WorldWideScience

Sample records for counter neutral beam

  1. Merged neutral beams

    Energy Technology Data Exchange (ETDEWEB)

    Osterwalder, Andreas [Ecole Polytechnique Federale de Lausanne (EPFL), Institute for Chemical Sciences and Engineering, Lausanne (Switzerland)

    2015-12-15

    A detailed description of a merged beam apparatus for the study of low energy molecular scattering is given. This review is intended to guide any scientist who plans to construct a similar experiment, and to provide some inspiration in describing the approach we chose to our goal. In our experiment a supersonic expansion of paramagnetic particles is merged with one of polar molecules. A magnetic and an electric multipole guide are used to bend the two beams onto the same axis. We here describe in detail how the apparatus is designed, characterised, and operated. (orig.)

  2. BEAMS3D Neutral Beam Injection Model

    Science.gov (United States)

    McMillan, Matthew; Lazerson, Samuel A.

    2014-09-01

    With the advent of applied 3D fields in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous slowing down, and pitch angle scattering are modeled with the ADAS atomic physics database. Elementary benchmark calculations are presented to verify the collisionless particle orbits, NBI model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields. Notice: this manuscript has been authored by Princeton University under Contract Number DE-AC02-09CH11466 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.

  3. ORNL positive ion neutral beam program

    Energy Technology Data Exchange (ETDEWEB)

    Whealton, J.H.; Haselton, H.H.; Barber, G.C.

    1978-01-01

    The neutral beam group at Oak Ridge National Laboratory has constructed neutral beam generators for the ORMAK and PLT devices, is presently constructing neutral beam devices for the ISX and PDX devices, and is contemplating the construction of neutral beam systems for the advanced TNS device. These neutral beam devices stem from the pioneering work on ion sources of G. G. Kelley and O. B. Morgan. We describe the ion sources under development at this Laboratory, the beam optics exhibited by these sources, as well as some theoretical considerations, and finally the remainder of the beamline design.

  4. Plasma/Neutral-Beam Etching Apparatus

    Science.gov (United States)

    Langer, William; Cohen, Samuel; Cuthbertson, John; Manos, Dennis; Motley, Robert

    1989-01-01

    Energies of neutral particles controllable. Apparatus developed to produce intense beams of reactant atoms for simulating low-Earth-orbit oxygen erosion, for studying beam-gas collisions, and for etching semiconductor substrates. Neutral beam formed by neutralization and reflection of accelerated plasma on metal plate. Plasma ejected from coaxial plasma gun toward neutralizing plate, where turned into beam of atoms or molecules and aimed at substrate to be etched.

  5. Plasma/Neutral-Beam Etching Apparatus

    Science.gov (United States)

    Langer, William; Cohen, Samuel; Cuthbertson, John; Manos, Dennis; Motley, Robert

    1989-01-01

    Energies of neutral particles controllable. Apparatus developed to produce intense beams of reactant atoms for simulating low-Earth-orbit oxygen erosion, for studying beam-gas collisions, and for etching semiconductor substrates. Neutral beam formed by neutralization and reflection of accelerated plasma on metal plate. Plasma ejected from coaxial plasma gun toward neutralizing plate, where turned into beam of atoms or molecules and aimed at substrate to be etched.

  6. Neutral Beams from Blazar Jets

    Science.gov (United States)

    Atoyan, Armen M.; Dermer, Charles D.

    2003-03-01

    We treat the production of neutrons, photons, and neutrinos through photomeson interactions of relativistic protons with ambient photons in the compact inner jets of blazars. Internal synchrotron and external isotropic radiation due to scattered optical/UV accretion-disk radiation are considered as target photon fields. Protons are assumed to be accelerated to a maximum energy limited by the size scale and magnetic field of the jet, and by competing energy losses. We characterize the conditions when the photomeson interactions of ultrarelativistic protons become effective, and show that the presence of the external radiation field makes possible strong energy losses for protons with energies Ep>~1015 eV. Without this component, effective energy losses of protons begin at Ep>~1018 eV, and would rapidly disappear with expansion of the blob. We develop a model describing the production and escape of neutrons from a comoving spherical blob, which continue to interact with the ambient external radiation field on the parsec-scale broad-line region (BLR). Neutrons may carry ~10% of the overall energy of the accelerated protons with Ep>~1015 eV outside the BLR. Ultra-high-energy gamma rays produced by photomeson interaction of neutrons outside the blob can also escape the BLR. The escaping neutrons, gamma rays, and neutrinos form a collimated neutral beam with a characteristic opening angle θ~1/Γ, where Γ is the bulk Lorentz factor of the inner jet. Energy and momentum is deposited in the extended jet from the decay of neutrons at distances ld(En)~(En/1017eV) kpc, and through pair-production attenuation of gamma rays with energies Eγ>~1015 eV which propagate to ~10-100 kpc distances. In this scenario, neutral beams of ultra-high-energy gamma rays and neutrons can be the reason for straight extended jets, such as in Pictor A. Fluxes of neutrinos detectable with kilometer-scale neutrino telescopes are predicted from flat-spectrum radio quasars such as 3C 279.

  7. Beyond ITER: Neutral beams for DEMO

    CERN Document Server

    McAdams, R

    2013-01-01

    In the development of magnetically confined fusion as an economically sustainable power source, ITER is currently under construction. Beyond ITER is the DEMO programme in which the physics and engineering aspects of a future fusion power plant will be demonstrated. DEMO will produce net electrical power. The DEMO programme will be outlined and the role of neutral beams for heating and current drive will be described. In particular, the importance of the efficiency of neutral beam systems in terms of injected neutral beam power compared to wallplug power will be discussed. Options for improving this efficiency including advanced neutralisers and energy recovery are discussed.

  8. INTOR neutral beam injector concept

    Energy Technology Data Exchange (ETDEWEB)

    Metzler, D.H.; Stewart, L.D.

    1981-01-01

    The US INTOR phase 1 effort in the plasma heating area is described. Positive ion based sources extrapolated from present day technology are proposed. These sources operate at 175 keV beam energy for 6 s. Five injectors - plus one spare - inject 75 MW. Beam energy, source size, interface, radiation hardening, and many other studies are summarized.

  9. Neutron production by neutral beam sources

    Energy Technology Data Exchange (ETDEWEB)

    Berkner, K.H.; Massoletti, D.J.; McCaslin, J.B.; Pyle, R.V.; Ruby, L.

    1979-11-01

    Neutron yields, from interactions of multiampere 40- to 120-keV deuterium beams with deuterium atoms implanted in copper targets, have been measured in order to provide input data for shielding of neutral-deuterium beam facilities for magnetic fusion experiments.

  10. Results on intense beam focusing and neutralization from the neutralized beam experiment

    Energy Technology Data Exchange (ETDEWEB)

    Roy, P.K.; Yu, S.S.; Eylon, S.; Henestroza, E.; Anders, A.; Bieniosek, F.M.; Greenway, W.G.; Logan, B.G.; Waldron, W.L.; Vanecek, D.L.; Welch, D.R.; Rose, D.V.; Davidson, R.C.; Efthimion, P.C.; Gilson, E.P.; Sefkow, A.B.; Sharp, W.M.

    2003-10-31

    We have demonstrated experimental techniques to provide active neutralization for space-charge dominated beams as well as to prevent uncontrolled ion beam neutralization by stray electrons. Neutralization is provided by a localized plasma injected from a cathode arc source. Unwanted secondary electrons produced at the wall by halo particle impact are suppressed using a radial mesh liner that is positively biased inside a beam drift tube. We present measurements of current transmission, beam spot size as a function of axial position, beam energy and plasma source conditions. Detailed comparisons with theory are also presented.

  11. Spatial calibration of a tokamak neutral beam diagnostic using in situ neutral beam emission

    Energy Technology Data Exchange (ETDEWEB)

    Chrystal, C. [Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831 (United States); Burrell, K. H.; Pace, D. C. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Grierson, B. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451 (United States)

    2015-10-15

    Neutral beam injection is used in tokamaks to heat, apply torque, drive non-inductive current, and diagnose plasmas. Neutral beam diagnostics need accurate spatial calibrations to benefit from the measurement localization provided by the neutral beam. A new technique has been developed that uses in situ measurements of neutral beam emission to determine the spatial location of the beam and the associated diagnostic views. This technique was developed to improve the charge exchange recombination (CER) diagnostic at the DIII-D tokamak and uses measurements of the Doppler shift and Stark splitting of neutral beam emission made by that diagnostic. These measurements contain information about the geometric relation between the diagnostic views and the neutral beams when they are injecting power. This information is combined with standard spatial calibration measurements to create an integrated spatial calibration that provides a more complete description of the neutral beam-CER system. The integrated spatial calibration results are very similar to the standard calibration results and derived quantities from CER measurements are unchanged within their measurement errors. The methods developed to perform the integrated spatial calibration could be useful for tokamaks with limited physical access.

  12. Modelling the neutralisation process in neutral beam injectors

    OpenAIRE

    Fitzgerald, Niall J.

    2009-01-01

    High power neutral beams currently play an important role in heating, fuelling and diagnosing magnetically confined thermonuclear fusion plasmas. At the Joint European Torus (JET) in Oxfordshire, England, the formation of such a beam involves passing a positive ion beam through a neutral gas target wherein beam electron-capture collisions result in a neutral beam component. The subsequent beam injection into the fusion plasma requires the sole use of this neutral component, since the charged ...

  13. Development of KSTAR Neutral Beam Heating System

    Energy Technology Data Exchange (ETDEWEB)

    Oh, B. H.; Song, W. S.; Yoon, B. J. (and others)

    2007-10-15

    The prototype components of a neutral beam injection (NBI) system have been developed for the KSTAR, and a capability of the manufactured components has been tested. High power ion source, acceleration power supply, other ion source power supplies, neutralizer, bending magnet for ion beam separation, calorimeter, and cryo-sorption pump have been developed by using the domestic technologies and tested for a neutral beam injection of 8 MW per beamline with a pulse duration of 300 seconds. The developed components have been continuously upgraded to achieve the design requirements. The development technology of high power and long pulse neutral beam injection system has been proved with the achievement of 5.2 MW output for a short pulse length and 1.6 MW output for a pulse length of 300 seconds. Using these development technologies, the domestic NB technology has been stabilized under the development of high power ion source, NB beamline components, high voltage and current power supplies, NB diagnostics, NB system operation and control.

  14. ITER neutral beam system US conceptual design

    Energy Technology Data Exchange (ETDEWEB)

    Purgalis, P.

    1990-09-01

    In this document we present the US conceptual design of a neutral beam system for International Thermonuclear Experimental Reactor (ITER). The design incorporates a barium surface conversion D{sup {minus}} source feeding a linear array of accelerator channels. The system uses a dc accelerator with electrostatic quadrupoles for strong focusing. A high voltage power supply that is integrated with the accelerator is presented as an attractive option. A gas neutralizer is used and residual ions exiting the neutralizer are deflected to water-cooled dumps. Cryopanels are located at the accelerator exit to pump excess gas from the source and the neutralizer, and in the ion dump cavity to pump re-neutralized ions and neutralizer gas. All the above components are packaged in compact identical, independent modules which can be removed for remote maintenance. The neutral beam system delivers 75 MW of DO at 1.3 MeV, into three ports with a total of 9 modules arranged in stacks of three modules per port . To increase reliability each module is designed to deliver up to 10 MW; this allows eight modules operating at partial capacity to deliver the required power in the event one module is out of service, and provides 20% excess capacity to improve availability. Radiation protection is provided by shielding and by locating critical components in the source and accelerator 46.5 m from the torus centerline. Neutron shielding in the drift duct and neutralizer provides the added feature of limiting conductance and thus reducing gas flow to and from the torus.

  15. PLASMA EMISSION BY COUNTER-STREAMING ELECTRON BEAMS

    Energy Technology Data Exchange (ETDEWEB)

    Ziebell, L. F.; Petruzzellis, L. T.; Gaelzer, R. [Instituto de Física, UFRGS, Porto Alegre, RS (Brazil); Yoon, P. H. [Institute for Physical Science and Technology, University of Maryland, College Park, MD (United States); Pavan, J., E-mail: luiz.ziebell@ufrgs.br, E-mail: yoonp@umd.edu, E-mail: joel.pavan@ufpel.edu.br [Instituto de Física e Matemática, UFPel, Pelotas, RS (Brazil)

    2016-02-10

    The radiation emission mechanism responsible for both type-II and type-III solar radio bursts is commonly accepted as plasma emission. Recently Ganse et al. suggested that type-II radio bursts may be enhanced when the electron foreshock geometry of a coronal mass ejection contains a double hump structure. They reasoned that the counter-streaming electron beams that exist between the double shocks may enhance the nonlinear coalescence interaction, thereby giving rise to more efficient generation of radiation. Ganse et al. employed a particle-in-cell simulation to study such a scenario. The present paper revisits the same problem with EM weak turbulence theory, and show that the fundamental (F) emission is not greatly affected by the presence of counter-streaming beams, but the harmonic (H) emission becomes somewhat more effective when the two beams are present. The present finding is thus complementary to the work by Ganse et al.

  16. Consideration of neutral beam prompt loss in the design of a tokamak helicon antenna

    Energy Technology Data Exchange (ETDEWEB)

    Pace, D.C., E-mail: pacedc@fusion.gat.com; Van Zeeland, M.A.; Fishler, B.; Murphy, C.

    2016-11-15

    Highlights: • Neutral beam prompt losses place appreciable power on an in-vessel tokamak antenna. • Simulations predict prompt loss power and inform protective tile design. • Experiments confirm the validity of the prompt loss simulations. - Abstract: Neutral beam prompt losses (injected neutrals that ionize such that their first poloidal transit intersects with the wall) can put appreciable power on the outer wall of tokamaks, and this power may damage the wall or other internal components. These prompt losses are simulated including a protruding helicon antenna installation in the DIII-D tokamak and it is determined that 160 kW of power will impact the antenna during the injection of a particular neutral beam. Protective graphite tiles are designed in response to this modeling and the wall shape of the installed antenna is precisely measured to improve the accuracy of these calculations. Initial experiments confirm that the antenna component temperature increases according to the amount of neutral beam energy injected into the plasma. In this case, only injection of beams that are aimed counter to the plasma current produce an appreciable power load on the outer wall, suggesting that the effect is of little concern for tokamaks featuring only co-current neutral beam injection. Incorporating neutral beam prompt loss considerations into the design of this in-vessel component serves to ensure that adequate protection or cooling is provided.

  17. Targets for a Neutral Kaon Beam

    Energy Technology Data Exchange (ETDEWEB)

    Keith, Christopher [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-04-01

    A secondary beam of neutral Kaons is under consideration for Hall D at Jefferson Lab to perform spectroscopic studies of hyperons produced by K 0 L particles scattering from proton and deuteron targets. The proposed physics program would utilize the GlueX detector package currently installed in Hall D. This contribution looks at potential targets for use in the new facility, paying close attention to the existing infrastructure of GlueX and Hall D. Unpolarized cryotargets of liquid hydrogen and deuerium, as well as polarized solid targets of protons and deuterons are examined.

  18. Nitridation of silicon by nitrogen neutral beam

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Yasuhiro, E-mail: yasuhirohara2002@yahoo.co.jp [Organization for Research and Development of Innovative Science and Technology, Kansai University, Yamate-cho 3-3-35, Suita 564-8680, Osaka (Japan); Shimizu, Tomohiro; Shingubara, Shoso [Department of Mechanical Engineering, Faculty of Engineering Science, Kansai University, Yamate-cho 3-3-35, Suita 564-8680, Osaka (Japan)

    2016-02-15

    Graphical abstract: - Highlights: • Nitrided silicon was formed by nitrogen neutral beam at room temperature. • Si{sub 3}N{sub 4} layer was formed at the acceleration voltage more than 20 V. • Formed Si{sub 3}N{sub 4} layer show the effective as the passivation film in the wet etching process. - Abstract: Silicon nitridation was investigated at room temperature using a nitrogen neutral beam (NB) extracted at acceleration voltages of less than 100 V. X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of a Si{sub 3}N{sub 4} layer on a Si (1 0 0) substrate when the acceleration voltage was higher than 20 V. The XPS depth profile indicated that nitrogen diffused to a depth of 36 nm for acceleration voltages of 60 V and higher. The thickness of the silicon nitrided layer increased with the acceleration voltages from 20 V to 60 V. Cross-sectional transmission electron microscopy (TEM) analysis indicated a Si{sub 3}N{sub 4} layer thickness of 3.1 nm was obtained at an acceleration voltage of 100 V. Moreover, it was proved that the nitrided silicon layer formed by the nitrogen NB at room temperature was effective as the passivation film in the wet etching process.

  19. Ion transport studies on the PLT tokamak during neutral beam injection

    Energy Technology Data Exchange (ETDEWEB)

    Suckewer, S.; Cavallo, A.; Cohen, S.; Daughney, C.; Denne, B.; Hinnov, E.; Hosea, J.; Hulse, R.; Hwang, D.; Schilling, G.

    1983-12-01

    Radial transport of ions during co- and counter-neutral beam heating in the PLT tokamak has been studied, using molybdenum and scandium ions as tracer elements. The time evolution of the radial profiles of several ionization stages of both elements, injected by laser blowoff during the neutral beam heating, were measured under three significantly different beam-plasma combinations. No noticeable differences in the radial profiles attributable to the beam direction were observed. However, a given injected amount resulted in considerably larger interior concentrations of the tracer element in the counter-beam heating cases, suggesting larger penetration of the plasma periphery. Computer simulation with the MIST code suggests a net inward drift of the order 10/sup 3/ cm/sec superposed to a diffusion coefficient of the order 10/sup 4/ cm/sup 2//sec for both scandium and molybdenum ions. Injection of larger amounts of the tracer element, sufficient to cause measurable central electron temperature changes, resulted in dramatic changes in ion-state distributions, making some appear peaked in the center while others disappeared. This effect could be produced with both co- and counter-beam heating, but with lesser amounts in the latter case. It is interpreted as rearrangement of the ionization balance, rather than any preferential accumulation of the injected element.

  20. Drift compression of an intense neutralized ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Roy, P.K.; Yu, S.S.; Henestroza, E.; Anders, A.; Bieniosek, F.M.; Coleman, J.; Eylon, S.; Greenway, W.G.; Leitner, M.; Logan, B.G.; Waldron, W.L.; Welch, D.R.; Thoma, C.; Sefkow, A.B.; Gilson, E.P.; Efthimion, P.C.; Davidson, R.C.

    2004-10-25

    Longitudinal compression of a tailored-velocity, intense neutralized ion beam has been demonstrated. The compression takes place in a 1-2 m drift section filled with plasma to provide space-charge neutralization. An induction cell produces a head-to-tail velocity ramp that longitudinally compresses the neutralized beam, enhancing the beam peak current by a factor of 50 and producing a pulse duration of about 3 ns. this measurement has been confirmed independently with two different diagnostic systems.

  1. Neutralization principles for the Extraction and Transport of Ion Beams

    CERN Document Server

    Riege, H

    2000-01-01

    The strict application of conventional extraction techniques of ion beams from a plasma source is characterized by a natural intensity limit determined by space charge.The extracted current may be enhanced far beyond this limit by neutralizing the space charge of the extracted ions in the first extraction gap of the source with electrons injected from the opposite side. The transverse and longitudinal emittances of a neutralized ion beam, hence its brightness, are preserved. Results of beam compensation experiments, which have been carried out with a laser ion source, are resumed for proposing a general scheme of neutralizing ion sources and their adjacent low-energy beam transport channels with electron beams. Many technical applications of high-mass ion beam neutralization technology may be identified: the enhancement of ion source output for injection into high-intensity, low-and high-energy accelerators, or ion thrusters in space technology, for the neutral beams needed for plasma heating of magnetic conf...

  2. Neutral beam dump with cathodic arc titanium gettering.

    Science.gov (United States)

    Smirnov, A; Krivenko, A S; Murakhtin, S V; Savkin, V Ya; Korepanov, S A; Putvinski, S

    2011-03-01

    An incomplete neutral beam capture can degrade the plasma performance in neutral beam driven plasma machines. The beam dumps mitigating the shine-through beam recycling must entrap and retain large particle loads while maintaining the beam-exposed surfaces clean of the residual impurities. The cathodic arc gettering, which provides high evaporation rate coupled with a fast time response, is a powerful and versatile technique for depositing clean getter films in vacuum. A compact neutral beam dump utilizing the titanium arc gettering was developed for a field-reversed configuration plasma sustained by 1 MW, 20-40 keV neutral hydrogen beams. The titanium evaporator features a new improved design. The beam dump is capable of handling large pulsed gas loads, has a high sorption capacity, and is robust and reliable. With the beam particle flux density of 5 × 10(17) H∕(cm(2) s) sustained for 3-10 ms, the beam recycling coefficient, defined as twice the ratio of the hydrogen molecular flux leaving the beam dump to the incident flux of high-energy neutral atoms, is ∼0.7. The use of the beam dump allows us to significantly reduce the recycling of the shine-through neutral beam as well as to improve the vacuum conditions in the machine.

  3. The experimental study of neutralized electron beams for electron cooling

    CERN Document Server

    Bosser, Jacques; MacCaferri, R; Molinari, G; Tranquille, G; Varenne, F; Korotaev, Yu V; Meshkov, I N; Polyakov, V A; Smirnov, A; Syresin, E M

    1996-01-01

    In this report we present the latest experimental results on electron beam neutralization. These experiments have been made at LEAR and on the JINR test bench. The main difficulty in obtaining neutralized beams resides in an instability which is dependent on the electron beam current. A number of methods have been developed in order to overcome this instability and have enabled us to further investigate the possibility of generating intense low energy electron beams for the cooling of Pb ions.

  4. Status of ITER neutral beam cell remote handling system

    Energy Technology Data Exchange (ETDEWEB)

    Sykes, N., E-mail: nick.sykes@ccfe.ac.uk [CCFE. Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Belcher, C. [Oxford Technologies Ltd, Abingdon OX14 1RJ (United Kingdom); Choi, C.-H. [ITER Organisation, CS90 046, 13067 St. Paul les Durance Cedex (France); Crofts, O. [CCFE. Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Crowe, R. [Oxford Technologies Ltd, Abingdon OX14 1RJ (United Kingdom); Damiani, C. [Fusion for Energy, C/Josep Pla 2, Torres Diagonal Litoral-B3, E-08019 Barcelona (Spain); Delavalle, S.; Meredith, L. [Oxford Technologies Ltd, Abingdon OX14 1RJ (United Kingdom); Mindham, T.; Raimbach, J. [CCFE. Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Tesini, A. [ITER Organisation, CS90 046, 13067 St. Paul les Durance Cedex (France); Van Uffelen, M. [Fusion for Energy, C/Josep Pla 2, Torres Diagonal Litoral-B3, E-08019 Barcelona (Spain)

    2013-10-15

    The ITER neutral beam cell will contain up to three heating neutral beams and one diagnostic neutral beam, and four upper ports. Though manual maintenance work is envisaged within the cell, when containment is breached, or the radiological protection is removed the maintenance must be conducted remotely. This maintenance constitutes the removal and replacement of line replaceable units, and their transport to and from a cask docked to the cell. A design of the remote handling system has been prepared to concept level which this paper describes including the development of a beam line transporter, beam source remote handling equipment, upper port remote handling equipment and equipment for the maintenance of the neutral shield. This equipment has been developed complete the planned maintenance tasks for the components of the neutral beam cell and to have inherent flexibility to enable as yet unforeseen tasks and recovery operations to be performed.

  5. Status of ITER neutral beam cell remote handling system

    CERN Document Server

    Sykes, N; Choi, C-H; Crofts, O; Crowe, R; Damiani, C; Delavalle, S; Meredith, L; Mindham, T; Raimbach, J; Tesini, A; Van Uffelen, M

    2013-01-01

    The ITER neutral beam cell will contain up to three heating neutral beams and one diagnostic neutral beam, and four upper ports. Though manual maintenance work is envisaged within the cell, when containment is breached, or the radiological protection is removed the maintenance must be conducted remotely. This maintenance constitutes the removal and replacement of line replaceable units, and their transport to and from a cask docked to the cell. A design of the remote handling system has been prepared to concept level which this paper describes including the development of a beam line transporter, beam source remote handling equipment, upper port remote handling equipment and equipment for the maintenance of the neutral shield. This equipment has been developed complete the planned maintenance tasks for the components of the neutral beam cell and to have inherent flexibility to enable as yet unforeseen tasks and recovery operations to be performed.

  6. Real-time reconfigurable counter-propagating beam-traps

    DEFF Research Database (Denmark)

    Tauro, Sandeep; Bañas, Andrew Rafael; Palima, Darwin;

    2010-01-01

    We present a versatile technique that enhances the axial stability and range in counter-propagating (CP) beam-geometry optical traps. It is based on computer vision to track objects in unison with software implementation of feedback to stabilize particles. In this paper, we experimentally...... which simulates biosamples. By working on differences rather than absolute values, this feedback based technique makes CPtrapping nullify many of the commonly encountered pertubations such as fluctuations in the laser power, vibrations due to mechanical instabilities and other distortions emphasizing...

  7. Alternative modes for optical trapping and manipulation using counter-propagating shaped beams

    DEFF Research Database (Denmark)

    Palima, Darwin; Lindballe, T.B.; Kristensen, M.V.

    2011-01-01

    Counter-propagating beams have enabled the first stable three-dimensional optical trapping of microparticles and this procedure has been enhanced and developed over the years to achieve independent and interactive manipulation of multiple particles. In this work, we analyse counter-propagating sh......Counter-propagating beams have enabled the first stable three-dimensional optical trapping of microparticles and this procedure has been enhanced and developed over the years to achieve independent and interactive manipulation of multiple particles. In this work, we analyse counter......-propagating shaped-beam traps that depart from the conventional geometry based on symmetric, coaxial counter-propagating beams. We show that projecting shaped beams with separation distances previously considered axially unstable can, in fact, enhance the axial and transverse trapping stiffnesses. We also show...... for optical trapping and manipulation using patterned counter-propagating beams, which still remains to be fully tapped....

  8. Plasma heating with multi-MeV neutral atom beams

    Energy Technology Data Exchange (ETDEWEB)

    Grisham, L.R.; Post, D.E.; Mikkelsen, D.R.; Eubank, H.P.

    1981-10-01

    We explore the utility and feasibility of neutral beams of greater than or equal to 6 AMU formed from negative ions, and also of D/sup 0/ formed from D/sup -/. The negative ions would be accelerated to approx. 1 to 2 MeV/AMU and neutralized, whereupon the neutral atoms would be used to heat and, perhaps, to drive current in magnetically confined plasmas. Such beams appear feasible and offer the promise of significant advantages relative to conventional neutral beams based on positive deuterium ions at approx. 150 keV.

  9. Recent DIII-D neutral beam calibration results

    Energy Technology Data Exchange (ETDEWEB)

    Wight, J.; Hong, R.M.; Phillips, J.

    1991-10-01

    Injected DIII-D neutral beam power is estimated based on three principle quantities: the fraction of ion beam that is neutralized in the neutralizer gas cell, the beamline transmission efficiency, and the fraction of beam reionized in the drift duct. System changes in the past few years have included a new gradient grid voltage operating point, ion source arc regulation, routine deuterium operations and new neutralizer gas flow controllers. Additionally, beam diagnostics have been improved and better calibrated. To properly characterize the beams the principle quantities have been re-measured. Two diagnostics are primarily used to measure the quantities. The beamline waterflow calorimetry system measures the neutralization efficiency and the beamline transmission efficiency, and the target tile thermocouples measure the reionization loss. An additional diagnostic, the target tile pyrometer, confirmed the reionization loss measurement. Descriptions and results of these measurements will be presented. 4 refs., 5 figs., 2 tabs.

  10. The properties of low energy neutral particles in a neutral beam source: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seung-hoon, E-mail: physh@kaist.ac.k [Department of Physics, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Yoo, Suk Jae [National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Chang, Choong-Seock [Department of Physics, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Courant Institute of Mathematical Sciences, New York University, Mercer Street, New York, NY 10012 (United States)

    2010-09-01

    Application of a hyperthermal neutral beam source is one of the candidate methods of reducing plasma induced damage problems. The neutral beam is generated by vertical collisions between energetic ions and a reflector composed of metal. However, it is difficult to measure the neutral angle and energy distribution experimentally. We simulate the hyperthermal neutral beam (HNB) generation using a molecular dynamics algorithm. In order to obtain a low energy neutral beam, ions with various energies are vertically projected onto the reflector surface. A rough surface structure that has been experimentally measured is used for a realistic simulation. The energy distributions are obtained and the ratio of energy of reflected neutral particles agrees with experimental data.

  11. Using neutral beams as a light ion beam probe (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xi, E-mail: chenxi@fusion.gat.com [Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831 (United States); Heidbrink, W. W. [University of California Irvine, Irvine, California 92697 (United States); Van Zeeland, M. A.; Pace, D. C.; Petty, C. C.; Fisher, R. K. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Kramer, G. J.; Nazikian, R. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States); Austin, M. E. [University of Texas at Austin, Austin, Texas 78712 (United States); Hanson, J. M. [Columbia University, New York, New York 10027 (United States); Zeng, L. [University of California Los Angeles, Los Angeles, California 90095 (United States)

    2014-11-15

    By arranging the particle first banana orbits to pass near a distant detector, the light ion beam probe (LIBP) utilizes orbital deflection to probe internal fields and field fluctuations. The LIBP technique takes advantage of (1) the in situ, known source of fast ions created by beam-injected neutral particles that naturally ionize near the plasma edge and (2) various commonly available diagnostics as its detector. These born trapped particles can traverse the plasma core on their inner banana leg before returning to the plasma edge. Orbital displacements (the forces on fast ions) caused by internal instabilities or edge perturbing fields appear as modulated signal at an edge detector. Adjustments in the q-profile and plasma shape that determine the first orbit, as well as the relative position of the source and detector, enable studies under a wide variety of plasma conditions. This diagnostic technique can be used to probe the impact on fast ions of various instabilities, e.g., Alfvén eigenmodes (AEs) and neoclassical tearing modes, and of externally imposed 3D fields, e.g., magnetic perturbations. To date, displacements by AEs and by externally applied resonant magnetic perturbation fields have been measured using a fast ion loss detector. Comparisons with simulations are shown. In addition, nonlinear interactions between fast ions and independent AE waves are revealed by this technique.

  12. Negative ions as a source of low energy neutral beams

    Energy Technology Data Exchange (ETDEWEB)

    Fink, J.H.

    1980-01-01

    Little consideration has been given to the impact of recent developments in negative ion source technology on the design of low energy neutral beam injectors. However, negative ion sources of improved operating efficiency, higher gas efficiency, and smaller beam divergence will lead to neutral deuterium injectors, operating at less than 100 keV, with better operating efficiencies and more compact layouts than can be obtained from positive ion systems.

  13. A 3D printed beam splitter for polar neutral molecules

    CERN Document Server

    Gordon, Sean D S

    2016-01-01

    We describe a beam splitter for polar neutral molecules. An electrostatic hexapole initially confines and guides a supersonic expansion of ammonia, and it then smoothly transforms into two bent quadrupole guides, thus splitting the molecular beam in two correlated fractions. This paves the way towards molecular beam experiments wherein one beam is modified through interactions with, e.g. a laser beam or another molecular beam, while the other one remains unmodified and serves as a reference. Because both beams originate from the same parent beam, such differential experiments can dramatically enhance the sensitivity. The highly complex electrode structure required for the beam splitter would be very difficult to build by traditional means. Instead, we introduce a new method of production: 3D printing of a plastic piece, followed by electroplating. The 3D printed piece can take any desired shape and, since the entire structure can be printed as a single piece, provides inherently precise alignment. Electroplat...

  14. Progress report on the neutral beam radiation hardening study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.D.; Condit, R.H.; Hoenig, C.L.; Wilcox, T.P.; Erickson, J.

    1978-10-01

    A neutral beam injector as presently conceived directly views the plasma it is sustaining. In turn the injector is exposed to the primary fusion neutrons plus secondary neutrons and gammas streaming back up the neutral beam duct. The intent of this work is to examine representative beam lines to see how performance and lifetimes could be affected by this radiation environment and to determine how unacceptable effects could be alleviated. Potential radiation induced problems addressed in this report have been limited to: (1) overheating of cryopanels and insulators, (2) gamma flux induced electrical conductivity increase of insulators, and (3) neutron and gamma fluence induced damage to insulator materials.

  15. Dynamics of Ion Beam Charge Neutralization by Ferroelectric Plasma Sources

    Science.gov (United States)

    Stepanov, Anton D.; Gilson, Erik P.; Grisham, Larry R.; Kaganovich, Igor D.; Davidson, Ronald C.; Ji, Qing; Persaud, Arun; Seidl, Peter A.; Schenkel, Thomas

    2016-10-01

    Ferroelectric Plasma Sources (FEPSs) can generate plasma that provides effective space-charge neutralization of intense high-perveance ion beams. Here we present experimental results on charge neutralization of a high-perveance 38 keV Ar+ beam by a FEPS plasma. By comparing the measured beam radius with the envelope model for space-charge expansion, it is shown that a charge neutralization fraction of 98% is attainable. The transverse electrostatic potential of the ion beam is reduced from 15 V before neutralization to 0.3 V, implying that the energy of the neutralizing electrons is below 0.3 eV. Near-complete charge neutralization is established 5 μs after the driving pulse is applied to the FEPS, and can last for 35 μs. It is argued that the duration of neutralization is much longer than a reasonable lifetime of the plasma produced in the sub- μs surface discharge. Measurements of current flow in the driving circuit of the FEPS suggest that plasma can be generated for tens of μs after the high voltage pulse is applied. This is confirmed by fast photography of the plasma in the 1-meter long FEPS on NDCX-II, where effective charge neutralization of the beam was achieved with the optimized FEPS timing. This work was supported by the Office of Science of the US Department of Energy under contracts DE-AC0209CH11466 (PPPL) and DE-AC0205CH11231 (LBNL).

  16. Field reversed configuration confinement enhancement through edge biasing and neutral beam injection.

    Science.gov (United States)

    Tuszewski, M; Smirnov, A; Thompson, M C; Korepanov, S; Akhmetov, T; Ivanov, A; Voskoboynikov, R; Schmitz, L; Barnes, D; Binderbauer, M W; Brown, R; Bui, D Q; Clary, R; Conroy, K D; Deng, B H; Dettrick, S A; Douglass, J D; Garate, E; Glass, F J; Gota, H; Guo, H Y; Gupta, D; Gupta, S; Kinley, J S; Knapp, K; Longman, A; Hollins, M; Li, X L; Luo, Y; Mendoza, R; Mok, Y; Necas, A; Primavera, S; Ruskov, E; Schroeder, J H; Sevier, L; Sibley, A; Song, Y; Sun, X; Trask, E; Van Drie, A D; Walters, J K; Wyman, M D

    2012-06-22

    Field reversed configurations (FRCs) with high confinement are obtained in the C-2 device by combining plasma gun edge biasing and neutral beam injection. The plasma gun creates an inward radial electric field that counters the usual FRC spin-up. The n = 2 rotational instability is stabilized without applying quadrupole magnetic fields. The FRCs are nearly axisymmetric, which enables fast ion confinement. The plasma gun also produces E × B shear in the FRC edge layer, which may explain the observed improved particle transport. The FRC confinement times are improved by factors 2 to 4, and the plasma lifetimes are extended from 1 to up to 4 ms.

  17. Study of semileptonic and leptonic neutral-current processes and of $\\mu$-polarization using counter techniques

    CERN Multimedia

    2002-01-01

    .PP This experiment will study semileptonic neutral current neutrino interactions with nucleons, using principally the dichromatic neutrino beam N1 and will make measurements of the polarization of muons produced in the WA1 experiment by neutrino-nucleon interactions, using the horn-focused broad-band neutrino The main part of the apparatus is a fine-grained target calorimeter in which the energy and direction of the hadronic jet resulting from the neutrino scattering is measured by electronic techniques. It is supplemented by a muon detector and spectrometer. The fine-grained calorimeter is used as a polarimeter for muons produced in WA1. \\\\ \\\\ The calorimeter is composed of 13 modules, each 1.2 m long and 4~m x 4~m in cross section. A module consists of six 3 m x 3 m target plates made of 8 cm thick marble with 12 cm gaps for insertion of 20 scintillation counters of 15 cm width and 3 cm thickness, 128 proportional counters of 3~x~3~cm|2 cross-section and 4~m length, and 256 streamer tubes of 0.9~x~0.9~cm|2...

  18. Alternative modes for optical trapping and manipulation using counter-propagating shaped beams

    DEFF Research Database (Denmark)

    Palima, Darwin; Lindballe, T.B.; Kristensen, M.V.;

    2011-01-01

    -propagating shaped-beam traps that depart from the conventional geometry based on symmetric, coaxial counter-propagating beams. We show that projecting shaped beams with separation distances previously considered axially unstable can, in fact, enhance the axial and transverse trapping stiffnesses. We also show...

  19. Photon trap for neutralization of negative ions beams

    CERN Document Server

    Popov, S S; Ivanov, A A; Kotelnikov, I A

    2015-01-01

    For effectively neutralization of the powerful negative ions beams of hydrogen and deuterium the photon target is considered in long time. The attractiveness of the traditional approach (Fabry-Perot resonators) to their creation is limited to a number of stringent technical requirements and large economic costs. In this paper we propose a new concept of non-resonant photon trap (storage) for creation more technologically simple optical neutralizers.

  20. Optic diagnosis of neutral beam injection on HL-1M

    Institute of Scientific and Technical Information of China (English)

    郑银甲; 冯震; 雷光玖; 姜韶风; 卢大伦; 罗俊林

    2002-01-01

    During the operation of a high-power neutral beam injection (NBI) system on the H L-1M tokamak, an optical diagnostic means using CCD camera was developed to characterize the NBI performance. The vacuum valve opening process and NBI period in the HL-1M experiment were displayed by a lot of photos taken with this means. Thus, the Hα emission profiles of the neutral beam (NB) and its interaction with plasma were given. Finally, the reason possible for plasma breakdown during NBI mode Ⅱ discharge was investigated. Therefore, this in-situ diagnosis can provide more information of the NBI.

  1. Simulations of Neutral Beam Ion Ripple Loss on EAST

    Institute of Scientific and Technical Information of China (English)

    李吉波; 丁斯晔; 吴斌; 胡纯栋

    2012-01-01

    Predictions on the ripple loss of neutral beam fast ions on EAST are investigated with a guiding center code, including both ripple and collisional effects. A 6% to 16% loss of neutral beam ions is predicted for typical EAST experiments, and a synergistic enhancement of fast ion loss is found for toroidal field (TF) ripples with collisions. The lost ions are strongly localized and will cause a maximum heat load of - 0.05 MW/m^2 on the first wall.

  2. Neutral Beam Injection for Plasma and Magnetic FieldDiagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Vainionpaa, Jaakko Hannes; Leung, Ka Ngo; Kwan, Joe W.; Levinton,Fred

    2007-08-01

    At the Lawrence Berkeley National Laboratory (LBNL) adiagnostic neutral beam injection system for measuring plasma parameters,flow velocity, and local magnetic field is being developed. High protonfraction and small divergence is essential for diagnostic neutral beams.In our design, a neutral hydrogen beam with an 8 cm x 11 cm (or smaller)elliptical beam spot at 2.5 m from the end of the extraction column isproduced. The beam will deliver up to 5 A of hydrogen beam to the targetwith a pulse width of ~;1 s, once every 1 - 2 min. The H1+ ion species ofthe hydrogen beamwill be over 90 percent. For this application, we havecompared two types of RF driven multicusp ion sources operating at 13.56MHz. The first one is an ion source with an external spiral antennabehind a dielectric RF-window. The second one uses an internal antenna insimilar ion source geometry. The source needs to generate uniform plasmaover a large (8 cm x 5 cm) extraction area. We expect that the ion sourcewith internal antenna will be more efficient at producing the desiredplasma density but might have the issue of limited antenna lifetime,depending on the duty factor. For both approaches there is a need forextra shielding to protect the dielectric materials from the backstreaming electrons. The source walls will be made of insulator materialsuch as quartz that has been observed to generate plasma with higheratomic fraction than sources with metal walls. The ion beam will beextracted and accelerated by a set of grids with slits, thus forming anarray of 6 sheet-shaped beamlets. The multiple grid extraction will beoptimized using computer simulation programs. Neutralization of the beamwill be done in neutralization chamber, which has over 70 percentneutralization efficiency.

  3. Neutral beam heating of the TFTR vacuum vessel protective plates

    Energy Technology Data Exchange (ETDEWEB)

    Sink, D.A.

    1976-04-01

    The transmission of neutral beams through plasmas expected in the Tokamak Fusion Test Reactor (TFTR) has been investigated. An analytical expression for the transmission coefficient of a 120 keV deuterium beam through a tritium plasma was used and a model for the flux profile of the TFTR Neutral Beam System designed by LBL/LLL was developed and incorporated. The plasma is assumed to have a parabolic profile and is characterized by a major radius of 310 cm, a minor radius of 57 cm, and a central plasma density of greater than or equal to 0.4 x 10/sup 14/ cm-/sup 3/. To protect the stainless steel vacuum vessel walls of the TFTR device, tungsten plates are located inside the vessel. The loading of the tungsten protective plates during normal operation is well below the neutral beam fluxes which would melt the tungsten. The TFTR Neutral Beam System will inject a total of 20 MW of 120 keV deuterium atoms from twelve sources, as well as approximately 12 MW of 60 keV deuterium atoms. The fluxes anticipated on the tungsten plates due to an unattenuated beam which would be incident at an angle of 45/sup 0/ are less than or equal to 6.5 kW/cm/sup 2/. The fluxes due to an attenuated beam are calculated to be less than or equal to 0.35 kW/cm/sup 2/. For the maximum injection time of 0.5 second, a fault condition in which the plasma was not formed at the time of injection could induce a surface temperature very near the melting point of tungsten. For the standard 0.1 second injection time anticipated for TFTR, a similar fault condition would not cause the temperature to rise to more than 2000 K which is well below the melting point (3640 K) of tungsten.

  4. Diagnostics of the ITER neutral beam test facility.

    Science.gov (United States)

    Pasqualotto, R; Serianni, G; Sonato, P; Agostini, M; Brombin, M; Croci, G; Dalla Palma, M; De Muri, M; Gazza, E; Gorini, G; Pomaro, N; Rizzolo, A; Spolaore, M; Zaniol, B

    2012-02-01

    The ITER heating neutral beam (HNB) injector, based on negative ions accelerated at 1 MV, will be tested and optimized in the SPIDER source and MITICA full injector prototypes, using a set of diagnostics not available on the ITER HNB. The RF source, where the H(-)∕D(-) production is enhanced by cesium evaporation, will be monitored with thermocouples, electrostatic probes, optical emission spectroscopy, cavity ring down, and laser absorption spectroscopy. The beam is analyzed by cooling water calorimetry, a short pulse instrumented calorimeter, beam emission spectroscopy, visible tomography, and neutron imaging. Design of the diagnostic systems is presented.

  5. Module for dielectric surfaces modification by fast neutral particles beams

    Science.gov (United States)

    Barchenko, V. T.; Lisenkov, A. A.; Babinov, N. A.

    2014-11-01

    In this paper, we describe the module for dielectric and wide-gap semiconductor surfaces modification by fast neutral beam. The module can be used for cleaning, etching or assisting of films deposition. The surface proceeding by neutral beam can prevent an accumulation of surface charge without using current compensation by inserting electrons to the beam or RF power supply. The module beside cathode and anode contains an electrode with floating potential. Insertion of the additional electrode causes electron retention in an electrostatic trap resulting the reducing of the module operating pressure. Moreover, the electrode with floating potential allows increasing the current efficient of the module. An important feature of the module is that neutralization of the ions extracted from the plasma occurs in the cathode potential well. Thereby ions that have not neutralized cannot leave nearcathode region and there are no fast ions in the output beam. Module does not contain sources of the magnetic fields or elements heated by external sources. Module operates with free cooling. Thus, the module does not need water cooling and can be freely moved in the vacuum chamber.

  6. Alfven eigenmode structure during off-axis neutral beam injection

    NARCIS (Netherlands)

    Tobias, B.; Bass, E. M.; Classen, I.G.J.; Domier, C.W.; Grierson, B. A.; Heidbrink, W. W.; N C Luhmann Jr.,; Nazikian, R.; Park, H. K.; Spong, D. A.; VanZeeland, M. A.

    2012-01-01

    The spatial structure of Alfven eigenmodes on the DIII-D tokamak is compared for contrasting fast ion deposition profiles resulting from on- and off-axis neutral beam injection (NBI). In both cases, poloidal mode rotation and eigenmode twist, or radial phase variation, are correlated with the direct

  7. 508.58 MHz synchronous universal counter for beam control system of SPring-8

    CERN Document Server

    Suzuki, H; Hara, M; Hori, T; Kawashima, Y; Ohashi, Y; Ohshima, T; Tani, N; Yonehara, H

    1999-01-01

    A synchronous universal counter was developed for beam handling and monitoring in SPring-8. It works at 508.58 MHz radio frequency and has a 30-bit width. Its two main features are a dividing function with an arbitrary positive integer and a digital delay function with a time interval over 2 s. The counter numbers all of the RF buckets of the SPring-8 storage ring from 0 to 2435. Successful installation of the counter and a signal transmission system with a low time jitters provided precise beam injection into a targeted RF bucket and furthermore into the RF buckets previously filled for addition. As an application, it can be used as a programmable digital delay module to give a reference timing for synchrotron light experiments. It can be adopted in most accelerators operated throughout the world to achieve easy beam injection. The design, performance and applications of the counter and a precise signal transmission system are described. (author)

  8. Low energy, high power hydrogen neutral beam for plasma heating

    Energy Technology Data Exchange (ETDEWEB)

    Deichuli, P.; Davydenko, V.; Ivanov, A., E-mail: ivanov@inp.nsk.su; Mishagin, V.; Sorokin, A.; Stupishin, N. [Budker Institute of Nuclear Physics, Prospect Lavrentieva 11, 630090 Novosibirsk (Russian Federation); Korepanov, S.; Smirnov, A. [Tri Alpha Energy, Inc., Foothill Ranch, California 92610 (United States)

    2015-11-15

    A high power, relatively low energy neutral beam injector was developed to upgrade of the neutral beam system of the gas dynamic trap device and C2-U experiment. The ion source of the injector produces a proton beam with the particle energy of 15 keV, current of up to 175 A, and pulse duration of a few milliseconds. The plasma emitter of the ion source is produced by superimposing highly ionized plasma jets from an array of four arc-discharge plasma generators. A multipole magnetic field produced with permanent magnets at the periphery of the plasma box is used to increase the efficiency and improve the uniformity of the plasma emitter. Multi-slit grids with 48% transparency are fabricated from bronze plates, which are spherically shaped to provide geometrical beam focusing. The focal length of the Ion Optical System (IOS) is 3.5 m and the initial beam diameter is 34 cm. The IOS geometry and grid potentials were optimized numerically to ensure accurate beam formation. The measured angular divergences of the beam are ±0.01 rad parallel to the slits and ±0.03 rad in the transverse direction.

  9. Low energy, high power hydrogen neutral beam for plasma heating

    Science.gov (United States)

    Deichuli, P.; Davydenko, V.; Ivanov, A.; Korepanov, S.; Mishagin, V.; Smirnov, A.; Sorokin, A.; Stupishin, N.

    2015-11-01

    A high power, relatively low energy neutral beam injector was developed to upgrade of the neutral beam system of the gas dynamic trap device and C2-U experiment. The ion source of the injector produces a proton beam with the particle energy of 15 keV, current of up to 175 A, and pulse duration of a few milliseconds. The plasma emitter of the ion source is produced by superimposing highly ionized plasma jets from an array of four arc-discharge plasma generators. A multipole magnetic field produced with permanent magnets at the periphery of the plasma box is used to increase the efficiency and improve the uniformity of the plasma emitter. Multi-slit grids with 48% transparency are fabricated from bronze plates, which are spherically shaped to provide geometrical beam focusing. The focal length of the Ion Optical System (IOS) is 3.5 m and the initial beam diameter is 34 cm. The IOS geometry and grid potentials were optimized numerically to ensure accurate beam formation. The measured angular divergences of the beam are ±0.01 rad parallel to the slits and ±0.03 rad in the transverse direction.

  10. Focused beams of fast neutral atoms in glow discharge plasma

    Science.gov (United States)

    Grigoriev, S. N.; Melnik, Yu. A.; Metel, A. S.; Volosova, M. A.

    2017-06-01

    Glow discharge with electrostatic confinement of electrons in a vacuum chamber allows plasma processing of conductive products in a wide pressure range of p = 0.01 - 5 Pa. To assist processing of a small dielectric product with a concentrated on its surface beam of fast neutral atoms, which do not cause charge effects, ions from the discharge plasma are accelerated towards the product and transformed into fast atoms. The beam is produced using a negatively biased cylindrical or a spherical grid immersed in the plasma. Ions accelerated by the grid turn into fast neutral atoms at p > 0.1 Pa due to charge exchange collisions with gas atoms in the space charge sheaths adjoining the grid. The atoms form a diverging neutral beam and a converging beam propagating from the grid in opposite directions. The beam propagating from the concave surface of a 0.24-m-wide cylindrical grid is focused on a target within a 10-mm-wide stripe, and the beam from the 0.24-m-diameter spherical grid is focused within a 10-mm-diameter circle. At the bias voltage U = 5 kV and p ˜ 0.1 Pa, the energy of fast argon atoms is distributed continuously from zero to eU ˜ 5 keV. The pressure increase to 1 Pa results in the tenfold growth of their equivalent current and a decrease in the mean energy by an order of magnitude, which substantially raises the efficiency of material etching. Sharpening by the beam of ceramic knife-blades proved that the new method for the generation of concentrated fast atom beams can be effectively used for the processing of dielectric materials in vacuum.

  11. Measurement of diagnostic neutral beam parameters on J-TEXT

    Science.gov (United States)

    Wang, J. R.; Cheng, Z. F.; Li, Z.; Li, Y.; Luo, J.; Zhang, X. L.; Zhuang, G.

    2016-11-01

    A Doppler frequency shift spectrum (DFSS) system composed of two spectrometers has been developed for the joint Texas experimental tokamak to measure diagnostic neutral beam parameters including the beam energy fractions, intensity distributions, and divergences. The beam energy fractions are derived from measurements of H-alpha (Hα) emission using collisional excitation cross sections. The beam intensity distributions are obtained using an 11-channel measurement with a reconstruction technique. The beam divergences are obtained from spectrum broadening and geometric calculations. The results of preliminary investigations indicate that the DFSS system works well and can be used to obtain all of these parameters simultaneously. According to the preliminary experiment, the one-third energy fraction has the largest proportion (about 45%) of the beam energy and the full energy fraction is about 10%. The beam diameter is about 8.1 cm at a distance of 2.04 m from the accelerator. The beam divergence angle is about 3.3°. The current beam parameters are insufficient for charge-exchange measurements.

  12. ITER neutral beam system US conceptual design. Final vesion

    Energy Technology Data Exchange (ETDEWEB)

    Purgalis, P.

    1990-09-01

    In this document we present the US conceptual design of a neutral beam system for International Thermonuclear Experimental Reactor (ITER). The design incorporates a barium surface conversion D{sup {minus}} source feeding a linear array of accelerator channels. The system uses a dc accelerator with electrostatic quadrupoles for strong focusing. A high voltage power supply that is integrated with the accelerator is presented as an attractive option. A gas neutralizer is used and residual ions exiting the neutralizer are deflected to water-cooled dumps. Cryopanels are located at the accelerator exit to pump excess gas from the source and the neutralizer, and in the ion dump cavity to pump re-neutralized ions and neutralizer gas. All the above components are packaged in compact identical, independent modules which can be removed for remote maintenance. The neutral beam system delivers 75 MW of DO at 1.3 MeV, into three ports with a total of 9 modules arranged in stacks of three modules per port . To increase reliability each module is designed to deliver up to 10 MW; this allows eight modules operating at partial capacity to deliver the required power in the event one module is out of service, and provides 20% excess capacity to improve availability. Radiation protection is provided by shielding and by locating critical components in the source and accelerator 46.5 m from the torus centerline. Neutron shielding in the drift duct and neutralizer provides the added feature of limiting conductance and thus reducing gas flow to and from the torus.

  13. Investigation of accelerated neutral atom beams created from gas cluster ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Kirkpatrick, A., E-mail: akirkpatrick@exogenesis.us [Exogenesis Corporation, 20 Fortune Drive, Billerica, MA 01821 (United States); Kirkpatrick, S.; Walsh, M.; Chau, S.; Mack, M.; Harrison, S.; Svrluga, R.; Khoury, J. [Exogenesis Corporation, 20 Fortune Drive, Billerica, MA 01821 (United States)

    2013-07-15

    A new concept for ultra-shallow processing of surfaces known as accelerated neutral atom beam (ANAB) technique employs conversion of energetic gas cluster ions produced by the gas cluster ion beam (GCIB) method into intense collimated beams of coincident neutral gas atoms having controllable average energies from less than 10 eV per atom to beyond 100 eV per atom. A beam of accelerated gas cluster ions is first produced as is usual in GCIB, but conditions within the source ionizer and extraction regions are adjusted such that immediately after ionization and acceleration the clusters undergo collisions with non-ionized gas atoms. Energy transfer during these collisions causes the energetic cluster ions to release many of their constituent atoms. An electrostatic deflector is then used to eliminate charged species, leaving the released neutral atoms to still travel collectively at the same velocities they had as bonded components of their parent clusters. Upon target impact, the accelerated neutral atom beams produce effects similar to those normally associated with GCIB, but to shallower depths, with less surface damage and with superior subsurface interfaces. The paper discusses generation and characterization of the accelerated neutral atom beams, describes interactions of the beams with target surfaces, and presents examples of ongoing work on applications for biomedical devices.

  14. Investigation of accelerated neutral atom beams created from gas cluster ion beams

    Science.gov (United States)

    Kirkpatrick, A.; Kirkpatrick, S.; Walsh, M.; Chau, S.; Mack, M.; Harrison, S.; Svrluga, R.; Khoury, J.

    2013-07-01

    A new concept for ultra-shallow processing of surfaces known as accelerated neutral atom beam (ANAB) technique employs conversion of energetic gas cluster ions produced by the gas cluster ion beam (GCIB) method into intense collimated beams of coincident neutral gas atoms having controllable average energies from less than 10 eV per atom to beyond 100 eV per atom. A beam of accelerated gas cluster ions is first produced as is usual in GCIB, but conditions within the source ionizer and extraction regions are adjusted such that immediately after ionization and acceleration the clusters undergo collisions with non-ionized gas atoms. Energy transfer during these collisions causes the energetic cluster ions to release many of their constituent atoms. An electrostatic deflector is then used to eliminate charged species, leaving the released neutral atoms to still travel collectively at the same velocities they had as bonded components of their parent clusters. Upon target impact, the accelerated neutral atom beams produce effects similar to those normally associated with GCIB, but to shallower depths, with less surface damage and with superior subsurface interfaces. The paper discusses generation and characterization of the accelerated neutral atom beams, describes interactions of the beams with target surfaces, and presents examples of ongoing work on applications for biomedical devices.

  15. Evidence of locally enhanced target heating due to instabilities of counter-streaming fast electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Koester, Petra; Cecchetti, Carlo A. [Intense Laser Irradiation Laboratory at INO, CNR, Pisa (Italy); Booth, Nicola; Woolsey, Nigel [Physics Department, University of York, York (United Kingdom); Chen, Hui [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Evans, Roger G. [Imperial College London, London (United Kingdom); Gregori, Gianluca; Li, Bin; Mithen, James; Murphy, Christopher D. [Physics Department, University of Oxford, Oxford (United Kingdom); Labate, Luca; Gizzi, Leonida A. [Intense Laser Irradiation Laboratory at INO, CNR, Pisa (Italy); INFN, Sezione di Pisa, Pisa (Italy); Levato, Tadzio [Intense Laser Irradiation Laboratory at INO, CNR, Pisa (Italy); University of Rome Tor Vergata, Rome (Italy); Makita, Mikako; Riley, David [Physics Department, Queens University Belfast, Belfast (United Kingdom); Notley, Margaret; Pattathil, Rajeev [Rutherford Appleton Laboratory, STFC, Didcot (United Kingdom)

    2015-02-15

    The high-current fast electron beams generated in high-intensity laser-solid interactions require the onset of a balancing return current in order to propagate in the target material. Such a system of counter-streaming electron currents is unstable to a variety of instabilities such as the current-filamentation instability and the two-stream instability. An experimental study aimed at investigating the role of instabilities in a system of symmetrical counter-propagating fast electron beams is presented here for the first time. The fast electron beams are generated by double-sided laser-irradiation of a layered target foil at laser intensities above 10{sup 19 }W/cm{sup 2}. High-resolution X-ray spectroscopy of the emission from the central Ti layer shows that locally enhanced energy deposition is indeed achieved in the case of counter-propagating fast electron beams.

  16. Status of the ITER heating neutral beam system

    Science.gov (United States)

    Hemsworth, R.; Decamps, H.; Graceffa, J.; Schunke, B.; Tanaka, M.; Dremel, M.; Tanga, A.; DeEsch, H. P. L.; Geli, F.; Milnes, J.; Inoue, T.; Marcuzzi, D.; Sonato, P.; Zaccaria, P.

    2009-04-01

    The ITER neutral beam (NB) injectors are the first injectors that will have to operate under conditions and constraints similar to those that will be encountered in a fusion reactor. These injectors will have to operate in a hostile radiation environment and they will become highly radioactive due to the neutron flux from ITER. The injectors will use a single large ion source and accelerator that will produce 40 A 1 MeV D- beams for pulse lengths of up to 3600 s. Significant design changes have been made to the ITER heating NB (HNB) injector over the past 4 years. The main changes are: Modifications to allow installation and maintenance of the beamline components with an overhead crane. The beam source vessel shape has been changed and the beam source moved to allow more space for the connections between the 1 MV bushing and the beam source. The RF driven negative ion source has replaced the filamented ion source as the reference design. The ion source and extractor power supplies will be located in an air insulated high voltage (-1 MV) deck located outside the tokamak building instead of inside an SF6 insulated HV deck located above the injector. Introduction of an all metal absolute valve to prevent any tritium in the machine to escape into the NB cell during maintenance. This paper describes the status of the design as of December 2008 including the above mentioned changes. The very important power supply system of the neutral beam injectors is not described in any detail as that merits a paper beyond the competence of the present authors. The R&D required to realize the injectors described in this paper must be carried out on a dedicated neutral beam test facility, which is not described here.

  17. Ferroelectric Plasma Source for Heavy Ion Beam Charge Neutralization

    CERN Document Server

    Efthimion, Philip; Gilson, Erik P; Grisham, Larry; Logan, B G; Waldron, William; Yu, Simon

    2005-01-01

    Plasmas are employed as a medium for charge neutralizing heavy ion beams to allow them to focus to a small spot size. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length ~ 0.1-1 m would be suitable. To produce 1 meter plasma, large-volume plasma sources based upon ferroelectric ceramics are being considered. These sources have the advantage of being able to increase the length of the plasma and operate at low neutral pressures. The source will utilize the ferroelectric ceramic BaTiO3 to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) will be covered with ceramic. High voltage (~ 1-5 kV) is applied between the drift tube and the front surface of the ceramic by placing a wire grid on the front surface. A prototype ferroelectric source 20 cm long produced plasma densities ~ 5x1011 cm-3. The source was integrated into the experiment and successfully charge neutralized the K ion beam. Presently, the 1 meter source ...

  18. The ITER Neutral Beam Test Facility towards SPIDER operation

    Science.gov (United States)

    Toigo, V.; Dal Bello, S.; Gaio, E.; Luchetta, A.; Pasqualotto, R.; Zaccaria, P.; Bigi, M.; Chitarin, G.; Marcuzzi, D.; Pomaro, N.; Serianni, G.; Agostinetti, P.; Agostini, M.; Antoni, V.; Aprile, D.; Baltador, C.; Barbisan, M.; Battistella, M.; Boldrin, M.; Brombin, M.; Dalla Palma, M.; De Lorenzi, A.; Delogu, R.; De Muri, M.; Fellin, F.; Ferro, A.; Gambetta, G.; Grando, L.; Jain, P.; Maistrello, A.; Manduchi, G.; Marconato, N.; Pavei, M.; Peruzzo, S.; Pilan, N.; Pimazzoni, A.; Piovan, R.; Recchia, M.; Rizzolo, A.; Sartori, E.; Siragusa, M.; Spada, E.; Spagnolo, S.; Spolaore, M.; Taliercio, C.; Valente, M.; Veltri, P.; Zamengo, A.; Zaniol, B.; Zanotto, L.; Zaupa, M.; Boilson, D.; Graceffa, J.; Svensson, L.; Schunke, B.; Decamps, H.; Urbani, M.; Kushwah, M.; Chareyre, J.; Singh, M.; Bonicelli, T.; Agarici, G.; Garbuglia, A.; Masiello, A.; Paolucci, F.; Simon, M.; Bailly-Maitre, L.; Bragulat, E.; Gomez, G.; Gutierrez, D.; Mico, G.; Moreno, J.-F.; Pilard, V.; Chakraborty, A.; Baruah, U.; Rotti, C.; Patel, H.; Nagaraju, M. V.; Singh, N. P.; Patel, A.; Dhola, H.; Raval, B.; Fantz, U.; Fröschle, M.; Heinemann, B.; Kraus, W.; Nocentini, R.; Riedl, R.; Schiesko, L.; Wimmer, C.; Wünderlich, D.; Cavenago, M.; Croci, G.; Gorini, G.; Rebai, M.; Muraro, A.; Tardocchi, M.; Hemsworth, R.

    2017-08-01

    SPIDER is one of two projects of the ITER Neutral Beam Test Facility under construction in Padova, Italy, at the Consorzio RFX premises. It will have a 100 keV beam source with a full-size prototype of the radiofrequency ion source for the ITER neutral beam injector (NBI) and also, similar to the ITER diagnostic neutral beam, it is designed to operate with a pulse length of up to 3600 s, featuring an ITER-like magnetic filter field configuration (for high extraction of negative ions) and caesium oven (for high production of negative ions) layout as well as a wide set of diagnostics. These features will allow a reproduction of the ion source operation in ITER, which cannot be done in any other existing test facility. SPIDER realization is well advanced and the first operation is expected at the beginning of 2018, with the mission of achieving the ITER heating and diagnostic NBI ion source requirements and of improving its performance in terms of reliability and availability. This paper mainly focuses on the preparation of the first SPIDER operations—integration and testing of SPIDER components, completion and implementation of diagnostics and control and formulation of operation and research plan, based on a staged strategy.

  19. New ion source for KSTAR neutral beam injection system.

    Science.gov (United States)

    Kim, Tae-Seong; Jeong, Seung Ho; In, Sang-Ryul

    2012-02-01

    The neutral beam injection system (NBI-1) of the KSTAR tokamak can accommodate three ion sources; however, it is currently equipped with only one prototype ion source. In the 2010 and 2011 KSTAR campaigns, this ion source supplied deuterium neutral beam power of 0.7-1.6 MW to the KSTAR plasma with a beam energy of 70-100 keV. A new ion source will be prepared for the 2012 KSTAR campaign with a much advanced performance compared with the previous one. The newly designed ion source has a very large transparency (∼56%) without deteriorating the beam optics, which is designed to deliver a 2 MW injection power of deuterium beams at 100 keV. The plasma generator of the ion source is of a horizontally cusped bucket type, and the whole inner wall, except the cathode filaments and plasma grid side, functions as an anode. The accelerator assembly consists of four multi-circular aperture grids made of copper and four electrode flanges made of aluminum alloy. The electrodes are insulated using PEEK. The ion source will be completed and tested in 2011.

  20. Heavy Neutral Beam Probe for Edge Plasma Analysis in Tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Castracane, J.

    2001-01-04

    The Heavy Neutral Beam Probe (HNBP) developed initially with DOE funding under the Small Business Innovation Research (SBIR) program was installed on the Tokamak de Varennes (TdeV) at the CCFM. This diagnostic was designed to perform fundamental measurements of edge plasma properties. The hardware was capable of measuring electron density and potential profiles with high spatial and temporal resolution. Fluctuation spectra for these parameters were obtained with HNBP for transport studies.

  1. Conceptual design for the ZEPHYR neutral-beam injection system

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, W.S.; Elischer, V.P.; Goldberg, D.A.; Hopkins, D.B.; Jacobson, V.L.; Lou, K.H.; Tanabe, J.T.

    1981-03-01

    In June 1980, the Lawrence Berkeley Laboratory began a conceptual design study for a neutral beam injection system for the ZEPHYR ignition tokamak proposed by the Max-Planck-Institut fur Plasmaphysik in Garching, Germany. The ZEPHYR project was cancelled, and the LBL design effort concluded prematurely in January 1981. This report describes the conceptual design as it existed at that time, and gives brief consideration to a schedule, but does not deal with costs.

  2. A STUDY ON THE COUNTER-INTUITIVE BEHAVIORS OF PIN-ENDED BEAMS UNDER PROJECTILE IMPACT

    Institute of Scientific and Technical Information of China (English)

    Li Haiwang; Qin Dongqi

    2006-01-01

    The counter-intuitive behaviors of pin-ended beams under the projectile impact are investigated with ANSYS/LS-DYNA in this paper. It studies in detail their displacement-time history curves, final deformed shapes, energy relationships and projectile impact velocity ranges related to their counterintuitive behaviors. The influences of the impact positions on their counterintuitive behaviors are also discussed. The results show that no matter where the impact position on the beam is, the counter-intuitive behaviors of pinned beams will occur as long as the impacting velocity lies within a proper range. Corresponding to the occurring of the counterintuitive behaviors, the rebounding number in the displacement history curves of the beams decreases from a few times to zero with an increase of the impact velocity. The final deformation modes of the beam corresponding to the counter-intuitive behaviors will appear in symmetrical and unsymmetrical forms no matter where the impact position is; the impact velocity of the first-occurring of the counter-intuitive behaviors of the beam increases slowly with the deviation of the impact position away from the mid-span.

  3. Dense Metal Plasma in a Solenoid for Ion Beam Neutralization

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre; Kauffeldt, Marina; Oks, Efim M.; Roy, Prabir K.

    2010-10-30

    Space-charge neutralization is required to compress and focus a pulsed, high-current ion beam on a target for warm dense matter physics or heavy ion fusion experiments. We described approaches to produce dense plasma in and near the final focusing solenoid through which the ion beam travels, thereby providing an opportunity for the beam to acquire the necessary space-charge compensating electrons. Among the options are plasma injection from pulsed vacuum arc sources located outside the solenoid, and using a high current (> 4 kA) pulsed vacuum arc plasma from a ring cathode near the edge of the solenoid. The plasma distribution is characterized by photographic means, by an array of movable Langmuir probes, by a small single probe, and by evaluating Stark broadening of the Balmer H beta spectral line. In the main approach described here, the plasma is produced at several cathode spots distributed azimuthally on the ring cathode. It is shown that the plasma is essentially hollow, as determined by the structure of the magnetic field, though the plasma density exceeds 1014 cm-3 in practically all zones of the solenoid volume if the ring electrode is placed a few centimeters off the center of the solenoid. The plasma is non-uniform and fluctuating, however, since its density exceeds the ion beam density it is believed that this approach could provide a practical solution to the space charge neutralization challenge.

  4. The ITER neutral beam front end components integration

    Energy Technology Data Exchange (ETDEWEB)

    Urbani, M., E-mail: marc.urbani@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Hemsworth, R.; Schunke, B.; Graceffa, J.; Delmas, E.; Svensson, L.; Boilson, D. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Krylov, A.; Panasenkov, A. [RRC Kurchatov Institute, 1, Kurchatov Square, Moscow 123182 (Russian Federation); Agarici, G. [Fusion For Energy, C/Josep Pla 2, Torres Diagonal Litoral-B3, E-08019 Barcelona (Spain); Stafford Allen, R.; Jones, C.; Kalsey, M.; Muir, A.; Milnes, J. [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Geli, F. [FGI Consulting, Le Garde d’Estienne, 4565 route du Puy Sainte Reparade, 13540 Puyricard (France); Sherlock, P. [AMEC Limited, Booths Park Chelford Road, Knutsford Cheshire WA16 8QZ (United Kingdom)

    2013-10-15

    The neutral beam (NB) system for ITER is composed of two heating neutral beam injectors (HNBs) and a diagnostic neutral beam injector (DNB). A third HNB can be installed as a future up-grade. This paper will present the design development of the components between the injectors and the tokamak; the so-called ‘front end components’: the drift duct consists of the NB bellows and the drift duct liner, the vacuum vessel pressure suppression system box (VVPSS box), the absolute valve, and the fast shutter. These components represent the key links between the ITER tokamak and the vessels of the NB injectors. The design of these components is demanding due to the different loads that these components will have to stand. The paper will describe the different design solutions which have to be implemented regarding the primary vacuum confinement, the power handling capability and the remote maintenance operations. The sizes of the components are determined by the large cross section of the neutral beam. The power handling capability is driven by the anticipated re-ionization of the neutral beam and the electromagnetic fields in this region. The drift duct bellows (with an inner diameter of 2.5 m) shall guarantee a leak tight vacuum enclosure during the vertical and radial displacements of the ITER vacuum vessel. The conductance of the VVPSS box must be maximized in the available space. The absolute valve remains a challenging development. The total leak rate through the valve must be ≤1 × 10{sup −8} Pa m{sup 3}/s when the valve is closed. Due to the radiation environment, the seals of the gate valve will be metallic. An R and D program has been launched to develop a suitable metallic seal solution with the required dimensions. The maximum allowed closing time for the fast shutter shall be less than 1 s. For all these components the leak tightness will be guaranteed by a welded lip seal and the mechanical stability by bolted structures.

  5. The influence of grid positioning on the beam optics in the neutral beam injectors for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Veltri, Pierluigi, E-mail: pierluigi.veltri@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, Padova (Italy); INFN—Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro, Padova (Italy); Agostinetti, Piero; Marcuzzi, Diego; Sartori, Emanuele; Serianni, Gianluigi [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, Padova (Italy)

    2016-06-15

    Neutral beam injectors are routinely used to increase the ion temperature in magnetically confined plasmas. Typically, the beam is produced by neutralizing a bundle of hundreds of ion beamlets, energized in a multi-grid multi-stage accelerator. Precise aiming of each beamlet is required in order to focus the full beam to the plasma, avoiding any interception with beamline surfaces and with the beam duct. This paper describes the effects of grid in-plane and out-of-plane displacements (mispositioning, thermal expansion, grid tilting, etc…) in the case of the MITICA electrostatic accelerator, which is the full scale prototype of the ITER heating neutral beam injector. Various simulations have been carried out with the OPERA 3D code, by self-consistently simulating the beam charged particles travelling in an externally applied electric and magnetic field. The accelerator grids act like a series of electrostatic lenses, and produce a net deflection of the particles when one or more grids are offset. The numerical simulations were used to evaluate the “steering constant” of each grid and also showed that the linear superposition of effects was applicable, multiple causes of mispositioning are combined and used to quantify the overall effect in terms of beam misalignment.

  6. Assembly process of the ITER neutral beam injectors

    Energy Technology Data Exchange (ETDEWEB)

    Graceffa, J., E-mail: joseph.graceffa@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul lez Durance (France); Boilson, D.; Hemsworth, R.; Petrov, V.; Schunke, B.; Urbani, M. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul lez Durance (France); Pilard, V. [Fusion for Energy, C/ Josep Pla, n°2, Torres Diagonal Litoral, Edificio B3, 08019 Barcelona (Spain)

    2013-10-15

    The ITER neutral beam (NB) injectors are used for heating and diagnostics operations. There are 4 injectors in total, 3 heating neutral beam injectors (HNBs) and one diagnostic neutral beam injector (DNB). Two HNBs and the DNB will start injection into ITER during the hydrogen/helium phase of ITER operations. A third HNB is considered as an upgrade to the ITER heating systems, and the impact of the later installation and use of that injector have to be taken into account when considering the installation and assembly of the whole NB system. It is assumed that if a third HNB is to be installed, it will be installed before the nuclear phase of the ITER project. The total weight of one injector is around 1200 t and it is composed of 18 main components and 36 sets of shielding plates. The overall dimensions are length 20 m, height 10 m and width 5 m. Assembly of the first two HNBs and the DNB will start before the first plasma is produced in ITER, but as the time required to assemble one injector is estimated at around 1.5 year, the assembly will be divided into 2 steps, one prior to first plasma, and the second during the machine second assembly phase. To comply with this challenging schedule the assembly sequence has been defined to allow assembly of three first injectors in parallel. Due to the similar design between the DNB and HNBs it has been decided to use the same tools, which will be designed to accommodate the differences between the two sets of components. This reduces the global cost of the assembly and the overall assembly time for the injector system. The alignment and positioning of the injectors is a major consideration for the injector assembly as the alignment of the beamline components and the beam source are critical if good injector performance is to be achieved. The theoretical axes of the beams are defined relative to the duct liners which are installed in the NB ports. The concept adopted to achieve the required alignment accuracy is to use the

  7. Fast ion behavior during neutral beam injection in ATF

    Energy Technology Data Exchange (ETDEWEB)

    Wade, M.R.; Thomas, C.E.; Colchin, R.J.; Rome, J.A.; England, A.C.; Fowler, R.H. [Oak Ridge National Lab., TN (United States); Aceto, S.C. [Rensselaer Polytechnic Inst., Troy, NY (United States)

    1993-09-01

    In stellarators, single-particle confinement properties can be more complex than in their tokamak counterparts. Fast-ion behavior in tokamaks has been well characterized through an abundance of measurements on various devices and in general has been shown to be consistent with classical slowing-down theory, although anomalous ion behavior has been observed during intense beam injection in ISX-B, during fishbone instabilities in PDX, and in experiments on TFR. In contrast, fast ion behavior in stellarators is not as wel established experimentally with the primary experiments to date focusing o near-perpendicular or perpendicular neutral beam injection (NBI) on the Wendelstein 7-A stellarator (91 and Heliotron-E. This paper addresses fast-ion confinement properties in a large-aspect-ratio, moderate-shear stellarator, the Advanced Toroidal Facility, during tangential NBI. The primary data used in this study are the experimentally measured energy spectra of charge-exchange neutrals escaping from the plasma, using a two-dimensional scanning neutral particle analyzer. This diagnostic method is well established, having been used on several devices since the early 1970`s. Various aspects of fast-ion behavior are investigated by comparing these data with computed theoretical spectra based on energeticion distributions derived from the fastion Fokker-Planck equation. Ion orbits are studied by computer orbit following, by the computation of J* surfaces, and by Monte Carlo calculations.

  8. Beam Phase Space of an Intense Ion Beam in a Neutralizing Plasma

    Science.gov (United States)

    Seidl, Peter A.; Bazouin, Guillaume; Beneytout, Alice; Lidia, Steven M.; Vay, Jean-Luc; Grote, David P.

    2011-10-01

    The Neutralized Drift Compression Experiment (NDCX-I) generates high intensity ion beams to explore warm dense matter physics. Transverse final focusing is accomplished with an 8-Tesla, 10-cm long pulsed solenoid magnet combined with a background neutralizing plasma to effectively cancel the space charge field of the ion beam. We report on phase space measurements of the beam before the neutralization channel and of the focused ion beam at the target plane. These are compared to WARP particle-in-cell simulations of the ion beam propagation through the focusing system and neutralizing plasma. Due to the orientation of the plasma sources with respect to the focusing magnet, the plasma distribution within the final focusing lens is strongly affected by the magnetic field, an effect which can influence the peak intensity at the target and which is included in the model of the experiment. Work performed under auspices of U.S. DoE by LLNL, LBNL under Contracts DE-AC52-07NA27344, DE-AC02-05CH1123.

  9. A space-charge-neutralizing plasma for beam drift compression

    Science.gov (United States)

    Roy, P. K.; Seidl, P. A.; Anders, A.; Bieniosek, F. M.; Coleman, J. E.; Gilson, E. P.; Greenway, W.; Grote, D. P.; Jung, J. Y.; Leitner, M.; Lidia, S. M.; Logan, B. G.; Sefkow, A. B.; Waldron, W. L.; Welch, D. R.

    2009-07-01

    Simultaneous radial focusing and longitudinal compression of intense ion beams are being studied to heat matter to the warm dense matter, or strongly coupled plasma regime. Higher compression ratios can be achieved if the beam compression takes place in a plasma-filled drift region in which the space-charge forces of the ion beam are neutralized. Recently, a system of four cathodic arc plasma sources has been fabricated and the axial plasma density has been measured. A movable plasma probe array has been developed to measure the radial and axial plasma distribution inside and outside of a ˜10-cm-long final focus solenoid (FFS). Measured data show that the plasma forms a thin column of diameter ˜5 mm along the solenoid axis when the FFS is powered with an 8 T field. Measured plasma density of ⩾1×10 13 cm -3 meets the challenge of np/ Znb>1, where np and nb are the plasma and ion beam density, respectively, and Z is the mean ion charge state of the beam ions.

  10. Predictive Simulations of ITER Including Neutral Beam Driven Toroidal Rotation

    Energy Technology Data Exchange (ETDEWEB)

    Halpern, Federico D.; Kritz, Arnold H.; Bateman, Glenn; Pankin, Alexei Y.; Budny, Robert V.; McCune, Douglas C.

    2008-06-16

    Predictive simulations of ITER [R. Aymar et al., Plasma Phys. Control. Fusion 44, 519 2002] discharges are carried out for the 15 MA high confinement mode (H-mode) scenario using PTRANSP, the predictive version of the TRANSP code. The thermal and toroidal momentum transport equations are evolved using turbulent and neoclassical transport models. A predictive model is used to compute the temperature and width of the H-mode pedestal. The ITER simulations are carried out for neutral beam injection (NBI) heated plasmas, for ion cyclotron resonant frequency (ICRF) heated plasmas, and for plasmas heated with a mix of NBI and ICRF. It is shown that neutral beam injection drives toroidal rotation that improves the confinement and fusion power production in ITER. The scaling of fusion power with respect to the input power and to the pedestal temperature is studied. It is observed that, in simulations carried out using the momentum transport diffusivity computed using the GLF23 model [R.Waltz et al., Phys. Plasmas 4, 2482 (1997)], the fusion power increases with increasing injected beam power and central rotation frequency. It is found that the ITER target fusion power of 500 MW is produced with 20 MW of NBI power when the pedesta temperature is 3.5 keV. 2008 American Institute of Physics. [DOI: 10.1063/1.2931037

  11. COUNTER PROPAGATION OF ELECTRON AND CO2 LASER BEAMS IN A PLASMA CHANNEL.

    Energy Technology Data Exchange (ETDEWEB)

    HIROSE,T.; POGORELSKY,I.V.; BEN ZVI,I.; YAKIMENKO,V.; KUSCHE,K.; SIDDONS,P.; KUMITA,T.; KAMIYA,Y.; ZIGLER,A.; GREENBERG,B.; ET AL

    2002-11-12

    A high-energy CO{sub 2} laser is channeled in a capillary discharge. Occurrence of guiding conditions at a relatively low plasma density (<10{sup 18} cm{sup -3}) is confirmed by MHD simulations. Divergence of relativistic electron beam changes depending on the plasma density. Counter-propagation of the electron and laser beams inside the plasma channel results in intense x-ray generation.

  12. Formation and sustainment of field reversed configuration (FRC) plasmas by spheromak merging and neutral beam injection

    Science.gov (United States)

    Yamada, Masaaki

    2016-03-01

    This paper briefly reviews a compact toroid reactor concept that addresses critical issues for forming, stabilizing and sustaining a field reversed configuration (FRC) with the use of plasma merging, plasma shaping, conducting shells, neutral beam injection (NBI). In this concept, an FRC plasma is generated by the merging of counter-helicity spheromaks produced by inductive discharges and sustained by the use of neutral beam injection (NBI). Plasma shaping, conducting shells, and the NBI would provide stabilization to global MHD modes. Although a specific FRC reactor design is outside the scope of the present paper, an example of a promising FRC reactor program is summarized based on the previously developed SPIRIT (Self-organized Plasmas by Induction, Reconnection and Injection Techniques) concept in order to connect this concept to the recently achieved the High Performance FRC plasmas obtained by Tri Alpha Energy [Binderbauer et al, Phys. Plasmas 22,056110, (2015)]. This paper includes a brief summary of the previous concept paper by M. Yamada et al, Plasma Fusion Res. 2, 004 (2007) and the recent experimental results from MRX.

  13. Control System of Neutral Beam Injection on HT-7

    Institute of Scientific and Technical Information of China (English)

    Wang Yongjun; Hu Chundong; Liu Zhimin; Liu Sheng; Song Shihua; Yang Daoye

    2005-01-01

    Neutral Beam Injection control system (NBICS) is constructed to measure the plasma current, Magnet current, vacuum pressure, cryopump temperature, control water cooling, filament voltage, and power supply, etc. The NBICS, consisting mainly of a Programmable Logic Controller (PLC) subsystem, data acquisition and processing subsystem and cryopump and vacuum pressure monitoring subsystem, has successfully been used on a NBI device. In this article, the design of NBICS on HT-7 is discussed and each subsystem is described in particular.In addition, some experimental results are reported which are very important data for further research related to the HT-7 tokamak.

  14. Neutral Beam Injection Experiments in the HL-1M Tokamak

    Institute of Scientific and Technical Information of China (English)

    严龙文; 雷光玖; 钟光武; 江涛; 周艳; 姜韶风; 丁玄同; 周才品; 刘永

    2003-01-01

    Neutral beam injection (NBI) experiments have been carried out with two operation modes of a bucket ion source in the HL-1M tokamak. During the first mode, more than 30% rise in ion temperature above the Ohmic level is routinely achieved after NBI power about 0. 5 MW is injected. Ion temperature only increases 20-30% for the second operation mode, which is often limited by current termination. The heating effects of the NBI have been analysed experimentally and theoretically. The performance of the NBI system is well described.

  15. Neutral atom beam technique enhances bioactivity of PEEK

    Energy Technology Data Exchange (ETDEWEB)

    Khoury, Joseph, E-mail: jkhoury@exogenesis.us [Exogenesis Corporation, Billerica, MA 01821 (United States); Kirkpatrick, Sean R.; Maxwell, Melissa; Cherian, Raymond E.; Kirkpatrick, Allen; Svrluga, Richard C. [Exogenesis Corporation, Billerica, MA 01821 (United States)

    2013-07-15

    Polyetheretherketone (PEEK) is currently gaining popularity in orthopedic and spinal applications but has potential drawbacks in use. PEEK is biocompatible, similar in elasticity to bone, and radiolucent; however, it has been shown to be inert and does not integrate well with bone. Recent efforts have focused on increasing the bioactivity of PEEK by modifying the surface to improve the bone-implant interface. We have employed a novel Accelerated Neutral Atom Beam technique (ANAB) to enhance the bioactivity of PEEK. ANAB employs an intense beam of cluster-like packets of accelerated unbonded neutral argon (Ar) gas atoms. These beams are created by first producing a highly energetic Gas Cluster Ion Beam (GCIB) comprised of van der Waals bonded Ar atoms, then transferring energy to the clusters so as to cause release of most of the interatomic bonds, and finally deflecting away the remaining electrically charged cluster cores of still bonded atoms. We identified that ANAB treatment of PEEK results in nanometer scale surface modifications as well as increased surface hydrophilicity. Human osteoblasts seeded onto the surface of ANAB-treated PEEK exhibited enhanced growth as compared to control PEEK as evidenced by cell proliferation assays and microscopy. This increase in bioactivity resulted in cell proliferation levels comparable to native titanium. An in vivo study using a rat calvarial critical size defect model revealed enhanced osseointegration where bone tissue formation was evident only on the ANAB treated PEEK. Taken together, these data suggest that ANAB treatment of PEEK has the potential to enhance its bioactivity, resulting in bone formation and significantly decreasing osseointegration time of orthopedic and spinal implants.

  16. Theoretical analysis of some problems in the measurement of beam divergence angle for EAST neutral beam injector

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Beam angular divergence is one of the indicators to evaluate the beam quality. Operating parameters of the beam extraction system could be adjusted to gain better beam quality following the measurement results, which will be helpful not only to study the transmission characteristics of the beam and the power distribution on the heat load components, but also to understand the real-time working condition of the ion source and beam extraction system. This study includes: (1) the theoretical analysis of beam extraction pulse duration for measurement of beam angular divergence; (2) the theoretical analysis of beam intensity distribution during beam transmission for Experimental Advanced Superconducting Tokomak (EAST) neutral beam injector. Those theoretical analyses could point the way to the measurement of beam divergence angle for EAST neutral beam injector.

  17. The GlueX Start Counter and Beam Asymmetry$\\Sigma$ in Single $\\pi^{0}$ Photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Pooser, Eric [Florida Intl Univ., Miami, FL (United States)

    2016-03-26

    The GlueX experiment aims to study meson photoproduction while utilizing the coherent bremsstrahlung technique to produce a 9 GeV linearly polarized photon beam incident on a liquid H2 target. A Start Counter detector was fabricated to properly identify the accelerator electron beam buckets and to provide accurate timing information. The Start Counter detector was designed to operate at photon intensities of up to 108 γ/s in the coherent peak and provides a timing resolution ~300 ps so as to provide successful identification of the electron beam buckets to within 99% accuracy. Furthermore, the Start Counter detector provides excellent solid angle coverage, ~ 90% of 4π hermeticity, and a high degree of segmentation for background rejection. It consists of a cylindrical array of 30 scintillators with pointed ends that bend towards the beam at the downstream end. Magnetic field insensitive silicon photomultiplier detectors were selected as the readout system. An initial measurement of the beam asymmetry Sigma in the exclusive reaction γ$\\vec{p}$→ π0p, where π0 → γ has been carried out utilizing the GlueX spectrometer during the Spring 2015 commissioning run. The tagged photon energies ranged from 2.5≤ Eγ ≤ 3.0 GeV in the coherent peak. These measurements were then compared to the world data set and show remarkable agreement with only two hours of physics production running.

  18. An Ion Beam Tracking System based on a Parallel Plate Avalanche Counter

    Directory of Open Access Journals (Sweden)

    Carter I. P.

    2013-12-01

    Full Text Available A pair of twin position-sensitive parallel plate avalanche counters have been developed at the Australian National University as a tracking system to aid in the further rejection of unwanted beam particles from a 6.5 T super conducting solenoid separator named SOLEROO. Their function is to track and identify each beam particle passing through the detectors on an event-by-event basis. In-beam studies have been completed and the detectors are in successful operation, demonstrating the tracking capability. A high efficiency 512-pixelwide-angle silicon detector array will then be integrated with the tracking system for nuclear reactions studies of radioactive ions.

  19. Several atomic-physics issues connected with the use of neutral beams in fusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Post, D.E.; Grisham, L.R.; Fonck, R.J.

    1982-08-01

    Energetic neutral beams are used for heating and diagnostics in present magnetic fusion experiments. They are also being considered for use in future large experiments. Atomic physics issues are important for both the production of the neutral beams and the interaction of the beams and the plasma. Interest in neutral beams based on negative hydrogen ions is growing, largely based on advances in producing high current ion sources. An extension of the negative ion approach has been the suggestion to use negative ions of Z > 1 elements, such as carbon and oxygen, to form high power neutral beams for plasma heating.

  20. Electrostatic steering and beamlet aiming in large neutral beam injectors

    Science.gov (United States)

    Veltri, P.; Cavenago, M.; Chitarin, G.; Marcuzzi, D.; Sartori, E.; Serianni, G.; Sonato, P.

    2015-04-01

    Neutral beam injection is the main method for plasma heating in magnetic confinement fusion devices. In high energy injector (E>100 keV/amu), neutrals are obtained with reasonable efficiency by conversion of negative ions (H- or D-) via electron detachment reactions. In the case of ITER injectors, which shall operate at 1 MeV, a total ion current of ˜ 40 A is required to satisfy the heating power demand. Gridded electrodes are therefore used in the accelerator, so that 1280 negative ion beamlets are accelerated together. A carefully designed aiming system is required to control the beamlet trajectories, and to deliver their power on a focal point located several meters away from the beam source. In nowadays injectors, the aiming is typically obtained by aperture offset technique or by grid shaping. This paper discuss an alternative concept of beamlets aiming, based on an electrostatic "steerer" to be placed at the end of the accelerator. A feasibility study of this component is also presented, and its main advantages and drawbacks with respect to other methods are discussed.

  1. Electrostatic steering and beamlet aiming in large neutral beam injectors

    Energy Technology Data Exchange (ETDEWEB)

    Veltri, P., E-mail: pierluigi.veltri@igi.cnr.it; Chitarin, G.; Marcuzzi, D.; Sartori, E.; Serianni, G.; Sonato, P. [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4 - 35127 Padova (Italy); Cavenago, M. [INFN-LNL, viale dell' Università n. 2, 35020 Legnaro (Italy)

    2015-04-08

    Neutral beam injection is the main method for plasma heating in magnetic confinement fusion devices. In high energy injector (E>100 keV/amu), neutrals are obtained with reasonable efficiency by conversion of negative ions (H- or D-) via electron detachment reactions. In the case of ITER injectors, which shall operate at 1 MeV, a total ion current of ∼ 40 A is required to satisfy the heating power demand. Gridded electrodes are therefore used in the accelerator, so that 1280 negative ion beamlets are accelerated together. A carefully designed aiming system is required to control the beamlet trajectories, and to deliver their power on a focal point located several meters away from the beam source. In nowadays injectors, the aiming is typically obtained by aperture offset technique or by grid shaping. This paper discuss an alternative concept of beamlets aiming, based on an electrostatic ”steerer” to be placed at the end of the accelerator. A feasibility study of this component is also presented, and its main advantages and drawbacks with respect to other methods are discussed.

  2. Condition monitoring for a neutral beam injector cryopumping system

    Energy Technology Data Exchange (ETDEWEB)

    Wright, N., E-mail: n.wright@lboro.ac.uk [School of Electronic and Electrical Engineering, Loughborough University, Loughborough LE11 3TU (United Kingdom); Dixon, R., E-mail: r.dixon@lboro.ac.uk [School of Electronic and Electrical Engineering, Loughborough University, Loughborough LE11 3TU (United Kingdom); Verhoeven, R., E-mail: roel.verhoeven@ccfe.ac.uk [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2013-10-15

    Highlights: ► The development of a cryopumping condition monitoring scheme is presented. ► A residual generation scheme is used to detect two faults. ► Kalman filtering is used to generate the residuals. ► A filtering and voting arrangement is used to evaluate the residuals. ► A non-linear simulation model is used to verify the scheme. -- Abstract: For neutral beam injection systems, the maintenance of a vacuum inside the injector box is essential for normal operation. Cryogenic pumping systems are often used to create and maintain this vacuum. Cryogenic pumping systems have been deployed on the neutral beam heating systems supporting the Joint European Torus. With these as a target application, the development of a condition monitoring scheme is presented. The scheme uses a residual generation approach. A bank of Kalman filters is used to estimate measured process variables. A residual evaluator is used to map residual signals onto a set of faults. Two example faults are simulated to demonstrate the response of the scheme. This paper contributes to the wider fusion development programme by demonstrating how a contemporary condition monitoring technique can be applied to a fusion support system, in order to improve its availability.

  3. Performance of the KTeV high-energy neutral kaon beam at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Bocean, V.

    1998-06-01

    The performance of the primary and secondary beams for the KTeV experiments E832 and E799-II is reviewed. The beam was commissioned in the summer of 1996 and initially operated for approximately one year. The report includes results on the primary beam, target station including primary beam dump and muon sweeping system, neutral beam collimation system, and alignment.

  4. Fast-ion transport and neutral beam current drive in ASDEX upgrade

    DEFF Research Database (Denmark)

    Geiger, B.; Weiland, M.; Jacobsen, Asger Schou

    2015-01-01

    The neutral beam current drive efficiency has been investigated in the ASDEX Upgrade tokamak by replacing on-axis neutral beams with tangential off-axis beams. A clear modification of the radial fast-ion profiles is observed with a fast-ion D-alpha diagnostic that measures centrally peaked profil...

  5. Scheme for Low Energy Beam Transport with a Non-Neutralized Section

    Energy Technology Data Exchange (ETDEWEB)

    Shemyakin, A. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Prost, L. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-04-23

    A typical Low Energy Beam Transport (LEBT) design relies on dynamics with nearly complete beam space charge neutralization over the entire length of the LEBT. This paper argues that, for a beam with modest perveance and uniform current density distribution when generated at the source, a downstream portion of the LEBT can be un-neutralized without significant emittance growth.

  6. Maintenance schemes for the ITER neutral beam test facility

    Energy Technology Data Exchange (ETDEWEB)

    Zaccaria, P. [Consorzio RFX, Association EURATOM-ENEA, I-35127 Padova (Italy)]. E-mail: pierluigi.zaccaria@igi.cnr.it; Dal Bello, S. [Consorzio RFX, Association EURATOM-ENEA, I-35127 Padova (Italy); Marcuzzi, D. [Consorzio RFX, Association EURATOM-ENEA, I-35127 Padova (Italy); Masiello, A. [Consorzio RFX, Association EURATOM-ENEA, I-35127 Padova (Italy); Cordier, J.J. [Association EURATOM-CEA, DSM/Departement Recherche Fusion Controlee, CEA/Cadarache, F-13108 Saint Paul Lez Durance Cedex (France); Hemsworth, R. [Association EURATOM-CEA, DSM/Departement Recherche Fusion Controlee, CEA/Cadarache, F-13108 Saint Paul Lez Durance Cedex (France); Antipenkov, A. [Forschungszentrum Karlsruhe, Institut fuer Technische Physik, 76021 Karlsruhe (Germany); Day, C. [Forschungszentrum Karlsruhe, Institut fuer Technische Physik, 76021 Karlsruhe (Germany); Dremel, M. [Forschungszentrum Karlsruhe, Institut fuer Technische Physik, 76021 Karlsruhe (Germany); Mack, A. [Forschungszentrum Karlsruhe, Institut fuer Technische Physik, 76021 Karlsruhe (Germany); Jones, T. [UKAEA Culham EURATOM/UKAEA Fusion Association Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Coniglio, A. [Consorzio RFX, Association EURATOM-ENEA, I-35127 Padova (Italy); Pillon, M. [ENEA, Centro Ricerche Frascati, I-00044 Frascati, Rome (Italy); Sandri, S. [ENEA, Centro Ricerche Frascati, I-00044 Frascati, Rome (Italy); Speth, E. [IPP CSU-Max-Planck-Institut fuer Plasma Physik, D-85748 Garching (Germany); Tanga, A. [IPP CSU-Max-Planck-Institut fuer Plasma Physik, D-85748 Garching (Germany); Antoni, V. [Consorzio RFX, Association EURATOM-ENEA, I-35127 Padova (Italy); Pietro, E. Di [EFDA CSU, D-85748 Garching (Germany); Mondino, P.L. [EFDA CSU, D-85748 Garching (Germany)

    2005-11-15

    The ITER neutral beam test facility (NBTF) is planned to be built, after the approval of the ITER construction and the choice of the ITER site, with the agreement of the ITER international team and of the JA and RF participant teams. The key purpose is to progressively increase the performance of the first ITER injector and to demonstrate its reliability at the maximum operation parameters: power delivered to the plasma 16.5 MW, beam energy 1 MeV, accelerated D{sup -} ion current 40 A, pulse length 3600 s. Several interventions for possible modifications and for maintenance are expected during the early operation of the ITER injector in order to optimise the beam generation, aiming and steering. The maintenance scheme and the related design solutions are therefore a very important aspect to be considered for the NBTF design. The paper describes consistently the many interrelated aspects of the design, such as the optimisation of the vessel and cryopump geometry, in order to get a better maintenance flexibility, an easier man access and a larger access for diagnostic and monitoring.

  7. Maintenance schemes for the ITER neutral beam test facility

    Energy Technology Data Exchange (ETDEWEB)

    Zaccaria, P.; Dal Bello, S.; Marcuzzi, D.; Masiello, A.; Coniglio, A.; Antoni, V. [Consorzio RFX Association Euratom-ENEA, Padova (Italy); Cordier, J.J.; Hemsworth, R. [Association Euratom-CEA Cadarache (DSM/DRFC), 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Antipenkov, A.; Day, C.; Dremel, M.; Mack, A. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Technische Physik; Pillon, M.; Sandri, S. [ENEA, Frascati (Italy). Centro Ricerche Energia; Speth, E.; Tanga, A. [Max-Planck-Institut fuer Plasmaphysik, IPP CSU, Garching (Germany); Jones, T. [UKAEA Culham Euratom/Ukaea Fusion Association Culham Science Centre, Abingdom OX (United Kingdom); Di Pietro, E.; Mondino, P.L. [EFDA CSU, Garching (Germany)

    2004-07-01

    The ITER neutral beam test facility (NBTF) is planned to be built, after the approval of the ITER construction and the choice of the ITER site, with the agreement of the ITER International Team and of the JA and RF participant teams. The key purpose is to progressively increase the performance of the first ITER injector and to demonstrate its reliability at the maximum operation parameters: power delivered to the plasma 16.5 MW, beam energy 1 MeV, accelerated D{sup -} ion current 40 A, pulse length 3600 s. Several interventions for possible modifications and for maintenance are expected during the early operation of the ITER injector in order to optimize the beam generation, aiming and steering. The maintenance scheme and the related design solutions are therefore a very important aspect to be considered for the NBTF design. The paper describes consistently the many interrelated aspects of the design, such as the optimisation of the vessel and cryopump geometry, in order to get a better maintenance flexibility, an easier man access and a larger access for diagnostic and monitoring. (authors)

  8. Thermal effects in high power cavities for photoneutralization of D- beams in future neutral beam injectors

    Science.gov (United States)

    Fiorucci, Donatella; Feng, Jiatai; Pichot, Mikhaël; Chaibi, Walid

    2015-04-01

    Photoneutralization may represent a key issue in the neutral beam injectors for future fusion reactors. In fact, photodetachment based neutralization combined with an energy recovery system increase the injector overall efficiency up to 60%. This is the SIPHORE injector concept in which photoneutralization is realized in a refolded cavity [1]. However, about 1 W of the several megaWatts intracavity power is absorbed by the mirrors coatings and gives rise to important thermoelastic distortions. This is expected to change the optical behavior of the mirrors and reduce the enhancement factor of the cavity. In this paper, we estimate these effects and we propose a thermal system to compensate it.

  9. Comparison of experimental data and 3D simulations of ion beam neutralization from the neutralized transport experiment

    Energy Technology Data Exchange (ETDEWEB)

    Thoma, C.; Welch, D.R.; Yu, S.S.; Henestroza, E.; Roy, P.K.; Eylon, S.; Gilson, E.P.

    2004-09-22

    The Neutralized Transport Experiment (NTX) at Lawrence Berkeley National Laboratory has been designed to study the final focus and neutralization of high perveance ion beams for applications in heavy ion fusion (HIF) and high energy density physics (HEDP) experiments. Pre-formed plasmas in the last meter before the target of the scaled experiment provide a source of electrons which neutralize the ion current and prevent the space-charge induced spreading of the beam spot. NTX physics issues are discussed and experimental data is analyzed and compared with 3D particle-in-cell simulations. Along with detailed target images, 4D phase-space data of the NTX at the entrance of the neutralization region has been acquired. This data is used to provide a more accurate beam distribution with which to initialize the simulation. Previous treatments have used various idealized beam distributions which lack the detailed features of the experimental ion beam images. Simulation results are compared with NTX experimental measurements for 250 keV K{sup +} ion beams with dimensionless perveance of 1-7 x 10{sup -4}. In both simulation and experiment, the deduced beam charge neutralization is close to the predicted maximum value.

  10. Requirements specification for the Neutral Beam Injector on FAST

    Energy Technology Data Exchange (ETDEWEB)

    Baruzzo, M., E-mail: matteo.baruzzo@igi.cnr.it [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti 4, 35127 Padova (Italy); Bolzonella, T. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti 4, 35127 Padova (Italy); Calabro, G.; Crisanti, F.; Cucchiaro, A. [Associazione Euratom/ENEA sulla Fusione, CP 65-00044 Frascati, Rome (Italy); Marcuzzi, D.; Rigato, W. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti 4, 35127 Padova (Italy); Schneider, M. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Sonato, P.; Valisa, M.; Zaccaria, P. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti 4, 35127 Padova (Italy); Artaud, J.F.; Basiuk, V. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Cardinali, A. [Associazione Euratom/ENEA sulla Fusione, CP 65-00044 Frascati, Rome (Italy); Imbeaux, F. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Lauro Taroni, L. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti 4, 35127 Padova (Italy); Marinucci, M. [Associazione Euratom/ENEA sulla Fusione, CP 65-00044 Frascati, Rome (Italy); Mantica, P. [Istituto di Fisica del Plasma ' P.Caldirola' , Associazione Euratom-ENEA-CNR, Milano (Italy); Zonca, F. [Associazione Euratom/ENEA sulla Fusione, CP 65-00044 Frascati, Rome (Italy)

    2011-10-15

    This paper discusses the scientific and technical requirements for a Neutral Beam Injection system on the FAST tokamak and describes a preliminary conceptual design of a suitable injector. FAST is being proposed as a European experiment in support to the operations on ITER and to the design of DEMO. The specific mission of this device is an integrated approach to a number of outstanding burning plasmas physics and operational issues with an emphasis on the impact of fast particles on turbulent transport. Such scientific requirements set a series of technical challenges regarding the injector and the coupling of the injector to the FAST main chamber that are addressed in the paper. A preliminary conceptual design of the injector is proposed which attempts to meet the stated requirements.

  11. Measurement of Inclusive Neutral Current Neutral Pion Production on Carbon in a Few-GeV Neutrino Beam

    CERN Document Server

    Kurimoto, Y

    2009-01-01

    The SciBooNE Collaboration reports inclusive neutral current neutral pion production by a muon neutrino beam on a polystyrene target (C8H8). We obtain (7.7 \\pm 0.5(stat.) \\pm 0.5 (sys.)) x 10^(-2) as the ratio of the neutral current neutral pion production to total charged current cross section; the mean energy of neutrinos producing detected neutral pions is 1.1 GeV. The result agrees with the Rein-Sehgal model implemented in our neutrino interaction simulation program with nuclear effects. The spectrum shape of the neutral pion momentum and angle agree with the model. We also measure the ratio of the neutral current coherent pion production to total charged current cross section to be (0.9 \\pm 0.5) x 10^(-2).

  12. Measurement of neutral current coherent neutral pion production on carbon in a few-GeV neutrino beam

    CERN Document Server

    Kurimoto, Y; Brice, S J; Bugel, L; Catala-Perez, J; Cheng, G; Conrad, J M; Djurcic, Z; Dore, U; Finley, D A; Franke, A J; Giganti, C; Gomez-Cadenas, J J; Guzowski, P; Hanson, A; Hayato, Y; Hiraide, K; Jover-Manas, G; Karagiorgi, G; Katori, T; Kobayashi, Y K; Kobilarcik, T; Kubo, H; Louis, W C; Loverre, P F; Ludovici, L; Mahn, K B M; Mariani, C; Masuike, S; Matsuoka, K; McGary, V T; Metcalf, W; Mills, G B; Mitsuka, G; Miyachi, Y; Mizugashira, S; Moore, C D; Nakajima, Y; Nakaya, T; Napora, R; Nienaber, P; Orme, D; Otani, M; Russell, A D; Sanchez, F; Shaevitz, M H; Shibata, T -A; Sorel, M; Stefanski, R J; Takei, H; Tanaka, H -K; Tanaka, M; Tayloe, R; Taylor, I J; Tesarek, R J; Uchida, Y; Van de Water, R; Walding, J J; Wascko, M O; White, H B; Wilking, M J; Yokoyama, M; Zeller, G P; Zimmerman, E D

    2010-01-01

    The SciBooNE Collaboration reports a measurement of neutral current coherent neutral pion production on carbon by a muon neutrino beam with average energy 0.8 GeV. The separation of coherent from inclusive neutral pion production has been improved by detecting recoil protons from resonant neutral pion production. We measure the ratio of the neutral current coherent neutral pion production to total charged current cross sections to be (1.16 +/- 0.24) x 10-2. The ratio of charged current coherent pion to neutral current coherent pion production is calculated to be 0.14+0.30 -0.28, using our published charged current coherent pion measurement.

  13. Measurement of neutral current neutral pion production on Carbon in a Few-GeV Neutrino Beam

    CERN Document Server

    Kurimoto, Y

    2009-01-01

    The SciBooNE Collaboration has measured neutral current neutral pion production by the muon neutrino beam at a polystyrene target (C8H8). We obtained (7.7+- 0.5(stat.)+0.4-0.5 (sys.)) x 10^-2 as cross section ratio of the neutral current neutral pion production to total charged current cross section at the mean neutrino energy of 1.16 GeV. This result is consistent with the Monte Carlo prediction based on the Rein-Sehgal model

  14. Demonstration of counter beam fast heating scheme by using a spherical CD shell target

    Science.gov (United States)

    Mori, Y.; Nishimura, Y.; Hanayama, R.; Nakayama, S.; Ishii, K.; Kitagawa, Y.; Sekine, T.; Takeuchi, Y.; Kurita, T.; Kato, Y.; Sato, N.; Kurita, N.; Kawashima, T.; Hioki, T.; Motohiro, T.; Sunahara, A.; Sentoku, Y.; Miura, E.; Iwamoto, A.; Sakagami, H.

    2016-10-01

    We report fast heating of a shock-imploded core under counter beam configuration that published in recent. Experiments are performed by using a repetitive IFE driver HAMA. Experiments results show that (i) a shock-imploded core with 70 micron diameter, originally deuterated polystyrene (CD) spherical shell of 500 micron diameter, is flashed by counter irradiating 110 fs, 7 TW laser pulses. The coupling efficiency from the laser to the core emission was inferred 13%. A collisional Particle-In-Cell simulation code PICLS2D indicates a possibility that counter hot electron currents generate magnetic filaments in the imploded core. (ii) Fast electrons with energy bellow a few MeV might be trapped by these filaments in the core region supposed to be contributing to the observed X-ray flash and the high coupling efficiency. These results indicate a possibility that counter irradiating fast heating scheme can improve the energy coupling into the core by hot electrons those are limited to less 10% for one-side irradiation fast heating conducted so far.

  15. Maximum entropy algorithm and its implementation for the neutral beam profile measurement

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Wook; Cho, Gyu Seong [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Cho, Yong Sub [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    A tomography algorithm to maximize the entropy of image using Lagrangian multiplier technique and conjugate gradient method has been designed for the measurement of 2D spatial distribution of intense neutral beams of KSTAR NBI (Korea Superconducting Tokamak Advanced Research Neutral Beam Injector), which is now being designed. A possible detection system was assumed and a numerical simulation has been implemented to test the reconstruction quality of given beam profiles. This algorithm has the good applicability for sparse projection data and thus, can be used for the neutral beam tomography. 8 refs., 3 figs. (Author)

  16. Recent improvements to the ITER neutral beam system design

    Energy Technology Data Exchange (ETDEWEB)

    Grisham, L.R., E-mail: lgrisham@pppl.gov [Princeton University, Plasma Physics Laboratory, P.O. Box 451, Princeton, NJ 08543 (United States); Agostinetti, P. [Consorzio RFX, Euratom-ENEA Association, C.so Stati Uniti 4, I-35127 Padova (Italy); Barrera, G. [EURATOM-CIEMAT Association, Avda. Complutense 40, 28040 Madrid (Spain); Blatchford, P. [Culham Center for Fusion Energy, Abingdon, Oxon. OX14 3DB (United Kingdom); Boilson, D.; Chareyre, J. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Chitarin, G. [Consorzio RFX, Euratom-ENEA Association, C.so Stati Uniti 4, I-35127 Padova (Italy); Esch, H.P.L. de [CEA-Cadarache, IRFM, F-13108 Saint-Paul-lez-Durance (France); De Lorenzi, A. [Consorzio RFX, Euratom-ENEA Association, C.so Stati Uniti 4, I-35127 Padova (Italy); Franzen, P.; Fantz, U. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany); Gagliardi, M. [Culham Center for Fusion Energy, Abingdon, Oxon. OX14 3DB (United Kingdom); Hemsworth, R.S. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Kashiwagi, M. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); King, D. [Culham Center for Fusion Energy, Abingdon, Oxon. OX14 3DB (United Kingdom); Krylov, A. [Russian Research Centre, Kurchatov Institute, Moscow (Russian Federation); Kuriyama, M. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Marconato, N.; Marcuzzi, D. [Consorzio RFX, Euratom-ENEA Association, C.so Stati Uniti 4, I-35127 Padova (Italy); Roccella, M. [L.T. Calcoli SaS, Via C. Baslini 13, 23807 Merate (Italy); and others

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Improvements to ITER accelerator voltage holding. Black-Right-Pointing-Pointer Improvements to ITER negative ion source design. Black-Right-Pointing-Pointer Improvements to ITER megavolt bushing. Black-Right-Pointing-Pointer Improvements to beamline components. Black-Right-Pointing-Pointer Accelerator design improvements. - Abstract: The ITER [1] fusion device is expected to demonstrate the feasibility of magnetically confined deuterium-tritium plasma as an energy source which might one day lead to practical power plants. Injection of energetic beams of neutral atoms (up to 1 MeV D{sup 0} or up to 870 keV H{sup 0}) will be one of the primary methods used for heating the plasma, and for driving toroidal electrical current within it, the latter being essential in producing the required magnetic confinement field configuration. The design calls for each beamline to inject up to 16.5 MW of power through the duct into the tokamak, with an initial complement of two beamlines injecting parallel to the direction of the current arising from the tokamak transformer effect, and with the possibility of eventually adding a third beamline, also in the co-current direction. The general design of the beamlines has taken shape over the past 17 years [2], and is now predicated upon an RF-driven negative ion source based upon the line of sources developed by the Institute for Plasma Physics (IPP) at Garching during recent decades [3-5], and a multiple-aperture multiple-grid electrostatic accelerator derived from negative ion accelerators developed by the Japan Atomic Energy Agency (JAEA) across a similar span of time [6-8]. During the past years, the basic concept of the beam system has been further refined and developed, and assessment of suitable fabrication techniques has begun. While many design details which will be important to the installation and implementation of the ITER beams have been worked out during this time, this paper focuses

  17. The potential role of Neutral Beam Injection in EU DEMO

    Science.gov (United States)

    Vincenzi, Pietro; Artaud, Jean-Francois; Bolzonella, Tommaso; Giruzzi, Gerardo

    2016-10-01

    EU DEMO studies for pulsed (DEMO1) and steady-state (DEMO2) concepts are currently in the pre-conceptual phase. Present DEMO1 design is based on ITER baseline H-mode scenario, while DEMO2 is based on advanced scenarios with moderate reversed q profile sustained by non-inductive currents. One of the possible flattop heating power systems currently considered is Neutral Beam Injection (NBI). In this work the role of NBI in DEMO1 and DEMO2 is investigated by means of integrated simulations of DEMO scenarios using METIS fast tokamak modelling tool. Limitations, requirements and benefits of the use of a NBI system are discussed. For DEMO1 pulsed concept, the role of NBI is mainly central plasma heating for scenario stability (high fusion power H-mode). As a by-product of the tangential injection, NBI is capable of current drive, which is favorable in order to extend the discharge duration. Regarding a steady-state DEMO2 concept, in addition to plasma heating, NBI becomes a direct actuator for the advanced scenario by driving a considerable part of the plasma current. This requires more than 100MW with off-axis injection. The effect of an increase of the injection energy on the driven current density profile is also presented for DEMO2.

  18. Conceptual design of the beam source for the DEMO Neutral Beam Injectors

    Science.gov (United States)

    Sonato, P.; Agostinetti, P.; Fantz, U.; Franke, T.; Furno, I.; Simonin, A.; Tran, M. Q.

    2016-12-01

    DEMO (DEMOnstration Fusion Power Plant) is a proposed nuclear fusion power plant that is intended to follow the ITER experimental reactor. The main goal of DEMO will be to demonstrate the possibility to produce electric energy from the fusion reaction. The injection of high energy neutral beams is one of the main tools to heat the plasma up to fusion conditions. A conceptual design of the Neutral Beam Injector (NBI) for the DEMO fusion reactor, is currently being developed by Consorzio RFX in collaboration with other European research institutes. High efficiency and low recirculating power, which are fundamental requirements for the success of DEMO, have been taken into special consideration for the DEMO NBI. Moreover, particular attention has been paid to the issues related to reliability, availability, maintainability and inspectability. A conceptual design of the beam source for the DEMO NBI is here presented featuring 20 sub-sources (two adjacent columns of 10 sub-sources each), following a modular design concept, with each sub-source featuring its radio frequency driver, capable of increasing the reliability and availability of the DEMO NBI. Copper grids with increasing size of the apertures have been adopted in the accelerator, with three main layouts of the apertures (circular apertures, slotted apertures and frame-like apertures for each sub-source). This design, permitting to significantly decrease the stripping losses in the accelerator without spoiling the beam optics, has been investigated with a self-consistent model able to study at the same time the magnetic field, the electrostatic field and the trajectory of the negative ions. Moreover, the status on the R&D carried out in Europe on the ion sources is presented.

  19. A simple counter-flow cooling system for a supersonic free-jet beam source assembly.

    Science.gov (United States)

    Barr, M; Fahy, A; Martens, J; Dastoor, P C

    2016-05-01

    A simple design for an inexpensive, cooled, free-jet beam source is described. The source assembly features an integrated cooling system as supplied by a counter-flow of chilled nitrogen, and is composed primarily of off-the-shelf tube fittings. The design facilitates rapid implementation and eases subsequent alignment with respect to any downstream beamline aperture. The source assembly outlined cools the full length of the stagnation volume, offering temperature control down to 100 K and long-term temperature stability better than ±1 K.

  20. A simple counter-flow cooling system for a supersonic free-jet beam source assembly

    Energy Technology Data Exchange (ETDEWEB)

    Barr, M.; Fahy, A.; Martens, J.; Dastoor, P. C., E-mail: Paul.Dastoor@newcastle.edu.au [Centre for Organic Electronics, University of Newcastle, Callaghan, NSW 2308 (Australia)

    2016-05-15

    A simple design for an inexpensive, cooled, free-jet beam source is described. The source assembly features an integrated cooling system as supplied by a counter-flow of chilled nitrogen, and is composed primarily of off-the-shelf tube fittings. The design facilitates rapid implementation and eases subsequent alignment with respect to any downstream beamline aperture. The source assembly outlined cools the full length of the stagnation volume, offering temperature control down to 100 K and long-term temperature stability better than ±1 K.

  1. Initial Results on Neutralized Drift Compression Experiments (NDCX-IA) for High Intensity Ion Beam

    CERN Document Server

    Roy, Prabir K; Baca, David; Bieniosek, Frank; Coleman, Joshua E; Davidson, Ronald C; Efthimion, Philip; Eylon, Shmuel; Gilson, Erik P; Grant Logan, B; Greenway, Wayne; Henestroza, Enrique; Kaganovich, Igor D; Leitner, Matthaeus; Rose, David; Sefkow, Adam; Sharp, William M; Shuman, Derek; Thoma, Carsten H; Vanecek, David; Waldron, William; Welch, Dale; Yu, Simon

    2005-01-01

    Ion beam neutralization and compression experiments are designed to determine the feasibility of using compressed high intensity ion beams for high energy density physics (HEDP) experiments and for inertial fusion power. To quantitatively ascertain the various mechanisms and methods for beam compression, the Neutralized Drift Compression Experiment (NDCX) facility is being constructed at Lawrence Berkeley National Laboratory (LBNL). In the first compression experiment, a 260 KeV, 25 mA, K+ ion beam of centimeters size is radially compressed to a mm size spot by neutralization in a meter-long plasma column and beam peak current is longitudinally compressed by an induction velocity tilt core. Instrumentation, preliminary results of the experiments, and practical limits of compression are presented. These include parameters such as emittance, degree of neutralization, velocity tilt time profile, and accuracy of measurements (fast and spatially high resolution diagnostic) are discussed.

  2. The design and construction of the beam scintillation counter for CMS

    CERN Document Server

    Bell, Alan James

    2008-01-01

    This thesis presents the design qualification and construction of the Beam Scintillator Counter (BSC) for the CMS Collaboration at CERN in 2007 - 2008. The BSC detector is designed to aid in the commissioning of the Compact Muon Solenoid (CMS) during the first 2 years of operation and provide technical triggering for beam halo and minimum-bias events. Using plastic scintillator tiles mounted at both ends of CMS, it will detect minimum ionizing particles through the low-to-mid luminosity phases of the Large Hadron Collider (LHC) commissioning. During these early phases, the BSC will provide probably the most interesting and widely used data of any of the CMS sub-detectors and will be employed in the track based alignment procedure of the central tracker and commissioning of the Forward Hadron Calorimeter.

  3. Beyond ITER: neutral beams for a demonstration fusion reactor (DEMO) (invited).

    Science.gov (United States)

    McAdams, R

    2014-02-01

    In the development of magnetically confined fusion as an economically sustainable power source, International Tokamak Experimental Reactor (ITER) is currently under construction. Beyond ITER is the demonstration fusion reactor (DEMO) programme in which the physics and engineering aspects of a future fusion power plant will be demonstrated. DEMO will produce net electrical power. The DEMO programme will be outlined and the role of neutral beams for heating and current drive will be described. In particular, the importance of the efficiency of neutral beam systems in terms of injected neutral beam power compared to wallplug power will be discussed. Options for improving this efficiency including advanced neutralisers and energy recovery are discussed.

  4. Beyond ITER: Neutral beams for a demonstration fusion reactor (DEMO) (invited)

    Energy Technology Data Exchange (ETDEWEB)

    McAdams, R., E-mail: roy.mcadams@ccfe.ac.uk [EURATOM/CCFE Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom)

    2014-02-15

    In the development of magnetically confined fusion as an economically sustainable power source, International Tokamak Experimental Reactor (ITER) is currently under construction. Beyond ITER is the demonstration fusion reactor (DEMO) programme in which the physics and engineering aspects of a future fusion power plant will be demonstrated. DEMO will produce net electrical power. The DEMO programme will be outlined and the role of neutral beams for heating and current drive will be described. In particular, the importance of the efficiency of neutral beam systems in terms of injected neutral beam power compared to wallplug power will be discussed. Options for improving this efficiency including advanced neutralisers and energy recovery are discussed.

  5. Optimization of a constrained linear monochromator design for neutral atom beams.

    Science.gov (United States)

    Kaltenbacher, Thomas

    2016-04-01

    A focused ground state, neutral atom beam, exploiting its de Broglie wavelength by means of atom optics, is used for neutral atom microscopy imaging. Employing Fresnel zone plates as a lens for these beams is a well established microscopy technique. To date, even for favorable beam source conditions a minimal focus spot size of slightly below 1μm was reached. This limitation is essentially given by the intrinsic spectral purity of the beam in combination with the chromatic aberration of the diffraction based zone plate. Therefore, it is important to enhance the monochromaticity of the beam, enabling a higher spatial resolution, preferably below 100nm. We propose to increase the monochromaticity of a neutral atom beam by means of a so-called linear monochromator set-up - a Fresnel zone plate in combination with a pinhole aperture - in order to gain more than one order of magnitude in spatial resolution. This configuration is known in X-ray microscopy and has proven to be useful, but has not been applied to neutral atom beams. The main result of this work is optimal design parameters based on models for this linear monochromator set-up followed by a second zone plate for focusing. The optimization was performed for minimizing the focal spot size and maximizing the centre line intensity at the detector position for an atom beam simultaneously. The results presented in this work are for, but not limited to, a neutral helium atom beam.

  6. Calculation of prompt loss and toroidal field ripple loss under neutral beam injection on EAST

    Science.gov (United States)

    Wu, Bin; Hao, Baolong; White, Roscoe; Wang, Jinfang; Zang, Qing; Han, Xiaofeng; Hu, Chundong

    2017-02-01

    Neutral beam injection is a major auxiliary heating method in the EAST experimental campaign. This paper gives detailed calculations of beam loss with different plasma equilibria using the guiding center code ORBIT and NUBEAM/TRANSP. Increasing plasma current can dramatically lower the beam ion prompt loss and ripple loss. Countercurrent beam injection gives a much larger prompt loss fraction than co-injection, and ripple-induced collisionless stochastic diffusion is the dominant loss channel.

  7. Precision measurement of thermal neutron beam densities using a 3He proportional counter

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage; Bahnsen, A.; Brown, W.K.

    1967-01-01

    A new method, based on the 3He(n, p)T reaction, has been developed for the accurate determination of thermal neutron beam densities. Several comparisons were made with the conventional Au-foil activation method, and agreement was obtained between the two methods within an experimental uncertainty...... of ±0.4%. Fundamental advantages of the method include the 1ν dependence of the 3He(n, p)T cross section up to 1 keV, and the assurance of homogeneity even for very small macroscopic cross sections, because of the gaseous detector material. Although the method requires a relatively clean neutron beam......, it can be used over a wide range of neutron densities and, in particular, is capable of measuring extremely weak beams. A detector has been constructed with a well-defined efficiency and which is able to accept beams of diameters up to 10 cm. The 3He counter method is proposed as a precision standard...

  8. Energy composition of high-energy neutral beams on the COMPASS tokamak

    Directory of Open Access Journals (Sweden)

    Mitosinkova Klara

    2016-12-01

    Full Text Available The COMPASS tokamak is equipped with two identical neutral beam injectors (NBI for additional plasma heating. They provide a beam of deuterium atoms with a power of up to ~(2 × 300 kW. We show that the neutral beam is not monoenergetic but contains several energy components. An accurate knowledge of the neutral beam power in each individual energy component is essential for a detailed description of the beam- -plasma interaction and better understanding of the NBI heating processes in the COMPASS tokamak. This paper describes the determination of individual energy components in the neutral beam from intensities of the Doppler-shifted Dα lines, which are measured by a high-resolution spectrometer viewing the neutral beam-line at the exit of NBI. Furthermore, the divergence of beamlets escaping single aperture of the last accelerating grid is deduced from the width of the Doppler-shifted lines. Recently, one of the NBI systems was modified by the removal of the Faraday copper shield from the ion source. The comparison of the beam composition and the beamlet divergence before and after this modification is also presented.

  9. The ITER neutral beam test facility: Designs of the general infrastructure, cryosystem and cooling plant

    Energy Technology Data Exchange (ETDEWEB)

    Cordier, J.J. [Association EURATOM-CEA, DSM, Departement Recherche Fusion Controlee, CEA/Cadarache, bat 506, F-13108 Saint Paul Lez Durance Cedex (France)]. E-mail: jean-jacques.cordier@cea.fr; Hemsworth, R. [Association EURATOM-CEA, DSM, Departement Recherche Fusion Controlee, CEA/Cadarache, bat 506, F-13108 Saint Paul Lez Durance Cedex (France); Chantant, M. [Association EURATOM-CEA, DSM, Departement Recherche Fusion Controlee, CEA/Cadarache, bat 506, F-13108 Saint Paul Lez Durance Cedex (France); Gravil, B. [Association EURATOM-CEA, DSM, Departement Recherche Fusion Controlee, CEA/Cadarache, bat 506, F-13108 Saint Paul Lez Durance Cedex (France); Henry, D. [Association EURATOM-CEA, DSM, Departement Recherche Fusion Controlee, CEA/Cadarache, bat 506, F-13108 Saint Paul Lez Durance Cedex (France); Sabathier, F. [Association EURATOM-CEA, DSM, Departement Recherche Fusion Controlee, CEA/Cadarache, bat 506, F-13108 Saint Paul Lez Durance Cedex (France); Doceul, L. [Association EURATOM-CEA, DSM, Departement Recherche Fusion Controlee, CEA/Cadarache, bat 506, F-13108 Saint Paul Lez Durance Cedex (France); Thomas, E. [Association EURATOM-CEA, DSM, Departement Recherche Fusion Controlee, CEA/Cadarache, bat 506, F-13108 Saint Paul Lez Durance Cedex (France); Houtte, D. van [Association EURATOM-CEA, DSM, Departement Recherche Fusion Controlee, CEA/Cadarache, bat 506, F-13108 Saint Paul Lez Durance Cedex (France); Zaccaria, P. [CONSORZIO RFX Association EURATOM-ENEA, Corso Stati Uniti 4, I-35127 Padova (Italy); Antoni, V. [CONSORZIO RFX Association EURATOM-ENEA, Corso Stati Uniti 4, I-35127 Padova (Italy); Bello, S. Dal; Marcuzzi, D. [CONSORZIO RFX Association EURATOM-ENEA, Corso Stati Uniti 4, I-35127 Padova (Italy); Antipenkov, A.; Day, C.; Dremel, M. [FZK, Institut fuer Technische Physik, Karlsruhe 76021 (Germany); Mondino, P.L. [EFDA CSU, Max-Planck-Institut fuer Plasma Physik Boltzmannstr. 2, D-85748 Garching (Germany)

    2005-11-15

    The CEA Association is involved, in close collaboration with ENEA, FZK, IPP and UKAEA European Associations, in the first ITER neutral beam (NB) injector and the ITER neutral beam test facility design (EFDA task ref. TW3-THHN-IITF1). A total power of about 50 MW will have to be removed in steady state on the neutral beam test facility (NBTF). The main purpose of this task is to make progress with the detailed design of the first ITER NB injector and to start the conceptual design of the ITER NBTF. The general infrastructure layout of a generic site for the NBTF includes the test facility itself equipped with a dedicated beamline vessel [P.L. Zaccaria, et al., Maintenance schemes for the ITER neutral beam test facility, this conference] and integration studies of associated auxiliaries such as cooling plant, cryoplant and forepumping system.

  10. The Beam and Detector for the NA48 Neutral Kaon CP Violation Experiment at CERN

    CERN Document Server

    Fanti, V; Marras, D; Musa, L; Nappi, A; Batley, J Richard; Bevan, A; Dosanjh, R S; Galik, R; Gershon, T; Hay, B; Kalmus, George Ernest; Katvars, S; Lazzeroni, C; Moore, R; Munday, D J; Needham, M D; Olaiya, E; Parker, M A; Patel, M; Slater, M; Takach, S; White, T O; Wotton; Bal, F; Barr, G; Bocquet, G; Bremer, J; Brodier-Yourstone, P; Buchholz, P; Burns, M; Ceccucci, A; Clément, M; Cuhadar-Donzelsmann, T; Cundy, Donald C; Doble, Niels; Falaleev, V; Formenti, F; Funk, W; Gatignon, L; Gonidec, A; Grafström, P; Hallgren, B; Kapusta, P; Kesseler, G; Kubischta, Werner; Iwanski, W; Lacourt, A; Laverriere, G; Linser, G; Ljuslin, C; Marchioro, A; Mast, M; Matheys, J P; Morel, M; Norton, A; Orlic, J P; Panzer-Steindel, B; Schinzel, D; Seidl, W; Taureg, H; Tarlé, J C; Velasco, M; Vossnack, O; Wahl, H; Wertelaers, P; Weterings, J; Cheshkov, C; Gaponenko, A; Goudzovski, E; Khristov, P Z; Kalinin, A; Kekelidze, V D; Kozhevnikov, Yu; Madigozhin, D T; Molokanova, N A; Potrebenikov, Yu K; Tkatchev, A; Zinchenko, A I; Boyle, O; Knowles, I; Martin, V; Parsons, H; Peach, K J; Sacco, R; Veitch, E; Walker, A; Carassiti, V; Contalbrigo, M; Cotta-Ramusino, A; Dalpiaz, P; Damiani, C; Duclos, J; Ferretti, P; Frabetti, P L; Gianoli, A; Martini, M; Petrucci, F; Porcu, M; Rossi, F; Savrié, M; Scarpa, M; Simani, C; Bizzeti, A; Calvetti, M; Collazuol, G; Graziani, G; Iacopini, E; Lenti, M; Martelli, F; Michetti, A; Ruggiero, G; Veltri, M; Becker, H G; Behler, M; Blümer, H; Coward, D; Ebersberger, C; Eppard, K; Eppard, M; Fox, H; Geib, K H; Hirstius, A; Kalter, A; Kleinknecht, K; Koch, U; Köpke, L; Lopes da Silva, P; Luitz, S; Marouelli, P; Masetti, L; Melzer-Pellmann, I; Moosbrugger, U; Morales-Morales, C; Peters, A; Renk, B; Scheidt, J; Schmidt, J; Schmidt, S A; Schönharting, V; Schué, Yu; Staeck, J; Wanke, R; Wilhelm, R; Winhart, A; Wittgen, M; Zeitnitz, O; Dabrowski, A; Fonseca-Martin, T; Chollet, J C; Crépé, S; de La Taille, C; Fayard, L; Iconomidou-Fayard, L; Martin-Chassard, G; Ocariz, J; Unal, G; Wingerter-Seez, I; Anzivino, Giuseppina; Bordacchini, F; Cenci, P; Imbergamo, E; Lariccia, P; Lubrano, P; Mestvirishvili, A; Papi, A; Pepé, M; Piccini, M; Punturo, M; Talamonti, C; Tondini, F; Bertanza, L; Calafiura, P; Carosi, R; Casali, R; Cerri, C; Cirilli, M; Costantini, F; Fantechi, R; Fidecaro, Francesco; Fiorini, L; Giudici, S; Gorini, B; Laico, F; Lamanna, G; Mannelli, I; Marzulli, V; Passuello, D; Pierazzini, G M; Raffaelli, F; Sozzi, M; Tripiccione, R; Anvar, S; Bédérède, D; Bugeon, F; Chèze, J B; Cogan, J; De Beer, M; Debu, P; Durand, D; Edard, S; Fallou, J L; Formica, A; Gosset, L; Granier de Cassagnac, R; Heitzmann, J; Le Provost, H; Louis, F; Mandzhavidze, I; Mazzucato, E; Migliori, A; Mur, M; Peyaud, B; Schanne, S; Steinkamp, O; Tarte, Gérard; Turlay, René; Vallage, B; Holder, M; Augustin, I; Bender, M; Maier, A; Schwarz, I; Ziolkowski, M; Arcidiacono, R; Barberis, P L; Benotto, F; Bertolino, F; Biino, C; Brunasso, O; Cartiglia, N; Clemencic, M; Dattola, D; Goy-Lopez, S; Govi, G; Guida, R; Marchetto, F; Menichetti, E; Palestini, S; Pastrone, N; Chlopik, A; Guzik, Z; Nassalski, J P; Rondio, E; Szleper, M; Wislicki, W; Wronka, S; Dibon, Heinz; Fischer, G; Jeitler, Manfred; Markytan, Manfred; Mikulec, I; Neuhofer, G; Pernicka, M; Taurok, Anton; Widhalm, L

    2007-01-01

    The Beam and Detector, used for the NA48 experiment, devoted to the measurement of $Re(\\epsilon^{\\prime}/\\epsilon)$, and for the NA48/1 experiment on rare K_S and neutral hyperon decays, are described.

  11. Power supply system for KSTAR neutral beam injector

    Energy Technology Data Exchange (ETDEWEB)

    Cho, W., E-mail: franciscocho@nfri.re.kr; Bae, Y.S.; Han, W.S.; Jeong, J.H.; Kim, J.S.; Park, H.T.; Yang, H.L.; Oh, Y.K.; Kwak, J.G.

    2015-10-15

    Highlights: • The power supply system in KSTAR NBI consists of DC power supplies for ion source. • For operation NBI, DC High Voltage based on the low voltage transformer with chopper. • The surge absorber near the ion source limit the energy deposited to accelerator grid. - Abstract: The power supply system in KSTAR neutral beam injector consists of low voltage and high current DC power supplies for plasma generator of ion source and high voltage and high current DC power supply for accelerator grid system. The arc discharge is initiated by an arc power supply supplying the arc voltage between the chamber wall and 12 filaments which are heated by individual filament power supply. The negative output of arc power supply is common to each positive output of 12 filament power supplies. To interrupt the arc discharging for the fault condition of the arc current unbalance, DCCT current monitor is placed at the positive output cable of the filament power supply. The plasma grid (G1) power supply has the maximum capability of 120 kV/70 A which consists of low voltage regulator with IGBT-switched chopper array system for the voltage control in unit of 600 V and the high voltage rectified transformers to supply DC voltage of 20 kV, 30 kV, and 50 kV. The output voltage of the G1 power supply is also connected to the input of the voltage divider system which supplies the gradient voltage to the gradient grid (G2) in the range of 80–90% of G1 voltage by changing tap of winding resistors in unit of 1%. The charged G1 voltage is turned on and off by the high voltage switch (HVS) system consisting of MOSFET fast semiconductor switches which can immediately be opened less than 1 μs when the ion source grid breakdown occurs. The decelerating grid (G3) power supply is inverter system using capacitor-charge power supply to supply maximum −5 kV/5 A. The important component in power supply system is the surge absorber near the ion source to limit the arc energy deposited to

  12. Concepts for the magnetic design of the MITICA neutral beam test facility ion acceleratora)

    Science.gov (United States)

    Chitarin, G.; Agostinetti, P.; Marconato, N.; Marcuzzi, D.; Sartori, E.; Serianni, G.; Sonato, P.

    2012-02-01

    The megavolt ITER injector concept advancement neutral injector test facility will be constituted by a RF-driven negative ion source and by an electrostatic Accelerator, designed to produce a negative Ion with a specific energy up to 1 MeV. The beam is then neutralized in order to obtain a focused 17 MW neutral beam. The magnetic configuration inside the accelerator is of crucial importance for the achievement of a good beam efficiency, with the early deflection of the co-extracted and stripped electrons, and also of the required beam optic quality, with the correction of undesired ion beamlet deflections. Several alternative magnetic design concepts have been considered, comparing in detail the magnetic and beam optics simulation results, evidencing the advantages and drawbacks of each solution both from the physics and engineering point of view.

  13. Concepts for the magnetic design of the MITICA neutral beam test facility ion accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Chitarin, G. [Consorzio RFX, Corso Stati Uniti 4, 35127 Padova (Italy); Department of Engineering and Management, University of Padova, Vicenza (Italy); Agostinetti, P.; Marconato, N.; Marcuzzi, D.; Sartori, E.; Serianni, G.; Sonato, P. [Consorzio RFX, Corso Stati Uniti 4, 35127 Padova (Italy)

    2012-02-15

    The megavolt ITER injector concept advancement neutral injector test facility will be constituted by a RF-driven negative ion source and by an electrostatic Accelerator, designed to produce a negative Ion with a specific energy up to 1 MeV. The beam is then neutralized in order to obtain a focused 17 MW neutral beam. The magnetic configuration inside the accelerator is of crucial importance for the achievement of a good beam efficiency, with the early deflection of the co-extracted and stripped electrons, and also of the required beam optic quality, with the correction of undesired ion beamlet deflections. Several alternative magnetic design concepts have been considered, comparing in detail the magnetic and beam optics simulation results, evidencing the advantages and drawbacks of each solution both from the physics and engineering point of view.

  14. Concepts for the magnetic design of the MITICA neutral beam test facility ion accelerator.

    Science.gov (United States)

    Chitarin, G; Agostinetti, P; Marconato, N; Marcuzzi, D; Sartori, E; Serianni, G; Sonato, P

    2012-02-01

    The megavolt ITER injector concept advancement neutral injector test facility will be constituted by a RF-driven negative ion source and by an electrostatic Accelerator, designed to produce a negative Ion with a specific energy up to 1 MeV. The beam is then neutralized in order to obtain a focused 17 MW neutral beam. The magnetic configuration inside the accelerator is of crucial importance for the achievement of a good beam efficiency, with the early deflection of the co-extracted and stripped electrons, and also of the required beam optic quality, with the correction of undesired ion beamlet deflections. Several alternative magnetic design concepts have been considered, comparing in detail the magnetic and beam optics simulation results, evidencing the advantages and drawbacks of each solution both from the physics and engineering point of view.

  15. The design of multi-megawatt actively cooled beam dumps for the Neutral-Beam Engineering Test Facility

    Science.gov (United States)

    Paterson, J. A.; Koehler, G.; Wells, R. P.

    1981-10-01

    To test neutral beam sources up to 170 keV, 65 Amps, with 30 second beam on times, actively cooled beam dumps for both the neutral and ionized particles are required. The dumps should be able to dissipate a wide range of power density profiles by utilizing a standard modular panel design which is incorporated into a moveable support structure. The thermal hydraulic design of the panels permit the dissipation of 2 kW/sq cm anywhere on the panel surface. The water requirements of the dumps are optimized by restricting the flow to panel sections where the heat flux falls short of the design value. The mechanical design of the beam-dump structures is described along with tests performed on two different panel designs. The dissipation capabilities of the panels were tested at the critical regions to verify their use in the beam dump assemblies.

  16. Optical trapping of nanoparticles with significantly reduced laser powers by using counter-propagating beams (Presentation Recording)

    Science.gov (United States)

    Zhao, Chenglong; LeBrun, Thomas W.

    2015-08-01

    Gold nanoparticles (GNP) have wide applications ranging from nanoscale heating to cancer therapy and biological sensing. Optical trapping of GNPs as small as 18 nm has been successfully achieved with laser power as high as 855 mW, but such high powers can damage trapped particles (particularly biological systems) as well heat the fluid, thereby destabilizing the trap. In this article, we show that counter propagating beams (CPB) can successfully trap GNP with laser powers reduced by a factor of 50 compared to that with a single beam. The trapping position of a GNP inside a counter-propagating trap can be easily modulated by either changing the relative power or position of the two beams. Furthermore, we find that under our conditions while a single-beam most stably traps a single particle, the counter-propagating beam can more easily trap multiple particles. This (CPB) trap is compatible with the feedback control system we recently demonstrated to increase the trapping lifetimes of nanoparticles by more than an order of magnitude. Thus, we believe that the future development of advanced trapping techniques combining counter-propagating traps together with control systems should significantly extend the capabilities of optical manipulation of nanoparticles for prototyping and testing 3D nanodevices and bio-sensing.

  17. Performance of positive ion based high power ion source of EAST neutral beam injector

    Science.gov (United States)

    Hu, Chundong; Xie, Yahong; Xie, Yuanlai; Liu, Sheng; Xu, Yongjian; Liang, Lizhen; Jiang, Caichao; Li, Jun; Liu, Zhimin

    2016-02-01

    The positive ion based source with a hot cathode based arc chamber and a tetrode accelerator was employed for a neutral beam injector on the experimental advanced superconducting tokamak (EAST). Four ion sources were developed and each ion source has produced 4 MW @ 80 keV hydrogen beam on the test bed. 100 s long pulse operation with modulated beam has also been tested on the test bed. The accelerator was upgraded from circular shaped to diamond shaped in the latest two ion sources. In the latest campaign of EAST experiment, four ion sources injected more than 4 MW deuterium beam with beam energy of 60 keV into EAST.

  18. Efficient, radiation-hardened, 400- and 800-keV neutral-beam injection systems

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, O.A.; Cooper, W.S.; Fink, J.A.; Goldberg, D.A.; Ruby, L.; Soroka, L.; Tanabe, J.

    1983-04-01

    We present designs for two negative-ion based neutral beam lines with reactor-level power output. Both beam lines make use of such technologically advanced features as high-current-density surface-conversion ion sources, transverse-field-focussing (TFF) acceleration and transport, and laser photodetachment. For the second of these designs, we also presented detailed beam and vacuum calculations, as well as a brief description of a proof-of-principle test system currently under development.

  19. Simulation of the neutral inventory in the pilot-PSI beam

    Energy Technology Data Exchange (ETDEWEB)

    Wieggers, R.C.; Groen, P.W.C.; Blank, H.J. de; Goedheer, W.J. [FOM Institute DIFFER - Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Nieuwegein (Netherlands)

    2012-06-15

    The Eunomia code is used to study the neutral species in and near a hydrogen plasma beam. Eunomia is a non-linear Monte Carlo transport code that solves the neutral equilibrium, given a fixed background plasma. The code is developed to study the neutral inventory of Pilot-PSI and Magnum-PSI, linear devices developed to study plasma surface interactions in similar conditions as expected in the ITER divertor. Results show the influence of elastic collisions and the outer vessel wall on the neutral species. In the center of the 2 cm diameter Pilot-PSI beam the results show a strong coupling to the plasma. Only millimeters away from the center, the neutral flow, temperature and density are strongly influenced by recombination processes at the vessel wall (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Operating characteristics of a new ion source for KSTAR neutral beam injection system.

    Science.gov (United States)

    Kim, Tae-Seong; Jeong, Seung Ho; Chang, Doo-Hee; Lee, Kwang Won; In, Sang-Ryul

    2014-02-01

    A new positive ion source for the Korea Superconducting Tokamak Advanced Research neutral beam injection (KSTAR NBI-1) system was designed, fabricated, and assembled in 2011. The characteristics of the arc discharge and beam extraction were investigated using hydrogen and helium gas to find the optimum operating parameters of the arc power, filament voltage, gas pressure, extracting voltage, accelerating voltage, and decelerating voltage at the neutral beam test stand at the Korea Atomic Energy Research Institute in 2012. Based on the optimum operating condition, the new ion source was then conditioned, and performance tests were primarily finished. The accelerator system with enlarged apertures can extract a maximum 65 A ion beam with a beam energy of 100 keV. The arc efficiency and optimum beam perveance, at which the beam divergence is at a minimum, are estimated to be 1.0 A/kW and 2.5 uP, respectively. The beam extraction tests show that the design goal of delivering a 2 MW deuterium neutral beam into the KSTAR Tokamak plasma is achievable.

  1. Physics and Beam Monitoring with Forward Shower Counters (FSC) in CMS

    CERN Document Server

    Bell, Alan James; Hall-Wilton, Richard; Veres, Gabor Istvan; Khoze, Valery; Albrow, Michael; Mokhov, Nikolai; Rakhno, Igor; Brucken, Erik; Lamsa, Jerry; Lauhakangas, Rauno; Orava, Risto; Debbins, Paul; Norbeck, Edwin; Onel, Yasar; Schmidt, Ianos; Grachov, Oleg; Murray, Michael; Gronberg, Jeffrey; Hollar, Jonathan; Snow, Gregory R; Sobol, Andrei; Samoylenko, Vladimir; Penzo, Aldo

    2010-01-01

    We propose to add forward shower counters, FSC, to CMS along the beam pipes, with 59 m $\\lesssim z \\lesssim$ 140 m. These will detect showers from very forward particles with $7 \\lesssim \\eta \\lesssim 11$ interacting in the beam pipe and surrounding material. They increase the total rapidity coverage of CMS to nearly $\\Delta\\Omega = 4\\pi$, thus detecting most of the inelastic cross section $\\sigma_{inel}$, including low mass diffraction. They will help increase our understanding of all high cross section processes, which is important for understanding the ``underlying event'' backgrounds to most physics searches. To the extent that the luminosity is well known, they may (together with all of CMS) provide the best measurement of $\\sigma_{inel}$ at the LHC. They are most useful when the luminosity per bunch crossing is still low enough to provide single (no pile-up) collisions. They will allow measurements of single diffraction: $p+p\\rightarrow p \\oplus X$ (where $\\oplus$ means a rapidity gap) for lower mass...

  2. Excitation of monochromatic and stable electron acoustic wave by two counter-propagating laser beams

    Science.gov (United States)

    Xiao, C. Z.; Liu, Z. J.; Zheng, C. Y.; He, X. T.

    2017-07-01

    The undamped electron acoustic wave is a newly-observed nonlinear electrostatic plasma wave and has potential applications in ion acceleration, laser amplification and diagnostics due to its unique frequency range. We propose to make the first attempt to excite a monochromatic and stable electron acoustic wave (EAW) by two counter-propagating laser beams. The matching conditions relevant to laser frequencies, plasma density, and electron thermal velocity are derived and the harmonic effects of the EAW are excluded. Single-beam instabilities, including stimulated Raman scattering and stimulated Brillouin scattering, on the excitation process are quantified by an interaction quantity, η =γ {τ }B, where γ is the growth rate of each instability and {τ }B is the characteristic time of the undamped EAW. The smaller the interaction quantity, the more successfully the monochromatic and stable EAW can be excited. Using one-dimensional Vlasov-Maxwell simulations, we excite EAW wave trains which are amplitude tunable, have a duration of thousands of laser periods, and are monochromatic and stable, by carefully controlling the parameters under the above conditions.

  3. An alpha particle measurement system using an energetic neutral helium beam in ITER (invited).

    Science.gov (United States)

    Sasao, M; Kisaki, M; Kobuchi, T; Tsumori, K; Tanaka, N; Terai, K; Okamoto, A; Kitajima, S; Kaneko, O; Shinto, K; Wada, M

    2012-02-01

    An energetic helium neutral beam is involved in the beam neutralization measurement system of alpha particles confined in a DT fusion plasma. A full size strong-focusing He(+) ion source (2 A, the beam radius of 11.3 mm, the beam energy less than 20 keV). Present strong-focusing He(+) ion source shows an emittance diagram separated for each beamlet of multiple apertures without phase space mixing, despite the space charge of a beamlet is asymmetric and the beam flow is non-laminar. The emittance of beamlets in the peripheral region was larger than that of center. The heat load to the plasma electrode was studied to estimate the duty factor for the ITER application.

  4. Long-range attraction of an ultrarelativistic electron beam by a column of neutral plasma

    Science.gov (United States)

    Adli, E.; Lindstrøm, C. A.; Allen, J.; Clarke, C. I.; Frederico, J.; Gessner, S. J.; Green, S. Z.; Hogan, M. J.; Litos, M. D.; O'Shea, B.; Yakimenko, V.; An, W.; Clayton, C. E.; Marsh, K. A.; Mori, W. B.; Joshi, C.; Vafaei-Najafabadi, N.; Corde, S.; Lu, W.

    2016-10-01

    We report on the experimental observation of the attraction of a beam of ultrarelativistic electrons towards a column of neutral plasma. In experiments performed at the FACET test facility at SLAC we observe that an electron beam moving parallel to a neutral plasma column, at an initial distance of many plasma column radii, is attracted into the column. Once the beam enters the plasma it drives a plasma wake similar to that of an electron beam entering the plasma column head-on. A simple analytical model is developed in order to capture the essential physics of the attractive force. The attraction is further studied by 3D particle-in-cell numerical simulations. The results are an important step towards better understanding of particle beam-plasma interactions in general and plasma wakefield accelerator technology in particular.

  5. Magnetic analysis of the magnetic field reduction system of the ITER neutral beam injector

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, Germán, E-mail: german.barrera@ciemat.es [CIEMAT, Laboratorio Nacional de Fusión, Avda. Complutense 22, 28040 Madrid (Spain); Ahedo, Begoña; Alonso, Javier; Ríos, Luis [CIEMAT, Laboratorio Nacional de Fusión, Avda. Complutense 22, 28040 Madrid (Spain); Chareyre, Julien; El-Ouazzani, Anass [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Agarici, Gilbert [Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, 07/08, 08019 Barcelona (Spain)

    2015-10-15

    The neutral beam system for ITER consists of two heating and current drive neutral beam injectors (HNB) and a diagnostic neutral beam (DNB) injector. The proposed physical plant layout allows a possible third HNB injector to be installed later. For the correct operation of the beam, the ion source and the ion path until it is neutralized must operate under a very low magnetic field environment. To prevent the stray ITER field from penetrating inside those mentioned critical areas, a magnetic field reduction system (MFRS) will envelop the beam vessels and the high voltage transmission lines to ion source. This system comprises the passive magnetic shield (PMS), a box like assembly of thick low carbon steel plates, and the Active Correction and Compensation Coils (ACCC), a set of coils carrying a current which depends on the tokamak stray field. This paper describes the magnetic model and analysis results presented at the PMS and ACCC preliminary design review held in ITER organization in April 2013. The paper focuses on the magnetic model description and on the description of the analysis results. The iterative process for obtaining optimized currents in the coils is presented. The set of coils currents chosen among the many possible solutions, the magnetic field results in the interest regions and the fulfillment of the magnetic field requirements are described.

  6. In-vacuum sensors for the beamline components of the ITER neutral beam test facility

    Science.gov (United States)

    Dalla Palma, M.; Pasqualotto, R.; Sartori, E.; Spagnolo, S.; Spolaore, M.; Veltri, P.

    2016-11-01

    Embedded sensors have been designed for installation on the components of the MITICA beamline, the prototype ITER neutral beam injector (Megavolt ITER Injector and Concept Advancement), to derive characteristics of the particle beam and to monitor the component conditions during operation for protection and thermal control. Along the beamline, the components interacting with the particle beam are the neutralizer, the residual ion dump, and the calorimeter. The design and the positioning of sensors on each component have been developed considering the expected beam-surface interaction including non-ideal and off-normal conditions. The arrangement of the following instrumentation is presented: thermal sensors, strain gages, electrostatic probes including secondary emission detectors, grounding shunt for electrical currents, and accelerometers.

  7. Physics of Neutralization of Intense Charged Particle Beam Pulses by a Background Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kaganovich, I.D.; Davidson, R.C.; Dorf, M.A.; Startsev, E.A.; Sefkow, A.B; Friedman, A.F.; Lee, E.P.

    2009-09-03

    Neutralization and focusing of intense charged particle beam pulses by a background plasma forms the basis for a wide range of applications to high energy accelerators and colliders, heavy ion fusion, and astrophysics. For example, for ballistic propagation of intense ion beam pulses, background plasma can be used to effectively neutralize the beam charge and current, so that the self-electric and self-magnetic fields do not affect the ballistic propagation of the beam. From the practical perspective of designing advanced plasma sources for beam neutralization, a robust theory should be able to predict the self-electric and self-magnetic fields during beam propagation through the background plasma. The major scaling relations for the self-electric and self-magnetic fields of intense ion charge bunches propagating through background plasma have been determined taking into account the effects of transients during beam entry into the plasma, the excitation of collective plasma waves, the effects of gas ionization, finite electron temperature, and applied solenoidal and dipole magnetic fields. Accounting for plasma production by gas ionization yields a larger self-magnetic field of the ion beam compared to the case without ionization, and a wake of current density and self-magnetic field perturbations is generated behind the beam pulse. A solenoidal magnetic field can be applied for controlling the beam propagation. Making use of theoretical models and advanced numerical simulations, it is shown that even a small applied magnetic field of about 100G can strongly affect the beam neutralization. It has also been demonstrated that in the presence of an applied magnetic field the ion beam pulse can excite large-amplitude whistler waves, thereby producing a complex structure of self-electric and self-magnetic fields. The presence of an applied solenoidal magnetic field may also cause a strong enhancement of the radial self-electric field of the beam pulse propagating

  8. Physics of Neutralization of Intense High-Energy Ion Beam Pulses by Electrons

    Energy Technology Data Exchange (ETDEWEB)

    Kaganovich, I. D.; Davidson, R. C.; Dorf, M. A.; Startsev, E. A.; Sefkow, A. B.; Lee, E. P.; Friedman, A.

    2010-04-28

    Neutralization and focusing of intense charged particle beam pulses by electrons forms the basis for a wide range of applications to high energy accelerators and colliders, heavy ion fusion, and astrophysics. For example, for ballistic propagation of intense ion beam pulses, background plasma can be used to effectively neutralize the beam charge and current, so that the self-electric and self- magnetic fields do not affect the ballistic propagation of the beam. From the practical perspective of designing advanced plasma sources for beam neutralization, a robust theory should be able to predict the self-electric and self-magnetic fields during beam propagation through the background plasma. The major scaling relations for the self-electric and self-magnetic fields of intense ion charge bunches propagating through background plasma have been determined taking into account the effects of transients during beam entry into the plasma, the excitation of collective plasma waves, the effects of gas ionization, finite electron temperature, and applied solenoidal and dipole magnetic fields. Accounting for plasma production by gas ionization yields a larger self-magnetic field of the ion beam compared to the case without ionization, and a wake of current density and self-magnetic field perturbations is generated behind the beam pulse. A solenoidal magnetic field can be applied for controlling the beam propagation. Making use of theoretical models and advanced numerical simulations, it is shown that even a small applied magnetic field of about 100G can strongly affect the beam neutralization. It has also been demonstrated that in the presence of an applied magnetic field the ion beam pulse can excite large-amplitude whistler waves, thereby producing a complex structure of self-electric and self-magnetic fields. The presence of an applied solenoidal magnetic field may also cause a strong enhancement of the radial self-electric field of the beam pulse propagating through the

  9. Measurement of Neutral Current Neutral Pion Production on Carbon in a Few-GeV Neutrino Beam

    Energy Technology Data Exchange (ETDEWEB)

    Kurimoto, Yoshinori [Kyoto Univ. (Japan)

    2010-01-01

    Understanding of the π0 production via neutrino-nucleus neutral current interaction in the neutrino energy region of a few GeV is essential for the neutrino oscillation experiments. In this thesis, we present a study of neutral current π0 production from muon neutrinos scattering on a polystyrene (C8H8) target in the SciBooNE experiment. All neutrino beam data corresponding to 0.99 × 1020 protons on target have been analyzed. We have measured the cross section ratio of the neutral current π0 production to the total charge current interaction and the π0 kinematic distribution such as momentum and direction. We obtain [7.7 ± 0.5(stat.) ± 0.5(sys.)] × 10-2 as the ratio of the neutral current neutral pion production to total charged current cross section; the mean energy of neutrinos producing detected neutral pions is 1.1 GeV. The result agrees with the Rein- Sehgal model, which is generally used for the Monte Carlo simulation by many neutrino oscillation experiments. We achieve less than 10 % uncertainty which is required for the next generation search for νµ → νe oscillation. The spectrum shape of the π0 momentum and the distribution of the π0 emitted angle agree with the prediction, which means that not only the Rein-Sehgal model but also the intra-nuclear interaction models describe our data well. We also measure the ratio of the neutral current coherent pion production to total charged current cross section to be (1.17 ± 0.23 ) × 10-2 based on the Rein and Sehgal model. The result gives the evidence for non-zero coherent pion production via neutral current interaction at the mean neutrino energy of 1.0 GeV.

  10. Short-pulse, compressed ion beams at the Neutralized Drift Compression Experiment

    Science.gov (United States)

    Seidl, P. A.; Barnard, J. J.; Davidson, R. C.; Friedman, A.; Gilson, E. P.; Grote, D.; Ji, Q.; Kaganovich, I. D.; Persaud, A.; Waldron, W. L.; Schenkel, T.

    2016-05-01

    We have commenced experiments with intense short pulses of ion beams on the Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory, with 1-mm beam spot size within 2.5 ns full-width at half maximum. The ion kinetic energy is 1.2 MeV. To enable the short pulse duration and mm-scale focal spot radius, the beam is neutralized in a 1.5-meter-long drift compression section following the last accelerator cell. A short-focal-length solenoid focuses the beam in the presence of the volumetric plasma that is near the target. In the accelerator, the line-charge density increases due to the velocity ramp imparted on the beam bunch. The scientific topics to be explored are warm dense matter, the dynamics of radiation damage in materials, and intense beam and beam-plasma physics including select topics of relevance to the development of heavy-ion drivers for inertial fusion energy. Below the transition to melting, the short beam pulses offer an opportunity to study the multi-scale dynamics of radiation-induced damage in materials with pump-probe experiments, and to stabilize novel metastable phases of materials when short-pulse heating is followed by rapid quenching. First experiments used a lithium ion source; a new plasma-based helium ion source shows much greater charge delivered to the target.

  11. Short-Pulse, Compressed Ion Beams at the Neutralized Drift Compression Experiment

    CERN Document Server

    Seidl, Peter A; Davidson, Ronald C; Friedman, Alex; Gilson, Erik P; Grote, David; Ji, Qing; Kaganovich, I D; Persaud, Arun; Waldron, William L; Schenkel, Thomas

    2016-01-01

    We have commenced experiments with intense short pulses of ion beams on the Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory, with 1-mm beam spot size within 2.5 ns full-width at half maximum. The ion kinetic energy is 1.2 MeV. To enable the short pulse duration and mm-scale focal spot radius, the beam is neutralized in a 1.5-meter-long drift compression section following the last accelerator cell. A short-focal-length solenoid focuses the beam in the presence of the volumetric plasma that is near the target. In the accelerator, the line-charge density increases due to the velocity ramp imparted on the beam bunch. The scientific topics to be explored are warm dense matter, the dynamics of radiation damage in materials, and intense beam and beam-plasma physics including select topics of relevance to the development of heavy-ion drivers for inertial fusion energy. Below the transition to melting, the short beam pulses offer an opportunity to study the multi-scale dynam...

  12. Studies on space charge neutralization and emittance measurement of beam from microwave ion source

    Energy Technology Data Exchange (ETDEWEB)

    Misra, Anuraag; Goswami, A.; Sing Babu, P.; Srivastava, S.; Pandit, V. S., E-mail: pandit@vecc.gov.in, E-mail: vspandit12@gmail.com [Variable Energy Cyclotron Centre, 1-AF, Bidhannagar, Kolkata 700 064 (India)

    2015-11-15

    A 2.45 GHz microwave ion source together with a beam transport system has been developed at VECC to study the problems related with the injection of high current beam into a compact cyclotron. This paper presents the results of beam profile measurement of high current proton beam at different degrees of space charge neutralisation with the introduction of neon gas in the beam line using a fine leak valve. The beam profiles have been measured at different pressures in the beam line by capturing the residual gas fluorescence using a CCD camera. It has been found that with space charge compensation at the present current level (∼5 mA at 75 keV), it is possible to reduce the beam spot size by ∼34%. We have measured the variation of beam profile as a function of the current in the solenoid magnet under the neutralised condition and used these data to estimate the rms emittance of the beam. Simulations performed using equivalent Kapchinsky-Vladimirsky beam envelope equations with space charge neutralization factor are also presented to interpret the experimental results.

  13. Perpendicular Diffusion in the Transport of Solar Energetic Particles from Unconnected Sources: The Counter-streaming Particle Beams Revisited

    CERN Document Server

    He, H -Q

    2015-01-01

    In some solar energetic particle (SEP) events, a counter-streaming particle beam with a deep depression of flux near 90 degrees pitch angle during the beginning phase is observed. Two different interpretations exist in the community to explain this interesting phenomenon. One explanation invokes the hypothesis of an outer reflecting boundary or a magnetic mirror beyond the observer. The other one considers the effect of the perpendicular diffusion on the transport process of SEPs in the interplanetary space. In this work, we revisit the problem of the counter-streaming particle beams observed in SEP events and discuss the possible mechanisms responsible for the formation of this phenomenon. We clarify some results in previous works.

  14. Spectroscopic determination of the composition of a 50 kV hydrogen diagnostic neutral beam

    Science.gov (United States)

    Feng, X.; Nornberg, M. D.; Craig, D.; Den Hartog, D. J.; Oliva, S. P.

    2016-11-01

    A grating spectrometer with an electron multiplying charge-coupled device camera is used to diagnose a 50 kV, 5 A, 20 ms hydrogen diagnostic neutral beam. The ion source density is determined from Stark broadened Hβ emission and the spectrum of Doppler-shifted Hα emission is used to quantify the fraction of ions at full, half, and one-third beam energy under a variety of operating conditions including fueling gas pressure and arc discharge current. Beam current is optimized at low-density conditions in the ion source while the energy fractions are found to be steady over most operating conditions.

  15. Development of ion source with a washer gun for pulsed neutral beam injection.

    Science.gov (United States)

    Asai, T; Yamaguchi, N; Kajiya, H; Takahashi, T; Imanaka, H; Takase, Y; Ono, Y; Sato, K N

    2008-06-01

    A new type of economical neutral beam source has been developed by using a single washer gun, pulsed operation, and a simple electrode system. We replaced the conventional hot filaments for arc-discharge-type plasma formation with a single stainless-steel washer gun, eliminating the entire dc power supply for the filaments and the cooling system for the electrodes. Our initial experiments revealed successful beam extraction up to 10 kV and 8.6 A, based on spatial profile measurements of density and temperature in the plasma source. The system also shows the potential to control the beam profile by controlling the plasma parameters in the ion accumulation chamber.

  16. Spectroscopic determination of the composition of a 50 kV hydrogen diagnostic neutral beam

    Energy Technology Data Exchange (ETDEWEB)

    Feng, X.; Nornberg, M. D., E-mail: mdnornberg@wisc.edu; Den Hartog, D. J.; Oliva, S. P. [Department of Physics, University of Wisconsin–Madison, 1150 University Ave., Madison, Wisconsin 53706 (United States); Craig, D. [Wheaton College, Wheaton, Illinois 60187 (United States)

    2016-11-15

    A grating spectrometer with an electron multiplying charge-coupled device camera is used to diagnose a 50 kV, 5 A, 20 ms hydrogen diagnostic neutral beam. The ion source density is determined from Stark broadened H{sub β} emission and the spectrum of Doppler-shifted H{sub α} emission is used to quantify the fraction of ions at full, half, and one-third beam energy under a variety of operating conditions including fueling gas pressure and arc discharge current. Beam current is optimized at low-density conditions in the ion source while the energy fractions are found to be steady over most operating conditions.

  17. Weibel and Two-Stream Instabilities for Intense Charged Particle Beam Propagation through Neutralizing Background Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ronald C. Davidson; Igor Kaganovich; Edward A. Startsev

    2004-04-09

    Properties of the multi-species electromagnetic Weibel and electrostatic two-stream instabilities are investigated for an intense ion beam propagating through background plasma. Assuming that the background plasma electrons provide complete charge and current neutralization, detailed linear stability properties are calculated within the framework of a macroscopic cold-fluid model for a wide range of system parameters.

  18. Facility for the testing of the TFTR prototype neutral beam injector

    Energy Technology Data Exchange (ETDEWEB)

    Haughian, J.M.

    1977-07-01

    The design of the prototype neutral beam injection system for TFTR is nearing completion at the Lawrence Livermore Laboratory. This paper describes some of the features of the facility at the Lawrence Berkeley Laboratory where this prototype will be assembled and tested.

  19. Neutral V production with 14. 6 x A GeV/c silicon beams

    Energy Technology Data Exchange (ETDEWEB)

    Eiseman, S.E.; Etkin, A.; Foley, K.J.; Hackenburg, R.W.; Longacre, R.S.; Love, W.A.; Morris, T.W.; Platner, E.D.; Saulys, A.C. (Brookhaven National Lab., Upton, NY (USA)); Lindenbaum, S.J. (Brookhaven National Lab., Upton, NY (USA) City Coll., New York (USA)); Chan, C.S.; Kramer, M.A.; Zhao, K. (City Coll., New York (USA)); Hallman, T.J.; Madansky, L. (Johns Hopkins Univ., Baltimore, MD (USA)); Bonner, B.E.; Buchanan, J.A.; Chiou, C.N.; Clement, J.M.; Corcoran, M.D.; Kruk, J.W.; Mutchler, G.S.; Nessi-Tedaldi, F.; Nessi, M.; Roberts, J.B. (Rice Univ., Houston, TX (USA))

    1990-10-04

    We present the results of a measurement of neutral V production with 14.6xA GeV/c Si beams on Au and Cu targets. The {Lambda} and K{sub s}{sup 0} yields were measured as a function of negative particle multiplicity. Effective temperatures were determined from an exponential fit to the transverse mass distributions. (orig.).

  20. Initial Off-Axis Neutral Beam Checkout and Physics Experiments on DIII-D

    Science.gov (United States)

    van Zeeland, M. A.; Ferron, J. R.; Hyatt, A. W.; Murphy, C. J.; Petty, C. C.; Prater, R.; Scoville, J. T.; Heidbrink, W. W.; Muscatello, C. M.; Park, J. M.; Murakami, M.; Pace, D. C.; Holcomb, C. T.; Grierson, B. A.; Tobias, B. J.; Solomon, W. M.; Moyer, R. A.

    2011-10-01

    Two of the eight neutral beam sources on DIII-D have been modified to allow vertical steering, with the injection angle varying from horizontal to downward at an angle of 16.5 degrees for off-axis deposition. Initial experiments to assess the basic beam functionality, geometry, and confinement were carried out. Dα images of beam into gas and plasma yield beam neutral profiles and are key in assessing beam shape and clipping. Neutron and fast-ion Dα (FIDA) diagnostics verify classical behavior of the off-axis beam ions in MHD-quiescent conditions. An initial physics experiment takes advantage of the downward steered beams to vary the fast-ion gradient ∇βf from centrally peaked to hollow. Systematic scans determine the stability and impact of reversed shear Alfvén eigenmodes and toroidal Alfvén eigenmodes as a function of ∇βf . Supported by US DOE under DE-FC02-04ER54698, SC-G903402, DE-AC05-00OR22725, DE-AC05-06OR23100, DE-AC52-07NA27344, DE-AC02-09CH11466, & DE-FG02-07ER54917.

  1. Design of Main Control Console Software in EAST Neutral Beam Injector's Control System for the First Beam Line

    Science.gov (United States)

    Wu, De-Yun; Hu, Chun-Dong; Sheng, Peng; Zhao, Yuan-Zhe; Zhang, Xiao-Dan; Cui, Qing-Long

    2013-10-01

    Neutral beam injector is one of the main plasma heating and plasma current driving methods for experimental advanced superconducting tokomaks (EAST). In order to realize visual operation of EAST neutral beam injector's control system (NBICS), main control console (MCC) is developed to work as the human-machine interface between the NBICS and physical operator. It can meet the requirements of visual control of NBICS by providing a user graphic interface. With the specific algorithms, the setup of power supply sequence is relatively independent and simple. Displaying the real-time feedback of the subsystems provides a reference for operators to monitor the status of the system. The MCC software runs on a Windows system and uses C++ language code while using client/server (C/S) mode, multithreading and cyclic redundancy check technology. The experimental results have proved that MCC provides a stability and reliability operation of NBICS and works as an effective man-machine interface at the same time.

  2. Vessel design and interfaces development for the 1 MV ITER Neutral Beam Injector and Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Rigato, Wladi [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy)], E-mail: wladi.rigato@igi.cnr.it; Dal Bello, Samuele; Marcuzzi, Diego; Rizzolo, Andrea [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy)

    2009-06-15

    In the framework of the design activities for the ITER Neutral Beam Injector (NBI) and full power neutral beam injector prototype, the vacuum vessel has been designed concurrently with the whole other components, and in particular with the Beam Source (BS) and the large Cryopumps, that strongly conditioned the design. The definition of the interfaces has been focused on the design for the 1 MV neutral beam injector prototype, anyway keeping to the absolute minimum the differences with respect to the ITER NBI Vessel. The Vacuum Vessel is composed of two separate parts which shall be welded on site: the Beam Line Vessel (BLV) and the Beam Source Vessel (BSV). Three main bolted lids are foreseen for horizontal and vertical access to the internal components. The vessel is composed of double wall and ribs in critical areas to minimize deformations and stresses under the atmospheric pressure load. New concepts for the Beam Source Support, Positioning and Tilting Systems have been developed and an engineering design has been carried out, able to satisfy precise requirements on stiffness, accuracy of regulation, vacuum compatibility, electric insulation and Remote Handling operation. These components and the BS have been fully integrated inside the BSV by means of support structures and vacuum feedthroughs for mechanical links allowing the transmission of motion and forces. The interfaces between the BLV and the Beam Line Components (BLCs) have been revised to be compatible with the new vessel design and the BLCs support frames. Further interfaces with the high voltage bushing, the vacuum pumping and the diagnostic systems have been considered. The number and the position of the diagnostic viewports were identified taking into account both diagnostics and structural requirements. Static, buckling and seismic analyses, based on EN 13445, have been performed considering operative and exceptional load cases. Requirements, criteria and design details are presented in the paper

  3. Overview of the negative ion based neutral beam injectors for ITER.

    Science.gov (United States)

    Schunke, B; Boilson, D; Chareyre, J; Choi, C-H; Decamps, H; El-Ouazzani, A; Geli, F; Graceffa, J; Hemsworth, R; Kushwah, M; Roux, K; Shah, D; Singh, M; Svensson, L; Urbani, M

    2016-02-01

    The ITER baseline foresees 2 Heating Neutral Beams (HNB's) based on 1 MeV 40 A D(-) negative ion accelerators, each capable of delivering 16.7 MW of deuterium atoms to the DT plasma, with an optional 3rd HNB injector foreseen as a possible upgrade. In addition, a dedicated diagnostic neutral beam will be injecting ≈22 A of H(0) at 100 keV as the probe beam for charge exchange recombination spectroscopy. The integration of the injectors into the ITER plant is nearly finished necessitating only refinements. A large number of components have passed the final design stage, manufacturing has started, and the essential test beds-for the prototype route chosen-will soon be ready to start.

  4. Generation of neutral atomic beams utilizing photodetachment by high power diode laser stacks

    Science.gov (United States)

    O'Connor, A. P.; Grussie, F.; Bruhns, H.; de Ruette, N.; Koenning, T. P.; Miller, K. A.; Savin, D. W.; Stützel, J.; Urbain, X.; Kreckel, H.

    2015-11-01

    We demonstrate the use of high power diode laser stacks to photodetach fast hydrogen and carbon anions and produce ground term neutral atomic beams. We achieve photodetachment efficiencies of ˜7.4% for H- at a beam energy of 10 keV and ˜3.7% for C- at 28 keV. The diode laser systems used here operate at 975 nm and 808 nm, respectively, and provide high continuous power levels of up to 2 kW, without the need of additional enhancements like optical cavities. The alignment of the beams is straightforward and operation at constant power levels is very stable, while maintenance is minimal. We present a dedicated photodetachment setup that is suitable to efficiently neutralize the majority of stable negative ions in the periodic table.

  5. Slow down of a globally neutral relativistic $e^-e^+$ beam shearing the vacuum

    CERN Document Server

    Alves, E P; Silveirinha, M G; Fonseca, R A; Silva, L O

    2015-01-01

    The microphysics of relativistic collisionless sheared flows is investigated in a configuration consisting of a globally neutral, relativistic $e^-e^+$ beam streaming through a hollow plasma/dielectric channel. We show through multidimensional PIC simulations that this scenario excites the Mushroom instability (MI), a transverse shear instability on the electron-scale, when there is no overlap (no contact) between the $e^-e^+$ beam and the walls of the hollow plasma channel. The onset of the MI leads to the conversion of the beam's kinetic energy into magnetic (and electric) field energy, effectively slowing down a globally neutral body in the absence of contact. The collisionless shear physics explored in this configuration may operate in astrophysical environments, particularly in highly relativistic and supersonic settings where macroscopic shear processes are stable.

  6. Overview of the negative ion based neutral beam injectors for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Schunke, B., E-mail: email@none.edu; Boilson, D.; Chareyre, J.; Choi, C.-H.; Decamps, H.; El-Ouazzani, A.; Geli, F.; Graceffa, J.; Hemsworth, R.; Kushwah, M.; Roux, K.; Shah, D.; Singh, M.; Svensson, L.; Urbani, M. [ITER Organization, Route de Vinon-sur-Verdon, 13115 St Paul lez Durance (France)

    2016-02-15

    The ITER baseline foresees 2 Heating Neutral Beams (HNB’s) based on 1 MeV 40 A D{sup −} negative ion accelerators, each capable of delivering 16.7 MW of deuterium atoms to the DT plasma, with an optional 3rd HNB injector foreseen as a possible upgrade. In addition, a dedicated diagnostic neutral beam will be injecting ≈22 A of H{sup 0} at 100 keV as the probe beam for charge exchange recombination spectroscopy. The integration of the injectors into the ITER plant is nearly finished necessitating only refinements. A large number of components have passed the final design stage, manufacturing has started, and the essential test beds—for the prototype route chosen—will soon be ready to start.

  7. Generation of neutral atomic beams utilizing photodetachment by high power diode laser stacks

    CERN Document Server

    O'Connor, A P; Grussie, F; Koenning, T P; Miller, K A; de Ruette, N; Stützel, J; Savin, D W; Urbain, X; Kreckel, H

    2015-01-01

    We demonstrate the use of high power diode laser stacks to photodetach fast hydrogen and carbon anions and produce ground term neutral atomic beams. We achieve photodetachment efficiencies of $\\sim$7.4\\% for H$^-$ at a beam energy of 10\\,keV and $\\sim$3.7\\% for C$^-$ at 28\\,keV. The diode laser systems used here operate at 975\\,nm and 808\\,nm, respectively, and provide high continuous power levels of up to 2\\,kW, without the need of additional enhancements like optical cavities. The alignment of the beams is straightforward and operation at constant power levels is very stable, while maintenance is minimal. We present a dedicated photodetachment setup that is suitable to efficiently neutralize the majority of stable negative ions in the periodic table.

  8. A thin column of dense plasma for space-charge neutralization of intense ion beams

    Science.gov (United States)

    Roy, P. K.; Seidl, P. A.; Anders, A.; Barnard, J. J.; Bieniosek, F. M.; Friedman, A.; Gilson, E. P.; Greenway, W.; Sefkow, A. B.; Jung, J. Y.; Leitner, M.; Lidia, S. M.; Logan, B. G.; Waldron, W. L.; Welch, D. R.

    2008-11-01

    Typical ion driven warm dense matter experiment requires a plasma density of 10^14/cm^3 to meet the challenge of np>nb, where np, and nb are the number densities of plasma and beam, respectively. Plasma electrons neutralize the space charge of an ion beam to allow a small spot of about 1-mm radius. In order to provide np>nb for initial warm, dense matter experiments, four cathodic arc plasma sources have been fabricated, and the aluminum plasma is focused in a focusing solenoid (8T field). A plasma probe with 37 collectors was developed to measure the radial plasma profile inside the solenoid. Results show that the plasma forms a thin column of diameter ˜7mm along the solenoid axis. The magnetic mirror effect, plasma condensation, and the deformation of the magnetic field due to eddy currents are under investigation. Data on plasma parameters and ion beam neutralization will be presented.

  9. Negative ion source development for a photoneutralization based neutral beam system for future fusion reactors

    Science.gov (United States)

    Simonin, A.; Agnello, R.; Bechu, S.; Bernard, J. M.; Blondel, C.; Boeuf, J. P.; Bresteau, D.; Cartry, G.; Chaibi, W.; Drag, C.; Duval, B. P.; de Esch, H. P. L.; Fubiani, G.; Furno, I.; Grand, C.; Guittienne, Ph; Howling, A.; Jacquier, R.; Marini, C.; Morgal, I.

    2016-12-01

    In parallel to the developments dedicated to the ITER neutral beam (NB) system, CEA-IRFM with laboratories in France and Switzerland are studying the feasibility of a new generation of NB system able to provide heating and current drive for the future DEMOnstration fusion reactor. For the steady-state scenario, the NB system will have to provide a high NB power level with a high wall-plug efficiency (η ˜ 60%). Neutralization of the energetic negative ions by photodetachment (so called photoneutralization), if feasible, appears to be the ideal solution to meet these performances, in the sense that it could offer a high beam neutralization rate (>80%) and a wall-plug efficiency higher than 60%. The main challenge of this new injector concept is the achievement of a very high power photon flux which could be provided by 3 MW Fabry-Perot optical cavities implanted along the 1 MeV D- beam in the neutralizer stage. The beamline topology is tall and narrow to provide laminar ion beam sheets, which will be entirely illuminated by the intra-cavity photon beams propagating along the vertical axis. The paper describes the present R&D (experiments and modelling) addressing the development of a new ion source concept (Cybele source) which is based on a magnetized plasma column. Parametric studies of the source are performed using Langmuir probes in order to characterize and compare the plasma parameters in the source column with different plasma generators, such as filamented cathodes, radio-frequency driver and a helicon antenna specifically developed at SPC-EPFL satisfying the requirements for the Cybele (axial magnetic field of 10 mT, source operating pressure: 0.3 Pa in hydrogen or deuterium). The paper compares the performances of the three plasma generators. It is shown that the helicon plasma generator is a very promising candidate to provide an intense and uniform negative ion beam sheet.

  10. Characterisation of neutral hydrogen beam by means of active balmer-a-spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wachter, C

    1999-01-01

    Neutral particle beams are used in thermal nuclear experiments for plasma heating and current drive, and as a diagnostic tool for active spectroscopy. Within the frame of this thesis eight viewing lines for H{sub {alpha}}-spectroscopy have been installed at the end of the injector to observe the fully established neutral beam. The viewing lines are all parallel to the horizontal plane and include small angles with the beam axis, in order to make use of the Doppler effect which separates the signals from the three energy components from each other and from the H{sub {alpha}}-emission of the thermal particles. A multi-Gaussian fit code has been applied to give the amplitudes, positions and widths of the Gauss shaped signals. From this data, the beam composition and, including the physics processes in the acceleration and neutralisation sections, the ion species fractions in the source have been calculated. Furthermore, the vertical density profile and an estimation of the absolute particle density distribution based on an absolute calibration resulted. From the line positions the exact acceleration voltage has been obtained. The line widths allow an estimate of the horizontal divergence. During this work, two ion sources, the 'Pagoda' and the 'Sourcette', have been investigated to obtain the ion species ratio and beam profile. The comparison of the spectroscopic with the calorimetric results gives a useful insight into the beam steering geometry. (author)

  11. Detailed design of the RF source for the 1 MV neutral beam test facility

    Energy Technology Data Exchange (ETDEWEB)

    Marcuzzi, D.; Palma, M. Dalla [Consorzio RFX, Euratom-ENEA Association, Corso Stati Uniti 4, I35127 Padova (Italy); Pavei, M. [Consorzio RFX, Euratom-ENEA Association, Corso Stati Uniti 4, I35127 Padova (Italy)], E-mail: mauro.pavei@igi.cnr.it; Heinemann, B.; Kraus, W.; Riedl, R. [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, Botzmannstr. 2, D-85748 Garching (Germany)

    2009-06-15

    In the framework of the EU activities for the development of the Neutral Beam Injector for ITER, the detailed design of the Radio Frequency (RF) driven negative ion source to be installed in the 1 MV ITER Neutral Beam Test Facility (NBTF) has been carried out. Results coming from ongoing R and D on IPP test beds [A. Staebler et al., Development of a RF-Driven Ion Source for the ITER NBI System, this conference] and the design of the new ELISE facility [B. Heinemann et al., Design of the Half-Size ITER Neutral Beam Source Test Facility ELISE, this conference] brought several modifications to the solution based on the previous design. An assessment was carried out regarding the Back-Streaming positive Ions (BSI+) that impinge on the back plates of the ion source and cause high and localized heat loads. This led to the redesign of most heated components to increase cooling, and to different choices for the plasma facing materials to reduce the effects of sputtering. The design of the electric circuit, gas supply and the other auxiliary systems has been optimized. Integration with other components of the beam source has been revised, with regards to the interfaces with the supporting structure, the plasma grid and the flexible connections. In the paper the design will be presented in detail, as well as the results of the analyses performed for the thermo-mechanical verification of the components.

  12. Impact of diagnostic neutral beam optimization on active spectroscopy in MST

    Science.gov (United States)

    Feng, Xiande; Nornberg, Mark. D.; den Hartog, Daniel. J.; Oliva, Steven. P.; Craig, Darren; Univ of Wisconsin, Madison Team; Wheaton College, IL Collaboration

    2016-10-01

    The hydrogen diagnostic neutral beam on MST provides local measurements of impurity ion emission through charge exchange recombination spectroscopy (CHERS) and of core-localized magnetic field through the motional Stark effect (MSE). The beam has been optimized to operate at 50kV, 4A steady beam current with 20ms beam pulse and 75% primary energy ion fraction. It's achieved by tuning the beam voltage, arc current, fuel line pressure, arc and high voltage module timing, and the magnetic isolation field. Electron density measurements in the ion source revealed that ion extraction is maximized under low density conditions which are thought to affect the shape of the ion sheath at the extraction grid. The sheath may be transitioning from a planar or convex shape at high density to one which is concave which helps focus the ion trajectories and produce higher beam current. With the improvements in beam operation, the CHERS signal is expected to increase by 20%-30%, and the Stark broadening is expected to increase by 10%. These signal increases will help resolve convolved fine-structure components in both analyses. Beam voltage ripple is also measured to better quantify the accuracy of spectral MSE and CHERS measurement. This work is supported by the U.S. DOE.

  13. Neutral Beam Injection System for the C-2W Field Reversed Configuration Experiment

    Science.gov (United States)

    Dunaevsky, Alexander; Ivanov, Alexander; Kolmogorov, Vyacheslav; Smirnov, Artem; Korepanov, Sergey; Binderbauer, Michl; TAE Team; BINP Team

    2016-10-01

    C-2U Field-Reversed Configuration (FRC) experiment proved substantial reduction in turbulence-driven losses via tangential neutral beam injection (NBI) coupled with electrically biased plasma guns at the plasma ends. Under such conditions, highly reproducible, advanced beam-driven FRCs were produced and sustained for times significantly longer (more than 5 ms) than all characteristic plasma decay times without beams. To further improve FRC sustainment and demonstrate the FRC ramp-up, the C-2U experimental device is undergoing a major upgrade. The upgrade, C-2W, will have a new NBI system producing a record total hydrogen beam power of 20 + MW in a 30ms pulse. The NBI system consists of eight positive-ion based injectors featuring flexible, modular design. Four out of eight NBI injectors have a capability to switch the beam energy during a shot from the initial 15 keV to 40 keV at a constant beam current. This feature allows to increase the beam energy and thereby optimize the beam-plasma coupling during the magnetic field ramp up. This presentation provides an overview of the C-2W NBI system, including the design of the switchable energy injectors, layout of the power supply system, and results of the prototype testing.

  14. Analysis on Pressure Distribution in HT-7 Neutral Beam Injection System

    Institute of Scientific and Technical Information of China (English)

    Zhu Wu; Chen Lian; Hu Chundong; Hu Liqun

    2005-01-01

    Neutral Beam Injection. (NBI) is an effective way to improve the efficiency of tokamak heating system. This article primarily introduces a work on the pressure distribution inside the tank of NBI heating system, especially inside the neutralizer, which is got by selecting a proper mathematical model and constructing a series of rational calculating formulas on pressure distribution. Furthermore, we simulate the pressure distribution by the Monte Carlo method. Comparing the result of simulation with that of theoretical calculation, we find that both the results are very close each other, showing their mutual validity.

  15. Stochastic Orbit Loss of Neutral Beam Ions From NSTX Due to Toroidal Alfven Eigenmode Avalanches

    Energy Technology Data Exchange (ETDEWEB)

    Darrow, D S; Fredrickson, E D; Gorelenkov, N N; Gorelenkova, M; Kubota, S; Medley, S S; Podesta, M; Shi, L

    2012-07-11

    Short toroidal Alfven eigenmode (TAE) avalanche bursts in the National Spherical Torus Experiment (NSTX) cause a drop in the neutron rate and sometimes a loss of neutral beam ions at or near the full injection energy over an extended range of pitch angles. The simultaneous loss of wide ranges of pitch angle suggests stochastic transport of the beam ions occurs. When beam ion orbits are followed with a guiding center code that incorporates plasma's magnetic equilibrium plus the measured modes, the predicted ranges of lost pitch angle are similar to those seen in the experiment, with distinct populations of trapped and passing orbits lost. These correspond to domains where the stochasticity extends in the orbit phase space from the region of beam ion deposition to the loss boundary.

  16. Enhancement of the neutral-beam stopping cross section in fusion plasmas due to multistep collision processes

    Energy Technology Data Exchange (ETDEWEB)

    Boley, C.D.; Janev, R.K.; Post, D.E.

    1983-10-01

    Multistep processes involving excited atomic states are found to produce a substantial increase in the stopping cross section for a neutral hydrogen beam injected into a plasma, and thus to reduce the beam penetration. For typical plasma and beam parameters of current large tokamak experiments, the stopping cross-sectional enhancement is found to vary from 25% to 50% depending on the beam energy, plasma density, and impurity level. For neutral hydrogen beams with energies greater than or equal to 500 keV, envisioned in tokamak amd mirror reactor designs, the enhancement can be as large as 80 to 90%.

  17. Logical and Timing Control for Diagnostic Neutral Beam Injection on HT-7

    Institute of Scientific and Technical Information of China (English)

    Du Shaowu; Ge Suoliang; Zhang Jian; Su Yu; Liu Baohua; Huang He

    2005-01-01

    The timing and master control logic (MCL) units are the most important function units of the diagnostic neutral beam (DNB) power supply control system. The units control the operation of nine power supply subsystems of the DNB system, and provide protection for the DNB system from faults such as beam source arc down. Based on the characteristics of the DNB power supply system, the timing and MCL units have been designed, fabricated and tested. Experiments prove that the timing unit is convenient, flexible and reliable, and the MCL is functional.

  18. Relative and absolute level populations in beam-foil-excited neutral helium

    Science.gov (United States)

    Davidson, J.

    1975-01-01

    Relative and absolute populations of 19 levels in beam-foil-excited neutral helium at 0.275 MeV have been measured. The singlet angular-momentum sequences show dependences on principal quantum number consistent with n to the -3rd power, but the triplet sequences do not. Singlet and triplet angular-momentum sequences show similar dependences on level excitation energy. Excitation functions for six representative levels were measured in the range from 0.160 to 0.500 MeV. The absolute level populations increase with energy, whereas the neutral fraction of the beam decreases with energy. Further, the P angular-momentum levels are found to be overpopulated with respect to the S and D levels. The overpopulation decreases with increasing principal quantum number.

  19. Neutral particle lithography: a simple solution to charge-related artefacts in ion beam proximity printing

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, J C; Craver, B P [Department of Electrical and Computer Engineering and Nanosystem Manufacturing Center, University of Houston, Houston, TX 77204-4005 (United States)

    2008-01-21

    Neutral particle lithography (NPL) is a high resolution, proximity exposure technique where a broad beam of energetic neutral atoms floods a stencil mask and transmitted beamlets transfer the mask pattern to resist on a substrate. It preserves the advantages of ion beam lithography, including extremely large depth-of-field, sub-5 nm resist scattering, and the near absence of diffraction, yet is intrinsically immune to charge-related artefacts including line-edge roughness and pattern placement errors due to charge accumulation on the mask and substrate. This paper reviews the principles of NPL, surveys recent advances in the field and discusses applications involving insulating substrates, large proximity gaps or ultra-small features where the approach has particular advantages.

  20. Conceptual design of the DEMO neutral beam injectors: main developments and R&D achievements

    Science.gov (United States)

    Sonato, P.; Agostinetti, P.; Bolzonella, T.; Cismondi, F.; Fantz, U.; Fassina, A.; Franke, T.; Furno, I.; Hopf, C.; Jenkins, I.; Sartori, E.; Tran, M. Q.; Varje, J.; Vincenzi, P.; Zanotto, L.

    2017-05-01

    The objectives of the nuclear fusion power plant DEMO, to be built after the ITER experimental reactor, are usually understood to lie somewhere between those of ITER and a ‘first of a kind’ commercial plant. Hence, in DEMO the issues related to efficiency and RAMI (reliability, availability, maintainability and inspectability) are among the most important drivers for the design, as the cost of the electricity produced by this power plant will strongly depend on these aspects. In the framework of the EUROfusion Work Package Heating and Current Drive within the Power Plant Physics and Development activities, a conceptual design of the neutral beam injector (NBI) for the DEMO fusion reactor has been developed by Consorzio RFX in collaboration with other European research institutes. In order to improve efficiency and RAMI aspects, several innovative solutions have been introduced in comparison to the ITER NBI, mainly regarding the beam source, neutralizer and vacuum pumping systems.

  1. Study of efficient high-power, high-energy neutral beams for the Reference Mirror Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Fink, J.H.; Barr, W.L.; Hamilton, G.W.

    1976-11-11

    An injector design for the Reference Mirror Reactor is described which uses negative ions created by charge-exchange in a cesium vapor cell and neutralized by photodetachment. Some of the innovations discussed include a continuously operating cathode for an LBL/LLL ion source, a negative ion beam line with cooled grids, a high voltage accelerator configuration with insulators shielded from the neutron and gamma flux, and cryopanels which continuously cycle between pumping and outgassing modes.

  2. CEDAR counter (internal part)

    CERN Multimedia

    1976-01-01

    Here on the mounting bench. The counter is a differential Cerenkov, corrected for chromaticity, able to differentiate pions from kaons up to 350 GeV. Counters of this type were used in all SPS hadron beams.

  3. The PRIMA Test Facility: SPIDER and MITICA test-beds for ITER neutral beam injectors

    Science.gov (United States)

    Toigo, V.; Piovan, R.; Dal Bello, S.; Gaio, E.; Luchetta, A.; Pasqualotto, R.; Zaccaria, P.; Bigi, M.; Chitarin, G.; Marcuzzi, D.; Pomaro, N.; Serianni, G.; Agostinetti, P.; Agostini, M.; Antoni, V.; Aprile, D.; Baltador, C.; Barbisan, M.; Battistella, M.; Boldrin, M.; Brombin, M.; Dalla Palma, M.; De Lorenzi, A.; Delogu, R.; De Muri, M.; Fellin, F.; Ferro, A.; Fiorentin, A.; Gambetta, G.; Gnesotto, F.; Grando, L.; Jain, P.; Maistrello, A.; Manduchi, G.; Marconato, N.; Moresco, M.; Ocello, E.; Pavei, M.; Peruzzo, S.; Pilan, N.; Pimazzoni, A.; Recchia, M.; Rizzolo, A.; Rostagni, G.; Sartori, E.; Siragusa, M.; Sonato, P.; Sottocornola, A.; Spada, E.; Spagnolo, S.; Spolaore, M.; Taliercio, C.; Valente, M.; Veltri, P.; Zamengo, A.; Zaniol, B.; Zanotto, L.; Zaupa, M.; Boilson, D.; Graceffa, J.; Svensson, L.; Schunke, B.; Decamps, H.; Urbani, M.; Kushwah, M.; Chareyre, J.; Singh, M.; Bonicelli, T.; Agarici, G.; Garbuglia, A.; Masiello, A.; Paolucci, F.; Simon, M.; Bailly-Maitre, L.; Bragulat, E.; Gomez, G.; Gutierrez, D.; Mico, G.; Moreno, J.-F.; Pilard, V.; Kashiwagi, M.; Hanada, M.; Tobari, H.; Watanabe, K.; Maejima, T.; Kojima, A.; Umeda, N.; Yamanaka, H.; Chakraborty, A.; Baruah, U.; Rotti, C.; Patel, H.; Nagaraju, M. V.; Singh, N. P.; Patel, A.; Dhola, H.; Raval, B.; Fantz, U.; Heinemann, B.; Kraus, W.; Hanke, S.; Hauer, V.; Ochoa, S.; Blatchford, P.; Chuilon, B.; Xue, Y.; De Esch, H. P. L.; Hemsworth, R.; Croci, G.; Gorini, G.; Rebai, M.; Muraro, A.; Tardocchi, M.; Cavenago, M.; D'Arienzo, M.; Sandri, S.; Tonti, A.

    2017-08-01

    The ITER Neutral Beam Test Facility (NBTF), called PRIMA (Padova Research on ITER Megavolt Accelerator), is hosted in Padova, Italy and includes two experiments: MITICA, the full-scale prototype of the ITER heating neutral beam injector, and SPIDER, the full-size radio frequency negative-ions source. The NBTF realization and the exploitation of SPIDER and MITICA have been recognized as necessary to make the future operation of the ITER heating neutral beam injectors efficient and reliable, fundamental to the achievement of thermonuclear-relevant plasma parameters in ITER. This paper reports on design and R&D carried out to construct PRIMA, SPIDER and MITICA, and highlights the huge progress made in just a few years, from the signature of the agreement for the NBTF realization in 2011, up to now—when the buildings and relevant infrastructures have been completed, SPIDER is entering the integrated commissioning phase and the procurements of several MITICA components are at a well advanced stage.

  4. Physics design of the injector source for ITER neutral beam injector (invited).

    Science.gov (United States)

    Antoni, V; Agostinetti, P; Aprile, D; Cavenago, M; Chitarin, G; Fonnesu, N; Marconato, N; Pilan, N; Sartori, E; Serianni, G; Veltri, P

    2014-02-01

    Two Neutral Beam Injectors (NBI) are foreseen to provide a substantial fraction of the heating power necessary to ignite thermonuclear fusion reactions in ITER. The development of the NBI system at unprecedented parameters (40 A of negative ion current accelerated up to 1 MV) requires the realization of a full scale prototype, to be tested and optimized at the Test Facility under construction in Padova (Italy). The beam source is the key component of the system and the design of the multi-grid accelerator is the goal of a multi-national collaborative effort. In particular, beam steering is a challenging aspect, being a tradeoff between requirements of the optics and real grids with finite thickness and thermo-mechanical constraints due to the cooling needs and the presence of permanent magnets. In the paper, a review of the accelerator physics and an overview of the whole R&D physics program aimed to the development of the injector source are presented.

  5. Ion Source for Neutral beam injection meant for plasma and magnetic field diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Vainionpaa, Jaakko Hannes; Leung, Ka Ngo; Gough, Richard A.; Kwan, Joe W.; Levinton, Fred

    2007-06-01

    At the Lawrence Berkeley National Laboratory (LBNL) a diagnostic neutral beam injection system for measuring plasma parameters, flow velocity, and local magnetic field is being developed. The systems is designed to have a 90 % proton fraction and small divergence with beam current at 5-6 A and a pulse length of {approx}1 s occurring once every 1-2 min. The ion source needs to generate uniform plasma over a large (8 cm x 5 cm) extraction area. For this application, we have compared RF driven multicusp ion sources operating with either an external or an internal antenna in similar ion source geometry. The ion beam will be made of an array of six sheet-shaped beamlets. The design is optimized using computer simulation programs.

  6. Physics design of the injector source for ITER neutral beam injector (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Antoni, V.; Agostinetti, P.; Aprile, D.; Chitarin, G.; Fonnesu, N.; Marconato, N.; Pilan, N.; Sartori, E.; Serianni, G., E-mail: gianluigi.serianni@igi.cnr.it; Veltri, P. [Consorzio RFX, Associazione EURATOM-ENEA sulla fusione, c.so Stati Uniti 4, 35127 Padova (Italy); Cavenago, M. [INFN-LNL, viale dell’Università n. 2, 35020 Legnaro (Italy)

    2014-02-15

    Two Neutral Beam Injectors (NBI) are foreseen to provide a substantial fraction of the heating power necessary to ignite thermonuclear fusion reactions in ITER. The development of the NBI system at unprecedented parameters (40 A of negative ion current accelerated up to 1 MV) requires the realization of a full scale prototype, to be tested and optimized at the Test Facility under construction in Padova (Italy). The beam source is the key component of the system and the design of the multi-grid accelerator is the goal of a multi-national collaborative effort. In particular, beam steering is a challenging aspect, being a tradeoff between requirements of the optics and real grids with finite thickness and thermo-mechanical constraints due to the cooling needs and the presence of permanent magnets. In the paper, a review of the accelerator physics and an overview of the whole R and D physics program aimed to the development of the injector source are presented.

  7. Considerations for the development of neutral beam injection for fusion reactors or DEMO

    Science.gov (United States)

    Hemsworth, R. S.; Boilson, D.

    2017-08-01

    Neutral beam injection (NBI) has been the most successful heating scheme applied to fusion devices, the majority of which have been based on the acceleration and neutralization in a gas target of accelerated positive ions. For large fusion devices such as ITER, DEMO and fusion reactors, beam energies of the order of 0.5 MeV per nucleon or higher are required to penetrate deeply into the fusing plasma, and thus to heat the plasma in the most important region, i.e. near the poloidal axis of the device, and to drive current in the plasma. Because the efficiency of neutralization of positive ions in a gas target becomes unacceptably low at energies above ≈100 keV/nucleon, future injectors will be based on the neutralization of negative ions, either in a gas target, by photons or in a plasma target. So far only two systems based on negative ions have been used on fusion devices, at JT-60U and at LHD, both based on neutralization in a gas target. The injectors for ITER will also use a gas target, but the energy and operating environment are reactor and DEMO relevant. Also the ITER injectors will have to operate for pulse lengths orders of magnitude higher than all previous NBI systems. In this paper the R&D required for an NBI system for a reactor, or DEMO, is considered against the background of the ITER NBI system development, and the main elements of the required R&D are identified.

  8. Evaluation of tritium diffusion through the Neutral Beam Injector calorimeter panel

    Energy Technology Data Exchange (ETDEWEB)

    Borgognoni, Fabio [ENEA, Dipartimento Fusione Tecnologie e Presidio Nucleare, C.R. ENEA Frascati, Via E. Fermi 45, Frascati (RM) I-00044 (Italy)], E-mail: fabio.borgognoni@frascati.enea.it; Moriani, Andrea [ENEA, Dipartimento Fusione Tecnologie e Presidio Nucleare, C.R. ENEA Frascati, Via E. Fermi 45, Frascati (RM) I-00044 (Italy); Sandri, Sandro [ENEA, Dipartimento Biotecnologie, Agroindustria e Protezione della Salute Istituto di Radioprotezione - C.R. ENEA Frascati, Via E. Fermi 45, Frascati (RM) I-00044 (Italy); Tosti, Silvano [ENEA, Dipartimento Fusione Tecnologie e Presidio Nucleare, C.R. ENEA Frascati, Via E. Fermi 45, Frascati (RM) I-00044 (Italy)

    2009-06-15

    The Neutral Beam Test Facility (NBTF) to be realized in Padoa will test the Neutral Beam Injection (NBI), one of the Heating and Current Drive Systems foreseen for ITER. The NBI is based on the acceleration of hydrogen or deuterium negative ions up to 1 MeV. This work has been aimed at assessing the tritium release from the NBTF in order to provide data for the safety analysis. In particular, the diffusion of the tritium through the neutral beam target material (the CuCrZr alloy calorimeter panels) has been assessed by using literature data of the diffusion coefficient. The tritium generated inside the calorimeter panels moves into both the vacuum and water side: the tritium diffusion flux has been evaluated during the beam-on (200 deg. C) and the beam-off (20 deg. C) phases of the NBTF experiments consisting of an interim campaign and a final test. The penetration depth of the tritium through the 2 mm thick CuCrZr alloy material has been also evaluated by using a Monte-Carlo code. As main result, the assessed diffusion flux of tritium during both the beam-on and the beam-off phases are modest. In fact, at the end of the interim campaign (100 days), about the 96% of the all generated tritium (626.5 MBq) exits the calorimeter while the residual tritium inventory (25 MBq) leaves the copper alloy with a diffusion time of about 1 month. At the end of the final test (14 days) about the 99% of the total generated tritium (1.023 x 10{sup 4} MBq) leaves the copper alloy and the remaining tritium inventory (152.2 MBq) is released by about 32 days. In both the interim campaign and the final test, more than the 99% of the total tritium is transferred into the vacuum side of the calorimeter panel while negligible tritium amounts enter the cooling water system thus showing a very low impact on the environ0010me.

  9. Neutral-beam current-driven high-poloidal-beta operation of the DIII-D tokamak

    Science.gov (United States)

    Simonen, T. C.; Matsuoka, M.; Bhadra, D. K.; Burrell, K. H.; Callis, R. W.; Chance, M. S.; Chu, M. S.; Greene, J. M.; Groebner, R. J.; Harvey, R. W.; Hill, D. N.; Kim, J.; Lao, L.; Petersen, P. I.; Porter, G. D.; St. John, H.; Stallard, B. W.; Stambaugh, R. D.; Strait, E. J.; Taylor, T. S.

    1988-10-01

    Neutral-beam current-drive experiments in the DIII-D tokamak with a single null poloidal divertor are described. A plasma current of 0.34 MA has been sustained by neutral beams alone, and the energy confinement is of H-mode quality. Poloidal β values reach 3.5 without disruption or coherent magnetic activity suggesting that these plasmas may be entering the second stability regime.

  10. Improvement of a block co-polymer (PS-b-PMMA)-masked silicon etch profile using a neutral beam

    Science.gov (United States)

    Yun, Deokhyun; Park, Jinwoo; Kim, Hwasung; Mun, Jeongho; Kim, Sangouk; Kim, Kyongnam; Yeom, Geunyoung

    2016-09-01

    Bottom-up block copolymer (BCP) lithography mediated by self-assembly of polystyrene (PS)/poly-methyl methacrylate (PMMA) is widely used as an alternative patterning method for various deep nanoscale devices, such as optical devices and transistors, replacing conventional top-down photolithography. However, the nanoscale BCP mask features formed on the substrates after direct self-assembly of BCP tend to be easily damaged during exposure to the following plasma processing. In this study, silicon masked with a nanoscale BCP mask (PS) was etched by irradiating with a Cl2/Ar neutral beam in addition to a Cl2/Ar ion beam, and the effect of a Cl2/Ar neutral beam instead of a Cl2/Ar ion beam on damage to the PS mask and the silicon etch characteristics of nanodevices was investigated. The results show that the use of a neutral beam instead of an ion beam decreased degradation of the BCP mask during etching; therefore, a more anisotropic silicon etch profile in addition to improved etch selectivity of silicon compared to the BCP mask was observed. Moreover, by using the neutral beam, the sidewall roughness and sidewall angle also improved due to the decreased surface charge and reduced damage to the nanoscale PS mask resulting from use of a highly directional radical beam instead of a conventional ion-based beam.

  11. Design of a Fast Neutral He Beam System for Feasibility Study of Charge-Exchange Alpha-Particle Diagnostics in a Thermonuclear Fusion Reactor

    CERN Document Server

    Shinto, Katsuhiro; Kitajima, Sumio; Kiyama, Satoru; Nishiura, Masaki; Sasao, Mamiko; Sugawara, Hiroshi; Takenaga, Mahoko; Takeuchi, Shu; Wada, Motoi

    2005-01-01

    For alpha-particle diagnostics in a thermonuclear fusion reactor, neutralization using a fast (~2 MeV) neutral He beam produced by the spontaneous electron detachment of a He- is considered most promising. However, the beam transport of produced fast neutral He has not been studied, because of difficulty for producing high-brightness He- beam. Double-charge-exchange He- sources and simple beam transport systems were developed and their results were reported in the PAC99* and other papers.** To accelerate an intense He- beam and verify the production of the fast neutral He beam, a new test stand has been designed. It consists of a multi-cusp He+

  12. Progress on the Implementation of a Neutral Beam for the Lithium Tokamak eXperiment-Beta

    Science.gov (United States)

    Merino, Enrique; Kozub, Thomas; Boyle, Dennis; Majeski, Richard; Kaita, Robert; Smirnov, Artem; Catalano, Ryan

    2016-10-01

    In the Lithium Tokamak eXperiment (LTX), good performance discharges have been achieved with reduced-recycling lithium walls. Two hydrogen neutral beams (NB) have been loaned to the LTX project by Tri-Alpha Energy, Inc. To further improve plasma parameters, one of these neutral beams is being installed as part of an upgrade to LTX (LTX-Beta). Current ohmic input power in LTX is less than 100 kW. The NB will provide core plasma fueling with up to 700 kW of injected power. Requirements for accommodating the NB include the addition of injection and beam-dump ports on the vessel, and their designs have been finalized. Progress has also been made on the NB power supplies, including the preparation of a new room to accommodate them. A description of these activities and the status of other improvements to LTX for LTX-Beta will be presented. Work supported by US DOE contracts DE-AC02- 09CH11466 and DE-AC05- 00OR22725.

  13. Neutral beam injector oxygen impurity measurements and concentration reduction via gettering processes. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Kane, R.J.; Hsu, W.L.; Kerr, R.G.; Mills, B.E.; Poulsen, P.; Hibbs, S.

    1984-12-01

    We have measured the reduction of oxygen impurity levels by means of gettering within the arc chambers of the TMX-U neutral-beam injectors using the TMX-U neutral-beam test stand. Our analysis incorporated silicon surface-probe measurements and optical Doppler-shift measurements of the hydrogen alpha spectra of deuterium atoms with energies appropriate for D/sub 2/O parentage. Without gettering, the Auger electron spectroscopy analysis of an exposed silicon sample showed a large oxygen peak below the surface peak with a concentration equivalence of approximately 2% for an accelerated beam. After gettering, with either titanium or chromium getters, optical monochromator data indicated a reduction in the oxygen concentration of at least a factor of 10 whereas Auger spectroscopy data showed at least a factor-of-eight reduction. Other metallic impurities remained below the level of detection even after gettering. Additional effects observed during this study include a change in the accelerated deuterium species concentrations, loss of gettering activity, loss of arc operation, and a change in arc performance due to arc chamber gas absorption during operation.

  14. Neutral beam injector oxygen impurity measurements and concentration reduction via gettering processes

    Energy Technology Data Exchange (ETDEWEB)

    Kane, R.J.; Hsu, W.L.; Kerr, R.G.; Mills, B.E.; Poulsen, P.; Hibbs, S.

    1984-10-01

    The reduction of oxygen impurity levels by means of gettering within the arc chambers of the TMX-U neutral beam injectors has been measured. The TMX-U Neutral Beam Test Stand was used for this experiment. Analysis incorporated silicon surface probes and optical Doppler-shift measurements of the Lyman alpha spectra of deuterium atoms with energies appropriate for D/sub 2/O parentage. Without gettering, the Auger electron spectroscopy analysis of an exposed silicon sample showed a large oxygen peak below the surface peak with a concentration equivalent of approximately 2% for an accelerated beam. After gettering, with either titanium or chromium getters, the oxygen concentration was reduced by at least a factor of 10 according to optical monochromator data, and at least a factor of 8 from Auger spectroscopy data. Simultaneously, other metallic impurities were not increased substantially as a result of gettering. Additional effects observed during this study include a change in the accelerated deuterium species concentrations, loss of gettering activity and arc operation, and a change in arc performance from arc chamber gas absorption during operation.

  15. Feasibility Study on a Neutral Beam Diagnostic Injector for TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, K. J.; Balbin, R.; Lopez-Fraguas, A.

    2003-07-01

    A diagnostic neutral beam system is proposed for the TJ-II stellarator. The main goal of installing such a system in TJ-II is to increase the signal to noise ratio and provide spatial resolution in diagnostic systems based on Charge Exchange Recombination Spectroscopy and Neutral Particle Analysis, while also opening up new opportunities for physics studies in this magnetically confined plasma device. After outlining the unique characteristics of the TJ-II and reviewing available diagnostic injector systems, the compact system selected for TJ-II is presented together with estimates of the resulting increased signal levels Finally other important aspects are discussed, in particular its location and orientation, as well as possible solutions to avoid perturbing the TJ-II magnetic configurations in the heliac device. (Author) 31 refs.

  16. Transmission of the Neutral Beam Heating Beams at TJ-II; Transmision del Haz de Neutros de Calentamiento en TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes Lopez, C.

    2007-09-27

    Neutral beam injection heating has been development for the TJ-II stellarator. The beam has a port-through power between 700-1500 kW and injection energy 40 keV. The sensibility of the injection system to the changes of several parameters is analysed. Beam transmission is limited by losses processes since beam is born into the ions source until is coming into the fusion machine. For the beam transmission optimization several beam diagnostics have been developed. A carbon fiber composite (CFC) target calorimeter has been installed at TJ-II to study in situ the power density distribution of the neutral beams. The thermographic print of the beam can be recorded and analysed in a reliable way due to the highly anisotropic thermal conductivity of the target material. With the combined thermographic and calorimetric measurements it has been possible to determine the power density distribution of the beam. It has been found that a large beam halo is present, which can be explained by the extreme misalignment of the grids. This kind of halo has a deleterious effect on beam transport and must be minimized in order to improve the plasma heating capability of the beams. (Author) 155 refs.

  17. Radiation hardness test of the Philips Digital Photon Counter with proton beam

    Science.gov (United States)

    Barnyakov, M. Yu.; Frach, T.; Kononov, S. A.; Kuyanov, I. A.; Prisekin, V. G.

    2016-07-01

    The Philips Digital Photon Counter (DPC) is a silicon photomultiplier combining Geiger-mode avalanche photodiodes (G-APD) and dedicated readout electronics in the same chip. The DPC is a promising photon sensor for future RICH detectors. A known issue of G-APD is its sensitivity to radiation damage. Two DPC sensors were tested using 800 MeV/c protons. An increase of dark counting rate with proton fluence up to 4 ·1011cm-2 has been measured.

  18. Applying Remote Handling Attributes to the ITER Neutral Beam Cell Monorail Crane

    CERN Document Server

    Crofts, O; Raimbach, J; Tesini, A; Choi, C-H; Damiani, C; Van Uffelen, M

    2013-01-01

    The maintenance requirements for the equipment in the ITER Neutral Beam Cell requires components to be lifted and transported within the cell by remote means. To meet this requirement, the provision of an overhead crane with remote handling capabilities has been initiated. The layout of the cell has driven the design to consist of a monorail crane that travels on a branched monorail track attached to the cell ceiling. This paper describes the principle design constraints and how the remote handling attributes were applied to the concept design of the monorail crane, concentrating on areas where novel design solutions have been required and on the remote recovery requirements and solutions.

  19. Design of Control Server Application Software for Neutral Beam Injection System

    Institute of Scientific and Technical Information of China (English)

    施齐林; 胡纯栋; 盛鹏; 宋士化

    2012-01-01

    For the remote control of a neutral beam injection (NBI) system, a software NBIcsw is developed to work on the control server. It can meet the requirements of data transmission and operation-control between the NBI measurement and control layer (MCL) and the remote monitoring layer (RML). The NBIcsw runs on a Linux system, developed with client/server (C/S) mode and multithreading technology. It is shown through application that the software is with good efficiency.

  20. Solid state generator for powerful radio frequency ion sources in neutral beam injection systems

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, W.; Fantz, U.; Heinemann, B.; Franzen, P.

    2015-02-15

    Radio frequency ion sources used in neutral beam injection systems (NBI) of fusion machines are currently supplied by self-excited RF generators. These generators have both a low power efficiency and a limited frequency stability, therefore transistorized amplifiers are being considered for the power supply of the next generation of RF sources. A 75 kW generator, originally designed for broadcasting, has been tested with a negative ion source. High operational reliability and a very good matching to the plasma load has been demonstrated. These results make this generator type a very promising candidate for future NBI systems.

  1. Status of PRIMA, the test facility for ITER neutral beam injectors

    Science.gov (United States)

    Sonato, P.; Antoni, V.; Bigi, M.; Chitarin, G.; Luchetta, A.; Marcuzzi, D.; Pasqualotto, R.; Pomaro, N.; Serianni, G.; Toigo, V.; Zaccaria, P.; ITER International Team

    2013-02-01

    The ITER project requires additional heating by two neutral beam injectors, each accelerating to 1MV a 40A beam of negative deuterons, delivering to the plasma about 17MW up to one hour. As these requirements have never been experimentally met, it was decided to build a test facility, PRIMA (Padova Research on ITER Megavolt Accelerator), in Italy, including a full-size negative ion source, SPIDER, and a prototype of the whole ITER injector, MITICA, aiming to develop the heating injectors to be installed in ITER. The Japan and the India Domestic Agencies participate in the PRIMA enterprise; European laboratories, such as KIT-Karlsruhe, IPP-Garching, CCFE-Culham, CEA-Cadarache and others are also cooperating. In the paper the main requirements are discussed and the design of the main components and systems are described.

  2. Current Control in ITER Steady State Plasmas With Neutral Beam Steering

    Energy Technology Data Exchange (ETDEWEB)

    R.V. Budny

    2009-09-10

    Predictions of quasi steady state DT plasmas in ITER are generated using the PTRANSP code. The plasma temperatures, densities, boundary shape, and total current (9 - 10 MA) anticipated for ITER steady state plasmas are specified. Current drive by negative ion neutral beam injection, lower-hybrid, and electron cyclotron resonance are calculated. Four modes of operation with different combinations of current drive are studied. For each mode, scans with the NNBI aimed at differing heights in the plasma are performed to study effects of current control on the q profile. The timeevolution of the currents and q are calculated to evaluate long duration transients. Quasi steady state, strongly reversed q profiles are predicted for some beam injection angles if the current drive and bootstrap currents are sufficiently large.

  3. High power 1 MeV neutral beam system and its application plan for the international tokamak experimental reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hemsworth, R.S. [ITER Joint Central Team, Naka, Ibaraki (Japan)

    1997-03-01

    This paper describes the Neutral Beam Injection system which is presently being designed for the International Tokamak Experimental Reactor, ITER, in Europe Japan and Russia, with co-ordination by the Joint Central Team of ITER at Naka, Japan. The proposed system consists of three negative ion based neutral injectors, delivering a total of 50 MW of 1 MeV D{sup 0} to the ITER plasma for a pulse length of >1000 s. Each injectors uses a single caesiated volume arc discharge negative ion source, and a multi-grid, multi-aperture accelerator, to produce about 40 A of 1 MeV D{sup -}. This will be neutralized by collisions with D{sub 2} in a sub-divided gas neutralizer, which has a conversion efficiency of about 60%. The charged fraction of the beam emerging from the neutralizer is dumped in an electrostatic residual ion dump. A water cooled calorimeter can be moved into the beam path to intercept the neutral beam, allowing commissioning of the injector independent of ITER. ITER is scheduled to produce its first plasma at the beginning of 2008, and the planning of the R and D, construction and installation foresees the neutral injection system being available from the start of ITER operations. (author)

  4. Fast control and data acquisition in the neutral beam test facility

    Energy Technology Data Exchange (ETDEWEB)

    Luchetta, A., E-mail: adriano.luchetta@igi.cnr.it; Manduchi, G.; Taliercio, C.

    2014-05-15

    Highlights: • The paper describes the fast control and data acquisition in the ITER neutral beam test facility. • The usage of real time control in ion beam generation and extraction is proposed. • Real time management of breakdowns is described. • The implementation of event-driven data acquisition is reported. - Abstract: Fast control and data acquisition are required in the ion source test bed of the ITER neutral beam test facility, referred to as SPIDER. Fast control will drive the operation of the power supply systems with particular reference to special asynchronous events, such as the breakdowns. These are short-circuits among grids or between grids and vessel that can occur repeatedly during beam operation. They are normal events and, as such, they will be managed by the fast control system. Cycle time associated to such fast control is down to hundreds of microseconds. Fast data acquisition is required when breakdowns occur. Event-driven data acquisition is triggered in real time by fast control at the occurrence of each breakdown. Pre- and post-event samples are acquired, allowing capturing information on transient phenomena in a whole time-window centered on the event. Sampling rate of event-driven data acquisition is up to 5 MS/s. Fast data acquisition may also be independent of breakdowns as in the case of the cavity ring-down spectroscopy where data chunks are acquired at 100 MS/s in bursts of 1.5 ms every 100 ms and are processed in real time to produce derived measurements. The paper after the description of the SPIDER fast control and data acquisition application will report the system design based on commercially available hardware and the MARTe and MDSplus software frameworks. The results obtained by running a full prototype of the fast control and data acquisition system are also reported and discussed. They demonstrate that all SPIDER fast control and data acquisition requirements can be met in the prototype solution.

  5. Ion beam transport: modelling and experimental measurements on a large negative ion source in view of the ITER heating neutral beam

    Science.gov (United States)

    Veltri, P.; Sartori, E.; Agostinetti, P.; Aprile, D.; Brombin, M.; Chitarin, G.; Fonnesu, N.; Ikeda, K.; Kisaki, M.; Nakano, H.; Pimazzoni, A.; Tsumori, K.; Serianni, G.

    2017-01-01

    Neutral beam injectors are among the most important methods of plasma heating in magnetic confinement fusion devices. The propagation of the negative ions, prior to their conversion into neutrals, is of fundamental importance in determining the properties of the beam, such as its aiming and focusing at long-distances, so as to deposit the beam power in the proper position inside the confined plasma, as well as to avoid interaction with the material surfaces along the beam path. The final design of the ITER Heating Neutral Beam prototype has been completed at Consorzio RFX (Padova, Italy), in the framework of a close collaboration with European, Japanese and Indian fusion research institutes. The physical and technical rationales on which the design is based were essentially driven by numerical modelling of the relevant physical processes, and the same models and codes will be useful to design the DEMO neutral beam injector in the near future. This contribution presents a benchmark study of the codes used for this purpose, by comparing their results against the measures performed in an existing large-power device, hosted at the National Institute for Fusion Science, Japan. In particular, the negative ion formation and acceleration are investigated. A satisfactory agreement was found between codes and experiments, leading to an improved understanding of beam transport dynamics. The interpretation of the discrepancies identified in previous works, possibly related to the non-uniformity of the extracted negative ion current, is also presented.

  6. Advanced numerical studies of the neutralized drift compression of intense ion beam pulses

    Directory of Open Access Journals (Sweden)

    Adam B. Sefkow

    2007-10-01

    Full Text Available Longitudinal bunch compression of intense ion beams for warm dense matter and heavy ion fusion applications occurs by imposing an axial velocity tilt onto an ion beam across the acceleration gap of a linear induction accelerator, and subsequently allowing the beam to drift through plasma in order to neutralize its space-charge and current as the pulse compresses. The detailed physics and implications of acceleration gap effects and focusing aberration on optimum longitudinal compression are quantitatively reviewed using particle-in-cell simulations, showing their dependence on many system parameters. Finite-size gap effects are shown to result in compression reduction, due to an increase in the effective longitudinal temperature imparted to the beam, and a decrease in intended fractional tilt. Sensitivity of the focal plane quality to initial longitudinal beam temperature is explored, where slower particles are shown to experience increased levels of focusing aberration compared to faster particles. A plateau effect in axial compression is shown to occur for larger initial pulse lengths, where the increases in focusing aberration over the longer drift lengths involved dominate the increases in relative compression, indicating a trade-off between current compression and pulse duration. The dependence on intended fractional tilt is also discussed and agrees well with theory. A balance between longer initial pulse lengths and larger tilts is suggested, since both increase the current compression, but have opposite effects on the final pulse length, drift length, and amount of longitudinal focusing aberration. Quantitative examples are outlined that explore the sensitive dependence of compression on the initial kinetic energy and thermal distribution of the beam particles. Simultaneous transverse and longitudinal current density compression can be achieved in the laboratory using a strong final-focus solenoid, and simulations addressing the effects

  7. Real-time control and data-acquisition system for high-energy neutral-beam injectors

    Energy Technology Data Exchange (ETDEWEB)

    Glad, A S; Jacobson, V

    1981-12-01

    The need for a real-time control system and a data acquisition, processing and archiving system operating in parallel on the same computer became a requirement on General Atomic's Doublet III fusion energy project with the addition of high energy neutral beam injectors. The data acquisition processing and archiving system is driven from external events and is sequenced through each experimental shot utilizing ModComp's intertask message service. This system processes, archives and displays on operator console CRTs all physics diagnostic data related to the neutral beam injectores such as temperature, beam alignment, etc. The real-time control system is data base driven and provides periodic monitoring and control of the numerous dynamic subsystems of the neutral beam injectors such as power supplies, timing, water cooling, etc.

  8. Control of power, torque, and instability drive using in-shot variable neutral beam energy in tokamaks

    Science.gov (United States)

    Pace, D. C.; Collins, C. S.; Crowley, B.; Grierson, B. A.; Heidbrink, W. W.; Pawley, C.; Rauch, J.; Scoville, J. T.; Van Zeeland, M. A.; Zhu, Y. B.; The DIII-D Team

    2017-01-01

    A first-ever demonstration of controlling power and torque injection through time evolution of neutral beam energy has been achieved in recent experiments at the DIII-D tokamak (Luxon 2002 Nucl. Fusion 42 614). Pre-programmed waveforms for the neutral beam energy produce power and torque inputs that can be separately and continuously controlled. Previously, these inputs were tailored using on/off modulation of neutral beams resulting in large perturbations (e.g. power swings of over 1 MW). The new method includes, importantly for experiments, the ability to maintain a fixed injected power while varying the torque. In another case, different beam energy waveforms (in the same plasma conditions) produce significant changes in the observed spectrum of beam ion-driven instabilities. Measurements of beam ion loss show that one energy waveform results in the complete avoidance of coherent losses due to Alfvénic instabilities. This new method of neutral beam operation is intended for further application in a variety of DIII-D experiments including those concerned with high-performance steady state scenarios, fast particle effects, and transport in the low torque regime. Developing this capability would provide similar benefits and improved plasma control for other magnetic confinement fusion facilities.

  9. Current profile redistribution driven by neutral beam injection in a reversed-field pinch

    Science.gov (United States)

    Parke, E.; Anderson, J. K.; Brower, D. L.; Den Hartog, D. J.; Ding, W. X.; Johnson, C. A.; Lin, L.

    2016-05-01

    Neutral beam injection in reversed-field pinch (RFP) plasmas on the Madison Symmetric Torus [Dexter et al., Fusion Sci. Technol. 19, 131 (1991)] drives current redistribution with increased on-axis current density but negligible net current drive. Internal fluctuations correlated with tearing modes are observed on multiple diagnostics; the behavior of tearing mode correlated structures is consistent with flattening of the safety factor profile. The first application of a parametrized model for island flattening to temperature fluctuations in an RFP allows inferrence of rational surface locations for multiple tearing modes. The m = 1, n = 6 mode is observed to shift inward by 1.1 ± 0.6 cm with neutral beam injection. Tearing mode rational surface measurements provide a strong constraint for equilibrium reconstruction, with an estimated reduction of q0 by 5% and an increase in on-axis current density of 8% ± 5%. The inferred on-axis current drive is consistent with estimates of fast ion density using TRANSP [Goldston et al., J. Comput. Phys. 43, 61 (1981)].

  10. Current profile redistribution driven by neutral beam injection in a reversed-field pinch

    Energy Technology Data Exchange (ETDEWEB)

    Parke, E. [Department of Physics and Astronomy, University of California Los Angeles 475 Portola Plaza, Los Angeles, California 90095 (United States); Department of Physics, University of Wisconsin-Madison 1150 University Ave., Madison, Wisconsin 53706 (United States); Anderson, J. K.; Den Hartog, D. J. [Department of Physics, University of Wisconsin-Madison 1150 University Ave., Madison, Wisconsin 53706 (United States); Brower, D. L.; Ding, W. X.; Lin, L. [Department of Physics and Astronomy, University of California Los Angeles 475 Portola Plaza, Los Angeles, California 90095 (United States); Johnson, C. A. [Department of Physics, University of Wisconsin-Madison 1150 University Ave., Madison, Wisconsin 53706 (United States); Department of Physics, Auburn University 206 Allison Laboratory, Auburn, Alabama 36849 (United States)

    2016-05-15

    Neutral beam injection in reversed-field pinch (RFP) plasmas on the Madison Symmetric Torus [Dexter et al., Fusion Sci. Technol. 19, 131 (1991)] drives current redistribution with increased on-axis current density but negligible net current drive. Internal fluctuations correlated with tearing modes are observed on multiple diagnostics; the behavior of tearing mode correlated structures is consistent with flattening of the safety factor profile. The first application of a parametrized model for island flattening to temperature fluctuations in an RFP allows inferrence of rational surface locations for multiple tearing modes. The m = 1, n = 6 mode is observed to shift inward by 1.1 ± 0.6 cm with neutral beam injection. Tearing mode rational surface measurements provide a strong constraint for equilibrium reconstruction, with an estimated reduction of q{sub 0} by 5% and an increase in on-axis current density of 8% ± 5%. The inferred on-axis current drive is consistent with estimates of fast ion density using TRANSP [Goldston et al., J. Comput. Phys. 43, 61 (1981)].

  11. Enhancement of laser to X-ray conversion by counter-propagating laser beams irradiating thin gold targets

    Science.gov (United States)

    Zhao, Y.; Ge, Z. Y.; Ma, Y. Y.; Yang, X. H.; Xu, B. B.; Ramis, R.

    2017-03-01

    X-ray emission from laser irradiating solid target is an important X-ray source for various potential applications. Counter-propagating (C-P) laser beams configuration is proposed to enhance the laser to X-ray conversion efficiency (CE) from laser irradiating solid targets. One-dimensional radiation hydrodynamics simulations show that the total X-ray CE for the C-P lasers case is as high as 65%, which has a 13% improvement compared with the single laser case. The improvement is mainly caused by the enlarged radiation region, and the enhancement of X-ray emission is from soft X-ray. Detailed energy term distributions and influences of the foil thickness on the X-ray CEs for both cases are presented. It is found that the enhancement of radiation is attributed to lower thermal and kinetic energy of the C-P lasers scheme.

  12. Recent Progress in the Negative-Ion-Based Neutral Beam Injectors in Large Helical Device

    Science.gov (United States)

    Takeiri, Y.; Tsumori, K.; Ikeda, K.; Osakabe, M.; Nagaoka, K.; Oka, Y.; Asano, E.; Kondo, T.; Sato, M.; Shibuya, M.; Komada, S.; Kaneko, O.

    2009-03-01

    Negative-ion-based neutral beam injection (negative-NBI) system has been operated for 10 years in Large Helical Device (LHD). The injection power has been increased year by year, according to the improvement of the negative ion sources. Up to now, every injector achieves the designed injection energy and power of 180 keV-5 MW with hydrogen beams, and the total injection power exceeds 16 MW with three injectors. In the multi-round aperture grounded grid (GG), the diameter of a round aperture has been enlarged for higher GG transparency. Then, the GG heat load is reduced, as well as in the multi-slotted GG, and the voltage holding ability in the beam acceleration was improved. As a result, the beam energy is raised and the injection power is increased. To improve the anisotropic property of the beamlet convergence condition between the perpendicular and the parallel directions to the slots in the multi-slotted GG, a round-shape aperture of the steering grid (SG) has been changed to a racetrack shape. As a result, the difference of the beamlet conversion condition is much mitigated, and the injection efficiency (port-transmission efficiency) is improved, leading to 188 keV-6.4 MW injection. The Cs consumption is observed to be proportional to the tungsten evaporation from filaments. The Cs behavior is investigated with optical emission spectroscopy. During the beam extraction, the Cs recycling is dominated by Cs on the backplate, which is evaporated into the plasma by the backstreaming positive ions, and the wall surfaces should be loss regions for the supplied Cs.

  13. A Spectroscopic Study of Impurity Behavior in Neutral-beam and Ohmically Heated TFTR Discharges

    Science.gov (United States)

    Stratton, B. C.; Ramsey, A. T.; Boody, F. P.; Bush, C. E.; Fonck, R. J.; Groenbner, R. J.; Hulse, R. A.; Richards, R. K.; Schivell, J.

    1987-02-01

    Quantitative spectroscopic measurements of Z{sub eff}, impurity densities, and radiated power losses have been made for ohmic- and neutral-beam-heated TFTR discharges at a plasma current of 2.2 MA and toroidal field of 4.7 T. Variations in these quantities with line-average plasma density (anti n{sub e}) and beam power up to 5.6 MW are presented for discharges on a graphite movable limiter. A detailed discussion of the use of an impurity transport model to infer absolute impurity densities and radiative losses from line intensity and visible continuum measurements is given. These discharges were dominated by low-Z impurities with carbon having a considerably higher density than oxygen, except in high-anti n{sub e} ohmic discharges, where the densities of carbon and oxygen were comparable. Metallic impurity concentrations and radiative losses were small, resulting in hollow radiated power profiles and fractions of the input power radiated being 30 to 50% for ohmic heating and 30% or less with beam heating. Spectroscopic estimates of the radiated power were in good agreement with bolometrically measured values. Due to an increase in the carbon density, Z{sub eff} rose from 2.0 to 2.8 as the beam power increased from 0 to 5.6 MW, pointing to a potentially serious dilution of the neutron-producing plasma ions as the beam power increased. Both the low-Z and metallic impurity concentrations were approximately constant with minor radius, indicating no central impurity accumulation in these discharges.

  14. Fast ion confinement and stability in a neutral beam injected reversed field pinch

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, J. K.; Almagri, A. F.; Den Hartog, D. J.; Eilerman, S.; Forest, C. B.; Koliner, J. J.; Mirnov, V. V.; Morton, L. A.; Nornberg, M. D.; Parke, E.; Reusch, J. A.; Sarff, J. S.; Waksman, J. [University of Wisconsin, Madison, Wisconsin 53706 (United States); Belykh, V.; Davydenko, V. I.; Ivanov, A. A.; Polosatkin, S. V.; Tsidulko, Y. A. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation); Lin, L. [University of California, Los Angeles, California 90095 (United States); Liu, D. [University of California, Irvine, California 92697 (United States); and others

    2013-05-15

    The behavior of energetic ions is fundamentally important in the study of fusion plasmas. While well-studied in tokamak, spherical torus, and stellarator plasmas, relatively little is known in reversed field pinch plasmas about the dynamics of fast ions and the effects they cause as a large population. These studies are now underway in the Madison Symmetric Torus with an intense 25 keV, 1 MW hydrogen neutral beam injector (NBI). Measurements of the time-resolved fast ion distribution via a high energy neutral particle analyzer, as well as beam-target neutron flux (when NBI fuel is doped with 3–5% D{sub 2}) both demonstrate that at low concentration the fast ion population is consistent with classical slowing of the fast ions, negligible cross-field transport, and charge exchange as the dominant ion loss mechanism. A significant population of fast ions develops; simulations predict a super-Alfvénic ion density of up to 25% of the electron density with both a significant velocity space gradient and a sharp radial density gradient. There are several effects on the background plasma including enhanced toroidal rotation, electron heating, and an altered current density profile. The abundant fast particles affect the plasma stability. Fast ions at the island of the core-most resonant tearing mode have a stabilizing effect, and up to 60% reduction in the magnetic fluctuation amplitude is observed during NBI. The sharp reduction in amplitude, however, has little effect on the underlying magnetic island structure. Simultaneously, beam driven instabilities are observed as repetitive ∼50 μs bursts which coincide with fast particle redistribution; data indicate a saturated core fast ion density well below purely classical predictions.

  15. Neutron emission in neutral beam heated KSTAR plasmas and its application to neutron radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Jong-Gu, E-mail: jgkwak@nfri.re.kr; Kim, H.S.; Cheon, M.S.; Oh, S.T.; Lee, Y.S.; Terzolo, L.

    2016-11-01

    Highlights: • We measured the neutron emission from KSTAR plasmas quantitatively. • We confirmed that neutron emission is coming from neutral beam-plasma interactions. • The feasibility study shows that the fast neutron from KSTAR could be used for fast neutron radiography. - Abstract: The main mission of Korea Superconducting Tokamak Advanced Research (KSTAR) program is exploring the physics and technologies of high performance steady state Tokamak operation that are essential for ITER and fusion reactor. Since the successful first operation in 2008, the plasma performance is enhanced and duration of H-mode is extended to around 50 s which corresponds to a few times of current diffusion time and surpassing the current conventional Tokamak operation. In addition to long-pulse operation, the operational boundary of the H-mode discharge is further extended over MHD no-wall limit(β{sub N} ∼ 4) transiently and higher stored energy region is obtained by increased total heating power (∼6 MW) and plasma current (I{sub p} up to 1 MA for ∼10 s). Heating system consists of various mixtures (NB, ECH, LHCD, ICRF) but the major horse heating resource is the neutral beam(NB) of 100 keV with 4.5 MW and most of experiments are conducted with NB. So there is a lot of production of fast neutrons coming from via D(d,n){sup 3}He reaction and it is found that most of neutrons are coming from deuterium beam plasma interaction. Nominal neutron yield and the area of beam port is about 10{sup 13}–10{sup 14}/s and 1 m{sup 2} at the closest access position of the sample respectively and neutron emission could be modulated for application to the neutron radiography by varying NB power. This work reports on the results of quantitative analysis of neutron emission measurements and results are discussed in terms of beam-plasma interaction and plasma confinement. It also includes the feasibility study of neutron radiography using KSTAR.

  16. Fabrication study on the cooling module of the ITER neutral beam duct liner

    Energy Technology Data Exchange (ETDEWEB)

    Sa, J.W. [National Fusion Research Institute, Yuseong-gu, Daejeon (Korea, Republic of); Kim, H.S., E-mail: hskim@nfri.re.k [National Fusion Research Institute, Yuseong-gu, Daejeon (Korea, Republic of); Kim, B.Y.; Kim, B.C.; Ahn, H.J.; Bak, J.S. [National Fusion Research Institute, Yuseong-gu, Daejeon (Korea, Republic of); Jung, H.J. [Korean Intellectual Property Office, Seo-gu, Daejeon (Korea, Republic of); Han, M.H.; Hong, C.D.; Lee, J.S.; Kim, Y.K. [Hyundai Heavy Industries Co. Ltd., Dong-gu, Ulsan (Korea, Republic of); Urbani, M. [ITER Organization, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Geli, F. [UKAEA Culham Division, Oxfordshire OX14 3DB, Abingdon (United Kingdom)

    2010-12-15

    Recently the new concept of the ITER neutral beam (NB) duct liner has been developed to improve thermo-mechanical performance and satisfy the requirements for remote handling and maintenance. The design concept of cooling module located inside neutron shield structure is to use deep-drilled panels instead of the original design concept of the casting-modularized component with tubes. In this study, the manufacturing feasibility has been investigated through the fabrication of small size coupons and full scale mock-up. Firstly, the small size coupons are for developing the electron beam welding processes. Secondly, the full scale mock-up which has 6 holes for cooling passage has been fabricated in order to develop the main fabrication processes such as deep drilling, bending and machining. In addition, the pressure and the leak tests have been carried out to check the required performance for completed cooling panel. Although some improvement is required, but the Electron Beam Welding (EBW) has been successfully achieved and generally the deep drilling and bending process also shown good results in dimensional control.

  17. Creation of polarization gradients from superposition of counter propagating vector LG beams.

    Science.gov (United States)

    Vyas, Sunil; Kozawa, Yuichi; Miyamoto, Yoko

    2015-12-28

    We present a detailed theoretical analysis of the formation of standing waves using cylindrically polarized vector Laguerre-Gaussian (LG) beams. It is shown that complex interplay between the radial and azimuthal polarization state can be used to realize different kinds of polarization gradients with cylindrically symmetric polarization distribution. Expressions for four different cases are presented and local dynamics of spatial polarization distribution is studied. We show cylindrically symmetric Sisyphus and corkscrew type polarization gradients can be obtained from vector LG beams. The optical landscape presented here with spatially periodic polarization patterns may find important applications in the field of atom optics, atom interferometry, atom lithography, and optical trapping.

  18. Compact, accurate description of diagnostic neutral beam propagation and attenuation in a high temperature plasma for charge exchange recombination spectroscopy analysis.

    Science.gov (United States)

    Bespamyatnov, Igor O; Rowan, William L; Granetz, Robert S

    2008-10-01

    Charge exchange recombination spectroscopy on Alcator C-Mod relies on the use of the diagnostic neutral beam injector as a source of neutral particles which penetrate deep into the plasma. It employs the emission resulting from the interaction of the beam atoms with fully ionized impurity ions. To interpret the emission from a given point in the plasma as the density of emitting impurity ions, the density of beam atoms must be known. Here, an analysis of beam propagation is described which yields the beam density profile throughout the beam trajectory from the neutral beam injector to the core of the plasma. The analysis includes the effects of beam formation, attenuation in the neutral gas surrounding the plasma, and attenuation in the plasma. In the course of this work, a numerical simulation and an analytical approximation for beam divergence are developed. The description is made sufficiently compact to yield accurate results in a time consistent with between-shot analysis.

  19. The ITER neutral beam test facility: designs of the general infrastructure, cryo-system and cooling plant

    Energy Technology Data Exchange (ETDEWEB)

    Cordier, J.J.; Hemsworth, R.; Chantant, M.; Gravil, B.; Henry, D.; Sabathier, F.; Doceul, L.; Thomas, E.; Van Houtte, D. [Association Euratom-CEA Cadarache (DSM/DRFC), 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Zaccaria, P.; Antoni, V.; Dal Bello, S.; Masiello, A.; Marcuzzi, D. [Consorzio RFX Association Euratom-ENEA, Padova (Italy); Antipenkov, A.; Dremel, M.; Day, C. [Institut fur Technische Physik, FZK, Karlsruhe (Germany); Mondino, P.L. [Max-Planck-Institut fuer Plasmaphysik, EFDA CSU, Garching (Germany)

    2004-07-01

    The CEA Association is involved, in close collaboration with ENEA, FZK, IPP and UKEA European Associations, in the first ITER neutral beam injector and the ITER neutral beam test facility design (NBTF). A total power of about 50 MW will have to be removed in steady state on the neutral beam test facility (NBTF). The main purpose of this task is to make progress with the detailed design of the first ITER NB injector and to start the conceptual design of the ITER NBTF. The general infrastructure layout of a generic site for the NBTF, includes the test facility itself equipped of a dedicated beamline vessel and integration studies of associated auxiliaries as cooling plant, cryo-plant and fore-pumping system. The general infrastructure and auxiliaries layout of the NBTF are described. (authors)

  20. Analysis of the Pipe Heat Loss of the Water Flow Calorimetry System in EAST Neutral Beam Injector

    Science.gov (United States)

    Hu, Chundong; Chen, Yu; Xu, Yongjian; Yu, Ling; Li, Xiang; Zhang, Weitang

    2016-11-01

    Neutral beam injection heating is one of the main auxiliary heating methods in controllable nuclear fusion research. In the EAST neutral beam injector, a water flow calorimetry (WFC) system is applied to measure the heat load on the electrode system of the ion source and the heat loading components of the beamline. Due to the heat loss in the return water pipe, there are some measuring errors for the current WFC system. In this paper, the errors were measured experimentally and analyzed theoretically, which lay a basis for the exact calculation of beam power deposition distribution and neutralization efficiency. supported by the National Magnetic Confinement Fusion Science Program of China (No. 2013GB101001) and the International Science & Technology Cooperation Program of China (No. 2014DFG61950)

  1. Overview of the design of the ITER heating neutral beam injectors

    Science.gov (United States)

    Hemsworth, R. S.; Boilson, D.; Blatchford, P.; Dalla Palma, M.; Chitarin, G.; de Esch, H. P. L.; Geli, F.; Dremel, M.; Graceffa, J.; Marcuzzi, D.; Serianni, G.; Shah, D.; Singh, M.; Urbani, M.; Zaccaria, P.

    2017-02-01

    The heating neutral beam injectors (HNBs) of ITER are designed to deliver 16.7 MW of 1 MeV D0 or 0.87 MeV H0 to the ITER plasma for up to 3600 s. They will be the most powerful neutral beam (NB) injectors ever, delivering higher energy NBs to the plasma in a tokamak for longer than any previous systems have done. The design of the HNBs is based on the acceleration and neutralisation of negative ions as the efficiency of conversion of accelerated positive ions is so low at the required energy that a realistic design is not possible, whereas the neutralisation of H‑ and D‑ remains acceptable (≈56%). The design of a long pulse negative ion based injector is inherently more complicated than that of short pulse positive ion based injectors because: • negative ions are harder to create so that they can be extracted and accelerated from the ion source; • electrons can be co-extracted from the ion source along with the negative ions, and their acceleration must be minimised to maintain an acceptable overall accelerator efficiency; • negative ions are easily lost by collisions with the background gas in the accelerator; • electrons created in the extractor and accelerator can impinge on the extraction and acceleration grids, leading to high power loads on the grids; • positive ions are created in the accelerator by ionisation of the background gas by the accelerated negative ions and the positive ions are back-accelerated into the ion source creating a massive power load to the ion source; • electrons that are co-accelerated with the negative ions can exit the accelerator and deposit power on various downstream beamline components. The design of the ITER HNBs is further complicated because ITER is a nuclear installation which will generate very large fluxes of neutrons and gamma rays. Consequently all the injector components have to survive in that harsh environment. Additionally the beamline components and the NB cell, where the beams are housed, will be

  2. Angular-divergence calculation for Experimental Advanced Superconducting Tokamak neutral beam injection ion source based on spectroscopic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Yuan, E-mail: jtext@hust.edu.cn [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Hu, Chundong [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zhuang, Ge [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-02-15

    Calorimetric method has been primarily applied for several experimental campaigns to determine the angular divergence of high-current ion source for the neutral beam injection system on the Experimental Advanced Superconducting Tokamak (EAST). A Doppler shift spectroscopy has been developed to provide the secondary measurement of the angular divergence to improve the divergence measurement accuracy and for real-time and non-perturbing measurement. The modified calculation model based on the W7AS neutral beam injectors is adopted to accommodate the slot-type accelerating grids used in the EAST's ion source. Preliminary spectroscopic experimental results are presented comparable to the calorimetrically determined value of theoretical calculation.

  3. Modeling and control of plasma rotation for NSTX using neoclassical toroidal viscosity and neutral beam injection

    Energy Technology Data Exchange (ETDEWEB)

    Goumiri, I. R. [Princeton Univ., NJ (United States). Mechanical and Aerospace Dept.; Rowley, C. W. [Princeton Univ., NJ (United States). Mechanical and Aerospace Dept.; Sabbagh, S. A. [Columbia Univ., New York, NY (United States). Dept. of Applied Physics and Applied Mathematics; Gates, D. A. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Gerhardt, S. P. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Boyer, M. D. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Andre, R. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Kolemen, E. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Taira, K. [Florida State Univ, Dept Mech Engn, Tallahassee, FL USA.

    2016-02-19

    A model-based feedback system is presented to control plasma rotation in a magnetically confined toroidal fusion device, to maintain plasma stability for long-pulse operation. This research uses experimental measurements from the National Spherical Torus Experiment (NSTX) and is aimed at controlling plasma rotation using two different types of actuation: momentum from injected neutral beams and neoclassical toroidal viscosity generated by three-dimensional applied magnetic fields. Based on the data-driven model obtained, a feedback controller is designed, and predictive simulations using the TRANSP plasma transport code show that the controller is able to attain desired plasma rotation profiles given practical constraints on the actuators and the available measurements of rotation.

  4. Rare-earth neutral metal injection into an electron beam ion trap plasma

    Energy Technology Data Exchange (ETDEWEB)

    Magee, E. W., E-mail: magee1@llnl.gov; Beiersdorfer, P.; Brown, G. V. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Hell, N. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Dr. Remeis-Sternwarte and ECAP, Universität Erlangen-Nürnberg, 96049 Bamberg (Germany)

    2014-11-15

    We have designed and implemented a neutral metal vapor injector on the SuperEBIT high-energy electron beam ion trap at the Lawrence Livermore National Laboratory. A horizontally directed vapor of a europium metal is created using a thermal evaporation technique. The metal vapor is then spatially collimated prior to injection into the trap. The source's form and quantity constraints are significantly reduced making plasmas out of metal with vapor pressures ≤10{sup −7} Torr at ≥1000 °C more obtainable. A long pulsed or constant feed metal vapor injection method adds new flexibility by varying the timing of injection and rate of material being introduced into the trap.

  5. Ion rotational velocity of a field-reversed configuration plasma measured by neutral beam probe spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Y.; Tanjyo, M.; Ohi, S.; Goto, S.; Ishimura, T.

    1987-01-01

    The ion rotational angular velocity ..cap omega.. and the ion temperature T/sub i/ of a translated field-reversed configuration (FRC) plasma are measured using neutral beam probe spectroscopy. The value of ..cap omega.. is --(1.0--1.2) x ..cap omega..* at the onset time of the n = 2 rotational instability, where ..cap omega..* is the ion diamagnetic frequency for a rigid-rotor equilibrium. The ion rotational direction is the same as the ion diamagnetic direction. The value of ..cap omega.. is smaller than the angular frequency ..omega../sub re/ of the n = 2 instability, which can yield experimental evidence of the ion kinetic effects on the n = 2 instability in the FRC plasma. When the octupole field is applied to the plasma in order to suppress the n = 2 deformation, ..cap omega.. is slightly reduced. The ion temperature T/sub i/ is --70 eV at the onset time of the n = 2 instability.

  6. Insertion of an electron beam ionizer in a quadrupole spectrometer for secondary neutral mass analysis

    CERN Document Server

    Ameziane, O; Serrano, J; Guzman, B; Aguilar, M A

    2003-01-01

    An insertable electron beam ionizer into a quadrupole-based secondary ion mass spectrometer instrument has been designed and installed to analyze sputtered neutrals. The optimum design conditions of the ionizer have been obtained by modeling various configurations of the system using a simulation program developed by us. The program has allowed us to compute the potentials and ion trajectories inside the system to test the performance of the ion optics design. We have investigated the advantages of using a large ionization volume with low electron current to minimize the space charge effect in the ionizer, as this is the major problem in this type of instrument. In addition, we have used the simulations to obtain' all electrodes voltages which provide an efficient suppression of residual gas and secondary ions. A good useful yield was obtained, even with low electron densities, thanks to the high geometrical acceptance of the ionizer and its large active volume. This configuration implies less thermal radiati...

  7. Energy Recovery from a Space-Charge Neutralized Positive Ion Beam by Means of Magnetic Electron Suppression

    Science.gov (United States)

    Ryan, Philip Michael

    The charge-exchange neutralization efficiency of positive ion based neutral beams used in plasma heating applications decreases as the beam energy increases. Direct energy recovery from the charged particles can be accomplished by electrostatically decelerating the positive ions; the problem is to effect this without accelerating the space -charge neutralizing electrons residing in the beam. Prior work with both electrostatic and magnetic electron suppression is reviewed. A finite difference ion optics code which solves the nonlinear Vlasov-Poisson equation is adapted to energy recovery application and used to analyze the transverse magnetic field electron suppression experiments carried out at Oak Ridge National Laboratory between 1980 and 1982. Three numerical models are discussed and evaluated. The double plasma model, which assumes an equilibrium Boltzmann distribution of electrons at both the neutralizer potential and the ion collector potential, most successfully duplicates the experimental results with beams in the 40 keV, 10 A range. It is used to analyze the effects of the magnetic field strength, the ion "boost" energy, and the ion beam current density on the ion collection efficiency. Conclusions of the study are: (1) the electron leakage current scales as B('-1), necessitating magnetic suppression fields in excess of 0.1 tesla; (2) the neutralizer geometry should provide an electrostatic field to counteract the magnetic force on the ions; (3) fractional energy beam ions should be confined to the neutralizer interior; (4) the neutral line density in the recovery region should be less than 3 x 10('-3) torr(.)cm. Recovery efficiency decreases with increasing beam current density; a net recovery efficiency of 30% (ion collection efficiency of 75%) at 5 mA/cm('2) falls to zero at 10 mA/cm('2) for a 40 keV beam. New designs are presented and analyzed: an ion collection efficiency of close to 90% is predicted for an 80 keV D ion beam with an ion current

  8. Fishbone activity in experimental advanced superconducting tokamak neutral beam injection plasma

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Liqing; Zhang, Jizong; Chen, Kaiyun, E-mail: Kychen@ipp.cas.cn, E-mail: lqhu@ipp.cas.cn; Hu, Liqun, E-mail: Kychen@ipp.cas.cn, E-mail: lqhu@ipp.cas.cn; Li, Erzhong; Lin, Shiyao; Shi, Tonghui; Duan, Yanmin [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zhu, Yubao [Department of Physics and Astronomy, University of California, Irvine, California 92697-4575 (United States)

    2015-12-15

    Repetitive fishbones near the trapped ion procession frequency were observed for the first time in the neutral beam injection high confinement plasmas in Experimental Advanced Superconducting Tokamak (EAST) tokamak, and diagnosed using a solid-state neutral particle analyzer based on a compact silicon photodiode together with an upgraded high spatial-temporal-resolution multi-arrays soft X-ray (SX) system. This 1/1 typical internal kink mode propagates in the ion-diamagnetism direction with a rotation speed faster than the bulk plasma in the plasma frame. From the SX measurements, this mode frequency is typical of chirping down and the energetic particle effect related to the twisting mode structure. This ion fishbone was found able to trigger a multiple core sawtooth crashes with edge-2/1 sideband modes, as well as to lead to a transition from fishbone to long lived saturated kink mode to fishbone. Furthermore, using SX tomography, a correlation between mode amplitude and mode frequency was found. Finally, a phenomenological prey–predator model was found to reproduce the fishbone nonlinear process well.

  9. A review of JET neutral beam system performance 1994-2003

    Energy Technology Data Exchange (ETDEWEB)

    King, Robert [UKAEA/EURATOM Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom)]. E-mail: robert.king@jet.uk; Challis, Clive [UKAEA/EURATOM Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Ciric, Dragoslav [UKAEA/EURATOM Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom)

    2005-11-15

    The operational performance of the JET neutral beam injector (NBI) system during 2003 is presented and compared with NBI operation from 1994 to 2002. The paper also addresses different demands imposed on NBI operation during the JET Joint Undertaking (until the end of 1999) and the European Fusion Development Agreement (EFDA) JET operating contract (from 2000). The material presented shows new operational performance records achieved in 2003, derived from data focused on average and maximum pulse lengths, pulse power and injected pulse energy. Over the last 10 years, the issue of JET NBI positive ion neutral injector (PINI) reliability and availability has also been of significant interest. A discussion is presented where terminology is defined, technical systems causing unreliability and non-availability are analysed and operational practices are reviewed. The performance analysis shows that during the period of JET operation under the EFDA contract, the NBI facility has successfully changed from high power-short pulse to high power-long pulse (10 s) operation. It also shows that the sources of unreliability and non-availability have largely remained constant during this change.

  10. A simulation study of interactions of space-shuttle generated electron beams with ambient plasma and neutral gas

    Science.gov (United States)

    Winglee, Robert M.

    1991-01-01

    The objective was to conduct large scale simulations of electron beams injected into space. The study of the active injection of electron beams from spacecraft is important, as it provides valuable insight into the plasma beam interactions and the development of current systems in the ionosphere. However, the beam injection itself is not simple, being constrained by the ability of the spacecraft to draw current from the ambient plasma. The generation of these return currents is dependent on several factors, including the density of the ambient plasma relative to the beam density, the presence of neutrals around the spacecraft, the configuration of the spacecraft, and the motion of the spacecraft through the plasma. Two dimensional (three velocity) particle simulations with collisional processes included are used to show how these different and often coupled processes can be used to enhance beam propagation from the spacecraft. To understand the radial expansion mechanism of an electron beam injected from a highly charged spacecraft, two dimensional particle-in-cell simulations were conducted for a high density electron beam injected parallel to magnetic fields from an isolated equipotential conductor into a cold background plasma. The simulations indicate that charge build-up at the beam stagnation point causes the beam to expand radially to the beam electron gyroradius.

  11. Progress in the realization of the PRIMA neutral beam test facility

    Science.gov (United States)

    Toigo, V.; Boilson, D.; Bonicelli, T.; Piovan, R.; Hanada, M.; Chakraborty, A.; Agarici, G.; Antoni, V.; Baruah, U.; Bigi, M.; Chitarin, G.; Dal Bello, S.; Decamps, H.; Graceffa, J.; Kashiwagi, M.; Hemsworth, R.; Luchetta, A.; Marcuzzi, D.; Masiello, A.; Paolucci, F.; Pasqualotto, R.; Patel, H.; Pomaro, N.; Rotti, C.; Serianni, G.; Simon, M.; Singh, M.; Singh, N. P.; Svensson, L.; Tobari, H.; Watanabe, K.; Zaccaria, P.; Agostinetti, P.; Agostini, M.; Andreani, R.; Aprile, D.; Bandyopadhyay, M.; Barbisan, M.; Battistella, M.; Bettini, P.; Blatchford, P.; Boldrin, M.; Bonomo, F.; Bragulat, E.; Brombin, M.; Cavenago, M.; Chuilon, B.; Coniglio, A.; Croci, G.; Dalla Palma, M.; D'Arienzo, M.; Dave, R.; De Esch, H. P. L.; De Lorenzi, A.; De Muri, M.; Delogu, R.; Dhola, H.; Fantz, U.; Fellin, F.; Fellin, L.; Ferro, A.; Fiorentin, A.; Fonnesu, N.; Franzen, P.; Fröschle, M.; Gaio, E.; Gambetta, G.; Gomez, G.; Gnesotto, F.; Gorini, G.; Grando, L.; Gupta, V.; Gutierrez, D.; Hanke, S.; Hardie, C.; Heinemann, B.; Kojima, A.; Kraus, W.; Maeshima, T.; Maistrello, A.; Manduchi, G.; Marconato, N.; Mico, G.; Moreno, J. F.; Moresco, M.; Muraro, A.; Muvvala, V.; Nocentini, R.; Ocello, E.; Ochoa, S.; Parmar, D.; Patel, A.; Pavei, M.; Peruzzo, S.; Pilan, N.; Pilard, V.; Recchia, M.; Riedl, R.; Rizzolo, A.; Roopesh, G.; Rostagni, G.; Sandri, S.; Sartori, E.; Sonato, P.; Sottocornola, A.; Spagnolo, S.; Spolaore, M.; Taliercio, C.; Tardocchi, M.; Thakkar, A.; Umeda, N.; Valente, M.; Veltri, P.; Yadav, A.; Yamanaka, H.; Zamengo, A.; Zaniol, B.; Zanotto, L.; Zaupa, M.

    2015-08-01

    The ITER project requires additional heating by two neutral beam injectors, each accelerating to 1 MV a 40 A beam of negative deuterium ions, to deliver to the plasma a power of about 17 MW for one hour. As these requirements have never been experimentally met, it was recognized as necessary to setup a test facility, PRIMA (Padova Research on ITER Megavolt Accelerator), in Italy, including a full-size negative ion source, SPIDER, and a prototype of the whole ITER injector, MITICA, aiming to develop the heating injectors to be installed in ITER. This realization is made with the main contribution of the European Union, through the Joint Undertaking for ITER (F4E), the ITER Organization and Consorzio RFX which hosts the Test Facility. The Japanese and the Indian ITER Domestic Agencies (JADA and INDA) participate in the PRIMA enterprise; European laboratories, such as IPP-Garching, KIT-Karlsruhe, CCFE-Culham, CEA-Cadarache and others are also cooperating. Presently, the assembly of SPIDER is on-going and the MITICA design is being completed. The paper gives a general overview of the test facility and of the status of development of the MITICA and SPIDER main components at this important stage of the overall development; then it focuses on the latest and most critical issues, regarding both physics and technology, describing the identified solutions.

  12. Conceptual design of a compact absolute valve for the ITER neutral beam injectors

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Chris [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)], E-mail: chris.m.jones@jet.uk; Waldon, Chris; Martin, David; Watson, Mike [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Sonderegger, Kurt; Lenherr, Bruno [VAT Vakuumventile AG, CH-9469 Haag (Switzerland); Andrews, Ian; Mansbridge, Simon [VAT Vacuum Products Ltd., Edmund House, Rugby Road, Leamington Spa, Warwickshire CV32 6EL (United Kingdom)

    2009-06-15

    The reference design for the ITER neutral beam injectors incorporated a fast shutter to limit tritium migration to the injector vacuum enclosures. In 2005, a need for an 'absolute' isolation valve was identified to facilitate injector maintenance procedures and protect the system from an in-vessel ingress of coolant event (ICE). An outline concept for an all-metal seal valve was developed during 2006, in close cooperation with the Swiss valve manufacturer VAT. During the following year, it became apparent that the length of beamline available for the valve was significantly less than originally envisaged, resulting in a radical revision of the design concept. A casing length of 760 mm has been achieved by means of major changes to the casing structure, plate dimensions, pendulum mechanism and seal actuators. A concept for a seal protection system has been developed to prevent beam line contamination reaching the valve components and to protect the valve plate from surface heating by plasma radiation. The new design concept has been extensively validated by analysis, including a whole-system FE model of the valve.

  13. Design of the Prototype Negative Ion Source for Neutral Beam Injector at ASIPP

    Science.gov (United States)

    Wei, Jianglong; Xie, Yahong; Liang, Lizhen; Gu, Yuming; Yi, Wei; Li, Jun; Hu, Chundong; Xie, Yuanlai; Jiang, Caichao; Tao, Ling; Sheng, Peng; Xu, Yongjian

    2016-09-01

    In order to support the design, manufacture and commissioning of the negative-ion-based neutral beam injection (NBI) system for the Chinese Fusion Engineering Test Reactor (CFETR), the Hefei utility negative ion test equipment with RF source (HUNTER) was proposed at ASIPP. A prototype negative ion source will be developed at first. The main bodies of plasma source and accelerator of the prototype negative ion source are similar to that of the ion source for EAST-NBI. But instead of the filament-arc driver, an RF driver is adopted for the prototype negative ion source to fulfill the requirement of long pulse operation. A cesium seeding system and a magnetic filter are added for enhancing the negative ion density near the plasma grid and minimizing co-extracted electrons. Besides, an ITER-like extraction system is applied inside the accelerator, where the negative ion beam is extracted and accelerated up to 50 kV. supported by National Natural Science Foundation of China (Nos. 11505224, 11575240, 11405207), the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB101001, 2013GB101002, 2013GB101003), International Science and Technology Cooperation Program of China (No. 2014DFG61950), and Foundation of ASIPP (No. DSJJ-14-JC07)

  14. Counter-intuitive quasi-periodic motion in the autonomous vibration of cracked Timoshenko beams

    Science.gov (United States)

    Brandon, J. A.; Abraham, O. N. L.

    1995-08-01

    The time domain behaviour of a cracked Timoshenko beam is constructed by alternation of two linear models corresponding to the open and closed condition of the crack. It might be expected that a response which is composed of the alternation of two systems with different properties would extinguish the periodicities of the constituent sub-models. The numerical studies presented illustrate the perpetuation of these features without showing any evidence for the creation of periodicities based on a common assumption of the mean period of a bilinear model.

  15. Neutral beam excitation of Alfven continua in the madison symmetric torus reversed field pinch

    Science.gov (United States)

    Koliner, Jonathan Jay

    Alfven continua and Alfven eigenmodes (AEs) have been generated for reversed-field pinch (RFP) plasma equilibria in Madison Symmetric Torus (MST). Data gathered from the extensive suite of diagnostics on MST was used to generate equilibria using MSTFIT and VMEC. Three dimensional equilibria for spontaneous helical states were generated using the equilibrium reconstruction code V3FIT. The reduced-MHD codes AE3D and STELLGAP were run on all generated equilibria to calculate the continua and AEs. All continuum solutions contain a toroidicity-induced Alfven gap at 200-400 kHz, within which AE solutions appear by coupling of m=0,1 at medium n. The first observation of beam-driven instabilities on the RFP was performed using MST magnetics during neutral beam injection (NBI). Spatially coherent bursts with n=5,m=1 were observed in plasmas with edge safety factor q_a=0. The bursts oscillate at 65 kHz, and reach maximum amplitude and decay away within 100 mus. These bursts persist for the duration of NBI. Secondary n=-1 and n=4 bursts are coupled in time, reaching maximum amplitude with 50 mus after the n=5 peak amplitude. While the n=5 bursts scale weakly with the electron density n_e and strongly with the beam velocity v_beam, the n=4 bursts scale with the Alfven speed v_A. The burst frequencies are well below those of the calculated AEs and the modes are driven even with v_ beam plasmas. In reversed plasmas, the temporally changing q profile changes the burst resonances, bringing n=6 into resonance halfway through the sawtooth cycle. The n=5 mode switches from its frequency in non-reversed plasmas to a higher frequency at the end of the sawtooth cycle. In deeply reversed plasmas, the bursts are weaker and display chirping behavior as the plasma reversal increases. During the transition to a helical state, the bursts increase in frequency as q on-axis changes, altering the parallel wavenumber k_||. When the helical state is established, the bursts terminate.

  16. Countering beam divergence effects with focused segmented scintillators for high DQE megavoltage active matrix imagers

    Science.gov (United States)

    Liu, Langechuan; Antonuk, Larry E.; Zhao, Qihua; El-Mohri, Youcef; Jiang, Hao

    2012-08-01

    The imaging performance of active matrix flat-panel imagers designed for megavoltage imaging (MV AMFPIs) is severely constrained by relatively low x-ray detection efficiency, which leads to a detective quantum efficiency (DQE) of only ∼1%. Previous theoretical and empirical studies by our group have demonstrated the potential for addressing this constraint through the utilization of thick, two-dimensional, segmented scintillators with optically isolated crystals. However, this strategy is constrained by the degradation of high-frequency DQE resulting from spatial resolution loss at locations away from the central beam axis due to oblique incidence of radiation. To address this challenge, segmented scintillators constructed so that the crystals are individually focused toward the radiation source are proposed and theoretically investigated. The study was performed using Monte Carlo simulations of radiation transport to examine the modulation transfer function and DQE of focused segmented scintillators with thicknesses ranging from 5 to 60 mm. The results demonstrate that, independent of scintillator thickness, the introduction of focusing largely restores spatial resolution and DQE performance otherwise lost in thick, unfocused segmented scintillators. For the case of a 60 mm thick BGO scintillator and at a location 20 cm off the central beam axis, use of focusing improves DQE by up to a factor of ∼130 at non-zero spatial frequencies. The results also indicate relatively robust tolerance of such scintillators to positional displacements, of up to 10 cm in the source-to-detector direction and 2 cm in the lateral direction, from their optimal focusing position, which could potentially enhance practical clinical use of focused segmented scintillators in MV AMFPIs.

  17. Comparison of methods to measure the rate of neutral free radical production by photo-deionization of negative ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Keiji E-mail: khayashi@neptune.kanazawa-it.ac.jp; Konno, Hiroshi; Oseki, Takashi; Kojima, Hideki; Kanayama, Takuo

    2003-05-01

    Two measurement methods to determine the rate of neutral free radical production by the photo-deionization of negative ion beams (PDINIB) are introduced. These methods, namely, photoelectron-current measurement by low-frequency electro-modulation probe (PMMP) and measurement of decrease in the negative-ion beam current (DNIC) were employed to evaluate the production rate in a trial surface-processing apparatus developed in the author's laboratory utilizing a steady-flux refined beam of neutral free radicals (RBNR) produced by the PDINIB procedure. A {sup 63}Cu{sup -} negative ion beam of kinetic energy E{sub i} varied up to 15 keV was irradiated with a 514.5 nm visible light beam from a 25 W CW Ar{sup +} ion laser. The detection limit of the production rate by the PMMP setup was as high as 6 x 10{sup 9} s{sup -1} under the condition that E{sub i}=15 keV, the negative-ion beam current I{sub i}=4 {mu}A and the laser power P=6 W. The DNIC method is simpler but less reliable than the PMMP method owing to larger uncertainty resulting from the fluctuation of the negative-ion beam current.

  18. Powerloads on the front end components and the duct of the heating and diagnostic neutral beam lines at ITER

    Energy Technology Data Exchange (ETDEWEB)

    Singh, M. J.; Boilson, D.; Hemsworth, R. S.; Geli, F.; Graceffa, J.; Urbani, M.; Schunke, B.; Chareyre, J. [ITER Organisation, 13607 St. Paul-Lez-Durance Cedex (France); Dlougach, E.; Krylov, A. [RRC Kurchatov institute, 1, Kurchatov Sq, Moscow, 123182 (Russian Federation)

    2015-04-08

    The heating and current drive beam lines (HNB) at ITER are expected to deliver ∼16.7 MW power per beam line for H beams at 870 keV and D beams at 1 MeV during the H-He and the DD/DT phases of ITER operation respectively. On the other hand the diagnostic neutral beam (DNB) line shall deliver ∼2 MW power for H beams at 100 keV during both the phases. The path lengths over which the beams from the HNB and DNB beam lines need to be transported are 25.6 m and 20.7 m respectively. The transport of the beams over these path lengths results in beam losses, mainly by the direct interception of the beam with the beam line components and reionisation. The lost power is deposited on the surfaces of the various components of the beam line. In order to ensure the survival of these components over the operational life time of ITER, it is important to determine to the best possible extent the operational power loads and power densities on the various surfaces which are impacted by the beam in one way or the other during its transport. The main factors contributing to these are the divergence of the beamlets and the halo fraction in the beam, the beam aiming, the horizontal and vertical misalignment of the beam, and the gas profile along the beam path, which determines the re-ionisation loss, and the re-ionisation cross sections. The estimations have been made using a combination of the modified version of the Monte Carlo Gas Flow code (MCGF) and the BTR code. The MCGF is used to determine the gas profile in the beam line and takes into account the active gas feed into the ion source and neutraliser, the HNB-DNB cross over, the gas entering the beamline from the ITER machine, the additional gas atoms generated in the beam line due to impacting ions and the pumping speed of the cryopumps. The BTR code has been used to obtain the power loads and the power densities on the various surfaces of the front end components and the duct modules for different scenarios of ITER

  19. Modeling the response of a fast ion loss detector using orbit tracing techniques in a neutral beam prompt-loss study on the DIII-D tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Pace, D. C.; Heidbrink, W. W.; Muscatello, C. M.; Zhu, Y. B. [University of California-Irvine, Irvine, California 92697 (United States); Fisher, R. K.; Van Zeeland, M. A. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Garcia-Munoz, M. [Max-Planck-Institut fuer Plasmaphysik, Garching D-85748 (Germany); Darrow, D. S.; Nazikian, R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451 (United States)

    2010-10-15

    A numerical model describing the expected measurements of neutral beam prompt-losses by a newly commissioned fast ion loss detector (FILD) in DIII-D is presented. This model incorporates the well understood neutral beam deposition profiles from all eight DIII-D beamlines to construct a prompt-loss source distribution. The full range of detectable ion orbit phase space available to the FILD is used to calculate ion trajectories that overlap with neutral beam injection footprints. Weight functions are applied to account for the level of overlap between these detectable orbits and the spatial and velocity (pitch) properties of ionized beam neutrals. An experimental comparison is performed by firing each neutral beam individually in the presence of a ramping plasma current. Fast ion losses determined from the model are in agreement with measured losses.

  20. 3D characterization of the forces in optical traps based on counter-propagation beams shaped by a spatial light modulator

    DEFF Research Database (Denmark)

    Kristensen, M. V.; Lindballe, T.; Kylling, A.

    2010-01-01

    An experimental characterization of the 3D forces, acting on a trapped polystyrene bead in a counter-propagating beam geometry, is reported. Using a single optical trap with a large working distance (in the BioPhotonics Workstation), we simultaneously measure the transverse and longitudinal trapp...... power of 2x35 mW) for displacements in opposite directions. The Equipartition method is limited by mechanical noise and is shown to be applicable only when the total laser power in a single 10 µm counter-propagating trap is below 2x20 mW....... trapping force constants. Two different methods were used: The Drag force method and the Equipartition method. We show that the counterpropagating beams traps are simple harmonic for small displacements. The force constants reveal a transverse asymmetry as - = 9.7 pN/µm and + = 11.3 pN/µm (at a total laser...

  1. EPOCH code simulation of a non-thermal distribution driven by neutral beam injection in a high-beta plasma

    Science.gov (United States)

    Necas, A.; Tajima, T.; Nicks, S.; Magee, R.; Clary, R.; Roche, T.; Tri Alpha Energy Team

    2016-10-01

    In Tri Alpha Energy's C-2U experiment, advanced beam-driven field-reversed configuration (FRC) plasmas were sustained via tangential neutral beam injection. The dominant fast ion population made a dramatic impact on the overall plasma performance. To explain an experimentally observed anomalous neutron signal (100x thermonuclear), we use EPOCH PIC code to simulate possible beam driven non-destructive instabilities that transfer energy from fast ions to the plasma, causing phase space bunching. We propose that the hydrogen beam ion population drives collective modes in the deuterium target plasma, giving rise to the instability and increased fusion rate. The instability changes character from electrostatic in the low beta edge to fully electromagnetic in the core, with an associated reduction in growth rates. The DD reactivity enhancement is calculated using a two-body correlation function and compared to the experimentally observed neutron yield. The high-energy tails in the distributions of the plasma deuterons and beam protons are observed via a mass-resolving Neutral Particle Analyzer (NPA) diagnostic. This observation is qualitatively consistent with EPOCH simulation of the beam-plasma instability.

  2. Comparison of fast ion confinement during on-axis and off-axis neutral beam experiments on NSTX-U

    Science.gov (United States)

    Liu, D.; Heidbrink, W. W.; Hao, G. Z.; Podesta, M.; Darrow, D. S.; Fredrickson, E. D.; Medley, S. S.

    2015-11-01

    A second and more tangential neutral beam line is a major upgrade component of the National Spherical Torus Experiment - Upgrade (NSTX-U) with the purpose of improving neutral beam current drive efficiency and providing more flexibility in current/pressure profile control. Good fast ion confinement is essential to achieve the anticipated improvements in performance. In a planed ``sanity check'' experiment, various short and long (relative to fast ion slowing-down time) neutral beam (NB) pulses with different source mixes will be injected into quiescent L-mode plasmas to characterize the fast ion confinement and distribution function produced by the new and the existing NBI lines. The neutron rate decay after the turn-off of short NB pulses will be used to estimate the fast ion confinement time and to investigate its dependence on NB source/geometry, injection energy, and plasma current. The newly installed Solid State Neutral Particle Analyzer (SSNPA) and Fast-Ion D-Alapha (FIDA) diagnostics will be described and will be used to measure fast ion slowing-down distribution function and spatial profile during the injection of relatively long NB pulses. Fast ion prompt losses will be monitored with a scintillator Fast Lost Ion Probe (sFLIP) diagnostic. The experimental techniques, measurements of fast ion confinement time and distribution function, and comparisons with classical predictions from NUBEAM modeling will be presented in detail. Work supported by US DOE.

  3. Inclined slot-excited annular electron cyclotron resonance plasma source for hyperthermal neutral beam generation.

    Science.gov (United States)

    You, H-J; Kim, D-W; Koo, M; Jang, S-O; Jung, Y-H; Hong, S-H; Lee, B-J

    2011-01-01

    An inclined slot-excited antenna (ISLAN) electron cyclotron resonance (ECR) plasma source is newly designed and constructed for higher flux hyperthermal neutral beam (HNB) generation. The developed ISLAN source is modified from vertical slot-excited antenna (VSLAN) source in two aspects: one is the use of inclined slots instead of vertical slots, and the other is a cusp magnetic field configuration rather than a toroidal configuration. Such modifications allow us to have more uniform arrangement of slots and magnets, then enabling plasma generation more uniform and thinner. Moreover, ECR plasma allows higher ionization rate, enabling plasma density higher even in submillitorr pressures, therefore decreasing the collision rate and∕or the reionization rate of the reflected atoms while passing through the plasma, and eventually getting higher flux of HNBs. In this paper, we report the design features and the plasma characteristics of the ISLAN source by doing plasma measurements and electromagnetic simulations. It was found that ISLAN source can be a high potential source for larger flux HNB generation; the source was found to give higher plasma densities and better uniformities than inductively coupled plasma source, particularly in low pressure ranges. Also, it is important that using ISLAN gives easier matching and better stability, i.e., ISLAN shows similar field patterns and good plasma symmetries irrespective of the variations of the mean diameter of the ring resonator and∕or the presence of a limiter or a reflector, and the operating pressures.

  4. Development of Distributed Control System for Neutral Beam Injector on EAST

    Science.gov (United States)

    Sheng, Peng; Hu, Chundong; Cui, Qinglong; Zhao, Yuanzhe; Zhang, Xiaodan; Zhang, Rui; Lin, Yulian; Yu, Shan; Gao, Yangyang

    2015-07-01

    A distributed control system of Neutral Beam Injector (NBI) on the Experimental Advanced Superconducting Tokamak (EAST-NBI) is briefly presented in this paper. The control system is developed in accordance with the experimental operational characteristics of the EAST-NBI. The NBI control system (NBICS), which is based on the computer network technologies and classified according to the control levels, consists of three levels: a remote monitoring layer, a server control layer, and a field control layer. The 3-layer architecture is capable of extending the system functions and upgrading devices. The timing system provides the reference clock of the synchronization and interlock for the EAST-NBI system. An interlock system ensures the safety of the experiment operators and field devices. Both of the ion sources of the beamline are designed to operate independently. This lays an important foundation for developing a control system for the second beamline on EAST. Experimental results demonstrate that the NBICS meets functional requirements of the EAST-NBI control, and makes experimental operations visual and automatic. supported by the National Magnetic Confinement Fusion Science Program of China (No. 2013GB101001)

  5. Modelling and shielding analysis of the neutral beam injector ports in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Pereslavtsev, P., E-mail: pavel.pereslavtsev@kit.edu [Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Fischer, U. [Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Loughlin, M. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Lu, Lei [Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Polunovskiy, E. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Vielhaber, S. [Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2015-10-15

    Highlights: • The engineering CAD models of the NBI ports were simplified on the CATIA platform. • CAD to MCNP model convesion was done making use of McCAD converting tool. • The new NBI port model was integrated into 80° A-lite ITER torus sector model. • The nuclear responces important for the safety issues were assessed. - Abstract: A new MCNP geometry model of the ITER Neutral Beam Injection (NBI) ports was developed starting from the latest engineering CAD models provided by ITER. The model includes 3 heating (HNBI) ports and one diagnostic port (DNBI), and extends up to the bio-shield. The engineering CAD models were simplified on the CATIA platform according to the neutronic requirements and then converted into MCNP geometry making use of the McCad conversion tool. Finally, the new NBI port model was integrated into an available 80° A-lite ITER torus sector model. The nuclear analysis performed on the basis of this model provides the following nuclear responses: the neutron flux distribution in all NBI ports, the nuclear heating distribution in all NBI ducts; the nuclear heating and radiation loads to the TFC magnets; the radiation damage and gas production in the VV; and the distribution of the shutdown dose rate inside the cryostat.

  6. SYSTEM DESIGN AND PERFORMANCE FOR THE RECENT DIII-D NEUTRAL BEAM COMPUTER UPGRADE

    Energy Technology Data Exchange (ETDEWEB)

    PHILLIPS,J.C; PENAFLOR,B.G; PHAM,N.Q; PIGLOWSKI,D.A

    2003-10-01

    OAK-B135 This operating year marks an upgrade to the computer system charged with control and data acquisition for neutral beam injection system's heating at the DIII-D National Fusion Facility, funded by the US Department of Energy and operated by General Atomics (GA). This upgrade represents the third and latest major revision to a system which has been in service over twenty years. The first control and data acquisition computers were four 16 bit mini computers running a proprietary operating system. Each of the four controlled two ion source over dedicated CAMAC highway. In a 1995 upgrade, the system evolved to be two 32 bit Motorola mini-computers running a version of UNIX. Each computer controlled four ion sources with two CAMAC highways per CPU. This latest upgrade builds on this same logical organization, but makes significant advances in cost, maintainability, and the degree to which the system is open to future modification. The new control and data acquisition system is formed of two 2 GHz Intel Pentium 4 based PC's, running the LINUX operating system. Each PC drives two CAMAC serial highways using a combination of Kinetic Systems PCI standard CAMAC Hardware Drivers and a low-level software driver written in-house expressly for this device. This paper discusses the overall system design and implementation detail, describing actual operating experience for the initial six months of operation.

  7. Neutral beam injection in a D-{sup 3}He FRC reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, Hugo; Farengo, Ricardo [Centro Atomico Bariloche (CNEA) and Instituto Balseiro (UNC-CNEA) 8400 S. C. de Bariloche, RN (Argentina)

    2007-06-15

    The use of neutral beam injection (NBI) to sustain a fraction of the plasma current in a field reversed configuration (FRC) reactor operating with the D-{sup 3}He reaction is studied. A Monte Carlo code already used to study NBI in medium size FRCs is employed (Lifschitz A F, Farengo R and Arista N R 2002 Nucl. Fusion 42 863, Lifschitz A F, Farengo R and Arista N R 2002 Plasma Phys. Control. Fusion 44 1979, Lifschitz A F, Farengo R and Hoffman A L 2004 Nucl. Fusion 44 1015) and the plasma parameters are similar to those proposed in the ARTEMIS (Momota H, Ishida A, Kohzaki Y, Miley G, Ohi S, Ohnishi M, Sato K, Steinhauer L, Tomita Y and Tuszewki M 1992 Fusion Technol. 21 2307) conceptual reactor design. A simple analysis shows that the driven current cannot reach the values quoted in the ARTEMIS project and a procedure to search for plasma parameters that result in higher efficiencies is presented.

  8. High heat flux engineering for the upgraded neutral beam injection systems of MAST-U

    Energy Technology Data Exchange (ETDEWEB)

    Dhalla, F., E-mail: Fahim.dhalla@ccfe.ac.uk; Mistry, S.; Turner, I.; Barrett, T.R.; Day, I.; McAdams, R.

    2015-10-15

    Highlights: • A new Residual Ion Dump (RID) and bend magnet system for the upgraded NBI systems have been designed for the 5 s MAST-U pulse requirements. • Design scoping was performed using numerical ion-tracing analysis software (MAGNET and OPERA codes). • A more powerful bending magnet will separate the residual ions into full, half and third energy components. • Three separate CuCrZr dumps spread the power loading resulting in acceptable power footprints. • FE thermo-mechanical analyses using ANSYS to validate the designs against the ITER SDC-IC code. • New bend magnet coils, yoke and CuCrZr water-cooled plates are in the procurement phase. - Abstract: For the initial phase of MAST-U operation the two existing neutral beam injection systems will be used, but must be substantially upgraded to fulfil expected operational requirements. The major elements are the design, manufacture and installation of a bespoke bending magnet and Residual Ion Dump (RID) system. The MAST-design full energy dump is being replaced with new actively-cooled full, half and third energy dumps, designed to receive 2.4 MW of ion power deflected by an iron-cored electromagnet. The main design challenge is limited space available in the vacuum vessel, requiring ion-deflection calculations to ensure acceptable heat flux distribution on the dump panels. This paper presents engineering and physics analysis of the upgraded MAST beamlines and reports the current status of manufacture.

  9. Discrimination of charged particles in a neutral beam line by using a solid scintillation detector

    Science.gov (United States)

    Woo, Jong-Kwan; Ko, Jewou; Liu, Dong

    2017-01-01

    In the past several decades, many studies have been conducted to search for non-baryonic dark matter, such as weakly interactive massive particles (WIMPs). In the search for WIMPs, charged particles incident on the detector are background particles because WIMPs are neutral. Charged particles originate from various sources, such as cosmic rays and laboratory materials surrounding the main detector. Therefore, a veto that discriminates charged particles can improve the particle-detection efficiency of the entire experiment for detecting WIMPs. Here, we investigate in the thickness range of 1 mm to 5 mm, the optimal thickness of a polystyrene scintillator as a chargedparticle veto detector. We found that 3-mm-thick polystyrene provides the best performance to veto charged particles and the charged-particle background in the search for the WIMP signal. Furthermore, we fabricated 3-mm-thick and 5-mm-thick polystyrene charged particle veto detectors that will be used in an underground laboratory in the search for WIMP dark matter. After exposing those detectors are the actual beam line, we compared the rate of charged particles measured using those detectors and the rate simulated through a Monte Carlo simulation.

  10. The first CEDAR counter

    CERN Multimedia

    1976-01-01

    The first differential Cerenkov counter with chromatic corrections (called CEDAR) successfully tested at the PS in July 75. These counters were used in the SPS hadronic beams for particle identification. Some of the eight photomultipliers can be seen: they receive the light reflected back through the annular diaphragm. René Maleyran stands on the left.

  11. Manufacturing of the full size prototype of the ion source for the ITER neutral beam injector – The SPIDER beam source

    Energy Technology Data Exchange (ETDEWEB)

    Pavei, Mauro, E-mail: mauro.pavei@igi.cnr.it [Consorzio RFX, C.so Stati Uniti 4, I-35127, Padova (Italy); Boilson, Deirdre [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Bonicelli, Tullio [Fusion for Energy, C/Joseph Pla 2, 08019 Barcelona (Spain); Boury, Jacques [Thales Electron Devices, Velizy Villacoublay (France); Bush, Michael [Galvano-T GmbH, T, Raiffeisenstraße 8, 51570 Windeck (Germany); Ceracchi, Andrea; Faso, Diego [CECOM S.r.l., Via Tiburtina – Guidonia Montecelio, Roma (Italy); Graceffa, Joseph [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Heinemann, Bernd [Max-Planck-Institut für Plasmaphysik, D-85740 Garching (Germany); Hemsworth, Ronald [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Lievin, Christophe [Thales Electron Devices, Velizy Villacoublay (France); Marcuzzi, Diego [Consorzio RFX, C.so Stati Uniti 4, I-35127, Padova (Italy); Masiello, Antonio [Fusion for Energy, C/Joseph Pla 2, 08019 Barcelona (Spain); Sczepaniak, Bernd [Galvano-T GmbH, T, Raiffeisenstraße 8, 51570 Windeck (Germany); Singh, Mahendrajit [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Toigo, Vanni; Zaccaria, Pierluigi [Consorzio RFX, C.so Stati Uniti 4, I-35127, Padova (Italy)

    2015-10-15

    Highlights: • Negative ion sources are key components of neutral beam injectors for nuclear fusion. • The SPIDER experiment aims to optimize the negative ion source of MITICA and HNB. • The SPIDER Beam Source manufacturing is currently on-going. • Manufacturing and assembling technological issues encountered are presented. - Abstract: In ITER, each heating neutral beam injector (HNB) will deliver about 16.5 MW heating power by accelerating a 40 A deuterium negative ion beam up to the energy of 1 MeV. The ions are generated inside a caesiated negative ion source, where the injected H{sub 2}/D{sub 2} is ionized by a radio frequency electromagnetic field. The SPIDER test bed, currently being manufactured, is going to be the ion source test facility for the full size ion source of the HNBs and of the diagnostic neutral beam injector of ITER. The SPIDER beam source comprises an ion source with 8 radio-frequency drivers and a three-grid system, providing an overall acceleration up to energies of about 100 keV [1]. SPIDER represents a substantial step forward between the half ITER size ion source, which is currently being tested at the ELISE test bed in IPP-Garching, and the negative ion sources to be used on ITER, in terms of layout, dimensions and operating parameters. The SPIDER beam source will be housed inside a vacuum vessel which will be equipped with a beam dump and a graphite diagnostic calorimeter. The manufacturing design of the main parts of the SPIDER beam source has been completed and many of the tests on the prototypes have been successfully passed. The most complex parts, from the manufacturing point of view, of the ion source and the accelerator, developed by galvanic deposition of copper are being manufactured. The manufacturing phase will be completed within 2015, when the assembly of the device will start at the PRIMA site, in Padova (I). The paper describes the status of the procurement, the adaptations operated on the design of the beam

  12. Stochastic orbit loss of neutral beam ions from NSTX due to toroidal Alfvén eigenmode avalanches

    Energy Technology Data Exchange (ETDEWEB)

    Darrow, D. S. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Crocker, N. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics; Fredrickson, E. D. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Gorelenkov, N. N. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Gorelenkova, M. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Kubota, S. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics; Medley, S. S. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Podestà, M. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Shi, L. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); White, R. B. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    2012-12-17

    Short toroidal Alfvén eigenmode (TAE) avalanche bursts in the National Spherical Torus Experiment (NSTX) cause a drop in the neutron rate and could also cause a loss of neutral beam ions at or near the full injection energy over an extended range of pitch angles. The simultaneous loss of wide ranges of pitch angle suggests stochastic transport of the beam ions takes place. When beam ion orbits are followed with a guiding centre code that incorporates the plasma's magnetic equilibrium plus the measured modes, the predicted ranges of lost pitch angle are like those seen in the experiment, with distinct populations of trapped and passing orbits lost. These correspond to domains where the stochasticity extends in the orbit phase space from the region of beam ion deposition to the loss boundary and the trajectories along which modes may transport particles extend from the deposition volume to the loss boundary.

  13. Al and Ge simultaneous oxidation using neutral beam post-oxidation for formation of gate stack structures

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, Takeo, E-mail: t-ohno@wpi-aimr.tohoku.ac.jp [WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Japan Science and Technology Agency (JST), PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Nakayama, Daiki [Institute of Fluid Science (IFS), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Samukawa, Seiji, E-mail: samukawa@ifs.tohoku.ac.jp [WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Institute of Fluid Science (IFS), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan)

    2015-09-28

    To obtain a high-quality Germanium (Ge) metal–oxide–semiconductor structure, a Ge gate stacked structure was fabricated using neutral beam post-oxidation. After deposition of a 1-nm-thick Al metal film on a Ge substrate, simultaneous oxidation of Al and Ge was carried out at 300 °C, and a Ge oxide film with 29% GeO{sub 2} content was obtained by controlling the acceleration bias power of the neutral oxygen beam. In addition, the fabricated AlO{sub x}/GeO{sub x}/Ge structure achieved a low interface state density of less than 1 × 10{sup 11 }cm{sup −2 }eV{sup −1} near the midgap.

  14. Beam optics in a MeV-class multi-aperture multi-grid accelerator for the ITER neutral beam injector.

    Science.gov (United States)

    Kashiwagi, M; Taniguchi, M; Umeda, N; de Esch, H P L; Grisham, L R; Boilson, D; Hemsworth, R S; Tanaka, M; Tobari, H; Watanabe, K; Inoue, T

    2012-02-01

    In a multi-aperture multi-grid accelerator of the ITER neutral beam injector, the beamlets are deflected due to space charge repulsion between beamlets and beam groups, and also due to magnetic field. Moreover, the beamlet deflection is influenced by electric field distortion generated by grid support structure. Such complicated beamlet deflections and the compensations have been examined utilizing a three-dimensional beam analysis. The space charge repulsion and the influence by the grid support structure were studied in a 1∕4 model of the accelerator including 320 beamlets. Beamlet deflection due to the magnetic field was studied by a single beamlet model. As the results, compensation methods of the beamlet deflection were designed, so as to utilize a metal bar (so-called field shaping plate) of 1 mm thick beneath the electron suppression grid (ESG), and an aperture offset of 1 mm in the ESG.

  15. Investigation of beam deflection reduction and multi-beamlet focus at a large-area negative ion source for a neutral beam injector with 3-D beam trajectory simulation

    CERN Document Server

    Tanaka, M; Asano, E; Oka, Y; Osakabe, M; Tsumori, K; Kaneko, O; Yamashita, Y

    2000-01-01

    We investigated the reduction of ion beam deflection caused by electron deflection magnets, and focus of multi-beamlets at a large-area negative ion source of a neutral beam injector (NBI) in order to reduce beam loss during long-distance beam transport (>10 m) and beam injection into a nuclear fusion device. The electrostatic lens effect by displacement of the beam extraction aperture of a grounded grid (GG) was utilized for the beam deflection reduction and the multi-beamlet focus. We proposed an analysis process to adjust the aperture displacement which avoids beam collision with the GG by too much displacement. The analysis process includes a 3-D beam trajectory simulation used for analyzing the beam deflection angle and beam radius as well as theoretical calculations, which are used to calculate the aperture displacement based on the 3-D simulation results. Applicability of the analysis process was examined for a large-area high-current H sup - ion source of an NBI (0.25 mx1.25 m, 40 A, 180 keV). The ana...

  16. Effects of errors in velocity tilt on maximum longitudinal compression during neutralized drift compression of intense beam pulses: II. Analysis of experimental data of the Neutralized Drift Compression eXperiment-I (NDCX-I)

    Science.gov (United States)

    Massidda, Scott; Kaganovich, Igor D.; Startsev, Edward A.; Davidson, Ronald C.; Lidia, Steven M.; Seidl, Peter; Friedman, Alex

    2012-06-01

    Neutralized drift compression offers an effective means for particle beam focusing and current amplification with applications to heavy ion fusion. In the Neutralized Drift Compression eXperiment-I (NDCX-I), a non-relativistic ion beam pulse is passed through an inductive bunching module that produces a longitudinal velocity modulation. Due to the applied velocity tilt, the beam pulse compresses during neutralized drift. The ion beam pulse can be compressed by a factor of more than 100; however, errors in the velocity modulation affect the compression ratio in complex ways. We have performed a study of how the longitudinal compression of a typical NDCX-I ion beam pulse is affected by the initial errors in the acquired velocity modulation. Without any voltage errors, an ideal compression is limited only by the initial energy spread of the ion beam, ΔΕb. In the presence of large voltage errors, δU≫ΔEb, the maximum compression ratio is found to be inversely proportional to the geometric mean of the relative error in velocity modulation and the relative intrinsic energy spread of the beam ions. Although small parts of a beam pulse can achieve high local values of compression ratio, the acquired velocity errors cause these parts to compress at different times, limiting the overall compression of the ion beam pulse.

  17. Effects of errors in velocity tilt on maximum longitudinal compression during neutralized drift compression of intense beam pulses: II. Analysis of experimental data of the Neutralized Drift Compression eXperiment-I (NDCX-I)

    Energy Technology Data Exchange (ETDEWEB)

    Massidda, Scott [Plasma Physics Laboratory, Princeton University, Princeton, NJ 08543 (United States); Kaganovich, Igor D., E-mail: ikaganov@pppl.gov [Plasma Physics Laboratory, Princeton University, Princeton, NJ 08543 (United States); Startsev, Edward A.; Davidson, Ronald C. [Plasma Physics Laboratory, Princeton University, Princeton, NJ 08543 (United States); Lidia, Steven M.; Seidl, Peter [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Friedman, Alex [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States)

    2012-06-21

    Neutralized drift compression offers an effective means for particle beam focusing and current amplification with applications to heavy ion fusion. In the Neutralized Drift Compression eXperiment-I (NDCX-I), a non-relativistic ion beam pulse is passed through an inductive bunching module that produces a longitudinal velocity modulation. Due to the applied velocity tilt, the beam pulse compresses during neutralized drift. The ion beam pulse can be compressed by a factor of more than 100; however, errors in the velocity modulation affect the compression ratio in complex ways. We have performed a study of how the longitudinal compression of a typical NDCX-I ion beam pulse is affected by the initial errors in the acquired velocity modulation. Without any voltage errors, an ideal compression is limited only by the initial energy spread of the ion beam, {Delta}{Epsilon}{sub b}. In the presence of large voltage errors, {delta}U Double-Nested-Greater-Than {Delta}E{sub b}, the maximum compression ratio is found to be inversely proportional to the geometric mean of the relative error in velocity modulation and the relative intrinsic energy spread of the beam ions. Although small parts of a beam pulse can achieve high local values of compression ratio, the acquired velocity errors cause these parts to compress at different times, limiting the overall compression of the ion beam pulse.

  18. Gamma-ray scintillation counter hodoscope for the experiment S140

    CERN Multimedia

    1975-01-01

    The experiment S140 was set-up in the East Hall (beam p14) by the CERN-Munich-Cracow Collaboration to study the production by negative kaons of a neutral meson associated to a Lambda. Here, the liquid hydrogen target (inside the horizontal black tube) is withdrawn from the surrounding cylindrical gamma-ray-measuring scintillation counter hodoscope.

  19. Voltage holding study of 1 MeV accelerator for ITER neutral beam injector.

    Science.gov (United States)

    Taniguchi, M; Kashiwagi, M; Umeda, N; Dairaku, M; Takemoto, J; Tobari, H; Tsuchida, K; Yamanaka, H; Watanabe, K; Kojima, A; Hanada, M; Sakamoto, K; Inoue, T

    2012-02-01

    Voltage holding test on MeV accelerator indicated that sustainable voltage was a half of that of ideal quasi-Rogowski electrode. It was suggested that the emission of the clumps is enhanced by a local electric field concentration, which leads to discharge initiation at lower voltage. To reduce the electric field concentration in the MeV accelerator, gaps between the grid supports were expanded and curvature radii at the support corners were increased. After the modifications, the accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. However, the beam energy was still limited at a level of 900 keV with a beam current density of 150 A∕m(2) (346 mA) where the 3 × 5 apertures were used. Measurement of the beam profile revealed that deflection of the H(-) ions was large and a part of the H(-) ions was intercepted at the acceleration grid. This causes high heat load on the grids and the breakdowns during beam acceleration. To suppress the direct interception, new grid system was designed with proper aperture displacement based on a 3D beam trajectory analysis. As the result, the beam deflection was compensated and the voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A∕m(2) (427 mA), which is close to the requirement of ITER accelerator (1 MeV, 200 A∕m(2)).

  20. Neutral and color-selective beam splitting assemblies with polarization-independent intensities.

    Science.gov (United States)

    Ho, F C; Dobrowolski, J A

    1992-07-01

    Arrangements consisting of at least three beam splitting surfaces are described that give rise to at least four different beams, of which at least two have polarization-independent spectral intensities. They can act over a wide spectral region and can be designed to be either achromatic or color selective. The performance of an experimentally produced device is described.

  1. Progress toward fully noninductive discharge operation in DIII-D using off-axis neutral beam injection

    Energy Technology Data Exchange (ETDEWEB)

    Ferron, J. R.; Luce, T. C.; Politzer, P. A.; Hyatt, A. W.; La Haye, R. J.; Lanctot, M. J.; Petrie, T. W.; Petty, C. C. [General Atomics, PO Box 85608, San Diego, California 92186-5608 (United States); Holcomb, C. T. [Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, California 94550-9234 (United States); Park, J. M. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Turco, F.; Hanson, J. M. [Columbia University, 116th St and Broadway, New York, New York 10027 (United States); Heidbrink, W. W. [University of California, Irvine, University Dr., Irvine, California 92697 (United States); Doyle, E. J.; Zeng, L. [University of California, Los Angeles, PO Box 957099, Los Angeles, California 90095-7099 (United States); In, Y. [FAR-TECH, Inc., 10350 Science Center Dr., San Diego, California 92121-1136 (United States); Okabayashi, M. [Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543-0451 (United States)

    2013-09-15

    The initial experiments on off-axis neutral beam injection into high noninductive current fraction (f{sub NI}), high normalized pressure (β{sub N}) discharges in DIII-D [J. L. Luxon, Fusion Sci. Technol. 48, 828 (2005)] have demonstrated changes in the plasma profiles that increase the limits to plasma pressure from ideal low-n instabilities. The current profile is broadened and the minimum value of the safety factor (q{sub min}) can be maintained above 2 where the profile of the thermal component of the plasma pressure is found to be broader. The off-axis neutral beam injection results in a broadening of the fast-ion pressure profile. Confinement of the thermal component of the plasma is consistent with the IPB98(y,2) scaling, but global confinement with q{sub min}>2 is below the ITER-89P scaling, apparently as a result of enhanced transport of fast ions. A 0-D model is used to examine the parameter space for f{sub NI}=1 operation and project the requirements for high performance steady-state discharges. Fully noninductive solutions are found with 4<β{sub N}<5 and bootstrap current fraction near 0.5 for a weak shear safety factor profile. A 1-D model is used to show that a f{sub NI}=1 discharge at the top of this range of β{sub N} that is predicted stable to n=1, 2, and 3 ideal MHD instabilities is accessible through further broadening of the current and pressure profiles with off-axis neutral beam injection and electron cyclotron current drive.

  2. MHD Instabilities and Their Effects on Plasma Confinement in Large Helical Device Plasmas with Intense Neutral Beam Injection

    Institute of Scientific and Technical Information of China (English)

    K. Toi; K. Narihara; K. Tanaka; T. Tokuzawa; H. Yamada; Q. Yang; LHD experimental group; S. Ohdachi; S. Yamamoto; S. Sakakibara; K. Y. Watanabe; N. Nakajima; X. Ding; J. Li; S. Morita

    2004-01-01

    MHD stability of the Large Helical Device (LHD) plasmas produced with intense neutral beam injection is experimentally studied. When the steep pressure gradient near the edge is produced through L-H transition or linear density ramp experiment, interchange-like MHD modes whose rational surface is located very close to the last closed flux surface are strongly excited in a certain discharge condition and affect the plasma transport appreciably. In NBI-heated energetic ion loss, but also trigger the formation of internal and edge transport barriers.

  3. Work function measurements during plasma exposition at conditions relevant in negative ion sources for the ITER neutral beam injection.

    Science.gov (United States)

    Gutser, R; Wimmer, C; Fantz, U

    2011-02-01

    Cesium seeded sources for surface generated negative hydrogen ions are major components of neutral beam injection systems in future large-scale fusion experiments such as ITER. The stability and delivered current density depend highly on the work function during vacuum and plasma phases of the ion source. One of the most important quantities that affect the source performance is the work function. A modified photocurrent method was developed to measure the temporal behavior of the work function during and after cesium evaporation. The investigation of cesium exposed Mo and MoLa samples under ITER negative hydrogen ion based neutral beam injection relevant surface and plasma conditions showed the influence of impurities which result in a fast degradation when the plasma exposure or the cesium flux onto the sample is stopped. A minimum work function close to that of bulk cesium was obtained under the influence of the plasma exposition, while a significantly higher work function was observed under ITER-like vacuum conditions.

  4. The earthing system of the PRIMA Neutral Beam Test Facility based on the Mesh Common Bonding Network topology

    Energy Technology Data Exchange (ETDEWEB)

    Pomaro, Nicola, E-mail: nicola.pomaro@igi.cnr.it; Boldrin, Marco; Lazzaro, Gabriele

    2015-10-15

    Highlights: • We designed a high performance earthing system for the ITER Neutral Beam Test Facility. • The system is based on the Mesh Common Bonded Network topology. • Careful bonding of all metallic structures allowed to obtain a well meshed system. • Special care was dedicated to improve EMC performance of critical areas like control rooms. • The facility experimental results will be representative also of the ITER situation. - Abstract: PRIMA is a large experimental facility under realization in Padova, aimed at developing and testing the Neutral Beam Injectors for ITER. The operation of these devices involves high RF power and voltage up to 1 MV. Frequent and high voltage electrical breakdowns inside the beam sources occur regularly. The presence of a distributed carefully optimized earthing system is of paramount importance to achieve a satisfying disturbances immunity for equipment and diagnostics. The paper describes the design and the realization of the earthing system of the PRIMA facility, which is based on the MESH-Common Bonding Network (MESH-CBN) topology, as recommended by IEC and IEEE standards for installations with high levels of Electromagnetic Interferences (EMI). The principles of the MESH-CBN approach were adapted to the PRIMA layout, which is composed by several buildings, that are independent for seismic and architectural reasons, but are linked by many electrical conduits and hydraulic pipelines. The availability of huge foundations, with a large number of poles and pillars, was taken into account; building parts dedicated to host control rooms and sensitive equipment were treated with particular care. Moreover, the lightning protection system was integrated and harmonized with the earthing system.

  5. Workshop on Physics with Neutral Kaon Beam at JLab (KL2016) Mini-Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Strakovsky, Igor I. [George Washington Univ., Washington, DC (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Amaryan, Moskov [Old Dominion Univ., Norfolk, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Chudakov, Eugene A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Meyer, Curtis A. [Carnegie Mellon Univ., Pittsburgh, PA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Pennington, Michael R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Ritman, James L. [Forschungszentrum Juelich Institut fuer Kernphysik

    2016-05-01

    The KL2016 Workshop is following the Letter of Intent LoI12-15-001 "Physics Opportunities with Secondary KL beam at JLab" submitted to PAC43 with the main focus on the physics of excited hyperons produced by the Kaon beam on unpolarized and polarized targets with GlueX setup in Hall D. Such studies will broaden a physics program of hadron spectroscopy extending it to the strange sector. The Workshop was organized to get a feedback from the community to strengthen physics motivation of the LoI and prepare a full proposal.

  6. Progress of the Hard-wired Instrumentation and Control Works for the Neutral Beam Test Stand at KAERI

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Ki Sok

    2005-12-15

    Progress of the hard-wired instrumentation and control works for the neutral beam test stand(NB-TS) has been existed for the past one year period. Details of the installed arc detector circuit are explained. LN{sub 2} level and temperature control during the cryosorption pumping operation are explained with an emphasis on its control circuit. With an expectation of more accurate and sensitive measurement of temperatures than the thermocouple utilization during the calorimeter operation, PT-100 resistance temperature detector(RTD) utilization is initiated and the results are described. During the ion beam experiment, physical measurements are made with some delayed time than the beam extraction, and thus a delayed trigger pulse generator was fabricated and installed to the system. Underlying principles of the electronic circuits for the interlock implementation and optical signal transmission are introduced. These are basically the application of operational amplifier circuits. A cautious aspect of the SMPS(switch mode power supply) utilization is also give.

  7. FLUKA simulations of the response of tissue-equivalent proportional counters to ion beams for applications in hadron therapy and space.

    Science.gov (United States)

    Böhlen, T T; Dosanjh, M; Ferrari, A; Gudowska, I; Mairani, A

    2011-10-21

    For both cancer therapy with protons and ions (hadron therapy) and space radiation environments, the spatial energy deposition patterns of the radiation fields are of importance for quantifying the resulting radiation damage in biological structures. Tissue-equivalent proportional counters (TEPC) are the principal instruments for measuring imparted energy on a microscopic scale and for characterizing energy deposition patterns of radiation. Moreover, the distribution of imparted energy can serve as a complementary quantity to particle fluences of the primary beam and secondary fragments for characterizing a radiation field on a physical basis for radiobiological models. In this work, the Monte Carlo particle transport code FLUKA is used for simulating energy depositions in TEPC by ion beams. The capability of FLUKA in predicting imparted energy and derived quantities, such as lineal energy, for microscopic volumes is evaluated by comparing it with a large set of TEPC measurements for different ion beams with atomic numbers ranging from 1 to 26 and energies from 80 up to 1000 MeV/n. The influence of different physics configurations in the simulation is also discussed. It is demonstrated that FLUKA can simulate energy deposition patterns of ions in TEPC cavities accurately and that it provides an adequate description of the main features of the spectra.

  8. Review of the neutral-beam current requirements for the Mirror Fusion Test Facility (MFTF)

    Energy Technology Data Exchange (ETDEWEB)

    Porter, G.D.; Coensgen, F.H.; Devoto, R.S.; Molvik, A.W.; Osher, J.F.; Shearer, J.W.; Thomassen, K.I.

    1978-08-04

    The techniques used to evaluate the beam-current requirements for MFTF are similar to those in previous studies but incorporate some improvements. In particular, we have enlarged the radial code BUILDUP to allow for a smaller radial grid and to improve the numerical accuracy; we have also improved the model of the atomic physics processes and the particle-equilibrium calculations. Also, a model of plasma containment that conserves energy as well as particles but does not include any effect of the expected drift-cyclotron loss-cone (DCLC) turbulence has been incorporated into the previous studies. We show that the DCLC turbulence increases the average ion energy and decreases the particle confinement time. Because these effects cancel to first order, the beam-current requirements are independent of the turbulence. We find that 24 of the present LBL source modules would sustain a plasma with an average beta of 0.46. This figure is within 10% of the MFTF goal and is within our calculational accuracies. We further show that the beam-current requirements for the large-diameter plasma are consistent with those of experiments to study the buildup of a field-reversed plasma.

  9. Simultaneous Counter-Ion Co-Deposition a Technique Enabling Matrix Isolation Spectroscopy Studies Using Low-Energy Beams of Mass-Selected Ions

    Science.gov (United States)

    Ludwig, Ryan M.; Moore, David T.

    2014-06-01

    Matrix isolation spectroscopy was first developed in Pimentel's group during the 1950's to facilitate spectroscopic studies of transient species. Cryogenic matrices of condensed rare gases provide an inert chemical environment with facile energy dissipation and are transparent at all wavelengths longer than vacuum UV, making them ideal for studying labile and reactive species such as radicals, weakly bound complexes, and ions. Since frozen rare gases are poor electrolytes, studies of ions require near-equal populations of anions and cations in order to stabilize the number densities required for spectroscopic experiments. Many techniques for generation of ions for using in matrix isolation studies satisfy this criterion intrinsically, however when ion beams generated in external sources are deposited, the counter-ions typically arise via secondary processes that are at best loosely controlled. It has long been recognized that it would be desirable to stabilize deposition of mass-selected ions generated in an external source using simultaneous co-deposition of a beam of counter-ions, however previous attempts to achieve this have been reported as unsuccessful. The Moore group at Lehigh has demonstrated successful experiments of this type, using mass-selected anions generated from a metal cluster source, co-deposited with a balanced current of cations generated in a separate electron ionization source. This talk will focus on the details of the technique, and present some results from proof-of-concept studies on anionic copper carbonyl complexes formed in argon matrices following co-deposition of Cu- with Ar+ or Kr+. Funding support from NSF CAREER Award CHE-0955637 is gratefully acknowledged. Whittle et al., J. Chem. Phys. 22, p.1943 (1954); Becker et al., J. Chem. Phys. 25, p.224 (1956). Godbout et al., J. Chem. Phys. 96, p.2892 (1996). Sabo et al., Appl. Spectrosc. 45, p. 535 (1991).

  10. Electrostatic deflection of a molecular beam of massive neutral particles: Fully field-oriented polar molecules within superfluid nanodroplets

    CERN Document Server

    Merthe, Daniel J

    2016-01-01

    Electric deflection measurements on liquid helium nanodroplets doped with individual polar molecules demonstrate that the cold superfluid matrix enables full orientation of the molecular dipole along the external field. This translates into a deflection force which is increased enormously by comparison with typical deflection experiments, and it becomes possible to measurably deflect neutral doped droplets with masses of tens to hundreds of thousands of Daltons. This approach permits preparation and study of continuous fluxes of fully oriented polar molecules and is broadly and generally applicable, including to complex and biological molecules. It is shown that the dipole moments of internally cryogenically cold molecules can be directly determined from a deflection measurement on the doped nanodroplet beam.

  11. Design status and procurement activities of the High Voltage Deck 1 and Bushing for the ITER Neutral Beam Injector

    Energy Technology Data Exchange (ETDEWEB)

    Boldrin, Marco, E-mail: marco.boldrin@igi.cnr.it [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); De Lorenzi, Antonio [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Decamps, Hans [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Grando, Luca [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Simon, Muriel [Fusion For Energy, c/ Josep Pla 2, 08019 Barcelona (Spain); Toigo, Vanni [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy)

    2013-10-15

    Highlights: ► ITER Neutral Beam Injector includes several non-standard components. ► The design status of the −1 MV{sub dc} HVD1 and Bushing is described. ► The paper reports also on the integrated layout of the two components. ► Preliminary electrostatic and thermal analyses are presented. ► Procurement activities are outlined. -- Abstract: The ITER Neutral Beam Injector (NBI) power supply system includes several non-standard components, whose ratings go beyond the present industrial practice. Two of these items, to be procured by Fusion for Energy, are: 1.A −1 MV{sub dc} air-insulated Faraday cage, called High Voltage Deck 1 (HVD1), hosting the Ion Source and Extractor Power Supplies (ISEPS) and the associated diagnostics. 2.A −1 MV{sub dc} feedthrough, called HVD1-TL Bushing, aimed at connecting the HVD1 to the gas (SF{sub 6}) insulated Transmission Line (TL), containing inside its High Voltage (HV) conductor all ISEPS power and control cables coming from the HVD1 to be connected to the NBI Ion Source services. The paper deals with the status of the design of the HVD1 and HVD1-TL Bushing, focusing on insulation, mechanical and thermal issues as well as on their integration with the other components of the power supply system. In particular, the insulation issue of the integrated system has been addressed by means of an electrostatic Finite Element (FE) analysis whilst a FE thermal simulation has been carried out to assess the impact of the dissipation of the proposed design of the inner conductors (ISEPS conductors) not actively cooled. Finally, the paper describes the status of procurement strategy and execution.

  12. Neutral Beam Source and Target Plasma for Development of a Local Electric Field Fluctuation Diagnostic

    Science.gov (United States)

    Bakken, M. R.; Burke, M. G.; Fonck, R. J.; Lewicki, B. T.; Rhodes, A. T.; Winz, G. R.

    2016-10-01

    A new diagnostic measuring local E-> (r , t) fluctuations is being developed for plasma turbulence studies in tokamaks. This is accomplished by measuring fluctuations in the separation of the π components in the Hα motional Stark spectrum. Fluctuations in this separation are expected to be Ẽ / ẼEMSE 10-3EMSE 10-3 . In addition to a high throughput, high speed spectrometer, the project requires a low divergence (Ω 0 .5°) , 80 keV, 2.5 A H0 beam and a target plasma test stand. The beam employs a washer-stack arc ion source to achieve a high species fraction at full energy. Laboratory tests of the ion source demonstrate repeatable plasmas with Te 10 eV and ne 1.6 ×1017 m-3, sufficient for the beam ion optics requirements. Te and ne scalings of the ion source plasma are presented with respect to operational parameters. A novel three-phase resonant converter power supply will provide 6 mA/cm2 of 80 keV H0 at the focal plane for pulse lengths up to 15 ms, with low ripple δV / 80 keV 0.05 % at 280 kHz. Diagnostic development and validation tests will be performed on a magnetized plasma test stand with 0.5 T field. The test chamber will utilize a washer-stack arc source to produce a target plasma comparable to edge tokamak plasmas. A bias-plate with programmable power supply will be used to impose Ẽ within the target plasma. Work supported by US DOE Grant DE-FG02-89ER53296.

  13. Design of a tokamak fusion reactor first wall armor against neutral beam impingement

    Energy Technology Data Exchange (ETDEWEB)

    Myers, R.A.

    1977-12-01

    The maximum temperatures and thermal stresses are calculated for various first wall design proposals, using both analytical solutions and the TRUMP and SAP IV Computer Codes. Beam parameters, such as pulse time, cycle time, and beam power, are varied. It is found that uncooled plates should be adequate for near-term devices, while cooled protection will be necessary for fusion power reactors. Graphite and tungsten are selected for analysis because of their desirable characteristics. Graphite allows for higher heat fluxes compared to tungsten for similar pulse times. Anticipated erosion (due to surface effects) and plasma impurity fraction are estimated. Neutron irradiation damage is also discussed. Neutron irradiation damage (rather than erosion, fatigue, or creep) is estimated to be the lifetime-limiting factor on the lifetime of the component in fusion power reactors. It is found that the use of tungsten in fusion power reactors, when directly exposed to the plasma, will cause serious plasma impurity problems; graphite should not present such an impurity problem.

  14. Low pressure and high power rf sources for negative hydrogen ions for fusion applications (ITER neutral beam injection).

    Science.gov (United States)

    Fantz, U; Franzen, P; Kraus, W; Falter, H D; Berger, M; Christ-Koch, S; Fröschle, M; Gutser, R; Heinemann, B; Martens, C; McNeely, P; Riedl, R; Speth, E; Wünderlich, D

    2008-02-01

    The international fusion experiment ITER requires for the plasma heating and current drive a neutral beam injection system based on negative hydrogen ion sources at 0.3 Pa. The ion source must deliver a current of 40 A D(-) for up to 1 h with an accelerated current density of 200 Am/(2) and a ratio of coextracted electrons to ions below 1. The extraction area is 0.2 m(2) from an aperture array with an envelope of 1.5 x 0.6 m(2). A high power rf-driven negative ion source has been successfully developed at the Max-Planck Institute for Plasma Physics (IPP) at three test facilities in parallel. Current densities of 330 and 230 Am/(2) have been achieved for hydrogen and deuterium, respectively, at a pressure of 0.3 Pa and an electron/ion ratio below 1 for a small extraction area (0.007 m(2)) and short pulses (ITER source but without extraction system, is intended to demonstrate the size scaling and plasma homogeneity of rf ion sources. The source operates routinely now. First results on plasma homogeneity obtained from optical emission spectroscopy and Langmuir probes are very promising. Based on the success of the IPP development program, the high power rf-driven negative ion source has been chosen recently for the ITER beam systems in the ITER design review process.

  15. Improvement of neutral beam injection heating efficiency with magnetic field well structures in a tokamak with a low magnetic field

    Science.gov (United States)

    Kim, S. K.; Na, D. H.; Lee, J. W.; Yoo, M. G.; Kim, H.-S.; Hwang, Y. S.; Hahm, T. S.; Na, Yong-Su

    2016-10-01

    Magnetic well structures are introduced as an effective means to reduce the prompt loss of fast ions, the so-called first orbit loss from neutral beam injection (NBI), which is beneficial to tokamaks with a low magnetic field strength such as small spherical torus devices. It is found by single-particle analysis that this additional field structure can modify the gradient of the magnetic field to reduce the shift of the guiding center trajectory of the fast ion. This result is verified by a numerical calculation of following the fast ion’s trajectory. We apply this concept to the Versatile Experiment Spherical Torus [1], where NBI is under design for the purpose of achieving high-performance plasma, to evaluate the effect of the magnetic well structure on NBI efficiency. A 1D NBI analysis code and the NUBEAM code are employed for detailed NBI calculations. The simulation results show that the orbit loss can be reduced by 70%-80%, thereby improving the beam efficiency twofold compared with the reference case without the well structure. The well-shaped magnetic field structure in the low-field side can significantly decrease orbit loss by broadening the non-orbit loss region and widening the range of the velocity direction, thus improving the heating efficiency. It is found that this magnetic well can also improve orbit loss during the slowing down process.

  16. Improved laser damage threshold performance of calcium fluoride optical surfaces via Accelerated Neutral Atom Beam (ANAB) processing

    Science.gov (United States)

    Kirkpatrick, S.; Walsh, M.; Svrluga, R.; Thomas, M.

    2015-11-01

    Optics are not keeping up with the pace of laser advancements. The laser industry is rapidly increasing its power capabilities and reducing wavelengths which have exposed the optics as a weak link in lifetime failures for these advanced systems. Nanometer sized surface defects (scratches, pits, bumps and residual particles) on the surface of optics are a significant limiting factor to high end performance. Angstrom level smoothing of materials such as calcium fluoride, spinel, magnesium fluoride, zinc sulfide, LBO and others presents a unique challenge for traditional polishing techniques. Exogenesis Corporation, using its new and proprietary Accelerated Neutral Atom Beam (ANAB) technology, is able to remove nano-scale surface damage and particle contamination leaving many material surfaces with roughness typically around one Angstrom. This surface defect mitigation via ANAB processing can be shown to increase performance properties of high intensity optical materials. This paper describes the ANAB technology and summarizes smoothing results for calcium fluoride laser windows. It further correlates laser damage threshold improvements with the smoothing produced by ANAB surface treatment. All ANAB processing was performed at Exogenesis Corporation using an nAccel100TM Accelerated Particle Beam processing tool. All surface measurement data for the paper was produced via AFM analysis on a Park Model XE70 AFM, and all laser damage testing was performed at Spica Technologies, Inc. Exogenesis Corporation's ANAB processing technology is a new and unique surface modification technique that has demonstrated to be highly effective at correcting nano-scale surface defects. ANAB is a non-contact vacuum process comprised of an intense beam of accelerated, electrically neutral gas atoms with average energies of a few tens of electron volts. The ANAB process does not apply mechanical forces associated with traditional polishing techniques. ANAB efficiently removes surface

  17. Ion temperature anisotropy in high power helium neutral beam fuelling experiments in JET

    Energy Technology Data Exchange (ETDEWEB)

    Maas, A.C.; Core, W.G.F.; Gerstel, U.C.; Von Hellermann, M.G.; Koenig, R.W.T.; Marcus, F.B. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

    1994-07-01

    During helium beam fuelling experiments in JET, distinctive anisotropic features have been observed in the velocity distribution function describing both fast and thermal alpha particle populations. During the initial fuelling phase the central helium ion temperature observed perpendicular to the magnetic field is higher than the central electron temperature, while the central helium ion temperature observed parallel to the magnetic field is lower than or equal to the central electron temperature. In order to verify temperature measurements of both perpendicular and parallel lines of sight, other independent methods of deducing the ion temperature are investigated: deuterium ion temperature, deuterium density, comparison with neutron rates and profiles (influence of a possible metastable population of helium). 6 refs., 7 figs.

  18. Development of heating device / development of the high current ion source for neutral beam injection

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Heon Ju; Lee, Dong Gyu; Lee, Kyong Jin; Ko Tae Kyong [Cheju National Univ., Cheju (Korea)

    1998-08-01

    The design and fabrication of a high current ion source for NBI was carried out. The scale of an ion source was reduced for mock-up test. To develop the high current ion source with the high operational stability and the long lifetime, the parameters including an arc current, gas pressure and extraction voltage should be optimized. If fabricated ion source would be tested, its parameters could be optimized experimentally. Through the optimization of the ion source parameter, the core technology for NBI is established and the experiment of current drive in the fusion device can be performed. This technology also can be applied to the ion beam technology in the field of new material synthesis and semiconductor industry. 24 refs., 22 figs., 13 tabs. (Author)

  19. Perturbative studies of toroidal momentum transport using neutral beam injection modulation in the Joint European Torus: Experimental results, analysis methodology, and first principles modeling

    DEFF Research Database (Denmark)

    Mantica, P.; Tala, T.; Ferreira, J.S.

    2010-01-01

    Perturbative experiments have been carried out in the Joint European Torus [Fusion Sci. Technol. 53(4) (2008)] in order to identify the diffusive and convective components of toroidal momentum transport. The torque source was modulated either by modulating tangential neutral beam power or by modu...

  20. Measurement of high-Q(2) neutral current deep inelastic e(-) p scattering cross sections with a longitudinally polarised electron beam at HERA

    NARCIS (Netherlands)

    Chekanov, S.; Derrick, M.; Magill, S.; Musgrave, B.; Nicholass, D.; Repond, J.; Yoshida, R.; Mattingly, M. C. K.; Antonioli, P.; Bari, G.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cindolo, F.; Corradi, M.; Iacobucci, G.; Margotti, A.; Nania, R.; Polini, A.; Antonelli, S.; Basile, M.; Bindi, M.; Cifarelli, L.; Contin, A.; De Pasquale, S.; Sartorelli, G.; Zichichi, A.; Bartsch, D.; Brock, I.; Hartmann, H.; Hilger, E.; Jakob, H. P.; Juengst, M.; Nuncio-Quiroz, A. E.; Samson, U.; Schoenberg, V.; Shehzadi, R.; Wlasenko, M.; Brook, N. H.; Heath, G. P.; Kaur, M.; Kaur, P.; Singh, I.; Capua, M.; Fazio, S.; Mastroberardino, A.; Schioppa, M.; Susinno, G.; Tassi, E.; Kim, J. Y.; Ibrahim, Z. A.; Mohamad Idris, F.; Kamaluddin, B.; Wan Abdullah, W. A. T.; Ning, Y.; Ren, Z.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Galas, A.; Olkiewicz, K.; Pawlik, B.; Stopa, P.; Zawiejski, L.; Adamczyk, L.; Bold, T.; Grabowska-Bold, I.; Kisielewska, D.; Lukasik, J.; Przybycien, M.; Suszycki, L.; Kotanski, A.; Slominski, W.; Behnke, O.; Behrens, U.; Blohm, C.; Bonato, A.; Borras, K.; Ciesielski, R.; Coppola, N.; Fourletova, J.; Geiser, A.; Goettlicher, P.; Grebenyuk, J.; Gregor, I.; Haas, T.; Hain, W.; Huettmann, A.; Januschek, F.; Kahle, B.; Katkov, I. I.; Klein, U.; Koetz, U.; Kowalski, H.; Lisovyi, M.; Lobodzinska, E.; Loehr, B.; Mankel, R.; Melzer-Pellmann, I. -A.; Miglioranzi, S.; Montanari, A.; Namsoo, T.; Notz, D.; Parenti, A.; Rinaldi, L.; Roloff, P.; Rubinsky, I.; Schneekloth, U.; Spiridonov, A.; Szuba, D.; Szuba, J.; Theedt, T.; Ukleja, J.; Wolf, G.; Wrona, K.; Molina, A. G. Yagues; Youngman, C.; Zeuner, W.; Drugakov, V.; Lohmann, W.; Schlenstedt, S.; Barbagli, G.; Gallo, E.; Pelfer, P. G.; Bamberger, A.; Dobur, D.; Karstens, F.; Vlasov, N. N.; Bussey, P. J.; Doyle, A. T.; Dunne, W.; Forrest, M.; Rosin, M.; Saxon, D. H.; Skillicorn, I. O.; Gialas, I.; Papageorgiu, K.; Holm, U.; Klanner, R.; Lohrmann, E.; Perrey, H.; Schleper, P.; Schoerner-Sadenius, T.; Sztuk, J.; Stadie, H.; Turcato, M.; Foudas, C.; Fry, C.; Long, K. R.; Tapper, A. D.; Matsumoto, T.; Nagano, K.; Tokushuku, K.; Yamada, S.; Yamazaki, Y.; Barakbaev, A. N.; Boos, E. G.; Pokrovskiy, N. S.; Zhautykov, B. O.; Aushev, V.; Bachynska, O.; Borodin, M.; Kadenko, I.; Kozulia, A.; Libov, V.; Lontkovskyi, D.; Makarenko, I.; Sorokin, Iu.; Verbytskyi, A.; Volynets, O.; Son, D.; de Favereau, J.; Piotrzkowski, K.; Barreiro, F.; Glasman, C.; Jimenez, M.; Labarga, L.; del Peso, J.; Ron, E.; Soares, M.; Terron, J.; Uribe-Estrada, C.; Zambrana, M.; Corriveau, F.; Schwartz, J.; Walsh, R.; Tsurugai, T.; Antonov, A.; Dolgoshein, B. A.; Gladkov, D.; Sosnovtsev, V.; Stifutkin, A.; Suchkov, S.; Dementiev, R. K.; Ermolov, P. F.; Gladilin, L. K.; Golubkov, Yu. A.; Khein, L. A.; Korzhavina, I. A.; Kuzmin, V. A.; Levchenko, B. B.; Lukina, O. Yu.; Proskuryakov, A. S.; Shcheglova, L. M.; Zotkin, D. S.; Abt, I.; Caldwell, A.; Kollar, D.; Reisert, B.; Schmidke, W. B.; Grigorescu, G.; Keramidas, A.; Kooijman, P.; Pellegrino, A.; Tiecke, H.; Vazquez, M.; Bruemmer, N.; Bylsma, B.; Durkin, L. S.; Lee, A.; Ling, T. Y.; Allfrey, P. D.; Bell, M. A.; Cooper-Sarkar, A. M.; Devenish, R. C. E.; Ferrando, J.; Foster, B.; Gwenlan, C.; Horton, K.; Oliver, K.; Robertson, A.; Walczak, R.; Bertolin, A.; Dal Corso, F.; Dusini, S.; Longhin, A.; Stanco, L.; Bellan, P.; Brugnera, R.; Carlin, R.; Garfagnini, A.; Limentani, S.; Oh, B. Y.; Raval, A.; Whitmore, J. J.; Iga, Y.; D'Agostini, G.; Marini, G.; Nigro, A.; Cole, J. E.; Hart, J. C.; Abramowicz, H.; Ingbir, R.; Kananov, S.; Stern, A.; Kuze, M.; Maeda, J.; Hori, R.; Kagawa, S.; Okazaki, N.; Tawara, T.; Hamatsu, R.; Kaji, H.; Kitamura, S.; Ota, O.; Ri, Y. D.; Costa, M.; Ferrero, M. I.; Monaco, V.; Sacchi, R.; Sola, V.; Solano, A.; Arneodo, M.; Ruspa, M.; Fourletov, S.; Stewart, T. P.; Boutle, S. K.; Butterworth, J. M.; Jones, T. W.; Loizides, J. H.; Wing, M.; Brzozowska, B.; Ciborowski, J.; Grzelak, G.; Kulinski, P.; Luzniak, P.; Malka, J.; Nowak, R. J.; Pawlak, J. M.; Perlanski, W.; Tymieniecka, T.; Zarnecki, A. F.; Adamus, M.; Plucinski, P.; Ukleja, A.; Eisenberg, Y.; Hochman, D.; Karshon, U.; Brownson, E.; Reeder, D. D.; Savin, A. A.; Smith, W. H.; Wolfe, H.; Bhadra, S.; Catterall, C. D.; Hartner, G.; Menary, S.; Noor, U.; Standage, J.; Whyte, J.

    2009-01-01

    Measurements of the neutral current cross sections for deep inelastic scattering in e(-) p collisions at HERA with a longitudinally polarised electron beam are presented. The single-differential cross-sections d sigma/dQ(2), d sigma/dx and d sigma/dy and the double-differential cross sections in Q(2

  1. Measurement of high-Q(2) neutral current deep inelastic e(+) p scattering cross sections with a longitudinally polarized positron beam at HERA

    NARCIS (Netherlands)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bold, T.; Bondarenko, K.; Boos, E. G.; Borras, K.; Boscherini, D.; Brock, I.; Brownson, E.; Brugnera, R.; Bruemmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Dal Corso, F.; Del Peso, J.; Dementiev, R. K.; De Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Dolinska, G.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Foster, B.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gizhko, A.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu. A.; Goettlicher, P.; Grabowska-Bold, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Huettmann, A.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jakob, H. -P.; Januschek, F.; Jones, T. W.; Juengst, M.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Kondrashova, N.; Kononenko, O.; Kooijman, P.; Korol, Ie.; Korzhavina, I. A.; Kotanski, A.; Koetz, U.; Kowalski, H.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B. B.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Loehr, B.; Lohrmann, E.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Mastroberardino, A.; Mattingly, M. C. K.; Melzer-Pellmann, I. -A.; Mergelmeyer, S.; Miglioranzi, S.; Idris, F. Mohamad; Monaco, V.; Montanari, A.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nigro, A.; Ning, Y.; Nobe, T.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Olkiewicz, K.; Onishchuk, Yu.; Papageorgiu, K.; Parenti, A.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. G.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N. S.; Polini, A.; Proskuryakov, A. S.; Przybycien, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schoenberg, V.; Schoerner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terron, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomaszewska, J.; Trusov, V.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Vazquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Walczak, R.; Abdullah, W. A. T. Wan; Whitmore, J. J.; Wichmann, K.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yaguees-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zabiegalov, O.; Zarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zichichi, A.; Zolkapli, Z.; Zotkin, D. S.

    2013-01-01

    Measurements of neutral current cross sections for deep inelastic scattering in e(+)p collisions at HERA with a longitudinally polarized positron beam are presented. The single-differential cross-sections d sigma=dQ(2), d sigma=dx and d sigma=dy and the reduced cross section (sigma) over tilde are m

  2. PIC code modeling of spacecraft charging potential during electron beam injection into a background of neutral gas and plasma, part 1

    Science.gov (United States)

    Koga, J. K.; Lin, C. S.; Winglee, R. M.

    1989-01-01

    Injections of nonrelativistic electron beams from an isolated equipotential conductor into a uniform background of plasma and neutral gas were simulated using a 2-D electrostatic particle code. The ionization effects on spacecraft charging are examined by including interactions of electrons with neutral gas. The simulations show that the conductor charging potential decreases with increasing neutral background density due to the production of secondary electrons near the conductor surface. In the spacecraft wake, the background electrons accelerated towards the charged spacecraft produce an enhancement of secondary electrons and ions. Simulations run for longer times indicate that the spacecraft potential is further reduced and short wavelength beam-plasma oscillations appear. The results are applied to explain the spacecraft charging potential measured during the SEPAC experiments from Spacelab 1.

  3. Development of a low-energy and high-current pulsed neutral beam injector with a washer-gun plasma source for high-beta plasma experiments.

    Science.gov (United States)

    Ii, Toru; Gi, Keii; Umezawa, Toshiyuki; Asai, Tomohiko; Inomoto, Michiaki; Ono, Yasushi

    2012-08-01

    We have developed a novel and economical neutral-beam injection system by employing a washer-gun plasma source. It provides a low-cost and maintenance-free ion beam, thus eliminating the need for the filaments and water-cooling systems employed conventionally. In our primary experiments, the washer gun produced a source plasma with an electron temperature of approximately 5 eV and an electron density of 5 × 10(17) m(-3), i.e., conditions suitable for ion-beam extraction. The dependence of the extracted beam current on the acceleration voltage is consistent with space-charge current limitation, because the observed current density is almost proportional to the 3/2 power of the acceleration voltage below approximately 8 kV. By optimizing plasma formation, we successfully achieved beam extraction of up to 40 A at 15 kV and a pulse length in excess of 0.25 ms. Its low-voltage and high-current pulsed-beam properties enable us to apply this high-power neutral beam injection into a high-beta compact torus plasma characterized by a low magnetic field.

  4. An efficient anticoincidence counter

    CERN Multimedia

    1977-01-01

    This scintillation counter (about 25 cm diameter) was prepared at CERN for an experiment at the Saclay 600 MeV electron linac studying molecular processes originated in liquid hydrogen by muons. The counter is meant to surround the target and detect charged particles emerging from the hydrogen. The experiment was a CERN-Saclay collaboration which used the linac so as to take advantage of the time structure of the electron beam(see CERN Courier Sep 1977 and J. Bardin et al. Phys. Lett. B104 (1981) 320)

  5. Design of the 'half-size' ITER neutral beam source for the test facility ELISE

    Energy Technology Data Exchange (ETDEWEB)

    Heinemann, B. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Postfach 1533, D-85740 Garching (Germany)], E-mail: bernd.heinemann@ipp.mpg.de; Falter, H.; Fantz, U.; Franzen, P.; Froeschle, M.; Gutser, R.; Kraus, W.; Nocentini, R.; Riedl, R.; Speth, E.; Staebler, A.; Wuenderlich, D. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Postfach 1533, D-85740 Garching (Germany); Agostinetti, P. [Consorzio RFX, EURATOM Association, Corso Stati Uniti 4, I-35127 Padova (Italy); Jiang, T. [Southwestern Institute of Physics, ChengDu (China)

    2009-06-15

    In 2007 the radio frequency driven negative hydrogen ion source developed at IPP in Garching was chosen by the ITER board as the new reference source for the ITER neutral beam system. In order to support the design and the commissioning and operating phases of the ITER test facilities ISTF and NBTF in Padua, IPP is presently constructing a new test facility ELISE (Extraction from a Large Ion Source Experiment). ELISE will be operated with the so-called 'half-size ITER source' which is an intermediate step between the present small IPP RF sources (1/8 ITER size) and the full size ITER source. The source will have approximately the width but only half the height of the ITER source. The modular concept with 4 drivers will allow an easy extrapolation to the full ITER size with 8 drivers. Pulsed beam extraction and acceleration up to 60 kV (corresponding to pre-acceleration voltage of SINGAP) is foreseen. The aim of the design of the ELISE source and extraction system was to be as close as possible to the ITER design; it has however some modifications allowing a better diagnostic access as well as more flexibility for exploring open questions. Therefore one major difference compared to the source of ITER, NBTF or ISTF is the possible operation in air. Specific requirements for RF sources as found on IPP test facilities BATMAN and MANITU are implemented [A. Staebler, et al., Development of a RF-driven ion source for the ITER NBI system, SOFT Conference 2008, Fusion Engineering and Design, 84 (2009) 265-268].

  6. The Influence of Neutral Beam Injection on the Heating and Current Drive with Electron Cyclotron Wave on EAST

    Science.gov (United States)

    Chang, Pengxiang; Wu, Bin; Wang, Jinfang; Li, Yingying; Wang, Xiaoguang; Xu, Handong; Wang, Xiaojie; Liu, Yong; Zhao, Hailin; Hao, Baolong; Yang, Zhen; Zheng, Ting; Hu, Chundong

    2016-11-01

    Both neutral beam injection (NBI) and electron cyclotron resonance heating (ECRH) have been applied on the Experimental Advanced Superconducting Tokamak (EAST) in the 2015 campaign. In order to achieve more effective heating and current drive, the effects of NBI on the heating and current drive with electron cyclotron wave (ECW) are analyzed utilizing the code TORAY and experimental data in the shot #54411 and #54417. According to the experimental and simulated results, for the heating with ECW, NBI can improve the heating efficiency and move the power deposition place towards the inside of the plasma. On the other hand, for the electron cyclotron current drive (ECCD), NBI can also improve the efficiency of ECCD and move the place of ECCD inward. These results will be valuable for the center heating, the achievement of fully non-inductive current drive operation and the suppression of magnetohydrodynamic (MHD) instabilities with ECW on EAST or ITER with many auxiliary heating methods. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB101001 and 2014DFG61950) and National Natural Science Foundation of China (Nos. 11405212 and 11175211)

  7. FABRICATION AND REPAIR OF ION SOURCE COMPONENTS IN THE 80 keV NEUTRAL BEAM LINES FOR DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    GRUNLOH,H.J; BUSATH,J.L; CALLIS,R.W; CHIU,H.K; DiMARTINO,M; HONG,R; KLASEN,R; MOELLER,C.P; ROBINSON,J.I; STRECKERT,H.H; TAO,R; TRESTER,P.W

    2003-10-01

    OAK-B135 After 8 years of operation, leaks began to develop in critical components of the ion sources of the 80 keV neutral beam lines in DIII-D. Operational adjustments were made that seemed to remedy the problems, but five years later leaks began occurring again, this time with greater frequency. Failures occurred in the stainless steel bellows and molybdenum rails of the grid rail modules as well as in the Langmuir probes. Failure analyses identified several root causes of the leaks and operational adjustments were again made to mitigate the problems, but the rash of failures depleted the program's supply of spare grid rail modules and probes and removed one of the ion sources from regular operation. Fifteen years after their original fabrication, the ion source components were no longer commercially available. In 2001, a program was initiated to fabricate new grid rail modules, including new molybdenum grid rails, bellows, and stainless steel grid rail holders, as well as new Langmuir probes. In parallel, components removed from service due to leaks were to be repaired with new rails and bellows and returned to service. An overview of the root causes of the service failures is offered, details of the repair processes are described, and a summary and evaluation of the fabrication procedures for the new molybdenum rails, grid modules, and Langmuir probes are given.

  8. Transition and Interaction of Low-Frequency Magnetohydrodynamic Modes during Neutral Beam Injection Heating on HL-2A

    Science.gov (United States)

    Yu, Liming; Chen, Wei; Ding, Xuantong; Ji, Xiaoquan; Shi, Zhongbing; Yu, Deliang; Jiang, Min; Li, Dong; Li, Jiaxian; Li, Yonggao; Zhou, Yan; Ma, Rui; Li, Wei; Feng, Beibin; Huang, Yuan; Song, Xianming; Cao, Jianyong; Rao, Jun; Dong, Jiaqi; Xu, Min; Liu, Yi; Yan, Longwen; Yang, Qingwei; Xu, Yuhong; Duan, Xuru

    2017-02-01

    The strong fishbone mode (FB) and long-lived mode (LLM) have been observed during neutral beam injection (NBI) on the HL-2A tokamak. The FB and LLM can transit between each other. The LLM is identified as an internal kink mode (IKM) with the mode structure obtained using a newly developed electron cyclotron emission radiometer imaging (ECEI) system. The frequency of the LLM (fLLM) is higher than the toroidal rotation frequency (ft) near the q = 1 surface (r ˜ 10 cm). Experimental results show that the LLM is likely to be excited at a higher line-averaged electron density (bar{n}e) than that of the FB when the NBI power is fixed. It is found that the FB and its harmonic as seed magnetic islands can trigger tearing modes (TMs). The mode numbers for the low-frequency and high-frequency TMs are m/n = 2/1 and 3/2, respectively. By further investigation, it is found that there is an m/n = 1/1 IKM coexisting at the same time and with the same frequency as the m/n = 2/1 TM, and the m = 1 mode structure of the IKM in the radial cross section is obtained by the Bayesian tomography method utilizing soft X-ray arrays. The nonlinear coupling conditions are satisfied among the two TMs and IKM.

  9. Non-ideal operating conditions of the ion source prototype for the ITER neutral beam injector due to thermal deformation of the support structure.

    Science.gov (United States)

    Sartori, E; Pavei, M; Marcuzzi, D; Zaccaria, P

    2014-02-01

    The beam formation and acceleration of the ITER neutral beam injector will be studied in the full-scale ion source, Source for Production of Ions of Deuterium Extracted from a RF plasma (SPIDER). It will be able to sustain 40 A deuterium ion beam during 1-h pulses. The operating conditions of its multi-aperture electrodes will diverge from ideality, as a consequence of inhomogeneous heating and thermally induced deformations in the support structure of the extraction and acceleration grids, which operate at different temperatures. Meeting the requirements on the aperture alignment and distance between the grids with such a large number of apertures (1280) and the huge support structures constitute a challenge. Examination of the structure thermal deformation in transient and steady conditions has been carried out, evaluating their effect on the beam performance: the paper describes the analyses and the solutions proposed to mitigate detrimental effects.

  10. Non-ideal operating conditions of the ion source prototype for the ITER neutral beam injector due to thermal deformation of the support structure

    Science.gov (United States)

    Sartori, E.; Pavei, M.; Marcuzzi, D.; Zaccaria, P.

    2014-02-01

    The beam formation and acceleration of the ITER neutral beam injector will be studied in the full-scale ion source, Source for Production of Ions of Deuterium Extracted from a RF plasma (SPIDER). It will be able to sustain 40 A deuterium ion beam during 1-h pulses. The operating conditions of its multi-aperture electrodes will diverge from ideality, as a consequence of inhomogeneous heating and thermally induced deformations in the support structure of the extraction and acceleration grids, which operate at different temperatures. Meeting the requirements on the aperture alignment and distance between the grids with such a large number of apertures (1280) and the huge support structures constitute a challenge. Examination of the structure thermal deformation in transient and steady conditions has been carried out, evaluating their effect on the beam performance: the paper describes the analyses and the solutions proposed to mitigate detrimental effects.

  11. Non-ideal operating conditions of the ion source prototype for the ITER neutral beam injector due to thermal deformation of the support structure

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, E., E-mail: emanuele.sartori@igi.cnr.it; Pavei, M.; Marcuzzi, D.; Zaccaria, P. [Consorzio RFX, Euratom-ENEA Association, Corso Stati Uniti 4, 35127 Padova (Italy)

    2014-02-15

    The beam formation and acceleration of the ITER neutral beam injector will be studied in the full-scale ion source, Source for Production of Ions of Deuterium Extracted from a RF plasma (SPIDER). It will be able to sustain 40 A deuterium ion beam during 1-h pulses. The operating conditions of its multi-aperture electrodes will diverge from ideality, as a consequence of inhomogeneous heating and thermally induced deformations in the support structure of the extraction and acceleration grids, which operate at different temperatures. Meeting the requirements on the aperture alignment and distance between the grids with such a large number of apertures (1280) and the huge support structures constitute a challenge. Examination of the structure thermal deformation in transient and steady conditions has been carried out, evaluating their effect on the beam performance: the paper describes the analyses and the solutions proposed to mitigate detrimental effects.

  12. Comparison between the Counter Immunoelectrophoresis Test and Mouse Neutralization Test for the Detection of Antibodies against Rabies Virus in Dog Sera

    Directory of Open Access Journals (Sweden)

    Luzia Helena Queiroz da Silva

    2002-03-01

    Full Text Available The detection of rabies antibodies is extremely valuable for epidemiological studies, determination of immune status in man, animals, and for the diagnosis of the disease. Several serological procedures have been described for this purpose. The present study reports a comparison between counterimmunoelectrophoresis test (CIET and mouse neutralization test (MNT in the detection of antibodies against rabies virus from 212 serum samples of vaccinated dogs. The agreement between both techniques was 79.7% and a significative association was demonstrated. The correlation coefficients between MNT and the CIET titers was determined considering 88 samples showing positive results in both techniques [CIET = 2 and MNT = 5 (0.13 IU/ml] and resulted r² = 0.7926 (p < 0.001. The performance of CIET system was technically simple, cheap and rapid, and thereby it could be useful for serological monitoring of dog vaccination campaigns as well as for individual analysis.

  13. Investigation of a radio frequency-driven multicusp ion source of the diagnostic neutral beam for the Hanbit device at Korea Basic Science Institute

    Science.gov (United States)

    Yang, H. L.; Yoo, S. J.; Hwang, S. M.; Chung, K. H.

    2000-02-01

    A radio frequency-driven multicusp ion source has been fabricated and tested as a part of the development of a diagnostic neutral beam for the Hanbit magnetic mirror device [S. M. Hwang et al., Trans. Fusion Technol. 35, 99 (1999)]. Hydrogen plasma produced by a three-and-one-half turn antenna and rf power system with 2.5 kW, continuous wave (cw) 1.874 MHz was extracted through a single-aperture accel-decel system. The first results of the ion beam extraction experiments are described in this article.

  14. On the meniscus formation and the negative hydrogen ion extraction from ITER neutral beam injection relevant ion source

    Science.gov (United States)

    Mochalskyy, S.; Wünderlich, D.; Ruf, B.; Fantz, U.; Franzen, P.; Minea, T.

    2014-10-01

    The development of a large area (Asource,ITER = 0.9 × 2 m2) hydrogen negative ion (NI) source constitutes a crucial step in construction of the neutral beam injectors of the international fusion reactor ITER. To understand the plasma behaviour in the boundary layer close to the extraction system the 3D PIC MCC code ONIX is exploited. Direct cross checked analysis of the simulation and experimental results from the ITER-relevant BATMAN source testbed with a smaller area (Asource,BATMAN ≈ 0.32 × 0.59 m2) has been conducted for a low perveance beam, but for a full set of plasma parameters available. ONIX has been partially benchmarked by comparison to the results obtained using the commercial particle tracing code for positive ion extraction KOBRA3D. Very good agreement has been found in terms of meniscus position and its shape for simulations of different plasma densities. The influence of the initial plasma composition on the final meniscus structure was then investigated for NIs. As expected from the Child-Langmuir law, the results show that not only does the extraction potential play a crucial role on the meniscus formation, but also the initial plasma density and its electronegativity. For the given parameters, the calculated meniscus locates a few mm downstream of the plasma grid aperture provoking a direct NI extraction. Most of the surface produced NIs do not reach the plasma bulk, but move directly towards the extraction grid guided by the extraction field. Even for artificially increased electronegativity of the bulk plasma the extracted NI current from this region is low. This observation indicates a high relevance of the direct NI extraction. These calculations show that the extracted NI current from the bulk region is low even if a complete ion-ion plasma is assumed, meaning that direct extraction from surface produced ions should be present in order to obtain sufficiently high extracted NI current density. The calculated extracted currents, both ions

  15. Discharge Characteristics of Large-Area High-Power RF Ion Source for Positive and Negative Neutral Beam Injectors

    Science.gov (United States)

    Doo-Hee, Chang; Seung, Ho Jeong; Min, Park; Tae-Seong, Kim; Bong-Ki, Jung; Kwang, Won Lee; Sang Ryul, In

    2016-12-01

    A large-area high-power radio-frequency (RF) driven ion source was developed for positive and negative neutral beam injectors at the Korea Atomic Energy Research Institute (KAERI). The RF ion source consists of a driver region, including a helical antenna and a discharge chamber, and an expansion region. RF power can be transferred at up to 10 kW with a fixed frequency of 2 MHz through an optimized RF matching system. An actively water-cooled Faraday shield is located inside the driver region of the ion source for the stable and steady-state operations of high-power RF discharge. Plasma ignition of the ion source is initiated by the injection of argon-gas without a starter-filament heating, and the argon-gas is then slowly exchanged by the injection of hydrogen-gas to produce pure hydrogen plasmas. The uniformities of the plasma parameter, such as a plasma density and an electron temperature, are measured at the lowest area of the driver region using two RF-compensated electrostatic probes along the direction of the short-and long-dimensions of the driver region. The plasma parameters will be compared with those obtained at the lowest area of the expansion bucket to analyze the plasma expansion properties from the driver region to the expansion region. supported by the Ministry of Science, ICT and Future Planning of the Republic of Korea under the ITER Technology R&D Program, and National R&D Program Through the National Research Foundation of Korea (NRF) Funded by the Ministry of Science, ICT & Future Planning (NRF-2014M1A7A1A03045372)

  16. High Flux Neutral Beams

    Science.gov (United States)

    1990-03-31

    California, Department of Physics Irvine, California 92717 a jid C. E. Wiswall, S. L. Cartier and J. C. Leader McDonnell Douglas Corporation, St. Louis, MO...discharges on hydrocarbon containing polymers , C II and H I emission lines are expected to be the most prominent. In this case, the line width of the Ha...Department of Physics Irvine, California 92717 and S. L. Cartier and C. E. Wiswall McDonnell Douglas Corporation, St. Louis, MO 63166 ABSTRACT Conventional dc

  17. The neutral existence as a “saturated phenomenon”: describing the counter-experience of excess with Emmanuel Levinas and Jean-Luc Marion

    Directory of Open Access Journals (Sweden)

    Jaime Llorente Cardo

    2015-07-01

    Full Text Available The purpose of the present work is to show that the “there is” or the neuter existence which constitutes one of the most recurrent themes broached by Levinas in his early works of the late forties (De l´evasion, De l´existence à l´existant y Le temps et l´autre belongs thoroughly to the category described by Jean Luc Marion´s phenomenology of giveness under the name of “saturated phenomenon” or “paradox”. In order to make clear such belongingness, the four figures or attributes that define the excess of intuitive giveness are examinated according to their degree of coincidence with the way in which Levinas describes the singular experience of exposition to the neutrality of the existence without existents. This postulated identification between both elements means a potentially productive extension of the phenomenological horizon from the point of view of a possible overcoming of the traditional metaphysics.

  18. Damage-free top-down processes for fabricating two-dimensional arrays of 7 nm GaAs nanodiscs using bio-templates and neutral beam etching

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xuanyu; Huang, Chi-Hsien; Tsukamoto, Rikako; Samukawa, Seiji [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Mortemousque, Pierre-Andre; Itoh, Kohei M; Ohno, Yuzo, E-mail: samukawa@ifs.tohoku.ac.jp [Japan Science and Technology Agency, CREST, 5 Sanbancho, Chiyoda, Tokyo 102-0075 (Japan)

    2011-09-07

    The first damage-free top-down fabrication processes for a two-dimensional array of 7 nm GaAs nanodiscs was developed by using ferritin (a protein which includes a 7 nm diameter iron core) bio-templates and neutral beam etching. The photoluminescence of GaAs etched with a neutral beam clearly revealed that the processes could accomplish defect-free etching for GaAs. In the bio-template process, to remove the ferritin protein shell without thermal damage to the GaAs, we firstly developed an oxygen-radical treatment method with a low temperature of 280 deg. C. Then, the neutral beam etched the defect-free nanodisc structure of the GaAs using the iron core as an etching mask. As a result, a two-dimensional array of GaAs quantum dots with a diameter of {approx} 7 nm, a height of {approx} 10 nm, a high taper angle of 88 deg. and a quantum dot density of more than 7 x 10{sup 11} cm{sup -2} was successfully fabricated without causing any damage to the GaAs.

  19. Effects of neutral particle beam on nano-crystalline silicon thin films, with application to thin film transistor backplane for flexible active matrix organic light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jin Nyoung; Song, Byoung Chul; Lee, Dong Hyeok [Dept. of Display and Semiconductor Physics, Korea University, Chungnam (Korea, Republic of); Yoo, Suk Jae; Lee, Bonju [National Fusion Research Institute, 52, Yuseong-Gu, Deajeon, 305-333 (Korea, Republic of); Hong, MunPyo, E-mail: goodmoon@korea.ac.kr [Dept. of Display and Semiconductor Physics, Korea University, Chungnam (Korea, Republic of)

    2011-08-01

    A novel deposition process for nano-crystalline silicon (nc-Si) thin films was developed using neutral beam assisted chemical vapor deposition (NBaCVD) technology for the application of the thin film transistor (TFT) backplane of flexible active matrix organic light emitting diode (AMOLED). During the formation of a nc-Si thin film, the energetic particles enhance nano-sized crystalline rather microcrystalline Si in thin films. Neutral Particle Beam (NPB) affects the crystallinity in two ways: (1) NPB energy enhances nano-crystallinity through kinetic energy transfer and chemical annealing, and (2) heavier NPB (such as Ar) induces damage and amorphization through energetic particle impinging. Nc-Si thin film properties effectively can be changed by the reflector bias. As increase of NPB energy limits growing the crystalline, the performance of TFT supports this NPB behavior. The results of nc-Si TFT by NBaCVD demonstrate the technical potentials of neutral beam based processes for achieving high stability and reduced leakage in TFT backplanes for AMOLEDs.

  20. Direct Measurements of Space-Charge-Potential in High Intensity H- Beam with Laser Based Photo Neutralization Method

    CERN Document Server

    Lee, S; Ikegami, M; Toyama, T

    2005-01-01

    Transverse profiles of H- beams can be observed by scanning a laser wire across the ion beam and detect the pulse of photo detached electrons. In addition, laser based photo neutralization method have a capability of direct space-charge-potential measurement by investigate the energy distribution of collected electrons. The kinetic energy of photo detached electron corresponds to the ion velocity and space potential at stripped location. The space-charge-potential in H- beam can be measured by scanning the bias potential of repeller grid in front of Faraday cup. In this paper, an available method to observe the space-charge-potential and preliminary experimental results with Nd:YAG laser in KEK DTL1 (J-PARC) are described.

  1. Development of a long-pulse (30-s), high-energy (120-keV) ion source for neutral-beam applications

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.C.; Barber, G.C.; Blue, C.W.

    1983-01-01

    Multimegawatt neutral beams of hydrogen or deuterium atoms are needed for fusion machine applications such as MFTB-B, TFTR-U, DIII-U, and FED (INTOR or ETR). For these applications, a duoPIGatron ion source is being developed to produce high-brightness deuterium beams at a beam energy of approx. 120 keV for pulse lengths up to 30 s. A long-pulse plasma generator with active water cooling has been operated at an arc level of 1200 A with 30-s pulse durations. The plasma density and uniformity are sufficient for supplying a 60-A beam of hydrogen ions to a 13- by 43-cm accelerator. A 10- by 25-cm tetrode accelerator has been operated to form 120-keV hydrogen ion beams. Using the two-dimensional (2-D) ion extraction code developed at Oak Ridge National Laboratory (ORNL), a 13- by 43-cm tetrode accelerator has been designed and is being fabricated. The aperture shapes of accelerator grids are optimized for 120-keV beam energy.

  2. Effects of errors in velocity tilt on maximum longitudinal compression during neutralized drift compression of intense beam pulses: I. general description

    Energy Technology Data Exchange (ETDEWEB)

    Kaganovich, Igor D., E-mail: ikaganov@pppl.gov [Plasma Physics Laboratory, Princeton University, Princeton, NJ 08543 (United States); Massidda, Scott; Startsev, Edward A.; Davidson, Ronald C. [Plasma Physics Laboratory, Princeton University, Princeton, NJ 08543 (United States); Vay, Jean-Luc [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Friedman, Alex [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States)

    2012-06-21

    Neutralized drift compression offers an effective means for particle beam pulse compression and current amplification. In neutralized drift compression, a linear longitudinal velocity tilt (head-to-tail gradient) is applied to the non-relativistic beam pulse, so that the beam pulse compresses as it drifts in the focusing section. The beam current can increase by more than a factor of 100 in the longitudinal direction. We have performed an analytical study of how errors in the velocity tilt acquired by the beam in the induction bunching module limit the maximum longitudinal compression. It is found that the compression ratio is determined by the relative errors in the velocity tilt. That is, one-percent errors may limit the compression to a factor of one hundred. However, a part of the beam pulse where the errors are small may compress to much higher values, which are determined by the initial thermal spread of the beam pulse. It is also shown that sharp jumps in the compressed current density profile can be produced due to overlaying of different parts of the pulse near the focal plane. Examples of slowly varying and rapidly varying errors compared to the beam pulse duration are studied. For beam velocity errors given by a cubic function, the compression ratio can be described analytically. In this limit, a significant portion of the beam pulse is located in the broad wings of the pulse and is poorly compressed. The central part of the compressed pulse is determined by the thermal spread. The scaling law for maximum compression ratio is derived. In addition to a smooth variation in the velocity tilt, fast-changing errors during the pulse may appear in the induction bunching module if the voltage pulse is formed by several pulsed elements. Different parts of the pulse compress nearly simultaneously at the target and the compressed profile may have many peaks. The maximum compression is a function of both thermal spread and the velocity errors. The effects of the

  3. Nonlinear simulations of Neutral-beam-driven Compressional Alfvén Eigenmodes / Kinetic Alfvén Waves in NSTX

    Science.gov (United States)

    Belova, Elena; Gorelenkov, N. N.; Crocker, N. A.; Lestz, J. B.; Fredrickson, E. D.; Tang, S.

    2016-10-01

    Results of 3D nonlinear simulations of neutral-beam-driven compressional Alfvén eigenmodes (CAEs) in the National Spherical Torus Experiment (NSTX) are presented. Hybrid MHD-particle simulations for the H-mode NSTX discharge (shot 141398) using the HYM code show unstable CAE modes for a range of toroidal mode numbers, n =4-9, and frequencies below the ion cyclotron frequency. It is found that the essential feature of CAEs is their coupling to kinetic Alfven wave (KAW) that occurs on the high-field side at the Alfven resonance location. Nonlinear simulations demonstrate that CAEs can channel the energy of the beam ions from the injection region near the magnetic axis to the location of the resonant mode conversion at the edge of the beam density profile. This mechanism provides an alternative explanation to the observed reduced heating of the plasma core in the NSTX. A set of nonlinear simulations show that the CAE instability saturates due to nonlinear particle trapping, and a large fraction of beam energy can be transferred to several unstable CAEs of relatively large amplitudes and absorbed at the resonant location. Absorption rate shows a strong scaling with the beam power. This research was supported by the U.S. DOE contract # DE-AC02-09CH11466.

  4. Simultaneous feedback control of plasma rotation and stored energy on NSTX-U using neoclassical toroidal viscosity and neutral beam injection

    Science.gov (United States)

    Goumiri, I. R.; Rowley, C. W.; Sabbagh, S. A.; Gates, D. A.; Boyer, M. D.; Gerhardt, S. P.; Kolemen, E.; Menard, J. E.

    2017-05-01

    A model-based feedback system is presented enabling the simultaneous control of the stored energy through βn and the toroidal rotation profile of the plasma in National Spherical Torus eXperiment Upgrade device. Actuation is obtained using the momentum from six injected neutral beams and the neoclassical toroidal viscosity generated by applying three-dimensional magnetic fields. Based on a model of the momentum diffusion and torque balance, a feedback controller is designed and tested in closed-loop simulations using TRANSP, a time dependent transport analysis code, in predictive mode. Promising results for the ongoing experimental implementation of controllers are obtained.

  5. Time average neutralized migma: A colliding beam/plasma hybrid physical state as aneutronic energy source — A review

    Science.gov (United States)

    Maglich, Bogdan C.

    1988-08-01

    A D + beam of kinetic energy Ti = 0.7 MeV was stored in a "simple mirror" magnetic field as self-colliding orbits or migma and neutralized by ambient, oscillating electrons whose bounce frequencies were externally controlled. Space charge density was exceeded by an order of magnitude without instabilities. Three nondestructive diagnostic methods allowed measurements of ion orbit distribution, ion storage times, ion energy distribution, nuclear reaction rate, and reaction product spectrum. Migma formed a disc 20 cm in diameter and 0.5 cm thick. Its ion density was sharply peaked in the center; the ion-to-electron temperature ratio was TiTe ˜ 10 3; ion-electron temperature equilibrium was never reached. The volume average and central D + density were n = 3.2 × 10 9 cm -3 and nc = 3 × 10 10 cm -3 respectively, compared to the space charge limit density nsc = 4 × 10 8 cm -3. The energy confinement time was τc = 20-30 s, limited by the change exchange reactions with the residual gas in the vacuum (5 × 10 -9 Torr). The ion energy loss rate was 1.4 keV/s. None of the instabilities that were observed in mirrors at several orders of magnitude lower density occurred. The proton energy spectrum for dd + d → T + p + 4 MeV shows that dd collided at an average crossing angle of 160°. Evidence for exponential density buildup has also been observed. Relative to Migma III results and measured in terms of the product of ion energy E, density n, and confinement time τ, device performance was improved by a factor of 500. Using the central fast ion density, we obtained the triple product: Tnτ ≅ 4 × 10 14 keV s cm -3, which is greater than that of the best fusion devices. The luminosity (collision rate per unit cross section) was ˜ 10 29 cm -2s -1, with o.7 A ion current through the migma center. The stabilizing features of migma are: (1) large Larmor radius; (2) small canonical angular momentum; (3) short axial length z (disc shape); (4) nonadiabatic motions in r and z

  6. Measurement of high-Q{sup 2} neutral current deep inelastic e{sup +}p scattering cross sections with a longitudinally polarised positron beam at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (Poland). Faculty of Physics and Applied Computer Science] [and others; Collaboration: ZEUS Collaboration

    2012-08-15

    Measurements of neutral current cross sections for deep inelastic scattering in e{sup +}p collisions at HERA with a longitudinally polarised positron beam are presented. The single-differential cross-sections d{sigma}/dQ{sup 2}, d{sigma}/dx and d{sigma}/dy and the reduced cross-section {sigma} were measured in the kinematic region Q{sup 2}>185 GeV{sup 2} and y<0.9, where Q{sup 2} is the four-momentum transfer squared, x the Bjorken scaling variable, and y the inelasticity of the interaction. The measurements were performed separately for positively and negatively polarised positron beams. The measurements are based on an integrated luminosity of 135.5 pb{sup -1} collected with the ZEUS detector in 2006 and 2007 at a centre-of-mass energy of 318 GeV. The structure functions F{sub 3} and F{sup {gamma}Z}{sub 3} were determined by combining the e{sup +}p results presented in this paper with previously published e{sup -}p neutral current results. The asymmetry parameter A{sup +} is used to demonstrate the parity violation predicted in electroweak interactions. The measurements are well described by the predictions of the Standard Model.

  7. Measurement of high-Q{sup 2} neutral current deep inelastic e{sup -}p scattering cross sections with a longitudinally polarised electron beam at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)

    2008-12-15

    Measurements of the neutral current cross sections for deep inelastic scattering in e{sup -}p collisions at HERA with a longitudinally polarised electron beam are presented. The single-differential cross-sections d{sigma}/dQ{sup 2}, d{sigma}/dx and d{sigma}/dy and the double-differential cross sections in Q{sup 2} and x are measured in the kinematic region y < 0.9 and Q{sup 2} > 185GeV{sup 2} for both positively and negatively polarised electron beams and for each polarisation state separately. The measurements are based on an integrated luminosity of 169.9 pb{sup -1} taken with the ZEUS detector in 2005 and 2006 at a centre-of-mass energy of 318GeV. The structure functions xF{sub 3} and xF{sub 3}{sup {gamma}}{sup Z} are determined by combining the e{sup -}p results presented in this paper with previously measured e{sup +}p neutral current data. The asymmetry parameter A{sup -} is used to demonstrate the parity violating effects of electroweak interactions at large spacelike photon virtuality. The measurements agree well with the predictions of the Standard Model. (orig.)

  8. Transient Enhancement ('Spike-on-Tail') Observed on Neutral-Beam-Injected Energetic Ion Spectra Using the E||B Neutral Particle Analyzer in the National Spherical Torus Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Medley, S. S. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Gorelenkov, N. N. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Bell, R. E. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Fredrickson, E. D. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Gerhardt, S. P. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); LeBlanc, B. P. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Podesta, M. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Roquemore, A. L. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    2010-06-01

    An increase of up to four-fold in the E||B Neutral Particle Analyzer (NPA) charge exchange neutral flux localized at the Neutral Beam (NB) injection full energy is observed in the National Spherical Torus Experiment (NSTX). Termed the High-Energy Feature (HEF), it appears on the NB-injected energetic ion spectrum only in discharges where tearing or kink-type modes (f < 10 kHz) are absent, TAE activity (f ~ 10-150 kHz) is weak (δBrms < 75 mGauss) and CAE/GAE activity (f ~ 400 – 1200 kHz) is robust. The feature exhibits a growth time of ~ 20 - 80 ms and occasionally develops a slowing down distribution that continues to evolve over periods of 100's of milliseconds, a time scale long compared with the typical ~ 10's ms equilibration time of the NB injected particles. The HEF is observed only in H-mode (not L-mode) discharges with injected NB power of 4 MW or greater and in the field pitch range v||/v ~ 0.7 – 0.9; i.e. only for passing (never trapped) energetic ions. The HEF is suppressed by vessel conditioning using lithium deposition at rates ~ 100 mg/shot, a level sufficient to suppress ELM activity. Increases of ~ 10 - 30 % in the measured neutron yield and total stored energy are observed to coincide with the feature along with broadening of measured Te(r), Ti(r) and ne(r) profiles. However, TRANSP analysis shows that such increases are driven by plasma profile changes and not the HEF phenomenon itself. Though a definitive mechanism has yet to be developed, the HEF appears to be caused by a form of TAE/CAE wave-particle interaction that distorts of the NB fast ion distribution in phase space.

  9. NA48/1. A high sensitivity investigation of $K_{\\rm S}$ and neutral hyperon decays using a modified $K_{\\rm S}$ beam

    CERN Multimedia

    Kalmus, G E; Lazzeroni, C; Munday, D J; Slater, M W; Wotton, S; Monnier, E; Swallow, E C; Winston, R; Gudzovskiy, E; Gurev, D; Kuz'Min, N; Madigozhin, D; Molokanova, N; Potrebenikov, Y; Rubin, P D; Walker, A; Dabrowski, A E; Cotta Ramusino, A; Damiani, C; Gianoli, A; Savrie, M; Scarpa, M; Wahl, H; Bizzeti, A; Calvetti, M; Iacopini, E; Lenti, M; Veltri, M; Bocquet, G; Ceccucci, A; Gatignon, L; Gonidec, A; Anvar, S; Cheze, J-B; De Beer, M; Debu, P; Gouge, G; Le Provost, H; Mandjavidze, I; Marel, G; Mazzucato, E; Peyaud, B; Vallage, B; Behler, M; Eppard, K; Kleinknecht, K; Masetti, L; Moosbrugger, U; Morales Morales, C; Wanke, R; Winhart, A; Anzivino, G; Cenci, P; Imbergamo, E; Nappi, A; Pepe, M S; Petrucci, M C; Piccini, M; Valdata, M; Cerri, C; Collazuol, G; Costantini, F; Giudici, S; Lamanna, G; Mannelli, I; Pierazzini, G; Sozzi, M; Holder, M; Maier, A; Ziolkowski, M; Cartiglia, N; Menichetti, E; Pastrone, N; Dibon, H; Jeitler, M; Neuhofer, G; Pernicka, M; Taurok, A

    2002-01-01

    %NA48/1 The experiment performs a search for rare $K_{\\rm S}$ and neutral hyperon decays. A neutral beam is produced by 400 GeV protons striking a beryllium target. About 1/3 of the produced $K_{\\rm S}$ particles live long enough to enter the decay region 6m downstream of the target. The experiment aims to an exposure of about $3 \\times 10^{10}$ neutral kaon decays. The experimental apparatus is based on the existing NA48 detector, with upgraded read-out systems. Charged particles are reconstructed by a magnetic spectrometer; photons are measured by a liquid krypton calorimeter (LKr). Among the most interesting decay decay modes there are the $\\pi^0 e^+ e^-$, $ 3 \\pi^0$, and $\\gamma \\gamma$. A measurement of the $ K_{\\rm S} \\rightarrow \\pi^0 e^+ e^-$channel, or at least a precise upper limit, will bound the indirect CP violating term in the decay $ K_{\\rm L} \\rightarrow \\pi^0 e^+ e^-$. The branching ratio for the $K_{\\rm S}$ mode the cannot be accurately predicted and therefore a measurement for this decay is...

  10. Spectroscopic characterization of H 2 and D 2 helicon plasmas generated by a resonant antenna for neutral beam applications in fusion

    Science.gov (United States)

    Marini, C.; Agnello, R.; Duval, B. P.; Furno, I.; Howling, A. A.; Jacquier, R.; Karpushov, A. N.; Plyushchev, G.; Verhaegh, K.; Guittienne, Ph.; Fantz, U.; Wünderlich, D.; Béchu, S.; Simonin, A.

    2017-03-01

    A new generation of neutral beam systems will be required in future fusion reactors, such as DEMO, able to deliver high power (up to 50 MW) with high (800 keV or higher) neutral energy. Only negative ion beams may be able to attain this performance, which has encouraged a strong research focus on negative ion production from both surface and volumetric plasma sources. A novel helicon plasma source, based on the resonant birdcage network antenna configuration, is currently under study at the Swiss Plasma Centre before installation on the Cybele negative ion source at the Institute for Magnetic Fusion Research, CEA, Cadarache, France. This source is driven by up to 10 kW at 13.56 MHz, and is being tested on a linear resonant antenna ion device. Passive spectroscopic measurements of the first three Balmer lines α, β and γ and of the Fulcher-α bands were performed with an f/2 spectrometer, for both hydrogen and deuterium. Multiple viewing lines and an absolute intensity calibration were used to determine the plasma radiance profile, with a spatial resolution  emissivity profile for each emission line for cylindrical symmetry, which was experimentally confirmed. An uncertainty estimate of the inverted profiles was performed using a Monte Carlo approach. Finally, a radiofrequency-compensated Langmuir probe was inserted to measured the electron temperature and density profiles. The absolute line emissivities are interpreted using the collisional-radiative code YACORA which estimates the degree of dissociation and the distribution of the atomic and molecular species, including the negative ion density. This paper reports the results of a power scan up to 5 kW in conditions satisfying Cybele requirements for the plasma source, namely a low neutral pressure, p≤slant 0.3 Pa and magnetic field B≤slant 150 G.

  11. Measurements of the neutral current e{sup {+-}}p cross sections using longitudinally polarised lepton beams at HERA II

    Energy Technology Data Exchange (ETDEWEB)

    Nikiforov, A.

    2007-01-18

    This thesis presents inclusive e{sup {+-}}p single and double differential cross sections for neutral current deep inelastic scattering measured as functions of the four-momentum transfer squared Q{sup 2} and the Bjorken variable x in interactions of longitudinally polarised leptons with unpolarised protons using the H1 detector at HERA II. An overview of the phenomenology of deep inelastic scattering is given and the experimental apparatus as well as the measurement and analysis procedures are described. The analysis is based on e{sup +}p data taken in 2003-04 and e{sup -}p data taken in 2005 at a centre-of-mass energy of {radical}(s)=318 GeV, with integrated luminosities of 47.6 pb{sup -1} and 98.4 pb{sup -1} for the e{sup +}p and e{sup -}p samples, respectively. The cross sections are measured in the range of 200neutral current interactions and to determine the structure function xF{sub 3}. The new HERA II data are combined together with previously published data from HERA I to determine the structure function xF{sub 3} with improved precision. Furthermore, this measurement is combined with the corresponding ZEUS measurement to provide the most accurate measurement of the interference structure function xF{sup {gamma}}{sup Z}{sub 3}, which is sensitive to the valence quark distributions down to low values of x. The data on polarised cross section asymmetries A{sup {+-}} are also combined with the ZEUS data. This leads to the first observation of parity violation in neutral current e{sup {+-}}p scattering at distances down to 10{sup -18} m. The data are well described by the Standard Model predictions. (orig.)

  12. Precision determination of the lifetime of the neutral pion

    CERN Multimedia

    2002-01-01

    The experiment aims at a determination of the lifetime of the neutral pion with an accuracy of 1\\%, as against at present 5\\% for the best measurement by the indirect, Primakoff method, and 18\\% by a direct measurement. \\\\\\\\2 gold foils with different separations are traversed by the extracted proton beam to the High Intensity Area. Positive particles of 160 GeV/c momentum from this target are transported by the H6 beam to the North Area. The electron component is separated from heavier particles by synchrotron losses in the bending magnets, and is further identified by a lead glass Cerenkov counter, in coincidence with scintillation counters (Fig. 1).\\\\\\\\ The electron flux from the double foil target depends on the distance between the foils, since for small separations the neutral pions will have to decay before electrons can be materialised by the decay $\\gamma$ rays.\\\\\\\\ The average momentum of neutral pions from a 400 GeV pN reaction, giving a 160 GeV/c electron, is about 250 GeV/c, and the corresponding...

  13. Physics design of a 100 keV acceleration grid system for the diagnostic neutral beam for international tokamak experimental reactor.

    Science.gov (United States)

    Singh, M J; De Esch, H P L

    2010-01-01

    This paper describes the physics design of a 100 keV, 60 A H(-) accelerator for the diagnostic neutral beam (DNB) for international tokamak experimental reactor (ITER). The accelerator is a three grid system comprising of 1280 apertures, grouped in 16 groups with 80 apertures per beam group. Several computer codes have been used to optimize the design which follows the same philosophy as the ITER Design Description Document (DDD) 5.3 and the 1 MeV heating and current drive beam line [R. Hemsworth, H. Decamps, J. Graceffa, B. Schunke, M. Tanaka, M. Dremel, A. Tanga, H. P. L. De Esch, F. Geli, J. Milnes, T. Inoue, D. Marcuzzi, P. Sonato, and P. Zaccaria, Nucl. Fusion 49, 045006 (2009)]. The aperture shapes, intergrid distances, and the extractor voltage have been optimized to minimize the beamlet divergence. To suppress the acceleration of coextracted electrons, permanent magnets have been incorporated in the extraction grid, downstream of the cooling water channels. The electron power loads on the extractor and the grounded grids have been calculated assuming 1 coextracted electron per ion. The beamlet divergence is calculated to be 4 mrad. At present the design for the filter field of the RF based ion sources for ITER is not fixed, therefore a few configurations of the same have been considered. Their effect on the transmission of the electrons and beams through the accelerator has been studied. The OPERA-3D code has been used to estimate the aperture offset steering constant of the grounded grid and the extraction grid, the space charge interaction between the beamlets and the kerb design required to compensate for this interaction. All beamlets in the DNB must be focused to a single point in the duct, 20.665 m from the grounded grid, and the required geometrical aimings and aperture offsets have been calculated.

  14. Physics design of a 100 keV acceleration grid system for the diagnostic neutral beam for international tokamak experimental reactor

    Science.gov (United States)

    Singh, M. J.; De Esch, H. P. L.

    2010-01-01

    This paper describes the physics design of a 100 keV, 60 A H- accelerator for the diagnostic neutral beam (DNB) for international tokamak experimental reactor (ITER). The accelerator is a three grid system comprising of 1280 apertures, grouped in 16 groups with 80 apertures per beam group. Several computer codes have been used to optimize the design which follows the same philosophy as the ITER Design Description Document (DDD) 5.3 and the 1 MeV heating and current drive beam line [R. Hemsworth, H. Decamps, J. Graceffa, B. Schunke, M. Tanaka, M. Dremel, A. Tanga, H. P. L. De Esch, F. Geli, J. Milnes, T. Inoue, D. Marcuzzi, P. Sonato, and P. Zaccaria, Nucl. Fusion 49, 045006 (2009)]. The aperture shapes, intergrid distances, and the extractor voltage have been optimized to minimize the beamlet divergence. To suppress the acceleration of coextracted electrons, permanent magnets have been incorporated in the extraction grid, downstream of the cooling water channels. The electron power loads on the extractor and the grounded grids have been calculated assuming 1 coextracted electron per ion. The beamlet divergence is calculated to be 4 mrad. At present the design for the filter field of the RF based ion sources for ITER is not fixed, therefore a few configurations of the same have been considered. Their effect on the transmission of the electrons and beams through the accelerator has been studied. The OPERA-3D code has been used to estimate the aperture offset steering constant of the grounded grid and the extraction grid, the space charge interaction between the beamlets and the kerb design required to compensate for this interaction. All beamlets in the DNB must be focused to a single point in the duct, 20.665 m from the grounded grid, and the required geometrical aimings and aperture offsets have been calculated.

  15. Emergence of Kinetic Behavior in Streaming Ultracold Neutral Plasmas

    CERN Document Server

    McQuillen, P; Bradshaw, S; Killian, T C

    2014-01-01

    We create streaming ultracold neutral plasmas by tailoring the photoionizing laser beam that creates the plasma. By varying the electron temperature, we control the relative velocity of the streaming populations, and, in conjunction with variation of the plasma density, this controls the ion collisionality of the colliding streams. Laser-induced fluorescence is used to map the spatially resolved density and velocity distribution function for the ions. We identify the lack of local thermal equilibrium and distinct populations of interpenetrating, counter-streaming ions as signatures of kinetic behavior. Experimental data is compared with results from a one-dimensional, two-fluid numerical simulation.

  16. Modeling of fast neutral-beam-generated ion effects on MHD-spectroscopic observations of resistive wall mode stability in DIII-D plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Turco, F., E-mail: turcof@fusion.gat.com; Hanson, J. M.; Navratil, G. A. [Columbia University, 116th and Broadway, New York, New York 10027 (United States); Turnbull, A. D. [General Atomics, PO Box 85608, San Diego, California 92186-5608 (United States)

    2015-02-15

    Experiments conducted at DIII-D investigate the role of drift kinetic damping and fast neutral beam injection (NBI)-ions in the approach to the no-wall β{sub N} limit. Modelling results show that the drift kinetic effects are significant and necessary to reproduce the measured plasma response at the ideal no-wall limit. Fast neutral-beam ions and rotation play important roles and are crucial to quantitatively match the experiment. In this paper, we report on the model validation of a series of plasmas with increasing β{sub N}, where the plasma stability is probed by active magnetohydrodynamic (MHD) spectroscopy. The response of the plasma to an externally applied field is used to probe the stable side of the resistive wall mode and obtain an indication of the proximity of the equilibrium to an instability limit. We describe the comparison between the measured plasma response and that calculated by means of the drift kinetic MARS-K code [Liu et al., Phys. Plasmas 15, 112503 (2008)], which includes the toroidal rotation, the electron and ion drift-kinetic resonances, and the presence of fast particles for the modelled plasmas. The inclusion of kinetic effects allows the code to reproduce the experimental results within ∼13% for both the amplitude and phase of the plasma response, which is a significant improvement with respect to the undamped MHD-only model. The presence of fast NBI-generated ions is necessary to obtain the low response at the highest β{sub N} levels (∼90% of the ideal no-wall limit). The toroidal rotation has an impact on the results, and a sensitivity study shows that a large variation in the predicted response is caused by the details of the rotation profiles at high β{sub N}.

  17. Atomic Diffusion in Cu/Si (111) and Cu/SiO2/Si (111) Systems by Neutral Cluster Beam Deposition

    Institute of Scientific and Technical Information of China (English)

    CAO Bo; LI Gong-Ping; CHEN Xi-Meng; CHO Seong-Jin; KIM Hee

    2008-01-01

    @@ The Cu films are deposited on two kinds of p-type Si (111) substrates by ionized cluster beam (ICB) technique.The interface reaction and atomic diffusion of Cu/Si (111) and Cu/SiO2/Si (111) systems are studied at different annealing temperatures by x-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS). Some significant results are obtained: For the Cu/Si (111) samples prepared by neutral clusters, the interdiffusion of Cu and Si atoms occurs when annealed at 230℃. The diffusion coefficients of the samples annealed at 230℃and 500℃ are 8.5 × 10-15 cm2.s-1 and 3.0 × 10-14 cm2.s-1, respectively. The formation of the copper-silicide phase is observed by XRD, and its intensity becomes stronger with the increase of annealing temperature. For the Cu/SiO2/Si (111) samples prepared by neutral clusters, the interdiffusion of Cu and Si atoms occurs and copper silicides are formed when annealed at 450℃. The diffusion coefficients of Cu in Si are calculated to be 6.0 × 10-16 cm2.s-1 at 450℃, due to the fact that the existence of the SiO2 layer suppresses the interdiffusion of Cu and Si.

  18. Characteristics of a high-power RF source of negative hydrogen ions for neutral beam injection into controlled fusion devices

    Science.gov (United States)

    Abdrashitov, G. F.; Belchenko, Yu. I.; Gusev, I. A.; Ivanov, A. A.; Kondakov, A. A.; Sanin, A. L.; Sotnikov, O. Z.; Shikhovtsev, I. V.

    2017-01-01

    An injector of hydrogen atoms with an energy of 0.5-1 MeV and equivalent current of up to 1.5 A for purposes of controlled fusion research is currently under design at the Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences. Within this project, a multiple-aperture RF surface-plasma source of negative hydrogen ions is designed. The source design and results of experiments on the generation of a negative ion beam with a current of >1 A in the long-pulse mode are presented.

  19. Classical physics impossibility of magnetic fusion reactor with neutral beam injection at thermonuclear energies below 200 KeV

    Science.gov (United States)

    Maglich, Bogdan; Hester, Timothy; Vaucher, Alexander

    2016-10-01

    Lawson criterion was specifically derived for inertial fusion and DT gas of stable lifetime without ions and magnetic fields. It was revised with realistic parametrers. To account for the losses of unstable ions against neutralization with lifetime τ, n (t) = nτ [ 1 - exp (- t / - tτ τ) ] -> nτ for τ CT resonance regime below critical energy To, τ 10-5 , and Lawson requirement ntL 1021 i.e. not realistic. Luminosity (reaction rate for σ = 1) is that of two unstable particles each with lifetime τ: L =n2(t)v12 =n2t2v12 . In subcritical regime, L =10-10n2 forn =1014cm-3 , v 109 cms-1 = L =1027 . Which is negligible and implies a negative power flow reactor. But above T0 , atTD = 725 KeV , τ = 20 s was observed implying L =1039 i.e. massive fusion energy production.

  20. Counter support for WA35

    CERN Multimedia

    1977-01-01

    This assembly was equipped with 78 counters, each consisting of a lucite cone, to produce Cerenkov light, and a CsI scintillator plate of 3 mm thickness glued on the face of the cone. The experiment WA35 was set-up in the s1 beam (West Hall) by the Darmstadt-Heidelberg-Virginia-Warsaw Collaboration to measure angular distributions and multiplicities of pions and recoil protons produced by hadrons interacting in nuclei. (See Annual Report 1976 p. 39)

  1. Distributed performance counters

    Science.gov (United States)

    Davis, Kristan D; Evans, Kahn C; Gara, Alan; Satterfield, David L

    2013-11-26

    A plurality of first performance counter modules is coupled to a plurality of processing cores. The plurality of first performance counter modules is operable to collect performance data associated with the plurality of processing cores respectively. A plurality of second performance counter modules are coupled to a plurality of L2 cache units, and the plurality of second performance counter modules are operable to collect performance data associated with the plurality of L2 cache units respectively. A central performance counter module may be operable to coordinate counter data from the plurality of first performance counter modules and the plurality of second performance modules, the a central performance counter module, the plurality of first performance counter modules, and the plurality of second performance counter modules connected by a daisy chain connection.

  2. View of the VO prototype made of two sectors of scintillating counters. WLS fibers embedded within connectors appear in green color. Beams of optical fibers inside black sheath collect and transport the emitted light to photo-multipliers a few meters apart.

    CERN Multimedia

    2004-01-01

    View of the VO prototype made of two sectors of scintillating counters. WLS fibers embedded within connectors appear in green color. Beams of optical fibers inside black sheath collect and transport the emitted light to photo-multipliers a few meters apart.

  3. Manufacturing, assembly and tests of SPIDER Vacuum Vessel to develop and test a prototype of ITER neutral beam ion source

    Energy Technology Data Exchange (ETDEWEB)

    Zaccaria, Pierluigi, E-mail: pierluigi.zaccaria@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete S.p.A.), Padova (Italy); Valente, Matteo; Rigato, Wladi; Dal Bello, Samuele; Marcuzzi, Diego; Agostini, Fabio Degli; Rossetto, Federico; Tollin, Marco [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete S.p.A.), Padova (Italy); Masiello, Antonio [Fusion for Energy F4E, Barcelona (Spain); Corniani, Giorgio; Badalocchi, Matteo; Bettero, Riccardo; Rizzetto, Dario [Ettore Zanon S.p.A., Schio (VI) (Italy)

    2015-10-15

    Highlights: • The SPIDER experiment aims to qualify and optimize the ion source for ITER injectors. • The large SPIDER Vacuum Vessel was built and it is under testing at the supplier. • The main working and assembly steps for production are presented in the paper. - Abstract: The SPIDER experiment (Source for the Production of Ions of Deuterium Extracted from an RF plasma) aims to qualify and optimize the full size prototype of the negative ion source foreseen for MITICA (full size ITER injector prototype) and the ITER Heating and Current Drive Injectors. Both SPIDER and MITICA experiments are presently under construction at Consorzio RFX in Padova (I), with the financial support from IO (ITER Organization), Fusion for Energy, Italian research institutions and contributions from Japan and India Domestic Agencies. The vacuum vessel hosting the SPIDER in-vessel components (Beam Source and calorimeters) has been manufactured, assembled and tested during the last two years 2013–2014. The cylindrical vessel, about 6 m long and 4 m in diameter, is composed of two cylindrical modules and two torispherical lids at the ends. All the parts are made by AISI 304 L stainless steel. The possibility of opening/closing the vessel for monitoring, maintenance or modifications of internal components is guaranteed by bolted junctions and suitable movable support structures running on rails fixed to the building floor. A large number of ports, about one hundred, are present on the vessel walls for diagnostic and service purposes. The main working steps for construction and specific technological issues encountered and solved for production are presented in the paper. Assembly sequences and tests on site are furthermore described in detail, highlighting all the criteria and requirements for correct positioning and testing of performances.

  4. Neutral particle lithography

    Science.gov (United States)

    Craver, Barry Paul

    Neutral particle lithography (NPL) is a high resolution, proximity exposure technique where a broad beam of energetic neutral particles floods a stencil mask and transmitted beamlets transfer the mask pattern to resist on a substrate, such that each feature is printed in parallel, rather than in the serial manner of electron beam lithography. It preserves the advantages of ion beam lithography (IBL), including extremely large depth-of-field, sub-5 nm resist scattering, and the near absence of diffraction, yet is intrinsically immune to charge-related artifacts including line-edge roughness and pattern placement errors due to charge accumulation on the mask and substrate. In our experiments, a neutral particle beam is formed by passing an ion beam (e.g., 30 keV He+) through a high pressure helium gas cell (e.g., 100 mTorr) to convert the ions to energetic neutrals through charge transfer scattering. The resolution of NPL is generally superior to that of IBL for applications involving insulating substrates, large proximity gaps, and ultra-small features. High accuracy stepped exposures with energetic neutral particles, where magnetic or electrostatic deflection is impossible, have been obtained by clamping the mask to the wafer, setting the proximity gap with a suitable spacer, and mechanically inclining the mask/wafer stack relative to the beam. This approach is remarkably insensitive to vibration and thermal drift; nanometer scale image offsets have been obtained with +/-2 nm placement accuracy for experiments lasting over one hour. Using this nanostepping technique, linewidth versus dose curves were obtained, from which the NPL lithographic blur was determined as 4.4+/-1.4 nm (1sigma), which is 2-3 times smaller than the blur of electron beam lithography. Neutral particle lithography has the potential to form high density, periodic patterns with sub-10 nm resolution.

  5. EAST中性束注入控制系统设计%Design of control system of neutral beam inj ection on EAST

    Institute of Scientific and Technical Information of China (English)

    盛鹏; 胡纯栋; 宋士花; 刘胜

    2014-01-01

    中性束注入(NBI)是磁约束核聚变装置等离子体加热和电流驱动的重要手段。依据东方超环(EAST)NBI实验运行特点,设计了基于网络通讯的集散式控制系统。NBI控制系统采用计算机网络技术,按照控制层次分为远程监控层、服务器控制层和现场控制层,三层控制结构易于系统功能扩展与设备升级。一条束线的两个离子源可以独立运行控制,这为EAST第二条束线控制扩展奠定基础。实验表明,NBI控制系统具备了远程监控、连锁保护和数据处理功能,满足了 NBI实验运行的自动化和可视化的需求。%Neutral beam inj ection (NBI)is an important method of plasma heating and plasma current driving for magnetic confinement fusion device.A distributed control system is designed in this paper according to experimental operation characteris-tics of NBI on Experimental Advanced Superconducting Tokamak (EAST).The NBI control system based on network technolo-gy,classified according to control level,consists of remote monitoring layer,server control layer and field control layer.The three-layer control systematic architecture is easy for extending system functions and upgrading devices.Both ion sources of one NBI beam line are designed to operate independently,which lays a foundation for developing control system of the second beam line on EAST.Experimental results demonstrate that the visualization and automation of NBI experimental operations are suc-cessfully implemented by remote monitoring,interlock protection,and data processing.

  6. Counter-cryptanalysis

    NARCIS (Netherlands)

    Stevens, M.M.J.; Canetti, R.; Garay, J.A.

    2013-01-01

    We introduce \\emph{counter-cryptanalysis} as a new paradigm for strengthening weak cryptographic primitives against cryptanalytic attacks. Redesigning a weak primitive to more strongly resist cryptanalytic techniques will unavoidably break backwards compatibility. Instead, counter-cryptanalysis expl

  7. Limited Neutrality

    DEFF Research Database (Denmark)

    Nielsen, Morten Ebbe Juul

    2006-01-01

    Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."......Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."...

  8. Limited Neutrality

    DEFF Research Database (Denmark)

    Nielsen, Morten Ebbe Juul

    2006-01-01

    Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."......Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."...

  9. The beam dump tunnels

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    In these images workers are digging the tunnels that will be used to dump the counter-circulating beams. Travelling just a fraction under the speed of light, the beams at the LHC will each carry the energy of an aircraft carrier travelling at 12 knots. In order to dispose of these beams safely, a beam dump is used to extract the beam and diffuse it before it collides with a radiation shielded graphite target.

  10. FLEXIBLE GEIGER COUNTER

    Science.gov (United States)

    Richter, H.G.; Gillespie, A.S. Jr.

    1963-11-12

    A flexible Geiger counter constructed from materials composed of vinyl chloride polymerized with plasticizers or co-polymers is presented. The counter can be made either by attaching short segments of corrugated plastic sleeving together, or by starting with a length of vacuum cleaner hose composed of the above materials. The anode is maintained substantially axial Within the sleeving or hose during tube flexing by means of polystyrene spacer disks or an easily assembled polyethylene flexible cage assembly. The cathode is a wire spiraled on the outside of the counter. The sleeving or hose is fitted with glass end-pieces or any other good insulator to maintain the anode wire taut and to admit a counting gas mixture into the counter. Having the cathode wire on the outside of the counter substantially eliminates the objectional sheath effect of prior counters and permits counting rates up to 300,000 counts per minute. (AEC)

  11. Countering Internet Extremism

    Science.gov (United States)

    2009-01-01

    literally examine hundreds of books and speeches. Since the purpose of this work is examining ways to counter an extremist’s Internet use of the...provide differing perspectives on how to counter extremist Internet use . A 2008 New York Times article indirectly offers some methods. Writers Eric...or scholars have the most potential to effectively counter extremist Internet use . Such efforts could help to stifle some of the issues that

  12. A new highly segmented start counter for the CLAS detector

    Energy Technology Data Exchange (ETDEWEB)

    Sharabian, Y.G. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Battaglieri, M. [INFN Sezione di Genova, 16146 Genova (Italy); Burkert, V.D. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); DeVita, R. [INFN Sezione di Genova, 16146 Genova (Italy); Elouadrhiri, L. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Guo, L. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Kashy, D. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Kubarovsky, V. [Rensselaer Polytechnic Institute, Troy, NY 12180 and Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Mutchler, G.S. [T.W. Bonner Nuclear Laboratory, Rice University, Houton, TX 77251-1892 (United States)]. E-mail: mutchler@rice.edu; Ostrick, M. [Physikalisches Institut, Universitaet Bonn, Bonn (Germany); Ripani, M. [INFN Sezione di Genova, 16146 Genova (Italy); Rossi, P. [INFN Laboratori Nazionali di Frascati, 00044 Frascati (Italy); Rottura, A. [INFN Sezione di Genova, 16146 Genova (Italy); Pasyuk, E. [Arizona State University, Tempe, AZ, 85287-1504 (United States); Weygand, D. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States)

    2006-01-01

    The design, construction and performance of a highly segmented Start Counter are described. The Start Counter is an integral part of the trigger used in photon beam running with CLAS in Hall B at the Thomas Jefferson National Accelerator Facility (TJNAF). The Start Counter is constructed of 24 2.2-mm-thick single-ended scintillation paddles, forming a hermetic hexagon around the target region. This device measures the interaction time of the incoming photon in the target by detecting the outgoing particles. The counter provides complex trigger topologies, shows good efficiency and achieved a time resolution of 350 ps.

  13. Measurement of e{sup +}p neutral current deep inelastic scattering with a longitudinally polarised positron beam and X-ray radiation damage for silicon sensors

    Energy Technology Data Exchange (ETDEWEB)

    Januschek, Friederike

    2012-05-15

    The cross sections for Neutral Current e{sup +}p Deep Inelastic Scattering (NC DIS) with longitudinally polarised positron beams were measured at a centre-of-mass energy {radical}(s)=318 GeV using the ZEUS detector at HERA. Single-differential cross sections as a function of the virtuality of the exchanged boson, Q{sup 2}, of the inelasticity, y, and of the Bjorken scaling variable, x, and reduced cross sections (as a function of x and Q{sup 2}) were measured in the phase space region defined as Q{sup 2}>185 GeV{sup 2}, y<0.9 and y(1-x){sup 2}>0.004. The results, based on data corresponding to an integrated luminosity of 135.5 pb{sup -1}, are given for zero polarisation for the whole sample, as well as for both positive and negative values of the longitudinal polarisation of the positron beam. The measured cross sections are compared to the predictions of the Standard Model. The proton structure function xF{sub 3} is measured and the interference term xF{sup {gamma}}{sup Z}{sub 3} is extracted as a function of x at Q{sup 2}=1500 GeV{sup 2} by extrapolating the measurements done at different Q{sup 2} values. The presented measurements of the polarised e{sup +}p NC DIS cross sections, the xF{sub 3} structure function and the xF{sup {gamma}}{sup Z}{sub 3} interference term exceed the precision of previous ZEUS measurements. The uncertainties of the Parton Density Functions (PDFs) for the gluon and the u-valence quark are expected to be reduced at high-x values when the presented results are included in the PDF fits of the proton. A study is presented to further reduce PDF uncertainties for the gluon at very high x (above 10{sup -1}) through the inclusion of DIS dijet cross sections in a ZEUS-JETS-like PDF fit. An irradiation facility to study the X-ray-induced radiation damage of silicon sensors for the European XFEL was set up at HASYLAB. Nine gate-controlled diodes were irradiated with doses from 1 kGy to 1 GGy in several irradiation steps and the surface current I

  14. Anticoincidence scintillation counter

    CERN Multimedia

    1966-01-01

    This anticoincidence scintillation counter will be mounted in a hydrogen target vessel to be used in a measurement of the .beta. parameter in the .LAMBDA0. decay. The geometry of the counter optimizes light collection in the central part where a scintillation disk of variable thickness can be fitted.

  15. Proportional counter radiation camera

    Science.gov (United States)

    Borkowski, C.J.; Kopp, M.K.

    1974-01-15

    A gas-filled proportional counter camera that images photon emitting sources is described. A two-dimensional, positionsensitive proportional multiwire counter is provided as the detector. The counter consists of a high- voltage anode screen sandwiched between orthogonally disposed planar arrays of multiple parallel strung, resistively coupled cathode wires. Two terminals from each of the cathode arrays are connected to separate timing circuitry to obtain separate X and Y coordinate signal values from pulse shape measurements to define the position of an event within the counter arrays which may be recorded by various means for data display. The counter is further provided with a linear drift field which effectively enlarges the active gas volume of the counter and constrains the recoil electrons produced from ionizing radiation entering the counter to drift perpendicularly toward the planar detection arrays. A collimator is interposed between a subject to be imaged and the counter to transmit only the radiation from the subject which has a perpendicular trajectory with respect to the planar cathode arrays of the detector. (Official Gazette)

  16. Counter-propagating patterns in the BioPhotonics Workstation

    DEFF Research Database (Denmark)

    Palima, Darwin; Lindballe, T.; Kristensen, M.V.

    2010-01-01

    for stable three-dimensional manipulation of multiple particles. In this work, we analyze counter-propagating shaped-beam traps that depart from this conventional geometry. We show that projecting shaped beams with separation distances previously considered axially unstable can, in fact, enhance the trap...... by improving axial and transverse trapping stiffness. We also show interesting results of trapping and micromanipulation experiments that combine optical forces with fluidic forces. These results hint about the rich potential of using patterned counter-propagating beams for optical trapping and manipulation...

  17. A large Cerenkov counter

    CERN Multimedia

    1981-01-01

    The photo shows the vertex Cerenkov counter C0 back side (with 12 mirrors) of the NA9 experiment. On foreground are members of the team (CERN and Wuppertal Uni), Salvo .., Manfred Poetsch, ..., Jocelyn Thadome, Helmut Braun, Heiner Brueck.

  18. Counter-cryptanalysis

    NARCIS (Netherlands)

    M.M.J. Stevens (Marc); R. Canetti; J.A. Garay

    2013-01-01

    textabstractWe introduce \\emph{counter-cryptanalysis} as a new paradigm for strengthening weak cryptographic primitives against cryptanalytic attacks. Redesigning a weak primitive to more strongly resist cryptanalytic techniques will unavoidably break backwards compatibility. Instead,

  19. Comparison of a designed virtual counter with a real counter

    Science.gov (United States)

    Tektas, G.; Celiktas, C.

    2017-02-01

    A counter is a device which counts the incident pulses within a fixed time. In this work, a virtual counter was designed by developing a code by LabVIEW software. Generator signals were sent to the virtual counter via a National Instruments multifunction data acquisition device. Analog and PFI (Programmable Function Interface) inputs of the device was used for the process. A real counter was also used for comparison. Counts acquired from both counters in different time intervals were compared with each other. It was concluded from the obtained results that the developed virtual counter could be used as a real counter.

  20. Full simulation of the Sudbury Neutrino Observatory proportional counters

    Energy Technology Data Exchange (ETDEWEB)

    Beltran, B; Habib, S; Hallin, A L [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2R3 (Canada); Bichsel, H; Cox, G A; Formaggio, J A; McGee, S; Miller, M L; Oblath, N S [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 (United States); Cai, B; Kraus, C; Leslie, H R; Martin, R [Department of Physics, Queen' s University, Kingston, Ontario K7L 3N6 (Canada); Deng, H [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104-6396 (United States); Detwiler, J; Loach, J C [Institute for Nuclear and Particle Astrophysics and Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Hime, A [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Huang, M [Department of Physics, University of Texas at Austin, Austin, TX 78712-0264 (United States); Monreal, B; Monroe, J, E-mail: nsoblath@mit.edu [Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2011-07-15

    The third phase of the Sudbury Neutrino Observatory (SNO) experiment added an array of {sup 3}He proportional counters to the detector. The purpose of this neutral-current detection (NCD) array was to observe neutrons resulting from neutral-current solar-neutrino-deuteron interactions. We have developed a detailed simulation of current pulses from NCD array proportional counters, from the primary neutron capture on {sup 3}He through NCD array signal-processing electronics. This NCD array MC simulation was used to model the alpha-decay background in SNO's third-phase {sup 8}B solar-neutrino measurement.

  1. Full simulation of the Sudbury Neutrino Observatory proportional counters

    CERN Document Server

    Beltran, B; Cai, B.; Cox, G.A.; Deng, H.; Detwiler, J.; Formaggio, J.A.; Habib, S.; Hallin, A.L.; Hime, A.; Huang, M.; Kraus, C.; Leslie, H.R.; Loach, J.C.; Martin, R.; McGee, S.; Miller, M.L.; Monreal, B.; Monroe, J.; Oblath, N.S.; Peeters, S.J.M.; Poon, A.W.P.; Prior, G.; Rielage, K.; Robertson, R.G.H.; Smith, M.W.E.; Stonehill, L.C.; Tolich, N.; Van Wechel, T.; Wan Chan Tseung, H.; Wendland, J.; Wilkerson, J.F.; Wright, A.

    2011-01-01

    The third phase of the Sudbury Neutrino Observatory (SNO) experiment added an array of 3He proportional counters to the detector. The purpose of this Neutral Current Detection (NCD) array was to observe neutrons resulting from neutral-current solar neutrino-deuteron interactions. We have developed a detailed simulation of the current pulses from the NCD array proportional counters, from the primary neutron capture on 3He through the NCD array signal-processing electronics. This NCD array Monte Carlo simulation was used to model the alpha-decay background in SNO's third-phase 8B solar-neutrino measurement.

  2. Organic neutralization agents for neutralization-reionization mass spectrometry.

    Science.gov (United States)

    Zhang, M Y; McLafferty, F W

    1992-02-01

    Porter has shown that excited neutrals of specified internal energies can be prepared by neutralization of an ion beam with metal vapors of low ionization potential (IP). For specific problems in neutralization-reionization mass spectrometry, a metal with the desired IP value may not be available, or it may present experimental problems such as a high vaporization temperature, instrument contamination, or detector instability. The use of organic neutralization agents such as tetra-p-anisylethylene (IP = 6.0 eV) can minimize these problems (although cross sections for neutralization with these are a factor of 5 lower than those with metals), and can provide a much wider range of IP values. Their utility is demonstrated in the neutralization of C4H4 (+•) and CH8 (+•) ions to produce C4H4 and C4H8 of selected internal energies. However, for CH4 (+•) neutralization, the CH4 neutrals formed have a much lower internal energy than predicted, indicating that electron transfer from the neutralization agent predominantly produces its ions in excited states.

  3. Measuring Cherenkov Backgrounds from Proportional Counters in SNO

    Science.gov (United States)

    Seibert, Stanley

    2006-04-01

    In the current phase of operation of the Sudbury Neutrino Observatory, He-3 proportional counters have been deployed in the center of the detector to measure neutron production from neutral-current interactions between neutrinos and deuterons in the heavy water. Radioactive decays of Bi-214 and Tl-208 in the counters produce gammas of sufficient energy to photodisintegrate deuterons, which become a background to the neutral current measurement. We have measured the background rate in-situ using Cherenkov light detected with SNO's 9456 inward-looking photomultiplier tubes. A maximum likelihood method is used to separate backgrounds in the heavy water from backgrounds in the proportional counters based upon the spatial distribution of low energy Cherenkov event vertices. Uncertainties on the backgrounds have been estimated using calibration data taken with both a distributed Na-24 source, and a contained Th source deployed at various points in the detector.

  4. Geiger Counter Technique

    Science.gov (United States)

    1942-01-01

    is a Genco HIyvac and is backed by a single stage oil diffusion punp. The mercury well is emnloyed as a pump and mixing chamber, providing a means of...system, after first being puaped down, is filled to ovar-priees-e with Argan . re counter is then pullet off the ribber tubing a few dorps of ether are

  5. Measurement of single pi0 production in neutral current neutrino interactions with water by a 1.3 GeV wide band muon neutrino beam

    CERN Document Server

    Nakayama, S; Aoki, S; Ashie, Y; Bhang, H; Boyd, S; Casper, D; Choi, J H; Fukuda, S; Fukuda, Y; Gran, R; Hara, T; Hasegawa, M; Hasegawa, T; Hayashi, K; Hayato, Y; Hill, J; Ichikawa, A K; Ikeda, A; Inagaki, T; Ishida, T; Ishii, T; Ishitsuka, M; Itow, Y; Iwashita, T; Jang, H I; Jang, J S; Jeon, E J; Joo, K K; Jung, C K; Kajita, T; Kameda, J; Kaneyuki, K; Kato, I; Kearns, E; Kibayashi, A; Kielczewska, D; Kim, B J; Kim, C O; Kim, J Y; Kim, S B; Kobayashi, K; Kobayashi, T; Koshio, Y; Kropp, W R; Learned, J G; Lim, S H; Lim, I T; Maesaka, H; Maruyama, T; Matsuno, S; Mauger, C; McGrew, C; Minamino, A; Mine, S; Miura, M; Miyano, K; Morita, T; Moriyama, S; Nakahata, M; Nakamura, K; Nakano, I; Nakata, F; Nakaya, T; Nakayama, S; Namba, T; Nambu, R; Nishikawa, K; Nishiyama, S; Noda, S; Obayashi, Y; Okada, A; Oyama, Y; Pac, M Y; Park, H; Saji, C; Sakuda, M; Sarrat, A; Sasaki, T; Sasao, N; Scholberg, K; Sekiguchi, M; Sharkey, E; Shiozawa, M; Shiraishi, K K; Smy, M B; Sobel, H W; Stone, J L; Suga, Y; Sulak, L R; Suzuki, A; Suzuki, Y; Takeuchi, Y; Tamura, N; Tanaka, M; Totsuka, Y; Ueda, S; Vagins, M R; Walter, C W; Wang, W; Wilkes, R J; Yamada, S; Yamamoto, S; Yanagisawa, C; Yokoyama, H; Yoo, J; Yoshida, M; Zalipska, J

    2005-01-01

    Neutral current single pi0 production induced by neutrinos with a mean energy of 1.3 GeV is measured at a 1000 ton water Cherenkov detector as a near detector of the K2K long baseline neutrino experiment. The cross section for this process relative to the total charged current cross section is measured to be 0.064 +- 0.001 (stat.) +- 0.007 (sys.). The momentum distribution of produced pi0s is measured and is found to be in good agreement with an expectation from the present knowledge of the neutrino cross sections.

  6. Characteristics of confinement and fusion reactivity in JT-60U high-{beta}{rho} and TFTR supershot regimes with deuterium neutral beam injection

    Energy Technology Data Exchange (ETDEWEB)

    Park, H.K.; Bell, M.G.; Yamada, M.

    1995-03-01

    The high performance regimes achieved in JT-60U and TFTR have produced peak DD fusion neutron rates up to 5.6 {times} 10{sup 16}/s for similar heating beam powers, in spite of considerable differences in machine operation and plasma configuration. A common scaling for the DD fusion neutron rate (S{sub DD} {proportional_to} P{sub abs}{sup 2.0} H{sub ne} V{sub p}{sup {minus}0.9}) is obtained, where P{sub abs} and H{sub ne} are the absorbed beam power and beam fueling peaking factor, respectively, and V{sub p} is the plasma volume. The maximum stored energy obtained in each machine has been up to 5.4 MJ in TFTR and 8.7 MJ in JT-60U. Further improvements in the fusion neutron rate and the stored energy are limited by the {beta}-limit in Troyon range, {beta}{sub N} {approximately} 2.0--2.5. A common scaling for the stored energy (W{sub tot} {proportional_to} P{sub abs}V{sub p}H{sub ne}{sup 0.2}) is also proposed.

  7. Countering rumors about contraceptives.

    Science.gov (United States)

    Del Rosario, M L

    1976-01-01

    Rumors are among the serious problems of the National Population Program today. The principles related to the origin of rumors, who starts rumors pertaining to family planning, and how they spread are outlined. The basic approach in countering rumors for the pill and IUD is diagrammed so that each potential rumor is countered by a medical or nonmedical/technical explanation. Strategies used by information-education-communication programs to prevent rumors such as the small group discussion, selection and training of motivators, and use of mass media are discussed. Rumors about family planning are counteracted not with the use of elaborate techniques but with clear and fairly simple reassurances supported by medical evidence and case histories.

  8. Impurity Dynamics under Neutral Beam Injection at TJ-II (simulation); Dinamica de Impurezas durante la Inyeccion de Haces Neutros en el TJ-II (simulacion)

    Energy Technology Data Exchange (ETDEWEB)

    Guasp, J.; Fuentes, C.; Liniers, M.

    2001-07-01

    In this study the simulations of plasma transport under NBI for TJ-II, previously performed, are extended. Since than a considerable number of important modifications have been introduced in the model: change of magnetic configuration, use of experimental initial profiles, expansion of the Data base from NBI calculations and, mainly, a detailed handling of impurities with inclusion of sputtering effects. Moreover there is now a particular emphasis on the analysis of the conditions for discharge collapse and on the possible effects of single beam injection. This analysis of impurity behaviour with sputtering shows that in the expected usual cases there is no radioactive collapse and that if the recycling coefficients remain lower the unity it is always possible to find a strategy for external gas puffing leading to a stationary state, with densities below the limit and efficient NBI absorption (>50%). The radioactive collapse can appear either at high densities (central value higher than 1.4x10''20 m''3), excessive influx of impurities (i. e. with sputtering rates higher than twice the expected values) o for insufficient injected beam power (less than 45 kW). The present study analyses only the 100{sub 4}4{sub 6}4 configuration of TJ-II, but future works will start a systematic scan of configuration using this same model. (Author) 12 Refs.

  9. Spectroscopy of neutral radium

    Energy Technology Data Exchange (ETDEWEB)

    Mol, Aran; De, Subhadeep; Jungmann, Klaus; Wilschut, Hans; Willmann, Lorenz [KVI, University of Groningen, Groningen (Netherlands)

    2008-07-01

    The heavy alkaline earth atoms radium is uniquely sensitive towards parity and time reversal symmetry violations due to a large enhancement of an intrinsic permanent electric dipole moment of the nucleous or the electron. Furthermore, radium is sensitive to atomic parity violation and the nuclear anapole moment. To prepare such experiments spectroscopy of relevant atomic states need to be done. At a later stage we will build a neutral atom trap for radium. We have built an atomic beam of the short lived isotope {sup 225}Ra with a flux of several 10{sup 4} atoms/sec. We are preparing the laser spectroscopy using this beam setup. In the preparation for efficient laser cooling and trapping we have successfully trapped barium, which is similar in it's requirements for laser cooling. The techniques which we have developed with barium can be used to trap rare radium isotopes. We report on the progress of the experiments.

  10. Measurement of angular divergence and ion species ratios of an rf-driven multicusp ion source for diagnostic neutral beam by Doppler shift spectroscopy

    Science.gov (United States)

    Yoo, S. J.; Yang, H. L.; Hwang, S. M.

    2000-03-01

    The ion species ratios as well as the angular divergences are measured by using a Doppler shift spectroscopy of Hα spectral lines, which originate from several different ions, such as H2+ and H3+ as well as H+, and are spectrally well resolvable from each other on the measured spectral window of detection system. The angular divergences of the ion beam components are determined from the linewidths of the measured emission lines, and the ratio of mixed species is deduced from the intensity ratio of each peak. The ion species ratios measured by the Doppler shift spectroscopy are cross checked by a mass analyzing magnet. The measurements are performed varying the input rf power and the operating source pressure.

  11. Electromagnetic shower counter

    CERN Multimedia

    1974-01-01

    The octogonal block of lead glass is observed by eight photomultiplier tubes. Four or five such counters, arranged in succession, are used on each arm of the bispectrometer in order to detect heavy particles of the same family as those recently observed at Brookhaven and SLAC. They provide a means of identifying electrons. The arrangement of eight lateral photomultiplier tubes offers an efficient means of collecting the photons produced in the showers and determining, with a high resolution, the energy of the incident electrons. The total width at half-height is less than 6.9% for electrons having an energy of 1 GeV.

  12. Quantum counter automata

    CERN Document Server

    Say, A C Cem

    2011-01-01

    The question of whether quantum real-time one-counter automata (rtQ1CAs) can outperform their probabilistic counterparts has been open for more than a decade. We provide an affirmative answer to this question, by demonstrating a non-context-free language that can be recognized with perfect soundness by a rtQ1CA. This is the first demonstration of the superiority of a quantum model to the corresponding classical one in the real-time case with an error bound less than 1. We also introduce a generalization of the rtQ1CA, the quantum one-way one-counter automaton (1Q1CA), and show that they too are superior to the corresponding family of probabilistic machines. For this purpose, we provide general definitions of these models that reflect the modern approach to the definition of quantum finite automata, and point out some problems with previous results. We identify several remaining open problems.

  13. Counter-Rotating Accretion Discs

    OpenAIRE

    Dyda, Sergei; Lovelace, Richard V. E.; Ustyugova, Galina V.; Romanova, Marina M.; Koldoba, Alexander V.

    2014-01-01

    Counter-rotating discs can arise from the accretion of a counter-rotating gas cloud onto the surface of an existing co-rotating disc or from the counter-rotating gas moving radially inward to the outer edge of an existing disc. At the interface, the two components mix to produce gas or plasma with zero net angular momentum which tends to free-fall towards the disc center. We discuss high-resolution axisymmetric hydrodynamic simulations of a viscous counter-rotating disc for cases where the tw...

  14. Space and power efficient hybrid counters array

    Science.gov (United States)

    Gara, Alan G.; Salapura, Valentina

    2009-05-12

    A hybrid counter array device for counting events. The hybrid counter array includes a first counter portion comprising N counter devices, each counter device for receiving signals representing occurrences of events from an event source and providing a first count value corresponding to a lower order bits of the hybrid counter array. The hybrid counter array includes a second counter portion comprising a memory array device having N addressable memory locations in correspondence with the N counter devices, each addressable memory location for storing a second count value representing higher order bits of the hybrid counter array. A control device monitors each of the N counter devices of the first counter portion and initiates updating a value of a corresponding second count value stored at the corresponding addressable memory location in the second counter portion. Thus, a combination of the first and second count values provide an instantaneous measure of number of events received.

  15. The microstrip proportional counter

    Science.gov (United States)

    Ramsey, B. D.

    1992-01-01

    Microstrip detectors in which the usual discrete anode and cathode wires are replaced by conducting strips on an insulating or partially insulating substrate are fabricated using integrated circuit-type photolithographic techniques and hence offer very high spatial accuracy and uniformity, together with the capability of producing extremely fine electrode structures. Microstrip proportional counters have now been variously reported having an energy resolution of better than 11 percent FWHM at 5.9 keV. They have been fabricated with anode bars down to 2 microns and on a variety of substrate materials including thin films which can be molded to different shapes. This review will examine the development of the microstrip detector with emphasis on the qualities which make this detector particularly interesting for use in astronomy.

  16. Counter-Learning under Oppression

    Science.gov (United States)

    Kucukaydin, Ilhan

    2010-01-01

    This qualitative study utilized the method of narrative analysis to explore the counter-learning process of an oppressed Kurdish woman from Turkey. Critical constructivism was utilized to analyze counter-learning; Frankfurt School-based Marcusian critical theory was used to analyze the sociopolitical context and its impact on the oppressed. Key…

  17. 30-ps time resolution with segmented scintillation counter for MEG II

    Science.gov (United States)

    Uchiyama, Y.; Boca, G.; Cattaneo, P. W.; De Gerone, M.; Gatti, F.; Nakao, M.; Nishimura, M.; Ootani, W.; Pizzigoni, G.; Rossella, M.; Simonetta, M.; Yoshida, K.

    2017-02-01

    A new timing detector has been developed to measure ∼50 MeV/c positrons with a time resolution of σt ≃ 30 ps in the MEG II experiment. The detector are segmented into 512 scintillation counters, each of which consists of 120 ×(40 or 50) × 5mm3 size BC-422 and two arrays of six AdvanSiD silicon photomultipliers. The single-counter resolutions are measured to be 70-80 ps. The counter layout is optimized to get the maximum number of hit counters (on average 9 for signal positrons). This multiple-counters measurement leads to a significant improvement in the time resolution down to 30 ps. Using the first one-fourth (128) counters, a pilot run was carried out using the MEG II beam of 7 ×107μ+ / s and the basic functionality was tested.

  18. Single neutral pion production by charged-current $\\bar{\

    CERN Document Server

    Aliaga, L; Bercellie, A; Bodek, A; Bravar, A; Brooks, W K; Butkevich, A; Caicedo, D A Martinez; Carneiro, M F; Christy, M E; Chvojka, J; da Motta, H; Devan, J; Dytman, S A; Díaz, G A; Eberly, B; Felix, J; Fields, L; Fine, R; Gago, A M; Gallagher, H; Gran, R; Harris, D A; Higuera, A; Hurtado, K; Kordosky, M; Le, T; Maher, E; Manly, S; Mann, W A; Marshall, C M; McFarland, K S; McGivern, C L; McGowan, A M; Miller, J; Morfín, J G; Mousseau, J; Nelson, J K; Norrick, A; Osta, J; Palomino, J L; Paolone, V; Park, J; Patrick, C E; Perdue, G N; Rakotondravohitra, L; Ramirez, M A; Ransome, R D; Ray, H; Ren, L; Rodrigues, P A; Ruterbories, D; Schellman, H; Schmitz, D W; Sobczyk, J T; Salinas, C J Solano; Tagg, N; Tice, B G; Valencia, E; Walton, T; Wolcott, J; Yepes-Ramirez, H; Zavala, G; Zhang, D; Ziemer, B P

    2015-01-01

    Single neutral pion production via muon antineutrino charged-current interactions in plastic scintillator (CH) is studied using the \\minerva detector exposed to the NuMI low-energy, wideband antineutrino beam at Fermilab. Measurement of this process constrains models of neutral pion production in nuclei, which is important because the neutral-current analog is a background for $\\bar{\

  19. Fast scintillation counters for the D0 muon system upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Baldin, B. [Fermi National Accelerator Lab., Batavia, IL (United States); Abramov, V.; Babintsev, V. [and others

    1999-08-01

    The design and main parameters of the completely redesigned D0 Forward Angle Muon System (FAMUS: 1.0 < {vert_bar}{eta}{vert_bar} < 2.0) for the next high luminosity Tevatron Collider run are reported. Results of the studies of trigger scintillation counters based on fast scintillator Bicron 404A and WLS bars SOFZ-105 are presented. The authors report about results of test beam studies of prototype counters including minimum ionizing particles detection efficiency, time resolution and amplitude response. Radiation ageing of scintillating materials for the doses up to 1 Mrad, phototubes magnetic shielding in the fields of up to 700 G and ageing of phototubes are presented. All tests show robustness of scintillation counters as triggering detector of the new muon system for a long period.

  20. Counter-driver shock tube

    Science.gov (United States)

    Tamba, T.; Nguyen, T. M.; Takeya, K.; Harasaki, T.; Iwakawa, A.; Sasoh, A.

    2015-11-01

    A "counter-driver" shock tube was developed. In this device, two counter drivers are actuated with an appropriate delay time to generate the interaction between a shock wave and a flow in the opposite direction which is induced by another shock wave. The conditions for the counter drivers can be set independently. Each driver is activated by a separate electrically controlled diaphragm rupture device, in which a pneumatic piston drives a rupture needle with a temporal jitter of better than 1.1 ms. Operation demonstrations were conducted to evaluate the practical performance.

  1. Two Photon Absorption Laser Induced Fluorescence for Neutral Hydrogen Profile Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Scime, Earl E. [West Virginia Univ., Morgantown, WV (United States)

    2016-09-23

    The magnitude and spatial dependence of neutral density in magnetic confinement fusion experiments is a key physical parameter, particularly in the plasma edge. Modeling codes require precise measurements of the neutral density to calculate charge-exchange power losses and drag forces on rotating plasmas. However, direct measurements of the neutral density are problematic. In this work, we proposed to construct a laser-based diagnostic capable of providing spatially resolved measurements of the neutral density in the edge of plasma in the DIII-D tokamak. The diagnostic concept is based on two-photon absorption laser induced fluorescence (TALIF). By injecting two beams of 205 nm light (co or counter propagating), ground state hydrogen (or deuterium or tritium) can be excited from the n = 1 level to the n = 3 level at the location where the two beams intersect. Individually, the beams experience no absorption, and therefore have no difficulty penetrating even dense plasmas. After excitation, a fraction of the hydrogen atoms decay from the n = 3 level to the n = 2 level and emit photons at 656 nm (the Hα line). Calculations based on the results of previous TALIF experiments in magnetic fusion devices indicated that a laser pulse energy of approximately 3 mJ delivered in 5 ns would provide sufficient signal-to-noise for detection of the fluorescence. In collaboration with the DIII-D engineering staff and experts in plasma edge diagnostics for DIII-D from Oak Ridge National Laboratory (ORNL), WVU researchers designed a TALIF system capable of providing spatially resolved measurements of neutral deuterium densities in the DIII-D edge plasma. The laser systems were specified, purchased, and assembled at WVU. The TALIF system was tested on a low-power hydrogen discharge at WVU and the plan was to move the instrument to DIII-D for installation in collaboration with ORNL researchers. After budget cuts at DIII-D, the DIII-D facility declined to support

  2. Beam distribution reconstruction simulation for electron beam probe

    CERN Document Server

    Feng, Yongchun; Li, Peng; Kang, Xincai; Yin, Yan; Liu, Tong; You, Yaoyao; Chen, Yucong; Zhao, Tiecheng; Xu, Zhiguo; Wang, Yanyu; Yuan, Youjin

    2016-01-01

    Electron beam probe (EBP) is a new principle detector, which makes use of a low-intensity and low-energy electron beam to measure the transverse profile, bunch shape, beam neutralization and beam wake field of an intense beam with small dimensions. While can be applied to many aspects, we limit our analysis to beam distribution reconstruction. This kind of detector is almost non-interceptive for all of the beam and does not disturb the machine environment. In this paper, we present the theoretical aspects behind this technique for beam distribution measurement and some simulation results of the detector involved. First, a method to obtain parallel electron beam is introduced and a simulation code is developed. And then, EBP as a profile monitor for dense beam is simulated using fast scan method under various target beam profile, such as KV distribution, waterbag distribution, parabolic distribution, Gaussian distribution and halo distribution. Profile reconstruction from the deflected electron beam trajectory...

  3. A new technique to measure the neutralizer cell gas line density applied to a DIII-D neutral beamline

    Energy Technology Data Exchange (ETDEWEB)

    Kessler, D.N.; Hong, R.M.; Riggs, S.P.

    1995-10-01

    The DIII-D tokamak employs eight ion sources for plasma heating. In order to obtain the maximum neutralization of energetic ions (providing maximum neutral beam power) and reduce the heat load on beamline internal components caused by residual energetic ions, sufficient neutral gas must be injected into the beamline neutralizer cell. The neutral gas flow rate must be optimized, however, since excessive gas will increase power losses due to neutral beam scattering and reionization. It is important, therefore, to be able to determine the neutralizer cell gas line density. A new technique which uses the ion source suppressor grid current to obtain the neutralizer cell gas line density has been developed. The technique uses the fact that slow ions produced by beam-gas interactions in the neutralizer cell during beam extraction are attracted to the negative potential applied to the suppressor grid, inducing current flow in the grid. By removing the dependence on beam energy and beam current a normalized suppressor grid current function can be formed which is dependent only on the gas line density. With this technique it is possible to infer the gas line density on a shot by shot basis.

  4. 基于ANSYS的中性束注入器主真空室结构力学分析%Structural mechanics analysis on vacuum chamber of neutral beam injector based on ANSYS

    Institute of Scientific and Technical Information of China (English)

    曹占龙; 刘智民; 谢远来; 马功哲; 胡纯栋

    2012-01-01

    A finite element model for main vacuum chamber of EAST Neutral Beam Injector prototype was built with ANSYS software.The stress of the vacuum chamber was analyzedThe vacuum chamber was assembled by three sections,which should be analyzed respectively for structural statics with sections lying on ground and being laid on rails after connecting to obtain structural stress distribution and deformation under corresponding operating conditions Analysis showed that the maximum Von-Mises equivalent stress of the vacuum chamber is less than material yield strength in two operating conditions.The structure of vacuum chamber is safe and stable.The calculation result provides the reference for the optimization and the selection of material.%利用ANSYS软件建立了EAST中性束注入器样机主真空室的有限元模型,分析了主真空室的受力情况;主真空室由三段组装而成,依据实际的材料和受力情况,分别对三段放置于地面以及整体连接放置在导轨上两种工作状况下进行结构静力学分析,得到了相应工作状况下的结构应力分布和变形情况.分析表明主真空室在两种工作状况下最大Von-Mises等效应力值小于材料屈服强度,主真空室结构是安全和稳定的,分析结果给主真空室下一步的优化设计和结构选材提供了依据.

  5. Over-the-Counter Medicines

    Science.gov (United States)

    Over-the-counter (OTC) medicines are drugs you can buy without a prescription. Some OTC medicines relieve aches, pains ... Others help manage recurring problems, like migraines. In the United States, the Food and Drug Administration decides ...

  6. What is Neutrality?

    NARCIS (Netherlands)

    Pierik, R.; van der Burg, W.

    2014-01-01

    This paper reinvestigates the question of liberal neutrality. We contend that current liberal discussions have been dominated - if not hijacked - by one particular interpretation of what neutrality could imply, namely, exclusive neutrality, that aims to exclude religious and cultural expressions

  7. Performance of Scintillator Counters with Silicon Photomultiplier Readout

    CERN Document Server

    Artikov, A; Chokheli, D; Davydov, Yu I; Dukes, E C; Ehrlich, R; Francis, K; Frank, M J; Glagolev, V; Hansen, S; Hocker, A; Oksuzian, Y; Rubinov, P; Song, E; Uzunyan, S; Wu, Y

    2015-01-01

    The performance of scintillator counters with embedded wavelength-shifting fibers has been measured in the Fermilab Meson Test Beam Facility using 120 GeV protons. The counters were extruded with a titanium dioxide surface coating and two channels for fibers at the Fermilab NICADD facility. Each fiber end is read out by a 2*2 mm^2 silicon photomultiplier. The signals were amplified and digitized by a custom-made front-end electronics board. Combinations of 5*2 cm^2 and 6*2 cm^2 extrusion profiles with 1.4 and 1.8 mm diameter fibers were tested. The design is intended for the cosmic-ray veto detector for the Mu2e experiment at Fermilab. The light yield as a function of the transverse and longitudinal position of the beam will be given.

  8. Microstrip proportional counter development at MSFC

    Science.gov (United States)

    Fulton, M. A.; Kolodziejczak, J. J.; Ramsey, B. D.

    1992-01-01

    Microstrip detectors are an exciting new development in proportional counter design fabricated using integrated circuit-type photolithography techniques; they therefore offer very high spatial accuracy and uniformity. A development program is underway at NASA-Marshall to produce large-area microstrips for use in an X-ray detector balloon flight program and to investigate the general performance limits of these new devices. Microstrips tested so far have been fabricated both in-house using standard photolithographic techniques and by an outside contractor using electron beam technology. Various substrate materials have been tested along with different electrode configurations. The distributions of pickup on subdivided cathodes on both top and bottom surfaces of the microstrips are also being investigated for use as two-dimensional imaging detectors. Data from these tests in the development of a large-area device will be presented.

  9. Large scale test of wedge shaped micro strip gas counters

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, M.; Atz, S.; Aulchenko, V.; Bachmann, S.; Baiboussinov, B.; Barthe, S.; Beaumont, W.; Beckers, T.; Beissel, F.; Benhammou, Y.; Bergdolt, A.M.; Bernier, K.; Bluem, P.; Bondar, A.; Bouhali, O.; Boulogne, I.; Bozzo, M.; Brom, J.M.; Camps, C.; Chorowicz, V.; Coffin, J.; Commichau, V.; Contardo, D.; Croix, J.; Troy, J. de; Drouhin, F.; Eberle, H.; Fluegge, G.; Fontaine, J.-C.; Geist, W.; Goerlach, U.; Gundlfinger, K.; Hangarter, K.; Haroutunian, R.; Helleboid, J.M.; Henkes, Th.; Hoffer, M.; Hoffman, C.; Huss, D.; Ischebeck, R.; Jeanneau, F.; Juillot, P.; Junghans, S.; Kapp, M.R.; Kaercher, K.; Knoblauch, D.; Kraeber, M.; Krauth, M.; Kremp, J.; Lounis, A.; Luebelsmeyer, K.; Maazouzi, C.; Macke, D.; Metri, R.; Mirabito, L.; Mueller, Th.; Nagaslaev, V.; Neuberger, D.; Nowack, A.; Pallares, A.; Pandoulas, D.; Petertill, M.; Pooth, O.; Racca, C.; Ripp, I.; Ruoff, E.; Sauer, A.; Schmitz, P.; Schulte, R.; Schultz von Dratzig, A.; Schunk, J.P.; Schuster, G.; Schwaller, B.; Shektman, L.; Siedling, R.; Sigward, M.H.; Simonis, H.J.; Smadja, G.; Stefanescu, J.; Szczesny, H.; Tatarinov, A.; Thuemmel, W.H.; Tissot, S.; Titov, V.; Todorov, T.; Tonutti, M.; Udo, F.; Velde, C. Vander. E-mail: vandervelde@hep.iihe.ac.be; Doninck, W. van; Dyck, Ch. van; Vanlaer, P.; Lancker, L. van; Verdini, P.G.; Weseler, S.; Wittmer, B.; Wortmann, R.; Zghiche, A.; Zhukov, V

    1999-11-01

    In order to check the system aspects of the forward-backward MSGC tracker designed for the future CMS experiment at LHC, 38 trapezoidal MSGC counters assembled in six multi-substrates detector modules were built and exposed to a muon beam at the CERN SPS. Results on the gain uniformity along the wedge-shaped strip pattern and across the detector modules are shown together with measurements of the detection efficiency and the spatial resolution.

  10. Large scale test of wedge shaped micro strip gas counters

    CERN Document Server

    Ackermann, M; Aulchenko, V M; Bachmann, S; Baibusinov, B O; Barthe, S; Beaumont, W; Beckers, T; Beissel, F; Benhammou, Ya; Bergdolt, A M; Bernier, K; Blüm, H P; Bondar, A E; Bouhali, O; Boulogne, I; Bozzo, M; Brom, J M; Camps, C; Chorowicz, V; Coffin, J P; Commichau, V; Contardo, D; Croix, J; De Troy, J G; Drouhin, F; Eberle, H; Flügge, G; Fontaine, J C; Geist, Walter M; Goerlach, U; Gundlfinger, K; Hangarter, K; Haroutunian, R; Helleboid, J M; Henkes, T; Hoffer, M; Hoffmann, C; Huss, D; Ischebeck, R; Jeanneau, F; Juillot, P; Junghans, S; Kapp, M R; Kärcher, K; Knoblauch, D; Kräber, M H; Krauth, M; Kremp, J; Lounis, A; Lübelsmeyer, K; Maazouzi, C; Macke, D; Metri, R; Mirabito, L; Müller, T; Nagaslaev, V; Neuberger, D; Nowak, A; Pallarès, A; Pandoulas, D; Petertill, M; Pooth, O; Racca, C; Ripp, I; Ruoff, E; Sauer, A; Schmitz, P; Schulte, R; Schultz von Dratzig, A; Schunk, J P; Schuster, G; Schwaller, B; Shekhtman, L I; Siedling, R; Sigward, M H; Simonis, H J; Smadja, G; Stefanescu, J; Szczesny, H; Tatarinov, A A; Thümmel, W H; Tissot, S; Titov, V; Todorov, T; Tonutti, M; Udo, Fred; Van der Velde, C; Van Doninck, W K; Van Dyck, C; Vanlaer, P; Van Lancker, L; Verdini, P G; Weseler, S; Wittmer, B; Wortmann, R; Zghiche, A; Zhukov, V

    1999-01-01

    In order to check the system aspects of the forward-backward MSGC tracker designed for the future CMS experiment at LHC, 38 trapezoidal MSGC counters assembled in six multi-substrates detector modules were built and exposed to a muon beam at the CERN SPS. Results on the gain uniformity along the wedge-shaped strip pattern and across the detector modules are shown together with measurements of the detection efficiency and the spatial resolution. (8 refs).

  11. The consequences of Israel's counter terrorism policy

    OpenAIRE

    Jansen, Pia Therese

    2008-01-01

    The main focus of this thesis is to examine Israel's counter terrorism methods and their consequences and to debate the effectiveness of Israel's counter terrorism policy. By stimulating a debate on these issues it is possible to identify a more effective counter terrorism policy. In order to examine Israel's counter terrorism methods, their consequences and effectiveness, it is necessary to first explore the overall concepts of terrorism and counter terrorism. Then, because...

  12. Turbulent mixing condensation nucleus counter

    Science.gov (United States)

    Mavliev, Rashid

    The construction and operating principles of the Turbulent Mixing Condensation Nucleus Counter (TM CNC) are described. Estimations based on the semiempirical theory of turbulent jets and the classical theory of nucleation and growth show the possibility of detecting particles as small as 2.5 nm without the interference of homogeneous nucleation. This conclusion was confirmed experimentally during the International Workshop on Intercomparison of Condensation Nuclei and Aerosol Particle Counters (Vienna, Austria). Number concentration, measured by the Turbulent Mixing CNC and other participating instruments, is found to be essentially equal.

  13. Countering 21st Century Threats

    DEFF Research Database (Denmark)

    Scharling Pedersen, Peter; Pillai, Chad M.; Hun, Lee Jae

    2015-01-01

    ), Counter-Terrorism (CT), and Security and Stability Operations (SSO). • Establishing a construct that allows a strategic Whole-of-Government capacity for operations coordinated by joint interagency task forces. • Continue to developing the Global SOF network. • Increased intelligence sharing in areas...... to be addressed in order to successfully conduct IW. As result of researching the issues associated with developing a JIIM approach to IW, the paper makes the following recommendations: • Establishing universally accepted concepts and doctrines for IW, UW, Foreign Internal Defense (FID), Counter Insurgency (COIN...

  14. Neutral Operator and Neutral Differential Equation

    Directory of Open Access Journals (Sweden)

    Jingli Ren

    2011-01-01

    Full Text Available In this paper, we discuss the properties of the neutral operator (Ax(t=x(t−cx(t−δ(t, and by applying coincidence degree theory and fixed point index theory, we obtain sufficient conditions for the existence, multiplicity, and nonexistence of (positive periodic solutions to two kinds of second-order differential equations with the prescribed neutral operator.

  15. Gas-multiplication factor of a proportional counter operated at low temperature described with the Diethorn, Rose-Korff and townsend expressions

    Energy Technology Data Exchange (ETDEWEB)

    Fukumura, Kazuko; Nakanishi, Akio; Kobayashi, Takayuki [Shiga Univ. of Medical Science, Otsu (Japan)

    1996-07-01

    In the present work, the gas-multiplication factor is expressed with the Rose-Korff and Townsend methods as well as with the Diethorn method. A proportional counter with helium or neon works only at low temperature. This is discussed in terms of the number of electrons emitted when an ion is neutralized at the cathode of the counter. (J.P.N.)

  16. The LIPSS search for light neutral bosons

    Energy Technology Data Exchange (ETDEWEB)

    Andrei Afanasev; Oliver K. Baker; Kevin Beard; George Biallas; James Boyce; Minarni Minarni; Roopchan Ramdon; Michelle D. Shinn; Penny Slocum

    2009-07-01

    An overview is presented of the LIPSS experimental search for very light neutral bosons using laser light from Jefferson Lab's Free Electron Laser. This facility provides very high power beams of photons over a large optical range, particularly at infrared wavelengths. Data has been collected in several experimental runs during the course of the past three years, most recently in the Fall of 2009.

  17. Counter-Rotating Accretion Discs

    CERN Document Server

    Dyda, Sergei; Ustyugova, Galina V; Romanova, Marina M; Koldoba, Alexander V

    2014-01-01

    Counter-rotating discs can arise from the accretion of a counter-rotating gas cloud onto the surface of an existing co-rotating disc or from the counter-rotating gas moving radially inward to the outer edge of an existing disc. At the interface, the two components mix to produce gas or plasma with zero net angular momentum which tends to free-fall towards the disc center. We discuss high-resolution axisymmetric hydrodynamic simulations of a viscous counter-rotating disc for cases where the two components are vertically separated and radially separated. The viscosity is described by an isotropic $\\alpha-$viscosity including all terms in the viscous stress tensor. For the vertically separated components a shear layer forms between them. The middle of this layer free-falls to the disk center. The accretion rates are increased by factors $\\sim 10^2-10^4$ over that of a conventional disc rotating in one direction with the same viscosity. The vertical width of the shear layer and the accretion rate are strongly dep...

  18. The Eros of Counter Education

    Science.gov (United States)

    Luzon, Pinhas

    2016-01-01

    Erotic Counter Education (ECE) is the educational position of the late Ilan Gur-Ze'ev. In ECE Gur-Ze'ev combines two opposing positions in the philosophy of education, one teleological and anti-utopian, the other teleological and utopian. In light of this unique combination, I ask what mediates between these two poles and suggest that the answer…

  19. Laser sputter neutral mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    King, B.V.; Clarke, M.; Hu, H.; Betz [Newcastle Univ., NSW (Australia). Dept. of Physics

    1993-12-31

    Laser sputter neutral mass spectrometry (LSNMS) is an emerging technique for highly sensitive surface analysis. In this technique a target is bombarded with a pulsed beam of keV ions. The sputtered particles are intercepted by a high intensity pulsed laser beam above the surface and ionised with almost 100% efficiency. The photions may then be mass analysed using a quadrupole or, more commonly, using time of flight (TOF) techniques. In this method photoions are extracted from the ionisation region, accelerated to a known energy E{sub o} and strike a channelplate detector a distance `d` away. The flight time `t` of the photoions is then related to their mass by `d` {radical}m / {radical} 2E{sub o} so measurement of `t` allows mass spectra to be obtained. It is found that LSNMS is an emerging technique of great sensitivity and flexibility, useful for both applied analysis and to investigate basic sputtering processes. 4 refs., 3 figs.

  20. Method and apparatus for laser-controlled proton beam radiology

    Science.gov (United States)

    Johnstone, Carol J.

    1998-01-01

    A proton beam radiology system provides cancer treatment and proton radiography. The system includes an accelerator for producing an H.sup.- beam and a laser source for generating a laser beam. A photodetachment module is located proximate the periphery of the accelerator. The photodetachment module combines the H.sup.- beam and laser beam to produce a neutral beam therefrom within a subsection of the H.sup.- beam. The photodetachment module emits the neutral beam along a trajectory defined by the laser beam. The photodetachment module includes a stripping foil which forms a proton beam from the neutral beam. The proton beam is delivered to a conveyance segment which transports the proton beam to a patient treatment station. The photodetachment module further includes a laser scanner which moves the laser beam along a path transverse to the cross-section of the H.sup.- beam in order to form the neutral beam in subsections of the H.sup.- beam. As the scanning laser moves across the H.sup.- beam, it similarly varies the trajectory of the proton beam emitted from the photodetachment module and in turn varies the target location of the proton beam upon the patient. Intensity modulation of the proton beam can also be achieved by controlling the output of the laser.

  1. Basic Research Needs for Countering Terrorism

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, W.; Michalske, T.; Trewhella, J.; Makowski, L.; Swanson, B.; Colson, S.; Hazen, T.; Roberto, F.; Franz, D.; Resnick, G.; Jacobson, S.; Valdez, J.; Gourley, P.; Tadros, M.; Sigman, M.; Sailor, M.; Ramsey, M.; Smith, B.; Shea, K.; Hrbek, J.; Rodacy, P.; Tevault, D.; Edelstein, N.; Beitz, J.; Burns, C.; Choppin, G.; Clark, S.; Dietz, M.; Rogers, R.; Traina, S.; Baldwin, D.; Thurnauer, M.; Hall, G.; Newman, L.; Miller, D.; Kung, H.; Parkin, D.; Shuh, D.; Shaw, H.; Terminello, L.; Meisel, D.; Blake, D.; Buchanan, M.; Roberto, J.; Colson, S.; Carling, R.; Samara, G.; Sasaki, D.; Pianetta, P.; Faison, B.; Thomassen, D.; Fryberger, T.; Kiernan, G.; Kreisler, M.; Morgan, L.; Hicks, J.; Dehmer, J.; Kerr, L.; Smith, B.; Mays, J.; Clark, S.

    2002-03-01

    To identify connections between technology needs for countering terrorism and underlying science issues and to recommend investment strategies to increase the impact of basic research on efforts to counter terrorism.

  2. Neutral Buoyancy Laboratory (NBL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Neutral Buoyancy Laboratory (NBL) is an astronaut training facility and neutral buoyancy pool operated by NASA and located at the Sonny Carter Training Facility,...

  3. Low Emittance Growth in a LEBT with Un-Neutralized Section

    Energy Technology Data Exchange (ETDEWEB)

    Prost, Lionel [Fermilab; Carneiro, Jean-Paul [Fermilab; Shemyakin, Alexander [Fermilab

    2016-06-01

    In a Low Energy Beam Transport line (LEBT), the emittance growth due to the beam's own space charge is typically suppressed by way of neutralization from either electrons or ions, which originate from ionization of the background gas. In cases where the beam is chopped, the neutralization pattern changes throughout the beginning of the pulse, causing the Twiss parameters to differ significantly from their steady state values, which, in turn, may result in beam losses downstream. For a modest beam perveance, there is an alternative solution, in which the beam is kept un-neutralized in the portion of the LEBT that contains the chopper. The emittance can be nearly preserved if the transition to the un-neutralized section occurs where the beam exhibits low transverse tails. This report discusses the experimental realization of such a scheme at Fermilab's PXIE, where low beam emittance dilution was demonstrated

  4. 中性束注入在EAST中激发的离散阿尔文不稳定性%Neutral beam injection induced discrete Alfv´en instabilities on experimental advanced superconducting tokamak∗

    Institute of Scientific and Technical Information of China (English)

    王军; 胡纯栋; 胡双辉; 吴斌; 丁斯晔; 王进芳

    2013-01-01

    The neutral beam injection (NBI) system is applied to the experimental advanced superconducting tokamak (EAST). It will excite some Alfv´en instabilities when the plasma characteristics are improved. The numerical research on the NBI-induced discrete Alfv´en eigenmode (αTAE) and toroidal effect-induced Alfv´en eigenmode (TAE) in the pedestal region is presented in the paper. The research results show that plenty ofαTAEs appear in this region. TheαTAE is very different from the TAE. These modes are trapped by theα-induced potential wells along the magnetic field line. Due to negligible continuum damping via wave energy tunneling, similar to TAE, theαTAE can also be readily destabilized by energetic particles. Differently,αTAE frequency spectrum is more broad than TAE, and they are existed not only inside the gap but also outside the gap. The growth rate increases with injected power increasing. This instability maybe affects the physical behavior of the tokamak and the confinement of the plasma.%  中性束加热将应用于先进实验超导托卡马克装置中,在改善等离子性能的同时也会激发起多种阿尔文不稳定性。本文主要采用了数值模拟的方法在理论上研究了中性束注入时在台基区激发的离散阿尔文本征模(αTAE)和环效应阿尔文本征模(TAE),结果表明在这个区域会激发出丰富的离散阿尔文不稳定性,这种离散阿尔文不稳定性不同于传统的TAE,这种模式是俘获在气球模驱动势阱中的束缚态,由于气球模势阱的存在使它和连续谱解耦,从势阱中漏出去的能量可以忽略不计,和TAE类似都很容易被激发,这种模式可以存在于gap内,也可以存在于gap外,频谱更宽泛。注入功率越大这种不稳定性增长率越大。这种不稳定性可能会影响等离子体的物理行为,从而影响等离子体的约束。

  5. Toxic emissions and devaluated CO2-neutrality

    DEFF Research Database (Denmark)

    Czeskleba-Dupont, Rolf

    with a climate policy whose goals of CO2-reduction were made operational by green-wash. Arguments are given for the devaluation of CO2- neutrality in case of burning wood. Alternative practices as storing C in high quality wood products and/or leaving wood in the forest are recommended. A counter......-productive effect of dioxin formation in the cooling phase of wood burning appliances has been registered akin to de-novo-synthesis in municipal solid waste incinerators. Researchers, regulators and the public are, however, still preoccupied by notions of oven design and operation parameters, assuming that dioxin...

  6. Counter-discourse in Zimbabwean literature

    NARCIS (Netherlands)

    Mangena, Tendai

    2015-01-01

    Counter-Discourse in Zimbabwean Literature is a study of specific aspects of counter-discursive Zimbabwean narratives in English. In discussing the selected texts, my thesis is based on Terdiman’s (1989) the postcolonial concept of counter-discourse. In Zimbabwean literature challenges to a dominant

  7. Lossy Counter Machines Decidability Cheat Sheet

    Science.gov (United States)

    Schnoebelen, Philippe

    Lossy counter machines (LCM's) are a variant of Minsky counter machines based on weak (or unreliable) counters in the sense that they can decrease nondeterministically and without notification. This model, introduced by R. Mayr [TCS 297:337-354 (2003)], is not yet very well known, even though it has already proven useful for establishing hardness results.

  8. Science Experimenter: Experimenting with a Geiger Counter.

    Science.gov (United States)

    Mims, Forrest M., III

    1992-01-01

    Describes the use of geiger counters for scientific investigations and experiments. Presents information about background radiation, its sources and detection. Describes how geiger counters work and other methods of radiation detection. Provides purchasing information for geiger counters, related computer software and equipment. (MCO)

  9. Counter-discourse in Zimbabwean literature

    NARCIS (Netherlands)

    Mangena, Tendai

    2015-01-01

    Counter-Discourse in Zimbabwean Literature is a study of specific aspects of counter-discursive Zimbabwean narratives in English. In discussing the selected texts, my thesis is based on Terdiman’s (1989) the postcolonial concept of counter-discourse. In Zimbabwean literature challenges to a dominant

  10. Counter-Rotation in Disk Galaxies

    CERN Document Server

    Corsini, E M

    2014-01-01

    Counter-rotating galaxies host two components rotating in opposite directions with respect to each other. The kinematic and morphological properties of lenticulars and spirals hosting counter-rotating components are reviewed. Statistics of the counter-rotating galaxies and analysis of their stellar populations provide constraints on the formation scenarios which include both environmental and internal processes.

  11. Counter unmanned aerial system testing and evaluation methodology

    Science.gov (United States)

    Kouhestani, C.; Woo, B.; Birch, G.

    2017-05-01

    Unmanned aerial systems (UAS) are increasing in flight times, ease of use, and payload sizes. Detection, classification, tracking, and neutralization of UAS is a necessary capability for infrastructure and facility protection. We discuss test and evaluation methodology developed at Sandia National Laboratories to establish a consistent, defendable, and unbiased means for evaluating counter unmanned aerial system (CUAS) technologies. The test approach described identifies test strategies, performance metrics, UAS types tested, key variables, and the necessary data analysis to accurately quantify the capabilities of CUAS technologies. The tests conducted, as defined by this approach, will allow for the determination of quantifiable limitations, strengths, and weaknesses in terms of detection, tracking, classification, and neutralization. Communicating the results of this testing in such a manner informs decisions by government sponsors and stakeholders that can be used to guide future investments and inform procurement, deployment, and advancement of such systems into their specific venues.

  12. Evidence for neutral-current diffractive neutral pion production from hydrogen in neutrino interactions on hydrocarbon

    CERN Document Server

    Wolcott, J; Altinok, O; Bercellie, A; Betancourt, M; Bodek, A; Bravar, A; Budd, H; Cai, T; Carneiro, M F; Chvojka, J; Devan, J; Dytman, S A; Diaz, G A; Eberly, B; Endress, E; Felix, J; Fields, L; Galindo, R; Gallagher, H; Golan, T; Gran, R; Harris, D A; Higuera, A; Hurtado, K; Kiveni, M; Kleykamp, J; Kordosky, M; Le, T; Maher, E; Manly, S; Mann, W A; Marshall, C M; Caicedo, D A Martinez; McFarland, K S; McGivern, C L; McGowan, A M; Messerly, B; Miller, J; Mislivec, A; Morfin, J G; Mousseau, J; Naples, D; Nelson, J K; Norrick, A; Nuruzzaman,; Paolone, V; Park, J; Patrick, C E; Perdue, G N; Rakotondravohitra, L; Ramirez, M A; Ray, H; Ren, L; Rimal, D; Rodrigues, P A; Ruterbories, D; Schellman, H; Schmitz, D W; Salinas, C J Solano; Sanchez, S F; Tagg, N; Tice, B G; Valencia, E; Walton, T; Wospakrik, M; Zhang, D

    2016-01-01

    The MINERvA experiment observes an excess of events containing electromagnetic showers relative to the expectation from Monte Carlo simulations in neutral-current neutrino interactions with mean beam energy of 4.5 GeV on a hydrocarbon target. The excess is characterized and found to be consistent with neutral-current neutral pion production with a broad energy distribution peaking at 7 GeV and a total cross section of 0.26 +- 0.02 (stat) +- 0.08 (sys) x 10^{-39} cm^{2}. The angular distribution, electromagnetic shower energy, and spatial distribution of the energy depositions of the excess are consistent with expectations from neutrino neutral-current diffractive neutral pion production from hydrogen in the hydrocarbon target. These data comprise the first direct experimental observation and constraint for a reaction that poses an important background process in neutrino oscillation experiments searching for muon neutrino to electron neutrino oscillations.

  13. Science role in countering terrorism

    Science.gov (United States)

    Showstack, Randy

    Geoscience expertise figures as a component of a new report on harnessing the U.S. science and technology community in the fight against terrorism.The National Research Council report, "Making the Nation Safer: The Role of Science and Technology in Countering Terrorism," proposes research agendas in a number of areas perceived to be vulnerable to terrorism. These areas include nuclear and radiological threats, toxic chemicals and explosive materials, information technology, energy systems, and cities and fixed infrastructure.

  14. Short-pulse, high-energy radiation generation from laser-wakefield accelerated electron beams

    Science.gov (United States)

    Schumaker, Will

    2013-10-01

    Recent experimental results of laser wakefield acceleration (LWFA) of ~GeV electrons driven by the 200TW HERCULES and the 400TW ASTRA-GEMINI laser systems and their subsequent generation of photons, positrons, and neutrons are presented. In LWFA, high-intensity (I >1019 W /cm2), ultra-short (τL Z target via bremsstrahlung into low-divergence (Z, the resulting Ne+ /Ne- ratio can approach unity, resulting in a near neutral density plasma jet. These quasi-neutral beams are presumed to retain the short-pulse (τL characteristic of the electron beam, resulting in a high peak density of ne- /e+ ~ 1016 cm-3 , making the source an excellent candidate for laboratory study of astrophysical leptonic jets. Alternatively, the electron beam can be interacted with a counter-propagating, ultra-high intensity (I >1021 W /cm2) laser pulse to undergo inverse Compton scattering and emit a high-peak brightness beam of high-energy photons. Preliminary results and experimental sensitivities of the electron-laser beam overlap are presented. The high-energy photon beams can be spectrally resolved using a forward Compton scattering spectrometer. Moreover, the photon flux can be characterized by a pixelated scintillator array and by nuclear activation and (γ,n) neutron measurements from the photons interacting with a secondary solid target. Monte-Carlo simulations were performed using FLUKA to support the yield estimates. This research was supported by DOE/NSF-PHY 0810979, NSF CAREER 1054164, DARPA AXiS N66001-11-1-4208, SF/DNDO F021166, and the Leverhulme Trust ECF-2011-383.

  15. Simulation of beam-induced plasma for the mitigation of beam-beam effects

    Energy Technology Data Exchange (ETDEWEB)

    Ma, J.; Wang, G.; Samulyak, R.; Yu, K.; Litvinenko, V.

    2015-05-03

    One of the main challenges in the increase of luminosity of circular colliders is the control of the beam-beam effect. In the process of exploring beam-beam mitigation methods using plasma, we evaluated the possibility of plasma generation via ionization of neutral gas by proton beams, and performed highly resolved simulations of the beam-plasma interaction using SPACE, a 3D electromagnetic particle-in-cell code. The process of plasma generation is modelled using experimentally measured cross-section coefficients and a plasma recombination model that takes into account the presence of neutral gas and beam-induced electromagnetic fields. Numerically simulated plasma oscillations are consistent with theoretical analysis. In the beam-plasma interaction process, high-density neutral gas reduces the mean free path of plasma electrons and their acceleration. A numerical model for the drift speed as a limit of plasma electron velocity was developed. Simulations demonstrate a significant reduction of the beam electric field in the presence of plasma. Preliminary simulations using fully-ionized plasma have also been performed and compared with the case of beam-induced plasma.

  16. A Novel Gravito-Optical Surface Trap for Neutral Atoms

    Institute of Scientific and Technical Information of China (English)

    XIE Chun-Xia; WANG Zhengling; YIN Jian-Ping

    2006-01-01

    @@ We propose a novel gravito-optical surface trap (GOST) for neutral atoms based on one-dimensional intensity gradient cooling. The surface optical trap is composed of a blue-detuned reduced semi-Gaussian laser beam (SGB), a far-blue-detuned dark hollow beam and the gravity field.

  17. High-energy tritium beams as current drivers in tokamak reactors

    Energy Technology Data Exchange (ETDEWEB)

    Mikkelsen, D.R.; Grisham, L.R.

    1983-04-01

    The effect on neutral-beam design and reactor performance of using high-energy (approx. 3-10 MeV) tritium neutral beams to drive steady-state tokamak reactors is considered. The lower current of such beams leads to several advantages over lower-energy neutral beams. The major disadvantage is the reduction of the reactor output caused by the lower current-drive efficiency of the high-energy beams.

  18. Theoretical and Experimental Beam Plasma Physics (TEBPP)

    Science.gov (United States)

    Roberts, B.

    1986-01-01

    The theoretical and experimental beam plasma physics (TEBPP) consists of a package of five instruments to measure electric and magnetic fields, plasma density and temperature, neutral density, photometric emissions, and energetic particle spectra during firings of the particle injector (SEPAC) electron beam. The package is developed on a maneuverable boom (or RMS) and is used to measure beam characteristics and induced perturbations field ( 10 m) and mid field ( 10 m to 100 m) along the electron beam. The TEBPP package will be designed to investigate induced oscillations and induced electromagnetic mode waves, neutral and ion density and temperature effects, and beam characteristics as a function of axial distance.

  19. Stable counter-rotating vortex pairs in saturable media

    Energy Technology Data Exchange (ETDEWEB)

    Desyatnikov, Anton S. [Nonlinear Physics Centre, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200 (Australia)]. E-mail: asd124@rsphysse.anu.edu.au; Mihalache, Dumitru [Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), Department of Theoretical Physics, 407 Atomistilor, Magurele-Bucharest 077125 (Romania); Mazilu, Dumitru [Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), Department of Theoretical Physics, 407 Atomistilor, Magurele-Bucharest 077125 (Romania); Malomed, Boris A. [Department of Interdisciplinary Studies, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Lederer, Falk [Institute of Solid State Theory and Theoretical Optics, Friedrich-Schiller Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany)

    2007-04-30

    We resolve a controversial issue of the stability of composite vortex solitons in self-focusing saturable nonlinear media. Stable vortex solitons with hidden angular momentum, i.e., composed of counter-rotating beams with topological charges +1 and -1, are found, and their linear-stability region is identified. In contrast, the solitons with explicit vorticity are always unstable against splitting. The predicted linear stability of the hidden-vorticity solitons is achieved in the strong-saturation regime, when the soliton's total power exceeds a certain threshold. The dynamical stability is verified in direct simulations of nonlinear model.

  20. Filamentation instability in two counter-streaming laser plasmas

    Science.gov (United States)

    Liu, Hui; Dong, Quan-Li; Yuan, Da-Wei; Liu, Xun; Hua, Neng; Qiao, Zhan-Feng; Zhu, Bao-Qiang; Zhu, Jian-Qiang; Jiang, Bo-Bin; Du, Kai; Tang, Yong-Jian; Zhao, Gang; Yuan, Xiao-Hui; Sheng, Zheng-Ming; Zhang, Jie

    2016-12-01

    The filamentation instability was observed in the interaction of two counter-streaming laser ablated plasma flows, which were supersonic, collisionless, and also closely relevant to astrophysical conditions. The plasma flows were created by irradiating a pair of oppositely standing plastic (CH) foils with 1ns-pulsed laser beams of total energy of 1.7 kJ in two laser spots. With characteristics diagnosed in experiments, the calculated features of Weibel-type filaments are in good agreement with measurements. Project supported by the National Natural Science Foundation of China (Grant Nos. 11074297, 11674146, and 11220101002) and the National Basic Research Program of China (Grant No. 2013CBA01500.

  1. Direct CP violation in neutral kaon decays

    Indian Academy of Sciences (India)

    Wojciech Wiślicki

    2004-03-01

    The final result of the NA48 experiment is presented and performed at the CERN SPS neutral kaon beams, on the direct CP violation parameter Re$('/)$, as measured from the decay rates of neutral kaons into two pions. The data collected in the years 1997-2001 yield the evidence for the direct CP violation with Re$('/)=(14.7± 2.2)× 10^{-4}$. Description of experimental method and systematics, comparison with the corresponding FNAL result and discussion of some implications for the theory are given.

  2. Dielectric barrier discharge source for supersonic beams

    Energy Technology Data Exchange (ETDEWEB)

    Luria, K.; Lavie, N.; Even, U. [Sackler School of Chemistry, Tel Aviv University, Tel Aviv 69978 (Israel)

    2009-10-15

    We present a new excitation source for pulsed supersonic beams. The excitation is based on dielectric barrier discharge in the beam. It produces cold beams of metastable atoms, dissociated neutral atoms from molecular precursors, and both positive and negative ions with high efficiency and reliability.

  3. Study of the upper atmosphere observation by artificial ion beam

    OpenAIRE

    Sugimoto, Sachiko; Kuninaka, Hitoshi; TOKI, Kyoichiro; Arakawa, Yoshihiro; 杉本 幸子; 國中 均; 都木 恭一郎; 荒川 義博

    2005-01-01

    The observing method that uses ENA (Energetic Neutral Atoms), produced by ion beam injected from an ion thruster, is studied and researched in order to estimate the density of neutral particles in the upper atmosphere. The ion beam experiences charge exchange collision (CEX) with neighboring neutral particles to transform into ENAs. The ENA preserves the information about the particles concerned with those collisions. A new method of estimating the density and the composition of the neutral p...

  4. Active Beam Spectroscopy

    Science.gov (United States)

    von Hellermann, M. G.; Delabie, E.; Jaspers, R. J. E.; Biel, W.; Marchuk, O.; Summers, H. P.; Whiteford, A.; Giroud, C.; Hawkes, N. C.; Zastrow, K. D.

    2008-03-01

    Charge eXchange Recombination Spectroscopy (CXRS) plays a pivotal role in the diagnostics of hot fusion plasmas and is implemented currently in most of the operating devices. In the present report the main features of CXRS are summarized and supporting software packages encompassing "Spectral Analysis Code CXSFIT", "Charge Exchange Analysis Package CHEAP", and finally "Forward Prediction of Spectral Features" are described. Beam Emission Spectroscopy (BES) is proposed as indispensable cross-calibration tool for absolute local impurity density measurements and also for the continuous monitoring of the neutral beam power deposition profile. Finally, a full exploitation of the `Motional Stark Effect' pattern is proposed to deduce local pitch angles, total magnetic fields and possibly radial electric fields. For the proposed active beam spectroscopy diagnostic on ITER comprehensive performance studies have been carried out. Estimates of expected spectral signal-to-noise ratios are based on atomic modelling of neutral beam stopping and emissivities for CXRS, BES and background continuum radiation as well as extrapolations from present CXRS diagnostic systems on JET, Tore Supra, TEXTOR and ASDEX-UG. Supplementary to thermal features a further promising application of CXRS has been proposed recently for ITER, that is a study of slowing-down alpha particles in the energy range up to 2 MeV making use of the 100 keV/amu DNB (Diagnostic Neutral Beam) and the 500 keV/amu HNB (Heating Neutral Beam). Synthetic Fast Ion Slowing-Down spectra are evaluated in terms of source rates and slowing-down parameters

  5. The transparent microstrip gas counter

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hiroyuki, E-mail: leo@q.t.u-tokyo.ac.j [University of Tokyo, Tokyo 113-8656 (Japan); Fujita, Kaoru; Fujiwara, Takeshi [University of Tokyo, Tokyo 113-8656 (Japan); Niko, Hisako; Guerard, Bruno [Institute of Max von Laue and Paul Langevin, BP 156, 38042 Grenoble, Cedex 9 (France); Fraga, Francisco [Departamento de Fisica, LIP-Coimbra, Universidade de Coimbra, 3000 Coimbra (Portugal); Iyomoto, Naoko [University of Tokyo, Tokyo 113-8656 (Japan)

    2010-11-01

    Conventional MSGCs are made of metal electrodes that might absorb or reflect optical photons. If the electrodes are made of transparent material like ITO, we could take advantage of optical readout. A gas scintillation proportional counter made of ITO MSGC is fabricated and tested where both optical and charge signals are obtained. We have selected a multi-grid structure that can avoid charge-up problem with normal transparent glass substrate. Test results with Ar and CF{sub 4} gas mixture showed a stable gas gain of {approx}2800 and {approx}110 optical photons for 6 keV X-rays. Position sensing with PSPMT has successfully been demonstrated.

  6. COUNTER-TERRORISM IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Jordan Sebastian Meliala

    2015-04-01

    Full Text Available Since the incident of World Trade Center (WTC in USA, Indonesia has become an easy target for the next terrorism. Counterterrorist campaigns can be undertaken by military and paramilitary forces. Counterterrorism refers to proactive policies that specifically seek to eliminate terrorist environments and groups, Regardless of which policy is selected, the ultimate goal of counterterrorism is clear: to save lives by proactively preventing or decreasing the number of terrorist attacks. But, so far the Government of Indonesia is only able to capture the terrorists but is unable to eradicate terrorism. Therefore, the government of Indonesia still needs a comprehensive ways to counter terrorism in Indonesia

  7. Condensation Particle Counter Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Kuang, C. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-02-01

    The Model 3772 CPC is a compact, rugged, and full-featured instrument that detects airborne particles down to 10 nm in diameter, at an aerosol flow rate of 1.0 lpm, over a concentration range from 0 to 1x104 #/cc. This CPC is ideally suited for applications without high concentration measurements, such as basic aerosol research, filter and air-cleaner testing, particle counter calibrations, environmental monitoring, mobile aerosol studies, particle shedding and component testing, and atmospheric and climate studies.

  8. Installation and Operation of the SNO Neutral Current Detector Array

    Science.gov (United States)

    SNO Collaboration; McGee, S.; Rielage, K.

    2005-06-01

    An array of low background detectors designed to capture neutrons liberated by interactions with solar neutrinos was recently installed in the heavy water region of the SNO experiment. The neutral current detector (NCD) array consists of 36 proportional counters filled with 3He-CF4 gas and 4 proportional counters filled with 4He-CF4. Special hardware conforming to the high radiopurity requirements in SNO was used to assemble and deploy these counters. Neutron events detected by the NCD array are distinguished from various types of backgrounds on an event-by-event basis using the NCD data acquisition system (NCDDAQ), which employs a mixture of commercial and custom-built electronics equipment. The NCDDAQ is controlled by a custom-built Object-oriented Realtime Control and Acquisition (ORCA) software program, and is fully integrated into the SNO PMT data acquisition system to provide shared trigger information and a combined data stream.

  9. Installation and Operation of the SNO Neutral Current Detector Array

    Energy Technology Data Exchange (ETDEWEB)

    Heise, J. [Physics Division, Los Alamos National Laboratory, Los Alamos, NM, 87545 (United States); McGee, S. [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA, 98195 (United States); Rielage, K. [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA, 98195 (United States)

    2005-06-15

    An array of low background detectors designed to capture neutrons liberated by interactions with solar neutrinos was recently installed in the heavy water region of the SNO experiment. The neutral current detector (NCD) array consists of 36 proportional counters filled with {sup 3}He-CF{sub 4} gas and 4 proportional counters filled with {sup 4}He-CF{sub 4}. Special hardware conforming to the high radiopurity requirements in SNO was used to assemble and deploy these counters. Neutron events detected by the NCD array are distinguished from various types of backgrounds on an event-by-event basis using the NCD data acquisition system (NCDDAQ), which employs a mixture of commercial and custom-built electronics equipment. The NCDDAQ is controlled by a custom-built Object-oriented Realtime Control and Acquisition (ORCA) software program, and is fully integrated into the SNO PMT data acquisition system to provide shared trigger information and a combined data stream.

  10. Calibration of the Neutral Current Detection Array in the SNO experiment

    Energy Technology Data Exchange (ETDEWEB)

    Cox, G.A. [University of Washington, Seattle, US (United States); Cleveland, B.T. [University of Oxford, Oxford (United Kingdom); Di Marco, M. [Queen' s University, Kingston (Canada); present address: University of Geneva, Geneva (Switzerland); Evans, H.C.; Guillian, E.; Hallin, A.L. [Queen' s University, Kingston (Canada); Huang, M. [University of Texas, Austin (United States); Howard, C. [Queen' s University, Kingston (Canada); Jelley, N.A. [University of Oxford, Oxford (United Kingdom); Law, J. [University of Guelph, Guelph (Canada); Loach, J.C. [University of Oxford, Oxford (United Kingdom); Lawrence Berkeley National Laboratory, Berkeley (United States); O' Keeffe, H.M. [University of Oxford, Oxford (United Kingdom); Kraus, C.; Krauss, C.B. [Queen' s University, Kingston (Canada); McGee, S. [present address: University of Geneva, Geneva, Switserland (Switzerland); Peeters, S.J.M., E-mail: s.peeters1@physics.ox.ac.uk [University of Oxford, Oxford (United Kingdom); Prior, G. [University of Texas, Austin (United States); Lawrence Berkeley National Laboratory, Berkeley (United States); Rielage, K. [Los Alamos National Laboratory, Los Alamos (United States); Reitzner, D. [University of Guelph, Guelph (Canada); Skensved, P. [Queen' s University, Kingston (Canada); and others

    2011-12-15

    Since November 25th, 2004, the Sudbury Neutrino Observatory has been taking production data in its third and final phase. For this phase a 'Neutral-Current Detection (NCD) Array', consisting of 36 strings of {sup 3}He proportional counters and 4 strings of {sup 4}He proportional counters, was deployed in SNO's D{sub 2}O volume. It supplements the Cherenkov detector, consisting of 9456 photomultiplier tubes, present in the previous two phases by offering an independent measurement of the solar neutral current rate. The {sup 3}He counters detect neutrons from neutrino-deuteron neutral current interactions in the D{sub 2}O. We describe the calibration of this array.

  11. Laser-induced positive ion and neutral atom/molecule emissions from single-crystal CaHPO4 center dot 2H20: The role of electron-beam-induced defects

    Energy Technology Data Exchange (ETDEWEB)

    Dawes, Mary L.(Washington State University); Hess, Wayne P.(BATTELLE (PACIFIC NW LAB)); Kawaguchi, Yuji (VISITORS); Langford, S C.(Washington State University); Dickinson, J. Tom (Washington State University)

    1998-11-01

    We examine laser-induced ion and neutral emissions from single-crystal CaHPO4 center dot 2H2O (brushite), a wide-band-gap, hydrated inorganic single crystal, with 248-nm excimer laser radiation. Both laser-induced ion and neutral emissions are several orders magnitude higher following exposure to 2keV electrons at current densities of 200 uA/cm2 and doses of 1 C/cm2. In addition to intense Ca+ signals, electron-irradiated surfaces yield substantial CaO+, PO+, and P+ signals. As-grown and as-cleaved brushite show only weak neutral O2 and Ca emissions, whereas electron-irradiated surfaces yield enhanced O2, Ca, PO, PO2, and P emissions. Electron irradiation (i) significantly heats the sample, leading to thermal dehydration (CaHPO4 formation) and pyrolysis (Ca2P2O7 formation)and (ii) chemically reduces the surface via electron stimulated desorption. The thermal effects are accompanied by morphological changes, including recrystallization. Although complex, these changes lead to high defect densities, which are responsible for the dramatic enhancements in the observed laser desorption.

  12. Laser-induced positive ion and neutral atom/molecule emission from single-crystal CaHPO4.2H2O: The role of electron-beam-induced defects

    Science.gov (United States)

    Dawes, M. L.; Hess, W.; Kawaguchi, Y.; Langford, S. C.; Dickinson, J. T.

    We examine laser-induced ion and neutral emissions from single-crystal CaHPO4.2H2O (brushite), a wide-band-gap, hydrated inorganic single crystal, with 248-nm excimer laser radiation. Both laser-induced ion and neutral emissions are several orders of magnitude higher following exposure to 2 keV electrons at current densities of 200 μA/cm2 and doses of 1 C/cm2. In addition to intense Ca+ signals, electron-irradiated surfaces yield substantial CaO+, PO+, and P+ signals. As-grown and as-cleaved brushite show only weak neutral O2 and Ca emissions, whereas electron-irradiated surfaces yield enhanced O2, Ca, PO, PO2, and P emissions. Electron irradiation (i) significantly heats the sample, leading to thermal dehydration (CaHPO4 formation) and pyrolysis (Ca2P2O7 formation) and (ii) chemically reduces the surface via electron stimulated desorption. The thermal effects are accompanied by morphological changes, including recrystallization. Although complex, these changes lead to high defect densities, which are responsible for the dramatic enhancements in the observed laser desorption.

  13. Design and test of an extremely high resolution Timing Counter for the MEG II experiment: preliminary results

    CERN Document Server

    De Gerone, M; Ootani, W; Uchiyama, Y; Nishimura, M; Shirabe, S; Cattaneo, P W; Rossella, M

    2013-01-01

    The design and tests of Timing Counter elements for the upgrade of the MEG experiment, MEG II,is presented. The detector is based on several small plates of scintillator with a Silicon PhotoMultipliers dual-side readout. The optimisation of the single counter elements (SiPMs, scintillators, geometry) is described. Moreover, the results obtained with a first prototype tested at the Beam Test Facility (BTF) of the INFN Laboratori Nazionali di Frascati (LNF) are presented.

  14. Neutralization of English Consonants

    Institute of Scientific and Technical Information of China (English)

    庞彬彬

    2011-01-01

    This paper gives a brief account of English consonant cluster's structure and phonetic features from the perspective of the definition and cause of neutralization of English consonants as well as their distinctive features and oppositions.It comes up with the final conclusion that neutralization exists in only thirteen English consonant clusters,among a large number of consonant clusters.

  15. Characterization of an INVS Model IV Neutron Counter for High Precision ($\\gamma,n$) Cross-Section Measurements

    CERN Document Server

    Arnold, C W; Karwowski, H J; Rich, G C; Tompkins, J R; Howell, C R

    2010-01-01

    A neutron counter designed for assay of radioactive materials has been adapted for beam experiments at TUNL. The cylindrical geometry and 64% maximum efficiency make it well suited for ($\\gamma,n$) cross-section measurements near the neutron emission threshold. A high precision characterization of the counter has been made using neutrons from several sources. Using a combination of measurements and simulations, the absolute detection efficiency of the neutron counter was determined to an accuracy of $\\pm$ 3% in the neutron energy range between 0.1 and 1 MeV. It is shown that this efficiency characterization is generally valid for a wide range of targets.

  16. Particle identification performance of the prototype aerogel RICH counter for the Belle II experiment

    Science.gov (United States)

    Iwata, S.; Adachi, I.; Hara, K.; Iijima, T.; Ikeda, H.; Kakuno, H.; Kawai, H.; Kawasaki, T.; Korpar, S.; Križan, P.; Kumita, T.; Nishida, S.; Ogawa, S.; Pestotnik, R.; Šantelj, L.; Seljak, A.; Sumiyoshi, T.; Tabata, M.; Tahirovic, E.; Yusa, Y.

    2016-03-01

    We have developed a new type of particle identification device, called an aerogel ring imaging Cherenkov (ARICH) counter, for the Belle II experiment. It uses silica aerogel tiles as Cherenkov radiators. For detection of Cherenkov photons, hybrid avalanche photo-detectors (HAPDs) are used. The designed HAPD has a high sensitivity to single photons under a strong magnetic field. We have confirmed that the HAPD provides high efficiency for single-photon detection even after exposure to neutron and γ -ray radiation that exceeds the levels expected in the 10-year Belle II operation. In order to confirm the basic performance of the ARICH counter system, we carried out a beam test at the using a prototype of the ARICH counter with six HAPD modules. The results are in agreement with our expectations and confirm the suitability of the ARICH counter for the Belle II experiment. Based on the in-beam performance of the device, we expect that the identification efficiency at 3.5 GeV/c is 97.4% and 4.9% for pions and kaons, respectively. This paper summarizes the development of the HAPD for the ARICH and the evaluation of the performance of the prototype ARICH counter built with the final design components.

  17. Methods for neutralizing anthrax or anthrax spores

    Science.gov (United States)

    Sloan, Mark A; Vivekandanda, Jeevalatha; Holwitt, Eric A; Kiel, Johnathan L

    2013-02-26

    The present invention concerns methods, compositions and apparatus for neutralizing bioagents, wherein bioagents comprise biowarfare agents, biohazardous agents, biological agents and/or infectious agents. The methods comprise exposing the bioagent to an organic semiconductor and exposing the bioagent and organic semiconductor to a source of energy. Although any source of energy is contemplated, in some embodiments the energy comprises visible light, ultraviolet, infrared, radiofrequency, microwave, laser radiation, pulsed corona discharge or electron beam radiation. Exemplary organic semiconductors include DAT and DALM. In certain embodiments, the organic semiconductor may be attached to one or more binding moieties, such as an antibody, antibody fragment, or nucleic acid ligand. Preferably, the binding moiety has a binding affinity for one or more bioagents to be neutralized. Other embodiments concern an apparatus comprising an organic semiconductor and an energy source. In preferred embodiments, the methods, compositions and apparatus are used for neutralizing anthrax spores.

  18. Propagation of ion beams through a tenuous magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Chrien, E.F.; Valeo, E.J.; Kulsrud, R.M.; Oberman, C.R.

    1985-10-01

    When an ion beam is propagated through a plasma, the question of charge neutralization is critical to its propagation. We consider such a problem where the plasma is magnetized with magnetic field perpendicular to the beam. The plasma-number density and beam-number density are assumed comparable. We reduce the problem to a two-dimensional model, which we solve. The solution suggests that it should be possible to attain charge neutralization if the beam density is properly varied along itself.

  19. Experimental evidence of energetic neutrals production in an ion diode

    Energy Technology Data Exchange (ETDEWEB)

    Pushkarev, A.I., E-mail: aipush@mail.ru; Isakova, Y.I.; Khaylov, I.P.

    2015-01-15

    The paper presents several experimental proofs of the formation of energetic charge-exchange neutrals in a self-magnetically insulated ion diode with a graphite cathode. The energetic neutrals are thought to be produced as a result of charge exchange process between accelerated ions and stationary neutral molecules. The experiments have been carried out using both a diode with externally applied magnetic insulation (single-pulse mode: 100 ns, 250–300 kV) and a diode with self-magnetic insulation (double-pulse mode: 300–500 ns, 100–150 kV (negative pulse); 120 ns, 250–300 kV (positive pulse)). The motivation for looking at the neutral component of the ion beam came when we compared two independent methods to measure the energy density of the beam. A quantitative comparison of infrared measurements with signals from Faraday cups and diode voltage was made to assess the presence of neutral atoms in the ion beam. As another proof of charge-exchange effects in ion diode we present the results of statistical analysis of diode performance. It was found that the shot-to shot variation of the energy density in a set of 50–100 shots does not exceed 11%, whilst the same variation for ion current density was 20–30%; suggesting the presence of neutrals in the beam. Moreover, the pressure in the zone of ion beam energy dissipation exceeds the results stated in cited references. The difference between our experimental data and results stated by other authors we attribute to the presence of a low-energy charge-exchange neutral component in the ion beam.

  20. Implementation of a 3D halo neutral model in the TRANSP code and application to projected NSTX-U plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Medley, S. S. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Liu, D. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Univ. of California, Irvine, CA (United States). Dept. of Physics and Astronomy; Gorelenkova, M. V. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Heidbrink, W. W. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Univ. of California, Irvine, CA (United States). Dept. of Physics and Astronomy; Stagner, L. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Univ. of California, Irvine, CA (United States). Dept. of Physics and Astronomy

    2016-01-12

    A 3D halo neutral code developed at the Princeton Plasma Physics Laboratory and implemented for analysis using the TRANSP code is applied to projected National Spherical Torus eXperiment-Upgrade (NSTX-U plasmas). The legacy TRANSP code did not handle halo neutrals properly since they were distributed over the plasma volume rather than remaining in the vicinity of the neutral beam footprint as is actually the case. The 3D halo neutral code uses a 'beam-in-a-box' model that encompasses both injected beam neutrals and resulting halo neutrals. Upon deposition by charge exchange, a subset of the full, one-half and one-third beam energy components produce first generation halo neutrals that are tracked through successive generations until an ionization event occurs or the descendant halos exit the box. The 3D halo neutral model and neutral particle analyzer (NPA) simulator in the TRANSP code have been benchmarked with the Fast-Ion D-Alpha simulation (FIDAsim) code, which provides Monte Carlo simulations of beam neutral injection, attenuation, halo generation, halo spatial diffusion, and photoemission processes. When using the same atomic physics database, TRANSP and FIDAsim simulations achieve excellent agreement on the spatial profile and magnitude of beam and halo neutral densities and the NPA energy spectrum. The simulations show that the halo neutral density can be comparable to the beam neutral density. These halo neutrals can double the NPA flux, but they have minor effects on the NPA energy spectrum shape. The TRANSP and FIDAsim simulations also suggest that the magnitudes of beam and halo neutral densities are relatively sensitive to the choice of the atomic physics databases.

  1. Implementation of a 3D halo neutral model in the TRANSP code and application to projected NSTX-U plasmas

    Science.gov (United States)

    Medley, S. S.; Liu, D.; Gorelenkova, M. V.; Heidbrink, W. W.; Stagner, L.

    2016-02-01

    A 3D halo neutral code developed at the Princeton Plasma Physics Laboratory and implemented for analysis using the TRANSP code is applied to projected National Spherical Torus eXperiment-Upgrade (NSTX-U plasmas). The legacy TRANSP code did not handle halo neutrals properly since they were distributed over the plasma volume rather than remaining in the vicinity of the neutral beam footprint as is actually the case. The 3D halo neutral code uses a ‘beam-in-a-box’ model that encompasses both injected beam neutrals and resulting halo neutrals. Upon deposition by charge exchange, a subset of the full, one-half and one-third beam energy components produce first generation halo neutrals that are tracked through successive generations until an ionization event occurs or the descendant halos exit the box. The 3D halo neutral model and neutral particle analyzer (NPA) simulator in the TRANSP code have been benchmarked with the Fast-Ion D-Alpha simulation (FIDAsim) code, which provides Monte Carlo simulations of beam neutral injection, attenuation, halo generation, halo spatial diffusion, and photoemission processes. When using the same atomic physics database, TRANSP and FIDAsim simulations achieve excellent agreement on the spatial profile and magnitude of beam and halo neutral densities and the NPA energy spectrum. The simulations show that the halo neutral density can be comparable to the beam neutral density. These halo neutrals can double the NPA flux, but they have minor effects on the NPA energy spectrum shape. The TRANSP and FIDAsim simulations also suggest that the magnitudes of beam and halo neutral densities are relatively sensitive to the choice of the atomic physics databases.

  2. On generating counter-rotating streamwise vortices

    KAUST Repository

    Winoto, S H

    2015-09-23

    Counter-rotating streamwise vortices are known to enhance the heat transfer rate from a surface and also to improve the aerodynamic performance of an aerofoil. In this paper, some methods to generate such counter-rotating vortices using different methods or physical conditions will be briefly considered and discussed.

  3. Counter-Propagating Coherent Stimulated Raman Spectroscopy for Remote Sensing in Air

    Science.gov (United States)

    Yuan, Luqi; Traverso, Andrew; Voronine, Dmitri; Jha, Pankaj; Wang, Kai; Sokolov, Alexei; Scully, Marlan

    2011-03-01

    We analyze phase-matching conditions in various four-wave mixing schemes for coherent nonlinear optical spectroscopy in the counter-propagating beam configuration. Coherent stimulated Raman spectroscopy satisfies the conditions and gives a signal containing specific molecular spectroscopic information. A counter-propagating broadband and a narrowband pulses are used to measure the Raman spectrum with a single shot. In addition, the nonresonant background due to the nondegenerate four-wave mixing is suppressed. Using this technique we develop a new scheme for standoff spectroscopy in atmosphere by using nitrogen molecules in air as a gain medium for remote lasing.

  4. Counter traction makes endoscopic submucosal dissection easier.

    Science.gov (United States)

    Oyama, Tsuneo

    2012-11-01

    Poor counter traction and poor field of vision make endoscopic submucosal dissection (ESD) difficult. Good counter traction allows dissections to be performed more quickly and safely. Position change, which utilizes gravity, is the simplest method to create a clear field of vision. It is useful especially for esophageal and colon ESD. The second easiest method is clip with line method. Counter traction made by clip with line accomplishes the creation of a clear field of vision and suitable counter traction thereby making ESD more efficient and safe. The author published this method in 2002. The name ESD was not established in those days; the name cutting endoscopic mucosal resection (EMR) or EMR with hook knife was used. The other traction methods such as external grasping forceps, internal traction, double channel scope, and double scopes method are introduced in this paper. A good strategy for creating counter traction makes ESD easier.

  5. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    Science.gov (United States)

    Bonomo, F.; Ruf, B.; Barbisan, M.; Cristofaro, S.; Schiesko, L.; Fantz, U.; Franzen, P.; Pasqualotto, R.; Riedl, R.; Serianni, G.; Wünderlich, D.

    2015-04-01

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the Hα light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of Hα spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  6. The Omega Counter, a Frequency Counter Based on the Linear Regression

    CERN Document Server

    Rubiola, E; Bourgeois, P -Y; Vernotte, F

    2015-01-01

    This article introduces the {\\Omega} counter, a frequency counter -- or a frequency-to-digital converter, in a different jargon -- based on the Linear Regression (LR) algorithm on time stamps. We discuss the noise of the electronics. We derive the statistical properties of the {\\Omega} counter on rigorous mathematical basis, including the weighted measure and the frequency response. We describe an implementation based on a SoC, under test in our laboratory, and we compare the {\\Omega} counter to the traditional {\\Pi} and {\\Lambda} counters. The LR exhibits optimum rejection of white phase noise, superior to that of the {\\Pi} and {\\Lambda} counters. White noise is the major practical problem of wideband digital electronics, both in the instrument internal circuits and in the fast processes which we may want to measure. The {\\Omega} counter finds a natural application in the measurement of the Parabolic Variance, described in the companion article arXiv:1506.00687 [physics.data-an].

  7. An array of low-background 3He proportional counters for the Sudbury Neutrino Observatory

    Science.gov (United States)

    Amsbaugh, J. F.; Anaya, J. M.; Banar, J.; Bowles, T. J.; Browne, M. C.; Bullard, T. V.; Burritt, T. H.; Cox-Mobrand, G. A.; Dai, X.; Deng, H.; Di Marco, M.; Doe, P. J.; Dragowsky, M. R.; Duba, C. A.; Duncan, F. A.; Earle, E. D.; Elliott, S. R.; Esch, E.-I.; Fergani, H.; Formaggio, J. A.; Fowler, M. M.; Franklin, J. E.; Geissbühler, P.; Germani, J. V.; Goldschmidt, A.; Guillian, E.; Hallin, A. L.; Harper, G.; Harvey, P. J.; Hazama, R.; Heeger, K. M.; Heise, J.; Hime, A.; Howe, M. A.; Huang, M.; Kormos, L. L.; Kraus, C.; Krauss, C. B.; Law, J.; Lawson, I. T.; Lesko, K. T.; Loach, J. C.; Majerus, S.; Manor, J.; McGee, S.; Miknaitis, K. K. S.; Miller, G. G.; Morissette, B.; Myers, A.; Oblath, N. S.; O'Keeffe, H. M.; Ollerhead, R. W.; Peeters, S. J. M.; Poon, A. W. P.; Prior, G.; Reitzner, S. D.; Rielage, K.; Robertson, R. G. H.; Skensved, P.; Smith, A. R.; Smith, M. W. E.; Steiger, T. D.; Stonehill, L. C.; Thornewell, P. M.; Tolich, N.; VanDevender, B. A.; Van Wechel, T. D.; Wall, B. L.; Wan Chan Tseung, H.; Wendland, J.; West, N.; Wilhelmy, J. B.; Wilkerson, J. F.; Wouters, J. M.

    2007-09-01

    An array of Neutral-Current Detectors (NCDs) has been built in order to make a unique measurement of the total active flux of solar neutrinos in the Sudbury Neutrino Observatory (SNO). Data in the third phase of the SNO experiment were collected between November 2004 and 2006, after the NCD array was added to improve the neutral-current sensitivity of the SNO detector. This array consisted of 36 strings of proportional counters filled with a mixture of 3He and CF 4 gas capable of detecting the neutrons liberated by the neutrino-deuteron neutral-current reaction in the D 2O, and four strings filled with a mixture of 4He and CF 4 gas for background measurements. The proportional counter diameter is 5 cm. The total deployed array length was 398 m. The SNO NCD array is the lowest-radioactivity large array of proportional counters ever produced. This article describes the design, construction, deployment, and characterization of the NCD array, discusses the electronics and data acquisition system, and considers event signatures and backgrounds.

  8. An array of low-background $^3$He proportional counters for the Sudbury Neutrino Observatory

    CERN Document Server

    Amsbaugh, J F; Banar, J C; Bowles, T J; Browne, M C; Bullard, T V; Burritt, T H; Cox-Mobrand, G A; Dai, X; Deng, H; Di Marco, M; Doe, P J; Dragowsky, M R; Duba, C A; Duncan, F A; Earle, E D; Elliott, S R; Esch, E -I; Fergani, H; Formaggio, J A; Fowler, M M; Franklin, J E; Geissbühler, P; Germani, J V; Goldschmidt, A; Guillian, E; Hallin, A L; Harper, G; Harvey, P J; Hazama, R; Heeger, K M; Heise, J; Hime, A; Howe, M A; Huang, M; Kormos, L L; Kraus, C V; Krauss, C B; Law, J; Lawson, I T; Lesko, K T; Loach, J C; Majerus, S; Manor, J; McGee, S; Miknaitis, K K S; Miller, G G; Morissette, B; Myers, A; Oblath, N S; O'Keeffe, H M; Ollerhead, R W; Peeters, S J M; Poon, A W P; Prior, G; Reitzner, S D; Rielage, K; Robertson, R G H; Skensved, P; Smith, A R; Smith, M W E; Steiger, T D; Stonehill, L C; Thornewell, P M; Tolich, N; VanDevender, B A; Van Wechel, T D; Wall, B L; Tseung, H Wan Chan; Wendland, J; West, N; Wilhelmy, J B; Wilkerson, J F; Wouters, J M

    2007-01-01

    An array of Neutral-Current Detectors (NCDs) has been built in order to make a unique measurement of the total active flux of solar neutrinos in the Sudbury Neutrino Observatory (SNO). Data in the third phase of the SNO experiment were collected between November 2004 and November 2006, after the NCD array was added to improve the neutral-current sensitivity of the SNO detector. This array consisted of 36 strings of proportional counters filled with a mixture of $^3$He and CF$_4$ gas capable of detecting the neutrons liberated by the neutrino-deuteron neutral current reaction in the D$_2$O, and four strings filled with a mixture of $^4$He and CF$_4$ gas for background measurements. The proportional counter diameter is 5 cm. The total deployed array length was 398 m. The SNO NCD array is the lowest-radioactivity large array of proportional counters ever produced. This article describes the design, construction, deployment, and characterization of the NCD array, discusses the electronics and data acquisition sys...

  9. Magnetic configuration effects on plasma transport under Neutral Beam Injection at TJ-II (Simulation); Efectos de Configuracion Magnetica en el Transporte de Plasma durante la Inyeccion de Haces Neutros en el TJ-II (Simulacion)

    Energy Technology Data Exchange (ETDEWEB)

    Guasp, J.; Fuentes, C.; Liniers, M.

    2001-07-01

    A systematic analysis of magnetic configurations (27 in total), using a Transport model including impurity dynamics and sputtering effects has been done. For small size configurations or those close to rational t values there is radioactive collapse, independently of the external gas puffing (GP) strategy chosen. The reason is the insufficiency of observed power, either by the high shine through losses due to their low radii, or by the increase of fast ion orbit losses near the resonances. For the majority of configurations without collapse, fast ion orbit losses for CO injection (going in the same direction than the toroidal magnetic field) are higher, and in consequence the power absorption and the plasma {beta} achieved are laser, than for the opposite direction. Nevertheless in the region placed just above the main resonances (1/3 and 1/2 per period) this situation reverses. The reasons have been analysed and explained at previous studies. A consequence of this fact is that the optima of confinement for the Counter case are shifted towards higher t values than the CO one, with higher plasma {beta}, except near the resonances. As usual the balanced case is in between. The optima achieving stationary state are very close (and often are coincident) with those lacking that restriction. The best configuration (highest average {beta}) for balanced injection, with <{beta}>=1.1% and central value 3.2%, although in this region the results are rather insensitive to configuration and GP strategy. The configurations placed around the 100{sub 4}4 would need also the lowest power entering the torus in order to avoid collapse and to achieve an acceptable NBI absorption level. (Author) 12 refs.

  10. Determination of the LEP beam energy through {zeta}{gamma} events and the measurements of 3 neutral gauge bosons in the ALEPH experiment; Determination de l'energie du faisceau du LEP a l'aide des evenements {zeta}{gamma} et mesures de couplages a trois bosons de jauge neutres dans l'experience ALEPH

    Energy Technology Data Exchange (ETDEWEB)

    Trocme, B

    2001-04-01

    After six years of data taking at Z peak, LEP beam energy continuously raised to finally reach 104.5 GeV, allowing notably W pairs production. Z resonance remains however important trough radiative return process; a hard photon being emitted in initial state, the centre of mass energy is reduced to an effective value close to Z mass. These events taken by Aleph experiment between 1998 and 2000 have been analysed following two distinct approaches, that are detailed in this thesis. With nearly 700 pb{sup -1} taken by each experiment, it is obvious that final W mass measurement- one major goal of LEP2 program- will be dominated by systematic error, with a large contribution from the uncertainty on the LEP beam energy. A fit of the radiative return peak position allows an original determination of the latter. Being not only a single measurement, this method is also a powerful tool to check techniques used in W mass measurement. Moreover, Z{gamma} events final states are similar to processes with a vertex involving three neutral gauge bosons. Anomalous production cross section, as well as deformed kinematic distributions, can be a probe of new physic that lies at much higher energy scales. A search for such phenomena has also been performed. (author)

  11. Hierarchical steepness, counter-aggression, and macaque social style scale.

    Science.gov (United States)

    Balasubramaniam, Krishna N; Dittmar, Katharina; Berman, Carol M; Butovskaya, Marina; Cooper, Mathew A; Majolo, Bonaventura; Ogawa, Hideshi; Schino, Gabriele; Thierry, Bernard; De Waal, Frans B M

    2012-10-01

    Nonhuman primates show remarkable variation in several aspects of social structure. One way to characterize this variation in the genus Macaca is through the concept of social style, which is based on the observation that several social traits appear to covary with one another in a linear or at least continuous manner. In practice, macaques are more simply characterized as fitting a four-grade scale in which species range from extremely despotic (grade 1) to extremely tolerant (grade 4). Here, we examine the fit of three core measures of social style-two measures of dominance gradients (hierarchical steepness) and another closely related measure (counter-aggression)-to this scale, controlling for phylogenetic relationships. Although raw scores for both steepness and counter-aggression correlated with social scale in predicted directions, the distributions appeared to vary by measure. Counter-aggression appeared to vary dichotomously with scale, with grade 4 species being distinct from all other grades. Steepness measures appeared more continuous. Species in grades 1 and 4 were distinct from one another on all measures, but those in the intermediate grades varied inconsistently. This confirms previous indications that covariation is more readily observable when comparing species at the extreme ends of the scale than those in intermediate positions. When behavioral measures were mapped onto phylogenetic trees, independent contrasts showed no significant consistent directional changes at nodes below which there were evolutionary changes in scale. Further, contrasts were no greater at these nodes than at neutral nodes. This suggests that correlations with the scale can be attributed largely to species' phylogenetic relationships. This could be due in turn to a structural linkage of social traits based on adaptation to similar ecological conditions in the distant past, or simply to unlinked phylogenetic closeness.

  12. A superconducting NbN detector for neutral nanoparticles

    CERN Document Server

    Marksteiner, M; Sclafani, M; Haslinger, P; Ulbricht, H; Korneev, A; Semenov, A; Goltsman, G; Arndt, M

    2014-01-01

    We present a proof-of-principle study of superconducting single photon detectors (SSPD) for the detection of individual neutral molecules/nanoparticles at low energies. The new detector is applied to characterize a laser desorption source for biomolecules and it allows to retrieve the arrival time distribution of a pulsed molecular beam containing the amino acid tryptophan, the polypeptide gramicidin as well as insulin, myoglobin and hemoglobin. We discuss the experimental evidence that the detector is actually sensitive to isolated neutral particles.

  13. Plasma-beam traps and radiofrequency quadrupole beam coolers.

    Science.gov (United States)

    Maggiore, M; Cavenago, M; Comunian, M; Chirulotto, F; Galatà, A; De Lazzari, M; Porcellato, A M; Roncolato, C; Stark, S; Caruso, A; Longhitano, A; Cavaliere, F; Maero, G; Paroli, B; Pozzoli, R; Romé, M

    2014-02-01

    Two linear trap devices for particle beam manipulation (including emittance reduction, cooling, control of instabilities, dust dynamics, and non-neutral plasmas) are here presented, namely, a radiofrequency quadrupole (RFQ) beam cooler and a compact Penning trap with a dust injector. Both beam dynamics studies by means of dedicated codes including the interaction of the ions with a buffer gas (up to 3 Pa pressure), and the electromagnetic design of the RFQ beam cooler are reported. The compact multipurpose Penning trap is aimed to the study of multispecies charged particle samples, primarily electron beams interacting with a background gas and/or a micrometric dust contaminant. Using a 0.9 T solenoid and an electrode stack where both static and RF electric fields can be applied, both beam transport and confinement operations will be available. The design of the apparatus is presented.

  14. Getting ready for SPS beam

    CERN Multimedia

    1977-01-01

    View from downstream of the WA7 experiment along beam H1B. In the foreground are scintillator hodoscopes and immediately behind them, is a threshold Cerenkov counter, standing on its edge. The WA7 control hut is located on the right, over the concrete shielding blocks. Still more right, the other branch of the H1 beam, E1A/H1A, runs towards the Omega Facility. WA7 by the CERN-Genoa-LAPP, Annecy-Niels Bohr Institute, Copenhagen-Oslo, University College, London Collaboration was meant to study two-body reactions at large transverse momentum.

  15. Instability of counter-rotating stellar disks

    Science.gov (United States)

    Hohlfeld, R. G.; Lovelace, R. V. E.

    2015-09-01

    We use an N-body simulation, constructed using GADGET-2, to investigate an accretion flow onto an astrophysical disk that is in the opposite sense to the disk's rotation. In order to separate dynamics intrinsic to the counter-rotating flow from the impact of the flow onto the disk, we consider an initial condition in which the counter-rotating flow is in an annular region immediately exterior the main portion of the astrophysical disk. Such counter-rotating flows are seen in systems such as NGC 4826 (known as the "Evil Eye Galaxy"). Interaction between the rotating and counter-rotating components is due to two-stream instability in the boundary region. A multi-armed spiral density wave is excited in the astrophysical disk and a density distribution with high azimuthal mode number is excited in the counter-rotating flow. Density fluctuations in the counter-rotating flow aggregate into larger clumps and some of the material in the counter-rotating flow is scattered to large radii. Accretion flow processes such as this are increasingly seen to be of importance in the evolution of multi-component galactic disks.

  16. 21 CFR 866.2170 - Automated colony counter.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2170 Automated colony counter. (a) Identification. An automated colony counter is a mechanical device intended for...

  17. Squid based beam current meter

    Energy Technology Data Exchange (ETDEWEB)

    Kuchnir, M.

    1983-11-25

    A SQUID based beam current meter has the capability of measuring the current of a beam with as little as 30 x 155 antiprotons (with a signal to noise ratio of 2). If low noise dc current is used to cancel most of the beam or an up-down counter is used to count auto-resets this sensitivity will be available at any time in the acumulation process. This current meter will therefore be a unique diagnostic tool for optimizing the performance of several Tev I components. Besides requiring liquid helium it seems that its only drawback is not to follow with the above sensitivity a sudden beam change larger than 16 ..mu..A, something that could be done using a second one in a less sensitive configuration.

  18. Silica aerogel threshold Cherenkov counters for the JLab Hall A spectrometers: improvements and proposed modifications

    CERN Document Server

    Lagamba, L; Colilli, S; Crateri, R; De Leo, R; Frullani, S; Garibaldi, F; Giuliani, F; Gricia, M; Iodice, M; Iommi, R; Leone, A; Lucentini, M; Mostarda, A; Nappi, E; Perrino, R; Pierangeli, L; Santavenere, F; Urciuoli, G M

    2001-01-01

    Recently approved experiments at Jefferson Lab Hall A require a clean kaon identification in a large electron, pion, and proton background environment. To this end, improved performance is required of the silica aerogel threshold Cherenkov counters installed in the focal plane of the two Hall A spectrometers. In this paper we propose two strategies to improve the performance of the Cherenkov counters which presently use a hydrophilic aerogel radiator, and convey Cherenkov photons towards the photomultipliers by means of mirrors with a parabolic shape in one direction and flat in the other. The first strategy is aerogel baking. In the second strategy we propose a modification of the counter geometry by replacing the mirrors with a planar diffusing surface and by displacing in a different way the photomultipliers. Tests at CERN with a 5 GeV/c multiparticle beam revealed that both the strategies are able to increase significantly the number of the detected Cherenkov photons and, therefore, the detector performan...

  19. The V0 detector is two disks of counters in both sides of the interaction point.

    CERN Multimedia

    Grossiord, Jean-Yves

    2006-01-01

    The V0 detector is two disks of counters in both sides of the interaction point. Here is the V0C disk to be fixed on the front face of the muon spectrometer absorber. It is made of 48 scintillating elements coupled to two wavelength fibre layers which emit and guide the light up to connrctors arounda case made of Carbon fibre plates. The light going out of connectors is collected by an optical fibre bundle and transmitted at 3 metres to photo-multipliers which convert light to electrical signal. The elements are set in the case following 2 small rings of 8 counters and 2 large rings of 16 counters grouped two by two. 32 channels of detection distributed around the LHC beam pipe constitute thus the detector

  20. Taming Past LTL and Flat Counter Systems

    CERN Document Server

    Demri, Stéphane; sangnier, Arnaud

    2012-01-01

    Reachability and LTL model-checking problems for flat counter systems are known to be decidable but whereas the reachability problem can be shown in NP, the best known complexity upper bound for the latter problem is made of a tower of several exponentials. Herein, we show that the problem is only NP-complete even if LTL admits past-time operators and arithmetical constraints on counters. Actually, the NP upper bound is shown by adequately combining a new stuttering theorem for Past LTL and the property of small integer solutions for quantifier-free Presburger formulae. Other complexity results are proved, for instance for restricted classes of flat counter systems.

  1. GEIGER-MULLER TYPE COUNTER TUBE

    Science.gov (United States)

    Fowler, I.L.; Watt, L.A.K.

    1959-12-15

    A single counter tube capable of responding to a wide range of intensities is described. The counter tube comprises a tubular cathode and an anode extending centrally of the cathode. The spacing between the outer surface of the anode and the inner surface of the cathode is varied along the length of the tube to provide different counting volumes in adjacent portions of the tube. A large counting volume in one portion adjacent to a low-energy absorption window gives adequate sensitivity for measuring lowintensity radiation, while a smaller volume with close electrode spacing is provided in the counter to make possible measurement of intense garnma radiation fields.

  2. Time interleaved counter analog to digital converters

    OpenAIRE

    Danesh, Seyed Amir Ali

    2011-01-01

    The work explores extending time interleaving in A/D converters, by applying a high-level of parallelism to one of the slowest and simplest types of data-converters, the counter ADC. The motivation for the work is to realise high-performance re-configurable A/D converters for use in multi-standard and multi-PHY communication receivers with signal bandwidths in the 10s to 100s of MHz. The counter ADC requires only a comparator, a ramp signal, and a digital counter, where the ...

  3. Spinning of a submicron sphere by Airy beams.

    Science.gov (United States)

    Kim, Kyoung-Youm; Kim, Saehwa

    2016-01-01

    We show that by employing two incoherent counter-propagating Airy beams, we can manipulate a submicron sphere to spin around a transverse axis. We can control not only the spinning speed, but also the direction of the spinning axis by changing the polarization directions of Airy beams.

  4. Ion charge neutralization effects in scanning electron microscopes.

    Science.gov (United States)

    Crawford, C K

    1980-01-01

    The use of low energy ion charge neutralization to stabilize surface potentials in scanning microscopes leads to the observation of new effects. Among the most important of these, are effects which result from the primary beam being scanned in a raster. A new theory which describes raster charge-up for highly insulating specimens is presented. It is shown that the required neutralizing ion current is a surprisingly strong function of the primary electron current, the raster parameters, specimen parameters, and magnification. Contrary to intuition, the required ion current is not linearly related to the primary electron current. Methods of adjusting parameters to achieve better ion charge neutralization are discussed.

  5. Permanent traffic counters maintained by the NMDOT

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — A point dataset representing the permanent traffic counters maintained by the NMDOT. Event mapped dataset by LRS info provided by Traffic group.

  6. Particle identification performance of the prototype Aerogel RICH counter for the Belle II experiment

    CERN Document Server

    Iwata, S; Hara, K; Iijima, T; Ikeda, H; Kakuno, H; Kawai, H; Kawasaki, T; Korpar, S; Krizan, P; Kumita, T; Nishida, S; Ogawa, S; Pestotnik, R; Šantelj, L; Seljak, A; Tabata, M; Tahirović, E; Yusa, Y

    2016-01-01

    We have developed a new type of particle identification device, called an Aerogel Ring Imaging Cherenkov (ARICH) counter, for the Belle II experiment. It uses silica aerogel tiles as Cherenkov radiators. For detection of Cherenkov photons, Hybrid Avalanche Photo-Detectors (HAPDs) are used. The designed HAPD has a high sensitivity to single photons under a strong magnetic field. We have confirmed that the HAPD provides high efficiency for single-photon detection even after exposure to neutron and gamma-ray radiation that exceeds the levels expected in the 10-year Belle II operation. In order to confirm the basic performance of the ARICH counter system, we carried out a beam test at the DESY using a prototype of the ARICH counter with six HAPD modules. The results are in agreement with our expectations and confirm the suitability of the ARICH counter for the Belle II experiment. Based on the in-beam performance of the device, we expect that the identification efficiency at 3.5 GeV/c is 97.4% and 4.9% for pions ...

  7. Development of a Mobile Ice Nucleus Counter

    Energy Technology Data Exchange (ETDEWEB)

    Kok, Gregory [Droplet Measurement Technologies, Boulder, CO (United States); Kulkarni, Gourihar [Droplet Measurement Technologies, Boulder, CO (United States)

    2014-07-10

    An ice nucleus counter has been constructed. The instrument uses built-in refrigeration systems for wall cooling. A cascade refrigeration system will allow the cold wall to operate as low as -70°C, and a single stage system can operate the warm wall at -45C. A unique optical particle counter has been constructed using polarization detection of the scattered light. This allows differentiation of the particles exiting the chamber to determine if they are ice or liquid.

  8. Development of a Mobile Ice Nucleus Counter

    Energy Technology Data Exchange (ETDEWEB)

    Kok, Gregory; Kulkarni, Gourihar

    2014-07-10

    An ice nucleus counter has been constructed. The instrument uses built-in refrigeration systems for wall cooling. A cascade refrigeration system will allow the cold wall to operate as low as -70 deg C, and a single stage system can operate the warm wall at -45 deg C. A unique optical particle counter has been constructed using polarization detection of the scattered light. This allows differentiation of the particles exiting the chamber to determine if they are ice or liquid.

  9. Lifetime characteristics of Gaiger-Muller counters

    Directory of Open Access Journals (Sweden)

    Kartalović Nenad M.

    2016-01-01

    Full Text Available This paper discusses the process of functional aging of Geiger-Muller counters. Two types of Geiger-Muller counter chambers were characterized in an experiment using a combined constant voltage. Chamber A had a coaxial geometry and chamber B had a plan-parallel geometry. The experimental results indicate that the aging process was faster in the case of chambers with a coaxial geometry. The results are explained based on the process of electrical discharges in gasses.

  10. Novel Designs of Quantum Reversible Counters

    Science.gov (United States)

    Qi, Xuemei; Zhu, Haihong; Chen, Fulong; Zhu, Junru; Zhang, Ziyang

    2016-11-01

    Reversible logic, as an interesting and important issue, has been widely used in designing combinational and sequential circuits for low-power and high-speed computation. Though a significant number of works have been done on reversible combinational logic, the realization of reversible sequential circuit is still at premature stage. Reversible counter is not only an important part of the sequential circuit but also an essential part of the quantum circuit system. In this paper, we designed two kinds of novel reversible counters. In order to construct counter, the innovative reversible T Flip-flop Gate (TFG), T Flip-flop block (T_FF) and JK flip-flop block (JK_FF) are proposed. Based on the above blocks and some existing reversible gates, the 4-bit binary-coded decimal (BCD) counter and controlled Up/Down synchronous counter are designed. With the help of Verilog hardware description language (Verilog HDL), these counters above have been modeled and confirmed. According to the simulation results, our circuits' logic structures are validated. Compared to the existing ones in terms of quantum cost (QC), delay (DL) and garbage outputs (GBO), it can be concluded that our designs perform better than the others. There is no doubt that they can be used as a kind of important storage components to be applied in future low-power computing systems.

  11. Chemical reaction dynamics of Rydberg atoms with neutral molecules: a comparison of molecular-beam and classical trajectory results for the H(n)+D2-->HD+D(n') reaction.

    Science.gov (United States)

    Song, Hui; Dai, Dongxu; Wu, Guorong; Wang, Chia Chen; Harich, Steven A; Hayes, Michael Y; Wang, Xiuyan; Gerlich, Dieter; Yang, Xueming; Skodje, Rex T

    2005-08-15

    Recent molecular-beam experiments have probed the dynamics of the Rydberg-atom reaction, H(n)+D2-->HD+D(n) at low collision energies. It was discovered that the rotationally resolved product distribution was remarkably similar to a much more limited data set obtained at a single scattering angle for the ion-molecule reaction H++D2-->D++HD. The equivalence of these two problems would be consistent with the Fermi-independent-collider model (electron acting as a spectator) and would provide an important new avenue for the study of ion-molecule reactions. In this work, we employ a classical trajectory calculation on the ion-molecule reaction to facilitate a more extensive comparison between the two systems. The trajectory simulations tend to confirm the equivalence of the ion+molecule dynamics to that for the Rydberg-atom+molecule system. The theory reproduces the close relationship of the two experimental observations made previously. However, some differences between the Rydberg-atom experiments and the trajectory simulations are seen when comparisons are made to a broader data set. In particular, the angular distribution of the differential cross section exhibits more asymmetry in the experiment than in the theory. The potential breakdown of the classical model is discussed. The role of the "spectator" Rydberg electron is addressed and several crucial issues for future theoretical work are brought out.

  12. Bleach Neutralizes Mold Allergens

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    Researchers at National Jewish Medical and Research Center have demonstrated that dilute bleach not only kills common household mold, but may also neutralize the mold allergens that cause most mold-related health complaints. The study, published in the Journal of Allergy and Clinical Immunology, is the first to test the effect on allergic…

  13. CO2-Neutral Fuels

    NARCIS (Netherlands)

    Goede, A.; van de Sanden, M. C. M.

    2016-01-01

    Mimicking the biogeochemical cycle of System Earth, synthetic hydrocarbon fuels are produced from recycled CO2 and H2O powered by renewable energy. Recapturing CO2 after use closes the carbon cycle, rendering the fuel cycle CO2 neutral. Non-equilibrium molecular CO2 vibrations are key to high energy

  14. CO2-Neutral Fuels

    Science.gov (United States)

    Goede, Adelbert; van de Sanden, Richard

    2016-06-01

    Mimicking the biogeochemical cycle of System Earth, synthetic hydrocarbon fuels are produced from recycled CO2 and H2O powered by renewable energy. Recapturing CO2 after use closes the carbon cycle, rendering the fuel cycle CO2 neutral. Non-equilibrium molecular CO2 vibrations are key to high energy efficiency.

  15. CO2-Neutral Fuels

    NARCIS (Netherlands)

    Goede, A.; van de Sanden, M. C. M.

    2016-01-01

    Mimicking the biogeochemical cycle of System Earth, synthetic hydrocarbon fuels are produced from recycled CO2 and H2O powered by renewable energy. Recapturing CO2 after use closes the carbon cycle, rendering the fuel cycle CO2 neutral. Non-equilibrium molecular CO2 vibrations are key to high energy

  16. Control Modules for Scintillation Counters in the SPS Experimental Areas

    CERN Document Server

    Baribaud, Guy; Cojan, A; Ferri, G; Fullerton, J; Manarin, A; Spanggaard, J

    2001-01-01

    The hardware used in the SPS Experimental Areas to control the beam instrumentation electronics and mechanics of the particle detectors is based on CAMAC and NIM modules. The maintenance of this hardware now presents very serious problems. The modules used to operate the Experimental Areas are numerous and older than 20 years so many of them cannot be repaired any more and CAMAC is no longer well supported by industry. The fast evolution of technology and a better understanding of the detectors allow a new equipment-oriented approach, which is more favourable for maintenance purposes and presents fewer data handling problems. VME and IP Modules were selected as standard components to implement the new electronics to control and read out the particle detectors. The first application implemented in this way concerns the instrumentation for the Scintillation Counters (formerly referred to as triggers). The fundamental options and the design features will be presented.

  17. Nuclear counter effect and pi-e misidentification

    CERN Document Server

    Zürcher, D

    2000-01-01

    The e sup+-/pi sup+- discrimination within the CMS(1) ECAL is investigated using GEANT simulations and the 1998 test beam results. If one takes into account the energy left in the ECAL crystals alone (i.e. without read-out effects), the probability that a pi sup+- leaves more than 95% of its initial energy decreases from about 0.01% for 10 GeV to about 0.001% for 50 GeV. The Nuclear Counter Effect within the Avalanche Photo-Diodes (APD) enhances the probability of an electron misidentification. With the expected value of this effect (approx 100 MeV), this probability appears then to be between 0.2% and 0.01% for initial momenta varying, respectively, between 5 and 50 GeV. Important consequences of the pion-electron misidentification could appear in the form of new possible backgrounds for physics channels.

  18. Waves in relativistic electron beam in low-density plasma

    Science.gov (United States)

    Sheinman, I.; Sheinman (Chernenco, J.

    2016-11-01

    Waves in electron beam in low-density plasma are analyzed. The analysis is based on complete electrodynamics consideration. Dependencies of dispersion laws from system parameters are investigated. It is shown that when relativistic electron beam is passed through low-density plasma surface waves of two types may exist. The first type is a high frequency wave on a boundary between the beam and neutralization area and the second type wave is on the boundary between neutralization area and stationary plasma.

  19. Beam simulation studies of ECR beam extraction and low energy beam transport for FRIB.

    Science.gov (United States)

    Ren, Haitao; Pozdeyev, Eduard; Lund, Steven M; Machicoane, Guillaume; Wu, Xiaoyu; Morgan, Glenn

    2016-02-01

    To meet the beam power requirements of 400 kW at the fragmentation target for facility for Rare Isotope Beams (FRIB), simultaneous acceleration of two-charge states should be used for heavier ions. These intense multi-charged ion beams will be produced by a 28 GHz electron cyclotron resonance (ECR) ion source at a high voltage of 35 kV. After extraction, the ion beam will be pre-accelerated to 12 keV/u with a 50 kV platform, transported down to an achromatic charge state selection (CSS) system followed by a vertical transport line, and then injected into a radio frequency quadrupole accelerator. The TRACK code developed at ANL is used to perform the simulations of the ECR beam extraction and low energy beam transport for FRIB. In this study, we include the magnetic field of ECR ion source into simulations. Different initial beam conditions as well as different space charge neutralization levels are tested for the ECR beamline. The beam loss in CSS system and the corresponding protective measures are discussed. The detailed results about the beam dynamic simulation and beam loss in CSS system will be presented in this paper.

  20. Evidence for the Production of Neutral Mesons by Photons

    Science.gov (United States)

    Steinberger, J.; Panofsky, W. K. H.; Steller, J.

    1950-04-01

    Evidence in favor of the existence of a gamma unstable neutral meson; report on the detection of the coincidences between the two gamma rays produced by the bombardment of various nuclei in the x-ray beam of the Berkeley synchrotron.

  1. Beam ion confinement on NSTX-U

    Science.gov (United States)

    Liu, D.; Heidbrink, W. W.; Hao, G. Z.; Podesta, M.; Darrow, D. S.; Fredrickson, E. D.

    2016-10-01

    A second and more tangential neutral beam line is a major upgrade component of the National Spherical Torus Experiment - Upgrade (NSTX-U) with the purpose of improving neutral beam current drive efficiency and providing more flexibility in current/pressure profile control. Good beam ion confinement is essential to achieve the anticipated improvements in performance. In the planned beam ion confinement experiment, various short and long (relative to fast ion slowing-down time) neutral beam (NB) pulses from six neutral beam sources will be injected into center-stack limited L-mode plasmas to characterize the beam ion confinement and distribution function produced by the new and the existing NBI lines. The neutron rate decay after the turn-off of short NB pulses will be used to estimate the beam ion confinement time and to investigate its dependence on NB source/geometry, injection energy, and plasma current. The tangential and vertical Fast-Ion D-Alpha (FIDA) diagnostics and multi-view Solid State Neutral Particle Analyzer (SSNPA) arrays will be used to measure beam ion slowing-down distribution function and spatial profile during the injection of relatively long NB pulses. Beam ion prompt losses will be monitored with a scintillator Fast Lost Ion Probe (sFLIP) diagnostic. The experimental data and comparisons with classical predictions from NUBEAM modeling will be presented. Work supported by U.S. DOE DE-AC0209CH11466, DE-FG02-06ER54867, and DE-FG03-02ER54681.

  2. Ultracold Neutral Plasmas

    CERN Document Server

    Killian, T C; Gupta, P; Laha, S; Martinez, Y N; Mickelson, P G; Nagel, S B; Saenz, A D; Simien, C E; Killian, Thomas C.

    2005-01-01

    Ultracold neutral plasmas are formed by photoionizing laser-cooled atoms near the ionization threshold. Through the application of atomic physics techniques and diagnostics, these experiments stretch the boundaries of traditional neutral plasma physics. The electron temperature in these plasmas ranges from 1-1000 K and the ion temperature is around 1 K. The density can approach $10^{11}$ cm$^{-3}$. Fundamental interest stems from the possibility of creating strongly-coupled plasmas, but recombination, collective modes, and thermalization in these systems have also been studied. Optical absorption images of a strontium plasma, using the Sr$^+$ ${^2S_{1/2}} -> {^2P_{1/2}}$ transition at 422 nm, depict the density profile of the plasma, and probe kinetics on a 50 ns time-scale. The Doppler-broadened ion absorption spectrum measures the ion velocity distribution, which gives an accurate measure of the ion dynamics in the first microsecond after photoionization.

  3. Between detection and neutralization.

    Energy Technology Data Exchange (ETDEWEB)

    Snell, Mark Kamerer; Green, Mary Wilson; Adams, Douglas Glenn; Pritchard, Daniel Allison

    2005-08-01

    Security system analytical performance analysis is generally based on the probability of system effectiveness. The probability of effectiveness is a function of the probabilities of interruption and neutralization. Interruption occurs if the response forces are notified in sufficient time to engage the adversary. Neutralization occurs if the adversary attack is defeated after the security forces have actively engaged the adversary. Both depend upon communications of data. This paper explores details of embedded communications functions that are often assumed to be inconsequential. It is the intent of the authors to bring focus to an issue in security system modeling that, if not well understood, has the potential to be a deciding factor in the overall system failure or effectiveness.

  4. Gargamelle: neutral current event

    CERN Multimedia

    1973-01-01

    This event shows real tracks of particles from the 1200 litre Gargamelle bubble chamber that ran on the PS from 1970 to 1976 and on the SPS from 1976 to 1979. In this image a neutrino passes close to a nucleon and reemerges as a neutrino. Such events are called neutral curent, as they are mediated by the Z0 boson which has no electric charge.

  5. Neutral atom traps.

    Energy Technology Data Exchange (ETDEWEB)

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  6. Detecting the Elusive Blazar Counter-Jets

    CERN Document Server

    Liodakis, I; Angelakis, E

    2016-01-01

    Detection of blazar pc scale counter-jets is difficult, but it can provide invaluable insight into the relativistic effects, radiative processes and the complex mechanisms of jet production, collimation and accelation in blazars. We build on recent populations models (optimized using the MOJAVE apparent velocity and redshift distributions) in order to derive the distribution of jet-to-counter-jet ratios and the flux densities of the counter-jet at different frequencies, in an effort to set minimum sensitivity limits required for existing and future telescope arrays in order to detect these elusive counter-jets. We find that: for the BL Lacs $5\\%$ of their counter-jets have a flux-density higher than 100mJy, $15\\%$ are higher than 10 mJy, and $32\\%$ have higher flux-density than 1 mJy, whereas for the FSRQs $8\\%$ have a flux-density higher than 10mJy, $17\\%$ are higher than 1 mJy, and $32\\%$ are higher than 0.1 mJy (at 15 GHz). Future telescopes like the SKA and newly operating like e-MERLIN and JVLA may detec...

  7. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Bonomo, F., E-mail: federica.bonomo@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Istituto Gas Ionizzati - CNR, Corso Stati Uniti 4, 35127 Padova (Italy); Ruf, B.; Schiesko, L.; Fantz, U.; Franzen, P.; Riedl, R.; Wünderlich, D. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Barbisan, M.; Pasqualotto, R.; Serianni, G. [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Cristofaro, S. [Universitá degli Studi di Padova, Via 8 Febbraio 2, 35122 Padova (Italy)

    2015-04-08

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (< 0.4 °) together with a low source pressure (≤ 0.3 Pa) would permit to reduce the ion losses along the beamline, keeping the stripping particle losses below 30%. However, the attainment of such beam properties is not straightforward. At IPP, the negative ion source testbed BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the H{sub α} light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of H{sub α} spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  8. Study on space charge compensation in negative hydrogen ion beam

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-15

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H{sup +} beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H{sup −} beam from a 2.45 GHz microwave driven H{sup −} ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

  9. Study on space charge compensation in negative hydrogen ion beam.

    Science.gov (United States)

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

    2016-02-01

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H(+) beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H(-) beam from a 2.45 GHz microwave driven H(-) ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

  10. Fast ion beam-plasma interaction system.

    Science.gov (United States)

    Breun, R A; Ferron, J R

    1979-07-01

    A device has been constructed for the study of the interaction between a fast ion beam and a target plasma of separately controllable parameters. The beam of either hydrogen or helium ions has an energy of 1-4 keV and a total current of 0.5-2 A. The beam energy and beam current can be varied separately. The ion source plasma is created by a pulsed (0.2-10-ms pulse length) discharge in neutral gas at up to 3 x 10(-3) Torr. The neutrals are pulsed into the source chamber, allowing the neutral pressure in the target region to remain less than 5 x 10(-5) Torr at a 2-Hz repetition rate. The creation of the source plasma can be described by a simple set of equations which predict optimum source design parameters. The target plasma is also produced by a pulsed discharge. Between the target and source chambers the beam is neutralized by electrons drawn from a set of hot filaments. Currently under study is an unstable wave in a field-free plasma excited when the beam velocity is nearly equal to the target electron thermal velocity (v(beam) approximately 3.5 x 10(7) cm/s, Te = 0.5 eV).

  11. Neutron spectroscopy with the Spherical Proportional Counter

    CERN Document Server

    Bougamont, E; Derre, J; Galan, J; Gerbier, G; Giomataris, I; Gros, M; Katsioulas, I; Jourde, D; Magnier, P; Navick, X F; Papaevangelou, T; Savvidis, I; Tsiledakis, G

    2015-01-01

    A novel large volume spherical proportional counter, recently developed, is used for neutron measurements. Gas mixtures of $N_{2}$ with $C_{2}H_{6}$ and pure $N_{2}$ are studied for thermal and fast neutron detection, providing a new way for the neutron spectroscopy. The neutrons are detected via the ${}^{14}N(n, p)C^{14}$ and ${}^{14}N(n, \\alpha)B^{11}$ reactions. Here we provide studies of the optimum gas mixture, the gas pressure and the most appropriate high voltage supply on the sensor of the detector in order to achieve the maximum amplification and better resolution. The detector is tested for thermal and fast neutrons detection with a ${}^{252}Cf$ and a ${}^{241}Am-{}^{9}Be$ neutron source. The atmospheric neutrons are successfully measured from thermal up to several MeV, well separated from the cosmic ray background. A comparison of the spherical proportional counter with the current available neutron counters is also given.

  12. Analysis of Power Distribution on Beamline Components at Different Neutralization Efficiencies on NBI Test Stand

    Science.gov (United States)

    Li, Xiang; Xu, Yongjian; Yu, Ling; Chen, Yu; Hu, Chundong; Tao, Ling

    2016-12-01

    Neutral beam injection is recognized as one of the most effective means for plasma heating. According to the research plan of the EAST physics experiment, two sets of neutral beam injector (4-8 MW, 10-100 s) were built and operated in 2014. Neutralization efficiency is one of the important parameters for neutral beam. High neutralization efficiency can not only improve injection power at the same beam energy, but also decrease the power deposited on the heat-load components in the neutral beam injector (NBI). This research explores the power deposition distribution at different neutralization efficiencies on the beamline components of the NBI device. This work has great significance for guiding the operation of EAST-NBI, especially in long pulse and high power operation, which can reduce the risk of thermal damage of the beamline components and extend the working life of the NBI device. supported by the International Science and Technology Cooperation Program of China (No. 2014DFG61950), National Natural Science Foundation of China (No. 11405207) and the Foundation of ASIPP (No. DSJJ-15-GC03)

  13. Design of a multi beam klystron cavity from its single beam parameters

    Energy Technology Data Exchange (ETDEWEB)

    Kant, Deepender, E-mail: dkc@ceeri.ernet.in; Joshi, L. M. [CSIR-Central Electronics Engineering Research Institute, Pilani (India); Janyani, Vijay [Department of ECE, MNIT, Jaipur (India)

    2016-03-09

    The klystron is a well-known microwave amplifier which uses kinetic energy of an electron beam for amplification of the RF signal. There are some limitations of conventional single beam klystron such as high operating voltage, low efficiency and bulky size at higher power levels, which are very effectively handled in Multi Beam Klystron (MBK) that uses multiple low purveyance electron beams for RF interaction. Each beam propagates along its individual transit path through a resonant cavity structure. Multi-Beam klystron cavity design is a critical task due to asymmetric cavity structure and can be simulated by 3D code only. The present paper shall discuss the design of multi beam RF cavities for klystrons operating at 2856 MHz (S-band) and 5 GHz (C-band) respectively. The design approach uses some scaling laws for finding the electron beam parameters of the multi beam device from their single beam counter parts. The scaled beam parameters are then used for finding the design parameters of the multi beam cavities. Design of the desired multi beam cavity can be optimized through iterative simulations in CST Microwave Studio.

  14. Time resolution of time-of-flight detector based on multiple scintillation counters readout by SiPMs

    CERN Document Server

    Cattaneo, P W; Gatti, F; Nishimura, M; Ootani, W; Rossella, M; Shirabe, S; Uchiyama, Y

    2015-01-01

    A new timing detector measuring ~50 MeV/c positrons is under development for the MEG II experiment, aiming at a time resolution $\\sigma_t \\sim 30~\\mathrm{ps}$. The resolution is expected to be achieved by measuring each positron time with multiple counters made of plastic scintillator readout by silicon photomultipliers (SiPMs). The purpose of this work is to demonstrate the time resolution for ~50 MeV/c positrons using prototype counters. Counters with dimensions of $90\\times 40\\times 5~\\mathrm{mm}^3$ readout by three SiPMs at each end were build with SiPMs from Hamamatsu Photonics and AdvanSiD and tested in a positron beam at the DA$\\Phi$NE Beam Test Facility. It was found that the time resolution improves nearly as the square root of the number of counter hits. A time resolution $\\sigma_t=26.2\\pm1.3~\\mathrm{ps}$ was obtained with eight counters with Hamamatsu SiPMs. These results suggest that the design resolution is achievable in the MEG II experiment.

  15. The AMS-01 Aerogel Threshold Cherenkov counter

    Energy Technology Data Exchange (ETDEWEB)

    Barancourt, D.; Barao, F.; Barbier, G.; Barreira, G.; Buenerd, M.; Castellini, G.; Choumilov, E.; Favier, J.; Fouque, N.; Gougas, A.; Hermel, V.; Kossakowski, R.; Laborie, G.; Laurenti, G.; Lee, S.-C.; Mayet, F. E-mail: frederic.mayet@isn.in2p3.fr; Meillon, B.; Oyang, Y.-T.; Plyaskin, V.; Pojidaev, V.; Rossin, C.; Santos, D.; Vezzu, F.; Vialle, J.P

    2001-06-11

    The Alpha Magnetic Spectrometer in a precursor version (AMS-01), was flown in June 1998 on a 51.6 deg. orbit and at altitudes ranging between 320 and 390 km, on board of the space shuttle Discovery (flight STS-91). AMS-01 included an Aerogel Threshold Cherenkov counter (ATC) to separate p-bar from e{sup -} and e{sup +} from p, for momenta below 3.5 GeV/c. This paper presents a description of the ATC counter and reports on its performances during the flight STS-91.

  16. The AMS-01 Aerogel Threshold Cherenkov counter

    CERN Document Server

    Barancourt, D; Barbier, G; Barreira, G; Buénerd, M; Castellini, G; Choumilov, E; Favier, Jean; Fouque, N; Gougas, Andreas; Hermel, V; Kossakowski, R; Laborie, G; Laurenti, G; Lee, S C; Mayet, F; Meillon, B; Oyang, J Y T; Plyaskin, V; Pozhidaev, V; Rossin, C; Santos, D; Vezzu, F; Vialle, J P

    2001-01-01

    The Alpha Magnetic Spectrometer in a precursor version (AMS-01), was flown in June 1998 on a 51.6 degrees orbit and at altitudes ranging between 320 and 390 km, on board of the space shuttle Discovery (flight STS-91). AMS-01 included an Aerogel Threshold Cherenkov counter (ATC) to separate antiprotons from electrons and positrons from protons, for momenta below 3.5 GeV/c. This paper presents a description of the ATC counter and reports on its performances during the flight STS-91.

  17. Analysis of counter-rotating wind turbines

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Zakkam, Vinod Arun Kumar; Sørensen, Jens Nørkær

    2007-01-01

    This paper presents a study on the performance of a wind turbine with two counter-rotating (CRWT) rotors. The characteristics of the two counter-rotating rotors are on a 3-bladed Nordtank 500 kW rotor. The analysis has been carried out by using an Actuator Line technique implemented in the Navier......-Stokes code EllipSys3D. The analysis shows that the Annual Energy Production can be increased to about 43.5 %, as compared to a wind turbine with a single rotor. In order to determine the optimal settings of the CRWT turbine, parameters such as distance between two rotors and rotational speed have been...

  18. Development of DUPIC safeguards neutron counter

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Gil; Cha, Hong Ryul; Kim, Ho Dong; Hong, Jong Sook; Kang, Hee Young

    1999-08-01

    KAERI, in cooperation with LANL, developed DSNC (DUPIC Safeguards Neutron Counter) for safeguards implementing on DUPIC process which is under development by KAERI for direct use of spent PWR fuel in CANDU reactors. DSNC is a well-type neutron coincidence counter with substantial shielding to protect system from high gamma radiation of spent fuel. General development procedures in terms of design, manufacturing, fabrication, cold and hot test, performance test for DSNC authentication by KAERI-IAEA-LANL are described in this report. It is expected that the techniques related DSNC development and associated neutron detection and evaluation method could be applied for safeguards improvement. (Author). 20 refs., 16 tabs. 98 figs.

  19. Development of DUPIC safeguards neutron counter

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Gil; Cha, Hong Ryul; Kim, Ho Dong; Hong, Jong Sook; Kang, Hee Young

    1999-08-01

    KAERI, in cooperation with LANL, developed DSNC (DUPIC Safeguards Neutron Counter) for safeguards implementing on DUPIC process which is under development by KAERI for direct use of spent PWR fuel in CANDU reactors. DSNC is a well-type neutron coincidence counter with substantial shielding to protect system from high gamma radiation of spent fuel. General development procedures in terms of design, manufacturing, fabrication, cold and hot test, performance test for DSNC authentication by KAERI-IAEA-LANL are described in this report. It is expected that the techniques related DSNC development and associated neutron detection and evaluation method could be applied for safeguards improvement. (Author). 20 refs., 16 tabs. 98 figs.

  20. Wakefields generated by collisional neutrinos in neutral-electron-positron-ion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Tinakiche, Nouara [Faculty of Sciences, Department of Physics, University of Boumeredes U.M.B.B., Boumerdes 35000 (Algeria)

    2015-12-15

    A classical fluid description is adopted to investigate nonlinear interaction between an electron-type neutrino beam and a relativistic collisionless unmagnetized neutral-electron-positron-ion plasma. In this work, we consider the collisions of the neutrinos with neutrals in the plasma and study their effect on the generation of wakefields in presence of a fraction of ions in a neutral-electron-positron plasma. The results obtained in the present work are interpreted and compared with previous studies.

  1. The Proportional Counter Source For The Low Energy Calibration Of The Sudbury Neutrino Observatory

    CERN Document Server

    Dalnoki-Veress, F J

    2003-01-01

    It is imperative that if a clean measurement is to be made of the Charged Current (CC) to Neutral Current (NC) ratio and the CC spectral distortion in the Sudbury Neutrino Observatory, the low energy background must be very well understood. For this reason a technique has been developed, so that each isotope of the background in the D2O can be measured. The technique relies on a proportional counter (PCS), which acts both as a detector as well as a source. If various sources such as 228Th are placed on the anode of the proportional counter, the beta-decay is tagged by the PCS and the Čerenkov radiation that is produced is detected by SNO. The method aims to make a background and distortion free measurement of the SNO detector response to a 228Th source. This thesis discusses the construction, development, testing, quality control and assurance, deployment and analysis of the PCS.

  2. Generation of intense magnetic field in a counter-streaming system

    Science.gov (United States)

    Yin, Yan

    2016-10-01

    Intense magnetic field generation by excitation of Weibel instability in dense plasmas has been investigated using particle-in-cell (PIC) simulations. As energetic electrons driven by laser propagate in dense plasmas, a return current is excited to compensate the charge neutrality offset. In such a counter-streaming system, Weibel instability is driven, leading to current filamentation and magnetic field generation. The current filaments self-organize in coaxial structures where the relativistic current in the center is surrounded by the return current sheath and intense magnetic field. The magnetic field peaks in the current center with magnitude as high as several hundreds of MegaGauss, and decreases to zero outside the relativistic current. The influences of counter-streaming density and energy on the magnetic field generation are examined.

  3. Ultracold neutral plasmas

    Science.gov (United States)

    Lyon, M.; Rolston, S. L.

    2017-01-01

    By photoionizing samples of laser-cooled atoms with laser light tuned just above the ionization limit, plasmas can be created with electron and ion temperatures below 10 K. These ultracold neutral plasmas have extended the temperature bounds of plasma physics by two orders of magnitude. Table-top experiments, using many of the tools from atomic physics, allow for the study of plasma phenomena in this new regime with independent control over the density and temperature of the plasma through the excitation process. Characteristic of these systems is an inhomogeneous density profile, inherited from the density distribution of the laser-cooled neutral atom sample. Most work has dealt with unconfined plasmas in vacuum, which expand outward at velocities of order 100 m/s, governed by electron pressure, and with lifetimes of order 100 μs, limited by stray electric fields. Using detection of charged particles and optical detection techniques, a wide variety of properties and phenomena have been observed, including expansion dynamics, collective excitations in both the electrons and ions, and collisional properties. Through three-body recombination collisions, the plasmas rapidly form Rydberg atoms, and clouds of cold Rydberg atoms have been observed to spontaneously avalanche ionize to form plasmas. Of particular interest is the possibility of the formation of strongly coupled plasmas, where Coulomb forces dominate thermal motion and correlations become important. The strongest impediment to strong coupling is disorder-induced heating, a process in which Coulomb energy from an initially disordered sample is converted into thermal energy. This restricts electrons to a weakly coupled regime and leaves the ions barely within the strongly coupled regime. This review will give an overview of the field of ultracold neutral plasmas, from its inception in 1999 to current work, including efforts to increase strong coupling and effects on plasma properties due to strong coupling.

  4. Heavy ion beam transport and focusing with an insulator guide in inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Someya, T.; Nakamura, T.; Sasaki, J.; Kawata, S. [Utsunomiya Univ., Dept. of Energy and Environment Sciences, Utsunomiya, Tochigi (Japan)

    2001-09-01

    One of the key issues on the heavy ion beam inertial confinement fusion is an efficient transport and beam focusing. To get a fine focusing on the fuel pellet, neutralization of the space change of an incident beam is required. The space charge of beam has to be neutralized for the fine focusing. In this paper, we propose to employ an insulator tube guide, through which a heavy ion beam is transported and focused. We confirm that the beam space charge is effectively neutralized by electrons emitted from the insulator beam guide and the ion beam fine focusing is realized. This result shows a possibility of a good beam focusing by the insulator beam guide. (author)

  5. The Weak Neutral Current

    CERN Document Server

    Erler, Jens

    2013-01-01

    This is a review of electroweak precision physics with particular emphasis on low-energy precision measurements in the neutral current sector of the electroweak theory and includes future experimental prospects and the theoretical challenges one faces to interpret these observables. Within the minimal Standard Model they serve as determinations of the weak mixing angle which are competitive with and complementary to those obtained near the Z-resonance. In the context of new physics beyond the Standard Model these measurements are crucial to discriminate between models and to reduce the allowed parameter space within a given model. We illustrate this for the minimal supersymmetric Standard Model with or without R-parity.

  6. Mod en neutral seksualitet!

    DEFF Research Database (Denmark)

    Leer, Jonatan

    2013-01-01

    the paradigm”. This notion was presented at a series of lectures at Collège de France in 1977. Through a reading of Barthes’s autobiography, Roland Barthes par Roland Barthes (1975), the article demonstrates how Barthes in this text tries to outplay the paradigms that rules over the hegemonic understanding...... of gender and sexuality; also the fragmented text presents a vision of a sexual utopia, a neutral sexuality, that tries – like the queer theory – to go and think beyond a binary conception of gender and sexuality. Finally, it is suggested that we should start to think about a movement of “French queer...

  7. Design and Characterization of a Neutralized-Transport Experiment for Heavy-Ion Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, E; Eylon, S; Roy, P; Yu, S S; Anders, A; Bieniosek, F M; Greenway, W G; Logan, B G; MacGill, R A; Shuman, D B; Vanecek, D L; Waldron, W L; Sharp, W M; Houck, T L; Davidson, R C; Efthimion, P C; Gilson, E P; Sefkow, A B; Welch, D R; Rose, D V; Olson, C L

    2004-05-24

    In heavy-ion inertial-confinement fusion systems, intense beams of ions must be transported from the exit of the final focus magnet system through the fusion chamber to hit millimeter-sized spots on the target. Effective plasma neutralization of intense ion beams in this final transport is essential for a heavy-ion fusion power plant to be economically competitive. The physics of neutralized drift has been studied extensively with particle-in-cell simulations. To provide quantitative comparisons of theoretical predictions with experiment, the Virtual National Laboratory for Heavy Ion Fusion has completed the construction and has begun experimentation with the Neutralized Transport Experiment (NTX). The experiment consists of three main sections, each with its own physics issues. The injector is designed to generate a very high-brightness, space-charge-dominated potassium beam while still allowing variable perveance by a beam aperturing technique. The magnetic-focusing section, consisting of four pulsed magnetic quadrupoles, permits the study of beam tuning, as well as the effects of phase space dilution due to higher-order nonlinear fields. In the final section, a converging ion beam exiting the magnetic section is transported through a drift region with plasma sources for beam neutralization, and the final spot size is measured under various conditions of neutralization. In this paper, we discuss the design and characterization of the three sections in detail and present the first results from the experiment.

  8. Design and characterization of a neutralized-transport experiment for heavy-ion fusion

    Energy Technology Data Exchange (ETDEWEB)

    Henestroza, E.; Eylon, S.; Roy, P.K.; Yu, S.S.; Anders, A.; Bieniosek, F.M.; Greenway, W.G.; Logan, B.G.; MacGill, R.A.; Shuman, D.B.; Vanecek, D.L.; Waldron, W.L.; Sharp, W.M.; Houck, T.L.; Davidson, R.C.; Efthimion, P.C.; Gilson, E.P.; Sefkow, A.B.; Welch, D.R.; Rose, D.V.; Olson, C.L.

    2004-03-14

    In heavy-ion inertial-confinement fusion systems, intense beams of ions must be transported from the exit of the final focus magnet system through the fusion chamber to hit millimeter-sized spots on the target. Effective plasma neutralization of intense ion beams in this final transport is essential for a heavy-ion fusion power plant to be economically competitive. The physics of neutralized drift has been studied extensively with particle-in-cell simulations. To provide quantitative comparisons of theoretical predictions with experiment, the Virtual National Laboratory for Heavy Ion Fusion has completed the construction and has begun experimentation with the Neutralized Transport Experiment (NTX). The experiment consists of three main sections, each with its own physics issues. The injector is designed to generate a very high-brightness, space-charge-dominated potassium beam while still allowing variable perveance by a beam aperturing technique. The magnetic-focusing section, consisting of four pulsed magnetic quadrupoles, permits the study of beam tuning, as well as the effects of phase space dilution due to higher-order nonlinear fields. In the final section, the converging ion beam exiting the magnetic section is transported through a drift region with plasma sources for beam neutralization, and the final spot size is measured under various conditions of neutralization. In this paper, we discuss the design and characterization of the three sections in detail and present initial results from the experiment.

  9. Upaya Perumusan Prinsip Counter Accounting Melalui Filosofi Punk Sebagai Counter Culture

    Directory of Open Access Journals (Sweden)

    Dayno Utama

    2015-12-01

    Full Text Available The aim of this research is to demonstrate that resistance to mainstream research contained in top/elite accounting journals for sparking creativity and innovation unconsciously has utilized the philosophy of punk. The research method of this research is argumentation technique. The result of this research shows that the philosophy of punk as counter culture can be utilized for accounting research through formulation the accounting principles namely counter accounting. Creative and innovative accounting as forms of counter accounting towards mainstream accounting tradition especially in elite journals, will not pervade in a short time.

  10. Neutral-current detection in the Sudbury Neutrino Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Bowles, T.J.; Doe, P.J.; Fowler, M.M.; Hime, A.; Robertson, R.G.H.; Thornewell, P.M.; Wilhelmy, J.B.; Wilkerson, J.F.; Wouters, J.M.

    1993-06-01

    The Sudbury Neutrino Observatory (SNO) will have the capability of detecting all active species of neutrinos with energies greater than 2.2 MeV by the neutral-current disintegration of deuterium. The comparison of this rate with the rate of inverse beta decay of the deuteron will yield a nearly model-independent answer to the question of whether electron neutrinos from the sun oscillate into mu or tau neutrinos. The signal of a neutral-current interaction is the liberation of a free neutron in the heavy-water detector, and we discuss a technique employing {sup 3}He proportional counters for registering these neutrons, particularly from the standpoint of the ultra-low backgrounds needed.

  11. Neutral-current detection in the Sudbury Neutrino Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Bowles, T.J.; Doe, P.J.; Fowler, M.M.; Hime, A.; Robertson, R.G.H.; Thornewell, P.M.; Wilhelmy, J.B.; Wilkerson, J.F.; Wouters, J.M.

    1993-01-01

    The Sudbury Neutrino Observatory (SNO) will have the capability of detecting all active species of neutrinos with energies greater than 2.2 MeV by the neutral-current disintegration of deuterium. The comparison of this rate with the rate of inverse beta decay of the deuteron will yield a nearly model-independent answer to the question of whether electron neutrinos from the sun oscillate into mu or tau neutrinos. The signal of a neutral-current interaction is the liberation of a free neutron in the heavy-water detector, and we discuss a technique employing [sup 3]He proportional counters for registering these neutrons, particularly from the standpoint of the ultra-low backgrounds needed.

  12. Is /h/ phonetically neutral?

    Science.gov (United States)

    Robb, Michael P; Chen, Yang

    2009-11-01

    Use of /h/ in the phrase, 'Say /hVC/ again' has been tacitly assumed to provide a neutral phonetic context in which to study the articulatory characteristics of speech either preceding or following /h/ articulation. Yet, assessment of the stability or neutrality of /h/ has gone untested. The current study sought to determine whether articulation of /h/ differs according to sex and language accent, as well as to examine its influence on subsequent vowel articulation. Selected acoustic features of /hVC/ were measured in 40 speakers of American English (AE) and 40 speakers of Mandarin-accented English (MAE). Results of an analysis of /h/ duration revealed no sex differences within each language group, however considerable variation was found according to accented vs unaccented English. Clear sex differences were found for the production of /h/, occurring more often among male speakers regardless of language variety. Considerable variation in production of /h/ was found between language groups. Analysis of vowel formant frequencies immediately following /h/ articulation indicated minimal coarticulatory effects for both AE and MAE speakers. The present results appear to support the suggestion that /h/ is not exclusively sex-linked and may indeed vary according to non-biological factors. In spite of these variations, /h/ articulation appears to have a negligible influence on neighbouring vowel articulation.

  13. Scrape-off layer-induced beam density fluctuations and their effect on beam emission spectroscopy

    Science.gov (United States)

    Moulton, D.; Marandet, Y.; Tamain, P.; Dif-Pradalier, G.

    2015-07-01

    A statistical model is presented to calculate the magnitude of beam density fluctuations generated by a turbulent scrape-off layer (SOL). It is shown that the SOL can induce neutral beam density fluctuations of a similar magnitude to the plasma density fluctuations in the core, potentially corrupting beam emission spectroscopy measurements. The degree of corruption is quantified by combining simulations of beam and plasma density fluctuations inside a simulated measurement window. A change in pitch angle from the separatrix to the measurement window is found to reduce the effect of beam fluctuations, whose largest effect is to significantly reduce the measured correlation time.

  14. COUNTER-ROTATION IN RELATIVISTIC MAGNETOHYDRODYNAMIC JETS

    Energy Technology Data Exchange (ETDEWEB)

    Cayatte, V.; Sauty, C. [Laboratoire Univers et Théories, Observatoire de Paris, UMR 8102 du CNRS, Université Paris Diderot, F-92190 Meudon (France); Vlahakis, N.; Tsinganos, K. [Department of Astrophysics, Astronomy and Mechanics, Faculty of Physics, University of Athens, 15784 Zografos, Athens (Greece); Matsakos, T. [Department of Astronomy and Astrophysics, The University of Chicago, Chicago, IL 60637 (United States); Lima, J. J. G., E-mail: veronique.cayatte@obspm.fr [Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal)

    2014-06-10

    Young stellar object observations suggest that some jets rotate in the opposite direction with respect to their disk. In a recent study, Sauty et al. showed that this does not contradict the magnetocentrifugal mechanism that is believed to launch such outflows. Motion signatures that are transverse to the jet axis, in two opposite directions, have recently been measured in M87. One possible interpretation of this motion is that of counter-rotating knots. Here, we extend our previous analytical derivation of counter-rotation to relativistic jets, demonstrating that counter-rotation can indeed take place under rather general conditions. We show that both the magnetic field and a non-negligible enthalpy are necessary at the origin of counter-rotating outflows, and that the effect is associated with a transfer of energy flux from the matter to the electromagnetic field. This can be realized in three cases: if a decreasing enthalpy causes an increase of the Poynting flux, if the flow decelerates, or if strong gradients of the magnetic field are present. An illustration of the involved mechanism is given by an example of a relativistic magnetohydrodynamic jet simulation.

  15. Can counter-stereotypes boost flexible thinking?

    NARCIS (Netherlands)

    M.A. Goclowska; R.J. Crisp; K. Labuschagne

    2012-01-01

    To reduce prejudice psychologists design interventions requiring people to think of counter-stereotypes (i.e., people who defy stereotypic expectations—a strong woman, a Black President). Grounded in the idea that stereotypes constrain the ability to think flexibly, we propose that thinking of count

  16. International perspectives on countering school segregation

    NARCIS (Netherlands)

    Bakker, J.T.A.; Denessen, E.J.P.G.; Peters, T.J.M.; Walraven, G.

    2010-01-01

    School segregation is perceived as an unyielding problem worldwide, which is manifest along both ethnic and socio-economic lines. With this edited volume we aim to share information about school segregation and policies focused on countering school segregation from an international perspective. Many

  17. Counter Trafficking System Development "Analysis Training Program"

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Dennis C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2010-12-01

    This document will detail the training curriculum for the Counter-Trafficking System Development (CTSD) Analysis Modules and Lesson Plans are derived from the United States Military, Department of Energy doctrine and Lawrence Livermore National Laboratory (LLNL), Global Security (GS) S Program.

  18. Can counter-stereotypes boost flexible thinking?

    NARCIS (Netherlands)

    Goclowska, M.A.; Crisp, R.J.; Labuschagne, K.

    2013-01-01

    To reduce prejudice psychologists design interventions requiring people to think of counter-stereotypes (i.e., people who defy stereotypic expectations—a strong woman, a Black President). Grounded in the idea that stereotypes constrain the ability to think flexibly, we propose that thinking of count

  19. Cerenkov counters at the Omega Facility

    CERN Multimedia

    1975-01-01

    P. Petroff on the left. Here one sees both the gas Cerenkov counters sitting in front of the magnet to select forward emitted particles. The smaller one, working at high pressure, sits nearest to the Omega magnet (see photo 7505073X), the other (see photo 7505071X) works at atmospheric pressure.

  20. One-Counter Markov Decision Processes

    NARCIS (Netherlands)

    Brazdil, T.; Brozek, V.; Etessami, K.; Kucera, A.; Wojtczak, D.K.; Charikar, M.

    2010-01-01

    We study the computational complexity of central analysis problems for One-Counter Markov Decision Processes (OC-MDPs), a class of finitely-presented, countable-state MDPs. OC-MDPs are equivalent to a controlled extension of (discrete-time) Quasi-Birth-Death processes (QBDs), a stochastic model stud

  1. Ultrafine Condensation Particle Counter Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Kuang, C. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-02-01

    The Model 3776 Ultrafine Condensation Particle Counter (UCPC; pictured in Appendix A) is designed for researchers interested in airborne particles smaller than 20 nm. With sensitivity to particles down to 2.5 nm in diameter, this UCPC is ideally suited for atmospheric and climate research, particle formation and growth studies, combustion and engine exhaust research, and nanotechnology research.

  2. Novel concept for neutron detection: proportional counter filled with 10B nanoparticle aerosol

    Science.gov (United States)

    Amaro, F. D.; Monteiro, C. M. B.; dos Santos, J. M. F.; Antognini, A.

    2017-01-01

    The high neutron detection efficiency, good gamma-ray discrimination and non-toxicity of 3He made of proportional counters filled with this gas the obvious choice for neutron detection, particularly in radiation portal monitors (RPM), used to control the illicit transport of nuclear material, of which neutron detectors are key components. 3He is very rare and during the last decade this gas has become increasingly difficult to acquire. With the exception of BF3, which is toxic, no other gas can be used for neutron detection in proportional counters. We present an alternative where the 3He atoms are replaced by nanoparticles made of another neutron sensitive material, 10B. The particles are dispersed in a gaseous volume, forming an aerosol with neutron sensitive properties. A proportional counter filled with such aerosol was exposed to a thermal neutron beam and the recorded response indicates that the neutrons have interacted with the particles in the aerosol. This original technique, which transforms a standard proportional gas mixture into a neutron sensitive aerosol, is a breakthrough in the field of radiation detection and has the potential to become an alternative to the use of 3He in proportional counters. PMID:28181520

  3. A 10B-based neutron detector with stacked Multiwire Proportional Counters and macrostructured cathodes

    CERN Document Server

    Stefanescu, I; Birch, J; Defendi, I; Hall-Wilton, R; Hoglund, C; Hultman, L; Zee, M; Zeitelhack, K

    2013-01-01

    We present the results of the measurements of the detection efficiency for a 4.7 \\r{A} neutron beam incident upon a detector incorporating a stack of up to five MultiWire Proportional Counters (MWPC) with Boron-coated cathodes. The cathodes were made of Aluminum and had a surface exhibiting millimeter-deep V-shaped grooves of 45{\\deg}, upon which the thin Boron film was deposited by DC magnetron sputtering. The incident neutrons interacting with the converter layer deposited on the sidewalls of the grooves have a higher capture probability, owing to the larger effective absorption film thickness. This leads to a higher overall detection efficiency for the grooved cathode when compared to a cathode with a flat surface. Both the experimental results and the predictions of the GEANT4 model suggests that a 5-counter detector stack with coated grooved cathodes has the same efficiency as a 7-counter stack with flat cathodes. The reduction in the number of counters in the stack without altering the detection efficie...

  4. Novel concept for neutron detection: proportional counter filled with 10B nanoparticle aerosol

    Science.gov (United States)

    Amaro, F. D.; Monteiro, C. M. B.; Dos Santos, J. M. F.; Antognini, A.

    2017-02-01

    The high neutron detection efficiency, good gamma-ray discrimination and non-toxicity of 3He made of proportional counters filled with this gas the obvious choice for neutron detection, particularly in radiation portal monitors (RPM), used to control the illicit transport of nuclear material, of which neutron detectors are key components. 3He is very rare and during the last decade this gas has become increasingly difficult to acquire. With the exception of BF3, which is toxic, no other gas can be used for neutron detection in proportional counters. We present an alternative where the 3He atoms are replaced by nanoparticles made of another neutron sensitive material, 10B. The particles are dispersed in a gaseous volume, forming an aerosol with neutron sensitive properties. A proportional counter filled with such aerosol was exposed to a thermal neutron beam and the recorded response indicates that the neutrons have interacted with the particles in the aerosol. This original technique, which transforms a standard proportional gas mixture into a neutron sensitive aerosol, is a breakthrough in the field of radiation detection and has the potential to become an alternative to the use of 3He in proportional counters.

  5. CHICO2, a two-dimensional pixelated parallel-plate avalanche counter

    Energy Technology Data Exchange (ETDEWEB)

    Wu, C.Y., E-mail: wu24@llnl.gov [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Cline, D.; Hayes, A.; Flight, R.S.; Melchionna, A.M.; Zhou, C. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Lee, I.Y. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Swan, D. [Swan Research LLC, Owosso, MI 48867 (United States); Fox, R. [CAEN Technologies, INC, Staten Island, NY 10305 (United States); Anderson, J.T. [High Energy Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2016-04-01

    CHICO2 (Compact Heavy Ion COunter), is a large solid-angle, charged-particle detector array developed to provide both θ and ϕ angle resolutions matching those of GRETINA (Gamma-Ray Energy Tracking In-beam Nuclear Array). CHICO2 was successfully tested at the Argonne National Laboratory where it was fielded as an auxiliary detector with GRETINA for γ-ray spectroscopic studies of nuclei using a {sup 252}Cf spontaneous fission source, stable beams, and radioactive beams from CARIBU. In field tests of the {sup 72,76}Ge beams on a 0.5 mg/cm{sup 2208}Pb target at the sub-barrier energy, CHICO2 provided charged-particle angle resolutions (FWHM) of 1.55° in θ and 2.47° in ϕ. This achieves the design goal for both coordinates assuming a beam-spot size (>3 mm) and the target thickness (>0.5 mg/cm{sup 2}). The combined angular resolution of GRETINA/CHICO2 resulted in a Doppler-shift corrected energy resolution of 0.60% for 1 MeV coincident de-excitation γ-rays. This is nearly a factor of two improvements in resolution and sensitivity compared to Gammasphere/CHICO. Kinematically-coincident detection of scattered ions by CHICO2 still maintains the mass resolution (ΔM/M) of ~5% that enhanced isolation of scattered weak beams of interest from scattered contaminant beams.

  6. Running Loose or Getting Lost: How HIV-1 Counters and Capitalizes on APOBEC3-Induced Mutagenesis through Its Vif Protein

    OpenAIRE

    Christel Kamp; Dieter Häussinger; Jörg Zielonka; Carsten Münk; Jensen, Björn-Erik O.

    2012-01-01

    Human immunodeficiency virus-1 (HIV-1) dynamics reflect an intricate balance within the viruses’ host. The virus relies on host replication factors, but must escape or counter its host’s antiviral restriction factors. The interaction between the HIV-1 protein Vif and many cellular restriction factors from the APOBEC3 protein family is a prominent example of this evolutionary arms race. The viral infectivity factor (Vif) protein largely neutralizes APOBEC3 proteins, which c...

  7. Precision measurement of the cross section of charged-current and neutral current processes at large Q{sup 2} at HERA with the polarized-electron beam; Mesures de precision de la section efficace des processus courant charge et courant neutre a grand Q{sup 2} a HERA avec le faisceau d'electrons polarises

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Trong Hieu

    2011-04-15

    The inclusive cross sections for both charged and neutral current processes have been measured in interactions of longitudinally polarized electrons (positrons) with unpolarized protons using the full data samples collected by H1 at HERA-II. The data taken at a center-of-mass energy of 319 GeV correspond to an integrated luminosity of 149.1 pb{sup -1} and 180.0 pb{sup -1} for e{sup -}p and e{sup +}p collisions, representing an increase in statistics of a factor of 10 and 2, respectively, over the data from HERA-I. The measured double differential cross sections d{sup 2}{sigma}/dxdQ{sup 2} cover more than two orders of magnitude in both Q{sup 2}, the negative four-momentum transfer squared, up to 30000 GeV{sup 2}, and Bjorken x, down to 0.003. The cross section data are compared to predictions of the Standard Model which is able to provide a good description of the data. The polarization asymmetry as a function of Q{sup 2} is measured with improved precision, confirming the previous observation of P violation effect in neutral current ep scattering at distances down to 10{sup -18} m. The total cross sections of the charged current process, for Q{sup 2} > 400 GeV{sup 2} and inelasticity y < 0.9 are measured for 4 independent data samples with e{sup {+-}} beams and different polarization values. Together with the corresponding cross section obtained from the previously published unpolarized data, the polarization dependence of the charged current cross section is measured and found to be in agreement with the Standard Model prediction with the absence of right-handed charged current. The cross sections are combined with previously published data from H1 to obtain the most precise unpolarized measurements. These are used to extract the structure function xF{sub 3}{sup {gamma}}{sup Z} which is sensitive to the valence quark distributions down to low x values. The new cross sections have also been used in a combined electroweak and QCD fit to significantly improve the

  8. PROTON HEATING IN SOLAR WIND COMPRESSIBLE TURBULENCE WITH COLLISIONS BETWEEN COUNTER-PROPAGATING WAVES

    Energy Technology Data Exchange (ETDEWEB)

    He, Jiansen; Tu, Chuanyi; Wang, Linghua; Pei, Zhongtian [School of Earth and Space Sciences, Peking University, Beijing, 100871 (China); Marsch, Eckart [Institute for Experimental and Applied Physics, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel (Germany); Chen, Christopher H. K. [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom); Zhang, Lei [Sate Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100190 (China); Salem, Chadi S.; Bale, Stuart D., E-mail: jshept@gmail.com [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)

    2015-11-10

    Magnetohydronamic turbulence is believed to play a crucial role in heating laboratory, space, and astrophysical plasmas. However, the precise connection between the turbulent fluctuations and the particle kinetics has not yet been established. Here we present clear evidence of plasma turbulence heating based on diagnosed wave features and proton velocity distributions from solar wind measurements by the Wind spacecraft. For the first time, we can report the simultaneous observation of counter-propagating magnetohydrodynamic waves in the solar wind turbulence. As opposed to the traditional paradigm with counter-propagating Alfvén waves (AWs), anti-sunward AWs are encountered by sunward slow magnetosonic waves (SMWs) in this new type of solar wind compressible turbulence. The counter-propagating AWs and SWs correspond, respectively, to the dominant and sub-dominant populations of the imbalanced Elsässer variables. Nonlinear interactions between the AWs and SMWs are inferred from the non-orthogonality between the possible oscillation direction of one wave and the possible propagation direction of the other. The associated protons are revealed to exhibit bi-directional asymmetric beams in their velocity distributions: sunward beams appear in short, narrow patterns and anti-sunward in broad extended tails. It is suggested that multiple types of wave–particle interactions, i.e., cyclotron and Landau resonances with AWs and SMWs at kinetic scales, are taking place to jointly heat the protons perpendicular and in parallel.

  9. Infrared imaging diagnostics for INTF ion beam

    Science.gov (United States)

    Sudhir, D.; Bandyopadhyay, M.; Pandey, R.; Joshi, J.; Yadav, A.; Rotti, C.; Bhuyan, M.; Bansal, G.; Soni, J.; Tyagi, H.; Pandya, K.; Chakraborty, A.

    2015-04-01

    In India, testing facility named INTF [1] (Indian test facility) is being built in Institute for Plasma Research to characterize ITER-Diagnostic Neutral Beam (DNB). INTF is expected to deliver 60A negative hydrogen ion beam current of energy 100keV. The beam will be operated with 5Hz modulation having 3s ON/20s OFF duty cycle. To characterize the beam parameters several diagnostics are at different stages of design and development. One of them will be a beam dump, made of carbon fiber composite (CFC) plates placed perpendicular to the beam direction at a distance lm approximately. The beam dump needs to handle ˜ 6MW of beam power with peak power density ˜ 38.5MW/m2. The diagnostic is based on thermal (infra-red - IR) imaging of the footprint of the 1280 beamlets falling on the beam dump using four IR cameras from the rear side of the dump. The beam dump will be able to measure beam uniformity, beamlet divergence. It may give information on relative variation of negative ion stripping losses for different beam pulses. The design of this CFC based beam dump needs to address several physics and engineering issues, including some specific inputs from manufacturers. The manuscript will describe an overview of the diagnostic system and its design methodology highlighting those issues and the present status of its development.

  10. Counter-Narratives and the Unrehearsed Stories Counter-Terrorists Unwittingly Produce.

    OpenAIRE

    Beatrice de Graaf

    2009-01-01

    Governments produce both deliberate and involuntary (and less conscious) narratives when countering terrorism. The thesis of this article is that such unintended messages can be much more powerful and consequential than is realized; in fact, they can completely contradict the intended official 'counter-narrative'. To substantiate this hypothesis, the author looks at the experience of the German Federal Republic in the 1970s and beyond when state and society were confronted with the Red Army F...

  11. Splitting of high power, cw proton beams

    CERN Document Server

    Facco, Alberto; Berkovits, Dan; Yamane, Isao

    2007-01-01

    A simple method for splitting a high power, continuous wave (cw) proton beam in two or more branches with low losses has been developed in the framework of the EURISOL (European Isotope Separation On-Line adioactive Ion Beam Facility) design study. The aim of the system is to deliver up to 4 MW of H beam to the main radioactive ion beam production target, and up to 100 kWof proton beams to three more targets, simultaneously. A three-step method is used, which includes magnetic neutralization of a fractionof the main H- beam, magnetic splitting of H- and H0, and stripping of H0 to H+. The method allowsslow raising and individual fine adjustment of the beam intensity in each branch.

  12. Production, Characterization, and Measurement of H(D) Beams on the ORNL Merged-Beams Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, J. D. [University of Toledo, Toledo, OH; Kvale, Thomas Jay [University of Toledo, Toledo, OH; Strasser, S. M. [Albion College; Seely, D. G. [Albion College; Havener, Charles C [ORNL

    2009-01-01

    Total cross section measurements of electron capture processes are being studied for low-energy, Aq++H(D) collisions using the Ion-Atom Merged-Beams apparatus at the Multicharged Ion Research Facility (MIRF) at Oak Ridge National Laboratory (ORNL). On this apparatus, a modified Faraday cup detector is used to measure the intensity of the neutral beam. The conversion of the measured electrical current to the true neutral particle beam current is necessary to accurately determine the true cross section values. Inherent in this conversion process is the number of secondary electrons (gamma) emitted from the surface of the detector upon impact of an atom. The method employed to determine gamma and its role in the absolute electron capture measurements at ORNL-MIRF are presented. With a recent upgrade to the apparatus, the neutral beam H(D) production technique has been improved and is discussed in detail in this paper.

  13. Experimental Study on Voided Reinforced Concrete Beams with Polythene Balls

    Science.gov (United States)

    Sivaneshan, P.; Harishankar, S.

    2017-07-01

    The primary component in any structure is concrete, that exist in buildings and bridges. In present situation, a serious problems faced by construction industry is exhaustive use of raw materials. Recent times, various methods are being adopted to limit the use of concrete. In structural elements like beams, polythene balls can be induced to reduce the usage of concrete. A simply supported reinforced concrete beam has two zones, one above neutral axis and other below neutral axis. The region below neutral axis is in tension and above neutral axis is in compression. As concrete is weak in tension, steel reinforcements are provided in tension zone. The concrete below the neutral axis acts as a stress transfer medium between the compression zone and tension zone. The concrete above the neutral axis takes minimum stress so that we could partially replace the concrete above neutral axis by creating air voids using recycled polythene balls. Polythene balls of varying diameters of 75 mm, 65 mm and 35 mm were partially replaced in compression zone. Hence the usage of concrete in beams and self-weight of the beams got reduced considerably. The Load carrying capacity, Deflection of beams and crack patterns were studied and compared with conventional reinforced concrete beams.

  14. Analysis of neutral hydrogenic emission spectra in a tokamak

    Science.gov (United States)

    Ko, J.; Chung, J.; Jaspers, R. J. E.

    2015-10-01

    Balmer-α radiation by the excitation of thermal and fast neutral hydrogenic particles has been investigated in a magnetically confined fusion device, or tokamak, from the Korea Superconducting Tokamak Advanced Research (KSTAR). From the diagnostic point of view, the emission from thermal neutrals is associated with passive spectroscopy and that from energetic neutrals that are usually injected from the outside of the tokamak to the active spectroscopy. The passive spectroscopic measurement for the thermal Balmer-α emission from deuterium and hydrogen estimates the relative concentration of hydrogen in a deuterium-fueled plasma and therefore, makes a useful tool to monitor the vacuum wall condition. The ratio of hydrogen to deuterium obtained from this measurement qualitatively correlates with the energy confinement of the plasma. The Doppler-shifted Balmer-α components from the fast neutrals features the spectrum of the motional Stark effect (MSE) which is an essential principle for the measurement of the magnetic pitch angle profile. Characterization of this active MSE spectra, especially with multiple neutral beam lines crossing along the observation line of sight, has been done for the guideline of the multi-ion-source heating beam operation and for the optimization of the narrow bandpass filters that are required for the polarimeter-based MSE diagnostic system under construction at KSTAR.

  15. Recent results from studies of electron beam phenomena in space plasmas

    Science.gov (United States)

    Neubert, Torsten; Banks, Peter M.

    1992-01-01

    The paper examines selected results from experiments, performed in 1980s, involving the ejection of beams of electrons from spacecraft. Special attention is given to the basic processes associated with the spacecraft charging, passive current collection, beam-atmosphere interactions, beam-plasma interactions, and neutral gas emission. Consideration is also given to future experiments on active electron beam ejections in space.

  16. Simultaneous induction acceleration and bunching in the Neutralized Drift Compression Experiment

    Science.gov (United States)

    Seidl, Peter; Bazouin, G.; Lidia, S. M.; Roy, P. K.; Waldron, W. L.

    2009-11-01

    The Neutralized Drift Compression Experiment uses a ramped, bipolar induction module waveform to compress the beam to nanosecond bunches for the study of warm dense matter (WDM). We have recently explored beam dynamics and possible beamline modifications required to simultaneously compress and accelerate the beam using a unipolar waveform. This has the advantage of a higher energy deposition in the target, and mimics beam manipulations in next-generation ion accelerators for WDM experiments. We report modeling and experimental results of this beam manipulation on the NDCX beamline with the new induction bunching module with approximately twice the volt-seconds.

  17. Neutral Evolution of Mutational Robustness

    CERN Document Server

    Van Nimwegen, E; Huynen, M; Nimwegen, Erik van; Crutchfield, James P.; Huynen, Martijn

    1999-01-01

    We introduce and analyze a general model of a population evolving over a network of selectively neutral genotypes. We show that the population's limit distribution on the neutral network is solely determined by the network topology and given by the principal eigenvector of the network's adjacency matrix. Moreover, the average number of neutral mutant neighbors per individual is given by the matrix spectral radius. This quantifies the extent to which populations evolve mutational robustness: the insensitivity of the phenotype to mutations. Since the average neutrality is independent of evolutionary parameters---such as, mutation rate, population size, and selective advantage---one can infer global statistics of neutral network topology using simple population data available from {\\it in vitro} or {\\it in vivo} evolution. Populations evolving on neutral networks of RNA secondary structures show excellent agreement with our theoretical predictions.

  18. Active beam spectroscopy for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Hellermann, M.G. von, E-mail: mgvh@jet.u [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Barnsley, R. [ITER Organization, 13108 St.-Paul-Lez-Durance, Cadarache (France); Biel, W. [Institut fuer Energieforschung, Plasmaphysik, Forschungszentrum Juelich, Euratom Association, 52425 Juelich (Germany); Delabie, E. [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Hawkes, N. [Culham Centre for Fusion Energy, Euratom Association, Culham OX14 3DB (United Kingdom); Jaspers, R. [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Johnson, D. [Princeton Plasma Physics Laboratory, Princeton, NJ-08548 (United States); Klinkhamer, F. [TNO Science and Industry, Stieltjesweg 1, 2628CK Delft (Netherlands); Lischtschenko, O. [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Marchuk, O. [Institut fuer Energieforschung, Plasmaphysik, Forschungszentrum Juelich, Euratom Association, 52425 Juelich (Germany); Schunke, B. [ITER Organization, 13108 St.-Paul-Lez-Durance, Cadarache (France); Singh, M.J. [Institute for Plasma Research, Bhat, Gandhinagar, Gurajat 384828 (India); Snijders, B. [TNO Science and Industry, Stieltjesweg 1, 2628CK Delft (Netherlands); Summers, H.P. [Culham Centre for Fusion Energy, Euratom Association, Culham OX14 3DB (United Kingdom); Thomas, D. [ITER Organization, 13108 St.-Paul-Lez-Durance, Cadarache (France); Tugarinov, S. [TRINITI Troitsk, Moscow Region 142092 (Russian Federation); Vasu, P. [Institute for Plasma Research, Bhat, Gandhinagar, Gurajat 384828 (India)

    2010-11-11

    Since the first feasibility studies of active beam spectroscopy on ITER in 1995 the proposed diagnostic has developed into a well advanced and mature system. Substantial progress has been achieved on the physics side including comprehensive performance studies based on an advanced predictive code, which simulates active and passive features of the expected spectral ranges. The simulation has enabled detailed specifications for an optimized instrumentation and has helped to specify suitable diagnostic neutral beam parameters. Four ITER partners share presently the task of developing a suite of ITER active beam diagnostics, which make use of the two 0.5 MeV/amu 18 MW heating neutral beams and a dedicated 0.1 MeV/amu, 3.6 MW diagnostic neutral beam. The IN ITER team is responsible for the DNB development and also for beam physics related aspects of the diagnostic. The RF will be responsible for edge CXRS system covering the outer region of the plasma (1>r/a>0.4) using an equatorial observation port, and the EU will develop the core CXRS system for the very core (0

  19. Simulations of space charge neutralization in a magnetized electron cooler

    Energy Technology Data Exchange (ETDEWEB)

    Gerity, James [Texas A-M; McIntyre, Peter M. [Texas A-M; Bruhwiler, David Leslie [RadiaSoft, Boulder; Hall, Christopher [RadiaSoft, Boulder; Moens, Vince Jan [Ecole Polytechnique, Lausanne; Park, Chong Shik [Fermilab; Stancari, Giulio [Fermilab

    2017-02-02

    Magnetized electron cooling at relativistic energies and Ampere scale current is essential to achieve the proposed ion luminosities in a future electron-ion collider (EIC). Neutralization of the space charge in such a cooler can significantly increase the magnetized dynamic friction and, hence, the cooling rate. The Warp framework is being used to simulate magnetized electron beam dynamics during and after the build-up of neutralizing ions, via ionization of residual gas in the cooler. The design follows previous experiments at Fermilab as a verification case. We also discuss the relevance to EIC designs.

  20. Neutral pion form factor measurement at NA62

    CERN Document Server

    Goudzovski, Evgueni

    2016-01-01

    The NA62 experiment at CERN collected a large sample of charged kaon decays with a highly efficient trigger for decays into electrons in 2007. The kaon beam represents a source of tagged neutral pion decays in vacuum. A measurement of the electromagnetic transition form factor slope of the neutral pion in the time-like region from $1.05\\times10^6$ fully reconstructed $\\pi^0$ Dalitz decay is presented. The limits on dark photon production in $\\pi^0$ decays from the earlier kaon experiment at CERN, NA48/2, are also reported.