WorldWideScience

Sample records for beam heating beams

  1. Beam induced heating

    CERN Document Server

    Salvant, B; Arduini, G; Assmann, R; Baglin, V; Barnes, M J; Baudrenghien, P; Bracco, C; Bruce, R; Bertarelli, A; Carra, F; Cattenoz, G; Caspers, F; Claudet, S; Day, H; Esteban Mueller, J; Gentini, L; Goddar, B; Grudiev, A; Henrist, B; Jones, R; Lanza, G; Lari, L; Mastoridis, T; Métral, E; Mounet, N; Nougaret, J L; Piguiet, A M; Redaelli, S; Roncarolo, F; Rumolo, G; Sapinski, M; Shaposhinkova, E; Tavian, L; Timmins, M; Uythoven, J; Vidal, A; Wollmann, D

    2012-01-01

    In 2011, the rapid increase of the luminosity performance of LHC came at the expense of increased temperature and pressure readings on several near-beam LHC equipments. In some cases, this beam induced heating was suspected to cause beam dumps and even degradation of the equipment. This contribution aims at gathering the observations of beam induced heating due to beam coupling impedance, their current level of understanding and possible actions that could be implemented during the winter stop 2011-2012.

  2. Plasma heating by a relativistic electron beam

    International Nuclear Information System (INIS)

    This thesis is devoted to the interaction of a Relativistic Electron Beam (REB) with a plasma. The goal of the experiment described herein is to study in detail the mechanism of energy transfer from the beam to the plasma. The beam particles have an energy of 800 keV, a current of 6 kA, a diameter of 3 cm and an adjustable pulse length of 50-150 ns. This beam is injected into cold hydrogen and helium plasmas with densities ranging from 1018 to 1020 m-3. First, the technical aspects of the experiment are described. Then measurements on the hf fields excited by the REB-plasma are presented (optical line profiles and spectra of beam electrons). The final section is devoted to plasma heating. (Auth.)

  3. Scaling studies of beam-heated tokamaks

    International Nuclear Information System (INIS)

    Parametric scaling of neutral beam-heated tokamaks is examined to determine the trade-off between beam energy and power. It is shown that over a wide range of plasma parameters and assumed transport properties, the center mean plasma temperature is a function of P/sub A/E/sub B//sup delta/, where E/sub B/ and P/sub A/ are the beam energy and power per unit area, respectively, and delta is a calculable constant of order unity

  4. Transmission of the Neutral Beam Heating Beams at TJ-II

    International Nuclear Information System (INIS)

    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

  5. Heat shrinkage of electron beam modified EVA

    Energy Technology Data Exchange (ETDEWEB)

    Datta, S.K.; Chaki, T.K.; Bhowmick, A.K. [Indian Institute of Technology, Kharagpur (India). Rubber Technology Center; Tikku, V.K.; Pradhan, N.K. [NICCO Corporation Ltd., (Cable Div.), Calcutta (India)

    1997-10-01

    Heat shrinkage of electron beam modified ethylene vinyl acetate copolymer (EVA) has been investigated over a range of times, temperatures, stretching, irradiation doses and trimethylolpropane trimethacrylate (TMPTMA) levels. The irradiated (radiation dose 50 kGy and TMPTMA level 1%) and stretched (100% elongation) sample shrinks to a maximum level when kept at 453K temperature for 60 s. The heat shrinkage of samples irradiated with radiation doses of 20, 50, 100 and 150 kGy increases sharply with increasing stretching in the initial stage. Amnesia rating decreases with increasing radiation dose and TMPTMA level as well as gel content. The high radiation dose and TMPTMA level lower the heat shrinkage due to the chain scission. The effect of temperature at which extension is carried out on heat shrinkage is marginal. The irradiated (radiation dose 50 kGy and TMPTMA level 1%) EVA tubes of different dimensions expanded in a laboratory grade tube expander show similar behaviour at 453K and 60 s. The X-ray and DSC studies reveal that the crystallinity increases on stretching due to orientation of chains and it decreases to a considerable extent on heat shrinking. The theoretical and experimental values of heat shrinkage for tubes and rectangular strips are in good accord, when the radiation dose is 50 kGy and TMPTMA level 1%. (author).

  6. Update on Beam Induced RF Heating in the LHC

    CERN Document Server

    Salvant, B; Arduini, G; Assmann, R; Baglin, V; Barnes, M; Bartmann, W; Baudrenghien, P; Berrig, O; Bracco, C; Bravin, E; Bregliozzi, G; Bruce, R; Bertarelli, A; Carra, F; Cattenoz, G; Caspers, F; Claudet, S; Day, H; Garlasche, M; Gentini, L; Goddard, B; Grudiev, A; Henrist, B; Jones, R; Kononenko, O; Lanza, G; Lari, L; Mastoridis, T; Mertens, V; Métral, E; Mounet, N; Muller, J; Nosych, A; Nougaret, J; Persichelli, S; Piguiet, A; Redaelli, S; Roncarolo, F; Rumolo, G; Salvachua, B; Sapinski, M; Schmidt, R; Shaposhnikova, E; Tavian, L; Timmins, M; Uythoven, J; Vidal, A; Wenninger, J; Wollmann, D; Zerlauth, M; Fassnacht, P; Jakobsen, S; Deile, M

    2013-01-01

    Since June 2011 the rapid increase of the luminosity performance of the LHC has come at the expense of both increased temperature and pressure of specific, near-beam, LHC equipment. In some cases, this beam induced heating has caused delays while equipment cool-down, beam dumps and even degradation of some devices. This contribution gathers the observations of beam induced heating, attributed to longitudinal beam coupling impedance, their current level of understanding and possible actions planned to be implemented during the 1st LHC Long Shutdown (LS1) in 2013-2014.

  7. Studies of beam heating of proton beam profile monitor SEM's

    Energy Technology Data Exchange (ETDEWEB)

    Pavlovich, Zarko; Osiecki, Thomas H.; Kopp, Sacha E.; /Texas U.

    2005-05-01

    The authors present calculations of the expected temperature rise of proton beam profile monitors due to beam heating. The profile monitors are secondary emission monitors (SEM's) to be made of Titanium foils. The heating is studied to understand whether there is any loss of tension or alignment of such devices. Additionally, calculations of thermally-induced dynamic stress are presented. Ti foil is compared to other materials and also to wire SEM's. The calculations were initially performed for the NuMI beam, where the per-pulse intensity is quite high; for completeness the calculations are also performed for other beam energies and intensities.

  8. Beam-Beam Effects

    CERN Document Server

    Herr, W

    2014-01-01

    One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description of the phenomena that are present in modern colliding beam facilities.

  9. 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.

  10. Hydrodynamic Expansion of Pellicles Caused by e-Beam Heating

    CERN Document Server

    Ho, D

    2000-01-01

    Placing a pellicle in front of a x-ray converter target for radiographic applications can confine the backstreaming ions and target plasma to a shorter channel so that the cumulative effect on e-beam focusing is reduced. The pellicle is subject to heating by e-beam since the pellicle is placed upstream of the target. The calculation of the hydrodynamic expansion, caused by the heating, using the radiation hydrodynamics code LASNEX is presented in this report. Calculations show that mylar pellicles disintegrate at the end of a multi-pulse intense e-beam while beryllium and carbon pellicles remain intact. The expansions for the kapton-carbon multi-layered targets are also examined. Hydrodynamic expansions for pellicles with various e-beam spot radii are calculated for DARHT-II beam parameters. All the simulation results indicate that the backstreaming ions can be stopped.

  11. Commissioning of heating neutral beams for COMPASS-D tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Deichuli, P.; Davydenko, V.; Belov, V.; Gorbovsky, A.; Dranichnikov, A.; Ivanov, A.; Sorokin, A.; Mishagin, V.; Abdrashitov, A.; Kolmogorov, V.; Kondakov, A. [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation)

    2012-02-15

    Two neutral beam injectors have been developed for plasma heating on COMPASS-D tokamak (Institute of Plasma Physics, Prague). The 4-electrodes multihole ion-optical system with beam focusing was chosen to provide the low divergence 300 kW power in both deuterium and hydrogen atoms. The accelerating voltage is 40 kV at extracted ion current up to 15 A. The power supply system provides the continuous and modulated mode of the beam injection at a maximal pulse length 300 ms. The optimal arrangement of the cryopanels and the beam duct elements provides sufficiently short-length beamline which reduces the beam losses. The evolution of the impurities and molecular fraction content is studied in the process of the high voltage conditioning of the newly made ion sources. Two injectors of the same type have been successfully tested and are ready for operation at tokamak in IPP, Prague.

  12. "Twisted Beam" SEE Observations of Ionospheric Heating from HAARP

    Science.gov (United States)

    Briczinski, S. J.; Bernhardt, P. A.; Siefring, C. L.; Han, S.-M.; Pedersen, T. R.; Scales, W. A.

    2015-10-01

    Nonlinear interactions of high power HF radio waves in the ionosphere provide aeronomers with a unique space-based laboratory capability. The High-Frequency Active Auroral Research Program (HAARP) in Gakona, Alaska is the world's largest heating facility, yielding effective radiated powers in the gigawatt range. New results are present from HAARP experiments using a "twisted beam" excitation mode. Analysis of twisted beam heating shows that the SEE results obtained are identical to more traditional patterns. One difference in the twisted beam mode is the heating region produced is in the shape of a ring as opposed to the more traditional "solid spot" region from a pencil beam. The ring heating pattern may be more conducive to the creation of stable artificial airglow layers because of the horizontal structure of the ring. The results of these runs include artificial layer creation and evolution as pertaining to the twisted beam pattern. The SEE measurements aid the interpretation of the twisted beam interactions in the ionosphere.

  13. Electron beam welding of heat exchangers

    International Nuclear Information System (INIS)

    For a long time neither qualitative, nor quantitative criteria have been available that would have allowed choosing the most suitable welding techniques from the three stated below: 1) electron gun rotates relative to stationary tube; 2) electron beam is magnetically deviated relative to stationary tube; 3) permanent deviation magnet is rotated mechanically relative to stationary tube and gun. To our experience, the 2nd technique is most promising when welding 16x1.5 diameter stainless tubes. The e-b welds are vulnerable to root defects. With welding done in a movable manner, the root defect area will be found to locate in the tube plate body and, hence, the weldment, as a whole, will not be impaired

  14. Wave heating of an ion beam in a tokamak plasma

    International Nuclear Information System (INIS)

    Heating of a 26-keV trapped-ion beam by interaction with incident lower-hybrid RF power (as low as 5kW) was observed in the ATC plasma. We suggest that ion-cyclotron damping of lower hybrid waves by beam ions can account for the increase in beam energy. This process can explain the main features of the experiment: (1) preferential absorption in the perpendicular direction, (2) lack of absorption by the background plasma ions, and (3) low power requirement for absorption. Theory requires ksub(perpendicular)rhosub(i) approximately > (ω/ωsub(ci))sup(1/2). The relatively high perpendicular temperature of the beam ions (approximately 1keV), combined with one of several possibilities for RF energy at large ksub(perpendicular), allows the condition on ksub(perpendicular)rhosub(i) to be satisfied. Moreover, the large parallel energy of the beam ions plays a major role in broadening the harmonic resonances, thus making it possible for a large number of beam ions to resonate with the wave. Though the primary process is perpendicular absorption, there is also a net gain in parallel energy during a collision time due to pitch-angle scattering. The importance of this heating mechanism for large machines such as TFTR is discussed. For these machines, ions will be injected with large rhosub(i), making ion heating possible even with moderate values of ksub(perpendicular). (author)

  15. Beam-beam effects

    Energy Technology Data Exchange (ETDEWEB)

    Zholents, A.

    1994-12-01

    The term beam-beam effects is usually used to designate different phenomena associated with interactions of counter-rotating beams in storage rings. Typically, the authors speak about beam-beam effects when such interactions lead to an increase of the beam core size or to a reduction of the beam lifetime or to a growth of particle`s population in the beam halo and a correspondent increase of the background. Although observations of beam-beam effects are very similar in most storage rings, it is very likely that every particular case is largely unique and machine-dependent. This constitutes one of the problems in studying the beam-beam effects, because the experimental results are often obtained without characterizing a machine at the time of the experiment. Such machine parameters as a dynamic aperture, tune dependencies on amplitude of particle oscillations and energy, betatron phase advance between the interaction points and some others are not well known, thus making later analysis uncertain. The authors begin their discussion with demonstrations that beam-beam effects are closely related to non linear resonances. Then, they will show that a non linearity of the space charge field is responsible for the excitation of these resonances. After that, they will consider how beam-beam effects could be intensified by machine imperfections. Then, they will discuss a leading mechanism for the formation of the beam halo and will describe a new technique for beam tails and lifetime simulations. They will finish with a brief discussion of the coherent beam-beam effects.

  16. HEAT-RESISTANT COMPOSITES CURED BY ELECTRON BEAM

    Institute of Scientific and Technical Information of China (English)

    Jian-wen Bao; Yang Li; Xiang-bao Chen; Feng-mei Li

    2001-01-01

    Electron beam (EB) curing of composites has many advantages. Heat-resistant EB-curing composites could substitute polyimide composites used in aeronautical engines. In this paper, the effects of catalyst and dose on the cured resin were investigated. The heat-resistance of the resin cured by EB was evaluated by dynamic mechanical analysis (DMA). The experimental results show that the mechanical properties of the composites cured by EB could meet the specifications of aeronautical engines at 250°C.

  17. Beam Heating of Samples: Modeling and Verification. Part 2

    Science.gov (United States)

    Kazmierczak, Michael; Gopalakrishnan, Pradeep; Kumar, Raghav; Banerjee Rupak; Snell, Edward; Bellamy, Henry; Rosenbaum, Gerd; vanderWoerd, Mark

    2006-01-01

    Energy absorbed from the X-ray beam by the sample requires cooling by forced convection (i.e. cryostream) to minimize temperature increase and the damage caused to the sample by the X-ray heating. In this presentation we will first review the current theoretical models and recent studies in the literature, which predict the sample temperature rise for a given set of beam parameters. It should be noted that a common weakness of these previous studies is that none of them provide actual experimental confirmation. This situation is now remedied in our investigation where the problem of x-ray sample heating is taken up once more. We have theoretically investigated, and at the same time, in addition to the numerical computations, performed experiments to validate the predictions. We have modeled, analyzed and experimentally tested the temperature rise of a 1 mm diameter glass sphere (sample surrogate) exposed to an intense synchrotron X-ray beam, while it is being cooled in a uniform flow of nitrogen gas. The heat transfer, including external convection and internal heat conduction was theoretically modeled using CFD to predict the temperature variation in the sphere during cooling and while it was subjected to an undulator (ID sector 19) X-ray beam at the APS. The surface temperature of the sphere during the X-ray beam heating was measured using the infrared camera measurement technique described in a previous talk. The temperatures from the numerical predictions and experimental measurements are compared and discussed. Additional results are reported for the two different sphere sizes and for two different supporting pin orientations.

  18. Response of optical hydrogen lines to beam heating: I. Electron beams

    CERN Document Server

    Kasparova, J; Heinzel, P; Karlicky, M; Moravec, Z

    2009-01-01

    We investigate the role of non-thermal electrons in the formation regions of Halpha, Hbeta, and Hgamma lines in order to unfold their influence on the formation of these lines. We concentrate on pulse-beam heating varying on a subsecond timescale. Furthermore, we theoretically explore possibility that a new diagnostic tool exists indicating the presence of non-thermal electrons in the flaring chromosphere based on observations of optical hydrogen lines. To model the evolution of the flaring atmosphere and the time-dependent hydrogen excitation and ionisation, we used a 1-D radiative hydrodynamic code combined with a test-particle code that simulates the propagation, scattering, and thermalisation of a power-law electron beam in order to obtain the flare heating and the non-thermal collisional rates due to the interaction of the beam with the hydrogen atoms. All calculated models have shown a time-correlated response of the modelled Balmer line intensities on a subsecond timescale, with a subsecond timelag beh...

  19. Comparative study of beam losses and heat loads reduction methods in MITICA beam source

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, E., E-mail: emanuele.sartori@igi.cnr.it; Agostinetti, P.; Dal Bello, S.; Marcuzzi, D.; Serianni, G.; Veltri, P. [Consorzio RFX, Euratom-ENEA association, C.so Stati Uniti 4, 35127 Padova (Italy); Sonato, P. [Consorzio RFX, Euratom-ENEA association, C.so Stati Uniti 4, 35127 Padova (Italy); Dipartimento di Ingegneria Elettrica, Padova University, Via Gradenigo 6/a, 35131 Padova (Italy)

    2014-02-15

    In negative ion electrostatic accelerators a considerable fraction of extracted ions is lost by collision processes causing efficiency loss and heat deposition over the components. Stripping is proportional to the local density of gas, which is steadily injected in the plasma source; its pumping from the extraction and acceleration stages is a key functionality for the prototype of the ITER Neutral Beam Injector, and it can be simulated with the 3D code AVOCADO. Different geometric solutions were tested aiming at the reduction of the gas density. The parameter space considered is limited by constraints given by optics, aiming, voltage holding, beam uniformity, and mechanical feasibility. The guidelines of the optimization process are presented together with the proposed solutions and the results of numerical simulations.

  20. Plasma Heating and Burnout in Beam-Plasma Interaction

    International Nuclear Information System (INIS)

    Experiments using beam-plasma interaction to generate fully ionized plasma and enhance the temperature of the components are in progress at Oak Ridge National Laboratory. Previous experimental work demonstrated that an electron beam of 5 keV could heat plasma electrons in a magnetic mirror machine to a temperature over 100 keV. In this extension of the earlier work the electron beam is directed through higher pressure gas. Such a dense cloud of electrons is produced that neutral gas streaming inward from the walls is almost completely ionized or burned out before reaching the center of the apparatus. The most spectacular feature of the burnout transition is the sudden decrease of spectral light by a factor about 1000. Several neutral beam transmission experiments give electron densities greater than 1012 cm-3. Microwave cut-off measurements agree with this lower limit. Direct measurements of the electron plasma frequency and the ion plasma frequency give a density of 5 x 1012 cm-3. Once the neutral gas in the plasma is ionized, the electron cooling by excitation processes and the ion cooling by charge-exchange phenomena disappear; therefore, any electron and ion heating caused by the electron beam should have time to take effect. Pin-hole camera images formed by 50-keV X-rays give evidence of electron heating. Ion heating is limited by wall proximity to 20-keV deuterons in the Burnout IV device and 200-keV deuterons in the larger Burnout V device. Magnetic and electrostatic analysis give evidence for the existence of some deuterons at 20 keV in Burnout IV; similar analysis is in progress on Burnout V. In Burnout V the electron beam traverses the central 300 cm3 of the 10-liter volume between the mirrors of a 40-20-40-kG mirror machine. Injection and multiple reflection of the 45-kW electron beam occur outside the mirrors in a region of 10-5 Torr ambient pressure. The lifetime of the plasma is difficult both to measure and to predict on theoretical grounds. The

  1. Beam screen regenerative heating cryogenic impact and feasibility

    CERN Document Server

    Tavian, Laurent

    2003-01-01

    Desorbtion of gas (H2, CO, CO2...) trapped on the beam screen wall is envisaged by regenerative heating to temperature varying between 40 K and 90 K depending on the gas species. This new requirement has direct consequences on the cold mass heat loads, on the heating capacity needed to reach the regeneration conditions, as well as on the heater and piping configuration. This note presents different configuration schemes, studies the cryogenic feasibility with existing limitations and gives the impact on the cryogenic system in terms of additional equipment and corresponding extra costs.

  2. Substrate heating measurements in pulsed ion beam film deposition

    Energy Technology Data Exchange (ETDEWEB)

    Olson, J.C.; Davis, H.A.; Rej, D.J.; Waganaar, W.J. [Los Alamos National Lab., NM (United States); Tallant, D.R. [Cornell Univ., Ithaca, NY (United States). Materials Science and Engineering Dept.; Thompson, M.O. [Sandia National Labs., Albuquerque, NM (United States)

    1995-05-01

    Diamond-like Carbon (DLC) films have been deposited at Los Alamos National Laboratory by pulsed ion beam ablation of graphite targets. The targets were illuminated by an intense beam of hydrogen, carbon, and oxygen ions at a fluence of 15-45 J/cm{sup 2}. Ion energies were on the order of 350 keV, with beam current rising to 35 kA over a 400 ns ion current pulse. Raman spectra of the deposited films indicate an increasing ratio of sp{sup 3} to sp{sup 2} bonding as the substrate is moved further away from the target and further off the target normal. Using a thin film platinum resistor at varying positions, we have measured the heating of the substrate surface due to the kinetic energy and heat of condensation of the ablated material. This information is used to determine if substrate heating is responsible for the lack of DLC in positions close to the target and near the target normal. Latest data and analysis will be presented.

  3. Lower hybrid wave heating into neutral beam heated plasma in the JT-60 tokamak

    International Nuclear Information System (INIS)

    Injection of high-power lower hybrid waves (LHW) of up to 6.0 MW into neutral-beam-20 MW-heated plasmas with the medium electron density regime (n-bare ≤ 3.5 x 1019 m-3) increases the plasma energy content at the same incremental energy confinement time as in the case of neutral beam heating alone. In addition to thermal electron and ion heating, LHW accelerates beam ions to energies considerably higher than the beam injection energy. In contrast to LH injection into OH plasmas in the same density regime, where substantial high-energy electron production is observed, the case of combined heating shows much less high-energy electrons. The heating efficiency of LHW in the combined heating case tends to decrease as the electron density is increased. Ray-tracing analysis suggests that the accessibility condition prevents effective heating in a high-density plasma. Estimation of wave damping, which is taking account of the beam component of the ion velocity distribution function, indicates that waves are absorbed by beam ions before they are absorbed by electrons. (author)

  4. Focused neutral beams with low chaotic divergence for plasma heating and diagnostics in magnetic fusion devices

    International Nuclear Information System (INIS)

    A series of neutral beam injectors has been developed in the Budker Institute of Nuclear Physics for plasma heating and diagnostics in modern fusion devices. Ion optical system of these injectors is optimized to produce ion beams with low angular divergence. In order to provide beam focusing, the grids are formed to be spherical segments. Such geometrically focused neutral beams are particularly advantageous for plasma diagnostics when high spatial resolution is required. Another application of these beams is plasma heating in the machines with narrow ports through which only small size, high power density beams can be transported. (author)

  5. Investigation of heat release in the targets during irradiation by ion beams

    CERN Document Server

    Dalkarov, O D; Rusetskii, A S

    2015-01-01

    The DD-reaction is investigated and the heat emission off the targets during their irradiation with ion beams is studied at the HELIS ion accelerator at LPI. The heat emission is observed to be significantly higher in the case of irradiation of the Ti/TiO2:Dx-targets by a D+ beam, as compared to the H+ and Ne+ beams. Furthermore, it depends on the concentration of deuterium in the target and current density of the deuteron beam.

  6. Numerical Simulation of the Self-Heating Effect Induced by Electron Beam Plasma in Atmosphere

    Institute of Scientific and Technical Information of China (English)

    邓永锋; 谭畅; 韩先伟; 谭永华

    2012-01-01

    For exploiting advantages of electron beam air plasma in some unusual applications, a Monte Carlo (MC) model coupled with heat transfer model is established to simulate the characteristics of electron beam air plasma by considering the self-heating effect. Based on the model, the electron beam induced temperature field and the related plasma properties are investigated. The results indicate that a nonuniform temperature field is formed in the electron beam plasma region and the average temperature is of the order of 600 K. Moreover, much larger volume pear-shaped electron beam plasma is produced in hot state rather than in cold state. The beam ranges can, with beam energies of 75 keV and 80 keV, exceed 1.0 m and 1.2 m in air at pressure of 100 torr, respectively. Finally, a well verified formula is obtained for calculating the range of high energy electron beam in atmosphere.

  7. Beam heat load measurements in the cold bore superconductive undulator in ANKA

    CERN Document Server

    Casalbuoni, S; Hagelstein, M; Zimmermann, F; Rossmanith, Robert; Kostka, Barbara; Mashkina, Elena; Steffens, Erhard; Bernhard, Axel; Wollmann, Daniel; Baumbach, Tilo

    2007-01-01

    Measurements of the beam-induced heat load in the ANKA cold-bore superconductive undulator are summarized. The strength of the two dominating effects, resistive wall heating and heating by electron bombardment, depends on the beam parameters and the gap width.

  8. Bessel Beams

    OpenAIRE

    McDonald, Kirk T

    2000-01-01

    Scalar Bessel beams are derived both via the wave equation and via diffraction theory. While such beams have a group velocity that exceeds the speed of light, this is a manifestation of the "scissors paradox" of special relativty. The signal velocity of a modulated Bessel beam is less than the speed of light. Forms of Bessel beams that satisfy Maxwell's equations are also given.

  9. High Power Hydrogen Injector with Beam Focusing for Plasma Heating

    International Nuclear Information System (INIS)

    High power neutral beam injector has been developed with the atom energy of 25 keV, a current of 60 A, and several milliseconds pulse duration. Six of these injectors will be used for upgrade of the atomic injection system at central cell of a Gas Dynamic Trap (GDT) device and 2 injectors are planned for SHIP experiment.The injector ion source is based on an arc discharge plasma box. The plasma emitter is produced by a 1 kA arc discharge in hydrogen. A multipole magnetic field produced with permanent magnets at the periphery of the plasma box is used to increase its efficiency and improve homogeneity of the plasma emitter. The ion beam is extracted by a 4-electrodes ion optical system (IOS). Initial beam diameter is 200 mm. The grids of the IOS have a spherical curvature for geometrical focusing of the beam. The optimal IOS geometry and grid potentials were found with the numerical simulation to provide precise beam formation. The measured angular divergence of the beam is 0.02 rad, which corresponds to the 2.5 cm Gaussian radius of the beam profile measured at focal point

  10. 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.

  11. 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. PMID:26628137

  12. Electron beam heating of a semi-infinite solid

    International Nuclear Information System (INIS)

    Techniques are described for calculating the temperature rise in a semi-infinite solid caused by any cylindrically symmetric electron beam incident on its surface. The temperature rise at any point and time can be expressed as two dimensional integral, but this cannot be evaluated conveniently by numerical methods because of singularities. A mixed numerical plus analytical method has therefore been developed. For the special case of a 'hollow' electron beam consisting of a line of Gaussian sources uniformly distributed along a circle further simplification is possible, to a one dimensional integral which can be evaluated by simple numerical methods. Results are presented for this 'hollow' electron beam and for a beam with uniform current density. (author)

  13. Resistive wall heating due to image current on the beam chamber for a superconducting undulator.

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. H. (Accelerator Systems Division (APS))

    2012-03-27

    The image-current heating on the resistive beam chamber of a superconducting undulator (SCU) was calculated based on the normal and anomalous skin effects. Using the bulk resistivity of copper for the beam chamber, the heat loads were calculated for the residual resistivity ratios (RRRs) of unity at room temperature to 100 K at a cryogenic temperature as the reference. Then, using the resistivity of the specific aluminum alloy 6053-T5, which will be used for the SCU beam chamber, the heat loads were calculated. An electron beam stored in a storage ring induces an image current on the inner conducting wall, mainly within a skin depth, of the beam chamber. The image current, with opposite charge to the electron beam, travels along the chamber wall in the same direction as the electron beam. The average current in the storage ring consists of a number of bunches. When the pattern of the bunched beam is repeated according to the rf frequency, the beam current may be expressed in terms of a Fourier series. The time structure of the image current is assumed to be the same as that of the beam current. For a given resistivity of the chamber inner wall, the application ofthe normal or anomalous skin effect will depend on the harmonic numbers of the Fourier series of the beam current and the temperature of the chamber. For a round beam chamber with a ratius r, much larger than the beam size, one can assume that the image current density as well as the density square, may be uniform around the perimeter 2{pi}r. For the SCU beam chamber, which has a relatively narrow vertical gap compared to the width, the effective perimeter was estimated since the heat load should be proportional to the inverse of the perimeter.

  14. Steerable beam systems for electron cyclotron resonance heating

    International Nuclear Information System (INIS)

    Several methods are discussed for steering a 200 kW pencil beam of electromagnetic waves in the 60 GHz to 200 GHz frequency range. These include methods incorporating swivelling mirrors, phased arrays, mode converters, and optical materials. It is found that for the near term, the mechanical systems are best, capable of steering times of 3 ms to 100 ms and losses of less than 5%. Optical methods, as yet virtually uninvestigated, appear to offer the only means of beam-steering in the 5μs to 100μs range necessary for MHD mode tracking

  15. Spectroscopic study of impurities in neutral beam heated and ohmically heated JT-60 discharges

    International Nuclear Information System (INIS)

    Impurities in JT-60 were studied by visible and VUV spectroscopy over two periods of operation. The two periods wree distinguished by the use of different first wall materials: from April 1985 to March 1987, TiC coated molybdenum was used as limiter material; from June to October 1987, graphite was used. Quantitative spectroscopic measurements of Zeff, impurity concentrations and radiated power losses were made for ohmically heated and neutral beam heated discharges with limiter and divertor configurations. In the first phase with metallic first wall material, oxygen, carbon and titanium were identified as the main plasma impurities. In neutral beam heated, diverted discharges, Zeff was 1.6 at n-bare=4x1019m-3. The concentrations of oxygen, carbon and titanium were 1%, 0.1% and 0.006% of ne, respectively. In the second phase with graphite material, the metallic impurities were reduced, and the contribution of metallic impurities to the radiated power loss was less than 1%. However, Zeff increased up to 3 in neutral beam heated discharges. In limited plasmas, the concentrations of oxygen and carbon were 1% and 5%, respectively, at n-bare=4x1019m-3, in diverted plasmas, these concentrations were 2% and 0.4% at the same n-bare. The radiated power loss from the main plasma was 20-40% of the input power in neutral beam heated, limited discharges, and 7-25% in diverted discharges. The contributions of oxygen and carbon to the radiated power in limited discharges were comparable, and in diverted discharges the contribution of oxygen was dominant. (author). 29 refs, 15 figs, 2 tabs

  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. Temporal structure of double plasma frequency emission of thin beam-heated plasma

    Energy Technology Data Exchange (ETDEWEB)

    Postupaev, V. V.; Ivanov, I. A.; Arzhannikov, A. V.; Vyacheslavov, L. N. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 2 Pirogova st., 630090 Novosibirsk (Russian Federation); Burdakov, A. V.; Polosatkin, S. V. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 20 Karl Marks Avenue, 630092 Novosibirsk (Russian Federation); Sklyarov, V. F.; Gavrilenko, D. Ye.; Kandaurov, I. V.; Kurkuchekov, V. V.; Mekler, K. I.; Popov, S. S.; Rovenskikh, A. F.; Sudnikov, A. V.; Sulyaev, Yu. S.; Trunev, Yu. A. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, 630090 Novosibirsk (Russian Federation); Kasatov, A. A. [Novosibirsk State University, 2 Pirogova st., 630090 Novosibirsk (Russian Federation)

    2013-09-15

    In the work presented here dynamics of spiky microwave emission of a beam-heated plasma near the double plasma frequency in ∼100 GHz band was studied. The plasma is heated by 80 keV, ∼2 MW, sub-ms electron beam that is injected into the multiple-mirror trap GOL-3. The beam-heated plasma diameter is of the order of the emitted wavelength. Modulation of individual emission spikes in the microwave radiation is found. The radiation dynamics observed can be attributed to a small number of compact emitting zones that are periodically distorted.

  18. Beam - cavity interaction beam loading

    International Nuclear Information System (INIS)

    The interaction of a beam with a cavity and a generator in cyclic accelerators or storage rings is investigated. Application of Maxwell's equations together with the nonuniform boundary condition allows one to get an equivalent circuit for a beam-loaded cavity. The general equation for beam loading is obtained on the basis of the equivalent circuit, and the beam admittance is calculated. Formulas for power consumption by a beam-loaded cavity are derived, and the optimal tuning and coupling factor are analyzed. (author)

  19. Neoclassical current effects in neutral-beam-heated tokamak discharges

    International Nuclear Information System (INIS)

    There is a long-standing prediction from neoclassical theory that strong contributions to the toroidal current should be driven by friction between trapped and passing particles when βsub(pol) exceeds root (R/a) in a tokamak. A number of neutral-beam heating experiments can now produce such parameters, and it is of interest to calculate the behaviour which should occur in this regime to determine the feasibility of using such a 'bootstrap' current as a steady-state tokamak current source. It is found that the neoclassical current should be large enough to reverse the external loop voltage for typical experimental parameters (ISX-B, in particular) in cases where the total current is fixed and to produce a detectable excess of total current above the pre-programmed (demand) value in cases where the loop voltage is regulated. Other manifestations of such a current should be either: a sharp rise in the central q-value (producing a cessation of internal m=1 and m=2 MHD activity), with an enhancement by two orders of magnitude of ion thermal conductivity (due to the formation of a hollow current density profile and a consequent drop in local values of the poloidal magnetic field in the central plasma region), or an enhanced tendency for disruption (arising from magnetic reconnection in hollow-profile equilibria). Since these gross manifestations are absent in a wide range of experiments on the Impurity Study Experiment (ISX-B), as reported earlier, the conclusion is that the neoclassical current, if present, can have a value no larger than 25% of its theoretically calculated value. Since the neoclassical particle (Ware) pinch is strongly related to the neoclassical current in the theory (Onsager reciprocity), the existence of the particle pinch is thus called into question. (author)

  20. Chilled beam application guidebook

    CERN Document Server

    Butler, David; Gräslund, Jonas; Hogeling, Jaap; Lund Kristiansen, Erik; Reinikanen, Mika; Svensson, Gunnar

    2007-01-01

    Chilled beam systems are primarily used for cooling and ventilation in spaces, which appreciate good indoor environmental quality and individual space control. Active chilled beams are connected to the ventilation ductwork, high temperature cold water, and when desired, low temperature hot water system. Primary air supply induces room air to be recirculated through the heat exchanger of the chilled beam. In order to cool or heat the room either cold or warm water is cycled through the heat exchanger.

  1. Efficient Heating of Thin Cylindrical Targets by Broad Electromagnetic Beams I

    OpenAIRE

    Akhmeteli, Andrey

    2004-01-01

    In many high-profile applications, such as nuclear fusion and pumping of active media of short-wavelength lasers, it is necessary to achieve high specific input of power of an electromagnetic beam in a target. Diffraction sets the lower limit to the transverse dimensions of electromagnetic beams and represents a fundamental obstacle for electromagnetic heating of small or inaccessible regions. It was found, however, that it is possible to achieve efficient heating of cylindrical targets by el...

  2. Beam loading

    CERN Document Server

    Gamp, Alexander

    2013-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  3. Transport of laser accelerated proton beams and isochoric heating of matter

    International Nuclear Information System (INIS)

    The acceleration of intense proton and ion beams by ultra-intense lasers has matured to a point where applications in basic research and technology are being developed. Crucial for harvesting the unmatched beam parameters driven by the relativistic electron sheath is the precise control of the beam. We report on recent experiments using the PHELIX laser at GSI, the VULCAN laser at RAL and the TRIDENT laser at LANL to control and use laser accelerated proton beams for applications in high energy density research. We demonstrate efficient collimation of the proton beam using high field pulsed solenoid magnets, a prerequisite to capture and transport the beam for applications. Furthermore we report on two campaigns to use intense, short proton bunches to isochorically heat solid targets up to the warm dense matter state. The temporal profile of the proton beam allows for rapid heating of the target, much faster than the hydrodynamic response time thereby creating a strongly coupled plasma at solid density. The target parameters are then probed by X-ray Thomson scattering (XRTS) to reveal the density and temperature of the heated volume. This combination of two powerful techniques developed during the past few years allows for the generation and investigation of macroscopic samples of matter in states present in giant planets or the interior of the earth.

  4. Performance Test of High Heat Flux Test Facility for the Calorimetry and Beam Control

    International Nuclear Information System (INIS)

    The Korea Heat Load Test facility, KoHLT-EB (Electron Beam) has been operating for the plasma facing components to develop fusion engineering in Korea. The ITER Neutral Beam Duct Liner (NBDL) was fabricated and tested to qualify the thermocouple fixation method for the temperature measurement during a direct collision of the high-power neutral beam during ITER operation. The NBDL is CuCrZr panels, which are actively water cooled using deep drilled channels. To perform the profile test, the assessment for the possibility of an electron beam Gaussian power density profile and the result of absorbed power for that profile before the test start is needed. To assess the possibility of Gaussian profile, for the qualification test of a Gaussian heat load profile, small calorimetry was manufactured to simulate a real heat profile in the neutral beam duct liner, and this calorimetry has two cooling channel with five thermocouples, which is the same as NBDL. Preliminary analyses with ANSYSCFX using a 3D model were performed with the calorimetry model. The heating area was modeled to be 60 mm x 250 mm. The simulated heat flux is 0.5 - 1.2 MW/m''2 at 0.75 kg/sec of the water flow rate. A steady heat flux test was performed to measure the surface heat flux, surface temperature profile. With a thermohydraulic analysis and heat load test, the Gaussian heat profile will be confirmed for this calorimetry and NBDL mockup. The Korean heat load test facility will be used to qualify the specifications of various plasma facing components in fusion devices. To conduct a beam profile test, an assessment of the possibility of electron beam Gaussian power density profile and the results of the absorbed power for that profile before the test starts are needed. To assess the possibility of a Gaussian profile, for the qualification test of the Gaussian heat load profile, a calorimeter mockup and large Cu module were manufactured to simulate real heat. For this high-heat flux test

  5. Beam Instabilities

    CERN Document Server

    Rumolo, G

    2014-01-01

    When a beam propagates in an accelerator, it interacts with both the external fields and the self-generated electromagnetic fields. If the latter are strong enough, the interplay between them and a perturbation in the beam distribution function can lead to an enhancement of the initial perturbation, resulting in what we call a beam instability. This unstable motion can be controlled with a feedback system, if available, or it grows, causing beam degradation and loss. Beam instabilities in particle accelerators have been studied and analysed in detail since the late 1950s. The subject owes its relevance to the fact that the onset of instabilities usually determines the performance of an accelerator. Understanding and suppressing the underlying sources and mechanisms is therefore the key to overcoming intensity limitations, thereby pushing forward the performance reach of a machine.

  6. Two-Pipe Chilled Beam System for Both Cooling and Heating of Office Buildings

    DEFF Research Database (Denmark)

    Afshari, Alireza; Gordnorouzi, Rouzbeh; Hultmark, Göran;

    2013-01-01

    . The building model had a net volume of 3669 m3, (L*B: 25.5m*11.5 m) and net ceiling height of 2.55 m. The building model was assumed to consist of 78 office rooms, 6 meeting rooms and 5 corridors with a 50% occupancy. Simulations were executed using Bsim, an energy simulation program, to calculate the energy...... advantage of renewable energy. The results showed that the energy consumption was 3% less in the 2-pipe chilled beam system in comparison with the conventional 4-pipe system when moving cooled and heated water through the building, transferring the energy to where it is needed. Using free cooling (taking......Simulations were performed to compare a conventional 4-pipe chilled beam system and a 2-pipe chilled beam system. The objective was to establish requirements, possibilities and limitations for a well-functioning 2-pipe chilled beam system for both cooling and heating of office buildings...

  7. Two-Pipe Chilled Beam System for Both Cooling and Heating of Office Buildings

    OpenAIRE

    Afshari, Alireza; Gordnorouzi, Rouzbeh; Hultmark, Göran; Bergsøe, Niels Christian

    2013-01-01

    Simulations were performed to compare a conventional 4-pipe chilled beam system and a 2-pipe chilled beam system. The objective was to establish requirements, possibilities and limitations for a well-functioning 2-pipe chilled beam system for both cooling and heating of office buildings. The building model had a net volume of 3669 m3, (L*B: 25.5m*11.5 m) and net ceiling height of 2.55 m. The building model was assumed to consist of 78 office rooms, 6 meeting rooms and 5 corridors with a 50% o...

  8. Collective Thomson scattering of a high power electron cyclotron resonance heating beam in LHD

    DEFF Research Database (Denmark)

    Kubo, S.; Nishiura, M.; Tanaka, K.;

    2010-01-01

    Collective Thomson scattering (CTS) system has been constructed at LHD making use of the high power ECRH system in LHD. The necessary features for CTS, high power probing beams and receiving beams, both with well defined Gaussian profile and with the fine controllability, are endowed in the ECRH ...... and applied to derive the bulk and high energy ion components for several combinations of NBI heated plasmas....

  9. Non-Fourier Heat Conduction Effects During High-Energy Beam Metalworking

    Institute of Scientific and Technical Information of China (English)

    张海泉; 张彦华; 赵海燕

    2004-01-01

    Non-Fourier heat conduction induced by ultrafast heating of metals with a high-energy density beam was analyzed. The non-Fourier effects during high heat flux heating were illustrated by comparing the transient temperature response to different heat flux and material relaxation times. Based on the hyperbolic heat conduction equation for the non-Fourier heat conduction law, the equation was solved using a hybrid method combining an analytical solution and numerical inversion of the Laplace transforms for a semi-infinite body with the heat flux boundary. Analysis of the temperature response and distribution led to a criterion for the applicability of the non-Fourier heat conduction law. The results show that at a relatively large heat flux, such as greater than 108 W/cm2, the heat-affected zone in the metal material experiences a strong thermal shock as the non-Fourier effects cause a large step increase in the surface temperature. The results provide a method for analyzing transient heat conduction problems using a high-energy density beam, such as electron beam deep penetration welding.

  10. Beam collimator

    CERN Multimedia

    1977-01-01

    A four-block collimator installed on a control table for positioning the alignment reference marks. Designed for use with SPS secondary beams, the collimator operates under vacuum conditions. See Annual Report 1976 p. 121 and photo 7701014.

  11. Conceptual design for an electron-beam heated hypersonic wind tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Lipinski, R.J.; Kensek, R.P.

    1997-07-01

    There is a need for hypersonic wind-tunnel testing at about mach 10 and above using natural air and simulating temperatures and pressures which are prototypic of flight at 50 km altitude or below. With traditional wind-tunnel techniques, gas cooling during expansion results in exit temperatures which are too low. Miles, et al., have proposed overcoming this difficulty by heating the air with a laser beam as it expands in the wind-tunnel nozzle. This report discusses an alternative option of using a high-power electron beam to heat the air as it expands. In the e-beam heating concept, the electron beam is injected into the wind-tunnel nozzle near the exit and then is guided upstream toward the nozzle throat by a strong axial magnetic field. The beam deposits most of its power in the dense air near the throat where the expansion rate is greatest. A conceptual design is presented for a large-scale system which achieves Mach 14 for 0.1 seconds with an exit diameter of 2.8 meters. It requires 450 MW of electron beam power (5 MeV at 90 A). The guiding field is 500 G for most of the transport length and increases to 100 kG near the throat to converge the beam to a 1.0-cm diameter. The beam generator is a DC accelerator using a Marx bank (of capacitors) and a diode stack with a hot cathode. 14 refs. 38 figs., 9 tabs.

  12. Study of a Two-Pipe Chilled Beam System for both Cooling and Heating of Office Buildings

    DEFF Research Database (Denmark)

    Gordnorouzi, Rouzbeh; Hultmark, Göran; Afshari, Alireza;

    Active chilled beam systems are used to provide heating and cooling in order to achieve comfortable thermal indoor climate. For heating and cooling applications, an active chilled beam has two water circuits comprising four pipes that supply warm and cold water respectively to the beam coil...... according to the space demand. Lindab Comfort A/S has introduced an active chilled beam system which has just one water circuit (two pipes) that is used for both heating and cooling. The concept is based on high temperature cooling and low temperature heating. In this study the energy saving potential...

  13. Propagation of a laser beam in a time-varying waveguide. [plasma heating for controlled fusion

    Science.gov (United States)

    Chapman, J. M.; Kevorkian, J.

    1978-01-01

    The propagation of an axisymmetric laser beam in a plasma column having a radially parabolic electron density distribution is reported. For the case of an axially uniform waveguide it is found that the basic characteristics of alternating focusing and defocusing beams are maintained. However, the intensity distribution is changed at the foci and outer-beam regions. The features of paraxial beam propagation are discussed with reference to axially varying waveguides. Laser plasma coupling is considered noting the case where laser heating produces a density distribution radially parabolic near the axis and the energy absorbed over the focal length of the plasma is small. It is found that: (1) beam-propagation stability is governed by the relative magnitude of the density fluctuations existing in the axial variation of the waveguides due to laser heating, and (2) for beam propagation in a time-varying waveguide, the global instability of the propagation is a function of the initial fluctuation growth rate as compared to the initial time rate of change in the radial curvature of the waveguide.

  14. Reversible Electron Beam Heating for Suppression of Microbunching Instabilities at Free-Electron Lasers

    International Nuclear Information System (INIS)

    The presence of microbunching instabilities due to the compression of high-brightness electron beams at existing and future x-ray free-electron lasers (FELs) results in restrictions on the attainable lasing performance and renders beam imaging with optical transition radiation impossible. The instability can be suppressed by introducing additional energy spread, i.e., heating the electron beam, as demonstrated by the successful operation of the laser heater system at the Linac Coherent Light Source. The increased energy spread is typically tolerable for self-amplified spontaneous emission FELs but limits the effectiveness of advanced FEL schemes such as seeding. In this paper, we present a reversible electron beam heating system based on two transverse deflecting radio-frequency structures (TDSs) upstream and downstream of a magnetic bunch compressor chicane. The additional energy spread is introduced in the first TDS, which suppresses the microbunching instability, and then is eliminated in the second TDS. We show the feasibility of the microbunching gain suppression based on calculations and simulations including the effects of coherent synchrotron radiation. Acceptable electron beam and radio-frequency jitter are identified, and inherent options for diagnostics and on-line monitoring of the electron beam's longitudinal phase space are discussed.

  15. Reversible Electron Beam Heating for Suppression of Microbunching Instabilities at Free-Electron Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, Christopher; /DESY; Huang, Zhirong; Xiang, Dao; /SLAC

    2012-05-30

    The presence of microbunching instabilities due to the compression of high-brightness electron beams at existing and future x-ray free-electron lasers (FELs) results in restrictions on the attainable lasing performance and renders beam imaging with optical transition radiation impossible. The instability can be suppressed by introducing additional energy spread, i.e., heating the electron beam, as demonstrated by the successful operation of the laser heater system at the Linac Coherent Light Source. The increased energy spread is typically tolerable for self-amplified spontaneous emission FELs but limits the effectiveness of advanced FEL schemes such as seeding. In this paper, we present a reversible electron beam heating system based on two transverse deflecting radio-frequency structures (TDSs) upstream and downstream of a magnetic bunch compressor chicane. The additional energy spread is introduced in the first TDS, which suppresses the microbunching instability, and then is eliminated in the second TDS. We show the feasibility of the microbunching gain suppression based on calculations and simulations including the effects of coherent synchrotron radiation. Acceptable electron beam and radio-frequency jitter are identified, and inherent options for diagnostics and on-line monitoring of the electron beam's longitudinal phase space are discussed.

  16. Efficient Heating of Thin Cylindrical Targets by Broad Electromagnetic Beams II

    OpenAIRE

    Akhmeteli, Andrey

    2006-01-01

    In Part I (physics/0405091), it was shown that it is possible to achieve efficient heating of cylindrical targets by electromagnetic beams with transverse dimensions that are several orders of magnitude greater than those of the cylinder. Part II contains derivation of the detailed conditions of efficient heating in the longitudinal geometry and establishes a broader domain of parameters providing efficient heating in the transverse geometry. One possible implementation using currently availa...

  17. Long term creep tests on timber beams in heated and non-heated environments

    Energy Technology Data Exchange (ETDEWEB)

    Gowda, S.; Kortesmaa, M.; Ranta-Maunus, A. [VTT Building Technology, Espoo (Finland). Building Materials and Products

    1996-12-31

    The aim of this research investigation was to study the long term effect of creep on different wood materials under natural environmental conditions. The tests were initiated in the summer of 1992 and the results collected until the end of 1995 are reported here. The experiments on sawn timber of pine and spruce, glulam, Kerto-LVL and I-profile with hard board web structural size members were carried out in a sheltered environment, where the changes in moisture and temperature of the surrounding followed the natural climatic conditions of Southern Finland. In addition, separate tests on eight glulam beams were carried out in a heated room environment. The experiments were carried out at low load levels (2-7 MPa). The surface of few groups of specimens were treated with alkyd and emulsion paint, some were creosoted and salt impregnated, while few samples had no treatment. The creep test data of all specimens were analysed systematically to obtain creep curves. The data showed significant variation in creep among wood materials with different treatments. Creep of glulam was same in heated and non-heated environment. (orig.) (3 refs.)

  18. Beam induced heat loads on the beam-screens of the twin-bore magnets in the IRs of the HL-LHC

    CERN Document Server

    Iadarola, Giovanni; Rumolo, Giovanni

    2016-01-01

    The expected heat load induced on the beam screens has been evaluated for all the twin-bore magnets in the Insertion Regions (IRs) of the HL-LHC. The contribution from the impedance of the beam screen has been evaluated taking into account the presence of a longitudinal weld in the beam screen and the impact of the temperature and of the magnetic field on the resistivity of the surface. The contribution coming from electron cloud effects has been evaluated for different values of the Secondary Electron Yield of the surface based PyECLOUD build-up simulations.

  19. Laser Beam Focus Analyser

    DEFF Research Database (Denmark)

    Nielsen, Peter Carøe; Hansen, Hans Nørgaard; Olsen, Flemming Ove;

    2007-01-01

    The quantitative and qualitative description of laser beam characteristics is important for process implementation and optimisation. In particular, a need for quantitative characterisation of beam diameter was identified when using fibre lasers for micro manufacturing. Here the beam diameter limits...... the obtainable features in direct laser machining as well as heat affected zones in welding processes. This paper describes the development of a measuring unit capable of analysing beam shape and diameter of lasers to be used in manufacturing processes. The analyser is based on the principle of a rotating...... mechanical wire being swept through the laser beam at varying Z-heights. The reflected signal is analysed and the resulting beam profile determined. The development comprised the design of a flexible fixture capable of providing both rotation and Z-axis movement, control software including data capture...

  20. Neutral beam heating and current drive system and its role in ITER-FEAT operation scenarios

    International Nuclear Information System (INIS)

    The NB H and CD system, providing 33 MW in deuterium beams at 1 MeV from two injectors, in addition to 40 MW RF power, contributes to heating a plasma to sub-ignition through the L-H mode transition followed by finite-Q driven-burn (Q≥10), and achievement of a hybrid operation with an extended-duration (∼1000 s) or steady-state operation with Q≤5. To achieve such operations, the NB provides non-inductive current drive by injecting the beams tangentially into the plasma with the capability of on- and off-axis current drive. The present engineering design is under the constraints of the beam envelope, vacuum confinement, neutron shielding, tolerances, and clearances required with the toroidal field coils. The on- and off-axis current drive is to be achieved by tilting the beam axis vertically. Each beam axis of the NB injectors can be tilted independently, providing flexibility in the control of heating and the driven current profile. (author)

  1. Characterization of 1 MW, 40 keV, 1 s neutral beam for plasma heating

    International Nuclear Information System (INIS)

    Neutral beam with geometrical focusing for plasma heating in moderate-size plasma devices has been developed in Budker Institute of Nuclear Physics, Novosibirsk. When operated with hydrogen, the neutral beam power is 1 MW, pulse duration is 1 s, beam energy is 40 keV, and angular divergence is 1.2 deg. Initial ion beam is extracted and accelerated by triode multiapertures ion-optical system. To produce 1 MW neutral beam, about 40 A proton current is extracted with nominal current density of 320 mA/cm2. Ion-optical system has 200 mm diameter grids with 44% transparency. The grids have inertia cooling and heat is removed between the pulses by water flowing in channels placed on periphery of the grids. A plasma emitter for ion extraction is produced by rf-plasma box. Ion species mix of rf plasma source amounts to 70%, 20%, and 10% of H+, H2+, and H3+ ions, respectively, by current. Heavy impurities contribute less than 0.3%.

  2. Plasma heating in a long solenoid by a laser or a relativistic electron beam

    International Nuclear Information System (INIS)

    Advances in the technology of a large energy laser and/or relativistic electron beam (REB) generator have made it possible to seriously consider a long solenoid reactor concept. This concept has been reviewed. The physical problems in the plasma heating of the long solenoid by a laser or a REB are studied

  3. Conjugate Heat Transfer and Thermal Mechanical Analysis for Liquid Metal Targets for High Power Electron Beams.

    Energy Technology Data Exchange (ETDEWEB)

    Olivas, Eric Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-02-26

    A conjugate heat transfer and thermal structural analysis was completed, with the objective of determining the following: Lead bismuth eutectic (LBE) peak temperature, free convective velocity patterns in the LBE, peak beam window temperature, and thermal stress/deformation in the window.

  4. Metastable states' population of uranium atoms produced by electron-beam heating

    Energy Technology Data Exchange (ETDEWEB)

    Ohba, Hironori; Shibata, Takemasa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nishimura, Akihiko; Ogura, Koichi [Japan Atomic Energy Research Inst., Kansai Research Establishment, Advanced Photon Research Center, Kyoto (Japan)

    2000-08-01

    The metastable states' population densities of uranium atoms produced by electron-beam heating were measured by the laser induced fluorescence method. The atomic excitation temperature derived from the metastable state distribution was lower than the evaporation surface temperature. With increasing deposition rate, the atomic excitation temperature decreased to about 2000 K. (author)

  5. In Situ Tuning of Focused-Ion-Beam Defined Nanomechanical Resonators Using Joule Heating

    DEFF Research Database (Denmark)

    Homann, Lasse Vinther; Booth, Tim; Lei, Anders;

    2011-01-01

    min per device. Afterwards, the dynamic and structural properties of a double-clamped beam were measured after subsequent Joule heating events in order to ascertain the dependence of the internal structure on the Q-factor and resonant frequency of the device. It was observed that a change from...

  6. Radiation losses in PLT during neutral beam and ICRF heating experiments

    International Nuclear Information System (INIS)

    Radiation and charge exchange losses in the PLT tokamak are compared for discharges with ohmic heating only (OH), and with additional heating by neutral beams (NB) or RF in the ion cyclotron frequency range (ICRF). Spectroscopic, bolometric and soft x-ray diagnostics were used. The effects of discharge cleaning, vacuum wall gettering, and rate of gas inlet on radiation losses from OH plasmas and the correlation between radiation from plasma core and edge temperatures are discussed

  7. Heat transfer phenomena in gas protected particle beam fusion reactor cavities

    International Nuclear Information System (INIS)

    The behavior of the fireball produced in particle beam fusion reactor cavities as the cavity gas near the target absorbs the X-rays and ionic debris emanating from the microexplosion is examined. Thermal response of the first wall to the radiative heat flux from the gas is examined parametrically. Criteria for the suitability of different cavity fill gases based on their ability to protect the first wall from excessive surface heating and ablation are discussed. 9 refs

  8. Electron-beam heat treatment of thin band of low-carbon steel

    International Nuclear Information System (INIS)

    Using the methods of raster electron microscopy, X-ray structural and chemical analysis and also X-ray microanalysis, the change was studied in the mechanical properies of a band made of low-carbon steel 08 kp that takes place after electron-beam heat treatment. It has been shown that the above change is due to a specific character of the α reversible γ phase transition. After electron-beam treatment under optimum conditions, the properties of the band made of steel 08 kp and 0.15 mm thick (plasticity, ultimate strength, etc.) are similar to those obtained using the conventional procedures (annealing and skin pass rolling)

  9. Implementation of a quasi-realtime display of DIII-D neutral beam heating waveforms

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, J.C.

    1993-10-01

    The DIII-D neutral beam system employs eight 80 keV ion sources mounted on four beamlines to provide plasma heating to the DIII-D tokamak. The neutral beam system is capable of injecting over 20 MW of deuterium power with flexibility in terms of timing and modulation of the individual neutral beams. To maintain DIII-D`s efficient tokamak shot cycle and make informed control decisions, it is important to be able to determine which beams fired, and exactly when, by the time the tokamak shot is over. Previously this information was available in centralized form only after a several minute wait. A cost-effective alternative to the traditional eight-channel storage oscilloscope has been implemented using off the shelf PC hardware and software. The system provides a real time display of injected neutral beam accelerator voltages and tokamak plasma current, as well an a summation waveform indicative of the total injected power as a function of time. The hardware consists of a Macintosh Centris 650 PC with a Motorola 68040 microprocessor. Data acquisition is accomplished using a National Instrument`s 16-channel analog to digital conversion board for the Macintosh. The color displays and functionality were developed using National Instruments` LabView environment. Because the price of PCs has been decreasing rapidly and their capabilities increasing, this system is far less expensive than an eight-channel storage oscilloscope. As a flexible combination of PC and software, the system also provides much more capability than a dedicated oscilloscope, acting as the neutral beam coordinator`s logbook, recording comments and availability statistics. Data such as shot number and neutral beam parameters are obtained over the local network from other computers and added to the display. Waveforms are easily archived to disk for future recall. Details of the implementation will be discussed along with samples of the displays and a description of the system`s function and capabilities.

  10. Development of a high-heat-flux target for multimegawatt, multisecond neutral beams at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Combs, S.K.; Milora, S.L.; Bush, C.E.; Foster, C.A.; Haselton, H.H.; Hayes, P.H.; Menon, M.M.; Moeller, J.A.; Sluss, F.; Tsai, C.C.

    1984-01-01

    A high-heat-flux target has been developed for intercepting multimegawatt, multisecond neutral beam power at the Oak Ridge National Laboratory (ORNL). Water-cooled copper swirl tubes are used for the heat transfer medium; these tubes exhibit an enhancement in burnout heat flux over conventional axial-flow tubes. The target consists of 126 swirl tubes (each 0.95 cm in outside diameter with 0.16-cm-thick walls and approx. =1 m long) arranged in a V-shape. Two arrays of parallel tubes inclined at an angle ..cap alpha.. to the beam axis form the V-shape, and this geometry reduces the surface heat flux by a factor of 1/sin ..cap alpha.. (for the present design, ..cap alpha.. =13/sup 0/ and 21/sup 0/). In tests with the ORNL long-pulse ion source (13- by 43-cm grid), the target has handled up to 3-MW, 30-s beam pulses with no deleterious effects. The peak power density was estimated at approx. =15 kW/cm/sup 2/ normal to the beam axis (5.4 kW/cm/sup 2/ maximum on tube surfaces). The water flow rate through the target was 41.6 L/s (660 gpm) or 0.33 L/s (5.2 gpm) per tube (axial flow velocity = 11.6 m/s). The corresponding pressure drop across the target was 1.14 MPa (165 psi) with an inlet pressure of 1.45 MPa (210 psia). Data are also presented from backup experiments in which individual tubes were heated by a small ion source (10-cm-diam grid) to characterize tube performance. These results suggest that the target should handle peak power densities in the range 25 to 30 kW/cm/sup 2/ normal to the beam axis (approx. =10 kW/cm/sup 2/ maximum on tube surfaces) with the present flow parameters. This translates to beam power levels of 5 to 6 MW for equivalent beam optics.

  11. Innovative two-pipe active chilled beam system for simultaneous heating and cooling of office buildings

    DEFF Research Database (Denmark)

    Maccarini, Alessandro; Afshari, Alireza; Bergsøe, Niels Christian;

    2014-01-01

    energy between zones with one hydronic circuit, operating with a water temperature between 20°C and 23°C. To calculate the energy performance of the system, simulation-based research was developed. The two-pipe system was modelled by using EnergyPlus, a whole building energy simulation program. Hourly......The aim of this paper was to investigate the energy savings potential of an innovative two-pipe system in an active chilled beam application for heating and cooling of office buildings. The characteristic of the system is its ability to provide simultaneous heating and cooling by transferring...... heating, cooling and ventilation loads were calculated by the program and an annual energy consumption evaluation of the system was made. Simulation results showed that the innovative two-pipe active chilled beam system used approximately 5% less energy than a conventional four-pipe system....

  12. External Beam Therapy (EBT)

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z External Beam Therapy (EBT) External beam therapy (EBT) is a ... follow-up should I expect? What is external beam therapy and how is it used? External beam ...

  13. Optimal design of a beam stop for Indus-2 using finite element heat transfer studies

    Indian Academy of Sciences (India)

    A K Sinha; K J S Sawhney; R V Nandedkar

    2001-12-01

    This paper describes the design of an in-vacuum, water-cooled beam stop (X-ray shutter) for the materials science (X-ray diffraction) beamline proposed to be built on the wavelength shifter in the Indus-2 (2.5 GeV) synchrotron radiation source. The radiation source impinges ∼ 1 kW power on the beam stop and the heat transfer capabilities of the beam stop have been evaluated. Temperature distribution in the beam stop has been obtained under various cooling conditions using the finite element analysis calculations with ANSYS software. Design parameters of the beam stop have been optimised. It is also shown that radiation cooling alone is not sufficient for taking away the heat load. Water-cooling of the beam stop is essential.

  14. Research on modeling of heat source for electron beam welding fusion-solidification zone

    Institute of Scientific and Technical Information of China (English)

    Wang Yajun; Fu Pengfei; Guan Yongjun; Lu Zhijun; Wei Yintao

    2013-01-01

    In this paper,the common heat source model of point and linear heat source in the numerical simulation of electron beam welding (EBW) were summarized and introduced.The combined point-linear heat source model was brought forward and to simulate the welding temperature fields of EBW and predicting the weld shape.The model parameters were put forward and regulated in the combined model,which included the ratio of point heat source to linear heat source Qpr and the distribution of linear heat source Lr.Based on the combined model,the welding temperature fields of EBW were investigated.The results show that the predicted weld shapes are conformable to those of the actual,the temperature fields are reasonable and correct by simulating with combined point-linear heat source model and the typical weld shapes are gained.

  15. Non-invasive measurement of X-ray beam heating on a surrogate crystal sample.

    Science.gov (United States)

    Snell, Edward H; Bellamy, Henry D; Rosenbaum, Gerd; van der Woerd, Mark J

    2007-01-01

    Cryocooling is a technique routinely used to mitigate the effects of secondary radiation damage on macromolecules during X-ray data collection. Energy from the X-ray beam absorbed by the sample raises the temperature of the sample. How large is the temperature increase and does this reduce the effectiveness of cryocooling? Sample heating by the X-ray beam has been measured non-invasively for the first time by means of thermal imaging. Specifically, the temperature rise of 1 mm and 2 mm glass spheres (sample surrogates) exposed to an intense synchrotron X-ray beam and cooled in a laminar flow of nitrogen gas is experimentally measured. For the typical sample sizes, photon energies, fluxes, flux densities and exposure times used for macromolecular crystallographic data collection at third-generation synchrotron radiation sources and with the sample accurately centered in the cryostream, the heating by the X-ray beam is only a few degrees. This is not sufficient to raise the sample above the amorphous-ice/crystalline-ice transition temperature and, if the cryostream cools the sample to 100 K, not even enough to significantly enhance radiation damage from secondary effects.

  16. Ultrasonic testing of the depth of penetration of electron beam welds on heat exchanger tubes to tube plate assemblies

    International Nuclear Information System (INIS)

    A focused beam ultrasonic testing method is described, which controls weld penetration and more precisely welded zone depth. This technique has been applied to the control of electron beam welds of tube to plate assemblies on heat exchangers; electron beam welding, interesting from economical and technical points of view, induces irregularities in weld penetration. Used as a quality control method, it allows to precisely record some welding parameters (penetration depth, compactness defects, root shape...)

  17. A spectroscopic study of impurity behavior in neutral-beam and ohmically heated TFTR discharges

    International Nuclear Information System (INIS)

    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

  18. The application of arbitrary incidence laser beams heat treatment temperature field calculation formulas

    Institute of Scientific and Technical Information of China (English)

    Kun Ma; Junchang Li; Zebin Fan; Jinbin Gui; Yingxiong Qin; Qiguang Zheng

    2005-01-01

    @@ Based on the calculation formulas of heat treatment temperature field for an arbitrary incident laser intensity distribution, the transformation intensity distribution of CO2 laser beam passing an integrating mirror is studied theoretically and experimentally. The derived formulas are applied in laser heat treatment research which is transformed by optical system, and the theoretical calculation results are compared with experimental results. It is shown that the formulas can be used to calculate the laser heat treatment temperature field accurately, and the calculation speed is obviously faster than the numerical calculation methods with the same precision. The calculation software can be used to select proper experiment parameters.

  19. Electron beam heating effects during environmental scanning electron microscopy imaging of water condensation on superhydrophobic surfaces

    Science.gov (United States)

    Rykaczewski, K.; Scott, J. H. J.; Fedorov, A. G.

    2011-02-01

    Superhydrophobic surfaces (SHSs) show promise as promoters of dropwise condensation. Droplets with diameters below ˜10 μm account for the majority of the heat transferred during dropwise condensation but their growth dynamics on SHS have not been systematically studied. Due to the complex topography of the surface environmental scanning electron microscopy is the preferred method for observing the growth dynamics of droplets in this size regime. By studying electron beam heating effects on condensed water droplets we establish a magnification limit below which the heating effects are negligible and use this insight to study the mechanism of individual drop growth.

  20. Confinement scaling studies of radiofrequency and neutral beam heated currentless heliotron E plasmas

    International Nuclear Information System (INIS)

    Parametric scaling studies of radiofrequency and neutral beam heated currentless Heliotron E plasmas have been performed. The parametric local electron transport analyses show that the electron energy transport in electron cyclotron heating (ECH) plasmas is nearly of the same magnitude as the neoclassically predicted transport inside the 2/3 radius, while neutral beam injection (NBI) plasmas and plasmas in the ion cyclotron range of frequencies (ICRF) are dominated by anomalous electron transport in the entire region. Scaling studies on the global energy confinement time reveal that ECH, NBI and ICRF plasmas obey approximately identical scalings that are characterized by continuous power degradation and favourable positive density dependence. The global energy confinement time is thought to be affected by the anomalous transport in the peripheral plasma regions in the same way for ECH, NBI and ICRF plasmas although the core plasma properties - such as local electron transport - seem to be different for the individual plasmas. (author). 39 refs, 11 figs

  1. Beam quality measure for vector beams.

    Science.gov (United States)

    Ndagano, Bienvenu; Sroor, Hend; McLaren, Melanie; Rosales-Guzmán, Carmelo; Forbes, Andrew

    2016-08-01

    Vector beams have found a myriad of applications, from laser materials processing to microscopy, and are now easily produced in the laboratory. They are usually differentiated from scalar beams by qualitative measures, for example, visual inspection of beam profiles after a rotating polarizer. Here we introduce a quantitative beam quality measure for vector beams and demonstrate it on cylindrical vector vortex beams. We show how a single measure can be defined for the vector quality, from 0 (purely scalar) to 1 (purely vector). Our measure is derived from a quantum toolkit, which we show applies to classical vector beams. PMID:27472580

  2. Effect of two steel plate's interface on heat transfer under laser beam irradiation

    CERN Document Server

    Zhao Jian Heng; Zhang Shi Wen; Gui Yuan Zhen; Wang Chun Yan; Tang Xiao Song; Zhang Da Yong

    2002-01-01

    It is supposed that there is a gap in the interface of two contacting steel plates due to thermal deformation under laser beam irradiation, and this gap will affect heat transfer in this interface obviously. This supposition is testified by experiments and simulation. This work is helpful to the study of the destruction mechanism under high power laser loading, and provides an effective way for anti-laser research

  3. Transport modeling of ECH and neutral-beam-heated plasmas in the advanced toroidal facility

    Energy Technology Data Exchange (ETDEWEB)

    Howe, H.C.; Horton, L.D.; Crume, E.C.; Harris, J.H.; Isler, R.C.; Wilgen, J.B.; Wing, W.R.

    1989-01-01

    Results of time-dependent transport modeling of the ATF plasmas are compared with a typical ungettered, neutral-beam-heated discharge. A summary of ATF machine parameters is given by Murakami. The model is adjusted to give agreement between measured diagnostics signals and the corresponding values inferred from the model plasma. With this agreement, the main features of the discharge are reproduced including the radiation-induced temperature collapse. 7 refs., 6 figs.

  4. Stable beams

    CERN Multimedia

    2015-01-01

    Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure.   I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...

  5. Beam propagation

    International Nuclear Information System (INIS)

    The main part of this thesis consists of 15 published papers, in which the numerical Beam Propagating Method (BPM) is investigated, verified and used in a number of applications. In the introduction a derivation of the nonlinear Schroedinger equation is presented to connect the beginning of the soliton papers with Maxwell's equations including a nonlinear polarization. This thesis focuses on the wide use of the BPM for numerical simulations of propagating light and particle beams through different types of structures such as waveguides, fibers, tapers, Y-junctions, laser arrays and crystalline solids. We verify the BPM in the above listed problems against other numerical methods for example the Finite-element Method, perturbation methods and Runge-Kutta integration. Further, the BPM is shown to be a simple and effective way to numerically set up the Green's function in matrix form for periodic structures. The Green's function matrix can then be diagonalized with matrix methods yielding the eigensolutions of the structure. The BPM inherent transverse periodicity can be untied, if desired, by for example including an absorptive refractive index at the computational window edges. The interaction of two first-order soliton pulses is strongly dependent on the phase relationship between the individual solitons. When optical phase shift keying is used in coherent one-carrier wavelength communication, the fiber attenuation will suppress or delay the nonlinear instability. (orig.)

  6. Relativistic Pair Beams from TeV Blazars: A Source of Reprocessed GeV Emission rather than Intergalactic Heating

    Science.gov (United States)

    Sironi, Lorenzo; Giannios, Dimitrios

    2014-05-01

    The interaction of TeV photons from blazars with the extragalactic background light produces a relativistic beam of electron-positron pairs streaming through the intergalactic medium (IGM). The fate of the beam energy is uncertain. By means of two- and three-dimensional particle-in-cell simulations, we study the nonlinear evolution of dilute ultra-relativistic pair beams propagating through the IGM. We explore a wide range of beam Lorentz factors γ b Gt 1 and beam-to-plasma density ratios α Lt 1, so that our results can be extrapolated to the extreme parameters of blazar-induced beams (γ b ~ 106 and α ~ 10-15, for powerful blazars). For cold beams, we show that the oblique instability governs the early stages of evolution, but its exponential growth terminates—due to self-heating of the beam in the transverse direction—when only a negligible fraction ~(α/γ b )1/3 ~ 10-7 of the beam energy has been transferred to the IGM plasma. Further relaxation of the beam proceeds through quasi-longitudinal modes, until the momentum dispersion in the direction of propagation saturates at Δp b, ∥/γ b mec ~ 0.2. This corresponds to a fraction ~10% of the beam energy—irrespective of γ b or α—being ultimately transferred to the IGM plasma (as compared to the heating efficiency of ~50% predicted by one-dimensional models, which cannot properly account for the transverse broadening of the beam). For the warm beams generated by TeV blazars, the development of the longitudinal relaxation is suppressed, since the initial dispersion in beam momentum is already Δp b0, ∥/γ b mec >~ 1. Here, the fraction of beam energy ultimately deposited into the IGM is only ~α γ b ~ 10-9. It follows that most of the beam energy is still available to power the GeV emission produced by inverse Compton up-scattering of the cosmic microwave background by the beam pairs.

  7. Visualizing expanding warm dense matter heated by laser-generated ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Woosuk [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-24

    This PowerPoint presentation concluded with the following. We calculated the expected heating per atom and temperatures of various target materials using a Monte Carlo simulation code and SESAME EOS tables. We used aluminum ion beams to heat gold and diamond uniformly and isochorically. A streak camera imaged the expansion of warm dense gold (5.5 eV) and diamond (1.7 eV). GXI-X recorded all 16 x-ray images of the unheated gold bar targets proving that it could image the motion of the gold/diamond interface of the proposed target.

  8. Sensitivity of Displaced-Beam Scintillometer Measurements of Area-Average Heat Fluxes to Uncertainties in Topographic Heights

    CERN Document Server

    Gruber, Matthew; Hartogensis, Oscar

    2014-01-01

    Displaced-beam scintillometer measurements of the turbulence inner-scale length $l_o$ and refractive index structure function $C_n^2$ resolve area-average turbulent fluxes of heat and momentum through the Monin-Obukhov similarity equations. Sensitivity studies have been produced for the use of displaced-beam scintillometers over flat terrain. Many real field sites feature variable topography. We develop here an analysis of the sensitivity of displaced-beam scintillometer derived sensible heat fluxes to uncertainties in spacially distributed topographic measurements. Sensitivity is shown to be concentrated in areas near the center of the beam and where the underlying topography is closest to the beam height. Uncertainty may be decreased by taking precise topographic measurements in these areas.

  9. Uniform heating of materials into the warm dense matter regime with laser-driven quasi-monoenergetic ion beams

    CERN Document Server

    Bang, W; Bradley, P A; Vold, E L; Boettger, J C; Fernández, J C

    2015-01-01

    In a recent experiment on the Trident laser facility, a laser-driven beam of quasi-monoenergetic aluminum ions was used to heat solid gold and diamond foils isochorically to 5.5 eV and 1.7 eV, respectively. Here theoretical calculations are presented that suggest the gold and diamond were heated uniformly by these laser-driven ion beams. According to calculations and SESAME equation-of-state tables, laser-driven aluminum ion beams achievable on Trident, with a finite energy spread of (delta E)/E ~ 20%, are expected to heat the targets more uniformly than a beam of 140 MeV aluminum ions with zero energy spread. The robustness of the expected heating uniformity relative to the changes in the incident ion energy spectra is evaluated, and expected plasma temperatures of various target materials achievable with the current experimental platform are presented.

  10. STRUCTURE AND CHARACTERISTICS OF TI-AL-NI SYSTEM COVERING, APPLIED ON THE STEEL GROUND USING ELECTRON-BEAM HEATING

    Directory of Open Access Journals (Sweden)

    I. V. Murashova

    2011-01-01

    Full Text Available The morphology of the system Ti-Al-Ni covering, received by means of self-distributing high-temperature synthesis, initiated by electron-beam heating, on the basis of steel St3 is investigated.

  11. Beam-beam effects in the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, V.; Alexahin, Y.; Lebedev, V.; Lebrun, P.; Moore, R.S.; Sen, T.; Tollestrup, A.; Valishev, A.; Zhang, X.L.; /Fermilab

    2005-01-01

    The Tevatron in Collider Run II (2001-present) is operating with 6 times more bunches, many times higher beam intensities and luminosities than in Run I (1992-1995). Electromagnetic long-range and head-on interactions of high intensity proton and antiproton beams have been significant sources of beam loss and lifetime limitations. We present observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies. We analyze the data and various methods employed in operations, predict the performance for planned luminosity upgrades, and discuss ways to improve it.

  12. Beam halo in high-intensity beams

    International Nuclear Information System (INIS)

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. The author describes what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. Initial results are presented from a study of beam entropy for an intense space-charge dominated beam

  13. Beam imaging sensor

    Energy Technology Data Exchange (ETDEWEB)

    McAninch, Michael D.; Root, Jeffrey J.

    2016-07-05

    The present invention relates generally to the field of sensors for beam imaging and, in particular, to a new and useful beam imaging sensor for use in determining, for example, the power density distribution of a beam including, but not limited to, an electron beam or an ion beam. In one embodiment, the beam imaging sensor of the present invention comprises, among other items, a circumferential slit that is either circular, elliptical or polygonal in nature.

  14. Opal neutron beams shutters

    International Nuclear Information System (INIS)

    Full text: The Opal Reactor has five beam tubes for neutron beams. Of these 5 tubes, two come from a cold neutron source, another two from thermal sources, and a fifth is ready for a future hot neutron source. Neutron guides come from the cold and thermal beam tubes. Neutron beams are enabled/disabled through shutters located inside the reactor pool's radial shield. These shutters were specially designed by INVAP for the OPAL reactor. They comprise fixed and movable shields. The movable part allows neutron beam enabling or disabling. The design of these shutters demanded the construction of prototypes that were further submitted to comprehensive tests to be qualified in light of the strict movement precision and high reliability requirements involved. The shielding material - a plastic and steel mix - was also specifically designed for this facility. The design required great efforts as to shield calculation and energy deposition. A heat removal system was designed to dissipate the energy absorbed by the shields. The cold and thermal beam shutters are built following a single vertical axis design. The hot shutter, due to different requirements, was designed with a horizontal axis

  15. High power beam analysis

    Science.gov (United States)

    Aharon, Oren

    2014-02-01

    In various modern scientific and industrial laser applications, beam-shaping optics manipulates the laser spot size and its intensity distribution. However the designed laser spot frequently deviates from the design goal due to real life imperfections and effects, such as: input laser distortions, optical distortion, heating, overall instabilities, and non-linear effects. Lasers provide the ability to accurately deliver large amounts of energy to a target area with very high accuracy. Thus monitoring beam size power and beam location is of high importance for high quality results and repeatability. Depending on the combination of wavelength, beam size and pulse duration , laser energy is absorbed by the material surface, yielding into processes such as cutting, welding, surface treatment, brazing and many other applications. This article will cover the aspect of laser beam measurements, especially at the focal point where it matters the most. A brief introduction to the material processing interactions will be covered, followed by fundamentals of laser beam propagation, novel measurement techniques, actual measurement and brief conclusions.

  16. An electron-beam-heating model for the Gamble II rod pinch

    International Nuclear Information System (INIS)

    The rod-pinch diode concentrates electron deposition onto the tip of a high-atomic-number, mm-dia. anode rod to create an ultra-bright x-ray source for multi-MV radiography. Here, a technique is presented whereby line-spread functions acquired on-axis and at 90 deg. to the rod are used to determine the electron-deposition distribution. Results show that the smaller measured on-axis spot size for heated rods on Gamble II is due to pinching closer to the tapered tip. For a diode power of 6x1010 W, peak electron heating of 1x1014 W/cm3 is calculated. MHD calculations of the e-beam-heated rod response agree with Schlieren measurements of plasma expansion

  17. Correction of resist heating effect on variable shaped beam mask writer

    Science.gov (United States)

    Nakayamada, Noriaki; Suganuma, Mizuna; Nomura, Haruyuki; Kato, Yasuo; Kamikubo, Takashi; Ogasawara, Munehiro; Zable, Harold; Masuda, Yukihiro; Fujimura, Aki

    2016-04-01

    The specifications for critical dimension (CD) accuracy and line edge roughness are getting tighter to promote every photomask manufacturer to choose electron beam resists of lower sensitivity. When the resist is exposed by too many electrons, it is excessively heated up to have higher sensitivity at a higher temperature, which results in degraded CD uniformity. This effect is called "resist heating effect" and is now the most critical error source in CD control on a variable shaped beam (VSB) mask writer. We have developed an on-tool, real-time correction system for the resist heating effect. The system is composed of correction software based on a simple thermal diffusion model and computational hardware equipped with more than 100 graphical processing unit chips. We have demonstrated that the designed correction accuracy was obtained and the runtime of correction was sufficiently shorter than the writing time. The system is ready to be deployed for our VSB mask writers to retain the writing time as short as possible for lower sensitivity resists by removing the need for increased pass count.

  18. Study of the heating of tokamaks by high energy ion beams

    International Nuclear Information System (INIS)

    This research program has encompassed a number of design studies for a steady state (or long pulse) Auto-Resonant Accelerator (ARA) capable of producing intense beams of high energy (4-20 MEV) ions suitable for the heating of large tokamak devices. The different research topics addressed have ranged over a number of questions related to the design of the individual elements of the accelerator itself, along with studies of the injection and stripping of the accelerated ions in the tokamak and their subsequent energy deposition in the tokamak plasma

  19. HF beam parameters in ELF/VLF wave generation via modulated heating of the ionosphere

    OpenAIRE

    İnan, Umran Savaş; Cohen, M. B. ; Golkowski, M. ; Lehtinen, N. G. ; McCarrick, M. J.

    2012-01-01

    ELF/VLF (0.3–30 kHz) wave generation is achievable via modulated HF (3–30 MHz) heating of the lower ionosphere in the presence of natural currents such as the auroral electrojet. Using the 3.6 MW High Frequency Active Auroral Research Program (HAARP) facility near Gakona, AK, we investigate the effect of HF frequency and beam size on the generated ELF/VLF amplitudes, as a function of modulation frequency, and find that generation in the Earth-ionosphere waveguide generally decr...

  20. A symplectic coherent beam-beam model

    International Nuclear Information System (INIS)

    We consider a simple one-dimensional model to study the effects of the beam-beam force on the coherent dynamics of colliding beams. The key ingredient is a linearized beam-beam kick. We study only the quadrupole modes, with the dynamical variables being the 2nd-order moments of the canonical variables q, p. Our model is self-consistent in the sense that no higher order moments are generated by the linearized beam-beam kicks, and that the only source of violation of symplecticity is the radiation. We discuss the round beam case only, in which vertical and horizontal quantities are assumed to be equal (though they may be different in the two beams). Depending on the values of the tune and beam intensity, we observe steady states in which otherwise identical bunches have sizes that are equal, or unequal, or periodic, or behave chaotically from turn to turn. Possible implications of luminosity saturation with increasing beam intensity are discussed. Finally, we present some preliminary applications to an asymmetric collider. 8 refs., 8 figs

  1. Literature in Focus Beta Beams: Neutrino Beams

    CERN Multimedia

    2009-01-01

    By Mats Lindroos (CERN) and Mauro Mezzetto (INFN Padova, Italy) Imperial Press, 2009 The beta-beam concept for the generation of electron neutrino beams was first proposed by Piero Zucchelli in 2002. The idea created quite a stir, challenging the idea that intense neutrino beams only could be produced from the decay of pions or muons in classical neutrino beams facilities or in future neutrino factories. The concept initially struggled to make an impact but the hard work by many machine physicists, phenomenologists and theoreticians over the last five years has won the beta-beam a well-earned position as one of the frontrunners for a possible future world laboratory for high intensity neutrino oscillation physics. This is the first complete monograph on the beta-beam concept. The book describes both technical aspects and experimental aspects of the beta-beam, providing students and scientists with an insight into the possibilities o...

  2. Parametric scaling studies of the energy confinement time for neutral beam heated Heliotron E plasmas

    International Nuclear Information System (INIS)

    A kinetic analysis of the global energy confinement time for neutral beam heated Heliotron E plasmas has been performed with a 1-D, time independent transport analysis code, PROCTR-Mod. From a regression analysis of a representative sample selection of the presented data sets, the global energy confinement time, τEG(ms), is found to scale as τEG=13n-bareαPheatβBγ, where α=0.53±0.10, β=-0.71±0.09, and γ=0.35±0.14; the error bar indicates the 95% confidence region deduced from the limited data points; n-bare(1014cm-3) is the line average electron density; Pheat(MW) is the neutral beam heating power; and B(T) is the vacuum magnetic field at the magnetic axis. The data analysis shows that the favourable density dependence partially offsets the unfavourable power dependence and that anomalous electron transport loss becomes dominant in the overall energy balance as the beam power and the plasma density are increased. An alternative scaling law is also presented, which is to fit τEG(ms) by an 'offset linear' law, τEG=ζB2+ηe>/Pheat, where ζ=1.1±0.33 and η=15.0±1.9; e>(1014cm-3) is the volume average electron density. The latter scaling is found to provide a better fit to the presented data sets, in spite of its simple form. The parametric scaling of the local electron thermal diffusivity, χe, is also discussed on the basis of the kinetic analysis. (author). 40 refs, 21 figs, 2 tabs

  3. Explanation of Turbulent Suppression of Electron Heat Transfer in GOL-3 Facility at the Stage of Relativistic Electron Beam Injection

    International Nuclear Information System (INIS)

    The effect of the electron heat transfer suppression during the stage of relativistic electron beam injection into a plasma was discovered experimentally more than a decade ago. It is now widely adopted that the suppression is a side sequel of Langmuir turbulence excited by the beam, however neither quantitative theory nor even rough estimates of the phenomena were available so far. We argue that the coefficient of turbulent thermal conductivity can be evaluated from a robust judgement based on the energy balance consideration

  4. Visualization of expanding warm dense gold and diamond heated rapidly by laser-generated ion beams

    International Nuclear Information System (INIS)

    With the development of several novel heating sources, scientists can now heat a small sample isochorically above 10,000 K. Although matter at such an extreme state, known as warm dense matter, is commonly found in astrophysics (e.g., in planetary cores) as well as in high energy density physics experiments, its properties are not well understood and are difficult to predict theoretically. This is because the approximations made to describe condensed matter or high-temperature plasmas are invalid in this intermediate regime. A sufficiently large warm dense matter sample that is uniformly heated would be ideal for these studies, but has been unavailable to date. We have used a beam of quasi-monoenergetic aluminum ions to heat gold and diamond foils uniformly and isochorically. For the first time, we visualized directly the expanding warm dense gold and diamond with an optical streak camera. Furthermore, we present a new technique to determine the initial temperature of these heated samples from the measured expansion speeds of gold and diamond into vacuum. We anticipate the uniformly heated solid density target will allow for direct quantitative measurements of equation-of-state, conductivity, opacity, and stopping power of warm dense matter, benefiting plasma physics, astrophysics, and nuclear physics

  5. Telecommunication using muon beams

    Science.gov (United States)

    Arnold, Richard C.

    1976-01-01

    Telecommunication is effected by generating a beam of mu mesons or muons, varying a property of the beam at a modulating rate to generate a modulated beam of muons, and detecting the information in the modulated beam at a remote location.

  6. Electron-beam welding of the grill flanges of the FTU additional heating system

    International Nuclear Information System (INIS)

    The research and development program of the fusion sector of ENEA (Italian Agency for New Technologies, Energy and Environment) Frascati center is mainly based on experiments on the Frascati Tokamak Upgrade (FTU) machine. The FTU is a medium-high magnetic field (8 T) tokamak with a radio-frequency (RF) additional heating system (8 MW, 8 GHz) that can heat the plasma to temperatures of fusionistic interest. The RF power is coupled to the plasma by a coupling structure consisting of three grills, each formed of an array of waveguides welded at the terminal flanges by an electron-beam technique. This solution allows highly accurate dimensions and optimum clean-surface conditions of the welded copper joints

  7. Armor plate protection for the Doublet III vacuum vessel for neutral beam heating

    International Nuclear Information System (INIS)

    The design of vacuum vessel armor plate for neutral beam systems presents a number of challenges to the engineer. Heat fluxes of several hundred watts/cm2 must be handled on a routine basis during normal plasma operations, and a factor of ten increase in these fluxes can occur during plasma disruptions. At the present time, a graphite tile system appears to be the best candidate for such a situation. Heat fluxes in excess of 4 kW/cm2 can be routinely sustained and the material sputtered or evaporated from the surface has a low atomic number. The system proposed for Doublet III will provide valuable data for the designers of future fusion reactors and will also provide proof-of-principle demonstrations for such machines as TFTR and JET

  8. NUMERICAL ANALYSIS OF RESIDUAL STRESSES IN TITANIUM ALLOY DURING ELECTRON BEAM LOCAL POST-WELD HEAT TREATMENT

    Institute of Scientific and Technical Information of China (English)

    Chen Furong; Huo Lixing; Zhang Yufeng; Liu Fangjun; Chen Gang

    2005-01-01

    The distributions of temperature and residual stresses in thin plates of BT20 titanium alloy are numerically analyzed by three-dimensional finite element software during electron beam welding and electron beam local post-weld heat treatment (EBLPWHT). Combined with numerical calculating results, the effects of different EBLPWHT mode and parameters, including heat treating position,heating width and heating time, on the distribution of welding residual stresses are analyzed. The results show that, the residual tensile stresses in weld center can be largely decreased when the weld is heat treated at back preface of the plate. The numerical results also indicated that the magnitude of the residual longitudinal stresses of the weld and the zone vicinity of the weld is decreased, and the range of the residual longitudinal stresses is increased along with the increase of heating width and heating time.

  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. Parabolic scaling beams.

    Science.gov (United States)

    Gao, Nan; Xie, Changqing

    2014-06-15

    We generalize the concept of diffraction free beams to parabolic scaling beams (PSBs), whose normalized intensity scales parabolically during propagation. These beams are nondiffracting in the circular parabolic coordinate systems, and all the diffraction free beams of Durnin's type have counterparts as PSBs. Parabolic scaling Bessel beams with Gaussian apodization are investigated in detail, their nonparaxial extrapolations are derived, and experimental results agree well with theoretical predictions.

  11. Ion beam diagnosis

    International Nuclear Information System (INIS)

    This report is an introduction to ion beam diagnosis. After a short description of the most important ion beam parameters measurements of the beam current by means of Faraday cups, calorimetry, and beam current transformers and measurements of the beam profile by means of viewing screens, profile grids and scanning devices, and residual gas ionization monitors are described. Finally measurements in the transverse and longitudinal phase space are considered. (HSI)

  12. High-power ICRF and ICRF plus neutral-beam heating on PLT

    International Nuclear Information System (INIS)

    PLT ICRF experiments with RF powers up to approx.=3 MW have demonstrated efficient plasma heating in both the minority fundamental and the second harmonic ion-cyclotron regimes. In the minority 3He regime, ion temperatures of approx.=3 keV have been produced along with approx.=1 kW of D-3He fusion power and substantial electron heating. In the second harmonic H regime, an equivalent averaged ion energy of approx.=4 keV has been achieved. Combined ICRF plus neutral-beam heating experiments with auxiliary powers totalling up to 4.5 MW have provided insight into auxiliary heating performance at stored plasma energy levels up to approx.=100 kJ. Values of #betta#sub(phi) in the range of 1.5-2% have been attained for Bsub(phi) approx.=17 kG. Energetic discharges with n-barsub(e) up to approx.6x1013 cm-3 at Bsub(phi) approx.=28 kG have also been investigated. Preliminary confinement studies suggest that energetic ion losses may contribute to a direct loss of the input RF power in the H minority heating regime but are insignificant in the 3He minority case. The energy confinement time for the H minority regime is reduced somewhat from the Ohmic value. (author)

  13. Anomalous electron heating and energy balance in an ion beam generated plasma

    International Nuclear Information System (INIS)

    The plasma described in this report is generated by a 15 to 34 kV ion beam, consisting primarily of protons, passing through an H2 gas cell neutralizer. Plasma ions (or ion-electron pairs) are produced by electron capture from (or ionization of) gas molecules by beam ions and atoms. An explanation is provided for the observed anomalous behavior of the electron temperature (T/sub e/): a step-lite, nearly two-fold jump in T/sub e/ as the beam current approaches that which minimizes beam angular divergence; insensitivity of T/sub e/ to gas pressure; and the linear relation of T/sub e/ to beam energy

  14. Recent progress of high-power negative ion beam development for fusion plasma heating

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Kazuhiro; Akino, Noboru; Aoyagi, Tetsuo [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment] [and others

    1997-03-01

    A negative-ion-based neutral beam injector (N-NBI) has been constructed for JT-60U. The N-NBI is designed to inject 500 keV, 10 MW neutral beams using two ion sources, each producing a 500 keV, 22 A D{sup -} ion beam. Beam acceleration test started in July, 1995 using one ion source. In the preliminary experiment, D{sup -} ion beam of 13.5 A has been successfully accelerated with an energy of 400 keV (5.4 MW) for 0.12 s at an operating pressure of 0.22 Pa. This is the highest D{sup -} beam current and power in the world. Co-extracted electron current was effectively suppressed to the ratio of Ie/I{sub D}- <1. The highest energy beam of 460 keV, 2.4 A, 0.44 s has also been obtained. Neutral beam injection starts in March, 1996 using two ion sources. To realize 1 MeV class NBI system for ITER (International Thermonuclear Experimental Reactor), demonstration of ampere class negative ion beam acceleration up to 1 MeV is an important mile stone. To achieve the mile stone, a high energy test facility called MeV Test Facility (MTF) was constructed. The system consists of a 1 MV, 1 A acceleration power supply and a 100 kW power supply system for negative ion production. Up to now, an H{sup -} ion beam was accelerated up to the energy of 805 keV with an acceleration drain current of 150 mA for 1 s in a five stage electrostatic multi-aperture accelerator. (author)

  15. Attainment of high confinement in neutral beam heated divertor discharges in the PDX tokamak

    International Nuclear Information System (INIS)

    The PDX divertor configuration has recently been converted from an open to a closed geometry to inhibit the return of neutral gas from the divertor region to the main chamber. Since then, operation in a regime with high energy confinement in neutral beam heated discharges (ASDEX H-mode) has been routine over a wide range of operating conditions. These H-mode discharges are characterized by a sudden drop in divertor density and H/sub α/ emission and a spontaneous rise in main chamber plasma density during neutral beam injection. The confinement time is found to scale nearly linearly with plasma current, but it can be degraded due to either the presence of edge instabilities or heavy gas puffing. Detailed Thomson scattering temperature profiles show high values of Te near the plasma edge (approx. 450 eV) with sharp radial gradients (approx. 400 eV/cm) near the separatrix. Density profiles are broad and also exhibit steep gradients close to the separatrix

  16. 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

  17. Burnout experiments on the externally-finned swirl tube for steady-state and high-heat flux beam stops

    International Nuclear Information System (INIS)

    An experimental study to develop beam stops for the next generation of neutral beam injectors was started, using an ion source developed for the JT-60 neutral beam injector. A swirl tube is one of the most promising candidates for a beam stop element which can handle steady-state and high-heat flux beams. In the present experiments, a modified swirl tube, namely an externally-finned swirl tube, was tested together with a simple smooth tube, an externally finned tube, and an internally finned tube. The major dimensions of the tubes are 10 mm in outer-diameter, 1.5 mm in wall thickness, 15 mm in external fin width, and 700 mm in length. The burnout heat flux (CHF) normal to the externally finned swirl tube was 4.1±0.1 kW/cm2, where the Gaussian e-folding half-width of the beam intensity distribution was about 90 mm, the flow rate of the cooling water was 30 l/min, inlet and outlet gauge pressures were about 1 MPa and 0.2 MPa, respectively, and the temperature of the inlet water was kept to 200C during a pulse. A burnout heat flux ratio, which is defined by the ratio of the CHF value of the externally-finned swirl tube to that of the externally-finned tube, turned out to be about 1.5. Burnout heat fluxes of the tubes with a swirl tape or internal fins increase linearly with an increase of the flow rate. It was found that the tube with external fins has effects that not only reduce the thermal stress but also improve the characteristics of boiling heat transfer. (orig.)

  18. Pyramid beam splitter

    Science.gov (United States)

    McKeown, Mark H.; Beason, Steven C.; Fairer, George

    1992-01-01

    The apparatus of the present invention provides means for obtaining accurate, dependable, measurement of bearings and directions for geologic mapping in subterranean shafts, such as, for example, nuclear waste storage investigations. In operation, a laser beam is projected along a reference bearing. A pyramid is mounted such that the laser beam is parallel to the pyramid axis and can impinge on the apex of the pyramid thus splitting the beam several ways into several beams at right angles to each other and at right angles to the reference beam. The pyramid is also translatable and rotatable in a plane perpendicular to the reference beam.

  19. Low current beam techniques

    Energy Technology Data Exchange (ETDEWEB)

    Saint, A.; Laird, J.S.; Bardos, R.A.; Legge, G.J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Nishijima, T.; Sekiguchi, H. [Electrotechnical Laboratory, Tsukuba (Japan).

    1993-12-31

    Since the development of Scanning Transmission Microscopy (STIM) imaging in 1983 many low current beam techniques have been developed for the scanning (ion) microprobe. These include STIM tomography, Ion Beam Induced Current, Ion Beam Micromachining and Microlithography and Ionoluminense. Most of these techniques utilise beam currents of 10{sup -15} A down to single ions controlled by beam switching techniques This paper will discuss some of the low beam current techniques mentioned above, and indicate, some of their recent applications at MARC. A new STIM technique will be introduced that can be used to obtain Z-contrast with STIM resolution. 4 refs., 3 figs.

  20. Energy Transport Effects in Flaring Atmospheres Heated by Mixed Particle Beams

    Science.gov (United States)

    Zharkova, Valentina; Zharkov, Sergei; Macrae, Connor; Druett, Malcolm; Scullion, Eamon

    2016-07-01

    We investigate energy and particle transport in the whole flaring atmosphere from the corona to the photosphere and interior for the flaring events on the 1st July 2012, 6 and 7 September 2011 by using the RHESSI and SDO instruments as well as high-resolution observations from the Swedish 1-metre Solar Telescope (SST3) CRISP4 (CRisp Imaging Spectro-polarimeter). The observations include hard and soft X-ray emission, chromospheric emission in both H-alpha 656.3 nm core and continuum, as well as, in the near infra-red triplet Ca II 854.2 nm core and continuum channels and local helioseismic responses (sunquakes). The observations are compared with the simulations of hard X-ray emission and tested by hydrodynamic simulations of flaring atmospheres of the Sun heated by mixed particle beams. The temperature, density and macro-velocity variations of the ambient atmospheres are calculated for heating by mixed beams and the seismic response of the solar interior to generation of supersonic shocks moving into the solar interior. We investigate the termination depths of these shocks beneath the quiet photosphere levels and compare them with the parameters of seismic responses in the interior, or sunquakes (Zharkova and Zharkov, 2015). We also present an investigation of radiative conditions modelled in a full non-LTE approach for hydrogen during flare onsets with particular focus on Balmer and Paschen emission in the visible, near UV and near IR ranges and compare them with observations. The links between different observational features derived from HXR, optical and seismic emission are interpreted by different particle transport models that will allow independent evaluation of the particle transport scenarios.

  1. Beam Dynamics and Beam Losses - Circular Machines

    CERN Document Server

    Kain, V

    2016-01-01

    A basic introduction to transverse and longitudinal beam dynamics as well as the most relevant beam loss mechanisms in circular machines will be presented in this lecture. This lecture is intended for physicists and engineers with little or no knowledge of this subject.

  2. Beam-beam issues in asymmetric colliders

    Energy Technology Data Exchange (ETDEWEB)

    Furman, M.A.

    1992-07-01

    We discuss generic beam-beam issues for proposed asymmetric e{sup +}- e{sup -} colliders. We illustrate the issues by choosing, as examples, the proposals by Cornell University (CESR-B), KEK, and SLAC/LBL/LLNL (PEP-II).

  3. Equation of state studies of warm dense matter samples heated by laser produced proton beams

    Science.gov (United States)

    Hoarty, D. J.; Guymer, T.; James, S. F.; Gumbrell, E.; Brown, C. R. D.; Hill, M.; Morton, J.; Doyle, H.

    2012-03-01

    Heating of matter by proton beams produced by short pulse, laser-solid target interaction has been demonstrated over the last ten years by a number of workers. In the work described in this paper heating by a pulse of laser produced protons has been combined with high-resolution soft x-ray radiography to record the expansion of thin wire targets. Analysis of the radiographs yields material properties in the warm dense matter regime. These measurements imply initial temperatures in the experimental samples over a range from 14 eV up to 40 eV; the sample densities varied from solid to a tenth solid density. Assuming an adiabatic expansion after the initial proton heating phase isentropes of the aluminium sample material were inferred and compared to tabulated data from the SESAME equation of state library. The proton spectrum was also measured using calibrated magnetic spectrometers and radiochromic film. The accuracy of the technique used to infer material data is discussed along with possible future development.

  4. Tube to tubesheet welding by electron beam for heat exchanger application

    International Nuclear Information System (INIS)

    The EB-process can successfully be used to weld in tubes into tubesheet also for those materials which are sensitiv to hot cracking. The range of qualified welding parameters has been evaluated based on a lot of metallographic and microanalysis inspections. To obtain reproducable and perfect welds a microcomputer controlled welding cycle is recommended using beam deflection, automatic seam tracking, beam current- and focus control. The results can be adopted to the specific conditions of mobile welding equipment with local vacuum. (orig.)

  5. Laser-Beam Separator

    Science.gov (United States)

    Mcdermid, I. S.

    1984-01-01

    Train of prisms and optical stop separate fundamental beam of laser from second and higher order harmonics of beam produced in certain crystals and by stimulated Raman scattering in gases and liquids.

  6. Beam Loss in Linacs

    CERN Document Server

    Plum, M A

    2016-01-01

    Beam loss is a critical issue in high-intensity accelerators, and much effort is expended during both the design and operation phases to minimize the loss and to keep it to manageable levels. As new accelerators become ever more powerful, beam loss becomes even more critical. Linacs for H- ion beams, such as the one at the Oak Ridge Spallation Neutron Source, have many more loss mechanisms compared to H+ (proton) linacs, such as the one being designed for the European Spallation Neutron Source. Interesting H- beam loss mechanisms include residual gas stripping, H+ capture and acceleration, field stripping, black-body radiation and the recently discovered intra-beam stripping mechanism. Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H+ and H- accelerators. Machine protection systems play an important role in limiting the beam loss.

  7. Space charge dominated beams

    International Nuclear Information System (INIS)

    After an introductory section on the relationship between emittance and beam Coulomb energy we discuss the properties of space charge dominated beams in progressive steps: from uniformly charged bunched beams to non-uniformly charged beams to correlation effects between particles (simulation beams or 'crystalline' beams). A practical application can be found in the beam dynamics of a high-current injector. The concept of correlation energy is of practical interest in computer simulation of high-brilliance beams, where one deals with an artificially enhanced two-particle Coulomb energy, if many real particles are combined into one simulation super-particle. This can be a source of non-physical emittance growth. (orig./HSI)

  8. High energy beam lines

    Science.gov (United States)

    Marchetto, M.; Laxdal, R. E.

    2014-01-01

    The ISAC post accelerator comprises an RFQ, DTL and SC-linac. The high energy beam lines connect the linear accelerators as well as deliver the accelerated beams to two different experimental areas. The medium energy beam transport (MEBT) line connects the RFQ to the DTL. The high energy beam transport (HEBT) line connects the DTL to the ISAC-I experimental stations (DRAGON, TUDA-I, GPS). The DTL to superconducting beam (DSB) transport line connects the ISAC-I and ISAC-II linacs. The superconducting energy beam transport (SEBT) line connects the SC linac to the ISAC-II experimental station (TUDA-II, HERACLES, TIGRESS, EMMA and GPS). All these lines have the function of transporting and matching the beams to the downstream sections by manipulating the transverse and longitudinal phase space. They also contain diagnostic devices to measure the beam properties.

  9. Comparison of the Performance of Chilled Beam with Swirl Jet and Diffuse Ceiling Air Supply: Impact of Heat Load Distribution

    DEFF Research Database (Denmark)

    Bertheussen, Bård; Mustakallio, Panu; Kosonen, Risto;

    2013-01-01

    The impact of heat load strength and positioning on the indoor environment generated by diffuse ceiling air supply and chilled beam with radial swirl jet was studied and compared. An office room with two persons and a meeting room with six persons were simulated in a test room (4.5 x 3.95 x 3.5 m3...

  10. Recent progress of high-power negative ion beam development for fusion plasma heating

    Science.gov (United States)

    Watanabe, Kazuhiro; Akino, Noboru; Aoyagi, Tetsuo; Ebisawa, Noboru; Fujiwara, Yukio; Honda, Atsusi; Inoue, Takashi; Itoh, Takao; Kawai, Mikito; Kazawa, Minoru; Koizumi, Junichi; Kuriyama, Masaaki; Miyamoto, Kenji; Miyamoto, Naoki; Mogaki, Kazuhiko; Ohara, Yoshihiro; Ohga, Tokumichi; Okumura, Yoshikazu; Oohara, Hiroshi; Ohshima, Katsumi; Satoh, Fujio; Shimizu, Kazuhiko; Takahashi, Syunji; Usami, Hirotsugu; Usui, Katsutomi; Yamamoto, Masahiro; Yamazaki, Takeshi

    1997-06-01

    A negative-ion-based neutral beam injector (N-NBI) has been constructed for JT-60U. The N-NBI is designed to inject 500 keV, 10 MW neutral beams using two ion sources, each producing a 500 keV, 22 A D - ion beam. In the preliminary experiment using one ion source, a D - ion beam of 13.5 A has been successfully accelerated with an energy of 400 keV (5.4 MW) for 0.12 s at an operating pressure of 0.22 Pa. This is the highest D - beam current and power in the world. Co-extracted electron current was effectively suppressed to the ratio of Ie/ ID - mile stone. To achieve the mile stone, a prototype accelerator and a 1 MV, 1 A test facility called MeV Test Facility (MTF) were constructed. Up to now, an H - ion beam was accelerated up to the energy of 805 keV with an acceleration drain current of 150 mA for 1 s in a five stage electrostatic multi-aperture accelerator.

  11. Proton beam writing

    OpenAIRE

    Frank Watt; Breese, Mark B H; Bettiol, Andrew A; Jeroen A. van Kan

    2007-01-01

    Proton beam (p-beam) writing is a new direct-writing process that uses a focused beam of MeV protons to pattern resist material at nanodimensions. The process, although similar in many ways to direct writing using electrons, nevertheless offers some interesting and unique advantages. Protons, being more massive, have deeper penetration in materials while maintaining a straight path, enabling p-beam writing to fabricate three-dimensional, high aspect ratio structures with vertical, smooth side...

  12. Welding by laser beam

    International Nuclear Information System (INIS)

    A laser which does not require a vacuum and the beam from which can be projected over a distance without loss of power is sited outside a welding zone and the beam projected through a replaceable laser transparent window. The window is designed and shaped to facilitate access of the beam of workpiece items to be welded in containment. Either the workpiece or the laser beam may be moved during welding. (author)

  13. Slow kaon beams

    International Nuclear Information System (INIS)

    A short description is given of considerations for the design of low-momentum kaon beam lines. Relevant data for the performance of seven existing and decommissioned slow kaon beams are presented. For single-stage separated beams the observed ratio all/K- is greater than 50 for momenta less than 500 MeV/c. We recommend a two-stage separated beam with perhaps an upstream cleanup section for maximal purity

  14. Beam Dynamics for ARIA

    CERN Document Server

    Ekdahl, Carl

    2015-01-01

    Beam dynamics issues are assessed for a new linear induction electron accelerator being designed for flash radiography of large explosively driven hydrodynamic experiments. Special attention is paid to equilibrium beam transport, possible emittance growth, and beam stability. It is concluded that a radiographic quality beam will be produced possible if engineering standards and construction details are equivalent to those on the present radiography accelerators at Los Alamos.

  15. PARTICLE BEAM TRACKING CIRCUIT

    Science.gov (United States)

    Anderson, O.A.

    1959-05-01

    >A particle-beam tracking and correcting circuit is described. Beam induction electrodes are placed on either side of the beam, and potentials induced by the beam are compared in a voltage comparator or discriminator. This comparison produces an error signal which modifies the fm curve at the voltage applied to the drift tube, thereby returning the orbit to the preferred position. The arrangement serves also to synchronize accelerating frequency and magnetic field growth. (T.R.H.)

  16. Electron beam focusing system

    Energy Technology Data Exchange (ETDEWEB)

    Dikansky, N.; Nagaitsev, S.; Parkhomchuk, V.

    1997-09-01

    The high energy electron cooling requires a very cold electron beam. Thus, the electron beam focusing system is very important for the performance of electron cooling. A system with and without longitudinal magnetic field is presented for discussion. Interaction of electron beam with the vacuum chamber as well as with the background ions and stored antiprotons can cause the coherent electron beam instabilities. Focusing system requirements needed to suppress these instabilities are presented.

  17. Beam Dynamics for ARIA

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl August Jr. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-10-14

    Beam dynamics issues are assessed for a new linear induction electron accelerator being designed for flash radiography of large explosively driven hydrodynamic experiments. Special attention is paid to equilibrium beam transport, possible emittance growth, and beam stability. It is concluded that a radiographic quality beam will be produced possible if engineering standards and construction details are equivalent to those on the present radiography accelerators at Los Alamos.

  18. Preliminary Results of Ion Beam Extraction Tests on EAST Neutral Beam Injector

    Institute of Scientific and Technical Information of China (English)

    胡纯栋

    2012-01-01

    The neutral beam injection (NBI) system is one of the most important auxiliary plasma heating and current driving methods for fusion device. A high power ion beam of 3 MW with 80 keV beam energy in 0.5 s beam duration and a long pulse ion beam of 4 s with 50 keV beam energy ion beam extraction were achieved on the EAST neutral beam injector on the teststand. The preliminary results show that the EAST-NBI system was developed successfully on schedule.

  19. Beams 92: Proceedings

    International Nuclear Information System (INIS)

    This report contains papers on the following topics: Ion beam papers; electron beam, bremsstrahlung, and diagnostics papers; radiating Z- pinch papers; microwave papers; electron laser papers; advanced accelerator papers; beam and pulsed power applications papers; pulsed power papers; and these papers have been indexed separately elsewhere

  20. Accelerating nondiffracting beams

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Shaohui; Li, Manman; Yao, Baoli, E-mail: yaobl@opt.ac.cn; Yu, Xianghua; Lei, Ming; Dan, Dan; Yang, Yanlong; Min, Junwei; Peng, Tong

    2015-06-05

    We present a set of beams which combine the properties of accelerating beams and (conventional) diffraction-free beams. These beams can travel along a desired trajectory while keeping an approximately invariant transverse profile, which may be (higher-order) Bessel-, Mathieu- or parabolic-nondiffracting-like beams, depending on the initial complex amplitude distribution. A possible application of these beams presented here may be found in optical trapping field. For example, a higher-order Bessel-like beam, which has a hollow (transverse) pattern, is suitable for guiding low-refractive-index or metal particles along a curve. - Highlights: • A set of beams having arbitrary trajectories of accelerating and nondiffracting behaviors are generalized and presented. • Bessel-like accelerating beams are generalized to the higher-order (hollow) version. • Mathieu-like accelerating beams and parabolic-nondiffracting-like accelerating beams are presented. • A possible application of these beams may be found in optical trapping and guiding of particles.

  1. An Electromagnetic Beam Converter

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to an electromagnetic beam converter and a method for conversion of an input beam of electromagnetic radiation having a bell shaped intensity profile a(x,y) into an output beam having a prescribed target intensity profile l(x',y') based on a further development...

  2. Klystron beam bunching

    International Nuclear Information System (INIS)

    A detailed description of electron-beam bunching phenomena in klystrons is presented. Beam harmonic current is defined, both space-charge and ballistic bunching are analyzed, Ramo's theorem is used to describe how a bunched beam drives a cavity, and a general cavity model including external coupling is provided. (author)

  3. Carbon doping in molecular beam epitaxy of GaAs from a heated graphite filament

    Science.gov (United States)

    Malik, R. J.; Nottenberg, R. N.; Schubert, E. F.; Walker, J. F.; Ryan, R. W.

    1988-01-01

    Carbon doping of GaAs grown by molecular beam epitaxy has been obtained for the first time by use of a heated graphite filament. Controlled carbon acceptor concentrations over the range of 10 to the 17th-10 to the 20th/cu cm were achieved by resistively heating a graphite filament with a direct current power supply. Capacitance-voltage, p/n junction and secondary-ion mass spectrometry measurements indicate that there is negligible diffusion of carbon during growth and with postgrowth rapid thermal annealing. Carbon was used for p-type doping in the base of Npn AlGaAs/GaAs heterojunction bipolar transistors. Current gains greater than 100 and near-ideal emitter heterojunctions were obtained in transistors with a carbon base doping of 1 x 10 to the 19th/cu cm. These preliminary results indicate that carbon doping from a solid graphite source may be an attractive substitute for beryllium, which is known to have a relatively high diffusion coefficient in GaAs.

  4. Surface modification of molten W exposed to high heat flux helium neutral beams

    International Nuclear Information System (INIS)

    High heat flux tests with central heat flux of 10.5 MW/m2 using helium neutral beams have been carried out on rolled tungsten. The energy of helium particles is 33 keV and the particle flux is 2 × 1021 m−2 s−1. An 80 × 65 × 3 mm3 rolled tungsten plate is firstly exposed to a 4.6 s pulse resulting in partially molten surfaces. Thereafter the tungsten plate is irradiated by several helium pulses with fluences of 1.2–2.5 × 1022/m2 and peak temperatures from 1450 to 2590 °C. The experiments show that: (1) helium-induced surface modification of the resolidified tungsten surface is very different from that of the non-molten surface; (2) the surface morphology of molten surface is closely related to the orientation of the resolidified grain; (3) the evolution of surface modifications, for both of the molten and non-molten tungsten surfaces, indicates a strong dependence on the surface temperature and local helium fluence

  5. Pushing the limits - beam

    CERN Document Server

    Métral, E

    2011-01-01

    Many collective effects were observed in 2010, first when the intensity per bunch was increased and subsequently when the number of bunches was pushed up and the bunch spacing was reduced. After a review of the LHC performance during the 2010 run, with a particular emphasis on impedances and related single-beam coherent instabilities, but mentioning also beam-beam and electron cloud issues, the potential of the LHC for 2011 will be discussed. More specifically, the maximum bunch/beam intensity and the maximum beam brightness the LHC should be able to swallow will be compared to what the injectors can provide.

  6. Cluster ion beam evaporation

    International Nuclear Information System (INIS)

    Cluster ions can be made by the supercooling due to adiabatic expansion of substances to be vaporized which are ejected from a nozzle. This paper is described on the recent progress of studies concerning the cluster beam. The technique of cluster ion beam has been applied for the studies of thermonuclear plasma, the fabrication of thin films, crystal growth and electronic devices. The density of cluster ion beam is larger than that of atomic ion beam, and the formation of thin films can be easily done in high vacuum. This method is also useful for epitaxial growth. Metallic vapour cluster beam was made by the help of jetting rare gas beam. Various beam sources were developed. The characteristics of these sources were measured and analyzed. (Kato, T.)

  7. Thermal Buckling and Free Vibration Analysis of Heated Functionally Graded Material Beams

    Directory of Open Access Journals (Sweden)

    Khalane Sanjay Anandrao

    2013-05-01

    Full Text Available The effect of temperature dependency of material properties on thermal buckling and free vibration of functionally graded material (FGM beams is studied. The FGM beam is assumed to be at a uniform through thickness temperature, above the ambient temperature. Finite element system of equations based on the first order shear deformation theory is developed. FGM beam with axially immovable ends having the classical boundary conditions is analysed. An exhaustive set of numerical results, in terms of buckling temperatures and frequencies, is presented, considering the temperature independent and temperature dependent material properties. The buckling temperature and fundamental frequency obtained using the temperature independent material properties is higher than that obtained by using the temperature dependent material properties, for all the material distributions, geometrical parameters in terms of length to thickness ratios and the boundary conditions considered. It is also observed that the frequencies of the FGM beam will reduce with the increase in temperature. This observation is applicable for the higher modes of vibration also. The necessity of considering the temperature dependency of material properties in determining thermal buckling and vibration characteristics of FGM beams is clearly demonstrated.Defence Science Journal, 2013, 63(3, pp.315-322, DOI:http://dx.doi.org/10.14429/dsj.63.2370

  8. Laser Beam Failure Mode Effects and Analysis (FMEA) of the Solid State Heat Capacity Laser (SSHCL)

    Energy Technology Data Exchange (ETDEWEB)

    King, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-09-07

    A laser beam related FMEA of the SSHCL was performed to determine potential personnel and equipment safety issues. As part of the FMEA, a request was made to test a sample of the drywall material used for walls in the room for burn-through. This material was tested with a full power beam for five seconds. The surface paper material burned off and the inner calcium carbonate turned from white to brown. The result of the test is shown in the photo below.

  9. Evaluation of electron beam irradiation under heating process on vulcanized EPDM

    Energy Technology Data Exchange (ETDEWEB)

    Gabriel, Leandro; Cardoso, Jessica R.; Moura, Eduardo; Geraldo, Aurea B.C., E-mail: lgabriell@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    The Global consumption of rubber is estimated around 30.5 million tons in 2015, when it is expected an increase of 4.3% of this volume in the coming of years. This demand is mainly attributed to the production of elastomeric accessories for the automotive sector. However, the generation of this type of waste also reaches major proportions at the end of its useful life, when it is necessary to dispose the environmental liability. Rubber reprocessing is an alternative where it can be used as filler in other polymer matrices or in other types of materials. The devulcanization process is another alternative and it includes the study of methods that allow economic viability and waste reduction. Therefore, this study aims to recycle vulcanized EPDM rubber with the use of ionizing radiation. In this work we are using the electron beam irradiation process with simultaneous heating at absorbed doses from 150 kGy to 800 kGy, under high dose rate of 22.3 kGy/s on vulcanized EPDM powder and on samples about 4 mm thick. Their characterization, before and after the irradiation process, have been realized by thermal analysis and their changes have been discussed. (author)

  10. Colliding Crystalline Beams

    International Nuclear Information System (INIS)

    The understanding of crystalline beams has advanced to the point where one can now, with reasonable confidence, undertake an analysis of the luminosity of colliding crystalline beams. Such a study is reported here. It is necessary to observe the criteria, previously stated, for the creation and stability of crystalline beams. This requires, firstly, the proper design of a lattice. Secondly, a crystal must be formed, and this can usually be done at various densities. Thirdly, the crystals in a colliding-beam machine are brought into collision. We study all of these processes using the molecular dynamics (MD) method. The work parallels what was done previously, but the new part is to study the crystal-crystal interaction in collision. We initially study the zero-temperature situation. If the beam-beam force (or equivalent tune shift) is too large then over-lapping crystals can not be created (rather two spatially separated crystals are formed). However, if the beam-beam force is less than but comparable to that of the space-charge forces between the particles, we find that overlapping crystals can be formed and the beam-beam tune shift can be of the order of unity. Operating at low but non-zero temperature can increase the luminosity by several orders of magnitude over that of a usual collider. The construction of an appropriate lattice, and the development of adequately strong coding, although theoretically achievable, is a challenge in practice

  11. Preliminary Experimental Study of Ion Beam Extraction of EAST Neutral Beam Injector

    Institute of Scientific and Technical Information of China (English)

    XU Yong-Jian; HU Chun-Dong; LIU Sheng; XIE Ya-Hong; LIANG Li-Zhen; JIANG Cai-Chao

    2012-01-01

    Neutral beam injection is recognized as one of the most effective means for plasma heating.The preliminary data of ion beam extraction is obtained on the EAST neutral beam injector test-stand.Beam extraction from the ion source of EAST-NBI is verified by measuring the beam current with a Faraday cup and by analyzing the results obtained by means of water calorimetric measurement on the temperature rises of water cooling the accelerator electrodes.

  12. Beam-beam effect seen through forced vibration

    International Nuclear Information System (INIS)

    In electron accelerator, tune is measured by giving beam transverse forced vibration caused by RF frequency. It is well known that beam-beam parameter can be measured if beam-beam interaction exists. Generally, small value is chosen as the amplitude of forced vibration, and many researches were done in this case. In this report, we discuss effect of resonance caused by beam-beam interaction in case of amplitude of forced vibration being big. (author)

  13. Beam instability studies for the SSC

    Energy Technology Data Exchange (ETDEWEB)

    Chou, W.

    1994-09-01

    Beam instability studies of the Superconducting Super Collider (SSC) during the period 1989--1993 are briefly reviewed in this paper. Various topics are covered: single bunch and multi-bunch, single beam and beam-beam, parasitic heating and active feedback, etc. Although the SSC will not be built, many of the results obtained from these studies remain as useful references to the accelerator community.

  14. Modeling of plasma heating with neutral beam injection in T-11 machine

    International Nuclear Information System (INIS)

    Computations of energy balance are presented for a tokamak with hot atom beam injection. Atom ionization, trapping of generated ions and energy transfer to plasma are examined. Energy loss in charge exchange is considered. Relationships are presented between the temperature and the injection power, the plasma density and other parameters. Possibilities are discussed for obtaining a collisionless ion regime

  15. KEKB beam instrumentation systems

    Science.gov (United States)

    Arinaga, M.; Flanagan, J.; Hiramatsu, S.; Ieiri, T.; Ikeda, H.; Ishii, H.; Kikutani, E.; Mimashi, T.; Mitsuhashi, T.; Mizuno, H.; Mori, K.; Tejima, M.; Tobiyama, M.

    2003-02-01

    For the stable high-luminosity operation and luminosity increase, the electron and positron storage rings of the KEK B-Factory (KEKB) is equipped with various beam instrumentations, which have been working well since the start of the commissioning in December, 1998. Details and performance of the beam-position monitor system based on the spectrum analysis using DSPs, the turn-by-turn BPM with four-dimensional function available for measurements of the individual bunch position, phase and intensity, the parametric beam-DCCTs designed so as to avoid the magnetic-core-selection problems for the parametric flux modulation, the bunch-by-bunch feedback system indispensable to suppress the strong multibunch instabilities in KEKB, the various optical beam diagnostic systems, such as synchrotron radiation interferometers for precise beam-size measurement, the tune meters, the bunch length monitors and the beam-loss monitors are described. Delicate machine tuning of KEKB is strongly supported by these instrumentations.

  16. Proton Beam Energy Characterization

    OpenAIRE

    Marus, Lauren A.; Engle, J.W.; John, K. D.; Birnbaum, E. R.; Nortier, F. M.

    2015-01-01

    Introduction The Los Alamos Isotope Production Facility (IPF) is actively engaged in the development of isotope production technologies that can utilize its 100 MeV proton beam. Characterization of the proton beam energy and current is vital for optimizing isotope production and accurately conducting research at the IPF. Motivation In order to monitor beam intensity during research irradiations, aluminum foils are interspersed in experimental stacks. A theoretical yield of 22Na from...

  17. Hyperon beam physics

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, P.S.

    1996-03-01

    This report reviews the present status and recent results in hyperon physics concentrating on results from high energy hyperon beam experiments performed at Fermilab over the past several years. The report focuses on hyperon production polarization, precision hyperon magnetic moment measurements and radiative decay studies. Modern charged hyperon beam experiments are characterized by {approx}100m long apparatus and hyperon beams with {gamma}{sub Y}{approx}100 and hyperon fluxes in the 1-100 kHz range.

  18. Semiconductor laser beam bending

    OpenAIRE

    YILDIRIM, REMZİ; ÇELEBİ, FATİH VEHBİ

    2015-01-01

    This study is about a single-component cylindrical structured lens with a gradient curve that was used for bending laser beams. It operates under atmospheric conditions and bends the laser beam independently of temperature, pressure, polarity, polarization, magnetic field, electric field, radioactivity, and gravity. A single-piece cylindrical lens that can bend laser beams was developed. Lenses are made of transparent, tinted, or colored glass and are used to undermine or absorb the energy of...

  19. Mechanical beam isolator

    International Nuclear Information System (INIS)

    Back-reflections from a target, lenses, etc. can gain energy passing backwards through a laser just like the main beam gains energy passing forwards. Unless something blocks these back-reflections early in their path, they can seriously damage the laser. A Mechanical Beam Isolator is a device that blocks back-reflections early, relatively inexpensively, and without introducing aberrations to the laser beam

  20. Resolving Two Beams in Beam Splitters with a Beam Position Monitor

    Science.gov (United States)

    Kurennoy, Sergey

    2002-04-01

    The beam transport system for the Advanced Hydrotest Facility (AHF) anticipates multiple beam splitters. Monitoring two transversely separated beams in a common beam pipe in the splitter sections imposes certain requirements on beam diagnostics for these sections. We explore a two-beam system in a generic beam monitor and study the feasibility of resolving the transverse positions of the two beams with one diagnostics device. Effects of unequal beam currents and of finite transverse sizes of the beams are explored analytically for both the ultra relativistic case and the long-wavelength limit.

  1. Beam cavity interaction

    CERN Document Server

    Gamp, A

    2011-01-01

    We begin by giving a description of the rf generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, rf feedback, and feed-forward are described. Examples of digital rf phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  2. Beam alignment system

    International Nuclear Information System (INIS)

    A patent is claimed for the invention of a beam alignment system. The aim of the invention is the obtention of an accurate monitoring of the beam position and direction. It is of great interest in the nuclear industry. The invention can be applied in an infrared laser beam for welding operations. An auxiliar radiation source is incorporated to the device. The system's configuration allows a simultaneous and separated utilisation of two beams. The description and the design of the proposed system are provided

  3. Simulating Transient Effects of Pulsed Beams on Beam Intercepting Devices

    CERN Document Server

    Richter, Herta; Noah Messomo, Etam

    2011-01-01

    The development in the physics community towards higher beam power through the possibilities of particle accelerators lead to challenges for the developers of elements which are exposed to effect of particle beams (beam intercepting devices = BIDs). For the design of BIDs, the increasing heat load onto these devices due to energetic and focused beams and - in most cases - their highly pulsed nature has to be taken into account. The physics requirements are sometimes opposed to the current state of the art. As one possibility of many in combining the different aspects for these ambitious demands, two highly developed computer programs, namely FLUKA and ANSYS AUTODYN, were joined for this dissertation. The former is a widely enhanced Monte-Carlo-code which specializes on the interaction of particles with static matter, while the latter is a versatile explicit code for the simulation of highly dynamic processes. Both computer programs were developed intensively over years and are still continuously enhanced in o...

  4. A computer code for computing the beam profiles in the NBI beam line 'BEMPROF'

    International Nuclear Information System (INIS)

    A computer code was developed which can compute the beam profiles and the percentage heat loadings on the various components in the NBI beam line such as the beam target, the beam limiters and the calorimeter. The geometrical injection efficiency of NBI and the heat input pattern on the counter surface of the injection port of the torus can also be computed. The major feature of this code is that the effects of the beamlet intensity distribution, the beamlet deflection, the beam screening by the upstream limiters and also the plasma density distribution and the divergence angle distribution over the beam extraction area can be taken into account. (author)

  5. Primary resonance of lateral vibration of a heated beam with an axial stick-slip-stop boundary

    Science.gov (United States)

    Cui, D. F.; Hu, H. Y.

    2015-03-01

    As a first endeavor, the present work deals with the primary resonance of lateral vibration of an Euler-Bernoulli beam with a sliding end and under both uniformly distributed heating and harmonic loads. The sliding end is subject to a pair of adjustable normal force and frictional force such that it is initially at a stick status, but may be slightly slipping due to the thermal expansion of the beam until it contacts a stop, i.e., the bound of the clearance. Moreover, this sliding end may also be slipping during the lateral vibration when the vibration amplitude is larger than a critical value. Firstly, based on the nonlinear relation between strain and displacement, a set of partial differential equations of the beam and the axial boundary condition for the sliding end are derived by utilizing Hamilton's principle, where both frictional force and temperature-dependent properties of material are taken into consideration. Then, Galerkin's approach is employed to simplify the partial differential equations to a set of ordinary differential equations. Subsequently, the average approach is used to determine the steady-state primary resonance. Finally, the analytical solutions are well verified through numerical simulations and the influences of system parameters, such as temperature rise and normal force, on the primary resonance of lateral vibration of the beam are discussed. The study shows that it is possible to adjust the primary resonance of lateral vibration of the heated beam with an axial stick-slip-stop boundary via the analytical solutions, which involve the normal force, the clearance and the temperature rise.

  6. Simulation of Beam-Beam Background at CLIC

    CERN Document Server

    Sailer, A

    2010-01-01

    The dense beams used at CLIC to achieve a high luminosity will cause a large amount of background particles through beam-beam interactions. Generator level studies with GUINEAPIG and full detector simulation studies with an ILD based CLIC detector have been performed to evaluate the amount of beam-beam back- ground hitting the vertex detector.

  7. Resolving Two Beams in Beam Splitters with a Beam Position Monitor

    CERN Document Server

    Kurennoy, S S

    2002-01-01

    The beam transport system for the Advanced Hydrotest Facility (AHF) anticipates multiple beam splitters [1]. Monitoring two separated beams in a common beam pipe in the splitter sections imposes certain requirements on diagnostics for these sections. In this note we explore a two-beam system in a generic beam monitor and study the feasibility of resolving the positions of the two beams with a single diagnostic device.

  8. Neutral beams for magnetic fusion

    International Nuclear Information System (INIS)

    Significant advances in forming energetic beams of neutral hydrogen and deuterium atoms have led to a breakthrough in magnetic fusion: neutral beams are now heating plasmas to thermonuclear temperatures, here at LLL and at other laboratories. For example, in our 2XIIB experiment we have injected a 500-A-equivalent current of neutral deuterium atoms at an average energy of 18 keV, producing a dense plasma (1014 particles/cm3) at thermonuclear energy (14 keV or 160 million kelvins). Currently, LLL and LBL are developing beam energies in the 80- to 120-keV range for our upcoming MFTF experiment, for the TFTR tokamak experiment at Princeton, and for the Doublet III tokamak experiment at General Atomic. These results increase our long-range prospects of producing high-intensity beams of energies in the hundreds or even thousands of kilo-electron-volts, providing us with optimistic extrapolations for realizing power-producing fusion reactors

  9. Electron beam diagnostic for profiling high power beams

    Science.gov (United States)

    Elmer, John W.; Palmer, Todd A.; Teruya, Alan T.

    2008-03-25

    A system for characterizing high power electron beams at power levels of 10 kW and above is described. This system is comprised of a slit disk assembly having a multitude of radial slits, a conducting disk with the same number of radial slits located below the slit disk assembly, a Faraday cup assembly located below the conducting disk, and a start-stop target located proximate the slit disk assembly. In order to keep the system from over-heating during use, a heat sink is placed in close proximity to the components discussed above, and an active cooling system, using water, for example, can be integrated into the heat sink. During use, the high power beam is initially directed onto a start-stop target and after reaching its full power is translated around the slit disk assembly, wherein the beam enters the radial slits and the conducting disk radial slits and is detected at the Faraday cup assembly. A trigger probe assembly can also be integrated into the system in order to aid in the determination of the proper orientation of the beam during reconstruction. After passing over each of the slits, the beam is then rapidly translated back to the start-stop target to minimize the amount of time that the high power beam comes in contact with the slit disk assembly. The data obtained by the system is then transferred into a computer system, where a computer tomography algorithm is used to reconstruct the power density distribution of the beam.

  10. Damping of a vibrating beam

    NARCIS (Netherlands)

    Hietanen, Jarmo; Bomer, Johan; Jonsmann, Jacques; Olthuis, Wouter; Bergveld, Piet; Kaski, Kimmo

    2000-01-01

    This study examines the vibration in a beam with one fixed end. The set-up consisted of a beam with one end clamped and a rigid plate having the same thickness of the beam, located adjacent to the unfixed end of the beam. The gap between the beam and the plate varied from 4 to 128 μm depending on th

  11. ION BEAM HEATED TARGET SIMULATIONS FOR WARM DENSE MATTER PHYSICS AND INERTIAL FUSION ENERGY

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, J.J.; Armijo, J.; Bailey, D.S.; Friedman, A.; Bieniosek, F.M.; Henestroza, E.; Kaganovich, I.; Leung, P.T.; Logan, B.G.; Marinak, M.M.; More, R.M.; Ng, S.F.; Penn, G.E.; Perkins, L.J.; Veitzer, S.; Wurtele, J.S.; Yu, S.S.; Zylstra, A.B.

    2008-08-01

    Hydrodynamic simulations have been carried out using the multi-physics radiation hydrodynamics code HYDRA and the simplified one-dimensional hydrodynamics code DISH. We simulate possible targets for a near-term experiment at LBNL (the Neutralized Drift Compression Experiment, NDCX) and possible later experiments on a proposed facility (NDCX-II) for studies of warm dense matter and inertial fusion energy related beam-target coupling. Simulations of various target materials (including solids and foams) are presented. Experimental configurations include single pulse planar metallic solid and foam foils. Concepts for double-pulsed and ramped-energy pulses on cryogenic targets and foams have been simulated for exploring direct drive beam target coupling, and concepts and simulations for collapsing cylindrical and spherical bubbles to enhance temperature and pressure for warm dense matter studies are described.

  12. Ion Beam Heated Target Simulations for Warm Dense Matter Physics and Inertial Fusion Energy

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, J J; Armijo, J; Bailey, D S; Friedman, A; Bieniosek, F M; Henestroza, E; Kaganovich, I; Leung, P T; Logan, B G; Marinak, M M; More, R M; Ng, S F; Penn, G E; Perkins, L J; Veitzer, S; Wurtele, J S; Yu, S S; Zylstra, A B

    2008-08-12

    Hydrodynamic simulations have been carried out using the multi-physics radiation hydrodynamics code HYDRA and the simplified one-dimensional hydrodynamics code DISH. We simulate possible targets for a near-term experiment at LBNL (the Neutralized Drift Compression Experiment, NDCX) and possible later experiments on a proposed facility (NDCX-II) for studies of warm dense matter and inertial fusion energy related beam-target coupling. Simulations of various target materials (including solids and foams) are presented. Experimental configurations include single pulse planar metallic solid and foam foils. Concepts for double-pulsed and ramped-energy pulses on cryogenic targets and foams have been simulated for exploring direct drive beam target coupling, and concepts and simulations for collapsing cylindrical and spherical bubbles to enhance temperature and pressure for warm dense matter studies are described.

  13. Extreme ultraviolet diagnosis of a neutral-beam-heated mirror machine

    International Nuclear Information System (INIS)

    Extreme ultraviolet emissions from the LLL 2XIIB fusion research experiment have been studied. (2XIIB was a magnetic-mirror-plasma-confinement device; beams of high-energy (20 keV) neutral deuterium created a high-density, high-temperature plasma.) A normal-incidence concave-grating monochromator, equipped with a windowless photomultiplier tube, was used to measure emissions in the spectral region from 400 Angstrom to 1600 A. Emissions of oxygen, titanium, carbon, nitrogen, and deuterium were identified; the oxygen brightnesses at times exceeded 1018 ph-s-1-cm-2-sr-1. A survey of the emission characteristics found the oxygen concentration was 3%, the other impurities had concentrations near 0.4%. The radiated power loss was about 5% of the deposited neutral beam power

  14. 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...

  15. Linearizing Intra-Train Beam-Beam Deflection Feedback

    International Nuclear Information System (INIS)

    Beam-beam deflection feedback acting within the crossing time of a single bunch train may be needed to keep linear collider beams colliding at high luminosity. In a short-pulse machine such as the Next Linear Collider (NLC) this feedback must converge quickly to be useful. The non-linear nature of beam-beam deflection vs. beam-beam offset in these machines precludes obtaining both rapid convergence and a stable steady-state lock to beam offsets with a linear feedback algorithm. We show that a simply realizable programmable non-linear amplifier in the feedback loop can linearize the feedback loop, approximately compensating the beam-beam deflection non-linearity. Performance of a prototype non-linear amplifier is shown. Improvement of convergence and stability of the beam-beam feedback loop is simulated

  16. Beaming teaching application

    DEFF Research Database (Denmark)

    Markovic, Milos; Madsen, Esben; Olesen, Søren Krarup;

    2012-01-01

    BEAMING is a telepresence research project aiming at providing a multimodal interaction between two or more participants located at distant locations. One of the BEAMING applications allows a distant teacher to give a xylophone playing lecture to the students. Therefore, rendering of the xylophon...

  17. Ionization beam scanner

    CERN Multimedia

    CERN PhotoLab

    1973-01-01

    Inner structure of an ionization beam scanner, a rather intricate piece of apparatus which permits one to measure the density distribution of the proton beam passing through it. On the outside of the tank wall there is the coil for the longitudinal magnetic field, on the inside, one can see the arrangement of electrodes creating a highly homogeneous transverse electric field.

  18. Beam Stop For High-Power Lasers

    Science.gov (United States)

    Mcdermid, Iain S.; Williamson, William B.

    1990-01-01

    Graphite/aluminum plate absorbs most of light. Beam stop fits on standard optical mounting fixture. Graphite plate thick enough to absorb incident laser beam but thin enough to transfer heat quickly to heat sink. Device used for variety of blocking purposes. For example, blocks laser beam after it passes through experimental setup, or at each stage of setup so stages checked and tested in sequence. Negligible reflectance of device is valuable safety feature, protecting both users and equipment from reflections.

  19. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    The use of glass as a load carrying material in structural elements is rarely seen even though glass is a popular material for many architects. This is owed to the unreliable and low tensile strength, which is due to surface flaws and high brittleness of the material. These properties lead...... to breakage without any warning or ductility, which can be catastrophic if no precautions are taken. One aspect of this issue is treated here by looking at the possibility of mechanically reinforcing glass beams in order to obtain ductile failure for such a structural component. A mechanically reinforced...... laminated float glass beam is constructed and tested in four-point bending. The beam consist of 4 layers of glass laminated together with a slack steel band glued onto the bottom face of the beam. The glass parts of the tested beams are \\SI{1700}{mm} long and \\SI{100}{mm} high, and the total width of one...

  20. Beam director design report

    Energy Technology Data Exchange (ETDEWEB)

    Younger, F.C.

    1986-08-01

    A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 30/sup 0/ beam-bending achromat and prototype vernier steering magnet were designed and built. In volume II, copies are included of the funding instruments, requests for quotations, purchase orders, a complete set of as-built drawings, magnetic measurement reports, the concept design report, and the final report on the design and fabrication project. (LEW)

  1. Beam director design report

    International Nuclear Information System (INIS)

    A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 300 beam-bending achromat and prototype vernier steering magnet were designed and built. In volume II, copies are included of the funding instruments, requests for quotations, purchase orders, a complete set of as-built drawings, magnetic measurement reports, the concept design report, and the final report on the design and fabrication project

  2. In Situ Mitigation of Subsurface and Peripheral Focused Ion Beam Damage via Simultaneous Pulsed Laser Heating.

    Science.gov (United States)

    Stanford, Michael G; Lewis, Brett B; Iberi, Vighter; Fowlkes, Jason D; Tan, Shida; Livengood, Rick; Rack, Philip D

    2016-04-01

    Focused helium and neon ion (He(+)/Ne(+)) beam processing has recently been used to push resolution limits of direct-write nanoscale synthesis. The ubiquitous insertion of focused He(+)/Ne(+) beams as the next-generation nanofabrication tool-of-choice is currently limited by deleterious subsurface and peripheral damage induced by the energetic ions in the underlying substrate. The in situ mitigation of subsurface damage induced by He(+)/Ne(+) ion exposures in silicon via a synchronized infrared pulsed laser-assisted process is demonstrated. The pulsed laser assist provides highly localized in situ photothermal energy which reduces the implantation and defect concentration by greater than 90%. The laser-assisted exposure process is also shown to reduce peripheral defects in He(+) patterned graphene, which makes this process an attractive candidate for direct-write patterning of 2D materials. These results offer a necessary solution for the applicability of high-resolution direct-write nanoscale material processing via focused ion beams.

  3. Muon Beam at the Fermilab Test Beam Area

    OpenAIRE

    Denisov, Dmitri; Evdokimov, Valery; Lukić, Strahinja; Ujić, Predrag

    2016-01-01

    The intensities and profiles of the muon beam behind the beam dump of the Fermilab test beam area when the facility is running in the "pion" beam mode are measured and summarized in this note. This muon beam with momenta in the range 10 - 50 GeV/c provides an opportunity to perform various measurements in parallel with other users of the test beam area.

  4. Beam Interlocks for LHC and SPS

    CERN Document Server

    Dinius, A; Gimeno-Vicente, J; Nouchi, P; Puccio, B; Schmidt, R; Wenninger, J

    2003-01-01

    The Large Hadron Collider at CERN (LHC) will operate at 7 TeV/c with a luminosity of 10 cms. This requires two beams with about 3^10 protons/beam, corresponding to a stored energy of about 350 MJ, sufficient to heat and melt 500 kg of copper. Protection of equipment from damage in case of uncontrolled beam losses is challenging. Injection of the beam from the SPS to the LHC could already damage equipment and is only permitted when all LHC systems are correctly prepared. In case of an uncontrolled loss of the circulating LHC beams, it is required to extract the beams into a specially designed target as soon as possible. Beam loss monitors and equipment for hardware surveillance are distributed around the 26 km long accelerator. In case of failures or beam losses, the beam interlock system is informed and sends a dump request to the beam dumping system. The beam interlock system also inhibits injection when the LHC is not ready for beam. In this paper the requirements for the beam interlock system are discussed...

  5. Diffraction of a Laser Beam.

    Science.gov (United States)

    Jodoin, Ronald E.

    1979-01-01

    Investigates the effect of the nonuniform irradiance across a laser beam on diffraction of the beam, specifically the Fraunhofer diffraction of a laser beam with a Gaussian irradiance profile as it passes through a circular aperture. (GA)

  6. Electron Beam Lithography

    Science.gov (United States)

    Harriott, Lloyd R.

    1997-04-01

    Electron beams have played a significant role in semiconductor technology for more than twenty years. Early electron beam machines used a raster scanned beam spot to write patterns in electron-sensitive polymer resist materials. The main application of electron beam lithography has been in mask making. Despite the inherently high spatial resolution and wide process margins of electron beam lithography, the writing rate for semiconductor wafers has been too slow to be economically viable on a large scale. In the late 1970's, variable shape electron beam writing was developed, projecting a rectangular beam whose size can be varied for each "shot" exposure of a particular pattern, allowing some integrated circuits to be made economically where a variety of "customized" patterns are desired. In the cell or block projection electron beam exposure technique, a unit cell of a repetitive pattern is projected repeatedly to increase the level of parallelism. This can work well for highly repetitive patterns such as memory chips but is not well suited to complex varying patterns such as microprocessors. The rapid progress in the performance of integrated circuits has been largely driven by progress in optical lithography, through improvements in lens design and fabrication as well as the use of shorter wavelengths for the exposure radiation. Due to limitations from the opacity of lens and mask materials, it is unlikely that conventional optical printing methods can be used at wavelengths below 193 nm or feature sizes much below 180 nm. One candidate technology for a post-optical era is the Scattering with Angular Limitation Projection Electron-beam Lithography (SCALPEL) approach, which combines the high resolution and wide process latitude inherent in electron beam lithography with the throughput of a parallel projection system. A mask consisting of a low atomic number membrane and a high atomic number pattern layer is uniformly illuminated with high energy (100 ke

  7. Beam Imaging and Luminosity Calibration

    CERN Document Server

    Klute, Markus; Salfeld-Nebgen, Jakob

    2016-01-01

    We discuss a method to reconstruct two-dimensional proton bunch densities using vertex distributions accumulated during LHC beam-beam scans. The $x$-$y$ correlations in the beam shapes are studied and an alternative luminosity calibration technique is introduced. We demonstrate the method on simulated beam-beam scans and estimate the uncertainty on the luminosity calibration associated to the beam-shape reconstruction to be below 1\\%.

  8. Charge exchange recombination spectroscopy measurements in the extreme ultraviolet region of central carbon concentrations during high power neutral beam heating in TFTR [Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    The carbon concentration in the central region of TFTR discharges with high power neutral beam heating has been measured by charge-extracted recombination spectroscopy (CXRS) of the C+5 n = 3--4 transition in the extreme ultraviolet region. The carbon concentrations were deduced from absolute measurements of the line brightness using a calculation of the beam attenuation and the appropriate cascade-corrected line excitation rates. As a result of the high ion temperatures in most of the discharges, the contribution of beam halo neutrals to the line brightness was significant and therefore had to be included in the modeling of the data. Carbon concentrations have been measured in discharges with Ip = 1.0-1.6 MA and beam power in the range of 2.6-30 MW, including a number of supershots. The results are in good agreement with carbon concentrations deduced from the visible bremsstrahlung Zeff and metallic impurity concentrations measured by x-ray pulse-height analysis, demonstrating the reliability of the atomic rates used in the beam attenuation and line excitation calculations. Carbon is the dominant impurity species in these discharges; the oxygen concentration measured via CXRS in a high beam power case was 0.0006 of ne, compard to 0.04 for carbon. Trends with Ip and beam power in the carbon concentration and the inferred deuteron concentration are presented. The carbon concentration is independent of Ip and decreases from 0.13 at 2.6 MW beam power to 0.04 at 30 MW, while the deuteron concentration increases from 0.25 to 0.75 over the same range of beam power. These changes are primarily the result of beam particle fueling, as the carbon density did not vary significantly with beam power. The time evolutions of the carbon and deuteron concentrations during two high power beam pulses, one which exhibited a carbon bloom and one which did not, are compared. 30 refs., 12 figs., 2 tabs

  9. Numerical Simulation of Subcooled Boiling Inside High-Heat-Flux Component with Swirl Tube in Neutral Beam Injection System

    International Nuclear Information System (INIS)

    In order to realize steady-state operation of the neutral beam injection (NBI) system with high beam energy, an accurate thermal analysis and a prediction about working conditions of heat-removal structures inside high-heat-flux (HHF) components in the system are key issues. In this paper, taking the HHF ion dump with swirl tubes in NBI system as an example, an accurate thermal dynamic simulation method based on computational fluid dynamics (CFD) and the finite volume method is presented to predict performance of the HHF component. In this simulation method, the Eulerian multiphase method together with some empirical corrections about the inter-phase transfer model and the wall heat flux partitioning model are considered to describe the subcooled boiling. The reliability of the proposed method is validated by an experimental example with subcooled boiling inside swirl tube. The proposed method provides an important tool for the refined thermal and flow dynamic analysis of HHF components, and can be extended to study the thermal design of other complex HHF engineering structures in a straightforward way. The simulation results also verify that the swirl tube is a promising heat removing structure for the HHF components of the NBI system. (fusion engineering)

  10. Effect of melt surface depression on the vaporization rate of a metal heated by an electron beam

    International Nuclear Information System (INIS)

    In order to produce high density vapor, a metal confined in a water cooled crucible is heated by an electron beam (eb). The energy transfer to the metal causes partial melting, forming a pool where the flow is driven by temperature induced buoyancy and capillary forces. Furthermore, when the vaporization rate is high, the free surface is depressed by the thrust of the vapor. The main objective of this paper is to analyse the combined effects of liquid flow and vapor condensation back on the liquid surface. This is done with TRIO-EF, a general purpose fluid mechanics finite element code. A suitable iterative scheme is used to calculate the free surface flow and the temperature field. The numerical simulation gives an insight about the influence of the free surface in heat transfer. The depression of the free surface induces strong effects on both liquid and vapor. As liquid is concerned, buoyancy convection in the pool is enhanced, the energy flux from electron beam is spread and constriction of heat flux under the eb spot is weakened. It results that heat transfer towards the crucible is reinforced. As vapor is concerned, its fraction that condenses back on the liquid surface is increased. These phenomena lead to a saturation of the net vaporization rate as the eb spot radius is reduced, at constant eb power. (author). 8 refs., 13 figs., 2 tabs

  11. Electron beam silicon purification

    Energy Technology Data Exchange (ETDEWEB)

    Kravtsov, Anatoly [SIA ' ' KEPP EU' ' , Riga (Latvia); Kravtsov, Alexey [' ' KEPP-service' ' Ltd., Moscow (Russian Federation)

    2014-11-15

    Purification of heavily doped electronic grade silicon by evaporation of N-type impurities with electron beam heating was investigated in process with a batch weight up to 50 kilos. Effective temperature of the melt, an indicative parameter suitable for purification process characterization was calculated and appeared to be stable for different load weight processes. Purified material was successfully approbated in standard CZ processes of three different companies. Each company used its standard process and obtained CZ monocrystals applicable for photovoltaic application. These facts enable process to be successfully scaled up to commercial volumes (150-300 kg) and yield solar grade silicon. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Simulations of beam-beam and beam-wire interactions in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung J.; Sen, Tanaji; /Fermilab; Abreu, Natalia P.; Fischer, Wolfram; /Brookhaven

    2009-02-01

    The beam-beam interaction is one of the dominant sources of emittance growth and luminosity lifetime deterioration. A current carrying wire has been proposed to compensate long-range beam-beam effects in the LHC and strong localized long-range beam-beam effects are experimentally investigated in the RHIC collider. Tune shift, beam transfer function, and beam loss rate are measured in dedicated experiments. In this paper, they report on simulations to study the effect of beam-wire interactions based on diffusive apertures, beam loss rates, and beam transfer function using a parallelized weak-strong beam simulation code (BBSIMC). The simulation results are compared with measurements performed in RHIC during 2007 and 2008.

  13. Polarized atomic hydrogen beam

    Energy Technology Data Exchange (ETDEWEB)

    Chan, N.; Crowe, D.M.; Lubell, M.S.; Tang, F.C.; Vasilakis, A.; Mulligan, F.J.; Slevin, J.

    1988-12-01

    We describe the design and operating characteristics of a simple polarized atomic hydrogen beam particularly suitable for applications to crossed beams experiments. In addition to experimental measurements, we present the results of detailed computer models, using Monte-Carlo ray tracing techniques, optical analogs, and phase-space methods, that not only provide us with a confirmation of our measurement, but also allow us to characterize the density, polarization, and atomic fraction of the beam at all points along its path. As a subsidiary result, we also present measurements of the relative and absolute efficiencies of the V/G Supavac mass analyzer for masses 1 and 2.

  14. Laser beam quality metrics

    CERN Document Server

    Ross, T Sean

    2013-01-01

    This book is geared toward engineers and laser physicists involved in the development of laser-based systems, especially laser systems for directed energy applications. It begins with a review of basic laser properties and moves to definitions and implications of the various standard beam quality metrics such as [i]M[/i][sup]2[/sup], power in the bucket, brightness, beam parameter product, and Strehl ratio. The practical aspects of beam metrology, which have not been sufficiently addressed in the literature, are amply covered here.

  15. Beam instrumentation performance overview

    CERN Document Server

    Sapinski, M

    2012-01-01

    The 2011 run has proven that LHC can operate safely and stably with higher bunch intensity and smaller transverse emittance than foreseen in the Technical Design Report. In this presentation the performance of the Beam Position Monitoring (BPM) system is discussed. The improvements to the system, those made during the last year and those expected to be done for 2012 run are presented. The status of the three types of devices measuring the transverse beam emittance, wire scanners (BWS), synchrotron radiation monitors (BSRT) and beam gas ionization monitors (BGI), are shown. The control room applications are reviewed and a set of improvements proposed by the operation team is presented.

  16. Electron Beam for LHC

    CERN Document Server

    Krasny, M W

    2005-01-01

    A method of delivering a monochromatic electron beam to the LHC interaction points is proposed. In this method, heavy ions are used as carriers of the projectile electrons. Acceleration, storage and collision-stability aspects of such a hybrid beam is discussed and a new beam-cooling method is presented. This discussion is followed by a proposal of the Parasitic Ion-Electron collider at LHC (PIE@LHC). The PIE@LHC provides an opportunity, for the present LHC detectors, to enlarge the scope of their research program by including the program of electron-proton and electron-nucleuscollisions with minor machine and detector investments.

  17. Use of beam deflection to control an electron beam wire deposition process

    Science.gov (United States)

    Taminger, Karen M. (Inventor); Hofmeister, William H. (Inventor); Hafley, Robert A. (Inventor)

    2013-01-01

    A method for controlling an electron beam process wherein a wire is melted and deposited on a substrate as a molten pool comprises generating the electron beam with a complex raster pattern, and directing the beam onto an outer surface of the wire to thereby control a location of the wire with respect to the molten pool. Directing the beam selectively heats the outer surface of the wire and maintains the position of the wire with respect to the molten pool. An apparatus for controlling an electron beam process includes a beam gun adapted for generating the electron beam, and a controller adapted for providing the electron beam with a complex raster pattern and for directing the electron beam onto an outer surface of the wire to control a location of the wire with respect to the molten pool.

  18. 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.

  19. LEDA BEAM DIAGNOSTICS INSTRUMENTATION: BEAM POSITION MONITORS

    International Nuclear Information System (INIS)

    The Low Energy Demonstration Accelerator (LEDA) facility located at Los Alamos National Laboratory (LANL) accelerates protons to an energy of 6.7-MeV and current of 100-mA operating in either a pulsed or cw mode. Of key importance to the commissioning and operations effort is the Beam Position Monitor system (BPM). The LEDA BPM system uses five micro-stripline beam position monitors processed by log ratio processing electronics with data acquisition via a series of custom TMS32OC40 Digital Signal Processing (DSP) boards. Of special interest to this paper is the operation of the system, the log ratio processing, and the system calibration technique. This paper will also cover the DSP system operations and their interaction with the main accelerator control system

  20. Control on Electron Beam Scanning Track

    Institute of Scientific and Technical Information of China (English)

    王学东; 姚舜

    2004-01-01

    In order to use electron beam as a movable welding heat source and whose energy distribution along its moving trace can be controlled, a method of electron beam scanning track and scanning mode control was put forward. Based on it, the electron beam scanning track and scanning mode can be edited at will according to actual requirements, and the energy input of each point of the scanning track can be controlled. In addition, the scanning frequency and points control, real time adjusting of the scanning track etc. were explained. This method can be used in electron beam brazing, surface modification, surface heat treatment etc.

  1. Beam Coupling Impedance of the New Beam Screen of the LHC Injection Kicker Magnets

    CERN Document Server

    Day, H; Caspers, F; Métral, E; Salvant, B; Uythoven, J

    2014-01-01

    The LHC injection kicker magnets experienced significant beam induced heating of the ferrite yoke, with high beam currents circulating for many hours, during operation of the LHC in 2011 and 2012. The causes of this beam induced heating were studied in depth and an improved beam screen implemented to reduce the impedance. Results of measurements and simulations of the new beam screen design are presented in this paper: these are used to predict power loss for operation after long shutdown 1 and for proposed HL-LHC operational parameters.

  2. Optimization of a slab heating pattern for minimum energy consumption in a walking-beam type reheating furnace

    International Nuclear Information System (INIS)

    A two-dimensional mathematical heat transfer model for the prediction of the temperature history of steel slabs was performed in order to obtain the optimal heating pattern of these slabs with minimum energy consumption in a walking-beam type reheating furnace. An algorithm developed with a simplified conjugated-gradient method combined with a shooting method, was used as an optimizer to design the furnace temperature distribution, including the preheating zone, heating zone and soaking zone temperatures. Comparison with the in-situ experimental data indicated that the present heat transfer model works well for the prediction of the thermal behavior of a slab in the reheating furnace. The effect of the furnace temperature distribution on the design requirements, such as energy required for heating a slab, slab temperature uniformity at the furnace exit and slab discharging temperature, were investigated. The parametric study results indicated that energy consumption significantly decreases with reductions in the preheating zone temperature. The optimal design also resulted in lower energy consumption for heating a slab as compared to the original operational conditions in the steel plant. - Highlights: • The heating process of steel slabs in a reheating furnace is numerically simulated. • An algorithm is developed to search for the optimal heating pattern of a slab. • Energy consumption decreases with reductions in the preheating zone temperature

  3. Bunched beam stochastic cooling

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Jie

    1992-09-01

    The scaling laws for bunched-beam stochastic cooling has been derived in terms of the optimum cooling rate and the mixing condition. In the case that particles occupy the entire sinusoidal rf bucket, the optimum cooling rate of the bunched beam is shown to be similar to that predicted from the coasting-beam theory using a beam of the same average density and mixing factor. However, in the case that particles occupy only the center of the bucket, the optimum rate decrease in proportion to the ratio of the bunch area to the bucket area. The cooling efficiency can be significantly improved if the synchrotron side-band spectrum is effectively broadened, e.g. by the transverse tune spread or by using a double rf system.

  4. Bunched beam stochastic cooling

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Jie.

    1992-01-01

    The scaling laws for bunched-beam stochastic cooling has been derived in terms of the optimum cooling rate and the mixing condition. In the case that particles occupy the entire sinusoidal rf bucket, the optimum cooling rate of the bunched beam is shown to be similar to that predicted from the coasting-beam theory using a beam of the same average density and mixing factor. However, in the case that particles occupy only the center of the bucket, the optimum rate decrease in proportion to the ratio of the bunch area to the bucket area. The cooling efficiency can be significantly improved if the synchrotron side-band spectrum is effectively broadened, e.g. by the transverse tune spread or by using a double rf system.

  5. Neutrino beams and experiments

    International Nuclear Information System (INIS)

    After a brief review of the early history of neutrino experiments, the principle of neutrino beams at proton accelerators is described and a survey of neutrino experiments since 1963 is given. ((orig.))

  6. HIRENASD Beam FEM

    Data.gov (United States)

    National Aeronautics and Space Administration — This contains attempts to create BEAM FEM model. I have started a Blog to discuss this... please put your comments there and I will attempt to keep everything...

  7. Pulsed electron beam precharger

    Energy Technology Data Exchange (ETDEWEB)

    Finney, W.C. (ed.); Shelton, W.N.

    1989-01-01

    This is the fifth in a series of contracts and grants exploring the advanced particulate pollution control technology of electron beam precipitation. The chief goal of the current contract is to develop a laboratory scale electron beam precharger using a pulsed electric field to the proof-of-concept stage. Contract tasks leading to the achievement of this goal are generally divided up into two categories: tasks required to bring the Electron Beam Precipitator (EBP) test system up to an operational level for the contract work, and tasks concerning the actual experimental and analytical phase of the study. Not unexpectedly, the early portion of the contract duration will be devoted to the commissioning of the EBP and its many subsystems, while the latter portion will devote itself to testing the new pulsed electron beam precharger.

  8. Longitudinal beam dynamics

    CERN Document Server

    Tecker, F

    2014-01-01

    The course gives a summary of longitudinal beam dynamics for both linear and circular accelerators. After discussing different types of acceleration methods and synchronism conditions, it focuses on the particle motion in synchrotrons.

  9. LHCb: Beam Pipe portrait

    CERN Multimedia

    LHCb, Collaboration

    2005-01-01

    The proton beams circulate in the accelerator in Ultra High Vacuum to make them interact only with each other when colliding at the interaction point. A special beam pipe "holds" the vacuum where they pass through the LHCb detector: it has to be mechanically very strong to stand the difference in pressure between the vacuum inside it and the air in the cavern but also be as transparent as possible for the particles originating in the proton−proton collisions.

  10. LHCb: Beam Pipe

    CERN Multimedia

    LHCb, Collaboration

    2005-01-01

    The proton beams circulate in the accelerator in Ultra High Vacuum to make them interact only with each other when colliding at the interaction point. A special beam pipe "holds" the vacuum where they pass through the LHCb detector:it has to be mechanically very strong to stand the difference in pressure between the vacuum inside it and the air in the cavern but also be as transparent as possible for the particles originating in the proton−proton collisions.

  11. Neutral beams for mirrors

    International Nuclear Information System (INIS)

    An important demonstration of negative ion technology is proposed for FY92 in the MFTF-α+T, an upgrade of the Mirror Fusion Test Facility at the Lawrence Livermore National Laboratory. This facility calls for 200-keV negative ions to form neutral beams that generate sloshing ions in the reactor end plugs. Three different beam lines are considered for this application. Their advantages and disadvantages are discussed

  12. Transverse Beam Size Effects in Beam Position Monitors

    Science.gov (United States)

    Kurennoy, Sergey

    2001-04-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The corrections to BPM signals due to a finite beam size are found analytically for a few particular transverse distributions of the beam current. The results for fields can also be directly applied for calculating the beam coupling impedances of small discontinuities.

  13. Beam-beam studies for the High-Energy LHC

    CERN Document Server

    Ohmi, K; Zimmermann, F

    2011-01-01

    LHC upgrades are being considered both towards higher luminosity (HL-LHC) and towards higher energy (HE-LHC). In this paper we report initial studies of the beam-beam effects in the HE-LHC [1]. The HE-LHC aims at beam energies of 16.5 TeV, where the transverse emittance decreases due to synchrotron radiation with a 2-hour damping time. As a result of this emittance, shrinkage the beam-beam parameter increases with time, during a physics store. The beam-beam limit in the HE-LHC is explored using computer simulations.

  14. Low intensity beam target unit

    CERN Multimedia

    1976-01-01

    This is a wheel fitted with many targets around its periphery (each with three longitudinally arranged thin rods) of which one is placed into the beam via a rotation of the wheel. Upstream of each target is placed a luminescent screen, aligbed on each target axis and viewed with a TV camera, to make sure that one is hitting the target. This target unit was probably used to study target's behaviour (like beam heating). Gualtiero Del Torre stands on the left, Pierre Gerdil on the right.

  15. Study of plasma heating by intense relativistic electron beams. Progress report, 31 January 1974--31 October 1974

    International Nuclear Information System (INIS)

    An experiment to investigate plasma heating resulting from the interaction of an intense rotating relativistic electron beam is described. Calculations show that a radial electric field is set up within the plasma by the Hall effect. The magnitude of this electric field is E/sub r/ = 300 (n/sub b//n/sub p/)B/sub z/ where n/sub b/ is the beam density, n/sub p/ the plasma density; E/sub r/(K - volts/cm) and B/sub z/(K-gauss) are the electric and magnetic fields. Ions for which the magnetic field can be neglected would be accelerated in the E/sub r/--field resulting in ion temperatures of the order of a kilovolt for the experiment. Theoretical investigations of the stability of the rotating beam plasma configuration show that it is unstable. However, the growth is proportional to one over the cube root of the conductivity and results in an axial modulation of the beam which should not be disruptive. Construction and testing of the plasma gun was completed. The plasma gun produces a plasma which fills the 20 cm diameter chamber. The density was measured with a 2 mm microwave interferometer and found to be greater than 1014 particles/cm3. The plasma velocity is of order 10 cm/μs. This results in a highly ionized plasma since the slow neutrals remain behind. It is also found that the plasma has sufficient velocity to go through the cusp and provide charge neutralization in the diode-cusp region. (U.S.)

  16. LSST optical beam simulator

    CERN Document Server

    Tyson, J A; Gilmore, K; Bradshaw, A; Claver, C; Klint, M; Muller, G; Poczulp, G; Resseguie, E

    2014-01-01

    We describe a camera beam simulator for the LSST which is capable of illuminating a 60mm field at f/1.2 with realistic astronomical scenes, enabling studies of CCD astrometric and photometric performance. The goal is to fully simulate LSST observing, in order to characterize charge transport and other features in the thick fully depleted CCDs and to probe low level systematics under realistic conditions. The automated system simulates the centrally obscured LSST beam and sky scenes, including the spectral shape of the night sky. The doubly telecentric design uses a nearly unit magnification design consisting of a spherical mirror, three BK7 lenses, and one beam-splitter window. To achieve the relatively large field the beam-splitter window is used twice. The motivation for this LSST beam test facility was driven by the need to fully characterize a new generation of thick fully-depleted CCDs, and assess their suitability for the broad range of science which is planned for LSST. Due to the fast beam illuminatio...

  17. WELD FORMATION CONTROL AT ELECTRON BEAM WELDING WITH BEAM OSCILLATIONS

    OpenAIRE

    Trushnikov, Dmitriy; Koleva, Elena; Mladenov, Georgy; Shcherbakov, A.

    2014-01-01

    Electron beam welding is used extensively to produce essential machine parts. The control of the basic beam parameters beam power or beam current at constant accelerating voltage, welding speed, current of focusing lens and distance between electron gun and welded sample surface is not enough to obtain at most of the regimes sound welds. Control of the focus position using analysis of the high frequency component of the current, collected by plasma, at periodic interactions on the beam (the o...

  18. Heat shrink ability of electron-beam-modified thermoplastic elastomeric films from blends of ethylene-vinylacetate copolymer and polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Chattopadhyay, S.; Chaki, T.K.; Bhowmick, Anil K. E-mail: anilkb@rtc.iitkgp.ernet.in

    2000-11-01

    The heat shrink ability of electron-beam-irradiated thermoplastic elastomeric films from blends of ethylene-vinylacetate copolymer (EVA) and low-density polyethylene (LDPE) has been investigated in this paper. The effects of temperature, time and extent of stretching and shrinkage temperature and time have been reported. Based on the above data, the optimized conditions in terms of high heat shrinkage and low amnesia rating have been evaluated. Influence of radiation doses (0-500 kGy), multifunctional sensitizer levels (ditri methylol propane tetraacrylate, DTMPTA), and blend proportions on heat shrink ability has been explained with the help of gel fraction and X-ray data. With the increase in radiation dose, gel fraction increases, which in turn gives rise to low values of heat shrinkage and amnesia rating. At a constant radiation dose and blend ratio, percent heat shrinkage is found to decrease with increase in DTMPTA level. Gel content increases with the increase in EVA content of the blend at a constant radiation dose and monomer level, giving rise to decrease in heat shrink ability. Heat shrinkage increases with the increase in percent crystallinity, although the amnesia rating follows the reverse trend.

  19. Beam loss reduction by magnetic shielding using beam pipes and bellows of soft magnetic materials

    Science.gov (United States)

    Kamiya, J.; Ogiwara, N.; Hotchi, H.; Hayashi, N.; Kinsho, M.

    2014-11-01

    One of the main sources of beam loss in high power accelerators is unwanted stray magnetic fields from magnets near the beam line, which can distort the beam orbit. The most effective way to shield such magnetic fields is to perfectly surround the beam region without any gaps with a soft magnetic high permeability material. This leads to the manufacture of vacuum chambers (beam pipes and bellows) with soft magnetic materials. A Ni-Fe alloy (permalloy) was selected for the material of the pipe parts and outer bellows parts, while a ferritic stainless steel was selected for the flanges. An austenitic stainless steel, which is non-magnetic material, was used for the inner bellows for vacuum tightness. To achieve good magnetic shielding and vacuum performances, a heat treatment under high vacuum was applied during the manufacturing process of the vacuum chambers. Using this heat treatment, the ratio of the integrated magnetic flux density along the beam orbit between the inside and outside of the beam pipe and bellows became small enough to suppress beam orbit distortion. The outgassing rate of the materials with this heat treatment was reduced by one order magnitude compared to that without heat treatment. By installing the beam pipes and bellows of soft magnetic materials as part of the Japan Proton Accelerator Research Complex 3 GeV rapid cycling synchrotron beam line, the closed orbit distortion (COD) was reduced by more than 80%. In addition, a 95.5% beam survival ratio was achieved by this COD improvement.

  20. Dual-Cantilever-Beam Accelerometer

    Science.gov (United States)

    Reynolds, Emmitt A.; Speckhart, Frank H.

    1988-01-01

    Sensitivity to velocity changes along beam axis reduced. Weighted-end cantilever beams of accelerometer deflected equally by acceleration in y direction. When acceleration to right as well as up or down, right beam deflected more, while left beam deflected less. Bridge circuit averages outputs of strain gauges measuring deflections, so cross-axis sensitivity of accelerometer reduced. New device simple and inexpensive.

  1. Multi-Beam Optical Tweezers

    DEFF Research Database (Denmark)

    2003-01-01

    A set of multi-beam electromagnetic tweezers is provided comprising a multi-beam generator for emission of a plurality of electromagnetic beams, at least some of the electromagnetic beams intersecting each other, or, having an individually controlled polarization whereby the position and/or angul...

  2. Holographic memory using beam steering

    Science.gov (United States)

    Chao, Tien-Hsin (Inventor); Hanan, Jay C. (Inventor); Reyes, George F. (Inventor); Zhou, Hanying (Inventor)

    2007-01-01

    A method, apparatus, and system provide the ability for storing holograms at high speed. A single laser diode emits a collimated laser beam to both write to and read from a photorefractice crystal. One or more liquid crystal beam steering spatial light modulators (BSSLMs) steer a reference beam, split from the collimated laser beam, at high speed to the photorefractive crystal.

  3. 3D terahertz beam profiling

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Strikwerda, Andrew; Wang, Tianwu;

    2013-01-01

    We present a characterization of THz beams generated in both a two-color air plasma and in a LiNbO3 crystal. Using a commercial THz camera, we record intensity images as a function of distance through the beam waist, from which we extract 2D beam profiles and visualize our measurements into 3D beam...

  4. Beam Trail Tracking at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Nicklaus, Dennis J. [Fermilab; Carmichael, Linden Ralph [Fermilab; Neswold, Richard [Fermilab; Yuan, Zongwei [Fermilab

    2015-01-01

    We present a system for acquiring and sorting data from select devices depending on the destination of each particular beam pulse in the Fermilab accelerator chain. The 15 Hz beam that begins in the Fermilab ion source can be directed to a variety of additional accelerators, beam lines, beam dumps, and experiments. We have implemented a data acquisition system that senses the destination of each pulse and reads the appropriate beam intensity devices so that profiles of the beam can be stored and analysed for each type of beam trail. We envision utilizing this data long term to identify trends in the performance of the accelerators

  5. Active beam spectroscopy for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Von Hellermann, M.; Giroud, C.; Jaspers, R. [Association Euratom-Fom, FOM Institute for Plasma Physics Rijnhuizen, Trilateral Euregio Cluster (Netherlands); Hawkes, N.C.; Mullane, M.O.; Zastrow, K.D. [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon (United Kingdom); Krasilnikov, A.; Tugarinov, S. [SRC RF TRINITI, Troitsk, Moscow region (Russian Federation); Lotte, P. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; McKee, G. [Wisconsin Univ., Madison, WI (United States); Malaquias, A. [Associacao EURATOM/IST, Instituto Superior Tecnico, Lisboa (Portugal); Rachlew, E. [Kungliga Tekniska Hoegskolan (KTH), Stockholm(Sweden)

    2003-07-01

    The latest status of 'Active Beam' related spectroscopy aspects as part of the ITER diagnostic scenario is presented. A key issue of the proposed scheme is based on the concept that in order to achieve the ultimate goal of global data consistency, all particles involved, that is, intrinsic and seeded impurity ions as well as helium ash ions and bulk plasma ions and also the plasma background data (e.g. magnetic and electric fields, electron density and temperature profiles) need to be addressed. A further sensible step in this direction is the decision of exploiting both a dedicated low-energy, low-power diagnostic beam (DNB, 2.2 MW 100 keV/amu) as well as the high-power, high-energy heating beams (HNB, 17 MW 500 keV/amu) for maximum diagnostic information. The authors report some new aspects referring to the use of DNB for motional Stark effect (MSE) where the main idea is to treat both beams (HNB and DNB) as potential diagnostic tools with complementary roles. The equatorial ports for the DNB promise excellent spatial resolution, however, the angles are less favourable for a polarimetric MSE exploitation. HNB can be used as probe beam for diagnosing slowing-down fusion alpha with a birth energy of 3,5 MeV.

  6. Effects of solution heat treatment on the microstructure and hardness of Inconel 740 superalloy prepared by electron beam smelting

    International Nuclear Information System (INIS)

    Highlights: • Electron beam smelting, a new method, was used to prepare the Inconel 740 superalloy. • The effect of solution heat treatment on electron beam smelting 740 was investigated. • TiNiSi phase’s content changes exponentially with solution temperature increasing. • γ′ precipitates coarsening occurs at 1150 °C, higher temperature cause their solution. • γ″ phase transformed into Nb0.03Ni3Ti0.97 phase at 1210 °C. - Abstract: Electron beam smelting (EBS) was used to prepare the Inconel 740 superalloy. The microstructure and hardness of Inconel 740 were investigated both under hot working condition and followed by solution heat treatment under high temperature ranging from 1120 to 1210 °C for 30 min. The results show that fine γ′ nucleus and primary MC carbides exist in the hot working superalloy. With increasing temperature of solution treatment, TiNiSi phase is gradually solutionized into the matrix, whose volume fraction decreases exponentially. γ′ precipitates coarsening occurs at 1150 °C, while higher temperature solution treatment leads to the solution of γ′ precipitates. γ″ phase has been found keeping a stringent coherent relationship with Nb0.03Ni3Ti0.97 phase at 1180 °C, and utterly transformed into Nb0.03Ni3Ti0.97 phase at 1210 °C. The hardness of the solution-treated superalloy is lower than that of hot working, the value decreases at first and then increases with increasing of solution temperature, which is attributed to dislocations interaction and localized shear stress caused by γ′ precipitates and local stress fields

  7. Effects of solution heat treatment on the microstructure and hardness of Inconel 740 superalloy prepared by electron beam smelting

    Energy Technology Data Exchange (ETDEWEB)

    You, Xiaogang [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province, Dalian 116023 (China); Tan, Yi, E-mail: tanyi@dlut.edu.cn [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province, Dalian 116023 (China); Li, Jiayan; Li, Pengting [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province, Dalian 116023 (China); Dong, Chuang [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian 116023 (China); Shi, Shuang; Liao, Jiao; Qin, Shiqiang [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province, Dalian 116023 (China)

    2015-07-25

    Highlights: • Electron beam smelting, a new method, was used to prepare the Inconel 740 superalloy. • The effect of solution heat treatment on electron beam smelting 740 was investigated. • TiNiSi phase’s content changes exponentially with solution temperature increasing. • γ′ precipitates coarsening occurs at 1150 °C, higher temperature cause their solution. • γ″ phase transformed into Nb{sub 0.03}Ni{sub 3}Ti{sub 0.97} phase at 1210 °C. - Abstract: Electron beam smelting (EBS) was used to prepare the Inconel 740 superalloy. The microstructure and hardness of Inconel 740 were investigated both under hot working condition and followed by solution heat treatment under high temperature ranging from 1120 to 1210 °C for 30 min. The results show that fine γ′ nucleus and primary MC carbides exist in the hot working superalloy. With increasing temperature of solution treatment, TiNiSi phase is gradually solutionized into the matrix, whose volume fraction decreases exponentially. γ′ precipitates coarsening occurs at 1150 °C, while higher temperature solution treatment leads to the solution of γ′ precipitates. γ″ phase has been found keeping a stringent coherent relationship with Nb{sub 0.03}Ni{sub 3}Ti{sub 0.97} phase at 1180 °C, and utterly transformed into Nb{sub 0.03}Ni{sub 3}Ti{sub 0.97} phase at 1210 °C. The hardness of the solution-treated superalloy is lower than that of hot working, the value decreases at first and then increases with increasing of solution temperature, which is attributed to dislocations interaction and localized shear stress caused by γ′ precipitates and local stress fields.

  8. Isochoric heating of DT fuels through PW-laser-produced proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Maynard, G. [Laboratoire de Physique des Gaz et des Pasmas, CNRS UMR8578, bat. 210, Universite Paris XI, F-91405, Orsay (France)]. E-mail: gilles.maynard@pgp.u-psud.fr; Barriga-Carrasco, M.D. [Laboratoire de Physique des Gaz et des Pasmas, CNRS UMR8578, bat. 210, Universite Paris XI, F-91405, Orsay (France)

    2005-05-21

    Laser Proton Source (LPS) can generate short bunch of energetic protons with a nearly zero initial emittance. It is thus expected that LPS can deposit a very high density of energy inside dense matter, in particular, in the context of fast ignition of an inertial fusion target. We investigate here one of the factors that can limit the density of deposited energy. It concerns the transverse diffusion, occurring during the transport between the LPS and DT. As the rear surface of LPS should be efficiently protected, the proton along its path has to interact with a substantial amount of high-Z material. Therefore the induced transverse dispersion can become significant. The transport of the proton beam inside a plasma target is calculated using a numerical code, which main features are presented.

  9. Solar Hard X-ray Source Sizes in a Beam-Heated and Ionised Chromosphere

    CERN Document Server

    O'Flannagain, A; Gallagher, P T

    2014-01-01

    Solar flare hard X-rays (HXRs) are produced as bremsstrahlung when an accelerated population of electrons interacts with the dense chromospheric plasma. HXR observations presented by using the Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) have shown that HXR source sizes are 3-6 times more extended in height than those predicted by the standard collisional thick target model (CTTM). Several possible explanations have been put forward including the multi-threaded nature of flare loops, pitch-angle scattering, and magnetic mirroring. However, the nonuniform ionisation (NUI) structure along the path of the electron beam has not been fully explored as a solution to this problem. Ionised plasma is known to be less effective at producing nonthermal bremsstrahlung HXRs when compared to neutral plasma. If the peak HXR emission was produced in a locally ionised region within the chromosphere, the intensity of emission will be preferentially reduced around this peak, resulting in a more extended source. Due to...

  10. Relationship between 578-nm (copper vapor) laser beam geometry and heat distribution within biological tissues

    Science.gov (United States)

    Ilyasov, Ildar K.; Prikhodko, Constantin V.; Nevorotin, Alexey J.

    1995-01-01

    Monte Carlo (MC) simulation model and the thermoindicative tissue phantom were applied for evaluation of a depth of tissue necrosis (DTN) as a result of quasi-cw copper vapor laser (578 nm) irradiation. It has been shown that incident light focusing angle is essential for DTN. In particular, there was a significant rise in DTN parallel to elevation of this angle up to +20 degree(s)C and +5 degree(s)C for both the MC simulation and tissue phantom models, respectively, with no further increase in the necrosis depth above these angles. It is to be noted that the relationship between focusing angles and DTN values was apparently stronger for the real target compared to the MC-derived hypothetical one. To what extent these date are applicable for medical practice can be evaluated in animal models which would simulate laser-assisted therapy for PWS or related dermatologic lesions with converged 578 nm laser beams.

  11. SOLAR HARD X-RAY SOURCE SIZES IN A BEAM-HEATED AND IONIZED CHROMOSPHERE

    International Nuclear Information System (INIS)

    Solar flare hard X-rays (HXRs) are produced as bremsstrahlung when an accelerated population of electrons interacts with the dense chromospheric plasma. HXR observations presented by Kontar et al. using the Ramaty High-Energy Solar Spectroscopic Imager have shown that HXR source sizes are three to six times more extended in height than those predicted by the standard collisional thick target model (CTTM). Several possible explanations have been put forward including the multi-threaded nature of flare loops, pitch-angle scattering, and magnetic mirroring. However, the nonuniform ionization (NUI) structure along the path of the electron beam has not been fully explored as a solution to this problem. Ionized plasma is known to be less effective at producing nonthermal bremsstrahlung HXRs when compared to neutral plasma. If the peak HXR emission was produced in a locally ionized region within the chromosphere, the intensity of emission will be preferentially reduced around this peak, resulting in a more extended source. Due to this effect, along with the associated density enhancement in the upper chromosphere, injection of a beam of electrons into a partially ionized plasma should result in an HXR source that is substantially more vertically extended relative to that for a neutral target. Here we present the results of a modification to the CTTM, which takes into account both a localized form of chromospheric NUI and an increased target density. We find 50 keV HXR source widths, with and without the inclusion of a locally ionized region, of ∼3 Mm and ∼0.7 Mm, respectively. This helps to provide a theoretical solution to the currently open question of overly extended HXR sources

  12. SOLAR HARD X-RAY SOURCE SIZES IN A BEAM-HEATED AND IONIZED CHROMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    O' Flannagain, Aidan M.; Gallagher, Peter T. [Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Brown, John C. [Astronomy and Astrophysics Group, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2015-02-01

    Solar flare hard X-rays (HXRs) are produced as bremsstrahlung when an accelerated population of electrons interacts with the dense chromospheric plasma. HXR observations presented by Kontar et al. using the Ramaty High-Energy Solar Spectroscopic Imager have shown that HXR source sizes are three to six times more extended in height than those predicted by the standard collisional thick target model (CTTM). Several possible explanations have been put forward including the multi-threaded nature of flare loops, pitch-angle scattering, and magnetic mirroring. However, the nonuniform ionization (NUI) structure along the path of the electron beam has not been fully explored as a solution to this problem. Ionized plasma is known to be less effective at producing nonthermal bremsstrahlung HXRs when compared to neutral plasma. If the peak HXR emission was produced in a locally ionized region within the chromosphere, the intensity of emission will be preferentially reduced around this peak, resulting in a more extended source. Due to this effect, along with the associated density enhancement in the upper chromosphere, injection of a beam of electrons into a partially ionized plasma should result in an HXR source that is substantially more vertically extended relative to that for a neutral target. Here we present the results of a modification to the CTTM, which takes into account both a localized form of chromospheric NUI and an increased target density. We find 50 keV HXR source widths, with and without the inclusion of a locally ionized region, of ∼3 Mm and ∼0.7 Mm, respectively. This helps to provide a theoretical solution to the currently open question of overly extended HXR sources.

  13. Review of nondiffracting Bessel beams

    Science.gov (United States)

    Lapointe, Michael R.

    1991-01-01

    The theory of nondiffracting beam propagation and experimental evidence for nearly-nondiffractive Bessel beam propagation are reviewed. The experimental results are reinterpreted using simple optics formulas, which show that the observed propagation distances are characteristic of the optical systems used to generate the beams and do not depend upon the initial beam profiles. A set of simple experiments are described which support this interpretation. It is concluded that nondiffracting Bessel beam propagation has not yet been experimentally demonstrated.

  14. Nonlinear combining of laser beams

    OpenAIRE

    Lushnikov, Pavel M.; Vladimirova, Natalia

    2014-01-01

    We propose to combine multiple laser beams into a single diffraction-limited beam by the beam self-focusing (collapse) in the Kerr medium. The beams with the total power above critical are first combined in the near field and then propagated in the optical fiber/waveguide with the Kerr nonlinearity. Random fluctuations during propagation eventually trigger strong self-focusing event and produce diffraction-limited beam carrying the critical power.

  15. A coupled analysis of fluid flow, heat transfer and deformation behavior of solidifying shell in continuously cast beam blank

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Eui; Yeo, Tae Jung; Oh, Kyu Hwan; Yoon, Jong Kyu [School of Materials Science and Engineering, Seoul Nat`l Univ., Seoul (Korea, Republic of); Han, Heung Nam [Oxford Center for Advanced Materials and Composites, Department of Materials, Univ. of Oxford (United Kingdom)

    1997-12-31

    A mathematical model for a coupled analysis of fluid flow, heat transfer and deformation behavior in the continuously cast beam blank has been developed. The fluid flow, heat transfer and solidification in the mold region were analyzed with 3-dimensional finite difference method (FDM) based on control volume method. A body fitted coordinate system was introduced for the complex geometry of the beam blank. The effects of turbulence and natural convection of molten steel were taken into account in determining the fluid flow in the strand. The thermo-elasto-plastic deformation behavior in the cast strand and the formation of air gap between the solidifying shell and the mold were analyzed by the finite element method (FEM) using the 2-dimensional slice temperature profile calculated by the FDM. The heat flow between the strand and the mold was evaluated by the coupled analysis between the fluid flow-heat transfer analysis and the thermo-elasto-plastic stress analysis. In order to determine the solid fraction in the mushy zone, the microsegregation of solute element was assessed. The effects of fluid flow on the heat transfer, the solidification of steel and the distribution of shell thickness during the casting of the beam blank were simulated. The deformation behavior of the solidifying shell and the possibility of cracking of the strand were also investigated. The recirculating flows were developed in the regions of the web and the flange tip. The impinging of the inlet flow from the nozzle retarded the growing of solidifying shell in the regions of the fillet and the flange. The air gap between the strand and the mold was formed near the region of the corner of the flange tip. At the initial stage of casting, the probability of the surface cracking was high in the regions of the fillet and the flange tip. After the middle stage of casting, the internal cracking was predicted in the regions of the flange tip, and between the fillet and the flange tip. (author) 38

  16. Beam-beam observations in the Relativistic Heavy Ion Collider

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Laboratory (BNL), Upton, NY (United States); White, S. [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2015-06-24

    The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has been operating since 2000. Over the past decade, thanks to the continuously increased bunch intensity and reduced β*s at the interaction points, the maximum peak luminosity in the polarized proton operation has been increased by more than two orders of magnitude. In this article, we first present the beam-beam observations in the previous RHIC polarized proton runs. Then we analyze the mechanisms for the beam loss and emittance growth in the presence of beam-beam interaction. The operational challenges and limitations imposed by beam-beam interaction and their remedies are also presented. In the end, we briefly introduce head-on beam-beam compensation with electron lenses in RHIC.

  17. ICFA Beam Dynamics Newsletter

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi I.; Kuczewski A.; Altinbas, Z.; Beavis, D.; Belomestnykh,; Dai, J. et al

    2012-07-01

    The Collider-Accelerator Department at Brookhaven National Laboratory is building a high-brightness 500 mA capable Energy Recovery Linac (ERL) as one of its main R&D thrusts towards eRHIC, the polarized electron - hadron collider as an upgrade of the operating RHIC facility. The ERL is in final assembly stages, with injection commisioning starting in October 2012. The objective of this ERL is to serve as a platform for R&D into high current ERL, in particular issues of halo generation and control, Higher-Order Mode (HOM) issues, coherent emissions for the beam and high-brightness, high-power beam generation and preservation. The R&D ERL features a superconducting laser-photocathode RF gun with a high quantum efficiency photoccathode served with a load-lock cathode delivery system, a highly damped 5-cell accelerating cavity, a highly flexible single-pass loop and a comprehensive system of beam instrumentation. In this ICFA Beam Dynamics Newsletter article we will describe the ERL in a degree of detail that is not usually found in regular publications. We will discuss the various systems of the ERL, following the electrons from the photocathode to the beam dump, cover the control system, machine protection etc and summarize with the status of the ERL systems.

  18. A better beam quality

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Progress has been made on two fronts, providing physics data and preparing for higher intensities. Over the Whitsun weekend of May 22 to 24, 5 fills for physics provided almost 30 hours of stable colliding beams, all with bunch intensities around 2x1010 protons and at a β* of 2m. The first three of these fills were with 6 bunches per beam, giving 3 pairs of collisions in all experiments. For the other two fills, the number of bunches per beam was increased to 13, giving 8 pairs of colliding bunches, and for the first time luminosities were pushed above 1029 cm-2s-1, 2 orders of magnitude higher than first collisions in March. In between and after these physics fills, nominal bunches of 1011 protons were successfully ramped and brought into collision in ATLAS and CMS for the first time (not in stable beam conditions and without squeeze). Event rates seen by the experiments were in the expected range for these conditions. In the middle of this work, a short fill with beams of 7 nominal bunches was ...

  19. Paul Collier : Balancing beams

    CERN Multimedia

    2009-01-01

    As former head of AB Operations, Paul Collier and his group were in the ‘cockpit’ for the LHC’s maiden voyage - piloting the first beam around the ring. But now, as Head of the Beams Department, he will need his feet firmly on the ground in order to balance all the beam activities at CERN. "As Department Head, I’ll have less direct contact with the machines," Collier says with a hint of regret. "I’ll still obviously be very involved, but they won’t actually let me loose in front of the keyboard anymore!" As the new Head of the BE Department, Collier will be in charge of nearly 400 people, and will oversee all the beam activities, including the preparations for the longest period of beam operation in the history of CERN. In the new organization, the BE, TE and EN Departments have been grouped together in the Accelerator and Technology Sector. "‘Partnership’ is a key word for the three departments," says Collier. "The n...

  20. Beam Time Accounting

    CERN Document Server

    Seitova, Diana

    2016-01-01

    ISOLDE is one of the leading research facilities in the field of nuclear physics. A proton beam with an energy 1.4 GeV coming from the Proton Synchrotron Booster (PSB) hits one of the targets at ISOLDE and produces Radioactive Ion Beams (RIBs). Then, the RIBs of interest is selected and delivered to the different experimental stations. In order to deliver the beam to the certain experimental station, the positions of the devices along the beamline should satisfy certain conditions. The purpose of this project is to define the conditions for the beam to pass through the different beamlines and to store the data about device’s status for later analysis and statistics, so it would be possible to know when the beam was used for different experiments. The data with the settings of the different devices is saved in the Timber database and the first steps for making virtual devices to compile the status of the beamlines were completed.

  1. Bringing up beams

    CERN Multimedia

    Katarina Anthony

    2013-01-01

    Last month, commissioning began on CERN’s newest linear accelerator: Linac4. As the replacement machine for Linac2, Linac4 will take a negative hydrogen ion beam to a staggering 160 MeV. We check in to see how the Linac4 team is preparing its machine for its new role as the first link in the accelerator chain.   The Linac4 3 MeV beam line, with the ion source in the back, the RFQ in the middle and the chopping line in the front. On 14 November, members of the Linac4 collaboration and the CERN Operations Group were brought together for their first “real day” in the Linac4 Control Room. Together, they successfully accelerated their first hydrogen ion beam to 3 MeV. It was an exciting moment for everyone involved and marked the start of one of the most critical commissioning phases for the new accelerator. At the start of the Linac4 beam line sits the CERN-made Radio Frequency Quadrupole (RFQ). This vital piece of machinery takes the beam from 45 keV to 3 MeV in ju...

  2. Thermal analysis of the SSC beam scraper

    Energy Technology Data Exchange (ETDEWEB)

    Tran, N.; Dao, B.

    1993-04-01

    When a particle beam impacts a beam scraper, heat is generated resulting in a rise in the temperature of the material. The maximum temperature rise should be kept to a minimum in order to maintain scraper efficiency and performance. In this paper the results of a thermal analysis of a scraper are presented.

  3. ATA probe beam experiment

    International Nuclear Information System (INIS)

    The philosophy of these tests is to measure the motion of a low current, small diameter electron beam in the accelerator before running high current. By using low current, we can study particle motion in the applied fields without any extra complications associated with the self-forces of high currents. With the steering magnets off, we have measured the transverse drift of the probe beam. Also, we have used the probe beam to optimize the current in the steering magnets to compensate for the drift. There have been concurrent efforts to locate the source of the error field which is presumed to cause the drift. So far, the source has not been established but the search is continuing

  4. Acoustic Tractor Beam

    Science.gov (United States)

    Démoré, Christine E. M.; Dahl, Patrick M.; Yang, Zhengyi; Glynne-Jones, Peter; Melzer, Andreas; Cochran, Sandy; MacDonald, Michael P.; Spalding, Gabriel C.

    2014-05-01

    Negative radiation forces act opposite to the direction of propagation, or net momentum, of a beam but have previously been challenging to definitively demonstrate. We report an experimental acoustic tractor beam generated by an ultrasonic array operating on macroscopic targets (>1 cm) to demonstrate the negative radiation forces and to map out regimes over which they dominate, which we compare to simulations. The result and the geometrically simple configuration show that the effect is due to nonconservative forces, produced by redirection of a momentum flux from the angled sides of a target and not by conservative forces from a potential energy gradient. Use of a simple acoustic setup provides an easily understood illustration of the negative radiation pressure concept for tractor beams and demonstrates continuous attraction towards the source, against a net momentum flux in the system.

  5. Grazing incidence beam expander

    Energy Technology Data Exchange (ETDEWEB)

    Akkapeddi, P.R.; Glenn, P.; Fuschetto, A.; Appert, Q.; Viswanathan, V.K.

    1985-01-01

    A Grazing Incidence Beam Expander (GIBE) telescope is being designed and fabricated to be used as an equivalent end mirror in a long laser resonator cavity. The design requirements for this GIBE flow down from a generic Free Electron Laser (FEL) resonator. The nature of the FEL gain volume (a thin, pencil-like, on-axis region) dictates that the output beam be very small. Such a thin beam with the high power levels characteristic of FELs would have to travel perhaps hundreds of meters or more before expanding enough to allow reflection from cooled mirrors. A GIBE, on the other hand, would allow placing these optics closer to the gain region and thus reduces the cavity lengths substantially. Results are presented relating to optical and mechanical design, alignment sensitivity analysis, radius of curvature analysis, laser cavity stability analysis of a linear stable concentric laser cavity with a GIBE. Fabrication details of the GIBE are also given.

  6. Beam characteristics of energy-matched flattening filter free beams

    Energy Technology Data Exchange (ETDEWEB)

    Paynter, D.; Weston, S. J.; Cosgrove, V. P. [St James Institute of Oncology The Leeds Teaching Hospitals NHS Trust, Medical Physics, Leeds LS9 7TF (United Kingdom); Evans, J. A. [LIGHT Institute University of Leeds Leeds LS2 9JT, Division of Medical Physics, Leeds (United Kingdom); Thwaites, D. I. [LIGHT Institute University of Leeds Leeds LS2 9JT, Division of Medical Physics, Leeds, United Kingdom and Institute of Medical Physics, School of Physics, University of Sydney (Australia)

    2014-05-15

    Purpose: Flattening filter free (FFF) linear accelerators can increase treatment efficiency and plan quality. There are multiple methods of defining a FFF beam. The Elekta control system supports tuning of the delivered FFF beam energy to enable matching of the percentage depth-dose (PDD) of the flattened beam at 10 cm depth. This is compared to FFF beams where the linac control parameters are identical to those for the flattened beam. All beams were delivered on an Elekta Synergy accelerator with an Agility multi-leaf collimator installed and compared to the standard, flattened beam. The aim of this study is to compare “matched” FFF beams to both “unmatched” FFF beams and flattened beams to determine the benefits of matching beams. Methods: For the three modes of operation 6 MV flattened, 6 MV matched FFF, 6 MV unmatched FFF, 10 MV flattened, 10 MV matched FFF, and 10 MV unmatched FFF beam profiles were obtained using a plotting tank and were measured in steps of 0.1 mm in the penumbral region. Beam penumbra was defined as the distance between the 80% and 20% of the normalized dose when the inflection points of the unflattened and flattened profiles were normalized with the central axis dose of the flattened field set as 100%. PDD data was obtained at field sizes ranging from 3 cm × 3 cm to 40 cm × 40 cm. Radiation protection measurements were additionally performed to determine the head leakage and environmental monitoring through the maze and primary barriers. Results: No significant change is made to the beam penumbra for FFF beams with and without PDD matching, the maximum change in penumbra for a 10 cm × 10 cm field was within the experimental error of the study. The changes in the profile shape with increasing field size are most significant for the matched FFF beam, and both FFF beams showed less profile shape variation with increasing depth when compared to flattened beams, due to consistency in beam energy spectra across the radiation field

  7. Optimal beam focusing through turbulence.

    Science.gov (United States)

    Charnotskii, Mikhail

    2015-11-01

    Beam spread and beam wandering are the most perceptible effects of atmospheric turbulence on propagating laser beams. The width of the mean irradiance profile is typically used to characterize the beam spread. This so-called long-term (LT) statistic allows for a relatively simple theoretical description. However, the LT beam size is not a very practical measure of the beam spread because its measurements are sensitive to the movements of the source and detector, and to the large-scale variations of the refractive index that are not associated with turbulence. The short-term (ST) beam spread is measured relative to the instantaneous position of the beam center and is free of these drawbacks, but has not been studied as thoroughly as the LT spread. We present a theoretical model for the ST beam irradiance that is based on the parabolic equation for the beam wave propagation in random media, and the Markov approximation for calculation of the statistics of the optical field, and discuss an approximation that allows introduction of the isoplanatic ST point spread function (PSF). Unlike the LT PSF, the ST PSF depends on the overall beam geometry. This allows optimization of the initial beam field in terms of minimizing the ST beam size at the observation plane. Calculations supporting this conjecture are presented for the simple case of the coherent Gaussian beam, and Kolmogorov turbulence. PMID:26560908

  8. Optimal beam focusing through turbulence.

    Science.gov (United States)

    Charnotskii, Mikhail

    2015-11-01

    Beam spread and beam wandering are the most perceptible effects of atmospheric turbulence on propagating laser beams. The width of the mean irradiance profile is typically used to characterize the beam spread. This so-called long-term (LT) statistic allows for a relatively simple theoretical description. However, the LT beam size is not a very practical measure of the beam spread because its measurements are sensitive to the movements of the source and detector, and to the large-scale variations of the refractive index that are not associated with turbulence. The short-term (ST) beam spread is measured relative to the instantaneous position of the beam center and is free of these drawbacks, but has not been studied as thoroughly as the LT spread. We present a theoretical model for the ST beam irradiance that is based on the parabolic equation for the beam wave propagation in random media, and the Markov approximation for calculation of the statistics of the optical field, and discuss an approximation that allows introduction of the isoplanatic ST point spread function (PSF). Unlike the LT PSF, the ST PSF depends on the overall beam geometry. This allows optimization of the initial beam field in terms of minimizing the ST beam size at the observation plane. Calculations supporting this conjecture are presented for the simple case of the coherent Gaussian beam, and Kolmogorov turbulence.

  9. 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

  10. Euroschool on Exotic Beams

    CERN Document Server

    Pfützner, Marek; The Euroschool on Exotic Beams, vol. IV

    2014-01-01

    This is the forth volume in a series of Lecture Notes based on the highly successful Euro Summer School on Exotic Beams. The aim of these notes is to provide a thorough introduction to radioactive ion-beam physics at the level of graduate students and young postdocs starting out in the field. Each volume covers a range of topics from nuclear theory to experiment and applications. Vol I has been published as LNP 651, Vol II has been published as LNP 700, and Vol. III has been published as LNP 764.

  11. 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.)

  12. Molecular beam epitaxy

    CERN Document Server

    Pamplin, Brian R

    1980-01-01

    Molecular Beam Epitaxy introduces the reader to the use of molecular beam epitaxy (MBE) in the generation of III-V and IV-VI compounds and alloys and describes the semiconductor and integrated optics reasons for using the technique. Topics covered include semiconductor superlattices by MBE; design considerations for MBE systems; periodic doping structure in gallium arsenide (GaAs); nonstoichiometry and carrier concentration control in MBE of compound semiconductors; and MBE techniques for IV-VI optoelectronic devices. The use of MBE to fabricate integrated optical devices and to study semicond

  13. Coherent laser beam combining

    CERN Document Server

    Brignon, Arnaud

    2013-01-01

    Recently, the improvement of diode pumping in solid state lasers and the development of double clad fiber lasers have allowed to maintain excellent laser beam quality with single mode fibers. However, the fiber output power if often limited below a power damage threshold. Coherent laser beam combining (CLBC) brings a solution to these limitations by identifying the most efficient architectures and allowing for excellent spectral and spatial quality. This knowledge will become critical for the design of the next generation high-power lasers and is of major interest to many industrial, environme

  14. Modeling of active beam units with Modelica

    DEFF Research Database (Denmark)

    Maccarini, Alessandro; Hultmark, Göran; Vorre, Anders;

    2015-01-01

    This paper proposes an active beam model suitable for building energy simulations with the programming language Modelica. The model encapsulates empirical equations derived by a novel active beam terminal unit that operates with low-temperature heating and high-temperature cooling systems....... Measurements from a full-scale experiment are used to compare the thermal behavior of the active beam with the one predicted by simulations. The simulation results show that the model corresponds closely with the actual operation. The model predicts the outlet water temperature of the active beam...... with a maximum mean absolute error of 0.18 °C. In term of maximum mean absolute percentage error, simulation results differ by 0.9%. The methodology presented is general enough to be applied for modeling other active beam units. Modeling of active beam units with Modelica. Available from: https...

  15. Experimental Studies on Finite Element Model Updating for a Heated Beam-Like Structure

    Directory of Open Access Journals (Sweden)

    Kaipeng Sun

    2015-01-01

    Full Text Available An experimental study was made for the identification procedure of time-varying modal parameters and the finite element model updating technique of a beam-like thermal structure in both steady and unsteady high temperature environments. An improved time-varying autoregressive method was proposed first to extract the instantaneous natural frequencies of the structure in the unsteady high temperature environment. Based on the identified modal parameters, then, a finite element model for the structure was updated by using Kriging meta-model and optimization-based finite-element model updating method. The temperature-dependent parameters to be updated were expressed as low-order polynomials of temperature increase, and the finite element model updating problem was solved by updating several coefficients of the polynomials. The experimental results demonstrated the effectiveness of the time-varying modal parameter identification method and showed that the instantaneous natural frequencies of the updated model well tracked the trends of the measured values with high accuracy.

  16. Theoretical studies of defect formation and target heating by intense pulsed ion beams

    Science.gov (United States)

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

    2015-11-01

    We present results of three studies related to experiments on NDCX-II, the Neutralized Drift Compression Experiment, a short-pulse (~ 1ns), high-current (~ 70A) linear accelerator for 1.2 MeV ions at LBNL. These include: (a) Coupled transverse and longitudinal envelope calculations of the final non-neutral ion beam transport, followed by neutralized drift and final focus, for a number of focus and drift lengths and with a series of ion species (Z =1-19). Predicted target fluences were obtained and target temperatures in the 1 eV range estimated. (b) HYDRA simulations of the target response for Li and He ions and for Al and Au targets at various ion fluences (up to 1012 ions/pulse/mm2) and pulse durations, benchmarking temperature estimates from the envelope calculations. (c) Crystal-Trim simulations of ion channeling through single-crystal lattices, with comparisons to ion transmission data as a function of orientation angle of the crystal foil and for different ion intensities and ion species. This work was performed under the auspices of the U.S. DOE under contracts DE-AC52-07NA27344 (LLNL), DE-AC02-05CH11231 (LBNL) and DE-AC02-76CH0307 (PPPL) and was supported by the US DOE Office of Science, Fusion Energy Sciences. LLNL-ABS-67521.

  17. Tractor beams for optical micromanipulation

    Science.gov (United States)

    Yevick, Aaron; Grier, David G.

    2016-03-01

    Tractor beams are traveling waves that transport illuminated objects in the retrograde direction relative to the direction of propagation. The theory of photokinetic effects identifies design criteria for long-range general- purpose tractor beams. These criteria distinguish first-order tractor beams that couple to induced dipole moments from higher-order tractor beams that rely on coupling to higher-order multipole moments to achieve pulling. First-order tractor beams are inherently longer-ranged and operate on a wider variety of materials. We explore the physics of first-order tractor beams in the context of a family of generalized solenoidal waves.

  18. Flare plasma dynamics obseved with the YOHKOH Bragg crystal spectrometer. III. Spectral signatures of electron-beam-heated atmospheres.

    Science.gov (United States)

    Marriska, John. T.

    1995-05-01

    Using numerical simulations of an electon-beam-heated solar flare, we investigate the observational consequences of variations in the electron beam total energy flux and the low-energy cut off value for models with both low and high initial densities. To do this we use the evolution of the physical parameters of the simulated flares to synthesize the time evolution of the spectrum in the wavelength region surrounding tha Ca xix resonance line. These spectra are then summed over a 9 s time interval to simulate typical spectra from the Yohkoh Bragg crystal spectometer and the first three moments are computed for comparison with observational results. This comparison shows that no single low or high initial density model satisfies the observed average behavior of the Ca xix resonance line. Low initial density models produce too large a blue shift velocity, while high initial density model have lines that are too narrow. Comparison of these models with the Yohkok data suggests that the key problem for models of the impulsive phase ofa solar flare is producing significant amounts of stationary hot plasma early in the flare.

  19. 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.

  20. Effect of gas heating on the generation of an ultrashort avalanche electron beam in the pulse-periodic regime

    Science.gov (United States)

    Baksht, E. Kh.; Burachenko, A. G.; Lomaev, M. I.; Sorokin, D. A.; Tarasenko, V. F.

    2015-07-01

    The generation of an ultrashort avalanche electron beam (UAEB) in nitrogen in the pulse-periodic regime is investigated. The gas temperature in the discharge gap of the atmospheric-pressure nitrogen is measured from the intensity distribution of unresolved rotational transitions ( C 3Π u , v' = 0) → ( B 3Π g , v″ = 0) in the nitrogen molecule for an excitation pulse repetition rate of 2 kHz. It is shown that an increase in the UAEB current amplitude in the pulse-periodic regime is due to gas heating by a series of previous pulses, which leads to an increase in the reduced electric field strength as a result of a decrease in the gas density in the zone of the discharge formation. It is found that in the pulse-periodic regime and the formation of the diffuse discharge, the number of electrons in the beam increases by several times for a nitrogen pressure of 9 × 103 Pa. The dependences of the number of electrons in the UAEB on the time of operation of the generator are considered.

  1. Effects of Transverse Beam Size in Beam Position Monitors

    CERN Document Server

    Kurennoy, S S

    2001-01-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by a displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those produced by a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.

  2. Effects of transverse beam size in beam position monitors.

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S. (Sergey)

    2001-01-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.

  3. EFFECTS OF TRANSFERSE BEAM SIZE IN BEAM POSITIONS MONITORS

    Energy Technology Data Exchange (ETDEWEB)

    S.S. KURENNOY

    2001-06-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.

  4. Beam Loss and Beam Shape at the LHC Collimators

    CERN Document Server

    Burkart, Florian

    In this master thesis the beam loss and the beam shape at the LHC collimators was measured, analysed, presented and discussed. Beginning with a short introduction of the LHC, the experiments, the supercon- ducting magnet system, the basics on linear beam dynamics and a describtion of the LHC collimation system are given. This is followed by the presentation of the performance of the LHC collimation sys- tem during 2011. A method to convert the Beam Loss Monitor signal in Gy/s to a proton beam loss rate will be introduced. Also the beam lifetime during the proton physics runs in 2011 will be presented and discussed. Finally, the shape of the LHC beams is analysed by using data obtained by scraping the beam at the LHC primary collimators.

  5. High current beam transport with multiple beam arrays

    International Nuclear Information System (INIS)

    Highlights of recent experimental and theoretical research progress on the high current beam transport of single and multiple beams by the Heavy Ion Fusion Accelerator Research (HIFAR) group at the Lawrence Berkeley Laboratory (LBL) are presented. In the single beam transport experiment (SBTE), stability boundaries and the emittance growth of a space charge dominated beam in a long quadrupole transport channel were measured and compared with theory and computer simulations. Also, a multiple beam ion induction linac (MBE-4) is being constructed at LBL which will permit study of multiple beam transport arrays, and acceleration and bunch length compression of individually focused beamlets. Various design considerations of MBE-4 regarding scaling laws, nonlinear effects, misalignments, and transverse and longitudinal space charge effects are summarized. Some aspects of longitudinal beam dynamics including schemes to generate the accelerating voltage waveforms and to amplify beam current are also discussed

  6. Approximating ambient D-region electron densities using dual-beam HF heating experiments at the high-frequency Active Auroral Research Program (HAARP)

    Science.gov (United States)

    Agrawal, Divya

    Dual-beam ELF/VLF wave generation experiments performed at the High-frequency Active Auroral Research Program (HAARP) HF transmitter in Gakona, Alaska are critically compared with the predictions of a newly developed ionospheric high frequency (HF) heating model that accounts for the simultaneous propagation and absorption of multiple HF beams. The dual-beam HF heating experiments presented herein consist of two HF beams transmitting simultaneously: one amplitude modulated (AM) HF beam modulates the conductivity of the lower ionosphere in the extremely low frequency (ELF, 30 Hz to 3 kHz) and/or very low frequency (VLF, 3 kHz to 30 kHz) band while a second HF beam broadcasts a continuous waveform (CW) signal, modifying the efficiency of ELF/VLF conductivity modulation and thereby the efficiency of ELF/VLF wave generation. Ground-based experimental observations are used together with the predictions of the theoretical model to identify the property of the received ELF/VLF wave that is most sensitive to the effects of multi-beam HF heating, and that property is determined to be the ELF/VLF signal magnitude. The dependence of the generated ELF/VLF wave magnitude on several HF transmission parameters (HF power, HF frequency, and modulation waveform) is then experimentally measured and analyzed within the context of the multi-beam HF heating model. For all cases studied, the received ELF/VLF wave magnitude as a function of transmission parameter is analyzed to identify the dependence on the ambient D-region electron density (Ne) and/or electron temperature ( Te), in turn identifying the HF transmission parameters that provide significant independent information regarding the ambient conditions of the D-region ionosphere. A theoretical analysis is performed to determine the conditions under which the effects of Ne and Te can be decoupled, and the results of this analysis are applied to identify an electron density profile that can reproduce the unusually high level of ELF

  7. Beam transport elements

    CERN Multimedia

    1965-01-01

    Two of the beam transport elements for the slow ejection system. On the left, a quadrupole 1.2 m long with a 5 cm aperture, capable of producing a gradient of 5000 gauss. On the right, a 1 m bending magnet with a 4 cm gap; its field is 20 000 gauss.

  8. Candlestick rubidium beam source

    Science.gov (United States)

    Walkiewicz, M. R.; Fox, P. J.; Scholten, R. E.

    2000-09-01

    We describe a long-lived, bright and intense rubidium atomic beam source based on a previously published recirculating candlestick design for sodium, with several modifications and enhancements. The device operates for thousands of hours without maintenance, with brightness of 1.9×1022 m-2 s-1 sr-1.

  9. LHC Report: Beam on

    CERN Multimedia

    Rossano Giachino for the LHC Team

    2012-01-01

    The powering tests described in the last edition of the Bulletin were successfully finished at the end of the first week of March opening the way for 4 TeV operations this year. The beam was back in the machine on Wednesday 14 March. The first collisions at 4 TeV are scheduled for the first week of April.   The first beam of 2012 is dumped after making a few rounds in the LHC. The magnet powering tests were followed by the machine checkout phase. Here the operations team in collaboration with the equipment groups performs a sequence of tests to ensure the readiness of the LHC for beam. The tests include driving all the LHC systems – beam dump, injection, collimation, RF, power converters, magnet circuits, vacuum, interlocks, controls, timing and synchronization – through the operational cycle. The “checkout phase” is really a massive de-bugging exercise, which is performed with the objective of ensuring the proper functioning of the whole machine and t...

  10. Ion-beam technologies

    Energy Technology Data Exchange (ETDEWEB)

    Fenske, G.R. [Argonne National Lab., IL (United States)

    1993-01-01

    This compilation of figures and diagrams reviews processes for depositing diamond/diamond-like carbon films. Processes addressed are chemical vapor deposition (HFCVD, PACVD, etc.), plasma vapor deposition (plasma sputtering, ion beam sputtering, evaporation, etc.), low-energy ion implantation, and hybrid processes (biased sputtering, IBAD, biased HFCVD, etc.). The tribological performance of coatings produced by different means is discussed.

  11. Charged particle beams

    CERN Document Server

    Humphries, Stanley

    2013-01-01

    Detailed enough for a text and sufficiently comprehensive for a reference, this volume addresses topics vital to understanding high-power accelerators and high-brightness-charged particle beams. Subjects include stochastic cooling, high-brightness injectors, and the free electron laser. Humphries provides students with the critical skills necessary for the problem-solving insights unique to collective physics problems. 1990 edition.

  12. Beam catcher/dump

    International Nuclear Information System (INIS)

    A simple, low cost aperture limiting device with an absorber block has been developed and installed in the AGS ring at Brookhaven National Laboratory. The device intercepts injection tails, transition losses, and the inward spiraling beam of an aborted accelerations or extraction cycle. The resultant consolidation of losses at one point reduces activation of components around the ring and radiation exposure to personnel

  13. Beam dumping at ISABELLE

    International Nuclear Information System (INIS)

    Safely ejecting the approx. 40 MJ stored energy per beam at ISABELLE is clearly a major problem, both for experimental apparatus and for superconducting magnets. Intensive study of this problem is just beginning. A brief review of the current status is presented

  14. Recycled Paper Beam Sculpture

    Science.gov (United States)

    Keller, Kristin; Tabacchi, Jo

    2011-01-01

    As art department budgets across the country continue to shrink, art teachers are increasingly on the lookout for inexpensive materials that can be used to teach a range of concepts. In this article, the authors describe a newspaper beam tower project inspired by the book, "The Wonderful Towers of Watts" by Patricia Zelver. There are many more…

  15. Mode Gaussian beam tracing

    CERN Document Server

    Trofimov, M Yu; Kozitskiy, S B

    2015-01-01

    An adiabatic mode Helmholtz equation for 3D underwater sound propagation is developed. The Gaussian beam tracing in this case is constructed. The test calculations are carried out for the crosswedge benchmark and proved an excellent agreement with the source images method.

  16. Observations of the beam-beam interaction in hadron colliders

    International Nuclear Information System (INIS)

    This paper has three parts. In the first part the basic beam-beam theory will be reviewed. Theoretical issues relevant to e+e- colliders will not be mentioned. In the second part we summarize the operational experiences at FERMILAB and CERN. In the last part of the paper, experiments on long-range beam-beam interactions in the TEVATRON are reviewed. (orig./BBOE)

  17. ALCBEAM - Neutral beam formation and propagation code for beam-based plasma diagnostics

    Science.gov (United States)

    Bespamyatnov, I. O.; Rowan, W. L.; Liao, K. T.

    2012-03-01

    ALCBEAM is a new three-dimensional neutral beam formation and propagation code. It was developed to support the beam-based diagnostics installed on the Alcator C-Mod tokamak. The purpose of the code is to provide reliable estimates of the local beam equilibrium parameters: such as beam energy fractions, density profiles and excitation populations. The code effectively unifies the ion beam formation, extraction and neutralization processes with beam attenuation and excitation in plasma and neutral gas and beam stopping by the beam apertures. This paper describes the physical processes interpreted and utilized by the code, along with exploited computational methods. The description is concluded by an example simulation of beam penetration into plasma of Alcator C-Mod. The code is successfully being used in Alcator C-Mod tokamak and expected to be valuable in the support of beam-based diagnostics in most other tokamak environments. Program summaryProgram title: ALCBEAM Catalogue identifier: AEKU_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKU_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 66 459 No. of bytes in distributed program, including test data, etc.: 7 841 051 Distribution format: tar.gz Programming language: IDL Computer: Workstation, PC Operating system: Linux RAM: 1 GB Classification: 19.2 Nature of problem: Neutral beams are commonly used to heat and/or diagnose high-temperature magnetically-confined laboratory plasmas. An accurate neutral beam characterization is required for beam-based measurements of plasma properties. Beam parameters such as density distribution, energy composition, and atomic excited populations of the beam atoms need to be known. Solution method: A neutral beam is initially formed as an ion beam which is extracted from

  18. Strength Evaluation of Heat Affected Zone in Electron Beam Welded ARAA for HCCR TBM in ITER

    International Nuclear Information System (INIS)

    The Korean helium cooled ceramic reflector (HCCR) test blanket module (TBM) has been developed for ITER, and Korean reduced activation ferritic martensitic (RAFM) steel, called advanced reduced activation alloy (ARAA), has also been developed for a structural material of the HCCR TBM. One case of limited optimized electron beam (EB) welding conditions was selected based on previous work, and the weldability of an EB weld was evaluated for TBM fabrication. The micro-hardness was measured from the base to the weld region, and the microstructures were also observed. A small punch (SP) test considering the HAZ was carried out at room and high (550 .deg. C) temperatures. The empirical mechanical properties of HAZ in the EB weld were evaluated, and the fracture behavior was investigated after the SP test. The SP results show that the estimated yield and tensile strength of the HAZ were higher than the base metal at both temperatures. Korean RAFM steel, ARAA, was developed as a TBM structural material. Using one of the program alloys in ARAA (F206), one case of a limited optimized EB welding condition was selected based on previous works, and the weldability of an EB weld using the SP test was evaluated for TBM fabrication at room and high (550 .deg. C) temperatures. From a micro-Vickers hardness evaluation, the HAZ gave the highest values compared with the other regions. The irregular grain boundaries in the HAZ were observed, but its width was narrower than the TIG weld from the previous results. The optimized welding methods such as the TIG, EB, and laser weld, and the welding procedure considering the PWHT are being established, and the weldability evaluation is also progressing according to the development of the ARAA for the fusion material application in Korea

  19. Depth-controlled Bessel beams

    CERN Document Server

    Müller, Angelina; Wallrabe, Ulrike

    2016-01-01

    We present a ring aperture with independently switchable segments for the three-dimensional control of quasi propagation invariant beams. We demonstrate that our liquid crystal design concept preserves coherence and generates the Bessel beam structure.

  20. Intense electron and ion beams

    CERN Document Server

    Molokovsky, Sergey Ivanovich

    2005-01-01

    Intense Ion and Electron Beams treats intense charged-particle beams used in vacuum tubes, particle beam technology and experimental installations such as free electron lasers and accelerators. It addresses, among other things, the physics and basic theory of intense charged-particle beams; computation and design of charged-particle guns and focusing systems; multiple-beam charged-particle systems; and experimental methods for investigating intense particle beams. The coverage is carefully balanced between the physics of intense charged-particle beams and the design of optical systems for their formation and focusing. It can be recommended to all scientists studying or applying vacuum electronics and charged-particle beam technology, including students, engineers and researchers.

  1. Effect of heating samples during pulsed electron beam annealing on the open-circuit voltage of silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Laugier, A.; Barbier, D.; Doghmane, M.S.; Chemisky, G. (Institut National des Sciences Appliquees de Lyon, 69 - Villeurbanne (France))

    1983-01-01

    Defects associated with pulsed electron beam annealing of P implanted Si solar cells lead to poor Vsub(oc) (< 500mV). Their nature is discussed on the basic of S.E.M. observations, deep level transient spectroscopy study and degradation of electrical characteristics of Schottky barriers. An improved pulsed electron beam annealing process is determined, characterized by a low mean energy electron beam (10 keV) associated to a starting temperature of 450/sup 0/C and low fluences (<= 1J/cm/sup 2/). Values of Vsub(oc) similar to conventional thermal annealing are obtained.

  2. A beam source model for scanned proton beams

    Science.gov (United States)

    Kimstrand, Peter; Traneus, Erik; Ahnesjö, Anders; Grusell, Erik; Glimelius, Bengt; Tilly, Nina

    2007-06-01

    A beam source model, i.e. a model for the initial phase space of the beam, for scanned proton beams has been developed. The beam source model is based on parameterized particle sources with characteristics found by fitting towards measured data per individual beam line. A specific aim for this beam source model is to make it applicable to the majority of the various proton beam systems currently available or under development, with the overall purpose to drive dose calculations in proton beam treatment planning. The proton beam phase space is characterized by an energy spectrum, radial and angular distributions and deflections for the non-modulated elementary pencil beam. The beam propagation through the scanning magnets is modelled by applying experimentally determined focal points for each scanning dimension. The radial and angular distribution parameters are deduced from measured two-dimensional fluence distributions of the elementary beam in air. The energy spectrum is extracted from a depth dose distribution for a fixed broad beam scan pattern measured in water. The impact of a multi-slab range shifter for energy modulation is calculated with an own Monte Carlo code taking multiple scattering, energy loss and straggling, non-elastic and elastic nuclear interactions in the slab assembly into account. Measurements for characterization and verification have been performed with the scanning proton beam system at The Svedberg Laboratory in Uppsala. Both in-air fluence patterns and dose points located in a water phantom were used. For verification, dose-in-water was calculated with the Monte Carlo code GEANT 3.21 instead of using a clinical dose engine with approximations of its own. For a set of four individual pencil beams, both with the full energy and range shifted, 96.5% (99.8%) of the tested dose points satisfied the 1%/1 mm (2%/2 mm) gamma criterion.

  3. Cold and Slow Molecular Beam

    OpenAIRE

    Rasmussen, Julia; Patterson, Dave; Lu, Hsin-I; Wright, Matthew; Doyle, John M.

    2011-01-01

    Employing a two-stage cryogenic buffer gas cell, we produce a cold, hydrodynamically extracted beam of calcium monohydride molecules with a near effusive velocity distribution. Beam dynamics, thermalization and slowing are studied using laser spectroscopy. The key to this hybrid, effusive-like beam source is a “slowing cell” placed immediately after a hydrodynamic, cryogenic source [Patterson et al., J. Chem. Phys., 2007, 126, 154307]. The resulting CaH beams are created in two regimes. In on...

  4. Polarized atomic beams for targets

    International Nuclear Information System (INIS)

    The basic principle of the production of polarized atomic hydrogen and deuterium beams are reviewed. The status of the present available polarization, density and intensity are presented. The improvement of atomic beam density by cooling the hydrogen atoms to low velocity is discussed. The possible use of polarized atomic beams as targets in storage rings is shown. It is proposed that polarized atomic beams can be used to produce polarized gas targets with high polarization and greatly improved density

  5. Resolving two beams in beam splitters with a beam position monitor

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S. (Sergey)

    2002-01-01

    The beam transport system for the Advanced Hydrotest Facility (AHF) anticipates multiple beam splitters. Monitoring two separated beams in a common beam pipe in the splitter sections imposes certain requirements on diagnostics for these sections. In this note we explore a two-beam system in a generic beam monitor and study the feasibility of resolving the positions of the two beams with a single diagnostic device. In the Advanced Hydrotest Facility (AHF), 20-ns beam pulses (bunches) are extracted from the 50-GeV main proton synchrotron and then are transported to the target by an elaborated transport system. The beam transport system splits the beam bunches into equal parts in its splitting sections so that up to 12 synchronous beam pulses can be delivered to the target for the multi-axis proton radiography. Information about the transverse positions of the beams in the splitters, and possibly the bunch longitudinal profile, should be delivered by some diagnostic devices. Possible candidates are the circular wall current monitors in the circular pipes connecting the splitter elements, or the conventional stripline BPMs. In any case, we need some estimates on how well the transverse positions of the two beams can be resolved by these monitors.

  6. Cherenkov light-based beam profiling for ultrarelativistic electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Adli, E., E-mail: Erik.Adli@fys.uio.no [Department of Physics, University of Oslo, N-0316 Oslo (Norway); SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Gessner, S.J.; Corde, S.; Hogan, M.J. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Bjerke, H.H. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)

    2015-05-21

    We describe a beam profile monitor design based on Cherenkov light emitted from a charged particle beam in an air gap. The main components of the profile monitor are silicon wafers used to reflect Cherenkov light onto a camera lens system. The design allows for measuring large beam sizes, with large photon yield per beam charge and excellent signal linearity with beam charge. The profile monitor signal is independent of the particle energy for ultrarelativistic particles. Different design and parameter considerations are discussed. A Cherenkov light-based profile monitor has been installed at the FACET User Facility at SLAC. We report on the measured performance of this profile monitor.

  7. Luminosity dilution due to random offset beam-beam interaction

    International Nuclear Information System (INIS)

    We consider beam-beam interaction in a collider in the case when the beams randomly displace around the equilibrium orbit at the interaction point. Due to the random part of the interaction, particles diffuse over the betatron amplitude causing an emittance growth of the beam. A Fokker-Planck equation is derived in which a diffusion coefficient is related with the spectral density of the noise. Estimations for the Superconducting Super Collider parameters give a tolerable level of the high-frequency beam offset at the interaction point. 2 refs

  8. North American radioactive beam initiatives

    International Nuclear Information System (INIS)

    After a brief review of existing radioactive beam facilities in North America, two new initiative (the Oak Ridge Radioactive Ion Beam Facility and the IsoSpin Laboratory) are described in some detail. An evaluation of which nuclei these facilities will be able to study, that cannot be studied with stable targets and beams, also is presented

  9. Nuclear physics with radioactive beams

    International Nuclear Information System (INIS)

    Radioactive beam production through two different mechanisms: acceleration of radioactive nuclei, and production of secondary beams from projectile fragmentation is overviewed. Some topics of the applications of radioactive beams in nuclear physics, such as identification and study of exotic nuclei, neutron halos, nuclear astrophysics and medical applications are discussed. (K.A.). 24 refs., 8 figs

  10. Steady state neutral beam injector

    International Nuclear Information System (INIS)

    Learning from operational reliability of neutral beam injectors in particular and various heating schemes including RF in general on TFTR, JET, JT-60, it has become clear that neutral beam injectors may find a greater role assigned to them for maintaining the plasma in steady state devices under construction. Many technological solutions, integrated in the present day generation of injectors have given rise to capability of producing multimegawatt power at many tens of kV. They have already operated for integrated time >105 S without deterioration in the performance. However, a new generation of injectors for steady state devices have to address to some basic issues. They stem from material erosion under particle bombardment, heat transfer > 10 MW/m2, frequent regeneration of cryopanels, inertial power supplies, data acquisition and control of large volume of data. Some of these engineering issues have been addressed to in the proposed neutral beam injector for SST-1 at our institute; the remaining shall have to wait for the inputs of the database generated from the actual experience with steady state injectors. (author)

  11. Isotropic beam bouquets for shaped beam linear accelerator radiosurgery

    Science.gov (United States)

    Wagner, Thomas H.; Meeks, Sanford L.; Bova, Frank J.; Friedman, William A.; Buatti, John M.; Bouchet, Lionel G.

    2001-10-01

    In stereotactic radiosurgery and radiotherapy treatment planning, the steepest dose gradient is obtained by using beam arrangements with maximal beam separation. We propose a treatment plan optimization method that optimizes beam directions from the starting point of a set of isotropically convergent beams, as suggested by Webb. The optimization process then individually steers each beam to the best position, based on beam's-eye-view (BEV) critical structure overlaps with the target projection and the target's projected cross sectional area at each beam position. This final optimized beam arrangement maintains a large angular separation between adjacent beams while conformally avoiding critical structures. As shown by a radiosurgery plan, this optimization method improves the critical structure sparing properties of an unoptimized isotropic beam bouquet, while maintaining the same degree of dose conformity and dose gradient. This method provides a simple means of designing static beam radiosurgery plans with conformality indices that are within established guidelines for radiosurgery planning, and with dose gradients that approach those achieved in conventional radiosurgery planning.

  12. Beam-beam simulation code BBSIM for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung J.; Sen, Tanaji; /Fermilab

    2011-01-01

    A highly efficient, fully parallelized, six-dimensional tracking model for simulating interactions of colliding hadron beams in high energy ring colliders and simulating schemes for mitigating their effects is described. The model uses the weak-strong approximation for calculating the head-on interactions when the test beam has lower intensity than the other beam, a look-up table for the efficient calculation of long-range beam-beam forces, and a self-consistent Poisson solver when both beams have comparable intensities. A performance test of the model in a parallel environment is presented. The code is used to calculate beam emittance and beam loss in the Tevatron at Fermilab and compared with measurements. They also present results from the studies of stwo schemes proposed to compensate the beam-beam interactions: (a) the compensation of long-range interactions in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven and the Large Hadron Collider (LHC) at CERN with a current carrying wire, (b) the use of a low energy electron beam to compensate the head-on interactions in RHIC.

  13. Definition of Beam Diameter for Electron Beam Welding

    International Nuclear Information System (INIS)

    It is useful to characterize the dimensions of the electron beam during process development for electron beam welding applications. Analysis of the behavior of electron beam welds is simplest when a single number can be assigned to the beam properties that describes the size of the beam spot; this value we generically call the 'beam diameter'. This approach has worked well for most applications and electron beam welding machines with the weld dimensions (width and depth) correlating well with the beam diameter. However, in recent weld development for a refractory alloy, Ta-10W, welded with a low voltage electron beam machine (LVEB), it was found that the weld dimensions (weld penetration and weld width) did not correlate well with the beam diameter and especially with the experimentally determined sharp focus point. These data suggest that the presently used definition of beam diameter may not be optimal for all applications. The possible reasons for this discrepancy and a suggested possible alternative diameter definition is the subject of this paper.

  14. Definition of Beam Diameter for Electron Beam Welding

    Energy Technology Data Exchange (ETDEWEB)

    Burgardt, Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pierce, Stanley W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dvornak, Matthew John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-11

    It is useful to characterize the dimensions of the electron beam during process development for electron beam welding applications. Analysis of the behavior of electron beam welds is simplest when a single number can be assigned to the beam properties that describes the size of the beam spot; this value we generically call the “beam diameter”. This approach has worked well for most applications and electron beam welding machines with the weld dimensions (width and depth) correlating well with the beam diameter. However, in recent weld development for a refractory alloy, Ta-10W, welded with a low voltage electron beam machine (LVEB), it was found that the weld dimensions (weld penetration and weld width) did not correlate well with the beam diameter and especially with the experimentally determined sharp focus point. These data suggest that the presently used definition of beam diameter may not be optimal for all applications. The possible reasons for this discrepancy and a suggested possible alternative diameter definition is the subject of this paper.

  15. From Electron Beams to Photon Beams

    International Nuclear Information System (INIS)

    n this article I try to report at the best the events and the emotions I experienced, together with my colleagues, when I was a young researcher working at the Frascati Center of CNEN. In the middle of 70’s the high energy physics activities carried out in Frascati were transferred from CNEN to INFN (Istituto Nazionale Fisica Nucleare) and the personnel had the chance to chose to continue to work at the CNEN (obviously in a different research field) or to continue to work in high energy physics, but at the INFN. I decided to remain at the CNEN and, consequently, I had to change my research activity. I moved from the high energy accelerators research field to the lasers research field in which, at that time at the CNEN, a new interesting project on “uranium laser isotope separation” was just starting. This article is focused on the theoretical and experimental development activity, carried out in the years 70’s-80’s at the CNEN Frascati Center, on a quite particular kind of laser to be utilized in that project. In this laser the active medium is not made of atoms or molecules but is a beam of free electrons running along a spatially periodic magnetic structure: this laser is the “Free Electron Laser”

  16. LEDA beam diagnostics instrumentation: Beam current measurement

    International Nuclear Information System (INIS)

    The Low Energy Demonstration Accelerator (LEDA) facility located at Los Alamos National Laboratory (LANL) accelerates protons to an energy of 6.7 MeV and current of 100 mA operating in either a pulsed or cw mode. Two types of current measurements are used. The first is an AC or pulsed-current measurement which uses three LANL built toroids. They are placed in the beamline in such a way as to measure important transmission parameters and act as a differential current-loss machine protection system. The second system is a DC current measurement used to measure cw beam characteristics and uses toroids from Bergoz Inc. There are two of these systems, so they can also be used for transmission measurements. The AC system uses custom processing electronics whereas the DC system uses a modified Bergoz registered electronics system. Both systems feature data acquisition via a series of custom TMS320C40 Digital Signal Processing (DSP) boards. Of special interest to this paper is the operation of these systems, the calibration technique, the differential current loss measurements and fast-protection processing, current droop characteristics for the AC system, and existing system noise levels. This paper will also cover the DSP system operations and their interaction with the main accelerator control system

  17. Square shaped flat-top beam in refractive beam shapers

    Science.gov (United States)

    Laskin, Alexander; Laskin, Vadim; Ostrun, Aleksei

    2015-08-01

    Lossless transformation of round Gaussian to square shaped flat-top collimated beam is important in building highpower solid state laser systems to improve optical pumping or amplification. There are industrial micromachining applications like scribing, display repair, which performance is improved when a square shaped spot with uniform intensity is created. Proved beam shaping solutions to these techniques are refractive field mapping beam shapers having some important features: flatness of output phase front, small output divergence, high transmittance, extended depth of field, operation with TEM00 and multimode lasers. Usual approach to design refractive beam shapers implies that input and output beams have round cross-section, therefore the only way to create a square shaped output beam is using a square mask, which leads to essential losses. When an input laser beam is linearly polarized it is suggested to generate square shaped flat-top output by applying beam shaper lenses from birefringent materials or by using additional birefringent components. Due to birefringence there is introduced phase retardation in beam parts and is realized a square shaped interference pattern at the beam shaper output. Realization of this approach requires small phase retardation, therefore weak birefringence effect is enough and birefringent optical components, operating in convergent or divergent beams, can be made from refractive materials, which crystal optical axis is parallel to optical axis of entire beam shaper optical system. There will be considered design features of beam shapers creating square shaped flat-top beams. Examples of real implementations and experimental results will be presented as well.

  18. Laser beam steering device

    Science.gov (United States)

    Motamedi, M. E.; Andrews, A. P.; Gunning, W. J.

    1993-01-01

    Agile beam steering is a critical requirement for airborne and space based LIDAR and optical communication systems. Design and test results are presented for a compact beam steering device with low inertia which functions by dithering two complementary (positive and negative) binary optic microlens arrays relative to each other in directions orthogonal to the direction of light propagation. The miniaturized system has been demonstrated at scan frequencies as high as 300 Hz, generating a 13 x 13 spot array with a total field of view of 2.4 degrees. The design is readily extendable to a 9.5 degree field of view and a 52 x 52 scan pattern. The system is compact - less than 2 in. on a side. Further size reductions are anticipated.

  19. Neutrino beam plasma instability

    Indian Academy of Sciences (India)

    Vishnu M Bannur

    2001-10-01

    We derive relativistic fluid set of equations for neutrinos and electrons from relativistic Vlasov equations with Fermi weak interaction force. Using these fluid equations, we obtain a dispersion relation describing neutrino beam plasma instability, which is little different from normal dispersion relation of streaming instability. It contains new, nonelectromagnetic, neutrino-plasma (or electroweak) stable and unstable modes also. The growth of the instability is weak for the highly relativistic neutrino flux, but becomes stronger for weakly relativistic neutrino flux in the case of parameters appropriate to the early universe and supernova explosions. However, this mode is dominant only for the beam velocity greater than 0.25 and in the other limit electroweak unstable mode takes over.

  20. Silicon microfabricated beam expander

    Energy Technology Data Exchange (ETDEWEB)

    Othman, A., E-mail: aliman@ppinang.uitm.edu.my; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A. [Faculty of Electrical Engineering, Universiti Teknologi MARA Malaysia, 40450, Shah Alam, Selangor (Malaysia); Ain, M. F. [School of Electrical and Electronic Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300,Nibong Tebal, Pulau Pinang (Malaysia)

    2015-03-30

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  1. Slow light beam splitter.

    Science.gov (United States)

    Xiao, Yanhong; Klein, Mason; Hohensee, Michael; Jiang, Liang; Phillips, David F; Lukin, Mikhail D; Walsworth, Ronald L

    2008-07-25

    We demonstrate a slow light beam splitter using rapid coherence transport in a wall-coated atomic vapor cell. We show that particles undergoing random and undirected classical motion can mediate coherent interactions between two or more optical modes. Coherence, written into atoms via electromagnetically induced transparency using an input optical signal at one transverse position, spreads out via ballistic atomic motion, is preserved by an antirelaxation wall coating, and is then retrieved in outgoing slow light signals in both the input channel and a spatially-separated second channel. The splitting ratio between the two output channels can be tuned by adjusting the laser power. The slow light beam splitter may improve quantum repeater performance and be useful as an all-optical dynamically reconfigurable router.

  2. Determination of Kinetic Parameters and Metal Ions in Urea-Urease System Based on the Biochemical Reaction Heat Induced Laser Beam Deflection

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new analytical method for the determination of urea-urease system based on biochemical reaction heat induced laser beam deflection is presented in this paper. With the method, the Michaelis constant (Km) of urease and apparent inhibition constant (Ki) of some metal ion inhibitors were measured respectively. This method was also used for the quantitative determination of metal ions with satisfactory result.

  3. Performance of Chilled Beam with Radial Swirl Jet and Diffuse Ceiling Air Supply in Heating Mode

    DEFF Research Database (Denmark)

    Bertheussen, Bård; Mustakallio, Panu; Melikov, Arsen Krikor;

    2013-01-01

    ). The room air temperature was kept at 21 °C. Tracer gas was used to simulate pollution from floor and desk. The experimental conditions comprised: 1) night time without heat sources in the room; the room air conditioning system was used to heat up the room; 2) heat load generated by an occupant (simulated...

  4. Laser beam methane detector

    Science.gov (United States)

    Hinkley, E. D., Jr.

    1981-01-01

    Instrument uses infrared absorption to determine methane concentration in liquid natural gas vapor. Two sensors measure intensity of 3.39 mm laser beam after it passes through gas; absorption is proportional to concentration of methane. Instrument is used in modeling spread of LNG clouds and as leak detector on LNG carriers and installations. Unit includes wheels for mobility and is both vertically and horizontally operable.

  5. Proton beam therapy facility

    Energy Technology Data Exchange (ETDEWEB)

    1984-10-09

    It is proposed to build a regional outpatient medical clinic at the Fermi National Accelerator Laboratory (Fermilab), Batavia, Illinois, to exploit the unique therapeutic characteristics of high energy proton beams. The Fermilab location for a proton therapy facility (PTF) is being chosen for reasons ranging from lower total construction and operating costs and the availability of sophisticated technical support to a location with good access to patients from the Chicago area and from the entire nation. 9 refs., 4 figs., 26 tabs.

  6. Proton beam therapy

    OpenAIRE

    Levin, W P; Kooy, H; Loeffler, J S; T. F. DeLaney

    2005-01-01

    Conventional radiation therapy directs photons (X-rays) and electrons at tumours with the intent of eradicating the neoplastic tissue while preserving adjacent normal tissue. Radiation-induced damage to healthy tissue and second malignancies are always a concern, however, when administering radiation. Proton beam radiotherapy, one form of charged particle therapy, allows for excellent dose distributions, with the added benefit of no exit dose. These characteristics make this form of radiother...

  7. Beam-Material Interaction

    CERN Document Server

    Mokhov, N V

    2016-01-01

    Th is paper is motivated by the growing importance of better understanding of the phenomena and consequences of high- intensity energetic particle beam interactions with accelerator, generic target , and detector components. It reviews the principal physical processes of fast-particle interactions with matter, effects in materials under irradiation, materials response, related to component lifetime and performance, simulation techniques, and methods of mitigating the impact of radiation on the components and envir onment in challenging current and future application

  8. Mode Gaussian beam tracing

    Science.gov (United States)

    Trofimov, M. Yu.; Zakharenko, A. D.; Kozitskiy, S. B.

    2016-10-01

    A mode parabolic equation in the ray centered coordinates for 3D underwater sound propagation is developed. The Gaussian beam tracing in this case is constructed. The test calculations are carried out for the ASA wedge benchmark and proved an excellent agreement with the source images method in the case of cross-slope propagation. But in the cases of wave propagation at some angles to the cross-slope direction an account of mode interaction becomes necessary.

  9. Beam-Material Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Mokhov, N. V. [Fermilab; Cerutti, F. [CERN

    2016-01-01

    Th is paper is motivated by the growing importance of better understanding of the phenomena and consequences of high-intensity energetic particle beam interactions with accelerator, generic target, and detector components. It reviews the principal physical processes of fast-particle interactions with matter, effects in materials under irradiation, materials response, related to component lifetime and performance, simulation techniques, and methods of mitigating the impact of radiation on the components and environment in challenging current and future applications.

  10. Electron beams in radiation therapy

    International Nuclear Information System (INIS)

    Clinical electron beams in interaction with beam flattening and collimating devices are studied, in order to obtain the means for adequate electron therapy. A treatment planning method for arbitrary field shapes is developed that takes the properties of the collimated electron beams into account. An electron multiple-scattering model is extended to incorporate a model for the loss of electrons with depth, in order to improve electron beam dose planning. A study of ionisation measurements in two different phantom materials yields correction factors for electron beam dosimetry. (Auth.)

  11. Targets and Secondary Beam Extraction

    Science.gov (United States)

    Noah, Etam

    2014-02-01

    Several applications make use of secondary beams of particles generated by the interaction of a primary beam of particles with a target. Spallation neutrons, bremsstrahlung photon-produced neutrons, radioactive ions and neutrinos are available to users at state-of-the-art facilities worldwide. Plans for even higher secondary beam intensities place severe constraints on the design of targets. This article reports on the main targetry challenges and highlights a variety of solutions for targetry and secondary beam extraction. Issues related to target station layout, instrumentation at the beam-target interface, safety and radioprotection are also discussed.

  12. Hyperon Beam Experiment

    CERN Multimedia

    2002-01-01

    The experiment WA89 uses the upgraded Omega facility together with a hyperon beam installed at the end of the H1 beamline. The beam can deliver 2~10$ ^{5} \\% Sigma ^- $ per machine burst at 330 GeV/c with a background of 5 10$ ^{5} \\% \\pi ^- $. \\\\ \\\\ The goals of the experiment are: observation of charmed particles, mainly the charmed-strange baryons and measurements of their production in the kinematical range x$ _{F} $~$>$~0.2, and their decay properties, a search for exotic states such as U(3100) observed in the previous CERN hyperon beam experiment WA62, measurements of hyperon polarization and production properties. \\\\ \\\\ A vertex detector consisting of 24 silicon microstrip planes with 25~$\\mu$m pitch and 6~planes with 50~$\\mu$m pitch provides track measurements of sufficient accuracy to identify the decays of short living charmed particles and measure their lifetimes. A RICH detector provides good $\\pi$/K separation for momenta up to 100~GeV/c and $\\pi$/p separation up to 150~GeV/c. Photons are detecte...

  13. Beam screen issues

    CERN Document Server

    Métral, E

    2011-01-01

    In the High Energy LHC (HE-LHC), a beam energy of about 16.5 TeV is currently contemplated. The beam screen issues linked to the use of 20 T dipole magnets instead of 8.33 T are discussed, with a particular emphasis on two mechanisms, the magneto-resistance and the anomalous skin effect, assuming the nominal machine and beam parameters. The magneto-resistance effect always leads to an increase of the material resistivity (as the mean free path in the presence of a transverse magnetic field becomes smaller). As concerns the anomalous skin effect, the anomalous increase of surface resistance of metals at low temperatures and high frequencies is attributed to the long mean free path of the conduction electrons: when the skin depth becomes much smaller than the mean free path, only a fraction of the conduction electrons moving almost parallel to the metal surface is effective in carrying the current and the classical theory breaks down.

  14. Neutron beam applications

    International Nuclear Information System (INIS)

    For the materials science by neutron technique, the development of the various complementary neutron beam facilities at horizontal beam port of HANARO and the techniques for measurement and analysis has been performed. High resolution powder diffractometer, after the installation and performance test, has been opened and used actively for crystal structure analysis, magnetic structure analysis, phase transition study, etc., since January 1998. The main components for four circle diffractometer were developed and, after performance test, it has been opened for crystal structure analysis and texture measurement since the end of 1999. For the small angle neutron spectrometer, the main component development and test, beam characterization, and the preliminary experiment for the structure study of polymer have been carried out. Neutron radiography facility, after the precise performance test, has been used for the non-destructive test of industrial component. Addition to the development of main instruments, for the effective utilization of those facilities, the scattering techniques relating to quantitative phase analysis, magnetic structure analysis, texture measurement, residual stress measurement, polymer study, etc, were developed. For the neutron radiography, photographing and printing technique on direct and indirect method was stabilized and the development for the real time image processing technique by neutron TV was carried out. The sample environment facilities for low and high temperature, magnetic field were also developed

  15. Applications of focused ion beams in microelectronics

    International Nuclear Information System (INIS)

    We present the conclusions of the RSRE programme on the application of focused ion beams in microelectronics and review the literature published in this field. We discuss the design and performance of focused beam implanters and the viability of their application to semiconductor device fabrication. Applications in the areas of lithography, direct implantation and micromachining are discussed in detail. Comparisons are made between the use of focused ion beams and existing techniques for these fabrication processes with a strong emphasis placed on the relative throughputs. We present results on a novel spot size measurement technique and the effect of beam heating on resist. We also present the results of studies into implantation passivation of resist to oxygen plasma attack as basis for a dry development lithography scheme. A novel lithography system employing flood electron exposure from a photocathode which is patterned by a focused ion beam which can also be used to repair mask defects is considered. (author)

  16. Electron Beam Welding of Gear Wheels by Splitted Beam

    Science.gov (United States)

    Dřímal, Daniel

    2014-06-01

    This contribution deals with the issue of electron beam welding of high-accurate gear wheels composed of a spur gearing and fluted shaft joined with a face weld for automotive industry. Both parts made of the high-strength low-alloy steel are welded in the condition after final machining and heat treatment, performed by case hardening, whereas it is required that the run-out in the critical point of weldment after welding, i. e. after the final operation, would be 0.04 mm max.. In case of common welding procedure, cracks were formed in the weld, initiated by spiking in the weld root. Crack formation was prevented by the use of an interlocking joint with a rounded recess and suitable welding parameters, eliminating crack initiation by spiking in the weld root. Minimisation of the welding distortions was achieved by the application of tack welding with simultaneous splitting of one beam into two parts in the opposite sections of circumferential face weld attained on the principle of a new system of controlled deflection with digital scanning of the beam. This welding procedure assured that the weldment temperature after welding would not be higher than 400 °C. Thus, this procedure allowed achieving the final run-outs in the critical point of gearwheels within the maximum range up to 0.04 mm, which is acceptable for the given application. Accurate optical measurements did not reveal any changes in the teeth dimensions.

  17. Operational beams for the LHC

    CERN Document Server

    Papaphilippou, Y; Rumolo, G; Manglunki, D

    2014-01-01

    The variety of beams, needed to set-up in the injectors as requested in the LHC, are reviewed, in terms of priority but also performance expectations and reach during 2015. This includes the single bunch beams for machine commissioning and measurements (probe, Indiv) but also the standard physics beams with 50 ns and 25 ns bunch spacing and their high brightness variants using the Bunch Compression Merging and Splitting (BCMS) scheme. The required parameters and target performance of special beams like the doublet for electron cloud enhancement and the more exotic 8b$\\oplus$4e beam, compatible with some post-scrubbing scenarios are also described. The progress and plans for the LHC ion production beams during 2014-2015 are detailed. Highlights on the current progress of the setting up of the various beams are finally presented with special emphasis on potential performance issues across the proton and ion injector chain.

  18. CLIC Drive Beam Phase Stabilisation

    CERN Document Server

    Gerbershagen, Alexander; Schulte, Daniel

    The thesis presents phase stability studies for the Compact Linear Collider (CLIC) and focuses in particular on CLIC Drive Beam longitudinal phase stabilisation. This topic constitutes one of the main feasibility challenges for CLIC construction and is an essential component of the current CLIC stabilisation campaign. The studies are divided into two large interrelated sections: the simulation studies for the CLIC Drive Beam stability, and measurements, data analysis and simulations of the CLIC Test Facility (CTF3) Drive Beam phase errors. A dedicated software tool has been developed for a step-by-step analysis of the error propagation through the CLIC Drive Beam. It uses realistic RF potential and beam loading amplitude functions for the Drive and Main Beam accelerating structures, complete models of the recombination scheme and compressor chicane as well as of further CLIC Drive Beam modules. The tool has been tested extensively and its functionality has been verified. The phase error propagation at CLIC h...

  19. Relativistic electron beams above thunderclouds

    Directory of Open Access Journals (Sweden)

    M. Füllekrug

    2011-05-01

    Full Text Available Non-luminous relativistic electron beams above thunderclouds are detected by radio remote sensing with low frequency radio signals from 40–400 kHz. The electron beams occur 2–9 ms after positive cloud-to-ground lightning discharges at heights between 22–72 km above thunderclouds. The positive lightning discharges also cause sprites which occur either above or before the electron beam. One electron beam was detected without any luminous sprite occurrence which suggests that electron beams may also occur independently. Numerical simulations show that the beamed electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of 7 MeV to transport a total charge of 10 mC upwards. The impulsive current associated with relativistic electron beams above thunderclouds is directed downwards and needs to be considered as a novel element of the global atmospheric electric circuit.

  20. Relativistic electron beams above thunderclouds

    DEFF Research Database (Denmark)

    Füellekrug, M.; Roussel-Dupre, R.; Symbalisty, E. M. D.;

    2011-01-01

    Non-luminous relativistic electron beams above thunderclouds have been detected by the radio signals of low frequency similar to 40-400 kHz which they radiate. The electron beams occur similar to 2-9 ms after positive cloud-to-ground lightning discharges at heights between similar to 22-72 km above...... thunderclouds. Intense positive lightning discharges can also cause sprites which occur either above or prior to the electron beam. One electron beam was detected without any luminous sprite which suggests that electron beams may also occur independently of sprites. Numerical simulations show that beams...... of electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of similar to 7MeV to transport a total charge of similar to-10mC upwards. The impulsive current similar to 3 x 10(-3) Am-2 associated with relativistic electron beams above thunderclouds...

  1. Premature beam dumps in 2011

    CERN Document Server

    Albert, Markus

    2012-01-01

    The statistical analysis of all non-programmed beam dumps during the 2011 proton run is presented. The selection criteria of fills that got considered were that the beam intensity of each of the two beams exceeded at least 1e12 particles per beam in order to exclude all probe beam dumps and most of the MPS test dumps. A distribution of beam dump causes by system is shown, as well as the time it took to re-establish injection after a non-programmed dump for fills which made it into STABLE BEAMS. This was done in an attempt to evaluate the cost of those non-programmed dumps in terms of time.

  2. Combined steady state and high cycle transient heat load simulation with the electron beam facility JUDITH 2

    International Nuclear Information System (INIS)

    The increasing world energy needs lead to strong efforts in today's energy R and D trying to open up new energy resources. One possible option to access energy in large scale power plants is to use the process of nuclear fusion to generate heat and, from that, electricity with conventional steam turbine technology. However, the realisation is technologically and scientifically very challenging. The heat fluxes that load the inner walls of a fusion device, especially the most severely loaded part, the divertor, are one of the issues currently being under investigation. A distinction is made between steady state heat loads (SSHLs) that are continuously active during operation and transient heat loads (THLs) that are superimposed short-time events. The potentially most harmful THLs during normal operation are type I Edge Localised Modes (ELMs). They are estimated to have a power density of 1 - 10 GWm-2 for 0.2 - 0.5 ms duration in the upcoming next step fusion experiment ITER. Because of high pulse repetition frequency more than 106 ELM events are expected during the foreseen lifetime of divertor components. However, only data regarding behaviour of materials for a low number of pulses (typically 100 - 1000) exists. This work describes the development of a procedure to simulate THLs at high repetition frequency using an electron beam facility and the tests done on tungsten and carbon-based (carbon fibre composite, CFC) plasma facing materials. The developed procedure uses a pulse frequency of 25 Hz, hence actively cooled components are necessary and were designed. A novel electron beam guidance procedure, called circular loading method, was a result of the developmental process. It was used for all later tests because it provides a stabilisation of the applied power density against test parameter fluctuations (e.g. vacuum quality). The electron beam guidance is flexible enough to provide a SSHL pattern during the interpulse time (between two successive THLs

  3. Special Technologies Related to Electron Beam Welding

    Institute of Scientific and Technical Information of China (English)

    Zhao; Haiyan; Cai; Zhipeng; Wang; Xichang

    2007-01-01

    In order to improve the manufacturing quality of electron beam welding,some technologies are developed by using the special features of electron beam.Comparing with the conventional electron beam welding,the usage of multi-beam technology and micro-beam technology are introduced.In addition.the development of beam diagnostic system is also presented.

  4. Thermal quadrupole method applied to flat and spherical semi-transparent multilayers heated up with a modulated laser beam

    Science.gov (United States)

    Ordonez-Miranda, J.; Alvarado-Gil, J. J.

    2012-12-01

    The thermal quadrupole method for flat and spherical multilayered systems heated up with a modulated laser beam is developed and analyzed. The obtained results take into account the contribution of the thermal properties and optical absorption coefficient of the component semi-transparent layers as well as their interface thermal resistance, under a fully analytical framework. For opaque layers, they reduced to the results reported in the literature. It is shown that the thermal wave fields for spherical layers reduce to the ones for flat layers, under a proper limit on the radius of the layers. By analyzing the features of the normalized amplitude and phase as a function of the normalized frequency for one- and two-layer systems, simple and useful formulas to determine the optical absorption coefficient of flat and spherical layers are derived. The proposed approach extends the applicability of the thermal quadrupole method to deal with modulated internal heat sources, it allows determining the thermal wave field of any number of layers in a simple way, and therefore, it would be useful to perform the thermal and optical characterization of flat and spherical layered systems by means of photothermal techniques.

  5. Simulating transient effects of pulsed beams on beam intercepting devices

    International Nuclear Information System (INIS)

    The development in the physics community towards higher beam power through the possibilities of particle accelerators lead to challenges for the developers of elements which are exposed to effect of particle beams (beam intercepting devices =BIDs). For the design of BIDs, the increasing heat load onto these devices due to energetic and focused beams and - in most cases - their highly pulsed nature has to be taken into account. The physics requirements are sometimes opposed to the current state of the art. As one possibility of many in combining the different aspects for these ambitious demands, two highly developed computer programs, namely FLUKA and ANSYS AUTODYN, were joined for this dissertation. The former is a widely enhanced Monte-Carlo-code which specializes on the interaction of particles with static matter, while the latter is a versatile explicit code for the simulation of highly dynamic processes. Both computer programs were developed intensively over years and are still continuously enhanced in order to achieve their best potential. As a consequence of their separate development histories, their combination requires a large amount of work - at the physics limits of their application as well as at the frontier of computing technology. The current work did not touch all different points needed for a full integration, but it is a first step towards their coupling within a feasible time frame. For the simulation of metallic targets irradiated with highly energetic uranium ions different material models have been combined and one parameter describing the damage of the material was varied. In the case of two copper targets, this procedure led to a qualitative agreement between simulations and experimental results. (author)

  6. High Heat Flux Testing of B4C/Cu and SiC/Cu Functionally Graded Materials Simulated by Laser and Electron Beam

    Institute of Scientific and Technical Information of China (English)

    刘翔; 谌继明; 张斧; 许增裕; 葛昌纯; 李江涛

    2002-01-01

    B4C, SiC and C, Cu functionally graded-materials (FGMs) have been developed by plasma spraying and hot pressing. Their high-heat flux properties have been investigated by high energy laser and electron beam for the simulation of plasma disruption process of the future fusion reactors, And a study on eroded products of B4C/Cu FGM under transient thermal load of electron beam was performed. In the experiment, SEM and EDS analysis indicated that B4C and SiC were decomposed, carbon was preferentially evaporated under high thermal load, and a part of Si and Cu were melted, in addition, the splash of melted metal and the particle emission of brittle destruction were also found. Different erosive behaviors of carbon-based materials (CBMs) caused by laser and electron beam were also discussed.

  7. High heat flux testing of B4C/Cu and SiC/Cu functionally graded materials simulated by laser and electron beam

    International Nuclear Information System (INIS)

    B4C, SiC and C, Cu functionally graded-materials (FGMs) have been developed by plasma spraying and hot pressing. Their high-heat flux properties have been investigated by high energy laser and electron beam for the simulation of plasma disruption process of the future fusion reactors. And a study on eroded products of B4C/Cu FGM under transient thermal load of electron beam was performed. In the experiment, SEM and EDS analysis indicated that B4C and SiC were decomposed, carbon was preferentially evaporated under high thermal load, and a part of Si and Cu were melted, in addition, the splash of melted metal and the particle emission of brittle destruction were also found. Different erosive behaviors of carbon-based materials (CBMs) caused by laser and electron beam were also discussed

  8. Beam line design using G4BeamLine

    CERN Document Server

    Dogan, Arda

    2014-01-01

    In Turkey in Ankara TAEK SANAEM Proton Accelerator Facility (PAF), there is a cyclotron which produces a focused intense 30 MeV proton beam and sends this beam to four different arms, three of which uses this beam to produce pharmaceutical medicine. The remaining one is spared for R&D purposes and the idea was to use these protons coming out from the fourth arm to use space radiation tests, which cannot be done in Turkey at the moment. However, according to SCC 25100 standards which is for 30 MeV protons, the beam coming out of cyclotron is too intense and focused to use for space radiation tests. Therefore, the main aim of my project is to design a beam line which will defocus the beam and reduce the flux so that the space radiation tests can be done according to the standards of SCC 25100.

  9. LHC Beam Instrumentation: Beam Profile Measurements (2/3)

    CERN Document Server

    CERN. Geneva

    2014-01-01

    The LHC is equipped with a full suite of sophisticated beam instrumentation which has been essential for rapid commissioning, the safe increase in total stored beam power and the understanding of machine optics and accelerator physics phenomena. These lectures will introduce these systems and comment on their contributions to the various stages of beam operation. They will include details on: the beam position system and its use for real-time global orbit feedback; the beam loss system and its role in machine protection; total and bunch by bunch intensity measurements; tune measurement and feedback; diagnostics for transverse beam size measurements, abort gap monitoring and longitudinal density measurements. Issues and problems encountered along the way will also be discussed together with the prospect for future upgrades.

  10. Beam-Beam Effect with an External Noise in LHC

    CERN Document Server

    Ohmi, K; Höfle, Wolfgang; Tomás, R; Zimmermann, F

    2007-01-01

    In absence of synchrotron radiation, proton beams do not have any damping mechanism for incoherent betatron motion. A noise, which kicks beam particles in the transverse plane, gives a coherent betatron amplitude. If the system is linear, the coherent motion is maintained in amplitude. Nonlinear force, beam-beam and beam-electron cloud interactions, cause a decoherence of the betatron motion keeping the amplitude of each beam particle, with the result that an emittance growth arises. We focus only on fast noise with a correlation time of 1-100 turns. Slower noise is less serious, because it is regarded as an adiabatic change like a closed orbit change. As sources of the noise, we consider the bunch by bunch feedback system and phase jitter of cavities which turns to transverse noise via a crab cavity.

  11. Micro-beam XRF localization by a laser beam

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A new method for micro-beam XRF localization is presented. A laserbeam along with an incident X-ray hits on the surface of a sample. The micro region onthe sample that reached by X-ray beam can be localized by means of thevisible spot of the laser beam. This method is suitable for X-ray microprobesusing anX-ray tube or synchrotron radiation as excitation sources.

  12. A laser beam quality definition based on induced temperature rise.

    Science.gov (United States)

    Miller, Harold C

    2012-12-17

    Laser beam quality metrics like M(2) can be used to describe the spot sizes and propagation behavior of a wide variety of non-ideal laser beams. However, for beams that have been diffracted by limiting apertures in the near-field, or those with unusual near-field profiles, the conventional metrics can lead to an inconsistent or incomplete description of far-field performance. This paper motivates an alternative laser beam quality definition that can be used with any beam. The approach uses a consideration of the intrinsic ability of a laser beam profile to heat a material. Comparisons are made with conventional beam quality metrics. An analysis on an asymmetric Gaussian beam is used to establish a connection with the invariant beam propagation ratio.

  13. Beam-Forming Concentrating Solar Thermal Array Power Systems

    Science.gov (United States)

    Cwik, Thomas A. (Inventor); Dimotakis, Paul E. (Inventor); Hoppe, Daniel J. (Inventor)

    2016-01-01

    The present invention relates to concentrating solar-power systems and, more particularly, beam-forming concentrating solar thermal array power systems. A solar thermal array power system is provided, including a plurality of solar concentrators arranged in pods. Each solar concentrator includes a solar collector, one or more beam-forming elements, and one or more beam-steering elements. The solar collector is dimensioned to collect and divert incoming rays of sunlight. The beam-forming elements intercept the diverted rays of sunlight, and are shaped to concentrate the rays of sunlight into a beam. The steering elements are shaped, dimensioned, positioned, and/or oriented to deflect the beam toward a beam output path. The beams from the concentrators are converted to heat at a receiver, and the heat may be temporarily stored or directly used to generate electricity.

  14. Optics and beam guidance

    International Nuclear Information System (INIS)

    This is an introductory manual for the field of particle transport (guiding). The utilized method described is that of classical geometrical optics which is based on the action principle or minimal action principle. This manual is addressed to readers neither specialized or familiar with intricate computations. The treatment is focussed upon the transport line of an experimental beam conceived for the late-project PIAFE. This case was chosen as it poses and solves certain significant difficult issues. In addition it will also allow in course of exposition to illustrate formulas and properties and also to give orders of magnitude. Background notions are given on: forces, curvature radius, potential, energy and units. The frame of conception is defined by means of the concepts of particle, referential trajectory, emittance, quadrupoles, electrostatic lenses, etc. Simulation for a large number of systems can be done with fairly high accuracy with the aid of thin lenses. Consequently the properties of several assemblies as for instance the periodic system 'FODO' are studied on the case of a single particle and emittance by means of adaptation and stability notions. The manual is structured on the following sections: 1. Introduction; 2. Basic notions; 3. Particle trajectories; 4. The real beam. Emittance and Evolution; 5.Optics notions and applications; 6. Elements of focusing; 7. Particle beam bending; 8. Some items presented in annexes and conclusions. In annexes the following important technical issues are addressed: 1. Effects of alignment failures on PIAFE structure trajectories; 2. Alignment. Phase 1: Magnetic centers and quadrupoles; 3. Alignment. Phase 2: Structures; 4. Residual gas/ Required pressure

  15. Laser cooling of a stored ion beam: A first step towards crystalline beams

    Energy Technology Data Exchange (ETDEWEB)

    Hangst, J.S.

    1992-09-01

    This report discusses: a brief introduction to storage rings; crystalline beams; laser cooling of ion beams; description of astrid-the experimental setup; first experiments with lithium 7 ion beam; experiments with erbium 166 ion beams; further experiments with lithium 7 ion beams; beam dynamics, laser cooling,and crystalline beams in astrid; possibilities for further study in astrid.

  16. Beam Instrument Development System

    Energy Technology Data Exchange (ETDEWEB)

    2016-01-08

    Beam Instrumentation Development System (BIDS) is a collection of common support libraries and modules developed during a series of Low-Level Radio Frequency (LLRF) control and timing/synchronization projects. BIDS includes a collection of Hardware Description Language (HDL) libraries and software libraries. The BIDS can be used for the development of any FPGA-based system, such as LLRF controllers. HDL code in this library is generic and supports common Digital Signal Processing (DSP) functions, FPGA-specific drivers (high-speed serial link wrappers, clock generation, etc.), ADC/DAC drivers, Ethernet MAC implementation, etc.

  17. Dynamic acoustic tractor beams

    Energy Technology Data Exchange (ETDEWEB)

    Mitri, F. G., E-mail: F.G.Mitri@ieee.org [Chevron, Area 52 Technology – ETC, Santa Fe, New Mexico 87508 (United States)

    2015-03-07

    Pulling a sphere and vibrating it around an equilibrium position by amplitude-modulation in the near-field of a single finite circular piston transducer is theoretically demonstrated. Conditions are found where a fluid hexane sphere (with arbitrary radius) chosen as an example, centered on the axis of progressive propagating waves and submerged in non-viscous water, experiences an attractive (steady) force pulling it towards the transducer, as well as an oscillatory force forcing it to vibrate back-and-forth. Numerical predictions for the dynamic force illustrate the theory and suggest an innovative method in designing dynamic acoustical tractor beams.

  18. Dynamic acoustic tractor beams

    Science.gov (United States)

    Mitri, F. G.

    2015-03-01

    Pulling a sphere and vibrating it around an equilibrium position by amplitude-modulation in the near-field of a single finite circular piston transducer is theoretically demonstrated. Conditions are found where a fluid hexane sphere (with arbitrary radius) chosen as an example, centered on the axis of progressive propagating waves and submerged in non-viscous water, experiences an attractive (steady) force pulling it towards the transducer, as well as an oscillatory force forcing it to vibrate back-and-forth. Numerical predictions for the dynamic force illustrate the theory and suggest an innovative method in designing dynamic acoustical tractor beams.

  19. Continuous Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1996-01-01

    This report deals with stress and stiffness estimates of continuous reinforced concrete beams with different stiffnesses for negative and positive moments e.g. corresponding to different reinforcement areas in top and bottom. Such conditions are often met in practice.The moment distribution...... at the limit state of serviceability is in some simple cases determined by setting up the statical and the compatibility conditions.With these moment distributions, the maximum deflection and the reinforcement stresses at the span middle and at a support are calculated.The results are compared with results...

  20. Injection Beam Loss and Beam Quality Checks for the LHC

    CERN Document Server

    Kain, Verena; Bartmann, Wolfgang; Bracco, Chiara; Drosdal, Lene; Holzer, Eva; Khasbulatov, Denis; Magnin, Nicolas; Meddahi, Malika; Nordt, Annika; Sapinski, Mariusz; Vogt, Mathias

    2010-01-01

    The quality of the injection into the LHC is monitored by a dedicated software system which acquires and analyses the pulse waveforms from the injection kickers, and measures key beam parameters and compares them with the nominal ones. The beam losses at injection are monitored on many critical devices in the injection regions, together with the longitudinal filling pattern and maximum trajectory offset on the first 100 turns. The paper describes the injection quality check system and the results from LHC beam commissioning, in particular the beam losses measured during injection at the various aperture limits. The results are extrapolated to full intensity and the consequences are discussed

  1. Estimation of the Processing Parameters in Electron Beam Thermal Treatments

    OpenAIRE

    Dulau, Mircea

    2014-01-01

    Electron beam have many special properties which make them particularly well suited for use in materials handling through melting, welding, surface treatment, etc., taking into account that this manufacturing is performed in vacuum. The use of electron beam for surface limited heat treatment of workpiece has brought about a noticeable extension of the beam technologies. Some theoretical aspects and simulation results are presented in this paper, considering a high power electron beam processi...

  2. Beam Position Monitoring at CLIC

    CERN Document Server

    Prochnow, J

    2003-01-01

    At the European Organisation for Nuclear Research CERN in Geneva, Switzerland the design of the Compact LInear Collider (CLIC) for high energy physics is studied. To achieve the envisaged high luminosity the quadrupole magnets and radio-frequency accelerating structures have to be actively aligned with micron precision and submicron resolution. This will be done using beam-based algorithms which rely on beam position information inside of quadrupoles and accelerating structures. After a general introduction to the CLIC study and the alignment algorithms, the concept of the interaction between beams and radio-frequency structures is given. In the next chapter beam measurements and simulations are described which were done to study the performance of cavity beam position monitors (BPM). A BPM design is presented which is compatible with the multi-bunch operation at CLIC and could be used to align the quadrupoles. The beam position inside the accelerating structures will be measured by using the structures thems...

  3. Controlling Beam Halo-Chaos

    Institute of Scientific and Technical Information of China (English)

    方锦清; 罗晓曙; 陈关荣; 翁甲强

    2001-01-01

    Beam halo-chaos is essentially a complex spatiotemporal chaotic motion in a periodic-focusing channel of a highpower linear proton accelerator. The controllability condition for beam halo-chaos is analysed qualitatively. A special nonlinear control method, i.e. the wavelet-based function feedback, is proposed for controlling beam halochaos. Particle-in-cell simulations are used to explore the nature of halo-chaos formation, which has shown that the beam hMo-chaos is suppressed effectively after using nonlinear control for the proton beam with an initial full Gaussian distribution. The halo intensity factor Hav is reduced from 14%o to zero, and the other statistical physical quantities of beam halo-chaos are more than doubly reduced. The potential applications of such nonlinear control in experiments are briefly pointed out.

  4. Self accelerating electron Airy beams

    CERN Document Server

    Voloch-Bloch, Noa; Lilach, Yigal; Gover, Avraham; Arie, Ady

    2013-01-01

    We report the first experimental generation and observation of Airy beams of free electrons. The electron Airy beams are generated by diffraction of electrons through a nanoscale hologram, that imprints a cubic phase modulation on the beams' transverse plane. We observed the spatial evolution dynamics of an arc-shaped, self accelerating and shape preserving electron Airy beams. We directly observed the ability of electrons to self-heal, restoring their original shape after passing an obstacle. This electromagnetic method opens up new avenues for steering electrons, like their photonic counterparts, since their wave packets can be imprinted with arbitrary shapes or trajectories. Furthermore, these beams can be easily manipulated using magnetic or electric potentials. It is also possible to efficiently self mix narrow beams having opposite signs of acceleration, hence obtaining a new type of electron interferometer.

  5. Collimation with hollow electron beams

    CERN Document Server

    Stancari, G; Annala, G; Kuznetsov, G; Shiltsev, V; Still, D A; Vorobiev, L G

    2011-01-01

    A novel concept of controlled halo removal for intense high-energy beams in storage rings and colliders is presented. It is based on the interaction of the circulating beam with a 5-keV, magnetically confined, pulsed hollow electron beam in a 2-m-long section of the ring. The electrons enclose the circulating beam, kicking halo particles transversely and leaving the beam core unperturbed. By acting as a tunable diffusion enhancer and not as a hard aperture limitation, the hollow electron beam collimator extends conventional collimation systems beyond the intensity limits imposed by tolerable losses. The concept was tested experimentally at the Fermilab Tevatron proton-antiproton collider. The first results on the collimation of 980-GeV antiprotons are presented.

  6. 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.

  7. 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.

  8. Beam simulation studies of ECR beam extraction and low energy beam transport for FRIB

    International Nuclear Information System (INIS)

    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

  9. Heating and Melting Model Induced by LaserBeam in Solid Material

    Directory of Open Access Journals (Sweden)

    Faiz F. Mustafa

    2008-01-01

    Full Text Available An analytical method and a two-dimensional finite element model for treating the problem of laser heating and melting has been applied to aluminum 2519T87and stainless steel 304. The time needed to melt and vaporize and the effects of laser power density on the melt depth for two metals are also obtained. In addition, the depth profile and time evolution of the temperature before melting and after melting are given, in which a discontinuity in the temperature gradient is obviously observed due to the latent heat of fusion and the increment in thermal conductivity in solid phase. The analytical results that induced by laser irradiation is in good agreement with numerical results.

  10. Multi-megajoule heating of large tokamaks with high energy heavy ion beams

    International Nuclear Information System (INIS)

    The fast neutral injection heating and RF heating for tokamak like plasmas are now well established. We consider in this paper the use of high energy (approximately 1 GeV) heavy ions (Xe132) to reach ignition in JET or INTOR like tokamaks. The main advantages of such a method will be outlined. The capture and the confinement of heavy ions have been analysed in a particular case and with the described RF linac it seems possible to inject in the order of 50 MJ in 1 sec with a modest increase of the effective charge Zsub(eff)<1.05 in a JET-like plasma for a particle life time of 1 sec and then the additional radiated power should be maintained at a relatively low level in comparison to the injected power

  11. Beam emittance measurements at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, Manfred; Eddy, Nathan; Hu, Martin; Scarpine, Victor; Syphers, Mike; Tassotto, Gianni; Thurman-Keup, Randy; Yang, Ming-Jen; Zagel, James; /Fermilab

    2008-01-01

    We give short overview of various beam emittance measurement methods, currently applied at different machine locations for the Run II collider physics program at Fermilab. All these methods are based on beam profile measurements, and we give some examples of the related instrumentation techniques. At the end we introduce a multi-megawatt proton source project, currently under investigation at Fermilab, with respect to the beam instrumentation challenges.

  12. Atomic laser-beam finder.

    Science.gov (United States)

    Viering, Kirsten; Medellin, David; Mo, Jianyong; Raizen, Mark G

    2012-11-01

    We report on an experimental method to align a laser beam to a cloud of atoms trapped in a magneto-optical trap (MOT). We show how balanced lock-in detection leads to a very sensitive method to align the laser beam to the atoms in the plane perpendicular to the propagation direction. This provides a very reliable and fast way of aligning laser beams to atoms trapped in a MOT.

  13. Harmonic vibrations of multispan beams

    DEFF Research Database (Denmark)

    Dyrbye, Claes

    1996-01-01

    Free and forced harmonic vibrations of multispan beams are determined by a method which implies 1 equation regardless of the configuration. The necessary formulas are given in the paper. For beams with simple supports and the same length of all (n) spans, there is a rather big difference between...... the n´th and the (n+1)´th eigenfrequency. The reason for this phenomenon is explained.Keywords: Vibrations, Eigenfrequencies, Beams....

  14. Effect of post-weld heat treatment on the mechanical properties of electron beam welded joints for CLAM steel

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qingsheng, E-mail: chunjing.li@fds.org.cn; Zheng, Shuhui; Liu, Shaojun; Li, Chunjing; Huang, Qunying

    2013-11-15

    In this paper the microstructure and mechanical properties of electron beam weld (EBW) joints for China low activation martensitic (CLAM) steel, which underwent a series of different post weld heat treatments (PWHTs) were studied. The aim of the study was to identify suitable PWHTs that give a good balance between strength and toughness of the EBW joints. The microstructural analyses were performed by means of optical microscope (OM) and scanning electron microscope (SEM). The mechanical properties were determined via tensile tests and Charpy impact tests. The results showed that the tensile strength of the as-weld joint (i.e. without any PWHT) were close to that of the base metal, but the impact toughness was only 13% of that of the base metal due to the existence of a delta-ferrite microstructure. To achieve a significant improvement in toughness a PWHT needs to be performed. If a one-step PWHT is applied tempering at 760 °C for 2 h gives EBW joints with high strength at a still acceptable toughness level. If a two-step PWHT is applied, a process involving quenching at 980 °C for 0.5 h followed by tempering at 740 °C or 760 °C for 2 h gives EBW joints with high strength and toughness properties. Whenever possible a two-step PWHT should be applied in favor of a one-step process, because of higher resulting strength and toughness properties.

  15. Effect of post-weld heat treatment on the mechanical properties of electron beam welded joints for CLAM steel

    Science.gov (United States)

    Wu, Qingsheng; Zheng, Shuhui; Liu, Shaojun; Li, Chunjing; Huang, Qunying

    2013-11-01

    In this paper the microstructure and mechanical properties of electron beam weld (EBW) joints for China low activation martensitic (CLAM) steel, which underwent a series of different post weld heat treatments (PWHTs) were studied. The aim of the study was to identify suitable PWHTs that give a good balance between strength and toughness of the EBW joints. The microstructural analyses were performed by means of optical microscope (OM) and scanning electron microscope (SEM). The mechanical properties were determined via tensile tests and Charpy impact tests. The results showed that the tensile strength of the as-weld joint (i.e. without any PWHT) were close to that of the base metal, but the impact toughness was only 13% of that of the base metal due to the existence of a delta-ferrite microstructure. To achieve a significant improvement in toughness a PWHT needs to be performed. If a one-step PWHT is applied tempering at 760 °C for 2 h gives EBW joints with high strength at a still acceptable toughness level. If a two-step PWHT is applied, a process involving quenching at 980 °C for 0.5 h followed by tempering at 740 °C or 760 °C for 2 h gives EBW joints with high strength and toughness properties. Whenever possible a two-step PWHT should be applied in favor of a one-step process, because of higher resulting strength and toughness properties.

  16. Bleaching absorption fronts and beam propagation in laser-heated solenoids

    International Nuclear Information System (INIS)

    It is shown that the propagation velocity of bleaching laser-driven heating waves in the supersonic mode is governed by the requirement that the bleached plasma maintains an optical thickness of unity. It is proposed that in the case where the bleached plasma is confined by very large magnetic fields, the diameter of the plasma column may self-regulate so that the bleaching wave propagates at the Alfven velocity

  17. Ion beam assisted film growth

    CERN Document Server

    Itoh, T

    2012-01-01

    This volume provides up to date information on the experimental, theoretical and technological aspects of film growth assisted by ion beams.Ion beam assisted film growth is one of the most effective techniques in aiding the growth of high-quality thin solid films in a controlled way. Moreover, ion beams play a dominant role in the reduction of the growth temperature of thin films of high melting point materials. In this way, ion beams make a considerable and complex contribution to film growth. The volume will be essential reading for scientists, engineers and students working in thi

  18. Compact electron beam focusing column

    Energy Technology Data Exchange (ETDEWEB)

    Persaud, Arun; Leung, Ka-Ngo; Reijonen, Jani

    2001-07-13

    A novel design for an electron beam focusing column has been developed at LBNL. The design is based on a low-energy spread multicusp plasma source which is used as a cathode for electron beam production. The focusing column is 10 mm in length. The electron beam is focused by means of electrostatic fields. The column is designed for a maximum voltage of 50 kV. Simulations of the electron trajectories have been performed by using the 2-D simulation code IGUN and EGUN. The electron temperature has also been incorporated into the simulations. The electron beam simulations, column design and fabrication will be discussed in this presentation.

  19. Applications of power beaming from space-based nuclear power stations. [Laser beaming to airplanes; microwave beaming to ground

    Energy Technology Data Exchange (ETDEWEB)

    Powell, J.R.; Botts, T.E.; Hertzberg, A.

    1981-01-01

    Power beaming from space-based reactor systems is examined using an advanced compact, lightweight Rotating Bed Reactor (RBR). Closed Brayton power conversion efficiencies in the range of 30 to 40% can be achieved with turbines, with reactor exit temperatures on the order of 2000/sup 0/K and a liquid drop radiator to reject heat at temperatures of approx. 500/sup 0/K. Higher RBR coolant temperatures (up to approx. 3000/sup 0/K) are possible, but gains in power conversion efficiency are minimal, due to lower expander efficiency (e.g., a MHD generator). Two power beaming applications are examined - laser beaming to airplanes and microwave beaming to fixed ground receivers. Use of the RBR greatly reduces system weight and cost, as compared to solar power sources. Payback times are a few years at present prices for power and airplane fuel.

  20. Long range beam-beam interaction and the effect on the beam and luminosity lifetimes

    CERN Document Server

    Crouch, Matthew; Barranco Garcia, Javier; Banfi, Danilo; Buffat, Xavier; Tambasco, Claudia; Alexahin, Yuri; Bruce, Roderik; Giachino, Rossano; Pojer, Mirko; Salvachua Ferrando, Belen Maria; Solfaroli Camillocci, Matteo; Trad, Georges; CERN. Geneva. ATS Department

    2016-01-01

    Identifying the minimum crossing angle achievable in the LHC is a key parameter to identify the collider luminosity reach. In this note, we summarise the observations collected during a dedicated experiment performed in 2015, where the strength of the long range beam-beam interaction is varied by reducing the crossing angle at IP1 and IP5. The crossing angle and the impact of the long range beam-beam interaction is analysed with respect to the beam and luminosity lifetimes. The effect of reducing Landau octupoles initially operating at 476 [A] and high chromaticity values (15 units) are also shown. The minimum crossing angle achievable with collisions is identified, together with the impact on beam and luminosity lifetimes

  1. Accelerators, Beams And Physical Review Special Topics - Accelerators And Beams

    Energy Technology Data Exchange (ETDEWEB)

    Siemann, R.H.; /SLAC

    2011-10-24

    Accelerator science and technology have evolved as accelerators became larger and important to a broad range of science. Physical Review Special Topics - Accelerators and Beams was established to serve the accelerator community as a timely, widely circulated, international journal covering the full breadth of accelerators and beams. The history of the journal and the innovations associated with it are reviewed.

  2. Single Gradientless Light Beam Drags Particles as Tractor Beams

    DEFF Research Database (Denmark)

    Novitsky, Andrey; Qiu, Cheng-Wei; Wang, Haifeng

    2011-01-01

    Usually a light beam pushes a particle when the photons act upon it. We investigate the optical forces by nonparaxial gradientless beams and find that the forces can drag suitable particles all the way towards the light source. The major criterion of realizing the backward dragging force is the s...

  3. LHC beam-beam compensation using wires and electron lenses

    CERN Document Server

    Dorda, U; Shiltsev, V; Zimmermann, F

    2007-01-01

    We present weak-strong simulation results for a possible application of current-carrying wires and electron lenses to compensate the LHC long-range and head-on beambeam interaction, respectively, for nominal and PACMAN bunches. We show that these measures have the potential to considerably increase the beam-beam limit, allowing for a corresponding increase in peak luminosity.

  4. Effects of He-Ne laser beam on mechanical, heat, chemical and superficial wounds

    International Nuclear Information System (INIS)

    This study summarizes the effects of low-doses of He-Ne laser radiation (λ = 6328 A), on healing of four types of wounds, including mechanical, heat, chemical and superficial wounds. The results revealed that variations between complete wound-closure in irradiated samples and that of control groups were statistically significant. Moreover, the results suggest that the stimulative action of laser is an accumulative phenomenon, that affects factors involved in the course of wound healing. The results also indicate that the skin epithelium is a highly responsive tissue towards this sort of radiation, which suggests that the stimulative action of He-Ne laser could be assayed easily by using such tissues as a test target. (author). 11 refs, 2 tabs

  5. Single-beam collective phenomena transverse I Coasting beams

    CERN Document Server

    Zotter, Bruno W

    1977-01-01

    If a charged particle beam is locally displaced or kicked (e.g. by noise), it will start to oscillate around an equilibrium orbit ('betatron oscillations') due to the external focusing fields of an accelerator or storage ring. These oscillations will excite electromagnetic fields which are modified by the presence of the vacuum chamber walls or other material boundaries in the neighbourhood of the beam. The electromagnetic fields react back on the oscillating beam. If there is an out of phase component of the forces, such as caused by the finite resistivity of the walls, the original oscillations may be reinforced. Their amplitude will then grow exponentially, i.e. the beam is unstable. Linear theory is only concerned with the conditions for the onset of the instability, i.e. the thresholds and initial growth rates, or with the means to stabilize the beam, e.g. by Landau damping or feedback.

  6. Experimental study of proton beam halo in mismatched beams

    International Nuclear Information System (INIS)

    We report measurements of transverse beam-halo formation in mismatched proton beams in a 52-quadrupole FODO-transport channel following the 6.7 MeV RFQ at the Low-Energy Demonstration Accelerator (LEDA) at Los Alamos. Beam profiles in both transverse planes were measured using a new diagnostic device that consists of a movable carbon filament for measurement of the beam core, and scraper plates for measurement of the outer part of the distributions. The initial results indicate a surprisingly strong growth rate of the rms emittance even for the modest space-charge tune depressions of the experiment. Our results are consistent with the complete transfer of free energy of the mismatched beams into emittance growth within 10 envelope oscillations for both the breathing and the quadrupole modes.

  7. Neutron beam tomography software

    International Nuclear Information System (INIS)

    When a sample is traversed by a neutron beam, inhomogeneities in the sample will cause deflections, and the deflections will permit conclusions to be drawn concerning the location and size of the inhomogeneities. The associated computation is similar to problems in tomography, analogous to X-ray tomography though significantly different in detail. We do not have any point-sample information, but only mean values over short line segments. Since each mean value is derived from a separate neutron counter, the quantity of available data has to be modest; also, since each datum is an integral, its geometric precision is inferior to that of X-ray data. Our software is designed to cope with these difficulties. (orig.)

  8. Neutron beam measurement dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Amaro, C.R. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1995-11-01

    This report describes animal dosimetry studies and phantom measurements. During 1994, 12 dogs were irradiated at BMRR as part of a 4 fraction dose tolerance study. The animals were first infused with BSH and irradiated daily for 4 consecutive days. BNL irradiated 2 beagles as part of their dose tolerance study using BPA fructose. In addition, a dog at WSU was irradiated at BMRR after an infusion of BPA fructose. During 1994, the INEL BNCT dosimetry team measured neutron flux and gamma dose profiles in two phantoms exposed to the epithermal neutron beam at the BMRR. These measurements were performed as a preparatory step to the commencement of human clinical trials in progress at the BMRR.

  9. Polarized targets and beams

    International Nuclear Information System (INIS)

    First the experimental situation of the single-pion photoproduction and the photodisintegration of the deuteron is briefly discussed. Then a description of the Bonn polarization facilities is given. The point of main effort is put on the polarized target which plays a vital role in the program. A facility for photon induced double polarization experiments at ELSA will be presented in section 4. Properties of a tensor polarized deuteron target are discussed in section 5. The development in the field of polarized targets, especially on new target materials, enables a new generation of polarized target experiments with (polarized) electrons. Some comments on the use of a polarized target in combination with electron beams will be discussed in section 6. Electron deuteron scattering from a tensor polarized deuteron target is considered and compared with other experimental possibilities. (orig./HSI)

  10. In Process Beam Monitoring

    Science.gov (United States)

    Steen, W. M.; Weerasinghe, V. M.

    1986-11-01

    The industrial future of lasers in material processing lies in the combination of the laser with automatic machinery. One possible form of such a combination is an intelligent workstation which monitors the process as it occurs and adjusts itself accordingly, either by self teaching or by comparison to a process data bank or algorithm. In order to achieve this attractive goal in-process signals are required. Two devices are described in this paper. One is the Laser Beam Analyser which is now maturing into a second generation with computerised output. The other is the Acoustic Mirror, a totally novel analytic technique, not yet fully understood, but which nevertheless can act as a very effective process monitor.

  11. Design and Analysis Methodologies for Inflated Beams

    NARCIS (Netherlands)

    Veldman, S.L.

    2005-01-01

    The central theme of the thesis is bending behaviour of inflated beams. Three different types of beams have been analysed for the bending load case: a straight cylindrical beam made of anisotropic foil material, a conical beam made of an isotropic foil material, and a carbon fibre braided beam. The

  12. Molecular-beam scattering

    Science.gov (United States)

    Vernon, M. F.

    1983-07-01

    The molecular-beam technique has been used in three different experimental arrangements to study a wide range of inter-atomic and molecular forces. Chapter 1 reports results of a low-energy (0.2 kcal/mole) elastic-scattering study of the He-Ar pair potential. The purpose of the study was to accurately characterize the shape of the potential in the well region, by scattering slow He atoms produced by expanding a mixture of He in N2 from a cooled nozzle. Chapter 2 contains measurements of the vibrational predissociation spectra and product translational energy for clusters of water, benzene, and ammonia. The experiments show that most of the product energy remains in the internal molecular motions. Chapter 3 presents measurements of the reaction Na + HC1 (FEMALE) NAC1 + H at collision energies of 5.38 and 19.4 kcal/mole. This is the first study to resolve both scattering angle and velocity for the reaction of a short lived (16 nsec) electronic excited state. Descriptions are given of computer programs written to analyze molecular-beam expansions to extract information characterizing their velocity distributions, and to calculate accurate laboratory elastic-scattering differential cross sections accounting for the finite apparatus resolution. Experimental results which attempted to determine the efficiency of optically pumping the Li(2(2)P/sub 3/2/) and Na(3(2)P/sub 3/2) excited states are given. A simple three-level model for predicting the steady-state fraction of atoms in the excited state is included.

  13. Molecular-beam scattering

    Energy Technology Data Exchange (ETDEWEB)

    Vernon, M.F.

    1983-07-01

    The molecular-beam technique has been used in three different experimental arrangements to study a wide range of inter-atomic and molecular forces. Chapter 1 reports results of a low-energy (0.2 kcal/mole) elastic-scattering study of the He-Ar pair potential. The purpose of the study was to accurately characterize the shape of the potential in the well region, by scattering slow He atoms produced by expanding a mixture of He in N/sub 2/ from a cooled nozzle. Chapter 2 contains measurements of the vibrational predissociation spectra and product translational energy for clusters of water, benzene, and ammonia. The experiments show that most of the product energy remains in the internal molecular motions. Chapter 3 presents measurements of the reaction Na + HCl ..-->.. NaCl + H at collision energies of 5.38 and 19.4 kcal/mole. This is the first study to resolve both scattering angle and velocity for the reaction of a short lived (16 nsec) electronic excited state. Descriptions are given of computer programs written to analyze molecular-beam expansions to extract information characterizing their velocity distributions, and to calculate accurate laboratory elastic-scattering differential cross sections accounting for the finite apparatus resolution. Experimental results which attempted to determine the efficiency of optically pumping the Li(2/sup 2/P/sub 3/2/) and Na(3/sup 2/P/sub 3/2/) excited states are given. A simple three-level model for predicting the steady-state fraction of atoms in the excited state is included.

  14. Molecular-beam scattering

    International Nuclear Information System (INIS)

    The molecular-beam technique has been used in three different experimental arrangements to study a wide range of inter-atomic and molecular forces. Chapter 1 reports results of a low-energy (0.2 kcal/mole) elastic-scattering study of the He-Ar pair potential. The purpose of the study was to accurately characterize the shape of the potential in the well region, by scattering slow He atoms produced by expanding a mixture of He in N2 from a cooled nozzle. Chapter 2 contains measurements of the vibrational predissociation spectra and product translational energy for clusters of water, benzene, and ammonia. The experiments show that most of the product energy remains in the internal molecular motions. Chapter 3 presents measurements of the reaction Na + HCl → NaCl + H at collision energies of 5.38 and 19.4 kcal/mole. This is the first study to resolve both scattering angle and velocity for the reaction of a short lived (16 nsec) electronic excited state. Descriptions are given of computer programs written to analyze molecular-beam expansions to extract information characterizing their velocity distributions, and to calculate accurate laboratory elastic-scattering differential cross sections accounting for the finite apparatus resolution. Experimental results which attempted to determine the efficiency of optically pumping the Li(22P/sub 3/2/) and Na(32P/sub 3/2/) excited states are given. A simple three-level model for predicting the steady-state fraction of atoms in the excited state is included

  15. Measurements of aperture and beam lifetime using movable beam scrapers in Indus-2 electron storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pradeep; Ghodke, A. D.; Karnewar, A. K.; Holikatti, A. C.; Yadav, S.; Puntambekar, T. A.; Singh, G. [Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Singh, P. [Bhabha Atomic Research Centre, Mumbai (India)

    2013-12-15

    In this paper, the measurements of vertical and horizontal aperture which are available for stable beam motion in Indus-2 at beam energy 2.5 GeV using movable beam scrapers are presented. These beam scrapers are installed in one of the long straight sections in the ring. With the movement of beam scrapers towards the beam centre, the beam lifetime is measured. The beam lifetime data obtained from the movement of vertical and horizontal beam scrapers are analyzed. The contribution of beam loss due to beam-gas scattering (vacuum lifetime) and electron-electron scattering within a beam bunch (Touschek lifetime) is separated from the measured beam lifetime at different positions of the beam scrapers. Vertical and horizontal beam sizes at scrapers location are estimated from the scraper movement towards the beam centre in quantum lifetime limit and their values closely agree with measured value obtained using X-ray diagnostic beamline.

  16. Measurements of aperture and beam lifetime using movable beam scrapers in Indus-2 electron storage ring.

    Science.gov (United States)

    Kumar, Pradeep; Ghodke, A D; Karnewar, A K; Holikatti, A C; Yadav, S; Puntambekar, T A; Singh, G; Singh, P

    2013-12-01

    In this paper, the measurements of vertical and horizontal aperture which are available for stable beam motion in Indus-2 at beam energy 2.5 GeV using movable beam scrapers are presented. These beam scrapers are installed in one of the long straight sections in the ring. With the movement of beam scrapers towards the beam centre, the beam lifetime is measured. The beam lifetime data obtained from the movement of vertical and horizontal beam scrapers are analyzed. The contribution of beam loss due to beam-gas scattering (vacuum lifetime) and electron-electron scattering within a beam bunch (Touschek lifetime) is separated from the measured beam lifetime at different positions of the beam scrapers. Vertical and horizontal beam sizes at scrapers location are estimated from the scraper movement towards the beam centre in quantum lifetime limit and their values closely agree with measured value obtained using X-ray diagnostic beamline.

  17. Space charge dominated beam transport

    International Nuclear Information System (INIS)

    We consider beam transport systems where space charge forces are comparable in strength with the external focusing force. Space charge then plays an important role for beam transmission and emittance growth. We use the envelope model for matching and the generalized field energy equations to study emittance growth. Analytic results are compared with numerical simulation. (orig.)

  18. BOUNDARY STABILIZATION OF TIMOSHENKO BEAM

    Institute of Scientific and Technical Information of China (English)

    YAN Qingxu

    2000-01-01

    In this paper, the stabilization problem of Timoshenko beam by some nonlinear boundary feedback controls is considered. By virtue of nonlinear semigroup theory and energy-perturbed method, it is shown that the vibration of the beam under the proposed control action decays exponentially or in negative power of time t as t → ∞.

  19. Portal dosimetry in wedged beams

    NARCIS (Netherlands)

    Spreeuw, H.; Rozendaal, R.; Camargo, P.; Mans, A.; Wendling, M.; Olaciregui-Ruiz, I.; Sonke, J.J.; Herk, M. van; Mijnheer, B.

    2015-01-01

    Portal dosimetry using electronic portal imaging devices (EPIDs) is often applied to verify high-energy photon beam treatments. Due to the change in photon energy spectrum, the resulting dose values are, however, not very accurate in the case of wedged beams if the pixel-to-dose conversion for the s

  20. Hybrid beams in the LHC

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    The first proton-ion beams were successfully circulated in the LHC a couple of weeks ago. Everything went so smoothly that the LHC teams had planned the first p-Pb collisions for Wednesday, 16 November. Unfortunately, a last-minute problem with a component of the PS required for proton acceleration prevented the LHC teams from making these new collisions. However, the way is open for a possible physics run with proton-lead collisions in 2012.   Members of the LHC team photographed when the first hybrid beams got to full energy. The proton and lead beams are visible on the leftmost screen up on the wall (click to enlarge the photo). The technical challenge of making different beams circulate in the LHC is by no means trivial. Even if the machine is the same, there are a number of differences when it is operated with beams of protons, beams of lead or beams of proton and lead. Provided that the beams are equal, irrespective of whether they consist of protons or lead nuclei, they revolve at the...

  1. Radioactive beams and their applications

    International Nuclear Information System (INIS)

    The proceedings contain lectures and contributed papers submitted to the second INR (Kiev's) International School on Nuclear Physics (Kiev, June 25 -July 2, 1991). The following sections were included in the Proceedings: Radioactive Beam Facilities, Application of Radioactive Beams in the Investigations of Nuclear Reactions, Exotic Nuclei and Clusters, Polarization Phenomena, Astrophysics and Others

  2. Beam dynamics for induction accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Edward P., E-mail: eplee@lbl.gov

    2014-01-01

    An induction linac uses pulsed power that is applied directly, without any intervening resonant cavities, to accelerate a charged particle pulse. This approach can accommodate a large multiple-beam focusing lattice capable of transporting a large total beam current with a long pulse duration, which may be compressed while accelerating as well as afterward. The mean accelerating gradient is relatively low (less than about 1.5 MV/m), but the potential efficiency of energy transfer can be large up to about 50%. A multiple-beam induction linac is therefore a natural candidate accelerator for a heavy ion fusion (HIF) driver. However, the accelerated beams must meet stringent requirements on occupied phase space volume in order to be focused accurately and with small radius onto the fusion target. Dynamical considerations in the beam injector and linac, as well as in the final compression, final focus, and the fusion chamber, determine the quality of the driver beams as they approach the target. Requirements and tolerances derived from beam dynamics strongly influence the linac configuration and component design. After a summary of dynamical considerations, two major topics are addressed here: transportable current limits, which determine the choice of focal system for the linac, and longitudinal control of the beams, which are potentially destabilized by their interaction with the pulsed power system.

  3. Beam tests of phosphorescent screens

    International Nuclear Information System (INIS)

    Twelve phosphorescent screens were beam tested for linearity, uniformity, low radiation damage and a suitable emitted wavelength for use with television cameras. One screen was chosen for the construction of several intercepting profile monitors which were used during the SLC Ten Sector Tests to measure the emittance and wakefield effects of a damped electron beam

  4. An rf electron beam buncher

    International Nuclear Information System (INIS)

    A method is described for producing density modulations on an intense relativistic electron beam by the use of rf fields in a betatron configuration. In concept, a device embodying this method should be capable of producing short (1-10 ns) electron bunches from a long (10-100 ns) beam, and is expected to be relatively compact and to operate efficiently on low power and energy. The method requires that the azimuthal phase velocity of the rf wave equal the electron beam velocity. Depending on phase relative to the rf wave, electrons in the beam gain or lose energy and form bunches by the negative mass effect. The dynamics of the electrons in the combined rf wave and betatron field have been analyzed. An example of an rf electron beam buncher is given

  5. Beta Beams Implementation at CERN

    CERN Document Server

    Hansen, Christian

    2011-01-01

    Beta Beam,the concept of generating a pure and intense (anti) neutrino beam by letting accelerated radioactive ions beta decay in a storage ring, called Decay Ring (DR), is the base of one of the proposed next generation neutrino oscillation facilities, necessary for a complete study of the neutrino oscillation parameter space. Sensitivities of the unknown neutrino oscillation parameters depend on the Decay Ring's ion intensity and of it's duty factor (the filled ratio of the ring). Therefore efficient ion production, stripping, bunching, acceleration and storing are crucial sub-projects under study and development within the Beta Beam collaboration. Specifically the feasibility of these tasks as parts of a Beta Beam implementation at CERN will be discussed in this report. The positive impact of the large {\\theta}13 indications from T2K on the Beta Beam performance will also be discussed.

  6. FXR fast beam imaging diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Ferriera, T; Gilliam, R; Ong, M; Wargo, P; Zentler, J

    1999-06-01

    The Lawrence Livermore National Laboratory Flash X-ray (FXR) machine is being upgraded to produce two pulses. A very fast imaging system has been developed to characterize the electron beam diameter and shape. The system consists of a kapton target insertion mechanism and a framing camera. It has a fast gated imaging tube (500 ps) and CCD subsystem to capture and send the image to the control room. The beam diameter data provides insight on mechanisms that effect the x-ray spot size. These colorful beam measurements will be compared with our other diagnostics to form a more complete picture of beam behavior. A demonstration will be described where the image data was used to design a collimator to improve x-ray beam performance.

  7. Autoacceleration of a modulated beam

    Energy Technology Data Exchange (ETDEWEB)

    Boiko, V.A.; Borodulin, A.I.; Voronkov, R.M.; Voskresenskii, G.V.; Galkin, V.S.; Dobrokhotov, V.V.; Kurdyumov, V.N.; Mamaev, G.L.; Simonov, K.G.

    1982-11-01

    The interaction of a density-modulated electron beam with a passive resonator is considered. The modulation frequency is equal to the resonant frequency of the resonator, and the beam parameters at the resonator outlet are studied as functions of the percentage of modulation. Calculations reveal that the maximum attainable energy at the outlet is approximately three times greater than the energy of the particles at the inlet. Experimental measurements of the beam parameters are reported. At the outlet of the passive resonator a beam of accelerated electrons was produced with current approx.100 A and energy >500 keV; the current in the initial beam was 250 A and the electron energy was 250 keV.

  8. NETWORK CODING BY BEAM FORMING

    DEFF Research Database (Denmark)

    2013-01-01

    Network coding by beam forming in networks, for example, in single frequency networks, can provide aid in increasing spectral efficiency. When network coding by beam forming and user cooperation are combined, spectral efficiency gains may be achieved. According to certain embodiments, a method...... includes operating a user equipment of a plurality of user equipment in a network comprising a plurality of access points. The method also includes the user equipment forming a beam. The method further receives processing received signals from at least one of the plurality of access points at the user...... equipment. The forming the beam is configured to let different user equipment of the plurality of user equipment to receive different signals from the plurality of access points to achieve diversity by using different beams amongst the plurality of user equipment. The method additionally includes...

  9. Cold and Slow Molecular Beam

    CERN Document Server

    Lu, Hsin-I; Wright, Matthew J; Patterson, Dave; Doyle, John M

    2011-01-01

    Employing a two-stage cryogenic buffer gas cell, we produce a cold, hydrodynamically extracted beam of calcium monohydride molecules with a near effusive velocity distribution. Beam dynamics, thermalization and slowing are studied using laser spectroscopy. The key to this hybrid, effusive-like beam source is a "slowing cell" placed immediately after a hydrodynamic, cryogenic source [Patterson et al., J. Chem. Phys., 2007, 126, 154307]. The resulting CaH beams are created in two regimes. One modestly boosted beam has a forward velocity of vf = 65 m/s, a narrow velocity spread, and a flux of 10^9 molecules per pulse. The other has the slowest forward velocity of vf = 40 m/s, a longitudinal temperature of 3.6 K, and a flux of 5x10^8 molecules per pulse.

  10. Toward automated beam optics control

    International Nuclear Information System (INIS)

    We have begun a program aiming toward automatic control of charged-particle beam optics using artificial intelligence programming techniques. In developing our prototype, we are working with LISP machines and the KEE expert system shell. Our first goal was to develop a ''mouseable'' representation of a typical beam line. This responds actively to changes entered from the mouse or keyboard, giving an updated display of the beam line itself, its optical properties, and the instrumentation and control devices as seen by the operater. We have incorporated TRANSPORT, written in Fortran but running as a callable procedure in the LISP environment, for simulation of the beam-line optics. This paper describes the experience gained in meeting our first goal and discusses plans to extend the work so that it is usable, in realtime, on an operating beam line. 11 refs

  11. Self-focusing and defocusing of Gaussian laser beams in collisional underdense magnetized plasmas with considering the nonlinear ohmic heating and ponderomotive force effects

    Energy Technology Data Exchange (ETDEWEB)

    Ettehadi Abari, Mehdi; Sedaghat, Mahsa; Shokri, Babak, E-mail: b-shokri@sbu.ac.ir [Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, G.C., 19839 Evin, Tehran (Iran, Islamic Republic of)

    2015-10-15

    The propagation characteristics of a Gaussian laser beam in collisional magnetized plasma are investigated by considering the ponderomotive and ohmic heating nonlinearities. Here, by taking into account the effect of the external magnetic field, the second order differential equation of the dimensionless beam width parameter is solved numerically. Furthermore, the nonlinear dielectric permittivity of the mentioned plasma medium in the paraxial approximation and its dependence on the propagation characteristics of the Gaussian laser pulse is obtained, and its variation in terms of the dimensionless plasma length is analyzed at different initial normalized plasma and cyclotron frequencies. The results show that the dimensionless beam width parameter is strongly affected by the initial plasma frequency, magnetic strength, and laser pulse intensity. Furthermore, it is found that there exists a certain intensity value below which the laser pulse tends to self focus, while the beam diverges above of this value. In addition, the results confirm that, by increasing the plasma and cyclotron frequencies (plasma density and magnetic strength), the self-focusing effect can occur intensively.

  12. Beam shaping for cosmetic hair removal

    Science.gov (United States)

    Lizotte, Todd E.; Tuttle, Tracie

    2007-09-01

    Beam shaping has the potential to provide comfort to people who require or seek laser based cosmetic skin procedures. Of immediate interest is the procedure of aesthetic hair removal. Hair removal is performed using a variety of wavelengths from 480 to 1200 nm by means of filtered Xenon flash lamps (pulsed light) or 810 nm diode lasers. These wavelengths are considered the most efficient means available for hair removal applications, but current systems use simple reflector designs and plane filter windows to direct the light to the surface being exposed. Laser hair removal is achieved when these wavelengths at sufficient energy levels are applied to the epidermis. The laser energy is absorbed by the melanin (pigment) in the hair and hair follicle which in turn is transformed into heat. This heat creates the coagulation process, which causes the removal of the hair and prevents growth of new hair [1]. This paper outlines a technique of beam shaping that can be applied to a non-contact based hair removal system. Several features of the beam shaping technique including beam uniformity and heat dispersion across its operational treatment area will be analyzed. A beam shaper design and its fundamental testing will be discussed in detail.

  13. Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability

    Directory of Open Access Journals (Sweden)

    Suzan Bsat

    2015-04-01

    Full Text Available Advanced additive manufacturing techniques such as electron beam melting (EBM, can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the current work, EBM porous Ti6Al4V alloy was exposed to an alkali acid heat (AlAcH treatment to bio-functionalize the surface of the porous structure. Various molar concentrations (3, 5, 10M and immersion times (6, 24 h of the alkali treatment were used to determine optimal parameters. The apatite forming ability of the samples was evaluated using simulated body fluid (SBF immersion testing. The micro-topography and surface chemistry of AlAcH treated samples were evaluated before and after SBF testing using scanning electron microscopy and energy dispersive X-ray spectroscopy. The AlAcH treatment successfully modified the topographical and chemical characteristics of EBM porous titanium surface creating nano-topographical features ranging from 200–300 nm in size with a titania layer ideal for apatite formation. After 1 and 3 week immersion in SBF, there was no Ca or P present on the surface of as manufactured porous titanium while both elements were present on all AlAcH treated samples except those exposed to 3M, 6 h alkali treatment. An increase in molar concentration and/or immersion time of alkali treatment resulted in an increase in the number of nano-topographical features per unit area as well as the amount of titania on the surface.

  14. Symmetric form-invariant dual Pearcey beams.

    Science.gov (United States)

    Ren, Zhijun; Fan, Changjiang; Shi, Yile; Chen, Bo

    2016-08-01

    We introduce another type of Pearcey beam, namely, dual Pearcey (DP) beams, based on the Pearcey function of catastrophe theory. DP beams are experimentally generated by applying Fresnel diffraction of bright elliptic rings. Form-invariant Bessel distribution beams can be regarded as a special case of DP beams. Subsequently, the basic propagation characteristics of DP beams are identified. DP beams are the result of the interference of two half DP beams instead of two classical Pearcey beams. Moreover, we also verified that half DP beams (including special-case parabolic-like beams) generated by half elliptical rings (circular rings) are a new member of the family of form-invariant beams. PMID:27505650

  15. On nonlinear development of beam instability

    International Nuclear Information System (INIS)

    Radiation-resonance interactions are taken into account in the problem of dynamics of an electron beam inb plasma. The beam characteristics to be taken into account are determined. Stabilization conditions for beam instability are established

  16. Modelling of Beam-Beam Effects in Multiscales

    CERN Document Server

    Fedorova, A N; Fedorova, Antonina N.; Zeitlin, Michael G.

    2001-01-01

    We present the applications of nonlinear local harmonic analysis methods to the modelling of beam-beam interaction. Our approach is based on methods provided the possibility to work with dynamical beam localization in phase space. The consideration of Fokker-Planck or Vlasov-Maxwell models is based on a number of anzatzes, which reduce initial problems to a number of dynamical systems (with constraints) and on variational-wavelet approach to polynomial/rational approximations for reduced nonlinear dynamics. We calculate contribution to full dynamics (partition function) from all underlying subscales via nonlinear eigenmodes decomposition.

  17. Development of fast beam-stop system using RF chopper

    International Nuclear Information System (INIS)

    To avoid heat damage and radioactivation by beam loss of the J-PARC accelerator, Machine Protection System (MPS) has been developed. Actually, high responsibility and high reliability have been achieved in J-PARC. Beam-stop method in addition to a way of RFQ OFF has been requested in order to avoid damage to the RFQ. Therefore, we have been developing a fast beam-stop system by using a RF chopper. The fast beam-stop system, including beam test, is described in this paper. (author)

  18. 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.

  19. Coherent instabilities of a relativistic bunched beam

    Energy Technology Data Exchange (ETDEWEB)

    Chao, A.W.

    1982-06-01

    A charge-particle beam contained in an accelerator vacuum chamber interacts electromagnetically with its environment to create a wake field. This field than acts back on the beam, perturbing the particle motion. If the beam intensity is high enough, this beam-environment interaction may lead to an instability and to subsequent beam loss. The beam and its environment form a dynamical system, and it is this system that will be studied. 84 references.

  20. The electron test accelerator beam injector

    International Nuclear Information System (INIS)

    A beam chopper and buncher system has been designed to improve the capture efficiency and reduce the beam spill in the Electron Test Accelerator. The buncher increases the dc beam capture from 30 to 70%. 100% beam transmission through the accelerator structures is obtained with the chopper. This report describes results of experimental tests with the beam injector. Results from computer modeling and from measurements with prototypes that have led to the design of the beam chopper and buncher system are discussed

  1. Experimental studies on beam-plasma interaction

    International Nuclear Information System (INIS)

    Beam-handling technology has reached now at such a level as to enable highly controlled experiments of beam-plasma interaction. Varieties of hypotheses and suppositions about the beam propagation and interaction in space plasma can be proved and often be corrected by examining the specific processes in laboratory plasma. The experiments performed in this way by the author are briefed: ion beam instability in unmagnetized plasma; ion beam instability perpendicular to magnetic field; and electron beam instability. (Mori, K.)

  2. Cryogenic Beam Screens for High-Energy Particle Accelerators

    CERN Document Server

    Baglin, V; Tavian, L; van Weelderen, R

    2013-01-01

    Applied superconductivity has become a key enabling technology for high-energy particle accelerators, thus making them large helium cryogenic systems operating at very low temperature. The circulation of high-intensity particle beams in these machines generates energy deposition in the first wall through different processes. For thermodynamic efficiency, it is advisable to intercept these beam-induced heat loads, which may be large in comparison with cryostat heat in-leaks, at higher temperature than that of the superconducting magnets of the accelerator, by means of beam screens located in the magnet apertures. Beam screens may also be used as part of the ultra-high vacuum system of the accelerator, by sheltering the gas molecules cryopumped on the beam pipe from impinging radiation and thus avoiding pressure runaway. Space being extremely tight in the magnet apertures, cooling of the long, slender beam screens also raises substantial problems in cryogenic heat transfer and fluid flow. We present sizing rule...

  3. Random sources for cusped beams.

    Science.gov (United States)

    Li, Jia; Wang, Fei; Korotkova, Olga

    2016-08-01

    We introduce two novel classes of partially coherent sources whose degrees of coherence are described by the rectangular Lorentz-correlated Schell-model (LSM) and rectangular fractional multi-Gaussian-correlated Schell-model (FMGSM) functions. Based on the generalized Collins formula, analytical expressions are derived for the spectral density distributions of these beams propagating through a stigmatic ABCD optical system. It is shown that beams belonging to both classes form the spectral density apex that is much higher and sharper than that generated by the Gaussian Schell-model (GSM) beam with a comparable coherence state. We experimentally generate these beams by using a nematic, transmissive spatial light modulator (SLM) that serves as a random phase screen controlled by a computer. The experimental data is consistent with theoretical predictions. Moreover, it is illustrated that the FMGSM beam generated in our experiments has a better focusing capacity than the GSM beam with the same coherence state. The applications that can potentially benefit from the use of novel beams range from material surface processing, to communications and sensing through random media. PMID:27505746

  4. Dark matter beams at LBNF

    CERN Document Server

    Coloma, Pilar; Frugiuele, Claudia; Harnik, Roni

    2015-01-01

    High-intensity neutrino beam facilities may produce a beam of light dark matter when protons strike the target. Searches for such a dark matter beam using its scattering in a nearby detector must overcome the large neutrino background. We characterize the spatial and energy distributions of the dark matter and neutrino beams, focusing on their differences to enhance the sensitivity to dark matter. We find that a dark matter beam produced by a $Z'$ boson in the GeV mass range is both broader and more energetic than the neutrino beam. The reach for dark matter is maximized for a detector sensitive to hard neutral-current scatterings, placed at a sizable angle off the neutrino beam axis. In the case of the Long-Baseline Neutrino Facility (LBNF), a detector placed at roughly 6 degrees off axis and at a distance of about 200 m from the target would be sensitive to $Z'$ couplings as low as 0.05. This search can proceed symbiotically with neutrino measurements. We also show that the MiniBooNE and MicroBooNE detector...

  5. Asymmetric Laguerre-Gaussian beams

    Science.gov (United States)

    Kovalev, A. A.; Kotlyar, V. V.; Porfirev, A. P.

    2016-06-01

    We introduce a family of asymmetric Laguerre-Gaussian (aLG) laser beams. The beams have been derived via a complex-valued shift of conventional LG beams in the Cartesian plane. While propagating in a uniform medium, the first bright ring of the aLG beam becomes less asymmetric and the energy is redistributed toward peripheral diffraction rings. The projection of the orbital angular momentum (OAM) onto the optical axis is calculated. The OAM is shown to grow quadratically with increasing asymmetry parameter of the aLG beam, which equals the ratio of the shift to the waist radius. Conditions for the OAM becoming equal to the topological charge have been derived. For aLG beams with zero radial index, we have deduced an expression to define the intensity maximum coordinates and shown the crescent-shaped intensity pattern to rotate during propagation. Results of the experimental generation and rotation of aLG beams agree well with theoretical predictions.

  6. Multi channel beam profile digitizer

    International Nuclear Information System (INIS)

    Beam of ions in an accelerator are focussed with the help of focussing magnets to achieve very narrow circular beam. To verify the beam profile along its length, Beam Profile Monitors (BPM) are installed at number of points. The signal generated from these units convey information about the shape and axial error of the beam. Presently BPM signals are monitored on oscilloscope. One oscilloscope is required per BPM channel to be monitored and normally 2 oscilloscopes are kept for viewing beam at two successive points along with one channel selector to select the channel to be monitored. The 8 channel beam profile digitizer being developed is a low cost intelligent PC-add on card, built around Intel's 8751 microcontroller, which can be easily integrated with PC based data acquisition and control system for accelerators. Microcontroller digitizes the signal and stores information on FIFO for PC to read and graphically display the profile. User can select up to 8 profiles to view simultaneously on the screen. (author). 1 ref., 2 figs

  7. ATLAS diamond Beam Condition Monitor

    CERN Document Server

    Gorišek, A; Dolenc, I; Frais-Kölbl, H; Griesmayer, E; Kagan, H; Korpar, S; Kramberger, G; Mandic, I; Meyer, M; Mikuz, M; Pernegger, H; Smith, S; Trischuk, W; Weilhammer, P; Zavrtanik, M

    2007-01-01

    The ATLAS experiment has chosen to use diamond for its Beam Condition Monitor (BCM) given its radiation hardness, low capacitance and short charge collection time. In addition, due to low leakage current diamonds do not require cooling. The ATLAS Beam Condition Monitoring system is based on single beam bunch crossing measurements rather than integrating the accumulated particle flux. Its fast electronics will allow separation of LHC collisions from background events such as beam gas interactions or beam accidents. There will be two stations placed symmetrically about the interaction point along the beam axis at . Timing of signals from the two stations will provide almost ideal separation of beam–beam interactions and background events. The ATLAS BCM module consists of diamond pad detectors of area and thickness coupled to a two-stage RF current amplifier. The production of the final detector modules is almost done. A S/N ratio of 10:1 has been achieved with minimum ionizing particles (MIPs) in the test bea...

  8. Relativistic electron beams above thunderclouds

    Directory of Open Access Journals (Sweden)

    M. Füllekrug

    2011-08-01

    Full Text Available Non-luminous relativistic electron beams above thunderclouds have been detected by the radio signals of low frequency ∼40–400 kHz which they radiate. The electron beams occur ∼2–9 ms after positive cloud-to-ground lightning discharges at heights between ∼22–72 km above thunderclouds. Intense positive lightning discharges can also cause sprites which occur either above or prior to the electron beam. One electron beam was detected without any luminous sprite which suggests that electron beams may also occur independently of sprites. Numerical simulations show that beams of electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of ∼7 MeV to transport a total charge of ∼−10 mC upwards. The impulsive current ∼3 × 10−3 Am−2 associated with relativistic electron beams above thunderclouds is directed downwards and needs to be considered as a novel element of the global atmospheric electric circuit.

  9. Beam diagnostics with synchrotron radiation

    International Nuclear Information System (INIS)

    Synchrotron radiation is often used to measure the dimensions of an electron beam. The transverse size is obtained from an image of the beam cross section formed by means of the emitted synchrotron radiation. Because of the small natural opening angle the resolution is limited by diffraction. The angular spread of the particles in the beam can be measured by observing the radiation directly. Here, the resolution is limited by the natural opening angle of the emitted light. Measuring both beam cross section and angular spread gives the emittance of the beam. However, in most cases only one of these two parameters is observed and the other deduced from the known particle beam optics at the source of the radiation. Usually one observes radiation emitted in long bending magnets. However, short magnets and undulators are also useful sources for these measurements. For practical reasons the beam diagnostics is carried out using visible or ultraviolet light. This part of the spectrum is usually far below the critical frequency, and corresponding approximations can be applied. Synchrotron radiation is an extremely useful tool for diagnostics in electron (or positron) rings. In some cases it has also served in proton rings using special magnets. (author)

  10. Effect of beam oscillation on borated stainless steel electron beam welds

    International Nuclear Information System (INIS)

    Borated stainless steels are used in nuclear power plants to control neutron criticality in reactors as control rods, shielding material, spent fuel storage racks and transportation casks. In this study, bead on plate welds were made using gas tungsten arc welding (GTAW) and electron beam welding (EBW) processes. Electron beam welds made using beam oscillation technique exhibited higher tensile strength values compared to that of GTA welds. Electron beam welds were found to show fine dendritic microstructure while GTA welds exhibited larger dendrites. While both processes produced defect free welds, GTA welds are marked by partially melted zone (PMZ) where the hardness is low. EBW obviate the PMZ failure due to low heat input and in case of high heat input GTA welding process failure occurs in the PMZ.

  11. Surface modification produced by a nitrogen operated plasma focus device: the role of the ion beam in the heating of a substrate

    Science.gov (United States)

    Lepone, A.; Kelly, H.; Lamas, D.; Márquez, A.

    1999-04-01

    The role of the nitrogen ion beam generated with a small energy plasma focus (PF) device in the thermal processing of an austenitic stainless steel substrate is discussed. A numerical solution of the heat equation which takes into account the temperature variations of the thermal coefficients of the material is presented. By using several characteristics of the beam determined in previous works, it is found that the energy content of the beam is not enough to promote a strong heating of the outer layers of the substrate, which is required to explain the introduction of foreign particles to depths well beyond the ion range in the material, and also the martensitic transformation of steel up to a depth of ≈0.6 μm found in this work. The surface treatment is thus attributed to a plasma bubble generated by the disruption of the plasma column, and some evidence of its presence is obtained by employing a Faraday cup (FC). When the numerical model is used with an input energy density corresponding to the experimental value, and with a delivery time equal to the temporal width of the bubble, the evolution of the temperature profiles along the substrate depth shows a melting front reaching the proper depth to explain the penetration of Ti and N atoms found in a previous work, and the martensitic transformation depth presented in this work.

  12. Beam line to S155

    CERN Multimedia

    1977-01-01

    The experiment S155 was designed by the Orsay (CSNM-CNRS) Collaboration to observe the properties of exotic light nuclei. It was installed in the PS neutrino tunnel. The photo shows a mass spectrometer (in the background) on line with the PS proton beam which arrives (bottom, right) from the fast extraction FE74. Roger Fergeau stands on the left. The alkaline isotopes produced in the carbon-uranium target heated at 2000°C were swiftly extracted, mass separated, and brought to a detector behind the shielding. Sodium 34 (11 protons and 23 neutrons) was observed and its half-life of only 5 ms was measured. The excited levels 2+ of Magnesium 30 and Magnesium 32 (Sodium descendants) were localised, and the magic number 20 was found to vanish. Thus, the discovery made earlier for Sodium 30 and Sodium 32, with the same apparatus, was confirmed. (See also photo 7706511.)

  13. Electron beam machining using rotating and shaped beam power distribution

    Science.gov (United States)

    Elmer, John W.; O'Brien, Dennis W.

    1996-01-01

    An apparatus and method for electron beam (EB) machining (drilling, cutting and welding) that uses conventional EB guns, power supplies, and welding machine technology without the need for fast bias pulsing technology. The invention involves a magnetic lensing (EB optics) system and electronic controls to: 1) concurrently bend, focus, shape, scan, and rotate the beam to protect the EB gun and to create a desired effective power-density distribution, and 2) rotate or scan this shaped beam in a controlled way. The shaped beam power-density distribution can be measured using a tomographic imaging system. For example, the EB apparatus of this invention has the ability to drill holes in metal having a diameter up to 1000 .mu.m (1 mm or larger), compared to the 250 .mu.m diameter of laser drilling.

  14. Cluster beam sources. Part 1. Methods of cluster beams generation

    Directory of Open Access Journals (Sweden)

    A.Ju. Karpenko

    2012-10-01

    Full Text Available The short review on cluster beams generation is proposed. The basic types of cluster sources are considered and the processes leading to cluster formation are analyzed. The parameters, that affects the work of cluster sources are presented.

  15. Reconstruction of negative hydrogen ion beam properties from beamline diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Ruf, Benjamin

    2014-09-25

    For the experimental fusion reactor ITER, which should show the feasibility of sustaining a fusion plasma with a positive power balance, some technology still has to be developed, amongst others also the plasma heating system. One heating technique is the neutral beam injection (NBI). A beam of fast deuterium atoms is injected into the fusion plasma. By heavy particle collisions the beam particles give their energy to the plasma. A NBI system consists of three major components. First, deuterium ions are generated in a low temperature, low pressure plasma of an ion source. At ITER, the requirements on the beam energy of 1 MeV cause the necessity of negative charged deuterium ions. Secondly, the ions are accelerated within an acceleration system with several grids, where the plasma grid is the first grid. The grids are on different descending high voltage potentials. The source itself is on the highest negative potential. Thirdly, the fast deuterium ions have to be neutralised. This thesis deals with the second step in the mentioned beam system, the ion acceleration and beam formation. The underlying experiments and measurements were carried out at the testbeds BATMAN (BAvarianTest MAchine for Negative ions) and ELISE (Extraction from a Large Ion Source Experiment) at the Max-Planck-Institut fuer Plasmaphysik Garching (IPP Garching). The main goal of this thesis is to provide a tool which allows the determination of the beam properties. These are beam divergence, stripping losses and beam inhomogeneity. For this purpose a particle trajectory code has been developed from scratch, namely BBC-NI (Bavarian Beam Code for Negative Ions). The code is able to simulate the whole beam and the outcome of several beam diagnostic tools. The data obtained from the code together with the measurements of the beam diagnostic tools should allow the reconstruction of the beam properties. The major beam diagnostic tool, which is used in this thesis, is the beam emission spectroscopy

  16. Longitudinal compression of ion beams

    International Nuclear Information System (INIS)

    This paper examines the longitudinal compression of ion beams which is necessary in some designs of drivers intended to realize inertial thermonuclear fusion by heavy ions. Taking space-charge forces in the beams into account, two compression schemes are investigated: the first preserves the longitudinal phase-space area of the beams, and the second allows an increase of the phase-space area. The compression-system parameters are optimized for an example of a driver for inertial thermonuclear fusion by heavy ions with an energy of 10 MJ and with a pulse length of 25 ns on the target

  17. Photoelectron photoion molecular beam spectroscopy

    International Nuclear Information System (INIS)

    The use of supersonic molecular beams in photoionization mass spectroscopy and photoelectron spectroscopy to assist in the understanding of photoexcitation in the vacuum ultraviolet is described. Rotational relaxation and condensation due to supersonic expansion were shown to offer new possibilities for molecular photoionization studies. Molecular beam photoionization mass spectroscopy has been extended above 21 eV photon energy by the use of Stanford Synchrotron Radiation Laboratory (SSRL) facilities. Design considerations are discussed that have advanced the state-of-the-art in high resolution vuv photoelectron spectroscopy. To extend gas-phase studies to 160 eV photon energy, a windowless vuv-xuv beam line design is proposed

  18. A polarized atomic hydrogen beam

    International Nuclear Information System (INIS)

    We describe the design and operating characteristics of a simple polarized atomic hydrogen beam particularly suitable for applications to crossed beams experiments. In addition to experimental measurements, we present the results of detailed computer models, using Monte-Carlo ray tracing techniques, optical analogs, and phase-space methods, that not only provide us with a confirmation of our measurement, but also allow us to characterize the density, polarization, and atomic fraction of the beam at all points along its path. As a subsidiary result, we also present measurements of the relative and absolute efficiencies of the V/G Supavac mass analyzer for masses 1 and 2. (orig.)

  19. Beam Transfer and Machine Protection

    CERN Document Server

    Kain, V

    2016-01-01

    Beam transfer, such as injection into or extraction from an accelerator, is one of the most critical moments in terms of machine protection in a high-intensity machine. Special equipment is used and machine protection aspects have to be taken into account in the design of the beam transfer concepts. A brief introduction of the principles of beam transfer and the equipment involved will be given in this lecture. The main concepts of machine protection for injection and extraction will be presented, with examples from the CERN SPS and LHC.

  20. BR2 reactor neutron beams

    International Nuclear Information System (INIS)

    The use of reactor neutron beams is becoming increasingly more widespread for the study of some properties of condensed matter. It is mainly due to the unique properties of the ''thermal'' neutrons as regards wavelength, energy, magnetic moment and overall favorable ratio of scattering to absorption cross-sections. Besides these fundamental reasons, the impetus for using neutrons is also due to the existence of powerful research reactors (such as BR2) built mainly for nuclear engineering programs, but where a number of intense neutron beams are available at marginal cost. A brief introduction to the production of suitable neutron beams from a reactor is given. (author)

  1. Electron beam, laser beam and plasma arc welding studies

    Science.gov (United States)

    Banas, C. M.

    1974-01-01

    This program was undertaken as an initial step in establishing an evaluation framework which would permit a priori selection of advanced welding processes for specific applications. To this end, a direct comparison of laser beam, electron beam and arc welding of Ti-6Al-4V alloy was undertaken. Ti-6Al-4V was selected for use in view of its established welding characteristics and its importance in aerospace applications.

  2. Target development for a radioactive ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Arnould, M.; Vanhorenbeeck, J. (Universite Libre de Bruxelles (Belgium). Inst. d' Astronomie et d' Astrophysique); Baeten, F.; Dom, C. (Institut National des Radioelements, Fleurus (Belgium)); Darquennes, D.; Delbar, T.; Jongen, Y.; Lacroix, M.; Lipnik, P.; Loiselet, M.; Ryckewaert, G.; Wa Kitwanga, S.; Vervier, J.; Zaremba, S. (Louvain Univ., Louvain-la-Neuve (Belgium). Centre de Physique Nucleaire; Louvain Univ., Louvain-la-Neuve (Belgium). Lab. de Cyclotron); Huyse, M.; Reusen, G.; Duppen, P. van (Leuven Univ. (Belgium). Inst. voor Kern- en Stralingsfysika)

    1989-10-01

    A proton bombarded target coupled to an ion source is a key-equipment to produce a cyclotron accelerated Radioactive Ion Beam (RIB). This note concerns the target development for a {sup 13}N ion beam which will be the first one out of a more general project at Louvain-la-Neuve (Report RIB-1988-01). A 30-MeV proton beam of up to 300-{mu}A intensity from the CYCLONE 30 bombards a graphite target to produce the {sup 13}N isotope via the {sup 13}C(p, n){sup 13}N reaction. Two major problems have to be solved: The extraction and transport of {sup 13}N and the beam-heat dissipation. These aspects are somewhat correlated to the temperature dependence of the {sup 13}N release and to the heat conductivity of graphite. A disk shaped target can be cooled through its side-face or through its back-face, and in fact both designs are explored. The extraction yield of the first one varies with the beam intensity up to a maximum value of 46% at 170 {mu}A. For the second one, which is presently under development, the target temperature can be adjusted by a cooled finger of variable length. (orig.).

  3. Monitoring external beam radiotherapy using real-time beam visualization

    International Nuclear Information System (INIS)

    Purpose: To characterize the performance of a novel radiation therapy monitoring technique that utilizes a flexible scintillating film, common optical detectors, and image processing algorithms for real-time beam visualization (RT-BV). Methods: Scintillating films were formed by mixing Gd2O2S:Tb (GOS) with silicone and casting the mixture at room temperature. The films were placed in the path of therapeutic beams generated by medical linear accelerators (LINAC). The emitted light was subsequently captured using a CMOS digital camera. Image processing algorithms were used to extract the intensity, shape, and location of the radiation field at various beam energies, dose rates, and collimator locations. The measurement results were compared with known collimator settings to validate the performance of the imaging system. Results: The RT-BV system achieved a sufficient contrast-to-noise ratio to enable real-time monitoring of the LINAC beam at 20 fps with normal ambient lighting in the LINAC room. The RT-BV system successfully identified collimator movements with sub-millimeter resolution. Conclusions: The RT-BV system is capable of localizing radiation therapy beams with sub-millimeter precision and tracking beam movement at video-rate exposure

  4. Test Beam Coordination: 2003 ATLAS Combined Test Beam

    CERN Multimedia

    Di Girolamo, B.

    The 2003 Test Beam Period The 2003 Test Beam period has been very fruitful for ATLAS. In spite of several days lost because of the accelerator problems, ATLAS has been able to achieve many results: FCAL has completed the calibration program in H6 Tilecal has completed the calibration program in H8 Pixel has performed extensive studies with normal and high intensity beams (up to 1.4*108 hadrons/spill) SCT has completed a variety of studies with quite a high number of modules operated concurrently TRT has performed several studies at high, low and very low energy (first use of the new H8 beam in the range 1 to 9 GeV) Muons (MDT,RPC and TGC) have been operating a large setup for about 5 months. The almost final MDT ROD (MROD) has been integrated in the readout and the final trigger electronics for TGC and RPC has been tested and certified with normal beam and during dedicated 40 MHz beam periods. The TDAQ has exploited a new generation prototype successfully and the new Event Filter infrastructure f...

  5. Investigation of in situ and conventional post-weld heat treatments on dual-laser-beam-welded {gamma}-TiAl-based alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jie; Ventzke, Volker; Kashaev, Nikolai; Huber, Norbert [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Materials Mechanics Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Staron, Peter; Schell, Norbert [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Materials Physics Max-Planck-Strasse 1, 21502 Geesthacht (Germany)

    2012-10-15

    This paper describes a way to improve the microstructure and mechanical properties of welding seams by in situ and conventional post-weld heat treatments for laser beam welding of the Ti-45Al-5Nb-0.2C-0.2B alloy. The seams are crack-free with reduced longitudinal residual stress and higher elongation to fraction after post-weld heat treatment. The welding zone consists of {alpha}{sub 2} after welding, transforms to a massive {gamma} during in situ post-weld heat treatment, and finally forms a convoluted microstructure after conventional heating. The phase composition across the welding zone is discussed. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Effect of Prior and Post-Weld Heat Treatment on Electron Beam Weldments of (α + β) Titanium alloy Ti-5Al-3Mo-1.5V

    Science.gov (United States)

    Anil Kumar, V.; Gupta, R. K.; Manwatkar, Sushant K.; Ramkumar, P.; Venkitakrishnan, P. V.

    2016-06-01

    Titanium alloy Ti5Al3Mo1.5V is used in the fabrication of critical engine components for space applications. Double vacuum arc re-melted and (α + β) forged blocks were sliced into 10-mm-thick plates and subjected to electron beam welding (EBW) with five different variants of prior and post-weld heat treatment conditions. Effects of various heat treatment conditions on the mechanical properties of the weldments have been studied. The welded coupons were characterized for microstructure, mechanical properties, and fracture analysis. An optimized heat treatment and welding sequence has been suggested. Weld efficiency of 90% could be achieved. Weldment has shown optimum properties in solution treated and aged condition. Heat-affected zone adjacent to weld fusion line is found to have lowest hardness in all conditions.

  7. Beam Effects on the Cryogenic System of LEP2

    CERN Document Server

    Gayet, P; Winkler, G

    1998-01-01

    The LEP collider was operated during 1996 for the first time with superconducting cavities at the four interaction points. During operation for physics it was observed that the dissipated heat in the cavities is not only a function of the acceleration gradient, but depends also on beam characteristics such as intensity, bunch length and beam current. These beam effects had not been foreseen in the original heat budget of the LEP cryogenic system. The observations indicating the beam effect and its origin are presented. The available capacity of the refrigerators demonstrates that cryogenics might become a limiting factor for the performance of the LEP collider.

  8. Generating stable tractor beams with dielectric metasurfaces

    Science.gov (United States)

    Pfeiffer, Carl; Grbic, Anthony

    2015-03-01

    Propagation-invariant beams that pull objects towards a light source are commonly known as tractor beams. Here, an efficient, linearly polarized tractor beam with improved stability is introduced. The beam consists of a superposition of transverse-electric and transverse-magnetic polarized Bessel beams of orders m =+1 and m =-1 . It is shown that this beam can stably pull a wide range of dielectric microparticles arbitrarily long distances, independent of ambient conditions. Next, a straightforward method of generating these high-performance beams is proposed. A Si metasurface transforms an incident linearly polarized Gaussian beam into the desired tractor beam. Full-wave simulations demonstrate that it is possible for this simple geometry to pull a polystyrene sphere a distance equal to the nondiffracting range of the Bessel beam. The simplicity of the setup and the robust performance of the proposed tractor beam significantly enhance the ability to manipulate matter with light.

  9. Monitor of SC beam profiles

    CERN Multimedia

    1977-01-01

    A high-resolution secondary emission grid for the measurement of SC beam profiles. Modern techniques of metal-ceramic bonding, developed for micro-electronics, have been used in its construction. (See Annual Report 1977 p. 105 Fig. 12.)

  10. Center for Beam Physics, 1992

    International Nuclear Information System (INIS)

    This report contains the following information on the center for beam physics: Facilities; Organizational Chart; Roster; Profiles of Staff; Affiliates; Center Publications (1991--1993); and 1992 Summary of Activities

  11. ATF beam image monitor software

    International Nuclear Information System (INIS)

    We report about software for the beam image analysis at ATF. We developed image analysis software with a Linux computer. It acquire image data from a video and an IEEE1394 digital camera of the analog. (author)

  12. Quantum fluctuations in beam dynamics

    International Nuclear Information System (INIS)

    Quantum effects could become important for particle and photon beams used in high-luminosity and high brightness applications in the current and next generation accelerators and radiation sources. This paper is a review of some of these effects

  13. LHC beam loss pattern recognition

    CERN Document Server

    Marsili, A; Puzo, P

    2011-01-01

    One of the systems protecting CERN’s Large Hadron Collider (LHC) is the Beam Loss Monitoring system (BLM). More than 3600 monitors are installed around the ring. The beam losses are permanently integrated over 12 different time intervals (from 40 microseconds to 84 seconds). When any loss exceeds the thresholds defined for the integration window, the beam is removed from the machine. Understanding the origin of a beam loss is crucial for machine operation, as it can help to avoid a repetition of the same scenario. The signals read from given monitors can be considered as entries of a vector. This article presents how a loss map of unknown cause can be decomposed using vector based analysis derived from well-known loss scenarios. The algorithms achieving this decomposition are described, as well as the accuracy of the results.

  14. Libera Electron Beam Position Processor

    CERN Document Server

    Ursic, Rok

    2005-01-01

    Libera is a product family delivering unprecedented possibilities for either building powerful single station solutions or architecting complex feedback systems in the field of accelerator instrumentation and controls. This paper presents functionality and field performance of its first member, the electron beam position processor. It offers superior performance with multiple measurement channels delivering simultaneously position measurements in digital format with MHz kHz and Hz bandwidths. This all-in-one product, facilitating pulsed and CW measurements, is much more than simply a high performance beam position measuring device delivering micrometer level reproducibility with sub-micrometer resolution. Rich connectivity options and innate processing power make it a powerful feedback building block. By interconnecting multiple Libera electron beam position processors one can build a low-latency high throughput orbit feedback system without adding additional hardware. Libera electron beam position processor ...

  15. Electrostatic beam-position monitor

    CERN Multimedia

    CERN PhotoLab

    1969-01-01

    Electrostatic beam-position monitor installed in its final location (bake-out cover removed). The ISR will contain about 110 of these monitors. Their accuracy is better than 1 mm, their band width about 1 MHz.

  16. Center for Beam Physics, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1993-06-01

    This report contains the following information on the center for beam physics: Facilities; Organizational Chart; Roster; Profiles of Staff; Affiliates; Center Publications (1991--1993); and 1992 Summary of Activities.

  17. Beam emittance measurements in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Zelenski,A.; Bazilevsky, A.; Bunce, G.; Gill, R.; Huang, H.; Makdisi, Y.; Morozov, B.; Nemesure, S.; Russo, t.; Steski, D.; Sivertz, M.

    2009-05-04

    The RHIC proton polarimeters can operate in scanning mode, giving polarization profiles and transverse beam intensity profile (beam emittance) measurements. The polarimeters function as wire scanners, providing a very good signal/noise ratio and high counting rate. This allows accurate bunch-by-bunch emittance measurements during fast target sweeps (<1 s) through the beam. Very thin carbon strip targets make these measurements practically non-destructive. Bunch by bunch emittance measurements are a powerful tool for machine set-up; in RHIC, individual proton beam transverse emittances can only be measured by CNI polarimeter scans. We discuss the consistency of these measurements with Ionization Profile Monitors (IPMs) and vernier scan luminosity measurements. Absolute accuracy limitations and cross-calibration of different techniques are also discussed.

  18. RIKEN RI Beam Factory project

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Yasushige; Goto, Akira; Katayama, Takeshi [Institute of Physical and Chemical Research, Wako, Saitama (Japan)

    1997-03-01

    The RARF proposes `RIKEN RI Beam Factory` as a next facility-expanding project. The factory makes it the primary aim to provide RI (Radioactive Isotope) beams covering over the whole atomic-mass range with the world-highest intensity in a wide energy range up to several hundreds MeV/nucleon. These RI beams are generated by the fragmentation of high-intensity heavy-ion beams. For the efficient production heavy-ion energies will be boosted up to over 100 MeV/nucleon even for very heavy ions by a K2500-MeV superconducting ring cyclotron serving as a post accelerator of the existing K540-MeV ring cyclotron. A new type of experimental installation called `MUSES` (Multi-USe Experimental Storage rings) will be constructed as well. With MUSES, various types of unique colliding experiments will become possible. (author)

  19. Beam screen cryogenic control improvements for the LHC run 2

    CERN Document Server

    Bradu, Benjamin; Blanco Vinuela, Enrique; Ferlin, Gerard; Tovar-Gonzalez, Antonio

    2016-01-01

    This paper presents the improvements performed on the cryogenic control system for the LHC beam screens. The regulation objective is to maintain an acceptable temperature range around 20 K that ensures a good LHC beam vacuum and that limits cryogenic heat loads. In total, there are 485 regulation loops around the 27 km of the LHC machine affected by these beam disturbances. Due to the increase of the LHC performance during the run 2, standard PID controllers manage with difficulties the temperature transients of the beam screens. Several alternative control techniques have been studied and validated using dynamic simulation and then deployed on the LHC cryogenic control system in 2015. The main contribution is the addition of a feed-forward control in order to compensate the beam effects on the beam screen temperature based on the main beam parameters of the machine in real time.

  20. Design of Neutral Beam-Line of EAST

    Institute of Scientific and Technical Information of China (English)

    胡纯栋; 盛鹏; 许永建; 梁立振; 谢远来; 韦江龙; 谢亚红; 李军; 刘智民; 刘胜; 蒋才超

    2011-01-01

    Neutral beam injector for EAST is designed to deliver deuterium beams with a power of 2 MW to 4 MW at an energy of 50 keV to 80 keV into the plasma with a beam dimension of 12 cm× 48 cm. Considering the beam generation and transmission, a columniform beam-line of Ф 250 cm × 400 cm is designed with a neutralizer, ion dump, calorimeter, bending magnet and cryopanels. The arrangement of the internal elements for the beam-line is reported. A rectangular sleeve coupled to the ion source is employed as the neutralizer. At the downstream of the neutralizer, a dipole magnet separates the residual ions from the beam passage with a reflection radius of 42 cm for the full energy particles. The calorimeter and the ion dump serve as high heat flux components, which will work as thermal inertia targets in the first phase of operation.

  1. Beam screen cryogenic control improvements for the LHC run 2

    CERN Document Server

    Bradu, Benjamin; Blanco Vinuela, Enrique; Ferlin, Gerard; Tovar-Gonzalez, Antonio

    2016-01-01

    This paper presents the improvements made on the cryogenic control system for the LHC beam screens. The regulation objective is to maintain an acceptable temperature range around 20 K which simultaneously ensures a good LHC beam vacuum and limits cryogenic heat loads. In total, through the 27 km of the LHC machine, there are 485 regulation loops affected by beam disturbances. Due to the increase of the LHC performance during Run 2, standard PID controllers cannot keeps the temperature transients of the beam screens within desired limits. Several alternative control techniques have been studied and validated using dynamic simulation and then deployed on the LHC cryogenic control system in 2015. The main contribution is the addition of a feed-forward control in order to compensate the beam effects on the beam screen temperature based on the main beam parameters of the machine in real time.

  2. A polarized atomic hydrogen beam

    OpenAIRE

    Chan, N; Crowe, D.M.; Lubell, M. S.; Tang, F.C.; Vasilakis, A.; Mulligan, F. J.; Slevin, J.

    1988-01-01

    We describe the design and operating characteristics of a simple polarized atomic hydrogen beam particularly suitable for applications to crossed beams experiments. In addition to experimental measurements, we present the results of detailed computer models, using Monte-Carlo ray tracing techniques, optical analogs, and phase-space methods, that not only provide us with a confirmation of our measurement, but also allow us to characterize the density, polarization, and atomic fraction of the b...

  3. Equipment for ion beam production

    International Nuclear Information System (INIS)

    An equipment has been designed to extend the scope of control of ion beam flux for an intensive ion beam source used for plasma injection in magnetic vessels. The control equipment is connected to the electromagnet power supply. A consumption regulator is fitted in the operating gas supply to the hollow cathode of the ion source. A circuit is also included for discharge voltage maintenance consisting of a control element and a discharge voltage pick-up. (M.D.). 1 fig

  4. Generation and study of relativistic electron beam

    International Nuclear Information System (INIS)

    Pulsed Electron Beam (REB) technology has progressed rapidly in recent years because of applications in various fields like radiation sources, high power laser development, plasma heating and fusion research. The REB development programme at the Plasma Physics Section of Bhabha Atomic Research Centre, Bombay, has been described. The design features of the 375 KV, 3500 A, 75 Joule REB generator are discussed. The diagnostic equipment developed for the studies is described. The present experimental studies and some preliminary results on beam characterisation are presented. (author)

  5. Airy beam optical parametric oscillator.

    Science.gov (United States)

    Aadhi, A; Chaitanya, N Apurv; Jabir, M V; Vaity, Pravin; Singh, R P; Samanta, G K

    2016-01-01

    Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51-1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond). PMID:27143582

  6. Airy beam optical parametric oscillator.

    Science.gov (United States)

    Aadhi, A; Chaitanya, N Apurv; Jabir, M V; Vaity, Pravin; Singh, R P; Samanta, G K

    2016-05-04

    Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51-1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond).

  7. Airy beam optical parametric oscillator

    Science.gov (United States)

    Aadhi, A.; Chaitanya, N. Apurv; Jabir, M. V.; Vaity, Pravin; Singh, R. P.; Samanta, G. K.

    2016-05-01

    Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51–1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond).

  8. The ELENA Beam Diagnostics Systems

    CERN Document Server

    Tranquille, G

    2013-01-01

    The Extra Low ENergy Antiproton ring (ELENA) to be built at CERN is aimed at substantially increasing the number of antiprotons to the low energy antiproton physics community. It will be a small machine which will decelerate low intensity beams (<4x107) from 5.3 MeV to 100 keV and will be equipped with an electron cooler to avoid beam losses during the deceleration and to significantly reduce beam phase space at extraction. To measure the beam parameters from the extraction point of the Antiproton Decelerator (AD), through the ELENA ring and all the way to the experiments, many systems will be needed to ensure that the desired beam characteristics are obtained. Particular attention needs to be paid to the performance of the electron cooler which depends on reliable instrumentation in order to efficiently cool the antiprotons. This contribution will present the different monitors that have been proposed to measure the various beam parameters as well as some of the developments going on to further improve th...

  9. Behavior of reinforcement SCC beams under elevated temperatures

    Science.gov (United States)

    Fathi, Hamoon; Farhang, Kianoosh

    2015-09-01

    This experimental study focuses on the behavior of heated reinforced concrete beams. Four types of concrete mixtures were used for the tested self-compacting concrete beams. A total of 72 reinforced concrete beams and 72 standard cylindrical specimens were tested. The compressive strength under uniaxial loading at 23 °C ranged from 30 to 45 MPa. The specimens were exposed to different temperatures. The test parameters of interest were the compressive strength and the temperature of the specimens. The effect of changes in the parameters was examined so as to control the behavior of the tested concrete and that of the reinforced concrete beam. The results indicated that flexibility and compressive strength of the reinforced concrete beams decreased at higher temperatures. Furthermore, heating beyond 400 °C produced greater variations in the structural behavior of the materials in both the cylindrical samples and the reinforced concrete beams.

  10. Diplexer for laser-beam heterodyne receiver

    Science.gov (United States)

    Koepf, G.

    1981-01-01

    Four prism interferometer superposes local oscillator beam on signal beam. Position of movable prism directs incident energy in both beams out one output port. Output port is spatially separated from input ports, and there is no limitation on size of frequency difference between laser beams.

  11. KTeV beam systems design report

    Energy Technology Data Exchange (ETDEWEB)

    Bocean, V.; Childress, S.; Coleman, R. [and others

    1997-09-01

    The primary and secondary beams for the KTeV experiments E799-II and E832 are discussed. The specifications are presented and justified. The technical details of the implementation of the primary beam transport and stability are detailed. The target, beam dump, and radiation safety issues are discussed. The details of the collimation system for the pair of secondary beams are presented.

  12. Electron optics of microlenses with inclined beams

    NARCIS (Netherlands)

    Zhang, Y.; Barth, J.E.; Kruit, P.

    2008-01-01

    For multielectron beam systems with a single electron source, the outside beams need to be collimated before entering the individual microcolumns. As an alternative of the traditional multibeam source design where the broad beam from the source is collimated by a single lens, the broad beam can be f

  13. Beam instrumentation in a multidisciplinary accelerator facility

    NARCIS (Netherlands)

    Schippers, J.M.; Boon, S.N.; Dermois, O.C.; Kiewiet, H.H.

    1998-01-01

    Some recently developed beam diagnostic devices for the beam lines of the AGOR cyclotron are reviewed. The range of applications is from low background nuclear physics experiments at "zero degree" to radiation therapy with proton beams. In particular a method to improve beam quality and the performa

  14. Beam buncher for the K130-cyclotron

    Science.gov (United States)

    Saario, J.; Gustafsson, J.; Kotilainen, P.; Kaski, K.; Lassila, A.; Liukkonen, E.

    1996-02-01

    A beam buncher, developed to improve the beam efficiency in the K130 cyclotron at University of Jyväskylä, is described. The basic acceleration frequency and the second harmonic component were used to simulate a saw-tooth wave, needed for axial injection of the beam. With this method up to eight times increase in the beam intensity was achieved.

  15. Beam buncher for the K130-cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Saario, J. [Tampere Univ. of Technol. (Finland). Microelectronics Lab.; Gustafsson, J. [Tampere Univ. of Technol. (Finland). Microelectronics Lab.; Kotilainen, P. [Tampere Univ. of Technol. (Finland). Microelectronics Lab.; Kaski, K. [Tampere Univ. of Technol. (Finland). Microelectronics Lab.; Lassila, A. [Jyvaeskylae Univ. (Finland). Dept. of Physics; Liukkonen, E. [Jyvaeskylae Univ. (Finland). Dept. of Physics

    1996-02-21

    A beam buncher, developed to improve the beam efficiency in the K130 cyclotron at University of Jyvaeskylae, is described. The basic acceleration frequency and the second harmonic component were used to simulate a saw-tooth wave, needed for axial injection of the beam. With this method up to eight times increase in the beam intensity was achieved. (orig.).

  16. Luminosity Loss due to Beam Distortion and the Beam-Beam Instability

    CERN Document Server

    Wu, Juhao; Raubenheimer, Tor O; Seryi, Andrei; Sramek, Christopher K

    2005-01-01

    In a linear collider, sources of emittance dilution such as transverse wakefields or dispersive errors will couple the vertical phase space to the longitudinal position within the beam (the so-called ‘banana effect'). When the Intersection Point (IP) disruption parameter is large, these beam distortions will be amplified by a single bunch kink instability which will lead to luminosity loss. We study this phenomena both analytically using linear theory and via numerical simulation. In particular, we examine the dependence of the luminosity loss on the wavelength of the beam distortions and the disruption parameter. This analysis may prove useful when optimizing the vertical disruption parameter for luminosity operation with given beam distortions.

  17. Vibrating Wire for Beam Profile Scanning

    CERN Document Server

    Arutunian, S G; Mailian, M R; Sinenko, I G; Vasiniuk, I E

    1999-01-01

    The method for measurement of transverse profile (emittance) of the bunch by detecting of radiation arising scattering at of the bunch on the scanning wire is wide-spread. In this work the information about scattering bunch is proposed to measure using the oscillation frequency of the tightened scanning wire. In such way the system of radiation (or secondary particles) extraction and measurement can be removed. Dependence of oscillations frequency on beam scattering is determined by several factors, including changes of wire tension caused by transverse force of the beam, influence of beam self field. Preliminary calculations show that influence caused by wire heating will dominate. We have studied strain gauges on the basis of vibrating wire from various materials (tungsten, beryl bronze, niobium zirconium alloys). A scheme of self oscillations generation by alternating current in autogeneration circuit with automatic frequency adjustment was selected. Special method of wire fixation and elimination of trans...

  18. Laser beam propagation in a long solenoid

    International Nuclear Information System (INIS)

    An analysis of the propagation of a laser beam in a cylindrical magnetically confined plasma with parabolic density profile is presented. The normal modes which are self-trapped are given. It is found that the largest mode that can be trapped by the plasma is given by 1/2 (R02/w2 -- 1) where R0 is the radius of the plasma column and w is the fundamental mode width. It is found that all the trapped modes in a finite plasma can easily propagate distances of the order of one kilometer. An exact solution for the amplitude of the electric field for an incident gaussian beam was obtained. The solution exhibits alternate focusing and defocusing of the beam. The effect of this on the plasma heating is discussed. (U.S.)

  19. A Neutral Beam Injector Upgrade for NSTX

    Energy Technology Data Exchange (ETDEWEB)

    T. Stevenson; B McCormack; G.D. Loesser; M. Kalish; S. Ramakrishnan; L. Grisham; J. Edwards; M. Cropper; G. Rossi; A. von Halle; M. Williams

    2002-01-18

    The National Spherical Torus Experiment (NSTX) capability with a Neutral Beam Injector (NBI) capable of 80 kiloelectronvolt (keV), 5 Megawatt (MW), 5 second operation. This 5.95 million dollar upgrade reused a previous generation injector and equipment for technical, cost, and schedule reasons to obtain these specifications while retaining a legacy capability of 120 keV neutral particle beam delivery for shorter pulse lengths for possible future NSTX experiments. Concerns with NBI injection included power deposition in the plasma, aiming angles from the fixed NBI fan array, density profiles and beam shine through, orbit losses of beam particles, and protection of the vacuum vessel wall against beam impingement. The upgrade made use of the beamline and cryo panels from the Neutral Beam Test Stand facility, existing power supplies and controls, beamline components and equipment not contaminated by tritium during DT [deuterium-tritium] experiments, and a liquid Helium refrigerator plant to power and cryogenically pump a beamline and three ion sources. All of the Tokamak Fusion Test Reactor (TFTR) ion sources had been contaminated with tritium, so a refurbishment effort was undertaken on selected TFTR sources to rid the three sources destined for the NSTX NBI of as much tritium as possible. An interconnecting duct was fabricated using some spare and some new components to attach the beamline to the NSTX vacuum vessel. Internal vacuum vessel armor using carbon tiles was added to protect the stainless steel vacuum vessel from beam impingement in the absence of plasma and interlock failure. To date, the NBI has operated to 80 keV and 5 MW and has injected requested power levels into NSTX plasmas with good initial results, including high beta and strong heating characteristics at full rated plasma current.

  20. Detection of Equipment Faults Before Beam Loss

    CERN Document Server

    Galambos, J

    2016-01-01

    High-power hadron accelerators have strict limits on fractional beam loss. In principle, once a high-quality beam is set up in an acceptable state, beam loss should remain steady. However, in practice, there are many trips in operational machines, owing to excessive beam loss. This paper deals with monitoring equipment health to identify precursor signals that indicate an issue with equipment that will lead to unacceptable beam loss. To this end, a variety of equipment and beam signal measurements are described. In particular, several operational examples from the Spallation Neutron Source (SNS) of deteriorating equipment functionality leading to beam loss are reported.

  1. SYNCHROTRON OSCILLATION DAMPING DUE TO BEAM-BEAM COLLISIONS

    CERN Document Server

    Drago, A; Zobov, M; Shatilov, D

    2010-01-01

    In DAΦNE, the Frascati e+/e- collider, the crab waist collision scheme has been successfully implemented in 2008 and 2009. During the collision operations for Siddharta experiment, an unusual synchrotron damping effect has been observed. Indeed, with the longitudinal feedback switched off, the positron beam becomes unstable with beam currents in the order of 200-300 mA. The longitudinal instability is damped by bringing the positron beam in collision with a high current electron beam (~2A). Besides, we have observed a shift of ≈600Hz in the residual synchrotron sidebands. Precise measurements have been performed by using both a commercial spectrum analyzer and the diagnostics capabilities of the DAΦNE longitudinal bunch-by-bunch feedback. This damping effect has been observed in DAΦNE for the first time during collisions with the crab waist scheme. Our explanation is that beam collisions with a large crossing angle produce a longitudinal tune shift and a longitudinal tune spread, providing Landau damping...

  2. Synchrotron oscillation damping due to beam-beam collisions

    CERN Document Server

    Drago, A; Zobov, M; Shatilov, Dmitry

    2010-01-01

    In DA{\\Phi}NE, the Frascati e+/e- collider, the crab waist collision scheme has been successfully implemented in 2008 and 2009. During the collision operations for Siddharta experiment, an unusual synchrotron damping effect has been observed. Indeed, with the longitudinal feedback switched off, the positron beam becomes unstable with beam currents in the order of 200-300 mA. The longitudinal instability is damped by bringing the positron beam in collision with a high current electron beam (~2A). Besides, we have observed a shift of \\approx 600Hz in the residual synchrotron sidebands. Precise measurements have been performed by using both a commercial spectrum analyzer and the diagnostics capabilities of the DA{\\Phi}NE longitudinal bunch-by-bunch feedback. This damping effect has been observed in DA{\\Phi}NE for the first time during collisions with the crab waist scheme. Our explanation is that beam collisions with a large crossing angle produce a longitudinal tune shift and a longitudinal tune spread, providi...

  3. Simulation based analysis of laser beam brazing

    Science.gov (United States)

    Dobler, Michael; Wiethop, Philipp; Schmid, Daniel; Schmidt, Michael

    2016-03-01

    Laser beam brazing is a well-established joining technology in car body manufacturing with main applications in the joining of divided tailgates and the joining of roof and side panels. A key advantage of laser brazed joints is the seam's visual quality which satisfies highest requirements. However, the laser beam brazing process is very complex and process dynamics are only partially understood. In order to gain deeper knowledge of the laser beam brazing process, to determine optimal process parameters and to test process variants, a transient three-dimensional simulation model of laser beam brazing is developed. This model takes into account energy input, heat transfer as well as fluid and wetting dynamics that lead to the formation of the brazing seam. A validation of the simulation model is performed by metallographic analysis and thermocouple measurements for different parameter sets of the brazing process. These results show that the multi-physical simulation model not only can be used to gain insight into the laser brazing process but also offers the possibility of process optimization in industrial applications. The model's capabilities in determining optimal process parameters are exemplarily shown for the laser power. Small deviations in the energy input can affect the brazing results significantly. Therefore, the simulation model is used to analyze the effect of the lateral laser beam position on the energy input and the resulting brazing seam.

  4. Requirements of CLIC Beam Loss Monitoring System

    CERN Document Server

    Sapinski, M; Holzer, EB; Jonker, M; Mallows, S; Otto, T; Welsch, C

    2010-01-01

    The Compact Linear Collider (CLIC) [1] is a proposed multi-TeV linear electron-positron collider being designed by a world-wide collaboration. It is based on a novel twobeam acceleration scheme in which two beams (drive and main beam) are placed in parallel to each other and energy is transferred from the drive beam to the main one. Beam losses on either of them can have catastrophic consequences for the machine, because of high intensity (drive beam) or high energy and small emittance (main beam). In the framework of machine protection, a Beam Loss Monitoring (BLM) system has to be put in place. This paper discusses the requirements for the beam loss system in terms of detector sensitivity, resolution, dynamic range and ability to distinguish losses originating from various sources. The two-beam module where the protection from beam losses is particularly challenging and important, is studied.

  5. Induced focusing and conversion of a Gaussian beam into an elliptic Gaussian beam

    Indian Academy of Sciences (India)

    Manoj Mishra; Swapan Konar

    2005-09-01

    We have presented an investigation of the induced focusing in Kerr media of two laser beams, the pump beam and the probe beam, which could be either Gaussian or elliptic Gaussian or a combination of the two. We have used variational formalism to derive relevant beam-width equations. Among several important findings, the finding that a very week probe beam can be guided and focused when power of both beams are well below their individual threshold for self-focusing, is a noteworthy one. It has been found that induced focusing is not possible for laser beams of any wavelength and beam radius. In case both beams are elliptic Gaussian, we have shown that when power of both beams is above a certain threshold value then the effective radius of both beams collapses and collapse distance depends on power. Moreover, it has been found that induced focusing can be employed to convert a circular Gaussian beam into an elliptic Gaussian beam.

  6. Optimization Design and Application of Cantilever Roller in Walking-Beam Heating Furnace%炉内悬臂辊道的优化设计和应用

    Institute of Scientific and Technical Information of China (English)

    李君美; 杨威

    2013-01-01

    The structure of cantilever roller in walking-beam heating furnace is designed, and the application practice show that it improves the effect of the water cool, extends the service life, and reduces the costs.%对步进梁式加热炉内悬臂辊道的结构进行优化设计,应用实践表明,它提高了水冷效果,延长了使用寿命,降低了成本.

  7. Compact electron-beam source for formation of neutral beams of very low vapor pressure materials

    Science.gov (United States)

    Rutherford, J. A.; Vroom, D. A.

    1978-01-01

    In order to form metal vapors for neutral beam studies, an electron-beam heater and a power supply have been designed. The source, which measures about 30 x 50 x 70 mm, consists of a filament, accelerating plate (defined by pole pieces), and a supported target. The electrons from the filament are focused by the field penetration through a 2 mm slit in the high-voltage cage. They are then accelerated to about 5 kV to a ground plate. The electrons then follow a path in the magnetic field and strike the sample to be heated on its front surface. The assembly is attached to a water-cooled base plate. The electron beam source has produced beams of Ta and C particles with densities of about 10 to the 8th power/cu cm.

  8. Vertical Beam Size Measurement by Streak Camera under Colliding and Single Beam Conditions in KEKB

    CERN Document Server

    Ikeda, Hitomi; Fukuma, Hitoshi; Funakoshi, Yoshihiro; Hiramatsu, Shigenori; Mitsuhashi, Toshiyuki; Ohmi, Kazuhito; Uehara, Sadaharu

    2005-01-01

    Beam behavior of KEKB was studied by measurement of the beam size using a streak camera. Effect of the electron-cloud and the parasitic collision on the vertical beam size was examined in beam collision. We intentionally injected a test bunch of positrons after 2 rf buckets of a bunch to enhance the electron cloud effect and changed electron beam conditions to see the beam-beam effect. The beam size was also measured with a single positron beam and compared with that during collision. The result of the measurement is reported in this paper.

  9. Design of typical glued laminated timber beams

    OpenAIRE

    Domadenik, Žiga

    2015-01-01

    In this graduation thesis, I developed a computer program with the help of Excel's built-in developer. I used the programming language Visual Basics (VBA). The program allows dimensioning of typical laminated timber beams covered by Eurocode 5: Single tapered beam, double tapered beam, curved beam and pitched cambered beam. The program uses simplified expressions of Eurocode 5. The first part of the thesis describes expressions used for dimensioning, the second part describes the ...

  10. Fractal zone plate beam based optical tweezers

    Science.gov (United States)

    Cheng, Shubo; Zhang, Xinyu; Ma, Wenzhuo; Tao, Shaohua

    2016-01-01

    We demonstrate optical manipulation with an optical beam generated by a fractral zone plate (FZP). The experimental results show that the FZP beam can simultaneously trap multiple particles positioned in different focal planes of the FZP beam, owing to the multiple foci and self-reconstruction property of the FZP beam. The FZP beam can also be used to construct three-dimensional optical tweezers for potential applications. PMID:27678305

  11. MTN magnet for the SPS extracted beam.

    CERN Multimedia

    1976-01-01

    This type of dipole magnet was used in the extracted beam lines of the North Area. It shows an opening for three different proton beam lines: a primary extracted proton beam, split by an upstream magnetic beam splitter (see photo 7612017) into three separated beams passes through different parts of its aperture: right, left up, left down. These magnets were designed to be concrete-insulated for radiation resistance. F. Streun stands on the right.

  12. Gaussian-Beam Laser-Resonator Program

    Science.gov (United States)

    Cross, Patricia L.; Bair, Clayton H.; Barnes, Norman

    1989-01-01

    Gaussian Beam Laser Resonator Program models laser resonators by use of Gaussian-beam-propagation techniques. Used to determine radii of beams as functions of position in laser resonators. Algorithm used in program has three major components. First, ray-transfer matrix for laser resonator must be calculated. Next, initial parameters of beam calculated. Finally, propagation of beam through optical elements computed. Written in Microsoft FORTRAN (Version 4.01).

  13. Non-paraxial Elliptical Gaussian Beam

    Institute of Scientific and Technical Information of China (English)

    WANG Zhaoying; LIN Qiang; NI Jie

    2001-01-01

    By using the methods of Hertz vector and angular spectrum transormation, the exact solution of non-paraxial elliptical Gaussion beam with general astigmatism based on Maxwell′s equations is obtained. We discussed its propagation characteristics. The results show that the orientation of the elliptical beam spot changes continuously as the beam propagates through isotropic media. Splitting or coupling of beam spots may occur for different initial spot size. This is very different from that of paraxial elliptical Gaussian beam.

  14. Calibration of waveguide beam position monitors

    CERN Document Server

    Kamps, T

    2000-01-01

    To ensure overlap between the photon beam and electron beam at the SASE-FEL at the TESLA Test Facility, several position-sensitive diagnostics components are installed along the beamline of the FEL. For the undulator part, a new type of waveguide beam position monitors (BPMs) is designed, tested, and installed inside the beam pipe of one undulator module. This paper proposes a method to calibrate these monitors with beam-based measurements

  15. Laguerre-Gauss beams versus Bessel beams showdown: peer comparison.

    Science.gov (United States)

    Mendoza-Hernández, Job; Arroyo-Carrasco, Maximino Luis; Iturbe-Castillo, Marcelo David; Chávez-Cerda, Sabino

    2015-08-15

    We present for the first time a comparison under similar circumstances between Laguerre-Gauss beams (LGBs) and Bessel beams (BB), and show that the former can be a better option for many applications in which BBs are currently used. By solving the Laguerre-Gauss differential equation in the asymptotic limit of a large radial index, we find the parameters to perform a peer comparison, showing that LGBs can propagate quasi-nondiffracting beams within the same region of space where the corresponding BBs do. We also demonstrate that LGBs, which have the property of self-healing, are more robust in the sense that they can propagate further than BBs under similar initial conditions. PMID:26274648

  16. Beam Impedance Studies of the PS Beam Gas Ionization Monitor

    CERN Document Server

    Avgidis, Fotios

    2016-01-01

    The Beam Gas Ionization monitor (BGI) is a device for continuous beam size monitoring that is intended to be installed in the CERN Proton Synchrotron (PS) during the extended year-end technical stop from December 2016 to April 2017. With the objective of determining the impedance contribution of the BGI vacuum chamber to the overall beam impedance, we report on RF measurements on the device in a laboratory frame, measurement data analysis, and RF simulations of the structure under investigation. For the impedance contribution characterization of the BGI, the following approach has been followed: First, the EM fields inside a simplified BGI model that doesn’t include any of the internal components of the vacuum chamber have been simulated. RF measurements have been performed on the same empty structure showing great agreement between measurement and simulation and thus verifying the validity of the model. Second, simulations have been executed on a fully assembled BGI model that includes all the internal ele...

  17. Broad beam and narrow beam attenuation in Lipowitz's metal.

    Science.gov (United States)

    el-Khatib, E E; Podgorsak, E B; Pla, C

    1987-01-01

    Attenuation properties of Lipowitz's metal have been studied for narrow and broad beams of cobalt-60 gamma rays and 4-10 MV x-rays. The measured transmitted fraction for geometries used in radiotherapy depends on the field size and depth of measurement. Therefore a calculation of dose for partially attenuated beams based on narrow beam attenuation coefficients can cause large errors in dosimetry. Our simple calculation of transmitted fractions based on primary attenuation and scattered radiation agrees quite well with the measured data for therapeutic geometries. Also given is a table for linear, mass attenuation, and mass energy absorption coefficients of Lipowitz's metal in the photon energy range from 10 keV to 10 MeV. PMID:3104738

  18. Beam Measurements in Storage Rings

    Science.gov (United States)

    Hofmann, Albert

    1996-05-01

    Beam measurements in storage rings are made to diagnose performance limitations and to gain knowledge of the beam behavior in view of improvements and to the benefit for other machines. In beam optics the measurement of the orbit or the trajectory with beam position monitors distributed around the ring reveals deflection errors. The overall focusing is checked by measuring the betatron frequency (tune) using a pulse or continuous excitation of the oscillation. Observing this oscillation with all the beam position monitors around the ring the beta function and the betatron phase advance are obtained. This measurement done for different momenta, i.e. RF-frequencies, gives the local chromaticity and its correction. The tune dependence on quadrupole strength gives the value of the local beta function. Synchrotron radiation is a powerful diagnostics tool and can give the beam cross section. Beam instabilities are investigated with similar methods. The growth or damping rates and frequencies of betatron and synchrotron oscillations, observed as a function of intensity, give a convolution of the resistive and reactive part of the transverse and longitudinal impedance with the spectrum of the oscillation mode. Coupled bunch instabilities are caused by narrow band impedances at particular frequencies while single traversal effects, including energy loss and bunch lengthening, are due to a broad band impedance. A model of the impedance can be constructed from such measurements done with different bunch lengths, tunes and other parameters. In some cases the element causing an instability can be identified. The dependence of the orbit and phase advance around the ring on intensity can give the location of impedances. To probe the impedance at very high frequencies the effects on very short bunches or the energy loss of a continuous beam due to its Schottky noise are measured. The beam energy, usually known from magnetic measurements, can be obtained directly with high

  19. Electron beam ion source and electron beam ion trap (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Reinard [Scientific Software Service, Kapellenweg 2a, D-63571 Gelnhausen (Germany); Kester, Oliver [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States)

    2010-02-15

    The electron beam ion source (EBIS) and its trap variant [electron beam ion trap (EBIT)] celebrated their 40th and 20th anniversary, respectively, at the EBIS/T Symposium 2007 in Heidelberg. These technologically challenging sources of highly charged ions have seen a broad development in many countries over the last decades. In contrast to most other ion sources the recipe of improvement was not ''sorcery'' but a clear understanding of the physical laws and obeying the technological constraints. This review will report important achievements of the past as well as promising developments in the future.

  20. Nonlinear Localized Coherent Spectrum of Beam-Beam Interactions

    CERN Document Server

    Fedorova, A N; Fedorova, Antonina N.; Zeitlin, Michael G.

    2002-01-01

    We consider modeling for strong-strong beam-beam interactions beyond preceding linearized/perturbative methods such as soft gaussian approximation or FMM (HFMM) etc. In our approach discrete coherent modes, discovered before, and possible incoherent oscillations appear as a result of multiresolution/multiscale fast convergent decomposition in the bases of high-localized exact nonlinear modes represented by wavelets or wavelet packets functions. The constructed solutions represent the full multiscale spectrum in all internal hidden scales from slow to fast oscillating eigenmodes. Underlying variational method provides algebraical control of the spectrum.

  1. METHOD OF ELECTRON BEAM PROCESSING

    DEFF Research Database (Denmark)

    2003-01-01

    As a rule, electron beam welding takes place in a vacuum. However, this means that the workpieces in question have to be placed in a vacuum chamber and have to be removed therefrom after welding. This is time−consuming and a serious limitation of a process the greatest advantage of which is the o......As a rule, electron beam welding takes place in a vacuum. However, this means that the workpieces in question have to be placed in a vacuum chamber and have to be removed therefrom after welding. This is time−consuming and a serious limitation of a process the greatest advantage of which...... is the option of welding workpieces of large thicknesses. Therefore the idea is to guide the electron beam (2) to the workpiece via a hollow wire, said wire thereby acting as a prolongation of the vacuum chamber (4) down to workpiece. Thus, a workpiece need not be placed inside the vacuum chamber, thereby...... exploiting the potential of electron beam processing to a greater degree than previously possible, for example by means of electron beam welding...

  2. Low voltage electron beam accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ochi, Masafumi [Iwasaki Electric Co., Ltd., Tokyo (Japan)

    2003-02-01

    Widely used electron accelerators in industries are the electron beams with acceleration voltage at 300 kV or less. The typical examples are shown on manufactures in Japan, equipment configuration, operation, determination of process parameters, and basic maintenance requirement of the electron beam processors. New electron beam processors with acceleration voltage around 100 kV were introduced maintaining the relatively high dose speed capability of around 10,000 kGy x mpm at production by ESI (Energy Science Inc. USA, Iwasaki Electric Group). The application field like printing and coating for packaging requires treating thickness of 30 micron or less. It does not require high voltage over 110 kV. Also recently developed is a miniature bulb type electron beam tube with energy less than 60 kV. The new application area for this new electron beam tube is being searched. The drive force of this technology to spread in the industries would be further development of new application, process and market as well as the price reduction of the equipment, upon which further acknowledgement and acceptance of the technology to societies and industries would entirely depend. (Y. Tanaka)

  3. Triple ion beam irradiation facility

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, M.B.; Allen, W.R.; Buhl, R.A.; Packan, N.H.; Cook, S.W.; Mansur, L.K.

    1988-12-01

    A unique ion irradiation facility consisting of three accelerators is described. The accelerators can be operated simultaneously to deliver three ion beams on one target sample. The energy ranges of the ions are 50 to 400 keV, 200 keV to 2.5 MeV, and 1.0 to 5.0 MeV. Three different ions in the appropriate mass range can be simultaneously implanted to the same depth in a target specimen as large as 100 mm/sup 2/ in area. Typical depth ranges are 0.1 to 1.0 ..mu..m. The X-Y profiles of all three ion beams are measured by a system of miniature Faraday cups. The low-voltage accelerator can periodically ramp the ion beam energy during the implantation. Three different types of target chambers are in use at this facility. The triple-beam high-vacuum chamber can hold nine transmission electron microscopy specimens at elevated temperature during a irradiation by the three simultaneous beams. A second high-vacuum chamber on the medium-voltage accelerator beamline houses a low- and high-temperature translator and a two-axis goniometer for ion channeling measurements. The third chamber on the high-energy beamline can be gas-filled for special stressed specimen irradiations. Special applications for the surface modification of materials with this facility are described. Appendixes containing operating procedures are also included. 18 refs., 27 figs., 1 tab.

  4. Triple ion beam irradiation facility

    International Nuclear Information System (INIS)

    A unique ion irradiation facility consisting of three accelerators is described. The accelerators can be operated simultaneously to deliver three ion beams on one target sample. The energy ranges of the ions are 50 to 400 keV, 200 keV to 2.5 MeV, and 1.0 to 5.0 MeV. Three different ions in the appropriate mass range can be simultaneously implanted to the same depth in a target specimen as large as 100 mm2 in area. Typical depth ranges are 0.1 to 1.0 μm. The X-Y profiles of all three ion beams are measured by a system of miniature Faraday cups. The low-voltage accelerator can periodically ramp the ion beam energy during the implantation. Three different types of target chambers are in use at this facility. The triple-beam high-vacuum chamber can hold nine transmission electron microscopy specimens at elevated temperature during a irradiation by the three simultaneous beams. A second high-vacuum chamber on the medium-voltage accelerator beamline houses a low- and high-temperature translator and a two-axis goniometer for ion channeling measurements. The third chamber on the high-energy beamline can be gas-filled for special stressed specimen irradiations. Special applications for the surface modification of materials with this facility are described. Appendixes containing operating procedures are also included. 18 refs., 27 figs., 1 tab

  5. COMPASS measurements with hadron beams

    International Nuclear Information System (INIS)

    Muon and hadron beams from the CERN Super Proton Synchrotron are used in the COMPASS experiment for high-energy scattering reactions off fixed targets, aiming at measurements of non-perturbative aspects of quantum chromodynamics. With pion beams, the meson spectrum can be examined via diffractive dissociation, where the existence of hybrid or exotic states is a much discussed issue. The double-diffractive process of central production, which can be measured also with a proton beam, is a promising approach for the search for glueballs. At extremely small momentum transfer, electromagnetic processes are accessible via the Primakoff effect and aim at the determination of QCD low energy constants as the pion polarisability and the chiral anomaly. The muon program, focused on deep inelastic scattering, took place in the years 2002 to 2007. During this time, in autumn 2004, also a first pilot run with a pion beam was taken with the focus on diffractive and Primakoff measurements. Preliminary results and conclusions are presented. Data taking with a pion beam was resumed in 2008, where large statistics for diffractive scattering was collected. First insights, also in view of the findings of previous experiments, are presented, as well as the planning for continuation of data taking in 2009.

  6. Electron beam pumped semiconductor laser

    Science.gov (United States)

    Hug, William F. (Inventor); Reid, Ray D. (Inventor)

    2009-01-01

    Electron-beam-pumped semiconductor ultra-violet optical sources (ESUVOSs) are disclosed that use ballistic electron pumped wide bandgap semiconductor materials. The sources may produce incoherent radiation and take the form of electron-beam-pumped light emitting triodes (ELETs). The sources may produce coherent radiation and take the form of electron-beam-pumped laser triodes (ELTs). The ELTs may take the form of electron-beam-pumped vertical cavity surface emitting lasers (EVCSEL) or edge emitting electron-beam-pumped lasers (EEELs). The semiconductor medium may take the form of an aluminum gallium nitride alloy that has a mole fraction of aluminum selected to give a desired emission wavelength, diamond, or diamond-like carbon (DLC). The sources may be produced from discrete components that are assembled after their individual formation or they may be produced using batch MEMS-type or semiconductor-type processing techniques to build them up in a whole or partial monolithic manner, or combination thereof.

  7. Applications of electron lenses: scraping of high-power beams, beam-beam compensation, and nonlinear optics

    Energy Technology Data Exchange (ETDEWEB)

    Stancari, Giulio

    2014-09-11

    Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-by-bunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beam compensation, and for the demonstration of halo scraping with hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Hollow electron beam collimation and halo control were studied as an option to complement the collimation system for the upgrades of the Large Hadron Collider (LHC) at CERN; a conceptual design was recently completed. Because of their electric charge and the absence of materials close to the proton beam, electron lenses may also provide an alternative to wires for long-range beam-beam compensation in LHC luminosity upgrade scenarios with small crossing angles. At Fermilab, we are planning to install an electron lens in the Integrable Optics Test Accelerator (IOTA, a 40-m ring for 150-MeV electrons) as one of the proof-of-principle implementations of nonlinear integrable optics to achieve large tune spreads and more stable beams without loss of dynamic aperture.

  8. Processing of diamond by laser beam irradiation

    Science.gov (United States)

    Yoshikawa, Masanori; Hirata, Atsushi

    1998-10-01

    YAG and ArF excimer laser beams, of which wavelengths are 1.06 micrometers and 193 nm respectively, have been applied to processing of a variety of diamonds. Cutting and smoothing of natural, CVD and sintered diamonds have been performed. CVD diamond films were prepared by arc discharge plasma jet CVD and microwave plasma CVD, and sintered diamonds contain metallic or ceramic binder have been used. Fundamental removal processes of diamond with YAG and ArF excimer laser have been investigated using natural single crystal and CVD diamonds in various atmospheres changing laser irradiation conditions such as average power, energy density and pulse repetition rates. Cutting of natural and CVD diamonds with YAG laser proceeds at higher peal power that occurs at lower pulse repetition rates. Smooth surfaces are obtained by excimer laser irradiation at the incident angle of 80 percent. In the cases of the processing with YAG laser, the effect of local heating by laser beam irradiation mainly assists the diamond processing, and diamond appears to be removed after graphitization and oxidization following vaporization in the atmosphere contains oxygen. The temperature measurement was carried out at backside of irradiation surface, and increase of temperature when YAG laser beam was irradiated was larger than that when excimer laser was irradiated. On the contrary, the detection of C, C2, C+, O2 and CO from the emission at the irradiation area with ArF excimer laser beam suggest that processing partly proceeds by the separation of carbon atoms from the surface of diamond after braking bonds between carbon atoms caused by laser beam. Cutting of sintered diamond with metallic binder was difficult because metallic binder remains in the groove while ceramic binder was easily removed. Processing technique using laser beams has been applied to surface planing, chip preparation and edge formation of CVD diamond and curved surface formation on sintered diamond. Surface planing was

  9. Estimation of the Processing Parameters in Electron Beam Thermal Treatments

    Directory of Open Access Journals (Sweden)

    DULAU Mircea

    2014-05-01

    Full Text Available Electron beam have many special properties which make them particularly well suited for use in materials handling through melting, welding, surface treatment, etc., taking into account that this manufacturing is performed in vacuum. The use of electron beam for surface limited heat treatment of workpiece has brought about a noticeable extension of the beam technologies. Some theoretical aspects and simulation results are presented in this paper, considering a high power electron beam processing system and Matlab facilities. This paper can be used in power engineering and electro-technologies fields as a guideline, in order to simulate and analyse the process parameters.

  10. Physics Opportunities with Meson Beams

    CERN Document Server

    Briscoe, William J; Haberzettl, Helmut; Manley, D Mark; Naruki, Megumi; Strakovsky, Igor I; Swanson, Eric S

    2015-01-01

    Over the past two decades, meson photo- and electro-production data of unprecedented quality and quantity have been measured at electromagnetic facilities worldwide. By contrast, the meson-beam data for the same hadronic final states are mostly outdated and largely of poor quality, or even nonexistent, and thus provide inadequate input to help interpret, analyze, and exploit the full potential of the new electromagnetic data. To reap the full benefit of the high-precision electromagnetic data, new high-statistics data from measurements with meson beams, with good angle and energy coverage for a wide range of reactions, are critically needed to advance our knowledge in baryon and meson spectroscopy and other related areas of hadron physics. To address this situation, a state of-the-art meson-beam facility needs to be constructed. The present paper summarizes unresolved issues in hadron physics and outlines the vast opportunities and advances that only become possible with such a facility.

  11. Mycosis fungoides. Electron beam therapy.

    Science.gov (United States)

    Spittle, M F

    1977-01-01

    The most effective treatment of late mycosis fungoides is total skin electron beam therapy. The beam at the Hammersmith Hospital in London has been adapted to treat these patients. Patients with advanced disease who have failed more conservative methods of treatment are irradiated. The electron beam is modified by the use of carbon and copper scatterers to produce an 80 percent depth dose at 5.5, 8 and 11.5 millimeters below the skin surface. The dose achieved in most patients is between 1500 rads and 2600 rads given in 10 to 13 treatments over 5-7 weeks. Recently the higher dose range has been employed and lithium flouride studies have shown that giving these doses from each of 4 fields, the dose achieved on the skin is approximately twice the given dose. The management of patients and the effects of treatment are discussed.

  12. Preservation of beam loss induced quenches, beam lifetime and beam loss measurements with the HERAp beam-loss-monitor system

    Science.gov (United States)

    Wittenburg, Kay

    1994-06-01

    The beam-loss-monitors (BLMs) in the HERA-proton-ring (HERAp) must fulfill the following requirements: They have to measure losses sensitive and fast enough to prevent the superconducting magnets from beam loss induced quenching; the dynamic range of the monitors must exceed several decades in order to measure losses during beam lifetimes of hundreds of hours as well as the much stronger losses that may quench superconducting magnets; they have to be insensitive to the synchrotron radiation of the adjacent electron-ring (HERAe); and their radiation hardness must allow a monitor-lifetime of a few years of HERA operation. These requirements are well satisfied by the HERAp-BLM-System.

  13. Antiproton source beam position system

    International Nuclear Information System (INIS)

    The TeV I Beam Position Monitor (BPM) system is designed to provide a useful diagnostic tool during the commissioning and operational phases of the antiproton source. Simply stated the design goal is to provide single turn position information for intensities of > 1x109 particles, and multi-turn (clocked orbit) information for beam intensities of > 1x107 particles, both with sub-millimeter resolution. It is anticipated that the system will be used during commissioning for establishing the first turn through the Debuncher and Accumulator, for aligning injection orbits, for providing information necessary to correct closed orbits, and for measuring various machine parameters (e.g. tunes, dispersion, aperture, chromaticity). During normal antiproton operation the system will be used to monitor the beam position throughout the accumulation process

  14. Beam Cleaning and Collimation Systems

    CERN Document Server

    Redaelli, S

    2016-01-01

    Collimation systems in particle accelerators are designed to dispose of unavoidable losses safely and efficiently during beam operation. Different roles are required for different types of accelerator. The present state of the art in beam collimation is exemplified in high-intensity, high-energy superconducting hadron colliders, like the CERN Large Hadron Collider (LHC), where stored beam energies reach levels up to several orders of magnitude higher than the tiny energies required to quench cold magnets. Collimation systems are essential systems for the daily operation of these modern machines. In this document, the design of a multistage collimation system is reviewed, taking the LHC as an example case study. In this case, unprecedented cleaning performance has been achieved, together with a system complexity comparable to no other accelerator. Aspects related to collimator design and operational challenges of large collimation systems are also addressed.

  15. Effect of a brief post-weld heat treatment on the microstructure evolution and pitting corrosion of laser beam welded UNS S31803 duplex stainless steel

    International Nuclear Information System (INIS)

    Highlights: ► Pitting corrosion is investigated before and after post-weld heat treatment. ► The Cr2N precipitation is studied by SEM, TEM and AFM. ► The best short-time post-weld heat treatment condition is determined. ► The cause of pitting corrosion resistance variation is discussed in detail. - Abstract: The effect of laser-beam welding and subsequent short-time post-weld heat treatment at different temperatures and holding time on microstructure evolution and pitting corrosion behavior of UNS S31803 duplex stainless steel was investigated. The results showed the as-welded joint displayed impaired pitting corrosion resistance and that pitting preferentially occurred at ferrite grain in the fusion zone. Short-time heat treatment enhanced the pitting corrosion resistance of welded joint. Optimal post-weld heat treatment of 3 min heat treatment at 1080 °C was identified at which the joint restored the pitting corrosion resistance lost during welding process.

  16. Additional heat treatment of non-porous coatings obtained on medium carbon steel substrates by electron beam cladding of a Ti-Mo-C powder composition

    Science.gov (United States)

    Mul, D. O.; Drobyaz, E. A.; Zimoglyadova, T. A.; Bataev, V. A.; Lazurenko, D. V.; Shevtsova, L. I.

    2016-04-01

    The structure and microhardness of surface layers, obtained by non-vacuum electron beam cladding of Ti-Mo-C powder mixture on a steel substrate after different types of heat treatment, were investigated. After cladding samples were heat treated in a furnace at 200...500 °C, as well as quenched at 860 ° C and then underwent high-temperature tempering. Heat treatment of cladded coatings induced tempering of martensite and precipitation of cementite particles (Fe3C). Transmission electron microscopy of the samples after heating and holding at 300 ° C revealed precipitation of nanosized cubical TiC particles. The formation of hard nanosized particles led to the surface layer microhardness growth. The highest level of microhardness (which was 1.2...1.5-fold higher in comparison with coating microhardness after heat treatment) was achieved after heating of the claded material at 300 °C and 400 °C Additional quenching of samples at 860 °C did not increase the microhardness level.

  17. Status of Design of PEFP Beam Lines

    Energy Technology Data Exchange (ETDEWEB)

    Park, Bum Sik; Cho, Yong Sub; Kwon, Hyeok Jung; Jang, Ji Ho; Hong, In Seok; Kim, Han Sung; Yun, Sang Pil; Lee, Hwa Ryun; Kim, Kye Ryung; Choi, Byung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-10-15

    PEFP(Proton Engineering Frontier Project) is developing a high current 100MeV proton linear accelerator. 20MeV and 100MeV proton beam lines are also under development for beam applications. 10 beam lines will be developed to support various purposes. Two kind of proton beam energy will be transported to 2 beamlines for industrial applications and 3 beamlines for various researches. The characteristic design scheme of PEFP beam lines is the application of a programmable AC magnet. Beam distribution to 3 research beam lines will be conducted sequentially to increase the operation efficiency by using it. To provide flexibility of the irradiation conditions, each beam line is designed to have specific beam parameters. The development of beamline components, including magnets, is conducted in parallel. The details will be reported.

  18. Status of Design of PEFP Beam Lines

    International Nuclear Information System (INIS)

    PEFP(Proton Engineering Frontier Project) is developing a high current 100MeV proton linear accelerator. 20MeV and 100MeV proton beam lines are also under development for beam applications. 10 beam lines will be developed to support various purposes. Two kind of proton beam energy will be transported to 2 beamlines for industrial applications and 3 beamlines for various researches. The characteristic design scheme of PEFP beam lines is the application of a programmable AC magnet. Beam distribution to 3 research beam lines will be conducted sequentially to increase the operation efficiency by using it. To provide flexibility of the irradiation conditions, each beam line is designed to have specific beam parameters. The development of beamline components, including magnets, is conducted in parallel. The details will be reported

  19. Simulation and Experimental Studies on Composite Beams

    Directory of Open Access Journals (Sweden)

    M. Abhinay

    2014-09-01

    Full Text Available A composite beam a one dimensional structure or a rod all of them are sectional dimensions in which width and height are much smaller in comparison to the structure. In structural applications longer beams are more frequently used. In this work a composite beam is manufactured with glass and epoxy combination. And stress analysis is carried out using derived analytical expressions. This research work carried out will enable to determine the beam strength due to bending loads. The importance of fiber reinforcement in the manufacturing of the beam is studied in terms of bending strength of the beam. Mat lab codes are generated to implement analytical equations of the composite beam. The analytical results are validated by performing experiments on composite beams. In this investigation, two different composite beams have been tested and compared the experimental results with the analytical results.

  20. Development of proton beam monitoring devices

    International Nuclear Information System (INIS)

    We develop an 1 channel ionization chamber for beam monitoring system of KOMAC 20/100 MeV proton accelerator with a crystal scintillator, and try to make Multi Functional detectors, which can cover wide range of proton current. After the development, it is possible to provide the beam information to KOMAC beam users. We also develop a fast neutron detector system to detect the proton recoil by the neutron in the beam line. This system can provide the neutron dose information to beam user for safety. The followings are our major study 1) Beam profile and energy monitoring by using scintillators 2) Development of 32 channel Charge integration Embedded DAQ board 3) 1 channel gas scintillation detector for pulse beam monitoring 4) Development of fast neutron detector. Results Our major achievements are as follows ; 1) XY distribution scanning of proton beam by using LYSO crystal scintillator, 2) Development of a 32 channel Charge integration Embedded DAQ board and test it on beam line, 3) Development of 1 channel gas scintillation detector for pulse beam monitoring and test at KOMAC beam line. 4) Development of fast neutron detectors such as liquid scintillator and stilbene and measured neutron at beam line. The most important achievements of this research are ; 1) We measured the timing structure of proton beam by using 1 ch gas scintillation detector, and 2) it was possible to scanning the XY distribution of proton beam at real time