arkady

    2017-10-01

    A high power dual-wavelength alexandrite (Cr:BeAl2O4) laser using a single plate birefringent filter (BRF) was demonstrated. Using a 6 mm thick BRF, dual-wavelength output at 745.2 nm and 756.2 nm (5.9 THz of frequency difference) with 850 mW of average output power was achieved as well as with 16.8% optical-to-optical and 24.2% slope efficiency. The tunability of dual-wavelength separation was also demonstrated by employing the 4 mm and 2 mm thick BRFs with similar output powers. To the best of our knowledge, this is the first demonstration of a dual-wavelength alexandrite laser.

  6. High-power laser experiments to study collisionless shock generation

    Directory of Open Access Journals (Sweden)

    Sakawa Y.

    2013-11-01

    Full Text Available A collisionless Weibel-instability mediated shock in a self-generated magnetic field is studied using two-dimensional particle-in-cell simulation [Kato and Takabe, Astophys. J. Lett. 681, L93 (2008]. It is predicted that the generation of the Weibel shock requires to use NIF-class high-power laser system. Collisionless electrostatic shocks are produced in counter-streaming plasmas using Gekko XII laser system [Kuramitsu et al., Phys. Rev. Lett. 106, 175002 (2011]. A NIF facility time proposal is approved to study the formation of the collisionless Weibel shock. OMEGA and OMEGA EP experiments have been started to study the plasma conditions of counter-streaming plasmas required for the NIF experiment using Thomson scattering and to develop proton radiography diagnostics.

  7. High Power Operation of the JLab IR FEL Driver Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Beard; Stephen Benson; George Biallas; James Boyce; Donald Bullard; James Coleman; David Douglas; H. Dylla; Richard Evans; Pavel Evtushenko; Christopher Gould; Albert Grippo; Joseph Gubeli; David Hardy; Carlos Hernandez-Garcia; J. Hovater; Kevin Jordan; John Klopf; Rui Li; Steven Moore; George Neil; Benard Poelker; Thomas Powers; Joseph Preble; Robert Rimmer; Daniel Sexton; Michelle D. Shinn; Christopher Tennant; Richard Walker; Gwyn Williams; Shukui Zhang

    2007-08-01

    Operation of the JLab IR Upgrade FEL at CW powers in excess of 10 kW requires sustained production of high electron beam powers by the driver ERL. This in turn demands attention to numerous issues and effects, including: cathode lifetime; control of beamline and RF system vacuum during high current operation; longitudinal space charge; longitudinal and transverse matching of irregular/large volume phase space distributions; halo management; management of remnant dispersive effects; resistive wall, wake-field, and RF heating of beam vacuum chambers; the beam break up instability; the impact of coherent synchrotron radiation (both on beam quality and the performance of laser optics); magnetic component stability and reproducibility; and RF stability and reproducibility. We discuss our experience with these issues and describe the modus vivendi that has evolved during prolonged high current, high power beam and laser operation.

  8. Liquid state DNP using a 260 GHz high power gyrotron.

    Science.gov (United States)

    Denysenkov, Vasyl; Prandolini, Mark J; Gafurov, Marat; Sezer, Deniz; Endeward, Burkhard; Prisner, Thomas F

    2010-06-14

    Dynamic nuclear polarization (DNP) at high magnetic fields (9.2 T, 400 MHz (1)H NMR frequency) requires high microwave power sources to achieve saturation of the EPR transitions. Here we describe the first high-field liquid-state DNP results using a high-power gyrotron microwave source (20 W at 260 GHz). A DNP enhancement of -29 on water protons was obtained for an aqueous solution of Fremy's Salt; in comparison the previous highest value was -10 using a solid-state microwave power source (maximum power 45 mW). The increased enhancements are partly due to larger microwave saturation and elevated sample temperature. These experimentally observed DNP enhancements, which by far exceed the predicted values extrapolated from low-field DNP experiments, demonstrate experimentally that DNP is possible in the liquid state also at high magnetic fields.

  9. High power RF window deposition apparatus, method, and device

    Science.gov (United States)

    Ives, Lawrence R.; Lucovsky, Gerald; Zeller, Daniel

    2017-07-04

    A process for forming a coating for an RF window which has improved secondary electron emission and reduced multipactor for high power RF waveguides is formed from a substrate with low loss tangent and desirable mechanical characteristics. The substrate has an RPAO deposition layer applied which oxygenates the surface of the substrate to remove carbon impurities, thereafter has an RPAN deposition layer applied to nitrogen activate the surface of the substrate, after which a TiN deposition layer is applied using Titanium tert-butoxide. The TiN deposition layer is capped with a final RPAN deposition layer of nitridation to reduce the bound oxygen in the TiN deposition layer. The resulting RF window has greatly improved titanium layer adhesion, reduced multipactor, and is able to withstand greater RF power levels than provided by the prior art.

  10. High-power extreme ultraviolet source based on gas jets

    Energy Technology Data Exchange (ETDEWEB)

    Kubiak, G.D.; Bernardez, L.J.; Krenz, K.

    1998-03-01

    The authors report on the development of a high power laser plasma Extreme Ultraviolet (EUV) source for Extreme Ultraviolet Lithography. The source is based on the plasma emission of a recycled jet beam of large Xe clusters and produces no particulate debris. The source will be driven by a pulsed laser delivering 1,500 W of focused average power to the cluster jet target. To develop condensers and to optimize source performance, a low power laboratory cluster jet prototype has been used to study the spectroscopy, angular distributions, and EUV source images of the cluster jet plasma emission. In addition, methods to improve the reflectance lifetimes of nearby plasma facing condenser mirrors have been developed. The resulting source yields EUV conversion efficiencies up to 3.8% and mirror lifetimes of 10{sup 9} plasma pulses.

  11. Thermal management methods for compact high power LED arrays

    Science.gov (United States)

    Christensen, Adam; Ha, Minseok; Graham, Samuel

    2007-09-01

    The package and system level temperature distributions of a high power (>1W) light emitting diode (LED) array has been investigated using numerical heat flow models. For this analysis, a thermal resistor network model was combined with a 3D finite element submodel of an LED structure to predict system and die level temperatures. The impact of LED array density, LED power density, and active versus passive cooling methods on device operation were calculated. In order to help understand the role of various thermal resistances in cooling such compact arrays, the thermal resistance network was analyzed in order to estimate the contributions from materials as well as active and passive cooling schemes. An analysis of thermal stresses and residual stresses in the die are also calculated based on power dissipation and convection heat transfer coefficients. Results show that the thermal stress in the GaN layer are compressive which can impact the band gap and performance of the LEDs.

  12. High power and single mode quantum cascade lasers.

    Science.gov (United States)

    Bismuto, Alfredo; Bidaux, Yves; Blaser, Stéphane; Terazzi, Romain; Gresch, Tobias; Rochat, Michel; Muller, Antoine; Bonzon, Christopher; Faist, Jerome

    2016-05-16

    We present a single mode quantum cascade laser with nearly 1 W optical power. A buried distributed feedback reflector is used on the back section for wavelength selection. The laser is 6 mm long, 3.5 μm wide, mounted episide-up and the laser facets are left uncoated. Laser emission is centered at 4.68 μm. Single-mode operation with a side mode suppression ratio of more than 30 dB is obtained in whole range of operation. Farfield measurements prove a symmetric, single transverse-mode emission in TM00-mode with typical divergences of 41° and 33° in the vertical and horizontal direction respectively. This work shows the potential for simple fabrication of high power lasers compatible with standard DFB processing.

  13. Prospects for high-power radioactive beam facilities worldwide

    CERN Document Server

    Nolen, Jerry A

    2003-01-01

    Advances in accelerators, targets, ion sources, and experimental instrumentation are making possible ever more powerful facilities for basic and applied research with short-lived radioactive isotopes. There are several current generation facilities, based on a variety of technologies, operating worldwide. These include, for example, those based on the in-flight method such as the recently upgraded National Superconducting Cyclotron Laboratory at Michigan State University, the facility at RIKEN in Japan, GANIL in Caen, France, and GSI in Darmstadt, Germany. Present facilities based on the Isotope-Separator On-Line method include, for example, the ISOLDE laboratory at CERN, HRIBF at Oak Ridge, and the new high-power facility ISAC at TRIUMF in Vancouver. Next-generation facilities include the Radioactive-Ion Factory upgrade of RIKEN to higher energy and intensity and the upgrade of ISAC to a higher energy secondary beam; both of these projects are in progress. A new project, LINAG, to upgrade the capabilities at...

  14. High power optical transmitter package for free space optical communication

    Science.gov (United States)

    Hildebrand, U.; Menke, B.; Wiesmann, Th.; Ohm, G.

    1990-07-01

    This paper discusses the characteristics of a new concept involving high-power laser diode (HPLD) arrays which are able to emit up to 1000 mW of optical output power but which suffer from poor far-field pattern and poor optical quality, related to the gain guiding mechanism used in such devices. Methods are proposed for improving the optical quality of HPLDs. These include the use of apertured AM scheme for HPLDs and the use of a graded-index lens and a stripe mirror to stabilize the HPLD. A HPLD optical transmitter is designed which will have the capability of operating the HPLD in the 180 deg phase alternating mode under modulation.

  15. High powered rocketry: design, construction, and launching experience and analysis

    Science.gov (United States)

    Paulson, Pryce; Curtis, Jarret; Bartel, Evan; Owens Cyr, Waycen; Lamsal, Chiranjivi

    2018-01-01

    In this study, the nuts and bolts of designing and building a high powered rocket have been presented. A computer simulation program called RockSim was used to design the rocket. Simulation results are consistent with time variations of altitude, velocity, and acceleration obtained in the actual flight. The actual drag coefficient was determined by using altitude back-tracking method and found to be 0.825. Speed of the exhaust determined to be 2.5 km s‑1 by analyzing the thrust curve of the rocket. Acceleration in the coasting phase of the flight, represented by the second-degree polynomial of a small leading coefficient, have been found to approach ‘-g’ asymptotically.

  16. The interaction of high-power lasers with plasmas

    CERN Document Server

    Eliezer, Shalom

    2002-01-01

    The Interaction of High-Power Lasers with Plasmas provides a thorough self-contained discussion of the physical processes occurring in laser-plasma interactions, including a detailed review of the relevant plasma and laser physics. The book analyzes laser absorption and propagation, electron transport, and the relevant plasma waves in detail. It also discusses the physics of the electric and magnetic fields in a laser-induced plasma medium, laser-induced shock waves, rarefaction waves, heat waves, and the related hydrodynamic instabilities (Rayleigh-Taylor, Richtmyer-Meshkov, and Kelvin-Helmholtz).A pedagogical presentation, the book addresses the basic physics issues from first principles, using simple models wherever appropriate. The coverage provides a foundation on which the graduate student can build an understanding of the past and present research in this field. For the experienced researcher, the book is a comprehensive and useful presentation of laser-plasma interactions.

  17. Effect of high power low frequency ultrasound processing on the stability of lycopene.

    Science.gov (United States)

    Oliveira, Valéria S; Rodrigues, Sueli; Fernandes, Fabiano A N

    2015-11-01

    The stability of lycopene was evaluated after application of high power low frequency ultrasound. The study was carried out on a solution containing pure lycopene to evaluate the direct effect of ultrasound on lycopene and on tomato purée to evaluate the direct and indirect effects of ultrasound application within a food matrix. Power densities ranging from 55 to 5000 W/L and temperatures ranging from 23°C (ambient) to 60°C were evaluated. The experiments on pure lycopene showed that the application of ultrasound did not have any direct effect over lycopene. However, the retention of lycopene in tomato puree has decreased indicating an indirect effect on lycopene stability caused by high concentration of hydrogen peroxide and the activation of peroxidase enzymes leading to the reduction of ascorbic acid and its regenerative action towards lycopene. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. High power diode laser Master Oscillator-Power Amplifier (MOPA)

    Science.gov (United States)

    Andrews, John R.; Mouroulis, P.; Wicks, G.

    1994-01-01

    High power multiple quantum well AlGaAs diode laser master oscillator - power amplifier (MOPA) systems were examined both experimentally and theoretically. For two pass operation, it was found that powers in excess of 0.3 W per 100 micrometers of facet length were achievable while maintaining diffraction-limited beam quality. Internal electrical-to-optical conversion efficiencies as high as 25 percent were observed at an internal amplifier gain of 9 dB. Theoretical modeling of multiple quantum well amplifiers was done using appropriate rate equations and a heuristic model of the carrier density dependent gain. The model gave a qualitative agreement with the experimental results. In addition, the model allowed exploration of a wider design space for the amplifiers. The model predicted that internal electrical-to-optical conversion efficiencies in excess of 50 percent should be achievable with careful system design. The model predicted that no global optimum design exists, but gain, efficiency, and optical confinement (coupling efficiency) can be mutually adjusted to meet a specific system requirement. A three quantum well, low optical confinement amplifier was fabricated using molecular beam epitaxial growth. Coherent beam combining of two high power amplifiers injected from a common master oscillator was also examined. Coherent beam combining with an efficiency of 93 percent resulted in a single beam having diffraction-limited characteristics. This beam combining efficiency is a world record result for such a system. Interferometric observations of the output of the amplifier indicated that spatial mode matching was a significant factor in the less than perfect beam combining. Finally, the system issues of arrays of amplifiers in a coherent beam combining system were investigated. Based upon experimentally observed parameters coherent beam combining could result in a megawatt-scale coherent beam with a 10 percent electrical-to-optical conversion efficiency.

  19. Coherent beam combining architectures for high power tapered laser arrays

    Science.gov (United States)

    Schimmel, G.; Janicot, S.; Hanna, M.; Decker, J.; Crump, P.; Erbert, G.; Witte, U.; Traub, M.; Georges, P.; Lucas-Leclin, G.

    2017-02-01

    Coherent beam combining (CBC) aims at increasing the spatial brightness of lasers. It consists in maintaining a constant phase relationship between different emitters, in order to combine them constructively in one single beam. We have investigated the CBC of an array of five individually-addressable high-power tapered laser diodes at λ = 976 nm, in two architectures: the first one utilizes the self-organization of the lasers in an interferometric extended-cavity, which ensures their mutual coherence; the second one relies on the injection of the emitters by a single-frequency laser diode. In both cases, the coherent combining of the phase-locked beams is ensured on the front side of the array by a transmission diffractive grating with 98% efficiency. The passive phase-locking of the laser bar is obtained up to 5 A (per emitter). An optimization algorithm is implemented to find the proper currents in the five ridge sections that ensured the maximum combined power on the front side. Under these conditions we achieve a maximum combined power of 7.5 W. In the active MOPA configuration, we can increase the currents in the tapered sections up to 6 A and get a combined power of 11.5 W, corresponding to a combining efficiency of 76%. It is limited by the beam quality of the tapered emitters and by fast phase fluctuations between emitters. Still, these results confirm the potential of CBC approaches with tapered lasers to provide a high-power and high-brightness beam, and compare with the current state-of-the-art with laser diodes.

  20. Multiple pulse electron beam converter design for high power radiography

    Science.gov (United States)

    Pincosy, P. A.; Back, N.; Bergstrom, P. M.; Chen, Yu-Jiuan; Poulsen, P.

    2001-06-01

    The typical response of the x-ray converter material to the passage of a high-powered relativistic electron beam is vaporization and rapid dispersal. The effect of this dispersal on subsequent pulses for multi-pulse radiography is the collective effects on the propagation of the electron beam through the expanding plasma and the reduced number of electron to photon interactions. Thus, for the dual-axis radiographic hydrodynamic test facility, the converter material must either be replaced or confined long enough to accommodate the entire pulse train. Typically the 1-mm-thick high Z and full density converter material is chosen to give peak dose and minimum radiographic spot. For repeated pulses we propose a modified converter, constructed of either low density, high Z material in the form of foam or of foils spaced over ten times the axial thickness of the standard 1 mm converter. The converter material is confined within a tube to impede outward motion in radius outside the beam interaction region. We report single-pulse experiments which measure the dose and spot size produced by the modified converter and compare them to similar measurements made by the standard converter. For multiple pulses over a microsecond time scale, we calculate the radial and axial hydrodynamic flow to study the material reflux into the converter volume and the resultant density decrease as the electron beam energy is deposited. Both the electron transport through the expanding low density plasma and beam in the higher density material are modeled. The x-ray source dose and spot size are calculated to evaluate the impact of the changing converter material density distribution on the radiographic spot size and dose. The results indicate that a multiple-pulse converter design for three or four high-power beam pulses is feasible.

  1. Comparative study of nonideal beam effects in high gain harmonic generation and self-seeded free electron lasers

    Directory of Open Access Journals (Sweden)

    Agostino Marinelli

    2010-07-01

    Full Text Available In this paper we investigate and compare the properties of two narrow-bandwidth free-electron laser (FEL schemes, one using self-seeding and the other high gain harmonic generation (HGHG. The two systems have been thoroughly studied analytically and numerically in the past. The aim of this work is to compare their performances when the FEL is driven by an electron beam with nonideal properties, thus including effects such as shot-to-shot energy fluctuations and nonlinear energy chirp. In both cases nonlinearities produce a bandwidth larger than the Fourier transform limited value. However, our analysis indicates that, for approximately the same output power levels, the self-seeding scheme is less affected than the HGHG scheme by quadratic energy chirps in the electron beam longitudinal phase space. This is confirmed by a specific numerical example corresponding to SPARX parameters where the electron beam was optimized to minimize the FEL gain length. The work has been carried out with the aid of the time dependent FEL codes GENESIS 1.3 (3D and PERSEO (1D.

  2. Implementation of high-gain observer on low-cost fused IR-OS sensor embedded in UAV system

    Science.gov (United States)

    Nor, E. Mohd; Noor, S. B. Mohd; Bahiki, M. R.; Azrad, S.

    2017-12-01

    This paper presents discrete time implementation of a high gain observer (HGO) and extended term to estimate the state velocity and acceleration from the position measured by a low-cost sensor installed on-board the unmanned aerial vehicle (UAV). Owing to the low-cost sensor, the signal produced from fused IR–OS is noisy and therefore, additional filters are used to remove the noise. This study proposes an alternative to this standard and tedious procedure using HGO. The discrete time implementation of HGO and its extended term is presented and ground tests are conducted to verify the algorithm by inducing a dynamic motion on the UAV platform embedded with the fusion IR-OS onboard. A comparison study is conducted using standard numerical differentiation and ground truth measurement by OptiTrack. The results show that EHGO can produce a velocity signal with the same quality as that of differentiated signal from fused IR-OS using Kalman filter. The novelty of HGO lies in its simplicity and its minimal tuning of parameters.

  3. Radial current high power dummy load for characterizing the high power laser triggered transformer-type accelerator.

    Science.gov (United States)

    Yin, Yi; Zhong, Hui-Huang; Liu, Jin-Liang; Ren, He-Ming; Yang, Jian-Hua; Zhang, Xiao-Ping; Hong, Zhi-qiang

    2010-09-01

    A radial-current aqueous resistive solution load was applied to characterize a laser triggered transformer-type accelerator. The current direction in the dummy load is radial and is different from the traditional load in the axial. Therefore, this type of dummy load has smaller inductance and fast response characteristic. The load was designed to accommodate both the resistance requirement of accelerator and to allow optical access for the laser. Theoretical and numerical calculations of the load's inductance and capacitance are given. The equivalent circuit of the dummy load is calculated in theory and analyzed with a PSPICE code. The simulation results agree well with the theoretical analysis. At last, experiments of the dummy load applied to the high power spiral pulse forming line were performed; a quasisquare pulse voltage is obtained at the dummy load.

  4. Hall Effect Thruster for High Power Solar Electric Propulsion Technology Demonstration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek proposes to develop a flight version of a high power Hall Effect thruster. While numerous high power Hall Effect thrusters have been demonstrated in the...

  5. High-power LED illumination system for photosynthetic research on potted plant canopies

    Science.gov (United States)

    Thestrup, Birgitte; Dam-Hansen, Carsten; Lund, Janni B.; Rosenqvist, Eva

    2008-02-01

    The high energy efficiency and radiant flux of high-power LED devices has lead to many new applications of LED lighting. Within the more production oriented applied plant research, there is a need for illumination systems that ensures a high irradiance, spectral control and homogeneous illumination of a large plant canopy to ensure reproducible results over long term measurements. A new high power LED illumination system is presented. It has been designed and developed for illumination of a plant canopy area of 60 x 80 cm2 in a climate chamber where photosynthesis of the whole canopy can be measured. The LED system extends the precise control of the chamber climate with computer control and long term stability of the irradiance and spectral composition of the illumination. High-power red and blue (at 455 and 639 nm) LED devices have been chosen that coincides with the absorption peaks of chlorophyll. The illumination system allows for a maximum irradiance of 6.3 W/cm2 corresponding to a photosynthetic photon flux density (PPFD) of 300 μmol m -2 s -1. The spectral composition of the light given by the ratio of blue photons compared to the total number of red and blue photons can be adjusted from 0-40 % keeping the irradiance at a constant level. Spectroradiometric 2D grid measurement at the plant top level shows homogeneity of +/- 5% of the irradiance and +/- 5% of the spectral distribution, over almost the entire canopy area. Initial experiments carried out on Chrysanthemum plants showing the dependence of the photosynthesis on blue light fraction is presented and discussed.

  6. Design of a high-power load for millimetre-wave Gaussian beams

    Science.gov (United States)

    Bruschi, A.; Cirant, S.; Gandini, F.; Granucci, G.; Mellera, V.; Muzzini, V.; Nardone, A.; Simonetto, A.; Sozzi, C.; Spinicchia, N.

    2003-11-01

    The design of a compact matched load for high-power measurements and testing of gyrotrons and transmission lines in ECRH plants for fusion research applications is currently in an advanced phase. The aim is to provide more than 95% absorption and precise calorimetric measurement of the input power in CW. This work is based on the results of tests at high power and short pulse length (140 GHz, 0.5 MW, 0.5 s) on loads installed on the ECRH plant of the FTU Tokamak in Frascati. The loads consist basically of hollow spheres of copper with the inner wall covered by plasma-sprayed lossy ceramics. Tests at higher power and longer pulses on the ASDEX-Upgrade ECRH plant showed, after a number of successful pulses, progressive damage on the absorbing layer, marked by the appearance of electrical arcs. The absorber degradation, showing specific damage patterns, due to exposure to high-power millimetre waves, has been analysed in detail and strategies are proposed, in order to improve the power-handling capabilities and the energy extraction rate. New measurements of millimetric absorption and thermal conductivity have been performed on samples of different ceramics, for choosing the best absorbing layer. A modified expander mirror surface with a better deposition profile, numerically computed with a multi-reflection model of the sphere, is designed to avoid radiation accumulation close to the entrance port. Improved cooling channels, which in principle can exploit the increased heat transfer rate due to surface boiling, as used in high-performance cooling circuits such as plasma-facing components, will provide 1-MW CW power capability. In this paper, some technical solutions for the construction and the constraints on the allowable deformation during pulses are given.

  7. The use of a high-power laser on swine mitral valve chordae tendineae.

    Science.gov (United States)

    Pinto, Nathali Cordeiro; Chavantes, M Cristina; Zezell, Denise; Deana, Alessandro; Benetti, Carolina; Marcos, Rodrigo Labat; Lopes, Luciana Almeida; Martins, Rodrigo A B Lopes; Aiello, Vera Demarchi; Jatene, Fabio Biscegli; Pomerantzeff, Pablo M A

    2016-08-01

    Worldwide, rheumatic fever remains a significant cause of mitral valve insufficiency. It is responsible for approximately 90 % of early childhood valvular surgeries in Brazil. Elongated or flail chordae are frequently responsible and require surgical correction. The purpose of this study was to analyze and compare the histological tissues of the mitral valve chordae and the mechanical resistance generated by the chordae, both with and without the application of a high-power laser. Twenty normal porcine mitral valve chordae were measured and divided randomly into the following two groups: control group (not subjected to a high-power laser) and laser group (subjected to photonic irradiation). Laser surgery was performed under controlled conditions, using following parameters: λ = 980-nm wavelength, power = 3 W, and energy = 60 J. A mechanical test machine was used in combination with a subsequent histological study to measure chordae tensile properties. A histological analysis demonstrated a typical collagen bundle arrangement in the control group; however, under a particular reached temperature range (48), the collagen bundles assumed different arrangements in the laser group. Significant reductions in the chordae tendineae lengths and changes in their resistance in the laser group were observed, as these chordae exhibited less rigid fibers. The chordae tendineae of normal porcine valves subjected to a high-power laser exhibited its length reduction and less stiffness compared to the control group. A histological analysis of the laser treatment specimens demonstrated differences in collagen bundle spatial organization, following slight changes into tissue temperature.

  8. DOE HIGH-POWER SLIM-HOLE DRILLING SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Dr. William C. Maurer; John H. Cohen; J. Chris Hetmaniak; Curtis Leitko

    1999-09-01

    This project used a systems approach to improve slim-hole drilling performance. A high power mud motor, having a double-length power section, and hybrid PDC/TSP drill bit were developed to deliver maximum horsepower to the rock while providing a long life down hole. This high-power slim-hole drilling system drills much faster than conventional slim-hole motor and bit combinations and holds significant potential to reduce slim-hole drilling costs. The oil and gas industries have been faced with downward price pressures since the 1980s. These pressures are not expected to be relieved in the near future. To maintain profitability, companies have had to find ways to reduce the costs of producing oil and gas. Drilling is one of the more costly operations in the production process. One method to reduce costs of drilling is to use smaller more mobile equipment. Slim holes have been drilled in the past using this principle. These wells can save money not only from the use of smaller drilling equipment, but also from reduced tubular costs. Stepping down even one casing size results in significant savings. However, slim holes have not found wide spread use for three reasons. First, until recently, the price of oil has been high so there were no forces to move the industry in this direction. Second, small roller bits and motors were not very reliable and they drilled slowly, removing much of the economic benefit. The third and final reason was the misconception that large holes were needed everywhere to deliver the desired production. Several factors have changed that will encourage the use of slim holes. The industry now favors any method of reducing the costs of producing oil and gas. In addition, the industry now understands that large holes are not always needed. Gas, in particular, can have high production rates in smaller holes. New materials now make it possible to manufacture improved bits and motors that drill for long periods at high rates. All that remains is to

  9. Control system for high power laser drilling workover and completion unit

    Science.gov (United States)

    Zediker, Mark S; Makki, Siamak; Faircloth, Brian O; DeWitt, Ronald A; Allen, Erik C; Underwood, Lance D

    2015-05-12

    A control and monitoring system controls and monitors a high power laser system for performing high power laser operations. The control and monitoring system is configured to perform high power laser operation on, and in, remote and difficult to access locations.

  10. High-Power Solid-State Lasers from a Laser Glass Perspective

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J H; Hayden, J S; Marker, A J

    2010-12-17

    Advances in laser glass compositions and manufacturing have enabled a new class of high-energy/high-power (HEHP), petawatt (PW) and high-average-power (HAP) laser systems that are being used for fusion energy ignition demonstration, fundamental physics research and materials processing, respectively. The requirements for these three laser systems are different necessitating different glasses or groups of glasses. The manufacturing technology is now mature for melting, annealing, fabricating and finishing of laser glasses for all three applications. The laser glass properties of major importance for HEHP, PW and HAP applications are briefly reviewed and the compositions and properties of the most widely used commercial laser glasses summarized. Proposed advances in these three laser systems will require new glasses and new melting methods which are briefly discussed. The challenges presented by these laser systems will likely dominate the field of laser glass development over the next several decades.

  11. High power ultrasonics as a novel tool offering new opportunities for managing wine microbiology.

    Science.gov (United States)

    Jiranek, Vladimir; Grbin, Paul; Yap, Andrew; Barnes, Mark; Bates, Darren

    2008-01-01

    Industrial scale food and beverage processes that utilize microorganisms are typically faced with issues related to the exclusion, suppression or elimination of spoilage organisms. Yet the use of traditional anti-microbial treatments such as heat, chemical biocides or sterile filtration may themselves be restricted by regulations or else be undesirable due to their adverse sensory impacts on the product. High power ultrasound (HPU) is a technology whose application has been evaluated if not exploited in several food and beverage processes but has yet to be introduced into the wine industry. This review examines the research findings from related industries and highlights possible applications and likely benefits of the use of HPU in winemaking.

  12. Data Processing Middleware in a High-Powered Neutral Beam Injection Control System

    Science.gov (United States)

    Sheng, Peng; Hu, Chundong; Song, Shihua; Liu, Zhimin; Zhao, Yuanzhe; Zhang, Xiaodan; Dou, Shaobin

    2013-06-01

    A set of data-processing middleware for a high-powered neutral beam injection (NBI) control system is presented in this paper. The middleware, based on TCP/IP and multi-threading technologies, focuses mainly on data processing and transmission. It separates the data processing and compression from data acquisition and storage. It provides universal transmitting interfaces for different software circumstances, such as WinCC, LabView and other measurement systems. The experimental data acquired on Windows, QNX and Linux platforms are processed by the middleware and sent to the monitoring applications. There are three middleware deployment models: serial processing, parallel processing and alternate serial processing. By using these models, the middleware solves real-time data-processing problems on heterogeneous environmental acquisition hardware with different operating systems and data applications.

  13. Load Torque Compensator for Model Predictive Direct Current Control in High Power PMSM Drive Systems

    DEFF Research Database (Denmark)

    Preindl, Matthias; Schaltz, Erik

    2010-01-01

    the use of a current controller which takes into account the discrete states of the inverter, e.g. DTC or a more modern approach: Model Predictive Direct Current Control (MPDCC). Moreover overshoots and oscillations in the speed are not desired in many applications, since they lead to mechanical stress......In drive systems the most used control structure is the cascade control with an inner torque, i.e. current and an outer speed control loop. The fairly small converter switching frequency in high power applications, e.g. wind turbines lead to modest speed control performance. An improvement bring...... behaviour. It compensates the load torque influence on the speed control setting a feed forward torque value, i.e. current reference value. The benefits are twice. The speed controller reaches immediately the speed reference value avoiding offsets which must be compensated by the weak integrator. Moreover...

  14. Radiological Environmental Protection for LCLS-II High Power Operation

    Science.gov (United States)

    Liu, James; Blaha, Jan; Cimeno, Maranda; Mao, Stan; Nicolas, Ludovic; Rokni, Sayed; Santana, Mario; Tran, Henry

    2017-09-01

    The LCLS-II superconducting electron accelerator at SLAC plans to operate at up to 4 GeV and 240 kW average power, which would create higher radiological impacts particularly near the beam loss points such as beam dumps and halo collimators. The main hazards to the public and environment include direct or skyshine radiation, effluent of radioactive air such as 13N, 15O and 41Ar, and activation of groundwater creating tritium. These hazards were evaluated using analytic methods and FLUKA Monte Carlo code. The controls (mainly extensive bulk shielding and local shielding around high loss points) and monitoring (neutron/photon detectors with detection capabilities below natural background at site boundary, site-wide radioactive air monitors, and groundwater wells) were designed to meet the U.S. DOE and EPA, as well as SLAC requirements. The radiological design and controls for the LCW systems [including concrete housing shielding for 15O and 11C circulating in LCW, 7Be and erosion/corrosion products (22Na, 54Mn, 60Co, 65Zn, etc.) captured in resin and filters, leak detection and containment of LCW with 3H and its waste water discharge; explosion from H2 build-up in surge tank and release of radionuclides] associated with the high power beam dumps are also presented.

  15. Plasma characteristics of a high power helicon discharge

    Energy Technology Data Exchange (ETDEWEB)

    Ziemba, T; Euripides, P; Slough, J; Winglee, R; Giersch, L; Carscadden, J; Schnackenberg, T; Isley, S [Box 351310, University of Washington, Seattle WA, 98195 (United States)

    2006-08-01

    A new high power helicon (HPH) plasma system has been designed to provide input powers of several tens of kilowatts to produce a large area (0.5 m{sup 2}) of uniform high-density, of at least 5 x 10{sup 17} m{sup -3}, plasma downstream from the helicon coil. Axial and radial plasma characteristics show that the plasma is to a lesser extent created in and near the helicon coil and then is accelerated into the axial and equatorial regions. The bulk acceleration of the plasma is believed to be due to a coupling of the bulk of the electrons to the helicon field, which in turn transfers energy to the ions via ambipolar diffusion. The plasma beta is near unity a few centimetres away from the HPH system and Bdot measurements show {delta}B perturbations in the order of the vacuum magnetic field magnitude. In the equatorial region, a magnetic separatrix is seen to develop roughly at the mid-point between the helicon and chamber wall. The magnetic perturbation develops on the time scale of the plasma flow speed and upon the plasma reaching the chamber wall decays to the vacuum magnetic field configuration within 200 {mu}s.

  16. Advanced, High Power, Next Scale, Wave Energy Conversion Device

    Energy Technology Data Exchange (ETDEWEB)

    Mekhiche, Mike [Principal Investigator; Dufera, Hiz [Project Manager; Montagna, Deb [Business Point of Contact

    2012-10-29

    The project conducted under DOE contract DE‐EE0002649 is defined as the Advanced, High Power, Next Scale, Wave Energy Converter. The overall project is split into a seven‐stage, gated development program. The work conducted under the DOE contract is OPT Stage Gate III work and a portion of Stage Gate IV work of the seven stage product development process. The project effort includes Full Concept Design & Prototype Assembly Testing building on our existing PowerBuoy technology to deliver a device with much increased power delivery. Scaling‐up from 150kW to 500kW power generating capacity required changes in the PowerBuoy design that addressed cost reduction and mass manufacturing by implementing a Design for Manufacturing (DFM) approach. The design changes also focused on reducing PowerBuoy Installation, Operation and Maintenance (IO&M) costs which are essential to reducing the overall cost of energy. In this design, changes to the core PowerBuoy technology were implemented to increase capability and reduce both CAPEX and OPEX costs. OPT conceptually envisaged moving from a floating structure to a seabed structure. The design change from a floating structure to seabed structure would provide the implementation of stroke‐ unlimited Power Take‐Off (PTO) which has a potential to provide significant power delivery improvement and transform the wave energy industry if proven feasible.

  17. High power, higher order ultrafast hollow Gaussian beams

    Science.gov (United States)

    Apurv Chaitanya, N.; Amrit Chaitanya, Banerji, J.; Samanta, G. K.

    2017-05-01

    We report on linear and nonlinear generation of ultrafast hollow Gaussian beams (HGBs). Using only two spiral phase plates (SPPs) having phase variation corresponding to vortex orders, l = 1 and 2, and an experimental scheme, we have generated high power, ultrafast HGBs of orders up to 3 at 1064 nm. Based on single-pass, frequency doubling of the HGBs in a 5 mm long, MgO doped, periodically poled LiNbO3 (MgO:PPLN) crystal, we have produced HGBs of average output power in excess of 250 mW at 532 nm and order as high as 6. Experimentally, we verified that the frequency doubled HGBs have orders twice those of the pump HGBs. Like the Gaussian beams, the HGBs of all orders have an optimum focusing condition for the highest conversion efficiency. On the contrary to previous reports, we observed that the propagation of the vortex beam of order, l, through a SPP corresponding to the vortex order of, -l, results in HGBs of the same order, | l | .

  18. The Challenges of High-Power Plasma Propulsion

    Science.gov (United States)

    Chang-Diaz, Franklin

    2004-11-01

    Our future space explorers face many challenges but three loom high above the rest: physiological debilitation, radiation and psychological stress. Counter-measures are presently being considered to ameliorate these difficulties; however, two new developments are required: abundant space power and advanced propulsion. Also, electric propulsion, long relegated to low-power thrusters, has been reinvigorated by interest in multi-megawatt plasma propulsion. One rapidly evolving concept, the Variable Specific Impulse Magnetoplasma Rocket (VASIMR,) borrows heavily from magnetic fusion research, particularly on RF plasma generation and heating in mirror-like geometries. Axial momentum is obtained by expansion of the plasma in a magnetic nozzle. The configuration could enable thrust and specific impulse variation, at constant power, allowing in-flight mission performance optimization. VASIMR technology, and similar others, could be validated, in the near term, on the International Space Station, where they can benefit from a container-less environment and virtually infinite vacuum. The experiments could also help re-boost the orbital facility. This paper describes the advantages and operational motivation for high-power plasma rockets, illustrated through the VASIMR research effort.

  19. Discharge Physics of High Power Impulse Magnetron Sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre

    2010-10-13

    High power impulse magnetron sputtering (HIPIMS) is pulsed sputtering where the peak power exceeds the time-averaged power by typically two orders of magnitude. The peak power density, averaged over the target area, can reach or exceed 107 W/m2, leading to plasma conditions that make ionization of the sputtered atoms very likely. A brief review of HIPIMS operation is given in a tutorial manner, illustrated by some original data related to the self-sputtering of niobium in argon and krypton. Emphasis is put on the current-voltage-time relationships near the threshold of self-sputtering runaway. The great variety of current pulse shapes delivers clues on the very strong gas rarefaction, self-sputtering runaway conditions, and the stopping of runaway due to the evolution of atom ionization and ion return probabilities as the gas plasma is replaced by metal plasma. The discussions are completed by considering instabilities and the special case of ?gasless? self-sputtering.

  20. High Power RF Test Facility at the SNS

    CERN Document Server

    Kang, Yoon W; Campisi, Isidoro E; Champion, Mark; Crofford, Mark; Davis, Kirk; Drury, Michael A; Fuja, Ray E; Gurd, Pamela; Kasemir, Kay-Uwe; McCarthy, Michael P; Powers, Tom; Shajedul Hasan, S M; Stirbet, Mircea; Stout, Daniel; Tang, Johnny Y; Vassioutchenko, Alexandre V; Wezensky, Mark

    2005-01-01

    RF Test Facility has been completed in the SNS project at ORNL to support test and conditioning operation of RF subsystems and components. The system consists of two transmitters for two klystrons powered by a common high voltage pulsed converter modulator that can provide power to two independent RF systems. The waveguides are configured with WR2100 and WR1150 sizes for presently used frequencies: 402.5 MHz and 805 MHz. Both 402.5 MHz and 805 MHz systems have circulator protected klystrons that can be powered by the modulator capable of delivering 11 MW peak and 1 MW average power. The facility has been equipped with computer control for various RF processing and complete dual frequency operation. More than forty 805 MHz fundamental power couplers for the SNS superconducting linac (SCL) cavitites have been RF conditioned in this facility. The facility provides more than 1000 ft2 floor area for various test setups. The facility also has a shielded cave area that can support high power tests of normal conducti...

  1. Fiber facet gratings for high power fiber lasers

    Science.gov (United States)

    Vanek, Martin; Vanis, Jan; Baravets, Yauhen; Todorov, Filip; Ctyroky, Jiri; Honzatko, Pavel

    2017-12-01

    We numerically investigated the properties of diffraction gratings designated for fabrication on the facet of an optical fiber. The gratings are intended to be used in high-power fiber lasers as mirrors either with a low or high reflectivity. The modal reflectance of low reflectivity polarizing grating has a value close to 3% for TE mode while it is significantly suppressed for TM mode. Such a grating can be fabricated on laser output fiber facet. The polarizing grating with high modal reflectance is designed as a leaky-mode resonant diffraction grating. The grating can be etched in a thin layer of high index dielectric which is sputtered on fiber facet. We used refractive index of Ta2O5 for such a layer. We found that modal reflectance can be close to 0.95 for TE polarization and polarization extinction ratio achieves 18 dB. Rigorous coupled wave analysis was used for fast optimization of grating parameters while aperiodic rigorous coupled wave analysis, Fourier modal method and finite difference time domain method were compared and used to compute modal reflectance of designed gratings.

  2. High power continuous-wave titanium:sapphire laser

    Science.gov (United States)

    Erbert, Gaylen V.; Bass, Isaac L.; Hackel, Richard P.; Jenkins, Sherman L.; Kanz, Vernon K.; Paisner, Jeffrey A.

    1993-01-01

    A high-power continuous-wave laser resonator (10) is provided, wherein first, second, third, fourth, fifth and sixth mirrors (11-16) form a double-Z optical cavity. A first Ti:Sapphire rod (17) is disposed between the second and third mirrors (12,13) and at the mid-point of the length of the optical cavity, and a second Ti:Sapphire rod (18) is disposed between the fourth and fifth mirrors (14,15) at a quarter-length point in the optical cavity. Each Ti:Sapphire rod (17,18) is pumped by two counter-propagating pump beams from a pair of argon-ion lasers (21-22, 23-24). For narrow band operation, a 3-plate birefringent filter (36) and an etalon (37) are disposed in the optical cavity so that the spectral output of the laser consists of 5 adjacent cavity modes. For increased power, seventy and eighth mirrors (101, 192) are disposed between the first and second mirrors (11, 12) to form a triple-Z optical cavity. A third Ti:Sapphire rod (103) is disposed between the seventh and eighth mirrors (101, 102) at the other quarter-length point in the optical cavity, and is pumped by two counter-propagating pump beams from a third pair of argon-ion lasers (104, 105).

  3. Radiological Environmental Protection for LCLS-II High Power Operation

    Directory of Open Access Journals (Sweden)

    Liu James

    2017-01-01

    Full Text Available The LCLS-II superconducting electron accelerator at SLAC plans to operate at up to 4 GeV and 240 kW average power, which would create higher radiological impacts particularly near the beam loss points such as beam dumps and halo collimators. The main hazards to the public and environment include direct or skyshine radiation, effluent of radioactive air such as 13N, 15O and 41Ar, and activation of groundwater creating tritium. These hazards were evaluated using analytic methods and FLUKA Monte Carlo code. The controls (mainly extensive bulk shielding and local shielding around high loss points and monitoring (neutron/photon detectors with detection capabilities below natural background at site boundary, site-wide radioactive air monitors, and groundwater wells were designed to meet the U.S. DOE and EPA, as well as SLAC requirements. The radiological design and controls for the LCW systems [including concrete housing shielding for 15O and 11C circulating in LCW, 7Be and erosion/corrosion products (22Na, 54Mn, 60Co, 65Zn, etc. captured in resin and filters, leak detection and containment of LCW with 3H and its waste water discharge; explosion from H2 build-up in surge tank and release of radionuclides] associated with the high power beam dumps are also presented.

  4. Overview of High Power Vacuum Dry RF Load Designs

    Energy Technology Data Exchange (ETDEWEB)

    Krasnykh, Anatoly [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    A specific feature of RF linacs based on the pulsed traveling wave (TW) mode of operation is that only a portion of the RF energy is used for the beam acceleration. The residual RF energy has to be terminated into an RF load. Higher accelerating gradients require higher RF sources and RF loads, which can stably terminate the residual RF power. RF feeders (from the RF source though the accelerating section to the load) are vacuumed to transmit multi-megawatt high power RF. This overview will outline vacuumed RF loads only. A common method to terminate multi-MW RF power is to use circulated water (or other liquid) as an absorbing medium. A solid dielectric interface (a high quality ceramic) is required to separate vacuum and liquid RF absorber mediums. Using such RF load approaches in TW linacs is troubling because there is a fragile ceramic window barrier and a failure could become catastrophic for linac vacuum and RF systems. Traditional loads comprising of a ceramic disk have limited peak and average power handling capability and are therefore not suitable for high gradient TW linacs. This overview will focus on ''vacuum dry'' or ''all-metal'' loads that do not employ any dielectric interface between vacuum and absorber. The first prototype is an original design of RF loads for the Stanford Two-Mile Accelerator.

  5. Radiation safety with high power operation of EURISOL

    CERN Document Server

    Ridikas, D

    2007-01-01

    The European Community has launched the design study for a next generation RIB facility able to increase by a few orders of magnitude, the exotic beam intensity and availability in Europe. Forty institutes and laboratories within Europe, North America and Asia are taking part in this consortium, named EURISOL DS project (European Isotope Separation On Line Design Study). In EURISOL, four target stations are foreseen, three direct targets of approximately 100 kW of beam power and one multi-MW (MMW) target assembly, all driven by a high-power particle accelerator. In this MMW station, high-intensity RIBs of neutron-rich isotopes will be obtained by inducing fission in several actinide targets surrounding a liquid metal spallation neutron source. The envisaged increase in RIB intensities at EURISOL means a drastic increase of the radioactive inventory and corresponding radioprotection related issues. Safety aspects of the future RIB production targets (aiming at a few ~1015 fissions/s) will become decisive in li...

  6. LCLS-II high power RF system overview and progress

    Energy Technology Data Exchange (ETDEWEB)

    Yeremian, Anahid Dian

    2015-10-07

    A second X-ray free electron laser facility, LCLS-II, will be constructed at SLAC. LCLS-II is based on a 1.3 GHz, 4 GeV, continuous-wave (CW) superconducting linear accelerator, to be installed in the first kilometer of the SLAC tunnel. Multiple types of high power RF (HPRF) sources will be used to power different systems on LCLS-II. The main 1.3 GHz linac will be powered by 280 1.3 GHz, 3.8 kW solid state amplifier (SSA) sources. The normal conducting buncher in the injector will use four more SSAs identical to the linac SSAs but run at 2 kW. Two 185.7 MHz, 60 kW sources will power the photocathode dual-feed RF gun. A third harmonic linac section, included for linearizing the bunch energy spread before the first bunch compressor, will require sixteen 3.9 GHz sources at about 1 kW CW. A description and an update on all the HPRF sources of LCLS-II and their implementation is the subject of this paper.

  7. Thermal investigation on high power dfb broad area lasers at 975 nm, with 60% efficiency

    Science.gov (United States)

    Mostallino, R.; Garcia, M.; Deshayes, Y.; Larrue, A.; Robert, Y.; Vinet, E.; Bechou, L.; Lecomte, M.; Parillaud, O.; Krakowski, M.

    2016-03-01

    The demand of high power diode lasers in the range of 910-980nm is regularly growing. This kind of device for many applications, such as fiber laser pumping [1], material processing [1], solid-state laser pumping [1], defense and medical/dental. The key role of this device lies in the efficiency (𝜂𝐸) of converting input electrical power into output optical power. The high value of 𝜂𝐸 allows high power level and reduces the need in heat dissipation. The requirement of wavelength stabilization with temperature is more obvious in the case of multimode 975nm diode lasers used for pumping Yb, Er and Yb/Er co-doped solid-state lasers, due to the narrow absorption line close to this wavelength. Such spectral width property (stabilization (0.07 𝑛𝑚 • °𝐶-1), provided by a uniform distributed feedback grating (DFB) introduced by etching and re-growth process techniques, is achievable in high power diode lasers using optical feedback. This paper reports on the development of the diode laser structure and the process techniques required to write the gratings taking into account of the thermal dissipation and optical performances. Performances are particularly determined in terms of experimental electro-optical characterizations. One of the main objectives is to determine the thermal resistance of the complete assembly to ensure the mastering of the diode laser temperature for operating condition. The classical approach to determine junction temperature is based on the infrared thermal camera, the spectral measurement and the pulse electrical method. In our case, we base our measurement on the spectral measurement but this approach is not well adapted to the high power diodes laser studied. We develop a new measurement based on the pulse electrical method and using the T3STERequipment. This method is well known for electronic devices and LEDs but is weakly developed for the high power diodes laser. This crucial

  8. High-power and highly reliable 638-nm band BA-LD for CW operation

    Science.gov (United States)

    Nishida, Takehiro; Kuramoto, Kyosuke; Abe, Shinji; Kusunoki, Masatsugu; Miyashita, Motoharu; Yagi, Tetsuya

    2017-10-01

    High-power laser diodes (LDs) are strongly demanded as light sources of display applications. In multiple spatial light modulator-type projectors or liquid crystal displays, the light source LDs are operated under CW condition. The high-power 638-nm band broad-area LD for CW operation was newly developed. The LD consisted of two stripes with each width of 75 μm to reduce both an optical power density at a front facet and a threshold current. The newly improved epitaxial technology was also applied to the LD to suppress an electron overflow from an active layer. The LD showed superior output characteristics, such as output of 1.77 W at case temperature of 55 °C with wall plug efficiency (WPE) of 23%, which was improved by 40% compared with the current product. The peak WPE at 25 °C reached 40.6% under the output power of 2.37 W, CW, world highest.

  9. Ferroelectric switch for a high-power Ka-band active pulse compressor

    Energy Technology Data Exchange (ETDEWEB)

    Hirshfield, Jay L. [Omega-P, Inc., New Haven, CT (United States)

    2013-12-18

    Results are presented for design of a high-power microwave switch for operation at 34.3 GHz, intended for use in an active RF pulse compressor. The active element in the switch is a ring of ferroelectric material, whose dielectric constant can be rapidly changed by application of a high-voltage pulse. As envisioned, two of these switches would be built into a pair of delay lines, as in SLED-II at SLAC, so as to allow 30-MW μs-length Ka-band pulses to be compressed in time by a factor-of-9 and multiplied in amplitude to generate 200 MW peak power pulses. Such high-power pulses could be used for testing and evaluation of high-gradient mm-wave accelerator structures, for example. Evaluation of the switch design was carried out with an X-band (11.43 GHz) prototype, built to incorporate all the features required for the Ka-band version.

  10. High-power UV-LED degradation: Continuous and cycled working condition influence

    Science.gov (United States)

    Arques-Orobon, F. J.; Nuñez, N.; Vazquez, M.; Segura-Antunez, C.; González-Posadas, V.

    2015-09-01

    High-power (HP) UV-LEDs can replace UV lamps for real-time fluoro-sensing applications by allowing portable and autonomous systems. However, HP UV-LEDs are not a mature technology, and there are still open issues regarding their performance evolution over time. This paper presents a reliability study of 3 W UV-LEDs, with special focus on LED degradation for two working conditions: continuous and cycled (30 s ON and 30 s OFF). Accelerated life tests are developed to evaluate the influence of temperature and electrical working conditions in high-power LEDs degradation, being the predominant failure mechanism the degradation of the package. An analysis that includes dynamic thermal and optical HP UV-LED measurements has been performed. Static thermal and stress simulation analysis with the finite element method (FEM) identifies the causes of package degradation. Accelerated life test results prove that HP UV-LEDs working in cycled condition have a better performance than those working in continuous condition.

  11. The interaction of high-power lasers with plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Eliezer, S

    2003-02-12

    This book deals with the fundamental physics of numerous plasma processes that occur during laser plasma interactions. The subject matter is related to both basic plasma physics and applied physics. The author starts with the essentials of high power lasers whose duration ranges from nanoseconds to femtoseconds, and then builds up an introduction to plasma physics by describing ionization, well known transport coefficients (electrical and thermal conductivities, diffusion, viscosity, energy transport etc), Debye length, plasma oscillations and the properties of the laser induced plasma medium. The book contains plasma dynamical equations for describing the hydrodynamic and kinetic phenomena, and treating particle dynamics by computer simulation. The ponderomotive force is discussed for small amplitude electromagnetic fields in an unmagnetized plasma. However, for intense laser beams one should obtain new expressions for the relativistic ponderomotive force, which are totally absent from this book. Furthermore, in laser plasma interactions strong magnetic fields are produced which will drastically modify the relativistic ponderomotive force expressions. The physics of collisional absorption of electromagnetic waves and their propagation in a nonuniform unmagnetized plasma has been elegantly described. The phenomena of the resonance absorption of laser light is also discussed. Simple models for the parametric processes are developed, while there are no discussions of cavitons/envelope solitons. The latter are usually regarded as possible nonlinear states of the modulational/filamentational instabilities. Rather, the author presents a description of a K-dV equation for nonlinear ion-acoustic waves without the laser field. The description of a non-envelope ion-acoustic soliton has already appeared in many plasma physics textbooks. The book contains a short chapter on the self-similar plasma expansion in vacuum, double layers, and charged particle acceleration. However

  12. High Energy High Power Battery Exceeding PHEV40 Requirements

    Energy Technology Data Exchange (ETDEWEB)

    Rempel, Jane [TIAX LLC, Lexington, MA (United States)

    2016-03-31

    TIAX has developed long-life lithium-ion cells that can meet and exceed the energy and power targets (200Wh/kg and 800W/kg pulse power) set out by DOE for PHEV40 batteries. To achieve these targets, we selected and scaled-up a high capacity version of our proprietary high energy and high power CAM-7® cathode material. We paired the cathode with a blended anode containing Si-based anode material capable of delivering high capacity and long life. Furthermore, we optimized the anode blend composition, cathode and anode electrode design, and selected binder and electrolyte compositions to achieve not only the best performance, but also long life. By implementing CAM-7 with a Si-based blended anode, we built and tested prototype 18650 cells that delivered measured specific energy of 198Wh/kg total energy and 845W/kg at 10% SOC (projected to 220Wh/kg in state-of-the-art 18650 cell hardware and 250Wh/kg in 15Ah pouch cells). These program demonstration cells achieved 90% capacity retention after 500 cycles in on-going cycle life testing. Moreover, we also tested the baseline CAM-7/graphite system in 18650 cells showing that 70% capacity retention can be achieved after ~4000 cycles (20 months of on-going testing). Ultimately, by simultaneously meeting the PHEV40 power and energy targets and providing long life, we have developed a Li-ion battery system that is smaller, lighter, and less expensive than current state-of-the-art Li-ion batteries.

  13. Optimization Studies for ISOL Type High-Powered Targets

    Energy Technology Data Exchange (ETDEWEB)

    Remec, Igor [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ronningen, Reginald Martin [Michigan State Univ., East Lansing, MI (United States)

    2013-09-24

    The research studied one-step and two-step Isotope Separation on Line (ISOL) targets for future radioactive beam facilities with high driver-beam power through advanced computer simulations. As a target material uranium carbide in the form of foils was used because of increasing demand for actinide targets in rare-isotope beam facilities and because such material was under development in ISAC at TRIUMF when this project started. Simulations of effusion were performed for one-step and two step targets and the effects of target dimensions and foil matrix were studied. Diffusion simulations were limited by availability of diffusion parameters for UCx material at reduced density; however, the viability of the combined diffusion?effusion simulation methodology was demonstrated and could be used to extract physical parameters such as diffusion coefficients and effusion delay times from experimental isotope release curves. Dissipation of the heat from the isotope-producing targets is the limiting factor for high-power beam operation both for the direct and two-step targets. Detailed target models were used to simulate proton beam interactions with the targets to obtain the fission rates and power deposition distributions, which were then applied in the heat transfer calculations to study the performance of the targets. Results indicate that a direct target, with specification matching ISAC TRIUMF target, could operate in 500-MeV proton beam at beam powers up to ~40 kW, producing ~8 1013 fission/s with maximum temperature in UCx below 2200 C. Targets with larger radius allow higher beam powers and fission rates. For the target radius in the range 9-mm to 30-mm the achievable fission rate increases almost linearly with target radius, however, the effusion delay time also increases linearly with target radius.

  14. Thermal design and analysis of high power star sensors

    Directory of Open Access Journals (Sweden)

    Fan Jiang

    2015-09-01

    Full Text Available The requirement for the temperature stability is very high in the star sensors as the high precision needs for the altitude information. Thermal design and analysis thus is important for the high power star sensors and their supporters. CCD, normally with Peltier thermoelectric cooler (PTC, is the most important sensor component in the star sensors, which is also the main heat source in the star sensors suite. The major objective for the thermal design in this paper is to design a radiator to optimize the heat diffusion for CCD and PTC. The structural configuration of star sensors, the heat sources and orbit parameters were firstly introduced in this paper. The influences of the geometrical parameters and coating material characteristics of radiators on the heat diffusion were investigated by heat flux analysis. Carbon–carbon composites were then chosen to improve the thermal conductivity for the sensor supporters by studying the heat transfer path. The design is validated by simulation analysis and experiments on orbit. The satellite data show that the temperatures of three star sensors are from 17.8 °C to 19.6 °C, while the simulation results are from 18.1 °C to 20.1 °C. The temperatures of radiator are from 16.1 °C to 16.8 °C and the corresponding simulation results are from 16.0 °C to 16.5 °C. The temperature variety of each star sensor is less than 2 °C, which satisfies the design objectives.

  15. Electron Acceleration by High Power Radio Waves in the Ionosphere

    Science.gov (United States)

    Bernhardt, Paul

    2012-10-01

    At the highest ERP of the High Altitude Auroral Research Program (HAARP) facility in Alaska, high frequency (HF) electromagnetic (EM) waves in the ionosphere produce artificial aurora and electron-ion plasma layers. Using HAARP, electrons are accelerated by high power electrostatic (ES) waves to energies >100 times the thermal temperature of the ambient plasma. These ES waves are driven by decay of the pump EM wave tuned to plasma resonances. The most efficient acceleration process occurs near the harmonics of the electron cyclotron frequency in earth's magnetic field. Mode conversion plays a role in transforming the ES waves into EM signals that are recorded with ground receivers. These diagnostic waves, called stimulated EM emissions (SEE), show unique resonant signatures of the strongest electron acceleration. This SEE also provides clues about the ES waves responsible for electron acceleration. The electron gas is accelerated by high frequency modes including Langmuir (electron plasma), upper hybrid, and electron Bernstein waves. All of these waves have been identified in the scattered EM spectra as downshifted sidebands of the EM pump frequency. Parametric decay is responsible low frequency companion modes such as ion acoustic, lower hybrid, and ion Bernstein waves. The temporal evolution of the scattered EM spectrum indicates development of field aligned irregularities that aid the mode conversion process. The onset of certain spectral features is strongly correlated with glow plasma discharge structures that are both visible with the unaided eye and detectable using radio backscatter techniques at HF and UHF frequencies. The primary goals are to understand natural plasma layers, to study basic plasma physics in a unique ``laboratory with walls,'' and to create artificial plasma structures that can aid radio communications.

  16. Benefits of open and high-powered research outweigh costs.

    Science.gov (United States)

    LeBel, Etienne P; Campbell, Lorne; Loving, Timothy J

    2017-08-01

    Several researchers recently outlined unacknowledged costs of open science practices, arguing these costs may outweigh benefits and stifle discovery of novel findings. We scrutinize these researchers' (a) statistical concern that heightened stringency with respect to false-positives will increase false-negatives and (b) metascientific concern that larger samples and executing direct replications engender opportunity costs that will decrease the rate of making novel discoveries. We argue their statistical concern is unwarranted given open science proponents recommend such practices to reduce the inflated Type I error rate from .35 down to .05 and simultaneously call for high-powered research to reduce the inflated Type II error rate. Regarding their metaconcern, we demonstrate that incurring some costs is required to increase the rate (and frequency) of making true discoveries because distinguishing true from false hypotheses requires a low Type I error rate, high statistical power, and independent direct replications. We also examine pragmatic concerns raised regarding adopting open science practices for relationship science (preregistration, open materials, open data, direct replications, sample size); while acknowledging these concerns, we argue they are overstated given available solutions. We conclude benefits of open science practices outweigh costs for both individual researchers and the collective field in the long run, but that short term costs may exist for researchers because of the currently dysfunctional academic incentive structure. Our analysis implies our field's incentive structure needs to change whereby better alignment exists between researcher's career interests and the field's cumulative progress. We delineate recent proposals aimed at such incentive structure realignment. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  17. GaAs Substrates for High-Power Diode Lasers

    Science.gov (United States)

    Mueller, Georg; Berwian, Patrick; Buhrig, Eberhard; Weinert, Berndt

    GaAs substrate crystals with low dislocation density (Etch-Pit Density (EPD) ~10^18,^-3) are required for the epitaxial production of high-power diode-lasers. Large-size wafers (= 3 mathrm{in} -> >=3,) are needed for reducing the manufacturing costs. These requirements can be fulfilled by the Vertical Bridgman (VB) and Vertical Gradient Freeze (VGF) techniques. For that purpose we have developed proper VB/VGF furnaces and optimized the thermal as well as the physico-chemical process conditions. This was strongly supported by extensive numerical process simulation. The modeling of the VGF furnaces and processes was made by using a new computer code called CrysVUN++, which was recently developed in the Crystal Growth Laboratory in Erlangen.GaAs crystals with diameters of 2 and 3in were grown in pyrolytic Boron Nitride (pBN) crucibles having a small-diameter seed section and a conical part. Boric oxide was used to fully encapsulate the crystal and the melt. An initial silicon content in the GaAs melt of c (melt) = 3 x10^19,^-3 has to be used in order to achieve a carrier concentration of n = (0.8- 2) x10^18,^-3, which is the substrate specification of the device manufacturer of the diode-laser. The EPD could be reduced to values between 500,^-2 and 50,^-2 with a Si-doping level of 8 x10^17 to 1 x10^18,^-3. Even the 3in wafers have rather large dislocation-free areas. The lowest EPDs ( <100,^-2) are achieved for long seed wells of the crucible.

  18. State of the art in high-power microwaves: An overview

    Science.gov (United States)

    Swegle, J.; Benford, J.

    1993-12-01

    In the two decades since the presentation of the first experimental results, the study of high-power microwaves (HPM) has aimed at the production of microwave pulses with ever higher peak power and ever larger energy content. Drawing on the electrical pulsed power and relativistic electron beam technologies, a mix of sources have produced power levels in excess of 1 GW and pulse energies of ten to a thousand joules in both the centimeter and millimeter wavelength ranges. The potential for military applications of such powerful bursts became a major driving force for substantial research programs, and considerable advancements, in the United States and the former Soviet Union. The end of the Cold War and a reexamination of national priorities has diminished the momentum of military HPM development in these countries. Nevertheless, the field hasn't reached its limits, in capability or applicability, and one sees at present a diffusion of the technology across national borders. As examples, one sees commitments in the UK, France, and China to national programs aimed at the exploration of the defensive capabilities of HPM. The purpose of this paper will be to examine the state of the art in HPM at this juncture. We will look at: (1) Peak power production; (2) Pulse energy production and the phenomenon of pulse shortening at high peak power levels; (3) Coherent phasing of multiple high-power sources; (4) Compact HPM source development; and (5) Repetitive operation of sources. We will also briefly mention some emerging applications and offer some concluding thoughts.

  19. Diffraction Effects in Measurements of Characteristics of High-Power Microwave Pulses with Wide-Aperture Liquid Calorimeters

    Science.gov (United States)

    Klimov, A. I.; Tot'meninov, E. M.

    2017-10-01

    Numerical nonstationary simulation of diffraction by a quasi-plane three-layer wide-aperture absorbing loads of liquid calorimeters intended for measuring the energy of high-power microwave radiation pulses is performed using the electromagnetic code KARAT with application to the S-band. It is shown that these effects can cause significant distortion of the microwave pulse shape behind the load as well as underestimation of the measured energy by 10-20%.

  20. Thermal Response to High-Power Holmium Laser Lithotripsy.

    Science.gov (United States)

    Aldoukhi, Ali H; Ghani, Khurshid R; Hall, Timothy L; Roberts, William W

    2017-12-01

    The aim of this study was to investigate "caliceal" fluid temperature changes during holmium laser activation/lithotripsy using settings up to 40 W power output with different irrigation flow rates. The experimental system consisted of a glass test tube (diameter 10 mm/length 75 mm) filled with deionized water, to mimic a calix. Real-time temperature was recorded using a thermocouple (Physitemp, NJ) positioned 5 mm from the bottom of the tube. A 200 μm laser fiber (Flexiva; Boston Scientific, MA) was introduced through the working channel of a disposable ureteroscope (LithoVue; Boston Scientific) and the laser fiber tip was positioned 15 mm above the bottom of the test tube. Deionized water irrigation (room temperature) through the working channel of the ureteroscope was delivered at flow rates of 0, 7-8, 14-15, and 38-40 mL/minute. A 120-W holmium laser (pulse 120; Lumenis, CA) was used. The following settings were explored: 0.5 J × 10 Hz, 1.0 J × 10 Hz, 0.5 J × 20 Hz, 1.0 J × 20 Hz, 0.5 J × 40 Hz, 1.0 J × 40 Hz, and 0.5 J × 80 Hz. During each experiment, the laser was activated continuously for 60 seconds. Temperature increased with increasing laser power output and decreasing irrigation flow rate. The highest temperature, 70.3°C (standard deviation 2.7), occurred with laser setting of 1.0 J × 40 Hz and no irrigation after 60 seconds of continuous laser firing. None of the tested laser settings and irrigation parameters produced temperature exceeding 51°C when activated for only 10 seconds of continuous laser firing. High-power holmium settings fired in long bursts with low irrigation flow rates can generate high fluid temperatures in a laboratory "caliceal" model. Awareness of this risk allows urologist to implement a variety of techniques (higher irrigation flow rates, intermittent laser activation, and potentially cooled irrigation fluid) to control and mitigate thermal

  1. Interference effects at a dielectric plate applied as a high-power-laser attenuator.

    Science.gov (United States)

    Gregorcic, Peter; Babnik, Ales; Mozina, Janez

    2010-02-15

    The interference effects caused by the Fresnel reflections of a Gaussian beam on the boundaries of a dielectric plate, which can be considered as a Fabry-Perot etalon, were theoretically and experimentally investigated. In addition to the incident angle and the polarization of the incident light, two additional parameters--the plate's parallelism and the temperature--which are often neglected, were analyzed. Based on the theoretical predictions and the measured behavior of the transmittance of the dielectric plate a new, temperature-controlled variable high-power-laser attenuator is proposed. Unwanted changes in the plate's transmittance caused by the absorption of laser pulses within the plate are also presented. These phenomena are important in many applications where dielectric plates are used for a variety of purposes.

  2. Gyrotrons for High-Power Terahertz Science and Technology at FIR UF

    Science.gov (United States)

    Idehara, Toshitaka; Sabchevski, Svilen Petrov

    2017-01-01

    In this review paper, we present the recent progress in the development of a series of gyrotrons at the Research Center for Development of Far-Infrared Region, University of Fukui, that have opened the road to many novel applications in the high-power terahertz science and technology. The current status of the research in this actively developing field is illustrated by the most representative examples in which the developed gyrotrons are used as powerful and frequency-tunable sources of coherent radiation operating in a continuous-wave regime. Among them are high-precision spectroscopic techniques (most notably dynamic nuclear polarization-nuclear magnetic resonance, electron spin resonance, X-ray detected magnetic resonance, and studies of the hyperfine splitting of the energy levels of positronium), treatment and characterization of advanced materials, and new medical technologies.

  3. Stable high-power saturable absorber based on polymer-black-phosphorus films

    Science.gov (United States)

    Mao, Dong; Li, Mingkun; Cui, Xiaoqi; Zhang, Wending; Lu, Hua; Song, Kun; Zhao, Jianlin

    2018-01-01

    Black phosphorus (BP), a rising two-dimensional material with a layer-number-dependent direct bandgap of 0.3-1.5 eV, is very interesting for optoelectronics applications from near- to mid-infrared wavebands. In the atmosphere, few-layer BP tends to be oxidized or degenerated during interacting with lasers. Here, we fabricate few-layer BP nanosheets based on a liquid exfoliation method using N-methylpyrrolidone as the dispersion liquid. By incorporating BP nanosheets with polymers (polyvinyl alcohol or high-melting-point polyimide), two flexible filmy BP saturable absorbers are fabricated to realize passive mode locking in erbium-doped fiber lasers. The polymer-BP saturable absorber, especially the polyimide-BP saturable absorber, can prevent the oxidation or water-induced etching under high-power laser illuminations, providing a promising candidate for Q-switchers, mode lockers, and light modulators.

  4. Design of a high power, resonant converter for DC wind turbines

    DEFF Research Database (Denmark)

    Dincan, Catalin Gabriel; Kjær, Philip Carne; Chen, Yu-Hsing

    2018-01-01

    This paper presents a design procedure and loss estimation for a high power, medium voltage series resonant converter (entitled SRC#), intended for application in megawatt medium-voltage DC wind turbines. The converter is operated with a novel method of operation, entitled pulse removal technique......, characterized by variable frequency and phase shift modulation, below the resonant point of the LC tank. A step by step design procedure is proposed and circuit component ratings and efficiency are compared for two variants. The new method of operation reduces transformer size to below 50% while losses are kept...... below 1.5% from zero to nominal power, due to soft-switching characteristics. An experimental setup, rated for 10 kW and 5 kV output was assembled to extract losses and validate the semiconductor loss model....

  5. Phosphorus-doped silicon nanorod anodes for high power lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Chao Yan

    2017-01-01

    Full Text Available Heavy-phosphorus-doped silicon anodes were fabricated on CuO nanorods for application in high power lithium-ion batteries. Since the conductivity of lithiated CuO is significantly better than that of CuO, after the first discharge, the voltage cut-off window was then set to the range covering only the discharge–charge range of Si. Thus, the CuO core was in situ lithiated and acts merely as the electronic conductor in the following cycles. The Si anode presented herein exhibited a capacity of 990 mAh/g at the rate of 9 A/g after 100 cycles. The anode also presented a stable rate performance even at a current density as high as 20 A/g.

  6. A Lumped Thermal Model Including Thermal Coupling and Thermal Boundary Conditions for High Power IGBT Modules

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede

    2018-01-01

    Detailed thermal dynamics of high power IGBT modules are important information for the reliability analysis and thermal design of power electronic systems. However, the existing thermal models have their limits to correctly predict these complicated thermal behavior in the IGBTs: The typically used...... thermal model based on one-dimensional RC lumps have limits to provide temperature distributions inside the device, moreover some variable factors in the real-field applications like the cooling and heating conditions of the converter cannot be adapted. On the other hand, the more advanced three......-dimensional thermal models based on Finite Element Method (FEM) need massive computations, which make the long-term thermal dynamics difficult to calculate. In this paper, a new lumped three-dimensional thermal model is proposed, which can be easily characterized from FEM simulations and can acquire the critical...

  7. General 3D Lumped Thermal Model with Various Boundary Conditions for High Power IGBT Modules

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede

    2016-01-01

    Accurate thermal dynamics modeling of high power Insulated Gate Bipolar Transistor (IGBT) modules is important information for the reliability analysis and thermal design of power electronic systems. However, the existing thermal models have their limits to correctly predict these complicated...... thermal behaviors in the IGBTs. In this paper, a new three-dimensional (3D) lumped thermal model is proposed, which can easily be characterized from Finite Element Methods (FEM) based simulation and acquire the thermal distribution in critical points. Meanwhile the boundary conditions including...... the cooling system and power losses are modeled in the 3D thermal model, which can be adapted to different real field applications of power electronic converters. The accuracy of the proposed thermal model is verified by experimental results....

  8. Technological Breakthroughs in Growth Control of Silicon Carbide for High Power Electronic Devices

    Science.gov (United States)

    Matsunami, Hiroyuki

    2004-10-01

    Technological breakthroughs in growth control of SiC are reviewed. Step-controlled epitaxy by using off-axis SiC {0001} substrates to grow high-quality epitaxial layer is explained in detail. The introduction of substrate off-angles brings step-flow growth, which easily makes polytype replication of SiC at rather low temperatures. Off-angle dependence, rate-determining processes, and temperature dependence of growth rate are discussed. Prediction, whether step-flow growth or two-dimensional nucleation does occur, is given as a function of off-angle, growth temperature, and growth rate. Optical and electrical properties of undoped epitaxial layers are characterized. Impurity doping during the growth is explained. Recent progresses in peripheral technologies for realization of power electronic devices, such as bulk growth, epitaxial growth, ion implantation, MOS interface, ohmic contacts, are introduced. Finally application to high-power electronic devices is briefly described.

  9. High power free space optical link for rapid energy and data transmission

    Science.gov (United States)

    Dhadwal, Harbans S.; Rastegar, Jahangir; Feng, Dake; Kwok, Philip

    2016-05-01

    Design and experimental data for a high power laser diode based free space point-to-point optical power/data link is presented. In time critical power up applications, such as providing power and guidance information to a munition shell just prior to deployment, energy of the order of 100 J needs to be transferred in under 10 s. Current inductive technology is slow and broadcasts a radio-frequency signal which is undesirable for stealth operation. Rapid energy transfer times require high irradiance levels at the surface of the photovoltaic cells, typically, exceeding 1000X suns. Through efficient thermal design of heat sinks, high optical to electrical power conversion efficiencies of 50%, which are usually attainable at low power levels of 1 W, are achievable at higher power levels.

  10. High power, medium voltage, series resonant converter for DC wind turbines

    DEFF Research Database (Denmark)

    Dincan, Catalin Gabriel; Kjær, Philip Carne; Chen, Yu-Hsing

    2017-01-01

    A new modulation scheme is introduced for a single-phase series-resonant converter, which permits continuous regulation of power from nominal level to zero, in presence of variable input and output dc voltage levels. Rearranging the circuit to locate the resonant LC tank on the rectifier side...... of the high turns-ratio transformer combined with frequency control and phase-shifted inverter modulation keep transformer flux constant from nominal frequency down to DC, always in sub-resonant continuous or discontinuous conduction mode. This overcomes the principal deficit of series-resonant converters......, and the resulting compact and efficient transformer, and soft-commutated inverter, present particular advantages in high-power, high-voltage applications, like DC offshore wind turbines. With transformer excitation frequency in hundreds of Hz range, line-frequency diodes can be employed in the high-voltage...

  11. Process control in continuous high-power CO2 laser beam welding

    Science.gov (United States)

    Seidel, Bernd; Beersiek, Jorg; Beyer, Eckhard

    1994-09-01

    The use of high power CO2 lasers in welding enables processing with high laser intensities at the workpiece which is connected with the formation of a laser induced plasma at the surface of the workpiece. Therefore the effect of deep penetration welding by formation of a plasma filled keyhole and plasma plume above the workpiece is possible, including the risk of plasma shielding, which means strong absorption of the incident laser beam above the workpiece and thus interruption of the welding process. The conditions for ignition of plasma shielding, which is determined by electron density, are mainly influenced by laser intensity, process gas and material. Variations of these parameters have been conducted in order to find limits for the appearance of plasma shielding. Experimental data are used to verify a model concerning the absorption mechanism of a stationary shielding plasma state. The dynamic behavior is treated by time resolved spectroscopic analysis of the light emitted by the plasma above the workpiece yielding monitoring signals that have a strong correlation with the formation of plasma shielding. Based on these investigations a closed-loop process control in continuous high power laser welding has been developed. Using the intensity of a spectral line of laser induced plasma as monitoring signal and the regulation of laser intensity via laser power, plasma shielding can be suppressed. From the industrial point of view increase in economy and reliability of the laser welding process combined with quality improvements which are induced by the application of the plasma shielding controller (PSC) are of great importance. For this reason three examples of PSC application are presented.

  12. High power compatible internally sensed optical phased array

    National Research Council Canada - National Science Library

    Roberts, Lyle E; Ward, Robert L; Francis, Samuel P; Sibley, Paul G; Fleddermann, Roland; Sutton, Andrew J; Smith, Craig; McClelland, David E; Shaddock, Daniel A

    2016-01-01

    .... One important application of an OPA is coherent beam combining (CBC), which can be used to create beams of higher power than is possible with a single laser source, especially for narrow linewidth sources...

  13. Coherent beam combiner for a high power laser

    Science.gov (United States)

    Dane, C. Brent; Hackel, Lloyd A.

    2002-01-01

    A phase conjugate laser mirror employing Brillouin-enhanced four wave mixing allows multiple independent laser apertures to be phase locked producing an array of diffraction-limited beams with no piston phase errors. The beam combiner has application in laser and optical systems requiring high average power, high pulse energy, and low beam divergence. A broad range of applications exist in laser systems for industrial processing, especially in the field of metal surface treatment and laser shot peening.

  14. Does hypericin boost the efficacy of high-power laser? A preliminary experimental study on rats.

    Science.gov (United States)

    Zor, Murat; Goktas, Serdar; Yildirim, Ibrahim; Zorba, Unal Orhan; Basal, Seref; Alp, Bilal Firat; Kaya, Engin; Erogul, Osman

    2014-12-01

    Lasers are widely used in treating symptomatic benign prostatic hyperplasia. In current practice, potassium titanyl phosphate (KTP) lasers are the most common type of laser systems used. The aim here was to evaluate the rapid effect of high-power laser systems after application of hypericin. Experimental animal study conducted in the Department of Urology, Gülhane Military Medical Academy, Ankara, Turkey, in 2012. Sixteen rats were randomized into four groups: 120 W KTP laser + hypericin; 120 W KTP laser alone; 80 W KTP laser + hypericin; and 80 W KTP laser alone. Hypericin was given intraperitoneally two hours prior to laser applications. The laser incisions were made through the quadriceps muscle of the rats. The depth and the width of the laser incisions were evaluated histologically and recorded. To standardize the effects of the laser, we used the ratio of depth to width. These new values showed us the depth of the laser application per unit width. The new values acquired were evaluated statistically. Mean depth/width values were 231.6, 173.6, 214.1 and 178.9 in groups 1, 2, 3 and 4, respectively. The most notable result was that higher degrees of tissue penetration were achieved in the groups with hypericin (P laser applications.

  15. High-Powered, Ultrasonically Assisted Thermal Stir Welding

    Science.gov (United States)

    Ding, Robert

    2013-01-01

    distance equal to the thickness of the material being welded. The TSW process can be significantly improved by reducing the draw forces. This can be achieved by reducing the friction forces between the weld workpieces and the containment plates. High-power ultrasonic (HPU) vibrations of the containment plates achieve friction reduction in the TSW process. Furthermore, integration of the HPU energy into the TSW stir rod can increase tool life of the stir rod, and can reduce shear forces to which the stir rod is subjected during the welding process. TSW has been used to successfully join 0.500-in (˜13-mm) thick commercially pure (CP) titanium, titanium 6AL- 4V, and titanium 6AL-4V ELI in weld joint lengths up to 9 ft (˜2.75-m) long. In addition, the TSW process was used to fabricate a sub-scale hexagonally shaped gun turret component for the U.S. Navy. The turret is comprised of six 0.5000-in (˜13-mm) thick angled welds. Each angled weld joint was prepared by machining the mating surfaces to 120deg. The angled weld joint was then fixtured using an upper and lower containment plate of the same geometry of the angled weld joint. The weld joint was then stirred by the stir rod as it and the upper and lower containment plates traverse through the angled joint prep.

  16. Method and apparatus for delivering high power laser energy over long distances

    Science.gov (United States)

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2015-04-07

    Systems, devices and methods for the transmission and delivery of high power laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser drilling of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates.

  17. Use of high-power diode lasers for hardening and thermal conduction welding of metals

    Science.gov (United States)

    Klocke, Fritz; Demmer, Axel; Zaboklicki, A.

    1997-08-01

    CO2 and Nd:YAG high power lasers have become established as machining tools in industrial manufacturing over the last few years. The most important advantages compared to conventional processing techniques lie in the absence of forces introduced by the laser into the workpiece and in the simple arid highly accurate control in terms ofpositioning and timing making the laser a universally applicable, wear-free and extremely flexible tool /1,2/. The laser can be utilised costeffectively in numerous manufacturing processes but there are also further applications for the laser which produce excellent results from a technical point of view, but are not justified in terms of cost. The extensive use of lasers, particularly in small companies and workshops, is hindered by two main reasons: the complexity and size ofthe laser source and plant and the high investment costs /3/. A new generation of lasers, the high power diode lasers (HDL), combines high performance with a compact design, making the laser a cheap and easy to use tool with many applications /3,4,5,6/. In the diode laser, the laser beam is generated by a microelectronic diode which transforms electrical energy directly into laser energy. Diode lasers with low power outputs have, for some time, been making their mark in our everyday lives: they are used in CD players, laser printers and scanners at cash tills. Modern telecommunications would be impossible without these lasers which enable information to be transmitted in the form oflight impulses through optical fibres. They can also be found in compact precision measurement instrumentation - range fmders, interferometers and pollutant analysis devices /3,6/. In the field of material processing, the first applications ofthe laser, such as for soldering, inscribing, surface hardening and plastic or heat conduction welding, will exceed the limits ofthe relatively low performance output currently available. The diode laser has a shorter wavelength than the CO2 and

  18. Force sharing in high-power parallel servo-actuators

    Science.gov (United States)

    Neal, T. P.

    1974-01-01

    The various existing force sharing schemes were examined by conducting a literature survey. A list of potentially applicable concepts was compiled from this survey, and a brief analysis was then made of each concept, which resulted in two competing schemes being selected for in-depth evaluation. A functional design of the equalization logic for the two schemes was undertaken and specific space shuttle application was chosen for experimental evaluation. The application was scaled down so that existing hardware could be utilized. Next, an analog computer study was conducted to evaluate the more important characteristics of the two competing force sharing schemes. On the basis of the computers study, a final configuration was selected. A load simulator was then designed to evaluate this configuration on actual hardware.

  19. High-power, military ruggedized QCL-based laser systems

    Science.gov (United States)

    Takeuchi, Eric B.; Chapman, William B.; Arnone, David; Pushkarsky, Michael; Lopez, Enrique; Young, Michael; Caffey, Dave; Borgardt, Brandon; Priest, Allen; Sensibaugh, Jason; Day, Timothy

    2012-06-01

    Daylight Solutions has pioneered the development and commercialization of quantum cascade laser (QCL) technology for commercial and military markets. Multi-Watt, multi-wavelength QCL-based systems have been manufactured and tested against harsh military environmental requirements for military applications. These self-contained, turn-key systems have been designed to comply with modular open system architecture (MOSA) principles, and have been proven in several different system geometries. This paper will highlight the environmental requirements imposed upon, and performance from, QCL-based laser systems for example military applications.

  20. Transmission line pulse system for avalanche characterization of high power semiconductor devices

    Science.gov (United States)

    Riccio, Michele; Ascione, Giovanni; De Falco, Giuseppe; Maresca, Luca; De Laurentis, Martina; Irace, Andrea; Breglio, Giovanni

    2013-05-01

    Because of the increasing in power density of electronic devices for medium and high power application, reliabilty of these devices is of great interest. Understanding the avalanche behaviour of a power device has become very important in these last years because it gives an indication of the maximum energy ratings which can be seen as an index of the device ruggedness. A good description of this behaviour is given by the static IV blocking characteristc. In order to avoid self heating, very relevant in high power devices, very short pulses of current have to be used, whose value can change from few milliamps up to tens of amps. The most used method to generate short pulses is the TLP (Transmission Line Pulse) test, which is based on charging the equivalent capacitance of a transmission line to high value of voltage and subsequently discharging it onto a load. This circuit let to obtain very short square pulses but it is mostly used for evaluate the ESD capability of semiconductor and, in this environment, it generates pulses of low amplitude which are not high enough to characterize the avalanche behaviour of high power devices . Advanced TLP circuit able to generate high current are usually very expensive and often suffer of distorption of the output pulse. In this article is proposed a simple, low cost circuit, based on a boosted-TLP configuration, which is capable to produce very square pulses of about one hundreds of nanosecond with amplitude up to some tens of amps. A prototype is implemented which can produce pulses up to 20A of amplitude with 200 ns of duration which can characterize power devices up to 1600V of breakdown voltage. Usage of microcontroller based logic make the circuit very flexible. Results of SPICE simulation are provided, together with experimental results. To prove the effectiveness of the circuit, the I-V blocking characteristics of two commercial devices, namely a 600V PowerMOS and a 1200V Trench-IGBT, are measured at different

  1. A 380 V High Efficiency and High Power Density Switched-Capacitor Power Converter using Wide Band Gap Semiconductors

    DEFF Research Database (Denmark)

    Fan, Lin; Knott, Arnold; Jørgensen, Ivan Harald Holger

    2018-01-01

    to compose the proposed power stage. Their switching and loss characteristics are analyzed with transient waveforms and thermal images. Different isolated driving circuits are compared and a compact isolated halfbridge driving circuit is proposed. The full-load efficiencies of 98.3% and 97.6% are achieved......State-of-the-art switched-capacitor DC-DC power converters mainly focus on low voltage and/or high power applications. However, at high voltage and low power levels, new designs are anticipated to emerge and a power converter that has both high efficiency and high power density is highly desirable....... This paper presents such a high voltage low power switched-capacitor DC-DC converter with an input voltage upto 380 V (compatible with rectified European mains) and an output power experimentally validated up to 21.3 W. The wideband gap semiconductor devices of GaN switches and SiC diodes are combined...

  2. High Power Electronics - Key Technology for Wind Turbines

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Ma, Ke

    2014-01-01

    reliability challenges for the future wind turbines are explained. It is concluded that the wind turbine behavior/performance can be significantly improved by introducing power electronics, and there will be higher requirements for the power electronics performances in wind power application....

  3. High power electron and ion beam research and technology

    Energy Technology Data Exchange (ETDEWEB)

    Nation, J.A.; Sudan, R.N. (eds.)

    1977-01-01

    Topics covered in volume II include: collective accelerators; microwaves and unneutralized E-beams; technology of high-current E-beam accelerators and laser applications of charged-particle beams. Abstracts of twenty-nine papers from the conference were prepared for the data base in addition to six which appeared previously. (GHT)

  4. Single phase forced convection cooling of high power leds

    NARCIS (Netherlands)

    Ozdemir, M.Z.; Chestakov, D.; Frijns, A.J.H.

    2011-01-01

    LEDs are strong candidates for future illumination applications dueto their much lower consumption of energy compared to conventional lighting options. One of key problems in development of LEDs is successful thermal management during illumination. Therefore, current research ongoing related to high

  5. High power terahertz induced carrier multiplication in Silicon

    DEFF Research Database (Denmark)

    Tarekegne, Abebe Tilahun; Pedersen, Pernille Klarskov; Iwaszczuk, Krzysztof

    2015-01-01

    The application of an intense THz field results a nonlinear transmission in high resistivity silicon. Upon increasing field strength, the transmission falls from 70% to 62% due to carrier generation through THz-induced impact ionization and subsequent absorption of the THz field by free electrons....

  6. A thermally-invariant, additively manufactured, high-power graphene resistor for flexible electronics

    Science.gov (United States)

    Michel, Monica; Biswas, Chandan; Tiwary, Chandra S.; Saenz, Gustavo A.; Hossain, Ridwan F.; Ajayan, Pulickel; Kaul, Anupama B.

    2017-06-01

    Solution processed two-dimensional (2D) layered materials and their integration with additive manufacturing techniques, such as ink-jet printing, is a facile approach for incorporating these exotic materials into device platforms for flexible electronics. In this work, graphene ink formulations are successfully utilized toward the design and fabrication of high-power resistive structures that are printed on both rigid and flexible substrates and have the potential to deliver close to 10 W of power. A near-flat, negative temperature coefficient of resistivity (TCR) is measured with an activation energy E a ~ 2.4 meV for electron hopping, which is 100×  lower compared to E a values for high TCR materials. The TCR and E a values are amongst the lowest reported for 2D layered material systems. The thermal-invariance of resistivity for such high-power graphene printed resistors is attractive for applications, for example to provide a stable heating source for flexible electronics over extreme thermal environments. The transport characteristics of the ink-jet printed features is modeled as a composite structure in order to explain the thermal response which appears to be mediated via defects in the sonicated graphite, and correlates well to inferences made from Raman spectroscopy and transmission electron microscopy analysis conducted on the printed graphene structures. In order to fabricate such functional structures with ink-jet printing, the active nozzle number, printing passes, and annealing conditions are shown to play an important role to determine line resolution, and also dictate the morphological and electronic transport characteristics of the printed graphene features.

  7. LEO to GEO (and Beyond) Transfers Using High Power Solar Electric Propulsion (HP-SEP)

    Science.gov (United States)

    Loghry, Christopher S.; Oleson, Steven R.; Woytach, Jeffrey M.; Martini, Michael C.; Smith, David A.; Fittje, James E.; Gyekenyesi, John Z.; Colozza, Anthony J.; Fincannon, James; Bogner, Aimee; hide

    2017-01-01

    Rideshare, or Multi-Payload launch configurations, are becoming more and more commonplace but access to space is only one part of the overall mission needs. The ability for payloads to achieve their target orbits or destinations can still be difficult and potentially not feasible with on-board propulsion limitations. The High Power Solar Electric Propulsion (HP-SEP) Orbital Maneuvering Vehicle (OMV) provides transfer capabilities for both large and small payload in excess of what is possible with chemical propulsion. Leveraging existing secondary payload adapter technology like the ESPA provides a platform to support Multi-Payload launch and missions. When coupled with HP-SEP, meaning greater than 30 kW system power, very large delta-V maneuvers can be accomplished. The HP-SEP OMV concept is designed to perform a Low Earth Orbit to Geosynchronous Orbit (LEO-GEO) transfer of up to six payloads each with 300kg mass. The OMV has enough capability to perform this 6 kms maneuver and have residual capacity to extend an additional transfer from GEO to Lunar orbit. This high deltaV capability is achieved using state of the art 12.5kW Hall Effect Thrusters (HET) coupled with high power roll up solar arrays. The HP-SEP OMV also provides a demonstration platform for other SEP technologies such as advanced Power Processing Units (PPU), Xenon Feed Systems (XFS), and other HET technologies. The HP-SEP OMV platform can be leveraged for other missions as well such as interplanetary science missions and applications for resilient space architectures.

  8. Globally Stable Microresonator Turing Pattern Formation for Coherent High-Power THz Radiation On-Chip

    Science.gov (United States)

    Huang, Shu-Wei; Yang, Jinghui; Yang, Shang-Hua; Yu, Mingbin; Kwong, Dim-Lee; Zelevinsky, T.; Jarrahi, Mona; Wong, Chee Wei

    2017-10-01

    In nonlinear microresonators driven by continuous-wave (cw) lasers, Turing patterns have been studied in the formalism of the Lugiato-Lefever equation with emphasis on their high coherence and exceptional robustness against perturbations. Destabilization of Turing patterns and the transition to spatiotemporal chaos, however, limit the available energy carried in the Turing rolls and prevent further harvest of their high coherence and robustness to noise. Here, we report a novel scheme to circumvent such destabilization, by incorporating the effect of local mode hybridizations, and we attain globally stable Turing pattern formation in chip-scale nonlinear oscillators with significantly enlarged parameter space, achieving a record-high power-conversion efficiency of 45% and an elevated peak-to-valley contrast of 100. The stationary Turing pattern is discretely tunable across 430 GHz on a THz carrier, with a fractional frequency sideband nonuniformity measured at 7.3 ×10-14 . We demonstrate the simultaneous microwave and optical coherence of the Turing rolls at different evolution stages through ultrafast optical correlation techniques. The free-running Turing-roll coherence, 9 kHz in 200 ms and 160 kHz in 20 minutes, is transferred onto a plasmonic photomixer for one of the highest-power THz coherent generations at room temperature, with 1.1% optical-to-THz power conversion. Its long-term stability can be further improved by more than 2 orders of magnitude, reaching an Allan deviation of 6 ×10-10 at 100 s, with a simple computer-aided slow feedback control. The demonstrated on-chip coherent high-power Turing-THz system is promising to find applications in astrophysics, medical imaging, and wireless communications.

  9. A novel "gain chip" concept for high-power lasers (Conference Presentation)

    Science.gov (United States)

    Li, Min; Li, Mingzhong; Wang, Zhenguo; Yan, Xiongwei; Jiang, Xinying; Zheng, Jiangang; Cui, Xudong; Zhang, Xiaomin

    2017-05-01

    High-power lasers, including high-peak power lasers (HPPL) and high-average power lasers (HAPL), attract much interest for enormous variety of applications in inertial fusion energy (IFE), materials processing, defense, spectroscopy, and high-field physics research. To meet the requirements of high efficiency and quality, a "gain chip" concept is proposed to properly design the pumping, cooling and lasing fields. The gain chip mainly consists of the laser diode arrays, lens duct, rectangle wave guide and slab-shaped gain media. For the pumping field, the pump light will be compressed and homogenized by the lens duct to high irradiance with total internal reflection, and further coupled into the gain media through its two edge faces. For the cooling field, the coolant travels along the flow channel created by the adjacent slabs in the other two edge-face direction, and cool the lateral faces of the gain media. For the lasing field, the laser beam travels through the lateral faces and experiences minimum thermal wavefront distortions. Thereby, these three fields are in orthogonality offering more spatial freedom to handle them during the construction of the lasers. Transverse gradient doping profiles for HPPL and HAPL have been employed to achieve uniform gain distributions (UGD) within the gain media, respectively. This UGD will improve the management for both amplified spontaneous emission (ASE) and thermal behavior. Since each "gain chip" has its own pump source, power scaling can be easily achieved by placing identical "gain chips" along the laser beam axis without disturbing the gain and thermal distributions. To detail our concept, a 1-kJ pulsed amplifier is designed and optical-to-optical efficiency up to 40% has been obtained. We believe that with proper coolant (gas or liquid) and gain media (Yb:YAG, Nd:glass or Nd:YAG) our "gain chip" concept might provide a general configuration for high-power lasers with high efficiency and quality.

  10. Globally Stable Microresonator Turing Pattern Formation for Coherent High-Power THz Radiation On-Chip

    Directory of Open Access Journals (Sweden)

    Shu-Wei Huang

    2017-10-01

    Full Text Available In nonlinear microresonators driven by continuous-wave (cw lasers, Turing patterns have been studied in the formalism of the Lugiato-Lefever equation with emphasis on their high coherence and exceptional robustness against perturbations. Destabilization of Turing patterns and the transition to spatiotemporal chaos, however, limit the available energy carried in the Turing rolls and prevent further harvest of their high coherence and robustness to noise. Here, we report a novel scheme to circumvent such destabilization, by incorporating the effect of local mode hybridizations, and we attain globally stable Turing pattern formation in chip-scale nonlinear oscillators with significantly enlarged parameter space, achieving a record-high power-conversion efficiency of 45% and an elevated peak-to-valley contrast of 100. The stationary Turing pattern is discretely tunable across 430 GHz on a THz carrier, with a fractional frequency sideband nonuniformity measured at 7.3×10^{−14}. We demonstrate the simultaneous microwave and optical coherence of the Turing rolls at different evolution stages through ultrafast optical correlation techniques. The free-running Turing-roll coherence, 9 kHz in 200 ms and 160 kHz in 20 minutes, is transferred onto a plasmonic photomixer for one of the highest-power THz coherent generations at room temperature, with 1.1% optical-to-THz power conversion. Its long-term stability can be further improved by more than 2 orders of magnitude, reaching an Allan deviation of 6×10^{−10} at 100 s, with a simple computer-aided slow feedback control. The demonstrated on-chip coherent high-power Turing-THz system is promising to find applications in astrophysics, medical imaging, and wireless communications.

  11. High-power handling, ultra-fast, GRIN lens-coupled photodetectors

    Science.gov (United States)

    Joshi, Abhay; Becker, Don; Datta, Shubhashish

    2008-04-01

    The performance of microwave photonic systems can be improved by utilizing high power handling photodetectors. Operation at higher photocurrents enables larger output RF signals to be produced directly by the photodetector. This reduces the requirement of signal amplification by RF amplifiers, thereby simultaneously improving the dynamic range and the noise figure. In optical coherent systems, high power handling photodetectors enable operation at high local oscillator power levels to boost the coherent gain and the detection sensitivity. Thus, techniques to enhance the power handling capability of photodetectors are of interest for both free space and fiber based applications. Photodetector current saturates at high optical power levels due to space-charge screening effect. The saturation effect is maximized where the illumination intensity, and the resulting photocurrent density, is largest. In this work, we focus on optimizing the optical field profile incident on top-illuminated InGaAs photodiodes to minimize the peak photocurrent density. This was achieved by employing graded-index (GRIN) lens coupling to uniformly distribute the optical power across the diode cross-section. We demonstrate 5dB improvement in photodiode's power handling capability and linearity by employing GRIN lens coupling as compared to single mode fiber (SMF) coupling. Our GRIN lens-coupled photodetectors have achieved small-signal 1dB compression current of >50mA and 12.5dBm amplifier-free RF output. These devices also exhibit linear behavior for a peak-to-peak RF pulse output of >2.5V, at ~30ps pulse width. This constitutes a 100% improvement over SMF coupled devices. Further, the GRIN photodiodes demonstrate pulse broadening =0.65ps/mW, as compared to 2ps/mW for SMF devices.

  12. High-power 100-fs SESAM-modelocked VESCEL (Conference Presentation)

    Science.gov (United States)

    Waldburger, Dominik; Link, Sandro M.; Alfieri, Cesare G. E.; Golling, Matthias; Keller, Ursula

    2017-03-01

    Ultrafast vertical external-cavity surface-emitting lasers (VECSELs) are versatile laser sources and feature high-power operation. To date the best modelocking results have been achieved with a semiconductor saturable absorber mirror (SESAM). Ultrafast optically pumped semiconductor disk lasers (SDLs) are compact, cost-efficient and provide excellent beam quality at gigahertz pulse repetition rates for applications such as for example multi-photon imaging, ultrafast communication and in particular self-referenced gigahertz frequency combs. The highest peak power obtained with an ultrafast VECSEL is 4.35 kW in 400-fs pulses and the shortest pulses until now are 107 fs at 3 mW average output power. Here we present a SESAM-modelocked VECSEL with pulses as short as 96 fs and 100 mW average output power. These are to the best of our knowledge the shortest pulses achieved by a fundamentally modelocked SDL and result in a very high peak power of 0.56 kW at a pulse repetition rate of 1.63 GHz. The short pulse duration was achieved by introducing a small amount of positive group delay dispersion with a single path through an external 2-mm thick ZnSe window plate that compensated the initially negatively chirped 107-fs output pulses. Currently the power is limited by the transition from fundamental modelocking to multi-pulse operation, which reduces the pulse peak power and introduces additional noise. Therefore, we present a study of the multi-pulse behavior of the high-power 100-fs SDL resulting from the complex modelocking mechanism. This study also provides an insight into special issues of pulse characterization that may suggest stable fundamental modelocking even if this is not the case.

  13. Numerical investigation on high power mid-infrared supercontinuum fiber lasers pumped at 3 µm.

    Science.gov (United States)

    Wei, Chen; Zhu, Xiushan; Norwood, Robert A; Song, Feng; Peyghambarian, N

    2013-12-02

    High power mid-infrared (mid-IR) supercontinuum (SC) laser sources in the 3-12 µm region are of great interest for a variety of applications in many fields. Although various mid-IR SC laser sources have been proposed and investigated experimentally and theoretically in the past several years, power scaling of mid-IR SC lasers beyond 3 μm with infrared edges extending beyond 7 μm are still challenges because the wavelengths of most previously used pump sources are below 2 μm. These problems can be solved with the recent development of mode-locked fiber lasers at 3 μm. In this paper, high power mid-IR SC laser sources based on dispersion engineered tellurite and chalcogenide fibers and pumped by ultrafast lasers at 3 µm are proposed and investigated. Our simulation results show that, when a W-type tellurite fiber with a zero dispersion wavelength (ZDW) of 2.7 µm is pumped at 2.78 μm, the power proportion of the SC laser beyond 3 µm can exceed 40% and the attainable SC output power of the proposed solid-cladding tellurite fiber is one order of magnitude higher than that of existing microstructured tellurite fibers. Our calculation also predicts that a very promising super-broadband mid-IR SC fiber laser source covering two atmospheric windows and molecules' "fingerprint" region can be obtained with a microstructured As2Se3 chalcogenide fiber pumped at 2.78 μm.

  14. Laser processes and analytics for high power 3D battery materials

    Science.gov (United States)

    Pfleging, W.; Zheng, Y.; Mangang, M.; Bruns, M.; Smyrek, P.

    2016-03-01

    Laser processes for cutting, modification and structuring of energy storage materials such as electrodes, separator materials and current collectors have a great potential in order to minimize the fabrication costs and to increase the performance and operational lifetime of high power lithium-ion-batteries applicable for stand-alone electric energy storage devices and electric vehicles. Laser direct patterning of battery materials enable a rather new technical approach in order to adjust 3D surface architectures and porosity of composite electrode materials such as LiCoO2, LiMn2O4, LiFePO4, Li(NiMnCo)O2, and Silicon. The architecture design, the increase of active surface area, and the porosity of electrodes or separator layers can be controlled by laser processes and it was shown that a huge impact on electrolyte wetting, lithium-ion diffusion kinetics, cell life-time and cycling stability can be achieved. In general, the ultrafast laser processing can be used for precise surface texturing of battery materials. Nevertheless, regarding cost-efficient production also nanosecond laser material processing can be successfully applied for selected types of energy storage materials. A new concept for an advanced battery manufacturing including laser materials processing is presented. For developing an optimized 3D architecture for high power composite thick film electrodes electrochemical analytics and post mortem analytics using laser-induced breakdown spectroscopy were performed. Based on mapping of lithium in composite electrodes, an analytical approach for studying chemical degradation in structured and unstructured lithium-ion batteries will be presented.

  15. High-power MIXSEL: an integrated ultrafast semiconductor laser with 6.4 W average power.

    Science.gov (United States)

    Rudin, B; Wittwer, V J; Maas, D J H C; Hoffmann, M; Sieber, O D; Barbarin, Y; Golling, M; Südmeyer, T; Keller, U

    2010-12-20

    High-power ultrafast lasers are important for numerous industrial and scientific applications. Current multi-watt systems, however, are based on relatively complex laser concepts, for example using additional intracavity elements for pulse formation. Moving towards a higher level of integration would reduce complexity, packaging, and manufacturing cost, which are important requirements for mass production. Semiconductor lasers are well established for such applications, and optically-pumped vertical external cavity surface emitting lasers (VECSELs) are most promising for higher power applications, generating the highest power in fundamental transverse mode (>20 W) to date. Ultrashort pulses have been demonstrated using passive modelocking with a semiconductor saturable absorber mirror (SESAM), achieving for example 2.1-W average power, sub-100-fs pulse duration, and 50-GHz pulse repetition rate. Previously the integration of both the gain and absorber elements into a single wafer was demonstrated with the MIXSEL (modelocked integrated external-cavity surface emitting laser) but with limited average output power (power scaling concept of the MIXSEL using optimized quantum dot saturable absorbers in an antiresonant structure design combined with an improved thermal management by wafer removal and mounting of the 8-µm thick MIXSEL structure directly onto a CVD-diamond heat spreader. The simple straight cavity with only two components has generated 28-ps pulses at 2.5-GHz repetition rate and an average output power of 6.4 W, which is higher than for any other modelocked semiconductor laser.

  16. Creation of visible artificial optical emissions in the aurora by high-power radio waves

    Science.gov (United States)

    Pedersen, Todd. R.; Gerken, Elizabeth A.

    2005-02-01

    Generation of artificial light in the sky by means of high-power radio waves interacting with the ionospheric plasma has been envisaged since the early days of radio exploration of the upper atmosphere, with proposed applications ranging from regional night-time street lighting to atmospheric measurements. Weak optical emissions have been produced for decades in such ionospheric `heating' experiments, where they serve as key indicators of electron acceleration, thermal heating, and other effects of incompletely understood wave-particle interactions in the plasma under conditions difficult to replicate in the laboratory. The extremely low intensities produced previously have, however, required sensitive instrumentation for detection, preventing applications beyond scientific research. Here we report observations of radio-induced optical emissions bright enough to be seen by the naked eye, and produced not in the quiet mid-latitude ionosphere, but in the midst of a pulsating natural aurora. This may open the door to visual applications of ionospheric heating technology or provide a way to probe the dynamics of the natural aurora and magnetosphere.

  17. AlGaInN laser diode bars for high-power, optical integration and quantum technologies

    Science.gov (United States)

    Najda, S. P.; Perlin, P.; Suski, T.; Marona, L.; Stanczyk, S.; Wisniewski, P.; Czernecki, R.; Schiavon, D.; Leszczyński, M.

    2017-05-01

    GaN laser diodes fabricated from the AlGaInN material system is an emerging technology for high power, optical integration and quantum applications. The AlGaInN material system allows for laser diodes to be fabricated over a very wide range of wavelengths from u.v., 380nm, to the visible 530nm, by tuning the indium content of the laser GaInN quantum well, giving rise to new and novel applications including displays and imaging systems, free-space and underwater telecommunications and the latest quantum technologies such as optical atomic clocks and atom interferometry.

  18. A Wide-Band High-Gain Compact SIS Receiver Utilizing a 300-μW SiGe IF LNA

    Science.gov (United States)

    Montazeri, Shirin; Grimes, Paul K.; Tong, Cheuk-Yu Edward; Bardin, Joseph C.

    2017-06-01

    Low-power low-noise amplifiers integrated with superconductor-insulator-superconductor (SIS) mixers are required to enable implementation of large-scale focal plane arrays. In this work, a 220-GHz SIS mixer has been integrated with a high-gain broad-band low-power IF amplifier into a compact receiver module. The low noise amplifier (LNA) was specifically designed to match to the SIS output impedance and contributes less than 7 K to the system noise temperature over the 4-8 GHz IF frequency range. A receiver noise temperature of 30-45 K was measured for a local oscillator frequency of 220 GHz over an IF spanning 4-8 GHz. The LNA power dissipation was only 300-μW. To the best of the authors' knowledge, this is the lowest power consumption reported for a high-gain wide-band LNA directly integrated with an SIS mixer.

  19. High-temperature alloys for high-power thermionic systems

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Kwang S.; Jacobson, D.L.; D' cruz, L.; Luo, Anhua; Chen, Bor-Ling.

    1990-08-01

    The need for structural materials with useful strength above 1600 k has stimulated interest in refractory-metal alloys. Tungsten possesses an extreme high modulus of elasticity as well as the highest melting temperature among metals, and hence is being considered as one of the most promising candidate materials for high temperature structural applications such as space nuclear power systems. This report is divided into three chapters covering the following: (1) the processing of tungsten base alloys; (2) the tensile properties of tungsten base alloys; and (3) creep behavior of tungsten base alloys. Separate abstracts were prepared for each chapter. (SC)

  20. High power, diode pumped Er:YAG for dentistry

    Science.gov (United States)

    Hagen, C.; Heinrich, A.; Nussbaumer, B.

    2011-03-01

    Pantec Medical Laser presents a diode pumped Er:YAG laser for dental and hard tissue applications. The diode pumped laser is practically maintenance free and ensures reliable operation over several thousand hours. The high repetition rate with up to 15 W average output power, allows treatments otherwise not feasible with low repetition rate, lamp pumped Er:YAG systems. The variable pulse duration of 10 to 200 μs combined with the good beam quality ensures precise and fast treatment. First results on enamel ablation as well as the power scalability of the technology to 200 mJ and 30 W average power are also shown.