WorldWideScience

Sample records for high beam intensities

  1. High Intensity Secondary Beams Driven by Protons

    CERN Document Server

    Galambos, John; Nagaitsev, Sergei

    2013-01-01

    As part of the Intensity Frontier effort within the 2013 Community Summer Study, a workshop on the proton machine capabilities was held (High Intensity Secondary Beams Driven by Proton Beams) April 17-20, 2013 at Brookhaven National Laboratory in Upton, NY. Primary aims of the workshop were to understand: 1) the beam requirements for proposed high intensity proton beam based measurements; 2) the capabilities of existing world-wide high power proton machines; 3) proton facility upgrade plans and proposals for new facilities; 4) and to document the R&D needs for proton accelerators and target systems needed to support proposed intensity frontier measurements. These questions are addressed in this summary.

  2. Fermilab main injector: High intensity operation and beam loss control

    Science.gov (United States)

    Brown, Bruce C.; Adamson, Philip; Capista, David; Chou, Weiren; Kourbanis, Ioanis; Morris, Denton K.; Seiya, Kiyomi; Wu, Guan Hong; Yang, Ming-Jen

    2013-07-01

    From 2005 through 2012, the Fermilab Main Injector provided intense beams of 120 GeV protons to produce neutrino beams and antiprotons. Hardware improvements in conjunction with improved diagnostics allowed the system to reach sustained operation at 400 kW beam power. Transmission was very high except for beam lost at or near the 8 GeV injection energy where 95% beam transmission results in about 1.5 kW of beam loss. By minimizing and localizing loss, residual radiation levels fell while beam power was doubled. Lost beam was directed to either the collimation system or to the beam abort. Critical apertures were increased while improved instrumentation allowed optimal use of available apertures. We will summarize the improvements required to achieve high intensity, the impact of various loss control tools and the status and trends in residual radiation in the Main Injector.

  3. High intensity ion beams in rf undulator linac

    Directory of Open Access Journals (Sweden)

    E. S. Masunov

    2008-07-01

    Full Text Available The possibility of using a radio frequency undulator field to accelerate a high intensity ion beam in a linac is discussed. Such an accelerator can be realized using the periodical interdigital H-type resonator structure. The accelerating force is produced by an electric field which is a combination of two or more spatial harmonics, none of them being synchronous with the ion beam. The value of this force is proportional to the squared charge. The equations of motion in Hamiltonian form are derived by means of smooth approximation. The analysis of the 3D effective potential function allows finding the conditions of the beam focusing and acceleration. Two ways to increase ion beam intensity are considered: (i to enlarge beam cross section; (ii to neutralize the beam space charge by accelerating ions with opposite charge signs within the same bunch. The basic results are confirmed by a numerical simulation.

  4. A transparent vacuum window for high-intensity pulsed beams

    CERN Document Server

    Monteil, M; Veness, R

    2011-01-01

    The HiRadMat (High-Radiation to Materials) facility Ill will allow testing of accelerator components, in particular those of the Large Hadron Collider (LHC) at CERN, under the impact of high-intensity pulsed beams. To reach this intensity range, the beam will be focused on a focal point where the target to be tested is located. A 60 mm aperture vacuum window will separate the vacuum of the beam line which is kept under high vacuum 10(-8) mbar, from the test area which is at atmospheric pressure. This window has to resist collapse due to beam passage. The high-intensity of the beam means that typical materials used for standard vacuum windows (such as stainless steel, aluminium and titanium alloy) cannot endure the energy deposition induced by the beam passage. Therefore, a vacuum window has been designed to maintain the differential pressure whilst resisting collapse due to the beam impact on the window. In this paper, we will present calculations of the energy transfer from beam to window, the design of the ...

  5. Beam instrumentation for future high intense hadron accelerators at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, M.; Hu, M.; Tassotto, G.; Thurman-Keup, R.; Scarpine, V.; Shin, S.; Zagel, J.; /Fermilab

    2008-08-01

    High intensity hadron beams of up to 2 MW beam power are a key element of new proposed experimental facilities at Fermilab. Project X, which includes a SCRF 8 GeV H{sup -} linac, will be the centerpiece of future HEP activities in the neutrino sector. After a short overview of this, and other proposed projects, we present the current status of the beam instrumentation activities at Fermilab with a few examples. With upgrades and improvements they can meet the requirements of the new beam facilities, however design and development of new instruments is needed, as shown by the prototype and conceptual examples in the last section.

  6. Beam dynamics of mixed high intensity highly charged ion Beams in the Q/A selector

    Science.gov (United States)

    Zhang, X. H.; Yuan, Y. J.; Yin, X. J.; Qian, C.; Sun, L. T.; Du, H.; Li, Z. S.; Qiao, J.; Wang, K. D.; Zhao, H. W.; Xia, J. W.

    2017-06-01

    Electron cyclotron resonance (ECR) ion sources are widely used in heavy ion accelerators for their advantages in producing high quality intense beams of highly charged ions. However, it exists challenges in the design of the Q/A selection systems for mixed high intensity ion beams to reach sufficient Q/A resolution while controlling the beam emittance growth. Moreover, as the emittance of beam from ECR ion sources is coupled, the matching of phase space to post accelerator, for a wide range of ion beam species with different intensities, should be carefully studied. In this paper, the simulation and experimental results of the Q/A selection system at the LECR4 platform are shown. The formation of hollow cross section heavy ion beam at the end of the Q/A selector is revealed. A reasonable interpretation has been proposed, a modified design of the Q/A selection system has been committed for HIRFL-SSC linac injector. The features of the new design including beam simulations and experiment results are also presented.

  7. High Intensity Beam Issues in the CERN Proton Synchrotron

    CERN Document Server

    Aumon, Sandra; Rivkin, Leonid

    This PhD work is about limitations of high intensity proton beams observed in the CERN Proton Synchrotron (PS) and, in particular, about issues at injection and transition energies. With its 53 years, the CERN PS would have to operate beyond the limit of its performance to match the future requirements. Beam instabilities driven by transverse impedance and aperture restrictions are important issues for the operation and for the High-Luminosity LHC upgrade which foresees an intensity increase delivered by the injectors. The main subject of the thesis concerns the study of a fast transverse instability occurring at transition energy. The proton beams crossing this energy range are particularly sensitive to wake forces because of the slow synchrotron motion. This instability can cause a strong vertical emittance blow-up and severe losses in less than a synchrotron period. Experimental observations show that the particles at the peak density of the beam longitudinal distribution oscillate in the vertical plane du...

  8. Parallel Beam Dynamics Code Development for High Intensity Cyclotron

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>1 Parallel PIC algorithm Self field solver is the key part of a high intensity beam dynamic PIC code which usually adopts the P-M (Particle-Mesh) method to solve the space charge. The P-M method is composed of four major

  9. Investigations on transport and storage of high ion beam intensities

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Ninad Shrikrishna

    2009-08-25

    In the framework of this thesis the intense low energy ion beam transport was investigated. Especially, the beam transport in toroidal magnetic field configurations was discussed, as it may allow the accumulation of high intensive beams in the future. One of the specific tasks is to design an injection system that can be used for the proposed low energy accumulator ring. A simulation code (TBT) was written to describe the particle motion in curved segments. Particle in Cell techniques were utilized to simulate a multi particle dynamics. A possibility of reading an external data file was made available so that a measured distribution can be used to compare simulation results with measured ones. A second order cloud in cell method was used to calculate charge density and in turn to solve Poisson's equation. Further simulations were performed to study the self field effects on beam transport. Experiments were performed to compare the simulation results and gain practical experience. The preparatory experiments consisted of building and characterization of the ion source in a first step. Along with the momentum spectrometer and emittance scanner the beam properties were studied. Low mass ion beams He{sup +} and mixed p, H{sup 2+}, H{sup 3+} beams were analyzed. In the second stage, beams were transported through a solenoid and the phase space distribution was measured as a function of the magnetic field for different beam energies. The phase-space as distributions measured in a first stage were simulated backward and then again forward transported through the solenoid. The simulated results were then compared with the measured distribution. The LINTRA transport program was used. The phase-space distribution was further simulated for transport experiments in a toroidal magnetic field. The transport program that was used to simulate the beam in the toroid was also used to design the injection system. The injection system with its special field configurations was

  10. Development of High Intensity Beam Emittance Measurement Unit

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Three sets of High Intensity Beam Emittance Measurement Units (HIBEMUs) are being developed at Peking University. They are HIBEMU-2 (slit-wire type, one direction), HIBEMU-3 (Allison scanner type, one direction) and HIBEMU-4 (slit-wire type, two directions). For HIBEMU-2 and HIBEMU-3, more recent work has been done on software redesign in order to measure beam emittance and to draw phase diagram more efficiently and precisely. Software for control and data processing of them were developed in Labveiw environment, trying to improve calculation rationality and to offer user-friendly interface. Mechanical modification was also done for HIBEMU-3, mainly concentrating on the protection of Faraday cups from being overheated by the high intensity beam and also from interference of secondary electrons. This paper will also cover the mechanical structure as well as the software development of HIBEMU-4, which is a two-direction emittance scanner newly designed and manufactured for the high energy beam transport (HEBT) of Peking University Neutron Imaging FaciliTY (PKUNIFTY). At the end of this paper, comparison and analysis of the three HIBEMUs are given to draw forth better design of the future emittance measurement facility.

  11. The generation of high-quality, intense ion beams by ultra-intense lasers

    CERN Document Server

    Roth, M; Audebert, Patrick; Blazevic, A; Brambrink, E; Cowan, T E; Fuchs, J; Gauthier, J C; Geissel, M; Hegelich, M; Karsch, S; Meyer-Ter-Vehn, J; Ruhl, H; Schlegel, T; Stephens, R B

    2002-01-01

    Intense beams of protons and heavy ions have been observed in ultra-intense laser-solid interaction experiments. Thereby, a considerable fraction of the laser energy is transferred to collimated beams of energetic ions (e.g. up to 50 MeV protons; 100 MeV fluorine), which makes these beams highly interesting for various applications. Experimental results indicate a very short-pulse duration and an excellent beam quality, leading to beam intensities in the TW range. To characterize the beam quality and its dependence on laser parameters and target conditions we performed experiments using the 100 TW laser system at Laboratoire pour l'Utilisation des Lasers Intenses at the Ecole Polytechnique, France, with focused intensities exceeding 10 sup 1 sup 9 W cm sup - sup 2. We found a strong dependence on the target rear surface conditions allowing to tailor the ion beam by an appropriate target design. We also succeeded in the generation of heavy ion beams by suppressing the proton amount at the target surface. We wi...

  12. Bunching high intensity proton beams with a CH-DTL

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Malte; Claessens, Christine; Heilmann, Manuel; Hinrichs, Ole; Koser, Daniel; Meusel, Oliver; Noll, Daniel; Podlech, Holger; Ratzinger, Ulrich; Seibel, Anja [Institut fuer Angewandte Physik, Goethe-Universitaet Frankfurt am Main (Germany)

    2014-07-01

    The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) will provide ultra short neutron pulses at high intensities and repetition rates. The facility is under construction with an expected first beam by the end of 2014. A 5-Gap CH rebuncher is installed behind a coupled RFQ/IH-DTL combination at the end of the LINAC section between two magnetic quadrupole triplets. It will be used for varying the final energy between 1.8 and 2.2 MeV, as well as for focusing the proton beam bunch longitudinally, to compensate RF defocusing effects and huge space charge forces at currents up to 200 mA at the final stage of extension. Therefore high current beam dynamic simulations are in progress. They include benchmarking of different beam dynamic codes like LORASR, TraceWin and Bender (a new PIC tracking code developed at IAP), as well as validating the results by measurements. Detailed error tolerance studies, thermal simulations and examination of multipole field impact, due to the cavity geometry, are also done. Furthermore, this CH rebuncher serves as prototype for CH cavity operation at MYRRHA (Belgium), an Accelerator Driven System (ADS) for transmutation of high level nuclear waste. After copper-plating the cavity, RF conditioning will start in spring 2014.

  13. Fast damping in mismatched high intensity beam transportation

    Directory of Open Access Journals (Sweden)

    V. Variale

    2001-08-01

    Full Text Available A very fast damping of beam envelope oscillation amplitudes was recently observed in simulations of high intensity beam transport, through periodic FODO cells, in mismatched conditions [V. Variale, Nuovo Cimento Soc. Ital. Fis. 112A, 1571–1582 (1999 and T. Clauser et al., in Proceedings of the Particle Accelerator Conference, New York, 1999 (IEEE, Piscataway, NJ, 1999, p. 1779]. A Landau damping mechanism was proposed at the origin of observed effect. In this paper, to further investigate the source of this fast damping, extensive simulations have been carried out. The results presented here support the interpretation of the mechanism at the origin of the fast damping as a Landau damping effect.

  14. FNAL Proton Source High Intensity Operations and Beam Loss Control

    CERN Document Server

    Garcia, F G

    2014-01-01

    The 40-year-old Fermilab Proton Source machines, constituted by the Pre-Injector, Linac and the synchrotron Booster, have been the workhorse of the Fermi National Accelerator Laboratory (Fermilab). During this time, the High Energy Physics Program has demanded an increase in proton throughput, especially during the past decade with the beginning of the neutrino program at Fermilab. In order to achieve a successful program, major upgrades and changes were made in Booster. Once again, the Proton Source has been charged to double their beam throughput, while maintain the present residual activation levels, to meet the laboratory Intensity Frontier program goals until new machines are built and operational to replace the Proton Source machines. This paper discusses the present performance of Booster and the plans involved in reaching even higher intensities.

  15. Energy gain and spectral tailoring of ion beams using ultra-high intensity laser beams

    Science.gov (United States)

    Prasad, Rajendra; Swantusch, Marco; Cerchez, Mirela; Spickermann, Sven; Auorand, Bastian; Wowra, Thomas; Boeker, Juergen; Willi, Oswald

    2015-11-01

    The field of laser driven ion acceleration over the past decade has produced a huge amount of research. Nowadays, several multi-beam facilities with high rep rate system, e.g. ELI, are being developed across the world for different kinds of experiments. The study of interaction dynamics of multiple beams possessing ultra-high intensity and ultra-short pulse duration is of vital importance. Here, we present the first experimental results on ion acceleration using two ultra-high intensity beams. Thanks to the unique capability of Arcturus laser at HHU Düsseldorf, two almost identical, independent beams in laser parameters such as intensity (>1020 W/cm2), pulse duration (30 fs) and contrast (>1010), could be accessed. Both beams are focused onto a 5 μm thin Ti target. While ensuring spatial overlap of the two beams, at relative temporal delay of ~ 50 ps (optimum delay), the proton and carbon ion energies were enhanced by factor of 1.5. Moreover, strong modulation in C4+ions near the high energy cut-off is observed later than the optimum delay for the proton enhancement. This offers controlled tailoring of the spectral content of heavy ions.

  16. Beam Dynamics Studies for High-Intensity Beams in the CERN Proton Synchrotron

    CERN Document Server

    AUTHOR|(CDS)2082016; Benedikt, Michael

    With the discovery of the Higgs boson, the existence of the last missing piece of the Standard Model of particle physics (SM) was confirmed. However, even though very elegant, this theory is unable to explain, for example, the generation of neutrino masses, nor does it account for dark energy or dark matter. To shed light on some of these open questions, research in fundamental particle physics pursues two complimentary approaches. On the one hand, particle colliders working at the high-energy frontier, such as the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN), located in Geneva, Switzerland, are utilized to investigate the fundamental laws of nature. Alternatively, fixed target facilities require high-intensity beams to create a large flux of secondary particles to investigate, for example, rare particle decay processes, or to create neutrino beams. This thesis investigates limitations arising during the acceleration of high-intensity beams at the CERN Proton Synchrotro...

  17. Ionization Chambers for Monitoring in High-Intensity Neutrino Beams

    CERN Document Server

    McDonald, J; Velissaris, C; Erwin, A R; Ping, H; Viren, B M; Diwan, M V

    2002-01-01

    Radiation-hard ionization chambers were tested using an intense electron beam from the accelerator test facility (ATF) at the Brookhaven National Laboratory (BNL). The detectors were designed to be used as the basic element for monitoring muons in the Main Injector Neutrino beamline (NuMI) at the Fermi National Accelerator Laboratory (FNAL). Measurements of linearity of response, voltage dependence, and the onset of ionization saturation as a function of gap voltage were performed.

  18. Intense high-quality medical proton beams via laser fields

    CERN Document Server

    Galow, Benjamin J; Keitel, Christoph H

    2010-01-01

    Simulations based on the coupled relativistic equations of motion show that protons stemming from laserplasma processes can be efficiently post-accelerated employing crossed pulsed laser beams focused to spot radii on the order of the laser wavelength. We demonstrate that the crossed beams produce quasi-monoenergetic accelerated protons with kinetic energies exceeding 200 MeV, small energy spreads of about 1% and high densities as required for hadron cancer therapy.

  19. Study of a final focus system for high intensity beams

    Energy Technology Data Exchange (ETDEWEB)

    Henestroza, Enrique; Eylon, Shmuel; Roy, Prabir K.; Yu, Simon S.; Bieniosek, Frank M.; Shuman, Derek B.; Waldron, William L.

    2004-06-01

    The NTX experiment at the Heavy Ion Fusion Virtual National Laboratory is exploring the performance of neutralized final focus systems for high perveance heavy ion beams. The final focus scenario in an HIF driver consists of several large aperture quadrupole magnets followed by a drift section in which the beam space charge is neutralized by a plasma. This beam is required to hit a millimeter-sized target spot at the end of the drift section. The objective of the NTX experiments and associated theory and simulations is to study the various physical mechanisms that determine the final spot size (radius r{sub s}) at a given distance (f) from the end of the last quadrupole. In a fusion driver, f is the standoff distance required to keep the chamber wall and superconducting magnets properly protected. The NTX final quadrupole focusing system produces a converging beam at the entrance to the neutralized drift section where it focuses to a small spot. The final spot is determined by the conditions of the beam entering the quadrupole section, the beam dynamics in the magnetic lattice, and the plasma neutralization dynamics in the drift section. The main issues are the control of emittance growth due to high order fields from magnetic multipoles and image fields. In this paper, we will describe the theoretical and experimental aspects of the beam dynamics in the quadrupole lattice, and how these physical effects influence the final beam size. In particular, we present theoretical and experimental results on the dependence of final spot size on geometric aberrations and perveance.

  20. A 3 GHz photoelectron gun for high beam intensity

    CERN Document Server

    Bossart, Rudolf; Dehler, M; Godot, J C

    1996-01-01

    For the Compact Linear Collider Test Facility (CTF) at CERN a new rf gun with a laser driven photocathode is under construction. The new rf gun will replace the present 11/2 cell gun and will consist of 21/2 cells accelerating the beam to a momentum of 7.0 MeV/c with an electric field strength of 100 MV/m. The strong space-charge forces at low beam energy caused by the high charge density of the electron bunches are contained by radial and longitudinal rf focusing in the gun. The rf gun under construction has been optimized by MAFIA beam simulations for an injector assembly comprising a second accelerating rf structure and an intermediate solenoid magnet correcting the beam divergence of the 21/2 cell gun. The beam loading of the rf gun, by a train of 48 bunches with 21 nC charge each, causes a strong energy decay accompanied by an increase of the flight time for the bunches with lower energy. These effects can be corrected by slightly shifting the acceleration frequency of the gun. The experimental results...

  1. The Fermilab Main Injector: high intensity operation and beam loss control

    CERN Document Server

    Brown, Bruce C; Capista, David; Chou, Weiren; Kourbanis, Ioanis; Morris, Denton K; Seiya, Kiyomi; Wu, Guan Hong; Yang, Ming-Jen

    2013-01-01

    From 2005 through 2012, the Fermilab Main Injector provided intense beams of 120 GeV protons to produce neutrino beams and antiprotons. Hardware improvements in conjunction with improved diagnostics allowed the system to reach sustained operation at ~400 kW beam power. Transmission was very high except for beam lost at or near the 8 GeV injection energy where 95% beam transmission results in about 1.5 kW of beam loss. By minimizing and localizing loss, residual radiation levels fell while beam power was doubled. Lost beam was directed to either the collimation system or to the beam abort. Critical apertures were increased while improved instrumentation allowed optimal use of available apertures. We will summarize the improvements required to achieve high intensity, the impact of various loss control tools and the status and trends in residual radiation in the Main Injector.

  2. STATUS REPORT ON DEVELOPMENT OF A HIGH-SPEED HIGH-INTENSITY MOLECULAR BEAM

    Energy Technology Data Exchange (ETDEWEB)

    Knuth, Eldon L.

    1963-07-15

    Status of a high-speed high-intensity molecular beam under development is described. Bases for designs of the several components are presented. Using an arc-heated source and a hypersonic jet, molecular energies exceeding 1 ev and beam intensities of the order of 10/sup 16/ molecules/ cm/sup 2/ sec are anticipated. A two-disk beam chopper and speed selector provides a means for analyzing the speed distribution in the generated beam, for chopping the beam into bursts of nearly monoenergetic molecules suitable for scattering studies using the time-of-flight technique, and for modulating the beam in order to facilitate detection. A through-flow ionization detector possesses the versatility required for scattering studies using the time-of-flight technique. A sorption pump and a turbo pump serve as central components of alternative pumping systems for the collimating chamber. Using the arc-heated source, the converging nozzle, the conduction-radiation-cooled skimmer, the turbo pump (turning at 3400 rpm), the chopperselector (acting only as a chopper), and the detector, an arc-heated beam is generated and detected. (auth)

  3. Beam Dynamics Observations of the 2015 High Intensity Scrubbing Runs at the Cern Sps

    CERN Document Server

    Bartosik, Hannes; Li, Kevin; Mether, Lotta; Romano, Annalisa; Rumolo, Giovanni; Schenk, Michael

    2016-01-01

    Beam quality degradation caused by e-cloud effects has been identified as one of the main performance limitations for high intensity LHC beams with 25 ns bunch spacing in the SPS. In view of the beam parameters targeted with the LHC injectors upgrade (LIU) project, about two weeks of SPS machine time in 2015 were devoted to dedicated scrubbing runs with high intensity LHC 25 ns and dedicated 'doublet' beams in order to study the achievable reduction of e-cloud effects and quantify the consequent beam performance improvements. This paper describes the main observations concerning the coherent instabilities and beam dynamics limitations encountered as well as a detailed characterisation of the performance reach with the highest beam intensity presently available from the pre-injectors.

  4. Protection and Diagnostic Systems for High Intensity Beams

    CERN Document Server

    Jensen, L; Vismara, Giuseppe

    2000-01-01

    This paper presents a summary of the facilities for beam interlocks and diagnostics to protect the CERN SPS machine. An overview of the existing systems is given, which are based on beam loss and beam current monitors and large beam position excursion in the horizontal plane. The later system mainly protects the system against a failure of the transverse damping system. The design for a new large excursion interlock for both transverse planes is also presented in some detail. For this system a digital approach is being taken to allow post-mortem analysis of the behaviour of the beam prior to the activation of the interlock.

  5. Examination of Beryllium Under Intense High Energy Proton Beam at CERN's HiRadMat Facility

    CERN Document Server

    Ammigan, K; Hurh, P; Zwaska, R; Atherton, A; Caretta, O; Davenne, t; Densham, C; Fitton, M; Loveridge, P; O'Dell, J; Roberts, S; Kuksenko, v; Butcher, M; Calviani, M; Guinchard, M; Losito, R

    2015-01-01

    Beryllium is extensively used in various accelerator beam lines and target facilities as material for beam win- dows, and to a lesser extent, as secondary particle produc- tion targets. With increasing beam intensities of future ac- celerator facilities, it is critical to understand the response of beryllium under extreme conditions to avoid compro- mising particle production efficiency by limiting beam pa- rameters. As a result, the planned experiment at CERN’s HiRadMat facility will take advantage of the test facility’s tunable high intensity proton beam to probe and investigate the damage mechanisms of several grades of beryllium. The test matrix will consist of multiple arrays of thin discs of varying thicknesses as well as cylinders, each exposed to increasing beam intensities. Online instrumentations will acquire real time temperature, strain, and vibration data of the cylinders, while Post-Irradiation-Examination (PIE) of the discs will exploit advanced microstructural characteri- zation and imagin...

  6. Examination of Beryllium Under Intense High Energy Proton Beam at CERN's HiRadMat Facility

    CERN Document Server

    Ammigan, K.; Hurh, P.; Zwaska, R.; Atherton, A.; Caretta, O.; Davenne,T.; Densham, C.; Fitton, M.; Loveridge, P.; O'Dell, J.; Roberts, S.; Kuksenko, V.; Butcher, M.; Calviani, M.; Guinchard, M.; Losito, R.

    2017-01-01

    Beryllium is extensively used in various accelerator beam lines and target facilities as material for beam win- dows, and to a lesser extent, as secondary particle produc- tion targets. With increasing beam intensities of future ac- celerator facilities, it is critical to understand the response of beryllium under extreme conditions to avoid compro- mising particle production efficiency by limiting beam pa- rameters. As a result, the planned experiment at CERN’s HiRadMat facility will take advantage of the test facility’s tunable high intensity proton beam to probe and investigate the damage mechanisms of several grades of beryllium. The test matrix will consist of multiple arrays of thin discs of varying thicknesses as well as cylinders, each exposed to increasing beam intensities. Online instrumentations will acquire real time temperature, strain, and vibration data of the cylinders, while Post-Irradiation-Examination (PIE) of the discs will exploit advanced microstructural characteri- zation and imagin...

  7. High performance computation on beam dynamics problems in high intensity compact cyclotrons

    Institute of Scientific and Technical Information of China (English)

    ADELMANN; Andreas

    2011-01-01

    This paper presents the research progress in the beam dynamics problems for future high intensity compact cyclotrons by utilizing the state-of-the-art high performance computation technology. A "Start-to-Stop" model, which includes both the interaction of the internal particles of a single bunch and the mutual interaction of neighboring multiple bunches in the radial direction, is established for compact cyclotrons with multi-turn extraction. This model is then implemented in OPAL-CYCL, which is a 3D object-oriented parallel code for large scale particle simulations in cyclotrons. In addition, to meet the running requirement of parallel computation, we have constructed a small scale HPC cluster system and tested its performance. Finally, the high intensity beam dynamics problems in the 100 MeV compact cyclotron, which is being constructed at CIAE, are studied using this code and some conclusions are drawn.

  8. Transverse Beam Halo Measurements at High Intensity Neutrino Source (HINS) using Vibrating Wire Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Chung, M.; Hanna, B.; Scarpine, V.; Shiltsev, V.; Steimel, J.; Artinian, S.; Arutunian, S.

    2015-02-26

    The measurement and control of beam halos will be critical for the applications of future high-intensity hadron linacs. In particular, beam profile monitors require a very high dynamic range when used for the transverse beam halo measurements. In this study, the Vibrating Wire Monitor (VWM) with aperture 60 mm was installed at the High Intensity Neutrino Source (HINS) front-end to measure the transverse beam halo. A vibrating wire is excited at its resonance frequency with the help of a magnetic feedback loop, and the vibrating and sensitive wires are connected through a balanced arm. The sensitive wire is moved into the beam halo region by a stepper motor controlled translational stage. We study the feasibility of the vibrating wire for the transverse beam halo measurements in the low-energy front-end of the proton linac.

  9. Generalized Kapchinskij-Vladimirskij Distribution and Beam Matrix for Phase-Space Manipulations of High-Intensity Beams

    CERN Document Server

    Chung, Moses; Davidson, Ronald C; Groening, Lars; Xiao, Chen

    2016-01-01

    In an uncoupled linear lattice system, the Kapchinskij-Vladimirskij (KV) distribution, formulated on the basis of the single-particle Courant-Snyder (CS) invariants, has served as a fundamental theoretical basis for the analyses of the equilibrium, stability, and transport properties of high-intensity beams for the past several decades. Recent applications of high-intensity beams, however, require beam phase-space manipulations by intentionally introducing strong coupling. In this Letter, we report the full generalization of the KV model by including all of the linear (both external and space-charge) coupling forces, beam energy variations, and arbitrary emittance partition, which all form essential elements for phase-space manipulations. The new generalized KV model yields spatially uniform density profiles and corresponding linear self-field forces as desired. The corresponding matrix envelope equations and beam matrix for the generalized KV model provide important new theoretical tools for the detailed des...

  10. Selected List of Low Energy Beam Transport Facilities for Light-Ion, High-Intensity Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Prost, L. R. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)

    2016-02-17

    This paper presents a list of Low Energy Beam Transport (LEBT) facilities for light-ion, high-intensity accelerators. It was put together to facilitate comparisons with the PXIE LEBT design choices. A short discussion regarding the importance of the beam perveance in the choice of the transport scheme follows.

  11. High intensity proton beam transportation through fringe field of 70 MeV compact cyclotron to beam line targets

    Science.gov (United States)

    Zhang, Xu; Li, Ming; Wei, Sumin; Xing, Jiansheng; Hu, Yueming; Johnson, Richard R.; Piazza, Leandro; Ryjkov, Vladimir

    2016-06-01

    From the stripping points, the high intensity proton beam of a compact cyclotron travels through the fringe field area of the machine to the combination magnet. Starting from there the beams with various energy is transferred to the switching magnet for distribution to the beam line targets. In the design of the extraction and transport system for the compact proton cyclotron facilities, such as the 70 MeV in France and the 100 MeV in China, the space charge effect as the beam crosses the fringe field has not been previously considered; neither has the impact on transverse beam envelope coupled from the longitudinal direction. Those have been concerned much more with the higher beam-power because of the beam loss problem. In this paper, based on the mapping data of 70 MeV cyclotron including the fringe field by BEST Cyclotron Inc (BEST) and combination magnet field by China Institute of Atomic Energy (CIAE), the beam extraction and transport are investigated for the 70 MeV cyclotron used on the SPES project at Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro (INFN-LNL). The study includes the space charge effect and longitudinal and transverse coupling mentioned above, as well as the matching of beam optics using the beam line for medical isotope production as an example. In addition, the designs of the ±45° switching magnets and the 60° bending magnet for the extracted beam with the energy from 35 MeV to 70 MeV have been made. Parts of the construction and field measurements of those magnets have been done as well. The current result shows that, the design considers the complexity of the compact cyclotron extraction area and fits the requirements of the extraction and transport for high intensity proton beam, especially at mA intensity levels.

  12. High intensity proton beam transportation through fringe field of 70 MeV compact cyclotron to beam line targets

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xu, E-mail: emmazhang103@gmail.com [China Institute of Atomic Energy (China); Li, Ming; Wei, Sumin; Xing, Jiansheng; Hu, Yueming [China Institute of Atomic Energy (China); Johnson, Richard R.; Piazza, Leandro; Ryjkov, Vladimir [BEST Cyclotron Inc (Canada)

    2016-06-01

    From the stripping points, the high intensity proton beam of a compact cyclotron travels through the fringe field area of the machine to the combination magnet. Starting from there the beams with various energy is transferred to the switching magnet for distribution to the beam line targets. In the design of the extraction and transport system for the compact proton cyclotron facilities, such as the 70 MeV in France and the 100 MeV in China, the space charge effect as the beam crosses the fringe field has not been previously considered; neither has the impact on transverse beam envelope coupled from the longitudinal direction. Those have been concerned much more with the higher beam-power because of the beam loss problem. In this paper, based on the mapping data of 70 MeV cyclotron including the fringe field by BEST Cyclotron Inc (BEST) and combination magnet field by China Institute of Atomic Energy (CIAE), the beam extraction and transport are investigated for the 70 MeV cyclotron used on the SPES project at Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro (INFN–LNL). The study includes the space charge effect and longitudinal and transverse coupling mentioned above, as well as the matching of beam optics using the beam line for medical isotope production as an example. In addition, the designs of the ±45° switching magnets and the 60° bending magnet for the extracted beam with the energy from 35 MeV to 70 MeV have been made. Parts of the construction and field measurements of those magnets have been done as well. The current result shows that, the design considers the complexity of the compact cyclotron extraction area and fits the requirements of the extraction and transport for high intensity proton beam, especially at mA intensity levels.

  13. Proton Drivers for neutrino beams and other high intensity applications

    CERN Document Server

    Garoby, R; Koseki, T; Thomason, J

    2013-01-01

    CERN, Fermilab, J-PARC and RAL tentatively plan to have proton accelerators delivering multi-MW of beam power in view of enhancing their physics reach especially in the domain of neutrinos. These plans are described, together with their benefits for other applications.

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

    CERN Document Server

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

    2005-01-01

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

  15. Dynamics of cavitation clouds within a high-intensity focused ultrasonic beam

    NARCIS (Netherlands)

    Lu, Yuan; Katz, Joseph; Prosperetti, Andrea

    2013-01-01

    In this experimental study, we generate a 500 kHz high-intensity focused ultrasonic beam, with pressure amplitude in the focal zone of up to 1.9 MPa, in initially quiescent water. The resulting pressure field and behavior of the cavitation bubbles are measured using high-speed digital in-line hologr

  16. Low level RF systems for synchrotrons part II: High Intensity. Compensation of the beam induced effects

    CERN Document Server

    Baudrenghien, P

    2005-01-01

    The high intensity regime is reached when the voltage induced by the beam in the RF cavities is of an amplitude comparable to the desired accelerating voltage. In steady state this beam loading can be compensated by providing extra RF power. Transient beam loading occurs at injection or in the presence of a beam intensity that is not uniform around the ring. The transients are periodic at the revolution frequency. Without correction transient beam loading can be very harmful: The stable phase and bucket area will not be equal for all bunches. Strong beam loading often goes in pair with longitudinal instabilities because the RF cavities are a large contributor to the total ring impedance. The low level systems that reduce the effect of the transient beam loading will also increase the threshold intensity of the longitudinal instability caused by the cavity impedance at the fundamental RF frequency. Four classic methods are presented here: Feedforward, RF feedback, long delay feedback and bunch by bunch feedbac...

  17. Intial characterization fo a commerical electron gun for profiling high intensity proton beams in Project X

    Energy Technology Data Exchange (ETDEWEB)

    Thurman-Keup, R.; Johnson, A.S.; Lumpkin, A.H.; Thangaraj, J.C.T.; Zhang, D.; /Fermilab; Blokland, W.; /Oak Ridge

    2011-03-01

    Measuring the profile of a high-intensity proton beam is problematic in that traditional invasive techniques such as flying wires don't survive the encounter with the beam. One alternative is the use of an electron beam as a probe of the charge distribution in the proton beam as was done at the Spallation Neutron Source at ORNL. Here we present an initial characterization of the beam from a commercial electron gun from Kimball Physics, intended for use in the Fermilab Main Injector for Project X. Despite the fact that the horizontal spot size is abnormally large in the high current measurement, the spot size at the downstream cross X2 is reasonable in the context of measuring the deflection. A thin foil OTR would help with the beam heating and should be tried. The next phase of this experiment is to simulate the proton beam with a pair of current carrying wires and to design and construct a fast deflector. Some of the remaining issues to be considered include determining the minimum beam current needed to observe the deflected beam for a given sweep time and the impact of longitudinal variations in the charge density of the bunch.

  18. A focusable, convergent fast-electron beam from ultra-high-intensity laser-solid interactions

    CERN Document Server

    Scott, R H H

    2015-01-01

    A novel scheme for the creation of a convergent, or focussing, fast-electron beam generated from ultra-high-intensity laser-solid interactions is described. Self-consistent particle-in-cell simulations are used to demonstrate the efficacy of this scheme in two dimensions. It is shown that a beam of fast-electrons of energy 500 keV - 3 MeV propagates within a solid-density plasma, focussing at depth. The depth of focus of the fast-electron beam is controlled via the target dimensions and focussing optics.

  19. A mask for high-intensity heavy-ion beams in the MAYA active target

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez-Tajes, C., E-mail: rodriguez@ganil.fr [Grand Accélérateur National d' Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, Bvd Henri Becquerel, 14076 Caen (France); Universidade de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Pancin, J.; Damoy, S.; Roger, T.; Babo, M. [Grand Accélérateur National d' Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, Bvd Henri Becquerel, 14076 Caen (France); Caamaño, M. [Universidade de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Farget, F.; Grinyer, G.F.; Jacquot, B.; Pérez-Loureiro, D. [Grand Accélérateur National d' Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, Bvd Henri Becquerel, 14076 Caen (France); Ramos, D. [Universidade de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Suzuki, D. [Institut de Physique Nucléaire, Université Paris-Sud 11, CNRS/IN2P3, F-91406 Orsay (France)

    2014-12-21

    The use of high-intensity and/or heavy-ion beams in active targets and time-projection chambers is often limited by the strong ionization produced by the beam. Besides the difficulties associated with the saturation of the detector and electronics, beam-related signals may hide the physical events of interest or reduce the detector performance. In addition, space-charge effects may deteriorate the homogeneity of the electric drift field and distort the subsequent reconstruction of particle trajectories. In anticipation of future projects involving such conditions, a dedicated beam mask has been developed and tested in the MAYA active target. Experimental results with a {sup 136}Xe beam are presented.

  20. A mask for high-intensity heavy-ion beams in the MAYA active target

    Science.gov (United States)

    Rodríguez-Tajes, C.; Pancin, J.; Damoy, S.; Roger, T.; Babo, M.; Caamaño, M.; Farget, F.; Grinyer, G. F.; Jacquot, B.; Pérez-Loureiro, D.; Ramos, D.; Suzuki, D.

    2014-12-01

    The use of high-intensity and/or heavy-ion beams in active targets and time-projection chambers is often limited by the strong ionization produced by the beam. Besides the difficulties associated with the saturation of the detector and electronics, beam-related signals may hide the physical events of interest or reduce the detector performance. In addition, space-charge effects may deteriorate the homogeneity of the electric drift field and distort the subsequent reconstruction of particle trajectories. In anticipation of future projects involving such conditions, a dedicated beam mask has been developed and tested in the MAYA active target. Experimental results with a 136Xe beam are presented.

  1. Experimental results of beryllium exposed to intense high energy proton beam pulses

    Energy Technology Data Exchange (ETDEWEB)

    Ammigan, K. [Fermilab; Hartsell, B. [Fermilab; Hurh, P. [Fermilab; Zwaska, R. [Fermilab; Butcher, M. [CERN; Guinchard, M. [CERN; Calviani, M. [CERN; Losito, R. [CERN; Roberts, S. [Culham Lab; Kuksenko, V. [Oxford U.; Atherton, A. [Rutherford; Caretta, O. [Rutherford; Davenne, T. [Rutherford; Densham, C. [Rutherford; Fitton, M. [Rutherford; Loveridge, J. [Rutherford; O' Dell, J. [Rutherford

    2017-02-10

    Beryllium is extensively used in various accelerator beam lines and target facilities as a material for beam windows, and to a lesser extent, as secondary particle production targets. With increasing beam intensities of future accelerator facilities, it is critical to understand the response of beryllium under extreme conditions to reliably operate these components as well as avoid compromising particle production efficiency by limiting beam parameters. As a result, an exploratory experiment at CERN’s HiRadMat facility was carried out to take advantage of the test facility’s tunable high intensity proton beam to probe and investigate the damage mechanisms of several beryllium grades. The test matrix consisted of multiple arrays of thin discs of varying thicknesses as well as cylinders, each exposed to increasing beam intensities. This paper outlines the experimental measurements, as well as findings from Post-Irradiation-Examination (PIE) work where different imaging techniques were used to analyze and compare surface evolution and microstructural response of the test matrix specimens.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-04-28

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

  3. Intense highly charged ion beam production and operation with a superconducting electron cyclotron resonance ion source

    Science.gov (United States)

    Zhao, H. W.; Sun, L. T.; Guo, J. W.; Lu, W.; Xie, D. Z.; Hitz, D.; Zhang, X. Z.; Yang, Y.

    2017-09-01

    The superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is a superconducting-magnet-based electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged heavy ion beams. It is one of the best performing ECRISs worldwide and the first superconducting ECRIS built with an innovative magnet to generate a high strength minimum-B field for operation with heating microwaves up to 24-28 GHz. Since its commissioning in 2005, SECRAL has so far produced a good number of continuous wave intensity records of highly charged ion beams, in which recently the beam intensities of 40Ar+ and 129Xe26+ have, for the first time, exceeded 1 emA produced by an ion source. Routine operations commenced in 2007 with the Heavy Ion accelerator Research Facility in Lanzhou (HIRFL), China. Up to June 2017, SECRAL has been providing more than 28,000 hours of highly charged heavy ion beams to the accelerator demonstrating its great capability and reliability. The great achievement of SECRAL is accumulation of numerous technical advancements, such as an innovative magnetic system and an efficient double-frequency (24 +18 GHz ) heating with improved plasma stability. This article reviews the development of SECRAL and production of intense highly charged ion beams by SECRAL focusing on its unique magnet design, source commissioning, performance studies and enhancements, beam quality and long-term operation. SECRAL development and its performance studies representatively reflect the achievements and status of the present ECR ion source, as well as the ECRIS impacts on HIRFL.

  4. The design and construction of a pulsed beam generation system based on high intensity cyclotron

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In order to perform the studies on a pulsed beam generation system based on a high intensity cyclotron, a test beam line with a pulsed beam generation for a 10 MeV compact cyclotron (CYCIAE-10) has been designed and constructed at China Institute of Atomic Energy (CIAE). A 70 MHz continuous H- beam can be pulsed to the pulse length of less than 10 ns with a repetition rate of 4.4 MHz. The sine waveform with a frequency of 2.2 MHz is adopted for the chopper and a mesh structure with single drift and dual gaps is used for the 70 MHz buncher. A helical resonator is designed and constructed based on simulations and experiments on the RF matching for the chopper. A helical inductance loop that is exceptionally large of its kind and equipped with water cooling for the resonator has been successfully wound and a 500 W solid RF amplifier has been manufactured. A special measuring device has been designed, which can be used to measure both the DC beam and the pulsed beam. The required pulsed beam was obtained after pulsed beam tuning.

  5. Beam-Induced Effects and Radiological Issues in High-Intensity High-Energy Fixed Target Experiments

    CERN Document Server

    Mokhov, N V; Drozhdin, A I; Pronskikh, V S; Reitzner, D; Tropin, I S; Vaziri, K

    2014-01-01

    The next generation of accelerators for Megawatt proton and heavy-ion beams moves us into a completely new domain of extreme specific energies of up to 0.1 MJ/g (Megajoule/gram) and specific power up to 1 TW/g (Terawatt/gram) in beam interactions with matter. This paper is focused on deleterious effects of controlled and uncontrolled impacts of high-intensity beams on components of beam-lines, target stations, beam absorbers, shielding and environment. Two new experiments at Fermilab are taken as an example. The Long-Baseline Neutrino Experiment (LBNE) will explore the interactions and transformations of the world's highest-intensity neutrino beam by sending it from Fermilab more than 1,000 kilometers through the Earth's mantle to a large liquid argon detector. The Mu2e experiment is devoted to studies of the conversion of a negative muon to electron in the field of a nucleus without emission of neutrinos.

  6. Parasitic slow extraction of extremely weak beam from a high-intensity proton rapid cycling synchrotron

    Science.gov (United States)

    Zou, Ye; Tang, Jingyu; Yang, Zheng; Jing, Hantao

    2014-02-01

    This paper proposes a novel method to extract extremely weak beam from a high-intensity proton rapid cycling synchrotron (RCS) in the parasitic mode, while maintaining the normal fast extraction. The usual slow extraction method from a synchrotron by employing third-order resonance cannot be applied in a high-intensity RCS due to a very short flat-top at the extraction energy and the strict control on beam loss. The proposed parasitic slow extraction method moves the beam to scrape a scattering foil prior to the fast beam extraction by employing either a local orbit bump or momentum deviation or their combination, so that the halo part of the beam will be scattered. A part of the scattered particles will be extracted from the RCS and guided to the experimental area. The slow extraction process can last about a few milliseconds before the beam is extracted by the fast extraction system. The method has been applied to the RCS of China Spallation Neutron Source. With 1.6 GeV in the extraction energy, 62.5 μA in the average current and 25 Hz in the repetition rate for the RCS, the proton intensity by the slow extraction method can be up to 2×104 protons per cycle or 5×105 protons per second. The extracted beam has also a good time structure of approximately uniform in a spill which is required for many applications such as detector tests. Detailed studies including the scattering effect in the foil, the local orbit bump by the bump magnets and dispersive orbit bump by modifying the RF pattern, the multi-particle simulations by ORBIT and TURTLE codes, and some technical features for the extraction magnets are presented.

  7. High intensity single bunch operation with heavy periodic transient beam loading in wide band rf cavities

    Science.gov (United States)

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

    2015-09-01

    The rapid cycling synchrotron (RCS) in the Japan Proton Accelerator Research Complex (J-PARC) was originally designed to accelerate two high intensity bunches, while some of neutron experiments in the materials and life science experimental facility and a muon experiment using main ring beams require a single bunch operation mode, in which one of the two rf buckets is filled and the other is empty. The beam intensity in the single bunch operation has been limited by longitudinal beam losses due to the rf bucket distortions by the wake voltage of the odd harmonics (h =1 ,3 ,5 ) in the wide band magnetic alloy cavities. We installed an additional rf feedforward system to compensate the wake voltages of the odd harmonics (h =1 ,3 ,5 ). The additional system has a similar structure as the existing feedforward system for the even harmonics (h =2 ,4 ,6 ). We describe the function of the feedforward system for the odd harmonics, the commissioning methodology, and the commissioning results. The longitudinal beam losses during the single bunch acceleration disappeared with feedforward for the odd harmonics. We also confirmed that the beam quality in the single bunch acceleration are similar to that of the normal operation with two bunches. Thus, high intensity single bunch acceleration at the intensity of 2.3 ×1013 protons per bunch has been achieved in the J-PARC RCS. This article is a follow-up of our previous article, Phys. Rev. ST Accel. Beams 14, 051004 (2011). The feedforward system extension for single bunch operation was successful.

  8. Tune measurements with high intensity ion beams at GSI SIS-18

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Rahul [GSI, Darmstadt (Germany); TEMF, TU Darmstadt (Germany); Forck, Peter; Kowina, Piotr; Kaufmann, Wolfgang [GSI, Darmstadt (Germany); Weiland, Thomas [TEMF, TU Darmstadt (Germany)

    2012-07-01

    A precise tune measurement during a full accelerating cycle is required to achieve stable high current operation. A new system has been commissioned at GSI for position, orbit and tune measurements. It consists of three distinct parts; an exciter which provides power to excite coherent betatron oscillations in the bunched beam; Fast ADCs to digitize the BPM signals at 125 MSa/s; the post processing electronics uses digitized BPM signals to acquire one position value per bunch. Subsequently the baseband tune is determined by Fourier transformation of the position data. Experiments were conducted to understand the effects of high beam intensity on tune at injection plateau (11.4 MeV/u) and during acceleration ramp (11.4-600 MeV/u). These experiments were performed with U{sup 73+} and Ar{sup 18+} ion beam at highest achievable intensities of 2.10{sup 9} and 2.5.10{sup 10} respectively. Tune shift with increased intensity was observed. The working principle of the tune measurement system and observed high intensity effects on tune will be reported in this contribution.

  9. Simulation of the Beam Dump for a High Intensity Electron Gun

    CERN Document Server

    Doebert, S; Lefevre, T; Pepitone, K

    2014-01-01

    The CLIC Drive Beam is a high-intensity pulsed electron beam. A test facility for the Drive Beam electron gun will soon be commissioned at CERN. In this contribution we outline the design of a beam dump / Faraday cup capable of resisting the beam’s thermal load. The test facility will operate initially up to 140 keV. At such low energies, the electrons are absorbed very close to the surface of the dump, leading to a large energy deposition density in this thin layer. In order not to damage the dump, the beam must be spread over a large surface. For this reason, a small-angled cone has been chosen. Simulations using Geant4 have been performed to estimate the distribution of energy deposition in the dump. The heat transport both within the electron pulse and between pulses has been modelled using finite element methods to check the resistance of the dump at high repetition rates. In addition, the possibility of using a moveable dump to measure the beam profile and emittance is discussed.

  10. Study of Radiation Damage in Lead Tungstate Crystals Using Intense High Energy Beams

    CERN Document Server

    Batarin, V; Butler, J; Cheung, H; Datsko, V S; Davidenko, A; Derevshchikov, A A; Dzhelyadin, R I; Fomin, Y; Frolov, V; Goncharenko, Yu M; Grishin, V; Kachanov, V A; Khodyrev, V Yu; Khroustalev, K; Konoplyannikov, A K; Konstantinov, A S; Kravtsov, V; Kubota, Y; Leontiev, V M; Lukanin, V S; Maisheev, V; Matulenko, Yu A; Melnik, Yu M; Meshchanin, A P; Mikhalin, N; Minaev, N G; Mochalov, V; Morozov, D A; Mountain, R; Nogach, L V; Pikalov, V A; Ryazantsev, A; Semenov, P A; Shestermanov, K E; Soloviev, L; Solovyanov, V L; Stone, S; Ukhanov, M N; Uzunian, A V; Vasilev, A; Yakutin, A; Yarba, J V

    2003-01-01

    We report on the effects of radiation on the light output of lead tungstate crystals. The crystals were irradiated by pure, intense high energy electron and hadron beams as well as by a mixture of hadrons, neutrons and gammas. The crystals were manufactured in Bogoroditsk, Apatity (both Russia), and Shanghai (China). These studies were carried out at the 70-GeV proton accelerator in Protvino.

  11. Study of radiation damage in lead tungstate crystals using intense high-energy beams

    Energy Technology Data Exchange (ETDEWEB)

    Batarin, V.A.; Brennan, T.; Butler, J.; Cheung, H.; Datsko, V.S.; Davidenko, A.M.; Derevschikov, A.A.; Dzhelyadin, R.I.; Fomin, Y.V.; Frolov, V.; Goncharenko, Y.M.; Grishin, V.N.; Kachanov, V.A.; Khodyrev, V.Y.; Khroustalev, K.; Konoplyannikov, A.K.; Konstantinov, A.S.; Kravtsov, V.I.; Kubota, Y.; Leontiev, V.M.; Lukanin, V.S.; Maisheev, V.A.; Matulenko, Y.A.; Melnick, Y.M.; Meschanin, A.P.; Mikhalin, N.E.; Minaev, N.G.; Mochalov, V.V.; Morozov, D.A.; Mountain, R.; Nogach, L.V.; Pikalov, V.A.; Ryazantsev, A.V.; Semenov, P.A. E-mail: semenov@mx.ihep.su; Shestermanov, K.E.; Soloviev, L.F.; Solovianov, V.L.; Stone, S.; Ukhanov, M.N.; Uzunian, A.V.; Vasiliev, A.N.; Yakutin, A.E.; Yarba, J

    2003-10-21

    We report on the effects of radiation on the light output of lead tungstate crystals. The crystals were irradiated by pure, intense high-energy electron and hadron beams as well as by a mixture of hadrons, neutrons and gammas. The crystals were manufactured in Bogoroditsk, Apatity (both Russia), and Shanghai (China). These studies were carried out at the 70-GeV proton accelerator in Protvino.

  12. Control And Transport Of Intense Electron Beams

    CERN Document Server

    Li, H

    2004-01-01

    The transport of intense beams for advanced accelerator applications with high-intensity beams such as heavy-ion inertial fusion, spallation neutron sources, and intense light sources requires tight control of beam characteristics over long distances. The University of Maryland Electron Ring (UMER), which uses low energy, high current electron beams to model the transport physics of intense space-charge-dominated beams, employs real-time beam characterization and control in order to optimize beam quality throughout the strong focusing lattice. We describe in this dissertation the main beam control techniques used in UMER, which include optimal beam steering by quadrupole scans, beam rotation correction using a skew corrector, rms envelope matching and optimization, empirical envelope matching, beam injection, and phase space reconstruction using a tomographic method. Using these control techniques, we achieved the design goals for UMER. The procedure is not only indispensable for optimum beam transport over l...

  13. Special diagnostic methods and beam loss control on high intensity proton synchrotrons and storage rings Circular proton accelerator

    CERN Document Server

    Warsop, C M

    2002-01-01

    Two topics concerning high intensity, medium energy, circular proton accelerators have been studied: specialist diagnostics and beam loss control. The use of specially configured, low intensity diagnostic beams to help measure, understand and control high intensity beams is described. The ideas are developed and demonstrated on the ISIS 800 MeV, high intensity proton synchrotron at the Rutherford Appleton Laboratory in the UK. It is shown that these techniques make much new and valuable information available, which is particularly useful in achieving the precise beam optimisation required for low and controlled losses. Beam loss control in the proposed European Spallation Source (ESS) accumulator rings is studied. The expected losses are summarised, and a design for the beam collimation system presented. A new code for the simulation of loss control is outlined, and then used to test the collimation system under most foreseeable conditions. It is expected that the required loss control levels will be achievab...

  14. Halo Coupling and Cleaning by a Space Charge Resonance in High Intensity Beams

    CERN Document Server

    Hofmann, Ingo

    2013-01-01

    We show that the difference resonance driven by the space charge pseudo-octupole of high-intensity beams not only couples the beam core emittances; it can also lead to emittance exchange in the beam halo, which is of relevance for beam loss in high intensity accelerators. With reference to linear accelerators the "main resonance" kz/kxy =1 (corresponding to the Montague resonance 2Qx-2Qy=0 in circular accelerators) may lead to such a coupling and transfer of halo between planes. Coupling of transverse halo into the longitudinal plane - or vice versa - can occur even if the core (rms) emittances are exactly or nearly equal. This halo argument justifies additional caution in linac design including consideration of avoiding an equipartitioned design. At the same time, however, this mechanism may also qualify as active dynamical halo cleaning scheme by coupling a halo from the longitudinal plane into the transverse plane, where local scraping is accessible. We present semi-analytical emittance coupling rates and ...

  15. Roman Pot Insertions in High-Intensity Beams for the CT-PPS Project at LHC

    CERN Document Server

    Deile, Mario; Mereghetti, Alessio; Mirarchi, Daniele; Redaelli, Stefano; Salvachua, Belen; Salvant, Benoit; Valentino, Gianluca

    2016-01-01

    The CMS-TOTEM Precision Proton Spectrometer (CT-PPS) at the LHC IP5 aims at exploring diffractive physics at high luminosity in standard LHC fills. It is based on 14 Roman Pots (RPs), designed to host tracking and time-of-flight detectors for measuring the kinematics of leading protons. To reach the physics goals, the RPs will finally have to approach the beams to distances of 15 beam σs (i.e. ~1.5 mm) or closer. After problems with showers and impedance heating in first high-luminosity RP insertions in 2012, the LS1 of LHC was used for upgrades in view of impedance minimisation and for adding new collimators to intercept RP-induced showers. In 2015 the effectiveness of these improvements was shown by successfully inserting the RPs in all LHC beam intensity steps to a first-phase distance of ~25 σs. This contribution reviews the measurements of debris showers and impedance effects, i.e. the data from Beam Loss Monitors, beam vacuum gauges and temperature sensors. The dependences of the observables on the lu...

  16. Generation of heavy ion beams using high-intensity short pulse lasers

    Science.gov (United States)

    Petrov, George; McGuffey, Chris; Thomas, Alec; Krushelnick, Karl; Beg, Farhat

    2016-10-01

    A theoretical study of ion acceleration from high-Z material irradiated by intense sub-picosecond lasers is presented. The underlying physics of beam formation and acceleration is similar for light and heavy ions, however, nuances of the acceleration process make the heavy ions more challenging. At least four technical hurdles have been identified: low charge-to-mass ratio, limited number of ions amenable to acceleration, delayed acceleration and poor energy coupling due to high reflectivity of the plasma. Using two dimensional particle-in-cell (PIC) simulations, we observed transitions from Radiation Pressure Acceleration (RPA) to the Breakout Afterburner regime (BoA) and to Target Normal Sheath Acceleration (TNSA) akin to light ions. The numerical simulations predict gold ions beams with high directionality (high fluxes (>1011 ions/sr) and energy (>10 MeV/nucleon) from laser systems delivering >20 J of energy on target.

  17. High-intensity laser-accelerated ion beam produced from cryogenic micro-jet target

    Energy Technology Data Exchange (ETDEWEB)

    Gauthier, M., E-mail: maxence.gauthier@stanford.edu; Kim, J. B.; Curry, C. B.; Gamboa, E. J.; Göde, S.; Propp, A.; Glenzer, S. H. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Aurand, B.; Willi, O. [Heinrich-Heine-University Düsseldorf, Düsseldorf (Germany); Goyon, C.; Hazi, A.; Pak, A.; Ruby, J.; Williams, G. J. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Kerr, S. [University of Alberta, Edmonton, Alberta T6G 1R1 (Canada); Ramakrishna, B. [Indian Institute of Technology, Hyderabad (India); Rödel, C. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Friedrich-Schiller-University Jena, Jena (Germany)

    2016-11-15

    We report on the successful operation of a newly developed cryogenic jet target at high intensity laser-irradiation. Using the frequency-doubled Titan short pulse laser system at Jupiter Laser Facility, Lawrence Livermore National Laboratory, we demonstrate the generation of a pure proton beam a with maximum energy of 2 MeV. Furthermore, we record a quasi-monoenergetic peak at 1.1 MeV in the proton spectrum emitted in the laser forward direction suggesting an alternative acceleration mechanism. Using a solid-density mixed hydrogen-deuterium target, we are also able to produce pure proton-deuteron ion beams. With its high purity, limited size, near-critical density, and high-repetition rate capability, this target is promising for future applications.

  18. High-intensity laser-accelerated ion beam produced from cryogenic micro-jet target

    Science.gov (United States)

    Gauthier, M.; Kim, J. B.; Curry, C. B.; Aurand, B.; Gamboa, E. J.; Göde, S.; Goyon, C.; Hazi, A.; Kerr, S.; Pak, A.; Propp, A.; Ramakrishna, B.; Ruby, J.; Willi, O.; Williams, G. J.; Rödel, C.; Glenzer, S. H.

    2016-11-01

    We report on the successful operation of a newly developed cryogenic jet target at high intensity laser-irradiation. Using the frequency-doubled Titan short pulse laser system at Jupiter Laser Facility, Lawrence Livermore National Laboratory, we demonstrate the generation of a pure proton beam a with maximum energy of 2 MeV. Furthermore, we record a quasi-monoenergetic peak at 1.1 MeV in the proton spectrum emitted in the laser forward direction suggesting an alternative acceleration mechanism. Using a solid-density mixed hydrogen-deuterium target, we are also able to produce pure proton-deuteron ion beams. With its high purity, limited size, near-critical density, and high-repetition rate capability, this target is promising for future applications.

  19. Systematic investigations on high intense cluster-jet beams for storage ring experiments

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, Esperanza; Hergemoeller, Ann-Katrin; Taeschner, Alexander; Ortjohann, Hans-Werner; Bonaventura, Daniel; Khoukaz, Alfons [Institut fuer Kernphysik, Westfaelische Wilhelms-Universitaet Muenster (Germany)

    2012-07-01

    A high-density cluster-jet target will be one of two planned internal target stations for the PANDA experiment at the antiproton accelerator and storage ring HESR/FAIR. For the investigation of elementary anti pN interactions hydrogen and deuterium are of highest interest as used target material. Cluster-jet targets allow high and constant target densities at the interaction point, i.e. 2 m behind the nozzle, with the possibility of a continuous variation during operation. At the University of Muenster a cluster-jet target prototype was designed, built up and set succesfully into operation. The system is installed in complete PANDA geometry, so that the observed cluster beam characteristics can be directly transferred to the later situation at PANDA. Recent optical investigations on the cluster beam directly behind the nozzle resulted in the observation of distinct density structures when the target is operated at highest densities. The development and installation of a special nozzle tilting system allows for the extraction of these high-intense core beams, leading to a significant improvement of the target density. The performance and achieved densities of cluster beams are presented.

  20. High resolution study of the inclusive production of massive muon pairs by intense pion beams

    CERN Multimedia

    2002-01-01

    This experiment measures with high resolution and large acceptance the inclusive production of massive muon pairs with the intense pion beam (up to $10^{10} \\pi/$pulse) in the experimental hall ECN3. The experiment explores extended M$^{2}$/s, x and transverse momentum ranges. The study of the departures of the lepton-pair production cross- section from scaling constitutes a good test of QCD ideas; in the framework of the 'Drell-Yan' process, the experiment allows a detailed study of the pion parton distribution functions. The detector consists of a beam dump, a pulsed toroidal a magnet, MWPC's and scintillator hodoscopes. Its $\\sim 2$% mass resolution at 10 GeV is adequate for the substraction of resonances in the high-mass region.

  1. Bessel-Gauss beam enhancement cavities for high-intensity applications.

    Science.gov (United States)

    Putnam, William P; Schimpf, Damian N; Abram, Gilberto; Kärtner, Franz X

    2012-10-22

    We introduce Bessel-Gauss beam enhancement cavities that may circumvent the major obstacles to more efficient cavity-enhanced high-field physics such as high-harmonic generation. The basic properties of Bessel-Gauss beams are reviewed and their transformation properties through simple optical systems (consisting of spherical and conical elements) are presented. A general Bessel-Gauss cavity design strategy is outlined, and a particular geometry, the confocal Bessel-Gauss cavity, is analyzed in detail. We numerically simulate the confocal Bessel-Gauss cavity and present an example cavity with 300 MHz repetition rate supporting an effective waist of 33 μm at the focus and an intensity ratio from the focus to the cavity mirror surfaces of 1.5 × 10(4).

  2. Nuclear Structure at the Legnaro National Laboratories:. from High Intensity Stable to Radioactive Nuclear Beams

    Science.gov (United States)

    de Angelis, G.

    2007-04-01

    To understand the properties of a nucleus, apart from establishing the interaction between its components, it is necessary to determine the arrangement of the nucleons, i.e. the structure of a nucleus. So far our knowledge about the structure of nuclei is mostly limited to nuclei close to the valley of stability, or nuclei with a deficiency of neutrons, which can be produced in fusion-evaporation reactions with stable beams and stable targets. Future perspectives in nuclear structure rely on radioactive ion beams (RIB) as well as on high intensity beams of stable ions (HISB). A world wide effort is presently going on in order to built the next generation radioactive ion beam facilities like the FAIR and the EURISOL projects. The LNL are contributing to such development through the design study of the EURISOL project as well as through the design and construction of the intermediate facility SPES. Concerning the instrumentation, particularly powerful is the combination of large acceptance spectrometers with highly segmented γ-detector arrays. An example is the CLARA γ-ray detector array coupled with the PRISMA spectrometer at the Legnaro National Laboratories (LNL). The physics aims achievable with such device complement studies performed with current radioactive beam (RIB) facilities. With this set-up we have recently investigated the stability of the N=50 shell closure. Here the comparison of the experimental data with shell model calculations seems to indicate a persistence of the N=50 shell gap down to Z=31. Also the study of proton rich nuclei can strongly benefit from the use of high intensity stable beams using fusion evaporation reactions at energies close to the Coulomb barrier. Future perspectives at LNL are based on an increase in intensity as well as on the availability of heavy ion species. Moreover a new ISOL facility (SPES) dedicated to the production and acceleration of radioactive neutron rich species is now under development at LNL. Among the new

  3. High Intensity Laser Power Beaming Architecture for Space and Terrestrial Missions

    Science.gov (United States)

    Nayfeh, Taysir; Fast, Brian; Raible, Daniel; Dinca, Dragos; Tollis, Nick; Jalics, Andrew

    2011-01-01

    High Intensity Laser Power Beaming (HILPB) has been developed as a technique to achieve Wireless Power Transmission (WPT) for both space and terrestrial applications. In this paper, the system architecture and hardware results for a terrestrial application of HILPB are presented. These results demonstrate continuous conversion of high intensity optical energy at near-IR wavelengths directly to electrical energy at output power levels as high as 6.24 W from the single cell 0.8 cm2 aperture receiver. These results are scalable, and may be realized by implementing receiver arraying and utilizing higher power source lasers. This type of system would enable long range optical refueling of electric platforms, such as MUAV s, airships, robotic exploration missions and provide power to spacecraft platforms which may utilize it to drive electric means of propulsion.

  4. Design and development of a tantalum foil target for the production of high intensity radioactive beams

    CERN Document Server

    Densham, Cristopher John

    2000-01-01

    The design and development of a high power target and ion source for the production of Radioactive Beams at intensities approaching two orders of magnitude greater than currently possible is presented. This was a key aim of the RIST experiment, designed to utilise the proton synchrotron of the ISIS facility at Rutherford Appleton laboratory, Chilton, Oxfordshire, where an 800 MeV proton beam is available at currents of up to 200 mu A. A number of different target designs were considered and analysed, and high temperature power dissipation tests were conducted. This culminated in the manufacture of a diffusion bonded structure comprising 6000 separate tantalum foil discs and spacer washers. The target was installed in the RIST facility, and thermal tests using electron beam heating demonstrated that the target was capable of dissipating 24 kW by thermal radiation, at the desired temperature of 2000 deg C. This is equivalent to running with the 800 MeV ISIS proton beam at a current of 100 mu A. A smaller diamet...

  5. Design study of a radio-frequency quadrupole for high-intensity beams

    Science.gov (United States)

    Bahng, Jungbae; Kim, Eun-San; Choi, Bong-Hyuk

    2017-07-01

    The Rare isotope Accelerator Of Newness (RAON) heavy-ion accelerator has been designed for the Rare Isotope Science Project (RISP) in Korea. The RAON will produce heavy-ion beams from 660-MeV-proton to 200-MeV/u-uranium with continuous wave (CW) power of 400 kW to support research in various scientific fields. Its system consists of an ECR ion source, LEBTs with 10 keV/u, CW RFQ accelerator with 81.25 MHz and 500 keV/u, a MEBT system, and a SC linac. In detail, the driver linac system consists of a Quarter Wave Resonator (QWR) section with 81.25 MHz and a Half Wave Resonator (HWR) section with 162.5 MHz, Linac-1, and a Spoke Cavity section with 325 MHz, Linac-2. These linacs have been designed to optimize the beam parameters to meet the required design goals. At the same time, a light-heavy ion accelerator with high-intensity beam, such as proton, deuteron, and helium beams, is required for experiments. In this paper, we present the design study of the high intensity RFQ for a deuteron beam with energies from 30 keV/u to 1.5 MeV/u and currents in the mA range. This system is composed of an Penning Ionization Gauge ion source, short LEBT with a RF deflector, and shared SC Linac. In order to increase acceleration efficiency in a short length with low cost, the 2nd harmonic of 162.5 MHz is applied as the operation frequency in the D+ RFQ design. The D+ RFQ is designed with 4.97 m, 1.52 bravery factor. Since it operates with 2nd harmonic frequency, the beam should be 50% of the duty factor while the cavity should be operated in CW mode, to protect the downstream linac system. We focus on avoiding emittance growth by the space-charge effect and optimizing the RFQ to achieve a high transmission and low emittance growth. Both the RFQ beam dynamics study and RFQ cavity design study for two and three dimensions will be discussed. Supported by Korea University Future Research Grant

  6. Development of a laser ion source for production of high-intensity heavy-ion beams

    Science.gov (United States)

    Kashiwagi, H.; Yamada, K.; Kurashima, S.

    2017-09-01

    A laser ion source has been developed as a high-intensity source for the ion implanter and the single pulsed beam of the azimuthally varying field cyclotron at TIARA. Highly charged beams of C5+ and C6+ ions and low-charged beams of heavy ions such as C, Al, Ti, Cu, Au, and Pt are required for the single-pulse acceleration in the cyclotron and for the ion implanter, respectively. In the vacuum chamber of the ion source, a target holder on a three-dimensional linear-motion stage provides a fresh surface for each laser shot. A large-sized target with a maximum size of 300 mm × 135 mm is mounted on the holder for long-term operation. The ion current (ion charge flux) in the laser-produced plasma is measured by a Faraday cup and time-of-flight spectra of each charge state are measured using a 90° cylindrical electrostatic analyzer just behind the Faraday cup. Carbon-plasma-generation experiments indicate that the source produces intense high- and low-charged pulsed ion beams. At a laser energy of 483 mJ (2.3 × 1013 W/cm2), average C6+ current of 13 mA and average C5+ current of 23 mA were obtained over the required time duration for single-pulse acceleration in the cyclotron (49 ns for C6+ and 80 ns for C5+). Furthermore, at 45 mJ (2.1 × 1012 W/cm2), an average C2+ current of 1.6 mA over 0.88 μs is obtained.

  7. Parallel plate chambers for monitoring the profiles of high-intensity pulsed antiproton beams

    CERN Document Server

    Hori, Masaki

    2004-01-01

    Two types of beam profile monitor with thin parallel-plate electrodes have been used in experiments carried out at the Low Energy Antiproton Ring (LEAR) and Antiproton Decelerator (AD) of CERN. The detectors were used to measure non-destructively the spatial profiles, absolute intensities, and time structures of 100-300-ns- long beam pulses containing between 10**7 and 10**9 antiprotons. The first of these monitors was a parallel plate ionization chamber operated at gas pressure P=65 mbar. The other was a secondary electron emission detector, and was operated in the ultra-high vacuum of the AD. Both designs may be useful in medical and commercial applications. The position-sensitive electrodes in these detectors were manufactured by a novel method in which a laser trimmer was used to cut strip patterns on metallized polyester foils.

  8. On the Possibility of Using Nonlinear Elements for Landau Damping in High-Intensity Beams

    Energy Technology Data Exchange (ETDEWEB)

    Alexahin, Y. [Fermilab; Gianfelice-Wendt, E. [Fermilab; Lebedev, V. [Fermilab; Valishev, A. [Fermilab

    2016-09-30

    Direct space-charge force shifts incoherent tunes downwards from the coherent ones breaking the Landau mechanism of coherent oscillations damping at high beam intensity. To restore it nonlinear elements can be employed which move back tunes of large amplitude particles. In the present report we consider the possibility of creating a “nonlinear integrable optics” insertion in the Fermilab Recycler to host either octupoles or hollow electron lens for this purpose. For comparison we also consider the classic scheme with distributed octupole families. It is shown that for the Proton Improvement Plan II (PIP II) parameters the required nonlinear tune shift can be created without destroying the dynamic aperture.

  9. Propagation instabilities of high-intensity laser-produced electron beams.

    Science.gov (United States)

    Tatarakis, M; Beg, F N; Clark, E L; Dangor, A E; Edwards, R D; Evans, R G; Goldsack, T J; Ledingham, K W D; Norreys, P A; Sinclair, M A; Wei, M-S; Zepf, M; Krushelnick, K

    2003-05-01

    Measurements of energetic electron beams generated from ultrahigh intensity laser interactions (I>10(19) W/cm(2)) with dense plasmas are discussed. These interactions have been shown to produce very directional beams, although with a broad energy spectrum. In the regime where the beam density approaches the density of the background plasma, we show that these beams are unstable to filamentation and "hosing" instabilities. Particle-in-cell simulations also indicate the development of such instabilities. This is a regime of particular interest for inertial confinement fusion applications of these beams (i.e., "fast ignition").

  10. Investigation of Generation, Acceleration, Transport and Final Focusing of High-Intensity Heavy Ion Beams from Sources to Targets

    Energy Technology Data Exchange (ETDEWEB)

    Chiping Chen

    2006-10-26

    Under the auspices of the research grant, the Intense Beam Theoretical Research Goup at Massachusetts Institute of Technology's Plasma Science and Fusion Center made significant contributions in a number of important areas in the HIF and HEDP research, including: (a) Derivation of rms envelope equations and study of rms envelope dynamics for high-intensity heavy ion beams in a small-aperture AG focusing transport systems; (b) Identification of a new mechanism for chaotic particle motion, halo formation, and beam loss in high-intensity heavy ion beams in a small-aperture AG focusing systems; Development of elliptic beam theory; (d) Study of Physics Issues in the Neutralization Transport Experiment (NTX).

  11. 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.

  12. Experience with High-Intensity Beam Scraping and Tail Population at the Large Hadron Collider

    CERN Document Server

    Redaelli, S; Burkart, F; Bruce, R; Mirarchi, D; Salvachua, B; Valentino, G; Wollmann, D

    2013-01-01

    The population of beam tails at the Large Hadron Collider (LHC) is a source of concern for the operation at higher beam energies and intensities when even small fractions of the beam could represent a potential danger is case of slow or fast losses, e.g. caused by orbit transients or by collimator movements. Different studies have been performed using the technique of collimator scans to probe the beam tail population in different conditions. The experience accumulated during the operation at 3.5 TeV and 4 TeV is reviewed.

  13. Analytic fluid theory of beam spiraling in high-intensity cyclotrons

    Directory of Open Access Journals (Sweden)

    A. J. Cerfon

    2013-02-01

    Full Text Available Using a two-dimensional fluid description, we investigate the nonlinear radial-longitudinal dynamics of intense beams in isochronous cyclotrons in the nonrelativistic limit. With a multiscale analysis separating the time scale associated with the betatron motion and the slower time scale associated with space-charge effects, we show that the longitudinal-radial vortex motion can be understood in the frame moving with the charged beam as the nonlinear advection of the beam by the E×B velocity field, where E is the electric field due to the space charge and B is the external magnetic field. This interpretation provides simple explanations for the stability of round beams and for the development of spiral halos in elongated beams. By numerically solving the nonlinear advection equation for the beam density, we find that it is also in quantitative agreement with results obtained in particle-in-cell simulations.

  14. Thermal analysis of injection beam dump of high-intensity rapid-cycling synchrotron in J-PARC

    Science.gov (United States)

    Kamiya, J.; Saha, P. K.; Yamamoto, K.; Kinsho, M.; Nihei, T.

    2017-10-01

    The beam dump at the beam injection area in the J-PARC 3-GeV rapid cycling synchrotron (RCS) accepts beams that pass through the charge exchange foil without ideal electron stripping during the multi-turn beam injection. The injection beam dump consists of the beam pipe, beam stopper, radiation shield, and cooling mechanism. The ideal beam power into the injection beam dump is 400 W in the case of design RCS extraction beam power of 1 MW with a healthy foil, which has 99.7 % charge stripping efficiency. On the other hand, as a radiation generator, the RCS is permitted to be operated with maximum average beam power of 4 kW into the injection beam dump based on the radiation shielding calculation, in consideration of lower charge stripping efficiency due to the foil deterioration. In this research, to evaluate the health of the RCS injection beam dump system from the perspective of the heat generation, a thermal analysis was performed based on the actual configuration with sufficiently large region, including the surrounding concrete and soil. The calculated temperature and heat flux density distribution showed the validity of the mesh spacing and model range. The calculation result showed that the dumped 4 kW beam causes the temperature to increase up to 330, 400, and 140 °C at the beam pipe, beam stopper, and radiation shield, respectively. Although these high temperatures induce stress in the constituent materials, the calculated stress values were lower than the ultimate tensile strength of each material. Transient temperature analysis of the beam stopper, which simulated the sudden break of the charge stripper foil, demonstrated that one bunched beam pulse with the maximum beam power does not lead to a serious rise in the temperature of the beam stopper. Furthermore, from the measured outgassing rate of stainless steel at high temperature, the rise in beam line pressure due to additive outgassing from the heated beam pipe was estimated to have a negligible

  15. Future Perspectives in Nuclear Structure: From high intensity stable to radioactive nuclear beams

    Science.gov (United States)

    de Angelis, Giacomo

    2005-04-01

    Future perspectives in nuclear structure rely on radioactive nuclear beams as well as on high intensity beams of stable ions. Especially for neutron rich nuclei, deep-inelastic and multi-nucleon transfer reactions can be used to populate yrast and non yrast states. Particularly powerful is here the combination of large acceptance spectrometers with highly segmented γ-detector arrays. Such devices, eventually complemented by large cov- erage particle detectors, can provide the necessary channel selectivity to identify very rare signals. An example is the CLARA γ-ray detector array coupled with the PRISMA spectrometer at the Legnaro National Laboratories (LNL). The physics aims achievable with this setup will complement studies performed with current radioactive beam (RIB) facilities. With such set-up we have recently investigated the stability of the N=50 shell closure when moving towards more exotic systems. Here the comparison of the experi- mental data with shell model calculations seems to indicate a persistence of the N=50 shell gap down to Z=32. Future perspectives at LNL are based on an increase in in- tensity as well as on the availability of heavy ion species. Beams like 136Xe or 208Pb, which will be provided by the new PIAVE injector, can be used to drive the multinucleon flux toward the more exotic regions. Moreover a new ISOL facility (SPES) dedicated to the production and acceleration of radioactive neutron rich species is now under develop- ment at LNL. It will be based on an high intensity proton and deuteron LINAC. Induced fission fragments will be ionized and then accelerated using the presently existing super- conductive LINAC (ALPI). Among the new instrumentation the concept of γ-ray tracking has been recently introduced in nuclear spectroscopy. Detectors based on γ-ray tracking have position resolution capabilities with excellent performances both in efficiency and in achievable Doppler correction. A new γ-ray detector array (AGATA) based on

  16. Beam dynamic design of a high intensity injector for proton linac

    Science.gov (United States)

    Dou, Wei-Ping; Wang, Zhi-Jun; Jia, Fang-Jian; He, Yuan; Wang, Zhi; Lu, Yuan-Rong

    2016-08-01

    A compact room-temperature injector is designed to accelerate 100 mA proton beam from 45 keV to 4.06 MeV for the proposed high intensity proton linac at State Key Lab of Nuclear Physics and Technology in Peking university. The main feature is that the Radio Frequency Quadruple (RFQ) and the Drift Tube linac (DTL) sections are merged in one piece at the total length of 276 cm. The beam is matched in transverse directions with an compact internal doublet instead of an external matching section in between. The design has reached a high average accelerating gradient up to 1.55 MV/m with transmission efficiency of 95.9% at the consideration of high duty factor operation. The operation frequency is chose to be 200 MHz due to the already available RF power source. The injector combines a 150 cm long 4-vanes RFQ internal section from 45 keV to 618 keV with a 126 cm long H-type DTL section to 4.06 MeV. In general the design satisfy the challenges of the project requirements. And the details are presented in this paper.

  17. Beam dynamic design of a high intensity injector for proton linac

    Energy Technology Data Exchange (ETDEWEB)

    Dou, Wei-Ping, E-mail: douweiping@impcas.ac.cn [Institute of Modern Physics, The Chinese Academy of Sciences, Lanzhou 73000 (China); Wang, Zhi-Jun [Institute of Modern Physics, The Chinese Academy of Sciences, Lanzhou 73000 (China); Jia, Fang-Jian [State Key Lab of Nuclear Physics and Technology, Peking University, Beijing 100847 (China); He, Yuan, E-mail: hey@impcas.ac.cn [Institute of Modern Physics, The Chinese Academy of Sciences, Lanzhou 73000 (China); Wang, Zhi; Lu, Yuan-Rong [State Key Lab of Nuclear Physics and Technology, Peking University, Beijing 100847 (China)

    2016-08-11

    A compact room-temperature injector is designed to accelerate 100 mA proton beam from 45 keV to 4.06 MeV for the proposed high intensity proton linac at State Key Lab of Nuclear Physics and Technology in Peking university. The main feature is that the Radio Frequency Quadruple (RFQ) and the Drift Tube linac (DTL) sections are merged in one piece at the total length of 276 cm. The beam is matched in transverse directions with an compact internal doublet instead of an external matching section in between. The design has reached a high average accelerating gradient up to 1.55 MV/m with transmission efficiency of 95.9% at the consideration of high duty factor operation. The operation frequency is chose to be 200 MHz due to the already available RF power source. The injector combines a 150 cm long 4-vanes RFQ internal section from 45 keV to 618 keV with a 126 cm long H-type DTL section to 4.06 MeV. In general the design satisfy the challenges of the project requirements. And the details are presented in this paper.

  18. High intensity high charge state ion beam production with an evaporative cooling magnet ECRIS

    Energy Technology Data Exchange (ETDEWEB)

    Lu, W., E-mail: luwang@impcas.ac.cn; Qian, C.; Sun, L. T.; Zhang, X. Z.; Feng, Y. C.; Ma, B. H.; Zhao, H. W.; Zhan, W. L. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000 (China); Fang, X.; Guo, J. W.; Yang, Y. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xiong, B.; Ruan, L. [Institute of Electrical Engineering, CAS, Beijing 100190 (China); Xie, D. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2016-02-15

    LECR4 (Lanzhou ECR ion source No. 4) is a room temperature electron cyclotron resonance ion source, designed to produce high current, high charge state ion beams for the SSC-LINAC injector (a new injector for sector separated cyclotron) at the Institute of Modern Physics. LECR4 also serves as a PoP machine for the application of evaporative cooling technology in accelerator field. To achieve those goals, LECR4 ECR ion source has been optimized for the operation at 18 GHz. During 2014, LECR4 ion source was commissioned at 18 GHz microwave of 1.6 kW. To further study the influence of injection stage to the production of medium and high charge state ion beams, in March 2015, the injection stage with pumping system was installed, and some optimum results were produced, such as 560 eμA of O{sup 7+}, 620 eμA of Ar{sup 11+}, 430 eμA of Ar{sup 12+}, 430 eμA of Xe{sup 20+}, and so on. The comparison will be discussed in the paper.

  19. Comparison of Square and Radial Geometries for High Intensity Laser Power Beaming Receivers

    Science.gov (United States)

    Raible, Daniel E.; Fast, Brian R.; Dinca, Dragos; Nayfeh, Taysir H.; Jalics, Andrew K.

    2012-01-01

    In an effort to further advance a realizable form of wireless power transmission (WPT), high intensity laser power beaming (HILPB) has been developed for both space and terrestrial applications. Unique optical-to-electrical receivers are employed with near infrared (IR-A) continuous-wave (CW) semiconductor lasers to experimentally investigate the HILPB system. In this paper, parasitic feedback, uneven illumination and the implications of receiver array geometries are considered and experimental hardware results for HILPB are presented. The TEM00 Gaussian energy profile of the laser beam presents a challenge to the effectiveness of the receiver to perform efficient photoelectric conversion, due to the resulting non-uniform illumination of the photovoltaic cell arrays. In this investigation, the geometry of the receiver is considered as a technique to tailor the receiver design to accommodate the Gaussian beam profile, and in doing so it is demonstrated that such a methodology is successful in generating bulk receiver output power levels reaching 25 W from 7.2 sq cm of photovoltaic cells. These results are scalable, and may be realized by implementing receiver arraying and utilizing higher power source lasers to achieve a 1.0 sq m receiver capable of generating over 30 kW of electrical power. This type of system would enable long range optical "refueling" of electric platforms, such as MUAV s, airships, robotic exploration missions and provide power to spacecraft platforms which may utilize it to drive electric means of propulsion. In addition, a smaller HILPB receiver aperture size could be utilized to establish a robust optical communications link within environments containing high levels of background radiance, to achieve high signal to noise ratios.

  20. Extraction of high-intensity ion beams from a laser plasma by a pulsed spherical diode

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Oguri

    2005-06-01

    Full Text Available High-current Cu^{+} ion beams were extracted from a laser-produced plasma using a pulsed high-voltage multiaperture diode driven by an induction cavity. The amplitude and the duration of the extraction voltage were 130 kV and 450 ns, respectively. During the extraction, explosive beam divergence due to the strong space-charge force was suppressed by the focusing action of the gap between concentric hemispheres. Modulation of the extracted beam flux due to the plasma prefill in the gap has been eliminated by using a biased control grid put on the anode holes. By means of this extraction scheme we obtained a rectangular beam pulse with a rise time as short as ≈100  ns. The beam current behind the cathode was limited to ≈0.1   A, owing to space-charge effects, as well as to poor geometrical transmission through the cathode sphere. From the measurement of the extracted beam current density distribution along the beam axis and the beam profile measurement, we found a beam waist slightly downstream of the spherical center of the diode structure. The measured beam behavior was consistent with numerical results obtained via a 3D particle code. No serious degradation of the beam emittance was observed for the grid-controlled extraction scheme.

  1. A preliminary study of the feasibility of using superconducting quarter-wave resonators for accelerating high intensity proton beams

    Institute of Scientific and Technical Information of China (English)

    YANG Liu; LU Xiang-Yang; QUAN Sheng-Wen; YAO Zhong-Yuan; LUO Xing; ZHOU Kui

    2012-01-01

    The superconducting (SC) cavities currently used for the acceleration of protons at a low velocity range are based on half-wave resonators.Due to the rising demand on high current,the issue of beam loading and space-charge problems has arisen.Qualities of low cost and high accelerating efficiency are required for SC cavities,which are properly fitted by using SC quarter-wave resonators (QWR).We propose a concept of using QWRs with frequency 162.5 MHz to accelerate high current proton beams.The main factor limiting SC QWRs being applied to high current proton beams is vertical beam steering,which is dominantly caused by the magnetic field on axis.In this paper,we intend to analyze steering and eliminate it to verify the qualification of using QWRs to accelerate high intensity proton beams.

  2. Optical Frequency Optimization of a High Intensity Laser Power Beaming System Utilizing VMJ Photovoltaic Cells

    Science.gov (United States)

    Raible, Daniel E.; Dinca, Dragos; Nayfeh, Taysir H.

    2012-01-01

    An effective form of wireless power transmission (WPT) has been developed to enable extended mission durations, increased coverage and added capabilities for both space and terrestrial applications that may benefit from optically delivered electrical energy. The high intensity laser power beaming (HILPB) system enables long range optical 'refueling" of electric platforms such as micro unmanned aerial vehicles (MUAV), airships, robotic exploration missions and spacecraft platforms. To further advance the HILPB technology, the focus of this investigation is to determine the optimal laser wavelength to be used with the HILPB receiver, which utilizes vertical multi-junction (VMJ) photovoltaic cells. Frequency optimization of the laser system is necessary in order to maximize the conversion efficiency at continuous high intensities, and thus increase the delivered power density of the HILPB system. Initial spectral characterizations of the device performed at the NASA Glenn Research Center (GRC) indicate the approximate range of peak optical-to-electrical conversion efficiencies, but these data sets represent transient conditions under lower levels of illumination. Extending these results to high levels of steady state illumination, with attention given to the compatibility of available commercial off-the-shelf semiconductor laser sources and atmospheric transmission constraints is the primary focus of this paper. Experimental hardware results utilizing high power continuous wave (CW) semiconductor lasers at four different operational frequencies near the indicated band gap of the photovoltaic VMJ cells are presented and discussed. In addition, the highest receiver power density achieved to date is demonstrated using a single photovoltaic VMJ cell, which provided an exceptionally high electrical output of 13.6 W/sq cm at an optical-to-electrical conversion efficiency of 24 percent. These results are very promising and scalable, as a potential 1.0 sq m HILPB receiver of

  3. Electromagnetic Coupling Between High Intensity LHC Beams and the Synchrotron Radiation Monitor Light Extraction System

    CERN Document Server

    Andreazza, W; Bravin, E; Caspers, F; Garlasch`e, M; Gras, J; Goldblatt, A; Lefevre, T; Jones, R; Metral, E; Nosych, A; Roncarolo_, F; Salvant, B; Trad, G; Veness, R; Vollinger, C; Wendt, M

    2013-01-01

    The CERN LHC is equipped with two Synchrotron Radiation Monitor (BSRT) systems used to characterise transverse and longitudinal beam distributions. Since the end of the 2011 LHC run the light extraction system, based on a retractable mirror, has suffered deformation and mechanical failure that is correlated to the increase in beam intensity. Temperature probes have associated these observations to a strong heating of the mirror support with a dependence on the longitudinal bunch length and shape, indicating the origin as electromagnetic coupling between the beam and the structure. This paper combines all this information with the aim of characterising and improving the system in view of its upgrade during the current LHC shutdown. Beam-based observations are presented along with electromagnetic and thermomechanical simulations and complemented by laboratory measurements, including the study of the RF properties of different mirror bulk and coating materials.

  4. Understanding transverse tune spectrum for high intensity ions beams at GSI SIS-18

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Rahul; Boine-Frankenheim, Oliver [GSI, Darmstadt (Germany); TEMF, TU Darmstadt (Germany); Forck, Peter; Kowina, Piotr; Kaufmann, Wolfgang; Lang, Kevin; Haseitl, Rainer [GSI, Darmstadt (Germany); Weiland, Thomas [TEMF, TU Darmstadt (Germany)

    2013-07-01

    Several experiments involving transverse tune spectra measurements were performed at GSI SIS-18 with various beam intensities to understand the effect of intensity on tune spectra. Besides the machine tune, the spectra provides information about the intensity dependent coherent and the incoherent space charge tune shift. The space charge tune shift is measured from a fit of the observed shifted positions of the measured head tail modes to the predictions of an analytic model. Additionally, each mode is temporally identified by using a novel excitation mechanism and fast sampling ADCs. The longitudinal structure of each head tail mode gives a direct measurement of chromaticity.

  5. High-repetition rate relativistic electron beam generation from intense laser solid interactions

    Science.gov (United States)

    Batson, Thomas; Nees, John; Hou, Bixue; Thomas, A. G. R.; Krushelnick, Karl

    2015-05-01

    Relativistic electron beams have applications spanning materials science, medicine, and home- land security. Recent advances in short pulse laser technology have enabled the production of very high focused intensities at kHz rep rates. Consequently this has led to the generation of high ux sources of relativistic electrons- which is a necessary characteristic of these laser plasma sources for any potential application. In our experiments, through the generation of a plasma with the lambda cubed laser system at the University of Michigan (a 5 × 1018W=cm2, 500 Hz, Ti:Sapphire laser), we have measured electrons ejected from the surface of fused silica nd Cu targets having energies in excess of an MeV. The spectrum of these electrons was measured with respect to incident laser angle, prepulse timing, and focusing conditions. While taken at a high repetition rate, the pulse energy of the lambda cubed system was consistently on the order of 10 mJ. In order to predict scaling of the electron energy with laser pulse energy, simulations are underway which compare the spectrum generated with the lambda cubed system to the predicted spectrum generated on the petawatt scale HERCULES laser system at the University of Michigan.

  6. A New High-intensity, Low-momentum Muon Beam for the Generation of Low-energy Muons at PSI

    Energy Technology Data Exchange (ETDEWEB)

    Prokscha, T., E-mail: thomas.prokscha@psi.ch; Morenzoni, E.; Deiters, K.; Foroughi, F.; George, D.; Kobler, R.; Vrankovic, V. [Paul Scherrer Institute, PSI (Switzerland)

    2004-12-15

    At the Paul Scherrer Institute (PSI, Villigen, Switzerland) a new high-intensity muon beam line with momentum p < 40 MeV/c is currently being commissioned. The beam line is especially designed to serve the needs of the low-energy, polarized positive muon source (LE-{mu}{sup +}) and LE-{mu} SR spectrometer at PSI. The beam line replaces the existing {mu} E4 muon decay channel. A large acceptance is accomplished by installing two solenoidal magnetic lenses close to the muon production target E that is hit by the 590-MeV PSI proton beam. The muons are then transported by standard large aperture quadrupoles and bending magnets to the experiment. Several slit systems and an electrostatic separator allow the control of beam shape, momentum spread, and to reduce the background due to beam positrons or electrons. Particle intensities of up to 3.5 x 10{sup 8} {mu}{sup +}/s and 10{sup 7} {mu}{sup -}/s are expected at 28 MeV/c beam momentum and 1.8 mA proton beam current. This will translate into a LE-{mu}{sup +} rate of 7,000/s being available at the LE-{mu} SR spectrometer, thus achieving {mu}{sup +} fluxes, that are comparable to standard {mu} SR facilities.

  7. High intensity uranium beams from the superHILAC and the bevatron: final report

    Energy Technology Data Exchange (ETDEWEB)

    1982-03-01

    The two injectors formerly used at the SuperHILAC were a 750-kV air-insulated Cockcroft-Walton (EVE) and a 2.5-MV pressurized HV multiplier (ADAM). The EVE injector can deliver adequate intensities of ions up to mass 40 (argon). The ADAM injector can accelerate ions with lower charge-to-mass ratios, and they can produce beams of heavier ions. The intensity of these beams decreases as the mass number increases, with the lowest practical intensity being achieved with lead beams. Experience with the two existing injectors provided substantial help in defining the general requirements for a new injector which would provide ample beams above mass 40. The requirements for acceptance by the first tank of the SuperHILAC are a particle velocity ..beta.. = 0.0154 (corresponding to an energy of 113 keV/amu) and a charge-to-mass ratio of 0.046 or larger. Present ion source performance dictates an air-insulated Cockcroft-Walton as a pre-accelerator because of its easy accessibility and its good overall reliability. The low charge state ions then receive further acceleration and, if necessary, subsequent stripping to the required charge state before injection into the SuperHILAC. A low-beta linac of the Widereoe type has been built to perform this acceleration. The injector system described consists of a Cockcroft-Walton pre-injector, injection beam lines and isotope analysis, a low-velocity linear accelerator, and SuperHILAC control center modifications.

  8. High intensity multi beam design of SANS instrument for Dhruva reactor

    Science.gov (United States)

    Abbas, Sohrab; Désert, S.; Aswal, V. K.

    2016-05-01

    A new and versatile design of Small Angle Neutron Scattering (SANS) instrument based on utilization of multi-beam is presented. The multi-pinholes and multi-slits as SANS collimator for medium flux Dhruva rearctor have been proposed and their designs have been validated using McStas simulations. Various instrument configurations to achieve different minimum wave vector transfers in scattering experiments are envisioned. These options enable smooth access to minimum wave vector transfers as low as ~ 6×10-4 Å-1 with a significant improvement in neutron intensity, allowing faster measurements. Such angularly well defined and intense neutron beam will allow faster SANS studies of agglomerates larger than few tens of nm.

  9. Ionization chambers for monitoring in high-intensity charged particle beams

    CERN Document Server

    McDonald, J; Viren, B; Diwan, M; Erwin, A R; Naples, D; Ping, H

    2003-01-01

    Radiation-hard ionization chambers were tested using an intense electron beam from the accelerator test facility at the Brookhaven National Laboratory. The detectors were designed to be used as the basic element for monitoring muons in the Main Injector Neutrino beamline at the Fermi National Accelerator Laboratory. Measurements of linearity of response, voltage dependence, and the onset of ionization saturation as a function of gap voltage were performed.

  10. Beam commission of the high intensity proton source developed at INFN-LNS for the European Spallation Source

    Science.gov (United States)

    Neri, L.; Celona, L.; Gammino, S.; Miraglia, A.; Leonardi, O.; Castro, G.; Torrisi, G.; Mascali, D.; Mazzaglia, M.; Allegra, L.; Amato, A.; Calabrese, G.; Caruso, A.; Chines, F.; Gallo, G.; Longhitano, A.; Manno, G.; Marletta, S.; Maugeri, A.; Passarello, S.; Pastore, G.; Seminara, A.; Spartà, A.; Vinciguerra, S.

    2017-07-01

    At the Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS) the beam commissioning of the high intensity Proton Source for the European Spallation Source (PS-ESS) started in November 2016. Beam stability at high current intensity is one of the most important parameter for the first steps of the ongoing commissioning. Promising results were obtained since the first source start with a 6 mm diameter extraction hole. The increase of the extraction hole to 8 mm allowed improving PS-ESS performances and obtaining the values required by the ESS accelerator. In this work, extracted beam current characteristics together with Doppler shift and emittance measurements are presented, as well as the description of the next phases before the installation at ESS in Lund.

  11. Laser-energy transfer and enhancement of plasma waves and electron beams by interfering high-intensity laser pulses.

    Science.gov (United States)

    Zhang, P; Saleh, N; Chen, S; Sheng, Z M; Umstadter, D

    2003-11-28

    The effects of interference due to crossed laser beams were studied experimentally in the high-intensity regime. Two ultrashort (400 fs), high-intensity (4 x 10(17) and 1.6 x 10(18) W/cm(2)) and 1 microm wavelength laser pulses were crossed in a plasma of density 4 x 10(19) cm(3). Energy was observed to be transferred from the higher-power to the lower-power pulse, increasing the amplitude of the plasma wave propagating in the direction of the latter. This results in increased electron self-trapping and plasma-wave acceleration gradient, which led to an increased number of hot electrons (by 300%) and hot-electron temperature (by 70%) and a decreased electron-beam divergence angle (by 45%), as compared with single-pulse illumination. Simulations reveal that increased stochastic heating of electrons may have also contributed to the electron-beam enhancement.

  12. High-intensity ion sources for accelerators with emphasis on H-beam formation and transport

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Roderich [Los Alamos National Laboratory

    2009-01-01

    This paper lays out the fundamental working principles of a variety of high-current ion sources for accelerators in a tutorial manner, and gives examples of specific source types such as d. c. discharge- and rf-driven multicusp sources. Penning-type and ECR-based sources while discussing those principles, pointing out general performance limits as well as the performance parameters of specific sources. Laser-based, two-chamber-. and surface-ionization sources are briefly mentioned. Main aspects of this review are particle feed. ionization mechanism, beam formation and beam transport. Issues seen with beam formation and low-energy transport of negative hydrogen-ion beams are treated in detail.

  13. Intense beam production of highly charged heavy ions by the superconducting electron cyclotron resonance ion source SECRAL.

    Science.gov (United States)

    Zhao, H W; Sun, L T; Zhang, X Z; Guo, X H; Cao, Y; Lu, W; Zhang, Z M; Yuan, P; Song, M T; Zhao, H Y; Jin, T; Shang, Y; Zhan, W L; Wei, B W; Xie, D Z

    2008-02-01

    There has been increasing demand to provide higher beam intensity and high enough beam energy for heavy ion accelerator and some other applications, which has driven electron cyclotron resonance (ECR) ion source to produce higher charge state ions with higher beam intensity. One of development trends for highly charged ECR ion source is to build new generation ECR sources by utilization of superconducting magnet technology. SECRAL (superconducting ECR ion source with advanced design in Lanzhou) was successfully built to produce intense beams of highly charged ion for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28 GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. An innovative design of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28 GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. During the commissioning phase at 18 GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5 kW by two 18 GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810 e microA of O(7+), 505 e microA of Xe(20+), 306 e microA of Xe(27+), and so on. The effect of the magnetic field configuration on the ion source performance has been studied experimentally. SECRAL has been put into operation to provide highly charged ion beams for HIRFL facility since May 2007.

  14. HiRadMat at CERN/SPS - A dedicated facility providing high intensity beam pulses to material samples

    CERN Multimedia

    Charitonidis, N; Efthymiopoulos, I

    2014-01-01

    HiRadMat (High Radiation to Materials), constructed in 2011, is a facility at CERN designed to provide high‐intensity pulsed beams to an irradiation area where material samples as well as accelerator component assemblies (e.g. vacuum windows, high power beam targets, collimators…) can be tested. The facility uses a 440 GeV proton beam extracted from the CERN SPS with a pulse length of up to 7.2 us, and with a maximum pulse energy of 3.4 MJ (3xE13 proton/pulse). In addition to protons, ion beams with energy of 440 GeV/charge and total pulse energy of 21 kJ can be provided. The beam parameters can be tuned to match the needs of each experiment. HiRadMat is not an irradiation facility where large doses on equipment can be accumulated. It is rather a test area designed to perform single pulse experiments to evaluate the effect of high‐intensity pulsed beams on materials or accelerator component assemblies in a controlled environment. The fa‐ cility is designed for a maximum of 1E16 protons per year, dist...

  15. Tailoring of Highly Intense THz Radiation Through High Brightness Electron Beams Longitudinal Manipulation

    Directory of Open Access Journals (Sweden)

    Flavio Giorgianni

    2016-02-01

    Full Text Available The ultra-short electron beams, produced through the velocity bunching compression technique at the SPARC_LAB test Facility (Frascati, Italy, are used to produce Coherent Transition Radiation in the terahertz (THz range. This paper reports on the main features of this THz source, which have a spectral coverage up to 5 THz, a pulse duration down to 100 fs, and an energy per pulse on the order of tens of μJ. These figures of merits open the possibility to apply this source for nonlinear and THz pump-probe experiments in Solid-State Physics and material science.

  16. Thermal effects generated by high-intensity focused ultrasound beams at normal incidence to a bone surface.

    Science.gov (United States)

    Nell, Diane M; Myers, Matthew R

    2010-01-01

    Experiments and computations were performed to study factors affecting thermal safety when high-intensity focused ultrasound (HIFU) beams are normally incident (i.e., beam axis normal to the interface) upon a bone/soft-tissue interface. In particular, the temperature rise and thermal dose were determined as a function of separation between the beam focus and the interface. Under conditions representative of clinical HIFU procedures, it was found that the thermal dose at the bone surface can exceed the threshold for necrosis even when the beam focus is more than 4 cm from the bone. Experiments showed that reflection of the HIFU beam from the bone back into the transducer introduced temperature fluctuations of as much as +/-15% and may be an important consideration for safety analyses at sufficiently high acoustic power. The applicability of linear propagation models in predicting thermal dose near the interface was also addressed. Linear models, while underpredicting thermal dose at the focus, provided a conservative (slight overprediction) estimate of thermal dose at the bone surface. Finally, temperature rise due to absorption of shear waves generated by the HIFU beam in the bone was computed. Modeling shear-wave propagation in the thermal analysis showed that the predicted temperature rise off axis was as much as 30% higher when absorption of shear waves is included, indicating that enhanced heating due to shear-wave absorption is potentially important, even for normally incident HIFU beams.

  17. Beam Dynamics Studies and the Design, Fabrication and Testing of Superconducting Radiofrequency Cavity for High Intensity Proton Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Saini, Arun [Univ. of Delhi, New Delhi (India)

    2012-03-01

    The application horizon of particle accelerators has been widening significantly in recent decades. Where large accelerators have traditionally been the tools of the trade for high-energy nuclear and particle physics, applications in the last decade have grown to include large-scale accelerators like synchrotron light sources and spallation neutron sources. Applications like generation of rare isotopes, transmutation of nuclear reactor waste, sub-critical nuclear power, generation of neutrino beams etc. are next area of investigation for accelerator scientific community all over the world. Such applications require high beam power in the range of few mega-watts (MW). One such high intensity proton beam facility is proposed at Fermilab, Batavia, US, named as Project-X. Project-X facility is based on H- linear accelerator (linac), which will operate in continuous wave (CW) mode and accelerate H- ion beam with average current of 1 mA from kinetic energy of 2.5 MeV to 3 GeV to deliver 3MW beam power. One of the most challenging tasks of the Project-X facility is to have a robust design of the CW linac which can provide high quality beam to several experiments simultaneously. Hence a careful design of linac is important to achieve this objective.

  18. Evolution of High Intensity Beams in the CERN PS Booster after H⁻ Injection and Phase Space Painting

    CERN Document Server

    Cieslak-Kowalska, Magdalena; Benedetto, Elena; Bracco, Chiara

    2016-01-01

    With the LHC Injector Upgrade (LIU) project, the injection energy of PS Booster (PSB) ' first circular accelerator in the LHC injector chain ' will be raised from 50 MeV to 160 MeV and the present multiturn injection will be upgraded to H⁻ injection with transverse and longitudinal painting. In the scope of this project, it is planned to double the beam intensities, profiting from the fact that the βγ2 factor will be two times larger (0.35 at 50 MeV and 0.71 at 160 MeV), so the resulting tune spread driven by a direct space charge should remain similar. This paper describes the feasibility to double the intensity of high intensity and large emittance beams, looking into the evolution under space charge and taking into account losses constrains in the ring and in the extraction lines.

  19. Generation of initial Vlasov distributions for simulation of charged particle beams with high space-charge intensity

    Energy Technology Data Exchange (ETDEWEB)

    Lund, S M; Kikuchi, T; Davidson, R C

    2007-04-12

    Self-consistent Vlasov simulations of beams with high space-charge intensity often require specification of initial phase-space distributions that reflect properties of a beam that is well adapted to the transport channel, both in terms of low-order rms (envelope) properties as well as the higher-order phase-space structure. Here, we first review broad classes of distributions commonly in use as initial Vlasov distributions in simulations of beams with intense space-charge fields including: the Kapchinskij-Vladimirskij (KV) equilibrium, continuous-focusing equilibria with specific detailed examples, and various non-equilibrium distributions, such as the semi-Gaussian distribution and distributions formed from specified functions of linear-field Courant-Snyder invariants. Important practical details necessary to specify these distributions in terms of usual accelerator inputs are presented in a unified format. Building on this presentation, a new class of approximate initial distributions are constructed using transformations that preserve linear-focusing single-particle Courant-Snyder invariants to map initial continuous-focusing equilibrium distributions to a form more appropriate for non-continuous focusing channels. Self-consistent particle-in-cell simulations are employed to show that the approximate initial distributions generated in this manner are better adapted to the focusing channels for beams with high space-charge intensity. This improved capability enables simulation applications that more precisely probe intrinsic stability properties and machine performance.

  20. Generation of Initial Kinetic Distributions for Simulation of Long-Pulse Charged Particle Beams with High Space-Charge intensity

    Energy Technology Data Exchange (ETDEWEB)

    Lund, Steven M.; Kikuchi, Takashi; Davidson, Ronald C.

    2007-04-03

    Self-consistent Vlasov-Poisson simulations of beams with high space-charge intensity often require specification of initial phase-space distributions that reflect properties of a beam that is well adapted to the transport channel--both in terms of low-order rms (envelope) properties as well as the higher-order phase-space structure. Here, we first review broad classes of kinetic distributions commonly in use as initial Vlasov distributions in simulations of unbunched or weakly bunched beams with intense space-charge fields including: the Kapchinskij-Vladimirskij (KV) equilibrium, continuous-focusing equilibria with specific detailed examples, and various non-equilibrium distributions, such as the semi-Gaussian distribution and distributions formed from specified functions of linear-field Courant-Snyder invariants. Important practical details necessary to specify these distributions in terms of usual accelerator inputs are presented in a unified format. Building on this presentation, a new class of approximate initial kinetic distributions are constructed using transformations that preserve linear-focusing single-particle Courant-Snyder invariants to map initial continuous-focusing equilibrium distributions to a form more appropriate for non-continuous focusing channels. Self-consistent particle-in-cell simulations are employed to show that the approximate initial distributions generated in this manner are better adapted to the focusing channels for beams with high space-charge intensity. This improved capability enables simulation applications that more precisely probe intrinsic stability properties and machine performance.

  1. The clinical potential of high energy, intensity and energy modulated electron beams optimized by simulated annealing for conformal radiation therapy

    Science.gov (United States)

    Salter, Bill Jean, Jr.

    Purpose. The advent of new, so called IVth Generation, external beam radiation therapy treatment machines (e.g. Scanditronix' MM50 Racetrack Microtron) has raised the question of how the capabilities of these new machines might be exploited to produce extremely conformal dose distributions. Such machines possess the ability to produce electron energies as high as 50 MeV and, due to their scanned beam delivery of electron treatments, to modulate intensity and even energy, within a broad field. Materials and methods. Two patients with 'challenging' tumor geometries were selected from the patient archives of the Cancer Therapy and Research Center (CTRC), in San Antonio Texas. The treatment scheme that was tested allowed for twelve, energy and intensity modulated beams, equi-spaced about the patient-only intensity was modulated for the photon treatment. The elementary beams, incident from any of the twelve allowed directions, were assumed parallel, and the elementary electron beams were modeled by elementary beam data. The optimal arrangement of elementary beam energies and/or intensities was optimized by Szu-Hartley Fast Simulated Annealing Optimization. Optimized treatment plans were determined for each patient using both the high energy, intensity and energy modulated electron (HIEME) modality, and the 6 MV photon modality. The 'quality' of rival plans were scored using three different, popular objective functions which included Root Mean Square (RMS), Maximize Dose Subject to Dose and Volume Limitations (MDVL - Morrill et. al.), and Probability of Uncomplicated Tumor Control (PUTC) methods. The scores of the two optimized treatments (i.e. HIEME and intensity modulated photons) were compared to the score of the conventional plan with which the patient was actually treated. Results. The first patient evaluated presented a deeply located target volume, partially surrounding the spinal cord. A healthy right kidney was immediately adjacent to the tumor volume, separated

  2. Intercostal high intensity focused ultrasound for liver ablation : The influence of beam shaping on sonication efficacy and near-field risks

    NARCIS (Netherlands)

    de Greef, M.; Schubert, G.; Wijlemans, J. W.; Koskela, J.; Bartels, L. W.; Moonen, C. T. W.; Ries, M.

    2015-01-01

    Purpose: One of the major issues in high intensity focused ultrasound ablation of abdominal lesions is obstruction of the ultrasound beam by the thoracic cage. Beam shaping strategies have been shown by several authors to increase focal point intensity while limiting rib exposure. However, as rib ob

  3. High energy density physics with intense ion and laser beams. Annual report 2003

    Energy Technology Data Exchange (ETDEWEB)

    Weyrich, K. (comp.)

    2004-07-01

    The following topics are dealt with: Laser plasma physics, plasma spectroscopy, beam interaction experiments, atomic and radiation physics, pulsed power applications, beam transport and accelerator research and development, properties of dense plasma, instabilities in beam-plasma interaction, beam transport in dense plasmas, short-pulse laser-matter interaction. (HSI)

  4. Radiative trapping in intense laser beams

    Science.gov (United States)

    Kirk, J. G.

    2016-08-01

    The dynamics of electrons in counter-propagating, circularly polarized laser beams are shown to exhibit attractors whose ability to trap particles depends on the ratio of the beam intensities and a single parameter describing radiation reaction. Analytical expressions are found for the underlying limit cycles and the parameter range in which they are stable. In high-intensity optical pulses, where radiation reaction strongly modifies the trajectories, the production of collimated gamma-rays and the initiation of non-linear cascades of electron-positron pairs can be optimized by a suitable choice of the intensity ratio.

  5. Radiative trapping in intense laser beams

    CERN Document Server

    Kirk, J G

    2016-01-01

    The dynamics of electrons in counter-propagating, circularly polarized laser beams are shown to exhibit attractors whose ability to trap particles depends on the ratio of the beam intensities and a single parameter describing radiation reaction. Analytical expressions are found for the underlying limit cycles and the parameter range in which they are stable. In high-intensity optical pulses, where radiation reaction strongly modifies the trajectories, the production of collimated gamma-rays and the initiation of non-linear cascades of electron-positron pairs can be optimized by a suitable choice of the intensity ratio.

  6. Intense high-frequency gyrotron-based microwave beams for material processing

    Energy Technology Data Exchange (ETDEWEB)

    Hardek, T.W.; Cooke, W.D.; Katz, J.D.; Perry, W.L.; Rees, D.E.

    1997-03-01

    Microwave processing of materials has traditionally utilized frequencies in the 0.915 and 2.45 GHz regions. Microwave power sources are readily available at these frequencies but the relatively long wavelengths can present challenges in uniformly heating materials. An additional difficulty is the poor coupling of ceramic based materials to the microwave energy. Los Alamos National Laboratory scientists, working in conjunction with the National Center for Manufacturing Sciences (NCMS), have assembled a high-frequency demonstration processing facility utilizing gyrotron based RF sources. The facility is primarily intended to demonstrate the unique features available at frequencies as high as 84 GHz. The authors can readily provide quasi-optical, 37 GHz beams at continuous wave (CW) power levels in the 10 kW range. They have also provided beams at 84 GHz at 10 kW CW power levels. They are presently preparing a facility to demonstrate the sintering of ceramics at 30 GHz. This paper presents an overview of the present demonstration processing facility and describes some of the features they have available now and will have available in the near future.

  7. A 13.56 MHz multicusp ion source for high intensity Ar beam

    Science.gov (United States)

    Boonyawan, D.; Chirapatpimol, N.; Sanguansak, N.; Vilaithong, T.

    2000-02-01

    A 13.56 MHz radio frequency (rf) inductively coupled multicusp ion source has been developed for producing an intense argon beam with current density in excess of 30 mA cm-2. The source chamber is a 10 cm diam aluminum cylinder surrounded by 20 rows of 3.5 kG Sm-Co5 magnets which form a longitudinal line-cusp field configuration. The rf antenna coil, placed inside the source chamber, is made of a braided wire threaded through a two turn pyrex tube 6 cm in diameter to prevent electrical leakage and ion sputtering. A 10:1 turns-ratio matching transformer is used to match the 50 Ω output impedance of the rf generator to the impedance of the plasma load. Preliminary measurements were carried out with a single- and four-hole aperture extracting system using argon gas. For single-hole extraction with pressure at 5 mTorr and rf power at 500 W, the ion current density was 27 mA cm-2. Under the same operating condition, a four-hole extracting system could achieve almost the same amount of current density of 25 mA cm-2.

  8. Design Optimisation of a High Intensity Beam Facility and Feasibility Experiment of a Solid Fragmented Target

    CERN Document Server

    Charitonidis, Nikolaos; Rivkin, Leonid

    2014-06-13

    The present PhD thesis describes the design, execution and results of the HRMT-10 experiment performed at the HiRadMat facility of the CERN/SPS complex. The first part of the thesis covers the design optimization studies of the HiRadMat facility, focusing in particular on the radiation protection issues. A detailed Monte-Carlo model of the facility has been developed and validated through comparison with measurements. A very satisfactory agreement between the simulation and the experimental data is observed. In the second part of this thesis, a novel feasibility experiment of a fragmented solid target for a future Neutrino Factory or a Super Beam facility, able to support high beam powers ( 1 MW) is presented in detail. A solid granular target has been proposed as an interesting alternative to an open Hg jet target, presently considered as the baseline for such facilities, but posing considerable technical challenges. The HRMT-10 experiment seeks to address the lack of experimental data of the feasibility of...

  9. Ion beam enhancement in magnetically insulated ion diodes for high-intensity pulsed ion beam generation in non-relativistic mode

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, X. P. [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116024 (China); Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Zhang, Z. C.; Lei, M. K., E-mail: surfeng@dlut.edu.cn [Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Pushkarev, A. I. [Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Laboratory of Beam and Plasma Technology, High Technologies Physics Institute, Tomsk Polytechnic University, 30, Lenin Ave, 634050 Tomsk (Russian Federation)

    2016-01-15

    High-intensity pulsed ion beam (HIPIB) with ion current density above Child-Langmuir limit is achieved by extracting ion beam from anode plasma of ion diodes with suppressing electron flow under magnetic field insulation. It was theoretically estimated that with increasing the magnetic field, a maximal value of ion current density may reach nearly 3 times that of Child-Langmuir limit in a non-relativistic mode and close to 6 times in a highly relativistic mode. In this study, the behavior of ion beam enhancement by magnetic insulation is systematically investigated in three types of magnetically insulated ion diodes (MIDs) with passive anode, taking into account the anode plasma generation process on the anode surface. A maximal enhancement factor higher than 6 over the Child-Langmuir limit can be obtained in the non-relativistic mode with accelerating voltage of 200–300 kV. The MIDs differ in two anode plasma formation mechanisms, i.e., surface flashover of a dielectric coating on the anode and explosive emission of electrons from the anode, as well as in two insulation modes of external-magnetic field and self-magnetic field with either non-closed or closed drift of electrons in the anode-cathode (A-K) gap, respectively. Combined with ion current density measurement, energy density characterization is employed to resolve the spatial distribution of energy density before focusing for exploring the ion beam generation process. Consistent results are obtained on three types of MIDs concerning control of neutralizing electron flows for the space charge of ions where the high ion beam enhancement is determined by effective electron neutralization in the A-K gap, while the HIPIB composition of different ion species downstream from the diode may be considerably affected by the ion beam neutralization during propagation.

  10. Devices for high precision x-ray beam intensity monitoring on BSRF

    CERN Document Server

    Hua-Peng, LI; Zhao, Yi-Dong; Zheng, Lei; Liu, Shu-Hu; Zhao, Xiao-Liang; Zhao, Ya-Shuai

    2016-01-01

    Synchrotron radiation with the characteristic of high brilliance, high level of polarization, high collimation, low emittance and wide tunability in energy has been used as a standard source in metrology(1, 2). For a decade, lots of calibration work have been done on 4B7A in Beijing Synchrotron Radiation Facility (BSRF) (3, 4). For the calibration process, a high-precision online monitor is indispensable. To control the uncertainty under 0.1%, we studied different sizes parallel ion chambers with rare-gas and used different collecting methods to monitor the x-ray intensity of the beamline. Two methods to collect the signal of the ion chambers: reading the current directly with electrometer or signal amplification to collect the counts were compared.

  11. Effect of Power Losses on Self-Focusing of High Intensity Laser Beam in Gases

    CERN Document Server

    Semak, V V

    2013-01-01

    A theoretical study of power loss from periphery of an ultrashort pulse laser beam and temporally resolved defocussing produced by laser induced plasma are performed using paraxial approximation. Our analysis incorporate consideration of spatial distribution of the laser beam irradiance and the results show that substantial power losses (10%-80%) occur from the beam periphery limiting length of a filament. It was also shown that generally accepted concept of self-focusing critical power is inconsistent with consideration of self-induced refraction of spatially distributed laser beam. A new criterion for self-focusing and hypothesis for multiple filamentation are proposed.

  12. Transverse beam shape measurements of intense proton beams using optical transition radiation

    Energy Technology Data Exchange (ETDEWEB)

    Scarpine, Victor E.; /Fermilab

    2012-03-01

    A number of particle physics experiments are being proposed as part of the Department of Energy HEP Intensity Frontier. Many of these experiments will utilize megawatt level proton beams onto targets to form secondary beams of muons, kaons and neutrinos. These experiments require transverse size measurements of the incident proton beam onto target for each beam spill. Because of the high power levels, most beam intercepting profiling techniques will not work at full beam intensity. The possibility of utilizing optical transition radiation (OTR) for high intensity proton beam profiling is discussed. In addition, previous measurements of OTR beam profiles from the NuMI beamline are presented.

  13. Area X-ray or UV camera system for high-intensity beams

    Science.gov (United States)

    Chapman, Henry N.; Bajt, Sasa; Spiller, Eberhard A.; Hau-Riege, Stefan , Marchesini, Stefano

    2010-03-02

    A system in one embodiment includes a source for directing a beam of radiation at a sample; a multilayer mirror having a face oriented at an angle of less than 90 degrees from an axis of the beam from the source, the mirror reflecting at least a portion of the radiation after the beam encounters a sample; and a pixellated detector for detecting radiation reflected by the mirror. A method in a further embodiment includes directing a beam of radiation at a sample; reflecting at least some of the radiation diffracted by the sample; not reflecting at least a majority of the radiation that is not diffracted by the sample; and detecting at least some of the reflected radiation. A method in yet another embodiment includes directing a beam of radiation at a sample; reflecting at least some of the radiation diffracted by the sample using a multilayer mirror; and detecting at least some of the reflected radiation.

  14. Simulations On Pair Creation In Collision Of γ-Beams Produced With High Intensity Lasers

    Science.gov (United States)

    Jansen, Oliver; Ribeyre, Xavier; D'Humieres, Emmanuel; Lobet, Mathieu; Jequier, Sophie; Tikhonchuk, Vladimir

    2016-10-01

    Direct production of electron-positron pairs in two photon collisions, the Breit-Wheeler process, is one of the most basic processes in the universe. However, this process has never been directly observed in the laboratory due to the lack of high intensity γ sources. For a feasibility study and for the optimisation of experimental set-ups we developed a high-performance tree-code. Different possible set-ups with MeV photon sources were discussed and compared using collision detection for huge number of particles in a quantum-electrodynamic regime. The authors acknowledge the financial support from the French National Research Agency (ANR) in the framework of ''The Investments for the Future'' programme IdEx Bordeaux - LAPHIA (ANR-10IDEX-03-02)-Project TULIMA.

  15. Shaped Plasma Lenses for Optical Beam Control at High Laser Intensities

    Science.gov (United States)

    Hubbard, R. F.; Palastro, J. P.; Johnson, L. A.; Hafizi, B.; Gordon, D. F.; Penano, J. R.; Helle, M. H.; Kaganovich, D.

    2016-10-01

    A plasma channel is a cylindrical plasma column with an on-axis density minimum. A short plasma channel can focus a laser pulse in much the same manner as a conventional lens or off-axis parabola. If the plasma has an off-axis density maximum (``inverse channel''), it behaves like a negative lens and acts to defocus the pulse. In either case, a shaped plasma lens (SPL) may be placed in the beamline at locations where the laser intensity or fluence is orders of magnitude above the damage threshold for conventional solid optics. When placed after an off-axis parabola, SPLs may provide additional flexibility and spot size control and may also be useful in suppressing laser prepulse. For high power, ultrashort laser pulses, the broad laser bandwidth and extreme intensities produce chromatic and phase aberrations and amplitude distortions that degrade the lens focusing or defocusing performance. Although there have been a few experiments that demonstrate laser pulse focusing by a shaped plasma lens, generation and control of the plasma present significant challenges. Potential applications of SPLs to laser-plasma accelerators will be discussed. Supported by the Naval Research Laboratory Base Program.

  16. Deflection of high-intensity pulsed ion beam in focusing magnetically insulated ion diode with a passive anode

    Science.gov (United States)

    Zhu, X. P.; Zhang, Q.; Ding, L.; Zhang, Z. C.; Yu, N.; Pushkarev, A.; Lei, M. K.

    2016-12-01

    The focused high-intensity pulsed ion beam (HIPIB) of 100 ns order pulse is generated with respect to its spatial stability in two types of magnetically insulated ion diodes (MIDs) with geometrical focusing configuration using the passive anode, i.e., insulation of electrons with an external magnetic-field and a self-magnetic field, respectively. Anode plasma formation for the ion beam generation is based on different processes in the two types of MIDs, as the surface breakdown on the polymer-coated anode operated in the unipolar pulse mode for the external-magnetic field MID and the explosive electron emission on the graphite anode in the bipolar-pulse mode for the self-magnetic field MID. Typical energy density per pulse is in the range of 3-6 J/cm2, at an accelerating voltage of 200-300 kV with a pulse duration of 120-150 ns. The spatial deviations of the HIPIB is evaluated by measuring the energy density distribution by using an infrared diagnostic method considering neutralizing during the ion beam propagation to the focal plane with a spatial resolution of 1 mm. The ion beam deviation is about ±1.5 mm for the external-magnetic field MID and ±2.5 mm for the self-magnetic field MID, leading to a fluctuation in the energy density of 1%-12%, and 9%-27% within a 10 mm range at the focal point, respectively. It is revealed that the displacement of different parts of a beam spot occurs nonsynchronously, mainly attributable to the intrinsic diode processes of plasma generation and expansion, and ion beam extraction from the anode-cathode gap, while the influence of magnetic field in the transportation region is negligible. The ion beam spatial deviation has a major influence on the shot-to-shot stability of ion beam, and it is suggested that the stability can be enhanced via diode process improvement.

  17. High intensity X/γ photon beams for nuclear physics and photonics

    Science.gov (United States)

    Serafini, L.; Alesini, D.; Bacci, N.; Bliss, N.; Cassou, K.; Curatolo, C.; Drebot, I.; Dupraz, K.; Giribono, A.; Petrillo, V.; Palumbo, L.; Vaccarezza, C.; Variola, A.; Zomer, F.

    2016-05-01

    In this manuscript we review the challenges of Compton backscattering sources in advancing photon beam performances in the 1 - 20 MeV energy range, underlining the design criteria bringing to maximum spectral luminosity and briefly describing the main achievements in conceiving and developing new devices (multi-bunch RF cavities and Laser recirculators) for the case of ELI-NP Gamma Beam System (ELI-NP-GBS).

  18. Channeling of multikilojoule high-intensity laser beams in an inhomogeneous plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ivancic, S. [Univ. of Rochester, Rochester, NY (United States); Haberberger, D. [Univ. of Rochester, Rochester, NY (United States); Habara, H. [Osaka Univ., Suita (Japan); Iwawaki, T. [Osaka Univ., Suita (Japan); Anderson, K. S. [Univ. of Rochester, Rochester, NY (United States); Craxton, R. S. [Univ. of Rochester, Rochester, NY (United States); Froula, D. H. [Univ. of Rochester, Rochester, NY (United States); Meyerhofer, D. D. [Univ. of Rochester, Rochester, NY (United States); Stoeckl, C. [Univ. of Rochester, Rochester, NY (United States); Tanaka, K. A. [Osaka Univ., Suita (Japan); Theobald, W. [Univ. of Rochester, Rochester, NY (United States)

    2015-05-01

    Channeling experiments were performed that demonstrate the transport of high-intensity (>10¹⁸ W/cm²), multikilojoule laser light through a millimeter-sized, inhomogeneous (~300-μm density scale length) laser produced plasma up to overcritical density, which is an important step forward for the fast-ignition concept. The background plasma density and the density depression inside the channel were characterized with a novel optical probe system. The channel progression velocity was measured, which agrees well with theoretical predictions based on large scale particle-in-cell simulations, confirming scaling laws for the required channeling laser energy and laser pulse duration, which are important parameters for future integrated fast-ignition channeling experiments.

  19. Tools for simulation of high beam intensity ion accelerators; Simulationswerkzeuge fuer die Berechnung hochintensiver Ionenbeschleuniger

    Energy Technology Data Exchange (ETDEWEB)

    Tiede, Rudolf

    2009-07-09

    A new particle-in-cell space charge routine based on a fast Fourier transform was developed and implemented to the LORASR code. It provides the ability to perform up to several 100 batch run simulations with up to 1 million macroparticles each within reasonable computation time. The new space charge routine was successfully validated in the framework of the European ''High Intensity Pulsed Proton Injectors'' (HIPPI) collaboration: Several static Poisson solver benchmarking comparisons were performed, as well as particle tracking comparisons along the GSI UNILAC Alvarez section. Moreover machine error setting routines and data analysis tools were developed and applied on error studies for the ''Heidelberg Cacer Therapy'' (HICAT) IH-type drift tube linear accelerator (linac), the FAIR Facility Proton Linac and the proposal of a linac for the ''International Fusion Materials Irradiation Facility'' (IFMIF) based on superconducting CH-type structures. (orig.)

  20. Beam intensity upgrade at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Marchionni, A.; /Fermilab

    2006-07-01

    The performance of the Fermilab proton accelerator complex is reviewed. The coming into operation of the NuMI neutrino line and the implementation of slip-stacking to increase the anti-proton production rate has pushed the total beam intensity in the Main Injector up to {approx} 3 x 10{sup 13} protons/pulse. A maximum beam power of 270 kW has been delivered on the NuMI target during the first year of operation. A plan is in place to increase it to 350 kW, in parallel with the operation of the Collider program. As more machines of the Fermilab complex become available with the termination of the Collider operation, a set of upgrades are being planned to reach first 700 kW and then 1.2 MW by reducing the Main Injector cycle time and by implementing proton stacking.

  1. Delivering the world's most intense muon beam

    Science.gov (United States)

    Cook, S.; D'Arcy, R.; Edmonds, A.; Fukuda, M.; Hatanaka, K.; Hino, Y.; Kuno, Y.; Lancaster, M.; Mori, Y.; Ogitsu, T.; Sakamoto, H.; Sato, A.; Tran, N. H.; Truong, N. M.; Wing, M.; Yamamoto, A.; Yoshida, M.

    2017-03-01

    A new muon beam line, the muon science innovative channel, was set up at the Research Center for Nuclear Physics, Osaka University, in Osaka, Japan, using the 392 MeV proton beam impinging on a target. The production of an intense muon beam relies on the efficient capture of pions, which subsequently decay to muons, using a novel superconducting solenoid magnet system. After the pion-capture solenoid, the first 36° of the curved muon transport line was commissioned and the muon flux was measured. In order to detect muons, a target of either copper or magnesium was placed to stop muons at the end of the muon beam line. Two stations of plastic scintillators located upstream and downstream from the muon target were used to reconstruct the decay spectrum of muons. In a complementary method to detect negatively charged muons, the x-ray spectrum yielded by muonic atoms in the target was measured in a germanium detector. Measurements, at a proton beam current of 6 pA, yielded (10.4 ±2.7 )×1 05 muons per watt of proton beam power (μ+ and μ-), far in excess of other facilities. At full beam power (400 W), this implies a rate of muons of (4.2 ±1.1 )×1 08 muons s-1 , among the highest in the world. The number of μ- measured was about a factor of 10 lower, again by far the most efficient muon beam produced. The setup is a prototype for future experiments requiring a high-intensity muon beam, such as a muon collider or neutrino factory, or the search for rare muon decays which would be a signature for phenomena beyond the Standard Model of particle physics. Such a muon beam can also be used in other branches of physics, nuclear and condensed matter, as well as other areas of scientific research.

  2. Large acceptance magnetic focussing horns for production of a high intensity narrow band neutrino beam at the AGS

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, A.; Chimienti, L.; Leonhardt, W.; Monaghan, R.; Ryan, G.; Sandberg, J.; Sims, W.; Smith, G.; Stillman, P.; Thorwarth, H.

    1985-01-01

    A set of two large acceptance (20 to 140 mrad) horns have been designed and built to form a parallel beam of 3 GeV/c pions and kaons for the production of an intense, dichromatic neutrino beam. A set of beam plugs and collimators determined the momentum of the particles which pass through the horns. The cooling and maintenance of the horns and target was a particular concern since they were operated with an incident intensity of over 10/sup 13/ proton/sec. These systems were designed for simplicity, reliability, and easy replacement.

  3. Beam-commissioning study of high-intensity accelerators using virtual accelerator model

    Science.gov (United States)

    Harada, H.; Shigaki, K.; Irie, Y.; Noda, F.; Hotchi, H.; Saha, P. K.; Shobuda, Y.; Sako, H.; Furukawa, K.; Machida, S.

    2009-04-01

    In order to control large-scale accelerators efficiently, a control system with a virtual accelerator model was constructed. The virtual accelerator (VA) is an on-line beam simulator provided with a beam monitor scheme. The VA is based upon the Experimental Physics and Industrial Control System (EPICS) and is configured under the EPICS input/output controller (IOC) in parallel with a real accelerator (RA). Thus, the machine operator can access the parameters of the RA through the channel access client and then feed them to the VA, and vice versa. Such a control scheme facilitates developments of the commissioning tools, feasibility study of the proposed accelerator parameters and examination of the measured accelerator data. This paper describes the beam commissioning results and activities by using the VA at the J-PARC 3-GeV rapid-cycling synchrotron (RCS).

  4. Beam-commissioning study of high-intensity accelerators using virtual accelerator model

    Energy Technology Data Exchange (ETDEWEB)

    Harada, H. [Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima-shi, Hiroshima 739-8526 (Japan)], E-mail: harada@hepl.hiroshima-u.ac.jp; Shigaki, K. [Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima-shi, Hiroshima 739-8526 (Japan); Irie, Y. [Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), Tsukuba-shi, Ibaraki 305-0801 (Japan); Noda, F. [Energy and Environmental Systems Laboratory, Hitachi, Ltd, 7-2-1 Omika-cho, Hitachi-shi, Ibaraki 319-1221 (Japan); Hotchi, H.; Saha, P.K.; Shobuda, Y.; Sako, H. [Japan Proton Accelerator Research Complex, 2-4 Shirane Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Furukawa, K. [Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), Tsukuba-shi, Ibaraki 305-0801 (Japan); Machida, S. [Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11, 0QX (United Kingdom)

    2009-04-21

    In order to control large-scale accelerators efficiently, a control system with a virtual accelerator model was constructed. The virtual accelerator (VA) is an on-line beam simulator provided with a beam monitor scheme. The VA is based upon the Experimental Physics and Industrial Control System (EPICS) and is configured under the EPICS input/output controller (IOC) in parallel with a real accelerator (RA). Thus, the machine operator can access the parameters of the RA through the channel access client and then feed them to the VA, and vice versa. Such a control scheme facilitates developments of the commissioning tools, feasibility study of the proposed accelerator parameters and examination of the measured accelerator data. This paper describes the beam commissioning results and activities by using the VA at the J-PARC 3-GeV rapid-cycling synchrotron (RCS)

  5. Research on ZrO2 Thermal Barrier Coatings Modified by High-Intensity Pulsed Ion Beam

    Institute of Scientific and Technical Information of China (English)

    WV Di; LIU Chen; ZHU Xiao-Peng; LEI Ming-Kai

    2008-01-01

    @@ We report a modification method for ZrO2 thermal barrier coatings (TBCs) by high-intensity pulsed ion beam (HIPIB) irradiation. Based on the temporal and spatial distribution models of the ion beam density detected by Faraday cup in the chamber and the ions accelerating voltage, the energy deposition of the beam ions in ZrO2 is calculated by Monte Carlo method. Taking this time-dependent nonlinear deposited energy as the source term of two-dimensional thermal conduction equation, we obtain the temporal and spatial ablation process of ZrO2 thermal barrier coatings during a pulse time. The top-layer TBC material in thickness of about 0.2μm is ablated by vaporization and the coating in thickness of 1 μm is melted after one shot at the ion current density of 200 A/cm2. This calculation is in reasonable agreement with those measured by HIPIB irradiation experiments.The melted top coat becoming a dense modification layer due to HIPIB irradiation seals the gaps among ZrO2crystal clusters, and hence barrels the direct tunnel of oxygen.

  6. Edge imaging in intense beams

    Directory of Open Access Journals (Sweden)

    S. Bernal

    2002-06-01

    Full Text Available The appearance of rings of charge observed near the edge of beams from high-perveance guns is described with a simple ray tracing technique inspired by the particle-core model. We illustrate the technique, which has no analog in light optics, with examples from experiments employing solenoid focusing of an electron beam. The rings of charge result from the combined effects of external focusing and space-charge forces acting on paraxial fringe particles with relatively large initial transverse velocities. The model is independent of the physical mechanisms responsible for the fringe particles. Furthermore, the focal length for edge imaging in a uniform focusing channel is derived using a linearized trajectory equation for the motion of fringe particles. Counterintuitively, the focal length decreases as the beam current increases.

  7. Multi-concentric-ring open-air ionization chamber for high-intensity X-ray beams

    Science.gov (United States)

    Nariyama, Nobuteru

    2014-11-01

    An ionization chamber with four concentric ring electrodes was used to measure doses of white, 10, 15 and 20 keV synchrotron X-ray beams. The ring-shaped electrodes, which had diameters less than 11.8 mm, collected charges independently only around the beam, excluding strong in-beam charges when the beams passed through a small hole in the electrode centers. As a result, under low saturation voltages, the measured dose rates were confirmed to correlate with the beam intensity when conversion factors calculated with a Monte Carlo code were employed. The influence of the assumed beam sizes and incident positions on the current was almost negligible, with the exception of the incident position dependence at 10 keV.

  8. Production of intense highly charged ion beams by IMP 14.5 GHz electron cyclotron resonance ion source

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new 14.5 GHz Electron Cyclotron Resonance (ECR) ion source has been constructed over the last two years. The source was designed and tested by making use of the latest results from ECR ion source development, such as high mirror magnetic field, large plasma volume, and biased probe. 140μA of O7+, 185μA of Ar11+ and 50 μA of Xe26+ could be produced with a RF power of 800 W. The intense beams of highly charged metallic ions are produced by means of the method of a metal evaporation oven and volatile compound through axial access. The test results are 130μA of Ca11+, 70μA of Ca12+ and 65μA of Fe10+. The ion source has been put into operation for the cyclotron at the Institute of Modern Physics (IMP).

  9. Production of Medical Radioisotopes with High Specific Activity in Photonuclear Reactions with $\\gamma$ Beams of High Intensity and Large Brilliance

    CERN Document Server

    Habs, D

    2010-01-01

    We study the production of radioisotopes for nuclear medicine in $(\\gamma,x{\\rm n}+y{\\rm p})$ photonuclear reactions or ($\\gamma,\\gamma'$) photoexcitation reactions with high flux [($10^{13}-10^{15}$)$\\gamma$/s], small diameter $\\sim (100 \\, \\mu$m$)^2$ and small band width ($\\Delta E/E \\approx 10^{-3}-10^{-4}$) $\\gamma$ beams produced by Compton back-scattering of laser light from relativistic brilliant electron beams. We compare them to (ion,$x$n$ + y$p) reactions with (ion=p,d,$\\alpha$) from particle accelerators like cyclotrons and (n,$\\gamma$) or (n,f) reactions from nuclear reactors. For photonuclear reactions with a narrow $\\gamma$ beam the energy deposition in the target can be managed by using a stack of thin target foils or wires, hence avoiding direct stopping of the Compton and pair electrons (positrons). $(\\gamma,\\gamma')$ isomer production via specially selected $\\gamma$ cascades allows to produce high specific activity in multiple excitations, where no back-pumping of the isomer to the ground st...

  10. Lifetime of anode polymer in magnetically insulated ion diodes for high-intensity pulsed ion beam generation.

    Science.gov (United States)

    Zhu, X P; Dong, Z H; Han, X G; Xin, J P; Lei, M K

    2007-02-01

    Generation of high-intensity pulsed ion beam (HIPIB) has been studied experimentally using polyethylene as the anode polymer in magnetically insulated ion diodes (MIDs) with an external magnetic field. The HIPIB is extracted from the anode plasma produced during the surface discharging process on polyethylene under the electrical and magnetic fields in MIDs, i.e., high-voltage surface breakdown (flashover) with bombardments by electrons. The surface morphology and the microstructure of the anode polymer are characterized using scanning electron microscopy and differential scanning calorimetry, respectively. The surface roughening of the anode polymer results from the explosive release of trapped gases or newly formed gases under the high-voltage discharging, leaving fractured surfaces with bubble formation. The polyethylene in the surface layer degrades into low-molecular-weight polymers such as polyethylene wax and paraffin under the discharging process. Both the surface roughness and the fraction of low molecular polymers apparently increase as the discharging times are prolonged for multipulse HIPIB generation. The changes in the surface morphology and the composition of anode polymer lead to a noticeable decrease in the output of ion beam intensity, i.e., ion current density and diode voltage, accompanied with an increase in instability of the parameters with the prolonged discharge times. The diode voltage (or surface breakdown voltage of polymer) mainly depends on the surface morphology (or roughness) of anode polymers, and the ion current density on the composition of anode polymers, which account for the two stages of anode polymer degradation observed experimentally, i.e., stage I which has a steady decrease of the two parameters and stage II which shows a slow decrease, but with an enhanced fluctuation of the two parameters with increasing pulses of HIPIB generation.

  11. Deposition of Diamond-Like carbon Films by High-Intensity Pulsed Ion Beam Ablation at Various Substrate Temperatures

    Institute of Scientific and Technical Information of China (English)

    梅显秀; 刘振民; 马腾才; 董闯

    2003-01-01

    Diamond-like carbon (DLC) films have been deposited on to Si substrates at substrate temperatures from 25℃to 400 ℃ by a high-intensity pulsed-ion-beam (HIPIB) ablation deposition technique. The formation of DLC is confirmed by Raman spectroscopy. According to an x-ray photoelectron spectroscopy analysis, the concentration of spa carbon in the films is about 40% when the substrate temperature is below 300 ℃. With increasing substrate temperature from 25 ℃ to 400 ℃, the concentration of sp3 carbon decreases from 43% to 8%. In other words,sp3 carbon is graphitized into sp2 carbon when the substrate temperature is above 300 ℃. The results of xray diffraction and atomic force microscopy show that, with increasing the substrate temperature, the surface roughness and the friction coefficient increase, and the microhardness and the residual stress of the films decrease.

  12. High Energy Density Physics Research Using Intense Heavy Ion Beam at FAIR: The HEDgeHOB Program

    Science.gov (United States)

    Tahir, N. A.; Shutov, A.; Piriz, A. R.; Deutsch, C.; Stöhlker, Th.

    2016-03-01

    International project, Facility for Antiprotons and Ion Research (FAIR), has entered in its construction phase at Darmstadt. It is expected that the new powerful heavy ion synchrotron, SIS100 will deliver a strongly bunched intense beam of energetic uranium ions that will provide the scientists with an efficient and novel tool to research High Energy Density (HED) Physics in the laboratory. Over the past 15 years, substantial theoretical work has been done to design numerous experiments that can be done at this facility in this field. This work has resulted in an extensive scientific proposal named HEDgeHOB, that includes experiment proposals addressing various aspects of HED matter, for example, planetary physics, equation of state, hydrodynamic instabilities and others. In this paper we present a summary of this work.

  13. Study of beryllium redeposition under bombardment by high intensity -low energy- hydrogen ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Gureev, V.M.; Guseva, M.I.; Danelyan, L.S. [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation)] [and others

    1998-01-01

    The results of studying the erosion of beryllium under an effect of intense ion fluxes with the energy of 250 eV, at the fluences {approx}10{sup 2}1 cm{sup -2}, at the MAGRAS-stand are given. The operating conditions under which a practically-complete redeposition of the sputtered beryllium upon the target surface were experimentally-realized. A change in the microstructure of a beryllium target under sputtering and redeposition is analyzed. Some technological applications are considered. (author)

  14. Formation of the surface alloys by high-intensity pulsed electron beam irradiation of the coating/substrate system

    Science.gov (United States)

    Ivanov, Yu F.; Petrikova, E. A.; Teresov, A. D.; Krysina, O. V.; Rygina, M. E.

    2015-04-01

    The results of the analysis of the structure and properties of the surface layer of aluminum A7 subjected to alloying by the intense pulsed electron beam melting of the film / substrate system. Fold increase in strength and tribological properties of the modified surface layer due to the formation of submicro - nanoscale multiphase structure have been revealed.

  15. High Intensity High Energy E-Beam Interacting with a Thin Solid State Target First Results at AIRIX

    CERN Document Server

    Caron, Michel; Collignon, David; Hourdin, Laurent; Merle, Eric; Mouillet, Marc; Mouton, Olivier; Noel, Christian; Paradis, Dominique; Pichoff, Nicolas; Pierret, Olivier

    2005-01-01

    AIRIX is a 2 kA, 20 MeV, 60 ns linear accelerator dedicated to X-ray flash radiography. During a regular running phase, the primary electron beam is accelerated to and focused on a high atomic number target in order to generate X-rays by brembtrahlung mainly. The huge energy density deposited into the material is such that temperature rises up to 15000°K and that clusters and particles are violently ejected from the surface. In that mechanism, the backward emission speed can reach 5 km.s-1 and the debris can gradually accumulate and subsequently contaminate some sensitive parts of the machine. In order to protect the whole accelerating line from the detrimental effect of back-ejected particles, we have investigated the technical feasibility of a thin foil implementation upstream the X-ray converter.

  16. Nonlinear perturbative particle simulation studies of the electron-proton two-stream instability in high intensity proton beams

    Directory of Open Access Journals (Sweden)

    Hong Qin

    2003-01-01

    Full Text Available Two-stream instabilities in intense charged particle beams, described self-consistently by the nonlinear Vlasov-Maxwell equations, are studied using a 3D multispecies perturbative particle simulation method. The recently developed Beam Equilibrium, Stability and Transport code is used to simulate the linear and nonlinear properties of the electron-proton (e-p two-stream instability observed in the Proton Storage Ring (PSR experiment for a long, coasting beam. Simulations in a parameter regime characteristic of the PSR experiment show that the e-p instability has a dipole-mode structure, and that the growth rate is an increasing function of beam intensity, but a decreasing function of the longitudinal momentum spread. It is also shown that the instability threshold decreases with increasing fractional charge neutralization and increases with increasing axial momentum spread of the beam particles. In the nonlinear phase, the simulations show that the proton density perturbation first saturates at a relatively low level and subsequently grows to a higher level. Finally, the nonlinear space-charge-induced transverse tune spread, which introduces a major growth-rate reduction effect on the e-p instability, is studied for self-consistent equilibrium populations of protons and electrons.

  17. On the possible use of the MASURCA reactor as a flexible, high-intensity, fast neutron beam facility

    Science.gov (United States)

    Dioni, Luca; Jacqmin, Robert; Sumini, Marco; Stout, Brian

    2017-09-01

    In recent work [1, 2], we have shown that the MASURCA research reactor could be used to deliver a fairly-intense continuous fast neutron beam to an experimental room located next to the reactor core. As a consequence of the MASURCA favorable characteristics and diverse material inventories, the neutron beam intensity and spectrum can be further tailored to meet the users' needs, which could be of interest for several applications. Monte Carlo simulations have been performed to characterize in detail the extracted neutron (and photon) beam entering the experimental room. These numerical simulations were done for two different bare cores: A uranium metallic core (˜30% 235U enriched) and a plutonium oxide core (˜25% Pu fraction, ˜78% 239Pu). The results show that the distinctive resonance energy structures of the two core leakage spectra are preserved at the channel exit. As the experimental room is large enough to house a dedicated set of neutron spectrometry instruments, we have investigated several candidate neutron spectrum measurement techniques, which could be implemented to guarantee well-defined, repeatable beam conditions to users. Our investigation also includes considerations regarding the gamma rays in the beams.

  18. 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.

  19. Wavefront-correction for nearly diffraction-limited focusing of dual-color laser beams to high intensities.

    Science.gov (United States)

    Zhao, Baozhen; Zhang, Jun; Chen, Shouyuan; Liu, Cheng; Golovin, Grigory; Banerjee, Sudeep; Brown, Kevin; Mills, Jared; Petersen, Chad; Umstadter, Donald

    2014-11-03

    We demonstrate wavefront correction of terawatt-peak-power laser beams at two distinct and well-separated wavelengths. Simultaneous near diffraction-limited focusability is achieved for both the fundamental (800 nm) and second harmonic (400 nm) of Ti:sapphire-amplified laser light. By comparing the relative effectiveness of various correction loops, the optimal ones are found. Simultaneous correction of both beams of different color relies on the linear proportionality between their wavefront aberrations. This method can enable two-color experiments at relativistic intensities.

  20. Wave-front correction of high-intensity fs laser beams by using closed-loop adaptive optics system

    Institute of Scientific and Technical Information of China (English)

    WANG; Zhaohua; JIN; Zhan; ZHENG; Jiaan; WANG; Peng; WEI; Zh

    2005-01-01

    We developed an adaptive optics system to correct the wave-front distortion of an intense fs laser beam from our multi-TW laser system, Jiguang II. In this paper, the instruments of the adaptive optical system are described and the experimental results of the closed-loop wave-front correction are presented. A distorted laser wave-front of 20 wavelengths of P-V values was corrected to 0.15 wavelength of P-V values. The beam quality of the laser system varies from 3.5 diffraction limit to 1.5 diffraction limit.

  1. Comparison of cyclotron and linacs for high-intensity-beam applications

    Energy Technology Data Exchange (ETDEWEB)

    Bhatia, T.S.; Jason, A.; Mottershead, C.T. [Los Alamos National Lab., NM (United States); Cooper, R. [Amparo Corp., NM (United States)

    1998-11-01

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goals of this project were three-fold: (1) to understand the current level of cyclotron design expertise especially in the areas of space-charge modeling and simulation codes, (2) to develop a better understanding of the capabilities and limitations of circular machines, especially in the area of current limits, and (3) to stay abreast of the developments at other institutions in the area of high-current circular machines. These goals were partially met especially in the area of code development for the application of linac codes to motion of ions in a circular orbit. The authors were also able to continue their interactions with the other institutions working in this area.

  2. Design of a high-current low-energy beam transport line for an intense D-T/D-D neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xiaolong, E-mail: luxl@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Engineering Research Center for Neutron Application, Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Wang, Junrun [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Engineering Research Center for Neutron Application, Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Zhang, Yu; Li, Jianyi; Xia, Li; Zhang, Jie; Ding, Yanyan; Jiang, Bing; Huang, Zhiwu; Ma, Zhanwen; Wei, Zheng [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Qian, Xiangping; Xu, Dapeng; Lan, Changlin [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Engineering Research Center for Neutron Application, Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Yao, Zeen, E-mail: zeyao@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Engineering Research Center for Neutron Application, Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

    2016-03-01

    An intense D-T/D-D neutron generator is currently being developed at the Lanzhou University. The Cockcroft–Walton accelerator, as a part of the neutron generator, will be used to accelerate and transport the high-current low-energy beam from the duoplasmatron ion source to the rotating target. The design of a high-current low-energy beam transport (LEBT) line and the dynamics simulations of the mixed beam were carried out using the TRACK code. The results illustrate that the designed beam line facilitates smooth transportation of a deuteron beam of 40 mA, and the number of undesired ions can be reduced effectively using two apertures.

  3. Radiation damage and thermal shock response of carbon-fiber-reinforced materials to intense high-energy proton beams

    Science.gov (United States)

    Simos, N.; Zhong, Z.; Ghose, S.; Kirk, H. G.; Trung, L.-P.; McDonald, K. T.; Kotsina, Z.; Nocera, P.; Assmann, R.; Redaelli, S.; Bertarelli, A.; Quaranta, E.; Rossi, A.; Zwaska, R.; Ammigan, K.; Hurh, P.; Mokhov, N.

    2016-11-01

    A comprehensive study on the effects of energetic protons on carbon-fiber composites and compounds under consideration for use as low-Z pion production targets in future high-power accelerators and low-impedance collimating elements for intercepting TeV-level protons at the Large Hadron Collider has been undertaken addressing two key areas, namely, thermal shock absorption and resistance to irradiation damage. Carbon-fiber composites of various fiber weaves have been widely used in aerospace industries due to their unique combination of high temperature stability, low density, and high strength. The performance of carbon-carbon composites and compounds under intense proton beams and long-term irradiation have been studied in a series of experiments and compared with the performance of graphite. The 24-GeV proton beam experiments confirmed the inherent ability of a 3D C/C fiber composite to withstand a thermal shock. A series of irradiation damage campaigns explored the response of different C/C structures as a function of the proton fluence and irradiating environment. Radiolytic oxidation resulting from the interaction of oxygen molecules, the result of beam-induced radiolysis encountered during some of the irradiation campaigns, with carbon atoms during irradiation with the presence of a water coolant emerged as a dominant contributor to the observed structural integrity loss at proton fluences ≥5 ×1020 p /cm2 . The carbon-fiber composites were shown to exhibit significant anisotropy in their dimensional stability driven by the fiber weave and the microstructural behavior of the fiber and carbon matrix accompanied by the presence of manufacturing porosity and defects. Carbon-fiber-reinforced molybdenum-graphite compounds (MoGRCF) selected for their impedance properties in the Large Hadron Collider beam collimation exhibited significant decrease in postirradiation load-displacement behavior even after low dose levels (˜5 ×1018 p cm-2 ). In addition, the

  4. Radiation damage and thermal shock response of carbon-fiber-reinforced materials to intense high-energy proton beams

    Directory of Open Access Journals (Sweden)

    N. Simos

    2016-11-01

    Full Text Available A comprehensive study on the effects of energetic protons on carbon-fiber composites and compounds under consideration for use as low-Z pion production targets in future high-power accelerators and low-impedance collimating elements for intercepting TeV-level protons at the Large Hadron Collider has been undertaken addressing two key areas, namely, thermal shock absorption and resistance to irradiation damage. Carbon-fiber composites of various fiber weaves have been widely used in aerospace industries due to their unique combination of high temperature stability, low density, and high strength. The performance of carbon-carbon composites and compounds under intense proton beams and long-term irradiation have been studied in a series of experiments and compared with the performance of graphite. The 24-GeV proton beam experiments confirmed the inherent ability of a 3D C/C fiber composite to withstand a thermal shock. A series of irradiation damage campaigns explored the response of different C/C structures as a function of the proton fluence and irradiating environment. Radiolytic oxidation resulting from the interaction of oxygen molecules, the result of beam-induced radiolysis encountered during some of the irradiation campaigns, with carbon atoms during irradiation with the presence of a water coolant emerged as a dominant contributor to the observed structural integrity loss at proton fluences ≥5×10^{20}  p/cm^{2}. The carbon-fiber composites were shown to exhibit significant anisotropy in their dimensional stability driven by the fiber weave and the microstructural behavior of the fiber and carbon matrix accompanied by the presence of manufacturing porosity and defects. Carbon-fiber-reinforced molybdenum-graphite compounds (MoGRCF selected for their impedance properties in the Large Hadron Collider beam collimation exhibited significant decrease in postirradiation load-displacement behavior even after low dose levels (∼5×10^{18}

  5. Impact of high energy high intensity proton beams on targets: Case studies for Super Proton Synchrotron and Large Hadron Collider

    CERN Document Server

    Tahir, N A; Shutov, A; Schmidt, R; Piriz, A R

    2012-01-01

    The Large Hadron Collider (LHC) is designed to collide two proton beams with unprecedented particle energy of 7 TeV. Each beam comprises 2808 bunches and the separation between two neighboring bunches is 25 ns. The energy stored in each beam is 362 MJ, sufficient to melt 500 kg copper. Safety of operation is very important when working with such powerful beams. An accidental release of even a very small fraction of the beam energy can result in severe damage to the equipment. The machine protection system is essential to handle all types of possible accidental hazards; however, it is important to know about possible consequences of failures. One of the critical failure scenarios is when the entire beam is lost at a single point. In this paper we present detailed numerical simulations of the full impact of one LHC beam on a cylindrical solid carbon target. First, the energy deposition by the protons is calculated with the FLUKA code and this energy deposition is used in the BIG2 code to study the corresponding...

  6. The effect of high-intensity pulsed ion beam on surface structures of MAO film on magnesium alloy AZ31

    Energy Technology Data Exchange (ETDEWEB)

    Han, X.G.; Zhu, F. [Transportation Equipments and Ocean Engineering College, Dalian Maritime University, Dalian 116026 (China); Zhu, X.P.; Lei, M.K. [Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Xu, J.J., E-mail: jjxu@dlmu.edu.cn [Transportation Equipments and Ocean Engineering College, Dalian Maritime University, Dalian 116026 (China)

    2013-07-15

    Micro-arc oxidation (MAO) films on AZ31 magnesium alloy were modified by high-intensity pulsed ion beam (HIPIB) irradiation with ion energy of 300 keV at 200 A/cm{sup 2} with up to 10 shots. Scanning electron microscopy, X-ray diffractometry and micro-hardness testers were used to characterize the surface properties of the irradiated MAO films. The thickness of remelted layer increased and then decreased, and the maximal value of 10 μm was obtained at 200 A/cm{sup 2} with 5 shots. The phase structure of the ablated surface still consisted of Mg{sub 2}SiO{sub 4} and MgO, which are the same as that of the original ones. Surface roughness of the ablated surface increased and then decreased with the increase of shot number. The surface roughness for the original MAO film is about 2.10 μm, it decreased to 1.18 μm with 1 shot irradiation and then increased to 4.13 μm with irradiation shots up to 10. Correspondingly, the surface energy of the ablated surface augmented, resulting in the tedious decrease of static contact angle from 145.9° for original film to 49.7° for the film with 10 shots. The ablation modification enhanced the continuity and compaction of the MAO films on AZ31 magnesium alloy.

  7. 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.

  8. Formation of silver nanoparticles inside a soda-lime glass matrix in the presence of a high intensity Ar{sup +} laser beam

    Energy Technology Data Exchange (ETDEWEB)

    Niry, M. D.; Khalesifard, H. R. [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Optics Research Center, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Mostafavi-Amjad, J.; Ahangary, A. [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Azizian-Kalandaragh, Y. [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Department of Physics, University of Mohaghegh Ardabili (UMA), P.O. Box 179, Ardabil (Iran, Islamic Republic of)

    2012-02-01

    Formation and motion of the silver nanoparticles inside an ion-exchanged soda-lime glass in the presence of a focused high intensity continuous wave Ar{sup +} laser beam (intensity: 9.2 x 10{sup 4} W/cm{sup 2}) have been studied in here. One-dimensional diffusion equation has been used to model the diffusion of the silver ions into the glass matrix, and a two-dimensional reverse diffusion model has been introduced to explain the motion of the silver clusters and their migration toward the glass surface in the presence of the laser beam. The results of the mentioned models were in agreement with our measurements on thickness of the ion-exchange layer by means of optical microscopy and recorded morphology of the glass surface around the laser beam axis by using a Mirau interferometer. SEM micrographs were used to extract the size distribution of the migrated silver particles over the glass surface.

  9. Formation of silver nanoparticles inside a soda-lime glass matrix in the presence of a high intensity Ar+ laser beam

    Science.gov (United States)

    Niry, M. D.; Mostafavi-Amjad, J.; Khalesifard, H. R.; Ahangary, A.; Azizian-Kalandaragh, Y.

    2012-02-01

    Formation and motion of the silver nanoparticles inside an ion-exchanged soda-lime glass in the presence of a focused high intensity continuous wave Ar+ laser beam (intensity: 9.2 × 104 W/cm2) have been studied in here. One-dimensional diffusion equation has been used to model the diffusion of the silver ions into the glass matrix, and a two-dimensional reverse diffusion model has been introduced to explain the motion of the silver clusters and their migration toward the glass surface in the presence of the laser beam. The results of the mentioned models were in agreement with our measurements on thickness of the ion-exchange layer by means of optical microscopy and recorded morphology of the glass surface around the laser beam axis by using a Mirau interferometer. SEM micrographs were used to extract the size distribution of the migrated silver particles over the glass surface.

  10. Dynamic imaging with a triggered and intensified CCD camera system in a high-intensity neutron beam

    Science.gov (United States)

    Vontobel, P.; Frei, G.; Brunner, J.; Gildemeister, A. E.; Engelhardt, M.

    2005-04-01

    When time-dependent processes within metallic structures should be inspected and visualized, neutrons are well suited due to their high penetration through Al, Ag, Ti or even steel. Then it becomes possible to inspect the propagation, distribution and evaporation of organic liquids as lubricants, fuel or water. The principle set-up of a suited real-time system was implemented and tested at the radiography facility NEUTRA of PSI. The highest beam intensity there is 2×107 cm s, which enables to observe sequences in a reasonable time and quality. The heart of the detection system is the MCP intensified CCD camera PI-Max with a Peltier cooled chip (1300×1340 pixels). The intensifier was used for both gating and image enhancement, where as the information was accumulated over many single frames on the chip before readout. Although, a 16-bit dynamic range is advertised by the camera manufacturers, it must be less due to the inherent noise level from the intensifier. The obtained result should be seen as the starting point to go ahead to fit the different requirements of car producers in respect to fuel injection, lubricant distribution, mechanical stability and operation control. Similar inspections will be possible for all devices with repetitive operation principle. Here, we report about two measurements dealing with the lubricant distribution in a running motorcycle motor turning at 1200 rpm. We were monitoring the periodic stationary movements of piston, valves and camshaft with a micro-channel plate intensified CCD camera system (PI-Max 1300RB, Princeton Instruments) triggered at exactly chosen time points.

  11. Diagnosis of high-intensity pulsed heavy ion beam generated by a novel magnetically insulated diode with gas puff plasma gun.

    Science.gov (United States)

    Ito, H; Miyake, H; Masugata, K

    2008-10-01

    Intense pulsed heavy ion beam is expected to be applied to materials processing including surface modification and ion implantation. For those applications, it is very important to generate high-purity ion beams with various ion species. For this purpose, we have developed a new type of a magnetically insulated ion diode with an active ion source of a gas puff plasma gun. When the ion diode was operated at a diode voltage of about 190 kV, a diode current of about 15 kA, and a pulse duration of about 100 ns, the ion beam with an ion current density of 54 A/cm(2) was obtained at 50 mm downstream from the anode. By evaluating the ion species and the energy spectrum of the ion beam via a Thomson parabola spectrometer, it was confirmed that the ion beam consists of nitrogen ions (N(+) and N(2+)) of energy of 100-400 keV and the proton impurities of energy of 90-200 keV. The purity of the beam was evaluated to be 94%. The high-purity pulsed nitrogen ion beam was successfully obtained by the developed ion diode system.

  12. Commissioning of a compact laser-based proton beam line for high intensity bunches around 10Â MeV

    Science.gov (United States)

    Busold, S.; Schumacher, D.; Deppert, O.; Brabetz, C.; Kroll, F.; Blažević, A.; Bagnoud, V.; Roth, M.

    2014-03-01

    We report on the first results of experiments with a new laser-based proton beam line at the GSI accelerator facility in Darmstadt. It delivers high current bunches at proton energies around 9.6 MeV, containing more than 109 particles in less than 10 ns and with tunable energy spread down to 2.7% (ΔE/E0 at FWHM). A target normal sheath acceleration stage serves as a proton source and a pulsed solenoid provides for beam collimation and energy selection. Finally a synchronous radio frequency (rf) field is applied via a rf cavity for energy compression at a synchronous phase of -90 deg. The proton bunch is characterized at the end of the very compact beam line, only 3 m behind the laser matter interaction point, which defines the particle source.

  13. Commissioning of a compact laser-based proton beam line for high intensity bunches around 10 MeV

    Directory of Open Access Journals (Sweden)

    S. Busold

    2014-03-01

    Full Text Available We report on the first results of experiments with a new laser-based proton beam line at the GSI accelerator facility in Darmstadt. It delivers high current bunches at proton energies around 9.6 MeV, containing more than 10^{9} particles in less than 10 ns and with tunable energy spread down to 2.7% (ΔE/E_{0} at FWHM. A target normal sheath acceleration stage serves as a proton source and a pulsed solenoid provides for beam collimation and energy selection. Finally a synchronous radio frequency (rf field is applied via a rf cavity for energy compression at a synchronous phase of -90  deg. The proton bunch is characterized at the end of the very compact beam line, only 3 m behind the laser matter interaction point, which defines the particle source.

  14. Relation between reflection high-energy electron diffraction specular beam intensity and the surface atomic structure/surface morphology of GaAs(111)B

    Energy Technology Data Exchange (ETDEWEB)

    Chen, P.; Rajkumar, K.C.; Madhukar, A. (Univ. of Southern California, Los Angeles (United States))

    The intensity behavior of the specular beam in reflection high-energy electron diffraction (RHEED) from GaAs(111)B grown by molecular-beam epitaxy (MBE) is investigated for various growth and diffraction conditions. The temporal behavior during the initial growth of a buffer layer is examined at a fixed diffraction condition. Intensity increase is observed during and after the initial stages of buffer layer growth and found to saturate after about 80 monolayer growth. Intensity oscillations are seen starting at different moments of initial growth, the earliest observed after only 14 monolayer growth. These results are used to guide and control GaAs(111)B growths with mirrorlike surface morphology.

  15. Engineering parabolic beams with dynamic intensity profiles.

    Science.gov (United States)

    Ruelas, Adrian; Lopez-Aguayo, Servando; Gutiérrez-Vega, Julio C

    2013-08-01

    We present optical fields formed by superposing nondiffracting parabolic beams with distinct longitudinal wave-vector components, generating light profiles that display intensity fluxes following parabolic paths in the transverse plane. Their propagation dynamics vary depending on the physical mechanism originating interference, where the possibilities include constructive and destructive interference between traveling parabolic beams, interference between stationary parabolic modes, and combinations of these. The dark parabolic region exhibited by parabolic beams permits a straightforward superposition of intensity fluxes, allowing formation of a variety of profiles, which can exhibit circular, elliptic, and other symmetries.

  16. Development of high pressure deuterium gas targets for the generation of intense mono-energetic fast neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Guzek, J. E-mail: jguzek@debeers.co.za; Richardson, K.; Franklyn, C.B.; Waites, A.; McMurray, W.R.; Watterson, J.I.W.; Tapper, U.A.S

    1999-06-01

    Two different technical solutions to the problem of generation of mono-energetic fast neutron beams on the gaseous targets are presented here. A simple and cost-effective design of a cooled windowed gas target system is described in the first part of this paper. It utilises a thin metallic foil window and circulating deuterium gas cooled down to 100 K. The ultimate beam handling capability of such target is determined by the properties of the window. Reliable performance of this gas target system was achieved at 1 bar of deuterium gas, when exposed to a 45 {mu}A beam of 5 MeV deuterons, for periods in excess of 6 h. Cooling of the target gas resulted in increased fast neutron output and improved neutron to gamma-ray ratio. The second part of this paper discusses the design of a high pressure, windowless gas target for use with pulsed, low duty cycle accelerators. A rotating seal concept was applied to reduce the gas load in a differentially pumped system. This allows operation at 1.23 bar of deuterium gas pressure in the gas cell region. Such a gas target system is free from the limitations of the windowed target but special attention has to be paid to the heat dissipation capability of the beam dump, due to the use of a thin target. The rotating seal concept is particularly suitable for use with accelerators such as radio-frequency quadrupole (RFQ) linacs that operate with a very high peak current at low duty cycle. The performance of both target systems was comprehensively characterized using the time-of-flight (TOF) technique. This demonstrated that very good quality mono-energetic fast neutron beams were produced with the slow neutron and gamma-ray component below 10% of the total target output.

  17. LHC Report: reaching high intensity

    CERN Multimedia

    Jan Uythoven

    2015-01-01

    After both beams having been ramped to their full energy of 6.5 TeV, the last two weeks saw the beam commissioning process advancing on many fronts. An important milestone was achieved when operators succeeded in circulating a nominal-intensity bunch. During the operation, some sudden beam losses resulted in beam dumps at top energy, a problem that needed to be understood and resolved.   In 2015 the LHC will be circulating around 2800 bunches in each beam and each bunch will contain just over 1 x 1011 protons. Until a few days ago commissioning was taking place with single bunches of 5 x 109 protons. The first nominal bunch with an intensity of 1 x 1011 protons was injected on Tuesday, 21 April. In order to circulate such a high-intensity bunch safely, the whole protection system must be working correctly: collimators, which protect the aperture, are set at preliminary values known as coarse settings; all kicker magnets for injecting and extracting the beams are commissioned with beam an...

  18. Development of a dedicated beam forming system for material and bioscience research with high intensity, small field electron beam of LILLYPUT 3 accelerator at Wroclaw Technology Park

    CERN Document Server

    Adrich, Przemysław; Wilk, Piotr; Chorowski, Maciej; Poliński, Jarosław; Bogdan, Piotr

    2016-01-01

    The primary use of the LILLYPUT 3 accelerator at the Nondestructive Testing Laboratory at Wroclaw Technology Park is X-ray radiography for nondestructive testing, including R&D of novel techniques for industrial and medical imaging. The scope of possible applications could be greatly extended by providing a system for irradiation with electron beam. The purpose of this work was to design such a system, especially for high dose rate, small field irradiations under cryogenic conditions for material and bioscience research. In this work, two possible solutions, based either on beam scanning or scattering and collimation, were studied and compared. It was found that under existing conditions efficiency of both systems would be comparable. The latter one was adopted due to its simplicity and much lower cost. The system design was optimized by means of detailed Monte Carlo modeling. The system is being currently fabricated at National Centre for Nuclear Research in \\'Swierk.

  19. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole.

    Science.gov (United States)

    Rodrigues, G; Becker, R; Hamm, R W; Baskaran, R; Kanjilal, D; Roy, A

    2014-02-01

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged (238)U(40+) (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  20. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, G., E-mail: gerosro@gmail.com; Kanjilal, D.; Roy, A. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi (India); Becker, R. [Institut fur Angewandte Physik der Universitaet, D-60054 Frankfurt/M (Germany); Hamm, R. W. [R and M Technical Enterprises, Inc., 4725 Arlene Place, Pleasanton, California 94566 (United States); Baskaran, R. [Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamilnadu (India)

    2014-02-15

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged {sup 238}U{sup 40+} (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  1. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole

    Science.gov (United States)

    Rodrigues, G.; Becker, R.; Hamm, R. W.; Baskaran, R.; Kanjilal, D.; Roy, A.

    2014-02-01

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged 238U40+ (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  2. Fan-beam intensity modulated proton therapy

    Science.gov (United States)

    Hill, Patrick; Westerly, David; Mackie, Thomas

    2013-01-01

    Purpose: This paper presents a concept for a proton therapy system capable of delivering intensity modulated proton therapy using a fan beam of protons. This system would allow present and future gantry-based facilities to deliver state-of-the-art proton therapy with the greater normal tissue sparing made possible by intensity modulation techniques. Methods: A method for producing a divergent fan beam of protons using a pair of electromagnetic quadrupoles is described and particle transport through the quadrupole doublet is simulated using a commercially available software package. To manipulate the fan beam of protons, a modulation device is developed. This modulator inserts or retracts acrylic leaves of varying thickness from subsections of the fan beam. Each subsection, or beam channel, creates what effectively becomes a beam spot within the fan area. Each channel is able to provide 0–255 mm of range shift for its associated beam spot, or stop the beam and act as an intensity modulator. Results of particle transport simulations through the quadrupole system are incorporated into the MCNPX Monte Carlo transport code along with a model of the range and intensity modulation device. Several design parameters were investigated and optimized, culminating in the ability to create topotherapy treatment plans using distal-edge tracking on both phantom and patient datasets. Results: Beam transport calculations show that a pair of electromagnetic quadrupoles can be used to create a divergent fan beam of 200 MeV protons over a distance of 2.1 m. The quadrupole lengths were 30 and 48 cm, respectively, with transverse field gradients less than 20 T/m, which is within the range of water-cooled magnets for the quadrupole radii used. MCNPX simulations of topotherapy treatment plans suggest that, when using the distal edge tracking delivery method, many delivery angles are more important than insisting on narrow beam channel widths in order to obtain conformal target coverage

  3. Space-Charge Waves and Instabilities in Intense Beams

    Science.gov (United States)

    Wang, J. G.

    1997-11-01

    Advancced accelerator applications, such as drivers for heavy ion inertial fusion, high-intensity synchrotrons for spallation neutron sources, high energy boosters, free electron lasers, high-power microwave generators, etc., require ever-increasing beam intensity. An important beam dynamics issue in such beams is the collective behavior of charged particles due to their space charge effects. This includes the phenomena of space-charge waves and instabilities excited on beams by external perturbations. It is very crucial to fully understand these phenomena in order to develop advanced accelerators for various applications. At the University of Maryland we have been conducting experimental programs to study space-charge waves and longitudinal instabilities by employing low-energy, high-current, space-charge dominated electron beams. Localized perturbations on the beams are generated from a gridded electron gun. In a conducting transport channel focused by short solenoids, these perturbations evolve into space-charge waves propagating on the beams. The wave speed is measured and many beam parameters are determined with this technique. The reflection of space-charge waves at the shoulder of an initially rectangular beam bunch is also observed. In a resistive-wall channel focused by a uniform long solenoid, the space-charge waves suffer longitudinal instability. The properties of the instabilities are studied in detail in the long wavelength range. In this talk we review our experimental results on the waves and instabilities and compare with theory.

  4. 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.

  5. Linac design for intense hadron beams

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chuan

    2009-12-14

    Based on the RFQ and H-type DTL structures, this dissertation is dedicated to study the beam dynamics in the presence of significantly strong space-charge effects while accelerating intense hadron beams in the low- and medium-{beta} region. Besides the 5 mA/30 mA, 17 MeV proton injector (RFQ+DTL) and the 125 mA, 40 MeV deuteron DTL of the EUROTRANS and IFMIF facilities, a 200 mA, 700 keV proton RFQ has been also intensively studied for a small-scale but ultra-intense neutron source FRANZ planned at Frankfurt University. The most remarkable properties of the FRANZ RFQ and the IFMIF DTL are the design beam intensities, 200 mA and 125 mA. A new design approach, which can provide a balanced and accelerated beam bunching at low energy, has been developed for intense beams. To design the IFMIF DTL and the injector DTL part of the EUROTRANS driver linac, which have been foreseen as the first real applications of the novel superconducting CH-DTL structure, intensive attempts have been made to fulfill the design goals under the new conditions. For the IFMIF DTL, the preliminary IAP design has been considerably improved with respect to the linac layout as well as the beam dynamics. By reserving sufficient drift spaces for the cryosystem, diagnostic devices, tuner and steerer, introducing SC solenoid lenses and adjusting the accelerating gradients and accordingly other configurations of the cavities, a more realistic, reliable and efficient linac system has been designed. On the other hand, the specifications and positions of the transverse focusing elements as well as the phase- and energy-differences between the bunch-center particle and the synchronous particle at the beginning of the {phi}{sub s}=0 sections have been totally redesigned. For the EUROTRANS injector DTL, in addition to the above-mentioned procedures, extra optimization concepts to coordinate the beam dynamics between two intensities have been applied. In the beam transport simulations for both DTL designs

  6. Studies of equation of state properties of high-energy density matter using intense heavy ion beams at the future FAIR facility: The HEDgeHOB collaboration

    Energy Technology Data Exchange (ETDEWEB)

    Tahir, N.A. [Gesellschaft fuer Schwerionenforschung Darmstadt, 64291 Darmstadt (Germany)]. E-mail: n.tahir@gsi.de; Spiller, P. [Gesellschaft fuer Schwerionenforschung Darmstadt, 64291 Darmstadt (Germany); Udrea, S. [Institut fuer Kernphysik, TU Darmstadt, 64289 Darmstadt (Germany); Cortazar, O.D. [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Deutsch, C. [LPGP, Universite Paris-Sud, 91405 Orsay (France); Fortov, V.E. [Institute for Problems in Chemical Physics, Chernogolovka (Russian Federation); Gryaznov, V. [Institute for Problems in Chemical Physics, Chernogolovka (Russian Federation); Hoffmann, D.H.H. [Gesellschaft fuer Schwerionenforschung Darmstadt, 64291 Darmstadt (Germany); Institut fuer Kernphysik, TU Darmstadt, 64289 Darmstadt (Germany); Lomonosov, I.V. [Institute for Problems in Chemical Physics, Chernogolovka (Russian Federation); Ni, P. [Institut fuer Kernphysik, TU Darmstadt, 64289 Darmstadt (Germany); Piriz, A.R. [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Shutov, A. [Institute for Problems in Chemical Physics, Chernogolovka (Russian Federation); Temporal, M. [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Varentsov, D. [Institut fuer Kernphysik, TU Darmstadt, 64289 Darmstadt (Germany)

    2006-04-15

    This paper shows with the help of numerical simulations the capabilities of intense heavy ion beams to induce states of high-energy density (HED) in matter. Two different experimental schemes are considered, namely, HIHEX (heavy ion heating and expansion) and LAPLAS (laboratory planetary sciences). The first scheme considers isochoric heating and subsequent isentropic expansion of matter while the latter deals with low entropy compression of matter using multiple shock reflection technique. This work has been done within the framework of the HEDgeHOB (high-energy density matter generated by heavy ion beams) collaboration that has been formed to organize and facilitate construction of experimental facilities and later to perform experimental work in the field of HED matter at the future FAIR (facility for antiprotons and ion research) facility.

  7. Studies of equation of state properties of high-energy density matter using intense heavy ion beams at the future FAIR facility: The HEDgeHOB collaboration

    Science.gov (United States)

    Tahir, N. A.; Spiller, P.; Udrea, S.; Cortazar, O. D.; Deutsch, C.; Fortov, V. E.; Gryaznov, V.; Hoffmann, D. H. H.; Lomonosov, I. V.; Ni, P.; Piriz, A. R.; Shutov, A.; Temporal, M.; Varentsov, D.

    2006-04-01

    This paper shows with the help of numerical simulations the capabilities of intense heavy ion beams to induce states of high-energy density (HED) in matter. Two different experimental schemes are considered, namely, HIHEX (heavy ion heating and expansion) and LAPLAS (laboratory planetary sciences). The first scheme considers isochoric heating and subsequent isentropic expansion of matter while the latter deals with low entropy compression of matter using multiple shock reflection technique. This work has been done within the framework of the HEDgeHOB (high-energy density matter generated by heavy ion beams) collaboration that has been formed to organize and facilitate construction of experimental facilities and later to perform experimental work in the field of HED matter at the future FAIR (facility for antiprotons and ion research) facility.

  8. Limiting current of intense electron beams in a decelerating gap

    Science.gov (United States)

    Nusinovich, G. S.; Beaudoin, B. L.; Thompson, C.; Karakkad, J. A.; Antonsen, T. M.

    2016-02-01

    For numerous applications, it is desirable to develop electron beam driven efficient sources of electromagnetic radiation that are capable of producing the required power at beam voltages as low as possible. This trend is limited by space charge effects that cause the reduction of electron kinetic energy and can lead to electron reflection. So far, this effect was analyzed for intense beams propagating in uniform metallic pipes. In the present study, the limiting currents of intense electron beams are analyzed for the case of beam propagation in the tubes with gaps. A general treatment is illustrated by an example evaluating the limiting current in a high-power, tunable 1-10 MHz inductive output tube (IOT), which is currently under development for ionospheric modification. Results of the analytical theory are compared to results of numerical simulations. The results obtained allow one to estimate the interaction efficiency of IOTs.

  9. The Evaluation of the Residual Dose Caused by the Large-Angle Foil Scattering Beam Loss for the High Intensity Beam Operation in the J-PARC RCS

    Science.gov (United States)

    Kato, Shinichi; Yamamoto, Kazami; Harada, Hiroyuki; Hotchi, Hideaki; Saha, Pranab K.; Kinsho, Michikazu

    The Japan Proton Accelerator Research Complex 3-GeV rapid cycling synchrotron (RCS) has adopted the multi-turn charge-exchange injection scheme that uses H- beams. During injection, both the injected and circulating beams scatter from the charge-exchange foil. Therefore, the beam loss caused by the large-angle scattering from the foil occurs downstream of the injection point. For countermeasure against the uncontrolled beam loss, a new collimation system was developed and installed in the summer shutdown period in 2011. During beam commissioning, this uncontrolled beam loss was successfully localized for a 300 kW beam. Since the present target power of the RCS is 1 MW, the accurate simulation model to reproduce experimental results has been constructed in order to evaluate residual dose at higher power operation.

  10. Hydrodynamics of evaporating aerosols irradiated by intense laser beams

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, R.L.; Zardecki, A.; Gerstl, S.A.W.

    1985-01-01

    An analysis is presented describing the interactions of atmospheric aerosols with a high-intensity laser beam propagating along an atmospheric path. For the case of moderate beam irradiances, diffusive mass transport and conductive energy transport dominate the aerosol-beam interactions. In this regime, the coupled aerosol-beam equations are solved numerically to obtain the spatic-temporal behavior of the propagating beam, and of the irradiated aerosols. For higher beam irradiances, convective transport of mass, energy and momentum away from the irradiated aerosols must be considered. The hydrodynamic equations are solved in the surrounding medium for this regime subject to appropriate ''jump conditions'' at the surface of the irradiated aerosol. Numerical examples illustrative of both regimes are given for the case of irradiated water aerosol droplets. 11 refs., 6 figs.

  11. Application of Beam Diagnostics for Intense Heavy Ion Beams at the GSI UNILAC

    CERN Document Server

    Barth, W; Glatz, J; Groening, L; Richter, S; Yaramishev, S

    2003-01-01

    With the new High Current Injector (HSI) of the GSI UNILAC the beam pulse intensity had been increased by approximately two orders of magnitudes. The HSI was mounted and commissioned in 1999; since this time the UNILAC serves as an injector for the synchrotron SIS, especially for high uranium intensities. Considering the high beam power of up to 1250 kW and the short stopping range for the UNILAC beam energies (≤12 MeV/u), accelerator components could be destroyed, even during a single beam pulse. All diagnostic elements had to be replaced preferably by non-destructive devices. The beam current is mainly measured by beam transformers instead of Faraday cups, beam positions are measured with segmented capacitive pick-ups and secondary beam monitors instead of profile harps. The 24 installed pick-ups are also used to measure intensities, widths and phase of the bunches, as well beam energies by evaluating pick-ups at different positions. The residual gas ionization monitors allow on-line measurements ...

  12. Numerical study on the thermo-stress of ZrO_2 thermal barrier coatings by high-intensity pulsed ion beam irradiation

    Institute of Scientific and Technical Information of China (English)

    Wu Di; Liu Chen; Zhu Xiao Peng; Lei Ming Kai

    2009-01-01

    This paper studies numerically the thermo-mechanical effects of ZrO_2 thermal barrier coatings (TBCs) irradiated by a high-intensity pulsed ion beam in consideration of the surface structure. Taking the deposited energy of ion beams in TBCs as the source term in the thermal conduction equation, the distribution of temperature in TBCs was simulated. Then, based on the distribution, the evolution of thermal stress was calculated by the finite element method. The results show that tensile radial stress formed at the valley of TBC surfaces after irradiation by HIPIB. Therefore, if cracks happen, they must be at valleys instead of peaks. As for the stress waves, no matter whether through peak or valley position, tensile and compressive stresses are present alternately inside TBCs along the depth direction, and the strength of stress decreases with time.

  13. Strong Radiation-Damping Effects in a Gamma-Ray Source Generated by the Interaction of a High-Intensity Laser with a Wakefield-Accelerated Electron Beam

    Science.gov (United States)

    Thomas, A. G. R.; Ridgers, C. P.; Bulanov, S. S.; Griffin, B. J.; Mangles, S. P. D.

    2012-10-01

    A number of theoretical calculations have studied the effect of radiation-reaction forces on radiation distributions in strong-field counterpropagating electron-beam-laser interactions, but could these effects—including quantum corrections—be observed in interactions with realistic bunches and focusing fields, as is hoped in a number of soon-to-be-proposed experiments? We present numerical calculations of the angularly resolved radiation spectrum from an electron bunch with parameters similar to those produced in laser-wakefield-acceleration experiments, interacting with an intense, ultrashort laser pulse. For our parameters, the effect of radiation damping on the angular distribution and energy distribution of photons is not easily discernible for a realistic moderate-emittance electron beam. However, experiments using such a counterpropagating beam-laser geometry should be able to measure these effects using current laser systems through measurement of the electron-beam properties. In addition, the brilliance of this source is very high, with peak spectral brilliance exceeding 1029photonss-1mm-2mrad-2(0.1%bandwidth)-1 with an approximately 2% conversion efficiency and with a peak energy of 10 MeV.

  14. Strong radiation damping effects in a gamma-ray source generated by the interaction of a high intensity laser with a wakefield accelerated electron beam

    Science.gov (United States)

    Thomas, Alexander; Ridgers, Christopher; Bulanov, Stepan; Griffin, Blake; Mangles, Stuart

    2012-10-01

    We present numerical calculations of the angularly resolved radiation spectrum from a relativistic electron beam interacting with an ultrashort laser pulse. These calculations include the effect of semi-classical radiation reaction forces including a Gaunt factor for synchrotron radiation. For a laser of 5x10^21 Wcm-2 intensity interacting with a 200 MeV electron beam with an emittance similar to that in laser wakefield acceleration experiments, radiation reaction does not produce a significant change in the angular and energy distribution of photons. However the effects of radiation reaction are clear when observing the electron beam properties. The result is that near-term experiments using such a counter-propagating beam-laser geometry should be able to measure the effects of quantum effects in radiation reaction. The calculations also show that the brilliance of this source is very high, with a peak spectral brilliance exceeding 10^29 photons,s-1mm-2mrad-2(0.1% bandwidth)-1 with approximately 2% efficiency and with a peak energy of 10 MeV.

  15. Study of Positronium in Low-k Dielectric Films by means of 2D-Angular Correlation Experiments at a High-Intensity Slow-Positron Beam

    Energy Technology Data Exchange (ETDEWEB)

    Gessmann, T; Petkov, M P; Weber, M H; Lynn, K G; Rodbell, K P; Asoka-Kumar, P; Stoeffl, W; Howell, R H

    2001-06-20

    Depth-resolved measurements of the two-dimensional angular correlation of annihilation radiation (2D-ACAR) were performed at the high-intensity slow-positron beam of Lawrence Livermore National Laboratory. We studied the formation of positronium in thin films of methyl-silsesquioxane (MSSQ) spin-on glass containing open-volume defects in the size of voids. Samples with different average void sizes were investigated and positronium formation could be found in all cases. The width of the angular correlation related to the annihilation of parapositronium increased with the void size indicating the annihilation of non-thermalized parapositronium.

  16. Polarized beams in high energy circular accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Chao, A.W.

    1979-05-01

    In recent years, high energy physicists have become increasingly interested in the possible spin effects at high energies. To study those spin effects, it is desirable to have beams with high energy, high intensity and high polarization. In this talk, we briefly review the present status and the prospects for the near future of high energy polarized beams. 30 refs.

  17. High power, high beam quality regenerative amplifier

    Science.gov (United States)

    Hackel, L.A.; Dane, C.B.

    1993-08-24

    A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

  18. Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Warren, B.

    2012-12-01

    We present results from the grant entitled, Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions. The research significantly advanced the understanding of basic high-energy density science (HEDS) on ultra intense laser and particle beam plasma interactions. This advancement in understanding was then used to to aid in the quest to make 1 GeV to 500 GeV plasma based accelerator stages. The work blended basic research with three-dimensions fully nonlinear and fully kinetic simulations including full-scale modeling of ongoing or planned experiments. The primary tool was three-dimensional particle-in-cell simulations. The simulations provided a test bed for theoretical ideas and models as well as a method to guide experiments. The research also included careful benchmarking of codes against experiment. High-fidelity full-scale modeling provided a means to extrapolate parameters into regimes that were not accessible to current or near term experiments, thereby allowing concepts to be tested with confidence before tens to hundreds of millions of dollars were spent building facilities. The research allowed the development of a hierarchy of PIC codes and diagnostics that is one of the most advanced in the world.

  19. Submicro and Nano Structured Porous Materials for the Production of High-Intensity Exotic Radioactive Ion Beams

    CERN Document Server

    Fernandes, Sandrina; Stora, Thierry

    2010-01-01

    ISOLDE, the CERN Isotope Separator On-line DEvice is a unique source of low energy beams of radioactive isotopes - atomic nuclei that have too many or too few neutrons to be stable. The facility is like a small ‘chemical factory’, giving the possibility of changing one element to another, by selecting the atomic mass of the required isotope beam in the mass separator, rather as the ‘alchemists’ once imagined. It produces a total of more than 1000 different isotopes from helium to radium, with half-lives down to milliseconds, by impinging a 1.4 GeV proton beam from the Proton Synchrotron Booster (PSB) onto special targets, yielding a wide variety of atomic fragments. Different components then extract the nuclei and separate them according to mass. The post-accelerator REX (Radioactive beam EXperiment) at ISOLDE accelerates the radioactive beams up to 3 MeV/u for many experiments. A wide international user radioactive ion beam (RIB) community investigates fundamental aspects of nuclear physics, particle...

  20. CAS course on Intensity Limitations in Particle Beams at CERN

    CERN Multimedia

    CERN Accelerator School

    2015-01-01

    The CERN Accelerator School (CAS) recently organised a specialised course on Intensity Limitations in Particle Beams, at CERN from 2 to 11 November, 2015.     Many accelerators and storage rings, whether intended for particle physics experiments, synchrotron light sources or industrial applications, require beams of high brightness and the highest possible intensities. A good understanding of the possible limitations is required to achieve the desired performance. This course covered the interaction of beams with their surroundings and with other beams, as well as further collective effects. The lectures on the effects and possible mitigations were complemented by tutorials. The course was very successful, with 66 students representing 14 nationalities attending. Most participants came from European counties, but also from Armenia, China and Russia. Feedback from the participants was positive, reflecting the standard of the lectures and teaching. In addition to the academic pro...

  1. First intense isotopic titanium-50 beam using MIVOC method

    Energy Technology Data Exchange (ETDEWEB)

    Rubert, J.; Piot, J. [Departement de Recherches Subatomiques, Institut Pluridisciplinaire Hubert Curien, UMR 7178, Universite de Strasbourg/CNRS-IN-2P-3, 23 rue du Loess, F-67037 Strasbourg (France); Asfari, Z. [Laboratoire d' Ingenierie Moleculaire Appliquee a l' Analyse (DSA), Institut Pluridisciplinaire Hubert Curien, UMR 7178, Universite de Strasbourg/CNRS-IN-2P-3, 23 rue du Loess, F-67037 Strasbourg (France); Gall, B.JP., E-mail: benoit.gall@iphc.cnrs.fr [Departement de Recherches Subatomiques, Institut Pluridisciplinaire Hubert Curien, UMR 7178, Universite de Strasbourg/CNRS-IN-2P-3, 23 rue du Loess, F-67037 Strasbourg (France); Aerje, J. [Department of Physics, University of Jyvaeskylae, P.O. Box 35 (YFL), Jyvaeskylae FI-40014 (Finland); Dorvaux, O. [Departement de Recherches Subatomiques, Institut Pluridisciplinaire Hubert Curien, UMR 7178, Universite de Strasbourg/CNRS-IN-2P-3, 23 rue du Loess, F-67037 Strasbourg (France); Greenlees, P.T.; Koivisto, H. [Department of Physics, University of Jyvaeskylae, P.O. Box 35 (YFL), Jyvaeskylae FI-40014 (Finland); and others

    2012-04-01

    An organometallic compound isotopically enriched in titanium-50 has been successfully used for the first time to produce intense ion beams with an ECR ion source by means of the MIVOC method. After some fruitful tests performed with compounds produced at IPHC Strasbourg with natural titanium, enriched organometallic titanium compound was produced successfully, beam extracted from ECR ion sources and accelerated through a K = 130 MeV cyclotron to an energy of 242 MeV. This isotopic {sup 50}Ti{sup 11{sup +}} beam was used for the first time in three week-experiment with typical MIVOC stable operating conditions. After optimization, up to 19.4 {mu}A of titanium-50 in charge state 11{sup +} could be extracted from the JYFL 14 GHz ECRIS2 ion source. This measurement has demonstrated the possible use of the MIVOC method for production of an intense highly charged isotopic titanium-50 ion beam with rather low material consumption.

  2. A new experimental setup designed for the investigation of irradiation of nanosystems in the gas phase: A high intensity mass-and-energy selected cluster beam

    Energy Technology Data Exchange (ETDEWEB)

    Bruny, G.; Feil, S.; Fillol, R.; El Farkh, K.; Harb, M. M.; Teyssier, C.; Abdoul-Carime, H.; Farizon, B.; Farizon, M. [Institut de Physique Nucleaire de Lyon, UMR5822, Universite Lyon 1, F-69622, Villeurbanne (France); Universite de Lyon, F-69003, Lyon (France) and CNRS/IN2P3, F-69622, Villeurbanne (France); Eden, S. [Department of Physical Sciences, Open University (OU), Walton hall, Milton Keynes, MK76AA (United Kingdom); Ouaskit, S. [Laboratoire de physique de la matiere condensee, Faculte des sciences Ben M' sik, Unite associee au CNRST (URAC 10), B.P.7955, Casablanca (Morocco); Maerk, T. D. [Institut fuer Ionenphysik und Angewandte Physik, Leopold Franzens Universitaet, Technikerstrasse 25, A-6020 Innsbruck (Austria)

    2012-01-15

    DIAM (Dispositif d'Irradiation d'Agregats Moleculaires) is a new experimental setup devoted to investigate processes induced by irradiation at the nanoscale. The DIAM apparatus is based on a combination of techniques including a particle beam from high-energy physics, a cluster source from molecular and cluster physics, and mass spectrometry form analytical sciences. In this paper, we will describe the first part of the DIAM apparatus that consists of an ExB double spectrometer connected to a cluster ion source based on a continuous supersonic expansion in the presence of ionizing electrons. This setup produces high intensities of energy-and-mass selected molecular cluster ion beams (1000 s of counts s{sup -1}). The performance of the instrument will be shown through measurements of 6-8 keV beams of protonated water clusters, (H{sub 2}O){sub n}H{sup +} (n = 0-21) and mixed protonated (or deprotonated) water-pyridine cluster ions: PyrH{sup +}(H{sub 2}O){sub n} (n = 0-15), Pyr{sub 2}H{sup +} (H{sub 2}O){sub n} (n = 0-9), and (Pyr-H){sup +} (H{sub 2}O).

  3. Intense Pulsed Heavy Ion Beam Technology

    Science.gov (United States)

    Masugata, Katsumi; Ito, Hiroaki

    Development of intense pulsed heavy ion beam accelerator technology is described for the application of materials processing. Gas puff plasma gun and vacuum arc discharge plasma gun were developed as an active ion source for magnetically insulated pulsed ion diode. Source plasma of nitrogen and aluminum were successfully produced with the gas puff plasma gun and the vacuum arc plasma gun, respectively. The ion diode was successfully operated with gas puff plasma gun at diode voltage 190 kV, diode current 2.2 kA and nitrogen ion beam of ion current density 27 A/cm2 was obtained. The ion composition was evaluated by a Thomson parabola spectrometer and the purity of the nitrogen ion beam was estimated to be 86%. The diode also operated with aluminum ion source of vacuum arc plasma gun. The ion diode was operated at 200 kV, 12 kA, and aluminum ion beam of current density 230 A/cm2 was obtained. The beam consists of aluminum ions (Al(1-3)+) of energy 60-400 keV, and protons (90-130 keV), and the purity was estimated to be 89 %. The development of the bipolar pulse accelerator (BPA) was reported. A double coaxial type bipolar pulse generator was developed as the power supply of the BPA. The generator was tested with dummy load of 7.5 ohm, bipolar pulses of -138 kV, 72 ns (1st pulse) and +130 kV, 70 ns (2nd pulse) were succesively generated. By applying the bipolar pulse to the drift tube of the BPA, nitrogen ion beam of 2 A/cm2 was observed in the cathode, which suggests the bipolar pulse acceleration.

  4. Intercostal high intensity focused ultrasound for liver ablation: The influence of beam shaping on sonication efficacy and near-field risks

    Energy Technology Data Exchange (ETDEWEB)

    Greef, M. de, E-mail: m.degreef@umcutrecht.nl; Wijlemans, J. W.; Bartels, L. W.; Moonen, C. T. W.; Ries, M. [Imaging Division, University Medical Center Utrecht, Utrecht 3508GA (Netherlands); Schubert, G.; Koskela, J. [Philips Healthcare, Vantaa FI-01511 (Finland)

    2015-08-15

    Purpose: One of the major issues in high intensity focused ultrasound ablation of abdominal lesions is obstruction of the ultrasound beam by the thoracic cage. Beam shaping strategies have been shown by several authors to increase focal point intensity while limiting rib exposure. However, as rib obstruction leaves only part of the aperture available for energy transmission, conserving total emitted acoustic power, the intensity in the near-field tissues inherently increases after beam shaping. Despite of effective rib sparing, those tissues are therefore subjected to increased risk of thermal damage. In this study, for a number of clinically representative intercostal sonication geometries, modeling clinically available hardware, the effect of beam shaping on both the exposure of the ribs and near-field to acoustic energy was evaluated and the implications for the volumetric ablation rate were addressed. Methods: A relationship between rib temperature rise and acoustic energy density was established by means of in vivo MR thermometry and simulations of the incident acoustic energy for the corresponding anatomies. This relationship was used for interpretation of rib exposure in subsequent numerical simulations in which rib spacing, focal point placement, and the focal point trajectory were varied. The time required to heat a targeted region to 65 °C was determined without and with the application of beam shaping. The required sonication time was used to calculate the acoustic energy density at the fat–muscle interface and at the surface of the ribs. At the fat–muscle interface, exposure was compared to available literature data and rib exposure was interpreted based on the earlier obtained relation between measured temperature rise and simulated acoustic energy density. To estimate the volumetric ablation rate, the cool-down time between periods of energy exposure was estimated using a time-averaged power limit of 100 kJ/h. Results: At the level of the ribs

  5. Gas Filled RF Resonator Hadron Beam Monitor for Intense Neutrino Beam Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yonehara, Katsuya [Fermilab; Abrams, Robert [MUONS Inc., Batavia; Dinkel, Holly [U. Missouri, Columbia; Freemire, Ben [IIT, Chicago; Johnson, Rolland [MUONS Inc., Batavia; Kazakevich, Grigory [MUONS Inc., Batavia; Tollestrup, Alvin [Fermilab; Zwaska, Robert [Fermilab

    2016-06-01

    MW-class beam facilities are being considered all over the world to produce an intense neutrino beam for fundamental particle physics experiments. A radiation-robust beam monitor system is required to diagnose the primary and secondary beam qualities in high-radiation environments. We have proposed a novel gas-filled RF-resonator hadron beam monitor in which charged particles passing through the resonator produce ionized plasma that changes the permittivity of the gas. The sensitivity of the monitor has been evaluated in numerical simulation. A signal manipulation algorithm has been designed. A prototype system will be constructed and tested by using a proton beam at the MuCool Test Area at Fermilab.

  6. High Intensity Beam Test of Low Z Materials for the Upgrade of SPS-to-LHC Transfer Line Collimators and LHC Injection Absorbers

    CERN Document Server

    Maciariello, Fausto; Butcher, Mark; Calviani, Marco; Folch, Ramon; Kain, Verena; Karagiannis, Konstantinos; Lamas Garcia, Inigo; Lechner, Anton; Nuiry, Francois-Xavier; Steele, Genevieve; Uythoven, Jan

    2016-01-01

    In the framework of the LHC Injector Upgrade (LIU) and High-Luminosity LHC (HL-LHC) project, the collimators in the SPS-to LHC transfer lines will undergo important modifications. The changes to these collimators will allow them to cope with beam brightness and intensity levels much increased with respect to their original design parameters: nominal and ultimate LHC. The necessity for replacement of the current materials will need to be confirmed by a test in the High Radiation to Materials (HRM) facility at CERN. This test will involve low Z materials (such as Graphite and 3-D Carbon/Carbon composite), and will recreate the worst case scenario those materials could see when directly impacted by High luminosity LHC (HL-LHC) or Batch Compression Merging and Splitting (BCMS) beams. Thermo-structural simulations used for the material studies and research, the experiment preparation phase, the experiment itself, pre irradiation analysis (including ultrasound and metrology tests on the target materials), the resul...

  7. High intensity protons in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Montag, C.; Ahrens, L.; Blaskiewicz, M.; Brennan, J. M.; Drees, K. A.; Fischer, W.; Huang, H.; Minty, M.; Robert-Demolaize, G.; Thieberger, P.; Yip, K.

    2012-01-05

    During the 2012 summer shutdown a pair of electron lenses will be installed in RHIC, allowing the beam-beam parameter to be increased by roughly 50 percent. To realize the corresponding luminosity increase bunch intensities have to be increased by 50 percent, to 2.5 {center_dot} 10{sup 11} protons per bunch. We list the various RHIC subsystems that are most affected by this increase, and propose beam studies to ensure their readiness. The proton luminosity in RHIC is presently limited by the beam-beam effect. To overcome this limitation, electron lenses will be installed in IR10. With the help of these devices, the headon beam-beam kick experienced during proton-proton collisions will be partially compensated, allowing for a larger beam-beam tuneshift at these collision points, and therefore increasing the luminosity. This will be accomplished by increasing the proton bunch intensity from the presently achieved 1.65 {center_dot} 10{sup 11} protons per bunch in 109 bunches per beam to 2.5 {center_dot} 10{sup 11}, thus roughly doubling the luminosity. In a further upgrade we aim for bunch intensities up to 3 {center_dot} 10{sup 11} protons per bunch. With RHIC originally being designed for a bunch intensity of 1 {center_dot} 10{sup 11} protons per bunch in 56 bunches, this six-fold increase in the total beam intensity by far exceeds the design parameters of the machine, and therefore potentially of its subsystems. In this note, we present a list of major subsystems that are of potential concern regarding this intensity upgrade, show their demonstrated performance at present intensities, and propose measures and beam experiments to study their readiness for the projected future intensities.

  8. Low-intensity beam diagnostics with particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Rovelli, A.; Ciavola, G.; Cuttone, G.; Finocchiaro, P.; Raia, G. [INFN-LNS, Via S. Sofia 44/A Catania, 95125 (Italy); De Martinis, C.; Giove, D. [INFN-LASA, Via F.lli Cervi 201 Segrate (Midway Islands), 20090 (Italy)

    1997-01-01

    The measure of low intensity beams at low-medium energy is one of the major challenge in beam diagnostics. This subject is of great interest for the design of accelerator-based medical and radioactive beam facilities. In this paper we discuss new developments in image-based devices to measure low-intensity beams. All the investigated devices must guarantee measurement of the total beam current and its transverse distribution. {copyright} {ital 1997 American Institute of Physics.}

  9. Laser-driven generation of ultra-intense proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Badziak, J.; Jablonski, S.; Kubkowska, M.; Parys, P.; Rosinski, M.; Wolowski, J. [EURATOM, Inst Plasma Phys and Laser Microfus, PL-00908 Warsaw (Poland); Antici, P.; Fuchs, J.; Mancic, A. [UPMC, LULI, Ecole Polytech, CNRS, CEA, F-91128 Palaiseau (France); Szydlowski, A. [Andrzej Soltan Inst Nucl Studies, Otwock (Poland)

    2010-07-01

    The results of experimental and numerical studies of high-intensity proton beam generation driven by a short laser pulse of relativistic intensity are reported. In the experiment, a 350 fs laser pulse of 1.06 or 0.53 m wavelength and intensity up to 2*10{sup 19} Wcm{sup -2} irradiated a thin (0.6-2{mu}m) plastic (PS) or Au/PS (plastic covered by 0.2{mu}m Au front layer) target along the target normal. The effect of laser intensity, the target structure and the laser wavelength on the proton beam parameters and laser-protons energy conversion efficiency were examined. Both the measurements and one-dimensional particle-in-cell simulations showed that MeV proton beams of intensity 10{sup 18}Wcm{sup -2} and current density 10{sup 12}Acm{sup -2} at the source can be produced when the laser intensity-wavelength squared product I{sub L{lambda}}{sup 2} is 10{sup 19}Wcm{sup -2}m{sup 2} and the laser-target interaction conditions approach the skin-layer ponderomotive acceleration (SLPA) requirements. The simulations also proved that at I{sub L{lambda}}{sup 2} {>=} 5*10{sup 19}Wcm{sup -2}m{sup 2} and {lambda} {<=} 0.53{mu}m, SLPA clearly prevails over other acceleration mechanisms and it can produce multi-MeV proton beams of extremely high intensities above 10{sup 20}Wcm{sup -2}. (authors)

  10. Low intensity MTE beam in the SPS

    CERN Document Server

    Bohl, T

    2009-01-01

    In view of extracting fixed target type of beams for SPS fixed target physics or CNGS operation with the Multi-Turn-Extraction (MTE) scheme,an h = 16 MTE beam was produced in the CPS. The transmission and the longitudinal beam structure of this beam is compared with the beam extracted by CT.

  11. Stability and Halo Formation in Axisymmetric Intense Beams

    CERN Document Server

    Gluckstern, R L; Gluckstern, Robert L.; Kurennoy, Sergey S.

    1998-01-01

    Beam stability and halo formation in high-intensity axisymmetric 2D beams in a uniform focusing channel are analyzed using particle-in-cell simulations. The tune depression - mismatch space is explored for the uniform (KV) distribution of the particle transverse-phase-space density, as well as for more realistic ones (in particular, the water-bag distribution), to determine the stability limits and halo parameters. The numerical results show an agreement with predictions of the analytical model for halo formation (R.L. Gluckstern, Phys. Rev. Letters, 73 (1994) 1247).

  12. Stability and Halo Formation in Axisymmetric Intense Beams.

    Science.gov (United States)

    Gluckstern, Robert L.; Kurennoy, Sergey S.

    1997-05-01

    Beam stability and halo formation in high-intensity axisymmetric 2D beams in a uniform focusing channel are analyzed using particle-in-cell simulations. The tune depression - mismatch space is explored for the uniform distribution of the particle transverse phase space density (Kapchinsky-Vladimirsky), as well as for more realistic ones (in particular, the water-bag distribution), to determine the stability limits and halo parameters. The numerical results obtained are compared and show an agreement with the predictions of the analytical model for halo formation developed earlier (R.L. Gluckstern, Phys. Rev. Lett., 73), 1247 (1994)..

  13. Stability and halo formation in axisymmetric intense beams

    Energy Technology Data Exchange (ETDEWEB)

    Gluckstern, R.L. [Univ. of Maryland, College Park, MD (United States); Kurennoy, S.S. [Los Alamos National Lab., NM (United States)

    1997-10-01

    Beam stability and halo formation in high-intensity axisymmetric 2D beams in a uniform focusing channel are analyzed using particle-in-cell simulations. The tune depression-mismatch space is explored for the uniform (KV) distribution of the particle transverse-phase-space density, as well as for more realistic ones (in particular, the water-bag distribution), to determine the stability limits and halo parameters. The numerical results show an agreement with predictions of the analytical model for halo formation.

  14. Intense Ion Beam for Warm Dense Matter Physics

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, Joshua Eugene [Univ. of California, Berkeley, CA (United States)

    2008-01-01

    The Neutralized Drift Compression Experiment (NDCX) at Lawrence Berkeley National Laboratory is exploring the physical limits of compression and focusing of ion beams for heating material to warm dense matter (WDM) and fusion ignition conditions. The NDCX is a beam transport experiment with several components at a scale comparable to an inertial fusion energy driver. The NDCX is an accelerator which consists of a low-emittance ion source, high-current injector, solenoid matching section, induction bunching module, beam neutralization section, and final focusing system. The principal objectives of the experiment are to control the beam envelope, demonstrate effective neutralization of the beam space-charge, control the velocity tilt on the beam, and understand defocusing effects, field imperfections, and limitations on peak intensity such as emittance and aberrations. Target heating experiments with space-charge dominated ion beams require simultaneous longitudinal bunching and transverse focusing. A four-solenoid lattice is used to tune the beam envelope to the necessary focusing conditions before entering the induction bunching module. The induction bunching module provides a head-to-tail velocity ramp necessary to achieve peak axial compression at the desired focal plane. Downstream of the induction gap a plasma column neutralizes the beam space charge so only emittance limits the focused beam intensity. We present results of beam transport through a solenoid matching section and simultaneous focusing of a singly charged K+ ion bunch at an ion energy of 0.3 MeV. The results include a qualitative comparison of experimental and calculated results after the solenoid matching section, which include time resolved current density, transverse distributions, and phase-space of the beam at different diagnostic planes. Electron cloud and gas measurements in the solenoid lattice and in the vicinity of intercepting diagnostics are also presented. Finally

  15. Production of medical radioisotopes with high specific activity in photonuclear reactions with γ-beams of high intensity and large brilliance

    Science.gov (United States)

    Habs, D.; Köster, U.

    2011-05-01

    We study the production of radioisotopes for nuclear medicine in ( γ, xn+ yp) photonuclear reactions or ( γ, γ') photoexcitation reactions with high-flux [(1013-1015) γ/s], small diameter ˜(100 μm)2 and small bandwidth (Δ E/ E≈10-3-10-4) γ beams produced by Compton back-scattering of laser light from relativistic brilliant electron beams. We compare them to (ion, xn+ yp) reactions with (ion = p,d, α) from particle accelerators like cyclotrons and (n, γ) or (n,f) reactions from nuclear reactors. For photonuclear reactions with a narrow γ-beam the energy deposition in the target can be managed by using a stack of thin target foils or wires, hence avoiding direct stopping of the Compton and pair electrons (positrons). However, for ions with a strong atomic stopping only a fraction of less than 10-2 leads to nuclear reactions resulting in a target heating, which is at least 105 times larger per produced radioactive ion and often limits the achievable activity. In photonuclear reactions the well defined initial excitation energy of the compound nucleus leads to a small number of reaction channels and enables new combinations of target isotope and final radioisotope. The narrow bandwidth γ excitation may make use of the fine structure of the Pygmy Dipole Resonance (PDR) or fluctuations in γ-width leading to increased cross sections. Within a rather short period compared to the isotopic half-life, a target area of the order of (100 μm)2 can be highly transmuted, resulting in a very high specific activity. ( γ, γ') isomer production via specially selected γ cascades allows to produce high specific activity in multiple excitations, where no back-pumping of the isomer to the ground state occurs. We discuss in detail many specific radioisotopes for diagnostics and therapy applications. Photonuclear reactions with γ-beams allow to produce certain radioisotopes, e.g. 47Sc, 44Ti, 67Cu, 103Pd, 117 m Sn, 169Er, 195 m Pt or 225Ac, with higher specific activity

  16. High Intensity High Charge State ECR Ion Sources

    CERN Document Server

    Leitner, Daniela

    2005-01-01

    The next-generation heavy ion beam accelerators such as the proposed Rare Isotope Accelerator (RIA), the Radioactive Ion Beam Factory at RIKEN, the GSI upgrade project, the LHC-upgrade, and IMP in Lanzhou require a great variety of high charge state ion beams with a magnitude higher beam intensity than currently achievable. High performance Electron Cyclotron Resonance (ECR) ion sources can provide the flexibility since they can routinely produce beams from hydrogen to uranium. Over the last three decades, ECR ion sources have continued improving the available ion beam intensities by increasing the magnetic fields and ECR heating frequencies to enhance the confinement and the plasma density. With advances in superconducting magnet technology, a new generation of high field superconducting sources is now emerging, designed to meet the requirements of these next generation accelerator projects. The talk will briefly review the field of high performance ECR ion sources and the latest developments for high intens...

  17. LHC Report: 25 ns spacing yields record beam intensity

    CERN Multimedia

    The LHC team

    2012-01-01

    Over the weekend the LHC broke two records: a record number of 2,748 proton bunches were injected into the accelerator giving a record beam intensity of around 2.7 x 1014 protons in both beams. These beams have yet to face the challenge of "ramping" to high energy.   These very good results were made possible by a new beam configuration: the design value of 25 nanosecond spacing between proton bunches replaced - for the first time – the typical 50 nanosecond spacing. This test run was done at 450 GeV with no collisions. Up to now, the LHC has been running with around 1,380 bunches with 50 nanoseconds between bunches. By going to 25 nanoseconds, the LHC operations team can double the number of bunches to around 2,800. One of the main limitations for this mode of operation is the so-called electron cloud (see Bulletin 15-16/2011) that is strongly enhanced by the reduced spacing among bunches.  The electron cloud has nasty effects on the beam (beam size increase...

  18. Analytical Solutions for the Nonlinear Longitudinal Drift Compression (Expansion) of Intense Charged Particle Beams

    Energy Technology Data Exchange (ETDEWEB)

    Edward A. Startsev; Ronald C. Davidson

    2004-04-09

    To achieve high focal spot intensities in heavy ion fusion, the ion beam must be compressed longitudinally by factors of ten to one hundred before it is focused onto the target. The longitudinal compression is achieved by imposing an initial velocity profile tilt on the drifting beam. In this paper, the problem of longitudinal drift compression of intense charged particle beams is solved analytically for the two important cases corresponding to a cold beam, and a pressure-dominated beam, using a one-dimensional warm-fluid model describing the longitudinal beam dynamics.

  19. Phase contrast imaging using Betatron x-ray beams produced by a 100 TW high intensity laser system

    Science.gov (United States)

    Fourmaux, Sylvain; Corde, Sebastien; Ta Phuoc, Kim; Lassonde, Philippe; Martin, Francois; Malka, Victor; Rousse, Antoine; Kieffer, Jean

    2011-10-01

    Development of x-ray phase contrast imaging applications with a laboratory scale source have been limited by the long exposure time needed to obtain one image. We demonstrate, using the Betatron x-ray radiation produced when electrons are accelerated and wiggled in the laser-wakefield cavity, the potential of Betatron x-ray radiation for femtosecond phase contrast imaging. We characterize the x-ray source using a knife edge technique and nylon wires for calibration. We then show that high-quality phase contrast images of complex objects located in air, can be obtained with only a single laser shot. The Betatron x-ray source used in this demonstration experiment has a source diameter of 1.7 microns and produces a synchrotron spectrum with critical energy Ec = 12 . 3 + / - 2 . 5 keV and 109 photons per shot in the whole spectrum.

  20. Atomic Oxygen (ATOX) simulation of Teflon FEP and Kapton H surfaces using a high intensity, low energy, mass selected, ion beam facility

    Science.gov (United States)

    Vered, R.; Grossman, E.; Lempert, G. D.; Lifshitz, Y.

    1994-01-01

    A high intensity (greater than 10(exp 15) ions/sq cm) low energy (down to 5 eV) mass selected ion beam (MSIB) facility was used to study the effects of ATOX on two polymers commonly used for space applications (Kapton H and Teflon FEP). The polymers were exposed to O(+) and Ne(+) fluences on 10(exp 15) - 10(exp 19) ions/sq cm, using 30eV ions. A variety of analytical methods were used to analyze the eroded surfaces including: (1) atomic force microscopy (AFM) for morphology measurements; (2) total mass loss measurements using a microbalance; (3) surface chemical composition using x-ray photoelectron spectroscopy (XPS), and (4) residual gas analysis (RGA) of the released gases during bombardment. The relative significance of the collisional and chemical degradation processes was evaluated by comparing the effects of Ne(+) and O(+) bombardment. For 30 eV ions it was found that the Kapton is eroded via chemical mechanisms while Teflon FEP is eroded via collisional mechanisms. AFM analysis was found very powerful in revealing the evolution of the damage from its initial atomic scale (roughness of approx. 1 nm) to its final microscopic scale (roughness greater than 1 micron). Both the surface morphology and the average roughness of the bombarded surfaces (averaged over 1 micron x 1 micron images by the system's computer) were determined for each sample. For 30 eV a non linear increase of the Kapton roughness with the O(+) fluence was discovered (a slow increase rate for fluences phi less than 5 x 10(exp 17) O(+)/sq cm, and a rapid increase rate for phi greater than 5 x 10(exp 17) O(+)/sq cm). Comparative studies on the same materials exposed to RF and DC oxygen plasmas indicate that the specific details of the erosion depend on the simulation facility emphasizing the advantages of the ion beam facility.

  1. The feasibility and safety of high-intensity focused ultrasound combined with low-dose external beam radiotherapy as supplemental therapy for advanced prostate cancer following hormonal therapy

    Institute of Scientific and Technical Information of China (English)

    Rui-Yi Wu; Guo-Min Wang; Lei Xu; Bo-Heng Zhang; Ye-Qing Xu; Zhao-Chong Zeng; Bing Chen

    2011-01-01

    The aim of this study was to investigate the feasibility and safety of high-intensity focused ultrasound (HIFU) combined with (+) low-dose external beam radiotherapy (LRT) as supplemental therapy for advanced prostate cancer (PCa) following hormonal therapy (HT). Our definition of HIFU+LRT refers to treating primary tumour lesions with HIFU in place of reduced field boost irradiation to the prostate, while retaining four-field box irradiation to the pelvis in conventional-dose external beam radiotherapy (CRT). We performed a prospective, controlled and non-randomized study on 120 patients with advanced PCa after HT who received HIFU, CRT, HIFU+LRT and HT alone, respectively. CT/MR imaging showed the primary tumours and pelvic lymph node metastases visibly shrank or even disappeared after HIFU+LRT treatment. There were significant differences among four groups with regard to overall survival (OS) and disease-specific survival (DSS) curves (P=0.018 and 0.015). Further comparison between each pair of groups suggested that the long-term DSS of the HIFU+LRT group was higher than those of the other three groups, but there was no significant difference between the HIFU+LRT group and the CRT group. Multivariable Cox's proportional hazard model showed that both HIFU+LRT and CRT were independently associated with DSS (P=0.001 and 0.035) and had protective effects with regard to the risk of death. Compared with CRT, HIFU+LRT significantly decreased incidences of radiation-related late gastrointestinal (GI) and genitourinary (GU) toxicity grade ≥II. In conclusion, long-term survival of patients with advanced PCa benefited from strengthening local control of primary tumour and regional lymph node metastases after HT. As an alternative to CRT, HIFU+LRT showed good efficacy and better safety.

  2. Delivering the world’s most intense muon beam

    Directory of Open Access Journals (Sweden)

    S. Cook

    2017-03-01

    Full Text Available A new muon beam line, the muon science innovative channel, was set up at the Research Center for Nuclear Physics, Osaka University, in Osaka, Japan, using the 392 MeV proton beam impinging on a target. The production of an intense muon beam relies on the efficient capture of pions, which subsequently decay to muons, using a novel superconducting solenoid magnet system. After the pion-capture solenoid, the first 36° of the curved muon transport line was commissioned and the muon flux was measured. In order to detect muons, a target of either copper or magnesium was placed to stop muons at the end of the muon beam line. Two stations of plastic scintillators located upstream and downstream from the muon target were used to reconstruct the decay spectrum of muons. In a complementary method to detect negatively charged muons, the x-ray spectrum yielded by muonic atoms in the target was measured in a germanium detector. Measurements, at a proton beam current of 6 pA, yielded (10.4±2.7×10^{5}  muons per watt of proton beam power (μ^{+} and μ^{-}, far in excess of other facilities. At full beam power (400 W, this implies a rate of muons of (4.2±1.1×10^{8}  muons s^{−1}, among the highest in the world. The number of μ^{-} measured was about a factor of 10 lower, again by far the most efficient muon beam produced. The setup is a prototype for future experiments requiring a high-intensity muon beam, such as a muon collider or neutrino factory, or the search for rare muon decays which would be a signature for phenomena beyond the Standard Model of particle physics. Such a muon beam can also be used in other branches of physics, nuclear and condensed matter, as well as other areas of scientific research.

  3. Determining temperature distribution in tissue in the focal plane of the high (>100 W/cm(2)) intensity focused ultrasound beam using phase shift of ultrasound echoes.

    Science.gov (United States)

    Karwat, Piotr; Kujawska, Tamara; Lewin, Peter A; Secomski, Wojciech; Gambin, Barbara; Litniewski, Jerzy

    2016-02-01

    In therapeutic applications of High Intensity Focused Ultrasound (HIFU) the guidance of the HIFU beam and especially its focal plane is of crucial importance. This guidance is needed to appropriately target the focal plane and hence the whole focal volume inside the tumor tissue prior to thermo-ablative treatment and beginning of tissue necrosis. This is currently done using Magnetic Resonance Imaging that is relatively expensive. In this study an ultrasound method, which calculates the variations of speed of sound in the locally heated tissue volume by analyzing the phase shifts of echo-signals received by an ultrasound scanner from this very volume is presented. To improve spatial resolution of B-mode imaging and minimize the uncertainty of temperature estimation the acoustic signals were transmitted and received by 8 MHz linear phased array employing Synthetic Transmit Aperture (STA) technique. Initially, the validity of the algorithm developed was verified experimentally in a tissue-mimicking phantom heated from 20.6 to 48.6 °C. Subsequently, the method was tested using a pork loin sample heated locally by a 2 MHz pulsed HIFU beam with focal intensity ISATA of 129 W/cm(2). The temperature calibration of 2D maps of changes in the sound velocity induced by heating was performed by comparison of the algorithm-determined changes in the sound velocity with the temperatures measured by thermocouples located in the heated tissue volume. The method developed enabled ultrasound temperature imaging of the heated tissue volume from the very inception of heating with the contrast-to-noise ratio of 3.5-12 dB in the temperature range 21-56 °C. Concurrently performed, conventional B-mode imaging revealed CNR close to zero dB until the temperature reached 50 °C causing necrosis. The data presented suggest that the proposed method could offer an alternative to MRI-guided temperature imaging for prediction of the location and extent of the thermal lesion prior to applying the

  4. Influence of the intensity gradient upon HHG from free electrons scattered by an intense laser beam

    CERN Document Server

    Li, Ankang; Ren, Na; Wang, Pingxiao; Zhu, Wenjun; Li, Xiaoya; Hoehn, Ross; Kais, Sabre

    2013-01-01

    When an electron is scattered by a tightly-focused laser beam in vacuum, the intensity gradient is a critical factor to influence the electron dynamics, for example, the electron energy exchange with the laser fields as have been explored before [P.X.Wang et al.,J. Appl. Phys. 91, 856 (2002]. In this paper, we have further investigated its influence upon the electron high-harmonic generation (HHG) by treating the spacial gradient of the laser intensity as a ponderomotive potential. Based upon perturbative QED calculations, it has been found that the main effect of the intensity gradient is the broadening of the originally line HHG spectra. A one-to-one relationship can be built between the beam width and the corresponding line width. Hence this finding may provides us a promising way to measure the beam width of intense lasers in experiments. In addition, for a laser pulse, we have also studied the different influences from transverse and longitudinal intensity gradients upon HHG.

  5. Horizontal dilution refrigerator for use in intense proton beams

    CERN Document Server

    Bywater, J A; Crabb, D G

    1982-01-01

    A fast loading high-power horizontal dilution refrigerator insert has been built for use in the Michigan polarized proton target (PPT V). This PPT will be used in measurements of spin effects in high P/sub perpendicular to / elastic p-p scattering at the Brookhaven AGS. The cooling power is compared with the existing interchangeable /sup 3/He evaporation insert, and with similar dilution refrigerators at CERN and Bonn. The relative merits of these two types of refrigerators in absorbing the heat loads of high intensity beams is discussed.

  6. Splitting of high power, cw proton beams

    CERN Document Server

    Facco, Alberto; Berkovits, Dan; Yamane, Isao

    2007-01-01

    A simple method for splitting a high power, continuous wave (cw) proton beam in two or more branches with low losses has been developed in the framework of the EURISOL (European Isotope Separation On-Line adioactive Ion Beam Facility) design study. The aim of the system is to deliver up to 4 MW of H beam to the main radioactive ion beam production target, and up to 100 kWof proton beams to three more targets, simultaneously. A three-step method is used, which includes magnetic neutralization of a fractionof the main H- beam, magnetic splitting of H- and H0, and stripping of H0 to H+. The method allowsslow raising and individual fine adjustment of the beam intensity in each branch.

  7. Intense beams at the micron level for the Next Linear Collider

    Energy Technology Data Exchange (ETDEWEB)

    Seeman, J.T.

    1991-08-01

    High brightness beams with sub-micron dimensions are needed to produce a high luminosity for electron-positron collisions in the Next Linear Collider (NLC). To generate these small beam sizes, a large number of issues dealing with intense beams have to be resolved. Over the past few years many have been successfully addressed but most need experimental verification. Some of these issues are beam dynamics, emittance control, instrumentation, collimation, and beam-beam interactions. Recently, the Stanford Linear Collider (SLC) has proven the viability of linear collider technology and is an excellent test facility for future linear collider studies.

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

    Science.gov (United States)

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

    2011-10-01

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

  9. R & D of a Gas-Filled RF Beam Profile Monitor for Intense Neutrino Beam Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yonehara, K. [Fermilab; Backfish, M. [Fermilab; Moretti, A. [Fermilab; Tollestrup, A. V. [Fermilab; Watts, A. [Fermilab; Zwaska, R. M. [Fermilab; Abrams, R. [MUONS Inc., Batavia; Cummings, M. A.; Dudas, A. [MUONS Inc., Batavia; Johnson, R. P. [MUONS Inc., Batavia; Kazakevich, G. [MUONS Inc., Batavia; Neubauer, M. [MUONS Inc., Batavia; Liu, Q. [Case Western Reserve U.

    2017-05-01

    We report the R&D of a novel radiation-robust hadron beam profile monitor based on a gas-filled RF cavity for intense neutrino beam experiments. An equivalent RF circuit model was made and simulated to optimize the RF parameter in a wide beam intensity range. As a result, the maximum acceptable beam intensity in the monitor is significantly increased by using a low-quality factor RF cavity. The plan for the demonstration test is set up to prepare for future neutrino beam experiments.

  10. Study on High Intensity High Charge State Lead Ion Beam Production and Optimize%强流高电荷态Pb离子束的产生与优化研究

    Institute of Scientific and Technical Information of China (English)

    何伟; 李锦钰; 赵环昱; 曹云; 孙良亭; 赵红卫; 张子民

    2005-01-01

    随着原子物理及表面物理研究的发展,高电荷态金属离子束的需求日益增多.近来,在中国科学院近代物理研究所14.5GHz LECR3离子源实验平台上,以炉子法产生的铅离子束作为研究对象,进行了一系列ECR离子源关键参数(如:磁场、炉子功率、掺气等)影响高电荷态铅离子束产额的实验研究,在此基础上,调整优化了LECR3离子源的状态参数,从而获得了强流高电荷态铅离子束18etA 207pb30+和6.7eμA207pb37+.%High charge state metal ion beam is quite effective and essential for new investigations on atomic physics and surface physics. Recently, The high intensity high charge state lead ion beams have been produced with IMP 14.5GHz LECR3, we investigated experimentally influences of some key parameters,such as magnetic field, electrical power on oven, gas mixing etc., on lead ion beam production. Through optimization of the ion source conditions, stable 207Pb30+ beam of 18eμA and 207Pb37+ beam of 6.7eμA have been obtained with oven method at 20kV extraction voltage.

  11. Research on Brightness Measurement of Intense Electron Beam

    CERN Document Server

    Wang, Yuan; Zhang, Huang; Yang, GuoJun; Li, YiDing; Li, Jin

    2015-01-01

    The mostly research fasten on high emission density of injector to study electron beam's brightness in LIA. Using the injector(2MeV) was built to research brightness of multi-pulsed high current(KA) electron beam, and researchs three measurement method (the pepper-pot method, beam collimator without magnetic field, beam collimator with magnetic field method) to detect beam's brightness with time-resolved measurement system.

  12. Cryogenic semiconductor high-intensity radiation monitors

    CERN Document Server

    Palmieri, V G; Borer, K; Casagrande, L; Da Vià, C; Devine, S R H; Dezillie, B; Esposito, A; Granata, V; Hauler, F; Jungermann, L; Li, Z; Lourenço, C; Niinikoski, T O; O'Shea, V

    2003-01-01

    This paper describes a novel technique to monitor high-intensity particle beams by means of a semiconductor detector. It consists of cooling a semiconductor detector down to cryogenic temperature to suppress the thermally generated leakage current and to precisely measure the integrated ionization signal. It will be shown that such a device provides very good linearity and a dynamic range wider than is possible with existing techniques. Moreover, thanks to the Lazarus effect, extreme radiation hardness can be achieved providing in turn absolute intensity measurements against precise calibration of the device at low beam flux.

  13. Study of positronium in low-k dielectric films by means of 2D-angular correlation experiments at a high-intensity slow-positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Gessmann, T.; Petkov, M.P.; Weber, M.H.; Lynn, K.G. [Washington State Univ., Pullman, WA (United States). Dept. of Physics; Rodbell, K.P. [IBM Watson Research Center, Yorktown Heights, NY (United States); Asoka-Kumar, P.; Stoeffl, W.; Howell, R.H. [Lawrence Livermore National Lab., CA (United States). Physics Dept.

    2001-07-01

    Depth-resolved measurements of two-dimensional angular correlation of annihilation radiation (2D-ACAR) were performed at the intense slow-positron beam at Lawrence Livermore National Laboratory. The formation of positronium was studied in thin films of methylsilsesquioxane (MSSQ) spin-on glass containing large open-volume defects (voids). Two samples with different average void sizes were investigated and positronium formation could be found in both cases. The width of the angular correlation related to annihilation of para-positronium (p-Ps) increased with the void size consistent with the annihilation of nonthermalized p-Ps. (orig.)

  14. Semi-classical beam cooling in an intense laser pulse

    CERN Document Server

    Yoffe, Samuel R; Noble, Adam; Jaroszynski, Dino A

    2014-01-01

    We present a novel technique for studying the evolution of a particle distribution using single particle dynamics such that the distribution can be accurately reconstructed using fewer particles than existing approaches. To demonstrate this, the Landau-Lifshiftz description of radiation reaction is adapted into a semi-classical model, for which the Vlasov equation is intractable. Collision between an energetic electron bunch and high-intensity laser pulses are then compared using the two theories. Reduction in beam cooling is observed for the semi-classical case.

  15. Progress of General Test Stand for Intensive Beam Cyclotron

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>The general test stand for intensive beam cyclotron is one of the preliminary tasks of BRIF project at CIAE. The test stand, which actually is a small compact cyclotron with designed energy of 10 MeV,

  16. Drift compression of an intense neutralized ion beam

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-10-25

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

  17. Aperture Effects and Mismatch Oscillations in an Intense Electron Beam

    Energy Technology Data Exchange (ETDEWEB)

    Harris, J R; O' Shea, P G

    2008-05-12

    When an electron beam is apertured, the transmitted beam current is the product of the incident beam current density and the aperture area. Space charge forces generally cause an increase in incident beam current to result in an increase in incident beam spot size. Under certain circumstances, the spot size will increase faster than the current, resulting in a decrease in current extracted from the aperture. When using a gridded electron gun, this can give rise to negative transconductance. In this paper, we explore this effect in the case of an intense beam propagating in a uniform focusing channel. We show that proper placement of the aperture can decouple the current extracted from the aperture from fluctuations in the source current, and that apertures can serve to alter longitudinal space charge wave propagation by changing the relative contribution of velocity and current modulation present in the beam.

  18. Faraday Cup - it is used to measure beam intensities at low energy beams.

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    A Faraday Cup is used to measure beam intensities at low energy beams. An electrically isolated metallic electrode intercepts the beam and captures all its charges. These charges are integrated using an current sensitive amplifier. When the beam impinges onto the electrode surface low energy electrons are liberated. In order to prevent these electrons from escaping the cup and thus falsifying the measurement, a repeller electrode with negative potential pushes the electrons back onto the electrode.

  19. Concept for a new high resolution high intensity diffractometer

    Energy Technology Data Exchange (ETDEWEB)

    Stuhr, U. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    A concept of a new time-of-flight powder-diffractometer for a thermal neutral beam tube at SINQ is presented. The design of the instrument optimises the contradictory conditions of high intensity and high resolution. The high intensity is achieved by using many neutron pulses simultaneously. By analysing the time-angle-pattern of the detected neutrons an assignment of the neutrons to a single pulse is possible. (author) 3 figs., tab., refs.

  20. New techniques in hadrontherapy: intensity modulated proton beams.

    Science.gov (United States)

    Cella, L; Lomax, A; Miralbell, R

    2001-01-01

    Inverse planning and intensity modulated (IM) X-ray beam treatment techniques can achieve significant improvements in dose distributions comparable to those obtained with forward planned proton beams. However, intensity modulation can also be applied to proton beams and further optimization in dose distribution can reasonably be expected. A comparative planning exercise between IM X-rays and IM proton beams was carried out on two different tumor cases: a pediatric rhabdomyosarcoma and a prostate cancer. Both IM X-rays and IM protons achieved equally homogenous coverage of the target volume in the two tumor sites. Predicted NTCPs were equally low for both treatment techniques. Nevertheless, a reduced low-to-medium dose to the organs at risk and a lesser integral non-target mean dose for IM protons in the two cases favored the use of IM proton beams.

  1. The high intensity neutron source FRANZ

    CERN Document Server

    Lederer, Claudia

    2014-01-01

    The Frankfurt neutron source of Stern Gerlach Zentrum FRANZ is currently under construction at the University of Frankfurt. At FRANZ, a high intensity neutron beam in the keV energy region will be produced by bombarding a $^7$Li target with a proton beam of several mA. These unprecedented high neutron fluxes will allow a number of neutron induced cross section measurements for the first time. Measurements can be performed by the time-of-flight and by the activation technique.

  2. Stopping intense beams of internally cold molecules via centrifugal forces

    Science.gov (United States)

    Wu, Xing; Gantner, Thomas; Zeppenfeld, Martin; Chervenkov, Sotir; Rempe, Gerhard

    2016-05-01

    Cryogenic buffer-gas cooling produces intense beams of internally cold molecules. It offers a versatile source for studying collision dynamics and reaction pathways in the cold regime, and could open new avenues for controlled chemistry, precision spectroscopy, and exploration of fundamental physics. However, an efficient deceleration of these beams still presents a challenge. Here, we demonstrate that intense and continuous beams of electrically guided molecules produced by a cryogenic buffer-gas cell can be brought to a halt by the centrifugal force in a rotating frame. Various molecules (e.g. CH3F and CF3CCH) are decelerated to below 20m /s at a corresponding output intensity of ~ 6 ×109mm-2 .s-1 . In addition, our RF-resonant depletion detection shows that up to 90 % rotational-state purity can be achieved in the so-produced slow molecular beams.

  3. Electron Production and Collective Field Generation in Intense Particle Beams

    Energy Technology Data Exchange (ETDEWEB)

    Molvik, A W; Vay, J; Cohen, R; Friedman, A; Lee, E; Verboncoeur, J; Covo, M K

    2006-02-09

    Electron cloud effects (ECEs) are increasingly recognized as important, but incompletely understood, dynamical phenomena, which can severely limit the performance of present electron colliders, the next generation of high-intensity rings, such as PEP-II upgrade, LHC, and the SNS, the SIS 100/200, or future high-intensity heavy ion accelerators such as envisioned in Heavy Ion Inertial Fusion (HIF). Deleterious effects include ion-electron instabilities, emittance growth, particle loss, increase in vacuum pressure, added heat load at the vacuum chamber walls, and interference with certain beam diagnostics. Extrapolation of present experience to significantly higher beam intensities is uncertain given the present level of understanding. With coordinated LDRD projects at LLNL and LBNL, we undertook a comprehensive R&D program including experiments, theory and simulations to better understand the phenomena, establish the essential parameters, and develop mitigating mechanisms. This LDRD project laid the essential groundwork for such a program. We developed insights into the essential processes, modeled the relevant physics, and implemented these models in computational production tools that can be used for self-consistent study of the effect on ion beams. We validated the models and tools through comparison with experimental data, including data from new diagnostics that we developed as part of this work and validated on the High-Current Experiment (HCX) at LBNL. We applied these models to High-Energy Physics (HEP) and other advanced accelerators. This project was highly successful, as evidenced by the two paragraphs above, and six paragraphs following that are taken from our 2003 proposal with minor editing that mostly consisted of changing the tense. Further benchmarks of outstanding performance are: we had 13 publications with 8 of them in refereed journals, our work was recognized by the accelerator and plasma physics communities by 8 invited papers and we have 5

  4. Mixing intensity modulated electron and photon beams: combining a steep dose fall-off at depth with sharp and depth-independent penumbras and flat beam profiles.

    Science.gov (United States)

    Korevaar, E W; Heijmen, B J; Woudstra, E; Huizenga, H; Brahme, A

    1999-09-01

    For application in radiotherapy, intensity modulated high-energy electron and photon beams were mixed to create dose distributions that feature: (a) a steep dose fall-off at larger depths, similar to pure electron beams, (b) flat beam profiles and sharp and depth-independent beam penumbras, as in photon beams, and (c) a selectable skin dose that is lower than for pure electron beams. To determine the required electron and photon beam fluence profiles, an inverse treatment planning algorithm was used. Mixed beams were realized at a MM50 racetrack microtron (Scanditronix Medical AB, Sweden), and evaluated by the dose distributions measured in a water phantom. The multileaf collimator of the MM50 was used in a static mode to shape overlapping electron beam segments, and the dynamic multileaf collimation mode was used to realize the intensity modulated photon beam profiles. Examples of mixed beams were generated at electron energies of up to 40 MeV. The intensity modulated electron beam component consists of two overlapping concentric fields with optimized field sizes, yielding broad, fairly depth-independent overall beam penumbras. The matched intensity modulated photon beam component has high fluence peaks at the field edges to sharpen this penumbra. The combination of the electron and the photon beams yields dose distributions with the characteristics (a)-(c) mentioned above.

  5. Mean intensity of vortex Bessel beams propagating in turbulent atmosphere.

    Science.gov (United States)

    Lukin, Igor P

    2014-05-20

    Transformation of vortex Bessel beams during propagation in turbulent atmosphere is theoretically analyzed. Deforming influence of the random inhomogeneity of the turbulent medium on propagation of diffraction-free beams leads to disappearance of their invariant properties. In the given research, features of evolution of the spatial structure of distribution of mean intensity of vortex Bessel beams in turbulent atmosphere are analyzed. A quantitative criterion of possibility of carrying over of a dark central domain by vortex Bessel beams in a turbulent atmosphere is derived. The analysis of the behavior of several physical parameters of mean-level optical radiation shows that the shape stability of a vortex Bessel beam increases with the topological charge of this beam during its propagation in a turbulent atmosphere.

  6. High-power radio frequency pulse generation and extration based on wakefield excited by an intense charged particle beam in dielectric-loaded waveguides.

    Energy Technology Data Exchange (ETDEWEB)

    Gao, F.; High Energy Physics; Illinois Inst. of Tech

    2009-07-24

    Power extraction using a dielectric-loaded (DL) waveguide is a way to generate high-power radio frequency (RF) waves for future particle accelerators, especially for two-beam-acceleration. In a two-beam-acceleration scheme, a low-energy, high-current particle beam is passed through a deceleration section of waveguide (decelerator), where the power from the beam is partially transferred to trailing electromagnetic waves (wakefields); then with a properly designed RF output coupler, the power generated in the decelerator is extracted to an output waveguide, where finally the power can be transmitted and used to accelerate another usually high-energy low-current beam. The decelerator, together with the RF output coupler, is called a power extractor. At Argonne Wakefield Accelerator (AWA), we designed a 7.8GHz power extractor with a circular DL waveguide and tested it with single electron bunches and bunch trains. The output RF frequency (7.8GHz) is the sixth harmonic of the operational frequency (1.3GHz) of the electron gun and the linac at AWA. In single bunch excitation, a 1.7ns RF pulse with 30MW of power was generated by a single 66nC electron bunch passing through the decelerator. In subsequent experiments, by employing different splitting-recombining optics for the photoinjector laser, electron bunch trains were generated and thus longer RF pulses could be successfully generated and extracted. In 16-bunch experiments, 10ns and 22ns RF pulses have been generated and extracted; and in 4-bunch experiments, the maximum power generated was 44MW with 40MW extracted. A 26GHz DL power extractor has also been designed to test this technique in the millimeter-wave range. A power level of 148MW is expected to be generated by a bunch train with a bunch spacing of 769ps and bunch charges of 20nC each. The arrangement for the experiment is illustrated in a diagram. Higher-order-mode (HOM) power extraction has also been explored in a dual-frequency design. By using a bunch

  7. Proton Beam Intensity Upgrades for the Neutrino Program at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, C. M. [Fermilab

    2016-12-15

    Fermilab is committed to upgrading its accelerator complex towards the intensity frontier to pursue HEP research in the neutrino sector and beyond. The upgrade has two steps: 1) the Proton Improvement Plan (PIP), which is underway, has its primary goal to start providing 700 kW beam power on NOvA target by the end of 2017 and 2) the foreseen PIP–II will replace the existing LINAC, a 400 MeV injector to the Booster, by an 800 MeV superconducting LINAC by the middle of next decade, with output beam intensity from the Booster increased significantly and the beam power on the NOvA target increased to <1.2 MW. In any case, the Fermilab Booster is going to play a very significant role for the next two decades. In this context, we have recently developed and commissioned an innovative beam injection scheme for the Booster called "early injection scheme". This scheme is already in operation and has a potential to increase the Booster beam intensity from the PIP design goal by a considerable amount with a reduced beam emittance and beam loss. In this paper, we will present results from our experience from the new scheme in operation, current status and future plans.

  8. Intensity Moments of Hermite-Cosh-Gaussian Laser Beams

    Institute of Scientific and Technical Information of China (English)

    YU Song; GUO Hong; FU Xiquan

    2002-01-01

    In this paper,attention is focused on the intensity moments of the Hermite-Cosh-Gaussian (HChG) laser beams from the zero-order to the fourth-order.The frequently used parameters such as the power in bucket (PIB),the beam width,the curvature radius,the far field divergence,the M2-factor,the Rayleigh length and the kurtosis are calculated in terms of the intensity moments.Figures show the influence of the mode index and the decentered parameter,which are the critical parameters of the HChG beams.Moreover,the center of the gravity of the radiation field and the symmetry are discussed along with the propagation axis.Finally,the power fraction within the beam width defined by the second moments is illustrated with numerical method.

  9. Three-dimensional multispecies nonlinear perturbative particle simulations of collective processes in intense particle beams

    Directory of Open Access Journals (Sweden)

    Hong Qin

    2000-08-01

    Full Text Available Collective processes in intense charged particle beams described self-consistently by the Vlasov-Maxwell equations are studied using a 3D multispecies nonlinear perturbative particle simulation method. The newly developed beam equilibrium, stability, and transport (BEST code is used to simulate the nonlinear stability properties of intense beam propagation, surface eigenmodes in a high-intensity beam, and the electron-proton (e-p two-stream instability observed in the Proton Storage Ring (PSR experiment. Detailed simulations in a parameter regime characteristic of the PSR experiment show that the dipole-mode two-stream instability is stabilized by a modest spread (about 0.1% in axial momentum of the beam particles.

  10. Achromatic beam transport of High Current Injector

    Science.gov (United States)

    Kumar, Sarvesh; Mandal, A.

    2016-02-01

    The high current injector (HCI) provides intense ion beams of high charge state using a high temperature superconducting ECR ion source. The ion beam is accelerated upto a final energy of 1.8 MeV/u due to an electrostatic potential, a radio frequency quadrupole (RFQ) and a drift tube linac (DTL). The ion beam has to be transported to superconducting LINAC which is around 50 m away from DTL. This section is termed as high energy beam transport section (HEBT) and is used to match the beam both in transverse and longitudinal phase space to the entrance of LINAC. The HEBT section is made up of four 90 deg. achromatic bends and interconnecting magnetic quadrupole triplets. Two RF bunchers have been used for longitudinal phase matching to the LINAC. The ion optical design of HEBT section has been simulated using different beam dynamics codes like TRACEWIN, GICOSY and TRACE 3D. The field computation code OPERA 3D has been utilized for hardware design of all the magnets. All the dipole and quadrupole magnets have been field mapped and their test results such as edge angles measurements, homogeneity and harmonic analysis etc. are reported. The whole design of HEBT section has been performed such that the most of the beam optical components share same hardware design and there is ample space for beam diagnostics as per geometry of the building. Many combination of achromatic bends have been simulated to transport the beam in HEBT section but finally the four 90 deg. achromatic bend configuration is found to be the best satisfying all the geometrical constraints with simplified beam tuning process in real time.

  11. Intense DC beam nonlinear transport-analysis & simulation

    Institute of Scientific and Technical Information of China (English)

    L(U) Jian-Qin; ZHAO Xiao-Song

    2009-01-01

    The intense dc beam nonlinear transport was analyzed with the Lie algebraic method,and the particle trajectories of the second order approximation were obtained.Based on the theoretical analysis a computer code was designed.To get self-consistent solutions,iteration procedures were used in the code.As an example,we calculated a beam line(drift-electrostatic quadrupole doublet-drift).The results agree to the results calculated by using the PIC method.

  12. Development of high quality electron beam accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Kando, Masaki; Dewa, Hideki; Kotaki, Hideyuki; Kondo, Shuji; Hosokai, Tomonao; Kanazawa, Shuhei; Yokoyama, Takashi; Nakajima, Kazuhisa [Advanced Photon Research Center, Kansai Research Establishment, Japan Atomic Energy Research Institute, Kizu, Kyoto (Japan)

    2000-03-01

    A design study on a high quality electron beam accelerator is described. This accelerator will be used for second generation experiments of laser wakefield acceleration, short x-ray generation, and other experiments of interaction of high intensity laser with an electron beam at Advanced Photon Research Center, Kansai Research Establishment, Japan Atomic Energy Research Institute. The system consists of a photocathode rf gun and a race-track microtron (RTM). To combine these two components, injection and extraction beamlines are designed employing transfer matrix and compute codes. A present status of the accelerator system is also presented. (author)

  13. Improving the intensity of a focused laser beam

    Science.gov (United States)

    Haddadi, Sofiane; Fromager, Michael; Louhibi, Djelloul; Hasnaoui, Abdelkrim; Harfouche, Ali; Cagniot, Emmanuel; ńit-Ameur, Kamel

    2015-03-01

    Let us consider the family of symmetrical Laguerre-Gaus modes of zero azimuthal order which will be denoted as LGp0 . The latter is made up of central lobe surrounded by p concentric rings of light. The fundamental mode LG00 is a Gaussian beam of width W. The focusing of a LGp0 beam of power P by a converging lens of focal length f produces a focal spot keeping the LGp0 -shape and having a central intensity I0= 2PW2/(λf)2 whatever the value of the radial order p. Many applications of lasers (laser marking, laser ablation, …) seek nowadays for a focal laser spot with the highest as possible intensity. For a given power P, increasing intensity I0 can be achieved by increasing W and reducing the focal length f. However, this way of doing is in fact limited because the ratio W/f cannot increase indefinitely at the risk of introducing a huge truncation upon the edge of the lens. In fact, it is possible to produce a single-lobed focal spot with a central intensity of about p times the intensity I0. This result has been obtained by reshaping (rectification) a LGp0 beam thanks to a proper Binary Diffractive Optical Element (BDOE). In addition, forcing a laser cavity to oscillate upon a LGp0 can improve the power extract due to a mode volume increasing with the mode order p. This could allow envisaging an economy of scale in term of laser pumping power for producing a given intensity I0. In addition, we have demonstrated that a rectified LGp0 beam better stand the lens spherical aberration than the usual Gaussian beam.

  14. High Precision Electon Beam Polarimetry

    National Research Council Canada - National Science Library

    Dutta, D

    2016-01-01

    Over the last three decades high precision electron beam polarimetry has been at the fore-front of progress made in leveraging the spin degrees of freedom in nuclear and particle physics experiments...

  15. Linac design for intense hadron beams

    OpenAIRE

    Zhang, Chuan

    2010-01-01

    Energy and environment are two major concerns in the 21st century. At present, the energy required for the daily life still mainly relies on the traditional fossil fuel resources, but the caused air pollution problem and greenhouse effect have seriously threatened the sustainable development of mankind. Another adopted energy source which can provide a large fraction of electricity for the world is the nuclear fission reaction. However, the increasing high-radioactive spent nuclear fuels, whi...

  16. Beam Diagnostics Instrumentation for the High Energy Beam Transport Line of I.P.H.I.

    CERN Document Server

    Ausset, P; Coacolo, J L; Lesrel, J; Maymon, J N; Olivier, A; Rouviere, N; Solal-Cohen, M; Vatrinet, L; Yaniche, J F

    2005-01-01

    I.P.H.I. is a High Intensity Proton Injector under construction at Saclay (C.N.R.S/ I.N.2P.3; C.E.A. / D.A.P.N.I.A and C.E.R.N. collaboration). An E.C.R. produces a 100 keV, 100 mA C.W. proton beam which will be accelerated at 3 MeV by a 4 vanes R.F.Q. operating at 352.2 MHz. Finally, a High Energy Beam Transport Line (H.E.B.T.) will deliver the beam to a beam stopper and will be equipped with appropriate beam diagnostics to carry intensity; centroïd beam transverse position, transverse beam profiles, beam energy and energy spread measurements for the commissioning of I.P.H.I. These beam diagnostics will operate under both pulsed and C.W. operation. Transverse beam profile measurements will be acquired under low and high duty factor pulsed beam operation using a slow wire scanner and a C.C.D. camera to image the beam-induced fluorescence. The beam instrumentation of the H.E.B.T. is reviewed and preliminary obtained transverse profile measurements at 100 keV are described.

  17. Beam diagnostics instrumentation for the high energy beam transfer line of I.P.H.I

    Energy Technology Data Exchange (ETDEWEB)

    Ausset, P.; Berthelot, S.; Coacolo, J.L.; Lesrel, J.; Maymon, J.N.; Olivier, A.; Rouviere, N.; Solal, M.; Vatrinet, L.; Yaniche, J.F. [Institut de Physique Nucleaire, (IN2P3/CNRS) 91 - Orsay (France); Belyaev, G.; Roudskoy, I. [I.T.E.P. Moscow (Russian Federation)

    2005-07-01

    I.P.H.I. is a High Intensity Proton Injector under construction at Saclay. An E.C.R. source produces a 100 keV, 100 mA C.W. proton beam which will be accelerated at 3 MeV by a 4 vanes R.F.Q. operating at 352.2 MHz. Finally, a High Energy Beam Transport Line (H.E.B.T.) will deliver the beam to a beam stopper and will be equipped with appropriate beam diagnostics to carry intensity, centroid beam transverse position, transverse beam profiles, beam energy and energy spread measurements for the commissioning of I.P.H.I. These beam diagnostics will operate under both pulsed and C.W. operation. Transverse beam profile measurements will be acquired under low and high duty factor pulsed beam operation using a slow wire scanner and a C.C.D. camera to image the beam-induced fluorescence. The beam instrumentation of the H.E.B.T. is reviewed and preliminary obtained transverse profile measurements at 100 keV are described. (authors)

  18. High-Intensity, High Charge-State Heavy Ion Sources

    CERN Document Server

    Alessi, J

    2004-01-01

    There are many accelerator applications for high intensity heavy ion sources, with recent needs including dc beams for RIA, and pulsed beams for injection into synchrotrons such as RHIC and LHC. The present status of sources producing high currents of high charge state heavy ions will be reviewed. These sources include ECR, EBIS, and Laser ion sources. The benefits and limitations for these type sources will be described, for both dc and pulsed applications. Possible future improvements in these type sources will also be discussed.

  19. The use the a high intensity neutrino beam from the ESS proton linac for measurement of neutrino CP violation and mass hierarchy

    CERN Document Server

    Baussan, E.; Ekelof, T.; Martinez, E.Fernandez; Ohman, H.; Vassilopoulos, N.

    2012-01-01

    It is proposed to complement the ESS proton linac with equipment that would enable the production, concurrently with the production of the planned ESS beam used for neutron production, of a 5 MW beam of 10$^{23}$ 2.5 GeV protons per year in microsecond short pulses to produce a neutrino Super Beam, and to install a megaton underground water Cherenkov detector in a mine to detect $\

  20. Phase rotation of muon beams for producing intense low-energy muon beams

    CERN Document Server

    Neuffer, D; Hansen, G

    2016-01-01

    Low-energy muon beams are useful for rare decay searches, which provide access to new physics that cannot be addressed at high-energy colliders. However, muons are produced within a broad energy spread unmatched to the low-energy required. In this paper we outline a phase rotation method to significantly increase the intensity of low-energy muons. The muons are produced from a short pulsed proton driver, and develop a time-momentum correlation in a drift space following production. A series of rf cavities is used to bunch the muons and phase-energy rotate the bunches to a momentum of around 100 MeV/c. Then another group of rf cavities is used to decelerate the muon bunches to low-energy. This obtains ~0.1 muon per 8 GeV proton, which is significantly higher than currently planned Mu2e experiments, and would enable a next generation of rare decay searches, and other intense muon beam applications.

  1. Phase Rotation of Muon Beams for Producing Intense Low-Energy Muon Beams

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, D. [Fermilab; Bao, Y. [UC, Riverside; Hansen, G. [UC, Riverside

    2016-01-01

    Low-energy muon beams are useful for rare decay searches, which provide access to new physics that cannot be addressed at high-energy colliders. However, muons are produced within a broad energy spread unmatched to the low-energy required. In this paper we outline a phase rotation method to significantly increase the intensity of low-energy muons. The muons are produced from a short pulsed proton driver, and develop a time-momentum correlation in a drift space following production. A series of rf cavities is used to bunch the muons and phase-energy rotate the bunches to a momentum of around 100 MeV/c. Then another group of rf cavities is used to decelerate the muon bunches to low-energy. This obtains ~0.1 muon per 8 GeV proton, which is significantly higher than currently planned Mu2e experiments, and would enable a next generation of rare decay searches, and other intense muon beam applications.

  2. Fast Beam Intensity Measurements for the LHC

    CERN Document Server

    Belohrad, D

    Particle accelerators are constructed and operated for a wide variety of applications. In particle physics - the branch of physics that studies the elementary constituents of matter and forces between them - high energy accelerators are used to look deep into the structure of matter. Medical particle accelerators are used for example in medicine to treat tumours [31], in imaging techniques such as Positron Emission Tomography (PET) [24], or for the radio-isotopes production. They also serve in many other industrial branches, e.g. geology, radiocarbon dating [39], molecular complex spectroscopy, lithography, food preservation etc. The eld of accelerator technology draws knowledge and expertise from a wide range of scientic disciplines and uses the latest technical knowledge. The incomplete list of covered disciplines includes mathematics, physics, electronics, computing, electromagnetic eld technology, microwave technology, cryogenics, vacuum technology, special materials, mechanical engineering or civil engin...

  3. High intensity neutrino oscillation facilities in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Edgecock, T. R.; Caretta, O.; Davenne, T.; Densam, C.; Fitton, M.; Kelliher, D.; Loveridge, P.; Machida, S.; Prior, C.; Rogers, C.; Rooney, M.; Thomason, J.; Wilcox, D.; Wildner, E.; Efthymiopoulos, I.; Garoby, R.; Gilardoni, S.; Hansen, C.; Benedetto, E.; Jensen, E.; Kosmicki, A.; Martini, M.; Osborne, J.; Prior, G.; Stora, T.; Melo Mendonca, T.; Vlachoudis, V.; Waaijer, C.; Cupial, P.; Chancé, A.; Longhin, A.; Payet, J.; Zito, M.; Baussan, E.; Bobeth, C.; Bouquerel, E.; Dracos, M.; Gaudiot, G.; Lepers, B.; Osswald, F.; Poussot, P.; Vassilopoulos, N.; Wurtz, J.; Zeter, V.; Bielski, J.; Kozien, M.; Lacny, L.; Skoczen, B.; Szybinski, B.; Ustrycka, A.; Wroblewski, A.; Marie-Jeanne, M.; Balint, P.; Fourel, C.; Giraud, J.; Jacob, J.; Lamy, T.; Latrasse, L.; Sortais, P.; Thuillier, T.; Mitrofanov, S.; Loiselet, M.; Keutgen, Th.; Delbar, Th.; Debray, F.; Trophine, C.; Veys, S.; Daversin, C.; Zorin, V.; Izotov, I.; Skalyga, V.; Burt, G.; Dexter, A. C.; Kravchuk, V. L.; Marchi, T.; Cinausero, M.; Gramegna, F.; De Angelis, G.; Prete, G.; Collazuol, G.; Laveder, M.; Mazzocco, M.; Mezzetto, M.; Signorini, C.; Vardaci, E.; Di Nitto, A.; Brondi, A.; La Rana, G.; Migliozzi, P.; Moro, R.; Palladino, V.; Gelli, N.; Berkovits, D.; Hass, M.; Hirsh, T. Y.; Schaumann, M.; Stahl, A.; Wehner, J.; Bross, A.; Kopp, J.; Neuffer, D.; Wands, R.; Bayes, R.; Laing, A.; Soler, P.; Agarwalla, S. K.; Cervera Villanueva, A.; Donini, A.; Ghosh, T.; Gómez Cadenas, J. J.; Hernández, P.; Martín-Albo, J.; Mena, O.; Burguet-Castell, J.; Agostino, L.; Buizza-Avanzini, M.; Marafini, M.; Patzak, T.; Tonazzo, A.; Duchesneau, D.; Mosca, L.; Bogomilov, M.; Karadzhov, Y.; Matev, R.; Tsenov, R.; Akhmedov, E.; Blennow, M.; Lindner, M.; Schwetz, T.; Fernández Martinez, E.; Maltoni, M.; Menéndez, J.; Giunti, C.; González García, M. C.; Salvado, J.; Coloma, P.; Huber, P.; Li, T.; López Pavón, J.; Orme, C.; Pascoli, S.; Meloni, D.; Tang, J.; Winter, W.; Ohlsson, T.; Zhang, H.; Scotto-Lavina, L.; Terranova, F.; Bonesini, M.; Tortora, L.; Alekou, A.; Aslaninejad, M.; Bontoiu, C.; Kurup, A.; Jenner, L. J.; Long, K.; Pasternak, J.; Pozimski, J.; Back, J. J.; Harrison, P.; Beard, K.; Bogacz, A.; Berg, J. S.; Stratakis, D.; Witte, H.; Snopok, P.; Bliss, N.; Cordwell, M.; Moss, A.; Pattalwar, S.; Apollonio, M.

    2013-02-01

    The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fr\\'ejus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of {\\mu}+ and {\\mu}- beams in a storage ring. The far detector in this case is a 100 kt Magnetised Iron Neutrino Detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fr\\'ejus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive.

  4. Correction of linear-array lidar intensity data using an optimal beam shaping approach

    Science.gov (United States)

    Xu, Fan; Wang, Yuanqing; Yang, Xingyu; Zhang, Bingqing; Li, Fenfang

    2016-08-01

    The linear-array lidar has been recently developed and applied for its superiority of vertically non-scanning, large field of view, high sensitivity and high precision. The beam shaper is the key component for the linear-array detection. However, the traditional beam shaping approaches can hardly satisfy our requirement for obtaining unbiased and complete backscattered intensity data. The required beam distribution should roughly be oblate U-shaped rather than Gaussian or uniform. Thus, an optimal beam shaping approach is proposed in this paper. By employing a pair of conical lenses and a cylindrical lens behind the beam expander, the expanded Gaussian laser was shaped to a line-shaped beam whose intensity distribution is more consistent with the required distribution. To provide a better fit to the requirement, off-axis method is adopted. The design of the optimal beam shaping module is mathematically explained and the experimental verification of the module performance is also presented in this paper. The experimental results indicate that the optimal beam shaping approach can effectively correct the intensity image and provide ~30% gain of detection area over traditional approach, thus improving the imaging quality of linear-array lidar.

  5. High intensity polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, C.K.

    1980-10-01

    The status of the polarized electron source development program at SLAC will be reviewed. Emission currents of 60 A, corresponding to a space charge limited current density of 180 A/cm/sup 2/, have been obtained from GaAs photocathodes. Electron beam polarization 20% greater than that obtainable from GaAs cathodes has been observed from multilayer GaAs-GaAlAs structures. Work in progress to produce high beam polarization from II-IV-V/sub 2/ chalcopyrite photocathodes will also be described.

  6. LHC Beam Instrumentation: Beam Position and Intensity Measurements (1/3)

    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.

  7. Commissioning and first results of the Intense Beam EXperiment (IBEX) linear Paul trap

    Science.gov (United States)

    Sheehy, S. L.; Carr, E. J.; Martin, L. K.; Budzik, K.; Kelliher, D. J.; Machida, S.; Prior, C. R.

    2017-07-01

    The Intense Beam Experiment (IBEX) is a linear Paul trap designed to replicate the dynamics of intense particle beams in accelerators. Similar to the S-POD apparatus at Hiroshima University, IBEX is a small scale experiment which has been constructed and recently commissioned at the STFC Rutherford Appleton Laboratory in the UK. The aim of the experiment is to support theoretical studies of next-generation high intensity proton and ion accelerators, complementing existing computer simulation approaches. Here we report on the status of commissioning and first results obtained.

  8. CERN Accelerator School: Intensity Limitations in Particle Beams | 2-11 November

    CERN Multimedia

    2015-01-01

    Registration is now open for the CERN Accelerator School’s specialised course on Intensity Limitations in Particle Beams, to be held at CERN between 2 and 11 November 2015.   This course will mainly be of interest to staff in accelerator laboratories, university departments and companies manufacturing accelerator equipment. Many accelerators and storage rings, whether intended for particle physics experiments, synchrotron light sources or industrial applications, require beams of high brightness and the highest possible intensities. A good understanding of the possible limitations is required to achieve the desired performance. The programme for this course will cover the interaction of beams with their surroundings, with other beams and further collective effects. Lectures on the effects and possible mitigations will be complemented by tutorials. Further information can be found at: http://cas.web.cern.ch/cas/Intensity-Limitations-2015/IL-advert.html   http:/...

  9. High-Intensity Proton Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Jay L. Hirshfield

    2011-12-27

    Analysis is presented for an eight-cavity proton cyclotron accelerator that could have advantages as compared with other accelerators because of its potentially high acceleration gradient. The high gradient is possible since protons orbit in a sequence of TE111 rotating mode cavities of equally diminishing frequencies with path lengths during acceleration that greatly exceed the cavity lengths. As the cavities operate at sequential harmonics of a basic repetition frequency, phase synchronism can be maintained over a relatively wide injection phase window without undue beam emittance growth. It is shown that use of radial vanes can allow cavity designs with significantly smaller radii, as compared with simple cylindrical cavities. Preliminary beam transport studies show that acceptable extraction and focusing of a proton beam after cyclic motion in this accelerator should be possible. Progress is also reported on design and tests of a four-cavity electron counterpart accelerator for experiments to study effects on beam quality arising from variations injection phase window width. This device is powered by four 500-MW pulsed amplifiers at 1500, 1800, 2100, and 2400 MHz that provide phase synchronous outputs, since they are driven from a with harmonics derived from a phase-locked 300 MHz source.

  10. Intense ion-beam dynamics in the NICA collider

    Science.gov (United States)

    Kozlov, O. S.; Meshkov, I. N.; Sidorin, A. O.; Trubnikov, G. V.

    2016-12-01

    The problems of intense ion-beam dynamics in the developed and optimized optical structure of the NICA collider are considered. Conditions for beam collisions and obtaining the required parameters of luminosity in the operation energy range are discussed. The restriction on collider luminosity is related to effects of the domination of the space charge and intrabeam scattering. Applying methods of cooling, electron and stochastic ones, will permit one to suppress these effects and reach design luminosity. The work also deals with systems of magnetic field correction and problems of calculating the dynamic aperture of the collider.

  11. High intensity neutrino oscillation facilities in Europe

    CERN Document Server

    Edgecock, T R; Davenne, T; Densham, C; Fitton, M; Kelliher, D; Loveridge, P; Machida, S; Prior, C; Rogers, C; Rooney, M; Thomason, J; Wilcox, D; Wildner, E; Efthymiopoulos, I; Garoby, R; Gilardoni, S; Hansen, C; Benedetto, E; Jensen, E; Kosmicki, A; Martini, M; Osborne, J; Prior, G; Stora, T; Melo-Mendonca, T; Vlachoudis, V; Waaijer, C; Cupial, P; Chancé, A; Longhin, A; Payet, J; Zito, M; Baussan, E; Bobeth, C; Bouquerel, E; Dracos, M; Gaudiot, G; Lepers, B; Osswald, F; Poussot, P; Vassilopoulos, N; Wurtz, J; Zeter, V; Bielski, J; Kozien, M; Lacny, L; Skoczen, B; Szybinski, B; Ustrycka, A; Wroblewski, A; Marie-Jeanne, M; Balint, P; Fourel, C; Giraud, J; Jacob, J; Lamy, T; Latrasse, L; Sortais, P; Thuillier, T; Mitrofanov, S; Loiselet, M; Keutgen, Th; Delbar, Th; Debray, F; Trophine, C; Veys, S; Daversin, C; Zorin, V; Izotov, I; Skalyga, V; Burt, G; Dexter, A C; Kravchuk, V L; Marchi, T; Cinausero, M; Gramegna, F; De Angelis, G; Prete, G; Collazuol, G; Laveder, M; Mazzocco, M; Mezzetto, M; Signorini, C; Vardaci, E; Di Nitto, A; Brondi, A; La Rana, G; Migliozzi, P; Moro, R; Palladino, V; Gelli, N; Berkovits, D; Hass, M; Hirsh, T Y; Schaumann, M; Stahl, A; Wehner, J; Bross, A; Kopp, J; Neuffer, D; Wands, R; Bayes, R; Laing, A; Soler, P; Agarwalla, S K; Villanueva, A Cervera; Donini, A; Ghosh, T; Cadenas, J J Gómez; Hernández, P; Martín-Albo, J; Mena, O; Burguet-Castell, J; Agostino, L; Buizza-Avanzini, M; Marafini, M; Patzak, T; Tonazzo, A; Duchesneau, D; Mosca, L; Bogomilov, M; Karadzhov, Y; Matev, R; Tsenov, R; Akhmedov, E; Blennow, M; Lindner, M; Schwetz, T; Martinez, E Fernández; Maltoni, M; Menéndez, J; Giunti, C; García, M C González; Salvado, J; Coloma, P; Huber, P; Li, T; López-Pavón, J; Orme, C; Pascoli, S; Meloni, D; Tang, J; Winter, W; Ohlsson, T; Zhang, H; Scotto-Lavina, L; Terranova, F; Bonesini, M; Tortora, L; Alekou, A; Aslaninejad, M; Bontoiu, C; Kurup, A; Jenner, L J; Long, K; Pasternak, J; Pozimski, J; Back, J J; Harrison, P; Beard, K; Bogacz, A; Berg, J S; Stratakis, D; Witte, H; Snopok, P; Bliss, N; Cordwell, M; Moss, A; Pattalwar, S; Apollonio, M

    2013-01-01

    The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fr\\'ejus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of {\\mu}+ and {\\mu}- beams in a storage ring. The far detector in this case is a 100 kt Magnetised Iron Neutrino Detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fr\\'ejus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the ph...

  12. High intensity neutrino oscillation facilities in Europe

    CERN Document Server

    Edgecock, T.R.; Davenne, T.; Densham, C.; Fitton, M.; Kelliher, D.; Loveridge, P.; Machida, S.; Prior, C.; Rogers, C.; Rooney, M.; Thomason, J.; Wilcox, D.; Wildner, E.; Efthymiopoulos, I.; Garoby, R.; Gilardoni, S.; Hansen, C.; Benedetto, E.; Jensen, E.; Kosmicki, A.; Martini, M.; Osborne, J.; Prior, G.; Stora, T.; Melo-Mendonca, T.; Vlachoudis, V.; Waaijer, C.; Cupial, P.; Chancé, A.; Longhin, A.; Payet, J.; Zito, M.; Baussan, E.; Bobeth, C.; Bouquerel, E.; Dracos, M.; Gaudiot, G.; Lepers, B.; Osswald, F.; Poussot, P.; Vassilopoulos, N.; Wurtz, J.; Zeter, V.; Bielski, J.; Kozien, M.; Lacny, L.; Skoczen, B.; Szybinski, B.; Ustrzycka, A.; Wroblewski, A.; Marie-Jeanne, M.; Balint, P.; Fourel, C.; Giraud, J.; Jacob, J.; Lamy, T.; Latrasse, L.; Sortais, P.; Thuillier, T.; Mitrofanov, S.; Loiselet, M.; Keutgen, Th.; Delbar, Th.; Debray, F.; Trophine, C.; Veys, S.; Daversin, C.; Zorin, V.; Izotov, I.; Skalyga, V.; Burt, G.; Dexter, A.C.; Kravchuk, V.L.; Marchi, T.; Cinausero, M.; Gramegna, F.; De Angelis, G.; Prete, G.; Collazuol, G.; Laveder, M.; Mazzocco, M.; Mezzetto, M.; Signorini, C.; Vardaci, E.; Di Nitto, A.; Brondi, A.; La Rana, G.; Migliozzi, P.; Moro, R.; Palladino, V.; Gelli, N.; Berkovits, D.; Hass, M.; Hirsh, T.Y.; Schaumann, M.; Stahl, A.; Wehner, J.; Bross, A.; Kopp, J.; Neuffer, D.; Wands, R.; Bayes, R.; Laing, A.; Soler, P.; Agarwalla, S.K.; Cervera Villanueva, A.; Donini, A.; Ghosh, T.; Gómez Cadenas, J.J.; Hernández, P.; Martín-Albo, J.; Mena, O.; Burguet-Castell, J.; Agostino, L.; Buizza-Avanzini, M.; Marafini, M.; Patzak, T.; Tonazzo, A.; Duchesneau, D.; Mosca, L.; Bogomilov, M.; Karadzhov, Y.; Matev, R.; Tsenov, R.; Akhmedov, E.; Blennow, M.; Lindner, M.; Schwetz, T.; Fernández Martinez, E.; Maltoni, M.; Menéndez, J.; Giunti, C.; González García, M. C.; Salvado, J.; Coloma, P.; Huber, P.; Li, T.; López-Pavón, J.; Orme, C.; Pascoli, S.; Meloni, D.; Tang, J.; Winter, W.; Ohlsson, T.; Zhang, H.; Scotto-Lavina, L.; Terranova, F.; Bonesini, M.; Tortora, L.; Alekou, A.; Aslaninejad, M.; Bontoiu, C.; Kurup, A.; Jenner, L.J.; Long, K.; Pasternak, J.; Pozimski, J.; Back, J.J.; Harrison, P.; Beard, K.; Bogacz, A.; Berg, J.S.; Stratakis, D.; Witte, H.; Snopok, P.; Bliss, N.; Cordwell, M.; Moss, A.; Pattalwar, S.; Apollonio, M.

    2013-02-20

    The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fr\\'ejus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of {\\mu}+ and {\\mu}- beams in a storage ring. The far detector in this case is a 100 kt Magnetised Iron Neutrino Detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fr\\'ejus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the ph...

  13. Propagation of Plasma Generated by Intense Pulsed Ion Beam Irradiation

    Institute of Scientific and Technical Information of China (English)

    WU Di; GONG Ye; LIU Jin-Yuan; WANG Xiao-Gang; LIU Yue; MA Teng-Cai

    2006-01-01

    @@ Taking the calculation results based on the established two-dimensional ablation model of the intense-pulsed-ion-beam (IPIB) irradiation process as initial conditions, we build a two-dimensional hydrodynamic ejection model of plasma produced by an IPIB-irradiated metal titanium target into ambient gas. We obtain the conclusions that shock waves generate when the background pressure is around 133 mTorr and also obtain the plume splitting phenomenon that has been observed in the experiments.

  14. Active beam integrator for high power coherent lasers

    Energy Technology Data Exchange (ETDEWEB)

    Laguarta, F.; Armengol, J.; Vega, F.; Lupon, N. [Univ. Politecnica de Catalunya, Terrassa (Spain). Dept. d`Optica i Optometria

    1996-12-31

    In laser materials processing applications it is often necessary to work with uniform intensity distributions. This goal is quite difficult to achieve when dealing with high power laser beams, and becomes critical for a successful application involving surface heat treatment of non-metallic materials. The authors have designed and tested a very simple beam shaper for transforming the initial intensity distribution of a CO{sub 2} laser beam mode into a more uniform intensity profile. The beam shaper is a two-faceted mirror for active integration of high power coherent laser beams. After reflection in the faceted mirror, a TEM00 or TEM01 CO{sub 2} laser beam is divided into two beamlets that overlap to give a more uniform intensity distribution. A sharp interference pattern due to the high spatial coherence of the incident beam appears. This interference pattern is actively integrated by a high-frequency longitudinal displacement of one of the facets. This provides a change in the relative phase of the two beamlets, and consequently the interference pattern vibrates and its contribution to the intensity distribution averages out. When sweeping this distribution over a sample, a uniform amount of energy is deposited at every point of its surface. It must be emphasized that unlike multifaceted mirrors, the two-facet integrator may provide uniform intensity profiles over any working distance. Finally, as in other integration devices an imaging system may be used to obtain a spot of the shape and the size desired for a particular application.

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

    CERN Document Server

    Lee, S; Ikegami, M; Toyama, T

    2005-01-01

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

  16. SECRAL在18GHz频率下产生强流高电荷态离子束的初步结果%First Results of SECRAL at 18GHz for Intense Beam Production of Highly Charged Ions

    Institute of Scientific and Technical Information of China (English)

    赵红卫; 何伟; 宋明涛; 李锡霞; 曹云; 王辉; 马宝华; 卢旺; 詹文龙; 魏宝文; 孙良亭; 郭晓虹; 张雪珍; 张子民; 袁平; D.Z.Xie; 李锦钰; 冯玉成

    2007-01-01

    A Superconducting ECR ion source with Advanced design in Lanzhou(SECRAL)was successfully built to produce intense beams of highly charged ions for Heavy Ion Research Facility in Lanzhou(HIRFL).The ion source has been optimized to be operated at 28GHz for its maximum performance.The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping.For 28GHz operation,the magnet assembly can produce peak mirror fields on axis 3.6T at injection.2.2T at extraction and a radial sextupole field of 2.0T at plasma chamber wall.A unique feature of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils.During the ongoing commissioning phase at 18GHz with a stainless steel chamber,tests with various gases and some metals have been conducted with microwave power less than 3.2kW and it turned out the performance is very promising.Some record ion beam intensities have been produced,for instance,810eμof O7+,505eμA of Xe 20+,306eμA of Xe27+,21eμA of Xe34+,2.4eμA of Xe38+ and so on.To reach better results for highly charged ion beams,further modifications such as an aluminium chamber with better cooling,higher microwave power and a movable extraction system will be done,and also emittance measurements are being prepared.

  17. Nonlinear delta f Simulations of Collective Effects in Intense Charged Particle Beams

    CERN Document Server

    Hong Qi

    2003-01-01

    A nonlinear delta(f) particle simulation method based on the Vlasov-Maxwell equations has been recently developed to study collective processes in high-intensity beams, where space-charge and magnetic self-field effects play a critical role in determining the nonlinear beam dynamics. Implemented in the Beam Equilibrium, Stability and Transport (BEST) code [H. Qin, R.C. Davidson, and W.W. Lee, Physical Review -- Special Topics on Accelerator and Beams 3 (2000) 084401; 3 (2000) 109901.], the nonlinear delta(f) method provides a low-noise and self-consistent tool for simulating collective interactions and nonlinear dynamics of high-intensity beams in modern and next-generation accelerators and storage rings, such as the Spallation Neutron Source and heavy ion fusion drivers. A wide range of linear eigenmodes of high-intensity charged-particle beams can be systematically studied using the BEST code. Simulation results for the electron-proton two-stream instability in the Proton Storage Ring experiment [R. Macek, ...

  18. High performance computing for beam physics applications

    Science.gov (United States)

    Ryne, R. D.; Habib, S.

    Several countries are now involved in efforts aimed at utilizing accelerator-driven technologies to solve problems of national and international importance. These technologies have both economic and environmental implications. The technologies include waste transmutation, plutonium conversion, neutron production for materials science and biological science research, neutron production for fusion materials testing, fission energy production systems, and tritium production. All of these projects require a high-intensity linear accelerator that operates with extremely low beam loss. This presents a formidable computational challenge: One must design and optimize over a kilometer of complex accelerating structures while taking into account beam loss to an accuracy of 10 parts per billion per meter. Such modeling is essential if one is to have confidence that the accelerator will meet its beam loss requirement, which ultimately affects system reliability, safety and cost. At Los Alamos, the authors are developing a capability to model ultra-low loss accelerators using the CM-5 at the Advanced Computing Laboratory. They are developing PIC, Vlasov/Poisson, and Langevin/Fokker-Planck codes for this purpose. With slight modification, they have also applied their codes to modeling mesoscopic systems and astrophysical systems. In this paper, they will first describe HPC activities in the accelerator community. Then they will discuss the tools they have developed to model classical and quantum evolution equations. Lastly they will describe how these tools have been used to study beam halo in high current, mismatched charged particle beams.

  19. High intensity neutrino oscillation facilities in Europe

    Directory of Open Access Journals (Sweden)

    T. R. Edgecock

    2013-02-01

    Full Text Available The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fréjus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of μ^{+} and μ^{-} beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular ^{6}He and ^{18}Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fréjus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive.

  20. High intensity specular reflectometry - first experiments

    CERN Document Server

    Stahn, J; Panzner, T

    2011-01-01

    Selene is the attempt to implement a new scheme for high-intensity specular reflectometry. Instead of a highly collimated beam one uses a convergent beam covering a large angular range. The angular resolution is then performed by a position-sensitive detector. Off-specular scattering in this set-up leads to some background, but for screening of wide parameter ranges (e.g. temperature, electric and magnetic fields) the intensity gain of at least one order of magnitude is essential. If necessary, the high precession measurements (even with off-specular components) then are performed with the conventional set-up. The heart of this new set-up is an elliptically focusing guide element of 2\\,m length. Though this guide is optimised for the use on the TOF reflectometer Amor at SINQ, it can be used as stand-alone device to check the possible application also for other neutron scattering techniques. The first measurements on AMOR confirmed the general concept and the various operation modes. A draw-back occurred due t...

  1. Current Measurements of Low-Intensity Beams at CRYRING

    CERN Document Server

    Paál, A; Källberg, A

    2003-01-01

    The demand for new ion species leads to an increasing number of cases in which the ions can only be produced in small quantities. Thus, weak ion currents quite often have to be handled in low energy ion storage ring, like CRYRING. Various detector systems have been developed to measure such low intensity coasting and bunched beams by using the overlapping ranges of those systems. We have extended the RMS resolution to 1 nA of the Bergoz Beam Charge Monitor (BCM) by using a low noise 60 dB preamplifier for the Integrating Current Transformer. The sum signal of a capacitive pick-up is integrated by a second gated integrator and the BCM output signal is used for calibration. The RMS resolution is about 100 pA.. To measure the coasting beam intensity, neutral particle detectors have been built. The fast Microchannel plate detector can handle 1 Mc/s, and a 50 Mc/s Secondary Electron Multiplier based detector is under construction. On the magnetic flat top, a time of 100 ms is available to calibrate the count r...

  2. Modeling nitrogen plasmas produced by intense electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Angus, J. R.; Swanekamp, S. B.; Schumer, J. W.; Hinshelwood, D. D. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Mosher, D.; Ottinger, P. F. [Independent contractors for NRL through Engility, Inc., Alexandria, Virginia 22314 (United States)

    2016-05-15

    A new gas–chemistry model is presented to treat the breakdown of a nitrogen gas with pressures on the order of 1 Torr from intense electron beams with current densities on the order of 10 kA/cm{sup 2} and pulse durations on the order of 100 ns. For these parameter regimes, the gas transitions from a weakly ionized molecular state to a strongly ionized atomic state on the time scale of the beam pulse. The model is coupled to a 0D–circuit model using the rigid–beam approximation that can be driven by specifying the time and spatial profiles of the beam pulse. Simulation results are in good agreement with experimental measurements of the line–integrated electron density from experiments done using the Gamble II generator at the Naval Research Laboratory. It is found that the species are mostly in the ground and metastable states during the atomic phase, but that ionization proceeds predominantly through thermal ionization of optically allowed states with excitation energies close to the ionization limit.

  3. EBIS/T charge breeding for intense rare isotope beams at MSU

    CERN Document Server

    Schwarz, S; Marrs, R E; Kittimanapun, K; Lapierre, A; Mendez, A J; Ames, F; Beene, J R; Lindroos, M; Ahle, L E; Stracener, D W; Kester, O; Wenander, F; Lopez-Urrutia, J R Crespo; Dilling, J; Bollen, G

    2010-01-01

    Experiments with reaccelerated beams are an essential component of the science program of existing and future rare isotope beam facilities. NSCL is currently constructing ReA3, a reaccelerator for rare isotopes that have been produced by projectile fragmentation and in-flight fission and that have been thermalized in a gas stopper. The resulting low-energy beam will be brought to an Electron Beam Ion Source/Trap (EBIS/T) in order to obtain highly charged ions at an energy of 12 keV/u. This charge breeder is followed by a compact linear accelerator with a maximum beam energy of 3MeV/u for U-238 and higher energies for lighter isotopes. Next-generation rare isotope beam facilities like the Facility for Rare Isotope Beams FRIB, but also existing Isotope Separator On-line (ISOL) facilities are expected to provide rare-isotope beam rates in the order of 10(11) particles per second for reacceleration. At present the most promising scheme to efficiently start the reacceleration of these intense beams is the use of a...

  4. INERTIAL FUSION DRIVEN BY INTENSE HEAVY-ION BEAMS

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, W. M.; Friedman, A.; Grote, D. P.; Barnard, J. J.; Cohen, R. H.; Dorf, M. A.; Lund, S. M.; Perkins, L. J.; Terry, M. R.; Logan, B. G.; Bieniosek, F. M.; Faltens, A.; Henestroza, E.; Jung, J. Y.; Kwan, J. W.; Lee, E. P.; Lidia, S. M.; Ni, P. A.; Reginato, L. L.; Roy, P. K.; Seidl, P. A.; Takakuwa, J. H.; Vay, J.-L.; Waldron, W. L.; Davidson, R. C.; Gilson, E. P.; Kaganovich, I. D.; Qin, H.; Startsev, E.; Haber, I.; Kishek, R. A.; Koniges, A. E.

    2011-03-31

    Intense heavy-ion beams have long been considered a promising driver option for inertial-fusion energy production. This paper briefly compares inertial confinement fusion (ICF) to the more-familiar magnetic-confinement approach and presents some advantages of using beams of heavy ions to drive ICF instead of lasers. Key design choices in heavy-ion fusion (HIF) facilities are discussed, particularly the type of accelerator. We then review experiments carried out at Lawrence Berkeley National Laboratory (LBNL) over the past thirty years to understand various aspects of HIF driver physics. A brief review follows of present HIF research in the US and abroad, focusing on a new facility, NDCX-II, being built at LBNL to study the physics of warm dense matter heated by ions, as well as aspects of HIF target physics. Future research directions are briefly summarized.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-03

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

  6. Photoproduction at High Energy and High Intensity

    CERN Multimedia

    2002-01-01

    The photon beam used for this programme is tagged and provides a large flux up to very high energies (150-200 GeV). It is also hadron-free, since it is obtained by a two-step conversion method. A spectrometer is designed to exploit this beam and to perform a programme of photoproduction with a high level of sensitivity (5-50 events/picobarn).\\\\ \\\\ Priority will be given to the study of processes exhibiting the point-like behaviour of the photon, especially deep inelastic Compton scattering. The spectrometer has two magnets. Charged tracks are measured by MWPC's located only in field-free regions. Three calorimeters provide a large coverage for identifying and measuring electrons and photons. An iron filter downstream identifies muons. Most of the equipment is existing and recuperated from previous experiments.

  7. Microsecond pulse width, intense, light-ion beam accelerator

    Science.gov (United States)

    Rej, D. J.; Bartsch, R. R.; Davis, H. A.; Faehl, R. J.; Greenly, J. B.; Waganaar, W. J.

    1993-10-01

    A relatively long-pulse width (0.1-1 μs) intense ion beam accelerator has been built for materials processing applications. An applied Br, magnetically insulated extraction ion diode with dielectric flashover ion source is installed directly onto the output of a 1.2 MV, 300-kJ Marx generator. The diode is designed with the aid of multidimensional particle-in-cell simulations. Initial operation of the accelerator at 0.4 MV indicates satisfactory performance without the need for additional pulse shaping. The effect of a plasma opening switch on diode behavior is considered.

  8. Cooling of relativistic electron beams in intense laser pulses: Chirps and radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yoffe, S.R., E-mail: sam.yoffe@strath.ac.uk; Noble, A., E-mail: adam.noble@strath.ac.uk; Macleod, A.J., E-mail: alexander.macleod@strath.ac.uk; Jaroszynski, D.A., E-mail: d.a.jaroszynski@strath.ac.uk

    2016-09-01

    Next-generation high-power laser facilities (such as the Extreme Light Infrastructure) will provide unprecedented field intensities, and will allow us to probe qualitatively new physical regimes for the first time. One of the important fundamental questions which will be addressed is particle dynamics when radiation reaction and quantum effects play a significant role. Classical theories of radiation reaction predict beam cooling in the interaction of a relativistic electron bunch and a high-intensity laser pulse, with final-state properties only dependent on the laser fluence. The observed quantum suppression of this cooling instead exhibits a dependence on the laser intensity directly. This offers the potential for final-state properties to be modified or even controlled by tailoring the intensity profile of the laser pulse. In addition to beam properties, quantum effects will be manifest in the emitted radiation spectra, which could be manipulated for use as radiation sources. We compare predictions made by classical, quasi-classical and stochastic theories of radiation reaction, and investigate the influence of chirped laser pulses on the observed radiation spectra. - Highlights: • Classical theories of radiation reaction predict electron beam cooling in high fields. • Quantum effects lead to a reduction in electron beam cooling. • Quasi-classical model agrees with predictions from a single-emission stochastic model. • Negative frequency chirp found to increase photon emission, but not maximum energy.

  9. LATTICES FOR HIGH-POWER PROTON BEAM ACCELERATION AND SECONDARY BEAM COLLECTION AND COOLING.

    Energy Technology Data Exchange (ETDEWEB)

    WANG, S.; WEI, J.; BROWN, K.; GARDNER, C.; LEE, Y.Y.; LOWENSTEIN, D.; PEGGS, S.; SIMOS, N.

    2006-06-23

    Rapid cycling synchrotrons are used to accelerate high-intensity proton beams to energies of tens of GeV for secondary beam production. After primary beam collision with a target, the secondary beam can be collected, cooled, accelerated or decelerated by ancillary synchrotrons for various applications. In this paper, we first present a lattice for the main synchrotron. This lattice has: (a) flexible momentum compaction to avoid transition and to facilitate RF gymnastics (b) long straight sections for low-loss injection, extraction, and high-efficiency collimation (c) dispersion-free straights to avoid longitudinal-transverse coupling, and (d) momentum cleaning at locations of large dispersion with missing dipoles. Then, we present a lattice for a cooler ring for the secondary beam. The momentum compaction across half of this ring is near zero, while for the other half it is normal. Thus, bad mixing is minimized while good mixing is maintained for stochastic beam cooling.

  10. MuSIC: delivering the world's most intense muon beam

    CERN Document Server

    Cook, S; Edmonds, A; Fukuda, M; Hatanaka, K; Hino, Y; Kuno, Y; Lancaster, M; Mori, Y; Ogitsu, T; Sakamoto, H; Sato, A; Tran, N H; Truong, N M; Wing, M; Yamamoto, A; Yoshida, M

    2016-01-01

    A new muon beamline, muon science innovative channel (MuSIC), was set up at the Research Centre for Nuclear Physics (RCNP), Osaka University, in Osaka, Japan, using the 392 MeV proton beam impinging on a target. The production of an intense muon beam relies on the efficient capture of pions, which subsequently decay to muons, using a novel superconducting solenoid magnet system. After the pion-capture solenoid the first $36^\\circ$ of the curved muon transport line was commissioned and the muon flux was measured. In order to detect muons, a target of either copper or magnesium was placed to stop muons at the end of the muon beamline. Two stations of plastic scintillators located upstream and downstream from the muon target were used to reconstruct the decay spectrum of muons. In a complementary method to detect negatively-charged muons, the X-ray spectrum yielded by muonic atoms in the target were measured in a germanium detector. Measurements, at a proton beam current of 6 pA, yielded $(10.4 \\pm 2.7) \\times 1...

  11. Plasma Wakefield Acceleration of an Intense Positron Beam

    Energy Technology Data Exchange (ETDEWEB)

    Blue, B

    2004-04-21

    The Plasma Wakefield Accelerator (PWFA) is an advanced accelerator concept which possess a high acceleration gradient and a long interaction length for accelerating both electrons and positrons. Although electron beam-plasma interactions have been extensively studied in connection with the PWFA, very little work has been done with respect to positron beam-plasma interactions. This dissertation addresses three issues relating to a positron beam driven plasma wakefield accelerator. These issues are (a) the suitability of employing a positron drive bunch to excite a wake; (b) the transverse stability of the drive bunch; and (c) the acceleration of positrons by the plasma wake that is driven by a positron bunch. These three issues are explored first through computer simulations and then through experiments. First, a theory is developed on the impulse response of plasma to a short drive beam which is valid for small perturbations to the plasma density. This is followed up with several particle-in-cell (PIC) simulations which study the experimental parameter (bunch length, charge, radius, and plasma density) range. Next, the experimental setup is described with an emphasis on the equipment used to measure the longitudinal energy variations of the positron beam. Then, the transverse dynamics of a positron beam in a plasma are described. Special attention is given to the way focusing, defocusing, and a tilted beam would appear to be energy variations as viewed on our diagnostics. Finally, the energy dynamics imparted on a 730 {micro}m long, 40 {micro}m radius, 28.5 GeV positron beam with 1.2 x 10{sup 10} particles in a 1.4 meter long 0-2 x 10{sup 14} e{sup -}/cm{sup 3} plasma is described. First the energy loss was measured as a function of plasma density and the measurements are compared to theory. Then, an energy gain of 79 {+-} 15 MeV is shown. This is the first demonstration of energy gain of a positron beam in a plasma and it is in good agreement with the predictions

  12. LEADS-DC: A computer code for intense dc beam nonlinear transport simulation

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    An intense dc beam nonlinear transport code has been developed. The code is written in Visual FORTRAN 6.6 and has ~13000 lines. The particle distribution in the transverse cross section is uniform or Gaussian. The space charge forces are calculated by the PIC (particle in cell) scheme, and the effects of the applied fields on the particle motion are calculated with the Lie algebraic method through the third order approximation. Obviously,the solutions to the equations of particle motion are self-consistent. The results obtained from the theoretical analysis have been put in the computer code. Many optical beam elements are contained in the code. So, the code can simulate the intense dc particle motions in the beam transport lines, high voltage dc accelerators and ion implanters.

  13. 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...

  14. Precision control of intense electron beams in a low-energy ring

    Science.gov (United States)

    Wu, Chao

    Many applications of particle accelerators require beams with high intensity and low emittance in a stable fashion. An important research area involves the study of space-charge forces in beams, which are significant at low energy. Research reported in this dissertation was done on the University of Maryland Electron Ring (UMER), a particle accelerator designed for research on space-charge-dominated beams. High-precision control of space-charge-dominated beams is very challenging. However, standard beam control approaches do not work well on UMER. This is due to UMER's unique structure, in which there are fewer beam position monitors than beam position correctors and a complex coupling between the horizontal and vertical kicker magnets. In this work, a novel beam control algorithm was developed based on the closed-orbit response matrix, and this algorithm was applied to UMER. The algorithm markedly improves UMER's multi-turn operation while reducing closed orbit distortion. Using the orbit response matrix, a diagnosis method was developed that expeditiously detected malfunctions in components such as beam position monitors and magnets. Space-charge forces can greatly affect the resonant properties of rings. With the electrostatic particle-in-cell code WARP, ring resonances were analyzed under a variety of conditions. This resulted in an improved understanding of and capability to predict beam losses and improve machine performance. Simulation results using WARP were obtained for several magnet models and compared with results from other simulation codes. Experimental results on resonance analysis were also given using wall current monitor signals.

  15. On the way to high dynamic range beam profile measurements

    Energy Technology Data Exchange (ETDEWEB)

    Egberts, Jan; Artikova, Sayyora [Max-Planck-Institut fuer Kernphysik (Germany); Welsch, Carsten [University of Liverpool (United Kingdom); Cockcroft Institute of Accelerator Science and Technology (United Kingdom)

    2009-07-01

    A thorough understanding of halo formation and its possible control is highly desirable for essentially all particle accelerators. Particles outside the beam core are not only lost for further experiments, they are also likely to hit the drift chamber and thereby activate the beam pipe, which makes work on the accelerator costly and time consuming. A well-established technique for transverse beam profile measurements is synchrotron radiation (SR) for high energy and high luminosity accelerators like the LHC or CTF3. At much lower beam energies, an alternative for transverse beam profile measurements based on the direct measurement of light is optical transition radiation (OTR) or the insertion of a luminescent screen. What applies for essentially all these light generation processes, is that the light intensity is over a wide range proportional to the particle density, which makes the optical analysis of such light an ideal tool for beam profile measurements. A particular challenge, however, is to distinguish the particles in the tail regions of the beam distribution from the much more intense beam core. In this contribution, we present results from laboratory measurements on two different devices that might form the technical base of a future beam halo monitor: the novel SpectraCam XDR camera system and a flexible masking technique based on a DMD micro mirror array.

  16. Beam profile measurement on HITU transducers using a thermal intensity sensor technique

    Science.gov (United States)

    Wilkens, V.; Sonntag, S.; Jenderka, K.-V.

    2011-02-01

    Thermal intensity sensors based on the transformation of the incident ultrasonic energy into heat inside a small cylindrical absorber have been developed at PTB in the past, in particular to determine the acoustic output of medical diagnostic ultrasound equipment. Currently, this sensor technique is being expanded to match the measurement challenges of high intensity therapeutic ultrasound (HITU) fields. At the high acoustic power levels as utilized in the clinical application of HITU transducers, beam characterization using hydrophones is critical due to the possible damage of the sensitive and expensive measurement devices. Therefore, the low-cost and robust thermal sensors developed offer a promising alternative for the determination of high intensity output beam profiles. A sensor prototype with a spatial resolution of 0.5 mm was applied to the beam characterization of an HITU transducer operated at several driving amplitude levels. Axial beam plots and lateral profiles at focus were acquired. The absolute continuous wave output power was, in addition, determined using a radiation force balance.

  17. Studies of the Core Conditions of the Earth and Super-Earths Using Intense Ion Beams at FAIR

    Science.gov (United States)

    Tahir, N. A.; Lomonosov, I. V.; Borm, B.; Piriz, A. R.; Shutov, A.; Neumayer, P.; Bagnoud, V.; Piriz, S. A.

    2017-09-01

    Using detailed numerical simulations, we present the design of an experiment that will generate samples of iron under extreme conditions of density and pressure believed to exist in the interior of the Earth and interior of extrasolar Earth-like planets. In the proposed experiment design, an intense uranium beam is used to implode a multilayered cylindrical target that consists of a thin Fe cylinder enclosed in a thick massive W shell. Such intense uranium beams will be available at the heavy-ion synchrotron, SIS100, at the Facility for Antiprotons and Ion Research (FAIR), at Darmstadt, which is under construction and will become operational in the next few years. It is expected that the beam intensity will increase gradually over a couple of years to its maximum design value. Therefore, in our studies, we have considered a wide range of beam parameters, from the initial beam intensity (“Day One”) to the maximum specified value. It is also worth noting that two different focal spot geometries have been used. In one case, a circular focal spot with a Gaussian transverse intensity distribution is considered, whereas in the other case, an annular focal spot is used. With these two beam geometries, one can access different parts of the Fe phase diagram. For example, heating the sample with a circular focal spot generates a hot liquid state, while an annular focal spot can produce a highly compressed liquid or a highly compressed solid phase depending on the beam intensity.

  18. The effect of the dc bias voltage on the x-ray bremsstrahlung and beam intensities of medium and highly charged ions of argon.

    Science.gov (United States)

    Rodrigues, G; Lakshmy, P S; Baskaran, R; Kanjilal, D; Roy, A

    2010-02-01

    X-ray bremsstrahlung measurements from the 18 GHz High Temperature Superconducting Electron Cyclotron Resonance Ion Source, Pantechnik-Delhi Ion Source were measured as a function of negative dc bias voltage, keeping all other source operating parameters fixed and the extraction voltage in the off condition. The optimization of medium and highly charged ions of argon with similar source operating parameters is described. It is observed that the high temperature component of the electron is altered significantly with the help of bias voltage, and the electron population has to be maximized for obtaining higher current.

  19. Design of measurement equipment for high power laser beam shapes

    DEFF Research Database (Denmark)

    Hansen, K. S.; Olsen, F. O.; Kristiansen, Morten

    2013-01-01

    To analyse advanced high power beam patterns, a method, which is capable of analysing the intensity distribution in 3D is needed. Further a measuring of scattered light in the same system is preferred. This requires a high signal to noise ratio. Such a system can be realised by a CCD-chip impleme......To analyse advanced high power beam patterns, a method, which is capable of analysing the intensity distribution in 3D is needed. Further a measuring of scattered light in the same system is preferred. This requires a high signal to noise ratio. Such a system can be realised by a CCD...

  20. Diagnostics for ion beam driven high energy density physics experiments.

    Science.gov (United States)

    Bieniosek, F M; Henestroza, E; Lidia, S; Ni, P A

    2010-10-01

    Intense beams of heavy ions are capable of heating volumetric samples of matter to high energy density. Experiments are performed on the resulting warm dense matter (WDM) at the NDCX-I ion beam accelerator. The 0.3 MeV, 30 mA K(+) beam from NDCX-I heats foil targets by combined longitudinal and transverse neutralized drift compression of the ion beam. Both the compressed and uncompressed parts of the NDCX-I beam heat targets. The exotic state of matter (WDM) in these experiments requires specialized diagnostic techniques. We have developed a target chamber and fielded target diagnostics including a fast multichannel optical pyrometer, optical streak camera, laser Doppler-shift interferometer (Velocity Interferometer System for Any Reflector), beam transmission diagnostics, and high-speed gated cameras. We also present plans and opportunities for diagnostic development and a new target chamber for NDCX-II.

  1. Diagnostics for ion beam driven high energy density physics experimentsa)

    Science.gov (United States)

    Bieniosek, F. M.; Henestroza, E.; Lidia, S.; Ni, P. A.

    2010-10-01

    Intense beams of heavy ions are capable of heating volumetric samples of matter to high energy density. Experiments are performed on the resulting warm dense matter (WDM) at the NDCX-I ion beam accelerator. The 0.3 MeV, 30 mA K+ beam from NDCX-I heats foil targets by combined longitudinal and transverse neutralized drift compression of the ion beam. Both the compressed and uncompressed parts of the NDCX-I beam heat targets. The exotic state of matter (WDM) in these experiments requires specialized diagnostic techniques. We have developed a target chamber and fielded target diagnostics including a fast multichannel optical pyrometer, optical streak camera, laser Doppler-shift interferometer (Velocity Interferometer System for Any Reflector), beam transmission diagnostics, and high-speed gated cameras. We also present plans and opportunities for diagnostic development and a new target chamber for NDCX-II.

  2. Electron beam based transversal profile measurements of intense ion beams; Elektronenstrahl-Diagnostik zur Bestimmung vom transversalen Profil intensiver Ionenstrahlen

    Energy Technology Data Exchange (ETDEWEB)

    El Moussati, Said

    2014-11-03

    application range of the EBI diagnostic method and to benchmark the theoretical model. To achieve this goal a code has been developed in the programming language Python. Different charge distributions were considered and the simulation results have been compared with the theoretical model. The numerical investigations have shown a very good agreement with the theoretical model for deflection angles up to 20 mrad. This value defines the limit for the applicability of the theoretical model. Moreover, the magnetic field of the ion beam has also been taken into acount in the simulations. The results show that at high ion beam currents - starting at about 1 A - the electrons experience a non-negligible displacement along the ion beam axis, which has to be taken into consideration in experiments with intense heavy ion beams. The electrons suffer practically the same displacement under the influence of the magnetic field, regardless of their offset. At an offset of 10 mm the deviation from the shift at the ion beam axis is less than 3 %. For the experimental investigations of the EBI diagnostic method an offline experiment had been set up at the HHT experimental area at GSI in Darmstadt. The Coulomb field of the ion beam had been simulated by electrostatically charged wires. In case of a single wire, the experimental results are in good agreement with the theoretical model for deflection angles up to 20 mrad. This confirms the results of the numerical studies. To simulate the field within an ion beam, several wires have been clamped parallel to each other within a plane perpendicular to the electron beam. The electrons thus could pass through the spaces between the wires. The results of this experiments have quantitatively confirmed the prediction of the theoretical model that the derivative of the deflection angle with respect to the offset is proportional to the charge distribution in the cross section of the ion beam. Quantitatively, however, deviations from the theoretical model

  3. Intense laser-driven ion beams in the relativistic-transparency regime: acceleration, control and applications

    Science.gov (United States)

    Fernandez, Juan C.

    2016-10-01

    Laser-plasma interactions in the novel regime of relativistically-induced transparency have been harnessed to generate efficiently intense ion beams with average energies exceeding 10 MeV/nucleon (>100 MeV for protons) at ``table-top'' scales. We have discovered and utilized a self-organizing scheme that exploits persisting self-generated plasma electric ( 0.1 TV/m) and magnetic ( 104 Tesla) fields to reduce the ion-energy (Ei) spread after the laser exits the plasma, thus separating acceleration from spread reduction. In this way we routinely generate aluminum and carbon beams with narrow spectral peaks at Ei up to 310 MeV and 220 MeV, respectively, with high efficiency ( 5%). The experimental demonstration has been done at the LANL Trident laser with 0.12 PW, high-contrast, 0.65 ps Gaussian laser pulses irradiating planar foils up to 250 nm thick. In this regime, Ei scales empirically with laser intensity (I) as I 1 / 2. Our progress is enabled by high-fidelity, massive computer simulations of the experiments. This work advances next-generation compact accelerators suitable for new applications. E . g ., a carbon beam with Ei 400 MeV and 10% energy spread is suitable for fast ignition (FI) of compressed DT. The observed scaling suggests that is feasible with existing target fabrication and PW-laser technologies, using a sub-ps laser pulse with I 2.5 ×1021 W/cm2. These beams have been used on Trident to generate warm-dense matter at solid-densities, enabling us to investigate its equation of state and mixing of heterogeneous interfaces purely by plasma effects distinct from hydrodynamics. They also drive an intense neutron-beam source with great promise for important applications such as active interrogation of shielded nuclear materials. Considerations on controlling ion-beam divergence for their increased utility are discussed. Funded by the LANL LDRD program.

  4. Simulations and experiments of intense ion beam current density compression in space and timea)

    Science.gov (United States)

    Sefkow, A. B.; Davidson, R. C.; Gilson, E. P.; Kaganovich, I. D.; Anders, A.; Coleman, J. E.; Leitner, M.; Lidia, S. M.; Roy, P. K.; Seidl, P. A.; Waldron, W. L.; Yu, S. S.; Welch, D. R.

    2009-05-01

    The Heavy Ion Fusion Science Virtual National Laboratory has achieved 60-fold longitudinal pulse compression of ion beams on the Neutralized Drift Compression Experiment (NDCX) [P. K. Roy et al., Phys. Rev. Lett. 95, 234801 (2005)]. To focus a space-charge-dominated charge bunch to sufficiently high intensities for ion-beam-heated warm dense matter and inertial fusion energy studies, simultaneous transverse and longitudinal compression to a coincident focal plane is required. Optimizing the compression under the appropriate constraints can deliver higher intensity per unit length of accelerator to the target, thereby facilitating the creation of more compact and cost-effective ion beam drivers. The experiments utilized a drift region filled with high-density plasma in order to neutralize the space charge and current of an ˜300 keV K+ beam and have separately achieved transverse and longitudinal focusing to a radius 2 MeV) ion beam user-facility for warm dense matter and inertial fusion energy-relevant target physics experiments.

  5. Accessing Defect Dynamics using Intense, Nanosecond Pulsed Ion Beams

    Science.gov (United States)

    Persaud, A.; Barnard, J. J.; Guo, H.; Hosemann, P.; Lidia, S.; Minor, A. M.; Seidl, P. A.; Schenkel, T.

    Gaining in-situ access to relaxation dynamics of radiation induced defects will lead to a better understanding of materials and is important for the verification of theoretical models and simulations. We show preliminary results from experiments at the new Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory that will enable in-situ access to defect dynamics through pump-probe experiments. Here, the unique capabilities of the NDCX-II accelerator to generate intense, nanosecond pulsed ion beams are utilized. Preliminary data of channeling experiments using lithium and potassium ions and silicon membranes are shown. We compare these data to simulation results using Crystal Trim. Furthermore, we discuss the improvements to the accelerator to higher performance levels and the new diagnostics tools that are being incorporated.

  6. Forward acceleration and generation of femtosecond, megaelectronvolt electron beams by an ultrafast intense laser pulse

    Institute of Scientific and Technical Information of China (English)

    Xiaofang wang(王晓方); Quandong Wang(汪权东); Baifei Shen(沈百飞)

    2003-01-01

    We present a new mechanism of energy gain of electrons accelerated by a laser pulse. It is shown that when the intensity of an ultrafast intense laser pulse decreases rapidly along the direction of propagation, electrons leaving the pulse experience an action of ponderomotive deceleration at the descending part of a lower-intensity laser field than acceleration at the ascending part of a high-intensity field, thus gain net energy from the pulse and move directly forward. By means of such a mechanism, a megaelectronvolt electron beam with a bunch length shorter than 100 fs could be realized with an ultrafast (≤30 fs),intense (>1019 W/cm2) laser pulse.

  7. Infrared imaging diagnostics for intense pulsed electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiao; Shen, Jie; Liu, Wenbin; Zhong, Haowen; Zhang, Jie; Zhang, Gaolong; Le, Xiaoyun, E-mail: xyle@buaa.edu.cn [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); International Research Center for Nuclei and Particles in the Cosmos, Beihang University, Beijing 100191 (China); Qu, Miao; Yan, Sha [Institute of Heavy Ion Physics, Peking University, Beijing 100871 (China)

    2015-08-15

    Infrared imaging diagnostic method for two-dimensional calorimetric diagnostics has been developed for intense pulsed electron beam (IPEB). By using a 100-μm-thick tungsten film as the infrared heat sink for IPEB, the emitting uniformity of the electron source can be analyzed to evaluate the efficiency and stability of the diode system. Two-dimensional axisymmetric finite element method heat transfer simulation, combined with Monte Carlo calculation, was performed for error estimation and optimization of the method. The test of the method was finished with IPEB generated by explosive emission electron diode with pulse duration (FWHM) of 80 ns, electron energy up to 450 keV, and a total beam current of over 1 kA. The results showed that it is possible to measure the cross-sectional energy density distribution of IPEB with energy sensitivity of 0.1 J/cm{sup 2} and spatial resolution of 1 mm. The technical details, such as irradiation protection of bremsstrahlung γ photons and the functional extensibility of the method were discussed in this work.

  8. Infrared imaging diagnostics for intense pulsed electron beam.

    Science.gov (United States)

    Yu, Xiao; Shen, Jie; Qu, Miao; Liu, Wenbin; Zhong, Haowen; Zhang, Jie; Yan, Sha; Zhang, Gaolong; Le, Xiaoyun

    2015-08-01

    Infrared imaging diagnostic method for two-dimensional calorimetric diagnostics has been developed for intense pulsed electron beam (IPEB). By using a 100-μm-thick tungsten film as the infrared heat sink for IPEB, the emitting uniformity of the electron source can be analyzed to evaluate the efficiency and stability of the diode system. Two-dimensional axisymmetric finite element method heat transfer simulation, combined with Monte Carlo calculation, was performed for error estimation and optimization of the method. The test of the method was finished with IPEB generated by explosive emission electron diode with pulse duration (FWHM) of 80 ns, electron energy up to 450 keV, and a total beam current of over 1 kA. The results showed that it is possible to measure the cross-sectional energy density distribution of IPEB with energy sensitivity of 0.1 J/cm(2) and spatial resolution of 1 mm. The technical details, such as irradiation protection of bremsstrahlung γ photons and the functional extensibility of the method were discussed in this work.

  9. ELECTRON CLOUD EFFECTS IN HIGH INTENSITY PROTON ACCELERATORS.

    Energy Technology Data Exchange (ETDEWEB)

    WEI,J.; MACEK,R.J.

    2002-04-14

    One of the primary concerns in the design and operation of high-intensity proton synchrotrons and accumulators is the electron cloud and associated beam loss and instabilities. Electron-cloud effects are observed at high-intensity proton machines like the Los Alamos National Laboratory's PSR and CERN's SPS, and investigated experimentally and theoretically. In the design of next-generation high-intensity proton accelerators like the Spallation Neutron Source ring, emphasis is made in minimizing electron production and in enhancing Landau damping. This paper reviews the present understanding of the electron-cloud effects and presents mitigation measures.

  10. A Highly intense DC muon source, MuSIC and muon CLFV search

    Science.gov (United States)

    Hino, Y.; Kuno, Y.; Sato, A.; Sakamoto, H.; Matsumoto, Y.; Tran, N. H.; Hashim, I. H.; Fukuda, M.; Hayashida, Y.; Ogitsu, T.; Yamamoto, A.; Yoshida, M.

    2014-08-01

    MuSIC is a new muon facility, which provides the world's highest intense muon beam with continuous time structure at Research Center of Nuclear Physics (RCNP), Osaka University. It's intensity is designed to be 108 muons per second with only 0.4 kW proton beam. Such a high intense muon beam is very important for searches of rare decay processes, for example search for the muon to electron conversion.

  11. A Highly intense DC muon source, MuSIC and muon CLFV search

    Energy Technology Data Exchange (ETDEWEB)

    Hino, Y.; Kuno, Y.; Sato, A. [Department of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Sakamoto, H. [Department of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Research Center of Nuclear Physics, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Matsumoto, Y.; Tran, N.H.; Hashim, I.H. [Department of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Fukuda, M.; Hayashida, Y. [Research Center of Nuclear Physics, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Ogitsu, T.; Yamamoto, A.; Yoshida, M. [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2014-08-15

    MuSIC is a new muon facility, which provides the world's highest intense muon beam with continuous time structure at Research Center of Nuclear Physics (RCNP), Osaka University. It's intensity is designed to be 10{sup 8} muons per second with only 0.4 kW proton beam. Such a high intense muon beam is very important for searches of rare decay processes, for example search for the muon to electron conversion.

  12. Focused ion beams using a high-brightness plasma source

    Science.gov (United States)

    Guharay, Samar

    2002-10-01

    High-brightness ion beams, with low energy spread, have merits for many new applications in microelectronics, materials science, and biology. Negative ions are especially attractive for the applications that involve beam-solid interactions. When negative ions strike a surface, especially an electrically isolated surface, the surface charging voltage is limited to few volts [1]. This property can be effectively utilized to circumvent problems due to surface charging, such as device damage and beam defocusing. A compact plasma source, with the capability to deliver either positive or negative ion beams, has been developed. H- beams from this pulsed source showed brightness within an order of magnitude of the value for beams from liquid-metal ion sources. The beam angular intensity is > 40 mAsr-1 and the corresponding energy spread is 1 Acm-2 and a spot size of 100 nm. Such characteristics of focused beam parameters, using a dc source, will immediately open up a large area of new applications. [1] P. N. Guzdar, A. S. Sharma, S. K. Guharay, "Charging of substrates irradiated by particle beams" Appl. Phys. Lett. 71, 3302 (1997). [2] S. K. Guharay, E. Sokolovsky, J. Orloff, "Characteristics of ion beams from a Penning source for focused ion beam applications" J. Vac. Sci Technol. B17, 2779 (1999).

  13. Effects on structure and properties of Zr{sub 55}Al{sub 10}Cu{sub 30}Ni{sub 5} metallic glass irradiated by high intensity pulsed ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaofei [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian, 116024 (China); Mei, Xianxiu, E-mail: xxmei@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian, 116024 (China); Qiang, Jianbing [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian, 116024 (China); Remnev, G.E. [High Voltage Research Institute Tomsk Polytechnic University, Tomsk, 634028 (Russian Federation); Wang, Younian [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian, 116024 (China)

    2014-09-15

    Highlights: • HIPIB technology was used for the irradiation of metallic glass Zr-based and W. • Metallic glass remained amorphous in its main structure after HIPIB irradiation. • On metallic glass surface appeared nanocrystalline only at 300 times irradiation. • The nano-hardness of irradiated metallic glass surface was decreased. • Cracks appeared on the surface of W after HIPIB irradiation. - Abstract: High intensity pulsed ion beam technology was used for the surface irradiation treatment of metallic glass Zr{sub 55}Al{sub 10}Cu{sub 30}Ni{sub 5} and W metal. The ion beam was mainly composed of C{sup n+} (70%) and H{sup +} (30%) at an acceleration voltage of 250 kV under different energy densities for different number of pulses. XRD analysis showed that the metallic glass remained amorphous in its main structure after HIPIB irradiation, without apparent presence of crystalline phases. SEM analysis concluded that there was no apparent irradiation damage on the surface of metallic glass at the low irradiation frequency (3 times and 10 times); “petal”-shaped irradiation damage appeared on the surface of metallic glass after multi-irradiation (100 times and 300 times), and the composition of the petal center included Fe and Cr, the composition of an ion diode cathode, in addition to the composition of Zr-based metallic glass. TEM analysis of irradiated metallic glass showed that a small amount of nanocrystalline Zr{sub 2}Ni-type phase (face centered cubic) was produced only at 300-time irradiation. Cracks appeared on the surface of W after 100-time and 300-time irradiation; shedding phenomenon even appeared on the surface of W at the energy densities of 1.4 J/cm{sup 2} and 2.0 J/cm{sup 2}. The surface nano-hardness of irradiated metallic glass decreased.

  14. Vortex dynamics and shear layer instability in high intensity cyclotrons

    CERN Document Server

    Cerfon, Antoine J

    2016-01-01

    We show that the space charge dynamics of high intensity beams in the plane perpendicular to the magnetic field in cyclotrons is described by the two-dimensional Euler equations for an incompressible fluid. This analogy with fluid dynamics gives a unified and intuitive framework to explain the beam spiraling and beam break up behavior observed in experiments and in simulations. In particular, we demonstrate that beam break up is the result of a classical instability occurring in fluids subject to a sheared flow. We give scaling laws for the instability and predict the nonlinear evolution of beams subject to it. Our work suggests that cyclotrons may be uniquely suited for the experimental study of shear layers and vortex distributions that are not achievable in Penning-Malmberg traps.

  15. Average intensity and spreading of a Lorentz-Gauss beam in turbulent atmosphere.

    Science.gov (United States)

    Zhou, Guoquan; Chu, Xiuxiang

    2010-01-18

    The propagation of a Lorentz-Gauss beam in turbulent atmosphere is investigated. Based on the extended Huygens-Fresnel integral and the Hermite-Gaussian expansion of a Lorentz function, analytical formulae for the average intensity and the effective beam size of a Lorentz-Gauss beam are derived in turbulent atmosphere. The average intensity distribution and the spreading properties of a Lorentz-Gauss beam in turbulent atmosphere are numerically demonstrated. The influences of the beam parameters and the structure constant of the atmospheric turbulence on the propagation of a Lorentz-Gauss beam in turbulent atmosphere are also discussed in detail.

  16. Facility for parity and time reversal experiments with intense epithermal (eV) neutron beams

    Science.gov (United States)

    Bowman, C. D.; Bowman, J. D.; Herczeg, P.; Szymanski, J.; Yuan, V. W.; Anaya, J. M.; Mortensen, R.; Postma, H.; Delheij, P. P. J.; Baker, O. K.; Gould, C. R.; Haase, D. G.; Mitchell, G. E.; Roberson, N. R.; Zhu, X.; McDonald, A. B.; Benton, D.; Tippens, B.; Chupp, T. E.

    1988-12-01

    A facility for polarized epithermal neutrons of high intensity is set up at the Los Alamos National Laboratory for parityviolation and time reversal experiments at neutron resonances over a wide range of neutron energies. The beam is polarized with the aid of a polarized proton target used as a neutronspin filter. Total cross section measurements as well as capture gamma-ray experiments will be carried out. The main features of this system will be discussed.

  17. Annotated bibliography on high-intensity linear accelerators. [240 citations

    Energy Technology Data Exchange (ETDEWEB)

    Jameson, R.A.; Roybal, E.U.

    1978-01-01

    A technical bibliography covering subjects important to the design of high-intensity beam transport systems and linear accelerators is presented. Space charge and emittance growth are stressed. Subject and author concordances provide cross-reference to detailed citations, which include an abstract and notes on the material. The bibliography resides in a computer database that can be searched for key words and phrases.

  18. High Pressure, High Gradient RF Cavities for Muon Beam Cooling

    CERN Document Server

    Johnson, R P

    2004-01-01

    High intensity, low emittance muon beams are needed for new applications such as muon colliders and neutrino factories based on muon storage rings. Ionization cooling, where muon energy is lost in a low-Z absorber and only the longitudinal component is regenerated using RF cavities, is presently the only known cooling technique that is fast enough to be effective in the short muon lifetime. RF cavities filled with high-pressure hydrogen gas bring two advantages to the ionization technique: the energy absorption and energy regeneration happen simultaneously rather than sequentially, and higher RF gradients and better cavity breakdown behavior are possible than in vacuum due to the Paschen effect. These advantages and some disadvantages and risks will be discussed along with a description of the present and desired RF R&D efforts needed to make accelerators and colliders based on muon beams less futuristic.

  19. Definitive Reirradiation for Locoregionally Recurrent Non-Small Cell Lung Cancer With Proton Beam Therapy or Intensity Modulated Radiation Therapy: Predictors of High-Grade Toxicity and Survival Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    McAvoy, Sarah; Ciura, Katherine; Wei, Caimiao; Rineer, Justin; Liao, Zhongxing; Chang, Joe Y.; Palmer, Matthew B.; Cox, James D.; Komaki, Ritsuko; Gomez, Daniel R., E-mail: DGomez@mdanderson.org

    2014-11-15

    Purpose: Intrathoracic recurrence of non-small cell lung cancer (NSCLC) after initial treatment remains a dominant cause of death. We report our experience using proton beam therapy and intensity modulated radiation therapy for reirradiation in such cases, focusing on patterns of failure, criteria for patient selection, and predictors of toxicity. Methods and Materials: A total of 102 patients underwent reirradiation for intrathoracic recurrent NSCLC at a single institution. All doses were recalculated to an equivalent dose in 2-Gy fractions (EQD2). All patients had received radiation therapy for NSCLC (median initial dose of 70 EQD2 Gy), with median interval to reirradiation of 17 months and median reirradiation dose of 60.48 EQD2 Gy. Median follow-up time was 6.5 months (range, 0-72 months). Results: Ninety-nine patients (97%) completed reirradiation. Median local failure-free survival, distant metastasis-free survival (DMFS), and overall survival times were 11.43 months (range, 8.6-22.66 months), 11.43 months (range, 6.83-23.84 months), and 14.71 (range, 10.34-20.56 months), respectively. Toxicity was acceptable, with rates of grade ≥3 esophageal toxicity of 7% and grade ≥3 pulmonary toxicity of 10%. Of the patients who developed local failure after reirradiation, 88% had failure in either the original or the reirradiation field. Poor local control was associated with T4 disease, squamous histology, and Eastern Cooperative Oncology Group performance status score >1. Concurrent chemotherapy improved DMFS, but T4 disease was associated with poor DMFS. Higher T status, Eastern Cooperative Oncology Group performance status ≥1, squamous histology, and larger reirradiation target volumes led to worse overall survival; receipt of concurrent chemotherapy and higher EQD2 were associated with improved OS. Conclusions: Intensity modulated radiation therapy and proton beam therapy are options for treating recurrent non-small cell lung cancer. However, rates of

  20. Development of high current electron beam generator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byeong Cheol; Lee, Jong Min; Kim, Sun Kook [and others

    1997-05-01

    A high-current electron beam generator has been developed. The energy and the average current of the electron beam are 2 MeV and 50 mA, respectively. The electron beam generator is composed of an electron gun, RF acceleration cavities, a 260-kW RF generator, electron beam optics components, and control system, etc. The electron beam generator will be used for the development of a millimeter-wave free-electron laser and a high average power infrared free-electron laser. The machine will also be used as a user facility in nuclear industry, environment industry, semiconductor industry, chemical industry, etc. (author). 15 tabs., 85 figs.

  1. Axial electric wake field inside the induction gap exited by the intense electron beam

    Institute of Scientific and Technical Information of China (English)

    ZHANG Kai-Zhi; ZHANG Huang; LONG Ji-Dong; YANG Guo-Jun; HE Xiao-Zhong; WANG Hua-Cen

    2008-01-01

    While an intense electron beam passes through the accelerating gaps of a linear induction accelerator,a strong wake field will be excited.In this paper a relatively simple model is established based on the interaction between the transverse magnetic wake field and the electron beam,and the numerical calculation in succession generates a magnetic wake field distribution along the accelerator and along the beam pulse as well.The axial electric wake field is derived based on the relation between field components of a resonant mode.According to some principles in existence,the influence of this field on the high voltage properties of the induction gap is analyzed.The Dragon-I accelerator is taken as an example,and its maximum electric wake field is about 17 kV/cm,which means the effect of the wake field is noticeable.

  2. Longitudinal and transverse cooling of relativistic electron beams in intense laser pulses

    CERN Document Server

    Yoffe, Samuel R; Noble, Adam; Jaroszynski, Dino A

    2015-01-01

    With the emergence in the next few years of a new breed of high power laser facilities, it is becoming increasingly important to understand how interacting with intense laser pulses affects the bulk properties of a relativistic electron beam. A detailed analysis of the radiative cooling of electrons indicates that, classically, equal contributions to the phase space contraction occur in the transverse and longitudinal directions. In the weakly quantum regime, in addition to an overall reduction in beam cooling, this symmetry is broken, leading to significantly less cooling in the longitudinal than the transverse directions. By introducing an efficient new technique for studying the evolution of a particle distribution, we demonstrate the quantum reduction in beam cooling, and find that it depends on the distribution of energy in the laser pulse, rather than just the total energy as in the classical case.

  3. A high resolution hand-held focused beam profiler

    Science.gov (United States)

    Zapata-Farfan, J.; Garduño-Mejía, J.; Rosete-Aguilar, M.; Ascanio, G.; Román-Moreno, C. J.

    2017-05-01

    The shape of a beam is important in any laser application and depending on the final implementation, there exists a preferred one which is defined by the irradiance distribution.1 The energy distribution (or laser beam profile) is an important parameter in a focused beam, for instance, in laser cut industry, where the beam shape determines the quality of the cut. In terms of alignment and focusing, the energy distribution also plays an important role since the system must be configured in order to reduce the aberration effects and achieve the highest intensity. Nowadays a beam profiler is used in both industry and research laboratories with the aim to characterize laser beams used in free-space communications, focusing and welding, among other systems. The purpose of the profile analyzers is to know the main parameters of the beam, to control its characteristics as uniformity, shape and beam size as a guide to align the focusing system. In this work is presented a high resolution hand-held and compact design of a beam profiler capable to measure at the focal plane, with covered range from 400 nm to 1000 nm. The detection is reached with a CMOS sensor sized in 3673.6 μm x 2738.4 μm which acquire a snap shot of the previously attenuated focused beam to avoid the sensor damage, the result is an image of beam intensity distribution, which is digitally processed with a RaspberryTMmodule gathering significant parameters such as beam waist, centroid, uniformity and also some aberrations. The profiler resolution is 1.4 μm and was probed and validated in three different focusing systems. The spot sizes measurements were compared with the Foucault knife-edge test.

  4. Electron beam based transversal profile measurements of intense ion beams; Elektronenstrahl-Diagnostik zur Bestimmung vom transversalen Profil intensiver Ionenstrahlen

    Energy Technology Data Exchange (ETDEWEB)

    El Moussati, Said

    2014-11-03

    application range of the EBI diagnostic method and to benchmark the theoretical model. To achieve this goal a code has been developed in the programming language Python. Different charge distributions were considered and the simulation results have been compared with the theoretical model. The numerical investigations have shown a very good agreement with the theoretical model for deflection angles up to 20 mrad. This value defines the limit for the applicability of the theoretical model. Moreover, the magnetic field of the ion beam has also been taken into acount in the simulations. The results show that at high ion beam currents - starting at about 1 A - the electrons experience a non-negligible displacement along the ion beam axis, which has to be taken into consideration in experiments with intense heavy ion beams. The electrons suffer practically the same displacement under the influence of the magnetic field, regardless of their offset. At an offset of 10 mm the deviation from the shift at the ion beam axis is less than 3 %. For the experimental investigations of the EBI diagnostic method an offline experiment had been set up at the HHT experimental area at GSI in Darmstadt. The Coulomb field of the ion beam had been simulated by electrostatically charged wires. In case of a single wire, the experimental results are in good agreement with the theoretical model for deflection angles up to 20 mrad. This confirms the results of the numerical studies. To simulate the field within an ion beam, several wires have been clamped parallel to each other within a plane perpendicular to the electron beam. The electrons thus could pass through the spaces between the wires. The results of this experiments have quantitatively confirmed the prediction of the theoretical model that the derivative of the deflection angle with respect to the offset is proportional to the charge distribution in the cross section of the ion beam. Quantitatively, however, deviations from the theoretical model

  5. Generation of Intense High-Order Vortex Harmonics

    CERN Document Server

    Zhang, Xiaomei; Shi, Yin; Wang, Xiaofeng; Zhang, Lingang; Wang, Wenpeng; Xu, Jiancai; Yi, Longqiong; Xu, Zhizhan

    2014-01-01

    This paper presents the method for the first time to generate intense high-order optical vortices that carry orbital angular momentum in the extreme ultraviolet region. In three-dimensional particle-in-cell simulation, both the reflected and transmitted light beams include high-order harmonics of the Laguerre-Gaussian (LG) mode when a linearly polarized LG laser pulse impinges on a solid foil. The mode of the generated LG harmonic scales with its order, in good agreement with our theoretical analysis. The intensity of the generated high-order vortex harmonics is close to the relativistic region, and the pulse duration can be in attosecond scale. The obtained intense vortex beam possesses the combined properties of fine transversal structure due to the high-order mode and the fine longitudinal structure due to the short wavelength of the high-order harmonics. Thus, the obtained intense vortex beam may have extraordinarily promising applications for high-capacity quantum information and for high-resolution dete...

  6. Use of Intense Ion Beams for Surface Modification and Creation of New Materials

    CERN Document Server

    Renk, T; Prasad, S V; Provencio, P P; Thompson, M

    2002-01-01

    We have conducted surface treatment and alloying experiments with Al, Fe, and Ti-based metals on the RHEPP-1 accelerator (0.8 MV, 20 W, 80 ns FHWM, up to 1 Hz repetition rate) at Sandia National Laboratories. Ions are generated by the MAP gas-breakdown active anode, which can yield a number of different beam species including H, N, and C, depending upon the injected gas. Beams of intense pulsed high-power ion beams have been used to produce surface modification by changes in microstructure caused by rapid heating and cooling of the surface. Increase of beam power leads to ablation of a target surface, and redeposition of ablated material onto a separate substrate. Experiments are described in which ion beams are used in an attempt to increase high-voltage breakdown of a treated surface. Surface alloying of coated Pt and Hf layers is also described. This mixing of a previously deposited thin-film layer into a Ti-alloy substrate leads to significantly enhanced surface wear durability, compared to either untreat...

  7. A Highly Adjustable Helical Beam: Design and Propagation Characteristic

    CERN Document Server

    Wen, Yuanhui; Yu, Siyuan

    2016-01-01

    Light fields with extraordinary propagation behaviours such as nondiffracting and self-bending are useful in optical delivery for energy, information, and even objects. A kind of helical beams is constructed here based on the caustic method. With appropriate design, the main lobe of these helical beams can be both well-confined and almost nondiffracting while moving along a helix with its radius, period, the number of rotations and main lobes highly adjustable. In addition, the main lobe contains almost half of the optical power and the peak intensity fluctuates below 15% during propagation. These promising characteristics may enable a variety of potential applications based on these beams.

  8. Beam divergence effects on high power optical parametric oscillation

    Institute of Scientific and Technical Information of China (English)

    Li Hui-Qing; Geng Ai-Cong; Bo Yong; Wu Ling-An; Cui Da-Fu; Xu Zu-Yan

    2005-01-01

    The beam divergence effects of the input pump laser on a high power nanosecond optical parametric oscillator (OPO) have been numerically simulated. The OPO conversion efficiency is affected due to the angular deviation of real laser beams from ideal phase matching conditions. Our theoretical model is based on the decomposition of the Gaussian beam and assumes each component has a single deviation angle and thus a Particular wave vector mismatch. We take into account the variable intensity profile in the spatial and temporal domains of the Gaussian beam, the pump depletion effects for large-signal processes as well as the oscillatory effects of the three waves. Two nonlinear crystals β-BaB2O4 (BBO) and LiB3O5 (LBO) have been investigated in detail. The results indicate that the degree of beam divergence strongly influences the maximum pump intensity, optimum crystal length and OPO conversion efficiency.The impact of beam divergence is much more severe in the case of critical phase-matching for BBO than in the case of non-critical phase-matching for LBO. The results provide a way to choose the optimum parameters for a high power ns OPO such as the nonlinear material, the crystal length and the pump intensity, etc. Good agreement is obtained with our experimental results.

  9. The High Luminosity Challenge: potential and limitations of High Intensity High Brightness in the LHC and its injectors

    CERN Document Server

    De Maria, R; Banfi, D; Barranco, J; Bartosik, H; Benedetto, E; Bruce, R; Brüning, O; Calaga, R; Cerutti, F; Damerau, H; Esposito, L; Fartoukh, S; Fitterer, M; Garoby, R; Gilardoni, S; Giovannozzi, M; Goddard, B; Gorini, B; Hanke, K; Iadarola, G; Lamont, M; Meddahi, M; Métral, E; Mikulec, B; Mounet, N; Papaphilippou, Y; Pieloni, T; Redaelli, S; Rossi, L; Rumolo, G; Shaposhnikova, E; Sterbini, G; Todesco, E; Tomás, R; Zimmermann, F; Valishev, A

    2014-01-01

    High-intensity and high-brightness beams are key ingredients to maximize the LHC integrated luminosity and to exploit its full potential. This contribution describes the optimization of beam and machine parameters to maximize the integrated luminosity as seen by the LHC experiments, by taking into account the expected intensity and brightness reach of LHC itself and its injector chain as well as the capabilities of the detectors for next run and foreseen upgrade scenarios.

  10. First test of BNL electron beam ion source with high current density electron beam

    Science.gov (United States)

    Pikin, Alexander; Alessi, James G.; Beebe, Edward N.; Shornikov, Andrey; Mertzig, Robert; Wenander, Fredrik; Scrivens, Richard

    2015-01-01

    A new electron gun with electrostatic compression has been installed at the Electron Beam Ion Source (EBIS) Test Stand at BNL. This is a collaborative effort by BNL and CERN teams with a common goal to study an EBIS with electron beam current up to 10 A, current density up to 10,000 A/cm2 and energy more than 50 keV. Intensive and pure beams of heavy highly charged ions with mass-to-charge ratio heavy ion research facilities including NASA Space Radiation Laboratory (NSRL) at BNL and HIE-ISOLDE at CERN. With a multiampere electron gun, the EBIS should be capable of delivering highly charged ions for both RHIC facility applications at BNL and for ISOLDE experiments at CERN. Details of the electron gun simulations and design, and the Test EBIS electrostatic and magnetostatic structures with the new electron gun are presented. The experimental results of the electron beam transmission are given.

  11. Effect of electron cyclotron resonance ion source frequency tuning on ion beam intensity and quality at Department of Physics, University of Jyvaeskylae

    Energy Technology Data Exchange (ETDEWEB)

    Toivanen, V.; Koivisto, H.; Steczkiewicz, O.; Tarvainen, O.; Ropponen, T. [Department of Physics, University of Jyvaeskylae (JYFL) (Finland); Celona, L.; Gammino, S.; Mascali, D.; Ciavola, G. [Instituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, 95123 Catania (Italy)

    2010-02-15

    Ion beam intensity and quality have a crucial effect on the operation efficiency of the accelerator facilities. This paper presents the investigations on the ion beam intensity and quality after the mass separation performed with the Department of Physics, University of Jyvaeskylae 14 GHz electron cyclotron resonance ion source by sweeping the microwave in the 14.05-14.13 GHz range. In many cases a clear variation in the ion beam intensity and quality as a function of the frequency was observed. The effect of frequency tuning increased with the charge state. In addition, clear changes in the beam structure seen with the beam viewer were observed. The results confirmed that frequency tuning can have a remarkable effect on ion beam intensity and quality especially in the case of highly charged ion beams. The examples presented here represent the typical charge state behavior observed during the measurements.

  12. Non-destructive profile measurement of intensive heavy ion beams; Zerstoerungsfreie Profilmessung intensiver Schwerionenstrahlen

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Frank

    2010-02-08

    Within the framework of the FAIR-project (Facility for Antiproton and Ion Research) at GSI (Helmholtz Center for Heavy Ion Research), high intensity beams from protons to uranium ions with kinetic energies up to 30 AGeV are foreseen. Present GSI-accelerators like the UNILAC and the Heavy Ion Synchrotron (SIS-18) with a magnetic rigidity of 18 Tm will be used as injectors for the future synchrotron (SIS-100). Their beam current will be increased by up to two orders of magnitude. An accurate beam position and beam profile measurement is mandatory for a safe operation of transport sections, in particular in front of production targets (Fragment Separator (FRS)-target, anti p-production-target and Warm Dense Matter (WDM)-targets). Conventional intercepting profile monitors will not withstand the thermal stress of intensive ion beams, particularly for low energy applications or focused beams. For transverse profile determination a non-intercepting Beam Induced Fluorescence (BIF)-monitor was developed, working with residual gas. The BIF-monitor exploits fluorescence light emitted by residual gas molecules after atomic collisions with beam ions. Fluorescence-images were recorded with an image-intensified camera system, and beam profiles were obtained by projecting these images. Within the scope of this dissertation the following topics have been investigated: The photon yield, profile shape and background contribution were determined for different ion species (H{sup +}, S{sup 6+}, Ar{sup 18+}, K{sup +}, Ni{sup 9+}, Xe{sup 48+}, Ta{sup 24+}, Au{sup 65+}, U{sup 73+}), beam energies (7.7 AkeV-750 AMeV), gas pressures (10{sup -6}-3 mbar) and gas species (N{sub 2}, He, Ne, Ar, Kr, Xe). Applying an imaging spectrograph and narrowband 10 nm interference filters, the spectral response was mapped and associated with the corresponding gas transitions. Spectrally resolved beam profiles were also obtained form the spectrographic images. Major results are the light yield showing a

  13. Measurement of the transverse four-dimensional beam rms-emittance of an intense uranium beam at 11.4 MeV/u

    Science.gov (United States)

    Xiao, C.; Groening, L.; Gerhard, P.; Maier, M.; Mickat, S.; Vormann, H.

    2016-06-01

    Knowledge of the transverse four-dimensional beam rms-parameters is essential for applications that involve lattice elements that couple the two transverse degrees of freedom (planes). Usually pepper-pots are used for measuring these beam parameters. However, for ions their application is limited to energies below 150 keV/u. This contribution is on measurements of the full transverse four-dimensional second-moments beam matrix of high intensity uranium ions at an energy of 11.4 MeV/u. The combination of skew quadrupoles with a slit/grid emittance measurement device has been successfully applied.

  14. Beam Loss Calibration Studies for High Energy Proton Accelerators

    CERN Document Server

    Stockner, M

    2007-01-01

    CERN's Large Hadron Collider (LHC) is a proton collider with injection energy of 450 GeV and collision energy of 7 TeV. Superconducting magnets keep the particles circulating in two counter rotating beams, which cross each other at the Interaction Points (IP). Those complex magnets have been designed to contain both beams in one yoke within a cryostat. An unprecedented amount of energy will be stored in the circulating beams and in the magnet system. The LHC outperforms other existing accelerators in its maximum beam energy by a factor of 7 and in its beam intensity by a factor of 23. Even a loss of a small fraction of the beam particles may cause the transition from the superconducting to the normal conducting state of the coil or cause physical damage to machine components. The unique combination of these extreme beam parameters and the highly advanced superconducting technology has the consequence that the LHC needs a more efficient beam cleaning and beam loss measurement system than previous accelerators....

  15. Beam Loss Calibration Studies for High Energy Proton Accelerators

    CERN Document Server

    Stockner, M

    2007-01-01

    CERN's Large Hadron Collider (LHC) is a proton collider with injection energy of 450 GeV and collision energy of 7 TeV. Superconducting magnets keep the particles circulating in two counter rotating beams, which cross each other at the Interaction Points (IP). Those complex magnets have been designed to contain both beams in one yoke within a cryostat. An unprecedented amount of energy will be stored in the circulating beams and in the magnet system. The LHC outperforms other existing accelerators in its maximum beam energy by a factor of 7 and in its beam intensity by a factor of 23. Even a loss of a small fraction of the beam particles may cause the transition from the superconducting to the normal conducting state of the coil or cause physical damage to machine components. The unique combination of these extreme beam parameters and the highly advanced superconducting technology has the consequence that the LHC needs a more efficient beam cleaning and beam loss measurement system than previous accelerators....

  16. Average intensity and directionality of partially coherent model beams propagating in turbulent ocean.

    Science.gov (United States)

    Wu, Yuqian; Zhang, Yixin; Zhu, Yun

    2016-08-01

    We studied Gaussian beams with three different partially coherent models, including the Gaussian-Schell model (GSM), Laguerre-Gaussian Schell model (LGSM), and Bessel-Gaussian Schell model (BGSM), propagating through oceanic turbulence. The expressions of average intensity, beam spreading, and beam wander for GSM, LGSM, and BGSM beams in the paraxial channel are derived. We make a contrast for the three models in numerical simulations and find that the GSM beam has smaller spreading than the others, and the LGSM beam needs longer propagation distance to transform into a well-like profile of average intensity than the BGSM beam in the same conditions. The salinity fluctuation has a greater contribution to the wander of LGSM and BGSM beams than that of the temperature fluctuation. Our results can be helpful in the design of an optical wireless communication link operating in oceanic environment.

  17. Nonlinear Stability of Intense Mismatched Beams in a Uniform Focusing Field

    CERN Document Server

    Pakter, Renato; Simeoni, Wilson

    2005-01-01

    We investigate the nonlinear coupling between axisymmetric and elliptic oscillations in the dynamics of intense beams propagating in a uniform magnetic focusing field. It is shown that finite amplitude mismatched oscillations of an initially round beam may destabilize elliptic oscillations, heavily affecting stability and the shape of the beam. This is a potential mechanics for beam particle loss in such systems. Self consistent simulations are performed to verify the findings.

  18. Effect of turbulent atmosphere on the on-axis average intensity of Pearcey-Gaussian beam

    Science.gov (United States)

    F, Boufalah; L, Dalil-Essakali; H, Nebdi; A, Belafhal

    2016-06-01

    The propagation characteristics of the Pearcey-Gaussian (PG) beam in turbulent atmosphere are investigated in this paper. The Pearcey beam is a new kind of paraxial beam, based on the Pearcey function of catastrophe theory, which describes diffraction about a cusp caustic. By using the extended Huygens-Fresnel integral formula in the paraxial approximation and the Rytov theory, an analytical expression of axial intensity for the considered beam family is derived. Some numerical results for PG beam propagating in atmospheric turbulence are given by studying the influences of some factors, including incident beam parameters and turbulence strengths.

  19. Thermo-mechanical modelling of high energy particle beam impacts

    CERN Document Server

    Scapin, M; Dallocchio, A

    2010-01-01

    The unprecedented energy intensities of modern hadron accelerators yield special problems with the materials that are placed close to or into the high intensity beams. The energy stored in LHC in a single beam is equivalent to about 80 kg of TNT explosive, stored in a transverse beam area of 0.2 mm×0.2 mm. The materials placed close to the beam are used at, or even beyond, their damage limits. However, it is very difficult to predict structural efficiency and robustness accurately: beam-induced damage occurs in a regime where practical experience does not exist. This study is performed in order to estimate the damage on a copper component due to the impact with a 7 TeV proton beam generated by LHC. The case study represents an accidental case consequent to an abnormal release of the beam, in which 8 bunches irradiate the target directly. The energy delivered on the component is calculated using the FLUKA code and then used as input in the numerical simulations, that are carried out via the FEM code LS-DYNA. ...

  20. Predictors of High-grade Esophagitis After Definitive Three-dimensional Conformal Therapy, Intensity-modulated Radiation Therapy, or Proton Beam Therapy for Non-small cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Daniel R., E-mail: dgomez@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Tucker, Susan L. [Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Martel, Mary K.; Mohan, Radhe; Balter, Peter A. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Lopez Guerra, Jose Luis [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Radiation Oncology, Hospitales Universitarios Virgen del Rocio, Seville (Spain); Liu Hongmei; Komaki, Ritsuko; Cox, James D.; Liao Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2012-11-15

    Introduction: We analyzed the ability of various patient- and treatment-related factors to predict radiation-induced esophagitis (RE) in patients with non-small cell lung cancer (NSCLC) treated with three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), or proton beam therapy (PBT). Methods and Materials: Patients were treated for NSCLC with 3D-CRT, IMRT, or PBT at MD Anderson from 2000 to 2008 and had full dose-volume histogram (DVH) data available. The endpoint was severe (grade {>=}3) RE. The Lyman-Kutcher-Burman (LKB) model was used to analyze RE as a function of the fractional esophageal DVH, with clinical variables included as dose-modifying factors. Results: Overall, 652 patients were included: 405 patients were treated with 3D-CRT, 139 with IMRT, and 108 with PBT; corresponding rates of grade {>=}3 RE were 8%, 28%, and 6%, respectively, with a median time to onset of 42 days (range, 11-93 days). A fit of the fractional DVH LKB model demonstrated that the fractional effective dose was significantly different (P=.046) than 1 (fractional mean dose) indicating that high doses to small volumes are more predictive than mean esophageal dose. The model fit was better for 3D-CRT and PBT than for IMRT. Including receipt of concurrent chemotherapy as a dose-modifying factor significantly improved the LKB model (P=.005), and the model was further improved by including a variable representing treatment with >30 fractions. Examining individual types of chemotherapy agents revealed a trend toward receipt of concurrent taxanes and increased risk of RE (P=.105). Conclusions: Fractional dose (dose rate) and number of fractions (total dose) distinctly affect the risk of severe RE, estimated using the LKB model, and concurrent chemotherapy improves the model fit. This risk of severe RE is underestimated by this model in patients receiving IMRT.

  1. Observations and diagnostics in high brightness beams

    Energy Technology Data Exchange (ETDEWEB)

    Cianchi, A., E-mail: alessandro.cianchi@roma2.infn.it [University of Rome Tor Vergata and INFN-Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome (Italy); Anania, M.P.; Bisesto, F.; Castellano, M.; Chiadroni, E.; Pompili, R.; Shpakov, V. [INFN-LNF, Via Enrico Fermi 40, 00044 Frascati (Italy)

    2016-09-01

    The brightness is a figure of merit largely used in the light sources, like FEL (Free Electron Lasers), but it is also fundamental in several other applications, as for instance Compton backscattering sources, beam driven plasma accelerators and THz sources. Advanced diagnostics are essential tools in the development of high brightness beams. 6D electron beam diagnostics will be reviewed with emphasis on emittance measurement.

  2. Self-consistent Vlasov-Maxwell description of the longitudinal dynamics of intense charged particle beams

    Directory of Open Access Journals (Sweden)

    Ronald C. Davidson

    2004-02-01

    Full Text Available This paper describes a self-consistent kinetic model for the longitudinal dynamics of a long, coasting beam propagating in straight (linear geometry in the z direction in the smooth-focusing approximation. Starting with the three-dimensional Vlasov-Maxwell equations, and integrating over the phase-space (x_{⊥},p_{⊥} transverse to beam propagation, a closed system of equations is obtained for the nonlinear evolution of the longitudinal distribution function F_{b}(z,p_{z},t and average axial electric field ⟨E_{z}^{s}⟩(z,t. The primary assumptions in the present analysis are that the dependence on axial momentum p_{z} of the distribution function f_{b}(x,p,t is factorable, and that the transverse beam dynamics remains relatively quiescent (absence of transverse instability or beam mismatch. The analysis is carried out correct to order k_{z}^{2}r_{w}^{2} assuming slow axial spatial variations with k_{z}^{2}r_{w}^{2}≪1, where k_{z}∼∂/∂z is the inverse length scale of axial variation in the line density λ_{b}(z,t=∫dp_{z}F_{b}(z,p_{z},t, and r_{w} is the radius of the conducting wall (assumed perfectly conducting. A closed expression for the average longitudinal electric field ⟨E_{z}^{s}⟩(z,t in terms of geometric factors, the line density λ_{b}, and its derivatives ∂λ_{b}/∂z,… is obtained for the class of bell-shaped density profiles n_{b}(r,z,t=(λ_{b}/πr_{b}^{2}f(r/r_{b}, where the shape function f(r/r_{b} has the form specified by f(r/r_{b}=(n+1(1-r^{2}/r_{b}^{2}^{n} for 0≤rbeam intensities (proportional to λ_{b} ranging from low-intensity, emittance-dominated beams, to very-high-intensity, low-emittance beams.

  3. Determination of Beam Intensity and Position in a Particle Accelerator

    CERN Document Server

    Kasprowicz, Grzegorz; Raich, Uli

    2011-10-04

    A subject of the thesis is conception, design, implementation, tests and deployment of new position measurement system of particle bunch in the CERN PS circular accelerator. The system is based on novel algorithms of particle position determination. The Proton Synchrotron accelerator (PS), installed at CERN†, although commissioned in 1959, still plays a central role in the production of beams for the Antiproton Decelerator, Super Proton Synchrotron, various experimental areas and for the Large Hadron Collider (LHC)‡. The PS produces beams of different types of particles, mainly protons, but also various species of ions. Almost all these particle beams pass through the PS. The quality of the beams delivered to the LHC has a direct impact on the effective luminosity, and therefore the performance of the instrumentation of the PS is of great importance. The old trajectory and orbit measurement system of the PS is dated back to 1988 and no longer fulfilled present day requirements. It used 40 beam posi...

  4. Determination of beam intensity and position in a particle accelerator

    CERN Document Server

    Kasprowicz, G

    2011-01-01

    A subject of the thesis is conception, design, implementation, tests and deployment of new position measurement system of particle bunch in the CERN PS circular accelerator. The system is based on novel algorithms of particle position determination. The Proton Synchrotron accelerator (PS), installed at CERN, although commissioned in 1959, still plays a central role in the production of beams for the Antiproton Decelerator, Super Proton Synchrotron, various experimental areas and for the Large Hadron Collider (LHC). The PS produces beams of different types of particles, mainly protons, but also various species of ions. Almost all these particle beams pass through the PS. The quality of the beams delivered to the LHC has a direct impact on the effective luminosity, and therefore the performance of the instrumentation of the PS is of great importance. The old trajectory and orbit measurement system of the PS is dated back to 1988 and no longer fulfilled present day requirements. It used 40 beam position monitors...

  5. High-brightness ultra-cold metastable neon-beam

    CERN Document Server

    Shimizu, Fujio

    2015-01-01

    This paper presents detailed characteristics of an ultra-cold bright metastable neon atomic beam which we have been using for atom-interferometric applications. The basis of the device is an atomic beam released from a magneto-optical trap (MOT) which is operated with a high intensity trapping laser, high magnetic quadrupole field, and large laser detuining. Mainly due to the complex structure of three dimensional magnetic field and laser beams, a bright small spot of atoms is formed near the center of the quadrupole magnetic field under an appropriate operating condition. We obtained the minimum trap diameter of 50 micron meter, the atomic density nearly 10^{13}cm^{-3}, and the atomic temperature slightly less than the Doppler limited temperature of 200 micro-K. By releasing trapped atoms we obtained an bright cold atomic beam which is not far from the collision limited atomic density.

  6. Output beam analysis of high power COIL

    Institute of Scientific and Technical Information of China (English)

    Deli Yu(于德利); Fengting Sang(桑凤亭); Yuqi Jin(金玉奇); Yizhu Sun(孙以珠)

    2003-01-01

    As the output power of a chemical oxygen iodine laser (COIL) increases, the output laser beam instabilityappears as the far-field beam spot drift and deformation for the large Fresnel number unstable resonator.In order to interpret this phenomenon, an output beam mode simulation code was developed with the fastFourier transform method. The calculation results show that the presence of the nonuniform gain in COILproduces a skewed output intensity distribution, which causes the mirror tilt and bulge due to the thermalexpansion. With the output power of COIL increases, the mirror surfaces, especially the back surface ofthe scraper mirror, absorb more and more heat, which causes the drift and deformation of far field beamspot seriously. The initial misalignment direction is an important factor for the far field beam spot driftingand deformation.

  7. High energy laser beam dump

    Science.gov (United States)

    Halpin, John

    2004-09-14

    The laser beam dump is positioned in a housing. An absorbing glass plate means is operatively connected to the housing. A heat sync means for extracting heat from the absorbing glass plate means is operatively connected to the housing and operatively connected to the absorbing glass plate means.

  8. Intense Atomic and Molecular Beams via Neon Buffer Gas Cooling

    CERN Document Server

    Patterson, David; Doyle, John M

    2008-01-01

    We realize a continuous guided beam of cold deuterated ammonia with a flux of 3e11 ND3 molecules/s and a continuous free-space beam of cold potassium with a flux of 1e16 K atoms/s. A novel feature of the buffer gas source used to produce these beams is cold neon, which, due to intermediate Knudsen number beam dynamics, produces a forward velocity and low-energy tail that is comparable to much colder helium-based sources. We expect this source to be trivially generalizable to a very wide range of atomic and molecular species with significant vapor pressure below 1000 K. This source has properties that make it a good starting point for laser cooling of molecules or atoms, cold collision studies, trapping, or nonlinear optics in buffer-gas-cooled atomic or molecular gases.

  9. The effects of transverse plasma flow on laser beam deflection and of ultra-intense laser beam filamentation on channel formation

    Science.gov (United States)

    Hinkel, D. E.

    1997-11-01

    Recent experiments conducted at Lawrence Livermore National Laboratory (LLNL) with the Nova and Janus lasers demonstrate deflection of the laser beam in plasma with flow transverse to the beam. In gas-filled hohlraum experiments(S. G. Glendinning et al.), the laser spot on the hohlraum wall is ~ 100 μm closer to the laser entrance hole (LEH) than in empty hohlraum experiments, which degrades drive symmetry. In a series of exploding foil experiments(J. D. Moody et al.), Phys. Rev. Lett. 77, 1294 (1996)., intensity dependent deflection of the transmitted beam is observed, and interferometric measurements of laser-produced channels in preformed plasma(P. E. Young et al.), to be submitted to Phys. Rev. Lett., 1997. show beam deflection in the presence of near-sonic transverse flow. Theoretical analysis(D. E. Hinkel et al.), Phys. Rev. Lett. 77, 1298 (1996). yields simple scaling laws for the formation of ponderomotively (or thermally) created density depressions downstream from the laser beam's high intensity regions, into which the light is refracted. An integrated approach that utilizes plasma parameters from the hydrocode Lasnex, detailed knowledge of the beam structure, and plasma physics analysis and modelling with F3D(R. L. Berger et al.), Phys. Fluids B 5, 2243 (1993)., has been used to develop a predictive capability that successfully quantifies the amount of beam deflection occurring in experiments. Related physics of beam self-focussing and filamentation is of relevance to the Fast Ignitor(M. Tabak et al.), Phys. Plasmas 1, 1626 (1994).. In channeling experiments performed on the 100 TW laser at LLNL, the f/3 laser beam, which has a 15 μm waist at best focus, has intensities in excess of IL = 1 × 10^17 W/cm^2. Modelling of these high intensity experiments indicates that channel formation occurs over a wide range of cone angles for an idealized (Gaussian) beam. However, when beam structure is taken into consideration, channel formation in the underdense

  10. Controlling fast electron beam divergence via temporal shaping of the laser intensity envelope

    CERN Document Server

    Scott, R H H; Beaucourt, C; Markey, K; Lancaster, K L; Brenner, C M; Gray, R J; Musgrave, I O; Robinson, A P L; Li, K; Pasley, J; Notley, M M; Davies, J R; Baton, S D; Santos, J J; McKenna, P; Neely, D; Rose, S J; Norreys, P A

    2010-01-01

    A new experimental technique is described which uses two relativistically intense laser pulses to control and enhance the properties of the MeV electron beam generated during the interaction of an ultra-high-intensity laser pulse with a solid target. Both thermal and Cu K$_{\\alpha}$ x-ray imaging diagnostics show reduced emission size, increased peak emission, increased total emission, and reduced shot-to-shot variability with respect to a single high-contrast pulse. This evidences reduced fast electron divergence, increased fast electron current density and increased energy absorption into the target via fast electrons. The observed characteristics are attributed to magnetic field generation within the target and alterations to the plasma density scale length.

  11. 强流电子束入射叠靶能量沉积计算%Simulation on distributed target material impacted by high intensity current multi-pulse electron beam

    Institute of Scientific and Technical Information of China (English)

    胡林; 雷奕安; 朱隽

    2013-01-01

    The bremsstrahlung and energy deposition of multi-pulse high intensity relativistic electron beam injecting into multi-layer tantalum-graphite target are investigated.The energy deposition is calculated by Geant4 code,and the bremsstrahlung by fundamental radiation theory and Monte-Carlo method.The calculated results show the energy deposition in the hotspot of each layer decreases.The emittance and the radial distribution of the bremsstrahlung and electron beam are mostly affected by the tantalum layers.The low energy deposition rate and high heat capacity of graphite layers can improve the thermodynamic properties of the target.For a single pulse,at the tantalum-graphite thickness ratio 1 ∶ 1,the graphite can absorb all heat deposition of the neighboring tantalum layers,and the bremsstrahlung efficiency is 35.4 %.With 4 pulses,the ratio should be 1 ∶ 13,and the total bremsstrahlung efficiency decreases to 19.9 %.Considering the requirement of bremsstrahlung X-ray quantity and quality,the total thickness of tantalum should be 1.2 mm if the Ta-C thickness ratio is 1 ∶ 5,and 0.7 mm if the ratio is 1 ∶ 10.%计算了多脉冲相对论强流电子束入射钽-石墨叠靶的能量沉积和轫致辐射谱.能量沉积采用Geant4程序计算,轫致辐射谱根据基本的辐射理论和蒙特卡罗方法计算.结果显示,各层的热区能量沉积呈由大到小的递减分布,截面轫致辐射分布和电子束径向分布主要受钽层的影响.石墨层的低能量沉积率和高热容能改善叠靶的性能.对于单脉冲,钽-石墨层厚比为1∶1时,石墨能全部吸收相邻钽层的热沉积,轫致辐射效率为35.4%;4脉冲情况下,钽-石墨层厚比应为1∶13,总轫致辐射效率降到19.9%.考虑轫致辐射剂量和质量,钽-石墨两者的厚度比为1∶5时,钽层的总厚度应为1.2 mm;当钽-石墨层厚比为1:10时,钽层的总厚应降到0.7 mm.

  12. Optics of High-Energy Beams

    Energy Technology Data Exchange (ETDEWEB)

    Chamberlain, Owen

    1960-05-01

    Many of the experiments now being conducted on high-energy accelerators requires the use of beams of charged secondary particles. It is worth while at this time to attempt to summarize information about some of the most useful methods of setting up such beams. We are not concerned here with the primary beam of the accelerator. Rather, they assume that a target is struck by the primary beam and that it is desired to form a beam from the secondary charged particles that emerge from collisions within the target. The simplest system of forming this beam of secondary particles involves the use of magnetic fields only. In most cases it is desirable to obtain a beam of particles of known magnetic rigidity, or momentum. The bulk of this article is addressed to this problem. Some comments are also made about the use of electric fields in conjunction with magnetic fields. The inclusion of electric fields allows the separation of a beam of known momentum into its various components according to the velocities of the particles, hence according to the masses of the particles. These are referred to as ''separated beams''.

  13. Dynamic Characteristics of Growing Modes of Raman Instability from Intense Laser Beam Propagating Through Plasma

    Institute of Scientific and Technical Information of China (English)

    LIU Shi-Bing; CHEN Tao; CHEN Shi-Gang

    2004-01-01

    An essential dispersion relation,which can describe the dynamic properties of stimulated Raman scattering instability as a laser beam propagates through plasmas,is derived analytically.The development of growth mode,angle distribution,and temperature dependence of the instabilities are presented by solving this dispersion relation numerically.A significant dynamic characteristic has been revealed that the temperature increasing of the electron would result in redshift of scattered spectrum at high laser intensities.Furthermore,a novel modulational instability with double-peak temporal structure appears in a limited density region because of the coupling of scattered upshift and downshift waves.

  14. Orbital angular momentum of the laser beam and the second order intensity moments

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    From the wave equation of a generalized beam the orbital angular momentum is studied. It is shown that the orbital angular momentum exists not only in the Laguerre_Gaussian beam,but in any beam with an angular_dependent structure. By calculating the second order intensity moments of the beam the relation between the orbital angular momentum and the second order moments 〈xθy〉, 〈yθx〉 is given. As an example the orbital angular momentum of the general astigmatic Gaussian beam is studied.

  15. Orbital angular momentum of the laser beam and the second order intensity moments

    Institute of Scientific and Technical Information of China (English)

    高春清[1; 魏光辉[2; HorstWeber[3

    2000-01-01

    From the wave equation of a generalized beam the orbital angular momentum is studied. It is shown that the orbital angular momentum exists not only in the Laguerre-Gaussian beam, but in any beam with an angular-dependent structure. By calculating the second order intensity moments of the beam the relation between the orbital angular momentum and the second order moments 〈xθy〉, 〈yθx〉 is given. As an example the orbital angular momentum of the general astigmatic Gaussian beam is studied.

  16. Study on the beam shaping of high-power laser diode bars

    Institute of Scientific and Technical Information of China (English)

    Wei Huang(黄伟); Xiaodong Zeng(曾晓东); Yuying An(安毓英)

    2003-01-01

    Based on the Collins form, the intensity distribution of the resulting beam is derived when Gaussian beamsof a high-power laser diode bar pass through a paraxial optical system. Then flattop beam profiles areobtained by a concave cylindrical lens, and the propagation properties are discussed in detail, such as thepeak-intensity axis inclined at an angle γi. In addition, an expression to calculate beam angular width ispresented.

  17. Determination of Beam Intensity and Position in a Particle Accelerator

    CERN Document Server

    Kasprowicz, Grzegorz

    2010-01-01

    The Proton Synchrotron accelerator (PS), installed at CERN, although commissioned in 1959, still plays a central role in the production of beams for the Antiproton Decelerator, Super Proton Synchrotron, various experimental areas and for the Large Hadron Collider (LHC). The PS produces beams of different types of particles, mainly protons, but also various species of ions. Almost all these particle beams pass through the PS. The quality of the beams delivered to the LHC has a direct impact on the effective luminosity, and therefore the performance of the instrumentation of the PS is of great importance. The old trajec- tory and orbit measurement system of the PS dated back to 1988 and no longer fulfilled present day requirements. It used 40 beam position monitors (BPMs) and an analogue signal processing chain to acquire the trajectory of one single particle bunch out of many, over two consecutive turns at a maximum rate of once every 5ms. The BPMs were in good condition, however the electronics was aging and ...

  18. Demons deformable registration of CT and cone-beam CT using an iterative intensity matching approach

    Energy Technology Data Exchange (ETDEWEB)

    Nithiananthan, Sajendra; Schafer, Sebastian; Uneri, Ali [Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205 (United States); and others

    2011-04-15

    Purpose: A method of intensity-based deformable registration of CT and cone-beam CT (CBCT) images is described, in which intensity correction occurs simultaneously within the iterative registration process. The method preserves the speed and simplicity of the popular Demons algorithm while providing robustness and accuracy in the presence of large mismatch between CT and CBCT voxel values (''intensity''). Methods: A variant of the Demons algorithm was developed in which an estimate of the relationship between CT and CBCT intensity values for specific materials in the image is computed at each iteration based on the set of currently overlapping voxels. This tissue-specific intensity correction is then used to estimate the registration output for that iteration and the process is repeated. The robustness of the method was tested in CBCT images of a cadaveric head exhibiting a broad range of simulated intensity variations associated with x-ray scatter, object truncation, and/or errors in the reconstruction algorithm. The accuracy of CT-CBCT registration was also measured in six real cases, exhibiting deformations ranging from simple to complex during surgery or radiotherapy guided by a CBCT-capable C-arm or linear accelerator, respectively. Results: The iterative intensity matching approach was robust against all levels of intensity variation examined, including spatially varying errors in voxel value of a factor of 2 or more, as can be encountered in cases of high x-ray scatter. Registration accuracy without intensity matching degraded severely with increasing magnitude of intensity error and introduced image distortion. A single histogram match performed prior to registration alleviated some of these effects but was also prone to image distortion and was quantifiably less robust and accurate than the iterative approach. Within the six case registration accuracy study, iterative intensity matching Demons reduced mean TRE to (2.5{+-}2.8) mm

  19. Influence of conducting plate boundary conditions on the transverse envelope equations describing intense ion beam transport

    Directory of Open Access Journals (Sweden)

    Steven M. Lund

    2004-06-01

    Full Text Available In typical diagnostic applications, intense ion beams are intercepted by a conducting plate associated with devices used to measure beam phase-space projections. This results in the transverse space-charge field near the plate being shorted out, rendering simple envelope models with constant space-charge strength inaccurate. Here we develop corrected envelope models based on analytical calculations to account for this effect on the space-charge term of the envelope equations, thereby removing a systematic source of error in the equations and enabling more accurate comparisons with experiment. For common intense beam parameters, we find that the envelope correction occurs primarily in the envelope angles near the plate and that the effect can be large enough to degrade precision beam matching in periodic transport lattices. Results are verified with 3D self-consistent particle-in-cell simulations based on intense beam experiments associated with driver development for heavy-ion fusion.

  20. Stabilization of the Beam Intensity in the Linac at the CTF3 CLIC Test Facility

    CERN Document Server

    Dubrovskiy, A; Bathe, BN; Srivastava, S

    2013-01-01

    A new electron beam stabilization system has been introduced in CTF3 in order to open new possibilities for CLIC beam studies in ultra-stable conditions and to provide a sustainable tool to keep the beam intensity and energy at its reference values for long term operations. The stabilization system is based on a pulse-to-pulse feedback control of the electron gun to compensate intensity deviations measured at the end of the injector and at the beginning of the linac. Thereby it introduces negligible beam distortions at the end of the linac and it significantly reduces energy deviations. A self-calibration mechanism has been developed to automatically configure the feedback controller for the optimum performance. The residual intensity jitter of 0.045% of the stabilized beam was measured whereas the CLIC requirement is 0.075%.

  1. Longitudinal tracking studies for a high intensity proton synchrotron

    Energy Technology Data Exchange (ETDEWEB)

    Lessner, E.; Cho, Y.; Harkay, K.; Symon, K. [Argonne National Laboratory, 9700 Cass Ave., Argonne, Illinois 60439 (United States)

    1996-06-01

    Results from longitudinal tracking studies for a high intensity proton synchrotron designed for a 1-MW spallation source are presented. The machine delivers a proton beam of 0.5 mA time-averaged current at a repetition rate of 30 Hz. The accelerator is designed to have radiation levels that allow hands-on-maintenance. However, the high beam intensity causes strong space charge fields whose effects may lead to particle loss and longitudinal instabilities. The space charge fields modify the particle distribution, distort the stable bucket area and reduce the rf linear restoring force. Tracking simulations were conducted to analyze the space charge effects on the dynamics of the injection and acceleration processes and means to circumvent them. The tracking studies led to the establishment of the injected beam parameters and rf voltage program that minimized beam loss and longitudinal instabilities. Similar studies for a 10-GeV synchrotron that uses the 2-GeV synchrotron as its injector are also discussed. {copyright} {ital 1996 American Institute of Physics.}

  2. Intense heavy ion beam-induced effects in carbon-based stripper foils

    Energy Technology Data Exchange (ETDEWEB)

    Kupka, Katharina

    2016-08-15

    Amorphous carbon or carbon-based stripper foils are commonly applied in accelerator technology for electron stripping of ions. At the planned facility for antiproton and ion research (FAIR) at the Helmholtzzentrum fuer Schwerionenforschung (GSI), Darmstadt, thin carbon stripper foils provide an option for directly delivering ions of intermediate charge states to the heavy ion synchrotron, SIS 18, in order to mitigate space charge limitations during high-intensity operation. In case of desired high end-energies in the synchrotron, a second stripping process by a thicker carbon foil provides ions of higher charge states for injection into the SIS18. High beam intensities and a pulsed beam structure as foreseen at FAIR pose new challenges to the stripper foils which experience enhanced degradation by radiation damage, thermal effects, and stress waves. In order to ensure reliable accelerator operation, radiation-hard stripper foils are required. This thesis aims to a better understanding of processes leading to degradation of carbon-based thin foils. Special focus is placed on ion-beam induced structure and physical property changes and on the influence of different beam parameters. Irradiation experiments were performed at the M3-beamline of the universal linear accelerator (UNILAC) at GSI, using swift heavy ion beams with different pulse lengths and repetition rates. Tested carbon foils were standard amorphous carbon stripper foils produced by the GSI target laboratory, as well as commercial amorphous and diamond-like carbon foils and buckypaper foils. Microstructural changes were investigated with various methods such as optical microscopy, scanning electron microscopy (SEM), profilometry and chromatic aberration measurements. For the investigation of structural changes X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), in-situ Fourier-transform infrared spectroscopy (FTIR) and small angle X

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-10-31

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

  4. Lie algebraic analysis for the nonlinear transport of intense bunched beam in electrostatic quadrupoles

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhuo; L(U) Jian-Qin

    2008-01-01

    In this paper, the nonlinear transport of intense bunched beams in electrostatic quadrupoles is analyzed using the Lie algebraic method, and the results are briefly presented of the linear matrix approximation and the second order correction of particle trajectory in the state space. Beam having K-V distribution and Gaussian distribution approximation are respectively considered. A brief discussion is also given of the total effects of the quadrupole and the space charge forces on the evolution of the beam envelope.

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

    Science.gov (United States)

    Ho, F C; Dobrowolski, J A

    1992-07-01

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

  6. High Intensity Interval Training: New Insights

    Institute of Scientific and Technical Information of China (English)

    Martin J.Gibala

    2008-01-01

    @@ KEY POINTS ·High-intensity interval training(HIT)is characterized by repeated sessions of relatively brief,intermittent exercise.often performed with an“a11 out”effort or at an intensity close to that which elicits peak oxygen uptake(i.e.,≥90%of VO2 peak).

  7. High Intensity Exercise in Multiple Sclerosis

    DEFF Research Database (Denmark)

    Wens, Inez; Dalgas, Ulrik; Vandenabeele, Frank

    2015-01-01

    Introduction Low-to-moderate intensity exercise improves muscle contractile properties and endurance capacity in multiple sclerosis (MS). The impact of high intensity exercise remains unknown. Methods Thirty-four MS patients were randomized into a sedentary control group (SED, n = 11) and 2...

  8. High-intensity positron microprobe at Jefferson Lab

    CERN Document Server

    Golge, Serkan; Wojtsekhowski, Bogdan

    2014-01-01

    We present a conceptual design for a novel continuous wave electron-linac based high-intensity slow-positron production source with a projected intensity on the order of 10$^{10}$ e$^+$/s. Reaching this intensity in our design relies on the transport of positrons (T$_+$ below 600 keV) from the electron-positron pair production converter target to a low-radiation and low-temperature area for moderation in a high-efficiency cryogenic rare gas moderator, solid Ne. The performance of the integrated beamline has been verified through computational studies. The computational results include Monte Carlo calculations of the optimized electron/positron beam energies, converter target thickness, synchronized raster system, transport of the beam from the converter target to the moderator, extraction of the beam from the channel, and moderation efficiency calculations. For the extraction of positrons from the magnetic channel a magnetic field terminator plug prototype has been built and experimental data on the effective...

  9. Pump Intensity Dependence of Two-Beam Coupling in Doped Lithium Niobate Crystals

    Institute of Scientific and Technical Information of China (English)

    Nouel Y.Kamber; XU Jing-Jun; Sonia M. Mikha; SONG Feng; ZHANG Guo-Quan; ZHANG Xin-Zheng; LIU Si-Min; ZHANG Guang-Yin

    2000-01-01

    We demonstrated experimentally the dependence of two-beam coupling on the incident pump intensity in our samples of doped LiNbO3 crystals. Our results show that there is an optimum pump intensity for the signal beam amplification, which can be easily controlled by doping the LiNbO3 crystal with suitable concentrations of Fe and damage-resistant dopants such as Mg, In, and Zn.

  10. Intense, brilliant micro γ-beams in nuclear physics and applications

    Science.gov (United States)

    Habs, D.; Gasilov, S.; Lang, C.; Thirolf, P. G.; Jentschel, M.; Diehl, R.; Schroer, C.; Barty, C. P. J.; Zamfir, N. V.

    2011-06-01

    The upcoming γ facilities MEGa-Ray (Livermore) and ELI-NP (Bucharest) will have a 105 times higher γ flux F0 = 1013/s and a ~30 times smaller band width (ΔEγ/Eγ = BW ~ 10-3) than the presently best γ beam facility. They will allow to extract a small γ beam of about 30 - 100 μm radius 1 m behind the γ production point, containing the dominant γ energy band width. One can collimate the γ beam down to ΘBW = √ BW/ γe , where γe = Ee/ mec2 is a measure of the energy Ee of the electron beam, from which the γ beam is produced by Compton back-scattering. Due to the γ energy - angle correlation, the angular collimation results at the same time in a reduction of the γ beam band width without loss of "good" γ quanta, however, the primary γ flux F0is reduced to about Fcoll ~ F0 . 1.5 . ΔEγ/Eγ. For γ rays in the (0.1-100) MeV range, the negative real part δ of the index of refraction n = 1- δ + iβ from coherent Rayleigh scattering (virtual photo effect) dominates over the positive δ contributions from coherent virtual Compton scattering and coherent virtual pair creation scattering (Delbrück scattering). The very small absolute value |δ| ~ 10-6 - 10-9 of the index of refraction of matter for hard X-rays and γ-rays and its negative sign--in contrast to usual optics--results in a very different γ-ray optics, e.g. focusing lenses become concave and we use stacks of N optimized lenses. It requires very small radii of curvature of the γ lenses and thus very small γ beam radii. This leads to a technical new solution, where the primary γ beam is subdivided into M γ beamlets, which do not interfere with each other, but contribute with their independent intensities. We send the γ beamlets into a two-dimensional array of closely packed cylindrical parabolic refractive lenses, where N ~ 103 lenses with very small radius of curvature are stacked behind each other, leading to contracted beam spots in one dimension. With a second 1D lens system turned by

  11. Highly Compressed Ion Beams for High Energy Density Science

    CERN Document Server

    Friedman, Alex; Briggs, Richard J; Callahan, Debra; Caporaso, George; Celata, C M; Davidson, Ronald C; Faltens, Andy; Grant-Logan, B; Grisham, Larry; Grote, D P; Henestroza, Enrique; Kaganovich, Igor D; Lee, Edward; Lee, Richard; Leitner, Matthaeus; Nelson, Scott D; Olson, Craig; Penn, Gregory; Reginato, Lou; Renk, Tim; Rose, David; Sessler, Andrew M; Staples, John W; Tabak, Max; Thoma, Carsten H; Waldron, William; Welch, Dale; Wurtele, Jonathan; Yu, Simon

    2005-01-01

    The Heavy Ion Fusion Virtual National Laboratory (HIF-VNL) is developing the intense ion beams needed to drive matter to the High Energy Density (HED) regimes required for Inertial Fusion Energy (IFE) and other applications. An interim goal is a facility for Warm Dense Matter (WDM) studies, wherein a target is heated volumetrically without being shocked, so that well-defined states of matter at 1 to 10 eV are generated within a diagnosable region. In the approach we are pursuing, low to medium mass ions with energies just above the Bragg peak are directed onto thin target "foils," which may in fact be foams or "steel wool" with mean densities 1% to 100% of solid. This approach complements that being pursued at GSI, wherein high-energy ion beams deposit a small fraction of their energy in a cylindrical target. We present the requirements for warm dense matter experiments, and describe suitable accelerator concepts, including novel broadband traveling wave pulse-line, drift-tube linac, RF, and single-gap approa...

  12. High-intensity training in football.

    Science.gov (United States)

    Iaia, F Marcello; Rampinini, Ermanno; Bangsbo, Jens

    2009-09-01

    This article reviews the major physiological and performance effects of aerobic high-intensity and speed-endurance training in football, and provides insight on implementation of individual game-related physical training. Analysis and physiological measurements have revealed that modern football is highly energetically demanding, and the ability to perform repeated high-intensity work is of importance for the players. Furthermore, the most successful teams perform more high-intensity activities during a game when in possession of the ball. Hence, footballers need a high fitness level to cope with the physical demands of the game. Studies on football players have shown that 8 to 12 wk of aerobic high-intensity running training (> 85% HR(max)) leads to VO2(max) enhancement (5% to 11%), increased running economy (3% to 7%), and lower blood lactate accumulation during submaximal exercise, as well as improvements in the yo-yo intermittent recovery (YYIR) test performance (13%). Similar adaptations are observed when performing aerobic high-intensity training with small-sided games. Speed-endurance training has a positive effect on football-specific endurance, as shown by the marked improvements in the YYIR test (22% to 28%) and the ability to perform repeated sprints (approximately 2%). In conclusion, both aerobic and speed-endurance training can be used during the season to improve high-intensity intermittent exercise performance. The type and amount of training should be game related and specific to the technical, tactical, and physical demands imposed on each player.

  13. Quantification of beam complexity in intensity-modulated radiation therapy treatment plans

    Energy Technology Data Exchange (ETDEWEB)

    Du, Weiliang, E-mail: wdu@mdanderson.org; Cho, Sang Hyun; Zhang, Xiaodong; Kudchadker, Rajat J. [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Hoffman, Karen E. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    2014-02-15

    Purpose: Excessive complexity in intensity-modulated radiation therapy (IMRT) plans increases the dose uncertainty, prolongs the treatment time, and increases the susceptibility to changes in patient or target geometry. To date, the tools for quantitative assessment of IMRT beam complexity are still lacking. In this study, The authors have sought to develop metrics to characterize different aspects of beam complexity and investigate the beam complexity for IMRT plans of different disease sites. Methods: The authors evaluated the beam complexity scores for 65 step-and-shoot IMRT plans from three sites (prostate, head and neck, and spine) and 26 volumetric-modulated arc therapy (VMAT) plans for the prostate. On the basis of the beam apertures and monitor unit weights of all segments, the authors calculated the mean aperture area, extent of aperture shape irregularity, and degree of beam modulation for each beam. Then the beam complexity values were averaged to obtain the complexity metrics of the IMRT plans. The authors studied the correlation between the beam complexity metrics and the quality assurance (QA) results. Finally, the effects of treatment planning parameters on beam complexity were studied. Results: The beam complexity scores were not uniform among the prostate IMRT beams from different gantry angles. The lateral beams had larger monitor units and smaller shape irregularity, while the anterior-posterior beams had larger modulation values. On average, the prostate IMRT plans had the smallest aperture irregularity, beam modulation, and normalized monitor units; the head and neck IMRT plans had large beam irregularity and beam modulation; and the spine stereotactic radiation therapy plans often had small beam apertures, which may have been associated with the relatively large discrepancies between planned and QA measured doses. There were weak correlations between the beam complexity scores and the measured dose errors. The prostate VMAT beams showed

  14. High spin isomer beam line at RIKEN

    Energy Technology Data Exchange (ETDEWEB)

    Kishida, T.; Ideguchi, E.; Wu, H.Y. [Institute of Physical and Chemical Research, Saitama (Japan)] [and others

    1996-12-31

    Nuclear high spin states have been the subject of extensive experimental and theoretical studies. For the production of high spin states, fusion reactions are usually used. The orbital angular momentum brought in the reaction is changed into the nuclear spin of the compound nucleus. However, the maximum induced angular momentum is limited in this mechanism by the maximum impact parameter of the fusion reaction and by the competition with fission reactions. It is, therefore, difficult to populate very high spin states, and as a result, large {gamma}-detector arrays have been developed in order to detect subtle signals from such very high spin states. The use of high spin isomers in the fusion reactions can break this limitation because the high spin isomers have their intrinsic angular momentum, which can bring the additional angular momentum without increasing the excitation energy. There are two methods to use the high spin isomers for secondary reactions: the use of the high spin isomers as a target and that as a beam. A high spin isomer target has already been developed and used for several experiments. But this method has an inevitable shortcoming that only {open_quotes}long-lived{close_quotes} isomers can be used for a target: {sup 178}Hf{sup m2} (16{sup +}) with a half-life of 31 years in the present case. By developing a high spin isomer beam, the authors can utilize various short-lived isomers with a short half-life around 1 {mu}s. The high spin isomer beam line of RIKEN Accelerator Facility is a unique apparatus in the world which provides a high spin isomer as a secondary beam. The combination of fusion-evaporation reaction and inverse kinematics are used to produce high spin isomer beams; in particular, the adoption of `inverse kinematics` is essential to use short-lived isomers as a beam.

  15. Non-perturbative measurement of low-intensity charged particle beams

    Science.gov (United States)

    Fernandes, M.; Geithner, R.; Golm, J.; Neubert, R.; Schwickert, M.; Stöhlker, T.; Tan, J.; Welsch, C. P.

    2017-01-01

    Non-perturbative measurements of low-intensity charged particle beams are particularly challenging to beam diagnostics due to the low amplitude of the induced electromagnetic fields. In the low-energy antiproton decelerator (AD) and the future extra low energy antiproton rings at CERN, an absolute measurement of the beam intensity is essential to monitor the operation efficiency. Superconducting quantum interference device (SQUID) based cryogenic current comparators (CCC) have been used for measuring slow charged beams in the nA range, showing a very good current resolution. But these were unable to measure fast bunched beams, due to the slew-rate limitation of SQUID devices and presented a strong susceptibility to external perturbations. Here, we present a CCC system developed for the AD machine, which was optimised in terms of its current resolution, system stability, ability to cope with short bunched beams, and immunity to mechanical vibrations. This paper presents the monitor design and the first results from measurements with a low energy antiproton beam obtained in the AD in 2015. These are the first CCC beam current measurements ever performed in a synchrotron machine with both coasting and short bunched beams. It is shown that the system is able to stably measure the AD beam throughout the entire cycle, with a current resolution of 30 {nA}.

  16. Average intensity and spreading of partially coherent model beams propagating in a turbulent biological tissue

    Science.gov (United States)

    Wu, Yuqian; Zhang, Yixin; Wang, Qiu; Hu, Zhengda

    2016-11-01

    For Gaussian beams with three different partially coherent models, including Gaussian-Schell model (GSM), Laguerre-Gaussian Schell-model (LGSM) and Bessel-Gaussian Schell-model (BGSM) beams propagating through a biological turbulent tissue, the expression of the spatial coherence radius of a spherical wave propagating in a turbulent biological tissue, and the average intensity and beam spreading for GSM, LGSM and BGSM beams are derived based on the fractal model of power spectrum of refractive-index variations in biological tissue. Effects of partially coherent model and parameters of biological turbulence on such beams are studied in numerical simulations. Our results reveal that the spreading of GSM beams is smaller than LGSM and BGSM beams on the same conditions, and the beam with larger source coherence width has smaller beam spreading than that with smaller coherence width. The results are useful for any applications involved light beam propagation through tissues, especially the cases where the average intensity and spreading properties of the light should be taken into account to evaluate the system performance and investigations in the structures of biological tissue.

  17. Beam dump system design for 100 MeV high intensity proton cyclotron%100 MeV强流质子回旋加速器束流调试靶系统

    Institute of Scientific and Technical Information of China (English)

    贾先禄; 张天爵; 王峰; 吕银龙; 魏素敏; 毕远杰; 宋国芳; 解怀东

    2013-01-01

    中国原子能科学研究院正在建造一台100 MeV,200 μA的强流质子回旋加速器,需要使用束流调试靶来调试加速器,为此设计了一套束流功率为20 kW的质子束调试系统.对该系统的束流输运线、靶材料的选取、靶结构、水冷计算、屏蔽结构等作了介绍.给出了整条束流输运线的匹配计算结果;通过对质子打靶后的中子产额、角通量、靶的活化等方面的比较,最终选用铝作为靶材料;根据加速器引出束流能量和功率,设计了分层式靶结构,同时对靶进行了水冷计算;打靶产生的出射粒子平均能量较高,导致产生的辐射剂量很大,考虑到对环境与工作人员的影响及费用,需要对其进行局部屏蔽,给出了屏蔽计算结果及屏蔽结构的设计.%A 100 MeV proton cyclotron, referred to as CYCIAE-100, is designed to provide proton beams with energy up to 200 μA. When the cyclotron is under commissioning, a beam dump is required to measure the beam with a power of 20 kW. The paper introduces the beam line, target material selecting, target configuration, cooling calculation and the local shielding structure. The calculation result of the beam line matching is given. After comparing the neutron yield, flux angle and thermal activation of the targets of different materials by the proton targeting, the aluminum is selected as the target material. Based on the extraction beam energy and power of the cyclotron, a layered target configuration is designed, and the cooling calculation result is presented. The average energy of the emergent particle produced by the proton targeting is relatively high, so it will produce large radiation dose. Considering the harmful effect on the environment and personnel, the local shielding is selected for use. The calculation result and configuration of the local shielding are also presented in the paper.

  18. Quantitative high dynamic range beam profiling for fluorescence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, T. J., E-mail: t.j.mitchell@dur.ac.uk; Saunter, C. D.; O’Nions, W.; Girkin, J. M.; Love, G. D. [Centre for Advanced Instrumentation and Biophysical Sciences Institute, Department of Physics, Durham University, Durham DH1 3LE (United Kingdom)

    2014-10-15

    Modern developmental biology relies on optically sectioning fluorescence microscope techniques to produce non-destructive in vivo images of developing specimens at high resolution in three dimensions. As optimal performance of these techniques is reliant on the three-dimensional (3D) intensity profile of the illumination employed, the ability to directly record and analyze these profiles is of great use to the fluorescence microscopist or instrument builder. Though excitation beam profiles can be measured indirectly using a sample of fluorescent beads and recording the emission along the microscope detection path, we demonstrate an alternative approach where a miniature camera sensor is used directly within the illumination beam. Measurements taken using our approach are solely concerned with the illumination optics as the detection optics are not involved. We present a miniature beam profiling device and high dynamic range flux reconstruction algorithm that together are capable of accurately reproducing quantitative 3D flux maps over a large focal volume. Performance of this beam profiling system is verified within an optical test bench and demonstrated for fluorescence microscopy by profiling the low NA illumination beam of a single plane illumination microscope. The generality and success of this approach showcases a widely flexible beam amplitude diagnostic tool for use within the life sciences.

  19. Hamiltonian maps and normal forms for intense beams

    Energy Technology Data Exchange (ETDEWEB)

    Turchetti, G. [Dipartimento di Fisica Universita di Bologna and INFN, Bologna, Via Irnerio 46, 40126 (Italy)]. E-mail: turchetti@bo.infn.it

    2006-06-01

    The dynamics of a beam in a ring with a localized multipolar nonlinearity is described by a polynomial one turn map. The space charge forces act continuously along the ring, but their effect can be included by replacing the linear tune with the depressed tune which depends on the Courant Snyder invariant. This approximation allows to use the normal forms to compute the nonlinear invariants, the nonlinear tune and the islands geometric parameters when a low order resonance is approached.

  20. Low Energy High Brilliance Beam Characterization

    CERN Document Server

    Bähr, J

    2005-01-01

    Low energy high brilliance beam characterization plays an important role for electron sources and injectors of Free Electron Lasers (FELs) and electron linear accelerators as for example the future ILC project. The topic is discussed basing on solutions of the PITZ facility (PhotoInjector Test facility Zeuthen) which are compared with methods applied at other facilities. The properties of an electron beam produced at a laser-driven rf-gun is mainly influenced also by characteristics of the laser beam and the electron gun itself. Therefore aspects of diagnostics will be also discussed for the laser, laser beam line and gun as well. The main properties of the electron beam are transverse and longitudinal phase space and charge as well. The measurement of transverse beam size and position, transverse emittance, charge, beam current, and longitudinal phase space will be discussed in detail. The measurements of the transverse emittance at PITZ is based on a single slit method. The measurement of the longitudinal p...

  1. Shaping the longitudinal intensity pattern of Cartesian beams in lossless and lossy media

    Science.gov (United States)

    Corato-Zanarella, Mateus; Corato-Zanarella, Henrique; Zamboni-Rached, Michel

    2017-09-01

    Several applications, such as optical tweezers and atom guiding, benefit from techniques that allow the engineering of spatial field profiles, in particular their longitudinal intensity patterns. In cylindrical coordinates, methods such as frozen waves allow an advanced control of beam characteristics, but in Cartesian coordinates there is no analogous technique. Since Cartesian beams may also be useful in applications, we develop here a method to modulate on demand the longitudinal intensity pattern of any (initially) unidimensional Cartesian beam with concentrated angular spectrum (thus encompassing all unidimensional paraxial beams) in lossless and lossy media. To this end, we write the total beam as a product of two unidimensional beams and explore the degree of freedom provided by the additional Cartesian coordinate. While in the plane where this coordinate is zero the chosen unidimensional beam keeps its structure with the additional desired intensity modulation, a sinusoidal-like oscillation appears in the direction of this variable and creates a spot whose size is tunable. Examples with Gaussian and Airy beams are presented and their corresponding experimental demonstrations in free-space are performed to show the validity of the method.

  2. Production of intense attosecond vector beam pulse trains based on harmonics

    Institute of Scientific and Technical Information of China (English)

    韩玉晶; 廖国前; 陈黎明; 李玉同; 王伟民; 张杰

    2015-01-01

    We provide the first report on the harmonics generated by an intense femtosecond vector beam that is normally incident on a solid target. By using 2D particle-in-cell (PIC) codes, we observe the third and the fifth harmonic signals with the same vector structure as the driving beam, and obtain an attosecond vector beam pulse train. We also show that the conversion efficiencies of the third and the fifth harmonics reach their maxima for a plasma density of four times the critical density due to the plasma resonating with the driving force. This method provides a new means of generating intense extreme ultraviolet (XUV) vector beams via ultra-intense laser-driven harmonics.

  3. Slant path average intensity of finite optical beam propagating in turbulent atmosphere

    Institute of Scientific and Technical Information of China (English)

    Yixin Zhang; Gaogang Wang

    2006-01-01

    The average intensity of finite laser beam propagating through turbulent atmosphere is calculated from the extended Huygens Fresnel principle. Formulas are presented for the slant path average intensity from an arbitrarily truncated Gaussian beam. The new expressions are derived from the modified von Karman spectrum for refractive-index fluctuations, quadratic approximation of the structure function,and Gaussian approximation for the product of Gaussian function and Bessel function. It is shown that the form of average intensity is not a Gaussian function but a polynomial of the power of the binomial function, Gaussian function, and the incomplete gamma function. The results also show that the mean irradiance of a finite optical beam propagating in slant path turbulent atmosphere not only depends on the effective beam radius at the transmitting aperture plane, propagation distance, and long-term lateral coherence length of spherical wave, but also on the radius of emit aperture.

  4. Improving oxidation resistance and thermal insulation of thermal barrier coatings by intense pulsed electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mei Xianxiu, E-mail: xxmei@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Liu Xiaofei; Wang Cunxia; Wang Younian; Dong Chuang [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Pulsed electron beam was used for sealing ZrO{sub 2} thermal barrier coating prepared by electron beam-physical vapor deposition. Black-Right-Pointing-Pointer At irradiation energy densities above 8 J/cm{sup 2}, ZrO{sub 2} ceramic coating surface was fully re-melted and became smooth, dense and shiny. Black-Right-Pointing-Pointer The thermal diffusion rate of the irradiated coating was decreased. Black-Right-Pointing-Pointer Thermal insulation properties and high temperature oxidation resistance were improved. - Abstract: In this paper, intense pulsed electron beam was used for the irradiation treatment of 6-8% Y{sub 2}O{sub 3}-stablized ZrO{sub 2} thermal barrier coating prepared by electron beam-physical vapor deposition to achieve the 'sealing' of columnar crystals, thus improving their thermal insulation properties and high temperature oxidation resistance. The electron beam parameters used were: pulse duration 200 {mu}s, electron voltage 15 kV, energy density 3, 5, 8, 15, 20 J/cm{sup 2}, and pulsed numbers 30. 1050 Degree-Sign C cyclic oxidation and static oxidation experiments were used for the research on oxidation resistance of the coatings. When the energy density of the electron beam was larger than 8 J/cm{sup 2}, ZrO{sub 2} ceramic coating surface was fully re-melted and became smooth, dense and shiny. The coating changed into a smooth polycrystalline structure, thus achieving the 'sealing' effect of the columnar crystals. After irradiations with the energy density of 8-15 J/cm{sup 2}, the thermally grown oxide coating thickness decreased significantly in comparison with non-irradiated coatings, showing that the re-melted coating improved the oxidation resistance of the coatings. The results of thermal diffusivity test by laser flash method showed that the thermal diffusion rate of the irradiated coating was lower than that of the coating without irradiation treatment, and the thermal

  5. Work in progress at the North Area High Intensity Facility (NAHIF)

    CERN Document Server

    1979-01-01

    The photo shows the exit of the two MBN-type magnets in tunnel TDC85 (upstream of TCC8), used to 'switch' the primary proton beam either towards target T8 (to the left) or onto target T10 (straight) to produce the H10 or the F12 (high-intensity electron/gamma) beam, respectively.

  6. Hyperenergetic manned aerospacecraft propelled by intense pulsed microwave power beam

    Science.gov (United States)

    Myrabo, Leik N.

    1995-09-01

    The objective of this research was to exploit wireless power transmission (microwave/millimeter)--to lower manned space transportation costs by two or three orders of magnitude. Concepts have been developed for lightweight, mass-producible, beam-propelled aerospacecraft called Lightcraft. The vehicles are designed for a 'mass-poor, energy-rich' (i.e. hyper-energentic flight infrastructure which utilizes remote microwave power stations to build an energy-beam highway to space. Although growth in laser power levels has lagged behind expectations, microwave and millimeter-wave source technology now exists for rapid scaling to the megawatt and gigawatt time-average power levels. The design exercise focused on the engine, structure, and receptive optics requirements for a 15 meter diameter, 5 person Earth- to-moon aerospacecraft. Key elements in the airbreathing accelerator propulsion system are: a) a 'flight-weight' 35GHz rectenna electric powerplant, b) microwave-induced 'Air Spike' and perimeter air-plasma generators, and c) MagnetoHydroDynamic-Fanjet engine with its superconducting magnets and external electrodes.

  7. Electron beam damage in high temperature polymers

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S. (Dayton Univ., OH (USA). Research Inst.); Adams, W.W. (Air Force Materials Lab., Wright-Patterson AFB, OH (USA))

    1990-01-01

    Electron microscopic studies of polymers are limited due to beam damage. Two concerns are the damage mechanism in a particular material, and the maximum dose for a material before damage effects are observed. From the knowledge of the dose required for damage to the polymer structure, optimum parameters for electron microscopy imaging can be determined. In the present study, electron beam damage of polymers has been quantified by monitoring changes in the diffraction intensity as a function of electron dose. The beam damage characteristics of the following polymers were studied: poly(p-phenylene benzobisthiazole) (PBZT); poly(p-phenylene benzobisoxazole) (PBO); poly(benzoxazole) (ABPBO); poly(benzimidazole) (ABPBI); poly(p-phenylene terephthalamide) (PPTA); and poly(aryl ether ether ketone) (PEEK). Previously published literature results on polyethylene (PE), polyoxymethylene (POM), nylon-6, poly(ethylene oxide) (PEO), PBZT, PPTA, PPX, iPS, poly(butylene terephthalate) (PBT), and poly(phenylene sulphide) (PPS) were reviewed. This study demonstrates the strong dependence of the electron beam resistivity of a polymer on its thermal stability/melt temperature. (author).

  8. Beam shaping to provide round and square-shaped beams in optical systems of high-power lasers

    Science.gov (United States)

    Laskin, Alexander; Laskin, Vadim

    2016-05-01

    Optical systems of modern high-power lasers require control of irradiance distribution: round or square-shaped flat-top or super-Gaussian irradiance profiles are optimum for amplification in MOPA lasers and for thermal load management while pumping of crystals of solid-state ultra-short pulse lasers to control heat and minimize its impact on the laser power and beam quality while maximizing overall laser efficiency, variable profiles are also important in irradiating of photocathode of Free Electron lasers (FEL). It is suggested to solve the task of irradiance re-distribution using field mapping refractive beam shapers like piShaper. The operational principle of these devices presumes transformation of laser beam intensity from Gaussian to flat-top one with high flatness of output wavefront, saving of beam consistency, providing collimated output beam of low divergence, high transmittance, extended depth of field, negligible residual wave aberration, and achromatic design provides capability to work with ultra-short pulse lasers having broad spectrum. Using the same piShaper device it is possible to realize beams with flat-top, inverse Gauss or super Gauss irradiance distribution by simple variation of input beam diameter, and the beam shape can be round or square with soft edges. This paper will describe some design basics of refractive beam shapers of the field mapping type and optical layouts of their applying in optical systems of high-power lasers. Examples of real implementations and experimental results will be presented as well.

  9. Using an intense laser beam in interaction with muon/electron beam to probe the Noncommutative QED

    CERN Document Server

    Tizchang, S; Haghighat, M; Mohammadi, R

    2016-01-01

    It is known that the linearly polarized photons can partly transform to circularly polarized ones via forward Compton scattering in a background such as the external magnetic field or noncommutative space time. Based on this fact we explore the effects of the NC-background on the scattering of a linearly polarized laser beam from an intense beam of charged leptons. We show that for a muon/electron beam flux $\\bar\\varepsilon_{\\mu,e}\\sim 10^{12}/10^{10}\\,{\\rm TeV}\\,{\\rm cm}^{-2}\\,{\\rm sec}^{-1}$ and a linearly polarized laser beam with energy $k^0\\sim $1 eV and average power $\\bar{P}_{\\rm laser}\\simeq$1 MW, the generation rate of circularly polarized photons is about $R_{_V} \\sim 10^4/{\\rm sec}$ for Noncommutative energy scale $\\Lambda_{\\tiny{NC}}\\sim 10$TeV. This is fairly large and can grow for more intense beams in near future.

  10. Scintillation screen materials for beam profile measurements of high energy ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Krishnakumar, Renuka

    2016-06-22

    For the application as a transverse ion beam diagnostics device, various scintillation screen materials were analysed. The properties of the materials such as light output, image reproduction and radiation stability were investigated with the ion beams extracted from heavy ion synchrotron SIS-18. The ion species (C, Ne, Ar, Ta and U) were chosen to cover the large range of elements in the periodic table. The ions were accelerated to the kinetic energies of 200 MeV/u and 300 MeV/u extracted with 300 ms pulse duration and applied to the screens. The particle intensity of the ion beam was varied from 10{sup 4} to 10{sup 9} particles per pulse. The screens were irradiated with typically 40 beam pulses and the scintillation light was captured using a CCD camera followed by characterization of the beam spot. The radiation hardness of the screens was estimated with high intensity Uranium ion irradiation. In the study, a linear light output for 5 orders of magnitude of particle intensities was observed from sensitive scintillators and ceramic screens such as Al{sub 2}O{sub 3}:Cr and Al{sub 2}O{sub 3}. The highest light output was recorded by CsI:Tl and the lowest one by Herasil. At higher beam intensity saturation of light output was noticed from Y and Mg doped ZrO{sub 2} screens. The light output from the screen depends not only on the particle intensity but also on the ion species used for irradiation. The light yield (i.e. the light intensity normalised to the energy deposition in the material by the ion) is calculated from the experimental data for each ion beam setting. It is shown that the light yield for light ions is about a factor 2 larger than the one of heavy ions. The image widths recorded exhibit a dependence on the screens material and differences up to 50 % were registered. On radiation stability analysis with high particle intensity of Uranium ions of about 6 x 10{sup 8} ppp, a stable performance in light output and image reproduction was documented from Al

  11. Holographic generation of highly twisted electron beams

    CERN Document Server

    Grillo, Vincenzo; Mafakheri, Erfan; Frabboni, Stefano; Karimi, Ebrahim; Boyd, Robert W

    2014-01-01

    Free electrons can possess an intrinsic orbital angular momentum, similar to those in an electron cloud, upon free-space propagation. The wavefront corresponding to the electron's wavefunction forms a helical structure with a number of twists given by the \\emph{angular speed}. Beams with a high number of twists are of particular interest because they carry a high magnetic moment about the propagation axis. Among several different techniques, electron holography seems to be a promising approach to shape a \\emph{conventional} electron beam into a helical form with large values of angular momentum. Here, we propose and manufacture a nano-fabricated phase hologram for generating a beam of this kind with an orbital angular momentum up to 200$\\hbar$. Based on a novel technique the value of orbital angular momentum of the generated beam are measured, then compared with simulations. Our work, apart from the technological achievements, may lead to a way of generating electron beams with a high quanta of magnetic momen...

  12. Intensity ratio measurements for density sensitive lines of highly charged Fe ions

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Safdar, E-mail: safdaruetian@gmail.com; Shimizu, Erina [Institute for Laser Science, The University of Electro-Communications (Japan); Sakaue, Hiroyuki A.; Kato, Daiji; Murakami, Izumi [National Institute for Fusion Science (Japan); Yamamoto, Norimasa [Chubu University (Japan); Hara, Hirohisa; Watanabe, Tetsuya [The Graduate University of Advanced Studies (SOKENDAI) (Japan); Nakamura, Nobuyuki, E-mail: n-nakamu@ils.uec.ac.jp [Institute for Laser Science, The University of Electro-Communications (Japan)

    2015-11-15

    Intensity ratio of density sensitive emission lines emitted from Fe ions in the extreme ultraviolet region is important for astrophysics applications. We report high-resolution intensity ratio measurements for Fe ions performed at Tokyo EBIT laboratory by employing a flat-field grazing incidence spectrometer. The experimental intensity ratios of Fe X and Fe XII are plotted as a function of electron density for different electron beam currents. The experimental results are compared with the predicted intensity ratios from the model calculations.

  13. Design of a compact Faraday cup for low energy, low intensity ion beams

    Science.gov (United States)

    Cantero, E. D.; Sosa, A.; Andreazza, W.; Bravin, E.; Lanaia, D.; Voulot, D.; Welsch, C. P.

    2016-01-01

    Beam intensity is one of the key parameters in particle accelerators, in particular during machine commissioning, but also during operation for experiments. At low beam energies and low intensities a number of challenges arise in its measurement as commonly used non-invasive devices are no longer sensitive enough. It then becomes necessary to stop the beam in order to measure its absolute intensity. A very compact Faraday cup for determining ion beam currents from a few nanoamperes down to picoamperes for the HIE-ISOLDE post-accelerator at CERN has been designed, built and tested with beam. It has a large aperture diameter of 30 mm and a total length of only 16 mm, making it one of the most compact designs ever used. In this paper we present the different steps that were involved in the design and optimization of this device, including beam tests with two early prototypes and the final monitor. We also present an analysis of the losses caused by secondary particle emission for different repelling electrode voltages and beam energies. Finally, we show that results obtained from an analytical model for electron loss probability combined with Monte Carlo simulations of particles trajectories provide a very good agreement with experimental data.

  14. Design of a compact Faraday cup for low energy, low intensity ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Cantero, E.D., E-mail: esteban.cantero@cern.ch [CERN, 1211 Geneva 23 (Switzerland); Sosa, A. [CERN, 1211 Geneva 23 (Switzerland); The University of Liverpool, Liverpool (United Kingdom); Andreazza, W.; Bravin, E.; Lanaia, D.; Voulot, D. [CERN, 1211 Geneva 23 (Switzerland); Welsch, C.P. [The University of Liverpool, Liverpool (United Kingdom); The Cockcroft Institute, Sci-Tech Daresbury, Daresbury, Warrington (United Kingdom)

    2016-01-21

    Beam intensity is one of the key parameters in particle accelerators, in particular during machine commissioning, but also during operation for experiments. At low beam energies and low intensities a number of challenges arise in its measurement as commonly used non-invasive devices are no longer sensitive enough. It then becomes necessary to stop the beam in order to measure its absolute intensity. A very compact Faraday cup for determining ion beam currents from a few nanoamperes down to picoamperes for the HIE-ISOLDE post-accelerator at CERN has been designed, built and tested with beam. It has a large aperture diameter of 30 mm and a total length of only 16 mm, making it one of the most compact designs ever used. In this paper we present the different steps that were involved in the design and optimization of this device, including beam tests with two early prototypes and the final monitor. We also present an analysis of the losses caused by secondary particle emission for different repelling electrode voltages and beam energies. Finally, we show that results obtained from an analytical model for electron loss probability combined with Monte Carlo simulations of particles trajectories provide a very good agreement with experimental data.

  15. Laser-driven beam lines for delivering intensity modulated radiation therapy with particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, K. M.; Schell, S.; Wilkens, J. J. [Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 München (Germany)

    2013-07-26

    Laser-accelerated particles can provide a promising opportunity for radiation therapy of cancer. Potential advantages arise from combining a compact, cost-efficient treatment unit with the physical advantages in dose delivery of charged particle beams. We consider different dose delivery schemes and the required devices to design a possible treatment unit. The secondary radiation produced in several beam line elements remains a challenge to be addressed.

  16. Production of a highly charged uranium ion beam with RIKEN superconducting electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Higurashi, Y.; Ohnishi, J.; Nakagawa, T.; Haba, H.; Fujimaki, M.; Komiyama, M.; Kamigaito, O. [RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Tamura, M.; Aihara, T.; Uchiyama, A. [SHI Accelerator Service Ltd., 1-17-6 Osaki, Shinagawa, Tokyo 141-0032 (Japan)

    2012-02-15

    A highly charged uranium (U) ion beam is produced from the RIKEN superconducting electron cyclotron resonance ion source using 18 and 28 GHz microwaves. The sputtering method is used to produce this U ion beam. The beam intensity is strongly dependent on the rod position and sputtering voltage. We observe that the emittance of U{sup 35+} for 28 GHz microwaves is almost the same as that for 18 GHz microwaves. It seems that the beam intensity of U ions produced using 28 GHz microwaves is higher than that produced using 18 GHz microwaves at the same Radio Frequency (RF) power.

  17. High Intensity Particle Physics at PW-class laser facilities

    Science.gov (United States)

    Bulanov, Stepan; Schroeder, Carl; Esarey, Eric; Esirkepov, Timur; Kando, Masaki; Rosanov, Nikolay; Korn, Georg; Bulanov, Sergey V.; Leemans, Wim P.

    2015-11-01

    The processes typical for high intensity particle physics, i.e., the interactions of charged particles with strong electromagnetic fields, have attracted considerable interest recently. Some of these processes, previously believed to be of theoretical interest only, are now becoming experimentally accessible. High intensity electromagnetic (EM) fields significantly modify the interactions of particles and EM fields, giving rise to the phenomena that are not encountered either in classical or perturbative quantum theory of these interactions. One of such phenomena is the radiation reaction, which radically influences the electron motion in an electromagnetic standing wave formed by two super-intense counter-propagating laser pulses. Depending on the laser intensity and wavelength, either classical or quantum mode of radiation reaction prevail, or both are strong. When radiation reaction dominates, electron motion evolves to limit cycles and strange attractors. This creates a new framework for high energy physics experiments on an interaction of energetic charged particle beams and colliding super-intense laser pulses. Work supported by U.S. DOE under Contract No. DE-AC02-05CH11231.

  18. SU-E-T-353: Decoding the Beam Complexity in Intensity-Modulated Radiation Therapy Plans

    Energy Technology Data Exchange (ETDEWEB)

    Du, W; Cho, S; Zhang, X; Hoffman, K; Kudchadker, R [UT MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-01

    Purpose: Modern IMRT relies on computers to generate treatment plans of varied complexity. A highly complex treatment plan may use a large number of small and irregular beam apertures in order to achieve high dose conformity. However, excessive beam complexity can increase dosimetric uncertainty, prolong treatment time, and increase susceptibility to target or organ motion. In this study we sought to develop metrics to assess the complexity of IMRT beams and plans. Methods: Based the information of leaf positions and MU for each beam segment, we calculated the following beam complexity metrics: aperture area, shape irregularity, and beam modulation. Then these beam complexity metrics were averaged to obtain the corresponding plan complexity metrics, using the beam MUs as weighting factors. We evaluated and compared the beam and plan complexity scores for 65 IMRT plans from 3 sites (prostate, head and neck, and spine). We also studied how the plan complexity scores were affected by adjusting inverse planning parameters. Results: For prostate IMRT, the lateral beams had large MUs and smaller shape irregularity, while the anterior or posterior beams had larger modulation values. On average, the prostate IMRT plans had the smallest shape irregularity and beam modulation; the HN IMRT plans had the largest aperture area, shape irregularity, and beam modulation; and the spine stereotactic IMRT plans often had small aperture area, which may be associated with relatively large discrepancies between calculated and measures doses. The plan complexity increased as the number of optimization iterations and the number of beam segments increased and as the minimum segment area decreased. Conclusion: Complexity of IMRT beams and plans were quantified in terms of aperture area, shape irregularity and beam modulation. The complexity metrics varied among IMRT plans for different disease sites and were affected when the planning parameters were adjusted.

  19. Novel high-energy physics studies using intense lasers and plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Leemans, Wim P. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bulanov, Stepan [Univ. of California, Berkeley, CA (United States); Esarey, Eric [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schroeder, Carl [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-06-29

    In the framework of the project “Novel high-energy physics studies using intense lasers and plasmas” we conducted the study of ion acceleration and “flying mirrors” with high intensity lasers in order to develop sources of ion beams and high frequency radiation for different applications. Since some schemes of laser ion acceleration are also considered a good source of “flying mirrors”, we proposed to investigate the mechanisms of “mirror” formation. As a result we were able to study the laser ion acceleration from thin foils and near critical density targets. We identified several fundamental factors limiting the acceleration in the RPA regime and proposed the target design to compensate these limitations. In the case of near critical density targets, we developed a concept for the laser driven ion source for the hadron therapy. Also we studied the mechanism of “flying mirror” generation during the intense laser interaction with thin solid density targets. As for the laser-based positron creation and capture we initially proposed to study different regimes of positron beam generation and positron beam cooling. Since the for some of these schemes a good quality electron beam is required, we studied the generation of ultra-low emittance electron beams. In order to understand the fundamental physics of high energy electron beam interaction with high intensity laser pulses, which may affect the efficient generation of positron beams, we studied the radiation reaction effects.

  20. Production of High-Intensity, Highly Charged Ions

    OpenAIRE

    S. GamminoINFN, LNS, Catania

    2014-01-01

    In the past three decades, the development of nuclear physics facilities for fundamental and applied science purposes has required an increasing current of multicharged ion beams. Multiple ionization implies the formation of dense and energetic plasmas, which, in turn, requires specific plasma trapping configurations. Two types of ion source have been able to produce very high charge states in a reliable and reproducible way: electron beam ion sources (EBIS) and electron cyc...

  1. High energy electron beams for ceramic joining

    Energy Technology Data Exchange (ETDEWEB)

    Turman, B.N.; Glass, S.J.; Halbleib, J.A.; Helmich, D.R.; Loehman, R.E. [Sandia National Labs., Albuquerque, NM (United States); Clifford, J.R. [Titan Corp., Albuquerque, NM (United States)

    1994-12-31

    Joining of structural ceramics is possible using high melting point metals such as Mo and Pt that are heated with a high energy electron beam, with the potential for high temperature joining. A 10 MeV electron beam can penetrate through 1 cm of ceramic, offering the possibility of buried interface joining. Because of transient heating and the lower heat capacity of the metal relative to the ceramic, a pulsed high power beam has the potential for melting the metal without decomposing or melting the ceramic. We have demonstrated the feasibility of the process with a series of 10 MeV, 1 kW electron beam experiments. Shear strengths up to 28 MPa have been measured. This strength is comparable to that reported in the literature for bonding silicon nitride to molybdenum with copper-silver-titanium braze, but weaker than that reported for Si{sub 3}N{sub 4}-Si{sub 3}N{sub 4} with gold-nickel braze. The bonding mechanism appears to be a thin silicide layer.

  2. First test of BNL electron beam ion source with high current density electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Pikin, Alexander, E-mail: pikin@bnl.gov; Alessi, James G., E-mail: pikin@bnl.gov; Beebe, Edward N., E-mail: pikin@bnl.gov [Brookhaven National Laboratory, Upton, NY 11973 (United States); Shornikov, Andrey; Mertzig, Robert; Wenander, Fredrik; Scrivens, Richard [CERN, CH-1211 Geneva 23 (Switzerland)

    2015-01-09

    A new electron gun with electrostatic compression has been installed at the Electron Beam Ion Source (EBIS) Test Stand at BNL. This is a collaborative effort by BNL and CERN teams with a common goal to study an EBIS with electron beam current up to 10 A, current density up to 10,000 A/cm{sup 2} and energy more than 50 keV. Intensive and pure beams of heavy highly charged ions with mass-to-charge ratio < 4.5 are requested by many heavy ion research facilities including NASA Space Radiation Laboratory (NSRL) at BNL and HIE-ISOLDE at CERN. With a multiampere electron gun, the EBIS should be capable of delivering highly charged ions for both RHIC facility applications at BNL and for ISOLDE experiments at CERN. Details of the electron gun simulations and design, and the Test EBIS electrostatic and magnetostatic structures with the new electron gun are presented. The experimental results of the electron beam transmission are given.

  3. Acceleration of injected electron beam by ultra-intense laser pulses with phase disturbances

    CERN Document Server

    Nakamura, T; Kato, S; Tanimoto, M; Koyama, K; Koga, J

    2003-01-01

    Acceleration of an injected electron beam by ultra-intense laser pulses with phase disturbances is investigated. The energy gain of the beam electrons depends on the initial energy of the injected electrons in the stochastic acceleration process. The effect is larger for electrons with some injection energy as opposed to electrons with no initial energy. The corresponding accelerating field for electrons having certain amounts of initial energy becomes larger than that of the standard wakefield. (author)

  4. Stimulated Raman backscattering at high laser intensities

    Energy Technology Data Exchange (ETDEWEB)

    Skoric, M.M. [Vinca Inst. of Nuclear Sciences, Belgrade (Yugoslavia); Tajima, Toshiki; Sasaki, Akira; Maluckov, A.; Jovanovic, M.

    1998-03-01

    Signatures of Stimulated Raman backscattering of a short-pulse high-intensity laser interacting with an underdense plasma are discussed. We introduce a nonlinear three-wave interaction model that accounts for laser pump depletion and relativistic detuning. A mechanism is revealed based on a generic route to chaos, that predicts a progressive increase of the backscatter complexity with a growing laser intensity. Importance of kinetic effects is outlined and demonstrated in fluid-hybrid and particle simulations. As an application, we show that spectral anomalies of the backscatter, predicted by the above model, are consistent with recent sub-picosecond, high-intensity laser gas-target measurements at Livermore and elsewhere. Finally, a recently proposed scheme for generation of ultra-short, low-prepulse laser pulses by Raman backscattering in a thin foil target, is shown. (author)

  5. High speed, high power one-dimensional beam steering from a 6-element optical phased array.

    Science.gov (United States)

    Huang, W Ronny; Montoya, Juan; Kansky, Jan E; Redmond, Shawn M; Turner, George W; Sanchez-Rubio, Antonio

    2012-07-30

    Beam steering at high speed and high power is demonstrated from a 6-element optical phased array using coherent beam combining (CBC) techniques. The steering speed, defined as the inverse of the time to required to sweep the beam across the steering range, is 40 MHz and the total power is 396 mW. The measured central lobe FWHM width is 565 μrad. High on-axis intensity is maintained periodically by phase-locking the array via a stochastic-parallel-gradient-descent (SPGD) algorithm. A master-oscillator-power-amplifier (MOPA) configuration is used where the amplifier array elements are semiconductor slab-coupled-optical-waveguide-amplifiers (SCOWAs). The beam steering is achieved by LiNbO(3) phase modulators; the phase-locking occurs by current adjustment of the SCOWAs. The system can be readily scaled to GHz steering speed and multiwatt-class output.

  6. DISCUSSION ON DEFECTS DISTRIBUTION NEAR THE STEEL SURFACE IRRADIATED BY INTENSE PULSED ION BEAM

    Institute of Scientific and Technical Information of China (English)

    X.Y.Le; S.Yan; W.J.Zhao; B.X.Han; W.Xiang

    2002-01-01

    The surface defect distribution in stainless steel irradiated with intense pulsed ion beam(IPIB) of current density above 60A/cm2 and acceleration voltage 300-500keV wasdiscussed and analyzed. The defects near the surface of stainless steel were generatedin two ways: (1) generated by the bombardment of energetic ions and (2) induced bythe high level stress near the surface. Thus the temperature and stress distributionsnear the steel surface were calculated by means of our STEIPIB code, which treatedwith the thermal-dynamical process in the target irradiated by the IPIB. Based onthese distributions, the generations and movements of these defects were discussedand compared with the experiment results.

  7. Development and characterization of micro-pattern gas detectors for intense beams of hadrons

    Energy Technology Data Exchange (ETDEWEB)

    Vandenbroucke, Maxence

    2012-07-02

    This thesis work is dedicated to the design, development and characterization of Micro-Pattern Gas Detectors. The performances of a Time Projection Chamber (TPC) equipped with a triple Gas Electron Multiplier (GEM) amplification structure are reported. The intrinsic ion backflow suppression of GEM foils drastically reduces the space charge produced by wire readout in traditional TPC. The GEM solution allows the operation of a TPC at much higher event rate. The second part of this thesis describes the development of a 40 x 40 cm{sup 2} Micromegas detector with a highly segmented central area. A reduction of discharges compared to conventional Micromegas detectors is needed for stable operation in intense beams of hadrons. Spark reduction technologies have been successfully studied and results are presented.

  8. Nonlinear interaction of intense hypergeometric Gaussian subfamily laser beams in plasma

    Science.gov (United States)

    Sobhani, H.; Vaziri (Khamedi), M.; Rooholamininejad, H.; Bahrampour, A. R.

    2016-07-01

    Propagation of Hypergeometric-Gaussian laser beam in a nonlinear plasma medium is investigated by considering the Source Dependent Expansion method. A subfamily of Hypergeometric-Gaussian beams with a non-negative, even and integer radial index, can be expressed as the linear superposition of finite number of Laguerre-Gaussian functions. Propagation of Hypergeometric-Gaussian beams in a nonlinear plasma medium depends on the value of radial index. The bright rings' number of these beams is changed during the propagation in plasma medium. The effect of beam vortex charge number l and initial (input) beam intensity on the self-focusing of Hypergeometric-Gaussian beams is explored. Also, by choosing the suitable initial conditions, Hypergeometric-Gaussian subfamily beams can be converted to one or more mode components that a typical of mode conversion may be occurred. The self-focusing of these winding beams can be used to control the focusing force and improve the electron bunch quality in laser plasma accelerators.

  9. Direct synthesis of the laser beam with pre-determined intensity distribution by means of intracavity beam shaping

    Science.gov (United States)

    Kiyko, Vadim; Vdovin, Gleb; Kislov, Victor; Kondratyev, Vladimir; Ofitserov, Eugeniy

    2014-10-01

    We consider a problem of direct synthesis of the laser beam with predetermined intensity distribution, by means of intracavity adaptive optics. The mathematical formulation of the problem is reduced to the study of the solutions of the resonator equation, expressed in terms of the field amplitudes and phases inside the resonator, and the parameters of resonators that includes the deformable mirror. It is shown that, with some assumptions, the shape of the deformable mirror can be expressed as a function of the output intensity distribution. The results of direct numerical simulations agree with the obtained analytical estimates. Experimental verification is in progress.

  10. CAS - CERN Accelerator School: Intensity Limitations in Particle Beams

    CERN Document Server

    2017-01-01

    AbstractThis report presents the proceedings of a specialized course organized by the CERN Accelerator School (CAS).The topic this time being ’Intensity Limitations in Particle Beams’. The course was held at CERN, Switzerland,from 2-11 November 2015. The last course on this topic was organized in the framework of the Joint US-CERNSchool on Particle Accelerators in November 1990. It was felt that the progress in the field justified a revisedcourse. The lectures addressed fundamental theory as well as experimental results. The indispensable beamdiagnostics and mitigation measures were covered in dedicated lectures. The lectures were complemented byseveral sessions of exercises and the discussion of the solutions.

  11. Electron cloud instability in high intensity proton rings

    Directory of Open Access Journals (Sweden)

    K. Ohmi

    2002-11-01

    Full Text Available An e^{-}p instability has been observed in some proton rings. The instability, which causes beam loss, limits the performance of the ring. The instability may be serious for 3 and 50 GeV proton storage rings in the Japan Proton Accelerator Research Complex (J-PARC. We study the e^{-}p instability in several high intensity proton storage rings operated in the world. This work informs J-PARC of the necessity to cure the instability, for example, by applying a TiN coating on the chamber surface.

  12. Hose Instability and Wake Generation By An Intense Electron Beam in a Self-Ionized Gas

    Energy Technology Data Exchange (ETDEWEB)

    Deng, S.; Barnes, C.D.; Clayton, C.E.; O' Connell, C.; Decker, F.J.; Fonseca, R.A.; Huang, C.; Hogan, M.J.; Iverson, R.; Johnson, D.K.; Joshi, C.; Katsouleas, T.; Krejcik,; Lu, W.; Mori, W.B.; Muggli, P.; Oz, E.; Tsung, F.; Walz, D.; Zhou, M.; /Southern California U. /UCLA /SLAC

    2006-04-12

    The propagation of an intense relativistic electron beam through a gas that is self-ionized by the beam's space charge and wakefields is examined analytically and with 3D particle-in-cell simulations. Instability arises from the coupling between a beam and the offset plasma channel it creates when it is perturbed. The traditional electron hose instability in a preformed plasma is replaced with this slower growth instability depending on the radius of the ionization channel compared to the electron blowout radius. A new regime for hose stable plasma wakefield acceleration is suggested.

  13. Effects of ultra-intense laser driven proton beam on the hydriding property of palladium

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Hiroshi, E-mail: abe.hiroshi10@jaea.go.jp [Environment and Materials Research Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Orimo, Satoshi [Advanced Photon Research Center, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa-shi, Kyoto-fu 619-0215 (Japan); Kishimoto, Masahiko; Aone, Shigeo; Uchida, Hirohisa [Course of Applied Science, Graduate School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Daido, Hiroyuki [Advanced Photon Research Center, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa-shi, Kyoto-fu 619-0215 (Japan); Applied Laser Technology Institute, Tsuruga Head Office, Japan Atomic Energy Agency, Kizaki, Tsuruga-shi, Fukui-ken 914-8585 (Japan); Ohshima, Takeshi [Environment and Materials Research Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2013-07-15

    We investigated the effect of ion irradiation using an ultra-intense laser driven proton beam (UILDPB) method, by which proton beams with energy spectra can be created, on the hydrogen absorption rate of palladium (Pd). The Pd samples were irradiated with proton beams with the maximum energy of 2 MeV and 4 MeV at room temperature. The initial hydrogen absorption rate of Pd was measured before and after proton irradiation. The improvement of the initial hydrogen absorption by the UILDPB irradiation was confirmed.

  14. ARTICLES: Propagation of an intensity-modulated laser beam through a pulsed CO2 amplifier

    Science.gov (United States)

    Fedorov, S. V.; Yur'ev, M. S.

    1987-01-01

    A theoretical study was made (by a self-consistent solution of the equations of vibrational kinetics, hydrodynamics, and quasioptics) of the influence of self-interaction of laser radiation on the transmission of a beam through a CO2 amplifier. It was found that for times exceeding the time for collisional decay of the upper active level the radiation wavefront becomes unstable in the presence of small-scale perturbations of the transverse structure of the beam. It was shown that the harmful influence of the self-interaction on the divergence can be weakened by raising the intensity of the incident beam and the gain of the amplifier.

  15. OTR studies for the high charge CTF3 beam

    CERN Document Server

    Bravin, Enrico; Vermare, C

    2003-01-01

    The CTF3 (CLIC Test Facility 3) will produce 1.56µs long intense electron pulses. The unbunched 5.4A beam of the injector will have a transverse beam size ~1mm. After the buncher the current is reduced to 3.5A and the transverse size varies between a few hundred micrometers and one millimetre along the length of the linac. Calculations indicate that these beam parameters will impose an unbearable thermal load for the intercepting screens currently in use (scintillators and aluminium OTR foils). Graphite and SiC have been investigated as possible alternative materials for the OTR radiators. The possibility of replacing scintillating screens with OTR targets at the low energies of the injector has also been considered. A possible limitation in the use of such high temperature radiators has been identified; ions released from the heated target could focus further the beam with the risk of damaging the target itself and/or blowing up the beam. This would also affect the emittance measurement and would hinder any...

  16. High-intensity, focused ultrasonic fields

    DEFF Research Database (Denmark)

    Jensen, Leif Bjørnø

    1988-01-01

    distribution, etc. involving nonlinearity, diffraction, and absorption in the high-intensity focused ultrasonic fields produced by an ellipsoid as well as a spherical cap focusing geometry. Data from the development of an ESWL of the piezoelectric disk type are reported including demands to transducers...

  17. Approximate kinetic quasiequilibrium distributions for intense beam propagation through a periodic focusing quadrupole lattice

    Directory of Open Access Journals (Sweden)

    Edward A. Startsev

    2010-06-01

    Full Text Available The transverse dynamics of an intense charged particle beam propagating through a periodic quadrupole focusing lattice is described by the nonlinear Vlasov-Maxwell system of equations, where the propagation distances play the role of time. To determine matched-beam quasiequilibrium distribution functions, one needs to determine a dynamical invariant for the beam particles moving in the combined applied and self-generated fields. In this paper, a perturbative Hamiltonian transformation method is developed which is an expansion in the particle’s vacuum phase advance ϵ[over ¯]∼σ_{v}/2π, treated as a small parameter, which is used to transform away the fast particle orbit oscillations and obtain the average Hamiltonian accurate to order ϵ[over ¯]^{3}. The average Hamiltonian is an approximate invariant of the original system, and can be used to determine self-consistent beam quasiequilibrium solutions that are matched to the focusing channel. The equation determining the average self-field potential is derived for general boundary conditions by taking into account the average contribution of the charges induced on the boundary. It is shown for a cylindrical conducting boundary that the average self-field potential acquires an octupole component, which results in the average motion of some beam particles being nonintegrable and their trajectories chaotic. This chaotic behavior of the beam particles may significantly change the nature of the Landau damping (or growth of collective excitations supported by an intense charged particle beam.

  18. Intense positron beam as a source for production of electron-positron plasma

    Science.gov (United States)

    Stoneking, M. R.; Horn-Stanja, J.; Stenson, E. V.; Pedersen, T. Sunn; Saitoh, H.; Hergenhahn, U.; Niemann, H.; Paschkowski, N.; Hugenschmidt, C.; Piochacz, C.

    2016-10-01

    We aim to produce magnetically confined, short Debye length electron-positron plasma and test predicted properties for such systems. A first challenge is obtaining large numbers of positrons; a table-top experiment (system size 5 cm) with a temperature less than 5 eV requires about 1010 positrons to have more than 10 Debye lengths in the system. The NEPOMUC facility at the FRM II research reactor in Germany is one of the world's most intense positron sources. We report on characterization (using a retarding field energy analyzer with magnetic field gradient) of the NEPOMUC beam as delivered to the open beam port at various beam energies and in both the re-moderated and primary beam configurations in order to design optimal trapping (and accumulation) schemes for production of electron-positron plasma. The intensity of the re-moderated (primary) beam is in the range 2 -3 x 107 /s (1 - 5 x 108 /s). The re-moderated beam is currently the most promising for direct injection and confinement experiments; it has a parallel energy spread of 15 - 35% and the transverse energy spread is 6 - 15% of the parallel energy. We report on the implications for injection and trapping in a dipole magnetic field as well as plans for beam development, in situ re-moderation, and accumulation. We also report results demonstrating a difference in phosphor luminescent response to low energy positrons versus electrons.

  19. Propagation characteristics of a high-power broadband laser beam passing through a nonlinear optical medium with defects

    Institute of Scientific and Technical Information of China (English)

    Xueqiong; Chen; Xiaoyan; Li; Ziyang; Chen; Jixiong; Pu; Guowen; Zhang; Jianqiang; Zhu

    2013-01-01

    The intensity distributions of a high-power broadband laser beam passing through a nonlinear optical medium with defects and then propagating in free space are investigated based on the general nonlinear Schr¨odinger equation and the split-step Fourier numerical method. The influences of the bandwidth of the laser beam, the thickness of the medium,and the defects on the light intensity distribution are revealed. We find that the nonlinear optical effect can be suppressed and that the uniformity of the beam can be improved for a high-power broadband laser beam with appropriate wide bandwidth. It is also found that, under the same incident light intensity, a thicker medium will lead to a stronger self-focusing intensity, and that the influence of defects in the optical elements on the intensity is stronger for a narrowband beam than for a broadband beam.

  20. Hybrid simulation of scatter intensity in industrial cone-beam computed tomography

    Science.gov (United States)

    Thierry, R.; Miceli, A.; Hofmann, J.; Flisch, A.; Sennhauser, U.

    2009-01-01

    A cone-beam computed tomography (CT) system using a 450 kV X-ray tube has been developed to challenge the three-dimensional imaging of parts of the automotive industry in short acquisition time. Because the probability of detecting scattered photons is high regarding the energy range and the area of detection, a scattering correction becomes mandatory for generating reliable images with enhanced contrast detectability. In this paper, we present a hybrid simulator for the fast and accurate calculation of the scattering intensity distribution. The full acquisition chain, from the generation of a polyenergetic photon beam, its interaction with the scanned object and the energy deposit in the detector is simulated. Object phantoms can be spatially described in form of voxels, mathematical primitives or CAD models. Uncollided radiation is treated with a ray-tracing method and scattered radiation is split into single and multiple scattering. The single scattering is calculated with a deterministic approach accelerated with a forced detection method. The residual noisy signal is subsequently deconvoluted with the iterative Richardson-Lucy method. Finally the multiple scattering is addressed with a coarse Monte Carlo (MC) simulation. The proposed hybrid method has been validated on aluminium phantoms with varying size and object-to-detector distance, and found in good agreement with the MC code Geant4. The acceleration achieved by the hybrid method over the standard MC on a single projection is approximately of three orders of magnitude.

  1. Benchmark of Space Charge Simulations and Comparison with Experimental Results for High Intensity, Low Energy Accelerators

    CERN Document Server

    Cousineau, Sarah M

    2005-01-01

    Space charge effects are a major contributor to beam halo and emittance growth leading to beam loss in high intensity, low energy accelerators. As future accelerators strive towards unprecedented levels of beam intensity and beam loss control, a more comprehensive understanding of space charge effects is required. A wealth of simulation tools have been developed for modeling beams in linacs and rings, and with the growing availability of high-speed computing systems, computationally expensive problems that were inconceivable a decade ago are now being handled with relative ease. This has opened the field for realistic simulations of space charge effects, including detailed benchmarks with experimental data. A great deal of effort is being focused in this direction, and several recent benchmark studies have produced remarkably successful results. This paper reviews the achievements in space charge benchmarking in the last few years, and discusses the challenges that remain.

  2. Coherent beam combining of high powerfiber lasers: Progress and prospect

    Institute of Scientific and Technical Information of China (English)

    LIU; ZeJin; ZHOU; Pu; XU; XiaoJun; WANG; XiaoLin; MA; YanXing

    2013-01-01

    The recent research progress of coherent beam combining of high power fiber lasers is reviewed. Key technologies like coherently combinable fiber laser, phase control of multiple beams and beam tilling are specially analyzed. Prospects for single coherently combinable high power fiber amplifier, beam tilling and target-in-the-loop control for propagation in real atmosphere are presented.

  3. High-Resolution Energy and Intensity Measurements with CVD Diamond at REX-ISOLDE

    CERN Document Server

    Griesmayer, E; Dobos, D; Wenander, F; Bergoz, J; Bayle, H; Frais-Kölbl, H; Leinweber, J; Aumeyr, T; CERN. Geneva. BE Department

    2009-01-01

    A novel beam instrumentation device for the HIE-REX (High In-tensity and Energy REX) upgrade has been developed and tested at the On-Line Isotope Mass Separator ISOLDE, located at the European Laboratory for Particle Physics (CERN). This device is based on CVD diamond detector technology and is used for measuring the beam intensity, particle counting and measuring the energy spectrum of the beam. An energy resolution of 0.6% was measured at a carbon ion energy of 22.8 MeV. This corresponds to an energy spread of ± 140 keV.

  4. Numerical simulation of a triode source of intense radial converging electron beam

    Science.gov (United States)

    Altsybeyev, V.; Engelko, V.; Ovsyannikov, A.; Ovsyannikov, D.; Ponomarev, V.; Fetzer, R.; Mueller, G.

    2016-10-01

    The results of numerical simulations of a triode source of an intense radial converging electron beam are presented. The role of the initial transverse velocity of electrons, defocusing effect of the controlling grid, the beam self-magnetic field, backscattering of electrons, and ion flow from the target is analyzed. It was found that the ion flow from the target essentially increases the value of the electron current. The influence of the beam self-magnetic field on electron trajectories leads to the fact that there is a critical value of the cathode-grid voltage dividing the mode of the source operation into stable and unstable. The influence of initial transverse electron energies on the beam focusing is essentially higher than the influence of the controlling grid. Backscattering of the beam electrons from the target surface increases the target ion current so that the source operation may become unstable and the distribution of the beam power density on the target becomes nonuniform with a maximum in the center. Electrons passing by the target drift along the source axis. This leads to diminishing the power density at the center of the target and to the exit of peripheral electrons from the source. Conditions for achieving required electron beam parameters (the electron kinetic energy—120 keV, the beam energy density on the target ˜40 J/cm2 on a maximum possible length of the target surface) were determined.

  5. Evaluating the influence of 6 MV and 15 MV photon beams on prostate intensity-modulated radiation therapy plans

    Institute of Scientific and Technical Information of China (English)

    Reham A El Gendy; Ehab M Attalla; Yasser M Elkerm; Ali Alfarrash

    2016-01-01

    Objective We aimed to determine the ef ects of low- and high-energy intensity-modulated radiation therapy (IMRT) photon beams on the target volume planning and on the critical organs in the case of prostate can-cer. Methods Thirty plans were generated by using either 6 MV or 15 MV beams separately, and a combination of both 6 and 15 MV beams. Al plans were generated by using suitable planning objectives and dose con-straints, which were identical across the plans, except the beam energy. The plans were analyzed in terms of their target coverage, conformity, and homogeneity, regardless of the beam energy. Results The mean percentage values of V70 Gy for the rectal wal for the plans with 6 MV, 15 MV, and mixed-energy beams were 16.9%, 17.8%, and 16.4%, respectively, while the mean percentage values of V40 Gy were 53.6%, 52.3%, and 50.4%. The mean dose values to the femoral heads for the 6 MV, 15 MV, and mixed-en-ergy plans were 30.1 Gy, 25.5 Gy, and 25.4 Gy, respectively. The mean integral dose for the 6 MV plans was 10% larger than those for the 15 MV and mixed-energy plans. Conclusion These preliminary results suggest that mixed-energy IMRT plans may be advantageous with respect to the dosimetric characteristics of low- and high-energy beams. Although the reduction of dose to the organs at risk may not be clinical y relevant, in this study, IMRT plans using mixed-energy beams exhibited better OAR sparing and overal higher plan quality for deep-seated tumors.

  6. Evaluation of ultra-fine grained tungsten under transient high heat flux by high-intensity pulsed ion beam%强流脉冲离子束作用下超细晶钨的抗瞬态热负荷性能评价

    Institute of Scientific and Technical Information of China (English)

    谈军; 周张健; 朱小鹏; 郭双全; 屈丹丹; 雷明凯; 葛昌纯

    2012-01-01

    采用高能球磨和放电等离子体烧结技术制备纯钨、氧化物弥散强化钨和碳化物弥散强化钨.为了评价钨在瞬态热冲击下的性能,采用强流脉冲离子束,在热流密度高达160 MW/(m2·s-1/2)的条件下对4种不同晶粒尺寸的钨进行抗热冲击试验.与商品钨相比,弥散强化钨在瞬态高热流作用下显现出不同的行为.氧化物弥散强化钨显现出较差的抗热冲击性能,这主要是由于低熔点的第二相Ti和Y2O3的引入,从而使得钨的表面发生熔融、起泡和开裂.而碳化物弥散强化钨合金则显现出较好的抗热冲击性能.%Pure tungsten,oxide dispersion strengthened tungsten and carbide dispersion strengthened tungsten were fabricated by high-energy ball milling and spark plasma sintering process.In order to evaluate the properties of the tungsten alloys under transient high heat flues,four tungsten samples with different grain sizes were tested by high-intensity pulsed ion beam with a heat flux as high as 160 MW/(m2·s-1/2).Compared with the commercial tungsten,the surface modification of the oxide dispersion strengthened tungsten by high-intensity pulsed ion beam is completely different.The oxide dispersion strengthened tungsten shows inferior thermal shock response due to the low melting point second phase of Ti and Y2O3,which results in the surface melting,boiling bubbles and cracking.While the carbide dispersion strengthened tungsten shows better thermal shock response than the commercial tungsten.

  7. Interaction of High Intensity Electromagnetic Waves with Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    G. Shvets

    2008-10-03

    The focus of our work during the duration of this grant was on the following areas: (a) the fundamental plasma physics of intense laser-plasma interactions, including the nonlinear excitation of plasma waves for accelerator applications, as well as the recently discovered by us phenomenon of the relativistic bi-stability of relativistic plasma waves driven by a laser beatwave; (b) interaction of high power microwave beams with magnetized plasma, including some of the recently discovered by us phenomena such as the Undulator Induced Transparency (UIT) as well as the new approaches to dynamic manipulation of microwave pulses; (c) investigations of the multi-color laser pulse interactions in the plasma, including the recently discovered by us phenomenon of Electromagnetic Cascading (EC) and the effect of the EC of three-dimensional dynamics of laser pulses (enhanced/suppressed selffocusing etc.); (d) interaction of high-current electron beams with the ambient plasma in the context of Fast Ignitor (FI) physics, with the emphasis on the nonlinear dynamics of the Weibel instability and beam filamentation.

  8. Investigation of the effects of intense pulsed particle beams on the durability of metal-to-plastic interfaces.

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Somuri V.; Renk, Timothy J.; Provencio, Paula Polyak; Petersen, Donald W. (University of Alabama, Birmingham, AL); Petersen, Thomas D. (University of California, San Diego, CA); Buchheit, Thomas Edward; McNulty, Donald E. (DePuy Orthopaedic, Inc., Warsaw, IN); Engelko, Vladimir (D. V. Efremov Scientific Research Institute of the Electrophysical Apparatus, St. Petersburg, Russia)

    2005-02-01

    We have investigated the potential for intense particle beam surface modification to improve the mechanical properties of materials commonly used in the human body for contact surfaces in, for example, hip and knee implants. The materials studied include Ultra-High Molecular Weight Polyethylene (UHMWPE), Ti-6Al-4Al (titanium alloy), and Co-Cr-Mo alloy. Samples in flat form were exposed to both ion and electron beams (UHMWPE), and to ion beam treatment (metals). Post-analysis indicated a degradation in bulk properties of the UHMWPE, except in the case of the lightest ion fluence tested. A surface-alloyed Hf/Ti layer on the Ti-6Al-4V is found to improve surface wear durability, and have favorable biocompatibility. A promising nanolaminate ceramic coating is applied to the Co-Cr-Mo to improve surface hardness.

  9. Beam brilliance investigation of high current ion beams at GSI heavy ion accelerator facility

    Energy Technology Data Exchange (ETDEWEB)

    Adonin, A. A., E-mail: a.adonin@gsi.de; Hollinger, R. [Linac and Operations/Ion Sources, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt (Germany)

    2014-02-15

    In this work the emittance measurements of high current Ta-beam provided by VARIS (Vacuum Arc Ion Source) ion source are presented. Beam brilliance as a function of beam aperture at various extraction conditions is investigated. Influence of electrostatic ion beam compression in post acceleration gap on the beam quality is discussed. Use of different extraction systems (single aperture, 7 holes, and 13 holes) in order to achieve more peaked beam core is considered. The possible ways to increase the beam brilliance are discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-04-09

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

  11. Formation of a high intensity low energy positron string

    Science.gov (United States)

    Donets, E. D.; Donets, E. E.; Syresin, E. M.; Itahashi, T.; Dubinov, A. E.

    2004-05-01

    The possibility of a high intensity low energy positron beam production is discussed. The proposed Positron String Trap (PST) is based on the principles and technology of the Electron String Ion Source (ESIS) developed in JINR during the last decade. A linear version of ESIS has been used successfully for the production of intense highly charged ion beams of various elements. Now the Tubular Electron String Ion Source (TESIS) concept is under study and this opens really new promising possibilities in physics and technology. In this report, we discuss the application of the tubular-type trap for the storage of positrons cooled to the cryogenic temperatures of 0.05 meV. It is intended that the positron flux at the energy of 1-5 eV, produced by the external source, is injected into the Tubular Positron Trap which has a similar construction as the TESIS. Then the low energy positrons are captured in the PST Penning trap and are cooled down because of their synchrotron radiation in the strong (5-10 T) applied magnetic field. It is expected that the proposed PST should permit storing and cooling to cryogenic temperature of up to 5×109 positrons. The accumulated cooled positrons can be used further for various physics applications, for example, antihydrogen production.

  12. Double beam near-infrared spectrometer for compensation of background water absorption and instrumental drift in intensity

    Institute of Scientific and Technical Information of China (English)

    CHANG Min; PENG Dan; XU Ke-xin

    2007-01-01

    A double beam near-infrared spectrometer is developed to compensate the water absorption and instrumental drift in intensity. The spectrometer maybe used for both single and double beam measurements, and the two operation modes are compared. The results show that the double beam technique eliminates instrumental drift in the single beam measurement and therefore the stability of the system increases by more than 20%. The compensation of the double beam system on water absorption is verified by the measurement of fat content in milk. The results show that the spectrum data based on double beam mode get better calibration model and lower prediction error than traditional single beam mode.

  13. Adapting High Brightness Relativistic Electron Beams for Ultrafast Science

    Science.gov (United States)

    Scoby, Cheyne Matthew

    This thesis explores the use of ultrashort bunches generated by a radiofrequency electron photoinjector driven by a femtosecond laser. Rf photoinjector technology has been developed to generate ultra high brightness beams for advanced accelerators and to drive advanced light source applications. The extremely good quality of the beams generated by this source has played a key role in the development of 4th generation light sources such as the Linac Coherent Light Source, thus opening the way to studies of materials science and biological systems with high temporal and spatial resolution. At the Pegasus Photoinjector Lab, we have developed the application of a BNL/SLAC/UCLA 1.6-cell rf photoinjector as a tool for ultrafast science in its own right. It is the aim of this work to explore the generation of ultrashort electron bunches, give descriptions of the novel ultrafast diagnostics developed to be able to characterize the electron bunch and synchronize it with a pump laser, and share some of the scientific results that were obtained with this technology at the UCLA Pegasus laboratory. This dissertation explains the requirements of the drive laser source and describes the principles of rf photoinjector design and operation necessary to produce electron bunches with an rms longitudinal length < 100 femtoseconds containing 107 - 108 electrons per bunch. In this condition, when the laser intensity is sufficiently high, multiphoton photoemission is demonstrated to be more efficient in terms of charge yield than single photon photoemission. When a short laser pulse hits the cathode the resulting beam dynamics are dominated by a strong space charge driven longitudinal expansion which leads to the creation of a nearly ideal uniformly filled ellipsoidal distribution. These beam distributions are characterized by linear space charge forces and hence by high peak brightness and small transverse emittances. This regime of operation of the RF photoinjector is also termed the

  14. Review of intense-ion-beam propagation with a view toward measuring ion energy

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M.

    1982-08-25

    The subject of this review is intense ion beam propagation and the possibilities of measuring time dependent ion energy in the beam. Propagation effects discussed include charge separation, charge and current autoneutralization, electron thermalization and current neutralization decay. The interaction of a plasma beam with material obstacles, like collimators, and with transverse magnetic fields is also described. Depending on beam energy, density and pulse length, these interactions can include material ablation with plasmadynamic flow and undeflected propagation across transverse magnetic fields by a polarization drift. On the basis of this review I conclude that three diagnostics: a single floating potential probe, net current probes (Faraday cups) and a Rutherford scattering spectrometer appear capable of giving prompt, time dependent ion energy measurements.

  15. Enhanced proton beam collimation in the ultra-intense short pulse regime

    Science.gov (United States)

    Green, J. S.; Dover, N. P.; Borghesi, M.; Brenner, C. M.; Cameron, F. H.; Carroll, D. C.; Foster, P. S.; Gallegos, P.; Gregori, G.; McKenna, P.; Murphy, C. D.; Najmudin, Z.; Palmer, C. A. J.; Prasad, R.; Romagnani, L.; Quinn, K. E.; Schreiber, J.; Streeter, M. J. V.; Ter-Avetisyan, S.; Tresca, O.; Zepf, M.; Neely, D.

    2014-08-01

    The collimation of proton beams accelerated during ultra-intense laser irradiation of thin aluminum foils was measured experimentally whilst varying laser contrast. Increasing the laser contrast using a double plasma mirror system resulted in a marked decrease in proton beam divergence (20° to <10°), and the enhanced collimation persisted over a wide range of target thicknesses (50 nm-6 µm), with an increased flux towards thinner targets. Supported by numerical simulation, the larger beam divergence at low contrast is attributed to the presence of a significant plasma scale length on the target front surface. This alters the fast electron generation and injection into the target, affecting the resultant sheath distribution and dynamics at the rear target surface. This result demonstrates that careful control of the laser contrast will be important for future laser-driven ion applications in which control of beam divergence is crucial.

  16. The Magnetic Model of the LHC during Commissioning to higher Beam Intensities in 2010-2011

    CERN Document Server

    Deniau, L; Fiscarelli, L; Giovannozzi, M; Hagen, P; Lamont, M; Montenero, G; Steinhagen, R; Strzelczyk, M; Todesco, E; Tomas, R; Venturini Delsolaro, W; Wenninger, J

    2011-01-01

    The Field Description of the Large Hadron Collider (FiDeL) model is a set of semi-empirical equations linking the magnets behaviours established from magnetic measurements to the magnetic properties of the machine observed through beam measurements. The FiDeL model includes the parameterization of static and dynamic (time dependent) components. In the present paper, we outline the relationship between the beam observables (orbit, tune, chromaticity) and the model components during the commissioning to higher beam intensities in 2010-2011, with energy of 3.5 TeV per beam. The main relevant issues are (i) the operation at 10 A/s ramp rate and their influence on chromatic correction, (ii) the beta beating and its relation to the quadrupoles transfer functions and (iii) the origin of the observed tune decay at injection.

  17. Nonlinear dynamics and bifurcation mechanisms in intense electron beam with virtual cathode

    Science.gov (United States)

    Frolov, Nikita S.; Kurkin, Semen A.; Koronovskii, Alexey A.; Hramov, Alexander E.

    2017-07-01

    In this paper we report on the results of investigations of nonlinear dynamics and bifurcation mechanisms in intense electron beam with virtual cathode in micrometer-scaled source of sub-THz electromagnetic radiation. The numerical analysis is provided by means of 3D electromagnetic particle-in-cell (PIC) simulation. We have studied evolution of the system dynamics with the change of beam current value by means of Fourier and bifurcation analysis. The bifurcation diagram has identified a number of the alternating regions of beam current with regular or chaotic regimes of system dynamics. The study of spatiotemporal dynamics of formed electron structures in the beam has revealed the physical mechanisms responsible for the regimes switchings in the system.

  18. Design method for automotive high-beam LED optics

    Science.gov (United States)

    Byzov, Egor V.; Moiseev, Mikhail A.; Doskolovich, Leonid L.; Kazanskiy, Nikolay L.

    2015-09-01

    New analytical method for the calculation of the LED secondary optics for automotive high-beam lamps is presented. Automotive headlamps should illuminate the road and the curb at the distance of 100-150 meters and create a bright, flat, relatively powerful light beam. To generate intensity distribution of this kind we propose to use TIR optical element (collimator working on the total internal reflection principle) with array of microlenses (optical corrector) on the upper surface. TIR part of the optical element enables reflection of the side rays to the front direction and provides a collimated beam which incidents on the microrelief. Microrelief, in its turn, dissipates the light flux in horizontal direction to meet the requirements of the Regulations 112, 113 and to provide well-illuminated area across the road in the far field. As an example, we computed and simulated the optical element with the diameter of 33 millimeters and the height of 22 millimeters. Simulation data shows that three illuminating modules including Cree XP-G2 LED and lens allow generating an appropriate intensity distribution for the class D of UNECE Regulations.

  19. Single-pulse and multipulse longitudinal phase space and temperature measurements of an intense ion beam

    Science.gov (United States)

    Coleman, J. E.; Seidl, P. A.; Bieniosek, F. M.; Leitner, M. A.; Lidia, S. M.; Vay, J. L.; Waldron, W. L.; Grote, D. P.; Welch, D. R.

    2012-07-01

    Longitudinal phase space and temperature measurements were conducted on a 2-3μs long, singly charged K+ ion bunch with an ion energy of ˜0.3MeV and current of 30 mA. The principal objective of these experiments was to measure the longitudinal beam dynamics and study the limits of axial compression. The differences between the measured beam energy, longitudinal beam dynamics, and the amplitude and time history of the Marx voltage waveform were all quantified. Longitudinal phase space measurements indicate a slight chromaticity (<1%) in the beam from head to tail. Record low longitudinal temperatures of Tz=2-4×10-2eV were measured for a beam bunch of this intensity with negligible effects from neutralizing the beam space charge with a background plasma. A qualitative comparison of experimental and calculated results are presented, which include time resolved longitudinal distributions, and phase space of the beam at 430 cm.

  20. Small signal gain based on analytic models of thin intense electron beams

    Science.gov (United States)

    James Elliott, C.; McVey, Brian; Schmitt, Mark

    1991-07-01

    We develop the free electron laser theory of the effective energy distribution and the small signal gain for a thin electron beam. The assumption of thinness allows us to treat various transverse locations and electron beam trajectory angles as introducing phase shifts that have the same effect as those introduced by a change in energy of the electron. These ideas extend previous work of Colson et al., Dattoli et al., Scharlemann, and others in five important ways. The first is the ability to treat electron beams with three different classes of matching or symmetry conditions: (i) electron beams with separate betatron matching in each plane. (ii) those with aspect ratio matching, and (iii) crossed matched beams. Manifestations of these symmetries include elliptical cross-sections and electron beams that have modulated spatial profiles. For these we derive analytical expressions for effective energy distributions. Second, two emittance parameters for the electron beam are shown to consolidate into a single parameter that describes most of the energy variation of the effective energy distributions. Thus, the effective energy distribution for a 1:4 ribbon electron beam is nearly equivalent to a distribution for a beam of circular cross-section. Third, these calculations extend to energy distributions, angular distributions, and spatial distributions that all follow Gaussian profiles. Fourth, this model incorporates the description of the incident Gaussian optical beam and the above electron beam dynamics into a single influence function kernel. Emittance, energy spread, diffraction, and gain may be interpreted as limiting the length over which the bunching contributions of the propagating electric fields downstream are important. Fifth, three-dimensional profiles of the optical fields are computed. This work is complementary to the recent work of Yu, Krinsky and Gluckstern in that ours always describes the transition from low gain to high gain for a thin beam and not

  1. Classically entangled optical beams for high-speed kinematic sensing

    CERN Document Server

    Berg-Johansen, Stefan; Stiller, Birgit; Banzer, Peter; Ornigotti, Marco; Giacobino, Elisabeth; Leuchs, Gerd; Aiello, Andrea; Marquardt, Christoph

    2015-01-01

    Tracking the kinematics of fast-moving objects is an important diagnostic tool for science and engineering. Existing optical methods include high-speed CCD/CMOS imaging, streak cameras, lidar, serial time-encoded imaging and sequentially timed all-optical mapping. Here, we demonstrate an entirely new approach to positional and directional sensing based on the concept of classical entanglement in vector beams of light. The measurement principle relies on the intrinsic correlations existing in such beams between transverse spatial modes and polarization. The latter can be determined from intensity measurements with only a few fast photodiodes, greatly outperforming the bandwidth of current CCD/CMOS devices. In this way, our setup enables two-dimensional real-time sensing with temporal resolution in the GHz range. We expect the concept to open up new directions in photonics-based metrology and sensing.

  2. Electroweak interactions between intense neutrino beams and dense electron-positron magneto-plasmas

    CERN Document Server

    Tsintsadze, N L; Stenflo, L

    2003-01-01

    The electroweak coupling between intense neutrino beams and strongly degenerate relativistic dense electron-positron magneto-plasmas is considered. The intense neutrino bursts interact with the plasma due to the weak Fermi interaction force, and their dynamics is governed by a kinetic equation. Our objective here is to develop a kinetic equation for a degenerate neutrino gas and to use that equation to derive relativistic magnetohydrodynamic equations. The latter are useful for studying numerous collective processes when intense neutrino beams nonlinearly interact with degenerate, relativistic, dense electron-positron plasmas in strong magnetic fields. If the number densities of the plasma particles are of the order of 10 sup 3 sup 3 cm sup - sup 3 , the pair plasma becomes ultra-relativistic, which strongly affects the potential energy of the weak Fermi interaction. The new system of equations allows several neutrino-driven streaming instabilities involving new types of relativistic Alfven-like waves, The re...

  3. High electron beam dosimetry using ZrO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Lueza M, F.; Rivera M, T. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, IPN, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Azorin N, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Garcia H, M. [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2009-10-15

    This paper reports the experimental results of studying the thermoluminescent (Tl) properties of ZrO{sub 2} powder embedded in polytetrafluorethylene (PTFE) exposed to high energy electron beam from linear accelerators (Linac). Structural and morphological characteristics were also reported. Irradiations were conducted using high energy electrons beams in the range from 2 to 18 MeV. Pellets of ZrO{sub 2}+PTFE were produced using polycrystalline powder grown by the precipitation method. These pellets presented a Tl glow curve exhibiting an intense glow peak centered at around 235 C. Tl response as a function of high electron absorbed dose was linear in the range from 2 to 30 Gy. Repeatability determined by exposing a set of pellets repeatedly to the same electron absorbed dose was 0.5%. Fading along 30 days was about 50%. Then, results obtained in this study suggest than ZrO{sub 2}+PTFE pellets could be used for high energy electron beam dosimetry provided fading correction is accounted for. (Author)

  4. Production of High-Intensity, Highly Charged Ions

    CERN Document Server

    Gammino, S

    2013-01-01

    In the past three decades, the development of nuclear physics facilities for fundamental and applied science purposes has required an increasing current of multicharged ion beams. Multiple ionization implies the formation of dense and energetic plasmas, which, in turn, requires specific plasma trapping configurations. Two types of ion source have been able to produce very high charge states in a reliable and reproducible way: electron beam ion sources (EBIS) and electron cyclotron resonance ion sources (ECRIS). Multiple ionization is also obtained in laser-generated plasmas (laser ion sources (LIS)), where the high-energy electrons and the extremely high electron density allow step-by-step ionization, but the reproducibility is poor. This chapter discusses the atomic physics background at the basis of the production of highly charged ions and describes the scientific and technological features of the most advanced ion sources. Particular attention is paid to ECRIS and the latest developments, since they now r...

  5. Intense ${^31-35}$Ar beams produced with a nanostructured CaO target at ISOLDE

    CERN Document Server

    Ramos, J P; Mendonça, T M; Seiffert, C; Senos, A M R; Fynbo, H O U; Tengblad, O; Briz, J A; Lund, M V; Koldste, G T; Carmona-Gallardo, M; Pesudo, V; Stora, T

    2014-01-01

    At the ISOLDE facility at CERN, thick targets are bombarded with highly energetic pulsed protons to produce radioactive ion beams (RIBs). The isotopes produced in the bulk of the material have to diffuse out of the grain and effuse throughout the porosity of the material to a transfer line which is connected to an ionizer, from which the charged isotopes are extracted and delivered for physics experiments. Calcium oxide (CaO) powder targets have been used to produce mainly neutron deficient argon and carbon RIBs over the past decades. Such targets presented unstable yields, either decaying over time or low from the beginning of operation. These problems were suspected to come from the degradation of the target microstructure (sintering due to high temperature and/or high proton intensity). In this work, a CaO microstructural study in terms of sintering was conducted on a nanostructured CaO powder synthesized from the respective carbonate. Taking the results of this study, several changes were made at ISOLDE i...

  6. Early Beam Injection Scheme for the Fermilab Booster: A Path for Intensity Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, C. M. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-10-28

    Over the past decade, Fermilab has focused efforts on the intensity frontier physics and is committed to increase the average beam power delivered to the neutrino and muon programs substantially. Many upgrades to the existing injector accelerators, namely, the current 400 MeV LINAC and the Booster, are in progress under the Proton Improvement Plan (PIP). Proton Improvement Plan-II (PIP-II) proposes to replace the existing 400 MeV LINAC by a new 800 MeV LINAC, as an injector to the Booster which will increase Booster output power by nearly a factor of two from the PIP design value by the end of its completion. In any case, the Fermilab Booster is going to play a very significant role for nearly next two decades. In this context, I have developed and investigated a new beam injection scheme called "early injection scheme" (EIS) for the Booster with the goal to significantly increase the beam intensity output from the Booster thereby increasing the beam power to the HEP experiments even before PIP-II era. The scheme, if implemented, will also help improve the slip-stacking efficiency in the MI/RR. Here I present results from recent simulations, beam studies, current status and future plans for the new scheme.

  7. Beam manipulation techniques, nonlinear beam dynamics, and space charge effect in high energy high power accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S. Y.

    2014-04-07

    We had carried out a design of an ultimate storage ring with beam emittance less than 10 picometer for the feasibility of coherent light source at X-ray wavelength. The accelerator has an inherent small dynamic aperture. We study method to improve the dynamic aperture and collective instability for an ultimate storage ring. Beam measurement and accelerator modeling are an integral part of accelerator physics. We develop the independent component analysis (ICA) and the orbit response matrix method for improving accelerator reliability and performance. In collaboration with scientists in National Laboratories, we also carry out experimental and theoretical studies on beam dynamics. Our proposed research topics are relevant to nuclear and particle physics using high brightness particle and photon beams.

  8. Hot electron generation and energy coupling in planar experiments with shock ignition high intensity lasers

    Science.gov (United States)

    Wei, M. S.; Krauland, C.; Alexander, N.; Zhang, S.; Peebles, J.; Beg, F. N.; Theobald, W.; Borwick, E.; Ren, C.; Yan, R.; Haberberger, D.; Betti, R.; Campbell, E. M.

    2016-10-01

    Hot electrons produced in nonlinear laser plasma interactions are critical issues for shock ignition (SI) laser fusion. We conducted planar target experiments to characterize hot electron and energy coupling using the high energy OMEGA EP laser system at SI high intensities. Targets were multilayered foils consisting of an ablator (either plastic or lithium) and a Cu layer to facilitate hot electron detection via fluorescence and bremsstrahlung measurements. The target was first irradiated by multi-kJ, low-intensity UV beams to produce a SI-relevant mm-scale hot ( 1 keV) preformed plasma. The main interaction pulse, either a kJ 1-ns UV pulse with intensity 1.6x1016 Wcm-2 or a kJ 0.1-ns IR pulse with intensity up to 2x1017 Wcm-2was injected at varied timing delays. The high intensity IR beam was found to strongly interact with underdense plasmas breaking into many filaments near the quarter critical density region followed by propagation of those filaments to critical density, producing hot electrons with Thot 70 keV in a well-contained beam. While the high intensity UV beam showed poor energy coupling. Details of the experiments and the complementary PIC modeling results will be presented. Work supported by U.S. DOE under contracts DE-NA0002730 (NLUF) and DE-SC0014666 (HEDLP).

  9. X-ray spectral determination by successive modifications of the beam intensity

    Energy Technology Data Exchange (ETDEWEB)

    Mainardi, R.T.; Barrea, R.A. (Universidad Nacional de Cordoba (Argentina). Facultad de Matematica, Astronomia y Fisica)

    1989-08-10

    A simple and practical indirect method to determine spectra from X-ray tubes has been developed on the basis of successive modifications of beam flux. The beam is either scattered at different angles or attenuated by metal foils and the intensity is measured by an ionization chamber. The data are analyzed by means of an interative program that solves a system of equations whose unknowns define a parametric fit of the X-ray spectrum. We have checked this method with simulated measurements of tabulated spectra, as well as with our own measurements on available X-ray apparatus and for several different applied voltages. (orig.).

  10. Scattering from a Multi-Layered Sphere Located in a High-Order Hermite-Gaussian Beam

    Institute of Scientific and Technical Information of China (English)

    LI Hai-Ying; WU Zhen-Sen; LI Zheng-Jun

    2009-01-01

    Scattering of a high-order Hermite-Gaussian beam by a multi-layered sphere is analyzed.The incident highorder Hermite-Gaussian beam field is expressed by the complex-source-point method and expanded in terms of spherical vector wave functions.The beam shape coefficients of the Hermite-Gaussian beam are obtained.Under electromagnetic field boundary conditions, coefficients is the expressions of scattering fields are derived.Results of the numerical calculation of scattering intensity axe presented.The effects of the particle parameters and beam parameters on scattering intensity are discussed in detail.

  11. Upgrades to the SPS-to-LHC Transfer Line Beam Stoppers for the LHC High-Luminosity Era

    CERN Document Server

    Kain, Verena; Fraser, Matthew; Goddard, Brennan; Meddahi, Malika; Perillo Marcone, Antonio; Steele, Genevieve; Velotti, Francesco

    2016-01-01

    Each of the 3 km long transfer lines between the SPS and the LHC is equipped with two beam stoppers (TEDs), one at the beginning of the line and one close to the LHC injection point, which need to absorb the full transferred beam. The beam stoppers are used for setting up the SPS extractions and transfer lines with beam without having to inject into the LHC. Energy deposition and thermo-mechanical simulations have, however, shown that the TEDs will not be robust enough to safely absorb the high intensity beams foreseen for the high-luminosity LHC era. This paper will summarize the simulation results and limitations for upgrading the beam stoppers. An outline of the hardware upgrade strategy for the TEDs together with modifications to the SPS extraction interlock system to enforce intensity limitations for beam on the beam stoppers will be given.

  12. Predictability of bone density at posterior mandibular implant sites using cone-beam computed tomography intensity values.

    Science.gov (United States)

    Alkhader, Mustafa; Hudieb, Malik; Khader, Yousef

    2017-01-01

    The aim of this study was to investigate the predictability of bone density at posterior mandibular implant sites using cone-beam computed tomography (CBCT) intensity values. CBCT cross-sectional images for 436 posterior mandibular implant sites were selected for the study. Using Invivo software (Anatomage, San Jose, California, USA), two observers classified the bone density into three categories: low, intermediate, and high, and CBCT intensity values were generated. Based on the consensus of the two observers, 15.6% of sites were of low bone density, 47.9% were of intermediate density, and 36.5% were of high density. Receiver-operating characteristic analysis showed that CBCT intensity values had a high predictive power for predicting high density sites (area under the curve [AUC] =0.94, P density sites (AUC = 0.81, P density sites was 218 (sensitivity = 0.77 and specificity = 0.76) and the best cut-off value for intensity to predict high density sites was 403 (sensitivity = 0.93 and specificity = 0.77). CBCT intensity values are considered useful for predicting bone density at posterior mandibular implant sites.

  13. High current precision long pulse electron beam position monitor

    CERN Document Server

    Nelson, S D; Fessenden, T J; Holmes, C

    2000-01-01

    Precision high current long pulse electron beam position monitoring has typically experienced problems with high Q sensors, sensors damped to the point of lack of precision, or sensors that interact substantially with any beam halo thus obscuring the desired signal. As part of the effort to develop a multi-axis electron beam transport system using transverse electromagnetic stripline kicker technology, it is necessary to precisely determine the position and extent of long high energy beams for accurate beam position control (6 - 40 MeV, 1 - 4 kA, 2 μs beam pulse, sub millimeter beam position accuracy.) The kicker positioning system utilizes shot-to-shot adjustments for reduction of relatively slow (< 20 MHz) motion of the beam centroid. The electron beams passing through the diagnostic systems have the potential for large halo effects that tend to corrupt position measurements.

  14. Determination of intensity and position of the extracted electron beam at ELSA by means of high-frequency resonators; Bestimmung von Intensitaet und Position des extrahierten Elektronenstrahls an ELSA mittels Hochfrequenzresonatoren

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, Thorsten

    2012-06-15

    The electron stretcher facility ELSA provides an electron beam of a few hundred pA used for the generation of bremsstrahlung photons probing the nucleon structure in a detector setup. For the correct interpretation of the events registered, the persistence of the beam position over time is crucial. Its continuous monitoring has been enabled by setting up a measurement system based on resonant cavities. Position signals at a frequency of 1.5 GHz and below one aW of power can be abstracted from the beam without degrading its quality. After frequency down-conversion to a few kHz, a narrow bandwidth detection performed by lock-in amplifiers separates them from noise. A maximum sample rate of 9 Hz and a resolution of one tenth of a millimeter could be achieved. The position signals have to be normalized to the beam current which is monitored by another dedicated resonator. The measurement precision down to a few pA allows for the accelerator extraction mechanism to be controlled by a feedback loop in order to obtain the respective requested current. (orig.)

  15. Use of radial self-field geometry for intense pulsed ion beam generation above 6 MeV on Hermes III.

    Energy Technology Data Exchange (ETDEWEB)

    Renk, Timothy Jerome [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Harper-Slaboszewicz, Victor Jozef [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ginn, William Craig [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mikkelson, Kenneth A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schall, Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cooper, Gary Wayne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2012-12-01

    We investigate the generation and propagation of intense pulsed ion beams at the 6 MeV level and above using the Hermes III facility at Sandia National Laboratories. While high-power ion beams have previously been produced using Hermes III, we have conducted systematic studies of several ion diode geometries for the purpose of maximizing focused ion energy for a number of applications. A self-field axial-gap diode of the pinch reflex type and operated in positive polarity yielded beam power below predicted levels. This is ascribed both to power flow losses of unknown origin upstream of the diode load in Hermes positive polarity operation, and to anomalies in beam focusing in this configuration. A change to a radial self-field geometry and negative polarity operation resulted in greatly increased beam voltage (> 6 MeV) and estimated ion current. A comprehensive diagnostic set was developed to characterize beam performance, including both time-dependent and time-integrated measurements of local and total beam power. A substantial high-energy ion population was identified propagating in reverse direction, i.e. from the back side of the anode in the electron beam dump. While significant progress was made in increasing beam power, further improvements in assessing the beam focusing envelope will be required before ultimate ion generation efficiency with this geometry can be completely determined.

  16. Long- and short-term average intensity for multi-Gaussian beam with a common axis in turbulence

    Institute of Scientific and Technical Information of China (English)

    Chu Xiu-xiang

    2011-01-01

    With the help of the extended Huygens-Fresnel principle and the short-term mutual coherence function, the analytical formula of short-term average intensity for multi-Gaussian beam (MGB) in the turbulent atmosphere has been derived. The intensity in the absence of turbulence and the long-term average intensity in turbulence can both also be expressed in this formula. As special cases, comparisons among short-term average intensity, long-term average intensity, and the intensity in the absence of turbulence for fiat topped beam and annular beam are carried out. The effects of the order of MGB, propagation distance and aperture radius on beam spreading are analysed and discussed in detail.

  17. Ion injection optimization for a linear Paul trap to study intense beam propagation

    Directory of Open Access Journals (Sweden)

    Moses Chung

    2007-01-01

    Full Text Available The Paul Trap Simulator Experiment (PTSX is a linear Paul trap whose purpose is to simulate the nonlinear transverse dynamics of intense charged particle beam propagation in periodic-focusing quadrupole magnetic transport systems. Externally created cesium ions are injected and trapped in the long central electrodes of the PTSX device. In order to have well-matched one-component plasma equilibria for various beam physics experiments, it is important to optimize the ion injection. From the experimental studies reported in this paper, it is found that the injection process can be optimized by minimizing the beam mismatch between the source and the focusing lattice, and by minimizing the number of particles present in the vicinity of the injection electrodes when the injection electrodes are switched from the fully oscillating voltage waveform to their static trapping voltage.

  18. Small-Scale Self-Focusing of Intense Laser Beams In the Presence of Vector Effect

    Institute of Scientific and Technical Information of China (English)

    WEN Shuang-Chun; FAN Dian-Yuan

    2000-01-01

    We extend Bespalov-Talanov (B-T) theory on small-scale self-focusing (SSSF) to include vector effect of a very narrow intense laser beam with application of the vector self-focusing model. The gain spectrum for perturbations is obtained by using the standard linear instability analysis. It is shown that the influence on SSSF of vector effect is closely related to the beam width. For a very narrow beam, the role played by vector effect becomes significant, it reduces the fastest growing frequency and the maximum growth rate, and shortens the frequency range for perturbation growing, and thus deviates the gain spectrum from that of B-T theory.

  19. Rapid Melt and Resolidification of Surface Layers Using Intense, Pulsed Ion Beams Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Renk, Timothy J.

    1998-10-02

    The emerging technology of pulsed intense ion beams has been shown to lead to improvements in surface characteristics such as hardness and wear resistance, as well as mechanical smoothing. We report hereon the use of this technology to systematically study improvements to three types of metal alloys - aluminum, iron, and titanium. Ion beam tieatment produces a rapid melt and resolidification (RMR) of the surface layer. In the case of a predeposited thin-fihn layer, the beam mixes this layer into the substrate, Ieading to improvements that can exceed those produced by treatment of the alloy alone, In either case, RMR results in both crystal refinement and metastable state formation in the treated surface layer not accessible by conventional alloy production. Although more characterization is needed, we have begun the process of relating these microstructural changes to the surface improvements we discuss in this report.

  20. Upgrade of the Fast Beam Intensity Measurement System for the CERN PS Complex

    CERN Document Server

    Allica, JC; Andreazza, W; Belohrad, D; Favre, G; Favre, N; Jensen, L; Lenardon, F; Vollenberg, W

    2014-01-01

    The CERN Proton Synchrotron complex (CPS) has been operational for over 50 years. During this time the Fast Beam Current Transformers (FBCTs) have only been repaired when they ceased to function, or individually modified to cope with new requests. This strategy resulted in a large variation of designs, making their maintenance difficult and limiting the precision with which comparisons could be made between transformers for the measurement of beam intensity transmission. During the first long shutdown of the CERN LHC and its injectors (LS1) these systems have undergone a major consolidation, with detectors and acquisition electronics upgraded to provide a uniform measurement system throughout the PS complex. This paper discusses the solutions used and analyses the first beam measurement results.

  1. Design concept of radiation control system for the high intensity proton accelerator facility

    CERN Document Server

    Miyamoto, Y; Harada, Y; Ikeno, K

    2002-01-01

    Description is given for the characteristic radiation environment for the High Intensity Proton Accelerator Facility and the design concept of the radiation control system of it. The facility is a large scale accelerator complex consisting of high energy proton accelerators carrying the highest beam intensity in the world and the related experimental facilities and therefore provides various issues relevant to the radiation environment. The present report describes the specifications for the radiation control system for the facility, determined in consideration of these characteristics.

  2. Compliance with High-Intensity Radiated Fields Regulations - Emitter's Perspective

    Science.gov (United States)

    Statman, Joseph; Jamnejad, Vahraz; Nguyen, Lee

    2012-01-01

    NASA's Deep Space Network (DSN) uses high-power transmitters on its large antennas to communicate with spacecraft of NASA and its partner agencies. The prime reflectors of the DSN antennas are parabolic, at 34m and 70m in diameter. The DSN transmitters radiate Continuous Wave (CW) signals at 20 kW - 500 kW at X-band and S-band frequencies. The combination of antenna reflector size and high frequency results in a very narrow beam with extensive oscillating near-field pattern. Another unique feature of the DSN antennas is that they (and the radiated beam) move mostly at very slow sidereal rate, essentially identical in magnitude and at the opposite direction of Earth rotation.The DSN is in the process of revamping its documentation to provide analysis of the High Intensity Radiation Fields (HIRF) environment resulting from radio frequency radiation from DSN antennas for comparison to FAA regulations regarding certification of HIRF protection as outlined in the FAA regulations on HIRF protection for aircraft electrical and electronic systems (Title 14, Code of Federal Regulations (14 CFR) [section sign][section sign] 23.1308, 25.1317, 27.1317, and 29.1317).This paper presents work done at JPL, in consultation with the FAA. The work includes analysis of the radiated field structure created by the unique DSN emitters (combination of transmitters and antennas) and comparing it to the fields defined in the environments in the FAA regulations. The paper identifies areas that required special attention, including the implications of the very narrow beam of the DSN emitters and the sidereal rate motion. The paper derives the maximum emitter power allowed without mitigation and the mitigation zones, where required.Finally, the paper presents summary of the results of the analyses of the DSN emitters and the resulting DSN process documentation.

  3. High intensity profile monitor for time resolved spectrometry at the CLIC Test Facility 3

    Science.gov (United States)

    Olvegård, M.; Adli, E.; Braun, H. H.; Bravin, E.; Chritin, N.; Corsini, R.; Dabrowski, A. E.; Döbert, S.; Dutriat, C.; Egger, D.; Lefèvre, T.; Mete, O.; Skowronski, P. K.; Tecker, F.

    2012-08-01

    The power source of the Compact LInear Collider (CLIC) relies on the generation and deceleration of a high-intensity electron drive beam. In order to provide the best radio-frequency (RF) to beam-energy transfer efficiency, the electron beam is accelerated using fully loaded RF cavities, which leads to strong beam loading effects resulting in a high-energy transient. The stability of the RF power produced by the drive beam depends on the stability of the drive beam energy and energy spread along the pulse. The control and the monitoring of the time evolution of the beam energy distribution are therefore crucial for the accelerator performance. For this purpose segmented beam dumps, which are simple and robust devices, have been designed and installed at the CLIC Test Facility 3 (CTF3). These devices are located at the end of spectrometer lines and provide horizontal beam profiles with a time resolution better than 10 ns. The segmented dumps are composed of parallel, vertical, metallic plates, and are based on the same principle as a Faraday cup: the impinging beam current is read by a fast acquisition channel. Both FLUKA and Geant4 simulations were performed to define the optimum detector geometry for beam energies ranging from 5 MeV to 150 MeV. This paper presents a detailed description of the different steps of the design: the optimization of the detector spatial resolution, the minimization of the thermal load and the long-term damage resulting from high radiation doses. Four segmented dumps are currently used in the CTF3 complex. Their measured performance and limitations are presented in this paper. Typical beam spectra as measured in the CTF3 linac are also presented along with a description of the RF manipulations needed for tuning the beam energy spectrum.

  4. Neutron beam design for low intensity neutron and gamma-ray radioscopy using small neutron sources

    CERN Document Server

    Matsumoto, T

    2003-01-01

    Two small neutron sources of sup 2 sup 5 sup 2 Cf and sup 2 sup 4 sup 1 Am-Be radioisotopes were used for design of neutron beams applicable to low intensity neutron and gamma ray radioscopy (LINGR). In the design, Monte Carlo code (MCNP) was employed to generate neutron and gamma ray beams suited to LINGR. With a view to variable neutron spectrum and neutron intensity, various arrangements were first examined, and neutron-filter, gamma-ray shield and beam collimator were verified. Monte Carlo calculations indicated that with a suitable filter-shield-collimator arrangement, thermal neutron beam of 3,900 ncm sup - sup 2 s sup - sup 1 with neutron/gamma ratio of 7x10 sup 7 , and 25 ncm sup - sup 2 s sup - sup 1 with very large neutron/gamma ratio, respectively, could be produced by using sup 2 sup 5 sup 2 Cf(122 mu g) and a sup 2 sup 4 sup 1 Am-Be(37GBq)radioisotopes at the irradiation port of 35 cm from the neutron sources.

  5. Early Beam Injection Scheme for the Fermilab Booster: A Path for Intensity Upgrade

    CERN Document Server

    Bhat, C M

    2015-01-01

    Over the past decade, Fermilab has focused efforts on the intensity frontier physics and is committed to increase the average beam power delivered to the neutrino and muon programs substantially. Many upgrades to the existing injector accelerators, namely, the current 400 MeV LINAC and the Booster, are in progress under the Proton Improvement Plan (PIP). Proton Improvement Plan-II (PIP-II) proposes to replace the existing 400 MeV LINAC by a new 800 MeV LINAC, as an injector to the Booster which will increase Booster output power by nearly a factor of two from the PIP design value by the end of its completion. In any case, the Fermilab Booster is going to play a very significant role for nearly next two decades. In this context, I have developed and investigated a new beam injection scheme called "early injection scheme" (EIS) for the Booster with the goal to significantly increase the beam intensity output from the Booster thereby increasing the beam power to the HEP experiments even before PIP-II era. The sc...

  6. Direct-aperture optimization applied to selection of beam orientations in intensity-modulated radiation therapy

    Science.gov (United States)

    Bedford, J. L.; Webb, S.

    2007-01-01

    Direct-aperture optimization (DAO) was applied to iterative beam-orientation selection in intensity-modulated radiation therapy (IMRT), so as to ensure a realistic segmental treatment plan at each iteration. Nested optimization engines dealt separately with gantry angles, couch angles, collimator angles, segment shapes, segment weights and wedge angles. Each optimization engine performed a random search with successively narrowing step sizes. For optimization of segment shapes, the filtered backprojection (FBP) method was first used to determine desired fluence, the fluence map was segmented, and then constrained direct-aperture optimization was used thereafter. Segment shapes were fully optimized when a beam angle was perturbed, and minimally re-optimized otherwise. The algorithm was compared with a previously reported method using FBP alone at each orientation iteration. An example case consisting of a cylindrical phantom with a hemi-annular planning target volume (PTV) showed that for three-field plans, the method performed better than when using FBP alone, but for five or more fields, neither method provided much benefit over equally spaced beams. For a prostate case, improved bladder sparing was achieved through the use of the new algorithm. A plan for partial scalp treatment showed slightly improved PTV coverage and lower irradiated volume of brain with the new method compared to FBP alone. It is concluded that, although the method is computationally intensive and not suitable for searching large unconstrained regions of beam space, it can be used effectively in conjunction with prior class solutions to provide individually optimized IMRT treatment plans.

  7. Development and application of the intense slow positron beam at IHEP

    Institute of Scientific and Technical Information of China (English)

    WANG Bao-Yi; MA Yan-Yun; WANG Ping; CAO Xing-Zhong; QIN Xiu-So; ZHANG Zhe; YU Run-Sheng; WEI Long

    2008-01-01

    This paper describes the development and application of an intense slow positron beam at IHEP with regard to its two main components.The Variable-Energy Positron Lifetime Spectroscopy (VEPLS) based on the pulsing system consisting of a chopper,a prebuncher and a buncher has been constructed in order to meet the needs of materials science development.At present,the time resolution of the VEPLS can easily reach about 386 ps with a peak-to-background ratio of about 600:1.A plugged-in 22Na positron source section for adjusting the newly built experimental station and for increasing the beam operation efficiency has been constructed.A slow positron beam with an intensity of 2.5x105 e+/s and the beam profile whose diameter is 10 mm has been obtained;the moderation efficiency of the tungsten mesh moderator reaches 5.1x 10-4 as calculated with an original positron source activity of 52 mCi.

  8. Intense electron beams from GaAs photocathodes as a tool for molecular and atomic physics

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Claude

    2009-10-28

    We present cesium-coated GaAs photocathodes as reliable sources of intense, quasi-monoenergetic electron beams in atomic and molecular physics experiments. In long-time operation of the Electron Target of the ion storage ring TSR in Heidelberg, cold electron beams could be realised at steadily improving intensity and reliability. Minimisation of processes degrading the quantum efficiency allowed to increase the extractable current to more than 1mA at usable cathode lifetimes of 24 h or more. The benefits of the cold electron beam with respect to its application to electron cooling and electron-ion recombination experiments are discussed. Benchmark experiments demonstrate the superior cooling force and energy resolution of the photoelectron beam compared to its thermionic counterparts. The long period of operation allowed to study the long-time behaviour of the GaAs samples during multiple usage cycles at the Electron Target and repeated in-vacuum surface cleaning by atomic hydrogen exposure. An electron emission spectroscopy setup has been implemented at the photocathode preparation chamber of the Electron Target. Among others, this new facility opened the way to a novel application of GaAs (Cs) photocathodes as robust, ultraviolet-driven electron emitters. Based on this principle, a prototype of an electron gun, designed for implementation at the HITRAP setup at GSI, has been built and taken into operation successfully. (orig.)

  9. Off-line production of intense {sup 7,10}Be{sup +} beams

    Energy Technology Data Exchange (ETDEWEB)

    Koester, U. E-mail: ulli.koster@cern.ch; Argentini, M.; Catherall, R.; Fedoseyev, V.N.; Gaeggeler, H.W.; Jonsson, O.C.; Weinreich, R

    2003-05-01

    {sup 7}Be and {sup 10}Be were produced by 590 MeV proton bombardment of a graphite target at PSI. Parts of this graphite target were transferred into an ISOLDE target and ion source unit and ionized with the ISOLDE resonance ionization laser ion source. Thus intense radioactive ion beams of 300 nA of {sup 7,10}Be{sup +} were produced off-line.

  10. Off-line production of intense $^{7,10}Be^{+}$ beams

    CERN Document Server

    Köster, U; Catherall, R; Fedosseev, V; Gäggeler, H W; Jonsson, O C; Weinreich, R

    2003-01-01

    $^7$Be and $^{10}$Be were produced by 590~MeV proton bombardment of a graphite target at PSI. Parts of this graphite target were transferred into an ISOLDE target and ion source unit and ionized with the ISOLDE resonance ionization laser ion source (RILIS). Thus intense radioactive ion beams of 300~nA of $^{7,10}$Be$^+$ were produced off-line.

  11. DYNAMICS OF IONIZATION-ENHANCED SPECTRAL EXPANSION IN WATER INDUCED BY AN INTENSE FEMTOSECOND LASER BEAM

    Institute of Scientific and Technical Information of China (English)

    WANG SHU-FENG; QIN YUAN-DONG; YANG HONG; WANG DAN-LING; ZHU CHANG-JUN; GONG QI-HUANG

    2001-01-01

    The dynamic process of white-continuum generation in water was investigated by the pump-probe technique with a femtosecond intense laser at 805nm. The spectrum width of the probe beam was broadened at the blue side and varied with different delay times. This blueshift was attributed to the ionization-enhanced optical nonlinearity, in which both the multi-photon ionization and avalanche ionization had an effect.

  12. Aluminum surface layer strengthening using intense pulsed beam radiation of substrate film system

    Science.gov (United States)

    Klopotov, A. A.; Ivanov, Yu F.; Vlasov, V. A.; Kondratyuk, A. A.; Teresov, A. D.; Shugurov, V. V.; Petrikova, E. A.

    2016-11-01

    The paper presents formation of the substrate film system (Zr-Ti-Cu/Al) by electric arc spraying of cathode having the appropriate composition. It is shown that the intense beam radiation of the substrate film system is accompanied by formation of the multi-phase state, the microhardness of which exceeds the one of pure A7 aluminum by ≈4.5 times.

  13. Role of Density Profiles for the Nonlinear Propagation of Intense Laser Beam through Plasma Channel

    OpenAIRE

    Sonu Sen; Meenu Asthana Varshney; Dinesh Varshney

    2014-01-01

    In this work role of density profiles for the nonlinear propagation of intense laser beam through plasma channel is analyzed. By employing the expression for the dielectric function of different density profile plasma, a differential equation for beamwidth parameter is derived under WKB and paraxial approximation. The laser induces modifications of the dielectric function through nonlinearities. It is found that density profiles play vital role in laser-plasma interaction studies. To have num...

  14. The characteristics of an intense laser beam propagating in a corrugated plasma channel

    Science.gov (United States)

    Tian, Jian-Min; Tang, Rong-An; Hong, Xue-Ren; Yang, Yang; Wang, Li; Zhou, Wei-Jun; Xue, Ju-Kui

    2016-12-01

    The propagation of an intense laser beam in a corrugated plasma channel is investigated. By using the source-dependent expansion technique, an evolution equation of the laser spot size is derived. The behaviors including aperiodic oscillation, resonance, beat-like wave, and periodic oscillation with multipeak are found and analyzed. The formula for the instantaneous wave numbers of these oscillations is obtained. These theoretical findings are confirmed by the final numerical simulation.

  15. Practical Entangled-Photon Virtual-State Spectroscopy using Intense Twin Beams

    OpenAIRE

    2016-01-01

    We propose a new practical approach towards ultrasensitive measurements in chemical and biological systems based on the so-called virtual-state spectroscopy technique. The proposed scheme makes use of intense twin beams generated by pump pulses with different frequency chirps to successfully extract information about the virtual states that contribute to the two-photon excitation of an absorbing medium. Interestingly, we show that our approach may enable entangled-photon absorption rates up t...

  16. Study on Radiation Field Caused by Proton Beam Loss in High Intensity Heavy-ion Accelerator%强流重离子加速器中由于质子束流损失引起的次级辐射场计算研究

    Institute of Scientific and Technical Information of China (English)

    庞成果; 苏有武; 徐俊奎; 李武元; 姚泽恩

    2015-01-01

    The second radiation field outside the vacuum tube caused by proton beam loss in high intensity heavy‐ion accelerator facility (HIAF) with Monte Carlo method was calculated .The energy of proton beam is within 50 MeV to 12 GeV .The basic problems such as second particle yield ,energy spectrum and angular distribution were also discussed .T hese results are beneficial to selecting the detector type and its location and determining its dynamic range for beam loss detector ,as well as to building the beam loss monitor system .Furthermore ,they are meaningful in some way for the radia‐tion protection of accelerator .%本文利用蒙特卡罗方法计算了强流重离子加速器中质子能量在50 M eV~12 GeV能量范围内由于束流损失引起的真空管壁外的次级辐射场,分别就次级粒子的产额、能谱及角分布等方面进行了基本研究。本文的研究结果在束流损失探测器的选择、安装位置以及动态范围的确定上有着重要的参考价值,对于束流损失监测系统的建立有着极为重要的意义。同时,对于加速器的辐射防护问题也有一定的参考价值。

  17. On the stability of a space vehicle riding on an intense laser beam

    CERN Document Server

    Popova, H; Gabitov, I

    2016-01-01

    The Breakthrough Starshot Initiative is suggested to develop the concept of propelling a nano-scale spacecraft by the radiation pressure of an intense laser beam. If such a nanocraft could be accelerated to 20 percent of light speed, it could reach the vicinity of our nearest potentially habitable exoplanet within our life time and capture its images and obtain other scientific data. In this project the nanocraft is a gram-scale robotic spacecraft comprising two main parts: StarChip and Lightsail. To achieve the goal of the project it is necessary to solve a number of outstanding scientific problems. One of these tasks is to make sure that the nanocraft position and orientation inside the intense laser beam column is stable. The nanocraft driven by intense laser beam pressure acting on its Lightsail is sensitive to the torques and lateral forces reacting on the surface of the sail. These forces influence the orientation and lateral displacement of the spacecraft, thus affecting its dynamics. If unstable the n...

  18. Advanced approaches to high intensity laser-driven ion acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Henig, Andreas

    2010-04-26

    Since the pioneering work that was carried out 10 years ago, the generation of highly energetic ion beams from laser-plasma interactions has been investigated in much detail in the regime of target normal sheath acceleration (TNSA). Creation of ion beams with small longitudinal and transverse emittance and energies extending up to tens of MeV fueled visions of compact, laser-driven ion sources for applications such as ion beam therapy of tumors or fast ignition inertial con finement fusion. However, new pathways are of crucial importance to push the current limits of laser-generated ion beams further towards parameters necessary for those applications. The presented PhD work was intended to develop and explore advanced approaches to high intensity laser-driven ion acceleration that reach beyond TNSA. In this spirit, ion acceleration from two novel target systems was investigated, namely mass-limited microspheres and nm-thin, free-standing diamond-like carbon (DLC) foils. Using such ultrathin foils, a new regime of ion acceleration was found where the laser transfers energy to all electrons located within the focal volume. While for TNSA the accelerating electric field is stationary and ion acceleration is spatially separated from laser absorption into electrons, now a localized longitudinal field enhancement is present that co-propagates with the ions as the accompanying laser pulse pushes the electrons forward. Unprecedented maximum ion energies were obtained, reaching beyond 0.5 GeV for carbon C{sup 6+} and thus exceeding previous TNSA results by about one order of magnitude. When changing the laser polarization to circular, electron heating and expansion were shown to be efficiently suppressed, resulting for the first time in a phase-stable acceleration that is dominated by the laser radiation pressure which led to the observation of a peaked C{sup 6+} spectrum. Compared to quasi-monoenergetic ion beam generation within the TNSA regime, a more than 40 times

  19. Cryogenic Current Comparator as Low Intensity Beam Current Monitor in the CERN Antiproton Decelerators

    CERN Document Server

    Fernandes, M; Soby, L; Welsch, CP

    2013-01-01

    In the low-energy Antiproton Decelerator (AD) and the future Extra Low ENergy Antiproton (ELENA) rings at CERN, an absolute measurement of the beam intensity is essential to monitor any losses during the deceleration and cooling phases. However, existing DC current transformers can hardly reach the μA level, while at the AD and ELENA currents can be as low as 100 nA. A Cryogenic Current Comparator (CCC) based on a superconducting quantum interference device (SQUID) is currently being designed and shall be installed in the AD and ELENA machines. It should meet the following specifications: A current resolution smaller than 10 nA, a dynamic range covering currents between 100 nA and 1 mA, as well as a bandwidth from DC to 1 kHz. Different design options are being considered, including the use of low or high temperature superconductor materials, different CCC shapes and dimensions, different SQUID characteristics, as well as electromagnetic shielding requirements. In this contribution we present first results f...

  20. Analyzing the average intensity distribution and beam width evolution of phase-locked partially coherent radial flat-topped array laser beams in oceanic turbulence

    Science.gov (United States)

    Yousefi, M.; Kashani, F. D.; Mashal, A.

    2017-02-01

    In this research, an analytical expression for cross-spectral density matrix elements (and consequently, average intensity) of partially coherent flat-topped (PCFT) radial array laser beams in weak oceanic turbulence are derived based on the extended Huygens-Fresnel principle and the previously developed knowledge of the propagation of a partially coherent beam in atmosphere. Mean-squared beam width is calculated analytically using average intensity formula. The simulation is done by considering the effects of source parameters (such as the radius of the array setup’s circle and effective width of spectral degree of coherence) and turbulent ocean factors (such as the rate of dissipation of the turbulent kinetic energy per unit mass of fluid and relative strength of temperature-salinity fluctuations, Kolmogorov micro-scale, and the rate of dissipation of the mean squared temperature) in detail. It is found that when salinity fluctuations in the ocean dominate temperature fluctuations, the average intensity of the PCFT array beam becomes more broad and the array beam profile conversion process to a single wider Gaussian beam profile will occur at a faster rate. For the same turbulent conditions and the same initial beam width, the divergence of a flat-topped array beam is less than the Gaussian array beam. The simulation and calculation results are shown by graphs.

  1. Condition for production of circulating proton beam with intensity greater than space charge limit.

    Energy Technology Data Exchange (ETDEWEB)

    Vadim Dudnikov

    2002-11-19

    Transverse e-p instability in proton rings could be damped by increasing the beam density and the rate of secondary particles production above the threshold level, with the corresponding decrease of unstable wavelength {lambda} below the transverse beam size h (increase of beam density n{sub b} and ion density n{sub i} above the threshold level: n{sub b} + n{sub i} > {beta}{sup 2}/(r{sub e} h{sup 2}), where r{sub e} = e{sup 2}/mc{sup 2}). Such island of stability can be reached by a fast charge-exchange injection without painting and enhanced generation of secondary plasma, which was demonstrated in a small scale Proton Storage Ring (PSR) at the Institute of Nuclear Physics, Novosibirsk, Russia. With successful damping of e-p instability, the intensity of circulating proton beam, with a space charge neutralization was increased up to 6 times above a space charge limit. Corresponding tune shift without space charge neutralization should be up to {Delta}v=0.85 x 6 (in the ring with v = 0.85). In this paper, they review experimental observations of transverse instability of proton beams in various rings. they also discuss methods which can be used to damp the instability. Such experimental data could be useful for verification of computer simulation tools developed for the studies of the space charge and instabilities in realistic conditions.

  2. Role of Density Profiles for the Nonlinear Propagation of Intense Laser Beam through Plasma Channel

    Directory of Open Access Journals (Sweden)

    Sonu Sen

    2014-01-01

    Full Text Available In this work role of density profiles for the nonlinear propagation of intense laser beam through plasma channel is analyzed. By employing the expression for the dielectric function of different density profile plasma, a differential equation for beamwidth parameter is derived under WKB and paraxial approximation. The laser induces modifications of the dielectric function through nonlinearities. It is found that density profiles play vital role in laser-plasma interaction studies. To have numerical appreciation of the results the propagation equation for plasma is solved using the fourth order Runge-Kutta method for the initial plane wave front of the beam, using boundary conditions. The spot size of the laser beam decreases as the beam penetrates into the plasma and significantly adds self-focusing in plasma. This causes the laser beam to become more focused by reduction of diffraction effect, which is an important phenomenon in inertial confinement fusion and also for the understanding of self-focusing of laser pulses. Numerical computations are presented and discussed in the form of graphs for typical parameters of laser-plasma interaction.

  3. Simulation calculation for the energy deposition profile and the transmission fraction of intense pulsed electron beam at various incident angles

    CERN Document Server

    Yang Hai Liang; Zhang Jia Sheng; Huang Jian Jun; Sun Jian Feng

    2002-01-01

    The incident angles have a heavy effect on the intense pulsed electron beam energy deposition profile, energy deposition fraction and beam current transmission fraction in material. The author presents electron beam energy deposition profile and energy deposition fraction versus electron energy (0.5-2.0 MeV), at various incident angles for three aluminum targets of various thickness via theoretical calculation. The intense pulsed electron beam current transmission fractions versus electron energy (0.4-1.4 MeV) at various incident angles for three thickness of carbon targets were also theoretically calculated. The calculation results indicate that the deposition energy in unit mass of material surface layer increase with the rise of electron beam incident angle, and electron beam with low incident angle (closer to normal incident angle) penetrates deeper into the target material. The electron beams deposit more energy in unit mass of material surface layer at 60 degree-70 degree incident angle

  4. High energy beam impact tests on a LHC tertiary collimator at the CERN high-radiation to materials facility

    Directory of Open Access Journals (Sweden)

    Marija Cauchi

    2014-02-01

    Full Text Available The correct functioning of a collimation system is crucial to safely operate highly energetic particle accelerators, such as the Large Hadron Collider (LHC. The requirements to handle high intensity beams can be demanding. In this respect, investigating the consequences of LHC particle beams hitting tertiary collimators (TCTs in the experimental regions is a fundamental issue for machine protection. An experimental test was designed to investigate the robustness and effects of beam accidents on a fully assembled collimator, based on accident scenarios in the LHC. This experiment, carried out at the CERN High-Radiation to Materials (HiRadMat facility, involved 440 GeV proton beam impacts of different intensities on the jaws of a horizontal TCT. This paper presents the experimental setup and the preliminary results obtained, together with some first outcomes from visual inspection and a comparison of such results with numerical simulations.

  5. Sheet beam model for intense space-charge: with application to Debye screening and the distribution of particle oscillation frequencies in a thermal equilibrium beam

    Energy Technology Data Exchange (ETDEWEB)

    Lund, Steven M.; Friedman, Alex; Bazouin, Guillaume

    2011-01-10

    A one-dimensional Vlasov-Poisson model for sheet beams is reviewed and extended to provide a simple framework for analysis of space-charge effects. Centroid and rms envelope equations including image charge effects are derived and reasonable parameter equivalences with commonly employed 2D transverse models of unbunched beams are established. This sheet beam model is then applied to analyze several problems of fundamental interest. A sheet beam thermal equilibrium distribution in a continuous focusing channel is constructed and shown to have analogous properties to two- d three-dimensional thermal equilibrium models in terms of the equilibrium structure and Deybe screening properties. The simpler formulation for sheet beams is exploited to explicitly calculate the distribution of particle oscillation frequencies within a thermal equilibrium beam. It is shown that as space-charge intensity increases, the frequency distribution becomes broad, suggesting that beams with strong space-charge can have improved stability.

  6. CT to Cone-beam CT Deformable Registration With Simultaneous Intensity Correction

    CERN Document Server

    Zhen, Xin; Yan, Hao; Zhou, Linghong; Jia, Xun; Jiang, Steve B

    2012-01-01

    Computed tomography (CT) to cone-beam computed tomography (CBCT) deformable image registration (DIR) is a crucial step in adaptive radiation therapy. Current intensity-based registration algorithms, such as demons, may fail in the context of CT-CBCT DIR because of inconsistent intensities between the two modalities. In this paper, we propose a variant of demons, called Deformation with Intensity Simultaneously Corrected (DISC), to deal with CT-CBCT DIR. DISC distinguishes itself from the original demons algorithm by performing an adaptive intensity correction step on the CBCT image at every iteration step of the demons registration. Specifically, the intensity correction of a voxel in CBCT is achieved by matching the first and the second moments of the voxel intensities inside a patch around the voxel with those on the CT image. It is expected that such a strategy can remove artifacts in the CBCT image, as well as ensuring the intensity consistency between the two modalities. DISC is implemented on computer g...

  7. Splitting of a high-energy positively-charged particle beam with a bent crystal

    Science.gov (United States)

    Bandiera, L.; Kirillin, I. V.; Bagli, E.; Berra, A.; De Salvador, D.; Guidi, V.; Lietti, D.; Mazzolari, A.; Prest, M.; Shul'ga, N. F.; Sytov, A.; Vallazza, E.

    2017-07-01

    The possibility of high-energy positively-charged particle beam splitting by means of a short bent axially oriented silicon crystal was recently reported in an experiment carried out at CERN SPS H8 extracted line with a 400 GeV/c proton beam. Here, we investigate more deeply such a possibility focusing our attention on the efficiency of beam splitting and its modulation for different crystal-to-beam orientations. New experimental results confirm the possibility of modulating the 400 GeV/c proton beam intensity in different planar channels by adjusting the orientation of the crystal. Furthermore, an analysis of the beam splitting efficiency vs. the curvature of the crystal was carried out through simulation, highlighting that there exists a bending radius for which the efficiency is maximal.

  8. Diagnostics for intense heavy ion beams in the HIF-VNL

    Energy Technology Data Exchange (ETDEWEB)

    Bieniosek, F.M.; Eylon, S.; Faltens, A.; Friedman, A.; Kwan, J.W.; Leitner, M.A.; Molvik, A.W.; Prost, L.; Roy, P.K.; Seidl, P.A.; Westenskow, G.

    2004-06-11

    Modern diagnostic techniques provide detailed information on beam conditions in injector, transport, and final focus experiments in the HIF-VNL. Parameters of interest include beam current, beam energy, transverse and longitudinal distributions, emittance, and space charge neutralization. Imaging techniques, based on kapton films and optical scintillators, complement and in some cases, may replace conventional techniques based on slit scans. Time-resolved optical diagnostics that provide 4-D transverse information on the experimental beams are in operation on the existing experiments. Current work includes a compact optical diagnostic suitable for insertion in transport lines, improved algorithms for optical data analysis and interpretation, a high-resolution electrostatic energy analyzer, and an electron beam probe. A longitudinal diagnostic kicker generates longitudinal space-charge waves that travel on the beam. Time of flight of the space charge waves and an electrostatic energy analyzer provide an absolute measure of the beam energy. Special diagnostics to detect secondary electrons and gases desorbed from the wall have been developed.

  9. A large aperture reflective wave-plate for high-intensity short-pulse laser experiments

    CERN Document Server

    Aurand, Bastian; Zhao, Huanyu; Kuschel, Stephan; Wünsche, Martin; Jäckel, Oliver; Heyer, Martin; Wunderlich, Frank; Kaluza, Malte C; Paulus, Gerhard G; Kuehl, Thomas

    2012-01-01

    We report on a reflective wave-plate system utilizing phase-shifting mirrors (PSM) for a continuous variation of elliptical polarization without changing the beam position and direction. The scalability of multilayer optics to large apertures and the suitability for high-intensity broad-bandwidth laser beams make reflective wave-plates an ideal tool for experiments on relativistic laser-plasma interaction. Our measurements confirm the preservation of the pulse duration and spectrum when a 30-fs Ti:Sapphire laser beam passes the system.

  10. Relativistic electron mirrors from high intensity laser nanofoil interactions

    Energy Technology Data Exchange (ETDEWEB)

    Kiefer, Daniel

    2012-12-21

    The reflection of a laser pulse from a mirror moving close to the speed of light could in principle create an X-ray pulse with unprecedented high brightness owing to the increase in photon energy and accompanying temporal compression by a factor of 4γ{sup 2}, where γ is the Lorentz factor of the mirror. While this scheme is theoretically intriguingly simple and was first discussed by A. Einstein more than a century ago, the generation of a relativistic structure which acts as a mirror is demanding in many different aspects. Recently, the interaction of a high intensity laser pulse with a nanometer thin foil has raised great interest as it promises the creation of a dense, attosecond short, relativistic electron bunch capable of forming a mirror structure that scatters counter-propagating light coherently and shifts its frequency to higher photon energies. However, so far, this novel concept has been discussed only in theoretical studies using highly idealized interaction parameters. This thesis investigates the generation of a relativistic electron mirror from a nanometer foil with current state-of-the-art high intensity laser pulses and demonstrates for the first time the reflection from those structures in an experiment. To achieve this result, the electron acceleration from high intensity laser nanometer foil interactions was studied in a series of experiments using three inherently different high power laser systems and free-standing foils as thin as 3nm. A drastic increase in the electron energies was observed when reducing the target thickness from the micrometer to the nanometer scale. Quasi-monoenergetic electron beams were measured for the first time from ultrathin (≤5nm) foils, reaching energies up to ∝35MeV. The acceleration process was studied in simulations well-adapted to the experiments, indicating the transition from plasma to free electron dynamics as the target thickness is reduced to the few nanometer range. The experience gained from those

  11. Improving the quality of proton beams via double targets driven by an intense circularly polarized laser pulse

    Directory of Open Access Journals (Sweden)

    Yanxia Xu

    2016-10-01

    Full Text Available A new scheme is proposed to improve the quality of proton beams via ultra-intense laser pulse interacting with double plasma targets, which consist of a pre-target with relatively low density and a main target with high density. Both one- and two-dimensional Particle-in-Cell simulations show that, the using of an appropriate pre-target can help to obtain a much stronger longitudinal charge separation field in contrast to using only the main target. And proton beam with lower momentum divergence, better monochromaticity and collimation, as well as higher current density is generated. Moreover, due to the strengthened coupling between the laser pulse and targets, the energy conversion from laser pulse to protons is also increased.

  12. Clinical Realization of Sector Beam Intensity Modulation for Gamma Knife Radiosurgery: A Pilot Treatment Planning Study

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Lijun, E-mail: lijunma@radonc.ucsf.edu [Department of Radiation Oncology, University of California, San Francisco, California (United States); Mason, Erica; Sneed, Penny K.; McDermott, Michael; Polishchuk, Alexei; Larson, David A. [Department of Radiation Oncology, University of California, San Francisco, California (United States); Sahgal, Arjun [Department of Radiation Oncology, Sunnybrook Odette Cancer Center, University of Toronto, Toronto, Ontario (Canada)

    2015-03-01

    Purpose: To demonstrate the clinical feasibility and potential benefits of sector beam intensity modulation (SBIM) specific to Gamma Knife stereotactic radiosurgery (GKSRS). Methods and Materials: SBIM is based on modulating the confocal beam intensities from individual sectors surrounding an isocenter in a nearly 2π geometry. This is in contrast to conventional GKSRS delivery, in which the beam intensities from each sector are restricted to be either 0% or 100% and must be identical for any given isocenter. We developed a SBIM solution based on available clinical planning tools, and we tested it on a cohort of 12 clinical cases as a proof of concept study. The SBIM treatment plans were compared with the original clinically delivered treatment plans to determine dosimetric differences. The goal was to investigate whether SBIM would improve the dose conformity for these treatment plans without prohibitively lengthening the treatment time. Results: A SBIM technique was developed. On average, SBIM improved the Paddick conformity index (PCI) versus the clinically delivered plans (clinical plan PCI = 0.68 ± 0.11 vs SBIM plan PCI = 0.74 ± 0.10, P=.002; 2-tailed paired t test). The SBIM plans also resulted in nearly identical target volume coverage (mean, 97 ± 2%), total beam-on times (clinical plan 58.4 ± 38.9 minutes vs SBIM 63.5 ± 44.7 minutes, P=.057), and gradient indices (clinical plan 3.03 ± 0.27 vs SBIM 3.06 ± 0.29, P=.44) versus the original clinical plans. Conclusion: The SBIM method is clinically feasible with potential dosimetric gains when compared with conventional GKSRS.

  13. High power electron and ion beam research and technology

    Energy Technology Data Exchange (ETDEWEB)

    Nation, J.A.; Sudan, R.N. (eds.)

    1977-01-01

    Topics covered in volume II include: collective accelerators; microwaves and unneutralized E-beams; technology of high-current E-beam accelerators and laser applications of charged-particle beams. Abstracts of twenty-nine papers from the conference were prepared for the data base in addition to six which appeared previously. (GHT)

  14. Stabilizing the intensity of a wave amplified by a beam of particles

    Energy Technology Data Exchange (ETDEWEB)

    Bachelard, R.; Chandre, C.; Leoncini, X.; Vittot, M. [Centre de Physique Theorique, Unite Mixte de Recherche, UMR 6207 du CNRS, et des universites Aix-Marseille-1, Aix-Marseille-2 et du Sud Toulon-Var, Lab. affilie a la FRUMAM (FR 2291), Lab. de Recherche Conventionne du CEA (DSM-06-35), CNRS Luminy, 13 - Marseille (France); Antoniazzi, A.; Fanelli, D. [Firenze Univ., Dipt. di Energetica and CSDC, INFN (Italy); Fanelli, D. [Karolinska Institute, Dept. of Cell and Molecular Biology, Stockholm (Sweden); Leoncini, X. [CNRS-Univ. de Provence, Centre de St Jerome, Physique des Interactions Ioniques et Moleculaires, 13 - Marseille (France)

    2007-04-15

    The intensity of an electromagnetic wave interacting self-consistently with a beam of charged particles as in a free electron laser, displays large oscillations due to an aggregate of particles, called the macro-particle. In this article, we propose a strategy to stabilize the intensity by re-shaping the macro-particle. This strategy involves the study of the linear stability (using the residue method) of selected periodic orbits of a mean-field model. As parameters of an additional perturbation are varied, bifurcations occur in the system which have drastic effect on the modification of the self-consistent dynamics, and in particular, of the macro-particle. We show how to obtain an appropriate tuning of the parameters which is able to strongly decrease the oscillations of the intensity without reducing its mean-value. (authors)

  15. Advances in intense beams, beam delivery, targetry, and radiochemistry at advanced cyclotron systems

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.R. [Advanced Cyclotron Systems Inc., 7851 Alderbridge Way, Richmond, BC, V6X 2A4 (Canada)]. E-mail: djohnson@advancedcyclotron.com; Watt, R. [Advanced Cyclotron Systems Inc., 7851 Alderbridge Way, Richmond, BC, V6X 2A4 (Canada); Kovac, B. [Advanced Cyclotron Systems Inc., 7851 Alderbridge Way, Richmond, BC, V6X 2A4 (Canada); Zyuzin, A. [Advanced Cyclotron Systems Inc., 7851 Alderbridge Way, Richmond, BC, V6X 2A4 (Canada); Van Lier, E. [Advanced Cyclotron Systems Inc., 7851 Alderbridge Way, Richmond, BC, V6X 2A4 (Canada); Erdman, K.L. [Advanced Cyclotron Systems Inc., 7851 Alderbridge Way, Richmond, BC, V6X 2A4 (Canada); Gyles, Wm. [Advanced Cyclotron Systems Inc., 7851 Alderbridge Way, Richmond, BC, V6X 2A4 (Canada); Sabaiduc, V. [Advanced Cyclotron Systems Inc., 7851 Alderbridge Way, Richmond, BC, V6X 2A4 (Canada); McQuarrie, S.A. [Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, T6G 1Z2 (Canada); Wilson, J. [Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, T6G 1Z2 (Canada); Backhouse, C. [Department of Electrical Engineering, University of Alberta, Edmonton, AB (Canada); Gelbart, Wm. [Advanced System Design, C22, S6, RR1, Garden Bay, BC, V0N 1S0 (Canada); Kuo, T. [4654 N. Larwin Ave., Concorde, CA 94521 United States (United States)

    2007-08-15

    The increasing demand for radionuclides for PET and SPECT has resulted in ACSI system improvements starting from the cyclotron and proceeding to the Radiochemistry Modules. With more TR30 cyclotrons installed and operating at full capacity, emphasis has been placed on improving the operational components to reduce both the incidence of failure and subsequent maintenance time. A cyclotron system has been developed that meets the needs of a regional radiopharmacy that supplies both positron and single photon emitters that would not otherwise be available. This new system has been named the TR24. In order to deal with some of the challenges of high currents, a method has been developed for passivating the entrance window foil during high current irradiation of a water target used to produce F-18. A method has been developed for passivating the entrance window foil to reduce unwanted chemical species that interfere with radiopharmaceutical production. Preliminary results for novel radioiodine production technique using the TR19/9 are also discussed.

  16. A research plan based on high intensity proton accelerator Neutron Science Research Center

    Energy Technology Data Exchange (ETDEWEB)

    Mizumoto, Motoharu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    A plan called Neutron Science Research Center (NSRC) has been proposed in JAERI. The center is a complex composed of research facilities based on a proton linac with an energy of 1.5GeV and an average current of 10mA. The research facilities will consist of Thermal/Cold Neutron Facility, Neutron Irradiation Facility, Neutron Physics Facility, OMEGA/Nuclear Energy Facility, Spallation RI Beam Facility, Meson/Muon Facility and Medium Energy Experiment Facility, where high intensity proton beam and secondary particle beams such as neutron, pion, muon and unstable radio isotope (RI) beams generated from the proton beam will be utilized for innovative researches in the fields on nuclear engineering and basic sciences. (author)

  17. Vortex Dynamics and Shear-Layer Instability in High-Intensity Cyclotrons

    Science.gov (United States)

    Cerfon, Antoine J.

    2016-04-01

    We show that the space-charge dynamics of high-intensity beams in the plane perpendicular to the magnetic field in cyclotrons is described by the two-dimensional Euler equations for an incompressible fluid. This analogy with fluid dynamics gives a unified and intuitive framework to explain the beam spiraling and beam breakup behavior observed in experiments and in simulations. Specifically, we demonstrate that beam breakup is the result of a classical instability occurring in fluids subject to a sheared flow. We give scaling laws for the instability and predict the nonlinear evolution of beams subject to it. Our work suggests that cyclotrons may be uniquely suited for the experimental study of shear layers and vortex distributions that are not achievable in Penning-Malmberg traps.

  18. Damage evaluation in metal structures subjected to high energy deposition due to particle beams

    CERN Document Server

    Peroni, L; Dallocchio, A

    2011-01-01

    The unprecedented energy intensities of modern hadron accelerators yield special problems with the materials that are placed close to or into the high intensity beams. The energy stored in a single beam of LHC particle accelerator is equivalent to about 80 kg of TNT explosive, stored in a transverse beam area with a typical value of 0.2 mm×0.2 mm. The materials placed close to the beam are used at, or even beyond, their damage limits. However, it is very difficult to predict structural efficiency and robustness accurately: beam-induced damage for high energy and high intensity occurs in a regime where practical experience does not exist. The interaction between high energy particle beams and metals induces a sudden non uniform temperature increase. This provokes a dynamic response of the structure entailing thermal stress waves and thermally induced vibrations or even the failure of the component. This study is performed in order to estimate the damage on a copper component due to the impact with a 7 TeV pro...

  19. High energy ion beam analysis at ARRONAX

    Energy Technology Data Exchange (ETDEWEB)

    Koumeir, C.; Haddad, F.; Michel, N. [Subatech, Nantes (France); GIP ARRONAX, Saint-Herblain (France); Guertin, A.; Metivier, V.; Michel, N.; Ragreb, D.; Servagent, N. [Subatech, Nantes (France)

    2013-07-01

    Full text: ARRONAX, acronym for 'Accelerator for Research in Radiochemistry and Oncology at Nantes' is a high energy cyclotron. It is characterized by the acceleration of several types of particle beams: 68 MeV alpha, 15-35 MeV deuterons and 30-68 MeV protons. A platform was implemented on ARRONAX to perform non-destructive materials analysis with X and gamma rays emission (PIXE-PIGE). A proper selection of the projectile type and beam energy allows to analyze heavy and light elements in thin and thick samples. Our research activities are oriented along three axes: 1) Measurements of K X-ray production cross section for various elements to complement the databases at high energy. A first experiment has been conducted to measure these cross sections for copper and gold with protons energy between 34 and 68 MeV. 2) Study of the detection sensitivity which depends on the nuclear background and the Bremsstrahlung radiations. A dedicated shielding has been developed and detection limits below tens of μg/g/μC have been assessed using different referenced samples from IAEA. 3) Determination of concentration profile as function of the depth in a thick target. Using layered samples, we have showed for a target consisting of three different layers, the possibility to determine the sequence and thickness of each layer by using X and gamma rays measured respectively during and after irradiation. During this talk, I will present the characteristics and the capabilities of our platform. In the near future we intend to install the PIGE technique and use it with 15 MeV deuterons to analyze lightweight elements. (author)

  20. On the control of filamentation of intense laser beams propagating in underdense plasma

    Energy Technology Data Exchange (ETDEWEB)

    Williams, E A

    2005-10-21

    In indirect drive ICF ignition designs, the laser energy is delivered into the hohlraum through the laser entrance holes (LEH), which are sized as small as practicable to minimize X-ray radiation losses. On the other hand, deleterious laser plasma processes, such as filamentation and stimulated back-scatter, typically increase with laser intensity. Ideally, therefore, the laser spot shape should be a close fit to the LEH, with uniform (envelope) intensity in the spot and minimal energy at larger radii spilling onto the LEH material. This keeps the laser intensity as low as possible consistent with the area of the LEH aperture and the power requirements of the design. This can be achieved (at least for apertures significantly larger than the laser's aberrated focal spot) by the use of custom-designed phase plates. However, outfitting the 192 beam (National Ignition facility) NIF laser with multiple sets of phase plates optimized for a variety of different LEH aperture sizes is an expensive proposition. It is thus important to assess the impact on laser-plasma interaction processes of using phase plates with a smaller than optimum focal spot (or even no phase plates at all!) and then de-focusing the beam to expand it to fill the LEH and lower its intensity. We find significant effects from the lack of uniformity of the laser envelope out of the focal plane, from changes in the characteristic sizes of the laser speckle, and on the efficacy of additional polarization and/or SSD beam smoothing. We quantify these effects with analytic estimates and simulations using our laser plasma interaction code pF3D.

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

    Directory of Open Access Journals (Sweden)

    Adam B. Sefkow

    2007-10-01

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

  2. The SUCIMA project: A status report on high granularity dosimetry and proton beam monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Caccia, M. [Dipartimento di Scienze CC.FF.MM., Universita dell' Insubria, Como (Italy)]. E-mail: Massimo.Caccia@uninsubria.it; Badano, L. [Fondazione per Adroterapia Oncologica, Novara (Italy); Berst, D. [Laboratoire d' Electronique et de Physique des Systemes Instrumentaux, Universite Luis Pasteur, Strasbourg (France); Centre National de la Recherce Scientifique/IN2P3 - Paris (France)] (and others)

    2006-05-01

    The SUCIMA collaboration has been developing instruments and methods for real-time, high granularity imaging of extended electron sources. In particular, dosimetry of intravascular brachytherapy {beta} sources has been intensively studied, together with monitoring of hadrontherapy beams by imaging of secondary electrons emitted by a non-disruptive target. The paper reports the latest results on absolute dosimetry with a large-area silicon strip detectors and on beam monitoring with a hybrid pad sensor.

  3. Generation of intense attosecond x-ray pulses using ultraviolet laser induced microbunching in electron beams

    Directory of Open Access Journals (Sweden)

    D. Xiang

    2009-06-01

    Full Text Available We propose a scheme that combines the echo-enabled harmonic generation technique with the bunch compression and allows one to generate harmonic numbers of a few hundred in a microbunched beam through up-conversion of the frequency of an ultraviolet seed laser. A few-cycle intense laser is used to generate the required energy chirp in the beam for bunch compression and for selection of an attosecond x-ray pulse. Sending this beam through a short undulator results in an intense isolated attosecond x-ray pulse. Using a representative realistic set of parameters, we show that 1 nm x-ray pulse with peak power of a few hundred MW and duration as short as 20 attoseconds (FWHM can be generated from a 200 nm ultraviolet seed laser. The proposed scheme may enable the study of electronic dynamics with a resolution beyond the atomic unit of time (∼24 attoseconds and may open a new regime of ultrafast sciences.

  4. Acceleration of plasma electrons by intense nonrelativistic ion and electron beams propagating in background plasma due to two-stream instability

    Science.gov (United States)

    Kaganovich, Igor D.

    2015-11-01

    In this paper we study the effects of the two-stream instability on the propagation of intense nonrelativistic ion and electron beams in background plasma. Development of the two-stream instability between the beam ions and plasma electrons leads to beam breakup, a slowing down of the beam particles, acceleration of the plasma particles, and transfer of the beam energy to the plasma particles and wave excitations. Making use of the particle-in-cell codes EDIPIC and LSP, and analytic theory we have simulated the effects of the two-stream instability on beam propagation over a wide range of beam and plasma parameters. Because of the two-stream instability the plasma electrons can be accelerated to velocities as high as twice the beam velocity. The resulting return current of the accelerated electrons may completely change the structure of the beam self - magnetic field, thereby changing its effect on the beam from focusing to defocusing. Therefore, previous theories of beam self-electromagnetic fields that did not take into account the effects of the two-stream instability must be significantly modified. This effect can be observed on the National Drift Compression Experiment-II (NDCX-II) facility by measuring the spot size of the extracted beamlet propagating through several meters of plasma. Particle-in-cell, fluid simulations, and analytical theory also reveal the rich complexity of beam- plasma interaction phenomena: intermittency and multiple regimes of the two-stream instability in dc discharges; band structure of the growth rate of the two-stream instability of an electron beam propagating in a bounded plasma and repeated acceleration of electrons in a finite system. In collaboration with E. Tokluoglu, D. Sydorenko, E. A. Startsev, J. Carlsson, and R. C. Davidson. Research supported by the U.S. Department of Energy.

  5. Towards MR-guided high intensity focused ultrasound ablation of liver tumors

    NARCIS (Netherlands)

    Wijlemans, J.W.

    2015-01-01

    Magnetic Resonance-guided High Intensity Focused Ultrasound (MR-HIFU) is a promising technique which can be used for completely non-invasive tissue ablation. The converging ultrasound beam penetrates the skin and subcutaneous tissues with damage, while heating the tissue only in the focal point. The

  6. Status of High Intensity Polarized Electron Gun at Mit-Bates

    Science.gov (United States)

    Tsentalovich, E.; Bessuille, J.; Tiunov, M.

    2011-01-01

    MIT-Bates, in collaboration with BNL, has developed a high intensity polarized electron gun for the eRHIC project. The gun implements large area cathode, ring-shaped beam and active cathode cooling. The paper describes the current status of the project.

  7. Recent Experiments At Ndcx-II: Irradiation Of Materials Using Short, Intense Ion Beams

    CERN Document Server

    Seidl, P A; Persaud, A; Feinberg, E; Ludewigt, B; Silverman, M; Sulyman, A; Waldron, W L; Schenkel, T; Barnard, J J; Friedman, A; Grote, D P; Gilson, E P; Kaganovich, I D; Stepanov, A; Treffert, F; Zimmer, M

    2016-01-01

    We present an overview of the performance of the Neutralized Drift Compression Experiment-II (NDCX-II) accelerator at Berkeley Lab, and summarize recent studies of material properties created with nanosecond and millimeter-scale ion beam pulses. The scientific topics being explored include the dynamics of ion induced damage in materials, materials synthesis far from equilibrium, warm dense matter and intense beam-plasma physics. We summarize the improved accelerator performance, diagnostics and results of beam-induced irradiation of thin samples of, e.g., tin and silicon. Bunches with over 3x10^10 ions, 1- mm radius, and 2-30 ns FWHM duration have been created. To achieve these short pulse durations and mm-scale focal spot radii, the 1.2 MeV He+ ion beam is neutralized in a drift compression section which removes the space charge defocusing effect during final compression and focusing. Quantitative comparison of detailed particle-in-cell simulations with the experiment play an important role in optimizing acc...

  8. Intense laser-driven proton beam energy deposition in compressed and uncompressed Cu foam

    Science.gov (United States)

    McGuffey, Christopher; Krauland, C. M.; Kim, J.; Beg, F. N.; Wei, M. S.; Habara, H.; Noma, S.; Ohtsuki, T.; Tsujii, A.; Yahata, K.; Yoshida, Y.; Uematsu, Y.; Nakaguchi, S.; Morace, A.; Yogo, A.; Nagatomo, H.; Tanaka, K.; Arikawa, Y.; Fujioka, S.; Shiraga, H.

    2016-10-01

    We investigated transport of intense proton beams from a petawatt laser in uncompressed or compressed Cu foam. The LFEX laser (1 kJ on target, 1.5 ps, 1053 nm, I >2×1019 W/cm2) irradiated a curved C foil to generate the protons. The foil was in an open cone 500 μm from the tip where the focused proton beam source was delivered to either of two Cu foam sample types: an uncompressed cylinder (1 mm L, 250 µm ϕ) , and a plastic-coated sphere (250 µm ϕ) that was first driven by GXII (9 beams, 330 J/beam, 1.3 ns, 527 nm) to achieve similar ρϕ to the cylinder sample's ρL as predicted by 2D radiation hydrodynamic simulations. Using magnetic spectrometers and a Thomson parabola, the proton spectra were measured with and without the Cu samples. When included, they were observed using Cu K-shell x-ray imaging and spectroscopy. This paper will present comparison of the experimentally measured Cu emission shape and proton spectrum changes due to deposition in the Cu with particle-in-cell simulations incorporating new stopping models. This work was made possible by laser time Awarded by the Japanese NIFS collaboration NIFS16KUGK107 and performed under the auspices of the US AFOSR YIP Award FA9550-14-1-0346.

  9. A nested partitions framework for beam angle optimization in intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    D' Souza, Warren D; Nazareth, Daryl P [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD (United States); Zhang, Hao H; Shi Leyuan [Department of Industrial and Systems Engineering, University of Wisconsin, Madison, WI (United States); Meyer, Robert R [Computer Sciences Department, University of Wisconsin, Madison, WI (United States)], E-mail: dsouzaw@ohsu.edu

    2008-06-21

    Coupling beam angle optimization with dose optimization in intensity-modulated radiation therapy (IMRT) increases the size and complexity of an already large-scale combinatorial optimization problem. We have developed a novel algorithm, nested partitions (NP), that is capable of finding suitable beam angle sets by guiding the dose optimization process. NP is a metaheuristic that is flexible enough to guide the search of a heuristic or deterministic dose optimization algorithm. The NP method adaptively samples from the entire feasible region, or search space, and coordinates the sampling effort with a systematic partitioning of the feasible region at successive iterations, concentrating the search in promising subsets. We used a 'warm-start' approach by initiating NP with beam angle samples derived from an integer programming (IP) model. In this study, we describe our implementation of the NP framework with a commercial optimization algorithm. We compared the NP framework with equi-spaced beam angle selection, the IP method, greedy heuristic and random sampling heuristic methods. The results of the NP approach were evaluated using two clinical cases (head and neck and whole pelvis) involving the primary tumor and nodal volumes. Our results show that NP produces better quality solutions than the alternative considered methods.

  10. A nested partitions framework for beam angle optimization in intensity-modulated radiation therapy

    Science.gov (United States)

    D'Souza, Warren D.; Zhang, Hao H.; Nazareth, Daryl P.; Shi, Leyuan; Meyer, Robert R.

    2008-06-01

    Coupling beam angle optimization with dose optimization in intensity-modulated radiation therapy (IMRT) increases the size and complexity of an already large-scale combinatorial optimization problem. We have developed a novel algorithm, nested partitions (NP), that is capable of finding suitable beam angle sets by guiding the dose optimization process. NP is a metaheuristic that is flexible enough to guide the search of a heuristic or deterministic dose optimization algorithm. The NP method adaptively samples from the entire feasible region, or search space, and coordinates the sampling effort with a systematic partitioning of the feasible region at successive iterations, concentrating the search in promising subsets. We used a 'warm-start' approach by initiating NP with beam angle samples derived from an integer programming (IP) model. In this study, we describe our implementation of the NP framework with a commercial optimization algorithm. We compared the NP framework with equi-spaced beam angle selection, the IP method, greedy heuristic and random sampling heuristic methods. The results of the NP approach were evaluated using two clinical cases (head and neck and whole pelvis) involving the primary tumor and nodal volumes. Our results show that NP produces better quality solutions than the alternative considered methods.

  11. Increasing the intensity of an induction accelerator and reduction of the beam breakup instability

    Directory of Open Access Journals (Sweden)

    J. E. Coleman

    2014-03-01

    Full Text Available A 7 cm cathode has been deployed for use on a 3.8 MV, 80 ns (FWHM Blumlein, to increase the extracted electron current from the nominal 1.7 to 2.9 kA. The intense relativistic electron bunch is accelerated and transported through a nested solenoid and ferrite induction core lattice consisting of 64 elements, exiting the accelerator with a nominal energy of 19.8 MeV. The principal objective of these experiments is to quantify the space-charge limitations on the beam quality, its coupling with the beam breakup (BBU instability, and provide an independent validation of the BBU theory in a higher current regime, I>2  kA. Time resolved centroid measurements indicate a reduction in BBU >10× with simply a 50% increase in the average B-field used to transport the beam through the accelerator. A qualitative comparison of experimental and calculated results are presented, which include time resolved current density distributions, radial BBU amplitude relative to the calculated beam envelope, and frequency analyzed BBU amplitude with different accelerator lattice tunes.

  12. Beam Comissioning of the PEP-II High Energy Ring

    Energy Technology Data Exchange (ETDEWEB)

    Wienands, U.; Anderson, S.; Assmann, R.; Bharadwaj, V.; Cai, Y.; Clendenin, J.; Corredoura, P.; Decker, F.J.; Donald, M.; Ecklund, S.; Emma, P.; Erickson, R.; Fox, J.; Fieguth, T.; Fisher, A.; Heifets,, S.; Hill, A.; Himel, T.; Iverson, R.; Johnson, R.; Judkins, J.; Krejcik, P.; Kulikov, A.; Lee, M.; Mattison, T.; Minty, M.; Nosochkov, Y.; Phinney, N.; Placidi, M.; Prabhakar, S.; Ross, M.; Smith, S.; Schwarz, H.; Stanek, M.; Teytelman, D.; Traller, R.; Turner, J.; Zimmermann, F.; Barry, W.; Chattopadhyay, S.; Corlett, J.; Decking, W.; Furman, M.; Nishimura, H.; Portmann, G.; Rimmer, R.; Zholents, A.; Zisman, M.; Kozanecki, W.; Hofmann, A.; Zotter, B.; Steier, C.; Bialowons, W.; Lomperski, M.; Lumpkin, A.; Reichel, I.; Safranek, J.; Smith, V.; Tighe, R.; Sullivan, M.; Byrd, J.; Li, D.

    1998-11-12

    The PEP-II High Energy Ring (HER), a 9 GeV electron storage ring, has been in commissioning since spring 1997. Initial beam commissioning activities focused on systems checkout and commissioning and on determining the behavior of the machine systems at high beam currents. This phase culminated with the accumulation of 0.75 A of stored beam-sufficient to achieve design luminosity--in January 1998 after 3.5 months of beam time. Collisions with the 3 GeV positron beam of the Low Energy Ring (LER) were achieved in Summer of 1998. At high beam currents, collective instabilities have been seen. Since then, commissioning activities for the HER have shifted in focus towards characterization of the machine and a rigorous program to understand the machine and the beam dynamics is presently underway.

  13. The Buffer Gas Beam: An Intense, Cold, and Slow Source for Atoms and Molecules

    CERN Document Server

    Hutzler, Nicholas R; Doyle, John M

    2011-01-01

    Beams of atoms and molecules are stalwart tools for spectroscopy and studies of collisional processes. The supersonic expansion technique can create cold beams of many species of atoms and molecules. However, the resulting beam is typically moving at a speed of 300-600 m/s in the lab frame, and for a large class of species has insufficient flux (i.e. brightness) for important applications. In contrast, buffer gas beams can be a superior method in many cases, producing cold and relatively slow molecules in the lab frame with high brightness and great versatility. There are basic differences between supersonic and buffer gas cooled beams regarding particular technological advantages and constraints. At present, it is clear that not all of the possible variations on the buffer gas method have been studied. In this review, we will present a survey of the current state of the art in buffer gas beams, and explore some of the possible future directions that these new methods might take.

  14. Intensity Modulated Proton Beam Radiation for Brachytherapy in Patients With Cervical Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Clivio, Alessandro [Oncology Institute of Southern Switzerland, Bellinzona (Switzerland); Kluge, Anne [Department of Radiation Oncology, Charité University Hospital, Berlin (Germany); Cozzi, Luca, E-mail: lucozzi@iosi.ch [Oncology Institute of Southern Switzerland, Bellinzona (Switzerland); Köhler, Christhardt [Department of Gynecology, Charité University Hospital, Berlin (Germany); Neumann, Oliver [Department of Radiation Oncology, Charité University Hospital, Berlin (Germany); Vanetti, Eugenio [Oncology Institute of Southern Switzerland, Bellinzona (Switzerland); Wlodarczyk, Waldemar; Marnitz, Simone [Department of Radiation Oncology, Charité University Hospital, Berlin (Germany)

    2013-12-01

    Purpose: To evaluate intensity modulated proton therapy (IMPT) in patients with cervical cancer in terms of coverage, conformity, and dose–volume histogram (DVH) parameters correlated with recommendations from magnetic resonance imaging (MRI)-guided brachytherapy. Methods and Materials: Eleven patients with histologically proven cervical cancer underwent primary chemoradiation for the pelvic lymph nodes, the uterus, the cervix, and the parametric region, with a symmetric margin of 1 cm. The prescription was for 50.4 Gy, with 1.8 Gy per fraction. The prescribed dose to the parametria was 2.12 Gy up to 59.36 Gy in 28 fractions as a simultaneous boost. For several reasons, the patients were unable to undergo brachytherapy. As an alternative, IMPT was planned with 5 fractions of 6 Gy to the cervix, including the macroscopic tumor with an MRI-guided target definition, with an isotropic margin of 5 mm for planning target volume (PTV) definition. Groupe-Europeen de Curietherapie and European society for Radiotherapy and Oncology (GEC-ESTRO) criteria were used for DVH evaluation. Reference comparison plans were optimized for volumetric modulated rapid arc (VMAT) therapy with the RapidArc (RA). Results: The dose to the high-risk volume was calculated with α/β = 10 with 89.6 Gy. For IMPT, the clinical target volume showed a mean dose of 38.2 ± 5.0 Gy (35.0 ±1.8 Gy for RA). The D{sub 98%} was 31.9 ± 2.6 Gy (RA: 30.8 ± 1.0 Gy). With regard to the organs at risk, the 2Gy Equivalent Dose (EQD2) (α/β = 3) to 2 cm{sup 3} of the rectal wall, sigmoid wall, and bladder wall was 62.2 ± 6.4 Gy, 57.8 ± 6.1 Gy, and 80.6 ± 8.7 Gy (for RA: 75.3 ± 6.1 Gy, 66.9 ± 6.9 Gy, and 89.0 ± 7.2 Gy, respectively). For the IMPT boost plans in combination with external beam radiation therapy, all DVH parameters correlated with <5% risk for grades 2 to 4 late gastrointestinal and genitourinary toxicity. Conclusion: In patients who are not eligible for brachytherapy, IMPT as a boost

  15. Proton Acceleration Drived by High-intensity Ultraviolet Laser

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The generation of energetic protons from a solid thin-foil by the interactions of ultra-short and intense laser pulses is investigated in numerous experiments in the last decade. The energetic proton beams are promising candidates for proton fast ignitor (PFI)

  16. High-intensity sweeteners and energy balance.

    Science.gov (United States)

    Swithers, Susan E; Martin, Ashley A; Davidson, Terry L

    2010-04-26

    Recent epidemiological evidence points to a link between a variety of negative health outcomes (e.g. metabolic syndrome, diabetes and cardiovascular disease) and the consumption of both calorically sweetened beverages and beverages sweetened with high-intensity, non-caloric sweeteners. Research on the possibility that non-nutritive sweeteners promote food intake, body weight gain, and metabolic disorders has been hindered by the lack of a physiologically-relevant model that describes the mechanistic basis for these outcomes. We have suggested that based on Pavlovian conditioning principles, consumption of non-nutritive sweeteners could result in sweet tastes no longer serving as consistent predictors of nutritive postingestive consequences. This dissociation between the sweet taste cues and the caloric consequences could lead to a decrease in the ability of sweet tastes to evoke physiological responses that serve to regulate energy balance. Using a rodent model, we have found that intake of foods or fluids containing non-nutritive sweeteners was accompanied by increased food intake, body weight gain, accumulation of body fat, and weaker caloric compensation, compared to consumption of foods and fluids containing glucose. Our research also provided evidence consistent with the hypothesis that these effects of consuming saccharin may be associated with a decrement in the ability of sweet taste to evoke thermic responses, and perhaps other physiological, cephalic phase, reflexes that are thought to help maintain energy balance.

  17. Study on fundamental processes of laser welded metals observed with intense x-ray beams

    Science.gov (United States)

    Muramatsu, T.; Daido, H.; Shobu, T.; Takase, K.; Tsukimori, K.; Kureta, M.; Segawa, M.; Nishimura, A.; Suzuki, Y.; Kawachi, T.

    With use of photon techniques including visible light, soft and hard x-rays, precise fundamental laser welding processes in the repair and maintenance of nuclear plant engineering were reviewed mechanistically. We make discussions centered on the usefulness of an intense soft x-ray beams for evaluations of spatial residual strain distribution and welded metal convection behavior including the surface morphology. Numerical results obtained with a general purpose three-dimensional code SPLICE for the simulation of the welding and solidifying phenomena. Then it is concluded that the x-ray beam would be useful as one of the powerful tools for understanding the mechanisms of various complex phenomena with higher accuracy and higher resolution.

  18. Non-dissociative and dissociative ionization of a CO+ beam in intense ultrashort laser pulses

    Science.gov (United States)

    Gaire, B.; Ablikim, U.; Zohrabi, M.; Roland, S.; Carnes, K. D.; Ben-Itzhak, I.

    2011-05-01

    We have investigated the ionization of CO+ beams in intense ultrashort laser pulses. With the recent upgrades to our coincidence three-dimensional momentum imaging method we are able to measure both non-dissociative and dissociative ionization of the molecular-ion beam targets. Using CO+ as an example, we have found that non-dissociative ionization (leading to the metastable dication CO2+) involves a direct transition, i.e. the molecule is ionized with little or no internuclear distance stretch. Dissociative ionization (C+ + O+) occurs both directly and indirectly, stretching first and then ionizing. Our results show that the yield of dissociative ionization is higher than that of non-dissociative ionization and can be manipulated with the laser pulse duration by suppressing the indirect ionization path using ultrashort pulses (Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy.

  19. A compact x-ray beam intensity monitor using gas amplified sample current measurement

    Science.gov (United States)

    Hayakawa, Shinjiro; Kobayashi, Kazuo; Gohshi, Yohichi

    2000-01-01

    Development of a compact beam intensity monitor using gas amplified sample current measurement is described. The monitor can be a powerful tool for x-ray spectroscopy and microscopy when the beam is defined by a small pinhole or slits and when the workspace around the sample is limited. The thickness of the monitor is as small as approximately 3 mm, and the dimension is 10 mm square. The photon flux is monitored by measuring x-ray excited current from an Al foil under atmospheric conditions. Emitted electrons from the Al foil can ionize surrounding air molecules, and the gas amplified current can be measured with the use of a biased grid that prevents created ion pairs from recombination.

  20. Proceedings of the workshop on the science of intense radioactive ion beams

    Energy Technology Data Exchange (ETDEWEB)

    McClelland, J.B.; Vieira, D.J. (comps.)

    1990-10-01

    This report contains the proceedings of a 2-1/2 day workshop on the Science of Intense Radioactive Ion Beams which was held at the Los Alamos National Laboratory on April 10--12, 1990. The workshop was attended by 105 people, representing 30 institutions from 10 countries. The thrust of the workshop was to develop the scientific opportunities which become possible with a new generation intense Radioactive Ion Beam (RIB) facility, currently being discussed within North America. The workshop was organized around five primary topics: (1) reaction physics; (2) nuclei far from stability/nuclear structure; (3) nuclear astrophysics; (4) atomic physics, material science, and applied research; and (5) facilities. Overview talks were presented on each of these topics, followed by 1-1/2 days of intense parallel working group sessions. The final half day of the workshop was devoted to the presentation and discussion of the working group summary reports, closing remarks and a discussion of future plans for this effort.