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Sample records for 150kw cw power

  1. Photovoltaic concentrator application experiment, Phase I: a 150 KW photovoltaic concentrator power system for load-center applications with feedback into the utility grid. Final report, June 1, 1978--March 31, 1979

    Noel, G T; Alexander, G; Stember, L H; Stickford, G H; Smail, H E; Broehl, J H; Carmichael, D C

    1979-04-01

    A 150-kW-peak concentrator-type photovoltaic power system to supply a multiple building load application in the Columbus, Ohio area was designed and analyzed by a Battelle-led team. The system will operate in parallel with the utility grid (which provides backup power) to supply either or both of two service/commercial buildings and will feed surplus power into the utility grid. The array consists of fifteen 10-kW carousel-mounted subarrays which are two-axis tracking. The subarrays each consist of 40 passively cooled concentrating modules which incorporate a primary parabolic trough reflector and a secondary compound-elliptic concentrator to achieve a geometric concentration ratio of approx. 26. The power conditioning subsystem is microprocessor controlled, with maximum-power-point tracking and automatic control capabilities. The system performance analysis indicates that the system will supply approximately 147,000 kWh/year to the primary load and an additional 55,000 kWh/year to the utility grid, in the single-load operational mode. The system design and the daily and seasonal match of system output with the load are described in detail. Plans are also discussed for installation and for operational evaluations of performance, economics, and institutional issues.

  2. 29 W High Power CW Supercontinuum Source

    Cumberland, B A; Popov, S V; Taylor, J R

    2008-01-01

    A 29 W CW supercontinuum spanning from 1.06 to 1.67 um is generated in a short length of PCF with two zero dispersion wavelengths. The continuum has the highest spectral power density, greater than 50 mW/nm up to 1.4 um, reported to date. The use of a short length of PCF enables the continuum to expand beyond the water loss at 1.4 um. The dynamics of the continuum evolution are studied experimentally and numerically with close attention given to the effects of the water loss and the second zero dispersion wavelength.

  3. Splitting of high power, cw proton beams

    Facco, Alberto; Berkovits, Dan; Yamane, Isao

    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.

  4. Advanced pulsed and CW high-power fiber lasers

    Nilsson, J.; Grudinin, A.B.; Turner, P.W.

    2000-01-01

    We examine design issues for high-energy pulsed as well as for high-power cw fiber lasers. Power handling and pump scalability are primary issues for kilowatt fiber lasers. Special core designs are needed for high-energy pulse generation.

  5. Cascaded combiners for a high power CW fiber laser

    Tan, Qirui; Ge, Tingwu; Zhang, Xuexia; Wang, Zhiyong

    2016-02-01

    We report cascaded combiners for a high power continuous wave (CW) fiber laser in this paper. The cascaded combiners are fabricated with an improved lateral splicing process. During the fusing process, there is no stress or tension between the pump fiber and the double-cladding fiber. Thus, the parameters of the combiner are better than those that have been reported. The coupling efficiency is 98.5%, and the signal insertion loss is 1%. The coupling efficiency of the cascaded combiners is 97.5%. The pump lights are individually coupled into the double-cladding fiber via five combiners. The thermal effects cannot cause damage to the combiners and the cascaded combiners can operate stably in high power CW fiber lasers. We also develop a high power CW fiber laser that generates a maximum 780 W of CW signal power at 1080 nm with 71% optical-to-optical conversion efficiency. The fiber laser is pumped via five intra-cavity cascaded combiners and five extra-cavity cascaded combiners with a maximum pump power of 1096 W and a pump wavelength of 975 nm.

  6. Power-cancellation of CW-complexes with few cells

    Llerena, Irene

    1992-01-01

    In this paper, we use the fact that the rings of integer matrices have the power-substitution property in order to obtain a powercancellation property for homotopy types of CW-complexes with one cell in dimensions 0 and 4n and a finite number of cells in dimension 2n.

  7. IOT RF Power Sources for Pulsed and CW Linacs

    Bohlen, H P

    2004-01-01

    For many years, klystrons have been the preferred RF power amplifiers for both pulsed and CW linacs at UHF and higher frequencies. Their properties have earned them that position. But in recent years in UHF terrestrial television transmitters the earlier predominant klystron has been replaced the Inductive Output Tube (IOT) because the IOT provides higher efficiency and, due to its excellent linearity, can handle the simultaneous amplification of both the vision and the sound signal. Its robustness and life expectancy equals that of a klystron, and it more than compensates its lower gain by a lower price and a smaller size. For linac operation, derivates of UHF TV IOTs, capable of up to 80 kW CW output power, are already available and operating. In L-Band, they are presently joined by recently developed 15 to 30 kW CW IOTs. HOM-IOTs are expected to extend the CW range in UHF to 1 MW and beyond. Pulsed operation of an IOT can be achieved without a high-voltage modulator. Since the beam current is grid-controll...

  8. Variable Power, Short Microwave Pulses Generation using a CW Magnetron

    CIUPA, R.

    2011-05-01

    Full Text Available Fine control of microwave power radiation in medical and scientific applications is a challenging task. Since a commercial Continuous Wave (CW magnetron is the most inexpensive microwave device available today on the market, it becomes the best candidate for a microwave power generator used in medical diathermy and hyperthermia treatments or high efficiency chemical reactions using microwave reactors as well. This article presents a new method for driving a CW magnetron with short pulses, using a modified commercial Zero Voltage Switching (ZVS inverter, software driven by a custom embedded system. The microwave power generator designed with this method can be programmed for output microwave pulses down to 1% of the magnetron's power and allows microwave low frequency pulse modulation in the range of human brain electrical activity, intended for medical applications. Microwave output power continuous control is also possible with the magnetron running in the oscillating area, using a dual frequency Pulse Width Modulation (PWM, where the low frequency PWM pulse is modulating a higher resonant frequency required by the ZVS inverter's transformer. The method presented allows a continuous control of both power and energy (duty-cycle at the inverter's output.

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

    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.

  10. The propagation of high power CW scanning electron beam in air

    The question of propagation of high power electron beam in air presents the scientific and applied interests. The high power (80 kW) CW electron accelerator 'Rhodotron' with kinetic energy of electrons 5 and 10 MeV was used in the experiments. The experimental results for propagation of scanning electron beams in air are presented and discussed

  11. A High-power 650 MHz CW Magnetron Transmitter for Intensity Frontier Superconducting Accelerators

    Kazakevich, Grigory; Flanagan, Gene; Johnson, Rolland; Marhauser, Frank; Neubauer, Michael; Treado, Todd; Yakovlev, Vyacheslav P.; Chase, Brian; Nagaitsev, Sergei; Pasquinelli, Ralph J.

    2013-01-01

    A concept of a 650 MHz CW magnetron transmitter with fast control in phase and power, based on two-stage injection-locked CW magnetrons, has been proposed to drive Superconducting Cavities (SC) for intensity-frontier accelerators. The concept is based on a theoretical model considering a magnetron as a forced oscillator and experimentally verified with a 2.5 MW pulsed magnetron. To fulfill fast control of phase and output power requirements of SC accelerators, both two-stage injection-locked ...

  12. 808-nm fiber coupled module with a CW output power up to 130 W

    Xiaowei Wang; Xiaoyu Ma; Gaozhan Fang; Xiaoming Feng; Suping Liu

    2007-01-01

    A fiber coupled module is fabricated with integrating the emitting light from four laser diode bars into multimode fiber bundle. The continuous wave (CW) output power of the module is about 130 W with a coupling efficiency of around 80%. The output power is very stable after the temperature cycling and vibration test. No apparent power decrease has been observed as the device working continuously for 500 h.

  13. CW 100MW microwave power transfer in space

    Takayama, K. (Houston Univ., TX (United States). Inst. for Beam Particle Dynamics National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan) Texas Accelerator Center, The Woodlands, TX (United States)); Hiramatsu, S. (National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)); Shiho, M. (Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan))

    1991-01-01

    A proposal is made for high-power microwave transfer in space. The concept consists in a microwave power station integrating a multistage microwave free-electron laser and asymmetric dual-reflector system. Its use in space is discussed. 9 refs., 2 figs., 1 tab.

  14. The design and performance of CW and pulsed power couplers - A review

    Garvey, T.

    2005-01-01

    The design of input power couplers represents one of the most important challenges of accelerators that use super-conducting RF technology. These devices must fulfil several functions while being subject to mechanical, electromagnetic, vacuum and cryogenic constraints. The rapidly increasing number of projects, planned or under construction, which propose to use super-conducting cavities has prompted developments in power couplers for both CW and pulsed applications. Amongst the projects for ...

  15. High-power CW LINAC for food irradiation

    The continuing high profile food poisoning incidents are beginning to attract food processors using electron and γ-ray sterilization technologies. The present method of choice uses radioactive isotopes but high-power electron particle accelerators are proving an increasingly attractive alternative. We are developing a family of compact industrial continuous wave linear accelerators which produce electrons with energies from 600 keV in increments of ∼600 keV and with beam power of 30 kW increasing in increments of 30 kW. Here, we describe the performance of our 1st section that accelerates 15 keV gun electrons to relativistic energies and then we sketch the design of the less demanding subsequent sections that we are now constructing

  16. 1.2-MW CW high-power klystron for accelerator

    A super power CW klystron was developed for TRISTAN accelerator at National Laboratory of High Energy Physics, Japan. The klystron can deliver 1.2 MW at 508.6 MHz with an efficiency of 62 % and a gain of 54 DB. The collector is vapor-cooled and the output window is a 152D coaxial disk type. A TiN coating on the output window is a key technique to suppress multipactoring discharge of the window. (author)

  17. RF couplers for normal-conducting photoinjector of high-power CW FEL

    Kurennoy, S. (Sergey)

    2004-01-01

    A high-current emittance-compensated RF photoinjector is a key enabling technology for a high-power CW FEL. A preliminary design of a normal-conducting, 2.5-cell pi-mode, 700-MHz CW RF photoinjector that will be built for demonstration purposes, is completed. This photoinjector will be capable of accelerating a 100-mA electron beam (3 nC per bunch at 35 MHz bunch repetition rate) to 2.7 MeV while providing an emittance below 7 mm-mrad at the wiggler. More than 1 MW of RF power will be fed into the photoinjector cavity through two ridge-loaded tapered waveguides. The waveguides are coupled to the cavity by 'dog-bone' irises cut in a thick wall. Due to CW operation of the photoinjector, the cooling of the coupler irises is a rather challenging thermal management project. This paper presents results of a detailed electromagnetic modeling of the coupler-cavity system, which has been performed to select the coupler design that minimizes the iris heating due to RF power loss in its walls.

  18. Method And System For Examining Biological Materials Using Low Power Cw Excitation Raman Spectroscopy.

    Alfano, Robert R. (Bronx, NY); Wang, Wubao (Flushing, NY)

    2003-05-06

    A method and system for examining biological materials using low-power cw excitation Raman spectroscopy. A low-power continuous wave (cw) pump laser beam and a low-power cw Stokes (or anti-Stokes) probe laser beam simultaneously illuminate a biological material and traverse the biological material in collinearity. The pump beam, whose frequency is varied, is used to induce Raman emission from the biological material. The intensity of the probe beam, whose frequency is kept constant, is monitored as it leaves the biological material. When the difference between the pump and probe excitation frequencies is equal to a Raman vibrational mode frequency of the biological material, the weak probe signal becomes amplified by one or more orders of magnitude (typically up to about 10.sup.4 -10.sup.6) due to the Raman emission from the pump beam. In this manner, by monitoring the intensity of the probe beam emitted from the biological material as the pump beam is varied in frequency, one can obtain an excitation Raman spectrum for the biological material tested. The present invention may be applied to in the in vivo and/or in vitro diagnosis of diabetes, heart disease, hepatitis, cancers and other diseases by measuring the characteristic excitation Raman lines of blood glucose, cholesterol, serum glutamic oxalacetic transaminase (SGOT)/serum glutamic pyruvic transaminase (SGPT), tissues and other corresponding Raman-active body constituents, respectively.

  19. Dismantling nuclear power plant with new industrial cw ND:YAG high power lasers

    Dismantling is a great challenge for nuclear companies which are facing with the cleaning of former nuclear sites. Among the available cutting processes is the multi-kilowatts laser whose power is transmitted through optical fibers. Unlike other cutting processes such as the plasma arc cutting process or the oxy-fuel cutting process, the laser process can be easily implemented by robotic equipments. The mechanised robotic arm carries a laser cutting head to perform, with remote-controlled equipments, the cutting operation. In order to insure the civil and defense clean up program, the CEA dismantling division support an R and D program for industrialize the laser process for their applications with their specific conditions of used, and risk management. The present study deals with the performances which can be reached with high power cw ND:YAG lasers. The cutting tests were carried out up to 8 kW. The laser power was delivered through a specific power supply chain: a 0,4 mm fiber was transporting the power from the laser to a first interface (coupler) then a second 0,6 mm fiber was bringing the laser power to the cutting head. This solution allowed a power delivery chain whose length could be as high as 100 + 20/50 m. Another advantage of this kind of power supply is that the first fiber can be set in a non contaminated environment whereas the second fiber lies in the contaminated area. The cutting head used for these tests was a specific tool developed for this laser dismantling work: it is a laser cutting head cooled by pressurized air. This tool was developed with the requirement to be able to sustain a laser power of 14 kW. The pressurized air used to cool the head is also used as cutting gas. The cutting capability was about 10 mm by kW, we have achieved cutting an austenitic steel plate of thickness 100 mm. These performances were reached with the cut started on the plate's edge. If the cut started in the middle of the plate, the cutting performances were

  20. Dismantling nuclear power plant with new industrial cw ND:YAG high power lasers

    Chagnot, Christophe; Dinechin, Guillaume de; Canneau, Gaetan [CEA, DEN, DM2S, SEMT, LTA, F-91191 Gif-sur-Yvette (France); Idasiak, Jean-Marc [CEA, DEN, SDTC, 30207 Bagnols-sur-Ceze (France)

    2009-06-15

    Dismantling is a great challenge for nuclear companies which are facing with the cleaning of former nuclear sites. Among the available cutting processes is the multi-kilowatts laser whose power is transmitted through optical fibers. Unlike other cutting processes such as the plasma arc cutting process or the oxy-fuel cutting process, the laser process can be easily implemented by robotic equipments. The mechanised robotic arm carries a laser cutting head to perform, with remote-controlled equipments, the cutting operation. In order to insure the civil and defense clean up program, the CEA dismantling division support an R and D program for industrialize the laser process for their applications with their specific conditions of used, and risk management. The present study deals with the performances which can be reached with high power cw ND:YAG lasers. The cutting tests were carried out up to 8 kW. The laser power was delivered through a specific power supply chain: a 0,4 mm fiber was transporting the power from the laser to a first interface (coupler) then a second 0,6 mm fiber was bringing the laser power to the cutting head. This solution allowed a power delivery chain whose length could be as high as 100 + 20/50 m. Another advantage of this kind of power supply is that the first fiber can be set in a non contaminated environment whereas the second fiber lies in the contaminated area. The cutting head used for these tests was a specific tool developed for this laser dismantling work: it is a laser cutting head cooled by pressurized air. This tool was developed with the requirement to be able to sustain a laser power of 14 kW. The pressurized air used to cool the head is also used as cutting gas. The cutting capability was about 10 mm by kW, we have achieved cutting an austenitic steel plate of thickness 100 mm. These performances were reached with the cut started on the plate's edge. If the cut started in the middle of the plate, the cutting performances

  1. Analysis of RF section of 250 kW CW C-Band high power klystron

    Klystron is a microwave tube which is used as a power amplifier in various applications like radar, particle accelerators and thermonuclear reactors. The paper deals with the analysis of RF section of 250 kW CW C band high power klystron for 50 to 60 kV beam voltage The simulation is done using Poisson's superfish and AJ disk software's Design of cavity is done using superfish. The result of superfish is used to decide the dimensions of the geometry of the cavity and AJ disk is used to determined the centre to centre distances between the cavities in order to obtain the desired powers. (author)

  2. Development of a high power VHF CW transmitter for RIB programme

    SAMEER has been entrusted with the responsibility of developing a high power VHF MOPA transmitter for use in the RIB programme of VECC, Kolkata.The transmitter is capable of operating in both CW and pulsed RF mode. Low power RF subsystems, such as level controller and phase controller, ensure smooth control and good stability over power level and relative phase of the output signal. As, at a future date, multiple transmitters are to be operated using the same stable source, phase control of individual transmitter is absolutely essential

  3. A low-power CMOS trans-impedance amplifier for FM/cw ladar imaging system

    Hu, Kai; Zhao, Yi-qiang; Sheng, Yun; Zhao, Hong-liang; Yu, Hai-xia

    2013-09-01

    A scannerless ladar imaging system based on a unique frequency modulation/continuous wave (FM/cw) technique is able to entirely capture the target environment, using a focal plane array to construct a 3D picture of the target. This paper presents a low power trans-impedance amplifier (TIA) designed and implemented by 0.18 μm CMOS technology, which is used in the FM/cw imaging ladar with a 64×64 metal-semiconductor-metal(MSM) self-mixing detector array. The input stage of the operational amplifier (op amp) in TIA is realized with folded cascade structure to achieve large open loop gain and low offset. The simulation and test results of TIA with MSM detectors indicate that the single-end trans-impedance gain is beyond 100 kΩ, and the -3 dB bandwidth of Op Amp is beyond 60 MHz. The input common mode voltage ranges from 0.2 V to 1.5 V, and the power dissipation is reduced to 1.8 mW with a supply voltage of 3.3 V. The performance test results show that the TIA is a candidate for preamplifier of the read-out integrated circuit (ROIC) in the FM/cw scannerless ladar imaging system.

  4. 2-kW Average Power CW Phase-Conjugate Solid-State Laser

    Zakharenkov, Yuri A.; Clatterbuck, Todd O.; Shkunov, Vladimir V.; Betin, Alexander A.; Filgas, David M.; Ostby, Eric P.; Strohkendl, Friederich P.; Rockwell, David A.; Baltimore, Robert S.

    2007-01-01

    We have demonstrated stable operation of a 2-kW Yb:YAG phase-conjugate master oscillator power amplifier (PC-MOPA) laser system with a loop phase-conjugate mirror (LPCM). This is the first demonstration of a continuous wave (CW)-input LPCM MOPA operating at a power greater than 1 kW with a nearly diffraction-limited output beam. The single-pass beam quality incident on the LPCM varied with the specific operating conditions, but it was typically ${sim}20$ times diffraction-limited (XDL). The m...

  5. Advances in high power calorimetric matched loads for short pulses and CW gyrotrons

    The development of high power gyrotrons for plasma physics research needs properly matched calorimetric loads able to absorb and measure the power, which nowadays is foreseen to be as high as 2 MW during CW operations. To this end IFP/CNR has developed a family of matched loads useful in the mm-wave frequency band for applications ranging from a few ms to CW in pulse length. The different loads in the family, made of an integrating sphere with a partially reflecting coating on the inner wall, are characterized by having the same absorbing geometry for the incoming beam and a different heat removal system for the specific application. Some important advances have been recently achieved from the point of view of the uniformity of power distribution on the absorbing wall and of the load construction. With the high precision achieved in the coating thickness a better control of the heating power distribution is possible by proper shaping of the local reflectivity, in addition to the shaping of the mirror dispersing the input beam. A more sophisticated model describing the power distribution has been developed, taking into account a variable thickness of the absorbing coating, the proper shape of the spreading mirror, the frequency of the incoming radiation and the shape of the input beam. Lower coating thickness is shown to be preferable, for a given local reflectivity, from the point of view of a lower peak temperature and thermal stress. The paper describes a load with variable coating thickness along the meridian of the sphere, showing a uniform power deposition on the inner walls. The cooling pipe is completely electroformed on the spherical copper shell, ensuring the maintenance of the correct curvature of the inner surface and fast heat conduction from the absorbing coating to the water through the thin copper body. For CW use all heated parts of the load must be cooled and this is achieved with 16 electroformed spiral channels. Both short pulse loads (0.1-1 s

  6. Advances in High Power Calorimetric Matched Loads for Short Pulses and CW Gyrotrons

    The development of high power gyrotrons for plasma physics research needs proper matched and calorimetric loads able to absorb and measure the power, which nowadays is foreseen to be as high as 2 MW during CW operations. To this end IFP/CNR has developed a family of matched loads useful in the mm-wave frequency band for applications ranging from a few ms to CW in pulse length. The different loads in the family, made of an integrating sphere with a partially reflecting coating on the inner wall, are characterized by having the same absorbing geometry for the incoming beam and a different heat removal system for the specific application. Some important advances have been recently achieved from the point of view of the uniformity of power distribution on the absorbing wall and of the load construction. With high precision achieved in the coating thickness a better control of the heating power distribution is possible by proper shaping of the local reflectivity, in addition to the shaping of the mirror dispersing the input beam. A more sophisticated model describing the power distribution has been developed, taking into account a variable thickness of the absorbing coating, the proper shape of the spreading mirror, the frequency of the incoming radiation and the shape of the input beam. Lower coating thickness is shown to be preferable, at equal local reflectivity, from the point of view of a lower peak temperature and thermal stress. The paper describes a load with variable coating thickness along the meridian of the sphere, showing a uniform power deposition on the inner walls. The cooling pipe is completely electroformed on the spherical copper shell, ensuring the maintenance of the correct curvature of the inner surface and a fast heat conduction from the absorbing coating to the water through the thin copper body. For CW use all heated parts of the load must be cooled and this is achieved by 16 electroformed spiral channels. Both short pulse loads (0.1-1 s) and

  7. New Class of CW High-Power Diode-Pumped Alkali Lasers (DPALs)

    Krupke, W F; Beach, R J; Kanz, V K; Payne, S A; Early, J T

    2004-03-23

    The new class of diode-pumped alkali vapor lasers (DPALs) offers high efficiency cw laser radiation at near-infrared wavelengths: cesium 895 nm, rubidium 795 nm, and potassium 770 nm. The working physical principles of DPALs will be presented. Initial 795 nm Rb and 895 nm Cs laser experiments performed using a titanium sapphire laser as a surrogate pump source demonstrated DPAL slope power conversion efficiencies in the 50-70% range, in excellent agreement with device models utilizing only literature spectroscopic and kinetic data. Using these benchmarked models for Rb and Cs, optimized DPALs with optical-optical efficiencies >60%, and electrical efficiencies of 25-30% are projected. DPAL device architectures for near-diffraction-limited power scaling into the high kilowatt power regime from a single aperture will be described. DPAL wavelengths of operation offer ideal matches to silicon and gallium arsenide based photovoltaic power conversion cells for efficient power beaming.

  8. Performance of 170 GHz high-power gyrotron for CW operation

    A quasi-steady-state oscillation of 100 s with 0.5 MW power level was demonstrated on a 170 GHz ITER gyrotron. The temperature of major components of the gyrotron reached the steady state, which gives a prospect for a 1 MW-CW, 170 GHz ITER gyrotron. For a further pulse extension and power increase, the gyrotron and its control system have been modified; i.e. a built-in radiator has been optimized for improvement of an efficiency of gyrotron output power and reduction of stray radiation, and pre-program controls of a cathode heater power, magnetic field at the cavity and voltage between anode and cathode, have been employed for stabilization of the beam current and the output power. (author)

  9. High-power CW tunable solid state dye lasers: from the visible to UV

    Bornemann, R.; Thiel, E.; Haring Bolívar, P.

    2012-06-01

    We describe a high power CW solid-state dye laser setup. With perylene orange in PMMA as gain medium an output power up to 800 mW at 576 nm and a tuning range between 565 and 595 nm is reached. The laser output shows good long time power stability. The durability can be adjusted by variation of the pump power. A feedback loop controls the laser output. At a setpoint of e.g. 100 mW, the laser output can be provided for more than eight hours with a low noise level (RMS BBO (Beta-Barium Borate) crystal is used. The UV laser radiation can be tuned over 10 nm. The theoretical limit of UV output is estimated to 3.5 mW. To our knowledge we present the first tunable CW polymer UV laser. While the output stability at the fundamental wavelength is reasonably good, in the UV region a significant enhancement of the noise level is observed. In addition to this the long time stability is reduced to few minutes. The limitation is mainly given by the photo-decomposition of the organic dye molecules.

  10. Development of high power CW 3.7 GHz klystrons for fusion experiments on Tore Supra

    Magne, R.; Armitano, A.; Berger-By, G.; Bouquey, F.; Corbel, E.; Delpech, L.; Mollard, P.; Prou, M.; Samaille, F.; Volpe, D., E-mail: roland.magne@cea.fr [CEA, IRFM, F-13108 St Paul-lez-Durance (France); Beunas, A. [Thales Electron Devices, 2 rue M. Dassault, F-78414 Veelizy-Villacoublay (France); Kazarian, F. [ITER Organization, F-i 3115 St Paul-lez-Durance (France)

    2011-07-01

    In the frame of the CIMES project, a collaborative effort between Association Euratom-CEA and Thales Electron Devices (TED) has led to the development of a high power CW klystron TH 2103 C, working at 3.7 GHz, for plasma heating and current drive for the Tokamak Tore Supra. A prototype has been manufactured and thoroughly tested on water load in December 2007 to verify that all the parameters met the specifications. The paper will present in detail the process and results of the test of the klystrons.

  11. DPAL: A New Class of Lasers for CW Power Beaming at Ideal Photovoltaic Cell Wavelengths

    Krupke, W F; Beach, R J; Payne, S A; Kanz, V K; Early, J T

    2003-09-15

    The new class of diode pumped alkali vapor lasers (DPALs) offers high efficiency cw laser beams at wavelengths which efficiently couple to photovoltaic (PV) cells: silicon cells at 895 nm (cesium), and GaAs cells at 795 nm (rubidium) and at 770 nm (potassium). DPAL electrical efficiencies of 25-30% are projected, enabling PV cell efficiencies {approx}40% (Si) and {approx}60% (GaAs). Near-diffraction-limited DPAL device power scaling into the multi-kilowatt regime from a single aperture is projected.

  12. Two-photon excitation in living cells induced by low-power cw laser beams

    Koenig, Karsten; Krasieva, Tatiana B.; Liu, Yagang; Berns, Michael W.; Tromberg, Bruce J.

    1996-05-01

    We demonstrate multi-photon excitation in optically-trapped living cells. Intracellular non- resonant two-photon excitation of endogenous and exogenous chromophores was induced by CW near infrared (NIR) trapping beams of 105 mW power. In the case of fluorescent chromophores, detection of NIR-excited visible fluorescence was achieved by imaging and spectroscopy methods. Trap-induced, two-photon excited fluorescence was employed as a novel diagnostic method to monitor intracellular redox state and cell vitality of single motile spermatozoa and Chinese hamster ovary cells. We found, that nonlinear absorption of NIR photons NIR, single-frequency traps (`optical tweezers') for micromanipulation of vital cells.

  13. High power CW diode-side-pumped Nd:YAG rod laser

    Hailin Wang(王海林); Weiling Huang(黄维玲); Zhuoyou Zhou(周卓尤); Hongbing Cao(曹红兵)

    2003-01-01

    We report on the characterization of a diode-side-pumped Nd:YAG rod laser operating at high CW output power. A four-fold pump configuration is designed and the pump light is directly coupled into the Nd:YAG rod without the help of any cylindrical lenses. The distribution of pump light in the Nd:YAG rod has been calculated by using ray tracing program. The thermal lens effect of the Nd:YAG rod has been experimentally measured. A maximum output power of 800 W at 1064 nm in multimode operation is obtained for a pump power of 2400 W with 33% optical-optical efficiency. At the same time, the maximum beam parameter product of 25 mm.mrad is achieved.

  14. Critical power of keyhole formation in CW Nd:YAG laser deep penetration welding

    Qin Guoliang; Qi Xiukun; Lin Shangyang

    2007-01-01

    The energy model was founded to calculate the critical power of keyhole formation by using the limit principle in CW (continuous wave) Nd:YAG laser deep penetration welding process. The model was validated by experiments. The results show that there are two errors between the calculated critical power of keyhole formation and that of experiments: one is that the calculated results is less than those of experiments, which is caused by not considering the energy loss by heat conduction in the model of keyhole formation. The other is that there is 0.9 mm error between the axis of the calculated curve of critical power with location of laser focus and that of experimental curve, which is induced by the excursion of laser focus in laser deep penetration welding. At last, the two errors were revised according to the analyses of the errors.

  15. High power CW and Q-switched operation of a diode-side-pumped Nd: YAG 1319-nm laser

    Yunfang Wan; Kezhen Han; Yun Wang; Jingliang He

    2008-01-01

    We demonstrated the highly efficient continuous wave(CW)and Q-switched infrared laser from a diodeside-pumped Nd:YAG crystal.A CW output as high as 66 W at 1319 nm was achieved under the pump power of 460 W,corresponding to a coversion efficiency of 14.3%.A maximum average power of 8.9 W of TEM00 mode was obtained in Q-switched operation at the repetition rate of 8 kHz.The performance of the laser considering the thermal lens effect induced by pump power Was also analyzed.

  16. RF power upgrade at the superconducting 1.3 GHz CW LINAC "ELBE" with solid state amplifiers

    Büttig, Hartmut; Arnold, A.; Büchner, A.; Justus, M.; Kuntsch, M.; Lehnert, U.; Michel, P.; Schurig, R.; Staats, G.; Teichert, J.

    2013-03-01

    The RF power for the superconducting 1.3 GHz CW LINAC "ELBE" has been doubled from less than 10 kW to 20 kW per cavity. In January 2012 the four 10 kW klystrons used to drive the four superconducting cavities of the LINAC have been replaced by pairs of 10 kW solid state power amplifiers (SSPA). ELBE is now worldwide the first 1.3 GHz CW LINAC equipped with solid state RF power amplifiers. This technical note details on this project.

  17. Development of a powerful continuously tunable mid-infrared cw PPLN OPO for trace gas detection

    van Herpen, Maarten; te Lintel Hekkert, Sacco; Bisson, Scott E.; Harren, Frans J. M.

    2002-08-01

    A new Optical Parametric Oscillator for the mid infrared wavelength region of 3-3.8 micrometer is developed with an idler output power of more than 1 Watt. The OPO is pumped with a 10 Watt, cw, Nd:YAG Laser and consists of a bowtie ring cavity (FSR 320 MHz) resonating at the signal wavelength. The wavelength is controlled with a fan-out PPLN crystal and a low finesse intracavity Fabry-Perot. The idler output could be tuned over more than 24 Ghz modehop-free, by tuning the pump laser and keep the OPO cavity fixed. Mode hop tuning over 100 Ghz could be obtained changing the length of the intracavity Fabry-Perot. This high power OPO is combined with photoacoustic spectroscopy in order to develop a sensitive trace gas detector for LifeScience applications.

  18. Operational experience and recent upgrading of TRISTAN high power cw klystrons

    The rf system of TRISTAN MR required 525 MV to accelerate e+e-beams up to 32 GeV. This was achieved by 104 units of 9 cell APS cavities as well as 32 units of 5 cell superconducting cavities. Every 4 units is driven with a high power cw klystron which can provide rf power of 508.58 MHz up to above 800 kW. At present 34 klystrons are installed in MR, 12 of which, including 8 for superconducting cavities, are 0.8 MW/1 MW tubes and 22 of which are 1.2 MW tubes. Although the performance of the latter tube is rather very stable, some of them still suffer from unwanted instability due to pulse AM. Efforts have been continuously made to eliminate this instability. (author) 7 refs.; 5 figs

  19. Installation and test results of a high-power, CW klystrode amplifier at Los Alamos National Laboratory

    The Chalk River Laboratory (CRL) 1.25 MeV, 267 MHz CW radio frequency quadrupole (RFQ) project has been moved to Los Alamos AOT Division as a collaborative effort between Los Alamos and Chalk River Laboratories. The RF part of this project includes two 267 MHz, 0.25 MW, CW klystrode transmitters. The klystrode is a relatively new type of RF source that combines the input structure from a conventional gridded tube and the output structure of a klystron. It is widely used within the UHF television band at reduced power (60 kW at peak of sync). However, this is the first application of a high power klystrode for a particle accelerator. This paper will describe the experimental configuration at Los Alamos, provide block diagrams of the klystrode transmitter, discuss the attributes of the klystrode which make it a desirable candidate for high efficiency CW accelerators, and present relevant test results

  20. Design of spherical electron gun for ultra high frequency, CW power inductive output tube

    Kaushik, Meenu; Joshi, L. M.

    2016-03-01

    Inductive Output Tube (IOT) is an amplifier that usually operates in UHF range. It is an electron tube whose basic structure is similar to conventional vacuum devices. This device is widely used in broadcast applications but is now being explored for scientific applications also specifically, particle accelerators and fusion plasma heating purposes. The paper describes the design approach of a spherical gridded electron gun of a 500 MHz, 100 kW CW power IOT. The electron gun structure has been simulated and optimized for operating voltage and current of 40kV and 3.5 A respectively. The electromagnetic analysis of this spherical electron gun has been carried out in CST and TRAK codes.

  1. Proton Beam Verification using RF Power Measurement Data for a cw Radio Frequency Quadrupole LINAC

    Bolme, G.O.; Hardek, T.W.; Hansborough, L.D.; Hodgkins, D.J.; Keffeler, D.R.; Sherman, J.D.; Smith, H.V.; Stevens, R.R.; Young, L.M.; Zaugg, T.J.; Arvin, A.H.; Bolt, A.S.; Richards, M.C.; Balleyguier, P.P.; Kamperschroer, J.H.

    1999-03-29

    A cw radio frequency quadrupole (RFQ) LINAC section and klystrode based rf system was obtained from the Chalk River Laboratories and was recommissioned at LANL to conduct demonstration proton beam experiments in support of a spallation neutron source driver for tritium production. A variation of the Low Energy Demonstration Accelerator (LEDA) proton injector, modified to operate at 50 keV, was mated to the RFQ and was operated to support the high current (up to 100 mA), proton beam advance studies for the Accelerator Production of Tritium (APT) program. Detailed measurements and calibrations of the RFQ at both low and high power provided the corroborating data to other available beam measurements for verification of the accelerator design.

  2. RF power upgrade at the superconducting 1.3 GHz CW LINAC “ELBE” with solid state amplifiers

    Büttig, Hartmut, E-mail: buettig@hzdr.de [Radiation Source ELBE, Helmholtz Zentrum Dresden-Rossendorf (Germany); Arnold, A.; Büchner, A.; Justus, M.; Kuntsch, M.; Lehnert, U.; Michel, P.; Schurig, R.; Staats, G.; Teichert, J. [Radiation Source ELBE, Helmholtz Zentrum Dresden-Rossendorf (Germany)

    2013-03-11

    The RF power for the superconducting 1.3 GHz CW LINAC “ELBE” has been doubled from less than 10 kW to 20 kW per cavity. In January 2012 the four 10 kW klystrons used to drive the four superconducting cavities of the LINAC have been replaced by pairs of 10 kW solid state power amplifiers (SSPA). ELBE is now worldwide the first 1.3 GHz CW LINAC equipped with solid state RF power amplifiers. This technical note details on this project. -- Highlights: ► We report the first installation of 10 kW solid state RF-amplifiers at 1.3 GHz CW LINAC. ► The sc. cavities of “ELBE” are now driven by a pair of 10 kW solid state amplifiers (SSPA). ► The RF-power upgrade allows doubling the electron beam current (CW). ► Advantages of the new RF system are high reliability, easy service and lower costs.

  3. RF power upgrade at the superconducting 1.3 GHz CW LINAC “ELBE” with solid state amplifiers

    The RF power for the superconducting 1.3 GHz CW LINAC “ELBE” has been doubled from less than 10 kW to 20 kW per cavity. In January 2012 the four 10 kW klystrons used to drive the four superconducting cavities of the LINAC have been replaced by pairs of 10 kW solid state power amplifiers (SSPA). ELBE is now worldwide the first 1.3 GHz CW LINAC equipped with solid state RF power amplifiers. This technical note details on this project. -- Highlights: ► We report the first installation of 10 kW solid state RF-amplifiers at 1.3 GHz CW LINAC. ► The sc. cavities of “ELBE” are now driven by a pair of 10 kW solid state amplifiers (SSPA). ► The RF-power upgrade allows doubling the electron beam current (CW). ► Advantages of the new RF system are high reliability, easy service and lower costs

  4. SM green fiber laser operating in CW and QCW regimes and producing over 550W of average output power

    Gapontsev, Valentin; Avdokhin, Alexey; Kadwani, Pankaj; Samartsev, Igor; Platonov, Nikolai; Yagodkin, Roman

    2014-02-01

    We report a single-mode (SM) green laser based on single-pass frequency doubling of a linearly-polarized narrowlinewidth Yb fiber laser in LBO crystal, and configured to operate in a range of regimes from continuous-wave (CW) to high-repetition-rate quasi-continuous-wave (QCW). Adjusting the duty cycle, we maintained high second harmonic generation (SHG) efficiency for various output powers. Average powers of over 550W in QCW and over 350W in CW regimes were obtained with the wall-plug efficiency up to 15%, opening the possibility to creating new class of simple, compact and efficient single-mode green lasers with output power up to 1kW and above. The same approach could also be used to create high-power lasers operating at other wavelengths in ultraviolet and visible spectral ranges.

  5. The design and performance of CW and pulsed power couplers—A review

    Garvey, T.

    2006-07-01

    The design of input power couplers represents one of the most important challenges of accelerators that use super-conducting RF technology. These devices must fulfill several functions while being subject to mechanical, electromagnetic, vacuum and cryogenic constraints. The rapidly increasing number of projects, planned or under construction, which propose to use super-conducting cavities has prompted developments in power couplers for both CW and pulsed applications. Amongst the projects for which couplers have been, or are being, developed one finds VUV and X-ray free electron lasers (based on self-amplified spontaneous emission), spallation neutron sources (SNS), energy recovery linacs, and high energy colliders. We will review the design requirements and performances obtained for several of these couplers. Particular attention will be paid to the couplers which have been used on the TESLA Test Facility at DESY, the variations of this coupler which are under consideration for future synchrotron light sources and the coupler chosen for use on the SNS.

  6. Normal-conducting RF cavity of high current photoinjector for high power CW FEL.

    Kurennoy, S. (Sergey); Schrage, D. L. (Dale L.); Wood R. L. (Richard L.); Schultheiss, T. (Thomas); Rathke, J. (John); Young, L. M. (Lloyd M.)

    2004-01-01

    An RF photoinjector capable of producing high continuous average current with low emittance and energy spread is a key enabling technology for high power CW FEL. The design of a 2.5-cell, {pi}-mode, 700-MHz normal-conducting RF photoinjector cavity with magnetic emittance compensation is completed. With the electric field gradients of 7.7, and 5 MV/m in the three cells, the photoinjector will produce a 2.5-MeV electron beam with 3-nC charge per bunch and the transverse rms emittance 7 mm-mrad. Electromagnetic modeling was used extensively to optimize ridge-loaded tapered waveguides and RF couplers, which led to a new, improved coupler iris design. The results, combined with a thermal and stress analysis, show that the challenging problem of cavity cooling can be successfully solved. The manufacturing of a demo 100-mA (at 35 MHz bunch repetition rate) photoinjector is underway. The design is scalable to higher power levels by increasing the electron bunch repetition rate, and provides a path to a MW-class amplifier FEL. This paper presents the cavity design and details of RF coupler modeling.

  7. Normal conducting RF cavity of high current photoinjector for high power CW FEL.

    Kurennoy, S. (Sergey); Schrage, D. L. (Dale L.); Wood R. L. (Richard L.); Schultheiss, T. (Thomas); Rathke, J. (John); Christina, V.; Young, L. M. (Lloyd M.)

    2004-01-01

    An RF photoinjector capable of producing high continuous average current with low emittance and energy spread is a key enabling technology for high power CW FEL. The design of a 2.5-cell {pi}-mode 700-MHz normal-conducting RF photoinjector cavity with magnetic emittance compensation is completed. With the electric field gradients of 7, 7, and 5 MV/m in the three cells, the photoinjector will produce a 2.5-MeV electron beam with 3-nC charge per bunch and 7 mm-mrad transverse rms emittance. Electromagnetic modeling was used extensively to optimize ridge-loaded tapered waveguides and RF couplers, which led to a new improved coupler-iris design. The results, combined with a thermal/stress analysis, show that the challenging problem of cavity cooling can be successfully solved. A demo 100-mA (at 35-MHz bunch-repetition rate) photoinjector is being manufactured. The design is scalable to higher power levels by increasing the bunch repetition rate, and provides a path to a MW-class amplifier FEL. The cavity design and details of RF coupler modeling are presented.

  8. TTF3 power coupler thermal analysis for LCLS-II CW operation

    Xiao, L. [SLAC National Accelerator Lab., Menlo Park, CA (United States). Linac Coherent Light Source (LCLS); Adolphsen, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States). Linac Coherent Light Source (LCLS); Li, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States). Linac Coherent Light Source (LCLS); Nantista, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States). Linac Coherent Light Source (LCLS); Raubenheimer, T. [SLAC National Accelerator Lab., Menlo Park, CA (United States). Linac Coherent Light Source (LCLS); Solyak, N. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Gonin, I. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-05-13

    The TESLA 9-cell SRF cavity design has been adopted for use in the LCLS-II SRF Linac. Its TTF3 coaxial fundamental power coupler (FPC), optimized for pulsed operation in European XFEL and ILC, requires modest changes to make it suitable for LCLS-II continuous-wave (CW) operation. For LCLS-II it must handle up to 7 kW of power, fully reflected, with the maximum temperature around 450 K, the coupler bake temperature. In order to improve TTF3 FPC cooling, an increased copper plating thickness will be used on the inner conductor of the ‘warm’ section of the coupler. Also, the antenna will be shortened to achieve higher cavity Qext values. Fully 3D FPC thermal analysis has been performed using the SLAC-developed parallel finite element code suite ACE3P, which includes electromagnetic codes and an integrated electromagnetic, thermal and mechanical multi-physics code. In this paper, we present TTF3 FPC thermal analysis simulation results obtained using ACE3P as well as a comparison with measurement results.

  9. Development of power supply for 30kW CW IOT/klystron at the cERL

    The DC power supply for (CW) 30kW class RF sources, IOT (-36kV, 1.6A) and klystron (-20kV, 2.5A), has been developed. The RF sources are used to drive 1.3GHz superconducting cavities at the Compact ERL (cERL) in KEK. The details of the DC power supply are reported in this paper. (author)

  10. High-power picosecond regenerative amplifier based on CW diode side-pumped Nd:YAG with high beam quality

    Hua Lin; Jinfeng Li; Jinping He; Xiaoyan Liang

    2011-01-01

    @@ A compact high-power picosecond regenerative amplifier based on continuous wave(CW) diode sidepumped Nd:YAG is demonstrated.Average power of 8.8 W is achieved at,a repetition rate of 5 kHz at a wavelength of 1064 nm with a pulse duration of 28 ps,corresponding to a pulse energy of 1.76 mJ and a peak power of 62.9 MW.%A compact high-power picosecond regenerative amplifier based on continuous wave (CW) diode side-pumped Nd:YAG is demonstrated. Average power of 8.8 W is achieved at.a repetition rate of 5 kHz at a wavelength of 1064 nm with a pulse duration of 28 ps, corresponding to a pulse energy of 1.76 mJ and a peak power of 62.9 MW. The beam quality is close to the diffraction limit with M2x - 1.24, M2y = 1.03. To the best of our knowledge, this is the highest pulse energy obtained from a CW diode pumped Nd:YAG picosecond regenerative amplifier.

  11. Design of planar electron gun for UHF range, CW power inductive output tube

    Inductive Output Tube (lOT) is an amplifier which is now-a-days in demand for scientific applications. For every vacuum tube, electron gun is an important part and in fact considered as the heart of the tube. Hence, designing of this component is very crucial for efficient operation of the device throughout its lifetime. This paper is all about the electromagnetic (EM) design of planar electron gun of 40 kV, 3.5 A beam voltage and beam current respectively, for a 100 kW CW power lOT operating in UHF range. The design considerations and basic equations involved in its design are included in the paper. The gun structure has been optimized for getting the desired beam characteristics. The simulation results including the beam profile along with the beam current are shown using two commercial codes namely TRAK and MAGIC code. Planar shape of electron beam reduces space charge forces in the beam itself and consequently beam energy spread for a given current. The magnetic focusing of planar beam is easier comparative to spherical beam hence, this structure has been adopted for this particular device design. (author)

  12. Design of multiple ferrite tile phase shifters for applications in high CW power differential phase shift circulators

    The LHCD System of SST-1 Tokamak at IPR, Gandhinagar uses four Klystrons (TH 2103D) each supplying 500 kW power to drive the plasma current non inductively. However these tubes are often susceptible to damage due to a high VSWR. As such, circulators are employed to route the reflections to a dummy load thereby protecting the klystron from damage. Differential Phase Shift Circulators (DPSC) which are usually composed of magic tee, ferrite phase shifters and couplers are often preferred at a high CW power level over conventional junction circulators due to their higher power handling capacity. The power handling capacity of circulators is often limited by the power handling capacity of the phase shifter section. At a high CW power level, the cooling of the ferrite is of prime importance. As such it is required to have a larger contact area of the ferrite material with the waveguide so that better cooling arrangements are provided. It is thus advantageous to use multiple ferrite tiles in the phase shifter to maximize the power handling capacity of the phase shifter. This paper presents the low power prototype design of a ferrite phase shifter at 3.7 GHz to be used in the circulator of LHCD System of SST-1 tokamak. The paper also analyses the phase characteristics and the thermal power dissipation of the phase shifter with single, two and four tile ferrites along with stacked waveguides multiple ferrite tiles configuration. (author)

  13. New High Power CW Test Facilities For ITER ICRH Components Testing

    Bernard, J. M.; Lombard, G.; Argouarch, A.; Chaix, J. P.; Fejoz, P.; Garibaldi, P.; Hatchressian, J. C.; Lebourg, P.; Martinez, A.; Mollard, P.; Mouyon, D.; Mougeolle, G.; Pagano, M.; Thouvenin, D.; Volpe, D.; Volpe, R.; Vulliez, K.

    2011-12-01

    First CW test bed, devoted for Ion Cyclotron Resonance Heating (ICRH), has been built at CEA Cadarache. It has been designed for testing the ICRH antenna sub assemblies under ITER relevant conditions (vacuum, cooling and RF). This paper presents a technical overview of these facilities and discusses their future operations in the framework of the ITER ICRH European R&D program.

  14. High sustained average power cw and ultrafast Yb:YAG near-diffraction-limited cryogenic solid-state laser.

    Brown, David C; Singley, Joseph M; Kowalewski, Katie; Guelzow, James; Vitali, Victoria

    2010-11-22

    We report what we believe to be record performance for a high average power Yb:YAG cryogenic laser system with sustained output power. In a CW oscillator-single-pass amplifier configuration, 963 W of output power was measured. In a second configuration, a two amplifier Yb:YAG cryogenic system was driven with a fiber laser picosecond ultrafast oscillator at a 50 MHz repetition rate, double-passed through the first amplifier and single-passed through the second, resulting in 758 W of average power output. Pulses exiting the system have a FWHM pulsewidth of 12.4 ps, an energy/pulse of 15.2 μJ, and a peak power of 1.23 MW. Both systems are force convection-cooled with liquid nitrogen and have been demonstrated to run reliably over long time periods. PMID:21164825

  15. 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

    2002-11-01

    Development of a 100 MeV CW proton LINAC has been planned at CAT. This LINAC will be needing CW rf power in the frequency ranges of 350 MHz and 700 MHz for its RFQ and DTL/CCDTL/SFDTL structures respectively. The power to the accelerating structures will be produced by either 1 MW CW or 250 kW CW klystrons/inductive output tubes (HOM IOTs). The power needed by respective feed points in the structure is max. 250 kW which will be powered by splitting the power from 1 MW klystron/klystrode into four channels by using a wave-guide system. In case of using 250 kW tubes the power to the structures will be provided directly from each tube. Two types of wave-guide transmission system have been considered, viz, WR 2300 for 350 MHz rf needs and WR 1500 for 700 MHz rf needs. The typical wave-guide system has been designed using the 1 MW CW klystron followed by wave-guide filter, dual directional coupler, high-power circulator, three 3 dB magic TEE power dividers to split the main channel into four equal channels of 250 kW each. Each individual channel has dual directional couplers, flexible wave-guide sections and high power ceramic vacuum window. The circulator and each power divider is terminated into the isolated ports by high power CW loads. Out of the four channels three channels have phase shifters. Present paper describes the technological aspects and design specifications-considerations for these stringent requirements.

  16. Power-scalable, polarization-stable, dual-colour DFB fibre laser system for CW terahertz imaging

    Eichhorn, Finn; Pedersen, Jens Engholm; Jepsen, Peter Uhd

    Imaging with electromagnetic radiation in the terahertz (THz) range has received a large amount of attention during recent years. THz imaging systems have diverse potential application areas such as security screening, medical diagnostics and non-destructive testing. We will discuss a power......-scalable, dual-colour, polarization-maintaining distributed feedback (DFB) fibre laser system with an inherent narrow linewidth from the DFB fibre laser oscillators. The laser system can be used as source in CW THz systems employing photomixing (optical heterodyning) for generation and detection...... and is an alternative to pulsed THz systems using femtosecond lasers. The laser system generates output powers up to several hundred mW, has a 25 kHz linewidth and a polarization extinction ratio of better than 20 dB. Since the output power reaches the Watt-level, the laser system is a suitable candidate for future...

  17. Operational characteristics and power scaling of a transverse flow transversely excited CW CO2 laser

    Jai Khare; R Sreedhar; C P Paul; T Reghu; A K Nath

    2003-01-01

    Transverse flow transversely excited (TFTE) CO2 lasers are easily scalable to multikilowatt level. The laser power can be scaled up by increasing the volumetric gas flow and discharge volume. It was observed in a TFTE CW CO2 laser having single row of pins as an anode and tubular cathode that the laser power was not increasing when the discharge volume and the gas volumetric flow were increased by increasing the electrode separation keeping the gas flow velocity constant. The discharge voltage too remained almost constant with the change of electrode separation at the same gas flow velocity. This necessitated revision of the scaling laws for designing this type of high power CO2 laser. Experimental results of laser performance for different electrode separations are discussed and the modifications in the scaling laws are presented.

  18. High-power CW and long-pulse lasers in the green wavelength regime for copper welding

    Pricking, Sebastian; Huber, Rudolf; Klausmann, Konrad; Kaiser, Elke; Stolzenburg, Christian; Killi, Alexander

    2016-03-01

    We report on industrial high-power lasers in the green wavelength regime. By means of a thin disk oscillator and a resonator-internal nonlinear crystal for second harmonic generation we are able to extract up to 8 kW pulse power in the few-millisecond range at a wavelength of 515 nm with a duty cycle of 10%. Careful shaping and stabilization of the polarization and spectral properties leads to a high optical-to-optical efficiency larger than 55%. The beam parameter product is designed and measured to be below 5 mm·mrad which allows the transport by a fiber with a 100 μm core diameter. The fiber and beam guidance optics are adapted to the green wavelength, enabling low transmission losses and stable operation. Application tests show that this laser is perfectly suited for copper welding due to the superior absorption of the green wavelength compared to IR, which allows us to produce weld spots with an unprecedented reproducibility in diameter and welding depth. With an optimized set of parameters we could achieve a splatter-free welding process of copper, which is crucial for welding electronic components. Furthermore, the surface condition does not influence the welding process when the green wavelength is used, which allows to skip any expensive preprocessing steps like tin-coating. With minor changes we could operate the laser in cw mode and achieved up to 1.7 kW of cw power at 515 nm with a beam parameter product of 2.5 mm·mrad. These parameters make the laser perfectly suitable for additional applications such as selective laser melting of copper.

  19. Experimental test of a supercritical helium heat exchanger dedicated to EUROTRANS 150 kW CW power coupler

    Souli, M.; Fouaidy, M.; Hammoudi, N.

    2010-05-01

    The coaxial power coupler needed for beta = 0.65 superconducting RF cavities used in the high energy section of the EUROTRANS driver should transmit 150 kW (CW operation) RF power to the proton beam. The estimated RF losses on the power coupler outer conductor in standing wave mode operation are 46 W. To remove these heat loads, a full scale copper coil heat exchanger brazed around the outer conductor was designed and tested using supercritical helium at T = 6 K as a coolant. Our main objective was to minimise the heat loads to cold extremity of SRF cavity maintained at 2 K or 4.2 K. A dedicated test facility named SUPERCRYLOOP was developed and successfully operated in order to measure the performance of the cold heat exchanger. The test cell used reproduces the realistic thermal boundary conditions of the power coupler mounted on the cavity in the cryomodule. After a short introduction, a brief discussion about the problem of power coupler cooling systems in different machines is made. After that, we describe the experimental set-up and test apparatus. Then, a heat exchanger thermal model will be developed with FEM code COSMOS/M to estimate the different heat transfer coefficients by comparison between numerical simulation results and experimental data in order to validate the design. Finally, thermo-hydraulic behavior of supercritical helium has been investigated as function of different parameters (inlet pressure, flow rate, heat loads).

  20. Physics design of a CW high-power proton Linac for accelerator-driven system

    Rajni Pande; Shweta Roy; S V L S Rao; P Singh; S Kailas

    2012-02-01

    Accelerator-driven systems (ADS) have evoked lot of interest the world over because of their capability to incinerate the MA (minor actinides) and LLFP (long-lived fission products) radiotoxic waste and their ability to utilize thorium as an alternative nuclear fuel. One of the main subsystems of ADS is a high energy (∼1 GeV) and high current (∼30 mA) CW proton Linac. The accelerator for ADS should have high efficiency and reliability and very low beam losses to allow hands-on maintenance. With these criteria, the beam dynamics simulations for a 1 GeV, 30 mA proton Linac has been done. The Linac consists of normal-conducting radio-frequency quadrupole (RFQ), drift tube linac (DTL) and coupled cavity drift tube Linac (CCDTL) structures that accelerate the beam to about 100 MeV followed by superconducting (SC) elliptical cavities, which accelerate the beam from 100 MeV to 1 GeV. The details of the design are presented in this paper.

  1. CFD assisted simulation of temperature distribution and laser power in pulsed and CW pumped static gas DPALs

    Waichman, Karol; Barmashenko, Boris D.; Rosenwaks, Salman

    2015-10-01

    An analysis of radiation, kinetic and fluid dynamic processes in diode pumped alkali lasers (DPALs) is reported. The analysis is based on a three-dimensional, time-dependent computational fluid dynamics (3D CFD) model. The CFD code which solves the gas conservation equations includes effects of natural convection and temperature diffusion of the species in the DPAL mixture. The gas flow conservation equations are coupled to the equations for DPAL kinetics and to the Beer-Lambert equations for pump and laser beams propagation. The DPAL kinetic processes in the Cs/CH4 (K/He) gas mixtures considered involve the three low energy levels, (1) n2S1/2, (2) n2P3/2 and (3) n2P1/2 (where n=4,6 for K and Cs, respectively), three excited alkali states and two alkali ionic states. Using the CFD model, the gas flow pattern and spatial distributions of the pump and laser intensities in the resonator were calculated for end-pumped CW and pulsed Cs and K DPALs. The DPAL power and medium temperature were calculated as a function of pump power and pump pulse duration. The CFD model results were compared to experimental results of Cs and K DPALs.

  2. High average power quasi-CW single-mode green and UV fiber lasers

    Avdokhin, Alexey; Gapontsev, Valentin; Kadwani, Pankaj; Vaupel, Andreas; Samartsev, Igor; Platonov, Nicholai; Yusim, Alex; Myasnikov, Daniil

    2015-02-01

    Kilowatt-level narrow-linewidth SM ytterbium fiber laser operating in high-repetition-rate QCW regime was used to obtain 700 W average power at 532 nm with single-mode beam quality and wall-plug efficiency of over 23 %. To the best of our knowledge, this is ~60 % higher power than previously reported for single-mode green lasers based on other platforms, and also is ~30 % increase comparing to the previous result obtained by our group on the base of similar fiber laser platform. We have also experimentally proved that the same type of fiber laser can be used for generating of world-record levels of power at other wavelengths of visible and UV spectral ranges by employing cascaded non-linear frequency conversion. Thus, utilizing frequency tripling in 2 LBO crystals, we achieved over 160 W average power of nearly single-mode UV light at 355 nm with THG efficiency of more than 25 %. As far as we know, this is the highest output power ever reported for UV laser with nearly diffraction limited beam quality. We also conducted some preliminary experiments to demonstrate suitability of our approach for generating longer wavelengths of the visible spectrum. By pre-shifting fundamental emission wavelength in fiber Raman converter, followed by frequency doubling in NCPM LBO, we obtained average powers of 36 W at 589 nm and 27 W at 615 nm. These proof-of-concept experiments were performed with low-power pump laser and were not fully optimized with respect to frequency conversion. Our analysis indicates that employing kW-level QCW ytterbium laser with optimized SRS and SHG converters we can achieve hundreds of Watts of average power in red and orange color with single-mode beam quality.

  3. S波段连续波Sic功率MESFET%S-Band CW SiC Power MESFETs

    陈昊; 潘宏菽; 杨霏; 霍玉柱; 商庆杰; 齐国虎; 刘志平

    2011-01-01

    The SiC MESFET devices were fabricated with the domestic SiC epitaxial materials and self-developed device process. The CW SiC devices show the advantages of high power and high gain, such as more than 10 W CW output power, larger than 9 dB power gain and no less than 35 % power-added efficiency at S-band. Compared with the previous Si microwave power devices,the volume of the SiC devices is less than 1/7 and the weight less than 20% of Si devices at the same frequency and output power. The gain of SiC devices increases more than 3 dB compared to Si devices and the efficiency is also improved. Because the input and output impedances of SiC devices are obviously higher than those of Si devices, the internally-matched network can be simplified or even removed and the higher RF power gain can be arrived. It means that the small volume and low weight of the devices can realize the higher power output.%利用国产Sic外延材料和自主开发的sic器件工艺加工技术,实现了sic微波功率器件在S波段连续波功率输出大于10 W、功率增益大于9 dB、功率附加效率不低于35%的性能样管,初步显现了Sic器件在S波段连续波大功率、高增益方面的优势.与以往的硅微波功率器件相比,在同样的频率和输出功率下,Sic微波功率器件的体积不到Si器件的1/7,重量不到Si器件的20%,其功率增益较Si器件提高了3 dB以上,器件效率也得到了相应的提高.同时由于Sic微波功率器件的输入、输出阻杭要明显高于Si微波功率器件,在一定程度上可以简化或不用内匹配网络来得到比较高的微波功率增益,这就为器件的小体积、低重量莫定了基础,也为器件的大功率输出创造了条件.

  4. Reliability aspects and facet damage in high-power emission from (AlGa)As cw laser diodes at room temperature

    Factors are described that limit the optical power output from (AlGa)As laser diodes (lambda = 8100 to 8300 A) operating cw at room temperature with uncoated facets. Rapid laser ''catastrophic'' degradation due to facet damage (in contrast to ''bulk'' phenomena previously considered) has been found to occur as a result of excessive optical flux density at the facets. The diodes studied are capable of initial cw power emission values of 25 to 100 mW from one facet depending on their dimensions. Data are presented showing long-term constant-current operation at power levels below these maximum values. Preliminary data are also presented on devices utilizing dielectric facet coatings to minimize facet damage. (U.S.)

  5. Advancement of High Power Quasi-CW Laser Diode Arrays For Space-based Laser Instruments

    Amzajerdian, Farzin; Meadows, Byron L.; Baker, nathaniel R.; Baggott, Renee S.; Singh, Upendra N.; Kavaya, Michael J.

    2004-01-01

    Space-based laser and lidar instruments play an important role in NASA s plans for meeting its objectives in both Earth Science and Space Exploration areas. Almost all the lidar instrument concepts being considered by NASA scientist utilize moderate to high power diode-pumped solid state lasers as their transmitter source. Perhaps the most critical component of any solid state laser system is its pump laser diode array which essentially dictates instrument efficiency, reliability and lifetime. For this reason, premature failures and rapid degradation of high power laser diode arrays that have been experienced by laser system designers are of major concern to NASA. This work addresses these reliability and lifetime issues by attempting to eliminate the causes of failures and developing methods for screening laser diode arrays and qualifying them for operation in space.

  6. Improving Reliability of High Power Quasi-CW Laser Diode Arrays Operating in Long Pulse Mode

    Amzajerdian, Farzin; Meadows, Byron L.; Barnes, Bruce W.; Lockard, George E.; Singh, Upendra N.; Kavaya, Michael J.; Baker, Nathaniel R.

    2006-01-01

    Operating high power laser diode arrays in long pulse regime of about 1 msec, which is required for pumping 2-micron thulium and holmium-based lasers, greatly limits their useful lifetime. This paper describes performance of laser diode arrays operating in long pulse mode and presents experimental data of the active region temperature and pulse-to-pulse thermal cycling that are the primary cause of their premature failure and rapid degradation. This paper will then offer a viable approach for determining the optimum design and operational parameters leading to the maximum attainable lifetime.

  7. Numerical calculations of a high power CW CO2 gas-dynamic laser

    Al-Hawat, Sharif; Al-Mutaib, Kheir

    2008-03-01

    Numerical solution of gas-dynamic laser equations in a gas mixture CO2:N2:H2O was carried out, using five-temperature-model (one translational and four vibrational temperatures) by a computational program written in FORTRAN. The spatial distributions of population inversion, gain and temperatures of the gas flow, in addition to the laser intensity and power extraction were studied inside the cavity, for certain initial conditions like pressure (p0=20 atm), temperature (T0= 1500 K), ratio of gases in the laser mixture (CO2:N2:H2O ≡ 10:85:5).

  8. Ion cyclotron resonance heating systems upgrade toward high power and CW operations in WEST

    Hillairet, Julien; Mollard, Patrick; Zhao, Yanping; Bernard, Jean-Michel; Song, Yuntao; Argouarch, Arnaud; Berger-By, Gilles; Charabot, Nicolas; Chen, Gen; Chen, Zhaoxi; Colas, Laurent; Delaplanche, Jean-Marc; Dumortier, Pierre; Durodié, Frédéric; Ekedahl, Annika; Fedorczak, Nicolas; Ferlay, Fabien; Goniche, Marc; Hatchressian, Jean-Claude; Helou, Walid; Jacquot, Jonathan; Joffrin, Emmanuel; Litaudon, Xavier; Lombard, Gilles; Maggiora, Riccardo; Magne, Roland; Milanesio, Daniele; Patterlini, Jean-Claude; Prou, Marc; Verger, Jean-Marc; Volpe, Robert; Vulliez, Karl; Wang, Yongsheng; Winkler, Konstantin; Yang, Qingxi; Yuan, Shuai

    2015-12-01

    The design of the WEST (Tungsten-W Environment in Steady-state Tokamak) Ion cyclotron resonance heating antennas is based on a previously tested conjugate-T Resonant Double Loops prototype equipped with internal vacuum matching capacitors. The design and construction of three new WEST ICRH antennas are being carried out in close collaboration with ASIPP, within the framework of the Associated Laboratory in the fusion field between IRFM and ASIPP. The coupling performance to the plasma and the load-tolerance have been improved, while adding Continuous Wave operation capability by introducing water cooling in the entire antenna. On the generator side, the operation class of the high power tetrodes is changed from AB to B in order to allow high power operation (up to 3 MW per antenna) under higher VSWR (up to 2:1). Reliability of the generators is also improved by increasing the cavity breakdown voltage. The control and data acquisition system is also upgraded in order to resolve and react on fast events, such as ELMs. A new optical arc detection system comes in reinforcement of the Vr/Vf and SHAD systems.

  9. Ion cyclotron resonance heating systems upgrade toward high power and CW operations in WEST

    Hillairet, Julien, E-mail: julien.hillairet@cea.fr; Mollard, Patrick; Bernard, Jean-Michel; Argouarch, Arnaud; Berger-By, Gilles; Charabot, Nicolas; Colas, Laurent; Delaplanche, Jean-Marc; Ekedahl, Annika; Fedorczak, Nicolas; Ferlay, Fabien; Goniche, Marc; Hatchressian, Jean-Claude; Helou, Walid; Jacquot, Jonathan; Joffrin, Emmanuel; Litaudon, Xavier; Lombard, Gilles; Magne, Roland; Patterlini, Jean-Claude [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France); and others

    2015-12-10

    The design of the WEST (Tungsten-W Environment in Steady-state Tokamak) Ion cyclotron resonance heating antennas is based on a previously tested conjugate-T Resonant Double Loops prototype equipped with internal vacuum matching capacitors. The design and construction of three new WEST ICRH antennas are being carried out in close collaboration with ASIPP, within the framework of the Associated Laboratory in the fusion field between IRFM and ASIPP. The coupling performance to the plasma and the load-tolerance have been improved, while adding Continuous Wave operation capability by introducing water cooling in the entire antenna. On the generator side, the operation class of the high power tetrodes is changed from AB to B in order to allow high power operation (up to 3 MW per antenna) under higher VSWR (up to 2:1). Reliability of the generators is also improved by increasing the cavity breakdown voltage. The control and data acquisition system is also upgraded in order to resolve and react on fast events, such as ELMs. A new optical arc detection system comes in reinforcement of the V{sub r}/V{sub f} and SHAD systems.

  10. A sweep plate emittance scanner for high-power CW ion beams

    Sweep plate scanners are preferred for emittance measurement due to their versatility, simplicity, and precision. At the Advanced Technology and Development Center of Northrop Grumman, we have routinely used these devices for characterization of injector beams with less than 20 W/cm2 average power density. To characterize higher power beams, like those required for production of tritium or for radioactive waste transmutation, the scanner pod and data collection algorithm must be redesigned due to the possibility of melting the scanner's protective front face or distorting the precision entrance knife edges. Among the methods we have used to mitigate these effects, one consists of drastically reducing the amount of time required for data collection. In this method, the emittance scanner pod traverses the beam in two passes, each requiring less than 0.5 second. In the first pass, the phase space limits of the beam are determined. In the second pass, data is collected primarily within the phase space region limits determined in the first pass. In this way, enough points are collected to assure that the precision of the measurement is high, even though the data collection time for each scan is less than 0.5 second. This paper will describe the layout of the scanner components, the data collection electronics and algorithm, and the data analysis. (author)

  11. Ion cyclotron resonance heating systems upgrade toward high power and CW operations in WEST

    The design of the WEST (Tungsten-W Environment in Steady-state Tokamak) Ion cyclotron resonance heating antennas is based on a previously tested conjugate-T Resonant Double Loops prototype equipped with internal vacuum matching capacitors. The design and construction of three new WEST ICRH antennas are being carried out in close collaboration with ASIPP, within the framework of the Associated Laboratory in the fusion field between IRFM and ASIPP. The coupling performance to the plasma and the load-tolerance have been improved, while adding Continuous Wave operation capability by introducing water cooling in the entire antenna. On the generator side, the operation class of the high power tetrodes is changed from AB to B in order to allow high power operation (up to 3 MW per antenna) under higher VSWR (up to 2:1). Reliability of the generators is also improved by increasing the cavity breakdown voltage. The control and data acquisition system is also upgraded in order to resolve and react on fast events, such as ELMs. A new optical arc detection system comes in reinforcement of the Vr/Vf and SHAD systems

  12. Ion cyclotron resonance heating systems upgrade toward high power and CW operations in WEST

    Hillairet, Julien; Zhao, Yanping; Bernard, Jean-Michel; Song, Yuntao; Argouarch, Arnaud; Berger-By, Gilles; Charabot, Nicolas; Chen, Gen; Chen, Zhaoxi; Colas, Laurent; Delaplanche, Jean-Marc; Dumortier, Pierre; Durodié, Frédéric; Ekedahl, Annika; Fedorczak, Nicolas; Ferlay, Fabien; Goniche, Marc; Hatchressian, Jean-Claude; Helou, Walid; Jacquot, Jonathan; Joffrin, Emmanuel; Litaudon, Xavier; Lombard, Gilles; Maggiora, Riccardo; Magne, Roland; Milanesio, Daniele; Patterlini, Jean-Claude; Prou, Marc; Verger, Jean-Marc; Volpe, Robert; Vulliez, Karl; Wang, Yongsheng; Winkler, Konstantin; Yang, Qingxi; Yuan, Shuai

    2016-01-01

    The design of the WEST (Tungsten-W Environment in Steady-state Tokamak) Ion cyclotron resonance heating antennas is based on a previously tested conjugate-T Resonant Double Loops prototype equipped with internal vacuum matching capacitors. The design and construction of three new WEST ICRH antennas are being carried out in close collaboration with ASIPP, within the framework of the Associated Laboratory in the fusion field between IRFM and ASIPP. The coupling performance to the plasma and the load-tolerance have been improved, while adding Continuous Wave operation capability by introducing water cooling in the entire antenna. On the generator side, the operation class of the high power tetrodes is changed from AB to B in order to allow high power operation (up to 3 MW per antenna) under higher VSWR (up to 2:1). Reliability of the generators is also improved by increasing the cavity breakdown voltage. The control and data acquisition system is also upgraded in order to resolve and react on fast events, such a...

  13. High average power CW FELs [Free Electron Laser] for application to plasma heating: Designs and experiments

    A short period wiggler (period ∼ 1 cm), sheet beam FEL has been proposed as a low-cost source of high average power (1 MW) millimeter-wave radiation for plasma heating and space-based radar applications. Recent calculation and experiments have confirmed the feasibility of this concept in such critical areas as rf wall heating, intercepted beam (''body'') current, and high voltage (0.5 - 1 MV) sheet beam generation and propagation. Results of preliminary low-gain sheet beam FEL oscillator experiments using a field emission diode and pulse line accelerator have verified that lasing occurs at the predicted FEL frequency. Measured start oscillation currents also appear consistent with theoretical estimates. Finally, we consider the possibilities of using a short-period, superconducting planar wiggler for improved beam confinement, as well as access to the high gain, strong pump Compton regime with its potential for highly efficient FEL operation

  14. A high power CW or long pulse klystron: 500 kW at 3.7 GHz

    The design, technology, and preliminary test results for a new klystron for LHRH is described. The tube will deliver 500 kW in long pulse (min.) or CW operation at 3.7 GHz, with 45% efficiency into a high, fluctuating SWR

  15. High-power CW and passively Q-switched laser operation of Yb:GdCa4O(BO3)3 crystal

    Chen, Xiaowen; Wang, Lisha; Liu, Junhai; Guo, Yunfeng; Han, Wenjuan; Xu, Honghao; Yu, Haohai; Zhang, Huaijin

    2016-05-01

    We demonstrate efficient high-power CW and passively Q-switched operations of Yb:GdCa4O(BO3)3 lasers. An output power of 18.2 W is generated at 1031.5 nm in CW mode, with optical-to-optical and slope efficiencies being respectively 55% and 70%, with respect to incident pump power. In passively Q-switched operation with a Cr4+:YAG crystal as saturable absorber, a maximum average output power of 15.6 W is produced at a pulse repetition rate of 91 kHz, with an optical-to-optical efficiency of 44%. Low-repetition-rate Q-switched action is also realized, generating an average output power of 4.2 W at 5.7 kHz, the resulting pulse energy and duration are 737 μJ and 3.6 ns, leading to a peak power amounting to 205 kW.

  16. Observation of snowfall with a low-power FM-CW K-band radar (Micro Rain Radar)

    Kneifel, Stefan; Maahn, Maximilian; Peters, Gerhard; Simmer, Clemens

    2011-06-01

    Quantifying snowfall intensity especially under arctic conditions is a challenge because wind and snow drift deteriorate estimates obtained from both ground-based gauges and disdrometers. Ground-based remote sensing with active instruments might be a solution because they can measure well above drifting snow and do not suffer from flow distortions by the instrument. Clear disadvantages are, however, the dependency of e.g. radar returns on snow habit which might lead to similar large uncertainties. Moreover, high sensitivity radars are still far too costly to operate in a network and under harsh conditions. In this paper we compare returns from a low-cost, low-power vertically pointing FM-CW radar (Micro Rain Radar, MRR) operating at 24.1 GHz with returns from a 35.5 GHz cloud radar (MIRA36) for dry snowfall during a 6-month observation period at an Alpine station (Environmental Research Station Schneefernerhaus, UFS) at 2,650 m height above sea level. The goal was to quantify the potential and limitations of the MRR in relation to what is achievable by a cloud radar. The operational MRR procedures to derive standard radar variables like effective reflectivity factor ( Z e) or the mean Doppler velocity ( W) had to be modified for snowfall since the MRR was originally designed for rain observations. Since the radar returns from snowfall are weaker than from comparable rainfall, the behavior of the MRR close to its detection threshold has been analyzed and a method is proposed to quantify the noise level of the MRR based on clear sky observations. By converting the resulting MRR- Z e into 35.5 GHz equivalent Z e values, a remaining difference below 1 dBz with slightly higher values close to the noise threshold could be obtained. Due to the much higher sensitivity of MIRA36, the transition of the MRR from the true signal to noise can be observed, which agrees well with the independent clear sky noise estimate. The mean Doppler velocity differences between both radars

  17. CW laser light condensation.

    Zhurahov, Michael; Bekker, Alexander; Levit, Boris; Weill, Rafi; Fischer, Baruch

    2016-03-21

    We present a first experimental demonstration of classical CW laser light condensation (LC) in the frequency (mode) domain that verifies its prediction (Fischer and Weill, Opt. Express20, 26704 (2012)). LC is based on weighting the modes in a noisy environment in a loss-gain measure compared to an energy (frequency) scale in Bose-Einstein condensation (BEC). It is characterized by a sharp transition from multi- to single-mode oscillation, occurring when the spectral-filtering (loss-trap) has near the lowest-loss mode ("ground-state") a power-law dependence with an exponent smaller than 1. An important meaning of the many-mode LC system stems from its relation to lasing and photon-BEC. PMID:27136845

  18. Design and Construction of a 500 kW CW, 400 MHz Klystron to be used as RF Power Source for LHC/RF Component Tests

    Frischholz, H.; Fowkes, W. R.; Pearson, C.

    1997-05-01

    A 500 kW CW klystron operating at 400 MHz was jointly developed and constructed by CERN and SLAC for use as a high power source at CERN for testing LHC/RF components such as circulators, RF absorbers and superconducting cavities with their input couplers. The design is a modification of the 353 MHz SLAC PEP-I klystron which resulted in lower engineering costs as well as reduced development and construction time. More than 80% of the original PEP-I tube parts could be incorporated in the LHC test klystron. The physical length between cathode plane and upper pole plate was kept unchanged so that a PEP-I tube focusing frame, available at CERN, could be re-used. With the aid of the klystron simulation codes JPNDISK and CONDOR, the design of the LHC tube was accomplished, which resulted in a tube with noticeably higher efficiency than its predecessor, the PEP-I klystron. The integrated cavities were redesigned by using SUPERFISH and the output coupling circuit, which also required redesigning, was done with the aid of MAFIA. Details of the tube development and test results are presented. Finally the set-up of the LHC/RF test stand and the features of its auxiliary high-power RF equipment, such as circulator and absorber, are described.

  19. All-solid-state cw frequency-doubling Nd:YLiF4/LBO blue laser with 4.33 W output power at 454 nm under in-band diode pumping at 880 nm.

    Lü, Yanfei; Zhang, Xihe; Cheng, Weibo; Xia, Jing

    2010-07-20

    We generated efficient blue laser output at 454 nm by intracavity frequency doubling of a continuous-wave (cw) diode-pumped Nd:YLiF(4) (Nd:YLF) laser at 908 nm based on the (4)F(3/2)-(4)I(9/2) transition. With 32.8 W of incident pump power at 880 nm and the frequency-doubling crystal LiB(3)O(5), a level as high as 4.33 W of cw output power at 454 nm is achieved, corresponding to an optical conversion efficiency of 13.2% with respect to the incident pump power. To the best of our knowledge, this is the first blue laser at 454 nm generated by intracavity frequency doubling of a diode-pumped Nd:YLF. PMID:20648194

  20. Design and Construction of a 500 KW CW, 400 MHZ Klystron To Be Used As RF Power Source For LHC/RF Component Tests

    A 500 kW cw klystron operating at 400 MHz was developed and constructed jointly by CERN and SLAC for use as a high-power source at CERN for testing LHC/RF components such as circulators, RF absorbers and superconducting cavities with their input couplers. The design is a modification of the 353 MHz SLAC PEP-I klystron. More than 80% of the original PEP-I tube parts could thus be incorporated in the LHC test klystron which resulted in lower engineering costs as well as reduced development and construction time. The physical length between cathode plane and upper pole plate was kept unchanged so that a PEP-I tube focusing solenoid, available at CERN, could be re-used. With the aid of the klystron simulation codes JPNDISK and CONDOR, the design of the LHC tube was accomplished, which resulted in a tube with noticeably higher efficiency than its predecessor, the PEP-I klystron. The integrated cavities were redesigned using SUPERFISH and the output coupling circuit, which also required redesigning, was done with the aid of MAFIA. Details of the tube development and test results are presented

  1. Production of high-power CW UV by resonant frequency quadrupling of a Nd:YLF laser

    The authors have constructed a single ring to resonantly double an 18 watt Nd:YLF mode-locked laser and re-double the stored green to produce over 4 watts of power in the ultra-violet (UV). This laser is used to produce a beam of 470 MeV gamma-rays by Compton backscattering the laser beam from 2.8 GeV electrons stored in a synchrotron. Achieving high luminosity of the colliding beams requires very good mode quality and beam stability at the intersection point 22 meters from the laser. The ring consists of six mirrors, with two 25 cm radius of curvature mirrors enclosing each nonlinear crystal. The drive laser is a lamp-pumped Nd:YLF with a 50 ps bunch length at 76 MHz. A pointing stabilizer servo has been constructed as part of the infrared (IR) mode matching telescope. The IR to green conversion is accomplished in a 15 mm long non-critically phased matched LBO crystal located at a 40 micron waist, with an IR conversion efficiency of 70%. A stable, nearly diffraction limited UV beam of up to 4.2 watts is generated in a BBO crystal in the green storage ring. The output power is relatively independent of the efficiency of the LBO and BBO crystals. This fact makes it possible to reduce the amount of non-TEM00 modes created by walk-off of the UV by using relatively thin BBO crystals. At present, however, the lower bound on the BBO thickness is limited by the loss of conversion efficiency at high power

  2. Generation of 14  W at 589  nm by frequency doubling of high-power CW linearly polarized Raman fiber laser radiation in MgO:sPPLT crystal.

    Surin, A A; Borisenko, T E; Larin, S V

    2016-06-01

    We introduce an efficient, single-mode, linearly polarized continuous wave (CW) Raman fiber laser (RFL), operating at 1178 nm, with 65 W maximum output power and a narrow linewidth of 0.1 nm. Single-pass second-harmonic generation was demonstrated using a 20 mm long MgO-doped stoichiometric periodically polled lithium tantalate (MgO:sPPLT) crystal pumped by RFL radiation. Output power of 14 W at 589 nm with 22% conversion efficiency was achieved. The possibility of further power scaling is considered, as no crystal degradation was observed at these power levels. PMID:27244435

  3. Spin-label CW microwave power saturation and rapid passage with triangular non-adiabatic rapid sweep (NARS) and adiabatic rapid passage (ARP) EPR spectroscopy

    Kittell, Aaron W.; Hyde, James S.

    2015-06-01

    Non-adiabatic rapid passage (NARS) electron paramagnetic resonance (EPR) spectroscopy was introduced by Kittell et al. (2011) as a general purpose technique to collect the pure absorption response. The technique has been used to improve sensitivity relative to sinusoidal magnetic field modulation, increase the range of inter-spin distances that can be measured under near physiological conditions (Kittell et al., 2012), and enhance spectral resolution in copper (II) spectra (Hyde et al., 2013). In the present work, the method is extended to CW microwave power saturation of spin-labeled T4 Lysozyme (T4L). As in the cited papers, rapid triangular sweep of the polarizing magnetic field was superimposed on slow sweep across the spectrum. Adiabatic rapid passage (ARP) effects were encountered in samples undergoing very slow rotational diffusion as the triangular magnetic field sweep rate was increased. The paper reports results of variation of experimental parameters at the interface of adiabatic and non-adiabatic rapid sweep conditions. Comparison of the forward (up) and reverse (down) triangular sweeps is shown to be a good indicator of the presence of rapid passage effects. Spectral turning points can be distinguished from spectral regions between turning points in two ways: differential microwave power saturation and differential passage effects. Oxygen accessibility data are shown under NARS conditions that appear similar to conventional field modulation data. However, the sensitivity is much higher, permitting, in principle, experiments at substantially lower protein concentrations. Spectral displays were obtained that appear sensitive to rotational diffusion in the range of rotational correlation times of 10-3 to 10-7 s in a manner that is analogous to saturation transfer spectroscopy.

  4. FM-cw radar for imaging applications

    Bjornholt, John E.; Wilson, Terry B.

    1998-10-01

    FM-CW radars operating in the millimeter wave or upper microwave bands can provide low cost, low power solutions for many applications requiring the resolution of targets separated by one meter or less in range. Range resolution of this quality is obtained by sweeping the radar output frequency over several hundred megahertz of bandwidth using modern techniques to achieve extremely good linearity. Because of the short wavelengths at millimeter bands, relatively good angular resolution is achievable with moderately sized antennas. Applications for FM-CW radar sensors include automotive collision warning systems, traffic monitoring, height profiling, terrain profiling, autonomous vehicle navigation, surveillance and site security systems where high resolution is required.

  5. Generation of high power cw laser light at 257 nm for laser cooling of intense 24Mg+ beams at the ESR

    We report on the generation of 750 mW cw laser radiation at a wavelength of 257 nm obtained by frequency doubling the green Ar+ line in a Brewster-cut BBO crystal placed in the spherical focus of an external ring resonator. The system is optimized for laser cooling studies of intense 83.7 MeV 21Mg+ ion beams at the ESR dedicated to the investigation of space charge-dominated beams

  6. Performance of wire scanner beam profile monitors to determine the emittance and position of high power CW electron beams of the NBS-Los Alamos racetrack microtron

    The NBS-LANL Race Track Microtron (RTM) injector produces a sub-millimeter diameter, 600 μA, 5 MeV CW electron beam. In order to steer and focus this electron beam and to measure its emittance and energy spread, a system of wire scanner beam profile monitors has been developed. Three wire scanners are mounted in a straight line with approximately one meter spacing for emittance measurements. The fourth wire scanner is positioned after a 450 bending magnet for energy spread measurements

  7. FM-CW radar performance in a lossy layered medium

    Deng, Ruili; Liu, Ce

    1999-08-01

    FM-CW radar is capable of detecting subsurface anomalies by using linear sweep frequency transmission of a periodically repetitive continuous FM signal. Due to the continuous-wave nature, the peak power of the FM-CW radar is usually in the range of hundreds of milliwatts. In cases where high resolution is necessary, the FM-CW radar is preferred because of the simple hardware structure and the availability of low-power components. The distance from the antenna to an anomaly can be determined by FM-CW radar in lossless media. In this paper, we present both analytical and numerical methods for modelling FM-CW radar performance in lossless and lossy layered formations for 1D and 2D cases. The FM-CW operating frequency is set in the range of 1-2 GHz, and the sweep periods are 10 ms and 2 ms, respectively. An inversion formulation is discussed to invert the distance and dielectric constant simultaneously from the spectrum of the received signal by using FFT and the `range equation'. The spatial resolution is about one-third of the center wavelength and the depth of penetration is about 4 m in a medium having a conductivity less than 1 mS/m. The FM-CW radar technique cannot be used in a lossy medium having conductivity more than 30 mS/m. The spectrum and images of multilayer formations is also studied.

  8. A 100 MV cryomodule for CW operation

    Charles Reece

    2005-07-10

    A cryomodule designed for high-gradient CW operation has been built at Jefferson Lab. The Renascence cryomodule is the final prototype of a design for use in the 12 GeV CEBAF upgrade. The module uses eight 7-cell 1497 MHz cavities to be individually powered by 13 kW klystrons. Specifications call for providing >109 MV CW with < 250 W of dynamic heat at 2.07 K. The module incorporates a new generation of tuners and higher power input waveguides. A mixture of the new HG and LL cavity shapes are used. A new high thermal conductivity RF feedthrough has been developed and used on the 32 HOM coupler probes of Renascence. The cryomodule assembly is complete. Testing is to begin late June. Design features and initial test data will be presented.

  9. 50W CW output power and 12mJ pulses from a quasi-2-level Yb:YAG ceramic rod laser end-pumped at the 969nm zero-phonon line

    Fries, Christian; Weitz, Marco; Theobald, Christian; v. Löwis of Menar, Patric; Bartschke, Jürgen; L'huillier, Johannes A.

    2015-02-01

    With the advent of high power and narrow bandwidth 969 nm pump diodes, direct pumping into the upper laser level of Yb:YAG and hence quasi-2-level lasers became possible. Pumping directly into the emitting level leads to higher quantum efficiency and reduction of non-radiative decay. Consequently, thermal load, thermal lensing and risk of fracture are reduced significantly. Moreover pump saturation and thermal population of uninvolved energy-levels in ground and excited states are benefical for a homogenous distribution of the pump beam as well as the reduction of reabsorption loss compared to 3-level systems, which allows for high-power DPSS lasers. Beside continuous-wave (cw) operation, nanosecond pulses with a repetition rate between 1 and 5 kHz are an attractive alternative to flashlamp-pumped systems (10-100 Hz) in various measurement applications that require higher data acquisition rates because of new faster detectors. Based on measurements of the absorption and a detailed numerical model for pump beam distribution, including beam propagation and saturation factors, power-scaling of a ceramic rod Yb:YAG oscillator was possible. Finally a cw output power of 50 W with 33 % pump efficiency at 1030 nm has been demonstrated (M2 < 1.2). Nanosecond pulses have been produced by cavity-dumping of this system. The cavity-dumped setup allowed for 3-10 ns pulses with a pulse energy of 12.5 mJ at 1 kHz (M2 < 1.1). In order to achieve these results a systematic experimental and numerical investigation on gain dynamics and the identification of different stable operating regimes has been carried out.

  10. Dissimilar autogenous full penetration welding of superalloy K418 and 42CrMo steel by a high power CW Nd:YAG laser

    Experiments of autogenous laser full penetration welding between dissimilar cast Ni-based superalloy K418 and alloy steel 42CrMo flat plates with 3.5 mm thickness were conducted using a 3 kW continuous wave (CW) Nd:YAG laser. The influences of laser welding velocity, flow rate of side-blow shielding gas, defocusing distance were investigated. Microstructure of the welded seam was characterized by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). Mechanical properties of the welded seam were evaluated by microhardness and tensile strength testing. Results show that high quality full penetration laser-welded joint can be obtained by optimizing the welding velocity, flow rate of shielding gas and defocusing distance. The laser-welded seam have non-equilibrium solidified microstructures consisting of γ-FeCr0.29Ni0.16C0.06 austenite solid solution dendrites as the dominant and very small amount of super-fine dispersed Ni3Al γ' phase and Laves particles as well as MC needle-like carbides distributed in the interdendritic regions. Although the microhardness of the laser-welded seam was lower than that of the base metal, the strength of the joint was equal to that of the base metal and the fracture mechanism showed fine ductility

  11. Zero-dispersion wavelength independent quasi-CW pumped supercontinuum generation

    Larsen, Casper; Sørensen, Simon Toft; Noordegraaf, Danny;

    2013-01-01

    Continuous wave (CW) pumped supercontinuum generation depends strongly on the zero-dispersion wavelength (ZDW) of the fiber due to the low peak power. Here we study several photonic crystal fibers by use of a gain-switched CW pump laser and investigate for what power level the supercontinuum...

  12. Diode-pumped CW molecular lasers

    Wellegehausen, B.; Luhs, W.

    2016-05-01

    First continuous laser oscillation on many lines in the range of 533-635 nm on different transitions of Na2 and Te2 molecules has been obtained, optically pumped with common cw blue emitting InGaN diode lasers operating around 445 and 460 nm. Spectral narrowing of the diode laser is achieved with a beamsplitter and grating setup, allowing use of more than 50 % of the diode power. Operation conditions and properties of the laser systems are presented, and perspectives for the realization of compact low cost molecular lasers are discussed.

  13. CW RFQ fabrication and engineering

    The design and fabrication of a four-vane RFQ to deliver a 100 mA CW proton beam at 6.7 MeV is described. This linac is an Oxygen-Free Electrolytic (OFE) copper structure 8 m in length and was fabricated using hydrogen furnace brazing as the joining technology

  14. Design considerations in achieving 1 MW CW operation with a whispering-gallery-mode gyrotron

    Varian is developing high-power, CW gyrotrons at frequencies in the range 100 GHz to 150 GHz, for use in electron cyclotron heating applications. Early test vehicles have utilized a TE15,2,1 interaction cavity, have achieved short-pulse power levels of 820 kW and average power levels of 80 kW at 140 GHz. Present tests are aimed at reaching 400 kW under CW operating conditions and up to 1 MW for short pulse durations. Work is also underway on modifications to the present design that will enable power levels of up to 1 MW CW to be achieved. 7 refs., 2 figs

  15. 600-W lamp pumped CW Nd:YAG laser

    Qiang Li(李强); Zhimin Wang(王志敏); Zhiyong Wang(王智勇); Zhensheng Yu(于振声); Hong Lei(雷訇); Jiang Guo(郭江); Gang Li(李港); Tiechuan Zuo(左铁钏)

    2003-01-01

    A lamp pumped CW Nd:YAG laser is presented in this paper for the requirement of industrial application.The main factors, which affect output power and beam quality of high power solid-state laser module, are theoretically analyzed. Total electro-optics efficiency of lamp pumped Nd:YAG crystal as high as 4.0% is obtained, and output power is higher than 647 W with beam parameter product 22 mm.mrad.

  16. First experiments with gasdynamic ion source in CW mode

    Skalyga, V., E-mail: skalyga@ipfran.ru; Vodopyanov, A. [Institute of Applied Physics, Russian Academy of Sciences (IAP RAS), 46 Ul‘yanova St., Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina St., Nizhny Novgorod 603950 (Russian Federation); Izotov, I.; Golubev, S. [Institute of Applied Physics, Russian Academy of Sciences (IAP RAS), 46 Ul‘yanova St., Nizhny Novgorod 603950 (Russian Federation); Tarvainen, O. [Department of Physics, University of Jyvaskyla, P.O. Box 35 (YFL), 40500 Jyvaskyla (Finland)

    2016-02-15

    A new type of ECR ion source—a gasdynamic ECR ion source—has been recently developed at the Institute of Applied Physics. The main advantages of such device are extremely high ion beam current with a current density up to 600–700 emA/cm{sup 2} in combination with low emittance, i.e., normalized RMS emittance below 0.1 π mm mrad. Previous investigations were carried out in pulsed operation with 37.5 or 75 GHz gyrotron radiation with power up to 100 kW at SMIS 37 experimental facility. The present work demonstrates the first experience of operating the gasdynamic ECR ion source in CW mode. A test bench of SMIS 24 facility has been developed at IAP RAS. 24 GHz radiation of CW gyrotron was used for plasma heating in a magnetic trap with simple mirror configuration. Initial studies of plasma parameters were performed. Ion beams with pulsed and CW high voltage were successfully extracted from the CW discharge. Obtained experimental results demonstrate that all advantages of the gasdynamic source can be realized also in CW operation.

  17. First experiments with gasdynamic ion source in CW mode

    Skalyga, V.; Izotov, I.; Golubev, S.; Vodopyanov, A.; Tarvainen, O.

    2016-02-01

    A new type of ECR ion source—a gasdynamic ECR ion source—has been recently developed at the Institute of Applied Physics. The main advantages of such device are extremely high ion beam current with a current density up to 600-700 emA/cm2 in combination with low emittance, i.e., normalized RMS emittance below 0.1 π mm mrad. Previous investigations were carried out in pulsed operation with 37.5 or 75 GHz gyrotron radiation with power up to 100 kW at SMIS 37 experimental facility. The present work demonstrates the first experience of operating the gasdynamic ECR ion source in CW mode. A test bench of SMIS 24 facility has been developed at IAP RAS. 24 GHz radiation of CW gyrotron was used for plasma heating in a magnetic trap with simple mirror configuration. Initial studies of plasma parameters were performed. Ion beams with pulsed and CW high voltage were successfully extracted from the CW discharge. Obtained experimental results demonstrate that all advantages of the gasdynamic source can be realized also in CW operation.

  18. Synchronous pumping of an optical parametric oscillator using an amplified quasi-cw pump envelope

    Butterworth, S.D.; Clarkson, W. A.; Moore, N.; Friel, G.J.; Hanna, D.C.

    1996-01-01

    Pulse-slicing from a cw laser output followed by high gain amplification can produce quasi-cw pulses at power levels well in excess of those available from large frame cw lasers. Mode-locked pulse trains with an envelope of 10µs duration and at 2kHz repetition rate are amplified by a factor of 20 to give 5 Watts of envelope average power. These power levels allow efficient single-pass frequency doubling and subsequent pumping of a lithium triborate optical parametric oscillator

  19. CW operation of an intracavity pumped molecular submillimeter-wave laser

    Koepf, G. A.

    1977-01-01

    The 373-micron line of CH3CN was operated in a CW mode in an arrangement where the submillimeter (SMM)-wave laser is placed inside the resonator of the CO2 pump laser. 1 mW of CW output power was obtained; this is five times the power of a comparable SMM-wave laser in the common extracavity arrangement. In a pulsed mode, a peak power of 46 mW was measured.

  20. The formation of trinitite-like surrogate nuclear explosion debris (SNED) and extreme thermal fractionation of SRM-612 glass induced by high power CW CO2 laser irradiation

    We describe a new approach to the bench top production of surrogate nuclear explosion debris by employing high power continuous wave CO2 laser irradiation. High surface temperatures >2,500 K can be rapidly attained, allowing virtually any combination of materials to be fused into a glassy matrix that can display high levels of elemental fractionation. Examples of the laser fused glasses will be presented and compared to trinitite nuclear explosion glass along with the elemental fractionation effects that were induced in the NIST glass standard SRM-612 by this method. (author)

  1. Efficient room temperature cw Yb:glass laser pumped by a 946nm Nd:YAG laser

    R. Koch; Clarkson, W.A.; Hanna, D.C.; Jiang, S.; Myers, M J; Rhonehouse, D.; Hamlin, S.J.; Griebner, U.; Schönnagel, H.

    1997-01-01

    By pumping with a cw diode-pumped Nd:YAG laser operating at 946nm laser operation of a new Yb-doped phosphate glass with 440mW cw output power and a slope efficiency of 48% with respect to the absorbed pump power was achieved at room temperature

  2. 100 GHz, 1 MW, CW gyrotron study program. Final report

    The results of a study program to investigate the feasibility of various approaches in designing a 100 GHz, 1 MW CW gyrotron are presented. A summary is given of the possible configurations for a high average power, high frequency gyrotron, including an historical survey of experimental results which are relevant to the various approaches. A set of basic scaling considerations which enable qualitative comparisons between particular gyrotron interaction circuits is presented. These calculations are important in understanding the role of various electron beam and circuit parameters in achieving a viable gyrotron design. Following these scaling exercises, a series of design calculations is presented for a possible approach in achieving 100 GHz, 1 MW CW. These calculations include analyses of the electron gun and interaction circuit parts of the gyrotron, and a general analysis of other aspects of a high average power, high frequency gyrotron. Scalability of important aspects of the design to other frequencies is also discussed, as well as key technology issues

  3. Resonance control for a cw [continuous wave] accelerator

    A resonance-control technique is described that has been successfully applied to several cw accelerating structures built by the Los Alamos National Laboratory for the National Bureau of Standards and for the University of Illinois. The technique involves sensing the rf fields in an accelerating structure as well as the rf power feeding into the cavity and, then, using the measurement to control the resonant frequency of the structure by altering the temperature of the structure. The temperature of the structure is altered by adjusting the temperature of the circulating cooling water. The technique has been applied to continuous wave (cw) side-coupled cavities only but should have applications with most high-average-power accelerator structures. Some additional effort would be required for pulsed systems

  4. Fiber Optic Coupling of CW Linear Laser Diode Array

    WANG Xiaowei; XIAO Jianwei; MA Xiaoyu; WANG Zhongming; FANG Gaozhan

    2002-01-01

    Based on a set of microoptics the output radiation from a continuous wave (CW) linear laser diode array is coupled into a multi-mode optical fiber of 400 μm diameter.The CW linear laser diode array is a 1 cm laser diode bar with 19 stripes with 100 μm aperture spaced on 500 μm centers.The coupling system contains packaged laser diode bar,fast axis collimator,slow axis collimation array,beam transformation system and focusing system.The high brightness,high power density and single fiber output of a laser diode bar is achieved.The coupling efficiency is 65% and the power density is up to 1.03×104 W/cm2.

  5. Two-step resonance ionization spectroscopy of Na atomic beam using cw and pulsed lasers

    Two-step photoionization of sodium atomic beam has been carried out using a cw and a pulsed dye lasers. Sodium ions have been detected by a time of flight method in order to reduce background noise. With a proper power of the pulsed dye laser the sodium atomic beam has been irradiated by a resonant cw dye laser. The density of the sodium atomic beam is estimated to be 103 cm-3 at the ionization area. (author)

  6. Design of 250-MW CW RF system for APT

    The design for the RF systems for the APT (Accelerator Production of Tritium) proton linac will be presented. The linac produces a continuous beam power of 130 MW at 1300 MeV with the installed capability to produce up to a 170 MW beam at 1700 MeV. The linac is comprised of a 350 MHz RFQ to 7 MeV followed in sequence by a 700 MHz coupled-cavity drift tube linac, coupled-cavity linac, and superconducting (SC) linac to 1700 MeV. At the 1700 MeV, 100 mA level the linac requires 213 MW of continuous-wave (CW) RF power. This power will be supplied by klystrons with a nominal output power of 1.0 MW. 237 kystrons are required with all but three of these klystrons operating at 700 MHz. The klystron count includes redundancy provisions that will be described which allow the RF systems to meet an operational availability in excess of 95 percent. The approach to achieve this redundancy will be presented for both the normal conducting (NC) and SC accelerators. Because of the large amount of CW RF power required for the APT linac, efficiency is very important to minimize operating cost. Operation and the RF system design, including in-progress advanced technology developments which improve efficiency, will be discussed. RF system performance will also be predicted. Because of the simultaneous pressures to increase RF system reliability, reduce tunnel envelope, and minimize RF system cost, the design of the RF vacuum windows has become an important issue. The power from a klystron will be divided into four equal parts to minimize the stress on the RF vacuum windows. Even with this reduction, the RF power level at the window is at the upper boundary of the power levels employed at other CW accelerator facilities. The design of a 350 MHz, coaxial vacuum window will be presented as well as test results and high power conditioning profiles. The transmission of 950 kW, CW, power through this window has been demonstrated with only minimal high power conditioning

  7. LOT-G3: Plasma Lamp, Ozonator and CW transmitter

    Gobato, Ricardo; Gobato, Alekssander

    2015-01-01

    The LOT-G3 is designed to be a versatile equipment that perform several simple experiments for use in helping the physics classes for high school. Easy construction, low cost, using easily accessible materials. Its construction involves simple practices and knowledge of electromagnetism. It has the function of a plasma globe to demonstrate the ionization of a low pressure gas, as well as the formation of magnetic field. Can be used as sanitizer closed environments such as automotive vehicles in ozonator function, demonstrating the ionization of oxygen in the atmosphere, producing ozone, essential to life on earth. And as a sparks transmitter, low power, low frequency modulated continuous wave in (CW), for signals in Morse code. Therefore the equipment here called LOT-G3, has three functions: a plasma lamp, ozonator and CW transmitter.

  8. 93.7 W 1112 nm diode-side-pumped CW Nd:YAG laser

    Li, C. Y.; Wang, Z. C.; Xu, Y. T.; Yang, F.; Wang, B. S.; Gao, H. W.; Bo, Y.; Peng, Q. J.; Cui, D. F.; Xu, Z. Y.

    2010-07-01

    We demonstrate a high power continuous wave (CW) infrared laser operated at 1112 nm from a diode side-pumped Nd:YAG crystal with a plano-plano symmetrical resonator. By inserting an etalon, an output power of as high as 93.7 W at 1112 nm was obtained at the pump power of 570 W with conversion efficiency of 16.4%. The beam quality factor of M2 was measured to be about 17. The wavelength tunable performance of the etalon was also analyzed. To the best of our knowledge, it is the highest output power at 1112 nm CW laser based on Nd:YAG crystal.

  9. 219.3 W CW diode-side-pumped 1123 nm Nd:YAG laser

    Li, C. Y.; Bo, Y.; Xu, Y. T.; Yang, F.; Wang, Z. C.; Wang, B. S.; Xu, J. L.; Gao, H. W.; Peng, Q. J.; Cui, D. F.; Xu, Z. Y.

    2010-07-01

    We demonstrate a high power continuous wave (CW) diode-side-pumped Nd:YAG laser operating at 1123 nm with a plano-plano configuration. By means of precise coating, a single 1123 nm wavelength is achieved. Under the pump power of 1080 W, an output power of 219.3 W is obtained, which corresponds to an optical-optical conversion efficiency of 20.3%. To the best of our knowledge, this is the highest output power for CW 1123 nm laser based on Nd:YAG crystal.

  10. Velocity-aided range acquisition and tracking in dual-mode CW/FM-CW radar

    Saunders, W. K.

    1989-08-01

    A technique is described that permits velocity information gained in the CW or interrupted-CW mode of a multimode radar to be fully exploited. In particular, the information is used to produce filters that move to follow changes in the range beat during an FM-CW or interrupted FM-CW mode. These filters are matched to velocity and this results in a considerable increase in the signal to noise ratio. In some applications the technique permits valuable adaptation of the FM sweep time and other parameters.

  11. Argonne CW Linac (ACWL) - legacy from SDI and opportunities for the future

    The former Strategic Defense Initiative Organization (SDIO) invested significant resources over a 6-year period to develop and build an accelerator to demonstrate the launching of a cw beam with characteristics suitable for a space-based Neutral Particle Beam (NPB) system. This accelerator, the CWDD (Continuous Wave Deuterium Demonstrator) accelerator, was designed to accelerate 80 mA cw of D- to 7.5 MeV. A considerable amount of hardware was constructed and installed in the Argonne-based facility, and major performance milestones were achieved before program funding from the Department of Defense ended in October 1993. Existing assets have been turned over to Argonne. Assets include a fully functional 200 kV cw D- injector, a cw RFQ that has been tuned, leak checked and aligned, beam lines and a high-power beam stop, all installed in a shielded vault with appropriate safety and interlock systems. In addition, there are two high power (1 MW) cw rf amplifiers and all the ancillary power, cooling and control systems required for a high-power accelerator system. The SDI mission required that the CWDD accelerator structures operate at cryogenic temperatures (26K), a requirement that placed severe limitations on operating period (CWDD would have provided 20 seconds of cw beam every 90 minutes). However, the accelerator structures were designed for full-power rf operation with water cooling and ACWL (Argonne Continuous Wave Linac), the new name for CWDD in its water-cooled, positive-ion configuration, will be able to operate continuously. Project status and achievements will be reviewed. Preliminary design of a proton conversion for the RFQ, and other proposals for turning ACWL into a testbed for cw-linac engineering, will be discussed

  12. A portable CW/FM-CW Doppler radar for local investigation of severe storms

    Unruh, Wesley P.; Wolf, Michael A.; Bluestein, Howard B.

    During the 1987 spring storm season we used a portable 1-W X-band CW Doppler radar to probe a tornado, a funnel cloud, and a wall cloud in Oklahoma and Texas. This same device was used during the spring storm season in 1988 to probe a wall cloud in Texas. The radar was battery powered and highly portable, and thus convenient to deploy from our chase vehicle. The device separated the receding and approaching Doppler velocities in real time and, while the radar was being used, it allowed convenient stereo data recording for later spectral analysis and operator monitoring of the Doppler signals in stereo headphones. This aural monitoring, coupled with the ease with which an operator can be trained to recognize the nature of the signals heard, made the radar very easy to operate reliably and significantly enhanced the quality of the data being recorded. At the end of the 1988 spring season, the radar was modified to include FM-CW ranging and processing. These modifications were based on a unique combination of video recording and FM chirp generation, which incorporated a video camera and recorder as an integral part of the radar. After modification, the radar retains its convenient portability and the operational advantage of being able to listen to the Doppler signals directly. The original mechanical design was unaffected by these additions. During the summer of 1988, this modified device was used at the Langmuir Laboratory at Socorro, New Mexico in an attempt to measure vertical convective flow in a thunderstorm.

  13. Thermal properties and cw-laser operation of the ytterbium doped borate Li6Y(BO3)3

    Single crystals of Yb doped Li6Y(BO3)3 were obtained by Czochralski method. The first laser tests were encouraging. Different parameters have been investigated to improve cw-laser performances. Thermal properties but also ytterbium content, crystal thickness and pump polarisation are reported. The best crystal configuration was determined and led to high power cw-laser tests equal to 2 W output power.

  14. MMW FM-CW ground-based SAR

    Abril, Jordi; Nova, Enrique; Broquetas Ibars, Antoni; Aguasca Solé, Alberto; Romeu Robert, Jordi; Jofre Roca, Lluís; Mencía Oliva, Beatriz; Grajal de la Fuente, Jesús; Pascual Gutiérrez, Juan Pablo; Fernández Ibáñez, Tomás; Tazón Puente, Antonio

    2010-01-01

    This paper presents the design of two ground based synthetic aperture radar (GB-SAR) systems working at 94 and 300 GHz respectively. Frequency-modulated continuous-wave (FM-CW) technique is used for both systems, being described in the first section. Afterwards the first design at 94GHz is presented, explaining its geometry of exploration and describing the architecture of the W-band radar setup. Regarding the integrated receiver system, two models of low noise (LNA) and medium power amplifie...

  15. Experience at Chalk River with a cw electron accelerator

    For several years a group at Chalk River has been studying the behaviour of structures operated in the cw mode under heavy beam loading. Three side-coupled structures, modelled on the LAMPF design, have been built and tests up to 50% beam loading have been performed on two of them. Control systems have been developed to regulate the disturbances arising from high average power in a multi-tank accelerator and procedures worked out to handle beam currents up to 20 mA at 4 MeV. A pancake-coupled structure has been designed for high power operation and results of low power tests on an aluminum model are presented. Tests at high power with a 50 mA electron beam are planned. (author)

  16. Internally-frequency-doubled Yb fiber laser with 15 W CW green output

    Cieslak, Rafal; Clarkson, William Andrew

    2011-01-01

    In this paper we present a high power continuous-wave (CW) green source using a novel approach for frequency doubling of high power CW fiber lasers based on an internal resonant enhancement cavity integrated within the fiber laser resonator. The experimental configuration (shown in Fig. 1) comprised a double-clad fiber with an Yb-doped core in a simple standing-wave resonator. Feedback for lasing was provided by a diffraction grating at one end of the fiber, and by an external cavity containi...

  17. Cw rf operation of the FMIT RFQ

    The 80-MHz RFQ for the Fusion Materials Irradiation Test Facility prototype accelerator has been rf conditioned for cw operation to the design field level of 17.5 MV/m (1.68 x Kilpatrick limit). Experimental results and operating experience will be discussed

  18. IMPROVED OPERATION OF A CW YLF LASER

    Di Lieto, A.; A. Neri; Minguzzi, P.; F. POZZI; M. Tonelli; Jenssen, H.

    1991-01-01

    We developed a cw laser in the 2 µm region operating at liquid-nitrogen (77 K) and at dry ice temperature (210K) pumped by the 514 µm line of Ar+ laser. Also we observed two walenghts (670 mm, 890 mm) that are significantly correlated with laser emission.

  19. SINGLE PULSE AND CW MULTIPLY DOPED Ho : YAG AND Ho : YLF LASER

    Kalisky, Y.; Kagan, J.; Sagie, D.; Lotem, H.

    1987-01-01

    A comparison of the laser performance of the 5I7 ≫5I8 transition at 2.1 micron in multiply doped Ho :YLF and Ho :YAG both in CW and pulsed operating modes is reported. CW operation was carried out at liquid nitrogen temperature, while the pulsed laser was operated in the temperature range from 86K to 220K. In bath YAG and YLF, the laser threshold shows a fast rise with temperature. The total laser power at high pumpimg levels gradually decreases with temperature in YAG. In YLF, however, the l...

  20. Analysis of the output mode from 60 GHz, 200 kW pulsed and CW gyrotrons

    A Varian 60 GHz, CW gyrotron has recently been operated at power levels up to 200 kW CW. The tube employs a TE011/TE021 complex interaction cavity which inhibits mode competition by the TE221 mode with the desired TE021 mode. The output mode of the cavity is nominally in the TE02 circular waveguide mode in overmoded waveguide. Since the output waveguide also serves as the gyrotron collector, mode conversion occurs in the taper sections and gaps incorporated into the collector. Measurements of the mode conversion on a 60 GHz, 200 kw, 100 ms pulse tube, have been made and compared with similar measurements on the 60 GHz. 200 kW, CW gyrotron. These measurements indicated that the CW tube had significantly more conversion of the TE02 mode into other TE/sub on/ modes than did the pulse tube. Current design work is aimed at reducing the mode conversion of the CW design to the same levels as the pulse design (less than or equal to 10% mode converison)

  1. Development of voids in pulsed and CW- driven reactive plasmas with large nanoparticle density

    This contribution deals with the nanoparticle distribution inside of plasma with large nanoparticle density. In particular, the formation of voids i.e. dust-free regions in pulsed and CW discharge regime is analyzed. The discharge was ignited in a mixture of argon and acetylene in the conditions favorable for nanoparticles’ formation and growth. The temporal evolution of the spatial distribution of nanoparticles during their growth is studied experimentally by means of a laser light scattering technique. The experimental results show that the void expands much faster in the case of pulsed plasma than in the CW plasma operated for the same gas mixture and at the same (average) input power. In the CW plasma, we observed a rapid expansion of the void after some tens of minutes, whereas the corresponding process in the pulsed plasma occurred after some tens of seconds. (paper)

  2. An X-band solid-state FM-CW weather radar

    Ligthart, L. P.; Nieuwkerk, L. R.

    1990-12-01

    FM-CW radar has grown to a mature state owing to new breakthroughs in microwave and computer hardware. Applications of FM-CW radar so far have been mainly in the field of tropospheric research, meteorology and ship navigation. The paper describes a radar to be used for rain-rate determination and rain-cell contouring. The central themes are system fundamentals, system design and construction, and real-time processing of the radar. The new radar is purely solid state, with a CW power of 1 watt. Owing to the use of X-band frequencies, the radar waves need to be corrected for spatial expansion and for rain-induced attenuation along the radar path, using real-time processing. Results demonstrate the potential capability for suppressing coherent ground clutter as well as for detecting rain cells.

  3. Concepts for the JLab Ampere-Class CW Cryomodule

    Rimmer, Robert; Henry, James; Hicks, William R; Preble, Joseph P; Stirbet, Mircea; Wang, Haipeng; Wilson, Katherine; Wu, Genfa

    2005-01-01

    We describe the concepts and developments underway at JLab as part of the program to develop a new CW cryomodule capable of transporting ampere-level beam currents in a compact FEL. Requirements include real-estate gradient of at least 10 MV/m and very strong HOM damping to push BBU thresholds up by two or more orders of magnitude compared to existing designs. Cavity shape, HOM damping, power couplers, tuners etc. are being designed and optimized for this application. Cavity considerations include a large iris for beam halo, low-RF losses, HOM frequencies and Q's, low peak surface fields, field flatness and microphonics. Module considerations include high packing factor, low static heat leak, image current heating of beam-line components, cost and maintainability. This module is being developed for the next generation ERL based high power FELs but may be useful for other applications such as electron cooling, electron-ion colliders, industrial processing etc.

  4. Parametric four-wave mixing using a single cw laser

    Brekke, E

    2013-01-01

    Four-wave mixing can be used to generate coherent output beams, with frequencies difficult to acquire in commercial lasers. Here a single narrow ECDL locked to the two photon 5s-5d transition in rubidium is combined with a tapered amplifier system to produce a high power cw beam at 778 nm and used to generate coherent light at 420 nm through parametric four-wave mixing. This process is analyzed in terms of the the intensity and frequency of the incoming beam as well as the atomic density of the sample. The efficiency of the process is currently limited when on resonance due to the absorption of the 420 nm beam, and modifications should allow a significant increase in output power.

  5. Large Scale CW ECRH Systems: Some considerations

    Turkin Y.

    2012-09-01

    Full Text Available Electron Cyclotron Resonance Heating (ECRH is a key component in the heating arsenal for the next step fusion devices like W7-X and ITER. These devices are equipped with superconducting coils and are designed to operate steady state. ECRH must thus operate in CW-mode with a large flexibility to comply with various physics demands such as plasma start-up, heating and current drive, as well as configurationand MHD - control. The request for many different sophisticated applications results in a growing complexity, which is in conflict with the request for high availability, reliability, and maintainability. ‘Advanced’ ECRH-systems must, therefore, comply with both the complex physics demands and operational robustness and reliability. The W7-X ECRH system is the first CW- facility of an ITER relevant size and is used as a test bed for advanced components. Proposals for future developments are presented together with improvements of gyrotrons, transmission components and launchers.

  6. Caries like lesion initiation in sound enamel following CW CO2 laser irradiation: an in vitro study

    This Study aimed to asses the caries - preventive potential of various CW CO2 laser parameters, and to explore the effect of the laser power density, and the exposure time on the varies inhibition activity. Materials and Methods: Extracted human premolar teeth were irradiated with three different power densities (7.95, 15.9 and 31.8) W/Cm2 for three different exposure times (0.2, 0.4 and 0.8) sec of 10.6 μm CW CO2 laser. All teeth were subjected to caries like lesion formation by 3.5 pH lactic acid for 21 days. The teeth after that were sectioned into ground cross section and the lesion depths were measured using a graticule polarizing microscope. CW CO2 laser preventive treatments inhibit caries like lesion progression up to 44%. This effect was improved with: (1) Increased power density for each of the three exposure times. (2) Decreased exposure time for each of the three power densities within the limits of the previously listed laser parameters. Conclusion: (1) short exposure time of CW CO2 laser results in a significant inhibition of the enamel caries like lesion formation. (2) The inhibitory effect depends upon the power density and the exposure time of the laser beam. (3) The optimal CW CO2 laser parameters used for caries inhibition purpose is achieved with approximately 30 W/Cm2 power density and 0.2 sec exposure time. (author)

  7. An independent distance estimate to CW Leo

    Groenewegen, M A T; Blommaert, J A D L; Cernicharo, J; Decin, L; Gomez, H L; Hargrave, P C; Kerschbaum, F; Ladjal, D; Lim, T L; Matsuura, M; Olofsson, G; Sibthorpe, B; Swinyard, B M; Ueta, T; Yates, J

    2012-01-01

    CW Leo has been observed six times between October 2009 and June 2012 with the SPIRE instrument on board the Herschel satellite. Variability has been detected in the flux emitted by the central star with a period of 639 \\pm 4 days, in good agreement with determinations in the literature. Variability is also detected in the bow shock around CW Leo that had previously been detected in the ultraviolet and Herschel PACS/SPIRE data. Although difficult to prove directly, our working hypothesis is that this variability is directly related to that of the central star. In this case, fitting a sine curve with the period fixed to 639 days results in a time-lag in the variability between bow shock and the central star of 402 \\pm 37 days. The orientation of the bow shock relative to the plane of the sky is unknown (but see below). For an inclination angle of zero degrees, the observed time-lag translates into a distance to CW Leo of 130 \\pm 13 pc, and for non-zero inclination angles the distance is smaller. Fitting the sh...

  8. Installation of a cw radiofrequency quadrupole accelerator at Los Alamos National Laboratory

    Chalk River Laboratories (CRL) has had a long history of cw proton beam development for production of intense neutron sources and fissile fuel breeders. In 1986 CRL and Los Alamos National Laboratory (LANL) entered into a collaborative effort to establish a base technologies program for the development of a cw radiofrequency quadrupole (RFQ). The initial cw RFQ design had 50-keV proton injection energy with 600-keV output energy. The 75-mA design current at 600-keV beam energy was obtained in 1990. Subsequently, the RFQ output energy was increased to 1250 keV by replacing the RFQ vanes, still maintaining the 75-m A design current. A new 250-kW cw klystrode rf power source at 267-MHz was installed at CRL. By April of 1993, 55-mA proton beams had been accelerated to 1250 keV. Concurrent developments were taking place on proton source development and on 50-keV low-energy beam transport (LEBT) systems. Development of a dc, high-proton fraction (≥ 70%) microwave ion source led to utilization of a single-solenoid RFQ direct injection scheme. It was decided to continue this cw RFQ demonstration project at Los Alamos when the CRL project was terminated in April 1993. The LANL goals are to find the current limit of the 1250-keV RFQ, better understand the beam transport properties through the single-solenoid focusing LEBT, continue the application of the cw klystrode tube technology to accelerators, and develop a two-solenoid LEBT which could be the front end of an Accelerator-Driven Transmutation Technologies (ADTT) linear accelerator

  9. A CW 4-rod RFQ for deuterons; Ein Hochleistungs-RFQ-Beschleuniger fuer Deuteronen

    Fischer, P.

    2007-06-15

    A four-rod RFQ accelerator has been built which operates in CW mode with a power consumption of 250 kW. The assembly of a high power RFQ structure requires a precise mechanical alignment and field tuning of the electrode field. The field distribution must be very flat to enable a proper operation with few losses. Adjusting of the field distribution is critical in long structures. (orig.)

  10. CW laser generated ultrasound techniques for microstructure material properties evaluation

    Thursby, Graham; Culshaw, Brian; Pierce, Gareth; Cleary, Alison; McKee, Campbell; Veres, Istvan

    2009-03-01

    Mechanical properties of materials may be obtained from the inversion of ultrasonic Lamb wave dispersion curves. In order to do this broadband excitation and detection of ultrasound is required. As sample size and, in particular, thickness, are reduced to those of microstructures, ultrasound frequencies in the range of the gigahertz region will be required. We look at two possible cw laser excitation techniques which, having far lower peak powers than the more frequently used Q-switched lasers, therefore give a negligible risk of damaging the sample through ablation. In the first method the modulation frequency of a sinusoidally modulated laser is swept over the required range. In the second, the laser is modulated with a series of square pulses whose timing is given by a PRBS (pseudo random binary sequence) in the form of a modified m-sequence.

  11. Discharge conditions for CW and pulse-modulated surface-wave plasmas in low-temperature sterilization

    The discharge conditions required for low-temperature plasma sterilization were investigated using low-pressure surface-wave plasma (SWP). The discharge conditions for both continuous wave (CW) and pulse-modulated SWPs in low-temperature sterilization of Geobacillus stearothermophilus with a population of 1.5 x 106 and 3.0 x 106 were studied by varying the microwave input power from 500 W to 3 kW, and the effective plasma treatment time from 40 to 300 s. Results showed that sterilization was possible in a shorter treatment time using a higher microwave power for both CW and pulse-modulated SWPs. Pulse-modulated SWPs gave effective sterilization at a temperature roughly 10 to 20 deg. C below that of CW SWPs under the same average microwave power

  12. Thermal properties and cw-laser operation of the ytterbium doped borate Li{sub 6}Y(BO{sub 3}){sub 3}

    Sablayrolles, J. [CNRS, Universite de Bordeaux, ICMCB, 87 av. Dr. A. Schweitzer, Pessac F-33608 (France); Jubera, V., E-mail: jubera@icmcb-bordeaux.cnrs.fr [CNRS, Universite de Bordeaux, ICMCB, 87 av. Dr. A. Schweitzer, Pessac F-33608 (France); Delaigue, M.; Manek-Hoenninger, I. [Universite de Bordeaux, CELIA, 351 cours de la Liberation, Talence F-33405 (France); Chaminade, J.-P. [CNRS, Universite de Bordeaux, ICMCB, 87 av. Dr. A. Schweitzer, Pessac F-33608 (France); Hejtmanek, J. [Institute of Physics, Cukrovarnicka 10, 162 53 Prague 6 (Czech Republic); Decourt, R.; Garcia, A. [CNRS, Universite de Bordeaux, ICMCB, 87 av. Dr. A. Schweitzer, Pessac F-33608 (France)

    2009-06-15

    Single crystals of Yb doped Li{sub 6}Y(BO{sub 3}){sub 3} were obtained by Czochralski method. The first laser tests were encouraging. Different parameters have been investigated to improve cw-laser performances. Thermal properties but also ytterbium content, crystal thickness and pump polarisation are reported. The best crystal configuration was determined and led to high power cw-laser tests equal to 2 W output power.

  13. Time analysis and processing of FM-CW signals

    Meta, A; Hoogeboom, P.

    2003-01-01

    Combining frequency modulated continuous wave (FM-CW) teehnology with synthetic aperture radar (SAR) methods leads to a cost-effective, high resolution imaging radar for smallscale applications. There is a growing interest in miniaturized versions of such sysfems. The radar delivers its output in the frequency domain rather then in the time domain so speca/ processing algorithm, which accounts for the typical characteristics of FM-CW radar has to be used. A time domain analysis of a FM-CW SAR...

  14. High-power actively Q-switched single-mode 1342 nm Nd:YVO4 ring laser, injection-locked by a cw single-frequency microchip laser.

    Koch, Peter; Bartschke, Juergen; L'huillier, Johannes A

    2015-11-30

    In this paper we report on the realization of a single-mode Q-switched Nd:YVO4 ring laser at 1342 nm. Unidirectional and single-mode operation of the ring laser is achieved by injection-locking with a continuous wave Nd:YVO4 microchip laser, emitting a single-frequency power of up to 40 mW. The ring laser provides a single-mode power of 13.9 W at 10 kHz pulse repetition frequency with a pulse duration of 18.2 ns and an excellent beam quality (M2 laser, a power of 8.7 W at 671 nm with a pulse duration of 14.8 ns and a beam propagation factor of M2 < 1.1 is obtained. The 671 nm radiation features a long-term spectral width of 75 MHz. PMID:26698762

  15. RF power supply system for CW proton linear accelerators for the energy of 1 GeV and currents up to 30 mA and 300 mA

    The problems of the title facility for electronuclear power engineering are considered. Reaching a high efficiency and reliability of operation are considered as the main problems. Two versions of the RF system design are presented: for accelerators with superconducting resonators and for accelerators with 'warm' resonators and focussing by superconducting solenoidal magnets

  16. Photonic crystal fibers for supercontinuum generation pumped by a gain-switched CW fiber laser

    Larsen, Casper; Noordegraaf, Danny; Hansen, Kim P.;

    2012-01-01

    Supercontinuum generation in photonics crystal fibers (PCFs) pumped by CW lasers yields high spectral power density and average power. However, such systems require very high pump power and long nonlinear fibers. By on/off modulating the pump diodes of the fiber laser, the relaxation oscillations...... of the laser can be exploited to enhance the broadening process. The physics behind the supercontinuum generation is investigated by sweeping the fiber length, the zero dispersion wavelength, and the fiber nonlinearity. We show that by applying gain-switching a high average output power of up to 30 W...

  17. A High-Gradient CW R Photo-Cathode Electron Gun for High Current Injectors

    Robert Rimmer

    2005-05-01

    The paper describes the analysis and preliminary design of a high-gradient photo-cathode RF gun optimized for high current CW operation. The gun cell shape is optimized to provide maximum acceleration for the newly emitted beam while minimizing wall losses in the structure. The design is intended for use in future high-current high-power CW FELs but the shape optimization for low wall losses may be advantageous for other applications such as XFELs or Linear Colliders using high peak power low duty factor guns where pulse heating is a limitation. The concept allows for DC bias on the photocathode in order to repel ions and improve cathode lifetime.

  18. HIGH AVERAGE CURRENT LOW EMITTANCE BEAM EMPLOYING CW NORMAL CONDUCTING GUN.

    CHANG,X.; BEN-ZVI, I.; KEWISCH, J.; PAI, C.

    2007-06-25

    CW normal conducting guns usually do not achieve very high field gradient and waste much RF power at high field gradient compared to superconducting cavities. But they have less trapped modes and wakefields compared to the superconducting cavities due to their low Q. The external bucking coil can also be applied very close to the cathode to improve the beam quality. By using a low frequency gun with a recessed cathode and a carefully designed beam line we can get a high average current and a high quality beam with acceptable RF power loss on the cavity wall. This paper shows that the CW normal conducting gun can be a backup solution for those projects which need high peak and average current, low emittance electron beams such as the Relativistic Heavy Ion Collider (RHIC) e-cooling project and Energy Recovery Linac (Em) project.

  19. Investigation of in-vivo skin autofluorescence lifetimes under long-term cw optical excitation

    Lihachev, A; Ferulova, I; Vasiljeva, K; Spigulis, J [Institute of Atomic Physics and Spectroscopy, University of Latvia, Riga (Latvia)

    2014-08-31

    The main results obtained during the last five years in the field of laser-excited in-vivo human skin photobleaching effects are presented. The main achievements and results obtained, as well as methods and experimental devices are briefly described. In addition, the impact of long-term 405-nm cw low-power laser excitation on the skin autofluorescence lifetime is experimentally investigated. (laser biophotonics)

  20. Plasma density measurements using FM--CW millimeter wave radar techniques

    Modified FM--CW radar techniques using swept millimeter--wave oscillators are useful for determining when a particular density has been reached in a plasma. Narrowband measurements on the Princeton Large Torus (PLT) demonstrate the suitability of these techniques for controlling high-power auxiliary plasma heating systems. Broadband measurements using these same techniques are proposed, by which the density profile could be determined

  1. Plasma density measurements using FM-CW millimeter wave radar techniques

    Modified FM-CW radar techniques using swept millimeter-wave oscillators are useful for determining when a particular density has been reached in a plasma. Narrowband measurements on the Princeton Large Torus (PLT) demonstrate the suitability of these techniques for controlling high-power auxiliary plasma heating systems. Broadband measurements using these same techniques are proposed, by which the density profile could be determined

  2. CW, single-frequency 229nm laser source for Cd-cooling by harmonic conversion

    Kaneda, Yushi; Yarborough, J. M.; Merzlyak, Yevgeny

    2015-02-01

    More than 200mW of CW 229nm for Cd atom cooling application was generated by the 4th harmonic of a single frequency optically pumped semiconductor laser using a 10-mm long, Brewster-cut BBO crystal in an external cavity. With 650mW of 458nm input, 216mW of 229nm power was observed. Conversion efficiency from 458nm to 229nm was more than 33%.

  3. Initial operation of the CW 8X H- ion source discharge

    A pulsed 8Χ source was built and the H- beam current, emittance, and power efficiency were measured. These results were promising, so a cooled, dc version designed for operation at arc power levels up to 30 kW was built. Testing of the CW 8Χ source discharge is underway. The design dc power loading on the cathode surface is 900 W/cm2, considerably higher than achieved in any pervious Penning surface-plasma source (SPS). Thus, the electrode surfaces are cooled with pressurized, hot water. We describe the source and present the initial operating experience and arc test results

  4. Flight, orientation, and homing abilities of honeybees following exposure to 2. 45-GHz CW microwaves

    Gary, N.E.; Westerdahl, B.B.

    1981-01-01

    Foraging-experienced honeybees retained normal flight, orientation, and memory functions after 30 minutes' exposure to 2.45-GHz CW microwaves at power densities from 3 to 50 mW/cm2. These experiments were conducted at power densities approximating and exceeding those that would be present above receiving antennas of the proposed solar power satellite (SPS) energy transmission system and for a duration exceeding that which honeybees living outside a rectenna might be expected to spend within the rectenna on individual foraging trips. There was no evidence that airborne invertebrates would be significantly affected during transient passage through microwaves associated with SPS ground-based microwave receiving stations.

  5. SAR: A novel application for FM-CW radars

    Wit, J.J.M. de; Hoogeboom, P.

    2001-01-01

    For small-scale earth observation applications, there ia a special interest in low-cost, high-resolution imaging radars small, enough to be operated from small, possibly unmanned aircraft. The combination of FM-CW technology and the high resolution of SAR systems should result in such a small, cost-effective imaging radar. In a new project the feasibility of FM-CW SAR is studied. SAR algorithms that take the typical characteristics of FM-CW signals into account will be developed. Furthermore,...

  6. Feasibility study of an FM-CW SAR system

    Wit, J.J.M. de; Hoogeboom, P.; Otten, M.P.G.

    2001-01-01

    There is an increasing interest in low-cost, high-resolution imaging radar systems to be operated from small and maybe even unmanned platforms. Existing imaging systems are generally too heavy for small platforms, or too expensive in day-to-day use to be applied in small-scale civil applications. Combining the compactness of FM-CW radar systems and the high azimuth resolution of SAR systems, an FM-CW SAR sensor could be of interest for small-scale applications. The feasibility of FM-CW SAR in...

  7. Observation of clouds with the newly developed cloud profiling FM-CW radar at 95 GHz

    Takano, Toshiaki; Akita, Ken-ichi; Kubo, Hiroshi; Kawamura, Youhei; Kumagai, Hiroshi; Takamura, Tamio; Nakanishi, Yuji; Nakajima, Teruyuki

    2005-10-01

    We developed a low-power and high-sensitivity cloud profiling radar transmitting frequency modulated continuous wave (FM-CW) at 95 GHz for ground-based observations. Millimeter wave at 95 GHz is used to realize much higher sensitivity than lower frequencies to small cloud particles. An FM-CW type radar realizes similar sensitivity with much smaller output power to a pulse type radar. Two 1m-diameter parabolic antennas separated by 1.4m each other are used for transmitting and receiving the wave. The direction of the antennas is fixed at the zenith. The radar is designed to observe clouds between 0.3 and 20 km in height with a resolution of 15 m. Using the developed millimeter-wave FM-CW radar at 95 GHz, we observed clouds in a campaign observation in Amami Island in March 2003, and on a sail on Mirai, a Japanese scientific research vessel, in September 2004 to January 2005 in the Arctic Ocean and the southwest of the Pacific Ocean. The radar provided good and sensitive data in these long-term observations.

  8. Differential high-resolution stimulated CW Raman spectroscopy of hydrogen in a hollow-core fiber

    Westergaard, Philip G; Petersen, Jan C

    2015-01-01

    We demonstrate sensitive high-resolution stimulated Raman measurements of hydrogen using a hollow-core photonic crystal fiber (HC-PCF). The Raman transition is pumped by a narrow linewidth (<50 kHz) 1064 nm continuous-wave (CW) fiber laser. The probe light is produced by a homebuilt CW optical parametric oscillator (OPO), tunable from around 800 nm to 1300 nm (linewidth ~ 5 MHz). These narrow linewidth lasers allow for an excellent spectral resolution of approximately 10^-4 cm^(-1). The setup employs a differential measurement technique for noise rejection in the probe beam, which also eliminates background signals from the fiber. With the high sensitivity obtained, Raman signals were observed with only a few mW of optical power in both the pump and probe beams. This demonstration allows for high resolution Raman identification of molecules and quantification of Raman signal strengths.

  9. Upgrade and validation on plasma of the Tore Supra CW LHCD generator

    A one year-long major upgrade of the 3.7 GHz Lower Hybrid Current Drive (LHCD) generator for the Tore Supra (TS) tokamak has been performed. It consisted in installing a first series of eight Thales Electron Devices (TED) 700 kW CW klystrons, new CW components and auxiliaries, and in modifying the transmitter control and protection software. Modifications and calibration of the sensors and the RF subsystems were completed as well. Finally, the RF power available in the generator has been increased by 35% and the pulse duration could reach 1000 s. A complete validation and optimization of the klystrons have been performed in 2010 on matched load before the generator could enter into operation. The eight klystrons connected with the Full Active Multijunction (FAM) antenna delivered 3.5 MW/50s in December 2010. The upgrade of the generator and the steps to validate the modifications are described.

  10. Gain-switched CW fiber laser for improved supercontinuum generation in a PCF

    Larsen, Casper; Noordegraaf, Danny; Skovgaard, P.M.W.;

    2011-01-01

    We demonstrate supercontinuum generation in a PCF pumped by a gain-switched high-power continuous wave (CW) fiber laser. The pulses generated by gain-switching have a peak power of more than 700 W, a duration around 200 ns, and a repetition rate of 200 kHz giving a high average power of almost 30 W....... By coupling such a pulse train into a commercial nonlinear photonic crystal fiber, a supercontinuum is generated with a spectrum spanning from 500 to 2250 nm, a total output power of 12 W, and an infrared flatness of 6 dB over a bandwidth of more than 1000 nm with a power density above 5 dBm/nm (3 m......W/nm). This is considerably broader than when operating the same system under CW conditions. The presented approach is attractive due to the high power, power scalability, and reduced system complexity compared to picosecond-pumped supercontinuum sources. © 2011 Optical Society of America....

  11. Polarization-stable dual-color DFB fibre laser system for CW terahertz generation

    Eichhorn, Finn; Petersen, Jens Engholm; Jepsen, Peter Uhd

    tuneable dual-wavelength DFB fibre laser system for continuous wave (CW) THz generation in ultrafast semiconductor photomixers, based on low-temperature grown (LT)-GaAsSb or InP-based MQW structures. The fibre laser system is scalable with respect to output power and is in the latest version fully built of...... polarization maintaining fibre components. The output power of the laser is at maximum 150 mW and has a polarization extinction ratio of better than 20 dB. Besides has the laser system due to its DFB fibre laser oscillator inherently a narrow linewidth. This is required in e.g. gas sensing applications relying...

  12. Development and characterization of a CW ring-type Ti:sapphire laser

    We have designed and developed a CW ring-type Ti:sapphire laser based on the ABCD- matrix analysis. The laser cavity was composed of two concave mirrors, two flat mirrors and a Brewster-cut Ti:sapphire crystal. The folding angle at the concave mirrors was calculated to compensate the astigmatism caused by the a Brewster-cut crystal. At a pump power of 10 W, the output power was 2.37 W and slope efficiency was 28%. The output wavelength could be turned from 743 nm to 770 nm by using a birefringent filter.

  13. Design for a compact CW atom laser

    Power, Erik; Raithel, Georg

    2011-05-01

    We present a design for a compact continuous-wave atom laser on a chip. A 2D spiral-shaped quadrupole guide is formed by two 0.5 mm × 0.5 mm wires carrying 5 A each embedded in a Si wafer; a 1.5 mm × 0.5 mm wire on the bottom layer carries -10 A, producing a horizontal B-field that pushes the guiding channel center above the chip surface. The center-to-center separation between the top wires is varied from 1.6 mm at the start of the guide to 1 mm at the end, decreasing the guide height from ~ 500 μm to ~ 25 μm above the surface as the atoms travel the 70 cm-long guide. The magnetic gradient of the guiding channel gradually increases from ~ 100 G /cm to ~ 930 G /cm . These features result in continuous surface adsorption evaporative cooling and progressive magnetic compression. Spin flip losses are mitigated by a solenoid sewn around the guide to produce a longitudinal B-field. 87Rb atoms are gravitationally loaded into the guide. A far off-resonant light shift barrier at the end of the guide traps the atoms and allows formation of a BEC. Tuning the barrier height to create a non-zero tunneling rate equal to the loading rate completes the implementation of a CW atom laser. Two options for atom interferometry are implemented on the first-generation chip (matter-wave Fabry-Perot interferometer and guide-based Mach-Zehnder interferometer). Current construction status and challenges will be discussed, along with preliminary results.

  14. Development and deployment of CW and pulsed digital low level RF systems for accelerators at RRCAT

    Indus-2, a 2.5 GeV synchrotron radiation source has four 505.8 MHz RF stations to increase the electron beam energy and compensate the synchrotron radiation losses. Each RF station consists of RF cavity, high power RF amplifier and Low Level RF (LLRF) system operating in CW mode. LLRF control system is used to keep the amplitude and phase of the RF field stable in the RF cavity. The LLRF system of Indus-2 was based on analogue technology and had its inherent limitations. In last few years significant up gradation has been done in Indus-2 RF system that includes development, installation and commissioning of CW, Digital LLRF systems in all four RF stations. These Digital LLRF systems have replaced analogue LLRF systems resulting in improved performance of Indus-2 by providing better RF cavity field stability. Digital LLRF systems are more reliable, adaptable, reproducible, precise and immune to noise and drift errors. All these properties play important role in enhancing the quality and increasing the availability of the synchrotron radiation for the users. In this paper, we shall discuss the development, installation and commissioning of CW Digital LLRF systems in Indus-2 and development of pulsed Digital LLRF system for IRFEL. The results of their deployment and experience of optimization for Klystron and solid state RF amplifier will also be presented

  15. 2.5 kW monolithic continuous wave (CW) near diffraction-limited fiber laser at 1080 nm

    Fang, Qiang; Shi, Wei; Qin, Yuguo; Meng, Xiangjie; Zhang, Qihang

    2014-10-01

    We demonstrate a monolithic continuous wave (CW) fiber laser source at 1080 nm, producing 2.5 kW average laser power with near diffraction-limited beam quality (M2 < 1.3). The laser consists of a CW fiber laser oscillator and one double cladding (DC) fiber amplifier in the master oscillator-power amplifier (MOPA) configuration. The optical-to-optical conversion efficiency of the entire laser system with respect to the launched pump power is ~77.9%.

  16. CW and Q-switched performance of a diode end-pumped Yb:YAG laser. Revision 1

    Bibeau, C.; Beach, R.; Ebbers, C.; Emanuel, M.; Skidmore, J.

    1997-02-19

    Using an end-pumped technology developed at LLNL we have demonstrated a Yb:YAG laser capable of delivering up to 434 W of CW power and 226 W of Q-switched power. In addition, we have frequency doubled the output to 515 nm using a dual crystal scheme to produce 76 W at 10 kHz in a 30 ns pulse length.

  17. Experimental results of the 1 MW, 140 GHz, CW gyrotron for W7-X

    For the stellarator Wendelstein 7-X now under construction at IPP Greifswald, Germany, a 10 MW ECRH system is foreseen. A European collaboration has been established between Forschungszentrum Karlsruhe (FZK), IPP Garching/Greifswald, IPF Stuttgart, CRPP Lausanne, CEA Cadarache and TED Velizy, to develop and build the 10 gyrotrons each with an output power of 1 MW for continuous wave (CW) operation. The dependence of the output power and efficiency of the first series tube versus the beam current will be shown in short pulse operation (without depressed collector) and in CW operation (up to 30 minutes, depressed collector operation). RF-field measurements have been performed in order to characterise the output field of the gyrotron and to minimise losses during the transmission to the W7-X device. Several parameters have been optimised (e.g. beam radii, magnetic field) to maximise output power and efficiency of the tube. At FZK site, long pulse tests up to 180 s have been performed (limited by the available power supply), at IPP site the pulse length could be extended to 30 min, both at a power level of 1 MW and high efficiency. (author)

  18. Particle-in-Cell (PIC) simulation of CW industrial heating magnetron.

    Andreev, Andrey D; Hendricks, Kyle J

    2010-01-01

    Modern CW industrial heating magnetrons are capable for producing as high as 300 kW of continuous-wave microwave power at frequencies around 900 MHz and are sold commercially [Wynn et al., 2004]. However, to utilize these magnetrons in some specific research and scientific applications being of interest for the Air Force, the necessary adaptation and redesign are required. It means that the detailed knowledge of principles of their operation and full understanding of how the changes of the design parameters affect their operational characteristics are necessary. We have developed and tested computer model of a 10-vane high-power strapped magnetron, which geometrical dimensions and design parameters are close to those of the California Tube Laboratory's commercially produced CWM-75/100L tube. The computer model is built by using the 3-D Improved Concurrent Electromagnetic Particle-in-Cell (ICEPIC) code. Simulations of the strapped magnetron operation are performed and the following operational characteristics are obtained during the simulation: frequency and mode of magnetron oscillations, output microwave power and efficiency of magnetron operation, anode current and anode-cathode voltage dynamics. The developed computer model of a non-relativistic high-power strapped magnetron may be used by the industrial magnetron community for designing following generations of the CW industrial heating high-power magnetrons. PMID:21721323

  19. 5 MW CW supply system for the ITER gyrotrons Test Facility

    ECH (Electron Cyclotron Heating) for ITER will deliver into the plasma 20 MW of RF power. The procurement of the RF sources will be shared equally between the three following partners: Europe, Japan and Russia. Moreover, Europe decided to develop a RF source capable of 2 MW CW of RF power, based on the design of a coaxial gyrotron with a depressed collector. In order to be able to develop and test these RF sources, a Test Facility (TF) has been built at the CRPP premises in Lausanne (CH). The present paper will first remind the main operation conditions considered to test safely a gyrotron. The power supplies parameters allowing to fulfill these conditions will be reviewed. The core of the paper content will describe the newly installed Main High Voltage Power Supply (MHVPS), to be connected to the gyrotron cathode and capable of -60 kV/80 A-CW. The principle, the characteristics, the on-site test results will be described at the light of the requirements imposed by the gyrotron testing. Particular aspects of the installation and commissioning on-site will be highlighted in comparison with the ITER environment. The synchronized operation of the MHVPS and the BPS (Body Power Supply) on dummy load, piloted through the TF remote control, will be presented and commented. Since the TF supply structure has been built integrating the particular conditions and requirements expected for ITER, a conclusion will summarize the performances obtained at the light of these criteria.

  20. Lithium-ion Battery Parks Protection IC-Cellwise CW1055%赛微CW1055锂电池保护芯片

    曾抗

    2013-01-01

    分析电动工具用锂电池芯片组保护方案的优缺点,对电动工具应用锂电池技术的功能需求和解决方案做了介绍。开发的CW1055适用于3~5节锂电池保护的硬件方案,将电动工具电池保护所需的一系列特殊要求集成到一个专用集成电路中,同时提高系统的稳定性。%Introduce the special functional requirements and protection solutions for Li-battery in DC power tools, and analyzing advantage and weakness of each Li-battery protection solution. The CW1055 is a full function hardware protection solution IC for 3~5 serial connected Li-battery, and integrating the special functional requirements of the DC power tool, at the same time, enhancing the stability of the protection system.

  1. Erbium-doped CW and Q-switched fiber ring laser with fiber grating Michelson interferometer

    Anting Wang(王安廷); Meishu Xing(邢美术); Hai Ming(明海); Jianping Xie(谢建平); Lixin Xu(许立新); Wencai Huang(黄文财); Liang Lü(吕亮); Xiyao Chen(陈曦曜); Feng Li(李锋); Yunxia Wu(吴云霞)

    2003-01-01

    The band-pass characteristic of fiber grating Michelson interferometer is analyzed, which acts as both band-pass filter and Q-switch. An erbium-doped fiber ring laser based on fiber grating Michelson interferometer is implemented for producing single longitudinal mode CW operation with 5 MHz spectral linewidth and up to 6 mW output power. In Q-switched operation, stable fiber laser output pulses with repetition rate of 800 Hz, pulse width of 0.6μs, average power of 1.8 mW and peak power of 3.4 W are demonstrated. The peak power and average power of the Q-switched pulses are varied with the repetition rate.

  2. Simple laboratory methods for quantitative IR measurements of CW agents

    Puckrin, Eldon; Thériault, Jean-Marc; Lavoie, Hugo; Dubé, Denis; Lepage, Carmela J.; Petryk, Michael

    2005-11-01

    A simple method is presented for quantitatively measuring the absorbance of chemical warfare (CW) agents and their simulants in the vapour phase. The technique is based on a standard lab-bench FTIR spectrometer, 10-cm gas cell, a high accuracy Baratron pressure manometer, vacuum pump and simple stainless-steel hardware components. The results of this measurement technique are demonstrated for sarin (GB) and soman (GD). A second technique is also introduced for the passive IR detection of CW agents in an open- air path located in a fumehood. Using a modified open-cell with a pathlength of 45 cm, open-air passive infrared measurements have been obtained for simulants and several classical CW agents. Detection, identification and quantification results based on passive infrared measurements are presented for GB and the CW agent simulant, DMMP, using the CATSI sensor which has been developed by DRDC Valcartier. The open-cell technique represents a relatively simple and feasible method for examining the detection capability of passive sensors, such as CATSI, for CW agents.

  3. CW fiber laser for second harmonic generation:

    Podobnik, Boštjan; Petkovšek, Rok; Možina, Janez; Novak, Vid

    2011-01-01

    We report on a reduced-complexity laser-diode-seeded master-oscillator-power-amplifier setup of a continuous wave fiber laser, with a single-stage ytterbium doped photonic crystal fiber amplifier. The laser is capable of generating up to 7.5 W single-transverse-mode, narrow-linewidth, polarized output suitable for second harmonic generation. The approach used possesses a further power scaling potential.

  4. Feasibility and conceptual design of a C.W. positron source at CEBAF

    Golge, Serkan [Old Dominion Univ., Norfolk, VA (United States)

    2010-08-01

    A feasibility study of a CW positron source for the 12 GeV upgrade at Jefferson Lab (JLAB) is provided. The proposed ≥ 100 nA Continuous Wave (CW) positron source at JLAB has several unique and challenging characteristics: high current incident electron beam at 126 MeV with a high beam power (up to a MW); CW e- beam and CW e+ production. The multiple scattering is a dominant process when creating e+ in a target, which results a large phase space area of the emitted positrons. An admittance study was done at CEBAF to find the maximum phase space area, which is tolerated in the machine. The measured geometrical transverse admittance (A) were Ax =10 and Ay = 5 mm∙mrad at the injector. Energy spread measurement was also done at the ARC1. The fractional spread limit in the ARC1 was measured as δ = 3×10-3 at 653 MeV. By using the optimized results and the CEBAF parameters, three positron injector configurations are proposed; Combined Function Magnet, Two-Dipole and Microtron Dipole configurations. With the assumptions made, by using 126 MeV Ⓧ10 mA e- beam impinging on a 2 mm W target with a 100 μm spot size, we can get up to 3 μA useful e+ current at the North Linac connection. One of the biggest challenges is the target design, which the deposited power is about 60 kW. ILC designs project power deposition up to 13 kW, which would allow the creation of a e+ beam of up to 650 nA otherwise. The results of analytic and monte carlo simulations of the positron production, capture and acceleration are presented. For the target design, a review is presented of solutions for the high power production target. Portions of this dissertation work have been published in two conference proceedings.

  5. Diode-pumped CW and passively Q-switched lasers of Nd:GdLuAG mixed garnet at 1123 nm

    Liu, Yang; Liu, Zhaojun; Zhang, Sasa; Xia, Jinbao; Zhang, Yanmin; Guan, Chen

    2016-03-01

    Diode-pumped CW and passively Q-switched lasers of Nd:GdLuAG mixed garnet at 1123 nm were demonstrated. The maximum average output power of CW operation was 4.13 W. For Q-switched operation, the average output power was 800 mW, the corresponding single pulse energy was 133.8 μJ. The Nd:GdLuAG laser emitting at 1123 nm was obtained for the first time to the best of our knowledge, which proves that the Nd:GdLuAG mixed garnet has a better ability of energy storage than Nd:YAG in 1123 nm oscillation.

  6. Comparison of GSM Modulated and CW Radiofrequency Radiation on Cells

    The aim of our study was to evaluate and compare effect of global system of mobile (GSM) modulation and continuous wave (CW) radiofrequency radiation (RF) on proliferation ability and viability of V79 Chinese hamster lung cells. Previously prepared samples of cells in culture were exposed for 1, 2 and 3 hours both to 915 MHz GSM modulated and to 935 MHz CW RF field in gigahertz transversal electromagnetic mode cell (GTEM-cell). Electric field strength for cells exposed to GSM modulation was set at 10 V/m and for CW exposed cells was 8.2 V/m. Average specific absorption rate (SAR) was calculated to be for GSM 0.23 W/kg and for CW 0.12 W/kg. V79 samples were plated in concentration of 1x104cells/mL. Cell proliferation was determined by cell counts for each hour of exposure during five post-exposure days. Trypan blue exclusion test was used to determine cell viability. In comparison to control cell samples, proliferation of GSM irradiated cells showed significant decrease after 3 hours of exposure on the second and third post-exposure day. CW exposed cell samples showed significant decrease after 3 hours of exposure on the third post-exposure day. Viability of GSM and CW exposed cells did not significantly differ from matched control cell samples. Both applied RF fields have shown similar effect on cell culture growth, and cell viability of V79 cell line. In addition, applied GSM modulated RF radiation demonstrate bigger influence on proliferation of cells. (author)

  7. SRF cavities for CW option of Project X Linac

    Solyak, N.; Gonin, I.; Khabiboulline, T.; Lunin, A.; Perunov, N.; Yakovlev, V.; /Fermilab

    2009-09-01

    Alternative option of Project X is based on the CW SC 2GeV Linac with the average current 1mA. Possible option of the CW Linac considered in the paper includes low energy part consisted of a few families SC Spoke cavities (from 2.5 MeV to 466 MeV) and high energy part consisted of 2 types of elliptical cavities (v/c=0.81 and v/c=1). Requirements and designed parameters of cavities are considered.

  8. Coherent Decomposition of Fully Polarimetric FM-CW Radar Data

    Nakamura, Jun; Aoyama, Kazuyasu; Ikarashi, Muneyuki; Yamaguchi, Yoshio; Yamada, Hiroyoshi

    This paper presents a coherent decomposition scheme for polarimetric SAR data. Coherent decomposition means the decomposition is applied to a single or a few scattering matrix data. Based on the scattering matrix acquired with an FM-CW polarimetric SAR system, we have devised a simple decomposition technique using the coherency matrix for the purpose of identifying scatterers. This paper presents the decomposition technique and some decomposition results obtained by a fully polarimetric FM-CW radar. It is shown the scattering mechanisms are well recovered and the orientation angles of wire scatterer are precisely measured.

  9. ECW/EBW heating and current drive experiment results and prospects for CW operation in QUEST

    A CW phased-array antenna system for electron cyclotron/Bernstein wave heating and current drive (ECWH/CD, EBWH/CD) experiments was developed in the QUEST. The antenna was designed to excite an elliptically polarized pure O-mode wave in oblique injection for the O-X-B mode conversion scenario, and its good performance was confirmed at a high power level. Long pulse discharges with a plasma current of 10 kA and 15 kA were non-inductively attained for 37 s and 20 s, respectively, with only radio frequency (RF) power. Divertor configurations were also obtained in the RF-sustained plasmas. A new operational window for sustained plasma current was observed in the high-density plasma with a higher RF incident power. Two new heating and current drive systems with an 8.56 GHz klystron and a 28 GHz gyrotron are being prepared to conduct CW EBWH/CD experiments in the high-density plasma. (author)

  10. Toward improved software security training using a cyber warfare opposing force (CW OPFOR): the knowledge base design

    Stytz, Martin R.; Banks, Sheila B.

    2005-03-01

    "Train the way you will fight" has been a guiding principle for military training and has served the warfighter well as evidenced by numerous successful operations over the last decade. This need for realistic training for all combatants has been recognized and proven by the warfighter and continues to guide military training. However, to date, this key training principle has not been applied fully in the arena of cyberwarfare due to the lack of realistic, cost effective, reasonable, and formidable cyberwarfare opponents. Recent technological advances, improvements in the capability of computer-generated forces (CGFs) to emulate human behavior, and current results in research in information assurance and software protection, coupled with increasing dependence upon information superiority, indicate that the cyberbattlespace will be a key aspect of future conflict and that it is time to address the cyberwarfare training shortfall. To address the need for a cyberwarfare training and defensive testing capability, we propose research and development to yield a prototype computerized, semi-autonomous (SAF) red team capability. We term this capability the Cyber Warfare Opposing Force (CW OPFOR). There are several technologies that are now mature enough to enable, for the first time, the development of this powerful, effective, high fidelity CW OPFOR. These include improved knowledge about cyberwarfare attack and defense, improved techniques for assembling CGFs, improved techniques for capturing and expressing knowledge, software technologies that permit effective rapid prototyping to be effectively used on large projects, and the capability for effective hybrid reasoning systems. Our development approach for the CW OPFOR lays out several phases in order to address these requirements in an orderly manner and to enable us to test the capabilities of the CW OPFOR and exploit them as they are developed. We have completed the first phase of the research project, which

  11. Collector Failures on 350 MHz, 1.2 MW CW Klystrons at the Low Energy Demonstration Accelerator (LEDA)

    Rees, D.; Roybal, W.; Bradley, J.

    2000-01-01

    We are currently operating the front end of the accelerator production of tritium (APT) accelerator, a 7 MeV radio frequency quadrapole (RFQ) using three, 1.2 MW CW klystrons. These klystrons are required and designed to dissipate the full beam power in the collector. The klystrons have less than 1500 operational hours. One collector has failed and all collectors are damaged. This paper will discuss the damage and the difficulties in diagnosing the cause. The collector did not critically fail...

  12. Applications of KHZ-CW Lidar in Ecological Entomology

    Malmqvist Elin; Brydegaard Mikkel

    2016-01-01

    The benefits of kHz lidar in ecological entomology are explained. Results from kHz-measurements on insects, carried out with a CW-lidar system, employing the Scheimpflug principle to obtain range resolution, are presented. A method to extract insect events and analyze the large amount of lidar data is also described.

  13. Applications of KHZ-CW Lidar in Ecological Entomology

    Malmqvist, Elin; Brydegaard, Mikkel

    2016-06-01

    The benefits of kHz lidar in ecological entomology are explained. Results from kHz-measurements on insects, carried out with a CW-lidar system, employing the Scheimpflug principle to obtain range resolution, are presented. A method to extract insect events and analyze the large amount of lidar data is also described.

  14. Theory of a cw supersonic nitrogen recombination laser

    Quasi-two dimensional model calculations show the possibility to realize a cw atomic nitrogen laser, pumped by the recombination process in rapidly expanded plasma flows. Sufficient gain for lasing is demontrated for stagnation conditions of 13 000 00-1 can be attained. The model is described and some selected results are presented. The effect of the electron heat conduction is discussed

  15. Moscow State University CW race-track microtron status

    Continuous wave (CW) race-track microtron (RTM) with the maximum output energy of 175 MeV and beam current 100 mcA is under construction at the Institute of Nuclear Physics of Moscow State University. This paper presents the specifications for the device, status of its construction, and information on the testing of the injector

  16. Biodegradation of pyrazosulfuron-ethyl by Acinetobacter sp. CW17.

    Wang, Yanhui; Du, Liangwei; Chen, Yingxi; Liu, Xiaoliang; Zhou, Xiaomao; Tan, Huihua; Bai, Lianyang; Zeng, Dongqiang

    2012-03-01

    The pyrazosulfuron-ethyl-degrading bacterium, designated as CW17, was isolated from contaminated soil near the warehouse of the factory producing pyrazosulfuron-ethyl in Changsha city, China. The strain CW17 was identified as Acinetobacter sp. based on analyses of 94 carbon source utilization or chemical sensitivity in Biolog microplates, conventional phenotypic characteristics, and 16S rRNA gene sequencing. When pyrazosulfuron-ethyl was provided as the sole carbon source, the effects of pyrazosulfuron-ethyl concentration, pH, and temperature on biodegradation were examined. The degradation rates of pyrazosulfuron-ethyl at initial concentrations of 5.0, 20.0, and 50.0 mg/L were 48.0%, 77.0%, and 32.6%, respectively, after inoculation for 7 days. The growth of the strain was inhibited at low pH buffers. The chemical degradation occurs much faster at low pH than at neutral and basic pH conditions. The degradation rate of pyrazosulfuron-ethyl at 30°C was faster than those at 20 and 37°C by CW17 strains. Two metabolites of degradation were analyzed by liquid chromatography-mass spectroscopy (LC/MS). Based on the identified products, strain CW17 seemed to be able to degrade pyrazosulfuron-ethyl by cleavage of the sulfonylurea bridge. PMID:22388979

  17. CW-FIT: Group Contingency Effects across the Day

    Wills, Howard P.; Iwaszuk, Wendy M.; Kamps, Debra; Shumate, Emily

    2014-01-01

    This study explored the effects of a group-contingency intervention on student behavior across academic instructional periods. Research suggests group contingencies are evidence-based practices, yet calls for investigation to determine the best conditions and groups suited for this type of intervention. CW-FIT (Class-Wide Function-related…

  18. SAR: A novel application for FM-CW radars

    Wit, J.J.M. de; Hoogeboom, P.

    2001-01-01

    For small-scale earth observation applications, there ia a special interest in low-cost, high-resolution imaging radars small, enough to be operated from small, possibly unmanned aircraft. The combination of FM-CW technology and the high resolution of SAR systems should result in such a small, cost-

  19. Diode-pumped Nd:YAG/LBO CW yellow laser at 588.9 nm

    BU Yi-kun; ZHENG Quan; XUE Qing-hua; JIA Fu-qiang; QIAN Long-sheng

    2005-01-01

    A design of diode-pumped Nd:YAG laser with a single crystal that generates simultaneous laser action at the wavelengths of 1 064 nm and 1 319 nm was presented and continuous-wave (CW) of 588.9 nm was obtained for the first time by use of type-Ⅰ critical phase-matching LBO crystal intracavity sum-frequency mixing.The maximum output power of 62 mW is achieved with an incident pump power of 1.8 W.The optical-to-optical conversion efficiency is up to 3.4%,and the power instability in 24 h is better than ±2.7%.

  20. Analysis and design of CW-LD pumped stable Q-switched laser

    HUANG Xiu-jiang; SUI Zhan; LI Ming-zhong; LIU Yong-zhi; LI Xin

    2004-01-01

    A high power continuous wave (CW) laser diode (LD) pumped acousto-optic Q-switched Nd:YVO4 laser is presented. A short pulse at the 1064 nm is obtained. With a repetition rate of 50 kHz,the maximum average output power of 5.72 W is achieved. The optical conversion efficiency and the slope efficiency are up to 28% and 32.4% respectively. At the repetition rate of 10 kHz and the pulse width of 16.3ns, the maximum single pulse energy of 286 μJ and the peak power of 13kW are acquired. The laser can be used as a signal source in the free-space optical communication. The output signal agrees with the modulate signal well.

  1. CW frequency doubling of 1029 nm radiation Using single pass bulk and waveguide PPLN crystals

    Chiodo, Nicola; Hrabina, Jan; Candela, Yves; Wallerand, Jean-Pierre; Acef, Ouali

    2013-01-01

    Following various works on second harmonic process using periodically poled Lithium Niobate crystals (PPLN), we report on the performances comparison between commercial bulk and waveguide crystals at 1029 nm. We use a continuous wave (CW) amplified Yb doped single fibre laser delivering up to 500mW in single mode regime. In case of bulk crystal we generate 4 mW using 400 mW IR power. The use of waveguide crystal leads to an increase of the harmonic power up to 33mW with input IR power limited to 200mW. Nevertheless, this impressive efficiency was affected by the long term degradation of the non-linear waveguide crystal.

  2. 1 MW, 352.2 MHz, CW and Pulsed RF test stand

    A 1 MW, 352.2 MHz, RF test stand based on Thales make TH 2089 klystron amplifier is being developed at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore for characterization and qualification of RF components, cavities and related subsystems. Provision to vary RF power from 50 kW to 1 MW with adequate flexibility for testing wide range of HV components, RF components and cavities is incorporated in this test stand. The paper presents a brief detail of various power supplies like high voltage cathode bias power supply, modulating anode power supply, filament power supply, electromagnet power supplies and ion pump power supplies along with their interconnections for biasing TH 2089 klystron amplifier. A digital control and interlock system is being developed to realize proper sequence of operation of various power supplies and to monitor the status of crucial parameters in this test set up. This RF test stand will be a unique national facility, capable of providing both CW and pulse RF power for realizing reliable RF power sources for various projects including the development of high energy proton linac under ADSS program of the Department of Atomic Energy. (author)

  3. Diode-pumped CW Tm:GdVO4 laser at 1.9 μm

    Yufeng Li; Baoquan Yao; Yuezhu Wang

    2006-01-01

    @@ A high power cryogenic cooling Tm-doped (2%) GdVO4 laser double-end-pumped by fiber-coupled-diode with the center wavelength of 804.5 nm at 21 ℃ is reported. The highest continuous-wave (CW) power of 2.35 W at 1903 nm is attained at pump power of 24 W. The slope efficiency is 12.5% and the threshold is 3.2 W. Single- and double-end-pumped types are investigated.

  4. Experimental atomic scale investigation of irradiation effects in CW 316SS and UFG-CW 316SS

    Pareige, P.; Etienne, A.; Radiguet, B.

    2009-06-01

    Materials of the core internals of pressurized water reactor (austenitic stainless steels) are subject to neutron irradiation. To understand the ageing mechanisms associated with irradiation and propose life predictions of components or develop new materials, irradiation damage needs to be experimentally investigated. Atomic scale investigation of a neutron-irradiated CW316 SS with the laser pulsed atom probe gives a detailed description of the solute segregation in the austenitic grains. In order to understand the mechanism of solute segregation detected in the neutron-irradiated materials, ion irradiations were performed. These latest irradiations were realized on a CW 316SS as well as on a nanostructured CW 316SS. The study of irradiation effects in a nanograin material allows first, to easily analyse grain boundary segregation and second, to test the behaviour under irradiation of a new nanostructured material. The three aspects of this atomic scale investigation (neutron irradiation effect, model ion irradiation, new nanostructured CW 316 SS) are tackled in this paper.

  5. CW Energy Recovery Operation of XFELs

    Jacek Sekutowicz; S. Bogacz; Dave Douglas; Peter Kneisel; Gwyn P. Wiliams; Massimo Ferrario; Luca Serafini; Ilan Ben-Zvi; James Rose; Triveni Srinivasan-Rao; Patrick Colestock; Wolf-Dietrich Moeller; Bernd Petersen; Dieter Proch; S. Simrock; James B. Rosenzweig

    2003-09-01

    Commissioning of two large coherent light facilities at SLAC and DESY should begin in 2008 and in 2011 respectively. In this paper we look further into the future, hoping to answer, in a very preliminary way, two questions. First: What will the next generation of the XFEL facilities look like ? Believing that super-conducting technology offers several advantages over room-temperature technology, such as high quality beams with highly populated bunches and the possibility of energy recovery or higher overall efficiency, we focus this preliminary study on the superconducting option. From this belief the second question arises: ''What modifications in superconducting technology and in machine design are needed, as compared to the present DESY XFEL, and what kind of R&D program is required over the next few years to arrive at a technically feasible solution with even higher brilliance and increased overall conversion of AC power to photon beam power. In this paper we will very often refer to and profit from the DESY XFEL design, acknowledging its many technically innovative solutions.

  6. RF characteristics of high power waveguide components for cERL and STF

    L-band waveguide components are used at cERL (high power CW) and/or at STF (pulsed high power). Although the applied conditions to the components differ whether they are used at CW or at pulsed high-power, the cooling of the materials inside looks essential at both of them. We report the performance of these rf components such as circulators and dummy loads designed for CW or pulsed high power. (author)

  7. Tests of compact dummy loads designed for 1 MW-CW

    Waveguides have been designed with special corrugations to convert the incident power to a surface wave and then increase the attenuation gradually to absorb the power uniformly. Advantages include small size, minimal reflected power, and fast time response. We describe measurements of the power deposition profile and the total absorption in 31.75 mm waveguide loads designed for 110 and 170 GHz. Loads have been fabricated in dispersion-strengthened copper with internal nickel plating to increase the absorption and external corrugations to improve the water cooling. When 1 MW was incident in several 5 s pulses, about 800 kW was absorbed at 110 GHz in a load 1.8 m long. We also describe small TiO2-coated aluminum tank loads designed to absorb up to 250 kW-CW residual power exiting these waveguide loads. The tank loads have also been used to absorb 1 MW with pulse widths around 0.2 s. We describe special features used to maintain uniformity of the power deposition in the tank walls and to minimize reflections into the input waveguide. A novel low-power technique for measuring total reflected power indicated that 1% or less of the power is reflected from these tank loads. (authors)

  8. Performance Analysis of a High Resolution Airborne FM-CW Synthetic Aperture Radar

    Wit, J.J.M. de; Hoogeboom, P.

    2003-01-01

    Compact FM-CW technology combined with high resolution SAR techniques should pave the way for a small and cost effective imaging radar. A research project has been inìtiated to investigate the feasibility of FM-CW SAR. Within the framework of the project an operational airborne FM-CW SAR demonstrato

  9. Motion Compensation for a High Resolution Ka-Band Airborne FM-CW SAR

    Meta, A; Lorga, J.F.M.; Wit, J.J.M. de; Hoogeboom, P.

    2005-01-01

    Airborne synthetic aperture radar is a promising new application for FM-CW radars. At the IRCTR, an operational demonstrator system has been developed in order to investigate the practicability of FM-CW SAR and to prove that an FM-CW SAR system can be operated in an efficient manner from a small pla

  10. Noise analysis for near-field 3D FM-CW radar imaging systems

    Sheen, David M.

    2015-05-01

    Near field radar imaging systems are used for demanding security applications including concealed weapon detection in airports and other high-security venues. Despite the near-field operation, phase noise and thermal noise can limit performance in several ways. Practical imaging systems can employ arrays with low gain antennas and relatively large signal distribution networks that have substantial losses which limit transmit power and increase the effective noise figure of the receiver chain, resulting in substantial thermal noise. Phase noise can also limit system performance. The signal coupled from transmitter to receiver is much larger than expected target signals. Phase noise from this coupled signal can set the system noise floor if the oscillator is too noisy. Frequency modulated continuous wave (FM-CW) radar transceivers used in short range systems are relatively immune to the effects of the coupled phase noise due to range correlation effects. This effect can reduce the phase-noise floor such that it is below the thermal noise floor for moderate performance oscillators. Phase noise is also manifested in the range response around bright targets, and can cause smaller targets to be obscured. Noise in synthetic aperture imaging systems is mitigated by the processing gain of the system. In this paper, the effects of thermal noise, phase noise, and processing gain are analyzed in the context of a near field 3-D FM-CW imaging radar as might be used for concealed weapon detection. In addition to traditional frequency domain analysis, a time-domain simulation is employed to graphically demonstrate the effect of these noise sources on a fast-chirping FM-CW system.

  11. Power Generation Enhancement by Utilizing Plant Photosynthate in Microbial Fuel Cell Coupled Constructed Wetland System

    Shentan Liu; Hailiang Song; Xianning Li; Fei Yang

    2013-01-01

    In the present study, a new technology that coupled constructed wetland (CW) with microbial fuel cell (MFC) (CW-MFC) was developed to convert solar energy into electricity on the principles of photosynthetic MFC by utilizing root exudates of Ipomoea aquatica as part of fuel. The maximum power density of 12.42 mW m−2 produced from the CW-MFC planted with Ipomoea aquatica was 142% higher than that of 5.13 mW m−2 obtained from the unplanted CW-MFC. The maximum power output for the planted CW-MFC...

  12. Characteristics of the evolution of a plasma generated by radiation from CW and repetitively pulsed CO2 lasers in different gases

    Kanevskii, M. F.; Stepanova, M. A.

    1990-06-01

    The interaction between high-power CW and repetitively pulsed CO2 laser radiation and a low-threshold optical-breakdown plasma near a metal surface is investigated. The characteristics of the breakdown plasma are examined as functions of the experimental conditions. A qualitative analysis of the results obtained was performed using a simple one-dimensional model for laser combustion waves.

  13. Effects of packaging on the performances of high brightness 9xx nm CW mini-bar diode lasers

    Li, Xiaoning; Wang, Jingwei; Feng, Feifei; Liu, Yalong; Yu, Dongshan; Zhang, Pu; Liu, Xingsheng

    2015-02-01

    9xx nm CW mini-bar diode lasers and stacks with high brightness and reliability are desired for pumping fiber lasers and direct fiber coupling applications. For the traditional cm-bar with 1mm-2mm cavity, it can provide CW output power up to 80W-100W and high reliability, whereas the brightness is relatively low. In comparison, mini-bar based diode lasers with 4mm cavity offer a superior performance balance between power, brightness, and reliability. However, the long cavity and large footprint of mini-bar diode laser renders its sensitivity towards thermal stress formed in packaging process, which directly affects the performances of high bright mini-bar diode lasers. In this work, the thermal stress correlating with package structure and packaging process are compared and analyzed. Based on the experiment and analysis results, an optimized package structure of CW 60W 976 nm mini-bar diode lasers is designed and developed which relieves thermal stress.

  14. Optical trapping assembling of clusters and nanoparticles in solution by CW and femtosecond lasers

    Masuhara, Hiroshi

    2015-02-01

    Laser trapping of molecular systems in solution is classified into three cases: JUST TRAPPING, EXTENDED TRAPPING, and NUCLEATION and GROWTH. The nucleation in amino acid solutions depends on where the 1064-nm CW trapping laser is focused, and crystallization and liquid–liquid phase separation are induced by laser trapping at the solution/air surface and the solution/glass interface, respectively. Laser trapping crystallization is achieved even in unsaturated solution, on which unique controls of crystallization are made possible. Crystal size is arbitrarily controlled by tuning laser power for a plate-like anhydrous crystal of l-phenylalanine. The α- or γ-crystal polymorph of glycine is selectively prepared by changing laser power and polarization. Further efficient trapping of nanoparticles and their following ejection induced by femtosecond laser pulses are introduced as unique trapping phenomena and finally future perspective is presented.

  15. Thermo-mechanical design of a CW sweep plate emittance scanner

    A sweep plate emittance scanner for use with high power, continuous wave (CW) beams has been designed, fabricated and commissioned at Northrop Grumman. The design is capable of scanning beams of up to 20 kW beam power with a spot diameter as small as 2 cm. The scanner pod is mounted on a ball screw driven linear bearing table that is driven through the beam by a stepper motor at velocities up to 30 cm/sec. This paper presents the thermo-mechanical analysis of the pod moving through a gaussian beam and the details of the mechanical design of the pod and motion system. Analyses to determine scanner cooling schemes and structural materials are presented. (author)

  16. Study of Physical Properties of SiCw/Al Composites During Unloaded Thermal Cycling

    ZHAO Xin-ming; TIAN zhi-gang; CHENG hua; ZHU Xiao-gang; CHEN Wen-li

    2004-01-01

    The thermal expansion coefficient of SiCw/Al composites squeeze cast during unloaded thermal cycling was determined and analyzed. The study had shown that the thermal expansion coefficient of SiCw/Al composites reduced greatly with temperature raising. The thermal expansion coefficient of artificial ageing treatment SiCw/Al composites during unloaded thermal cycling reduced gradually, while the thermal expansion coefficient of squeezing SiCw/Al composites increased gradually. In addition, the thermal expansion coefficient of SiCw/Al composites reduced drastically with fiber fraction increasing.

  17. Noise considerations for vital signs CW radar sensors

    Jensen, Brian Sveistrup; Jensen, Thomas; Zhurbenko, Vitaliy;

    2011-01-01

    The use of continuous wave (CW) radars for measuring human vital signs have recently received a lot of attention due to its many promising applications like monitoring people at hospitals or infants at home without the need for wired sensors. This paper briefly presents the typical CW radar setup...... and the underlying signal theory for such sensors. Then to point out and especially clarify one of the most important effects aiding the design of vital signs radars (VSR), a more detailed discussion concerning phase noise cancellation (or filtering) by range correlation is given. This discussion...... leads to some general conclusions about which system components are the most critical concerning noise contribution and thus detection accuracy and dynamic range....

  18. CO/sub 2/ laser sustained CW discharge atomic beam source

    A high pressure, supersonic, laser sustained plasma nozzle beam source has been developed for the production of intense (>1019 particles s1-sr-1) beams of atomic and/or radical species having kinetic energies in the range of 1 to 10 eV. A high plasma temperature (10 to 30,000 K) is produced in the throat of a hydrodynamic expansion nozzle by sustaining a cw optical discharge in a gas using a high power cw CO2 laser. Gas mixtures are expanded through the nozzle/discharge region creating energetic atoms and molecules. An oxygen atom beam has been produced with a kinetic energy of 2 to 3 eV and an intensity of approx. 1018 O-atoms s-1sr-1. O-atom collisions (1 eV) from an uncharacterized nickel surface shows strong specular scattering with approximately 50% energy loss to the surface. Argon beams having kinetic energies between 5 to 10 eV with intensities of >1019 atoms s-1sr-1 have also been produced. 13 refs., 8 figs

  19. Electron Paramagnetic Resonance Imaging: 1. CW-EPR Imaging

    2016-07-01

    Twentieth century bore witness to remarkable scientists whohave advanced our understanding of the brain. Among them,EPR (Electron Paramagnetic Resonance) imaging is particularlyuseful in monitoring hypoxic zones in tumors which arehighly resistant to radiation and chemotherapeutic treatment.This first part of the article covers aspects of CW(continuous wave) imaging with details of FT (pulsed FourierTransform)-EPR imaging covered in Part 2, to be publishedin the next issue of Resonance.

  20. Processing of dual-orthogonal cw polarimetric radar signals

    Babur, G.

    2009-01-01

    The thesis consists of two parts. The first part is devoted to the theory of dual-orthogonal polarimetric radar signals with continuous waveforms. The thesis presents a comparison of the signal compression techniques, namely correlation and de-ramping methods, for the dual-orthogonal sophisticated signals. The novel time-frequency representation of beat signals in frequency modulated continuous wave (FM-CW) polarimetric radar with simultaneous measurement of scattering matrix elements is show...

  1. FM-CW Based Miniature SAR System for Small UAVs

    Hoogeboom, P.; Wit, J.J.M. de; Meta, A.; Figueras, J.

    2005-01-01

    In some earth observation applications there is a requirement for low cost, high performance imaging radar systems small enough to be operated from small, even unmanned, aircraft. The existing pulse radars are non-cost effective complex systems. Therefore they are not suited for these applications. Frequency Modulated Continuous Wave (FM-CW) radar systems are on the other hand generally very compact and relatively cheap to purchase and to use. IRCTR, together with TNO, is investigating the fe...

  2. National CW GeV Electron Microtron laboratory

    Rising interest in the nuclear physics community in a CW GeV electron accelerator reflects the growing importance of high-resolution short-range nuclear physics to future advances in the field. To meet this need, Argonne National Laboratory proposes to build a CW GeV Electron Microtron (GEM) laboratory as a national user facility. The microtron accelerator has been chosen as the technology to generate the electron beams required for the research discussed because of the advantages of superior beam quality, low capital and operating costs and capability of furnishing beams of several energies and intensities simultaneously. A complete technical description of the conceptual design for a six-sided CW microtron (hexatron) is presented. The hexatron and three experimental areas will be housed in a well-shielded complex of existing buildings that provide all utilities and services required for an advanced accelerator and an active research program at a savings of $30 to 40 million. Beam lines have been designed to accommodate the transport of polarized beams to each area. The total capital cost of the facility will be $78.6 million and the annual budget for accelerator operations will be $12.1 million. Design and construction of the facility will require four and one half years. Staged construction with a 2 GeV phase costing $65.9 million is also discussed

  3. Isotope separation by cw infrared laser enhanced reaction

    In laser isotope separation it is widely assumed that the rate of the chemical reaction which involves the laser excited reagents must exceed the interisotope energy transfer rate. This is shown to be an unnecessary constraint on the selection of reactions and experimental conditions. Using deactivation processes to compete with energy transfer between the isotopes, it is shown that isotope selectivity can be preserved even under the difficult conditions of cw single infrared photon excitation. The principle is demonstrated by showing bromine isotope selectivity in the radical chain chlorination of methyl bromide in a low pressure discharge-flow reactor intracavity to a CO2 laser. Thermal, VV, and chemical scrambling effects are shown to be unimportant with proper experimental design. Bromine isotope enrichment is limited to 9 or approx. =5% by the small vibrational rate enhancement of the near-thermoneutral hydrogen abstraction. The temperature dependence of the enrichment is studied and the difficulty in assigning the increased reactivity to a particular vibrational mode is discussed. The energy cost for this particular isotopic enrichment is calculated (6 keV/product molecule) to demonstrate that although energy is wasted by the deactivation process, the flexibility this technique offers in terms of permitting the use of cw (large throughput) ir (efficient) lasers outweighs the above effect. The use of cw techniques allows changes in reactivity of less than 1% to be readily observed

  4. Status of the Project-X CW Linac Design

    Ostiguy, J-F.; Solyak, N.; Berrutti, P.; Carneiro, J.P.; Lebedev, V.; Nagaitsev, S.; Saini, A.; Stheynas, B.; Yakovlev, V.P.; /Fermilab

    2012-05-01

    Project-X is a proposed proton accelerator complex at Fermilab that would provide particle beams to support a diversified experimental program at the intensity frontier. As currently envisioned, the complex would employ a CW superconducting linac to accelerate a 1 mA average, 5 mA peak H{sup -} beam from 2.1 MeV to 3 GeV. A second superconducting linac, operating in pulsed mode would ultimately accelerate a small fraction of this beam up to 8 GeV. The CW linac is based on five families of resonators operating at three frequencies: half-wave (1 family at 162.5 MHz), spoke (2 families at 325 MHz) and elliptical (2 families at 650 MHz). Accelerating and focusing elements are assembled in cryomodules separated by short warm sections. A long open region ({approx} 15 m) allows beam extraction at 1 GeV in support of a nuclear experimental program. In this paper, we present the latest iteration of the CW linac baseline lattice. We also briefly compare it to an alternative where the 162.5 half-wave resonators are replaced with 325 MHz spoke resonators.

  5. GeV C.W. electron microtron design report

    Rising interest in the nuclear physics community in a GeV C.W. electron accelerator reflects the growing importance of high-resolution short-range nuclear physics to future advances in the field. In this report major current problems are reviewed and the details of prospective measurements which could be made with a GeV C.W. electron facility are discussed, together with their impact on an understanding of nuclear forces and the structure of nuclear matter. The microtron accelerator has been chosen as the technology to generate the electron beams required for the research discussed because of the advantages of superior beam quality, low capital and operating cost and capability of furnishing beams of several energies and intensities simultaneously. A complete technical description of the conceptual design for a 2 GeV double-sided C.W. electron microtron is presented. The accelerator can furnish three beams with independently controlled energy and intensity. The maximum current per beam is 100 μamps. Although the precise objective for maximum beam energy is still a subject of debate, the design developed in this study provides the base technology for microtron accelerators at higher energies (2 to 6 GeV) using multi-sided geometries

  6. Development program for a 200 kW, CW, 28 GHz gyroklystron. Final report, April 1976-September 1980

    The objective of this program was to develop a microwave amplifier or oscillator capable of producing 200 kW, CW power output at 28 GHz. The use of the gyrotron or cyclotron resonance interaction was pursued. A room temperature hollow core solenoid magnet with an iron case was designed to produce the magnetic field required for electron cyclotron resonance. Three pulsed gyroklystron amplifiers were built providing increasing stable output powers of 6, 65 and 76 kW. A back-up pulsed gyrotron oscillator produced 248 kW. A ceramic cone broadband water load was developed. Tests are described for the various tubes that were developed

  7. Performance of a 967 nm CW diode end-pumped Er:GSGG laser at 2.79 Micrometer

    Wu, Z H; Wang, S Z; Luo, J Q; Li, X L; Huang, L; Hu, A L; Tang, Y Q; Guo, Q

    2012-01-01

    We demonstrated a 967 nm diode end-pumped Er:GSGG laser operated at 2.794 Micrometer with spectrum width 3.6 nm in the continuous wave(CW) mode. The maximum output power of 440 mW is obtained at an incident pumping power of 3.4 W, which corresponds to an optical-to-optical efficiency of 13% and slope efficiency of 13.2%. The results suggest that short cavity and efficient cooling setup for crystal are advantageous to improve laser performance.

  8. Mathematical modeling of sealed off CW CO/sub 2/ laser

    The reported work presents the mathematical modeling and experimental study of an axial discharge sealed off CW CO/sub 2/ laser. The equations relating the modes energy verses intra-cavity optical intensities in equilibrium are used for modeling. It is based on the four-temperature model. An energy balance equation involving the terms of power loading, temperature of discharge tube walls and optical power removed, is derived and the variation in the output power as the parameters involved in the energy balance equation are varied, is predicted using the model. The derived equations are then programmed in the C++ and data obtained is plotted in excel. The output power as a function of tube wall temperature and discharge current has been measured experimentally as well as by using model. The experimental and predicted results are then compared and are found in accordance. In addition to this the laser is also operated in pulsed mode and the pulse energy as a function of pulsed repetition rate is measured. The efficiency of the laser is also calculated experimentally as well as theoretically. The energy and power measurements are performed using P-444 Pyroelectric probe and P-444 with PH-30 power Head (Digi Rad Division of Terahertz Technologies inc.) respectively. (author)

  9. Analysis of features of water circulating system in Daya Bay Nuclear Power Station

    The design features of GNPS water circulating system and the difference between this design and large size inland fossil fired power station are presented. This features have been listed as follows: (1) the CW system has adopted unit type arrangement, (2) in pumping station the drum type rotating screens have been used, (3) the CW pumps are of vertical concrete vobute type pumps, (4) in CW system, chlorination of CW water to a concentration of lppm will be achieved by means of electrolysis of sea water, (5) debris filters will be installed in the CW pipe at the condenser inlet

  10. Power Generation Enhancement by Utilizing Plant Photosynthate in Microbial Fuel Cell Coupled Constructed Wetland System

    Shentan Liu

    2013-01-01

    Full Text Available In the present study, a new technology that coupled constructed wetland (CW with microbial fuel cell (MFC (CW-MFC was developed to convert solar energy into electricity on the principles of photosynthetic MFC by utilizing root exudates of Ipomoea aquatica as part of fuel. The maximum power density of 12.42 mW m−2 produced from the CW-MFC planted with Ipomoea aquatica was 142% higher than that of 5.13 mW m−2 obtained from the unplanted CW-MFC. The maximum power output for the planted CW-MFC could be divided into two parts: the maximum power yield from in the water body was 66.05 KJ Kg−1  , and the maximum power transformation from plant photosynthesis was 2.31 GJ ha−1 year−1. The average COD removal efficiencies were 92.1% and 94.8% in the unplanted CW-MFC and planted CW-MFC, respectively; the average TN removal efficiencies amounted to 54.4% and 90.8% in the unplanted CW-MFC and planted CW-MFC. This research demonstrates that planting Ipomoea aquatica in the CW-MFC achieved a higher power density and nutrient removal of nitrogen simultaneously.

  11. Nano-strip grating lines self-organized by a high speed scanning CW laser

    After a laser annealing experiment on Si wafer, we found an asymmetric sheet resistance on the surface of the wafer. Periodic nano-strip grating lines (nano-SGLs) were self-organized along the trace of one-time scanning of the continuous wave (CW) laser. Depending on laser power, the nano-trench formed with a period ranging from 500 to 800 nm with a flat trough between trench structures. This simple method of combining the scanning laser with high scanning speed of 300 m min-1 promises a large area of nanostructure fabrication with a high output. As a demonstration of the versatile method, concentric circles were drawn on silicon substrate rotated by a personal computer (PC) cooling fan. Even with such a simple system, the nano-SGL showed iridescence from the concentric circles.

  12. Development of the Multifrequency Gyrotron FU CW GV with Gaussian Beam Output

    Tatematsu, Yoshinori; Yamaguchi, Yuusuke; Ichioka, Ryoichi; Kotera, Masaki; Saito, Teruo; Idehara, Toshitaka

    2015-08-01

    Gyrotron FU CW GV has been developed as a multifrequency gyrotron for operation over the frequency range from 162 to 265 GHz at frequencies separated by steps of approximately 10 GHz. The oscillation modes were selected; the radii of the caustic surfaces for the electromagnetic waves of the modes had similar values in the waveguide, and it was therefore expected that these modes would be converted into Gaussian beams by a mode converter. In reality, more than ten modes oscillated and the Gaussian-like beams were radiated. A double-disk window with variable spacing maintains the transmittance through the window at a high level over a wide range of frequencies. Using this window, output powers of more than 1 kW were observed for almost all the expected modes.

  13. High-resolution CW lidar altimetry using repeating intensity-modulated waveforms and Fourier transform reordering.

    Campbell, Joel F; Lin, Bing; Nehrir, Amin R; Harrison, F Wallace; Obland, Michael D

    2014-10-15

    An interpolation method is described for range measurements of high precision and altimetry using repeating intensity-modulated continuous wave (IM-CW) lidar waveforms, where the range is determined by means of a cross-correlation between the digital form of the transmitted signal and the digitized return signal collected by the lidar receiver. This method uses reordering of the array elements in the frequency domain to convert a repeating synthetic pulse signal to single highly interpolated pulse. The computation of this processing is marginally greater than the correlation itself, as it only involves reordering of the correlation in the frequency domain, which makes it possible to implement this in a real time application. It is shown through theoretical arguments and flight-testing that this is a viable method for high-speed interpolated range measurements. Standard deviation is 0.75 m over water with only 350 mw of transmitted power at 2600 m. PMID:25361160

  14. A CW superconducting linac as the proton driver for a medium baseline neutrino beam in China

    Li, Zhihui

    2013-01-01

    In a long-term planning for neutrino experiments in China, a medium baseline neutrino beam is proposed which uses a CW superconducting linac of 15 MW in beam power as the proton driver. The linac will be based on the technologies which are under development by the China-ADS project, but with much weaker requirement on reliability. It is composed of a 3.2-MeV normal conducting RFQ and 5 different types of superconducting cavities. The nominal design energy and current are 1.5 GeV and 10 mA, respectively. The general considerations and preliminary results on the physics design will be presented here. In addition, the alternative designs such as 2.0 GeV and 2.5 GeV as they may be required by the general design can be easily extended from the nominal one.

  15. Research on cw electron accelerators using room-temperature rf structures. Annual report

    Highlights reported include: measurement of the 100 keV chopped beam emittance, completion of installation of the entire 5 MeV injector linac system with all rf power and drive, extensive field mapping of one end magnet, completion of construction of the 12 MeV linac for the racetrack microtron (RTM), installation of most of the control system, and first acceleration of beam to 5 MeV. Plans for completion of the project are discussed. When the RTM is operating, it is expected to have many unique performance characteristics, including the cw nature of the beam, high current, easily variable energy over a wide range, excellent emittance, and small energy spread. Plans for future uses in the areas of nuclear physics, dosimetry research and standards, accelerator development, and free electron laser research are discussed. 19 refs

  16. Experimental results of the 1 MW, 140 GHz, CW gyrotron for W7-X

    A 10 MW ECRH system will be provided by FZK in collaboration with several European associations for the stellarator W7-X. The RF power will be delivered by 10 gyrotrons operating at 140 GHz in CW with 1 MW each. The development of this gyrotron has been performed within a European collaboration in an industrial frame. Two R and D tubes have been built, up to know one serial tube has been passed the acceptance tests. The design of the gyrotron will be described and short pulse and long pulse results of the first serial gyrotron will be discussed. This gyrotron has been successfully operated at more then 900 kW with a pulse length of 30 min. (author)

  17. Keyhole depth instability in case of CW CO2 laser beam welding of mild steel

    N Kumar; S Dash; A K Tyagi; Baldev Raj

    2010-10-01

    The study of keyhole (KH) instability in deep penetration laser beam welding (LBW) is essential to understand welding process and appearance of weld seam defects. The main cause of keyhole collapse is the instability in KH dynamics during the LBW process. This is mainly due to the surface tension forces associated with the KH collapse and the stabilizing action of vapour pressure. A deep penetration high power CW CO2 laser was used to generate KH in mild steel (MS) in two different welding conditions i.e. ambient atmospheric welding (AAW) and under water welding (UWW). KH, formed in case of under water welding, was deeper and narrower than keyhole formed in ambient and atmospheric condition. The number and dimensions of irregular humps increased in case of ambient and under water condition due to larger and rapid keyhole collapse also studied. The thermocapillary convection is considered to explain KH instability, which in turn gives rise to irregular humps.

  18. 11-W CW 100-μm fiber-coupled 971-nm Al-free active region pump source

    Larat, Christian; Auzanneau, Sophie-Charlotte; Calligaro, Michel; Parillaud, Olivier; Krakowski, Michel; Boulant, Benoit; Laugustin, Arnaud; Fillardet, Thierry

    2004-05-01

    Laser diodes at 980 nm have important applications in medicine (surgery, dentistry) and Telecoms for WDM, high bit rate networks (Er or Er/Yb doped fibre amplifiers). These applications need a high coupling efficiency of the source into a fibre. High brightness mini-bars with an emissive length of 2.7 mm have been recently developed. These devices consist of an array of aluminium free active region index guided tapered laser diodes with standard AR/HR coatings. We have improved the performances as a result of a new epitaxial layer and a new mini-bar design. We measure an optical output power of 25W at 40A under CW operation at 15°C. At 25°C and 33A, we obtain 20W CW and the far field along the slow axis has a Gaussian shape, with a low FWHM value of 3.5°. Along the fast axis, the far-field also has a Gaussian shape and a FWHM of 31,5°. To couple this tapered diode laser mini-bar into a 100μm diameter fibre (0.26 numerical aperture), we use a patented collective beam shaping technique for optical coupling. We obtain a coupled power of 11.2W under CW operation at 971 nm, 21°C with an emitted power from the mini-bar of 21.7W, resulting in a coupling efficiency of 52%. The conductively cooled mini-bar, all the optics and the optical fibre connector are assembled into a 82x62x23mm package. To our knowledge this is the highest reported power coupled into 100μm optical fibre from a single laser diode chip using a collective coupling scheme without any array of micro-optics.

  19. THEORY OF A CW SUPERSONIC NITROGEN RECOMBINATION LASER

    Schall, W.

    1980-01-01

    Quasi-two dimensional model calculations show the possibility to realize a cw atomic nitrogen laser, pumped by the recombination process in rapidly expanded plasma flows. Sufficient gain for lasing is demonstrated for stagnation conditions of 13 000 ⩽ To ⩽ 24 000 K and 2 ⩽ Po ⩽ 30 kPa. Location and size of the gain regimes in the flow direction depend on the plasma starting condition. At a wavelength of 0.91 µm values of small signal gain up to 0.6 m-1 can be attained. The model is described ...

  20. Herschel PACS and SPIRE imaging of CW Leo

    Ladjal, D.; Barlow, M.J.; Groenewegen, M. A. T.; Ueta, T.; Blommaert, J. A. D. L.; M.Cohen; Decin, L.; De Meester, W.; Exter, K.; Gear, W. K.; Gomez, H. L.; Hargrave, P.C.; Huygen, R.; Ivison, R. J.; Jean, C.

    2010-01-01

    Herschel PACS and SPIRE images have been obtained over a 30'x30' area around the well-known carbon star CW Leo (IRC +10 216). An extended structure is found in an incomplete arc of ~22' diameter, which is cospatial with the termination shock due to interaction with the interstellar medium (ISM) as defined by Sahai & Chronopoulos from ultraviolet GALEX images. Fluxes are derived in the 70, 160, 250, 350, and 550 um bands in the region where the interaction with the ISM takes place, and this ca...

  1. Motion Compensation for a High Resolution Ka-Band Airborne FM-CW SAR

    Meta, A; Lorga, J.F.M.; Wit, J.J.M. de; Hoogeboom, P.

    2005-01-01

    Airborne synthetic aperture radar is a promising new application for FM-CW radars. At the IRCTR, an operational demonstrator system has been developed in order to investigate the practicability of FM-CW SAR and to prove that an FM-CW SAR system can be operated in an efficient manner from a small platform. The platform used to fly the demonstrator system and the integrated navigation system will be introduced. In addition, the digitalization and the synchronization regarding the navigation sys...

  2. Performance Analysis of a High Resolution Airborne FM-CW Synthetic Aperture Radar

    Wit, J.J.M. de; Hoogeboom, P.

    2003-01-01

    Compact FM-CW technology combined with high resolution SAR techniques should pave the way for a small and cost effective imaging radar. A research project has been inìtiated to investigate the feasibility of FM-CW SAR. Within the framework of the project an operational airborne FM-CW SAR demonstrator is being implemented. Furthermore, a detailed system model is being developed in order to analyze and estimate the performance of the demonstrator.

  3. Development of a High Resolution Airborne Millimeter Wave FM-CW SAR

    Meta, A; Wit, J.J.M. de; Hoogeboom, P.

    2004-01-01

    The combination of compact FM-CW radar technology and high resolution SAR processing techniques should pave the way for the development of a small, lightweight and cost effective imaging radar. In the field of airborne earth observation, SAR is however a novel application for FM-CW radars. At IRCTR a project was started to investigate the practical feasibility of FM-CW SAR. Within the framework of this project a fully operational airborne FM-CW SAR demonstrator system has been developed and t...

  4. Pulsed and CW adjustable 1942 nm single-mode all-fiber Tm-doped fiber laser system for surgical laser soft tissue ablation applications.

    Huang, Yize; Jivraj, Jamil; Zhou, Jiaqi; Ramjist, Joel; Wong, Ronnie; Gu, Xijia; Yang, Victor X D

    2016-07-25

    A surgical laser soft tissue ablation system based on an adjustable 1942 nm single-mode all-fiber Tm-doped fiber laser operating in pulsed or CW mode with nitrogen assistance is demonstrated. Ex vivo ablation on soft tissue targets such as muscle (chicken breast) and spinal cord (porcine) with intact dura are performed at different ablation conditions to examine the relationship between the system parameters and ablation outcomes. The maximum laser average power is 14.4 W, and its maximum peak power is 133.1 W with 21.3 μJ pulse energy. The maximum CW power density is 2.33 × 106 W/cm2 and the maximum pulsed peak power density is 2.16 × 107 W/cm2. The system parameters examined include the average laser power in CW or pulsed operation mode, gain-switching frequency, total ablation exposure time, and the input gas flow rate. The ablation effects were measured by microscopy and optical coherence tomography (OCT) to evaluate the ablation depth, superficial heat-affected zone diameter (HAZD) and charring diameter (CD). Our results conclude that the system parameters can be tailored to meet different clinical requirements such as ablation for soft tissue cutting or thermal coagulation for future applications of hemostasis. PMID:27464121

  5. RF Simulation of the 187 MHz CW Photo-RF Gun Cavity at LBNL

    Huang, Tong-Ming [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2008-12-01

    A 187 MHz normal conducting Photo-RF gun cavity is designed for the next generation light sources. The cavity is capable of operating in CW mode. As high as 750 kV gap voltage can be achieved with a 20 MV/m acceleration gradient. The original cavity optimization is conducted using Superfish code (2D) by Staples. 104 vacuum pumping slots are added and evenly spaced over the cavity equator in order to achieve better than 10-10-Tor of vacuum. Two loop couplers will be used to feed RF power into the cavity. 3D simulations are necessary to study effects from the vacuum pumping slots, couplers and possible multipactoring. The cavity geometry is optimized to minimize the power density and avoid multipactoring at operating field level. The vacuum slot dimensions are carefully chosen in consideration of both the vacuum conduction, local power density enhancement and the power attenuation at the getter pumps. This technical note gives a summary of 3D RF simulation results, multipactoring simulations (2D) and preliminary electromagnetic-thermal analysis using ANSYS code.

  6. Bunch shape measurement of CW heavy-ion beam

    An accurate bunch shape measurement is one of the most important tasks during the fine tuning of multi-cavity accelerators. A device for the measurement of bunch time structure of cw heavy-ion beams with time resolution ∼20 picoseconds was developed, constructed and commissioned at ATLAS which is a 50 MV superconducting heavy-ion linac. The Bunch Shape Monitor (BSM) is based on the analysis of secondary electrons produced by a primary beam hitting a tungsten wire to which a potential of -10 kV is applied. In a BSM the longitudinal distribution of charge of the primary beam is coherently transformed into a spatial distribution of low energy secondary electrons through transverse rf modulation. The distribution of secondary electrons is detected by a chevron MCP coupled to a phosphor screen. The signal image on the screen is measured by use of a CCD camera connected to a PC. This BSM analyzes cw beams rather than pulsed beams studied by a previous device [1]. Design features of the BSM and the beam measurement results are reported

  7. Photometric analysis of the overcontact binary CW Cas

    New CCD photometric observations of overcontact binary CW Cas were carried out in 2004 and 2011. In particular, the light curve obtained in 2004 shows a remarkable O'Connell effect. Compared with light curves in different observing seasons, variations were found. These variations can be explained by dark spot activities on the surface of at least one component. Using the Wilson-Devinney code with a spot model, we find that the photometric solutions confirm CW Cas is a shallow W-subtype overcontact binary with a spotted massive component. Our new determined times of minimum light together with the others published in the literature were analyzed to find a change of orbital period. From the O – C curves, the period of the system shows a cyclic period change (P 3 = 69.9 yr, A 3 = 0.03196 days) superposed on the linear increase. The cyclic variation, if explained as the light-travel time effect, reveals the presence of a tertiary companion.

  8. Photometric Analysis of the Overcontact Binary CW Cas

    Wang, J. J.; Qian, S. B.; He, J. J.; Li, L. J.; Zhao, E. G.

    2014-11-01

    New CCD photometric observations of overcontact binary CW Cas were carried out in 2004 and 2011. In particular, the light curve obtained in 2004 shows a remarkable O'Connell effect. Compared with light curves in different observing seasons, variations were found. These variations can be explained by dark spot activities on the surface of at least one component. Using the Wilson-Devinney code with a spot model, we find that the photometric solutions confirm CW Cas is a shallow W-subtype overcontact binary with a spotted massive component. Our new determined times of minimum light together with the others published in the literature were analyzed to find a change of orbital period. From the O - C curves, the period of the system shows a cyclic period change (P 3 = 69.9 yr, A 3 = 0.03196 days) superposed on the linear increase. The cyclic variation, if explained as the light-travel time effect, reveals the presence of a tertiary companion.

  9. Optimal Signal Processing of Frequency-Stepped CW Radar Data

    Ybarra, Gary A.; Wu, Shawkang M.; Bilbro, Griff L.; Ardalan, Sasan H.; Hearn, Chase P.; Neece, Robert T.

    1995-01-01

    An optimal signal processing algorithm is derived for estimating the time delay and amplitude of each scatterer reflection using a frequency-stepped CW system. The channel is assumed to be composed of abrupt changes in the reflection coefficient profile. The optimization technique is intended to maximize the target range resolution achievable from any set of frequency-stepped CW radar measurements made in such an environment. The algorithm is composed of an iterative two-step procedure. First, the amplitudes of the echoes are optimized by solving an overdetermined least squares set of equations. Then, a nonlinear objective function is scanned in an organized fashion to find its global minimum. The result is a set of echo strengths and time delay estimates. Although this paper addresses the specific problem of resolving the time delay between the first two echoes, the derivation is general in the number of echoes. Performance of the optimization approach is illustrated using measured data obtained from an HP-X510 network analyzer. It is demonstrated that the optimization approach offers a significant resolution enhancement over the standard processing approach that employs an IFFT. Degradation in the performance of the algorithm due to suboptimal model order selection and the effects of additive white Gaussion noise are addressed.

  10. Quasi-CW diode-pumped self-starting adaptive laser with self-Q-switched output.

    Smith, G; Damzen, M J

    2007-05-14

    An investigation is made into a quasi-CW (QCW) diode-pumped holographic adaptive laser utilising an ultra high gain (approximately 10(4)) Nd:YVO(4) bounce amplifier. The laser produces pulses at 1064 nm with energy approximately 0.6 mJ, duration LBO crystal, representing approximately 61% conversion efficiency. This work shows that QCW diode-pumped self-adaptive holographic lasers can provide a useful source of high peak power, short duration pulses with excellent spatial quality and narrow linewidth spectrum. PMID:19546951

  11. Dual-Frequency 780-nm Ti:Sa Laser for High Spectral Purity Tunable CW THz Generation

    Loas, Goulc'Hen; Romanelli, Marco; Alouini, Mehdi

    2014-01-01

    International audience — A two-axis, two-polarization, dual-frequency Ti:Sa laser optimized for high spectral purity CW-THz generation is demonstrated. The laser output power is 50mW. Its mean emission wavelength is optimized around 780nm in order to suit the maximum efficiency of low temperature grown GaAs photomixers. Despite the extremely wide gain bandwidth of Ti:Sa, a proper intracavity filtering design, adapted to this particular laser architecture, enables tunable and single-frequen...

  12. Broadband Fiber Raman Power-Amplifier for Narrow Linewidth Tunable Seed Lasers Used in Spectroscopic Sensing Project

    National Aeronautics and Space Administration — We propose an energy and space efficient high power continuous wave (cw) narrow linewidth broadband fiber Raman amplifier (FRA) with spectrally tunable...

  13. An airborne millimeter-wave FM-CW radar for thickness profiling of freshwater ice

    Yankielun, Norbert E.

    1992-11-01

    The ability to profile rapidly and accurately the structure of freshwater ice down to a thickness of a few centimeters over large surfaces of frozen ponds, lakes, and rivers has wide military, industrial, commercial, and recreational application, including safety and trafficability surveys. A prototype broadband millimeter wave (26.5 to 40 GHz) Frequency Modulated-Continuous Wave (FM-CW) radar, employing real-time data acquisition and Digital Signal Processing (DSP) techniques, was developed for continuously recording the thickness profile of freshwater ice. Thickness resolution is better than 3 cm plus or minus 10 percent, which improves on short-pulse and FM-CW radars operating at frequencies less than 10 GHz. These other radars have a best reported thickness resolution of approximately 10 cm with a plus or minus 10 percent accuracy; this is insufficient because a freshwater ice sheet as thin as 5 cm, floating on water, can be safely traversed by an individual of average weight. System specifications include a 15-dBm output RF (Radio Frequency) power level, a 0.066-second sweep rate and less than a 50 dB Signal-to-Noise Ratio (SNR). This radar was tested on the ground and from a helicopter at heights of up to 7 m above ice surfaces at speeds up to 40 km/hr. Pond and river ice sheets between 3 and 35 cm thick, with and without fresh snow cover, and with minimal surface roughness were profiled. Results showed direct correlation between radar and borehole thickness measurements. Losses from volume scattering by imbedded air bubbles did not significantly affect the system's capability to discern the air/ice and ice/water scattering boundaries.

  14. Modified Range-Doppler Processing for FM-CW Synthetic Aperture Radar

    Wit, J.J.M. de; Meta, A.; Hoogeboom, P.

    2006-01-01

    The combination of compact frequency-modulated continuous-wave (FM-CW) technology and high-resolution synthetic aperture radar (SAR) processing techniques should pave the way for the development of a lightweight, cost-effective, high-resolution, airborne imaging radar. Regarding FM-CW SAR signal pro

  15. Fixed target clutter suppression by using a polarimetric FM-CW radar

    Ligthart, L. P.; Nieuwkerk, L. R.; van Sinttruijen, J. S.

    The Delft FM-CW polarimetric radar is used to demonstrate capabilities of FM-CW radar systems to suppress coherent non-moving radar targets. The approach is based on measurements with multi-state polarizers. Good improvements in clutter suppression can be obtained by using fast switching polarizers for optimum elliptical polarization and dedicated polarimetry processing.

  16. Moving target indication of FM-CW radar for clutter rejection

    Yang, Jian-Yu; Huang, Shun-Ji

    The moving target indication technique of FM-CW radar with symmetric triangular waveform frequency-modulated transmitted signal is proposed in this paper. The derivation of this technique is presented, and a 35 GHz FM-CW radar with 500 MHz frequency sweep bandwidth is developed to realize this technique.

  17. Airborne FM-CW SAR and Integrated Navigation System Data Fusion

    Lorga, J.F.M.; Meta, A.; Wit, J.J.M. de; Mulder, J.A.

    2005-01-01

    The combination of compact FM-CW radar technology and high resolution SAR pro- cessing techniques should pave the way for the development of a small and cost e®ective imaging radar with high resolution. However, airborne SAR is a very novel application for FM-CW radars. In order to investigate the p

  18. Emittance compensation of CW DC-gun photoinjector

    Emittance growth induced by space charge effect is very important, especially for CW DC-gun photoinjector. In this work, the linear space charge force and its effect on electron beam transverse emittance are studied, and the principle and properties of emittance compensation by solenoid are analyzed. The CAEP DC-gun photoinjector with a solenoid is also simulated by code Parmela. Simulated results indicate that the normalized transverse emittance of an 80 pC bunch at the 350 keV DC-gun ex-it is 5.14 mm · mrad. And after compensated by a solenoid, it becomes 1.27 mm · mrad. The emittance of beam is well compensated. (authors)

  19. Operational experience with CW high gradient and high QL cryomodules

    Hovater, J. Curt [JLAB; Allison, Trent L. [JLAB; Bachimanchi, Ramakrishna [JLAB; Daly, Edward F. [JLAB; Drury, Michael A. [JLAB; Lahti, George E. [JLAB; Mounts, Clyde I. [JLAB; Nelson, Richard M. [JLAB; Plawski, Tomasz E. [JLAB

    2014-12-01

    The Continuous Electron Beam Accelerator Facility (CEBAF) energy upgrade from 6 GeV to 12 GeV includes the installation of ten new 100 MV cryomodules (80 cavities). The superconducting RF cavities are designed to operate CW at an accelerating gradient of 19.3 MV/m with a QL of 3×107. The RF system employs single cavity control using new digital LLRF controls and 13 kW klystrons. Recently, all of the new cryomodules and associated RF hardware and software have been commissioned and operated in the CEBAF accelerator. Electrons at linac currents up to 10 ?A have been successfully accelerated and used for nuclear physics experiments. This paper reports on the commissioning and operation of the cryomodules and RF system.

  20. CW-HSTCP: Fair TCP in high-speed networks

    PAN Xue-zeng; SU Fan-jun; L(U) Yong; PING Ling-di

    2006-01-01

    The congestion control mechanisms of the current standard TCP constrain the congestion windows that can be achieved by TCP in high-speed networks, which leads to low link utilization. HSTCP is one solution to solve this problem by modifying the congestion control mechanism to have the characteristics of TCP friendliness in high loss rate environment and high scalability in low loss rate environment. However, experiments revealed that HSTCP has severe RTT unfairness. After analyzing the RTT unfairness in HSTCP with a model, we proposed CW-HSTCP, which added a fair factor to decrease the difference of congestion window caused by different RTT. Fair factor of long RTT flows can cause a sharp window increment that is easy to cause a bursty traffic, so a method called block-pacing was adopted. Simulation results showed that our new proposal could alleviate the RTT unfairness while keeping advantages of HSTCP.

  1. Maximum Available Accuracy of FM-CW Radars

    V. Ricny

    2009-12-01

    Full Text Available This article deals with the principles and above all with the maximum available measuring accuracy analyse of FM-CW (Frequency Modulated Continuous Wave radars, which are usually employed for distance and velocity measurements of moving objects in road traffic, as well as air traffic and in other applications. These radars often form an important part of the active safety equipment of high-end cars – the so-called anticollision systems. They usually work in the frequency bands of mm waves (24, 35, 77 GHz. Function principles and analyses of factors, that dominantly influence the distance measurement accuracy of these equipments especially in the modulation and demodulation part, are shown in the paper.

  2. SUPERPLASTICITY IN SiCw/ZK60 COMPOSITE

    F.Yan,; K. Wu; M. Zhao

    2003-01-01

    The superplastic deformation behavior of SiCw/ZK60 composite was investigated at temperatures ranging from 573K to 723K and at initial strain rates ranging from 8.3× 10-4 S-1 to 8.3× 10-2 S-1. A maximum elongation of 200% with a m-value of 0.35was obtained at 613K and a initial strain rate of 1.67×10-2 S-1. The apparent activation energy (98k J/mol) approximates that for grain boundary diffusion (92k J/mol)in magnesium. It is proposed that the dominant mechanism of superplastic deformation in the present composite is grain boundary sliding accommodated by diffusional transport, besides, interracial sliding plays an important role in the superplastic deformation.

  3. Power

    Bowles, Samuel; Gintis, Herbert

    2007-01-01

    We consider the exercise of power in competitive markets for goods, labour and credit. We offer a definition of power and show that if contracts are incomplete it may be exercised either in Pareto-improving ways or to the disadvantage of those without power. Contrasting conceptions of power including bargaining power, market power, and consumer sovereignty are considered. Because the exercise of power may alter prices and other aspects of exchanges, abstracting from power may miss essential a...

  4. Diode-Pumped Compact cw Frequency-Doubled Nd:YAG Laser in the Watt Range at 473 nm

    李平雪; 李德华; 张治国; 张世文

    2003-01-01

    We report a diode-pumped cw Nd:YAG laser operating on the 4F3/2-4I9/2 transition at 946nm, for which a maximum output power of 4.5 W with a slope efficiency of 21% is achieved at an incident pump power of 26 W.Two LiBsO5 (LBO) crystals of different lengths (3 × 3 × 10mm and 3 × 3 × 15 mm), cut for critical type Ⅰphase matching at room temperature, have been used for intracavity frequency doubling, and through optimization of the structure and elements of the cavity, a maximum single-ended blue output power of 1.1 W has been obtained with an optical conversion efficiency of 4.2%. A stability better than 4.8% with no mode hopping over a period of 2h has been achieved.

  5. Status of the 140 GHz, 10 MW CW transmission system for ECRH on the stellarator W7-X

    The stellarator W7-X, which is currently under construction at IPP Greifswald, Germany, will be equipped with a 10 MW ECRH system working at 140 GHz in CW regime. The microwave power will be generated by 10 gyrotrons delivering 1 MW each and will be transmitted from the gyrotron hall to the W7-X stellarator ports via a fully optical system. The status of the construction of the transmission lines and the design of the launchers is reported. Low-power tests of a prototype system at IPF Stuttgart are reviewed. Now, the first two gyrotrons are operating at IPP Greifswald, and high-power long-pulse tests have started. Measurements on transmission performance, behaviour of the water-cooled mirrors under thermal and microwave loads as well as alignment issues, characteristics of directional couplers, calorimetric loads, and other diagnostics are discussed

  6. Low-cost 7 mW CW 355-nm diode-pumped intracavity frequency-tripled microchip laser

    Aubert, Nicolas; Georges, Thierry; Chauzat, Corinne; Le Bras, Raymond; Féron, Patrice

    2006-02-01

    Low noise CW milliWatt scale UV lasers are needed for many analysis applications in the semiconductor and the biological fields. Intracavity tripling has been widely used to improve the UV output power of Q-switched or modelocked lasers, but no efficient diode-pumped CW UV laser was ever reported. One of the key to success is the use of a monolithic laser structure which both eliminates the birefringence interference issue and facilitates the single frequency operation. The monolithic structure is obtained by optically contacting crystals. It does not require any alignment, reduces the manufacturing cost and improves reliability. The optimization of the amplifying medium and doubling and tripling crystals involves as many parameters as pump absorption, thermal lens, cavity length, 1064 nm mode size, walk-off, acceptance angles, polarizations, phases... The interplay between these parameters will be discussed. Finally, several amplifying media (Nd:YAG and Nd:YVO 4), doubling crystals (KTP, KNbO 3, BBO, BiBO and LBO) and tripling crystals (BBO, BiBO, LBO) were tested. With a 2.4W 808 nm diode pump, several configurations have led to low noise 355 nm single frequency operation exceeding 5 mW. We believe that this power can still be improved.

  7. High power quantum cascade lasers

    We report the most recent state-of-art quantum cascade laser results at wavelengths around 4.8 and 10 μm. At 4.8 μm, a room temperature wall plug efficiency (WPE) of 22 and 15.5% are obtained in pulsed mode and continuous wave (cw) mode, respectively. Room temperature cw output power reaches 3.4 W. The same laser design is able to reach a WPE of 36% at 120 K in pulsed mode. At 10 μm, room temperature average power of 2.2 W and cw power of 0.62 W are obtained. We also explore lasers utilizing the photonic crystal distributed feedback mechanism, and we demonstrate up to 12 W peak power operation at three different wavelengths around 4.7 μm with a waveguide width of 100 μm and diffraction limited beam quality.

  8. Multi-kW cw fiber oscillator pumped by wavelength stabilized fiber coupled diode lasers

    Becker, Frank; Neumann, Benjamin; Winkelmann, Lutz; Belke, Steffen; Ruppik, Stefan; Hefter, Ulrich; Köhler, Bernd; Wolf, Paul; Biesenbach, Jens

    2013-02-01

    High power Yb doped fiber laser sources are beside CO2- and disk lasers one of the working horses of industrial laser applications. Due to their inherently given robustness, scalability and high efficiency, fiber laser sources are best suited to fulfill the requirements of modern industrial laser applications in terms of power and beam quality. Pumping Yb doped single-mode fiber lasers at 976nm is very efficient. Thus, high power levels can be realized avoiding limiting nonlinear effects like SRS. However the absorption band of Yb doped glass around 976nm is very narrow. Therefore, one has to consider the wavelength shift of the diode lasers used for pumping. The output spectrum of passively cooled diode lasers is mainly defined by the applied current and by the heat sink temperature. Furthermore the overall emission line width of a high power pump source is dominated by the large number of needed diode laser emitters, each producing an individual spectrum. Even though it is possible to operate multi-kW cw single-mode fiber lasers with free running diode laser pumps, wavelength stabilizing techniques for diode lasers (e.g. volume holographic gratings, VHG) can be utilized in future fiber laser sources to increase the output power level while keeping the energy consumption constant. To clarify the benefits of wavelength stabilized diode lasers with integrated VHG for wavelength locking the performance of a dual side pumped fiber oscillator is discussed in this article. For comparison, different pumping configurations consisting of stabilized and free-running diode lasers are presented.

  9. Flexible carbon micro-supercapacitors prepared by direct cw-laser writing

    Cai, Jinguang; Watanabe, Akira

    2016-03-01

    Micro-/nano-scale power supply units with high energy and high power densities are critical components for the development of compact miniaturized portable electronic devices. Supercapacitors have attracted many research attentions due to their high power density, robust cycle performance, pollution-free operation, and maintenance-free features. Besides, the properties of small size, light weight, and flexibility are also required. On-chip microsupercapacitors (MSCs) have the potential acting as power supply units in portable devices, due to their simplified packaging processes and compatibility to the integrated circuits. However, the fabrication methods and materials should be cost-effective, scalable, and compatible to current electronic industry. Carbon materials own high specific surface areas, electrochemical stability, and high electrical conductivity, which are critical parameters for high-power supercapacitors. Moreover, the high mechanical tolerance makes them good candidates for flexible wearable devices. Therefore, MSCs based on carbon materials would satisfy the requirements of portable electronics. In this work, we demonstrated the fabrication of carbon MSCs by laser direct writing on commercial polyimide sheets in Ar with lowcost semiconductor cw-laser with a wavelength of 405nm. The obtained structures are macro-nanostructures comprising graphitized and amorphous carbon with relatively smooth surfaces and low resistance, in compared with the structures obtained by laser writing in air. As-prepared micro-supercapacitors show a high capacitance of about 14.9 mF/cm2 at a scanning rate of 10 mV/s, which is comparable to the reported highest capacitance of carbon-based supercapacitors fabricated by pulse-laser writing.

  10. A CW radiofrequency ion source for production of negative hydrogen ion beams for cyclotrons

    A CW 13.56 MHz radiofrequency-driven ion source RADIS for production of H− and D− beams is under development for replacing the filament-driven ion source of the MCC30/15 cyclotron. The RF ion source has a 16-pole multicusp plasma chamber, an electromagnet-based magnetic filter and an external planar spiral RF antenna behind an AlN window. The extraction is a 5-electrode system with an adjustable puller electrode voltage for optimizing the beam formation, a water-cooled electron dump electrode and an accelerating einzel lens. At 2650 W of RF power, the source produces 1 mA of H− (2.6 mA/cm2), which is the intensity needed at injection for production of 200 µA H+ with the filament-driven ion source. A simple pepperpot device has been developed for characterizing the beam emittance. Plans for improving the power efficiency with the use of a new permanent magnet front plate is discussed