WorldWideScience

Sample records for hom coupler design

  1. HOM/LOM Coupler Study for the ILC Crab Cavity

    International Nuclear Information System (INIS)

    Xiao, L.; Li, Z.; Ko, K.

    2007-01-01

    The FNAL 9-cell 3.9GHz deflecting mode cavity designed for the CKM experiment was chosen as the baseline design for the ILC BDS crab cavity. The full 9-cell CKM cavity including the coupler end-groups was simulated using the parallel eigensolver Omega3P and scattering parameter solver S3P. It was found that both the notch filters for the HOM/LOM couplers are very sensitive to the notch gap, which is about 1.6MHz/micron and is more than 10 times more sensitive than the TTF cavity. It was also found in the simulation that the unwanted vertical π-mode (SOM) is strongly coupled to the horizontal 7π/9 mode which causes x-y coupling and reduces the effectiveness of the SOM damping. To meet the ILC requirements, the HOM/LOM couplers are redesigned to address these issues. With the new designs, the damping of the HOM/LOM modes is improved. The sensitivity of the notch filter for the HOM coupler is reduced by one order of magnitude. The notch filter for the LOM coupler is eliminated in the new design which significantly simplifies the geometry. In this paper, we will present the simulation results of the original CKM cavity and the progresses on the HOM/LOM coupler re-design and optimization

  2. HOM Coupler Optimisation for the Superconducting RF Cavities in ESS

    CERN Document Server

    Ainsworth, R; Calaga, R

    2012-01-01

    The European Spallation Source (ESS) will be the world’s most powerful next generation neutron source. It consists of a linear accelerator, target, and instruments for neutron experiments. The linac is designed to accelerate protons to a final energy of 2.5 GeV, with an average design beam power of 5 MW, for collision with a target used to produce a high neutron flux. A section of the linac will contain Superconducting RF (SCRF) cavities designed at 704 MHz. Beam induced HOMs in these cavities may drive the beam unstable and increase the cryogenic load, therefore HOM couplers are installed to provide sufficient damping. Previous studies have shown that these couplers are susceptible to multipacting, a resonant process which can absorb RF power and lead to heating effects. This paper will show how a coupler suffering from multipacting has been redesigned to limit this effect. Optimisation of the RF damping is also discussed.

  3. Thermal behaviour analysis of SRF cavities and superconducting HOM couplers

    International Nuclear Information System (INIS)

    Fouaidy, M.; Junquera, T.

    1993-01-01

    Two individual papers appear in this report, titled Thermal model calculations in superconducting RF cavities, and Thermal study of HOM couplers for superconducting RF cavities. Both were indexed separately for the INIS database. (R.P.)

  4. Measuring the performance of the coaxial HOM coupler on a 2-cell TESLA-shape copper cavity

    International Nuclear Information System (INIS)

    Wang Fang; Wang Erdong; Zhang Baocheng; Zhao Kui

    2009-01-01

    Coaxial High Order Mode (HOM) couplers have been fabricated at Peking University and their RF performance has been measured on a test device consisting of a coaxial transmission line and a 2-cell TESLA-shape copper cavity. The test results on the 2-cell TESLA-shape copper cavity with HOM couplers indicate that the coupler can cut off the fundamental mode TM 010 and absorb HOMs effectively after a careful adjustment. The optimal angle of the HOM coupler with the beam tube is found. The initial test results of HOM couplers are presented in this paper. (authors)

  5. ANSYS modeling of thermal contraction of SPL HOM couplers during cool-down

    CERN Document Server

    Papke, K

    2016-01-01

    During the cool-down the HOM coupler as well as the cavity inside the cryo module experience a thermal contraction. For most materials between room temperature and liquid helium temperatures, the changes in dimension are in the order of a few tenths of a percent change in volume. This paper presents the effect of thermal contraction on the RF transmission behavior of HOM couplers, and in particular the influence on its notch filter. Furthermore the simulation process with APDL is explained in detail. Conclusions about the necessary tuning range of the notch filter are made which is especially a concern for couplers with only notch filter.

  6. Coupler developments at CERN

    International Nuclear Information System (INIS)

    Cavallari, G.; Chiaveri, E.; Haebel, E.; Legendre, P.; Weingarten, W.

    1988-01-01

    This paper discusses the coupler developments that have taken place at CERN since the last RF superconductivity workshop. At that time beam tube coupling was just starting to be examined. It was found that in restricting the number of cells to four with the correct amount of intercell coupling, and endcells compensated simultaneously for several modes, trapped modes can be avoided at least up to three and a half times the fundamental mode frequency. This result is regarded as a sufficiently safe basis to switch over to beam tube coupling with two higher order mode (hom) couplers, one on each side and with 65 degrees in between them, and in addition one beam tube power coupler. The characteristics of the cavity and the machine determine the basic coupler specifications. Four designs are discussed for hom couplers. 22 reference, 15 figures, 2 tables

  7. The Design of a Five-Cell Superconducting RF Module with a PBG Coupler Cell

    International Nuclear Information System (INIS)

    Arsenyev, Sergey A.; Simakov, Evgenya I.

    2012-01-01

    We discuss the problem of incorporating a Photonic Band Gap (PBG) cell into a superconducting accelerating module of 5 cells designed for the operational frequency of 2.1 GHz. The reason for using a PBG cell is to provide a good accelerating mode confinement and good Higher Order Mode (HOM) suppression. PBG cell can potentially be used for placing HOM and fundamental mode couplers. However, because of the naturally higher ratio of the peak magnetic field to the accelerating field in the PBG cell, it should be designed to operate at a lower accelerating gradient than the other cells of the module. This ensures that the probability of quench in the PBG cell would be no higher than in other elliptical cells of the structure.

  8. Development of higher order mode couplers at Cornell

    International Nuclear Information System (INIS)

    Amato, J.C.

    1988-01-01

    Higher order mode (HOM) couplers are integral parts of a superconducting accelerator cavity. The damping which the couplers must provide is dictated by the frequency and shunt impedance of the cavity modes as well as by the stability requirements of the accelerator incorporating the cavities. Cornell's 5-cell 1500 MHz elliptical cavity was designed for use in a 50 x 50 GeV electron-positron storage ring with a total beam current of 3.5 mA (CESR-II). HOM couplers for the Cornell cavity were designed and evaluated with this machine in mind. The development of these couplers is described in this paper. 8 references, 8 figures

  9. Five-cell superconducting RF module with a PBG coupler cell: design and cold testing of the copper prototype

    Energy Technology Data Exchange (ETDEWEB)

    Arsenyev, Sergey Andreyevich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Simakov, Evgenya Ivanovna [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Shchegolkov, Dmitry [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Boulware, Chase [Niowave, Lansing, MI (United States); Grimm, Terry [Niowave, Lansing, MI (United States); Rogacki, Adam [Niowave, Lansing, MI (United States)

    2015-04-29

    We report the design and experimental data for a copper prototype of a superconducting radio-frequency (SRF) accelerator module. The five-cell module has an incorporated photonic band gap (PBG) cell with couplers. The purpose of the PBG cell is to achieve better higher order mode (HOM) damping, which is vital for preserving the quality of high-current electron beams. Better HOM damping raises the current threshold for beam instabilities in novel SRF accelerators. The PBG design also increases the real-estate gradient of the linac because both HOM damping and the fundamental power coupling can be done through the PBG cell instead of on the beam pipe via complicated end assemblies. First, we will discuss the design and accelerating properties of the structure. The five-cell module was optimized to provide good HOM damping while maintaining the same accelerating properties as conventional elliptical-cell modules. We will then discuss the process of tuning the structure to obtain the desired accelerating gradient profile. Finally, we will list measured quality factors for the accelerating mode and the most dangerous HOMs.

  10. HOM power in FCC-ee cavities

    CERN Document Server

    Karpov, Ivan; Chapochnikova, Elena

    2018-01-01

    This Note summarizes the results of the power loss calculations for FCC-ee machines with 400.79 MHz cavity options. The requirements for the single-cell cavity design and for the operation with beam are obtained from the results for the high-current FCC-ee machine (Z). For other machines the power loss is sufficiently low and can be absorbed and extracted by foreseen HOM couplers.

  11. Tolerance study for the components of the probe-type and hook-type Higher Order Mode couplers for the HL-LHC 800 MHz harmonic system

    CERN Document Server

    Blanco, Esteban

    2016-01-01

    A superconducting 800 MHz second harmonic RF system is one of the considered options as a Landau damping mechanism for HiLumi LHC. The Higher Order Mode (HOM) coupler designs require tight manufacturing tolerances in order to operate at the design specifications. The project consists of defining the mechanical tolerances for the different components of both the probe-type and hook-type HOM coupler. With the use of electromagnetic field simulation software it is possible to identify the critical components of the HOM coupler and to quantify their respective tolerances. The obtained results are discussed in this paper.

  12. Design of the new couplers for C-ADS RFQ

    Science.gov (United States)

    Shi, Ai-Min; Sun, Lie-Peng; Zhang, Zhou-Li; Xu, Xian-Bo; Shi, Long-Bo; Li, Chen-Xing; Wang, Wen-Bin

    2015-04-01

    A new special coupler with a kind of bowl-shaped ceramic window for a proton linear accelerator named the Chinese Accelerator Driven System (C-ADS) at the Institute of Modern Physics (IMP) has been simulated and constructed and a continuous wave (CW) beam commissioning through a four-meter long radio frequency quadruple (RFQ) was completed by the end of July 2014. In the experiments of conditioning and beam, some problems were promoted gradually such as sparking and thermal issues. Finally, two new couplers were passed with almost 110 kW CW power and 120 kW pulsed mode, respectively. The 10 mA intensity beam experiments have now been completed, and the couplers during the operation had no thermal or electro-magnetic problems. The detailed design and results are presented in the paper. Supported by Strategic Priority Research Program of Chinese Academy of Sciences (XDA03020500)

  13. Analysis and design of arrayed waveguide gratings with MMI couplers.

    Science.gov (United States)

    Munoz, P; Pastor, D; Capmany, J

    2001-09-24

    We present an extension of the AWG model and design procedure described in [1] to incorporate multimode interference, MMI, couplers. For the first time to our knowledge, a closed formula for the passing bands bandwidth and crosstalk estimation plots are derived.

  14. Low-crosstalk orbital angular momentum fiber coupler design.

    Science.gov (United States)

    Zhang, Zhishen; Gan, Jiulin; Heng, Xiaobo; Li, Muqiao; Li, Jiong; Xu, Shanhui; Yang, Zhongmin

    2017-05-15

    A fiber coupler for low-crosstalk orbital angular momentum mode beam splitter is proposed with the structure of two separate and parallel microfibers. By properly setting the center-to-center distance between microfibers, the crosstalk is less than -20 dB, which means that the purity of the needed OAM mode in output port is higher than 99%. For a fixed overlapping length, high coupling efficiency (>97%) is achieved in 1545-1560 nm. The operating wavelength is tuned to the whole C-band by using the thermosensitive liquid. So the designed coupler can achieve the tunable coupling ratio over the whole C-band, which is a prospective component for the further OAM fiber system.

  15. Comparison of coaxial higher order mode couplers for the CERN Superconducting Proton Linac study

    CERN Document Server

    AUTHOR|(CDS)2085329; Gerigk, Frank; Van Rienen, Ursula

    2017-01-01

    Higher order modes (HOMs) may affect beam stability and refrigeration requirements of superconducting proton linacs such as the Superconducting Proton Linac, which is studied at CERN. Under certain conditions beam-induced HOMs can accumulate sufficient energy to destabilize the beam or quench the superconducting cavities. In order to limit these effects, CERN considers the use of coaxial HOM couplers on the cutoff tubes of the 5-cell superconducting cavities. These couplers consist of resonant antennas shaped as loops or probes, which are designed to couple to potentially dangerous modes while sufficiently rejecting the fundamental mode. In this paper, the design process is presented and a comparison is made between various designs for the high-beta SPL cavities, which operate at 704.4 MHz. The rf and thermal behavior as well as mechanical aspects are discussed. In order to verify the designs, a rapid prototype for the favored coupler was fabricated and characterized on a low-power test-stand.

  16. Design and characterization of dielectric-loaded plasmonic directional couplers

    DEFF Research Database (Denmark)

    Stær, Tobias Holmgaard; Chen, Zhuo; Bozhevolnyi, Sergey

    2009-01-01

    Ultracompact directional couplers (DCs) based on dielectric-loaded surface plasmon-polariton waveguides (DLSPPWs) are analyzed using the effective index method (EIM), with the coupling, both in the parallel interaction region and in- and out-coupling regions, being taken into account. Near-field...... characterization of fabricated DCs performed with a scanning near-field optical microscope verifies the applicability of the EIM in the analysis and design of DLSPPW-based wavelength-selective DCs. The design approach applicable to a large variety of integrated optical waveguides is developed, enabling...

  17. Higher Order Mode (HOM) Impedance and Damping Study for the LHC Capture Cavity

    CERN Document Server

    Linnecar, Trevor Paul R; Tückmantel, Joachim; CERN. Geneva. SPS and LHC Division

    2001-01-01

    To investigate the higher order mode, HOM, damping in the LHC 200MHz ACN cavity when using four HOM couplers, simulations have been done by both 3-D frequency domain and time domain methods. These simulations have previously been used in other studies of HOM damped cavities and shown to be effective by comparing measurement and simulation results[1] [2]. Using these methods the impedance spectrum of the HOM modes in the cavity before and after damping has been obtained. From this, detailed information about the HOM coupler's contribution to HOM damping can be obtained. The distribution and magnitude of some potentially dangerous HOM modes in the ACN cavity have been found.

  18. Design and fabrication of multimode interference couplers based on digital micro-mirror system

    Science.gov (United States)

    Wu, Sumei; He, Xingdao; Shen, Chenbo

    2008-03-01

    Multimode interference (MMI) couplers, based on the self-imaging effect (SIE), are accepted popularly in integrated optics. According to the importance of MMI devices, in this paper, we present a novel method to design and fabricate MMI couplers. A technology of maskless lithography to make MMI couplers based on a smart digital micro-mirror device (DMD) system is proposed. A 1×4 MMI device is designed as an example, which shows the present method is efficient and cost-effective.

  19. A calculation method for RF couplers design based on numerical simulation by microwave studio

    International Nuclear Information System (INIS)

    Wang Rong; Pei Yuanji; Jin Kai

    2006-01-01

    A numerical simulation method for coupler design is proposed. It is based on the matching procedure for the 2π/3 structure given by Dr. R.L. Kyhl. Microwave Studio EigenMode Solver is used for such numerical simulation. the simulation for a coupler has been finished with this method and the simulation data are compared with experimental measurements. The results show that this numerical simulation method is feasible for coupler design. (authors)

  20. Higher order mode damping in a five-cell superconducting rf cavity with a photonic band gap coupler cell

    Science.gov (United States)

    Arsenyev, Sergey A.; Temkin, Richard J.; Shchegolkov, Dmitry Yu.; Simakov, Evgenya I.; Boulware, Chase H.; Grimm, Terry L.; Rogacki, Adam R.

    2016-08-01

    We present a study of higher order mode (HOM) damping in the first multicell superconducting radio-frequency (SRF) cavity with a photonic band gap (PBG) coupler cell. Achieving higher average beam currents is particularly desirable for future light sources and particle colliders based on SRF energy-recovery linacs (ERLs). Beam current in ERLs is limited by the beam breakup instability, caused by parasitic HOMs interacting with the beam in accelerating cavities. A PBG cell incorporated in an accelerating cavity can reduce the negative effect of HOMs by providing a frequency selective damping mechanism, thus allowing significantly higher beam currents. The five-cell cavity with a PBG cell was designed and optimized for HOM damping. Monopole and dipole HOMs were simulated. The SRF cavity was fabricated and tuned. External quality factors for some HOMs were measured in a cold test. The measurements agreed well with the simulations.

  1. Higher order mode damping in a five-cell superconducting rf cavity with a photonic band gap coupler cell

    Directory of Open Access Journals (Sweden)

    Sergey A. Arsenyev

    2016-08-01

    Full Text Available We present a study of higher order mode (HOM damping in the first multicell superconducting radio-frequency (SRF cavity with a photonic band gap (PBG coupler cell. Achieving higher average beam currents is particularly desirable for future light sources and particle colliders based on SRF energy-recovery linacs (ERLs. Beam current in ERLs is limited by the beam breakup instability, caused by parasitic HOMs interacting with the beam in accelerating cavities. A PBG cell incorporated in an accelerating cavity can reduce the negative effect of HOMs by providing a frequency selective damping mechanism, thus allowing significantly higher beam currents. The five-cell cavity with a PBG cell was designed and optimized for HOM damping. Monopole and dipole HOMs were simulated. The SRF cavity was fabricated and tuned. External quality factors for some HOMs were measured in a cold test. The measurements agreed well with the simulations.

  2. The RF Design of an HOM Polarized RF Gun for the ILC

    International Nuclear Information System (INIS)

    Wang, J.W.; Clendenin, J.E.; Colby, E.R.; Miller, R.A.; Lewellen, J.W.

    2006-01-01

    The ILC requires a polarized electron beam. While a highly polarized beam can be produced by a GaAs-type cathode in a DC gun of the type currently in use at SLAC, JLAB and elsewhere, the ILC injector system can be simplified and made more efficient if a GaAs-type cathode can be combined with a low emittance RF gun. Since this type of cathode is known to be extremely sensitive to vacuum contamination including back bombardment by electrons and ions, any successful polarized RF gun must have a significantly improved operating vacuum compared to existing RF guns. We present a new RF design for an L-Band normal conducting (NC) RF gun for the ILC polarized electron source. This design incorporates a higher order mode (HOM) structure, whose chief virtue in this application is an improved conductance for vacuum pumping on the cathode. Computer simulation models have been used to optimize the RF parameters with two principal goals: first to minimize the required RF power; second to reduce the peak surface field relative to the field at the cathode in order to suppress field emitted electron bombardment. The beam properties have been simulated initially using PARMELA. Vacuum and other practical issues for implementing this design are discussed

  3. Design of Dual-Band Two-Branch-Line Couplers with Arbitrary Coupling Coefficients in Bands

    Directory of Open Access Journals (Sweden)

    I. Prudyus

    2014-12-01

    Full Text Available A new approach to design dual-band two-branch couplers with arbitrary coupling coefficients at two operating frequency bands is proposed in this article. The method is based on the usage of equivalent subcircuits input reactances of the even-mode and odd-mode excitations. The exact design formulas for three options of the dual-band coupler with different location and number of stubs are received. These formulas permit to obtain the different variants for each structure in order to select the physically realizable solution and can be used in broad range of frequency ratio and power division ratio. For verification, three different dual-band couplers, which are operating at 2.4/3.9 GHz with different coupling coefficients (one with 3/6 dB, and 10/3 dB two others are designed, simulated, fabricated and tested. The measured results are in good agreement with the simulated ones.

  4. RF Coupler Design for the TRIUMF ISAC-II Superconducting Quarter Wave Resonator

    CERN Document Server

    Poirier, R L; Harmer, P; Laxdal, R E; Mitra, A K; Sekatchev, I; Waraich, B; Zvyagintsev, V

    2004-01-01

    An RF Coupler for the ISAC-II medium beta (β=0.058 and 0.071) superconducting quarter wave resonators was designed and tested at TRIUMF. The main goal of this development was to achieve stable operation of superconducting cavities at high acceleration gradients and low thermal load to the helium refrigeration system. The cavities will operate at 6 MV/m acceleration gradient in overcoupled mode at a forward power 200 W at 106 MHz. The overcoupling provides ±20 Hz cavity bandwidth, which improves the stability of the RF control system for fast helium pressure fluctuations, microphonics and environmental noise. Choice of materials, cooling with liquid nitrogen, aluminum nitride RF window and thermal shields insure a small thermal load on the helium refrigeration system by the Coupler. An RF finger contact which causedμdust in the coupler housing was eliminated without any degradation of the coupler performance. RF and thermal calculations, design and test results on the coupler are p...

  5. Cost-Effectiveness Comparison of Coupler Designs of Wireless Power Transfer for Electric Vehicle Dynamic Charging

    Directory of Open Access Journals (Sweden)

    Weitong Chen

    2016-11-01

    Full Text Available This paper presents a cost-effectiveness comparison of coupler designs for wireless power transfer (WPT, meant for electric vehicle (EV dynamic charging. The design comparison of three common types of couplers is first based on the raw material cost, output power, transfer efficiency, tolerance of horizontal offset, and flux density. Then, the optimal cost-effectiveness combination is selected for EV dynamic charging. The corresponding performances of the proposed charging system are compared and analyzed by both simulation and experimentation. The results verify the validity of the proposed dynamic charging system for EVs.

  6. HOM characterization for beam diagnostics at the european XFEL injector

    CERN Document Server

    Baboi, Nicoletta; Shi, Liangliang; Wamsat, Thomas, DESY; Jones, Roger M; Joshi, Nirav

    2017-01-01

    Higher Order Modes (HOM) excited by bunched electron beams in accelerating cavities carry information about the beam position and phase. This principle is used at the FLASH facility, at DESY, for beam position monitoring in 1.3 and 3.9 GHz cavities. Dipole modes, which depend on the beam offset, are used. Similar monitors are now under design for the European XFEL. In addition to beam position, the beam phase with respect to the accelerating RF will be monitored using monopole modes from the first higher order monopole band. The HOM signals are available from two couplers installed on each cavity. Their monitoring will allow the on-line tracking of the phase stability over time, and we anticipate that it will improve the stability of the facility. As part of the monitor designing, the HOM spectra in the cavities of the 1.3 and 3.9 GHz cryo-modules installed in the European XFEL injector have been measured. This paper will present their dependence on the beam position. The variation in the modal distribution f...

  7. Flat-Passband 3 × 3 Interleaving Filter Designed With Optical Directional Couplers in Lattice Structure

    Science.gov (United States)

    Wang, Qi Jie; Zhang, Ying; Soh, Yeng Chai

    2005-12-01

    This paper presents a novel lattice optical delay-line circuit using 3 × 3 directional couplers to implement three-port optical interleaving filters. It is shown that the proposed circuit can deliver three channels of 2pi/3 phase-shifted interleaving transmission spectra if the coupling ratios of the last two directional couplers are selected appropriately. The other performance requirements of an optical interleaver can be achieved by designing the remaining part of the lattice circuit. A recursive synthesis design algorithm is developed to calculate the design parameters of the lattice circuit that will yield the desired filter response. As illustrative examples, interleavers with maximally flat-top passband transmission and with given transmission performance on passband ripples and passband bandwidth, respectively, are designed to verify the effectiveness of the proposed design scheme.

  8. Design and optimization of mechanically down-doped terahertz fiber directional couplers

    DEFF Research Database (Denmark)

    Bao, Hualong; Nielsen, Kristian; Rasmussen, Henrik K.

    2014-01-01

    We present a thorough practical design optimization of broadband low loss, terahertz (THz) photonic crystal fiber directional couplers in which the two cores are mechanically down-doped with a triangular array of air holes. A figure of merit taking both the 3-dB bandwidth and loss of the coupler...... into account, is used for optimization of the structure parameters, given by the diameter and pitch of the cladding (d and Λ) and of the core (dc and Λc) air-hole structure. The coupler with Λ = 498.7 μm, dc= 324.2 μm, Λc = 74.8 μm, and dc = 32.5 μm is found to have the best performance at a center frequency...... of 1THz, with a bandwidth of 0.25 THz and a total device loss of 9.2 dB. The robustness of the optimum coupler to structural changes is investigated. © 2014 Optical Society of America....

  9. The Design of Polymer Planar Optical Triplexer with MMI Filter and Directional Coupler

    Directory of Open Access Journals (Sweden)

    V. Jerabek

    2013-12-01

    Full Text Available Optical bidirectional WDM transceiver is a key component of the Passive Optical Network of the Fiber to the Home topology. Essential parts of such transceivers are filters that combine multiplexing and demultiplexing function of optical signal (triplexing filters. In this paper we report about a design of a new planar optical multi-wavelength selective system triplexing filter, which combines a multimode interference filter with directional coupler based on the epoxy polymer SU-8 on Si/SiO2 substrate. The optical triplexing filter was designed using the Beam Propagation Method. The aim of this project was to optimize the triplexing filter optical parameters and to minimize the planar optical wavelength selective system dimensions. The multimode interference filter was used for separation of downstream optical signal in designed optoelectronic integrated WDM transceiver. The directional coupler was used for adding of upstream optical signal.

  10. Ceramic Power Extractor Design at 15.6 GHz

    CERN Document Server

    Smirnov, Alexei Yu; Yi, Rong; Yu, David

    2005-01-01

    Power extractor and coupler designs developed for an experiment planned at the 12th beam harmonic of the upgraded Advanced Wakefield Accelerator (AWA) facility is described. New features are an upstream HOM dielectric damper with additional tapering, and a single-port coupler considered in two variants. Performance analysis includes coupler geometric tolerances, overvoltage, dipole mode wake and BBU; and wakefield losses induced in the damper.

  11. Comparison of coaxial higher order mode couplers for the CERN Superconducting Proton Linac study

    Directory of Open Access Journals (Sweden)

    K. Papke

    2017-06-01

    Full Text Available Higher order modes (HOMs may affect beam stability and refrigeration requirements of superconducting proton linacs such as the Superconducting Proton Linac, which is studied at CERN. Under certain conditions beam-induced HOMs can accumulate sufficient energy to destabilize the beam or quench the superconducting cavities. In order to limit these effects, CERN considers the use of coaxial HOM couplers on the cutoff tubes of the 5-cell superconducting cavities. These couplers consist of resonant antennas shaped as loops or probes, which are designed to couple to potentially dangerous modes while sufficiently rejecting the fundamental mode. In this paper, the design process is presented and a comparison is made between various designs for the high-beta SPL cavities, which operate at 704.4 MHz. The rf and thermal behavior as well as mechanical aspects are discussed. In order to verify the designs, a rapid prototype for the favored coupler was fabricated and characterized on a low-power test-stand.

  12. Hom-Novikov algebras

    International Nuclear Information System (INIS)

    Yau, Donald

    2011-01-01

    We study a twisted generalization of Novikov algebras, called Hom-Novikov algebras, in which the two defining identities are twisted by a linear map. It is shown that Hom-Novikov algebras can be obtained from Novikov algebras by twisting along any algebra endomorphism. All algebra endomorphisms on complex Novikov algebras of dimensions 2 or 3 are computed, and their associated Hom-Novikov algebras are described explicitly. Another class of Hom-Novikov algebras is constructed from Hom-commutative algebras together with a derivation, generalizing a construction due to Dorfman and Gel'fand. Two other classes of Hom-Novikov algebras are constructed from Hom-Lie algebras together with a suitable linear endomorphism, generalizing a construction due to Bai and Meng.

  13. Conceptual design of a sapphire loaded coupler for superconducting radio-frequency 1.3 GHz cavities

    Science.gov (United States)

    Xu, Chen; Tantawi, Sami

    2016-02-01

    This paper explores a hybrid mode rf structure that served as a superconducting radio-frequency coupler. This application achieves a reflection S(1 ,1 ) varying from 0 to -30 db and delivers cw power at 7 KW. The coupler has good thermal isolation between the 2 and 300 K sections due to vacuum separation. Only one single hybrid mode can propagate through each section, and no higher order mode is coupled. The analytical and numerical analysis for this coupler is given and the design is optimized. The coupling mechanism to the cavity is also discussed.

  14. Conceptual design of a sapphire loaded coupler for superconducting radio-frequency 1.3 GHz cavities

    Directory of Open Access Journals (Sweden)

    Chen Xu

    2016-02-01

    Full Text Available This paper explores a hybrid mode rf structure that served as a superconducting radio-frequency coupler. This application achieves a reflection S_{(1,1} varying from 0 to −30  db and delivers cw power at 7 KW. The coupler has good thermal isolation between the 2 and 300 K sections due to vacuum separation. Only one single hybrid mode can propagate through each section, and no higher order mode is coupled. The analytical and numerical analysis for this coupler is given and the design is optimized. The coupling mechanism to the cavity is also discussed.

  15. Design and fabrication of three-dimensional polymer mode multiplexer based on asymmetric waveguide couplers

    Science.gov (United States)

    He, Guobing; Gao, Yang; Xu, Yan; Ji, Lanting; Sun, Xiaoqiang; Wang, Xibin; Yi, Yunji; Chen, Changming; Wang, Fei; Zhang, Daming; Wu, Yuanda

    2018-05-01

    A polymer mode multiplexer based on asymmetric couplers is theoretically designed and experimentally demonstrated. The proposed X-junction coupler is formed by waveguides overlapped with different crossing angles in the vertical direction. A beam propagation method is adopted to optimize the dimensional parameters of the mode multiplexer to convert LP01 mode of two lower waveguides to LP11a and LP21a mode of the upper waveguide. The ultraviolet lithography and wet chemical etching are used in the fabrication process. A conversion ratio over 98% for both LP11a and LP21a mode in the wavelength range from 1530 to 1570 nm are experimentally demonstrated. This mode multiplexer has potential in broadband mode-division multiplexing transmission systems.

  16. Design of a compact polarization beam splitter based on a deformed photonic crystal directional coupler

    International Nuclear Information System (INIS)

    Ren Gang; Zheng Wanhua; Wang Ke; Du Xiaoyu; Xing Mingxin; Chen Lianghui

    2008-01-01

    In this paper a compact polarization beam splitter based on a deformed photonic crystal directional coupler is designed and simulated. The transverse-electric (TE) guided mode and transverse-magnetic (TM) guided mode are split due to different guiding mechanisms. The effect of the shape deformation of the air holes on the coupler is studied. It discovered that the coupling strength of the coupled waveguides is strongly enhanced by introducing elliptical airholes, which reduce the device length to less than 18.5μm. A finite-difference time-domain simulation is performed to evaluate the performance of the device, and the extinction ratios for both TE and TM polarized light are higher than 20 dB. (classical areas of phenomenology)

  17. New design of a triplexer using ring resonator integrated with directional coupler based on photonic crystals

    Science.gov (United States)

    Wu, Yaw-Dong; Shih, Tien-Tsorng; Lee, Jian-Jang

    2009-11-01

    In this paper, we proposed the design of directional coupler integrated with ring resonator based on two-dimensional photonic crystals (2D PCs) to develop a triplexer filter. It can be widely used as the fiber access network element for multiplexer-demultiplexer wavelength selective in fiber-to-the-home (FTTH) communication systems. The directional coupler is chosen to separate the wavelengths of 1490nm and 1310nm. The ring resonator separates the wavelength of 1550nm. The transmission efficiency is larger than 90%. Besides, the total size of propose triplexer is only 19μm×12μm. We present simulation results using the finite-difference time-domain (FDTD) method for the proposed structure.

  18. Magnetic Shielding Design for Coupler of Wireless Electric Vehicle Charging Using Finite Element Analysis

    Science.gov (United States)

    Zhao, W. N.; Yang, X. J.; Yao, C.; Ma, D. G.; Tang, H. J.

    2017-10-01

    Inductive power transfer (IPT) is a practical and preferable method for wireless electric vehicle (EV) charging which proved to be safe, convenient and reliable. Due to the air gap between the magnetic coupler, the magnetic field coupling decreases and the magnetic leakage increases significantly compared to traditional transformer, and this may lead to the magnetic flux density around the coupler more than the safety limit for human. So magnetic shielding should be adding to the winding made from litz wire to enhance the magnetic field coupling effect in the working area and reduce magnetic field strength in non-working area. Magnetic shielding can be achieved by adding high-permeability material or high-conductivity material. For high-permeability material its magnetic reluctance is much lower than the surrounding air medium so most of the magnetic line goes through the high-permeability material rather than surrounding air. For high-conductivity material the eddy current in the material can produce reverse magnetic field to achieve magnetic shielding. This paper studies the effect of the two types of shielding material on coupler for wireless EV charging and designs combination shielding made from high-permeability material and high-conductivity material. The investigation of the paper is done with the help of finite element analysis.

  19. Design and Analysis of an Optical Coupler for Concentrated Solar Light Using Optical Fibers in Residential Buildings

    Directory of Open Access Journals (Sweden)

    Afshin Aslian

    2016-01-01

    Full Text Available Concentrated sunlight that is transmitted by fiber optics has been used for generating electricity, heat, and daylight. On the other hand, multijunction photovoltaic cells provide high efficiency for generating electricity from highly concentrated sunlight. This study deals with designing and simulating a high-efficiency coupler, employing a mathematical model to connect sunlight with fiber optics for multiple applications. The coupler concentrates and distributes irradiated light from a primary concentrator. In this study, a parabolic dish was used as the primary concentrator, a coupler that contains nine components called a compound truncated pyramid and a cone (CTPC, all of which were mounted on a plate. The material of both the CTPC and the plate was BK7 optical glass. Fiber optics cables and multijunction photovoltaic cells were connected to the cylindrical part of the CTPC. The fibers would transmit the light to the building to provide heat and daylight, whereas multijunction photovoltaic cells generate electricity. Theoretical and simulation results showed high performance of the designed coupler. The efficiency of the coupler was as high as 92%, whereas the rim angle of the dish increased to an optimum angle. Distributed sunlight in the coupler increased the flexibility and simplicity of the design, resulting in a system that provided concentrated electricity, heat, and lighting for residential buildings.

  20. Next generation HOM-damping

    Science.gov (United States)

    Marhauser, Frank

    2017-06-01

    Research and development for superconducting radio-frequency cavities has made enormous progress over the last decades from the understanding of theoretical limitations to the industrial mass fabrication of cavities for large-scale particle accelerators. Key technologies remain hot topics due to continuously growing demands on cavity performance, particularly when in pursuit of high quality beams at higher beam currents or higher luminosities than currently achievable. This relates to higher order mode (HOM) damping requirements. Meeting the desired beam properties implies avoiding coupled multi-bunch or beam break-up instabilities depending on the machine and beam parameters that will set the acceptable cavity impedance thresholds. The use of cavity HOM-dampers is crucial to absorb the wakefields, comprised by all beam-induced cavity Eigenmodes, to beam-dynamically safe levels and to reduce the heat load at cryogenic temperature. Cavity damping concepts may vary, but are principally based on coaxial and waveguide couplers as well as beam line absorbers or any combination. Next generation energy recovery linacs and circular colliders call for cavities with strong HOM-damping that can exceed the state-of-the-art, while the operating mode efficiency shall not be significantly compromised concurrently. This imposes major challenges given the rather limited damping concepts. A detailed survey of established cavities is provided scrutinizing the achieved damping performance, shortcomings, and potential improvements. The scaling of the highest passband mode impedances is numerically evaluated in dependence on the number of cells for a single-cell up to a nine-cell cavity, which reveals the increased probability of trapped modes. This is followed by simulations for single-cell and five-cell cavities, which incorporate multiple damping schemes to assess the most efficient concepts. The usage and viability of on-cell dampers is elucidated for the single-cell cavity since it

  1. Electronics and Algorithms for HOM Based Beam Diagnostics

    Science.gov (United States)

    Frisch, Josef; Baboi, Nicoleta; Eddy, Nathan; Nagaitsev, Sergei; Hensler, Olaf; McCormick, Douglas; May, Justin; Molloy, Stephen; Napoly, Olivier; Paparella, Rita; Petrosyan, Lyudvig; Ross, Marc; Simon, Claire; Smith, Tonee

    2006-11-01

    The signals from the Higher Order Mode (HOM) ports on superconducting cavities can be used as beam position monitors and to do survey structure alignment. A HOM-based diagnostic system has been installed to instrument both couplers on each of the 40 cryogenic accelerating structures in the DESY TTF2 Linac. The electronics uses a single stage down conversion from the 1.7 GHz HOM spectral line to a 20MHz IF which has been digitized. The electronics is based on low cost surface mount components suitable for large scale production. The analysis of the HOM data is based on Singular Value Decomposition. The response of the OM modes is calibrated using conventional BPMs.

  2. The Prototype Fundamental Power Coupler For The Spallation Neutron Source Superconducting Cavities: Design And Initial Test Results

    International Nuclear Information System (INIS)

    K. M. Wilson; I. E. Campisi; E. F. Daly; G. K. Davis; M. Drury; J. E. Henry; P. Kneisel; G. Myneni; T. Powers; W. J. Schneider; M. Stirbet; Y. Kang; K. Cummings; T. Hardek

    2001-01-01

    Each of the 805 MHz superconducting cavities of the Spallation Neutron Source (SNS) is powered via a coaxial Fundamental Power Coupler (FPC) with a 50 Omega impedance and a warm planar alumina window. The design is derived from the experience of other laboratories; in particular, a number of details are based on the coupler developed for the KEK B-Factory superconducting cavities. However, other design features have been modified to account for the fact that the SNS FPC will transfer a considerably lower average power than the KEK-B coupler. Four prototypes have been manufactured so far, and preliminary tests performed on two of them at Los Alamos National Laboratory (LANL). During these tests, peak powers of over 500 kW were transferred through the couplers in the test stand designed and built for this purpose. This paper gives details of the coupler design and of the results obtained from the RF tests on the test stand during the last few months. A more comprehensive set of tests is planned for the near future

  3. Design of a 300 GHz Broadband TWT Coupler and RF-Structure

    CERN Document Server

    Krawczyk, F L

    2004-01-01

    Recent LANL activities in millimeter wave structures focus on 94 and 300 GHz structures. They aim at power generation from low power (100–2000 W) with a round electron beam (120 kV, 0.1–1.0 A) to high power (2–100 kW) with a sheet beam structure (120 kV, 20 A). Applications cover basic research, radar and secure communications and remote sensing of biological and chemical agents. In this presentation the design and cold-test measurements of a 300 GHz RF-structure with a broadband (>6% bandwidth) power coupler are presented. The design choice of two input/output waveguides, a special coupling region and the structure parameters themselves are presented. As a benchmark also a scaled up version at 10 GHz was designed and measured. These results will also be presented.

  4. HOM frequency control of SRF cavity in high current ERLs

    Science.gov (United States)

    Xu, Chen; Ben-Zvi, Ilan

    2018-03-01

    The acceleration of high-current beam in Superconducting Radio Frequency (SRF) cavities is a challenging but essential for a variety of advanced accelerators. SRF cavities should be carefully designed to minimize the High Order Modes (HOM) power generated in the cavities by the beam current. The reduction of HOM power we demonstrate in a particular case can be quite large. This paper presents a method to systematically control the HOM resonance frequencies in the initial design phase to minimize the HOM power generation. This method is expected to be beneficial for the design of high SRF cavities addressing a variety of Energy Recovery Linac (ERL) applications.

  5. Cryogenic cooler thermal coupler

    International Nuclear Information System (INIS)

    Green, K.E.; Talbourdet, J.A.

    1984-01-01

    A thermal coupler assembly mounted to the coldfinger of a cryogenic cooler which provides improved thermal transfer between the coldfinger and the detector assembly mounted on the dewar endwell. The thermal coupler design comprises a stud and spring-loaded cap mounted on the coldfinger assembly. Thermal transfer is made primarily through the air space between the cap and coldwell walls along the radial surfaces. The cap is spring loaded to provide thermal contact between the cap and endwell end surfaces

  6. Demountable damped cavity for HOM-damping in ILC superconducting accelerating cavities

    Energy Technology Data Exchange (ETDEWEB)

    Konomi, T., E-mail: konomi@ims.ac.jp [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Yasuda, F. [University of Tokyo, Bunkyo-ku, Tokyo 113-8654 (Japan); Furuta, F. [Laboratory for Elementary-Particle Physics, Cornell University, Ithaca, NY 14853 (United States); Saito, K. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2014-01-11

    We have designed a new higher-order-mode (HOM) damper called a demountable damped cavity (DDC) as part of the R and D efforts for the superconducting cavity of the International Linear Collider (ILC). The DDC has two design concepts. The first is an axially symmetrical layout to obtain high damping efficiency. The DDC has a coaxial structure along the beam axis to realize strong coupling with HOMs. HOMs are damped by an RF absorber at the end of the coaxial waveguide and the accelerating mode is reflected by a choke filter mounted at the entrance of the coaxial waveguide. The second design concept is a demountable structure to facilitate cleaning, in order to suppress the Q-slope problem in a high field. A single-cell cavity with the DDC was fabricated to test four performance parameters. The first was frequency matching between the accelerating cavity and the choke filter. Since the bandwidth of the resonance frequency in a superconducting cavity is very narrow, there is a possibility that the accelerating field will leak to the RF absorber because of thermal shrinkage. The design bandwidth of the choke filter is 25 kHz. It was demonstrated that frequency matching adjusted at room temperature could be successfully maintained at 2 K. The second parameter was the performance of the demountable structure. At the joint, the magnetic field is 1/6 of the maximum field in the accelerating cavity. Ultimately, the accelerating field reached 19 MV/m and Q{sub 0} was 1.5×10{sup 10} with a knife-edge shape. The third parameter was field emission and multipacting. Although the choke structure has numerous parallel surfaces that are susceptible to the multipacting problem, it was found that neither field emission nor multipacting presented problems in both an experiment and simulation. The final parameter was the Q values of the HOM. The RF absorber adopted in the system is a Ni–Zn ferrite type. The RF absorber shape was designed based on the measurement data of permittivity

  7. Demountable damped cavity for HOM-damping in ILC superconducting accelerating cavities

    International Nuclear Information System (INIS)

    Konomi, T.; Yasuda, F.; Furuta, F.; Saito, K.

    2014-01-01

    We have designed a new higher-order-mode (HOM) damper called a demountable damped cavity (DDC) as part of the R and D efforts for the superconducting cavity of the International Linear Collider (ILC). The DDC has two design concepts. The first is an axially symmetrical layout to obtain high damping efficiency. The DDC has a coaxial structure along the beam axis to realize strong coupling with HOMs. HOMs are damped by an RF absorber at the end of the coaxial waveguide and the accelerating mode is reflected by a choke filter mounted at the entrance of the coaxial waveguide. The second design concept is a demountable structure to facilitate cleaning, in order to suppress the Q-slope problem in a high field. A single-cell cavity with the DDC was fabricated to test four performance parameters. The first was frequency matching between the accelerating cavity and the choke filter. Since the bandwidth of the resonance frequency in a superconducting cavity is very narrow, there is a possibility that the accelerating field will leak to the RF absorber because of thermal shrinkage. The design bandwidth of the choke filter is 25 kHz. It was demonstrated that frequency matching adjusted at room temperature could be successfully maintained at 2 K. The second parameter was the performance of the demountable structure. At the joint, the magnetic field is 1/6 of the maximum field in the accelerating cavity. Ultimately, the accelerating field reached 19 MV/m and Q 0 was 1.5×10 10 with a knife-edge shape. The third parameter was field emission and multipacting. Although the choke structure has numerous parallel surfaces that are susceptible to the multipacting problem, it was found that neither field emission nor multipacting presented problems in both an experiment and simulation. The final parameter was the Q values of the HOM. The RF absorber adopted in the system is a Ni–Zn ferrite type. The RF absorber shape was designed based on the measurement data of permittivity and

  8. Design of a 300 GHZ broadband coupler and RF-structure

    International Nuclear Information System (INIS)

    Krawczyk, F.L.; Carlsten, B.E.; Earley, L.M.; Sigler, F.E.; Potter, J.M.; Schulze, M.E.

    2004-01-01

    Recent LANL activities in millimeter wave structures focus on 95 and 300 GHz structures. They aim at power generation from low power (100W-2kW) with a round electron beam (120kV, 0.1-1.0 A) to high power (2-100 kW) with a sheet beam structure (120 kV, 20 A). Applications cover basic research, radar and secure communications and remote sensing of biological and chemical agents. In this presentation the design of a 300 GHz RF-structure with a broadband (> 6% bandwidth) power coupler is presented. The choice of two input/output waveguides, a special coupling region and the structure parameters are presented. As a benchmark also a scaled up version at 10 GHz was designed and measured. These results will also be presented. We are investigating planar micro-fabricated traveling-wave tube amplifiers as sources for the generation of millimeter waves from 95 to 300 GHz. While for low energy applications narrow structures with pencil beams are proposed, for high energy operation flat, thin sheet beams are required. For the latter vane-loaded rectangular waveguides that operate in a slow-wave mode matched to the velocity of the electron beam are especially well suited. The 300 GHz effort initially is limited to narrow structures for pencil beams. The main emphasis for this work are the study of fabrication issues and the understanding of features that allow a broadband operation (5-10% bandwidth).

  9. Design, construction and tuning of S-band coupler for electron linear accelerator of institute for research in fundamental sciences (IPM E-linac)

    International Nuclear Information System (INIS)

    Ghasemi, F.; Abbasi Davani, F.; Lamehi Rachti, M.; Shaker, H.; Ahmadiannamin, S.

    2015-01-01

    Design and construction of an electron linear accelerator by Institute for Research in Fundamental Science (IPM) is considered as Iran’s first attempt to construct such an accelerator. In order to design a linear accelerating tube, after defining the accelerating tube and buncher geometries, RF input and output couplers must be designed. In this article, firstly, a brief report on the specifications of an S-band electron linear accelerator which is in progress in the school of particles and accelerators is presented and then, the design process and construction reports of the couplers required for this accelerator are described. Through performing necessary calculations and tuning the coupling factor and resonant frequency, couplers with desired specification have been fabricated by shrinking method. The final obtained coupling factor and resonant frequency have been respectively 1.05 and 2997 MHz for the first coupler, and 0.98 and 2996.9 MHz for the second one that are close to calculation results

  10. Design of electro-absorption modulator with tapered-mode coupler on the GeSi layer

    International Nuclear Information System (INIS)

    Li, Ym; Cheng, Bw

    2013-01-01

    A tapered-mode coupler integrated GeSi electro-absorption (EA) modulator is investigated theoretically. To improve the parameter insensitivity and modulation efficiency of the GeSi EA modulator based on evanescent coupling, a tapered coupler on the GeSi layer is introduced in our design. The two coupling mechanisms in our suggested structure are compared. Both the beam propagation method (BPM) calculation and coupling mode theory show almost 100% power transfer from the bottom rib waveguide to the GeSi layer. After a series of designs of the tapered coupler, we get a modulator with the advantages of both evanescent-coupling modulators (Feng et al 2011 Opt. Express 19 7062–7, Feng et al 2012 Opt. Express 20 22224–32, Liu et al 2008 Nature Photon. 2 433–7, Liu et al 2007 Opt. Express 15 623–8) and butt-coupling modulators (Lim et al 2011 Opt. Express 19 5040–6), that are ease of fabrication, low coupling loss, performance stability and high modulation efficiency. (paper)

  11. An analysis of multislot directional coupler

    International Nuclear Information System (INIS)

    Arai, Hiroyuki; Goto, Naohisa; Yamamoto, Takumi.

    1986-03-01

    This paper presents an analysis of multislot directional coupler for monitoring the gyrotron output. We solved the boundary value problem of the directional coupler to investigate the detailed effect of finite thickness slot and mutual coupling between slots. Numerical data of coupler design is presented for non-resonant a pair slot, and mode sensitivity in overmoded waveguide is also evaluated. (author)

  12. Mechanical design and engineering of the 3.9 GHZ, 3rd harmonic SRF system at Fermilab

    International Nuclear Information System (INIS)

    Don Mitchell

    2004-01-01

    The mechanical development of the 3.9 GHz, 3rd Harmonic SRF System is summarized to include: the development of a full scale copper prototype cavity structure; the design of the niobium 3 cell and niobium 9 cell structures; the design of the helium vessel and cryostat; the HOM coupler design; and a preliminary look at the main coupler design. The manufacturing processes for forming, rolling, and e-beam welding the HOM coupler, cavity cells, and end tubes are also described. Due to the exotic materials and manufacturing processes used in this type of device, a cost estimate for the material and fabrication is provided. The 3rd harmonic design is organized via a web-based data management approach

  13. Mechanical design and engineering of the 3.9 GHZ, 3rd harmonic SRF system at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Don Mitchell et al.

    2004-08-05

    The mechanical development of the 3.9 GHz, 3rd Harmonic SRF System is summarized to include: the development of a full scale copper prototype cavity structure; the design of the niobium 3 cell and niobium 9 cell structures; the design of the helium vessel and cryostat; the HOM coupler design; and a preliminary look at the main coupler design. The manufacturing processes for forming, rolling, and e-beam welding the HOM coupler, cavity cells, and end tubes are also described. Due to the exotic materials and manufacturing processes used in this type of device, a cost estimate for the material and fabrication is provided. The 3rd harmonic design is organized via a web-based data management approach.

  14. Waveguide silicon nitride grating coupler

    Science.gov (United States)

    Litvik, Jan; Dolnak, Ivan; Dado, Milan

    2016-12-01

    Grating couplers are one of the most used elements for coupling of light between optical fibers and photonic integrated components. Silicon-on-insulator platform provides strong confinement of light and allows high integration. In this work, using simulations we have designed a broadband silicon nitride surface grating coupler. The Fourier-eigenmode expansion and finite difference time domain methods are utilized in design optimization of grating coupler structure. The fully, single etch step grating coupler is based on a standard silicon-on-insulator wafer with 0.55 μm waveguide Si3N4 layer. The optimized structure at 1550 nm wavelength yields a peak coupling efficiency -2.6635 dB (54.16%) with a 1-dB bandwidth up to 80 nm. It is promising way for low-cost fabrication using complementary metal-oxide- semiconductor fabrication process.

  15. Design of Miniaturized 10dB Wideband Branch Line Coupler Using Dual and T-Shape Transmission Lines

    Directory of Open Access Journals (Sweden)

    M. Kumar

    2018-04-01

    Full Text Available This paper presents a design mechanism of miniaturized wideband branch line coupler (BLC with loose coupling of 10 dB. Dual transmission lines are used as a feed network which provides a size reduction of 32% with a fractional bandwidth (FBW of 60% for 10±0.5 dB coupling but return loss performance is found to be poor in the operating band. For further improvement of return loss performance as well as for size reduction of the BLC, a T- shape transmission lines are used instead of series quarter wavelength transmission lines, and hence the overall size reduction of around 44% with FBW of 50.4% is achieved. The return loss and isolation performance is found to be les than 15 dB in the entire operating band (2.5–4.1 GHz with respect to design frequency 3G Hz. The proposed BLC is analyzed, fabricated and tested.

  16. Design and length optimization of an adiabatic coupler for on-chip vertical integration of rare-earth-doped double tungstate waveguide amplifiers

    NARCIS (Netherlands)

    Mu, Jinfeng; Sefünç, Mustafa; García Blanco, Sonia Maria

    2014-01-01

    The integration of rare-earth doped double tungstate waveguide amplifiers onto passive technology platforms enables the on-chip amplification of very high bit rate signals. In this work, a methodology for the optimized design of vertical adiabatic couplers between a passive Si3N4 waveguide and the

  17. Cryogenic testing of the 2.1 GHz five-cell superconducting RF cavity with a photonic band gap coupler cell

    Science.gov (United States)

    Arsenyev, Sergey A.; Temkin, Richard J.; Haynes, W. Brian; Shchegolkov, Dmitry Yu.; Simakov, Evgenya I.; Tajima, Tsuyoshi; Boulware, Chase H.; Grimm, Terrence L.; Rogacki, Adam R.

    2016-05-01

    We present results from cryogenic tests of the multi-cell superconducting radio frequency (SRF) cavity with a photonic band gap (PBG) coupler cell. Achieving high average beam currents is particularly desirable for future light sources and particle colliders based on SRF energy-recovery-linacs (ERLs). Beam current in ERLs is limited by the beam break-up instability, caused by parasitic higher order modes (HOMs) interacting with the beam in accelerating cavities. A PBG cell incorporated in an accelerating cavity can reduce the negative effect of HOMs by providing a frequency selective damping mechanism, thus allowing significantly higher beam currents. The multi-cell cavity was designed and fabricated of niobium. Two cryogenic (vertical) tests were conducted. The high unloaded Q-factor was demonstrated at a temperature of 4.2 K at accelerating gradients up to 3 MV/m. The measured value of the unloaded Q-factor was 1.55 × 108, in agreement with prediction.

  18. HOM identification by bead pulling in the Brookhaven ERL cavity

    CERN Document Server

    Hahn, H; Jain, Puneet; Johnson, Elliott C; Xu, Wencan

    2014-01-01

    Exploratory measurements of the Brookhaven Energy Recovery Linac (ERL) cavity at superconducting temperature produced a long list of high order modes (HOMs). The niobium 5-cell cavity is terminated at each end with HOM ferrite dampers that successfully reduce the Q-factors to levels required to avoid beam break up (BBU) instabilities. However, a number of un-damped resonances with Q≥106 were found at 4 K and their mode identification forms the focus of this paper. The approach taken here consists of bead pulling on a copper (Cu) replica of the ERL cavity with dampers involving various network analyzer measurements. Several different S21 transmission measurements are used, including those taken from the fundamental input coupler to the pick-up probe across the cavity, others between beam-position monitor probes in the beam tubes, and also between probes placed into the cells. The bead pull technique suitable for HOM identification with a metallic needle or dielectric bead is detailed. This paper presents the...

  19. Design and characterization of low-loss 2D grating couplers for silicon photonics integrated circuits

    Science.gov (United States)

    Lacava, C.; Carrol, L.; Bozzola, A.; Marchetti, R.; Minzioni, P.; Cristiani, I.; Fournier, M.; Bernabe, S.; Gerace, D.; Andreani, L. C.

    2016-03-01

    We present the characterization of Silicon-on-insulator (SOI) photonic-crystal based 2D grating-couplers (2D-GCs) fabricated by CEA-Leti in the frame of the FP7 Fabulous project, which is dedicated to the realization of devices and systems for low-cost and high-performance passives-optical-networks. On the analyzed samples different test structures are present, including 2D-GC connected to another 2D-GC by different waveguides (in a Mach-Zehnder like configuration), and 2D-GC connected to two separate 2D-GCs, so as to allow a complete assessment of different parameters. Measurements were carried out using a tunable laser source operating in the extended telecom bandwidth and a fiber-based polarization controlling system at the input of device-under-test. The measured data yielded an overall fiber-to-fiber loss of 7.5 dB for the structure composed by an input 2D-GC connected to two identical 2D-GCs. This value was obtained at the peak wavelength of the grating, and the 3-dB bandwidth of the 2D-GC was assessed to be 43 nm. Assuming that the waveguide losses are negligible, so as to make a worst-case analysis, the coupling efficiency of the single 2D-GC results to be equal to -3.75 dB, constituting, to the best of our knowledge, the lowest value ever reported for a fully CMOS compatible 2D-GC. It is worth noting that both the obtained values are in good agreement with those expected by the numerical simulations performed using full 3D analysis by Lumerical FDTD-solutions.

  20. Coupler induced monopole component and its minimization in deflecting cavities

    Directory of Open Access Journals (Sweden)

    P. K. Ambattu

    2013-06-01

    Full Text Available Deflecting cavities are used in particle accelerators for the manipulation of charged particles by deflecting or crabbing (rotating them. For short deflectors, the effect of the power coupler on the deflecting field can become significant. The particular power coupler type can introduce multipole rf field components and coupler-specific wakefields. Coupler types that would normally be considered like standard on-cell coupler, waveguide coupler, or mode-launcher coupler could have one or two rf feeds. The major advantage of a dual-feed coupler is the absence of monopole and quadrupole rf field components in the deflecting structure. However, a dual-feed coupler is mechanically more complex than a typical single-feed coupler and needs a splitter. For most applications, deflecting structures are placed in regions where there is small space hence reducing the size of the structure is very desirable. This paper investigates the multipole field components of the deflecting mode in single-feed couplers and ways to overcome the effect of the monopole component on the beam. Significant advances in performance have been demonstrated. Additionally, a novel coupler design is introduced which has no monopole field component to the deflecting mode and is more compact than the conventional dual-feed coupler.

  1. Comparative Simulation Studies of Multipacting in Higher-Order-Mode Couplers of Superconducting RF Cavities

    International Nuclear Information System (INIS)

    Li, Y. M.; Liu, Kexin; Geng, Rongli

    2014-01-01

    Multipacting (MP) in higher-order-mode (HOM) couplers of the International Linear Collider (ILC) baseline cavity and the Continuous Electron Beam Accelerator Facility (CEBAF) 12 GeV upgrade cavity is studied by using the ACE3P suites, developed by the Advanced Computations Department at SLAC. For the ILC cavity HOM coupler, the simulation results show that resonant trajectories exist in three zones, corresponding to an accelerating gradient range of 0.6A-1.6 MV/m, 21A-34 MV/m, 32A-35 MV/m, and > 40MV/m, respectively. For the CEBAF 12 GeV upgrade cavity HOM coupler, resonant trajectories exist in one zone, corresponding to an accelerating gradient range of 6A-13 MV/m. Potential implications of these MP barriers are discussed in the context of future high energy pulsed as well as medium energy continuous wave (CW) accelerators based on superconducting radio frequency cavities. Frequency scaling of MPA's predicted in HOM couplers of the ILC, CBEAF upgrade, SNS and FLASH third harmonic cavity is given and found to be in good agreement with the analytical result based on the parallel plate model

  2. Comparative simulation studies of multipacting in higher-order-mode couplers of superconducting rf cavities

    Directory of Open Access Journals (Sweden)

    Y. M. Li

    2014-02-01

    Full Text Available Multipacting (MP in higher-order-mode (HOM couplers of the International Linear Collider (ILC baseline cavity and the Continuous Electron Beam Accelerator Facility (CEBAF 12 GeV upgrade cavity is studied by using the ACE3P suites, developed by the Advanced Computations Department at SLAC. For the ILC cavity HOM coupler, the simulation results show that resonant trajectories exist in three zones, corresponding to an accelerating gradient range of 0.6–1.6  MV/m, 21–34   MV/m, 32–35  MV/m and >40  MV/m, respectively. For the CEBAF 12 GeV upgrade cavity HOM coupler, resonant trajectories exist in one zone, corresponding to an accelerating gradient range of 6–13  MV/m. Potential implications of these MP barriers are discussed in the context of future high-energy pulsed as well as medium-energy continuous wave accelerators based on superconducting radio frequency cavities. Frequency scaling of MP’s predicted in HOM couplers of the ILC, CEBAF upgrade, Spallation Neutron Source (SNS, and Free-Electron Laser in Hamburg (FLASH third harmonic cavity is given and found to be in good agreement with the analytical result based on the parallel plate model.

  3. Comparative Simulation Studies of Multipacting in Higher-Order-Mode Couplers of Superconducting RF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y. M. [Peking University, Beijing (China); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Liu, Kexin [Peking University, Beijing (China); Geng, Rongli [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2014-02-01

    Multipacting (MP) in higher-order-mode (HOM) couplers of the International Linear Collider (ILC) baseline cavity and the Continuous Electron Beam Accelerator Facility (CEBAF) 12 GeV upgrade cavity is studied by using the ACE3P suites, developed by the Advanced Computations Department at SLAC. For the ILC cavity HOM coupler, the simulation results show that resonant trajectories exist in three zones, corresponding to an accelerating gradient range of 0.6-1.6 MV/m, 21-34 MV/m, 32-35 MV/m, and > 40MV/m, respectively. For the CEBAF 12 GeV upgrade cavity HOM coupler, resonant trajectories exist in one zone, corresponding to an accelerating gradient range of 6-13 MV/m. Potential implications of these MP barriers are discussed in the context of future high energy pulsed as well as medium energy continuous wave (CW) accelerators based on superconducting radio frequency cavities. Frequency scaling of MP's predicted in HOM couplers of the ILC, CBEAF upgrade, SNS and FLASH third harmonic cavity is given and found to be in good agreement with the analytical result based on the parallel plate model.

  4. BNL 56 MHz HOM Damper Prototype Fabrication at JLab

    Energy Technology Data Exchange (ETDEWEB)

    Huque, Naeem A. [Jefferson Lab., Newport News, VA (United States); Daly, Edward F. [Jefferson Lab., Newport News, VA (United States); Clemens, William A. [Jefferson Lab., Newport News, VA (United States); McIntyre, Gary T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wu, Qiong [Brookhaven National Lab. (BNL), Upton, NY (United States); Seberg, Scott [Brookhaven National Lab. (BNL), Upton, NY (United States); Bellavia, Steve [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-09-01

    A prototype Higher-Order Mode (HOM) Damper was fabricated at JLab for the Relativistic Heavy-Ion Collider's (RHIC) 56 MHz cavity at Brookhaven National Laboratory (BNL). Primarily constructed from high RRR Niobium and Sapphire, the coaxial damper presented significant challenges in electron-beam welding (EBW), brazing and machining via acid etching. The results of the prototype operation brought about changes in the damper design, due to overheating braze alloys and possible multi-pacting. Five production HOM dampers are currently being fabricated at JLab. This paper outlines the challenges faced in the fabrication process, and the solutions put in place.

  5. rf coupler technology for fusion applications

    International Nuclear Information System (INIS)

    Hoffman, D.J.

    1983-01-01

    Radio frequency (rf) oscillations at critical frequencies have successfully provided a means to convey power to fusion plasmas due to the electrical-magnetic properties of the plasma. While large rf systems to couple power to the plasma have been designed, built, and tested, the main link to the plasma, the coupler, is still in an evolutionary stage of development. Design and fabrication of optimal antennas for fusion applications are complicated by incomplete characterizations of the harsh plasma environment and of coupling mechanisms. A brief description of rf coupler technology required for plasma conditions is presented along with an assessment of the status and goals of coupler development

  6. Polarization converted coupler for plasma current drive experiments

    International Nuclear Information System (INIS)

    Arai, H.; Shimizu, S.; Goto, N.

    1986-01-01

    In this paper, the authors propose the polarization converted coupler which has narrow width shape and radiates electric field perpendicular to the main toroidal magnetic field. The advantages of the polarization converted coupler are as follows: (l) The rectangular waveguide as the transmission line has the high power capability. (2) The all metal design is not damaged by the fusion neutron. (3) The characteristic of this coupler is not changed widely, since the coupler has the matching section. For example, the VSWR of its input impedance is less than 2.0 for both water and air load. The authors present characteristics of the polarization converted coupler measured by the model experiments

  7. Mechanical design considerations of a standing wave s-band accelerator with on-axis couplers

    International Nuclear Information System (INIS)

    Hodge, S.B.; Funk, L.W.; Schriber, S.O.

    1976-01-01

    The mechanical design of S-band standing wave accelerator structures with on-axis coupling cells includes material selection, cavity design, segment production, rf tuning and brazing procedures. Pre-assembly tuning operations have been minimized by determining segment dimensions and tolerances so that segments can easily be fabricated in a near-finished condition by a commercial machining firm. Final tuning, if necessary, is easily achieved by removal of material from the cavity wall or drift tube nose. Considerations in choosing brazing procedures were vacuum integrity, resistivity of brazing alloy, joint thickness, alignment of the structure assembly and restriction of grain growth. (author)

  8. A Tandem Coupler for Terahertz Integrated Circuits

    Science.gov (United States)

    Reck, Theodore J.; Deal, William; Chattopadhyay, Goutam

    2013-01-01

    A coplanar waveguide 3 dB quadrature coupler operating from 500 to 700 GHz is designed, fabricated and measured. On-wafer measurements demonstrate an amplitude balance of +/-2 dB and phase balance of +/-20 deg.

  9. Fabrication of LD-3 Polymer Directional Couplers

    National Research Council Canada - National Science Library

    Chen, Ray T

    1998-01-01

    .... LD-3 polymer directional couplers arc designed and fabricated to operate at 1.3 microns. Waveguide propagation losses, device characterization, demonstration of cross coupling and packaged device pictures are presented in this final report.

  10. Design of a hybrid silicon-plasmonic co-propagating coupler operating close to coherent perfect absorption

    Energy Technology Data Exchange (ETDEWEB)

    Zanotto, Simone; Melloni, Andrea [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2016-04-28

    By hybrid integration of plasmonic and dielectric waveguide concepts, it is shown that nearly perfect coherent absorption can be achieved in a co-propagating coupler geometry. First, the operating principle of the proposed device is detailed in the context of a more general 2 × 2 lossy coupler formalism. Then, it is shown how to tune the device in a wide region of possible working points, its broadband operation, and the tolerance to fabrication uncertainties. Finally, a complete picture of the electromagnetic modes inside the hybrid structure is analyzed, shining light onto the potentials which the proposed device holds in view of classical and quantum signal processing, nonlinear optics, polarization control, and sensing.

  11. Transverse emittance dilution due to coupler kicks in linear accelerators

    Directory of Open Access Journals (Sweden)

    Brandon Buckley

    2007-11-01

    Full Text Available One of the main concerns in the design of low emittance linear accelerators (linacs is the preservation of beam emittance. Here we discuss one possible source of emittance dilution, the coupler kick, due to transverse electromagnetic fields in the accelerating cavities of the linac caused by the power coupler geometry. In addition to emittance growth, the coupler kick also produces orbit distortions. It is common wisdom that emittance growth from coupler kicks can be strongly reduced by using two couplers per cavity mounted opposite each other or by having the couplers of successive cavities alternate from above to below the beam pipe so as to cancel each individual kick. While this is correct, including two couplers per cavity or alternating the coupler location requires large technical changes and increased cost for superconducting cryomodules where cryogenic pipes are arranged parallel to a string of several cavities. We therefore analyze consequences of alternate coupler placements. We show here that alternating the coupler location from above to below compensates the emittance growth as well as the orbit distortions. For sufficiently large Q values, alternating the coupler location from before to after the cavity leads to a cancellation of the orbit distortion but not of the emittance growth, whereas alternating the coupler location from before and above to behind and below the cavity cancels the emittance growth but not the orbit distortion. We show that cancellations hold for sufficiently large Q values. These compensations hold even when each cavity is individually detuned, e.g., by microphonics. Another effective method for reducing coupler kicks that is studied is the optimization of the phase of the coupler kick so as to minimize the effects on emittance from each coupler. This technique is independent of the coupler geometry but relies on operating on crest. A final technique studied is symmetrization of the cavity geometry in the

  12. MAFIA simulation and cold model test of three types of bridge coupler

    International Nuclear Information System (INIS)

    Chang, C.R.; Yao, C.G.; Swenson, D.A.; Funk, L.W.; Raparia, D.

    1992-01-01

    In the new design of the SSC CCL, the total number of bridge couplers has increased from 50 to 63, and their maximum length increased from 37.2 to 46.1 cm. Choosing a bridge coupler that gives maximum coupling, minimum power flow, phase shift and fabrication cost becomes important. The conventional TM010 single cavity bridge coupler used in LAMPF and Fermilab will have severe mode mixing problem when the bridge length is over 30 cm, and the coupling is very weak. Three types of bridge coupler have been proposed: (1) TM012 single cavity bridge coupler; (2) electrically coupled multi-cavity bridge coupler and (3) magnetically coupled multi-cavity bridge coupler. This paper presents both MAFIA simulations and cold model tests results. Each bridge coupler has its unique characteristics with advantages and disadvantages, but all three are superior to the conventional coupler. (Author) 6 figs., tab., 2 refs

  13. Requirements for longitudinal HOM damping in superconducting recirculating linacs

    International Nuclear Information System (INIS)

    Bisognano, J.J.; Fripp, M.L.

    1989-01-01

    Transverse beam breakup provides the primary current limitation in the operation of superconducting recirculating linacs and requires the significant damping of transverse-deflecting higher order modes. The need to damp the coexisting longitudinal HOMs in these nominally isochronous machines, however, is not as clear. Isochronicity implies that energy variations induced by excitation of longitudinal modes do not translate directly into position and current modulations. Such modulations, if present, could enhance the initial excitation, effectively closing a potentially unstable feedback loop. Design optimization of cavity structures may suggest that no longitudinal damping be provided. On the other hand, easing of the isochronicity requirement may provide desired flexibility in lattice design. In this note, limits are placed on the requirements for longitudinal HOM damping and on the tolerances for isochronicity which are driven by possible longitudinal multipass phenomena. 2 refs., 1 fig

  14. Design and numerical optimization of a mode multiplexer based on few-mode fiber couplers

    International Nuclear Information System (INIS)

    Xie, Yiwei; Fu, Songnian; Liu, Hai; Zhang, Hailiang; Tang, Ming; Liu, Deming; Shum, P

    2013-01-01

    Mode division multiplexing (MDM) transmission based on few-mode fibers (FMFs) appears to be an alternative solution for overcoming the capacity limit of single-mode fibers (SMFs). A FMF coupler-based mode division multiplexer/demultiplexer (MMUX/DeMMUX) is proposed and theoretically investigated after the fabricated FMF is characterized. MMUXs/DeMMUXs with a mode contrast ratio (MCR) of more than 20 dB can be obtained for two-mode multiplexing and three-mode multiplexing over a wavelength span of 60 and 10 nm, respectively. We numerically verify the proposed MMUX/DeMMUX which has the advantages of high MCR, easy fabrication and maintenance, and low wavelength dependence. (paper)

  15. Optimized Ultrawideband and Uniplanar Minkowski Fractal Branch Line Coupler

    Directory of Open Access Journals (Sweden)

    Mohammad Jahanbakht

    2012-01-01

    Full Text Available The non-Euclidean Minkowski fractal geometry is used in design, optimization, and fabrication of an ultrawideband (UWB branch line coupler. Self-similarities of the fractal geometries make them act like an infinite length in a finite area. This property creates a smaller design with broader bandwidth. The designed 3 dB microstrip coupler has a single layer and uniplanar platform with quite easy fabrication process. This optimized 180° coupler also shows a perfect isolation and insertion loss over the UWB frequency range of 3.1–10.6 GHz.

  16. Design of the 1.5 MW, 30-96 MHz ultra-wideband 3 dB high power hybrid coupler for Ion Cyclotron Resonance Frequency (ICRF) heating in fusion grade reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Rana Pratap, E-mail: ranayadav97@gmail.com; Kumar, Sunil; Kulkarni, S. V. [Thapar University, Patiala, Punjab 147004, India and Institute for Plasma Research, Gandhinagar 382428 (India)

    2016-01-15

    Design and developmental procedure of strip-line based 1.5 MW, 30-96 MHz, ultra-wideband high power 3 dB hybrid coupler has been presented and its applicability in ion cyclotron resonance heating (ICRH) in tokamak is discussed. For the high power handling capability, spacing between conductors and ground need to very high. Hence other structural parameters like strip-width, strip thickness coupling gap, and junction also become large which can be gone upto optimum limit where various constrains like fabrication tolerance, discontinuities, and excitation of higher TE and TM modes become prominent and significantly deteriorates the desired parameters of the coupled lines system. In designed hybrid coupler, two 8.34 dB coupled lines are connected in tandem to get desired coupling of 3 dB and air is used as dielectric. The spacing between ground and conductors are taken as 0.164 m for 1.5 MW power handling capability. To have the desired spacing, each of 8.34 dB segments are designed with inner dimension of 3.6 × 1.0 × 40 cm where constraints have been significantly realized, compensated, and applied in designing of 1.5 MW hybrid coupler and presented in paper.

  17. Fundamental Power Couplers for Superconducting Cavities

    International Nuclear Information System (INIS)

    Isidoro E. Campisi

    2001-01-01

    Fundamental power couplers (FPC's) for superconducting cavities must meet very strict requirements to perform at high power levels (hundreds of kilowatts) and in a variety of conditions (CS, pulsed, travelling wave, standing wave) without adversely affecting the performance of the cavities they are powering. Producing good coupler designs and achieving operational performances in accelerator environments are challenging tasks that have traditionally involved large resources from many laboratories. The designs involve state-of-the-art activities in RF, cryogenic and mechanical engineering, materials science, vacuum technology, and electromagnetic field modeling. Handling, assembly and conditioning procedures have been developed to achieve ever-increasing power levels and more reliable operation. In this paper, the technical issues associated with the design, construction, assembly, processing, and operation of FPC's will be reviewed, together with the progress in FPC activities in several laboratories during the past few years

  18. rf coaxial couplers for high-intensity linear accelerators

    International Nuclear Information System (INIS)

    Manca, J.J.; Knapp, E.A.

    1980-02-01

    Two rf coaxial couplers that are particularly suitable for intertank connection of the disk-and-washer accelerating structure for use in high-intensity linear accelerators have been developed. These devices have very high coupling to the accelerating structure and very low rf power loss at the operating frequency, and they can be designed for any relative particle velocity β > 0.4. Focusing and monitoring devices can be located inside these couplers

  19. Higher Order Modes HOM___s in Coupled Cavities of the Flash Module ACC39

    Energy Technology Data Exchange (ETDEWEB)

    Shinton, I.R.R.; /Manchester U. /Cockcroft Inst. Accel. Sci. Tech.; Jones, R.M.; /Manchester U. /DESY; Li, Z.; /SLAC; Zhang, P.; /Manchester U. /Cockcroft Inst. Accel. Sci. Tech. /DESY

    2012-09-14

    We analyse the higher order modes (HOM's) in the 3.9GHz bunch shaping cavities installed in the FLASH facility at DESY. A suite of finite element computer codes (including HFSS and ACE3P) and globalised scattering matrix calculations (GSM) are used to investigate the modes in these cavities. This study is primarily focused on the dipole component of the multiband expansion of the wakefield, with the emphasis being on the development of a HOM-based BPM system for ACC39. Coupled inter-cavity modes are simulated together with a limited band of trapped modes.

  20. Substrate integrated waveguide (SIW 3 dB coupler for K-Band applications

    Directory of Open Access Journals (Sweden)

    Khalid Nurehansafwanah

    2017-01-01

    Full Text Available This paper presented a designed coupler by using Rogers RO4003C with thickness (h 0.508 mm and relative permittivity (εr 3.55. The four port network coupler operates in K-band (18-27 GHz and design by using substrate integrated waveguide (SIW method. The reflection coefficient and isolation coefficient of propose Substrate Integrated Waveguide (SIW coupler is below than -10 dB. Meanwhile the coupler requirements are phase shift 90° between coupled port and output. SIW are high performance broadband interconnects with excellent immunity to electromagnetic interference and suitable for use in microwave and communication electronics, as well as increase bandwidth systems. The designs of coupler are investigated using CST Microwave Studio simulation tool. This proposed couplers are varied from parameters that cover the frequency range (21 -24 GHz and better performance of scattering (S-parameter.

  1. Design of an rf quadrupole for Landau damping

    Science.gov (United States)

    Papke, K.; Grudiev, A.

    2017-08-01

    The recently proposed superconducting quadrupole resonator for Landau damping in accelerators is subjected to a detailed design study. The optimization process of two different cavity types is presented following the requirements of the High Luminosity Large Hadron Collider (HL-LHC) with the main focus on quadrupolar strength, surface peak fields, and impedance. The lower order and higher order mode (LOM and HOM) spectrum of the optimized cavities is investigated and different approaches for their damping are proposed. On the basis of an example the first two higher order multipole errors are calculated. Likewise on this example the required rf power and optimal external quality factor for the input coupler is derived.

  2. Disease association with two Helicobacter pylori duplicate outer membrane protein genes, homB and homA.

    Science.gov (United States)

    Oleastro, Monica; Cordeiro, Rita; Yamaoka, Yoshio; Queiroz, Dulciene; Mégraud, Francis; Monteiro, Lurdes; Ménard, Armelle

    2009-06-22

    homB encodes a Helicobacter pylori outer membrane protein. This gene was previously associated with peptic ulcer disease (PUD) and was shown to induce activation of interleukin-8 secretion in vitro, as well as contributing to bacterial adherence. Its 90%-similar gene, homA, was previously correlated with gastritis. The present study aimed to evaluate the gastric disease association with homB and homA, as well as with the H. pylori virulence factors cagA, babA and vacA, in 415 H. pylori strains isolated from patients from East Asian and Western countries. The correlation among these genotypes was also evaluated. Both homB and homA genes were heterogeneously distributed worldwide, with a marked difference between East Asian and Western strains. In Western strains (n = 234, 124 PUD and 110 non-ulcer dyspepsia (NUD), homB, cagA and vacA s1 were all significantly associated with PUD (p = 0.025, p = 0.014, p = 0.039, respectively), and homA was closely correlated with NUD (p = 0.072). In East Asian strains (n = 138, 73 PUD and 65 NUD), homB was found more frequently than homA, and none of these genes was associated with the clinical outcome. Overall, homB was associated with the presence of cagA (p = 0.043) and vacA s1 (p homA was found more frequently in cagA-negative (p = 0.062) and vacA s2 (p homA copy number were observed, with a clear geographical specificity, suggesting an involvement of these genes in host adaptation. A correlation between the homB two-copy genotype and PUD was also observed, emphasizing the role of homB in the virulence of the strain. The global results suggest that homB and homA contribute to the determination of clinical outcome.

  3. Development of the SCRF Power Coupler for the APT Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Schmierer, E.N.; Lujan, R.E.; Rusnak, B.; Smith, B.; Haynes, W.B.; Gautier, C.; Waynert, J.A.; Krawczyk, F.; Gioia, J.

    1999-03-01

    The team responsible for the design of the Accelerator Production of Tritium (APT) superconducting (SC) radio frequency (RF) power coupler has developed two 700-MHz, helium gas-cooled power couplers. One has a fixed inner conductor and the other has an adjustable inner conductor (gamma prototype and alpha prototype). The power couplers will be performance tested in the near future. This paper discusses the mechanical design and fabrication techniques employed in the development of each power coupler. This includes material selection, copper coating, assembly sequences, and metal joining procedures, as well as the engineering analyses performed to determine the dynamic response of the inner conductors due to environmental excitations. A bellows is used in both prototype inner conductors in the area near the ceramic RF window, to compensate for thermal expansion and mechanical tolerance build-up. In addition, a bellows is used near the tip of the inner conductor of the alpha prototype for running the power coupler after it is installed on the accelerator. Extensive analytical work has been performed to determine the static loads transmitted by the bellows due to thermally induced expansion on the inner conductor and on the RF window. This paper also discusses this analysis, as well as the mechanical analysis performed to determine the final geometric shape of the bellows. Finally, a discussion of the electromagnetic analysis used to optimize the performance of the power couplers is included.

  4. Mode conversion in hybrid optical fiber coupler

    Science.gov (United States)

    Stasiewicz, Karol A.; Marc, P.; Jaroszewicz, Leszek R.

    2012-04-01

    Designing of all in-line fiber optic systems with a supercontinuum light source gives some issues. The use of a standard single mode fiber (SMF) as an input do not secure single mode transmission in full wavelength range. In the paper, the experimental results of the tested hybrid fiber optic coupler were presented. It was manufactured by fusing a standard single mode fiber (SMF28) and a photonic crystal fiber (PCF). The fabrication process is based on the standard fused biconical taper technique. Two types of large mode area fibers (LMA8 and LAM10 NKT Photonics) with different air holes arrangements were used as the photonic crystal fiber. Spectral characteristics within the range of 800 nm - 1700 nm were presented. All process was optimized to obtain a mode conversion between SMF and PCF and to reach a single mode transmission in the PCF output of the coupler.

  5. Quantitative analysis of coupler tuning

    International Nuclear Information System (INIS)

    Zheng Shuxin; Cui Yupeng; Chen Huaibi; Xiao Liling

    2001-01-01

    The author deduces the equation of coupler frequency deviation Δf and coupling coefficient β instead of only giving the adjusting direction in the process of matching coupler, on the basis of coupling-cavity chain equivalent circuits model. According to this equation, automatic measurement and quantitative display are realized on a measuring system. It contributes to industrialization of traveling-wave accelerators for large container inspection systems

  6. A Third Generation Lower Hybrid Coupler

    International Nuclear Information System (INIS)

    Bernabei, S.; Hosea, J.; Kung, C.; Loesser, D.; Rushinski, J.; Wilson, J.R.; Parker, R.

    2001-01-01

    The Princeton Plasma Physics Laboratory (PPPL) and the Massachusetts Institute of Technology (MIT) are preparing an experiment of current profile control using lower-hybrid waves in order to produce and sustain advanced tokamak regimes in steady-state conditions in Alcator C-Mod. Unlike JET's, ToreSupra's and JT60's couplers, the C-Mod lower-hybrid coupler does not employ the now conventional multijunction design, but will have similar characteristics, compactness, and internal power division while retaining full control of the antenna element phasing. This is achieved by using 3 dB vertical power splitters and a stack of laminated plates with the waveguides milled in them. Construction is simplified and allows easy control and maintenance of all parts. Many precautions are taken to avoid arcing. Special care is also taken to avoid the recycling of reflected power which could affect the coupling and the launched n(subscript ||) spectrum. The results from C-Mod should allow further simplification in the designs of the coupler planned for KSTAR (Korea Superconducting Tokamak Advanced Research) and ITER (International Thermonuclear Experimental Reactor)

  7. Extensiones centrales universales de álgebras Hom-Leibniz

    OpenAIRE

    Pacheco Rego, Natália Maria de Bessa

    2014-01-01

    Las álgebras Hom-Leibniz son espacios vectoriales V dotados de un producto corchete [-,-] : V × V → V y de una aplicación α : V --> V satisfaciendo la denominada identidad Hom-Leibniz: [α (x),[y,z

  8. Wireless power transfer magnetic couplers

    Science.gov (United States)

    Wu, Hunter; Gilchrist, Aaron; Sealy, Kylee

    2016-01-19

    A magnetic coupler is disclosed for wireless power transfer systems. A ferrimagnetic component is capable of guiding a magnetic field. A wire coil is wrapped around at least a portion of the ferrimagnetic component. A screen is capable of blocking leakage magnetic fields. The screen may be positioned to cover at least one side of the ferrimagnetic component and the coil. A distance across the screen may be at least six times an air gap distance between the ferrimagnetic component and a receiving magnetic coupler.

  9. Coupler for nuclear reactor absorber rods

    International Nuclear Information System (INIS)

    Kerz, K.

    1984-01-01

    A coupler is described for absorber rods being suspended during operation of nuclear reactors which includes plurality of actuating elements being movable for individually and jointly releasing the coupler, the movement of each of the actuating elements for releasing the coupler being independently controllable

  10. Broadband polymer microstructured THz fiber coupler with downdoped cores

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Rasmussen, Henrik K.; Bang, Ole

    2010-01-01

    We demonstrate a broadband THz directional coupler based on a dual core photonic crystal fiber (PCF) design with mechanically down-doped core regions. For a center frequency of 1.3 THz we demonstrate a bandwidth of 0.65 THz.......We demonstrate a broadband THz directional coupler based on a dual core photonic crystal fiber (PCF) design with mechanically down-doped core regions. For a center frequency of 1.3 THz we demonstrate a bandwidth of 0.65 THz....

  11. A modified lower hybrid coupler for TPX

    International Nuclear Information System (INIS)

    Bernabei, S.; Greenough, N.

    1995-01-01

    Efforts have concentrated on redesigning the configuration of the Lower Hybrid coupler for TPX tokamak. Several concerns motivated this redesign: reduce the effect of thermal incompatibility between coupler and rf-window material, reduce weight, reduce the risk of wind failure and address the problem of replaceability, increase the reliability by reducing the number connections and finally, reduce the total cost. The result is a highly compact, light and easily serviceable coupler which incorporates some of the simplicity of the multifunction coupler but preserves the spectral flexibility of a conventional coupler

  12. Radford's biproducts and Yetter-Drinfeld modules for monoidal Hom-Hopf algebras

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ling, E-mail: ntliuling@gmail.com [College of Mathematics, Physics and Information Engineering, Zhejiang Normal University, Jinhua 321004 (China); Shen, Bingliang [Shanghai University of Finance and Economics Zhejiang College, Jinhua 321013 (China)

    2014-03-15

    Let (H, α) be a monoidal Hom-bialgebra and (B, β) be a left (H, α)-Hom-module algebra and also a left (H, α)-Hom-comodule coalgebra. Then in this paper, we first introduce the notion of a Hom-smash coproduct, which is a monoidal Hom-coalgebra. Second, we find sufficient and necessary conditions for the Hom-smash product algebra structure and the Hom-smash coproduct coalgebra structure on B ⊗ H to afford B ⊗ H a monoidal Hom-bialgebra structure, generalizing the well-known Radford's biproduct, where the conditions are equivalent to that (B, β) is a bialgebra in the category of Hom-Yetter-Drinfeld modules H/H HYD. Finally, we illustrate the category of Hom-Yetter-Drinfeld modules H/H HYD and prove that the category H/H HYD is a braided monoidal category.

  13. Refractive index engineering of high performance coupler for compact photonic integrated circuits

    Science.gov (United States)

    Liu, Lu; Zhou, Zhiping

    2017-04-01

    High performance couplers are highly desired in many applications, but the design is limited by nearly unchangeable material refractive index. To tackle this issue, refractive index engineering method is investigated, which can be realized by subwavelength grating. Subwavelength gratings are periodical structures with pitches small enough to locally synthesize the refractive index of photonic waveguides, which allows direct control of optical profile as well as easier fabrication process. This review provides an introduction to the basics of subwavelength structures and pay special attention to the design strategies of some representative examples of subwavelength grating devices, including: edge couplers, fiber-chip grating couplers, directional couplers and multimode interference couplers. Benefited from the subwavelength grating which can engineer the refractive index as well as birefringence and dispersion, these devices show better performance when compared to their conventional counterparts.

  14. HOM Dampers or not in Superconducting RF Proton Linacs

    CERN Document Server

    Tückmantel, Joachim

    2009-01-01

    Circular machines are plagued by Coupled Bunch Instabilities, driven by impedance peaks, irrespectively of their frequency relation to machine lines; hence all cavity Higher Order Modes are possible drivers. This is the fundamental reason that all superconducting RF cavities in circular machines are equipped with HOM dampers. This raises the question if HOM damping would not be imperative also in high current proton linacs where a mechanism akin to CBI might exist. To clarify this question we have simulated the longitudinal bunched beam dynamics in linacs, allowing bunch-to-bunch variations in time-of-arrival. Simulations were executed for a generic proton linac with properties close to SNS or the planned SPL at CERN. It was found that for monopole HOMs with high Qext large beam scatter or even beam loss cannot be excluded. Therefore omitting HOM dampers on superconducting RF cavities in high current proton linacs, even pulsed ones, is a very risky decision.

  15. HOM Dampers or not in SUPERCONDUCTING RF Proton Linacs

    CERN Document Server

    Tückmantel, Joachim

    2009-01-01

    Circular machines are plagued by Coupled Bunch Instabilities, driven by impedance peaks, irrespectively of their frequency relation to machine lines; hence all cavity Higher Order Modes are possible drivers. This is the fundamental reason that all superconducting RF cavities in circular machines are equipped with HOM dampers. This raises the question if HOM damping would not be imperative also in high current proton linacs where a mechanism akin to CBI might exist. To clarify this question we have simulated the longitudinal bunched beam dynamics in linacs, allowing bunch-to-bunch variations in time-of-arrival. Simulations were executed for a generic proton linac with properties close to SNS or the planned SPL at CERN. It was found that for monopole HOMs with high Qext large beam scatter or even beam loss cannot be excluded. Therefore omitting HOM dampers on superconducting RF cavities in high current proton linacs, even pulsed ones, is a very risky decision.

  16. Measurement and identification of HOM's in RF cavities

    International Nuclear Information System (INIS)

    Goldberg, D.A.; Rimmer, R.A.

    1997-05-01

    One of the major sources of beam impedance in accelerators is the higher-order modes (HOM's) of the RF cavities. We report here on a number of techniques for the identification of HOM's and measurement of their properties. Central to these techniques is the application of symmetry principles and the effects of symmetry-breaking perturbations (including mode-mixing) to the 'standard' techniques of spectrum measurements and bead pulls

  17. HOM Consideration of 704 MHz and 2.1 GHz Cavities for LEReC Linac

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Binping [RIKEN BNL; Belomestnykh, Sergey [SUNY, Stony Brook; Ben-Zvi, Ilan [RIKEN BNL; Blaskiewicz, Michael [RIKEN BNL; Brennan, Joseph [RIKEN BNL; Brutus, Jean Clifford [RIKEN BNL; Fedotov, Alexei [RIKEN BNL; Hahn, Harald [RIKEN BNL; McIntyre, Gary [RIKEN BNL; Pai, Chien [RIKEN BNL; Smith, Kevin [RIKEN BNL; Tuozzolo, Joseph [RIKEN BNL; Veshcherevich, Vadim [Cornell U., CLASSE; Wu, Qiong [RIKEN BNL; Xin, Tianmu [RIKEN BNL; Xu, Wencan [RIKEN BNL; Zaltsman, Alex [RIKEN BNL

    2016-06-01

    To improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon, the Low Energy RHIC electron Cooler (LEReC) is currently under development at BNL. The Linac of LEReC is designed to deliver 2 MV to 5 MV electron beam, with rms dp/p less than 5·10⁻⁴. The HOM in this Linac is carefully studied to ensure this specification.

  18. A linear atomic quantum coupler

    Energy Technology Data Exchange (ETDEWEB)

    El-Orany, Faisal A A [Department of Mathematics and computer Science, Faculty of Science, Suez Canal University 41522, Ismailia (Egypt); Wahiddin, M R B, E-mail: el_orany@hotmail.co, E-mail: faisal.orany@mimos.m, E-mail: mridza@mimos.m [Cyberspace Security Laboratory, MIMOS Berhad, Technology Park Malaysia, 57000 Kuala Lumpur (Malaysia)

    2010-04-28

    In this paper we develop the notion of the linear atomic quantum coupler. This device consists of two modes propagating into two waveguides, each of which includes a localized atom. These waveguides are placed close enough to allow exchange of energy between them via evanescent waves. Each mode interacts with the atom in the same waveguide in the standard way as the Jaynes-Cummings model (JCM) and with the atom-mode system in the second waveguide via the evanescent wave. We present the Hamiltonian for this system and deduce its wavefunction. We investigate the atomic inversions and the second-order correlation function. In contrast to the conventional coupler the atomic quantum coupler is able to generate nonclassical effects. The atomic inversions can exhibit a long revival-collapse phenomenon as well as subsidiary revivals based on the competition among the switching mechanisms in the system. Finally, under certain conditions the system can yield the results of the two-mode JCM.

  19. Silica-on-silicon optical couplers and coupler based optical filters

    DEFF Research Database (Denmark)

    Leick, Lasse

    2002-01-01

    is not an adequate description of the waveguides. A simple application for an optical couplers is as a 980/1550 nm mulitmplexer for erbium doped wavguide amplifiers. A numerical analysis shows that a directional coupler has acceptable specifications, whereas a mulit mode interference coupler does not. The wavelength......This work concerns modeling and chracterization of non ampligying silica-on-silicon optical components for wavelength division mulitplexed networks. Emphasis is placed on optical couplers and how they can be used as building blocks for devices with a larger complexity. It has been investigated how...... to construct wavelength flattened and process tolerant couplers. A thorough comparison between directional couplers, multi mode interference couplers and interferometer-based couplers has been performed. Numerically all these architectures have the ability to obtain similar wavelength-flatness, but the multi...

  20. Development of fundamental power coupler for C-ADS superconducting elliptical cavities

    Science.gov (United States)

    Gu, Kui-Xiang; Bing, Feng; Pan, Wei-Min; Huang, Tong-Ming; Ma, Qiang; Meng, Fan-Bo

    2017-06-01

    5-cell elliptical cavities have been selected for the main linac of the China Accelerator Driven sub-critical System (C-ADS) in the medium energy section. According to the design, each cavity should be driven with radio frequency (RF) energy up to 150 kW by a fundamental power coupler (FPC). As the cavities work with high quality factor and high accelerating gradient, the coupler should keep the cavity from contamination in the assembly procedure. To fulfil the requirements, a single-window coaxial type coupler was designed with the capabilities of handling high RF power, class 10 clean room assembly, and heat load control. This paper presents the coupler design and gives details of RF design, heat load optimization and thermal analysis as well as multipacting simulations. In addition, a primary high power test has been performed and is described in this paper. Supported by China ADS Project (XDA03020000) and National Natural Science Foundation of China (11475203)

  1. Fiber-chip edge coupler with large mode size for silicon photonic wire waveguides.

    Science.gov (United States)

    Papes, Martin; Cheben, Pavel; Benedikovic, Daniel; Schmid, Jens H; Pond, James; Halir, Robert; Ortega-Moñux, Alejandro; Wangüemert-Pérez, Gonzalo; Ye, Winnie N; Xu, Dan-Xia; Janz, Siegfried; Dado, Milan; Vašinek, Vladimír

    2016-03-07

    Fiber-chip edge couplers are extensively used in integrated optics for coupling of light between planar waveguide circuits and optical fibers. In this work, we report on a new fiber-chip edge coupler concept with large mode size for silicon photonic wire waveguides. The coupler allows direct coupling with conventional cleaved optical fibers with large mode size while circumventing the need for lensed fibers. The coupler is designed for 220 nm silicon-on-insulator (SOI) platform. It exhibits an overall coupling efficiency exceeding 90%, as independently confirmed by 3D Finite-Difference Time-Domain (FDTD) and fully vectorial 3D Eigenmode Expansion (EME) calculations. We present two specific coupler designs, namely for a high numerical aperture single mode optical fiber with 6 µm mode field diameter (MFD) and a standard SMF-28 fiber with 10.4 µm MFD. An important advantage of our coupler concept is the ability to expand the mode at the chip edge without leading to high substrate leakage losses through buried oxide (BOX), which in our design is set to 3 µm. This remarkable feature is achieved by implementing in the SiO 2 upper cladding thin high-index Si 3 N 4 layers. The Si 3 N 4 layers increase the effective refractive index of the upper cladding near the facet. The index is controlled along the taper by subwavelength refractive index engineering to facilitate adiabatic mode transformation to the silicon wire waveguide while the Si-wire waveguide is inversely tapered along the coupler. The mode overlap optimization at the chip facet is carried out with a full vectorial mode solver. The mode transformation along the coupler is studied using 3D-FDTD simulations and with fully-vectorial 3D-EME calculations. The couplers are optimized for operating with transverse electric (TE) polarization and the operating wavelength is centered at 1.55 µm.

  2. Cancellation of RF Coupler-Induced Emittance Due to Astigmatism

    Energy Technology Data Exchange (ETDEWEB)

    Dowell, David H.; /SLAC

    2016-12-11

    It is well-known that the electron beam quality required for applications such as FEL’s and ultra-fast electron diffraction can be degraded by the asymmetric fields introduced by the RF couplers of superconducting linacs. This effect is especially troublesome in the injector where the low energy beam from the gun is captured into the first high gradient accelerator section. Unfortunately modifying the established cavity design is expensive and time consuming, especially considering that only one or two sections are needed for an injector. Instead, it is important to analyze the coupler fields to understand their characteristics and help find less costly solutions for their cancellation and mitigation. This paper finds the RF coupler-induced emittance for short bunches is mostly due to the transverse spatial sloping or tilt of the field, rather than the field’s time-dependence. It is shown that the distorting effects of the coupler can be canceled with a static (DC) quadrupole lens rotated about the z-axis.

  3. A Novel Multimode Waveguide Coupler for Accurate Power Measurement of Traveling Wave Tube Harmonic Frequencies

    Science.gov (United States)

    Wintucky, Edwin G.; Simons, Rainee N.

    2014-01-01

    This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler fabricated from two dissimilar waveguides is capable of isolating the power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT). In addition to accurate power measurements at harmonic frequencies, a potential application of the MDC is in the design of a beacon source for atmospheric propagation studies at millimeter-wave frequencies.

  4. HOM Survey of the First CEBAF Upgrade Style Cavity Pair

    International Nuclear Information System (INIS)

    Marhauser, Frank; Daly, Edward; Davis, G.; Drury, Michael; Grenoble, Christiana; Hogan, John; Manus, Robert; Preble, Joseph; Reece, Charles; Rimmer, Robert; Tian, Kai; Wang, Haipeng

    2009-01-01

    The planned upgrade of the Continuous Electron Beam Accelerator Facility (CEBAF) at the Thomas Jefferson National Accelerator Laboratory (JLab) requires ten new superconducting rf (SRF) cavity cryomodules to double the beam energy to the envisaged 12 GeV. Adequate cavity Higher Order Mode (HOM) suppression is essential to avoid multipass, multibunch beam break-up (BBU) instabilities of the recirculating beam. We report on detailed HOM surveys performed for the first two upgrade style cavities tested in a dedicated cavity pair cryomodule at 2K. The safety margin to the BBU threshold budget at 12 GeV has been assessed.

  5. Surface acoustic waves voltage controlled directional coupler

    Science.gov (United States)

    Golan, G.; Griffel, G.; Yanilov, E.; Ruschin, S.; Seidman, A.; Croitoru, N.

    1988-10-01

    An important condition for the development of surface wave integrated-acoustic devices is the ability to guide and control the propagation of the acoustic energy. This can be implemented by deposition of metallic "loading" channels on an anisotropic piezoelectric substrate. Deposition of such two parallel channels causes an effective coupling of acoustic energy from one channel to the other. A basic requirement for this coupling effect is the existence of the two basic modes: a symmetrical and a nonsymmetrical one. A mode map that shows the number of sustained modes as a function of the device parameters (i.e., channel width; distance between channels; material velocity; and acoustical exciting frequency) is presented. This kind of map can help significantly in the design process of such a device. In this paper we devise an advanced acoustical "Y" coupler with the ability to control its effective coupling by an externally applied voltage, thereby causing modulation of the output intensities of the signals.

  6. Analysis of the rectangular resonator with butterfly MMI coupler using SOI

    Science.gov (United States)

    Kim, Sun-Ho; Park, Jun-Hee; Kim, Eudum; Jeon, Su-Jin; Kim, Ji-Hoon; Choi, Young-Wan

    2018-02-01

    We propose a rectangular resonator sensor structure with butterfly MMI coupler using SOI. It consists of the rectangular resonator, total internal reflection (TIR) mirror, and the butterfly MMI coupler. The rectangular resonator is expected to be used as bio and chemical sensors because of the advantages of using MMI coupler and the absence of bending loss unlike ring resonators. The butterfly MMI coupler can miniaturize the device compared to conventional MMI by using a linear butterfly shape instead of a square in the MMI part. The width, height, and slab height of the rib type waveguide are designed to be 1.5 μm, 1.5 μm, and 0.9 μm, respectively. This structure is designed as a single mode. When designing a TIR mirror, we considered the Goos-Hänchen shift and critical angle. We designed 3:1 MMI coupler because rectangular resonator has no bending loss. The width of MMI is designed to be 4.5 μm and we optimize the length of the butterfly MMI coupler using finite-difference time-domain (FDTD) method for higher Q-factor. It has the equal performance with conventional MMI even though the length is reduced by 1/3. As a result of the simulation, Qfactor of rectangular resonator can be obtained as 7381.

  7. Summary of the workshop on HOM in SPL, held at CERN June 25-26.

    CERN Document Server

    Lombardi, A; Weingarten, W

    2009-01-01

    A mini-workshop on the subject of HOMs in a superconducting proton linac was held at CERN on the 25th and 26th June 2009. The purpose of this workshop was to discuss more specifically the effects of HOMs on beam dynamics in the SPL and comparable accelerators and to provide guidelines for the specification of HOM dampers, if necessary.

  8. Large-Area Binary Blazed Grating Coupler between Nanophotonic Waveguide and LED

    Directory of Open Access Journals (Sweden)

    Hongqiang Li

    2014-01-01

    Full Text Available A large-area binary blazed grating coupler for the arrayed waveguide grating (AWG demodulation integrated microsystem on silicon-on-insulator (SOI was designed for the first time. Through the coupler, light can be coupled into the SOI waveguide from the InP-based C-band LED for the AWG demodulation integrated microsystem to function. Both the length and width of the grating coupler are 360 μm, as large as the InP-based C-band LED light emitting area in the system. The coupler was designed and optimized based on the finite difference time domain method. When the incident angle of the light source is 0°, the coupling efficiency of the binary blazed grating is 40.92%, and the 3 dB bandwidth is 72 nm at a wavelength of 1550 nm.

  9. Relative Hom-Hopf modules and total integrals

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Shuangjian [School of Mathematics and Statistics, Guizhou University of Finance and Economics, Guiyang 550025 (China); Zhang, Xiaohui [Department of Mathematics, Southeast University, Nanjing 210096 (China); Wang, Shengxiang, E-mail: wangsx-math@163.com [School of Mathematics and Finance, Chuzhou University, Chuzhou 239000 (China); Department of Mathematics, Nanjing University, Nanjing 210093 (China)

    2015-02-15

    Let (H, α) be a monoidal Hom-Hopf algebra and (A, β) a right (H, α)-Hom-comodule algebra. We first investigate the criterion for the existence of a total integral of (A, β) in the setting of monoidal Hom-Hopf algebras. Also, we prove that there exists a total integral ϕ : (H, α) → (A, β) if and only if any representation of the pair (H, A) is injective in a functorial way, as a corepresentation of (H, α), which generalizes Doi’s result. Finally, we define a total quantum integral γ : H → Hom(H, A) and prove the following affineness criterion: if there exists a total quantum integral γ and the canonical map ψ : A⊗{sub B}A → A ⊗ H, a⊗{sub B}b ↦ β{sup −1}(a) b{sub [0]} ⊗ α(b{sub [1]}) is surjective, then the induction functor A⊗{sub B}−:ℋ{sup ~}(ℳ{sub k}){sub B}→ℋ{sup ~}(ℳ{sub k}){sub A}{sup H} is an equivalence of categories.

  10. Relative Hom-Hopf modules and total integrals

    International Nuclear Information System (INIS)

    Guo, Shuangjian; Zhang, Xiaohui; Wang, Shengxiang

    2015-01-01

    Let (H, α) be a monoidal Hom-Hopf algebra and (A, β) a right (H, α)-Hom-comodule algebra. We first investigate the criterion for the existence of a total integral of (A, β) in the setting of monoidal Hom-Hopf algebras. Also, we prove that there exists a total integral ϕ : (H, α) → (A, β) if and only if any representation of the pair (H, A) is injective in a functorial way, as a corepresentation of (H, α), which generalizes Doi’s result. Finally, we define a total quantum integral γ : H → Hom(H, A) and prove the following affineness criterion: if there exists a total quantum integral γ and the canonical map ψ : A⊗ B A → A ⊗ H, a⊗ B b ↦ β −1 (a) b [0] ⊗ α(b [1] ) is surjective, then the induction functor A⊗ B −:ℋ ~ (ℳ k ) B →ℋ ~ (ℳ k ) A H is an equivalence of categories

  11. Miniature mechanical transfer optical coupler

    Science.gov (United States)

    Abel, Philip [Overland Park, KS; Watterson, Carl [Kansas City, MO

    2011-02-15

    A miniature mechanical transfer (MT) optical coupler ("MMTOC") for optically connecting a first plurality of optical fibers with at least one other plurality of optical fibers. The MMTOC may comprise a beam splitting element, a plurality of collimating lenses, and a plurality of alignment elements. The MMTOC may optically couple a first plurality of fibers disposed in a plurality of ferrules of a first MT connector with a second plurality of fibers disposed in a plurality of ferrules of a second MT connector and a third plurality of fibers disposed in a plurality of ferrules of a third MT connector. The beam splitting element may allow a portion of each beam of light from the first plurality of fibers to pass through to the second plurality of fibers and simultaneously reflect another portion of each beam of light from the first plurality of fibers to the third plurality of fibers.

  12. UV written compact broadband optical couplers

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    In this paper the first demonstration of compact asymmetric directional couplers made by UV writing is presented. The combined performance in terms bandwidth, loss and compactness exceeds that reported using other, more elaborate fabrication techniques.......In this paper the first demonstration of compact asymmetric directional couplers made by UV writing is presented. The combined performance in terms bandwidth, loss and compactness exceeds that reported using other, more elaborate fabrication techniques....

  13. Candida albicans Hom6 is a homoserine dehydrogenase involved in protein synthesis and cell adhesion

    Directory of Open Access Journals (Sweden)

    Pei-Wen Tsai

    2017-12-01

    Full Text Available Background/Purpose: Candida albicans is a common fungal pathogen in humans. In healthy individuals, C. albicans represents a harmless commensal organism, but infections can be life threatening in immunocompromised patients. The complete genome sequence of C. albicans is extremely useful for identifying genes that may be potential drug targets and important for pathogenic virulence. However, there are still many uncharacterized genes in the Candida genome database. In this study, we investigated C. albicans Hom6, the functions of which remain undetermined experimentally. Methods: HOM6-deleted and HOM6-reintegrated mutant strains were constructed. The mutant strains were compared with wild-type in their growth in various media and enzyme activity. Effects of HOM6 deletion on translation were further investigated by cell susceptibility to hygromycin B or cycloheximide, as well as by polysome profiling, and cell adhesion to polystyrene was also determined. Results: C. albicans Hom6 exhibits homoserine dehydrogenase activity and is involved in the biosynthesis of methionine and threonine. HOM6 deletion caused translational arrest in cells grown under amino acid starvation conditions. Additionally, Hom6 protein was found in both cytosolic and cell-wall fractions of cultured cells. Furthermore, HOM6 deletion reduced C. albicans cell adhesion to polystyrene, which is a common plastic used in many medical devices. Conclusion: Given that there is no Hom6 homologue in mammalian cells, our results provided an important foundation for future development of new antifungal drugs. Keywords: Candida albicans, cell adhesion, Hom6, homoserine dehydrogenase, protein synthesis

  14. Studying and measuring the gamma radiation doses in Homs city

    International Nuclear Information System (INIS)

    Sofaan, A. H.

    2001-01-01

    The gamma radiation dose was measured in Homs city by using many portable dosimeters (electronic dosimeter and Geiger-Muller). The measurements were carried out in the indoor and outdoor buildings, for different time period, through one year (1999-2000). High purity germanium detector with low back ground radiation (HpGe) was used to determine radiation element contained in some building and the surrounding soil. The statistical analysis laws were applied to make sure that the measured dose distribution around average value is normal distribution. The measurement indicates that the gamma indoor dose varies from 312μSv/y to 511μSv/y, with the average annual dose of 385μSv/y. However the gamma outdoor dose rate varies from 307μSv/y to 366μSv/y with an average annual dose 385μSv/y. The annual outdoor gamma radiation dose is about %16 lower than the outdoor dose in Homs City. These measurements have indicated that environmental gamma doses in Homs City are relatively low. This is because that most of the soils and rocks in the area are limestone. (author)

  15. Ternary q-Virasoro-Witt Hom-Nambu-Lie algebras

    International Nuclear Information System (INIS)

    Ammar, F; Makhlouf, A; Silvestrov, S

    2010-01-01

    In this paper we construct ternary q-Virasoro-Witt algebras which q-deform the ternary Virasoro-Witt algebras constructed by Curtright, Fairlie and Zachos using su(1, 1) enveloping algebra techniques. The ternary Virasoro-Witt algebras constructed by Curtright, Fairlie and Zachos depend on a parameter and are not Nambu-Lie algebras for all but finitely many values of this parameter. For the parameter values for which the ternary Virasoro-Witt algebras are Nambu-Lie, the corresponding ternary q-Virasoro-Witt algebras constructed in this paper are also Hom-Nambu-Lie because they are obtained from the ternary Nambu-Lie algebras using the composition method. For other parameter values this composition method does not yield a Hom-Nambu-Lie algebra structure for q-Virasoro-Witt algebras. We show however, using a different construction, that the ternary Virasoro-Witt algebras of Curtright, Fairlie and Zachos, as well as the general ternary q-Virasoro-Witt algebras we construct, carry a structure of the ternary Hom-Nambu-Lie algebra for all values of the involved parameters.

  16. A coupler for parasitic mode diagnosis in an X-band triaxial klystron amplifier

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2017-10-01

    Full Text Available The traditional methods of parasitic mode excitation diagnosis in an X-band triaxial klystron amplifier (TKA meet two difficulties: limited installation space and vacuum sealing. In order to solve these issues, a simple and compact coupler with good sealing performance, which can prevent air flow between the main and the auxiliary waveguides, is proposed and investigated experimentally. The coupler is designed with the aperture diffraction theory and the finite-different time-domain (FDTD method. The designed coupler consists of a main coaxial waveguide (for microwave transmission and a rectangular auxiliary waveguide (for parasitic mode diagnosis. The entire coupler structure has been fabricated by macromolecule polymer which is transparent to microwave signal in frequency range of X-band. The metal coating of about 200 microns has been performed through electroplating technique to ensure that the device operates well at high power. A small aperture is made in the metal coating. Hence, microwave can couple through the hole and the wave-transparent medium, whereas air flow is blocked by the wave-transparent medium. The coupling coefficient is analyzed and simulated with CST software. The coupler model is also included in particle-in-cell (PIC simulation with CHIPIC software and the associated parasitic mode excitation is studied. A frequency component of 11.46 GHz is observed in the FFT of the electric field of the drift tube and its corresponding competition mode appears as TE61 mode according to the electric field distribution. Besides, a frequency component of 10.8 GHz is also observed in the FFT of the electric field. After optimization of TE61 mode suppression, an experiment of the TKA with the designed coupler is carried out and the parasitic mode excitation at 10.8 GHz is observed through the designed coupler.

  17. Geometric optimisation of an accurate cosine correcting optic fibre coupler for solar spectral measurement

    Science.gov (United States)

    Cahuantzi, Roberto; Buckley, Alastair

    2017-09-01

    Making accurate and reliable measurements of solar irradiance is important for understanding performance in the photovoltaic energy sector. In this paper, we present design details and performance of a number of fibre optic couplers for use in irradiance measurement systems employing remote light sensors applicable for either spectrally resolved or broadband measurement. The angular and spectral characteristics of different coupler designs are characterised and compared with existing state-of-the-art commercial technology. The new coupler designs are fabricated from polytetrafluorethylene (PTFE) rods and operate through forward scattering of incident sunlight on the front surfaces of the structure into an optic fibre located in a cavity to the rear of the structure. The PTFE couplers exhibit up to 4.8% variation in scattered transmission intensity between 425 nm and 700 nm and show minimal specular reflection, making the designs accurate and reliable over the visible region. Through careful geometric optimization near perfect cosine dependence on the angular response of the coupler can be achieved. The PTFE designs represent a significant improvement over the state of the art with less than 0.01% error compared with ideal cosine response for angles of incidence up to 50°.

  18. Geometric optimisation of an accurate cosine correcting optic fibre coupler for solar spectral measurement.

    Science.gov (United States)

    Cahuantzi, Roberto; Buckley, Alastair

    2017-09-01

    Making accurate and reliable measurements of solar irradiance is important for understanding performance in the photovoltaic energy sector. In this paper, we present design details and performance of a number of fibre optic couplers for use in irradiance measurement systems employing remote light sensors applicable for either spectrally resolved or broadband measurement. The angular and spectral characteristics of different coupler designs are characterised and compared with existing state-of-the-art commercial technology. The new coupler designs are fabricated from polytetrafluorethylene (PTFE) rods and operate through forward scattering of incident sunlight on the front surfaces of the structure into an optic fibre located in a cavity to the rear of the structure. The PTFE couplers exhibit up to 4.8% variation in scattered transmission intensity between 425 nm and 700 nm and show minimal specular reflection, making the designs accurate and reliable over the visible region. Through careful geometric optimization near perfect cosine dependence on the angular response of the coupler can be achieved. The PTFE designs represent a significant improvement over the state of the art with less than 0.01% error compared with ideal cosine response for angles of incidence up to 50°.

  19. Design of an rf quadrupole for Landau damping

    Directory of Open Access Journals (Sweden)

    K. Papke

    2017-08-01

    Full Text Available The recently proposed superconducting quadrupole resonator for Landau damping in accelerators is subjected to a detailed design study. The optimization process of two different cavity types is presented following the requirements of the High Luminosity Large Hadron Collider (HL-LHC with the main focus on quadrupolar strength, surface peak fields, and impedance. The lower order and higher order mode (LOM and HOM spectrum of the optimized cavities is investigated and different approaches for their damping are proposed. On the basis of an example the first two higher order multipole errors are calculated. Likewise on this example the required rf power and optimal external quality factor for the input coupler is derived.

  20. Broadband Silicon-On-Insulator directional couplers using a combination of straight and curved waveguide sections.

    Science.gov (United States)

    Chen, George F R; Ong, Jun Rong; Ang, Thomas Y L; Lim, Soon Thor; Png, Ching Eng; Tan, Dawn T H

    2017-08-03

    Broadband Silicon-On-Insulator (SOI) directional couplers are designed based on a combination of curved and straight coupled waveguide sections. A design methodology based on the transfer matrix method (TMM) is used to determine the required coupler section lengths, radii, and waveguide cross-sections. A 50/50 power splitter with a measured bandwidth of 88 nm is designed and fabricated, with a device footprint of 20 μm × 3 μm. In addition, a balanced Mach-Zehnder interferometer is fabricated showing an extinction ratio of >16 dB over 100 nm of bandwidth.

  1. Fully etched apodized grating coupler on the SOI platform with −058 dB coupling efficiency

    DEFF Research Database (Denmark)

    Ding, Yunhong; Peucheret, Christophe; Ou, Haiyan

    2014-01-01

    We design and fabricate an ultrahigh coupling efficiency (CE) fully etched apodized grating coupler on the silicon- on-insulator (SOI) platform using subwavelength photonic crystals and bonded aluminum mirror. Fabrication error sensitivity andcoupling angle dependence are experimentally investiga......We design and fabricate an ultrahigh coupling efficiency (CE) fully etched apodized grating coupler on the silicon- on-insulator (SOI) platform using subwavelength photonic crystals and bonded aluminum mirror. Fabrication error sensitivity andcoupling angle dependence are experimentally...

  2. Natural radiation level in drinking water in Homs city

    International Nuclear Information System (INIS)

    Shweikani, R.; Raja, Gh.

    2008-11-01

    In this study, radon concentrations were measured at the sources of drinking water and in some tap water in houses in Homs County. All measurements showed that concentrations are within the international allowed limits and there is no big difference in concentration between the sources and the houses. Also total alpha/beta and radium-226 content were measured in the samples of the sources and the houses using liquid scintillation counter. All measurements showed that concentrations are within the international allowed limits. (authors)

  3. Ultra-low coupling loss fully-etched apodized grating coupler with bonded metal mirror

    DEFF Research Database (Denmark)

    Ding, Yunhong; Peucheret, Christophe; Ou, Haiyan

    2014-01-01

    A fully etched apodized grating coupler with bonded metal mirror is designed and demonstrated on the silicon-on-insulator platform, showing an ultra-low coupling loss of only 1.25 dB with 3 dB bandwidth of 69 nm.......A fully etched apodized grating coupler with bonded metal mirror is designed and demonstrated on the silicon-on-insulator platform, showing an ultra-low coupling loss of only 1.25 dB with 3 dB bandwidth of 69 nm....

  4. Ultrahigh-efficiency apodized grating coupler using fully etched photonic crystals

    DEFF Research Database (Denmark)

    Ding, Yunhong; Ou, Haiyan; Peucheret, Christophe

    2013-01-01

    We present an efficient method to design apodized grating couplers with Gaussian output profiles for efficient coupling between standard single mode fibers and silicon chips. An apodized grating coupler using fully etched photonic crystal holes on the silicon-on-insulator platform is designed......, and fabricated in a single step of lithography and etching. An ultralow coupling loss of x2212;1.74x2009;x2009;dB (67% coupling efficiency) with a 3xA0;dB bandwidth of 60xA0;nm is experimentally measured....

  5. Microfabrication of pre-aligned fiber bundle couplers using ultraviolet lithography of SU-8

    OpenAIRE

    Yang, Ren; Soper, Steven A.; Wang, Wanjun

    2006-01-01

    This paper describes the design, microfabrication and testing of a pre-aligned array of fiber couplers using direct UV-lithography of SU-8. The fiber coupler array includes an out-of-plane refractive microlens array and two fiberport collimator arrays. With the optical axis of the pixels parallel to the substrate, each pixel of the microlens array can be pre-aligned with the corresponding pixels of the fiberport collimator array as defined by the lithography mask design. This out-of-plane pol...

  6. High efficiency diffractive grating coupler based on transferred silicon nanomembrane overlay on photonic waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Tapas Kumar; Zhou Weidong [University of Texas at Arlington, Department of Electrical Engineering, NanoFAB Center, Arlington, TX 76019-0072 (United States)

    2009-04-21

    We report here the design of a new type of high efficiency grating coupler, based on single crystalline Si nanomembrane overlay and stacking. Such high efficiency diffractive grating couplers are designed for the purpose of coupling light between single mode fibres and nanophotonic waveguides, and for the coupling between multiple photonic interconnect layers for compact three-dimensional vertical integration. Two-dimensional model simulation based on eigenmode expansion shows a diffractive power-up efficiency of 81% and a fibre coupling efficiency of 64%. With nanomembrane stacking, it is feasible to integrate the side-distributed Bragg reflector and bottom reflector, which can lead to the diffractive power-up efficiency and the fibre coupling efficiency of 97% and 73.5%, respectively. For a negatively detuned coupler, the bottom reflector is not needed, and the diffractive power-up efficiency can reach 98% over a large spectral range. The device is extremely tolerant to fabrication errors.

  7. Multiplexing of adjacent vortex modes with the forked grating coupler

    Science.gov (United States)

    Nadovich, Christopher T.; Kosciolek, Derek J.; Crouse, David T.; Jemison, William D.

    2017-08-01

    For vortex fiber multiplexing to reach practical commercial viability, simple silicon photonic interfaces with vortex fiber will be required. These interfaces must support multiplexing. Toward this goal, an efficient singlefed multimode Forked Grating Coupler (FGC) for coupling two different optical vortex OAM charges to or from the TE0 and TE1 rectangular waveguide modes has been developed. A simple, apodized device implemented with e-beam lithography and a conventional dual-etch processing on SOI wafer exhibits low crosstalk and reasonable mode match. Advanced designs using this concept are expected to further improve performance.

  8. Near-field probing of photonic crystal directional couplers

    DEFF Research Database (Denmark)

    Volkov, V. S.; Bozhevolnyi, S. I.; Borel, Peter Ingo

    2006-01-01

    We report the design, fabrication and characterization of a photonic crystal directional with a size of ~20 x 20 mm2 fabricated in silicon-on-insulator material. Using a scanning near-field optical microscope we demonstrate a high coupling efficiency for TM polarized light at telecom wavelengths....... By comparing the near-field optical images recorded in and after the directional coupler area, the features of light distribution are analyzed. Finally, the scanning near-field optical microscope observations are found to be in agreement with the transmission measurements conducted with the same sample....

  9. Time-Domain Simulation of RF Couplers

    International Nuclear Information System (INIS)

    Smithe, David; Carlsson, Johan; Austin, Travis

    2009-01-01

    We have developed a finite-difference time-domain (FDTD) fluid-like approach to integrated plasma-and-coupler simulation [1], and show how it can be used to model LH and ICRF couplers in the MST and larger tokamaks.[2] This approach permits very accurate 3-D representation of coupler geometry, and easily includes non-axi-symmetry in vessel wall, magnetic equilibrium, and plasma density. The plasma is integrated with the FDTD Maxwell solver in an implicit solve that steps over electron time-scales, and permits tenuous plasma in the coupler itself, without any need to distinguish or interface between different regions of vacuum and/or plasma. The FDTD algorithm is also generalized to incorporate a time-domain sheath potential [3] on metal structures within the simulation, to look for situations where the sheath potential might generate local sputtering opportunities. Benchmarking of the time-domain sheath algorithm has been reported in the references. Finally, the time-domain software [4] permits the use of particles, either as field diagnostic (test particles) or to self-consistently compute plasma current from the applied RF power.

  10. HOM power propagation and attenuation in PEP-II B-factory

    International Nuclear Information System (INIS)

    Lin, X.E.; Ng, C.K.; Ko, K.

    1997-09-01

    Most of the higher-order-mode (HOM) power that propagates in the PEP-II rings is generated i the RF cavities but its content in terms of TE and TM components has not been accurately determined. For purpose of shielding beamline components such as bellows and BPMs from TE power penetration and determining the heating on the cavity HOM absorber, this HOM power content and its distribution profile around the rings are needed. This paper calculates the TE and TM contributions of the RF cavities to the circulating HOM power and their transmission properties at another cavity downstream. By considering both the generation in, and scattering by the cavities, as well as the attenuation along the vacuum chamber, a complete distribution profile for the TE and TM HOM power can be obtained

  11. RF characterization and testing of ridge waveguide transitions for RF power couplers

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rajesh; Jose, Mentes; Singh, G.N. [Ion Accelerator Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Girish [Department of Electrical Engineering, IIT Bombay, Mumbai 400076,India (India); Bhagwat, P.V. [Ion Accelerator Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2016-12-01

    RF characterization of rectangular to ridge waveguide transitions for RF power couplers has been carried out by connecting them back to back. Rectangular waveguide to N type adapters are first calibrated by TRL method and then used for RF measurements. Detailed information is obtained about their RF behavior by measurements and full wave simulations. It is shown that the two transitions can be characterized and tuned for required return loss at design frequency of 352.2 MHz. This opens the possibility of testing and conditioning two transitions together on a test bench. Finally, a RF coupler based on these transitions is coupled to an accelerator cavity. The power coupler is successfully tested up to 200 kW, 352.2 MHz with 0.2% duty cycle.

  12. Topology optimization of grating couplers for the efficient excitation of surface plasmons

    DEFF Research Database (Denmark)

    Andkjær, Jacob Anders; Sigmund, Ole; Nishiwaki, Shinji

    2010-01-01

    We propose a methodology for a systematic design of grating couplers for efficient excitation of surface plasmons at metal-dielectric interfaces. The methodology is based on a two-dimensional topology optimization formulation based on the H-polarized scalar Helmholtz equation and finite-element m...

  13. Structural Analysis of Taper-Threaded Rebar Couplers

    International Nuclear Information System (INIS)

    Chu, Seok Jae; Kwon, Hyuk Mo; Seo, Sang Hwan

    2014-01-01

    A number of rebar couplers were developed by the leading companies. The information about the products is available from the company website. However, the theory on the taper-threaded coupler is not available. In this paper, the mechanics of the taper-thread was developed to understand the effect of the tightening torque. Structural analysis of our own newly developed rebar coupler was done to improve the strength of the coupler. The taper-threaded rebar coupler was analyzed. The tightening of the rebar into the coupler developed a circumferential stress in the coupler. The circumferential stress depends on the coefficient of friction as well as the tightening torque. The circumferential stress is less than the allowable stress 20 kgf/mm 2 of the material for the coefficient of friction greater than 0.1. The tightening of the rebar into the coupler and the subsequent tensioning was simulated using CATIA. Linear elastic analysis considering contact was done. The tightening of the taper-threaded rebar developed a uniform stress distribution in both standard coupler and position coupler. On the other hand, the tightening of the nut in the axial direction developed a non-uniform stress distribution. Similarly the tensioning also developed a non-uniform stress distribution

  14. Free electron laser variable bridge coupler

    International Nuclear Information System (INIS)

    Spalek, G.; Billen, J.H.; Garcia, J.A.; McMurry, D.E.; Harnsborough, L.D.; Giles, P.M.; Stevens, S.B.

    1985-01-01

    The Los Alamos free-electron laser (FEL) is being modified to test a scheme for recovering most of the power in the residual 20-MeV electron beam by decelerating the microbunches in a linear standing-wave accelerator and using the recovered energy to accelerate new beam. A variable-coupler low-power model that resonantly couples the accelerator and decelerator structures has been built and tested. By mixing the TE 101 and TE 102 modes, this device permits continuous variation of the decelerator fields relative to the accelerator fields through a range of 1:1 to 1:2.5. Phase differences between the two structures are kept below 1 0 and are independent of power-flow direction. The rf power is also fed to the two structures through this coupling device. Measurements were also made on a three-post-loaded variable coupler that is a promising candidate for the same task

  15. Required cavity HOM deQing calculated from probability estimates of coupled bunch instabilities in the APS ring

    International Nuclear Information System (INIS)

    Emery, L.

    1993-01-01

    A method of determining the deQing requirement of individual cavity higher-order modes (HOM) for a multi-cavity RF system is presented and applied to the APS ring. Since HOM resonator frequency values are to some degree uncertain, the HOM frequencies should be regarded as random variables in predicting the stability of the coupled bunch beam modes. A Monte Carlo simulation provides a histogram of the growth rates from which one obtains an estimate of the probability of instability. The damping of each HOM type is determined such that the damping effort is economized, i.e. no single HOM dominates the specified growth rate histogram

  16. All silicon waveguide spherical microcavity coupler device.

    Science.gov (United States)

    Xifré-Pérez, E; Domenech, J D; Fenollosa, R; Muñoz, P; Capmany, J; Meseguer, F

    2011-02-14

    A coupler based on silicon spherical microcavities coupled to silicon waveguides for telecom wavelengths is presented. The light scattered by the microcavity is detected and analyzed as a function of the wavelength. The transmittance signal through the waveguide is strongly attenuated (up to 25 dB) at wavelengths corresponding to the Mie resonances of the microcavity. The coupling between the microcavity and the waveguide is experimentally demonstrated and theoretically modeled with the help of FDTD calculations.

  17. CAMAC/PDP 11-45 coupler

    International Nuclear Information System (INIS)

    Pascual, Joseph; Raoul, J.-C.

    1978-04-01

    The complex experimental devices used in high energy physics require the use of minicomputers. The latter are coupled to the detectors using the CAMAC standard which has been adopted by the majority of high energy physics laboratories, much to the ease of international collaboration. The performance of industrially available interfaces having shown to be inadequate, the DPhPE has undertaken the development of a multibranche CAMAC/PDP 11-45 coupler. This system can control up to 49 crates shared out between 7 branches. It consists of a programmed channel and up to three high speed (556 Kwords/second) automatic channels. The four channels can work simultaneously through time sharing. The coupler includes a LAM handling system. The correspondent software has been developed simultaneously: the monitor is an extended version of the RT 11 system supplied by the manufacturer. This interface has been used so far in five experiments on the CERN PS and SPS. Besides this publication, intended to give a description of the coupler, a user's utilisation manuel exists in English [fr

  18. RF Processing of the Couplers for the SNS Superconducting Cavities

    International Nuclear Information System (INIS)

    Y.Kang; I.E. Campisi; D. Stout; A. Vassioutchenko; M. Stirbet; M. Drury; T. Powers

    2005-01-01

    All eighty-one fundamental power couplers for the 805 MHz superconducting cavities of the SNS linac have been RF conditioned and installed in the cryomodules successfully. The couplers were RF processed at JLAB or at the SNS in ORNL: more than forty couplers have been RF conditioned in the SNS RF Test Facility (RFTF) after the first forty couplers were conditioned at JLAB. The couplers were conditioned up to 650 kW forward power at 8% duty cycle in traveling and standing waves. They were installed on the cavities in the cryomodules and then assembled with the airside waveguide transitions. The couplers have been high power RF tested with satisfactory accelerating field gradients in the cooled cavities

  19. Higher-order-mode (HOM) power in elliptical superconducting cavities for intense pulsed proton accelerators

    CERN Document Server

    Sang Ho Kim; Dong O Jeon; Sundeli, R

    2002-01-01

    In linacs for intense pulsed proton accelerators, the beam has a multiple time-structure, and each beam time-structure generates resonance. When a higher-order mode (HOM) is near these resonance frequencies, the induced voltage could be large and accordingly the resulting HOM power, too. In order to understand the effects of a complex beam time-structure on the mode excitations and the resulting HOM powers in elliptical superconducting cavities, analytic expressions are developed, with which the beam-induced voltage and corresponding power are explored, taking into account the properties of HOM frequency behavior in elliptical superconducting cavities. The results and understandings from this analysis are presented with the beam parameters of the Spallation Neutron Source (SNS) superconducting linac.

  20. HomPPI: a class of sequence homology based protein-protein interface prediction methods

    Directory of Open Access Journals (Sweden)

    Dobbs Drena

    2011-06-01

    Full Text Available Abstract Background Although homology-based methods are among the most widely used methods for predicting the structure and function of proteins, the question as to whether interface sequence conservation can be effectively exploited in predicting protein-protein interfaces has been a subject of debate. Results We studied more than 300,000 pair-wise alignments of protein sequences from structurally characterized protein complexes, including both obligate and transient complexes. We identified sequence similarity criteria required for accurate homology-based inference of interface residues in a query protein sequence. Based on these analyses, we developed HomPPI, a class of sequence homology-based methods for predicting protein-protein interface residues. We present two variants of HomPPI: (i NPS-HomPPI (Non partner-specific HomPPI, which can be used to predict interface residues of a query protein in the absence of knowledge of the interaction partner; and (ii PS-HomPPI (Partner-specific HomPPI, which can be used to predict the interface residues of a query protein with a specific target protein. Our experiments on a benchmark dataset of obligate homodimeric complexes show that NPS-HomPPI can reliably predict protein-protein interface residues in a given protein, with an average correlation coefficient (CC of 0.76, sensitivity of 0.83, and specificity of 0.78, when sequence homologs of the query protein can be reliably identified. NPS-HomPPI also reliably predicts the interface residues of intrinsically disordered proteins. Our experiments suggest that NPS-HomPPI is competitive with several state-of-the-art interface prediction servers including those that exploit the structure of the query proteins. The partner-specific classifier, PS-HomPPI can, on a large dataset of transient complexes, predict the interface residues of a query protein with a specific target, with a CC of 0.65, sensitivity of 0.69, and specificity of 0.70, when homologs of

  1. High-power RF window and coupler development for the PEP-II B Factory

    International Nuclear Information System (INIS)

    Neubauer, M.; Fant, K.; Hodgson, J.; Judkins, J.; Schwarz, H.; Rimmer, R.A.

    1995-05-01

    We describe the fabrication and testing of the RF windows designed to transmit power to the PEP-II 476 MHz cavities. Design choices to maximize the reliability of the window are discussed. Fabrication technologies for the window are described and finite-element analysis of the assembly process is presented. Conditioning and high-power testing of the window are discussed. Design of the coupler assembly including the integration of the window and other components is reported

  2. Study of a power coupler for superconducting RF cavities used in high intensity proton accelerator

    International Nuclear Information System (INIS)

    Souli, M.

    2007-07-01

    The coaxial power coupler needed for superconducting RF cavities used in the high energy section of the EUROTRANS driver should transmit 150 kW (CW operation) RF power to the protons beam. The calculated RF and dielectric losses in the power coupler (inner and outer conductor, RF window) are relatively high. Consequently, it is necessary to design very carefully the cooling circuits in order to remove the generated heat and to ensure stable and reliable operating conditions for the coupler cavity system. After calculating all type of losses in the power coupler, we have designed and validated the inner conductor cooling circuit using numerical simulations results. We have also designed and optimized the outer conductor cooling circuit by establishing its hydraulic and thermal characteristics. Next, an experiment dedicated to study the thermal interaction between the power coupler and the cavity was successfully performed at CRYOHLAB test facility. The critical heat load Qc for which a strong degradation of the cavity RF performance was measured leading to Q c in the range 3 W-5 W. The measured heat load will be considered as an upper limit of the residual heat flux at the outer conductor cold extremity. A dedicated test facility was developed and successfully operated for measuring the performance of the outer conductor heat exchanger using supercritical helium as coolant. The test cell used reproduces the realistic thermal boundary conditions of the power coupler mounted on the cavity in the cryo-module. The first experimental results have confirmed the excellent performance of the tested heat exchanger. The maximum residual heat flux measured was 60 mW for a 127 W thermal load. As the RF losses in the coupler are proportional to the incident RF power, we can deduce that the outer conductor heat exchanger performance is continued up to 800 kW RF power. Heat exchanger thermal conductance has been identified using a 2D axisymmetric thermal model by comparing

  3. Cpl6: The New Extensible, High-Performance Parallel Coupler forthe Community Climate System Model

    Energy Technology Data Exchange (ETDEWEB)

    Craig, Anthony P.; Jacob, Robert L.; Kauffman, Brain; Bettge,Tom; Larson, Jay; Ong, Everest; Ding, Chris; He, Yun

    2005-03-24

    Coupled climate models are large, multiphysics applications designed to simulate the Earth's climate and predict the response of the climate to any changes in the forcing or boundary conditions. The Community Climate System Model (CCSM) is a widely used state-of-art climate model that has released several versions to the climate community over the past ten years. Like many climate models, CCSM employs a coupler, a functional unit that coordinates the exchange of data between parts of climate system such as the atmosphere and ocean. This paper describes the new coupler, cpl6, contained in the latest version of CCSM,CCSM3. Cpl6 introduces distributed-memory parallelism to the coupler, a class library for important coupler functions, and a standardized interface for component models. Cpl6 is implemented entirely in Fortran90 and uses Model Coupling Toolkit as the base for most of its classes. Cpl6 gives improved performance over previous versions and scales well on multiple platforms.

  4. Zeno effect and switching of solitons in nonlinear couplers

    DEFF Research Database (Denmark)

    Abdullaev, F Kh; Konotop, V V; Ögren, Magnus

    2011-01-01

    The Zeno effect is investigated for soliton type pulses in a nonlinear directional coupler with dissipation. The effect consists in increase of the coupler transparency with increase of the dissipative losses in one of the arms. It is shown that localized dissipation can lead to switching...

  5. Ultrashort hybrid metal-insulator plasmonic directional coupler.

    Science.gov (United States)

    Noghani, Mahmoud Talafi; Samiei, Mohammad Hashem Vadjed

    2013-11-01

    An ultrashort plasmonic directional coupler based on the hybrid metal-insulator slab waveguide is proposed and analyzed at the telecommunication wavelength of 1550 nm. It is first analyzed using the supermode theory based on mode analysis via the transfer matrix method in the interaction region. Then the 2D model of the coupler, including transition arms, is analyzed using a commercial finite-element method simulator. The hybrid slab waveguide is composed of a metallic layer of silver and two dielectric layers of silica (SiO2) and silicon (Si). The coupler is optimized to have a minimum coupling length and to transfer maximum power considering the layer thicknesses as optimization variables. The resulting coupling length in the submicrometer region along with a noticeable power transfer efficiency are advantages of the proposed coupler compared to previously reported plasmonic couplers.

  6. A novel bridge coupler for SSC coupled cavity linac

    International Nuclear Information System (INIS)

    Yao, C.G.; Chang, C.R.; Funk, W.

    1992-01-01

    A novel magnetically coupled multi-cavity bridge coupler is proposed for SSC Coupled-Cavity-Linac (CCL). The bridge coupler is a five cell disc-loaded waveguide with a small central aperture used for measurement and two large curved coupling slots near the edge on each disc. The two coupling slots on the adjacent disc are rotated 90 degrees in orientation to reduce the direct coupling. This type of structure is capable of producing very large coupling (>10% in our longest bridge coupler). Also because of the small opening on the discs, the high-order-modes are very far (> 300 MHz) above the operating mode. Thus for long bridge couplers, the magnetic coupled structure should provide maximum coupling with minimum mode mixing problems. In this paper both physics and engineering issues of this new bridge coupler are presented. (Author) 5 refs., 2 tabs., 6 figs

  7. Apodized grating coupler using fully-etched nanostructures

    International Nuclear Information System (INIS)

    Wu Hua; Li Chong; Guo Xia; Li Zhi-Yong

    2016-01-01

    A two-dimensional apodized grating coupler for interfacing between single-mode fiber and photonic circuit is demonstrated in order to bridge the mode gap between the grating coupler and optical fiber. The grating grooves of the grating couplers are realized by columns of fully etched nanostructures, which are utilized to digitally tailor the effective refractive index of each groove in order to obtain the Gaussian-like output diffractive mode and then enhance the coupling efficiency. Compared with that of the uniform grating coupler, the coupling efficiency of the apodized grating coupler is increased by 4.3% and 5.7%, respectively, for the nanoholes and nanorectangles as refractive index tunes layer. (paper)

  8. Fiber-optic couplers as displacement sensors

    Science.gov (United States)

    Baruch, Martin C.; Gerdt, David W.; Adkins, Charles M.

    2003-04-01

    We introduce the novel concept of using a fiber-optic coupler as a versatile displacement sensor. Comparatively long fiber-optic couplers, with a coupling region of approximately 10 mm, are manufactured using standard communication SM fiber and placed in a looped-back configuration. The result is a displacement sensor, which is robust and highly sensitive over a wide dynamic range. This displacement sensor resolves 1-2 μm over distances of 1-1.5 mm and is characterized by the essential absence of a 'spring constant' plaguing other strain gauge-type sensors. Consequently, it is possible to couple to extremely weak vibrations, such as the skin displacement affected by arterial heart beat pulsations. Used as a wrist-worn heartbeat monitor, the fidelity of the arterial pulse signal has been shown to be so high that it is possible to not only determine heartbeat and breathing rates, but to implement a new single-point blood pressure measurement scheme which does not squeeze the arm. In an application as a floor vibration sensor for the non-intrusive monitoring of independently living elderly, the sensor has been shown to resolve the distinct vibration spectra of different persons and different events.

  9. Bi-directional triplexer with butterfly MMI coupler using SU-8 polymer waveguides

    Science.gov (United States)

    Mareš, David; Jeřábek, Vítězslav; Prajzler, Václav

    2015-01-01

    We report about a design of a bi-directional planar optical multiplex/demultiplex filter (triplexer) for the optical part of planar hybrid WDM bi-directional transceiver in fiber-to-the-home (FTTH) PON applications. The triplex lightwave circuit is based on the Epoxy Novolak Resin SU-8 waveguides on the silica-on-silicon substrate with Polymethylmethacrylate cladding layer. The triplexer is comprised of a linear butterfly concept of multimode interference (MMI) coupler separating downstream optical signals of 1490 nm and 1550 nm. For the upstream channel of 1310 nm, an additional directional coupler (DC) is used to add optical signal of 1310 nm propagating in opposite direction. The optical triplexer was designed and optimized using beam propagation method. The insertion losses, crosstalk attenuation, and extinction ratio for all three inputs/outputs were investigated. The intended triplexer was designed using the parameters of the separated DC and MMI filter to approximate the idealized direct connection of both devices.

  10. Thermal-Mechanical Study of 3.9 GHz CW Coupler and Cavity for LCLS-II Project

    Energy Technology Data Exchange (ETDEWEB)

    Gonin, Ivan [Fermilab; Harms, Elvin [Fermilab; Khabiboulline, Timergali [Fermilab; Solyak, Nikolay [Fermilab; Yakovlev, Vyacheslav [Fermilab

    2017-05-01

    Third harmonic system was originally developed by Fermilab for FLASH facility at DESY and then was adopted and modified by INFN for the XFEL project [1-3]. In contrast to XFEL project, all cryomodules in LCLS-II project will operate in CW regime with higher RF average power for 1.3 GHz and 3.9 GHz cavities and couplers. Design of the cavity and fundamental power coupler has been modified to satisfy LCLS-II requirements. In this paper we discuss the results of COMSOL thermal and mechanical analysis of the 3.9 GHz coupler and cavity to verify proposed modifica-tion of the design. For the dressed cavity we present simulations of Lorentz force detuning, helium pressure sensitivity df/dP and major mechanical resonances.

  11. A grating coupler with a trapezoidal hole array for perfectly vertical light coupling between optical fibers and waveguides

    Science.gov (United States)

    Mizutani, Akio; Eto, Yohei; Kikuta, Hisao

    2017-12-01

    A grating coupler with a trapezoidal hole array was designed and fabricated for perfectly vertical light coupling between a single-mode optical fiber and a silicon waveguide on a silicon-on-insulator (SOI) substrate. The grating coupler with an efficiency of 53% was computationally designed at a 1.1-µm-thick buried oxide (BOX) layer. The grating coupler and silicon waveguide were fabricated on the SOI substrate with a 3.0-µm-thick BOX layer by a single full-etch process. The measured coupling efficiency was 24% for TE-polarized light at 1528 nm wavelength, which was 0.69 times of the calculated coupling efficiency for the 3.0-µm-thick BOX layer.

  12. Development of 20 kW input power coupler for 1.3 GHz ERL main linac. Component test at 30 kW IOT test stand

    International Nuclear Information System (INIS)

    Sakai, Hiroshi; Umemori, Kensei; Sakanaka, Shogo; Takahashi, Takeshi; Furuya, Takaaki; Shinoe, Kenji; Ishii, Atsushi; Nakamura, Norio; Sawamura, Masaru

    2009-01-01

    We started to develop an input coupler for a 1.3 GHz ERL superconducting cavity. Required input power is about 20 kW for the cavity acceleration field of 20 MV/m and the beam current of 100 mA in energy recovery operation. The input coupler is designed based on the STF-BL input coupler and some modifications are applied to the design for the CW 20 kW power operation. We fabricated input coupler components such as ceramic windows and bellows and carried out the high-power test of the components by using a 30 kW IOT power source and a test stand constructed for the highpower test. In this report, we mainly describe the results of the high-power test of ceramic window and bellows. (author)

  13. Study of thermal interaction between a 150 kW CW power coupler and a superconducting 704 MHz elliptical cavity

    Energy Technology Data Exchange (ETDEWEB)

    Souli, M. [Institut de Physique Nucleaire d' Orsay, CNRS/IN2P3, Orsay (France)]. E-mail: souli@ipno.in2p3.fr; Fouaidy, M. [Institut de Physique Nucleaire d' Orsay, CNRS/IN2P3, Orsay (France); Saugnac, H. [Institut de Physique Nucleaire d' Orsay, CNRS/IN2P3, Orsay (France); Szott, P. [Institut de Physique Nucleaire d' Orsay, CNRS/IN2P3, Orsay (France); Gandolfo, N. [Institut de Physique Nucleaire d' Orsay, CNRS/IN2P3, Orsay (France); Bousson, S. [Institut de Physique Nucleaire d' Orsay, CNRS/IN2P3, Orsay (France); Braud, D. [CEA Saclay, DSM/DAPNIA/SACM, 91191 Gif sur Yvette (France); Charrier, J.P. [CEA Saclay, DSM/DAPNIA/SACM, 91191 Gif sur Yvette (France); Roudier, D. [CEA Saclay, DSM/DAPNIA/SACM, 91191 Gif sur Yvette (France); Sahuquet, P. [CEA Saclay, DSM/DAPNIA/SACM, 91191 Gif sur Yvette (France); Visentin, B. [CEA Saclay, DSM/DAPNIA/SACM, 91191 Gif sur Yvette (France)

    2006-07-15

    The power coupler needed for {beta} = 0.65 SRF elliptical cavities dedicated to the driver of XADS (eXperimental Accelerator Driven System) should transmit a CW RF power of 150 kW to a 10 mA proton beam. The estimated average values of the RF losses in the coupler are 130 W (respectively 46 W) for the inner (respectively outer) conductor in SW mode. Due to such high values of the RF losses, it is necessary to very carefully design and optimize the cooling circuits of the coupler in order to efficiently remove the generated heat and to reduce the thermal load to the cavity operating at T = 2 K. An experiment simulating the thermal interaction between the power coupler and a 704 MHz SRF five cells cavity was performed in the CRYHOLAB test facility in order to determine the critical heat load that can be sustained by the cavity without degradation of its RF performance. Experimental data are compared to numerical simulation results obtained with the Finite Element Method code COSMOS/M. These data allow us also to perform in situ measurements of the thermal parameters needed in the thermal model of the coupler (thermal conductivity, thermal contact resistance). These data are used to validate numerical simulations.

  14. Ultra-Broadband Silicon-Wire Polarization Beam Combiner/Splitter Based on a Wavelength Insensitive Coupler With a Point-Symmetrical Configuration

    OpenAIRE

    Uematsu, Takui; Kitayama, Tetsuya; Ishizaka, Yuhei; Saitoh, Kunimasa

    2014-01-01

    An ultrabroadband silicon wire polarization beam combiner/splitter (PBCS) based on a wavelength-insensitive coupler is proposed. The proposed PBCS consists of three identical directional couplers and two identical delay lines. We design the PBCS using the 3-D finite element method. Numerical simulations show that the proposed PBCS can achieve the transmittance of more than 90% over a wide wavelength range from 1450 to 1650 nm for both TE and TM polarized modes.

  15. Structural effects on electromagnetic flow coupler performance

    International Nuclear Information System (INIS)

    Aoyama, Goro; Yokota, Norikatsu; Mine, Masao; Watanabe, Takashi; Takuma, Tadasu; Takenaka, Kiyoshi.

    1992-01-01

    A prototype electromagnetic flow coupler was tested using 300degC liquid sodium to estimate the effect on performance of generator flow velocity, magnetic flux density, magnetic core length and bus bar length. Its performance was not affected by changes in fluid velocity and magnetic flux density up to 8.3 m/s and 0.51 T, respectively. Besides the experiments, a two-dimensional numerical analysis program based on Ohm's law and the current continuity equation was prepared to estimate the effects of magnetic core length and bus bar construction. The current transferred from the generator to the pump, the current transfer ratio, increased by lengthening the magnetic core being a maximum of 0.706 for a 100 mm core and 0.764 for a 300 mm core. The numerical results showed that the presence of the bus bar in the outer region of the magnetic core gave inferior performance to that in its absence. (author)

  16. Efficient waveguide coupler based on metal materials

    Science.gov (United States)

    Wu, Wenjun; Yang, Junbo; Chang, Shengli; Zhang, Jingjing; Lu, Huanyu

    2015-10-01

    Because of the diffraction limit of light, the scale of optical element stays in the order of wavelength, which makes the interface optics and nano-electronic components cannot be directly matched, thus the development of photonics technology encounters a bottleneck. In order to solve the problem that coupling of light into the subwavelength waveguide, this paper proposes a model of coupler based on metal materials. By using Surface Plasmon Polaritons (SPPs) wave, incident light can be efficiently coupled into waveguide of diameter less than 100 nm. This paper mainly aims at near infrared wave band, and tests a variety of the combination of metal materials, and by changing the structural parameters to get the maximum coupling efficiency. This structure splits the plane incident light with wavelength of 864 nm, the width of 600 nm into two uniform beams, and separately coupled into the waveguide layer whose width is only about 80 nm, and the highest coupling efficiency can reach above 95%. Using SPPs structure will be an effective method to break through the diffraction limit and implement photonics device high-performance miniaturization. We can further compress the light into small scale fiber or waveguide by using the metal coupler, and to save the space to hold more fiber or waveguide layer, so that we can greatly improve the capacity of optical communication. In addition, high-performance miniaturization of the optical transmission medium can improve the integration of optical devices, also provide a feasible solution for the photon computer research and development in the future.

  17. WAVEGUIDE COUPLER KICK TO BEAM BUNCH AND CURRENT DEPENDENCY ON SRF CAVITIES

    International Nuclear Information System (INIS)

    Genfa Wu; Haipeng Wang; Charles Reece; Robert Rimmer

    2008-01-01

    JLAB SRF cavities employ waveguide type fundamental power couplers (FPC). The FPC design for the 7-cell upgrade cavities was optimized to minimize the dipole field kick. For continuous wave (CW) operation, the forwarding RF power will be at different magnitude to drive the different beam current and cavity gradient. This introduces some deviation from optimized FPC field for varying beam loading. This article analyzes the beam behavior both in centroid kick and head-tail kick under different beam loading conditions

  18. Grating-assisted surface acoustic wave directional couplers

    Science.gov (United States)

    Golan, G.; Griffel, G.; Seidman, A.; Croitoru, N.

    1991-07-01

    Physical properties of novel grating-assisted Y directional couplers are examined using the coupled-mode theory. A general formalism for the analysis of the lateral perturbed directional coupler properties is presented. Explicit expressions for waveguide key parameters such as coupling length, grating period, and other structural characterizations, are obtained. The influence of other physical properties such as time and frequency response or cutoff conditions are also analyzed. A plane grating-assisted directional coupler is presented and examined as a basic component in the integrated acoustic technology.

  19. Ultra-compact silicon nitride grating coupler for microscopy systems

    OpenAIRE

    Zhu, Yunpeng; Wang, Jie; Xie, Weiqiang; Tian, Bin; Li, Yanlu; Brainis, Edouard; Jiao, Yuqing; Van Thourhout, Dries

    2017-01-01

    Grating couplers have been widely used for coupling light between photonic chips and optical fibers. For various quantum-optics and bio-optics experiments, on the other hand, there is a need to achieve good light coupling between photonic chips and microscopy systems. Here, we propose an ultra-compact silicon nitride (SiN) grating coupler optimized for coupling light from a waveguide to a microscopy system. The grating coupler is about 4 by 2 mu m(2) in size and a 116 nm 1 dB bandwidth can be...

  20. The Spectroscopy Analysis of Natural Radionuclide in Some Agriculture Regions Homs City

    International Nuclear Information System (INIS)

    Soufan, A.

    2009-01-01

    Gamma Spectroscopy was utilized for assessment the radionuclide concentration ( K 40 , Ra 226 , Th 232 ..) in some agricultures regions in Homs City. The spectroscopy analysis carried on different samples from agricultures soil, black soil, red soil and........ and White soil chosen from different regions in Homs area. The study shows that all samples contain K 40 in large quantities, and Ra 226 , Th 232 in small quantities. The measurements showed that the dose varies between 942μSv/y for black soil and 524μSv/y for white soil. These results of the measurements have indicated that natural radioactivity in agricultures soils in Homs area are relatively normal and less than that estimated by another country in the world. (author)

  1. HOM [higher order mode] losses at the IR [interaction region] of the B-factory

    International Nuclear Information System (INIS)

    Heifets, S.

    1990-08-01

    Masking at the interaction region (IR) will presumably reduce the synchrotron radiation background in the detector. One possible layout of the IR for B-factory shows a rather complicated system of masks. A bunch passing each mask will generate RF waves. These waves (called usually higher order modes, HOM-s) will be absorbed in the beam pipe wall producing additional heating and, interacting with the beam, kicking particles in the radial and azimuthal directions. This may change the bunch motion and its emittance. These effects are estimated in the present note

  2. Higher Order Modes HOM's in Coupled Cavities of the Flash Module ACC39

    International Nuclear Information System (INIS)

    Shinton, I.R.R.

    2012-01-01

    We analyse the higher order modes (HOM's) in the 3.9GHz bunch shaping cavities installed in the FLASH facility at DESY. A suite of finite element computer codes (including HFSS and ACE3P) and globalised scattering matrix calculations (GSM) are used to investigate the modes in these cavities. This study is primarily focused on the dipole component of the multiband expansion of the wakefield, with the emphasis being on the development of a HOM-based BPM system for ACC39. Coupled inter-cavity modes are simulated together with a limited band of trapped modes.

  3. Unconsumed precursors and couplers after formation of oxidative hair dyes

    DEFF Research Database (Denmark)

    Rastogi, Suresh Chandra; Søsted, Heidi; Johansen, Jeanne Duus

    2006-01-01

    Contact allergy to hair dye ingredients, especially precursors and couplers, is a well-known entity among consumers having hair colouring done at home or at a hairdresser. The aim of the present investigation was to estimate consumer exposure to some selected precursors (p-phenylenediamine, toluene......-2,5-diamine) and couplers (3-aminophenol, 4-aminophenol, resorcinol) of oxidative hair dyes during and after hair dyeing. Concentrations of unconsumed precursors and couplers in 8 hair dye formulations for non-professional use were investigated, under the conditions reflecting hair dyeing. Oxidative...... hair dye formation in the absence of hair was investigated using 6 products, and 2 products were used for experimental hair dyeing. In both presence and absence of hair, significant amounts of unconsumed precursors and couplers remained in the hair dye formulations after final colour development. Thus...

  4. An RF input coupler system for the CEBAF energy upgrade cryomodule

    International Nuclear Information System (INIS)

    J.R. Delayen; L.R. Doolittle; T. Hiatt; J. Hogan; J. Mammosser; L. Phillips; J. Preble; W.J. Schneider; G. Wu

    1999-01-01

    Long term plans for CEBAF at Jefferson Lab call for achieving 12 GeV in the middle of the next decade and 24 GeV after 2010. Thus an upgraded cryomodule to more than double the present voltage is under development. A new waveguide coupler system has been designed and prototypes are currently being developed. This coupler, unlike the original, has a nominal Q ext of 2.1 x 10 7 , reduced sensitivity of Q ext to mechanical deformation, reduced field asymmetry within the beam envelope, freedom from window arcing with a single window at 300 K, and is capable of transmitting 6kW CW both traveling wave and in full reflection

  5. Compact broadband polarization beam splitter using a symmetric directional coupler with sinusoidal bends.

    Science.gov (United States)

    Zhang, Fan; Yun, Han; Wang, Yun; Lu, Zeqin; Chrostowski, Lukas; Jaeger, Nicolas A F

    2017-01-15

    We design and demonstrate a compact broadband polarization beam splitter (PBS) using a symmetric directional coupler with sinusoidal bends on a silicon-on-insulator platform. The sinusoidal bends in our PBS suppress the power exchange between two parallel symmetric strip waveguides for the transverse-electric (TE) mode, while allowing for the maximum power transfer to the adjacent waveguide for the transverse-magnetic (TM) mode. Our PBS has a nominal coupler length of 8.55 μm, and it has an average extinction ratio (ER) of 12.0 dB for the TE mode, an average ER of 20.1 dB for the TM mode, an average polarization isolation (PI) of 20.6 dB for the through port, and an average PI of 11.5 dB for the cross port, all over a bandwidth of 100 nm.

  6. Investigations and Simulations of All optical Switches in linear state Based on Photonic Crystal Directional Coupler

    Directory of Open Access Journals (Sweden)

    S. Maktoobi

    2014-10-01

    Full Text Available Switching is a principle process in digital computers and signal processing systems. The growth of optical signal processing systems, draws particular attention to design of ultra-fast optical switches. In this paper, All Optical Switches in linear state Based On photonic crystal Directional coupler is analyzed and simulated. Among different methods, the finite difference time domain method (FDTD is a preferable method and is used. We have studied the application of photonic crystal lattices, the physics of optical switching and photonic crystal Directional coupler. In this paper, Electric field intensity and the power output that are two factors to improve the switching performance and the device efficiency are investigated and simulated. All simulations are performed by COMSOL software.

  7. Direct UV-written broadband directional broadband planar waveguide couplers

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    We report the fabrication of broadband directional couplers by direct UV-writing. The fabrication process is shown to be beneficial, robust and flexible. The components are compact and show superior performance in terms of loss and broadband operation.......We report the fabrication of broadband directional couplers by direct UV-writing. The fabrication process is shown to be beneficial, robust and flexible. The components are compact and show superior performance in terms of loss and broadband operation....

  8. Low-loss multimode interference couplers for terahertz waves

    Science.gov (United States)

    Themistos, Christos; Kalli, Kyriacos; Komodromos, Michael; Markides, Christos; Quadir, Anita; Rahman, B. M. Azizur; Grattan, Kenneth T. V.

    2012-04-01

    The terahertz (THz) frequency region of the electromagnetic spectrum is located between the traditional microwave spectrum and the optical frequencies, and offers a significant scientific and technological potential in many fields, such as in sensing, in imaging and in spectroscopy. Waveguiding in this intermediate spectral region is a major challenge. Amongst the various THz waveguides suggested, metal-clad plasmonic waveguides and specifically hollow core structures, coated with insulating material are the most promising low-loss waveguides used in both active and passive devices. Optical power splitters are important components in the design of optoelectronic systems and optical communication networks such as Mach-Zehnder Interferometric switches, polarization splitter and polarization scramblers. Several designs for the implementation of the 3dB power splitters have been proposed in the past, such as the directional coupler-based approach, the Y-junction-based devices and the MMI-based approach. In the present paper a novel MMI-based 3dB THz wave splitter is implemented using Gold/polystyrene (PS) coated hollow glass rectangular waveguides. The H-field FEM based full-vector formulation is used here to calculate the complex propagation characteristics of the waveguide structure and the finite element beam propagation method (FE-BPM) and finite difference time domain (FDTD) approach to demonstrate the performance of the proposed 3dB splitter.

  9. Some remarks about monoidal Hom-algebras | Alonso Álvarez ...

    African Journals Online (AJOL)

    Abstract. In this paper, for C a strict braided monoidal category with tensor product , we improve the denition of Hom-associative algebra by removing the multiplicativity condition of the automorphism . After that we state the close connection between the classical notions of (co)algebra, (co)module and Hopf algebra and the ...

  10. Suppression of multipacting in high power RF couplers operating with superconducting cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ostroumov, P.N., E-mail: ostroumov@frib.msu.edu [Facility for Rare Isotope Beams (FRIB), Michigan State University, East Lansing, MI 48824 (United States); Kazakov, S. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Morris, D.; Larter, T.; Plastun, A.S.; Popielarski, J.; Wei, J.; Xu, T. [Facility for Rare Isotope Beams (FRIB), Michigan State University, East Lansing, MI 48824 (United States)

    2017-06-01

    Capacitive input couplers based on a 50 Ω coaxial transmission line are frequently used to transmit RF power to superconducting (SC) resonators operating in CW mode. It is well known that coaxial transmission lines are prone to multipacting phenomenon in a wide range of RF power level and operating frequency. The Facility for Rare Isotope Beams (FRIB) being constructed at Michigan State University includes two types of quarter wave SC resonators (QWR) operating at 80.5 MHz and two types of half wave SC resonators (HWR) operating at 322 MHz. As was reported in ref. [1] a capacitive input coupler used with HWRs was experiencing strong multipacting that resulted in a long conditioning time prior the cavity testing at design levels of accelerating fields. We have developed an insert into 50 Ω coaxial transmission line that provides opportunity to bias the RF coupler antenna and protect the amplifier from the bias potential in the case of breakdown in DC isolation. Two of such devices have been built and are currently used for the off-line testing of 8 HWRs installed in the cryomodule.

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

    Science.gov (United States)

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

    2010-05-01

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

  12. Identification of Human Junctional Adhesion Molecule 1 as a Functional Receptor for the Hom-1 Calicivirus on Human Cells

    Directory of Open Access Journals (Sweden)

    Stanislav V. Sosnovtsev

    2017-02-01

    Full Text Available The Hom-1 vesivirus was reported in 1998 following the inadvertent transmission of the animal calicivirus San Miguel sea lion virus to a human host in a laboratory. We characterized the Hom-1 strain and investigated the mechanism by which human cells could be infected. An expression library of 3,559 human plasma membrane proteins was screened for reactivity with Hom-1 virus-like particles, and a single interacting protein, human junctional adhesion molecule 1 (hJAM1, was identified. Transient expression of hJAM1 conferred susceptibility to Hom-1 infection on nonpermissive Chinese hamster ovary (CHO cells. Virus infection was markedly inhibited when CHO cells stably expressing hJAM were pretreated with anti-hJAM1 monoclonal antibodies. Cell lines of human origin were tested for growth of Hom-1, and efficient replication was observed in HepG2, HuH7, and SK-CO15 cells. The three cell lines (of hepatic or intestinal origin were confirmed to express hJAM1 on their surface, and clustered regularly interspaced short palindromic repeats/Cas9-mediated knockout of the hJAM1 gene in each line abolished Hom-1 propagation. Taken together, our data indicate that entry of the Hom-1 vesivirus into these permissive human cell lines is mediated by the plasma membrane protein hJAM1 as a functional receptor.

  13. Apodized grating coupler using fully-etched nanostructures

    Science.gov (United States)

    Wu, Hua; Li, Chong; Li, Zhi-Yong; Guo, Xia

    2016-08-01

    A two-dimensional apodized grating coupler for interfacing between single-mode fiber and photonic circuit is demonstrated in order to bridge the mode gap between the grating coupler and optical fiber. The grating grooves of the grating couplers are realized by columns of fully etched nanostructures, which are utilized to digitally tailor the effective refractive index of each groove in order to obtain the Gaussian-like output diffractive mode and then enhance the coupling efficiency. Compared with that of the uniform grating coupler, the coupling efficiency of the apodized grating coupler is increased by 4.3% and 5.7%, respectively, for the nanoholes and nanorectangles as refractive index tunes layer. Project supported by the National Natural Science Foundation of China (Grant Nos. 61222501, 61335004, and 61505003), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20111103110019), the Postdoctoral Science Foundation of Beijing Funded Project, China (Grant No. Q6002012201502), and the Science and Technology Research Project of Jiangxi Provincial Education Department, China (Grant No. GJJ150998).

  14. CW all optical self switching in nonlinear chalcogenide nano plasmonic directional coupler

    Science.gov (United States)

    Motamed-Jahromi, Leila; Hatami, Mohsen

    2018-04-01

    In this paper we obtain the coupling coefficient of plasmonic directional coupler (PDC) made up of two parallel monolayer waveguides filled with high nonlinear chalcogenide material for TM mode in continues wave (CW) regime. In addition, we assume each waveguides acts as a perturbation to other waveguide. Four nonlinear-coupled equations are derived. Transfer distances are numerically calculated and used for deriving length of all optical switch. The length of designed switch is in the range of 10-1000 μm, and the switching power is in the range of 1-100 W/m. Obtained values are suitable for designing all optical elements in the integrated optical circuits.

  15. Monolithically integrated fiber-to-the-home diplexers and triplexers using a bilevel etched 2 x 2 optical coupler.

    Science.gov (United States)

    Zhang, Li; Wang, Lei; He, Jian-Jun

    2009-09-01

    A novel design of monolithically integrated diplexers and triplexers for fiber-to-the-home applications is presented. A bilevel etched asymmetrical 2 x 2 optical coupler is analyzed for efficient couplings of both upstream and downstream signals. The design of the diplexer is extended to a triplexer by adding an etched diffraction grating as an additional downstream demultiplexing element. The total size of the integrated diplexer and triplexer is smaller than 500 microm x 500 microm.

  16. Studying quick coupler efficiency in working attachment system of single-bucket power shovel

    Science.gov (United States)

    Duganova, E. V.; Zagorodniy, N. A.; Solodovnikov, D. N.; Korneyev, A. S.

    2018-03-01

    A prototype of a quick-disconnect connector (quick coupler) with an unloaded retention mechanism was developed from the analysis of typical quick couplers used as intermediate elements for power shovels of different manufacturers. A method is presented, allowing building a simulation model of the quick coupler prototype as an alternative to physical modeling for further studies.

  17. CORE-Hom: a powerful and exhaustive database of clinical trials in homeopathy.

    Science.gov (United States)

    Clausen, Jürgen; Moss, Sian; Tournier, Alexander; Lüdtke, Rainer; Albrecht, Henning

    2014-10-01

    The CORE-Hom database was created to answer the need for a reliable and publicly available source of information in the field of clinical research in homeopathy. As of May 2014 it held 1048 entries of clinical trials, observational studies and surveys in the field of homeopathy, including second publications and re-analyses. 352 of the trials referenced in the database were published in peer reviewed journals, 198 of which were randomised controlled trials. The most often used remedies were Arnica montana (n = 103) and Traumeel(®) (n = 40). The most studied medical conditions were respiratory tract infections (n = 126) and traumatic injuries (n = 110). The aim of this article is to introduce the database to the public, describing and explaining the interface, features and content of the CORE-Hom database. Copyright © 2014 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

  18. Diagnostics Upgrades for Investigations of HOM Effects in TESLA-type SCRF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A. H. [Fermilab; Edstrom Jr., D.; Ruan, J. [Fermilab; Thurman-Keup, R. [Fermilab; Shin, Y. [Fermilab; Prieto, P. [Fermilab; Eddy, N. [Fermilab; Carlsten, B. E. [Los Alamos

    2017-08-23

    We describe the upgrades to diagnostic capabilities on the Fermilab Accelerator Science and Technology (FAST) electron linear accelerator that will allow investigations of the effects of high-order modes (HOMs) in SCRF cavities on macropulse-average beam quality. We examine the dipole modes in the first pass-band generally observed in the 1.6-1.9 GHz regime for TESLA-type SCRF cavities due to uniform transverse beam offsets of the electron beam. Such cavities are the basis of the accelerators such as the European XFEL and the proposed MaRIE XFEL facility. Preliminary HOM detector data, prototype BPM test data, and first framing camera OTR data with ~20- micron spatial resolution at 250 pC per bunch will be presented.

  19. Analysis of HOM Problems in the C-ADS Main Linac

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Burn [Chinese Academy of Sciences (CAS), Lanzhou (China). Inst. of Modern Physics; Ng, King Yuen [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2017-05-18

    Excitation of higher-order modes (HOMs) in superconducting cavities may severely affect the operation of the main linac in the Chinese Accelerator Driven System (CADS). Preliminary analysis is made on the effects of beam dynamic, which includes possible longitudinal and transverse emittance enlargements, as well as the possibility of beam breakup. Suggestions are given for further investigation. Comparison is made between the C-ADS and the Fermilab Project X.

  20. On-chip grating coupler array on the SOI platform for fan-in/fan-out of MCFs with low insertion loss and crosstalk

    DEFF Research Database (Denmark)

    Ding, Yunhong; Ye, Feihong; Peucheret, Christophe

    2015-01-01

    We report the design and fabrication of a compact multi-core fiber fan-in/fan-out using a grating coupler array on the SOI platform. The grating couplers are fully-etched, enabling the whole circuit to be fabricated in a single lithography and etching step. Thanks to the apodized design...... for the grating couplers and the introduction of an aluminum reflective mirror, a highest coupling efficiency of -3.8 dB with 3 dB coupling bandwidth of 48 nm and 1.5 dB bandwidth covering the whole C band, together with crosstalk lower than -32 dB are demonstrated. (C)2015 Optical Society of America...

  1. Bessel-function analysis of the optimized star coupler for uniform power splitting.

    Science.gov (United States)

    Song, G Hugh; Park, Mahn Yong

    2004-08-01

    An optimized N x N planar optic star coupler that utilizes directional coupling of arrayed waveguides for uniform power splitting is analyzed on the basis of special properties of the involved Bessel-function series. The analysis has provided a remarkably simple, novel basic design formula for such a device with much needed physical insights into the unique diffraction properties. For the analysis of diffraction from the end of directionally coupled arrayed waveguides, many useful formulas around the Bessel functions, such as the addition theorem and the Kepler-Bessel series, have been given in new forms.

  2. Numerical simulation of waveguide input/output couplers for a planar mm-wave linac cavity

    International Nuclear Information System (INIS)

    Kang, Y.W.

    1994-01-01

    A double-sided planar mm-wave linear accelerating cavity structure has been studied. The input/output couplers for the accelerating cavity structure have been designed using the Hewlett-Packard High Frequency Structure Simulator (HFSS). The program is a frequency domain finite element 3-D field solver and can include matched port boundary conditions. The power transmission property of the structure is calculated in the frequency domain. The dimensions of the, coupling cavities and the irises at the input/output ports are adjusted to have the structure matched to rectangular waveguides. The field distributions in the accelerating structure for the 2π/3-mode traveling wave are shown

  3. High efficiency and broad bandwidth grating coupler between nanophotonic waveguide and fibre

    International Nuclear Information System (INIS)

    Yu, Zhu; Xue-Jun, Xu; Zhi-Yong, Li; Liang, Zhou; Yu-De, Yu; Jin-Zhong, Yu; Wei-Hua, Han; Zhong-Chao, Fan

    2010-01-01

    A high efficiency and broad bandwidth grating coupler between a silicon-on-insulator (SOI) nanophotonic waveguide and fibre is designed and fabricated. Coupling efficiencies of 46% and 25% at a wavelength of 1.55 μm are achieved by simulation and experiment, respectively. An optical 3 dB bandwidth of 45 nm from 1530 nm to 1575 nm is also obtained in experiment. Numerical calculation shows that a tolerance to fabrication error of 10 nm in etch depth is achievable. The measurement results indicate that the alignment error of ±2 μm results in less than 1 dB additional coupling loss. (classical areas of phenomenology)

  4. Nonclassical properties of a contradirectional nonlinear optical coupler

    Energy Technology Data Exchange (ETDEWEB)

    Thapliyal, Kishore [Jaypee Institute of Information Technology, A-10, Sector-62, Noida, UP-201307 (India); Pathak, Anirban, E-mail: anirban.pathak@gmail.com [Jaypee Institute of Information Technology, A-10, Sector-62, Noida, UP-201307 (India); RCPTM, Joint Laboratory of Optics of Palacky University and Institute of Physics of Academy of Science of the Czech Republic, Faculty of Science, Palacky University, 17. listopadu 12, 771 46 Olomouc (Czech Republic); Sen, Biswajit [Department of Physics, Vidyasagar Teachers' Training College, Midnapore 721101 (India); Perřina, Jan [RCPTM, Joint Laboratory of Optics of Palacky University and Institute of Physics of Academy of Science of the Czech Republic, Faculty of Science, Palacky University, 17. listopadu 12, 771 46 Olomouc (Czech Republic); Department of Optics, Palacky University, 17. listopadu 12, 771 46 Olomouc (Czech Republic)

    2014-10-24

    We investigate the nonclassical properties of output fields propagated through a contradirectional asymmetric nonlinear optical coupler consisting of a linear waveguide and a nonlinear (quadratic) waveguide operated by second harmonic generation. In contrast to the earlier results, all the initial fields are considered weak and a completely quantum-mechanical model is used here to describe the system. Perturbative solutions of Heisenberg's equations of motion for various field modes are obtained using Sen–Mandal technique. Obtained solutions are subsequently used to show the existence of single-mode and intermodal squeezing, single-mode and intermodal antibunching, two-mode and multi-mode entanglement in the output of contradirectional asymmetric nonlinear optical coupler. Further, existence of higher order nonclassicality is also established by showing the existence of higher order antibunching, higher order squeezing and higher order entanglement. Variation of observed nonclassical characters with different coupling constants and phase mismatch is discussed. - Highlights: • Nonclassicalities in fields propagating through a directional coupler is studied. • Completely quantum-mechanical description of the coupler is provided. • Analytic solutions of Heisenberg equations of motion for various modes are obtained. • Existence of lower order and higher order entanglement is shown. • Variation of nonclassicalities with phase-mismatch and coupling constants is studied.

  5. Coupler tuning for constant gradient travelling wave accelerating structures

    International Nuclear Information System (INIS)

    Guo Xingkun; Ma Yanyun; Wang Xiulong

    2013-01-01

    The method of the coupler tuning for the constant gradient traveling wave accelerating structure was described and the formula of coupling coefficient p was deduced on the basis of analyzing the existing methods for the constant impedance traveling wave accelerating structures and coupling-cavity chain equivalent circuits. The method and formula were validated by the simulation result by CST and experiment data. (authors)

  6. Coaxial TW window for power couplers and multipactor considerations

    International Nuclear Information System (INIS)

    Hanus, X.; Mosnier, A.

    1996-01-01

    A Traveling Wave coaxial window has been studied for power couplers purposes. The main features, a reduced electrical field in the ceramic and its multipacting free shape are presented. Multipacting simulations results for other window geometries, using a conical or a cylindrical ceramic are also showed. (author)

  7. Directional couplers using long-range surface plasmon polariton waveguides

    DEFF Research Database (Denmark)

    Boltasseva, Alexandra; Bozhevolnyi, Sergey I.

    2006-01-01

    14-nm-thick stripes and a wavelength of 1550 urn, LR-SPP propagation loss is determined for the stripe widths varying from 2 to 12 mu m and is found to be similar to 7 and 5 dB/cm for 10- and 4-mu m-wide stripes, respectively. For the directional couplers based on 14-nm-thick and 8-mu m-wide gold...... stripes and a wavelength of 1570 nm, the coupling lengths of 4.1, 1.9, and 0.8 mm are found for the respective waveguide separations of 8, 4, and 0 mu m. We model the LR-SPP-based directional couplers using the effective-refractive-index method and obtain a good agreement with the experimental results....... The transmission spectra of LR-SPP-based directional couplers are presented demonstrating an efficient (similar to 30 dB) separation of different telecom wavelength bands. Various possibilities for dynamic control of wavelength division/multiplexing with LRSPP-based directional couplers that utilize the thermo...

  8. Conceptual design of an L-band recirculating superconducting traveling wave accelerating structure for ILC

    International Nuclear Information System (INIS)

    Avrakhov, P.; Kanareykin, A.; Liu, Z.; Kazakov, S.; KEK, Tsukuba; Solyak, N.; Yakovlev, V.; Gai, W.

    2007-01-01

    With this paper, we propose the conceptual design of a traveling wave accelerating structure for a superconducting accelerator. The overall goal is to study a traveling wave (TW) superconducting (SC) accelerating structure for ILC that allows an increased accelerating gradient and, therefore reduction of the length of the collider. The conceptual studies were performed in order to optimize the acceleration structure design by minimizing the surface fields inside the cavity of the structure, to make the design compatible with existing technology, and to determine the maximum achievable gain in the accelerating gradient. The proposed solution considers RF feedback system redirecting the accelerating wave that passed through the superconducting traveling wave acceleration (STWA) section back to the input of the accelerating structure. The STWA structure has more cells per unit length than a TESLA structure but provides an accelerating gradient higher than a TESLA structure, consequently reducing the cost. In this paper, the STWA cell shape optimization, coupler cell design and feedback waveguide solution are considered. We also discuss the field flatness in the superconducting TW structure, the HOM modes and multipactor performance have been studied as well. The proposed TW structure design gives an overall 46% gain over the SW ILC structure if the 10 m long TW structure is employed

  9. Comparison of sound transmission in human ears and coupler loaded by audiometric earphones

    DEFF Research Database (Denmark)

    Ciric, Dejan; Hammershøi, Dorte

    2005-01-01

    in the coupler, but since the "ear canal entrance" is not well-defined for the coupler, the mentioned measurements were done at different depths in the coupler. The sound transmission and coupling were described in terms of the pressure division at the entrance of the ear canal and the transmissions in human......, the differences among earphones as well as between human ears and the coupler affect the results of audiometric measurements inducing uncertainty. The influence of these differences is examined by investigating the sound transmission in both human ears and standardized coupler loaded by different audiometric......The thresholds of hearing are usually determined using audiometric earphones. They are calibrated by means of a standardized acoustical coupler. In order to have determined thresholds independent of the earphone type, the coupler should approximate the average human ear closely. Nevertheless...

  10. Suspended mid-infrared fiber-to-chip grating couplers for SiGe waveguides

    Science.gov (United States)

    Favreau, Julien; Durantin, Cédric; Fédéli, Jean-Marc; Boutami, Salim; Duan, Guang-Hua

    2016-03-01

    Silicon photonics has taken great importance owing to the applications in optical communications, ranging from short reach to long haul. Originally dedicated to telecom wavelengths, silicon photonics is heading toward circuits handling with a broader spectrum, especially in the short and mid-infrared (MIR) range. This trend is due to potential applications in chemical sensing, spectroscopy and defense in the 2-10 μm range. We previously reported the development of a MIR photonic platform based on buried SiGe/Si waveguide with propagation losses between 1 and 2 dB/cm. However the low index contrast of the platform makes the design of efficient grating couplers very challenging. In order to achieve a high fiber-to-chip efficiency, we propose a novel grating coupler structure, in which the grating is locally suspended in air. The grating has been designed with a FDTD software. To achieve high efficiency, suspended structure thicknesses have been jointly optimized with the grating parameters, namely the fill factor, the period and the grating etch depth. Using the Efficient Global Optimization (EGO) method we obtained a configuration where the fiber-to-waveguide efficiency is above 57 %. Moreover the optical transition between the suspended and the buried SiGe waveguide has been carefully designed by using an Eigenmode Expansion software. Transition efficiency as high as 86 % is achieved.

  11. Proposal for fabrication-tolerant SOI polarization splitter-rotator based on cascaded MMI couplers and an assisted bi-level taper.

    Science.gov (United States)

    Wang, Jing; Qi, Minghao; Xuan, Yi; Huang, Haiyang; Li, You; Li, Ming; Chen, Xin; Jia, Qi; Sheng, Zhen; Wu, Aimin; Li, Wei; Wang, Xi; Zou, Shichang; Gan, Fuwan

    2014-11-17

    A novel silicon-on-insulator (SOI) polarization splitter-rotator (PSR) with a large fabrication tolerance is proposed based on cascaded multimode interference (MMI) couplers and an assisted mode-evolution taper. The tapers are designed to adiabatically convert the input TM(0) mode into the TE(1) mode, which will output as the TE(0) mode after processed by the subsequent MMI mode converter, 90-degree phase shifter (PS) and MMI 3 dB coupler. The numerical simulation results show that the proposed device has a silicon photonics technology.

  12. Study of a superconducting spoke-type cavity and of its associated power coupler

    International Nuclear Information System (INIS)

    Mielot, Ch.

    2004-12-01

    This work deals with the study of a spoke-type cavity and its associated power coupler. The results of this study are used in the framework of the high power proton linear accelerator of the experimental accelerator-driven system project (XADS). The cavity (F=352 MHz, β=0.35) was tested at 4 K and 2 K. The results at 4 K gave good margins toward XADS requirements that increase the reliability of a spoke based driver. At 2 K the accelerating field reached is the highest in the world for spoke cavities: 16 MV/M. The position and diameter of the coupling have been optimized in order to decrease the HF losses and avoid multi-factor risk. In order to decrease HF losses (taking into account the 20 kW power fed into the cavity) the electric coupling mode has been chosen. Different types of ceramic windows have been studied in order to make this critical point of the coupler reliable: coaxial disk with or without chokes or empty coaxial cylinder. The optimization process focused on the reflected power, the losses in the ceramic and the surface electric field. The risk with chokes has been modeled and studied with the propagation lines theory. A systematic study of the different windows has been done regarding the geometrical parameters. The disk without chokes seems to be a good solution for our application. The power source will be a solid state amplifier (for reliability and modularity reasons). An all over coaxial coupler can be designed and will be fabricated and tested soon. (author)

  13. 2×2 polymeric electro-optic MZI switch using multimode interference couplers

    Science.gov (United States)

    Li, H. P.; Liao, J. K.; Tang, X. G.; Lu, R. G.; Liu, Y. Z.

    2009-11-01

    We present the design of a 2×2 photonic switch operating at 1.55-μm wavelength using electro-optic (EO) polymer waveguides. A Mach-Zehnder interferometer (MZI) is used to implement the proposed switch in which two identical 2×2 multimode interference (MMI) couplers are connected by two identical parallel single mode waveguides (two MZI arms). These two single-mode waveguides with electrodes allow modulating the phase difference between the two MZI arms based on the EO effect. In the proposed switch, the EO polymer, IPC-E/polysulfone, is used for the core layer of optical waveguides. UV15 and NOA61 are employed for the lower and upper cladding layers, respectively. The singlemode waveguide structure and 2×2 MMI coupler have been designed and analyzed for the EO switch. Device performance has been simulated using the beam propagation method. It is found that the switch performance is most sensitive to the MMI width and less sensitive to the MMI length. Optimized structure has been obtained for the 2×2 polymeric EO switch, which has a crosstalk level better than -25 dB and insertion loss lower than -1.8 dB. This performance makes the switch a potential candidate for practical use in photonic systems.

  14. Femtosecond laser inscription of asymmetric directional couplers for in-fiber optical taps and fiber cladding photonics.

    Science.gov (United States)

    Grenier, Jason R; Fernandes, Luís A; Herman, Peter R

    2015-06-29

    Precise alignment of femtosecond laser tracks in standard single mode optical fiber is shown to enable controllable optical tapping of the fiber core waveguide light with fiber cladding photonic circuits. Asymmetric directional couplers are presented with tunable coupling ratios up to 62% and bandwidths up to 300 nm at telecommunication wavelengths. Real-time fiber monitoring during laser writing permitted a means of controlling the coupler length to compensate for micron-scale alignment errors and to facilitate tailored design of coupling ratio, spectral bandwidth and polarization properties. Laser induced waveguide birefringence was harnessed for polarization dependent coupling that led to the formation of in-fiber polarization-selective taps with 32 dB extinction ratio. This technology enables the interconnection of light propagating in pre-existing waveguides with laser-formed devices, thereby opening a new practical direction for the three-dimensional integration of optical devices in the cladding of optical fibers and planar lightwave circuits.

  15. Very short intracavity directional coupler for high-speed communication

    Science.gov (United States)

    Griffel, Giora

    1993-07-01

    We propose a novel intracavity modulator/switch that consists of a directional-coupler located inside a Fabry-Perot cavity. The back mirror of the cavity has a unit reflectivity so that both input and output signals are at the same side. In this way we obtain a two-port, single side element, with coupling length of 83.5 μm, which is the shortest modulation coupler proposed so far. The upper frequency limit due to photon lifetime is 275 GHz, which is well over the bandwidth constraints of microwave lumped structures. A unified approach for the analysis of this device and other similar structures is presented and discussed.

  16. Higher order modes HOMs in coupled cavities of the FLASH module ACC39

    CERN Document Server

    Shinton, I R R; Li, Z; Zhang, P

    2011-01-01

    We analyse the higher order modes (HOM’s) in the 3.9GHz bunch shaping cavities installed in the FLASH facility at DESY. A suite of finite element computer codes (including HFSS and ACE3P) and globalised scattering matrix calculations (GSM) are used to investigate the modes in these cavities. This study is primarily focused on the dipole component of the multiband expansion of the wakefield, with the emphasis being on the development of a HOM-based BPM system for ACC39. Coupled inter-cavity modes are simulated together with a limited band of trapped modes.

  17. Quantum superchemistry in an output coupler of coherent matter waves

    International Nuclear Information System (INIS)

    Jing, H.; Cheng, J.

    2006-01-01

    We investigate the quantum superchemistry or Bose-enhanced atom-molecule conversions in a coherent output coupler of matter waves, as a simple generalization of the two-color photoassociation. The stimulated effects of molecular output step and atomic revivals are exhibited by steering the rf output couplings. The quantum noise-induced molecular damping occurs near a total conversion in a levitation trap. This suggests a feasible two-trap scheme to make a stable coherent molecular beam

  18. All-optical universal logic gates on nonlinear multimode interference coupler using tunable input intensity

    Science.gov (United States)

    Tajaldini, Mehdi; Jafri, Mohd Zubir Mat

    2015-04-01

    The theory of Nonlinear Modal Propagation Analysis Method (NMPA) have shown significant features of nonlinear multimode interference (MMI) coupler with compact dimension and when launched near the threshold of nonlinearity. Moreover, NMPA have the potential to allow studying the nonlinear MMI based the modal interference to explorer the phenomenon that what happen due to the natural of multimode region. Proposal of all-optical switch based NMPA has approved its capability to achieving the all-optical gates. All-optical gates have attracted increasing attention due to their practical utility in all-optical signal processing networks and systems. Nonlinear multimode interference devices could apply as universal all-optical gates due to significant features that NMPA introduce them. In this Paper, we present a novel Ultra-compact MMI coupler based on NMPA method in low intensity compared to last reports either as a novel design method and potential application for optical NAND, NOR as universal gates on single structure for Boolean logic signal processing devices and optimize their application via studding the contrast ratio between ON and OFF as a function of output width. We have applied NMPA for several applications so that the miniaturization in low nonlinear intensities is their main purpose.

  19. Distributed grating-assisted coupler for optical all-dielectric electron accelerator

    Directory of Open Access Journals (Sweden)

    Zhiyu Zhang

    2005-07-01

    Full Text Available A Bragg waveguide consisting of multiple dielectric layers with alternating index of refraction becomes an excellent option to form electron accelerating structure powered by high power laser sources. It provides confinement of a synchronous speed-of-light mode with extremely low loss. However, laser field cannot be coupled into the structure collinearly with the electron beam. There are three requirements in designing input coupler for a Bragg electron accelerator: side coupling, selective mode excitation, and high coupling efficiency. We present a side-coupling scheme using a distributed grating-assisted coupler to inject the laser power into the waveguide. Side coupling is achieved by a grating with a period on the order of an optical wavelength. The phase matching condition results in resonance coupling thus providing selective mode excitation capability. The coupling efficiency is limited by profile matching between the outgoing beam and the incoming beam, which has normally a Gaussian profile. We demonstrate a nonuniform distributed grating structure generating an outgoing beam with a Gaussian profile, therefore, increasing the coupling efficiency.

  20. Low Loss 1×2 Optical Coupler Based on Cosine S-bend with Segmented Waveguides

    Science.gov (United States)

    Yulianti, Ian; Sahmah, Abu; Supa'at, M.; Idrus, Sevia M.; Ridwanto, Muhammad; Al-hetar, Abdulaziz M.

    2011-05-01

    This paper presents an optimization of 1×2 polymer Y-junction optical coupler. The optimized optical coupler comprises straight polymer waveguide as the input waveguide, tapered waveguide, modified cosine S-bend and linear waveguide. At the branching point, N short waveguides with small width are introduced to reduce evanescent field. At operating wavelength of 1550 nm the excess loss of the coupler is ˜0.18 dB. In term of polarization dependence loss (PDL), the proposed coupler also shows a good performance with PDL value of less than 0.015 dB for wavelength range of 1470 nm-1550 nm. The proposed coupler could reduce excess loss more than 25% compared to conventional Y junction optical coupler.

  1. Inexpensive 3dB coupler for POF communication by injection-molding production

    Science.gov (United States)

    Haupt, M.; Fischer, U. H. P.

    2011-01-01

    POFs (polymer optical fibers) gradually replace traditional communication media such as copper and glass within short distance communication systems. Primarily, this is due to their cost-effectiveness and easy handling. POFs are used in various fields of optical communication, e.g. the automotive sector or in-house communication. So far, however, only a few key components for a POF communication network are available. Even basic components, such as splices and couplers, are fabricated manually. Therefore, these circumstances result in high costs and fluctuations in components' performance. Available couplers have high insertion losses due to their manufacturing method. This can only be compensated by higher power budgets. In order to produce couplers with higher performances new fabrication methods are indispensable. A cheap and effective way to produce couplers for POF communication systems is injection molding. The paper gives an overview of couplers available on market, compares their performances, and shows a way to produce couplers by means of injection molding.

  2. High-directionality fiber-chip grating coupler with interleaved trenches and subwavelength index-matching structure.

    Science.gov (United States)

    Benedikovic, Daniel; Alonso-Ramos, Carlos; Cheben, Pavel; Schmid, Jens H; Wang, Shurui; Xu, Dan-Xia; Lapointe, Jean; Janz, Siegfried; Halir, Robert; Ortega-Moñux, Alejandro; Wangüemert-Pérez, J Gonzalo; Molina-Fernández, Iñigo; Fédéli, Jean-Marc; Vivien, Laurent; Dado, Milan

    2015-09-15

    We present the first experimental demonstration of a new fiber-chip grating coupler concept that exploits the blazing effect by interleaving the standard full (220 nm) and shallow etch (70 nm) trenches in a 220 nm thick silicon layer. The high directionality is obtained by controlling the separation between the deep and shallow trenches to achieve constructive interference in the upward direction and destructive interference toward the silicon substrate. Utilizing this concept, the grating directionality can be maximized independent of the bottom oxide thickness. The coupler also includes a subwavelength-engineered index-matching region, designed to reduce the reflectivity at the interface between the injection waveguide and the grating. We report a measured fiber-chip coupling efficiency of -1.3  dB, the highest coupling efficiency achieved to date for a surface grating coupler in a 220 nm silicon-on-insulator platform fabricated in a conventional dual-etch process without high-index overlays or bottom mirrors.

  3. L-shaped fiber-chip grating couplers with high directionality and low reflectivity fabricated with deep-UV lithography.

    Science.gov (United States)

    Benedikovic, Daniel; Alonso-Ramos, Carlos; Pérez-Galacho, Diego; Guerber, Sylvain; Vakarin, Vladyslav; Marcaud, Guillaume; Le Roux, Xavier; Cassan, Eric; Marris-Morini, Delphine; Cheben, Pavel; Boeuf, Frédéric; Baudot, Charles; Vivien, Laurent

    2017-09-01

    Grating couplers enable position-friendly interfacing of silicon chips by optical fibers. The conventional coupler designs call upon comparatively complex architectures to afford efficient light coupling to sub-micron silicon-on-insulator (SOI) waveguides. Conversely, the blazing effect in double-etched gratings provides high coupling efficiency with reduced fabrication intricacy. In this Letter, we demonstrate for the first time, to the best of our knowledge, the realization of an ultra-directional L-shaped grating coupler, seamlessly fabricated by using 193 nm deep-ultraviolet (deep-UV) lithography. We also include a subwavelength index engineered waveguide-to-grating transition that provides an eight-fold reduction of the grating reflectivity, down to 1% (-20  dB). A measured coupling efficiency of -2.7  dB (54%) is achieved, with a bandwidth of 62 nm. These results open promising prospects for the implementation of efficient, robust, and cost-effective coupling interfaces for sub-micrometric SOI waveguides, as desired for large-volume applications in silicon photonics.

  4. Measurement of beam phase at FLASH using HOMs in accelerating cavities

    CERN Document Server

    Shi, Lianliang; Jones, Roger M; Joshi, Nirav

    2017-01-01

    The beam phase relative to the accelerating field is of vital importance for the quality of photon beams produced in modern Free Electron Lasers based on superconducting cavities. Normally, the phase is determined by detecting the transient field induced by the beam. In this way the phase of each cavity is checked and adjusted typically every few months. In this paper, we present an on-line method of beam phase determination, based on higher order modes (HOMs) excited in the 2nd monopole band by the beam inside these cavities. A circuit model of this HOM band is also presented. Various effects on the resolution have been studied. The results indicate that the resolution is strongly dependent on the signal to noise ratio and the sampling rate. Preliminary experimental results, based on a broadband setup, reveal a resolution of ca. 0.1° RMS. These are in good agreement with simulation results. The work will pave the way for a dedicated system of beam phase monitoring, which is under development for the Europea...

  5. Spatial-temporal analysis of building surface temperatures in Hung Hom

    Science.gov (United States)

    Zeng, Ying; Shen, Yueqian

    2015-12-01

    This thesis presents a study on spatial-temporal analysis of building surface temperatures in Hung Hom. Observations were collected from Aug 2013 to Oct 2013 at a 30-min interval, using iButton sensors (N=20) covering twelve locations in Hung Hom. And thermal images were captured in PolyU from 05 Aug 2013 to 06 Aug 2013. A linear regression model of iButton and thermal records is established to calibrate temperature data. A 3D modeling system is developed based on Visual Studio 2010 development platform, using ArcEngine10.0 component, Microsoft Access 2010 database and C# programming language. The system realizes processing data, spatial analysis, compound query and 3D face temperature rendering and so on. After statistical analyses, building face azimuths are found to have a statistically significant relationship with sun azimuths at peak time. And seasonal building temperature changing also corresponds to the sun angle and sun azimuth variations. Building materials are found to have a significant effect on building surface temperatures. Buildings with lower albedo materials tend to have higher temperatures and larger thermal conductivity material have significant diurnal variations. For the geographical locations, the peripheral faces of campus have higher temperatures than the inner faces during day time and buildings located at the southeast are cooler than the western. Furthermore, human activity is found to have a strong relationship with building surface temperatures through weekday and weekend comparison.

  6. Ultra-low loss nano-taper coupler for Silicon-on-Insulator ridge waveguide

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    A nano-taper coupler is optimized specially for the transverse-magnetic mode for interfacing light between a silicon-on-insulator ridge waveguide and a single-mode fiber. An ultra-low coupling loss of ~0.36dB is achieved for the nano-taper coupler.......A nano-taper coupler is optimized specially for the transverse-magnetic mode for interfacing light between a silicon-on-insulator ridge waveguide and a single-mode fiber. An ultra-low coupling loss of ~0.36dB is achieved for the nano-taper coupler....

  7. Broadband photonic crystal fiber coupler with polarization selection of coupling ratio

    Science.gov (United States)

    Jaroszewicz, Leszek R.; Stasiewicz, Karol A.; Marć, Paweł; Szymański, Michał

    2010-09-01

    In the paper a new broadband photonic crystal fiber coupler is presented. The proper application of the biconical taper technology has been used for manufacturing the coupler without air holes collapse in LMA10 fiber (NKT Photonics Crystal). This coupler, operates in the weakly coupling condition, protects coupling operation in range from 900 nm to 1700 nm. The coupling ratio between output arms is depending on wavelength and can be tuning by selection the proper input state of polarization. It gives opportunity to use the broadband crystal fiber coupler in many applications in which it is necessary to tune a coupling between output arms during the measurement.

  8. HOM (higher-order mode) test of the storage ring single-cell cavity with a 20-MeV e- beam for the Advanced Photon Source (APS)

    International Nuclear Information System (INIS)

    Song, J.; Kang, Y.W.; Kustom, R.

    1993-01-01

    To test the effectiveness of damping techniques of the APS storage ring single-cell cavity, a beamline has been designed and assembled to use the ANL Chemistry Division linac beam (20-MeV, FWHM of 20 ps). A single-cell cavity will be excited by the electron beam to investigate the effect on higher-order modes (HOMs) with and without coaxial dampers (H-loop damper, E-probe damper), and wideband aperture dampers. In order for the beam to propagate on- and off-center of the cavity, the beamline consists of two sections -- a beam collimating section and a cavity measurement section -- separated by two double Aluminum foil windows. RF cavity measurements were made with coupling loops and E-probes. The results are compared with both the TBCI calculations and 'cold' measurements with the bead-perturbation method. The data acquisition system and beam diagnostics will be described in a separate paper

  9. USING THE SCRAP TIRES TO PRODUCE A FLEXIBLE COUPLER

    Directory of Open Access Journals (Sweden)

    Tahsean A. Hussain

    2018-01-01

    Full Text Available The scrap tires considered a problematic source of waste, the old rubber tires causes a big environmental problem that is need much money and effort to disposes it safely. In Iraq there are more than two million used tires disposed to the environment annually. one of the tire’s recycling methods is the use of tire layers to produce a new rubber parts used in the engineering and industrial purposes as the bridges and machines dampers, this trend of recycling doesn’t take a sufficient care comparing with the other uses. There are a lot of studies conducted in these field, these studies suggests many methods to manage the huge number of scrap tires, the current paper aims to use the old rubber tires in engineering purposes (especially as a coupler joins the motor or engines with the other equipment as electric dynamo or pumps, the study focusing on the mechanical properties of a strip from a used tires and comparing with one prepared in the lab., and suggesting a new method to use as an engineering parts (for example the coupler lays between the IC engine and the dynamo of an electric generator. One of the results obtained from the experiments, there is no significant difference between the mechanical properties of the old and the new strip, (in the tensile test, the breaking force of the -Lab. tensile specimen- is 137 N whereas the specimen of old tire have a breaking force 113.27 N, but they are same in the elongation. A computational example is suggested to estimate the dimensions of a flexible coupler use an old tire pieces.

  10. Further Clarifying Proximal Withdrawal States and the Turnover Criterion Space: Comment on Hom, Mitchell, Lee, and Griffeth (2012)

    Science.gov (United States)

    Maertz, Carl P., Jr.

    2012-01-01

    In "Reviewing Employee Turnover: Focusing on Proximal Withdrawal States and an Expanded Criterion," Hom, Mitchell, Lee, and Griffeth (2012) brought together many of the most important content and process factors in the employee turnover literature. In this paper, I attempt to clarify the true contributions of this framework for the turnover area…

  11. Changes in antioxidant and fruit quality in hot water-treated ‘Hom Thong’ banana fruit during storage

    Science.gov (United States)

    The effects of hot water treatment on antioxidant phytochemicals and fruit quality were investigated in banana fruit of cv. Gros Michel (Musa acuminata, AAA Group, locally called cv. Hom Thong) by immersing fruits in hot water (50 'C) for 10 min, before storage at 25 'C for 10 days or 14 'C for 8 da...

  12. Preliminary design of high-power wave-guide/transmission system for multimegawatt CW requirements of 100 MeV proton Linac

    International Nuclear Information System (INIS)

    Shrivastava, Purushottam; Wanmode, Y.D.; Hannurkar, P.R.

    2002-01-01

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

  13. Acoustic Coupler for the Acquisition of Coronary Artery Murmurs

    DEFF Research Database (Denmark)

    Zimmermann, Niels Henrik; Schmidt, Samuel; Hansen, John

    to record heart sound in the diastolic period with a sound pressure level approximately 30 dB above the noise floor of the microphone and recording system in the frequency range from 200-700 Hz. The capability of the sensor to record diastolic heart sound in the relevant frequency range indicates...... and the microphone used was evaluated through a large study, where the coupler was used for recording the murmur sound from 464 heart patients. The power spectrum of the diastolic heart sounds was analyzed to determine the characteristics of the frequency spectrum. The preliminary results show, that it was possible...

  14. Integrated optical isolators based on two-mode interference couplers

    International Nuclear Information System (INIS)

    Sun, Yiling; Zhou, Haifeng; Jiang, Xiaoqing; Hao, Yinlei; Yang, Jianyi; Wang, Minghua

    2010-01-01

    This paper presents an optical waveguide isolator based on two-mode interference (TMI) couplers, by utilizing the magneto-optical nonreciprocal phase shift (NPS). The operating principle of this device is to utilize the difference between the nonreciprocal phase shifts of the two lowest-order modes. A two-dimensional (2D) semi-vectorial finite difference method is used to calculate the difference between the nonreciprocal phase shifts of the two lowest-order modes and optimize the parameters. The proposed device may play an important role in integrated optical devices and optical communication systems

  15. LHC MD 652: Coupled-Bunch Instability with Smaller Emittance (all HOMs)

    CERN Document Server

    AUTHOR|(CDS)2081238; Timko, Helga; CERN. Geneva. ATS Department

    2017-01-01

    The aim of the MD was to measure the coupled-bunch stability from all HOM impedances, with a reduced longitudinal emittance in order to explore the HL-LHC conditions. The acceleration ramp was performed with the nominal beams of 2016, but a reduced target bunch length and RF voltage. With this reduced emittance, the beam remained close but above the single-bunch stability threshold. No coupled-bunch oscillations were observed, so we can conclude that the stability threshold for coupled-bunch instability is not lower than the single-bunch threshold. An interesting observation in the MD was the long-lasting injection oscillations, whose traces can still be seen at arrival to flat top; in agreement with observations in earlier MDs. The measurements took place between 28th October 20:00 and 29th October 05:10.

  16. Study and development of an input coupler for the future TESLA collider

    International Nuclear Information System (INIS)

    Dupery, C.

    1996-01-01

    The TESLA (TeV Superconducting Linear Accelerator) is operating with a high frequency cavity resonator input coupler. Some technical restraints (such as thermal, mechanical, electrical, vacuum, multipactor discharge phenomena) constrain the development of this coupler. In order to solve these problems, studies have been performed at the French Atomic Energy Commission (CEA) and are presented in this paper

  17. Low insertion loss SOI microring resonator integrated with nano-taper couplers

    DEFF Research Database (Denmark)

    Pu, Minhao; Frandsen, Lars Hagedorn; Ou, Haiyan

    2009-01-01

    We demonstrate a microring resonator working at TM mode integrated with nano-taper couplers with 3.6dB total insertion loss. The measured insertion loss of the nano-taper coupler was only 1.3dB for TM mode....

  18. Enhancement of entanglement in the nonlinear optical coupler by homodyne-mediated feedback

    Energy Technology Data Exchange (ETDEWEB)

    Ke Shasha [Department of Physics, Huazhong Normal University, Wuhan 430079 (China); Cheng Guiping [Department of Physics, Huazhong Normal University, Wuhan 430079 (China); Zhang Lihui [Department of Physics, Jianghan University, Wuhan 430056 (China); Li, Gao-xiang [Department of Physics, Huazhong Normal University, Wuhan 430079 (China)

    2007-07-28

    The enhancement of the intracavity entanglement of a nonlinear coupler via homodyne-mediated quantum feedback is investigated. It is found that the feedback can effectively enhance the squeezing, entanglement and purity of a two-mode field in the nonlinear coupler by appropriately choosing the quadrature angle at which the quantum feedback is introduced.

  19. All-optical switching in lithium niobate directional couplers with cascaded nonlinearity

    NARCIS (Netherlands)

    Schiek, R.; Baek, Y.; Krijnen, Gijsbertus J.M.; Stegeman, G.I.; Baumann, I.; Sohler, W.

    1996-01-01

    We report on intensity-dependent switching in lithium niobate directional couplers. Large nonlinear phase shifts that are due to cascading detune the coupling between the coupler branches, which makes all-optical switching possible. Depending on the input intensity, the output could be switched

  20. Detuning related coupler kick variation of a superconducting nine-cell 1.3 GHz cavity

    Science.gov (United States)

    Hellert, Thorsten; Dohlus, Martin

    2018-04-01

    Superconducting TESLA-type cavities are widely used to accelerate electrons in long bunch trains, such as in high repetition rate free electron lasers. The TESLA cavity is equipped with two higher order mode couplers and a fundamental power coupler (FPC), which break the axial symmetry of the cavity. The passing electrons therefore experience axially asymmetrical coupler kicks, which depend on the transverse beam position at the couplers and the rf phase. The resulting emittance dilution has been studied in detail in the literature. However, the kick induced by the FPC depends explicitly on the ratio of the forward to the backward traveling waves at the coupler, which has received little attention. The intention of this paper is to present the concept of discrete coupler kicks with a novel approach of separating the field disturbances related to the standing wave and a reflection dependent part. Particular attention is directed to the role of the penetration depth of the FPC antenna, which determines the loaded quality factor of the cavity. The developed beam transport model is compared to dedicated experiments at FLASH and European XFEL. Both the observed transverse coupling and detuning related coupler kick variations are in good agreement with the model. Finally, the expected trajectory variations due to coupler kick variations at European XFEL are investigated and results of numerical studies are presented.

  1. High efficiency grating couplers based on shared process with CMOS MOSFETs

    International Nuclear Information System (INIS)

    Qiu Chao; Sheng Zhen; Wu Ai-Min; Wang Xi; Zou Shi-Chang; Gan Fu-Wan; Li Le; Albert Pang

    2013-01-01

    Grating couplers are widely investigated as coupling interfaces between silicon-on-insulator waveguides and optical fibers. In this work, a high-efficiency and complementary metal—oxide—semiconductor (CMOS) process compatible grating coupler is proposed. The poly-Si layer used as a gate in the CMOS metal—oxide—semiconductor field effect transistor (MOSFET) is combined with a normal fully etched grating coupler, which greatly enhances its coupling efficiency. With optimal structure parameters, a coupling efficiency can reach as high as ∼ 70% at a wavelength of 1550 nm as indicated by simulation. From the angle of fabrication, all masks and etching steps are shared between MOSFETs and grating couplers, thereby making the high performance grating couplers easily integrated with CMOS circuits. Fabrication errors such as alignment shift are also simulated, showing that the device is quite tolerant in fabrication. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  2. Model coupler for coupling of atmospheric, oceanic, and terrestrial models

    International Nuclear Information System (INIS)

    Nagai, Haruyasu; Kobayashi, Takuya; Tsuduki, Katsunori; Kim, Keyong-Ok

    2007-02-01

    A numerical simulation system SPEEDI-MP, which is applicable for various environmental studies, consists of dynamical models and material transport models for the atmospheric, terrestrial, and oceanic environments, meteorological and geographical databases for model inputs, and system utilities for file management, visualization, analysis, etc., using graphical user interfaces (GUIs). As a numerical simulation tool, a model coupling program (model coupler) has been developed. It controls parallel calculations of several models and data exchanges among them to realize the dynamical coupling of the models. It is applicable for any models with three-dimensional structured grid system, which is used by most environmental and hydrodynamic models. A coupled model system for water circulation has been constructed with atmosphere, ocean, wave, hydrology, and land-surface models using the model coupler. Performance tests of the coupled model system for water circulation were also carried out for the flood event at Saudi Arabia in January 2005 and the storm surge case by the hurricane KATRINA in August 2005. (author)

  3. Preventing distortion of quick couplers of hoses of central pipe lines--a cheap and simple method.

    Directory of Open Access Journals (Sweden)

    Kamath S

    1995-01-01

    Full Text Available A cheap and practical approach of steel chains attached to the station outlet quick couplers helps in maintaining the shape of the quick couplers and ensures their effective functioning over a long period of time and avoids mishap of connection due to damage of these couplers.

  4. Finite element analysis and frequency shift studies for the bridge coupler of the coupled cavity linear accelerator of the spallation neutron source.

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z. (Zukun)

    2001-01-01

    The Spallation Neutron Source (SNS) is an accelerator-based neutron scattering research facility. The linear accelerator (linac) is the principal accelerating structure and divided into a room-temperature linac and a superconducting linac. The normal conducting linac system that consists of a Drift Tube Linac (DTL) and a Coupled Cavity Linac (CCL) is to be built by Los Alamos National Laboratory. The CCL structure is 55.36-meters long. It accelerates H- beam from 86.8 Mev to 185.6 Mev at operating frequency of 805 MHz. This side coupled cavity structure has 8 cells per segment, 12 segments and 11 bridge couplers per module, and 4 modules total. A 5-MW klystron powers each module. The number 3 and number 9 bridge coupler of each module are connected to the 5-MW RF power supply. The bridge coupler with length of 2.5 {beta}{gamma} is a three-cell structure and located between the segments and allows power flow through the module. The center cell of each bridge coupler is excited during normal operation. To obtain a uniform electromagnetic filed and meet the resonant frequency shift, the RF induced heat must be removed. Thus, the thermal deformation and frequency shift studies are performed via numerical simulations in order to have an appropriate cooling design and predict the frequency shift under operation. The center cell of the bridge coupler also contains a large 4-inch slug tuner and a tuning post that used to provide bulk frequency adjustment and field intensity adjustment, so that produce the proper total field distribution in the module assembly.

  5. Fully-etched apodized fiber-to-chip grating coupler on the SOI platform with -0.78 dB coupling efficiency using photonic crystals and bonded Al mirror

    DEFF Research Database (Denmark)

    Ding, Yunhong; Ou, Haiyan; Peucheret, Christophe

    2014-01-01

    We design and fabricate an ultra-high coupling efficiency fully-etched apodized grating coupler on the SOI platform using photonic crystals and bonded aluminum mirror. Ultra-high coupling efficiency of -0.78 dB with a 3 dB bandwidth of 74 nm are demonstrated.......We design and fabricate an ultra-high coupling efficiency fully-etched apodized grating coupler on the SOI platform using photonic crystals and bonded aluminum mirror. Ultra-high coupling efficiency of -0.78 dB with a 3 dB bandwidth of 74 nm are demonstrated....

  6. Silicon nitride tri-layer vertical Y-junction and 3D couplers with arbitrary splitting ratio for photonic integrated circuits.

    Science.gov (United States)

    Shang, Kuanping; Pathak, Shibnath; Liu, Guangyao; Feng, Shaoqi; Li, Siwei; Lai, Weicheng; Yoo, S J B

    2017-05-01

    We designed and demonstrated a tri-layer Si3N4/SiO2 photonic integrated circuit capable of vertical interlayer coupling with arbitrary splitting ratios. Based on this multilayer photonic integrated circuit platform with each layer thicknesses of 150 nm, 50 nm, and 150 nm, we designed and simulated the vertical Y-junctions and 3D couplers with arbitrary power splitting ratios between 1:10 and 10:1 and with negligible(< -50 dB) reflection. Based on the design, we fabricated and demonstrated tri-layer vertical Y-junctions with the splitting ratios of 1:1 and 3:2 with excess optical losses of 0.230 dB. Further, we fabricated and demonstrated the 1 × 3 3D couplers with the splitting ratio of 1:1:4 for symmetric structures and variable splitting ratio for asymmetric structures.

  7. A Novel Ku-Band/Ka-Band and Ka-Band/E-Band Multimode Waveguide Couplers for Power Measurement of Traveling-Wave Tube Amplifier Harmonic Frequencies

    Science.gov (United States)

    Wintucky, Edwin G.; Simons, Rainee N.

    2015-01-01

    This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler, fabricated from two dissimilar frequency band waveguides, is capable of isolating power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT) amplifier. Test results from proof-of-concept demonstrations are presented for a Ku-band/Ka-band MDC and a Ka-band/E-band MDC. In addition to power measurements at harmonic frequencies, a potential application of the MDC is in the design of a satellite borne beacon source for atmospheric propagation studies at millimeter-wave (mm-wave) frequencies (Ka-band and E-band).

  8. On-chip grating coupler array on the SOI platform for fan-in/fan-out of multi-core fibers with low insertion loss and crosstalk

    DEFF Research Database (Denmark)

    Ding, Yunhong; Ye, Feihong; Peucheret, Christophe

    2014-01-01

    We design and fabricate a compact multi-core fiber fan-in/fan-out using a fully-etched grating coupler array on the SOI platform. Lowest coupling loss of 6.8 dB with 3 dB bandwidth of 48 nm and crosstalk lower than ×32 dB are demonstrated.......We design and fabricate a compact multi-core fiber fan-in/fan-out using a fully-etched grating coupler array on the SOI platform. Lowest coupling loss of 6.8 dB with 3 dB bandwidth of 48 nm and crosstalk lower than ×32 dB are demonstrated....

  9. Acoustic coupler for acquisition of coronary artery murmurs

    DEFF Research Database (Denmark)

    Zimmermann, Niels Henrik; Schmidt, Samuel; Hansen, John

    2011-01-01

    in a clinical trial including 463 patients referred for elective coronary angiography. The preliminary results show, that it was possible to record heart sound in the diastolic period with a sound pressure level approximately 30 dB above the noise floor of the microphone and recording system in the frequency...... of the coupler, while the low frequency behavior was determined by the properties of the microphone, electronic circuits and inadvertent leakages in the acoustical coupling. The requirement for the microphone and pr-amplifier was a low inherent noise level. The setup was used for collection of heart sounds...... range from 200-700 Hz. The capability of the sensor to record diastolic heart sound in the relevant frequency range indicates that the sensor is suitable for recording of coronary murmurs....

  10. Baking Arithmetic and Error Analyses for PEFP Fundamental Power Couplers

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Liping; An, Sun; Tang, Yazhe; Cho, Yong Sub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-05-15

    The Proton Engineering Frontier Project (PEFP) is considering developing and using SRF technology to accelerate a proton beam at 700 MHz in its present project and its extended project (PEP). The first section of the PEFP SRF linac (SCL) is composed of low-beta cryomodules. Each cryomodule has three 5-cell cavities and each cavity has one fundamental power coupler (FPC). Before the high power RF processing, each FPC needs to be baked out for 24 hours at 200 degrees Celsius ( .deg. C). The whole control system is described in reference, in this system, the temperature in the baking-box need to be changed according to three straight lines with different slope. This paper described how we can make the temperature of the baking-box changed according to the required values.

  11. Baking Arithmetic and Error Analyses for PEFP Fundamental Power Couplers

    International Nuclear Information System (INIS)

    Zhang, Liping; An, Sun; Tang, Yazhe; Cho, Yong Sub

    2009-01-01

    The Proton Engineering Frontier Project (PEFP) is considering developing and using SRF technology to accelerate a proton beam at 700 MHz in its present project and its extended project (PEP). The first section of the PEFP SRF linac (SCL) is composed of low-beta cryomodules. Each cryomodule has three 5-cell cavities and each cavity has one fundamental power coupler (FPC). Before the high power RF processing, each FPC needs to be baked out for 24 hours at 200 degrees Celsius ( .deg. C). The whole control system is described in reference, in this system, the temperature in the baking-box need to be changed according to three straight lines with different slope. This paper described how we can make the temperature of the baking-box changed according to the required values

  12. Development of photonic-crystal-fiber-based optical coupler with a broad operating wavelength range of 800 nm

    International Nuclear Information System (INIS)

    Yoon, Min-Seok; Kwon, Oh-Jang; Kim, Hyun-Joo; Chu, Su-Ho; Kim, Gil-Hwan; Lee, Sang-Bae; Han, Young-Geun

    2010-01-01

    We developed a broadband optical coupler based on a photonic crystal fiber (PCF), which is very useful for applications to optical coherence tomography (OCT). The PCF-based coupler is fabricated by using a fused biconical tapering (FBT) method. The PCF has six hexagonally-stacked layers of air holes. The PCF-based coupler has a nearly-flat 50/50 coupling ratio in a broad bandwidth range of 800 nm, which is much wider than that previously reported for a PCF-based coupler and a singlemode-fiber-based coupler. The bandwidth and the bandedge wavelength of the broadband coupler are controlled by changing the elongation length. The fabricated broadband optical coupler has great potential for realizing a broadband interferogram with a high resolution in an OCT system.

  13. Theoretical and experimental analysis of a linear accelerator endowed with single feed coupler with movable short-circuit

    International Nuclear Information System (INIS)

    Forno, Massimo Dal; Craievich, Paolo; Penco, Giuseppe; Vescovo, Roberto

    2013-01-01

    The front-end injection systems of the FERMI@Elettra linac produce high brightness electron beams that define the performance of the Free Electron Laser. The photoinjector mainly consists of the radiofrequency (rf) gun and of two S-band rf structures which accelerate the beam. Accelerating structures endowed with a single feed coupler cause deflection and degradation of the electron beam properties, due to the asymmetry of the electromagnetic field. In this paper, a new type of single feed structure with movable short-circuit is proposed. It has the advantage of having only one waveguide input, but we propose a novel design where the dipolar component is reduced. Moreover, the racetrack geometry allows to reduce the quadrupolar component. This paper presents the microwave design and the analysis of the particle motion inside the linac. A prototype has been machined at the Elettra facility to verify the new coupler design and the rf field has been measured by adopting the bead-pull method. The results are here presented, showing good agreement with the expectations

  14. Theoretical and experimental analysis of a linear accelerator endowed with single feed coupler with movable short-circuit.

    Science.gov (United States)

    Dal Forno, Massimo; Craievich, Paolo; Penco, Giuseppe; Vescovo, Roberto

    2013-11-01

    The front-end injection systems of the FERMI@Elettra linac produce high brightness electron beams that define the performance of the Free Electron Laser. The photoinjector mainly consists of the radiofrequency (rf) gun and of two S-band rf structures which accelerate the beam. Accelerating structures endowed with a single feed coupler cause deflection and degradation of the electron beam properties, due to the asymmetry of the electromagnetic field. In this paper, a new type of single feed structure with movable short-circuit is proposed. It has the advantage of having only one waveguide input, but we propose a novel design where the dipolar component is reduced. Moreover, the racetrack geometry allows to reduce the quadrupolar component. This paper presents the microwave design and the analysis of the particle motion inside the linac. A prototype has been machined at the Elettra facility to verify the new coupler design and the rf field has been measured by adopting the bead-pull method. The results are here presented, showing good agreement with the expectations.

  15. Raman probes based on optically-poled double-clad fiber and coupler

    DEFF Research Database (Denmark)

    Brunetti, Anna Chiara; Margulis, Walter; Rottwitt, Karsten

    2012-01-01

    of a sample of dimethyl sulfoxide (DMSO), when illuminating the waveguide with 1064nm laser light. The Raman signal is collected in the inner cladding, from which it is retrieved with either a bulk dichroic mirror or a double-clad fiber coupler. The coupler allows for a substantial reduction of the fiber......Two fiber Raman probes are presented, one based on an optically-poled double-clad fiber and the second based on an optically-poled double-clad fiber coupler respectively. Optical poling of the core of the fiber allows for the generation of enough 532nm light to perform Raman spectroscopy...

  16. HF power couplers for pulsed superconducting cavity resonators; Coupleurs de puissance HF pour cavites supraconductrices en mode pulse

    Energy Technology Data Exchange (ETDEWEB)

    Jenhani, Hassen [Laboratoire de l' Accelerateur Lineaire, IN2P3-CNRS et Universite de Paris-Sud, BP 34, F-91898 Orsay Cedex (France)

    2006-11-15

    Recent years have seen an impressive improvement in the accelerating gradients obtained in superconducting cavities. Consequently, such cavities have become attractive candidates for large superconducting linear accelerator projects such as the European XFEL and the International Linear Collider (ILC). As a result, there is a strong interest in reducing RF conditioning time and improving the performance of the input power couplers for these cavities. The so-called TTF-III input power coupler, adopted for the XFEL superconducting RF cavities are complex components. In order to better understand the behavior of this component we have performed a series of experiments on a number of such couplers. Initially, we developed a fully automated RF high power test stand for coupler conditioning procedure. Following this, we performed a series of coupler conditioning tests. This has allowed the study of the coupler behavior during processing. A number of experiments were carried out to evaluate the in-situ baking effect on the conditioning time. Some of the conditioned couplers were sent to DESY in order to be tested on 9-cells TESLA cavities under cryogenic conditions. These tests have shown that the couplers in no way limit the cavity performance, even up to gradients of 35 MV/m. The main objective of our coupler studies was the reduction of their conditioning time, which represents one of the most important criteria in the choice of coupler for high energy linacs. Excellent progress in reducing the conditioning time has been demonstrated by making appropriate modifications to the conditioning procedure. Furthermore, special attention was paid to electron generation processes in the couplers, via multipacting. Simulations of this process were made on both the TTF-III coupler and on a new coupler prototype, TTF-V. Experiments aimed at suppressing multipacting were also successfully achieved by using a DC bias on the inner conductor of the co-axial coupler. (author)

  17. [Homöopathisch-phytotherapeutische Behandlung des Reizdarmsyndroms mit Magen-Darm-Entoxin N®: Eine Anwendungsbeobachtung].

    Science.gov (United States)

    Märtens, Diane; Range, Natasha; Günnewich, Nils; Gruber, Nicola; Schmidt, Stefan

    Hintergrund: In dieser Anwendungsbeobachtung wird zum ersten Mal die Behandlung des Reizdarmsyndroms (RDS) mit einem homöopathisch-phytotherapeutischen Komplexpräparat beschrieben. Methodik: Ziel der 6-wöchigen Therapie mit dem Magen-Darm-Entoxin N® war die Reduzierung der RDS-Symptomatik sowie die Verbesserung der Lebensqualität. Zielkriterien waren die Veränderungen in der Irritable Bowel Syndrome - Severity Scoring System (IBS-SSS) und der Irritable Bowel Syndrome - Quality-of-Life Scale (IBS-QoL). Die Patient/innen (N = 41; Alter 44,0 ± 15,74 Jahre) wurden zu gleichen Teilen in einer Hausarztpraxis (N = 20) und einer Heilpraktikerpraxis (N = 21) rekrutiert. Ergebnisse: Der IBS-QoL-Score verringerte sich signifikant (prä: 35,9 ± 16,3; post: 20,1 ± 13,4; t = 8,504; p mit einer Effektstärke von d = 1,24. Die Neben- und Wechselwirkungen waren minimal und signifikante Unterschiede zwischen beiden Praxen wurden nicht gefunden. Schlussfolgerungen: Magen-Darm-Entoxin N® ist eine sichere und sinnvolle Therapieoption bei der Behandlung des RDS. Allerdings sollten randomisierte kontrollierte Studien folgen, um die Spezifizität der Ergebnisse dieser Anwendungsbeobachtung zu stützen. © 2017 S. Karger GmbH, Freiburg.

  18. SRF cavity alignment detection method using beam-induced HOM with curved beam orbit

    Science.gov (United States)

    Hattori, Ayaka; Hayano, Hitoshi

    2017-09-01

    We have developed a method to obtain mechanical centers of nine cell superconducting radio frequency (SRF) cavities from localized dipole modes, that is one of the higher order modes (HOM) induced by low-energy beams. It is to be noted that low-energy beams, which are used as alignment probes, are easy to bend in fringe fields of accelerator cavities. The estimation of the beam passing orbit is important because only information about the beam positions measured by beam position monitors outside the cavities is available. In this case, the alignment information about the cavities can be obtained by optimizing the parameters of the acceleration components over the beam orbit simulation to consistently represent the position of the beam position monitors measured at every beam sweep. We discuss details of the orbit estimation method, and estimate the mechanical center of the localized modes through experiments performed at the STF accelerator. The mechanical center is determined as (x , y) =(0 . 44 ± 0 . 56 mm , - 1 . 95 ± 0 . 40 mm) . We also discuss the error and the applicable range of this method.

  19. Un problema de lengua homérica: la desinencia -φι

    Directory of Open Access Journals (Sweden)

    Purificación Nieto Hernández

    1987-12-01

    Full Text Available The author of this paper tries to show the historical evolution of -φι in Mycenaean and Homeric Greek. In spite of the apparently considerable divergence between mic. -pi and hom. -φι, the function of the -φι case in Mycenaean —instr. locat.— is also the primary function of -φι in the Epic language. Moreover, in the language of Homer -φι always functions in a way closer to the dative than to the genitive. The traditionally adduced examples of -φι as a genitive in some passages of the Iliad and the Odyssey can be interpreted otherwise. The evolution of -φι that we can test in the Homeric works, was not a merely artificial one. On the contrary, it bears a close relation with a series of morphophonological developments which took place in the spoken language during the shift from the second to the first millennium B.C. As a result from that, -φι disappears from the normal spoken language very early, but the Homeric bards maintain this archaism for metrical and poetical reasons.

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

    Science.gov (United States)

    Guan, Xiaotong; Fu, Wenjie; Yan, Yang

    2018-02-01

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

  1. Ultra-low-loss inverted taper coupler for silicon-on-insulator ridge waveguide

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    An ultra-low-loss coupler for interfacing a silicon-on-insulator ridge waveguide and a single-mode fiber in both polarizations is presented. The inverted taper coupler, embedded in a polymer waveguide, is optimized for both the transverse-magnetic and transverse-electric modes through tapering...... the width of the silicon-on-insulator waveguide from 450 nm down to less than 15 nm applying a thermal oxidation process. Two inverted taper couplers are integrated with a 3-mm long silicon-on-insulator ridge waveguide in the fabricated sample. The measured coupling losses of the inverted taper coupler...... for transverse-magnetic and transverse-electric modes are ~0.36 dB and ~0.66 dB per connection, respectively....

  2. Fiber pigtailed thin wall capillary coupler for excitation of microsphere WGM resonator.

    Science.gov (United States)

    Wang, Hanzheng; Lan, Xinwei; Huang, Jie; Yuan, Lei; Kim, Cheol-Woon; Xiao, Hai

    2013-07-01

    In this paper, we demonstrate a fiber pigtailed thin wall capillary coupler for excitation of Whispering Gallery Modes (WGMs) of microsphere resonators. The coupler is made by fusion-splicing an optical fiber with a capillary tube and consequently etching the capillary wall to a thickness of a few microns. Light is coupled through the peripheral contact between inserted microsphere and the etched capillary wall. The coupling efficiency as a function of the wall thickness was studied experimentally. WGM resonance with a Q-factor of 1.14 × 10(4) was observed using a borosilicate glass microsphere with a diameter of 71 μm. The coupler operates in the reflection mode and provides a robust mechanical support to the microsphere resonator. It is expected that the new coupler may find broad applications in sensors, optical filters and lasers.

  3. Venous coupler use for free-flap breast reconstructions: specific analyses of TMG and DIEP flaps.

    Science.gov (United States)

    Bodin, Frédéric; Brunetti, Stefania; Dissaux, Caroline; Erik, A Sauleau; Facca, Sybille; Bruant-Rodier, Catherine; Liverneaux, Philippe

    2015-05-01

    The purpose of this report was to present the results of comparisons of anastomotic data and flap complications in the use of venous coupler in breast reconstruction with the transverse musculocutaneous gracilis (TMG) flap and the deep inferior epigastric perforator (DIEP) flap. Over a three-year period, 95 patients suffering from breast cancer were treated with mastectomy and breast reconstruction using free flaps. We performed 121 mechanical venous anastomoses for 105 flap procedures (80 DIEP and 25 TMG). The coupler size, anastomotic duration, number of anastomoses and postoperative complications were assessed for the entire series. The coupling device was perfectly suitable for all end-to-end anastomoses between the vein(s) of the flap and the internal mammary vein(s). No venous thrombosis occurred. The mean anastomotic time did not significantly differ between the DIEP (330 seconds) and TMG flap procedures (352 seconds) (P = 0.069). Additionally, there were no differences in coupling time observed following a comparison of seven coupler sizes (P = 0.066). The mean coupler size used during the TMG flap procedure was smaller than that used with the DIEP (2.4 mm versus 2.8 mm) (P TMG flap (28%) than with the DIEP flap (11%). The coupler size used was smaller for the TMG procedure and when double venous anastomosis was performed. Additionally, anastomotic time was not affected by the flap type or coupler size used or by anastomosis number. © 2014 Wiley Periodicals, Inc.

  4. Wakefield and RF Kicks Due to Coupler Asymmetry in TESLA-Type Accelerating Cavities

    International Nuclear Information System (INIS)

    Bane, K

    2008-01-01

    In a future linear collider, such as the International Linear Collider (ILC), trains of high current, low emittance bunches will be accelerated in a linac before colliding at the interaction point. Asymmetries in the accelerating cavities of the linac will generate fields that will kick the beam transversely and degrade the beam emittance and thus the collider performance. In the main linac of the ILC, which is filled with TESLA-type superconducting cavities, it is the fundamental (FM) and higher mode (HM) couplers that are asymmetric and thus the source of such kicks. The kicks are of two types: one, due to (the asymmetry in) the fundamental RF fields and the other, due to transverse wakefields that are generated by the beam even when it is on axis. In this report we calculate the strength of these kicks and estimate their effect on the ILC beam. The TESLA cavity comprises nine cells, one HM coupler in the upstream end, and one (identical, though rotated) HM coupler and one FM coupler in the downstream end (for their shapes and location see Figs. 1, 2) [1]. The cavity is 1.1 m long, the iris radius 35 mm, and the coupler beam pipe radius 39 mm. Note that the couplers reach closer to the axis than the irises, down to a distance of 30 mm

  5. Simulation and optimization of a polymer directional coupler electro-optic switch with push pull electrodes

    Science.gov (United States)

    Zheng, Chuan-Tao; Ma, Chun-Sheng; Yan, Xin; Wang, Xian-Yin; Zhang, Da-Ming

    2008-07-01

    Structural model and design technique are proposed for a polymer directional coupler electro-optic switch with rib waveguides and push-pull electrodes, of which the electric field distribution is analyzed by the conformal transforming method and image method. In order to get the minimum mode loss and the minimum switching voltage, the parameters of the waveguide and electrode are optimized, such as the core with, core thickness, buffer layer between the core and the electrode, coupling gap between the waveguides, electrode thickness, electrode width and electrode gap. Switching Characteristics are analyzed, which include the output power, insertion loss, and crosstalk. To realize normal switching function, the fabrication error, spectrum shift, and coupling loss between a single mode fiber (SMF) and the waveguide are discussed. Simulation results show that the coupling length is 3082 μm, push-pull switching voltage is 2.14 V, insertion loss is less than 1.17 dB, and crosstalk is less than -30 dB for the designed device.

  6. Polymer waveguide couplers based on metal nanoparticle–polymer nanocomposites

    International Nuclear Information System (INIS)

    Signoretto, M; Suárez, I; Chirvony, V S; Martínez-Pastor, J; Abargues, R; Rodríguez-Cantó, P J

    2015-01-01

    In this work Au nanoparticles (AuNPs) are incorporated into poly(methyl methacrylate) (PMMA) waveguides to develop optical couplers that are compatible with planar organic polymer photonics. A method for growing AuNPs (of 10 to 100 nm in size) inside the commercially available Novolak resist is proposed with the intention of tuning the plasmon resonance and the absorption/scattering efficiencies inside the patterned structures. The refractive index of the MNP–Novolak nanocomposite (MNPs: noble metal nanoparticles) is carefully analysed both experimentally and numerically in order to find the appropriate fabrication conditions (filling factor and growth time) to optimize the scattering cross section at a desired wavelength. Then the nanocomposite is patterned inside a PMMA waveguide to exploit its scattering properties to couple and guide a normal incident laser light beam along the polymer. In this way, light coupling is experimentally demonstrated in a broad wavelength range (404–780 nm). Due to the elliptical shape of the MNPs the nanocomposite demonstrates a birefringence, which enhances the coupling to the TE mode up to efficiencies of around 1%. (paper)

  7. Geochemistry and uranium content of phosphorites used in fertilizer industry - Homs in comparison with mines raw phosphorites

    International Nuclear Information System (INIS)

    Kudsi, Yahia; Abbas, Mahmoud

    1992-03-01

    geochemical characteristics of phosphates used in fertilizer industry at Homs were studied. 28 monthly averaged samples from Palmyrides mining areas were mineralogically and chemically analyzed for P 2 O 5 , CaO and U. Specifically, U content was determined by fluorometry, x-ray fluorescence and γ spectrometry. Results show that the phosphates under study are similar to that exploited at Charquieh mines. U shows a positive correlation with P 2 O 5 and not with CaO. Statistical analyses indicate that fluorometry is more accurate than x-ray fluorescence and γ spectrometry. (author). 14 refs., 23 figs., 5 tabs

  8. Asymmetric focusing study from twin input power couplers using realistic rf cavity field maps

    Directory of Open Access Journals (Sweden)

    Colwyn Gulliford

    2011-03-01

    Full Text Available Advanced simulation codes now exist that can self-consistently solve Maxwell’s equations for the combined system of an rf cavity and a beam bunch. While these simulations are important for a complete understanding of the beam dynamics in rf cavities, they require significant time and computing power. These techniques are therefore not readily included in real time simulations useful to the beam physicist during beam operations. Thus, there exists a need for a simplified algorithm which simulates realistic cavity fields significantly faster than self-consistent codes, while still incorporating enough of the necessary physics to ensure accurate beam dynamics computation. To this end, we establish a procedure for producing realistic field maps using lossless cavity eigenmode field solvers. This algorithm incorporates all relevant cavity design and operating parameters, including beam loading from a nonrelativistic beam. The algorithm is then used to investigate the asymmetric quadrupolelike focusing produced by the input couplers of the Cornell ERL injector cavity for a variety of beam and operating parameters.

  9. Laser tissue coagulation and concurrent optical coherence tomography through a double-clad fiber coupler

    Science.gov (United States)

    Beaudette, Kathy; Baac, Hyoung Won; Madore, Wendy-Julie; Villiger, Martin; Godbout, Nicolas; Bouma, Brett E.; Boudoux, Caroline

    2015-01-01

    Double-clad fiber (DCF) is herein used in conjunction with a double-clad fiber coupler (DCFC) to enable simultaneous and co-registered optical coherence tomography (OCT) and laser tissue coagulation. The DCF allows a single channel fiber-optic probe to be shared: i.e. the core propagating the OCT signal while the inner cladding delivers the coagulation laser light. We herein present a novel DCFC designed and built to combine both signals within a DCF (>90% of single-mode transmission; >65% multimode coupling). Potential OCT imaging degradation mechanisms are also investigated and solutions to mitigate them are presented. The combined DCFC-based system was used to induce coagulation of an ex vivo swine esophagus allowing a real-time assessment of thermal dynamic processes. We therefore demonstrate a DCFC-based system combining OCT imaging with laser coagulation through a single fiber, thus enabling both modalities to be performed simultaneously and in a co-registered manner. Such a system enables endoscopic image-guided laser marking of superficial epithelial tissues or laser thermal therapy of epithelial lesions in pathologies such as Barrett’s esophagus. PMID:25909013

  10. Capturing reflected cladding modes from a fiber Bragg grating with a double-clad fiber coupler.

    Science.gov (United States)

    Baiad, Mohamad Diaa; Gagné, Mathieu; Lemire-Renaud, Simon; De Montigny, Etienne; Madore, Wendy-Julie; Godbout, Nicolas; Boudoux, Caroline; Kashyap, Raman

    2013-03-25

    We present a novel measurement scheme using a double-clad fiber coupler (DCFC) and a fiber Bragg grating (FBG) to resolve cladding modes. Direct measurement of the optical spectra and power in the cladding modes is obtained through the use of a specially designed DCFC spliced to a highly reflective FBG written into slightly etched standard photosensitive single mode fiber to match the inner cladding diameter of the DCFC. The DCFC is made by tapering and fusing two double-clad fibers (DCF) together. The device is capable of capturing backward propagating low and high order cladding modes simply and efficiently. Also, we demonstrate the capability of such a device to measure the surrounding refractive index (SRI) with an extremely high sensitivity of 69.769 ± 0.035 μW/RIU and a resolution of 1.433 × 10(-5) ± 8 × 10(-9) RIU between 1.37 and 1.45 RIU. The device provides a large SRI operating range from 1.30 to 1.45 RIU with sufficient discrimination for all individual captured cladding modes. The proposed scheme can be adapted to many different types of bend, temperature, refractive index and other evanescent wave based sensors.

  11. Study of a power coupler for superconducting RF cavities used in high intensity proton accelerator; Etude et developpement d'un coupleur de puissance pour les cavites supraconductrices destinees aux accelerateurs de protons de haute intensite

    Energy Technology Data Exchange (ETDEWEB)

    Souli, M

    2007-07-15

    The coaxial power coupler needed for superconducting RF cavities used in the high energy section of the EUROTRANS driver should transmit 150 kW (CW operation) RF power to the protons beam. The calculated RF and dielectric losses in the power coupler (inner and outer conductor, RF window) are relatively high. Consequently, it is necessary to design very carefully the cooling circuits in order to remove the generated heat and to ensure stable and reliable operating conditions for the coupler cavity system. After calculating all type of losses in the power coupler, we have designed and validated the inner conductor cooling circuit using numerical simulations results. We have also designed and optimized the outer conductor cooling circuit by establishing its hydraulic and thermal characteristics. Next, an experiment dedicated to study the thermal interaction between the power coupler and the cavity was successfully performed at CRYOHLAB test facility. The critical heat load Qc for which a strong degradation of the cavity RF performance was measured leading to Q{sub c} in the range 3 W-5 W. The measured heat load will be considered as an upper limit of the residual heat flux at the outer conductor cold extremity. A dedicated test facility was developed and successfully operated for measuring the performance of the outer conductor heat exchanger using supercritical helium as coolant. The test cell used reproduces the realistic thermal boundary conditions of the power coupler mounted on the cavity in the cryo-module. The first experimental results have confirmed the excellent performance of the tested heat exchanger. The maximum residual heat flux measured was 60 mW for a 127 W thermal load. As the RF losses in the coupler are proportional to the incident RF power, we can deduce that the outer conductor heat exchanger performance is continued up to 800 kW RF power. Heat exchanger thermal conductance has been identified using a 2D axisymmetric thermal model by comparing

  12. A study of polaritonic transparency in couplers made from excitonic materials

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Mahi R.; Racknor, Chris [Department of Physics and Astronomy, Western University, London, Ontario N6A 3K7 (Canada)

    2015-03-14

    We have studied light matter interaction in quantum dot and exciton-polaritonic coupler hybrid systems. The coupler is made by embedding two slabs of an excitonic material (CdS) into a host excitonic material (ZnO). An ensemble of non-interacting quantum dots is doped in the coupler. The bound exciton polariton states are calculated in the coupler using the transfer matrix method in the presence of the coupling between the external light (photons) and excitons. These bound exciton-polaritons interact with the excitons present in the quantum dots and the coupler is acting as a reservoir. The Schrödinger equation method has been used to calculate the absorption coefficient in quantum dots. It is found that when the distance between two slabs (CdS) is greater than decay length of evanescent waves the absorption spectrum has two peaks and one minimum. The minimum corresponds to a transparent state in the system. However, when the distance between the slabs is smaller than the decay length of evanescent waves, the absorption spectra has three peaks and two transparent states. In other words, one transparent state can be switched to two transparent states when the distance between the two layers is modified. This could be achieved by applying stress and strain fields. It is also found that transparent states can be switched on and off by applying an external control laser field.

  13. Magnetic field sensor based on cascaded microfiber coupler with magnetic fluid

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Lianmin; Su, Delong; Wang, Zhaofang [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China); Pu, Shengli, E-mail: shlpu@usst.edu.cn [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China); Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093 (China); Zeng, Xianglong [The Key Lab of Specialty Fiber Optics and Optical Access Network, Shanghai University, Shanghai 200072 (China); Lahoubi, Mahieddine [Laboratory L.P.S., Department of Physics, Faculty of Sciences, Badji-Mokhtar Annaba University, Annaba 23000 (Algeria)

    2016-09-07

    A kind of magnetic field sensor based on cascaded microfiber coupler with magnetic fluid is proposed and experimentally demonstrated. The magnetic fluid is utilized as the cladding of the fused regions of the cascaded microfiber coupler. As the interference valley wavelength of the sensing structure is sensitive to the ambient variation, considering the magnetic-field-dependent refractive index of magnetic fluid, the proposed structure is employed for magnetic field sensing. The effective coupling length for each coupling region of the as-fabricated cascaded microfiber coupler is 6031 μm. The achieved sensitivity is 125 pm/Oe, which is about three times larger than that of the previously similar structure based on the single microfiber coupler. Experimental results indicate that the sensing sensitivity can be easily improved by increasing the effective coupling length or cascading more microfiber couplers. The proposed magnetic field sensor is attractive due to its low cost, immunity to electromagnetic interference, as well as high sensitivity, which also has the potentials in other tunable all-fiber photonic devices, such as filter.

  14. El Abencerraje como problema heroico: una lectura según modelos homéricos

    Directory of Open Access Journals (Sweden)

    Terradas, José Carlos

    2012-06-01

    Full Text Available Despite the deep epic and mythological relations that the Abencerraje presents and the knowledge in this area of the alleged author, Antonio de Villegas, we still lack of studies connecting the work with Homeric patterns. This paper represents an effort to illustrate how the quest for beauty that initially was understood as the retrieving of the beloved lady, ultimately becomes an ethical quest that favors heroic asceticism. We will critically review about the characters of Narváez and Abindarráez, their presumed differences, their commitment to attain public esteem, their detachment from sensual pleasures in order to complete a chivalrous and warlike paradigm. Finally, we stop at the cosmology that the work presents in order to explain an oppressive religious system masquerading as Christianity, but that basically contains much of the Greek concept of the envy of the gods.A pesar de las profundas relaciones épicas y mitológicas que presenta el Abencerraje y el conocimiento en esta materia del presunto autor, Antonio de Villegas, aún carecemos de estudios que conecten la obra con los modelos homéricos. Este artículo representa un esfuerzo por ejemplificar cómo la búsqueda de la belleza que en un principio se entendía como recuperación de la amada, se transforma en una búsqueda ética que propicia la ascesis heroica. Haremos una revisión crítica acerca de Nárvaez y Abindarráez, de sus supuestas diferencias, del compromiso de ambos con el logro de la admiración pública, de su alejamiento de los placeres sensuales para consumar un paradigma caballeresco y guerrero compartido. Finalmente, nos detendremos en la cosmología que presenta la obra con el objeto de explicar un sistema religioso opresivo que se disfraza de cristianismo, pero que en el fondo contiene mucho del concepto griego de la envidia de los dioses.

  15. New clic-g structure design

    CERN Document Server

    AUTHOR|(CDS)2082335

    2016-01-01

    The baseline design of the Compact Linear Collider main linac accelerating structure is called ‘CLIC-G’. It is described in the CLIC Conceptual Design Report (CDR) [1]. As shown in Fig. 1, a regular cell of the structure has four waveguides to damp unwanted high-order-modes (HOMs). These waveguides are dimensioned to cut off the fundamental working frequency in order to prevent the degradation of the fundamental mode Q-factor. The cell geometry and HOM damping loads had been extensively optimized in order to maximize the RF-to-beam efficiency, to minimize the cost, and to meet the beam dynamics and the high gradient RF constraints [2

  16. Contribution to the study of accelerating structure for electrons and respective radiofrequency couplers

    International Nuclear Information System (INIS)

    Franco, M.A.R.

    1991-01-01

    In this work, the experimental results pertaining to the construction and evaluation of a constant gradient accelerating structure and of the radiofrequency couplers are presented. The theoretical methods to determine the initial dimensions of the iris-loaded accelerating structure are presented. The final dimensions have been experimentally determined utilizing four three-cavity sections representing the 4 sup(th), 12 sup(th), 20 sup(th) and 27 sup(th) cavities of the final structure. The diameters of the cavities were corrected for variations of temperature, pressure and humidity. A v sub(p) = c, constant gradient, twelve-cavity prototype of the accelerating structure have been constructed and its principal parameters were experimentally determined according to methods also described in this work. Two prototypes of door-knob type radiofrequency couplers have been constructed and experimental procedures to match and tune the couplers and the accelerating structure were implemented. (author)

  17. All-optical switching using a new photonic crystal directional coupler

    Directory of Open Access Journals (Sweden)

    B. Vakili

    2015-07-01

    Full Text Available In this paper all-optical switching in a new photonic crystal directional coupler is performed.  The structure of the switch consists of a directional coupler and a separate path for a control signal called “control waveguide”. In contrast to the former reported structures in which the directional couplers are made by removing a row of rods entirely, the directional coupler in our optical switch is constructed by two reduced-radius line-defect waveguides separated by the control waveguide. Furthermore, in our case the background material has the nonlinear Kerr property. Therefore, in the structure of this work, no frequency overlap occurs between the control waveguide mode and the directional coupler modes. It is shown that such a condition provides a very good isolation between the control and the probe signals at the output ports. In the control waveguide, nonlinear Kerr effect causes the required refractive index change by the presence of a high power control (pump signal. Even and odd modes of the coupler are investigated by applying the distribution of the refractive index change in the nonlinear region of a super-cell so that a switching length of about 94 µm is obtained at the wavelength of 1.55 µm. Finally, all-optical switching of the 1.55 µm probe signal using a control signal at the wavelength of 1.3 µm, is simulated through the finite-difference time-domain method, where both signals are desirable in optical communication systems. A very high extinction ratio of 67 dB is achieved and the temporal characteristics of the switch are demonstrated.

  18. Proton damage in linear and digital opto-couplers; Effets des protons sur des optocoupleurs lineaires et numeriques

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, A.; Rax, B.G. [California Institute of Technology, Jet Propulsion Laboratory, Pasadena (United States)

    1999-07-01

    This paper discusses proton degradation of linear and digital opto-couplers. One obvious way to harden opto-coupler technologies is to select LEDs (light emitting diodes) that are more resistant to displacement damage. A direct comparison is made of degradation of a commercial linear opto-coupler from one manufactured with a modified version of the same device with a different LED technology. Other factors, including degradation of optical photoresponse and transistor gain are also discussed, along with basic comparisons of digital and analog opto-couplers. The experimental work has been made with 50 MeV protons. 3 underlying factors contribute to opto-coupler degradation. The most important factor is LED degradation, it is possible to select opto-coupler with double-heterojunction LEDs that are inherently more resistant to displacement damage. The second factor is gain degradation that is particularly important for opto-couplers with sensitive LEDs because the light output decreases so much at low radiation levels. The third factor, optical photoresponse is the largest contribution to CTR (current transfer ratio) degradation for opto-couplers with improved LED hardness. Photoresponse degradation depends on wavelength because the absorption coefficient is wavelength dependent. (A.C.)

  19. Structural and dynamic analysis of an ultra short intracavity directional coupler

    Science.gov (United States)

    Gravé, Ilan; Griffel, Giora; Daou, Youssef; Golan, Gadi

    1997-01-01

    A recently proposed intracavity directional coupler is analysed. Exact analytic expressions for important parameters such as the transmission ratio, the coupling length, and the photon lifetime are given. We show that by controlling the mirror reflectivities of the cavity, it is theoretically possible to reduce the coupling length to a zero limit. The photon lifetime, which governs the dynamic properties of the structure, sets an upper frequency limit of a few hundreds of GHz, which is well over the bandwidth limitation of microwave lumped or travelling wave electrodes. This novel family of intracavity couplers has important applications in the realization of integrated optics circuits for high-speed computing, data processing, and communication.

  20. Ultra-High-Efficiency Apodized Grating Coupler Using a Fully Etched Photonic Crystal

    DEFF Research Database (Denmark)

    Ding, Yunhong; Peucheret, Christophe; Ou, Haiyan

    2013-01-01

    We demonstrate an apodized fiber-to-chip grating coupler using fully etched photonic crystal holes on the silicon-on-insulator platform. An ultra-high coupling efficiency of 1.65 dB (68%) with 3 dB bandwidth of 60 nm is experimentally demonstrated.......We demonstrate an apodized fiber-to-chip grating coupler using fully etched photonic crystal holes on the silicon-on-insulator platform. An ultra-high coupling efficiency of 1.65 dB (68%) with 3 dB bandwidth of 60 nm is experimentally demonstrated....

  1. Testing Procedures and Results of the Prototype Fundamental Power Coupler for the Spallation Neutron Source

    International Nuclear Information System (INIS)

    M. Stirbet; I.E. Campisi; E.F. Daly; G.K. Davis; M. Drury; P. Kneisel; G. Myneni; T. Powers; W.J. Schneider; K.M. Wilson; Y. Kang; K.A. Cummings; T. Hardek

    2001-01-01

    High-power RF testing with peak power in excess of 500 kW has been performed on prototype Fundamental Power Couplers (FPC) for the Spallation Neutron Source superconducting (SNS) cavities. The testing followed the development of procedures for cleaning, assembling and preparing the FPC for installation in the test stand. The qualification of the couplers has occurred for the time being only in a limited set of conditions (travelling wave, 20 pps) as the available RF system and control instrumentation are under improvement

  2. Multi-layered dielectric cladding plasmonic microdisk resonator filter and coupler

    International Nuclear Information System (INIS)

    Han Cheng, Bo; Lan, Yung-Chiang

    2013-01-01

    This work develops the plasmonic microdisk filter/coupler, whose effectiveness is evaluated by finite-difference time-domain simulation and theoretical analyses. Multi-layer dielectric cladding is used to prevent the scattering of surface plasmons (SPs) from a silver microdisk. This method allows devices that efficiently perform filter/coupler functions to be developed. The resonant conditions and the effective refractive index of bounded SP modes on the microdisk are determined herein. The waveguide-to-microdisk distance barely influences the resonant wavelength but it is inversely related to the bandwidth. These findings are consistent with predictions made using the typical ring resonator model.

  3. High-power tests of a single-cell copper accelerating cavity driven by two input couplers

    International Nuclear Information System (INIS)

    Horan, D.; Bromberek, D.; Meyer, D.; Waldschmidt, G.

    2008-01-01

    High-power tests were conducted on a 350-MHz, single-cell copper accelerating cavity driven simultaneously by two H-loop input couplers for the purpose of determining the reliability, performance, and power-handling capability of the cavity and related components, which have routinely operated at 100-kW power levels. The test was carried out utilizing the APS 350-MHz RF Test Stand, which was modified to split the input rf power into two frac12-power feeds, each supplying power to a separate H-loop coupler on the cavity. Electromagnetic simulations of the two-coupler feed system were used to determine coupler match, peak cavity fields, and the effect of phasing errors between the coupler feed lines. The test was conducted up to a maximum total rf input power of 164-kW CW. Test apparatus details and performance data will be presented.

  4. Progress Toward NLC/GLC Prototype Accelerator Structures

    International Nuclear Information System (INIS)

    Wang, J

    2004-01-01

    The accelerator structure groups for NLC (Next Linear Collider) and GLC (Global Linear Colliders) have successfully collaborated on the research and development of a major series of advanced accelerator structures based on room-temperature technology at X-band frequency. The progress in design, simulation, microwave measurement and high gradient tests are summarized in this paper. The recent effort in design and fabrication of the accelerator structure prototype for the main linac is presented in detail including HOM (High Order Mode) suppression and design of HOM couplers and fundamental mode couplers, optimized accelerator cavities as well as plans for future structures

  5. Sometimes Pursuits Don't Pan Out: Anticipated Destinations and Other Caveats--Comment on Hom, Mitchell, Lee, and Griffeth (2012)

    Science.gov (United States)

    Bergman, Mindy E.; Payne, Stephanie C.; Boswell, Wendy R.

    2012-01-01

    Hom, Mitchell, Lee, and Griffeth (2012) presented an extensive review of employee turnover research, reconceptualized the turnover criterion to include multiple destinations, and proposed to expand the predictor domain. They illuminated the multiple destinations employees pursue following turnover. By crossing desire to remain and volitional…

  6. Further Clarification on the Hom, Mitchell, Lee, and Griffeth (2012) Model: Reply to Bergman, Payne, and Boswell (2012) and Maertz (2012)

    Science.gov (United States)

    Griffeth, Rodger W.; Lee, Thomas W.; Mitchell, Terence R.; Hom, Peter W.

    2012-01-01

    In this article, we reply to Bergman, Payne, and Boswell (2012) and Maertz (2012), who commented on our reconceptualization of the employee turnover criterion and proximal withdrawal states (Hom, Mitchell, Lee, & Griffeth, 2012). We agree with some points (e.g., anticipated destinations) but take issue with others (e.g., turnover intentions as…

  7. Current-drive on the Versator-II tokamak with a slotted-waveguide fast-wave coupler

    International Nuclear Information System (INIS)

    Colborn, J.A.

    1987-11-01

    A slotted-waveguide fast-wave coupler has been constructed, without dielectric, and used to drive current on the Versator-II tokamak. Up to 35 kW of net microwave power at 2.45 GHz has been radiated into plasmas with 2 x 10 12 cm -3 ≤ mean of n/sub e/ ≤ 1.2 x 10 13 cm -3 and B/sub tor/ ≅ 1.0 T. The launched spectrum had a peak near N/sub parallel/ = -2.0 and a larger peak near N/sub parallel/ = 0.7. Radiating efficiency of the antenna was roughly independent of antenna position except when the antenna was at least 0.2 cm outside the limiter, in which case the radiating efficiency slightly improved as the antenna was moved farther outside. When the coupler was inside the limiter, radiating efficiency improved moderately with increased mean of n/sub e/. Current-drive efficiency was comparable to that of the slow wave and was not affected when the antenna spectrum was reversed; however, no current was driven for mean of n/sub e/ ≤ 2 x 10 12 cm -3 . These results indicate the fast wave was launched, but a substantial part of the power may have been mode-converted to the slow wave, possibly via a downshift in N/sub parallel/, and these slow waves may have been responsible for most of the driven current. Relevant theory for waves in plasma, current-drive efficiency, and coupling of the slotted-waveguide is discussed, the antenna design method is explained, and future work, including the construction of a much-improved probe-fed antenna, is described. 42 refs., 45 figs

  8. InGaN directional coupler made with a one-step etching technique

    Science.gov (United States)

    Gao, Xumin; Yuan, Jialei; Yang, Yongchao; Zhang, Shuai; Shi, Zheng; Li, Xin; Wang, Yongjin

    2017-06-01

    We propose, fabricate and characterize an on-chip integration of light source, InGaN waveguide, directional coupler and photodiode, in which AlGaN layers are used as top and bottom optical claddings to form an InGaN waveguide for guiding the in-plane emitted light from the InGaN/GaN multiple-quantum-well light-emitting diode (MQW-LED). The difference in etch rate caused by different exposure windows leads to an etching depth discrepancy using the one-step etching technique, which forms the InGaN directional coupler with the overlapped underlying slab. Light propagation results directly confirm effective light coupling in the InGaN directional coupler, which is achieved through high-order guided modes. The InGaN waveguide couples the modulated light from the InGaN/GaN MQW-LED and transfers part of light to the coupled waveguide via the InGaN directional coupler. The in-plane InGaN/GaN MQW-photodiode absorbs the guided light by the coupled InGaN waveguide and induces the photocurrent. The on-chip InGaN photonic integration experimentally demonstrates an in-plane light communication with a data transmission of 50 Mbps.

  9. Very high coupling of TM polarised light in photonic crystal directional couplers

    DEFF Research Database (Denmark)

    Borel, Peter Ingo; Thorhauge, Morten; Frandsen, Lars Hagedorn

    2003-01-01

    The experimental and simulated spectra for TE and TM polarised light for the transmission through photonic crystal directional couplers are presented. The 3D FDTD simulations successfully explain all the major features of the experimental spectra as well as the actual transmission level. Especially...

  10. Optical fiber couplers for spectrophotometry. Perspectives for in-situ on-line and remote measurements

    International Nuclear Information System (INIS)

    Boisde, G.; Linger, C.; Chevalier, G.; Perez, J.J.

    1983-01-01

    Optical fiber couplers have been developed specially for nuclear chemical spectrophotometric applications. Coupling devices are described for TELEPHOT industrial photometers and some commercial spectrophotometer, together with the probes and measurement cells employed. The value of optical multiplexing is mentioned. Non nuclear applications in medical analysis are also mentioned, together with the possibilities offered by these devices for uses other than spectrophotometry [fr

  11. Multipacting Simulations of Tuner-adjustable waveguide coupler (TaCo) with CST

    CERN Document Server

    Shafqat, Nuaman; Wegner, Rolf

    2015-01-01

    Tuner-adjustable waveguide couplers (TaCo) are used to feed microwave power to different RF structures of LINAC4. This paper studies the multipacting phenomenon for TaCo using PIC solver of CST PS. Simulations are performed for complete field sweeps and results are analysed.

  12. Arbitrary-ratio power splitter based on nonlinear multimode interference coupler

    International Nuclear Information System (INIS)

    Tajaldini, Mehdi; Jafri, Mohd Zubir Mat

    2015-01-01

    We propose an ultra-compact multimode interference (MMI) power splitter based on nonlinear effects from simulations using nonlinear modal propagation analysis (NMPA) cooperation with finite difference Method (FDM) to access free choice of splitting ratio. Conventional multimode interference power splitter could only obtain a few discrete ratios. The power splitting ratio may be adjusted continuously while the input set power is varying by a tunable laser. In fact, using an ultra- compact MMI with a simple structure that is launched by a tunable nonlinear input fulfills the problem of arbitrary-ratio in integrated photonics circuits. Silicon on insulator (SOI) is used as the offered material due to the high contrast refractive index and Centro symmetric properties. The high-resolution images at the end of the multimode waveguide in the simulated power splitter have a high power balance, whereas access to a free choice of splitting ratio is not possible under the linear regime in the proposed length range except changes in the dimension for any ratio. The compact dimensions and ideal performance of the device are established according to optimized parameters. The proposed regime can be extended to the design of M×N arbitrary power splitters ratio for programmable logic devices in all optical digital signal processing. The results of this study indicate that nonlinear modal propagation analysis solves the miniaturization problem for all-optical devices based on MMI couplers to achieve multiple functions in a compact planar integrated circuit and also overcomes the limitations of previously proposed methods for nonlinear MMI

  13. Arbitrary-ratio power splitter based on nonlinear multimode interference coupler

    Energy Technology Data Exchange (ETDEWEB)

    Tajaldini, Mehdi [School of Physics, Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia); Young Researchers and Elite Club, Baft Branch, Islamic Azad University, Baft (Iran, Islamic Republic of); Jafri, Mohd Zubir Mat [School of Physics, Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia)

    2015-04-24

    We propose an ultra-compact multimode interference (MMI) power splitter based on nonlinear effects from simulations using nonlinear modal propagation analysis (NMPA) cooperation with finite difference Method (FDM) to access free choice of splitting ratio. Conventional multimode interference power splitter could only obtain a few discrete ratios. The power splitting ratio may be adjusted continuously while the input set power is varying by a tunable laser. In fact, using an ultra- compact MMI with a simple structure that is launched by a tunable nonlinear input fulfills the problem of arbitrary-ratio in integrated photonics circuits. Silicon on insulator (SOI) is used as the offered material due to the high contrast refractive index and Centro symmetric properties. The high-resolution images at the end of the multimode waveguide in the simulated power splitter have a high power balance, whereas access to a free choice of splitting ratio is not possible under the linear regime in the proposed length range except changes in the dimension for any ratio. The compact dimensions and ideal performance of the device are established according to optimized parameters. The proposed regime can be extended to the design of M×N arbitrary power splitters ratio for programmable logic devices in all optical digital signal processing. The results of this study indicate that nonlinear modal propagation analysis solves the miniaturization problem for all-optical devices based on MMI couplers to achieve multiple functions in a compact planar integrated circuit and also overcomes the limitations of previously proposed methods for nonlinear MMI.

  14. The Many Sides of Happy Lim: aka Hom Ah Wing, Lin Jian Fu, Happy Lum, Lin Chien Fu, Hom Yen Chuck, Lam Kin Foo, Lum Kin Foo, Hom, Lim Goon Wing, Lim Gin Foo, Gin Foo Lin, Koon Wing Lim, Henry Chin, Lim Ying Chuck, Lim Ah Wing, et. al.

    Directory of Open Access Journals (Sweden)

    Gordon H. Chang

    2010-03-01

    Full Text Available

    Known to the FBI, INS, and IRS as Mr. Ah Wing Hom, he was also Lin Jian Fu, Jian Fu (Tough Guy, or just Fu to the readers of the many poems and short stories he published in Chinese over four decades in the twentieth century. And to still others, primarily English-readers of his writing, he was Happy Lim, an ironic, even tragically bizarre name, as his life was far from pleasant. On New Year's Day 1986, he died alone in a dingy San Francisco Chinatown bachelor hotel suffering from a bacterial infection and a chronic blood disorder that had required the amputation of all his toes the year before. He was seventy-eight years of age and had spent most of his life within blocks of where he died.

  15. Extremely small polarization beam splitter based on a multimode interference coupler with a silicon hybrid plasmonic waveguide.

    Science.gov (United States)

    Guan, Xiaowei; Wu, Hao; Shi, Yaocheng; Dai, Daoxin

    2014-01-15

    A novel polarization beam splitter (PBS) with an extremely small footprint is proposed based on a multimode interference (MMI) coupler with a silicon hybrid plasmonic waveguide. The MMI section, covered with a metal strip partially, is designed to achieve mirror imaging for TE polarization. On the other hand, for TM polarization, there is almost no MMI effect since the higher-order TM modes are hardly excited due to the hybrid plasmonic effect. With this design, the whole PBS including the 1.1 μm long MMI section as well as the output section has a footprint as small as ∼1.8 μm×2.5 μm. Besides, the fabrication process is simple since the waveguide dimension is relatively large (e.g., the input/output waveguides widths w ≥300 nm and the MMI width w(MMI)=800 nm). Numerical simulations show that the designed PBS has a broad band of ∼80 nm for an ER >10 dB as well as a large fabrication tolerance to allow a silicon core width variation of -30 nm<Δw<50 nm and a metal strip width variation of -200 nm<Δw(m)<0.

  16. Eddy current loss calculation and thermal analysis of axial-flux permanent magnet couplers

    Directory of Open Access Journals (Sweden)

    Di Zheng

    2017-02-01

    Full Text Available A three-dimensional magnetic field analytical model of axial-flux permanent magnet couplers is presented to calculate the eddy current loss, and the prediction of the copper plate temperature under various loads is analyzed. The magnetic field distribution is calculated, and then the eddy current loss is obtained, with the magnetic field analytical model established in cylindrical coordinate. The influence of various loads on eddy current loss is analyzed. Furthermore, a thermal model of axial-flux permanent magnet couplers is established by taking the eddy current loss as the heat source, using the electromagnetic-thermal coupled method. With the help of the thermal model, the influence of various loads on copper plate temperature rise is also analyzed. The calculated results are compared with the results of finite element method and measurement. The comparison results confirm the validity of the magnetic field analytical model and thermal model.

  17. A numerical method for determining the radial wave motion correction in plane wave couplers

    DEFF Research Database (Denmark)

    Cutanda Henriquez, Vicente; Barrera Figueroa, Salvador; Torras Rosell, Antoni

    2016-01-01

    Microphones are used for realising the unit of sound pressure level, the pascal (Pa). Electro-acoustic reciprocity is the preferred method for the absolute determination of the sensitivity. This method can be applied in different sound fields: uniform pressure, free field or diffuse field. Pressure...... solution is an analytical expression that estimates the difference between the ideal plane wave sound field and a more complex lossless sound field created by a non-planar movement of the microphone’s membranes. Alternatively, a correction may be calculated numerically by introducing a full model...... of the microphone-coupler system in a Boundary Element formulation. In order to obtain a realistic representation of the sound field, viscous losses must be introduced in the model. This paper presents such a model, and the results of the simulations for different combinations of microphones and couplers...

  18. Directional multimode coupler for planar magnonics: Side-coupled magnetic stripes

    Energy Technology Data Exchange (ETDEWEB)

    Sadovnikov, A. V., E-mail: sadovnikovav@gmail.com; Nikitov, S. A. [Laboratory “Metamaterials,” Saratov State University, Saratov 410012 (Russian Federation); Kotel' nikov Institute of Radioengineering and Electronics, Russian Academy of Sciences, Moscow 125009 (Russian Federation); Beginin, E. N.; Sheshukova, S. E.; Romanenko, D. V.; Sharaevskii, Yu. P. [Laboratory “Metamaterials,” Saratov State University, Saratov 410012 (Russian Federation)

    2015-11-16

    We experimentally demonstrate spin waves coupling in two laterally adjacent magnetic stripes. By the means of Brillouin light scattering spectroscopy, we show that the coupling efficiency depends both on the magnonic waveguides' geometry and the characteristics of spin-wave modes. In particular, the lateral confinement of coupled yttrium-iron-garnet stripes enables the possibility of control over the spin-wave propagation characteristics. Numerical simulations (in time domain and frequency domain) reveal the nature of intermodal coupling between two magnonic stripes. The proposed topology of multimode magnonic coupler can be utilized as a building block for fabrication of integrated parallel functional and logic devices such as the frequency selective directional coupler or tunable splitter, enabling a number of potential applications for planar magnonics.

  19. High power coupler issues in normal conducting and superconducting accelerator applications

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, H. [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    2001-02-01

    The ceramic material (Al{sub 2}O{sub 3}) commonly used for the klystron output coupler in normal conducting, and for an input coupler to superconducting cavities is one of the most troublesome parts in accelerator applications. But the performance can be improved very much by starting with high purity (>99.9%) alumina powder of controlled grain-size (0.1-0.5-{mu}m), and reducing the magnesium (Mg) sintering-binder to lower the dielectric loss to the order of 10{sup -4} at S-band frequencies. It has been confirmed that the new ceramic can stand a peak S-band frequency rf power of up to 300 MW and 2.5 {mu}sec pulse width. (author)

  20. Compression, splitting and switching of bright and dark solitons in nonlinear directional coupler

    International Nuclear Information System (INIS)

    Mandal, Basanti; Chowdhury, A. Roy

    2006-01-01

    A detailed numerical simulation of the switching, compression and splitting characteristics of various solitary pulses (bright, grey and dark) are carried out by a direct solution of the associated coupled NLS equation. Important physical parameters of the out going pulse such as, intensity distribution, root mean square spatial and temporal width and chirp are calculated. Both the cases of symmetric and asymmetric couplers are considered. The important phenomenon of periodic power transfer from one channel to the other unfolds. The compression varies with the type of pulse launched in the initial channel. It is observed that the chirping of the initial pulse has an optimum value and it vary quite noticeably with the character of the pulse and couplers, symmetric and asymmetric

  1. Measurement of S Parameters ofan Accelerating Structure with Double-Feed Couplers

    CERN Document Server

    Fandos, R; Wuensch, W

    2006-01-01

    A method for measuring the transmission and reflection coefficients of an accelerating structure with double-feed input and output couplers using a 2 port network analyzer is presented. This method avoids the use of magic Ts and hybrids, whose symmetry is not obvious. The procedure is extended to devices with n symmetrical input and m symmetrical output ports. The method to make bead pull measurements for such devices is described.

  2. Switching management in couplers with biharmonic longitudinal modulation of refractive index

    OpenAIRE

    Kartashov, Yaroslav V.; Vysloukh, Victor A.

    2009-01-01

    We address light propagation in couplers with longitudinal biharmonic modulation of refractive index in neighboring channels. While simplest single-frequency out-of-phase modulation allows suppression of coupling for strictly defined set of resonant frequencies, the addition of modulation on multiple frequency dramatically modifies the structure of resonances. Thus, additional modulation on double frequency may suppress primary resonance, while modulation on triple frequency causes fusion of ...

  3. Study on the coaxial couplers for disk and washer loaded accelerating structures

    International Nuclear Information System (INIS)

    Dajkovskij, A.G.; Paramonov, V.V.; Portugalov, Yu.I.; Ryabov, A.D.; Ryabova, T.D.

    1983-01-01

    The paper describes the dispersion and energy properties of the coaxial coupler (CC), which is a promising component for an accelerating system, with the disk and washer (DAW) structure. Resonators, consisting of the DAW structure sections and CC are shown to persist the main advantage of DAW structure, i.e. high stability of the accelerating field distribution. Therewith RF power losses are small. The presence of nonsymetriric modes in the neighbourbood of the operating mode is noted

  4. Ultralow loss, high Q, four port resonant couplers for quantum optics and photonics.

    Science.gov (United States)

    Rokhsari, H; Vahala, K J

    2004-06-25

    We demonstrate a low-loss, optical four port resonant coupler (add-drop geometry), using ultrahigh Q (>10(8)) toroidal microcavities. Different regimes of operation are investigated by variation of coupling between resonator and fiber taper waveguides. As a result, waveguide-to-waveguide power transfer efficiency of 93% (0.3 dB loss) and nonresonant insertion loss of 0.02% (photonic networks.

  5. Straightforward and accurate technique for post-coupler stabilization in drift tube linac structures

    CERN Document Server

    Khalvati, Mohammad Reza

    2016-01-01

    The axial electric field of Alvarez drift tube linacs (DTLs) is known to be susceptible to variations due to static and dynamic effects like manufacturing tolerances and beam loading. Post-couplers are used to stabilize the accelerating fields of DTLs against tuning errors. Tilt sensitivity and its slope have been introduced as measures for the stability right from the invention of post-couplers but since then the actual stabilization has mostly been done by tedious iteration. In the present article, the local tilt-sensitivity slope TS 0 n is established as the principal measure for stabilization instead of tilt sensitivity or some visual slope, and its significance is developed on the basis of an equivalent-circuit diagram of the DTL. Experimental and 3D simulation results are used to analyze its behavior and to define a technique for stabilization that allows finding the best post-coupler settings with just four tilt-sensitivity measurements. CERN ’ s Linac4 DTL Tank 2 and Tank 3 have been stabilized succ...

  6. Multipacting in a coaxial coupler with bias voltage for SRF operation with a large beam current

    Science.gov (United States)

    Liu, Z.-K.; Wang, Ch.; Chang, F.-Y.; Chang, L.-H.; Chang, M.-H.; Chen, L.-J.; Chung, F.-T.; Lin, M.-C.; Lo, C.-H.; Tsai, C.-L.; Tsai, M.-H.; Yeh, M.-S.; Yu, T.-C.

    2016-09-01

    A superconducting radio-frequency (SRF) module is commonly used for a high-energy accelerator; its purpose is to provide energy to the particle beam. Because of the low power dissipation and smaller impedance of a higher-order mode for this module, it can provide more power to the particle beam with better stability through decreasing the couple bunch instability. A RF coupler is necessary to transfer the high power from a RF generator to the cavity. A coupler of coaxial type is a common choice. With high-power operation, it might suffer from multipacting, which is a resonance phenomenon due to re-emission of secondary electrons. Applying a bias voltage between inner and outer conductors of the coaxial coupler might increase or decrease the strength of the multipacting effect. We studied the effect of a bias voltage on multipacting using numerical simulation to track the motion of the electrons. The simulation results and an application for SRF operation with a large beam current are presented in this paper.

  7. Straightforward and accurate technique for post-coupler stabilization in drift tube linac structures

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Khalvati

    2016-04-01

    Full Text Available The axial electric field of Alvarez drift tube linacs (DTLs is known to be susceptible to variations due to static and dynamic effects like manufacturing tolerances and beam loading. Post-couplers are used to stabilize the accelerating fields of DTLs against tuning errors. Tilt sensitivity and its slope have been introduced as measures for the stability right from the invention of post-couplers but since then the actual stabilization has mostly been done by tedious iteration. In the present article, the local tilt-sensitivity slope TS_{n}^{′} is established as the principal measure for stabilization instead of tilt sensitivity or some visual slope, and its significance is developed on the basis of an equivalent-circuit diagram of the DTL. Experimental and 3D simulation results are used to analyze its behavior and to define a technique for stabilization that allows finding the best post-coupler settings with just four tilt-sensitivity measurements. CERN’s Linac4 DTL Tank 2 and Tank 3 have been stabilized successfully using this technique. The final tilt-sensitivity error has been reduced from ±100%/MHz down to ±3%/MHz for Tank 2 and down to ±1%/MHz for Tank 3. Finally, an accurate procedure for tuning the structure using slug tuners is discussed.

  8. Straightforward and accurate technique for post-coupler stabilization in drift tube linac structures

    Science.gov (United States)

    Khalvati, Mohammad Reza; Ramberger, Suitbert

    2016-04-01

    The axial electric field of Alvarez drift tube linacs (DTLs) is known to be susceptible to variations due to static and dynamic effects like manufacturing tolerances and beam loading. Post-couplers are used to stabilize the accelerating fields of DTLs against tuning errors. Tilt sensitivity and its slope have been introduced as measures for the stability right from the invention of post-couplers but since then the actual stabilization has mostly been done by tedious iteration. In the present article, the local tilt-sensitivity slope TSn' is established as the principal measure for stabilization instead of tilt sensitivity or some visual slope, and its significance is developed on the basis of an equivalent-circuit diagram of the DTL. Experimental and 3D simulation results are used to analyze its behavior and to define a technique for stabilization that allows finding the best post-coupler settings with just four tilt-sensitivity measurements. CERN's Linac4 DTL Tank 2 and Tank 3 have been stabilized successfully using this technique. The final tilt-sensitivity error has been reduced from ±100 %/MHz down to ±3 %/MHz for Tank 2 and down to ±1 %/MHz for Tank 3. Finally, an accurate procedure for tuning the structure using slug tuners is discussed.

  9. Coupler Development and Gap Field Analysis for the 352 MHz Superconducting CH-Cavity

    CERN Document Server

    Liebermann, H; Ratzinger, U; Sauer, A C

    2004-01-01

    The cross-bar H-type (CH) cavity is a multi-gap drift tube structure based on the H-210 mode currently under development at IAP Frankfurt and in collaboration with GSI. Numerical simulations and rf model measurements showed that the CH-type cavity is an excellent candidate to realize s.c. multi-cell structures ranging from the RFQ exit energy up to the injection energy into elliptical multi-cell cavities. The reasonable frequency range is from about 150 MHz up to 800 MHz. A 19-cell, β=0.1, 352 MHz, bulk niobium prototype cavity is under development at the ACCEL-Company, Bergisch-Gladbach. This paper will present detailed MicroWave Studio simulations and measurements for the coupler development of the 352 MHz superconducting CH cavity. It will describe possibilities for coupling into the superconducting CH-Cavity. The development of the coupler is supported by measurement on a room temperature CH-copper model. We will present the first results of the measurements of different couplers, e.g. capacitiv...

  10. Fabrication and optical characteristics of silicon-based two-dimensional wavelength division multiplexing splitter with photonic crystal directional waveguide couplers

    International Nuclear Information System (INIS)

    Liu, Cheng-Yang

    2011-01-01

    Photonic crystals have many potential applications because of their ability to control lightwave propagation. We report on the fabrication and optical properties of quasi-two-dimensional photonic crystals with triangular lattice of dielectric rods in air. Rod-type photonic crystal structures were fabricated in silicon by electron beam lithography and dry-etching techniques. Wavelength division multiplexing splitters were fabricated from two-dimensional photonic crystal directional waveguide couplers. Transmission spectra were measured and device operation was shown to be in agreement with theoretical calculations. The splitters can be used in visible light region. Such an approach to photonic element systems should enable new applications for designing components in photonic integrated circuits. -- Highlights: → We report the fabrication and optical properties of rod-type photonic crystal. → The splitter was fabricated by electron beam lithography and dry-etching techniques. → The splitter was composed of directional waveguide couplers. → Measured transmission spectra are in agreement with theoretical calculations. → The splitters can be used in visible light region.

  11. ICRF waveguide couplers. Progress report, February 1983-Aug 1983

    International Nuclear Information System (INIS)

    Scharer, J.E.

    1983-08-01

    Calculations were made for the reflection coefficient from a dielectric loaded TE 10 waveguide operating at 54.8 MHz to a plasma with a prescribed density profile. Optimum waveguide proportions are determined to minimize reflections and the proper match point for a coaxial feed to match the system is determined. Future plans call for fabrication and field measurements of a prototype design and the design of an all metal launcher

  12. Study of higher order modes in superconducting accelerating structures for linac applications

    Energy Technology Data Exchange (ETDEWEB)

    Schuh, Marcel

    2011-06-22

    Higher Order Modes (HOMs) can severely limit the operation of superconducting cavities in a linear accelerator with high beam current, high duty factor and complex pulse structure. Therefore, the full HOM spectrum has to be analysed in detail to identify potentially dangerous modes already during the design phase and to define their damping requirements. For this purpose a dedicated beam dynamics simulation code, Simulation of higher order Mode Dynamics (SMD), focusing on beam-HOM interaction, has been developed in the frame of this project. SMD allows to analyse the beam behaviour under the presence of HOMs, taking into account many important effects, such as for example the HOM frequency spread, beam input jitter, different chopping patterns, as well as klystron and alignment errors. SMD is used to investigate in detail into the effects of HOMs in the Superconducting Proton Linac (SPL) at CERN and in particular their potential to drive beam instabilities in the longitudinal and transverse direction. Based on these results, HOM damping requirements for the HOM coupler design are then defined. In addition, the linear accelerators of the European Spallation Source (ESS) and the Spallation Neutron Source (SNS) are analysed with respect to HOM impact and the results are compared with the SPL simulations. (orig.)

  13. Regional radiometric study over the east of Homs City depending on carborne gamma-ray spectrometry survey

    International Nuclear Information System (INIS)

    Aissa, Mosa

    1994-03-01

    The purpose of regional carborne gamma-ray survey over the east of Homs city is to determine the ground concentration of potassium, uranium and thorium. In the other hand, collecting essential information for future monitoring of any suspected leakage or contamination. In the presented study, we used four channel gamma-ray spectrometer with a 1.8 liter NaI(TI) detector, supplied by the IAEA 1988. About 1205 records of data was accomplished over the area, the car was run at 15-25 km/hr. Potassium, uranium, thorium, and total gamma-ray counts were recorded every 100 m and stored on HD with fiducial. Diurnal variations in the content of atmospheric radon in area were indicated by base station. The background counting-rate variations was obtained from the counts recorded over the Al-Furat river. Stripping ratios and window sensitivities are determined experimentally before the survey operations. The processing of the raw data was done with Pc-computer at SAEC software had written using Fortran, for date validation, editing, corrections, and gridding. The contour maps of seven parameters of Ur, U, Th (ppm), %K, and U/Th, U/K, Th/K ratios had drawn with the help of Surfer program, in which these maps showed without high concentration, They, infect, reflect the natural concentrations of radioactive elements in the concerned area. (Author). 14 refs., 12 figs., 10 tabs

  14. Enxertos valvares aórticos homólogos: estudo experimental em cães

    Directory of Open Access Journals (Sweden)

    Rui Manoel Sequeira de ALMEIDA

    1998-01-01

    Full Text Available Vinte cães foram divididos em dois grupos de dez, sendo um o grupo doador (Grupo 1 e o outro, o receptor (Grupo 2. Todos os animais do grupo 1 foram submetidos a uma toracotomia mediana e sacrificados, para a retirada do coração e da valva aórtica; os cães do grupo 2 foram submetidos a uma laparotomia mediana para o implante das valvas aórticas homólogas na aorta abdominal infra-renal. O peso médio dos cães do grupo 1 era de 5,5 ± 1,7 kg e o diâmetro médio da aorta descendente de 11,8 ± 1,4 mm. No grupo 2 o peso médio era de 11,9 ± 2,3 kg e o diâmetro da aorta abdominal, de 8,8 ± 1,2 mm. A operação no grupo 2 teve como intercorrência a lesão do conduto linfático, em 4 casos, sendo o tempo médio de isquemia, durante o implante do enxerto homólogo, de 37,6 ± 13,3 min. Os animais foram acompanhados por um período de trinta dias, à exceção de 3. Um cão faleceu no décimo dia de pós-operatório por infarto da artéria mesentérica inferior; um segundo foi sacrificado no décimo quarto dia, por apresentar deiscência parcial da ferida cirúrgica, e o terceiro se evadiu no vigésimo quinto dia de pós-operatório. Dois animais apresentaram deiscência da incisão cirúrgica, levando a uma morbidade de 20%. No trigésimo dia, todos os animais sobreviventes foram submetidos a nova laparotomia, quando foram analisados as aderências da cavidade abdominal e o hematoma em torno do enxerto homólogo, e foram aferidas e registradas as pressões proximal e distal ao enxerto valvar (gradiente médio de 25 mmHg. Após o sacrifício do animal, os enxertos foram explantados para a análise das válvulas que eram normais, à excepção de dois, que apresentavam trombos e retração com fibrose, porém, sem significação clínica. Conclui-se que o modelo é viável para estudos futuros sobre valvas aórticas homólogas.The aim of this research was to develop an experimental model, with dogs, to study homologous aortic valve grafts. A

  15. HOM damping and multipacting analysis of the quarter-wave crab cavity

    International Nuclear Information System (INIS)

    Wu, Q.; Belomestnykh, S.; Ben-Zvi, I.; Calaga, R.

    2012-01-01

    The quarter-wave crab cavity design has been analyzed further to accommodate LHC requirements. The goal for the design is to provide strong deflecting voltage to the proton bunches at the IP, while keeping the effective length as short as possible. We will evaluate the higher order mode damping with two or four magnetic coupling dampers installed in different configuration. In this paper, we also show possible multipacting locations which are simulated by 2D and 3D codes.

  16. Multicenter Clinical Trial of Vibroplasty Couplers to Treat Mixed/Conductive Hearing Loss: First Results.

    Science.gov (United States)

    Zahnert, Thomas; Löwenheim, Hubert; Beutner, Dirk; Hagen, Rudolf; Ernst, Arneborg; Pau, Hans-Wilhelm; Zehlicke, Thorsten; Kühne, Hilke; Friese, Natascha; Tropitzsch, Anke; Lüers, Jan-Christoffer; Mlynski, Robert; Todt, Ingo; Hüttenbrink, Karl-Bernd

    2016-01-01

    To evaluate the safety and effectiveness of round window (RW), oval window (OW), CliP and Bell couplers for use with an active middle ear implant. This is a multicenter, long-term, prospective trial with consecutive enrollment, involving 6 university hospitals in Germany. Bone conduction, air conduction, implant-aided warble-tone thresholds and Freiburger monosyllable word recognition scores were compared with unaided preimplantation results in 28 moderate-to-profound hearing-impaired patients after 12 months of follow-up. All patients had previously undergone failed reconstruction surgeries (up to 5 or more). In a subset of patients, additional speech tests at 12 months postoperatively were used to compare the aided with the unaided condition after implantation with the processor switched off. An established quality-of-life questionnaire for hearing aids was used to determine patient satisfaction. Postoperative bone conduction remained stable. Mean functional gain for all couplers was 37 dB HL (RW = 42 dB, OW = 35 dB, Bell = 38 dB, CliP = 27 dB). The mean postoperative Freiburger monosyllable score was 71% at 65 dB SPL. The postimplantation mean SRT50 (speech reception in quiet for 50% understanding of words in sentences) improved on average by 23 dB over unaided testing and signal-to-noise ratios also improved in all patients. The International Outcome Inventory for Hearing Aids (IOI-HA)quality-of-life questionnaire was scored very positively by all patients. A significant improvement was seen with all couplers, and patients were satisfied with the device at 12 months postoperatively. These results demonstrate that an active implant is an advantage in achieving good hearing benefit in patients with prior failed reconstruction surgery. © 2016 S. Karger AG, Basel.

  17. Cold tests of HOM absorber material for the ARIEL eLINAC at TRIUMF

    International Nuclear Information System (INIS)

    Kolb, P.; Laxdal, R.E.; Zvyagintsev, V.; Chao, Y.C.; Amini, B.

    2014-01-01

    At TRIUMF development of a 50 MeV electron accelerator is well under way. Five 1.3 GHz, superconducting 9-cell cavities will accelerate 10 mA electrons to a production target to produce rare isotopes. Each cavity will provide 10 MV accelerating voltage. Plans to upgrade the accelerator in the future to a small ring with ERL capabilities requires that the shunt impedance of the dipole higher order modes to be less than 10MΩ . The design of the accelerator incorporates beam line absorbers to reduce the shunt impedance of potentially dangerous dipole modes. The performance of the absorber is dependant on its electrical conductivity at the operational temperature. Measurements of the electrical conductivity in RF fields of a sample of the proposed beam line absorber material at room temperature and at its operational temperature will be presented for frequencies between 1.3 and 2.4 GHz

  18. Cold tests of HOM absorber material for the ARIEL eLINAC at TRIUMF

    Energy Technology Data Exchange (ETDEWEB)

    Kolb, P., E-mail: kolb@triumf.ca [TRIUMF, Canada' s National Laboratory for Particle and Nuclear Physics, 4004 Wesbrook Mall, Vancouver, B.C., Canada V6T 2A3 (Canada); University of British Columbia, Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, B.C., Canada V6T 1Z1 (Canada); Laxdal, R.E., E-mail: lax@triumf.ca [TRIUMF, Canada' s National Laboratory for Particle and Nuclear Physics, 4004 Wesbrook Mall, Vancouver, B.C., Canada V6T 2A3 (Canada); Zvyagintsev, V.; Chao, Y.C. [TRIUMF, Canada' s National Laboratory for Particle and Nuclear Physics, 4004 Wesbrook Mall, Vancouver, B.C., Canada V6T 2A3 (Canada); Amini, B. [TRIUMF, Canada' s National Laboratory for Particle and Nuclear Physics, 4004 Wesbrook Mall, Vancouver, B.C., Canada V6T 2A3 (Canada); University of British Columbia, Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, B.C., Canada V6T 1Z1 (Canada)

    2014-01-11

    At TRIUMF development of a 50 MeV electron accelerator is well under way. Five 1.3 GHz, superconducting 9-cell cavities will accelerate 10 mA electrons to a production target to produce rare isotopes. Each cavity will provide 10 MV accelerating voltage. Plans to upgrade the accelerator in the future to a small ring with ERL capabilities requires that the shunt impedance of the dipole higher order modes to be less than 10MΩ . The design of the accelerator incorporates beam line absorbers to reduce the shunt impedance of potentially dangerous dipole modes. The performance of the absorber is dependant on its electrical conductivity at the operational temperature. Measurements of the electrical conductivity in RF fields of a sample of the proposed beam line absorber material at room temperature and at its operational temperature will be presented for frequencies between 1.3 and 2.4 GHz.

  19. Studies of HOMs in chains of SRF cavities using state-space concatenation scheme

    Energy Technology Data Exchange (ETDEWEB)

    Galek, Tomasz; Heller, Johann; Flisgen, Thomas; Brackebusch, Korinna; Rienen, Ursula van [Institut fuer Allgemeine Elektrotechnik, Universitaet Rostock (Germany)

    2016-07-01

    The design of modern superconducting radio frequency cavities for acceleration of charged particle bunches requires intensive numerical simulations, as they typically arise as modules of several multi-cell cavities. A wide variety of parameters vital to the proper operation of accelerating cavities must be optimized and studied. One of the most important issues concerning the SRF cavities is the influence of the higher order modes on the beam quality, in this contribution. For TESLA-like structures with 1.3 GHz accelerating mode, higher order modes are calculated up to 4 GHz, the external quality factor and the shunt/geometrical impedance spectra are analyzed. To compute properties of complete RF modules the state-space concatenation scheme is used. The aspects of the concatenation scheme and its application to the bERLinPro's chain of cavities is discussed.

  20. Gaussian beam-to-slab waveguide coupler by graded index photonic crystal lens

    International Nuclear Information System (INIS)

    Bahari, B; Abrishamian, M S

    2013-01-01

    In this numerical study, a Gaussian beam-to-slab waveguide coupler for both modes of TM and TE has been studied. For this purpose, a concrete structure is suggested, in which the graded index photonic crystal lens and the slab waveguide are in the same structure composed of Si material, and can be fabricated with a single-step lithography process. For maximum power coupling, half-holes have been used as an input matching layer. Power coupling of 80% over a 450 nm bandwidth for the TM mode, and 60% over a 180 nm bandwidth for the TE mode is achieved. (paper)

  1. Ellipsoidal diffraction grating as output coupler for quasi-optical gyrotrons

    International Nuclear Information System (INIS)

    Hogge, J.P.; Cao, H.; Tran, T.M.; Tran, M.Q.; Paris, P.J.; Kasparek, W.

    1991-01-01

    The use of a diffraction grating arranged in the -1 Littrow mount as an output coupler for a quasi-optical Fabry-Perot resonator at microwave frequencies (100 GHz) was suggested in 1990. A planar grating with curvilinear grooves (in order to match the Littrow condition everywhere on the surface for a given Gaussian beam) gives a power coupling efficiency of 85% which is limited by the depolarization but gave approximately the same global efficiency because of distortion. We report low power tests on an improvement of the second scheme, based on curved grooves on an ellipsoidal surface, which gives a global efficiency of 94%. (author) 3 figs., 3 refs

  2. TM grating coupler on low-loss LPCVD based Si3N4 waveguide platform

    Science.gov (United States)

    Dabos, G.; Manolis, A.; Giesecke, A. L.; Porschatis, C.; Chmielak, B.; Wahlbrink, T.; Pleros, N.; Tsiokos, D.

    2017-12-01

    We demonstrate, for the first time to our knowledge, a fully etched TM grating coupler for low-loss Low-Pressure-Chemical-Vapor-Deposition (LPCVD) based silicon nitride platform with a coupling loss of 6.5 dB at 1541 nm and a 1 dB bandwidth of 55 nm, addressing applications where TM polarization is a pre-requisite. The proposed GC and the 360 nm × 800 nm strip based Si3N4 waveguides have been fabricated by optical projection lithography using an i-line stepper tool enabling low-cost and mass manufacturing of photonic-integrated-circuits.

  3. OPTICAL FIBRES AND FIBREOPTIC SENSORS: Fibreoptic distributed temperature sensor with spectral filtration by directional fibre couplers

    Science.gov (United States)

    Kuznetsov, A. G.; Babin, Sergei A.; Shelemba, Ivan S.

    2009-11-01

    We demonstrate a Raman-based all-fibre temperature sensor utilising a pulsed erbium fibre laser. The sensor is made of a standard single-mode telecom fibre, SMF-28, and includes a number of directional couplers as band-pass filters. The temperature profile along a 7-km fibreoptic line is measured with an accuracy of 2oC and a spatial resolution of 10 m. In data processing, we take into account the difference in attenuation between the spectral components of the backscatter signal.

  4. Liquid droplet sensing using twisted optical fiber couplers fabricated by hydrofluoric acid flow etching

    Science.gov (United States)

    Son, Gyeongho; Jung, Youngho; Yu, Kyoungsik

    2017-04-01

    We report a directional-coupler-based refractive index sensor and its cost-effective fabrication method using hydrofluoric acid droplet wet-etching and surface-tension-driven liquid flows. The proposed fiber sensor consists of a pair of twisted tapered optical fibers with low excess losses. The fiber cores in the etched microfiber region are exposed to the surrounding medium for efficient interaction with the guided light. We observe that the etching-based low-loss fiber-optic sensors can measure the water droplet volume by detecting the refractive index changes of the surrounding medium around the etched fiber core region.

  5. A novel highly efficient grating coupler with large filling factor used for optoelectronic integration

    International Nuclear Information System (INIS)

    Zhou Liang; Li Zhi-Yong; Zhu Yu; Li Yun-Tao; Yu Yu-De; Yu Jin-Zhong; Fan Zhong-Cao; Han Wei-Hua

    2010-01-01

    A novel highly efficient grating coupler with large filling factor and deep etching is proposed in silicon-on-insulator for near vertical coupling between the rib waveguide and optical fibre. The deep slots acting as high efficient scattering centres are analysed and optimized. As high as 60% coupling efficiency at telecom wavelength of 1550-nm and 3-dB bandwidth of 61 nm are predicted by simulation. A peak coupling efficiency of 42.1% at wavelength 1546-nm and 3-dB bandwidth of 37.6 nm are obtained experimentally. (classical areas of phenomenology)

  6. Frequency support capability of variable speed wind turbine based on electromagnetic coupler

    DEFF Research Database (Denmark)

    You, Rui; Barahona Garzón, Braulio; Chai, Jianyun

    2015-01-01

    In the variable speed wind turbine based on electromagnetic coupler (WT-EMC), a synchronous generator is directly coupled with grid. So like conventional power plants WT-EMC is able to support grid frequency inherently. But due to the reduced inertia of synchronous generator, its frequency support...... capability has to be enhanced. In this paper, the frequency support capability of WT-EMC is studied at three typical wind conditions and with two control strategies-droop control and inertial control to enhance its frequency support capability. The synchronous generator speed, more stable than the grid...

  7. Balanced PIN-TIA photoreceiver with integrated 3 dB fiber coupler for distributed fiber optic sensors

    Science.gov (United States)

    Datta, Shubhashish; Rajagopalan, Sruti; Lemke, Shaun; Joshi, Abhay

    2014-06-01

    We report a balanced PIN-TIA photoreceiver integrated with a 3 dB fiber coupler for distributed fiber optic sensors. This detector demonstrates -3 dB bandwidth >15 GHz and coupled conversion gain >65 V/W per photodiode through either input port of the 3 dB coupler, and can be operated at local oscillator power of +17 dBm. The combined common mode rejection of the balanced photoreceiver and the integrated 3 dB coupler is >20 dB. We also present measurement results with various optical stimuli, namely impulses, sinusoids, and pseudo-random sequences, which are relevant for time domain reflectometry, frequency domain reflectometry, and code correlation sensors, respectively.

  8. Analytical modeling and analysis of magnetic field and torque for novel axial flux eddy current couplers with PM excitation

    Science.gov (United States)

    Li, Zhao; Wang, Dazhi; Zheng, Di; Yu, Linxin

    2017-10-01

    Rotational permanent magnet eddy current couplers are promising devices for torque and speed transmission without any mechanical contact. In this study, flux-concentration disk-type permanent magnet eddy current couplers with double conductor rotor are investigated. Given the drawback of the accurate three-dimensional finite element method, this paper proposes a mixed two-dimensional analytical modeling approach. Based on this approach, the closed-form expressions of magnetic field, eddy current, electromagnetic force and torque for such devices are obtained. Finally, a three-dimensional finite element method is employed to validate the analytical results. Besides, a prototype is manufactured and tested for the torque-speed characteristic.

  9. Comentario: A la Presentación del Hombre de las Cavernas. De los Primeros Homínidos al Neanderthal

    Directory of Open Access Journals (Sweden)

    Gonzalo Correal Urrego

    2015-06-01

    Full Text Available

    Luego de la ponderada exposición del doctor Mendoza, en el corto espacio de que disponemos solo nos resta recapitular algunos de los aspectos más relevantes de su disertación y resumir algunos hitos que precedieron y otros que tuvieron continuidad luego de la aparición de Homo antecesor.

    Los hallazgos paleoantropológicos de las últimas décadas han sido muy importantes. Connotadosinvestigadores discuten en la actualidad si Sahelantropus Tchadensis, Orrin Tugenensis y Ardipithecus ramidus con una antigüedad que los aproxima a los 6 millones de años pueden ser considerados como precursores de los homínidos. Mientras se acrecientan las discusiones sobre los orígenes de los Homínidos, Meave Leakey cree que el fragmento de mandíbula de 5’600.000 años desenterrado en Lothagan, Kenya, en 1967 es el fósil de homínido más antiguo que se ha descubierto hasta hoy; otros hallazgos verificados en las postrimerías de los noventa corresponden a ejemplares del antiguo homínido Australopithecus afarensis descubierto por Donald Johansson, esqueleto que fuera bautizado con el nombre de Lucy.

    Procedente de Hadar, en Etiopía, su edad se calcula en 3´900.000 años. Testimonio silencioso del paso de legendarios primates, son las huellas de pisadas impresas en el fango de la ceniza volcánica de la llanura de Laetoli en Tanzania, y que han sido fechadas en 3’600.000 años. Una mandíbula exhumada en Tanzania por Mary Leaky, fue fechada en 3’500.000 años, y con los hallazgos de Turkana en 1994 el horizonte retrocede otros 600.000 años, con Australopitecus amanensis.

    Hoy se conocen cinco especies de Australopithecus, algunos como Australopithecus garghi elaboraron artefactos líticos muy rudimentarios.

  10. Correspondência eficiente de descritores SIFT para construção de mapas densos de pontos homólogos em imagens de sensoriamento remoto

    Directory of Open Access Journals (Sweden)

    Marcelo Teixeira Silveira

    Full Text Available Métodos automáticos de localização de pontos homólogos em imagens digitais baseados em área, combinados com técnicas de crescimento de região, são capazes de produzir uma malha densa e exata de pontos homólogos. Entretanto, o processo de crescimento de região pode ser interrompido em regiões da imagem, cuja paralaxe no eixo horizontal apresenta variação abrupta. Essa situação geralmente é causada por uma descontinuidade na superfície ou espaço-objeto imageado, tal como um prédio numa cena urbana ou um paredão de exploração de uma mina a céu aberto. Nesses casos, novos pares de pontos homólogos (sementes devem ser introduzidos, normalmente por um operador humano, a partir dos quais o processo é reiniciado. Dependendo do tipo da imagem utilizada e da estrutura 3D da região mapeada, a intervenção humana pode ser considerável. Uma alternativa totalmente automatizada em que se combinam as técnicas SIFT (Scale Invariant Feature Transform, pareamento por mínimos quadrados e crescimento de região foi proposta anteriormente pelos autores. O presente trabalho apresenta uma extensão a essa técnica. Basicamente, propõem-se alterações na etapa de correspondência do SIFT, que exploram características de estereogramas produzidos por sensores aéreos e orbitais. Avaliações experimentais demonstram que as modificações propostas trazem dois tipos de benefícios. Em primeiro lugar, obtém-se um aumento do número de pontos homólogos encontrados, sem aumento correspondente na proporção de falsas correspondências. Em segundo lugar, a carga computacional é reduzida substancialmente.

  11. Pulsed x-ray induced attenuation measurements of single mode optical fibers and coupler materials

    International Nuclear Information System (INIS)

    Johan, A.; Charre, P.

    1994-01-01

    Pulsed X-ray induced transient radiation attenuation measurements of single mode optical fibers have been performed versus total dose, light wavelength, optical power and fiber coil diameter in order to determine the behavior of parameters sensitive to ionizing radiation. The results did not show any photobleaching phenomenon and the attenuation was found independent of the spool diameter. As expected, transient attenuation was lower for higher wave-lengths. The recovery took place in the millisecond range and was independent of total dose, light wavelength and optical power. In optical modules and devices a large range of behaviors was observed according to coupler material i.e., Corning coupler showed a small peak attenuation that remained more than one day later; on the other hand LiTaO 3 material experienced an order of magnitude higher peak attenuation and a recovery in the millisecond range. For applications with optical fibers and integrated optics devices the authors showed that in many cases the optical fiber (length above 100 m) is the most sensitive device in a transient ionizing radiation field

  12. El papel de los juegos en la transmisión cultural: los poemas homéricos y las Olimpiadas en la sociedad oral griega

    Directory of Open Access Journals (Sweden)

    Cantarero, Luis

    2006-12-01

    Full Text Available The author calls attention to the role played by the games in Greek oral tradition. After introducing the most general and defining traits of the games, he argues that those described in the Homeric Poems and practiced in Classical Greece —the Olympian, Pythian, Isthmian and Nemean Games— had two main functions: to provide entertainment and to construct a social order. This social order was epitomized in the values of the Homeric, Olimpian hero: noble, sportsman and amateur.

    La intención de este trabajo es revelar el papel de los juegos en la cultura oral griega. A modo de introducción, resumimos los rasgos más generales y característicos. Una vez situados en ese contexto general, veremos que los juegos descritos en los poemas homéricos y los que se realizaban en la Grecia clásica —Olímpicos, Píticos, Ístmicos y Nemeos— tenían dos funciones primordiales: proporcionar entretenimiento y construir un orden social; orden que, como mostramos aquí, venía sintetizado por los valores que aglutinaba el héroe homérico y olímpico: el noble-deportista-amateur.

  13. Fabrication of etched facets and vertical couplers in InP for packaging and on-wafer test

    NARCIS (Netherlands)

    Lemos Alvares Dos Santos, Rui; D'Agostino, D.; Soares, F. M.; Haghighi, H. Rabbani; Williams, K. A.; Leijtens, X. J. M.

    2016-01-01

    In this letter, the fabrication and the characterization of angled and straight etched facets in InP-based technology are reported. In addition, we report on etched facets combined with coupler mirrors for vertical outcoupling, realized with a wet-etching process.

  14. Optimization of the buffer layer of a side polished fiber slab coupler based on 3 D ADI beam propagation method

    International Nuclear Information System (INIS)

    Lee, Cherl Hee; Kim, Cheol; Park, Jae Hee

    2008-01-01

    A side polished fiber slab coupler has been widely applied to a sensor, which has the advantages of short response time, simple manufacturing process, and reusability as well as in line fiber component. A new type of a side polished fiber sensor providing remote sensing with an improved performance was also recently developed. The side polished fiber slab coupler is modeled as a fiber to planar waveguide coupler with four layers, including the fiber cladding, a buffer layer, planar waveguide and overlay material. The coupling effects by the buffer layer of a side polished fiber slab coupler are analyzed by using 3 dimensional alternating direction implicit (ADI)beam propagation method, where the refractive index and thickness of the buffer layer were tuned for efficient light coupling. The coupling is easily tuned and more occurred by the refractive index and thickness of the buffer layer for efficient coupling. This study tried to optimize the buffer layer parameters for achieving the desired light coupling and power transfer performance

  15. Effective shunt impedance comparison between s-band standing wave accelerators with on-axis and off-axis couplers

    International Nuclear Information System (INIS)

    Schriber, S.O.; Funk, L.W.; Hutcheon, R.M.

    1976-01-01

    The effective shunt impedances of a side-coupled S-band standing wave accelerating structure and a structure employing on-axis couplers have been compared by measuring the energy of accelerated electrons. Criteria for choosing an on-axis coupled structure compared to side-coupled and ''disk and washer'' accelerating structures are given. (author)

  16. Optimizing imbalance and loss in 2 x 2 3dB multimode interference couplers via access waveguide width

    NARCIS (Netherlands)

    Hill, M.T.; Leijtens, X.J.M.; Khoe, G.D.; Smit, M.K.

    2003-01-01

    The imbalance and excess loss in multimode interference couplers with fabrication errors are examined. Remarkably, there exists a number of optimum access waveguide widths which give a minimum imbalance. Furthermore, quite low excess loss can be simultaneously achieved by choosing one particular

  17. 1.28 Tbaud Nyquist-OTDM Transmission over a 7-Core Fiber Using an On-Chip SDM Coupler

    DEFF Research Database (Denmark)

    Hu, Hao; Medhin, Ashenafi Kiros; Ye, Feihong

    2014-01-01

    We have demonstrated the first 1.28-Tbaud Nyquist-OTDM-SDM transmission over a 67.4 - km seven-core fiber with an aggregated data rate of 7.2 Tbit/s using a silicon SDM coupler. 10 - GHz control pulses were transmitted through the center core...

  18. Multipacting Simulations of Tuner-adjustable waveguide coupler (TaCo) with CST Particle Studio®

    CERN Document Server

    Shafqat, N; Wegner, R

    2014-01-01

    Tuner-adjustable waveguide couplers (TaCo) are used to feed microwave power to different RF structures of LINAC4. This paper studies the multipacting phenomenon for TaCo using the PIC solver of CST PS. Simulations are performed for complete field sweeps and results are analysed.

  19. Coupling Characteristics of Fused Optical Fiber Coupler Formed with Single-Mode Fiber and Photonic Crystal Fiber Having Air Hole Collapsed Taper

    Directory of Open Access Journals (Sweden)

    Hirohisa Yokota

    2016-01-01

    Full Text Available Fused coupler forming with a single-mode fiber (SMF and a photonic crystal fiber (PCF is one of the solutions for optical coupling from a light source to a PCF. In this paper, we presented coupling characteristics of a fused fiber coupler formed with an ordinary SMF and a PCF having air hole collapsed taper. A prototype of SMF-PCF coupler with air hole collapsed taper was fabricated using CO2 laser irradiation. The coupling efficiency from SMF to PCF was −6.2 dB at 1554 nm wavelength in the fabricated coupler. The structure of the SMF-PCF coupler to obtain high coupling efficiency was theoretically clarified by beam propagation analysis using an equivalent model of the coupler with simplification. It was clarified that appropriately choosing the prestretched or etched SMF diameter and the length of air hole collapsed region was effective to obtain high coupling efficiency that was a result of high extinction ratio at cross port and low excess loss. We also demonstrated that the diameter of prestretched SMF to obtain high coupling efficiency was insensitive to the air hole diameter ratio to pitch of the PCF in the air hole collapsed SMF-PCF coupler.

  20. Analytical Study on Propagation Dynamics of Optical Beam in Parity-Time Symmetric Optical Couplers

    International Nuclear Information System (INIS)

    Zhou Zheng; Zhang Li-Juan; Zhu Bo

    2015-01-01

    We present exact analytical solutions to parity-time (PT) symmetric optical system describing light transport in PT-symmetric optical couplers. We show that light intensity oscillates periodically between two waveguides for unbroken PT-symmetric phase, whereas light always leaves the system from the waveguide experiencing gain when light is initially input at either waveguide experiencing gain or waveguide experiencing loss for broken PT-symmetric phase. These analytical results agree with the recent experimental observation reported by Rüter et al. [Nat. Phys. 6 (2010) 192]. Besides, we present a scheme for manipulating PT symmetry by applying a periodic modulation. Our results provide an efficient way to control light propagation in periodically modulated PT-symmetric system by tuning the modulation amplitude and frequency. (paper)

  1. High Power Tm3+-Doped Fiber Lasers Tuned by a Variable Reflective Output Coupler

    Directory of Open Access Journals (Sweden)

    Yulong Tang

    2008-01-01

    Full Text Available Wide wavelength tuning by a variable reflective output coupler is demonstrated in high-power double-clad Tm3+-doped silica fiber lasers diode-pumped at ∼790  nm. Varying the output coupling from 96% to 5%, the laser wavelength is tuned over a range of 106  nm from 1949 to 2055  nm. The output power exceeds 20  W over 90-nm range and the maximum output power is 32  W at 1949  nm for 51-W launched pump power, corresponding to a slope efficiency of ∼70%. Assisted with different fiber lengths, the tuning range is expanded to 240  nm from 1866 to 2107  nm with the output power larger than 10  W.

  2. Highly sensitive magnetic field sensor based on microfiber coupler with magnetic fluid

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Longfeng; Pu, Shengli, E-mail: shlpu@usst.edu.cn; Tang, Jiali [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China); Zeng, Xianglong [2Key Laboratory of Specialty Fiber Optics and Optical Access Network, Shanghai University, Shanghai 200072 (China); Lahoubi, Mahieddine [Department of Physics, Faculty of Sciences, Laboratory L.P.S., Badji Mokhtar-Annaba University, P. O. Box 12, 23000 Annaba (Algeria)

    2015-05-11

    A kind of magnetic field sensor using a microfiber coupler (MFC) surrounded with magnetic fluid (MF) is proposed and experimentally demonstrated. As the MFC is strongly sensitive to the surrounding refractive index (RI) and MF's RI is sensitive to magnetic field, the magnetic field sensing function of the proposed structure is realized. Interrogation of magnetic field strength is achieved by measuring the dip wavelength shift and transmission loss change of the transmission spectrum. The experimental results show that the sensitivity of the sensor is wavelength-dependent. The maximum sensitivity of 191.8 pm/Oe is achieved at wavelength of around 1537 nm in this work. In addition, a sensitivity of −0.037 dB/Oe is achieved by monitoring variation of the fringe visibility. These suggest the potential applications of the proposed structure in tunable all-in-fiber photonic devices such as magneto-optical modulator, filter, and sensing.

  3. Highly sensitive magnetic field sensor based on microfiber coupler with magnetic fluid

    International Nuclear Information System (INIS)

    Luo, Longfeng; Pu, Shengli; Tang, Jiali; Zeng, Xianglong; Lahoubi, Mahieddine

    2015-01-01

    A kind of magnetic field sensor using a microfiber coupler (MFC) surrounded with magnetic fluid (MF) is proposed and experimentally demonstrated. As the MFC is strongly sensitive to the surrounding refractive index (RI) and MF's RI is sensitive to magnetic field, the magnetic field sensing function of the proposed structure is realized. Interrogation of magnetic field strength is achieved by measuring the dip wavelength shift and transmission loss change of the transmission spectrum. The experimental results show that the sensitivity of the sensor is wavelength-dependent. The maximum sensitivity of 191.8 pm/Oe is achieved at wavelength of around 1537 nm in this work. In addition, a sensitivity of −0.037 dB/Oe is achieved by monitoring variation of the fringe visibility. These suggest the potential applications of the proposed structure in tunable all-in-fiber photonic devices such as magneto-optical modulator, filter, and sensing

  4. Monolithic optofluidic mode coupler for broadband thermo- and piezo-optical characterization of liquids.

    Science.gov (United States)

    Pumpe, Sebastian; Chemnitz, Mario; Kobelke, Jens; Schmidt, Markus A

    2017-09-18

    We present a monolithic fiber device that enables investigation of the thermo- and piezo-optical properties of liquids using straightforward broadband transmission measurements. The device is a directional mode coupler consisting of a multi-mode liquid core and a single-mode glass core with pronounced coupling resonances whose wavelength strongly depend on the operation temperature. We demonstrated the functionality and flexibility of our device for carbon disulfide, extending the current knowledge of the thermo-optic coefficient by 200 nm at 20 °C and uniquely for high temperatures. Moreover, our device allows measuring the piezo-optic coefficient of carbon disulfide, confirming results first obtained by Röntgen in 1891. Finally, we applied our approach to obtain the dispersion of the thermo-optic coefficients of benzene and tetrachloroethylene between 450 and 800 nm, whereas no data was available for the latter so far.

  5. Broad-band anti-reflection coupler for a : Si thin-film solar cell

    International Nuclear Information System (INIS)

    Lo, S.-S.; Chen, C.-C.; Garwe, Frank; Pertch, Thomas

    2007-01-01

    This work numerically demonstrates a new anti-reflection coupler (ARC) with high coupling efficiency in a Si substrate solar cell. The ARC in which the grating is integrated on a glass encapsulation and a three-layer impedance match layer is proposed. A coupling efficiency of 90% is obtained at wavelengths between 350 and 1200 nm in the TE and TM modes when the incident angle is less than 30 0 . In comparison with a 1μm absorber layer, the integrated absorption of an a-Si thin-film solar cell without a new ARC is doubled, at long wavelengths (750 nm ≤ λ ≤ 1200 nm), as calculated by FDTD method

  6. Study of a superconducting spoke-type cavity and of its associated power coupler; Etude d'une cavite acceleratrice supraconductrice de type spoke et de son coupleur de puissance associe

    Energy Technology Data Exchange (ETDEWEB)

    Mielot, Ch

    2004-12-01

    This work deals with the study of a spoke-type cavity and its associated power coupler. The results of this study are used in the framework of the high power proton linear accelerator of the experimental accelerator-driven system project (XADS). The cavity (F=352 MHz, {beta}=0.35) was tested at 4 K and 2 K. The results at 4 K gave good margins toward XADS requirements that increase the reliability of a spoke based driver. At 2 K the accelerating field reached is the highest in the world for spoke cavities: 16 MV/M. The position and diameter of the coupling have been optimized in order to decrease the HF losses and avoid multi-factor risk. In order to decrease HF losses (taking into account the 20 kW power fed into the cavity) the electric coupling mode has been chosen. Different types of ceramic windows have been studied in order to make this critical point of the coupler reliable: coaxial disk with or without chokes or empty coaxial cylinder. The optimization process focused on the reflected power, the losses in the ceramic and the surface electric field. The risk with chokes has been modeled and studied with the propagation lines theory. A systematic study of the different windows has been done regarding the geometrical parameters. The disk without chokes seems to be a good solution for our application. The power source will be a solid state amplifier (for reliability and modularity reasons). An all over coaxial coupler can be designed and will be fabricated and tested soon. (author)

  7. Contribución al conocimiento de las interacciones entre plantas, hormigas y homópteros en bosques secos de Colombia

    Directory of Open Access Journals (Sweden)

    Ramírez Mónica

    2001-12-01

    Full Text Available Las interacciones entre plantas y hormigas y entre plantas, hormigas y homópteros se estudiaron en 248 estaciones de muestreo situadas en nueve fragmentos de bosque seco del valle geográfico del río Cauca, entre enero y junio de 1997. Se registraron 352 interacciones que involucran 91 especies vegetales, hormigas de 67 especies y homópteros pertenecientes a nueve familias. El 4 7% de las asociaciones registradas implica el uso por parte de las hormigas de diferentes estructuras de las plantas (p. e. raíces de las epífitas, domacios en los tallos, hojarasca acumulada entre ramas y hojas, brácteas y peciolos de Heliconia spp. como refugios temporales o sitios de anidamiento. El restante 53% involucra la recolección de miel de homópteros y de sustancias azucaradas en nectarios extraflorales. asmannia auropunctata (17%, Dolichoderus bispinosus (11% Y Brachymyrmex heeri (7% fueron las especies de hormigas registradas con mayor frecuencia. Las plantas más utilizadas fueron Heliconia stricta (8%, Philodendron sp. nov. (7% y Passiflora coriacea (5%. Entre las relaciones observadas, predominan las de tipo generalista, en que las hormigas explotan diferentes recursos aparentemente en forma oportunista y las plantas pueden encontrarse en buen estado a pesar de la ausencia de las hormigas.Interactions between ants and plants and those involving homopterans were studied in 248 sampling points located within nine tropical decidous forest fragments in the Cauca river Valley, between january and june, 1997. A total of 352 interactions were recorded involving 91 plant species, 67 ant species and Homoptera belonging to nine families. 47% ofthe interactions involved ants using different plant structures (such as epiphyte roots, domacia, litter collected in branches and leaves, bracts and petioles of Heliconia spp. as nesting sites or temporary refugia. The remaining 53% involved the collection of homopteran honeydew and sugary substances from extrafloral

  8. Design Topics for Superconducting RF Cavities and Ancillaries

    International Nuclear Information System (INIS)

    Padamsee, H

    2014-01-01

    RF superconductivity has become a major subfield of accelerator science. There has been an explosion in the number of accelerator applications and in the number of laboratories engaged. The first lecture at this meeting of the CAS presented a review of fundamental design principles to develop cavity geometries to accelerate velocity-of-light particles (β = v/c ~ 1), moving on to the corresponding design principles for medium-velocity (medium-β) and low-velocity (low-β) structures. The lecture included mechanical design topics. The second lecture dealt with input couplers, higher-order mode extraction couplers with absorbers, and tuners of both the slow and fast varieties

  9. Design Topics for Superconducting RF Cavities and Ancillaries

    Energy Technology Data Exchange (ETDEWEB)

    Padamsee, H [Cornell University, CLASSE (United States)

    2014-07-01

    RF superconductivity has become a major subfield of accelerator science. There has been an explosion in the number of accelerator applications and in the number of laboratories engaged. The first lecture at this meeting of the CAS presented a review of fundamental design principles to develop cavity geometries to accelerate velocity-of-light particles (β = v/c ~ 1), moving on to the corresponding design principles for medium-velocity (medium-β) and low-velocity (low-β) structures. The lecture included mechanical design topics. The second lecture dealt with input couplers, higher-order mode extraction couplers with absorbers, and tuners of both the slow and fast varieties.

  10. A propos de la formule homérique « enenipen epos t’ephat’ ek t’onomazen »

    Directory of Open Access Journals (Sweden)

    Rossella Saetta-Cottone

    2006-05-01

    Full Text Available Cet article propose une analyse des huit occurrences de la formule homérique epos t’ephat’ ek t’onomazen qui sont précédées, dans le premier hémistiche de l’hexamètre, par le verbe enenipein, dans le but de mettre en lumière la signification particulière qu’y recouvre le verbe onomazein  « apostropher par des mots injurieux ».This article aims to analyze the eight cases of the homeric formula epos t’ephat’ ek t’onomazen they are preceeded, within the first hemistich of the hexametre, by the verb enenipein, so as to clarify the particular meaning that recovers here the verb onomazein « to shout at with injurious words ».

  11. Desenvolvimento de uma aplicação para reconhecer significado de palavras homônimas utilizando redes neurais artificiais

    Directory of Open Access Journals (Sweden)

    Eduardo Gabriel Côrtes

    2016-07-01

    Full Text Available Este trabalho propõe desenvolver uma aplicação para auxiliar no entendimento do significado de palavras ambíguas da língua portuguesa, que dependem necessariamente do contexto para serem identificadas. A aplicação foi implementada na linguagem de programação JAVA, utilizando a IDE NetBeans, juntamente com a ferramenta ADReNA, que permitiu modelar e treinar a rede neural artificial backpropagation. Foram desenvolvidas duas versões da aplicação, que se diferenciam pela forma que representam a camada de entrada da rede neural artificial. Testes realizados mostraram que a forma que a rede neural é representada gera influência em seus resultados. Após a realização dos testes, a aplicação se mostrou promissora no reconhecimento de significados de palavras homônimas.

  12. Evaluación de la inmunogenicidad y la capacidad protectora homóloga de un candidato vacunal tetravalente de Leptospira, para uso veterinario

    Directory of Open Access Journals (Sweden)

    Yaritza Cuba-Romero

    2016-12-01

    Full Text Available La inmunogenicidad es un parámetro importante en estudios de inmunógenos. En la leptospirosis la respuesta inmune humoral es vital para la resistencia a la infección, de ahí que este trabajo se haya propuesto evaluar la inmunogenicidad y la capacidad protectora homóloga de un candidato tetravalente que incluye al serogrupo Ballum en su formulación. Se trabajó con la cepa 245-12 clasificada como L. borgpetersenii serovar Ballum, aislada a partir de un caso confirmado de leptospirosis. Con esta cepa previamente caracterizada desde el punto de vista de su virulencia, se formularon 5 lotes de una preparación vacunal tetravalente, la cual contiene además las cepas Canicola, Icterohaemorrhagiae y Pomona contenidas en la vacuna Polivalente-Leptospira, de uso veterinario. Se evaluó la inmunogenicidad de esta preparación, mediante microaglutinación y la capacidad de protección homóloga en hámster sirio dorado, frente al reto con 100 DL50. Los animales se inmunizaron con dos dosis de la vacuna (0,1mL con un intervalo de 15 días, el reto se llevó a cabo a los 14 días de concluido el esquema de inmunización. Los resultados obtenidos se compararon con los de la vacuna Polivalente-Leptospira. Todos los lotes de preparación tetravalente formulados cumplieron satisfactoriamente con los controles de calidad. Los lotes formulados en este estudio mostraron una significativa inmunogenicidad y capacidad de protección homologa frente al serogrupo Ballum, y lograron eliminar el estado de portador en los animales inmunizados. El presente trabajo, por primera vez, sienta las bases para formulaciones vacunales novedosas, en animales, conteniendo el serogrupo Ballum.

  13. Alterações histológicas em enxerto de osso homógeno preparado e armazenado com duas técnicas diferentes

    Directory of Open Access Journals (Sweden)

    Duarte da Silva Alfredo Benjamin

    2000-01-01

    Full Text Available Esta pesquisa analisa as alterações histológicas de enxerto ósseo homógeno preparado de diferentes modos. Em um grupo, ossos metatársicos-l de ratos foram armazenados a -70° Celsius e em outro grupo, os ossos foram descalcificados e estocados em temperatura ambiente após terem sido liofilizados. Esses ossos foram enxertados nas regiões inguinais de ratos e retirados para estudo histológico no trigésimo dia de pós-operatório. Macroscopicamente os ossos não descalcificados e armazenados a -70°C estavam envoltos por uma cápsula delgada, facilmente desprendida e apresentavam consistência de osso cortical. Microscopicamente observou-se absorção da superfície endostal com diminuição da camada cortical e aumento da cavidade medular. A cortical estava sofrendo processo de reabsorção e a superfície óssea externa possuía uma cápsula fibrosa delgada e células inflamatórias. Os ossos descalcificados e liofilizados, na macroscopia, apresentavam-se de consistência amolecida e estavam envoltos por uma cápsula espessa e firmemente aderida. Microscopicamente, a maior parte da arquitetura óssea estava preenchida por material acelular e avascular, muito semelhante à cartilagem e envolvendo o tecido, uma cápsula fibrosa espessa com células inflamatórias. Portanto, existiam diferenças histológicas dos enxertos ósseos homógenos, dependendo do preparo e do armazenamento do osso.

  14. Calculation of Wakefields and Higher Order Modes for the New Design of the Vacuum Chamber of the ALICE Experiment for the HL-LHC

    CERN Document Server

    Wanzenberg, Rainer; CERN. Geneva. ATS Department

    2016-01-01

    The High Luminosity Large Hadron Collider (HL-LHC) project was started with the goal to extend the discovery potential of the Large Hadron Collider (LHC). The HL-LHC study implies also an upgraded dimensions of the ALICE beam pipe. The trapped monopole and dipole Higher Order Modes (HOMs) and the short range wakefields for the new design of the ALICE vacuum chamber were calculated with help of the computer codes MAFIA and ECHO2D. The results of the short range wakefields calculations and the HOMs calculations for the ALICE vacuum chamber with new dimensions are presented in this report. The short range wakefields are presented in terms of longitudinal and transverse wake potentials and also in terms of loss and kick parameters. The frequency, the loss parameter, the R/Q and the Qvalues and also power loss parameters are presented as result of the HOMs calculations and can be converted into impedance values.

  15. Analysis and comparison between electric and magnetic power couplers for accelerators in Free Electron Lasers (FEL)

    Energy Technology Data Exchange (ETDEWEB)

    Serpico, C., E-mail: claudio.serpico@elettra.eu [Elettra - Sincrotrone Trieste, Trieste (Italy); Grudiev, A. [CERN, Geneva (Switzerland); Vescovo, R. [University of Trieste, Trieste (Italy)

    2016-10-11

    Free-electron lasers represent a new and exciting class of coherent optical sources possessing broad wavelength tunability and excellent optical-beam quality. The FERMI seeded free-electron laser (FEL), located at the Elettra laboratory in Trieste, is driven by a 200 m long, S-band linac: the high energy part of the linac is equipped with 6 m long backward traveling wave (BTW) structures. The structures have small iris radius and a nose cone geometry which allows for high gradient operation. Development of new high-gradient, S-band accelerating structures for the replacement of the existing BTWs is under consideration. This paper investigates two possible solutions for the RF power couplers suitable for a linac driven FEL which require reduced wakefields effects, high operating gradient and very high reliability. The first part of the manuscript focuses on the reduction of residual field asymmetries, while in the second analyzes RF performances, the peak surface fields and the expected breakdown rate. In the conclusion, two solutions are compared and pros and cons are highlighted.

  16. Analysis and comparison between electric and magnetic power couplers for accelerators in Free Electron Lasers (FEL)

    Science.gov (United States)

    Serpico, C.; Grudiev, A.; Vescovo, R.

    2016-10-01

    Free-electron lasers represent a new and exciting class of coherent optical sources possessing broad wavelength tunability and excellent optical-beam quality. The FERMI seeded free-electron laser (FEL), located at the Elettra laboratory in Trieste, is driven by a 200 m long, S-band linac: the high energy part of the linac is equipped with 6 m long backward traveling wave (BTW) structures. The structures have small iris radius and a nose cone geometry which allows for high gradient operation. Development of new high-gradient, S-band accelerating structures for the replacement of the existing BTWs is under consideration. This paper investigates two possible solutions for the RF power couplers suitable for a linac driven FEL which require reduced wakefields effects, high operating gradient and very high reliability. The first part of the manuscript focuses on the reduction of residual field asymmetries, while in the second analyzes RF performances, the peak surface fields and the expected breakdown rate. In the conclusion, two solutions are compared and pros and cons are highlighted.

  17. Nanophotonic lab-on-a-chip platforms including novel bimodal interferometers, microfluidics and grating couplers.

    Science.gov (United States)

    Duval, Daphné; González-Guerrero, Ana Belén; Dante, Stefania; Osmond, Johann; Monge, Rosa; Fernández, Luis J; Zinoviev, Kirill E; Domínguez, Carlos; Lechuga, Laura M

    2012-05-08

    One of the main limitations for achieving truly lab-on-a-chip (LOC) devices for point-of-care diagnosis is the incorporation of the "on-chip" detection. Indeed, most of the state-of-the-art LOC devices usually require complex read-out instrumentation, losing the main advantages of portability and simplicity. In this context, we present our last advances towards the achievement of a portable and label-free LOC platform with highly sensitive "on-chip" detection by using nanophotonic biosensors. Bimodal waveguide interferometers fabricated by standard silicon processes have been integrated with sub-micronic grating couplers for efficient light in-coupling, showing a phase resolution of 6.6 × 10(-4)× 2π rad and a limit of detection of 3.3 × 10(-7) refractive index unit (RIU) in bulk. A 3D network of SU-8 polymer microfluidics monolithically assembled at the wafer-level was included, ensuring perfect sealing and compact packaging. To overcome some of the drawbacks inherent to interferometric read-outs, a novel all-optical wavelength modulation system has been implemented, providing a linear response and a direct read-out of the phase variation. Sensitivity, specificity and reproducibility of the wavelength modulated BiMW sensor has been demonstrated through the label-free immunodetection of the human hormone hTSH at picomolar level using a reliable biofunctionalization process.

  18. New window design options for CEBAF energy upgrade

    International Nuclear Information System (INIS)

    Phillips, L.; Mammosser, J.; Nguyen, V.

    1997-01-01

    As the Jefferson Laboratory upgrades the existing CEBAF electron accelerator to operate at higher energies, the fundamental power coupler windows will be required to operate with lower RF dissipation and increased immunity to radiation from cavity field emission. New designs and modifications to existing designs which can achieve these goals are described

  19. Degradação dos homólogos do alquilbenzeno linear sulfonato em lodo anaeróbio disperso

    Directory of Open Access Journals (Sweden)

    Luiz Galdino Silva

    Full Text Available RESUMO: Avaliou-se a degradação anaeróbia do alquilbenzeno linear sulfonato (LAS e seus homólogos em experimento em escala de laboratório. Foi usado lodo disperso para minimizar o efeito da adsorção. Em primeiro lugar, determinaram-se a maior concentração de LAS (substrato e a menor concentração de etanol (cossubstrato que manteriam os micro-organismos ativos, resultando em 25 e 200 mg.L-1, nessa ordem. Posteriormente, o experimento (90 dias foi realizado em um reator somente com etanol (controle e outro (reator teste, triplicata com ambos os substratos nas concentrações anteriores. Os micro-organismos apresentaram crescimento exponencial em 48 h para os 2 reatores; não ocorreu toxicidade pelo LAS no reator teste durante esse período inicial, quando o etanol foi todo consumido. Após então, houve decréscimo de micro-organismos, indicando possível toxicidade por LAS ou intermediários. Observou-se também a diminuição ou ausência da produção de ácidos graxos voláteis e de metano. Portanto, com lodo disperso, a maior parcela da remoção foi por conta da biodegradação, porém, com formação de intermediários que não o acetato nem o metano, apontando a inibição à acidogênese e à metanogênese. Ao final, a remoção do LAS foi de 35% por biodegradação e apenas 0,35% por adsorção ao lodo. A ordem preferencial de biodegradação para os homólogos foi de C13 para C12, C11 e C10, com percentual de degradação em relação à massa inicial de 49, 31, 24 e 17%, respectivamente. A mesma ordem deu-se para a adsorção, da maior para a menor cadeia alquílica, sendo a remoção por adsorção de 0,85; 0,32; 0,13 e 0,01%, respectivamente.

  20. On-chip broadband ultra-compact optical couplers and polarization splitters based on off-centered and non-symmetric slotted Si-wire waveguides

    Science.gov (United States)

    Haldar, Raktim; Mishra, V.; Dutt, Avik; Varshney, Shailendra K.

    2016-10-01

    In this work, we propose novel schemes to design on-chip ultra-compact optical directional couplers (DC) and broadband polarization beam splitters (PBS) based on off-centered and asymmetric dielectric slot waveguides, respectively. Slot dimensions and positions are optimized to achieve maximum coupling coefficients between two symmetric and non-symmetric slotted Si wire waveguides through overlap integral method. We observe >88% of enhancement in the coupling coefficients when the size-optimized slots are placed in optimal positions, with respect to the same waveguides with no slot. When the waveguides are parallel, in that case, a coupling length as short as 1.73 μm is accomplished for TM mode with the off-centered and optimized slots. This scheme enables us to design optical DC with very small footprint, L c ∼ 0.9 μm in the presence of S-bends. We also report a compact (L c ∼ 1.1 μm) on-chip broadband PBS with hybrid slots. Extinction ratios of 13 dB and 22.3 dB are realized with very low insertion loss (0.055 dB and 0.008 dB) for TM and TE modes at 1.55 μm, respectively. The designed PBS exhibits a bandwidth of 78 nm for the TM mode (C-and partial L-bands) and >100 nm for the TE mode (S + C + L wavelength bands). Such on-chip devices can be used to design compact photonic interconnects and quantum information processing units efficiently. We have also investigated the fabrication tolerances of the proposed devices and described the fabrication steps to realize such hybrid devices. Our results are in good agreement with 3D FDTD simulations.

  1. Design of a Ku band miniature multiple beam klystron

    Energy Technology Data Exchange (ETDEWEB)

    Bandyopadhyay, Ayan Kumar, E-mail: ayan.bandyopadhyay@gmail.com; Pal, Debasish; Kant, Deepender [Microwave Tubes Division, CSIR-CEERI, Pilani, Rajasthan-333031 (India); Saini, Anil; Saha, Sukalyan; Joshi, Lalit Mohan

    2016-03-09

    The design of a miniature multiple beam klystron (MBK) working in the Ku-band frequency range is presented in this article. Starting from the main design parameters, design of the electron gun, the input and output couplers and radio frequency section (RF-section) are presented. The design methodology using state of the art commercial electromagnetic design tools, analytical formulae as well as noncommercial design tools are briefly presented in this article.

  2. Design of large aperture 500 MHz 5-cell superconducting cavity

    International Nuclear Information System (INIS)

    Wei Yelong; Feng Ziqiang; Lu Changwang; Yu Haibo; Liu Jianfei; Hou Hongtao; Ma Zhenyu; Mao Dongqing

    2012-01-01

    With the potential application of Energy Recovery Linac (ERL), the superconducting (SC) cavities were developed to deliver much higher current than before. Nowadays, the current of the international SC accelerator designed has already exceeded 100 mA. This paper presents the design of a new 500 MHz 5-cell SC cavity (SINAP 5-cell cavity), in which the parameters r/Q= 515.5 Ω of the fundamental mode and the geometry factor G=275.8 are under an acceptable Radio Frequency (RF) field level. (B peak /E acc =4.31 mT/MV/m and E peak /E acc =2.48). This design employs a larger beam pipe to propagate the Higher Order Modes (HOMs) out of the cavity and increases the damping efficiently for the dangerous HOMs. By simulation technique, it has been found that almost all the dangerous HOMs (including TE 111 , TM 110 , and TM 011 ) can be propagated into the beam pipe and are absorbed by ferrite absorbers, when the beam pile is enlarged. Finally, the loss factor for the new 5-cell cavity is also calculated. (authors)

  3. A Novel Wind Turbine Concept Based on an Electromagnetic Coupler and the Study of Its Fault Ride-through Capability

    DEFF Research Database (Denmark)

    You, Rui; Barahona Garzón, Braulio; Chai, Jianyun

    2013-01-01

    This paper presents a novel type of variable speed wind turbine with a new drive train different from the variable speed wind turbine commonly used nowadays. In this concept, a synchronous generator is directly coupled with the grid, therefore, the wind turbine transient overload capability...... and the synchronous generator, so the synchronous generator torque oscillations during a grid fault are not transmitted to the gearbox. The EMCD is composed of an electromagnetic coupler and a one quadrant operation converter with reduced capability and low cost. A control strategy for the new wind turbine...

  4. Cross two photon absorption in a silicon photonic crystal waveguide fiber taper coupler with a physical junction

    Energy Technology Data Exchange (ETDEWEB)

    Sarkissian, Raymond, E-mail: RaymondSark@gmail.com; O' Brien, John [Electrophysics department, University of Southern California, Los Angeles, California 90089 (United States)

    2015-01-21

    Cross two photon absorption in silicon is characterized using a tapered fiber photonic crystal silicon waveguide coupler. There is a physical junction between the tapered fiber and the waveguide constituting a stand-alone device. This device is used to obtain the spectrum for cross two photon absorption coefficient per unit volume of interaction between photons of nondegenerate energy. The corresponding Kerr coefficient per unit volume of interaction is also experimentally extracted. The thermal resistance of the device is also experimentally determined and the response time of the device is estimated for on-chip all-optical signal processing and data transfer between optical signals of different photon energies.

  5. Laser phase and frequency noise measurement by Michelson interferometer composed of a 3 × 3 optical fiber coupler.

    Science.gov (United States)

    Xu, Dan; Yang, Fei; Chen, Dijun; Wei, Fang; Cai, Haiwen; Fang, Zujie; Qu, Ronghui

    2015-08-24

    A laser phase and frequency noise measurement method by an unbalanced Michelson interferometer composed of a 3 × 3 optical fiber coupler is proposed. The relations and differences of the power spectral density (PSD) of differential phase and frequency fluctuation, PSD of instantaneous phase and frequency fluctuation, phase noise and linewidth are derived strictly and discussed carefully. The method obtains the noise features of a narrow linewidth laser conveniently without any specific assumptions or noise models. The technique is also used to characterize the noise features of a narrow linewidth external-cavity semiconductor laser, which confirms the correction and robustness of the method.

  6. THE JLAB AMPERE-CLASS CRYOMODULE CONCEPTUAL DESIGN

    International Nuclear Information System (INIS)

    Robert Rimmer; Edward Daly; William Hicks; James Henry; Joseph Preble; Mircea Stirbet; Haipeng Wang; Katherine Wilson; Genfa Wu; Gianluigi Ciovati; Thomas Elliott; Peter Kneisel; Stephen Manning; Robert Manus; Karl Smith; Lynn Vogel; Larry Turlington

    2006-01-01

    For the next generation of compact high-power FELs a new cryomodule is required that is capable of accelerating up to Ampere levels of beam current. Challenges include strong HOM damping, high HOM power and high fundamental-mode power (in operating scenarios without full energy recovery). For efficient use of space a high real-estate gradient is desirable and for economic operation good fundamental-mode efficiency is important. The technology must also be robust and should be based on well-proven and reliable technologies. For Ampere-class levels of beam current both halo interception and beam break-up (BBU) are important considerations. These factors tend to drive the designs to lower frequencies where the apertures are larger and the transverse impedances are lower. To achieve these goals we propose to use a compact waveguide-damped multi-cell cavity packaged in an SNS-style cryomodule

  7. LiNbO/sub 3/:Ti directional-coupler modulators for high-bandwidth, single-shot instrumentation systems operating at 800 nm

    International Nuclear Information System (INIS)

    Lowry, M.; Jander, D.; Lancaster, G.; Kwiat, P.; McWright, G.; Peterson, R.T.; Tindall, W.; Roeske, F.

    1987-01-01

    The authors update their work on optical directional-coupler modulators (ODCMs) for single-shot, analog instrumentation systems operating at -- 800 nm. They can now fabricate directional-coupler devices that have one input and two output pigtails with insertion losses of 8.9 dB on average. Data for the ODCMs indicate an impulse response of less than 40 ps. They have implemented these devices in an ultrafast, x-ray measurement system. They discuss our data from this implementation and their implications for continued ODCM development

  8. Photonic crystal fiber design for broadband directional coupling

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Bang, Ole; Bjarklev, Anders Overgaard

    2004-01-01

    A novel design for a broadband directional coupler based on a photonic crystal fiber is investigated numerically. It is shown that suitable index-depressing doping of the core regions in an index-guiding twin-core photonic crystal fiber can stabilize the coupling coefficient between the cores over...

  9. Progress on the high-current 704 MHz superconducting RF cavity at BNL

    International Nuclear Information System (INIS)

    Xu, W.; Astefanous, C.; Belomestnykh, S.; Ben-Zvi, I.

    2012-01-01

    The 704 MHz high current superconducting cavity has been designed with consideration of both performance of fundamental mode and damping of higher order modes. A copper prototype cavity was fabricated by AES and delivered to BNL. RF measurements were carried out on this prototype cavity, including fundamental pass-band and HOM spectrum measurements, HOM studies using bead-pull setup, prototyping of antenna-type HOM couplers. The measurements show that the cavity has very good damping for the higher-order modes, which was one of the main goals for the high current cavity design. 3D cavity models were simulated with Omega3P code developed by SLAC to compare with the measurements. The paper describes the cavity design, RF measurement setups and results for the copper prototype. The progress with the niobium cavity fabrication will also be described.

  10. Comparison of Measured and Calculated Coupling between a Waveguide and an RF Cavity Using CST Microwave Studio

    Energy Technology Data Exchange (ETDEWEB)

    J. Shi; H. Chen; S. Zheng; D. Li; R.A. Rimmer; H. Wang

    2006-06-26

    Accurate predications of RF coupling between an RF cavity and ports attached to it have been an important study subject for years for RF coupler and higher order modes (HOM) damping design. We report recent progress and a method on the RF coupling simulations between waveguide ports and RF cavities using CST Microwave Studio in time domain (Transit Solver). Comparisons of the measured and calculated couplings are presented. The simulated couplings and frequencies agree within {approx} 10% and {approx} 0.1% with the measurements, respectively. We have simulated couplings with external Qs ranging from {approx} 100 to {approx} 100,000, and confirmed with measurements. The method should also work well for higher Qs, and can be easily applied in RF power coupler designs and HOM damping for normal-conducting and superconducting cavities.

  11. Comparison of Measured and Calculated Coupling between a Waveguide and an RF Cavity Using CST Microwave Studio

    International Nuclear Information System (INIS)

    J. Shi; H. Chen; S. Zheng; D. Li; R.A. Rimmer; H. Wang

    2006-01-01

    Accurate predications of RF coupling between an RF cavity and ports attached to it have been an important study subject for years for RF coupler and higher order modes (HOM) damping design. We report recent progress and a method on the RF coupling simulations between waveguide ports and RF cavities using CST Microwave Studio in time domain (Transit Solver). Comparisons of the measured and calculated couplings are presented. The simulated couplings and frequencies agree within ∼ 10% and ∼ 0.1% with the measurements, respectively. We have simulated couplings with external Qs ranging from ∼ 100 to ∼ 100,000, and confirmed with measurements. The method should also work well for higher Qs, and can be easily applied in RF power coupler designs and HOM damping for normal-conducting and superconducting cavities

  12. Strategies for waveguide coupling for SRF cavities

    International Nuclear Information System (INIS)

    Doolittle, L.R.

    1998-01-01

    Despite widespread use of coaxial couplers in SRF cavities, a single, simple waveguide coupling can be used both to transmit generator power to a cavity, and to remove a large class of Higher Order Modes (HOMs, produced by the beam). There are balances and tradeoffs to be made, such as the coupling strength of the various frequencies, the transverse component of the coupler fields on the beam axis, and the magnitude of the surface fields and currents. This paper describes those design constraints, categories of solutions, and examples from the CEBAF Energy Upgrade studies

  13. Multipacting study of the RF window at the Advanced Photon Source (APS)

    International Nuclear Information System (INIS)

    Song, J. J.

    1999-01-01

    Multipacting current can cause breakdowns in high power rf components such as input couplers, waveguide windows, and higher-order mode (HOM) dampers. To understand and prevent the loss of a ceramic window or an input coupler in the Advanced Photon Source (APS) storage ring rf cavity, the multipacting phenomenon is being investigated experimentally. This paper begins with a description of simple model, presents a hardware design, and concludes with measurement of multipacting. Multipacting is explored in conjunction with conditioning the cavities and interaction with the stored beam

  14. Design optimization of the distributed modal filtering rod fiber for increasing single mode bandwidth

    DEFF Research Database (Denmark)

    Jørgensen, Mette Marie; Petersen, Sidsel Rübner; Laurila, Marko

    2012-01-01

    . Large preform tolerances are compensated during the fiber draw resulting in ultra low NA fibers with very large cores. In this paper, design optimization of the SM bandwidth of the DMF rod fiber is presented. Analysis of band gap properties results in a fourfold increase of the SM bandwidth compared...... LMA fiber amplifiers having high pump absorption through a pump cladding that is decoupled from the outer fiber. However, achieving ultra low NA for single-mode (SM) guidance is challenging, and thus different design strategies must be applied to filter out higher order modes (HOMs). The novel...... distributed modal filtering (DMF) design presented here enables SM guidance, and previous results have shown a SM mode field diameter of 60 μm operating in a 20 nm SM bandwidth. The DMF rod fiber has high index ring-shaped inclusions acting as resonators enabling SM guidance through modal filtering of HOMs...

  15. Seasonal biodiversity of black flies (Diptera: Simuliidae) and evaluation of ecological factors influencing species distribution at Doi Pha Hom Pok National Park, Thailand.

    Science.gov (United States)

    Srisuka, Wichai; Takaoka, Hiroyuki; Otsuka, Yasushi; Fukuda, Masako; Thongsahuan, Sorawat; Taai, Kritsana; Choochote, Wej; Saeung, Atiporn

    2015-09-01

    This is the first study on the seasonal biodiversity of black flies and evaluation of ecological factors influencing their distribution at Doi Pha Hom Pok National Park, northern Thailand. Larvae were collected from six fixed-stream sites in relation to altitude gradients from May 2011 to April 2013. The water temperature, water pH, conductivity, total dissolved solids (TDS), salt, water velocity, stream width and depth, streambed particle sizes, riparian vegetation, and canopy cover were recorded from each site. Monthly collections from the six sites yielded 5475 last-instar larvae, belonging to 29 black fly species. The most frequently found species from all sites were Simulium asakoae (100%) followed by Simulium yuphae (83.3%), and Simulium chiangdaoense, Simulium gombakense, Simulium phahompokense, Simulium fruticosum, Simulium maeaiense and Simulium fenestratum (66.6%). Of the 5475 last-instar larvae, S. maeaiense (19.3%), S. chiangdaoense (15.8%) and S. asakoae (14.8%), were the three most abundant species. The Shannon diversity index (H) at the six sites with different altitudes of 2100m, 2000m, 1500m, 1400m, 700m, and 500m above mean sea level, were 2.042, 1.832, 2.158, 2.123, 1.821 and 1.822, respectively. The Shannon index and number of taxa in the cold season were higher than those in the rainy and hot seasons. Principal component analysis (PCA) indicated that at least three principal components have eigen values >1.0 and accounted for 93.5% of the total variability of ecological factors among sampling sites. The Canonical correspondence analyses (CCA) showed that most species had a trend towards altitude, canopy cover, riparian vegetation and water velocity. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  16. Development of an optical resonator with high-efficient output coupler for the JAERI far-infrared free-electron laser

    International Nuclear Information System (INIS)

    Nagai, Ryoji; Hajima, Ryoichi; Nishimori, Nobuyuki; Sawamura, Masaru; Kikuzawa, Nobuhiro; Shizuma, Toshiyuki; Minehara, Eisuke

    2001-01-01

    An optical resonator with a high-efficient output coupler was developed for the JAERI far-infrared free-electron laser. The optical resonator is symmetrical near-concentric geometry with an insertable scraper output coupler. As a result of the development of the optical resonator, the JAERI-FEL has been successfully, lased with averaged power over 1 kW. Performance of the optical resonator with the output coupler was evaluated at optical wavelength of 22 μm by using an optical mode calculation code. The output coupling and diffractive loss with a dominant eigen-mode of the resonator were calculated using an iterative computation called Fox-Li procedure. An efficiency factor of the optical resonator was introduced for the evaluation of the optical resonator performance. The efficiency factor was derived by the amount of the output coupling and diffractive loss of the optical resonator. It was found that the optical resonator with the insertable scraper coupler was the most suitable to a high-power and high-efficient far-infrared free-electron laser. (author)

  17. Homeopathy for Depression - DEP-HOM: study protocol for a randomized, partially double-blind, placebo controlled, four armed study

    Science.gov (United States)

    2011-01-01

    Background Homeopathy is often sought by patients with depression. In classical homeopathy, the treatment consists of two main elements: the case history and the prescription of an individually selected homeopathic remedy. Previous data suggest that individualized homeopathic Q-potencies were not inferior to the antidepressant fluoxetine in a sample of patients with moderate to severe depression. However, the question remains whether individualized homeopathic Q-potencies and/or the type of the homeopathic case history have a specific therapeutical effect in acute depression as this has not yet been investigated. The study aims to assess the two components of individualized homeopathic treatment for acute depression, i.e., to investigate the specific effect of individualized Q-potencies versus placebo and to investigate the effect of different approaches to the homeopathic case history. Methods/Design A randomized, partially double-blind, placebo-controlled, four-armed trial using a 2 × 2 factorial design with a six-week study duration per patient will be performed. 228 patients diagnosed with major depression (moderate episode) by a psychiatrist will be included. The primary endpoint is the total score on the 17-item Hamilton Depression Rating Scale after six weeks. Secondary end points are: Hamilton Depression Rating Scale total score after two and four weeks; response and remission rates, Beck Depression inventory total score, quality of life and safety at two, four and six weeks. Statistical analyses will be by intention-to-treat. The main endpoint will be analysed by a two-factorial analysis of covariance. Within this model generalized estimation equations will be used to estimate differences between verum and placebo, and between both types of case history. Discussion For the first time this study evaluates both the specific effect of homeopathic medicines and of a homeopathic case taking in patients with depression. It is an attempt to deal with the

  18. A universal Model-R Coupler to facilitate the use of R functions for model calibration and analysis

    Science.gov (United States)

    Wu, Yiping; Liu, Shuguang; Yan, Wende

    2014-01-01

    Mathematical models are useful in various fields of science and engineering. However, it is a challenge to make a model utilize the open and growing functions (e.g., model inversion) on the R platform due to the requirement of accessing and revising the model's source code. To overcome this barrier, we developed a universal tool that aims to convert a model developed in any computer language to an R function using the template and instruction concept of the Parameter ESTimation program (PEST) and the operational structure of the R-Soil and Water Assessment Tool (R-SWAT). The developed tool (Model-R Coupler) is promising because users of any model can connect an external algorithm (written in R) with their model to implement various model behavior analyses (e.g., parameter optimization, sensitivity and uncertainty analysis, performance evaluation, and visualization) without accessing or modifying the model's source code.

  19. Improving estimations of greenhouse gas transfer velocities by atmosphere-ocean couplers in Earth-System and regional models

    Science.gov (United States)

    Vieira, V. M. N. C. S.; Sahlée, E.; Jurus, P.; Clementi, E.; Pettersson, H.; Mateus, M.

    2015-09-01

    Earth-System and regional models, forecasting climate change and its impacts, simulate atmosphere-ocean gas exchanges using classical yet too simple generalizations relying on wind speed as the sole mediator while neglecting factors as sea-surface agitation, atmospheric stability, current drag with the bottom, rain and surfactants. These were proved fundamental for accurate estimates, particularly in the coastal ocean, where a significant part of the atmosphere-ocean greenhouse gas exchanges occurs. We include several of these factors in a customizable algorithm proposed for the basis of novel couplers of the atmospheric and oceanographic model components. We tested performances with measured and simulated data from the European coastal ocean, having found our algorithm to forecast greenhouse gas exchanges largely different from the forecasted by the generalization currently in use. Our algorithm allows calculus vectorization and parallel processing, improving computational speed roughly 12× in a single cpu core, an essential feature for Earth-System models applications.

  20. Multi-planar amorphous silicon photonics with compact interplanar couplers, cross talk mitigation, and low crossing loss

    Directory of Open Access Journals (Sweden)

    Jeff Chiles

    2017-11-01

    Full Text Available We propose and experimentally demonstrate a photonic routing architecture that can efficiently utilize the space of multi-plane (3D photonic integration. A wafer with three planes of amorphous silicon waveguides was fabricated and characterized, demonstrating < 3 × 1 0 − 4 dB loss per out-of-plane waveguide crossing, 0.05 ± 0.02 dB per interplane coupler, and microring resonators on three planes with a quality factors up to 8.2 × 1 0 4 . We also explore a phase velocity mapping strategy to mitigate the cross talk between co-propagating waveguides on different planes. These results expand the utility of 3D photonic integration for applications such as optical interconnects, neuromorphic computing and optical phased arrays.

  1. OBLIMAP 2.0: a fast climate model-ice sheet model coupler including online embeddable mapping routines

    Science.gov (United States)

    Reerink, Thomas J.; van de Berg, Willem Jan; van de Wal, Roderik S. W.

    2016-11-01

    This paper accompanies the second OBLIMAP open-source release. The package is developed to map climate fields between a general circulation model (GCM) and an ice sheet model (ISM) in both directions by using optimal aligned oblique projections, which minimize distortions. The curvature of the surfaces of the GCM and ISM grid differ, both grids may be irregularly spaced and the ratio of the grids is allowed to differ largely. OBLIMAP's stand-alone version is able to map data sets that differ in various aspects on the same ISM grid. Each grid may either coincide with the surface of a sphere, an ellipsoid or a flat plane, while the grid types might differ. Re-projection of, for example, ISM data sets is also facilitated. This is demonstrated by relevant applications concerning the major ice caps. As the stand-alone version also applies to the reverse mapping direction, it can be used as an offline coupler. Furthermore, OBLIMAP 2.0 is an embeddable GCM-ISM coupler, suited for high-frequency online coupled experiments. A new fast scan method is presented for structured grids as an alternative for the former time-consuming grid search strategy, realising a performance gain of several orders of magnitude and enabling the mapping of high-resolution data sets with a much larger number of grid nodes. Further, a highly flexible masked mapping option is added. The limitation of the fast scan method with respect to unstructured and adaptive grids is discussed together with a possible future parallel Message Passing Interface (MPI) implementation.

  2. OBLIMAP 2.0: a fast climate model–ice sheet model coupler including online embeddable mapping routines

    Directory of Open Access Journals (Sweden)

    T. J. Reerink

    2016-11-01

    Full Text Available This paper accompanies the second OBLIMAP open-source release. The package is developed to map climate fields between a general circulation model (GCM and an ice sheet model (ISM in both directions by using optimal aligned oblique projections, which minimize distortions. The curvature of the surfaces of the GCM and ISM grid differ, both grids may be irregularly spaced and the ratio of the grids is allowed to differ largely. OBLIMAP's stand-alone version is able to map data sets that differ in various aspects on the same ISM grid. Each grid may either coincide with the surface of a sphere, an ellipsoid or a flat plane, while the grid types might differ. Re-projection of, for example, ISM data sets is also facilitated. This is demonstrated by relevant applications concerning the major ice caps. As the stand-alone version also applies to the reverse mapping direction, it can be used as an offline coupler. Furthermore, OBLIMAP 2.0 is an embeddable GCM–ISM coupler, suited for high-frequency online coupled experiments. A new fast scan method is presented for structured grids as an alternative for the former time-consuming grid search strategy, realising a performance gain of several orders of magnitude and enabling the mapping of high-resolution data sets with a much larger number of grid nodes. Further, a highly flexible masked mapping option is added. The limitation of the fast scan method with respect to unstructured and adaptive grids is discussed together with a possible future parallel Message Passing Interface (MPI implementation.

  3. Resonance Excitation of Longitudinal High Order Modes in Project X Linac

    Energy Technology Data Exchange (ETDEWEB)

    Khabiboulline, T.N.; Sukhanov, A.AUTHOR = Awida, M.; Gonin, I.; Lunin, A.AUTHOR = Solyak, N.; Yakovlev, V.; /Fermilab

    2012-05-01

    Results of simulation of power loss due to excitation of longitudinal high order modes (HOMs) in the accelerating superconducting RF system of CW linac of Project X are presented. Beam structures corresponding to the various modes of Project X operation are considered: CW regime for 3 GeV physics program; pulsed mode for neutrino experiments; and pulsed regime, when Project X linac operates as a driver for Neutrino Factory/Muon Collider. Power loss and associated heat load due to resonance excitation of longitudinal HOMs are shown to be small in all modes of operation. Conclusion is made that HOM couplers can be removed from the design of superconducting RF cavities of Project X linac.

  4. Resonance Excitation of Longitudinal High Order Modes in Project X Linac

    International Nuclear Information System (INIS)

    Gonin, I.V.; Khabiboulline, T.N.; Lunin, A.; Solyak, N.; Sukhanov, A.I.; Yakovlev, V.P.; Awida, M.H.

    2012-01-01

    Results of simulation of power loss due to excitation of longitudinal high order modes (HOMs) in the accelerating superconducting RF system of CW linac of Project X are presented. Beam structures corresponding to the various modes of Project X operation are considered: CW regime for 3 GeV physics program; pulsed mode for neutrino experiments; and pulsed regime, when Project X linac operates as a driver for Neutrino Factory/Muon Collider. Power loss and associated heat load due to resonance excitation of longitudinal HOMs are shown to be small in all modes of operation. Conclusion is made that HOM couplers can be removed from the design of superconducting RF cavities of Project X linac.

  5. Unstable Resonator Retrofitted Handheld Laser Designator

    Science.gov (United States)

    1978-06-01

    retrofitted with a negative-branch unstable resona- tor laser and hybrid pump cavity in place of the conventional plane-mirror/ porro prism resonator and...directed by prism B to an expanding telescope, shared with the viewing system of the designator. The actual, unfolded resonator length is approxi...was performed based on using a plane- parallel cavity consisting of a 47% reflectivity output coupler, porro - prism reflector, and the same LiNb03

  6. Paleodemografía y biología de los homínidos del Pleistoceno Medio de Europa. El caso de la Sima de los Huesos de Atapuerca

    Directory of Open Access Journals (Sweden)

    Bermúdez de Castro, José María

    1998-12-01

    Full Text Available Not available.Las excavaciones sistemáticas realizadas hasta la campaña de 1997 en el yacimiento de la Sima de los Huesos (SH de la Sierra de Atapuerca (Burgos ha proporcionado un excepcional conjunto de más de 2000 restos fósiles humanos pertenecientes a un número mínimo (NMI de 32 individuos. Las características del yacimiento de SH y el estudio tafonómico del registro sugieren un origen antrópico para la acumulación de los homínidos. Sin embargo, la discusión sobre el modelo que se ajusta a la distribución de mortalidad observada, catastrófico vs. atricional, está siendo muy fructífera para las investigaciones sobre ciertas características biológicas de la especie, Homo heidelbergensis, a la que pertenecen los homínidos de SH.

  7. High order modes in Project-X linac

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, A., E-mail: ais@fnal.gov; Lunin, A.; Yakovlev, V.; Awida, M.; Champion, M.; Ginsburg, C.; Gonin, I.; Grimm, C.; Khabiboulline, T.; Nicol, T.; Orlov, Yu.; Saini, A.; Sergatskov, D.; Solyak, N.; Vostrikov, A.

    2014-01-11

    Project-X, a multi-MW proton source, is now under development at Fermilab. In this paper we present study of high order modes (HOM) excited in continues-wave (CW) superconducting linac of Project-X. We investigate effects of cryogenic losses caused by HOMs and influence of HOMs on beam dynamics. We find that these effects are small. We conclude that HOM couplers/dampers are not needed in the Project-X SC RF cavities.

  8. Superconducting Super Collider Laboratory coupled-cavity linac mechanical design

    International Nuclear Information System (INIS)

    Starling, W.J.; Cain, T.

    1992-01-01

    A collaboration between the Superconducting Super Collider Laboratory (SSCL) and the Los Alamos National Laboratory (LANL) for the engineering and mechanical design of the SSCL Coupled-Cavity Linac (CCL) has yielded an innovative example of the well known side coupled-cavity type of linear accelerator. The SSCL CCL accelerates an H - beam from 70 MeV to 600 MeV with an rf cavity structure consisting of eight tanks in each of nine modules for a total length of about 112 meters. Magnetically-coupled bridge couplers transfer power from tank to tank within a module. A single rf power input is located at the center bridge coupler of each module. The bridge couplers permit placement along the beam line of combined function focusing/steering electromagnets and diagnostic pods for beam instrumentation. Each tank and bridge coupler is rf frequency stabilized, nominally to 1,283 MHz, by water pumped through integral water passages. Air isolation grooves surround the water passages at each braze joint so that water-to-vacuum interfaces are avoided. Each tank is supported by adjustable spherical bearing rod end struts to permit alignment and accommodate thermal expansion and contraction of the rf structure. Tank struts, electromagnet/diagnostic pod support frames, vacuum manifolds and utilities are all mounted to a girder-and-leg support stand running the full length of the CCL. (Author) tab., fig

  9. Design of an amplifier model accounting for thermal effect in fully aperiodic large pitch fibers

    Science.gov (United States)

    Tragni, K.; Molardi, C.; Poli, F.; Dauliat, R.; Leconte, B.; Darwich, D.; du Jeu, R.; Malleville, M. A.; Jamier, R.; Selleri, S.; Roy, P.; Cucinotta, A.

    2018-02-01

    Yb-doped Photonic Crystal Fibers (PCFs) have triggered a significant power scaling into fiber-based lasers. However thermally-induced effects, like mode instability, can compromise the output beam quality. PCF design with improved Higher Order Mode (HOM) delocalization and effective thermal resilience can contain the problem. In particular, Fully- Aperiodic Large-Pitch Fibers (FA-LPFs) have shown interesting properties in terms of resilience to thermal effects. In this paper the performances of a Yb-doped FA-LPF amplifier are experimentally and numerically investigated. Modal properties and gain competition between Fundamental Mode (FM) and first HOM have been calculated, in presence of thermal effects. The main doped fiber characteristics have been derived by comparison between experimental and numerical results.

  10. Conceptual design of a high real-estate gradient cavity for a SRF ERL

    International Nuclear Information System (INIS)

    Xu, Chen; Stony Brook University, NY; Ben-Zvi, Ilan; Stony Brook University, NY; Hao, Yue

    2017-01-01

    The term “real-estate gradient” is used to describe the energy gain provided by an accelerating structure per actual length it takes in the accelerator. given that the length of the tunnel available for the accelerator is constrained, the real-estate gradient is an important measure of the efficiency of a given accelerator structure. When designing an accelerating cavity to be efficient in this sense, the unwanted Higher Order Mode (HOM) fields should be reduced by suitable HOM dampers. This is a particularly important consideration for high current operation. The additional RF components might take longitude space and reduce the total accelerating efficiency. We describe a new high efficiency 5-cell cavity with the dampers included. The total length of the cavity is reduced by 13% as compared to a more conventional design without compromising the cavity fundamental-mode performance. In addition, the HOM impedance is reduced for a higher Beam-Break-Up (BBU) threshold of operating current. In this article, we consider an example, a possible application at the eRHIC Energy Recovery Linac (ERL).

  11. Conceptual design of a high real-estate gradient cavity for a SRF ERL

    Science.gov (United States)

    Xu, Chen; Ben-Zvi, Ilan; Hao, Yue; Xin, Tianmu; Wang, Haipeng

    2017-10-01

    The term "real-estate gradient" is used to describe the energy gain provided by an accelerating structure per actual length it takes in the accelerator. given that the length of the tunnel available for the accelerator is constrained, the real-estate gradient is an important measure of the efficiency of a given accelerator structure. When designing an accelerating cavity to be efficient in this sense, the unwanted Higher Order Mode (HOM) fields should be reduced by suitable HOM dampers. This is a particularly important consideration for high current operation. The additional RF components might take longitude space and reduce the total accelerating efficiency. We describe a new high efficiency 5-cell cavity with the dampers included. The total length of the cavity is reduced by 13% as compared to a more conventional design without compromising the cavity fundamental-mode performance. In addition, the HOM impedance is reduced for a higher Beam-Break-Up (BBU) threshold of operating current. In this paper, we consider an example, a possible application at the eRHIC Energy Recovery Linac (ERL).

  12. On the photonic implementation of universal quantum gates, bell states preparation circuit and quantum LDPC encoders and decoders based on directional couplers and HNLF.

    Science.gov (United States)

    Djordjevic, Ivan B

    2010-04-12

    The Bell states preparation circuit is a basic circuit required in quantum teleportation. We describe how to implement it in all-fiber technology. The basic building blocks for its implementation are directional couplers and highly nonlinear optical fiber (HNLF). Because the quantum information processing is based on delicate superposition states, it is sensitive to quantum errors. In order to enable fault-tolerant quantum computing the use of quantum error correction is unavoidable. We show how to implement in all-fiber technology encoders and decoders for sparse-graph quantum codes, and provide an illustrative example to demonstrate this implementation. We also show that arbitrary set of universal quantum gates can be implemented based on directional couplers and HNLFs.

  13. Design and Realization Aspects of 1-THz Cascade Backward Wave Amplifier Based on Double Corrugated Waveguide

    DEFF Research Database (Denmark)

    Paoloni, Claudio; Di Carlo, Aldo; Bouamrane, Fayçal

    2013-01-01

    The design and fabrication challenges in the first ever attempt to realize a 1-THz vacuum tube amplifier are described. Implementation of innovative solutions including a slow-wave structure in the form of a double corrugated waveguide, lateral tapered input and output couplers, deep X-ray LIGA f...

  14. Design

    DEFF Research Database (Denmark)

    Volf, Mette

    This publication is unique in its demystification and operationalization of the complex and elusive nature of the design process. The publication portrays the designer’s daily work and the creative process, which the designer is a part of. Apart from displaying the designer’s work methods...... and design parameters, the publication shows examples from renowned Danish design firms. Through these examples the reader gets an insight into the designer’s reality....

  15. Tunable negative-tap photonic microwave filter based on a cladding-mode coupler and an optically injected laser of large detuning.

    Science.gov (United States)

    Chan, Sze-Chun; Liu, Qing; Wang, Zhu; Chiang, Kin Seng

    2011-06-20

    A tunable negative-tap photonic microwave filter using a cladding-mode coupler together with optical injection locking of large wavelength detuning is demonstrated. Continuous and precise tunability of the filter is realized by physically sliding a pair of bare fibers inside the cladding-mode coupler. Signal inversion for the negative tap is achieved by optical injection locking of a single-mode semiconductor laser. To couple light into and out of the cladding-mode coupler, a pair of matching long-period fiber gratings is employed. The large bandwidth of the gratings requires injection locking of an exceptionally large wavelength detuning that has never been demonstrated before. Experimentally, injection locking with wavelength detuning as large as 27 nm was achieved, which corresponded to locking the 36-th side mode. Microwave filtering with a free-spectral range tunable from 88.6 MHz to 1.57 GHz and a notch depth larger than 35 dB was obtained.

  16. Quantum Statistical Properties of the Codirectional Kerr Nonlinear Coupler in Terms of su (2 ) Lie Group in Interaction with a Two-level Atom

    Science.gov (United States)

    Abdalla, M. Sebawe; Khalil, E. M.; Obada, A. S.-F.

    2017-08-01

    The problem of the codirectional Kerr coupler has been considered several times from different point of view. In the present paper we introduce the interaction between a two-level atom and the codirectional Kerr nonlinear coupler in terms of su (2 ) Lie algebra. Under certain conditions we have adjusted the Kerr coupler and consequently we have managed to handle the problem. The wave function is obtained by using the evolution operator where the Heisnberg equation of motion is invoked to get the constants of the motion. We note that the Kerr parameter χ as well as the quantum number j plays the role of controlling the atomic inversion behavior. Also the maximum entanglement occurs after a short period of time when χ = 0. On the other hand for the entropy and the variance squeezing we observe that there is exchange between the quadrature variances. Furthermore, the variation in the quantum number j as well as in the parameter χ leads to increase or decrease in the number of fluctuations. Finally we examined the second order correlation function where classical and nonclassical phenomena are observed.

  17. Development and performance of a new version of the OASIS coupler, OASIS3-MCT_3.0

    Directory of Open Access Journals (Sweden)

    A. Craig

    2017-09-01

    Full Text Available OASIS is coupling software developed primarily for use in the climate community. It provides the ability to couple different models with low implementation and performance overhead. OASIS3-MCT is the latest version of OASIS. It includes several improvements compared to OASIS3, including elimination of a separate hub coupler process, parallelization of the coupling communication and run-time grid interpolation, and the ability to easily reuse mapping weight files. OASIS3-MCT_3.0 is the latest release and includes the ability to couple between components running sequentially on the same set of tasks as well as to couple within a single component between different grids or decompositions such as physics, dynamics, and I/O. OASIS3-MCT has been tested with different configurations on up to 32 000 processes, with components running on high-resolution grids with up to 1.5 million grid cells, and with over 10 000 2-D coupling fields. Several new features will be available in OASIS3-MCT_4.0, and some of those are also described.

  18. Development and performance of a new version of the OASIS coupler, OASIS3-MCT_3.0

    Science.gov (United States)

    Craig, Anthony; Valcke, Sophie; Coquart, Laure

    2017-09-01

    OASIS is coupling software developed primarily for use in the climate community. It provides the ability to couple different models with low implementation and performance overhead. OASIS3-MCT is the latest version of OASIS. It includes several improvements compared to OASIS3, including elimination of a separate hub coupler process, parallelization of the coupling communication and run-time grid interpolation, and the ability to easily reuse mapping weight files. OASIS3-MCT_3.0 is the latest release and includes the ability to couple between components running sequentially on the same set of tasks as well as to couple within a single component between different grids or decompositions such as physics, dynamics, and I/O. OASIS3-MCT has been tested with different configurations on up to 32 000 processes, with components running on high-resolution grids with up to 1.5 million grid cells, and with over 10 000 2-D coupling fields. Several new features will be available in OASIS3-MCT_4.0, and some of those are also described.

  19. All-fiber optical mode switching based on cascaded mode selective couplers for short-reach MDM networks

    Science.gov (United States)

    Ren, Fang; Li, Juhao; Wu, Zhongying; Yu, Jinyi; Mo, Qi; Wang, Jianping; He, Yongqi; Chen, Zhangyuan; Li, Zhengbin

    2017-04-01

    We propose and experimentally demonstrate an all-fiber optical mode switching structure supporting independent switching, exchanging, adding, and dropping functionalities in which each mode can be switched individually. The mode switching structure consists of cascaded mode selective couplers (MSCs) capable of exciting and selecting specific higher order modes in few-mode fibers with high efficiency and one multiport optical switch routing the independent spatial modes to their destinations. The data carried on three different spatial modes can be switched, exchanged, added, and dropped through this all-fiber structure. For this experimental demonstration, optical on-off-keying (OOK) signals at 10-Gb/s carried on three spatial modes are successfully processed with open and clear eye diagrams. The mode switch exhibits power penalties of less than 3.1 dB after through operation, less than 2.7 dB after exchange operation, less than 2.8 dB after switching operation, and less than 1.6 dB after mode adding and dropping operations at the bit-error rate (BER) of 10-3, while all three channels carried on three spatial modes are simultaneously routed. The proposed structure, compatible with current optical switching networks based on single-mode fibers, can potentially be used to expand the switching scalability in advanced and flexible short-reach mode-division multiplexing-based networks.

  20. Effects of tubing length and coupling method on hearing threshold and real-ear to coupler difference measures.

    Science.gov (United States)

    Gustafson, Samantha; Pittman, Andrea; Fanning, Robert

    2013-06-01

    This tutorial demonstrates the effects of tubing length and coupling type (i.e., foam tip or personal earmold) on hearing threshold and real-ear-to-coupler difference (RECD) measures. Hearing thresholds from 0.25 kHz through 8 kHz are reported at various tubing lengths for 28 normal-hearing adults between the ages of 22 and 31 years. RECD values are reported for 14 of the adults. All measures were made with an insert earphone coupled to a standard foam tip and with an insert earphone coupled to each participant's personal earmold. Threshold and RECD measures obtained with a personal earmold were significantly different from those obtained with a foam tip on repeated measures analyses of variance. One-sample t tests showed these differences to vary systematically with increasing tubing length, with the largest average differences (7-8 dB) occurring at 4 kHz. This systematic examination demonstrates the equal and opposite effects of tubing length on threshold and acoustic measures. Specifically, as tubing length increased, sound pressure level in the ear canal decreased, affecting both hearing thresholds and the real-ear portion of the RECDs. This demonstration shows that when the same coupling method is used to obtain the hearing thresholds and RECD, equal and accurate estimates of real-ear sound pressure level are obtained.

  1. A Novel Wind Turbine Concept Based on an Electromagnetic Coupler and the Study of Its Fault Ride-through Capability

    Directory of Open Access Journals (Sweden)

    Rui You

    2013-11-01

    Full Text Available This paper presents a novel type of variable speed wind turbine with a new drive train different from the variable speed wind turbine commonly used nowadays. In this concept, a synchronous generator is directly coupled with the grid, therefore, the wind turbine transient overload capability and grid voltage support capability can be significantly improved. An electromagnetic coupling speed regulating device (EMCD is used to connect the gearbox high speed shaft and synchronous generator rotor shaft, transmitting torque to the synchronous generator, while decoupling the gearbox side and the synchronous generator, so the synchronous generator torque oscillations during a grid fault are not transmitted to the gearbox. The EMCD is composed of an electromagnetic coupler and a one quadrant operation converter with reduced capability and low cost. A control strategy for the new wind turbine is proposed and a 2 MW wind turbine model is built to study the wind turbine fault ride-through capability. An integrated simulation environment based on the aeroelastic code HAWC2 and software Matlab/Simulink is used to study its fault ride-through capability and the impact on the structural loads during grid three phase and two phase short circuit faults.

  2. L'evolució del rol dramàtic de la Bella Dorment i Malèfica a les adaptacions cinematogràfiques homònimes de 1959 i 2014

    OpenAIRE

    Escobar Pérez, Marina

    2015-01-01

    Aquest treball de recerca i investigació és el resultat d'un anàlisi qualitatiu i de gènere realitzat d'acord amb la teoria audiovisual narrativa i la teoria fílmica feminista sobre la representació cinematogràfica dels personatges de la Bella Dorment i Malèfica a les pel•lícules homònimes dels anys 1959 i 2014 amb l'objectiu de determinar l'evolució del seu rol dramàtic. Este trabajo de investigación es el resultado de un análisis cualitativo y de género realizado en base a la teoría audi...

  3. Design and RF Test of Broadband Coaxial Hybrid Splitter for ITER ICRF System

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H. J.; Wang, S. J.; Park, B. H.; Yang, H. L.; Kwak, J. G. [National Fusion Research Institute, Daejeon (Korea, Republic of); Choi, J. J. [Kwangwoon Univ., Seoul (Korea, Republic of)

    2013-10-15

    The ICRF system of the ITER is required to couple 20 MW to the plasma in the 40∼55 MHz frequency band for RF heating and current drive operation. The corresponding matching system of ICRF antenna must be load-resilient for a wide range of antenna load variations due to mode transitions or edge localized modes. Indeed the use of hybrid splitters ensures that no reflections occur at the generator when the reflections on the adjacent lines are equal both in magnitude and in phase, in which case all reflected power will not be seen by the generators and will be returned to the dummy loads. Most 3 dB coaxial hybrid circuits installed and implemented on the ICRF system is single section coupler providing best performance at the design frequency with narrow bandwidth. The bandwidth of such a single-section 3 dB hybrid coupler is limited to less than 20% due to the quarter wavelength transmission line requirement. The amplitude balance becomes rapidly degraded away from the center frequency. We designed, fabricated and tested a high power, ultra-wideband two-section 3 dB coaxial hybrid coupler over all frequencies from 40 MHz to 55 MHz for ITER ICRF system by configuring asymmetric impedance matching. We have designed, fabricated, and tested a 3-dB wideband hybrid coupler for stable and load resilient operation of the ITER ICRF system. The wideband two section 3-dB coaxial hybrid coupler was well designed by configuring asymmetric impedance matching using HFSS. In the rf measurements, we found that wideband hybrid splitter has an amplitude imbalance of 0.1 dB over all frequencies from 40 MHz to 55 MHz. We expect that wideband hybrid splitter will be applicable to ITER ICRF matching system for load resilient operation at fusion plasmas.

  4. Design

    DEFF Research Database (Denmark)

    Volf, Mette

    Design - proces & metode iBog®  er enestående i sit fokus på afmystificering og operationalisering af designprocessens flygtige og komplekse karakter. Udgivelsen går bag om designerens daglige arbejde og giver et indblik i den kreative skabelsesproces, som designeren er en del af. Udover et bredt...... indblik i designerens arbejdsmetoder og designparametre giver Design - proces & metode en række eksempler fra anerkendte designvirksomheder, der gør det muligt at komme helt tæt på designerens virkelighed....

  5. Design

    Science.gov (United States)

    Buchanan, Richard; Cross, Nigel; Durling, David; Nelson, Harold; Owen, Charles; Valtonen, Anna; Boling, Elizabeth; Gibbons, Andrew; Visscher-Voerman, Irene

    2013-01-01

    Scholars representing the field of design were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Richard Buchanan, Nigel Cross, David Durling, Harold Nelson, Charles Owen, and Anna Valtonen. Scholars…

  6. Design of a high-power test model of the PEP-II rf cavity

    International Nuclear Information System (INIS)

    Schwarz, H.D.; Bell, R.A.; Hodgson, J.A.

    1993-05-01

    The design of a normal-conducting high-power test cavity (HPTC) for PEP-II is described. The cavity includes HOM loading waveguides and provisions for testing two alternate input coupling schemes. 3-D electromagnetic field simulations provided input information for the surface power deposition. Finite element codes were utilized for thermal and stress analyses of the cavity to arrive at a suitable mechanical design capable of handling the high power dissipation. The mechanical design approach with emphasis on the cooling channel layout and mechanical stress reduction is described

  7. Distributed Weak Fiber Bragg Grating Vibration Sensing System Based on 3 × 3 Fiber Coupler

    Science.gov (United States)

    Li, Wei; Zhang, Jian

    2018-06-01

    A novel distributed weak fiber Bragg gratings (FBGs) vibration sensing system has been designed to overcome the disadvantages of the conventional methods for optical fiber sensing networking, which are: low signal intensity in the usually adopted time-division multiplexing (TDM) technology, insufficient quantity of multiplexed FBGs in the wavelength-division multiplexing (WDM) technology, and that the mixed WDM/TDM technology measures only the physical parameters of the FBG locations but cannot perform distributed measurement over the whole optical fiber. This novel system determines vibration events in the optical fiber line according to the intensity variation of the interference signals between the adjacent weak FBG reflected signals and locates the vibration points accurately using the TDM technology. It has been proven by tests that this system performs vibration signal detection and demodulation in a way more convenient than the conventional methods for the optical fiber sensing system. It also measures over the whole optical fiber, therefore, distributed measurement is fulfilled, and the system locating accuracy is up to 20 m, capable of detecting any signals of whose drive signals lower limit voltage is 0.2 V while the frequency range is 3 Hz‒1 000 Hz. The system has the great practical significance and application value for perimeter surveillance systems.

  8. Optimization of the microwave coupler and microwave measurements of the microtron cavity for 20 MeV pre-injector microtron for INDUS-I SRS

    International Nuclear Information System (INIS)

    Wanmode, Y.D.; Shrivastava, Purushottam; Hannurkar, P.R.

    2003-01-01

    A 20 MeV microtron was developed indigenously by CAT for pre-injection of 20 MeV electrons to the 450 MeV/700 MeV Booster Synchrotron for INDUS-I and INDUS-II Synchrotron Radiation Sources. The injector microtron uses a high Q microwave cavity for acceleration of electrons. The microwave power is fed to the microtron cavity through an iris type coupler whose dimensions are optimized for the coupling factor and resonant frequency for the accelerator. The present paper gives the procedure details for coupling factor optimization, tuning of the resonant frequency and results achieved. (author)

  9. Design

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Pettiway, Keon

    2017-01-01

    In this chapter, Ole B. Jensen takes a situational approach to mobilities to examine how ordinary life activities are structured by technology and design. Using “staging mobilities” as a theoretical approach, Jensen considers mobilities as overlapping, actions, interactions and decisions by desig...... by providing ideas about future research for investigating mobilities in situ as a kind of “staging,” which he notes is influenced by the “material turn” in social sciences....... with a brief description of how movement is studied within social sciences after the “mobilities turn” versus the idea of physical movement in transport geography and engineering. He then explains how “mobilities design” was derived from connections between traffic and architecture. Jensen concludes...

  10. Hemodilución normovolémica intencional alternativa práctica para la transfusión homóloga de sangre en cirugía general y especializada

    Directory of Open Access Journals (Sweden)

    Lázaro Manuel Fernández Suárez

    2000-08-01

    Full Text Available La hemodilución normovolémica intencional es una técnica útil que reduce los requerimientos transfusionales entre el 15 y el 40 %. Representa un ahorro de sangre homóloga, crea una reserva de sangre autógena, reduce el número de hematíes perdidos en la hemorragia quirúrgica, además mejora el flujo sanguíneo y disminuye la viscosidad de la sangre, para aumentar la oxigenación hística y reducir la posibilidad de tromboembolismo pulmonar entre otros beneficios. Se realizó un estudio prospectivo con 50 pacientes supuestamente sanos con la categoría I-II de la A.S.A. (American Society of Anesthesia sobre el uso de la hemodilución normovolémica. Se efectuó la extracción según nomograma para llevar el hematócrito a 0,25 preoperatoriamente, corroborado por la técnica de microhematócrito y controlado en el transoperatorio; no se apreció movimiento anormal en los valores del coagulograma. Se apreció un incuestionable ahorro de sangre homóloga con el consiguiente beneficio para el pacienteIntentional normovolemic hemodilution is a useful technique reducing the transfusion requirements by 15 to 40%. It represents a saving of homologous blood, creates a reserve of antigen blood, reduces the number of hematids lost in a surgical haemorrhage, improves blood flow and lower blood viscosity to increase hystic oxigenation and decrease the possibilities of pulmonar thromboembolism among other benefits. A retrospective study of 50 supposedly healthy patients with catetory I-II of ASA (American Society of Anesthesia was made on the use of normovolemic dilution. According to a nomogram, blood extraction was made to take hematocrit to 0.25 before surgery, a value that was confirmed with microhematocrit technique and intraoperative controlled. No abnormal fluctuation of coagulation test values were observed. There was an unquestionable saving of homologous blood with the corresponding benefit for the patient

  11. Experimental design rules for implementing biconically tapered single mode optical fibre displacement sensors

    Science.gov (United States)

    Arregui, Francisco J.; Matias, Ignacio R.; Bariain, Candido; Lopez-Amo, Manuel

    1998-06-01

    Tapered optical fibers are used to design couplers, wavelength division multiplexers, near field scanning optical microscopy, just to mention a few. Moreover, and due to its strong transmission dependence to external medium the tapered fiber may also be used to sense distinct parameters such as temperature, humidity, PH, etc. In this work bending effects in tapers are exploited to achieved displacement sensors and to present design rules for implementing these sensors according to the desired both range and sensitivity.

  12. Design and Development of Monolithic Microwave Integrated Amplifiers and Coupling Circuits for Telecommunication Systems Applications

    Directory of Open Access Journals (Sweden)

    R. Makri

    2002-01-01

    quadrature coupler and a Wilkinson one in order to reduce size. Finally, a two stages low noise amplifier was designed with the use of H40 GaAs process in order the differences between the relevant designs to be explored. The key specifications for this MMIC LNA include operation at 10 GHz with a total gain of 17 dB while the noise figure is less than 1.5 dB.

  13. An elastomeric grating coupler

    NARCIS (Netherlands)

    Kocabas, A.; Ay, F.; Dana, A.; Aydinli, A.

    We report on a novel nondestructive and reversible method for coupling free space light to planar optical waveguides. In this method, an elastomeric grating is used to produce an effective refractive index modulation on the surface of the optical waveguide. The external elastomeric grating binds to

  14. High-power RF cavity R ampersand D for the PEP-II B Factory

    International Nuclear Information System (INIS)

    Rimmer, R.; Lambertson, G.; Hodgson, J.

    1994-06-01

    We describe the development of a high-power test model of the 476 MHz RF cavity for the PEP-II B Factory. This cavity is designed to demonstrate the feasibility of a high-power design with higher-order mode (HOM) damping waveguides and the fabrication technologies involved, and it can also be used to evaluate aperture or loop couplers and various RF windows. Changes to the RF design to reduce peak surface heating are discussed and results of finite-element analyses of temperature and stress are presented. Fabrication methods for the prototype and subsequent production cavities are discussed

  15. Reparação do ligamento cruzado cranial de cães por tendão homólogo conservado em glicerina e associado a fio de náilon

    Directory of Open Access Journals (Sweden)

    Oliveira Simone Tostes de

    2003-01-01

    Full Text Available A ruptura do ligamento cruzado cranial (LCC é uma das patologias de maior prevalência no joelho de cães e sua correção é um problema atual. Após a ruptura experimental do LCC, em cães, implantou-se o tendão do músculo extensor longo dos dedos, homólogo, conservado em glicerina a 98%, associado ao fio de mononáilon, utilizando-se técnica intra-articular. Foram utilizados 18 cães com peso médio de 16,5kg, adultos, separados em três grupos (A, B e C e avaliados por 45, 80 e 120 dias de pós-operatório, respectivamente. Foi realizada avaliação clínica, radiográfica, macroscópica e histológica. A técnica demonstrou-se eficiente para o retorno funcional do membro promovendo estabilidade articular, apesar de o implante biológico ter sido reabsorvido na maioria dos animais, e do fio de náilon ter perdido sua tensão inicial.

  16. Design and Measurements of an X-Band Accelerating Cavity for SPARC

    CERN Document Server

    Alesini, David; Falone, Antonio; Ferrario, Massimo; Migliorati, Mauro; Mostacci, Andrea; Palpini, Federica; Palumbo, Luigi; Spataro, Bruno

    2005-01-01

    The paper presents the design of an X-band accelerating section for linearizing the longitudinal phase space in the Frascati Linac Coherent Light Source (SPARC). The structure, operating on the pi standing wave mode, is a 9 cells structure feeded by a central waveguide coupler and has been designed to obtain a 5 MV accelerating voltage. The 2D profile has been obtained using the e.m. codes SUPERFISH and OSCARD2D while the coupler has been designed using HFSS. Bead-pull measurement made on a copper prototype are illustrated and compared with the numerical results. Mechanical details of the realized prototype and RF properties of the structure as a function of the assembly characteristics are also discussed.

  17. Design and characterization of integrated components for SiN photonic quantum circuits.

    Science.gov (United States)

    Poot, Menno; Schuck, Carsten; Ma, Xiao-Song; Guo, Xiang; Tang, Hong X

    2016-04-04

    The design, fabrication, and detailed calibration of essential building blocks towards fully integrated linear-optics quantum computation are discussed. Photonic devices are made from silicon nitride rib waveguides, where measurements on ring resonators show small propagation losses. Directional couplers are designed to be insensitive to fabrication variations. Their offset and coupling lengths are measured, as well as the phase difference between the transmitted and reflected light. With careful calibrations, the insertion loss of the directional couplers is found to be small. Finally, an integrated controlled-NOT circuit is characterized by measuring the transmission through different combinations of inputs and outputs. The gate fidelity for the CNOT operation with this circuit is estimated to be 99.81% after post selection. This high fidelity is due to our robust design, good fabrication reproducibility, and extensive characterizations.

  18. Design proposal for door thresholds

    Directory of Open Access Journals (Sweden)

    Smolka Radim

    2017-01-01

    Full Text Available Panels for openings in structures have always been an essential and integral part of buildings. Their importance in terms of a building´s functionality was not recognised. However, the general view on this issue has changed from focusing on big planar segments and critical details to sub-elements of these structures. This does not only focus on the forms of connecting joints but also on the supporting systems that keep the panels in the right position and ensure they function properly. One of the most strained segments is the threshold structure, especially the entrance door threshold structure. It is the part where substantial defects in construction occur in terms of waterproofing, as well as in the static, thermal and technical functions thereof. In conventional buildings, this problem is solved by pulling the floor structure under the entrance door structure and subsequently covering it with waterproofing material. This system cannot work effectively over the long term so local defects occur. A proposal is put forward to solve this problem by installing a sub-threshold door coupler made of composite materials. The coupler is designed so that its variability complies with the required parameters for most door structures on the European market.

  19. Vertical and horizontal test results of 3.9-GHz accelerating cavities at FNAL

    Energy Technology Data Exchange (ETDEWEB)

    Khabiboulline, T.; Edwards, H.; Foley, M.; Harms, E.; Hocker, James Andrew; Mitchell, D.; Rowe, A.; Solyak, N.; /Fermilab

    2008-06-01

    The 3rd harmonic 3.9GHz accelerating cavity was proposed to improve the beam performance of the VUV FEL, FLASH. In the frame of a collaborative agreement, Fermilab will provide DESY with a cryomodule containing a string of four cavities. Seven 9-cell Nb cavities were tested and six of them did reach accelerating gradient up to 24 MV/m almost twice more than design value of 14 MV/m. Two of these cavities are with new HOM couplers with improved design. In this paper we present all results of the vertical and horizontal tests.

  20. Fabrication of low temperature cofired ceramic (LTCC) chip couplers for high frequencies : I. Effect of binder burnout process on the formation of electrode line

    Energy Technology Data Exchange (ETDEWEB)

    Cho, N.T.; Shim, K.B.; Lee, S.W. [Hanyang University, Seoul (Korea); Koo, K.D. [K-Cera Inc., Yongin (Korea)

    1999-06-01

    In the fabrication of ceramic chip couplers for high frequency applications such as the mobile communication equipment, the formation of electrode lines and Ag diffusion were investigated with heat treatment conditions for removing organic binders. The deformation and densification of the electrode line greatly depended on the binder burnout process due to the overlapped temperature zone near 400{sup o} C of the binder dissociation and the solid phase sintering of the silver electrode. Ag ions were diffused into the glass ceramic substrate. The Ag diffusion was led by the glassy phase containing Pb ions rather than by the crystalline phase containing Ca ions. The fact suggests that the Ag diffusion could be controlled by managing the composition of the glass ceramic substrate. 9 refs., 10 figs., 1 tab.

  1. The interaction between a beam and a superconducting cavity module: Measurements in CESR and CESR-Phase 3 goals

    Energy Technology Data Exchange (ETDEWEB)

    Belomestnykh, S; Flynn, G; Hartung, W; Kirchgessner, J; Moffat, D; Muller, H; Padamsee, H; Pisharody, M; Veshcherevich, V [Cornell Univ., Ithaca, NY (United States). Lab. of Nuclear Studies

    1996-08-01

    Plans for the next generation of electron-positron colliders (B-factories and B-factory-like machines) call for high beam currents to produce luminosities of the order of 10 (exp 33). To store these high currents in a machine, special attention must be paied to the interaction of the beam with discontinuities in the surrounding vacuum chamber. RF cavities are among the biggest perturbations in accelerator vacuum chambers and are therefore among the biggest sources of beam instabilities. Accelerating structures of new machines are being designed to have smaller impedance to reduce the beam-cavity interaction. Prototypes for the cavity, input coupler, cryostat, and higher-order mode (HOM) loads were subjected and are tested in CESR. A superconducting (SRF) cavity was installed in addition to the four five-cell normal conducting cavities. As a result, the calorimetry and RF power results agree with predictions up to their respective uncertainties. The results of wake potential sampling suggested that the wake fields of the SRF cavity will not limit the performance of CESR in bunch train operation. No beam instabilities or dangerous HOMs were encountered while sweeping the HOM frequencies using the cavity tuner or while exciting multipole HOMs by displacing the beam off axis. (G.K.)

  2. Progress toward NLC / GLC prototype accelerator structures

    CERN Document Server

    Wang, J W; Arkan, T; Baboi, N; Boffo, C; Bowden, G B; Burke, D L; Carter, H; Chan, J; Cornuelle, J; Döbert, Steffen; Dolgashev, Valery A; Finley, D; Gonin, I; Higashi, Y; Higo, T; Jones, R M; Khabiboulline, T; Kume, T; Lewandowski, J; Li, Z; Miller, R H; Mishra, S; Morozumi, Y; Nantista, C; Pearson, C; Romanov, G; Ruth, Ronald D; Solyak, N; Tantawi, S; Toge, N; Ueno, K; Wilson, P B; Xiao, L

    2004-01-01

    The accelerator structure groups for NLC (Next Linear Collider) and GLC (Global Linear Colliders) have successfully collaborated on the research and development of a major series of advanced accelerator structures based on room-temperature technology at X-band frequency. The progress in design, simulation, microwave measurement and high gradient tests are summarized in this paper. The recent effort in design and fabrication of the accelerator structure prototype for the main linac is presented in detail including HOM (High Order Mode) suppression and couplers, fundamental mode couplers, optimized accelerator cavities as well as plans for future structures. We emphasize techniques to reduce the field on the surface of the copper structures (in order to achieve high accelerating gradients), limit the dipole wakefields (to relax alignment tolerance and prevent a beam break up instability) and improve shunt impedance (to reduce the RF power required).

  3. RF cavity R and D at LBNL for the NLC damping rings, FY1999

    International Nuclear Information System (INIS)

    Rimmer, R.A.; Corlett, J.N.; Koehler, G.; Li, D.; Hartman, N.; Rasson, J.; Saleh, T.

    1999-01-01

    This report contains a summary of the R and D activities at LBNL on RF cavities for the NLC damping rings during fiscal year19999. These activities include the optimization of the RF design for both efficiency and damping of higher-order (HOMs), by systematic study of the cavity profile, the effect of the beam pipe diameter, nosecone angle and gap, the cross section and position of the HOM damping waveguides and the coupler. The effect of the shape of the HOM waveguides and their intersection with the cavity wall on the local surface heating is also an important factor, since it determines the highest stresses in the cavity body. This was taken into account during the optimization so that the stresses could be reduced at the same time as the HOP damping was improved over previous designs. A new method of calculating the RF heating was employed, using a recently released high frequency electromagnetic element in ANSYS. This greatly facilitates the thermal and stress analysis of the design and fabrication methods have been developed with the goals of lower stresses, fewer parts and simpler assembly compared to previous designs. This should result in substantial cost savings. Preliminary designs are described for the cavity ancillary components including the RF window, HOM loads, and tuners. A preliminary manufacturing plan is included, with an initial estimate of the resource requirements. Other cavity options are discussed which might be desirable to either lower the R/Q, for reduced transient response, or lower the residual HOM impedance to reduce coupled-bunch growth rates further still

  4. Design of a high power TM01 mode launcher optimized for manufacturing by milling

    Energy Technology Data Exchange (ETDEWEB)

    Dal Forno, Massimo [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-12-15

    Recent research on high-gradient rf acceleration found that hard metals, such as hard copper and hard copper-silver, have lower breakdown rate than soft metals. Traditional high-gradient accelerating structures are manufactured with parts joined by high-temperature brazing. The high temperature used in brazing makes the metal soft; therefore, this process cannot be used to manufacture structures out of hard metal alloys. In order to build the structure with hard metals, the components must be designed for joining without high-temperature brazing. One method is to build the accelerating structures out of two halves, and join them by using a low-temperature technique, at the symmetry plane along the beam axis. The structure has input and output rf power couplers. We use a TM01 mode launcher as a rf power coupler, which was introduced during the Next Linear Collider (NLC) work. The part of the mode launcher will be built in each half of the structure. This paper presents a novel geometry of a mode launcher, optimized for manufacturing by milling. The coupler was designed for the CERN CLIC working frequency f = 11.9942 GHz; the same geometry can be scaled to any other frequency.

  5. Superconducting Prototype Cavities for the Spallation Neutron Source (SNS) Project

    International Nuclear Information System (INIS)

    Ciovati, G.; Kneisel, P.; Brawley, J.; Bundy, R.; Campisi, I.; Davis, K.; Macha, K.; Machie, D.; Mammosser, J.; Morgan, S.; Sundelin, R.; Turlington, L.; Wilson, K.; Doleans, M.; Kim, S.H.; Barni, D.; Pagani, C.; Pierini, P.; Matsumoto, K.; Mitchell, R.; Schrage, D.; Parodi, R.; Sekutowicz, J.; Ylae-Oijala, P.

    2001-01-01

    The Spallation Neutron Source project includes a superconducting linac section in the energy range from 192 MeV to 1000 MeV, operating at a frequency of 805 MHz at 2.1 K. For this energy range two types of cavities are needed with geometrical beta - values of beta= 0.61 and beta= 0.81. An aggressive cavity prototyping program is being pursued at Jlab, which calls for fabricating and testing of four beta= 0.61 cavities and two beta= 0.81 cavities. Both types consist of six cells made from high purity niobium and feature one HOM coupler on each beam pipe and a port for a high power coaxial input coupler. Three of the four beta= 0.61 cavities will be used for a cryomodule test in early 2002. At this time four medium beta cavities and one high beta cavity have been completed at JLab. The first tests on the beta=0.61 cavity and the beta= 0.81 exceeded the design values for gradient and Q - value: E acc = 1 0.3 MV/m and Q = 5 x 10 9 at 2.1K for beta= 0.61 and E acc = 12.3 MV/m and Q = 5 x 10 9 at 2.1K for beta= 0.81. One of the medium beta cavities has been equipped with an integrated helium vessel and measurements of the static and dynamic Lorentz force detuning will be done and compared to the ''bare'' cavities. In addition two single cell cavities have been fabricated, equipped with welded-on HOM couplers. They are being used to evaluate the HOM couplers with respect to multipacting, fundamental mode rejection and HOM damping as far as possible in a single cell. This paper will describe the cavity design with respect to electrical and mechanical features, the fabrication efforts and the results obtained with the different cavities existing at the time of this workshop

  6. Mechanical Design of the HER Synchrotron Light Monitor Primary Mirror

    Energy Technology Data Exchange (ETDEWEB)

    Daly, Edward F.; /SLAC; Fisher, Alan S.; Kurita, Nadine R.; Langton, J.; /SLAC

    2011-09-14

    This paper describes the mechanical design of the primary mirror that images the visible portion of the synchrotron radiation (SR) extracted from the High Energy Ring (HER) of the PEP-II B-Factory. During off-axis operation, the water-cooled GlidCop mirror is subjected to a heat flux in excess of 2000 W/cm2. When on-axis imaging occurs, the heat flux due to scattered SR, resistive wall losses and Higher-Order-Mode (HOM) heating is estimated at 1 W/cm2. The imaging surface is plated with Electroless Nickel to improve its optical characteristics. The design requirements for the primary mirror are listed and discussed. Calculated mechanical distortions and stresses experienced by the mirror during on-axis and off-axis operation will be presented.

  7. A Preliminary Interaction Region Design for a Super B-Factory

    CERN Document Server

    Sullivan, Michael K; Donald, Martin; Ecklund, Stanley; Novokhatski, Alexander; Seeman, John; Wienands, Ulrich

    2005-01-01

    The success of the two B-Factories (PEP-II and KEKB) has encouraged us to look at design parameters for a B-Factory with a 30-50 times increase in the luminosity of the present machines (L~1e36). In order to achieve this high luminosity, the beta y* values are reduced to 3-2 mm, the bunch spacing is minimized (0.6-0.3 m) and the bunch currents are increased. Total beam currents range from 5-25 A. The interaction region (IR) of these "SuperB" designs presents special challenges. Synchrotron radiation fans from local bending in shared magnets and from upstream sources pose difficulties due to the high power levels in these fans. High-order-mode(HOM)heating, effects that have been seen in the present B-factories, will become much more pronounced with the very short bunches and high beam currents. Masking the detector beam pipe from synchrotron radiation must take into account effects of HOM power generation. Backgrounds that are a function of the luminosity will become very important. We presen...

  8. Design of a high repetition rate S-band photocathode gun

    International Nuclear Information System (INIS)

    Han Janghui; Cox, Matthew; Huang, Houcheng; Pande, Shivaji

    2011-01-01

    Photocathode RF guns have been developed in many laboratories for generating high quality electron beams for free-electron lasers based on linear accelerators. Such guns can generate electron beams with an exceptionally high peak current as well as a small transverse emittance. Their applications have been recently expanded for ultrafast electron diffraction, coherent terahertz radiation, and X-ray or γ-ray radiation by Compton scattering. In this paper, we design an S-band normal-conducting gun with capabilities of high quality beam generation and high repetition rate operation. The RF design and thermal analysis of the gun cavity and coupler are introduced. Optimal position of the gun focusing solenoid for low emittance beam generation is found by performing particle tracking simulations. Then, the gun system is designed to be able to afford the optimal solenoid position. The cooling-water channel surrounding the gun cavity and coupler is designed and analyzed numerically. The pressure in the gun is simulated with a vacuum model containing the detailed inner structure of the gun. An injector for a free-electron laser application is designed by using this gun and the beam dynamics simulation is shown. A cold test with a prototype gun for confirmation of the RF design is reported. - Highlights: → We design an S-band gun for low emittance beam generation and high repetition rate operation. → The RF design and thermal analysis of the gun cavity and coupler are studied. → An FEL injector is designed by using this gun and the beam dynamics simulation is shown. → A cold test with a prototype gun for confirmation of the RF design is reported.

  9. Time-Resolved Transient Optical Absorption Study of Bis(terpyridyl)oligothiophenes and Their Metallo-Supramolecular Polymers with Zn(II) Ion Couplers.

    Science.gov (United States)

    Rais, David; Menšík, Miroslav; Štenclová-Bláhová, Pavla; Svoboda, Jan; Vohlídal, Jiří; Pfleger, Jiří

    2015-06-18

    α,ω-Bis(terpyridyl)oligothiophenes spontaneously assemble with Zn(II) ions giving conjugated constitutional dynamic polymers (dynamers) of the metallo-supramolecular class, which potentially might be utilized in optoelectronics. Their photophysical properties, which are of great importance in this field of application, are strongly influenced by the dynamic morphology. It was assessed in this study by using ultrafast pump-probe optical absorption spectroscopy. We identified and characterized relaxation processes running in photoexcited molecules of these oligomers and dynamers and show impacts of disturbed coplanarity of adjacent rings (twisting the thiophene-thiophene and thiophene-terpyridyl bonds by attached hexyl side groups) and Zn(II) ion couplers on these processes. Major effects are seen in the time constants of rotational relaxation, intersystem crossing, and de-excitation lifetimes. The photoexcited states formed on different repeating units within the same dynamer chain do not interact with each other even at very high excitation density. The method is presented that allows determining the equilibrium fraction of unbound oligothiophene species in a dynamer solution, from which otherwise hardly accessible values of the average degree of polymerization of constitutionally dynamic chains in solution can be estimated.

  10. [The application of microvascular anastomotic coupler in vascular anastomosis of free tissue flap for reconstruction of defect after head and neck cancer resection].

    Science.gov (United States)

    Zhang, Y J; Wang, Z H; Li, C H; Chen, J

    2017-09-07

    Objective: To investigate the application and operation skills in vein anastomosis by microvascular anastomotic coupler (MAC) in reconstruction of defects after head and neck cancer resection. Methods: From August 2015 to July 2016, in Department of Head and Neck Surgery, Sichuan Cancer Hosipital, 17 cases underwent the reconstruction of defects after head and neck cancer resection with free tissue flaps, including forearm flaps in 11 casess, anterolateral flaps in 4 casess and fibula flaps in 2 casess. Totally 17 MAC were used, including 14 MAC for end-to-end anastomosis and 3 MAC for end-to-side anastomosis. SPSS 22.0 software was used to analyze the data. Results: Venous anastomoses in 17 free tissue flaps were successfully completed, with no anastomotic errhysis. All flaps survived well. The time required for vascular anastomoses with MAC varied 2-9 min, with average time of (4.2±2.3) min, which was significantly shorter than that with manually anastomosis (17.4 ± 2.7) min ( t =15.1, P anastomosis in free tissue flap for reconstruction of defect after head and neck cancer resection, which requires for less operation time and shows good results.

  11. Optical loss analysis and parameter optimization for fan-shaped single-polarization grating coupler at wavelength of 1.3 µm band

    Science.gov (United States)

    Ushida, Jun; Tokushima, Masatoshi; Sobu, Yohei; Shimura, Daisuke; Yashiki, Kenichiro; Takahashi, Shigeki; Kurata, Kazuhiko

    2018-05-01

    Fan-shaped grating couplers (F-GCs) can be smaller than straight ones but are less efficient in general in coupling to single-mode fibers. To find a small F-GC with sufficiently high fiber-coupling characteristics, we numerically compared the dependencies of coupling efficiencies on wavelengths, the starting width of gratings, and misalignment distances among 25, 45, and 60° tapered angles of fan shape by using the three-dimensional finite-difference time domain method. A F-GC with a tapered angle of 25° exhibited the highest performances for all dependencies. The optical loss origins of F-GCs were discussed in terms of the electric field structures in them and scattering at the joint between the fan-shaped slab and channel waveguide. We fabricated an optimized 25° F-GC by using ArF photolithography, which almost exactly reproduced the optical coupling efficiency and radiation angle characteristics that were numerically expected.

  12. Ferrite HOM Absorber for the RHIC ERL

    Energy Technology Data Exchange (ETDEWEB)

    Hahn,H.; Choi, E.M.; Hammons, L.

    2008-10-01

    A superconducting Energy Recovery Linac is under construction at Brookhaven National Laboratory to serve as test bed for RHIC upgrades. The damping of higher-order modes in the superconducting five-cell cavity for the Energy-Recovery linac at RHIC is performed exclusively by two ferrite absorbers. The ferrite properties have been measured in ferrite-loaded pill box cavities resulting in the permeability values given by a first-order Debye model for the tiled absorber structure and an equivalent permeability value for computer simulations with solid ring dampers. Measured and simulated results for the higher-order modes in the prototype copper cavity are discussed. First room-temperature measurements of the finished niobium cavity are presented which confirm the effective damping of higher-order modes in the ERL. by the ferrite absorbers.

  13. Design and Analysis of an all-fiber MZI Interleaver Based on Fiber Ring Resonator

    Directory of Open Access Journals (Sweden)

    Pu Huilan

    2015-01-01

    Full Text Available An all-fiber Mach-Zehnder interferometer (MZI interleaver using one planar 3×3 fiber coupler, one 2×2 fiber coupler and one 8-shaped fiber ring resonator is developed by the new configuration. Based on its structure, the output spectrum expression is established and described by using the principle of fiber transmission and the matrix transfer function. The results of numerical simulation indicate that when the length difference of interference arms and the coupling coefficients of the couplers are some certain values, it obtains a uniform flat-top passband and similar to rectangular output spectrum. Compared with the traditional MZI interleaver, the isolation in stopband and the rolloff in transition band are strengthen, the 25dB stopband bandwidth and 0.5dB passband bandwidth are simultaneously remarkably improved. Compared with the asymmetrical ring resonator MZI interleaver, the influence of transmission loss on extinction ratio can be effectively reduced. The device has a certain ability to resist the deviation, which reduces the difficulties in fabricating it. The experiment results agree with the theoretical analysis well. The interleaver designed by the proposed approach has favorable performance, which has the potential application value in optical fiber communication system.

  14. Adequação de engates rápidos de aspersores como conectores de mangueira para distribuição de água em sulcos de irrigação Adequacy of quick coupler sprinkler as hose connector for water distribution in furrow irrigation

    Directory of Open Access Journals (Sweden)

    Flaviane F. de Faria

    2008-06-01

    Full Text Available Como forma de reduzir as perdas de água que ocorrem na irrigação empregada na cultura do tomateiro, agricultores vêm utilizando mangueiras de forma precária na distribuição de água aos sulcos. O presente trabalho teve como objetivo estudar a adequação de engates rápidos de aspersores para serem aplicados como conectores de mangueiras por produtores irrigantes que façam uso desse sistema de distribuição de água. A primeira etapa do estudo foi avaliar, em campo, a operacionalidade do uso de mangueiras por produtores que fazem uso desse sistema. Posteriormente, quatro modelos de engates rápidos, disponíveis no mercado, foram ensaiados em laboratório, determinando-se o coeficiente de resistência, o comprimento equivalente, a curva de perda de carga e a eficiência de estanqueidade. Como resultado, apresenta-se o projeto estrutural de um sistema de conexão de mangueiras, utilizando-se do modelo de engate com melhor desempenho e recomendações quanto ao seu uso na distribuição de água. Apesar da necessidade de ensaios adicionais em campo, o sistema proposto tem potencial para otimizar a eficiência do uso da água, melhorar as condições ergonômicas do trabalhador e garantir boa rentabilidade ao produtor.As a way to reduce water losses in furrow irrigation systems, used in fresh market tomato production, farmers are improperly distributing water into the field using plastic hose. The objective of this work was to study the suitability of using quick coupler sprinkler as hose connectors for water distribution in tomato plantation. The first step of the study was to assess the current hose field operation for tomato growers. Subsequently, four models of quick couplers sprinklers available in the market were tested in laboratory to determine the coefficient of resistance, the equivalent tube length, the head loss curve and the linking efficiency. As result, a structural design for hose connectors was presented using the model of

  15. A Cascaded Self-Similar Rat-Race Hybrid Coupler Architecture and its Compact Ka-Band Implementation

    Science.gov (United States)

    2017-03-01

    real-estate and limit the system-level performance, including bandwidth, gain, and energy - efficiency. These many challenges are positioning passive...and are used in numerous RF/mm-wave systems for radar and wireless communications. Although a Marchand balun covers a large bandwidth, it is...requires multiple λ/4 transmission lines (t-lines), making its on-chip designs very costly even for RF/mm-wave bands. Reported miniaturized rat-race

  16. Avaliação endócrina e morfológica de transplante ovariano homógeno Endocrine and morphological assessment of ovarian homologous transplantation

    Directory of Open Access Journals (Sweden)

    Andy Petroianu

    2004-06-01

    Full Text Available INTRODUÇÃO: A insuficiência ovariana decorre de ooforectomia bilateral em diversas afecções do ovário, como neoplasia e sepse, além de quimioterapia, radiação pélvica e fatores relacionados à idade. Suas complicações sistêmicas, como insuficiências hormonais, podem ser de difícil controle. OBJETIVOS: Avaliar aspectos endócrinos e histológicos ovarianos após seu transplante ortotópico, sem anastomose vascular e submetidos à imunossupressão pela ciclosporina. MATERIAL E MÉTODO: Foram utilizadas 12 coelhas da raça Nova Zelândia Branca (n = 6 e Califórnia (n = 6, divididas em dois grupos: grupo 1 (n = 4, de controle, submetido apenas a laparotomia, sem outro procedimento cirúrgico; e grupo 2 (n = 8, submetido a ooforectomia bilateral e transplante ortotópico dos ovários, que foram trocados entre as duas raças de animais. De um lado, foi transplantado o ovário íntegro e, do outro, o ovário fatiado. Não houve anastomose vascular. As coelhas foram imunossuprimidas com ciclosporina (10mg/kg ao dia. No final do período de acompanhamento de seis meses, foram feitas dosagens de estradiol, progesterona, hormônio foliculoestimulante (FSH e hormônio luteinizante (LH, além de estudo histológico de ovários, tuba uterina e útero. RESULTADOS: Os ovários transplantados estavam rodeados por tecido conjuntivo, bem vascularizados, mostrando folículos em diferentes estádios de desenvolvimento. A histologia tubária e uterina também foi preservada em ambos os grupos. A dosagem hormonal foi normal em todas as coelhas, indicando que, do ponto de vista endócrino, o ovário transplantado estava funcionando. O transplante ovariano homógeno ortotópico, sem pedículo vascular e submetido à imunossupressão pela ciclosporina, foi eficaz para a manutenção de hormônios ovarianos em níveis normais.INTRODUCTION: Ovarian failure may be due to bilateral oophorectomy on several ovarian diseases, such as infection and neoplasm

  17. Retalho ósseo pré-fabricado com osso homógeno: estudo da maturação óssea em um modelo experimental Prefabricated homogenous bone flap: bone maturation study as an experimental model

    Directory of Open Access Journals (Sweden)

    Alfredo Benjamim Duarte da Silva

    2000-01-01

    Full Text Available As opções convencionais de tratamento de perdas ósseas, como enxertos e retalhos não são satisfatórias. Com isso uma nova categoria de retalhos, o retalho pré-fabricado (RPF, passou a ser estudada. Foram retirados 42 ossos metatársicos-I das patas traseiras de 21 ratos Wistar. O grupo I (n=21 foi descalcificado e liofilizado e o grupo II (n=21 foi não descalcificado e congelado a -70°C. Após 3 semanas os ossos foram enxertados em 21 animais sobre os vasos epigástricos inferiores nas regiões inguinal direita e esquerda, individualizados por uma lâmina de silicone. Os grupos I e II foram divididos em três subgrupos cada, de acordo com o tempo de permanência (1, 2 e 4 semanas após a pré-fabricação do retalho. No estudo histológico macroscópico os grupos apresentaram diferenças em morfologia e consistência: o grupo I mostrou perda da arquitetura óssea e da rigidez e grupo II mantiveram sua forma, rigidez e consistência. Na análise qualitativa alterações foram observadas nos fragmentos do grupo desmineralizado e liofilizado, especialmente no subgrupo de 2 semanas. O grupo II não apresentou alteração no aspecto do tecido ósseo mineralizado entre os diversos subgrupos. É nítida a diferença histológica entre os RPF com osso descalcificado e liofilizado quando comparado ao não descalcificado e congelado. A reabsorção óssea gradual sugere que a rotação do retalho deve ocorrer precocemente. Este estudo demonstra a aplicabilidade do osso homógeno para pré-fabricação de retalhos.As conventional options for bone repair are not satisfactory, a new flap category was developed, the prefabricated flap (RPF. 42 metatarsic-I bone were obtained from 21 Wistar rats, and divided in two groups: group I (n=21 the bones were freeze- dryed and decalcified and group II (n=21 was frozen to - 70º C. After 3 weeks the bones were grafted in 21 rats, onto the left na right inferior epigastric vessels wrapped in silicon sheet

  18. Modèle tridimensionnel pour coupler les équations magnétiques et électriques dans le cas de la magnétostatique

    Science.gov (United States)

    Piriou, F.; Razek, A.

    1991-03-01

    In this paper a 3D model for coupling of magnetic and electric equations is presented. The magnetic equations are solved with the help of finite element method using the magnetic vector potential formulation. To take into account the effects of magnetic saturation we use the Newton-Raphson algorithm. We develop the analysis permitting the coupling of magnetic and electric equations to obtain a difrerential system equations which can be solved with numerical integration. As example we model an iron core coil and the validity of our model is verified by a comparison of the obtained results with an analytical solution and a 2D code calculation. Dans cet article est présenté un modèle 3D qui permet de coupler les équations magnétiques et électriques. Les équations magnétiques sont résolues à l'aide de la méthode des éléments finis en utilisant une formulation en potentiel vecteur magnétique. Dans le modèle proposé les effets de la saturation du circuit magnétique sont pris en compte en utilisant l'algorithme de Newton-Raphson. On montre comment relier les équations magnétiques avec celles du circuit électrique pour aboutir à un système d'équations différentielles que l'on résout avec une intégration numérique. A titre d'exemple on modélise une bobine à noyau ferromagnétique et pour montrer la validité du modèle on compare les résultats obtenus avec une solution analytique et un code de calcul 2D.

  19. Gallium Nitride (GaN) Monolithic Microwave Integrated Circuit (MMIC) Designs Submitted to Air Force Research Laboratory (AFRL) Sponsored Qorvo Fabrication

    Science.gov (United States)

    2017-07-01

    of interest to Department of Defense applications, particularly for next-generation radar systems. Broadband, efficient, high-power MMIC amplifiers...handling capability. Figures 1 and 2 show the layouts and simulations of a simple 1-stage 3- to 6-GHz Wilkinson coupler/combiner. A 2-stage broader band...from 4 to nearly 7 GHz for the 2-stage PA design. The simple , compact broadband feedback amplifier that serves as the first-stage driver for the 2

  20. Design and Development of RF Structures for Linac4

    CERN Document Server

    Vretenar, M; Gerigk, F; Pasini, M; Wegner, R

    2006-01-01

    Linac4 is a new 160 MeV H− linac proposed at CERN to replace the 50 MeV Linac2 as injector to the PS Booster, with the goal of doubling its brightness and intensity. The present design foresees after RFQ and chopping line a sequence of three accelerating structures: a Drift Tube Linac (DTL) from 3 to 40 MeV, a Cell-Coupled DTL (CCDTL) to 90 MeV and a Side Coupled Linac (SCL) up to the final energy. The DTL and CCDTL operate at 352 MHz, while in the SCL the frequency is doubled to 704 MHz. Although the injection in the PS Booster requires only a low duty cycle, the accelerating structures are designed to operate at the high duty cycle required by a possible future extension to a high-power linac driver for a neutrino facility. This paper presents the different accelerating structures, underlining the progress in the design of critical resonator elements, like post-couplers in the DTL, coupling slots in the CCDTL and bridge couplers for the SCL. Prototyping progress for the different structures is reported...

  1. Designs for a quantum electron microscope

    International Nuclear Information System (INIS)

    Kruit, P.; Hobbs, R.G.; Kim, C-S.; Yang, Y.; Manfrinato, V.R.; Hammer, J.; Thomas, S.; Weber, P.; Klopfer, B.; Kohstall, C.; Juffmann, T.; Kasevich, M.A.; Hommelhoff, P.; Berggren, K.K.

    2016-01-01

    One of the astounding consequences of quantum mechanics is that it allows the detection of a target using an incident probe, with only a low probability of interaction of the probe and the target. This ‘quantum weirdness’ could be applied in the field of electron microscopy to generate images of beam-sensitive specimens with substantially reduced damage to the specimen. A reduction of beam-induced damage to specimens is especially of great importance if it can enable imaging of biological specimens with atomic resolution. Following a recent suggestion that interaction-free measurements are possible with electrons, we now analyze the difficulties of actually building an atomic resolution interaction-free electron microscope, or “quantum electron microscope”. A quantum electron microscope would require a number of unique components not found in conventional transmission electron microscopes. These components include a coherent electron beam-splitter or two-state-coupler, and a resonator structure to allow each electron to interrogate the specimen multiple times, thus supporting high success probabilities for interaction-free detection of the specimen. Different system designs are presented here, which are based on four different choices of two-state-couplers: a thin crystal, a grating mirror, a standing light wave and an electro-dynamical pseudopotential. Challenges for the detailed electron optical design are identified as future directions for development. While it is concluded that it should be possible to build an atomic resolution quantum electron microscope, we have also identified a number of hurdles to the development of such a microscope and further theoretical investigations that will be required to enable a complete interpretation of the images produced by such a microscope. - Highlights: • Quantum electron microscopy has the potential of reducing radiation damage. • QEM requires a fraction of the electron wave to pass through the sample

  2. Designs for a quantum electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Kruit, P., E-mail: p.kruit@tudelft.nl [Department of Imaging Physics, Delft University of Technology, Lorentzweg 1, 2628CJ Delft (Netherlands); Hobbs, R.G.; Kim, C-S.; Yang, Y.; Manfrinato, V.R. [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hammer, J.; Thomas, S.; Weber, P. [Department of Physics, Friedrich Alexander University Erlangen-Nürnberg (FAU), Staudtstrasse 1, d-91058 Erlangen (Germany); Klopfer, B.; Kohstall, C.; Juffmann, T.; Kasevich, M.A. [Department of Physics, Stanford University, Stanford, California 94305 (United States); Hommelhoff, P. [Department of Physics, Friedrich Alexander University Erlangen-Nürnberg (FAU), Staudtstrasse 1, d-91058 Erlangen (Germany); Berggren, K.K. [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2016-05-15

    One of the astounding consequences of quantum mechanics is that it allows the detection of a target using an incident probe, with only a low probability of interaction of the probe and the target. This ‘quantum weirdness’ could be applied in the field of electron microscopy to generate images of beam-sensitive specimens with substantially reduced damage to the specimen. A reduction of beam-induced damage to specimens is especially of great importance if it can enable imaging of biological specimens with atomic resolution. Following a recent suggestion that interaction-free measurements are possible with electrons, we now analyze the difficulties of actually building an atomic resolution interaction-free electron microscope, or “quantum electron microscope”. A quantum electron microscope would require a number of unique components not found in conventional transmission electron microscopes. These components include a coherent electron beam-splitter or two-state-coupler, and a resonator structure to allow each electron to interrogate the specimen multiple times, thus supporting high success probabilities for interaction-free detection of the specimen. Different system designs are presented here, which are based on four different choices of two-state-couplers: a thin crystal, a grating mirror, a standing light wave and an electro-dynamical pseudopotential. Challenges for the detailed electron optical design are identified as future directions for development. While it is concluded that it should be possible to build an atomic resolution quantum electron microscope, we have also identified a number of hurdles to the development of such a microscope and further theoretical investigations that will be required to enable a complete interpretation of the images produced by such a microscope. - Highlights: • Quantum electron microscopy has the potential of reducing radiation damage. • QEM requires a fraction of the electron wave to pass through the sample

  3. Design considerations for a backlight with switchable viewing angles

    Science.gov (United States)

    Fujieda, Ichiro; Takagi, Yoshihiko; Rahadian, Fanny

    2006-08-01

    Small-sized liquid crystal displays are widely used for mobile applications such as cell phones. Electronic control of a viewing angle range is desired in order to maintain privacy for viewing in public as well as to provide wide viewing angles for solitary viewing. Conventionally, a polymer-dispersed liquid crystal (PDLC) panel is inserted between a backlight and a liquid crystal panel. The PDLC layer either transmits or scatters the light from the backlight, thus providing an electronic control of viewing angles. However, such a display system is obviously thick and expensive. Here, we propose to place an electronically-controlled, light-deflecting device between an LED and a light-guide of a backlight. For example, a liquid crystal lens is investigated for other applications and its focal length is controlled electronically. A liquid crystal phase grating either transmits or diffracts an incoming light depending on whether or not a periodic phase distribution is formed inside its liquid crystal layer. A bias applied to such a device will control the angular distribution of the light propagating inside a light-guide. Output couplers built in the light-guide extract the propagating light to outside. They can be V-shaped grooves, pyramids, or any other structures that can refract, reflect or diffract light. When any of such interactions occur, the output couplers translate the changes in the propagation angles into the angular distribution of the output light. Hence the viewing-angle characteristic can be switched. The designs of the output couplers and the LC devices are important for such a backlight system.

  4. Broadband silicon polarization beam splitter with a high extinction ratio using a triple-bent-waveguide directional coupler.

    Science.gov (United States)

    Ong, Jun Rong; Ang, Thomas Y L; Sahin, Ezgi; Pawlina, Bryan; Chen, G F R; Tan, D T H; Lim, Soon Thor; Png, Ching Eng

    2017-11-01

    We report on the design and experimental demonstration of a broadband silicon polarization beam splitter (PBS) with a high extinction ratio (ER)≥30  dB. This was achieved using triple-bent-waveguide directional coupling in a single PBS, and cascaded PBS topology. For the single PBS, the bandwidths for an ER≥30  dB are 20 nm for the quasi-TE mode, and 70 nm for the quasi-TM mode when a broadband light source (1520-1610 nm) was employed. The insertion loss (IL) varies from 0.2 to 1 dB for the quasi-TE mode and 0.2-2 dB for the quasi-TM mode. The cascaded PBS improved the bandwidth of the quasi-TE mode for an ER≥30  dB to 90 nm, with a low IL of 0.2-2 dB. To the best of our knowledge, our PBS system is one of the best broadband PBSs with an ER as high as ∼42  dB and a low IL below 1 dB around the central wavelength, and experimentally demonstrated using edge-coupling.

  5. RF Design of the TW Buncher for the CLIC Drive Beam Injector (2nd report)

    CERN Document Server

    Shaker, Hamed

    2016-01-01

    CLIC is based on the two beams concept that one beam (drive beam) produces the required RF power to accelerate another beam (main beam). The drive beam is produced and accelerated up to 50MeV inside the CLIC drive beam injector. The drive beam injector main components are a thermionic electron gun, three sub-harmonic bunchers, a pre-buncher, a TW buncher, 13 accelerating structures and one magnetic chicane. This document is the second report of the RF structure design of the TW buncher. This design is based on the beam dynamic design done by Shahin Sanaye Hajari due to requirements mentioned in CLIC CDR. A disk-loaded tapered structure is chosen for the TW buncher. The axial electric field increases strongly based on the beam dynamic requirements. This second report includes the study of HOM effects, retuning the cells, study of dimensional tolerances and the heat dissipation on the surface.

  6. Implante de condrócitos homólogos em defeitos osteocondrais de cães: padronização da técnica e avaliação histopatológica Homologous articular chondrocytes implantation in osteochondral defects of dogs: technique and histopathological evaluation standardization

    Directory of Open Access Journals (Sweden)

    L.S. Iamaguti

    2013-02-01

    Full Text Available Padronizou-se a metodologia para cultura de condrócitos em cães e avaliou-se seu implante em lesões osteocondrais, utilizando-se a membrana biossintética de celulose (MBC como revestimento. Dez cães, adultos e clinicamente sadios, foram submetidos à artrotomia das articulações fêmoro-tíbio-patelares. Defeitos de 4mm de diâmetro e profundidade foram induzidos no sulco troclear de ambos os membros. MBC foi aplicada na base e na superfície das lesões. Os defeitos do membro direito foram preenchidos com condrócitos homólogos cultivados formando o grupo-tratado (GT; os do membro esquerdo, sem implante celular, foram designados grupo-controle (GC. A evolução pós-operatória foi analisada com especial interesse nos processos de reparação da lesão, por meio de histomorfometria e imuno-histoquímica para colágeno tipo II e sulfato de condroitina. A cultura de condrócitos homólogos apresentou alta densidade e taxa de viabilidade. Observou-se integridade do tecido neoformado com a cartilagem adjacente na avaliação histológica, em ambos os grupos. Na imuno-histoquímica, verificou-se predomínio de colágeno tipo II no GT. Morfometricamente, não houve diferença significativa entre o tecido fibroso e o fibrocartilaginoso entre os grupos. A cultura de condrócitos homólogos de cães foi exequível. O tecido neoformado apresentou qualidade discretamente superior associado ao implante homólogo de condrócitos, contudo não promoveu reparação por cartilagem hialina.The aim of the study is to standardize the methodology to achieve canine chondrocytes culture, and evaluate its implant on osteochondral defects made in the femoral trochlear sulcus of dogs, using the cellulose biosynthetic membrane (CBM as coating. Ten healthy adult dogs without locomotor disorders were used. All animals were submitted to arthrotomy of stifle joints and defects of four millimeters in diameter x four millimeters deep were done in the femoral trochlear

  7. Design and application of multilayer monolithic microwave integrated circuit transformers

    Energy Technology Data Exchange (ETDEWEB)

    Economides, S.B

    1999-07-01

    The design and performance of planar spiral transformers, using multilayer GaAs and silicon MMIC technology, are presented. This multilayer technology gives new opportunities for improving the performance of planar transformers, couplers and baluns. Planar transformers have high parasitic resistance and capacitance and low levels of coupling. Using multilayer technology these problems are overcome by applying a multilayer structure of three metal layers separated by two polyimide dielectric layers. The improvements gained by placing the conductors on different metal layers, and using conductors raised on polyimide layers for low capacitance, have been investigated. The circuits were fabricated using a novel experimental fabrication process, which uses entirely standard materials and techniques and is compatible with BJT's and silicon-germanium HBT's. The transformers were all characterised up to 20 GHz using RF-on-wafer measurements. They demonstrated good performance, considering the experimental nature of in-house multilayer technology and the difficulties in simulating these three-dimensional new geometries. With high resistivity substrates, the silicon components achieved virtually the same performance as their gallium arsenide counterparts. The transformers were then used in simulations of transformer-coupled HBT amplifier circuits, to demonstrate their capabilities. It was shown that these circuits present good performance compared to standard off-the shelf component circuits and are very promising for use in most multilayer MMIC applications. The structures were further used in coupling configurations, and applied in balun circuits and pushpull amplifiers. The spiral transformer coupler can operate at low frequencies without using up much chip area. In a balun configuration, the balun can compensate for coupling and phase imbalance and operates over 5 to 15 GHz. The spiral coupler does not always need multilayer processing, so the balun may be

  8. Design, Fabrication and Measurement of the First Rounded Damped Detuned Accelerator Structure (RDDS1)

    International Nuclear Information System (INIS)

    Wang, Juwen

    2000-01-01

    As a joint effort in the JLC/NLC research program, the authors have developed a new type of damped detuned accelerator structure with optimized round-shaped cavities (RDDS). This paper discusses some important R and D aspects of the first structure in this series (RDDS1). The design aspects covered are the cell design with sub-MHz precision, HOM detuning, coupling and damping technique and wakefield simulation. The fabrication issues covered are ultra-precision cell machining with micron accuracy, assembly and diffusion bonding technologies to satisfactorily meet bookshelf, straightness and cell rotational alignment requirements. The measurements described are the RF properties of single cavities and complete accelerator section, as well as wakefields from the ASSET tests at SLAC. Finally, future improvements are also discussed

  9. Designs for a quantum electron microscope.

    Science.gov (United States)

    Kruit, P; Hobbs, R G; Kim, C-S; Yang, Y; Manfrinato, V R; Hammer, J; Thomas, S; Weber, P; Klopfer, B; Kohstall, C; Juffmann, T; Kasevich, M A; Hommelhoff, P; Berggren, K K

    2016-05-01

    One of the astounding consequences of quantum mechanics is that it allows the detection of a target using an incident probe, with only a low probability of interaction of the probe and the target. This 'quantum weirdness' could be applied in the field of electron microscopy to generate images of beam-sensitive specimens with substantially reduced damage to the specimen. A reduction of beam-induced damage to specimens is especially of great importance if it can enable imaging of biological specimens with atomic resolution. Following a recent suggestion that interaction-free measurements are possible with electrons, we now analyze the difficulties of actually building an atomic resolution interaction-free electron microscope, or "quantum electron microscope". A quantum electron microscope would require a number of unique components not found in conventional transmission electron microscopes. These components include a coherent electron beam-splitter or two-state-coupler, and a resonator structure to allow each electron to interrogate the specimen multiple times, thus supporting high success probabilities for interaction-free detection of the specimen. Different system designs are presented here, which are based on four different choices of two-state-couplers: a thin crystal, a grating mirror, a standing light wave and an electro-dynamical pseudopotential. Challenges for the detailed electron optical design are identified as future directions for development. While it is concluded that it should be possible to build an atomic resolution quantum electron microscope, we have also identified a number of hurdles to the development of such a microscope and further theoretical investigations that will be required to enable a complete interpretation of the images produced by such a microscope. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  10. Design of an X-band accelerating structure using a newly developed structural optimization procedure

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaoxia [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Fang, Wencheng; Gu, Qiang [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhao, Zhentang, E-mail: zhaozhentang@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2017-05-11

    An X-band high gradient accelerating structure is a challenging technology for implementation in advanced electron linear accelerator facilities. The present work discusses the design of an X-band accelerating structure for dedicated application to a compact hard X-ray free electron laser facility at the Shanghai Institute of Applied Physics, and numerous design optimizations are conducted with consideration for radio frequency (RF) breakdown, RF efficiency, short-range wakefields, and dipole/quadrupole field modes, to ensure good beam quality and a high accelerating gradient. The designed X-band accelerating structure is a constant gradient structure with a 4π/5 operating mode and input and output dual-feed couplers in a racetrack shape. The design process employs a newly developed effective optimization procedure for optimization of the X-band accelerating structure. In addition, the specific design of couplers providing high beam quality by eliminating dipole field components and reducing quadrupole field components is discussed in detail.

  11. Design and construction of the main linac module for the superconducting energy recovery linac project at Cornell

    Energy Technology Data Exchange (ETDEWEB)

    Eichhorn, R.; Bullock, B.; He, Y.; Hoffstaetter, G.; Liepe, M.; O' Connell, T.; Quigley, P.; Sabol, D.; Sears, J.; Smith, E.; Veshcherevich, V. [Cornell Laboratory for Accelerator-based Science and Education (CLASSE), Cornell University, 161 Synchrotron Drive, Ithaca, NY 14853 (United States)

    2014-01-29

    Cornell University has been designing and building superconducting accelerators for various applications for more than 50 years. Currently, an energy-recovery linac (ERL) based synchrotron-light facility is proposed making use of the existing CESR facility. As part of the phase 1 R and D program funded by the NSF, critical challenges in the design were addressed, one of them being a full linac cryo-module. It houses 6 superconducting cavities- operated at 1.8 K in continuous wave (CW) mode - with individual HOM absorbers and one magnet/ BPM section. Pushing the limits, a high quality factor of the cavities (2⋅10{sup 10}) and high beam currents (100 mA accelerated plus 100 mA decelerated) are targeted. We will present the design of the main linac cryo-module (MLC) being finalized recently, its cryogenic features and report on the status of the fabrication which started in late 2012.

  12. Numerical design of an rf-coupling Iris

    International Nuclear Information System (INIS)

    Hanaki, H.

    1991-07-01

    For an rf coupler of an rf system in high-quality transmission an analytical method may be applied to treat the design problem, if a coupling hole between cavities or waveguides is small enough. However, in most cases of accelerator engineering the dimensions of the coupling slots are not so small compared with the size of a cavity and a waveguide. Numerical design of rf coupling slots for a few cases is tried basically according to Henke's method using an equivalent circuit to treat the matching of microwave components, but taking account of beam loading expressed by the coupling coefficient β. The MAFIA code has been applied for the design. (R.P.) 5 refs., 10 figs., 3 tabs

  13. Design and rf tuning of the KEK 40 MeV proton linear accelerator

    International Nuclear Information System (INIS)

    Kato, Takao.

    1986-09-01

    An Alvarez linac was designed and constructed on the basis of a model linac study to increase the output energy from 20 to 40 MeV. The linac was tuned by frequency tuners and post couplers. Stabilization of the field was achieved and a variation within ± 0.7 % of the accelerating field was obtained. An equivalent circuit analysis which can numerically solve loop equations, including stem and post currents in addition to tank current, can explain the rf characteristics of a postcoupled structure. (author)

  14. Reparação do diafragma de cães com segmento muscular homólogo ortotópico conservado em solução supersaturada de açúcar Diaphragm repair in dogs with muscular homologous ortothopic segment preserved in supersaturated sugar solution

    Directory of Open Access Journals (Sweden)

    A. Mazzanti

    2001-02-01

    Full Text Available O uso de enxerto muscular homólogo conservado em solução supersaturada de açúcar a 300% foi pesquisado no músculo diafragma de cães. Foram utilizados 12 cães adultos, quatro machos e oito fêmeas, sem raça definida, com peso entre 9 e 18kg, para confecção de um defeito diafragmático na porção muscular, com dimensões de 4,0 × 4,5cm, seguido da implantação de um segmento de músculo diafragma homólogo. Seis cães foram observados por um período de 30 dias de pós-operatório e seis por 60 dias, quando foram reoperados para observação macroscópica e coleta de amostra para avaliação histológica. Nos animais do grupo de 30 dias de pós-operatório verificou-se substituição parcial e nos de 60 dias, substituição total da porção muscular do diafragma por tecido de granulação, o que permitiu o restabelecimento completo do diafragma por meio de firme inserção. O segmento de músculo diafragma homólogo conservado em solução supersaturada de açúcar a 300%, em temperatura ambiente, pode ser utilizado para reparação de defeitos diafragmáticos, uma vez que é substituído por tecido conjuntivo fibroso, sem apresentar sinais clínicos nem histológico de rejeição.The viability of tissular healing of a muscular homologous ortothopic diaphragmatic segment preserved in hipersaturated sugar solution at 300% was studied as an implant in the canine diaphragmatic muscle. Twelve adult mongrel dogs were used, four males, and eight females weighing 9 to 18kg. A diaphragmatic defect, measuring 4.0 × 4.5 cm, was provoked in the muscular portion of the diaphragm for the implantation of the homologous diaphragmatic muscle segment. Six animals were observed for 30 days after the surgery and the other six for 60 days. After this period, they were reoperated, for macroscopic observation and collection of samples for histologic evaluation. A partial replacement of the implant was observed in the 30-day observation group whereas in

  15. High power tests of the prototype 352 MHz beta 0.85 five cell cavity for the TRASCO project

    International Nuclear Information System (INIS)

    Chiaveri, E.; Losito, R.; Calatroni, S.

    2003-01-01

    The Five-cell beta 0.85 cavities built at CERN for the development of the TRASCO project is fully tested at the CERN SL-CT Test Bench. The cavity, built using the standard Niobium on Copper technique, was previously tested in a vertical cryostat, showing Qo and Field exceeding the design goal for the TRASCO Project (2.5x10 9 and 5.5 MV/m at 4.5 K). After the successful test we decided to check the performances of the cavity installed in a horizontal Cryostat and equipped with a LEP-II Type high power main coupler and HOM couplers. The cavity was equipped with the Helium Tank, Tuners and couplers at CERN and tested at the SL-CT facility at CERN under a collaboration agreement between INFN and CERN. The behavior of the fully equipped cavity substantially confirmed the results of the preliminary production tests in the vertical Cryostat. The quality factor at low field was substantially unchanged. No MP activity was detected confirming the soundness of the design and the quality of the surface treatment. (author)

  16. Advanced specialty fiber designs for high power fiber lasers

    Science.gov (United States)

    Gu, Guancheng

    The output power of fiber lasers has increased rapidly over the last decade. There are two major limiting factors, namely nonlinear effects and transverse mode instability, prohibiting the power scaling capability of fiber lasers. The nonlinear effects, originating from high optical intensity, primarily limit the peak power scaling. The mode instability, on the other hand, arises from quantum-defect driven heating, causing undesired mode coupling once the power exceeds the threshold and degradation of beam quality. The mode instability has now become the bottleneck for average output power scaling of fiber lasers. Mode area scaling is the most effective way to mitigate nonlinear effects. However, the use of large mode area may increase the tendency to support multiple modes in the core, resulting in lower mode instability threshold. Therefore, it is critical to maintain single mode operation in a large mode area fiber. Sufficient higher order mode suppression can lead to effective single-transverse-mode propagation. In this dissertation, we explore the feasibility of using specialty fiber to construct high power fiber lasers with robust single-mode output. The first type of fiber discussed is the resonantly-enhanced leakage channel fiber. Coherent reflection at the fiber outer boundary can lead to additional confinement especially for highly leaky HOM, leading to lower HOM losses than what are predicted by conventional finite element mothod mode solver considering infinite cladding. In this work, we conducted careful measurements of HOM losses in two leakage channel fibers (LCF) with circular and rounded hexagonal boundary shapes respectively. Impact on HOM losses from coiling, fiber boundary shapes and coating indexes were studied in comparison to simulations. This work demonstrates the limit of the simulation method commonly used in the large-mode-area fiber designs and the need for an improved approach. More importantly, this work also demonstrates that a

  17. A coaxial ring-sidearm power extraction design

    International Nuclear Information System (INIS)

    Ben-Menahem, S.; Yu, D.

    1996-01-01

    We report a successful klystron power extraction design, in which a TEM coaxial mode is transmitted into TE10 mode of a WR90 rectangular waveguide at 11.42 GHz, with very little TEM reflection and almost vanishing asymmetric (TEM → TE11, or monopole to dipole) reflectance. Our coupler consists of a ring (disk) around the coaxial waveguide, and a coax-WR90 sidearm junction. The methods used in the design are numerical simulation, performed on the MAFIA3 T3 time- domain module and on the High Frequency Structure Simulator, and analytical treatment to guide the numerical runs. The demerit parameters (dipole reflectance and TEM reflection) can be reduced as much as desired (to zero in principle), the only limitation being computer run time and memory. Results are accurate to a few percent

  18. Beam position diagnostics with higher order modes in third harmonic superconducting accelerating cavities

    International Nuclear Information System (INIS)

    Zhang, Pei

    2013-02-01

    Higher order modes (HOM) are electromagnetic resonant fields. They can be excited by an electron beam entering an accelerating cavity, and constitute a component of the wakefield. This wakefield has the potential to dilute the beam quality and, in the worst case, result in a beam-break-up instability. It is therefore important to ensure that these fields are well suppressed by extracting energy through special couplers. In addition, the effect of the transverse wakefield can be reduced by aligning the beam on the cavity axis. This is due to their strength depending on the transverse offset of the excitation beam. For suitably small offsets the dominant components of the transverse wakefield are dipole modes, with a linear dependence on the transverse offset of the excitation bunch. This fact enables the transverse beam position inside the cavity to be determined by measuring the dipole modes extracted from the couplers, similar to a cavity beam position monitor (BPM), but requires no additional vacuum instrumentation. At the FLASH facility in DESY, 1.3 GHz (known as TESLA) and 3.9 GHz (third harmonic) cavities are installed. Wakefields in 3.9 GHz cavities are significantly larger than in the 1.3 GHz cavities. It is therefore important to mitigate the adverse effects of HOMs to the beam by aligning the beam on the electric axis of the cavities. This alignment requires an accurate beam position diagnostics inside the 3.9 GHz cavities. It is this aspect that is focused on in this thesis. Although the principle of beam diagnostics with HOM has been demonstrated on 1.3 GHz cavities, the realization in 3.9 GHz cavities is considerably more challenging. This is due to the dense HOM spectrum and the relatively strong coupling of most HOMs amongst the four cavities in the third harmonic cryo-module. A comprehensive series of simulations and HOM spectra measurements have been performed in order to study the modal band structure of the 3.9 GHz cavities. The dependencies of

  19. Beam position diagnostics with higher order modes in third harmonic superconducting accelerating cavities

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pei

    2013-02-15

    Higher order modes (HOM) are electromagnetic resonant fields. They can be excited by an electron beam entering an accelerating cavity, and constitute a component of the wakefield. This wakefield has the potential to dilute the beam quality and, in the worst case, result in a beam-break-up instability. It is therefore important to ensure that these fields are well suppressed by extracting energy through special couplers. In addition, the effect of the transverse wakefield can be reduced by aligning the beam on the cavity axis. This is due to their strength depending on the transverse offset of the excitation beam. For suitably small offsets the dominant components of the transverse wakefield are dipole modes, with a linear dependence on the transverse offset of the excitation bunch. This fact enables the transverse beam position inside the cavity to be determined by measuring the dipole modes extracted from the couplers, similar to a cavity beam position monitor (BPM), but requires no additional vacuum instrumentation. At the FLASH facility in DESY, 1.3 GHz (known as TESLA) and 3.9 GHz (third harmonic) cavities are installed. Wakefields in 3.9 GHz cavities are significantly larger than in the 1.3 GHz cavities. It is therefore important to mitigate the adverse effects of HOMs to the beam by aligning the beam on the electric axis of the cavities. This alignment requires an accurate beam position diagnostics inside the 3.9 GHz cavities. It is this aspect that is focused on in this thesis. Although the principle of beam diagnostics with HOM has been demonstrated on 1.3 GHz cavities, the realization in 3.9 GHz cavities is considerably more challenging. This is due to the dense HOM spectrum and the relatively strong coupling of most HOMs amongst the four cavities in the third harmonic cryo-module. A comprehensive series of simulations and HOM spectra measurements have been performed in order to study the modal band structure of the 3.9 GHz cavities. The dependencies of

  20. Optimizing of the higher order mode dampers in the 56MHz SRF cavity

    International Nuclear Information System (INIS)

    Wu, Q.; Ben-Zvi, I.

    2010-01-01

    Earlier, we reported that a 56 MHz cavity was designed for a luminosity upgrade of the RHIC, and presented the requirements for Higher Order Mode (HOM) damping, the design of the HOM dampers, along with measurements and simulations of the HOM dampers. In this report, we describe our optimization of the dampers performance, and the modifications we made to their original design. We also optimized the number of the HOM dampers, and tested different configurations of locations for them.

  1. A planar waveguide optical discrete Fourier transformer design for 160 Gb/s all-optical OFDM systems

    Science.gov (United States)

    Li, Wei; Liang, Xiaojun; Ma, Weidong; Zhou, Tianhong; Huang, Benxiong; Liu, Deming

    2010-01-01

    A cost-effective all-optical discrete Fourier transformer (ODFT) is designed based on a silicon planar lightwave circuit (PLC), which can be applied to all-optical orthogonal frequency division multiplexing (OFDM) transmission systems and can be achieved by current techniques. It consists of 2 × 2 directional couplers, phase shifters and optical delay lines. Metal-film heaters are used as phase shifters, according to the thermooptic effect of SiO 2. Based on the ODFT, a 160 Gb/s OFDM system is set up. Simulation results show excellent bit error rate (BER) and optical signal-to-noise ratio (OSNR) performances after 400 km transmission.

  2. Modeling and design of an X-band rf photoinjector

    Directory of Open Access Journals (Sweden)

    R. A. Marsh

    2012-10-01

    Full Text Available A design for an X-band rf photoinjector that was developed jointly by SLAC National Accelerator Laboratory (SLAC and Lawrence Livermore National Laboratory (LLNL is presented. The photoinjector is based around a 5.59 cell rf gun that has state-of-the-art features including: elliptical contoured irises; improved mode separation; an optimized initial half cell length; a racetrack input coupler; and coupling that balances pulsed heating with cavity fill time. Radio-frequency and beam dynamics modeling have been done using a combination of codes including PARMELA, HFSS, IMPACT-T, ASTRA, and the ACE3P suite of codes developed at SLAC. The impact of lower gradient operation, magnet misalignment, solenoid multipole errors, beam offset, mode beating, wakefields, and beam line symmetry have been analyzed and are described. Fabrication and testing plans at both LLNL and SLAC are discussed.

  3. A preliminary design of the collinear dielectric wakefield accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Zholents, A.; Gai, W.; Doran, S.; Lindberg, R.; Power, J.G.; Strelnikov, N.; Sun, Y.; Trakhtenberg, E.; Vasserman, I. [ANL, Argonne, IL 60439 (United States); Jing, C.; Kanareykin, A.; Li, Y. [Euclid Techlabs LLC, Solon, OH 44139 (United States); Gao, Q. [Tsinghua University, Beijing (China); Shchegolkov, D.Y.; Simakov, E.I. [LANL, Los Alamos, NM 87545 (United States)

    2016-09-01

    A preliminary design of the multi-meter long collinear dielectric wakefield accelerator that achieves a highly efficient transfer of the drive bunch energy to the wakefields and to the witness bunch is considered. It is made from ~0.5 m long accelerator modules containing a vacuum chamber with dielectric-lined walls, a quadrupole wiggler, an rf coupler, and BPM assembly. The single bunch breakup instability is a major limiting factor for accelerator efficiency, and the BNS damping is applied to obtain the stable multi-meter long propagation of a drive bunch. Numerical simulations using a 6D particle tracking computer code are performed and tolerances to various errors are defined.

  4. Composite driveshaft prototype design and survivability testing

    NARCIS (Netherlands)

    Henry, Todd C.; Riddick, Jaret C.; Mills, Brent T.; Habtour, Ed M.

    2017-01-01

    Rotorcraft drivelines typically utilize a multi-segmented metallic system to transmit power between the engine and tail rotor. The typical arrangement of metal driveshaft segments, hanger bearings, and flexible couplers contribute to a significant logistical footprint, maintenance downtime, and

  5. Department of Accelerator Physics and Technology - Overview

    International Nuclear Information System (INIS)

    Wronka, S.

    2010-01-01

    Full text: The activity of the P-10 department is focused on the development of new acceleration techniques and technology, as well as on applications of particle accelerators. Our team is able to perform all kind of calculations of research, medical and industrial accelerator components, including accelerating cavities, magnets, transfer lines, sources and targets, collimators and applicators. The main topic of the 2010 was the realization of the ' Accelerators and Detectors ' project. All results of this work are included in detailed descriptions of the particular machines. The other tasks are summarized below: 1) WP-06 Task in the European XFEL Project As part of the EXFEL preparatory phase, IPJ is developing HOM and Pickup output lines from superconducting cavities antennas, and Beam Line Absorbers of travelling HOM. This abridged WP-06 task is wholly realized by IPJ and belongs to WPG-1 (Work Package Group 1- Cold linac). The HOM couplers are used to extract and to dissipate Radio Frequency ('' RF '') energy present in the cavity due to the excitation of the HOMs by the electron beam bunches. The low frequency part of the HOM spectrum (below the cut-off frequency of the beam tube) will be extracted by HOM couplers and transmitted via coax lines to external loads. Each 9-cell cavity is equipped with two HOM couplers placed close to the end cells and working in a 2K environment. The propagating HOM power will be ca. 5.4 W/cryomodule for operation with 40000 bunches/s of a nominal charge of 1 nCoulomb. Power dissipated in BLA will be transferred to the 70 K environment by a copper stub brazed directly to the absorbing ceramic ring. The stub holds the ring in a stainless steel vacuum chamber thermally isolated from the 2K region by a flexible bellows. In 2010 the wakefields excited by beam bunches down to 40 microns were calculated, and the related wake potential and frequency spectrum of HOMs evaluated. The absorbing material (CA137 of Ceradyne Enterprice

  6. IFMIF accelerators design

    International Nuclear Information System (INIS)

    Mosnier, A.; Ratzinger, U.

    2008-01-01

    The IFMIF requirement for 250 mA current of deuteron beams at a nominal energy of 40 MeV is met by means of two identical continuous wave (CW) 175 MHz linear accelerators running in parallel, each delivering a 125 mA, 40 MeV deuteron beam to the common target. This approach allows to stay within the current capability of present RF linac technology while providing operational redundancy in case of failure of one of the linacs. Each linac comprises a sequence of acceleration and beam transport/matching stages. The ion source generates a 140 mA deuteron beam at 100 keV. A low energy beam transport (LEBT) transfers the deuteron beam from the source to a radio frequency quadrupole (RFQ) cavity. The RFQ bunches and accelerates the 125 mA beam to 5 MeV. The RFQ output beam is injected through a matching section into a drift-tube-linac (DTL) where it is accelerated to the final energy of 40 MeV. In the reference design, the final acceleration stage is a conventional Alvarez-type DTL with post-couplers operating at room temperature. Operation of both the RFQ and the DTL at the same relatively low frequency is essential for accelerating the high current deuteron beam with low beam loss. The primary concern of the IFMIF linacs is the minimization of beam losses, which could limit their availability and maintainability due to excessive activation of the linac and irradiation of the environment. A careful beam dynamics design is therefore needed from the source to the target to avoid the formation of particle halo that could finally be lost in the linac or transfer lines. A superconducting solution for the high energy portion of the linac using, for example, CH-structure or coaxial-type resonators, could offer some advantages, in particular the reduction of operational costs. Careful beam dynamics simulations and comparison tests with beam during the EVEDA phase are however necessary in order to fully assess the technical feasibility of such alternative solutions

  7. Design of photonic phased array switches using nano electromechanical systems on silicon-on-insulator integration platform

    Science.gov (United States)

    Hussein, Ali Abdulsattar

    This thesis presents an introduction to the design and simulation of a novel class of integrated photonic phased array switch elements. The main objective is to use nano-electromechanical (NEMS) based phase shifters of cascaded under-etched slot nanowires that are compact in size and require a small amount of power to operate them. The structure of the switch elements is organized such that it brings the phase shifting elements to the exterior sides of the photonic circuits. The transition slot couplers, used to interconnect the phase shifters, are designed to enable biasing one of the silicon beams of each phase shifter from an electrode located at the side of the phase shifter. The other silicon beam of each phase shifter is biased through the rest of the silicon structure of the switch element, which is taken as a ground. Phased array switch elements ranging from 2x2 up to 8x8 multiple-inputs/multiple-outputs (MIMO) are conveniently designed within reasonable footprints native to the current fabrication technologies. Chapter one presents the general layout of the various designs of the switch elements and demonstrates their novel features. This demonstration will show how waveguide disturbances in the interconnecting network from conventional switch elements can be avoided by adopting an innovative design. Some possible applications for the designed switch elements of different sizes and topologies are indicated throughout the chapter. Chapter two presents the design of the multimode interference (MMI) couplers used in the switch elements as splitters, combiners and waveguide crossovers. Simulation data and design methodologies for the multimode couplers of interest are detailed in this chapter. Chapter three presents the design and analysis of the NEMS-operated phase shifters. Both simulations and numerical analysis are utilized in the design of a 0°-180° capable NEMS-operated phase shifter. Additionally, the response of some of the designed photonic phased

  8. Design Methodology - Design Synthesis

    DEFF Research Database (Denmark)

    Andreasen, Mogens Myrup

    2003-01-01

    Design Methodology is part of our practice and our knowledge about designing, and it has been strongly supported by the establishing and work of a design research community. The aim of this article is to broaden the reader¿s view of designing and Design Methodology. This is done by sketching...... the development of Design Methodology through time and sketching some important approaches and methods. The development is mainly forced by changing industrial condition, by the growth of IT support for designing, but also by the growth of insight into designing created by design researchers.......ABSTRACT Design Methodology shall be seen as our understanding of how to design; it is an early (emerging late 60ies) and original articulation of teachable and learnable methodics. The insight is based upon two sources: the nature of the designed artefacts and the nature of human designing. Today...

  9. Status of higher order mode beam position monitors in 3.9 GHz superconducting accelerating cavities at FLASH

    CERN Document Server

    Zhang, P; Jones, R M; Flisgen, T; Van Rienen, U; Shinton, I R R

    2013-01-01

    Higher order mode (HOM) beam position monitors (BPM) are being developed for the 3.9 GHz third harmonic superconducting accelerating cavities at FLASH. The transverse beam position in a cavity can be determined utilizing beam-excited HOMs based on dipole components. The existing couplers used for HOM suppression provide necessary signals. The diagnostics principle is similar to a cavity BPM, but requires no additional vacuum instruments on the linac. The challenges of HOM-BPM for 3.9 GHz cavities lie in the dense HOM spectrum arising from the coupling of the majority HOMs amongst the four cavities in the cryo-module ACC39. HOMs with particularly promising diagnostics features were evaluated using a spectrum analyzer and custom-built test electronics with various data analysis techniques, data reduction was focused on. After careful theoretical and experimental assessment of the HOM spectrum, multi-cavity modes in the region of 5 GHz were chosen to provide a global position over the complete module with superi...

  10. Design of ultra compact polarization splitter based on complete photonic band gap

    Science.gov (United States)

    Sinha, R. K.; Nagpal, Yogita

    2005-11-01

    Certain select structures in photonic crystals (PhCs) exhibit complete photonic band gap i.e. a frequency region where the photonic band gaps for both polarizations (i.e. transverse electric and transverse magnetic modes) exist and overlap. One of the most fundamental applications of the photonic band gap structures is the design of photonic crystal waveguides, which can be made by inserting linear defects in the photonic crystal structures. By setting closely two parallel 2D PhC waveguides, a directional waveguide coupler can be designed, which can be used to design a polarization splitter. In this paper we design a polarization splitter in a photonic crystal structure composed of two dimensional honeycomb pattern of dielectric rods in air. This photonic crystal structure exhibits a complete photonic band gap that extends from λ = 1.49 μm to λ = 1.61 μm, where lambda is the wavelength in free space, providing a large bandwidth of 120 nm. A polarization splitter can be made by designing a polarization selective coupler. The coupling lengths at various wavelengths for both polarizations have been calculated using the Finite Difference Time Domain method. It has been shown that the coupling length, for TE polarization is much smaller as compared to that for the TM polarization. This principle is used to design a polarization splitter of length 32 μm at λ = 1.55 μm. Further, the spectral response of the extinction ratios for both polarizations in the two waveguides at propagation distance of 32 μm has been studied.

  11. Designing Material Materialising Design

    DEFF Research Database (Denmark)

    Nicholas, Paul

    2013-01-01

    Designing Material Materialising Design documents five projects developed at the Centre for Information Technology and Architecture (CITA) at the Royal Danish Academy of Fine Arts, School of Architecture. These projects explore the idea that new designed materials might require new design methods....... Focusing on fibre reinforced composites, this book sustains an exploration into the design and making of elastically tailored architectural structures that rely on the use of computational design to predict sensitive interdependencies between geometry and behaviour. Developing novel concepts...

  12. Comentario sobre el libro de Enric Saguer Hom, Gabriel Jover Avellà y Helena Benito Mundet (eds.: Comtes de senyor, comtes de pagès. Les comptabilitats agràries en la historia rural. Associació d'Història Rural de les Comarques Gironines. Centre de Recerca Històrica Rural (Institut de Recerca Històrica de la Universitat de Girona i Documenta Universitaria (Biblioteca d'Història Rural, col·lecció Fonts, 7, Girona, 2013

    Directory of Open Access Journals (Sweden)

    Gaspar Feliu

    2014-07-01

    Full Text Available Comentario sobre el libro de Enric Saguer Hom, Gabriel Jover Avellà y Helena Benito Mundet (eds.: Comtes de senyor, comtes de pagès. Les comptabilitats agràries en la historia rural. Associació d'Història Rural de les Comarques Gironines. Centre de Recerca Històrica Rural (Institut de Recerca Històrica de la Universitat de Girona i Documenta Universitaria (Biblioteca d'Història Rural, col·lecció Fonts, 7, Girona, 2013

  13. Design approach for the development of a cryomodule for compact crab cavities for Hi-Lumi LHC

    Science.gov (United States)

    Pattalwar, Shrikant; Jones, Thomas; Templeton, Niklas; Goudket, Philippe; McIntosh, Peter; Wheelhouse, Alan; Burt, Graeme; Hall, Ben; Wright, Loren; Peterson, Tom

    2014-01-01

    A prototype Superconducting RF (SRF) cryomodule, comprising multiple compact crab cavities is foreseen to realise a local crab crossing scheme for the "Hi-Lumi LHC", a project launched by CERN to increase the luminosity performance of LHC. A cryomodule with two cavities will be initially installed and tested on the SPS drive accelerator at CERN to evaluate performance with high-intensity proton beams. A series of boundary conditions influence the design of the cryomodule prototype, arising from; the complexity of the cavity design, the requirement for multiple RF couplers, the close proximity to the second LHC beam pipe and the tight space constraints in the SPS and LHC tunnels. As a result, the design of the helium vessel and the cryomodule has become extremely challenging. This paper assesses some of the critical cryogenic and engineering design requirements and describes an optimised cryomodule solution for the evaluation tests on SPS.

  14. A prototype superconducting cavity for TRISTAN

    International Nuclear Information System (INIS)

    Furuya, T.; Hara, K.; Hosoyama, K.

    1987-01-01

    Following the feasibility study on the 3-cell superconducting cavity in the TRISTAN Accumulation Ring (TAR), a 5-cell 508 MHz Nb cavity was constructed and tested in the TAR. The cavity was equipped with a RF input coupler on a beam pipe, two HOM couplers on the other beam pipe and two additional HOM couplers on the equator of an end cell. The maximum accelerating field (Eaxx) was 4.5 MV/m with a Q value of about 1x10 9 at 4.2 deg K. The field was limited by the electron field emission and neither electron multipacting nor breakdown caused by couplers was observed. Damping of the HOM was sufficient and the input coupler was tested up to 82 KW in total reflection. A frequency tuning system consisted of two piezo electric and mechanical tuners. The piezo tuner was fast enough and the mechanical tuner covered wide range. In the beam test, the single bunch electron current of 29 mA was captured by the superconducting cavity alone and 13 mA was accelerated to 4.8 GeV. The maximum power transferred to the beam was 26 KW. The refrigeration system worked very stably

  15. Designing Communication Design

    DEFF Research Database (Denmark)

    Løvlie, Anders Sundnes

    2016-01-01

    Innovating in the field of new media genres requires methods for producing designs that can succeed in being disseminated and used outside of design research labs. This article uses the author's experiences with the development of university courses in communication design to address the research...... question: How can we design courses to give students the competencies they need to work as designers of new media? Based on existing approaches from UX design and other fields, I present a model that has demonstrated its usefulness in the development of commercial products and services. The model...

  16. Linear collider RF structure design using ARGUS

    International Nuclear Information System (INIS)

    Kwok Ko

    1991-01-01

    In a linear collider, both the driving system (klystrons) and the accelerating system (linac) consists of RF structures that are inherently three-dimensional. These structures which are responsible for power input/output, have to satisfy many requirements in order that instabilities, beam or RF related, are to be avoided. At the same time, system efficiencies have to be maintained at optimal to minimize cost. Theoretical analysis on these geometrically complex structures are difficult and until recently, numerical solutions have been limited. At SLAC, there has been a continuing and close collaboration among accelerator physicists, engineers and numericists to integrate supercomputing into the design procedure which involves 3-D RF structures. The outcome is very encouraging. Using the 3-D/electromagnetic code ARGUS (developed by SAIC) on the Cray computers at NERSC in conjunction with supporting theories, a wide variety of critical components have been simulated and evaluated. Aside from structures related to the linear collider, the list also includes the RF cavity for the proposed Boson Factory and the anode circuit for the Cross-Field Amplifier, once considered as an alternative to the klystron as a possible power source. This presentation will focus on two specific structures: (1) the klystron output cavity; and (2) the linac input coupler. As the results demonstrate, supercomputing is fast becoming a viable technology that could conceivably replace actual cold-testing in the near future

  17. A new way to design four-bar linkages with Coupler-points, tracing approximate straight-lines with or without an unvariable speed (a local kinematic theory to replace gear-wheels)

    NARCIS (Netherlands)

    Dijksman, E.A.; Hervé, J.M.

    1992-01-01

    Algebraieally expressing the derivatives of the transmission-ratio of the four-bar into the inverse of the tangents of the so-called cOllineation-angles, enables the grounding of an entirely new approach to 3rd order instantaneous kinematies. As aresuIt, the Carter-Hall circle appeared as a handy

  18. Annexe 3. Constitution d'une exploitation à Homs

    OpenAIRE

    2015-01-01

    ‘Abd al-Laṭīf, né en 1925, est jardinier à Horns. Il exploite avec son fils aîné et l'aide de deux de ses petits-fils un jardin de quelques 35 dunum (3,5 hectares) situé dans le zūr al-Ǧdīdeh, secteur central de la zone agricole. Cette grande exploitation, constituée de plusieurs parcelles ayant différents statuts, est en partie le produit d'une histoire familiale dont je voudrais présenter ici brièvement les principaux aspects. Figure 50 – Alliances matrimoniales entre la lignée de ‘Abbās e...

  19. Effect of gamma irradiation on Hom Tong banana

    International Nuclear Information System (INIS)

    1971-01-01

    This report contains research on the use of gamma irradiation to retard the ripening and extend the shelf life of bananas. The major concerns were the effects that irradiation would have on the nutritional content, the organoleptic properties and the pigment of the fruit

  20. A Descoberta da Morte e Mundo Homérico

    Directory of Open Access Journals (Sweden)

    Linneu Camargo Schutzer

    1956-11-01

    Full Text Available A insistência com que os historiadores da filosofia apresentam o mundo grego a partir do naturalismo jônio, com breves referências ao pensamento helênico anterior, leva-nos algumas vêzes a aceitar a ordem natural como a primeira sugestão para um pensamento racional, nela procurando a própria origem da noção de devir.

  1. Remoção da cartilagem articular associada ou não a implante homógeno ou enxerto autógeno de osso esponjoso em cães submetidos à artrodese atlantoaxial Joint cartilage removal associated or not to homologous implant or autologous cancellous bone graft in dogs submitted to atlantoaxial arthrodesis

    Directory of Open Access Journals (Sweden)

    Rafael Festugatto

    2013-03-01

    Full Text Available O objetivo deste estudo foi avaliar o grau de fusão articular e formação óssea na articulação atlantoaxial de cães submetidos à artrodese após a remoção da cartilagem articular associada ou não ao implante homógeno ou enxerto autógeno de osso esponjoso. Foram utilizados 12 cães, adultos, distribuídos aleatoriamente em três grupos iguais. Grupo I (GI: realizada apenas a remoção da cartilagem articular e imobilização articular com pinos e resina acrílica. Grupo II (GII: feita a remoção da cartilagem articular e imobilização da articulação, seguida da colocação e modelagem do implante ósseo esponjoso homógeno entre as superfícies articulares. Grupo III (GIII: foi realizado o mesmo procedimento do GII, mais o enxerto ósseo esponjoso autógeno no local determinado. Realizaram-se exames radiográficos em todos os animais aos 30, 60 e 90 dias de pós-operatório (PO. Aos 90 dias de PO foi feita a eutanásia para o emprego do teste de palpação manual, avaliação tomográfica e histopatológica. Para análise estatística da associação entre o grau de fusão articular, aplicou-se o Teste Qui-quadrado de independência. Os resultados dos testes foram avaliados pela significância exata e considerados significantes a 5% (PThe aim of this study was to evaluate the degree of joint fusion and bone formation in dogs undergoing atlantoaxial arthrodesis after removal of articular cartilage associated or not to implant homogenous or autogenous cancellous bone. Twelve dogs, weighing between 8 and 12kg were randomly divided into three groups. Group I (GI performed only the removal of joint cartilage and joint immobilization with acrylic resin and pins. Group II (GII: after removel of joint cartilage and articular immobilization was performed modeling and placement of homogenous cancellous bone at the given location. The volume of homograft placed in the joint was measured using a precision balance and all animals received the

  2. Design of 6 MeV X-band electron linac for dual-head gantry radiotherapy system

    Science.gov (United States)

    Shin, Seung-wook; Lee, Seung-Hyun; Lee, Jong-Chul; Kim, Huisu; Ha, Donghyup; Ghergherehchi, Mitra; Chai, Jongseo; Lee, Byung-no; Chae, Moonsik

    2017-12-01

    A compact 6 MeV electron linac is being developed at Sungkyunkwan University, in collaboration with the Korea atomic energy research institute (KAERI). The linac will be used as an X-ray source for a dual-head gantry radiotherapy system. X-band technology has been employed to satisfy the size requirement of the dual-head gantry radiotherapy machine. Among the several options available, we selected a pi/2-mode, standing-wave, side-coupled cavity. This choice of radiofrequency (RF) cavity design is intended to enhance the shunt impedance of each cavity in the linac. An optimum structure of the RF cavity with a high-performance design was determined by applying a genetic algorithm during the optimization procedure. This paper describes the detailed design process for a single normal RF cavity and the entire structure, including the RF power coupler and coupling cavity, as well as the beam dynamics results.

  3. On the “Cracking” Scheme in the Paper “A Directional Coupler Attack Against the Kish Key Distribution System” by Gunn, Allison and Abbott

    Directory of Open Access Journals (Sweden)

    Chen Hsien-Pu

    2014-08-01

    Full Text Available Recently, Gunn, Allison and Abbott (GAA [http://arxiv.org/pdf/1402.2709v2.pdf] proposed a new scheme to utilize electromagnetic waves for eavesdropping on the Kirchhoff-law-Johnson-noise (KLJN secure key distribution. We proved in a former paper [Fluct. Noise Lett. 13 (2014 1450016] that GAA’s mathematical model is unphysical. Here we analyze GAA’s cracking scheme and show that, in the case of a loss-free cable, it provides less eavesdropping information than in the earlier (Bergou-Scheuer-Yariv mean-square-based attack [Kish LB, Scheuer J, Phys. Lett. A 374:2140-2142 (2010], while it offers no information in the case of a lossy cable. We also investigate GAA’s claim to be experimentally capable of distinguishing—using statistics over a few correlation times only—the distributions of two Gaussian noises with a relative variance difference of less than 10-8. Normally such distinctions would require hundreds of millions of correlations times to be observable. We identify several potential experimental artifacts as results of poor KLJN design, which can lead to GAA’s assertions: deterministic currents due to spurious harmonic components caused by ground loops, DC offset, aliasing, non-Gaussian features including non-linearities and other non-idealities in generators, and the timederivative nature of GAA’s scheme which tends to enhance all of these artifacts.

  4. Prompting Designers to Design

    DEFF Research Database (Denmark)

    Ahmed, Saeema

    2006-01-01

    Recent research suggest that engineering designers need assistance to understand what information is relevant for their particular design problem. They require guidance in formulating their queries and also to understand what information is relevant for them. This paper presents an approach to pr...

  5. Design and Application of SCADA Based Control System for filling process (Inter facing and Monitoring)

    International Nuclear Information System (INIS)

    Aung Naing Myint; Maung Maung Latt; Win Khaing Moe; Theingi

    2008-06-01

    In a small SCADA system, using industrial standard components and simulating real world applications, designs and constructs for thesis to interface between automation devices and software. It programs PIC microcontroller that need the information to write the sequence of process that flowchart like the PIC ladder-logic programs that control the equipment in system, software integrators to be required the information for the configuration screens and hardware installers which need the information to install and connect the equipment. It uses the initiating processor's multiplexer to verify that data or signals are being transmitted out of the parallel port and includes auto-coupler to divide different voltages between circuits and computer. Existing SCADA system are divisible into two groups - cheap and inflexible control, and another one is expensive but flexible control. This thesis attempted by means of using other network for SCADA communications and simple for control, both of which maintain flexibility while reducing cost

  6. Design of a low emittance and high repetition rate S-band photoinjector

    Science.gov (United States)

    Han, Jang-Hui

    2014-09-01

    As an electron beam injector of X-ray free-electron lasers (FELs), photoinjectors have been developed for the past few decades. Such an injector starting with a photocathode RF gun provides high brightness beams and therefore it is being adopted as an injector of X-ray FELs. In this paper we show how to improve photoinjector performance in terms of emittance and repetition rates by means of injector components optimization, especially with the gun. Transverse emittance at the end of an injector is reduced by optimizing the gun design, gun solenoid position, and accelerating section position. The repetition rate of an injector mainly depends on the gun. It is discussed that a repetition rate of 1 kHz at a normal-conducting S-band photoinjector is feasible by adopting a coaxial RF coupler and improving cooling-water channels surrounding the gun.

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

    Indian Academy of Sciences (India)

    ... CW klystron followed by wave-guide filter, dual directional coupler, high-power circulator, three 3 dB magic TEE power dividers to split the main channel into four equal channels of 250 kW each. Each individual channel has dual directional couplers, flexible wave-guide sections and high power ceramic vacuum window.

  8. Pino ósseo homólogo conservado em glicerina a 98% e hemicerclagem com fio poliglactina 910 na osteossíntese umeral de pombos domésticos Homologous bone pin conserved in glycerin at 98% and hemicerclagem with a thread of poliglactina 910 in humerus osteosyntesis of domestic pigeons

    Directory of Open Access Journals (Sweden)

    Juliano Bolson

    2008-10-01

    Full Text Available O objetivo do presente estudo foi avaliar a utilização de um pino intramedular ósseo homólogo, conservado em glicerina a 98%, associado à hemicerclagem com fio poliglactina 910 na osteossíntese umeral transversa de pombos domésticos (Columba livia. Utilizou-se como pino ósseo a parte distal do tibiotarso, conservado com medula óssea. Foram operados 20 pombos domésticos, adultos, não-sexados e clinicamente sadios. Esses animais foram separados ao acaso em cinco grupos, com quatro indivíduos. O úmero foi seccionado cirurgicamente na sua diáfise, de forma transversa, e o pino ósseo foi devidamente implantado no seio do osso. Orifícios foram realizados e por eles procedeu-se hemicerclagem do tipo pontos de Wolff com poliglactina 910. Os animais foram avaliados clinicamente, por meio de radiografias semanais, e histologicamente após os períodos de 15, 30, 60, 90 e 120 dias. A conservação do pino ósseo em glicerina a 98% foi avaliada por meio de exames microbiológicos. Em todos os animais, pode-se notar, clinicamente, excelente adaptação à cirurgia e normalidade do uso do membro já radiologicamente pode-se observar formação de calo ósseo e cicatrização da fratura. Histologicamente pode-se observar que ocorreu formação de calo ósseo 15 dias após a cirurgia e cicatrização com remodelação completa a partir dos 90 dias. Nesse exame, além de leve a moderada reação inflamatória no período inicial de avaliação, nenhum outro evento foi notado nos períodos subseqüentes. Concluiu-se que a técnica e os materiais utilizados se tornam uma opção altamente viável na osteossíntese umeral transversa de pombos domésticos.The objective of the present study was to evaluate the use of a homologous bone intramedullary pin, conserved in glycerin at 98% associated to hemicerclage with a thread of polyglactina 910 in the transverse humerus osteosynthesis of domestic pigeon (Columba livia. The distal part of the

  9. Reparação traqueal em cães: transplante autógeno vs implante homógeno conservado em glicerina a 98% de cartilagem da pina Tracheal healing in dogs: autograft versus homograft implant preserved in 98% glycerin of pinna cartilage

    Directory of Open Access Journals (Sweden)

    Emerson Antonio Contesini

    2001-08-01

    Full Text Available Diversas patologias acometem a traquéia dos animais domésticos de forma a comprometer o fluxo respiratório, inclusive a sobrevivência do animal. Obstrução por corpo estranho ou neoplasias, rupturas traumáticas, colapso e estenose são tidas como as principais. Reparações de defeitos induzidos experimentalmente em traquéias de 12 cães foram testadas comparativamente com o emprego de retalho de cartilagem da pina autógena em 6 cães (grupo I e homógena conservada em glicerina a 98% nos demais (grupo II. Para tal, removeu-se um terço da circunferência de três anéis da traquéia cervical. Esses animais permaneceram durante um período de 30 e 45 dias sob observação e avaliação clínica em descanso e exercício físico moderado, sem apresentar quaisquer complicações decorrentes da cirurgia. Ao final desse período, o segmento traqueal operado foi submetido à avaliação macro e microscópica, sendo observado macroscopicamente, encobrimento completo do retalho por uma estrutura delgada e esbranquiçada em todos os animais. A análise microscópica da região transplantada do grupo I revelou que a mesma foi invadida por tecido de granulação, a lâmina própria apresentou moderada infiltração de neutrófilos e pouca fibrose com focos de hiperplasia epitelial. Nos animais do grupo II, foram observadas, na região do implante, além disso, discreta invasão de macrófagos e vasos neoformados, com inflamação moderada na lâmina própria, e epitélio sem alteração. Essas observações sugerem que o implante de cartilagem da pina conservada em glicerina a 98%, induz resposta menos agressiva pelo leito receptor, embora isso não seja evidenciado macroscopicamente.Several patologies affect the trachea, compromising the respiratory stream and the animal survival. Foreign bodies, neoplasm, ruptures, collapse and stricture are the most common ones. The effects of canine pinna cartilage implantation were evaluated in 12 dogs. Six of

  10. Standardization of Schwarz-Christoffel transformation for engineering design of semiconductor and hybrid integrated-circuit elements

    Science.gov (United States)

    Yashin, A. A.

    1985-04-01

    A semiconductor or hybrid structure into a calculable two-dimensional region mapped by the Schwarz-Christoffel transformation and a universal algorithm can be constructed on the basis of Maxwell's electro-magnetic-thermal similarity principle for engineering design of integrated-circuit elements. The design procedure involves conformal mapping of the original region into a polygon and then the latter into a rectangle with uniform field distribution, where conductances and capacitances are calculated, using tabulated standard mapping functions. Subsequent synthesis of a device requires inverse conformal mapping. Devices adaptable as integrated-circuit elements are high-resistance film resistors with periodic serration, distributed-resistance film attenuators with high transformation ratio, coplanar microstrip lines, bipolar transistors, directional couplers with distributed coupling to microstrip lines for microwave bulk devices, and quasirregular smooth matching transitions from asymmetric to coplanar microstrip lines.

  11. Winged design; Befluegeltes Design

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Tilman

    2013-10-15

    Today the wind rotor blades are about 80 meter long. To keep them light and transportable designers and material scientists come up with a number of ideas. Will the carbon fiber prevail against the glass fiber? [German] Ueber 80 Meter messen die laengsten Rotorblaetter heute. Um sie leicht und transportfaehig zu halten, lassen sich Designer und Materialforscher einiges einfallen. Wird sich die Kohlefaser gegen die Glasfaser durchsetzen?.

  12. Mechanical design of 56 MHz superconducting RF cavity for RHIC collider

    Energy Technology Data Exchange (ETDEWEB)

    Pai, C.; Ben-Zvi, I.; Burrill, A.; Chang, X.; McIntyre, G.; Than, Y.; Tuozzolo, J.; Wu, Q.

    2011-03-28

    A 56 MHz Superconducting RF Cavity operating at 4.4K is being constructed for the RHIC collider. This cavity is a quarter wave resonator with beam transmission along the centerline. This cavity will increase collision luminosity by providing a large longitudinal bucket for stored bunches of RHIC ion beam. The major components of this assembly are the niobium cavity with the mechanical tuner, its titanium helium vessel and vacuum cryostat, the support system, and the ports for HOM and fundamental dampers. The cavity and its helium vessel must meet equivalent safety with the ASME pressure vessel code and it must not be sensitive to frequency shift due to pressure fluctuations from the helium supply system. Frequency tuning achieved by a two stage mechanical tuner is required to meet performance parameters. This tuner mechanism pushes and pulls the tuning plate in the gap of niobium cavity. The tuner mechanism has two separate drive systems to provide both coarse and fine tuning capabilities. This paper discusses the design detail and how the design requirements are met.

  13. Design of a higher harmonic RF system for the Advanced Light Source

    CERN Document Server

    Byrd, J M; De Santis, S; Kosta, S; Lo, C C; Plate, D; Rimmer, R A; Franks, M

    2000-01-01

    We report on the design and fabrication of a third harmonic radiofrequency (RF) system for the Advanced Light Source (ALS) to be used for lengthening the bunch and increasing the Touschek-dominated beam lifetime. We plan to install five single-cell 1.5 GHz copper RF cavities in one-half of an ALS straight section with a predicted increase in the lifetime by a factor of 3. Each RF cell is designed to sustain a maximum voltage of 125 kV with a power dissipation of 5 kW. We present measurements made on an aluminum cavity model characterizing the RF properties of cavity such as the cavity R/Q and higher-order modes (HOMs). In particular, resonances in the cavity tuners were studied in order to avoid heating of the tuner bellows. Initial measurements of the copper cavities indicate a Q value of 21 000, resulting in a shunt impedance of 1.69 M OMEGA per cell

  14. Dansk Design

    DEFF Research Database (Denmark)

    Dickson, Thomas

    Indhold: Hvad er design?; Hvor kommer dansk design fra?; Produktdesign; Tekstil- og tøjdesign; Design af møbler og boligindretning; Bygningen og design; Arbejdets design; Transportdesign; Offentligt design; Grafisk design; Nye tider og en ny slags design...

  15. Multipactor Simulations of the SPL Power Coupler

    CERN Document Server

    Burt, A; Dexter, A C; Calaga, R; Montesinos, E; Author, F; Author, G

    2010-01-01

    Mul­ti­pactor is a lim­it­ing fac­tor in many RF power cou­plers. The SPL cou­pler is pro­posed to have a con­i­cal match­ing sec­tion be­tween the win­dow and the coax­i­al sec­tion how­ev­er this sec­tion must be checked for mul­ti­pactor. Mul­ti­pactor sim­u­la­tions of the cou­pler up to a few MW's of power were per­formed using a va­ri­ety of dif­fer­ent codes and the re­sults were com­pared. Sim­u­la­tions were per­formed in the con­i­cal and straight coax­i­al sec­tions.

  16. Coupler for surgery on small animals

    Science.gov (United States)

    Johnson, J. E., Jr.; Swartz, P. F.

    1979-01-01

    Minicoupler simplifies exchange of fluids with organs of laboratory animals enabling one person to perform surgery on experimental animals such as rats and mice. Innovation eliminates obstructing hands and instruments from areas of surgery.

  17. Design of the 3.7 GHz, 500 kW CW circulator for the LHCD system of the SST-1 tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Dixit, Harish V., E-mail: hvdixit48@yahoo.com [Veermata Jijabai Technological Institute, Mumbai, Maharashtra 400019 (India); Jadhav, Aviraj R. [Veermata Jijabai Technological Institute, Mumbai, Maharashtra 400019 (India); Jain, Yogesh M. [Institute for Plasma Research, Gandhinagar, Gujarat 382428 (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094 (India); Cheeran, Alice N. [Veermata Jijabai Technological Institute, Mumbai, Maharashtra 400019 (India); Gupta, Vikas [Vidyavardhini' s College of Engineering and Technology, Vasai, Maharashtra 401202 (India); Sharma, P.K. [Institute for Plasma Research, Gandhinagar, Gujarat 382428 (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094 (India)

    2017-06-15

    Highlights: • Design of a 500 kW CW circulator for LHCD system at 3.7 GHz. • Mechanism for thermal management of ferrite tile. • Scheme for uniform magnetisation of the ferrite tiles. • Design of high CW power CW quadrature and 180 ° hybrid coupler. - Abstract: Circulators are used in high power microwave systems to protect the vacuum source against reflection. The Lower Hybrid Current Drive (LHCD) system of SST-1 tokamak commissioned at IPR, Gandhinagar in India comprises of four high power circulators to protect klystrons (supplying 500 kW CW each at 3.7 GHz) which power the system. This paper presents the design of a Differential Phase Shift Circulator (DPSC) capable of handling 500 kW CW power at 3.7 GHz so that four circulators can be used to protect the four available klystrons. As the DPSC is composed by three main components, viz., magic tee, ferrite phase shifter and 3 dB hybrid coupler, the designing of each of the proposed components is described. The design of these components is carried out factoring various multiphysics aspects of RF, heating due to high CW power and magnetic field requirement of the ferrite phase shifter. The primary objective of this paper is to present the complete RF, magnetic and thermal design of a high CW power circulator. All the simulations have been carried out in COMSOL Multiphysics. The designed circulator exhibits an insertion loss of 0.13 dB with a worst case VSWR of 1.08:1. The total length of the circulator is 3 m.

  18. A Thermally Tunable 1 × 4 Channel Wavelength Demultiplexer Designed on a Low-Loss Si3N4 Waveguide Platform

    Directory of Open Access Journals (Sweden)

    Mohammed Shafiqul Hai

    2015-11-01

    Full Text Available A thermally tunable 1 × 4 channel optical demultiplexer was designed using an ultra low-loss Si3N4 (propagation loss ~3.1 dB/m waveguide. The demultiplexer has three 2 × 2 Mach-Zehnder interferometers (MZI, where each of the MZI contains two 2 × 2 general interference based multimode interference (MMI couplers. The MMI couplers exhibit −3.3 dB to −3.7 dB power division ratios over a 50 nm wavelength range from 1530 nm to 1580 nm. The chrome-based (Cr heaters placed on the delay arms of the MZI filters enable thermal tuning to control the optical phase shift in the MZI delay arms. This facilitates achieving moderately low crosstalk (14.5 dB between the adjacent channels. The optical insertion loss of the demultiplexer per channel is between 1.5 dB to 2.2 dB over the 1550 nm to 1565 nm wavelength range. Error free performance (BER of 10−12 is obtained for all four 40 Gb/s data rate channels. The optical demultiplexer is an important tool towards building photonic integrated circuits with complex optical signal processing functionalities in the low-loss Si3N4 waveguide platform.

  19. Engineering, design and prototype tests of a 3.9 GHz transverse-mode superconducting cavity for a radiofrequency-separated kaon beam

    International Nuclear Information System (INIS)

    Mark S. Champion et al.

    2001-01-01

    A research and development program is underway to construct superconducting cavities to be used for radiofrequency separation of a Kaon beam at Fermilab. The design calls for installation of twelve 13-cell cavities operating in the 3.9 GHz transverse mode with a deflection gradient of 5 MV/m. They present the mechanical, cryogenic and vacuum design of the cavity, cryomodule, rf power coupler, cold tuner and supporting hardware. The electromagnetic design of the cavity is presented in a companion paper by Wanzenberg and McAshan. The warm tuning system (for field flatness) and the vertical test system is presented along with test results of bench measurements and cold tests on single-cell and five-cell prototypes

  20. Design of RF system for CYCIAE-230 superconducting cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Zhiguo, E-mail: bitbearAT@hotmail.com; Ji, Bin; Fu, Xiaoliang; Cao, Xuelong; Zhao, Zhenlu; Zhang, Tinajue

    2017-05-11

    The CYCIAE230 is a low-current, compact superconducting cyclotron designed for proton therapy. The Radio Frequency system consists of four RF cavities and applies second harmonic to accelerate beams. The driving power for the cavity system is estimated to be approximately 150 kW. The LLRF controller is a self-made device developed and tested at low power using a small-scale cavity model. In this paper, the resonator systems of an S.C. cyclotron in history are reviewed. Contrary to those RF systems, the cavities of the CYCIAE230 cyclotron connect two opposite dees. Two high-power RF windows are included in the system. Each window carries approximately 75 kW RF power from the driver to the cavities. Thus, the RF system for the CY-CIAE230 cyclotron is operated in driven push–pull mode. The two-way amplifier-coupler-cavity systems are operated with approximately the same amount of RF power but 180° out of phase compared with each other. The design, as well as the technical advantage and limitations of this operating mode, of the CYCIAE230 cyclotron RF system is analyzed.

  1. Design of RF system for CYCIAE-230 superconducting cyclotron

    Science.gov (United States)

    Yin, Zhiguo; Ji, Bin; Fu, Xiaoliang; Cao, Xuelong; Zhao, Zhenlu; Zhang, Tinajue

    2017-05-01

    The CYCIAE230 is a low-current, compact superconducting cyclotron designed for proton therapy. The Radio Frequency system consists of four RF cavities and applies second harmonic to accelerate beams. The driving power for the cavity system is estimated to be approximately 150 kW. The LLRF controller is a self-made device developed and tested at low power using a small-scale cavity model. In this paper, the resonator systems of an S.C. cyclotron in history are reviewed. Contrary to those RF systems, the cavities of the CYCIAE230 cyclotron connect two opposite dees. Two high-power RF windows are included in the system. Each window carries approximately 75 kW RF power from the driver to the cavities. Thus, the RF system for the CY-CIAE230 cyclotron is operated in driven push-pull mode. The two-way amplifier-coupler-cavity systems are operated with approximately the same amount of RF power but 180° out of phase compared with each other. The design, as well as the technical advantage and limitations of this operating mode, of the CYCIAE230 cyclotron RF system is analyzed.

  2. Design of a β=0.175 2-gap spoke resonator

    International Nuclear Information System (INIS)

    Krawczyk, F.L.; Chan, K.C.D.; Garnett, R.; Gentzlinger, R.; LaFave, R.P.; Kelley, J.P.; Schrage, D.L.; Tajima, T.; Roybal, P.L.

    2003-01-01

    In this paper, we present the electromagnetic and structural design of a low-β superconducting spoke resonator for a beam-test in the Low Energy Demonstration Accelerator (LEDA). This test is part of the Advanced Accelerator Applications (AAA) project. Recently, the sole use of superconducting resonators from 6.7 MeV on has been approved for this project. The beam test will use the lowest-β resonator from this accelerator design. The choices of the cavity dimensions are driven by its use immediately after the LEDA Radio-Frequency Quadrupole (RFQ). The frequency is 350 MHz, the length corresponds to a geometric β (β g ) of 0.175. Our design approach has been to carry out an integrated RF and mechanical design from the start. The final cavity is well understood in terms of RF and mechanical properties. The RF properties, like Q, R/Q, peak surface fields and acceleration efficiency are very reasonable for such a low-β structure. The design also includes power coupler, vacuum and pick-up ports and their influences. The mechanical design added tuning sensitivities, tuning forces, stiffening schemes and the understanding of stresses under various load conditions. This presentation reflects changes in the coupling port and the beam aperture compared to a previously presented design [1]. (author)

  3. Design automation for integrated nonlinear logic circuits (Conference Presentation)

    Science.gov (United States)

    Van Vaerenbergh, Thomas; Pelc, Jason; Santori, Charles; Bose, Ranojoy; Kielpinski, Dave; Beausoleil, Raymond G.

    2016-05-01

    A key enabler of the IT revolution of the late 20th century was the development of electronic design automation (EDA) tools allowing engineers to manage the complexity of electronic circuits with transistor counts now reaching into the billions. Recently, we have been developing large-scale nonlinear photonic integrated logic circuits for next generation all-optical information processing. At this time a sufficiently powerful EDA-style software tool chain to design this type of complex circuits does not yet exist. Here we describe a hierarchical approach to automating the design and validation of photonic integrated circuits, which can scale to several orders of magnitude higher complexity than the state of the art. Most photonic integrated circuits developed today consist of a small number of components, and only limited hierarchy. For example, a simple photonic transceiver may contain on the order of 10 building-block components, consisting of grating couplers for photonic I/O, modulators, and signal splitters/combiners. Because this is relatively easy to lay out by hand (or simple script) existing photonic design tools have relatively little automation in comparison to electronics tools. But demonstrating all-optical logic will require significantly more complex photonic circuits containing up to 1,000 components, hence becoming infeasible to design manually. Our design framework is based off Python-based software from Luceda Photonics which provides an environment to describe components, simulate their behavior, and export design files (GDS) to foundries for fabrication. At a fundamental level, a photonic component is described as a parametric cell (PCell) similarly to electronics design. PCells are described by geometric characteristics of their layout. A critical part of the design framework is the implementation of PCells as Python objects. PCell objects can then use inheritance to simplify design, and hierarchical designs can be made by creating composite

  4. Superstructure for high current applications in superconducting linear accelerators

    Science.gov (United States)

    Sekutowicz, Jacek [Elbchaussee, DE; Kneisel, Peter [Williamsburg, VA

    2008-03-18

    A superstructure for accelerating charged particles at relativistic speeds. The superstructure consists of two weakly coupled multi-cell subunits equipped with HOM couplers. A beam pipe connects the subunits and an HOM damper is included at the entrance and the exit of each of the subunits. A coupling device feeds rf power into the subunits. The subunits are constructed of niobium and maintained at cryogenic temperatures. The length of the beam pipe between the subunits is selected to provide synchronism between particles and rf fields in both subunits.

  5. Thermo mechanical design of normal-conducting deflecting cavities at the Advanced Photon Source for short x-ray pulse generation.

    Energy Technology Data Exchange (ETDEWEB)

    Brajuskovic, B.; Collins, J.; Den Hartog, P.; Morrison, L.; Waldschmidt, G.

    2008-01-01

    A normal-conducting deflecting cavity is being designed at the Advanced Photon Source (APS) as a part of the short x-ray pulse project intended to provide users with approximately 2 picosecond x-rays. The system will use two pairs of 3-cell cavities in sectors 6ID and 7ID for the generation of the x-ray pulse in the 7ID beamline. The 3-cell cavities are designed to provide the desired beam deflection while absorbing in excess of 4 kW of power from a pulsed rf system and up to 2.6 kW in the damper system of high-order mode (HOM) and low-order mode (LOM) waveguides. Since the cavity frequency is very sensitive to thermal expansion, the cooling water system is designed so that it is able to control cavity temperature to within 0.1 C. This paper describes the optimization of the thermomechanical design of the cavity based on calculation of thermal stresses and displacement caused by the generated heat loads, and presents the design of a cooling water system required for the proper operation of the cavities.

  6. Efeito da centrifugação e do líquido prostático homólogo na criopreservação de espermatozoides epididimários caninos Effect of centrifugation and homologous prostatic fluid on canine epydidimal spermatozoa cryopreservation

    Directory of Open Access Journals (Sweden)

    M.I.V. Melo

    2010-06-01

    Full Text Available Realizaram-se dois experimentos de criopreservação de espermatozoides epididimários caninos, investigando-se o efeito da centrifugação e da adição do líquido prostático sobre as características físicas do espermatozoide pós-descongelação. No experimento I, foi testado o efeito da centrifugação. As amostras congeladas sem centrifugação apresentaram pós-descongelação: motilidade total (MT de 26,7±21,2%, motilidade progressiva (MP de 21,2±20,1% e vigor espermático (V de 2,2±1,3, e as congeladas após a centrifugação: MT de 23,9±17,9%, MP de 20,6±17,4% e V de 2,2±1,0. No teste de termorresistência, o período médio de duração com MT mínima de 10% foi de 165±21,2 minutos sem centrifugação e de 77,5±63,6 minutos para as centrifugadas, indicando maior longevidade espermática das amostras não centrifugadas. No experimento II, foi avaliado o efeito da adição de líquido prostático homólogo no meio diluidor. As amostras congeladas sem líquido prostático no meio diluidor apresentaram MT de 13,3±13,1%, MP de 10,9±11,4% e V de 2,1±1,2, e as congeladas com líquido prostático MT de 14,1±12,6%, MP de 12,2±11,6% e V de 2,2±1,3. Os resultados sugerem que a centrifugação e a adição de 10% de líquido prostático ao diluidor não tiveram efeito sobre as características físicas do espermatozoide epididimário canino pós-descongelamento.The effect of centrifugation and the prostatic fluid addition were evaluated on the physical characteristics of the cryopreserved canine epydidimal spermatozoa. In the first experiment, the effect of centrifugation was analysed. The samples without centrifugation showed 26.7±21.2% of total motility (TM, 21.2±20.1% of progressive motility (PM, and 2.2±1.3 of intensity of movement (I. In addition, the samples after centrifugation showed 23.9±17.9% of TM, 20.6±17.4% of PM, and 2.2±1 of I. The mean time of samples duration, at least with 10% of total motility, was 165±21

  7. Membranas biológicas homólogas preservadas em solução alcalina seguida de liofilização, glicerina a 98% e por liofilização para implantação em eqüinos Homologous biological membranes persevered in alkaline solution and lyophilized, glycerin 98% and by lyophilization for equines implantation

    Directory of Open Access Journals (Sweden)

    Valcinir Aloisio Scolla Vulcani

    2008-08-01

    Full Text Available Objetivou-se, neste trabalho, avaliar as alterações físico-químicas proporcionadas pelo tratamento de centros tendinosos diafragmáticos homólogos em solução alcalina seguida de liofilização, para implantação na fáscia interna do músculo reto do abdome de eqüinos. As amostras foram tratadas em períodos de 24, 48, 72, 120 e 144 horas, liofilizadas e analisadas quanto à homogeneidade, flexibilidade e resistência à sutura das amostras. Posteriormente foram caracterizadas por calorimetria exploratória diferencial e microscopia eletrônica de varredura. Para a implantação nos eqüinos, foram utilizadas amostras tratadas por 72 horas seguidas de liofilização, amostras conservadas em glicerina 98% e amostras apenas liofilizadas, que foram retiradas após uma, nove e 18 semanas para avaliar a existência de aderências. Verificou-se que a homogeneidade e a flexibilidade são diretamente proporcionais ao aumento do tempo de tratamento em solução alcalina, enquanto que a resistência é inversamente proporcional ao aumento de tempo, sendo o tratamento por 72 horas intermediário para estas características. A calorimetria exploratória diferencial mostrou que o tratamento não desnatura o colágeno presente nas amostras. Na microscopia eletrônica de varredura, observou-se que o aumento de tempo de tratamento proporciona expansão de zonas menos densas do material. Em relação à formação de aderências, as amostras apenas liofilizadas apresentaram grau máximo na formação da classificação proposta, seguida pelas amostras conservadas em glicerina 98% com grau médio e as amostras tratadas em solução alcalina e liofilizadas, que foram classificadas em grau mínimo. Concluiu-se que o tratamento por 72 horas seria mais apropriado para implantação e que a integração tissular com a parede abdominal foi melhor em relação às amostras apenas liofilizadas e às conservadas em glicerina.The objectives in this research were

  8. Design principles and realization of electro-optical circuit boards

    Science.gov (United States)

    Betschon, Felix; Lamprecht, Tobias; Halter, Markus; Beyer, Stefan; Peterson, Harry

    2013-02-01

    The manufacturing of electro-optical circuit boards (EOCB) is based to a large extent on established technologies. First products with embedded polymer waveguides are currently produced in series. The range of applications within the sensor and data communication markets is growing with the increasing maturity level. EOCBs require design flows, processes and techniques similar to existing printed circuit board (PCB) manufacturing and appropriate for optical signal transmission. A key aspect is the precise and automated assembly of active and passive optical components to the optical waveguides which has to be supported by the technology. The design flow is described after a short introduction into the build-up of EOCBs and the motivation for the usage of this technology within the different application fields. Basis for the design of EOCBs are the required optical signal transmission properties. Thereafter, the devices for the electro-optical conversion are chosen and the optical coupling approach is defined. Then, the planar optical elements (waveguides, splitters, couplers) are designed and simulated. This phase already requires co-design of the optical and electrical domain using novel design flows. The actual integration of an optical system into a PCB is shown in the last part. The optical layer is thereby laminated to the purely electrical PCB using a conventional PCB-lamination process to form the EOCB. The precise alignment of the various electrical and optical layers is thereby essential. Electrical vias are then generated, penetrating also the optical layer, to connect the individual electrical layers. Finally, the board has to be tested electrically and optically.

  9. VLSI design

    CERN Document Server

    Chandrasetty, Vikram Arkalgud

    2011-01-01

    This book provides insight into the practical design of VLSI circuits. It is aimed at novice VLSI designers and other enthusiasts who would like to understand VLSI design flows. Coverage includes key concepts in CMOS digital design, design of DSP and communication blocks on FPGAs, ASIC front end and physical design, and analog and mixed signal design. The approach is designed to focus on practical implementation of key elements of the VLSI design process, in order to make the topic accessible to novices. The design concepts are demonstrated using software from Mathworks, Xilinx, Mentor Graphic

  10. Mechanical Design and Fabrication of a New RF Power Amplifier for LANSCE

    International Nuclear Information System (INIS)

    Chen, Zukun

    2011-01-01

    A Full-scale prototype of a new 201.25 MHz RF Final Power Amplifier (FPA) for Los Alamos Neutron Science Center (LANSCE) has been designed, fabricated, assembled and installed in the test facility. This prototype was successfully tested and met the physics and electronics design criteria. The team faced design and manufacturing challenges, having a goal to produce 2 MW peak power at 13% duty factor, at the elevation of over 2 km in Los Alamos. The mechanical design of the final power amplifier was built around a Thales TH628 Diacrode R , a state-of-art tetrode power tube. The main structure includes Input circuit, Output circuit, Grid decoupling circuit, Output coupler, Tuning pistons, and a cooling system. Many types of material were utilized to make this new RF amplifier. The fabrication processes of the key components were completed in the Prototype Fabrication Division shop at Los Alamos National Laboratory. The critical plating procedures were achieved by private industry. The FPA mass is nearly 600 kg and installed in a beam structural support stand. In this paper, we summarize the FPA design basis and fabrication, plating, and assembly process steps with necessary lifting and handling fixtures. In addition, to ensure the quality of the FPA support structure a finite element analysis with seismic design forces has also been carried out.

  11. Mechanical Design and Fabrication of a New RF Power Amplifier for LANSCE

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zukun [Los Alamos National Laboratory

    2011-01-01

    A Full-scale prototype of a new 201.25 MHz RF Final Power Amplifier (FPA) for Los Alamos Neutron Science Center (LANSCE) has been designed, fabricated, assembled and installed in the test facility. This prototype was successfully tested and met the physics and electronics design criteria. The team faced design and manufacturing challenges, having a goal to produce 2 MW peak power at 13% duty factor, at the elevation of over 2 km in Los Alamos. The mechanical design of the final power amplifier was built around a Thales TH628 Diacrode{sup R}, a state-of-art tetrode power tube. The main structure includes Input circuit, Output circuit, Grid decoupling circuit, Output coupler, Tuning pistons, and a cooling system. Many types of material were utilized to make this new RF amplifier. The fabrication processes of the key components were completed in the Prototype Fabrication Division shop at Los Alamos National Laboratory. The critical plating procedures were achieved by private industry. The FPA mass is nearly 600 kg and installed in a beam structural support stand. In this paper, we summarize the FPA design basis and fabrication, plating, and assembly process steps with necessary lifting and handling fixtures. In addition, to ensure the quality of the FPA support structure a finite element analysis with seismic design forces has also been carried out.

  12. The mechanical design and fabrication of 162.5 MHz buncher for China accelerator driven sub-critical system injector II

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Hai Hua; Li, Youtang [Lanzhou University of Technology, Lanzhou (China); He, Yuan; Zhang, Bin; Huang, Shichun; Yuan, Chenzhang; Jia, Huan; Zhang, Shenghu [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China)

    2017-08-15

    A buncher is one of the main pieces of equipment in the medium energy beam transport line (MEBT) for China accelerator driven sub-critical system (C-ADS) Injector II. To focus the beam longitudinally and match the beam for the acceptance of the superconducting linac section, two room temperature quarter wave resonator (QWR) bunchers with frequency of 162.5 MHz have been designed as parts of the MEBT. According to the beam transmission matching of the MEBT and the geometric parameters requirements of bunchers, the unique mechanical structure and the main processing technology of buncher cavities and their couplers and tuners are described in this paper. The fabrication of bunchers and their parts have been completed and tested at high power, the test results agree well with the design requirements. These bunchers work well for about two years in Institute of Modern Physics, Chinese Academy of Sciences.

  13. The mechanical design and fabrication of 162.5 MHz buncher for China accelerator driven sub-critical system injector II

    Directory of Open Access Journals (Sweden)

    Haihua Niu

    2017-08-01

    Full Text Available A buncher is one of the main pieces of equipment in the medium energy beam transport line (MEBT for China accelerator driven sub-critical system (C-ADS Injector II. To focus the beam longitudinally and match the beam for the acceptance of the superconducting linac section, two room temperature quarter wave resonator (QWR bunchers with frequency of 162.5 MHz have been designed as parts of the MEBT. According to the beam transmission matching of the MEBT and the geometric parameters requirements of bunchers, the unique mechanical structure and the main processing technology of buncher cavities and their couplers and tuners are described in this paper. The fabrication of bunchers and their parts have been completed and tested at high power, the test results agree well with the design requirements. These bunchers work well for about two years in Institute of Modern Physics, Chinese Academy of Sciences.

  14. Design Anthropology in Participatory Design

    DEFF Research Database (Denmark)

    Smith, Rachel Charlotte; Kjærsgaard, Mette Gislev

    2015-01-01

    This focus section explores the opportunities of design anthropology in participatory design as an approach to research and design in an increasingly global and digital world. Traditionally, ethnography has been used in Participatory design to research real-life contexts and challenges, and as ways...... opportunities of using design anthropology as a holistic and critical approach to addressing societal challenges and change, and a way for anthropologists and designers to engage in participatory research and design that extend beyond the empirical....

  15. Design Considerations for the LHC 200 MHz RF System

    CERN Document Server

    Boussard, Daniel; Kindermann, H P; Linnecar, Trevor Paul R; Marque, S; Tückmantel, Joachim

    2000-01-01

    The longitudinal beam transfer from the SPS into the LHC 400 MHz buckets will not be free of losses without a lower frequency capture system and a fast longitudinal damping system in LHC. We present a complete study of a combined system using four identical copper cavities at 200 MHz delivering 3 MV total CW voltage and having still enough bandwidth to achieve fast longitudinal damping. The shape of a cavity was designed according to the accelerating mode performance, its tuning and the higher order mode spectrum with respect to the LHC beam lines and their possible attenuation. The possibility to park the cavities during coast was included. The local heat load and the corresponding cooling water distribution as well as deformations were studied and techniques to build the cavity with all ports at low cost are proposed. The parameters of the RF generators, couplers and detuning are determined. Simulations of the total LHC RF system incorporating real delays, generator bandwidth and the control loops confirm t...

  16. Design of PID temperature control system based on STM32

    Science.gov (United States)

    Zhang, Jianxin; Li, Hailin; Ma, Kai; Xue, Liang; Han, Bianhua; Dong, Yuemeng; Tan, Yue; Gu, Chengru

    2018-03-01

    A rapid and high-accuracy temperature control system was designed using proportional-integral-derivative (PID) control algorithm with STM32 as micro-controller unit (MCU). The temperature control system can be applied in the fields which have high requirements on the response speed and accuracy of temperature control. The temperature acquisition circuit in system adopted Pt1000 resistance thermometer as temperature sensor. Through this acquisition circuit, the monitoring actual temperature signal could be converted into voltage signal and transmitted into MCU. A TLP521-1 photoelectric coupler was matched with BD237 power transistor to drive the thermoelectric cooler (TEC) in FTA951 module. The effective electric power of TEC was controlled by the pulse width modulation (PWM) signals which generated by MCU. The PWM signal parameters could be adjusted timely by PID algorithm according to the difference between monitoring actual temperature and set temperature. The upper computer was used to input the set temperature and monitor the system running state via serial port. The application experiment results show that the temperature control system is featured by simple structure, rapid response speed, good stability and high temperature control accuracy with the error less than ±0.5°C.

  17. Engineering design and fabrication of X-Band components

    CERN Document Server

    Filippova, M; Solodko, A; Riddone, G; Syratchev, I

    2011-01-01

    The CLIC RF frequency has been changed in 2008 from the initial 30 GHz to the European X-band 11.994 GHz permitting beam independent power production using klystrons for the accelerating structure testing. X-band klystron test facilities at 11.424 GHz are operated at SLAC and at KEK [1], and they are used by the CLIC study in the framework of the X-band structure collaboration for testing accelerating structures scaled to that frequency [2]. CERN is currently building a klystron test-stand operating at 11.994 GHz. In addition X-FEL projects at PSI and Sincrotrone Trieste operate at 11.4 GHz. Therefore several RF components accommodating frequencies from 11.424 to 11.994 GHz are required. The engineering design of these RF components (high power and compact loads, bi-directional couplers, X-band splitters, hybrids, phase shifters, variable power attenuators) and the main fabrication processes are presented here.

  18. Microstrip Butler matrix design and realization for 7 T MRI.

    Science.gov (United States)

    Yazdanbakhsh, Pedram; Solbach, Klaus

    2011-07-01

    This article presents the design and realization of 8 × 8 and 16 × 16 Butler matrices for 7 T MRI systems. With the focus on low insertion loss and high amplitude/phase accuracy, the microstrip line integration technology (microwave-integrated circuit) was chosen for the realization. Laminate material of high permittivity (ε(r) = 11) and large thickness (h = 3.2 mm) is shown to allow the best trade-off of circuit board size versus insertion loss, saving circuit area by extensive folding of branch-line coupler topology and meandering phase shifter and connecting strip lines and reducing mutual coupling of neighboring strip lines by shield structures between strip lines. With this approach, 8 × 8 Butler matrices were produced in single boards of 310 mm × 530 mm, whereas the 16 × 16 Butler matrices combined two submatrices of 8 × 8 with two smaller boards. Insertion loss was found at 0.73 and 1.1 dB for an 8 × 8 matrix and 16 × 16 matrix, respectively. Measured amplitude and phase errors are shown to represent highly pure mode excitation with unwanted modes suppressed by 40 and 35 dB, respectively. Both types of matrices were implemented with a 7 T MRI system and 8- and 16-element coil arrays for RF mode shimming experiments and operated successfully with 8 kW of RF power. Copyright © 2011 Wiley-Liss, Inc.

  19. SRF technology at accel for worldwide accelerator projects

    International Nuclear Information System (INIS)

    Bauer, S.; Griep, B.; Peiniger, M.; Pekeler, M.; Piel, C.; Stein, P. vom; Vogel, H.

    2003-01-01

    Within the last two years activities at ACCEL for international accelerator projects using superconducting cavities have steadily increased. We report on our production work for CERN (HOM couplers for LHC cavities), DESY (TESLA cavities and couplers), Forschungszentrum Juelich (turn key low beta SRF module), SRRC, CLS and Cornell (turn key 500 MHz SRF modules. The production a superconducting Landau accelerator module for BESSY has started recently. In addition studies are under way for a superconducting 40 MeV proton/deuteron linac and for superconducting low beta multi gap structures. (author)

  20. Design Anthropology in Participatory Design

    DEFF Research Database (Denmark)

    Smith, Rachel Charlotte; Gislev Kjærsgaard, Mette

    2014-01-01

    In this workshop we explore the opportunities of ethnography and design anthropology in Participatory Design (PD) as an approach to design in an increasingly global and digital world. Traditionally, ethnography has been used in PD to research real-life contexts and challenges, and as ways...... opportunities of using design anthropology as a holistic and critical approach to societal challenges, and a way for anthropologists and designers to engage in design that extends beyond the empirical....