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Sample records for ags rf system

  1. The upgrade project for the RF system for the Brookhaven AGS

    SciTech Connect

    Brennan, J.M.; Ciardullo, D.J.; Hayes, T.; Meth, M.; McNerney, A.J.; Otis, A.; Pirkl, W.; Sanders, R.; Spitz, R.; Toldo, F.; Zaltsman, A.

    1993-01-01

    The AGS operates a varied program of proton, heavy ion, and polarized proton acceleration for fixed-target experiments and will soon serve as the injector of these beams into the Relativistic Heavy Ion Collider, RHIC. The new Booster synchrotron extends the range of intensities and masses that can be accelerated. The 1.5 GeV injection energy increases the space charge limit by a factor of four to more than 6 [times] 10[sup 13] protons per pulse. To accommodate the increased beam current the rf system will be upgraded to provide more power and lower impedance to the beam. The flexibility of the rf system will also be enhanced by virtue of a new rf beam control system and installation of individual tuning servos for the ten rf cavities. The fundamental necessity for upgrading the rf system is to deliver more power to the accelerating beam. Three key ingredients of the upgrade project addressing this problem is (1) new power amplifiers provide the necessary power, and are closely coupled to the cavities, (2) wideband rf feedback reduces the effective impedance by a factor of 10, and (3) the capacitors loading the acceleration gaps (four per cavity) are increased from 275 pF to 600 pF.

  2. The upgrade project for the RF system for the Brookhaven AGS

    SciTech Connect

    Brennan, J.M.; Ciardullo, D.J.; Hayes, T.; Meth, M.; McNerney, A.J.; Otis, A.; Pirkl, W.; Sanders, R.; Spitz, R.; Toldo, F.; Zaltsman, A.

    1993-06-01

    The AGS operates a varied program of proton, heavy ion, and polarized proton acceleration for fixed-target experiments and will soon serve as the injector of these beams into the Relativistic Heavy Ion Collider, RHIC. The new Booster synchrotron extends the range of intensities and masses that can be accelerated. The 1.5 GeV injection energy increases the space charge limit by a factor of four to more than 6 {times} 10{sup 13} protons per pulse. To accommodate the increased beam current the rf system will be upgraded to provide more power and lower impedance to the beam. The flexibility of the rf system will also be enhanced by virtue of a new rf beam control system and installation of individual tuning servos for the ten rf cavities. The fundamental necessity for upgrading the rf system is to deliver more power to the accelerating beam. Three key ingredients of the upgrade project addressing this problem is (1) new power amplifiers provide the necessary power, and are closely coupled to the cavities, (2) wideband rf feedback reduces the effective impedance by a factor of 10, and (3) the capacitors loading the acceleration gaps (four per cavity) are increased from 275 pF to 600 pF.

  3. Rf beam control for the AGS Booster

    SciTech Connect

    Brennan, J.M.

    1994-09-26

    RF beam control systems for hadron synchrotrons have evolved over the past three decades into an essentially standard design. The key difference between hadron and lepton machines is the absence of radiation damping and existence of significant frequency variation in the case of hadrons. Although the motion of the hadron in the potential well of the rf wave is inherently stable it is not strongly damped. Damping must be provided by electronic feedback through the accelerating system. This feedback is typically called the phase loop. The technology of the rf beam control system for the AGS Booster synchrotron is described. First, the overall philosophy of the design is explained in terms of a conventional servo system that regulates the beam horizontal position in the vacuum chamber. The concept of beam transfer functions is fundamental to the mathematics of the design process and is reviewed. The beam transfer functions required for this design are derived from first principles. An overview of the beam signal pick-ups and high level rf equipment is given. The major subsystems, the frequency program, the heterodyne system, and beam feedback loops, are described in detail. Beyond accelerating the beam, the rf system must also synchronize the bunches in the Booster to the buckets in the AGS before transfer. The technical challenge in this process is heightened by the need to accomplish synchronization while the frequency is still changing. Details of the synchronization system are given. This report is intended to serve two purposes. One is to document the hardware and performance of the systems that have been built. The other is to serve as a tutorial vehicle from which the non-expert can not only learn the details of this system but also learn the principles of beam control that have led to the particular design choices made.

  4. Phase stable RF transport system

    DOEpatents

    Curtin, Michael T.; Natter, Eckard F.; Denney, Peter M.

    1992-01-01

    An RF transport system delivers a phase-stable RF signal to a load, such as an RF cavity of a charged particle accelerator. A circuit generates a calibration signal at an odd multiple frequency of the RF signal where the calibration signal is superimposed with the RF signal on a common cable that connects the RF signal with the load. Signal isolating diplexers are located at both the RF signal source end and load end of the common cable to enable the calibration to be inserted and extracted from the cable signals without any affect on the RF signal. Any phase shift in the calibration signal during traverse of the common cable is then functionally related to the phase shift in the RF signal. The calibration phase shift is used to control a phase shifter for the RF signal to maintain a stable RF signal at the load.

  5. Racetrack microtron rf system

    SciTech Connect

    Tallerico, P.J.; Keffeler, D.R.

    1985-01-01

    The rf system for the National Bureau of Standards (NBS)/Los Alamos cw racetrack microtron is described. The low-power portion consists of five 75-W amplifers that drive two input ports in each of two chopper deflection cavities and one port in the prebuncher cavity. A single 500-kW klystron drives four separate 2380-MHz cavity sections: the two main accelerator sections, a capture section, and a preaccelerator section. The phases and amplitudes in all cavities are controlled by electronic or electromechanical controls. The 1-MW klystron power supply and crowbar system were purchased as a unit; several modifications are described that improve power-supply performance. The entire rf system has been tested and shipped to the NBS, and the chopper-buncher system has been operated with beam at the NBS. 5 refs., 2 figs.

  6. The TESLA RF System

    NASA Astrophysics Data System (ADS)

    Choroba, S.

    2003-12-01

    The TESLA project proposed by the TESLA collaboration in 2001 is a 500 to 800GeV e+/e- linear collider with integrated free electron laser facility. The accelerator is based on superconducting cavity technology. Approximately 20000 superconducting cavities operated at 1.3GHz with a gradient of 23.4MV/m or 35MV/m will be required to achieve the energy of 500GeV or 800GeV respectively. For 500GeV ˜600 RF stations each generating 10MW of RF power at 1.3GHz at a pulse duration of 1.37ms and a repetition rate of 5 or 10Hz are required. The original TESLA design was modified in 2002 and now includes a dedicated 20GeV electron accelerator in a separate tunnel for free electron laser application. The TESLA XFEL will provide XFEL radiation of unprecedented peak brilliance and full transverse coherence in the wavelength range of 0.1 to 6.4nm at a pulse duration of 100fs. The technology of both accelerators, the TESLA linear collider and the XFEL, will be identical, however the number of superconducting cavities and RF stations for the XFEL will be reduced to 936 and 26 respectively. This paper describes the layout of the entire RF system of the TESLA linear collider and the TESLA XFEL and gives an overview of its various subsystems and components.

  7. Barrier rf systems in synchrotrons

    SciTech Connect

    Chandra M. Bhat

    2004-06-28

    Recently, many interesting applications of the barrier RF system in hadron synchrotrons have been realized. A remarkable example of this is the development of longitudinal momentum mining and implementation at the Fermilab Recycler for extraction of low emittance pbars for the Tevatron shots. At Fermilab, we have barrier RF systems in four different rings. In the case of Recycler Ring, all of the rf manipulations are carried out using a barrier RF system. Here, the author reviews various uses of barrier rf systems in particle accelerators including some new schemes for producing intense proton beam and possible new applications.

  8. RF system for ''TARN II''

    SciTech Connect

    Sato, K.; Fujita, M.; Itano, A.; Kanazawa, M.; Kodaira, M.; Kurihara, T.; Tojyo, E.; Watanabe, S.; Yamazaki, N.; Yoshizawa, M.

    1985-10-01

    An rf acceleration system for the INS heavy-ion synchrotron proposal is being developed. The rf characteristics of full-size ferrite toroids have been measured in a test cavity to study tunable frequencies of an rf cavity. It is estimated from the measurement on the ferrite material TDK SY-6 that a single-gap rf cavity based upon two ferrite-loaded quarter-wave coaxial resonators with four turns each of main and supplementary bias windings will give frequencies of 0.71-7.02 MHz for adiabatic capture and of 0.86-8.00 MHz for synchronous capture. RF acceleration parameters and design features of the rf cavity are presented.

  9. NSLS-II RF SYSTEMS

    SciTech Connect

    Rose, J.; Gash, W.; Holub, B.; Kawashima, Y.; Ma, H.; Towne, N.; Yeddulla, M.

    2011-03-28

    The NSLS-II is a new third generation light source being constructed at Brookhaven Lab. The storage ring is optimized for low emittance by use of damping wigglers to reduce the emittance to below 1 nm-rad. The RF systems are designed to provide stable beam through tight RF phase and amplitude stability requirements.

  10. RF deflector system for beamlines

    NASA Astrophysics Data System (ADS)

    Heikkinen, J.; Gustafsson, J.; Kivikoski, M.; Liukkonen, E.; Nieminen, V.

    1999-06-01

    In some in-beam experiments, an adjustment of the time structure of the cyclotron ion beam guided to the desired research target by a beamline is sometimes needed. This situation occurs if, for example, the decay times of the reaction products are too short compared to the period corresponding to the beam frequency. In the accelerator laboratory of the University of Jyväskylä the frequency of the ion pulses hitting the research target is 10-21 MHz depending on the frequency of the acceleration voltage. A RF deflector system was constructed to adjust the ion beam pulse frequency according to the respective requirements. A desired portion of the ion pulses are deflected by feeding a high-amplitude RF-signal between deflecting plates located into the beam line. The specified deflecting voltage amplitude of 10-15 kV is achieved with 1 kW of RF power.

  11. Rf System for the NLCTA

    SciTech Connect

    Wang, J.W.; Adolphsen, C.; Eichner, J.; Fuller, R.W.; Gold, S.L.; Hanna, S.M.; Hoag, H.A.; Holmes, S.G.; Koontz, R.F.; Lavine, Theodore L.; Loewen, R.J.; Miller, R.H.; Nantista, C.D.; Pope, R.; Rifkin, J.; Ruth, R.D.; Tantawi, S.G.; Vlieks, A.E.; Wilson, Z.; Yeremian, A.; /SLAC

    2011-08-26

    This paper describes an X-Band RF system for the Next Linear Collider Test Accelerator. The RF system consists of a 90 MeV injector and a 540 MeV linac. The main components of the injector are two low-Q single-cavity prebunchers and two 0.9-m-long detuned accelerator sections. The linac system consists of six 1.8-m-long detuned and damped detuned accelerator sections powered in pairs. The rf power generation, compression, delivery, distribution and measurement systems consist of klystrons, SLEDII energy compression systems, rectangular waveguides, magic-T's, and directional couplers. The phase and amplitude for each prebuncher is adjusted via a magic-T type phase shifter/attenuator. Correct phasing between the two 0.9 m accelerator sections is obtained by properly aligning the sections and adjusting two squeeze type phase shifters. Bunch phase and bunch length can be monitored with special microwave cavities and measurement systems. The design, fabrication, microwave measurement, calibration, and operation of the sub-systems and their components are briefly presented.

  12. Rf System for the NLCTA

    NASA Astrophysics Data System (ADS)

    Wang, J. W.; Adolphsen, C.; Eichner, J.; Fuller, R. W.; Gold, S. L.; Hanna, S. M.; Hoag, H. A.; Holmes, S. G.; Koontz, R. F.; Lavine, T. L.; Loewen, R. J.; Miller, R. H.; Nantista, C. D.; Pope, R.; Rifkin, J.; Ruth, R. D.; Tantawi, S. G.; Vlieks, A. E.; Wilson, Z.; Yeremian, A.

    1997-05-01

    This paper describes an X-Band rf system for the Next Linear Accelerator Test Accelerator. The rf system consists of a 90 MeV injector and a 540 MeV linac. The main components of the injector are two low-Q single-cavity prebunchers and two 0.9-m-long detuned accelerator sections. The linac system consists of six 1.8-m-long detuned, or damped and detuned, accelerator sections powered in pairs. The rf power generation, compression, delivery, distribution and measurement systems consist of klystrons, SLED-II energy compression systems, rectangular waveguides, magic-T's, and directional couplers. The phase and amplitude for each prebuncher is adjusted via a magic-T type phase shifter/attenuator. The correct phasing between two 0.9 m accelerator sections is obtained by properly setting the sections and adjusting two squeeze type phase shifters. Also, bunch phase and bunch length can be monitored by special microwave cavities and measurement systems. The design, fabrication, microwave measurement, calibration, and operation for above sub-systems and their components will be presented.

  13. Automatic calorimetry system monitors RF power

    NASA Technical Reports Server (NTRS)

    Harness, B. W.; Heiberger, E. C.

    1969-01-01

    Calorimetry system monitors the average power dissipated in a high power RF transmitter. Sensors measure the change in temperature and the flow rate of the coolant, while a multiplier computes the power dissipated in the RF load.

  14. Low jitter RF distribution system

    DOEpatents

    Wilcox, Russell; Doolittle, Lawrence; Huang, Gang

    2012-09-18

    A timing signal distribution system includes an optical frequency stabilized laser signal amplitude modulated at an rf frequency. A transmitter box transmits a first portion of the laser signal and receive a modified optical signal, and outputs a second portion of the laser signal and a portion of the modified optical signal. A first optical fiber carries the first laser signal portion and the modified optical signal, and a second optical fiber carries the second portion of the laser signal and the returned modified optical signal. A receiver box receives the first laser signal portion, shifts the frequency of the first laser signal portion outputs the modified optical signal, and outputs an electrical signal on the basis of the laser signal. A detector at the end of the second optical fiber outputs a signal based on the modified optical signal. An optical delay sensing circuit outputs a data signal based on the detected modified optical signal. An rf phase detect and correct signal circuit outputs a signal corresponding to a phase stabilized rf signal based on the data signal and the frequency received from the receiver box.

  15. Double rf system for bunch shortening

    SciTech Connect

    Chin, Yong Ho.

    1990-11-01

    It was suggested by Zisman that the combination of the two systems (double rf system) may be more effective to shorten a bunch, compromising between the desirable and the undesirable effects mentioned above. In this paper, we demonstrate that a double rf system is, in fact, quite effective in optimizing the rf performance. The parameters used are explained, and some handy formulae for bunch parameters are derived. We consider an example of bunch shortening by adding a higher-harmonic rf system to the main rf system. The parameters of the main rf system are unchanged. The double rf system, however, can be used for another purpose. Namely, the original bunch length can be obtained with a main rf voltage substantially lower than for a single rf system without necessitating a high-power source for the higher-harmonic cavities. Using a double rf system, the momentum acceptance remains large enough for ample beam lifetime. Moreover, the increase in nonlinearity of the rf waveform increases the synchrotron tune spread, which potentially helps a beam to be stabilized against longitudinal coupled-bunch instabilities. We will show some examples of this application. We discuss the choice of the higher-harmonic frequency.

  16. Overview of the RF Systems for LCLS

    SciTech Connect

    McIntosh, P.; Akre, R.; Boyce, R.; Emma, P.; Hill, A.; Rago, C.; /SLAC

    2005-06-15

    The Linac Coherent Light Source (LCLS) at SLAC, when it becomes operational in 2009, will provide its user community with an X-ray source many orders of magnitude brighter than anything available in the world at that time [1]. The electron beam acceleration will be provided by existing and new RF systems capable of maintaining the amplitude and phase stability of each bunch to extremely tight tolerances. RF feedback control of the various RF systems will be fundamental in ensuring the beam arrives at the LCLS undulator at precisely the required energy and peak current phase. This paper details the requirements for RF stability for the various LCLS RF systems and also highlights proposals for how these injector and Linac RF systems can meet these tight constraints.

  17. OPERATION OF THE RHIC RF SYSTEMS.

    SciTech Connect

    BRENNAN,J.M.; BLASKIEWICZ,M.; DELONG,J.; FISCHER,W.; HAYES,T.; SMITH,K.S.; ZALTSMAN,A.

    2003-05-12

    Operational aspects of the RHIC rf system are described. To date three different beam combinations have been collided for physics production: gold-gold, deuteron-gold, and proton-proton(polarized). To facilitate this flexibility the rf systems of the two rings are independent and self-sufficient. Techniques to cope with problems such as, injection/capture, beam loading, bunch shortening, and rf noise have evolved and are explained.

  18. RF SYSTEM FOR THE SNS ACCUMULATOR RING.

    SciTech Connect

    BLASKIEWICZ, M.; BRENNAN, J.M.; BRODOWSKI, J.; DELONG, J.; METH, M.; SMITH, K.; ZALTSMAN, A.

    2001-06-18

    During accumulation the RF beam current in the spallation neutron source ring rises from 0 to 50 amperes. A clean, 250 nanosecond gap is needed for the extraction kicker risetime. Large momentum spread and small peak current are needed to prevent instabilities and stopband related losses. A robust RF system meeting these requirements has been designed.

  19. Properties of nano structured Ag-TiO{sub 2} composite coating on stainless steel using RF sputtering method

    SciTech Connect

    Bakar, S. Abu; Jamuna-Thevi, K.; Abu, N.; Mohd Toff, M. R.

    2012-07-02

    RF Sputtering system is one of the Physical Vapour Deposition (PVD) methods that have been widely used to produce hard coating. This technique is used to deposit thin layers of metallic substrates such as stainless steel (SS). From this process, a good adhesiveness and wear resistance coating can be produced for biomedical applications. In this study, RF sputtering method was used to deposit TiO{sub 2}-Ag composite coatings via various deposition parameters. The parameters are RF power of 350W, gas composition (Ar: O{sub 2}) 50:5 and deposition time at 1, 2, 4 and 6 hours. Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Raman spectroscopy were used to characterize surface area of coated samples. The formation of nanocrystalline thin film and the surface morphology were examined using SEM. The crystallite size of TiO{sub 2}-Ag composite coatings were estimated between 20-60 nm based on XRD analysis using Scherer equation and SEM evaluation. The Raman and XRD results suggested that the structure of the TiO{sub 2}-Ag consist of anatase and rutile phases. It also showed that the intensity of anatase peaks increased after samples undergone annealing process at 500 Degree-Sign C.

  20. Single frequency RF powered ECG telemetry system

    NASA Technical Reports Server (NTRS)

    Ko, W. H.; Hynecek, J.; Homa, J.

    1979-01-01

    It has been demonstrated that a radio frequency magnetic field can be used to power implanted electronic circuitry for short range telemetry to replace batteries. A substantial reduction in implanted volume can be achieved by using only one RF tank circuit for receiving the RF power and transmitting the telemetered information. A single channel telemetry system of this type, using time sharing techniques, was developed and employed to transmit the ECG signal from Rhesus monkeys in primate chairs. The signal from the implant is received during the period when the RF powering radiation is interrupted. The ECG signal is carried by 20-microsec pulse position modulated pulses, referred to the trailing edge of the RF powering pulse. Satisfactory results have been obtained with this single frequency system. The concept and the design presented may be useful for short-range long-term implant telemetry systems.

  1. Multi-level RF identification system

    DOEpatents

    Steele, Kerry D.; Anderson, Gordon A.; Gilbert, Ronald W.

    2004-07-20

    A radio frequency identification system having a radio frequency transceiver for generating a continuous wave RF interrogation signal that impinges upon an RF identification tag. An oscillation circuit in the RF identification tag modulates the interrogation signal with a subcarrier of a predetermined frequency and modulates the frequency-modulated signal back to the transmitting interrogator. The interrogator recovers and analyzes the subcarrier signal and determines its frequency. The interrogator generates an output indicative of the frequency of the subcarrier frequency, thereby identifying the responding RFID tag as one of a "class" of RFID tags configured to respond with a subcarrier signal of a predetermined frequency.

  2. Design of RF Power System for CPHS

    NASA Astrophysics Data System (ADS)

    Cheng, Cheng; Du, Taibin; Guan, Xialing

    The Compact Pulsed Hadron Source (CPHS) system has been proposed and designed by the Department of Engineering Physics of Tsinghua University in Beijing, China. It consists of an accelerator front-end-a highintensity ion source, a 3 MeV radiofrequency quadrupole linac (RFQ), and a 13 MeV drift-tube linac (DTL), a neutron target station, and some experimental stations. In design of our RF power supply, both RFQ and DTL share a single klystron which is capable of 2.5 MW peak RF power and a 3.33% duty factor. The 325 MHz klystron contains a modulating anode and has a 100 kW average output power. Portions of the RF power system, such as pulsed high voltage power supply, modulator, crowbar protection and RF power transmission are all presented in details in this paper.

  3. The CEBAF RF Separator System Upgrade

    SciTech Connect

    J. Hovater; Mark Augustine; Al Guerra; Richard Nelson; Robert Terrell; Mark Wissmann

    2004-08-01

    The CEBAF accelerator uses RF deflecting cavities operating at the third sub-harmonic (499 MHz) of the accelerating frequency (1497 MHz) to ''kick'' the electron beam to the experimental halls. The cavities operate in a TEM dipole mode incorporating mode enhancing rods to increase the cavity's transverse shunt impedance [1]. As the accelerators energy has increased from 4 GeV to 6 GeV the RF system, specifically the 1 kW solid-state amplifiers, have become problematic, operating in saturation because of the increased beam energy demands. Two years ago we began a study to look into replacement for the RF amplifiers and decided to use a commercial broadcast Inductive Output Tube (IOT) capable of 30 kW. The new RF system uses one IOT amplifier on multiple cavities as opposed to one amplifier per cavity as was originally used. In addition, the new RF system supports a proposed 12 GeV energy upgrade to CEBAF. We are currently halfway through the upgrade with three IOTs in operation and the remaining one nearly installed. This paper reports on the new RF system and the IOT performance.

  4. RF System High Power Amplifier Software Conversion at Jefferson Lab

    SciTech Connect

    G. Lahti; H. Dong; T. Seegerger

    2006-10-31

    Jefferson Lab is in the process of converting the RF system from analog RF modules and non-smart high power amplifiers (HPAs) to digital RF modules and smart HPAs. The present analog RF module controls both the RF signal and the non-smart HPA hardware. The new digital RF module will only control the RF signal, so the new HPA must include embedded software. This paper will describe the conversion from a software perspective, including the initial testing, the intermediate mixed system of old and new units, and finally the totally new RF system.

  5. Airborne RF Measurement System and Analysis of Representative Flight RF Environment

    NASA Technical Reports Server (NTRS)

    Koppen, Sandra V.; Ely, Jay J.; Smith, Laura J.; Jones, Richard A.; Fleck, Vincent J.; Salud, Maria Theresa; Mielnik, John

    2007-01-01

    Environmental radio frequency (RF) data over a broad band of frequencies were needed to evaluate the airspace around several airports. An RF signal measurement system was designed using a spectrum analyzer connected to an aircraft VHF/UHF navigation antenna installed on a small aircraft. This paper presents an overview of the RF measurement system and provides analysis of a sample of RF signal measurement data over a frequency range of 30 MHz to 1000 MHz.

  6. Laser/rf personnel identification system

    NASA Astrophysics Data System (ADS)

    Zari, Michael C.; Ward, Reeder N.; Hess, David A.; Anderson, Christopher S.

    1995-05-01

    This paper documents the design of a Laser/RF Personnel Identification System developed for the US Army Communications and Electronics Command (CECOM) for soldier identification. The system has dual use applications, including law enforcement officer protection, and includes a laser interrogation unit with a programmable activation code. The interrogation unit is very directive for low probability of intercept (LPI), which is of interest during covert operations. A responder unit, worn by the law enforcement personnel or soldier, transmits an LPI radio frequency (RF) response only after receiving the proper interrogation code. The basic subsystems for the identification system are a laser interrogation unit, an RF responder unit, and a programming/synchronization unit. In this paper, the operating principles for the subsystems are reviewed and design issues are discussed. In addition to the design performed for CECOM, a breadboard system was developed to validate the concept. Hardware implementation is reviewed and field testing of the breadboard is presented.

  7. Airborne RF Measurement System (ARMS) and Analysis of Representative Flight RF Environment

    NASA Technical Reports Server (NTRS)

    Koppen, Sandra V.; Ely, Jay J.; Smith, Laura J.; Jones, Richard A.; Fleck, Vincent J.; Salud, Maria Theresa; Mielnik, John J.

    2007-01-01

    Environmental radio frequency (RF) data over a broad band of frequencies (30 MHz to 1000 MHz) were obtained to evaluate the electromagnetic environment in airspace around several airports. An RF signal measurement system was designed utilizing a spectrum analyzer connected to the NASA Lancair Columbia 300 aircraft's VHF/UHF navigation antenna. This paper presents an overview of the RF measurement system and provides analysis of sample RF signal measurement data. This aircraft installation package and measurement system can be quickly returned to service if needed by future projects requiring measurement of an RF signal environment or exploration of suspected interference situations.

  8. Modular open RF architecture: extending VICTORY to RF systems

    NASA Astrophysics Data System (ADS)

    Melber, Adam; Dirner, Jason; Johnson, Michael

    2015-05-01

    Radio frequency products spanning multiple functions have become increasingly critical to the warfighter. Military use of the electromagnetic spectrum now includes communications, electronic warfare (EW), intelligence, and mission command systems. Due to the urgent needs of counterinsurgency operations, various quick reaction capabilities (QRCs) have been fielded to enhance warfighter capability. Although these QRCs were highly successfully in their respective missions, they were designed independently resulting in significant challenges when integrated on a common platform. This paper discusses how the Modular Open RF Architecture (MORA) addresses these challenges by defining an open architecture for multifunction missions that decomposes monolithic radio systems into high-level components with welldefined functions and interfaces. The functional decomposition maximizes hardware sharing while minimizing added complexity and cost due to modularization. MORA achieves significant size, weight and power (SWaP) savings by allowing hardware such as power amplifiers and antennas to be shared across systems. By separating signal conditioning from the processing that implements the actual radio application, MORA exposes previously inaccessible architecture points, providing system integrators with the flexibility to insert third-party capabilities to address technical challenges and emerging requirements. MORA leverages the Vehicular Integration for Command, Control, Communication, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR)/EW Interoperability (VICTORY) framework. This paper concludes by discussing how MORA, VICTORY and other standards such as OpenVPX are being leveraged by the U.S. Army Research, Development, and Engineering Command (RDECOM) Communications Electronics Research, Development, and Engineering Center (CERDEC) to define a converged architecture enabling rapid technology insertion, interoperability and reduced SWaP.

  9. Iodization of rf sputter induced disordered Ag thin films reveals volume plasmon-exciton 'transition'

    SciTech Connect

    Bharathi Mohan, D.; Sunandana, C. S.

    2006-09-15

    Quasiamorphous Ag films of thicknesses ranging from 5 to 30 nm were prepared using rf magnetron sputtering technique and their controlled iodization was carried out for selected durations in the range of 15 min-60 h at room temperature. As deposited Ag and iodized films were characterized using x-ray diffraction (XRD), atomic force microscope (AFM), and optical absorption techniques. From XRD, {gamma} and {beta}+{gamma} (mixed) phases of AgI nanoparticles have been observed for 5-10 and 20-30 nm thick films, respectively. Lattice parameters (a and c) and average strain ({epsilon}) were calculated versus iodization time for {gamma} and {beta}-AgI nanoparticles. Uniform and nonuniform spherically shaped AgI nanoparticles ({approx}20-130 nm) are realized through AFM for 5-10 and 20-30 nm thick films. Optical absorption shows volume plasmons (classified as PR1) for short duration iodization, which ''decay'' upon further iodization to convert to Z{sub 1,2} and Z{sub 3} excitons at 420 and 330 nm, respectively, in the manner of a metal-semiconductor/dielectric phase transition. Ag 'colloidal' particles (classified as PR2) are formed for 5-10 nm thick films and thereby control the {gamma} phase--a significant and applicable effect attributed to critical film thickness. With increasing thickness, a surface strain field lifting the degeneracy of the valence band results in Z{sub 1,2} and Z{sub 3} exciton formation at room temperature. Blueshift in the exciton absorption with decreasing film thickness implies the progressive quantum confinement due to decrease in the particle size. A thickness induced phase transition from {gamma}-AgI to {beta}-AgI is discussed by means of x-ray diffraction and optical absorption studies.

  10. Simulations of percutaneous RF ablation systems

    NASA Astrophysics Data System (ADS)

    Ryan, Thomas P.; Kwok, Jonathan; Beetel, Robert J.

    2003-06-01

    Breast and liver cancers provide an ongoing challenge in regard to treatment efficacy and successful clinical outcomes. A variety of percutaneous technology has been applied for thermal treatment of the liver and breast, including laser, microwave, cryogenic and radiofrequency (RF) devices. When simplicity and cost are factored in, RF hardware and applicators offer the most cost-effective treatment pathway by interventional radiologists and surgeons. To model percutaneous RF treatments in liver and breast, simulations were done in 3D with a finite element model. Three RF systems were modeled, including 1) single needle; 2) clustered needle, cooled and uncooled; and 3) deployable, hook electrodes. The results show the limitations of the systems in percutaneous procedures, depending on temperature limits, duration of treatment, and whether the devices are cooled or uncooled. For thermal treatment, the isotherm of 55°C was considered the margin of coagulation necrosis. The 3-D volumes of 55°C and 65°C isotherm shells aid in the selection of the best method to improve clinical outcomes, while paying attention to the size and shape of the applicator and duration of treatment.

  11. ILC RF System R and D

    SciTech Connect

    Adolphsen, Chris; /SLAC

    2012-07-03

    The Linac Group at SLAC is actively pursuing a broad range of R&D to improve the reliability and reduce the cost of the L-band (1.3 GHz) rf system proposed for the ILC linacs. Current activities include the long-term evaluation of a 120 kV Marx Modulator driving a 10 MW Multi-Beam Klystron, design of a second-generation Marx Modulator, testing of a sheet-beam gun and beam transport system for a klystron, construction of an rf distribution system with remotely-adjustable power tapoffs, and development of a system to combine the power from many klystrons in low-loss circular waveguide where it would be tapped-off periodically to power groups of cavities. This paper surveys progress during the past few years.

  12. NSLS-II RF Cryogenic System

    SciTech Connect

    Rose, J.; Dilgen, T.; Gash, B.; Gosman, J.; Mortazavi, P.; Papu, J.; Ravindranath, V.; Sikora, R.; Sitnikov, A.; Wilhelm, H.; Jia, Y.; Monroe, C.

    2015-05-03

    The National Synchrotron Light Source II is a 3 GeV X-ray user facility commissioned in 2014. A new helium refrigerator system has been installed and commissioned to support the superconducting RF cavities in the storage ring. Special care was taken to provide very stable helium and LN2 pressures and flow rates to minimize microphonics and thermal effects at the cavities. Details of the system design along with commissioning and early operations data will be presented.

  13. Modulator considerations for the SNS RF system

    SciTech Connect

    Tallerico, P.J.; Reass, W.A.

    1998-12-31

    The Spallation Neutron Source (SNS) is an intense neutron source for neutron scattering experiments. The project is in the research stage, with construction funding beginning next year. The SNS is comprised of an ion source, a 1,000 MeV, H{sup {minus}} linear accelerator, an accumulator ring, a neutron producing target, and experimental area to utilize the scattering of the neutrons. The linear accelerator is RF driven, and the peak beam current is 27 mA and the beam duty factor is 5.84%. The peak RF power required is 104 MW, and the H{sup {minus}} beam pulse length is 0.97 ms at a 60 Hz repetition rate. The RF pulses must be about 0.1 ms longer than the beam pulses, due to the Q of the accelerating cavities, and the time required to establish control of the cavity fields. The modulators for the klystrons in this accelerator are discussed in this paper. The SNS is designed to be expandable, so the beam power can be doubled or even quadrupled in the future. One of the double-power options is to double the beam pulse length and duty factor. The authors are specifying the klystrons to operate in this twice-duty-factor mode, and the modulator also should be expandable to 2 ms pulses at 60 Hz. Due to the long pulse length and low RF frequency of 805 MHz, the klystron power is specified at 2.5 MW peak, and the RF system will have 56 klystrons at 805 MHz, and three 1.25 MW peak power klystrons at 402.5 MHz for the low energy portion of the accelerator. The low frequency modulators are conventional floating-deck modulation anode control systems.

  14. Spallation neutron source/proposed rf system

    SciTech Connect

    Meth, M.; Brennan, J.M.

    1993-09-30

    The rf system for the synchrotrons of the spallation neutron source is designed to accelerate 1.4 {times} 10{sup 14} protons/pulse to an energy of 3.6 GeV. Injection energy is 600 MeV. The synchrotron repetition frequency is 30 Hz, with a 50% duty factor. The choice of operating frequency is somewhat arbitrary. The authors propose a low frequency of 1.3 to 1.6 MHz, which is the second harmonic of the revolution frequency. The advantages of such a low frequency system are: (1) There will be two bunches in the machines and the time between bunches will be sufficiently long to allow for the rise time of the extraction kicker. No missing bunches will be necessary, which simplifies injection, and transient beam loading problems are avoided. (2) With only two bunches there are no unstable coupled-bunch modes of longitudinal instability. (3) In multi-gap low frequency cavities the transient time factor is essentially unity because the rf wavelength is much longer than the cavity dimensions. (4) Cavities in this low frequency range are basically lumped-element type structures, where the sources of the inductance and capacitance are clearly identified. This allows effective control of higher order mode impedances in such cavities. (5) Ferrite-loaded low-frequency cavities are necessarily low impedance structures; ferrites are lossy. This low impedance makes it possible to achieve system stability without large amounts of feedback in a heavily beam loaded system. (6) BNL has a good deal of experience in building rf systems in this range of frequency, voltage, and power level. This report outlines the essential parameters of a practical rf system for the synchrotrons of the Spallation Neutron Source. The design uses materials, ferrites and vacuum tubes, that are commercially available and with which the laboratory has recent experience.

  15. Superconducting RF systems for eRHIC

    SciTech Connect

    Belomestnykh S.; Ben-Zvi, I.; Brutus, J.C.; Hahn, H. et al

    2012-05-20

    The proposed electron-hadron collider eRHIC will consist of a six-pass 30-GeV electron Energy Recovery Linac (ERL) and one of RHIC storage rings operating with energy up to 250 GeV. The collider design extensively utilizes superconducting RF (SRF) technology in both electron and hadron parts. This paper describes various SRF systems, their requirements and parameters.

  16. UNCERTAIN SYSTEM MODELING OF SNS RF CONTROL SYSTEM

    SciTech Connect

    S. KWON; A. REGAN; ET AL

    2001-06-01

    This paper addresses the modeling problem of the linear accelerator RF system for SNS. The cascade of the klystron and the cavity is modeled as a nominal system. In the real world, high voltage power supply ripple, Lorentz Force Detuning, microphonics, cavity RF parameter perturbations, distortions in RF components, and loop time delay imperfection exist inevitably, which must be analyzed. The analysis is based on the accurate modeling of the disturbances and uncertainties. In this paper, a modern control theory is applied for modeling the disturbances, uncertainties, and for analyzing the closed loop system robust performance.

  17. The AGS Booster control system

    SciTech Connect

    Frankel, R.; Auerbach, E.; Culwick, B.; Clifford, T.; Mandell, S.; Mariotti, R.; Salwen, C.; Schumburg, N.

    1988-01-01

    Although moderate in size, the Booster construction project requires a comprehensive control system. There are three operational modes: as a high intensity proton injector for the AGS, as a heavy ion accelerator and injector supporting a wide range of ions and as a polarized proton storage injector. These requirements are met using a workstation based extension of the existing AGS control system. Since the Booster is joining a complex of existing accelerators, the new system will be capable of supporting multiuser operational scenarios. A short discussion of this system is discussed in this paper.

  18. Fermilab Tevatron high level rf accelerating systems

    SciTech Connect

    Kerns, Q.; Kerns, C.; Miller, H.; Tawser, S.; Reid, J.; Webber, R.; Wildman, D.

    1985-06-01

    Eight tuned rf cavities have been installed and operated in the F0 straight section of the Tevatron. Their mechanical placement along the beam line enables them to be operated for colliding beams as two independent groups of four cavities, group 1-4 accelerating antiprotons and group 5-8 accelerating protons. The only difference is that the spacing between cavities 4 and 5 was increased to stay clear of the F0 colliding point. The cavities can easily be rephased by switching cables in a low-level distribution system (fan-out) so that the full accelerating capability of all eight cavities can be used during fixed target operations. Likewise, the cables from capacitive probes on each cavity gap can be switched to proper lengths and summed in a fan-back system to give an rf signal representing the amplitude and phase as ''seen by the beam,'' separately for protons and antiprotons. Such signals have been used to phase lock the Tevatron to the Main Ring for synchronous transfer.

  19. Whip antenna design for portable rf systems

    NASA Astrophysics Data System (ADS)

    Ponnapalli, Saila; Canora, Frank J.

    1995-12-01

    Whip type antennas are probably the most commonly used antennas in portable rf systems, such as cordless and cellular phones, rf enabled laptop computers, personal digital assistants (PDAs), and handheld computers. Whip antennas are almost always mounted on the chassis which contains the radio and other electronics. The chassis is usually a molded plastic which is coated with a conducting paint for EMI purposes. The chassis which appears as a lossy conductor to the antenna, has several effects -- detuning, altering the gain of the antenna, and shadowing its radiation pattern. Extensive modeling and measurements must be performed in order to fully characterize the affects of the chassis on the whip antenna, and to optimize antenna type, orientation and position. In many instances, modeling plays a more important role in prediction of the performance of whip antennas, since measurements become difficult due to the presence of common mode current on feed cables. In this paper models and measurements are used to discuss the optimum choice of whip antennas and the impact of the chassis on radiation characteristics. A modeling tool which has been previously described and has been successfully used to predict radiated field patterns is used for simulations, and measured and modeled results are shown.

  20. LHC RF System Time-Domain Simulation

    SciTech Connect

    Mastorides, T.; Rivetta, C.; /SLAC

    2010-09-14

    Non-linear time-domain simulations have been developed for the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC). These simulations capture the dynamic behavior of the RF station-beam interaction and are structured to reproduce the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They are also a valuable tool for the study of diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Results from these studies and related measurements from PEP-II and LHC have been presented in multiple places. This report presents an example of the time-domain simulation implementation for the LHC.

  1. The system of RF beam control for electron gun

    NASA Astrophysics Data System (ADS)

    Barnyakov, A. M.; Chernousov, Yu. D.; Ivannikov, V. I.; Levichev, A. E.; Shebolaev, I. V.

    2015-06-01

    The system of RF control of three-electrode electron gun current is described. It consists of a source of microwave signal, coaxial line, coaxial RF switch and RF antenna lead. The system allows one to get the electron beam in the form of bunches with the frequency of the accelerating section to achieve the capture of particles in the acceleration mode close to 100%. The results of calculation and analysis of the elements of the system are presented. Characteristics of the devices are obtained experimentally. The results of using RF control in three-electrode electron gun at electron linear accelerator are described.

  2. Fermilab tevatron high level RF accelerating systems

    SciTech Connect

    Kerns, Q.; Kerns, C.; Miller, H.; Reid, J.; Tawzer, S.; Webber, R.; Wildman, D.

    1985-10-01

    Eight tuned rf cavities have been installed and operated in the F0 straight section of the Tevatron. Their mechanical placement along the beam line enables them to be operated for colliding beams as two independent groups of four cavities, group 1-4 accelerating antiprotons and group 5-8 accelerating protons. The only difference is that the spacing between cavities 4 and 5 was increased to stay clear of the F0 colliding point. The cavities can easily be rephased by switching cables in a low-level distribution system (fan-out) so that the full accelerating capability of all eight cavities can be used during fixed target operations. Likewise, the cables from capacitive probes on each cavity gap can be switched to proper lengths and summed in a fan-back system to give an rf signal representing the amplitude and phase as ''seen by the beam,'' separately for protons and antiprotons. Such signals have been used to phase lock the Tevatron to the Main Ring for synchronous transfer. A cavity consists of two quarter-wave resonators placed back to back with a coaxial drift tube separating the two accelerating gaps by ..pi.. radians. The cavities are very similar to the prototype which has been previously described/sup 3/ and is operating as Station 8 in the Tevatron. Only additional water cooling around the high current region of the drift tube supports and a double loop used to monitor the unbalance current through the Hipernom mode damping resistor have been added. Each cavity has a Q of about7100, a shunt impedance of 1.2 M..cap omega.., and is capable of running cw with a peak accelerating voltage of 360

  3. Rf system considerations for a large hadron collider

    SciTech Connect

    Raka, E.

    1988-01-01

    In this paper, we shall discuss how we arrive at a particular choice of voltage and frequency; the type of acceleration structure that would be suitable for obtaining the required voltage and resonant impedance; static beam loading including a simplified beam stability criterion involving the beam current and total rf system shunt impedance; the basic principle of rf phase and frequency control loops; and the effect of rf noise and its interaction with these loops. Finally, we shall consider the need for and design of rf systems to damp independently coherent oscillations of individual bunches or groups of bunches. 30 refs., 17 figs., 2 tabs.

  4. Conceptual design of the 26. 7 MHz RF system for RHIC

    SciTech Connect

    Rose, J.; Deng, D.P.; McKenzie-Wilson, R.; Pirkl, W.; Ratti, A.

    1993-01-01

    The 26.7 MHz (harmonic No. h=342) RF system will be used to capture the injected bunched beam from the AGS and accelerate it to a kinetic energy of up to 250 GeV for protons; 100 GeV/u for gold ions. All ions except protons cross transition, and are finally transferred to a storage RF system working at 196 MHz. Each RHIC ring will be provided with two single-ended capacitively loaded quarter-wave cavities; each of these can be dynamically tuned by 100 kHz to compensate for the change in speed of the beam, and can deliver at least 200 kV voltage. A 100 kW tetrode amplifier with local RF feedback is directly coupled to the cavity to minimize phase delay. Prototypes of cavity and amplifier have been built and first test results are presented.

  5. Conceptual design of the 26.7 MHz RF system for RHIC

    SciTech Connect

    Rose, J.; Deng, D.P.; McKenzie-Wilson, R.; Pirkl, W.; Ratti, A.

    1993-06-01

    The 26.7 MHz (harmonic No. h=342) RF system will be used to capture the injected bunched beam from the AGS and accelerate it to a kinetic energy of up to 250 GeV for protons; 100 GeV/u for gold ions. All ions except protons cross transition, and are finally transferred to a storage RF system working at 196 MHz. Each RHIC ring will be provided with two single-ended capacitively loaded quarter-wave cavities; each of these can be dynamically tuned by 100 kHz to compensate for the change in speed of the beam, and can deliver at least 200 kV voltage. A 100 kW tetrode amplifier with local RF feedback is directly coupled to the cavity to minimize phase delay. Prototypes of cavity and amplifier have been built and first test results are presented.

  6. Active high-power RF switch and pulse compression system

    DOEpatents

    Tantawi, Sami G.; Ruth, Ronald D.; Zolotorev, Max

    1998-01-01

    A high-power RF switching device employs a semiconductor wafer positioned in the third port of a three-port RF device. A controllable source of directed energy, such as a suitable laser or electron beam, is aimed at the semiconductor material. When the source is turned on, the energy incident on the wafer induces an electron-hole plasma layer on the wafer, changing the wafer's dielectric constant, turning the third port into a termination for incident RF signals, and. causing all incident RF signals to be reflected from the surface of the wafer. The propagation constant of RF signals through port 3, therefore, can be changed by controlling the beam. By making the RF coupling to the third port as small as necessary, one can reduce the peak electric field on the unexcited silicon surface for any level of input power from port 1, thereby reducing risk of damaging the wafer by RF with high peak power. The switch is useful to the construction of an improved pulse compression system to boost the peak power of microwave tubes driving linear accelerators. In this application, the high-power RF switch is placed at the coupling iris between the charging waveguide and the resonant storage line of a pulse compression system. This optically controlled high power RF pulse compression system can handle hundreds of Megawatts of power at X-band.

  7. Booster Synchrotron RF System Upgrade for SPEAR3

    SciTech Connect

    Park, Sanghyun; Corbett, Jeff; /SLAC

    2012-07-06

    Recent progress at the SPEAR3 includes the increase in stored current from 100 mA to 200 mA and top-off injection to allow beamlines to stay open during injection. Presently the booster injects 3.0 GeV beam to SPEAR3 three times a day. The stored beam decays to about 150 mA between the injections. The growing user demands are to increase the stored current to the design value of 500 mA, and to maintain it at a constant value within a percent or so. To achieve this goal the booster must inject once every few minutes. For improved injection efficiency, all RF systems at the linac, booster and SPEAR3 need to be phase-locked. The present booster RF system is basically a copy of the SPEAR2 RF system with 358.5 MHz and 40 kW peak RF power driving a 5-cell RF cavity for 1.0 MV gap voltage. These requirements entail a booster RF system upgrade to a scaled down version of the SPEAR3 RF system of 476.3 MHz with 1.2 MW cw klystron output power capabilities. We will analyze each subsystem option for their merits within budgetary and geometric space constraints. A substantial portion of the system will come from the decommissioned PEP-II RF stations.

  8. Versatile Low Level RF System For Linear Accelerators

    SciTech Connect

    Potter, James M.

    2011-06-01

    The Low Level RF (LLRF) system is the source of all of the rf signals required for an rf linear accelerator. These signals are amplified to drive accelerator and buncher cavities. It can even provide the synchronizing signal for the rf power for a synchrotron. The use of Direct Digital Synthesis (DDS) techniques results in a versatile system that can provide multiple coherent signals at the same or different frequencies with adjustable amplitudes and phase relations. Pulsing the DDS allows rf switching with an essentially infinite on/off ratio. The LLRF system includes a versatile phase detector that allows phase-locking the rf frequency to a cavity at any phase angle over the full 360 deg. range. With the use of stepper motor driven slug tuners multiple cavity resonant frequencies can be phase locked to the rf source frequency. No external phase shifters are required and there is no feedback loop phase setup required. All that is needed is to turn the frequency feedback on. The use of Digital Signal Processing (DSP) allows amplitude and phase control over the entire rf pulse. This paper describes the basic principles of a LLRF system that has been used for both proton accelerators and electron accelerators, including multiple tank accelerators, sub-harmonic and fundamental bunchers, and synchrotrons.

  9. Versatile Low Level RF System For Linear Accelerators

    NASA Astrophysics Data System (ADS)

    Potter, James M.

    2011-06-01

    The Low Level RF (LLRF) system is the source of all of the rf signals required for an rf linear accelerator. These signals are amplified to drive accelerator and buncher cavities. It can even provide the synchronizing signal for the rf power for a synchrotron. The use of Direct Digital Synthesis (DDS) techniques results in a versatile system that can provide multiple coherent signals at the same or different frequencies with adjustable amplitudes and phase relations. Pulsing the DDS allows rf switching with an essentially infinite on/off ratio. The LLRF system includes a versatile phase detector that allows phase-locking the rf frequency to a cavity at any phase angle over the full 360° range. With the use of stepper motor driven slug tuners multiple cavity resonant frequencies can be phase locked to the rf source frequency. No external phase shifters are required and there is no feedback loop phase setup required. All that is needed is to turn the frequency feedback on. The use of Digital Signal Processing (DSP) allows amplitude and phase control over the entire rf pulse. This paper describes the basic principles of a LLRF system that has been used for both proton accelerators and electron accelerators, including multiple tank accelerators, sub-harmonic and fundamental bunchers, and synchrotrons.

  10. RF modulated fiber optic sensing systems and their applications

    NASA Technical Reports Server (NTRS)

    Adamovsky, Grigory; Eustace, John G.

    1992-01-01

    A fiber optic sensing system with an intensity sensor and a Radio Frequency (RF) modulated source was shown to have sensitivity and resolution much higher than a comparable system employing low modulating frequencies or DC mode of operation. Also the RF modulation with an appropriate configuration of the sensing system provides compensation for the unwanted intensity losses. The basic principles and applications of a fiber optic sensing system employing an RF modulated source are described. In addition the paper discusses various configurations of the system itself, its components, and modulation and detection schemes. Experimental data are also presented.

  11. Traveling Wave RF Systems for Helical Cooling Channels

    SciTech Connect

    Yonehara, K.; Lunin, A.; Moretti, A.; Popovic, M.; Romanov, G.; Neubauer, M.; Johnson, R.P.; Thorndahl, L.; /CERN

    2009-05-01

    The great advantage of the helical ionization cooling channel (HCC) is its compact structure that enables the fast cooling of muon beam 6-dimensional phase space. This compact aspect requires a high average RF gradient, with few places that do not have cavities. Also, the muon beam is diffuse and requires an RF system with large transverse and longitudinal acceptance. A traveling wave system can address these requirements. First, the number of RF power coupling ports can be significantly reduced compared with our previous pillbox concept. Secondly, by adding a nose on the cell iris, the presence of thin metal foils traversed by the muons can possibly be avoided. We show simulations of the cooling performance of a traveling wave RF system in a HCC, including cavity geometries with inter-cell RF power couplers needed for power propagation.

  12. RF system considerations for large high-duty-factor linacs

    SciTech Connect

    Lynch, M.T.; Ziomek, C.D.; Tallerico, P.J.; Regan, A.H.; Eaton, L.; Lawrence, G.

    1994-09-01

    RF systems are often a major cost item for linacs, but this is especially true for large high-duty-factor linacs (up to and including CW) such as the Accelerator for Production of Tritium (APT) or the Accelerator for Transmutation of nuclear Waste (ATW). In addition, the high energy and high average beam current of these machines (approximately 1 GeV, 100--200 mA) leads to a need for excellent control of the accelerating fields in order to minimize the possibility of beam loss in the accelerator and the resulting activation. This paper will address the key considerations and limitations in the design of the RF system. These considerations impact the design of both the high power RF components and the RF controls. As might be expected, the two concerns sometimes lead to conflicting design requirements. For example minimum RF operating costs lead to a desire for operation near saturation of the high power RF generators in order to maximize the operating efficiency. Optimal control of the RF fields leads to a desire for maximum overdrive capability in those same generators in order to respond quickly to disturbances of the accelerator fields.

  13. High power RF systems for the BNL ERL project

    SciTech Connect

    Zaltsman, A.; Lambiase, R.

    2011-03-28

    The Energy Recovery Linac (ERL) project, now under construction at Brookhaven National Laboratory, requires two high power RF systems. The first RF system is for the 703.75 MHz superconducting electron gun. The RF power from this system is used to drive nearly half an Ampere of beam current to 2 MeV. There is no provision to recover any of this energy so the minimum amplifier power is 1 MW. It consists of 1 MW CW klystron, transmitter and power supplies, 1 MW circulator, 1 MW dummy load and a two-way power splitter. The second RF system is for the 703.75 MHz superconducting cavity. The system accelerates the beam to 54.7 MeV and recovers this energy. It will provide up to 50 kW of CW RF power to the cavity. It consists of 50 kW transmitter, circulator, and dummy load. This paper describes the two high power RF systems and presents the test data for both.

  14. R&D ERL: High power RF systems

    SciTech Connect

    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.

  15. Connect Global Positioning System RF Module

    NASA Technical Reports Server (NTRS)

    Franklin, Garth W.; Young, Lawrence E.; Ciminera, Michael A.; Tien, Jeffrey Y.; Gorelik, Jacob; Okihiro, Brian Bachman; Koelewyn, Cynthia L.

    2012-01-01

    The CoNNeCT Global Positioning System RF Module (GPSM) slice is part of the JPL CoNNeCT Software Defined Radio (SDR). CoNNeCT is the Communications, Navigation, and Net working reconfigurable Testbed project that is part of NASA's Space Communication and Nav igation (SCaN) Program. The CoNNeCT project is an experimental dem onstration that will lead to the advancement of SDRs and provide a path for new space communication and navigation systems for future NASA exploration missions. The JPL CoNNeCT SDR will be flying on the International Space Station (ISS) in 2012 in support of the SCaN CoNNeCT program. The GPSM is a radio-frequency sampler module (see Figure 1) that directly sub-harmonically samples the filtered GPS L-band signals at L1 (1575.42 MHz), L2 (1227.6 MHz), and L5 (1176.45 MHz). The JPL SDR receives GPS signals through a Dorne & Margolin antenna mounted onto a choke ring. The GPS signal is filtered against interference, amplified, split, and fed into three channels: L1, L2, and L5. In each of the L-band channels, there is a chain of bandpass filters and amplifiers, and the signal is fed through each of these channels to where the GPSM performs a one-bit analog-to-digital conversion (see Figure 2). The GPSM uses a sub-harmonic, single-bit L1, L2, and L5 sampler that samples at a clock rate of 38.656 MHz. The new capability is the down-conversion and sampling of the L5 signal when previous hardware did not provide this capability. The first GPS IIF Satellite was launched in 2010, providing the new L5 signal. With the JPL SDR flying on the ISS, it will be possible to demonstrate navigation solutions with 10-meter 3-D accuracy at 10-second intervals using a field-program mable gate array (FPGA)-based feedback loop running at 50 Hz. The GPS data bits will be decoded and used in the SDR. The GPSM will also allow other waveforms that are installed in the SDR to demonstrate various GNSS tracking techniques.

  16. RF system at HIRFL-CSR main ring

    NASA Astrophysics Data System (ADS)

    Zhang, W. Z.; Zhang, D. S.; Zhan, W. L.

    2001-12-01

    A heavy ion cooler-storage ring HIRFL-CSR[1] has been constructed at IMP. It consists of a main ring (CSRm) and an experimental ring (CSRe). Two RF cavities will be employed for CSRm. One is for beam acceleration, and another is for beam RF stacking. The accelerating cavity is designed to accelerate the beam from 10-50 MeV/u to 400-900 MeV/u with harmonic number h=1. The peak RF voltage is 8.0 kV and frequency range is from 0.25 MHz to 1.7 MHz. The RF stacking cavity with maximum voltage amplitude of 20 kV and tunable frequency range 6.0-14.0 MHz is used to capture the injected bunches from injector SSC (or SFC) and to accumulate the beam to high intensity by RF stacking method. In the present paper, the designed RF parameters and the details of hardware for the RF system are described.

  17. SIMULATION STUDY AND INITIAL TEST OF THESNS RING RF SYSTEM

    SciTech Connect

    Zhang, Yan; Ma, Hengjie; Holmes, Jeffrey A; Champion, Mark; Chu, Paul; Cousineau, Sarah M; Hardek, Thomas W; Plum, Michael A; Danilov, Viatcheslav; Piller, Chip

    2008-01-01

    The rfsimulator code was developed for the study of the Spallation Neutron Source (SNS) dual-harmonic ring RF control. It uses time-domain solvers to compute beam-cavity interactions and FFT methods to simulate the time responses of the linear RF system. The important elements of the system considered in the model include beam loading, dynamic cavity detuning, circuit bandwidth, loop delay, proportional-integral controller for feedback and adaptive feed forward, stochastic noise, width-in-turn loop parameter change, beam current fluctuation, and bunch leakage. As the beam power increases, beam loss in the ring goes up and thus precise control of the bunching RF phase and amplitude is required to limit beam loss. The code will help in the development of a functional RF control and in achieving the goal of minimizing beam loss in the accumulator ring.

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

    SciTech Connect

    Rees, D.

    1997-09-01

    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.

  19. Applications of barrier bucket RF systems at Fermilab

    SciTech Connect

    Bhat, C.M.; /Fermilab

    2006-03-01

    In recent years, the barrier rf systems have become important tools in a variety of beam manipulation applications at synchrotrons. Four out of six proton synchrotrons at Fermilab are equipped with broad-band barrier rf systems. All of the beam manipulations pertaining to the longitudinal phase space in the Fermilab Recycler (synchrotron used for antiproton storage) are carried out using a barrier system. Recently, a number of new applications of barrier rf systems have been developed- the longitudinal momentum mining, longitudinal phase-space coating, antiproton stacking, fast bunch compression and more. Some of these techniques have been critical for the recent spectacular success of the collider performance at the Fermilab Tevatron. Barrier bunch coalescing to produce bright proton bunches has a high potential to increase proton antiproton luminosity significantly. In this paper, I will describe some of these techniques in detail. Finally, I make a few general remarks on issues related to barrier systems.

  20. New rf power system for SuperHILAC

    SciTech Connect

    Fugitt, J.; Lancaster, H.; Sorensen, R.

    1985-05-01

    The upgraded rf system for the SuperHILAC is now operational using 9 new tetrode amplifiers. Each amplifier can produce in excess of 1MW of 70 Mhz pulsed rf power. Ferrite is used to decouple the screen grid circuit and to absorb parasitic oscillations. This results in a very stable amplifier with reasonable gain. This system uses a common 8 MW anode power supply and crowbar system. Overall system efficiency has been increased significantly. We project a 3 year payback on the equipment cost, realized from the power savings alone. 2 refs., 5 figs.

  1. Laser crosslink configurations for RF satellite communications systems

    NASA Astrophysics Data System (ADS)

    Sebacher, K. S.; Lambert, S. G.; Pautler, J. A.; Carter, J. P.

    Predictions of future satellite communications traffic indicate that an increased capacity for satellite communications systems is required. Crosslinks between satellites provide improvements in communications throughput for these systems. Crosslinks also increase system flexibility and remove the dependence of world-wide information flow on relay ground stations located outside the continental United States. Laser crosslinks provide the additional advantage of eliminating susceptibility to space-based or ground-based jammers. Laser terminals are also smaller and require smaller antennas than an RF terminal. This paper describes the advantages of adding laser crosslinks to RF satellite communications systems. Characteristics of the required RF/optical interfaces on-board the satellites are addessed. Terminal configurations that provide reliable, accurate laser communications at high data rates are described.

  2. A FLYING WIRE SYSTEM IN THE AGS.

    SciTech Connect

    HUANG,H.; BUXTON,W.; MAHLER,G.; MARUSIC,A.; ROSER,T.; SMITH,G.; SYPHERS,M.; WILLIAMS,N.; WITKOVER,R.

    1999-03-29

    As the AGS prepares to serve as the injector for RHIC, monitoring and control of the beam transverse emittance become a major and important topic. Before the installation of the flying wire system, the emittance was measured with ionization profile monitors in the AGS, which require correction for space charge effects. It is desirable to have a second means of measuring profile that is less depend on intensity. A flying wire system has been installed in the AGS recently to perform this task. This paper discusses the hardware and software setup and the capabilities of the system.

  3. Klystron 'efficiency loop' for the ALS storage ring RF system

    SciTech Connect

    Kwiatkowski, Slawomir; Julian, Jim; Baptiste, Kenneth

    2002-05-20

    The recent energy crisis in California has led us to investigate the high power RF systems at the Advanced Light Source (ALS) in order to decrease the energy consumption and power costs. We found the Storage Ring Klystron Power Amplifier system operating as designed but with significant power waste. A simple proportional-integrator (PI) analog loop, which controls the klystron collector beam current, as a function of the output RF power, has been designed and installed. The design considerations, besides efficiency improvement, were to interface to the existing system without major expense. They were to also avoid the klystron cathode power supply filter's resonance in the loop's dynamics, and prevent a conflict with the existing Cavity RF Amplitude Loop dynamics. This efficiency loop will allow us to save up to 700 MW-hours of electrical energy per year and increase the lifetime of the klystron.

  4. Low Level RF System for Jefferson Lab Cryomodule Test Facility

    SciTech Connect

    Tomasz Plawski; Trent Allison; Jean Delayen; J. Hovater; Thomas Powers

    2003-05-01

    The Jefferson Lab Cryomodule Test Facility (CMTF) has been upgraded to test and commission SNS and CEBAF Energy Upgrade cryomodules. Part of the upgrade was to modernize the superconducting cavity instrumentation and control. We have designed a VXI based RF control system exclusively for the production testing of superconducting cavities. The RF system can be configured to work either in Phase Locked Loop (PLL) or Self Excited Loop (SEL) mode. It can be used to drive either SNS 805 MHz or CEBAF Energy Upgrade 1497 MHz superconducting cavities and can be operated in pulsed or continuous wave (CW) mode. The base design consists of RF-analog and digital sections. The RF-analog section includes a Voltage Control Oscillator (VCO), phase detector, I&Q modulator and ''low phase shift'' limiter. The digital section controls the analog section and includes ADC, FPGA, and DAC . We will discuss the design of the RF system and how it relates to the support of cavity testing.

  5. THE RF SYSTEM DESIGN FOR THE SPALLATION NEUTRON SOURCE

    SciTech Connect

    D. REES; M. LYNCH; ET AL

    2001-06-01

    Spallation Neutron Source (SNS) accelerator includes a nominally 1000 MeV, 2 mA average current linac consisting of a radio frequency quadrapole (RFQ), drift tube linac (DTL), coupled cavity linac (CCL), a medium and high beta super conducting (SC) linac, and two buncher cavities for beam transport to the ring. Los Alamos is responsible for the RF systems for all sections of the linac. The SNS linac is a pulsed proton linac and the RF system must support a 1 msec beam pulse at up to a 60 Hz repetition rate. The RFQ and DTL utilize seven, 2.5 MW klystrons and operate at 402.5 MHz. The CCL, SC, and buncher cavities operate at 805 MHz. Six, 5 MW klystrons are utilized for the CCL and buncher cavities while eighty-one 550 kW klystrons are used for the SC cavities. All of the RF hardware for the SNS linac is currently in production. This paper will present details of the RF system-level design as well as specific details of the SNS RF equipment. The design parameters will be discussed. One of the design challenges has been achieving a reasonable cost with the very large number of high-power klystrons. The approaches we used to reduce cost and the resulting design compromises will be discussed.

  6. An Orbiting Standards Platform for communication satellite system RF measurements

    NASA Technical Reports Server (NTRS)

    Wallace, R. G.; Woodruff, J. J.

    1978-01-01

    The Orbiting Standards Platform (OSP) is a proposed satellite dedicated to performing RF measurements on space communications systems. It would consist of a quasi-geostationary spacecraft containing an ensemble of calibrated RF sources and field strength meters operating in several microwave bands, and would be capable of accurately and conveniently measuring critical earth station and satellite RF performance parameters, such as EIRP, gain, figure of merit (G/T), crosspolarization, beamwidth, and sidelobe levels. The feasibility and utility of the OSP concept has been under joint study by NASA, NBS, Comsat and NTIA. A survey of potential OSP users was conducted by NTIA as part of this effort. The response to this survey, along with certain trends in satellite communications system design, indicates a growing need for such a measurement service.

  7. Compact rf polarizer and its application to pulse compression systems

    NASA Astrophysics Data System (ADS)

    Franzi, Matthew; Wang, Juwen; Dolgashev, Valery; Tantawi, Sami

    2016-06-01

    We present a novel method of reducing the footprint and increasing the efficiency of the modern multi-MW rf pulse compressor. This system utilizes a high power rf polarizer to couple two circular waveguide modes in quadrature to a single resonant cavity in order to replicate the response of a traditional two cavity configuration using a 4-port hybrid. The 11.424 GHz, high-Q, spherical cavity has a 5.875 cm radius and is fed by the circularly polarized signal to simultaneously excite the degenerate T E114 modes. The overcoupled spherical cavity has a Q0 of 9.4 ×104 and coupling factor (β ) of 7.69 thus providing a loaded quality factor QL of 1.06 ×104 with a fill time of 150 ns. Cold tests of the polarizer demonstrated good agreement with the numerical design, showing transmission of -0.05 dB and reflection back to the input rectangular WR 90 waveguide less than -40 dB over a 100 MHz bandwidth. This novel rf pulse compressor was tested at SLAC using XL-4 Klystron that provided rf power up to 32 MW and generated peak output power of 205 MW and an average of 135 MW over the discharged signal. A general network analysis of the polarizer is discussed as well as the design and high power test of the rf pulse compressor.

  8. The RF power system for the SNS linac

    SciTech Connect

    Tallerico, P.J.; Reass, W.A.

    1998-12-31

    The initial goal of the SNS project is to produce a 1 MW average beam of protons with short pulse lengths onto a neutron-producing target. The objective of the SNS RF system is to generate 117 MW peak of pulsed 805 MHz microwave power with an accelerated beam pulse length of 1.04 ms at a 60 Hz repetition rate. The power system must be upgradeable in peak power to deliver 2 MW average power to the neutron target. The RF system also requires about 3 MW peak of RF power at 402.5 MHz, but that system is not discussed here. The design challenge is to produce an RF system at minimum cost, that is very reliable and economical to operate. The combination of long pulses and high repetition rates make conventional solutions, such as the pulse transformer and transmission line method, very expensive. The klystron, with a modulating anode, and 1.5 MW of peak output power is the baseline RF amplifier, an 56 are required in the baseline design. The authors discuss four power system configurations that are the candidates for the design. The baseline design is a floating-deck modulating anode system. A second power system being investigated is the fast-pulsed power supply, that can be turned on and off with a rise time of under 0.1 ms. This could eliminate the need for a modulator, and drastically reduce the energy storage requirements. A third idea is to use a pulse transformer with a series IGBT switch and a bouncer circuit on the primary side, as was done for the TESLA modulator. A fourth method is to use a series IGBT switch at high voltage, and not use a pulse transformer. The authors discuss the advantages and problems of these four types of power systems, but they emphasize the first two.

  9. Superfluid helium cryogenic systems for superconducting RF cavities at KEK

    SciTech Connect

    Nakai, H.; Hara, K.; Honma, T.; Hosoyama, K.; Kojima, Y.; Nakanishi, K.; Kanekiyo, T.; Morita, S.

    2014-01-29

    Recent accelerator projects at KEK, such as the Superconducting RF Test Facility (STF) for R and D of the International Linear Collider (ILC) project and the compact Energy Recovery Linac (cERL), employ superconducting RF cavities made of pure niobium, which can generate high gradient acceleration field. Since the operation temperature of these cavities is selected to be 2 K, we have developed two 2 K superfluid helium cryogenic systems for stable operation of superconducting RF cavities for each of STF and cERL. These two 2 K superfluid helium cryogenic systems are identical in principle. Since the operation mode of the cavities is different for STF and cERL, i.e. the pulse mode for STF and the continuous wave mode for cERL, the heat loads from the cavities are quite different. The 2 K superfluid helium cryogenic systems mainly consists of ordinary helium liquefiers/refrigerators, 2 K refrigerator cold boxes, helium gas pumping systems and high-performance transfer lines. The 2 K refrigerators and the high-performance transfer lines are designed by KEK. Some superconducting RF cavity cryomodules have been already connected to the 2 K superfluid helium cryogenic systems for STF and cERL respectively, and cooled down to 2 K successfully.

  10. Theory and Practice of Cavity RF Test Systems

    SciTech Connect

    Tom Powers

    2006-08-28

    Over the years Jefferson Lab staff members have performed about 2500 cold cavity tests on about 500 different superconducting cavities. Most of these cavities were later installed in 73 different cryomodules, which were used in three different accelerators. All of the cavities were tested in our vertical test area. About 25% of the cryomodules were tested in our cryomodule test facility and later commissioned in an accelerator. The remainder of the cryomodules were tested and commissioned after they were installed in their respective accelerator. This paper is an overview which should provide a practical background in the RF systems used to test the cavities as well as provide the mathematics necessary to convert the raw pulsed or continuous wave RF signals into useful information such as gradient, quality factor, RF-heat loads and loaded Q?s. Additionally, I will provide the equations necessary for determining the measurement error associated with these values.

  11. The development of the electrically controlled high power RF switch and its application to active RF pulse compression systems

    NASA Astrophysics Data System (ADS)

    Guo, Jiquan

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

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

    SciTech Connect

    Guo, Jiquan

    2008-12-01

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

  13. Realization of an X-Band RF System for LCLS

    SciTech Connect

    McIntosh, P.; Akre, R.; Brooks, W.; Emma, P.; Rago, C.; /SLAC

    2005-06-15

    A single X-band (11.424 GHz) accelerating structure is to be incorporated in the LINAC Coherent Light Source (LCLS) design to linearize the energy-time correlation (or gradient) across each bunch; features which originate in the preceding accelerating structures (L0 and L1) [1]. This harmonic RF system will operate near the negative RF crest to decelerate the beam, reducing these non-linear components of the correlation, providing a more efficient compression in the downstream bunch compressor chicanes (BC1 and BC2). These non-linear correlation components, if allowed to grow, would lead to Coherent Synchrotron Radiation (CSR) instabilities in the chicanes, effectively destroying the coherence of the photon radiation in the main LCLS undulator. The many years devoted at SLAC in the development of X-band RF components for the NLC/JLC linear collider project [2], has enabled the technical and financial realization of such an RF system for LCLS. This paper details the requirements for the X-band system and the proposed scheme planned for achieving those requirements.

  14. THE SPALLATION NEUTRON SOURCE CRYOMODULE TEST STAND RF SYSTEM

    SciTech Connect

    Crofford, Mark T; Ball, Jeffrey Allen; Davidson Jr, Taylor L; Hardek, Thomas W; Heidenreich, Dale A; Kasemir, Kay; Kim, Sang-Ho; Kang, Yoon

    2008-01-01

    The Spallation Neutron Source (SNS) has recently commissioned a cryomodule test facility for the repair and testing of the super-conducting radio-frequency (SRF) cavities. This facility utilizes the original 402.5/805 MHz Radio Frequency (RF) Klystron Test Stand as its power source along with dual Low Level RF (LLRF) control systems. One control system is based on the standard SNS Linac LLRF controls with a second system for open-loop only control. The system is designed to allow simultaneous testing of devices in the test cave and other devices which can be tested outside of the enclosure. Initial tests have shown good results; some improvements are yet to be implemented.

  15. The Lunar Reconnaissance Orbiter Mini RF System (Invited)

    NASA Astrophysics Data System (ADS)

    Nozette, S.

    2009-12-01

    The Miniature Radio Frequency (Mini-RF) system is manifested on the Lunar Reconnaissance Orbiter (LRO) as a technology demonstration and an extended mission science instrument. Mini-RF represents a significant step forward in space-borne RF technology and architecture. It combines synthetic aperture radar (SAR) at two wavelengths (S and X band) and two resolutions (150 m and 30 m) with interferometric and communications functionality in one lightweight (16kg) package. Previous radar observations (Earth-based, and one bistatic data set from Clementine) of the permanently shadowed regions of the lunar poles seem to indicate areas of high circular polarization ratio (CPR) consistent with volume scattering from volatile deposits (e.g. water ice) buried at shallow (0.1-1 m) depth, but only at unfavorable viewing geometries, and with inconclusive results (ref. 1-5). The LRO Mini-RF utilizes new wide band hybrid polarization architecture to measure the Stokes parameters of the reflected signal. These data will help to differentiate “true” volumetric ice reflections from ”false” returns due to angular surface regolith (ref. 6) . Additional lunar science investigations (e.g. pyroclastic deposit characterization) will also be attempted during the LRO extended mission. LRO’s lunar operations will be contemporaneous with India’s Chandrayaan-1, which carries the Forerunner Mini-SAR (S band wavelength and 150-m resolution). On orbit calibration procedures for LRO Mini RF have been validated using Chandrayaan 1 and ground based facilities (Arecibo and Greenbank Radio Observatories). References: 1) Nozette S. et al. (1996) Science 274, 1495. 2) Simpson R. and Tyler L. (1999) JGR 104, 3845. 3) Nozette S. et al. (2001) JGR 106, 23253. 4) Campbell D. et al., (2006) Nature 443, 835. 5) Feldman W. et al., (2001) JGR 106, 23231. 6) Raney R.K. (2007) IEEE Trans Geosci. Remote Sens. 45, 3397

  16. Controlling satellite communication system unwanted emissions in congested RF spectrum

    NASA Astrophysics Data System (ADS)

    Olsen, Donald; Heymann, Roger

    2007-09-01

    The International Telecommunication Union (ITU), a United Nations (UN) agency, is the agency that, under an international treaty, sets radio spectrum usage regulations among member nations. Within the United States of America (USA), the organization that sets regulations, coordinates an application for use, and provides authorization for federal government/agency use of the radio frequency (RF) spectrum is the National Telecommunications and Information Administration (NTIA). In this regard, the NTIA defines which RF spectrum is available for federal government use in the USA, and how it is to be used. The NTIA is a component of the United States (U.S.) Department of Commerce of the federal government. The significance of ITU regulations is that ITU approval is required for U.S. federal government/agency permission to use the RF spectrum outside of U.S. boundaries. All member nations have signed a treaty to do so. U.S. federal regulations for federal use of the RF spectrum are found in the Manual of Regulations and Procedures for Federal Radio Frequency Management, and extracts of the manual are found in what is known as the Table of Frequency Allocations. Nonfederal government and private sector use of the RF spectrum within the U.S. is regulated by the Federal Communications Commission (FCC). There is a need to control "unwanted emissions" (defined to include out-of-band emissions, which are those immediately adjacent to the necessary and allocated bandwidth, plus spurious emissions) to preclude interference to all other authorized users. This paper discusses the causes, effects, and mitigation of unwanted RF emissions to systems in adjacent spectra. Digital modulations are widely used in today's satellite communications. Commercial communications sector standards are covered for the most part worldwide by Digital Video Broadcast - Satellite (DVB-S) and digital satellite news gathering (DSNG) evolutions and the second generation of DVB-S (DVB-S2) standard

  17. SRF and RF systems for LEReC Linac

    SciTech Connect

    Belomestnykh, S.; Ben-Zvi, I.; Brutus, J. C.; Fedotov, A.; McIntyre, G.; Polizzo, S.; Smith, K.; Than, R.; Tuozzolo, J.; Veshcherevich, V.; Wu, Q.; Xiao, B.; Xu, W.; Zaltsman, A.

    2015-05-03

    The Low Energy RHIC electron Cooling (LEReC) is under development at BNL to improve RHIC luminosity at low energies. It will consist of a short electron linac and two cooling sections, one for blue and one for yellow rings. For the first stage of the project, LEReC-I, we will install a 704 MHz superconducting RF cavity and three normal conducting cavities operating at 9 MHz, 704 MHz and 2.1 GHz. The SRF cavity will boost the electron beam energy up to 2 MeV. The warm cavities will be used to correct the energy spread introduced in the SRF cavity. The paper describes layouts of the SRF and RF systems, their parameters and status.

  18. RF MEMS and Their Applications in NASA's Space Communication Systems

    NASA Technical Reports Server (NTRS)

    Williams, W. Daniel; Ponchak, George E.; Simons, Rainee N.; Zaman, Afroz; Kory, Carol; Wintucky, Edwin; Wilson, Jeffrey D.; Scardelletti, Maximilian; Lee, Richard; Nguyen, Hung

    2001-01-01

    Radio frequency (RF) and microwave communication systems rely on frequency, amplitude, and phase control circuits to efficiently use the available spectrum. Phase control circuits are required for electronically scanning phase array antennas that enable radiation pattern shaping, scanning, and hopping. Two types of phase shifters, which are the phase control circuits, are most often used. The first is comprised of two circuits with different phase characteristics such as two transmission lines of different lengths or a high pass and low pass filter and a switch that directs the RF power through one of the two circuits. Alternatively, a variable capacitor, or varactor, is used to change the effective electrical path length of a transmission line, which changes the phase characteristics. Filter banks are required for the diplexer at the front end of wide band communication satellites. These filters greatly increase the size and mass of the RF/microwave systems, but smaller diplexers may be made with a low loss varactor or a group of capacitors, a switch and an inductor.

  19. FinFET and UTBB for RF SOI communication systems

    NASA Astrophysics Data System (ADS)

    Raskin, Jean-Pierre

    2016-11-01

    Performance of RF integrated circuit (IC) is directly linked to the analog and high frequency characteristics of the transistors, the quality of the back-end of line process as well as the electromagnetic properties of the substrate. Thanks to the introduction of the trap-rich high-resistivity Silicon-on-Insulator (SOI) substrate on the market, the ICs requirements in term of linearity are fulfilled. Today partially depleted SOI MOSFET is the mainstream technology for RF SOI systems. Future generations of mobile communication systems will require transistors with better high frequency performance at lower power consumption. The advanced MOS transistors in competition are FinFET and Ultra Thin Body and Buried oxide (UTBB) SOI MOSFETs. Both devices have been intensively studied these last years. Most of the reported data concern their digital performance. In this paper, their analog/RF behavior is described and compared. Both show similar characteristics in terms of transconductance, Early voltage, voltage gain, self-heating issue but UTBB outperforms FinFET in terms of cutoff frequencies thanks to their relatively lower fringing parasitic capacitances.

  20. Rf power system for the chopper/buncher system on the NBS-Los Alamos RTM

    SciTech Connect

    Young, L.M.; Keffeler, D.R.

    1985-01-01

    The rf power system and its closed-loop feedback control for the racetrack microtron (RTM) chopper/buncher system are described. Measurements made on the response of the feedback system to external perturbations will also be reported.

  1. The Advanced Photon Source pulsed deflecting cavity RF system.

    SciTech Connect

    Cours, A.; DiMonte, N. P.; Smith, T. L.; Waldschmidt, G.

    2008-01-01

    The Advanced Photon Source Deflecting Cavity System for producing short X-ray pulses uses two multi-cell, S-band cavities to apply a deflecting voltage to the stored electron beam ahead of an undulator that supports a beamline utilizing picosecond X-rays. Two additional multi-cell cavities are then used to cancel out the perturbation and restore the electron beam to its nominal orbit. The pulsed rf system driving the deflecting cavities is described. Design tradeoffs are discussed with emphasis on topology considerations and digital control loops making use of sampling technology in a manner consistent with the present state of the art.

  2. RF H and CD systems for DEMO - Challenges and opportunities

    SciTech Connect

    Franke, T.; Wenninger, R.; Barbato, E.; Cardinali, A.; Cesario, R.; Mirizzi, F.; Tuccillo, A. A.; Ceccuzzi, S.; Eester, D. V.; Lerche, E.

    2014-02-12

    The aim of driving a sufficient amount of plasma current with an appropriate radial current density profile is considered as one of the key challenges for a tokamak fusion power plant in steady state operation. Furthermore, efficient heating to enable transition to regime of enhanced confinement and to achieve breakeven plasma temperatures as well as MHD control and plasma breakdown assistance are required. In the framework of the EFDA Power Plant Physics and Technology (PPPT) activities, the ability of the Electron cyclotron (EC), Ion Cyclotron (IC) and Lower Hybrid (LH) systems to fulfil these requirements, was studied for a demonstration fusion power plant (DEMO). As boundary condition, a 1D description of the plasma for a pulsed DEMO based on system code studies combined with transport analysis was developed. The predicted 1D plasma parameters were used to calculate the current drive (CD) efficiency of each system and eventually optimised it. As an example, the EC current drive efficiency could be increased strongly by top launch compared to equatorial launch at least by a factor of two. For the IC system, two possible windows of operation for standard and higher frequencies were highlighted, whereby again top launch leads to higher CD-efficiencies. The efficiencies predicted for DEMO for the RF current drive systems will be presented. Finally, gaps in the feasibility of RF systems under DEMO relevant conditions will be identified.

  3. High Gradient Operation with the CEBAF Upgrade RF Control System

    SciTech Connect

    J. Hovater; G. Davis; Hai Dong; Alicia Hofler; Lawrence King; John Musson; Tomasz Plawski

    2006-08-16

    The CEBAF Accelerator at Jefferson Lab is presently a 6 GeV five pass electron accelerator consisting of two superconducting linacs joined by independent magnetic transport arcs. Energy will be upgraded to 12 GeV with the addition of 10 new high gradient cryomodules (17+ MV/m). The higher gradients pose significant challenges beyond what the present analog low level RF (LLRF) control systems can handle reliably; therefore, a new LLRF control system is needed. A prototype system has been developed incorporating a large FPGA and using digital down and up conversion to minimize the need for analog components. The new system is more flexible and less susceptible to drifts and component nonlinearities. Because resonance control is critical to reach high gradients quickly, the new cryomodules will include a piezoelectric tuner for each cavity, and the LLRF controls must incorporate both feedback and feed-forward methods to achieve optimal resonance control performance. This paper discusses development of the new RF system, system performance for phase and amplitude stability and resonance control under Lorentz detuning measured during recent tests on a prototype cryomodule.

  4. Solid state power systems for DC and RF accelerators

    NASA Astrophysics Data System (ADS)

    Adler, R. J.; Richter-Sand, R. J.

    1999-06-01

    Modern accelerator applications require high average and peak powers—particularly RF accelerators and DC accelerators. In many of these applications, it is possible to replace tubes in the power systems with solid state power supplies. In this paper we outline work which we have performed in developing solid state pulsed and CW pulsed power systems for RF linacs and for DC accelerators. We have built and successfully tested a 125 kV, 2.5 MW peak, 60 kW average pulsed power system which is well suited to driving ion beam linacs. This system is modular, with 3 modules capable of driving a large Klystron. The system has been extensively tested with both resistive and fault loads. This type of power supply promises to be less than half as expensive as a conventional thyratron modulator, with considerably more flexibility in pulse duration. We have also powered our Nested High Voltage (NHV) accelerators with a solid state power supply using IGBTs. This type of supply is suitable for both NHV machines, and other Dynamitron style accelerators. Pulsed burst mode excitation of this type of power supply allows us to maintain 1 MV in the NHV accelerator with less than three hundred watts of idling power.

  5. Solid state power systems for DC and RF accelerators

    SciTech Connect

    Adler, R. J.; Richter-Sand, R. J.

    1999-06-10

    Modern accelerator applications require high average and peak powers - particularly RF accelerators and DC accelerators. In many of these applications, it is possible to replace tubes in the power systems with solid state power supplies. In this paper we outline work which we have performed in developing solid state pulsed and CW pulsed power systems for RF linacs and for DC accelerators. We have built and successfully tested a 125 kV, 2.5 MW peak, 60 kW average pulsed power system which is well suited to driving ion beam linacs. This system is modular, with 3 modules capable of driving a large Klystron. The system has been extensively tested with both resistive and fault loads. This type of power supply promises to be less than half as expensive as a conventional thyratron modulator, with considerably more flexibility in pulse duration. We have also powered our Nested High Voltage (NHV) accelerators with a solid state power supply using IGBTs. This type of supply is suitable for both NHV machines, and other Dynamitron style accelerators. Pulsed burst mode excitation of this type of power supply allows us to maintain 1 MV in the NHV accelerator with less than three hundred watts of idling power.

  6. Experimental Study of RF Energy Transfer System in Indoor Environment

    NASA Astrophysics Data System (ADS)

    Adami, S.-E.; Proynov, P. P.; Stark, B. H.; Hilton, G. S.; Craddock, I. J.

    2014-11-01

    This paper presents a multi-transmitter, 2.43 GHz Radio-Frequency (RF) wireless power transfer (WPT) system for powering on-body devices. It is shown that under typical indoor conditions, the received power range spans several orders of magnitude from microwatts to milliwatts. A body-worn dual-polarised rectenna (rectifying antenna) is presented, designed for situations where the dominant polarization is unpredictable, as is the case for the on-body sensors. Power management circuitry is demonstrated that optimally loads the rectenna even under highly intermittent conditions, and boosts the voltage to charge an on-board storage capacitor.

  7. Barrier RF system and applications in Main Injector

    SciTech Connect

    Chou, W.; Wildman, D.; Takagi, A.; Zheng, H.; /Caltech

    2005-05-01

    A novel broadband RF system--the barrier RF--has been designed, fabricated and installed in the Fermilab Main Injector (MI). It uses nanocrystal magnetic alloy called Finemet and high voltage fast MOSFET switches. The system delivers {+-}10 kV square pulses at 90 kHz. It can stack two proton batches injected from the Booster and squeeze them into the size of one so that the bunch intensity is increased. The high intensity beams have been successfully accelerated to 120 GeV with small losses. The problem of large longitudinal emittance growth is under investigation. A second system will be installed during the fall shutdown and be tested for the so-called fast stacking scheme to continuously stack up to 12 Booster batches in the MI. This system is also used for cleaning up the leaking-out dc beams from slip stacking to reduce beam loss. This work is part of the US-Japan collaborative agreement.

  8. rf power system for thrust measurements of a helicon plasma source

    SciTech Connect

    Kieckhafer, Alexander W.; Walker, Mitchell L. R.

    2010-07-15

    A rf power system has been developed, which allows the use of rf plasma devices in an electric propulsion test facility without excessive noise pollution in thruster diagnostics. Of particular importance are thrust stand measurements, which were previously impossible due to noise. Three major changes were made to the rf power system: first, the cable connection was changed from a balanced transmission line to an unbalanced coaxial line. Second, the rf power cabinet was placed remotely in order to reduce vibration-induced noise in the thrust stand. Finally, a relationship between transmission line length and rf was developed, which allows good transmission of rf power from the matching network to the helicon antenna. The modified system was tested on a thrust measurement stand and showed that rf power has no statistically significant contribution to the thrust stand measurement.

  9. A new RF window designed for high-power operation in an S-band LINAC RF system

    NASA Astrophysics Data System (ADS)

    Joo, Youngdo; Kim, Seung-Hwan; Hwang, Woonha; Ryu, Jiwan; Roh, Sungjoo

    2016-09-01

    A new RF window is designed for high-power operation at the Pohang Light Source-II (PLSII) S-band linear accelerator (LINAC) RF system. In order to reduce the strength of the electric field component perpendicular to the ceramic disk, which is commonly known as the main cause of most discharge breakdowns in ceramic disk, we replace the pill-box type cavity in the conventional RF window with an overmoded cavity. The overmoded cavity is coupled with input and output waveguides through dual side-wall coupling irises to reduce the electric field strength at the iris and the number of possible mode competitions. The finite-difference time-domain (FDTD) simulation, CST MWS, was used in the design process. The simulated maximum electric field component perpendicular to the ceramic for the new RF window is reduced by an order of magnitude compared with taht for the conventional RF window, which holds promise for stable high-power operation.

  10. Recent Advances in RF Pulse Compressor Systems at SLAC

    NASA Astrophysics Data System (ADS)

    Tantawi, Sami G.; Nantista, Christopher D.

    2003-12-01

    We will review the design of the dual-mode X-band rf system proposed for the Next Linear Collider (NLC). Recent experimental data are presented. The system is to produce 400 ns pulses with power levels up to 600 MW. A proof-of-principle experiment is being constructed at SLAC. Four 50 MW klystrons will power a fully dual-moded resonance delay line pulse compression system. Both the transfer line and the delay lines are dual-moded. The modes carried by the transfer line are controlled by the rf phases of the different klystrons. The modes in the delay lines are controlled by a set of mode converters at the input and the end of each delay line. By manipulating the modes in the transfer line, one can achieve either no pulse compression or a pulse compression ratio of 4. The total output power will be 200 MW for 1.6 microseconds or 600 MW for 400 nanoseconds.

  11. RF System Modeling for the CEBAF Energy Upgrade

    SciTech Connect

    Tomasz Plawski, J. Hovater

    2009-05-01

    An RF system model, based on MATLAB/SIMULINK, has been developed for analyzing the basic characteristics of the low level RF (LLRF) control system being designed for the CEBAF 12 GeV Energy Upgrade. In our model, a typical passband cavity representation is simplified to in-phase and quadrature (I&Q) components. Lorentz Force and microphonic detuning are incorporated as a new quadrature carrier frequency (frequency modulation). Beam is also represented as in-phase and quadrature components and superpositioned with the cavity field vector. Signals pass through two low pass filters, where the cutoff frequency is equal to half of the cavity bandwidth, then they are demodulated using the same detuning frequency. Because only baseband I&Q signals are calculated, the simulation process is very fast when compared to other controller-cavity models. During the design process we successfully analyzed gain requirements vs. field stability for different superconducting cavity microphonic backgrounds and Lorentz Force coefficients. Moreover, we were able to evaluate different types of a LLRF system’s control algorithm: GDR (Generator Driven Resonator) and SEL (Self Excited Loop) [1] as well as klystron power requirements for different cavities and beam loads.

  12. Controlling satellite communication system unwanted emissions in congested RF spectrum

    NASA Astrophysics Data System (ADS)

    Olsen, Donald; Heymann, Roger

    2007-09-01

    The International Telecommunication Union (ITU), a United Nations (UN) agency, is the agency that, under an international treaty, sets radio spectrum usage regulations among member nations. Within the United States of America (USA), the organization that sets regulations, coordinates an application for use, and provides authorization for federal government/agency use of the radio frequency (RF) spectrum is the National Telecommunications and Information Administration (NTIA). In this regard, the NTIA defines which RF spectrum is available for federal government use in the USA, and how it is to be used. The NTIA is a component of the United States (U.S.) Department of Commerce of the federal government. The significance of ITU regulations is that ITU approval is required for U.S. federal government/agency permission to use the RF spectrum outside of U.S. boundaries. All member nations have signed a treaty to do so. U.S. federal regulations for federal use of the RF spectrum are found in the Manual of Regulations and Procedures for Federal Radio Frequency Management, and extracts of the manual are found in what is known as the Table of Frequency Allocations. Nonfederal government and private sector use of the RF spectrum within the U.S. is regulated by the Federal Communications Commission (FCC). There is a need to control "unwanted emissions" (defined to include out-of-band emissions, which are those immediately adjacent to the necessary and allocated bandwidth, plus spurious emissions) to preclude interference to all other authorized users. This paper discusses the causes, effects, and mitigation of unwanted RF emissions to systems in adjacent spectra. Digital modulations are widely used in today's satellite communications. Commercial communications sector standards are covered for the most part worldwide by Digital Video Broadcast - Satellite (DVB-S) and digital satellite news gathering (DSNG) evolutions and the second generation of DVB-S (DVB-S2) standard

  13. Coordination Chemistry of Diiodine and Implications for the Oxidation Capacity of the Synergistic Ag(+) /X2 (X=Cl, Br, I) System.

    PubMed

    Malinowski, Przemysław J; Himmel, Daniel; Krossing, Ingo

    2016-08-01

    The synergistic Ag(+) /X2 system (X=Cl, Br, I) is a very strong, but ill-defined oxidant-more powerful than X2 or Ag(+) alone. Intermediates for its action may include [Agm (X2 )n ](m+) complexes. Here, we report on an unexpectedly variable coordination chemistry of diiodine towards this direction: (A)Ag-I2 -Ag(A), [Ag2 (I2 )4 ](2+) (A(-) )2 and [Ag2 (I2 )6 ](2+) (A(-) )2 ⋅(I2 )x≈0.65 form by reaction of Ag(A) (A=Al(OR(F) )4 ; R(F) =C(CF3 )3 ) with diiodine (single crystal/powder XRD, Raman spectra and quantum-mechanical calculations). The molecular (A)Ag-I2 -Ag(A) is ideally set up to act as a 2 e(-) oxidant with stoichiometric formation of 2 AgI and 2 A(-) . Preliminary reactivity tests proved this (A)Ag-I2 -Ag(A) starting material to oxidize n-C5 H12 , C3 H8 , CH2 Cl2 , P4 or S8 at room temperature. A rough estimate of its electron affinity places it amongst very strong oxidizers like MF6 (M=4d metals). This suggests that (A)Ag-I2 -Ag(A) will serve as an easily in bulk accessible, well-defined, and very potent oxidant with multiple applications. PMID:27411163

  14. LCLS-II high power RF system overview and progress

    SciTech Connect

    Yeremian, Anahid Dian

    2015-10-07

    A second X-ray free electron laser facility, LCLS-II, will be constructed at SLAC. LCLS-II is based on a 1.3 GHz, 4 GeV, continuous-wave (CW) superconducting linear accelerator, to be installed in the first kilometer of the SLAC tunnel. Multiple types of high power RF (HPRF) sources will be used to power different systems on LCLS-II. The main 1.3 GHz linac will be powered by 280 1.3 GHz, 3.8 kW solid state amplifier (SSA) sources. The normal conducting buncher in the injector will use four more SSAs identical to the linac SSAs but run at 2 kW. Two 185.7 MHz, 60 kW sources will power the photocathode dual-feed RF gun. A third harmonic linac section, included for linearizing the bunch energy spread before the first bunch compressor, will require sixteen 3.9 GHz sources at about 1 kW CW. A description and an update on all the HPRF sources of LCLS-II and their implementation is the subject of this paper.

  15. The AGS Booster beam loss monitor system

    SciTech Connect

    Beadle, E.R.; Bennett, G.W.; Witkover, R.L.

    1991-01-01

    A beam loss monitor system has been developed for the Brookhaven National Laboratory Booster accelerator, and is designed for use with intensities of up to 1.5 {times} 10{sup 13} protons and carbon to gold ions at 50-3 {times} 10{sup 9} ions per pulse. This system is a significant advance over the present AGS system by improving the sensitivity, dynamic range, and data acquisition. In addition to the large dynamic range achievable, it is adaptively shifted when high losses are detected. The system uses up to 80 argon filled ion chambers as detectors, as well as newly designed electronics for processing and digitizing detector outputs. The hardware simultaneously integrates each detector output, interfaces to the beam interrupt systems, and digitizes all 80 channels to 21 bits at 170 KHz. This paper discuses the design, construction, and operation of the system. 4 refs., 2 figs.

  16. Active and Passive RF Components for High-Power Systems

    NASA Astrophysics Data System (ADS)

    Tantawi, Sami G.; Nantista, Christopher D.

    2002-08-01

    In recent years, R&D for pulse compression and power distribution systems for the Next Linear Collider has led to the invention of many novel rf components, some of which must handle up to 600 MW of pulsed power at X-band. These include passive waveguide components, active switch designs, and non-reciprocal devices. Among the former is a class of multi-moded, highly efficient rf components based on planar geometries with overmoded rectangular ports. Multi-moding allows us, by means of input phasing, to direct power to different locations through the same waveguide. Planar symmetry allows the height to be increased to improve power handling capacity. Features that invite breakdown, such as coupling slots, irises and H-plane septa, are avoided. This class includes hybrids, directional couplers, an eight-port superhybrid/dual-mode launcher, a mode-selective extractor, mode-preserving bends, a rectangular mode converter, and mode-mixers. We are able to utilize such rectangular waveguide components in systems incorporating low-loss, circular waveguide delay lines by means of specially designed tapers that efficiently transform multiple rectangular waveguide modes into their corresponding circular waveguide modes, specifically TE10 and TE20 into circular TE11 and TE01. These extremely compact tapers can replace well-known mode converters such as the Marie type. Another component, a reflective TE01-TE02 mode converter in circular waveguide, allows us to double the delay in reflective or resonant delay lines. Ideas for multi-megawatt active components, such as switches, have also been pursued. Power-handling capacity for these is increased by making them also highly overmoded. We present a design methodology for active rf magnetic components which are suitable for pulse compression systems of future X-band linear colliders. We also present an active switch based on a PIN diode array. This component comprises an array of active elements arranged so that the electric fields

  17. MuRF1-dependent regulation of systemic carbohydrate metabolism as revealed from transgenic mouse studies.

    PubMed

    Hirner, Stephanie; Krohne, Christian; Schuster, Alexander; Hoffmann, Sigrid; Witt, Stephanie; Erber, Ralf; Sticht, Carsten; Gasch, Alexander; Labeit, Siegfried; Labeit, Dittmar

    2008-06-13

    Under various pathophysiological muscle-wasting conditions, such as diabetes and starvation, a family of ubiquitin ligases, including muscle-specific RING-finger protein 1 (MuRF1), are induced to target muscle proteins for degradation via ubiquitination. We have generated transgenic mouse lines over-expressing MuRF1 in a skeletal muscle-specific fashion (MuRF1-TG mice) in an attempt to identify the in vivo targets of MuRF1. MuRF1-TG lines were viable, had normal fertility and normal muscle weights at eight weeks of age. Comparison of quadriceps from MuRF1-TG and wild type mice did not reveal elevated multi-ubiquitination of myosin as observed in human patients with muscle wasting. Instead, MuRF1-TG mice expressed lower levels of pyruvate dehydrogenase (PDH), a mitochondrial key enzyme in charge of glycolysis, and of its regulator PDK2. Furthermore, yeast two-hybrid interaction studies demonstrated the interaction of MuRF1 with PDH, PDK2, PDK4, PKM2 (all participating in glycolysis) and with phosphorylase beta (PYGM) and glycogenin (both regulating glycogen metabolism). Consistent with the idea that MuRF1 may regulate carbohydrate metabolism, MuRF1-TG mice had twofold elevated insulin blood levels and lower hepatic glycogen contents. To further examine MuRF1's role for systemic carbohydrate regulation, we performed glucose tolerance tests (GTT) in wild type and MuRF1-TG mice. During GTT, MuRF1-TG mice developed striking hyperinsulinaemia and hepatic glycogen stores, that were depleted at basal levels, became rapidly replenished. Taken together, our data demonstrate that MuRF1 expression in skeletal muscle re-directs glycogen synthesis to the liver and stimulates pancreatic insulin secretion, thereby providing a regulatory feedback loop that connects skeletal muscle metabolism with the liver and the pancreas during metabolic stress. PMID:18468620

  18. RF Sounding: A System for Generating Sounds from Spectral Analysis

    NASA Astrophysics Data System (ADS)

    Graziosi, Fabio; Rinaldi, Claudia; Tarquini, Francesco

    In this paper we present RF Sounding, an open space installation which comprises both artistic and technological innovations. The aim of this project is to provide the user entering a specifically defined area, with awareness of radio frequency signals characterizing the cellular networks band. Indeed, radio signals are shifted, with proper elaboration, to the audible band and the result is spread all over the specific area through a certain number of loudspeakers. The system produces different reactions depending on the communication phase (e.g. initial handshake procedure, reception or initiation of a call, etc.). Moreover, the sound produced after translation of signals to the audible band, is assumed to be spatialized as a function of user movement; localization is indeed achieved through a wireless sensor network that is installed in the defined area.

  19. Some Aspects of the Moscow Meson Factory DTL RF System Tuning

    NASA Astrophysics Data System (ADS)

    Kvasha, A. I.

    1997-05-01

    In this paper the consideration of RF system tuning is ot limited by problems of getting of the demanded level of the RF power in a RF load only as it is supposed that the RF system includes in its the full equipment which provides an acceleration of charge particles i.e. a tank, a coupling loop, a feeder line and RF channel with RF amplifiers and power supply. The simple connection of separate parts of this equipment with each other (after their prelemenary autonomous tuning) can sometimes lead to undesirable results such as: -tank detuning due to an interaction between a fast automatic phase control system (APCS) and automatic frequency control system; - a deterioration of an accelerating field stabilization due to an interaction between a fast APCS and a fast automatic amplitude control system; - an overvoltage in the network of the output RF amplifier H/V supply; - an overvoltage in the anode-grid cavity of the RF output amplifier because of "discharge" of an energy, stored in the tank during an RF pulse. Some proposals verified at the MMF DTL which partly exclude above- mentioned undesirable effects are discussed.

  20. Development of an RF Conditioning System for Charged-Particle Accelerators

    SciTech Connect

    Kang, Yoon W; Howlader, Mostofa; Shajedul Hasan, Dr. S. M.

    2008-01-01

    Charged-particle accelerators use various vacuum windows on their accelerating radio-frequency (RF) cavities to throughput very high RF power. Before being placed on the cavities, the windows should be cleaned, baked, and fully RF conditioned to prevent a poor vacuum from outgassing, as well as other forms of contamination. An example is the coaxial fundamental power coupler (FPC) with an annular alumina ceramic window for each of the 81 superconducting RF cavities in the Spallation Neutron Source (SNS) linear accelerator. The FPCs needed to be tested up to 650-kW peak in a traveling wave and 2.6 MW with standing wave peaks in 1.3 and 60 pulses/s at 805 MHz. In this paper, an Experimental-Physics-and-Industrial-Control-System-based RF conditioning system for the SNS RF test facility is presented. This paper summarizes the hardware and software design strategies, provides the results obtained, and describes the future research scope.

  1. RF system models for the CERN Large Hadron Collider with application to longitudinal dynamics

    SciTech Connect

    Mastorides, T.; Rivetta, C.; Fox, J.D.; Winkle, D.Van; Baudrenghien, P.; /CERN

    2011-03-03

    The LHC RF station-beam interaction strongly influences the longitudinal beam dynamics, both single bunch and collective effects. Non-linearities and noise generated within the Radio Frequency (RF) accelerating system interact with the beam and contribute to beam motion and longitudinal emittance blowup. Thus, the noise power spectrum of the RF accelerating voltage strongly affects the longitudinal beam distribution. Furthermore, the coupled-bunch instabilities are also directly affected by the RF components and the configuration of the Low Level RF (LLRF) feedback loops. In this work we present a formalism relating the longitudinal beam dynamics with the RF system configurations, an estimation of collective effects stability margins, and an evaluation of longitudinal sensitivity to various LLRF parameters and configurations.

  2. RF Lens-Embedded Massive MIMO Systems: Fabrication Issues and Codebook Design

    NASA Astrophysics Data System (ADS)

    Kwon, Taehoon; Lim, Yeon-Geun; Min, Byung-Wook; Chae, Chan-Byoung

    2016-07-01

    In this paper, we investigate a radio frequency (RF) lens-embedded massive multiple-input multiple-output (MIMO) system and evaluate the system performance of limited feedback by utilizing a technique for generating a suitable codebook for the system. We fabricate an RF lens that operates on a 77 GHz (mmWave) band. Experimental results show a proper value of amplitude gain and an appropriate focusing property. In addition, using a simple numerical technique--beam propagation method (BPM)--we estimate the power profile of the RF lens and verify its accordance with experimental results. We also design a codebook--multi-variance codebook quantization (MVCQ)--for limited feedback by considering the characteristics of the RF lens antenna for massive MIMO systems. Numerical results confirm that the proposed system shows significant performance enhancement over a conventional massive MIMO system without an RF lens.

  3. Using a double-frequency RF system to facilitate on-axis beam accumulation in a storage ring

    NASA Astrophysics Data System (ADS)

    Jiang, B. C.; Zhao, Z. T.; Tian, S. Q.; Zhang, M. Z.; Zhang, Q. L.

    2016-04-01

    An on-axis injection scheme using a double-frequency RF system in a storage ring with small dynamic aperture is proposed. By altering RF voltages, empty RF buckets can be created which will be used for on-axis injection. After bunches are injected, a reverse RF voltage altering process is performed and the injected bunches can be longitudinally dumped to the main RF buckets. The scheme allows reaping the advantages of the on-axis injection while still performing accumulation.

  4. Balanced-line rf electrode system for use in rf ground heating to recover oil from oil shale

    SciTech Connect

    Edelstein, W.A.; Vinegar, H.J.; Chiafu Hsu; Mueller, O.M.

    1993-08-17

    A system is described for extracting oil in-situ from a hydrocarbon bearing layer below a surface layer comprising: (a) a master oscillator for producing a fundamental frequency; (b) a plurality of heating sources, each comprising: radiofrequency (RF) producing means for providing a radiofrequency excitation signal based upon the fundamental frequency, a coaxial line coupled to the RF producing means for passing the radiofrequency signal through said surface layer without substantial loss of power; a conductive electrode located in the hydrocarbon bearing layer having a length related to the radiofrequency signal and adapted for radiating energy into said hydrocarbon bearing layer for causing shade oil to be extracted; a plurality of matching elements, each matching element coupled, respectively, between each respective electrode and a respective coaxial line for maximizing radiation emitted by the electrodes when they receive the radiofrequency signal; and (c) a plurality of producer wells adapted for collecting the extracted shale oil.

  5. RF Head Coil Design with Improved RF Magnetic Near-Fields Uniformity for Magnetic Resonance Imaging (MRI) Systems

    PubMed Central

    Sohn, Sung-Min; DelaBarre, Lance; Gopinath, Anand; Vaughan, John Thomas

    2015-01-01

    Higher magnetic field strength in magnetic resonance imaging (MRI) systems offers higher signal-to-noise ratio (SNR), contrast, and spatial resolution in MR images. However, the wavelength in ultra-high fields (7 tesla and beyond) becomes shorter than the human body at the Larmor frequency with increasing static magnetic field (B0) of MRI system. At short wavelengths, interference effect appears resulting in non- uniformity of the RF magnetic near-field (B1) over the subject and MR images may have spatially anomalous contrast. The B1 near-field generated by the transverse electromagnetic (TEM) RF coil’s microstrip line element has a maximum near the center of its length and falls off towards both ends. In this study, a double trapezoidal shaped microstrip transmission line element is proposed to obtain uniform B1 field distribution by gradual impedance variation. Two multi-channel RF head coils with uniform and trapezoidal shape elements were built and tested with a phantom at 7T MRI scanner for comparison. The simulation and experimental results show stronger and more uniform B1+ near-field with the trapezoidal shape. PMID:25892746

  6. Communication methods, systems, apparatus, and devices involving RF tag registration

    DOEpatents

    Burghard, Brion J.; Skorpik, James R.

    2008-04-22

    One technique of the present invention includes a number of Radio Frequency (RF) tags that each have a different identifier. Information is broadcast to the tags from an RF tag interrogator. This information corresponds to a maximum quantity of tag response time slots that are available. This maximum quantity may be less than the total number of tags. The tags each select one of the time slots as a function of the information and a random number provided by each respective tag. The different identifiers are transmitted to the interrogator from at least a subset of the RF tags.

  7. Commissioning of the LHC Low Level RF System Remote Configuration Tools

    SciTech Connect

    Van Winkle, Daniel; Fox, John; Mastorides, Themis; Rivetta, Claudio; Baudrenghien, Philippe; Butterworth, Andrew; Molendijk, John; /CERN

    2010-08-26

    The LHC Low Level RF system (LLRF) is a complex multi-loop system used to regulate the superconductive cavity gap voltage as well as to reduce the impedance presented by RF stations to the beam. The RF system can have a profound impact on the stability of the beam; a mis-configured RF system has the potential of causing longitudinal instabilities, beam diffusion and beam loss. To configure the RF station for operation, a set of parameters in the LLRF multi-loop system have to be defined. Initial system commissioning as well as ongoing operation requires a consistent method of computer based remote measurement and model-based design of each RF station feedback system. This paper describes the suite of Matlab tools used for configuring the LHC RF system during the start up in Nov2009-Feb2010. We present a brief overview of the tool, examples of commissioning results, and basics of the model-based design algorithms. This work complements our previous presentation, where the algorithms and methodology followed in the tools were described.

  8. Arc Detection and Interlock Module for the PEP II Low Level RF System

    SciTech Connect

    Tighe, R.; /SLAC

    2011-08-31

    A new arc detection and interlock generating module for the SLAC PEP-II low-level RF VXI-based system has been developed. The system is required to turn off the RF drive and high voltage power supply in the event of arcing in the cavity windows, klystron window, or circulator. Infrared photodiodes receive arc signals through radiation resistant optical fibers. Gain and bandwidth are selectable for each channel to allow tailoring response. The module also responds to interlock requests from other modules in the VXI system and communicates with the programmable logic controller (PLC) responsible for much of the low-level RF system's interlock functionality.

  9. Accurate measurement of RF exposure from emerging wireless communication systems

    NASA Astrophysics Data System (ADS)

    Letertre, Thierry; Monebhurrun, Vikass; Toffano, Zeno

    2013-04-01

    Isotropic broadband probes or spectrum analyzers (SAs) may be used for the measurement of rapidly varying electromagnetic fields generated by emerging wireless communication systems. In this paper this problematic is investigated by comparing the responses measured by two different isotropic broadband probes typically used to perform electric field (E-field) evaluations. The broadband probes are submitted to signals with variable duty cycles (DC) and crest factors (CF) either with or without Orthogonal Frequency Division Multiplexing (OFDM) modulation but with the same root-mean-square (RMS) power. The two probes do not provide accurate enough results for deterministic signals such as Worldwide Interoperability for Microwave Access (WIMAX) or Long Term Evolution (LTE) as well as for non-deterministic signals such as Wireless Fidelity (WiFi). The legacy measurement protocols should be adapted to cope for the emerging wireless communication technologies based on the OFDM modulation scheme. This is not easily achieved except when the statistics of the RF emission are well known. In this case the measurement errors are shown to be systematic and a correction factor or calibration can be applied to obtain a good approximation of the total RMS power.

  10. Commissioning and Early Operation Experience of the NSLS-II Storage Ring RF System

    SciTech Connect

    Gao, F.; Rose, J.; Cupolo, J.; Dilgen, T.; Rose, B.; Gash, W.; Ravindranath, V.; Yeddulla, M.; Papu, J.; Davila, P.; Holub, B.; Tagger, J.; Sikora, R.; Ramirez, G.; Kulpin, J.

    2015-05-03

    The National Synchrotron Light Source II (NSLS-II) is a 3 GeV electron X-ray user facility commissioned in 2014. The storage ring RF system, essential for replenishing energy loss per turn of the electrons, consists of digital low level RF controllers, 310 kW CW klystron transmitters, CESR-B type superconducting cavities, as well as a supporting cryogenic system. Here we will report on RF commissioning and early operation experience of the system for beam current up to 200mA.

  11. High-Power Multimode X-Band RF Pulse Compression System for Future Linear Colliders

    SciTech Connect

    Tantawi, S.G.; Nantista, C.D.; Dolgashev, V.A.; Pearson, C.; Nelson, J.; Jobe, K.; Chan, J.; Fant, K.; Frisch, J.; Atkinson, D.; /LLNL, Livermore

    2005-08-10

    We present a multimode X-band rf pulse compression system suitable for a TeV-scale electron-positron linear collider such as the Next Linear Collider (NLC). The NLC main linac operating frequency is 11.424 GHz. A single NLC rf unit is required to produce 400 ns pulses with 475 MW of peak power. Each rf unit should power approximately 5 m of accelerator structures. The rf unit design consists of two 75 MW klystrons and a dual-moded resonant-delay-line pulse compression system that produces a flat output pulse. The pulse compression system components are all overmoded, and most components are designed to operate with two modes. This approach allows high-power-handling capability while maintaining a compact, inexpensive system. We detail the design of this system and present experimental cold test results. We describe the design and performance of various components. The high-power testing of the system is verified using four 50 MW solenoid-focused klystrons run off a common 400 kV solid-state modulator. The system has produced 400 ns rf pulses of greater than 500 MW. We present the layout of our system, which includes a dual-moded transmission waveguide system and a dual-moded resonant line (SLED-II) pulse compression system. We also present data on the processing and operation of this system, which has set high-power records in coherent and phase controlled pulsed rf.

  12. High-power multimode X-band rf pulse compression system for future linear colliders

    NASA Astrophysics Data System (ADS)

    Tantawi, Sami G.; Nantista, Christopher D.; Dolgashev, Valery A.; Pearson, Chris; Nelson, Janice; Jobe, Keith; Chan, Jose; Fant, Karen; Frisch, Josef; Atkinson, Dennis

    2005-04-01

    We present a multimode X-band rf pulse compression system suitable for a TeV-scale electron-positron linear collider such as the Next Linear Collider (NLC). The NLC main linac operating frequency is 11.424 GHz. A single NLC rf unit is required to produce 400 ns pulses with 475 MW of peak power. Each rf unit should power approximately 5 m of accelerator structures. The rf unit design consists of two 75 MW klystrons and a dual-moded resonant-delay-line pulse compression system that produces a flat output pulse. The pulse compression system components are all overmoded, and most components are designed to operate with two modes. This approach allows high-power-handling capability while maintaining a compact, inexpensive system. We detail the design of this system and present experimental cold test results. We describe the design and performance of various components. The high-power testing of the system is verified using four 50 MW solenoid-focused klystrons run off a common 400 kV solid-state modulator. The system has produced 400 ns rf pulses of greater than 500 MW. We present the layout of our system, which includes a dual-moded transmission waveguide system and a dual-moded resonant line (SLED-II) pulse compression system. We also present data on the processing and operation of this system, which has set high-power records in coherent and phase controlled pulsed rf.

  13. Reliability and availability considerations in the RF systems of ATW-class accelerators

    NASA Astrophysics Data System (ADS)

    Tallerico, Paul J.; Lynch, Michael T.; Lawrence, George

    1995-09-01

    In an RF-driven, ion accelerator for waste transmutation or nuclear material production, the overall availability is perhaps the most important specification. The synchronism requirements in an ion accelerator, as contrasted to an electron accelerator, cause a failure of an RF source to have a greater consequence. These large machines also are major capital investments, so the availability determines the return on this capital. RF system design methods to insure a high availability without paying a serious cost penalty are the subject of this paper. The overall availability goal in our present designs is 75% for the entire ATW complex, and from 25 to 35% of the unavailability is allocated to the RF system, since it is one of the most complicated subsystems in the complex. The allowed down time for the RF system (including the linac and all other subsystems) is then only 7 to 9% of the operating time per year, or as little as 613 hours per year, for continuous operation. Since large accelerators consume large amounts of electrical power, excellent efficiency is also required with the excellent availability. The availability also influences the sizes of the RF components: smaller components may fail and yet the accelerator may still meet all specifications. Larger components are also attractive, since the cost of an RF system usually increases as the square root of the number of RF systems utilized. In some cases, there is a reliability penalty that accompanies the cost savings from using larger components. We discuss these factors, and present an availability model that allows one to examine these trade offs, and make rational choices in the RF and accelerator system designs.

  14. High power RF system for transverse deflecting structure XFEL TDS INJ

    NASA Astrophysics Data System (ADS)

    Volobuev, E. N.; Zavadtsev, A. A.; Zavadtsev, D. A.; Smirnov, A. J.; Sobenin, N. P.; Churanov, D. V.

    2016-09-01

    The high power RF system (HPRF) is designed for RF feeding of the transverse deflecting structure of the transverse deflecting system XFEL TDS System INJ of the European X-ray Free Electron Laser. The HPRF system includes klystron, waveguide ceramic windows, directional couplers, waveguide vacuum units, spark detector and waveguide line. Operating frequency is 2997.2 MHz. Peak input power is up to 3 MW. The HPRF system has been developed, manufactured and assembled in the XFEL Injector building. The total length of the waveguide line is 55 m from the klystron at the -5 floor to the transverse deflecting structure at the -7 floor. All designed RF parameters have been obtained experimentally at low RF power level.

  15. Precision 0.5 GW X-band rf system for advanced Compton scattering source

    NASA Astrophysics Data System (ADS)

    Chu, T. S.; Anderson, G.; Gibson, D.; Hartemann, F. V.; Barty, C. P. J.; Vlieks, A.; Tantawi, S.; Jongewaard, E.; Anderson, S. G.

    2009-11-01

    A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW, 1.5 msec pulses, will be the main high power RF sources for the system. These klystrons will be powered by state of the art solid-state high voltage modulators. A RF pulse compressor, similar to the SLED II pulse compressor, will compress the klystron output pulse with a power gain factor of five. This will give us 500 MW (0.5 GW) at output of the compressor. The compressed pulse will then be distributed to the RF gun and to the LINAC with specific phase and amplitude control points to allow for parameter control during operation. This high power RF system is being designed and constructed. In this paper, we will present the design, layout, and status of this RF system.

  16. RF Telemetry System for an Implantable Bio-MEMS Sensor

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Hall, David G.; Miranda, Felix A.

    2004-01-01

    In this paper, a novel miniature inductor and a pick-up antenna for contact less powering and RF telemetry from implantable bio-MEMS sensors are presented. The design of the inductor and the pick-up antenna are discussed. In addition, the measured characteristics at the design frequency of 330 MHz have been shown.

  17. Electrical conductivity of a system of Ag2SO4:AgI eutectic added to 30Li2SO4:70Ag2SO4

    NASA Astrophysics Data System (ADS)

    Chandrayan, V. R.; Tejpal, A.; Singh, K.

    1989-10-01

    The electrical conductivity of rapidly quenched specimens of 48Ag2SO4:52AgI eutectic added to 30Li2SO4:70Ag2SO4 has been measured as a function of frequency and temperature. The results show a significant enhancement in the conductivity of the 30Li2SO4:70Ag2SO4 system with a maximum value at 12.5 mol. pct eutectic. This phenomenon is explained in terms of the dispersive nature of the fine eutectic crystallites in the crystalline matrix of the Li2SO4:Ag2SO4 system.

  18. Commissioning and Early Operation for the NSLS-II Booster RF System

    SciTech Connect

    Marques, C.; Cupolo, J.; Davila, P.; Gao, F.; Goel, A.; Holub, B.; Kulpin, J.; McDonald, K.; Oliva, J.; Papu, J.; Ramirez, G.; Rose, J.; Sikora, R.; Sorrentino, C.; Towne, N.

    2015-05-03

    The National Synchrotron Light Source II (NSLS-II) at Brookhaven National Laboratory (BNL) is a third generation 3GeV, 500mA synchrotron light source. We discuss the booster synchrotron RF system responsible for providing power to accelerate an electron beam from 200MeV to 3GeV. The RF system design and construction are complete and is currently in the operational phase of the NSLS-II project. Preliminary operational data is also discussed.

  19. Some issues on the RF system in the 3 GeV Fermilab pre-booster

    SciTech Connect

    Ng, K. Y.

    1998-06-01

    Some issues are presented on the rf system in the future Fermilab prebooster, which accelerates 4 bunches each containing 0.25 x 10{sub 14} protons from 1 to 3 GeV kinetic energy. The problem of beam loading is discussed. The proposal of having a non-tunable fixed-frequency rf system is investigated. Robinson's criteria for phase stability are checked and possible Robinson instability growth is computed.

  20. Design of RF Systems for the RTD Mission VASIMR

    SciTech Connect

    Baity, F.W.; Barber, G.C.; Carter, M.D.; Chang-Diaz, F.R.; Goulding, R.H.; McCaskill, G.E.; Sparks, D.O.; Squire, J.P.

    1999-04-12

    The first flight test of the variable specific impulse magnetoplasma rocket (VASIMR) is tentatively scheduled for the Radiation and Technology Demonstration (RTD) in 2003. This mission to map the radiation environment out to several earth radii will employ both a Hall thruster and a VASIMR during its six months duration, beginning from low earth orbit. The mission will be powered by a solar array providing 12 kW of direct current electricity at 50 V. The VASIMR utilizes radiofrequency (RF) power both to generate a high-density plasma in a helicon source and to accelerate the plasma ions to high velocity by ion cyclotron resonance heating (ICRH). The VASIMR concept is being developed by the National Aeronautics and Space Administration (NASA) in collaboration with national laboratories and universities. Prototype plasma sources, RF amplifiers, and antennas are being developed in the experimental facilities of the Advanced Space Propulsion Laboratory (ASPL).

  1. Model based controls and the AGS booster controls system architecture

    SciTech Connect

    Casella, R.A.

    1987-08-18

    The Heavy Ion Transfer Line used to inject heavy ions created at the Tandem Van de Graaff into the Alternating Gradient Synchrotron (AGS) is briefly discussed, particularly as regards its control system. (LEW)

  2. Rf feedback free electron laser

    DOEpatents

    Brau, C.A.; Swenson, D.A.; Boyd, T.J. Jr.

    1979-11-02

    A free electron laser system and electron beam system for a free electron laser are provided which use rf feedback to enhance efficiency. Rf energy is extracted from an electron beam by decelerating cavities and returned to accelerating cavities using rf returns such as rf waveguides, rf feedthroughs, etc. This rf energy is added to rf klystron energy to lower the required input energy and thereby enhance energy efficiency of the system.

  3. Rf Feedback free electron laser

    DOEpatents

    Brau, Charles A.; Swenson, Donald A.; Boyd, Jr., Thomas J.

    1981-01-01

    A free electron laser system and electron beam system for a free electron laser which use rf feedback to enhance efficiency. Rf energy is extracted from an electron beam by decelerating cavities and returned to accelerating cavities using rf returns such as rf waveguides, rf feedthroughs, etc. This rf energy is added to rf klystron energy to lower the required input energy and thereby enhance energy efficiency of the system.

  4. Fiber optics as an rf transmission medium in cellular telephone systems

    NASA Astrophysics Data System (ADS)

    Jakubowski, Ronald J.

    1996-01-01

    Fiber optics has become an important medium in the development of worldwide cellular system microcell and remote antenna applications. Several products are available which take advantage of single mode 1310 and 1550 nm fiber optic transmission and its low loss and relative ease of installation. This paper presents a brief history of RF transmission technology, summarizes the technical aspects of the RF to light conversion, and describes the Allen Telecom fiber-based microcell and active antenna products while presenting examples of applications.

  5. Integrated Inductors for RF Transmitters in CMOS/MEMS Smart Microsensor Systems

    PubMed Central

    Kim, Jong-Wan; Takao, Hidekuni; Sawada, Kazuaki; Ishida, Makoto

    2007-01-01

    This paper presents the integration of an inductor by complementary metal-oxide-semiconductor (CMOS) compatible processes for integrated smart microsensor systems that have been developed to monitor the motion and vital signs of humans in various environments. Integration of radio frequency transmitter (RF) technology with complementary metal-oxide-semiconductor/micro electro mechanical systems (CMOS/MEMS) microsensors is required to realize the wireless smart microsensors system. The essential RF components such as a voltage controlled RF-CMOS oscillator (VCO), spiral inductors for an LC resonator and an integrated antenna have been fabricated and evaluated experimentally. The fabricated RF transmitter and integrated antenna were packaged with subminiature series A (SMA) connectors, respectively. For the impedance (50 Ω) matching, a bonding wire type inductor was developed. In this paper, the design and fabrication of the bonding wire inductor for impedance matching is described. Integrated techniques for the RF transmitter by CMOS compatible processes have been successfully developed. After matching by inserting the bonding wire inductor between the on-chip integrated antenna and the VCO output, the measured emission power at distance of 5 m from RF transmitter was -37 dBm (0.2 μW).

  6. The Booster to AGS beam transfer fast kicker systems

    SciTech Connect

    Zhang, W.; Bunicci, J.; Soukas, A.V.; Zhang, S.Y.

    1992-01-01

    The Brookhaven AGS Booster has a very successful commissioning period in June 1991. The third phase of that commissioning was a beam extraction test. The Booster extraction fast kicker (F3) deflected a 1.2 GeV proton beam from the Booster circulating orbit into the extraction septum aperture, partially down the extraction line to a temporary beam stop. Now, the Booster is committed to the AGS operations program for both heavy ion and proton beams. Thus, the Booster extraction and the corresponding AGS injection systems must operate routinely up to a pulse repetition frequency of 7.5 Hertz, and up to a beam energy of 1.5 Gev. The injection fast kicker is located in the A5 section of the AGS ring and is used to deflect the proton or heavy ion beam into its final AGS closed orbit. A distinctive feature of the AGS injection fast kicker modulators is the tail-bitting function required for proton beam injection. This enables the system to produce a fast current fall time to go along with the high current pulse amplitude with a fast rise time. The AGS injection fast kicker system has three pulse modulators, and each modulator consists of two thyratrons. The main PFN thyratrons switch on the current, and the tail bitting thyratrons are used to force the magnet current to decrease rapidly. Two digital pulse delay generators are used to align the main thyratrons and the tail bitting thyratrons respectively. The system has been tested and installed. The final commissioning of the Booster to AGS beam transfer line and injection is currently being undertaken. In this article, the system design, realization techniques and performance data will be presented.

  7. The Booster to AGS beam transfer fast kicker systems

    SciTech Connect

    Zhang, W.; Bunicci, J.; Soukas, A.V.; Zhang, S.Y.

    1992-08-01

    The Brookhaven AGS Booster has a very successful commissioning period in June 1991. The third phase of that commissioning was a beam extraction test. The Booster extraction fast kicker (F3) deflected a 1.2 GeV proton beam from the Booster circulating orbit into the extraction septum aperture, partially down the extraction line to a temporary beam stop. Now, the Booster is committed to the AGS operations program for both heavy ion and proton beams. Thus, the Booster extraction and the corresponding AGS injection systems must operate routinely up to a pulse repetition frequency of 7.5 Hertz, and up to a beam energy of 1.5 Gev. The injection fast kicker is located in the A5 section of the AGS ring and is used to deflect the proton or heavy ion beam into its final AGS closed orbit. A distinctive feature of the AGS injection fast kicker modulators is the tail-bitting function required for proton beam injection. This enables the system to produce a fast current fall time to go along with the high current pulse amplitude with a fast rise time. The AGS injection fast kicker system has three pulse modulators, and each modulator consists of two thyratrons. The main PFN thyratrons switch on the current, and the tail bitting thyratrons are used to force the magnet current to decrease rapidly. Two digital pulse delay generators are used to align the main thyratrons and the tail bitting thyratrons respectively. The system has been tested and installed. The final commissioning of the Booster to AGS beam transfer line and injection is currently being undertaken. In this article, the system design, realization techniques and performance data will be presented.

  8. Development of an automatic frequency measurement system for RF linear accelerator magnetrons

    NASA Astrophysics Data System (ADS)

    Cha, Sungsu; Kim, Yujong; Lee, Byeong-No; Joo, Youngwoo; Lee, Soo Min; Lee, Byung Cheol; Cha, Hyungki; Lee, Seung Hyun; Park, Hyung Dal; Song, Ki Beak

    2015-06-01

    An X-band [9300 MHz] magnetron frequency measurement system was developed for the electron linear accelerators at the Korean Atomic Energy Research Institute (KAERI). The measurement and the display of the RF frequency during the accelerator operation time is a crucial factor for continuous operation for two key reasons. Firstly, if the RF frequency of the magnetron is not known, then the amount of frequency tuning cannot be known, and the appropriate RF power cannot be supplied to the accelerating-structure. Second, values including the accelerating-structure's coolingwater temperature setting, the solenoid-magnet's cooling-water temperature setting, and the tuning of the source's (magnetron's) frequency can be undertaken because the RF frequency is used as the reference. A key component of the accelerator is the accelerating-structure. The volume of the accelerating-structure changes according to the environment's temperature; there, the resonance frequency of the accelerating-structure varies. When the resonance frequency of the accelerator is changed, the output becomes unstable, and a low beam energy is obtained. Accordingly, was developed a magnetron frequency-measuring device in order to stabilize the accelerator's operation. The results of the test demonstrate that the measurement's accurate up to 100 kHz, which enables the provision of an accurate RF power to the accelerating -structure. In this paper, we discuss the RF frequency measurement system for the magnetron to enable a more stable accelerator operation in a linac.

  9. Outburst Activity of the Symbiotic System AG Dra

    NASA Astrophysics Data System (ADS)

    Gális, R.; Hric, L.; Leedjärv, L.; Kundra, E.

    2015-07-01

    AG Dra is one of the best studied symbiotic systems. A period analysis of new and historical photometric data, as well as radial velocities, confirmed the presence of the two periods — about 550 days, caused by orbital motion, and around 350 days, related to pulsations of the cool component of AG Dra. In addition, the active stages change distinctively, but the outbursts recur with periods from 359 to 375 days.

  10. System integration of RF based negative ion experimental facility at IPR

    NASA Astrophysics Data System (ADS)

    Bansal, G.; Bandyopadhyay, M.; Singh, M. J.; Gahlaut, A.; Soni, J.; Pandya, K.; Parmar, K. G.; Sonara, J.; Chakraborty, A.

    2010-02-01

    The setting up of RF based negative ion experimental facility shall witness the beginning of experiments on the negative ion source fusion applications in India. A 1 MHz RF generator shall launch 100 kW RF power into a single driver on the plasma source to produce a plasma of density ~5 × 1012 cm-3. The source can deliver a negative ion beam of ~10 A with a current density of ~30 mA/cm2 and accelerated to 35 kV through an electrostatic ion accelerator. The experimental system is similar to a RF based negative ion source, BATMAN, presently operating at IPP. The subsystems for source operation are designed and procured principally from indigenous resources, keeping the IPP configuration as a base line. The operation of negative ion source is supported by many subsystems e.g. vacuum pumping system with gate valves, cooling water system, gas feed system, cesium delivery system, RF generator, high voltage power supplies, data acquisition and control system, and different diagnostics. The first experiments of negative ion source are expected to start at IPR from the middle of 2009.

  11. Compact Superconducting Radio-frequency Accelerators and Innovative RF Systems

    SciTech Connect

    Kephart, Robert; Chattopadhyay, Swaapan; Milton, Stephen

    2015-04-10

    We will present several new technical and design breakthroughs that enable the creation of a new class of compact linear electron accelerators for industrial purposes. Use of Superconducting Radio-Frequency (SRF) cavities allow accelerators less than 1.5 M in length to create electron beams beyond 10 MeV and with average beam powers measured in 10’s of KW. These machines can have the capability to vary the output energy dynamically to produce brehmstrahlung x-rays of varying spectral coverage for applications such as rapid scanning of moving cargo for security purposes. Such compact accelerators will also be cost effective for many existing and new industrial applications. Examples include radiation crosslinking of plastics and rubbers, creation of pure materials with surface properties radically altered from the bulk, modification of bulk or surface optical properties of materials, sterilization of medical instruments animal solid or liquid waste, and destruction of organic compounds in industrial waste water effluents. Small enough to be located on a mobile platform, such accelerators will enable new remediation methods for chemical and biological spills and/or in-situ crosslinking of materials. We will describe one current design under development at Fermilab including plans for prototype and value-engineering to reduce costs. We will also describe development of new nano-structured field-emitter arrays as sources of electrons, new methods for fabricating and cooling superconducting RF cavities, and a new novel RF power source based on magnetrons with full phase and amplitude control.

  12. Plasma properties of RF magnetron sputtering system using Zn target

    SciTech Connect

    Nafarizal, N.; Andreas Albert, A. R.; Sharifah Amirah, A. S.; Salwa, O.; Riyaz Ahmad, M. A.

    2012-06-29

    In the present work, we investigate the fundamental properties of magnetron sputtering plasma using Zn target and its deposited Zn thin film. The magnetron sputtering plasma was produced using radio frequency (RF) power supply and Argon (Ar) as ambient gas. A Langmuir probe was used to collect the current from the plasma and from the current intensity, we calculate the electron density and electron temperature. The properties of Zn sputtering plasma at various discharge conditions were studied. At the RF power ranging from 20 to 100 W and gas pressure 5 mTorr, we found that the electron temperature was almost unchanged between 2-2.5 eV. On the other hand, the electron temperature increased drastically from 6 Multiplication-Sign 10{sup 9} to 1 Multiplication-Sign 10{sup 10}cm{sup -3} when the discharge gas pressure increased from 5 to 10 mTorr. The electron microscope images show that the grain size of Zn thin film increase when the discharge power is increased. This may be due to the enhancement of plasma density and sputtered Zn density.

  13. System studies of rf current drive for MST

    NASA Astrophysics Data System (ADS)

    Anderson, J. K.; Burke, D. R.; Diem, S.; Forest, C. B.; Goetz, J. A.; Harvey, R. W.; Hendries, E. R.; Kaufman, M. C.; Seltzman, A. H.; Thomas, M. A.

    2011-12-01

    Two rf schemes are being studied on the MST reversed field pinch for their potential in current profile control experiments. MHD modeling has shown that a substantial externally-driven off axis parallel current can improve stability of the dominant core tearing modes. A radially localized axisymmetric population of fast electrons has been observed by SXR emission during LH injection ( 100kW at 800MHz), and is consistent with CQL3D modeling which predicts a small driven current. Computational work suggests that doubling the input power will statistically improve the LH-induced SXR signal to background ratio, and that about 2MW of injected power (an order of magnitude increase) will drive enough current for stabilization of tearing modes. Additionally, a 1 MW 5.5 GHz electron Bernstein wave (EBW) experiment is under construction, which utilizes a very simple and compact antenna compatible with the demands of the RFP. EBW allows access to electron cyclotron heating and current drive in the overdense plasma. Coupling of the external electromagnetic wave to the EBW has been demonstrated, and initial tests at ˜100kW power have produced a small, localized xray flux consistent with rf heating and high diffusivity of fast electrons. Computational work is currently underway to answer the very important questions of how much power is required, and what level of electron diffusivity is tolerable, to generate a consequential amount of EBW current.

  14. Superionic behavior in the xAgI-(1-x)CsAg2I3 polycrystalline system

    NASA Astrophysics Data System (ADS)

    Rodríguez, L. A.; Zapata, J.; Vargas, R. A.; Peña Lara, D.; Diosa, J. E.

    2016-06-01

    A superionic phase behavior (with DC ionic conductivities higher than 0.01 S/cm) has been observed in xAgI-(1-x)CsAg2I3 (x≈0.67) polycrystalline system grown by slow evaporation using AgI and CsI powders (molar ratio Cs/Ag=0.25) as starting salts and an aqueous solution of HI as solvent. The transition from the normal-to- the superionic state is first-order with a hysteretic behavior in temperature centered at about 116 °C as reflected by thermal (DSC) and electrical conductivity measurements. This mixture is composed of CsAg2I3 and AgI crystalline phases and an additional amorphous AgI phase that explains the glassy-type behavior observed in the superionic phase transition.

  15. An Overview of the MaRIE X-FEL and Electron Radiography LINAC RF Systems

    SciTech Connect

    Bradley, Joseph Thomas III; Rees, Daniel Earl; Scheinker, Alexander; Sheffield, Richard L.

    2015-05-04

    The purpose of the Matter-Radiation Interactions in Extremes (MaRIE) facility at Los Alamos National Laboratory is to investigate the performance limits of materials in extreme environments. The MaRIE facility will utilize a 12 GeV linac to drive an X-ray Free-Electron Laser (FEL). Most of the same linac will also be used to perform electron radiography. The main linac is driven by two shorter linacs; one short linac optimized for X-FEL pulses and one for electron radiography. The RF systems have historically been the one of the largest single component costs of a linac. We will describe the details of the different types of RF systems required by each part of the linacs. Starting with the High Power RF system, we will present our methodology for the choice of RF system peak power and pulselength with respect to klystron parameters, modulator parameters, performance requirements and relative costs. We will also present an overview of the Low Level RF systems that are proposed for MaRIE and briefly describe their use with some proposed control schemes.

  16. Shuttle STS-2 mission communication systems RF coverage and performance predictions. Volume 1: Ascent

    NASA Technical Reports Server (NTRS)

    Porter, J. A.; Gibson, J. S.; Kroll, Q. D.; Loh, Y. C.

    1981-01-01

    The RF communications capabilities and nominally expected performance for the ascent phase of the second orbital flight of the shuttle are provided. Predicted performance is given mainly in the form of plots of signal strength versus elapsed mission time for the STDN (downlink) and shuttle orbiter (uplink) receivers for the S-band PM and FM, and UHF systems. Performance of the NAV and landing RF systems is treated for RTLS abort, since in this case the spacecraft will loop around and return to the launch site. NAV and landing RF systems include TACAN, MSBLS, and C-band altimeter. Signal strength plots were produced by a computer program which combines the spacecraft trajectory, antenna patterns, transmit and receive performance characteristics, and system mathematical models. When available, measured spacecraft parameters were used in the predictions; otherwise, specified values were used. Specified ground station parameter values were also used. Thresholds and other criteria on the graphs are explained.

  17. Update on RF System Studies and VCX Fast Tuner Work for the RIA Drive Linac

    SciTech Connect

    Rusnak, B; Shen, S

    2003-05-06

    The limited cavity beam loading conditions anticipated for the Rare Isotope Accelerator (RIA) create a situation where microphonic-induced cavity detuning dominates radio frequency (RF) coupling and RF system architecture choices in the linac design process. Where most superconducting electron and proton linacs have beam-loaded bandwidths that are comparable to or greater than typical microphonic detuning bandwidths on the cavities, the beam-loaded bandwidths for many heavy-ion species in the RIA driver linac can be as much as a factor of 10 less than the projected 80-150 Hz microphonic control window for the RF structures along the driver, making RF control problematic. While simply overcoupling the coupler to the cavity can mitigate this problem to some degree, system studies indicate that for the low-{beta} driver linac alone, this approach may cost 50% or more than an RF system employing a voltage controlled reactance (VCX) fast tuner. An update of these system cost studies, along with the status of the VCX work being done at Lawrence Livermore National Lab is presented here.

  18. Spacecraft-level verification of the Van Allen Probes' RF communication system

    NASA Astrophysics Data System (ADS)

    Crowne, M. J.; Srinivasan, D.; Royster, D.; Weaver, G.; Matlin, D.; Mosavi, N.

    This paper presents the verification process, lessons learned, and selected test results of the radio frequency (RF) communication system of the Van Allen Probes, formerly known as the Radiation Belt Storm Probes (RBSP). The Van Allen Probes mission is investigating the doughnut-shaped regions of space known as the Van Allen radiation belts where the Sun interacts with charged particles trapped in Earth's magnetic field. Understanding this dynamic area that surrounds our planet is important to improving our ability to design spacecraft and missions for reliability and astronaut safety. The Van Allen Probes mission features two nearly identical spacecraft designed, built, and operated by the Johns Hopkins University Applied Physics Laboratory (JHU/APL) for the National Aeronautics and Space Administration (NASA). The RF communication system features the JHU/APL Frontier Radio. The Frontier Radio is a software-defined radio (SDR) designed for spaceborne communications, navigation, radio science, and sensor applications. This mission marks the first spaceflight usage of the Frontier Radio. RF ground support equipment (RF GSE) was developed using a ground station receiver similar to what will be used in flight and whose capabilities provided clarity into RF system performance that was previously not obtained until compatibility testing with the ground segments. The Van Allen Probes underwent EMC, acoustic, vibration, and thermal vacuum testing at the environmental test facilities at APL. During this time the RF communication system was rigorously tested to ensure optimal performance, including system-level testing down to threshold power levels. Compatibility tests were performed with the JHU/APL Satellite Communication Facility (SCF), the Universal Space Network (USN), and the Tracking and Data Relay Satellite System (TDRSS). Successful completion of this program as described in this paper validated the design of the system and demonstrated that it will be able to me

  19. Generalization of susceptibility of RF systems through far-field pattern superposition

    NASA Astrophysics Data System (ADS)

    Verdin, B.; Debroux, P.

    2015-05-01

    The purpose of this paper is to perform an analysis of RF (Radio Frequency) communication systems in a large electromagnetic environment to identify its susceptibility to jamming systems. We propose a new method that incorporates the use of reciprocity and superposition of the far-field radiation pattern of the RF system and the far-field radiation pattern of the jammer system. By using this method we can find the susceptibility pattern of RF systems with respect to the elevation and azimuth angles. A scenario was modeled with HFSS (High Frequency Structural Simulator) where the radiation pattern of the jammer was simulated as a cylindrical horn antenna. The RF jamming entry point used was a half-wave dipole inside a cavity with apertures that approximates a land-mobile vehicle, the dipole approximates a leaky coax cable. Because of the limitation of the simulation method, electrically large electromagnetic environments cannot be quickly simulated using HFSS's finite element method (FEM). Therefore, the combination of the transmit antenna radiation pattern (horn) superimposed onto the receive antenna pattern (dipole) was performed in MATLAB. A 2D or 3D susceptibility pattern is obtained with respect to the azimuth and elevation angles. In addition, by incorporating the jamming equation into this algorithm, the received jamming power as a function of distance at the RF receiver Pr(Φr, θr) can be calculated. The received power depends on antenna properties, propagation factor and system losses. Test cases include: a cavity with four apertures, a cavity above an infinite ground plane, and a land-mobile vehicle approximation. By using the proposed algorithm a susceptibility analysis of RF systems in electromagnetic environments can be performed.

  20. Aspects of operation of the Fermilab Booster RF System at very high intensity

    SciTech Connect

    Griffin, J.E.

    1996-04-01

    The purpose of this note is to examine the likelihood and problems associated with operation of the Fermilab Booster rf systems as it presently exists, or with only minor modifications, at beam intensity approaching 5x10{sup 13} protons per pulse. Beam loading of the rf system at such an intensity will be one order of magnitude larger than at the present operation level. It is assumed that the injection energy will be raised to 1 GeV with no major increase in the injected energy spread (longitudinal emittance). The beam will be bunched by adiabatic capture as is presently done although it may be necessary to remove one or two bunches prior to acceleration to allow clean extraction at 8 GeV. At very high intensity the charge in each bunch will interact with the vacuum chamber impedance (and with itself) in such a way as to reduce in some cases the bucket area generated by the rf voltage. Because this decrement must be made up by changes in the rf ring voltage if the required bucket area is to be maintained, these effects must be taken into consideration in any analysis of the capability of the rf system to accelerate very large intensity.

  1. Development of system level integration of compact RF components on multilayer liquid crystal polymer (LCP)

    NASA Astrophysics Data System (ADS)

    Chung, David

    The objective of this research is to optimize compactness for reconfigurable wireless communication systems by integrating Radio Frequency (RF) components on a multilayer Liquid Crystal Polymer (LCP) package while minimizing the size and interconnection of each component. To achieve this goal, various RF/microwave components have been integrated on LCP with the design, fabrication, and testing results to explore the feasibility of the designs for RF applications. The first chapter of this research focuses on the characterization of via interconnects for 3D system designs. As a crucial component for achieving compact multilayer designs, various transition designs are explored from DC to 110 GHz. In particular, High Density Interconnects (HDI) are investigated to achieve low loss performance at mm-wave frequencies. An example of accessing the input and output of a LCP packaged device using via interconnects is included. In addition, a heat sink using via technology is presented for active cooling of heat generating embedded devices. Chapters 3, 4, and 5 demonstrate the results of RF Micro-Electro-Mechanical Systems (MEMS) switches integrated on LCP to create compact reconfigurable devices. RF MEMS switches are essential for designing compact multi-functional devices. A pattern reconfigurable antenna with monolithically integrated RF MEMS switches is presented. In addition, a compact 3D phase shifter using RF MEMS switches for a 2 x 2 phased antenna array is also presented in this work. To create a phased antenna array that is more compatible with Integrated Circuits (IC), Lead Zirconate Titanate (PZT) RF MEMS switches are used to make a low voltage phase shifter. The actuation voltage is under 10 V, which is more easily achievable in a integrated system compared to commonly used electrostatic actuated RF MEMS switches that required at least 30 V. In Chapter 6, an expandable, low cost, and conformal multilayer phased antenna array is presented. Starting with a 4 x 8

  2. Simulation and analysis of rf feedback systems on the SLC damping rings

    SciTech Connect

    Minty, M.; Himel, T.; Krejcik, P.; Siemann, R.H.; Tighe, R.

    1993-09-01

    The rf system of the SLC Damping Rings has evolved since tighter tolerances on beam stability are encountered as beam intensities are increased. There are now many feedback systems controlling the phase and amplitude of the rf, the phase of the beam, and the tune of the cavity. The bandwidths of the feedback loops range from several MHz to compensate for beam loading to a few Hz for the cavity tuners. To improve our understanding of the interaction of these loops and verify the expected behavior, we have simulated their behavior using computer models. A description of the models and the first results are discussed.

  3. Analysis Of Phase Transitions In Quasi-Two-Dimensional Dusty Systems In RF-Discharge Plasma

    SciTech Connect

    Adamovich, X. G.; Vaulina, O. S.; Khrustalev, Yu. V.; Nekhaevsky, Yu. Yu.; Petrov, O. F.; Fortov, V. E.

    2008-09-07

    In this work, we investigate the phase transitions in quasi-two-dimensional systems of dusty plasma in RF discharge. The quasi-2D systems are considered, where the areas with different phase states (dusty liquid and dusty crystal) coexist. The parameters of these areas of dusty subsystem are estimated, the obtained results are analysed and compared with theoretical predictions.

  4. Capture, acceleration and bunching rf systems for the MEIC booster and storage rings

    SciTech Connect

    Wang, Shaoheng; Guo, Jiquan; Lin, Fanglei; Morozov, Vasiliy; Rimmer, Robert A.; Wang, Haipeng; Zhang, Yuhong

    2015-09-01

    The Medium-energy Electron Ion Collider (MEIC), proposed by Jefferson Lab, consists of a series of accelerators. The electron collider ring accepts electrons from CEBAF at energies from 3 to 12 GeV. Protons and ions are delivered to a booster and captured in a long bunch before being ramped and transferred to the ion collider ring. The ion collider ring accelerates a small number of long ion bunches to colliding energy before they are re-bunched into a high frequency train of very short bunches for colliding. Two sets of low frequency RF systems are needed for the long ion bunch energy ramping in the booster and ion collider ring. Another two sets of high frequency RF cavities are needed for re-bunching in the ion collider ring and compensating synchrotron radiation energy loss in the electron collider ring. The requirements from energy ramping, ion beam bunching, electron beam energy compensation, collective effects, beam loading and feedback capability, RF power capability, etc. are presented. The preliminary designs of these RF systems are presented. Concepts for the baseline cavity and RF station configurations are described, as well as some options that may allow more flexible injection and acceleration schemes.

  5. Investigation of the Stability of the RF Gun of the SSRL Injector System

    SciTech Connect

    Moore, J

    2004-02-05

    In the previous three years, Stanford Synchrotron Radiation Laboratory (SSRL) has experienced electron beam instabilities in the injector system of the Stanford Positron Electron Asymmetric Ring (SPEAR). Currently, for approximately the past four months the radio frequency (RF) gun of the linear accelerator injector system of the SPEAR at SSRL has become increasingly unstable. The current of the RF gun has become progressively sluggish and the lifetime of the cathode within the RF gun has been much shorter than expected. The cathode also sustains many unexplained damages. The instability of the RF gun affects the entire operation of SPEAR, creating substantial inconvenience. Through mechanical, design, and procedural analysis of the RF gun and the cathode that emits the electron beam of the linear accelerator, a solution to prolong the life of the cathode and secure the stability of the gun can be found. The thorough analysis of the gun and cathode involves investigation into the history of cathode installation and removal through the years of SPEAR operation as well as interviews with SSRL personnel involved with the upkeep of the gun and cathode. From speaking with SSRL employees and reviewing several articles many possible causes for beam instability were presented. The most likely cause of the SSRL gun instability is excessive back bombardment that can be attributed to running the cathode at too high a temperature.

  6. Recycler barrier RF buckets

    SciTech Connect

    Bhat, C.M.; /Fermilab

    2011-03-01

    The Recycler Ring at Fermilab uses a barrier rf systems for all of its rf manipulations. In this paper, I will give an overview of historical perspective on barrier rf system, the longitudinal beam dynamics issues, aspects of rf linearization to produce long flat bunches and methods used for emittance measurements of the beam in the RR barrier rf buckets. Current rf manipulation schemes used for antiproton beam stacking and longitudinal momentum mining of the RR beam for the Tevatron collider operation are explained along with their importance in spectacular success of the Tevatron luminosity performance.

  7. RF-SQUID to DC-SQUID upgrade of a 28-channel magnetoencephalography (MEG) system

    NASA Astrophysics Data System (ADS)

    Diekmann, V.; Jürgens, R.; Becker, W.; Elias, H.; Ludwig, W.; Vodel, W.

    1996-05-01

    A Dornier 28-channel magnetoencephalography (MEG) system equipped with RF-SQUIDs and control electronics made by CTF (Port Coquitlam, BC, Canada) was upgraded by replacing the RF-SQUIDs with DC-SQUIDs developed at the University of Jena, Germany. New preamplifiers were designed that emulate the function of the system's original RF amplifiers. This allowed the continuing use of the system's control electronics without any modification. Retaining these control devices was instrumental for preserving the system's unique ability to derive software-defined gradiometer measurements from its magnetometer signals, and also saved a considerable investment of control software tailored to the characteristics of these devices. The performance of the upgraded system compares favourably to that of other multichannel instruments; its software gradiometer channels typically attain an overall sensitivity of 0957-0233/7/5/017/img7 (an improvement by a factor of three over the original RF system) and suppress residual noise inside the shielded room by 40 to 60 dB. Also described are the procedures used to calibrate the system, to eliminate crosstalk between neighbouring channels, and to determine the coefficients for optimum suppression of ambient noise by the software gradiometer.

  8. A Multi-moded Delay Line RF Distribution System for the Next = Linear Collider

    NASA Astrophysics Data System (ADS)

    Tantawi, Sami

    1998-04-01

    The Delay Line Distribution System (DLDS) (H. Mizuno, Y. Otake, "A New Rf Power Distribution System For X Band Linac Equivalent To An Rf Pulse Compression Scheme Of Factor 2**N," 17th International Linac Conference (LINAC94), Tsukuba, Japan, Aug 21 - 26, 1994) is an alternative to conventional pulse compression which enhances the peak power of an rf source while matching the long pulse of that source to the shorter filling time of the accelerator structure. We present a variation on that scheme that combines the parallel delay lines of the system into one single line. The power of several sources is combined into a single waveguide delay line using a multi-mode launcher. The output mode of the launcher is determined by the phase coding of the input signals. The combined power is extracted using several mode extractors each extracts only one single mode. Hence, the phase coding of the sources controls the output port of the combined power. The power is, then, fed to the local accelerator structures. We present a detailed design of such a system, including several implementation methods for the launchers, extractors, and ancillary high power rf components. The system is designed so that it can handle the 600 MW peak power required for the high-gradient linacs of the Next Linear Collider, while maintaining high efficiency.

  9. RF BEAM CONTROL SYSTEM FOR THE BROOKHAVEN RELATIVISTIC HEAVY ION COLLIDER, RHIC

    SciTech Connect

    BRENNAN,J.M.; CAMPBELL,A.; DELONG,J.; HAYES,T.; ONILLON,E.; ROSE,J.; VETTER,K.

    1998-06-22

    The Relativistic Heavy Ion Collider, RHIC, is two counter-rotating rings with six interaction points. The RF Beam Control system for each ring will control two 28 MHz cavities for acceleration, and five 197 MHz cavities for preserving the 5 ns bunch length during 10 hour beam stores. Digital technology is used extensively in: Direct Digital Synthesis of rf signals and Digital Signal Processing for, the realization of state-variable feedback loops, real-time calculation of rf frequency, and bunch-by-bunch phase measurement of the 120 bunches. DSP technology enables programming the parameters of the feedback loops in order to obtain closed-loop dynamics that are independent of synchrotron frequency.

  10. Intelligent low-level RF system by non-destructive beam monitoring device for cyclotrons

    NASA Astrophysics Data System (ADS)

    Sharifi Asadi Malafeh, M. S.; Ghergherehchi, M.; Afarideh, H.; Chai, J. S.; Yoon, Sang Kim

    2016-04-01

    The project of a 10 MeV PET cyclotron accelerator for medical diagnosis and treatment was started at Amirkabir University of Technology in 2012. The low-level RF system of the cyclotron accelerator is designed to stabilize acceleration voltage and control the resonance frequency of the cavity. In this work an Intelligent Low Level Radio Frequency Circuit or ILLRF, suitable for most AVF cyclotron accelerators, is designed using a beam monitoring device and narrow band tunable band-pass filter. In this design, the RF phase detection does not need signal processing by a microcontroller.

  11. Concurrent System Engineering and Risk Reduction for Dual-Band (RF/optical) Spacecraft Communications

    NASA Technical Reports Server (NTRS)

    Fielhauer, Karl, B.; Boone, Bradley, G.; Raible, Daniel, E.

    2012-01-01

    This paper describes a system engineering approach to examining the potential for combining elements of a deep-space RF and optical communications payload, for the purpose of reducing the size, weight and power burden on the spacecraft and the mission. Figures of merit and analytical methodologies are discussed to conduct trade studies, and several potential technology integration strategies are presented. Finally, the NASA Integrated Radio and Optical Communications (iROC) project is described, which directly addresses the combined RF and optical approach.

  12. New high power 200 MHz RF system for the LANSCE drift tube linac

    SciTech Connect

    Lyles, J.; Friedrichs, C.; Lynch, M.

    1998-12-31

    The Los Alamos Neutron Science Center (LANSCE) linac provides an 800 MeV direct H{sup +} proton beam, and injects H{sup {minus}} to the upgraded proton storage ring for charge accumulation for the Short Pulse Spallation Source. Accelerating these interlaced beams requires high average power from the 201.25 MHz drift tube linac (DTL) RF system. Three power amplifiers have operated at up to three Megawatts with 12% duty factor. The total number of electron power tubes in the RF amplifiers and their modulators has been reduced from fifty-two to twenty-four. The plant continues to utilize the original design of a tetrode driving a super power triode. Further increases in the linac duty factor are limited, in part, by the maximum dissipation ratings of the triodes. A description of the system modifications proposed to overcome these limitations includes new power amplifiers using low-level RF modulation for tank field control. The first high power Diacrode{reg_sign} is being delivered and a new amplifier cavity is being designed. With only eight power tubes, the new system will deliver both peak power and high duty factor, with lower mains power and cooling requirements. The remaining components needed for the new RF system will be discussed.

  13. Compact rf heating and levitation systems for the NASA modular electromagnetic levitator

    NASA Technical Reports Server (NTRS)

    Fox, R. J.

    1990-01-01

    The levitator demonstrates levitation of a 5 mm diam aluminum sphere at 1 G using a small, compact rf levitator operating from a small 12-V battery. This system is designed to levitate and melt niobium in space; however, the small battery unit limits the power for melting operations.

  14. New low-level rf system for the Fermilab Booster synchrotron

    SciTech Connect

    Kerns, C.; Crisp, J.; Kerns, Q.; Miller, H.

    1987-03-01

    This paper describes the Booster low-level rf system that was constructed to meet these recently added requirements: (1) synthesizer controlled capture frequency at injection, (2) very low-phase noise over the machine cycle, (3) smooth phase-lock of beam to an external reference frequency and (4) ability to accelerate either a full turn or partial turn of beam.

  15. Plasma injection and capture at electron cyclotron resonance in a mirror system with additional rf fields

    SciTech Connect

    Golovanivskii, K.S.; Dugar-Zhabon, V.D.; Karyaka, V.I.; Milant'ev, V.P.; Turikov, V.A.

    1980-03-01

    Experiments and numerical simulations have been carried out to determine how cyclotron-resonance rf fields in an open magnetic mirror system affect the capture and confinement of a plasma injected along the axis. The results show that at electron cyclotron resonance the fields greatly improve the longitudinal plasma confinement.

  16. A new slip stacking RF system for a twofold power upgrade of Fermilab's Accelerator Complex

    SciTech Connect

    Madrak, Robyn

    2014-09-11

    Fermilab@?s Accelerator Complex has been recently upgraded, in order to increase the 120GeV proton beam power on target from about 400kW to over 700kW for NO@nA and other future intensity frontier experiments. One of the key ingredients of the upgrade is the offloading of some Main Injector synchrotron operations - beam injection and RF manipulation called ''slip stacking'' - to the 8GeV Recycler Ring, which had until recently been used only for low-intensity antiproton storage and cooling. This required construction of two new 53MHz RF systems for the slip-stacking manipulations. The cavities operate simultaneously at V_p_e_a_k@?150kV, but at slightly different frequencies (@Df=1260Hz). Their installation was completed in September 2013. This paper describes the novel solutions used in the design of the new cavities, their tuning system, and the associated high power RF system. First results showing effective operation of the RF system, beam capture and successful slip-stacking in the Recycler Ring are presented.

  17. Adsorbate-Induced Segregation in a PdAg Membrane Model System: Pd3Ag(1 1 1)

    SciTech Connect

    Svenum, I. H.; Herron, Jeffrey A.; Mavrikakis, Manos; Venvik, H. J.

    2012-10-15

    Thin PdAg alloy membranes with 20–25% Ag are being developed for hydrogen separation technology. Despite many investigations on such membranes as well as representative experimental and theoretical model systems, unresolved issues remain concerning the effect of the alloy surface structure and composition on adsorption and vice versa. Therefore, the interaction between hydrogen, carbon monoxide or oxygen with the surface of a PdAg model alloy was studied using periodic self-consistent density functional theory (DFT-GGA) calculations. In particular, the adsorption structure, coverage dependence and possible adsorption-induced segregation phenomena were addressed using Pd3Ag(1 1 1) model surfaces with varying degrees of surface segregation. In agreement with previous experimental and theoretical investigations, we predict Ag surface termination to be energetically favorable in vacuum. The segregation of Ag is then reversed upon adsorption of H, CO or O. For these adsorbates, the binding is strongest on Pd three-fold hollow sites, and hence complete Pd termination is favored at high coverage of H or CO, while 25% Ag may remain under oxygen because of the lower O-saturation coverage. CO adsorption provides a somewhat stronger driving force for Pd segregation when compared to H, and this may have implications with respect to permeation properties of PdAg alloy surfaces. Our predictions for high coverage are particularly relevant in underlining the importance of segregation phenomena to the hydrogen transport properties of thin PdAg alloy membranes.

  18. High intensity proton operation at the Brookhaven AGS accelerator complex

    SciTech Connect

    Ahrens, L.A.; Blaskiewicz, M.; Bleser, E.; Brennan, J.M.; Gardner, C.; Glenn, J.W.; Onillon, E.; Reece, R.K.; Roser, T.; Soukas, A.

    1994-08-01

    With the completion of the AGS rf upgrade, and the implementation of a transition {open_quotes}jump{close_quotes}, all of accelerator systems were in place in 1994 to allow acceleration of the proton intensity available from the AGS Booster injector to AGS extraction energy and delivery to the high energy users. Beam commissioning results with these new systems are presented. Progress in identifying and overcoming other obstacles to higher intensity are given. These include a careful exploration of the stopband strengths present on the AGS injection magnetic porch, and implementation of the AGS single bunch transverse dampers throughout the acceleration cycle.

  19. Space Station communications and tracking systems modeling and RF link simulation

    NASA Astrophysics Data System (ADS)

    Tsang, Chit-Sang; Chie, Chak M.; Lindsey, William C.

    1986-07-01

    In this final report, the effort spent on Space Station Communications and Tracking System Modeling and RF Link Simulation is described in detail. The effort is mainly divided into three parts: frequency division multiple access (FDMA) system simulation modeling and software implementation; a study on design and evaluation of a functional computerized RF link simulation/analysis system for Space Station; and a study on design and evaluation of simulation system architecture. This report documents the results of these studies. In addition, a separate User's Manual on Space Communications Simulation System (SCSS) (Version 1) documents the software developed for the Space Station FDMA communications system simulation. The final report, SCSS user's manual, and the software located in the NASA JSC system analysis division's VAX 750 computer together serve as the deliverables from LinCom for this project effort.

  20. Space Station communications and tracking systems modeling and RF link simulation

    NASA Technical Reports Server (NTRS)

    Tsang, Chit-Sang; Chie, Chak M.; Lindsey, William C.

    1986-01-01

    In this final report, the effort spent on Space Station Communications and Tracking System Modeling and RF Link Simulation is described in detail. The effort is mainly divided into three parts: frequency division multiple access (FDMA) system simulation modeling and software implementation; a study on design and evaluation of a functional computerized RF link simulation/analysis system for Space Station; and a study on design and evaluation of simulation system architecture. This report documents the results of these studies. In addition, a separate User's Manual on Space Communications Simulation System (SCSS) (Version 1) documents the software developed for the Space Station FDMA communications system simulation. The final report, SCSS user's manual, and the software located in the NASA JSC system analysis division's VAX 750 computer together serve as the deliverables from LinCom for this project effort.

  1. Timing and low-level rf system for an x-ray laser

    NASA Astrophysics Data System (ADS)

    Otake, Yuji; Maesaka, Hirokazu; Matsubara, Shinich; Hosoda, Naoyasu; Ohshima, Takashi

    2016-02-01

    An x-ray free-electron laser (XFEL), SACLA, designed to open up new science, was constructed for generating coherent x rays with a peak power of more than 10 GW and a very short pulse of below 30 fs. This feature demands a very highly short-term temporal stability of less than 50 fs to the acceleration rf field of SACLA. For this reason, we developed a timing and low-level rf (LLRF) system for SACLA based on that of the SPring8 compact SASE source (SCSS) test accelerator for verifying the feasibility of an XFEL. The performance of the system using the in-phase and quadrature rf manipulation method was improved from SCSS's system. Since the facility length of SACLA is 700 m, which is 10 times longer than that of the SCSS test accelerator, a phase-stabilized optical-fiber system designed to transmit time standard rf signals with low loss was also developed and deployed. This optical-fiber system equips fiber optical-length feedback control in order to mitigate environmental effects, such as temperature and humidity changes. On the other hand, the demanded maximum rf temporal stability is less than 50 fs, which is almost 10 times smaller than that of the SCSS test accelerator. Hence, reducing electric noise and increasing the temperature stability around timing and LLRF instruments were necessary and realized with a very low-noise power supply and a hemathermal 19-inch enclosure. The short-term temporal performance of the timing LLRF system finally attained a temporal stability of less than 13.6 fs in rms measured by a beam arrival-time measurement. This stability greatly helps to achieve the stable x-ray lasing of SACLA for routine operation during user experiments.

  2. Design and Implementation of RF Energy Harvesting System for Low-Power Electronic Devices

    NASA Astrophysics Data System (ADS)

    Uzun, Yunus

    2016-08-01

    Radio frequency (RF) energy harvester systems are a good alternative for energizing of low-power electronics devices. In this work, an RF energy harvester is presented to obtain energy from Global System for Mobile Communications (GSM) 900 MHz signals. The energy harvester, consisting of a two-stage Dickson voltage multiplier circuit and L-type impedance matching circuits, was designed, simulated, fabricated and tested experimentally in terms of its performance. Simulation and experimental works were carried out for various input power levels, load resistances and input frequencies. Both simulation and experimental works have been carried out for this frequency band. An efficiency of 45% is obtained from the system at 0 dBm input power level using the impedance matching circuit. This corresponds to the power of 450 μW and this value is sufficient for many low-power devices. The most important parameters affecting the efficiency of the RF energy harvester are the input power level, frequency band, impedance matching and voltage multiplier circuits, load resistance and the selection of diodes. RF energy harvester designs should be optimized in terms of these parameters.

  3. Chemically-inactive interfaces in thin film Ag/AgI systems for resistive switching memories

    PubMed Central

    Cho, Deok-Yong; Tappertzhofen, Stefan; Waser, Rainer; Valov, Ilia

    2013-01-01

    AgI nanoionics-based resistive switching memories were studied in respect to chemical stability of the Ag/AgI interface using x-ray absorption spectroscopy. The apparent dissolution of Ag films of thickness below some tens of nanometers and the loss of electrode/electrolyte contact was critically addressed. The results evidently show that there are no chemical interactions at the interface despite the high ionic mobility of Ag ions. Simulation results further show that Ag metal clusters can form in the AgI layer with intermediate-range order at least up to next-next nearest neighbors, suggesting that Ag can permeate into the AgI only in an aggregated form of metal crystallite. PMID:23378904

  4. RF system developments for CW and/or long pulse linacs

    SciTech Connect

    Lynch, M.

    1998-12-31

    High Power Proton Linacs are under development or proposed for development at Los Alamos and elsewhere. By current standards these linacs all require very large amounts of RF power. The Accelerator for Production of Tritium (APT) is a CW accelerator with an output current and energy of 100 mA and 1,700 MeV, respectively. The Spallation Neutron Source (SNS), in its ultimate configuration, is a pulsed accelerator with an average output power of 4 MW of beam. Other accelerators such as those that address transmutation and upgrades to LANSCE have similar requirements. For these high average power applications, the RF systems represent approximately half of the total cost of the linac and are thus key elements in the design and configuration of the accelerator. Los Alamos is fortunate to be actively working on both APT and SNS. For these programs the author is pursuing a number of component developments which are aimed at one or more of the key issues for large RF systems: technical performance, capital cost, reliability, and operating efficiency. This paper briefly describes some of the linac applications and then provides updates on the key RF developments being pursued.

  5. In Depth Diagnostics for RF System Operation in the PEP-II B Factory

    SciTech Connect

    Van Winkle, Daniel; Fox, John; Teytelman, Dmitry; /SLAC

    2005-05-27

    The PEP-II RF systems incorporate numerous feedback loops in the low-level processing for impedance control and operating point regulation. The interaction of the multiple loops with the beam is complicated, and the systems incorporate online diagnostic tools to configure the feedback loops as well as to record fault files in the case of an RF abort. Rapid and consistent analysis of the RF-related beam aborts and other failures is critical to the reliable operation of the B-Factory, especially at the recently achieved high beam currents. Procedures and algorithms used to extract diagnostic information from time domain fault files are presented and illustrated via example interpretations of PEP-II fault file data. Example faults presented will highlight the subtle interpretation required to determine the root cause. Some such examples are: abort kicker firing asynchronously, klystron and cavity arcs, beam loss leading to longitudinal instability, tuner read back jumps and poorly configured low-level RF feedback loop.

  6. A prototype RF power source system for the X-band linear collider

    SciTech Connect

    Mizuno, H.

    1995-07-05

    Since 1988, R&D of the X-band klystron in KEK has been carried out, and in this R&D program the two types of the X-band klystrons has been designed and tested (REF-1,2,3). The first one is the 30MW class klystron named XB-50k. This rather moderate peak power klystron was designed as the first step to the 100MW class klystron, and in 1992, could achieve 26MW peak power successfully. This XB-50k{number_sign}1a had supplied the RF power to the first X-band accelerating structure high power test in autumn of 1992. The second klystron named XB-72k in this R&D program, was designed as the first 100MW class klystron which could fulfill the minimum power requirement for the RF power source of the X-band linac in the next generation of several hundreds GeV electron positron linear colliders. The first XB-72k{number_sign}1 was tested in 1992 and 1993, and successfully achieved the peak spring and also achieved 95MW. In order to verify the technological feasibility of the conventional klystron power system as the possible candidate of the future X-band linear collider, the prototype RF power system including the RF pulse compression scheme and the modulator is discussed. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  7. A prototype RF power source system for the X-band linear collider

    NASA Astrophysics Data System (ADS)

    Mizuno, H.

    1995-07-01

    Since 1988, R&D of the X-band klystron in KEK has been carried out, and in this R&D program the two types of the X-band klystrons has been designed and tested (REF-1,2,3). The first one is the 30MW class klystron named XB-50k. This rather moderate peak power klystron was designed as the first step to the 100MW class klystron, and in 1992, could achieve 26MW peak power successfully. This XB-50k♯1a had supplied the RF power to the first X-band accelerating structure high power test in autumn of 1992. The second klystron named XB-72k in this R&D program, was designed as the first 100MW class klystron which could fulfill the minimum power requirement for the RF power source of the X-band linac in the next generation of several hundreds GeV electron positron linear colliders. The first XB-72k♯1 was tested in 1992 and 1993, and successfully achieved the peak spring and also achieved 95MW. In order to verify the technological feasibility of the conventional klystron power system as the possible candidate of the future X-band linear collider, the prototype RF power system including the RF pulse compression scheme and the modulator is discussed.

  8. Integration of LHCD system with SST1 machine and its high power rf performance in vacuum

    NASA Astrophysics Data System (ADS)

    Sharma, P. K.; Ambulkar, K. K.; Dalakoti, S.; Parmar, P. R.; Virani, C. G.; Thakur, A. L.

    2014-02-01

    A 2.0 MW CW lower hybrid current drive (LHCD) system based on 3.7 GHz klystron sources, is in advanced stage of commissioning, which would drive and sustain plasma current, non-inductively, in superconducting steadystate tokamak (SST1) for long pulse operation. Four klystrons, each rated for 0.5 MW CW rf power, delivers 2.0 MW of rf power to four layer of the LHCD system, which finally feeds the rf power to grill antenna. The antenna system along with vacuum window and vacuum transmission line is successfully integrated on the machine. Its vacuum and pressurization compatibility has been successfully established. To validate the high power performance of LHCD system for SST1 machine, stage-wise commissioning of LHCD system in staggered manner is planned. It has been envisaged that LHCD power may be gradually increased initially, since full power may not be required during the initial phases of SST1 plasma operation. Also if the system is integrated in steps or in phases, then integration issues, as well as high power operational issues, if any, can be addressed, attended and handled in a simpler way before integrating all the layers to the grill antenna. To begin with, one klystron is connected to one layer, out of four layers, which energizes a quarter of the grill antenna. Gradually, the rf power and its pulse length is increased to validate high power performance of the system. Arcing and reflections are observed as rf power is gradually increased. The problems are analysed and after taking appropriate remedial action the system performance is improved for operation up to 160kW. Several trains of short pulses are launched in SST1 vacuum vessel for rf conditioning of the LHCD system. Normally, reflections are high when power is launched in vacuum; therefore the pulse length is restricted up to 100 milliseconds. The high power performance of this layer, connected with grill antenna is validated by launching high power microwaves in vacuum vessel of SST1 machine

  9. A low-level rf control system for a quarter-wave resonator

    NASA Astrophysics Data System (ADS)

    Kim, Jongwon; Hwang, Churlkew

    2012-06-01

    A low-level rf control system was designed and built for an rf deflector, which is a quarter wave resonator, and was designed to deflect a secondary electron beam to measure the bunch length of an ion beam. The deflector has a resonance frequency near 88 MHz, its required phase stability is approximately ±1° and its amplitude stability is less than ±1%. The control system consists of analog input and output components and a digital system based on a field-programmable gate array for signal processing. The system is cost effective, while meeting the stability requirements. Some basic properties of the control system were measured. Then, the capability of the rf control was tested using a mechanical vibrator made of a dielectric rod attached to an audio speaker system, which could induce regulated perturbations in the electric fields of the resonator. The control system was flexible so that its parameters could be easily configured to compensate for the disturbance induced in the resonator.

  10. Instrumentation and control of the AGS Booster vacuum system

    SciTech Connect

    Gabusi, J.; Geller, J.; Hseuh, H.C.; Rosas, P.; Sandburg, J.; Shen, B.; Stattel, P.; Zapasek, R.

    1991-01-01

    The AGS Booster is a synchrotron for the acceleration of both protons and heavy ions. A pressure of low 10{sup {minus}11} Torr is required for the acceleration of the partially stripped, low {Beta}, very heavy ions. This paper describes the power supplies and controls for this ultra-high vacuum system with the emphasis on the operation of the ion gauge system over long cable length and on equipment interlock 4 refs., 2 figs., 1 tab.

  11. RF Distribution System for High Power Test of the SNS Cryomodule

    SciTech Connect

    Lee, Sung-Woo; Kang, Yoon W; Broyles, Michael R; Crofford, Mark T; Geng, Xiaosong; Kim, Sang-Ho; Phibbs, Curtis L; Strong, William Herb; Peglow, Robert C; Vassioutchenko, Alexandre V

    2012-01-01

    A four-way waveguide RF power distribution system for testing the Spallation Neutron Source (SNS) multi-cavity cryomodule to investigate the collective behavior has been developed. A single klystron operating at 805MHz for 1.3 msec at 60Hz powers the 4-way waveguide splitter to deliver up to 400 kW to individual cavities. Each cavity is fed through a combination of waveguide splitters and vector modulators (VM) to provide independent magnitude and phase controls. The waveguide vector modulator consists of two quadrature hybrids and two motorized waveguide phase shifters. The phase shifters and the assembled waveguide vector modulators were individually tested and characterized for low power and high RF power in the SNS RF test facility. Precise calibrations of magnitude and phase were performed to generate the look up tables (LUTs) to provide operational references during the cryomodule test. An I-Q demodulator module was developed and utilized to measure relative phases in pulsed high RF power operation. PLC units were developed for mechanical control of the phase shifters. Initial low/high power measurements were made using LabVIEW. An operation algorithm has been implemented into EPICS control for the cryomodule test stand.

  12. Improved Controls for Fusion RF Systems. Final technical report

    SciTech Connect

    Casey, Jeffrey A.

    2011-11-08

    We have addressed the specific requirements for the integrated systems controlling an array of klystrons used for Lower Hybrid Current Drive (LHCD). The immediate goal for our design was to modernize the transmitter protection system (TPS) for LHCD on the Alcator C-Mod tokamak at the MIT Plasma Science and Fusion Center (MIT-PSFC). Working with the Alcator C-Mod team, we have upgraded the design of these controls to retrofit for improvements in performance and safety, as well as to facilitate the upcoming expansion from 12 to 16 klystrons. The longer range goals to generalize the designs in such a way that they will be of benefit to other programs within the international fusion effort was met by designing a system which was flexible enough to address all the MIT system requirements, and modular enough to adapt to a large variety of other requirements with minimal reconfiguration.

  13. Battery-Powered RF Pre-Ionization System for the Caltech Magnetohydrodynamically-Driven Jet Experiment: RF Discharge Properties and MHD-Driven Jet Dynamics

    NASA Astrophysics Data System (ADS)

    Chaplin, Vernon H.

    This thesis describes investigations of two classes of laboratory plasmas with rather different properties: partially ionized low pressure radiofrequency (RF) discharges, and fully ionized high density magnetohydrodynamically (MHD)-driven jets. An RF pre-ionization system was developed to enable neutral gas breakdown at lower pressures and create hotter, faster jets in the Caltech MHD-Driven Jet Experiment. The RF plasma source used a custom pulsed 3 kW 13.56 MHz RF power amplifier that was powered by AA batteries, allowing it to safely float at 4-6 kV with the cathode of the jet experiment. The argon RF discharge equilibrium and transport properties were analyzed, and novel jet dynamics were observed. Although the RF plasma source was conceived as a wave-heated helicon source, scaling measurements and numerical modeling showed that inductive coupling was the dominant energy input mechanism. A one-dimensional time-dependent fluid model was developed to quantitatively explain the expansion of the pre-ionized plasma into the jet experiment chamber. The plasma transitioned from an ionizing phase with depressed neutral emission to a recombining phase with enhanced emission during the course of the experiment, causing fast camera images to be a poor indicator of the density distribution. Under certain conditions, the total visible and infrared brightness and the downstream ion density both increased after the RF power was turned off. The time-dependent emission patterns were used for an indirect measurement of the neutral gas pressure. The low-mass jets formed with the aid of the pre-ionization system were extremely narrow and collimated near the electrodes, with peak density exceeding that of jets created without pre-ionization. The initial neutral gas distribution prior to plasma breakdown was found to be critical in determining the ultimate jet structure. The visible radius of the dense central jet column was several times narrower than the axial current channel

  14. Glass formation and high conductivity in the ternary system AgI + Ag/sub 3/AsO/sub 4/ + AgPO/sub 3/: host to glassy AgI

    SciTech Connect

    Martin, S.W.; Schiraldi, A.

    1985-05-09

    Wide regions of glass formation have been found in the ternary system xAgI + yAg/sub 3/AsO/sub 4/ + (1 - x - y)AgPO/sub 3/. Glasses containing up to 75 mol % AgI can be formed in sections greater than 2 cm thick without signs of devitrification. Glass transition temperatures as high as 175/sup 0/C for glasses containing approx. 10 mol% AgI fall to approx. 45/sup 0/C at the highest AgI content. An equivalent ratio of AgI:N is defined and it is found that, for all glass-forming compositions, the electrical data as expressed in the Arrhenius form, sigma = A exp(-E/sub act/RT), log (sigma/omega cm)/sup -1/), log (A/omega cm)/sup -1/), E/sub act//(kcal mol/sup -1/), and additionally T/sub g/K, can be described as linear functions of N. These data are used to give support to the view of these glasses as being hosts to a liquidlike AgI giving rise to the high conductivity they exhibit, as high as 0.0143 (omega cm)/sup -1/ at room temperature for glasses containing the maximum AgI. Finally, from these linear relationships, functions for the mobility ..mu.. and number of the mobile Ag/sup +/ cations n are developed. 29 references, 8 figures, 2 tables.

  15. RF System Modelling for the JLab 12 GeV Upgrade and RIA

    SciTech Connect

    Alicia Hofler; Jean Delayen; J. Hovater; Stefan Simrock

    2003-10-01

    Jefferson Lab is using the MATLAB/Simulink library for RF systems developed for TTF as a tool to develop a model of its 12 GeV upgrade and the Rare Isotope Accelerator (RIA) to study the behavior and performance of the RF control system. The library includes elements describing a superconducting cavity with mechanical modes excited by Lorentz Force effects and a klystron including saturation characteristics. It can be applied to gradient and phase or in-phase and quadrature control for cavities operating in either a self-excited loop or generator driven mode. We will provide an overview of the theory behind the library components and present initial modeling results for Jefferson Lab's 12 GeV Upgrade and the RIA systems.

  16. Design of a new VHF RF power amplifier system for LANSCE

    SciTech Connect

    Lyles, John T M

    2010-01-01

    A major upgrade is replacing much of the 40 year-old proton drift tube linac RF system with new components at the Los Alamos Neutron Science Center (LANSCE). When installed, the new system will reduce the total number of electron power tubes from twenty-four to eight in the RF powerplant. A new 200 MHz high power cavity amplifier has being developed at LANSCE. This 3.2 MW final power amplifier (FPA) uses a Thales TH628 Diacrode{reg_sign}, a state-of-the-art tetrode that eliminates the large anode modulator of the triode-based FPA that has been in use for four decades. Drive power for the FPA is provided by a new tetrode intermediate power amplifier (and a solid-state driver stage). The new system has sufficient duty-factor capability to allow LANSCE to return to 1 MW beam operation. Prototype RF power amplifiers have been designed, fabricated, and assembled, and are being tested. High voltage DC power became available through innovative re-engineering of an installed system. Details of the electrical and mechanical design of the FPA and ancillary systems are discussed.

  17. Design of an RF System for Electron Bernstein Wave Studies in MST

    NASA Astrophysics Data System (ADS)

    Kauffold, J. X.; Seltzman, A. H.; Anderson, J. K.; Nonn, P. D.; Forest, C. B.

    2010-11-01

    Motivated by the possibility of current profile control a 5.5GHz RF system for EBW is being developed. The central component is a standard radar Klystron with 1.2MW peak power and 4μs typical pulse length. Meaningful experiments require RF pulse lengths similar to the characteristic electron confinement times in MST necessitating the creation of a power supply providing 80kV at 40A for 10ms. A low inductance IGBT network switches power at 20kHz from an electrolytic capacitor bank into the primary of a three-phase resonant transformer system that is then rectified and filtered. The system uses three magnetically separate transformers with microcrystalline iron cores to provide suitable volt-seconds and low hysteresis losses. Each phase has a secondary with a large leakage inductance and a parallel capacitor providing a boost ratio greater than 60:1 with a physical turns ratio of 13.5:1. A microprocessor feedback control system varies the drive frequency around resonance to regulate the boost ratio and provide a stable output as the storage bank discharges. The completed system will deliver RF to the plasma boundary where coupling to the Bernstein mode and subsequent heating and current drive can occur.

  18. Switch over to the high frequency rf systems near transition

    SciTech Connect

    Brennan, J.M.; Wei, J.

    1988-01-01

    The purpose of this note is to point out that since bunch narrowing naturally occurs in the acceleration process in the vicinity of transition, it should be possible to switch over to the high frequency system close to transition when the bunch has narrowed enough to fit directly into the high frequency bucket. The advantage of this approach is the simplicity, no extra components or gymnastics are required of the low frequency system. The disadvantage, of course, is for protons which do not go through transition. But on the other hand, there is no shortage of intensity for protons and so it should be possible to keep the phase space area low for protons, and then matching to the high frequency bucket should be easily accomplished by adiabatic compression. 3 refs., 7 figs.

  19. Bandwidth utilization maximization of scientific RF communication systems

    SciTech Connect

    Rey, D.; Ryan, W.; Ross, M.

    1997-01-01

    A method for more efficiently utilizing the frequency bandwidth allocated for data transmission is presented. Current space and range communication systems use modulation and coding schemes that transmit 0.5 to 1.0 bits per second per Hertz of radio frequency bandwidth. The goal in this LDRD project is to increase the bandwidth utilization by employing advanced digital communications techniques. This is done with little or no increase in the transmit power which is usually very limited on airborne systems. Teaming with New Mexico State University, an implementation of trellis coded modulation (TCM), a coding and modulation scheme pioneered by Ungerboeck, was developed for this application and simulated on a computer. TCM provides a means for reliably transmitting data while simultaneously increasing bandwidth efficiency. The penalty is increased receiver complexity. In particular, the trellis decoder requires high-speed, application-specific digital signal processing (DSP) chips. A system solution based on the QualComm Viterbi decoder and the Graychip DSP receiver chips is presented.

  20. Performance of the RF bunch coalescing system in the Fermilab main ring

    SciTech Connect

    Martin, P.; Meisner, K.; Miller, H.; Nicholls, G.; Wildman, D.

    1985-10-01

    Both the proton and antiproton bunches which will collide in the Tevatron have longitudinal emittance greater than can be accelerated by the Main Ring from 8 GeV without large loss and emittance growth. To circumvent this restriction, several bunches of smaller intensity are accelerated in the Main Ring to an energy of 150 GeV where these bunches are coalesced into a single high-intensity bunch. Coalescing has possible uses in other applications. Applications could be any time that a beam which has been accelerated by an rf system of one frequency must be captured by another rf frequency. The bunch coalescing system is described and some preliminary coalescing results are shown.

  1. The linac and booster RF systems for a dedicated injector for SPEAR

    SciTech Connect

    Weaver, J.N.; Baird, S., Baltay, M.; Borland, M.; Nuhn, H.D.; Safranek, J.; Chavis, C.; Emery, L.; Genin, R.D.; Hettel, R.; Morales, H.; Sebek, J.; Voss, J.; Wang, H.; Wiedemann, H.; Youngmann, B. . Stanford Synchrotron Radiation Lab.); Miller, R.H. )

    1991-05-01

    A 120 MeV, 2856 MHz, TW linac, with a microwave gun, alpha magnet, and chopper, has been built at SSRL as a preinjector for and along with a 3 GeV booster synchrotron ring. The resulting injector will be available on demand to fill SPEAR, which is a storage ring now dedicated to synchrotron light production. The linac sections were purchased from China, the XK-5 klystrons were obtained surplus from SLAC, the modulators are a variation on those at SLAC and were built by SSRL, the alpha magnet and chopper were designed and built at SSRL and the microwave gun was designed and built in collaboration with Varian Associates. The rf system for the booster ring is similar to those at SPEAR and PEP and was built by SSRL. Some of the interesting mechanical and electrical details are discussed and the operating characteristics of the linac and ring rf system are highlighted. 8 refs., 6 figs.

  2. High power RF solid state power amplifier system

    NASA Technical Reports Server (NTRS)

    Sims, III, William Herbert (Inventor); Chavers, Donald Gregory (Inventor); Richeson, James J. (Inventor)

    2011-01-01

    A high power, high frequency, solid state power amplifier system includes a plurality of input multiple port splitters for receiving a high-frequency input and for dividing the input into a plurality of outputs and a plurality of solid state amplifier units. Each amplifier unit includes a plurality of amplifiers, and each amplifier is individually connected to one of the outputs of multiport splitters and produces a corresponding amplified output. A plurality of multiport combiners combine the amplified outputs of the amplifiers of each of the amplifier units to a combined output. Automatic level control protection circuitry protects the amplifiers and maintains a substantial constant amplifier power output.

  3. The role of reduction extent of graphene oxide in the photocatalytic performance of Ag/AgX (X = Cl, Br)/rGO composites and the pseudo-second-order kinetics reaction nature of the Ag/AgBr system.

    PubMed

    Gao, Weiyin; Ran, Chenxin; Wang, Minqiang; Li, Le; Sun, Zhongwang; Yao, Xi

    2016-07-21

    Although reduced graphene oxide (rGO)-based photocatalyst composites have been intensively developed during the past few years, the influence of reduction extent of rGO on the photocatalytic performance of the rGO-based composite has virtually not been investigated due to some technical limitations, such as the poor water dispersibility of rGO and low reduction selectivity of the hydrothermal method, which make it difficult to control the reduction extent of rGO in these composites. Herein, we used a facile room-temperature method to synthesize Ag/AgX (X = Cl, Br)/rGO photocatalyst composites as a model to study the effect of reduction extent of rGO on the photocatalytic performance of the photocatalyst. It was found that the photocatalytic activities of both Ag/AgCl/PrGO and Ag/AgBr/PrGO systems had an optimized threshold of the reduction extent of photoreduced GO (PrGO). More importantly, due to the different conductive band values of AgCl and AgBr, the optimized thresholds in the two systems were at different PrGO reduction extents, based on which we proposed that the favorable energy band matching between AgX and PrGO in the two systems played a crucial role in obtaining high photocatalysis performance. Besides, the photocatalytic reaction of the Ag/AgBr based system was confirmed to be a pseudo-second-order kinetics reaction rather than pseudo-first-order kinetics reaction. The new insights presented in this work provided useful information on the design and development of a more sophisticated photocatalyst, and can also be applied to many other applications. PMID:27332751

  4. 50 MW X-BAND RF SYSTEM FOR A PHOTOINJECTOR TEST STATION AT LLNL

    SciTech Connect

    Marsh, R A; Anderson, S G; Barty, C J; Beer, G K; Cross, R R; Ebbers, C A; Gibson, D J; Hartemann, F V; Houck, T L; Adolphsen, C; Candel, A; Chu, T S; Jongewaard, E N; Li, Z; Raubenheimer, T; Tantawi, S G; Vlieks, A; Wang, F; Wang, J W; Zhou, F; Deis, G A

    2011-03-11

    In support of X-band photoinjector development efforts at LLNL, a 50 MW test station is being constructed to investigate structure and photocathode optimization for future upgrades. A SLAC XL-4 klystron capable of generating 50 MW, 1.5 microsecond pulses will be the high power RF source for the system. Timing of the laser pulse on the photocathode with the applied RF field places very stringent requirements on phase jitter and drift. To achieve these requirements, the klystron will be powered by a state of the art, solid-state, high voltage modulator. The 50 MW will be divided between the photoinjector and a traveling wave accelerator section. A high power phase shifter is located between the photoinjector and accelerator section to adjust the phasing of the electron bunches with respect to the accelerating field. A variable attenuator is included on the input of the photoinjector. The distribution system including the various x-band components is being designed and constructed. In this paper, we will present the design, layout, and status of the RF system.

  5. Integrated design and analysis of RF heating and current drive systems

    NASA Astrophysics Data System (ADS)

    Ryan, P. M.; Carter, M. D.; Goulding, R. H.; Batchelor, D. B.; Jaeger, E. F.; Stallings, D. C.; Wang, C. Y.; Baity, F. W.; Bell, G. L.; Bigelow, T. S.; England, A. C.; Hanson, G. R.; Haste, G. R.; Hoffman, D. J.; Murakami, M.; Rasmussen, D. A.; Wilgen, J. B.; Rogers, J. H.; Majeski, R.; Schilling, G.; Wilson, J. R.; Bhatnagar, V.; Bures, M.; Kaye, A.; Start, D.; Wade, T.; Ho, Y. L.; Kruger, W.

    1996-02-01

    The design, analysis, and performance evaluation of rf power systems ultimately requires accurate modeling of a chain of subsystems starting with the rf transmitter and ending with the power absorption in the plasma. A collection of computer codes is used at ORNL to calculate the plasma loading and wave spectrum for a three-dimensional rf antenna, the transmission/reflection properties of the Faraday shield and its effect on the electrical characteristics and phase velocity of the antenna, the internal coupling among antenna array components and the incorporation of the antenna array into a transmission line model of the phase control, tuning, matching, and power distribution system. Some codes and techniques are more suited for the rapid evaluation of system design progressions, while others are more applicable to the detailed analysis of final designs or existing hardware. The interaction of codes and the accuracy of calculations will be illustrated by the process of determining the plasma loading as a function of phasing and density profiles for the TFTR ICRH antennas and comparing the results to measurements. An example of modeling a complex antenna geometry will be the comparison of calculations with the measured electrical response of a four-strap mockup of the JET A2 antenna array which was loaned to ORNL by the JET ICRH team.

  6. Beam Pipe HOM Absorber for 750 MHz RF Cavity Systems

    SciTech Connect

    Johnson, Rolland; Neubauer, Michael

    2014-10-29

    This joint project of Muons, Inc., Cornell University and SLAC was supported by a Phase I and Phase II grant monitored by the SBIR Office of Science of the DOE. Beam line HOM absorbers are a critical part of future linear colliders. The use of lossy materials at cryogenic temperatures has been incorporated in several systems. The design in beam pipes requires cylinders of lossy material mechanically confined in such a way as to absorb the microwave energy from the higher-order modes and remove the heat generated in the lossy material. Furthermore, the potential for charge build-up on the surface of the lossy material requires the conductivity of the material to remain consistent from room temperature to cryogenic temperatures. In this program a mechanical design was developed that solved several design constraints: a) fitting into the existing Cornell load vacuum component, b) allowing the use of different material compositions, c) a thermal design that relied upon the compression of the lossy ceramic material without adding stress. Coating experiments were performed that indicated the design constraints needed to fully implement this approach for solving the charge build-up problem inherent in using lossy ceramics. In addition, the ACE3P program, used to calculate the performance of lossy cylinders in beam pipes in general, was supported by this project. Code development and documentation to allow for the more wide spread use of the program was a direct result of this project was well.

  7. The system AgI-AgBr: Energetic consequences of defect equilibria in single-phase and two-phase regions

    SciTech Connect

    Khandkar, A.; Navrotsky, A.; Tare, V.B.; Wagner, J.B.

    1984-11-01

    The enthalpy of solution of various single- and two-phase AgI-AgBr compositions in AgNO/sub 3/ at 518 K has been determined using a Calvet-type twin microcalorimeter. The enthalpy (H/sub 518/ - H/sub 298/) of melted and unmelted mixtures of AgI and AgBr of various compositions within two-phase regions of the phase diagram has also been obtained using the same calorimeter. The effect of AgBr on the temperature and enthalpy of transformation of ..beta..-AgI to ..cap alpha..AgI has been investigated using a Perkin Elmer Differential Scanning Calorimeter. The terminal compositions at 518 K of the two-phase region of AgI-AgBr system has been found to be AgI /SUB 0.85/ Br /SUB 0.15/ and AgI /SUB 0.3/ Br /SUB 0.7/ . The excess enthalpy, the difference in (H/sub 518/ - H/sub 298/) values of the unmelted and melted mixtures in the two-phase region of the AgI-AgBr system, has been found to be maximum at the equivolume concentration of the two terminal phases and is suggested to be due to the generation of silver ion vacancies at the interfaces due to a space-charge layer.

  8. Development of deflector cavity and RF amplifier for bunch length detector system

    NASA Astrophysics Data System (ADS)

    Pandey, H. K.; Bhattacharya, T. K.; Chakrabarti, A.

    2016-02-01

    A minimally-interceptive bunch length detector system is being developed for measurement of longitudinal dimension of the bunch beam from RFQ of the radioactive ion beam (RIB) facility at VECC. This detector system is based on secondary electrons emission produced by the primary ion beam hitting a thin tungsten wire placed in the beam path. In this paper we report the design, development and off line testing results of deflector cavity together with its RF sysytem. The deflector cavity is a capacitive loaded helical type λ/2 resonator driven by RF source of 500 W at 37.8 MHz solid state amplifier, realized by combining two amplifier modules of 300 W each. The measured RF characteristics of the resonator, such as frequency, Q value and shunt impedance have been found to be reasonably good and close to the analytical estimation and results of simulation. The design philosophy and test results of individual components of the amplifier are discussed. The test result upto full power shows a good harmonic separation at the individual module level and this is found to improve further when modules are combined together.The results of high power performance test of the deflector cavity together with amplifier are also reported.

  9. RF and data acquisition systems for Fermilab's ILC SRF cavity vertical test stand

    SciTech Connect

    Ozelis, Joseph P.; Nehring, Roger; Grenoble, Christiana; Powers, Thomas J.; /Jefferson Lab

    2007-06-01

    Fermilab is developing a facility for vertical testing of SRF cavities as part of its ILC program. The RF system for this facility is based on the proven production cavity test systems used at Jefferson Lab for CEBAF and SNS cavity testing. The design approach is modular in nature, using commercial-off-the-shelf (COTS) components. This yields a system that can be easily debugged and modified, and with ready availability of spares. Comprehensive data acquisition and control is provided by a PXI-based hardware platform in conjunction with software developed in the LabView programming environment.

  10. Cognitive Cellular Systems: A New Challenge on the RF Analog Frontend

    NASA Astrophysics Data System (ADS)

    Varga, Gabor; Schrey, Moritz; Subbiah, Iyappan; Ashok, Arun; Heinen, Stefan

    2016-07-01

    Cognitive Cellular Systems are seen today as one of the most promising ways of moving forward solving or at least easing the still worsening situation of congested spectrum caused by the growing number of users and the expectation of higher data transfer rates. As the intelligence of a Cognitive Radio system is located in the digital domain - the Cognitive Engine and associated layers - extensive research has been ongoing in that domain since Mitola published his idea in 1999. Since, a big progress has been made in the domain of architectures and algorithms making systems more efficient and highly flexible. The pace of this progress, however, is going to be impeded by hard requirements on the received and transmitted signal quality, introducing ultimate challenges on the performance of the RF analog frontend, such as in-band local oscillator harmonics, ultra low sensitivity and ultra high linearity. The RF frontend is thus likely to become the limiting technical factor in the true realization of a Cognitive Cellular System. Based on short recapitulations of the most crucial issues in RF analog design for Cognitive Systems, this article will point out why those mechanisms become responsible for the limitation of the overall performance particularly in a broadband Cognitive Cellular System. Furthermore, as part of a possible solution to ease the situation, system design of a high intermediate frequency (IF) to UHF frequency converter for cognitive radios is discussed and the performance of such a converter analyzed as a proof of concept. In addition to successfully tackling some of the challenges, such a high-IF converter enables white space operation for existing commercial devices by acting as frequency converter. From detailed measurements, the capabilities in both physical layer and application layer performance of a high-IF frontend developed out of off-the-shelf components is explained and is shown to provide negligible degradation to the commercial device

  11. Energy-efficient operation of a booster RF system for Taiwan light source operated in top-up mode

    NASA Astrophysics Data System (ADS)

    Yeh, Meng-Shu; Wang, Chaoen; Chang, Lung-Hai; Chung, Fu-Tsai; Yu, Tsung-Chi; Lin, Ming-Chyuan; Chen, Ling-Jhen; Yang, Tz-Te; Chang, Mei-Hsia; Lin, Yu-Han; Tsai, Ming-Hsun; Lo, Chih-Hung; Liu, Zong-Kai

    2015-03-01

    Contemporary light sources operate in a top-up mode to maintain their photon intensity quasi-constant so as to improve significantly the thermal stability of the photon beam and to maximize ultimately the average photon flux at a designed maximum operational beam current. Operating in a top-up mode requires frequent beam injection from the synchrotron booster to the storage ring of the light source, but the injection intervals occupy only a tiny portion of the operational time of the integrated machine. To maintain a high operational reliability, the booster RF system practically operates necessarily under injection conditions around the clock and consumes full electric power whether during top-up injection or not. How to decrease the power consumption of the booster RF system during its stand-by time but not to sacrifice the reliability and availability of the RF system is obviously of fundamental interest for routine operation of the light source in a top-up mode. Here, an energy-efficient operation of a booster RF system adaptive to top-up operation of a light source is proposed that has been developed, realized and integrated into the booster RF system of the Taiwan Light Source (TLS), and routinely operated since the end of year 2008. The klystron cathode current and RF gap voltage of the booster's accelerating RF cavity are both periodically modulated to adapt the injection rhythm during top-up operation, which results in decreased consumption of electric power of the booster RF system by more than 78%. The impact on the reliability and availability of the booster RF system has been carefully monitored during the past five operational years, delivering more than 5000 h scheduled user beam time per year. The booster RF system retains its excellent reliability and availability as previously. Neither a decrease of the service time nor an induced reliability issue from the klystron or any high-power high-voltage component of the transmitter has been experienced

  12. RF Micro-Electro-Mechanical Systems Capacitive Switches Using Ultra Thin Hafnium Oxide Dielectric

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Onodera, Kazumasa; Maeda, Ryutaro

    2006-01-01

    A π-type RF capacitive switch using about 45-nm-thick HfO2 dielectric layer was fabricated. High isolation performance was obtained in wide-band range when the switch was down-state. The isolation was better than -40 dB at the frequency range of 4-35 GHz. Particularly, the isolation was better than -50 dB in the frequency range of 8-12 GHz, i.e., X band. HfO2 showed excellent process compatibility with conventional microfabrication procedure. The 45-nm-thick HfO2 film was prepared using sputtering at room temperature so that it was feasible to be integrated into RF switch and other microwave circuits. The results of constant bias stressing showed that the ultra thin HfO2 had excellent reliability. The electric breakdown of HfO2 was observed, which had no apparent negative effects on the reliability of the dielectric. HfO2 dielectrics were attractive in the application of RF micro-electro-mechanical systems (MEMS) switch for new generation of low-loss high-linearity microwave circuits.

  13. Optimizing RF gun cavity geometry within an automated injector design system

    SciTech Connect

    Alicia Hofler ,Pavel Evtushenko

    2011-03-28

    RF guns play an integral role in the success of several light sources around the world, and properly designed and optimized cw superconducting RF (SRF) guns can provide a path to higher average brightness. As the need for these guns grows, it is important to have automated optimization software tools that vary the geometry of the gun cavity as part of the injector design process. This will allow designers to improve existing designs for present installations, extend the utility of these guns to other applications, and develop new designs. An evolutionary algorithm (EA) based system can provide this capability because EAs can search in parallel a large parameter space (often non-linear) and in a relatively short time identify promising regions of the space for more careful consideration. The injector designer can then evaluate more cavity design parameters during the injector optimization process against the beam performance requirements of the injector. This paper will describe an extension to the APISA software that allows the cavity geometry to be modified as part of the injector optimization and provide examples of its application to existing RF and SRF gun designs.

  14. Use of a first-harmonic RF system in the NSLS booster

    SciTech Connect

    Peterson, J.

    1984-08-01

    In order to capture and accelerate the maximum amount of beam injected into the booster from the linac and to put all of this beam into one bucket of the VUV or the X-Ray Ring, several scenarios involving a first-harmonic RF system can be considered: (a) accelerate with 5 full buckets (with the present 5th harmonic system) and coalesce the 5 bunches into one 1st harmonic bucket at flat-top, or possibly before flat top; (b) accelerate with a first harmonic (10.57 MHz) system all the way; or (c) accelerate with a first harmonic until the bunch has damped sufficiently to transfer to one of the fifth-harmonic buckets (suggested by Galayda to ease the voltage requirements on the first harmonic system). The capture efficiency at injection should be independent of the harmonic number of the RF system, unless there are deleterious beam-cavity interactions, in which case the first-harmonic system using ferrite could have an advantage because of its lossy characteristics at high frequencies. The acceleration efficiency should also be independent of harmonic number except at high beam intensities where collective instabilities can occur. In this domain the system with lower peak beam current would be favored. As will be seen, this consideration favors the fifth-harmonic acceleration system.

  15. The UHV system of the 10 MeV RF electron linac

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, D.; Jayaprakash, D.; Mishra, R. L.; Nimje, V. T.; Mittal, K. C.

    2008-05-01

    A 10 MeV, 10 kW RF Electron Linac, for Industrial applications, is installed and commissioned at Electron Beam Centre (EBC), Kharghar, Navi Mumbai. The accelerator consists of the electron gun, RF Linac, Vacuum system, Beam diagnostics system, Magnetic sweep scanning system and Scan horn. The accelerator is divided into three sections with gate valves to isolate them, to enable servicing of pumps and modifications. The vacuum requirement in the accelerator is 10-7 mbar considering the breakdown parameters of the RF field within the linac. Total length of the accelerator from electron gun to the scan horn is about 5.0 meters. Vacuum plumb lines are of SS 304 pipes of nominal bores of 100 mm and 150 mm, machined internally to a surface finish of 0.8 μm. It encloses a volume of 156 litres. Total surface area exposed to vacuum is 57,500 cm2. It consists of 5250 cm2 of OFHC Copper, 51300 cm2 of SS 304 and 940 cm2 of ceramic sections. Leak-tightness of the order of 1 × 10-9mbar.l/s is ensured for the whole system, after eliminating the leaks at every stage of the assembly. Baking the plumb line and pumps at 150° C, for eight hours an ultimate vacuum of 2 × 10-7mbar is achieved in the accelerator. Modifications of the vacuum system is undertaken to suit the design changes in the gun and the diagnostic systems.

  16. Investigation of RF Emissions From Wireless Networks as a Threat to Avionic Systems

    NASA Technical Reports Server (NTRS)

    Salud, Maria Theresa P.; Williams, Reuben A. (Technical Monitor)

    2002-01-01

    The paper focuses on understanding and obtaining preliminary measurements of radiated field (RF) emissions of laptop/wireless local area network (WLAN) systems. This work is part of a larger research project to measure radiated emissions of wireless devices to provide a better understanding for potential interference with crucial aircraft avionics systems. A reverberation chamber data collection process is included, as well as recommendations for additional tests. Analysis of measurements from devices under test (DUTs) proved inconclusive for addressing potential interference issues. Continued effort is expected to result in a complete easily reproducible test protocol. The data and protocol presented here are considered preliminary.

  17. AGS tune jump system to cross horizontal depolarization resonances overview

    SciTech Connect

    Glenn, J.W.; Ahrens, L.; Fu, W.; Mi, J.L.; Rosas, P.; Schoefer, V.; Theisen, C.; Altinbas, Z.

    2011-03-28

    Two partial snakes overcome the vertical depolarizing resonances in the AGS. But a new type of depolarizing intrinsic resonance from horizontal motion appeared. We reduce these using horizontal tune jumps timed to these resonances. We gain a factor of six in crossing rate with a tune jump of 0.05 in 100 {micro}s. Two quadrapoles, we described in 2009, pulse 42 times, the current matching beam energy. The power supplies for these quads are described in detail elsewhere in this conference. The controls for the Jump Quad system is based on a BNL designed Quad Function Generator. Two modules are used; one for timing, and one to supply reference voltages. Synchronization is provided by a proprietary serial bus, the Event Link. The AgsTuneJump application predicts the times of the resonances during the AGS cycle and calculates the power supply trigger times from externally collected tune and energy versus time data and the Low and High PS voltage functions from a voltage to current model of the power supply. The system was commissioned during runs 09 & 10 and is operational. Many beam effects are described elsewhere. The TuneJump system has worked well and has caused little trouble save for the perturbations in the lattice having such a large effect due to our need to run with the vertical tune within a few thousandths of the integer tune. As these problems were mostly sorted out by correcting the 6th harmonic orbit distortions which caused a large 18 theta beta wave. Also running with minimal chromaticity reduces emittance growth. There are still small beta waves which are being addressed. The timing of the pulses is still being investigated, but as each crossing causes minimal polarization loss, this is a lengthy process.

  18. Effect of insulating layer material on RF-induced heating for external fixation system in 1.5 T MRI system.

    PubMed

    Liu, Yan; Kainz, Wolfgang; Qian, Songsong; Wu, Wen; Chen, Ji

    2014-09-01

    The radio frequency (RF)-induced heating is a major concern when patients with medical devices are placed inside a magnetic resonance imaging (MRI) system. In this article, numerical studies are applied to investigate the potentials of using insulated materials to reduce the RF heating for external fixation devices. It is found that by changing the dielectric constant of the insulation material, the RF-induced heating at the tips of devices can be altered. This study indicates a potential technique of developing external fixation device with low MRI RF heating.

  19. Structural and Critical Behaviors of Ag Rough Films Deposited on Liquid Substrates

    NASA Astrophysics Data System (ADS)

    Ye, Gao-xiang; Feng, Chun-mu; Zhang, Qi-rui; Ge, Hong-liang; Zhang, Xuan-jia

    1996-10-01

    A new Ag rough film system, deposited on silicone oil surfaces by rf-magnetron sputtering method, has been fabricated. The chrysanthemum-like surface morphology at micron length scale is observed. It is proposed that the anomalous critical behavior mainly results from the relative shift between the Ag atom clusters and the substrate. The discussion of the deposition mechanism is also presented.

  20. A new technique for making bright proton bunches using barrier RF systems

    SciTech Connect

    Bhat, C.M.; /Fermilab

    2005-05-01

    I describe here a very promising scheme for producing bright proton bunches for proton-antiproton and proton-proton colliders. The method is based on the use of wide-band barrier rf systems. First, I explain the principle of the method. The beam dynamics simulations applied to the Fermilab Main Injector (MI) suggest that the scheme allows a wide range of bunch intensities and emittances for ppbar collider. This method has the potential to increase the instantaneous luminosity by {ge}30% at the Tevatron.

  1. Beam manipulation and compression using broadband rf systems in the Fermilab Main Injector and Recycler

    SciTech Connect

    G William Foster et al.

    2004-07-09

    A novel method for beam manipulation, compression, and stacking using a broad band RF system in circular accelerators is described. The method uses a series of linear voltage ramps in combination with moving barrier pulses to azimuthally compress, expand, or cog the beam. Beam manipulations can be accomplished rapidly and, in principle, without emittance growth. The general principle of the method is discussed using beam dynamics simulations. Beam experiments in the Fermilab Recycler Ring convincingly validate the concept. Preliminary experiments in the Fermilab Main Injector to investigate its potential for merging two ''booster batches'' to produce high intensity proton beams for neutrino and antiproton production are described.

  2. A COAXIAL TE011 CAVITY AND A SYSTEM TO MEASURE DC AND RF PROPERTIES OF SUPERCONDUCTORS

    SciTech Connect

    Gianluigi Ciovati; Peter Kneisel; Ganapati Myneni; Larry Turlington; Gary Slack; Michael Morrone; William Clemens; Richard Bundy; Thomas Elliott; Jayanta Mondal

    2008-01-23

    A coaxial niobium cavity has been designed and built where the center conductor consists of a removable sample. In addition, a system to measure properties such as magnetization, penetration depth, critical temperature and thermal conductivity on the same cylindrical sample has been designed and built. The purpose of this effort is to investigate possible correlations between DC and RF properties of superconductors. In this contribution, the design of the various components is discussed and the test results on a niobium sample obtained so far are presented.

  3. RF Control System for the SC cavity of the Tesla Test Facility Injector

    NASA Astrophysics Data System (ADS)

    Mosnier, A.; Chel, S.; Phung Ngoc, B.; Tessier, J. M.

    1997-05-01

    The superconducting cavity of the TTF injector, which operates in pulsed mode, must accelerate the non relativistic electron beam to an energy of 10 to 15 MeV. Lorentz forces and microphonics detunings are the major sources of cavity field fluctuation. In order to achieve amplitude and phase stabilities much smaller than 10-3 and 1 degree, an analog feedback system, mainly based on a self excited loop and I/Q modulators, has been developed. After a description of the RF control module, various measurements without and with beam are reported and compared with numerical simulations.

  4. RF and Data Acquisition Systems for Fermilab's ILC SRF Cavity Vertical Test Stand

    SciTech Connect

    Joseph P. Ozelis; Roger Nehring; Christiana Grenoble; Thomas J. Powers

    2007-06-01

    Fermilab is developing a facility for vertical testing of SRF cavities as part of a program to improve cavity performance reproducibility for the ILC. The RF system for this facility, using the classic combination of oscillator, phase detector/mixer, and loop amplifier to detect the resonant cavity frequency and lock onto the cavity, is based on the proven production cavity test systems used at Jefferson Lab for CEBAF and SNS cavity testing. The design approach is modular in nature, using commercial-off-the-shelf (COTS) components. This yields a system that can be easily debugged and modified, and with ready availability of spares. Data acquisition and control is provided by a PXI-based hardware platform in conjunction with software developed in the LabView programming environment. This software provides for amplitude and phase adjustment of incident RF power, and measures all relevant cavity power levels, cavity thermal environment parameters, as well as field emission-produced radiation. It also calculates the various cavity performance parameters and their associated errors. Performance during system commissioning and initial cavity tests will be presented.

  5. A Self-Powered Hybrid Energy Scavenging System Utilizing RF and Vibration Based Electromagnetic Harvesters

    NASA Astrophysics Data System (ADS)

    Uluşan, H.; Gharehbaghi, K.; Zorlu, Ö.; Muhtaroğlu, A.; Külah, H.

    2015-12-01

    This study presents a novel hybrid system that combines the power generated simultaneously by a vibration-based Electromagnetic (EM) harvester and a UHF band RF harvester. The novel hybrid scavenger interface uses a power management circuit in 180 nm CMOS technology to step-up and to regulate the combined output. At the first stage of the system, the RF harvester generates positive DC output with a 7-stage threshold compensated rectifier, while the EM harvester generates negative DC output with a self-powered AC/DC negative doubler circuit. At the second stage, the generated voltages are serially added, stepped-up with an on-chip charge pump circuit, and regulated to a typical battery voltage of 3 V. Test results indicate that the hybrid operation enables generation of 9 μW at 3 V output for a wide range of input stimulations, which could not be attained with either harvesting mode by itself. Moreover the hybrid system behaves as a typical battery, and keeps the output voltage stable at 3 V up to 18 μW of output power. The presented system is the first battery-like harvester to our knowledge that generates energy from two independent sources and regulates the output to a stable DC voltage.

  6. A multi-moded rf delay line distribution system for the next linear collider

    NASA Astrophysics Data System (ADS)

    Tantawi, S. G.; Bowden, G.; Farkas, Z. D.; Irwin, J.; Ko, K.; Kroll, N.; Lavine, T.; Li, Z.; Loewen, R.; Miller, R.; Nantista, C.; Ruth, R. D.; Rifkin, J.; Vlieks, A. E.; Wilson, P. B.; Adolphsen, C.; Wang, J.

    1999-07-01

    The Delay Line Distribution System (DLDS) (1) is an alternative to conventional pulse compression which enhances the peak power of an rf source while matching the long pulse of that source to the shorter filling time of the accelerator structure. We present a variation on that scheme that combines the parallel delay lines of the system into one single line. The power of several sources is combined into a single waveguide delay line using a multi-mode launcher. The output mode of the launcher is determined by the phase coding of the input signals. The combined power is extracted using several mode extractors, each of which extracts only one single mode. Hence, the phase coding of the sources controls the output port of the combined power. The power is then fed to the local accelerator structures. We present a detailed design of such a system, including several implementation methods for the launchers, extractors, and ancillary high power rf components. The system is designed so that it can handle the 600 MW peak power required by the NLC design, while maintaining high efficiency.

  7. Multi-Moded RF Delay Line Distribution System (MDLDS) for the Next Linear Collider

    NASA Astrophysics Data System (ADS)

    Nantista, C. D.

    2002-01-01

    The Delay Line Distribution System (DLDS) is an alternative to conventional pulse compression, which enhances the peak power of rf sources while matching the long pulse of those sources to the shorter filling time of accelerator structures. We present an implementation of this scheme that combines pairs of parallel delay lines of the system into single lines. The power of several sources is combined into a single waveguide delay line using a multi-mode launcher. The output mode of the launcher is determined by the phase coding of the input signals. The combined power is extracted from the delay line using mode-selective extractors, each of which extracts a single mode. Hence, the phase coding of the sources controls the output port of the combined power. The power is then fed to the local accelerator structures. We present a detailed design of such a system, including several implementation methods for the launchers, extractors, and ancillary high power rf components. The system is designed so that it can handle the 600 MW peak power required by the NLC design while maintaining high efficiency.

  8. Multimoded rf delay line distribution system for the Next Linear Collider

    NASA Astrophysics Data System (ADS)

    Tantawi, S. G.; Nantista, C.; Kroll, N.; Li, Z.; Miller, R.; Ruth, R.; Wilson, P.; Neilson, J.

    2002-03-01

    The delay line distribution system is an alternative to conventional pulse compression, which enhances the peak power of rf sources while matching the long pulse of those sources to the shorter filling time of accelerator structures. We present an implementation of this scheme that combines pairs of parallel delay lines of the system into single lines. The power of several sources is combined into a single waveguide delay line using a multimode launcher. The output mode of the launcher is determined by the phase coding of the input signals. The combined power is extracted from the delay line using mode-selective extractors, each of which extracts a single mode. Hence, the phase coding of the sources controls the output port of the combined power. The power is then fed to the local accelerator structures. We present a detailed design of such a system, including several implementation methods for the launchers, extractors, and ancillary high power rf components. The system is designed so that it can handle the 600 MW peak power required by the Next Linear Collider design while maintaining high efficiency.

  9. Design of RF Feed System for Standing-Wave Accelerator Structures

    SciTech Connect

    Neilson, Jeffrey; Tantawi, Sami; Dolgashev, Valery

    2010-11-04

    We are investigating a standing wave structure with an rf feed to each individual cell. This approach minimizes rf power flow and electromagnetic energy absorbed by an rf breakdown. The objective of this work is a robust high-gradient (above 100 MV/m) X-band accelerator structure.

  10. Design of RF Feed System for Standing-Wave Accelerator Structures

    SciTech Connect

    Neilson, J.; Tantawi, S.; Dolgashev, V.; /SLAC

    2012-05-25

    We are investigating a standing wave accelerator structure that uses a rf feed to each individual cell. This approach minimizes rf power flow and electromagnetic energy absorbed by an rf breakdown. The objective of this work is a robust high-gradient (above 100 MV/m) X-band accelerator structure.

  11. Hydrothermal single-crystal growth in the systems Ag/Hg/X/O (X = VV, AsV): crystal structures of (Ag3Hg)VO4, (Ag2Hg2)3(VO4)4, and (Ag2Hg2)2(HgO2)(AsO4)2 with the unusual tetrahedral cluster cations (Ag3Hg)3+ and (Ag2Hg2)4+ and crystal structure of AgHgVO4.

    PubMed

    Weil, Matthias; Tillmanns, Ekkehart; Pushcharovsky, Dmitry Yu

    2005-03-01

    Single crystals of (Ag3Hg)VO4 (I), (Ag2Hg2)3(VO4)4 (II), AgHgVO4 (III), and (Ag2Hg2)2(HgO2)(AsO4)2 (IV) were grown under hydrothermal conditions (250 degrees C, 5 d) from starting mixtures of elementary mercury, silver nitrate, ammonium vanadate, and disodium hydrogenarsenate, respectively. All crystal structures were determined from X-ray diffraction data, and their chemical compositions were confirmed by electron microprobe analysis. I crystallizes in the tillmannsite structure, whereas II-IV adopt new structure types: (I) I4, Z = 2, a = 7.7095(2) A, c = 4.6714(2) A, 730 structure factors, 24 parameters, R[F2 > 2sigma(F2)] = 0.0365; (II) I42d, Z = 4, a = 12.6295(13) A, c = 12.566(3) A, 1524 structure factors, 55 parameters, R[F2 > 2sigma(F2)] = 0.0508; (III) C2, Z = 4, a = 9.9407(18) A, b = 5.5730(8) A, c = 7.1210(19) A, beta = 94.561(10) degrees , 1129 structure factors, 48 parameters, R[F2 > 2sigma(F2)] = 0.0358; (IV) P31c, Z = 2, a = 6.0261(9) A, c = 21.577(4) A, 1362 structure factors, 52 parameters, R[F2 > 2sigma(F2)] = 0.0477. The most striking structural features of I, II, and IV are the formation of tetrahedral cluster cations (Ag3Hg)3+ and (Ag2Hg2)4+, respectively, built of statistically distributed Ag and Hg atoms with a metal-metal distance of about 2.72 A. The electronic structure of these clusters can formally be considered as two-electron-four-center bonding. The crystal structure of III differs from the protrusive structure types insofar as silver and mercury are located on distinct crystallographic sites without a notable metal-metal interaction >3.55 A. All crystal structures are completed by tetrahedral oxo anions XO4(3-) (X = VV, AsV) and for IV additionally by a mercurate group, HgO2(2-).

  12. Radio Frequency (RF) Micro-Electromechanical Systems (MEMS) Switches for Space Communications

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Ponchak, George E.; Scardelletti, Maximillian C.; Varaljay, Nicholas C.

    2000-01-01

    Micro-electromechanical systems (MEMS) is an emerging technology for radio frequency (RF) systems because it has the potential to dramatically decrease loss and improve efficiency. In this paper, we address the design and fabrication of novel MEMS switches being developed at NASA Glenn Research Center. Two types of switches are being developed: a microstrip series single pole single throw (SPST) switch and a coplanar waveguide (CPW) series SPST and single pole double throw (SPDT) switches. These are being fabricated as an integral part of 50 Ohm microstrip and CPW RF integrated circuits using microfabrication techniques. The construction of the switch relies on a cantilever beam that is partially supported by a dielectric post. The cantilever beam is electro-magnetically actuated. To decrease stiction, a Si3N4 thin film is deposited over the contact area. Thus, when the switch is closed, the ON-state insertion loss is governed by the parallel plate capacitance formed by the two contacts. The isolation in the OFF-state is governed by the parasitic capacitance when the cantilever is in the up position. RF MEMS switches have been demonstrated with 80% lower insertion loss than conventional solid state devices (GaAs Metal Semiconductor Field Effect Transistors (MESFETs) and Silicon PIN diodes) based switches. For example, a conventional GaAs five-bit phase shifter which is required for beam steering in a phased array antenna has approximately 7 dB of insertion loss at 26.5 GHz where as a comparable MEMS based phase shifter is expected to have only 2 dB of insertion loss. This translates into 56% lower power dissipation and therefore decreases the thermal load on the spacecraft and also reduces the power amplifier requirements. These benefits will enable NASA to build the next generation of deep space science crafts and micro/nano satellites.

  13. Evolution of the symbiotic binary system AG Dranconis

    NASA Technical Reports Server (NTRS)

    Mikolajewska, Joanna; Kenyon, Scott J; Mikolajewski, Maciej; Garcia, Michael R.; Polidan, Ronald S.

    1995-01-01

    We present an analysis of new and archival photometric and spectroscopic observations of the symbiotic star AG Draconis. This binary has undergone several 1 - 3 mag optical and ultraviolet eruptions during the past 15 years. Our combination of optical and ultraviolet spectroscopic data allow a more complete analysis of this system than in previous papers. AG Dra is composed of a K-type bright giant M(sub g) approximately 1.5 solar mass) and a hot, compact star M(sub h approximatelly 0.4 - 0.6 solar mass) embedded in a dense, low metallicity nebula. The hot component undergoes occasional thermonuclear runaways that produce 2 - 3 mag optical/ultraviolet eruptions. During these eruptions, the hot component develops a low velocity wind that quenches x-ray emission from the underlying hot white dwarf. The photoionized nebula changes its volume by a factor of 5 throughout an eruptin cycle. The K bright giant occults low ionization emission lines during superior conjunctions at all outburst phases but does not occult high ionization lines in outburst (and perhaps quiescence). This geometry and the component masses suggest a system inclination of i approximately 30 deg - 45 deg.

  14. System-in-package LTCC platform for 3D RF to millimeter wave

    NASA Astrophysics Data System (ADS)

    Vähä-Heikkilä, T.; Lahti, M.

    2011-04-01

    This presentation shows recent trends and results in 3D Low Temperature Co-Fired Ceramics (LTCC) modules in applications from RF to millimeter waves. The system-in-package LTCC platform is a true three dimensional module technology. LTCC is a lightweight multi-layer technology having typically 6-20 ceramic layers and metallizations between. The metallization levels i.e different metal layers can be patterned and connected together with metal vias. Passive devices can also be fabricated on LTCC while active devices and other chips are connected with flip-chip, wire bonding or soldering. In addition to passives directly fabricated to LTCC, several different technologies/ chips can be hybrid integrated to the same module. LTCC platform is also well suited for the realization of antenna arrays for microwave and millimeter wave applications. Potential applications are ranging from short range communications to space and radars. VTT has designed, fabricated and characterized microwave and millimeter wave packages for Radio Frequency (RF) Micro Electro Mechanical Systems (MEMS) as well as active devices. Also, several types of system-in-package modules have been realized containing hybrid integrated CMOS and GaAs MMICs and antenna arrays.

  15. The electromagnetic environment of Magnetic Resonance Imaging systems. Occupational exposure assessment reveals RF harmonics

    NASA Astrophysics Data System (ADS)

    Gourzoulidis, G.; Karabetsos, E.; Skamnakis, N.; Kappas, C.; Theodorou, K.; Tsougos, I.; Maris, T. G.

    2015-09-01

    Magnetic Resonance Imaging (MRI) systems played a crucial role in the postponement of the former occupational electromagnetic fields (EMF) European Directive (2004/40/EC) and in the formation of the latest exposure limits adopted in the new one (2013/35/EU). Moreover, the complex MRI environment will be finally excluded from the implementation of the new occupational limits, leading to an increased demand for Occupational Health and Safety (OHS) surveillance. The gradient function of MRI systems and the application of the RF excitation frequency result in low and high frequency exposures, respectively. This electromagnetic field exposure, in combination with the increased static magnetic field exposure, makes the MRI environment a unique case of combined EMF exposure. The electromagnetic field levels in close proximity of different MRI systems have been assessed at various frequencies. Quality Assurance (QA) & safety issues were also faced. Preliminary results show initial compliance with the forthcoming limits in each different frequency band, but also revealed peculiar RF harmonic components, of no safety concern, to the whole range detected (20-1000MHz). Further work is needed in order to clarify their origin and characteristics.

  16. RF characteristics of the hoop column antenna for the land mobile satellite system mission

    NASA Technical Reports Server (NTRS)

    Foldes, P.

    1984-01-01

    A communication system using a satellite with a 118 meter diameter quad aperture antenna to provide telephone service to mobile users remotely located from the large metropolitan areas where the telephone companies are presently implementing their cellular system is described. In this system, which is compatible with the cellular system, the mobile user communicates with the satellite at UHF frequencies. The satellite connects him at S-Band, to the existing telephone network via a base station. The results of the RF definition work for the quad aperture antenna are presented. The elements of the study requirements for the LMSS are summarized, followed by a beam topology plan which satisfies the mission requirements with a practical and realiable configuration. The geometry of the UHF antenna and its radiation characteristics are defined. The various feed alternatives, and the S-band aperture are described.

  17. RF characteristics of the hoop column antenna for the land mobile satellite system mission

    NASA Astrophysics Data System (ADS)

    Foldes, P.

    1984-11-01

    A communication system using a satellite with a 118 meter diameter quad aperture antenna to provide telephone service to mobile users remotely located from the large metropolitan areas where the telephone companies are presently implementing their cellular system is described. In this system, which is compatible with the cellular system, the mobile user communicates with the satellite at UHF frequencies. The satellite connects him at S-Band, to the existing telephone network via a base station. The results of the RF definition work for the quad aperture antenna are presented. The elements of the study requirements for the LMSS are summarized, followed by a beam topology plan which satisfies the mission requirements with a practical and realiable configuration. The geometry of the UHF antenna and its radiation characteristics are defined. The various feed alternatives, and the S-band aperture are described.

  18. Development of simple designs of multitip probe diagnostic systems for RF plasma characterization.

    PubMed

    Naz, M Y; Shukrullah, S; Ghaffar, A; Rehman, N U

    2014-01-01

    Multitip probes are very useful diagnostics for analyzing and controlling the physical phenomena occurring in low temperature discharge plasmas. However, DC biased probes often fail to perform well in processing plasmas. The objective of the work was to deduce simple designs of DC biased multitip probes for parametric study of radio frequency plasmas. For this purpose, symmetric double probe, asymmetric double probe, and symmetric triple probe diagnostic systems and their driving circuits were designed and tested in an inductively coupled plasma (ICP) generated by a 13.56 MHz radio frequency (RF) source. Using I-V characteristics of these probes, electron temperature, electron number density, and ion saturation current was measured as a function of input power and filling gas pressure. An increasing trend was noticed in electron temperature and electron number density for increasing input RF power whilst a decreasing trend was evident in these parameters when measured against filling gas pressure. In addition, the electron energy probability function (EEPF) was also studied by using an asymmetric double probe. These studies confirmed the non-Maxwellian nature of the EEPF and the presence of two groups of the energetic electrons at low filling gas pressures.

  19. Development of Simple Designs of Multitip Probe Diagnostic Systems for RF Plasma Characterization

    PubMed Central

    Naz, M. Y.; Shukrullah, S.; Ghaffar, A.; Rehman, N. U.

    2014-01-01

    Multitip probes are very useful diagnostics for analyzing and controlling the physical phenomena occurring in low temperature discharge plasmas. However, DC biased probes often fail to perform well in processing plasmas. The objective of the work was to deduce simple designs of DC biased multitip probes for parametric study of radio frequency plasmas. For this purpose, symmetric double probe, asymmetric double probe, and symmetric triple probe diagnostic systems and their driving circuits were designed and tested in an inductively coupled plasma (ICP) generated by a 13.56 MHz radio frequency (RF) source. Using I-V characteristics of these probes, electron temperature, electron number density, and ion saturation current was measured as a function of input power and filling gas pressure. An increasing trend was noticed in electron temperature and electron number density for increasing input RF power whilst a decreasing trend was evident in these parameters when measured against filling gas pressure. In addition, the electron energy probability function (EEPF) was also studied by using an asymmetric double probe. These studies confirmed the non-Maxwellian nature of the EEPF and the presence of two groups of the energetic electrons at low filling gas pressures. PMID:24683326

  20. Functional and Expression Analysis of the Metal-Inducible dmeRF System from Rhizobium leguminosarum bv. viciae

    PubMed Central

    Rubio-Sanz, L.; Prieto, R. I.; Imperial, J.; Brito, B.

    2013-01-01

    A gene encoding a homolog to the cation diffusion facilitator protein DmeF from Cupriavidus metallidurans has been identified in the genome of Rhizobium leguminosarum UPM791. The R. leguminosarum dmeF gene is located downstream of an open reading frame (designated dmeR) encoding a protein homologous to the nickel- and cobalt-responsive transcriptional regulator RcnR from Escherichia coli. Analysis of gene expression showed that the R. leguminosarum dmeRF genes are organized as a transcriptional unit whose expression is strongly induced by nickel and cobalt ions, likely by alleviating the repressor activity of DmeR on dmeRF transcription. An R. leguminosarum dmeRF mutant strain displayed increased sensitivity to Co(II) and Ni(II), whereas no alterations of its resistance to Cd(II), Cu(II), or Zn(II) were observed. A decrease of symbiotic performance was observed when pea plants inoculated with an R. leguminosarum dmeRF deletion mutant strain were grown in the presence of high concentrations of nickel and cobalt. The same mutant induced significantly lower activity levels of NiFe hydrogenase in microaerobic cultures. These results indicate that the R. leguminosarum DmeRF system is a metal-responsive efflux mechanism acting as a key element for metal homeostasis in R. leguminosarum under free-living and symbiotic conditions. The presence of similar dmeRF gene clusters in other Rhizobiaceae suggests that the dmeRF system is a conserved mechanism for metal tolerance in legume endosymbiotic bacteria. PMID:23934501

  1. Functional and expression analysis of the metal-inducible dmeRF system from Rhizobium leguminosarum bv. viciae.

    PubMed

    Rubio-Sanz, L; Prieto, R I; Imperial, J; Palacios, J M; Brito, B

    2013-10-01

    A gene encoding a homolog to the cation diffusion facilitator protein DmeF from Cupriavidus metallidurans has been identified in the genome of Rhizobium leguminosarum UPM791. The R. leguminosarum dmeF gene is located downstream of an open reading frame (designated dmeR) encoding a protein homologous to the nickel- and cobalt-responsive transcriptional regulator RcnR from Escherichia coli. Analysis of gene expression showed that the R. leguminosarum dmeRF genes are organized as a transcriptional unit whose expression is strongly induced by nickel and cobalt ions, likely by alleviating the repressor activity of DmeR on dmeRF transcription. An R. leguminosarum dmeRF mutant strain displayed increased sensitivity to Co(II) and Ni(II), whereas no alterations of its resistance to Cd(II), Cu(II), or Zn(II) were observed. A decrease of symbiotic performance was observed when pea plants inoculated with an R. leguminosarum dmeRF deletion mutant strain were grown in the presence of high concentrations of nickel and cobalt. The same mutant induced significantly lower activity levels of NiFe hydrogenase in microaerobic cultures. These results indicate that the R. leguminosarum DmeRF system is a metal-responsive efflux mechanism acting as a key element for metal homeostasis in R. leguminosarum under free-living and symbiotic conditions. The presence of similar dmeRF gene clusters in other Rhizobiaceae suggests that the dmeRF system is a conserved mechanism for metal tolerance in legume endosymbiotic bacteria.

  2. Development of Cs 2Te photocathode rf gun system for compact THz SASE-FEL

    NASA Astrophysics Data System (ADS)

    Kuroda, R.; Ogawa, H.; Sei, N.; Toyokawa, H.; Yagi-Watanabe, K.; Yasumoto, M.; Koike, M.; Yamada, K.; Yanagida, T.; Nakajyo, T.; Sakai, F.

    2008-08-01

    A compact terahertz (THz) SASE-FEL source has been developed with a compact S-band electron linac at AIST. The S-band linac has been improved using a Cs 2Te photocathode rf gun with a compact load-lock system. The 40 MeV electron beam which has a bunch charge of more than 2 nC/bunch was stably generated using our system with the Cs 2Te photocathode, and the quantum efficiency (QE) typically achieved was about 0.3%. The surface observation of the Cs 2Te photocathode to obtain the surface micrographs and QE mapping images was successfully performed with a photoelectron emission microscopy (PEEM).

  3. RF System Requirements for a Medium-Energy Electron-Ion Collider (MEIC) at JLab

    SciTech Connect

    Rimmer, Robert A; Hannon, Fay E; Guo, Jiquan; Huang, Shichun; Huang, Yulu; Wang, Haipeng; Wang, S

    2015-09-01

    JLab is studying options for a medium energy electron-ion collider that could fit on the JLab site and use CEBAF as a full-energy electron injector. A new ion source, linac and booster would be required, together with collider storage rings for the ions and electrons. In order to achieve the maximum luminosity these will be high-current storage rings with many bunches. We present the high-level RF system requirements for the storage rings, ion booster ring and high-energy ion beam cooling system, and describe the technology options under consideration to meet them. We also present options for staging that might reduce the initial capital cost while providing a smooth upgrade path to a higher final energy. The technologies under consideration may also be useful for other proposed storage ring colliders or ultimate light sources.

  4. A low-frequency high-voltage rf-barrier-bunching system for high-intensity neutron source compressor rings

    SciTech Connect

    Hardek, T.W.; Ziomek, C.; Rees, D.

    1995-05-01

    A Los Alamos design for a 1-MW pulsed neutron source incorporates a ring utilizing an rf-barrier bunching system. This bunching concept allows uniform longitudinal beam distributions with low momentum spread. Bunching cavities are operated at the revolution frequency (1.5 MHz in this case) and each of the 2nd, 3rd, 4th, and 5th revolution frequency harmonics. Their effects combine to maintain a beam free gap in the longitudinal distribution of the accumulated beam. The cavities are driven by low-plate-resistance common-cathode configured retrode amplifiers incorporating local rf feedback. Additional adaptive feed-forward hardware is included to reduce the beam-induced bunching-gap voltages well below that achievable solely with rf feedback. Details of this system are presented along with a discussion of the various feed-back and feed-forward techniques incorporated.

  5. Beamloading compensation of the rf system for the storage ring of the advanced photon source (APS)

    NASA Astrophysics Data System (ADS)

    Bridges, J.; Stepp, J.

    1994-10-01

    A brief overview of the rf system is given. Design and operating parameters for the klystron amplifiers powering the single cell cavities are described with operating parameters for various positron beam intensities and for optimization of the feedback loops. Klystron efficiencies are low except in saturated operation, but any feedback loop around the klystron requires at least some klystron gain. The gain in the amplitude feedback loop must be adjusted to compensate for saturation. The operating point of the klystron may be dynamically adjusted through a pre-programmed computer or dedicated local processor. Feed forward techniques may be used to alter the program based on beam intensity over the ten-hour storage cycle, using a new digitizer module from Hewlett-Packard. Reduction of the cavity impedance for multi-bunch operation is also described.

  6. Installation of spectrally selective imaging system in RF negative ion source.

    PubMed

    Ikeda, K; Wünderlich, D; Fantz, U; Heinemann, B; Kisaki, M; Nagaoka, K; Nakano, H; Osakabe, M; Tsumori, K; Geng, S; Kaneko, O; Takeiri, Y

    2016-02-01

    A spectrally selective imaging system has been installed in the RF negative ion source in the International Thermonuclear Experimental Reactor-relevant negative ion beam test facility ELISE (Extraction from a Large Ion Source Experiment) to investigate distribution of hydrogen Balmer-α emission (Hα) close to the production surface of hydrogen negative ion. We selected a GigE vision camera coupled with an optical band-path filter, which can be controlled remotely using high speed network connection. A distribution of Hα emission near the bias plate has been clearly observed. The same time trend on Hα intensities measured by the imaging diagnostic and the optical emission spectroscopy is confirmed. PMID:26931995

  7. The upgraded ring loss radiation monitorinng system at the AGS

    SciTech Connect

    Bennett, G.W.; Beadle, E.; Castille, V.; Witkover, R.L.

    1989-01-01

    With the Booster the AGS will accelerate protons to 3 /times/ 10/sup 13/ per cycle, polarized protons at 10/sup 12/, and ions from Carbon to Gold at intensities from 50 to 3 /times/ 10/sup 9/. A loss monitoring system is being developed to facilitate tuning, and to reduce personnel radiation exposure by minimizing residual induced activity and by allowing remote monitoring of activity in the accelerator enclosure. The monitoring system must have a large dynamic range to monitor high intensity beam losses and to measure induced activity down to the level of a few mrad/hour. Various detectors are being evaluated, including ion chambers, proportional counters, and aluminium cathode electronmultipliers. Measurements of the prompt ionization distribution in the median plane at various energies from point targets at two representative locations in the accelerator lattice have been completed. Details of the monitoring system will be presented, as well as the experimental measurements of the prompt radiation field, and a comparable Monte Carlo calculation. 2 refs., 5 figs.

  8. An Optically-Coupled System for Quantitative Monitoring of MRI-Induced RF Currents into Long Conductors

    PubMed Central

    Zanchi, Marta G.; Venook, Ross; Pauly, John M.; Scott, Greig C.

    2010-01-01

    The currents induced in long conductors such as guidewires by the radio frequency (RF) field in magnetic resonance imaging (MRI) are responsible for potentially dangerous heating of surrounding media, such as tissue. This paper presents an optically-coupled system with the potential to quantitatively measure the RF currents induced on these conductors. The system uses a self shielded toroid transducer and active circuitry to modulate a high speed LED transmitter. Plastic fiber guides the light to a photodiode receiver and transimpedance amplifier. System validation included a series of experiments with bare wires that compared wire tip heating by fluoroptic thermometers with the RF current sensor response. Validations were performed on a custom whole body 64 MHz birdcage test platform and on a 1.5T MRI scanner. With this system, a variety of phenomena were demonstrated including cable trap current attenuation, lossy dielectric Q-spoiling and even transverse electromagnetic wave node patterns. This system should find applications in studies of MRI RF safety for interventional devices such as pacemaker leads, and guidewires. In particular, variations of this device could potentially act as a realtime safety monitor during MRI guided interventions. PMID:19758855

  9. Transparent Conductive AGZO/Ag/AGZO Multilayers on PET Substrate by Roll-to-Roll Sputtering.

    PubMed

    Kim, Taehoon; Park, Kwangwon; Kim, Jongsu

    2016-02-01

    Indium-free Al and Ga-codoped ZnO (AGZO) multilayer films with nanoscale Ag interlayer were deposited by dual target roll-to-roll RF for AGZO and DC sputtering systems for Ag at room temperature for a large scale. The thicknesses of AGZO/Ag/AGZO multilayer were optimized by changing the roll speed: 0.15/1.1/0.15 m/min for AGZO/Ag/AGZO multilayers, respectively. The optimum thicknesses of AGZO/Ag/AGZO multilayer are 9.21, 8.32 and 8.04 nm, respectively. Optimized AGZO/Ag/AGZO multilayer films showed an excellent transparency (84% at 550 nm) and a low sheet resistance (9.2 omega/sq.) on PET substrates for opto-electronic applications. The effects of nanoscale Ag interlayer on optical and electrical properties of AGZO/Ag/AGZO multilayer films were discussed.

  10. Transparent Conductive AGZO/Ag/AGZO Multilayers on PET Substrate by Roll-to-Roll Sputtering.

    PubMed

    Kim, Taehoon; Park, Kwangwon; Kim, Jongsu

    2016-02-01

    Indium-free Al and Ga-codoped ZnO (AGZO) multilayer films with nanoscale Ag interlayer were deposited by dual target roll-to-roll RF for AGZO and DC sputtering systems for Ag at room temperature for a large scale. The thicknesses of AGZO/Ag/AGZO multilayer were optimized by changing the roll speed: 0.15/1.1/0.15 m/min for AGZO/Ag/AGZO multilayers, respectively. The optimum thicknesses of AGZO/Ag/AGZO multilayer are 9.21, 8.32 and 8.04 nm, respectively. Optimized AGZO/Ag/AGZO multilayer films showed an excellent transparency (84% at 550 nm) and a low sheet resistance (9.2 omega/sq.) on PET substrates for opto-electronic applications. The effects of nanoscale Ag interlayer on optical and electrical properties of AGZO/Ag/AGZO multilayer films were discussed. PMID:27433648

  11. Microfluidic stretchable RF electronics.

    PubMed

    Cheng, Shi; Wu, Zhigang

    2010-12-01

    Stretchable electronics is a revolutionary technology that will potentially create a world of radically different electronic devices and systems that open up an entirely new spectrum of possibilities. This article proposes a microfluidic based solution for stretchable radio frequency (RF) electronics, using hybrid integration of active circuits assembled on flex foils and liquid alloy passive structures embedded in elastic substrates, e.g. polydimethylsiloxane (PDMS). This concept was employed to implement a 900 MHz stretchable RF radiation sensor, consisting of a large area elastic antenna and a cluster of conventional rigid components for RF power detection. The integrated radiation sensor except the power supply was fully embedded in a thin elastomeric substrate. Good electrical performance of the standalone stretchable antenna as well as the RF power detection sub-module was verified by experiments. The sensor successfully detected the RF radiation over 5 m distance in the system demonstration. Experiments on two-dimensional (2D) stretching up to 15%, folding and twisting of the demonstrated sensor were also carried out. Despite the integrated device was severely deformed, no failure in RF radiation sensing was observed in the tests. This technique illuminates a promising route of realizing stretchable and foldable large area integrated RF electronics that are of great interest to a variety of applications like wearable computing, health monitoring, medical diagnostics, and curvilinear electronics.

  12. HIGH ENERGY PULSED POWER SYSTEM FOR AGS SUPER NEUTRINO FOCUSING HORN.

    SciTech Connect

    ZHANG, S.Y.; SANDBERG, J.; WENG, W.-T.

    2005-05-16

    This paper present a preliminary design of a 300 kA, 2.5 Hz pulsed power system. This system will drive the focusing horn of proposed Brookhaven AGS Neutrino Super Beam Facility for Very Long Baseline Neutrino Oscillation Experiment. The peak output power of the horn pulsed power system will reach Giga-watts, and the upgraded AGS will be capable of delivering 1 MW in beam power.

  13. Single electron beam rf feedback free electron laser

    DOEpatents

    Brau, C.A.; Stein, W.E.; Rockwood, S.D.

    1981-02-11

    A free electron laser system and electron beam system for a free electron laser which uses rf feedback to enhance efficiency are described. Rf energy is extracted from a single electron beam by decelerating cavities and energy is returned to accelerating cavities using rf returns, such as rf waveguides, rf feedthroughs, resonant feedthroughs, etc. This rf energy is added to rf klystron energy to reduce the required input energy and thereby enhance energy efficiency of the system.

  14. Magnetic trapping of silver and copper, and anomalous spin relaxation in the ag-he system.

    PubMed

    Brahms, Nathan; Newman, Bonna; Johnson, Cort; Greytak, Tom; Kleppner, Daniel; Doyle, John

    2008-09-01

    We have trapped large numbers of copper (Cu) and silver (Ag) atoms using buffer-gas cooling. Up to 3 x 10{12} Cu atoms and 4 x 10{13} Ag atoms are trapped. Lifetimes are as long as 5 s, limited by collisions with the buffer gas. Ratios of elastic to inelastic collision rates with He are >or=10{6}, suggesting Cu and Ag are favorable for use in ultracold applications. The temperature dependence of the Ag-3He collision rate varies as T;{5.8+/-0.4}. We find that this temperature dependence is inconsistent with the behavior predicted for relaxation arising from the spin-rotation interaction, and conclude that the Ag-3He system displays anomalous collisional behavior in the multiple-partial wave regime. Gold (Au) was ablated into 3He buffer gas, however, atomic Au lifetimes were observed to be too short to permit trapping.

  15. An amplitude and phase control system for the TFTR rf heating sources

    SciTech Connect

    Cutsogeorge, G.

    1989-04-01

    Feedback loops that control the amplitude and phase of the rf heating sources on TFTR are described. The method for providing arc protection is also discussed. Block diagrams and Bode plots are included. 6 figs.

  16. An Optimized 2.4GHz RF Power Amplifier Performance for WLAN System

    NASA Astrophysics Data System (ADS)

    Ali, Mohammed H.; Chakrabarty, C. K.; Abdalla, Ahmed N.; Hock, Goh C.

    2013-06-01

    Recently, the design of RF power amplifiers (PAs) for modern wireless systems are faced with a difficult tradeoff for example, cellphone; battery lifetime is largely determined by the power efficiency of the PA and high spectral efficiency which have ability to transmit data at the highest possible rate for a given channel bandwidth. This paper presents the design a multi stage class AB power Amplifier with high power added efficiency (PAE) and acceptable linearity for the WLAN applications. The open-circuited third harmonic control circuit enhances the efficiency of the PA without deteriorating the linearity of class-AB mode of the PA. The voltage and current waveforms are simulated to evaluate the appropriate operation for the modes. The effectiveness of the proposed controller has been verified by comparing proposed method with another methods using simulation study under a variety of conditions. The proposed circuit operation for a WLAN signals delivers a power-added efficiency (PAE) of 37.6% is measured at 31.6-dBm output power while dissipating 34.61 mA from a 1.8V supply. Finally, the proposed PA is show a good and acceptable result for the WLAN system.

  17. RF systems in space. Volume 1: Space antennas frequency (SARF) simulation

    NASA Astrophysics Data System (ADS)

    Ludwig, A. C.; Freeman, J. R.; Capp, J. D.

    1983-04-01

    The main objective of this effort was to develop a computer based analytical capability for simulating the RF performance of large space-based radar (SBR) systems. The model is capable of simulating corporate and space fed aperture. The model also can simulate multibeam feeds, cluster/point feeds, corporate feed and various aperture distributions. The simulation is capable of accepting Draper Labs structural data and antenna current data from Atlantic Research Corporation's (ARC) First Approximation Methods (FAM) and Higher Approximation Methods (HAM) models. In addition there is a routine to input various apertures surface distortions which causes the elements in the array to be displaced from the ideal location on a planar lattice. These were analyses looking at calibration/compensation techniques for large aperture space radars. Passive, space fed lens SBR designs were investigated. The survivability of an SBR system was analyzed. The design of ground based SBR validation experiments for large aperture SBR concepts were investigated. SBR designs were investigated for ground target detection.

  18. Chemical and phase distributions in a multilayered organic matter-Ag nanoparticle thin film system

    NASA Astrophysics Data System (ADS)

    Michel, F. M.; Levard, C.; Wang, Y.; Choi, Y.; Eng, P.; Brown, G. E.

    2010-12-01

    Rapid development of nanotechnologies raises concern regarding the environmental impact of nanoparticles on ecosystems. Among the types of nanoparticles currently in production, metallic silver is the most widely used in nanotechnology (1). Synthetic Ag nanoparticles (Ag-NPs) are most often used for their antimicrobial and antifungal properties that are, in part, explained by the release of highly toxic Ag+ species (2). While such properties are desirable in certain applied cases, the release of Ag-NPs and soluble Ag+ species to the environment is expected to impact biota as well as soil and water quality (3). With the production of Ag-NPs projected to increase (1), the amount of Ag-NPs that will be released to the environment through waste streams is also likely to increase. As such, a deeper understanding of the fundamental processes associated with Ag-NPs toxicity and reactivity is needed to evaluate their impact on the environment. We have studied the interaction during aging of poly-acrylic acid (PAA) and Ag-NPs with average particle sizes of 20 ±5 nm. The sample studied was composed of thin films of PAA and Ag-NPs deposited on a Si-wafer support. PAA served as a model compound and a simplified surrogate for exopolysaccharide, an organic substance produced through metabolic activity by most microorganisms. We applied a novel combination of long-period x-ray standing wave fluorescence yield (XSW-FY) spectroscopy, grazing-incidence x-ray diffraction (GI-XRD), and XRD-based standing wave profiles (XSW-XRD) to obtain chemical- and phase-specific information on this sample. After 24 hours, we observed the formation of AgCl(s) in the PAA film of the sample, which suggests oxidation and dissolution of a portion of the Ag-NPs during aging, resulting in the release of Ag+. In addition, we see partitioning of Cl and Br, both present initially in the PAA, to the intact Ag-NPs thin film. To our knowledge, this is the first application of this suite of techniques to this

  19. Design and evaluation of a low-level RF control system analog/digital receiver for the ILC main Linacs

    SciTech Connect

    Mavric, Uros; Vidmar, Matjaz; Chase, Brian; /Fermilab

    2008-06-01

    The proposed RF distribution scheme for the two 15 km long ILC LINACs, uses one klystron to feed 26 superconducting RF cavities operating at 1.3 GHz. For a precise control of the vector sum of the signals coming from the SC cavities, the control system needs a high performance, low cost, reliable and modular multichannel receiver. At Fermilab we developed a 96 channel, 1.3 GHz analog/digital receiver for the ILC LINAC LLRF control system. In the paper we present a balanced design approach to the specifications of each receiver section, the design choices made to fulfill the goals and a description of the prototyped system. The design is tested by measuring standard performance parameters, such as noise figure, linearity and temperature sensitivity. Measurements show that the design meets the specifications and it is comparable to other similar systems developed at other laboratories, in terms of performance.

  20. High temperature metal purification using a compact portable rf heating and levitation system on the wake shield

    NASA Technical Reports Server (NTRS)

    Hahs, C. A.

    1990-01-01

    The Wake Shield Facility (WSF) can provide an ideal vacuum environment for the purification of high temperature metals in space. The Modular Electromagnetic Levitator (MEL), will provide the opportunity to study undercooling of metals in space and allow to determine material properties in space. The battery powered rf levitation and heating system developed for the MEL demonstrated efficiency of 36 percent. This system is being considered to purify metals at temperatures below 3000 C.

  1. 500 MW X-Band RF System of a 0.25 GeV Electron LINAC for Advanced Compton Scattering Source Application

    SciTech Connect

    Chu, Tak Sum; Anderson, Scott; Barty, Christopher; Gibson, David; Hartemann, Fred; Marsh, Roark; Siders, Craig; Adolphsen, Chris; Jongewaard, Erik; Raubenheimer, Tor; Tantawi, Sami; Vlieks, Arnold; Wang, Juwen; /SLAC

    2012-07-03

    A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL in collaboration with the SLAC National Accelerator Laboratory. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW, 1.5 msec pulses, will be the main high power RF sources for the system. These klystrons will be powered by state of the art solid-state high voltage modulators. A RF pulse compressor, similar to the SLED II pulse compressor, will compress the klystron output pulse with a power gain factor of five. For compactness consideration, we are looking at a folded waveguide setup. This will give us 500 MW at output of the compressor. The compressed pulse will then be distributed to the RF gun and to six traveling wave accelerator sections. Phase and amplitude control are located at the RF gun input and additional control points along the LINAC to allow for parameter control during operation. This high power RF system is being designed and constructed. In this paper, we will present the design, layout, and status of this RF system.

  2. 500 MW X-BAND RF SYSTEM OF A 0.25 GEV ELECTRON LINAC FOR ADVANCED COMPTON SCATTERING SOURCE APPLICATION

    SciTech Connect

    Chu, T S; Anderson, S G; Gibson, D J; Hartemann, F V; Marsh, R A; Siders, C; Barty, C P; Adolphsen, C; Jongewaard, E; Tantawi, S; Vlieks, A; Wang, J W; Raubenheimer, T

    2010-05-12

    A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL in collaboration with SLAC National Accelerator Laboratory. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW, 1.5 msec pulses, will be the main high power RF sources for the system. These klystrons will be powered by state of the art solid-state high voltage modulators. A RF pulse compressor, similar to the SLED II pulse compressor, will compress the klystron output pulse with a power gain factor of five. For compactness consideration, we are looking at a folded waveguide setup. This will give us 500 MW at output of the compressor. The compressed pulse will then be distributed to the RF gun and to six traveling wave accelerator sections. Phase and amplitude control are located at the RF gun input and additional control points along the LINAC to allow for parameter control during operation. This high power RF system is being designed and constructed. In this paper, we will present the design, layout, and status of this RF system.

  3. Fiber-optic link for the RF phase reference distribution system for the XFEL and TESLA projects

    NASA Astrophysics Data System (ADS)

    Czuba, Krzysztof; Eints, Frank; Felber, Matthias; Simrock, Stefan

    2005-02-01

    The UV Free-Electron Laser (UVFEL) and The TeV-Energy Superconducting Linear Accelerator (TESLA) projects will require phase synchronization of 0.1 ps short term (millisecond), 1 ps short term (minutes) and 10 ps long term (days). The stringent synchronization requirement of 10fs was given for the X-Ray Free- Electron Laser (XFEL). To fufill this requirement the XFEL may use a fiber laser as reference generator. But this requirement applies for a special location only, therefore the RF phase reference distribution system developed UVFEL and TESLA will also be used in the XFEL. The RF phase reference distribution system must deliver phase stable signals to hundreds of stations over a length of 33 km. Long, optical fiber based links are planned to be an important part of the entire distribution system. This paper describes the concept of a long optical link, with a feedback system suppressing long term drifts of the RF signal phase. Stability requirements are given and most important design issues affecting system performance are discussed. Finally, an experimental setup and measurement results demonstrating system performance is shown.

  4. Low temperature vitrification of radioiodine using AgI-Ag{sub 2}O-P{sub 2}O{sub 5} glass system

    SciTech Connect

    Fujihara, H.; Murase, T.; Nishi, T.; Noshita, K. Yoshida, T.; Matsuda, M.

    1999-07-01

    A new vitrification process for radioiodine has been developed for safe disposal of the spent iodine adsorbent generated from reprocessing off-gas systems. The proposed process consists of the following two steps: (1) separation of radioiodine as AgI from spent iodine adsorbent and (2) vitrification of the separated AgI with silver phosphate. An AgI-Ag{sub 2}O-P{sub 2}O{sub 5} glass system can homogeneously contain up to 60 mol% AgI, which leads to high volume reduction efficiency (approximately 1/25). It also can vitrify the AgI without volatilization of iodine because of its low melting temperature (below 400 C). The leachabilities of iodine from simulated vitrified waste forms were evaluated by the MCC-1 static leach test in an anaerobically controlled glove box, which was purged by nitrogen gas with 3% hydrogen. The leaching behavior of the AgI-Ag{sub 2}O-P{sub 2}O{sub 5} glass system was influenced by the composition of the actual glass, type of leachant, and redox conditions. When the leach test was carried out using simulated ground water originating from rainfall, the leach rate of iodine from 3AgI-Ag{sub 4}P{sub 2}O{sub 7} glass was 6 x 10{sup {minus}8}g/cm{sup 2}/d in the early period of the leach test at 35 C under the reducing condition, after which it decreased to 3 x 10{sup {minus}9}g/cm{sup 2}/d. This glass showed a lower leach rate in the simulated ground water originating from sea water or cement saturated water, since a precipitation layer was formed on the surface.

  5. RF Sources for the ITER Ion Cyclotron Heating and Current Drive System

    SciTech Connect

    Hosea, J.; Brunkhorst, C.; Fredd, E.; Goulding, R. H.; Goulding, R. H.; Greenough, N.; Kung, C.; Rasmussen, D. A.; Swain, D. W.; Wilson, J. R.

    2005-10-04

    The RF source requirements for the ITER ion cyclotron (IC) heating and current drive system are very challenging ? 20 MW CW power into an antenna load with a VSWR of up to 2 over the frequency range of 35-65 MHz. For the two present antenna designs under consideration, 8 sources providing 2.5 MW each are to be employed. For these sources, the outputs of two final power amplifiers (FPAs), using the high power CPI 4CM2500KG tube, are combined with a 180? hybrid combiner to easily meet the ITER IC source requirements ? 2.5 MW is supplied at a VSWR of 2 at ? 70% of the maximum tube power available in class B operation. The cylindrical cavity configuration for the FPAs is quite compact so that the 8 combined sources fit into the space allocated at the ITER site with room to spare. The source configuration is described in detail and its projected operating power curves are presented. Although the CPI tube has been shown to be stable under high power operating conditions on many facilities, a test of the combined FPA source arrangement is in preparation using existing high power 30 MHz amplifiers to assure that this configuration can be made robustly stable for all phases at a VSWR up to 2. The possibility of using 12 sources to feed a suitably modified antenna design is also discussed in the context of providing flexibility for specifying the final IC antenna design.

  6. Global optimization of bimetallic cluster structures. II. Size-matched Ag-Pd, Ag-Au, and Pd-Pt systems.

    PubMed

    Rossi, Giulia; Ferrando, Riccardo; Rapallo, Arnaldo; Fortunelli, Alessandro; Curley, Benjamin C; Lloyd, Lesley D; Johnston, Roy L

    2005-05-15

    Genetic algorithm global optimization of Ag-Pd, Ag-Au, and Pd-Pt clusters is performed. The 34- and 38-atom clusters are optimized for all compositions. The atom-atom interactions are modeled by a semiempirical potential. All three systems are characterized by a small size mismatch and a weak tendency of the larger atoms to segregate at the surface of the smaller ones. As a result, the global minimum structures exhibit a larger mixing than in Ag-Cu and Ag-Ni clusters. Polyicosahedral structures present generally favorable energetic configurations, even though they are less favorable than in the case of the size-mismatched systems. A comparison between all the systems studied here and in the previous paper (on size-mismatched systems) is presented.

  7. A dual RF resonator system for high-field functional magnetic resonance imaging of small animals.

    PubMed

    Ludwig, R; Bodgdanov, G; King, J; Allard, A; Ferris, C F

    2004-01-30

    A new apparatus has been developed that integrates an animal restrainer arrangement for small animals with an actively tunable/detunable dual radio-frequency (RF) coil system for in vivo anatomical and functional magnetic resonance imaging of small animals at 4.7 T. The radio-frequency coil features an eight-element microstrip line configuration that, in conjunction with a segmented outer copper shield, forms a transversal electromagnetic (TEM) resonator structure. Matching and active tuning/detuning is achieved through fixed/variable capacitors and a PIN diode for each resonator element. These components along with radio-frequency chokes (RFCs) and blocking capacitors are placed on two printed circuit boards (PCBs) whose copper coated ground planes form the front and back of the volume coil and are therefore an integral part of the resonator structure. The magnetic resonance signal response is received with a dome-shaped single-loop surface coil that can be height-adjustable with respect to the animal's head. The conscious animal is immobilized through a mechanical arrangement that consists of a Plexiglas body tube and a head restrainer. This restrainer has a cylindrical holder with a mouthpiece and position screws to receive and restrain the head of the animal. The apparatus is intended to perform anatomical and functional magnetic resonance imaging in conscious animals such as mice, rats, hamsters, and marmosets. Cranial images acquired from fully conscious rats in a 4.7 T Bruker 40 cm bore animal scanner underscore the feasibility of this approach and bode well to extend this system to the imaging of other animals. PMID:14706710

  8. Measurement of the thermodynamic properties of saturated solid solutions of compounds in the Ag-Sn-Se system by the EMF method

    NASA Astrophysics Data System (ADS)

    Moroz, M. V.; Prokhorenko, M. V.

    2015-08-01

    The dependence of the EMF ( E) of galvanic cells Ag|AgI|Ag2GeS3 glass| D on temperature (where Ag, D denotes the electrodes of an electrochemical cell; D represents equilibrium two- and three-phase alloys of the Ag-Sn-Se system; and AgI|Ag2GeS3 glass is a bilayer membrane with purely ionic (Ag+) conductivity) is studied in the range of 480-580 K. Analytical equations of E( T) are used to calculate the values of the thermodynamic functions of saturated solid solutions of the SnSe, β-Ag2Se, AgSnSe2, and Ag8SnSe6 phases of the Ag-Sn-Se system in the standard state.

  9. High temperature phase equilibria studies in the Bi-Sr-Ca-Cu-O-Ag system

    SciTech Connect

    Margulies, Lawrence

    1999-11-08

    A variety of experimental techniques were utilized to examine the high temperature phase equilibria in the Bi-Sr-Ca-Cu-O-Ag system. Quenching studies were used to determine the liquid solubility of Ag in the Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} (Bi2212) melt and the details of the peritectic decomposition pathway of Bi2212 as a function on Ag content and oxygen partial pressure (PO{sub 2}). A liquid immiscibility region between oxide and Ag liquids in the 8--98 at% range was found above 900 C. Two eutectics were found in the Bi2212-Ag pseudobinary. On the oxide rich side, a eutectic exists at approximately 4 at% Ag. On the Ag rich side, a eutectic exists at approximately 98 at% Ag at a temperature of 15 C below the melting point of pure Ag. Six distinct solid phases were found to be in equilibrium with the partial melt within the Ag content and PO{sub 2} range studied. The stability of these solid phases were found to be highly sensitive to PO{sub 2}, and to a much lesser extent Ag content. High temperature x-ray diffraction (HTXRD) studies of this system are in conflict with these results. It is suggested that these discrepancies are due to experimental artifacts caused by the significant thermal gradients and lack of full bulk sampling which is inherent in conventional HTXRD designs. In part 2, a new furnace design compatible with synchrotron radiation sources is introduced to address these problems. This design allows for full bulk sampling in a low thermal gradient environment using Debye-Scherrer transmission geometry. Sample spinning is also introduced in the design to eliminate preferred orientation and incomplete powder averaging and allow for quantitative phase analysis and structural refinement. Studies on model systems are presented to demonstrate the capabilities for high resolution structural studies (Al{sub 2}O{sub 3}) and time resolved phase transformation studies (SrCO{sub 3}). Finally, the Bi2212 system is examined to confirm the quenching results

  10. RF interference suppression in a cardiac synchronization system operating in a high magnetic field NMR imaging system

    SciTech Connect

    Damji, A.A.; Snyder, R.E.; Ellinger, D.C.; Witkowski, F.X.; Allen, P.S.

    1988-11-01

    An electrocardiographic (ECG) unit suitable for cardiac-synchronized nuclear magnetic resonance imaging in high magnetic fields is presented. The unit includes lossy transmission lines as ECG leads in order to suppress radio frequency (RF) interference in the electrocardiogram. The unit's immunity to RF interference is demonstrated.

  11. An RF energy harvester system using UHF micropower CMOS rectifier based on a diode connected CMOS transistor.

    PubMed

    Shokrani, Mohammad Reza; Khoddam, Mojtaba; Hamidon, Mohd Nizar B; Kamsani, Noor Ain; Rokhani, Fakhrul Zaman; Shafie, Suhaidi Bin

    2014-01-01

    This paper presents a new type diode connected MOS transistor to improve CMOS conventional rectifier's performance in RF energy harvester systems for wireless sensor networks in which the circuits are designed in 0.18  μm TSMC CMOS technology. The proposed diode connected MOS transistor uses a new bulk connection which leads to reduction in the threshold voltage and leakage current; therefore, it contributes to increment of the rectifier's output voltage, output current, and efficiency when it is well important in the conventional CMOS rectifiers. The design technique for the rectifiers is explained and a matching network has been proposed to increase the sensitivity of the proposed rectifier. Five-stage rectifier with a matching network is proposed based on the optimization. The simulation results shows 18.2% improvement in the efficiency of the rectifier circuit and increase in sensitivity of RF energy harvester circuit. All circuits are designed in 0.18 μm TSMC CMOS technology.

  12. Electron bunch energy and phase feed-forward stabilization system for the Mark V RF-linac free-electron laser

    NASA Astrophysics Data System (ADS)

    Hadmack, M. R.; Jacobson, B. T.; Kowalczyk, J. M. D.; Lienert, B. R.; Madey, J. M. J.; Szarmes, E. B.

    2013-06-01

    An amplitude and phase compensation system has been developed and tested at the University of Hawai`i for the optimization of the RF drive system to the Mark V free-electron laser. Temporal uniformity of the RF drive is essential to the generation of an electron beam suitable for optimal free-electron laser performance and the operation of an inverse Compton scattering x-ray source. The design of the RF measurement and compensation system is described in detail and the results of RF phase compensation are presented. Performance of the free-electron laser was evaluated by comparing the measured effects of phase compensation with the results of a computer simulation. Finally, preliminary results are presented for the effects of amplitude compensation on the performance of the complete system.

  13. Electron bunch energy and phase feed-forward stabilization system for the Mark V RF-linac free-electron laser.

    PubMed

    Hadmack, M R; Jacobson, B T; Kowalczyk, J M D; Lienert, B R; Madey, J M J; Szarmes, E B

    2013-06-01

    An amplitude and phase compensation system has been developed and tested at the University of Hawai'i for the optimization of the RF drive system to the Mark V free-electron laser. Temporal uniformity of the RF drive is essential to the generation of an electron beam suitable for optimal free-electron laser performance and the operation of an inverse Compton scattering x-ray source. The design of the RF measurement and compensation system is described in detail and the results of RF phase compensation are presented. Performance of the free-electron laser was evaluated by comparing the measured effects of phase compensation with the results of a computer simulation. Finally, preliminary results are presented for the effects of amplitude compensation on the performance of the complete system. PMID:23822338

  14. Electron bunch energy and phase feed-forward stabilization system for the Mark V RF-linac free-electron laser

    SciTech Connect

    Hadmack, M. R.; Kowalczyk, J. M. D.; Lienert, B. R.; Madey, J. M. J.; Szarmes, E. B.; Jacobson, B. T.

    2013-06-15

    An amplitude and phase compensation system has been developed and tested at the University of Hawai'i for the optimization of the RF drive system to the Mark V free-electron laser. Temporal uniformity of the RF drive is essential to the generation of an electron beam suitable for optimal free-electron laser performance and the operation of an inverse Compton scattering x-ray source. The design of the RF measurement and compensation system is described in detail and the results of RF phase compensation are presented. Performance of the free-electron laser was evaluated by comparing the measured effects of phase compensation with the results of a computer simulation. Finally, preliminary results are presented for the effects of amplitude compensation on the performance of the complete system.

  15. Nanofabrication using home-made RF plasma coupled chemical vapour deposition system

    NASA Astrophysics Data System (ADS)

    Ong, Si Ci; Ilyas, Usman; Rawat, Rajdeep Singh

    2014-08-01

    Zinc oxide, ZnO, a popular semiconductor material with a wide band gap (3.37 eV) and high binding energy of the exciton (60 meV), has numerous applications such as in optoelectronics, chemical/biological sensors, and drug delivery. This project aims to (i) optimize the operating conditions for growth of ZnO nanostructures using the chemical vapor deposition (CVD) method, and (ii) investigate the effects of coupling radiofrequency (RF) plasma to the CVD method on the quality of ZnO nanostructures. First, ZnO nanowires were synthesized using a home-made reaction setup on gold-coated and non-coated Si (100) substrates at 950 °C. XRD, SEM, EDX, and PL measurements were used for characterizations and it was found that a deposition duration of 10 minutes produced the most well-defined ZnO nanowires. SEM analysis revealed that the nanowires had diameters ranging from 30-100 mm and lengths ranging from 1-4 µm. In addition, PL analysis showed strong UV emission at 380 nm, making it suitable for UV lasing. Next, RF plasma was introduced for 30 minutes. Both remote and in situ RF plasma produced less satisfactory ZnO nanostructures with poorer crystalline structure, surface morphology, and optical properties due to etching effect of energetic ions produced from plasma. However, a reduction in plasma discharge duration to 10 minutes produced thicker and shorter ZnO nanostructures. Based on experimentation conducted, it is insufficient to conclude that RF plasma cannot aid in producing well-defined ZnO nanostructures. It can be deduced that the etching effect of energetic ions outweighed the increased oxygen radical production in RF plasma nanofabrication.

  16. Barrier RF stacking

    SciTech Connect

    Chou, W.; Wildman, D.; Zheng, H.; Takagi, A.; /KEK, Tsukuba

    2004-12-01

    A novel wideband RF system, nicknamed the barrier RF, has been designed, fabricated and installed in the Fermilab Main Injector. The cavity is made of seven Finemet cores, and the modulator made of two bipolar high-voltage fast solid-state switches. The system can deliver {+-}7 kV square pulses at 90 kHz. The main application is to stack two proton batches injected from the Booster and squeeze them into the size of one so that the bunch intensity can be doubled. High intensity beams have been successfully stacked and accelerated to 120 GeV with small losses. The problem of large longitudinal emittance growth is the focus of the present study. An upgraded system with two barrier RF cavities for continuous stacking is under construction. This work is part of the US-Japan collaborative agreement.

  17. Barrier RF Stacking

    SciTech Connect

    Chou, W.; Wildman, D.; Zheng, H.; Takagi, A.

    2005-06-08

    A novel wideband RF system, nicknamed the barrier RF, has been designed, fabricated and installed in the Fermilab Main Injector. The cavity is made of seven Finemet cores, and the modulator made of two bipolar high-voltage fast solid-state switches. The system can deliver {+-}7 kV square pulses at 90 kHz. The main application is to stack two proton batches injected from the Booster and squeeze them into the size of one so that the bunch intensity can be doubled. High intensity beams have been successfully stacked and accelerated to 120 GeV with small losses. The problem of large longitudinal emittance growth is the focus of the present study. An upgraded system with two barrier RF cavities for continuous stacking is under construction. This work is part of the US-Japan collaborative agreement.

  18. Barrier RF Stacking

    NASA Astrophysics Data System (ADS)

    Chou, W.; Wildman, D.; Zheng, H.; Takagi, A.

    2005-06-01

    A novel wideband RF system, nicknamed the barrier RF, has been designed, fabricated and installed in the Fermilab Main Injector. The cavity is made of seven Finemet cores, and the modulator made of two bipolar high-voltage fast solid-state switches. The system can deliver ±7 kV square pulses at 90 kHz. The main application is to stack two proton batches injected from the Booster and squeeze them into the size of one so that the bunch intensity can be doubled. High intensity beams have been successfully stacked and accelerated to 120 GeV with small losses. The problem of large longitudinal emittance growth is the focus of the present study. An upgraded system with two barrier RF cavities for continuous stacking is under construction. This work is part of the US-Japan collaborative agreement.

  19. RESULTS FROM A DEMONSTRATION OF RF-BASED UF6 CYLINDER ACCOUNTING AND TRACKING SYSTEM INSTALLED AT A USEC FACILITY

    SciTech Connect

    Pickett, Chris A; Kovacic, Donald N; Morgan, Jim; Younkin, James R; Carrick, Bernie; Ken, Whittle; Johns, R E

    2008-09-01

    Approved industry-standard cylinders are used globally for storing and transporting uranium hexafluoride (UF{sub 6}) at uranium enrichment plants and processing facilities. To verify that no diversion or undeclared production of nuclear material involving UF{sub 6} cylinders at the facility has occurred, the International Atomic Energy Agency (IAEA) conducts periodic, labor-intensive physical inspections to validate facility records, cylinder identities, and cylinder weights. A reliable cylinder monitoring system that would improve overall inspector effectiveness would be a significant improvement to the current international safeguards inspection regime. Such a system could include real-time unattended monitoring of cylinder movements, situation-specific rules-based event detection algorithms, and the capability to integrate with other types of safeguards technologies. This type of system could provide timely detection of abnormal operational activities that may be used to ensure more appropriate and efficient responses by the IAEA. A system of this type can reduce the reliance on paper records and have the additional benefit of facilitating domestic safeguards at the facilities at which it is installed. A radio-frequency (RF)-based system designed to track uranium hexafluoride (UF{sub 6}) cylinders during processing operations was designed, assembled, and tested at the United States Enrichment Corporation (USEC) facility in Portsmouth, Ohio, to determine the operational feasibility and durability of RF technology. The overall objective of the effort was to validate the robustness of RF technology for potential use as a future international safeguards tool for tracking UF6 cylinders at uranium-processing facilities. The results to date indicate that RF tags represent a feasible technique for tracking UF{sub 6} cylinders in operating facilities. Additional work will be needed to improve the operational robustness of the tags for repeated autoclave processing and to

  20. An rf system using all-solid-state amplifiers for the JAERI FEL

    NASA Astrophysics Data System (ADS)

    Sawamura, M.; Ohkubo, M.; Minehara, E.; Nagai, R.; Takao, M.; Kikuzawa, N.; Sugimoto, M.; Suzuki, Y.; Kawarasaki, Y.; Nagatsuka, K.; Sato, K.; Matsumoto, H.; Kashiwagi, A.

    1993-07-01

    The JAERI FEL linac is energized with four kinds of all-solid-state amplifiers having 5, 1.5, 4, and 50 kW of peak power with a 1-2 ms pulse length. Amplitude and phase stabilities of the 50 kW amplifiers are ˜ 1% and ˜1°, respectively. A feed-forward loop circuit is effective when a feedback loop circuit is not able to stabilize the output of rf power.

  1. Status of RF system for the JAERI energy-recovery linac FEL

    NASA Astrophysics Data System (ADS)

    Sawamura, Masaru; Nagai, Ryoji

    2006-02-01

    The two types of the RF sources are used for the JAERI ERL-FEL. One is an all-solid state amplifier and the other is an inductive output tube (IOT). There are advantages of little failure and wide bandwidth for the all-solid state amplifier, low cost and high efficiency for IOT. The property of low cost with the IOT is suitable for a large machine like an energy recovery linac (ERL).

  2. Performance of multi-aperture grid extraction systems for an ITER-relevant RF-driven negative hydrogen ion source

    NASA Astrophysics Data System (ADS)

    Franzen, P.; Gutser, R.; Fantz, U.; Kraus, W.; Falter, H.; Fröschle, M.; Heinemann, B.; McNeely, P.; Nocentini, R.; Riedl, R.; Stäbler, A.; Wünderlich, D.

    2011-07-01

    The ITER neutral beam system requires a negative hydrogen ion beam of 48 A with an energy of 0.87 MeV, and a negative deuterium beam of 40 A with an energy of 1 MeV. The beam is extracted from a large ion source of dimension 1.9 × 0.9 m2 by an acceleration system consisting of seven grids with 1280 apertures each. Currently, apertures with a diameter of 14 mm in the first grid are foreseen. In 2007, the IPP RF source was chosen as the ITER reference source due to its reduced maintenance compared with arc-driven sources and the successful development at the BATMAN test facility of being equipped with the small IPP prototype RF source ( {\\sim}\\frac{1}{8} of the area of the ITER NBI source). These results, however, were obtained with an extraction system with 8 mm diameter apertures. This paper reports on the comparison of the source performance at BATMAN of an ITER-relevant extraction system equipped with chamfered apertures with a 14 mm diameter and 8 mm diameter aperture extraction system. The most important result is that there is almost no difference in the achieved current density—being consistent with ion trajectory calculations—and the amount of co-extracted electrons. Furthermore, some aspects of the beam optics of both extraction systems are discussed.

  3. Effect of Mixed Glass Former on Ionic Conductivity of Silver Boro Tungstate glass system x[0.75AgI:0.25AgCl]: (1-x) [Ag2O-{B2O3:WO3}

    NASA Astrophysics Data System (ADS)

    Dehariya, Harsha; Kumar, R.; Polu, A. R.

    2012-05-01

    The idea to explore new 'Superionic Electrolytes', "Fast ionic conductors" is due to their tremendous potential applications in solid state electrochemical devices viz. solid state batteries, fuel cells, sensors, super capacitors. Superionic glasses have attracted great deal of attention due to their several advantageous over their crystalline counterparts such as high ionic conductivity, easy preparation, wide selection of compositions, isotropic properties and high stability etc [4-7]. Large numbers of silver ion based glasses have been reported in the literature for the glassy system of AgI:Ag2O: MxOy (MxOy = B2O3, SiO2, P2O5, GeO2, V2O5, As2O5, CrO3, SeO2, MoO3 & TeO3 etc many of them shows high silver ion conductivity [8]. Ion transport behavior of Silver Boro Tungstate glass system x[0.75AgI:0.25AgCl]: (1-x) [Ag2O{B2O3:WO3}], where 0 <= x <= 1 in molar wt% prepared by melt quench technique were reported. The new host [0.75AgI:0.25AgCl] was used as a better alternate in place of conventional host salt AgI. Conductivity measurement were carried out on this glass system as a function of frequency from 50 Hz to 5 MHz, over a temperature range of 27°C to 200°C, for different compositions by Impedance spectroscopy. The composition 0.7[0.75AgI:0.25AgCl]: 0.3[Ag2O{B2O3:WO3}] shows the highest conductivity of the order of σrt ~ 2.76 × 10-2 S/cm, referred to as the Optimum Conducting Composition (OCC). The enhancement in the conductivity has been obtained by mixed former effect. XRD result shows that the system is completely amorphous. Temperature dependence of conductivity of all compositions were studied & reported. Activation energies (Ea) were also evaluated from the slope of .Log(σ) vs 1000/T, Arrhenius plots.

  4. RF transformer

    DOEpatents

    Smith, James L.; Helenberg, Harold W.; Kilsdonk, Dennis J.

    1979-01-01

    There is provided an improved RF transformer having a single-turn secondary of cylindrical shape and a coiled encapsulated primary contained within the secondary. The coil is tapered so that the narrowest separation between the primary and the secondary is at one end of the coil. The encapsulated primary is removable from the secondary so that a variety of different capacity primaries can be utilized with one secondary.

  5. Design of an rf separation system for a proton-rich radioisotope beam produced by using an in-flight fragment separator

    NASA Astrophysics Data System (ADS)

    Kim, Myeongjin; Yun, Chong-Cheol; Kim, Jong-Won; Lee, Jaeyu

    2013-03-01

    An in-flight fragment separator is a device to separate a radioisotope (RI) beam of interest produced by bombarding a thin target with a primary heavy-beam usually of high intensity. The isotope beam separation is done by momentum dispersion of dipole magnets and energy loss in a wedge-shaped degrader. However, this separation method is not sufficient for proton-rich isotope beams because their momenta tend to overlap with the low-momentum tails of more abundant fragments produced with larger cross sections. An additional separation technique, which relies on the velocity difference in the isotope beams, can be used to enhance the purity of the desired isotope beam. A separation system based on an rf-kicker was considered, and its beam line was designed using the TRANSPORT and the COSY INFINITY codes. Trajectories and vertical separations of the RI beams were calculated using the LISE++ code. The background isotope beam can be greatly reduced with the use of the rf separator system, but transmission of the isotope beam may be reduced by the aperture of the rf kicker. The lower rf frequency of the primary beam is an important factor in adopting the rf separator system. The electromagnetic design of the rf-kicker was studied.

  6. RF-CLASS: A Remote-sensing-based Interoperable Web service system for Flood Crop Loss Assessment

    NASA Astrophysics Data System (ADS)

    Di, L.; Yu, G.; Kang, L.

    2014-12-01

    Flood is one of the worst natural disasters in the world. Flooding often causes significant crop loss over large agricultural areas in the United States. Two USDA agencies, the National Agricultural Statistics Service (NASS) and Risk Management Agency (RMA), make decisions on flood statistics, crop insurance policy, and recovery management by collecting, analyzing, reporting, and utilizing flooded crop acreage and crop loss information. NASS has the mandate to report crop loss after all flood events. RMA manages crop insurance policy and uses crop loss information to guide the creation of the crop insurance policy and the aftermath compensation. Many studies have been conducted in the recent years on monitoring floods and assessing the crop loss due to floods with remote sensing and geographic information technologies. The Remote-sensing-based Flood Crop Loss Assessment Service System (RF-CLASS), being developed with NASA and USDA support, aims to significantly improve the post-flood agricultural decision-making supports in USDA by integrating and advancing the recently developed technologies. RF-CLASS will operationally provide information to support USDA decision making activities on collecting and archiving flood acreage and duration, recording annual crop loss due to flood, assessing the crop insurance rating areas, investigating crop policy compliance, and spot checking of crop loss claims. This presentation will discuss the remote sensing and GIS based methods for deriving the needed information to support the decision making, the RF-CLASS cybersystem architecture, the standards and interoperability arrangements in the system, and the current and planned capabilities of the system.

  7. Barrier RF stacking

    SciTech Connect

    Weiren Chou and Akira Takagi

    2003-02-24

    This paper introduces a new method for stacking beams in the longitudinal phase space. It uses RF barriers to confine and compress beams in an accelerator, provided that the machine momentum acceptance is a few times larger than the momentum spread of the injected beam. This is the case for the Fermilab Main Injector. A barrier RF system employing Finemet cores and high-voltage solid-state switches is under construction. The goal is to double the number of protons per cycle on the production target for Run2 and NuMI experiments.

  8. Gas Adsorption Properties of Fluorocarbon Thin Films Prepared Using Three Different Types of RF Magnetron Sputtering Systems

    NASA Astrophysics Data System (ADS)

    Satoru Iwamori,; Norihiko Hasegawa,; Satoshi Yano,; Kazutoshi Noda,

    2010-04-01

    Fluorocarbon thin films were deposited onto a quartz crystal with a poly(tetrafluoroethylene) target using three different types of RF magnetron sputtering systems with strong, weak, and unbalanced magnetic fields. The adsorption properties of these thin films for water, ethanol, acetone, acetaldehyde, toluene, and methyl salicylate were evaluated using the quartz crystal microbalance (QCM) method in order to characterize the surface properties of these thin films. These thin films have low sensitivities to non-polar solvents that contain methyl and aromatic groups, and high sensitivities to polar solvents that contain carbonyl and hydroxyl groups. Chemical structures, especially, polar moieties in these fluorocarbon thin films would affect the gas adsorption properties.

  9. High-temperature metal purification using a compact, portable rf heating and levitation system on the wake shield

    NASA Technical Reports Server (NTRS)

    Hahs, C. A.

    1990-01-01

    The potential use of a compact, battery-operated rf levitator and heating system to purify high-temperature melting materials in space is described. The wake shield now being fabricated for the Space Vacuum Epitaxy Center will provide an Ultra-high vacuum (10(exp -14) Torr hydrogen, 10(exp -14) Torr helium, 10(exp -30) Torr oxygen). The use of the wake shield to purify Nb, Ti, W, Ir, and other metals to a purity level not achievable on earth is described.

  10. Modeling closure of the Pd-Ag system in iron meteorites

    NASA Astrophysics Data System (ADS)

    Van Orman, J.; Matthes, M.; Fischer-Gödde, M.; Krawczynski, M. J.; Kleine, T.

    2015-12-01

    J.A. Van Orman1, M. Matthes2, M. Fischer-Godde2, M.J. Krawczynski3, T. Kleine21 Case Western Reserve University, Cleveland, OH 44106 (james.vanorman@case.edu) 2 Westfalische Wilhelms-Universitat Muenster, 48149 Muenster, Germany 3 Washington University, St. Louis, MO 63130 The short-lived Pd-107/Ag-107 system can provide constraints on the timing of assembly and cooling of iron meteorite parent bodies, but to interpret the dates derived from this system it is necessary to understand the closure conditions. Palladium is strongly enriched in the metal phases, and sulphide (troilite) is the primary sink for radiogenic silver. Closure of the system hence depends primarily on the transfer of Ag-107 from metal to troilite. Because cation diffusion in troilite is extremely rapid, Ag-107 transfer is likely to be controlled by diffusion through the metal. Sugiura and Hoshino (2003) estimated a closure temperature of ~1100 K for the Pd/Ag system in iron meteorites under the assumption that the diffusion rate of Ag in the metal is similar to that of Ni diffusion in taenite. Here we consider the problem in more detail, utilizing constraints on Ag diffusion in taenite and kamacite from the metallurgical literature to numerically model diffusive exchange between metal and troilite with simultaneous radiogenic ingrowth. The process is complicated by exsolution of the metal into bcc kamacite and fcc taenite phases during cooling. We will discuss approaches to the treatment of this issue and their influence on the derived closure temperatures. Sugiura N., Hoshino H. (2003) Meteorit. Planet. Sci. 38, 117-143.

  11. MobileRF: A Robust Device-Free Tracking System Based On a Hybrid Neural Network HMM Classifier

    PubMed Central

    Paul, Anindya S.; Wan, Eric A.; Adenwala, Fatema; Schafermeyer, Erich; Preiser, Nick; Kaye, Jeffrey; Jacobs, Peter G.

    2014-01-01

    We present a device-free indoor tracking system that uses received signal strength (RSS) from radio frequency (RF) transceivers to estimate the location of a person. While many RSS-based tracking systems use a body-worn device or tag, this approach requires no such tag. The approach is based on the key principle that RF signals between wall-mounted transceivers reflect and absorb differently depending on a person’s movement within their home. A hierarchical neural network hidden Markov model (NN-HMM) classifier estimates both movement patterns and stand vs. walk conditions to perform tracking accurately. The algorithm and features used are specifically robust to changes in RSS mean shifts in the environment over time allowing for greater than 90% region level classification accuracy over an extended testing period. In addition to tracking, the system also estimates the number of people in different regions. It is currently being developed to support independent living and long-term monitoring of seniors. PMID:25544964

  12. Analysis of Longitudinal Beam Dynamics Behavior and RF System Operative Limits at High Beam Currents in Storage Rings

    SciTech Connect

    Mastorides, T; Rivetta, C.; Fox, J.D.; Winkle, D.Van; Tytelman, D.; /Dimtel, Redwood City

    2008-07-07

    A dynamics simulation model is used to estimate limits of performance of the Positron-Electron Project (PEP-II). The simulation captures the dynamics and technical limitations of the Low Level Radio Frequency (LLRF) system, the high-power RF components and the low-order mode coupled bunch longitudinal beam dynamics. Simulation results showing the effect of non-linearities on the LLRF loops, and studies of the effectiveness of technical component upgrades are reported, as well as a comparison of these results with PEP-II measurements. These studies have led to the estimation of limits and determining factors in the maximum stored current that the Low Energy Ring/High Energy Ring (LER/HER) can achieve, based on system stability for different RF station configurations and upgrades. In particular, the feasibility of the PEP-II plans to achieve the final goal in luminosity, which required an increase of the beam currents to 4A for LER and 2.2A for HER, is studied. These currents are challenging in part because they would push the longitudinal low-order beam mode stability to the limit, and the klystron forward power past a level of satisfactory margin. An acceptable margin is defined in this paper, which in turn determines the corresponding klystron forward power limitation.

  13. Simplification of millimeter-wave radio-over-fiber system employing heterodyning of uncorrelated optical carriers and self-homodyning of RF signal at the receiver.

    PubMed

    Islam, A H M Razibul; Bakaul, Masuduzzaman; Nirmalathas, Ampalavanapillai; Town, Graham E

    2012-02-27

    A simplified millimeter-wave (mm-wave) radio-over-fiber (RoF) system employing a combination of optical heterodyning in signal generation and radio frequency (RF) self-homodyning in data recovery process is proposed and demonstrated. Three variants of the system are considered in which two independent uncorrelated lasers with a frequency offset equal to the desired mm-wave carrier frequency are used to generate the transmitted signal. Uncorrelated phase noise in the resulting mm-wave signal after photodetection was overcome by using RF self-homodyning in the data recovery process. Theoretical analyses followed by experimental results and simulated characterizations confirm the system's performance. A key advantage of the system is that it avoids the need for high-speed electro-optic and electronic devices operating at the RF carrier frequency at both the central station and base stations.

  14. Nonstoichiometry in inorganic fluorides: I. Nonstoichiometry in MF{sub m}-RF{sub n} (m < n {<=} 4) systems

    SciTech Connect

    Sobolev, B. P.

    2012-05-15

    The manifestation of gross nonstoichiometry in MF{sub m}-RF{sub n} systems (m < n {<=} 4) has been studied. Fluorides of 34 elements, in the systems of which phases of practical interest are formed, are chosen. To search for new phases of complex composition, a program for studying the phase diagrams of the condensed state ({approx}200 systems) has been carried out at the Institute of Crystallography, Russian Academy of Sciences. The main products of high-temperature interactions of the fluorides of elements with different valences (m {ne} n) are grossly nonstoichiometric phases of two structural types: fluorite (CaF{sub 2}) and tysonite (LaF{sub 3}). Systems of fluorides of 27 elements (M{sup 1+} = Na, K; M{sup 2+} = Ca, Sr, Ba, Cd, Pb; R{sup 3+} = Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; R{sup 4+} = Zr, Hf, Th, U) are selected; nonstoichiometric M{sub 1-x}R{sub x}F{sub m(1-x)+nx} phases, which are of greatest practical interest, are formed in these systems. The gross nonstoichiometry in inorganic fluorides is most pronounced in 80 MF{sub 2} - RF{sub 3} systems (M = Ca, Sr, Ba, Cd, Pb; R are rare earth elements). The problems related to the growth of single crystals of nonstoichiometric phases and basic fields of their application as new fluoride multicomponent materials, the properties of which are controlled by the defect structure, are considered.

  15. Diffusion Dynamics of Charged Dust Particles in Capacitively Coupled RF Discharge System

    SciTech Connect

    Chew, W. X.; Muniandy, S. V.; Wong, C. S.; Yap, S. L.; Tan, K. S.

    2011-03-30

    Dusty plasma is loosely defined as electron-ion plasma with additional charged components of micron-sized dust particles. In this study, we developed a particle diagnostic technique based on light scattering and particle tracking velocimetry to investigate the dynamics of micron-sized titanium oxide particles in Argon gas capacitively coupled rf-discharge. The particle trajectories are constructed from sequence of image frames and treated as sample paths of charged Brownian motion. At specific sets of plasma parameters, disordered liquid-like dust particle configuration are observed. Mean-square-displacement of the particle trajectories are determined to characterize the transport dynamics. We showed that the dust particles in disordered liquid phase exhibit anomalous diffusion with different scaling exponents for short and large time scales, indicating the presence of slow and fast modes which can be related to caging effect and dispersive transport, respectively.

  16. A high temperature superconductor tape RF receiver coil for a low field magnetic resonance imaging system

    NASA Astrophysics Data System (ADS)

    Cheng, M. C.; Yan, B. P.; Lee, K. H.; Ma, Q. Y.; Yang, E. S.

    2005-08-01

    High temperature superconductor (HTS) thin films have been applied in making a low loss RF receiver coil for improving magnetic resonance imaging image quality. However, the application of these coils is severely limited by their limited field of view (FOV). Stringent fabrication environment requirements and high cost are further limitations. In this paper, we propose a simpler method for designing and fabricating HTS coils. Using industrial silver alloy sheathed Bi(2-x)PbxSr2Ca2Cu3O10 (Bi-2223) HTS tapes, a five-inch single-turn HTS solenoid coil has been developed, and human wrist images have been acquired with this coil. The HTS tape coil has demonstrated an enhanced FOV over a six-inch YBCO thin film surface coil at 77 K with comparable signal-to-noise ratio.

  17. An RF energy harvester system using UHF micropower CMOS rectifier based on a diode connected CMOS transistor.

    PubMed

    Shokrani, Mohammad Reza; Khoddam, Mojtaba; Hamidon, Mohd Nizar B; Kamsani, Noor Ain; Rokhani, Fakhrul Zaman; Shafie, Suhaidi Bin

    2014-01-01

    This paper presents a new type diode connected MOS transistor to improve CMOS conventional rectifier's performance in RF energy harvester systems for wireless sensor networks in which the circuits are designed in 0.18  μm TSMC CMOS technology. The proposed diode connected MOS transistor uses a new bulk connection which leads to reduction in the threshold voltage and leakage current; therefore, it contributes to increment of the rectifier's output voltage, output current, and efficiency when it is well important in the conventional CMOS rectifiers. The design technique for the rectifiers is explained and a matching network has been proposed to increase the sensitivity of the proposed rectifier. Five-stage rectifier with a matching network is proposed based on the optimization. The simulation results shows 18.2% improvement in the efficiency of the rectifier circuit and increase in sensitivity of RF energy harvester circuit. All circuits are designed in 0.18 μm TSMC CMOS technology. PMID:24782680

  18. AN UPGRADE OF MAGNET-FIELD-DRIVEN TIMING SYSTEMS AT THE AGS.

    SciTech Connect

    TIAN, Y.; OERTER, B.

    2005-10-10

    An upgrade of the main magnet-field-driven timing systems at Brookhaven National Laboratory's Alternating Gradient Synchrotron (AGS) and Booster accelerators will be described in this paper. A novel approach using content addressable memory (CAM) is applied to overcome a weakness in the previous systems, which required a reproducible dwell field for proper operation. Upgraded from a multibus-based system to a VME-based system, the new timing system also proves easier to maintain and to diagnose. Details of the system architecture, as well as its application in other timing systems will be discussed.

  19. Signal Processing for Wireless Communication MIMO System with Nano- Scaled CSDG MOSFET based DP4T RF Switch.

    PubMed

    Srivastava, Viranjay M

    2015-01-01

    In the present technological expansion, the radio frequency integrated circuits in the wireless communication technologies became useful because of the replacement of increasing number of functions, traditional hardware components by modern digital signal processing. The carrier frequencies used for communication systems, now a day, shifted toward the microwave regime. The signal processing for the multiple inputs multiple output wireless communication system using the Metal- Oxide-Semiconductor Field-Effect-Transistor (MOSFET) has been done a lot. In this research the signal processing with help of nano-scaled Cylindrical Surrounding Double Gate (CSDG) MOSFET by means of Double- Pole Four-Throw Radio-Frequency (DP4T RF) switch, in terms of Insertion loss, Isolation, Reverse isolation and Inter modulation have been analyzed. In addition to this a channel model has been presented. Here, we also discussed some patents relevant to the topic. PMID:25986227

  20. Signal Processing for Wireless Communication MIMO System with Nano- Scaled CSDG MOSFET based DP4T RF Switch.

    PubMed

    Srivastava, Viranjay M

    2015-01-01

    In the present technological expansion, the radio frequency integrated circuits in the wireless communication technologies became useful because of the replacement of increasing number of functions, traditional hardware components by modern digital signal processing. The carrier frequencies used for communication systems, now a day, shifted toward the microwave regime. The signal processing for the multiple inputs multiple output wireless communication system using the Metal- Oxide-Semiconductor Field-Effect-Transistor (MOSFET) has been done a lot. In this research the signal processing with help of nano-scaled Cylindrical Surrounding Double Gate (CSDG) MOSFET by means of Double- Pole Four-Throw Radio-Frequency (DP4T RF) switch, in terms of Insertion loss, Isolation, Reverse isolation and Inter modulation have been analyzed. In addition to this a channel model has been presented. Here, we also discussed some patents relevant to the topic.

  1. MICRO-BUNCHING OF THE AGS SLOW EXTRACTED BEAM FOR A RARE KAON DECAY SEARCH.

    SciTech Connect

    GLENN,J.; SIVERTZ,M.; CHIANG,I.; LAZARUS,D.; KOSCIELNIAK,S.

    2001-06-18

    The AGS Slow Extracted Beam (SEB) must be chopped with 250 ps bursts every 40 ns to permit time-of-flight (ToF) measurement of the secondary K{sup 0} beam. Standard techniques to produce this level of bunching would require excessive rf voltage, thus we have developed a ''Micro-Bunching'' technique of extracting the beam as it is forced between empty rf buckets. A specification of the required rf system will be given. Four-dimensional model simulations of particle dynamics for the planned rf and extraction systems will be shown. Simulations of previous tests along with the test measurements are also presented. Measurement of tight bunching requires dedicated instrumentation. The design of a detector system to measure bunch widths and the extinction factor between bunches will be given; considerations include the various particles produced and transported, timing precision and background.

  2. RF-Medisys: a radio frequency identification-based electronic medical record system for improving medical information accessibility and services at point of care.

    PubMed

    Ting, Jacky S L; Tsang, Albert H C; Ip, Andrew W H; Ho, George T S

    2011-01-01

    This paper presents an innovative electronic medical records (EMR) system, RF-MediSys, which can perform medical information sharing and retrieval effectively and which is accessible via a 'smart' medical card. With such a system, medical diagnoses and treatment decisions can be significantly improved when compared with the conventional practice of using paper medical records systems. Furthermore, the entire healthcare delivery process, from registration to the dispensing or administration of medicines, can be visualised holistically to facilitate performance review. To examine the feasibility of implementing RF-MediSys and to determine its usefulness to users of the system, a survey was conducted within a multi-disciplinary medical service organisation that operates a network of medical clinics and paramedical service centres throughout Hong Kong Island, the Kowloon Peninsula and the New Territories. Questionnaires were distributed to 300 system users, including nurses, physicians and patients, to collect feedback on the operation and performance of RF-MediSys in comparison with conventional paper-based medical record systems. The response rate to the survey was 67%. Results showed a medium to high level of user satisfaction with the radiofrequency identification (RFID)-based EMR system. In particular, respondents provided high ratings on both 'user-friendliness' and 'system performance'. Findings of the survey highlight the potential of RF-MediSys as a tool to enhance quality of medical services and patient safety. PMID:21430306

  3. Theory of the electronic states and absorption spectrum of the LiCl:Ag+ impurity system

    NASA Astrophysics Data System (ADS)

    Jackson, Koblar A.; Lin, Chun C.

    1990-01-01

    The impurity absorption spectra of Ag+ and Cu+ impurities in alkali halide hosts show characteristically different features, despite the similar nature of the corresponding free ions. We use the self-interaction-corrected local-spin-density (SIC-LSD) theory to calculate the electronic structure of the ground state (4d) and the 5s and 5p excited states of the LiCl:Ag+ impurity ion. The method of linear combinations of atomic orbitals is used to determine the wave functions and energy levels. By comparing with previous calculations for LiCl:Cu+, we are able to attribute the differences in the d-->s and d-->p transitions in the ultraviolet spectra of these systems to the increased bonding between host crystal and impurity orbitals in LiCl:Ag+, due to the more extensive nature of the Ag+ 4d orbitals. A modification of the earlier SIC-LSD impurity-crystal procedure is introduced to treat the strongly mixed impurity states.

  4. Phase transitions in CuS-Ag2S nanoparticle system

    NASA Astrophysics Data System (ADS)

    Sheela Christy, R.; Thanka Kumaran, J. T.; Bansal, C.; Brightson, M.

    2016-02-01

    (Ag2)xCu1-xS, x = .2, .4, .6 and .8 nanoparticles were synthesized by the solvothermal method. The as-synthesized nanoparticles were characterized by X-ray diffraction to study the crystal structure and size. The surface morphologies of the above samples were studied using scanning electron microscope. As there is continuous shift in the lower wavelength absorption edge of the UV-VIS spectrum of these samples with concentration, (Ag2)xCu1-xS nanoparticles can be tuned to different band gap energies by varying the composition. The D.C. electrical resistance was measured in the temperature range 310-485 K. As Ag2S transforms from monoclinic to bcc at around 450 K, copper sulfide nanoparticles also shows a phase transition at around 470 K, the effects of these two transitions are seen in the resistance measurements and in the UV-VIS spectra of the entire system. The electrical resistance of (Ag2)xCu1-xS nanoparticles rapidly reduces as more and more copper sulfide is added.

  5. Thickness dependence of piezoelectric properties of BiFeO3 films fabricated using rf magnetron sputtering system

    NASA Astrophysics Data System (ADS)

    Aramaki, Masaaki; Kariya, Kento; Yoshimura, Takeshi; Murakami, Shuichi; Fujimura, Norifumi

    2016-10-01

    The piezoelectric property of BiFeO3 films prepared on a (100) LaNiO3/Si(100) substrate using an rf magnetron sputtering system was investigated for their applications in MEMS vibration energy harvesters. The X-ray diffraction profiles indicate that (100)-oriented BiFeO3 films with thicknesses from 450 to 1750 nm were obtained at a deposition temperature of 510 °C. All the films showed well-defined ferroelectric hysteresis loops at room temperature. The thickness dependence of crystallinity and electrical properties indicated that the films have a bottom layer with a high defect density. The e 31,f piezoelectric coefficient and electromechanical coupling factor (k\\text{31,f}2) increase with increasing film thickness and reach -3.2 C/m2 and 3.3%, respectively, at a thickness of 1750 nm, which is considered to be caused by the decrease in defect density.

  6. SiC formation for a solar cell passivation layer using an RF magnetron co-sputtering system

    NASA Astrophysics Data System (ADS)

    Joung, Yeun-Ho; Kang, Hyun Il; Kim, Jung Hyun; Lee, Hae-Seok; Lee, Jaehyung; Choi, Won Seok

    2012-01-01

    In this paper, we describe a method of amorphous silicon carbide film formation for a solar cell passivation layer. The film was deposited on p-type silicon (100) and glass substrates by an RF magnetron co-sputtering system using a Si target and a C target at a room-temperature condition. Several different SiC [Si1-xCx] film compositions were achieved by controlling the Si target power with a fixed C target power at 150 W. Then, structural, optical, and electrical properties of the Si1-xCx films were studied. The structural properties were investigated by transmission electron microscopy and secondary ion mass spectrometry. The optical properties were achieved by UV-visible spectroscopy and ellipsometry. The performance of Si1-xCx passivation was explored by carrier lifetime measurement.

  7. SiC formation for a solar cell passivation layer using an RF magnetron co-sputtering system.

    PubMed

    Joung, Yeun-Ho; Kang, Hyun Il; Kim, Jung Hyun; Lee, Hae-Seok; Lee, Jaehyung; Choi, Won Seok

    2012-01-05

    In this paper, we describe a method of amorphous silicon carbide film formation for a solar cell passivation layer. The film was deposited on p-type silicon (100) and glass substrates by an RF magnetron co-sputtering system using a Si target and a C target at a room-temperature condition. Several different SiC [Si1-xCx] film compositions were achieved by controlling the Si target power with a fixed C target power at 150 W. Then, structural, optical, and electrical properties of the Si1-xCx films were studied. The structural properties were investigated by transmission electron microscopy and secondary ion mass spectrometry. The optical properties were achieved by UV-visible spectroscopy and ellipsometry. The performance of Si1-xCx passivation was explored by carrier lifetime measurement.

  8. Spiral Chip Implantable Radiator and Printed Loop External Receptor for RF Telemetry in Bio-Sensor Systems

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Hall, David G.; Miranda, Felix A.

    2004-01-01

    The paper describes the operation of a patented wireless RF telemetry system, consisting of a bio-MEMS implantable sensor and an external hand held unit, operating over the frequency range of few hundreds of MHz. A MEMS capacitive pressure sensor integrated with a miniature inductor/antenna together constitute the implantable sensor. Signal processing circuits collocated with a printed loop antenna together form the hand held unit, capable of inductively powering and also receiving the telemetry signals from the sensor. The paper in addition, demonstrates a technique to enhance the quality factor and inductance of the inductor in the presence of a lower ground plane and also presents the radiation characteristics of the loop antenna.

  9. Role of silver nanoparticles (AgNPs) on the cardiovascular system.

    PubMed

    Gonzalez, Carmen; Rosas-Hernandez, Hector; Ramirez-Lee, Manuel Alejandro; Salazar-García, Samuel; Ali, Syed F

    2016-03-01

    With the advent of nanotechnology, the use and applications of silver nanoparticles (AgNPs) have increased, both in consumer products as well as in medical devices. However, little is known about the effects of these nanoparticles on human health, more specific in the cardiovascular system, since this system represents an important route of action in terms of distribution, bioaccumulation and bioavailability of the different circulating substances in the bloodstream. A collection of studies have addressed the effects and applications of different kinds of AgNPs (shaped, sized, coated and functionalized) in several components of the cardiovascular system, such as endothelial cells, isolated vessels and organs as well as integrative animal models, trying to identify the underlying mechanisms involved in their actions, to understand their implication in the field of biomedicine. The purpose of the present review is to summarize the most relevant studies to date of AgNPs effects in the cardiovascular system and provide a broader picture of the potential toxic effects and exposure risks, which in turn will allow pointing out the directions of further research as well as new applications of these versatile nanomaterials.

  10. Role of silver nanoparticles (AgNPs) on the cardiovascular system.

    PubMed

    Gonzalez, Carmen; Rosas-Hernandez, Hector; Ramirez-Lee, Manuel Alejandro; Salazar-García, Samuel; Ali, Syed F

    2016-03-01

    With the advent of nanotechnology, the use and applications of silver nanoparticles (AgNPs) have increased, both in consumer products as well as in medical devices. However, little is known about the effects of these nanoparticles on human health, more specific in the cardiovascular system, since this system represents an important route of action in terms of distribution, bioaccumulation and bioavailability of the different circulating substances in the bloodstream. A collection of studies have addressed the effects and applications of different kinds of AgNPs (shaped, sized, coated and functionalized) in several components of the cardiovascular system, such as endothelial cells, isolated vessels and organs as well as integrative animal models, trying to identify the underlying mechanisms involved in their actions, to understand their implication in the field of biomedicine. The purpose of the present review is to summarize the most relevant studies to date of AgNPs effects in the cardiovascular system and provide a broader picture of the potential toxic effects and exposure risks, which in turn will allow pointing out the directions of further research as well as new applications of these versatile nanomaterials. PMID:25543135

  11. RF pulse compression development

    SciTech Connect

    Farkas, Z.D.; Weaver, J.N.

    1987-10-01

    The body of this paper discusses the theory and some rules for designing a multistage Binary Energy Compressor (BEC) including its response to nonstandard phase coding, describes some proof-of-principle experiments with a couple of low power BECs, presents the design parameters for some sample linear collider rf systems that could possibly use a BEC to advantage and outlines in the conclusion some planned R and D efforts. 8 refs., 26 figs., 4 tabs.

  12. Antiproton acceleration in the Fermilab Main Injector using 2.5 MHz (H=28) and 53 MHz (H=588) rf systems

    SciTech Connect

    Vincent Wu et al.

    2003-06-10

    During the Run II era at Fermilab, the Recycler stores antiprotons at 8 GeV and the Main Injector accelerates the antiprotons and the protons from 8 GeV to 150 GeV for Tevatron injection. The Recycler injects antiprotons to the Main Injector in 2.5 MHz rf buckets. This report presents an acceleration scheme for the antiprotons that involves a slow ramp with initial 2.5 MHz acceleration and subsequent fast acceleration with 53 MHz rf system. Beam acceleration and rf manipulation with space charge and beam loading effects are simulated using the longitudinal simulation code ESME. Simulation suggests that one can expect about 15% emittance growth for the entire acceleration cycle with beam loading compensations. Preliminary experimental results with proton beam will also be presented.

  13. Ag/ZnO hybrid systems studied with scanning tunnelling microscopy-based luminescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Pascua, Leandro; Stavale, Fernando; Nilius, Niklas; Freund, Hans-Joachim

    2016-03-01

    Coupled metal/oxide systems are prepared by depositing and embedding Ag nanoparticles into crystalline ZnO films grown on Au(111) supports. The morphology and optical properties of the compounds are investigated by topographic imaging and luminescence spectroscopy performed in a scanning tunnelling microscope (STM). The luminescence of bare ZnO is governed by the band-recombination and a Zn-vacancy related peak. After Ag deposition, two additional maxima are detected that are assigned to the in-plane and out-of-plane plasmon in Ag nanoparticles and have energies below and slightly above the oxide band-gap, respectively. Upon coating the particles with additional ZnO, the out-of-plane plasmon redshifts and loses intensity, indicating strong coupling to the oxide electronic system, while the in-plane mode broadens but remains detectable. The original situation can be restored by gently heating the sample, which drives the silver back to the surface. However, the optical response of pristine ZnO is not recovered even after silver evaporation at high temperature. Small discrepancies are explained with changes in the ZnO defect landscape, e.g., due to silver incorporation. Our experiments demonstrate how energy-transfer processes can be investigated in well-defined metal/oxide systems by means of STM-based spectroscopic techniques.

  14. Wetting and spreading in the Cu-Ag system

    SciTech Connect

    Sharps, Paul R.; Tomsia, Antoni P.; Pask, Joseph A.

    1981-05-01

    In this paper, sessile drop experiments were made in the copper-silver system at the eutectic temperature and 900°C. Wetting, or acute contact angles, were observed for specimens in chemical thermodynamic equilibrium. Spreading occurred when the substrate was not in chemical equilibrium with the liquid. Finally, the interface does not remain aligned with the free surface of the substrate only in the presence of reactions.

  15. Adhesion of human gingival fibroblasts/Streptococcus mitis co-culture on the nanocomposite system Chitlac-nAg.

    PubMed

    Cataldi, Amelia; Gallorini, Marialucia; Di Giulio, Mara; Guarnieri, Simone; Mariggiò, Maria Addolorata; Traini, Tonino; Di Pietro, Roberta; Cellini, Luigina; Marsich, Eleonora; Sancilio, Silvia

    2016-05-01

    Composite materials are increasingly used as dental restoration. In the field of biomaterials, infections remain the main reason of dental devices failure. Silver, in the form of nanoparticles (AgNPs), ions and salt, well known for its antimicrobial properties, is used in several medical applications in order to avoid bacterial infection. To reduce both bacterial adhesion to dental devices and cytotoxicity against eukaryotic cells, we coated BisGMA/TEGDMA methacrylic thermosets with a new material, Chitlac-nAg, formed by stabilized AgNPs with a polyelectrolyte solution containing Chitlac. Here we analyzed the proliferative and adhesive ability of human gingival fibroblasts (HGFs) on BisGMA/TEGDMA thermosets uncoated and coated with AgNPs in a coculture model system with Streptococcus mitis. After 48 h, HGFs well adhered onto both surfaces, while S. mitis cytotoxic response was higher in the presence of AgNPs coated thermosets. After 24 h thermosets coated with Chitlac as well as those coated with Chitlac-nAg exerted a minimal cytotoxic effect on HGFs, while after 48 h LDH release raised up to 20 %. Moreover the presence of S. mitis reduced this release mainly when HGFs adhered to Chitlac-nAg coated thermosets. The reduced secretion of collagen type I was significant in the presence of both surfaces with the co-culture system even more when saliva is added. Integrin β1 localized closely to cell membranes onto Chitlac-nAg thermosets and PKCα translocated into nuclei. These data confirm that Chitlac-nAg have a promising utilization in the field of restorative dentistry exerting their antimicrobial activity due to AgNPs without cytotoxicity for eukaryotic cells.

  16. RF/optical shared aperture for high availability wideband communication RF/FSO links

    SciTech Connect

    Ruggiero, Anthony J; Pao, Hsueh-yuan; Sargis, Paul

    2014-04-29

    An RF/Optical shared aperture is capable of transmitting and receiving optical signals and RF signals simultaneously. This technology enables compact wide bandwidth communications systems with 100% availability in clear air turbulence, rain and fog. The functions of an optical telescope and an RF reflector antenna are combined into a single compact package by installing an RF feed at either of the focal points of a modified Gregorian telescope.

  17. RF/optical shared aperture for high availability wideband communication RF/FSO links

    SciTech Connect

    Ruggiero, Anthony J; Pao, Hsueh-yuan; Sargis, Paul

    2015-03-24

    An RF/Optical shared aperture is capable of transmitting and receiving optical signals and RF signals simultaneously. This technology enables compact wide bandwidth communications systems with 100% availability in clear air turbulence, rain and fog. The functions of an optical telescope and an RF reflector antenna are combined into a single compact package by installing an RF feed at either of the focal points of a modified Gregorian telescope.

  18. RF Gun Optimization Study

    SciTech Connect

    Alicia Hofler; Pavel Evtushenko

    2007-07-03

    Injector gun design is an iterative process where the designer optimizes a few nonlinearly interdependent beam parameters to achieve the required beam quality for a particle accelerator. Few tools exist to automate the optimization process and thoroughly explore the parameter space. The challenging beam requirements of new accelerator applications such as light sources and electron cooling devices drive the development of RF and SRF photo injectors. A genetic algorithm (GA) has been successfully used to optimize DC photo injector designs at Cornell University [1] and Jefferson Lab [2]. We propose to apply GA techniques to the design of RF and SRF gun injectors. In this paper, we report on the initial phase of the study where we model and optimize a system that has been benchmarked with beam measurements and simulation.

  19. AGS SUPER NEUTRINO BEAM FACILITY ACCELERATOR AND TARGET SYSTEM DESIGN (NEUTRINO WORKING GROUP REPORT-II).

    SciTech Connect

    DIWAN,M.; MARCIANO,W.; WENG,W.; RAPARIA,D.

    2003-04-21

    This document describes the design of the accelerator and target systems for the AGS Super Neutrino Beam Facility. Under the direction of the Associate Laboratory Director Tom Kirk, BNL has established a Neutrino Working Group to explore the scientific case and facility requirements for a very long baseline neutrino experiment. Results of a study of the physics merit and detector performance was published in BNL-69395 in October 2002, where it was shown that a wide-band neutrino beam generated by a 1 MW proton beam from the AGS, coupled with a half megaton water Cerenkov detector located deep underground in the former Homestake mine in South Dakota would be able to measure the complete set of neutrino oscillation parameters: (1) precise determination of the oscillation parameters {Delta}m{sub 32}{sup 2} and sin{sup 2} 2{theta}{sub 32}; (2) detection of the oscillation of {nu}{sub {mu}}-{nu}{sub e} and measurement of sin{sup 2} 2{theta}{sub 13}; (3) measurement of {Delta}m{sub 21}{sup 2} sin 2{theta}{sub 12} in a {nu}{sub {mu}} {yields} {nu}{sub e} appearance mode, independent of the value of {theta}{sub 13}; (4) verification of matter enhancement and the sign of {Delta}m{sub 32}{sup 2}; and (5) determination of the CP-violation parameter {delta}{sub CP} in the neutrino sector. This report details the performance requirements and conceptual design of the accelerator and the target systems for the production of a neutrino beam by a 1.0 MW proton beam from the AGS. The major components of this facility include a new 1.2 GeV superconducting linac, ramping the AGS at 2.5 Hz, and the new target station for 1.0 MW beam. It also calls for moderate increase, about 30%, of the AGS intensity per pulse. Special care is taken to account for all sources of proton beam loss plus shielding and collimation of stray beam halo particles to ensure equipment reliability and personal safety. A preliminary cost estimate and schedule for the accelerator upgrade and target system are also

  20. TOPOLOGY FOR A DSP BASED BEAM CONTROL SYSTEM IN THE AGS BOOSTER.

    SciTech Connect

    DELONG,J.BRENNAN,J.M.HAYES,T.LE,T.N.SMITH,K.

    2003-05-12

    The AGS Booster supports beams of ions and protons with a wide range of energies on a pulse-by-pulse modulation basis. This requires an agile beam control system highly integrated with its controls. To implement this system digital techniques in the form of Digital Signal Processors, Direct Digital Synthesizers, digital receivers and high speed Analog to Digital Converters are used. Signals from the beam and cavity pick-ups, as well as measurements of magnetic field strength in the ring dipoles are processed in real time. To facilitate this a multi-processor topology with high bandwidth data links is being designed.

  1. Overview of High Power Vacuum Dry RF Load Designs

    SciTech Connect

    Krasnykh, Anatoly

    2015-08-27

    A specific feature of RF linacs based on the pulsed traveling wave (TW) mode of operation is that only a portion of the RF energy is used for the beam acceleration. The residual RF energy has to be terminated into an RF load. Higher accelerating gradients require higher RF sources and RF loads, which can stably terminate the residual RF power. RF feeders (from the RF source though the accelerating section to the load) are vacuumed to transmit multi-megawatt high power RF. This overview will outline vacuumed RF loads only. A common method to terminate multi-MW RF power is to use circulated water (or other liquid) as an absorbing medium. A solid dielectric interface (a high quality ceramic) is required to separate vacuum and liquid RF absorber mediums. Using such RF load approaches in TW linacs is troubling because there is a fragile ceramic window barrier and a failure could become catastrophic for linac vacuum and RF systems. Traditional loads comprising of a ceramic disk have limited peak and average power handling capability and are therefore not suitable for high gradient TW linacs. This overview will focus on ''vacuum dry'' or ''all-metal'' loads that do not employ any dielectric interface between vacuum and absorber. The first prototype is an original design of RF loads for the Stanford Two-Mile Accelerator.

  2. A systems study of an RF power source for a 1 TeV next linear collider based upon the relativistic-klystron two-beam accelerator

    SciTech Connect

    Yu, S.; Goffeney, N.; Deadrick, F.

    1994-11-01

    A systems study, including physics, engineering and costing, has been conducted to assess the feasibility of a relativistic-klystron two-beam-accelerator (RK-TBA) system as a RF power source candidate for a 1 TeV linear collider. Several key issues associated with a realizable RK-TBA system have been addressed, and corresponding schemes have been developed and examined quantitatively. A point design example has been constructed to present a concrete conceptual design which has acceptable transverse and longitudinal beam stability properties. The overall efficiency of RF production for such a power source is estimated to be 36%, and the cost of the full system is estimated to be less than 1 billion dollars.

  3. A systems study of an RF power source for a 1 TeV next linear collider based upon the relativistic-klystron two-beam accelerator

    SciTech Connect

    Yu, S.; Deadrick, F.; Goffeney, N.; Henestroza, E.; Houck, T.; Li, H.; Peters, C.; Reginato, L.; Sessler, A.; Vanecek, D.; Westenskow, G.

    1995-07-05

    A systems study, including physics, engineering, and costing, has been conducted to assess the feasibility of a relativistic-klystron two-beam-accelerator (RK-TBA) system as a RF power source candidate for a 1 TeV linear collider. Several key issues associated with a realizable RK-TBA system have been addressed, and corresponding schemes have been developed and examined quantitatively. A point design example has been constructed to present a concrete conceptual design which has acceptable transverse and longitudinal beam stability properties. The overall efficiency of RF production for such a power source is estimated to be 36%, and the cost of the full system is estimated to be less than 1 billion dollars. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  4. SYSTEM IDENTIFICATION OF THE LINAC RF SYSTEM USING A WAVELET METHOD AND ITS APPLICATIONS IN THE SNS LLRF CONTROL SYSTEM

    SciTech Connect

    Y. WANG; S. KWON; ET AL

    2001-06-01

    For a pulsed LINAC such as the SNS, an adaptive feed-forward algorithm plays an important role in reducing the repetitive disturbance caused by the pulsed operation conditions. In most modern feed-forward control algorithms, accurate real time system identification is required to make the algorithm more effective. In this paper, an efficient wavelet method is applied to the system identification in which the Haar function is used as the base wavelet. The advantage of this method is that the Fourier transform of the Haar function in the time domain is a sine function in the frequency domain. Thus we can directly obtain the system transfer function in the frequency domain from the coefficients of the time domain system response.

  5. Parametric analysis of RF communications and tracking systems for manned space stations

    NASA Technical Reports Server (NTRS)

    1972-01-01

    System performance, system interface compatibility, and system management and operations are analyzed for external and internal communications provided by the modular space station. Mathematical models are utilized to evaluate performances of the various communication links between the MSS and the tracking and data relay satellites, the shuttle, and the ground stations. Communication control design requirements are determined from overall MSS control design and checkout requirements are developed in a related systems study. Parallel design efforts consider equipment configurations for the external communication assembly baseband and the internal communication assembly to accommodate signal transfer and control. The recommended baseline design considers also interfaces between equipment groups and the critical functional and signal characteristics of these interfaces. The data processing assembly has direct communication circuits to the external communication assembly and the control interface is provided via a digital data bus and a remote acquisition and control unit.

  6. Ultra-fast pulse radiolysis system combined with a laser photocathode RF gun and a femtosecond laser

    NASA Astrophysics Data System (ADS)

    Muroya, Y.; Lin, M.; Watanabe, T.; Wu, G.; Kobayashi, T.; Yoshii, K.; Ueda, T.; Uesaka, M.; Katsumura, Y.

    2002-08-01

    In order to study the early events in radiation physics and chemistry, two kinds of new pulse radiolysis systems with higher time resolution based on pump-and-probe method have been developed at the Nuclear Engineering Research Laboratory, the University of Tokyo. The first one, a few picosecond (2 ps at FWHM) electron beam (pump) from an 18 MeV S-band Linac using a laser photocathode RF gun (BNL/KEK/SHI type: GUN IV) was operated with a femtosecond laser pulse (100 fs at FWHM), which also acted as the analyzing light (probe). The synchronization precision between the pump and the probe was 1.7 ps (rms). In a 1.0 cm sample cell, a time resolution of 12 ps was achieved. The second one, a picosecond (4 ps at FWHM) electron pulse from a 35 MeV S-band Linac employing a conventional thermionic gun with a sub-harmonic buncher, was synchronized with the femtosecond laser pulse, with a synchronization jitter of 2.8 ps (rms). A time resolution of 22 ps was obtained with 2 cm cell. This makes it possible to do the pulse radiolysis experiments in the time range from picosecond to sub-microsecond.

  7. Contact voltage-induced softening of RF microelectromechanical system gold-on-gold contacts at cryogenic temperatures

    SciTech Connect

    Berman, D.; Krim, J.; Walker, M. J.

    2010-08-15

    A series of experiments were performed in vacuum environments to investigate the impact of rf micromechanical system switch contact voltage versus resistance for gold-on-gold contacts at cryogenic temperatures. The purpose of this work was twofold as follows: (1) to examine whether asperity heating models already validated for high temperature contacts were also applicable at cryogenic temperatures and (2) to explore the implications and validity of prior suggestions that contact temperatures between 338 and 373 K are high enough to dissociate adsorbed film and/or push them aside but low enough to prevent asperities from becoming soft and adherent. Measurements on two distinct switch types, fabricated at independent laboratories, were performed in the temperature range 79-293 K and for contact voltages ranging from 0.01 to 0.13 V. Contact resistance values at all temperatures were observed to be lower for higher contact voltages, consistent with the aforementioned asperity heating models, whereby increased contact currents are associated with increased heating and softening effects. In situ removal of adsorbed species by oxygen plasma cleaning resulted in switch adhesive failure. Switches that had not been cleaned meanwhile exhibited distinct reductions in resistance at contact temperatures close to 338 K, consistent with suggestions that films begin to desorb, disassociate, and/or be pushed aside at that temperature.

  8. Tomcat-Projects_RF

    2004-09-15

    Tomcat-Projects_RF is a software package for analyzing sensor data obtained from a database and displaying the results with Java Servlet Pages (JSP). SQL Views into the dataset are tailored for personnel having different roles in monitoring the items in a storage facility. For example, an inspector, a host treaty compliance officer, a system engineer and software developers were the users identified that would need to access data at different levels of detail, The analysis providesmore » a high level status of the storage facility and allows the user to go deeper into the data details if the user desires.« less

  9. Tomcat-Projects_RF

    SciTech Connect

    Warrant, Marilyn M.; Garcia, Rudy J.; Zhang, Pengchu; Arms, Robert M.; Herzer, John A.; Conrad, Gregory N.; Brabson, John M.

    2004-09-15

    Tomcat-Projects_RF is a software package for analyzing sensor data obtained from a database and displaying the results with Java Servlet Pages (JSP). SQL Views into the dataset are tailored for personnel having different roles in monitoring the items in a storage facility. For example, an inspector, a host treaty compliance officer, a system engineer and software developers were the users identified that would need to access data at different levels of detail, The analysis provides a high level status of the storage facility and allows the user to go deeper into the data details if the user desires.

  10. Reliability and throughput issues for optical wireless and RF wireless systems

    NASA Astrophysics Data System (ADS)

    Yu, Meng

    The fast development of wireless communication technologies has two main trends. On one hand, in point-to-point communications, the demand for higher throughput called for the emergence of wireless broadband techniques including optical wireless (OW). One the other hand, wireless networks are becoming pervasive. New application of wireless networks ask for more flexible system infrastructures beyond the point-to-point prototype to achieve better performance. This dissertation investigates two topics on the reliability and throughput issues of new wireless technologies. The first topic is to study the capacity, and practical forward error control strategies for OW systems. We investigate the performance of OW systems under weak atmospheric turbulence. We first investigate the capacity and power allocation for multi-laser and multi-detector systems. Our results show that uniform power allocation is a practically optimal solution for paralleled channels. We also investigate the performance of Reed Solomon (RS) codes and turbo codes for OW systems. We present RS codes as good candidates for OW systems. The second topic targets user cooperation in wireless networks. We evaluate the relative merits of amplify-forward (AF) and decode-forward (DF) in practical scenarios. Both analysis and simulations show that the overall system performance is critically affected by the quality of the inter-user channel. Following this result, we investigate two schemes to improve the overall system performance. We first investigate the impact of the relay location on the overall system performance and determine the optimal location of relay. A best-selective single-relay 1 system is proposed and evaluated. Through the analysis of the average capacity and outage, we show that a small candidate pool of 3 to 5 relays suffices to reap most of the "geometric" gain available to a selective system. Second, we propose a new user cooperation scheme to provide an effective better inter-user channel

  11. Dual Water Systems: Characterization and Performance for Distribution of Reclaimed Water (WaterRF Report 4333)

    EPA Science Inventory

    The research tasks included: an inventory of cases where dual systems have been implemented; formulation of a protocol to identify claimed benefits, costs, and risks; collection of data (quantitative and anecdotal) to assess performance; display of data in the form of performance...

  12. Precise SAR measurements in the near-field of RF antenna systems

    NASA Astrophysics Data System (ADS)

    Hakim, Bandar M.

    Wireless devices must meet specific safety radiation limits, and in order to assess the health affects of such devices, standard procedures are used in which standard phantoms, tissue-equivalent liquids, and miniature electric field probes are used. The accuracy of such measurements depend on the precision in measuring the dielectric properties of the tissue-equivalent liquids and the associated calibrations of the electric-field probes. This thesis describes work on the theoretical modeling and experimental measurement of the complex permittivity of tissue-equivalent liquids, and associated calibration of miniature electric-field probes. The measurement method is based on measurements of the field attenuation factor and power reflection coefficient of a tissue-equivalent sample. A novel method, to the best of the authors knowledge, for determining the dielectric properties and probe calibration factors is described and validated. The measurement system is validated using saline at different concentrations, and measurements of complex permittivity and calibration factors have been made on tissue-equivalent liquids at 900MHz and 1800MHz. Uncertainty analysis have been conducted to study the measurement system sensitivity. Using the same waveguide to measure tissue-equivalent permittivity and calibrate e-field probes eliminates a source of uncertainty associated with using two different measurement systems. The measurement system is used to test GSM cell-phones at 900MHz and 1800MHz for Specific Absorption Rate (SAR) compliance using a Specific Anthropomorphic Mannequin phantom (SAM).

  13. New chalcogenide glasses in the CdTe-AgI-As{sub 2}Te{sub 3} system

    SciTech Connect

    Kassem, M.; Le Coq, D.; Boidin, R.; Bychkov, E.

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Determination of the glass-forming region in the pseudo-ternary CdTe-AgI-As{sub 2}Te{sub 3} system. Black-Right-Pointing-Pointer Characterization of macroscopic properties of the new CdTe-AgI-As{sub 2}Te{sub 3} glasses. Black-Right-Pointing-Pointer Characterization of the total conductivity of CdTe-AgI-As{sub 2}Te{sub 3} glasses. Black-Right-Pointing-Pointer Comparison between the selenide and telluride equivalent systems. -- Abstract: Chalcogenide glasses in the pseudo-ternary CdTe-AgI-As{sub 2}Te{sub 3} system were synthesized and the glass-forming range was determined. The maximum content of CdTe in this glass system was found to be equal to 15 mol.%. The macroscopic characterizations of samples have consisted in Differential Scanning Calorimetry, density, and X-ray diffraction measurements. The cadmium telluride addition does not generate any significant change in the glass transition temperature but the resistance of binary AgI-As{sub 2}Te{sub 3} glasses towards crystallisation is estimated to be decreasing on the base of {Delta}T = T{sub x} - T{sub g} parameter. The total electrical conductivity {sigma} was measured by complex impedance spectroscopy. First, the CdTe additions in the (AgI){sub 0.5}(As{sub 2}Te{sub 3}){sub 0.5} host glass, (CdTe){sub x}(AgI){sub 0.5-x/2}(As{sub 2}Te{sub 3}){sub 0.5-x/2} lead to a conductivity decrease at x {<=} 0.05. Then, the behaviour is reversed at 0.05 {<=} x {<=} 0.15. The obtained results are discussed by comparison with the equivalent selenide system.

  14. Development of the rf-SQUID Based Multiplexing System for the HOLMES Experiment

    NASA Astrophysics Data System (ADS)

    Puiu, A.; Becker, D.; Bennett, D.; Faverzani, M.; Ferri, E.; Fowler, J.; Gard, J.; Hays-Wehle, J.; Hilton, G.; Giachero, A.; Maino, M.; Mates, J.; Nucciotti, A.; Schmidt, D.; Swetz, D.; Ullom, J.; Vale, L.

    2016-07-01

    Measuring the neutrino mass is one of the most compelling issues in particle physics. The European Research Council has funded HOLMES, a new experiment for a direct measurement of neutrino mass that started in 2014. HOLMES will perform a precise measurement of the end point of the Electron Capture decay spectrum of ^{163}Ho in order to extract information on neutrino mass with a sensitivity as low as 0.4 eV. HOLMES, in its final configuration, will deploy a 1000 pixel array of low-temperature microcalorimeters: each calorimeter consists of an absorber, where the Ho atoms will be implanted, coupled to a transition edge sensor thermometer. The read out for an array of 1000 cryogenic detectors is a crucial matter: for HOLMES, a special radio-frequency-based multiplexing system is being developed. In this contribution, we outline the performance and special features of the multiplexing system and readout methods chosen for HOLMES.

  15. RF model of the distribution system as a communication channel, phase 2. Volume 2: Task reports

    NASA Technical Reports Server (NTRS)

    Rustay, R. C.; Gajjar, J. T.; Rankin, R. W.; Wentz, R. C.; Wooding, R.

    1982-01-01

    Based on the established feasibility of predicting, via a model, the propagation of Power Line Frequency on radial type distribution feeders, verification studies comparing model predictions against measurements were undertaken using more complicated feeder circuits and situations. Detailed accounts of the major tasks are presented. These include: (1) verification of model; (2) extension, implementation, and verification of perturbation theory; (3) parameter sensitivity; (4) transformer modeling; and (5) compensation of power distribution systems for enhancement of power line carrier communication reliability.

  16. Design and performance of high voltage power supply with crowbar protection for 3-Φ high power rf amplifier system of cyclotron

    NASA Astrophysics Data System (ADS)

    Thakur, S. K.

    2016-07-01

    The superconducting cyclotron at VECC consists of three rf cavities separated at 120° and each cavity is fed power from an individual rf amplifier, based on a tetrode tube, in the frequency range of 9-27 MHz. All the three tetrode tubes are powered by individual power supplies for their biasing which are fabricated and commissioned with the rf system of the cyclotron. The dc power to the anodes of all three tubes is fed from a high voltage power supply rated at 20 kV dc, 22 A along with suitable interlocks and crowbar protection. The tubes are protected by a single ignitron based crowbar system against an internal arc fault by diverting the stored energy very fast, minimizing the deposited amount of energy at load and allowing the fault to clear. The performance and protective capability of the crowbar system is demonstrated by using wire survivability test. The design criteria of anode power supply along with the crowbar protection system, in-house development, testing and performance is presented in this paper.

  17. Effective photocatalytic disinfection of E. coli K-12 using AgBr-Ag-Bi2WO6 nanojunction system irradiated by visible light: the role of diffusing hydroxyl radicals.

    PubMed

    Zhang, Li-Sha; Wong, Kin-Hang; Yip, Ho-Yin; Hu, Chun; Yu, Jimmy C; Chan, Chiu-Yeung; Wong, Po-Keung

    2010-02-15

    Urgent development of effective and low-cost disinfecting technologies is needed to address the problems caused by an outbreak of harmful microorganisms. In this work, we report an effective photocatalytic disinfection of E. coli K-12 by using a AgBr-Ag-Bi(2)WO(6) nanojunction system as a catalyst under visible light (lambda >or= 400 nm) irradiation. The visible-light-driven (VLD) AgBr-Ag-Bi(2)WO(6) nanojunction could completely inactivate 5 x 10(7) cfu mL(-1) E. coli K-12 within 15 min, which was superior to other VLD photocatalysts such as Bi(2)WO(6) superstructure, Ag-Bi(2)WO(6) and AgBr-Ag-TiO(2) composite. Moreover, the photochemical mechanism of bactericidal action for the AgBr-Ag-Bi(2)WO(6) nanojunction was investigated by using different scavengers. It was found that the diffusing hydroxyl radicals generated both by the oxidative pathway and the reductive pathway play an important role in the photocatalytic disinfection. Moreover, direct contact between the AgBr-Ag-Bi(2)WO(6) nanojunction and bacterial cells was not necessary for the photocatalytic disinfection of E. coli K-12. Finally, the photocatalytic destruction of the bacterial cells was directly observed by TEM images and further confirmed by the determination of potassium ion (K(+)) leakage from the killed bacteria. This work provides a potential effective VLD photocatalyst to disinfect the bacterial cells, even to destruct the biofilm that can provide shelter and substratum for microorganisms and resist to disinfection.

  18. Effective photocatalytic disinfection of E. coli K-12 using AgBr-Ag-Bi2WO6 nanojunction system irradiated by visible light: the role of diffusing hydroxyl radicals.

    PubMed

    Zhang, Li-Sha; Wong, Kin-Hang; Yip, Ho-Yin; Hu, Chun; Yu, Jimmy C; Chan, Chiu-Yeung; Wong, Po-Keung

    2010-02-15

    Urgent development of effective and low-cost disinfecting technologies is needed to address the problems caused by an outbreak of harmful microorganisms. In this work, we report an effective photocatalytic disinfection of E. coli K-12 by using a AgBr-Ag-Bi(2)WO(6) nanojunction system as a catalyst under visible light (lambda >or= 400 nm) irradiation. The visible-light-driven (VLD) AgBr-Ag-Bi(2)WO(6) nanojunction could completely inactivate 5 x 10(7) cfu mL(-1) E. coli K-12 within 15 min, which was superior to other VLD photocatalysts such as Bi(2)WO(6) superstructure, Ag-Bi(2)WO(6) and AgBr-Ag-TiO(2) composite. Moreover, the photochemical mechanism of bactericidal action for the AgBr-Ag-Bi(2)WO(6) nanojunction was investigated by using different scavengers. It was found that the diffusing hydroxyl radicals generated both by the oxidative pathway and the reductive pathway play an important role in the photocatalytic disinfection. Moreover, direct contact between the AgBr-Ag-Bi(2)WO(6) nanojunction and bacterial cells was not necessary for the photocatalytic disinfection of E. coli K-12. Finally, the photocatalytic destruction of the bacterial cells was directly observed by TEM images and further confirmed by the determination of potassium ion (K(+)) leakage from the killed bacteria. This work provides a potential effective VLD photocatalyst to disinfect the bacterial cells, even to destruct the biofilm that can provide shelter and substratum for microorganisms and resist to disinfection. PMID:20085257

  19. Attitude Ground System (AGS) For The Magnetospheric Multi-Scale (MMS) Mission

    NASA Technical Reports Server (NTRS)

    Raymond, Juan C.; Sedlak, Joseph E.; Vint, Babak

    2015-01-01

    The Magnetospheric Multiscale (MMS) mission is a Solar-Terrestrial Probe mission consisting of four identically instrumented spin-stabilized spacecraft flying in an adjustable pyramid-like formation around the Earth. The formation of the MMS spacecraft allows for three-dimensional study of the phenomenon of magnetic reconnection, which is the primary objective of the mission. The MMS spacecraft were launched early on March 13, 2015 GMT. Due to the challenging and very constricted attitude and orbit requirements for performing the science, as well as the need to maintain the spacecraft formation, multiple ground functionalities were designed to support the mission. These functionalities were incorporated into a ground system known as the Attitude Ground System (AGS). Various AGS configurations have been used widely to support a variety of three-axis-stabilized and spin-stabilized spacecraft missions within the NASA Goddard Space Flight Center (GSFC). The original MMS operational concept required the AGS to perform highly accurate predictions of the effects of environmental disturbances on the spacecraft orientation and to plan the attitude maneuvers necessary to stay within the science attitude tolerance. The orbit adjustment requirements for formation control drove the need also to perform calibrations that have never been done before in support of NASA GSFC missions. The MMS mission required support analysts to provide fast and accurately calibrated values of the inertia tensor, center of mass, and accelerometer bias for each MMS spacecraft. During early design of the AGS functionalities, a Kalman filter for estimating the attitude, body rates, center of mass, and accelerometer bias, using only star tracker and accelerometer measurements, was heavily analyzed. A set of six distinct filters was evaluated and considered for estimating the spacecraft attitude and body rates using star tracker data only. Four of the six filters are closely related and were compared

  20. Freeze-dried PVP-Ag+ precursors to novel AgBr/AgCl-Ag hybrid nanocrystals for visible-light-driven photodegradation of organic pollutants

    NASA Astrophysics Data System (ADS)

    Chen, Deliang; Chen, Qianqian; Zhang, Wenjie; Ge, Lianfang; Shao, Gang; Fan, Bingbing; Lu, Hongxia; Zhang, Rui; Yang, Daoyuan; Shao, Guosheng

    2015-04-01

    AgBr/AgCl-Ag nanocrystals with various molar Br-to-Ag ratios (RBr/Ag = 0, 1/3, 1/2, 2/3, 1) and different photoreduction times (0-20 min) were synthesized via stepwise liquid-solid reactions using the freeze-dried PVP-Ag+ hybrid as the Ag source, followed by a photoreduction reaction. The AgBr/AgCl-Ag7.5(1:2) nanocrystals obtained take on a spherical morphology with a particle-size range of 58 ± 15 nm. The photocatalytic performance of AgBr/AgCl-Ag nanocrystals was evaluated by photodegrading organic dyes, 4-chlorophenol and isopropanol under artificial visible light (λ ⩾ 420 nm, 100 mW cm-2). For the decomposition of rhodamine B, the AgBr/AgCl-Ag7.5(1:2) nanocrystals has a photodegradation rate of ∼0.87 min-1, ∼159 times higher than that (∼0.0054 min-1) of TiO2 (P25), whereas the AgCl-Ag and AgBr-Ag nanocrystals have photodegradation rates of 0.35 min-1 and 0.45 min-1, respectively. The efficient separation of photogenerated electron-hole pairs in the ternary system consisting of AgBr, AgCl and Ag species plays a key role in the enhancement of photocatalytic performance.

  1. A New Robust Bandpass Sampling Scheme for Multiple RF Signals in SDR System

    NASA Astrophysics Data System (ADS)

    Chi, Chen; Zhang, Yu; Yang, Zhixing

    Software defined radio (SDR) technology has been widely applied for its powerful universality and flexibility in the past decade. To address the issue of bandpass sampling of multiband signals, a novel and efficient method of finding the minimum valid sampling frequency is proposed. Since there are frequency deviations due to the channel effect and hardware instability in actual systems, we also consider the guard-bands between downconverted signal spectra in determining the minimum sampling frequency. In addition, the case that the spectra within the sampled bandwidth are located in inverse placement can be avoided by our proposed method, which will reduce the complexity of the succeeding digital signal process significantly. Simulation results illustrate that the proper minimum sampling frequency can be determined rapidly and accurately.

  2. R&D ERL: Low level RF

    SciTech Connect

    Smith, K.

    2010-01-15

    A superconducting RF (SRF) Energy Recovery Linac (ERL) is currently under development at the Collider-Accelerator Department (C-AD) at Brookhaven National Laboratory (BNL). The major components from an RF perspective are (a) a 5-cell SRF ERL cavity, (b) an SRF photocathode electron gun, and (c) a drive laser for the photocathode gun. Each of these RF subsystems has its own set of RF performance requirements, as well as common requirements for ensuring correct synchronism between them. A low level RF (LLRF) control system is currently under development, which seeks to leverage both technology and experience gained from the recently commissioned RHIC LLRF system upgrade. This note will review the LLRF system requirements and describe the system to be installed at the ERL.

  3. Liquidus projection of the Ag-Ba-Ge system and melting points of clathrate type-I compounds

    SciTech Connect

    Zeiringer, I.; Grytsiv, A.; Broz, P.

    2012-12-15

    The liquidus and solidus projection has been constructed for the Ag-Ba-Ge system up to 33.3 at% Ba, using electron micro probe analysis (EPMA), X-ray powder diffraction (XRD) and differential thermal analysis (DSC/DTA). Eight different primary crystallization regions were found: (Ge), Ba{sub 8}Ag{sub x}Ge{sub 46-x-y}{open_square}{sub y} ({kappa}{sub I}) ({open_square} is a vacancy), Ba{sub 6}Ag{sub x}Ge{sub 25-x} ({kappa}{sub Ix}), BaGe{sub 2}, Ba(Ag{sub 1-x}Ge{sub x}){sub 2} ({tau}{sub 1}), BaAg{sub 2-x}Ge{sub 2+x} ({tau}{sub 2}) BaAg{sub 5} and (Ag). The ternary invariant reactions have been determined for the region investigated and are the basis for a Schulz-Scheil diagram. The second part of this work provides a comprehensive compilation of melting points of ternary A{sub 8}T{sub x}M{sub 46-x} and quaternary (A=Sr, Ba, Eu; T=Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga; M=Si, Ge, Sn) clathrate type-I compounds and decomposition temperatures of inverse clathrate type-I Ge{sub 38}{l_brace}P,As,Sb{r_brace}{sub 8}{l_brace}Cl,Br,I{r_brace}{sub 8}, Si{sub 46-x}P{sub x}Te{sub y} and tin based compounds. - Graphical Abstract: Partial liquidus projection of the Ag-Ba-Ge system. Highlights: Black-Right-Pointing-Pointer The liquidus and solidus projection has been constructed for the Ag-Ba-Ge system up to 33.33 at% Ba. Black-Right-Pointing-Pointer Eight different primary crystallization fields have been found. Black-Right-Pointing-Pointer All the ternary compounds form congruently from the melt. Black-Right-Pointing-Pointer The ternary invariant reactions have been determined and are the basis for a Schulz-Scheil diagram.

  4. Multiharmonic rf feedforward system for compensation of beam loading and periodic transient effects in magnetic-alloy cavities of a proton synchrotron

    NASA Astrophysics Data System (ADS)

    Tamura, Fumihiko; Ohmori, Chihiro; Yamamoto, Masanobu; Yoshii, Masahito; Schnase, Alexander; Nomura, Masahiro; Toda, Makoto; Shimada, Taihei; Hasegawa, Katsushi; Hara, Keigo

    2013-05-01

    Beam loading compensation is a key for acceleration of a high intensity proton beam in the main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC). Magnetic alloy loaded rf cavities with a Q value of 22 are used to achieve high accelerating voltages without a tuning bias loop. The cavity is driven by a single harmonic (h=9) rf signal while the cavity frequency response also covers the neighbor harmonics (h=8,10). Therefore the wake voltage induced by the high intensity beam consists of the three harmonics, h=8,9,10. The beam loading of neighbor harmonics is the source of periodic transient effects and a possible source of coupled bunch instabilities. In the article, we analyze the wake voltage induced by the high intensity beam. We employ the rf feedforward method to compensate the beam loading of these three harmonics (h=8,9,10). The full-digital multiharmonic feedforward system was developed for the MR. We describe the system architecture and the commissioning methodology of the feedforward patterns. The commissioning of the feedforward system has been performed by using high intensity beams with 1.0×1014 proteins per pulse. The impedance seen by the beam is successfully reduced and the longitudinal oscillations due to the beam loading are reduced. By the beam loading compensation, stable high power beam operation is achieved. We also report the reduction of the momentum loss during the debunching process for the slow extraction by the feedforward.

  5. An Ag based brazing system with a tunable thermal expansion for the use as sealant for solid oxide cells

    NASA Astrophysics Data System (ADS)

    Kiebach, Ragnar; Engelbrecht, Kurt; Grahl-Madsen, Laila; Sieborg, Bertil; Chen, Ming; Hjelm, Johan; Norrman, Kion; Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

    2016-05-01

    An Ag-Al2TiO5 composite braze was developed and successfully tested as seal for solid oxide cells. The thermo-mechanical properties of the Ag-Al2TiO5 system and the chemical compatibility between this composite braze and relevant materials used in stacks were characterized and the leak rates as a function of the operation temperature were measured. The thermal expansion coefficient in the Ag-Al2TiO5 system can be tailored by varying the amount of the ceramic filler. The brazing process can be carried out in air, the joining partners showed a good chemical stability and sufficient low leak rates were demonstrated. Furthermore, the long-term stability of the Ag-Al2TiO5 composite braze was studied under relevant SOFC and SOEC conditions. The stability of brazed Crofer/Ag-Al2TiO5/NiO-YSZ assemblies in reducing atmosphere and in pure oxygen was investigated over 500 h at 850 °C. Additionally, a cell component test was performed to investigate the durability of the Ag-Al2TiO5 seal when exposed to dual atmosphere. The seals performed well over 900 h under electrolysis operation conditions (-0.5 A cm2, 850 °C), and no cell degradation related to the Ag-Al2TiO5 sealing was found, indicating that the developed braze system is applicable for the use in SOFC/SOEC stacks.

  6. Introduction to Latest RF ATE with Low Test Cost Solutions

    NASA Astrophysics Data System (ADS)

    Kimishima, Masayuki

    This paper describes latest RF Automated Test Equipment (RF ATE) technologies that include device under test (DUT) connections, a calibration method, and an RF test module mainly focusing on low cost of test (COT). Most important respect for low COT is how achieve a number of simultaneous measurements and short test time as well as a plain calibration. We realized these respects by a newly proposed calibration method and a drastically downsized RF test module with multiple resources and high throughput. The calibration method is very convenient for RF ATE. Major contribution for downsizing of the RF test module is RF circuit technology in form of RF functional system in package (RF-SIPs), resulting in very attractive test solutions.

  7. Phase modulation in RF tag

    DOEpatents

    Carrender, Curtis Lee; Gilbert, Ronald W.

    2007-02-20

    A radio frequency (RF) communication system employs phase-modulated backscatter signals for RF communication from an RF tag to an interrogator. The interrogator transmits a continuous wave interrogation signal to the RF tag, which based on an information code stored in a memory, phase-modulates the interrogation signal to produce a backscatter response signal that is transmitted back to the interrogator. A phase modulator structure in the RF tag may include a switch coupled between an antenna and a quarter-wavelength stub; and a driver coupled between the memory and a control terminal of the switch. The driver is structured to produce a modulating signal corresponding to the information code, the modulating signal alternately opening and closing the switch to respectively decrease and increase the transmission path taken by the interrogation signal and thereby modulate the phase of the response signal. Alternatively, the phase modulator may include a diode coupled between the antenna and driver. The modulating signal from the driver modulates the capacitance of the diode, which modulates the phase of the response signal reflected by the diode and antenna.

  8. Implementing New Methods of Laser Marking of Items in the Nuclear Material Control and Accountability System at SSC RF-IPPE: An Automated Laser Marking System

    SciTech Connect

    Regoushevsky, V I; Tambovtsev, S D; Dvukhsherstnov, V G; Efimenko, V F; Ilyantsev, A I; Russ III, G P

    2009-05-18

    For over ten years SSC RF-IPPE, together with the US DOE National Laboratories, has been working on implementing automated control and accountability methods for nuclear materials and other items. Initial efforts to use adhesive bar codes or ones printed (painted) onto metal revealed that these methods were inconvenient and lacked durability under operational conditions. For NM disk applications in critical stands, there is the additional requirement that labels not affect the neutron characteristics of the critical assembly. This is particularly true for the many stainless-steel clad disks containing highly enriched uranium (HEU) and plutonium that are used at SSC RF-IPPE for modeling nuclear power reactors. In search of an alternate method for labeling these disks, we tested several technological options, including laser marking and two-dimensional codes. As a result, the method of laser coloring was chosen in combination with Data Matrix ECC200 symbology. To implement laser marking procedures for the HEU disks and meet all the nuclear material (NM) handling standards and rules, IPPE staff, with U.S. technical and financial support, implemented an automated laser marking system; there are also specially developed procedures for NM movements during laser marking. For the laser marking station, a Zenith 10F system by Telesis Technologies (10 watt Ytterbium Fiber Laser and Merlin software) is used. The presentation includes a flowchart for the automated system and a list of specially developed procedures with comments. Among other things, approaches are discussed for human-factor considerations. To date, markings have been applied to numerous steel-clad HEU disks, and the work continues. In the future this method is expected to be applied to other MC&A items.

  9. RF-controlled implantable solid state switch

    NASA Technical Reports Server (NTRS)

    Fryer, T. B.

    1971-01-01

    Miniature, totally implantable, solid state RF-controlled switching circuit for biotelemetry systems consumes zero power in off condition and turns on or off by pulse of RF energy. Switch, the size of small coin, is reducible by integrated circuit techniques.

  10. Selective oxidation of ethane using the Au|YSZ|Ag electrochemical membrane system

    SciTech Connect

    Hamakawa, Satoshi; Sato, Koichi; Hayakawa, Takashi; York, A.P.E.; Tsunoda, Tatsuo; Suzuki, Kunio; Shimizu, Masao; Takehira, Katsuomi

    1997-01-01

    The catalytic conversion of ethane to acetaldehyde on an inert gold electrode has been studied using the electrochemical membrane reactor with yttria-stabilized zirconia (YSZ) solid electrolyte at 475 C. On applying a direct current to the reaction cell, 5% ethane in N{sub 2}, Au|YSZ|Ag, 100% O{sub 2}, acetaldehyde was formed and the formation rate increased linearly with increasing current. Selectivities to acetaldehyde and carbon dioxide were 45 and 55%, respectively. The addition of oxygen to the ethane-mixed gas in the anode space did not affect the acetaldehyde formation. The use of YSZ powder as a fixed bed catalyst under the mixed gas flow of ethane and oxygen at 450 to 600 C resulted in the formation of carbon monoxide, carbon dioxide, and ethene. Even the use of N{sub 2}O instead of oxygen resulted in no formation of acetaldehyde. Hence, it is likely that partial oxidation of ethane to acetaldehyde was carried out by the oxygen species transferred electrochemically through the YSZ which appeared at the gold-YSZ-gas triple-phase boundary. From the results of ethanol oxidation over the Au|YSZ|Ag system, the following mechanism was proposed: ethane is dehydrogenated to an ethyl radical, then converted to ethoxide, and finally to acetaldehyde by the oxygen species transferred through the YSZ.

  11. Measuring the thermodynamic properties of saturated solid solutions in the Ag2Te-Bi-Bi2Te3 system by the electromotive force method

    NASA Astrophysics Data System (ADS)

    Prokhorenko, M. V.; Moroz, M. V.; Demchenko, P. Yu.

    2015-08-01

    The temperature dependence of the electromotive force (EMF) of Ag|AgI|glass Ag2GeS3|D galvanic elements (where Ag, D are galvanic element electrodes, D is equilibrium three-phase alloys in the Ag2Te-Bi-Bi2Te3 system, AgI|glass Ag2GeS3 is a two-layer membrane with purely ionic (Ag+) conductivity) is studied in the range of 490-550 K. Analytical equations are obtained for the temperature dependences of the Gibbs energies of the formation of saturated solid solutions of the Bi14Te6, Bi2Te, BiTe, and Bi2Te phases from elements in the Ag2Te-Bi-Bi2Te3 system. E( T) analytical equations are used to calculate the standardstate thermodynamic functions of saturated solid solutions of the Bi14Te6, Bi2Te, BiTe, and Bi2Te3 phases in the Ag2Te-Bi-Bi2Te3 system.

  12. AgMIP's Transdisciplinary Agricultural Systems Approach to Regional Integrated Assessment of Climate Impacts, Vulnerability, and Adaptation

    NASA Technical Reports Server (NTRS)

    Antle, John M.; Valdivia, Roberto O.; Boote, Kenneth J.; Janssen, Sander; Jones, James W.; Porter, Cheryl H.; Rosenzweig, Cynthia; Ruane, Alexander C.; Thorburn, Peter J.

    2015-01-01

    This chapter describes methods developed by the Agricultural Model Intercomparison and Improvement Project (AgMIP) to implement a transdisciplinary, systems-based approach for regional-scale (local to national) integrated assessment of agricultural systems under future climate, biophysical, and socio-economic conditions. These methods were used by the AgMIP regional research teams in Sub-Saharan Africa and South Asia to implement the analyses reported in their respective chapters of this book. Additional technical details are provided in Appendix 1.The principal goal that motivates AgMIP's regional integrated assessment (RIA) methodology is to provide scientifically rigorous information needed to support improved decision-making by various stakeholders, ranging from local to national and international non-governmental and governmental organizations.

  13. High-power test of a new Bethe-hole directional coupler for the PAL XFEL S-band linac RF system

    NASA Astrophysics Data System (ADS)

    Joo, Youngdo; Park, Yongjung; Heo, Hoon; Hu, Jinyul; Park, Sung-Soo; Kim, Sang-Hee; Hwang, Woonha; Moon, Gun-Young; Lee, Sosung; Lee, Heung-Soo; Noh, Sungju; Oh, Kyoungmin

    2013-11-01

    The directional coupler to be used in the Pohang Accelerator Laboratory X-ray free electron laser (PAL XFEL) under construction since 2011 must satisfy the conditions for operating at a peak power of 400 MW and a repetition rate of 120 Hz. In these operational conditions of the PAL XFEL, the old Bethe-hole directional coupler that was originally designed to be used in the Pohang Light Source linac is more likely to inflict damages on the ceramic window that cause vacuum leaks. Therefore, for the new Bethe-hole directional coupler, the original design has been modified to use a conventional N-type RF vacuum feedthrough for vacuum sealing instead of the ceramic window. The new Bethe-hole directional coupler is designed by using a finite-difference time-domain simulation. We have fabricated a prototype, and the result of a high-power test indicates that the RF performance of the new DC satisfies the specifications of the PAL XFEL S-band Linac RF system.

  14. High-power test of the new 3-dB power splitter for the PAL XFEL S-band LINAC RF system

    NASA Astrophysics Data System (ADS)

    Joo, Youngdo; Park, Yongjung; Heo, Hoon; Hu, Jinyul; Park, Sung-Soo; Kim, Sang-Hee; Hwang, Woonha; Moon, Gun-Young; Lee, Sosung; Lee, Heung-Soo; Noh, Sungju; Oh, Kyoungmin

    2014-04-01

    The 3-dB power splitter to be used in the Pohang Accelerator Laboratory X-ay Free-electron Laser (PAL XFEL), which have been under construction since 2011, must operate at a peak power of 400 MW and a repetition rate of 120 Hz. For these operational conditions of the PAL XFEL, the old 3-dB power splitter that was originally designed to be used in the PLS LINAC will most suffer from RF breakdown. Therefore, for the new 3-dB power splitter, the original design has been modified to reduce the field gradient and the surface current. The new 3-dB power splitter is designed by using a finite-difference time-domain (FDTD) simulation. We have fabricated a prototype, and the result of a high-power test indicates that the RF performance of the new 3-dB power splitter satisfies the specifications of the PAL XFEL S-band LINAC RF system.

  15. RF-to-DC Characteristics of Direct Irradiated On-Chip Gallium Arsenide Schottky Diode and Antenna for Application in Proximity Communication System

    PubMed Central

    Mustafa, Farahiyah; Hashim, Abdul Manaf

    2014-01-01

    We report the RF-to-DC characteristics of the integrated AlGaAs/GaAs Schottky diode and antenna under the direct injection and irradiation condition. The conversion efficiency up to 80% under direct injection of 1 GHz signal to the diode was achieved. It was found that the reduction of series resistance and parallel connection of diode and load tend to lead to the improvement of RF-to-DC conversion efficiency. Under direct irradiation from antenna-to-antenna method, the output voltage of 35 mV was still obtainable for the distance of 8 cm between both antennas in spite of large mismatch in the resonant frequency between the diode and the connected antenna. Higher output voltage in volt range is expected to be achievable for the well-matching condition. The proposed on-chip AlGaAs/GaAs HEMT Schottky diode and antenna seems to be a promising candidate to be used for application in proximity communication system as a wireless low power source as well as a highly sensitive RF detector. PMID:24561400

  16. RF-to-DC characteristics of direct irradiated on-chip gallium arsenide Schottky diode and antenna for application in proximity communication system.

    PubMed

    Mustafa, Farahiyah; Hashim, Abdul Manaf

    2014-02-20

    We report the RF-to-DC characteristics of the integrated AlGaAs/GaAs Schottky diode and antenna under the direct injection and irradiation condition. The conversion efficiency up to 80% under direct injection of 1 GHz signal to the diode was achieved. It was found that the reduction of series resistance and parallel connection of diode and load tend to lead to the improvement of RF-to-DC conversion efficiency. Under direct irradiation from antenna-to-antenna method, the output voltage of 35 mV was still obtainable for the distance of 8 cm between both antennas in spite of large mismatch in the resonant frequency between the diode and the connected antenna. Higher output voltage in volt range is expected to be achievable for the well-matching condition. The proposed on-chip AlGaAs/GaAs HEMT Schottky diode and antenna seems to be a promising candidate to be used for application in proximity communication system as a wireless low power source as well as a highly sensitive RF detector.

  17. Development of an eight-channel NMR system using RF detection coils for measuring spatial distributions of current density and water content in the PEM of a PEFC.

    PubMed

    Ogawa, Kuniyasu; Yokouchi, Yasuo; Haishi, Tomoyuki; Ito, Kohei

    2013-09-01

    The water generation and water transport occurring in a polymer electrolyte fuel cell (PEFC) can be estimated from the current density generated in the PEFC, and the water content in the polymer electrolyte membrane (PEM). In order to measure the spatial distributions and time-dependent changes of current density generated in a PEFC and the water content in a PEM, we have developed an eight-channel nuclear magnetic resonance (NMR) system. To detect a NMR signal from water in a PEM at eight positions, eight small planar RF detection coils of 0.6 mm inside diameter were inserted between the PEM and the gas diffusion layer (GDL) in a PEFC. The local current density generated at the position of the RF detection coil in a PEFC can be calculated from the frequency shift of the obtained NMR signal due to an additional magnetic field induced by the local current density. In addition, the water content in a PEM at the position of the RF detection coil can be calculated by the amplitude of the obtained NMR signal. The time-dependent changes in the spatial distributions were measured at 4 s intervals when the PEFC was operated with supply gas under conditions of fuel gas utilization of 0.67 and relative humidity of the fuel gas of 70%RH. The experimental result showed that the spatial distributions of the local current density and the water content in the PEM within the PEFC both fluctuated with time.

  18. The Structure and Electrical Properties of the Ag2Se + Ga2Se3 + GeSe2 Glass System

    NASA Astrophysics Data System (ADS)

    Marple, Maxwell Adam Thomas

    Silver containing homogeneous chalcogenide glasses in the ternary system Ag2Se-Ga2Se3-GeSe2 (AGGS) are synthesized and their atomic structure-property relationships are investigated. Structural studies are carried out using Raman, 77Se, 71Ga, 69Ga, and 109Ag nuclear magnetic resonance (NMR) spectroscopy. The structure of these glasses consists primarily of a network of corner sharing (Ga/Ge)Se4/2 tetrahedra with a small fraction of homopolar Se-Se bonds. Compositional modification of the atomic structure follows the charge compensated network model developed in the literature for aluminosilicate glasses. Ag2Se acts as a network modifier, forming non-bridging Se in glasses with Ag/Ga >1, while Ga 2Se3 plays the role of a network intermediate similar to Al2O3 in oxide glasses. The network favors the formation of homopolar Ge-Ge bonding in glasses with Ag/Ga <1, to accommodate the Se deficiency brought by the incorporation of Ga2Se3 with Ga being tetrahedrally coordinated to Se. This structural model is consistent with the variation in the glass transition temperatures and molar volume. Electrical Impedance Spectroscopy (EIS) reveals the ionic conductivity of the AGGS glasses to be quite high at ambient temperature, reaching up to 10 --4 S/cm for glasses with the highest Ag content. Increasing Se deficiency with respect to stoichiometry can enhance the conductivity further to ˜3x10--4 S/cm . Transference number measurements using the electromotive force (EMF) method as well as variable temperature 109Ag NMR line shape studies indicate that the conductivity is predominantly ionic in nature and results from fast hopping dynamics of Ag ions. The high ionic conductivity can be related to a heavily modified structural network that results in a potential energy landscape with many suitable hopping sites for the Ag ions. These structural characteristics and electrical properties of the glasses in the AGGS system may guide in the development of next generation fast ion

  19. AgRP Neurons Control Systemic Insulin Sensitivity via Myostatin Expression in Brown Adipose Tissue.

    PubMed

    Steculorum, Sophie M; Ruud, Johan; Karakasilioti, Ismene; Backes, Heiko; Engström Ruud, Linda; Timper, Katharina; Hess, Martin E; Tsaousidou, Eva; Mauer, Jan; Vogt, Merly C; Paeger, Lars; Bremser, Stephan; Klein, Andreas C; Morgan, Donald A; Frommolt, Peter; Brinkkötter, Paul T; Hammerschmidt, Philipp; Benzing, Thomas; Rahmouni, Kamal; Wunderlich, F Thomas; Kloppenburg, Peter; Brüning, Jens C

    2016-03-24

    Activation of Agouti-related peptide (AgRP) neurons potently promotes feeding, and chronically altering their activity also affects peripheral glucose homeostasis. We demonstrate that acute activation of AgRP neurons causes insulin resistance through impairment of insulin-stimulated glucose uptake into brown adipose tissue (BAT). AgRP neuron activation acutely reprograms gene expression in BAT toward a myogenic signature, including increased expression of myostatin. Interference with myostatin activity improves insulin sensitivity that was impaired by AgRP neurons activation. Optogenetic circuitry mapping reveals that feeding and insulin sensitivity are controlled by both distinct and overlapping projections. Stimulation of AgRP → LHA projections impairs insulin sensitivity and promotes feeding while activation of AgRP → anterior bed nucleus of the stria terminalis (aBNST)vl projections, distinct from AgRP → aBNSTdm projections controlling feeding, mediate the effect of AgRP neuron activation on BAT-myostatin expression and insulin sensitivity. Collectively, our results suggest that AgRP neurons in mice induce not only eating, but also insulin resistance by stimulating expression of muscle-related genes in BAT, revealing a mechanism by which these neurons rapidly coordinate hunger states with glucose homeostasis. PMID:27015310

  20. Suppression of SRS induced crosstalk in RF-video overlay TWDM-PON system using dicode coding.

    PubMed

    Li, Jun; Bi, Meihua; He, Hao; Hu, Weisheng

    2014-09-01

    In this paper, we investigate the nonlinear Raman crosstalk in RF-video overlay time and wavelength division multiplexed passive optical network (TWDM-PON), and propose a novel spectrum-reshaping method based on dicode coding to mitigate this crosstalk. The dicode coding features ultra-low power spectral density in the low frequency region, which can reduce the nonlinear Raman crosstalk on the RF-video signal effectively. Experimental results show that, compared with traditional non-return-to-zero on-off keying (NRZ-OOK) signals, the crosstalk on RF-video signal can be reduced by 10 ~14 dB when the launch power per TWDM-PON channel varies from 10-dBm to 15-dBm. The transmission of 10-Gb/s dicode signal over 20-km standard single mode fiber (SSMF) is also demonstrated with the receiver sensitivity of -31 dBm at bit error ratio (BER) of 3.8e-3.

  1. Phase relationships and stability of the {mu}- and {zeta}-phases in the Ag-Al-X (X=Zn, Ga, Ge) systems

    SciTech Connect

    Paruchuri, M.R.; Massalaski, T.B.

    1993-09-01

    Details of phase relationships in three ternary systems, Ag-Al-X (X=Zn, Ga, Ge) near the Ag-rich corner at 400C are presented. Metallography, X-ray diffraction, scanning electron microscopy and X-ray spectroscopy have been used to establish the respective isothermal sections at 400C. In each case, the {mu}-phase and the {zeta}-phase of the Ag-Al binary system extend into the ternary system and terminate at a three-phase region involving the Ag-rich primary solid solution ({alpha}{sub 1}-phase) in the Ag-Al-Zn and Ag-Al-Ga systems, and the Ge-rich primary solid solution ({alpha}{sub 2}-phase) in the Ag-Al-Ge ternary system. The stability ranges of the {mu} and {zeta}-phases follow approximately constant electron concentration lines. The solid solubilities of Zn, Ga and Ge in the {mu}-phase are relatively small, compared with those in the {zeta}-phase (up to 18 at. %). No ternary phase appears to exist in the Ag-rich portions studied in the three ternary systems.

  2. Electrical characterization of rf plasmas

    SciTech Connect

    Miller, P.A.

    1991-08-01

    Radio-frequency (rf) electrical sources are commonly used to generate plasmas for processing of industrial materials and for related experimental work. Published descriptions of such plasmas usually include generator-power measurements, and occasionally include plasma dc-bias measurements. One or both of these quantitites are also used in industrial feedback ccontrol systems for setpoint regulation. Recent work at Sandia an elsewhere with an experimental rf discharge device (the GEC RF Reference Cell'') has shown that power and dc-bias levels are often insufficient information for specifying the state of the plasma. The plasma can have nonlinear electrical characteristics that cause harmonic generation, and the harmonic levels can depend sensitively on the impedance of the external circuitry at harmonic frequencies. Even though the harmonics may be low in amplitude, they can be directly related to large changes in plasma power and to changes in optical emission from the plasma. Consequently, in order for a worker to truly master the plasma-generation process, it is necessary to understand, measure, and control electrical characteristics of the plamsa. In this paper we describe technique that have been developed from work with the Reference Cell for making electrical measurements on rf plasmas, and we describe surprising observations of harmonic behavior. 10 refs., 4 figs.

  3. Estimate of radiation damage to low-level electronics of the RF system in the LHC cavities arising from beam gas collisions.

    PubMed

    Butterworth, A; Ferrari, A; Tsoulou, E; Vlachoudis, V; Wijnands, T

    2005-01-01

    Monte Carlo simulations have been performed to estimate the radiation damage induced by high-energy hadrons in the digital electronics of the RF low-level systems in the LHC cavities. High-energy hadrons are generated when the proton beams interact with the residual gas. The contributions from various elements-vacuum chambers, cryogenic cavities, wideband pickups and cryomodule beam tubes-have been considered individually, with each contribution depending on the gas composition and density. The probability of displacement damage and single event effects (mainly single event upsets) is derived for the LHC start-up conditions.

  4. Novel step-tunable wavelength-swept optical system based on a SSB modulator driven by a RF generator for fiber sensing networks

    NASA Astrophysics Data System (ADS)

    Yang, Tianxin; Qiu, Changren; Wang, Changle; Wang, Zhaoying; Ge, Chunfeng; Sang, Mei

    2012-03-01

    High resolution wavelength-tunable lasers are essential to sensing applications. For sensing applications, high resolution is needed to improve the spatial resolution and/or measurement accuracy, and fast tuning (sweeping) is required to enhance the measurement speed for dynamic sensing. However the demand of high resolution conflicts with the requirement of fast continuous wavelength tuning. The solution to this issue is tuning the wavelength of the output in a quasi-continuous way in which the length of each step is dependent on the frequency of a RF generator which is used to drive a single-sideband (SSB) modulator in the wavelength-swept optical system. In this paper, a principle of the step-tunable wavelength-swept optical system is proposed and demonstrated. The two optical features of narrow bandwidth and fairly high optical output power make the system unique for improving the accuracy of the measurement of the center-wavelength of a fiber Bragg grating (FBG) sensor. In addition, changing the tuning-step by adjusting the frequency of a RF generator electrically is user-friendly compared to the conventional wavelength swept systems by tuning optical elements mechanically.

  5. The AgroEcoSystem (AgES) response-function model simulates layered soil water dynamics in semi-arid Colorado: sensitivity and calibration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simulation of vertical soil hydrology is a critical component of simulating even more complex soil water dynamics in space and time, including land-atmosphere and subsurface interactions. The AgroEcoSystem (AgES) model is defined here as a single land unit implementation of the full AgES-W (Watershe...

  6. A component-based, integrated spatially distributed hydrologic/water quality model: AgroEcoSystem-Watershed (AgES-W) overview and application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    AgroEcoSystem-Watershed (AgES-W) is a modular, Java-based spatially distributed model which implements hydrologic/water quality simulation components. The AgES-W model was previously evaluated for streamflow and recently has been enhanced with the addition of nitrogen (N) and sediment modeling compo...

  7. Characterization of the (Ag,Cu)(In,Ga)Se2 thin film alloy system for solar cells

    NASA Astrophysics Data System (ADS)

    Boyle, Jonathan

    Energy is the underlying factor to human economic activity, and more energy is projected to be needed in the near future and photovoltaics provide a means to supply that energy. Results presented in this dissertation detail material properties of the (Ag,Cu)(In,Ga)Se2 thin film alloy system for use as a solar cell material. Structural and optical properties were determined via X-ray diffraction and UV/Vis/NIR spectrophotometry, respectively. Structural data was analyzed using JADE 2010 software and optical data was analyzed via two different methods. Results of Ag substitution into Cu(In,Ga)Se2 alloy were reconciled with the Jaffe-Wei-Zunger (JWZ) theoretical model, which relates structural and chemical properties of Cu-based ternary chalcopyrite alloys to their optical properties. Dominant phase of the alloy system was identified as chalcopyrite I-42d, Space group 122, with minor secondary phases and order defect phases. No chalcopyrite-chalcopyrite miscibility gap was present in the alloy compositional space, counter to prior literature on bulk polycrystalline materials and thermodynamic calculations performed here, indicating that Ag was successfully substituted into the chalcopyrite lattice. Lattice constant results were consistent with JWZ model, where a O lattice constant closely follows Vegard's rule, cO lattice constant changes at different rates than aO does with composition, and anion displacement is affected by cation radii. Optical results showed bandgap widening with Ag and Ga substitution across the full compositional space, with bowing parameters shown overall to be invariant with cation substitution, counter to expectations. (Ag+Cu)/(In+Ga) ratio effect on bandgap for a limited set of samples is consistent with p-d hybridization effects from JWZ model.

  8. Matching network for RF plasma source

    SciTech Connect

    Pickard, Daniel S.; Leung, Ka-Ngo

    2007-11-20

    A compact matching network couples an RF power supply to an RF antenna in a plasma generator. The simple and compact impedance matching network matches the plasma load to the impedance of a coaxial transmission line and the output impedance of an RF amplifier at radio frequencies. The matching network is formed of a resonantly tuned circuit formed of a variable capacitor and an inductor in a series resonance configuration, and a ferrite core transformer coupled to the resonantly tuned circuit. This matching network is compact enough to fit in existing compact focused ion beam systems.

  9. CRFR1 in AgRP Neurons Modulates Sympathetic Nervous System Activity to Adapt to Cold Stress and Fasting.

    PubMed

    Kuperman, Yael; Weiss, Meira; Dine, Julien; Staikin, Katy; Golani, Ofra; Ramot, Assaf; Nahum, Tali; Kühne, Claudia; Shemesh, Yair; Wurst, Wolfgang; Harmelin, Alon; Deussing, Jan M; Eder, Matthias; Chen, Alon

    2016-06-14

    Signaling by the corticotropin-releasing factor receptor type 1 (CRFR1) plays an important role in mediating the autonomic response to stressful challenges. Multiple hypothalamic nuclei regulate sympathetic outflow. Although CRFR1 is highly expressed in the arcuate nucleus (Arc) of the hypothalamus, the identity of these neurons and the role of CRFR1 here are presently unknown. Our studies show that nearly half of Arc-CRFR1 neurons coexpress agouti-related peptide (AgRP), half of which originate from POMC precursors. Arc-CRFR1 neurons are innervated by CRF neurons in the hypothalamic paraventricular nucleus, and CRF application decreases AgRP(+)CRFR1(+) neurons' excitability. Despite similar anatomy in both sexes, only female mice selectively lacking CRFR1 in AgRP neurons showed a maladaptive thermogenic response to cold and reduced hepatic glucose production during fasting. Thus, CRFR1, in a subset of AgRP neurons, plays a regulatory role that enables appropriate sympathetic nervous system activation and consequently protects the organism from hypothermia and hypoglycemia. PMID:27211900

  10. Irrigated and non-irrigated radiofrequency ablation systems and ways of non-irrigated RF systems development

    NASA Astrophysics Data System (ADS)

    Evtushenko, A. V.; Evtushenko, V. V.; Bykov, A. N.; Sergeev, V. S.; Syryamkin, V. I.; Kistenev, Yu. V.; Anfinogenova, Ya. D.; Smyshlyaev, K. A.; Kurlov, I. O.

    2015-11-01

    Improving of radiofrequency ablation systems for the myocardium is one of the fundamental problems of cardiac surgery. We used pig left ventricular myocardium as a working model. Mean thickness of the left ventricular wall was 10.1 ± 5.6 mm. The studies were performed on 10 hearts. The mean weight of hearts was 294.7 ± 21g. Research is being done on the electrophysical bench in 2 stages. In the first stage the hearts were placed on the electrophysical bench and heated to 36.6°C. In the second stage heart cooled to 20°C. The monopolar radiofrequency exposure was processing on the myocardium by two types of electrodes: spherical irrigated electrode and non-irrigated penetrating one within 20 seconds. The electrical resistance of the myocardium was measured at different temperatures before and after exposure. This paper shows that the decrease in ambient temperature combined with using of new penetrating electrodes for radiofrequency ablation gives better results than using of irrigated and non-irrigated systems. This method allows significantly reduce time exposure for a maximum depth of destruction in the myocardium.

  11. Spectroscopy of microcrystals in the CuI-AgI system

    SciTech Connect

    Voll, V.A.; Barmasov, A.V.; Struts, A.V.

    1994-06-01

    Using comparative analysis of the absorption and luminescence spectra of samples with different compositions, we studied the effect of the preparation procedure on the structure of composite CuI-AgI microcrystals formed in the gelatin matrix. The resonance character of excitation and its localization at the substrate/epitax interface were established. The most probable composition of the thermally stable photolytic centers as a function of the relative content of Cu and Ag was discussed.

  12. Processing and evaluation of the AGS Booster ultra-high vaccum system

    SciTech Connect

    Hseuh, H.C.; Mapes, M.; Schnitzenbaumer, P.; Shen, B.; Sikora, R.; Stattel, P.

    1991-01-01

    The AGS Booster is a synchrotron for the acceleration of both protons and heavy ions. To minimize the beam loss due to charge exchange of the partially stripped, low {Beta} very heavy ions with the residual gas molecules, pressure of low 10{sup {minus}11} Torr is required for the 200 m booster ring. To achieve this ultra high vacuum, chemical cleaning, vacuum furnace degassing and insitu bake were employed for all chambers and beam components. Using these procedures, vacuums of low 10{sup {minus}11} Torr have been routinely achieved during the testing of individual half cells and beam components, and during the commissioning of the vacuum sectors. In this paper, the design and layout of chambers, flanges and bakeout hardware is briefly described. The vacuum processing of different components and the results of bakeout and evaluation are summarized. The experience gained during the construction and commissioning of this ultra-high vacuum system is also given. 3 refs., 3 figs., 1 tab.

  13. Si-based RF MEMS components.

    SciTech Connect

    Stevens, James E.; Nordquist, Christopher Daniel; Baker, Michael Sean; Fleming, James Grant; Stewart, Harold D.; Dyck, Christopher William

    2005-01-01

    Radio frequency microelectromechanical systems (RF MEMS) are an enabling technology for next-generation communications and radar systems in both military and commercial sectors. RF MEMS-based reconfigurable circuits outperform solid-state circuits in terms of insertion loss, linearity, and static power consumption and are advantageous in applications where high signal power and nanosecond switching speeds are not required. We have demonstrated a number of RF MEMS switches on high-resistivity silicon (high-R Si) that were fabricated by leveraging the volume manufacturing processes available in the Microelectronics Development Laboratory (MDL), a Class-1, radiation-hardened CMOS manufacturing facility. We describe novel tungsten and aluminum-based processes, and present results of switches developed in each of these processes. Series and shunt ohmic switches and shunt capacitive switches were successfully demonstrated. The implications of fabricating on high-R Si and suggested future directions for developing low-loss RF MEMS-based circuits are also discussed.

  14. Prototype rf cavity for the HISTRAP accelerator

    SciTech Connect

    Mosko, S.W.; Dowling, D.T.; Olsen, D.K.

    1989-01-01

    HISTRAP, a proposed synchrotron-cooling-storage ring designed to both accelerate and decelerate very highly charged very heavy ions for atomic physics research, requires an rf accelerating system to provide /+-/2.5 kV of peak accelerating voltage per turn while tuning through a 13.5:1 frequency range in a fraction of a second. A prototype half-wave, single gap rf cavity with biased ferrite tuning was built and tested over a continuous tuning range of 200 kHz through 2.7 MHz. Initial test results establish the feasibility of using ferrite tuning at the required rf power levels. The resonant system is located entirely outside of the accelerator's 15cm ID beam line vacuum enclosure except for a single rf window which serves as an accelerating gap. Physical separation of the cavity and the beam line permits in situ vacuum baking of the beam line at 300/degree/C.

  15. Rheumatoid factor (RF)

    MedlinePlus

    ... infections Leukemia , multiple myeloma , and other cancers Chronic lung disease Chronic liver disease In some cases, people who are healthy and have no other medical problem will have a higher-than-normal RF level.

  16. Effects of TiO2 coating dosage and operational parameters on a TiO2/Ag photocatalysis system for decolorizing Procion red MX-5B.

    PubMed

    Lin, Yu-Chih; Lee, Ho-Shan

    2010-07-15

    In this study, titanium dioxide (TiO(2)) powder was coated onto the surface of a dendritic silver (Ag) carrier to synthesize TiO(2)/Ag for decolorizing Procion red MX-5B (MX-5B), and related operation factors were also studied. The results showed that even without ultraviolet-A (UVA) irradiation, the Ag carrier from the TiO(2)/Ag catalyst had oxidizing ability, which could effectively degrade MX-5B color, but TiO(2) was ineffective. In addition, TiO(2) from TiO(2)/Ag demonstrated photocatalysis performance when irradiated, and the Ag carrier further showed an electron-scavenging ability to mitigate electron-hole pair recombination, which can improve the photocatalytic efficacy. With the oxidization and electron-scavenging ability of Ag and the photocatalysis ability of TiO(2), TiO(2)/Ag can decolor MX-5B more efficiently than TiO(2). The heavier Ag carrier also improves the solid-liquid separation of nano-TiO(2), making TiO(2)/Ag more suitable for application in slurry systems of photocatalytic water treatment. When the TiO(2)/Ag coating ratio was 50% by weight, there was a sufficient amount of TiO(2) on Ag's surface with a good distribution, and it exhibited a good photocatalysis decolorizing effect. In a study of how operational factors impact the decolorizing of MX-5B in the TiO(2)/Ag photocatalysis system with UVA irradiation (UVA-TiO(2)/Ag), the decolorization efficiency was optimal when the solution was maintained at pH 6.35. The addition of 0.01 M hydrogen peroxide (H(2)O(2)) aided the photocatalysis decolorization efficiency, although excessive H(2)O(2) reacted with hydroxyl free radicals and decreased the active groups in the system, thereby reducing the photocatalysis activity. An operating temperature of 40 degrees C was conducive to MX-5B decolorization, which was better than operating at room temperature.

  17. CT-guided Bipolar and Multipolar Radiofrequency Ablation (RF Ablation) of Renal Cell Carcinoma: Specific Technical Aspects and Clinical Results

    SciTech Connect

    Sommer, C. M.; Lemm, G.; Hohenstein, E.; Bellemann, N.; Stampfl, U.; Goezen, A. S.; Rassweiler, J.; Kauczor, H. U.; Radeleff, B. A.; Pereira, P. L.

    2013-06-15

    Purpose. This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. Methods. We included 22 consecutive patients (3 women; age 74.2 {+-} 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 {+-} 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. Results. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 {+-} 13.6 min and 43.7 {+-} 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 {+-} 8.8 months, local recurrence-free survival was 14.4 {+-} 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 {+-} 16.6 ml/min/1.73 m{sup 2} before RF ablation vs. 47.2 {+-} 11.9 ml/min/1.73 m{sup 2} after RF ablation; not significant). Conclusions. CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

  18. Rf power sources

    SciTech Connect

    Allen, M.A.

    1988-05-01

    This paper covers RF power sources for accelerator applications. The approach has been with particular customers in mind. These customers are high energy physicists who use accelerators as experimental tools in the study of the nucleus of the atom, and synchrotron light sources derived from electron or positron storage rings. This paper is confined to electron-positron linear accelerators since the RF sources have always defined what is possible to achieve with these accelerators. 11 refs., 13 figs.

  19. Microbunching and RF Compression

    SciTech Connect

    Venturini, M.; Migliorati, M.; Ronsivalle, C.; Ferrario, M.; Vaccarezza, C.

    2010-05-23

    Velocity bunching (or RF compression) represents a promising technique complementary to magnetic compression to achieve the high peak current required in the linac drivers for FELs. Here we report on recent progress aimed at characterizing the RF compression from the point of view of the microbunching instability. We emphasize the development of a linear theory for the gain function of the instability and its validation against macroparticle simulations that represents a useful tool in the evaluation of the compression schemes for FEL sources.

  20. Technology development of RF MEMS switches on printed circuit boards

    NASA Astrophysics Data System (ADS)

    Chang, Hung-Pin

    Today, some engineers have shifted their focus on the micro-electro-mechanical system (MEMS) to pursue better technological advancements. Recent development in RF MEMS technologies have lead to superior switch characteristics, i.e., very low insertion loss, very low power requirements, and high isolation comparing to the conventional semiconductor devices. This success has promised the potential of MEMS to revolutionize RF and microwave system implementation for the next generation of communication applications. However, RF MEMS switches integrated monolithically with various RF functional components on the same substrate to create multifunctional and reconfigurable complete communication systems remains to be a challenge research topic due to the concerns of the high cost of packaging process and the high cost of RF matching requirements in module board implementation. Furthermore, the fabrication of most RF MEMS switches requires thickness control and surface planarization of wide metal lines prior to deposition of a metal membrane bridge, which poses a major challenge to manufacturability. To ease the fabrication of RF MEMS switches and to facilitate their integration with other RF components such as antennas, phase delay lines, tunable filters, it is imperative to develop a manufacturable RF MEMS switch technology on a common substrate housing all essential RF components. Development of a novel RF MEMS technology to build a RF MEMS switch and provide a system-level packaging on microwave laminated printed circuit boards (PCBs) are proposed in this dissertation. Two key processes, high-density inductively coupled plasma chemical vapor deposition (HDICP CVD) for low temperature dielectric deposition, and compressive molding planarization (COMP) for the temporary sacrificial polymer planarization have been developed for fabricating RF MEMS switches on PCBs. Several membrane-type capacitive switches have been fabricated showing excellent RF performance and dynamic

  1. Fast beam stacking using rf barriers

    SciTech Connect

    Chou, W.; Capista, D.; Griffin, J.; Ng, K.-Y.; Wildman, D.; /Fermilab

    2007-06-01

    Two barrier RF systems were fabricated, tested and installed in the Fermilab Main Injector. Each can provide 8 kV rectangular pulses (the RF barriers) at 90 kHz. When a stationary barrier is combined with a moving barrier, injected beams from the Booster can be continuously deflected, folded and stacked in the Main Injector, which leads to doubling of the beam intensity. This paper gives a report on the beam experiment using this novel technology.

  2. A no-load RF calorimeter

    NASA Technical Reports Server (NTRS)

    Chernoff, R. C.

    1975-01-01

    The described device can be used to measure the output of any dc powered RF source. No dummy load is required for the measurements. The device is, therefore, called the 'no-load calorimeter' (NLC). The NLC measures the power actually fed to the antenna or another useful load. It is believed that the NLC can compete successfully with directional coupler type systems in measuring the output of high-power RF sources.

  3. RF beam transmission of x-band PAA system utilizing large-area, polymer-based true-time-delay module developed using imprinting and inkjet printing

    NASA Astrophysics Data System (ADS)

    Pan, Zeyu; Subbaraman, Harish; Zhang, Cheng; Li, Qiaochu; Xu, Xiaochuan; Chen, Xiangning; Zhang, Xingyu; Zou, Yi; Panday, Ashwin; Guo, L. Jay; Chen, Ray T.

    2016-02-01

    Phased-array antenna (PAA) technology plays a significant role in modern day radar and communication networks. Truetime- delay (TTD) enabled beam steering networks provide several advantages over their electronic counterparts, including squint-free beam steering, low RF loss, immunity to electromagnetic interference (EMI), and large bandwidth control of PAAs. Chip-scale and integrated TTD modules promise a miniaturized, light-weight system; however, the modules are still rigid and they require complex packaging solutions. Moreover, the total achievable time delay is still restricted by the wafer size. In this work, we propose a light-weight and large-area, true-time-delay beamforming network that can be fabricated on light-weight and flexible/rigid surfaces utilizing low-cost "printing" techniques. In order to prove the feasibility of the approach, a 2-bit thermo-optic polymer TTD network is developed using a combination of imprinting and ink-jet printing. RF beam steering of a 1×4 X-band PAA up to 60° is demonstrated. The development of such active components on large area, light-weight, and low-cost substrates promises significant improvement in size, weight, and power (SWaP) requirements over the state-of-the-art.

  4. Design, construction, system integration, and test results of the 1 MW CW RF system for the e-gun cavity in the energy recovery LINAC at Brookhaven National Laboratory

    SciTech Connect

    Lenci,S.J.; Eisen, E. L.; Dickey, D. L.; Sainz, J. E.; Utay, P. F.; Zaltsman, A.; Lambiase, R.

    2009-05-04

    Brookhaven's ERL (Energy Recovery LINAC) requires a 1 MW CW RF system for the superconducting electron gun cavity. The system consists primarily of a klystron tube, transmitter, and High-Voltage Power Supply (HVPS). The 703.75 MHz klystron made by CPl, Inc. provides RF power of 1MW CW with efficiency of 65%. It has a single output window, diode-type electron gun, and collector capable of dissipating the entire beam power. It was fully factory tested including 24-hour heat run at 1.1 MW CWo The solid state HVPS designed by Continental Electronics provides up to 100 kV at low ripple and 2.1 MW CW with over 95% efficiency. With minimal stored energy and a fast shut-down mode no crowbar circuit is needed. Continental 's transmitter includes PLC based user interface and monitoring, RF pre-amplifier, magnet and Vac-Ion pump supplies, cooling water instrumentation, and integral safety interlock system. BNL installed the klystron, HVPS, and transmitter along with other items, such as circulator, water load, and waveguide components. The collaboration of BNL, CPI, and Continental in the design, installation, and testing was essential to the successful operation of the 1MW system.

  5. A novel surface-enhanced Raman spectroscopy substrate based on a large area of MoS2 and Ag nanoparticles hybrid system

    NASA Astrophysics Data System (ADS)

    Chen, P. X.; Qiu, H. W.; Xu, S. C.; Liu, X. Y.; Li, Z.; Hu, L. T.; Li, C. H.; Guo, J.; Jiang, S. Z.; Huo, Y. Y.

    2016-07-01

    Few layers MoS2 were directly synthesized on Ag nanoparticles (AgNPs) by thermal decomposion method to fabricate a MoS2/AgNPs hybrid system for surface-enhanced Raman scattering (SERS). The MoS2/AgNPs hybrid system shows high performance in terms of sensitivity, signal-to-noise ratio, reproducibility and stability. The minimum detected concentration from MoS2/AgNPs hybrid system for R6 G can reach 10-9 M, which is one order of magnitude lower than that from AgNPs system. The hybrid system shows the reasonable linear response between the Raman intensity and concentration that R2 is reached to 0.988. The maximum deviations of SERS intensities from 20 positions of the SERS substrate are less than 13%. Besides, the hybrid system has a good stability, the Raman intensity only drop by 20% in a month. This work can provide a basis for the fabrication of novel SERS substrates.

  6. Beam position monitoring in the AGS Linac to Booster transfer line

    SciTech Connect

    Shea, T.J.; Brodowski, J.; Witkover, R.

    1991-12-31

    A beam position monitor system has been developed and used in the commissioning of Brookhaven`s Linac to Booster transfer line. This line transports a chopped, RF modulated H- beam from the 200 MeV Linac to the AGS Booster. Over a 15dB dynamic range in beam current, the position monitor system provides a real-time, normalized position signal with an analog bandwidth of about 20 MHz. Seven directional coupler style pickups are installed in the line with each pickup sensing both horizontal and vertical position. Analog processing electronics are located in the tunnel and incorporate the amplitude modulation to phase modulation normalization technique. To avoid interference from the 200 MHz linac RF system, processing is performed at 400 MHz. This paper will provide a system overview and report results from the commissioning experience.

  7. Beam position monitoring in the AGS Linac to Booster transfer line

    SciTech Connect

    Shea, T.J.; Brodowski, J.; Witkover, R.

    1991-01-01

    A beam position monitor system has been developed and used in the commissioning of Brookhaven's Linac to Booster transfer line. This line transports a chopped, RF modulated H- beam from the 200 MeV Linac to the AGS Booster. Over a 15dB dynamic range in beam current, the position monitor system provides a real-time, normalized position signal with an analog bandwidth of about 20 MHz. Seven directional coupler style pickups are installed in the line with each pickup sensing both horizontal and vertical position. Analog processing electronics are located in the tunnel and incorporate the amplitude modulation to phase modulation normalization technique. To avoid interference from the 200 MHz linac RF system, processing is performed at 400 MHz. This paper will provide a system overview and report results from the commissioning experience.

  8. RF pulse compression in the NLC test accelerator at SLAC

    NASA Astrophysics Data System (ADS)

    Lavine, T. L.

    At the Stanford Linear Accelerator Center (SLAC), the authors are designing a Next Linear Collider (NLC) with linacs powered by x-band klystrons with RF pulse compression. The design of the linac RF system is based on x-band prototypes which have been tested at high power, and on a systems-integration test - the Next Linear Collider Test Accelerator (NLCTA) - which is currently under construction at SLAC. This paper discusses some of the systems implications of RF pulse compression, and the use of pulse compression in the NLCTA, both for peak power multiplication and for controlling, by RF phase modulation, intrapulse variations in the linac beam energy.

  9. RF pulse compression for future linear colliders

    SciTech Connect

    Wilson, P.B.

    1995-05-01

    Future (nonsuperconducting) linear colliders will require very high values of peak rf power per meter of accelerating structure. The role of rf pulse compression in producing this power is examined within the context of overall rf system design for three future colliders at energies of 1.0--1.5 TeV, 5 TeV and 25 TeV. In order keep the average AC input power and the length of the accelerator within reasonable limits, a collider in the 1.0--1.5 TeV energy range will probably be built at an x-band rf frequency, and will require a peak power on the order of 150--200 MW per meter of accelerating structure. A 5 TeV collider at 34 GHz with a reasonable length (35 km) and AC input power (225 MW) would require about 550 MW per meter of structure. Two-beam accelerators can achieve peak powers of this order by applying dc pulse compression techniques (induction linac modules) to produce the drive beam. Klystron-driven colliders achieve high peak power by a combination of dc pulse compression (modulators) and rf pulse compression, with about the same overall rf system efficiency (30--40%) as a two-beam collider. A high gain (6.8) three-stage binary pulse compression system with high efficiency (80%) is described, which (compared to a SLED-11 system) can be used to reduce the klystron peak power by about a factor of two, or alternately, to cut the number of klystrons in half for a 1.0--1.5 TeV x-band collider. For a 5 TeV klystron-driven collider, a high gain, high efficiency rf pulse compression system is essential.

  10. RF pulse compression for future linear colliders

    NASA Astrophysics Data System (ADS)

    Wilson, Perry B.

    1995-07-01

    Future (nonsuperconducting) linear colliders will require very high values of peak rf power per meter of accelerating structure. The role of rf pulse compression in producing this power is examined within the context of overall rf system design for three future colliders at energies of 1.0-1.5 TeV, 5 TeV, and 25 TeV. In order to keep the average AC input power and the length of the accelerator within reasonable limits, a collider in the 1.0-1.5 TeV energy range will probably be built at an x-band rf frequency, and will require a peak power on the order of 150-200 MW per meter of accelerating structure. A 5 TeV collider at 34 GHz with a reasonable length (35 km) and AC input power (225 MW) would require about 550 MW per meter of structure. Two-beam accelerators can achieve peak powers of this order by applying dc pulse compression techniques (induction linac modules) to produce the drive beam. Klystron-driven colliders achieve high peak power by a combination of dc pulse compression (modulators) and rf pulse compression, with about the same overall rf system efficiency (30-40%) as a two-beam collider. A high gain (6.8) three-stage binary pulse compression system with high efficiency (80%) is described, which (compared to a SLED-II system) can be used to reduce the klystron peak power by about a factor of two, or alternatively, to cut the number of klystrons in half for a 1.0-1.5 TeV x-band collider. For a 5 TeV klystron-driven collider, a high gain, high efficiency rf pulse compression system is essential.

  11. Synthesis of antibacterial film CTS/PVP/TiO2/Ag for drinking water system.

    PubMed

    Zhang, Liang; Bai, Xue; Tian, Hua; Zhong, Lvling; Ma, Cailian; Zhou, Yuanzhen; Chen, Shuangli; Li, Dongliang

    2012-08-01

    A CTS/PVP/TiO2/Ag functional film was prepared as an antibacterial composite used in storing drinking water. The orthogonal experiment showed that the optimal conditions for preparing membranes with best antibacterial activity and tensile strength are c(AgNO3)=0.08%, c(TiO2)=0.20%, c(CTS)=2.25%, and c(PVP)=3.00%. The FT-IR spectrum implies that hydrogen bands are formed between acetyl in PVP and hydroxyl in CTS molecule, and -NH and -OH of CTS have some interactions with sliver nano-particles (nano-Ags) which were reduced in situ. The SEM images show that the TiO2 particles are displayed on the surface and embedded in the film. And nano-Ags are further proved through XRD and SEM images. The DSC curves show that the film has a favorable compatibility and heat stability. In application study, it is proved that this film has sustainable antibacterial activity and is safe in use.

  12. MEMS technologies for rf communications

    NASA Astrophysics Data System (ADS)

    Wu, Qun; Kim, B. K.

    2001-04-01

    Microelectromechanical system (MEMS) represents an exciting new technology derived from the same fabricating processes used to make integrated circuits. The trends of growing importance of the wireless communications market is toward the system with minimal size, cost and power consumption. For the purpose of MEMS R&D used for wireless communications, a history and present situation of MEMS device development are reviewed in this paper, and an overview of MEMS research topics on RF communication applications and the state of the art technologies are also presented here.

  13. Technology, science, and environtmental impact of a novel Cu-Ag core-shell solderless interconnect system

    NASA Astrophysics Data System (ADS)

    Kammer, Milea Joy

    processing of the final flux/particle paste combination was optimized at a commercial test facility for printing on test boards containing a wide variety of pad shapes, sizes, and pitches and thus, validated the ability of the Cu-Ag core-shell paste to be a drop-in replacement for traditional solder paste using conventional manufacturing techniques. The second study addresses the fundamental mechanisms behind interconnect formation. An assessment of the kinetics and microstructure evolution during silver thin film dewetting and defect formation provides essential materials science knowledge to understand and control the functionality of the Cu-Ag core-shell system. From an interrupted annealing study used to quantify dewetting kinetics, a range of surface diffusion coefficients were calculated from the experimental results, assuming that surface diffusion controlled dewetting. The two order of magnitude range in calculated diffusion coefficient demonstrates that the diffusion-limited kinetic models traditionally used to quantify hillock and hole growth kinetics during thin film relaxation and dewetting do not apply to the dewetting of Ag films. The presence of interface-limited kinetics was then validated through the non-uniform growth of individual hillocks over time. Lastly, an environmental assessment compares the impacts associated with the manufacturing and materials for the Cu-Ag core-shell particle system and SAC 305, the most commonly used lead-free solder alloy that contains 96.5% tin, 3% silver, and 0.5% copper. By comparing the impacts on global warming, acidification, eutrophication, ozone depletion, ecotoxicity, smog, carcinogenics, non-carcinogenics, and respiratory effects associated with each technology, the environmental advantages and disadvantages of each system are clearly communicated. By utilizing this information and the versatility of the core-shell system, possible methods for reducing impacts of the Cu-Ag core-shell system are addressed in order to

  14. An Experimental Study of Transient Liquid Phase Bonding of the Ternary Ag-Au-Cu System Using Differential Scanning Calorimetry

    NASA Astrophysics Data System (ADS)

    Kuntz, M. L.; Panton, B.; Wasiur-Rahman, S.; Zhou, Y.; Corbin, S. F.

    2013-08-01

    An experimental approach using differential scanning calorimetry (DSC) has been applied to quantify the solid/liquid interface kinetics during the isothermal solidification stage of transient liquid phase (TLP) bonding in an Ag-Au-Cu ternary alloy solid/liquid diffusion couple. Eutectic Ag-Au-Cu foil interlayers were coupled with pure Ag base metal to study the effects of two solutes on interface motion. Experimental effects involving baseline shift and primary solidification contribute to a systematic underestimation of the fraction of liquid remaining. A temperature program has been used to quantify and correct these effects. The experimental results show a linear relationship between the interface position and the square root of the isothermal hold time. The shifting tie line composition at the interface has been shown to affect the DSC results; however, the impact on the calculated interface kinetics has been shown to be minimal in this case. This work has increased the knowledge of isothermal solidification in ternary alloy systems and developed accurate experimental methods to characterize these processes, which is valuable for designing TLP bonding schedules.

  15. Atomic mechanisms of. gamma. ' precipitate plate growth in the Al-Ag system

    SciTech Connect

    Howe, J.M.

    1985-03-01

    Energy-dispersive x-ray spectroscopy results that the precipitates have the composition Ag/sub 2/Al. High-resolution electron microscopy of ..gamma..' precipitates in both <110>//<1120> and <111>//<0001> orientations shows that all interfaces of the precipitate are largely coherent with the matrix and are faceted along low-energy (111) and (110) matrix plans, due to the influence of surface and elastic strain energies on the transformation. Further comparison between experimental and calculated high-resolution images of the precipitate/matrix interface and of Shockley partial dislocation ledges on the precipitate faces demonstrates that both thickening and lengthening of ..gamma..' precipitate plates occurs by the passage of the Shockley partial dislocations along alternate (111) matrix planes by a terrace-ledge-kink mechanism. These images and electron diffraction information also indicate that the ..gamma..' precipitates are ordered, where the A-planes in the precipitate contain nearly pure Ag and the B-planes have the composition Al/sub 2/Ag, and that the limiting reaction in the growth process is the substitutional diffusion of Ag cross kinks in the Shockley partial dislocations, which terminate in the Ag-rich A-planes. The terraces between ledges are atomically flat and ledges are uniformly stepped-down from the centers to the edges of isolated precipitates. Convergent-beam electron diffraction (CBED) analyses of ..gamma..' precipitates indicate that they have the space group P6/sub 3//mmc. Effect of specimen thickness on symmetry determinations by CBED was also examined for an ..cap alpha..-titanium sample. Results show that the symmetries observed in CBED patterns from thin specimens may be due to the limited thickness of the specimen, rather than to the actual space group of the material.

  16. RF Gun Optimization Study

    SciTech Connect

    A. S. Hofler; P. Evtushenko; M. Krasilnikov

    2007-08-01

    Injector gun design is an iterative process where the designer optimizes a few nonlinearly interdependent beam parameters to achieve the required beam quality for a particle accelerator. Few tools exist to automate the optimization process and thoroughly explore the parameter space. The challenging beam requirements of new accelerator applications such as light sources and electron cooling devices drive the development of RF and SRF photo injectors. RF and SRF gun design is further complicated because the bunches are space charge dominated and require additional emittance compensation. A genetic algorithm has been successfully used to optimize DC photo injector designs for Cornell* and Jefferson Lab**, and we propose studying how the genetic algorithm techniques can be applied to the design of RF and SRF gun injectors. In this paper, we report on the initial phase of the study where we model and optimize gun designs that have been benchmarked with beam measurements and simulation.

  17. Immunofluorescence detection of new antigen-antibody system (delta/anti-delta) associated to hepatitis B virus in liver and in serum of HBsAg carriers.

    PubMed Central

    Rizzetto, M; Canese, M G; Aricò, S; Crivelli, O; Trepo, C; Bonino, F; Verme, G

    1977-01-01

    A new antigen-antibody system associated with the hepatitis B virus and immunologically distinct from the HB surface, core, and e systems is reported. The new antigen, termed delta, was detected by direct immunofluorescence only in the liver cell nuclei of patients with HBsAg positive chronic liver disease. At present, the intrahepatic expression of HBcAg and delta antigen appears to be mutually exclusive. No ultrastructural aspect corresponding to the delta antigen could be identified under the electron microscope. delta antibody was found in the serum of chronic HBsAg carriers, with a higher prevalence in patients with liver damage. The nuclear fluorescence patterns of HBcAg and delta antigen were similar; it is only possible to discriminate between the two antigens by using the respective specific antisera. Images Figure PMID:75123

  18. Rf2a and rf2b transcription factors

    DOEpatents

    Beachy, Roger N.; Petruccelli, Silvana; Dai, Shunhong

    2007-10-02

    A method of activating the rice tungro bacilliform virus (RTBV) promoter in vivo is disclosed. The RTBV promoter is activated by exposure to at least one protein selected from the group consisting of Rf2a and Rf2b.

  19. Quad RF power meter

    SciTech Connect

    Stone, D.W.

    1987-09-01

    This report shows how to construct a four-channel RF power meter from circuit boards and components found in a Hewlett Packard Model 432A Power Meter. Included are descriptions of necessary modifications, electrical circuit diagrams, and a parts list. Each of the four power meters is compatible with a Hewlett Packard 432A Power Meter.

  20. AC/RF Superconductivity

    SciTech Connect

    Ciovati, Gianluigi

    2015-02-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  1. RF cavity using liquid dielectric for tuning and cooling

    DOEpatents

    Popovic, Milorad; Johnson, Rolland P.

    2012-04-17

    A system for accelerating particles includes an RF cavity that contains a ferrite core and a liquid dielectric. Characteristics of the ferrite core and the liquid dielectric, among other factors, determine the resonant frequency of the RF cavity. The liquid dielectric is circulated to cool the ferrite core during the operation of the system.

  2. TiInZnO/Ag/TiInZnO multilayer films for transparent conducting electrodes of dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Kim, Ho-Hyeong; Kim, Eun-Mi; Lee, Kyung-Ju; Park, Jae-Young; Lee, Yu-Ri; Shin, Dong-Chan; Hwang, Tae-Jin; Heo, Gi-Seok

    2014-03-01

    Ti-In-Zn-O (TIZO) and TIZO/Ag/TIZO multilayer transparent films were prepared at room temperature on glass substrates using an RF/DC magnetron sputtering system. The optical and electrical properties of the multilayer structures were examined according to the thickness of each TIZO/Ag/TIZO layer. A transparent and conductive film with a sheet resistance of 11.1 Ω/□ and a transmittance of 86.9% at 550 nm (94.2%, normalized to the glass substrate) was obtained at a TIZO/Ag/TIZO thickness of 100/8/42 nm. The TIZO and TIZO/Ag/TIZO multilayer films exhibited higher mechanical resistances against an increasing load of external scratches than the indium tin oxide (ITO) film. Overall, the properties of the TIZO/Ag/TIZO multilayer films were comparable or superior to those of the ITO/Ag/ITO multilayer. The deposited TIZO/Ag/TIZO multilayer films were used in the fabrication of dye-sensitized solar cells (DSSCs) as the transparent electrode. The TIZO/Ag/TIZO multilayer-based DSSCs exhibited a short circuit photocurrent density of 9.4 mA/cm2, a photocurrent of 613 mV, and an overall cell efficiency of 3.1% at a light intensity of one sun.

  3. Development of a micro-step voltage-fed actuator with a novel stepper motor for automobile AGS systems.

    PubMed

    Rhyu, Se-Hyun; Lee, Jeong-Jong; Gu, Bon-Gwan; Choi, Byung-Dae; Lim, Jung-Hyuk

    2014-05-05

    This paper presents an improved micro-step voltage-fed actuator for an automobile active grill shutter (AGS) system. A novel structured stepper motor, which contains both the main and auxiliary teeth in the stator, is proposed for the actuator. In a normal permanent magnet (PM) motor coils are generally wound on all the stator teeth, however, in the proposed motor, the winding is only on the main teeth. Because of the absence of coils in the auxiliary teeth, the proposed stepper motor possesses the following advantages: simple structure, lighter weight, smaller volume, and less time consumption. The unique auxiliary poles in the stepper motor supply the flux path to increase the step resolution even without any coils. The characteristics of the proposed stepper motor were investigated using finite element analysis. In particular, the effect of the magnetization distribution of the PM on the motor performance was investigated during the analysis. Cogging torque, which causes noise and vibration issues, was minimized by the tooth-shape optimization. In addition, a micro-step voltage-fed algorithm was implemented for a high-resolution position control. By employing a current close to a sine wave using space vector pulse-width modulation, a high-quality current waveform with a high resolution was obtained. Finally, the proposed prototype was fabricated, and the cogging torque, back-electromotive force, and current characteristics were measured by mounting the prototype on the AGS system. Both the analysis and experimental results validate the performance improvement from the proposed motor and its possible application for the flap control of the AGS system.

  4. Substrate-Linked Conformational Change in the Periplasmic Component of a Cu(I)/Ag(I) Efflux System

    SciTech Connect

    Bagai, I.; Liu, W.; Rensing, C.; Blackburn, N.J.; McEvoy, M.M.

    2009-06-02

    Gram-negative bacteria utilize dual membrane resistance nodulation division-type efflux systems to export a variety of substrates. These systems contain an essential periplasmic component that is important for assembly of the protein complex. We show here that the periplasmic protein CusB from the Cus copper/silver efflux system has a critical role in Cu(I) and Ag(I) binding. Isothermal titration calorimetry experiments demonstrate that one Ag(I) ion is bound per CusB molecule with high affinity. X-ray absorption spectroscopy data indicate that the metal environment is an all-sulfur 3-coordinate environment. Candidates for the metal-coordinating residues were identified from sequence analysis, which showed four conserved methionine residues. Mutations of three of these methionine residues to isoleucine resulted in significant effects on CusB metal binding in vitro. Cells containing these CusB variants also show a decrease in their ability to grow on copper-containing plates, indicating an important functional role for metal binding by CusB. Gel filtration chromatography demonstrates that upon binding metal, CusB undergoes a conformational change to a more compact structure. Based on these structural and functional effects of metal binding, we propose that the periplasmic component of resistance nodulation division-type efflux systems plays an active role in export through substrate-linked conformational changes.

  5. Enhanced formation of silver nanoparticles in Ag+-NOM-iron(II, III) systems and antibacterial activity studies.

    PubMed

    Adegboyega, Nathaniel F; Sharma, Virender K; Siskova, Karolina M; Vecerova, Renata; Kolar, Milan; Zbořil, Radek; Gardea-Torresdey, Jorge L

    2014-03-18

    This work reports the role of iron redox pair (Fe(3+)/Fe(2+)) in the formation of naturally occurring silver nanoparticles (AgNPs) in the aquatic environment. The results showed that Fe(3+) or Fe(2+) ions in the mixtures of Ag(+) and natural organic matter enhanced the formation of AgNPs. The formation of AgNPs depended on pH and types of organic matter. Increase in pH enhanced the formation of AgNPs, and humic acids as ligands showed higher formation of AgNPs compared to fulvic acids. The observed results were described by considering the potentials of redox pairs of silver and iron species and the possible species involved in reducing silver ions to AgNPs. Dynamic light scattering and transmission electron microscopy measurements of AgNPs revealed mostly bimodal size distribution with decrease in size of AgNPs due to iron species in the reaction mixture. Minimum inhibitory concentration of AgNPs needed to inhibit the growth of various bacterial species suggested the role of surfaces of tested Gram-positive and Gram-negative bacteria. Stability study of AgNPs, formed in Ag(+)-humic acid/fulvic acids-Fe(3+) mixtures over a period of several months showed high stability of the particles with significant increase in surface plasmon resonance peak. The environmental implications of the results in terms of fate, transport, and ecotoxicity of organic-coated AgNPs are briefly presented. PMID:24524189

  6. L-band Photocathode RF gun at KEK-STF

    NASA Astrophysics Data System (ADS)

    Sugiyama, H.; Takahashi, Y.; Hayano, H.; Urakawa, J.; Kashiwagi, S.; Isoyama, G.; Kato, R.; Sugimoto, N.; Kuriki, M.

    2011-05-01

    The superconducting RF test facility (STF) in KEK is a facility to promote R&D of the International Linear Collider (ILC) cavities and cryomodule. L-band photocathode RF gun has been developed at KEK-STF as an electron beam source for cryomodule test scheduled in autumn of 2011. The RF cavity of the gun will be operated with a 1.3 GHz RF frequency, 1 msec RF pulse width, 5 Hz repetition rate at normal conductivity. The cavity was prepared by collaborative work with DESY and FNAL, and fabricated by FNAL. The RF conditioning of the cavity has been started since April 2010. A cesium telluride thin film as a photocathode material has been adopted, and the preparation equipment for cesium telluride has been newly designed and constructed. By using this new system, a fabrication and a performance estimation of the cesium telluride thin film as a photocathode are the next step of the research.

  7. Destabilization of Ag nanoislands on Ag(100) by adsorbed sulfur

    SciTech Connect

    Shen, Mingmin; Russell, Selena M.; Liu, Da-Jiang; Thiel, Patricia A.

    2011-10-17

    Sulfur accelerates coarsening of Ag nanoislands on Ag(100) at 300 K, and this effect is enhanced with increasing sulfur coverage over a range spanning a few hundredths of a monolayer, to nearly 0.25 monolayers. We propose that acceleration of coarsening in this system is tied to the formation of AgS{sub 2} clusters primarily at step edges. These clusters can transport Ag more efficiently than can Ag adatoms (due to a lower diffusion barrier and comparable formation energy). The mobility of isolated sulfur on Ag(100) is very low so that formation of the complex is kinetically limited at low sulfur coverages, and thus enhancement is minimal. However, higher sulfur coverages force the population of sites adjacent to step edges, so that formation of the cluster is no longer limited by diffusion of sulfur across terraces. Sulfur exerts a much weaker effect on the rate of coarsening on Ag(100) than it does on Ag(111). This is consistent with theory, which shows that the difference between the total energy barrier for coarsening with and without sulfur is also much smaller on Ag(100) than on Ag(111).

  8. AgI/Ag{sub 3}PO{sub 4} hybrids with highly efficient visible-light driven photocatalytic activity

    SciTech Connect

    Katsumata, Hideyuki; Hayashi, Takahiro; Taniguchi, Masanao; Suzuki, Tohru; Kaneco, Satoshi

    2015-03-15

    Highlights: • AgI/Ag{sub 3}PO{sub 4} hybrid was prepared via an in situ anion-exchange method. • AgI/Ag{sub 3}PO{sub 4} displays the excellent photocatalytic activity under visible light. • AgI/Ag{sub 3}PO{sub 4} readily transforms to be Ag@AgI/Ag{sub 3}PO{sub 4} system. • h{sup +} and O{sub 2}{sup ·−} play the major role in the AO 7 decolorization over AgI/Ag{sub 3}PO{sub 4}. • The activity enhancement is ascribed to a Z-scheme system composed of Ag{sub 3}PO{sub 4}, Ag and AgI. - Abstract: Highly efficient visible-light-driven AgI/Ag{sub 3}PO{sub 4} hybrid photocatalysts with different mole ratios of AgI were prepared via an in situ anion-exchange method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) technique. Under visible light irradiation (>420 nm), the AgI/Ag{sub 3}PO{sub 4} photocatalysts displayed the higher photocatalytic activity than pure Ag{sub 3}PO{sub 4} and AgI for the decolorization of acid orange 7 (AO 7). Among the hybrid photocatalysts, AgI/Ag{sub 3}PO{sub 4} with 80% of AgI exhibited the highest photocatalytic activity for the decolorization of AO 7. X-ray photoelectron spectroscopy (XPS) results revealed that AgI/Ag{sub 3}PO{sub 4} readily transformed to be Ag@AgI/Ag{sub 3}PO{sub 4} system while the photocatalytic activity of AgI/Ag{sub 3}PO{sub 4} remained after 5 recycling runs. In addition, the quenching effects of different scavengers displayed that the reactive h{sup +} and O{sub 2}{sup ·−} play the major role in the AO 7 decolorization. The photocatalytic activity enhancement of AgI/Ag{sub 3}PO{sub 4} hybrids can be ascribed to the efficient separation of electron–hole pairs through a Z-scheme system composed of Ag{sub 3}PO{sub 4}, Ag and AgI, in which Ag nanoparticles act as the charge separation center.

  9. RF power recovery feedback circulator

    DOEpatents

    Sharamentov, Sergey I.

    2011-03-29

    A device and method for improving the efficiency of RF systems having a Reflective Load. In the preferred embodiment, Reflected Energy from a superconducting resonator of a particle accelerator is reintroduced to the resonator after the phase of the Reflected Energy is aligned with the phase of the Supply Energy from a RF Energy Source. In one embodiment, a Circulator is used to transfer Reflected Energy from the Reflective Load into a Phase Adjuster which aligns the phase of the Reflected Energy with that of the Supply Energy. The phase-aligned energy is then combined with the Supply Energy, and reintroduced into the Reflective Load. In systems having a constant phase shift, the Phase Adjuster may be designed to shift the phase of the Reflected Energy by a constant amount using a Phase Shifter. In systems having a variety (variable) phase shifts, a Phase Shifter controlled by a phase feedback loop comprising a Phase Detector and a Feedback Controller to account for the various phase shifts is preferable.

  10. RF Performance of Membrane Aperture Shells

    NASA Technical Reports Server (NTRS)

    Flint, Eirc M.; Lindler, Jason E.; Thomas, David L.; Romanofsky, Robert

    2007-01-01

    This paper provides an overview of recent results establishing the suitability of Membrane Aperture Shell Technology (MAST) for Radio Frequency (RF) applications. These single surface shells are capable of maintaining their figure with no preload or pressurization and minimal boundary support, yet can be compactly roll stowed and passively self deploy. As such, they are a promising technology for enabling a future generation of RF apertures. In this paper, we review recent experimental and numerical results quantifying suitable RF performance. It is shown that candidate materials possess metallic coatings with sufficiently low surface roughness and that these materials can be efficiently fabricated into RF relevant doubly curved shapes. A numerical justification for using a reflectivity metric, as opposed to the more standard RF designer metric of skin depth, is presented and the resulting ability to use relatively thin coating thickness is experimentally validated with material sample tests. The validity of these independent film sample measurements are then confirmed through experimental results measuring RF performance for reasonable sized doubly curved apertures. Currently available best results are 22 dBi gain at 3 GHz (S-Band) for a 0.5m aperture tested in prime focus mode, 28dBi gain for the same antenna in the C-Band (4 to 6 GHz), and 36.8dBi for a smaller 0.25m antenna tested at 32 GHz in the Ka-Band. RF range test results for a segmented aperture (one possible scaling approach) are shown as well. Measured antenna system actual efficiencies (relative to the unachievable) ideal for these on axis tests are generally quite good, typically ranging from 50 to 90%.

  11. Robust multiplatform RF emitter localization

    NASA Astrophysics Data System (ADS)

    Al Issa, Huthaifa; Ordóñez, Raúl

    2012-06-01

    In recent years, position based services has increase. Thus, recent developments in communications and RF technology have enabled system concept formulations and designs for low-cost radar systems using state-of-the-art software radio modules. This research is done to investigate a novel multi-platform RF emitter localization technique denoted as Position-Adaptive RF Direction Finding (PADF). The formulation is based on the investigation of iterative path-loss (i.e., Path Loss Exponent, or PLE) metrics estimates that are measured across multiple platforms in order to autonomously adapt (i.e. self-adjust) of the location of each distributed/cooperative platform. Experiments conducted at the Air-Force Research laboratory (AFRL) indicate that this position-adaptive approach exhibits potential for accurate emitter localization in challenging embedded multipath environments such as in urban environments. The focus of this paper is on the robustness of the distributed approach to RF-based location tracking. In order to localize the transmitter, we use the Received Signal Strength Indicator (RSSI) data to approximate distance from the transmitter to the revolving receivers. We provide an algorithm for on-line estimation of the Path Loss Exponent (PLE) that is used in modeling the distance based on Received Signal Strength (RSS) measurements. The emitter position estimation is calculated based on surrounding sensors RSS values using Least-Square Estimation (LSE). The PADF has been tested on a number of different configurations in the laboratory via the design and implementation of four IRIS wireless sensor nodes as receivers and one hidden sensor as a transmitter during the localization phase. The robustness of detecting the transmitters position is initiated by getting the RSSI data through experiments and then data manipulation in MATLAB will determine the robustness of each node and ultimately that of each configuration. The parameters that are used in the functions are

  12. Nanostructure of wetting triple line in a Ag-Cu-Ti/Si{sub 3}N{sub 4} reactive system

    SciTech Connect

    Nomura, M.; Iwamoto, C.; Tanaka, S.I.

    1999-01-15

    Nanometer scale structures around wetting triple lines were studied in a Ag-Cu-Ti/Si{sub 3}N{sub 4} reactive system. Changes in the contact angle and radius of the molten metal on the substrate as a function of time were also measured in the system as macroscopic wetting behaviors. The macroscopic wetting behaviors showed two wetting stages and double layered reaction products consisting of upper Ti{sub 5}Si{sub 3} and lower TiN layers were observed in both first and second stages. The reaction product always lay in front of the triple line defined as a triple junction of Ag-Cu-Ti alloy/Ti{sub 5}Si{sub 3}/atmosphere. At the front of the reaction product, a dominant phase changed from TiN in the first stage to Ti{sub 5}Si{sub 3} in the second stage. It is considered that the structural change is one of the reasons why the macroscopic wetting behavior changed, and that the structural change was caused by a decrease of Ti activity as the reactive wetting progressed.

  13. An application of Ag(III) complex chemiluminescence system for the determination of enoxacin in capsule and biological fluid.

    PubMed

    Chen, Peiyun; Sun, Hanwen

    2010-01-01

    Ag(III) complex chemiluminescence (CL) system was applied for the determination of enoxacin (ENX). The CL conditions of [Ag(HIO(6))(2)](5-)-H(2)SO(4)-ENX systems without any luminescence reagent were investigated and optimized. Under the optimized conditions, the CL intensity was proportional to the concentration of ENX in the range from 6.6 × 10(-5) to 3.3 × 10(-3) g/L. The limit of detection (s/n = 3) was 2.0 × 10(-5) g/L. The recovery of ENX from the spiked pharmaceutical preparations was in the range of 82.9-108% with a relative standard deviation of 1.9-3.0%. For spiked serum and urine samples the recovery of ENX was in the range of 83.7-110% with a relative standard deviation of 1.1-2.8%. The proposed method was applied successfully to the determination of the drug in capsule, serum and urine samples.

  14. Preparation of Carbon-Doped TiO2 Nanopowder Synthesized by Droplet Injection of Solution Precursor in a DC-RF Hybrid Plasma Flow System

    NASA Astrophysics Data System (ADS)

    Jang, Juyong; Takana, Hidemasa; Ando, Yasutaka; Solonenko, Oleg P.; Nishiyama, Hideya

    2013-08-01

    Carbon-doped titanium dioxide nanopowder has received much attention because of its higher photocatalytic performance, which is practically activated not only by UV, but also by visible light irradiation. In the present study, C-TiO2 nanopowder was synthesized by droplet injection of solution precursor in a DC-RF hybrid plasma flow system, resulting in higher photocatalytic performance even under visible light irradiation. In-flight C-TiO2 nanoparticles reacted with the high concentration of carbon in plasma flow and were then deposited on the surfaces of two quartz tubes in the upstream and downstream regions of this system. The collected C-TiO2 nanopowder contained anatase-rutile mixed-phase TiO2 and TiC, the contents of which depended on the location of the powder collection, the temperature, and the duration of plasma treatment. Highly functional C-TiO2 nanopowder collected in the downstream region exhibited a higher degradation rate of methylene blue than that of single-phase anatase TiO2, even under visible light irradiation, in spite of being TiC.

  15. DEVELOPMENT OF A HIGH-TEMPERATURE CERAMIC BRAZE: ANALYSIS OF PHASE EQUILIBRIA IN THE Pd-Ag-CuOx SYSTEM

    SciTech Connect

    Weil, K. Scott; Darsell, Jens T.

    2006-01-18

    This paper describes the effects of small palladium additions on the phase equilibria in the Ag-CuOx system. Below a concentration of 5 mol%, palladium was found to increase the temperature of the eutectic reaction present in the pseudobinary system, but have little effect on a higher temperature monotectic reaction. However once enough palladium was added to increase the pseudoternary solidus temperature to that of the lower boundary for this three-phase field (~970°C), the lower boundary begins to increase in temperature as well. The addition of palladium also causes the original eutectic point to move to lower silver concentrations, which also causes a convergence of the two new three-phase fields, CuOx + L1 + L2 and CuOx + α + L1. This suggests that with higher palladium concentrations, a peritectic reaction, α + L1 + L2 → CuOx, may eventually be observed in the system.

  16. RF pulsed heating

    NASA Astrophysics Data System (ADS)

    Pritzkau, David Peace

    RF pulsed heating is a process by which a metal is heated from magnetic fields on its surface due to high-power pulsed RF. When the thermal stresses induced are larger than the elastic limit, microcracks and surface roughening will occur due to cyclic fatigue. Pulsed heating limits the maximum magnetic field on the surface and through it the maximum achievable accelerating gradient in a normal conducting accelerator structure. An experiment using circularly cylindrical cavities operating in the TE011 mode at a resonant frequency of 11.424 GHz is designed to study pulsed heating on OFE copper, a material commonly used in normal conducting accelerator structures. The high-power pulsed RF is supplied by an X-band klystron capable of outputting 50 MW, 1.5 μs pulses. The test pieces of the cavity are designed to be removable to allow testing of different materials with different surface preparations. A diagnostic tool is developed to measure the temperature rise in the cavity utilizing the dynamic Q change of the resonant mode due to heating. The diagnostic consists of simultaneously exciting a TE012 mode to steady-state in the cavity at 18 GHz and measuring the change in reflected power as the cavity is heated from high-power pulsed RF. Two experimental runs were completed. One run was executed at a calculated temperature rise of 120 K for 56 × 106 pulses. The second run was executed at a calculated temperature rise of 82 K for 86 × 106 pulses. Scanning electron microscope pictures show extensive damage occurring in the region of maximum temperature rise on the surface of the test pieces.

  17. RF Pulsed Heating

    NASA Astrophysics Data System (ADS)

    Pritzkau, D. P.

    2002-01-01

    RF pulsed heating is a process by which a metal is heated from magnetic elds on its surface due to high-power pulsed RF. When the thermal stresses induced are larger than the elastic limit, microcracks and surface roughening will occur due to cyclic fatigue. Pulsed heating limits the maximum magnetic eld on the surface and through it the maximum achievable accelerating gradient in a normal conducting accelerator structure. An experiment using circularly cylindrical cavities operating in the TE011 mode at a resonant frequency of 11:424 GHz is designed to study pulsed heating on OFE copper, a material commonly used in normal conducting accelerator structures. The high-power pulsed RF is supplied by an X-band klystron capable of outputting 50 MW, 1:5 s perent surface preparations.he cavity are designed to A diagnostic tool is developed to measure the temperature rise in the cavity utilizing the dynamic Q change of the resonant mode due to heating. The diagnostic consists of simultaneously exciting a TE012 mode to steady-state in the cavity at 18 GHz and measuring the change in re ected power as the cavity is heated from high-power pulsed RF. Two experimental runs were completed. One run was executed at a calculated temperature rise of 120 K for 56 106 pulses. The second run was executed at a calculated temperature rise of 82 K for 86106 pulses. Scanning electron microscope pictures show extensive damage occurring in the region of maximum temperature rise on the surface of the test pieces.

  18. Bunched beam echos in the AGS

    SciTech Connect

    Kewisch, J.; Brennan, J.M.

    1998-08-01

    Beam echos have been measured at FNAL and CERN in coasting beams. A coherent oscillation introduced by a short RF burst decoheres quickly, but a coherent echo of this oscillation can be observed if the decohered oscillation is bounced off a second RF burst. In this report the authors describe first longitudinal echo measurements of bunched beam in the AGS accelerator. They applied a method proposed by Stupakov for transverse beam echos, where the initial oscillation is produced by a dipole kick and is bounced off a quadrupole kick. In the longitudinal case the dipole and quadrupole kicks are produced by cavities operating at a 90 and 0{degree} phase shift, respectively.

  19. Interatomic interactions and thermodynamic parameters in dilute solid solutions of the Ag-Au system

    NASA Astrophysics Data System (ADS)

    Bogdanov, V. I.; Bol'shov, L. A.; Korneichuk, E. A.; Popov, V. A.; Korneichuk, S. K.; Badanin, D. A.

    2015-07-01

    The thermodynamic parameters of interaction and the enthalpy parameters are of fundamental importance in the theory of solutions, i.e., the coefficients of the expansion of partial excess thermodynamic functions into series in terms of the concentrations of the dissolved components. In the approximation of pairwise interactions between the impurity atoms in the solution, the above parameters can be computed using the methods of the density-functional theory in the electron theory of alloys. As an example, the substitutional solid solutions of Au in Ag have been chosen, which are formed by atoms of the components with close chemical properties, in which the deformation interactions should be small, and in which there is no need to take into account the complex magnetic contributions to the pair potentials. The total energy of the dilute solution of Au in Ag and the contributions from the chemical and strain-induced interactions to the potentials of pairwise interactions are calculated up to the seventh coordination shell. Quite satisfactory agreement with the thermodynamic parameters obtained from the experimental data has been obtained.

  20. RF Spectroscopy on a Homogeneous Fermi Gas

    NASA Astrophysics Data System (ADS)

    Yan, Zhenjie; Mukherjee, Biswaroop; Patel, Parth; Struck, Julian; Zwierlein, Martin

    2016-05-01

    Over the last two decades RF spectroscopy has been established as an indispensable tool to probe a large variety of fundamental properties of strongly interacting Fermi gases. This ranges from measurement of the pairing gap over tan's contact to the quasi-particle weight of Fermi polarons. So far, most RF spectroscopy experiments have been performed in harmonic traps, resulting in an averaged response over different densities. We have realized an optical uniform potential for ultracold Fermi gases of 6 Li atoms, which allows us to avoid the usual problems connected to inhomogeneous systems. Here we present recent results on RF spectroscopy of these homogeneous samples with a high signal to noise ratio. In addition, we report progress on measuring the contact of a unitary Fermi gas across the normal to superfluid transition.

  1. Technology, science, and environtmental impact of a novel Cu-Ag core-shell solderless interconnect system

    NASA Astrophysics Data System (ADS)

    Kammer, Milea Joy

    processing of the final flux/particle paste combination was optimized at a commercial test facility for printing on test boards containing a wide variety of pad shapes, sizes, and pitches and thus, validated the ability of the Cu-Ag core-shell paste to be a drop-in replacement for traditional solder paste using conventional manufacturing techniques. The second study addresses the fundamental mechanisms behind interconnect formation. An assessment of the kinetics and microstructure evolution during silver thin film dewetting and defect formation provides essential materials science knowledge to understand and control the functionality of the Cu-Ag core-shell system. From an interrupted annealing study used to quantify dewetting kinetics, a range of surface diffusion coefficients were calculated from the experimental results, assuming that surface diffusion controlled dewetting. The two order of magnitude range in calculated diffusion coefficient demonstrates that the diffusion-limited kinetic models traditionally used to quantify hillock and hole growth kinetics during thin film relaxation and dewetting do not apply to the dewetting of Ag films. The presence of interface-limited kinetics was then validated through the non-uniform growth of individual hillocks over time. Lastly, an environmental assessment compares the impacts associated with the manufacturing and materials for the Cu-Ag core-shell particle system and SAC 305, the most commonly used lead-free solder alloy that contains 96.5% tin, 3% silver, and 0.5% copper. By comparing the impacts on global warming, acidification, eutrophication, ozone depletion, ecotoxicity, smog, carcinogenics, non-carcinogenics, and respiratory effects associated with each technology, the environmental advantages and disadvantages of each system are clearly communicated. By utilizing this information and the versatility of the core-shell system, possible methods for reducing impacts of the Cu-Ag core-shell system are addressed in order to

  2. E sub T distributions, nuclear stopping'', and correlations among measurements from the 4 detector systems in AGS E802

    SciTech Connect

    Tannenbaum, M.J.

    1990-04-01

    As part of AGS Experiment 802, an array of 245 Lead Glass blocks, covering half the azimuth, with a polar angular acceptance approximately 8{degree} {le} {theta} {le} 32{degree}, which corresponds roughly to a laboratory pseudo rapidity range 1.25 {le} {eta} {le} 2.50 with good acceptance, when edges and corners are taken into account, measured the transverse energy (E{sub T}) distributions from primary beams of protons, {sup 16}O, and {sup 28}Si, at 14.6 A Gev/c, incident on targets of Be, Al, Cu and Au. The lead glass is most sensitive to electromagnetic radiation, but also responds to charged hadrons. The total detector response provides a good measure of the global pion yield in the central rapidity region of these reactions. Correlations among the 4 detector systems in E802 are shown to be a powerful diagnostic tool. Latest results of the analysis in progress, including dE{sub T}/d{eta} distributions, are presented, with emphasis on the proton -- nucleus data. Additionally, these data, and previous measurements of pseudorapidity distributions of multiplicity and Transverse Energy at both the AGS and CERN are analyzed in an acceptance-independent and model-independent method, with the conclusion that simple considerations of nuclear geometry do not provide an explanation of the different {radical}{sup s}NN dependences observed in {sup 16}O + Au and p-p reactions. 37 refs., 25 figs.

  3. Development of a dual-pulse RF driver for an S-band (= 2856 MHz) RF electron linear accelerator

    NASA Astrophysics Data System (ADS)

    Cha, Sungsu; Kim, Yujong; Lee, Byeong-No; Lee, Byung Cheol; Cha, Hyungki; Ha, Jang Ho; Park, Hyung Dal; Lee, Seung Hyun; Kim, Hui Su; Buaphad, Pikad

    2016-04-01

    The radiation equipment research division of Korea Atomic Energy Research Institute has developed a Container Inspection System (CIS) using a Radio Frequency (RF) electron linear accelerator for port security. The primary purpose of the CIS is to detect nuclear materials and explosives, as well country-specific prohibited substances, e.g., smuggled. The CIS consists of a 9/6 MeV dualenergy electron linear accelerator for distinguishing between organic and inorganic materials. The accelerator consists of an electron gun, an RF accelerating structure, an RF driver, a modulator, electromagnets, a cooling system, a X-ray generating target, X-ray collimator, a detector, and a container moving system. The RF driver is an important part of the configuration because it is the RF power source: it supplies the RF power to the accelerating structure. A unique aspect of the RF driver is that it generates dual RF power to generate dual energy (9/6 MeV). The advantage of this RF driver is that it can allow the pulse width to vary and can be used to obtain a wide range of energy output, and pulse repetition rates up to 300 Hz. For this reason, 140 W (5 MW - 9 MeV) and 37 W (3.4 MW - 6 MeV) power outputs are available independently. A high power test for 20 minutes demonstrate that stable dual output powers can be generated. Moreover, the dual power can be applied to the accelerator which has stable accelerator operation. In this paper, the design, fabrication and high power test of the RF driver for the RF electron linear accelerator (linac) are presented.

  4. Recent developments in superconducting cavity RF control

    NASA Astrophysics Data System (ADS)

    Simrock, Stefan

    2005-02-01

    Presently a large number of superconducting accelerators under construction or proposed impose stringent requirements on the rf control of the accelerating fields, operability, and reliability. The accelerator application range from linear colliders, UV-FELs and X-FELs, ERL based light sources, high power proton accelerators to heavy ion accelerators. Examples are TESLA and NLC, the European XFEL and Lux, the Cornell ERL based light source, the high power ERL based IR-FEL at JLAB, the neutron spallation source SNS, the heavy ion accelerator RIA, and the energy upgrade of the CEBAF accelerator at JLAB. The requirements on the rf systems range from low to high current, medium to high gradient, and relativistic to non-relativistics beam. With the technology in analog and digital electronics developing rapidly, the technology for rf feedback system is changing more and more from analog or hybrid systems towards fully digital systems. Todays DSPs and FPGAs can process sophisticated feedback algorithms on a time scale of some 100 ns to a few us with ADCs and DACs with about 100 MHz bandwidth at 14 bit and latencies less than 100 ns available to inter-face to the field detectors and field control actuators. Also fast analog multiplier technology allows for field detection and actuators for rf control with high linearity, measurement and control bandwidth while maintaining low noise levels.

  5. Pulsed power supply system for the fast quadrupoles in the AGS

    SciTech Connect

    Nawrocky, R.J.; Lambiase, R.F.

    1983-01-01

    In the acceleration of polarized protons in the AGS, a number of depolarizing resonances will be encountered. Depolarization due to the so-called intrinsic resonances will be minimized by crossing each resonance in less than one beam revolution period (approx. 2 ..mu..s). This will be accomplished with a set of twelve fast tune-shifting quadrupoles distributed symmetrically around the ring. During a typical acceleration cycle, the fast quads will be energized with a burst of alternating polarity, fast rise/slow fall triangular current pulses. The amplitude of these pulses will vary from 160 A to about 2700 A peak. This paper describes the development of the pulsed power supply for the fast quads, the construction of a prototype modulator, and some of the initial test results obtained with the prototype.

  6. Applying an intelligent and automated emissions measurement system to characterize the RF environment for supporting wireless technologies

    SciTech Connect

    Keebler, P. F.; Phipps, K. O.

    2006-07-01

    The use of wireless technologies in commercial and industrial facilities has grown significantly in the past several years. New applications of wireless technologies with increasing frequency and varying radiated power are being developed everyday. Wireless application specialists and end users have already identified several sources of electromagnetic interference (EMI) in these facilities. Interference has been reported between wireless devices and between these devices and other types of electronic equipment either using frequencies in the unlicensed wireless spectrum or equipment that may generate undesired man-made noise in this spectrum. Facilities that are not using the wireless band should verify the spectral quality of that band and the electromagnetic compatibility (EMC) integrity of safety-related power and signal cables before installing wireless technologies. With the introduction of new wireless devices in the same electromagnetic space where analog and digital I and C systems and cables must co-exist, the ability of facility managers to manage their spectra will dictate the degree of interference between wireless devices and other electronic equipment. Because of the unknowns associated with interference with analog and digital I and C systems in the wireless band, nuclear power plants have been slow to introduce wireless technologies in plant areas. With the application of newly developed advanced radiated emissions measurement systems that can record, process, and analyze radiated and conducted emissions in a cost-effective manner, facility managers can more reliably characterize potential locations for wireless technologies, including potential coupling effects with safety-related power and signal cables, with increased confidence that the risks associated with creating an interference can be significantly reduced. This paper will present an effective philosophy already being used in other mission-critical applications for managing EMC, an

  7. Characterization of the intermediate-range order in new superionic conducting AgI-Ag2S-AgPO3 glasses by neutron diffraction

    NASA Astrophysics Data System (ADS)

    Kartini, E.; Kennedy, S. J.; Itoh, K.; Fukunaga, T.; Suminta, S.; Kamiyama, T.

    Superionic conducting glasses are of considerable technological interest because of their use in batteries, sensors, and displays. We have investigated the new ternary systems AgI-Ag2S-AgPO3 where the ratio AgI:Ag2S is 1:1. The system (AgI)x(Ag2S)x(AgPO3)1-2x, for a AgI+Ag2S fraction less than 82mol%, yields glasses. We have used a neutron-diffraction technique to obtain the total scattering structure factor S(Q) of this system at room temperature by using the HIT spectrometer at the High Energy Accelerator (KEK), Tsukuba, Japan. As for AgI-AgPO3 glasses, S(Q) shows a peak at anomalously low Q in the range from 0.6 to 0.9 Å-1. This peak is not observed in the corresponding glass Ag2S-AgPO3 or pure AgPO3. The peak depends strongly on the dopant salt. Its intensity increases as the amount of (AgI+Ag2S) increases and its position shifts to lower Q, while the number density of the glasses decreases with x. This peak can be associated with an intermediate structure of particles lying inside a continuous host with the characteristic length between 5 and 10 Å [1].

  8. The IPNS second harmonic RF upgrade.

    SciTech Connect

    Middendorf, M. E.; Brumwell, F. R.; Dooling, J. C.; Horan, D.; Kustom, R. L.; Lien, M. K.; McMichael, G. E.; Moser, M. R.; Nassiri, A.; Wang, S.; Accelerator Systems Division

    2008-01-01

    The intense pulsed neutron source (IPNS) rapid cycling synchrotron (RCS) is used to accelerate protons from 50 MeV to 450 MeV, at a repetition rate of 30 Hz. The original ring design included two identical rf systems, each consisting of an accelerating cavity, cavity bias supply, power amplifiers and low-level analog electronics. The original cavities are located 180 degrees apart in the ring and provide a total peak accelerating voltage of {approx}21 kV over the 2.21-MHz to 5.14-MHz revolution frequency sweep. A third rf system has been constructed and installed in the RCS. The third rf system is capable of operating at the fundamental revolution frequency for the entire acceleration cycle, providing an additional peak accelerating voltage of up to {approx}11 kV, or at the second harmonic of the revolution frequency for the first {approx}4 ms of the acceleration cycle, providing an additional peak voltage of up to {approx}11 kV for bunch shape control. We describe here the hardware implementation and operation to date of the third rf cavity in the second harmonic mode.

  9. RF Modal Quantity Gaging

    NASA Technical Reports Server (NTRS)

    Vanleuven, K.

    1989-01-01

    The primary objective is to provide a concept of a radio frequency (RF) modal resonance technique which is being investigated as a method for gaging the quantities of subcritical cryogenic propellants in metallic tanks. Of special interest are the potential applications of the technique to microgravity propellant gaging situations. The results of concept testing using cryogenic oxygen, hydrogen, and nitrogen, as well as paraffin simulations of microgravity fluid orientations, are reported. These test results were positive and showed that the gaging concept was viable.

  10. RF current sensor

    DOEpatents

    Moore, James A.; Sparks, Dennis O.

    1998-11-10

    An RF sensor having a novel current sensing probe and a voltage sensing probe to measure voltage and current. The current sensor is disposed in a transmission line to link all of the flux generated by the flowing current in order to obtain an accurate measurement. The voltage sensor is a flat plate which operates as a capacitive plate to sense voltage on a center conductor of the transmission line, in which the measured voltage is obtained across a resistance leg of a R-C differentiator circuit formed by the characteristic impedance of a connecting transmission line and a capacitance of the plate, which is positioned proximal to the center conductor.

  11. Ion source with external RF antenna

    DOEpatents

    Leung, Ka-Ngo; Ji, Qing; Wilde, Stephen

    2005-12-13

    A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source.

  12. Fabrication of porous silicon nanowires by MACE method in HF/H2O2/AgNO3 system at room temperature.

    PubMed

    Li, Shaoyuan; Ma, Wenhui; Zhou, Yang; Chen, Xiuhua; Xiao, Yongyin; Ma, Mingyu; Zhu, Wenjie; Wei, Feng

    2014-01-01

    In this paper, the moderately and lightly doped porous silicon nanowires (PSiNWs) were fabricated by the 'one-pot procedure' metal-assisted chemical etching (MACE) method in the HF/H2O2/AgNO3 system at room temperature. The effects of H2O2 concentration on the nanostructure of silicon nanowires (SiNWs) were investigated. The experimental results indicate that porous structure can be introduced by the addition of H2O2 and the pore structure could be controlled by adjusting the concentration of H2O2. The H2O2 species replaces Ag(+) as the oxidant and the Ag nanoparticles work as catalyst during the etching. And the concentration of H2O2 influences the nucleation and motility of Ag particles, which leads to formation of different porous structure within the nanowires. A mechanism based on the lateral etching which is catalyzed by Ag particles under the motivation by H2O2 reduction is proposed to explain the PSiNWs formation.

  13. Fabrication of porous silicon nanowires by MACE method in HF/H2O2/AgNO3 system at room temperature

    PubMed Central

    2014-01-01

    In this paper, the moderately and lightly doped porous silicon nanowires (PSiNWs) were fabricated by the ‘one-pot procedure’ metal-assisted chemical etching (MACE) method in the HF/H2O2/AgNO3 system at room temperature. The effects of H2O2 concentration on the nanostructure of silicon nanowires (SiNWs) were investigated. The experimental results indicate that porous structure can be introduced by the addition of H2O2 and the pore structure could be controlled by adjusting the concentration of H2O2. The H2O2 species replaces Ag+ as the oxidant and the Ag nanoparticles work as catalyst during the etching. And the concentration of H2O2 influences the nucleation and motility of Ag particles, which leads to formation of different porous structure within the nanowires. A mechanism based on the lateral etching which is catalyzed by Ag particles under the motivation by H2O2 reduction is proposed to explain the PSiNWs formation. PMID:24910568

  14. Glancing angle RF sheaths

    NASA Astrophysics Data System (ADS)

    D'Ippolito, D. A.; Myra, J. R.

    2013-10-01

    RF sheaths occur in tokamaks when ICRF waves encounter conducting boundaries. The sheath plays an important role in determining the efficiency of ICRF heating, the impurity influxes from the edge plasma, and the plasma-facing component damage. An important parameter in sheath theory is the angle θ between the equilibrium B field and the wall. Recent work with 1D and 2D sheath models has shown that the rapid variation of θ around a typical limiter can lead to enhanced sheath potentials and localized power deposition (hot spots) when the B field is near glancing incidence. The physics model used to obtain these results does not include some glancing-angle effects, e.g. possible modification of the angular dependence of the Child-Langmuir law and the role of the magnetic pre-sheath. Here, we report on calculations which explore these effects, with the goal of improving the fidelity of the rf sheath BC used in analytical and numerical calculations. Work supported by US DOE grants DE-FC02-05ER54823 and DE-FG02-97ER54392.

  15. The MUCOOL RF Program

    SciTech Connect

    Norem, J.; Bross, A.; Moretti, A.; Norris, B.; Qian, Z.; Torun, Y.; Rimmer, R.; Li, D.; Virostek, S.; Zisman, M.; Sandstrom, R.; /Geneva U.

    2006-06-26

    Efficient muon cooling requires high RF gradients in the presence of high (3T) solenoidal fields. The Muon Ionization Cooling Experiment (MICE) also requires that the x-ray production from these cavities is low, in order to minimize backgrounds in the particle detectors that must be located near the cavities. These cavities require thin Be windows to ensure the highest fields on the beam axis. In order to develop these cavities, the MUCOOL RF Program was started about 6 years ago. Initial measurements were made on a six-cell cavity and a single-cell pillbox, both operating at 805 MHz. We have now begun measurements of a 201 MHz pillbox cavity. This program has led to new techniques to look at dark currents, a new model for breakdown and a general model of cavity performance based on surface damage. The experimental program includes studies of thin Be windows, conditioning, dark current production from different materials, magnetic-field effects and breakdown.

  16. An Efficient RF Source for Jlab

    SciTech Connect

    Neubauer, M.; Dudas, A.; Rimmer, Robert A.; Wang, Haipeng

    2013-12-01

    We propose the development of a highly reliable high efficiency RF source for JLAB with a lower lifetime cost operating at 80% efficiency with system operating costs of about 0.7M$/year for the 6 GeV machine. The design of the RF source will be based upon two injection locked magnetrons in a novel combining architecture for amplitude modulation and a cross field amplifier (CFA) as an output tube for the 12 GeV upgrade. A cost analysis including efficiency and reliability will be performed to determine the optimum system architecture. Several different system architectures will be designed and evaluated for a dual injection locked magnetron source using novel combining techniques and possibly a CFA as the output tube. A paper design for the 1497 MHz magnetron system will be completed. The optimum system architecture with all relevant specifications will be completed so that a prototype can be built.

  17. RF wave propagation and scattering in turbulent tokamak plasmas

    SciTech Connect

    Horton, W. Michoski, C.; Peysson, Y.; Decker, J.

    2015-12-10

    Drift wave turbulence driven by the steep electron and ion temperature gradients in H-mode divertor tokamaks produce scattering of the RF waves used for heating and current drive. The X-ray emission spectra produced by the fast electrons require the turbulence broaden RF wave spectrum. Both the 5 GHz Lower Hybrid waves and the 170 GHz electron cyclotron [EC] RF waves experience scattering and diffraction by the electron density fluctuations. With strong LHCD there are bifurcations in the coupled turbulent transport dynamics giving improved steady-state confinement states. The stochastic scattering of the RF rays makes the prediction of the distribution of the rays and the associated particle heating a statistical problem. Thus, we introduce a Fokker-Planck equation for the probably density of the RF rays. The general frame work of the coupled system of coupled high frequency current driving rays with the low-frequency turbulent transport determines the profiles of the plasma density and temperatures.

  18. NQR detection of explosive simulants using RF atomic magnetometers

    NASA Astrophysics Data System (ADS)

    Monti, Mark C.; Alexson, Dimitri A.; Okamitsu, Jeffrey K.

    2016-05-01

    Nuclear Quadrupole Resonance (NQR) is a highly selective spectroscopic method that can be used to detect and identify a number of chemicals of interest to the defense, national security, and law enforcement community. In the past, there have been several documented attempts to utilize NQR to detect nitrogen bearing explosives using induction sensors to detect the NQR RF signatures. We present here our work on the NQR detection of explosive simulants using optically pumped RF atomic magnetometers. RF atomic magnetometers can provide an order of magnitude (or more) improvement in sensitivity versus induction sensors and can enable mitigation of RF interference, which has classically has been a problem for conventional NQR using induction sensors. We present the theory of operation of optically pumped RF atomic magnetometers along with the result of laboratory work on the detection of explosive simulant material. An outline of ongoing work will also be presented along with a path for a fieldable detection system.

  19. RF wave propagation and scattering in turbulent tokamak plasmas

    NASA Astrophysics Data System (ADS)

    Horton, W.; Michoski, C.; Peysson, Y.; Decker, J.

    2015-12-01

    Drift wave turbulence driven by the steep electron and ion temperature gradients in H-mode divertor tokamaks produce scattering of the RF waves used for heating and current drive. The X-ray emission spectra produced by the fast electrons require the turbulence broaden RF wave spectrum. Both the 5 GHz Lower Hybrid waves and the 170 GHz electron cyclotron [EC] RF waves experience scattering and diffraction by the electron density fluctuations. With strong LHCD there are bifurcations in the coupled turbulent transport dynamics giving improved steady-state confinement states. The stochastic scattering of the RF rays makes the prediction of the distribution of the rays and the associated particle heating a statistical problem. Thus, we introduce a Fokker-Planck equation for the probably density of the RF rays. The general frame work of the coupled system of coupled high frequency current driving rays with the low-frequency turbulent transport determines the profiles of the plasma density and temperatures.

  20. Schottky or Ohmic metal-semiconductor contact: influence on photocatalytic efficiency of Ag/ZnO and Pt/ZnO model systems.

    PubMed

    Yan, Fengpo; Wang, Yonghao; Zhang, Jiye; Lin, Zhang; Zheng, Jinsheng; Huang, Feng

    2014-01-01

    The relationship between the contact type in metal-semiconductor junctions and their photocatalytic efficiencies is investigated. Two metal-semiconductor junctions, silver on zinc oxide (Ag/ZnO) and platinum on zinc oxide (Pt/ZnO) serve as model system for Ohmic and Schottky metal-semiconductor contact, respectively. Ag/ZnO, with Ohmic contact, exhibits a higher photocatalytic efficiency than Pt/ZnO, with Schottky contact. The direction of electric fields within the semiconductor is found to play a crucial role in the separation of photogenerated charges, and thus strongly influences the photocatalytic efficiency.

  1. A Micromechanical RF Channelizer

    NASA Astrophysics Data System (ADS)

    Akgul, Mehmet

    The power consumption of a radio generally goes as the number and strength of the RF signals it must process. In particular, a radio receiver would consume much less power if the signal presented to its electronics contained only the desired signal in a tiny percent bandwidth frequency channel, rather than the typical mix of signals containing unwanted energy outside the desired channel. Unfortunately, a lack of filters capable of selecting single channel bandwidths at RF forces the front-ends of contemporary receivers to accept unwanted signals, and thus, to operate with sub-optimal efficiency. This dissertation focuses on the degree to which capacitive-gap transduced micromechanical resonators can achieve the aforementioned RF channel-selecting filters. It aims to first show theoretically that with appropriate scaling capacitive-gap transducers are strong enough to meet the needed coupling requirements; and second, to fully detail an architecture and design procedure needed to realize said filters. Finally, this dissertation provides an actual experimentally demonstrated RF channel-select filter designed using the developed procedures and confirming theoretical predictions. Specifically, this dissertation introduces four methods that make possible the design and fabrication of RF channel-select filters. The first of these introduces a small-signal equivalent circuit for parallel-plate capacitive-gap transduced micromechanical resonators that employs negative capacitance to model the dependence of resonance frequency on electrical stiffness in a way that facilitates the analysis of micromechanical circuits loaded with arbitrary electrical impedances. The new circuit model not only correctly predicts the dependence of electrical stiffness on the impedances loading the input and output electrodes of parallel-plate capacitive-gap transduced micromechanical device, but does so in a visually intuitive way that identifies current drive as most appropriate for

  2. RF FEL for power beaming

    NASA Astrophysics Data System (ADS)

    Burke, Robert

    The laser device components associated with operating a radio frequency-free electron laser (RF-FEL) for beaming power from Earth were designed and tested. Analysis of the power beaming system requirements reveals that the FEL, identified by NASA as the laser of choice, is the major subsystem requiring demonstration before proceeding further in proving the efficacy of laser power beaming. Rocketdyne has identified a series of low cost, low risk demonstrations which proceed sequentially, as follows: (1) a 1 kW proof-of-principle demonstration; (2) a 150 kW demonstration of beaming power to a satellite; and (3) a MW class demonstration of Earth to lunar surface power transmission. This sequence of events can be completed in 5.5 years at a cost of $188M, with key milestones each year.

  3. Determination of standard thermodynamic properties of daubreelite (FeCr2S4) in the system Ag-Cr-Fe-S by the solid state galvanic cells method

    NASA Astrophysics Data System (ADS)

    Osadchii, Evgeniy; Voronin, Mikhail; Osadchii, Valentin

    2014-05-01

    Daubreelite is a common mineral in enstatite chondrites, but its thermodynamic properties have not been studied. This greatly complicates the study of the physico - chemical parameters of enstatite chondrites formation in their parent bodies. Analysis of the quaternary system Ag-Cr-Fe-S showed that at temperatures below 423 K can be stable phase association Ag2S + Cr2S3 + FeS2 + FeCr2S4, potential silver which can be defined in a completely solid state galvanic cell: (-) Pt | Ag | RbAg4I5 | Ag2S, Cr2S3, FeS2, FeCr2S4 | Pt (+), with a RbAg4I5 as a solid electrolyte with a specific conductivity of Ag+ ion. The overall potential forming process in the cell corresponds to a chemical reaction: 2Ag + Cr2S3 + FeS2 = Ag2S + FeCr2S4 Gibbs energy of this reaction is associated with the electromotive force of galvanic cells by fundamental equation of thermodynamics ΔrG =-nFE, where n = 2 - the number of electrons in the electrochemical process, F = 96485 C•mol-1 - Faraday constant, and E-electromotive force (emf) of galvanic cell in volts. Temperature dependence of the emf was determined in an electrochemical cell, a device which is described in detail in the works Osadchii and Chareev (2006), and Osadchii and Echmaeva (2007). The results were approximated by a linear dependence of E(T), which corresponds to the condition ΔrCp constant and equal to zero: E(mV)=76.32+0.2296•T, 339

  4. An RF amplifier for ICRF studies in the LAPD

    NASA Astrophysics Data System (ADS)

    Martin, M. J.; Pribyl, P.; Gekelman, W.; Lucky, Z.

    2015-12-01

    An RF amplifier system was designed and is under construction at the UCLA Basic Plasma Science Facility. The system is designed to output 200 kW peak RMS power at 1% duty cycle with a 1 Hz rep rate at frequencies of 2-6 MHz. This paper describes the RF amplifier system with preliminary benchmarks. Current design challenges and future work are discussed.

  5. Attitude Ground System (AGS) for the Magnetospheric Multi-Scale (MMS) Mission

    NASA Technical Reports Server (NTRS)

    Raymond, Juan C.; Sedlak, Joseph E.; Vint, Babak

    2015-01-01

    MMS Overview Recall from Conrads presentation earlier today MMS launch: March 13, 2015 on an Atlas V from Space Launch Complex 40, Cape Canaveral, Florida MMS Observatory Separation: five minute intervals spinning at 3 rpm approximately 1.5 hours after launch MMS Science Goals: study magnetospheric plasma physics and understand the processes that cause power grids, communication disruptions and Aurora formation Mission: 4 identical spacecraft in tetrahedral formation with variable size1.2 x 12 RE in Phase 1, with apogee on dayside to observe bow shock1.2 x 25 RE in Phase 2, with apogee on night side to observe magneto tail Challenges Tight attitude control box, orbit and formation maintenance requirements Maneuvers on thrusters every two weeks Delta-H Spin axis direction and spin rate maintenance Delta-V Orbit and Formation maintenance Mission phase transitions AGS support Smart targeting prediction of Spin-Axis attitude in the presence of environmental torques to stay within the science attitude Determination of the spacecraft attitude and spin rate (sensitive to knowledge of inertia tensor)Calibrations to improve attitude determination results and improve orbit maneuvers Mass properties (Center of Mass, and inertia tensor for nutation and coning) Accelerometer bias (sensitive to the accuracy of the rate estimates) Sensor alignments.

  6. Integrated RF modules for cooperative UGV/UAV tandems

    NASA Astrophysics Data System (ADS)

    Mitra, Atindra K.; Westbrook, Lamar; Corgan, Johnathan; Young, Sean; Nagar, Jogender; Bariagaber, Tedros

    2008-04-01

    This paper addresses a number of design issues that are associated with integrating lightweight and low-cost RF (Radio Frequency) sensors onto small UGV's (Unmanned Ground Vehicles) and UAV's (Unmanned Aerial Vehicles). Modularintegrated RF sub-systems functions that are discussed include lightweight software programmable radar (or software radar) using COTS software radio components and compact microstrip antenna design concepts for low-frequency surface penetration radars. A discussion on the potential for implementing lightweight multi-function RF systems as well as a discussion on novel futuristic concepts that explore the limits of sensor/platform integration is included.

  7. RF MEMS Based Reconfigurable Antennas

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2004-01-01

    The presentation will first of all address the advantages of RF MEMS circuit in antenna applications and also the need for electronically reconfigurable antennas. Next, discuss some of the recent examples of RF MEMS based reconfigurable microstrip antennas. Finally, conclude the talk with a summary of MEMS antenna performance.

  8. Photostimulated Luminescence and Dynamics of AgI and Ag Nanoclusters in Zeolites

    SciTech Connect

    Chen, Wei; Joly, Alan G.; Roark, Joel

    2002-06-15

    The photoluminescence and photostimulated luminescence of Ag and AgI nanoclusters formed in zeolite-Y are studied using fluorescence spectroscopy. The photoluminescence spectra of AgI nanoclusters show emission from both AgI and Ag nanoclusters, while the in the photostimulated luminescence, only the emission of Ag clusters is observed. While the photoluminescence from both Ag and AgI particles displays both sub-nanosecond and microsecond lifetimes, the emission from photostimulated luminescence shows very short, picosecond lifetimes. A model which ascribes the photostimulated luminescence to recombination of electrons trapped in the zeolite with Ag in close proximity to the trap site is proposed. The appearance of strong photostimulated luminescence with short decays in these systems demonstrates that nanoparticles have potential for digital storage and medical radiology applications.

  9. NSLS-II RF BEAM POSITION MONITOR

    SciTech Connect

    Vetter, K.; Della Penna, A. J.; DeLong, J.; Kosciuk, B.; Mead, J.; Pinayev, I.; Singh, O.; Tian, Y.; Ha, K.; Portmann, G.; Sebek J.

    2011-03-28

    An internal R&D program has been undertaken at BNL to develop a sub-micron RF Beam Position Monitor (BPM) for the NSLS-II 3rd generation light source that is currently under construction. The BPM R&D program started in August 2009. Successful beam tests were conducted 15 months from the start of the program. The NSLS-II RF BPM has been designed to meet all requirements for the NSLS-II Injection system and Storage Ring. Housing of the RF BPM's in +-0.1 C thermally controlled racks provide sub-micron stabilization without active correction. An active pilot-tone has been incorporated to aid long-term (8hr min) stabilization to 200nm RMS. The development of a sub-micron BPM for the NSLS-II has successfully demonstrated performance and stability. Pilot Tone calibration combiner and RF synthesizer has been implemented and algorithm development is underway. The program is currently on schedule to start production development of 60 Injection BPM's starting in the Fall of 2011. The production of {approx}250 Storage Ring BPM's will overlap the Injection schedule.

  10. RF Design of the LCLS Gun

    SciTech Connect

    Limborg-Deprey, C

    2010-12-13

    Final dimensions for the LCLS RF gun are described. This gun, referred to as the LCLS gun, is a modified version of the UCLA/BNL/SLAC 1.6 cell S-Band RF gun [1], referred to as the prototype gun. The changes include a larger mode separation (15 MHz for the LCLS gun vs. 3.5 MHz for the prototype gun), a larger radius at the iris between the 2 cells, a reduced surface field on the curvature of the iris between the two cells, Z power coupling, increased cooling channels for operation at 120 Hz, dual rf feed, deformation tuning of the full cell, and field probes in both cells. Temporal shaping of the klystron pulse, to reduce the average power dissipated in the gun, has also been adopted. By increasing the mode separation, the amplitude of the 0-mode electric field on the cathode decreases from 10% of the peak on axis field for the prototype gun to less than 3% for the LCLS gun for the steady state fields. Beam performance is improved as shown by the PARMELA simulations. The gun should be designed to accept a future load lock system. Modifications follow the recommendations of our RF review committee [2]. Files and reference documents are compiled in Section IV.

  11. Image reconstructions with the rotating RF coil

    NASA Astrophysics Data System (ADS)

    Trakic, A.; Wang, H.; Weber, E.; Li, B. K.; Poole, M.; Liu, F.; Crozier, S.

    2009-12-01

    Recent studies have shown that rotating a single RF transceive coil (RRFC) provides a uniform coverage of the object and brings a number of hardware advantages (i.e. requires only one RF channel, averts coil-coil coupling interactions and facilitates large-scale multi-nuclear imaging). Motion of the RF coil sensitivity profile however violates the standard Fourier Transform definition of a time-invariant signal, and the images reconstructed in this conventional manner can be degraded by ghosting artifacts. To overcome this problem, this paper presents Time Division Multiplexed — Sensitivity Encoding (TDM-SENSE), as a new image reconstruction scheme that exploits the rotation of the RF coil sensitivity profile to facilitate ghost-free image reconstructions and reductions in image acquisition time. A transceive RRFC system for head imaging at 2 Tesla was constructed and applied in a number of in vivo experiments. In this initial study, alias-free head images were obtained in half the usual scan time. It is hoped that new sequences and methods will be developed by taking advantage of coil motion.

  12. Advanced RF power sources for linacs

    SciTech Connect

    Wilson, P.B.

    1996-10-01

    In order to maintain a reasonable over-all length at high center-of-mass energy, the main linac of an electron-positron linear collider must operate at a high accelerating gradient. For copper (non-superconducting) accelerator structures, this implies a high peak power per unit length and a high peak power per RF source, assuming a limited number of discrete sources are used. To provide this power, a number of devices are currently under active development or conceptual consideration: conventional klystrons with multi-cavity output structures, gyroklystrons, magnicons, sheet-beam klystrons, multiple-beam klystrons and amplifiers based on the FEL principle. To enhance the peak power produced by an rf source, the SLED rf pulse compression scheme is currently in use on existing linacs, and new compression methods that produce a flatter output pulse are being considered for future linear colliders. This paper covers the present status and future outlook for the more important rf power sources and pulse compression systems. It should be noted that high gradient electron linacs have applications in addition to high-energy linear colliders; they can, for example, serve as compact injectors for FEL`s and storage rings.

  13. AGS II

    SciTech Connect

    Palmer, R.B.

    1984-01-01

    Interest in rare K decays, neutrino oscillations and other fields have generated an increasing demand for running, and improved intensity and duty cycle, at the AGS. Current projects include acceleration of polarized protons and light ions (up to mass 32). Future plans are for a booster to increase intensity and allow heavy ions (up to mass 200), and a stretcher to give 100% duty cycle. A later upgrade could yield an average current of 32 ..mu.. amps. 6 figures, 2 tables.

  14. Thermometric consideration for RF and microwave research in food engineering.

    PubMed

    Ofoli, R Y

    1986-01-01

    A review of thermometric methods for the processing of food materials at RF and microwave frequencies is presented. Some areas of needed food engineering research are discussed, as well as factors of importance in the selection of temperature monitoring systems.

  15. Electro-optic microdisk RF-wireless receiver

    NASA Astrophysics Data System (ADS)

    Hossein-Zadeh, Mani

    A self-homodyne photonic receiver for transmitted carrier wireless links is demonstrated. The key innovations in this photonic RF-receiver are the design and implementation of a resonant LiNbO3 microdisk electro-optic modulator and novel RF down-conversion techniques that exploit the sensitivity of the microdisk for efficient RF down-conversion in the optical domain. By careful RF and optical design, simultaneous photonic and RF resonance is achieved in a LiNbO3 microdisk modulator resulting in a sensitivity of -80 dBm at 14.6 GHz. Two photonic RF down-conversion techniques are proposed to extract the baseband information from a RF signal that has a transmitted carrier modulation format. In the first approach we use an optical filter to modify the optical output spectrum of the microdisk modulator. Photodetection of the subsequent optical signal generates the baseband photocurrent. In the second technique the RF carrier and sidebands are mixed through nonlinear optical modulation in the microdisk and the down-converted signal is detected using a photodetector. In both cases the bandwidth of the photodetector and electronic circuitry are limited to that of the baseband signal. Receiver operation is demonstrated by demodulating up to 100 Mb/s digital data from a 14.6 GHz RF carrier frequency. Power efficiency, small volume, light weight and elimination of high-speed electronic components are the main specifications of the photonic RF-receiver that make it useful for applications like wireless LANs, fiber-feed backbone networks or video distribution systems.

  16. LED Die-Bonded on the Ag/Cu Substrate by a Sn-BiZn-Sn Bonding System

    NASA Astrophysics Data System (ADS)

    Tang, Y. K.; Hsu, Y. C.; Lin, E. J.; Hu, Y. J.; Liu, C. Y.

    2016-08-01

    In this study, light emitting diode (LED) chips were die-bonded on a Ag/Cu substrate by a Sn-BixZn-Sn bonding system. A high die-bonding strength is successfully achieved by using a Sn-BixZn-Sn ternary system. At the bonding interface, there is observed a Bi-segregation phenomenon. This Bi-segregation phenomenon solves the problems of the brittle layer-type Bi at the joint interface. Our shear test results show that the bonding interface with Bi-segregation enhances the shear strength of the LED die-bonding joints. The Bi-0.3Zn and Bi-0.5Zn die-bonding cases have the best shear strength among all die-bonding systems. In addition, we investigate the atomic depth profile of the deposited Bi-xZn layer by evaporating Bi-xZn E-gun alloy sources. The initial Zn content of the deposited Bi-Zn alloy layers are much higher than the average Zn content in the deposited Bi-Zn layers.

  17. Shielding for thermoacoustic tomography with RF excitation

    NASA Astrophysics Data System (ADS)

    Mitchell, M.; Becker, G.; Dey, P.; Generotzky, J.; Patch, S. K.

    2008-02-01

    Radiofrequency (RF) pulses used to generate thermoacoustic computerized tomography (TCT) signal couple directly into the pulser-receiver and oscilloscope, swamping true TCT signal. We use a standard RF enclosure housing both RF amplifier and object being imaged. This is similar to RF shielding of magnetic resonance imaging (MRI) suites and protects electronics outside from stray RF. Unlike MRI, TCT receivers are ultrasound transducers, which must also be shielded from RF. A transducer housing that simultaneously shields RF and permits acoustic transmission was developed specifically for TCT. We compare TCT signals measured with and without RF shielding.

  18. TiO2 nanotube composite layers as delivery system for ZnO and Ag nanoparticles - an unexpected overdose effect decreasing their antibacterial efficacy.

    PubMed

    Roguska, A; Belcarz, A; Pisarek, M; Ginalska, G; Lewandowska, M

    2015-06-01

    Enhancement of biocompatibility and antibacterial properties of implant materials is potentially beneficial for their practical value. Therefore, the use of metallic and metallic oxide nanoparticles as antimicrobial coatings components which induce minimized antibacterial resistance receives currently particular attention. In this work, TiO2 nanotubes layers loaded with ZnO and Ag nanoparticles were designed for biomedical coatings and delivery systems and evaluated for antimicrobial activity. TiO2 nanotubes themselves exhibited considerable and diameter-dependent antibacterial activity against planktonic Staphylococcus epidermidis cells but favored bacterial adhesion. Loading of nanotubes with moderate amount of ZnO nanoparticles significantly diminished S. epidermidis cell adhesion and viability just after 1.5h contact with modified surfaces. However, an increase of loaded ZnO amount unexpectedly altered the structure of nanoparticle-nanolayer, caused partial closure of nanotube interior and significantly reduced ZnO solubility and antibacterial efficacy. Co-deposition of Ag nanoparticles enhanced the antibacterial properties of synthesized coatings. However, the increase of ZnO quantity on Ag nanoparticles co-deposited surfaces favored the adhesion of bacterial cells. Thus, ZnO/Ag/TiO2 nanotube composite layers may be promising delivery systems for combating post-operative infections in hard tissue replacement procedures. However, the amount of loaded antibacterial agents must be carefully balanced to avoid the overdose and reduced efficacy.

  19. TiO2 nanotube composite layers as delivery system for ZnO and Ag nanoparticles - an unexpected overdose effect decreasing their antibacterial efficacy.

    PubMed

    Roguska, A; Belcarz, A; Pisarek, M; Ginalska, G; Lewandowska, M

    2015-06-01

    Enhancement of biocompatibility and antibacterial properties of implant materials is potentially beneficial for their practical value. Therefore, the use of metallic and metallic oxide nanoparticles as antimicrobial coatings components which induce minimized antibacterial resistance receives currently particular attention. In this work, TiO2 nanotubes layers loaded with ZnO and Ag nanoparticles were designed for biomedical coatings and delivery systems and evaluated for antimicrobial activity. TiO2 nanotubes themselves exhibited considerable and diameter-dependent antibacterial activity against planktonic Staphylococcus epidermidis cells but favored bacterial adhesion. Loading of nanotubes with moderate amount of ZnO nanoparticles significantly diminished S. epidermidis cell adhesion and viability just after 1.5h contact with modified surfaces. However, an increase of loaded ZnO amount unexpectedly altered the structure of nanoparticle-nanolayer, caused partial closure of nanotube interior and significantly reduced ZnO solubility and antibacterial efficacy. Co-deposition of Ag nanoparticles enhanced the antibacterial properties of synthesized coatings. However, the increase of ZnO quantity on Ag nanoparticles co-deposited surfaces favored the adhesion of bacterial cells. Thus, ZnO/Ag/TiO2 nanotube composite layers may be promising delivery systems for combating post-operative infections in hard tissue replacement procedures. However, the amount of loaded antibacterial agents must be carefully balanced to avoid the overdose and reduced efficacy. PMID:25842121

  20. A Micromechanical RF Channelizer

    NASA Astrophysics Data System (ADS)

    Akgul, Mehmet

    The power consumption of a radio generally goes as the number and strength of the RF signals it must process. In particular, a radio receiver would consume much less power if the signal presented to its electronics contained only the desired signal in a tiny percent bandwidth frequency channel, rather than the typical mix of signals containing unwanted energy outside the desired channel. Unfortunately, a lack of filters capable of selecting single channel bandwidths at RF forces the front-ends of contemporary receivers to accept unwanted signals, and thus, to operate with sub-optimal efficiency. This dissertation focuses on the degree to which capacitive-gap transduced micromechanical resonators can achieve the aforementioned RF channel-selecting filters. It aims to first show theoretically that with appropriate scaling capacitive-gap transducers are strong enough to meet the needed coupling requirements; and second, to fully detail an architecture and design procedure needed to realize said filters. Finally, this dissertation provides an actual experimentally demonstrated RF channel-select filter designed using the developed procedures and confirming theoretical predictions. Specifically, this dissertation introduces four methods that make possible the design and fabrication of RF channel-select filters. The first of these introduces a small-signal equivalent circuit for parallel-plate capacitive-gap transduced micromechanical resonators that employs negative capacitance to model the dependence of resonance frequency on electrical stiffness in a way that facilitates the analysis of micromechanical circuits loaded with arbitrary electrical impedances. The new circuit model not only correctly predicts the dependence of electrical stiffness on the impedances loading the input and output electrodes of parallel-plate capacitive-gap transduced micromechanical device, but does so in a visually intuitive way that identifies current drive as most appropriate for

  1. The design for the LCLS RF photoinjector

    NASA Astrophysics Data System (ADS)

    Alley, R.; Bharadwaj, V.; Clendenin, J.; Emma, P.; Fisher, A.; Frisch, J.; Kotseroglou, T.; Miller, R. H.; Palmer, D. T.; Schmerge, J.; Sheppard, J. C.; Woodley, M.; Yeremian, A. D.; Rosenzweig, J.; Meyerhofer, D. D.; Serafini, L.

    1999-06-01

    We report on the design of the RF photoinjector of the Linac Coherent Light Source. The RF photoinjector is required to produce a single 150 MeV bunch of ˜1 nC and ˜100 A peak current at a repetition rate of 120 Hz with a normalized rms transverse emittance of ˜1 π mm-mrad. The design employs a 1.6-cell S-band RF gun with an optical spot size at the cathode of a radius of ˜1 mm and a pulse duration with an rms sigma of ˜3 ps. The peak RF field at the cathode is 150 MV/m with extraction 57° ahead of the RF peak. A solenoidal field near the cathode allows the compensation of the initial emittance growth by the end of the injection linac. Spatial and temporal shaping of the laser pulse striking the cathode will reduce the compensated emittance even further. Also, to minimize the contribution of the thermal emittance from the cathode surface, while at the same time optimizing the quantum efficiency, the laser wavelength for a Cu cathode should be tunable around 260 nm. Following the injection linac the geometric emittance simply damps linearly with energy growth. PARMELA simulations show that this design will produce the desired normalized emittance, which is about a factor of two lower than has been achieved to date in other systems. In addition to low emittance, we also aim for laser amplitude stability of 1% in the UV and a timing jitter in the electron beam of 0.5 ps rms, which will lead to less than 10% beam intensity fluctuation after the electron bunch is compressed in the main linac.

  2. RF pulse compression in the NLC test accelerator at SLAC

    NASA Astrophysics Data System (ADS)

    Lavine, Theodore L.

    1995-07-01

    At the Stanford Linear Accelerator Center (SLAC), we are designing a Next Linear Collider (NLC) with linacs powered by X-band klystrons with rf pulse compression. The design of the linac rf system is based on X-band prototypes which have been tested at high power, and on a systems-integration test—the Next Linear Collider Test Accelerator (NLCTA)—which is currently under construction at SLAC. This paper discusses some of the systems implications of rf pulse compression, and the use of pulse compression in the NLCTA, both for peak power multiplication and for controlling, by rf phase modulation, intra-pulse variations in the linac beam energy.

  3. Spectroscopy of {sup 257}Rf

    SciTech Connect

    Qian, J.; Heinz, A.; Winkler, R.; Khoo, T. L.; Janssens, R. V. F.; Peterson, D.; Seweryniak, D.; Ahmad, I.; Back, B. B.; Carpenter, M. P.; Greene, J. P.; Jiang, C. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; Robinson, A.; Savard, G.; Scott, R.; Vondrasek, R.; Wang, X.

    2009-06-15

    The isotope {sup 257}Rf was produced in the fusion-evaporation reaction {sup 208}Pb({sup 50}Ti,n){sup 257}Rf. Reaction products were separated and identified by mass. Delayed spectroscopy of {sup 257}Rf and its decay products was performed. A partial decay scheme with configuration assignments is proposed based on {alpha} hindrance factors. The excitation energy of the 1/2{sup +}[620] configuration in {sup 253}No is proposed. The energy of this 1/2{sup +} state in a series of N=151 isotones increases with nuclear charge, reflecting an increase in the N=152 gap. This gap is deduced to grow substantially from 850 to 1400 keV between Z=94 and 102. An isomeric state in {sup 257}Rf, with a half-life of 160{sub -31}{sup +42} {mu}s, was discovered by detecting internal conversion electrons followed by {alpha} decay. It is interpreted as a three-quasiparticle high-K isomer. A second group of internal conversion electrons, with a half-life of 4.1{sub -1.3}{sup +2.4} s, followed by {alpha} decay, was also observed. These events might originate from the decay of excited states in {sup 257}Lr, populated by electron-capture decay of {sup 257}Rf. Fission of {sup 257}Rf was unambiguously detected, with a branching ratio of b{sub Rf}{sup SF}=0.02{+-}0.01.

  4. Copper-based alloys, crystallographic and crystallochemical parameters of alloys in binary systems Cu-Me (Me=Co, Rh, Ir, Cu, Ag, Au, Ni, Pd, Pt)

    NASA Astrophysics Data System (ADS)

    Porobova, Svetlana; Markova, Tat'jana; Klopotov, Vladimir; Klopotov, Anatoliy; Loskutov, Oleg; Vlasov, Viktor

    2016-01-01

    The article presents the results of the analysis of phase equilibrium of ordered phases in binary systems based on copper Cu- Me (where Me - Co, Rh, Ir, Ag, Au, Ni, Pd, Pt) to find correlations of crystallochemical and crystallographic factors. It is established that the packing index in disordered solid solutions in binary systems based on copper is close to the value of 0.74 against the background of an insignificant deviation of atomic volumes from the Zen's law.

  5. RF-dressed Rydberg atoms in hollow-core fibres

    NASA Astrophysics Data System (ADS)

    Veit, C.; Epple, G.; Kübler, H.; Euser, T. G.; Russell, P. St. J.; Löw, R.

    2016-07-01

    The giant electro-optical response of Rydberg atoms manifests itself in the emergence of sidebands in the Rydberg excitation spectrum if the atom is exposed to a radio-frequency (RF) electric field. Here we report on the study of RF-dressed Rydberg atoms inside hollow-core photonic crystal fibres, a system that enables the use of low modulation voltages and offers the prospect of miniaturised vapour-based electro-optical devices. Narrow spectroscopic features caused by the RF field are observed for modulation frequencies up to 500 MHz.

  6. High field rf superconductivity: to pulse or not to pulse

    SciTech Connect

    Campisi, I.E.

    1984-10-01

    Experimental data on the behavior of superconductors under the application of rf fields of amplitude comparable to their critical fields are sporadic and not always consistent. In many cases the field level at which breakdown in superconducting rf cavities should be expected has not been clearly established. Tests conducted with very short (approx. 1 ..mu..s) rf pulses indicate that in this mode of operation fields close to the critical values can be consistently reached in superconducting cavities without breakdown. The advantages and disadvantages of the pulsed method are discussed compared to those of the more standard continuous wave (cw) systems. 60 references.

  7. Telemetry formats for the Space Station RF links

    NASA Technical Reports Server (NTRS)

    Marker, Walter

    1987-01-01

    This paper discusses the formats that have been proposed for the manned Space Station space/ground RF link. In addition to discussing the specific RF formats, the paper seeks to discuss the requirements that have caused the proposed format to exist in its current form. The paper begins by briefly discussing the historical basis for telemetry formats within NASA, and then discusses the unique requirements that the Space Station imposes, compared to traditional space probes. The paper next treats the overall requirements that must be satisfied by the Space Station communications system. Finally the paper discusses the details of the RF format and its proposed operational usage.

  8. RF breakdown experiments at SLAC

    NASA Astrophysics Data System (ADS)

    Laurent, L.; Scheitrum, G.; Vlieks, A.; Pearson, C.; Caryotakis, G.; Luhmann, N. C.

    1999-05-01

    RF breakdown is a critical issue in the conditioning of klystrons, accelerator sections, and rf components for the next linear collider (NLC), as well as other high gradient accelerators and high power microwave sources. SLAC is conducting a series of experiments using an X-band traveling wave ring to characterize the processes and trigger mechanisms associated with rf breakdown. The goal of the research is to identify materials, processes, and manufacturing methods that will increase the breakdown threshold and minimize the time required for conditioning.

  9. RF subsystem design for microwave communication receivers

    NASA Astrophysics Data System (ADS)

    Bickford, W. J.; Brodsky, W. G.

    A system review of the RF subsystems of (IFF) transponders, tropscatter receivers and SATCOM receivers is presented. The quantity potential for S-band and X-band IFF transponders establishes a baseline requirement. From this, the feasibility of a common design for these and other receivers is evaluated. Goals are established for a GaAs MMIC (monolithic microwave integrated circuit) device and related local oscillator preselector and self-test components.

  10. Microsystem packaging of an RF SAW correlator.

    SciTech Connect

    Palmer, David A.; Brocato, Robert Wesley; Studor, George F.

    2005-01-01

    An electrically programmable surface acoustic wave (SAW) correlator was recently completed from design through small scale production in support of low power space-based communications for NASA. Three different versions of this RF microsystem were built to satisfy design requirements and overcome packaging and system reliability related issues. Flip-chip packaging and conventional thick film hybrid assembly techniques are compared in the fabrication of this microsystem.

  11. Ag/AgBr/TiO2 visible light photocatalyst for destruction of azodyes and bacteria.

    PubMed

    Hu, Chun; Lan, Yongqing; Qu, Jiuhui; Hu, Xuexiang; Wang, Aimin

    2006-03-01

    Ag/AgBr/TiO2 was prepared by the deposition-precipitation method and was found to be a novel visible light driven photocatalyst. The catalyst showed high efficiency for the degradation of nonbiodegradable azodyes and the killing of Escherichia coli under visible light irradiation (lambda>420 nm). The catalyst activity was maintained effectively after successive cyclic experiments under UV or visible light irradiation without the destruction of AgBr. On the basis of the characterization of X-ray diffraction, X-ray photoelectron spectroscopy, and Auger electron spectroscopy, the surface Ag species mainly exist as Ag0 in the structure of all samples before and after reaction, and Ag0 species scavenged hVB+ and then trapped eCB- in the process of photocatalytic reaction, inhibiting the decomposition of AgBr. The studies of ESR and H2O2 formation revealed that *OH and O2*- were formed in visible light irradiated aqueous Ag/AgBr/TiO2 suspension, while there was no reactive oxygen species in the visible light irradiated Ag0/TiO2 system. The results indicate that AgBr is the main photoactive species for the destruction of azodyes and bacteria under visible light. In addition, the bactericidal efficiency and killing mechanism of Ag/AgBr/TiO2 under visible light irradiation are illustrated and discussed. PMID:16509698

  12. Unbalanced field RF electron gun

    SciTech Connect

    Hofler, Alicia

    2013-11-12

    A design for an RF electron gun having a gun cavity utilizing an unbalanced electric field arrangement. Essentially, the electric field in the first (partial) cell has higher field strength than the electric field in the second (full) cell of the electron gun. The accompanying method discloses the use of the unbalanced field arrangement in the operation of an RF electron gun in order to accelerate an electron beam.

  13. [Thermal expansion of Au-Pd-Ag system alloys. Casting stress and deformation of addition of Sn and In].

    PubMed

    Ohkuma, K

    1989-03-01

    To study the dimensional changes due to the release of casting stress in metal-ceramic alloys, a wheel-like pattern in which casting stress is liable to occur and rod- and barrel-like wax patterns in which the likelihood of such stress is low, were investigated with a phosphate-bonded investment compound. Furthermore, simultaneous casting was done using Au-Pd-Ag system alloys, 21 types of mother alloys and alloys with tin or indium or both, and accurate determinations of the thermal expansion rate with increased or decreased temperature were carried out. The results obtained were as follows. The mean thermal expansion rates of the mother alloys and the alloys with tin and indium upon increase and decrease of temperature were lowest for the large wheel-like pattern, followed by the small wheel-like pattern, rod-like pattern and barrel-like pattern, in that order. The mean thermal expansion rates of the mother alloys and the alloys with tin or indium or both were decreased when the palladium content was increased, but tended to increase when the silver content was higher. Gold had no influence on the thermal expansion rate. When the temperature decreased, the complex addition of tin and indium provided alloys showing only a slight deformation. PMID:2690394

  14. The chemiluminescence determination of 2-chloroethyl ethyl sulfide using luminol-AgNO3-silver nanoparticles system

    NASA Astrophysics Data System (ADS)

    Maddah, Bozorgmehr; Shamsi, Javad; Barsang, Mehran Jam; Rahimi-Nasrabadi, Mehdi

    2015-05-01

    A highly sensitive chemiluminescence (CL) method for the determination of 2-chloroethyl ethyl sulfide (2-CEES) was presented. It was found that 2-chloroethyl ethyl sulfide (2-CEES) could inhibit the CL of the luminol-AgNO3 system in the presence of silver nanoparticles in alkaline solution, which made it applicable for determination of 2-CEES. The presented method is simple, convenient, rapid and sensitive. Under the optimized conditions, the calibration curve was linear in the range of 0.0001-1 ng mL-1, with the correlation coefficient of 0.992; while the limit of detection (LOD), based on signal-to-noise ratio (S/N) of 3, was 6 × 10-6 ng mL-1. Also, the relative standard deviation (RSD, n = 5) for determination of 2-CEES (0.50 ng mL-1) was 3.1%. The method was successfully applied for the determination of 2-CEES in environmental aqueous samples.

  15. The chemiluminescence determination of 2-chloroethyl ethyl sulfide using luminol-AgNO3-silver nanoparticles system.

    PubMed

    Maddah, Bozorgmehr; Shamsi, Javad; Barsang, Mehran Jam; Rahimi-Nasrabadi, Mehdi

    2015-05-01

    A highly sensitive chemiluminescence (CL) method for the determination of 2-chloroethyl ethyl sulfide (2-CEES) was presented. It was found that 2-chloroethyl ethyl sulfide (2-CEES) could inhibit the CL of the luminol-AgNO3 system in the presence of silver nanoparticles in alkaline solution, which made it applicable for determination of 2-CEES. The presented method is simple, convenient, rapid and sensitive. Under the optimized conditions, the calibration curve was linear in the range of 0.0001-1ngmL(-1), with the correlation coefficient of 0.992; while the limit of detection (LOD), based on signal-to-noise ratio (S/N) of 3, was 6×10(-6)ngmL(-1). Also, the relative standard deviation (RSD, n=5) for determination of 2-CEES (0.50ngmL(-1)) was 3.1%. The method was successfully applied for the determination of 2-CEES in environmental aqueous samples. PMID:25703367

  16. The AgESGUI geospatial simulation system for environmental model application and evaluation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Practical decision making in spatially-distributed environmental assessment and management is increasingly being based on environmental process-based models linked to geographical information systems (GIS). Furthermore, powerful computers and Internet-accessible assessment tools are providing much g...

  17. Rf-driver linear colliders

    SciTech Connect

    Wilson, P.B.

    1987-05-01

    The next generation of linear collider after the SLC (Stanford Linear Collider) will probably have an energy in the range 300 GeV-1 TeV per linac. A number of exotic accelerating schemes, such as laser and plasma acceleration, have been proposed for linear colliders of the far future. However, the technology which is most mature and which could lead to a collider in the above energy range in the relatively near future is the rf-driven linac, in which externally produced rf is fed into a more or less conventional metallic accelerating structure. Two basic technologies have been proposed for producing the required high peak rf power: discrete microwave power sources, and various two-beam acceleration schemes in which the rf is produced by a high current driving beam running parallel to the main accelerator. The current status of experimental and analytic work on both the discrete source and the two-beam methods for producing rf is discussed. The implications of beam-beam related effects (luminosity, disruption and beamstrahlung) for the design of rf-driven colliders are also considered.

  18. The cardiovascular response to the AGS

    NASA Technical Reports Server (NTRS)

    Cardus, David; Mctaggart, Wesley G.

    1993-01-01

    This paper reports the preliminary results of experiments on human subjects conducted to study the cardiovascular response to various g-levels and exposure times using an artificial gravity simulator (AGS). The AGS is a short arm centrifuge consisting of a turntable, a traction system, a platform and four beds. Data collection hardware is part of the communication system. The AGS provides a steep acceleration gradient in subjects in the supine position.

  19. Investigation of the structure of a Ag/Pd/Ag( 1 1 1 ) trilayer by means of electronic spectroscopies

    NASA Astrophysics Data System (ADS)

    Dumont, J.; Ghijsen, J.; Sporken, R.

    2002-06-01

    The growth of the Ag/Pd/Ag system has been studied by X-ray photoelectron spectroscopy and low energy electron diffraction. No chemical reaction or interdiffusion was observed between the Pd and Ag layers. The growth of the Pd interlayer follows the Frank Van der Merwe mode but is not pseudomorphic on the Ag(1 1 1) substrate. The growth of the top Ag layer on the Pd interlayer is pseudomorphic and layer by layer but contains around 12% of voids.

  20. Development of 1.3GHz HTc rf SQUID

    NASA Astrophysics Data System (ADS)

    Liu, Xin-Yuan; Xie, Fei-Xiang; Meng, Shu-Chao; Dai, Yuan-Dong; Li, Zhuang-Zhi; Ma, Ping; Yang, Tao; Nie, Rui-Juan; Wang, Fu-Ren

    2004-01-01

    A new HTc rf SQUID working at around 1.3GHz has been developed to avoid electromagnetic interference such as growing mobile communication jamming. This new system works in a frequency range from 1.23 to 1.42GHz (centred at 1.3GHz), which is not occupied by commercial communication. The sensor used in the 1.3GHz rf SQUID is made of a HTc coplanar superconducting resonator and a large-area HTc superconducting film concentrator. We have achieved in the 1.3GHz HTc rf SQUID system a minimal flux noise of 2.5×10-5Phi0/(Hz)1/2 and a magnetic field sensitivity of 38fT/(Hz)1/2 in white noise range, respectively. The effective area of the concentrator fabricated on a 15×15mm2 substrate is 1.35mm2. It is shown that the 1.3GHz rf SQUID system has a high field sensitivity. Design and implementation of 1.3GHz HTc rf SQUID offers a promising direction of rf SQUID development for higher working frequency ranges.

  1. Wireless RF communication in biomedical applications

    NASA Astrophysics Data System (ADS)

    Jones, Inke; Ricciardi, Lucas; Hall, Leonard; Hansen, Hedley; Varadan, Vijay; Bertram, Chris; Maddocks, Simon; Enderling, Stefan; Saint, David; Al-Sarawi, Said; Abbott, Derek

    2008-02-01

    This paper focuses on wireless transcutaneous RF communication in biomedical applications. It discusses current technology, restrictions and applications and also illustrates possible future developments. It focuses on the application in biotelemetry where the system consists of a transmitter and a receiver with a transmission link in between. The transmitted information can either be a biopotential or a nonelectric value like arterial pressure, respiration, body temperature or pH value. In this paper the use of radio-frequency (RF) communication and identification for those applications is described. Basically, radio-frequency identification or RFID is a technology that is analogous to the working principle of magnetic barcode systems. Unlike magnetic barcodes, passive RFID can be used in extreme climatic conditions—also the tags do not need to be within close proximity of the reader. Our proposed solution is to exploit an exciting new development in making circuits on polymers without the need for battery power. This solution exploits the principle of a surface acoustic wave (SAW) device on a polymer substrate. The SAW device is a set of interdigitated conducting fingers on the polymer substrate. If an appropriate RF signal is sent to the device, the fingers act as microantennas that pick up the signal, and this energy is then converted into acoustic waves that travel across the surface of the polymer substrate. Being a flexible polymer, the acoustic waves cause stresses that can either contract or stretch the material. In our case we mainly focus on an RF controllable microvalve that could ultimately be used for fertility control.

  2. Evaluation of two new automated assays for hepatitis B virus surface antigen (HBsAg) detection: IMMULITE HBsAg and IMMULITE 2000 HBsAg.

    PubMed

    Weber, Bernard; Dengler, Thomas; Berger, Annemarie; Doerr, Hans Wilhelm; Rabenau, Holger

    2003-01-01

    In recent years the diagnostic industry has developed new automated immunoassays for the qualitative detection of hepatitis B virus (HBV) surface antigen (HBsAg) in serum and plasma samples that are performed on analyzers that permit a high-speed throughput, random access, and primary tube sampling. The aim of the present study was the evaluation of two new automated HBsAg screening assays, IMMULITE HBsAg and IMMULITE 2000 HBsAg, from Diagnostic Products Corporation. The new HBsAg assays were compared to well-established tests (Auszyme Monoclonal [overnight incubation, version B], IMx HBsAg, AxSYM HBsAg, and Prism HBsAg [all from Abbott] and Elecsys HBsAg [Roche Diagnostics]). In the evaluation were included seroconversion panels, sera from the acute and chronic phases of infection, dilution series of various HBsAg standards, HBV subtypes and S gene mutants. To challenge the specificity of the new assays, sera from HBsAg-negative blood donors, pregnant women, and dialysis and hospitalized patients and potentially cross-reactive samples were investigated. IMMULITE HBsAg and IMMULITE 2000 HBsAg, although not as sensitive as the Elecsys HBsAg assay, were equivalent to the AxSYM HBsAg assay and showed a higher sensitivity than the Auszyme Monoclonal B and IMx HBsAg systems for detection of acute infection in seroconversion panels. The specificities (100%) of both IMMULITE assays on unselected blood donors and potentially interfering samples were comparable to those of the alternative assays after repeated testing. In conclusion, the new IMMULITE HBsAg and IMMULITE 2000 HBsAg assays show a good sensitivity for HBsAg detection compared to other well-established tests. The specificity on repeatedly tested samples was equivalent to that of the alternative assays. The rapid turnaround time, primary tube sampling, and on-board dilution make it an interesting assay system for clinical laboratory diagnosis.

  3. Locking-to-unlocking system is an efficient strategy to design DNA/silver nanoclusters (AgNCs) probe for human miRNAs

    PubMed Central

    Shah, Pratik; Choi, Suk Won; Kim, Ho-jin; Cho, Seok Keun; Bhang, Yong-Joo; Ryu, Moon Young; Thulstrup, Peter Waaben; Bjerrum, Morten Jannik; Yang, Seong Wook

    2016-01-01

    MicroRNAs (miRNAs), small non-coding RNA molecules, are important biomarkers for research and medical purposes. Here, we describe the development of a fast and simple method using highly fluorescent oligonucleotide-silver nanocluster probes (DNA/AgNCs) to efficiently detect specific miRNAs. Due to the great sequence diversity of miRNAs in humans and other organisms, a uniform strategy for miRNA detection is attractive. The concept presented is an oligonucleotide-based locking-to-unlocking system that can be endowed with miRNA complementarity while maintaining the same secondary structure. The locking-to-unlocking system is based on fold-back anchored DNA templates that consist of a cytosine-rich loop for AgNCs stabilization, an miRNA recognition site and an overlap region for hairpin stabilization. When an miRNA is recognized, fluorescence in the visible region is specifically extinguished in a concentration-dependent manner. Here, the exact composition of the fold-back anchor for the locking-to-unlocking system has been systematically optimized, balancing propensity for loop-structure formation, encapsulation of emissive AgNCs and target sensitivity. It is demonstrated that the applied strategy successfully can detect a number of cancer related miRNAs in RNA extracts from human cancer cell lines. PMID:26681688

  4. Recent Progress of RF Cavity Study at Mucool Test Area

    SciTech Connect

    Yonehara, Katsuya; /Fermilab

    2011-12-02

    Summar of presentation is: (1) MTA is a multi task working space to investigate RF cavities for R&D of muon beam cooling channel - (a) Intense 400 MeV H{sup -} beam, (b) Handle hydrogen (flammable) gas, (c) 5 Tesla SC solenoid magnet, (d) He cryogenic/recycling system; (2) Pillbox cavity has been refurbished to search better RF material - Beryllium button test will be happened soon; (3) E x B effect has been tested in a box cavity - Under study (result seems not to be desirable); (4) 201 MHz RF cavity with SRF cavity treatment has been tested at low magnetic field - (a) Observed some B field effect on maximum field gradient and (b) Further study is needed (large bore SC magnet will be delivered end of 2011); and (5) HPRF cavity beam test has started - (a) No RF breakdown observed and (b) Design a new HPRF cavity to investigate more plasma loading effect.

  5. Electrodeless lighting RF power source development. Final report

    SciTech Connect

    1996-08-30

    An efficient, solid state RF power source has been developed on this NICE project for exciting low power electrodeless lamp bulbs. This project takes full advantage of concurrent advances in electrodeless lamp technology. Electrodeless lamp lighting systems utilizing the sulfur based bulb type developed by Fusion Lighting, Inc., is an emerging technology which is based on generating light in a confined plasma created and sustained by RF excitation. The bulb for such a lamp is filled with a particular element and inert gas at low pressure when cold. RF power from the RF source creates a plasma within the bulb which reaches temperatures approaching those of high pressure discharge lamp plasmas. At these temperatures the plasma radiates substantial visible light with a spectrum similar to sunlight.

  6. Plasma core reactor simulations using RF uranium seeded argon discharges

    NASA Technical Reports Server (NTRS)

    Roman, W. C.

    1975-01-01

    An experimental investigation was conducted using the United Technologies Research Center (UTRC) 80 kW and 1.2 MW RF induction heater systems to aid in developing the technology necessary for designing a self-critical fissioning uranium plasma core reactor (PCR). A nonfissioning, steady-state RF-heated argon plasma seeded with pure uranium hexafluoride (UF6) was used. An overall objective was to achieve maximum confinement of uranium vapor within the plasma while simultaneously minimizing the uranium compound wall deposition. Exploratory tests were conducted using the 80 kW RF induction heater with the test chamber at approximately atmospheric pressure and discharge power levels on the order of 10 kW. Four different test chamber flow configurations were tested to permit selection of the configuration offering the best confinement characteristics for subsequent tests at higher pressure and power in the 1.2 MW RF induction heater facility.

  7. SU-E-J-71: Feasibility Study On MRI-Based BANG3 Gel Dosimetry Using Dual-Source Parallel RF Transmission System

    SciTech Connect

    Kim, S; Lee, J; Lee, D; Lee, S; Choe, B; Baek, H

    2014-06-01

    Purpose: In this work, we present the feasibility of use of the parallel RF transmission with multiple RF source (MultiTransmit) imaging in MRI-based polymer gel dosimetry. Methods: The commercially available BANG3 gel was used for gel dosimetry. Spin-spin relaxation rate R2 was used to quantify the absorbed dose. The image quality (signal-to-noise ratio, SNR; image uniformity) and B1 field inhomogeneity between conventional single-source and MultiTransmit MR imaging were compared. Finally, the estimated R2 uncertainty σ(R2) and dosimetric performance (i.e., dose resolution) between conventional single-source and MultiTransmit MR imaging were compared. Results: Image quality and B1 field homogeneity within each calibration vial and large phantom was statistically better in MultiTransmit imaging than in conventional single-source RF transmission imaging (P < 0.005 for all calibration vials). In particular, σ(R2) (defined as the standard uncertainty of R2) was lower on the MultiTransmit images than on the conventional single-source images. Furthermore, the MultiTransmit measurement gives a lower than that obtained using the conventional single-source method. Conclusion: The improved image quality and B1 homogeneity resulted in reduced dose uncertainty (i.e., σ(R2) and dose resolution) in MRI-based polymer gel dosimetry, suggesting that MultiTransmit MR imaging has potential benefits for use in clinical 3D gel dosimetry without the need for the complicated B1 field correction method.

  8. Ag on Si(111) from basic science to application

    SciTech Connect

    Belianinov, Aleksey

    2012-01-01

    In our work we revisit Ag and Au adsorbates on Si(111)-7x7, as well as experiment with a ternary system of Pentacene, Ag and Si(111). Of particular interest to us is the Si(111)-(√3x√3)R30°}–Ag (Ag-Si-√3 hereafter). In this thesis I systematically explore effects of Ag deposition on the Ag-Si-√3 at different temperatures, film thicknesses and deposition fluxes. The generated insight of the Ag system on the Si(111) is then applied to generate novel methods of nanostructuring and nanowire growth. I then extend our expertise to the Au system on the Ag-Si(111) to gain insight into Au-Si eutectic silicide formation. Finally we explore behavior and growth modes of an organic molecule on the Ag-Si interface.

  9. A compact spin-exchange optical pumping system for 3He polarization based on a solenoid coil, a VBG laser diode, and a cosine theta RF coil

    NASA Astrophysics Data System (ADS)

    Lee, Sungman; Kim, Jongyul; Moon, Myung Kook; Lee, Kye Hong; Lee, Seung Wook; Ino, Takashi; Skoy, Vadim R.; Lee, Manwoo; Kim, Guinyun

    2013-02-01

    For use as a neutron spin polarizer or analyzer in the neutron beam lines of the HANARO (High-flux Advanced Neutron Application ReactOr) nuclear research reactor, a 3He polarizer was designed based on both a compact solenoid coil and a VBG (volume Bragg grating) diode laser with a narrow spectral linewidth of 25 GHz. The nuclear magnetic resonance (NMR) signal was measured and analyzed using both a built-in cosine radio-frequency (RF) coil and a pick-up coil. Using a neutron transmission measurement, we estimated the polarization ratio of the 3He cell as 18% for an optical pumping time of 8 hours.

  10. THE AGS-BASED SUPER NEUTRINO BEAM FACILITY CONCEPTUAL DESIGN REPORT

    SciTech Connect

    WENG,W.T.; DIWAN,M.; RAPARIA,D.

    2004-10-08

    be upgraded to 0.2 s to reach the required repetition rate of 2.5 Hz. The required upgrade of the AGS power supply, the rf system, and other rate dependent accelerator issues is discussed. The design of the target/horn configuration is shown. The material selected for the proton target is a Carbon-Carbon composite. It is a 3-dimensional woven material that exhibits extremely low thermal expansion for temperatures up to 1000 C; for higher temperatures it responds like graphite. This property is important for greatly reducing the thermo-elastic stresses induced by the beam, thereby extending the life of the target. The target consists of a 80 cm long cylindrical rod of 12 mm diameter. The target intercepts a 2 mm rms proton beam of 10{sup 14} protons/pulse. The total energy deposited as heat in the target is 7.3 kJ with peak temperature rise of about 280 C. Heat will be removed from the target through forced convection of helium gas across its outside surface. The extracted proton beam uses an existing beamline at the AGS, but is then directed to a target station atop a constructed earthen hill. The target is followed by a downward slopping pion decay channel. This vertical arrangement keeps the target and decay pipe well above the water table in this area. The 11.3 degrees slope aims the neutrino beam at a water Cerenkov neutrino detector to be located in the Homestake mine at Lead, South Dakota. A 3-dimensional view of the beam transport line, target station, and decay tunnel is provided.

  11. RF sensor solutions for small lightweight unmanned aerial vehicles

    NASA Astrophysics Data System (ADS)

    Innocenti, Roberto

    2005-05-01

    A need exists for greater situational awareness at the lower echelons of the Army. Radar Frequency (RF) sensors on small, lightweight Unmanned Aerial Vehicles (UAV) could provide lower echelon commanders with all-weather reconnaissance, early warning, and target acquisition; however, the designs of these RF sensors are limited by the projected size and weight restrictions on the payload for a class II UAV. Consequently, these designs may favor combining simple RF sensor hardware with digital-signal processing (DSP) solutions over more sophisticated radar hardware. In this paper, we show the potential of simple, low cost RF sensors with hemispherical antenna coverage to overcome these limitations. The proposed RF sensor system used DSP and pre-defined UAV flight pattern to detect and track moving targets from range and Doppler information. Our objective is to conceive and model a suite of software options that, by combining UAV flight patterns and processing algorithms, will be able to detect and track moving targets. In order to accomplish this, we are building a simulation that uses sensor models, target models, and battlefield dynamics to predict the targeting capabilities of the RF sensor system. We will use this simulation (1) to determine the tradeoffs between sensor complexity (and cost) and the military significance of the information gathered, and (2) to describe sensor error budgets for endgame lethality models

  12. ILC @ SLAC R&D Program for a Polarized RF Gun

    SciTech Connect

    Clendenin, J.E.; Brachman, A.; Dowell, D.H.; Garwin, E.L.; Ioakemidi, K.; Kirby, R.E.; Maruyama, T.; Miller, R.A.; Prescott, C.Y.; Wang, J.W.; Lewellen, J.W.; Prepost, R.; /Wisconsin U., Madison

    2006-01-25

    Photocathode rf guns produce high-energy low-emittance electron beams. DC guns utilizing GaAs photocathodes have proven successful for generating polarized electron beams for accelerators, but they require rf bunching systems that significantly increase the transverse emittance of the beam. With higher extraction field and beam energy, rf guns can support higher current densities at the cathode. The source laser system can then be used to generate the high peak current, relatively low duty-factor micropulses required by the ILC without the need for post-extraction rf bunching. The net result is that the injection system for a polarized rf gun can be identical to that for an unpolarized rf gun. However, there is some uncertainty as to the survivability of an activated GaAs cathode in the environment of an operating rf gun. Consequently, before attempting to design a polarized rf gun for the ILC, SLAC plans to develop an rf test gun to demonstrate the rf operating conditions suitable for an activated GaAs cathode.

  13. RF measurements of a traveling-wave muffin-tin accelerating structure at 90 GHz

    SciTech Connect

    Chou, P.J.; Bowden, G.B.; Copeland, M.R.; Menegat, A.; Pritzkau, D.P.; Siemann, R.H.; Henke, H.

    1997-05-01

    A measuring system at the table-top scale was developed for RF measurements of a muffin-tin accelerating structure operating at 32 times the SLAC frequency (2.856 GHz). Both perturbation and non-perturbation methods are employed to characterize the RF properties of a muffin-tin structure. Conventional bead pull measurements are extended to millimeter wavelengths. Design of the measuring system and preliminary results of RF measurements are presented.

  14. Charge Accumulation Effects on Breakdown Condition of Capacitive Discharges in DC-biased RF Field

    NASA Astrophysics Data System (ADS)

    Shoji, M.; Sato, M.

    1998-10-01

    Breakdown characteristics of capacitively coupled argon dc-biased rf (13.56 MHz) discharges are measured using an insulated electrode (IE) system made from glass-covered aluminum disk plates. In the IE system under the influence of a dc-biased rf field, charged particles generated in the discharge space will accumulate at the glass surface without leakage, which may weaken the dc electric field strength. After the dc-biased rf voltage is applied, a time lag Tl until breakdown is observed and the rf breakdown voltage V_rf is considerably lowered. For example, V_rf decreases by more than 10 % at Tl = 1000 sec. The values of V_rf which cause breakdown within Tl = 20 sec. in the IE system are compared with those for the bare metal electrode (BME) system for which no charge accumulation takes place. At low dc biases, they are almost the same for both systems. As the dc bias is increased, V_rf of the BME system becomes much smaller than that of the IE system. The decrease in V_rf can be explained by the occurring of secondary electron emission from the metal surface.

  15. Physical modeling of RF source generation based on electro-optic modulation and laser injection locking

    NASA Astrophysics Data System (ADS)

    Shi, Shouyuan; Schneider, Garrett; Prather, Dennis W.

    2014-03-01

    In this paper we present a frequency domain method to model the physical behavior of widely tunable (1-100GHz) and spectrally pure (1Hz linewidth) RF source, generated by down-mixing of two coherent DFB lasers with a desired RF frequency offset. Rate equations that govern master and injection locking laser behavior are used, and linearization process is followed to derive phase and intensity noise responses by carefully examining the components in the system. Various noise sources are incorporated into the model to explore their significance to final system performance. The phase noise, and RF linewidth are simulated to evaluate the system performance of the generated RF sources.

  16. Inductively coupled wireless RF coil arrays.

    PubMed

    Bulumulla, S B; Fiveland, E; Park, K J; Foo, T K; Hardy, C J

    2015-04-01

    As the number of coils increases in multi-channel MRI receiver-coil arrays, RF cables and connectors become increasingly bulky and heavy, degrading patient comfort and slowing workflow. Inductive coupling of signals provides an attractive "wireless" approach, with the potential to reduce coil weight and cost while simplifying patient setup. In this work, multi-channel inductively coupled anterior arrays were developed and characterized for 1.5T imaging. These comprised MR receiver coils inductively (or "wirelessly") linked to secondary or "sniffer" coils whose outputs were transmitted via preamps to the MR system cabinet. The induced currents in the imaging coils were blocked by passive diode circuits during RF transmit. The imaging arrays were totally passive, obviating the need to deliver power to the coils, and providing lightweight, untethered signal reception with easily positioned coils. Single-shot fast spin echo images were acquired from 5 volunteers using a 7-element inductively coupled coil array and a conventionally cabled 7-element coil array of identical geometry, with the inductively-coupled array showing a relative signal-to-noise ratio of 0.86 +/- 0.07. The concept was extended to a larger 9-element coil array to demonstrate the effect of coil element size on signal transfer and RF-transmit blocking. PMID:25523607

  17. Silicon Micromachining in RF and Photonic Applications

    NASA Technical Reports Server (NTRS)

    Lin, Tsen-Hwang; Congdon, Phil; Magel, Gregory; Pang, Lily; Goldsmith, Chuck; Randall, John; Ho, Nguyen

    1995-01-01

    Texas Instruments (TI) has developed membrane and micromirror devices since the late 1970s. An eggcrate space membrane was used as the spatial light modulator in the early years. Discrete micromirrors supported by cantilever beams created a new era for micromirror devices. Torsional micromirror and flexure-beam micromirror devices were promising for mass production because of their stable supports. TI's digital torsional micromirror device is an amplitude modulator (known as the digital micromirror device (DMD) and is in production development, discussed elsewhere. We also use a torsional device for a 4 x 4 fiber-optic crossbar switch in a 2 cm x 2 cm package. The flexure-beam micromirror device is an analog phase modulator and is considered more efficient than amplitude modulators for use in optical processing systems. TI also developed millimeter-sized membranes for integrated optical switches for telecommunication and network applications. Using a member in radio frequency (RF) switch applications is a rapidly growing area because of the micromechanical device performance in microsecond-switching characteristics. Our preliminary membrane RF switch test structure results indicate promising speed and RF switching performance. TI collaborated with MIT for modeling of metal-based micromachining.

  18. RF Gun Photocathode Research at SLAC

    SciTech Connect

    Jongewaard, E.; Akre, R.; Brachmann, A.; Corbett, J.; Gilevich, S.; Grouev, K.; Hering, P.; P.Krejcik,; Lewandowski, J.; Loos, H.; Montagne, T.; Sheppard, J.C.; Stefan, P.; Vlieks, A.; Weathersby, S.; Zhou, F.; /SLAC

    2012-05-16

    LCLS is presently operating with a third copper photocathode in the original rf gun, with a quantum efficiency (QE) of {approx}1 x 10{sup -4} and projected emittance {gamma}{var_epsilon}{sub x,y} = 0.45 {micro}m at 250 pC bunch charge. The spare LCLS gun is installed in the SLAC Accelerator Structure Test Area (ASTA), fully processed to high rf power. As part of a wider photocathode R and D program, a UV laser system and additional gun diagnostics are being installed at ASTA to measure QE, QE lifetime, and electron beam emittance under a variety of operating conditions. The near-term goals are to test and verify the spare photocathode production/installation sequence, including transfer from the final holding chamber to the rf gun. Mid- and longer-term goals include development of a rigorous understanding of plasma and laser-assisted surface conditioning and investigation of new, high-QE photocathode materials. In parallel, an x-ray photoemission spectroscopy station is nearing completion, to analyze Cu photocathode surface chemistry. In this paper we review the status and anticipated operating parameters of ASTA and the spectroscopy test chamber.

  19. RF Photonic Technology in Optical Fiber Links

    NASA Astrophysics Data System (ADS)

    Chang, William S. C.

    2007-06-01

    List of contributors; Introduction and preface; 1. Figures of merit and performance analysis of photonic microwave links Charles Cox and William S. C. Chang; 2. RF subcarrier links in local access networks Xiaolin Lu; 3. Analog modulation of semiconductor lasers Joachim Piprek and John E. Bowers; 4. LiNbO3 external modulators and their use in high performance analog links Gary E. Betts; 5. Broadband traveling wave modulators in LiNbO3 Marta M. Howerton and William K. Burns; 6. Multiple quantum well electroabsorption modulators for RF photonic links William S. C. Chang; 7. Polymer modulators for RF photonics Timothy Van Eck; 8. Photodiodes for high performance analog links P. K. L. Yu and Ming C. Wu; 9. Opto-electronic oscillators X. Steve Yao; 10. Photonic link techniques for microwave frequency conversion Stephen A. Pappert, Roger Helkey and Ronald T. Logan Jr; 11. Antenna-coupled millimeter-wave electro-optical modulators William B. Bridges; 12. System design and performance of wideband photonic phased array antennas Greg L. Tangonan, Willie Ng, Daniel Yap and Ron Stephens; Acknowledgements; References; Index.

  20. Studies on characterizing the transmission of RF signals over a turbulent FSO link.

    PubMed

    Dat, Pham Tien; Bekkali, Abdemoula; Kazaura, Kamugisha; Wakamori, Kazuhiko; Suzuki, Toshiji; Matsumoto, Mitsuji; Higashino, Takeshi; Tsukamoto, Katsutoshi; Komaki, Shozo

    2009-05-11

    In this paper, we present an experimental study on transmission of RF signals over turbulent free-space optics (FSO) channel by using off-the-shelf Radio Frequency - FSO (RF-FSO) antennas. The results demonstrate potential of utilizing FSO links for transmission of RF signals and are used as a guideline in the design, prediction and evaluation of an advanced Dense Wavelength Division Multiplexing (DWDM) RoFSO system we are developing capable of transmitting multiple RF signals. An analytical modeling of the system is also conducted to identify key parameters in evaluating the performance of RF signal transmission using FSO links. The results confirm that the effect of scintillation on RF-FSO system performance can be estimated by using a simple estimation equation and satisfactory result are obtained from comparing the experimental and theoretical derived data under weak to strong turbulence condition.

  1. Preparation, characterization, and photocatalytic activity of porous AgBr@Ag and AgBrI@Ag plasmonic photocatalysts

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Tian, Baozhu; Zhang, Jinlong; Xiong, Tianqing; Wang, Tingting

    2014-02-01

    Porous AgBr@Ag and AgBrI@Ag plasmonic photocatalysts were synthesized by a multistep route, including a dealloying method to prepare porous Ag, a transformation from Ag to AgBr and AgBrI, and a photo-reduction process to form Ag nanoparticles on the surface of AgBr and AgBrI. It was found that the porous structure kept unchanged during Ag was transferred into AgBr, AgBrI, AgBr@Ag, and AgBrI@Ag. Both porous AgBr@Ag and porous AgBrI@Ag showed much higher visible-light photocatalytic activity than cubic AgBr@Ag for the degradation of methyl orange, which is because the interconnected pore channels not only provide more reactive sites but also favor the transportation of photo-generated electrons and holes. For AgBrI@Ag, AgBrI solid solution formed at the interface of AgBr and AgI, and the phase junction can effectively separate the photo-generated electrons and holes, favorable to the improvement of photocatalytic activity. The optimal I content for obtaining the highest activity is ∼10 at.%.

  2. Additive manufacturing of RF absorbers

    NASA Astrophysics Data System (ADS)

    Mills, Matthew S.

    The ability of additive manufacturing techniques to fabricate integrated electromagnetic absorbers tuned for specific radio frequency bands within structural composites allows for unique combinations of mechanical and electromagnetic properties. These composites and films can be used for RF shielding of sensitive electromagnetic components through in-plane and out-of-plane RF absorption. Structural composites are a common building block of many commercial platforms. These platforms may be placed in situations in which there is a need for embedded RF absorbing properties along with structural properties. Instead of adding radar absorbing treatments to the external surface of existing structures, which adds increased size, weight and cost; it could prove to be advantageous to integrate the microwave absorbing properties directly into the composite during the fabrication process. In this thesis, a method based on additive manufacturing techniques of composites structures with prescribed electromagnetic loss, within the frequency range 1 to 26GHz, is presented. This method utilizes screen printing and nScrypt micro dispensing to pattern a carbon based ink onto low loss substrates. The materials chosen for this study will be presented, and the fabrication technique that these materials went through to create RF absorbing structures will be described. The calibration methods used, the modeling of the RF structures, and the applications in which this technology can be utilized will also be presented.

  3. Ion bombardment in RF photoguns

    SciTech Connect

    Pozdeyev,E.; Kayran, D.; Litvinenko, V. N.

    2009-05-04

    A linac-ring eRHIC design requires a high-intensity CW source of polarized electrons. An SRF gun is viable option that can deliver the required beam. Numerical simulations presented elsewhere have shown that ion bombardment can occur in an RF gun, possibly limiting lifetime of a NEA GaAs cathode. In this paper, we analytically solve the equations of motion of ions in an RF gun using the ponderomotive potential of the Rf field. We apply the method to the BNL 1/2-cell SRF photogun and demonstrate that a significant portion of ions produced in the gun can reach the cathode if no special precautions are taken. Also, the paper discusses possible mitigation techniques that can reduce the rate of ion bombardment.

  4. Cryogenic vacuumm RF feedthrough device

    DOEpatents

    Wu, Genfa; Phillips, Harry Lawrence

    2008-12-30

    A cryogenic vacuum rf feedthrough device comprising: 1) a probe for insertion into a particle beam; 2) a coaxial cable comprising an inner conductor and an outer conductor, a dielectric/insulating layer surrounding the inner conductor, the latter being connected to the probe for the transmission of higher mode rf energy from the probe; and 3) a high thermal conductivity stub attached to the coaxial dielectric about and in thermal contact with the inner conductor which high thermal conductivity stub transmits heat generated in the vicinity of the probe efficiently and radially from the area of the probe and inner conductor all while maintaining useful rf transmission line characteristics between the inner and outer coaxial conductors.

  5. rf improvements for Spallation Neutron Source H- ion sourcea)

    NASA Astrophysics Data System (ADS)

    Kang, Y. W.; Fuja, R.; Goulding, R. H.; Hardek, T.; Lee, S.-W.; McCarthy, M. P.; Piller, M. C.; Shin, K.; Stockli, M. P.; Welton, R. F.

    2010-02-01

    The Spallation Neutron Source at Oak Ridge National Laboratory is ramping up the accelerated proton beam power to 1.4 MW and just reached 1 MW. The rf-driven multicusp ion source that originates from the Lawrence Berkeley National Laboratory has been delivering ˜38 mA H- beam in the linac at 60 Hz, 0.9 ms. To improve availability, a rf-driven external antenna multicusp ion source with a water-cooled ceramic aluminum nitride (AlN) plasma chamber is developed. Computer modeling and simulations have been made to analyze and optimize the rf performance of the new ion source. Operational statistics and test runs with up to 56 mA medium energy beam transport beam current identify the 2 MHz rf system as a limiting factor in the system availability and beam production. Plasma ignition system is under development by using a separate 13 MHz system. To improve the availability of the rf power system with easier maintenance, we tested a 70 kV isolation transformer for the 80 kW, 6% duty cycle 2 MHz amplifier to power the ion source from a grounded solid-state amplifier.

  6. RF Power Upgrade for CEBAF at Jefferson Laboratory

    SciTech Connect

    Andrew Kimber,Richard Nelson

    2011-03-01

    Jefferson Laboratory (JLab) is currently upgrading the 6GeV Continuous Electron Beam Accelerator Facility (CEBAF) to 12GeV. As part of the upgrade, RF systems will be added, bringing the total from 340 to 420. Existing RF systems can provide up to 6.5 kW of CW RF at 1497 MHZ. The 80 new systems will provide increased RF power of up to 13 kW CW each. Built around a newly designed and higher efficiency 13 kW klystron developed for JLab by L-3 Communications, each new RF chain is a completely revamped system using hardware different than our present installations. This paper will discuss the main components of the new systems including the 13 kW klystron, waveguide isolator, and HV power supply using switch-mode technology. Methodology for selection of the various components and results of initial testing will also be addressed. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

  7. Structural, Morphological and Antibacterial Investigation of Ag-Impregnated Sol-Gel-Derived 45S5 NanoBioglass Systems.

    PubMed

    Durgalakshmi, D; Balakumar, S; Raja, C Ashok; George, Rani P; Mudali, U Kamachi

    2015-06-01

    An increasing percentage of ageing population requires 30-year survivability of orthopedic devices that is not possible with the current bioinert materials, having a maximum of 15-year survivability. To satisfy this growing need, a shift is needed from replacement of tissues to regeneration of tissues. This is highly possible through the use of silica-bioactive glasses. However, a failure of implant can occur due to infections even by using such materials. Advances in using silver for antibacterial applications have been commercialized. However, higher concentrations of silver also lead to toxic effects. In this study, nanoBioglass 45S5 (NBG) and Ag-NBG were synthesized by using sol-gel method followed by solution-phase method, respectively. The bioactive crystals such as Na2Ca2Si3O9, CaCO3, and AgPO3, very much needed in the field of bone tissue engineering and in antibacterial strategies, were obtained in the NBG Matrix. The morphological investigation of NBG with 1 mM Ag+ concentrations shows the nanospikes arrangement of size 30-40 nm with spherical porous structure of size 10-20 nm, which supports the formation of collagen molecular fibrils on the surface of NBG matrices and enhances osseointegration. Both gram-positive and gram-negative strains show higher antibacterial activity for nanoBioglass with 1 mM Ag+ concentration. PMID:26369040

  8. In Situ Fabrication of 3D Ag@ZnO Nanostructures for Microfluidic Surface-Enhanced Raman Scattering Systems

    PubMed Central

    2015-01-01

    In this work, we develop an in situ method to grow highly controllable, sensitive, three-dimensional (3D) surface-enhanced Raman scattering (SERS) substrates via an optothermal effect within microfluidic devices. Implementing this approach, we fabricate SERS substrates composed of Ag@ZnO structures at prescribed locations inside microfluidic channels, sites within which current fabrication of SERS structures has been arduous. Conveniently, properties of the 3D Ag@ZnO nanostructures such as length, packing density, and coverage can also be adjusted by tuning laser irradiation parameters. After exploring the fabrication of the 3D nanostructures, we demonstrate a SERS enhancement factor of up to ∼2 × 106 and investigate the optical properties of the 3D Ag@ZnO structures through finite-difference time-domain simulations. To illustrate the potential value of our technique, low concentrations of biomolecules in the liquid state are detected. Moreover, an integrated cell-trapping function of the 3D Ag@ZnO structures records the surface chemical fingerprint of a living cell. Overall, our optothermal-effect-based fabrication technique offers an effective combination of microfluidics with SERS, resolving problems associated with the fabrication of SERS substrates in microfluidic channels. With its advantages in functionality, simplicity, and sensitivity, the microfluidic-SERS platform presented should be valuable in many biological, biochemical, and biomedical applications. PMID:25402207

  9. Measurement of diffusion coefficient using a diaphragm cell: PbBr 2AgBr system

    NASA Astrophysics Data System (ADS)

    Singh, N. B.; Glicksman, M. E.; Coriell, S. R.; Duval, W. M. B.; Santoro, G. J.; DeWitt, R.

    1996-09-01

    The diffusion coefficient of molten lead bromide-silver bromide was determined using a two chamber diaphragm cell separated by the porous membrane of a sintered glass disk. Only dilute mixtures of PbBr 2AgBr were studied. The interdiffusion coefficient was determined to be 1.71 × 10 -5cm 20/s.

  10. The integrated optic RF spectrum analyzer

    NASA Technical Reports Server (NTRS)

    Pedinoff, M. E.; Ranganath, T. R.; Joseph, T. R.; Lee, J. Y.

    1981-01-01

    The results of measurements made on a fully integrated optic RF spectrum analyzer (IOSA) are reported. The performance of the device acousto-optic bandwidth, single-tone RF resolution, two-tone RF resolution, single-tone dynamic range, two-tone dynamic range, and single-tone RF response are presented. The device parameters that control device performance are analyzed. These results demonstrate the viability of the IOSA for real time spectrum analysis of pulsed and CW RF signals. Improvements of RF bandwidth resolution can be obtained by the use of larger collimated optical beams which requires larger optical lens elements, and hence, larger crystals.

  11. AgPO2F2 and Ag9(PO2F2)14: the first Ag(i) and Ag(i)/Ag(ii) difluorophosphates with complex crystal structures.

    PubMed

    Malinowski, Przemysław J; Kurzydłowski, Dominik; Grochala, Wojciech

    2015-12-01

    The reaction of AgF2 with P2O3F4 yields a mixed valence Ag(I)/Ag(II) difluorophosphate salt with AgAg(PO2F2)14 stoichiometry - the first Ag(ii)-PO2F2 system known. This highly moisture sensitive brown solid is thermally stable up to 120 °C, which points at further feasible extension of the chemistry of Ag(ii)-PO2F2 systems. The crystal structure shows a very complex bonding pattern, comprising of polymeric Ag(PO2F2)14(4-) anions and two types of Ag(I) cations. One particular Ag(II) site present in the crystal structure of Ag9(PO2F2)14 is the first known example of square pyramidal penta-coordinated Ag(ii) in an oxo-ligand environment. Ag(i)PO2F2 - the product of the thermal decomposition of Ag9(PO2F2)14 - has also been characterized by thermal analysis, IR spectroscopy and X-ray powder diffraction. It has a complicated crystal structure as well, which consists of infinite 1D [Ag(I)O4/2] chains which are linked to more complex 3D structures via OPO bridges. The PO2F2(-) anions bind to cations in both compounds as bidentate oxo-ligands. The terminal F atoms tend to point inside the van der Waals cavities in the crystal structure of both compounds. All important structural details of both title compounds were corroborated by DFT calculations. PMID:26200921

  12. Plasma rotation induced by RF

    SciTech Connect

    Chan, V. S.; Chiu, S. C.; Lin-Liu, Y. R. [General Atomics, P.O. Box 85608, San Diego, California 92186-5698; Omelchenko, Y. A. [General Atomics, P.O. Box 85608, San Diego, California 92186-5698

    1999-09-20

    Plasma rotation has many beneficial effects on tokamak operation including stabilization of MHD and microturbulence to improve the beta limit and confinement. Contrary to present-day tokamaks, neutral beams may not be effective in driving rotation in fusion reactors; hence the investigation of radiofrequency (RF) induced plasma rotation is of great interest and potential importance. This paper reviews the experimental results of RF induced rotation and possible physical mechanisms, suggested by theories, to explain the observations. This subject is only in the infancy of its research and many challenging issues remained to be understood and resolved. (c) 1999 American Institute of Physics.

  13. RF-source resistance meters

    NASA Technical Reports Server (NTRS)

    Oakley, E. C. (Inventor)

    1973-01-01

    Several embodiments of RF source resistance measuring devices are disclosed. Common to all embodiments in the feature of the inclusion of at least one variable resistor, and a peak readout meter. In one embodiment, two ganged unloaded potentiometers are employed while another embodiment comprises an automaticnulling RF power bridge circuit with a variable rather than a fixed bridge reference resistance. A third embodiment comprises a calorimeter with a varible rather than a fixed resistor, while in another embodiment attenuator pads with variable resistors are employed.

  14. Compact superconducting rf-dipole cavity designs for deflecting and crabbing applications

    SciTech Connect

    De Silva, Subashini; Delayen, Jean R.; Castilla, Alejandro

    2013-06-01

    Over the years the superconducting parallel-bar design has evolved into an rf-dipole cavity with improved properties. The new rf-dipole design is considered for a number of deflecting and crabbing applications. Some of those applications are the 499 MHz rf separator system for the Jefferson Lab 12 GeV upgrade, the 400 MHz crabbing cavity system for the proposed LHC high luminosity upgrade, and the 750 MHz crabbing cavity for the medium energy electron-ion collider in Jefferson Lab. In this paper we present the optimized rf design in terms of rf performance including rf properties, higher order modes (HOM) properties, multipacting and multipole expansion for the above mentioned applications.

  15. RF Processing the NLCTA Injector Using Real Time Graphical Vacuum Displays

    NASA Astrophysics Data System (ADS)

    Gold, Saul L.

    1997-05-01

    One of the objectives of the NLCTA is to demonstrate the reliable operation of high peak power X-band RF transmission and acceleration systems. RF processing is an important function in this endeavor. The first klystron, pulse compression (SLEDII) and injector accelerator sections were processed to 50 MW SLED input power with a power multiplication at the output of SLEDII of almost 4. The paper describes RF processing by the use of real time graphical instrumentation that allows the viewing and recording of system vacuum levels and RF breakdown.

  16. Negative ion source with external RF antenna

    DOEpatents

    Leung, Ka-Ngo; Hahto, Sami K.; Hahto, Sari T.

    2007-02-13

    A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source. A converter can be included in the ion source to produce negative ions.

  17. Design and optimization for variable rate selective excitation using an analytic RF scaling function.

    PubMed

    Gai, Neville D; Zur, Yuval

    2007-11-01

    At higher B(0) fields, specific absorption rate (SAR) deposition increases. Due to maximum SAR limitation, slice coverage decreases and/or scan time increases. Conventional selective RF pulses are played out in conjunction with a time independent field gradient. Variable rate selective excitation (VERSE) is a technique that modifies the original RF and gradient waveforms such that slice profile is unchanged. The drawback is that the slice profile for off-resonance spins is distorted. A new VERSE algorithm based on modeling the scaled waveforms as a Fermi function is introduced. It ensures that system related constraints of maximum gradient amplitude and slew rate are not exceeded. The algorithm can be used to preserve the original RF pulse duration while minimizing SAR and peak b1 or to minimize the RF pulse duration. The design is general and can be applied to any symmetrical or asymmetrical RF waveform. The algorithm is demonstrated by using it to (a) minimize the SAR of a linear phase RF pulse, (b) minimize SAR of a hyperbolic secant RF pulse, and (c) minimize the duration of a linear phase RF pulse. Images with a T1-FLAIR (T1 FLuid Attenuated Inversion Recovery) sequence using a conventional and VERSE adiabatic inversion RF pulse are presented. Comparison of images and scan parameters for different anatomies and coils shows increased scan coverage and decreased SAR with the VERSE inversion RF pulse, while image quality is preserved.

  18. Workgroup Report: Base Stations and Wireless Networks—Radiofrequency (RF) Exposures and Health Consequences

    PubMed Central

    Valberg, Peter A.; van Deventer, T. Emilie; Repacholi, Michael H.

    2007-01-01

    Radiofrequency (RF) waves have long been used for different types of information exchange via the airwaves—wireless Morse code, radio, television, and wireless telephony (i.e., construction and operation of telephones or telephonic systems). Increasingly larger numbers of people rely on mobile telephone technology, and health concerns about the associated RF exposure have been raised, particularly because the mobile phone handset operates in close proximity to the human body, and also because large numbers of base station antennas are required to provide widespread availability of service to large populations. The World Health Organization convened an expert workshop to discuss the current state of cellular-telephone health issues, and this article brings together several of the key points that were addressed. The possibility of RF health effects has been investigated in epidemiology studies of cellular telephone users and workers in RF occupations, in experiments with animals exposed to cell-phone RF, and via biophysical consideration of cell-phone RF electric-field intensity and the effect of RF modulation schemes. As summarized here, these separate avenues of scientific investigation provide little support for adverse health effects arising from RF exposure at levels below current international standards. Moreover, radio and television broadcast waves have exposed populations to RF for > 50 years with little evidence of deleterious health consequences. Despite unavoidable uncertainty, current scientific data are consistent with the conclusion that public exposures to permissible RF levels from mobile telephony and base stations are not likely to adversely affect human health. PMID:17431492

  19. MEQALAC rf accelerating structure

    SciTech Connect

    Keane, J.; Brodowski, J.

    1981-01-01

    A prototype MEQALAC capable of replacing the Cockcroft Walton pre-injector at BNL is being fabricated. Ten milliamperes of H/sup -/ beam supplied from a source sitting at a potential of -40 kilovolt is to be accelerated to 750 keV. This energy gain is provided by a 200 Megahertz accelerating system rather than the normal dc acceleration. Substantial size and cost reduction would be realized by such a system over conventional pre-accelerator systems.

  20. Ultrananocrystalline diamond films with optimized dielectric properties for advanced RF MEMS capacitive switches

    DOEpatents

    Sumant, Anirudha V.; Auciello, Orlando H.; Mancini, Derrick C.

    2013-01-15

    An efficient deposition process is provided for fabricating reliable RF MEMS capacitive switches with multilayer ultrananocrystalline (UNCD) films for more rapid recovery, charging and discharging that is effective for more than a billion cycles of operation. Significantly, the deposition process is compatible for integration with CMOS electronics and thereby can provide monolithically integrated RF MEMS capacitive switches for use with CMOS electronic devices, such as for insertion into phase array antennas for radars and other RF communication systems.