A   B   C   D   E   F   G   H   I   K   L   M   O   P   Q   R   S   T   U   V   W   X    

plasma

  
Paper Title Other Keywords Page
MOYAPA01 Laser-plasma Wakefield Acceleration: Concepts, Tests and Premises laser, electron, acceleration, target 10
 
  • V. Malka
    Ecole Polytechnique, Palaiseau
  • J. Faure
    CEA, Gif-sur-Yvette
  • Y. Glinec, A. Lifschitz
    LOA, Palaiseau
  The presentation will review all novel methods presently developed to reach high accelerating fields from the concepts, to simulations, feasibility demonstration in real tests and performances presently achieved. It will point out and compare their potential but also their technical challenges and possible limitations. It will also present the necessary R&D and the tests presently envisaged including schedule and milestones not only in terms of fields but also of beam quality preservation and power efficiency. Finally, possible future applications will be suggested.  
slides icon Transparencies
 
MOPCH109 Design Studies on a Novel Stellarator Type High Current Ion Storage Ring ion, injection, kicker, space-charge 297
 
  • M. Droba, N.S. Joshi, O. Meusel, P. Nonn, U. Ratzinger
    IAP, Frankfurt-am-Main
  A high current storage ring for the accumulation of ion beams provided by a new 150 kV terminal is under consideration at the Frankfurt University. The configuration based on a toroidal magnetic field seems promising for the storage of intense low energy ion beams, especially when concerning the various potential concepts for space charge compensation. The theory of plasma confinement on magnetic surface is transformed to numerical simulations on circulating ion beams. The space charge effects and stability conditions are studied and will be presented. Various injection techniques based on crossed field-drifts are investigated. Accordingly test experiments are prepared based on two 30 degree toroidal sectors at a major radius of 1.3m with a maximum toroidal magnetic field of 0.6T on axis.  
 
MOPCH168 Novel Development on Superconducting Niobium Film Deposition for RF Applications cathode, vacuum, ion, laser 457
 
  • A. Cianchi, L. Catani, D. D. Di Giovenale, J. Lorkiewicz
    INFN-Roma II, Roma
  • J. Langner, M. S. Sadowski, P. Strzyzewski
    The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock
  • V. M. Merlo, M. Salvato, S. Tazzari
    Università di Roma II Tor Vergata, Roma
  • B.R. Ruggiero, R. Russo
    ICIB, Pozzuoli (NA)
  A new deposition technology has been developed, based on a cathodic arc system working under UHV conditions, to produce metallic thin films. The technique presents several advantages compared to standard sputtering, mainly: ionized state of the evaporated material, absence of gases to sustain the discharge, higher energy of atoms reaching the substrate surface, possibility to apply bias to the substrate and to guide the arc plasma using magnetic fields. Recent results on superconducting Niobium films deposited under several conditions and on sapphire substrate are reported. A cavity deposition system has been developed and the plasma transport to the cavity cell studied  
 
MOPCH184 Plasma Treatment of Bulk Niobium Surfaces for SRF Cavities cathode, electron, ion, controls 493
 
  • L. Vuskovic, S. Popovic, M. Raskovic
    ODU, Norfolk, Virginia
  • L. Godet, S.B. Radovanov
    VSEA, Gloucester, Maryland
  • H.L. Phillips, A-M. Valente-Feliciano
    Jefferson Lab, Newport News, Virginia
  Cavity surface preparation has been one of the major problems in superconducting radio-frequency (SRF) accelerator technology. Accelerator performance depends directly on the physical and chemical characteristics at the SRF cavity surface. The primary objective of our work is to explore the effects of various types of electric discharge plasmas to minimize surface roughness and eliminate or minimize deterioration of cavity properties by oxygen, hydrogen and other chemical contaminants. To optimize the plasma etching process, samples of bulk Nb are being exposed to three types of electrical discharge in various experimental set-ups. The surface quality obtained by the three methods was compared with samples treated with buffer chemical polishing techniques. Surface comparisons are made using digital imaging (optical) microscopy, scanning electron microscopy, and atomic force microscopy. In preliminary tests, samples compared with those treated conventionally have shown comparable or superior properties. Tests have also shown that surface quality varies with plasma conditions and their optimization to obtain the best SRF cavity surface is a major goal of the ongoing work.  
 
TUPCH155 2D and 1D Surface Photonic Band Gap Structures for Accelerator Applications radiation, electron, SLAC, undulator 1388
 
  • I.V. Konoplev, A.W. Cross, W. He, P. MacInnes, A. Phelps, C.W. Robertson, K. Ronald, C.G. Whyte
    USTRAT/SUPA, Glasgow
  High frequency (26.5GHz to 40GHz), high power (tens of MW) microwave sources are required for cavity testing and conditioning applications in accelerators such as CLIC. The first study of microwave radiation from a co-axial Free-Electron Maser (FEM) based on a two-mirror cavity formed by a 2D Surface Photonic Band Gap (SPBG) structure (input mirror 10.4cm) and 1D SPBG structure (output mirror 10cm) is presented. The electron beam source consisted of a magnetically insulated plasma flare emission carbon cathode. Application of a 450kV voltage pulse of duration ~250ns across the cathode and grounded anode resulted in the production of a 7.0cm diameter annular electron beam of current ~1500A. The output radiation power from the FEM was measured using a Ka-band horn with 60dB of attenuation in front of a microwave detector located at a distance of 1.5m from the output window. By integrating the microwave power measured at the detector over the radiation pattern a total power of 50 (±10) MW corresponding to an efficiency of ~9% was calculated. The location of the operating frequency was found to lie between 35GHz and 39GHz, which agrees with theoretically predicted frequency of 37.2GHz.  
 
TUPLS093 AG Acceleration using DPIS ion, laser, target, rfq 1720
 
  • T. Kanesue, K. Ishibashi
    Kyushu University, Hakozaki
  • A. Kondrashev
    ITEP, Moscow
  • M. Okamura
    RIKEN, Saitama
  • K. Sakakibara
    RLNR, Tokyo
  We are investigating high current and high repetition rate ion production methods for various heavy ions which can be utilized for an injector of an FFAG accelerator. Direct Plasma Injection Scheme (DPIS) is one of the candidates of the ion production methods and to confirm the capability of the DPIS, we are now preparing for accelerating high intensity Ag15+ ions. The DPIS uses a combination of Laser Ion Source (LIS) and RFQ linac. The plasma goes into the linac directly without transportation line and the ions are extracted at RFQ entrance. To determine the specifications of new RFQ electrodes, the plasma properties were measured. With the Nd-glass laser (3 J / 30 ns), we could not obtain high charge state ions. A new Nd-YAG laser (2.3 J / 6 ns) enabled us to observe many high charged ions and the most produced ions were Ag15+. We completed the plasma distribution measurements. Based on these results, we designed the new RFQ, which will accommodate Q / M = 1 / 8 particles, supposing Ag+15.  
 
TUPLS096 Strongly Focused He+ Beam Source for Alpha Particle Measurement at ITER ion, extraction, diagnostics, ion-source 1726
 
  • K. Shinto, S. Kitajima, A. O. Okamoto, M. Sasao
    Tohoku University, Sendai
  • Y. H. Hirano, S. Kiyama, H. S. Sakakita
    AIST, Tsukuba, Ibaraki
  • O. Kaneko, M. Nishiura
    NIFS, Gifu
  • M. Wada
    Doshisha University, Graduate School of Engineering, Kyoto
  A He+ beam source for He0 beam probe for measurement of fusion produced alphas due to D-T nuclear reaction in a thermonuclear fusion plasma has been designed and constructed. The ion source consists of a 300 mm diameter and 280 mm length plasma chamber and a beam extraction system which has three concaved electrodes. Helium plasma is confined by line cusp magnetic fields produced by Sm-Co permanent magnets. The magnetic field strength near the extraction region is designed to be less than 20 gauss. Through the 100 mm diameter extraction area of the concaved electrodes 300 beamlets are formed with apertures of 4 mm. The focal length of the concaved electrodes is designed to be 750 mm. The beam quality of the extracted He+ beam will be measured by several beam diagnostic apparatuses. The total beam current, the beam profile and the beam emittance will be measured to design a proper alkali metal vapor cell for a He- beam production by a double charge exchange process and a beam transport line to the post accelerator up to MeV region. In the article, the details of the ion source and the beam diagnostic system will be described.  
 
TUPLS097 Application of DPIS to IH Linac linac, laser, target, ion 1729
 
  • J. Tamura, J. Hasegawa, T. Hattori, N. Hayashizaki, T. Ishibashi, T. Ito
    Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo
  • A. Kondrashev
    ITEP, Moscow
  • M. Okamura
    RIKEN, Saitama
  We are now designing a Laser Ion Source (LIS), which will be operated with an Inter-digital H (IH) structure linac using the Direct Plasma Injection Scheme (DPIS). The DPIS has been applied to RFQ linacs and has successfully achieved very high current with simple structure. The IH structure linac was designed to accept 40 keV proton beam which could be produced by the DPIS. The combination of the DPIS and IH structure linac will realize quite compact accelerator complex with intense proton beam. The detailed design study of a plasma production chamber with a cryogenic cooler is investigated.  
 
TUPLS099 The New 14 GHz Ion Source for the U-400 Heavy Ion Cyclotron ion, ion-source, cyclotron, resonance 1732
 
  • M. Leporis, V.B. Bekhterev, S.L. Bogomolov, A. Efremov, G. Gulbekyan, Yu.K. Kostyukhov, N. Lebedev, V.N. Loginov, Yu. Yazvitsky
    JINR, Dubna, Moscow Region
  The new 14 GHz ion source DECRIS-4, to be used as a second injector of heavy multiply charged ions for the U-400 cyclotron and, in the future, also as a "charge breeder" (the "1+ -> n+" method) for the second phase of the DRIBs project, has been designed and constructed at the FLNR. The main feature of the ion source design is the creation of the extended resonance zone in a comparatively compact ECRIS. For this purpose the axial magnetic field is formed with a flat minimum by mounting only one additional solenoid coil to the classical CAPRICE magnetic structure. In this case the superposition of the axial magnetic field and the radial field of the permanent magnet hexapole, made from NdFeB, allows one to create a larger resonance volume. First results of the ion source tests show that in this resonance volume electrons are heated very efficiently which allows to produce intense beams of medium charge state ions with comparatively low level of input microwave power. The basic design features, construction issues and the first results of ion source tests are presented.  
 
TUPLS100 Generation of Highly Charged Ions Using ND-glass Laser ion, laser, target, vacuum 1735
 
  • A. Kondrashev
    ITEP, Moscow
  • T. Kanesue
    Kyushu University, Fukuoka
  • M. Okamura
    RIKEN, Saitama
  • K. Sakakibara
    RLNR, Tokyo
  The parameters of ions (charge state distributions, currents and pulse durations) were measured in laser plasma generated by 3 J/30 ns Nd-glass laser for wide range of elements from 12C to 181Ta and for different laser power densities at the target surface. It is shown that such a laser can effectively generate highly charged ions for elements from 12C to 56Fe. Registered ion charge states significantly drops for heavier elements because of recombination losses of highly charged ions during laser produced plasma expansion into vacuum. Absolute currents and numbers of ions with different charge states were obtained by normalization of charge state distributions summary on total ion currents measured by Faraday cup for 1011 W/cm2 and 1012 W/cm2 laser power densities at the target surface. The results obtained are very useful for Laser Ion Source (LIS) development, in particular, for Direct Plasma Injection Scheme (DPIS) study*.

*M. Okamura et al. Laser and Particle Beams, 20, 2002, pp. 451 - 454.

 
 
TUPLS103 Further Development of a Low Inductance Metal Vapor Vacuum Arc (LIZ-MeVVA) Ion Source ion, extraction, vacuum, electron 1738
 
  • B.M. Johnson
    APS, Ridge
  • E. Garate, R. McWilliams, J.P. Sprunck, A. van Drie
    University of California IIrvine, Irvine, California
  • A. Hershcovitch
    BNL, Upton, Long Island, New York
  A Low Impedance Z-Discharge Metal Vapor Vacuum Arc (LIZ-MeV) ion source* is being explored as an alternate pre-injector for the Brookhaven Relativistic Heavy Ion Collider (RHIC). With the vacuum arc operating at tens of kiloamperes and an aluminum electrode, LIZ-MeV has been run in two regimes: an LC dominated "ringing" arc of period 4.1 microseconds, which decays after about 6 cycles, and a 1-3 microsecond wide "pulsed" arc, where a small series resistance has been added to critically damp ringing. Metal ions are extracted from the plasma using a two-grid system with a triggered, variable-delay voltage of up to 10 kV. Time-of-Flight (TOF) measurements are taken using a Faraday cup located at the end of a 15-76 cm drift tube. TOF measurements from both arc regimes have been obtained suggesting generation of about a billion ions per pulse of charge states +1 and +2, and occasionally +3 states. TOF results are compared with simple theoretical models.

*B. M. Johnson, et al. Two approaches to electron beam enhancement of the metal vapor vacuum arc ion source. Laser and Particle Beams 21, 103 (2003).

 
 
TUPLS105 Sputter Probes and Vapor Sources for ECR Ion Sources ion, cathode, electron, ion-source 1744
 
  • M. Cavenago, A. Galatà, M. Sattin
    INFN/LNL, Legnaro, Padova
  • T. Kulevoy, S. Petrenko
    ITEP, Moscow
  Sputter probes are a promising method for injecting controlled quantities of metallic elements inside ECRIS ion source, provided that sputter rate can be controlled, so that high charge states and low sample consumption rate will be attained. Moreover pressure at the probe and inside source should be different. With a simple differential pumping scheme and a sputter probe at 25 mm from ECRIS plasma, a 200 nA current of 120Sn18+ was easily obtained. Typical results (for Sn and Ti) of an inductively heated rf oven are discussed for comparison. Improvements of sputter probe concept and geometry are also described.  
 
WEPCH101 Ion Motion in the Adiabatic Focuser ion, electron, emittance, focusing 2149
 
  • A. Sessler, E. Henestroza, S. Yu
    LBNL, Berkeley, California
  The Adiabatic Focuser* works by having a focusing channel whose strength increases with distance down the channel. In this situation electrons of various energies and various transverse oscillation phase all are transversely focused. The concept works with external focusing, but would be very effective in a plasma ion focusing channel where the density of ions is simply increased as one goes down the channel. In the original work (Ref 1) motion of the ions was not included (as it was assumed to be a small effect). Recently, it has been suggested that ion motion in an adiabatic focuser would be significant and, even, preclude operation of the focuser as previously envisioned**. In this paper we numerically study the ion motion in the focuser. The ions clearly influence each other and, most importantly, are influenced by the electric field of the electrons being focused. It is shown that parameters can be selected such that the adiabatic focuser works as well as originally envisioned.

*P. Chen et al. Phys. Rev. Lett. 64, 1231 (1990).**J. R. Rosenzweig, et al. Phys. Rev. Lett. 95, 195002 (2005).

 
 
WEPCH126 Issues in Modelling of Negative Ion Extraction ion, extraction, electron, scattering 2218
 
  • M. Cavenago
    INFN/LNL, Legnaro, Padova
  • V. Antoni, F. Sattin
    CNR/RFX, Padova
  In the context of negative ion sources proposed for neutral beam injectors for tokamaks, halo of the extracted beam is typically large (about 10 %) and optimum shape of the multiaperture extraction electrode is a matter of research. Present designs range from an aperture angle of 45 degree (low current, convergent beam) to 90 degrees (flat electrode, high current, large divergence and halo). Two major difficulties of the beam extraction modelling are here discussed. First, the generation processes of negative ion show some shortcomings: volume production seems low; wall production is large, but ions have wrong directions and/or large nonuniformity in current density; elastic scattering of wall generated ions into the extraction direction must compete with mutual neutralization. Second, the plasma sheath charge has to be negative on the extraction hole surface and positive on the nearby wall surface, which enhances beam aberration near hole edge. After discussing limitation of existing codes and model, result from an ad hoc code are discussed. Also 2D equation for the selfconsistent electrostatic field can be written and implemented into a multiphysics general purpose program.  
 
WEPCH147 Simulations of Electron Effects in Superconducting Cavities with the VORPAL Code electron, simulation, laser, radio-frequency 2269
 
  • C. Nieter, J.R. Cary, P. Messmer, D.S. Smithe, P. Stoltz
    Tech-X, Boulder, Colorado
  • G.R. Werner
    CIPS, Boulder, Colorado
  Modeling the complex boundaries of superconducting radio frequency (SRF) accelerating cavities on a Cartesian grid is a challenge for many Finite Difference Time Domain (FDTD) electromagnetic PIC codes. The simulation of such cavities require conformal (curve fitting) boundaries. Modeling the full cavity including couplers and ports is fundamentally a three dimensional problem requiring capability to run in parallel on large numbers of processors. We have recently added conformal boundaries using the method of Zagorodnov* to the plasma simulation code VORPAL. Using this higher order boundary algorithm and the surface physics package TxPhysics, we have begun studies of self-consistent electron effects in SRF cavities. We have modeled the beam excitation of cavity modes and the effects of electron multipacting. Results from these studies will be presented using the new user friendly visualization tool that now ships with VORPAL.

*I. A. Zagorodnov et al. “A uniformly stable conformal FDTD-method in Cartesian grids,” International Journal of Numerical Modeling 16, 127 (2003).

 
 
WEPCH181 Ion Implantation Via Laser Ion Source ion, laser, target, extraction 2355
 
  • F. Belloni, D. Doria, A. Lorusso, V. Nassisi
    INFN-Lecce, Lecce
  We report on the development of a new implantation technique via laser ion source. By applying a high voltage on the accelerating gap, this compact device was able to accelerate towards a substrate ions from ablation plasma. The occurrence of arcs during the extraction phase was a major problem to overcome. A pulsed KrF laser was utilized to produce plasma by ablation of solid targets. Radiation wavelength and pulse duration were 248 nm and 20 ns, respectively. The laser beam, 70 mJ per pulse, was focused onto different targets in a spot of about 1 mm2 in surface, obtaining an irradiance value of about 3.5 x 108 W/cm2. The implanted samples were characterized by energy dispersive x-ray spectroscopy, Rutherford backscattering spectrometry and x-ray photoelectron spectrometry. Implantations of Al, Cu and Ge on Si substrates were carried out up to 80 nm in depth, operating at 40 kV acceleration voltage. Ion dose was estimated by Faraday cup diagnostics. It was of the order of 1010 ions/cm2 per pulse.  
 
WEPLS028 Improvement of Electron Generation from a Laser Plasma Cathode through Modified Preplasma Conditions Using an Artificial Prepulse laser, electron, cathode, acceleration 2448
 
  • K. Kinoshita, T. Hosokai, K. Kobayashi, A. Maekawa, T. Ohkubo, T. Tsujii, M. Uesaka
    UTNL, Ibaraki
  • A. Yamazaki
    KURRI, Osaka
  • A.G. Zhidkov
    NIRS, Chiba-shi
  We have been studying the effects of laser prepulses, plasma cavity formation, wave breaking processes in the laser plasma acceleration. It is important to control the preplasma conditions, so as to stabilize the laser plasma acceleration. The modification of the conditions of the laser plasma interaction through an artificial prepulse, magnetic fields, and/or gas density modulation will affect on the characteristics of accelerated electron beams. As the first step, we carry out experiments with an artificial prepulse. If a shockwave driven by the artificial prepulse matches the main pulse foccal position, localized wave breaking may occur effectively, and consequent electron generation will be enhanced. We use a pulse with 10% energy of the main pulse and 300 ps duration to be focused on the interaction point of the gas jet, to change the plasma distribution there. Using the single-shot diagnosis, we investigate the mechanism and technique to improve the properties of electron beams. We observed a strong correlation between the generation of monoenergetic electrons and optical guiding of the main pulse, during the interaction of 11 TW 37 fs laser pulse and He gas jet.  
 
WEPLS029 Monoenergetic 200fs (FWHM) Electron Bunch Measurement from the Laser Plasma Cathode electron, radiation, laser, cathode 2451
 
  • A. Maekawa, T. Hosokai, K. Kinoshita, K. Kobayashi, T. Ohkubo, T. Tsujii, M. Uesaka
    UTNL, Ibaraki
  • Y. Kondo, Y. Shibata
    Tohoku University, Sendai
  • T. Takahashi, A. Yamazaki
    KURRI, Osaka
  • A.G. Zhidkov
    NIRS, Chiba-shi
  A laser plasma accelerator is the most promising approach to compact accelerators that can generate femtosecond electron bunches. It is expected that the electron bunch duration less than 100fs can be achieved owing to the high frequency of plasma waves. Since the time-resolution of the fastest streak camera is only 200fs, we have to use the coherent transition radiation (CTR) measurement or E/O (electro-optical) method. We plan to perform a single-shot measurement by getting the whole CTR spectrum by a IR polychromator in near future. As the first step forward it, we used a IR bolometer with different filters and obtained the average spectrum. We can generate monoenergetic electron bunches in the condition of laser intensity 3x1019W/cm2 and electron density 6x1019cm-3. The charge is estimated to be about 10pC using ICT (Integrated Current Transformer). The electron bunch accelerated by plasma waves penetrates 300um Ti-foil, and transition radiation is emitted. We measure CTR spectrum using a bolometer. Spectrum distribution of CTR depends on the electron bunch distribution, therefore we can evaluate the bunch duration from it. In the experiment, bunch duration can be estimated.  
 
WEPLS050 Experiments with Electron Cloud and Sources electron, ion, laser, injection 2490
 
  • M. Cavenago
    INFN/LNL, Legnaro, Padova
  • G. Bettega, F. Cavaliere, D. Ghezzi, A. Illiberi, R. Pozzoli, M. Rome
    INFN-Milano, Milano
  The Penning-Malmberg trap ELTRAP installed at University of Milano can provide electron clouds of several sizes for study of non-linear physics: length ranges from 0.15 to 1 m, while diameter is varied between 25 mm and 70 mm by changing the electron source: filament or planar spiral. Vortices develop both in trapped and flowing electron beams. Slow instabilities, due to the accumulation of ions inside the trap are observed and cured by clearing fields. Results as a function of plasma size are described. Plan to install a third laser modulated electron source and additional diagnostic are also summarized.  
 
THPCH023 Vlasov Equilibrium of a Periodically Twisted Ellipse-shaped Charged-particle Beam in a Non-axisymmetric Periodic Magnetic Focusing Field focusing, emittance, klystron, permanent-magnet 2826
 
  • J.Z. Zhou, C. Chen
    MIT/PSFC, Cambridge, Massachusetts
  A new Vlasov equilibrium is obtained for a periodically twisted ellipse-shaped charged-particle beam in a non-axisymmetric periodic permanent magnetic focusing field. The equilibrium distribution function is derived, and the statistical properties of the beam equilibrium are studied. The generalized envelope equations derived from the kinetic theory recovers the generalized envelope equations obtained in the cold-fluid theory when the temperature is taken to be zero*. Examples of periodically twisted elliptic beam equilibrium are presented and applications are explored.

*J. Zhou et al. “Exact Paraxial Cold-Fluid Equilibrium of a High-Intensity Periodically Twisted Ellipse-Shaped Charged-Particle Beam,” Phys. Rev. ST Accel. Beams, submitted for publication (2005).

 
 
THPCH139 Development of an Ion Source via Laser Ablation Plasma ion, extraction, target, laser 3119
 
  • F. Belloni, D. Doria, A. Lorusso, V. Nassisi
    INFN-Lecce, Lecce
  • L. Torrisi
    INFN/LNS, Catania
  Experimental results on the development of a laser ion source (LIS) are reported. LISs are particularly useful in ion accelerators, ion implanters and devices for electromagnetic isotope separation. A focused UV laser beam (0.1 - 1 GW/cm2 power density) was used to produce a plasma plume from a Cu target. Several aspects were investigated: ion angular distribution, energy distribution, ion extraction and charge loss due to ion recombination. Particular attention was devoted to avoid arcs during the extraction phase; it was accomplished by allowing the proper plasma expansion in a suitable chamber before the extraction gap. Diagnostics on free expanding plasma and extracted ions was carried out mainly by time-of-flight measurements, performed by means of Faraday cups and electrostatic spectrometers. At 18kV acceleration voltage, the ion beam current, measured along a drift tube at 147cm from the target, resulted modulated on ion mass-to-charge ratio and its maximum value was 220uA. The Cu+1 ion bunch charge was estimated to be 4.2nC. Ion implantation tests were successfully performed at high acceleration voltage (several tens kV), by using a simple experimental arrangement.  
 
THPCH149 Active RF Pulse Compression using Electrically Controlled Semiconductor Switches simulation, coupling, SLAC, laser 3140
 
  • J. Guo, S.G. Tantawi
    SLAC, Menlo Park, California
  In this paper, we present the recent results of our research on the ultra-high power fast silicon RF switch and its application on active X-Band RF pulse compression systems. This switch is composed of a group of PIN diodes on a high purity silicon wafer. The wafer is inserted into a cylindrical waveguide operating in the T·1001 mode. Switching is performed by injecting carriers into the bulk silicon through a high current pulse. Our current design uses a CMOS compatible process and the fabrication is accomplished at SNF (Stanford Nanofabrication Facility). The RF energy is stored in a room-temperature, high-Q 400 ns delay line; it is then extracted out of the line in a short time using the switch. The pulse compression system has achieved a gain of 11, which is the ratio between output and input power. Power handling capability of the switch is estimated at the level of 10MW.  
 
THPCH176 Deposition of Lead Thin Films Used as Photo-cathodes by Means of Cathodic Arc under UHV Conditions vacuum, cathode, gun, ion 3209
 
  • P. Strzyzewski, J. Langner, M. S. Sadowski, J. Witkowski
    The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock
  • T. Rao, J. Smedley
    BNL, Upton, Long Island, New York
  • R. Russo, S. Tazzari
    Università di Roma II Tor Vergata, Roma
  • J.S. Sekutowicz
    DESY, Hamburg
  The cathodic arc technology has been used for various technical purposes for many years. Recently, it has been demonstrated that the cathodic arc can be operated under ultra-high vacuum (UHV) conditions and it might solve the problem of the oxygen contamination coming from water remnants. It opens a new road to many applications where very pure metallic and/or superconducting films are needed. The paper reports on recent experimental studies aimed on the deposition of superconducting films of pure lead (Pb) by means of the UHV cathodic arc. Such layers can be used as photo-cathodes needed for modern accelerator injectors. The system configuration, used for thin film deposition inside the RF Gun designed at DESY, is also described and the main results and characteristics of thin superconducting Pb-films are presented.  
 
THPCH195 New Developments on Low-loss Ferroelectrics for Accelerator Applications controls, collider, coupling, linear-collider 3251
 
  • A. Kanareykin, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio
  • A. Dedyk, S.F. Karmanenko
    Eltech University, St. Petersburg
  • E. Nenasheva
    Ceramics Ltd., St. Petersburg
  • V.P. Yakovlev
    Omega-P, Inc., New Haven, Connecticut
  Recent results on development of BST (barium strontium titanium oxide composition) ferroelectric materials are presented to be used as the basis for new advanced technology components suitable for high-gradient accelerators. Ferroelectric materials offer significant benefits for linear collider applications, in particular, for switching and control elements where a very short response time of 10 ns can be potentially achieved. The applications include: fast active X-band and Ka-band high-power ferroelectric switches, high-power X-band, and L-band ferroelectric-based phase-shifters. The recently developed large diameter (11 cm) BST-based ferroelectric rings will be used at high pulse power (tens of megawatts) for the X-band components as well as at high average power (in the range of a few kilowatts) for the L-band phase-shifters, which are suitable for ILC applications.  
 
THPLS001 The Strict Solution of a Radiation Problem in Toroidal Cavity radiation, synchrotron, synchrotron-radiation, electromagnetic-fields 3260
 
  • T.H. Harutunyan
    YSU, Yerevan
  • E.D. Gazazyan, M.K. Khojoyan
    YerPhI, Yerevan
  The radiation of charged particles bunch which is moving along the axes of toroidal cavity cross section is considered. The toroidal cavity has a finite value of the quality factor and is filled with special symmetry inhomogeneous dielectric medium. The problem's solution is based on the complete set of the toroidal cavity's own modes being defined strictly for the mentioned dielectric medium the cavity is filled with. The charged particles bunch exists in the cavity during a finite time period and the charged bunch's arising and vanishing effects are examined and are taken into account as well. The toroidal cavity is considered as a convenient model to investigate the electromagnetic properties of the tokamak system, using the defined modes.  
 
FRYCPA01 ITER and International Scientific Collaboration controls, vacuum, site, diagnostics 3641
 
  • S. Chiocchio
    MPI/IPP, Garching
  The presentation will describe the status and perspectives of the ITER Project. It will also explore the possible connection between the accelerator and the fusion worlds. The talk will cover experience in the managerial and sociological aspects of the worldwide collaboration of which ITER is the end result, very similar to the issues facing the accelerator community, which also faces projects of similar scope from the point of view of time span, technical complexity and sociological impact.  
slides icon Transparencies