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Sample records for high-power gyrotron oscillators

  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. 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.

  3. Development of Long Pulse and High Power 170GHz Gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Keishi; Kasugai, Atsushi; Minami, Ryutaro; Takahashi, Koji; Kobayashi, Noriyuki [Plasma heating Laboratory, Japan Atomic Energy Research Institute (JAERI), 801-1 Mukoyama, Naka-machi, Ibaraki-ken, 311-0193 (Japan)

    2005-01-01

    Recent activities on the research and development of 170 GHz gyrotron were presented. In the 170 GHz gyrotron experiment in JAERI, pulse duration had been limited by the beam current decrease due to the emission cooling of the electron emitter. A preprogramming control of the heater power was introduced to keep the beam current constant and to avoid the oscillation mode shift to a lower mode during the operation. And, a built-in mode converter system was improved to reduce the stray radiation. In the preliminary experiment results of 0.2 MW/480 sec and 0.13 MW/600 sec were obtained. The pulse extension experiment at higher power will be followed. In parallel, a study of the high order mode oscillation was carried out using a short pulse gyrotron ({approx}1 msec). The oscillation mode is TE{sub 31,12}, which allows 1.5 MW level CW operation. A stable oscillation of TE{sub 31,12} was demonstrated at the power of 1.56 MW. The maximum efficiency was 30% at 1 MW output. This result indicates that the high order mode up to the level of TE{sub 31,12} will be acceptable to increase the power or to reduce the heat load on the cavity wall at 1 MW output.

  4. 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.

  5. 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...

  6. Nonlinear oscillations of TM-mode gyrotrons

    Science.gov (United States)

    Chang, Tsun-Hsu; Yao, Hsin-Yu; Su, Bo-Yuan; Huang, Wei-Chen; Wei, Bo-Yuan

    2017-12-01

    This study investigates the interaction between the relativistic electrons and the waves in cavities with fixed field profiles. Both the transverse electric (TE) and the transverse magnetic (TM) cavity modes are examined, including three first-axial modes, TE011, TM011, and TM111, and two zero-axial modes, TM010 and TM110. The first-axial modes have the same resonant frequency, so a direct comparison can be made. By sweeping the electron pitch factor (α) and the electron transit angle (Θ), the optimal converting efficiency of TM modes occurs at α = 1.5 and Θ = 1.5π, unlike the TE mode of α = 2.0 and Θ = 1.0π. The converting efficiencies of both the first-axial TM modes are much lower than that of TE011 mode. The starting currents of TM011 and TM111 modes are four times higher than that of TE011 mode, indicating that these two TM modes are very difficult to oscillate. This evidences that under the traditional operating conditions, the TM-mode gyrotrons are insignificant. However, the two unique, zero-axial TM modes have relatively high converting efficiency. The highest converting efficiency of TM110 is 27.4%, the same value as that of TE011 mode. The starting currents of TM110 mode and TE011 mode are at the same level. The results suggest that some TM-mode gyrotron oscillators are feasible and deserve further theoretical and experimental studies.

  7. Systematic Observation of Time-Dependent Phenomena in the RF Output Spectrum of High Power Gyrotrons

    Directory of Open Access Journals (Sweden)

    Kern Stefan

    2012-09-01

    Full Text Available At IHM/KIT, high power gyrotrons with conventional cavity (e.g. 1 MW CW at 140 GHz for the stellarator Wendelstein 7-X and coaxial cavity (2 MW shortpulse at 170 GHz for ITER for fusion applications are being developed and verified experimentally. Especially with respect to the problem of parasitic RF oscillations in the beam tunnel of some W7-X tubes, investigations of the gyrotron RF output spectrum have proved to be a valuable source of diagnostic information. Signs of transient effects in millisecond pulses, like frequency switching or intermittent low-frequency modulation, have indicated that truly time-dependent measurements with high frequency resolution and dynamic range could give deeper insight into these phenomena. In this paper, an improved measurement system is presented, which employs a fast oscilloscope as receiver. Shorttime Fourier transform (STFT is applied to the time-domain signal, yielding time-variant spectra with frequency resolutions only limited by acquisition length and STFT segmentation choice. Typical reasonable resolutions are in the range of 100 kHz to 10 MHz with a currently memory-limited maximum acquisition length of 4 ms. A key feature of the system consists in the unambiguity of frequency measurement: The system receives through two parallel channels, each using a harmonic mixer (h = 9 – 12 to convert the signal from RF millimeter wave frequencies (full D-Band, 110 – 170 GHz to IF (0 – 3 GHz. For each IF output signal of each individual mixer, injection side and receiving harmonic are initially not known. Using accordingly determined LO frequencies, this information is retrieved from the redundancy of the channels, yielding unambiguously reconstructed RF spectra with a total span of twice the usable receiver IF bandwidth, up to ≈ 6 GHz in our case. Using the system, which is still being improved continuously, various transient effects like cavity mode switching, parasitic oscillation frequency variation

  8. 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.

  9. Feasibility study of a cryogenically cooled window for high-power gyrotrons

    Energy Technology Data Exchange (ETDEWEB)

    Haste, G.R.; Kimrey, H.D.; Prosise, J.D.

    1986-07-01

    Single-crystal sapphire is currently in use as the material for output windows in high-power microwave tubes, particularly gyrotrons. These windows are currently being cooled by fluorocarbon fluids at near-room temperatures. There are, however, several advantages in operating the window at very low temperatures: less absorption and consequent heating of the window, greater material strength, improved resistance to crack formation, greater thermal conductivity, and reduced thermal expansion. Operation at cryogenic temperatures is shown to be feasible. The output power, which is currently limited by window constraints, could be increased by an order of magnitude or more.

  10. Experimental Study Of A 1.5-mw, 110-ghz Gyrotron Oscillator

    CERN Document Server

    Anderson, J P

    2005-01-01

    This thesis reports the design, construction and testing of a 1.5 MW, 110 GHz gyrotron oscillator. This high power microwave tube has been proposed as the next evolutionary step for gyrotrons used to provide electron cyclotron heating required in fusion devices. A short pulse gyrotron based on the industrial tube design was built at MIT for experimental studies. The experiments are the first demonstration of such high powers at 110 GHz. Using a 96 kV, 40 A electron beam, over 1.4 MW was axially extracted in the design (TE22,6) mode in 3 μs pulses, corresponding to a microwave efficiency of 37%. The beam alpha, the ratio of transverse to axial velocity in the electron beam, was measured with a probe. At the high efficiency operating point the beam alpha was measured as 1.33. This value of alpha is less than the design value of 1.4, possibly accounting for the slightly reduced experimental efficiency. The output power and efficiency, as a function of magnetic field, beam voltage, and beam current, are in...

  11. Design, simulation, and experimental results of a 110 GHz high-power gyrotron mode converter

    Energy Technology Data Exchange (ETDEWEB)

    Denison, D.R.; Blank, M.; Chu, T.S.; Hogge, J.P.; Kreischer, K.E.; Temkin, R.J. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center; Harper, B.; Lorbeck, J.A.; Vernon, R.J. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center]|[Univ. of Wisconsin, Madison, WI (United States)

    1996-12-31

    The authors present the design, computer simulation, and experimental results of a quasi-optical mode converter for use in a 110 GHz high-power gyrotron. The particular gyrotron under test generates a right-handed TE{sub 22.6} circular waveguide mode, and is designed to produce megawatt power levels over pulse durations on the order of 5s. This high power level provides a rigorous constraint on the output-beam shape; namely, that the peaking factor be approximately 2.0. Such a peaking factor corresponds to a nearly flat power distribution across the output window to allow for proper cooling of the window. To that end, the mode converter employs a rippled-wall waveguide mode transformer/beam launcher, and a pair of toroidal focusing mirrors to produce a Gaussian-like beam. Two shaping mirrors follow, and convert the Gaussian beam into a quasi-optical beam with a flat power distribution. The rippled-wall launcher was designed using standard coupled mode theory, and the toroidal mirrors derive from Gaussian beam analysis. The shaping mirrors result from a vector diffraction synthesis procedure developed at UW.

  12. High current multicharged metal ion source using high power gyrotron heating of vacuum arc plasma.

    Science.gov (United States)

    Vodopyanov, A V; Golubev, S V; Khizhnyak, V I; Mansfeld, D A; Nikolaev, A G; Oks, E M; Savkin, K P; Vizir, A V; Yushkov, G Yu

    2008-02-01

    A high current, multi charged, metal ion source using electron heating of vacuum arc plasma by high power gyrotron radiation has been developed. The plasma is confined in a simple mirror trap with peak magnetic field in the plug up to 2.5 T, mirror ratio of 3-5, and length variable from 15 to 20 cm. Plasma formed by a cathodic vacuum arc is injected into the trap either (i) axially using a compact vacuum arc plasma gun located on axis outside the mirror trap region or (ii) radially using four plasma guns surrounding the trap at midplane. Microwave heating of the mirror-confined, vacuum arc plasma is accomplished by gyrotron microwave radiation of frequency 75 GHz, power up to 200 kW, and pulse duration up to 150 micros, leading to additional stripping of metal ions by electron impact. Pulsed beams of platinum ions with charge state up to 10+, a mean charge state over 6+, and total (all charge states) beam current of a few hundred milliamperes have been formed.

  13. The Designs of High Efficiency Launcher of Quasi-Optical Mode Converter for High Power Gyrotrons

    Science.gov (United States)

    Minami, R.; Kasugai, A.; Takahashi, K.; Kobayashi, N.; Mitsunaka, Y.; Sakamoto, K.

    2006-01-01

    A high efficiency launcher of quasi-optical (QO) mode converters for high power gyrotrons have been designed and tested. A helical cut launcher radiates the RF power via its straight cut onto the first phase correcting mirror. The launchers have been optimized for the TE31.8 mode at 170 GHz and TE22.6 mode at 110 GHz by numerically optimizing a launcher surface. The helical cut of the launcher has been optimized by taking the taper angle into account. Further more, the amplitude of the surface perturbation have been optimized for improved focusing in order to reduce the diffraction losses at the helical cut. Low power measurement shows a good agreement with the design. High efficiency characteristics of the design have also been calculated on the assumption of frequency downshift due to the thermal expansion of the cavity and stepwise frequency tuning by changing the operating mode. Besides, the possibility of high efficiency launcher for higher mode is discussed, and these results give the prospect to high efficiency long pulse gyrotrons.

  14. Recent achievements on tests of series gyrotrons for W7-X and planned extension at the KIT gyrotron test facility

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, M., E-mail: martin.schmid@kit.edu [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Choudhury, A. Roy; Dammertz, G. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Erckmann, V. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Max-Planck-Institute for Plasmaphysics, Association EURATOM-IPP, Greifswald (Germany); Gantenbein, G.; Illy, S. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Jelonnek, J. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Institute of High Frequency Techniques and Electronics (IHE) (Germany); Kern, S. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Legrand, F. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Thales Electron Devices, Vélicy (France); Rzesnicki, T.; Samartsev, A. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Schlaich, A.; Thumm, M. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Institute of High Frequency Techniques and Electronics (IHE) (Germany)

    2013-10-15

    Highlights: ► Solution found to suppress parasitic beam tunnel oscillations on high power gyrotrons. ► Electron beam sweeping technique to avoid plastic deformation on collector of high power gyrotrons. ► Ongoing investigations on limitations of gyrotron efficiency. ► Upgrade of 10 MW CW modulator for gyrotrons with multistage depressed collectors. -- Abstract: Parasitic beam tunnel oscillations have been hampering the series production of gyrotrons for W7-X. This problem has now been overcome thanks to the introduction of a specially corrugated beam tunnel. Two gyrotrons equipped with the new beam tunnel have fully passed the acceptance tests. Despite excellent power capability, the expected efficiency has not yet been achieved, possibly due to the presence of parasitic oscillations suspected to be dynamic after-cavity-oscillations (ACI's) or due to insufficient electron beam quality. Both theoretical and experimental investigations on these topics are ongoing. On previous W7-X gyrotrons collector fatigue has been observed, not (yet) leading to any failures so far. The plastic deformation occurring on the collector has now been eliminated due to the strict use (on all gyrotrons) of a sweeping method which combines the conventional 7 Hz solenoid sweeping technique with a 50 Hz transverse-field sweep system. Starting in 2013, the gyrotron test facility at KIT will be enhanced, chiefly with a new 10 MW DC modulator, capable of testing gyrotrons up to 4 MW CW output power with multi-stage-depressed collectors.

  15. Design and operation of 140 GHz gyrotron oscillators for power levels up to 1 MW CW

    Energy Technology Data Exchange (ETDEWEB)

    Jory, H.; Bier, R.; Craig, L.J.; Felch, K.; Ives, L.; Lopez, N.; Spang, S.

    1986-12-01

    Varian has designed and tested 140 GHz gyrotron oscillators that have generated output powers of 100 kW CW and 200 kW for 1 ms pulses. Upcoming tubes will be designed to operate at power levels of 200 kW CW and ultimately up to 1 MW CW. The important design considerations which are addressed in the higher power tubes include the design of the electron gun, interaction circuit, and output window. These issues will be discussed and the results of the earlier 140 GHz gyrotron work at Varian will be summarized.

  16. 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...

  17. Efficient Low-Voltage Operation of a CW Gyrotron Oscillator at 233 GHz.

    Science.gov (United States)

    Hornstein, Melissa K; Bajaj, Vikram S; Griffin, Robert G; Temkin, Richard J

    2007-02-01

    The gyrotron oscillator is a source of high average power millimeter-wave through terahertz radiation. In this paper, we report low beam power and high-efficiency operation of a tunable gyrotron oscillator at 233 GHz. The low-voltage operating mode provides a path to further miniaturization of the gyrotron through reduction in the size of the electron gun, power supply, collector, and cooling system, which will benefit industrial and scientific applications requiring portability. Detailed studies of low-voltage operation in the TE(2) (,) (3) (,) (1) mode reveal that the mode can be excited with less than 7 W of beam power at 3.5 kV. During CW operation with 3.5-kV beam voltage and 50-mA beam current, the gyrotron generates 12 W of RF power at 233.2 GHz. The EGUN electron optics code describes the low-voltage operation of the electron gun. Using gun-operating parameters derived from EGUN simulations, we show that a linear theory adequately predicts the low experimental starting currents.

  18. 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.

  19. Research of the Electron Cyclotron Emission with Vortex Property excited by high power high frequency Gyrotron

    Science.gov (United States)

    Goto, Yuki; Kubo, Shin; Tsujimura, Tohru; Takubo, Hidenori

    2017-10-01

    Recently, it has been shown that the radiation from a single electron in cyclotron motion has vortex property. Although the cyclotron emission exists universally in nature, the vortex property has not been featured because this property is normally cancelled out due to the randomness in gyro-phase of electrons and the development of detection of the vortex property has not been well motivated. In this research, we are developing a method to generate the vortex radiation from electrons in cyclotron motion with controlled gyro-phase. Electron that rotates around the uniform static magnetic field is accelerated by right-hand circular polarized (RHCP) radiation resonantly when the cyclotron frequency coincides with the applied RHCP radiation frequency. A large number of electrons can be coherently accelerated in gyro-phase by a RHCP high power radiation so that these electrons can radiate coherent emission with vortex feature. We will show that vortex radiation created by purely rotating electrons for the first time.

  20. Development of new generation software tools for simulation of electron beam formation in novel high power gyrotrons

    Energy Technology Data Exchange (ETDEWEB)

    Sabchevski, S [Institute of Electronics, Bulgarian Academy of Sciences, BG-1784 Sofia (Bulgaria); Zhelyazkov, I [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria); Benova, E [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria); Atanassov, V [Institute of Electronics, Bulgarian Academy of Sciences, BG-1784 Sofia (Bulgaria); Dankov, P [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria); Thumm, M [Forschungszentrum Karlsruhe, Association EURATOM-FZK, Institute for Pulsed Power and Microwave Technology, D-76021 Karlsruhe (Germany); Dammertz, G [University of Karlsruhe, Institute of High Frequency Techniques and Electronics, D-76128 Karlsruhe (Germany); Piosczyk, B [Forschungszentrum Karlsruhe, Association EURATOM-FZK, Institute for Pulsed Power and Microwave Technology, D-76021 Karlsruhe (Germany); Illy, S [Forschungszentrum Karlsruhe, Association EURATOM-FZK, Institute for Pulsed Power and Microwave Technology, D-76021 Karlsruhe (Germany); Tran, M Q [Centre de Recherches en Physique des Plasmas, Association EURATOM-CRPP, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Alberti, S [Centre de Recherches en Physique des Plasmas, Association EURATOM-CRPP, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Hogge, J-Ph [Centre de Recherches en Physique des Plasmas, Association EURATOM-CRPP, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)

    2006-07-15

    Computer aided design (CAD) based on numerical experiments performed by using adequate physical models and efficient simulation codes is an indispensable tool for development, investigation, and optimization of gyrotrons used as radiation sources for electron cyclotron resonance heating (ECRH) of fusion plasmas. In this paper, we review briefly the state-of-the-art in the field of modelling and simulation of intense, relativistic, helical electron beams formed in the electron-optical systems (EOS) of powerful gyrotrons. We discuss both the limitations of the known computer codes and the requirements for increasing their capabilities for solution of various design problems that are being envisaged in the development of the next generation gyrotrons for ECRH. Moreover, we present the concept followed by us in an attempt to unite the advantages of the modern programming techniques with self-consistent, first-principles 3D physical models in the creation of a new highly efficient and versatile software package for simulation of powerful gyrotrons.

  1. Quasi-optical converters for high-power gyrotrons: a brief review of physical models, numerical methods and computer codes

    Energy Technology Data Exchange (ETDEWEB)

    Sabchevski, S [Institute of Electronics, Bulgarian Academy of Sciences, BG-1784 Sofia (Bulgaria); Zhelyazkov, I [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria); Benova, E [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria); Atanassov, V [Institute of Electronics, Bulgarian Academy of Sciences, BG-1784 Sofia (Bulgaria); Dankov, P [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria); Thumm, M [Forschungszentrum Karlsruhe, Association EURATOM-FZK, Institute for Pulsed Power and Microwave Technology, D-76021 Karlsruhe (Germany); Arnold, A [University of Karlsruhe, Institute of High Frequency Techniques and Electronics, D-76128 Karlsruhe (Germany); Jin, J [Forschungszentrum Karlsruhe, Association EURATOM-FZK, Institute for Pulsed Power and Microwave Technology, D-76021 Karlsruhe (Germany); Rzesnicki, T [Forschungszentrum Karlsruhe, Association EURATOM-FZK, Institute for Pulsed Power and Microwave Technology, D-76021 Karlsruhe (Germany)

    2006-07-15

    Quasi-optical (QO) mode converters are used to transform electromagnetic waves of complex structure and polarization generated in gyrotron cavities into a linearly polarized, Gaussian-like beam suitable for transmission. The efficiency of this conversion as well as the maintenance of low level of diffraction losses are crucial for the implementation of powerful gyrotrons as radiation sources for electron-cyclotron-resonance heating of fusion plasmas. The use of adequate physical models, efficient numerical schemes and up-to-date computer codes may provide the high accuracy necessary for the design and analysis of these devices. In this review, we briefly sketch the most commonly used QO converters, the mathematical base they have been treated on and the basic features of the numerical schemes used. Further on, we discuss the applicability of several commercially available and free software packages, their advantages and drawbacks, for solving QO related problems.

  2. 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.

  3. Recent result of gyrotron operation in NIFS

    Directory of Open Access Journals (Sweden)

    Ito Satoshi

    2015-01-01

    Full Text Available In the last Large Helical Device (LHD experimental campaign, a 154GHz gyrotron which had been conditioned to generate 1 MW/2 s, 0.5 MW/CW was installed for LHD experiments. Four high power gyrotrons (three-77 GHz/1~1.5 MW and one-154 GHz/1 MW and a CW gyrotron (84 GHz/0.2 MW are ready. Our experiment requires high energy and various injection patterns for Electron Cyclotron Resonance Heating (ECRH. Higher individual injection power and various injection patterns, we developed a power enhancement method by stepped anode acceleration voltage control and operated the gyrotron in the hard excitation region. These operations were realized by a remote controlled waveform generator. However the oscillation map of high power or long pulse operation in the hard excitation region were limited because in order to achieve the hard excitation region by the anode voltage control one must pass through the high anode current phase within a time short enough that the anode or the anode power supply is not overloaded. This limitation becomes more critical when the gyrotron beam current is increased in order to increase the output power. In the long pulse operation it was impossible to reach the hard excitation region in a low beam current (<10A.

  4. X-Ray Detected Magnetic Resonance at Sub-THz Frequencies Using a High Power Gyrotron Source

    Science.gov (United States)

    Rogalev, Andrei; Goulon, José; Goujon, Gérard; Wilhelm, Fabrice; Ogawa, Isamu; Idehara, Toshitaka

    2012-07-01

    X-ray Detected Magnetic Resonance (XDMR) is a novel spectroscopy which makes use of X-ray Magnetic Circular Dichroism (XMCD) to probe the resonant precession of local magnetization components in a strong microwave pump field. In Sections 1 and 2, we briefly review the conceptual bases of XDMR and the potential interest of increasing the pumping frequency up to the THz frequency range. In Sections 3-5, we discuss the feasibility of such challenging experiments. Starting from a comparison of experiments carried out either in the transverse (TRD) or longitudinal (LOD) detection geometries, we show that XDMR measurements at sub-THz frequencies require a substantial increase in pumping power: this is where a gyrotron source looks most appropriate. It is the aim of this paper to discuss how to conduct such experiments, emphasis being laid on feasibility tests recently carried out at the ESRF using a refurbished version of Gyrotron FU-II built at the FIR-FU. In this context, we propose a new detection scheme of sub-THz XDMR spectra based on the concept of frequency-mixing in LOD geometry.

  5. Design of High Power FELS and the Effects of Diffraction on Detuning in an FEL Oscillator

    Science.gov (United States)

    2015-12-01

    a 2D representation of the optical wavefront at the left and right mirrors with the peak value indicated in the top right. 18 *** FEL OSCILLATOR 4D...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS DESIGN OF HIGH POWER FELS AND THE EFFECTS OF DIFFRACTION ON DETUNING IN AN FEL OSCILLATOR by...to 12-18-2015 4. TITLE AND SUBTITLE DESIGN OF HIGH POWER FELS AND THE EFFECTS OF DIFFRACTION ON DE- TUNING IN AN FEL OSCILLATOR 5. FUNDING NUMBERS 6

  6. Cutting-Edge High-Power Ultrafast Thin Disk Oscillators

    Directory of Open Access Journals (Sweden)

    Thomas Südmeyer

    2013-04-01

    Full Text Available A growing number of applications in science and industry are currently pushing the development of ultrafast laser technologies that enable high average powers. SESAM modelocked thin disk lasers (TDLs currently achieve higher pulse energies and average powers than any other ultrafast oscillator technology, making them excellent candidates in this goal. Recently, 275 W of average power with a pulse duration of 583 fs were demonstrated, which represents the highest average power so far demonstrated from an ultrafast oscillator. In terms of pulse energy, TDLs reach more than 40 μJ pulses directly from the oscillator. In addition, another major milestone was recently achieved, with the demonstration of a TDL with nearly bandwidth-limited 96-fs long pulses. The progress achieved in terms of pulse duration of such sources enabled the first measurement of the carrier-envelope offset frequency of a modelocked TDL, which is the first key step towards full stabilization of such a source. We will present the key elements that enabled these latest results, as well as an outlook towards the next scaling steps in average power, pulse energy and pulse duration of such sources. These cutting-edge sources will enable exciting new applications, and open the door to further extending the current performance milestones.

  7. High power singlemode edge-emitting master oscillator power amplifier

    Science.gov (United States)

    O'Brien, S.; Parke, R.; Welch, D. F.; Mehuys, D.; Scifres, D.

    1992-01-01

    An edge-emitting monolithically integrated master oscillator power amplifier (M-MOPA) has been fabricated by integrating a distributed Bragg reflector laser with a 500 microns long single mode amplifier. The M-MOPA contains a strained InGaAs quantum well in the active region and operates at about 981.5 nm in an edge-emitting fashion with maximum powers in excess of 175 mW. Single longitudinal and transverse mode operation is maintained to powers in excess of 110 mW CW.

  8. An X-band, high power dielectric resonator oscillator for future military systems.

    Science.gov (United States)

    Mizan, M A; Sturzebecher, D; Higgins, T; Paolella, A

    1993-01-01

    A 9.0-GHz dielectric resonator oscillator (DRO), generating a CW output power of 2.5 W at room temperature, has been designed and fabricated using a high-power GaAs MESFET and a dielectric resonator (DR) in a parallel feedback configuration. The oscillator exhibited a frequency stability of better than 130 ppm, without any temperature compensation, over the range -50 degrees C to +50 degrees C. The output power varied from +35 dBm (3.2 W) at -50 degrees C to +33 dBm (2 W) at +50 degrees C. The single-sideband phase noise levels were measured and found to be -105 and -135 dBc/Hz, at 10- and 100-kHz carrier offset frequencies, respectively. The oscillator output was then fed into a single-stage high-power MESFET amplifier, resulting in a total RF power output of 6.5 W. The overall DC to RF conversion efficiency of the 6.5-W unit was approximately 15.3%

  9. State-of-the-art of high power gyro-devices and free electron masers. Update 2015

    Energy Technology Data Exchange (ETDEWEB)

    Thumm, Manfred [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany). Inst. fuer Hochleistungsimpuls- und Mikrowellentechnik, Programm Fusion

    2016-07-01

    Gyrotron oscillators (gyromonotrons) are mainly used as high power millimeter wave sources for electron cyclotron resonance heating (ECRH), electron cyclotron current drive (ECCD), stability control and diagnostics of magnetically confined plasmas for generation of energy by controlled thermonuclear fusion. The maximum pulse length of commercially available 140 GHz, megawatt- class gyrotrons employing synthetic diamond output windows is 30 minutes (CPI and European KIT-CRPP-TED collaboration). The world record parameters of the European megawatt-class 140 GHz gyrotron are: 0.92 MW output power at 30 min. pulse duration, 97.5% Gaussian mode purity and 44% efficiency, employing a single-stage depressed collector (SDC) for energy recovery. A maximum output power of 1.5 MW in 4.0 s pulses at 45% efficiency was generated with the JAEA-TOSHIBA 110 GHz gyrotron. The Japan 170 GHz ITER gyrotron achieved 1 MW, 800 s at 55% efficiency and holds the energy world record of 2.88 GJ (0.8 MW, 60 min.) and the efficiency record of 57% for tubes with an output power of more than 0.5 MW. The Russian 170 GHz ITER gyrotron achieved 0.99 (1.2) MW with a pulse duration of 1000 (100) s and 53 (53) % efficiency. The prototype tube of the European 2 MW, 170 GHz coaxial-cavity gyrotron achieved in short pulses the record power of 2.1 MW at 46% efficiency and 96% Gaussian mode purity. Gyrotrons with pulsed magnet for various short-pulse applications deliver P{sub out}=210 kW with τ=20 μs at frequencies up to 670 GHz (η≅20%), P{sub out}=5.3 kW at 1 THz (η=6.1%), and P{sub out}=0.5 kW at 1.3 THz (η=0.6%). Gyrotron oscillators have also been successfully used in materials processing. Such technological applications require gyrotrons with the following parameters: f ≥ 24 GHz, P{sub out}=4-50 kW, CW, η≥30%. This paper gives an update of the experimental achievements related to the development of high power gyrotron oscillators for long-pulse or CW operation and pulsed gyrotrons for

  10. Combined wide pump tuning and high power of a continuous-wave, singly resonant optical parametric oscillator

    NARCIS (Netherlands)

    Herpen, M.M.J.W. van; Bisson, S.E.; Ngai, A.K.Y.; Harren, F.J.M.

    2004-01-01

    A new singly resonant, single-frequency optical parametric oscillator (OPO) has been developed for the 2.6-4.7 mum infrared wavelength region, using a high power (>20 W), widely tunable (1024-1034 nm) Yb:YAG pump source. With the OPO frequency stabilized with an intracavity etalon, the OPO achieved

  11. High power master oscillator power amplifier (MOPA) AlGaAs laser for intersatellite communications

    Science.gov (United States)

    Cornwell, Donald M., Jr.

    1992-01-01

    A master oscillator power amplifier (MOPA) configuration has been developed using an anti-reflection-coated AlGaAs semiconductor broad area laser in a reflective amplifier mode. For CW injection, the MOPA produced 340 mW of diffraction-limited power. The semiconductor MOPA configuration also produced peak diffraction-limited powers of 360 mW and 320 mW for quaternary pulse position Q-PPM modulation rates of 50 Mbps and 325 Mbps, respectively, for a peak injected power of 100 mW. Angular beamsteering during modulation was minimized by collimating the injected beam. The diffraction-limited peak power was limited by the frequency chirp of the master oscillator and also by the coupling losses of the injected beam.

  12. High-power arrays of quantum cascade laser master-oscillator power-amplifiers.

    Science.gov (United States)

    Rauter, Patrick; Menzel, Stefan; Goyal, Anish K; Wang, Christine A; Sanchez, Antonio; Turner, George; Capasso, Federico

    2013-02-25

    We report on multi-wavelength arrays of master-oscillator power-amplifier quantum cascade lasers operating at wavelengths between 9.2 and 9.8 μm. All elements of the high-performance array feature longitudinal (spectral) as well as transverse single-mode emission at peak powers between 2.7 and 10 W at room temperature. The performance of two arrays that are based on different seed-section designs is thoroughly studied and compared. High output power and excellent beam quality render the arrays highly suitable for stand-off spectroscopy applications.

  13. Operation experiences of the super conducting magnet for a gyrotron of the JT-60U ECH system

    Energy Technology Data Exchange (ETDEWEB)

    Igarashi, Koichi; Seki, Masami; Shimono, Mitsugu; Terakado, Masayuki; Ishii, Kazuhiro; Takahashi, Masami [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2003-03-01

    The JT-60U electron cyclotron heating (ECH) system can heat plasmas locally and drive a plasma current with four 1 MW-5 sec gyrotrons. The super conducting magnets (SCM) are required for oscillation of the gyrotron at a working frequency of 110 GHz. The SCM provides a high magnetic field of 4.5T at the cavity inside the gyrotron. This SCM system is characterized by 1) operation without liquid Helium owing to a 4K-refrigerator applied to the magnetic coils, 2) easy maintenance. Operational experiences about the SCM system through a long term experiment for a high power gyrotron are very valuable. According to those operational experiences, it is clarified the 4K-refrigerator should be renewed in order to keep low temperature of the SCM. It is also found that 200 hours or less are required for the super conducting condition (<5K) after long stopping time of the refrigerator up to 150 hours. This is useful information for making a plan about ECH experiments. (author)

  14. Fine structure of high-power microwave-induced resistance oscillations

    Science.gov (United States)

    Shi, Qianhui; Zudov, Michael; Dmitriev, Ivan; Baldwin, Kirk; Pfeiffer, Loren; West, Ken; Smet, Jurgen

    We report on a pronounced fine structure of microwave-induced resistance oscillations (MIRO) in an ultra-clean two-dimensional electron gas. This fine structure is manifested by additional sharp extrema residing beside the primary ones and, according to theoretical considerations, originates from multiphoton-assisted scattering off short-range impurities. Unique properties of the fine structure allow us to access all experimental parameters, including microwave power, and to separate different contributions to photoresistance. Finally, we demonstrate that the fine structure can be used to quantitatively assess the correlation properties of the disorder potential. The work at the University of Minnesota was funded by the NSF Grant No. DMR-1309578. The work at Princeton University was funded by the Gordon and Betty Moore Foundation through the EPiQS initiative Grant GBMF4420, and by the NSF MRSEC Grant DMR-1420541.

  15. Recent Trends in Fusion Gyrotron Development at KIT

    Directory of Open Access Journals (Sweden)

    Gantenbein G.

    2017-01-01

    Full Text Available ECRH&CD is one of the favorite heating system for magnetically confined nuclear fusion plasmas. KIT is strongly involved in the development of high power gyrotrons for use in ECRH systems for nuclear fusion. KIT is upgrading the sub-components of the existing 2 MW, 170 GHz coaxial-cavity short-pulse gyrotron to support long-pulse operation up to 1 s, all components will be equipped with a specific active cooling system. Two important developments for future high power, highly efficient gyrotrons will be discussed: design of gyrotrons with high operating frequency (∼ 240 GHz and efficiency enhancement by using advanced collector designs with multi-staged voltage depression.

  16. Recent Trends in Fusion Gyrotron Development at KIT

    Science.gov (United States)

    Gantenbein, G.; Avramidis, K.; Franck, J.; Illy, S.; Ioannidis, Z. C.; Jin, J.; Jelonnek, J.; Kalaria, P.; Pagonakis, I. Gr.; Ruess, S.; Rzesnicki, T.; Thumm, M.; Wu, C.

    2017-10-01

    ECRH&CD is one of the favorite heating system for magnetically confined nuclear fusion plasmas. KIT is strongly involved in the development of high power gyrotrons for use in ECRH systems for nuclear fusion. KIT is upgrading the sub-components of the existing 2 MW, 170 GHz coaxial-cavity short-pulse gyrotron to support long-pulse operation up to 1 s, all components will be equipped with a specific active cooling system. Two important developments for future high power, highly efficient gyrotrons will be discussed: design of gyrotrons with high operating frequency (˜ 240 GHz) and efficiency enhancement by using advanced collector designs with multi-staged voltage depression.

  17. High-power, continuous-wave, mid-infrared optical parametric oscillator based on MgO:sPPLT.

    Science.gov (United States)

    Chaitanya Kumar, S; Ebrahim-Zadeh, M

    2011-07-01

    We report a stable, high-power, cw, mid-IR optical parametric oscillator using MgO-doped stoichiometric periodically poled LiTaO₃ (MgO:sPPLT) pumped by a Yb fiber laser at 1064 nm. The singly resonant oscillator (SRO), based on a 30 mm long crystal, is tunable over 430 nm from 3032 to 3462 nm and can generate as much as 5.5 W of mid-IR output power, with >4 W of over 60% of the tuning range and under reduced thermal effects, enabling room temperature operation. Idler power scaling measurements at ~3.3 μm are compared with an MgO-doped periodically poled LiNbO₃ cw SRO, confirming that MgO:sPPLT is an attractive material for multiwatt mid-IR generation. The idler output at 3299 nm exhibits a peak-to-peak power stability better than 12.8% over 5 h and frequency stability of ~1 GHz, while operating close to room temperature, and has a linewidth of ~0.2 nm, limited by the resolution of the wavemeter. The corresponding signal linewidth at 1570 nm is ~21 MHz.

  18. High power, widely tunable dual-wavelength 2 μm laser based on intracavity KTP optical parametric oscillator

    Science.gov (United States)

    Yan, Dexian; Wang, Yuye; Xu, Degang; Shi, Wei; Zhong, Kai; Liu, Pengxiang; Yan, Chao; Mei, Jialin; Shi, Jia; Yao, Jianquan

    2017-01-01

    We presented a high power, widely tunable narrowband 2 μm dual-wavelength source employing intracavity optical parametric oscillator with potassium titanium oxide phosphate (KTP) crystal. Two identical KTP crystals were oriented oppositely in the OPO cavity to compensate the walk-off effect. The output average power of dual-wavelength 2 μm laser was up to 18.18 W at 10 kHz with the peak power of 165 kW. The two wavelengths can be tuned in the range of 2070.7 nm to 2191.1 nm for ordinary light while in the range of 2190.7 nm to 2065.9 nm for extraordinary light with the full width at half maximum (FWHM) about 0.8 nm. The pulse width of the tunable laser was as narrow as 11 ns. The beam quality factor M 2 was less than 4 during wavelength tuning.

  19. TWANG-PIC, a novel gyro-averaged one-dimensional particle-in-cell code for interpretation of gyrotron experiments

    Energy Technology Data Exchange (ETDEWEB)

    Braunmueller, F., E-mail: falk.braunmueller@epfl.ch; Tran, T. M.; Alberti, S.; Genoud, J.; Hogge, J.-Ph.; Tran, M. Q. [École Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne (Switzerland); Vuillemin, Q. [Institut de Physique Nucléaire (IPN), F-91406 Orsay (France)

    2015-06-15

    A new gyrotron simulation code for simulating the beam-wave interaction using a monomode time-dependent self-consistent model is presented. The new code TWANG-PIC is derived from the trajectory-based code TWANG by describing the electron motion in a gyro-averaged one-dimensional Particle-In-Cell (PIC) approach. In comparison to common PIC-codes, it is distinguished by its computation speed, which makes its use in parameter scans and in experiment interpretation possible. A benchmark of the new code is presented as well as a comparative study between the two codes. This study shows that the inclusion of a time-dependence in the electron equations, as it is the case in the PIC-approach, is mandatory for simulating any kind of non-stationary oscillations in gyrotrons. Finally, the new code is compared with experimental results and some implications of the violated model assumptions in the TWANG code are disclosed for a gyrotron experiment in which non-stationary regimes have been observed and for a critical case that is of interest in high power gyrotron development.

  20. Multimode time-dependent gyrotron equations for different time scales

    Science.gov (United States)

    Dumbrajs, O.; Kalis, H.

    2017-09-01

    Development of gyrotrons requires careful understanding of different regimes of gyrotron oscillations. For a long time, the gyrotron theory was developed assuming that the transit time of electrons through the interaction space is much shorter than the cavity fill time. Correspondingly, it was assumed that during this transit time, the amplitude of microwave oscillations remains constant. However, there are situations when this assumption is not fulfilled, or is marginally fulfilled. In such cases, a different mathematical formalism has to be used. The present paper generalizes the new formalism to the multi mode case. The particular example considered indicates that in some cases the results obtained by means of the old and the new formalism differ significantly.

  1. Soviet Development of Gyrotrons

    Science.gov (United States)

    1986-05-01

    Relationship Type of Device Remarks V, - Vc, anomalous Doppler Capable of 100 percent efficiency, CRM but more cumbersome than Cheren- kov devices V...authors; and discusses inlividual Soviet reseaLc- groups, the basic organizational units responAiLle for the CRM and gyrotron research and development. The...maintained a cCnEistEnt iecord of significant achievements; it has managed to overcome the systenic yeaxness of the Soviet R&C systeg in teimg atle to

  2. High-power 200 fs Kerr-lens mode-locked Yb:YAG thin-disk oscillator.

    Science.gov (United States)

    Pronin, O; Brons, J; Grasse, C; Pervak, V; Boehm, G; Amann, M-C; Kalashnikov, V L; Apolonski, A; Krausz, F

    2011-12-15

    We demonstrate a power-scalable Kerr-lens mode-locked Yb:YAG thin-disk oscillator. It delivers 200 fs pulses at an average power of 17 W and a repetition rate of 40 MHz. At an increased (180 W) pump power level, the laser produces 270 fs 1.1 μJ pulses at an average power of 45 W (optical-to-optical efficiency of 25%). Semiconductor-saturable-absorber-mirror-assisted Kerr-lens mode locking (KLM) and pure KLM with a hard aperture show similar performance. To our knowledge, these are the shortest pulses achieved from a mode-locked Yb:YAG disk oscillator and this is the first demonstration of a Kerr-lens mode-locked thin-disk laser.

  3. High power all-metal spin torque oscillator using full Heusler Co{sub 2}(Fe,Mn)Si

    Energy Technology Data Exchange (ETDEWEB)

    Seki, Takeshi, E-mail: go-sai@imr.tohoku.ac.jp; Sakuraba, Yuya; Ueda, Masaki; Okura, Ryo; Takanashi, Koki [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Arai, Hiroko; Imamura, Hiroshi [Spintronics Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8568 (Japan)

    2014-09-01

    We showed the high rf power (P{sub out}) emission from an all-metal spin torque oscillator (STO) with a Co{sub 2}Fe{sub 0.4}Mn{sub 0.6}Si (CFMS)/Ag/CFMS giant magnetoresistance (GMR) stack, which was attributable to the large GMR effect thanks to the highly spin-polarized CFMS. The oscillation spectra were measured by varying the magnetic field direction, and the perpendicular magnetic field was effective to increase P{sub out} and the Q factor. We simultaneously achieved a high output efficiency of 0.013%, a high Q of 1124, and large frequency tunability. CFMS-based all-metal STO is promising for overcoming the difficulties that conventional STOs are confronted with.

  4. Development of over-MW gyrotrons for fusion at 14 GHz to sub-THz frequencies

    Science.gov (United States)

    Kariya, T.; Imai, T.; Minami, R.; Sakamoto, K.; Oda, Y.; Ikeda, R.; Shimozuma, T.; Kubo, S.; Idei, H.; Numakura, T.; Tsumura, K.; Ebashi, Y.; Okada, M.; Nakashima, Y.; Yoshimura, Y.; Takahashi, H.; Ito, S.; Hanada, K.; Nagasaki, K.; Ono, M.; Eguchi, T.; Mitsunaka, Y.

    2017-06-01

    Megawatt power gyrotrons are being developed for collaborative electron cyclotron heating (ECH) studies of advanced fusion devices and demonstration power plant (DEMO). (1) In the first experiment of a 300 GHz gyrotron, an output power above 0.5 MW in the TE32,18 single mode was achieved with a pulse width of 2 ms. This was the first observation of MW-scale oscillations in a DEMO-relevant gyrotron mode. It was also found that the reflection at the output window affected the determination of the oscillation mode. Furthermore, several single mode oscillations in the 226-254 GHz range were confirmed, which is important for the step-frequency tunable gyrotron in the sub-THz frequency range. (2) Based on the successful results of the 77 and 154 GHz large helical device (LHD) tubes, a new 154/116 GHz dual-frequency gyrotron with an output of over 1.5 MW is being designed. (3) A new record output of 1.38 MW was obtained using an existing 28 GHz gyrotron. A newly designed tube aimed at achieving a dual-frequency output power of 2 MW at 28 GHz (0.4 MW continuous wave) and 1 MW at 35 GHz was built. In the first experimental test, main mode oscillations were observed at the frequencies of 28.036 and 34.831 GHz with Gaussian-like output beams and output power of 1.27 and 0.48 MW, respectively. A total efficiency of 50% was achieved at 28 GHz operation.

  5. 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

  6. 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

  7. 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.

  8. Development of frequency tunable gyrotrons for plasma diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Idehara, T.; Mitsudo, S.; Sabchevski, S.; Glyavin, M. [Research Center for Development of Far-Infrared Region, Fukui Univ., Fukui (Japan); Ogawa, I. [Faculty of Engineering, Fukui Univ., Fukui (Japan); Sato, M.; Kawahata, K. [National Inst. for Fusion Science, Toki, Gifu (Japan); Brand, G.F. [School of Physics, Univ. of Sydney, NSW (Australia)

    2000-03-01

    Development of two types of frequency tunable gyrotrons are described. One is frequency step-tunable gyrotrons (Gyrotron FU Series) which cover wide range from millimeter to submillimeter wavelength region. The other is a quasi-optical gyrotron operating in 90 and 180 GHz bands. Both are applicable for plasma diagnostics as power sources. (author)

  9. Development of a high-power THz radiation source for plasma diagnostics

    NARCIS (Netherlands)

    Siegrist, M. R.; Bindslev, H.; Brazis, R.; Guyomarc' h, D.; Hogge, J. P.; Moreau, P.; Raguotis, R.

    1999-01-01

    A high power radiation source in the THz range with long pulse and narrow line width is required for diagnosing fusion type plasmas by collective Thomson scattering. Gyrotrons currently meet the requirements concerning power, pulse length and line width when operating in the 50-150 GHz range. They

  10. A novel THz-band double-beam gyrotron for high-field DNP-NMR spectroscopy.

    Science.gov (United States)

    Idehara, Toshitaka; Glyavin, Mikhail; Kuleshov, Alexei; Sabchevski, Svilen; Manuilov, Vladimir; Zaslavsky, Vladislav; Zotova, Irina; Sedov, Anton

    2017-09-01

    We present the first experimental results of the study on a novel second harmonic THz-band double-beam gyrotron. The tube has demonstrated a stable single-mode operation with output parameters that are appropriate for the next-generation 1.2 GHz dynamic nuclear polarization-nuclear magnetic resonance spectroscopy. Besides the design mode (TE8,5), a series of other fundamental and second harmonic modes have been excited. This makes the new gyrotron a versatile radiation source, which can be used also in other applications of the high-power science and technologies.

  11. High-power Kerr-lens mode-locked Yb:YAG thin-disk oscillator in the positive dispersion regime.

    Science.gov (United States)

    Pronin, O; Brons, J; Grasse, C; Pervak, V; Boehm, G; Amann, M-C; Apolonski, A; Kalashnikov, V L; Krausz, F

    2012-09-01

    We demonstrate a self-starting Kerr-lens mode-locked (KLM) Yb:YAG thin-disk oscillator operating in the regime of positive intracavity group-delay dispersion (GDD). It delivers 1.7 ps pulses at an average power of 17 W and a repetition rate of 40 MHz. Dispersive mirrors compress the pulses to a duration of 190 fs (assuming sech2 shape; Fourier limit: 150 fs) at an average power level of 11 W. To our knowledge, this is the first KLM thin-disk oscillator with positive GDD. Output powers of up to 30 W were achieved with an increased output coupler transmission and intracavity GDD. We demonstrate increase of the pulse energy with increasing positive intracavity GDD, limited by difficulties in initiating mode-locking.

  12. The First Decade of the Gyrotronics

    Science.gov (United States)

    Petelin, M. I.

    2017-11-01

    Our review (Nusinovich et al. Journal of Infrared, Millimeter, and Terahertz Waves, 35, 325, 2014) proved to be of interest for gyrotron researchers, gyrotron users, and specialists in neighboring fields of physics but underwent a fair criticism for a number of historical omissions. So my co-authors G. S. Nusinovich and M. K. A. Thumm advised me to supplement our paper (Nusinovich et al. Journal of Infrared, Millimeter, and Terahertz Waves, 35, 325, 2014) with the following memoir.

  13. Millimeter-wave gyrotron traveling-wave tube amplifiers

    CERN Document Server

    Du, Chao-Hai

    2014-01-01

    A gyrotron traveling-wave amplifier (gyro-TWT) with the high-power and broad-band capabilities is considered as a turn-on key for next generation high-resolution radar. The book presents comprehensive theory, methods, and physics related to gyro-TWT. The most challenging problem of instability competition has been for the first time addressed in a focused and systematic way, and reported via concise states and vivid pictures. The book is likely to meet the interest of researchers and engineers in radar and microwave technology, who would like to study the gyro-TWTs and to promote its application in millimeter-wave radars.   Chao-Hai Du is a research professor, and Pu-Kun Liu is a full professor, at Peking University, Beijing, P. R. China.

  14. System using a megawatt class millimeter wave source and a high-power rectenna to beam power to a suspended platform

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, Malcolm; Friedman, Herbert W.

    2005-07-19

    A system for beaming power to a high altitude platform is based upon a high power millimeter gyrotron source, optical transmission components, and a high-power receiving antenna (i.e., a rectenna) capable of rectifying received millimeter energy and converting such energy into useable electrical power.

  15. High-power narrow-linewidth QCW diode-pumped TEM00 1319 nm Nd:YAG oscillator using twisted-mode technique

    Science.gov (United States)

    Bian, Qi; Zhong, Qing-Shuang; Chang, Jin-Quan; Guo, Chuan; Bo, Yong; Zuo, Jun-Wei; Shen, Yu; Zong, Nan; Zhang, Shen-Jin; Yuan, Lei; Cui, Da-Fu; Peng, Qin-Jun; Chen, Hong-Bin; Xu, Zu-Yan

    2017-06-01

    We demonstrated a high-average-power, narrow-linewidth, quasi-continuous-wave diode-side-pumped 1319 nm Nd:YAG twisted-mode laser oscillator with a linearly polarized TEM00 mode. The resonator is based on a symmetrical convex-convex structure with a two-rod configuration for birefringence compensation, working in a thermally near-unstable cavity. With an optimum cavity length of 940 mm, a 39.4 W linear polarized 1319 nm laser is obtained with a good beam quality of M 2  =  1.21 and a linewidth of ~250 MHz, and the corresponding brightness is as high as 1.55 GW cm-2. The laser is operated at a repetition rate of 500 Hz and pulse duration of 150 µs. To the best of our knowledge, this is the highest output power 1319 nm laser with narrow-linewidth from diode-pumped Nd:YAG lasers, and is the first report on the twisted-mode laser operation at the 1.3 µm region.

  16. Generation of high charge state platinum ions on vacuum arc plasma heated by gyrotron radiation.

    Science.gov (United States)

    Yushkov, G Yu; Vodopyanov, A V; Nikolaev, A G; Izotov, I V; Savkin, K P; Golubev, S V; Oks, E M

    2014-02-01

    The hybrid high charge metal ion source based on vacuum arc plasma heated by gyrotron radiation into simple magnetic trap has been developed. Two types of magnetic traps were used: a mirror configuration and a cusp one with inherent "minimum-B" structure. Pulsed high power (>100 kW) gyrotrons with frequency 37.5 GHz and 75 GHz were used for heating the vacuum arc plasma injected into the traps. Two different ways were used for injecting the metal plasma-axial injection by a miniature arc source located on-axis near the microwave window, and simultaneous radial injection by a number of sources mounted radially at the midplane of the traps. This article represents all data gathered for platinum ions, thus making comparison of the experimental results obtained with different traps and injections convenient and accurate.

  17. Cold test of cylindrical open resonator for 42 GHz, 200 kW gyrotron

    Indian Academy of Sciences (India)

    ),. Pilani 333 031, India ... design and fabrication of the specific gyrotron cavity. Keywords. Gyrotron; resonator; electric ... Recently in India, a program of design and development of the 42 GHz, 200 kW gyrotron has been initiated for the Indian.

  18. Local control unit for ITER-India gyrotron test facility (IIGTF)

    Energy Technology Data Exchange (ETDEWEB)

    Rathod, Vipal, E-mail: vipal.rathod@iter-india.org; Shah, Ronak; Mandge, Deepak; Parmar, Rajvi; Rao, S.L.

    2016-11-15

    Highlights: • A dedicated full scale ITER prototype Local Control Unit for ITER-India Gyrotron test facility. • National Instruments® make PXIe system for real time control & data acquisition and Siemens® PLC for sequence control function. • Hardwired FPGA based fast protection interlock system. • High speed analog fiber optical transmission link using V/F and F/V technique. • Software framework based on LabVIEW™ platform and ITER CODAC Core System. - Abstract: Electron Cyclotron system on ITER, is one of the important RF ancillary systems based on high power Gyrotron RF sources, that is used for plasma heating and current drive applications. To operate a Gyrotron source, various auxiliary systems and services such as Super Conducting Magnet set, High Voltage Power Supplies, Auxiliary Power Supplies, Waveguide components, Cooling water system and a Local Control Unit (LCU) are required. The LCU plays a very crucial role for the safe and reliable operation of Gyrotron system. A dedicated full scale ITER prototype LCU is being developed for testing and commissioning of an ITER like Test Gyrotron at ITER-India Gyrotron Test facility (IIGTF). The main functions of LCU include Sequence Control, Local Interlock Protection and Real Time Data Acquisition. PLC based slow controller is used for implementing the Sequence Control & Slow Interlock functions. Critical Protection Interlocks are required to have a response time of <10 μs and are implemented using custom built hardware and PXIe based fast controller. Also PXIe system is used for implementing Real Time Data Acquisition function that is required to have slow and fast acquisition with online visualization and off line analysis facility. A Signal Conditioning Unit (SCU) is used to interface and faithfully transmit the field signals to the remote control systems. Necessary controller hardware is procured and several pre-prototype developments have been taken up to establish the critical subsystems such as

  19. 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...

  20. 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.

  1. Magnetic field profile analysis for gyrotron experimental investigation

    Science.gov (United States)

    Pagonakis, Ioannis Gr.; Avramidis, Konstantinos A.; Gantenbein, Gerd; Rzesnicki, Tomasz; Samartsev, Andrey; Jelonnek, John

    2017-03-01

    The external applied magnetic field plays a main role on the gyrotron operation. Even if the gyrotron design is optimized for the nominal magnetic profile, it is possible the performance to be better for an alternative one. This unexpected result can happen for several reasons, such as the manufacturing imperfections, the misalignment issues, and several unknown factors in gyrotron theory and design. The systematic experimental investigation of the gyrotron in different magnetic profiles is very important for the optimization of the gyrotron operation and for the better understanding of the gyrotron behavior. In this sense, an analytical approach for the definition of the appropriate magnetic profiles based on the beam characteristics instead of the coil currents definition is proposed for a systematic experimental study. Using this technique, operational maps in the space of the important magnetic profile parameters are developed, which are very useful for the characterization of the gyrotron performance. For the demonstration of this idea, the operational maps of the short-pulse prototype of the 170 GHz, 1 MW European ITER gyrotron project are presented.

  2. 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...

  3. High power testing of water-cooled waveguide for ITER-like ECH transmission lines

    Science.gov (United States)

    Anderson, J. P.; Doane, J. L.; Grunloh, H. J.; O'Neill, R. C.; Ikeda, R.; Oda, Y.; Takahashi, K.; Sakamoto, K.

    2017-05-01

    The results of high power testing of new water-cooled ECH waveguide components for ITER are presented. The components are a precision-coupled 4.2 m waveguide assembly, a short expansion joint, and water-cooled waveguide for gyrotron commissioning. The testing was conducted at the QST Naka Fusion Institute using gyrotron pulses of 450 kW at 170 GHz for 300 s. Analysis shows that the power absorbed per unit length for the various waveguide components are dependent on location in the transmission line with respect to high order mode generators, such as miter bends. Additionally, larger-than-expected reflections from the load led to high absorption levels in the transmission line.

  4. Design of the all solid high-voltage power supply for a gyrotron body

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Yihua [School of Mathematics and Physics, University of South China, Hengyang, 421001 (China); Chen, Wenguang, E-mail: 430000485393@usc.edu.cn [School of Electrical Engineering, University of South China, Hengyang, 421001 (China); Hu, Bo [School of Electrical Engineering, University of South China, Hengyang, 421001 (China); Rao, Jun; Huang, Mei; Kang, Zihua; Feng, Kun [Southwestern Institute of Physics, Chengdu, 610041 (China); Huang, Jiaqi [School of Electrical Engineering, University of South China, Hengyang, 421001 (China)

    2017-04-15

    Highlights: • Completed design of all solid-state high-voltage power supply for gyrotron body on HL-2M ECRH. • Consist of 58 PSM modules and one BUCK module, controlled by DSP system. • Fabricated full voltage 35 kV, 200 mA BPS and tested in dummy load. • The BPS can operate in three modes: single pulse mode, multi-pulse modulation mode and the six-level preset mode. - Abstract: Gyrotron plays an important role in the research of electron cyclotron resonance heating (ECRH) on Tokomak. The high-frequency switched power supply technology and pulse step modulation (PSM) technology are used in the development of the all solid high-voltage body power supply (BPS) for 1 MW/105 GHz Gyrotron on ECRH system. Firstly, the basic structure of the BPS and its control system are introduced. Secondly, the software control algorithm of voltage stabilization and modulate method are developed. Finally, the design is verified by the experiments. The experimental results of the single pulse mode, the multi-pulse modulation mode and the six-level preset mode, are shown. The output voltage of the power supply can reach 35 kV and the current at about 200 mA, which are adjustable in the full range. The maximum modulation frequency can reach 1 kHz and the front edge of the pulse can be adjust from 0 to 3 ms and the accuracy of the output voltage is less than 100 V. The results show that the control method is feasible and can be applied to other high power microwave sources.

  5. 28 GHz Gyrotron ECRH on LDX

    Science.gov (United States)

    Woskov, P. P.; Kesner, J.; Michael, P. C.; Garnier, D. T.; Mauel, M. E.

    2010-12-01

    A 10 kW, CW, 28 GHz gyrotron has been implemented on LDX to increase the plasma density and to more fully explore the potential of high beta plasma stability in a dipole magnetic configuration. This added power represents about a 60% increase in ECRH to a new total of 26.9 kW with sources at 2.45, 6.4, and 10.5 GHz. The 1 Tesla resonances in LDX form small rings encompassing the entire plasma cross-section above and below the floating coil (F-coil) near the dipole axial region. A 32.5 mm diameter TE01 waveguide with a partial Vlasov step cut launches a diverging beam from above the F-coil that depends on internal wall reflections for plasma coupling. Initial gyrotron only plasmas exhibit steep natural profiles with fewer hot electrons than with the other sources. The background scattered radiation suggests that only about half the power is being absorbed with the present launcher.

  6. 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.

  7. Electrical and thermo-mechanical analysis of beam recovery system for megawatt power gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Ranajoy, E-mail: joy_trm@yahoo.com [Central Electronics Engineering Research Institute (CEERI), Pilani, Rajasthan 333031 (India); Sahu, Naveen Kr [Central Electronics Engineering Research Institute (CEERI), Pilani, Rajasthan 333031 (India); Khan, Arani Ali [Department of Electronics and Communication, Indian Institute of Technology, Kharagpur (India); Khatun, Hasina; Sinha, A.K. [Central Electronics Engineering Research Institute (CEERI), Pilani, Rajasthan 333031 (India)

    2013-05-15

    Highlights: • Electrical design of single stage depressed collector for high power gyrotron tube. • Efficiency enhancement by collecting spent beam. • Optimization of geometry and magnetic field for optimized beam spread. • Optimization of cooling duct system for better thermal management. -- Abstract: The paper presents the electrical and thermo-mechanical design of single stage beam recovery system for 120 GHz, 1 MW gyrotron. The electrical study shows that the cylindrical shape single stage beam recovery system enhances the efficiency by 66.26%. The maximum power deposited to collector in depressed collector operation is 0.48 MW for electronic efficiency, 30% and 1.44 MW for DC electron beam. The thermo-mechanical analysis has been performed to evaluate the water cooling system. The cooling system has capability of accommodating a peak wall loading, 0.9 kW/cm{sup 2} at flow rate of 1500 l/min for safe operating time, 60 ms. Further, a high voltage analysis is also carried out to appraise the electric field distribution in the collector.

  8. A simple quantum-electronic approach to the Gyrotron and its application to the solid-state gyrotron

    Science.gov (United States)

    Ho, P.-T.; Granatstein, V. L.

    1986-01-01

    A simple, unifying theory of the gyrotron is presented. It is of the Lamb type. Within its framework, important results from different approaches can be easily obtained. As an application, gyrotron action in InSb is reexamined, and coherent emission at 10 to the 12th Hz appears possible with an output power of about 0.5 mW/sq mm of the device.

  9. Finite-Bandwidth Resonances of High-Order Axial Modes (HOAM) in a Gyrotron Cavity

    OpenAIRE

    Sabchevski, Svilen; IDEHARA, Toshitaka

    2014-01-01

    Finite-bandwidth resonances of high-order axial modes (HOAM) in an open gyrotron cavity are studied numerically using the GYROSIM problem-oriented software package for modelling, simulation and computer-aided design (CAD) of gyrotron tubes.

  10. Velocity-space tomography of fusion plasmas by collective Thomson scattering of gyrotron radiation

    DEFF Research Database (Denmark)

    Salewski, Mirko; Jacobsen, A.S.; Jensen, Thomas

    2016-01-01

    We propose a diagnostic capable of measuring 2D fast-ion velocity distribution functions 푓2퐷푣 in the MeV-range in magnetized fusion plasmas. Today velocity-space tomography based on fast-ion D훼 spectroscopy is regularly used to measure 푓2퐷푣 for ion energies below 100 keV. Unfortunately, the signal......-tonoise ratio becomes fairly low for MeV-range ions. Ions at any energy can be detected well by collective Thomson scattering of mm-wave radiation from a high-power gyrotron. We demonstrate how collective Thomson scattering can be used to measure 푓2퐷푣 in the MeV-range in reactor relevant plasmas...

  11. Effect of ion compensation of the beam space charge on gyrotron operation

    Energy Technology Data Exchange (ETDEWEB)

    Fokin, A. P.; Glyavin, M. Yu. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Nusinovich, G. S. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742-3511 (United States)

    2015-04-15

    In gyrotrons, the coherent radiation of electromagnetic waves takes place when the cyclotron resonance condition between the wave frequency and the electron cyclotron frequency or its harmonic holds. The voltage depression caused by the beam space charge field changes the relativistic cyclotron frequency and, hence, can play an important role in the beam-wave interaction process. In long pulse and continuous-wave regimes, the beam space charge field can be partially compensated by the ions, which appear due to the beam impact ionization of neutral molecules of residual gases in the interaction space. In the present paper, the role of this ion compensation of the beam space charge on the interaction efficiency is analyzed. We also analyze the effect of the electron velocity spread on the limiting currents and discuss some effects restricting the ion-to-beam electron density ratio in the saturation stage. It is shown that the effect of the ion compensation on the voltage depression caused by the beam space charge field can cause significant changes in the efficiency of gyrotron operation and, in some cases, even result in the break of oscillations.

  12. 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

  13. High-power direct green laser oscillation of 598 mW in Pr(3+)-doped waterproof fluoroaluminate glass fiber excited by two-polarization-combined GaN laser diodes.

    Science.gov (United States)

    Nakanishi, Jun; Horiuchi, Yuya; Yamada, Tsuyoshi; Ishii, Osamu; Yamazaki, Masaaki; Yoshida, Minoru; Fujimoto, Yasushi

    2011-05-15

    We demonstrated a high-power and highly efficient Pr-doped waterproof fluoride glass fiber laser at 522.2 nm excited by two-polarization-combined GaN laser diodes and achieved a subwatt output power of 598 mW and slope efficiency of 43.0%. This system will enable us to make a vivid laser display, a photocoagulation laser for eye surgery, a color confocal scanning laser microscope, and an effective laser for material processing. Direct visible ultrashort pulse generation is also expected. © 2011 Optical Society of America

  14. 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.

  15. 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.

  16. Electron beam gun with kinematic coupling for high power RF vacuum devices

    Energy Technology Data Exchange (ETDEWEB)

    Borchard, Philipp

    2016-11-22

    An electron beam gun for a high power RF vacuum device has components joined by a fixed kinematic coupling to provide both precise alignment and high voltage electrical insulation of the components. The kinematic coupling has high strength ceramic elements directly bonded to one or more non-ductile rigid metal components using a high temperature active metal brazing alloy. The ceramic elements have a convex surface that mates with concave grooves in another one of the components. The kinematic coupling, for example, may join a cathode assembly and/or a beam shaping focus electrode to a gun stem, which is preferably composed of ceramic. The electron beam gun may be part of a high power RF vacuum device such as, for example, a gyrotron, klystron, or magnetron.

  17. 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...

  18. Experimental Verification on Remote Detectability of Concealed Radioactive Material Based on the Plasma Discharge Delay Time using High-Power Millimeter-Wave

    Science.gov (United States)

    Kim, Dongsung; Yu, Dongho; Sawant, Ashwini; Choe, Mun Seok; Lee, Ingeun; Choi, Eunmi

    2016-10-01

    We experimentally demonstrate a remote detection method of a radioactive source by plasma breakdown using high-power millimeter-wave source, gyrotron. A number of free electrons near the radioactive source are much higher than those of without the radioactive source (roughly 10 particles/cm3) owing to the interaction of air molecules and strong gamma rays generated by radioactive material. The RF wave beam is focused in ambient air, and the plasmas discharge occurs involving random delay time which means a time interval between the RF wave and a fluorescent light caused by the plasma. We observed that the delay time decreased significantly due to the high density of free electrons in Ar plasma with an existence of Co60 radioactive material. This technique of delay time measurement shows 1000 times more sensitive than a method of detectable mass equation to identify the existence of radioactive source remotely. It is the first experimental verification of radioactive material detection using a high power gyrotron. This study shows that a remote detection of radioactive material based on analysis of precise delay time measurement could be feasible by using a high power millimeter/THz wave gyrotron. NRF-2013R1A1A2061062, NRF-2012-Global Ph.D. Fellowship Program.

  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-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.

  1. Operating experience on six 110 GHz, 1 MW gyrotrons for ECH applications

    Science.gov (United States)

    Felch, K.; Blank, M.; Borchard, P.; Cahalan, P.; Cauffman, S.; Jory, H.; Gorelov, Y.; Lohr, J.

    2008-05-01

    Since 1999, CPI has shipped six, 110 GHz, 1 MW, 5 s pulsed gyrotrons to General Atomics (GA) for use in electron cyclotron heating experiments on the DIII-D tokamak. As a result of extensive testing of these gyrotrons at CPI and GA, a wealth of information has been obtained regarding the long-term performance of the original electrical and mechanical design of the tubes. All of the gyrotrons have achieved long-pulse operation and five of the six gyrotrons achieved 1 MW output power levels with the nominal beam voltage and current of 80 kV and 40 A, respectively. Experience with the electron guns and interaction cavities has been quite good, though the low efficiency experienced by one gyrotron may be attributed to a gun or cavity irregularity. The internal converters employed in the gyrotrons have produced high-quality Gaussian output beams with internal diffractions losses of 5-6.5%. After several years of operation, the first three 110 GHz gyrotrons experienced collector failures due to cyclic fatigue. Improved analyses and diagnostics have been employed to avoid these problems in the future. Two problems have been experienced with the diamond output windows. These problems have been eliminated by changing braze techniques and procedures. Based on the experience obtained on these six gyrotrons, recommendations can be made for future gyrotron development work.

  2. 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.

  3. Startup and mode competition in a 420 GHz gyrotron

    Science.gov (United States)

    Qixiang Zhao, A.; Sheng Yu, B.; Tianzhong Zhang, C.

    2017-09-01

    In the experiments of a 420 GHz second-harmonic gyrotron, it is found that the electron beam voltage and current ranges for single mode operation of TE17.4 are slightly narrower than those in the simulation. To explain this phenomenon, the startup scenario has been investigated with special emphasis on mode competition. The calculations indicate that the decreases of the operating ranges are caused by the voltage overshoot in the startup scenario.

  4. Application of Novel Focusing Mirrors in Gyrotron Transmission Lines

    OpenAIRE

    Ogawa, I.; Miyake, Y.; IDEHARA, T; SABCHEVSKI, S

    2002-01-01

    A novel focusing mirror based on the shifting of the beam phase according to the Gaussian beam optics enabled us to realize a focusing elements with different focal lengths in different directions and to convert the gyrotron output into a Gaussian-like beam. In this paper, we compare the quality of beams produced by the new system (which includes novel mirrors) and a conventional system consisting of a quasi-optical antenna, an ellipsoidal mirror and two parabolic cylinder mirrors.

  5. 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.

  6. Diode pumped 1kHz high power Nd:YAG laser with excellent beam quality

    NARCIS (Netherlands)

    Godfried, Herman; Godfried, H.P; Offerhaus, Herman L.

    1997-01-01

    The design and operation of a one kilohertz diode pumped all solid-state Nd:YAG master oscillator power amplifier system with a phase conjugate mirror is presented. The setup allows high power scaling without reduction in beam quality.

  7. Current drive and mode stabilization experiments with real-time control of the gyrotron output power

    NARCIS (Netherlands)

    Oomens, A. A. M.; Lok, J.; Salzedas, F.; Schüller, F. C.; Dam, R.; de Groot, B.; R. T. P. Team,

    2001-01-01

    Real-time control of the gyrotron output power has been obtained by controlling the gyrotron cathode voltage. This control system has been used to explore feedback control of global and local plasma parameters. A description is given of technical set-up and of the results, which include control of

  8. 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.

  9. Dielectric properties during electron irradiation of alternative materials for gyrotron windows

    Energy Technology Data Exchange (ETDEWEB)

    Vila, R. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain). Inst. de Investigacion Basica; Ibarra, A. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain). Inst. de Investigacion Basica; Hodgson, E.R. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain). Inst. de Investigacion Basica

    1996-10-01

    Recent work on high power gyrotron windows has focused interest on some homopolar insulators as alternatives to sapphire due to their combined low dielectric loss and high thermal conductivity. The two main candidates at this moment, CVD diamond and high resistivity silicon, have been studied. As an indicator of their radiation behaviour, loss tangent and permittivity at about 15 GHz have been measured under 1.8 MeV electron irradiation at RT. In the case of silicon the previously observed radiation-induced decrease of loss tangent has been confirmed reaching a lower saturation level of 3.5 x 10{sup -5} at higher doses, and falling with increasing frequency. An even more important observation is that the sensitivity to ionizing radiation dropped by 4 orders of magnitude due to the radiation dose. First results for diamond are also promising, only a small degradation at relatively short times being seen with no further changes up to the maximum dose used. (orig.).

  10. 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.

  11. High Power Room Temperature Terahertz Local Oscillator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The motivation of the proposed SBIR is to develop, demonstrate and commercialize a compact, low-mass, high output power (1-10 milliwatt), tunable source of CW THz...

  12. 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.

  13. Stabilization of Gyrotron Frequency by PID Feedback Control on the Acceleration Voltage

    Science.gov (United States)

    Khutoryan, E. M.; Idehara, T.; Kuleshov, A. N.; Tatematsu, Y.; Yamaguchi, Y.; Matsuki, Y.; Fujiwara, T.

    2015-12-01

    The results of frequency stabilization by proportional-integral-derivative (PID) feedback control of acceleration voltage in the 460-GHz Gyrotron FU CW GVI (the official name in Osaka University is Gyrotron FU CW GOI) are presented. The experiment was organized on the basis of the frequency modulation by modulation of acceleration voltage of beam electrons. The frequency stabilization during 10 h experiment was better than 10-6, which is compared with the results of the frequency deviation in free-running gyrotron operation.

  14. A 0.4-THz Second Harmonic Gyrotron with Quasi-Optical Confocal Cavity

    Science.gov (United States)

    Guan, Xiaotong; Fu, Wenjie; Yan, Yang

    2017-12-01

    Mode density is very relevant for harmonic gyrotron cavity. Theoretical investigations suggest that quasi-optical confocal waveguide performs low mode density and good mode-selective character. By selecting the appropriate mode and optimizing the cavity parameters, the quasi-optical confocal cavity is suitable for high-harmonic terahertz gyrotron without mode competition. In order to verify the theoretical analysis, a 0.4-THz second harmonic gyrotron has been designed and experimented. Driven by a 40-kV, 4.75-A electron beam and 7.51-T magnetic field, the gyrotron prototype could generate 6.44 kW of output power at 395.35 GHz, which corresponds to an electron efficiency of 3.4%. There is no mode competition between the second harmonic and fundamental observed in the experiments.

  15. Operation of a sub-terahertz CW gyrotron with an extremely low voltage

    Science.gov (United States)

    Bratman, V. L.; Fedotov, A. E.; Fokin, A. P.; Glyavin, M. Yu.; Manuilov, V. N.; Osharin, I. V.

    2017-11-01

    Decreasing the operating voltage for medium-power sub-terahertz gyrotrons aimed at industrial and scientific applications is highly attractive, since it allows size and cost reduction of the tubes and power supply units. In this paper, we examine such an opportunity both numerically and experimentally for the fundamental cyclotron resonance operation of an existing gyrotron initially designed for operation at the second cyclotron harmonic with a relatively high voltage. Simulations predict that output power higher than 10 W can be produced at the fundamental harmonic at voltages less than 2 kV. To form a low-voltage helical electron beam with a sufficiently large pitch-factor, a positive voltage was applied to the first anode of the gyrotron three-electrode magnetron-injection gun with a negative voltage at the cathode. CW gyrotron operation at voltages down to 1.5 kV has been demonstrated at a frequency about of 256 GHz.

  16. Development of gyrotron traveling-wave tubes at IAP and GYCOM

    Science.gov (United States)

    Samsonov, S. V.; Denisov, G. G.; Gachev, I. G.; Bogdashov, A. A.; Mishakin, S. V.; Manuilov, V. N.; Belousov, V. I.; Sobolev, D. I.; Sokolov, E. V.; Soluyanova, E. A.; Tai, E. M.

    2017-08-01

    A brief review of research activity on gyrotron traveling-wave tube amplifiers (gyro-TWTs) with helically corrugated waveguides developing by the Institute of Applied Physics and GYCOM (Nizhny Novgorod, Russia) will be presented.

  17. Initiation of dusty structures in chain reactions under the action of gyrotron radiation on a mixture of metal and dielectric powders with an open boundary

    Science.gov (United States)

    Skvortsova, N. N.; Malakhov, D. V.; Stepakhin, V. D.; Maiorov, S. A.; Batanov, G. M.; Borozosekov, V. D.; Konchekov, E. M.; Kolik, L. V.; Letunov, A. A.; Obraztsova, E. A.; Petrov, A. E.; Pozdnyakov, D. O.; Sarksyan, K. A.; Sorokin, A. A.; Ukryukov, G. V.; Kharchev, N. K.

    2017-08-01

    A dusty plasma formed in chain exothermal reactions initiated by radiation of a high-power gyrotron in mixtures of metal and dielectric powders has been described. An oscillatory character of such chain reactions, as well as the appearance of dust particles at the first (explosive) stage, has been detected. The tracks, velocities, and sizes of dust particles have been measured. It has been revealed that ensembles of dust particles appear in a reactor after switching-off of the gyrotron against the background of development of chemical reactions. The time of existence of these ensembles is three or four orders of magnitude larger than the duration of a microwave radiation pulse. The quasistationary state of the low-temperature plasma with charged macroparticles appears because of both the chemical heating of the mixture in the reactor and thermophoresis. It has been shown that dust particles are necessary as crystallization nuclei for the creation (or deposition) of complex composites of nano- and micromaterials produced in secondary plasma chemical synthesis.

  18. Simulation of a high harmonic gyrotron with axis-encircling beam and permanent magnet

    OpenAIRE

    S.P.SABCHEVSKI; IDEHARA, T; Ogawa, I.; M.GLYAVIN; Ohashi , K.

    2002-01-01

    A compute code for simulation of beam-field interaction in a resonant cavity of a gyrotron has been developed. It is based on a self-consistent, time-independent, single-mode physical model. The code has been applied to the analysis of the electrodynamical system of a novel high-harmonic gyrotron physical model and the use of the numerical experiment are presented and discussed.

  19. Development of simulation tools for numerical investigation and computer-aided design (CAD) of gyrotrons

    Science.gov (United States)

    Damyanova, M.; Sabchevski, S.; Zhelyazkov, I.; Vasileva, E.; Balabanova, E.; Dankov, P.; Malinov, P.

    2016-10-01

    As the most powerful CW sources of coherent radiation in the sub-terahertz to terahertz frequency range the gyrotrons have demonstrated a remarkable potential for numerous novel and prospective applications in the fundamental physical research and the technologies. Among them are powerful gyrotrons for electron cyclotron resonance heating (ECRH) and current drive (ECCD) of magnetically confined plasma in various reactors for controlled thermonuclear fusion (e.g., tokamaks and most notably ITER), high-frequency gyrotrons for sub-terahertz spectroscopy (for example NMR-DNP, XDMR, study of the hyperfine structure of positronium, etc.), gyrotrons for thermal processing and so on. Modelling and simulation are indispensable tools for numerical studies, computer-aided design (CAD) and optimization of such sophisticated vacuum tubes (fast-wave devices) operating on a physical principle known as electron cyclotron resonance maser (ECRM) instability. During the recent years, our research team has been involved in the development of physical models and problem-oriented software packages for numerical analysis and CAD of different gyrotrons in the framework of a broad international collaboration. In this paper we present the current status of our simulation tools (GYROSIM and GYREOSS packages) and illustrate their functionality by results of numerical experiments carried out recently. Finally, we provide an outlook on the envisaged further development of the computer codes and the computational modules belonging to these packages and specialized to different subsystems of the gyrotrons.

  20. Development of a high power wideband polarizer for electron cyclotron current drive system in JT-60SA

    Energy Technology Data Exchange (ETDEWEB)

    Saigusa, Mikio, E-mail: saigusa@mx.ibaraki.ac.jp [Ibaraki University, Hitachi, Ibaraki 316-8511 (Japan); Oyama, Gaku; Matsubara, Fumiaki; Takii, Keita; Sai, Takuma [Ibaraki University, Hitachi, Ibaraki 316-8511 (Japan); Kobayashi, Takayuki; Moriyama, Shinichi [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan)

    2015-10-15

    Highlights: • We developed a new wideband polarizer for JT-60SA ECCD system. • The wideband polarizer is optimized for dual frequency gyrotrons (110 and 138 GHz) in JT-60SA. • The wideband polarization properties were verified at cold tests. • The preliminary high power tests have been carried out at 0.25 MW, 3 s at 110 GHz. - Abstract: A wideband polarizer consisting of a polarization twister and a circular polarizer has been developed for an electron cyclotron current driving system in JT-60SA, where the output frequencies of a dual frequency gyrotron for JT-60SA are 110 and 138 GHz. The groove depths are optimized for the dual frequencies by numerical simulations using a FDTD method and cold test results. The polarization properties of a mock-up polarizer are measured at the dual frequencies in cold tests. The cold test results suggest that all practical polarizations for ECCD experiments can be achieved at the dual frequencies. The prototype polarization twister has been tested up to 0.25 MW during 3 s at the frequency of 110 GHz.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  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. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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....

  12. 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

  13. 60 GHz gyrotron development program. Final report, April 1979-June 1984

    Energy Technology Data Exchange (ETDEWEB)

    Shively, J.F.; Bier, R.E.; Caplan, M.; Cheng, M.K.; Choi, E.; Conner, C.C.; Craig, L.J.; Evans, S.J.; Evers, S.J.; Felch, K.L.

    1986-01-01

    The original objective of this program was to develop a microwave amplifier or oscillator capable of producing 200 kW CW power output at 110 GHz. The use of cyclotron resonance interaction was pursued, and the design phases of this effort are discussed. Later, however, the program's objective was changed to develop a family of oscillators capable of producing 200 kw of peak output power at 60 GHz. Gyrotron behavior studies were performed at 28 GHz to obtain generic design information as quickly as possible. The first experimental device at 60 GHz produced over 200 kw of peak power at a pulse duration of 20 ..mu..s. Heating problems and mode interference were encountered. The second experimental tube incorporated an optimized gun location but also suffered from mode interference. The third experimental tube included modifications that reduced mode interference. It demonstrated 200 kw of peak output at 100 ms pulse duration. The fourth experimental tube, which used an older rf circuit design but in a CW configuration, produced 71.5 kW CW. The fifth experimental tube incorporated a thinner double-disc output window which improved window bandwidth and reduced window loss. This tube also incorporated modifications to the drift tunnel and cavity coupling, which had proven successful in the third experimental pulse tube tests. It produced 123 kW of CW output power at 60 GHz rf load coolant boiling and tube window failure terminated the tests. A new waterload was designed and constructed, and alternative window designs were explored. A secondary task of developing a 56 GHz CW tube produced in excess of 100 kW CW at this alternate frequency. Testing of the sixth experimental tube resulted in operation at CW output power in the range of 200 to 206 kW for an hour. Output mode purity of the seventh experimental tube was measured at 95% TE/sub 02/. The tube was operated for about forty-five minutes with CW power output over 200 kW.

  14. 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...

  15. 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 ...

  16. Possible standoff detection of ionizing radiation using high-power THz electromagnetic waves

    Science.gov (United States)

    Nusinovich, Gregory S.; Sprangle, Phillip; Romero-Talamas, Carlos A.; Rodgers, John; Pu, Ruifeng; Kashyn, Dmytro G.; Antonsen, Thomas M., Jr.; Granatstein, Victor L.

    2012-06-01

    Recently, a new method of remote detection of concealed radioactive materials was proposed. This method is based on focusing high-power short wavelength electromagnetic radiation in a small volume where the wave electric field exceeds the breakdown threshold. In the presence of free electrons caused by ionizing radiation, in this volume an avalanche discharge can then be initiated. When the wavelength is short enough, the probability of having even one free electron in this small volume in the absence of additional sources of ionization is low. Hence, a high breakdown rate will indicate that in the vicinity of this volume there are some materials causing ionization of air. To prove this concept a 0.67 THz gyrotron delivering 200-300 kW power in 10 microsecond pulses is under development. This method of standoff detection of concealed sources of ionizing radiation requires a wide range of studies, viz., evaluation of possible range, THz power and pulse duration, production of free electrons in air by gamma rays penetrating through container walls, statistical delay time in initiation of the breakdown in the case of low electron density, temporal evolution of plasma structure in the breakdown and scattering of THz radiation from small plasma objects. Most of these issues are discussed in the paper.

  17. 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

  18. 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.

  19. The NRL (Naval Research Laboratory) Phase-Locked Gyrotron Oscillator Program for SDIO/IST

    Science.gov (United States)

    1988-07-11

    PREDICTED POWER vs RADIUS 0 .l~n2 10E 2 / lEv I 0 LOC) TE6 mode >0 0 0 0.0 5.0 10.0 15.0 RADIUS (cm) Fig. V.5. Predicted output power vs radius for...Studies College Park, Maryland 20742 Attn: Dr. Jhan Varyan Hellman 1 copy Dr. John Finn 1 copy Dr. Baruch Levpsh 1 copy Dr. Tom Antonsen 1 copy Dr

  20. 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.

  1. 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.

  2. Start-Up Scenario in Gyrotrons with a Nonstationary Microwave-Field Structure

    Science.gov (United States)

    Nusinovich, G. S.; Yeddulla, M.; Antonsen, T. M., Jr.; Vlasov, A. N.

    2006-03-01

    Megawatt class gyrotrons operate in very high-order modes. Therefore, control of a gyrotron oscillator’s start-up is important for excitation of the desired mode in the presence of the many undesired modes. Analysis of such scenario using the self-consistent code MAGY [M. Botton , IEEE Trans. Plasma Sci. 26,ITPSBD0093-3813 882 (1998)10.1109/27.700860] reveals that during start-up not only mode amplitudes vary in time, but also their axial structure can be time dependent. Simulations done for a 1.5 MW gyrotron show that the excitation of a single operating TE22,6 mode can exhibit a sort of intermittency when, first, it is excited as a mode whose axial structure extends outside the interaction cavity, then it ceases and then reappears as a mode mostly localized in the cavity. This phenomenon makes it necessary to analyze start-up scenarios in such gyrotrons with the use of codes that account for the possible evolution of field profiles.

  3. Performance History and Upgrades for the DIII-D Gyrotron Complex

    Directory of Open Access Journals (Sweden)

    Lohr J.

    2015-01-01

    Full Text Available The gyrotron installation on the DIII-D tokamak has been in operation at the second harmonic of the electron cyclotron resonance since the mid-1990s. Prior to that a large installation of ten 60 GHz tubes was operated at the fundamental resonance. The system has been upgraded regularly and is an everyday tool for experiments on DIII-D.

  4. High efficiency coupling of radio frequency beams from the dual frequency gyrotron with a corrugated waveguide transmission system.

    Science.gov (United States)

    Oda, Yasuhisa; Kajiwara, Ken; Takahashi, Koji; Mitsunaka, Yoshika; Sakamoto, Keishi

    2013-01-01

    High efficiency coupling of the millimeter-wave output of the dual-frequency gyrotron with the transmission line was demonstrated. The dual-frequency gyrotron was design to produce similar beam profiles for two operation frequencies (170 GHz and 137 GHz). Using two RF beam reflecting mirrors in a matching optics unit (MOU), which are designed to transform the beam profile of the gyrotron output to the fundamental waveguide mode (HE(11) mode) at 170 GHz, high efficiency coupling was demonstrated for two frequencies. The measured mode purity of HE(11) mode was 96% at 170 GHz and 94% at 137 GHz operations with the identical mirrors at the fixed mirror position and angle. The results indicate that the significantly simple dual frequency system is realized by the gyrotron designed to output the similar beam profiles at different frequency operation.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. High power double-scale pulses from a gain-guided double-clad fiber laser

    Science.gov (United States)

    Zhang, Haitao; Gao, Gan; Li, Qinghua; Gong, Mali

    2017-03-01

    Generation of high power double-scale pulses from a gain-guided double-clad fiber laser is experimentally demonstrated. By employing the Yb-doped 10/130 double-clad fiber as the gain medium, the laser realizes an output power of 5.1 W and pulse energy of 0.175 µJ at repetition rate of 29.14 MHz. To the best of our knowledge, this average output power is the highest among the reported double-scale pulse oscillators. The autocorrelation trace of pulses contains the short (98 fs) and long (29.5 ps) components, and the spectral bandwidth of the pulse is 27.3 nm. Such double-scale pulses are well suited for seeding the high power MOPA (master oscillator power amplifier) systems, nonlinear frequency conversion and optical coherence tomography.

  13. 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.

  14. Status of the development of the EU 170 GHz/1 MW/CW gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Pagonakis, Ioannis Gr., E-mail: ioannis.pagonakis@kit.edu [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Albajar, Ferran [The European Joint Undertaking for ITER and The Development of Fusion Energy, Barcelona (Spain); Alberti, Stefano [École Polytechnique Fédérale de Lausanne, Centre de Recherches en Physique des Plasmas (CRPP), Lausanne (Switzerland); Avramidis, Konstantinos [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Bonicelli, Tullio [The European Joint Undertaking for ITER and The Development of Fusion Energy, Barcelona (Spain); Braunmueller, Falk [École Polytechnique Fédérale de Lausanne, Centre de Recherches en Physique des Plasmas (CRPP), Lausanne (Switzerland); Bruschi, Alex [Plasma Physics Institute, National Research Council of Italy, Milano (Italy); Chelis, Ioannis [School of Electrical and Computer Engineering, National Technical University of Athens (Greece); Cismondi, Fabio [The European Joint Undertaking for ITER and The Development of Fusion Energy, Barcelona (Spain); Gantenbein, Gerd [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Hermann, Virgile [Thales Electron Devices (TED), Vélizy-Villacoublay (France); Hesch, Klaus [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Hogge, Jean-Philippe [École Polytechnique Fédérale de Lausanne, Centre de Recherches en Physique des Plasmas (CRPP), Lausanne (Switzerland); Jelonnek, John; Jin, Jianbo; Illy, Stefan [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Ioannidis, Zisis C. [Faculty of Physics, National and Kapodistrian University of Athens (Greece); Kobarg, Thorsten [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); and others

    2015-10-15

    The progress in the development of the European 170 GHz, 1 MW/CW gyrotron for electron cyclotron heating & current drive (ECH&CD) on ITER is reported. A continuous wave (CW) prototype is being manufactured by Thales Electron Devices (TED), France, while a short-pulse (SP) prototype gyrotron is in parallel under manufacture at Karlsruhe Institute of Technology (KIT), with the purpose of validating the design of the CW industrial prototype components. The fabrication of most of the sub-assemblies of the SP prototype has been completed. In a first step, an existing magnetron injection gun (MIG) available at KIT was used. Despite this non-ideal configuration, the experiments provided a validation of the design, substantiated by an excellent agreement with numerical simulations. The tube, operated without a depressed collector, is able to produce more than 1 MW of output power with efficiency in excess of 30%, as expected, and compatible with the ITER requirements.

  15. Modelling and simulation of new generation powerful gyrotrons for the fusion research

    Energy Technology Data Exchange (ETDEWEB)

    Sabchevski, S [Institute of Electronics, Bulgarian Academy of Sciences, BG-1784 Sofia (Bulgaria); Zhelyazkov, I [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria)

    2007-04-15

    One of the important issues related with the cyclotron resonance heating (CRH) and current drive of fusion plasmas in thermonuclear reactors (tokamaks and stellarators) is the development of multi-megawatt class gyrotrons. There are generally three stages of the implementation of that task, notably (i) elaborating a novel generation of software tools for the physical modelling and simulation of such kind of gyrotrons, (ii) their computer aided design (CAD) and construction on the basis of the simulation's results, and finally, (iii) gyrotrons' testing in real experimental conditions. This tutorial paper concerns the first item-the development of software tools. In co-operation with the Institute for Pulsed Power and Microwave Technology at the Forschungszentrum Karlsruhe, Germany, and Centre de Recherches en Physique des Plasmas at Ecole Polytechnique Federale de Lausanne, Switzerland, we work on the conceptual design of the software tools under development. The basic conclusions are that the numerical codes for gyrotrons' modelling should possess the following essential characteristics: (a) portability, (b) extensibility, (c) to be oriented toward the solution of practical problems (i.e., elaborating of computer programs that can be used in the design process), (d) to be based on self-consistent 3D physical models, which take into account the departure from axial symmetry, and (e) ability to simulate time dependent processes (electrostatic PIC simulation) alongside with a trajectory analysis (ray tracing simulation). Here, we discuss how various existing numerical codes have to be improved and implemented via the advanced programming technologies for state-of-the-art computer systems including clusters, grid, parallel platforms, and supercomputers.

  16. Pre- and post-processing of data for simulation of gyrotrons by the GYREOSS software package

    Energy Technology Data Exchange (ETDEWEB)

    Damyanova, M; Sabchevski, S [Academician Emil Djakov Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradso Schaussee Blvd., BG-1784 Sofia (Bulgaria); Zhelyazkov, I, E-mail: sabchevski@yahoo.co [Faculty of Physics, Sofia University, 5 James Bourchier Blvd., BG-1164 Sofia (Bulgaria)

    2010-01-01

    In this paper, we present the concept of the pre- and post-processing of data for simulation of gyrotrons by the GYREOSS software package, which is being developed now. It is based on the utilization of an appropriate code for description and input of the geometry of the tube in three dimensions, for discretization of the computational region by unstructured tetrahedral mesh and for visualization and manipulation of the results of numerical experiments.

  17. Time-domain theory of gyrotron traveling wave amplifiers operating at grazing incidence

    Energy Technology Data Exchange (ETDEWEB)

    Ginzburg, N. S., E-mail: ginzburg@appl.sci-nnov.ru [Institute of Applied Physics of the Russian Academy of Sciences, 46, Ul' yanov St., Nizhny Novgorod (Russian Federation); Nizhny Novgorod State University, Gagarin Ave., 23, 603950 Nizhny Novgorod (Russian Federation); Sergeev, A. S.; Zotova, I. V.; Zheleznov, I. V. [Institute of Applied Physics of the Russian Academy of Sciences, 46, Ul' yanov St., Nizhny Novgorod (Russian Federation)

    2015-01-15

    Time-domain theory of the gyrotron traveling wave tube (gyro-TWT) operating at grazing incidence has been developed. The theory is based on a description of wave propagation by a parabolic equation. The results of the simulations are compared with experimental results of the observation of subnanosecond pulse amplification in a gyro-TWT consisting of three gain sections separated by severs. The theory developed can also be used successfully for a description of amplification of monochromatic signals.

  18. Modelling and Simulation of Magnetron Infection Guns for Submillimeter Wave Gyrotrons

    OpenAIRE

    S.P.SABCHEVSKI; G.M.Mladenov; IDEHARA, T

    1999-01-01

    The software package GUN-MIG has been developed for computer simulation of beam formation in magnetron injection guns (MIG). It is based on a fully relativistic self-consistent physical model which takes into account the specific problems and requirements that are being encountered in the analysis and design of MIG for gyrotrons. Besides providing a general outline of the physical models and the program implementation of the code, several illustrative examples of the numerical experiments wit...

  19. High power microwave diagnostic for the fusion energy experiment ITER

    DEFF Research Database (Denmark)

    Korsholm, Søren Bang; Leipold, Frank; Goncalves, B.

    2016-01-01

    Microwave diagnostics will play an increasingly important role in burning plasma fusion energy experiments like ITER and beyond. The Collective Thomson Scattering (CTS) diagnostic to be installed at ITER is an example of such a diagnostic with great potential in present and future experiments....... The ITER CTS diagnostic will inject a 1 MW 60 GHz gyrotron beam into the ITER plasma and observe the scattering off fluctuations in the plasma — to monitor the dynamics of the fast ions generated in the fusion reactions....

  20. Update on the DIII-D ECH system: experiments, gyrotrons, advanced diagnostics, and controls

    Directory of Open Access Journals (Sweden)

    Lohr John

    2017-01-01

    Full Text Available The ECH system on DIII-D is continuing to be upgraded, while simultaneously being operated nearly daily for plasma experiments. The latest major hardware addition is a new 117.5 GHz gyrotron, which generated 1.7 MW for short pulses during factory testing. A new gyrotron control system based on Field Programmable Gate Array (FPGA technology with very high speed system data acquisition has significantly increased the flexibility and reliability of individual gyrotron operation. We have improved the performance of the fast mirror scanning, both by increasing the scan speeds and by adding new algorithms for controlling the aiming using commands generated by the Plasma Control System (PCS. The system is used for transport studies, ELM control, current profile control, non-inductive current generation, suppression of MHD modes, startup assist, plasma density control, and other applications. A program of protective measures, which has been in place for more than two years, has eliminated damage to hardware and diagnostics caused by overdense operation. Other activities not directly related to fusion research have used the ECH system to test components, study methods for improving production of semiconductor junctions and materials, and test the feasibility of using ground based microwave systems to power satellites into orbit.

  1. Microwave method for synthesis of micro- and nanostructures with controllable composition during gyrotron discharge

    Science.gov (United States)

    Batanov, German M.; Borzosekov, Valentin D.; Golberg, Dmitri; Iskhakova, Ludmila D.; Kolik, Leonid V.; Konchekov, Evgeny M.; Kharchev, Nikolai K.; Letunov, Alexander A.; Malakhov, Dmitry V.; Milovich, Filipp O.; Obraztsova, Ekaterina A.; Petrov, Alexander E.; Ryabikina, Irina G.; Sarksian, Karen A.; Stepakhin, Vladimir D.; Skvortsova, Nina N.

    2016-01-01

    We introduce an approach toward the synthesis of micro- and nanostructures under nonequilibrium microwave discharges within metal-dielectric powder mixtures induced by powerful microwave gyrotron radiation. A new plasma-chemical reactor capable of sustaining a discharge regime with an afterglow phase of an order of magnitude longer than the gyrotron pulse duration was constructed for these experiments. In the nonequilibrium conditions of such a discharge, plasma-induced exothermic chemical reactions leading to the synthesis of various compounds were initiated. The synthesized structures were deposited on the reactor walls and on the impurity particles within the reactor. This method was tested under gyrotron-initiated discharges within various metal-dielectric powder mixtures of titanium-boron, molybdenum-boron, titanium-silicon-boron, molybdenum-boron nitride, molybdenum-tungsten-boron nitride, and so on. Depending on the powder mixture composition, reactor atmosphere, and other parameters, micro- and nanosized particles of boron nitride, titanium diboride, molybdenum boride, titanium boride, molybdenum, and molybdenum oxide, were synthesized, detected, and analyzed.

  2. 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.

  3. 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

  4. 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....

  5. 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.

  6. 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 ...

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Simultaneous Stabilization of Gyrotron Frequency and Power by PID Double Feedback Control on the Acceleration and Anode Voltages

    Science.gov (United States)

    Khutoryan, E. M.; Idehara, T.; Kuleshov, A. N.; Tatematsu, Y.; Yamaguchi, Y.; Matsuki, Y.; Fujiwara, T.

    2017-07-01

    In this paper, we present the results of simultaneous stabilization of both the frequency and the output power by a double PID feedback control on the acceleration and anode voltages in the 460-GHz gyrotron FU CW GVI, also known as "Gyrotron FU CW GO-1" (according to the nomenclature adopted at Osaka University). The approach used in the experiments is based on the modulation of the cyclotron frequency and the pitch factor (velocity ratio) of the electron beam by varying the acceleration and the anode voltages, respectively. In a long-term experiment, the frequency and power stabilities were made to be better than ±10-6 and ±1%, respectively.

  14. 3-D Printed High Power Microwave Magnetrons

    Science.gov (United States)

    Jordan, Nicholas; Greening, Geoffrey; Exelby, Steven; Gilgenbach, Ronald; Lau, Y. Y.; Hoff, Brad

    2015-11-01

    The size, weight, and power requirements of HPM systems are critical constraints on their viability, and can potentially be improved through the use of additive manufacturing techniques, which are rapidly increasing in capability and affordability. Recent experiments on the UM Recirculating Planar Magnetron (RPM), have explored the use of 3-D printed components in a HPM system. The system was driven by MELBA-C, a Marx-Abramyan system which delivers a -300 kV voltage pulse for 0.3-1.0 us, with a 0.15-0.3 T axial magnetic field applied by a pair of electromagnets. Anode blocks were printed from Water Shed XC 11122 photopolymer using a stereolithography process, and prepared with either a spray-coated or electroplated finish. Both manufacturing processes were compared against baseline data for a machined aluminum anode, noting any differences in power output, oscillation frequency, and mode stability. Evolution and durability of the 3-D printed structures were noted both visually and by tracking vacuum inventories via a residual gas analyzer. Research supported by AFOSR (grant #FA9550-15-1-0097) and AFRL.

  15. 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.

  16. Design of a system for conversion of gyrotron output into a gaussian beam

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, I. [Faculty of Engineering, Fukui Univ., Fukui (Japan); Idehara, T.; Sabchevski, S.; Glyavin, M.; Mitsudo, S. [Research Center for Development of Far-Infrared Region, Fukui Univ., Fukui (Japan); Sato, M.; Kawahata, K. [National Inst. for Fusion Science, Toki, Gifu (Japan); Brand, G.F. [School of Physics, Univ. of Sydney, NSW (Australia)

    2000-03-01

    A quasi-optical system consisting of a quasi-optical antenna, two ellipsoidal mirrors and a filter to block sidelobes can convert four TE{sub 1n} mode outputs of the Gyrotron FU IVA into gaussian-like beams with waist size of 16.3 mm. This system can convert three TE{sub 0n} mode outputs into bigaussian-like beams with waist size of 23.5 mm in width and 16.4 mm in length. (author)

  17. Coupler for coupling gyrotron whispering gallery mode RF into HE11 waveguide

    Science.gov (United States)

    Neilson, Jeffrey M

    2015-02-24

    A cylindrical waveguide with a mode converter transforms a whispering gallery mode from a gyrotron cylindrical waveguide with a helical cut launch edge to a quasi-Gaussian beam suitable for conveyance through a corrugated waveguide. This quasi-Gaussian beam is radiated away from the waveguide using a spiral cut launch edge, which is in close proximity to a first mode converting reflector. The first mode converting reflector is coupled to a second mode converting reflector which provides an output free-space HE11 mode wave suitable for direct coupling into a corrugated waveguide. The radiated beam produced at the output of the second mode converting reflector is substantially circular.

  18. Gyrotron Output Power Stabilization by PID Feedback Control of Heater Current and Anode Voltage

    Science.gov (United States)

    Khutoryan, E. M.; Idehara, T.; Kuleshov, A. N.; Ueda, K.

    2014-12-01

    To provide stable output power of a gyrotron during long operation time the power stabilization was achieved by two schemes with PID feedback control of heater current and anode voltage. It was based on the dependence of the output power on both the anode voltage and the beam current and also on the dependence of the beam current on the gun heater current. Both schemes provided decrease of the power standard deviation to 0.3-0.5%. The comparison between parameters of both schemes is discussed in the paper.

  19. 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.

  20. Neurodynamic oscillators

    Science.gov (United States)

    Espinosa, Ismael; Gonzalez, Hortensia; Quiza, Jorge; Gonazalez, J. Jesus; Arroyo, Ruben; Lara, Ritaluz

    1995-01-01

    Oscillation of electrical activity has been found in many nervous systems, from invertebrates to vertebrates including man. There exists experimental evidence of very simple circuits with the capability of oscillation. Neurons with intrinsic oscillation have been found and also neural circuits where oscillation is a property of the network. These two types of oscillations coexist in many instances. It is nowadays hypothesized that behind synchronization and oscillation there is a system of coupled oscillators responsible for activities that range from locomotion and feature binding in vision to control of sleep and circadian rhythms. The huge knowledge that has been acquired on oscillators from the times of Lord Rayleigh has made the simulation of neural oscillators a very active endeavor. This has been enhanced with more recent physiological findings about small neural circuits by means of intracellular and extracellular recordings as well as imaging methods. The future of this interdisciplinary field looks very promising; some researchers are going into quantum mechanics with the idea of trying to provide a quantum description of the brain. In this work we describe some simulations using neuron models by means of which we form simple neural networks that have the capability of oscillation. We analyze the oscillatory activity with root locus method, cross-correlation histograms, and phase planes. In the more complicated neural network models there is the possibility of chaotic oscillatory activity and we study that by means of Lyapunov exponents. The companion paper shows an example of that kind.

  1. Near Real-Time Gyrotron Data Streaming and Data Acquisition with ns Resolution on the DIII-D ECH System

    Science.gov (United States)

    Torrezan, A. C.; Ponce, D.; Gorelov, Y. A.; Cengher, M.; Lohr, J.

    2014-10-01

    As part of the expansion and upgrade of the electron cyclotron heating (ECH) systen on DIII-D, a new data acquisition setup has been implemented to acquire and display waveform data from all gyrotrons in near real time with high time resolution. The data acquisition for each gyrotron system is based on a fast digitizer with 8 channels running at 2 MS/s/channel and a resolution of 14 bits. This enables the operator to monitor all gyrotron-relevant variables as well as fast diagnostic signals such as window arcs. The data are transferred to a local computer through a 132 MB/s PCI bus, and then are streamed to the ECH operator and to a local network attached storage using 1 GB Ethernet links. The data are displayed to the ECH operator by means of a graphical user interface developed in LabVIEW, replacing physical scopes. Acquired gyrotron data are accessible at DIII-D through a local database (PTDATA) connected to the ECH data acquisition system by an Ethernet line, a configuration that eliminates the need for legacy CAMAC hardware in the data link. Work supported by the US Department of Energy under DE-FC02-04ER54698.

  2. High energy dense ribbon beams and high harmonic gyrotron at millimeter wavelengths

    Science.gov (United States)

    Ferendeci, Altan M.

    1991-01-01

    The progress made on the ribbon (sheet) beams and the rectangular harmonic gyrotron is presented. A relativistic three dimensional electron gun simulation program, called 3-D TRAJ is completed. A 3-D general numerical Poisson solvers is included in the program to take into account the nonuniform electrode boundaries that are common to ribbon beam guns or that may be required for any other gun structure. A novel computer technique is developed to generate the complicated 3-D general boundary data file of the MIG type guns by using a bot-map technique. At the same time, a theoretical approach to the design of MIG type guns is also undertaken. The location and the shape of the cathode is determined from the various conservation equations. Using the laminar flow equations and Harker synthesis technique, the required anode shapes are then determined. Finally, the resulting electrode shapes are used in the simulation of the MIG-gun using the 3-D TRAJ program. Experimental set-up to test the various MIG type electron guns and the axially grooved rectangular gyrotron is close to being completed.

  3. Accurate identification of whispering gallery mode patterns of gyrotron with stabilized electro-optic imaging system

    Science.gov (United States)

    Lee, Ingeun; Sawant, Ashwini; Choe, Mun Seok; Lee, Dong-Joon; Choi, EunMi

    2018-01-01

    The precise field pattern measurement and analysis of a typical whispering gallery mode excited in a gyrotron are important to understand the interaction physics of the gyrotron. We precisely analyzed the characteristic of a whispering gallery mode, rotating TE6,2 mode, by a photonic-assisted W-band (75-110 GHz) electro-optic imaging measurement system. The whispering gallery mode in the W-band region diverges fast in free space as it propagates from the radiation port. Therefore, scanning the field patterns of a device-under-test should be performed as close as possible to identify the device's characteristics. We successfully accomplished visualizing highly accurate field patterns of a rotating and mixed whispering gallery mode based on the measured electric field magnitude and phase by using dual optical fiber-scale electro-optic (EO) probes. We observed the distorted fields when the typical open-ended waveguide and a general EO probe were used in the extremely near-field zone, whereas a very precise field was measured in a minimally invasive way by the proposed EO probe. The measured mode patterns were quantitatively analyzed by using a cross correlation function and a mode purity equation. This work promises a way to provide accurate electric field information in the generation of the whispering gallery mode in the millimeter and submillimeter regime.

  4. Quantum Oscillators

    CERN Document Server

    Blaise, Paul

    2011-01-01

    An invaluable reference for an overall but simple approach to the complexity of quantum mechanics viewed through quantum oscillators Quantum oscillators play a fundamental role in many areas of physics; for instance, in chemical physics with molecular normal modes, in solid state physics with phonons, and in quantum theory of light with photons. Quantum Oscillators is a timely and visionary book which presents these intricate topics, broadly covering the properties of quantum oscillators which are usually dispersed in the literature at varying levels of detail and often combined with other p

  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. 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 ...

  7. 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

  8. 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....

  9. The potential of the gyrotrons for development of the sub-terahertz and the terahertz frequency range - A review of novel and prospective applications

    Energy Technology Data Exchange (ETDEWEB)

    Idehara, T.; Saito, T.; Ogawa, I.; Mitsudo, S.; Tatematsu, Y. [Research Center for Development of Far Infrared Region, University of Fukui, 3-9-1 Bunkyo, 910-8507 Fukui (Japan); Sabchevski, S. [Research Center for Development of Far Infrared Region, University of Fukui, 3-9-1 Bunkyo, 910-8507 Fukui (Japan); Institute of Electronics of the Bulgarian Academy of Sciences, 72 Tzarigradsko Shose Blvd., 1784 Sofia (Bulgaria)], E-mail: sabch@ie.bas.bg

    2008-12-31

    Some recent advancements in the development of powerful high frequency gyrotrons that generate coherent radiation in the sub-terahertz and terahertz regions of the electromagnetic spectrum as well as their typical and novel applications are presented and discussed.

  10. 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

  11. Chemical Oscillations

    Indian Academy of Sciences (India)

    processes at the cellular level like the glycolytic pathway, peroxi- dase-catalysed reaction or the biosynthesis of certain proteins. A systematic study of oscillating chemical reactions is of consider- able interest, since these oscillating reactions can be used as prototype examples of the behaviours possible in reactions gov-.

  12. High power microwave source with a three dimensional printed metamaterial slow-wave structure

    Energy Technology Data Exchange (ETDEWEB)

    French, David M.; Shiffler, Don [Air Force Research Laboratory, Directed Energy Directorate, Albuquerque, New Mexico 871117 (United States)

    2016-05-15

    For over the last decade, the concept of metamaterials has led to new approaches for considering the interaction of radiation with complex structures. However, practical manifestations of such a device operating at high power densities have proven difficult to achieve due to the resonant nature of metamaterials and the resultant high electric fields, which place severe constraints on manufacturing the slow wave structures. In this paper, we describe the first experimental manifestation of a high power microwave device utilizing a metallic slow wave structure (metamaterial-like) fabricated using additive manufacturing. The feasibility of utilizing additive manufacturing as a technique for building these relatively complicated structures has thus been demonstrated. The MW class microwave source operates in the C-band and shows frequency tunablility with electron beam voltage. The basic electromagnetic characteristics of this device, the construction using additive manufacturing, and the basic performance as a microwave oscillator are considered. Due to the tunable nature of the device, it shows promise not only as an oscillator but also as a microwave amplifier. Therefore, the dispersive characteristics and a discussion of the anticipated gain is included as it relates to an amplifier configuration.

  13. High power microwave source with a three dimensional printed metamaterial slow-wave structure.

    Science.gov (United States)

    French, David M; Shiffler, Don

    2016-05-01

    For over the last decade, the concept of metamaterials has led to new approaches for considering the interaction of radiation with complex structures. However, practical manifestations of such a device operating at high power densities have proven difficult to achieve due to the resonant nature of metamaterials and the resultant high electric fields, which place severe constraints on manufacturing the slow wave structures. In this paper, we describe the first experimental manifestation of a high power microwave device utilizing a metallic slow wave structure (metamaterial-like) fabricated using additive manufacturing. The feasibility of utilizing additive manufacturing as a technique for building these relatively complicated structures has thus been demonstrated. The MW class microwave source operates in the C-band and shows frequency tunablility with electron beam voltage. The basic electromagnetic characteristics of this device, the construction using additive manufacturing, and the basic performance as a microwave oscillator are considered. Due to the tunable nature of the device, it shows promise not only as an oscillator but also as a microwave amplifier. Therefore, the dispersive characteristics and a discussion of the anticipated gain is included as it relates to an amplifier configuration.

  14. 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.

  15. 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...

  16. 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...

  17. 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...

  18. 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.

  19. 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.

  20. 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...

  1. 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.

  2. 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.

  3. 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.

  4. 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....

  5. Fibonacci oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Arik, M. (Istanbul Technical Univ. (Turkey). Dept. of Mathematics Bogazici Univ., Istanbul (Turkey). Dept. of Physics); Demircan, E.; Turgut, T. (Texas Univ., Austin, TX (United States). Dept. of Physics); Ekinci, L.; Mungan, M. (Bogazici Univ., Istanbul (Turkey). Dept. of Physics)

    1992-07-01

    We discuss the properties of oscillators whose spectrum is given by a generalized Fibonacci sequence. The properties include: Invariance under the unitary quantum group, generalized angular momentum, coherent states and difference calculus, relativistic interpretation. (orig.).

  6. The Electron-Optical System of a Gyrotron with an Operating Frequency of 263 GHz for Spectroscopic Research

    Science.gov (United States)

    Kuftin, A. N.; Manuilov, V. N.

    2016-07-01

    We describe specific features of modeling numerically the operation of magnetron-injection guns, which form high-quality helical electron beams in gyrotrons operated in the short-wave part of the millimeter-wave band (at a wavelength of 1 mm). As an example, we consider the gun of a gyrotron having an operating frequency of 263 GHz designed for spectroscopic research. It is shown that there are good reasons to perform calculations and optimization of the magnetroninjection un in two steps. At the first step, a simplest two-dimensional model can be used, which allows only for the influence of the field of the electrodes and the intrinsic space charge of the beam on the beam parameters. At the second, final stage one should allow for such factors as roughness of the emitting surface and thermal velocities of electrons. The electron distribution function in oscillatory velocities and the coefficient of electron reflection from the magnetic mirror should be calculated. It is demonstrated that the magnetron-injection gun, which is optimized by the method presented, is sufficiently universal and can be operated both at the first and second cyclotron-frequency harmonics. This opens up the possibility of developing gyrotrons for spectroscopy applications at frequencies of 263 and 526 GHz, respectively, which are required for biological and medical research.

  7. 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.

  8. Prominence Oscillations

    Directory of Open Access Journals (Sweden)

    Iñigo Arregui

    2012-04-01

    Full Text Available Prominences are intriguing, but poorly understood, magnetic structures of the solar corona. The dynamics of solar prominences has been the subject of a large number of studies, and of particular interest is the study of prominence oscillations. Ground- and space-based observations have confirmed the presence of oscillatory motions in prominences and they have been interpreted in terms of magnetohydrodynamic (MHD waves. This interpretation opens the door to perform prominence seismology, whose main aim is to determine physical parameters in magnetic and plasma structures (prominences that are difficult to measure by direct means. Here, we review the observational information gathered about prominence oscillations as well as the theoretical models developed to interpret small amplitude oscillations and their temporal and spatial attenuation. Finally, several prominence seismology applications are presented.

  9. 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.

  10. 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.

  11. 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...

  12. 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.

  13. Chromosperic oscillations

    NARCIS (Netherlands)

    Rutten, R.J.

    1999-01-01

    This review concentrates on the quiet-Sun chromosphere. Its internetwork areas are dynamically dominated by the so-called chromospheric three-minute oscillation. They are interpretationally dominated by the so-called Ca II K 2V and H 2V grains. The main points of this review are that the one

  14. Toward High-Power Klystrons With RF Power Conversion Efficiency on the Order of 90%

    CERN Document Server

    Baikov, Andrey Yu; Syratchev, Igor

    2015-01-01

    The increase in efficiency of RF power generation for future large accelerators is considered a high priority issue. The vast majority of the existing commercial high-power RF klystrons operates in the electronic efficiency range between 40% and 55%. Only a few klystrons available on the market are capable of operating with 65% efficiency or above. In this paper, a new method to achieve 90% RF power conversion efficiency in a klystron amplifier is presented. The essential part of this method is a new bunching technique - bunching with bunch core oscillations. Computer simulations confirm that the RF production efficiency above 90% can be reached with this new bunching method. The results of a preliminary study of an L-band, 20-MW peak RF power multibeam klystron for Compact Linear Collider with the efficiency above 85% are presented.

  15. 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...

  16. High-power thulium fiber laser Q switched with single-layer graphene.

    Science.gov (United States)

    Tang, Yulong; Yu, Xuechao; Li, Xiaohui; Yan, Zhiyu; Wang, Qi Jie

    2014-02-01

    We report high-power 2 μm Tm3+ fiber lasers passively Q switched by double-piece single-layer graphene transferred onto a glass plate. Through manipulating intracavity laser beam size and increasing pump ratios, an average power of 5.2 W is directly achieved from the laser oscillator with an optical-to-optical slope efficiency of 26%. The laser pulse energy can be as high as ∼18  μJ, comparable to that from actively Q-switched fiber lasers. The narrowest pulse width is 320 ns, and the pulse repetition rate can be tuned from tens of kilohertz to 280 kHz by changing the pump power. To the best of our knowledge, this is the highest average power and pulse energy, as well as the narrowest pulse width, from graphene-based Q-switched 2 μm fiber lasers.

  17. Towards the optimization of the thermal–hydraulic performance of gyrotron collectors

    Energy Technology Data Exchange (ETDEWEB)

    Savoldi, Laura; Bertani, Cristina [Dipartimento Energia, Politecnico di Torino, 10129 Torino (Italy); Cau, Francesca; Cismondi, Fabio [F4E, Barcelona (Spain); Gantenbein, Gerd; Illy, Stefan [Karlsruhe Institute of Technology (KIT), Institute for Pulsed Power and Microwave Technology (IHM), Kaiserstr. 12, 76131 Karlsruhe (Germany); Monni, Grazia [Dipartimento Energia, Politecnico di Torino, 10129 Torino (Italy); Rozier, Yoann [Thales Electron Devices, 78141 Vélizy-Villacoublay (France); Zanino, Roberto, E-mail: roberto.zanino@polito.it [Dipartimento Energia, Politecnico di Torino, 10129 Torino (Italy)

    2015-11-15

    Different configurations of water-cooled Cu collector for gyrotrons are investigated using the StarCCM + CFD code, aimed at optimizing its thermal–hydraulic (TH) performance. Although the current collectors show a good performance, the collector can be subjected to transient heat loads, due to the spent electron beam, of up to several tens of MW/m{sup 2}, and there is an interest to increase the gyrotron output power in the future. Furthermore, an optimized cooling will lead to improved reliability and lifetime of the collector. Starting from a hypervapotron (HV)-like collector, characterized by 100+ deep rectangular cavities with aspect ratio (AR) = 3, we present in the first part of the paper a single-cavity steady-state parametric analysis of the effect of AR on the heat exhaust capabilities. The investigation is then extended to other collector designs, including circumferential ribs and dimples, in order to assess the options for further improvements of the TH performance. The peak Cu temperature is computed by the code and its minimization is the target of the present optimization exercise. A self-consistent estimate of the heat transfer coefficient between collector and coolant is also obtained, which could be useful for fatigue and lifetime assessments. In the second part of the paper the most promising collector geometries identified in the first part are analyzed in the case of a transient heat load (vertical sweeping), first at the level of a single spatial period of the collector structure, then at the full-collector level. The results of the TH transient analysis are compared with both the results of the first part and with the transient purely thermal analysis of the full collector, showing for all geometries considered in this study a room for cooling efficiency improvement with respect to the HV-like design with AR = 3, at least in the operating conditions considered for this study (V ∼ 4 m/s, almost 100 °C sub-cooling).

  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. 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

  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. 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.

  2. 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 ...

  3. 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.

  4. 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

  5. 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 ...

  6. 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.

  7. 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

  8. 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.

  9. 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 ...

  10. 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...

  11. 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.

  12. Cherenkov-cyclotron instability in a metamaterial loaded waveguide for high power generation

    Science.gov (United States)

    Lu, Xueying; Shapiro, Michael; Temkin, Richard

    2017-10-01

    This work presents the analytical theory for an S-band high power microwave experiment at MIT utilizing a metamaterial (MTM) structure. A 490 kV, 84 A electron beam travels through a rectangular waveguide loaded with two MTM plates in a DC magnetic field B0. The excited waveguide mode is deflecting with a transverse E field on beam axis. Microsecond long megawatt level microwave pulses were generated under a low B0 in the Cherenkov-cyclotron type of interaction. A linear theory has been developed to explain the high power generation due to the Cherenkov-cyclotron instability. The simplified model is a planar waveguide filled with a double negative dispersive medium, and in the mode being studied, the longitudinal E field has an antisymmetric pattern in the direction perpendicular to the MTM plates. We have proved that the Cherenkov-cyclotron instability can happen with a zero initial transverse beam velocity when B0 is below a threshold. Also this instability is a unique feature of the left-handed MTM, since it requires a propagating mode below the cut-off frequency. The minimum beam current to start the instability is calculated, and the scaling law different from that of the traditional backward wave oscillators operated by longitudinal bunching will be discussed. This research was supported by the Air Force Office of Scientific Research within the Multidisciplinary University Research Initiative under Grant No. FA9550-12-1-0489 through the University of New Mexico.

  13. Regime dependence of photo-darkening-induced modal degradation in high power fiber amplifier (Conference Presentation)

    Science.gov (United States)

    Boullet, Johan; Vincont, Cyril; Jolly, Alain; Pierre, Christophe

    2017-03-01

    Thermally induced transverse modal instabilities (TMI) have attracted these five years an intense research efforts of the entire fiber laser development community, as it represents the current most limiting effect of further power scaling of high power fiber laser. Anyway, since 2014, a few publications point out a new limiting thermal effect: fiber modal degradation (FMD). It is characterized by a power rollover and simultaneous increase of the cladding light at an average power far from the TMI threshold together with a degraded beam which does not exhibit temporal fluctuations, which is one of the main characteristic of TMI. We report here on the first systemic experimental study of FMD in a high power photonic crystal fiber. We put a particular emphasis on the dependence of its average power threshold on the regime of operation. We experimentally demonstrate that this dependence is intrinsically linked to regime-dependent PD-saturated losses, which are nearly three times higher in CW regime than in short pulse picosecond regime. We make the hypothesis that the existence of these different PD equilibrium states between CW regime and picosecond QCW pulsed regime is due to a partial photo-bleaching of color centers in picosecond regime thanks to a higher probability of multi-photon process induced photobleaching (PB) at high peak power. This hypothesis is corroborated by the demonstration of the reversibility of the FMD induced in CW regime by simply switching the seed CW 1064 nm light by a short pulse, picosecond oscillator.

  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. Intense high-frequency gyrotron-based microwave beams for material processing

    Energy Technology Data Exchange (ETDEWEB)

    Hardek, T.W.; Cooke, W.D.; Katz, J.D.; Perry, W.L.; Rees, D.E.

    1997-03-01

    Microwave processing of materials has traditionally utilized frequencies in the 0.915 and 2.45 GHz regions. Microwave power sources are readily available at these frequencies but the relatively long wavelengths can present challenges in uniformly heating materials. An additional difficulty is the poor coupling of ceramic based materials to the microwave energy. Los Alamos National Laboratory scientists, working in conjunction with the National Center for Manufacturing Sciences (NCMS), have assembled a high-frequency demonstration processing facility utilizing gyrotron based RF sources. The facility is primarily intended to demonstrate the unique features available at frequencies as high as 84 GHz. The authors can readily provide quasi-optical, 37 GHz beams at continuous wave (CW) power levels in the 10 kW range. They have also provided beams at 84 GHz at 10 kW CW power levels. They are presently preparing a facility to demonstrate the sintering of ceramics at 30 GHz. This paper presents an overview of the present demonstration processing facility and describes some of the features they have available now and will have available in the near future.

  16. Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Skalyga, V., E-mail: skalyga.vadim@gmail.com [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Izotov, I.; Golubev, S.; Razin, S. [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Sidorov, A. [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Maslennikova, A. [Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Nizhny Novgorod State Medical Academy, 10/1 Minina Sq., 603005 Nizhny Novgorod (Russian Federation); Volovecky, A. [Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Kalvas, T.; Koivisto, H.; Tarvainen, O. [University of Jyvaskyla, Department of Physics, PO Box 35 (YFL), 40500 Jyväskylä (Finland)

    2014-12-21

    Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D–D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm{sup 2} is demonstrated. Estimations based on obtained experimental results show that neutron target bombarded by such deuteron beams would theoretically yield a neutron flux density up to 6·10{sup 10} cm{sup −2}/s. Thus, neutron generator based on a high-current deuteron ECR source with a powerful plasma heating by gyrotron radiation could fulfill the BNCT requirements significantly lower price, smaller size and ease of operation in comparison with existing reactors and accelerators.

  17. FEL Oscillators

    Energy Technology Data Exchange (ETDEWEB)

    George Neil

    2003-05-12

    FEL Oscillators have been around since 1977 providing not only a test bed for the physics of Free Electron Lasers and electron/photon interactions but as a workhorse of scientific research. More than 30 FEL oscillators are presently operating around the world spanning a wavelength range from the mm region to the ultraviolet using DC and rf linear accelerators and storage rings as electron sources. The characteristics that have driven the development of these sources are the desire for high peak and average power, high micropulse energies, wavelength tunability, timing flexibility, and wavelengths that are unavailable from more conventional laser sources. Substantial user programs have been performed using such sources encompassing medicine, biology, solid state research, atomic and molecular physics, effects of non-linear fields, surface science, polymer science, pulsed laser vapor deposition, to name just a few.

  18. High-power broadband plasma maser with magnetic self-insulation

    Science.gov (United States)

    Litvin, Vitaliy O.; Loza, Oleg T.

    2018-01-01

    Presented in this paper are the results of a particle-in-cell modelling of a novel high-power microwave (HPM) source which combines the properties of two devices. The first prototype is a magnetically insulated transmission line oscillator (MILO), an HPM self-oscillator which does not need an external magnetic field and irradiates a narrow spectrum depending on its iris-loaded slow-wave structure. The second prototype is a plasma maser, a Cherenkov HPM amplifier driven by a high-current relativistic electron beam propagating in a strong external magnetic field in plasma which acts as a slow-wave structure. The radiation frequency of plasma masers mainly depends on an easily variable plasma concentration; hence, their spectrum may overlap a few octaves. The plasma-based HPM device described in this paper operates without an external magnetic field: it looks like an MILO in which the iris-loaded slow-wave structure is substituted by a hollow plasma tube. The small pulse duration of ˜1.5 ns prevents a feedback rise in the 20-cm long generation section so that the device operates as a noise amplifier. Unlike conventional ultra wideband generators, the spectrum depends not only on the pulse duration but mainly on plasma, so the operation frequency of the device ranges within 12 GHz. For irradiated frequencies above 2 GHz, the total pulse energy efficiency of 7% is demonstrated at the HPM power level ˜1 GW.

  19. 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.

  20. 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.

  1. 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....

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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....

  9. 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...

  10. 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.

  11. 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.

  12. 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.

  13. 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).

  14. 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.

  15. 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....

  16. Damage characteristics of the optical element in resonant cavity irradiated by high-power continuous-wave laser

    Science.gov (United States)

    Lou, Zhaokai; Han, Kai; Song, Rui; Yan, Baozhu; Liu, Zejin

    2017-05-01

    In order to study the damage characteristic of the contaminated resonating mirror in high power continuous wave (cw) laser system, we established a theoretical model based on the optical transmission theory with a gain medium. The optical propagation in the cavity is calculated utilizing a Fast Fourier Transform (FFT) repeatedly until the convergence of the calculations tend to a steady-state oscillation mode pattern. The influence of the contaminant size, the contaminant number and the cavity structure on the damage characteristic of the resonating mirror is studied in the theoretical model.

  17. 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.

  18. 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.

  19. Oscillators and Eigenvalues

    DEFF Research Database (Denmark)

    Lindberg, Erik

    1997-01-01

    In order to obtain insight in the nature of nonlinear oscillators the eigenvalues of the linearized Jacobian of the differential equations describing the oscillator are found and displayed as functions of time. A number of oscillators are studied including Dewey's oscillator (piecewise linear wit...... with negative resistance), Kennedy's Colpitts-oscillator (with and without chaos) and a new 4'th order oscillator with hyper-chaos.......In order to obtain insight in the nature of nonlinear oscillators the eigenvalues of the linearized Jacobian of the differential equations describing the oscillator are found and displayed as functions of time. A number of oscillators are studied including Dewey's oscillator (piecewise linear...

  20. Design of a Quasi-Optical System to Convert TE0n Mode Outputs of a Gyrotron into Gaussian Beams

    OpenAIRE

    Ogawa, I.; Yamada, Y; IDEHARA, T; SABCHEVSKI, S; Kasparek, W.

    2000-01-01

    In this paper we present a novel design of a quasi-optical system for conversion of gyrotron outputs into gaussian beams. It consists of a quasi-optical antenna, four focusing mirrors (parabolic cylinders) and a filter which removes the side lobes of the beam. The system is capable to convert three TE_0n mode outputs into gaussian beams with waist size of 16.7 mm as well as four TE_1n mode outputs into bi-gaussian beams with waist size of 10.9 mm in width and 16.5 mm in length.

  1. Oscillator circuits

    CERN Document Server

    Graf, Rudolf F

    1996-01-01

    This series of circuits provides designers with a quick source for oscillator circuits. Why waste time paging through huge encyclopedias when you can choose the topic you need and select any of the specialized circuits sorted by application?This book in the series has 250-300 practical, ready-to-use circuit designs, with schematics and brief explanations of circuit operation. The original source for each circuit is listed in an appendix, making it easy to obtain additional information.Ready-to-use circuits.Grouped by application for easy look-up.Circuit source listing

  2. Power oscillation damping controller

    DEFF Research Database (Denmark)

    2012-01-01

    A power oscillation damping controller is provided for a power generation device such as a wind turbine device. The power oscillation damping controller receives an oscillation indicating signal indicative of a power oscillation in an electricity network and provides an oscillation damping control...... signal in response to the oscillation indicating signal, by processing the oscillation damping control signal in a signal processing chain. The signal processing chain includes a filter configured for passing only signals within a predetermined frequency range....

  3. First and second harmonic ECRH experience at gyrotron frequencies at LLNL

    Energy Technology Data Exchange (ETDEWEB)

    Stallard, B.

    1987-11-01

    Plasma heating of electrons in both mirror machines and tokamaks, using mm wave gyrotron sources, have been carried out in many experiments in recent years. The technology for both sources and mode-preserving waveguide transmission systems is well developed at power levels of 200 kW. At LLNL electron heating at 28 GHz in the TMX-U tandem mirror has been used to create hot electrons required for a thermal barrier (potential well). TMX-U, and other devices operating at lower frequency and power (10 GHz, few kW), routinely generates electron populations with mean energies of 100 to 500 keV and densities in the low to mid 10/sup 11/ cm/sup -3/ range. Radial pressure profiles vary from peaked-on-axis to hollow and are dependent on the mod-B resonance surfaces. Experiments on the axisymmetric mirror SM-1 have shown improved heating efficiency using multiple frequencies with narrow frequency separation. The importance of rf diffusion in determining electron confinement has been shown in CONSTANCE B. Fokker-Planck and particle orbit models have been useful for understanding the importance of cavity heating for creating runaway electrons, the sensitivity of hot electron production to cold plasma, the reduction of electron lifetime by rf diffusion, and the effect of multiple frequencies on heating stochasticity. Potential wells generated in plasmas with large fractions of mirror-trapped electrons have been measured in TMX-U. These offer prospects for enhanced confinement of highly stripped ions. 11 refs., 18 figs., 2 tabs.

  4. 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.

  5. Three-Dimensional Numerical Simulation of a 30-GHz Gyrotron Resonator With an Explicit High-Order Discontinuous-Galerkin-Based Parallel Particle-In-Cell Method

    DEFF Research Database (Denmark)

    Stock, Andreas; Neudorfer, Jonathan; Riedlinger, Marc

    2012-01-01

    Fast design codes for the simulation of the particle–field interaction in the interior of gyrotron resonators are available. They procure their rapidity by making strong physical simplifications and approximations, which are not known to be valid for many variations of the geometry and the operat...

  6. Recent progress in the upgrade of the TCV EC-system with two 1MW/2s dual-frequency (84/126GHz) gyrotrons

    Science.gov (United States)

    Alberti, Stefano; Genoud, Jérémy; Goodman, Timothy; Hogge, Jean-Philippe; Porte, Laurie; Silva, Miguel; Tran, Trach-Minh; Tran, Minh-Quang; Avramidis, Konstantinos; Pagonakis, Ioannis; Jin, Jianbo; Illy, Stefan; Gantenbein, Gerd; Jelonnek, John; Thumm, Manfred; Bin, William; Bruschi, Alex; Garavaglia, Saul; Moro, Alessandro; Kasparek, Walter; Legrand, François; Perial, Etienne; Rozier, Yoan; Cismondi, Fabio; Doelman, Niek

    2017-10-01

    The upgrade of the EC-system of the TCV tokamak has entered in its realization phase and is part of a broader upgrade of TCV. The MW-class dual-frequency gyrotrons (84 or 126GHz/2s/1MW) are presently being manufactured by Thales Electron Devices with the first gyrotron foreseen to be delivered at SPC by the end of 2017. In parallel to the gyrotron development, for extending the level of operational flexibility of the TCV EC-system the integration of the dual-frequency gyrotrons adds a significant complexity in the evacuated 63.5mm-diameter HE11 transmission line system connected to the various TCV low-field side and top launchers. As discussed in [1], an important part of the present TCV-upgrade consists in inserting a modular closed divertor chamber. This will have an impact on the X3 top-launcher which will have to be reduced in size. For using the new compact launcher we are considering employing a Fast Directional Switch (FADIS), combining the two 1MW/126GHz/2s rf-beams into a single 2MW rf-beam.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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...

  15. 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.

  16. 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...

  17. 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.

  18. 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

  19. 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...

  20. 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.

  1. 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.

  2. 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.

  3. Demonstration of a High-Order Mode Input Coupler for a 220-GHz Confocal Gyrotron Traveling Wave Tube

    Science.gov (United States)

    Guan, Xiaotong; Fu, Wenjie; Yan, Yang

    2018-02-01

    A design of high-order mode input coupler for 220-GHz confocal gyrotron travelling wave tube is proposed, simulated, and demonstrated by experimental tests. This input coupler is designed to excite confocal TE 06 mode from rectangle waveguide TE 10 mode over a broadband frequency range. Simulation results predict that the optimized conversion loss is about 2.72 dB with a mode purity excess of 99%. Considering of the gyrotron interaction theory, an effective bandwidth of 5 GHz is obtained, in which the beam-wave coupling efficiency is higher than half of maximum. The field pattern under low power demonstrates that TE 06 mode is successfully excited in confocal waveguide at 220 GHz. Cold test results from the vector network analyzer perform good agreements with simulation results. Both simulation and experimental results illustrate that the reflection at input port S11 is sensitive to the perpendicular separation of two mirrors. It provides an engineering possibility for estimating the assembly precision.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  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 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.

  19. 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...

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

    High power proton accelerators allow providing, by spallation reaction, the neutron fluxes necessary in the synthesis of fissile material, starting from Uranium 238 or Thorium 232. This is the basis of the concept of sub-critical operation of a reactor, for energy production or nuclear waste transmutation, with the objective of achieving cleaner, safer and more efficient process than today’s technologies allow. Designing, building and operating a proton accelerator in the 500-1000 MeV energy range, CW regime, MW power class still remains a challenge nowadays. There is a limited number of installations at present achieving beam characteristics in that class, e.g., PSI in Villigen, 590 MeV CW beam from a cyclotron, SNS in Oakland, 1 GeV pulsed beam from a linear accelerator, in addition to projects as the ESS in Europe, a 5 MW beam from a linear accelerator. Furthermore, coupling an accelerator to a sub-critical nuclear reactor is a challenging proposition: some of the key issues/requirements are the design of a spallation target to withstand high power densities as well as ensure the safety of the installation. These two domains are the grounds of the PhD work: the focus is on the high power ring methods in the frame of the KURRI FFAG collaboration in Japan: upgrade of the installation towards high intensity is crucial to demonstrate the high beam power capability of FFAG. Thus, modeling of the beam dynamics and benchmarking of different codes was undertaken to validate the simulation results. Experimental results revealed some major losses that need to be understood and eventually overcome. By developing analytical models that account for the field defects, one identified major sources of imperfection in the design of scaling FFAG that explain the important tune variations resulting in the crossing of several betatron resonances. A new formula is derived to compute the tunes and properties established that characterize the effect of the field imperfections on the

  7. Generation of Acoustic Gravity Waves by Periodic Radio Transmissions from a High-Power Ionospheric Heater

    Science.gov (United States)

    Frolov, Vladimir; Chernogor, Leonid; Rozumenko, Victor

    The Radiophysical Research Institute (Nizhny Novgorod, Russia) and Kharkiv V. N. Karazin National University (Kharkiv, Ukraine) have studied opportunities for the effective generation of acoustic gravity waves (AGWs) in 3 - 180-min period range. The excitation of such waves was conducted for the last several years using the SURA heating facility (Nizhny Novgorod). The detection of the HF-induced AGWs was carried out in the Radiophysical Observatory located near Kharkiv City at a distance of about 960 km from the SURA. A coherent radar for vertical sounding, an ionosonde, and magnetometer chains were used in our measurements. The main results are the following (see [1-5]): 1. Infrasound oscillation trains with a period of 6 min are detected during periodic SURA heater turn-on and -off. Similar oscillation trains are detected after long time pumping, during periodic transmissions with a period of 20 s, as well as after pumping turn-off. The train recordings begin 28 - 54 min after the heater turn-on or -off, and the train propagation speeds are about 300 - 570 m/s, the value of which is close to the sound speed at upper atmospheric altitudes. The amplitude of the Doppler shift frequency is of 10 - 40 mHz, which fits to the 0.1 - 0.3% electron density disturbances at ionospheric altitudes. The amplitude of the infrasound oscillations depends on the SURA mode of operation and the state of the upper atmosphere and ionosphere. 2. High-power radio transmissions stimulate the generation (or enhancement) of waves at ionospheric altitudes in the range of internal gravity wave periods. The HF-induced waves propagate with speeds of 360 - 460 m/s and produce changes in electron density with amplitudes of 2 - 3%. The generation of such periodic perturbations is more preferable with periods of 10 - 60 minutes. Their features depend significantly on the heater mode of operation. It should be stressed that perturbation intensity increases when a pumping wave frequency approaches

  8. Self oscillating PWM modulators, a topological comparison

    DEFF Research Database (Denmark)

    Poulsen, Søren; Andersen, Michael Andreas E.

    2004-01-01

    's work with switch mode audio power amplifiers, where linear tracking of the reference signal is of major importance. Use of the modulator topologies presented are not limited to this kind of equipment, but can be used in a very wide range of applications from very low to very high power levels....... or fs/ð range respectively, where fs is the switching frequency of the converter. For some applications this will require unacceptable high switching frequency to achieve enough control loop bandwidth for the desired dynamic performance. With self oscillating modulators, the open loop bandwidth is equal...... or by shaping the open loop function of the modulator so its gain and phase response causes a closed loop natural oscillation. The two main types of self oscillating modulators have many similarities, but differences in dynamic performance and linearity are present. The work presented is related to the author...

  9. Plasma-filled rippled wall rectangular backward wave oscillator ...

    Indian Academy of Sciences (India)

    The backward wave oscillator is a device designed to efficiently convert the energy of an electron beam into electromagnetic radiation at microwave frequencies [1]. Emerging needs for high power and ... tions in carrying input power inside the slow wave structure and so the resultant power cannot be increased after some ...

  10. Development of a 2 MW relativistic backward wave oscillator

    Indian Academy of Sciences (India)

    In this paper, a high power relativistic backward wave oscillator (BWO) experiment is reported. A 230 keV, 2 kA, 150 ns relativistic electron beam is generated using a Marx generator. The beam is then injected into a hollow rippled wall metallic cylindrical tube that forms a slow wave structure. The beam is guided using an ...

  11. Research on Novel High-Power Microwave/Millimeter Wave Sources and Applications

    Science.gov (United States)

    2010-08-28

    theoretical support for the experiments at UC Davis aimed at the development of a zero-drive stable W-band gyrotron traveling-wave amplifier (Gyro- TWT ). The...this gyro- TWT ; namely, a new type of electron gun based on the robust, long-lived, clean, low work function, high current density thermionic cathodes...recently developed at UC Davis under the sponsorship of MURI-04. This is an electron gun to be used for the zero-drive stable Gyro- TWT . Our

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Mutual phase-locking of planar nano-oscillators

    Directory of Open Access Journals (Sweden)

    K. Y. Xu

    2014-06-01

    Full Text Available Characteristics of phase-locking between Gunn effect-based planar nano-oscillators are studied using an ensemble Monte Carlo (EMC method. Directly connecting two oscillators in close proximity, e.g. with a channel distance of 200 nm, only results in incoherent oscillations. In order to achieve in-phase oscillations, additional considerations must be taken into account. Two coupling paths are shown to exist between oscillators. One coupling path results in synchronization and the other results in anti-phase locking. The coupling strength through these two paths can be adjusted by changing the connections between oscillators. When two identical oscillators are in the anti-phase locking regime, fundamental components of oscillations are cancelled. The resulting output consists of purely second harmonic oscillations with a frequency of about 0.66 THz. This type of second harmonic generation is desired for higher frequency applications since no additional filter system is required. This transient phase-locking process is further analyzed using Adler's theory. The locking range is extracted, and a criterion for the channel length difference required for realizing phased arrays is obtained. This work should aid in designing nano-oscillator arrays for high power applications and developing directional transmitters for wireless communications.

  12. High power fiber laser system for a high repetition rate laserwire

    Directory of Open Access Journals (Sweden)

    L. J. Nevay

    2014-07-01

    Full Text Available We present the development of a high power fiber laser system to investigate its suitability for use in a transverse electron beam profile monitor, i.e., a laserwire. A system capable of producing individual pulses up to 165.8±0.4  μJ at 1036 nm with a full width at half maximum of 1.92±0.12  ps at 6.49 MHz is demonstrated using a master oscillator power amplifier design with a final amplification stage in a rod-type photonic crystal fiber. The pulses are produced in trains of 1 ms in a novel burst mode amplification scheme to match the bunch pattern of the charged particles in an accelerator. This method allows pulse energies up to an order of magnitude greater than the steady-state value of 17.0±0.6  μJ to be achieved at the beginning of the burst with a demonstrated peak power of 25.8±1.7  MW after compression. The system is also shown to demonstrate excellent spatial quality with an M^{2}=1.26±0.01 in both dimensions, which would allow nearly diffraction limited focusing to be achieved.

  13. All solid-state high power microwave source with high repetition frequency

    Science.gov (United States)

    Bragg, J.-W. B.; Sullivan, W. W.; Mauch, D.; Neuber, A. A.; Dickens, J. C.

    2013-05-01

    An all solid-state, megawatt-class high power microwave system featuring a silicon carbide (SiC) photoconductive semiconductor switch (PCSS) and a ferrimagnetic-based, coaxial nonlinear transmission line (NLTL) is presented. A 1.62 cm2, 50 kV 4H-SiC PCSS is hard-switched to produce electrical pulses with 7 ns full width-half max (FWHM) pulse widths at 2 ns risetimes in single shot and burst-mode operation. The PCSS resistance drops to sub-ohm when illuminated with approximately 3 mJ of laser energy at 355 nm (tripled Nd:YAG) in a single pulse. Utilizing a fiber optic based optical delivery system, a laser pulse train of four 7 ns (FWHM) signals was generated at 65 MHz repetition frequency. The resulting electrical pulse train from the PCSS closely follows the optical input and is utilized to feed the NLTL generating microwave pulses with a base microwave-frequency of about 2.1 GHz at 65 MHz pulse repetition frequency (prf). Under typical experimental conditions, the NLTL produces sharpened output risetimes of 120 ps and microwave oscillations at 2-4 GHz that are generated due to damped gyromagnetic precession of the ferrimagnetic material's axially pre-biased magnetic moments. The complete system is discussed in detail with its output matched into 50 Ω, and results covering MHz-prf in burst-mode operation as well as frequency agility in single shot operation are discussed.

  14. 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.

  15. 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...

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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 | .

  4. 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.

  5. 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...

  6. 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.

  7. 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...

  8. 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...

  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. 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.

  11. 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).

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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...

  17. 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.

  18. All solid-state high power visible laser

    Science.gov (United States)

    Grossman, William M.

    1993-01-01

    The overall objective of this Phase 2 effort was to develop and deliver to NASA a high repetition rate laser-diode-pumped solid-state pulsed laser system with output in the green portion of the spectrum. The laser is for use in data communications, and high efficiency, short pulses, and low timing jitter are important features. A short-pulse 1 micron laser oscillator, a new multi-pass amplifier to boost the infrared power, and a frequency doubler to take the amplified infrared pulsed laser light into the green. This produced 1.5 W of light in the visible at a pulse repetition rate of 20 kHz in the laboratory. The pulses have a full-width at half maximum of near 1 ns. The results of this program are being commercialized.

  19. Klystrons, traveling wave tubes, magnetrons, crossed-field amplifiers, and gyrotrons

    CERN Document Server

    Gilmour, A S

    2011-01-01

    Microwave tubes are vacuum electron devices used for the generation and amplification of radio frequencies in the microwave range. An established technology area, the use of tubes remains essential in the field today for high-power applications. The culmination of the author's 50 years of industry experience, this authoritative resource offers you a thorough understanding of the operations and major classes of microwave tubes.Minimizing the use of advanced mathematics, the book places emphasis on clear qualitative explanations of phenomena. This practical reference serves as an excellent intro

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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).

  8. 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.

  9. 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

  10. Generation of high-power terahertz radiation by nonlinear photon-assisted tunneling transport in plasmonic metamaterials

    Science.gov (United States)

    Chen, Pai-Yen; Salas, Rodolfo; Farhat, Mohamed

    2017-12-01

    We propose an optoelectronic terahertz oscillator based on the quantum tunneling effect in a plasmonic metamaterial, utilizing a nanostructured metal-insulator-metal (MIM) tunneling junction. The collective resonant response of meta-atoms can achieve >90% optical absorption and strongly localized optical fields within the MIM plasmonic nanojunction. By properly tailoring the radiation aperture, the nonlinear quantum conductance induced by the metamaterial-enhanced, photon-assisted tunneling may produce miliwatt-level terahertz radiation through the optical beating (or heterodyne down conversion) of two lasers with a slight frequency offset. We envisage that the interplay between photon-assisted tunneling and plasmon coupling within the MIM metamaterial/diode may substantially enhance the modulated terahertz photocurrent, and may therefore realize a practical high-power, room-temperature source in applications of terahertz electronics.

  11. High-power graphene mode-locked Tm/Ho co-doped fiber laser with evanescent field interaction.

    Science.gov (United States)

    Li, Xiaohui; Yu, Xuechao; Sun, Zhipei; Yan, Zhiyu; Sun, Biao; Cheng, Yuanbing; Yu, Xia; Zhang, Ying; Wang, Qi Jie

    2015-11-16

    Mid-infrared ultrafast fiber lasers are valuable for various applications, including chemical and biomedical sensing, material processing and military applications. Here, we report all-fiber high-power graphene mode-locked Tm/Ho co-doped fiber laser at long wavelength with evanescent field interaction. Ultrafast pulses up to 7.8 MHz are generated at a center wavelength of 1879.4 nm, with a pulse width of 4.7 ps. A graphene absorber integrated with a side-polished fiber can increase the damage threshold significantly. Harmonics mode-locking can be obtained till to the 21(th) harmonics at a pump power of above 500 mW. By using one stage amplifier in the anomalous dispersion regime, the laser can be amplified up to 450 mW and the narrowest pulse duration of 1.4 ps can be obtained simultaneously. Our work paves the way to graphene Tm/Ho co-doped mode-locked all-fiber master oscillator power amplifiers as potentially efficient and economic laser sources for high-power laser applications, such as special material processing and nonlinear optical studies.

  12. Microelectronic oscillator, 2

    Science.gov (United States)

    Kleinberg, L. L.

    1969-01-01

    Microelectronic oscillator uses a bipolar transistor to circumvent the problem of developing suitable inductors for lower frequencies. The oscillator is fabricated by hybrid thin film techniques or by monolithic construction. Discrete microminiature components may also be employed.

  13. Oscillating heat pipes

    CERN Document Server

    Ma, Hongbin

    2015-01-01

    This book presents the fundamental fluid flow and heat transfer principles occurring in oscillating heat pipes and also provides updated developments and recent innovations in research and applications of heat pipes. Starting with fundamental presentation of heat pipes, the focus is on oscillating motions and its heat transfer enhancement in a two-phase heat transfer system. The book covers thermodynamic analysis, interfacial phenomenon, thin film evaporation,  theoretical models of oscillating motion and heat transfer of single phase and two-phase flows, primary  factors affecting oscillating motions and heat transfer,  neutron imaging study of oscillating motions in an oscillating heat pipes, and nanofluid’s effect on the heat transfer performance in oscillating heat pipes.  The importance of thermally-excited oscillating motion combined with phase change heat transfer to a wide variety of applications is emphasized. This book is an essential resource and learning tool for senior undergraduate, gradua...

  14. Phenomenology of neutrino oscillations

    Indian Academy of Sciences (India)

    Abstract. The phenomenology of solar, atmospheric, supernova and laboratory neutrino oscillations is described. Analytical formulae for matter effects are reviewed. The results from oscillations are confronted with neutrinoless double beta decay.

  15. 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

  16. Room temperature high power frequency conversion in periodically poled quasi-phase-matched crystals

    Science.gov (United States)

    Katz, M.; Blau, P.; Shulga, B.

    2008-02-01

    Near-stoichiometric lithium tantalate (SLT) crystals were produced from congruent lithium tantalate by a vapor-transport equilibration (VTE) process. The VTE'ed SLT (VSLT) crystals exhibited very low coercive field of 60-120-V/mm and improved high intensity damage resistance. The ~603°C Curie temperature of the congruent raw material climbed to 693+/-0.1°C in the VSLT crystal regardless of the congruent crystal stoichiometric composition or of the exact VTE process temperature profile. Stable, high power near room temperature second harmonic generation (SHG) and optical parametric oscillation (OPO) were demonstrated with these crystals. SHG measurements of a 1064-nm pulsed laser were realized by an 8-μm period grating, 21-mm-long sample. With 29-ns long pulses at 20-kHz repetition rate, 7.3-W (average power), of 532-nm radiation was generated with 55% conversion efficiency. With 25-ns long pulses at 10-kHz repetition rate in the same sample, 6.3-W of average-power with 61% conversion efficiency was obtained. 1.41-W average-power, at 4.013-μm idler wavelength was generated in an OPO configuration. The 28.65-μm period grating, 24-mm-long sample, was pumped by 25-ns pulses, 10-kHz repetition rate, 1.064-μm Nd:YVO 4 laser. In addition to the original (intended) signal and idler wavelengths, 0.27-W was obtained at 4.686-μm idler wavelength, by a secondary OPO process which developed in the system. Primary and secondary OPO operation was also observed in a 27.15-μm period grating, 38-mm-long sample. 0.67-W at 4.48-μm and 0.15-W at 5.03-μm were generated in this experiment.

  17. Tutorial: Reactive high power impulse magnetron sputtering (R-HiPIMS)

    Science.gov (United States)

    Anders, André

    2017-05-01

    High Power Impulse Magnetron Sputtering (HiPIMS) is a coating technology that combines magnetron sputtering with pulsed power concepts. By applying power in pulses of high amplitude and a relatively low duty cycle, large fractions of sputtered atoms and near-target gases are ionized. In contrast to conventional magnetron sputtering, HiPIMS is characterized by self-sputtering or repeated gas recycling for high and low sputter yield materials, respectively, and both for most intermediate materials. The dense plasma in front of the target has the dual function of sustaining the discharge and providing plasma-assistance to film growth, affecting the microstructure of growing films. Many technologically interesting thin films are compound films, which are composed of one or more metals and a reactive gas, most often oxygen or nitrogen. When reactive gas is added, non-trivial consequences arise for the system because the target may become "poisoned," i.e., a compound layer forms on the target surface affecting the sputtering yield and the yield of secondary electron emission and thereby all other parameters. It is emphasized that the target state depends not only on the reactive gas' partial pressure (balanced via gas flow and pumping) but also on the ion flux to the target, which can be controlled by pulse parameters. This is a critical technological opportunity for reactive HiPIMS (R-HiPIMS). The scope of this tutorial is focused on plasma processes and mechanisms of operation and only briefly touches upon film properties. It introduces R-HiPIMS in a systematic, step-by-step approach by covering sputtering, magnetron sputtering, reactive magnetron sputtering, pulsed reactive magnetron sputtering, HiPIMS, and finally R-HiPIMS. The tutorial is concluded by considering variations of R-HiPIMS known as modulated pulsed power magnetron sputtering and deep-oscillation magnetron sputtering and combinations of R-HiPIMS with superimposed dc magnetron sputtering.

  18. The colpitts oscillator family

    DEFF Research Database (Denmark)

    Lindberg, Erik; Murali, K.; Tamasevicius, A.

    A tutorial study of the Colpitts oscillator family defined as all oscillators based on a nonlinear amplifier and a three- terminal linear resonance circuit with one coil and two capacitors. The original patents are investigated. The eigenvalues of the linearized Jacobian for oscillators based...

  19. Compact, high-power, high-beam-quality quasi-CW microsecond five-pass zigzag slab 1319  nm amplifier.

    Science.gov (United States)

    Guo, Chuan; Zuo, Junwei; Bian, Qi; Xu, Chang; Zong, Qinshuang; Bo, Yong; Shen, Yu; Zong, Nan; Gao, Hongwei; Lin, Yanyong; Yuan, Lei; Liu, Yang; Cui, Dafu; Peng, Qinjun; Xu, Zuyan

    2017-04-20

    We demonstrate a compact, high-power, quasi-continuous-wave (QCW) end-pumped 1319 nm Nd:YAG slab amplifier laser with good beam quality. The laser is based on a QCW pulse Nd:YAG master oscillator and Nd:YAG slab amplifier with multi-pass zigzag architecture. The amplifier operates at a pulse repetition frequency of 500 Hz and pulse width of ∼105  μs, delivering a maximum output power of 51.5 W under absorbed pump power of 217.8 W and corresponding to an extraction efficiency of 14.2%. The beam quality factor is measured to be Mx2=1.61 and My2=1.81 in the orthogonal directions. To the best of our knowledge, this is the first compact, high-power, high-beam-quality QCW Nd:YAG amplifier at 1319 nm based on a multi-pass zigzag slab structure.

  20. 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.

  1. 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.

  2. Nature's Autonomous Oscillators

    Science.gov (United States)

    Mayr, H. G.; Yee, J.-H.; Mayr, M.; Schnetzler, R.

    2012-01-01

    Nonlinearity is required to produce autonomous oscillations without external time dependent source, and an example is the pendulum clock. The escapement mechanism of the clock imparts an impulse for each swing direction, which keeps the pendulum oscillating at the resonance frequency. Among nature's observed autonomous oscillators, examples are the quasi-biennial oscillation and bimonthly oscillation of the Earth atmosphere, and the 22-year solar oscillation. The oscillations have been simulated in numerical models without external time dependent source, and in Section 2 we summarize the results. Specifically, we shall discuss the nonlinearities that are involved in generating the oscillations, and the processes that produce the periodicities. In biology, insects have flight muscles, which function autonomously with wing frequencies that far exceed the animals' neural capacity; Stretch-activation of muscle contraction is the mechanism that produces the high frequency oscillation of insect flight, discussed in Section 3. The same mechanism is also invoked to explain the functioning of the cardiac muscle. In Section 4, we present a tutorial review of the cardio-vascular system, heart anatomy, and muscle cell physiology, leading up to Starling's Law of the Heart, which supports our notion that the human heart is also a nonlinear oscillator. In Section 5, we offer a broad perspective of the tenuous links between the fluid dynamical oscillators and the human heart physiology.

  3. High-power ultralong-wavelength Tm-doped silica fiber laser cladding-pumped with a random distributed feedback fiber laser

    OpenAIRE

    Xiaoxi Jin; Xueyuan Du; Xiong Wang; Pu Zhou; Hanwei Zhang; Xiaolin Wang; Zejin Liu

    2016-01-01

    We demonstrated a high-power ultralong-wavelength Tm-doped silica fiber laser operating at 2153?nm with the output power exceeding 18?W and the slope efficiency of 25.5%. A random distributed feedback fiber laser with the center wavelength of 1173?nm was employed as pump source of Tm-doped fiber laser for the first time. No amplified spontaneous emissions or parasitic oscillations were observed when the maximum output power reached, which indicates that employing 1173?nm random distributed fe...

  4. Control of the Superconducting Magnets current Power Supplies of the TJ-II Gyrotrons; Control de las Fuentes de Corriente de las Bobinas Superconductoras de los Girotrones del TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Ros, A.; Fernandez, A.; Tolkachev, A.; Catalan, G.

    2006-07-01

    The TJ-II ECRH heating system consists of two gyrotrons, which can deliver a maximum power of 300 kW at a frequency of 53.2 GHz. Another 28 GHz gyrotron is going to be used in the Bernstein waves heating system. In order to get the required frequency, the gyrotrons need and homogeneous magnetic field of several tesla, which is generated by a superconducting coil field by a current source. This document describes the current source control as well as the high precision ammeters control. These ammeters measure the current in the superconducting coils. The user interface and the programming of the control system are described. The communication between devices is also explained. (author) 9 Refs.

  5. A memristor-based third-order oscillator: beyond oscillation

    Science.gov (United States)

    Talukdar, A.; Radwan, A. G.; Salama, K. N.

    2011-09-01

    This paper demonstrates the first third-order autonomous linear time variant circuit realization that enhances parametric oscillation through the usage of memristor in conventional oscillators. Although the output has sustained oscillation, the linear features of the conventional oscillators become time dependent. The poles oscillate in nonlinear behavior due to the oscillation of memristor resistance. The mathematical formulas as well as SPICE simulations are introduced for the memristor-based phase shift oscillator showing a great matching.

  6. A memristor-based third-order oscillator: beyond oscillation

    KAUST Repository

    Talukdar, Abdul Hafiz Ibne

    2012-10-06

    This paper demonstrates the first third-order autonomous linear time variant circuit realization that enhances parametric oscillation through the usage of memristor in conventional oscillators. Although the output has sustained oscillation, the linear features of the conventional oscillators become time dependent. The poles oscillate in nonlinear behavior due to the oscillation of memristor resistance. The mathematical formulas as well as SPICE simulations are introduced for the memristor-based phase shift oscillator showing a great matching.

  7. Towards the formulation of a realistic 3D model for simulation of magnetron injection guns for gyrotrons. A preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Sabchevski, S. [Bulgarian Academy of Sciences (Bulgaria). Institute of Electronics; Zhelyazkov, I. [Sofia Univ. (Bulgaria). Faculty of Physics; Illy, S.; Piosczyk, B.; Borie, E.

    2008-07-15

    Numerical experiments based on adequate, self-consistent physical models implemented in simulation codes are widely used for computer-aided design (CAD), analysis and optimization of the electron optical systems (EOS) of the gyrotrons. An essential part of the physical model is the emission model, i.e., the relations that govern the value of the beam current extracted from the emitter as well as its energy spectrum, spatial and angular distribution. In this paper, we present a compendium of the basic theory, the most essential formulas and discuss the most important factors responsible for the nonuniformity of the emission and velocity spread. We also review the emission models realized in various ray-tracing and Particle-In-Cell (PIC) codes and present a general formulation of a 3D emission model based on the principle of decomposition of the region near the cathode to a set of equivalent diodes. It is believed that the information summarized in this compendium will be helpful for the development of novel modules for calculation of the initial distribution in both the available 2D computer programs that are being upgraded now and in the novel 3D simulation tools development of which is in progress now. (orig.)

  8. Study of hydrogen ECR plasma in a simple mirror magnetic trap heated by 75 GHz pulsed gyrotron radiation

    Science.gov (United States)

    Skalyga, V. A.; Izotov, I. V.; Sidorov, A. V.; Golubev, S. V.; Razin, S. V.

    2017-03-01

    Plasma of electron cyclotron resonance (ECR) discharge sustained by millimeter wave radiation is widely used for production of ion beams of different kind. The main trend in ECR ion sources development nowadays is an increase of frequency and power of microwave heating. The most advanced systems use gyrotrons in 24-60 GHz frequency range. In previous studies at IAP RAS it was demonstrated that ECR source SMIS 37 (Simple Mirror Ion Source) with 37.5 GHz heating operating in quasigasdynamic regime of plasma confinement is able to produce proton and deuteron beams with ion current density about 700 mA/cm2. As the next step of these investigations plasma properties of the discharge sustained by 75 GHz radiation have been studied. Plasma density and electron temperature were determined using spectroscopic and Langmuir probe techniques. It was demonstrated that plasma density could reach values close to 1014 cm-3 and that is of great interest for further development of high current ion sources for various applications.

  9. Radial electron-beam-breakup transit-time oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Mostrom, M.A. [Mission Research Corp., Albuquerque, NM (United States); Kwan, T.J.T. [Los Alamos National Lab., NM (United States)

    1995-01-01

    A new radially-driven electron-beam-breakup transit-time oscillator has been investigated analytically and through computer simulation as a compact low-impedance high-power microwave generator. In a 1MV, 50kA device 35cm in radius and 15cm long, with no external magnetic field, 5GW of extracted power and a growth rate of 0.26/ns have been observed. Theoretical maximum efficiencies are several times higher.

  10. Overview on thermal and mechanical challenges of high power RF electronic packaging

    NARCIS (Netherlands)

    Yuan, C.A.; Kregting, R.; Driel, W. van; Gielen, A.W.J.; Xiao, A.; Zhang, G.Q.

    2011-01-01

    High Power RF electronics is one of the essential parts for wireless communication, including the personal communication, broadcasting, microwave radar, etc. Moreover, high efficient high power electronics has entered the ISM market, such as the power generator of microwave oven. Power electronics

  11. Collective Thomson scattering of a high power electron cyclotron resonance heating beam in LHD

    DEFF Research Database (Denmark)

    Kubo, S.; Nishiura, M.; Tanaka, K.

    2010-01-01

    Collective Thomson scattering (CTS) system has been constructed at LHD making use of the high power ECRH system in LHD. The necessary features for CTS, high power probing beams and receiving beams, both with well defined Gaussian profile and with the fine controllability, are endowed in the ECRH...

  12. Enhancing Plasma Surface Modification using high Intensity and high Power Ultrasonic Acoustic Waves

    DEFF Research Database (Denmark)

    2010-01-01

    high intensity and high power acoustic waves (102) by at least one ultrasonic high intensity and high power acoustic wave generator (101 ), wherein the ultrasonic acoustic waves are directed to propagate towards said surface (314) of the object (100) so that a laminar boundary layer (313) of a gas...

  13. Systems and assemblies for transferring high power laser energy through a rotating junction

    Science.gov (United States)

    Norton, Ryan J.; McKay, Ryan P.; Fraze, Jason D.; Rinzler, Charles C.; Grubb, Daryl L.; Faircloth, Brian O.; Zediker, Mark S.

    2016-01-26

    There are provided high power laser devices and systems for transmitting a high power laser beam across a rotating assembly, including optical slip rings and optical rotational coupling assemblies. These devices can transmit the laser beam through the rotation zone in free space or within a fiber.

  14. High-power picosecond pulse delivery through hollow core photonic band gap fibers

    DEFF Research Database (Denmark)

    Michieletto, Mattia; Johansen, Mette Marie; Lyngsø, Jens Kristian

    2015-01-01

    We demonstrated robust and bend insensitive fiber delivery of high power pulsed laser with diffraction limited beam quality for two different kind of hollow core photonic band gap fibers......We demonstrated robust and bend insensitive fiber delivery of high power pulsed laser with diffraction limited beam quality for two different kind of hollow core photonic band gap fibers...

  15. Oscillations of disks

    CERN Document Server

    Kato, Shoji

    2016-01-01

    This book presents the current state of research on disk oscillation theory, focusing on relativistic disks and tidally deformed disks. Since the launch of the Rossi X-ray Timing Explorer (RXTE) in 1996, many high-frequency quasiperiodic oscillations (HFQPOs) have been observed in X-ray binaries. Subsequently, similar quasi-periodic oscillations have been found in such relativistic objects as microquasars, ultra-luminous X-ray sources, and galactic nuclei. One of the most promising explanations of their origin is based on oscillations in relativistic disks, and a new field called discoseismology is currently developing. After reviewing observational aspects, the book presents the basic characteristics of disk oscillations, especially focusing on those in relativistic disks. Relativistic disks are essentially different from Newtonian disks in terms of several basic characteristics of their disk oscillations, including the radial distributions of epicyclic frequencies. In order to understand the basic processes...

  16. Gyrotron whispering gallery mode coupler with a mode conversion reflector for exciting a circular symmetric uniform phase RF beam in a corrugated waveguide

    Science.gov (United States)

    Neilson, Jeffrey M.

    2017-07-25

    A cylindrical waveguide with a mode converter transforms a whispering gallery mode from a gyrotron cylindrical waveguide with a helical cut launch edge to a quasi-Gaussian beam suitable for conveyance through a corrugated waveguide. This quasi-Gaussian beam is radiated away from the waveguide using a spiral cut launch edge, which is in close proximity to a first mode converting reflector. The first mode converting reflector is coupled to a second mode converting reflector which provides an output free-space HE11 mode wave suitable for direct coupling into a corrugated waveguide. The radiated beam produced at the output of the second mode converting reflector is substantially circular.

  17. High power and high repetition solid state laser for EUV lithography

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, H.; Mitra, A.; Wang, T. and the others [Osaka Univ., Osaka (Japan)

    2004-07-01

    We have been developing a high repetition (5 kHz) and high power (5kW) Nd:YAG laser system for EUV lithography. Key subjects are (1) reliable front-end, (2) uniform and high density pumping of main amplifier rods, and (3) compensation of thermal effects. A stable and reliable front-end based on fiber lasers has been developed. As a cw oscillator using Yb-doped silica fiber operates single longitudinal mode at 1030 nm to 1080nm, various laser materials (Yb:YAG, Nd:YLF, Nd:YAG, Nd:YAP, etc) can be used as main laser medium. A fast LN EO modulator switches out arbitrary pulse shape with response time of 100 ps. Laser pulses from the modulator are amplified by 3 stage fiber amplifiers up to 1 J. We will focus our efforts to attain 1 mJ output from the fiber front-end. Output pulses from the front-end are amplified to 100 mJ level by two 4-mm rod amplifiers (Nd:YAG) and two 6-mm rod amplifiers. Main amplifier chain consists of eight 12-mm rod amplifiers pumped by cw laser diodes. Total output power of the laser diodes is 28.8 kW. Double pass geometry is required to get enough gain and to compensate thermal effects. Spatial filters are installed to adjust thermal lens in the amplifiers and to send an image into just the center of the amplifiers. Ninty degree rotators and faraday rotators are installed in order to compensate thermal birefringence. A test amplifier module was made for investigation on uniform pumping, thermal effects, gain properties, and so on. Six laser diode modules with 4.5 kW total output power are installed in symmetric configuration. Active medium is Nd:YAG rod with 0.6% doping. Diameter and length of the rod are 12 mm and 150 mm, respectively. Peak gain of 1.67 was obtained at 4.2 kW pumping power and 200s pumping duration. Pumping uniformity was measured by both gain distribution and spontaneous emission from the laser rod. Fairly good uniformity was achieved by adjusting pumping geometry. Detail system analysis suggests that 8 amplifier modules

  18. The Oscillator Principle of Nature

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2012-01-01

    Oscillators are found on all levels in Nature. The general oscillator concept is defined and investigated. Oscillators may synchronize into fractal patterns. Apparently oscillators are the basic principle in Nature. The concepts of zero and infinite are discussed. Electronic manmade oscillators...

  19. All-optical Q-switching limiter for high-power gigahertz modelocked diode-pumped solid-state lasers.

    Science.gov (United States)

    Klenner, Alexander; Keller, Ursula

    2015-04-06

    Passively modelocked diode-pumped solid-state lasers (DPSSLs) with pulse repetition rates in the gigahertz regime suffer from an increased tendency for Q-switching instabilities. Low saturation fluence intracavity saturable absorbers - such as the semiconductor saturable absorber mirrors (SESAMs) - can solve this problem up to a certain average output power limited by the onset of SESAM damage. Here we present a passive stabilization mechanism, an all-optical Q-switching limiter, to reduce the impact of Q-switching instabilities and increase the potential output power of SESAM modelocked lasers in the gigahertz regime. With a proper cavity design a Kerr lens induced negative saturable absorber clamps the maximum fluence on the SESAM and therefore limits the onset of Q-switching instabilities. No critical cavity alignment is required because this Q-switching limiter acts well within the cavity stability regime. Using a proper cavity design, a high-power diode-pumped Yb:CALGO solid-state laser generated sub-100 fs pulses with an average output power of 4.1 W at a pulse repetition rate of 5 GHz. With a pulse duration of 96 fs we can achieve a peak power as high as 7.5 kW directly from the SESAM modelocked laser oscillator without any further external pulse amplification and/or pulse compression. We present a quantitative analysis of this Kerr lens induced Q-switching limiter and its impact on modelocked operation. Our work provides a route to compact high-power multi-gigahertz frequency combs based on SESAM modelocked diode-pumped solid-state lasers without any additional external amplification or pulse compression.

  20. High-power ultralong-wavelength Tm-doped silica fiber laser cladding-pumped with a random distributed feedback fiber laser.

    Science.gov (United States)

    Jin, Xiaoxi; Du, Xueyuan; Wang, Xiong; Zhou, Pu; Zhang, Hanwei; Wang, Xiaolin; Liu, Zejin

    2016-07-15

    We demonstrated a high-power ultralong-wavelength Tm-doped silica fiber laser operating at 2153 nm with the output power exceeding 18 W and the slope efficiency of 25.5%. A random distributed feedback fiber laser with the center wavelength of 1173 nm was employed as pump source of Tm-doped fiber laser for the first time. No amplified spontaneous emissions or parasitic oscillations were observed when the maximum output power reached, which indicates that employing 1173 nm random distributed feedback fiber laser as pump laser is a feasible and promising scheme to achieve high-power emission of long-wavelength Tm-doped fiber laser. The output power of this Tm-doped fiber laser could be further improved by optimizing the length of active fiber, reflectivity of FBGs, increasing optical efficiency of pump laser and using better temperature management. We also compared the operation of 2153 nm Tm-doped fiber lasers pumped with 793 nm laser diodes, and the maximum output powers were limited to ~2 W by strong amplified spontaneous emission and parasitic oscillation in the range of 1900-2000 nm.

  1. A Conspiracy of Oscillators

    DEFF Research Database (Denmark)

    Hjorth, Poul G.

    2008-01-01

    We discuss nonlinear mechanical systems containing several oscillators whose frequecies are all much higher than frequencies associated with the remaining degrees of freedom. In this situation a near constant of the motion, an adiabatic invariant, exists which is the sum of all the oscillator...

  2. Hyperchaotic Oscillator with Gyrators

    DEFF Research Database (Denmark)

    Tamasevicius, A; Cenys, A; Mykolaitis, G.

    1997-01-01

    A fourth-order hyperchaotic oscillator is described. It contains a negative impedance converter, two gyratots, two capacitors and a diode. The dynamics of the oscillator is shown to be characterised by two positive Lyapunov exponents. The performance of the circuit is investigated by means...

  3. Grazing Impact Oscillations

    NARCIS (Netherlands)

    Weger, J.G.; Water, van de W.; Molenaar, J.

    2000-01-01

    An impact oscillator is a periodically driven system that hits a wall when its amplitude exceeds a critical value. We study impact oscillations where collisions with the wall are with near-zero velocity (grazing impacts). A characteristic feature of grazing impact dynamics is a geometrically

  4. Synchronization of hyperchaotic oscillators

    DEFF Research Database (Denmark)

    Tamasevicius, A.; Cenys, A.; Mykolaitis, G.

    1997-01-01

    Synchronization of chaotic oscillators is believed to have promising applications in secure communications. Hyperchaotic systems with multiple positive Lyapunov exponents (LEs) have an advantage over common chaotic systems with only one positive LE. Three different types of hyperchaotic electronic...... oscillators are investigated demonstrating synchronization by means of only one properly selected variable....

  5. Prediction of resonant oscillation

    DEFF Research Database (Denmark)

    2010-01-01

    oscillations and compare the measured oscillations using FFT analysis of signal correlations, variance analysis of signals and other comparisons. As an example, the presence of a growing peak around a frequency that doubles the roll natural frequency indicates the possibility that parametric roll is going...

  6. High frequency pressure oscillator for microcryocoolers

    Science.gov (United States)

    Vanapalli, S.; ter Brake, H. J. M.; Jansen, H. V.; Zhao, Y.; Holland, H. J.; Burger, J. F.; Elwenspoek, M. C.

    2008-04-01

    Microminiature pulse tube cryocoolers should operate at a frequency of an order higher than the conventional macro ones because the pulse tube cryocooler operating frequency scales inversely with the square of the pulse tube diameter. In this paper, the design and experiments of a high frequency pressure oscillator is presented with the aim to power a micropulse tube cryocooler operating between 300 and 80K, delivering a cooling power of 10mW. Piezoelectric actuators operate efficiently at high frequencies and have high power density making them good candidates as drivers for high frequency pressure oscillator. The pressure oscillator described in this work consists of a membrane driven by a piezoelectric actuator. A pressure ratio of about 1.11 was achieved with a filling pressure of 2.5MPa and compression volume of about 22.6mm3 when operating the actuator with a peak-to-peak sinusoidal voltage of 100V at a frequency of 1kHz. The electrical power input was 2.73W. The high pressure ratio and low electrical input power at high frequencies would herald development of microminiature cryocoolers.

  7. Magnetostatic wave oscillator frequencies

    Science.gov (United States)

    Sethares, J. C.; Stiglitz, M. R.; Weinberg, I. J.

    1981-03-01

    The frequencies of magnetostatic wave (MSW) oscillators employing three principal modes of propagation, surface (MSSW), forward (MSFVW), and backward (MSBVW) volume waves, have been investigated. Previous (MSW) oscillator papers dealt with MSSW. Oscillators were fabricated using LPE-YIG MSW delay lines in a feedback loop of a 2-4 GHz amplifier. Wide and narrow band transducers were employed. Oscillator frequency as a function of biasing field is in agreement with a theoretical analysis. The analysis predicts frequency in terms of material parameters, biasing field, and transducer geometry. With wide band transducers a comb of frequencies is generated. Narrow band transducers for MSSW and MSFVW select a single mode; and MSBVW selects two modes. Spurious modes, attributed to instrumentation, are more than 20 dB below the main response, and bandwidths are less than 0.005 percent. No other spurious modes are observed. MSW oscillators produce clean electronically tunable signals and appear attractive in frequency agile systems.

  8. [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.

  9. 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.

  10. Design and measurement of a TE{sub 13} input converter for high order mode gyrotron travelling wave amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan; Liu, Guo, E-mail: liuguo@uestc.edu.cn; Shu, Guoxiang; Yan, Ran; Wang, Li; Agurgo Balfour, E.; Fu, Hao; Luo, Yong [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Wang, Shafei, E-mail: rockingsandstorm@163.com [North Electronic Device Research Institution, Box 947, Beijing 100141 (China)

    2016-03-15

    A technique to launch a circular TE{sub 13} mode to interact with the helical electron beam of a gyrotron travelling wave amplifier is proposed and verified by simulation and cold test in this paper. The high order (HOM) TE{sub 13} mode is excited by a broadband Y-type power divider with the aid of a cylindrical waveguide system. Using grooves and convex strips loaded at the lateral planes of the output cylindrical waveguide, the electric fields of the potential competing TE{sub 32} and TE{sub 71} modes are suppressed to allow the transmission of the dominant TE{sub 13} mode. The converter performance for different structural dimensions of grooves and convex strips is studied in detail and excellent results have been achieved. Simulation predicts that the average transmission is ∼−1.8 dB with a 3 dB bandwidth of 7.2 GHz (91.5–98.7 GHz) and port reflection is less than −15 dB. The conversion efficiency to the TE{sub 32} and TE{sub 71} modes are, respectively, under −15 dB and −24 dB in the operating frequency band. Such an HOM converter operating at W-band has been fabricated and cold tested with the radiation boundary. Measurement from the vector network analyzer cold test and microwave simulations show a good reflection performance for the converter.

  11. High power plasma heating experiments on the Proto-MPEX facility

    Science.gov (United States)

    Bigelow, T. S.; Beers, C. J.; Biewer, T. M.; Caneses, J. F.; Caughman, J. B. O.; Diem, S. J.; Goulding, R. H.; Green, D. L.; Kafle, N.; Rapp, J.; Showers, M. A.

    2017-10-01

    Work is underway to maximize the power delivered to the plasma that is available from heating sources installed on the Prototype Materials Plasma Exposure eXperiment (Proto-MPEX) at ORNL. Proto-MPEX is a linear device that has a >100 kW, 13.56 MHz helicon plasma generator available and is intended for material sample exposure to plasmas. Additional plasma heating systems include a 10 kW 18 GHz electron cyclotron heating (ECH) system, a 25 kW 8 MHz ion cyclotron heating ICH system, and a 200 kW 28 GHz electron Bernstein wave (EBW) and ECH system. Most of the heating systems have relatively good power transmission efficiency, however, the 28 GHz EBW system has a lower efficiency owing to stringent requirements on the microwave launch characteristics for EBW coupling combined with the lower output mode purity of the early-model gyrotron in use and its compact mode converter system. A goal for the Proto-MPEX is to have a combined heating power of 200 kW injected into the plasma. Infrared emission diagnostics of the target plate combined with Thomson Scattering, Langmuir probe, and energy analyzer measurements near the target are utilized to characterize the plasmas and coupling efficiency of the heating systems. ORNL is managed by UT-Battelle, LLC, for the U.S. DOE under contract DE-AC-05-00OR22725.

  12. Electron cyclotron heating/current-drive system using high power tubes for QUEST spherical tokamak

    Science.gov (United States)

    Onchi, Takumi; Idei, H.; Hasegawa, M.; Nagata, T.; Kuroda, K.; Hanada, K.; Kariya, T.; Kubo, S.; Tsujimura, T. I.; Kobayashi, S.; Quest Team

    2017-10-01

    Electron cyclotron heating (ECH) is the primary method to ramp up plasma current non-inductively in QUEST spherical tokamak. A 28 GHz gyrotron is employed for short pulses, where the radio frequency (RF) power is about 300 kW. Current ramp-up efficiency of 0.5 A/W has been obtained with focused beam of the second harmonic X-mode. A quasi-optical polarizer unit has been newly installed to avoid arcing events. For steady-state tokamak operation, 8.56 GHz klystron with power of 200 kW is used as the CW-RF source. The high voltage power supply (54 kV/13 A) for the klystron has been built recently, and initial bench test of the CW-ECH system is starting. The array of insulated-gate bipolar transistor works to quickly cut off the input power for protecting the klystron. This work is supported by JSPS KAKENHI (15H04231), NIFS Collaboration Research program (NIFS13KUTR085, NIFS17KUTR128), and through MEXT funding for young scientists associated with active promotion of national university reforms.

  13. The use of segmented cathodes to determine the spoke current density distribution in high power impulse magnetron sputtering plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Poolcharuansin, Phitsanu [Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ (United Kingdom); The Technological Plasma Research Unit, Department of Physics, Mahasarakham University, Maha Sarakham 44150 (Thailand); Estrin, Francis Lockwood; Bradley, James W., E-mail: j.w.bradley@liverpool.ac.uk [Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ (United Kingdom)

    2015-04-28

    The localized target current density associated with quasi-periodic ionization zones (spokes) has been measured in a high power impulse magnetron sputtering (HiPIMS) discharge using an array of azimuthally separated and electrical isolated probes incorporated into a circular aluminum target. For a particular range of operating conditions (pulse energies up to 2.2 J and argon pressures from 0.2 to 1.9 Pa), strong oscillations in the probe current density are seen with amplitudes up to 52% above a base value. These perturbations, identified as spokes, travel around the discharge above the target in the E×B direction. Using phase information from the angularly separated probes, the spoke drift speeds, angular frequencies, and mode number have been determined. Generally, at low HiPIMS pulse energies E{sub p} < 0.8 J, spokes appear to be chaotic in nature (with random arrival times), however as E{sub p} increases, coherent spokes are observed with velocities between 6.5 and 10 km s{sup −1} and mode numbers m = 3 or above. At E{sub p} > 1.8 J, the plasma becomes spoke-free. The boundaries between chaotic, coherent, and no-spoke regions are weakly dependent on pressure. During each HiPIMS pulse, the spoke velocities increase by about 50%. Such an observation is explained by considering spoke velocities to be determined by the critical ionization velocity, which changes as the plasma composition changes during the pulse. From the shape of individual current density oscillations, it appears that the leading edge of the spoke is associated with a slow increase in local current density to the target and the rear with a more rapid decrease. The measurements show that the discharge current density associated with individual spokes is broadly spread over a wide region of the target.

  14. 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...

  15. High Power Narrow Linewidth 1.26 Micron Ho-Doped Fiber Amplifier Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of an innovative, high power, and extremely reliable 1.26-micron Ho-doped fluoride fiber amplifier. The proposed fiber amplifier...

  16. 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...

  17. High Performance Plasma Channel Insulators for High Power Hall Thrusters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA missions for planetary exploration require high power, long-life Hall thrusters. However, thruster power and lifetime are limited by the erosion of plasma...

  18. Compact, Low-Cost, Frequency-Locked Semiconductor Laser for Injection Seeding High Power Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This NASA Small Business Innovative Research Phase II project will develop a compact, low-cost, wavelength locked seed laser for injection locking high powered...

  19. High-power X- and Ka-band Gallium Nitride Amplifiers with Exceptional Efficiency Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Achieving very high-power amplification with maximum efficiency at X- and Ka-band is challenging using solid-state technology. Gallium Arsenide (GaAs) has been the...

  20. Energetic Ion Mitigation Methodology for High Power Plasma Thruster Cathodes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The presence of energetic ions, that appear under high cathode current operation, stand as a showstopper to the realization of high power electric propulsion....

  1. High-Power, High-Efficiency 1.907nm Diode Lasers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — nLight developed high-power, high-efficiency laser diodes emitting at 1907nm for the pumping of solid-state lasers during the Phase I. The innovation brought to bear...

  2. A Waveguide Based, High Power Pockels Cell Modulator for Sub-Nanosecond Pulse Slicing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Goal of this STTR is to develop a high speed, high power, waveguide based modulator (phase and amplitude) and investigate its use as a pulse slicer. The key...

  3. 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...

  4. 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...

  5. Efficient High Power 2 micron Tm3+-Doped Fiber Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of new Tm3+ doped germanate glass fibers for efficient high power 2-micron fiber lasers capable of generating an output power of...

  6. Efficient high power 2 micron Tm3+-Doped Fiber Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of new Tm3+ doped germanate glass fibers for efficient high power 2 micron fiber lasers capable of generating an output power of...

  7. High-Power, High-Efficiency 1.907nm Diode Lasers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — nLight proposes to develop high-power, high-efficiency laser diodes emitting at 1907nm. Performance is expected to improve from the current state-of-the-art...

  8. Design of the Trap Filter for the High Power Converters with Parallel Interleaved VSCs

    DEFF Research Database (Denmark)

    Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus

    2014-01-01

    The power handling capability of the state-of-the-art semiconductor devices is limited. Therefore, the Voltage Source Converters (VSCs) are often connected in parallel to realize high power converter. The switching frequency semiconductor devices, used in the high power VSCs, is also limited...... to sink the dominant harmonic frequency components. The design procedure of the line filter is illustrated and the filter performance is also verified by performing the simulation and the experimental study....

  9. Design Methodology of High Power Distributed Amplifier Employing Broadband Impedance Transformer

    DEFF Research Database (Denmark)

    Narendra, Kumar; Zhurbenko, Vitaliy; Collantes, Juan Mari

    2009-01-01

    A novel topology of a high power distributed amplifier (DA) in combination with a broadband impedance transformer is presented. The advantages of the proposed topology are explored analytically and verified by a full-wave 3D simulations. Stability of the high power DA is verified with the pole......-zero identification method. The described design methodology might be useful for industrial engineers to reduce development cycle time....

  10. Method and system for advancement of a borehole using a high power laser

    Science.gov (United States)

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

    2014-09-09

    There is provided a system, apparatus and methods for the laser drilling of a borehole in the earth. There is further provided with in the systems a means for delivering 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, a laser bottom hole assembly, and fluid directing techniques and assemblies for removing the displaced material from the borehole.

  11. Hardening Unmanned Aerial Systems Against High Power Microwave Threats in Support of Forward Operations

    Science.gov (United States)

    2017-04-01

    In each of these scenarios, counter-UAS (C-UAS) weapons utilizing pulsed high power microwave (HPM) energy pose a significant problem for UAS in...offensive and defensive combat roles. These weapons cause electromagnetic interference (EMI) to produce effects on UAS ranging from upset to system...operations, their vulnerability to counter-UAS weapons utilizing high power microwaves (HPM) must be explored and mitigated. Defining this unique problem

  12. Parametric design and protective strategy of energy module for SG-III high power laser

    CERN Document Server

    Liu Ke Fu; Qing Shi Hong; Pan Yuan; Yao Zeng Gan; Pi Zhang; Zheng Wan Guo; Guo Liang Fu; Zhou Pei Zhang; Li Yi Zheng; Chen De Huai

    2001-01-01

    The author presented the circuitry design and principle of parameters choice of the energy module for SG-III high power laser. All possible faults of high pulsed power supply were analyzed in detail. Based on the analysis and computation, the protective strategy and technology was put forward. It is helpful for the design and safe operation of high power supply and laser amplifier system. The experiments showed that the manufactured pulsed power supply met the system requirements

  13. Methods for enhancing the efficiency of creating a borehole using high power laser systems

    Science.gov (United States)

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

    2014-06-24

    Methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena to enhance the formation of Boreholes. Methods for the laser operations to reduce the critical path for forming a borehole in the earth. These methods can deliver high power laser energy down a deep borehole, while maintaining the high power to perform operations in such boreholes deep within the earth.

  14. Optical fiber cable for transmission of high power laser energy over great distances

    Science.gov (United States)

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

    2016-05-24

    There is provided a system and apparatus for the transmission of high power laser energy over great distances without substantial power loss and without the presence of stimulated Raman scattering. There is further provided systems and optical fiber cable configurations and optical fiber structures for the delivering high power laser energy over great distances to a tool or surface to perform an operation or work with the tool or upon the surface.

  15. Optical Properties of Lithium Terbium Fluoride and Implications for Performance in High Power Lasers (Postprint)

    Science.gov (United States)

    2016-02-01

    AFRL-RX-WP-JA-2016-0323 OPTICAL PROPERTIES OF LITHIUM TERBIUM FLUORIDE AND IMPLICATIONS FOR PERFORMANCE IN HIGH POWER LASERS... AMERICA (STINFO COPY) AIR FORCE RESEARCH LABORATORY MATERIALS AND MANUFACTURING DIRECTORATE WRIGHT-PATTERSON AIR FORCE BASE, OH 45433-7750 AIR...OPTICAL PROPERTIES OF LITHIUM TERBIUM FLUORIDE AND IMPLICATIONS FOR PERFORMANCE IN HIGH POWER LASERS (POSTPRINT) 5a. CONTRACT NUMBER IN-HOUSE 5b

  16. A high powered radar interference mitigation technique for communications signal recovery with fpga implementation

    Science.gov (United States)

    2017-03-01

    sensing functions can coexist and yet still operate as designed [3]–[6]. There may be times when it is necessary to have communications and radar signals...The two situations we consider are high-power-in-band radar interference and the common-carrier concept of operations (CONOP). The emphasis of this...develop an interference mitigation algorithm to demodulate a communications signal that is interfered by a high-powered radar operating on the same

  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 Altitude Electromagnetic Pulse (HEMP) and High Power Microwave (HPM) Devices: Threat Assessments

    Science.gov (United States)

    2008-07-21

    against HEMP effects resulting from a nuclear exchange.40 The Limited Test Ban Treaty of 1963 prohibits nuclear explosions in the atmosphere, in space, and...Order Code RL32544 High Altitude Electromagnetic Pulse ( HEMP ) and High Power Microwave (HPM) Devices: Threat Assessments Updated July 21, 2008 Clay...2008 to 00-00-2008 4. TITLE AND SUBTITLE High Altitude Electromagnetic Pulse ( HEMP ) and High Power Microwave (HPM) Devices: Threat Assessments 5a

  19. A method of reactor power decrease by 2DOF control system during BWR power oscillation

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Nobuyuki; Suzuki, Katsuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-09-01

    Occurrence of power oscillation events caused by void feedback effects in BWRs operated at low-flow and high-power condition has been reported. After thoroughly examining these events, BWRs have been equipped with the SRI (Selected Rod Insertion) system to avoid the power oscillation by decreasing the power under such reactor condition. This report presents a power control method for decreasing the reactor power stably by a two degree of freedom (2DOF) control. Performing a numerical simulation by utilizing a simple reactor dynamics model, it is found that the control system designed attains a satisfactory control performance of power decrease from a viewpoint of setting time and oscillation. (author)

  20. 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.

  1. Neutrino Oscillation Physics

    CERN Document Server

    Kayser, Boris

    2014-04-10

    To complement the neutrino-physics lectures given at the 2011 International School on Astro Particle Physics devoted to Neutrino Physics and Astrophysics (ISAPP 2011; Varenna, Italy), at the 2011 European School of High Energy Physics (ESHEP 2011; Cheila Gradistei, Romania), and, in modified form, at other summer schools, we present here a written description of the physics of neutrino oscillation. This description is centered on a new way of deriving the oscillation probability. We also provide a brief guide to references relevant to topics other than neutrino oscillation that were covered in the lectures.

  2. Classical oscillator driven by an oscillating chirped force

    NARCIS (Netherlands)

    Khachatryan, A.G.; van Goor, F.A.; Boller, Klaus J.

    2006-01-01

    The motion of a classical (harmonic) oscillator is studied in the case where the oscillator is driven by a pulsed oscillating force with a frequency varying in time (frequency chirp). The amplitude and phase of the oscillations left after the pulsed force in dependence on the profile and strength of

  3. High frequency nanotube oscillator

    Science.gov (United States)

    Peng, Haibing [Houston, TX; Zettl, Alexander K [Kensington, TX

    2012-02-21

    A tunable nanostructure such as a nanotube is used to make an electromechanical oscillator. The mechanically oscillating nanotube can be provided with inertial clamps in the form of metal beads. The metal beads serve to clamp the nanotube so that the fundamental resonance frequency is in the microwave range, i.e., greater than at least 1 GHz, and up to 4 GHz and beyond. An electric current can be run through the nanotube to cause the metal beads to move along the nanotube and changing the length of the intervening nanotube segments. The oscillator can operate at ambient temperature and in air without significant loss of resonance quality. The nanotube is can be fabricated in a semiconductor style process and the device can be provided with source, drain, and gate electrodes, which may be connected to appropriate circuitry for driving and measuring the oscillation. Novel driving and measuring circuits are also disclosed.

  4. Neutrino anomalies without oscillations

    Indian Academy of Sciences (India)

    conventional' neutrino oscillations induced by mass-mixing. Several of these require non-zero neutrino masses as well. Author Affiliations. Sandip Pakvasa1. Department of Physics and Astronomy, University of Hawaii, Honolulu, HI 96822, USA ...

  5. Neural Oscillators Programming Simplified

    Directory of Open Access Journals (Sweden)

    Patrick McDowell

    2012-01-01

    Full Text Available The neurological mechanism used for generating rhythmic patterns for functions such as swallowing, walking, and chewing has been modeled computationally by the neural oscillator. It has been widely studied by biologists to model various aspects of organisms and by computer scientists and robotics engineers as a method for controlling and coordinating the gaits of walking robots. Although there has been significant study in this area, it is difficult to find basic guidelines for programming neural oscillators. In this paper, the authors approach neural oscillators from a programmer’s point of view, providing background and examples for developing neural oscillators to generate rhythmic patterns that can be used in biological modeling and robotics applications.

  6. solar neutrino oscillation phenomenology

    Indian Academy of Sciences (India)

    The sMA region and a large part of the vacuum oscillation region are seen to have been washed away with the inclusion of the sK spectrum data. In the left panel of figure 4 we show the dependence of the probabilities on energy. In the sMA and the VO oscillation regions the probability has a non- monotonic dependence ...

  7. Self-oscillation

    CERN Document Server

    Jenkins, Alejandro

    2011-01-01

    Physicists are very familiar with forced and parametric resonance, but usually not with self-oscillation, a property of certain linear systems that gives rise to a great variety of vibrations, both useful and destructive. In a self-oscillator, the driving force is controlled by the oscillation itself so that it acts in phase with the velocity, causing a negative damping that feeds energy from the environment into the vibration: no external rate needs to be tuned to the resonant frequency. A paper from 1830 by G. B. Airy gives us the opening to introduce self-oscillation as a sort of "perpetual motion" responsible for the human voice. The famous collapse of the Tacoma Narrows bridge in 1940, often attributed by introductory physics texts to forced resonance, was actually a self-oscillation, as was the more recent swaying of the London Millenium Footbridge. Clocks are self-oscillators, as are bowed and wind musical instruments, and the heartbeat. We review the criterion that determines whether an arbitrary line...

  8. 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...

  9. 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...

  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. Manufacturing Technology Development of Advanced Components for High Power Solid State Lasers

    Science.gov (United States)

    2010-07-19

    controlled KTiOP04 optical parametric oscillator," Opt. Lett. 32, 274-276 (2007). [2] P. B. Phua, B. S. Tan, R. F. Wu, K. S. Lai, L. Chia , E. Lau...ultrafast seed laser, 1st amplifier stage, 2 a amplifier stage, and beam characterization equipment. 4. Ti:Sapphire Laser Oscillator, Pre-Amplifier, and

  12. 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)

  13. Qualifying plasma diagnostics for a high power microwave background of ECRH heated discharges

    Energy Technology Data Exchange (ETDEWEB)

    Hirsch, M.; Baldzuhn, J.; Endler, M.; Laux, M.; Zhang, D.; Laqua, H.P.; Noke, F.; Purps, F.; Ewert, K. [Max-Planck Institut fur Plasmaphysik, EURATOM Association, D-17491 Greifswald (Germany); Oosterbeek, J.W. [Technische Universiteit Eindhoven, Den Doelch 2, 5612 AZ Eindhoven (Netherlands); Jimenez, R. [Associacion EURATOM/CIEMAT, av. Complutense 22, 28040, Madrid (Spain)

    2011-07-01

    Microwave background radiation resulting from multiple reflected unabsorbed ECRH / ECCD power may cause severe problems for microwave absorbing in-vessel components such as gaskets, bellows, windows, isolators and cable insulations in particular during long pulse operation. For qualifying in-vessel components of W7-X in the environment of an isotropic 140 GHz radiation the Microwave Stray Radiation Launch facility, MISTRAL is operated at IPP. Power flux densities of 10-40 kW/m{sup 2} are obtained with a pulsed power gyrotron launching the microwave via a corrugated transmission line and a vacuum window to the MISTRAL vessel. The focus of the program was on cable isolations as required e.g. for in-vessel magnetic diagnostics. Sufficient shielding is obtained in nearly closed metal pipes only. Cryo pumps require a temperature < 12 K where Hydrogen desorption starts. The cryo pumps are usually shielded from plasma radiation by so called chevron structures. It is investigated whether coating of these chevrons with a microwave absorbing layer yields a sufficient reduction of the stray radiation level to ensure cryo pump operation. Diagnostic windows have been tested also. Although the temperature rise even of uncooled ZnSe and quartz windows at 10 kW/m{sup 2} is uncritical with respect to damage the associated refractive index changes may be too high for some diagnostic purposes e.g. for interferometry. A possible shielding are meshes or {mu}W absorbing coatings. Integrated diagnostic mock-ups such as for the diamagnetic loop, the inner Rogowski coils, Mirnov coils and the bolometer head also have been tested

  14. 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.

  15. High power x-ray welding of metal-matrix composites

    Science.gov (United States)

    Rosenberg, Richard A.; Goeppner, George A.; Noonan, John R.; Farrell, William J.; Ma, Qing

    1999-01-01

    A method for joining metal-matrix composites (MMCs) by using high power x-rays as a volumetric heat source is provided. The method involves directing an x-ray to the weld line between two adjacent MMCs materials to create an irradiated region or melt zone. The x-rays have a power density greater than about 10.sup.4 watts/cm.sup.2 and provide the volumetric heat required to join the MMC materials. Importantly, the reinforcing material of the metal-matrix composites remains uniformly distributed in the melt zone, and the strength of the MMCs are not diminished. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys.

  16. 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.

  17. 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.

  18. Irradiation Tests Supporting LEU Conversion of Very High Power Research Reactors in the US

    Energy Technology Data Exchange (ETDEWEB)

    Woolstenhulme, N. E.; Cole, J. I.; Glagolenko, I.; Holdaway, K. K.; Housley, G. K.; Rabin, B. H.

    2016-10-01

    The US fuel development team is developing a high density uranium-molybdenum alloy monolithic fuel to enable conversion of five high-power research reactors. Previous irradiation tests have demonstrated promising behavior for this fuel design. A series of future irradiation tests will enable selection of final fuel fabrication process and provide data to qualify the fuel at moderately-high power conditions for use in three of these five reactors. The remaining two reactors, namely the Advanced Test Reactor and High Flux Isotope Reactor, require additional irradiation tests to develop and demonstrate the fuel’s performance with even higher power conditions, complex design features, and other unique conditions. This paper reviews the program’s current irradiation testing plans for these moderately-high irradiation conditions and presents conceptual testing strategies to illustrate how subsequent irradiation tests will build upon this initial data package to enable conversion of these two very-high power research reactors.

  19. Tunable high-power narrow-linewidth green external-cavity GaN diode laser

    DEFF Research Database (Denmark)

    Chi, Mingjun; Jensen, Ole Bjarlin; Petersen, Paul Michael

    2016-01-01

    A tunable high-power green external-cavity diode laser is demonstrated. Up to 290 mW output power and a 9.2 nm tuning is achieve. This constitutes the highest output power from a tunable green diode laser system.......A tunable high-power green external-cavity diode laser is demonstrated. Up to 290 mW output power and a 9.2 nm tuning is achieve. This constitutes the highest output power from a tunable green diode laser system....

  20. Strong Scattering of High Power Millimeter Waves in Tokamak Plasmas with Tearing Modes

    DEFF Research Database (Denmark)

    Westerhof, E.; Nielsen, Stefan Kragh; Oosterbeek, J.W.

    2009-01-01

    In tokamak plasmas with a tearing mode, strong scattering of high power millimeter waves, as used for heating and noninductive current drive, is shown to occur. This new wave scattering phenomenon is shown to be related to the passage of the O point of a magnetic island through the high power...... heating beam. The density determines the detailed phasing of the scattered radiation relative to the O-point passage. The scattering power depends strongly nonlinearly on the heating beam power. ©2009 The American Physical Society...

  1. An Evaluation of the Cutting Potential of Different Types of High Power Lasers

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    2006-01-01

    based upon the historical development, the available cutting mechanisms understanding and the critical parameters involved in high power laser cutting. From the theoretical point of view, the new laser sources, the Disc-laser and the Fibre laser possess a potential of changing dramatically the limits......Laser cutting is a widespread industrial process. The boundaries for the performance of the lasers in terms of cutting capabilities is steadily moving towards higher cutting rates and thicker section cutting. In this paper the potential of different high power laser sources in cutting is evaluated...

  2. Development of High-Power Hall Thruster Power Processing Units at NASA GRC

    Science.gov (United States)

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

    2015-01-01

    NASA GRC successfully designed, built and tested four different power processor concepts for high power Hall thrusters. Each design satisfies unique goals including the evaluation of a novel silicon carbide semiconductor technology, validation of innovative circuits to overcome the problems with high input voltage converter design, development of a direct-drive unit to demonstrate potential benefits, or simply identification of lessonslearned from the development of a PPU using a conventional design approach. Any of these designs could be developed further to satisfy NASA's needs for high power electric propulsion in the near future.

  3. Laser-driven plasma photonic crystals for high-power lasers

    Science.gov (United States)

    Lehmann, G.; Spatschek, K. H.

    2017-05-01

    Laser-driven plasma density gratings in underdense plasma are shown to act as photonic crystals for high power lasers. The gratings are created by counterpropagating laser beams that trap electrons, followed by ballistic ion motion. This leads to strong periodic plasma density modulations with a lifetime on the order of picoseconds. The grating structure is interpreted as a plasma photonic crystal time-dependent property, e.g., the photonic band gap width. In Maxwell-Vlasov and particle-in-cell simulations it is demonstrated that the photonic crystals may act as a frequency filter and mirror for ultra-short high-power laser pulses.

  4. Ku and K band GaN High Power Amplifier MMICs

    Science.gov (United States)

    2017-03-20

    Ku- and K -band GaN High Power Amplifier MMICs Val Kaper, Scott Harris, Keith Kessler Raytheon, Andover MA 01810 vkaper@raytheon.com Abstract: This...paper describes development and characteri- zation of three Ku- and K -band GaN High Power Amplifier (HPA) MMICs. The circuits are implemented in...delivers 25 Watts of output power with 45% PAE. A K -band HPA operates from 19.5 to 22 GHz and delivers 18 Watts of output power with 29% PAE

  5. High Power Efficiency Buck Converter Design for Standalone Wind Generation System

    OpenAIRE

    Yigeng Huangfu; Ruiqing Ma; Bo Liang; Yuren Li

    2015-01-01

    In wind generation system, the power converter efficiency is one of the key factors for the performance of the system. In those systems, DC/DC Buck converter is widely used for high power system. Considering the converter’s cost and efficiency, this paper mainly focuses on the design of an improved topology Buck converter adopted for high power standalone wind generation system. The designed converter uses multi-MOSFETs in parallel instead of the IGBTs, in order to increase the conductive cur...

  6. Millimeter-Wave Power-Combining with Radiating Oscillator Arrays.

    Science.gov (United States)

    York, Robert Armstrong

    The next generation of communications and radar systems will soon begin to exploit the millimeter-wave portion of the electromagnetic spectrum. Such systems will require a high-power source of millimeter-wave energy, ideally small, lightweight, highly efficient, and failure -proof over a span of decades. Circuits using semiconductor devices have proved useful for this purpose at lower frequencies, but unfortunately the power generating capacity of solid -state devices diminishes quickly as frequencies approach 100 GHz. This has forced designers to use bulky, inefficient, and unreliable (but high-power) vacuum-tube sources. Combining the power produced by a large number of individual solid-state devices has been suggested as a means of overcoming the inherent limitations of millimeter -wave devices. In order to compete with vacuum-tube sources, power-combiners would require up to 1000 devices, presenting a difficult engineering challenge. This thesis introduces one possible solution to this problem. The proposed concept uses arrays of millimeter-wave oscillators, where each oscillator contains one or more active devices in a planar radiating structure. The oscillators are weakly coupled to synchronize frequency and phase relationships, and the power produced by each oscillator is radiatively combined in free-space, which gives rise to very high combining efficiencies. The array concept has been demonstrated at microwave frequencies using both Gunn and MESFET devices in a 4 x 4 patch antenna configuration. The Gunn array produced 22 Watts Equivalent Radiated Power (ERP), and the MESFET array produced 10 Watts ERP. A new theory has been developed which describes the coupled-oscillator dynamics, and has been shown to accurately predict experimentally observed effects. In addition to strict CW power-combining, a new mode of operation has been discovered which enables the same arrays to generate high-power pulses of energy. This new effect involves a "mode

  7. MMIC Replacement for Gunn Diode Oscillators

    Science.gov (United States)

    Crowe, Thomas W.; Porterfield, David

    2011-01-01

    An all-solid-state replacement for high-frequency Gunn diode oscillators (GDOs) has been proposed for use in NASA s millimeter- and submillimeter-wave sensing instruments. Highly developed microwave oscillators are used to achieve a low-noise and highly stable reference signal in the 10-40-GHz band. Compact amplifiers and high-power frequency multipliers extend the signal to the 100-500-GHz band with minimal added phase noise and output power sufficient for NASA missions. This technology can achieve improved output power and frequency agility, while maintaining phase noise and stability comparable to other GDOs. Additional developments of the technology include: a frequency quadrupler to 145 GHz with 18 percent efficiency and 15 percent fixed tuned bandwidth; frequency doublers featuring 124, 240, and 480 GHz; an integrated 874-GHz subharmonic mixer with a mixer noise temperature of 3,000 K DSB (double sideband) and mixer conversion loss of 11.8 dB DSB; a high-efficiency frequency tripler design with peak output power of 23 mW and 14 mW, and efficiency of 16 and 13 percent, respectively; millimeter-wave integrated circuit (MMIC) power amplifiers to the 30-40 GHz band with high DC power efficiency; and an 874-GHz radiometer suitable for airborne observation with state-of-the-art sensitivity at room temperature and less than 5 W of total power consumption.

  8. Oscillations in neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Hoeye, Gudrun Kristine

    1999-07-01

    We have studied radial and nonradial oscillations in neutron stars, both in a general relativistic and non-relativistic frame, for several different equilibrium models. Different equations of state were combined, and our results show that it is possible to distinguish between the models based on their oscillation periods. We have particularly focused on the p-, f-, and g-modes. We find oscillation periods of II approx. 0.1 ms for the p-modes, II approx. 0.1 - 0.8 ms for the f-modes and II approx. 10 - 400 ms for the g-modes. For high-order (l (>{sub )} 4) f-modes we were also able to derive a formula that determines II{sub l+1} from II{sub l} and II{sub l-1} to an accuracy of 0.1%. Further, for the radial f-mode we find that the oscillation period goes to infinity as the maximum mass of the star is approached. Both p-, f-, and g-modes are sensitive to changes in the central baryon number density n{sub c}, while the g-modes are also sensitive to variations in the surface temperature. The g-modes are concentrated in the surface layer, while p- and f-modes can be found in all parts of the star. The effects of general relativity were studied, and we find that these are important at high central baryon number densities, especially for the p- and f-modes. General relativistic effects can therefore not be neglected when studying oscillations in neutron stars. We have further developed an improved Cowling approximation in the non-relativistic frame, which eliminates about half of the gap in the oscillation periods that results from use of the ordinary Cowling approximation. We suggest to develop an improved Cowling approximation also in the general relativistic frame. (Author)

  9. Non-linear oscillations

    CERN Document Server

    Hagedorn, Peter

    1982-01-01

    Thoroughly revised and updated, the second edition of this concise text provides an engineer's view of non-linear oscillations, explaining the most important phenomena and solution methods. Non-linear descriptions are important because under certain conditions there occur large deviations from the behaviors predicted by linear differential equations. In some cases, completely new phenomena arise that are not possible in purely linear systems. The theory of non-linear oscillations thus has important applications in classical mechanics, electronics, communications, biology, and many other branches of science. In addition to many other changes, this edition has a new section on bifurcation theory, including Hopf's theorem.

  10. Brownian parametric oscillators

    Science.gov (United States)

    Zerbe, Christine; Jung, Peter; Hänggi, Peter

    1994-05-01

    We discuss the stochastic dynamics of dissipative, white-noise-driven Floquet oscillators, characterized by a time-periodic stiffness. Thus far, little attention has been paid to these exactly solvable nonstationary systems, although they carry a rich potential for several experimental applications. Here, we calculate and discuss the mean values and variances, as well as the correlation functions and the Floquet spectrum. As one main result, we find for certain parameter values that the fluctuations of the position coordinate are suppressed as compared to the equilibrium value of a harmonic oscillator (parametric squeezing).

  11. Friedel oscillations in graphene

    DEFF Research Database (Denmark)

    Lawlor, J. A.; Power, S. R.; Ferreira, M.S.

    2013-01-01

    Symmetry breaking perturbations in an electronically conducting medium are known to produce Friedel oscillations in various physical quantities of an otherwise pristine material. Here we show in a mathematically transparent fashion that Friedel oscillations in graphene have a strong sublattice...... asymmetry. As a result, the presence of impurities and/or defects may impact the distinct graphene sublattices very differently. Furthermore, such an asymmetry can be used to explain the recent observations that nitrogen atoms and dimers are not randomly distributed in graphene but prefer to occupy one...

  12. Broadband, high-power, continuous-wave, mid-infrared source using extended phase-matching bandwidth in MgO:PPLN.

    Science.gov (United States)

    Das, Ritwick; Kumar, S Chaitanya; Samanta, G K; Ebrahim-Zadeh, M

    2009-12-15

    We report a compact and viable source of broadband, high-power, cw, mid-IR radiation based on a singly resonant optical parametric oscillator (SRO) pumped by a wide-bandwidth cw Yb fiber laser centered at 1060 nm. By exploiting the extended phase-matching bandwidth in a 50 mm crystal of MgO:PPLN and a ring SRO cavity, we obtain 5.3 W of broadband idler output for 25.5 W of pump at >80% depletion, transferring a pump bandwidth of 73.9 cm(-1) to an idler spectrum spread across an equal bandwidth centered at 3454 nm. By deploying output coupling of the signal, we generate 11.2 W of total power at 44% extraction efficiency with a pump depletion of >73% at the maximum available pump power. Measurements of transverse modal power confirm Gaussian distribution of signal and idler beams.

  13. Rapid Sintering of Silica Xerogel Ceramic Derived from Sago Waste Ash Using Sub-millimeter Wave Heating with a 300 GHz CW Gyrotron

    Science.gov (United States)

    Aripin, Haji; Mitsudo, Seitaro; Sudiana, I. Nyoman; Tani, Shinji; Sako, Katsuhide; Fujii, Yutaka; Saito, Teruo; Idehara, Toshitaka; Sabchevski, Sliven

    2011-06-01

    In this paper, we present and discuss experimental results from a microwave sintering of a silica-glass ceramic, produced from a silica xerogel extracted from a sago waste ash. As a radiation source for the microwave heating a sub-millimeter wave gyrotron (Gyrotron FU CW I) with an output frequency of 300 GHz has been used. The powders of silica xerogel have been dry pressed and then sintered at temperatures ranging from 300°C to 1500°C. The influence of the sintering temperature on the technological properties such as porosity and bulk density was studied in detail. Furthermore, X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy have been used in order to study the structure of the produced silica glass-ceramics. It has been found that the silica xerogel crystallizes at a temperature of 800°C, which is about 200°C lower than the one observed in the conventional process. The silica xerogel samples sintered by their irradiation with a sub-millimeter wave at 900°C for 18 minutes are fully crystallized into a silica glass-ceramic with a density of about 2.2 g/cm3 and cristobalite as a major crystalline phase. The results obtained in this study allow one to conclude that the microwave sintering with sub-millimeter waves is an appropriate technological process for production of silica glass-ceramics from a silica xerogel and is characterized with such advantages as shorter times of the thermal cycle, lower sintering temperatures and higher quality of the final product.

  14. Thermal modeling for advanced high power packaging development and on-line performance monitoring

    NARCIS (Netherlands)

    Yuan, C.; Xiao, A.; Salta, J.; Langen, M. de; Driel, W. van

    2010-01-01

    As the market demands for high power and high efficiency power electronics, the industries has developed advanced IC technology and conceptual configuration. However, in order to guarantee the performance and reliability of the power electronics, the challenge of the packaging arises. This paper

  15. Effects of high power illuminators on vision through windscreens and driving behavior

    NARCIS (Netherlands)

    Toet, A.; Alferdinck, J.W.A.M.

    2013-01-01

    In this study we investigated the effectiveness of high power illuminators that are intended to be used as warning devices or non-lethal weapons to deny car drivers their view on the outside world through windscreens. The test is based on a measurement of the amount of veiling glare resulting when a

  16. Microstructural evolution in additive manufacturing with high power lasers : Deposition, characterization and performance

    NARCIS (Netherlands)

    Nenadl, Ondrej

    2017-01-01

    High power lasers provide time and cost effective method for metallic surface modification. In this work these modifications are explored as: 1) a simple melting and subsequent rapid solidification of a metallic surface – resulting in superior properties post-treatment; 2) deposition of an

  17. Widely Tunable High-Power Tapered Diode Laser at 1060 nm

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Sumpf, Bernd; Erbert, Götz

    2011-01-01

    We report a large tuning range from 1018 to 1093 nm from a InGaAs single quantum-well 1060-nm external cavity tapered diode laser. More than 2.5-W output power has been achieved. The tuning range is to our knowledge the widest obtained from a high-power InGaAs single quantum-well tapered laser...

  18. 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

  19. Impact of gain saturation on the mode instability threshold in high-power fiber amplifiers

    DEFF Research Database (Denmark)

    Hansen, Kristian Rymann; Lægsgaard, Jesper

    2014-01-01

    We present a coupled-mode model of transverse mode instability in high-power fiber amplifiers, which takes the effect of gain saturation into account. The model provides simple semi-analytical formulas for the mode instability threshold, which are valid also for highly saturated amplifiers...

  20. Degradation Processes in High-Power Diode Lasers under External Optical Feedback

    DEFF Research Database (Denmark)

    Tomm, Jens. W.; Hempel, Martin; Petersen, Paul Michael

    2013-01-01

    The effect of moderate external feedback on the gradual degradation of 808 nm emitting AlGaAs-based high-power broad-area diode lasers is analyzed. Eventually the quantum well that actually experiences the highest total optical load remains unaffected by the aging, while severe impact...

  1. Integrated Automotive High-Power LED-Lighting Systems in 3D-MID Technology

    NARCIS (Netherlands)

    Thomas, W.

    2014-01-01

    The growing energy consumption of lighting as well as rising luminous efficacies and -fluxes of high-power Light Emitting Diodes (LEDs) have contributed to the widespread use of LEDs in modern lighting systems. One of the most prominent users of the LED-technology is automotive (exterior) lighting.

  2. 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

  3. 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.

  4. High Power L-band T/R Module for Spaceborne SAR

    NARCIS (Netherlands)

    Knight, A.; Head, A.; Graaf, M.W. van der; Ludwig, L.; Vogel, P.; Gallou, N. le

    2006-01-01

    Within the framework of the pre-development for a TerraSAR-L space-borne mission a high power Transmit/Receive module was required to meet stringent requirements. The module is to be capable of delivering more than 40 watts of output power, in pulsed transmit mode, while having a Noise Figure of 2.8

  5. 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...

  6. High-power diode-pumped Tm:YLF slab laser

    CSIR Research Space (South Africa)

    Schellhorn, M

    2009-06-01

    Full Text Available The aim is to develop a high-power Tm:YLF slab laser which can be utilized to pump a Ho slab laser. A 68 W Tm:YLF slab laser was recently presented in [1] pumped from one end by a single 6-bar stack delivering ~300 W of pump power. In this work, we...

  7. Novel organic SMD package for high-power millimeter wave MMICs

    NARCIS (Netherlands)

    Heijningen, M. van; Friday, J.

    2004-01-01

    In this paper a novel low-cost SMD package for high-power MMICs is presented. Due to the special design this package has a very low thermal resistance and low parasitic ground inductance. 3D EM simulations of a packaged through-line correspond well with measurements. Measurement results of a 1 Watt

  8. Study of the general plasma characteristics of a high power multifilament ion source

    Energy Technology Data Exchange (ETDEWEB)

    Schoenberg, K.F.

    1979-09-01

    A general assessment of the steady state and time dependent plasma properties which characterize a high power multifilament ion source is presented. Steady state measurements, obtained via a pulsed electrostatic probe data acquisition system, are described. Fluctuation measurements, obtained via a broadband digital spectral analysis system, are also given.

  9. High power laser-mechanical drilling bit and methods of use

    Science.gov (United States)

    Grubb, Daryl L.; Kolachalam, Sharath K.; Faircloth, Brian O.; Rinzler, Charles C.; Allen, Erik C.; Underwood, Lance D.; Zediker, Mark S.

    2017-02-07

    An apparatus with a high power laser-mechanical bit for use with a laser drilling system and a method for advancing a borehole. The laser-mechanical bit has a beam path and mechanical removal devices that provide for the removal of laser-affected rock to advance a borehole.

  10. 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.

  11. High power singlemode GaInAs lasers with distributed Bragg reflectors

    Science.gov (United States)

    O'Brien, S.; Parke, R.; Welch, D. F.; Mehuys, D.; Scifres, D.

    1992-01-01

    High power singlemode strained GaInAs lasers have been fabricated which use buried second order gratings as distributed Bragg reflectors. The lasers operate in an edge emitting fashion with CW powers in excess of 110 mW with single longitudinal and transverse mode operation at 971.9 nm up to 42 mW.

  12. Rugged passively cooled high power laser fiber optic connectors and methods of use

    Science.gov (United States)

    Rinzler, Charles C.; Gray, William C.; Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.; McKay, Ryan P.

    2016-06-07

    There are provided high power laser connectors and couplers and methods that are capable of providing high laser power without the need for active cooling to remote, harsh and difficult to access locations and under difficult and harsh conditions and to manage and mitigate the adverse effects of back reflections.

  13. Workshop: Research and development plans for high power spallation neutron testing at BNL

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-05

    This report consists of vugraphs from presentations at the meeting. The papers covered the following topics: (1) APS as a proton source; (2) target status for NSNS (National Spallation Neutron Source); (3) spallation neutron source in Japan; (4) liquid LiBi flow loop; and (5) research and development plans for high power tests at the AGS.

  14. 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

  15. Ka-Band AlGaN/GaN HEMT high power and driver amplifier MMICs

    NARCIS (Netherlands)

    Heijningen, M. van; Vliet, F.E. van; Quay, R.; Raay, F. van; Kiefer, R.; Mueller, S.; Krausse, D.; Seelmann-Eggebert, M.; Mikulla, M.; Schlechtweg, M.

    2005-01-01

    In this paper the MMIC technology, design and characterization of a high power amplifier and driver amplifier MMIC at 30 GHz in AlGaN/GaN HEMT technology are presented. The MMICs are designed using CPW technology on a 390 μm thick SiC substrate. The measured small-signal gain of the driver is 14 dB

  16. Recent Results in High Power CO2-Laser Cutting for Shipbuilding Industry

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Juhl, Thomas Winther; Nielsen, Jakob Skov

    2003-01-01

    In 1997 a high power laser cutting and welding test facility was established at the Danish shipyard Odense Steel Shipyard (OSS). Research and development projects were initiated in order to establish the basis for applying the full power of the laser for laser-cutting, by developing mirror based...... cutting systems. In this paper the results of these projects will be presented....

  17. 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

  18. Preliminary design of high-power wave-guide/transmission system ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 59; Issue 5. Preliminary design of high-power wave-guide/transmission system for multimegawatt CW requirements of 100 MeV proton LINAC. Purushottam Shrivastava Y D Wanmode P R Hannurkar. Volume 59 Issue 5 November 2002 pp 829-834 ...

  19. Thermo-optical effects in high-power Ytterbium-doped fiber amplifiers

    DEFF Research Database (Denmark)

    Hansen, Kristian Rymann; Alkeskjold, Thomas Tanggaard; Broeng, Jes

    2011-01-01

    We investigate the effect of temperature gradients in high-power Yb-doped fiber amplifiers by a numerical beam propagation model, which takes thermal effects into account in a self-consistent way. The thermally induced change in the refractive index of the fiber leads to a thermal lensing effect...

  20. The UK High Power RF Faraday Partnership Industrial, Academia, and Public Collaboration

    Science.gov (United States)

    Phelps, A. D. R.; Carter, R. G.; Clunie, D.; Bowater, S. P.; Ellis, D.; Gamble, D.; Large, T.; Lucas, W.; Pettit, C.; Poole, M. W.; Smith, H.; Smith, P. W.; Wilcox, D. M.

    2003-12-01

    The High Power Radio Frequency (HPRF) Faraday Partnership is a UK technology forum for all users, designers, developers and researchers of RF and microwave devices and systems. High power RF and microwave engineering are key enabling technologies in a wide range of industrial sectors. Formed in October 2001 and funded initially by the UK Department of Trade and Industry and the UK Particle Physics and Astronomy Research Council, the purpose of the HPRF Faraday Partnership is the development of a vibrant research, development and manufacturing base capable of exploiting opportunities in high power radio-frequency engineering. The partnership includes the key UK industrial companies, research laboratories and university research groups. The number of partners is constantly growing and already numbers over thirty. The partnership provides the enabling technology for future high power RF systems and their power supplies through its research programme. It is training people for the sector through PhD studentships and employment as Research Associates. It is planned to develop a Masters Training program. Support and involvement in research for companies in the supply chain is provided through a Partnership Office, a web site and through a range of government funded research schemes. The HPRF Faraday Partnership is seeking to establish more long term international research and development collaborations.

  1. Abnormally High Power Output of Wind Turbine in Cold Weather: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Christophe Leclerc

    2003-01-01

    Full Text Available According to popular belief, air temperature effects on wind turbine power output are produced solely by air density variations, and power is proportional to air density. However, some cases have been reported, all involving stall-controlled wind turbines, in which unexpected high power output was observed at very low temperatures.

  2. Injecting Light of High-Power LEDs into Thin Light Guides

    NARCIS (Netherlands)

    Cornelissen, H.J.; Krijn, M.P.C.; Ma, H.; Van Sprang, H.A.

    2010-01-01

    A new method using a thin-film multilayer filter is described to couple light from high-power LEDs into a thin light guide such as an LCD backlight. Light emitted below the critical angle is reflected back to the LED and recycled. Large-angle emitted light passes the filter and is transported by

  3. Injecting light of high-power LEDs into thin light guides

    NARCIS (Netherlands)

    Cornelissen, H.J.; Ho, C.; Ma, H.; Krijn, M.P.C.M.; Van Sprang, H.A.

    2010-01-01

    A new method using a thin-film multilayer filter is described to couple light from high-power LEDs into a thin light guide such as an LCD backlight. Light emitted below the critical angle is reflected back to the LED and recycled. Largeangle emitted light passes the filter and is transported by

  4. A simple violin oscillator

    Science.gov (United States)

    Jones, R. T.

    1976-01-01

    For acoustic tests the violin is driven laterally at the bridge by a small speaker of the type commonly found in pocket transistor radios. An audio oscillator excites the tone which is picked up by a sound level meter. Gross patterns of vibration modes are obtained by the Chladni method.

  5. Oscillators and operational amplifiers

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2005-01-01

    A generalized approach to the design of oscillators using operational amplifiers as active elements is presented. A piecewise-linear model of the amplifier is used so that it make sense to investigate the eigenvalues of the Jacobian of the differential equations. The characteristic equation...

  6. Phenomenology of neutrino oscillations

    CERN Document Server

    Kobzarev, I Yu; Okun, Lev Borisovich; Shchepkin, M G

    1980-01-01

    A complete phenomenological description of neutrino oscillations is given. The most general form of the mass matrix of N types of neutrino and of the matrix of neutrino mixing in the left charged current is analyzed. Measuring the parameters of the charged current matrix in oscillatory experiments and in the experimental studies of the beta -decay electron spectra, is discussed. (20 refs).

  7. Neutrino oscillation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Camilleri, L. [European Organization for Nuclear Research, Geneva (Switzerland)

    1996-11-01

    Neutrino oscillation experiments ({nu}{sub {mu}}{yields}{nu}{sub e} and {nu}{sub {mu}}{yields}{nu}{sub {tau}}) currently being performed at accelerators are reviewed. Future plans for short and long base-line experiments are summarized. (author) 10 figs., 2 tabs., 29 refs.

  8. Proprioceptive evoked gamma oscillations

    DEFF Research Database (Denmark)

    Arnfred, Sidse M; Hansen, Lars Kai; Parnas, Josef

    2007-01-01

    to evoke gamma oscillations. EEG was recorded using 64 channels in 14 healthy subjects. In each of three runs a stimulus of 100 g load increment in each hand was presented in 120 trials. Data were wavelet transformed and runs collapsed. Inter-trial phase coherence (ITPC) was computed as the best measure...

  9. Gain media edge treatment to suppress amplified spontaneous emission in a high power laser

    Science.gov (United States)

    Hackel, Lloyd A.; Soules, Thomas F.; Fochs, Scott N.; Rotter, Mark D.; Letts, Stephan A.

    2008-12-09

    A novel method and apparatus for suppressing ASE and parasitic oscillation modes in a high average power laser is introduced. By roughening one or more peripheral edges of a solid-state crystal or ceramic laser gain media and by bonding such edges using a substantially high index bonding elastomer or epoxy to a predetermined electromagnetic absorbing arranged adjacent to the entire outer surface of the peripheral edges of the roughened laser gain media, ASE and parasitic oscillation modes can be effectively suppressed.

  10. Photonic local oscillator development

    Science.gov (United States)

    Kimberk, Robert; Tong, Edward; Hunter, Todd R.; Christensen, Robert; Blundell, Ray

    2006-12-01

    In the receiver lab, we have developed a 200 GHz to 230 GHz local oscillator constructed from mostly commercially available 1550 nm laser communication components. Theoretical and experimental work show that the laser adds negligible phase noise to this photonic local oscillator system and that spectral purity and phase stability are similar to Gunn oscillator based local oscillator output. The optical path consists of a single 1550 nm diode laser, a lithium niobate optical phase modulator, a Mach Zehnder interferometer (MZI) with a free spectral range of 75 GHz, and a 160 GHz to 260 GHz photomixer whose output is connected to a horn antenna. All of the optical devices and connections are polarization maintaining, and the photomixer was designed and fabricated at the CCLRC Rutherford Appleton Laboratory. The electrical path consists of a YIG synthesizer, operating in the frequency range 14-20 GHz, a frequency doubler, and a power amplifier connected to the RF port of the phase modulator. At the SMA on Mauna Kea, we incorporated the photonic LO into one element (Antenna 6) of a five antenna array for test observations of CO J=2-1 made towards the ultracompact HII region G138.295+1.555. Spectral features of comparable width occur on baselines with and without antenna 6, and noise increases with baseline length independent of antenna number. Continuum observations were also made toward the quasar 3c454.3 for a period of about one hour. In summary, the SMA has proven that the photonic local oscillator operates with adequate phase and frequency stability for radio-interferometry.

  11. Identifying neuronal oscillations using rhythmicity

    NARCIS (Netherlands)

    Fransen, A.M.M.; Ede, F.L. van; Maris, E.G.G.

    2015-01-01

    Neuronal oscillations are a characteristic feature of neuronal activity and are typically investigated through measures of power and coherence. However, neither of these measures directly reflects the distinctive feature of oscillations: their rhythmicity. Rhythmicity is the extent to which future

  12. High-power noise-like pulse generation using a 1.56-µm all-fiber laser system.

    Science.gov (United States)

    Lin, Shih-Shian; Hwang, Sheng-Kwang; Liu, Jia-Ming

    2015-07-13

    We demonstrated an all-fiber, high-power noise-like pulse laser system at the 1.56-µm wavelength. A low-power noise-like pulse train generated by a ring oscillator was amplified using a two-stage amplifier, where the performance of the second-stage amplifier determined the final output power level. The optical intensity in the second-stage amplifier was managed well to avoid not only the excessive spectral broadening induced by nonlinearities but also any damage to the device. On the other hand, the power conversion efficiency of the amplifier was optimized through proper control of its pump wavelength. The pump wavelength determines the pump absorption and therefore the power conversion efficiency of the gain fiber. Through this approach, the average power of the noise-like pulse train was amplified considerably to an output of 13.1 W, resulting in a power conversion efficiency of 36.1% and a pulse energy of 0.85 µJ. To the best of our knowledge, these amplified pulses have the highest average power and pulse energy for noise-like pulses in the 1.56-µm wavelength region. As a result, the net gain in the cascaded amplifier reached 30 dB. With peak and pedestal widths of 168 fs and 61.3 ps, respectively, for the amplified pulses, the pedestal-to-peak intensity ratio of the autocorrelation trace remains at the value of 0.5 required for truly noise-like pulses.

  13. Air-clad chirally-coupled-core Yb-fiber femtosecond oscillator with >10W average power

    Directory of Open Access Journals (Sweden)

    Ma Xiuquan

    2013-03-01

    Full Text Available We demonstrate high-power (> 10 W, 300-fs mode-locked oscillators at 83-MHz repetition rate using air-clad Chirally-Coupled-Core Yb-fiber with 37-µm central-core diameter, corresponding to a 30-µm mode-field-diameter.

  14. Automatically tunable continuous-wave optical parametric oscillator for high-resolution spectroscopy and sensitive trace-gas detection

    NARCIS (Netherlands)

    Ngai, A.K.Y.; Persijn, S.T.; Basum, G. von; Harren, F.J.M.

    2006-01-01

    We present a high-power (2.75 W), broadly tunable (2.75-3.83 mu m) continuous-wave optical parametric oscillator based on MgO-doped periodically poled lithium niobate. Automated tuning of the pump laser, etalon and crystal temperature results in a continuous wavelength coverage up to 450 cm(-1) per

  15. Bimodal oscillations in nephron autoregulation

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Pavlov, A.N.; Mosekilde, Erik

    2002-01-01

    The individual functional unit of the kidney (the nephron) displays oscillations in its pressure and flow regulation at two different time scales: fast oscillations associated with a myogenic dynamics of the afferent arteriole, and slower oscillations arising from a delay in the tubuloglomerular...

  16. Spectral linewidths of Josephson oscillators

    DEFF Research Database (Denmark)

    Salerno, M; Samuelsen, Mogens Rugholm; Yulin, AV

    2001-01-01

    We show that the linewidth of a Josephson flux-flow oscillator has the same functional dependence on temperature, static, and dynamic resistances as the ones of Josephson single-fluxon oscillators and small Josephson junctions. This suggests a universal formula for the linewidth of Josephson...... oscillators....

  17. Phase locking of a 275 W high power all-fiber amplifier seeded by two categories of multi-tone lasers.

    Science.gov (United States)

    Wang, Xiaolin; Leng, Jingyong; Zhou, Pu; Du, Wenbo; Xiao, Hu; Ma, Yanxing; Dong, Xiaolin; Xu, Xiaojun; Liu, Zejin; Zhao, Yijun

    2011-04-11

    Multi-tone radiation is a promising technique to suppress stimulated Brillouin scattering (SBS) effects and improve the ultimate output power of the fiber laser/amplifier. Coherent beam combining of fiber lasers/ amplifiers is another feasible way to increase the output laser power from single gain medium while simultaneously maintaining good beam quality. In this paper, we combine the multi-tone driven all-fiber amplifiers and active phase compensation to demonstrate high power phase locking for coherent beam combining. First, we present the theory of coherent beam combining of multi-tone lasers. Second, we optimize the all-fiber power amplifier oscillator power-amplifier (MOPA) system with high scalability and flexibility based on compact, high efficiency Yb-doped fiber amplifier chains. Then, two categories of multi-tone master oscillators are used to driven the amplifier chains. The first category is two coupled single-frequency lasers and the second is a frequency modulated single-frequency laser. The output powers are all boosted to 275 W without any distinct SBS. Last, phase locking of the amplifier chains are implemented using stochastic parallel gradient descent (SPGD) algorithm. Scaling this configuration to a higher power involves increasing the power per chain and adding the number of amplifier channels. © 2011 Optical Society of America

  18. Research on Gyrotrons.

    Science.gov (United States)

    1985-04-15

    Distribution Function 19 je(k): Induced Current 24 Pn(k): Source Term 28 Bean Spread Effect 32 V. INVERSE LAPLACE TRANSFORMATION 35 Fields 36 Power Flow ...work is discussed. - I -4- II. LINEARIZED VLASOV EQUATION Consider that a hollow anular electron beam (such as from a magnetron injec- tion gun) is...to the induced current J (k). The normali- zation factor CN in (4.5) defined by (3.16) is related to the total power flow throughout the waveguide

  19. Nonlinear (Anharmonic Casimir Oscillator

    Directory of Open Access Journals (Sweden)

    Habibollah Razmi

    2011-01-01

    Full Text Available We want to study the dynamics of a simple linear harmonic micro spring which is under the influence of the quantum Casimir force/pressure and thus behaves as a (an nonlinear (anharmonic Casimir oscillator. Generally, the equation of motion of this nonlinear micromechanical Casimir oscillator has no exact solvable (analytical solution and the turning point(s of the system has (have no fixed position(s; however, for particular values of the stiffness of the micro spring and at appropriately well-chosen distance scales and conditions, there is (are approximately sinusoidal solution(s for the problem (the variable turning points are collected in a very small interval of positions. This, as a simple and elementary plan, may be useful in controlling the Casimir stiction problem in micromechanical devices.

  20. Entanglement in neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Blasone, M.; Dell' Anno, F.; De Siena, S.; Illuminati, F. [Universita degli Studi di Salerno Via Ponte don Melillon, Dipt. di Matematica e Informatica, Fisciano SA (Italy); INFN Sezione di Napoli, Gruppo collegato di Salerno - Baronissi SA (Italy); Dell' Anno, F.; De Siena, S.; Illuminati, F. [CNR-INFM Coherentia - Napoli (Italy); Blasone, M. [ISI Foundation for Scientific Interchange, Torino (Italy)

    2009-03-15

    Flavor oscillations in elementary particle physics are related to multimode entanglement of single-particle states. We show that mode entanglement can be expressed in terms of flavor transition probabilities, and therefore that single-particle entangled states acquire a precise operational characterization in the context of particle mixing. We treat in detail the physically relevant cases of two- and three-flavor neutrino oscillations, including the effective measure of CP violation. We discuss experimental schemes for the transfer of the quantum information encoded in single-neutrino states to spatially delocalized two-flavor charged-lepton states, thus showing, at least in principle, that single-particle entangled states of neutrino mixing are legitimate physical resources for quantum information tasks. (authors)