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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. 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

  2. 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)

  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. 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)

  8. 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.

  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. 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.

  12. 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.

  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

    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

    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.

  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. 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.

  6. 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.

  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); 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.

  8. 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.

  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. 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).

  7. 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.

  8. 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.

  9. 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)

  10. 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.

  11. 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...

  12. 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

  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.; 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.

  17. 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.

  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. 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)

  20. 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.

  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. 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.

  3. 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

  4. 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

  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. 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.

  18. 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

  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. 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.

  4. 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.

  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. 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%.

  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. 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

  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. 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...

  6. 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,...

  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. 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

  13. 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

  14. 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

  15. 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…

  16. 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-

  17. 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.

  18. 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.

  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. 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.

  1. 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.

  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. 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)

  6. 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.

  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. 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...

  1. 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...

  2. 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

  3. 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

  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. 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.

  12. 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

  13. 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)

  14. 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.

  15. 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

  16. 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.

  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. 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.

  7. 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

  8. 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.

  9. 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.

  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. 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

  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. 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

  18. 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...

  19. 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)

  20. 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.

  1. 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.

  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. 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.

  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

  11. Side-pumped Nd:YVO4 cw laser with grazing-incidence small angle configuration

    Within the existing variety of laser cavity geometries and gain materials there is one combination that is particularly interesting because of its reduced complexity and high efficiency: the edge-pumped slab-laser using grazing-incidence geometry and a gain media with a very high pump absorption cross-section. In this work we studied a diode side-pumped Nd:YVO4 cw laser. We describe a single and a multiple bounce laser configurations. We demonstrate 22 W of multimode output power for 35 watts of pump power with a single pass through the gain media. A high optical-to-optical conversion efficiency of 63% and a slope efficiency of 74% with a very compact and simple Nd:YVO4 cavity that uses joint stability zones was achieved. The beam quality was M2 = 26 x 11 in the horizontal and vertical direction, respectively. With a double pass configuration we achieved 17 watts with a better beam quality of M2 = 3,4 x 3,7, in the horizontal and vertical direction, respectively. (author)

  12. First lasing of the Darmstadt cw free electron laser

    Brunken, M; Eichhorn, R; Genz, H; Gräf, H D; Loos, H; Richter, A; Schweizer, B; Stascheck, A; Wesp, T

    1999-01-01

    The Darmstadt CW FEL designed for wavelengths between 3 and 10 mu m driven by the superconducting electron accelerator S-DALINAC first lased on December 1st, 1996 and has operated thereafter successfully in the wavelength region between 6.6 and 7.8 mu m. The pulsed electron beam employed had a micro pulse length of about 2ps, with a repetition rate of 10 MHz and a peak current of 2.7 A while its energy was varied between 29.6 and 31.5 MeV. A wedged pole hybrid undulator, with 80 periods each of 0.032 m length and a magnetic field strength of 0.15-0.4T, was located in between a 15.01 m long optical cavity equipped with two high reflectivity (99.8) mirrors of 0.05 m diameter. Due to the low beam current special care with respect to the electron and optical beam properties was necessary to meet the stringent conditions in order to reach a minute small signal gain of at least a few percent resulting in amplification. Saturation was obtained after about 2000 repetitions of the photon pulse inside the cavity. The D...

  13. Herschel PACS and SPIRE imaging of CW Leo

    Ladjal, D; Groenewegen, M A T; Ueta, T; Blommaert, J A D L; Cohen, M; Decin, L; De Meester, W; Exter, K; Gear, W K; Gomez, H L; Hargrave, P C; Huygen, R; Ivison, R J; Jean, C; Kerschbaum, F; Leeks, S J; Lim, T L; Olofsson, G; Polehampton, E; Posch, T; Regibo, S; Royer, P; Sibthorpe, B; Swinyard, B M; Vandenbussche, B; Waelkens, C; Wesson, R

    2010-01-01

    Herschel PACS and SPIRE images have been obtained over a 30\\arcmin$\\times$30\\arcmin\\ area around the well-known carbon star CW Leo (IRC +10 216). An extended structure is found in an incomplete arc of $\\sim$22\\arcmin\\ 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 $\\mu$m bands in the region where the interaction with the ISM takes place, and this can be fitted with a modified black body with a temperature of 25$\\pm$3~K. Using the published proper motion and radial velocity for the star, we derive a heliocentric space motion of 25.1 \\ks. Using the PACS and SPIRE data and the analytical formula of the bow shock structure, we infer a de-projected standoff distance of the bow shock of $R_{0} = (8.0 \\pm 0.3) \\times 10^{17}$ cm. We also derive a relative velocity of the star with respect to the ISM of $(106.6 \\pm 8.7)/\\sqrt{n_{\\rm ...

  14. Sea-dumped CW munitions - the European component

    The purpose of this contribution is to outline the European magnitude of sea-dumped CW munitions. Hereby the paper attempts to provide an overview on historical dumping activities, both for conventional and chemical munitions. The potential dangers which might result from these dumping activities are discussed in brief. Among others the differences in deep sea dumping and dumping in shallow waters are evaluated. Further, the presentation will outline and discuss the different technology steps: (a) identification, (b) recovery, (c) transportation and (d) destruction (on- or off-shore), necessary for possible cleaning of dumping sites. Thereafter an evaluation of the different technologies available/applied is performed, in particular on the destruction part. Hereby the already practised experience is displayed. Based upon existing treaty regimes an actual judgment of possible application of treaty provisions for demanding cleaning up operations is discussed. The question if treaty obligations can be used to force cleaning operations is debated. A possible match of the technology package available with the scope/magnitude of the munitions dumping problem is discussed. Hereby the gaps between the size of the problem and the most suitable technologies for recovery and destruction are illustrated. The resulting answers should be regarded as possible technical guidelines for future development activities as well existing limitations to solve the problems. The papers will result in some general guidelines for future prospect on the issues of dumped munitions, in particular chemical munitions under the European context.(author)

  15. Pulse to CW conversion via four-wave mixing

    In addition to the evident advantages of optical phase conjugation, degenerate four-wave mixing also appears as a good candidate for applications in optical communications. It has already been suggested that this process be used for optical signal processing, the realization of mathematical operations such as convolution or correlation or the construction of logical gates as well as bistable components represent some other possible applications. The authors propose another application of degenerate four-wave mixing which is based on pulse reshaping at high pump intensity l/sub p/. It consists of the transformation of a pulse beam into a cw beam. They theoretically investigated the interaction between two constant pump beams and an incident pulse probe in a lossless Kerrlike medium. Under the small-signal approximation, it is known that the reflected pulse can be expressed as the convolution of the incident pulse with the impulse response of the phase conjugate mirror. In the low-efficiency regime, a pulsed incident beam then produces a pulsed reflected beam. In the nonlinear regime, however, the behavior is quite different. Above a critical pump intensity, the reflection is constant and does not depend on the nature of the incident pulse. This can be interpreted as a result of self-oscillations. They present the results of a numerical simulation of the phenomenon showing the transient behavior. The analysis includes pump depletion and nonlinear phase modulation effects. They also investigate the influence of a finite response time of the Kerr medium

  16. FM-CW radar remote sensing of hydrometeors

    Ligthart, L. P.; Vansinttruyen, J. S.

    1988-03-01

    In order to investigate phenomena influencing co-polar attenuation and cross-polar discrimination along earth-space satellite paths and terrestrial radio links at frequencies above 10 GHz, the number density, geometry, and orientation of hydrometeors (rain, snow, hail, melting particles) along the path have to be characterized. The modeling of the melting process, the dielectric properties of melting particles, and fall velocity behavior of hydrometeors for Doppler velocity computation with vertically pointing radars are described. Attention is paid to backward scattering of ellipsoidal hydrometeors for radar polarimetry computations at arbitrary elevation angles, and to forward scattering of spherical hydrometeors for attenuation computations at high frequencies. The multi-parameter FM-CW radar system is able to measure the polarization properties and Doppler velocity spectra of hydrometeors with high resolution in range and reflectivity level. Preliminary results obtained with this radar system are shown, indicating the capabilities of combined Doppler- and polarimetry measurements for classification of hydrometeors along a satellite path.

  17. Selective control of HOD photodissociation using CW lasers

    Manabendra Sarma; S Adhikari; Manoj K Mishra

    2007-09-01

    Selective control of HOD photodissociation (H-O + D ← HOD → H + O-D) has been theoretically investigated using CW lasers with appropriate carrier frequency and |0, 0〉, |0, 1〉 and |0, 2〉 with zero quantum of excitation in the O-H bond and zero, one and two quanta of excitation in the O-D bond as the initial states. Results indicate that the O-H bond in HOD can be selectively dissociated with a maximum flux of 87% in the H + O-D channel from the ground vibrational state |0, 0〉. For the O-D bond dissociation, it requires two quanta of excitation (|0, 2〉) in the O-D mode to obtain 83% flux in the H-O + D channel. Use of a two colour laser set-up in conjunction with the field optimized initial state (FOIST) scheme to obtain an optimal linear combination of |0, 0〉 and |0, 1〉 vibrational states as the initial state provides an additional 7% improvement to flux in the H-O + D channel as compared to that from the pure |0, 1〉 state.

  18. CW/Pulsed H− ion beam generation with PKU Cs-free 2.45 GHz microwave driven ion source

    Circular accelerators used for positron emission tomography (PET, i.e. accelerator used for make radio isotopes) need several mA of CW H- ion beam for their routine operation. Other facilities, like Space Radio-Environment Simulate Assembly (SPRESA), require less than 10 mA pulsed mode H− beam. Caesium free negative hydrogen ion source is a good choice for those facilities because of its compact structure, easy operation and low cost. Up to now, there is no H− source able to produce very intense H− beams with important variation of the duty factor[1]. Recently, a new version of 2.45 GHz microwave H− ion source was designed at PKU, based on lessons learnt from the previous one. This non cesiated source is very compact thanks to its permanent magnet configuration. Special attention was paid on the design of the discharge chamber structure, electron dumping and extraction system. Source test to produce H− ion beams in pulsed and CW mode was carried out on PKU ion source test bench. In CW mode, a 10.8 mA/30keV H− beam with rms emittance about 0.16 π·mm·mrad has been obtained with only 500 W rf power. The power efficiency reaches 21 mA/kW. In pulsed mode with duty factor of 10% (100Hz/1ms), this compact source can easily deliver 20 mA H− ion beam at 35 keV with rms emittance about 0.2 π·mm·mrad when RF power is set at 2.2 kW (peak power). Several hour successive running operation in both modes and totaling more than 200 hours proves its high quality. The outside dimension of this new H− source body is ϕ116 mm × 124 mm, and the entire H− source infrastructure, including rf matching section, plasma chamber and extraction system, is ϕ310 × 180 mm. The high voltage region is limited with in a ϕ310 mm × 230 mm diagram. Details are given in this paper

  19. CW/Pulsed H- ion beam generation with PKU Cs-free 2.45 GHz microwave driven ion source

    Peng, S. X.; Ren, H. T.; Xu, Y.; Zhang, T.; Zhang, A. L.; Zhang, J. F.; Zhao, J.; Guo, Z. Y.; Chen, J. E.

    2015-04-01

    Circular accelerators used for positron emission tomography (PET, i.e. accelerator used for make radio isotopes) need several mA of CW H- ion beam for their routine operation. Other facilities, like Space Radio-Environment Simulate Assembly (SPRESA), require less than 10 mA pulsed mode H- beam. Caesium free negative hydrogen ion source is a good choice for those facilities because of its compact structure, easy operation and low cost. Up to now, there is no H- source able to produce very intense H- beams with important variation of the duty factor[1]. Recently, a new version of 2.45 GHz microwave H- ion source was designed at PKU, based on lessons learnt from the previous one. This non cesiated source is very compact thanks to its permanent magnet configuration. Special attention was paid on the design of the discharge chamber structure, electron dumping and extraction system. Source test to produce H- ion beams in pulsed and CW mode was carried out on PKU ion source test bench. In CW mode, a 10.8 mA/30keV H- beam with rms emittance about 0.16 π.mm.mrad has been obtained with only 500 W rf power. The power efficiency reaches 21 mA/kW. In pulsed mode with duty factor of 10% (100Hz/1ms), this compact source can easily deliver 20 mA H- ion beam at 35 keV with rms emittance about 0.2 π.mm.mrad when RF power is set at 2.2 kW (peak power). Several hour successive running operation in both modes and totaling more than 200 hours proves its high quality. The outside dimension of this new H- source body is ϕ116 mm × 124 mm, and the entire H- source infrastructure, including rf matching section, plasma chamber and extraction system, is ϕ310 × 180 mm. The high voltage region is limited with in a ϕ310 mm × 230 mm diagram. Details are given in this paper.

  20. Design of a 10 MeV normal conducting CW proton linac based on equidistant multi-gap CH cavities

    Li, Zhihui

    2014-01-01

    The continue wave (CW) high current proton linac has wide applications as the front end of the high power proton machines. The low energy part is the most difficult one and there is no widely accepted solution yet. Based on the analysis of the focusing properties of the CW low energy proton linac, a 10 MeV low energy normal conducting proton linac based on equidistant seven-gap Cross-bar H-type (CH) cavities is proposed. The linac is composed of ten 7-gap CH cavities and the transverse focusing is maintained by the quadrupole doublets located between cavities. The total length of the linac is less than 6 meters and the average acceleration gradient is about 1.2 MeV/m. The electromagnetic properties of the cavities are investigated by Microwave Studio. At the nominal acceleration gradient the maximum surface electric field in the cavities is less than 1.3 times Kilpatrick limit, and the Ohmic loss of each cavity is less than 35 kW. The multi-particle beam dynamics simulations are performed with the help of the...

  1. CW-laser-induced morphological changes of a single gold nanoparticle on glass: observation of surface evaporation.

    Setoura, Kenji; Okada, Yudai; Hashimoto, Shuichi

    2014-12-28

    Pulsed-laser heating of colloidal noble-metal nanoparticles in an aqueous solution induces morphological changes such as size reduction. However, the technique suffers disadvantages through polydispersed products. Here, we show that continuous-wave (CW) laser heating of single gold nanoparticles is capable of generating particles of smaller diameters with superb control in terms of exposure time and intensity. We show, based on calculations of particle temperatures under illumination, that surface evaporation below the boiling point of bulk gold occurs, resulting in a gradual diameter decrease in air. In our experiment, a focused illumination of Au NPs through an objective lens of a microscope provided peak-power densities (10(6)-10(7) W cm(-2)) equivalent to that of a typical nanosecond laser. Nevertheless the heating rate under CW laser illumination is much lower than that under pulsed-laser illumination, resulting in better control over nanoparticle heating and related morphological changes. Furthermore, the single-particle study of such heating helps us to clarify the evolution of such changes to a given particle. PMID:25377431

  2. Space-Qualifiable High Reliability Frequency-Stabilized CW Laser Source Project

    National Aeronautics and Space Administration — We propose the development and space qualification of a high reliability frequency-stabilized CW laser source at 1064 nm wavelength region to satisfy the...

  3. Space-Qualifiable High Reliability Frequency-Stabilized CW Laser Source Project

    National Aeronautics and Space Administration — We propose the SBIR Phase II effort to develop and space-qualify a 1.06 micron high reliability frequency-stabilized CW laser source that fully satisfies the...

  4. Two-dimensional and full polarimetric imaging by a synthetic aperture FM-CW radar

    Yamaguchi, Yoshio; Nishikawa, Toru; Sengoku, Masakazu; Boerner, Wolfgang-Martin

    1995-03-01

    This paper applies the principle of radar polarimetry to a synthetic aperture frequency-modulated continuous wave (FM-CW) radar and presents results based on two-dimensional (2-D) full polarimetric imaging. It is shown that the polarimetric target reflection coefficients obtained by the synthetic aperture FM-CW radar are elements of a Sinclair scattering matrix, although the coefficients are derived from a wide band signal. Using the scattering matrix optimization procedure, a 2-D polarimetric imaging experiment (including Co-Pol maximum, minimum, span, and phase imaging) of an orthogonally placed linear target set was successfully carried out in the laboratory. This result demonstrates the validity of X-band (8.2-9.2 GHz) FM-CW radar polarimetry, and it presents a demonstration of a full polarimetric 2-D FM-CW imaging radar system.

  5. An intra-cavity device with a discharge-drived CW DF chemical laser

    Yan, Baozhu; Liu, Wenguang; Zhou, Qiong; Yuan, Shengfu; Lu, Qisheng

    2015-05-01

    The performance parameters of reflecting mirrors such as absorption coefficient or thermal distortion determine the beam quality of the output laser, so the quality of mirrors is one of the most important factors affecting the capability of the whole laser system. At the present time, there was obviously insufficient in test methods for the mirrors performance. The reflection coefficient, absorption coefficient and scattering coefficient of mirrors could be measured by a lot of test methods such as cavity ring-down method, photothermal deflection method, surface thermal lens method and laser calorimetry. But these methods could not test under high power density radiation. So the test data and results could not indicate the real performance in a real laser system exactly. Testing in a real laser system would be expensive and time consuming. Therefore, the test sequence and data would not be sufficient to analyze and realize the performance of mirrors. To examine the performance of mirrors under high power density radiation, the working principle of intra-cavity was introduced in this paper. Utilizing an output mirror with a low output coupling ratio, an intra-cavity could produce high-power density laser in the resonant cavity on the basis of a relatively small scale of gain medium, and the consumption and cost were very low relatively. Based on a discharge-drived CW DF chemical laser, an intra-cavity device was established. A laser beam of 3kw/cm2 was achieved in the resonant cavity. Two pieces of 22.5 degree mirrors and two pieces of 45 degree mirrors could be tested simultaneously. Absorption coefficient and thermal distortion were measured by calorimetry and Hartmann wavefront sensor respectively. This device was simple, convenient, low-maintenance, and could work for a long time. The test results would provide support for process improvement of mirrors.

  6. Modeling and analysis of a 2,4-MW CW magnicon

    This paper compares the results of small-signal theory and three-dimensional computer modeling of the magnicon, a new type of deflection-modulated microwave amplifier that has great potential for high-power, high-efficiency microwave generation. The selection of operating parameters and the theory of operation of the magnicon are also presented. The magnicon uses two circular cavity assemblies which support rotating RF fields. The input cavity assembly deflection-modulates an electron beam into an expanding spiral path, and the output cavity extracts the kinetic energy from the modulated beam. Static magnetic fields in the input cavity assembly confine the beam and establish the loaded Q of the input cavities. Static magnetic fields in the output cavity produce cyclotron motion at frequencies that are multiples of the microwave frequency. The interaction between the cyclotron motion and the rotating RF fields allows for a distributed, rather than concentrated, extraction of the energy in the electron beam. To date, most experimental work on the magnicon has been performed at the USSR Academy of Sciences, where a 915-MHz magnicon has developed a power output of 2.6 MW, a gain of 30 dB, and an efficiency of 73%. Initial modeling of the magnicon has demonstrated the basic physics of the device and indicates that even higher efficiencies may be achievable. As the accelerator community considers RF intensive projects like accelerator transmutation of nuclear waste (ATW) and accelerator production of tritium (APT), which require hundreds of megawatts of continuous-wave RF energy, the high efficiency and high average power of the magnicon make it an attractive candidate for these applications. A modeling effort is currently under way at Los Alamos to predict the efficiency of a 2.4-MW CW magnicon at 700 MHz. The effort includes a small-signal analysis of the input structure and a three-dimensional computer simulation of the entire device

  7. End plug welding of FBTR fuel element by Nd-YAG CW laser

    Currently thin walled SS-316 FBTR fuel element is closed at both ends with SS solid plug using TIG welding at Radiometallurgy Division, Bhabha Atomic Research Centre. This welding is involved with material of non uniform thickness. The tube is thinner whereas solid plug is thicker material. Precise control of welding parameters and positioning of torch is necessary during welding to get satisfactory penetration without any major defect. In order to meet the objective of achieving good quality weld heat input during welding has to be kept minimal. Of late in Radiometallurgy Division, Bhabha Atomic Research Centre Nd-YAG CW laser welding has been introduced for end plug welding of the fuel element. Necessary experiments have been done to evaluate the performance of laser welding process for the welding of FBTR fuel elements. Laser welding of fuel element has been done at different power level and speeds. The depth of penetration, fusion zone shape, overall weld profile and weld bead thickness have been evaluated. The amount of liquid metal formed during welding has been calculated theoretically by fitting the overall weld profile in mathematical function. The weld profile area has been estimated by image analysis technique. From these data, the heat absorption by the weld pool have been calculated and thermal efficiency has been estimated. Attempt has been made to optimize laser welding parameters. (author)

  8. Conditioned taste aversion in rats exposed to 2450 MHz CW microwaves

    Williams, W.; Michaelson, S.M.

    1978-01-01

    The ability of 2450 MHz CW microwaves to induce an aversive response to saccharin was investigated in rats subjected to the following exposure parameters: incident power densities of 10 to 65 mW/cm/sup 2/ for 10 minutes; 20 mW/cm/sup 2/ for 2 hours; and 65 mW/cm/sup 2/ continuously for 1 hour. Sham-irradiated controls were tested simultaneously. Core body temperatures were measured using a rectal probe before and after microwave exposure. Only those animals irradiated continuously at 65 mW/cm/sup 2/ for 1 hour responded with a significantly reduced saccharin intake. The aversive response correlated with a rise of core body temperature to 39.8/sup 0/C or higher. While taste aversions following administration of apomorphine are considered to be the result of gastrointestinal disturbances, such disturbance does not appear to be the primary cause for microwave-induced aversion. More likely, it appears that exposure to certain levels of microwave irradiation induces a stress that is hyperthermic in nature. What effect this hyperthermic condition has on gastrointestinal and biochemical processes cannot be assessed at this time. It appears, however, that when core body temperature is raised to approximately 40/sub 0/C or higher for one hour or more, the physiological and behavioral temperature regulating mechanisms of the animal become sufficiently stressed to produce the observed taste aversion.

  9. Z-scan measurements of single walled carbon nanotube doped acetylenedicarboxylic acid polymer under CW laser

    Zidan, M. D.; Allaf, A. W.; Allahham, A.; AL-Zier, A.

    2016-06-01

    Z-scan measurements of single walled carbon nanotube (SWCNT) doped with acetylenedicarboxylic acid (ADC) polymer are performed using a CW diode laser at 635 nm wavelength with 17 mW power. The nonlinear absorption coefficient (β), nonlinear refractive index (n2), the real and imaginary parts of the third-order nonlinear optical susceptibility (Re χ3), (Im χ3) of the investigated samples are calculated. It was found that the β values decrease with increase in on-axis input intensity I0. Also, these values are found to be proportional with sample concentrations. The excited-state absorption cross sections were calculated to be at σex=5.08×10-14 cm2 for the (SWCNT) and at 15.1×10-14 cm2 for the ADC polymer. It was found that the σex is larger than ground-state absorption cross sections, indicating that the reverse saturable absorption mechanism (RSA) is the dominating mechanism for the observed absorption nonlinearities.

  10. The beam commissioning of a CW high charge state heavy ion RFQ

    Zhu, K.; Lu, Y. R.; Yin, X. J.; Yang, Y. Q.; Gao, S. L.; Wang, Z.; He, Y.; Liu, G.; Zhang, X. H.; Yuan, Y. J.; Zhao, H. W.; Xia, J. W.; Chen, C. E.

    2015-09-01

    The SSC-LINAC project is launched at Institute of Modern Physics in China to develop one new linear accelerator (LINAC) injector for separated sector cyclotron (SSC). It includes a high charge state ion source, a CW RFQ and a DTL section, and is designed to accelerate ions up to 580 keV/u. Now the ion source and the RFQ cavity have been installed in the main hall and the beam commissioning has been carried out. Two kinds of ions have been tested, 16O5+ and 40Ar8+. The experiment result of 16O5+ is: the measured beam current is 180 μA at entrance of RFQ and 150 μA at exit of RFQ. The output energy of 16O5+ is 141.89 keV/u. The measured beam current is 210 μA at entrance of RFQ and 198 μA at exit of RFQ for 40Ar8+. The output energy of 40Ar8+ is 142.78 keV/u. The experiment results agree with the design parameters of RFQ very well. This paper presents: the design consideration of beam dynamics, RF and cooling structure design; measurement of the cold model; high power test of RFQ and beam commissioning result.

  11. The beam commissioning of a CW high charge state heavy ion RFQ

    The SSC-LINAC project is launched at Institute of Modern Physics in China to develop one new linear accelerator (LINAC) injector for separated sector cyclotron (SSC). It includes a high charge state ion source, a CW RFQ and a DTL section, and is designed to accelerate ions up to 580 keV/u. Now the ion source and the RFQ cavity have been installed in the main hall and the beam commissioning has been carried out. Two kinds of ions have been tested, 16O5+ and 40Ar8+. The experiment result of 16O5+ is: the measured beam current is 180 μA at entrance of RFQ and 150 μA at exit of RFQ. The output energy of 16O5+ is 141.89 keV/u. The measured beam current is 210 μA at entrance of RFQ and 198 μA at exit of RFQ for 40Ar8+. The output energy of 40Ar8+ is 142.78 keV/u. The experiment results agree with the design parameters of RFQ very well. This paper presents: the design consideration of beam dynamics, RF and cooling structure design; measurement of the cold model; high power test of RFQ and beam commissioning result

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

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

    2013-05-01

    We demonstrated a 967 nm diode end-pumped Er:GSGG laser operated at 2.794 μm with spectral width 3.6 nm in the continuous wave (CW) mode. A 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 a short cavity and efficient cooling setup for the crystal help to improve laser performance.

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

    We demonstrated a 967 nm diode end-pumped Er:GSGG laser operated at 2.794 μm with spectral width 3.6 nm in the continuous wave (CW) mode. A 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 a short cavity and efficient cooling setup for the crystal help to improve laser performance. (paper)

  14. Natural gas leaks detection by spatial-resolvable-CW-laser-based remote monitoring

    Agishev, R.R.; Bajazitov, R.A.; Galeyev, M.M.; Ismagilow, Z.B. [Kazan State Technical Univ., Tatarstan (Russian Federation). Dept. of Radioelectronic and Quantum Systems

    1996-12-31

    The opportunities of spatial-resolvable atmosphere monitoring and atmospheric pollutions remote chemical analysis based on the CW-laser radiants are investigated. A frequency-responsive processing peculiarities of atmosphere remote sensing signals are described. Application of the mentioned approach for the limited hydrocarbons remote detection and sensing is discussed. The requirements to the CW-LIDAR receiving and radiating systems parameters are formulated. The evaluations of the system sensitivity limit, measurement accuracy and accuracy increase ways are presented.

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

    This joint NBS-Los Alamos project of ''Research on CW Electron Accelerators Using Room-Temperature RF Structures'' began seven years ago with the goal of developing a technology base for cw electron accelerators. In this report we describe our progress during FY 1986 and present our plans for completion of the project. First, however, it is appropriate to review the past contributions of the project, describe its status, and indicate its future benefits

  16. Brane Topological Field Theories and Hurwitz numbers for CW-complexes

    Natanzon, Sergey M.

    2009-01-01

    We expand Topological Field Theory on some special CW-complexes (brane complexes). This Brane Topological Field Theory one-to-one corresponds to infinite dimensional Frobenius Algebras, graduated by CW-complexes of lesser dimension. We define general and regular Hurwitz numbers of brane complexes and prove that they generate Brane Topological Field Theories. For general Hurwitz numbers corresponding algebra is an algebra of coverings of lesser dimension. For regular Hurwitz numbers the Froben...

  17. High Power Thin Disk Laser

    Giesen, Adolf

    2011-01-01

    In this talk, the latest results for thin disk lasers will be presented. Thin disk lasers can be operated in cw-mode as well as in pulsed mode with pulse durations from 100 fs to microseconds. Results from different institutes and companies will be shown demonstrating the power/energy scalability of the thin disk laser design with good beam quality and high efficiency, simultaneously. Several German companies are selling thin disk lasers with up to 16 kW output power (cw) and with up to 1 kW...

  18. Towards the development of a 5 GHz 500 kW CW window for the ITER LHCD system

    Full text of publication follows. The high current drive efficiency of Lower Hybrid waves makes Lower Hybrid Current Drive (LHCD) system a crucial actuator to sustain a substantial fraction of the plasma current in tokamaks [1]. On the technological side, even though the viability of the Passive Active Multijunction launcher concept has been validated in steady-state conditions at 3.7 GHz [2], its scalability to 5 GHz, which is the frequency for the ITER LHCD system, has to be demonstrated. In this context and even if the LHCD system is not part of the construction baseline, the CEA/IRFM is conducting a research/development efforts in order to validate the design and the performances of the critical RF devices of the 5 GHz ITER LHCD system. In the current ITER LHCD design, 20 MW Continuous Wave (CW) of Radio-Frequency power at 5 GHz are expected to be generated and transmitted to the plasma. In order to separate the vacuum vessel pressure from the cryostat waveguide pressure, forty-eight 5 GHz 500 kW CW windows will be assembled at the rear flange of the equatorial port plug. For nuclear safety reasons, forty eight additional windows could be located in the cryostat section, to separate and monitor the cryostat waveguide pressure from the exterior transmission line pressure. Since these windows are identified as being one of the main critical components for the ITER LHCD system [3], two 5 GHz 500 kW / 5 s BeO pill-box type windows prototypes have been manufactured in 2012 by the PMB Company in close collaboration with the CEA/IRFM. Both windows have been validated at low power. This paper reports the thermo-mechanical design and comparisons to experimental RF measurements. The high power tests are foreseen to be carried out in early 2013 in collaboration with NFRI. Results of these tests will also be reported. The development of CW windows is also discussed. [1] Hoang, G.T. et al., 2009 Nucl. Fusion 49 075001; [2] Ekedahl, A. et al. Nucl. Fusion, 50

  19. Performance analysis of the periodic sequence DSSS system against CW interference

    Anquan WEI; Lianfeng SHEN

    2008-01-01

    Based on the brief account of the performance analysis result of the direct sequence spread spectrum (DSSS) system against a single tone continuous wave (CW) interference obtained from the traditional standard Gaussian approximation (SGA) hypothesis, the mathe-matical expression of the interference component of the symbol decision variable in the periodic sequence DSSS system under CW interference was deduced and the actual performance of the periodic sequence DSSS system against CW interference was researched through theoretical analysis and numerical simulations. The results indicate that the interference component of the symbol decision variable in the periodic sequence DSSS system under CW interference operates at a constant level or fluctuate monochromatically, which does not approach the standard Gaussian distribution, and the actual performance of the periodic sequence DSSS system against CW interference is completely different from the analytic result resorted to the standard Gaussian approximation (SGA). The bit error perfor-mance is correlative not only with the interference-signal ratio (ISR), the frequency offset and the phase of the CW interference sensitively, but also with the individual spread spectrum code sequence.

  20. Evaluation of environmental impact from APCA/CW partnership

    This paper examines the APCA/Climate Wise Partnership and its potential energy and environmental impacts. The authors discuss the issues surrounding greenhouse gas emissions from the production of cement, new and future technologies, and the primary drivers and barriers associated with reducing emissions. The APCA/CW Partner actions and the aggregated impacts of these actions that are undertaken through this partnership are examined. These impacts include cost and energy savings and emission reductions for the current year, and estimated for the year 2000. Comparing these impacts to industrial CO2 benchmarks indicate the level of effort and what additionally needs to be accomplished. The current results from this partnership indicate that in the remainder of the industry adopts their level of effort, greenhouse gas emissions can be reduced well below the business-as-usual benchmarks. The US cement industry accounts for about 1.5% of US industrial energy use and about 5% of US industrial carbon dioxide (CO2) emissions. In 1997 Climate Wise and the American Portland Cement Alliance (APCA) embarked upon a unique partnership to turn energy efficiency and pollution prevention into a corporate asset. This partnership consists of the 16 APCA member companies, representing nearly 60% of US cement manufacturing capacity. Climate Wise, working with APCA and industry representatives, developed the cement industry Action Plan Software, reporting workbook, and sample Action Plan. Through these tools, continued technical support, and the hard work of the APCA companies, this partnership is showing positive results. Over half of the APCA Climate Wise partners have submitted Action Plans - detailing a comprehensive array of current and future actions to improve energy efficiency and reduce greenhouse gas emissions. These Action Plans have supplied valuable information about how this industry is reducing energy use and greenhouse gas emissions

  1. Forensic Application of FM-CW and Pulse Radar

    S. K. Koppenjan; R. S. Freeland; M. L. Miller; R. E. Yoder

    2003-01-01

    Ground-penetrating radar (GPR) technology has supplied vital assistance in criminal investigations. However, law enforcement personnel desire further developments such that the technology is rapidly deployable, and that it provides both a simple user interface and sophisticated target identification. To assist in the development of target identification algorithms, our efforts involve gathering background GPR data for the various site conditions and circumstances that often typify clandestine burials. For this study, forensic anthropologists established shallow-grave plots at The University of Tennessee Anthropological Research Facility (ARF) that are specific to GPR research. These plots contain donated human cadavers lying in various configurations and depths, surrounded by assorted construction material and backfill debris. We scanned the plots using two GPR technologies: (1) a multi-frequency synthetic-aperture FM-CW radar (200-700 MHz) (GPR-X) developed by the U.S. Department of Energy's (DOE) Special Technologies Laboratory (STL), Bechtel Nevada (Koppenjan et al., 2000), and (2) a commercial pulse radar (SIR-20) manufactured by Geophysical Survey Systems, Inc. (400 and 900 MHz)(GSSI). The sweep-frequency data show the large biological mass decomposing within the torso as encircled ''hot spots.'' The 400-MHz pulse radar exhibit major horizontal reflectors above the body, with shadow reflectors (horizontal multiples) occurring beneath the body at 60 cm depth. The 400-MHz antenna was able to discern the grave walls and folded tarp covering the lower body. Under these moist, clay-rich conditions, the 900-MHz antenna was able to penetrate slightly beyond 30 cm beneath the concrete layer. However, neither system was able to penetrate beyond a one meter depth in the moist, clay-rich soil (fine, mixed, thermic Typic Paleudalf). Example scans from each system are provided, along with a discussion of the survey protocol and general performance.

  2. Power

    Elmholdt, Claus Westergård; Fogsgaard, Morten

    2016-01-01

    In this chapter, we will explore the dynamics of power in processes of creativity, and show its paradoxical nature as both a bridge and a barrier to creativity in organisations. Recent social psychological experimental research (Slighte, de Dreu & Nijstad, 2011) on the relation between power and...... creativity suggests that when managers give people the opportunity to gain power and explicate that there is reason to be more creative, people will show a boost in creative behaviour. Moreover, this process works best in unstable power hierarchies, which implies that power is treated as a negotiable and...... floating source for empowering people in the organisation. We will explore and discuss here the potentials, challenges and pitfalls of power in relation to creativity in the life of organisations today. The aim is to demonstrate that power struggles may be utilised as constructive sources of creativity. It...

  3. High Power Room Temperature Terahertz Local Oscillator Project

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

  4. EBT-S 28-GHz, 200-kW, CW, mixed-mode, quasi-optical plasma heating system

    The ELMO Bumpy Torus-Scale (EBT-S) 28-GHz, 200-kW, cw, plasma heating system consists of a gyrotron oscillator, an oversized waveguide two-bend transmission system, and a quasi-optical mixed-mode microwave distribution manifold that feeds microwave power to the 24 plasma loads of the EBT-S fusion experiment. Balancing power to the 24 loads of the EBT-S fusion experiment. Balancing power to the 24 loads was achieved by adjusting the areas at 24 coupling irises. System performance is easily measured using system calorimetry. The distribution manifold mixed-mode power transmission, reflection, and loss coefficients are 89%, 6%, and 5%, respectively. The overall system efficiency (plasma power/gyrotron power) is 80%, but with some modifications to the distribution manifold we believe the ultimate efficiency can approach 90%. The system reliability is outstanding with a world's record 1 x 105 kW h of 28-GHz energy delivered to the EBT-S device with well over 1 x 103 operating hours

  5. Effects of coolant temperature and pump power on the power output of solar-pumped solid state lasers

    Thompson, George A.; Yogev, Amnon; Reich, A.; Oron, Moshe

    1992-11-01

    The temperature dependence of solar-pumped solid state lasers of Nd:YAG and two types of Nd:Cr:GSGG was studied over the temperature range of +30 to -60 C in a quasi-CW mode. All lasers had higher output powers at -40 C. The Nd:Cr:GSGG laser with a chromium concentration of 2.5 at. pct produced 70 W of power at -40 C, quasi-CW. If extrapolated to true CW operation this is equivalent to 350 W. The temperature dependence of the laser performance is attributed to changes in both the stimulated emission cross section and the resonator configuration.

  6. High power fiber lasers

    LOU Qi-hong; ZHOU Jun

    2007-01-01

    In this review article, the development of the double cladding optical fiber for high power fiber lasers is reviewed. The main technology for high power fiber lasers, including laser diode beam shaping, fiber laser pumping techniques, and amplification systems, are discussed in de-tail. 1050 W CW output and 133 W pulsed output are ob-tained in Shanghai Institute of Optics and Fine Mechanics, China. Finally, the applications of fiber lasers in industry are also reviewed.

  7. High-gradient High-charge CW Superconducting RF gun with CsK2Sb photocathode

    Pinayev, Igor; Tuozzolo, Joseph; Brutus, Jean Clifford; Belomestnykh, Sergey; Boulware, Chase; Folz, Charles; Gassner, David; Grimm, Terry; Hao, Yue; Jamilkowski, James; Jing, Yichao; Kayran, Dmitry; Mahler, George; Mapes, Michael; Miller, Toby; Narayan, Geetha; Sheehy, Brian; Rao, Triveni; Skaritka, John; Smith, Kevin; Snydstrup, Louis; Than, Yatming; Wang, Erdong; Wang, Gang; Xiao, Binping; Xin, Tianmu; Zaltsman, Alexander; Altinbas, Z; Ben-Zvi, Ilan; Curcio, Anthony; Di Lieto, Anthony; Meng, Wuzheng; Minty, Michiko; Orfin, Paul; Reich, Jonathan; Roser, Thomas; Smart, Loralie A; Soria, Victor; Theisen, Charles; Xu, Wencan; Wu, Yuan H; Zhao, Zhi

    2015-01-01

    High-gradient CW photo-injectors operating at high accelerating gradients promise to revolutionize many sciences and applications. They can establish the basis for super-bright monochromatic X-ray free-electron lasers, super-bright hadron beams, nuclear- waste transmutation or a new generation of microchip production. In this letter we report on our operation of a superconducting RF electron gun with a record-high accelerating gradient at the CsK2Sb photocathode (i.e. ~ 20 MV/m) generating a record-high bunch charge (i.e., 3 nC). We briefly describe the system and then detail our experimental results. This achievement opens new era in generating high-power electron beams with a very high brightness.

  8. Fast Fourier Transform Analysis of Welding Penetration Depth Using 2 kW CW Nd:YAG Laser Welding Machine

    We report experimental results on the correlations between welding penetration depth and the frequencies of the radiation from the welding pool. Various welding samples such as SUS304, brass, SUS316, etc. have been investigated with 2 kW CW Nd:YAG laser welding machine. The radiation signals from the plume generated by the interactions between the welding sample and laser with respect to the defocusing length was measured with fiber system collecting the plume signal. Analysis of the frequencies by using fast Fourier transform (FFT) shows that the penetration depth is deep as plume signal frequencies are low, shallow penetration depth for high frequencies. Frequencies up to 250 Hz for obtained signals can be analyzed with the discrete FFT. This is the useful method fur closed loop control of the laser power with respect to the welding penetration depth and is used for real time inspection of the welding quality

  9. Relaxation of residual stresses in 20%SiCw/6061Al composite as-extruded at high temperature

    2001-01-01

    The residual stress in a 20%SiCw/6061Al composite as-extruded was investigated by using X-ray stress measurement method. It was found that, high residual stress existed in the composite and residual stress distribution in each direction are not uniform. Relaxation process of residual stress in the composite was dynamically measured during annealing at high temperature. It is verified that the relaxation of residual stress obeys the power law at high temperature. With the creep mechanism, the relaxation behavior of residual stresses at high temperature was analyzed. The results show that, the stress exponent and activation energy for stress relaxation of the composite are obviously higher than those of the matrix alloy.

  10. Analytical investigation of thermal stress in enamel and dentin under CW and pulse Er:YAG solid-state laser

    Elahi, Parviz; Ebrahimi, Marjan

    2014-02-01

    The aim of this work is to evaluate thermal stress of Er:YAG laser radiation on enamel and dentin of the dental. The transient state heat conduction equation for pulse wave laser regime with energy of 100 mJ, 300 mJ and steady state heat conduction equation for CW regime with powers of 1 W, 5 W was solved analytically. Then, the thermally induced stress was investigated following the calculation of the temperature distribution. Using the thermo-mechanical characteristics of the dentin and the enamel, all components of stress were obtained. The thermal stress of Er:YAG laser radiation on the enamel and the dentin calculated in this work may be useful for clinical applications.

  11. Numerical simulation of end-pumped CW Nd3+: GdVO4 laser at 1063 nm

    Zu Ning-Ning; Sun Gui-Juan; Dai Zhen-Wen

    2008-01-01

    A theoretical model to simulate an end-pumped CW Nda+:GdVO4 laser at 1063nm is presented.Its essence is to use the propagation equations to demonstrate the spatial evolutions of the pump and the laser powers in the cavity,hence it is applicable to both low and high gain lasers.The simulation results obtained by this model are in good agreement with the experimental observations reported in the literature for a Ti:sapphire-pumped Nd3+:GdVO4 laser.Moreover,some parameters,such as the reflectivity of output coupler,the spot size of laser beam and the crystal length,are discussed with a view to optimizing the laser performance.

  12. The Rhodotron, a new 10 MeV, 100 kW, cw metric wave electron accelerator

    New applications for high energy, high current electron beam processing are continually expanding. Today, however, 10 MeV rf electron linacs are frequently limited to an average beam power of only 20 or 30 kW. To achieve higher beam power, CW operation and the use of lower frequencies are necessary. In the last years, the principle for a new kind of electron accelerator was developed by the Atomic Energy Agency (CEA) in France. This accelerator is based on the principle of recirculating a beam throughout a single coaxial cavity resonating in metric waves. A 3.3 MeV, 4 mA prototype has been built and successfully tested. The industrial accelerator developed by IBA in collaboration with the CEA is a 10 MeV, 100 kW beam power unit with an additional beam exit at 5 MeV. The cavity, made of copper-plated steel, will resonate at 107.5 MHz. A rf power of 100 kW is needed to produce an electric field allowing an energy gain of 1 MeV per crossing. In addition, 100 kW of power is needed for acceleration. The 200 kW output amplifier uses a 100 kW plate dissipation tetrode (TH 681 from Thomson-CSF) in a grounded grid configuration. In this paper, the design of the new model as well as the prototype manufacturing schedule are presented in more detail. (orig.)

  13. Diode-pumped continuous-wave and femtosecond Cr:LiCAF lasers with high average power in the near infrared, visible and near ultraviolet

    Demirbas, Umit; Baali, Ilyes; Acar, Durmus Alp Emre; Leitenstorfer, Alfred

    2015-01-01

    We demonstrate continuous-wave (cw), cw frequency-doubled, cw mode-locked and Q-switched mode-locked operation of multimode diode-pumped Cr:LiCAF lasers with record average powers. Up to 2.54 W of cw output is obtained around 805 nm at an absorbed pump power of 5.5 W. Using intracavity frequency doubling with a BBO crystal, 0.9 W are generated around 402 nm, corresponding to an optical-to-optical conversion efficiency of 12%. With an intracavity birefringent tuning plate, the fundamental and ...

  14. About possibilities of clearing near-Earth space from dangerous debris by a spaceborne laser system with an autonomous cw chemical HF laser

    The possibility of clearing hazardous near-Earth space debris using a spaceborne laser station with a large autonomous cw chemical HF laser is substantiated and the requirements to its characteristics (i.e., power and divergence of laser radiation, pulse duration in the repetitively pulsed regime, repetition rate and total time of laser action on space debris, necessary to remove them from the orbits of the protected spacecrafts) are determined. The possibility of launching the proposed spaceborne laser station to the orbit with the help of a 'Proton-M' carrier rocket is considered. (laser applications)

  15. Investigation on Mechanical Properties and Microstructure of Hydroxyapatite-SiCw Composite Bioceramics

    2005-01-01

    Hydroxyapatite-SiCw composite micropowder was synthesized using in-situ composite method,and hydroxyapatite-SiCw composite bioceramics with different content of SiCw were produced by hot pressing sintering method. The microstructures of the materials were analyzed by SEM, and the relative density, bending strength and fracture toughness of the materials were tested. The results show that the mechanical properties of composite material are best when the whisker content is 20-23.7% . The mechanical properties of the material are the best when the tensile stress acted on the composite material is parallel with the hot pressing plane, and they are the worst when the tensile stress acted on the composite material is normal to the hot pressing plane.

  16. Explosive boiling of Ge35Sb10S55 glass induced by a CW laser

    Graphical abstract: - Highlights: • Interaction of the CW 785 nm laser with chalcogenide GeSbS glass. • First demonstration of the explosive boiling induced by CW laser in glass. • Different processes as photo-induced oxidation, expansion, and viscosity-flow observed. • Applied diagnostics SEM, DHM, AFM, force spectroscopy, and micro-Raman spectroscopy. • Damage threshold determined at 1.2 × 1024s−1 cm−3 of absorbed photons. - Abstract: The response of bulk Ge35Sb10S55 glass to illumination by a continuous wave (CW) laser, sub-band-gap photons, was studied specifically with an atomic force microscopy including a force spectroscopy, with a digital holographic microscopy and with a scanning electron microscopy. Depending on the number of photons absorbed, photo-expansion, photo-oxidation and explosive boiling were observed

  17. First operation of the 850 MeV c.w. electron accelerator 'MAMI'

    At Mainz University a c.w. electron accelerator with output energy close to 1 GeV was demanded to allow coincidence experiments with electrons and photons in nuclear and medium energy physics. A maximum beam intensity of about 100 μA was considered to be ample for the experimental program envisaged. For the sake of ruggedness and reliability and to allow in-house manufacture it was decided to avoid the use of superconducting structure. Following these lines the concept of a cascade of three race track microtrons ('RTM') using normal conducting structure in c.w. operation was developed. The three stage normal conducting c.w. race track microtron 'MAMI' (MAinz MIcrotron) of Mainz University has recently been operated for the first time at full energy. The parameters of the machine are briefly communicated. A preliminary report on its performance is given

  18. 3.8 W of cw blue light generated by intracavity frequency doubling of a 946-nm Nd:YAG laser with LBO

    Chen, Y.; Peng, H.; Hou, W.; Peng, Q.; Geng, A.; Guo, L.; Cui, D.; Xu, Z.

    2006-05-01

    Efficient cw intracavity frequency doubling of a diode-end-pumped Nd:YAG laser operating on 4 F 3/2→4 I 9/2 transitions at 946 nm has been demonstrated. A symmetrical cavity with two composite laser rods was designed, which divides the pump power between the two composite laser rods, allowing for greater power scalability. A 30-mm-long LiB3O5 (LBO) crystal, cut for critical type I phase matching at 57 °C, was used for the intracavity frequency doubling of the laser. A maximum output power of 3.8 W in the blue spectral range at 473 nm has been achieved at 39 W of pump power. The beam quality M2 value is 2.3 in both horizontal and vertical dimensions.

  19. A 200 W diode-side-pumped CW 2 μm Tm:YAG laser with water cooling at 8°C

    Cao, D.; Peng, Q.; Du, S.; Xu, J.; Guo, Y.; Yang, J.; Bo, Y.; Zhang, J.; Cui, D.; Xu, Z.

    2011-04-01

    A water-cooled 785 nm diode-side-pumped high-power CW Tm:YAG laser system at 2 μm is reported. 200 W output power is achieved with cooling water running at 8°C. As far as we know, this is the highest output power for a diode-pumped all solid-state 2 μm Tm:YAG laser. The output corresponds to optical-to-optical conversion efficiency of 11.2%, with a slope efficiency of about 22.8%. To make the system structure simple, only deionized water is used as the coolant instead of alcohol- or glycol-water mixture or the liquid nitrogen in the reported high-power Tm rod laser experiments, which were performed at low temperature near the freezing point of water, or even below.

  20. nLight Demonstrates World Record Output Power at 1470nm

    2005-01-01

    Diode Laser Bar Outputs 88W CW in Eyesafe Wavelength Range nLight, a leading manufacturer of high-power semiconductor lasers, today announced that it has achieved a new world record for output power from a single 1-cm InP diode laser bar. The 50 percent fill factor bar produced 88W continuous-wave (CW) power at1470 nm. The bar was mounted on the company's commercially available CascadesTM microchannel water-cooled package.

  1. Intracavity frequency doubling of CW Ti:Sapphire laser utilising BiBO nonlinear crystal

    Thorhauge, Morten; Mortensen, Jesper Liltorp; Tidemand-Lichtenberg, Peter;

    Utilising BiBO nonlinear crystal frequency doubling a Ti:Sapphire CW laser gave 100 mW at 405 nm and 53 mW at 392 nm. Stability proved excellent without servo control. Broad tunability was shown around 392 nm.......Utilising BiBO nonlinear crystal frequency doubling a Ti:Sapphire CW laser gave 100 mW at 405 nm and 53 mW at 392 nm. Stability proved excellent without servo control. Broad tunability was shown around 392 nm....

  2. Ultrahigh-resolution Cn2 profiles derived from an FM-CW radar

    Jordan, Jim R.; McLaughlin, Scott

    1992-08-01

    The U.S. Army Atmospheric Science Laboratory operates a frequency modulated-continuous wave (FM-CW) radar at White Sands Missile Range, New Mexico. This 10 cm wavelength radar has the unique capability of measuring 2 m resolution Cn2 profiles to 2 km above ground level. At this short wavelength, scattering from point targets, presumably insects, seriously contaminates the turbulence measurements. The ability of the FM-CW radar to resolve individual insects even at two km allows the insect signature to be removed from the turbulent backscatter. Radar calibration, data, and a technique for removing insect contamination are presented.

  3. EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Characteristics of the evolution of a plasma formed by cw and pulse-periodic CO2 laser radiation in various gases

    Kanevskiĭ, M. F.; Stepanova, M. A.

    1990-06-01

    An investigation was made of the interaction between high-power cw and pulse-periodic CO2 laser radiation and a low-threshold optical breakdown plasma near a metal surface. Characteristics of the breakdown plasma were studied as a function of the experimental conditions. A qualitative analysis was made of the results using a simple one-dimensional model for laser combustion waves.

  4. Red-light-emitting laser diodes operating CW at room temperature

    Kressel, H.; Hawrylo, F. Z.

    1976-01-01

    Heterojunction laser diodes of AlGaAs have been prepared with threshold current densities substantially below those previously achieved at room temperature in the 7200-8000-A spectral range. These devices operate continuously with simple oxide-isolated stripe contacts to 7400 A, which extends CW operation into the visible (red) portion of the spectrum.

  5. Independent tunability of the double-mode-locked cw dye laser.

    Bourkoff, E

    1979-06-01

    We report a new configuration that enables the double-mode-locked cw dye laser to be independently tunable. In addition, the output coupling at each of the two wavelengths can be independently specified. A series of oscillographs shows some interesting features unique to double mode locking and also shows the effects of varying the two cavity lengths with respect to each other.

  6. Induction of the 'in vivo' chlorophyll fluorescence excited by CW and pulse-periodical laser radiation

    Inductional changes of fluorescence of the native chlorophyll molecules in plant leaves excited by CW and pulse-periodical laser radiation are studied. The opportunity of controlling of the photosynthesis efficiency through fluorescence response at different rates of the electron flow in charge transfer chain of the photosynthetic apparatus of plant is shown. (author). 13 refs.; 4 refs

  7. Use of Self-Management with the CW-FIT Group Contingency Program

    Kamps, Debra; Conklin, Carl; Wills, Howard

    2015-01-01

    The purpose of the study was to determine the effects of self-management as a tier two enhancement to the group contingency intervention, Class-Wide Function-related Intervention Teams Program (CW-FIT). Two classrooms, first and fourth grade, and two students in each of the classrooms participated in the intervention. The group contingency…

  8. Study of plasma formation in CW CO2 laser beam-metal surface interaction

    Azharonok, V. V.; Vasilchenko, Zh V.; Golubev, Vladimir S.; Gresev, A. N.; Zabelin, Alexandre M.; Chubrik, N. I.; Shimanovich, V. D.

    1994-04-01

    An interaction of the cw CO2 laser beam and a moving metal surface has been studied. The pulsed and thermodynamical parameters of the surface plasma were investigated by optical and spectroscopical methods. The subsonic radiation wave propagation in the erosion plasma torch has been studied.

  9. Applications of FM-CW laser radar to antenna contour mapping

    Slotwinski, A. R.

    1989-07-01

    The FM-CW coherent laser radar concept, based on the FM radar principle which makes use of the coherence and lunability of injection laser diodes, is discussed. Laser radar precision/time tradeoffs, block diagrams, system performance, fiber optic system implantation, and receiver improvements are briefly described.

  10. Measured signal amplitude distributions for a coherent FM-cw CO2 laser radar.

    Letalick, D; Renhorn, I; Steinvall, O

    1986-11-01

    Measurements of signal amplitude distributions with a FM-cw CO2 laser radar have been made against various targets in both imaging and staring modes. Data show good agreement with theoretical distributions. From the measurements conclusions are drawn about the atmospheric- as well as target-induced effects. Beam wandering effects are shown to be of importance in the staring mode. PMID:18235723

  11. Klystron power supply for KOMAC

    A switching mode power supply (SMPS) is a hopeful candidate for the 1 MW CW klystron power supply of KOMAC (KOrea Multi-purpose Accelerator Complex). The merits of the SMPS are low stored energy, small size, high rating efficiency and possible cost saving whereas the demerits are EMI problem and system complexities. The proposed power is 2 MW and it is considered that the modules, each of which has the power of 200 kW, are connected in series to supply the total power. As a first step, a 200 kW SMPS is studied and designed. An overview of the power supply designed so far is presented. (author)

  12. Antiviral Potential of a Novel Compound CW-33 against Enterovirus A71 via Inhibition of Viral 2A Protease.

    Wang, Ching-Ying; Huang, An-Cheng; Hour, Mann-Jen; Huang, Su-Hua; Kung, Szu-Hao; Chen, Chao-Hsien; Chen, I-Chieh; Chang, Yuan-Shiun; Lien, Jin-Cherng; Lin, Cheng-Wen

    2015-06-01

    Enterovirus A71 (EV-A71) in the Picornaviridae family causes hand-foot-and-mouth disease, aseptic meningitis, severe central nervous system disease, even death. EV-A71 2A protease cleaves Type I interferon (IFN)-α/β receptor 1 (IFNAR1) to block IFN-induced Jak/STAT signaling. This study investigated anti-EV-A7l activity and synergistic mechanism(s) of a novel furoquinoline alkaloid compound CW-33 alone and in combination with IFN-β Anti-EV-A71 activities of CW-33 alone and in combination with IFN-β were evaluated by inhibitory assays of virus-induced apoptosis, plaque formation, and virus yield. CW-33 showed antiviral activities with an IC50 of near 200 µM in EV-A71 plaque reduction and virus yield inhibition assays. While, anti-EV-A71 activities of CW-33 combined with 100 U/mL IFN-β exhibited a synergistic potency with an IC50 of approximate 1 µM in plaque reduction and virus yield inhibition assays. Molecular docking revealed CW-33 binding to EV-A71 2A protease active sites, correlating with an inhibitory effect of CW33 on in vitro enzymatic activity of recombinant 2A protease IC50 = 53.1 µM). Western blotting demonstrated CW-33 specifically inhibiting 2A protease-mediated cleavage of IFNAR1. CW-33 also recovered Type I IFN-induced Tyk2 and STAT1 phosphorylation as well as 2\\',5\\'-OAS upregulation in EV-A71 infected cells. The results demonstrated CW-33 inhibiting viral 2A protease activity to reduce Type I IFN antagonism of EV-A71. Therefore, CW-33 combined with a low-dose of Type I IFN could be applied in developing alternative approaches to treat EV-A71 infection. PMID:26090728

  13. Antiviral Potential of a Novel Compound CW-33 against Enterovirus A71 via Inhibition of Viral 2A Protease

    Ching-Ying Wang

    2015-06-01

    Full Text Available Enterovirus A71 (EV-A71 in the Picornaviridae family causes hand-foot-and-mouth disease, aseptic meningitis, severe central nervous system disease, even death. EV-A71 2A protease cleaves Type I interferon (IFN-α/β receptor 1 (IFNAR1 to block IFN-induced Jak/STAT signaling. This study investigated anti-EV-A7l activity and synergistic mechanism(s of a novel furoquinoline alkaloid compound CW-33 alone and in combination with IFN-β Anti-EV-A71 activities of CW-33 alone and in combination with IFN-β were evaluated by inhibitory assays of virus-induced apoptosis, plaque formation, and virus yield. CW-33 showed antiviral activities with an IC50 of near 200 µM in EV-A71 plaque reduction and virus yield inhibition assays. While, anti-EV-A71 activities of CW-33 combined with 100 U/mL IFN-β exhibited a synergistic potency with an IC50 of approximate 1 µM in plaque reduction and virus yield inhibition assays. Molecular docking revealed CW-33 binding to EV-A71 2A protease active sites, correlating with an inhibitory effect of CW33 on in vitro enzymatic activity of recombinant 2A protease IC50 = 53.1 µM. Western blotting demonstrated CW-33 specifically inhibiting 2A protease-mediated cleavage of IFNAR1. CW-33 also recovered Type I IFN-induced Tyk2 and STAT1 phosphorylation as well as 2',5'-OAS upregulation in EV-A71 infected cells. The results demonstrated CW-33 inhibiting viral 2A protease activity to reduce Type I IFN antagonism of EV-A71. Therefore, CW-33 combined with a low-dose of Type I IFN could be applied in developing alternative approaches to treat EV-A71 infection.

  14. High CW power, phase and amplitude modulatorrealized with fast ferrite phase-shifters

    Valuch, D

    2004-01-01

    Superconducting cavity resonators are suffering from detuning effects caused by high internal electromagnetic fields (Lorentz force detuning). For classical resonators working with continuous wave signals, this detuning is static and compensated by the slow mechanical tuning system. However, pulsing of superconducting cavities, an operational mode only recently considered, results in dynamic detuning effects. New ways to handle this effect have to be found and worked out. A way to supply several superconducting cavities in the particle accelerator by one large transmitter while keeping the possibility of controlling the field in each individual cavity is shown. By introducing a fast phase and amplitude modulator into each cavity feeder line, the individual deviations of each cavity with respect to the average can be compensated in order to equalize their behaviour for the main control loop, which will compensate the global detuning of all cavities. Several types of phase and amplitude modulators suitable for ...

  15. Beam dynamics simulation of injector for high power CW electron linac in PNC

    The injector consists of a 200 kV DC gun, a RF chopper, a chopper slit, a prebuncher and a buncher. Solenoid coils covered from the exit of gun to accelerating tube 1 except between the RF chopper and chopper slit. Beam trajectories are simulated by PARMELA in order to design the injector. In this report, two simulation results are shown. One is for a beam trajectory from gun to solenoid coils. There is thick concrete wall between gun to RF chopper. Low energy electrons are transported through long solenoid coil area. The other is for a chopper part. The novel chopper system is designed to reduce the emittance growth. (author)

  16. Further Characterization of 394-GHz Gyrotron FU CW GII with Additional PID Control System for 600-MHz DNP-SSNMR Spectroscopy

    Ueda, Keisuke; Matsuki, Yoh; Fujiwara, Toshimichi; Tatematsu, Yoshinori; Ogawa, Isamu; Idehara, Toshitaka

    2016-09-01

    A 394-GHz gyrotron, FU CW GII, has been designed at the University of Fukui, Japan, for dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR) experiments at 600-MHz 1H resonant frequency. After installation at the Institute for Protein Research (IPR), Osaka University, Japan, a PID feedback control system was equipped to regulate the electron gun heater current for stabilization of the electron beam current, which ultimately achieved stabilization of output power when operating in continuous wave (CW) mode. During exploration to further optimize operating conditions, a continuous tuning bandwidth of approximately 1 GHz was observed by varying the operating voltage at a fixed magnetic field. In the frequency range required for positive DNP enhancement, the output power was improved by increasing the magnetic field and the operating voltage from their initial operational settings. In addition, fine tuning of output frequency by varying the cavity cooling water temperature was demonstrated. These operating conditions and ancillary enhancements are expected to contribute to further enhancement of SSNMR signal.

  17. Further Characterization of 394-GHz Gyrotron FU CW GII with Additional PID Control System for 600-MHz DNP-SSNMR Spectroscopy

    Ueda, Keisuke; Matsuki, Yoh; Fujiwara, Toshimichi; Tatematsu, Yoshinori; Ogawa, Isamu; Idehara, Toshitaka

    2016-04-01

    A 394-GHz gyrotron, FU CW GII, has been designed at the University of Fukui, Japan, for dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR) experiments at 600-MHz 1H resonant frequency. After installation at the Institute for Protein Research (IPR), Osaka University, Japan, a PID feedback control system was equipped to regulate the electron gun heater current for stabilization of the electron beam current, which ultimately achieved stabilization of output power when operating in continuous wave (CW) mode. During exploration to further optimize operating conditions, a continuous tuning bandwidth of approximately 1 GHz was observed by varying the operating voltage at a fixed magnetic field. In the frequency range required for positive DNP enhancement, the output power was improved by increasing the magnetic field and the operating voltage from their initial operational settings. In addition, fine tuning of output frequency by varying the cavity cooling water temperature was demonstrated. These operating conditions and ancillary enhancements are expected to contribute to further enhancement of SSNMR signal.

  18. CW Yb:YAG LASER FOR PORTABLE MEASURING SYSTEMS

    A. M. Ivashko; Kisel, V.E.; A. S. Yasukevich; N. V. Kuleshov

    2015-01-01

    The theoretical and experimental results of longitudinally continuous-wave diode-pumped Yb:Y3Al5O12 (YAG) laser performance for compact field-condition measuring systems were demonstrated. Optimization of laser setup in terms of operation condition in the range of -40 ˚С – +65 ˚С without active thermal stabilization was carried out. Using Yb (10 ат.%):YAG crystal with the length of 3 mm the maximal output power more than 2 W was obtained in the whole of temperature range.

  19. 303.5 nm cw Pr:BYF–BBO laser emission under 447 nm all-solid-state Nd:GdVO4–BiBO blue laser pumping

    An all-solid-state blue laser-pumped Pr:BaY2F5 (Pr:BYF) laser at 607 nm has been demonstrated. With an incident 447 nm pump power of 1.04 W, the maximum orange output power was 337 mW. Moreover, intracavity second-harmonic generation (SHG) has also been achieved with a maximum UV power of 76 mW by using a β-BaB2O4 (BBO) nonlinear crystal. To the best of our knowledge, this is the first report on continuous-wave (cw) UV generation by an intracavity frequency doubling Pr:BYF laser. (letter)

  20. 303.5 nm cw Pr:BYF-BBO laser emission under 447 nm all-solid-state Nd:GdVO4-BiBO blue laser pumping

    Chen, X.; Shao, Y.; Yuan, J. L.; Zhang, D.; Wang, A. G.

    2013-06-01

    An all-solid-state blue laser-pumped Pr:BaY2F5 (Pr:BYF) laser at 607 nm has been demonstrated. With an incident 447 nm pump power of 1.04 W, the maximum orange output power was 337 mW. Moreover, intracavity second-harmonic generation (SHG) has also been achieved with a maximum UV power of 76 mW by using a β-BaB2O4 (BBO) nonlinear crystal. To the best of our knowledge, this is the first report on continuous-wave (cw) UV generation by an intracavity frequency doubling Pr:BYF laser.

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

    Rees, D; 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. Tube operation was still possible and the klystron operated up to 70% of full beam power with excellent vacuum. The indication that finally led us to the collector failure was variable emission. This information will be discussed. A hydrophonic system was implemented to diagnose collector heating. The collectors are designed to allow for mixed-phase cooling and with the hydrophonic test equipment we are able to observe: normal, single-phase cooling, mixed-phase cooling, and a hard boil. These data will be presented. The...

  2. Carbonated water (CW) process waste reuse for ammonium-uranyl-carbonate (AUC) production and its gains on the environmental, economic and social aspects

    In the INB nuclear fuel cycle, the pellets production is based on UO2 powder made by AUC (Ammonium-Uranyl-Carbonate) route. AUC formation occurs by fluidising of UF6, NH3 and CO2 in a vase containing usually pure water, and this exothermal reaction has AUC as direct product. The mass formed is filtered, washed with CW, washed again with methano solution, dried with air and conducted to the fluidized bed furnace, to be converted to UO2 powder. At this point, the dried AUC decompounds to UO3, NH3 and C02, these 2 gases are absorbed at the gases washer, formin go the carbonated water (CW), whit is basically a (NH4)2CO3 solution. The UO2+x is reduced and stabilized to UO2 powder, which is conducted to pellets production. During the process, a considerable amount of this aqueous waste is generated and goes for effluent treatment. After that, the solution is sent for spray-dryer for power formation, and stock. This treatment demands equipment, energy and time, representing considerable costs of the company beyond the human risks involved on the drying step. The purpose of this work is to present a study of the carbonated water use as substitute of pure water in the AUC formation step. At this point, tests were made varying the CW loads for the AUC precipitation, and the control was made by the UO2 powder properties. The carbonated water used for AUC precipitation has been tested at several levels and the results has demonstrated full viability to become a definitive process step (INB, Resende site). It has been demonstrated the great resources economy caused by the waste reuse and the guarantee product quality. This represents such an environmental gain and also economic and social aspects got improved. (author)

  3. CW high intensity non-scaling FFAG proton drivers

    Johnstone, C; Makino, K; Snopok, P

    2012-01-01

    Accelerators are playing increasingly important roles in basic science, technology, and medicine including nuclear power, industrial irradiation, material science, and neutrino production. Proton and light-ion accelerators in particular have many research, energy and medical applications, providing one of the most effective treatments for many types of cancer. Ultra high-intensity and high-energy (GeV) proton drivers are a critical technology for accelerator-driven sub-critical reactors (ADS) and many HEP programs (Muon Collider). These high-intensity GeV-range proton drivers are particularly challenging, encountering duty cycle and space-charge limits in the synchrotron and machine size concerns in the weaker-focusing cyclotrons; a 10-20 MW proton driver is not presently considered technically achievable with conventional re-circulating accelerators. One, as-yet, unexplored re-circulating accelerator, the Fixed-field Alternating Gradient, or FFAG, is an attractive alternative to the cyclotron. Its strong foc...

  4. Development of 20 kW input power coupler for 1.3 GH ERL main linac. High power test of the renewed ceramic window

    We started to develop an input power coupler for a 1.3 GHz ERL superconducting cavity for main linac. We fabricated power coupler components such as ceramic windows and bellows and carried out the high-power test of the components by using a CW 30 kW IOT power source. During this test, the ceramic window was broken by the sudden heat load. We found that this heat load occurred by the unexpected dipole mode. We renewed the ceramic window and successfully carried out the high power test up to CW 27 kW input power. (author)

  5. Relationship of HLA-A, -Cw Polymorphisms with HIV/AIDS in Chinese Yi Ethnic Group of Sichuan Province

    2007-01-01

    The relationship of HLA-A, -Cw alleles on HIV infection and AIDS disease progression in the Chinese Yi ethnic group of Sichuan province were investigated. The genetic polymorphisms of HLA-A, -Cw alleles of 102 unrelated healthy Chinese Yi ethnic individuals, 68 HIV-1 infected and 21 HIV positive long-time survivors were typed by PCR-SSP assay. Statistic signifiance was determined by the χ2 test with the SPSS software. No significant differences were observed between the HLA-A, -Cw alleles of the 68 HIV-1 infected and 102 non-infected Chinese Yi control individuals. Whereas the prevalence of A*3601,Cw*14(01-03)and Cw*0304 was significantly higher in 21 long time survivors compared with 102 healthy controls with P values of 0.016, 0.016 and 0.000 by χ2 or the Fisher exact test respectively. The result implies that A*3601,Cw*14(01-03) and Cw*0304 may be associated with slow AIDS disease progression in the Chinese Yi ethnic group, further studies on this association may yield insight on the pathogenesis of HIV-1 infection.

  6. CW Measurement of the Upward-Going Temperature Wave in the Helium-4 Self-Organized Critical State

    We describe the first continuous-wave (CW) measurements of the upward-going temperature wave in the self-organized-critical (SOC) state which forms in 4He under conditions of downward heat flow near Tλ under gravity. The CW technique permits measurements with extremely low (<1 nK) excitation amplitudes, allows continuous measurement of the wave velocity as the SOC state grows, and has yielded the first quantitative measurements of the attenuation. The CW measurements appear to support predictions for the velocity but disagree with predictions for the attenuation. This new technique may help us understand the underlying mechanism of the SOC state

  7. CW/Pulsed H{sup −} ion beam generation with PKU Cs-free 2.45 GHz microwave driven ion source

    Peng, S. X., E-mail: sxpeng@pku.edu.cn; Ren, H. T.; Xu, Y.; Zhang, T.; Zhang, J. F.; Zhao, J.; Guo, Z. Y. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, People' s Republic of China (China); Zhang, A. L. [University of Chinese Academy of Sciences, Beijing 100049, People' s Republic of China (China); Chen, J. E. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, People' s Republic of China (China); University of Chinese Academy of Sciences, Beijing 100049, People' s Republic of China (China)

    2015-04-08

    Circular accelerators used for positron emission tomography (PET, i.e. accelerator used for make radio isotopes) need several mA of CW H- ion beam for their routine operation. Other facilities, like Space Radio-Environment Simulate Assembly (SPRESA), require less than 10 mA pulsed mode H{sup −} beam. Caesium free negative hydrogen ion source is a good choice for those facilities because of its compact structure, easy operation and low cost. Up to now, there is no H{sup −} source able to produce very intense H{sup −} beams with important variation of the duty factor{sup [1]}. Recently, a new version of 2.45 GHz microwave H{sup −} ion source was designed at PKU, based on lessons learnt from the previous one. This non cesiated source is very compact thanks to its permanent magnet configuration. Special attention was paid on the design of the discharge chamber structure, electron dumping and extraction system. Source test to produce H{sup −} ion beams in pulsed and CW mode was carried out on PKU ion source test bench. In CW mode, a 10.8 mA/30keV H{sup −} beam with rms emittance about 0.16 π·mm·mrad has been obtained with only 500 W rf power. The power efficiency reaches 21 mA/kW. In pulsed mode with duty factor of 10% (100Hz/1ms), this compact source can easily deliver 20 mA H{sup −} ion beam at 35 keV with rms emittance about 0.2 π·mm·mrad when RF power is set at 2.2 kW (peak power). Several hour successive running operation in both modes and totaling more than 200 hours proves its high quality. The outside dimension of this new H{sup −} source body is ϕ116 mm × 124 mm, and the entire H{sup −} source infrastructure, including rf matching section, plasma chamber and extraction system, is ϕ310 × 180 mm. The high voltage region is limited with in a ϕ310 mm × 230 mm diagram. Details are given in this paper.

  8. Choosing dyes for cw-STED nanoscopy using self-assembled nanorulers.

    Beater, Susanne; Holzmeister, Phil; Pibiri, Enrico; Lalkens, Birka; Tinnefeld, Philip

    2014-04-21

    Superresolution microscopy is currently revolutionizing optical imaging. A key factor for getting images of highest quality is - besides a well-performing imaging system - the labeling of the sample. We compared the fluorescent dyes Abberior Star 488, Alexa 488, Chromeo 488 and Oregon Green 488 for use in continuous wave (cw-)STED microscopy in aqueous buffer and in a durable polymer matrix. To optimize comparability, we designed DNA origami standards labeled with the fluorescent dyes including a bead-like DNA origami with dyes focused on one spot and a DNA origami with two marks at a designed distance of ∼100 nm. Our data show that all dyes are well suited for cw-STED microscopy but that the optimal dye depends on the embedding medium. The precise comparison enabled by DNA origami nanorulers indicates that these structures have matured from the proof-of-concept to easily applicable tools in fluorescence microscopy. PMID:24599511

  9. Multilayer optical data storage by fluorescence modulation using a CW laser

    Singer, Kenneth D.; Christenson, Cory W.; Saini, Anuj; Ryan, Christopher J.; Mirletz, Heather; Shiyanovskaya, Irina; Yin, Kezhen; Baer, Eric

    2015-08-01

    Optical data storage has been widely used in certain consumer applications owing to its passive and robust nature, but has failed to keep with larger industry data storage needs due to the lack of capacity. Many alternatives have been proposed and developed, such as 3D data storage using two-photon absorption that require complex and dangerous laser systems to localize the bits. In this paper, we present a method for localizing bits using a CW 405nm laser diode, in a multilayered polymer film. Data is stored by photobleaching a fluorescent dye, and the response of the material is nonlinear, despite the CW laser and absorption in the visible region. This is achieved using sub-μs pulses from the laser initiating a photothermal effect. This writing method, along with the inexpensive roll-to-roll method for making the disc, will allow for terabyte-scale optical discs using conventional commercial optics and lasers.

  10. Rapid-swept CW cavity ring-down laser spectroscopy for carbon isotope analysis

    With the aim of developing a portable system for an in field isotope analysis, we investigate an isotope analysis based on rapid-swept CW cavity ring-down laser spectroscopy, in which the concentration of a chemical species is derived from its photo absorbance. Such a system can identify the isotopomer and still be constructed as a quite compact system. We have made some basic experimental measurements of the overtone absorption lines of carbon dioxide (12C16O2, 13C16O2) by rapid-swept cavity ring-down spectroscopy with a CW infrared diode laser at 6,200 cm-1 (1.6 μm). The isotopic ratio has been obtained as (1.07±0.13)x10-2, in good agreement with the natural abundance within experimental uncertainty. The detection sensitivity in absorbance has been estimated to be 3x10-8 cm-1. (author)

  11. CW Interference Effects on High Data Rate Transmission Through the ACTS Wideband Channel

    Kerczewski, Robert J.; Ngo, Duc H.; Tran, Quang K.; Tran, Diepchi T.; Yu, John; Kachmar, Brian A.; Svoboda, James S.

    1996-01-01

    Satellite communications channels are susceptible to various sources of interference. Wideband channels have a proportionally greater probability of receiving interference than narrowband channels. NASA's Advanced Communications Technology Satellite (ACTS) includes a 900 MHz bandwidth hardlimiting transponder which has provided an opportunity for the study of interference effects of wideband channels. A series of interference tests using two independent ACTS ground terminals measured the effects of continuous-wave (CW) uplink interference on the bit-error rate of a 220 Mbps digitally modulated carrier. These results indicate the susceptibility of high data rate transmissions to CW interference and are compared to results obtained with a laboratory hardware-based system simulation and a computer simulation.

  12. Synthetic aperture FM-CW radar applied to the detection of objects buried in snowpack

    Yamaguchi, Yoshio; Mitsumoto, Masashi; Sengoku, Masakazu; Abe, Takeo

    1994-01-01

    This paper presents the principle of synthetic aperture frequency modulated continuous wave (FM-CW) radar and demonstrates the detection results of several objects buried in natural snowpack using the radar system. First, the synthetic aperture technique is explained with emphasis placed on showing that the Fourier transformed beat signal obtained by the FM-CW radar is equivalent to one kind of Fresnel hologram, which leads us to use SAR technique. Then a radar system operative in the microwave L-band is explored to detect objects buried in natural snowpack. Several detection results are presented demonstrating the potential capability of high resolution imaging in the azimuth direction, comparing with real aperture images.

  13. First observational results with the newly developed cloud profiling FM-CW radar at 95 GHz

    Takano, Toshiaki; Suga, Yumiro; Akita, Kenichi; Kawamura, Youhei; Kumagai, Hiroshi; Takamura, Tamio; Nakanishi, Yuji; Nakajima, Teruyuki

    2004-02-01

    We developed a 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 high sensitivity to small cloud particles. An FM-CW type radar would realize similar sensitivity with much smaller output 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 15 km in height with a resolution of 15 m. Using the facility, test observations and long term campaign observations have been done. Results of observations show that the system is sensitive and stable enough to observe various clouds.

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

    Sheen, David M.

    2015-06-19

    Near field radar imaging systems are used for several applications including concealed weapon detection in airports and other high-security venues. Despite the near-field operation, phase noise and thermal noise can limit the performance in several ways including reduction in system sensitivity and reduction of image dynamic range. 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.

  15. A novel CW yellow light generated by a diode-end-pumped intra-cavity frequency mixed Nd:YVO4 laser

    Li, Bin; Yao, Jian Quan; Ding, Xin; Sheng, Quan; Yin, Sujia; Shi, Chunpeng; Li, Xue; Yu, Xuanyi; Sun, Bing

    2014-03-01

    We report an efficient continuous-wave (CW) yellow beam based on a Nd:YVO4 laser with a dual-wavelength wave plate, which is a full-wave plate at 1342 nm and a quarter-wave plate at 1064 nm. By inserting the dual-wavelength wave plate into the laser cavity and tuning the fast axis angle, based on the polarized property emission of Nd:YVO4, two simultaneous wavelengths of 1064 nm and 1342 nm were achieved. A LiB3O5 (LBO) crystal that is cut for critical type I phase matching at room temperature is used for summing frequency generation (SFG) of the laser. At an incident pump power of 5 W, a maximum CW output of 224 mW was obtained for a yellow laser with a wavelength of 593.5 nm and an optical-to-optical efficiency of 4.48%. To the best of our knowledge, this is the first time that a dual-wavelength wave plate has been used to realize a Nd:YVO4 yellow laser output.

  16. Room-temperature CW operation of a nitride-based vertical-cavity surface-emitting laser using thick GaInN quantum wells

    Furuta, Takashi; Matsui, Kenjo; Horikawa, Kosuke; Ikeyama, Kazuki; Kozuka, Yugo; Yoshida, Shotaro; Akagi, Takanobu; Takeuchi, Tetsuya; Kamiyama, Satoshi; Iwaya, Motoaki; Akasaki, Isamu

    2016-05-01

    We demonstrated a room-temperature (RT) continuous-wave (CW) operation of a GaN-based vertical-cavity surface-emitting laser (VCSEL) using a thick GaInN quantum well (QW) active region and an AlInN/GaN distributed Bragg reflector. We first investigated the following two characteristics of a 6 nm GaInN 5 QWs active region in light-emitting diode (LED) structures. The light output power at a high current density (∼10 kA/cm2) from the 6 nm GaInN 5 QWs was the same or even higher than that from standard 3 nm 5 QWs. In addition, we found that hole injection into the farthest QW from a p-layer was sufficient. We then demonstrated a GaN-based VCSEL with the 6 nm 5 QWs, resulting in the optical confinement factor of 3.5%. The threshold current density under CW operation at RT was 7.5 kA/cm2 with a narrow (0.4 nm) emission spectrum of 413.5 nm peak wavelength.

  17. VHR Image Specifications for the CwRS Programme Campaign 2009

    AASTRAND Paer; ERLANDSSON Maria

    2009-01-01

    This document constitutes the specifications for VHR imagery to be used within the CwRS Programme. Its objective is to give the stakeholders in the image acquisition management chain clarity in the technical details of the process and describes the process flow starting from zone definition, through the image use, reaching image return and possible re-use of imagery at end of Campaign

  18. Enhanced Type-I Polarization-Entangled Photons Using CW-Diode Laser

    Hegazi, Salem; Mansour, Mohy S.; El Nadi, Lotfia

    2013-03-01

    We used two type-I BBO crystals pumped by violet cw-diode laser of relatively wide bandwidth to produce entangled photons of considerable degree of purity. While diode laser serves the mobility and the low-cost of the entangled photons source, suitable temporal compensation is required in this case to recover the purity of the state. We studied also effect of tilting the two-crystal set on overlapping of the SPDC cones.

  19. Improving the Survival of Arthrobacter sp., CW9 during Spray Drying Monitored by Scan Electric Microscope

    Zhenqiang Xia; Ming Zhu; Yanqiu Zhang

    2014-01-01

    The culture of an aquaculture probiotic, i.e., Arthrobacter sp., CW9, was spray dried with different carriers/protectants, in which Scan Electric Microscope (SEM) was used to analyze the surface of micro-paticles produced by spray-drying. Matrix of protectants, inlet temperature and feed rate were optimized according to the survival rate after spray drying. Scanning electron micrographs showed that cracks formed on the particle surface were a key factor in enhancing bacteria survival during s...

  20. Real-time determination of Doppler and polarization parameters using an FM-CW radar

    Niemeijer, R. J.; van Sinttruyen, J. S.; Ligthart, L. P.

    The Delft Atmospheric Research Radar (DARR) is based on the FM-CW principle and operates at frequencies in the S-band. A description is given of the first measurement results obtained with DARR and its newly implemented real-time Doppler-polarimetry computer programs. Measurements of a flat rotating plate and a tower, with emphasis on the possibilities of polarimetric target suppression, are shown.

  1. Measurements of Partial Reflections at 3.18 Mhz Using the CW Radar Technique

    Priese, J.; Singer, W.

    1984-01-01

    An equipment for measuring partial reflections using the FM-CW-radar principle at 3.18 MHz, installed at the Ionospheric Observatory Juliusruh of the CISTP (HHI), is described. The linear FM-chirp of 325 kHz bandwidth is Gaussian-weighted in amplitude and gives a height resolution of 1.5 km (chirp length is 0.6 sec). Preliminary results are presented for the first observation period in winter 1982/83.

  2. Resonance Ionization Mass Spectrometry (RIMS) with Pulsed and CW-Lasers on Plutonium

    Kunz, P.; Huber, G.; Passler, G.; Trautmann, N.; Wendt, K.

    2005-04-01

    The detection of long-lived plutonium isotopes in ultra-trace amounts by resonance ionization mass spectrometry (RIMS) is a well-established routine method. Detection limits of 106 to 107 atoms and precise measurements of the isotopic composition have been achieved. In this work multi-step resonance ionization of plutonium atoms has been performed with tunable lasers having very different output intensities and spectral properties. In order to compare different ways for the resonance ionization of plutonium broadband pulsed dye and titanium:sapphire lasers as well as narrow-band cw-diode and titanium:sapphire lasers have been applied for a number of efficient excitation schemes. It has been shown, that for identical excitation schemes the optical isotope selectivity can be improved by using cw-lasers (bandwidths lasers (bandwidths > 2 GHz). Pulsed and cw-laser systems have been used simultaneously for resonance ionization enabling direct comparisons of pulsed and continuous ionization processes. So far, a three-step, three-color laser excitation scheme has been proven to be most practical in terms of efficiency, selectivity and laser wavelengths. Alternatively a newly discovered three-step, two-color excitation scheme which includes a strong two-photon transition from an excited state into a high-lying autoionizing state yields similar ionization efficiencies. This two-photon transition was characterized with respect to saturation behavior and line width.

  3. Resonance Ionization Mass Spectrometry (RIMS) with Pulsed and CW-Lasers on Plutonium

    The detection of long-lived plutonium isotopes in ultra-trace amounts by resonance ionization mass spectrometry (RIMS) is a well-established routine method. Detection limits of 106 to 107 atoms and precise measurements of the isotopic composition have been achieved. In this work multi-step resonance ionization of plutonium atoms has been performed with tunable lasers having very different output intensities and spectral properties. In order to compare different ways for the resonance ionization of plutonium broadband pulsed dye and titanium:sapphire lasers as well as narrow-band cw-diode and titanium:sapphire lasers have been applied for a number of efficient excitation schemes. It has been shown, that for identical excitation schemes the optical isotope selectivity can be improved by using cw-lasers (bandwidths 2 GHz). Pulsed and cw-laser systems have been used simultaneously for resonance ionization enabling direct comparisons of pulsed and continuous ionization processes. So far, a three-step, three-color laser excitation scheme has been proven to be most practical in terms of efficiency, selectivity and laser wavelengths. Alternatively a newly discovered three-step, two-color excitation scheme which includes a strong two-photon transition from an excited state into a high-lying autoionizing state yields similar ionization efficiencies. This two-photon transition was characterized with respect to saturation behavior and line width.

  4. Design of 57.5 MHz CW RFQ structure for the Rare Isotope Accelarator Facility

    P N Ostroumov; A A Kolomiets; D A Kashinsky; S A Minaev; V I Pershin; T E Tretyakova; S G Yaramishev

    2002-12-01

    The Rare Isotope Accelerator (RIA) facility includes a driver LINAC for production of 400 kW CW heavy-ion beams. The initial acceleration of heavy ions delivered from an ECR ion source can be effectively performed by a 57.5 MHz 4 m long RFQ. The principal specifications of the RFQ are: (1) formation of extremely low longitudinal emittance; (2) stable operation over a wide range of voltage for acceleration of various ion species needed for RIA operation; (3) simultaneous acceleration of two-charge states of uranium ions. CW operation of an accelerating structure leads to a number of requirements for the resonators such as high shunt impedance, efficient water cooling of all parts of the resonant cavity, mechanical stability together with precise alignment, reliable rf contacts, a stable operating mode and fine tuning of the resonant frequency during operation. To satisfy these requirements a new resonant structure has been developed. This paper discusses beam dynamics and electrodynamics design of the RFQ cavity, as well as, some aspects of the mechanical design of this low-frequency CW RFQ.

  5. Prospects for CW and LP operation of the European XFEL in hard X-ray regime

    Brinkmann, R; Sekutowicz, J; Yurkov, M V

    2014-01-01

    The European XFEL will operate nominally at 17.5 GeV in SP (short pulse) mode with 0.65 ms long bunch train and 10 Hz repetition rate. A possible upgrade of the linac to CW (continuous wave) or LP (long pulse) modes with a corresponding reduction of electron beam energy is under discussion since many years. Recent successes in the dedicated R&D program allow to forecast a technical feasibility of such an upgrade in the foreseeable future. One of the challenges is to provide sub-Angstrom FEL operation in CW and LP modes. In this paper we perform a preliminary analysis of a possible operation of the European XFEL in the hard X-ray regime in CW and LP modes with the energies of 7 GeV and 10 GeV, respectively. We consider lasing in the baseline XFEL undulator as well as in a new undulator with a reduced period. We show that, with reasonable requirements on electron beam quality, lasing on the fundamental will be possible in sub-Angstrom regime. As an option for generation of brilliant photon beams at short wa...

  6. Prospects for CW and LP operation of the European XFEL in hard X-ray regime

    Brinkmann, R.; Schneidmiller, E.A.; Sekutowicz, J.; Yurkov, M.V.

    2014-03-15

    The European XFEL will operate nominally at 17.5 GeV in SP (short pulse) mode with 0.65 ms long bunch train and 10 Hz repetition rate. A possible upgrade of the linac to CW (continuous wave) or LP (long pulse) modes with a corresponding reduction of electron beam energy is under discussion since many years. Recent successes in the dedicated R and D program allow to forecast a technical feasibility of such an upgrade in the foreseeable future. One of the challenges is to provide sub-Aangstrom FEL operation in CW and LP modes. In this paper we perform a preliminary analysis of a possible operation of the European XFEL in the hard X-ray regime in CW and LP modes with the energies of 7 GeV and 10 GeV, respectively. We consider lasing in the baseline XFEL undulator as well as in a new undulator with a reduced period. We show that, with reasonable requirements on electron beam quality, lasing on the fundamental will be possible in sub-Aangstrom regime. As an option for generation of brilliant photon beams at short wavelengths we also consider harmonic lasing that has recently attracted a significant attention.

  7. Analysis of relaxation times of radicals in irradiated black pepper using pulse-ESR and CW-ESR

    We attempted measurement of radicals in irradiated black pepper using pulse-ESR and CW-ESR. Relaxation times (T1, T2) of radicals in black pepper were measured using pulse-ESR. T1 and T2 were also calculated theoretical analysis using CW-ESR parameter. We succeeded in measurement of the field swept echo of irradiated black pepper using pulse-ESR. Pulse-ESR and CW-ESR were able to calculate T1 and T2. T1 values were showed no dose dependence. T2 values showed increase according to irradiation. We revealed that T1 and T2 from pulse-ESR and CW-ESR were changed similarly before and after irradiation. (author)

  8. RF power generation

    Carter, R G

    2011-01-01

    This paper reviews the main types of r.f. power amplifiers which are, or may be, used for particle accelerators. It covers solid-state devices, tetrodes, inductive output tubes, klystrons, magnetrons, and gyrotrons with power outputs greater than 10 kW c.w. or 100 kW pulsed at frequencies from 50 MHz to 30 GHz. Factors affecting the satisfactory operation of amplifiers include cooling, matching and protection circuits are discussed. The paper concludes with a summary of the state of the art for the different technologies.

  9. Passive Q-switching in CW-CO2 laser with SF6 as an intracavity saturable absorber

    A passive Q-switching was applied to a tunable CW CO2 laser with output power about 3.5 W using SF6 as a saturable absorber inside the cavity. The Q-Switching phenomenon was studied ( pulse shape, pulse duration, repetition rate and conditions of its generation ) at the spectral lines of 10P(10), 10P(26), 10P(28) and 10P(30) from the branch of 10P of CO2 laser. These lines had a weak absorption in relation to other lines of this branch, under SF6 pressure till 0.5 mbar. To control the behaviour of such phenomenon, the gases He and Xe were added separately to SF6. It was observed that the Q-switching phenomenon was depended on the added gas pressure of Xe and He, through the repetitive rate of pulses , duration and energy of generated laser pulse. A computational program was written to calculate the Q-switching pulses parameters under similar conditions as those applied in the case of SF6+He mixture. A comparison was made with the experimental data , not so big discrepancies were observed between them. In addition to that, absorption coefficients of SF6 were determined in two cases: the first one when the absorption cell was located outside the laser cavity, and the second one when the cell was located inside the cavity. On the basis of obtained coefficients the absorption cross sections of SF6 were found and compared with NIST database.(author)

  10. Optical features of Ca4NdO(BO3)3:Yb single crystals under CW laser illumination

    Optical treatment of Ca4NdO(BO3)3:Yb under continuous laser illumination at different wavelengths led to substantial changes of optical absorption and optical second harmonic generation. The treatment was performed successively by infrared (780 nm), red (650 nm), green (532 nm) and blue (405 nm) laser wavelengths with powers varying within the 200-400 mW range. We demonstrated enhancement of the optical second harmonic generation in the Ca4NdO(BO3)3:Yb (1.9% in weighting unit) crystals under the influence of the green cw laser at 532 nm. The principal changes were observed after 15 min of the treatment. A correlation between the occurrence of the hyperfine structure in the absorption spectra and the enhancement of the optical second harmonic generation was found. The additional treatment by the blue laser led to disappearance of appeared photo-induced changes of absorption and decrease of the optical second harmonic generation. It is principal that the effect is non-reversible in time and it does not depend on the photo-inducing light polarization. The principal origin of the observed photo-induced optical second harmonic generation is photo-polarization of the particular rare earth localized levels and formation of the stable polarized states due to the presence of Yb ions, playing crucial role. No such effects were observed in pure Ca4NdO(BO3)3.

  11. More than 100 channel supercontinuum CW optical source with precise 25GHz spacing for 10Gbit/s DWDM systems

    Wang, Jianping; Nan, Yinbo; Zhou, Xianwei

    2006-01-01

    We experimentally demonstrate the generation of supercontinuum (SC) with a 12.5GHz DFB/EAM ultrashort optical pulse broadened in the high nonlinear fiber (HNLF). Through longitudinal mode-carving of the SC spectrum, a novel multiwavelength continuous wave (CW) optical source with precise 25GHz channel spacing is realized. The bit error rate (BER) curve and eye diagram show that the multiwavelength CW optical source is promising for dense wavelength division multiplexing (DWDM) systems.

  12. High-Power Testing of the APT Power Coupler

    Schmierer, E. N.; Chan, K. C. D.; Gautier, D. C.; Gioia, J. G.; Haynes, W. B.; Krawczyk, F. L.; Madrid, M. A.; Schrage, D. L.; Waynert, J. A.; Rusnak, B.

    2000-01-01

    For the baseline APT (Accelerator Production of Tritium) linac design, power couplers are required to transmit 210-kW of CW RF power to the superconducting cavities. These APT couplers operate at 700 MHz, have a coaxial design and an adjustable coupling to the superconducting cavities. Since May 1999, we have been testing couplers of this design on a room-temperature test stand. We completed tests at transmitted-power and reflected-power conditions up to 1 MW. We also tested the couplers with...

  13. Experimental characterization of a micro-hole drilling process with short micro-second pulses by a CW single-mode fiber laser

    Tu, Jay; Paleocrassas, Alexander G.; Reeves, Nicholas; Rajule, Nilesh

    2014-04-01

    Laser ablation with pulse durations in a few microseconds is a viable solution for micro-hole drilling applications which require large material removal rate (MRR) with moderate hole quality. However, the body of work regarding short microsecond laser drilling/ablation is small. The objective of this paper is to experimentally characterize this short micro-second laser micro-hole drilling technique using a 300 W, CW, single-mode fiber laser. This CW fiber laser is controlled to produce modulated pulses from 1 μs to 8 μs and these modulated laser pulses have a unique profile which contains an initial spike with a peak power of 1500 W for 1 μs, followed by the steady state power of 300 W. Because of its excellent beam quality, the laser beam produced by this fiber laser can be focused to a small spot size of 10 μm to achieve very high power density up to 1.9 GW/cm2. With one single laser pulse at approximately 1 μs, a blind hole of 167 μm in depth and 23 μm in opening diameter can be created in a stainless substrate. The experimental characterization of this micro-hole drilling process includes laser control, laser beam characterization, hole formation, photodiode measurements of the vapor intensity, high-speed photography of vapor/plasma formation, and spectroscopic measurements of plasma. The results show that, due to very high irradiance of the fiber laser beam, the absorbed energy not only is sufficient to melt and vaporize the material, but also is able to dissociate vapor into intense plasma at temperatures over 16,000 K. The hole drilling mechanism by this short microsecond laser ablation is due to a combination of adiabatic evaporation and ejection of fine droplets.

  14. Solid state high power RF system for superconducting cavities

    Solid State High Power RF System is proposed for XFEL and ILC. It includes individual RF power supply for each SC cavity and common control system. Each RF power supply includes Solid State Generator, circulator and Q-tuner. Triggering, synchronization, output power and phase of each Solid State Generator are controlled from the common control system through fiber-optic lines. Main parameters of Solid State Generator are: frequency 1.3 GHz, peak power 128 kW, pulse length 1.4 msec, repetition rate 10 Hz, average power 1.8 kW, CW power 2.5 kW. Advantages of Solid State High Power RF System are: simple triggering, synchronization, output power and phase adjustment for all cavities separately, operation both in pulse and in CW modes, unlimited lifetime, no high voltage, no oil-tank, compactness.

  15. Application of high power microwave vacuum electron devices

    High power microwave vacuum electron devices can work at high frequency, high peak and average power. They have been widely used in military and civil microwave electron systems, such as radar, communication,countermeasure, TV broadcast, particle accelerators, plasma heating devices of fusion, microwave sensing and microwave heating. In scientific research, high power microwave vacuum electron devices are used mainly on high energy particle accelerator and fusion research. The devices include high peak power klystron, CW and long pulse high power klystron, multi-beam klystron,and high power gyrotron. In national economy, high power microwave vacuum electron devices are used mainly on weather and navigation radar, medical and radiation accelerator, TV broadcast and communication system. The devices include high power pulse and CW klystron, extended interaction klystron, traveling wave tube (TWT), magnetron and induced output tube (IOT). The state of art, common technology problems and trends of high power microwave vacuum electron devices are introduced in this paper. (authors)

  16. Resonant High Power Combiners

    Langlois, Michel; Peillex-Delphe, Guy

    2005-01-01

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

  17. Non-invasive optoacoustic temperature determination during retinal cw-laser treatments

    Kandulla, Jochen; Elsner, Hanno; Sandeau, Julien; Birngruber, Reginald; Brinkmann, Ralf

    2006-02-01

    In almost all retinal laser treatments the therapeutic effect is initiated by a transient temperature increase. Due to differences in tissue properties and physiology like pigmentation and vascular blood flow an individually different temperature increase might occur with crucial effects on the therapeutic benefit of the treatment. In order to determine the individual retinal temperature increase during cw-laser irradiation in real-time we developed a non-invasive method based on optoacoustics. Simultaneously to the cw-laser irradiation (λ = 810 nm, P pressure wave, which amplitude was found to be temperature dependent following in good approximation a 2 nd order polynomial. The pressure wave was measured by an ultrasonic transducer embedded in a contact lens placed on the cornea. The experiments were performed in-vivo on rabbits. Simultaneous measurements with a miniaturized thermocouple showed a similar slope with a maximum local deviation of 0.4 °C for a temperature increase of 5.5 °C. On two rabbits measurements pre and post mortem at the same location were performed. The temperature increase after 60 s was found to raise by 12.0 % and 66.7 % post mortem, respectively. These data were used to calculate the influence of heat convection by blood circulation using a numerical model based on two absorbing layers and assuming a constant perfusion rate for the choriocapillaris and the choroid. Overall the presented optoacoustic method seems feasible for a non-invasive real-time determination of cw-laser induced retinal temperature increases and might serve as a temperature based dosimetry control during retinal laser treatments.

  18. First results from the Cornell high Q cw full linac cryo- module

    Eichhorn, R.; Furuta, F.; He, Y.; Ge, M.; Hoffstaetter, G.; O'Connell, T.; Quigley, P.; Sabol, D.; Sears, J.; Smith, E.; Liepe, M.; Markham, S.; Bullock, B.; Elmore, B.; Kaufman, J.; Conway, J.; Veshcherevich, V.

    2015-12-01

    Cornell University has finished building a 10 m long superconducting accelerator module as a prototype of the main linac of a proposed ERL facility. This module houses 6 superconducting cavities- operated at 1.8 K in continuous wave (CW) mode - with individual HOM absorbers and one magnet/ BPM section. In pushing the limits, a high quality factor of the cavities (2•1010) and high beam currents (100 mA accelerated plus 100 mA decelerated) were targeted. The design of the cryomodule and the results of components tested before assembly will be presented in this paper.

  19. Application of digital signal processing in locking of CW lasers on optical frequency combs

    Čížek, Martin; Číp, Ondřej; Šmíd, Radek; Hrabina, Jan; Mikel, Břetislav; Lazar, Josef

    Budva : University of Montenegro, 2013. s. 146. [ALT´13. Annual International Conference on Advanced Laser Technologies /21./. 16.09.2013-20.09.2013, Budva] R&D Projects: GA ČR GPP102/11/P819; GA ČR GAP102/10/1813; GA TA ČR TA01010995; GA MŠk ED0017/01/01; GA MŠk EE2.4.31.0016 Institutional support: RVO:68081731 Keywords : digital signal processing * CW lasers * optical frequency combs Subject RIV: BH - Optics, Masers, Lasers

  20. ARBRES: Light-weight CW/FM SAR sensors for small UAVs

    Xavier Fabregas; Mallorqui, Jordi J.; Antoni Broquetas; Rene Acevo-Herrera; Albert Aguasca

    2013-01-01

    This paper describes a pair of compact CW/FM airborne SAR systems for small UAV-based operation (wingspan of 3.5 m) for low-cost testing of innovative SAR concepts. Two different SAR instruments, using the C and X bands, have been developed in the context of the ARBRES project, each of them achieving a payload weight below 5 Kg and a volume of 13.5 dm3 (sensor and controller). Every system has a dual receiving channel which allows operation in interferometric or polarimetric modes. Planar pri...

  1. An FM-CW scatterometer radar. Design, implementation and use on natural surfaces

    A C-band (5.3 GHz) scatterometer radar has been developed and successfully employed for backscattering measurements of natural surfaces. The instruments is based on a FM-CW scheme with a 300 MHz modulation interval. With this configuration, range resolution and independent samples within the sensor footprint area can be obtained. The aim of this work is to validate scattering models for parameter retrieval from SAR data. An example of scattering data acquisition is described in this paper: radar data have been collected in the 23 degrees to 60 degrees incidence angle interval over bare soil areas with different surface roughness and soil moisture

  2. Remote wind sensing with a CW diode laser lidar beyond the coherence regime

    Hu, Qi; Rodrigo, Peter John; Pedersen, Christian

    2014-01-01

    We experimentally demonstrate for the first time (to our knowledge) a coherent CW lidar system capable of wind speed measurement at a probing distance beyond the coherence regime of the light source. A side-by-side wind measurement was conducted on the field using two lidar systems with identical...... optical designs but different laser linewidths. While one system was operating within the coherence regime, the other was measuring at least 2.4 times the coherence range. The probing distance of both lidars is 85 m and the radial wind speed correlation was measured to be r2=0.965 between the two lidars...

  3. Application of digital signal processing in locking of CW lasers on optical frequency combs

    Čížek, Martin; Číp, Ondřej; Šmíd, Radek; Hrabina, Jan; Mikel, Břetislav; Lazar, Josef

    Budva: University of Montenegro, 2013. s. 146. [ALT´13. Annual International Conference on Advanced Laser Technologies /21./. 16.09.2013-20.09.2013, Budva] R&D Projects: GA ČR GPP102/11/P819; GA ČR GAP102/10/1813; GA TA ČR TA01010995; GA MŠk ED0017/01/01; GA MŠk EE2.4.31.0016 Institutional support: RVO:68081731 Keywords : digital signal processing * CW lasers * optical frequency combs Subject RIV: BH - Optics, Masers, Lasers

  4. A Method to Assess Robustness of GPS C/A Code in Presence of CW Interferences

    Beatrice Motella

    2010-01-01

    Full Text Available Navigation/positioning platforms integrated with wireless communication systems are being used in a rapidly growing number of new applications. The mutual benefits they can obtain from each other are intrinsically related to the interoperability level and to a properly designed coexistence. In this paper a new family of curves, called Interference Error Envelope (IEE, is used to assess the impact of possible interference due to other systems (e.g., communications transmitting in close bandwidths to Global Navigation Satellite System (GNSS signals. The focus is on the analysis of the GPS C/A code robustness against Continuous Wave (CW interference.

  5. Correlation between EBIC contrast and residual defects in slip-free CW laser annealed silicon

    The electron beam induced current (EBIC) mode of the scanning electron microscope (SEM) has been used to characterize the quality of CW laser annealed Si layers. In this investigation we show that the EBIC micrographs can be correlated directly with the kinematic contrast from highly strained crystal zones delineated by transmission X-ray topography. The combined optical, X-ray and electron microscope (TEM, SEM) studies enabled us to identify the residual defects responsible for the EBIC contrast. High voltage electron microscopy (HVEM) analysis revealed a dense network of dislocations in the epitaxially regrown Si layers. (author)

  6. Cavity-Enhanced Raman Spectroscopy of Natural Gas with Optical Feedback cw-Diode Lasers

    Hippler, M

    2015-01-01

    We report on improvements made on our previously introduced technique of cavity-enhanced Raman spectroscopy (CERS) with optical feedback cw-diode lasers in the gas phase, including a new mode-matching procedure which keeps the laser in resonance with the optical cavity without inducing long-term frequency shifts of the laser, and using a new CCD camera with improved noise performance. With 10 mW of 636.2 nm diode laser excitation and 30 s integration time, cavity enhancement achieves noise-eq...

  7. Adaptive polarimetric processing for ground clutter suppression in FM-CW radars

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

    Polarimetric radar signal processing is used in the Delft FM-CW radar to suppress coherent nonmoving radar targets. A single co-polar receiver still suffices to determine the full-polarimetric characteristics of targets under the condition that successive measurements are performed with calibrated multistate (0 - 45 - 90 degrees) polarizers which are used in a fast-switching linear polarization mode. Clutter reduction results are shown, based on dedicated polarimetry processing, in order to get optimum suppression per range cell at - per range cell - selected elliptical polarizations in the receiver channel and fixed linear polarization in the transmitter.

  8. An FM-CW scatterometer radar. Design, implementation and use on natural surfaces

    Sabatelli, V.; Casarano, D.; Buono, G.; Paparella, F.; Posa, F. [I.N.F.M., Bari (Italy); ENEA, Rotondella (Italy). Centro Ricerche della Trisaia

    1999-08-01

    A C-band (5.3 GHz) scatterometer radar has been developed and successfully employed for backscattering measurements of natural surfaces. The instruments is based on a FM-CW scheme with a 300 MHz modulation interval. With this configuration, range resolution and independent samples within the sensor footprint area can be obtained. The aim of this work is to validate scattering models for parameter retrieval from SAR data. An example of scattering data acquisition is described in this paper: radar data have been collected in the 23 degrees to 60 degrees incidence angle interval over bare soil areas with different surface roughness and soil moisture.

  9. Fourier-Bessel Field Calculation and Tuning of a CW Annular Array

    Fox, Paul D.; Cheng, Jiqi; Lu, Jian-yu

    2002-01-01

    A 1-D Fourier-Bessel series method for computing and tuning the linear lossless field of flat continuous wave (CW) annular arrays is given and discussed with both numerical simulation and experimental verification. The technique provides a new method for modelling and manipulating the propagated...... field by linking the quantized surface pressure profile to a set of limited diffraction Bessel beams propagating into the medium. In the limit, these become a known set of nondiffracting Bessel beams satisfying the lossless linear wave equation, which allow us to derive a linear matrix formulation for...

  10. Clinical trials in near infrared fluorescence imaging with IRDye 800CW

    Draney, Daniel R.

    2015-03-01

    A monofunctional, heptamethine dye, IRDye® 800CW, is being manufactured under GMP conditions for use in human clinical trials. When attached to a suitable targeting agent and paired with an appropriate camera system, the dye allows Near Infrared (NIR) fluorescence imaging of tumor tissue during surgery. The talk will describe the properties of the dye and give an overview of current and planned clinical trials in Europe and the USA. The dye is available in both the NHS ester and carboxylate forms for conjugation to targeting molecules. A GMP toxicology study of the dye was described in a previous publication.

  11. High power and spectral purity continuous-wave photonic THz source tunable from 1 to 4.5 THz for nonlinear molecular spectroscopy

    We report a diffraction-limited photonic terahertz (THz) source with linewidth 25 μW of single-frequency tunable CW THz output power scalable to >1 mW with proper choice of pump laser wavelength. (paper)

  12. Impedance matching network systems using stub-lines of 20 kW CW RF amplifier for SKKUCY-9 compact cyclotron

    Lee, Seung Hyun; Song, Ho Seung; Kim, Jeong Hwan; Cong, Truong Van; Kim, Hui Su; Yeon, Yeong Heum; Lee, Yong seok; Chai, Jong Seo

    2015-01-01

    The SKKUCY-9 is a compact cyclotron for radioactive isotopes (RI) production of positron emission tomography (PET). Charged particles such as H-ions are accelerated azimuthally within a high intensity electric field (E-field) generated from a radio frequency (RF) system in cyclotron. A high power RF signal is transmitted from an RF amplifier to an RF resonating cavity. The RF system of the SKKUCY-9 operates in continuous wave (CW) mode. If an ion beam were accelerated in the cyclotron, the vacuum level and permittivity would be changed because of beam loading. It causes an impedance shift of the RF resonating cavity. This impedance mismatch generates reflected power that decreases the RF transmitting power. To prevent this situation, an impedance matching system is necessary. This paper describes the impedance matching system of a 20 kW RF amplifier in an SKKUCY-9 compact cyclotron. The impedance matching circuit was designed using both an input stage and output stage, which are divided between the cathode and anode in a vacuum tube that is used as an amplifying device. The equivalent circuit of the matching system is made of passive elements. The characteristic results of designed circuit were calculated using a Smith chart. In assembling, the inductors were replaced by movable stub-line structures. The dimensions of the stub-line structures were optimized with equations and the measurement results. The experiment was performed to find the result values of matching circuit impedance and RF power amplitude.

  13. Improvements of PKU PMECRIS for continuous hundred hours CW proton beam operation

    In order to improve the source stability, a long term continuous wave (CW) proton beam experiment has been carried out with Peking University compact permanent magnet 2.45 GHz ECR ion source (PKU PMECRIS). Before such an experiment a lot of improvements and modifications were completed on the source body, the Faraday cup and the PKU ion source test bench. At the beginning of 2015, a continuous operation of PKU PMECRIS for 306 h with more than 50 mA CW beam was carried out after success of many short term tests. No plasma generator failure or high voltage breakdown was observed during that running period and the proton source reliability is near 100%. Total beam availability, which is defined as 35-keV beam-on time divided by elapsed time, was higher than 99% [S. X. Peng et al., Chin. Phys. B 24(7), 075203 (2015)]. A re-inspection was performed after another additional 100 h operation (counting time) and no obvious sign of component failure was observed. Counting the previous source testing time together, this PMECRs longevity is now demonstrated to be greater than 460 h. This paper is mainly concentrated on the improvements for this long term experiment

  14. Workshops on Science Enabled by a Coherent, CW, Synchrotron X-ray Source, June 2011

    Brock, Joel

    2012-01-03

    In June of 2011 we held six two-day workshops called "XDL-2011: Science at the Hard X-ray Diffraction Limit". The six workshops covered (1) Diffraction-based imaging techniques, (2) Biomolecular structure from non-crystalline materials, (3) Ultra-fast science, (4) High-pressure science, (5) Materials research with nano-beams and (6) X-ray photon correlation spectroscopy (XPCS), In each workshop, invited speaker from around the world presented examples of novel experiments that require a CW, diffraction-limited source. During the workshop, each invited speaker provided a one-page description of the experiment and an illustrative graphic. The experiments identified by the workshops demonstrate the broad and deep scientific case for a CW coherent synchrotron x-ray source. The next step is to perform detailed simulations of the best of these ideas to test them quantitatively and to guide detailed x-ray beam-line designs. These designs are the first step toward developing detailed facility designs and cost estimates.

  15. Improvements of PKU PMECRIS for continuous hundred hours CW proton beam operation

    Peng, S. X.; Zhang, A. L.; Ren, H. T.; Zhang, T.; Zhang, J. F.; Xu, Y.; Guo, Z. Y.; Chen, J. E.

    2016-02-01

    In order to improve the source stability, a long term continuous wave (CW) proton beam experiment has been carried out with Peking University compact permanent magnet 2.45 GHz ECR ion source (PKU PMECRIS). Before such an experiment a lot of improvements and modifications were completed on the source body, the Faraday cup and the PKU ion source test bench. At the beginning of 2015, a continuous operation of PKU PMECRIS for 306 h with more than 50 mA CW beam was carried out after success of many short term tests. No plasma generator failure or high voltage breakdown was observed during that running period and the proton source reliability is near 100%. Total beam availability, which is defined as 35-keV beam-on time divided by elapsed time, was higher than 99% [S. X. Peng et al., Chin. Phys. B 24(7), 075203 (2015)]. A re-inspection was performed after another additional 100 h operation (counting time) and no obvious sign of component failure was observed. Counting the previous source testing time together, this PMECRs longevity is now demonstrated to be greater than 460 h. This paper is mainly concentrated on the improvements for this long term experiment.

  16. Design of a CW high charge state heavy ion RFQ for SSC-LINAC

    The new linac injector SSC-LINAC has been proposed to replace the existing Separator Sector Cyclotron (SSC). This effort is to improve the beam efficiency of the Heavy Ion Research Facility of Lanzhou (HIRFL). As a key component of the linac, a continuous-wave (CW) mode high charge state heavy ion radio-frequency quadrupole (RFQ) accelerator has been designed. It accelerates ions with the ratio of mass to charge up to 7 from 3.728 keV/u to 143 keV/u. The requirements of CW mode operation and the transportation of intense beam have been considered as the greatest challenges. The design is based on 238U34+ beams, whose current is 0.5 pmA (0.5 particle mili-ampere, which is the measured 17 emA electric current divided by charge state of heavy ions). It achieves the transmission efficiency of 94% with 2508.46 mm long vanes in simulation. To improve the transmission efficiency and quality of the beams, the phase advance has been taken into account to analyze the reasons of beam loss and emittance growth. Parametric resonance and beam mismatch have been carefully avoided by adjusting the structure parameters. The parameter-sensitivity of the design is checked by transportation simulations of various input beams. To verify the applicability of machining, the effects of different vane manufacturing methods on beam dynamics are presented in this paper.

  17. MBE growth of active regions for electrically pumped, cw-operating GaSb-based VCSELs

    Kashani-Shirazi, K.; Bachmann, A.; Boehm, G.; Ziegler, S.; Amann, M.-C.

    2009-03-01

    Electrically pumped, cw-operating, single-mode GaSb-based VCSELs are attractive light sources for trace-gas sensing systems using tunable diode laser absorption spectroscopy (TDLAS) [A. Vicet, D.A. Yarekha, A. Pérona, Y. Rouillard, S. Gaillard, Spectrochimica Acta Part A 58 (2002) 2405-2412]. Only recently, the first electrically pumped (EP) devices emitting at 2.325 μm in cw-mode at room temperature have been reported [A. Bachmann, T. Lim, K. Kashani-Shirazi, O. Dier, C. Lauer, M.-C. Amann, Electronics Letters 44(3) (2008) 202-203]. The fabrication of these devices employs the molecular beam epitaxy (MBE) growth of GaSb/AlAsSb-distributed Bragg mirrors, a multi-quantum-well active region made of AlGaAsSb/InGaAsSb and an InAsSb/GaSb-buried-tunnel junction. As VCSELs are usually driven under high injection rates, an optimum electrical design of active regions is essential for high-performance devices. In this paper we present an enhanced simulation of current flow in the active region under operation conditions. The calculation includes carrier transport by drift, diffusion and tunneling. We discuss different design criteria and material compositions for active regions. Active regions with various barrier materials were incorporated into edge emitter samples to evaluate their performance. Aluminum-containing barriers show better internal efficiency compared to active regions with GaSb as the barrier material.

  18. Improvements of PKU PMECRIS for continuous hundred hours CW proton beam operation

    Peng, S. X., E-mail: sxpeng@pku.edu.cn; Ren, H. T.; Zhang, T.; Zhang, J. F.; Xu, Y.; Guo, Z. Y. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Zhang, A. L.; Chen, J. E. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2016-02-15

    In order to improve the source stability, a long term continuous wave (CW) proton beam experiment has been carried out with Peking University compact permanent magnet 2.45 GHz ECR ion source (PKU PMECRIS). Before such an experiment a lot of improvements and modifications were completed on the source body, the Faraday cup and the PKU ion source test bench. At the beginning of 2015, a continuous operation of PKU PMECRIS for 306 h with more than 50 mA CW beam was carried out after success of many short term tests. No plasma generator failure or high voltage breakdown was observed during that running period and the proton source reliability is near 100%. Total beam availability, which is defined as 35-keV beam-on time divided by elapsed time, was higher than 99% [S. X. Peng et al., Chin. Phys. B 24(7), 075203 (2015)]. A re-inspection was performed after another additional 100 h operation (counting time) and no obvious sign of component failure was observed. Counting the previous source testing time together, this PMECRs longevity is now demonstrated to be greater than 460 h. This paper is mainly concentrated on the improvements for this long term experiment.

  19. Department of Energy's ground penetrating radar (GPR): an FM-CW system

    Koppenjan, Steven; Bashforth, Michael B.

    1993-11-01

    The United States Department of Energy's Special Technologies Laboratory (STL) has been actively involved with ground penetrating radar technology since 1968. A ground penetrating radar will utilize the reflective properties of various dielectric interfaces and nonhomogeneous materials in the soil to obtain target information. The production of total site characterization data will require implementation of advanced imaging techniques, data fusion, highly accurate decision, and delineation of subsurface objects. To meet these new technical requirements for high resolution data, STL is moving forward with advances to GPR technology with development of a stepped FM-CW Ground Penetrating Radar. This unit operates over a frequency range of 196 MHz to 708 MHz and produces phase-coherent data. It has a real-time display of data, saves the data to floppy discs and can also produce hard copies in the field. This system has successfully detected targets ranging from 60 mm projectiles to 500 pound bombs up to 15 feet deep. Additional field deployment of the GPR produced successful results on other metallic and nonmetallic targets. This paper outlines the theory of operation of a Stepped Frequency Modulated, Continuous-Wave (FM-CW) Ground Penetrating Radar, provides a technical description of the unit, data display format and presents some sample data sets.

  20. Simulátor funkce FM-CW dálkoměru

    Bačík, Martin

    2012-01-01

    Táto práca popisuje problematiku návrhu simulátoru FM-CW diaľkomeru. Výber optimálnej metódy realizácie. Práca informuje o základných vlastnostiach kontinuálne pracujúcich radarov. Práca zahrňuje analýzu chybovosti reálneho diaľkomeru a numerický odhad maximálnej chyby celého reálneho zariadenia. Obsahuje detailné blokové schéma simulátoru funkcie FM-CW diaľkomeru a počítačovú simuláciu funkcie generátora kmitočtovo modulovaného signálu, demodulátoru. Ďalej práca zahŕňa úplné konštrukčné podk...

  1. ALMA Data Suggest the Presence of Spiral Structure in the Inner Wind of CW Leo

    Ward, H.; Leen, D.

    2015-12-01

    Evolved low-mass stars lose a significant fraction of their mass through stellar winds. While the overall morphology of the stellar wind structure during the asymptotic giant branch (AGB) phase is thought to be roughly spherically symmetric, the morphology changes dramatically during the post-AGB and planetary nebula phase, during which bipolar and multi-polar structures are often observed. We have observed the close-by carbon-rich AGB star CW Leo using ALMA (Cycle 0) in band 9 around 650 GHz. The channel maps and position-velocity diagram of the 13CO J=6-5 line show a complex structure. Using detailed 3D radiative transfer models, we show that the curved structure in the position velocity map of the 13CO J=6-5 line can be explained by a spiral structure in the inner wind of CW Leo, probably induced by a binary companion. From modelling the ALMA data, we deduce that the potential orbital axis for the binary system lies at a position angle of 10 to 20 degrees to the north-east and that the spiral structure is seen almost edge-on. We infer an orbital period of 55 yr and a binary separation of 25 au (or 8.2 stellar radii). We tentatively estimate that the companion is an unevolved low-mass main sequence star.

  2. High power infrared QCLs: advances and applications

    Patel, C. Kumar N.

    2012-01-01

    QCLs are becoming the most important sources of laser radiation in the midwave infrared (MWIR) and longwave infrared (LWIR) regions because of their size, weight, power and reliability advantages over other laser sources in the same spectral regions. The availability of multiwatt RT operation QCLs from 3.5 μm to >16 μm with wall plug efficiency of 10% or higher is hastening the replacement of traditional sources such as OPOs and OPSELs in many applications. QCLs can replace CO2 lasers in many low power applications. Of the two leading groups in improvements in QCL performance, Pranalytica is the commercial organization that has been supplying the highest performance QCLs to various customers for over four year. Using a new QCL design concept, the non-resonant extraction [1], we have achieved CW/RT power of >4.7 W and WPE of >17% in the 4.4 μm - 5.0 μm region. In the LWIR region, we have recently demonstrated QCLs with CW/RT power exceeding 1 W with WPE of nearly 10 % in the 7.0 μm-10.0 μm region. In general, the high power CW/RT operation requires use of TECs to maintain QCLs at appropriate operating temperatures. However, TECs consume additional electrical power, which is not desirable for handheld, battery-operated applications, where system power conversion efficiency is more important than just the QCL chip level power conversion efficiency. In high duty cycle pulsed (quasi-CW) mode, the QCLs can be operated without TECs and have produced nearly the same average power as that available in CW mode with TECs. Multiwatt average powers are obtained even in ambient T>70°C, with true efficiency of electrical power-to-optical power conversion being above 10%. Because of the availability of QCLs with multiwatt power outputs and wavelength range covering a spectral region from ~3.5 μm to >16 μm, the QCLs have found instantaneous acceptance for insertion into multitude of defense and homeland security applications, including laser sources for infrared

  3. Noise caused by a finite extinction ratio of the light modulator in CW cavity ring-down spectroscopy

    Huang, H.; Lehmann, K. K.

    2009-02-01

    A model is presented for the effect of a finite extinction ratio of the light modulator used in continuous wave cavity ring-down spectroscopy (CW-CRDS) experiments. We present a simple analytical expression for the minimum isolation required to prevent a significant increase in the fluctuations of the cavity decay rate, which determine the sensitivity of the method. We also present systematic measurements of the signal to noise in CW-CRDS as a function of the effective isolation of the light modulator, and excellent agreement with the model is found.

  4. Inefficient assembly limits transport and cell surface expression of HLA-Cw4 molecules in C1R.

    Zemmour, J

    1996-12-01

    HLA-C antigens are expressed to the cell surface at roughly 10% the level of HLA-B or -A, and their serological definition remains persistently difficult. To characterize the factors limiting surface expression, the processes of assembly and intracellular transport of HLA-Cw4 molecules were investigated in the C1R cell line. When appropriate peptides were added to cultured cells or in cell lysates significant amounts of conformed HLA-C molecules that associate with beta 2-microglobulin (beta 2 m) are detected, but are indeed not sufficient to restore expression to the level observed for HLA-A or -B molecules. Furthermore, a precursor/product relationship exists between the free class I heavy chain and the mature conformation of HLA-Cw4 molecules. Thus, HLA-C assembly promotes the conversion of HC-10-reactive molecules (weakly-beta 2m-associated non-ligand associated free HC form) into the beta 2m-associated class I molecules recognized by W6/32. To further investigate the factors that regulate cell surface expression, intracellular transport of HLA-Cw4 was studied in pulse chase analysis. In contrast to some HLA-A and B, maturation of HLA-Cw4 heavy chains and their export to the medial and trans-Golgi compartments are quite inefficient. After 4 h of chase period, roughly half of the pulse-labeled HLA-Cw4 molecules have transited to the medial-Golgi and acquired complex oligosaccharides characteristic of mature form. In addition, treatment with gamma-interferon does not appear to improve maturation of HLA-Cw4 heavy chains, suggesting that increased supply of peptides does not influence intracellular transport. Moreover, only a small fraction in the pool of HLA-Cw4 molecules was subsequently transported through the trans-Golgi network, as indicated by their acquisition of sialic acids. Taken together these studies show that HLA-Cw4 molecules are inefficiently transported through the Golgi apparatus and presumably retained in the endoplasmic reticulum or cis

  5. HLA-Cw Allele Frequency in Definite Meniere’s Disease Compared to Probable Meniere’s Disease and Healthy Controls in an Iranian Sample

    Sasan Dabiri

    2016-05-01

    Full Text Available Introduction Several lines of evidence support the contribution of autoimmune mechanisms in the pathogenesis of Meniere’s disease. The aim of this study was determining the association between HLA-Cw Alleles in patients with definite Meniere’s disease and patients with probable Meniere’s disease and a control group.  Materials and Methods: HLA-Cw genotyping was performed in 23 patients with definite Meniere’s disease, 24 with probable Meniere’s disease, and 91 healthy normal subjects, using sequence specific primers polymerase chain reaction technique. The statistical analysis was performed using stata 8 software.  Results: There was a significant association between HLA-Cw*04 and HLA-Cw*16 in both definite and probable Meniere’s disease compared to normal healthy controls. We observed a significant difference in HLA-Cw*12 frequencies between patients with definite Meniere’s disease compared to patients with probable Meniere’s disease (P=0.04. The frequency of HLA-Cw*18 is significantly higher in healthy controls (P=0.002.  Conclusion: Our findings support the rule of HLA-Cw Alleles in both definite and probable Meniere’s disease. In addition, differences in HLA-Cw*12 frequency in definite and probable Meniere’s disease in our study’s population might indicate distinct immune and inflammatory mechanisms involved in each condition.

  6. The Cornell Main Linac Cryomodule: A Full Scale, High Q Accelerator Module for cw Application

    Eichhorn, R.; Bullock, B.; Elmore, B.; Clasby, B.; Furuta, F.; He, Y.; Hoffstaetter, G.; Liepe, M.; O'Connell, T.; Conway, J.; Quigley, P.; Sabol, D.; Sears, J.; Smith, E.; Veshcherevich, V.

    Cornell University is in the process of building a 10 m long superconducting accelerator module as a prototype of the main linac of a proposed ERL facility. This module houses 6 superconducting cavities- operated at 1.8 K in continuous wave (CW) mode - with individual HOM absorbers and one magnet/BPM section. In pushing the limits, a high quality factor of the cavities (2•1010) and high beam currents (100 mA accelerated plus 100 mA decelerated) were targeted. We will review the design shortly and present the results of the components tested before the assembly. This includes data of the quality-factors of all 6 cavities that we produced and treated in-house, the HOM absorber performance measured with beam on a test set-up as well as testing of the couplers and the tuners.

  7. Study the spectroscopic of the SF6 using a CW-CO2 laser

    The aim of this work is to study the spectroscopic behaviour of the SF6, using a CW CO2 laser employing absorption and opto-acoustic cells. The behaviour of the absorption-lines of the SF6 was investigated in the 10.6 Mm region which was discussed in terms of suggested theoretical models. moreover, the respective linear absorption coefficient, the saturation and bleaching intensities, and variation in absorption coefficient with incident intensity, were determined using the conventional method. The cell characteristics were studied theoretically and the acoustic modes were computed and compared with experimental work for two different cells. The aim was to develop an optimized resonance cell for opto-acoustic measurements with SF6. (15 tabs., 48 figs., 92 refs.)

  8. Investigation of the neon 2p collisional excitation transfer processes via CW laser collisionally induced fluorescence

    We present a method for determining the 2p (in Paschen notation) collisional excitation transfer coefficients in noble gases using continuous-wave laser collisionally induced fluorescence (CW LCIF, i.e. fluorescence from an upper level which is not that of the laser transition). The technique requires isolation of the specific 2p coupling process under examination, whereby that process provides an important and quantifiable contribution to the LCIF. This is achieved by selecting appropriate laser excitation and LCIF transitions. For a neon discharge operating at pressures ranging from 1.5 to 8.0 Torr and currents from 1 to 10 mA, 2p coupling is by ground-state atom collisions and the largest coupling exists between adjacent states. We show that in certain cases excitation transfer plays an important role in the excited-state kinetics. (author)

  9. Similarity criteria in calculations of the energy characteristics of a cw oxygen – iodine laser

    The calculated and experimental data on the energy efficiency of a cw oxygen – iodine laser (OIL) are analysed based on two similarity criteria, namely, on the ratio of the residence time of the gas mixture in the resonator to the characteristic time of extraction of the energy stored in singlet oxygen td and on the gain-to-loss ratio Π. It is shown that the simplified two-level laser model satisfactorily predicts the output characteristics of OILs with a stable resonator at τd ≤ 7. Efficient energy extraction from the OIL active medium is achieved in the case of τd = 5 – 7, Π = 4 – 8. (lasers)

  10. Elastic modulus of SiCw/6061Al alloy composites as-squeeze-cast

    姜传海; 吴建生; 王德尊

    2001-01-01

    By using the system of image analyzer connected with scanning electron microscope, the whisker orientation in the SiCw/6061Al alloy composite as-squeeze-cast was measured. According to the shear lag model and the actual distribution function of whisker in composite, the inhomogeneity of elastic modulus in composite was analyzed. With the method of ultrasonic velocity, the elastic modulus of composite was measured. The results showed that, the whiskers of composite are preferred in an orientation normal to the direction of squeeze cast. The higher the volume fraction of whisker, the more extent of preferred orientation of it, and the inhomogeneity of elastic modulus is mainly due to the differences of whisker distribution in composite.

  11. Comprehensive numerical model for cw vertical-cavity surface-emitting lasers

    Hadley, G.R.; Lear, K.L.; Warren, M.E.; Choquette, K.D. [Sandia National Labs., Albuquerque, NM (United States); Scott, J.W. [Optical Concepts, Inc., Lompoc, CA (United States); Corzine, S.W. [Univ. of California, Santa Barbara, CA (United States)

    1995-03-01

    The authors present a comprehensive numerical model for vertical-cavity surface-emitting lasers that includes all major processes effecting cw operation of axisymmetric devices. In particular, the model includes a description of the 2D transport of electrons and holes through the cladding layers to the quantum well(s), diffusion and recombination processes of these carriers within the wells, the 2D transport of heat throughout the device, and a multi-lateral-mode effective index optical model. The optical gain acquired by photons traversing the quantum wells is computed including the effects of strained band structure and quantum confinement. They employ the model to predict the behavior of higher-order lateral modes in proton-implanted devices, and to provide an understanding of index-guiding in devices fabricated using selective oxidation.

  12. Distributed Sensor Particles for Remote Fluorescence Detection of Trace Analytes: UXO/CW; TOPICAL

    This report summarizes the development of sensor particles for remote detection of trace chemical analytes over broad areas, e.g residual trinitrotoluene from buried landmines or other unexploded ordnance (UXO). We also describe the potential of the sensor particle approach for the detection of chemical warfare (CW) agents. The primary goal of this work has been the development of sensor particles that incorporate sample preconcentration, analyte molecular recognition, chemical signal amplification, and fluorescence signal transduction within a ''grain of sand''. Two approaches for particle-based chemical-to-fluorescence signal transduction are described: (1) enzyme-amplified immunoassays using biocompatible inorganic encapsulants, and (2) oxidative quenching of a unique fluorescent polymer by TNT

  13. CW-OSL measurement protocols using optical fibre Al2O3:C dosemeters

    A new system for in vivo dosimetry during radiotherapy has been introduced. Luminescence signals from a small crystal of carbon-doped aluminium oxide (Al2O3:C) are transmitted through an optical fibre cable to an instrument that contains optical filters, a photomultiplier tube and a green (532 nm) laser. The prime output is continuous wave optically stimulated luminescence (CW-OSL) used for the measurement of the integrated dose. We demonstrate a measurement protocol with high reproducibility and improved linearity, which is suitable for clinical dosimetry. A crystal-specific minimum pre-dose is necessary for signal stabilisation. Simple background subtraction only partially removes the residual signal present at long integration times. Instead, the measurement protocol separates the decay curve into three individual components and only the fast and medium components were used. (authors)

  14. Multipolarisation FM-CW Doppler radar signal processing for nondistributed targets

    Niemeijer, R. J.; van Sinttruyen, J. S.; Ligthart, L. P.

    1991-06-01

    The Delft FM-CW radar is used to characterize radar targets based on their polarization parameters and Doppler velocity. Dedicated polarizers allow the radar system to have one receiver only. The domain of the polarization information interferes with the domain of the Doppler-velocity information. To split these domains and to retrieve the target parameters, a specific processing approach has been developed. The method has been implemented to run on one or more array processors, which are used as preprocessing units on a host computer. Besides the mathematical outlines of the method, the structure and organization of the processing units are discussed in the paper. Finally, some preliminary results of real-time performance measurements are shown.

  15. Ground clutter effects in an X-Band Solid State FM-CW weather radar

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

    A new X-Band Solid State FM-CW weather radar, developed at the Delft University, has been operational since 1989. Attention is given to ground clutter effects in the near range of this radar up to 15 km radar range. Two different types of cluttermaps are used for overall and detailed analysis of ground echoes in absence of rain. Clutter suppression techniques are elucidated. Improvement factors for weather/ground clutter ratios have to be interpreted with care in cases where coherent subtraction techniques are involved, since weather echoes in some areas can be nearly as much correlated as ground targets. Most of the cluttermap data handling and clutter suppression is done in real time by using general purpose computing equipment.

  16. Development of a cloud profiling FM-CW radar at 95 GHz and its preliminary results

    Takano, Toshiaki; Suga, Yumiro; Takei, Kentaro; Kawamura, Youhei; Sakai, Kurt; Kumagai, Hiroshi; Takamura, Tamio; Nakanishi, Yuji; Nakajima, Teruyuki

    2003-04-01

    A cloud profiling radar transmitting frequency-modulated continuous wave (FM-CW) at 95 GHz is developed for ground-based observations. Millimeter wave at 95 GHz is used to realize high sensitivity to small cloud particles. 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 15 km in height with a resolution of 15 m. The system was integrated and sensitivities and stabilities have been measured. Results of test measurements of clouds show that the system is sensitive and stable enough to observe various clouds.

  17. U.S. Army ultrahigh-resolution turbulence profiling FM-CW radar: description and data

    McLaughlin, Scott

    1992-08-01

    The U.S. Army Atmospheric Sciences Laboratory, White Sands Missile Range, New Mexico, recently received a new frequency-modulated continuous-wave (FM-CW) turbulence profiling radar. The radar is capable of high temporal (10 s) and spatial (1 to 2 m) resolution profiles of Cn2 up through 2 km above ground level. Data from this system can detect electromagnetic/atmospheric effects such as possible laser blooming/scattering regions, microwave tunneling and multipathing layers, and other clear-air and hydrometeor meteorological phenomena. The radar is superior in performance to previous high-resolution clear-air FM-CWs incorporating newer technologies and real-time processing. A system description and sample data are shown.

  18. Low-latitude Pi2 Pulsations observed by an FM-CW Radar and CPMN Stations

    Ikeda, A.; Yumoto, K.; Uozumi, T.; Shinohara, M.; Nozaki, K.; Yoshikawa, A.

    2008-12-01

    At the onset of magnetospheric substorms, impulsive hydromagnetic oscillations occur globally in the magnetosphere with a period range from 40 to 150 seconds [e.g. Saito, 1968]. They are called Pi 2 magnetic pulsations. Pi 2 has been studied with arrays of magnetometers on the ground and with in-situ observation by satellites [e.g. Yumoto, 2001]. However characteristics of Pi 2 electric pulsations in the low-latitude ionosphere have not been clearly identified yet. We have focused on measuring the Pi 2 electric pulsations by an FM-CW (Frequency Modulated Continuous Wave) radar and clarify their characteristics. In order to detect the ionospheric electric fields, we built a FM-CW (HF) radar at Sasaguri (Magnetic Latitude: 23.2 degree, Magnetic Longitude: 199.6 degree), Fukuoka, Japan in 2002. The radar provides the Doppler shift of launched wave frequencies, which corresponds to the height variation of the ionosphere, with a high- time resolution of 3 sec. When the eastward (westward) electric field penetrates into the low-latitude ionosphere, it drifts upward (downward) through the ExB drift. Thus, using the FM-CW radar we can measure east-west electric fields (Ey) in the ionosphere [see Ikeda et al., 2008]. In this study, we also used geomagnetic field data BH at Kujyu (KUJ; M. Lat. 23.6 degree, M. Lon. 203.2 degree), a part of Circum-pan Pacific Magnetic Network (CPMN) stations [cf., Yumoto et al., 2001]. The first Pi 2 event was observed at KUJ and Sasaguri simultaneously at 1332 UT (2232 LT) on 6 November, 2003. Also positive bay was detected in the H-component (BH) at KUJ. The dominant frequencies of the electric field Ey and magnetic field BH were identical. From a cross-correlation analysis between the BH at KUJ and Ey at Sasaguri, we found that the correlation coefficient is 0.80 and phase delay is about -100 degree. Takahashi et al. (JGR, 2001) showed the expected phase relation between magnetic field of cavity- mode Pi 2 and associated electric field

  19. High power proton accelerator for nuclear power plant

    The novel nuclear power system--Energy Amplifier, proposed by C. Rubbia, attracts the interest as a prior option for the development of the next generation nuclear power plant in the first half of the 21st century. The accelerator used to drive the system should provide proton beam power tens higher than that of LAMPF. The accelerator physics and technology have been advancing greatly since LAPMF was built more than 20 years ago. These new progresses become the essential basis for the intense beam accelerator to advance up to a much higher beam power. However, some challenges are still being faced, including beam loss, high efficiency, reliability, as well as some technical issues associated with high power CW operation. The accelerator design options to tackle with the difficulties are discussed. The suggestions on R and D of high power accelerator in China are presented

  20. Optimization of CW-OSL parameters for improved dose detection threshold in Al2O3:C

    Continuous wave optically stimulated luminescence (CW-OSL) is relatively a simple technique that offers good signal to noise ratio (SNR) and involves simple instrumentation. This study reports the influence and optimization of CW-OSL parameters on minimum detectable dose (MDD) using α-Al2O3:C phosphor. It is found that at a given stimulation intensity MDD in CW-OSL mode depends on signal integration time. At lower integration times MDD is inferior. It exhibits an improvement for intermediate values, shows a plateau region and deteriorates as integration time increases further. MDD is found to be ∼127 μGy at 4 mW/cm2 stimulation intensity for integration time of 0.1 s, which improves to ∼10.5 μGy for 60 s. At stimulation intensity of 72 mW/cm2, MDD is 37 μGy for integration time of 60 s and improves significantly to 7 μGy for 1 s. - Highlights: • CW-OSL parameters are optimized to obtain best SNR and MDD in Al2O3:C. • MDD is found to depend on signal integration time and stimulation intensity. • With time, MDD initially improves, stabilizes then deteriorates. • At a given intensity, MDD is optimum for a certain range of integration time

  1. Basics and first experiments demonstrating isolation improvements in the agile polarimetric FM-CW radar – PARSAX

    Krasnov, O.A.; Babur, G.P.; Wang, Z.; Ligthart, L.P.; Van der Zwan, F.

    2010-01-01

    The article describes the IRCTR PARSAX radar system, the S-band high-resolution Doppler polarimetric frequency modulated continuous wave (FM-CW) radar with dual-orthogonal sounding signals, which has the possibility to measure all elements of the radar target polarization scattering matrix simultane

  2. Commercial microwave space power

    This paper reports on central commercial space power, generating power via large scale solar arrays, and distributing power to satellites via docking, tethering or beamed power such as microwave or laser beams, that is being investigated as a potentially advantageous alternative to present day technology where each satellite carries its own power generating capability. The cost, size and weight for electrical power service, together with overall mission requirements and flexibility are the principal selection criteria, with the case of standard solar array panels based on the satellite, as the reference point. This paper presents and investigates a current technology design point for beamed microwave commercial space power. The design point requires that 25 kW be delivered to the user load with 30% overall system efficiency. The key elements of the design point are: An efficient rectenna at the user end; a high gain, low beam width, efficient antenna at the central space power station end, a reliable and efficient cw microwave tube. Design trades to optimize the proposed near term design point and to explore characteristics of future systems were performed. Future development for making the beamed microwave space power approach more competitive against docking and tethering are discussed

  3. Legal aspects of the licensing of nuclear power plants in Brazil

    The author gives a description of the licensing procedure regarding nuclear power plants in Brazil and points out the civil responsibility of the concessionaire in case of an infringement of obligations concerning supervision and maintenance of the plants. Public electric power utilities are supervised by the Ministry of Mines and Energy. (CW)

  4. Integrating in silico and in vitro analysis of peptide binding affinity to HLA-Cw*0102: a bioinformatic approach to the prediction of new epitopes.

    Valerie A Walshe

    Full Text Available BACKGROUND: Predictive models of peptide-Major Histocompatibility Complex (MHC binding affinity are important components of modern computational immunovaccinology. Here, we describe the development and deployment of a reliable peptide-binding prediction method for a previously poorly-characterized human MHC class I allele, HLA-Cw*0102. METHODOLOGY/FINDINGS: Using an in-house, flow cytometry-based MHC stabilization assay we generated novel peptide binding data, from which we derived a precise two-dimensional quantitative structure-activity relationship (2D-QSAR binding model. This allowed us to explore the peptide specificity of HLA-Cw*0102 molecule in detail. We used this model to design peptides optimized for HLA-Cw*0102-binding. Experimental analysis showed these peptides to have high binding affinities for the HLA-Cw*0102 molecule. As a functional validation of our approach, we also predicted HLA-Cw*0102-binding peptides within the HIV-1 genome, identifying a set of potent binding peptides. The most affine of these binding peptides was subsequently determined to be an epitope recognized in a subset of HLA-Cw*0102-positive individuals chronically infected with HIV-1. CONCLUSIONS/SIGNIFICANCE: A functionally-validated in silico-in vitro approach to the reliable and efficient prediction of peptide binding to a previously uncharacterized human MHC allele HLA-Cw*0102 was developed. This technique is generally applicable to all T cell epitope identification problems in immunology and vaccinology.

  5. ARBRES: light-weight CW/FM SAR sensors for small UAVs.

    Aguasca, Albert; Acevo-Herrera, Rene; Broquetas, Antoni; Mallorqui, Jordi J; Fabregas, Xavier

    2013-01-01

    This paper describes a pair of compact CW/FM airborne SAR systems for small UAV-based operation (wingspan of 3.5 m) for low-cost testing of innovative SAR concepts. Two different SAR instruments, using the C and X bands, have been developed in the context of the ARBRES project, each of them achieving a payload weight below 5 Kg and a volume of 13.5 dm3 (sensor and controller). Every system has a dual receiving channel which allows operation in interferometric or polarimetric modes. Planar printed array antennas are used in both sensors for easy system integration and better isolation between transmitter and receiver subsystems. First experimental tests on board a 3.2 m wingspan commercial radio-controlled aircraft are presented. The SAR images of a field close to an urban area have been focused using a back-projection algorithm. Using the dual channel capability, a single pass interferogram and Digital Elevation Model (DEM) has been obtained which agrees with the scene topography. A simple Motion Compensation (MoCo) module, based on the information from an Inertial+GPS unit, has been included to compensate platform motion errors with respect to the nominal straight trajectory. PMID:23467032

  6. Four years of operation of the 180MeV cw electron accelerator MAMI A

    This paper reports on a cw electron accelerator, consisting of two cascaded race track microtrons (14 and 180 MeV) with a Van de Graaff preaccelerator, taken into operation in March 1983. From the beginning the machine was relatively easy to operate and ran stable over many hours with a very good beam quality. The transverse beam emittance turned out to be slightly increased to about 0.014 π mm mrad at 183 MeV mainly due to geometrical and chromatic aberrations, whereas the measured energy spread of about 30 keV FWHM corresponded to the design value. Most of the technical problems were caused by the Van de Graaff preaccelerator and by its sensitivity to γ-radiation, which limited the maximum beam current to abut 65 μA at full energy. In the period from 1983 to 1987 MAMI A has been operated for 18,670 hours altogether and 17,160 hours for experiments in nuclear physics. Only 17% of this time were used for accelerator tuning and for the repair of acute failures

  7. ARBRES: Light-Weight CW/FM SAR Sensors for Small UAVs

    Xavier Fabregas

    2013-03-01

    Full Text Available This paper describes a pair of compact CW/FM airborne SAR systems for small UAV-based operation (wingspan of 3.5 m for low-cost testing of innovative SAR concepts. Two different SAR instruments, using the C and X bands, have been developed in the context of the ARBRES project, each of them achieving a payload weight below 5 Kg and a volume of 13.5 dm3 (sensor and controller. Every system has a dual receiving channel which allows operation in interferometric or polarimetric modes. Planar printed array antennas are used in both sensors for easy system integration and better isolation between transmitter and receiver subsystems. First experimental tests on board a 3.2 m wingspan commercial radio-controlled aircraft are presented. The SAR images of a field close to an urban area have been focused using a back-projection algorithm. Using the dual channel capability, a single pass interferogram and Digital Elevation Model (DEM has been obtained which agrees with the scene topography. A simple Motion Compensation (MoCo module, based on the information from an Inertial+GPS unit, has been included to compensate platform motion errors with respect to the nominal straight trajectory.

  8. Calibration of scattering and absorption properties of a liquid diffusive medium at NIR wavelengths. CW method.

    Martelli, Fabrizio; Zaccanti, Giovanni

    2007-01-22

    In spite of many progresses achieved both with theories and with experiments in studying light propagation through diffusive media, a reliable method for accurate measurements of the optical properties of diffusive media at NIR wavelengths is, in our opinion, still missing. It is therefore difficult to create a diffusive medium with well known optical properties to be used as a reference. In this paper we describe a method to calibrate the reduced scattering coefficient, mu'(s) , of a liquid diffusive medium and the absorption coefficient, mu(a), of an absorbing medium with a standard error smaller than 2% both on mu'(s) and on mu(a). The method is based on multidistance measurements of fluence into an infinite medium illuminated by a CW source. The optical properties are retrieved with simple inversion procedures (linear fits) exploiting the knowledge of the absorption coefficient of the liquid into which the diffuser and the absorber are dispersed. In this study Intralipid diluted in water has been used as diffusive medium and Indian ink as absorber. For a full characterization of these media measurements of collimated transmittance have also been carried out, from which the asymmetry factor of the scattering function of Intralipid and the single scattering albedo of Indian ink have been determined. PMID:19532267

  9. Super-resolution technique for CW lidar using Fourier transform reordering and Richardson-Lucy deconvolution.

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

    2014-12-15

    An interpolation method is described for range measurements of high precision altimetry with repeating intensity modulated continuous wave (IM-CW) lidar waveforms using binary phase shift keying (BPSK), where the range profile 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. This is then enhanced further using Richardson-Lucy deconvolution to greatly enhance the resolution of the pulse. We show the sampling resolution and pulse width can be enhanced by about two orders of magnitude using the signal processing algorithms presented, thus breaking the fundamental resolution limit for BPSK modulation of a particular bandwidth and bit rate. We demonstrate the usefulness of this technique for determining cloud and tree canopy thicknesses far beyond this fundamental limit in a lidar not designed for this purpose. PMID:25503046

  10. Stepped-frequency CW radar for concealed weapon detection and through-the-wall surveillance

    Hunt, Allen R.; Hogg, R. Douglas

    2002-08-01

    Both concealed weapons detection and through the wall surveillance are significant problems for both law enforcement and military personnel. While on the surface it would appear that these two problems are unrelated technologically, they do, in fact, share some common ground. A concealed weapon acts as resonant object, exhibiting electromagnetic resonance peaks at frequencies characteristic of the weapon's major dimensions. For handguns the frequency range of interest lies approximately between 450 MHz and 2 GHz. As it turns out, this is also a region over which many common building materials are largely transparent. As part of grant 97-IJ-CX-K013 from the National Institute of Justice, AKELA, Inc. has developed a stepped-frequency, CW radar that covers this frequency range. The radar is digitally synthesized and controlled and has a range resolution of approximately 4'. Digital waveform control gives the radar the ability to avoid interference with other electronic devices, to tailor data collection for signal processing requirements, and to change its sweep time in response to operational requirements. AKELA has developed a brassboard concealed weapons detector that uses this radar. A through the wall imaging system that uses the radar is currently in development under AFRL Contract F30602-00-C-0205.

  11. Crude Oil Remote Sensing, Characterization and Cleaning with CW and Pulsed Lasers

    Kukhtareva, Tatiana; Chirita, Arc; Gallegos, Sonia C.

    2014-01-01

    For detection, identification and characterization of crude oil we combine several optical methods of remote sensing of crude oil films and emulsions (coherent fringe projection illumination (CFP), holographic in-line interferometry (HILI), and laser induced fluorescence). These methods allow the three-dimensional characterization of oil spills, important for practical applications. Combined methods of CFP and HILI are described in the frame of coherent superposition of partial interference patterns. It is shown, that in addition to detection/identification laser illumination in the green-blue region can also degrade oil slicks. Different types of surfaces contaminated by oil spills are tested: oil on the water, oil on the flat solid surfaces and oil on the curved surfaces of pipes. For the detection and monitoring of the laser-induced oil degradation in pipes, coherent fiber bundles were used. Both continuous-wave (CW) and pulsed lasers are tested using pump-probe schemes. This finding suggests that properly structured laser clean-up can be an alternative environmentally-friendly method of decontamination, as compared to the currently used chemical methods that are dangerous to environment.

  12. Dancing with the Electrons: Time-Domain and CW In Vivo EPR Imaging

    Murali C. Krishna

    2008-01-01

    Full Text Available The progress in the development of imaging the distribution of unpaired electrons in living systems and the functional and the potential diagnostic dimensions of such an imaging process, using Electron Paramagnetic Resonance Imaging (EPRI, is traced from its origins with emphasis on our own work. The importance of EPR imaging stems from the fact that many paramagnetic probes show oxygen dependent spectral broadening. Assessment of in vivo oxygen concentration is an important factor in radiation oncology in treatment-planning and monitoring treatment-outcome. The emergence of narrow-line trairylmethyl based, bio-compatible spin probes has enabled the development of radiofrequency time-domain EPRI. Spectral information in time-domain EPRI can be achieved by generating a time sequence of T2* or T2 weighted images. Progress in CW imaging has led to the use of rotating gradients, more recently rapid scan with direct detection, and a combination of all the three. Very low field MRI employing Dynamic Nuclear polarization (Overhauser effect is also employed for monitoring tumor hypoxia, and re-oxygenation in vivo. We have also been working on the co-registration of MRI and time domain EPRI on mouse tumor models at 300 MHz using a specially designed resonator assembly. The mapping of the unpaired electron distribution and unraveling the spectral characteristics by using magnetic resonance in presence of stationary and rotating gradients in indeed ‘dancing with the (unpaired electrons’, metaphorically speaking.

  13. Functional role of the additional domains in inulosucrase (IslA from Leuconostoc citreum CW28

    Munguia Agustin

    2008-01-01

    Full Text Available Abstract Background Inulosucrase (IslA from Leuconostoc citreum CW28 belongs to a new subfamily of multidomain fructosyltransferases (FTFs, containing additional domains from glucosyltransferases. It is not known what the function of the additional domains in this subfamily is. Results Through construction of truncated versions we demonstrate that the acquired regions are involved in anchoring IslA to the cell wall; they also confer stability to the enzyme, generating a larger structure that affects its kinetic properties and reaction specificity, particularly the hydrolysis and transglycosylase ratio. The accessibility of larger molecules such as EDTA to the catalytic domain (where a Ca2+ binding site is located is also affected as demonstrated by the requirement of 100 times higher EDTA concentrations to inactivate IslA with respect to the smallest truncated form. Conclusion The C-terminal domain may have been acquired to anchor inulosucrase to the cell surface. Furthermore, the acquired domains in IslA interact with the catalytic core resulting in a new conformation that renders the enzyme more stable and switch the specificity from a hydrolytic to a transglycosylase mechanism. Based on these results, chimeric constructions may become a strategy to stabilize and modulate biocatalysts based on FTF activity.

  14. CW laser-induced photothermal conversion and shape transformation of gold nanodogbones in hydrated chitosan films

    We investigate the photothermal conversion and transformation of gold nanoparticles with an initial dogbone shape after dispersion in hydrated chitosan films, which is a representative model of biological tissue, and excitation by a CW diode laser for 1 min. Gold nanodogbones are observed to undergo a distinct modification above a sharp threshold of ∼11 W cm−2 and 110 °C. Surprisingly, the very same modification is achieved up to at least 36 W cm−2 and 250 °C. We use an analytical model derived from Gans theory to associate the change in color of the films with the change in shape statistics of these gold nanoparticles. This model proves both convenient and dependable. We interpret the photothermal transformation as a rearrangement of particles with a dogbone shape and an aspect ratio of 4.1 into rods with an aspect ratio of 2.5, where material from the end lobes of the dogbones may relocate to the waists of the rods. In turn, additional transitions to stable gold nanospheres may exhibit fairly slower kinetics.

  15. Gallium arsenide digital integrated circuits for controlling SLAC CW-RF systems

    In order to fill the PEP and SPEAR storage rings with beams from the SLC linac and damping rings, precise control of the linac subharmonic buncher and the damping ring RF is required. Recently several companies have developed resettable GaAs master/slave D-type flip-flops which are capable of operating at frequencies of 3 GHz and higher. Using these digital devices as frequency dividers, one can phase shift the SLAC CW-RF systems to optimize the timing for filling the storage rings. We have evaluated the performance of integrated circuits from two vendors for our particular application. Using microstrip circuit techniques, we have built and operated in the accelerator several chassis to synchronize a reset signal from the storage rings to the SLAC 2.856 GHz RF and to phase shift divide-by-four and divide-by-sixteen frequency dividers to the nearest 350 psec bucket required for filling. 4 refs., 4 figs., 2 tabs

  16. Second-harmonic generation from sub-monolayer molecular adsorbates using a c-w diode laser: Maui surface experiment

    Optical second-harmonic generation (SHG) can be an extremely sensitive tool for surface studies. The technique is capable of probing adsorbed molecules at various interfaces. It is based on the idea that SHG is forbidden in a medium with inversion symmetry, but necessarily allowed at a surface. To see such a surface nonlinear optical effect, high laser intensity is often needed. Thus, in the experiments reported so far, pulsed lasers were used exclusively. From the consideration for practical applications, however, the technique would look much more attractive if the bulky pulsed laser can be replaced by a simple inexpensive c-w diode laser. This paper describes the first demonstration of surface SHG with a c-w laser. 3 refs., 1 fig

  17. In situ measurements of OH radicals in dielectric barrier discharge plasmas with cw-cavity ring-down spectroscopy

    An apparatus of continuous wave cavity ring-down spectroscopy (cw-CRDS) has been constructed with the noise (RMS) equivalent absorption 3 x 10-9 cm-1. In situ quantitative measurements of OH radicals in dielectric barrier discharge (DBD) plasmas at low pressure using cw-CRDS are described. The influence of discharge voltage and pressure on number density of OH has been investigated. Results show that the OH production increases at low pressure with increasing discharge pressure; however, the number density of OH decreases due to electron attachment of H2O at higher pressure. The number density of OH radical increases with increasing discharge voltage and discharge frequency because of the increase of electron density and electron energy. (authors)

  18. Sensitivity and alternative operating point studies on a high charge CW FEL injector test stand at CEBAF

    A high charge CW FEL injector test stand is being built at CEBAF based on a 500 kV DC laser gun, a 1500 MHz room-temperature buncher, and a high-gradient (∼10 MV/m) CEBAF cryounit containing two 1500 MHz CEBAF SRF cavities. Space-charge-dominated beam dynamics simulations show that this injector should be an excellent high-brightness electron beam source for CW UV FELs if the nominal parameters assigned to each component of the system are experimentally achieved. Extensive sensitivity and alternative operating point studies have been conducted numerically to establish tolerances on the parameters of various injector system components. The consequences of degraded injector performance, due to failure to establish and/or maintain the nominal system design parameters, on the performance of the main accelerator and the FEL itself are discussed

  19. Whisker Orientation Function and Elastic Modulus of the as-cast 20%SiCw/Mg Composite

    2001-01-01

    The relationship between the plane-orientation function and the space-orientation function of whiskers in whisker-reinforced metal matrix composites was analyzed theoretically. The actual orientation of whiskers in the as-cast 20%SiCw/Mg composite (SiCw content in volume fraction) were investigated, and the elastic modulus of the composite was measured with an ultrasonic velocity analyzer. Results show that there is an evident difference be-tween the plane-orientation function and the space-orientation function of whiskers and the space-orientation function can represent the actual condition of the composite. Only by using the space-orientation function of whiskers, the difference of elastic modulus of the as-cast composite in different directions can be explained reasonably.

  20. Stability of noble-metal clusters on C/W(110) templates against CO and O2 exposure

    Full text: Small noble-metal (especially Au) clusters on oxidic supports have gained a lot of attention in the last years due to their high activity and selectivity as catalysts for CO oxidation. The importance of cluster-size effects and the influence of the substrate material are still discussed controversially. We introduce two differently carburized W(110) surfaces R(15x12)C/W(110) and R(15x3)C/W(110) as templates for the growth of different types of Au, Ag and Cu nanoclusters. In a first step towards exploring the catalytic properties these clusters we studied the stability of the nano-clusters against exposure to the reaction gases CO and O2 by scanning tunnelling microscopy. Differences and similarities concerning gas-induced alterations on different types of clusters are discussed. (author)

  1. First Light Curve Analyses of Binary Systems AO Aqr, CW Aqr and ASAS 012206-4924.7

    Ulas, Burak

    2015-01-01

    Using the data from the public database of the All Sky Automated Survey ({\\tt ASAS}) we performed the very first light curve analyses of the three eclipsing binary systems \\astrobj{AO~Aqr}, \\astrobj{CW~Aqr} and \\astrobj{ASAS~012206-4924.7}. The physical parameters of the systems were determined by the {\\tt PHOEBE} software. From an analysis of the ASAS data it was concluded that AO~Aqr was found to be a contact binary system while CW~Aqr and ASAS~012206-4924.7 were found to be near--contact and detached binaries, respectively. Finally, the locations of the components, corresponding to the estimated physical parameters, in the HR diagram were also discussed.

  2. A vacuum tolerant high voltage system with a low noise and low power Cockcroft–Walton photomultiplier base

    We developed a high voltage system for the electromagnetic calorimeter of the KOTO detector. The system is designed around a low noise, low power Cockcroft–Walton (CW) photomultiplier tube base with a high gain preamplifier. The low power makes it suitable for operations in vacuum. The low noise and high gain allow detecting signals in the 1 MeV range. We achieved a final noise level below 180μVrms for a preamplifier gain of more than 40. A vacuum tolerant control system for the CW bases power distribution was also designed. This system is able to control and monitor the high voltage of each individual base

  3. A vacuum tolerant high voltage system with a low noise and low power Cockcroft–Walton photomultiplier base

    Masuda, T., E-mail: taka@scphys.kyoto-u.ac.jp [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Iwai, E. [Department of Physics, Osaka University, Osaka 560-0043 (Japan); Kawasaki, N. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Kim, E.J. [Division of Science Education, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Komatsubara, T.K. [High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Lee, J.W. [Department of Physics, Osaka University, Osaka 560-0043 (Japan); Lim, G.Y. [High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Maeda, Y.; Naito, D.; Nanjo, H. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Nomura, T. [High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Ri, Y.D. [Department of Physics, Osaka University, Osaka 560-0043 (Japan); Sasao, N. [Research Core for Extreme Quantum World, Okayama University, Tsushima-naka 3-1-1 Kita-ku, Okayama 700-8530 (Japan); Sato, K. [Department of Physics, Osaka University, Osaka 560-0043 (Japan); Seki, S. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Shiomi, K.; Sugiyama, Y.; Togawa, M. [Department of Physics, Osaka University, Osaka 560-0043 (Japan); Watanabe, H. [High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Yamanaka, T. [Department of Physics, Osaka University, Osaka 560-0043 (Japan)

    2014-05-11

    We developed a high voltage system for the electromagnetic calorimeter of the KOTO detector. The system is designed around a low noise, low power Cockcroft–Walton (CW) photomultiplier tube base with a high gain preamplifier. The low power makes it suitable for operations in vacuum. The low noise and high gain allow detecting signals in the 1 MeV range. We achieved a final noise level below 180μV{sub rms} for a preamplifier gain of more than 40. A vacuum tolerant control system for the CW bases power distribution was also designed. This system is able to control and monitor the high voltage of each individual base.

  4. In situ vehicle engine exhaust measurements of nitric oxide with a thermoelectrically cooled, cw DFB quantum cascade laser

    This paper describes the application of a thermoelectrically cooled, continuous wave (cw), single mode distributed feedback (DFB) quantum cascade laser (QCL) to the real-time, in situ vehicle engine exhaust monitoring of nitric oxide. Experiments have been carried out on a static gasoline engine test bed where the engine operating conditions can be varied in a controlled manner. Results show the response of the nitric oxide concentration to engine conditions. The prospects for further multispecies in situ measurements are discussed.

  5. In situ vehicle engine exhaust measurements of nitric oxide with a thermoelectrically cooled, cw DFB quantum cascade laser

    Kasyutich, V L; Holdsworth, R J [TDL Sensors Ltd., CTF, 46 Grafton St., Manchester (United Kingdom); Martin, P A, E-mail: philip.martin@manchester.ac.u

    2009-03-01

    This paper describes the application of a thermoelectrically cooled, continuous wave (cw), single mode distributed feedback (DFB) quantum cascade laser (QCL) to the real-time, in situ vehicle engine exhaust monitoring of nitric oxide. Experiments have been carried out on a static gasoline engine test bed where the engine operating conditions can be varied in a controlled manner. Results show the response of the nitric oxide concentration to engine conditions. The prospects for further multispecies in situ measurements are discussed.

  6. High-Temperature Monitoring of Refractory Wall Recession Using Frequency-Modulated Continuous-wave (FM-CW) Radar Techniques

    Furnaces are among the most crucial components in the glass and metallurgical industry. Nowadays, furnaces are being operated at higher temperatures and for longer periods of time thus increasing the rate of wear on the furnace refractory lining. Consequently, there is a great need for a nondestructive tool that can accurately measure refractory wall thickness at high temperatures. In this paper the utility of a frequency-modulated continuous-wave (FM-CW) radar is investigated for this purpose

  7. Frequency-Modulated Continuous-Wave Fm-Cw Radar for Evaluation of Refractory Structures Used in Glass Manufacturing Furnaces

    Carroll, B.; Kharkovsky, S.; Zoughi, R.; Limmer, R.

    2009-03-01

    A frequency-modulated continuous-wave (FM-CW) handheld radar operating in the frequency range of 8-18 GHz, resulting in a relatively fine range resolution was designed and constructed for on-site inspection of refractory structure thickness. This paper presents the design of the radar and the results of measurements conducted on typical refractory furnace structures assembled in the laboratory.

  8. Basics and first experiments demonstrating isolation improvements in the agile polarimetric FM-CW radar – PARSAX

    Krasnov, O.A.; Babur, G.P.; Wang, Z.; Ligthart, L.P.; Van der Zwan, F.

    2010-01-01

    The article describes the IRCTR PARSAX radar system, the S-band high-resolution Doppler polarimetric frequency modulated continuous wave (FM-CW) radar with dual-orthogonal sounding signals, which has the possibility to measure all elements of the radar target polarization scattering matrix simultaneously, in one sweep. The performance of such radar depends of the level of sounding signals orthogonality. In the main operational mode, the radar will be used for atmospheric remote sensing and po...

  9. Design studies of quasioptical launcher for a 170 GHz, 1.5 MW CW gyrotron for ITER project

    The first hand design of Quasi-optical launcher for 170 GHz, 1.5 MW CW gyrotron with TE36,10 is stated in present paper. The proposed launcher converts cavity mode (TE36,10) into free space TEM mode for easy transmission over transmission line. RF-output with 99.7% Gaussian fit profile is achieved with 99.9% energy conversion. Results support the bright, single Gaussian beam output from gyrotron. (author)

  10. Development of a 325 MHz high power klystron

    A new high power CW klystron has been developed for Chinese Accelerator Driven System. The klystron is horizontally-oriented and outputs 600-kW CW power at 325 MHz, designed on the basis of the 324-MHz, 3-MW, pulsed klystron E3740A. It mainly consists of a triode electron gun, a six-cavity interaction circuit, a coaxial window, an output waveguide equipped with a T-bar converter and a force-water-cooled collector. The RF interaction circuit is optimized to obtain efficiency more than 60% for the nominal output power. The collector is capable of handling up to 1.1 MW to work with non-RF condition. Stable operation with an output power of 614 kW and an efficiency of 62.2% was achieved in the test performed in May, 2013. (author)

  11. Update: Health Status of Iranian Victims of Chemical Weapons / Ongoing Research Projects Addressing CW Health Effects in Iran

    Use of chemical weapons against Iran during the 1980s was a horrifying epic in the annals of modern warfare, inflicting enormous suffering during the conflict that continues to the present day in the form of latent illness among survivors. Surviving victims suffer from a diverse range of chronic illnesses placing an enormous strain on the nation's medical infrastructure. To define the scope of this problem, the National Organization for Veteran's Affairs (Janbazan) established a subsidiary research department called Janbazan Medical and Engineering Research Center (JMERC). Beginning in 2000 JMERC has conducted epidemiological, clinical and basic scientific studies to characterize disease among chemical attack survivors and develop new therapeutic strategies. The primary JMERC mission has been to identify where resources may be allocated so as to most effectively treat patients with the greatest need - requiring a comprehensive picture of the major medical problems among this population. Accordingly, JMERC's initial task was to define the nature and distribution of serious chronic illness among CW survivors. Therefore epidemiological studies in CW-exposed Iranian populations are currently underway. Ultimately these studies will allow management of illness among CW-exposed populations that is both compassionate and cost-effective. A summary of the above mentioned research projects will be reported in this article. (author)

  12. Influence of annealing on the linear and nonlinear optical properties of Mn doped ZnO thin films examined by z-scan technique in CW regime

    Nagaraja, K. K.; Pramodini, S.; Poornesh, P.; Rao, Ashok; Nagaraja, H. S.

    2016-08-01

    We present the studies on the influence of annealing on the third-order nonlinear optical properties of RF magnetron sputtered manganese doped zinc oxide (MZO) thin films with different doping concentration. It is revealed that the incorporation of Mn into ZnO and annealing lead to prominent changes in the third order nonlinearity. Nonlinear optical measurements were carried out by employing the z-scan technique using a continuous wave (CW) Hesbnd Ne laser of 633 nm. The z-scan results reveal that the films exhibit self-defocusing thermal nonlinearity. The third-order nonlinear optical susceptibility χ(3) was found to be of the order of 10-3 esu and 10-2 esu for annealed MZO thin films at 200 °C and 400 °C respectively. The dependence of grain size on the observed nonlinearity was revealed by atomic force microscopy analysis. Optical limiting studies were carried out for a range of input power levels and an optical limiting of about ∼8 mW was observed indicating the possible application for photonic devices.

  13. Status Of The Novosibirsk High Power Free Electron Laser

    Bolotin, V P; Knyazev, B A; Kolobanov, E I; Kotenkov, V V; Kubarev, V V; Kulipanov, G N; Matveenko, A N; Medvedev, L E; Miginsky, S V; Mironenko, L A; Oreshkov, A D; Ovchar, V K; Popik, V M; Salikova, T V; Scheglov, M A; Serednyakov, S I; Shevchenko, O A; Skrinsky, A N; Vinokurov, N A; Zaigraeva, N S

    2004-01-01

    The first stage of Novosibirsk high power free electron laser (FEL) was commissioned in 2003. It is based on normal conducting CW energy recovery linac. Now the FEL provides electromagnetic radiation in the wavelength range 120-180 micron. The average power is 200 W. The measured linewidth is 0.3%, which is close to the Fourier-transform limit. The assembly of user beamline is in progress. Plans of future developments are discussed.

  14. High power-efficiency terahertz quantum cascade laser

    Li, Yuan-Yuan; Liu, Jun-Qi; Liu, Feng-Qi; Zhang, Jin-Chuan; Zhai, Shen-Qiang; Zhuo, Ning; Wang, Li-Jun; Liu, Shu-Man; Wang, Zhan-Guo

    2016-08-01

    We demonstrate continuous-wave (CW) high power-efficiency terahertz quantum cascade laser based on semi-insulating surface-plasmon waveguide with epitaxial-side down (Epi-down) mounting process. The performance of the device is analyzed in detail. The laser emits at a frequency of ∼ 3.27 THz and has a maximum CW operating temperature of ∼ 70 K. The peak output powers are 177 mW in pulsed mode and 149 mW in CW mode at 10 K for 130-μm-wide Epi-down mounted lasers. The record wall-plug efficiencies in direct measurement are 2.26% and 2.05% in pulsed and CW mode, respectively. Project supported by the National Basic Research Program of China (Grant Nos. 2014CB339803 and 2013CB632801), the Special-funded Program on National Key Scientific Instruments and Equipment Development, China (Grant No. 2011YQ13001802-04), and the National Natural Science Foundation of China (Grant No. 61376051).

  15. Pi 2 Pulsations observed at the FM-CW Radar and MAGDAS station

    Ikeda, A.; Yumoto, K.; Uozumi, T.; Shinohara, M.; Nozaki, K.; Yoshikawa, A.; Bychkov, V.; Shevtsov, B.

    2009-12-01

    At the onset of magnetospheric substorms, Pi 2 pulsations occur globally in the magnetosphere with a period range from 40 to 150 seconds [e.g. Saito, 1968]. Pi 2 has been studied with arrays of magnetometers on the ground and with in-situ observation by satellites [e.g., Yumoto et al., 2001]. However, analysis of Pi 2 electric pulsations in the ionosphere is limited. In this study, we have focused on the phase relationship between the ionospheric Doppler velocity in the F-region detected by an FM-CW (Frequency Modulated Continuous Wave) radar and the magnetic Pi 2 pulsations observed by MAGDAS (the MAGnetic Data Acquisition System) [Yumoto and the MAGDAS Group, 2006 and 2007] at station PTK (Magnetic Latitude: 45.8 degree, Magnetic Longitude: 221.6 degree, L=2.05). During Sep., 2006 to Nov., 2007, we found about 100 Pi 2 events which (1) show high correlation coefficient between the Doppler Velocity (V) and magnetic H component (H), and (2) whose dominant frequency of V and H is the same in the local midnight sector (18-06 LT). The phase delay between V and H depends on LT and shows almost -90 degree in the local time sector of 21-06 LT By assuming that the V is owing to the eastward pulsation electric field (Ey), the phase relation of -90 degree can be explained by the radial standing wave, i.e., cavity mode oscillation suggested by Takahashi et al. [JGR, 2001]. On the other hand, Pi 2 pulsations may arise from a different mechanism in other local time sectors.

  16. Diode end-pumped 1123-nm Nd:YAG laser with 2.6-W output power

    Zhiqiang Cai; Meng Chen; Zhigang Zhang; Rui Zhou; Wuqi Wen; Xin Ding; Jianquan Yao

    2005-01-01

    We present a compact and high output power diode end-pumped Nd:YAG laser which operates at the wavelength of 1123 nm. Continuous wave (CW) laser output of 2.6 W was achieved at the incident pump power of 15.9 W, indicating an overall optical-optical conversion efficiency of 16.4%, and the slope efficiency was 18%.

  17. High power Nd:YAG spinning disk laser.

    Ongstad, Andrew P; Guy, Matthew; Chavez, Joeseph R

    2016-01-11

    We report on a high power Nd:YAG spinning disk laser. The eight cm diameter disk generated 200 W CW output with 323 W of absorbed pump in a near diffraction-limited beam. The power conversion efficiency was 64%. The pulsed result, 5 ms pulses at 10 Hz PRF, was nearly identical to the CW result indicating good thermal management. Rotated at 1200-1800 RPM with He impingement cooling the disk temperature increased by only 17 °C reaching a maximum temperature of ~31 °C. The thermal dissipation per unit of output power was 0.61 watt of heat generated per watt of laser output, which is below the typical range of 0.8-1.1 for 808 nm diode pumped Nd:YAG lasers. PMID:26832242

  18. EC power sources: European technological developments towards ITER

    The activities in Europe towards the development of the EC power sources for ITER are centered on the development of a 170 GHz, 2 MW, CW coaxial cavity gyrotron of collector potential depressed (CPD) type. A gyrotron with a higher unit power than the ITER reference (1 MW) would yield a reduction of the installation costs, a more compact launcher design and, if required, an increase of the power delivered through one port. Tests proving the principle were successfully performed on a short-pulse experimental gyrotron delivering up to 2.2 MW in single mode. Following this success, a coordinated and fully consistent programme of development has been launched. The first industrial 2 MW prototype is now at an advanced stage of construction. The associated superconductive magnet producing 6.86 T on the cavity axis is also being procured. Dummy loads suitable for short and CW operation are also part of the development effort. Finally, a new EC test facility, with the features necessary for the testing of the gyrotron up to full power in CW, has been established and includes a fully solid-state power supply system

  19. Association study on HLA-Cw*0602 allele in patients with psoriasis vulgaris in Han nationality of Henan Province%河南地区汉族人银屑病与HLA-Cw*0602等位基因的关联研究

    朱明明; 张晓菲; 高敏

    2012-01-01

    Objective; To associate HLA- Cw*0602 allele with genetic susceptibility to psoriasis vulgaris (PV) in Han of Henan province. Method: Using high- resolution polymerase chain reaction amplification with sequence specific primers ( PCR - SSP), the frequencies of HLA - Cw * 0602 allele were detected among 200 patients with PV and 200 healthy controls in Henan, and the correlation of HLA - Cw * 0602 allele to family history with PV' was analyzed. Results: HLA - Cw * 0602 allelic frequency increased in patients with PV compared with control group (72% vs 24% , P = 0.000), with no difference between male and female. The onset of the disease among the patients carrying HLA- Cw*0602 allele was earlier than those without carrying HLA-Cw* 0602 allele (80.2% vs 28.6% , P = 0.001). There was no significant difference in family history between the patients with HLA- Cw* 0602 allele and the patients without HLA - Cw * 0602 allele (P = 1.000). Conclusion: HLA - Cw * 0602 allele is highly associated with genetic susceptibility to PV in the Han of Henan and the carriers of HLA - Cw * 0602 allele are more likely to develop early - onset psoriasis. The frequency of HLA - Cw * 0602 allele is not associated with family history in PV.%目的:分析河南地区汉族人银屑病与HLA-Cw*0602等位基因的相关性.方法:运用聚合酶链反应-序列特异性引物(PCR-SSP)法检测河南地区汉族人200例寻常型银屑病患者和200名健康对照的HLA-Cw*0602等位基因频率,并分析携带该基因的银屑病患者与家族史的关系.结果:病例组HLA-Cw*0602等位基因频率较对照组显著升高(73%vs24%,P=0.000),但无性别差异;携带HLA-Cw*0602等位基因的银屑病患者发病年龄早于不具有该等位基因的患者(80.2%vs28.6%,P=O.001);有银屑病家族史患者携带HLA-Cw*0602等位基因的频率与无银屑病家族史者差异无显著性(P=1.000).结论:HLA-Cw*0602等位基因与河南地区汉族人银屑病易感性高度关

  20. A vacuum tolerant high voltage system with a low noise and low power Cockcroft–Walton photomultiplier base

    Masuda, T.; Iwai, E.; Kawasaki, N; Kim, E. J.; Komatsubara, T. K.; Lee, J.W.; Lim, G. Y.; Maeda, Y.; Naito, D.; Nanjo, H.; Nomura, T.; Ri, Y. D.; Sasao, N.; Sato, K.; Seki, S.

    2014-01-01

    We developed a high voltage system for the electromagnetic calorimeter of the KOTO detector. The system is designed around a low noise, low power Cockcroft–Walton (CW) photomultiplier tube base with a high gain preamplifier. The low power makes it suitable for operations in vacuum. The low noise and high gain allow detecting signals in the 1 MeV range. We achieved a final noise level below 180 μV[rms] for a preamplifier gain of more than 40. A vacuum tolerant control system for the CW bases p...

  1. Underwater laser welding by 4 kW CW YAG laser

    In May 2000 JSME issued Rules on fitness-for-service for nuclear power plants, which define allowable flaw sizes at operating nuclear power plants, and based on evaluation against these rules, rational repairs were to be realized. According to results, rational in-situ repairs were urgently needed on aged nuclear power plants, and since underwater laser repairs met utilities requirements, the authors developed underwater YAG laser repair technology. Hitachi installed the equipment at JAPEIC (Japan Power Engineering and Inspection Corporation) in 1998 and implemented 0.3 MPa underwater YAG laser welding in both downward and horizontal direction repairs, even in a U groove work piece. Metallurgical studies are ongoing. (author)

  2. High power, high frequency helix TWT's

    Sloley, H. J.; Willard, J.; Paatz, S. R.; Keat, M. J.

    The design and performance characteristics of a 34-GHz pulse tube capable of 75 W peak power output at 30 percent duty cycle and a broadband CW tube are presented. Particular attention is given to the engineering problems encountered during the development of the tubes, including the suppression of backward wave oscillation, the design of electron guns for small-diameter high-current beams, and the thermal capability of small helix structures. The discussion also covers the effects of various design parameters and choice of engineering materials on the ultimate practical limit of power and gain at the operating frequencies. Measurements are presented for advanced experimental tubes.

  3. High power and spectral purity continuous-wave photonic THz source tunable from 1 to 4.5 THz for nonlinear molecular spectroscopy

    Kiessling, J.; Breunig, I.; Schunemann, P. G.; Buse, K.; Vodopyanov, K. L.

    2013-10-01

    We report a diffraction-limited photonic terahertz (THz) source with linewidth Yb:YAG disc laser at 1030 nm. We take advantage of the enhancement of both optical fields inside a high-finesse OPO cavity: with 10 W of 1030 nm pump, 100 W of intracavity power near 2 μm was attained with GaAs inside cavity. This allows dramatic improvement in terms of generated THz power, as compared to the state-of-the art CW methods. We achieved >25 μW of single-frequency tunable CW THz output power scalable to >1 mW with proper choice of pump laser wavelength.

  4. An investigation of the thermal cycling damage of 25 vol. pct SiCw/alumina ceramic matrix composite

    Armstrong, William D.; Taya, Minoru

    1989-01-01

    An investigation was made of the thermal cycling damage of a 25 vol pct SiC whisker/alumina (SiCw/Al2O3) composite. Thermal cycling tests were conducted by subjecting a composite specimen to two different fluidized beds. After thermal cycling the composite specimens were subjected to elastic modulus and effective fracture toughness measurements. The thermal cycled specimens were investigated with SEM and TEM studies. It was found that this composite has a relatively high resistance to thermal cycling.

  5. FM-CW Radar Observation of the Electric Fields Penetrating into the Low Latitude Ionosphere at the Time of SC

    Ikeda, A.; Shinohara, M.; Yoshikawa, A.; Nozaki, K.; Yumoto, K.

    2006-12-01

    When SC(geomagnetic sudden commencement) occurs, the intensity of the geomagnetic field increases rapidly in low latitude region. In addition, PI(preliminary impulse) and following MI(main impulse) electric field penetrate into the polar ionosphere from the magnetosphere[Tamao,1964 ; Araki,1994], and propagate to the low latitude ionosphere instantly [Kikuchi et al.,1978 ; Kikuchi and Araki,1979]. In order to detect ionospheric electric fields, we have built an FM-CW radar(HF radar) in Sasaguri, Fukuoka (geomagnetic latitude=23.2 degree, geomagnetic longitude=199.6 degree). FM-CW radar observation started in 2002 using a doppler mode. Using this mode, we can observe short period(few seconds) phenomenon caused by penetration of electric field from the magnetosphere to the ionosphere. By using the FM-CW radar at 10 s sampling, we can measure the vertical drift velocity v of the ionosphere and its altitude. The IGRF model is used to estimate magneticfield B at Sasaguri. The ionospheric electric field E is derived by the relational expression of E=-v*B. Using the above method, we estimated the intensity of ionospheric electric field at the time of SC. For example, intensity of PI electric field was 0.16 mV/m (westward) and MI was 0.69 mV/m (eastward) in dayside at Nov.4, 2003. In the case of nightside, PI was 0.23mV/m (eastward) and MI was 1.01 mV/m (westward) at Jan.21, 2005. In this study, using data from the FM-CW radar and SYM-H(H component of the midlatitude symmetric disturbance index), we plotted the intensity of the electric field versus the magnetic field intensity at the time of SC (MI). There is a positive correlation between the intensity of the MI electric field and SC amplitude. Further we examined the magnetic local time(MLT) dependence of the intensity of the electric field at the time of MI. In addition, we will compare the intensity of the MI electric field and solar wind parameters at the time of SC.

  6. Tokamak ion temperature determination via CW far-infrared laser scattering from externally excited ion Bernstein waves

    The paper describes a successful proof-of-principle experimental determination of tokamak ion temperature using cw far-infrared (FIR) collective laser scattering from externally excited ion Bernstein waves. It is shown that a viable wave excitation technique for tokamak plasmas is mode conversion of an externally launched fast Alfven wave. A fit of the experimentally determined ion Bernstein wave dispersion to the temperature-dependent theoretical dispersion yields the local ion temperature. Partial ion temperature profiles (chord-averaged) have been obtained with temperature values consistent with charge-exchange measurements. (author)

  7. Multi-Watt, diffraction-limited CW and Q-switched, diode-end-pumped, double-clad waveguide lasers

    Mackenzie, J.I.; Wang, J.; Shepherd, D

    2003-01-01

    We demonstrate that double-clad waveguides can be used to obtain multiWatt, CW and Q-switched, diffraction-limited output when end-pumped by broad-stripe diodes. The waveguide geometry is shown to be especially favourable for efficient laser operation of low gain and quasithree-level transitions. The performance of the Nd:YAG system at several operating wavelengths. The quasithree-level 946 nm performance appears particularly impressive. The passively Q-switched Yb:YAG double-clad waveguide l...

  8. Development of a 2 MW CW Waterload for Electron Cyclotron Heating Systems

    R. Lawrence,Ives; Maxwell Mizuhara; George Collins; Jeffrey Neilson; Philipp Borchard

    2012-11-09

    Calabazas Creek Research, Inc. developed a load capable of continuously dissipating 2 MW of RF power from gyrotrons. The input uses HE11 corrugated waveguide and a rotating launcher to uniformly disperse the power over the lossy surfaces in the load. This builds on experience with a previous load designed to dissipate 1 MW of continuous RF power. The 2 MW load uses more advanced RF dispersion to double the capability in the same size device as the 1 MW load. The new load reduces reflected power from the load to significantly less than 1 %. This eliminates requirements for a preload to capture reflected power. The program updated control electronics that provides all required interlocks for operation and measurement of peak and average power. The program developed two version of the load. The initial version used primarily anodized aluminum to reduce weight and cost. The second version used copper and stainless steel to meet specifications for the ITER reactor currently under construction in France. Tests of the new load at the Japanese Atomic Energy Agency confirmed operation of the load to a power level of 1 MW, which is the highest power currently available for testing the load. Additional tests will be performed at General Atomics in spring 2013. The U.S. ITER organization will test the copper/stainless steel version of the load in December 2012 or early in 2013. Both loads are currently being marketed worldwide.

  9. High-power single-transverse-mode ridge optical waveguide semiconductor lasers

    Popovichev, VV; Davydova, EI; Marmalyuk, AA; Simakov, A; Uspenskii, MB; Chel'nyi, AA; Bogatov, AP; Drakin, AE; Plisyuk, SA; Sratonnikov, AA

    2002-01-01

    More than 200 mW of a single-transverse-mode cw output power is obtained from a semiconductor heterolaser by optimising the waveguide properties of its ridge structure. e laser-beam divergence is close to the diffraction limit and its brightness exceeds 5 x 10(7) W cm(-2) sr(-1). The calculated and

  10. Development of high power lasers and their applications for nuclear engineering in IHI

    High power laser technologies developed in IHI are summarized. A discharge-excited CO laser of 3 kW and an arc lamp pumped cw YAG laser of 3 kW with a flexible optical fiber delivery have been developed for material processing use. An ablation processing using a high intensity pulse laser has also been investigated. (author)

  11. Diode-pumped continuous-wave and femtosecond Cr:LiCAF lasers with high average power in the near infrared, visible and near ultraviolet.

    Demirbas, Umit; Baali, Ilyes; Acar, Durmus Alp Emre; Leitenstorfer, Alfred

    2015-04-01

    We demonstrate continuous-wave (cw), cw frequency-doubled, cw mode-locked and Q-switched mode-locked operation of multimode diode-pumped Cr:LiCAF lasers with record average powers. Up to 2.54 W of cw output is obtained around 805 nm at an absorbed pump power of 5.5 W. Using intracavity frequency doubling with a BBO crystal, 0.9 W are generated around 402 nm, corresponding to an optical-to-optical conversion efficiency of 12%. With an intracavity birefringent tuning plate, the fundamental and frequency-doubled laser output is tuned continuously in a broad wavelength range from 745 nm to 885 nm and from 375 to 440 nm, respectively. A saturable Bragg reflector is used to initiate and sustain mode locking. In the cw mode-locked regime, the Cr:LiCAF laser produces 105-fs long pulses near 810 nm with an average power of 0.75 W. The repetition rate is 96.4 MHz, resulting in pulse energies of 7.7 nJ and peak powers of 65 kW. In Q-switched mode-locked operation, pulses with energies above 150 nJ are generated. PMID:25968727

  12. High power and high temperature continuous-wave operation of distributed Bragg reflector quantum cascade lasers

    Xie, Feng, E-mail: xief@corning.com; Caneau, Catherine G.; LeBlanc, Herve P.; Ho, Ming-tsung; Wang, Jie; Chaparala, Satish; Hughes, Lawrence C.; Zah, Chung-en [Corning Incorporated, Corning, New York 14831 (United States)

    2014-02-17

    High temperature continuous-wave (CW) operation of a distributed Bragg reflector (DBR) quantum cascade laser is demonstrated up to a heat sink temperature of 80 °C. A CW output power of 2 W and a single mode operation with side mode suppression ratio of 30 dB around wavelength of 4.48 μm were achieved at 20 °C. The maximum pulsed and CW wall-plug-efficiencies reached 14.7% and 10.3% at 20 °C, respectively. A large tuning range of 5 cm{sup −1} between mode hopping was observed and attributed to the thermal cross-talk from the gain section to the DBR section.

  13. Initial RF measurements of the CW normal-conducting RF injector

    Krawczyk, Frank L [Los Alamos National Laboratory; Moody, Nathan A [Los Alamos National Laboratory; Martinez, Felix A [Los Alamos National Laboratory; Nguyen, Dinh C [Los Alamos National Laboratory; Bolme, Gerald [Los Alamos National Laboratory; Young, Karen [Los Alamos National Laboratory; Toung, Lloyd [AES

    2008-09-08

    The LANL 2.5-cell, normal-conducting radio-frequency (NCRF) injector has been fabricated. We present initial results of low-power RF measurements (cavity Q, cavity field map, coupling beta, etc.) of the NCRF injector. The measured cavity Q and relative fields are found to be in good agreement with the design calculations and earlier measurements of Glidcop properties. However, the coupling beta of the ridge-loaded waveguides is found to be significantly higher than the design point. The impact of these low-power measurement results on the planned high-power RF and electron beam tests will be discussed.

  14. Noise performance of frequency- and phase-locked CW magnetrons operated as current-controlled oscillators.

    Tahir, I.; Dexter, A.; Carter, Richard G.

    2005-01-01

    Low-power continuous wave ``cooker'' magnetrons driven from industrial-quality switch-mode power supplies have been frequency locked by driving them as current-controlled oscillators in a phase-lock loop (PLL). The noise performance of these frequency-locked oscillators is reported as a function of heater power. The injection of -30- to -40-dB signals derived from the reference oscillator of the PLL into the magnetron's output waveguide while the anode current is controlled by the PLL is show...

  15. Pulsed vs. CW low level light therapy on osteoarticular signs and symptoms in limited scleroderma (CREST syndrome)

    Barolet, Daniel

    2012-03-01

    Limited cutaneous systemic sclerosis (lcSSc) was formerly known as CREST syndrome in reference to the associated clinical features: Calcinosis, Raynaud's phenomenon, Esophageal dysfunction, Sclerodactyly, and Telangiectasias. The transforming growth factor beta (TGF-β) has been identified has a major player in the pathogenic process, while low level light therapy (LLLT) has been shown to modulate this cytokine superfamily. This case study was conducted to assess the efficacy of 940nm using microsecond domain pulsing and continuous wave mode (CW) on osteoarticular signs and symptoms associated with lcSSc. The patient was treated two to three times a week for 13 weeks, using a sequential pulsing mode on one elbow, and a CW mode on the other. Efficacy assessments included inflammation, symptoms, pain, and health scales, patient satisfaction, clinical global impression, and adverse effects monitoring. Significant functional and morphologic improvements were observed after LLLT, with best results seen with the pulsing mode. No significant adverse effects were noted. Two mechanisms of action may be at play. The 940nm wavelength provides inside-out heating possibly vasodilating capillaries which in turn increases catabolic processes leading to a reduction of in situ calcinosis. LLLT may also improve symptoms by triggering a cascade of cellular reactions, including the modulation of inflammatory mediators.

  16. The Deep Space Network's X/X/Ka Feed: Modifications for 100 kW CW Uplink Operation

    Hoppe, Daniel J.; Khayatian, Behrouz; Sosnowski, John B.

    2010-01-01

    The Deep Space Network, which provides communication services for NASA's robotic missions, consists of a number of 34m beam waveguide antennas and conventional 70m dual-reflector antennas located around the globe, [1]. The 34m beam waveguide antennas employ a three-band feed covering the deep space uplink band near 7.2 GHz, and downlink bands at 8.45 and 32 GHz. Simultaneous uplink commanding at 25 kW CW and ultra low noise reception in both bands is supported along with monopulse tracking at 32 GHz, [2]. An existing uplink capability of 25 kW is also available on the 70m antennas using a more conventional X/X diplexing feed. In order to provide an equivalent uplink capability with the 34m antennas the X/X/Ka feed is currently being modified for 100 kW CW operation, [3]. Here we will discuss both the existing feed and the 100 kW modifications which are underway.

  17. Locations of radical species in black pepper seeds investigated by CW EPR and 9 GHz EPR imaging

    Nakagawa, Kouichi; Epel, Boris

    2014-10-01

    In this study, noninvasive 9 GHz electron paramagnetic resonance (EPR)-imaging and continuous wave (CW) EPR were used to investigate the locations of paramagnetic species in black pepper seeds without further irradiation. First, lithium phthalocyanine (LiPC) phantom was used to examine 9 GHz EPR imaging capabilities. The 9 GHz EPR-imager easily resolved the LiPC samples at a distance of ∼2 mm. Then, commercially available black pepper seeds were measured. We observed signatures from three different radical species, which were assigned to stable organic radicals, Fe3+, and Mn2+ complexes. In addition, no EPR spectral change in the seed was observed after it was submerged in distilled H2O for 1 h. The EPR and spectral-spatial EPR imaging results suggested that the three paramagnetic species were mostly located at the seed surface. Fewer radicals were found inside the seed. We demonstrated that the CW EPR and 9 GHz EPR imaging were useful for the determination of the spatial distribution of paramagnetic species in various seeds.

  18. Night-side DP-2 type fluctuations observed by the FM-CW Radar and MAGDAS stations

    Ikeda, A.; Yumoto, K.; Uozumi, T.; Abe, S.; Shinohara, M.; Nozaki, K.; Yoshikawa, A.; Bychkov, V.; Shevtsov, B.; Sugon, Q.; McNamara, D.

    2010-12-01

    DP-2 type fluctuations caused by IMF southward/northward variations have important information about how the solar wind effects are transferred into the magnetosphere, ionosphere, and on the ground. Since dayside ground magnetic field variations are significantly enhanced during DP-2 events, dayside DP-2 fluctuations have been investigated for many years. However night-side DP-2 variations are not yet investigated sufficiently. In this study, we examined night-side magnetic and electric field variations when DP-2 was observed in dayside. Ground data from MAGDAS/CPMN (MAGnetic Data Acqisition System and Circum-pan Pacific Magnetometer Network) stations were analyzed. We also investigated the association of DP-2 with the ionospheric electric fields obtained by the FM-CW (Frequency Modulated Continuous Wave) radar at PTK (M.Lat. = 45.8 degree, M.Lon.= 221.6 degree) and solar wind parameters from the ACE satellite. The amplitudes of night-side DP-2 on 11 Oct., 2008 became greater with increasing of the latitude of 210 MM stations. While there were no Pi 2 pulsations, and signatures of substorms were not detected with the DP 2. At the time, westward electric field was observed by the FM-CW radar in the night-side sector simultaneously with the positive variation of night-side ground magnetic fields. Therefore the night-side DP-2 magnetic fluctuation is found not to be caused by the ionospheric currents.

  19. Effect of cw-CO2 laser surface treatment on structure and properties of AZ91 magnesium alloy

    Iwaszko, Józef; Strzelecka, Monika

    2016-06-01

    In the study, samples of AZ91 magnesium alloy were subjected to a surface remelting treatment by means of a continuous wave (cw) CO2 laser. The scope of the investigation included both macro- and microstructural examination, hardness measurements, and wear resistance tests. The investigation has shown that remelting treatment leads to a strong refinement of structure in the surface layer and a more even distribution of phases. Fine α-phase dendrites have been observed to dominate in the remelting zone. The dendritic arm spacing in the laser treated surface was in the range of 1-2.5 μm. The structural changes triggered by remelting have contributed to an increase in the hardness and the wear resistance of AZ91 alloy. The microhardness of the remelted zone has increased to 71-93 HV0.05 for single-strip remelting and to 84-107 HV0.05 for multi-strip remelting in comparison with about ~60 HV0.05 for untreated alloy. The friction coefficient has decreased from 0.375 for material w/o treatment to 0.311 for remelted material. SEM investigations of samples after tribological tests have revealed the presence of parallel grooves proving the occurrence of microploughing and micro cutting of the material during the tribological testing. The results of the conducted investigation have indicated a beneficial influence of the cw-CO2 laser remelting treatment on the structure and properties of AZ91 alloy.

  20. High-power 1550 nm tapered DBR lasers fabricated using soft UV-nano-imprint lithography

    Viheriälä, Jukka; Aho, Antti T.; Mäkelä, Jaakko; Salmi, Joel; Virtanen, Heikki; Leinonen, Tomi; Dumitrescu, Mihail; Guina, Mircea

    2016-03-01

    Paper reports the DBR-RWG surface grating design, the fabrication process, and the output characteristics of tapered DBR laser diodes for the applications, like for example LIDAR and range finding, that require eye-safe high-power single-mode coherent light sources. The fabricated regrowth-free DBR AlGaInAs/InP lasers exhibited a CW output power as high as 560 mW in single-mode operation at room temperature. At maximum output power the SMSR was 38 dB, proving the excellent behavior of the surface gratings. The tapered section enabled scaling the maximum CW power at room temperature from 125 mW to 560 mW, by increasing its length from 0.5 mm to 4.0 mm. The paper discusses the limitations and performance variation associated to the power scaling by using the tapered section length as a scaling parameter.

  1. Fabrication of the high power input coupler for BEPCⅡ superconducting cavities

    2008-01-01

    The BEPCII storage ring adopts two 500 MHz superconducting cavities (SCC). Each one is equipped with a 500 MHz input power coupler. The coupler is to feed 150 kW power in continuous wave (CW) mode with both standing and traveling wave modes. Due to high power feeding and high frequency of the coupler, its fabrication is a big challenge. The fabrication started with two key components, the window and the antenna. Up to now, two sets including windows and antennas have beam made by IHEP. And a 270 kW RF power in CW has passed through the coupler during the high power test. The fabrication details are presented in this paper.

  2. Frequency and phase modulation performance of an injection-locked CW magnetron.

    Tahir, I.; Dexter, A.; Carter, Richard G.

    2006-01-01

    It is demonstrated that the output of a 2.45-GHz magnetron operated as a current-controlled oscillator through its pushing characteristic can lock to injection signals in times of the order of 100-500 ns depending on injection power, magnetron heater power, load impedance, and frequency offset of the injection frequency from the natural frequency of the magnetron. Accordingly, the magnetron can follow frequency and phase modulations of the injection signal, behaving as a narrow-band amplifier...

  3. HLA-B51 and haplotypic diversity of B-Cw associations: implications for matching in unrelated hematopoietic stem cell transplantation.

    Bettens, F; Nicoloso de Faveri, G; Tiercy, J-M

    2009-04-01

    In unrelated hematopoietic stem cell transplantation (HSCT), human leukocyte antigen (HLA)-C locus incompatibilities occur frequently and are associated with increased risk of posttransplant complications. Because HLA-B51 is associated with a high rate of Cw disparities, we performed a comprehensive four-digit typing analysis of 140 ABCDRB1 B51 genotypes proven by pedigree analysis and 311 unrelated donors selected for 75 B51-positive patients. In addition, 145 A1/Ax-B8/B51-DR3/DRx donors were HLA typed at a high-resolution level and tested for three microsatellite (Msat) polymorphisms located in the HLA class I and III regions. Based on these data sets, 182 different ABCDR haplotypes with 14 different B-Cw associations were detected. Rates of Cw mismatches were shown to be highly correlated with the ABDRB1 haplotypes. We have computed 21 B51 haplotypes that disclose a high probability of HLA-C allele matching and 30 haplotypes with a low (HLA-C allele frequency profiles were quite different in these two groups, with a more heterogeneous distribution in the low matching probability group. HLA-Cw*1502 was inversely correlated with the likelihood to identify a Cw-mismatched donor: it was present in 61% of the high vs 18% of the low probability group (P A1-B8-DR3 haplotype. HLA-B51 haplotypes therefore exhibit a high diversity at the level of B-Cw associations and of non-HLA polymorphisms in the class I and III regions. Such heterogeneity negatively impacts on overall matching in HSCT. PMID:19317740

  4. High-level expression and characterization of two chitinases, ChiCH and ChiCW, of Bacillus cereus 28-9 in Escherichia coli

    Many chitinase genes have been cloned and sequenced from prokaryotes and eukaryotes but overexpression of chitinases in Escherichia coli cells was less reported. ChiCH and ChiCW of Bacillus cereus 28-9 belong to two distinct groups based on their amino acid sequences of catalytic domains, and in addition, domain structures of two enzymes are different. In this study, we established an ideal method for high-level expression of chitinases in E. coli as glutathione-S-transferase fusion proteins using pGEX-6P-1 vector. Both ChiCH and ChiCW were successfully highly expressed in E. coli cells as soluble GST-chitinase fusion proteins, and recombinant native ChiCH and ChiCW could be purified after cleavage with PreScission protease to remove GST tag. Purified chitinases were used for biochemical characterization of kinetics, hydrolysis products, and binding activities. The results indicate that ChiCW is an endo-chitinase and effectively hydrolyzes chitin and chito-multimers to chito-oligomers and the end product chitobiose, and ChiCH is an exo-chitinase and degrades chito-oligomers to produce chitobiose. Furthermore, due to higher affinity of ChiCW toward colloidal chitin than Avicel, C-terminal domain of ChiCW should be classified as a chitin-binding domain not a cellulose-binding domain although that was revealed as a cellulose-binding domain by conserved domain analysis. Therefore, the method of high-level expression of chitinases is helpful to studies and applications of chitinases

  5. Fatigue Strength and Modal Analysis of CW-200K Bogie Frame%CW-200K转向架构架疲劳强度及模态分析研究

    吴丹; 郭富强; 商跃进; 王红

    2011-01-01

    Based on the structure and load characteristics of CW-200K bogie frame, the solid model is built by using Solidworks according to the structural parameters of CW-200K bogie frame. According to the analytical results, the fatigue strength of the frame is checked referring to JIS E 4207 and Goodman sketch for welding materials. In addition, the modal analysis of the frame is made and the vibrational modal of frame in given frequency-domain is predetermined to evaluate the dynamical behavior of the frame in order to meet the dynamical design requirements. Analyzed with the simulation results, the test stress values are lower than standard values and the frame meets the requirement of fatigue strength. The lower self-vibration frequency of the frame is 33. 944Hz which can avoid excited frequency of the frame. The optimization in structural behavior of the frame is provided with theoretical parameters.%根据CW-200K转向架构架的结构和承载特点,运用Solidworks建立构架的实体模型,并将模型导入ANSYS中进行有限元分析,依据分析结果并参照标准JIS E4207-2004和焊接材料的Goodman疲劳极限图对构架进行疲劳强度评估.此外,还对构架进行模态分析,分析构架在某一频域内的振动模态,从而评价构架的动态性能是否满足设计要求.分析结果表明:各关键点的等效应力均小于许用值,构架满足疲劳强度的要求;构架的最低自振频率为33.944 Hz,能够有效地避开激振频率.这为优化构架结构提供相关的参数依据.

  6. Detection of some stable species during the oxidation of methane by coupling a jet-stirred reactor (JSR) to cw-CRDS

    Bahrini, Chiheb; Herbinet, Olivier; Glaude, Pierre-Alexandre; Schoemaecker, Coralie; Fittschen, Christa; Battin-Leclerc, Frédérique

    2012-05-01

    We present the coupling of a jet-stirred reactor to detection by cw-CRDS in the near infrared and first results obtained during the oxidation of methane. The mixture is rapidly expanded from the jet-stirred reactor into a 80 cm-long cw-CRDS cell maintained at a the pressure around 1.33 kPa, thus freezing the reaction and decreasing pressure broadening of the absorption lines. Some stable species (CH4, H2O and CH2O) have been quantified through their well structured spectra around 1506 nm, while H2O2 and HO2 radicals could not be detected.

  7. Detection of some stable species during the oxidation of methane by coupling a jet-stirred reactor (JSR) to cw-CRDS

    Bahrini, Chiheb; Herbinet, Olivier; Glaude, Pierre-Alexandre; Schoemaecker, Coralie; Fittschen, Christa; Battin-Leclerc, Frédérique

    2012-01-01

    We present the coupling of a jet-stirred reactor to detection by cw-CRDS in the near infrared and first results obtained during the oxidation of methane. The mixture is rapidly expanded from the jet-stirred reactor into a 80 cm-long cw-CRDS cell maintained at a the pressure around 1.33 kPa, thus freezing the reaction and decreasing pressure broadening of the absorption lines. Some stable species (CH4, H2O and CH2O) have been quantified through their well structured spectra around 1506 nm, whi...

  8. Development of High Power Vacuum Tubes for Accelerators and Plasma Heating

    High pulsed power magnetrons and klystrons for medical and industrial accelerators, and high CW power klystrons and gyrotrons for plasma heating in tokamak, are being developed at CEERI. S-band 2.0MW pulsed tunable magnetrons of centre frequency 2856MHz and 2998 MHz were developed, and S-band 2.6MW pulsed tunable magnetron is being developed for medical LINAC, and 3MW pulsed tunable magnetron is being developed for industrial accelerator. S-band (2856MHz), 5MW pulsed klystron was developed for particle accelerator, and S-band 6MW pulsed klystron is under development for 10MeV industrial accelerator. 350MHz, 100kW (CW) klystron is being developed for proton accelerator, and C-band 250kW (CW) klystron is being developed for plasma heating. 42GHz, 200kW (CW/Long pulse) gyrotron is under development for plasma heating. Plasma filled tubes are also being developed for switching. 25kV/1kA and 40kV/3kA thyratrons were developed for high voltage high current switching in pulse modulators for magnetrons and klystrons. 25kV/3kA Pseudospark switch of current rise time of 1kA/|a-sec and pulse repetition rate of 500Hz is being developed. Plasma assisted high power microwave device is also being investigated.

  9. Development of High Power Vacuum Tubes for Accelerators and Plasma Heating

    Srivastava, Vishnu

    2012-11-01

    High pulsed power magnetrons and klystrons for medical and industrial accelerators, and high CW power klystrons and gyrotrons for plasma heating in tokamak, are being developed at CEERI. S-band 2.0MW pulsed tunable magnetrons of centre frequency 2856MHz and 2998 MHz were developed, and S-band 2.6MW pulsed tunable magnetron is being developed for medical LINAC, and 3MW pulsed tunable magnetron is being developed for industrial accelerator. S-band (2856MHz), 5MW pulsed klystron was developed for particle accelerator, and S-band 6MW pulsed klystron is under development for 10MeV industrial accelerator. 350MHz, 100kW (CW) klystron is being developed for proton accelerator, and C-band 250kW (CW) klystron is being developed for plasma heating. 42GHz, 200kW (CW/Long pulse) gyrotron is under development for plasma heating. Plasma filled tubes are also being developed for switching. 25kV/1kA and 40kV/3kA thyratrons were developed for high voltage high current switching in pulse modulators for magnetrons and klystrons. 25kV/3kA Pseudospark switch of current rise time of 1kA/|a-sec and pulse repetition rate of 500Hz is being developed. Plasma assisted high power microwave device is also being investigated.

  10. Power Control and Data Acquisition System for High Power Microwave Test Bench

    The 6 MW/4.6 GHz lower hybrid current drive (LHCD) system will be set up on the experimental advanced superconducting tokamak (EAST) for achieving a steady-state operation. The high power and continuous wave (CW) mode microwave test bench operating at 250 kW/4.6 GHz has already been finished, which can be used to simulate different kinds of high power microwave environments to test microwave components and units for the new LHCD system. The power control and data acquisition system on the test bench composed of power control, high reflected power protection and data acquisition function is described here in detail. Long-term operation of the test bench showed that the power control and data acquisition system is very stable and reliable. (fusion engineering)

  11. CW and passively Q-switched double-clad planar waveguide lasers

    Beach, R.J.; Mitchell, S. C.; Meissner, H.E.; Meissner, O.R.; Krupke, W.F.; McMahon, J.M.; Bennett, W.J.; Mackenzie, J.I.; Bhutta, T.; Shepherd, D.P.

    2001-01-01

    Greater than 12 W of average output power have been generated from a diode pumped Yb:YAG cladding-pumped planar waveguide laser. The developed laser radiation is linearly polarized and diffraction limited in the guiding dimension. A slope efficiency of 0.5 W/W with a peak optical-optical conversion efficiency of 0.31 W/W is achieved. In a related structure, greater than 8 W of Q-switched average output power has been generated from a Nd:YAG cladding-pumped planar waveguide incorporating Cr:YA...

  12. Development program for a 200 kW, cw gyrotron. Final report

    Development of a millimeter-wave device to produce 200 kW of continuous wave power at 60 GHz is described. The device, a gyrotron oscillator, is intended for electron-cyclotron heating of fusion plasmas. The design philosophy is herein discussed and experimental results, both diagnostic and long pulse, are given

  13. A method of laser micro-polishing for metallic surface using UV nano-second pulse and CW lasers

    Jang, Pong-Ryol; Ji, Kum-Hyok; Kim, Nam-Chol

    2014-01-01

    During laser micro-polishing, the constant control of laser energy density is a key technology to improve the surface roughness. In this paper, a method which controls the energy density of UV(ultraviolet) pulse laser in real time with the control of CW(continuous wave) laser spot size in laser micro-polishing for metallic surface was presented. The experimental and analytical considerations of several influence factors such as laser spot size, fusion zone and focal offset were investigated. In addition, using a laser micro-polishing system manufactured with this method, the laser micro-polishing experiments on the two different surface shapes of stainless steel 316L were conducted. For the inclined or curved surface, the surface roughness improvements of up to 56.4% and 57.3% were respectively obtained, and the analysis of the results were discussed.

  14. Preliminary design study and problem definition for intense CW superconducting deuteron ion linac for fusion material study

    The advantages of superconducting (SC) cavity have been verified for many electron accelerators and the application of SC cavity to high intensity CW ion linacs is currently being considered. These linacs have been required for neutron irradiation tests of materials, transmutation of nuclear waste and so on. An SC linac consisting of SC cavities, SC quadrupole magnets and cryostats, was preliminarily designed to investigate the feasibility of applying to deuteron machine. Beam dynamics analysis was also carried out by using a modified PARMILA code in order to confirm no beam loss. Since radiation damage of superconductors is especially severe for such a machine, data relating to the damage were surveyed and discussed. Moreover, other major facilities such as cryogenic system, radio frequency amplifier and RF control system were considered. Many problems to be solved were defined but no critical issues were found. In consequence, it became clear that SC linac is very attractive and competitive with a room-temperature linac. (orig.)

  15. Data processing in a FM-CW radar system for ionospheric drift measurements by means of partial reflections

    Hoffmann, P.; Keuer, D.; Singer, W.; Linow, Th.

    The determination of the horizontal component of the ionospheric wind at the height range of 60-90 km is carried out by the spaced antenna drift method. The FM-CW radar system installed at Juliusruh (54.6 N; 13.4 E) is working with a center frequency of 3.18 MHz and permits a height resolution of 1.5km. During each measuring cycle 16 adjacent height channels are processed. Due to the large amount of primary data as well as a high resolution in time of wind values the data processing including the derivation of wind profiles must be carried out at real-time conditions. A resolution in time of 5 min is intended.

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

    Robert Rimmer, Frank Marhauser

    2009-05-01

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

  17. AIR FLOW AND ENVIRONMENTAL WIND VISUALIZATION USING A CW DIODE PUMPED FREQUENCY DOUBLED Nd:YAG Laser

    Mircea UDREA

    2009-09-01

    Full Text Available Preliminary results obtained in developing a visualisation technique for non-invasive analysis of air flow inside INCAS subsonic wind tunnel and its appendages are presented. The visualisation technique is based on using a green light sheet generated by a continuous wave (cw longitudinally diode pumped and frequency doubled Nd:YAG laser. The output laser beam is expanded on one direction and collimated on rectangular direction. The system is tailored to the requirements of qualitative analysis and vortex tracking requirements inside the INCAS 2.5m x 2.0m subsonic wind tunnel test section, for measurements performed on aircraft models. Also the developed laser techniques is used for non-invasive air flow field analysis into environmental facilities settling room (air flow calming area. Quantitative analysis is enabled using special image processing tools upon movies and pictures obtained during the experiments. The basic experimental layout in the wind tunnel takes advantage of information obtained from the investigation of various aircraft models using the developed visualisation technique. These results are further developed using a Particle Imaging Velocimetry (PIV experimental technique.The focus is on visualisation techniques to be used for wind flow characterization at different altitudes in indus-trial and civil buildings areas using a light sheet generated by a Nd:YAG cw pumped and doubled laser at 532 nm wave-length. The results are important for prevention of biological/chemical disasters such as spreading of extremely toxic pol-lutants due to wind. Numerical simulations of wind flow and experimental visualisation results are compared. A good agreement between these results is observed.

  18. Efficient High Power Ho,Tm:GdVO4 Laser

    WANG Yue-Zhu; ZHU Guo-Li; JU You-Lun; YAO Bao-Quan

    2011-01-01

    We report a 22.3 W cw diode-pumped cryogenic Ho(0.5at. %), Tm(at.5%):GdVC>4 laser at a wavelength of 2.05 fzm. It is pumped by two fiber-coupled laser diodes with a fiber core diameter of 0.4 mm, both of which provide 42 W pump power near 802 nm. A cw output power of 22.3 W was obtained at the pump power of 51.0 W, corresponding to an optical-to-optical conversion efficiency of 43.7% when the ratio of the pump beam to oscillating laser beam in the crystal was ^1.33:1. The M2 factor was found to be 2.0 under an output power of 16.5 W.%@@ We report a 22.3 W ew diode-pumped cryogenic Ho(0.5at.%),Tm(at.5%):GdVO4 laser at a wavelength of 2.05μm.It is pumped by two fiber-coupled laser diodes with a fiber core diameter of 0.4 mm,both of which provide 42W pump power near 802 nm.A cw output power of 22.3 W was obtained at the pump power of 51.0W,corresponding to an optical-to-optical conversion efficiency of 43.7%when the ratio of the pump beam to oscillating laser beam in the crystal was ~1.33:1.The M2 factor was found to be 2.0 under an output power of 16.5 W.

  19. Contrast enhancement and phase conjugation low-power optical signal in dynamic recording material based on bacteriorhodopsin

    Korchemskaya, Elena Y.; Soskin, Marat S.; Dukova, Tatjana V.; Vsevolodov, Nicolai N.

    1994-02-01

    Polymer films with fragments of the purple membranes containing protein bacteriorhodopsin (BR) have been used for the real-time optical information processing of low-power (several milliwatt) cw gas laser signals. The nonlinear recording media with BR have a potential in microscopic techniques for in-vivo diagnosis of the crystalline lens.

  20. Design and development of collector for C-band 250 kW CW Klystron

    The paper presents the design and development of collector for C-band 250 kW high power klystron. The design criteria for the collector assembly is selection of material, vacuum and high temperature compatibility, proper electron beam dispersion, minimum back scattering of electrons and thermal design for proper cooling at high power dissipation. All these aspects have been discussed for collector development in details. The collector has been designed in TRAK and then beam propagation has been analyzed in MAGIC 2D software. The thermal simulation has been done using ANSYS 11.0 (multi-physics). The outer surface of the collector has been grooved to facilitate its proper cooling. Design results are presented for water cooling with different flow rates and channel dimensions. OFHC copper material is chosen for collector which is suitable for vacuum and hydrogen brazing operations and good thermal properties for efficient cooling.

  1. Performance improvement of 100 kW high frequency transmitter for CW operation

    For the plasma heating of KSTAR(Korea Superconducting Tokamak Advanced Research)by using ICH(Ion Cyclotron Heating), it is designed that the selective ion heating and current drive are performed by the transmitter with the rf power of 8 MW in the frequency range of 25-60 MHz. 100 kW HF transmitter was constructed for the high voltage/current test of ICH antenna and HF transmission components. The output power is about 100 kW around 30 MHz. Thomson 581 tetrode is used for the final amplifier whose cavity type is ground cathode. Overall gain is above 15 dB and the bandwidth is about 100 kHz

  2. Optical phase locking of two infrared CW lasers separated by 100 THz

    Chiodo, Nicola; Hrabina, Jan; Lours, Michel; Chea, Erick; Acef, Ouali

    2014-01-01

    We report on phase-locking of two continuous wave infrared laser sources separated by 100 THz emitting around 1029 nm and 1544 nm respectively. Our approach uses three independent harmonic generation processes of the IR laser frequencies in periodically poled MgO: LiNbO3 crystals to generate second and third harmonic of that two IR sources. The beat note between the two independent green radiations generated around 515 nm is used to phase-lock one IR laser to the other, with tunable radio frequency offset. In this way, the whole setup operates as a mini frequency comb (MFC) emitting four intense optical radiations (1544 nm, 1029 nm, 772 nm and 515 nm), with output powers at least 3 orders of magnitude higher than the available power from each mode emitted by femtosecond lasers.

  3. Design and fabrication of broad angular range depth-graded C/W multilayer mirror for hard X-ray optics

    Zhong Zhang; Zhanshan Wang; Fengli Wang; Wenjuan Wu; Hongchang Wang; Shuji Qin; Lingyan Chen

    2005-01-01

    @@ In this paper, a depth-graded C/W multilayer mirror with broad grazing incident angular range, consisting of three multilayer stacks, each of which has different period thickness d and the layer pair number,was designed and fabricated by direct current (DC) magnetron sputtering.

  4. Effect of corn steep liquor (CSL) and cassava wastewater (CW) on chitin and chitosan production by Cunninghamella elegans and their physicochemical characteristics and cytotoxicity.

    Berger, Lúcia Raquel Ramos; Stamford, Thayza Christina Montenegro; Stamford-Arnaud, Thatiana Montenegro; de Oliveira Franco, Luciana; do Nascimento, Aline Elesbão; Cavalcante, Horacinna M de M; Macedo, Rui Oliveira; de Campos-Takaki, Galba Maria

    2014-01-01

    Microbiological processes were used for chitin and chitosan production with Cunninghamella elegans UCP/WFCC 0542 grown in different concentrations of two agro-industrial wastes, corn steep liquor (CSL) and cassava wastewater (CW) established using a 2² full factorial design. The polysaccharides were extracted by alkali-acid treatment and characterized by infrared spectroscopy, viscosity, thermal analysis, elemental analysis, scanning electron microscopy and X-ray diffraction. The cytotoxicity of chitosan was evaluated for signs of vascular change on the chorioallantoic membrane of chicken eggs. The highest biomass (9.93 g/L) was obtained in trial 3 (5% CW, 8% CSL), the greatest chitin and chitosan yields were 89.39 mg/g and 57.82 mg/g, respectively, and both were obtained in trial 2 (10% CW, 4% CSL). Chitin and chitosan showed a degree of deacetylation of 40.98% and 88.24%, and a crystalline index of 35.80% and 23.82%, respectively, and chitosan showed low molecular weight (LMW 5.2 × 10³ Da). Chitin and chitosan can be considered non-irritating, due to the fact they do not promote vascular change. It was demonstrated that CSL and CW are effective renewable agroindustrial alternative substrates for the production of chitin and chitosan. PMID:24590203

  5. High-effective denitrification of low C/N wastewater by combined constructed wetland and biofilm-electrode reactor (CW-BER).

    He, Yuan; Wang, Yuhui; Song, Xinshan

    2016-03-01

    The low denitrification effect on constructed wetlands (CWs) treating low carbon to nitrogen ratio (C/N) wastewater was a problem. In this study, a novel coupled system by installing CW and biofilm-electrode reactor (CW-BER) was developed. In this system, the heterotrophic and autotrophic denitrifying bacteria all played their roles in denitrification process. The system was investigated systematically with simulated wastewater at different C/Ns, electric current intensities (I), hydraulic retention times (HRTs), and pH. Results showed that the optimum running conditions were C/N=0.75-1, I=15 mA, HRT=12 h, and pH=7.5. The highest removal efficiency of NO3-N and TN at the best conditions was respectively 63.03% and 98.11% for CW-BER. Also, the TN and NO3-N enhancive removal efficiency of CW-BER was 23.26% and 24.20%, respectively. No residual organic carbon source was detected in final effluent at the best parameters. PMID:26735879

  6. Demonstration of frequency control and CW diode laser injection control of a titanium-doped sapphire ring laser with no internal optical elements

    Bair, Clayton H.; Brockman, Philip; Hess, Robert V.; Modlin, Edward A.

    1988-01-01

    Theoretical and experimental frequency narrowing studies of a Ti:sapphire ring laser with no intracavity optical elements are reported. Frequency narrowing has been achieved using a birefringent filter between a partially reflecting reverse wave suppressor mirror and the ring cavity output mirror. Results of CW diode laser injection seeding are reported.

  7. Effect of Corn Steep Liquor (CSL and Cassava Wastewater (CW on Chitin and Chitosan Production by Cunninghamella elegans and Their Physicochemical Characteristics and Cytotoxicity

    Lúcia Raquel Ramos Berger

    2014-02-01

    Full Text Available Microbiological processes were used for chitin and chitosan production with Cunninghamella elegans UCP/WFCC 0542 grown in different concentrations of two agro-industrial wastes, corn steep liquor (CSL and cassava wastewater (CW established using a 22 full factorial design. The polysaccharides were extracted by alkali-acid treatment and characterized by infrared spectroscopy, viscosity, thermal analysis, elemental analysis, scanning electron microscopy and X-ray diffraction. The cytotoxicity of chitosan was evaluated for signs of vascular change on the chorioallantoic membrane of chicken eggs. The highest biomass (9.93 g/L was obtained in trial 3 (5% CW, 8% CSL, the greatest chitin and chitosan yields were 89.39 mg/g and 57.82 mg/g, respectively, and both were obtained in trial 2 (10% CW, 4% CSL. Chitin and chitosan showed a degree of deacetylation of 40.98% and 88.24%, and a crystalline index of 35.80% and 23.82%, respectively, and chitosan showed low molecular weight (LMW 5.2 × 103 Da. Chitin and chitosan can be considered non-irritating, due to the fact they do not promote vascular change. It was demonstrated that CSL and CW are effective renewable agroindustrial alternative substrates for the production of chitin and chitosan.

  8. Rewriting of low electrical resistance lines on TiO2 film by writing and erasing with femtosecond and CW fiber lasers

    Highlights: • A rewriting process on TiO2 film was developed with femtosecond and CW fiber lasers. • Low electrical resistance lines are written on TiO2 film with a femtosecond laser. • Low electrical resistance lines are erased on TiO2 film with a CW fiber laser. • Low electrical resistance lines can be rewritten with a femtosecond laser. - Abstract: A rewriting process was developed for reduced electrical resistance lines on a titanium dioxide (TiO2) film with femtosecond and CW fiber lasers. In this process, lines are written on TiO2 film by femtosecond laser irradiation, where the lines have a lower electrical resistance than the surrounding film. By heating with a CW fiber laser in air, the low electrical resistance lines are erased and their electrical resistances increase. When the erased areas on the TiO2 film are irradiated with the femtosecond laser, the lower electrical resistance lines can be rewritten on the film surface

  9. Space power by ground-based laser transmission

    Landis, Geoffrey A.

    1992-01-01

    A new method for providing power to space vehicles consists of using high-power CW lasers on the ground to beam power to photovoltaic receivers in space. Such large lasers could be located at cloud-free sites at one or more ground locations, and use large mirrors with adaptive optical correction to reduce the beam spread due to diffraction or atmospheric turbulence. This can result in lower requirements for battery storage, due to continuous illumination of arrays even during periods of shadow by the earth, and higher power output, due to the higher efficiency of photovoltaic arrays under laser illumination compared to solar and the ability to achieve higher intensities of illumination. Applications include providing power for satellites during eclipse, providing power to resurrect satellites which are failing due to solar array degradation, powering orbital transfer vehicles or lunar transfer shuttles, and providing night power to a solar array on the moon.

  10. Administrative Court of Munich, judgement of June 26, 1985 (security of nuclear power plants)

    The decision of the Administrative Court of Munich is dealing with the protection of the nuclear power station of Isar I in Ohu. The use of shotguns for the protection of objects and persons ouside of private properties is a danger for public security. Consequently shotguns are not qualified for the protection of nuclear power stations (sec. 7 para. 2 No. 5 of the Atomic Energy Act). (CW)

  11. High-Power Testing of the APT Power Coupler

    Schmierer, E N; Gautier, D C; Gioia, J G; Haynes, W B; Krawczyk, F L; Madrid, M A; Schrage, D L; Waynert, J A; Rusnak, B

    2000-01-01

    For the baseline APT (Accelerator Production of Tritium) linac design, power couplers are required to transmit 210-kW of CW RF power to the superconducting cavities. These APT couplers operate at 700 MHz, have a coaxial design and an adjustable coupling to the superconducting cavities. Since May 1999, we have been testing couplers of this design on a room-temperature test stand. We completed tests at transmitted-power and reflected-power conditions up to 1 MW. We also tested the couplers with a portion of the outer conductor cooled by liquid nitrogen. Under this latter condition, we studied the effects of condensed gases on coupler performance. The results of these tests indicate that the APT couplers are capable of delivering more than 500 kW to the cavities. We are in the process of increasing the baseline coupler design requirement to 420 kW of transmitted power to take advantage of this successful development. In this paper, we describe the results of our high-power coupler tests.

  12. Drivers for High Power Laser Diodes

    Yankov P; Todorov D; Saramov E

    2006-01-01

    During the last year the high power laser diodes jumped over the 1 kW level of CW power for a stack,and the commercial 1 cm bars reached 100 W output optical power at the standard wavelengths around 800 nm and 980 nm. The prices are reaching the industry acceptable levels. All Nd:YAG and fiber industrial lasers manufacturers have developed kW prototypes. Those achievements have set new requirements for the power supplies manufactuers-high and stable output current, and possibilities for fast control of the driving current, keeping safe the expensive laser diode. The fast switching frequencies also allow long range free space communications and optical range finding. The high frequencies allow the design of a 3D laser radar with high resolution and other military applications. The prospects for direct laser diode micro machining are also attractive.

  13. Use of the 2-μm cw laser as addition and/or alternative for the Nd:YAG in urology

    de Boorder, Tjeerd; Verdaasdonk, Rudolf; Lock, Tycho; Grimbergen, Matthijs; Klaessens, John

    2007-02-01

    Recently, 2 μm cw laser systems have been introduced for surgery. The 2 μm wavelength is predominantly absorbed by water and enables effective cutting and ablation of tissue similar to the cw CO II laser. In contrast to the CO II laser, the 2 μm wavelength is delivered through fiber optics and available for endoscopic procedures. After many years of experience with the 1.06 μm Nd:YAG laser, we started to use the 2 μm cw laser as alternative for various urological treatments. The treatments strategies and optimal settings were examined in the lab comparing the two 1.06 and 2 μm wavelengths performing thermal measurements. Consequently, the laser was applied for various urological cases. Penile tumors were resected with haemostatic effects and good aesthetic healing comparable with the Nd:YAG laser. Although the Nd:YAG has initially a deeper penetration, the blackening of the fiber during tissue cutting, provides a more superficial effect like the 2 μm laser. Bladder (pre)malignancies were ablated after biopsy. Only with higher stage tumors, coagulation depth of the Nd:YAG might be preferable for adequate treatment. Strictures in the urethra were incised and stents were effectively desobstructed: one patient with a stent implanted after a pelvic trauma, and one patient with catheterizable apedico stoma stenoses. The thermal damage during incision to deeper layers is minimal so recurrence due to scarring is not expected. Also hair grow in patients who underwent urethroplasty was effectively treated and scrotal atheromata cysts were effectively resected without recurrence. Laparoscopic nefrectomies are being considered using the 2 μm cw laser. The 2 μm cw laser has shown to be a versatile instrument for effective treatment of various urological indications. More patients and long term results are needed to prove the clinical significance compared to other treatment modalities

  14. Beam shaping concepts for kW-class CW and QCW diode lasers

    Unger, Andreas; Fassbender, Willhelm; Müntz, Holger; Köhler, Bernd; Biesenbach, Jens

    2016-03-01

    In modern diode lasers beam shaping of the highly asymmetric laser beam, which exits the front facet of the semiconductor laser material, is a crucial step towards cost efficient high brightness laser modules which in turn can be further combined towards kW-class diode lasers and can be efficiently fiber coupled. In order to scale up the power of a single laser module in an economic way, high fill factor laser bars are employed. The increased power density from such a laser bar requires improved cooling technologies. On the other hand the increased fill factor of the bar makes advanced beam shaping necessary to be able to achieve small focal spot sizes and couple the laser module efficiently into optical fibers. Finally, to be able to mass produce the laser modules, it is desirable to design the module in a way that allows automated packaging and optics alignment. In this talk, the beam shaping concepts developed at DILAS for high fill factor bars are presented. Starting from optical simulation and choice of optical elements the laser modules incorporating these bars are presented. The concepts developed enable very compact laser modules of up to 2kW of power at a single wavelength with beam qualities of less than 40mm x mrad. Optionally these modules can be wavelength stabilized via external feedback. The packaging technology developed enables the automated alignment of the optics and cooling is DI-water free. Based on the same concepts very compact free space and fiber coupled QCW packages are presented as well.

  15. Improving Lifetime of Quasi-CW Laser Diode Arrays for Pumping 2-Micron Solid State Lasers

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

    2007-01-01

    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 on 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.

  16. Development of a CW NCRF Photoinjector using Solid Freeform Fabrication (SFF)

    A key issue for high average power, normal conducting radio frequency (NCRF), photoinjectors is efficient structure cooling. To that end, RadiaBeam has been developing the use of Solid Freeform Fabrication (SFF) for the production of NCRF photoinjectors. In this paper we describe the preliminary design, developed in collaboration with JLab, of a high gradient, very high duty cycle, photoinjector combining the cooling efficiency only possible through the use of SFF, and the RF efficiency of a re-entrant gun design. Simulations of the RF and thermal-stress performance are presented, as well as material testing of SFF components.

  17. Modeling of thermal lensing in cw end-pumped solid-state lasers

    Yu Jin; Meng Hongxiang; Jin Tianfeng [Chinese Academy of Sciences, Changchun (China). State Key Lab. of Applied Optics

    1996-12-31

    Thermal focusing acts as a key role in limiting and degrading the lasing performance in a continuously end-pumped solid-state laser. In order to evaluate the deleterious effect caused by thermal lensing in such a laser scheme, heat transfer equation is solved to obtain the temperature distribution in an edge-cooled and axially Gaussian beam heated rod in the form of a power series, taking into account only the radial heat flow, which is a reasonable simplification of the real situation. Also, under the two assumptions of thin disk and long rod, the induced stress- and strain-field are deduced, respectively. Thus the analytical expressions for the induced thermal focusing length are determined over the extent of axially average pump spot size, considering all the following three elements contributing to thermal focusing: thermal dispersion, surface deformation and stress-induced birefringence, and regarding the rod as thin lens and thick lens, respectively. The results are applied to cubic crystals, such as Nd:YAG and Nd:GSGG, and the homogenous medium of silicate Nd:glass. It can be seen that with ten watt of pump power, the effective focusing lengths of these materials are in the order of the millimeters and much more serious than those predicted by other authors.

  18. Modeling of thermal lensing in cw end-pumped solid state lasers

    Yu, Jin; Meng, Hongxiang; Jin, Tianfeng

    1996-09-01

    Thermal focusing acts as a key role in limiting and degrading the laser performance in a continuously end-pumped solid-state laser. In order to evaluate the deleterious effect caused by thermal lensing in such a laser scheme, heat transfer equation is solved to obtain the temperature distribution in an edge-cooled and axially Gaussian beam heated rod in the form of a power series, taking into account only the radial heat flow, which is a reasonable simplification of the real situation. Also, under the two assumptions of thin disk and long rod, the induced stress- and strain-field are deduced, respectively. Thus the analytical expressions for the induced thermal focusing length are determined over the extent of axially average pump spot size, considering all the following three elements contributing to thermal focusing: thermal dispersion, surface deformation and stress-induced birefringence, and regarding the rod as thin lens and thick lens, respectively. The results are applied to cubic crystals, such as Nd:YAG and Nd:GSGG, and the homogeneous medium of silicate Nd:glass. It can be seen that with ten watt of pump power, the effective focusing lengths of these materials are in the order of millimeters and much more serious than those predicted by other authors.

  19. Side-pumped Nd:YVO{sub 4} cw laser with grazing-incidence small angle configuration; Laser de Nd:YVO{sub 4} bombeado transversalmente em configuracao com angulo rasante interno

    Camargo, Fabiola de Almeida

    2006-07-01

    Within the existing variety of laser cavity geometries and gain materials there is one combination that is particularly interesting because of its reduced complexity and high efficiency: the edge-pumped slab-laser using grazing-incidence geometry and a gain media with a very high pump absorption cross-section. In this work we studied a diode side-pumped Nd:YVO{sub 4} cw laser. We describe a single and a multiple bounce laser configurations. We demonstrate 22 W of multimode output power for 35 watts of pump power with a single pass through the gain media. A high optical-to-optical conversion efficiency of 63% and a slope efficiency of 74% with a very compact and simple Nd:YVO{sub 4} cavity that uses joint stability zones was achieved. The beam quality was M{sup 2} = 26 x 11 in the horizontal and vertical direction, respectively. With a double pass configuration we achieved 17 watts with a better beam quality of M{sup 2} = 3,4 x 3,7, in the horizontal and vertical direction, respectively. (author)

  20. R&D ERL: High power RF systems

    Zaltsman, A.

    2010-01-15

    The Energy Recovery Linac (ERL) project, now under construction at Brookhaven National Laboratory, requires two high power RF systems. The first RF system is for the 703.75 MHz superconducting electron gun. The RF power from this system is used to drive nearly half an Ampere of beam current to 2.5 MeV. There is no provision to recover any of this energy so the minimum amplifier power is 1 MW. It consists of 1 MW CW klystron, transmitter and power supplies, 1 MW circulator, 1 MW dummy load and a two-way power splitter. The second RF system is for the 703.75 MHz superconducting cavity. The system accelerates the beam to 54.7 MeV and recovers this energy. It will provide up to 50 kW of CW RF power to the cavity. It consists of 50 kW transmitter, circulator, and dummy load. This paper describes the two high power RF systems and presents the test data for both.